If extremely long lives are going to become possible, it will be necessary to discover effective means for averting or delaying immunosenescence, the process of the immune system losing functionality with advanced aging. This is a mini-treatise on immunosenescence.  It  looks at immunosenescence from a few key perspectives and discusses possible approaches for delaying it and possibly averting it entirely in the future.  

“Immunosenescence refers to the gradual deterioration of the immune system brought on by natural age advancement. It involves both the host’s capacity to respond to infections and the development of long-term immune memory, especially by vaccination ^[1]. This age-associated immune deficiency is ubiquitous and found in both long- and short-living species as a function of their age relative to life expectancy rather than chronological time ^[2]. It is considered a major contributory factor to the increased frequency of morbidity and mortality among the elderly(ref).” 

Immunology is a complex subject so let me set the context for this discussion.  There is an innate immune system involving cells and mechanisms that defend the host from infection by other organisms, in a non-specific manner, and an adaptive immune system that learns about specific threats, develops means to deal with these threats and remembers the threats and responses to them.  Aging affects both immune systems but I am concerned here mostly with the adaptive immune system.

What happens in immunosenescence is that with aging the immune system becomes less capable of dealing with new disease challenges and at the same time typically becomes more autoimmune reactive. Observable biological changes are many including deregulation of T cell functions, decline in rates of T cell progenitor reproduction and differentiation resulting in reduced rates of T cell renewal, decline in  the antigen-presenting function of dendritic cells resulting in T-lymphocytes having a reduced capability to generate an adaptive immune response , decline in the toxicity of Natural Killer (NK) cells, and resulting in a decline in cell-mediated immunity.  See here for more details. 

Evolutionary perspective

Starting with the philosophical, from an evolutionary perspective immunosenescence is the result of design compromises favoring younger animals over older ones.  According to this time-worn argument, survival is best optimized for animals which are young enough to be still engaged in child rearing.  From the publication “Biomarkers of immunosenescence within an evolutionary perspective: the challenge of heterogeneity and the role of antigenic load:”   “On the whole, immunosenescence can be taken as a proof that the beneficial effects of the immune system, devoted to the neutralization of dangerous/harmful agents early in life and in adulthood, turn to be detrimental late in life, in a period largely not foreseen by evolution. This perspective fits with basic assumptions of evolutionary theories of aging, such as antagonistic pleiotropy.” The antagonistic pleiotropy theory of aging holds that “if a gene caused both increased reproduction in early life and aging in later life, then senescence would be adaptive in evolution.” 

This all reminds me of the traditional Detroit auto-company philosophy of building cars: “We build them so they last and look good for 2-3 years; after that, we don’t care.  In fact, we want to build-in obsolescence so our customers will have to come back and buy newer models.”   Japanese-initiated total-quality engineering finally required Detroit to drop that approach in favor of much longer-lived cars.  We can possibly do something similar for people. 

In the blog entry Social Ethics of Longevity, I pointed out that the antagonistic pleiotropy way of thinking takes biological evolution into account but not social evolution, and that social evolution is reflecting back on biological evolution in a way that is making human lifespan longer and longer. So whatever the genetic shortcuts have been that lead to early immunosenescence, they are already being re-engineered by evolution so our immune systems last longer.  The question is whether they can be re-engineered consciously so our immune systems last a lot longer.

Cellular memory perspective

From a cellular memory perspective, put crudely the immune systems of older people are too clogged up with memories of older threats and not sufficiently open to newer threats and ready and able to deal with them.  Immunological memory is a function of the adaptive immune system.  “The adaptive immune response provides the vertebrate immune system with the ability to recognize and remember specific pathogens (to generate immunity), and to mount stronger attacks each time the pathogen is encountered(ref). “  The operation of the adaptive immune system is quite complex(ref) involving interactions of multiple immune system cells including antigen-presenting cells like dendritic cells, B cells and macrophages with T cells. “Adaptive immunity is triggered in vertebrates when a pathogen evades the innate immune system and generates a threshold level of antigen.^[1]  The major functions of the adaptive immune system include:

• The recognition of specific “non-self” antigens in the presence of “self”, during the process of antigen presentation.
• the generation of responses that are tailored to maximally eliminate specific pathogens or pathogen infected cells.
• the development of immunological memory, in which each pathogen is “remembered” by a signature antibody. These memory cells can be called upon to quickly eliminate a pathogen should subsequent infections occur(ref).”

Vaccination is one way of deliberately introducing immunological memory.

“The cells of the adaptive immune system are a type of leukocyte, called a lymphocyte. B cells and T cells are the major types of lymphocytes. The human body has about 2 trillion lymphocytes, constituting 20-40% of white blood cells (WBCs); their total mass is about the same as the brain or liver.^[2] The peripheral blood contains 20–50% of circulating lymphocytes; the rest move within the lymphatic system(ref).^[2]”

With aging, the adaptive immune system develops a memory bank of antigens representing potential threats identified over a lifetime, and at the same time loses capability to recognize and deal with new threats.  There are too many irrelevant old memories.  “In this review, recent data are discussed under the hypothesis that human immunosenescence is the consequence of the continuous attrition caused by chronic antigenic overload/stress. — Thus, immunosenescence can be envisaged as a global reduction of the “immunological space(ref).”   

Various explanations of the underlying molecular mechanisms have been put forward.    An early (1997) explanation was “that aging is associated with the emergence of an unusual CD4 T cell subset characterized by the loss of CD28 expression.” –. “We propose that the emergence of CD28-deficient CD4 T cells in the elderly can partially explain age-specific aberrations in immune responsiveness(ref).” A 1997 mouse study suggested “Importantly, addition of IL-2 restores proliferation of aged naive T cells, restores efficient effector generation and results in effectors seemingly indistinguishable from those derived from young CD4 cells.”  “– the loss of optimal IL-2 production may participate in the aging process and may represent the main antigen-independent defect in the CD4 T-cell population(ref).”   

Another explanation is suggested in the publication Failing immune control as a result of impaired CD8+ T-cell maturation: CD27 might provide a clue.  A 2003 publication Lack of proliferative capacity of human effector and memory T cells expressing killer cell lectinlike receptor G1 (KLRG1) suggest that “the expression of KLRG1 identifies a subset of NK cells and antigen-experienced T cells in humans that lack proliferative capacity.”  Another study casts a lot of the blame on herpes viruses.  “Thus, T cell responses are altered in the aged by an accumulation of replicatively senescent dysfunctional T cells carrying receptors for persistent herpes viruses. The presence of clonal expansions of such virus-specific cells may shrink the available repertoire for other antigens and contribute to the increased incidence of infectious disease in the elderly(ref)  Another study implicates cytomegalovirus in a somewhat similar fashion.  “At the same time, it was established that cytomegalovirus (CMV) seropositivity was associated with many of the same phenotypic and functional alterations to T-cell immunity that were being reported as biomarkers associated with aging. It was discovered that CMV was the prime driving force behind most of the oligoclonal expansions and altered phenotypes and functions of CD8 cells. Independently, longitudinal studies of a free-living population of the very old in Sweden over the past decade have led to the emerging concept of an ‘immune risk phenotype’ (IRP), predicting mortality, which was itself found to be associated with CMV seropositivity. — In this sense, then, we suggest that immunosenescence is contagious (ref).”

From an evolutionary viewpoint, the difficulty experienced by  mature adaptive immune systems when dealing with brand new pathogens is explained by the fact that until recent years there was very little mobility of people and therefore of human pathogens.  Human diseases traveled by foot or ox cart. There was no such thing as a disease originating in Borneo and spreading all over the world in weeks because of air travel.  So, the adaptive immune system rarely had to deal with new off-the-wall challenges like the new H1N1 virus.

