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Contents

• A Coda to the C60 in Olive Oil Saga
• Towards Better Quantification of AGEs and Cross-Links in Human Tissues
• Inflammation in the Age-Related Thickening and Stiffening of Blood Vessel Walls
• Continuing to State the Obvious on Vulnerability to COVID-19 Due to Aging
• Strategies to Treat Vascular Aging
• Implicating TFAM in the Mitochondrial Dysfunction that Accelerates Immune Aging
• Transcriptomic Aging Clocks can be Improved by Combining Results from Different Tissues
• The Direction of Causation Between Fibrosis and Cellular Senescence
• A Loss of Transcriptional Coordination Observed in Cells from Older Individuals
• Using Oligodendrocyte Extracellular Vesicles to Induce Tolerance to Myelin as a Treatment for Multiple Sclerosis
• Reviewing the Development of Therapies to Target Cellular Senescence
• The Aging of the Gut Microbiome in Alzheimer's Disease
• Identifying Proteomic Profiles Associated with Aging
• Protrudin Gene Therapy Provokes Regrowth in Injured Optic Nerve Cells
• New Longevity Focused Venture Funds Continue to Emerge

A Coda to the C60 in Olive Oil Saga
https://www.fightaging.org/archives/2020/11/a-coda-to-the-c60-in-olive-oil-saga/

The matter of buckminsterfullerene (C60) in olive oil is an instructive example of how bad work can lead a field astray for some time, but is ultimately squashed. Back in 2012, a paper was published claiming a sizable effect on life span in rats via treatment with C60 in olive oil. There were red flags at the time: it was published in a journal outside the field of aging research, used a very small number of animals, and the size of the effect on life span was just too large to be credible. Peer review would have sunk this paper if submitted to an aging-focused journal. C60 is an antioxidant, so even if it is acting in the best possible way for antioxidants to act (i.e. targeting mitochondria while leaving the rest of the cell alone) it shouldn't be doing much better than other existing mitochondrially targeted antioxidants, many of which have a fair amount of published animal data to reference.

Unfortunately, one can't ignore large effect sizes, even when they are implausible and the study that produced them looks dubious. I said at the time that this was likely to go nowhere, didn't look good on the face of it, but nonetheless people were going to spend funds on trying to replicate it and dig into the biochemistry. It took a couple of years for those efforts to start up in earnest. The Methuselah Foundation funded some of this work, alongside Longecity and a few other organizations. The Ichor Therapeutics team carried out the heavy lifting. From the get-go, the work case doubt on the original paper, discovering that C60 in olive oil is quite challenging to formulate in ways that prevent toxicity. It took some years of working at the problem to carry out a reasonable animal study.

Now, eight years later, the results of that labor are published. As suspected, this is a dead end, and that initial 2012 paper looks the worse for someone taking the time to properly close the door on this line of work. This exercise illustrates why one should apply an appropriate level of skepticism to what one reads in the literature, and why journal boards should refrain from publishing data that lies outside their area of specialty. It also shows the self-correcting nature of scientific progress at work: replication is vital, as that is how errors are checked and removed once they take place. It takes far too long and costs far too much, but remains the least worst option.

C60 in olive oil causes light-dependent toxicity and does not extend lifespan in mice

C60 is a potent antioxidant that has been reported to substantially extend the lifespan of rodents when formulated in olive oil (C60-OO) or extra virgin olive oil (C60-EVOO). Despite there being no regulated form of C60-OO, people have begun obtaining it from online sources and dosing it to themselves or their pets, presumably with the assumption of safety and efficacy.

In this study, we obtain C60-OO from a sample of online vendors, and find marked discrepancies in appearance, impurity profile, concentration, and activity relative to pristine C60-OO formulated in-house. We additionally find that pristine C60-OO causes no acute toxicity in a rodent model but does form toxic species that can cause significant morbidity and mortality in mice in under 2 weeks when exposed to light levels consistent with ambient light.

Intraperitoneal injections of C60-OO did not affect the lifespan of CB6F1 female mice. Finally, we conduct a lifespan and health span study in males and females C57BL/6 J mice comparing oral treatment with pristine C60-EVOO and EVOO alone versus untreated controls. We failed to observe significant lifespan and health span benefits of C60-EVOO or EVOO supplementation compared to untreated controls, both starting the treatment in adult or old age. Our results call into question the biological benefit of C60-OO in aging.