Some of the responsibility for immunosenescence is associated with changes in antigen-presenting cells. “Recent findings suggest that interleukin-10, a key cytokine that can suppress cell mediated immunity and maturation of DC subsets, is elevated in the very healthy elderly. However, production of IL-12, required for the initiation of T cell immune responses, declines in frail elderly along with DC antigen presenting function. These findings suggest that shifts in IL-10 and IL-12 may not only directly influence immune response but may also alter the balance and maturation of DC subsets(ref).  Another early study related to antigen presenting cells provided a clue of things to be explained later – that there is something about young immune system cells that invigorates older ones.  “Surprisingly, co-culture of APC (antigen presenting cells) from healthy elderly donors with purified T cells from young donors enhanced T cell proliferation(ref).”

Whatever the age-associated mechanisms, there are a few recurring themes in the earlier literature (pre 2006): 1.  too many antigen memories producing overload,  3. Cellular senescence of T and B cells, 3. insufficient proliferation of new T cells, and 4. Decline in the antigen presenting function.

Stem cell proliferation perspective

From the stem cell perspective the main issue of immunosenescence is decline of proliferation of new T cells as identified earlier.  But the focus is on decline of the rate of differentiation of hematopoietic stem cells into immune system progenitor cells and subsequent proliferation and differentiation of those cells into immune system cells in the thymus. “The thymus is the site of production of mature T lymphocytes and thus is indispensable for the development and maintenance of the T cell–mediated arm of the immune system. Thymic production of mature T cells is critically dependent on an influx of bone marrow-derived progenitor T cells that undergo replication and selection within the thymus. Thymus cellularity and thymic hormone secretion reach a peak during the first year of life and then decline gradually until the age of 50–60 years, a process known as “thymic involution(ref).”  In this regard,  immunosenescence falls under the 14^th theory of aging outlined in my treatise, Stem Cell Supply Chain Breakdown.  In fact, decline of thymus function has long been thought to be associated with aging(ref).

The stem cell perspective of immunosenescence started to emerge into prominence in recent years. A 2006 publication indicates “The differentiation state of CD8+ T cells has emerged as a crucial determinant of their ability to respond to tumor and infection. Signals from T-cell receptors, co-stimulatory molecules and cytokine receptors direct the differentiation process. These signals ‘program’ sustained and heritable gene expression patterns that govern progressive differentiation and lineage commitment. The epigenetic mechanisms by which T cells are programmed are just beginning to be elucidated. Understanding the mechanisms that control CD8+ T-cell differentiation is important in the development of novel immunotherapy strategies(ref).”  As time goes on, more is being learned about aspects of the stem cell supply chain that ends up in production of T cells.  See, for example, the publications Differentiation of memory B and T cells, Major T Cell Progenitor Activity in Bone Marrow–derived Spleen Colonies, and Identification of an early T cell progenitor for a pathway of T cell maturation in the bone marrow.

Notch signaling and the transcription factor GATA-binding protein GATA3 seems to be very important for determining the kinds of immune cells neural precursor cells differentiate into in the thymus.   The nature of this signaling  has been studied intensively.  For example, see the publications Different thresholds of Notch signaling bias human precursor cells toward B-, NK-, monocytic/dendritic-, or T-cell lineage in thymus microenvironment, Hierarchy of Notch–Delta interactions promoting T cell lineage commitment and maturation, Active form of Notch imposes T cell fate in human progenitor cells, Competition and collaboration: GATA-3, PU.1, and Notch signaling in early T-cell fate determination, Mast cell lineage diversion of T lineage precursors by the essential T cell transcription factor GATA-3, and GATA3 and the T-cell lineage: essential functions before and after T-helper-2-cell differentiation.

I have mentioned the role of notch signaling in stem cell differentiation in the previous post On cancer stem cells.  Also, in discussion of the 14 theory of aging in my treatise, Stem Cell Supply Chain Breakdown, I state “Although the mobilization responsiveness of Type C stem cells declines with age, it appears that their regenerative capability can be restored through environmental messages or induction of Notch activity.”  Whether and how this might be applied for postponement of immunosenescence is unclear as of now.

It appears clear that averting immunosenescence requires a continuing high level of healthy operability of the stem cell supply chain leading from hematopoietic stem cells to operating immune system cells, T cells in particular.  Further, it is important to avert depletion of the stocks of hematopoietic stem cells themselves.   These topics are treated at some length in my treatise as part of the discussion of the Stem Cell Supply Chain Breakdown theory of aging.  See particularly the discussion in the subsection on Exhaustion of critical pools of healthy adult stem cells.

Epigenetic perspective

The accumulation of too-many memories in immune cells mentioned earlier as well as the operation and evolution of the stem cell supply chain that makes new immune system cells are both epigenomic phenomena.  They have to do with histone acetylation and DNA methylation and protein folding changes in the DNA of cells that profoundly affect gene expression but that are not in the genes themselves.  As elaborated in my treatise “The Deterioration of the Stem Cell Supply Chain and the Programmed Epigenomic Changes and the candidate Epigenomic Changes In DNA Methylation and Histone Acetylation theories of aging are completely compatible and complementary.

What can be done about immunosenescence?

Telomerase activation

I have previously discussed one possible approach for combating immunosenescence: promotion of the expression of  telomerase.  This could produce  three desirable consequences: 1. Extending the replicative lifespan of existing immune system cells, 2. Promoting the chain of differentiation starting with hematopoietic stem cells leading through neural progenitor cells and ending with operable immune system cells, and 3. Possibly expanding the replicative lifespan of hematopoietic stem cells thus assuring greater longevity of the pools of those cells.  See the discussion in my treatise in the Telomere Shortening and Damage Firewall section and some of the publications that Rita Effros and her team have produced related to telomerase activation in immune system cells like this one, this one and this one. “Our research has documented that maintaining high levels of the telomere-extending enzyme, telomerase, by either genetic manipulation or exposure of T cells to chemical telomerase activators, not only retards telomere loss but also restores a more youthful functional profile to the T cells. These observations suggest possible novel telomerase-based therapeutic approaches to enhancing health span in the elderly population(ref).” Also, I have written before on how telomerase expression can promote the differentiation of stem cells independently of telomere extension.  See, for example, the post Extra-telomeric benefits of telomerase.     

Speculations on preventing or significantly delaying immunosenescence 

I speculate here on possible future approaches that could conceivably prevent immunosenescence completely, or at least delay its onset for a very long time.  I need stress that right now exactly how to go about these procedures is unknown

• One approach would be focus further on the stem and progenitor differentiation function and determine whether there may be ways to modify Notch and possibly mTOR and other pathway signaling to keep open the differentiation pathway leading from hematopoietic stem cells to mature T cells.   Hints about how to go about doing this are buried in some of the research studies referenced above.
• Another approach would involve changing epigenomic markers within T cells so as selectively to erase recordings of possibly irrelevant antigens from the far past.  I have no idea of how this could specifically be done but the current intense research focus on epigenomics and the other “omics” might show the way(ref)(ref). We do know how to erase epigenomic memory completely in cells(ref).  The challenge is how to erase it part way in a controlled manner.
• Another approach would be to focus on the health of pools of  hematopoietic stem cells and possibly employ a form of induced pluripotent stem cell (ref)(ref) technology to prime the pump at the head of the stem cell supply chain by creating a continuing new supply of healthy hematopoietic stem cells.  In other words, we probably need to tackle the problem upstream of where most current research focus is.  That is how I think aging needs to be addressed.

Time will tell if any of these approaches will make sense.

I am working on a mini-treatise on immunosenescence for this blog – age related decline in immune functioning.  This is a very important topic insofar as longevity is concerned.  It is a knotty topic with a lot to say about it.  So it may take me a day or two more before the next heavy-duty post appears here.  In the meanwhile I am passing on an item my wife sent me proving that we are hard-wired in ways we do not know.  Here is what I got via a chain e-mail:

HOW SMART IS YOUR RIGHT FOOT? You have to try this please,  it takes 2 seconds. I could not believe this!  It is from an orthopedic surgeon............. This will confuse your mind and you will keep trying over and over again to see if you can out smart your foot, but, you can't.  It is pre-programmed in your brain!1. While sitting at your desk in front of your computer, lift your right
foot off the floor and make clockwise circles.  2. Now, while doing this, draw the number '6' in the air with your right hand. Your foot will change direction. I told you so! And there's nothing you can do about it! You and I both know how
stupid it is, but before the day is done you are going to try it again, if you've not already done so.