Towards Better Quantification of AGEs and Cross-Links in Human Tissues
https://www.fightaging.org/archives/2020/11/towards-better-quantification-of-ages-and-cross-links-in-human-tissues/

Cross-links that join together molecules of the extracellular matrix are necessary for the normal structural properties of tissue. Cross-links can also be formed in a detrimental way by advanced glycation endproducts (AGEs), a form of metabolic waste, and thereby impair structural properties of tissue. Most AGEs are short-lived, but some are quite persistent, hard for our biochemistry to break down, and build up with age. High levels of AGEs are characteristic of an abnormal metabolism, such as in diabetic patients, and can cause long-term harm by promoting inflammation and altered cellular behavior through the receptor for AGEs (RAGE).

Persistent cross-links formed by AGEs, rather than by normal tissue maintenance processes, can reduce elasticity in skin and blood vessels. Of interest to the authors of today's open access research is the question of how AGEs might degrade the strength and resilience of bone or cartilage. Is it via formation of cross-links, or via some other mechanism?

Working with cross-links is challenging. There are many different types of AGE, with quite different characteristics. It is not an area of molecular biochemistry that has received the attention that it deserves, and as a result there are deficiencies in the tools and understanding. Cataloging the amounts and consequences of specific types of AGE in tissues is lagging, and there are uncertainties attached to the present consensus, even the very compelling view that glucosepane is the most important age-related cross-linking AGE, and thus the best target for treatments to break down AGEs.

Given the very different effects resulting from short-lived versus persistent AGEs, or different AGEs with different biochemical interactions, it is rather important to understand the breakdown of AGEs rather than just bulk amounts of various categories of AGEs. Additionally, since AGEs tend to be produced through similar mechanisms, there is no guarantee that any particular AGE is the important damaging mechanism even if when it is unambiguously associated with disease and loss of function. Production of the AGE under consideration may be correlated with the production of many other AGE types, one of which is an important damaging agent. Thus there is a lot of work left to accomplish in this part of the field, and at least some of it will look a lot like today's open access paper.

Mass spectrometric quantitation of AGEs and enzymatic crosslinks in human cancellous bone

Material property of bone is an important determinant of bone strength. The nanoscale structures of bone are formed from collagen fibers surrounded and infiltrated with hydroxyapatite minerals. Collagen fibers provide the material properties such as tensile strength, ductility and toughness, while hydroxyapatite minerals are thought to contribute to stiffness. The functional properties of collagen are influenced by posttranslational modifications (PTMs). Among the modifications, the formation of enzymatic crosslinks between collagen fibrils are essential for physiological bone strength. On the other hand, damaging to bone strength, advanced glycation end-products (AGEs) are the results of non-enzymatic PTMs.

A series of basic and clinical trials have clarified the link between the accumulation of AGEs in bone collagen, and deterioration of bone strength. An in vitro glycation of bovine cortical bone induced pentosidine, an AGE compound, which resulted in reduced stiffness and post-yield strain. This phenomenon was also demonstrated in human cancellous bone. An in vivo study involving spontaneously diabetic rats also revealed that after the onset of diabetes, there was an increase in pentosidine accumulation in the femur with decreased bone strength despite no reduction in bone mineral density. Moreover, the link between AGEs and bone strength has been demonstrated in clinical trials. Urinary excretion of pentosidine, which is used as a surrogate marker for bone AGEs, was shown to be a predictor of vertebral fracture after adjustment for age, bone mineral density, and renal function.

In this study, we established a system that enabled the quantitation of five AGEs (CML, CEL, MG-H1, CMA and pentosidine), as well as two mature and three immature enzymatic crosslinks, in 149 human cancellous bone samples. We examined the patterns of AGEs accumulation to investigate whether pentosidine or total fluorescent AGEs (tfAGEs) more accurately reflects the actual AGEs status in bone collagen. As the clinical manifestations of AGEs accumulation include aging, diabetes and renal failure, we also analyzed the association between AGEs and the clinical parameters such as age, gender, BMI, history of diseases, glycated hemoglobin (HbA1c) as the marker of blood glycemic status over several weeks to months, tartrate-resistant acid phosphatase-5b (TRACP-5b) as the measure of bone resorption, and estimated glomerular filtration rate (eGFR).