Makes me wonder about what other response patterns are hard-wired in my body.

Very recently, Senator Ted Kennedy died from Glioblastoma multiforme (GBM), possibly the deadliest known cancer(ref).  I lost a dear friend to it just three years ago.  This post looks at some of the GBM research over the last five years.  It touches on the potential role of GBM stem cells and a potential key therapeutic role for one of the supplements many of us take – curcumin.

GBM is an extremely aggressive brain cancer involving glial cells in the brain and kills just about everyone who gets it. “Median survival with standard-of-care radiation and chemotherapy with temozolomide is 15 months. Median survival without treatment is 4 1/2 months(ref).”  Patients rarely last more than two years from time of diagnosis.  When it comes to glioblastoma, a treatment that adds just 3-4 months to a patient’s life is thought to be worth considering.

The hopelessness of the disease is summarized in the lead paragraph of the monograph entitled State-of-the-art Therapy for Glioblastoma Multiforme: “The treatment of patients with glioblastoma multiforme (GBM) is conventionally considered to be a palliative venture with no hope of cure. Traditionally, patients are treated with maximal surgical resection based on the premise that, although surgery is not a curative procedure, a major resection provides for a longer survival and better quality of life.  Radiotherapy increases the duration of survival, but again is not a curative intervention(ref).”  

When your friend or relative learns he has GBM, he may have only six months more to live. GBMs can come on very suddenly without warning and can be of two main types known as Primary and Secondary.  “Primary glioblastoma multiforme accounts for the vast majority of cases (60%) in adults older than 50 years. These tumors manifest de novo (i.e., without clinical or histopathologic evidence of a preexisting, less-malignant precursor lesion), presenting after a short clinical history, usually less than 3 months.” – “Secondary glioblastoma multiformes (40%) typically develop in younger patients (<45 y) through malignant progression from a low-grade astrocytoma (WHO grade II) or anaplastic astrocytoma (WHO grade III). The time required for this progression varies considerably, ranging from less than 1 year to more than 10 years, with a mean interval of 4-5 years. Increasing evidence indicates that primary and secondary glioblastomas constitute distinct disease entities that evolve through different genetic pathways, affect patients at different ages, and differ in response to some of the present therapies(ref).” 

GBM is thought to arise from a unique combination of genetic mutations such as are described in this publication.  As written in 2000: “Because most patients with GBMs die of their disease in less than a year and essentially none has long-term survival, these tumors have drawn significant attention; however, they have evaded increasingly cleaver and intricate attempts at therapy over the last half-century(ref).”  There has been a stream of news reports in the science press on research related to new treatments for glioblastoma.  Here is a selection of headlines and lead paragraphs of reports appearing in Science Daily.

Vorinostat Shows Anti-cancer Activity In Recurrent Gliomas:  ScienceDaily (June 5, 2007) — “North Central Cancer Treatment Group researchers, based at Mayo Clinic in Rochester, Minn., report that a novel application of the drug vorinostat shows activity in patients with recurrent glioblastoma multiforme. These findings were presented today at the American Society of Clinical Oncology Annual Meeting by Eva Galanis, M.D., a Mayo Clinic oncologist and lead investigator of the study.”  (ref)

Mayo Clinic Researchers Develop New Treatment For Incurable Recurring Form Of Adult Brain Cancer: ScienceDaily (May 17, 2005) — ROCHESTER, Minn. – “A study led by Mayo Clinic researchers and conducted by the North Central Cancer Treatment Group (NCCTG) reports that a new “smart” drug treatment for an incurable form of recurrent brain cancer slowed tumor growth in more than one-third of the 65 adult patients who tried it. The same research team also developed a screening technique to help predict which patients will respond best to this treatment.”  (ref)

New Treatment Suitable For All Patients With Least Treatable Brain Tumors, Study Suggests: ScienceDaily (Jan. 5, 2008) — New research at Wake Forest University Baptist Medical Center suggests that a three-drug cocktail may one day improve outcomes in patients with glioblastoma multiforme (GBM), a type of brain tumor with a dismal prognosis. Two of the drug candidates have been developed, and the team is working on the third — all targeted to kill or impair cancer cells and spare healthy brain. (ref)

Why Don’t Brain Tumors Respond To Medication?  ScienceDaily (Sep. 2, 2009) — “Malignant brain tumors often fail to respond to promising new medication. Researchers in Heidelberg have discovered a mechanism and a tumor marker for the development of this resistance. A “death receptor” can possibly provide information as to how great the chances of success are for chemotherapy. At the same time, it offers a new approach for promising brain tumor therapy.” (ref)

Research Suggests Molecular Approaches To Brain Tumor Treatment: ScienceDaily (May 10, 2005) — WINSTON-SALEM, N.C. – “Researchers at Wake Forest University Baptist Medical Center have found promising new molecular targets and treatment approaches for some of the most malignant brain tumors.  Results of three separate studies were presented at the World Federation of NeuroOncology meeting and the European Association for NeuroOncology meeting, both in Edinburgh, Scotland, on May 6 and 7. The research involved glioblastoma multiforme, the most common form of brain tumor and the least curable of all human cancers. — The first study identified a protein that seems to control the malignant features of brain tumor cells, suggesting a new treatment target for anti-cancer drugs. Researchers found that a little-known protein called Fra-1 was effective in controlling vascular endothelial growth factor D, a factor that promotes the growth of new blood vessels in most malignant brain tumors. “This protein seems to be important in how tumors grow and how they may spread to healthy tissue,” said Waldemar Debinski, M.D., Ph.D., director of the Brain Tumor Center of Excellence at Wake Forest University Baptist Medical Center. “It is a very powerful biological factor and may be an attractive target for anti-cancer therapy.” — The second study builds in earlier research by Debinski and colleagues that found that glioblastoma cells have a particular type of receptor for interleukin 13 (IL-13), a naturally occurring protein that regulates the immune system in the body. Normal cells do not have these same receptors. IL-13 is a very attractive target for molecular anti-brain tumor therapies and two clinical trials are currently ongoing. The new study examined the role of proteins called cytokines in augmenting the amount of IL-13 receptor expressed by tumor cells. The use of these cytokines may improve treatment of glioblastoma cells by increasing the levels of IL-13 receptor in brain tumors and thus making them more accessible to drugs targeting the receptor. — The third research study focused on the search for novel specific molecular markers or targets in brain tumors. EphA2, a cell membrane-anchored protein-receptor, was shown to be uniformly overexpressed in malignant brain tumors, but not in normal brain tissue. “EphA2 represents a novel target for the development of molecular therapeutics for the imaging and treatment of patients with glioblastoma,” said Debinski.” (ref)

All of the above may indicate research progress against GBM.  My impression is that much of the research seems to be concentrated on finding means to slow the progress of GBM down.  This link describes a clinical trial of an immunotherapy “that targets the tumor specific molecule called EGFRvIII, a functional variant of the epidermal growth factor receptor (EGFR), a protein that has been well validated as a target for cancer therapy.” – “Previous small-scale trials indicated the approach may succeed with a limited objective. “The results of these studies have demonstrated a significant increase in the time to disease progression and overall survival relative to appropriately matched historical controls(ref).”