The results showed that MG-H1 was the most abundant AGE, whereas pentosidine was 1/200-1/20-fold less abundant than the other four AGEs. The AGEs were significantly and strongly correlated with pentosidine, while showing moderate correlation with tfAGEs. In single and multiple regression analyses, gender was the strongest determinant of the AGEs, followed by age, TRACP-5b, HbA1c, and BMI. The gender difference in oxidative stress and carbonyl stress may explain this. In addition, CML and CEL, the non-crosslinking AGEs, were negatively correlated with the immature crosslinks. This result raises the possibility that non-crosslinking AGEs attribute to the deterioration of bone strength by inhibiting the formation of enzymatic crosslinks.

Inflammation in the Age-Related Thickening and Stiffening of Blood Vessel Walls
https://www.fightaging.org/archives/2020/11/inflammation-in-the-age-related-thickening-and-stiffening-of-blood-vessel-walls/

Age is characterized by a growing degree of unprompted, unresolved inflammation. Inflammation is a rousing of the immune system into action, a necessary process that aids in the defense of the body against pathogens, as well as in regeneration of injuries. In youth, inflammation is near always promptly resolved once the need is passed. In old age, however, inflammation becomes constant, triggered by many distinct causes: persistent infections; metabolic waste; the breakdown of the intestinal barrier and the blood-brain barrier, leaking unwanted molecules, cells, and pathogens; and rising numbers of senescent cells that secrete inflammatory signals.

Constant, unresolved inflammation is disruptive of tissue maintenance and function throughout the body. In recent years, the research community has demonstrated quite conclusively that accumulation of senescent cells in old tissues causes a significant fraction of this chronic inflammation of aging. Targeted removal of as few as a third of the senescent cells present in tissue via senolytic therapies reduces inflammatory signaling and reverses many of its consequences. This has been amply demonstrated in mice, but human trials of first generation senolytic drugs have to date only assessed a few conditions and a few different approaches to destruction of senescent cells.

As noted in today's open access paper, inflammation and cellular senescence is important in the vascular stiffening and thickening of age, a process that contributes to hypertension and all of the major damage to tissues and systems in the body and brain then caused by chronically raised blood pressure. Interestingly, it is possible to link increased levels of cellular senescence in blood vessel walls with the presence of advanced glycation end-products (AGEs), sugary metabolic waste that forms cross-links between collagen and other molecules of the extracellular matrix, changing the structural properties of tissue as a result. Reduced elasticity (i.e. stiffening) is one direct consequence, but these changes also likely cause nearly cells to react in ways that increase the burden of cellular senescence in that tissue.

Proinflammation, profibrosis, and arterial aging

Aging is a major risk factor for the morbidity and mortality of quintessential cardiovascular diseases, such as hypertension and atherosclerosis, mainly due to arterial wall structural and functional adverse remodeling, such as intimal medial thickening (IMT) and stiffening. The age-associated increase in collagen deposition within the arterial wall is known as arterial profibrosis; and the age-associated increase in sterile inflammation within the wall is known as arterial proinflammation. Proinflammation and profibrosis are the key molecular and cellular events in age-associated IMT and arterial stiffening. It is widely accepted that proinflammatory endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are mainly responsible for age-associated adverse arterial cellular events; however, the consequence of proinflammation and profibrosis (predisposing collagen deposition) greatly affects the behavior of these cells adversely with a predominant impact on the age-associated arterial stiffening, which is not completely understood.

In the aging arterial wall, collagen types I, II, and III are predominant, and are mainly produced by stiffened vascular smooth muscle cells (VSMCs) governed by proinflammatory signaling, leading to profibrosis. Profibrosis is regulated by an increase in the proinflammatory molecules angiotensin II, milk fat globule-EGF-VIII, and transforming growth factor-beta 1 (TGF-β1) signaling and a decrease in the vasorin signaling cascade. The release of these proinflammatory factors triggers the activation of matrix metalloproteinase type II (MMP-2) and activates profibrogenic TGF-β1 signaling, contributing to profibrosis. The age-associated increase in activated MMP-2 cleaves latent TGF-β and subsequently increases TGF-β1 activity leading to collagen deposition in the arterial wall.

Collagen fibrils become resistant to cleavage over time. Mice with a targeted mutation that yields collagenase-resistant type I collagen create an old senescent phenotype. VSMCs in the aortic wall of these mutated mice are susceptible to stress-induced cellular senescence, displaying senescence-associated beta-galactosidase (SA-β-Gal) activity and upregulated p16 in response to angiotensin II infusion. In addition, mutant collagen directly reduces the replicative lifespan of human VSMCs and increases stress-induced measures of cellular senescence such as SA-β-Gal activity, p16 expression, and p21 expression. Thus, resistance to collagen cleavage, such as advanced glycation endproduct (AGE) formation, accelerates cellular senescence, arterial stiffening, and aging. A long-term senolytic treatment (intermittently with dasatinib + quercetin via oral gavage) significantly eliminates senescent cells in the medial layer of aortae from aged mice and reduces arterial stiffening.

Continuing to State the Obvious on Vulnerability to COVID-19 Due to Aging
https://www.fightaging.org/archives/2020/11/continuing-to-state-the-obvious-on-vulnerability-to-covid-19-due-to-aging/

Not every SARS-CoV-2 infection in the COVID-19 pandemic is equal. Young people near all shrug off infection with a few weeks of inconvenience at worst. Old people, on the other hand, exhibit more significant illness and a high mortality rate. That mortality rate increases with both advancing age and the presence of inflammatory age-related chronic disease. The average 20 year old has a radically different risk profile when compared to the average 80 year old. This is one of the reasons why the commonly presented data, estimated infections per capita, or detected infections over time, is unhelpful. It needs the context of the age of the patients.

The popular media shows no inclination to correctly present SARS-CoV-2 as being a meaningful threat only to older people, tending to focus on overall infection counts, as well as on the tiny number of young people who are greatly impacted or killed by SARS-CoV-2. Meanwhile, the scientific community continues to publish papers that state the obvious on this topic. Viral infection disproportionately harms old people because of immunosenescence and inflammaging, the age-related decline in immune system competence and function. The best way to address the problem of mortality due to infectious disease in the elderly is to build therapies that can restore immune function.

There are many plausible approaches to improved immune function in the old. Regrowing the thymus. Improving hematopoietic stem cell function. Clearing out malfunctioning or damaged populations of immune cells. Regenerating fibrotic lymph nodes. A great deal more funding and effort should be directed towards these goals than is presently the case.

Aging in COVID-19: Vulnerability, immunity and intervention

The majority of COVID-19 cases are mild. Some people may not have any clinical manifestation at all after SARS-CoV-2 infection. These asymptomatic individuals can serve as a source of virus spread. A report of the data in New York State up to March 31, 2020 showed that 47,326 persons out of 141,495 were tested positive (33%) for COVID-19, and many of those positives were asymptomatic. However, more surveillance data are needed to evaluate the extent of asymptomatic infection. In an infectious disease as heterogeneous as COVID-19, host factors are the key to determine disease severity and progression. For severe COVID-19 disease, major risk factors include age, male sex, obesity, smoking, and comorbid chronic conditions such as hypertension, type 2 diabetes mellitus, and others. Overwhelming evidence from around the world suggests that age itself is the most significant risk factor for severe COVID-19 disease and its adverse health outcomes.

Early data from China demonstrate that case fatality ratio (CFR) of COVID-19 increases with age, from 0.4% or lower in patients aged in the 40s or younger, 1.3% among those in their 50s, 3.6% in their 60s, 8% in their 70s, to 14.8% in their 80s or older; the overall CFR is 2.3%. In comparison, the overall CFR was approximately 2.8% worldwide and 2.7% in the US as of October 19, 2020. A more profound effect of aging is shown by COVID-19 CFR data from Italy, the first country affected by the pandemic after China. Again, CFRs are from less than 0.4% or lower in patients aged in the 40s or younger, 1% among those in their 50s, 3.5% in their 60s, 12.8% in their 70s, to 20.2% in their 80s and above; the overall CFR is 7.2%. Of note, the overall CFR is higher in Italy than that in China (7.2% vs 2.3%, respectively). This is likely because Italy not only has a higher CFR than China among adults over 70 years of age, but also has a higher proportion of older adults than China (22.8% vs 11.9%, respectively).