Glioblastoma stem cells

Previously in this blog, I have touched on research pointing to the importance of cancer stem cells in brain cancers, such as in the post On Cancer Stem Cells. In more detail, you can check out these Science Daily stories:

Cancer Stem Cells Spur Glioma Angiogenesis, Could Hold Key To Brain Tumor Therapy (ref)  “Stem cell-like glioma cancer cells that share many characteristics with normal stem cells propel the lethal growth of brain cancers by promoting tumor blood vessel formation, and may hold the key to treating these deadly cancers—“

Glioma: Origin Of Brain Tumor Discovered (ref)  “Glioma is the most common and most serious form of brain tumors that affect adults. It has not yet been determined which specific type of cell in the brain is the source of the tumor, but now a research team at Uppsala University can show that glioma can start from immature support cells.   — In recent years it has been discussed more and more often that it is neural stem cells in the brain that are transmuted into cancer cells and can then develop into glioma. “But our results show that immature support cells can function as the source cells for the tumor. We can thus establish that it does not have to be stem cells that cause glioma,”

Curcumin for glioblastoma

Back in the post From four-pound hammer to smart molecules – on cancer treatments, I touched on how an old supplement friend curcumin appears to be very effective in leading GBM cells to commit apoptosis. This has led researchers to suggest investigating whether curcumin could be used as a therapeutic approach.  You can check out these publications

Curcumin suppressed anti-apoptotic signals and activated cysteine proteases for apoptosis in human malignant glioblastoma U87MG cells (ref) “Results show that CCM is an effective therapeutic agent for suppression of anti-apoptotic factors and activation of calpain and caspase proteolytic cascades for apoptosis in human malignant glioblastoma cells.”

Curcumin activated both receptor-mediated and mitochondria-mediated proteolytic pathways for apoptosis in human glioblastoma T98G cells (ref) “Our results strongly suggest that CCM induced both receptor-mediated and mitochondria-mediated proteolytic mechanisms for induction of apoptosis in T98G cells.”

p21 Waf1/Cip1 expression by curcumin in U-87MG human glioma cells: role of early growth response-1 expression. (ref) “Curcumin, a natural compound, is a well-known chemopreventive agent with potent anticarcinogenic activity in a wide variety of tumor cells. Curcumin inhibits cancer cell proliferation in part by suppressing cyclin D1 and inducing expression of the cyclin-dependent kinase inhibitor p21(Waf1/Cip1).”

Curcumin suppresses growth and chemoresistance of human glioblastoma cells via AP-1 and NFkappaB transcription factors. (ref) “Curcumin reduced cell survival in a p53- and caspase-independent manner, an effect correlated with the inhibition of AP-1 and NFkappaB signaling pathways via prevention of constitutive JNK and Akt activation. Curcumin-sensitized glioma cells to several clinically utilized chemotherapeutic agents (cisplatin, etoposide, camptothecin, and doxorubicin) and radiation, effects correlated with reduced expression of bcl-2 and IAP family members as well as DNA repair enzymes (MGMT, DNA-PK, Ku70, Ku80, and ERCC-1). These findings support a role for curcumin as an adjunct to traditional chemotherapy and radiation in the treatment of brain cancer.”

Differential solubility of curcuminoids in serum and albumin solutions: implications for analytical and therapeutic applications. (ref) “CONCLUSION: These results suggest the possibility of alternative therapeutic approaches by injection or infusion of relatively small amounts of curcuminoid-enriched serum.”

How does curcumin work to lead the glioblastoma cells to commit suicide?  Collectively, studying the following reports suggests that curcumin works by multiple channels including 1. regulating the p21 apoptosis-inhibitor gene in the tumors, and 2 inducing JNK signaling which activates MDA-7 resulting in inhibition of AP-1, AKT and NF-kappaB pathways necessary for critical gene expression. 

Curcumin inhibits proliferation, invasion, angiogenesis and metastasis of different cancers through interaction with multiple cell signaling proteins (ref) “Because most cancers are caused by dysregulation of as many as 500 different genes, agents that target multiple gene products are needed for prevention and treatment of cancer. Curcumin, a yellow coloring agent in turmeric, has been shown to interact with a wide variety of proteins and modify their expression and activity. These include inflammatory cytokines and enzymes, transcription factors, and gene products linked with cell survival, proliferation, invasion, and angiogenesis. Curcumin has been found to inhibit the proliferation of various tumor cells in culture, prevents carcinogen-induced cancers in rodents, and inhibits the growth of human tumors in xenotransplant or orthotransplant animal models either alone or in combination with chemotherapeutic agents or radiation. Several phase I and phase II clinical trials indicate that curcumin is quite safe and may exhibit therapeutic efficacy.

p21 Waf1/Cip1 expression by curcumin in U-87MG human glioma cells: role of early growth response-1 expression (ref) “Curcumin inhibits cancer cell proliferation in part by suppressing cyclin D1 and inducing expression of the cyclin-dependent kinase inhibitor p21(Waf1/Cip1).  — Here, we report that transcription of the p21(Waf1/Cip1) gene is activated by early growth response-1 (Egr-1) independently of p53 in response to curcumin treatment in U-87MG human glioblastoma cells.”

Activation of multiple molecular mechanisms for apoptosis in human malignant glioblastoma T98G and U87MG cells treated with sulforaphane (ref)MDA-7 regulates cell growth and radiosensitivity in vitro of primary (non-established) human glioma cells. (ref) “Collectively, our findings demonstrate that MDA-7 reduces proliferation and enhances the radiosensitivity of nonestablished human GBM cells in vitro, and when grown in 3 dimensions, and that sensitization occurs independently of basal EGFR/ERK1/2/AKT activity or the functions of PTEN and p53.”

Regulation of GST-MDA-7 toxicity in human glioblastoma cells by ERBB1, ERK1/2, PI3K, and JNK1-3 pathway signaling (ref) “Our data argue that combined inhibition of ERK1/2 and AKT function, regardless of genetic background, promotes MDA-7 lethality in human primary human glioma cells via JNK1-3 signaling and is likely to represent a more ubiquitous approach to enhancing MDA-7 toxicity in this cell type than inhibition of ERBB1 function.”

Expression of the constitutively activated RelA/NF-kappaB in human astrocytic tumors and the in vitro implication in the regulation of urokinase-type plasminogen activator, migration, and invasion. (ref)

mda-7 (IL-24) Inhibits growth and enhances radiosensitivity of glioma cells in vitro via JNK signaling. (ref)  “Inhibition of JNK1/2, but not p38, signaling abolished the radiosensitizing properties of MDA-7. Inhibition of neither ERK1/2 nor PI3K signaling enhanced the anti-proliferative effects of Ad.mda-7, whereas combined inhibition of both pathways enhanced cell killing, suggesting that ERK and PI3K signaling can be protective against MDA-7 lethality.”

Inhibition of the c-Jun N-terminal kinase (JNK) signaling pathway by curcumin (ref)  “Curcumin, a dietary pigment in curry, suppresses tumor initiation and tumor promotion. Curcumin is also a potent inhibitor for AP-1 and NF- B activation. In this report, we show that curcumin inhibits JNK activation by various agonists — Taken together, the inhibition of the MEKK1-JNK pathway reveals a possible mechanism of suppression of AP-1 and NF- B signaling by curcumin, and may explain the potent anti-inflammatory and anti-carcinogenic effects of this chemical.”

PERK-dependent regulation of MDA-7/IL-24-induced autophagy in primary human glioma cells. (ref) “Our data demonstrate that GST-MDA-7 induces an ER stress response that, via the induction of autophagy, is causal in the activation of pro-apoptotic pathways that converge on the mitochondrion and ultimately culminate in decreased glioma cell survival.”

Curcumin is found on spice shelves everywhere and is great in Indian curries.  It is very homespun stuff.  Its bimolecular actions against “incurable” glioblastoma, on the other hand, appear to be very cutting edge.  Curcumin might, just might, provide a powerful weapon in the battle against glioblastoma.   

Please note the Medical Disclaimer for this blog.

This post is concerned with recent research focused on the impact of the FOXO (Forkhead) transcriptions factors on the health of hematopoietic stem cell pools in human bodies.  As regular readers of this blog may know, I see stem cells as playing key roles in the aging process and I have recently added a new theory of aging to my Anti-Aging Firewalls Treatise, the Stem Cell Supply Chain Breakdown theory.  In this blog post I briefly discuss how the FOXO genes have been seen to be related to longevity, review a few research findings relating FOXOs to stem cells, and speculate on what these could mean for resveratrol takers.

There are hundreds of publications related to the human FOXO transcription factors FKHR (FOXO1), FKHR-L1 (FOXO3a) and AFX (FOXO4).  The molecular activities of these factors are fascinating but most of them are too complex to be discussed here.  I mention only a few key findings:

·        “FOXO transcription factors are at the interface of crucial cellular processes, orchestrating programs of gene expression that regulate apoptosis, cell-cycle progression, and oxidative stress(ref).”  They play key roles in DNA repair, energy homeostasis, glucose metabolism, reactive oxygen species detoxification, cell cycle arrest, and cell death.

·        It has been suspected for some time that the FOXO factors are implicated in the human aging process. “A homologue of FOXO1A, daf-16, has been associated with ageing in roundworms [ref], and overexpression of another homologue, dFOXO, in adult fat body of fruit flies increased longevity in females [ref](ref).”  In fact, this FOXO signaling pathway was first identified in the nematode worm Caenorhabditis elegans where it was noted for its longevity impacts.

·        A polymorphism of the FOXO3 gene is definitely associated with longevity in humans. It is found in most centenarians across a variety of ethnic groups around the world(ref)(ref)(ref).

·        “Consistent with the notion that stress resistance is highly coupled with lifespan extension, activation of FOXO transcription factors in worms and flies increases longevity. Emerging evidence also suggests that FOXO factors play a tumor suppressor role in a variety of cancers. Thus, FOXO proteins translate environmental stimuli into changes in gene expression programs that may coordinate organismal longevity and tumor suppression(ref).

·         The sirtuin SIRT1 regulates the FOXO genes. “The Sir2 deacetylase modulates organismal life-span in various species. However, the molecular mechanisms by which Sir2 increases longevity are largely unknown. We show that in mammalian cells, the Sir2 homolog SIRT1 appears to control the cellular response to stress by regulating the FOXO family of Forkhead transcription factors, a family of proteins that function as sensors of the insulin signaling pathway and as regulators of organismal longevity. SIRT1 and the FOXO transcription factor FOXO3 formed a complex in cells in response to oxidative stress, and SIRT1 deacetylated FOXO3 in vitro and within cells. SIRT1 had a dual effect on FOXO3 function: SIRT1 increased FOXO3’s ability to induce cell cycle arrest and resistance to oxidative stress but inhibited FOXO3’s ability to induce cell death(ref).”

·        Resveratrol, used by some as an anti-aging supplement, activates SIRT1 and its longevity impacts are thought to be due to the actions of the FOXO factors as impacted by SIRT1(ref).

I have mentioned most of these facts before.  They are listed here mainly for background.

The research relating FOXO to stem cells is encapsulated by the title of this research publication: “Foxo3a Is Essential for Maintenance of the Hematopoietic Stem Cell Pool.” See also “FoxO Transcription Factors and Stem Cell Homeostasis: Insights from the Hematopoietic System.”  “Hematopoietic development is regulated by a dynamic balance between HSC (hematopoietic stem cell) self-renewal and differentiation to mature effector cells. The balance between self-renewal and differentiation is of critical importance: too little self-renewal or too much differentiation may jeopardize the ability to sustain hematopoiesis throughout life, whereas excessive self-renewal and/or aberrant differentiation may result in leukemogenesis. The regulation of HSC self-renewal is not fully understood, but recent studies have underscored the importance of cell cycle, apoptosis, and oxidative stress response in HSC homeostasis. Recent data indicate that FoxO family members play a critical role in these physiologic processes in the HSC compartment and thereby regulate maintenance and integrity of HSCs(ref).”

Maintenance of the stem cell pools health can be a very critical matter.  “The researchers at Brigham and Women’s found that mice engineered to lack genes for the FoxO1, FoxO3, and FoxO4 molecules had serious blood abnormalities. Without the FoxO gene-regulating molecules, the rodents’ blood stem cells — master cells that give birth to working blood cells while also renewing themselves ¬– divided too fast and “burned out,” said Gary Gilliland, MD, PhD, who is senior co-author of the two papers with Ronald DePinho, MD, of Dana-Farber.  “If we didn’t have these FoxO proteins to keep stem cells healthy, it is likely that we wouldn’t be able to live for more than a few months,” said Gilliland(ref).”

There may be a major implication regarding the action of resveratrol.  It could be that some or all of resveratrol’s reported life-extending benefits are due to enhancing the proliferative and differentiating capabilities of pools of stem cells via activation of SIRT1 and FOXO3A signaling.  It is difficult to say this for sure since FOXO also plays key roles in defense against cancers and in assuring antioxidant defense.  There is growing reason to see aging in terms of Stem Cell Supply Chain Breakdown.

I like this anti-aging medicine so much that I sometimes feel guilty when I eat it. There are some 380 distinct known chemicals in chocolate and many of those are bioactive.  However, the main beneficial ingredient in chocolate is the flavonoid Epicatechin.  “Cocoa, the major ingredient of dark chocolate, contains relatively high amounts of epicatechin and has been found to have nearly twice the antioxidant content of red wine and up to three times that of green tea in in-vitro tests(ref)(ref).”   Epicatechin is also found in other foods including tea and grapes.   Some research findings re chocolate:

• Promotes cardiovascular health:  From a 2006 report Chocolate and prevention of cardiovascular disease: a systematic review:  “The body of short-term randomized feeding trials suggests cocoa and chocolate may exert beneficial effects on cardiovascular risk via effects on lowering blood pressure, anti-inflammation, anti-platelet function, higher HDL, decreased LDL oxidation.” “–flavonoids are likely protective against CHD (cardiovascular heart disease) mortality. The highest priority now is to conduct larger randomized trials to definitively investigate the impact of chocolate consumption on long-term cardiovascular outcomes(ref).”  Several other research publications reinforce the same viewpoint.  For example, a 2008 review study report states “While flavonoids are ubiquitous in plants, cocoa can be particularly rich in a sub-class of flavonoids known as flavanols. A number of human dietary intervention trials with flavanol-containing cocoa products have demonstrated improvements in endothelial and platelet function, as well as blood pressure. These studies provide direct evidence for the potential cardiovascular benefits of flavanol-containing foods and help to substantiate the epidemiological data.– Together the results of these human dietary intervention trials provide scientific evidence of the vascular effects of cocoa flavanols and suggest that the regular consumption of cocoa products containing flavanols may reduce risk of CVD(ref).”
• Cuts death risk for coronary heart disease patients who have had a heart attack:  A study reported a couple of weeks ago, was based on following 1,169 non-diabetic patients hospitalized with a confirmed first acute myocardial infarction (AMI) between 1992 and 1994 in Sweden as part of the Stockholm Heart Epidemiology Program.  Patients were followed for 8 years and reported on chocolate consumption as part of a standard questionnaire.  “Chocolate consumption had a strong inverse association with cardiac mortality. [More chocolate, less mortality.” —  “Chocolate consumption was associated with lower cardiac mortality in a dose dependent manner in patients free of diabetes surviving their first AMI(ref).”

·        Helps prevent age-related dementia: Back in the post Warding off Alzheimer’s Disease and things in my diet, I quoted about my daily chocolate  snack: “Oxidative stress induced by reactive oxygen species has been strongly associated with the pathogenesis of neurodegenerative disorders, including Alzheimer’s disease.  In this study, we investigated the possible protective effects of a cocoa procyanidin fraction (CPF) and procyanidin B2 (epicatechin-(4beta-8)-epicatechin) – a major polyphenol in cocoa – against apoptosis of PC12 rat pheochromocytoma (PC12) cells induced by hydrogen peroxide.  — These results suggest that the protective effects of CPF and procyanidin B2 against H(2)O(2)-induced apoptosis involve inhibiting the downregulation of Bcl-X(L) and Bcl-2 expression through blocking the activation of JNK and p38 MAPK(ref).” 