Data reported by the US Center for Disease Control and Prevention (CDC) also demonstrate significantly higher rates of hospitalizations, ICU admissions, and deaths secondary to COVID-19 among older adults (older then 65 years) than any younger age groups. Perhaps, the most striking evidence is the data on COVID-19 cases and death in nursing homes across the US. Currently, there are up to 1.5 million nursing home residents in the US, less than 0.5% of its population. However, about 7% of confirmed COVID-19 cases were among these vulnerable elderly individuals. Moreover, they suffered 40% of COVID deaths in the US. Taken together, it is unmistakable that aging is an important risk factor for severe COVID-19 disease and its adverse health outcomes including hospitalization, ICU admission, and death.

Strategies to Treat Vascular Aging
https://www.fightaging.org/archives/2020/11/strategies-to-treat-vascular-aging/

The vascular system does not age gracefully. Blood vessel walls become stiff and inflamed, interfering in contraction and dilation in response to circumstances. The result is the raised blood pressure of hypertension, which causes damage throughout the body in numerous ways. Further, the fatty lesions of atherosclerosis form in later life, weakening and narrowing blood vessels. This is the result of increased levels of oxidized cholesterol molecules, causing the macrophages responsible for cleaning up blood vessel wall tissues to falter in their tasks. Further still, the blood-brain barrier that lines blood vessels in the brain breaks down and leaks unwanted cells and molecules into brain tissue, causing neuroinflammation and the onset of cognitive decline. But there is more than even this, such as the loss of capillary network density that leads to a declining supply of nutrients and oxygen to tissues throughout the body.

Today's short open access paper is a brief tour of a few strategies for which there is evidence for their application to reduce the impact of vascular aging. It is a mixed bag in terms of size of effect, reliability, and quality and amount of evidence. The best of the bunch is likely senolytic therapies that selectively destroy senescent cells, but even here, while the animal data is quite impressive, that outcome remains to be proven in human trials. The point to take away from this is that the aging of the vascular system is quite important in the progression of degenerative aging. A great many issues lie downstream of hypertension, blood-brain barrier dysfunction, and the other manifestations of vascular aging, and so successful interventions will be broadly beneficial.

Novel update of interventional strategies of vascular aging in humans

Classical strategies targeting mechanisms of vascular aging to delay vascular aging and prevent disease, such as exercise, diet, and other lifestyle interventions, have far-reaching significance. However, these alone seem to be insufficient to prevent the occurrence of geriatric disease and efforts are needed to tackle the underlying processes of vascular aging. At present, the most promising novel strategies for delaying vascular aging include improving the function of mitochondria, reducing age-related inflammation, increasing autophagy, moderately reducing the activity of the nutrient-sensing network, especially reducing the activity of mammalian target of rapamycin complex 1 (mTORC1), removing senescent cells, and using its own endogenous metabolites to re-energize stem cells, and so forth. Several potential drugs and natural products have been reported to modulate aging. Shedding light on the mechanisms of vascular aging and the development of novel agents will likely reduce the risk of age-related disease and extend the human health span.

Senolytics

Senolytics is a class of drugs that selectively kill senescent cells, and scientists have reported the first senolytics drug combination - dasatinib + quercetin. Recent studies demonstrated that senolytic treatment exerted a positive effect on senescent cell burden, DNA damage, vasomotor function, nitric oxide signaling, calcification, and osteogenic signaling in chronologically aged mice. Another study indicated that this combination selectively cleared senescent cells in idiopathic pulmonary fibrosis mice and improved lung function and physical health indicators in mice. In an open-labeled phase I clinical trial, nine patients with diabetic nephropathy received dasatinib and quercetin therapy, which reduced the load of adipose tissue senescent cells. The effect of senolytic treatment may be mediated by members of the BCL-2 family, PI3K/AKT, p53/FOXO4, HSP90, and HIF1α. These results proved that senolytics are expected to be used to delay vascular aging and prolong the life span of the elderly.

Metformin

Metformin is a biguanide drug widely used for type 2 diabetes. A study on mice found that treatment with metformin mimics some of the benefits of calorie restriction, such as increased insulin sensitivity and reduced low-density lipoprotein and cholesterol levels and finally improves health span and life span. Retrospective, epidemiological analyses elucidated that administration of metformin is associated with the improvement of vascular function and reductions in the incidence and mortality of ischemic disease. The results of metformin treatment in age-related disease are also encouraging, with a wide range of protective roles in cardiovascular disease, cerebrovascular disease, cancer, chronic kidney disease, and neurodegeneration.