·        Is neuroprotective and modulates brain functioning: The epicatechin in chocolate like other flavonoids is neuroprotective.  “Flavonoids exert a multiplicity of neuroprotective actions within the brain, including a potential to protect neurons against injury induced by neurotoxins, an ability to suppress neuroinflammation, and the potential to promote memory, learning and cognitive function(ref).” Another study report states “dietary flavonoids might have potential as protective agents against neuronal apoptosis through selective actions within stress-activated cellular responses, including protein kinase signalling cascades(ref).”  And yet-another report states “Emerging evidence suggests that dietary phytochemicals, in particular flavonoids, may exert beneficial effects on the central nervous system by protecting neurons against stress-induced injury, by suppressing neuroinflammation and by improving cognitive function(ref).”   I often experience a rush of good feeling and what seems to be an ability to think more clearly after a chocolate fix,  but usually attribute that to being a sugar rush or perhaps a quirk of my imagination.  Quite possibly that effect is biochemically driven by the chocolate itself and real.

·        Reverses vascular dysfunction in diabetes:  This publication reports on two studies looking at the feasibility and efficacy of dietary intervention based on daily intake of flavanol-containing cocoa for improving vascular function in diabetic patients.  The feasibility study involved 10 diabetic patients and the follow-up efficacy study 41 medicated diabetic patients. Both studies were double-masked, randomized, controlled trials.  The study found sustained benefits and concludes “Diets rich in flavanols reverse vascular dysfunction in diabetes, highlighting therapeutic potentials in cardiovascular disease(ref).”

·        Lowers blood pressure in overweight adults: The conclusions of a randomized, placebo-controlled, single-blind crossover trial of 45 healthy adults state “The acute ingestion of both solid dark chocolate and liquid cocoa improved endothelial function and lowered blood pressure in overweight adults. Sugar content may attenuate these effects, and sugar-free preparations may augment them(ref).” 

·        Lowers blood pressure in normal adults: Another study Effects of low habitual cocoa intake on blood pressure and bioactive nitric oxide: a randomized controlled trial concludes. “Data in this relatively small sample (44 adults aged 56 through 73 years) of otherwise healthy individuals with above-optimal BP (blood pressure) indicate that inclusion of small amounts of polyphenol-rich dark chocolate as part of a usual diet efficiently reduced BP and improved formation of vasodilative nitric oxide(ref).”  See also Effect of dark chocolate on arterial function in healthy individuals: cocoa instead of ambrosia? and Effect of dark chocolate on arterial function in healthy individuals.

·        May help prevent artery hardening due to smoking: “Researchers compared the effects of dark (74% cocoa solids) and white chocolate on the smoothness of arterial blood flow in 20 male smokers.” – “After two hours, ultrasound scans revealed that dark chocolate significantly improved the smoothness of arterial flow, an effect which lasted for eight hours. Blood sample analysis also showed that dark chocolate almost halved platelet activity. Antioxidant levels rose sharply after two hours.” – “Only a small daily treat of dark chocolate may substantially increase the amount of antioxidant intake and beneficially affect vascular health,” conclude the authors(ref).”

Other interesting findings related to chocolate are:

·        Brain awareness benefits of chocolate consumption are visible in MRI scans: “The present study employed functional magnetic resonance imaging based on blood oxygenation level-dependent (BOLD) contrast to explore the effect of flavanols on the human brain. Magnetic resonance imaging was used to measure BOLD responses to a cognitive task in 16 healthy young subjects. The data presented show an increase in the BOLD signal intensity in response to a cognitive task following ingestion of flavanol-rich cocoa (5 days of 150 mg of cocoa flavanols). This may arise either as a result of altered neuronal activity, or a change in vascular responsiveness, or both –(ref).”

·        Benefits of chocolate consumption may be greater for older people:  This publication reports study “of blood pressure and peripheral arterial responses to several days of cocoa in 15 young (< 50 years) and 19 older (> 50) healthy subjects.” Conclusions: Flavanol-rich cocoa enhanced several measures of endothelial function to a greater degree among older than younger healthy subjects. Our data suggest that the NO-dependent vascular effects of flavanol-rich cocoa may be greater among older people, in whom endothelial function is more disturbed(ref).”  Also, in another report “Observations point to a favorable response among the older. Together with peripheral vascular disease, cerebrovascular disease is responsible for significant mortality with advancing age. An association of decreased cerebral perfusion with dementia has been recently highlighted. The prospect of increasing cerebral perfusion with cocoa flavanols is extremely promising(ref).”

·        Endothelial and cardiovascular benefits of cocoa consumption are due in some large measure to induction of nitric oxide vasodilation: Several studies make this point; for example: “ Therefore, ingested flavonoids may reverse endothelial dysfunction through enhancement of NO bioactivity(ref).” As stated in another research report, “In healthy humans, flavanol-rich cocoa induced vasodilation via activation of the nitric oxide system, providing a plausible mechanism for the protection that flavanol-rich foods induce against coronary events(ref).”  This is the sex aspect of consuming chocolate.  Inducing vasodialation via activation of the nitric oxide system is what the erectile dysfunction drugs Viagra (Sildenafil), Cialis (Tadalafil), and Levitra (Vardenafil) do in their own somewhat-similar ways(ref).         

On the whole is eating chocolate good for you?  Of course it depends on the chocolate product you eat.  These products can vary widely in both polyphenol/flavonoid, fat and sugar content(ref)(ref).  And in some cases the health hazards of the sugar and fat can outweigh the health benefits of the chocolate flavonoid content.  However,  the large-population studies mentioned above are based on consumption of commercial chocolate products.  Personally, I have been eating 72% cocoa solids Belgian Chocolate available in a big red-wrapped bar from Trader Joe’s and am now increasingly eating enhanced-flavonoid chocolate products that are now becoming commercially available.  Preparing to put this blog post online, I have just rewarded myself with two squares from a big red bar.

Several studies have shown that variations in the FTO gene are associated with increased fatness and obesity in humans as well as, of course, mice and rats.  The gene is an ancient one.  “The FTO gene is well conserved and found in a single copy in vertebrate species including fish and chicken, suggesting that the ancestor of this gene was present 450 million years ago(ref).”  “Three independent studies have shown that variation in the fat mass and obesity-associated (FTO) gene associates with BMI and obesity(ref).”  In particular, the FTO rs9939609 gene polymorphism seems to be correlated with obesity, general morbidity and with type 2 diabetes(ref)(ref)(ref)(ref).  In a study “of a population of 362,200 Danish young men, examined for military service between 1943 and 1977, all obese (BMI>or=31.0 kg/m(2)) and a random 1% sample of the others were identified.  In 1992-94, at an average age of 46 years” – “In total 205 men died. Mortality was 42% lower (p = 0.001) with the TT genotype than in A-allele  (the FTO rs9939609 gene polymorphism) carriers. This phenomenon was observed in both the obese and the randomly sampled cohort when analyzed separately(ref).”  

Here are some things being discovered about FTO gene: The gene’s relationship to obesity apparently has more to do with food intake than metabolism.  “The accumulated data across seven independent studies therefore clearly implicates the FTO gene in humans as having a direct impact on food intake but no effect on energy expenditure(ref)”.   Low physical activity accentuates the effect of the FTO rs9939609 polymorphism on body fat accumulation.  “The association between FTO SNP rs9939609 and obesity risk may decline at older age(ref).” “The association of the examined FTO SNP to general fatness throughout the range of fatness was confirmed, and this association explains the relation between the SNP and body fat distribution and decreased insulin sensitivity and HDL-cholesterol(ref).” “Our results show: (1) A strong association between rs9939609 SNP of the FTO gene variant and obesity in Spanish morbidly obese adult patients (ref).” “Independent of fatness, the A-allele of the FTO SNP appears to increase mortality of a magnitude similar to smoking, but without a particular underlying disease pattern barring an increase in the risk of diseases of the nervous system(ref).” A number of other interesting tidbits of information on the FTO gene can be found in the Wikipedia article on it.