Rapamycin

Studies showed that rapamycin destabilizes and inhibits mTORC1, which is an important molecule regulating various cellular processes. It was proposed that rapamycin extended the life span by up to 60% and even reversed the changes in vascular function and structure, cognition, cardiac hypertrophy, and immune senescence in aged mice, through both genetic and pharmacological modulation of mTOR signaling. The current clinical uses of rapamycin may be limited by its adverse effect to some extent, including hyperglycemia and hyperlipidaemia. As an effective anti-vascular aging agent, rapamycin has both advantages and disadvantages and it should be balanced for every individual.

Nicotinamide adenine dinucleotide and sirtuins

Nicotinamide adenine dinucleotide (NAD+), as a cofactor in many key biological processes of cells, is an important mediator of biochemical reactions in the body and an essential molecule in many metabolic pathways. It has been found that the concentration of NAD+ in human tissues gradually decreases with age, and at least decreases by 50%, accompanied by a series of pathological processes, such as chronic inflammation, oxidative stress, DNA damage, and mitochondrial dysfunction. Supplementation of NAD+ and its precursors is beneficial to reduce the occurrence of oxidative stress, increase the regenerative capacity of vascular endothelial cells, and prolong cell life.

Berberine

Berberine is an isoquinoline alkaloid extracted from various plants, which plays an important role in lowering blood pressure, regulating blood lipids, and controlling blood glucose. It was found that berberine could activate the AMPK-signaling pathway, and inhibit the activity of mTOR to delay cell senescence caused by DNA replication disorder, and also increase antioxidant activity by activating the NRF2-signaling pathway to achieve the effect of longevity extension.

Nucleoside reverse transcriptase inhibitors

Nucleoside reverse transcriptase inhibitors (NRTIs) are used in clinical HIV treatment, but can also inhibit open-reading frame-related reverse transcriptase activity of long dispersive elements. Recent studies have found that NRTIs, including lamivudine and stavudine, can reduce senescence-related secretory phenotypes and inflammatory responses in older mice. These findings make NRTIs a new candidate for delaying aging.

Remote ischemic preconditioning

Remote ischemic preconditioning (RIPC) is a safe, noninvasive, simple, and low-cost non-drug device intervention and has been widely used since it was first proposed. RIPC is an intrinsic protective phenomenon to protect the vital organs with non-fatal regional ischemia followed by reperfusion, through the involvement of SDF-1α, HIF-1α, oxidative stress, and apoptotic pathways. A recent study has demonstrated that 1-month RIPC treatment can significantly reduce the blood pressure of patients with mild essential hypertension and improve microvascular endothelial function.

Implicating TFAM in the Mitochondrial Dysfunction that Accelerates Immune Aging
https://www.fightaging.org/archives/2020/11/implicating-tfam-in-the-mitochondrial-dysfunction-that-accelerates-immune-aging/

This short commentary looks at just one cell type, T cells of the adaptive immune system, in which loss of mitochondrial function produces issues such as cellular senescence that contribute to broader degenerative aging throughout the body. Every cell contains hundreds of mitochondria, responsible for producing adenosine triphosphate, an energy store molecule used to power cellular processes. When that supply diminishes, everything suffers as a consequence: cell function, tissue function, health. With age, mitochondrial function is observed to decline throughout the body. This is likely the result of signaling and gene expression changes that hinder the quality control mechanism of mitophagy, and thus worn and damaged mitochondria are not effectively recycled. Deeper connections to the root causes of aging are not yet well understood, however.

Mitochondrial dysfunction is a key event in many pathologies and contributes to the ageing process. Mitochondria have been shown to participate in every aspect of ageing, from a decline in stem cell function and cellular senescence, through to the development of the low grade inflammatory state. Alterations that occur to mitochondria with age are numerous and can be observed in many different cells and tissues. Indeed, we have shown that human CD8+ T cells were more susceptible to senescence compared to their CD4+ counterparts as they displayed a lower mitochondrial content and postulated loss of mitochondrial function controls the senescence phenotype in T cells as well as other cell types. However the mechanism remained elusive, that is until recent work demonstrated that mitochondrial dysfunction was controlled by mitochondrial transcription factor A (TFAM).