Mouse weight-loss clinic

Because of the intron nature of the obesity-associated SNPs, it has been “unclear whether changes in FTO expression or splicing are the cause of obesity or if regulatory elements within intron 1 influence upstream or downstream genes(ref).”  An August 2009 mouse-model study report points to the FTO gene itself.  “We show that a dominant point mutation in the mouse FTO gene results in reduced fat mass, increased energy expenditure, and unchanged physical activity. Exposure to a high-fat diet enhances lean mass and lowers fat mass relative to control mice. Biochemical studies suggest the mutation occurs in a structurally novel domain and modifies FTO function, possibly by altering its dimerisation state. Gene expression profiling revealed increased expression of some fat and carbohydrate metabolism genes and an improved inflammatory profile in white adipose tissue of mutant mice. These data provide direct functional evidence that FTO is a causal gene underlying obesity(ref).”   

Sounds like mutating FTO could possibly turn out to be weight-loss approach for humans.  It worked for the mice with no reported effects except that they were skinnier and lighter.  Clearly human research is needed before this approach hits the weight-loss clinics, even the ones in Romania.

Suppose there were a place in the world where there is a concentration of research laboratories busy working on antibiotics, cures for diseases, means for neutralizing environmental toxins and other molecular approaches that make for longevity.  Suppose further that these laboratories have been doing such work for a long time and have already discovered hundreds if not thousands of molecular-based longevity solutions – solutions unknown in our mainline science.  Suppose further that means for efficient manufacturing of these molecular solutions have also been worked out in these laboratories and that the solutions have already been tested and shown to work in various species.  Finally, suppose that there are literally billions of such laboratories concentrated in many places in the world. 

All this exists.  The laboratories are plants, insects and fauna.  The solution-discovery process is called evolution, rainforests are among the places where the biomolecular solution process takes place, and the laboratories have been at it for hundreds of millions of years.  This post is about disovering health and longevity solutions by studying such laboratories.

To begin, I point out a few facts about rainforests and that many of our important existing drugs are based on rainforest plants.  From Rainforest Facts” “Currently, 121 prescription drugs currently sold worldwide come from plant-derived sources. And while 25% of Western pharmaceuticals are derived from rainforest ingredients, less than 1% of these tropical trees and plants have been tested by scientists.” “More than half of the world’s estimated 10 million species of plants, animals and insects live in the tropical rainforests. One-fifth of the world’s fresh water is in the Amazon Basin.” ‘One hectare (2.47 acres) may contain over 750 types of trees and 1500 species of higher plants.”  “Nearly half of the world’s species of plants, animals and microorganisms will be destroyed or severely threatened over the next quarter century due to rainforest deforestation.”

Among the important existing drugs derived from rain forest plants are Neostigmine used for glaucoma, Quinine for treating malaria and inflammatory diseases, Cocaine-derived anesthetics, Turbocuarine-based muscle relaxants, Vincristine and Vinblastine used to treat pediatric leukemia and  Hogkin’s disease, and Cortisone is used for many purposes and is the active ingredient in birth control pills(ref).

The process of drug-discovery based on studying rainforest plants is a very different than the conventional drug-discovery approaches based on massive screening of compounds, improving on existing drugs or taking advantage of unique molecular pathways.  Conventional drug and biotech companies may be at a disadvantage for such rainforest discovery compared to new eco-discovery companies.  A place to start can be traditional cures used by indigenous people and known to shamans. 

Shaman Pharmaceuticals is a San Francisco company concerned with: Integrating Indigenous Knowledge, Tropical Medicinal Plants, Medicine, Modern Science and Reciprocity into a Novel Drug Discovery Approach.  “Shaman Pharmaceuticals, Inc. is a South San Francisco-based pharmaceutical company that focuses on isolating bioactive compounds from tropical plants that have a history of medicinal use. Shaman is working to promote the conservation of tropical forests and bridge the gap between the biomedical needs of both indigenous cultures and the rest of the global population. Eschewing the mass screening approach typically done by many pharmaceutical companies, Shaman has pioneered a novel approach to drug discovery, integrating traditional plant natural products chemistry, the science of ethnobotany, medicine, and medicinal chemistry while maintaining a commitment of reciprocity to the indigenous cultures.”  Shaman Pharmaceutical’s operations began in 1990. Utilizing the ethnobotanical/ethnomedical approach to collecting tropical medicinal plant species, Shaman has been successful in bringing two products into clinical trials within 24 months of that time. This focused approach  is currently being used in Shaman’s antidiabetic discovery program. Since the inception of the diabetes program two years ago, Shaman has discovered multiple new chemical leads from plant sources and, to date, patents have been filed on five of them. Each of these chemical leads is currently undergoing preclinical evaluation(ref).“

Another eco-discovery company is the Australian company Ecobiotics(ref), which works in rainforests in Australia. “The researchers at EcoBiotics take a more encompassing approach to exploring the Australian rainforests than do companies who search for new compounds in South America’s rainforests. EcoBiotics’ cofounders, Victoria Gordon, Ph.D., and Paul Reddell, Ph.D., are chemical and forest ecologists who live and work at the company’s headquarters near Cairns in the Daintree Rainforest of northeastern Australia. Their research team experiences firsthand the seasonal variation in plants, insect assaults, and invasions of microorganisms.  In contrast, researchers at other drug companies generally visit rainforests for a few weeks, collect plant materials, and take them back to laboratories to analyze them for new chemicals, according to Delco. The holistic approach at EcoBiotics “is like watching a movie instead of looking at snapshots,” he adds.”  “Plants evolve amazingly complex and dynamic chemical systems to survive. For example, when attacked by pathogenic microbes, plants use pattern recognition receptors to identify their assailants and produce specific antibiotics to defend themselves. “Attract-or-repel interactions create novel chemicals,” says Delco, as plants respond to injury, climate change, or invaders in a limited space(ref).” 

When dealing with rainforest plants, strange clues can lead to new drug discoveries.  “The observation that rainforest marsupials spit out seeds after eating the fruit of a certain plant led to the company’s lead compound, EBC-46. Scientists at EcoBiotics learned that the unpalatable seeds contain an inflammatory agent that made the animals’ tongues swell. They isolated the active ingredient, a diterpene ester, which belongs to a new class of chemicals.  EBC-46 shows anticancer properties against basal and squamous cell carcinomas, melanoma, and head and neck tumors, Delco reports. The active ingredient in EBC-46 is easily purified from a ubiquitous plant species that can be quickly grown on plantations. The company is developing a GMP process to insure commercial quantities of the drug for future investigations.  EBC-46 is a protein kinase C regulator that initiates apoptosis of tumor cells and causes a local inflammatory reaction that recruits the body’s neutrophils to attack the tumor. When injected into incurable soft tissue sarcoids, nasopharangeal cancers, and oral malignant melanomas in horses, dogs, and sheep, EBC-46 destroyed the tumors and healing was evident in about two weeks, Delco reports. The positive animal results “don’t guarantee that EBC-46 will work in people,” he adds, “but it’s promising.” EcoBiotics plans to file an investigational new drug application for EBC-46 within a year (ref).”

Several other rainforest drug discovery programs are reported from time to time in the news.  See, for example, Malaria: New drug lead from Madagascar’s rainforests.  Often, those interested in rainforest drug discovery are also interested in preservation of the rainforest eco-environments.  See Drug Discovery Program Helps Save Rainforests, Too.  For more background on ethnobotanical rainforest drug discovery you can see this and this and this references.

Returning to the first point in this post, rain forest biological entities have been doing anti-aging and health research hundreds of millions of years.  It can serve us well to learn about and take advantage of that research before the rainforests are decimated. 

Finally, a quick observation comparing research-in-the-laboratory and research-by-evolution.  This is about antibiotics against infectious pathogens like staph and strep, a battle that has been going on for 70 years now.  In the history of this period many highly effective antibiotic drugs have been rendered ineffective by the evolutionary emergence of drug-resistant pathogen microbe strains, the latest including ultra drug resistant strains of MRSA (methicillin-resistant Staphylococcus aureus).  On the one hand we have thousands of researchers wearing white coats in gleaming laboratories spending long hours and hundreds of millions or billions of dollars researching ways to develop new drugs that will kill the drug-resistant strains.  Linezolid, one of the few drugs effective aginst some but not all strains of MRSA, costs about $100 per pill.  Meanwhile, the microbes themselves are quietly doing research by evolving, finding ways to survive by altering their molecular mechanisms despite whatever new drugs we throw at them.  Who is winning?  Recent evidence says the evolving microbes are pulling ahead.

The update of my online treatise  Anti-Aging Firewalls – The Science And Technology Of Longevity mentioned in my last blog post has been completed and I expect to return to generating regular almost-daily blog entries tomorrow.  I believe the new theory of aging described there, the Stem Cell Supply Chain Breakdown theory, is likely to acquire increasing importance as time progresses.  This theory is based on insight gained in the process of doing my research over the last year and is, insofar as I know, original.

I am taking a break from new blog postings for a few days and focusing on an update of my Anti-Aging Firewalls treatise, particularly on a comprehensive re-formulation of the 14^th theory of aging.  Where the theory was Decline in Adult Stem Cell Differentiation, now I am creating a more comprehensive version to be called the Stem Cell Supply Chain Breakdown theory.  This is a major intellectual effort on my part and involves integrating new material with much information I have learned over the last year and scattered through many blog entries.  Drawing on an unfolding torrent of new research relating to stem cells, this theory offers the possibility of becoming actionable.  It could well point to incredible new anti-aging interventions.  If you want hints of what will be included check out these past blog postings: An emerging new view of aging – the stem cell supply chain, Rebooting cells and longevity, and Treating genetic diseases with corrected induced pluripotent stem cells.  One of the reasons why I am excited by this new theory of aging is that it is original.  Unlike the other 13 theories, to my knowledge this new theory cannot be found in the existing literature although pieces of it are scattered everywhere.  Expect me to finish this task and be back blogging soon.

In my May 2009 blog post Longevity genes, mTOR and lifespan, I discussed the mTOR signaling pathway in mammals, its role in diseases, the relationship of mTOR to mitochondrial activity and how inhibiting mTOR could conceivably be a strategy for extending longevity.  In my Anti-Aging Firewalls treatise I subsequently added ABERRANT mTOR SIGNALLING as one of six additional candidate theories of aging to be considered. Recently-reported research studies concerned with mTOR link up important subjects I have previously discussed in this blog.  I focus here on two such sets of links.

mTOR and the hypoxic response

The mTOR pathway is illustrated in this diagram and is seen to be fairly complex even though the diagram leaves some important links out.  For example, as illustrated in the diagram a condition of hypoxia activates TSC1/TSC2 which inhibits Rheb which, with AKT, would normally activate mTOR.  The net result is that hypoxia inhibits the expression of mTOR, providing a neat linkup of two of the additional candidate theories of aging: the ABERRANT mTOR SIGNALLING theory already mentioned and the THE HYPOXIC RESPONSE theory.  See the blog posting Another longevity-related biochemical pathway – the hypoxic response.  The hypoxic response is known to lengthen life in primitive organisms and inhibition of mTOR is also thought to be a possible life-extending intervention.  The diagram shows a key way in which the two theories weave together. 

For those of you interested in delving further, here are links to a few of the research publications linking up hypoxia and mTOR: Regulation of mTOR function in response to hypoxia by REDD1 and the TSC1/TSC2 tumor suppressor complex, Hypoxia regulates TSC1/2-mTOR signaling and tumor suppression through REDD1-mediated 14-3-3 shuttling ,  and.  Hypoxia-induced energy stress inhibits the mTOR pathway by activating an AMPK/REDD1 signaling axis in head and neck squamous cell carcinoma. You may note that a lot of the current interest in controlling and limiting mTOR signaling is using this as an approach for suppressing tumors.

mTOR and the stem cell supply chain

In another important blog post An emerging new view of aging – the stem cell supply chain, I suggested a rather radical new view of aging and what can be done about it.  The essence if this view is: A.  the 210 different kinds of human cells can be separated into five categories: 1. pluripotent embryonic stem cells, 2. multipotent stem cells, 3. progenitor cells, 4. normal somatic cells and 5. senescent cells.  The list is in order of increasing cell-type specificity and decreasing potency to differentiate into other cell types.  Starting at conception and throughout life, all cells on this list except the senescent ones will selectively reproduce and differentiate into cells of types further down in the list.  Of course all the cells in an individual have the same genome but they acquire additional epigenomic markers as they differentiate.  I have referred to this process as the stem cell supply chain which must be kept in good working order if health is to be maintained.  B. Understanding aging requires understanding the stem cell supply chain – how and when stem and progenitor cells divide or differentiate and what makes them do that, and how this process can go wrong.  C.  Effective anti-aging interventions leading to extraordinary longevity will most likely require enhancing the operation of the stem cell supply chain.  It is no longer enough that anti-aging science is concerned with the life and death of cells.  It must also be concerned with the stem cell supply chain which provides the lifelong stream of cell renewal.

This April 2008 publication mTORC1 signaling governs hematopoietic stem cell quiescence relates mTOR signaling to the fate of an important pool of multipotent stem cells – hematopoietic stem cells (HCSs), the stem cells that give rise to the various blood cell types. “The stringent regulation of hematopoietic stem cell (HSC) quiescence versus cell cycle progression is essential for the preservation of a pool of long-term self-renewing cells and vital for sustaining an adequate supply of all blood lineages throughout life. Cell growth, the process that is mass increase, serves as a trigger for cell cycle progression and is regulated predominantly by mammalian target of rapamycin complex 1 (mTORC1) signaling. Emerging data from various mice models show deletion of several mTORC1 negative regulators, including PTEN, TSC1, PML and Fbxw7 result in similar HSC phenotypes characterized as HSC hyper-proliferation and subsequent exhaustion, and defective repopulating potential(ref).”  In other words, unless the negative regulators of mTORC1 are working well, the growth factors loosened by mTORC1 will cause the hematopoietic stem cells to reproduce like crazy exhausting the pool of these valuable cells – a major disruption in the stem cell supply chain.  

A second publication highlights the same point. “A balance between quiescence and proliferation of hematopoietic stem cells in interaction with the microenvironment is critical for sustaining long-term hematopoiesis and for protection against stress. — We demonstrated a pivotal role of two downstream effectors of the PI3K/Akt pathway, FoxO3a and mammalian target of rapamycin, as connectors in the SDF-1-/TGF–induced control of the cycling/quiescence switch and proposed a model integrating a dialogue between the two molecules in cell cycle progression(ref).”  Essentially the same point is made by a third study December 2008 publication mTORC1-dependent and -independent regulation of stem cell renewal, differentiation, and mobilization.  “TSC1 exists in a complex with TSC2 and functions primarily as a key negative regulator of mammalian target of rapamycin complex 1 (mTORC1) signaling and protein synthesis — Using hematopoietic stem cells (HSCs) as a model system, we demonstrate that somatic deletion of TSC1 produces striking stem cell and derivative effector cell phenotypes characterized by increased HSC cell cycling, mobilization, marked progressive depletion, defective long-term repopulating potential, and hematopoietic lineage developmental aberrations. On the mechanistic level, we further establish that TSC1 regulation of HSC quiescence and long-term repopulating potential and hematopoietic lineage development is mediated through mTORC1 signaling(ref).”

Effective mTORC1 negative regulation is essential for keeping the stem cell supply chain working well, at least insofar as hematopoietic stem cells are concerned.

There is a lot more that can be said about the subjects of this post and I expect I will cover additional key points as time progresses.  For example, the AKT and AMPK pathways are interesting and relate to matters discussed both in my treatise and in this blog as well as to mTOR signaling.   Perhaps I will take on one of these at some point.