In order to examine the links between mitochondrial loss and ageing, researchers used TFAM deficient mice, Tfamfl/flCd4Cre. TFAM is a nuclear gene that controls the stabilisation and replication of mitochondrial DNA. They found T cell mitochondrial content declined along with the loss of components of the electron transport chain causing a switch in T cell metabolism towards glycolysis. Interestingly they found young Tfamfl/flCd4Cre mice had a metabolic profile that resembled wild type 22 month mice, which was associated with Th1 skewing and increased expression of the Th1 master regulator T-bet. Additionally Tfamfl/flCd4Cre mice were also immunocompromised.

Further evidence for TFAM being associated with ageing came from the observation that 7 month Tfamfl/flCd4Cre mice had an elevated inflammatory burden or inflammageing more usually seen in older animals. This increased inflammation is a predictor of multimorbidity during ageing and Tfamfl/flCd4Cre mice were found to have premature loss of muscular, cardiovascular, and cognitive fitness together with a shorten life span. TFAM deficient animals were found to be less active and slower with less hypodermal fat than controls despite a higher energy expenditure.

The authors validated that this multimorbidity phenotype was due to a mitochondrial defect specifically in T cells by creating a T cell-specific Tfam deficient mouse model, Tfamfl/flLckCre. These animals also showed a prematurely aged phenotype by elevated expression of the senescence-associated markers p21 and p53. Incubation of hepatocytes or pre-adipocytes with serum from Tfamfl/flCd4Cre animals or with TNFα also increased p21 expression, supporting the idea that inflammation induces senescence and premature ageing. They also gave Tfamfl/flCd4Cre animals nicotinamide riboside (NR), the NAD+ precursor that declines with age and is a metabolic cofactor with a critical role in mitochondrial function. The use of NR was found to be protective against premature senescence and most but not all features of multimorbidity.

The paper concludes that T cells are capable of regulating both health and lifespan as well as highlighting the importance of tight immunometabolic control during ageing and the onset of age-related diseases. Finally, this work cements the idea that mitochondria play a causal role in senescence and that increasing mitochondrial biogenesis when coupled with mitochondrial degradation confers a survival advantage at both the cellular and organismal level.

Transcriptomic Aging Clocks can be Improved by Combining Results from Different Tissues
https://www.fightaging.org/archives/2020/11/transcriptomic-aging-clocks-can-be-improved-by-combining-results-from-different-tissues/

The transcriptome of a cell is an assessment of gene expression at a moment in time, specifically which genes have RNA transcripts under production, and the relative amounts of those transcripts. Like all such detailed cell data, the transcriptome changes with age in characteristic ways, a reaction to the presence of ever greater amounts of cell and tissue damage. Those changes can be used to produce clocks that measure biological age, very similar to the more established epigenetic clocks based on DNA methylation. The transcriptome varies by cell type, and here researchers note that combining transcriptomes from different tissues produces a more accurate result than is the case for single tissue clocks.

Studying transcriptome chronological change from tissues across the whole body can provide valuable information for understanding aging and longevity. Although there has been research on the effect of single-tissue transcriptomes on human aging or aging in mice across multiple tissues, the study of human body-wide multi-tissue transcriptomes on aging is not yet available.

In this study, we propose a quantitative model to predict human age by using gene expression data from 46 tissues generated by the Genotype-Tissue Expression (GTEx) project. Specifically, the biological age of a person is first predicted via the gene expression profile of a single tissue. Then, we combine the gene expression profiles from two tissues and compare the predictive accuracy between single and two tissues.

The best performance as measured by the root-mean-square error is 3.92 years for single tissue (pituitary), which deceased to 3.6 years when we combined two tissues (pituitary and muscle) together. Different tissues have different potential in predicting chronological age. The prediction accuracy is improved by combining multiple tissues, supporting that aging is a systemic process involving multiple tissues across the human body.

The Direction of Causation Between Fibrosis and Cellular Senescence
https://www.fightaging.org/archives/2020/11/the-direction-of-causation-between-fibrosis-and-cellular-senescence/

A fair amount of evidence points to senescent cells as causative of fibrosis, the deposition of scar-like collagen structures in tissue that disrupt organ function. This evidence includes reversal of fibrosis in animal models via selective destruction of senescent cells, a promising finding given the poor and limited options presently available for the treatment of fibrosis in human medicine. The paper here suggests that the relationship between fibrosis and cellular senescence is more complex, however, in that fibrotic changes in the extracellular matrix may act to induce greater levels of cellular senescence. Clearly there is more work to be done on this topic, but given the ability to destroy senescent cells via senolytic drugs, we might expect meaningful progress towards a better understanding in the years ahead.

Fibrotic diseases are characterised by deposition of excessive extracellular matrix (ECM) after injury resulting in organ dysfunction. While little is known about the exact mechanisms that result in excessive ECM deposition and accumulation in fibrotic disease, there is increasing evidence that cellular senescence is implicated in fibrosis. One major under-recognised element in fibrosis is the contribution of the ECM itself. It is known that the altered composition and increased cross-linking leads to an altered topography and stiffness. These changes alter cellular behaviour and might potentially drive cells to become senescent contributing to an environment favouring disease progression.

Increased ECM stiffness is a feature of fibrosis and is thought to result from the quantity of ECM deposition and the degree of its cross-linking. The mechanical properties of areas of wounded tissue significantly change in rat liver fibrosis. It was suggested that this was the result of increased cross-linking of the ECM fibres, rather than increased ECM deposition after the initial insult. These results suggest that cross-linking of ECM has a greater impact on stiffness and thus altered mechanical properties than the quantity of deposited ECM alone.

In fibrotic disease, the increased cross-linking has not only been associated with increased stiffness but also in higher resistance to proteolytic degradation as the conformational changes lead to less accessible epitopes for matrix metallopeptidases. The stiffness of the ECM directly influences the behaviour and function of cells including increased fibroblast proliferation, migration and contraction. Furthermore, a stiffer ECM leads to an increase in latent transforming growth factor-β (TGF-β) activation which reinforces fibrosis and it has been linked to cellular senescence. TGF-β contributes to the induction of senescence or the acceleration of transformation into senescence in various cell types.

Current therapeutic approaches for modulating senescence aim to specifically kill aberrant cells that have entered the senescent state. This includes several drugs (for example quercetin and dasatinib) that were originally developed for targeting tumours. However, as some of the markers that are present in malignant cells are also specifically expressed in senescent cells these agents have now been repurposed as senolytic agents. These drugs have been shown to effectively reduce the number of senescent cells, and in some cases decrease fibrosis, at least in preclinical models, potentially through modulation of the pro-inflammatory SASP released by the senescent cells.

In a first human, open label pilot study, the potential application of dasatinib and quercetin was tested in 14 patients with idiopathic pulmonary fibrosis. There was a significant improvement in the physical condition of the patients, but the pulmonary function of the patients did not change within this short trial period. Circulating SASP factors were measured, and while no significant change was reported there was a suggestion of reduced levels of selected proteins important for fibrotic remodelling, including IL-6, MMP, and TIMP2. Intriguingly, changes in pulmonary function and physical condition of the patients correlated with changes in the circulating levels of matrix remodelling proteins. While this is a very early study that needs to be validated in a much larger population in a randomised controlled trial, these observations further suggest that the role of the ECM should not be overlooked when striving to understand the regulation of senescence in fibrosis.

A Loss of Transcriptional Coordination Observed in Cells from Older Individuals
https://www.fightaging.org/archives/2020/11/a-loss-of-transcriptional-coordination-observed-in-cells-from-older-individuals/

Existing evidence suggests that transcription of genetic blueprints into RNA becomes less coordinated with age, producing greater variance between cells. It is a question mark as to how greatly this contributes to age-related disease, and also a question mark as to exactly how it is linked to the underlying molecular damage at the root of aging. Expanding this area of research, scientists here show that within individual cells the coordination of transcription between genes also becomes dysregulated. The more age-related damage there is in tissues, the worse the dysregulation of transcription. A potential next step might be to assess this effect before and after the application of a rejuvenation therapy, such as clearance of senescent cells, in order to clearly demonstrate whether or not disruption of transcriptional coordination is a reaction to cell and tissue damage of aging.

How is it that random, disorganized damage, which accumulates differently among different humans, and moreover, among different cells of the same individual eventually leads to the same outcomes? Several theories try to address this paradox, and they have great implications for our ability to affect the aging process, making elderly life better and longer. The potential to develop treatments for aging depends on understanding the fundamental process of growing old.

A common approach holds that most cells in the human body are barely damaged during aging, while just a few "rotten apples" - a small fraction of non-functioning cells - are significantly damaged. Accordingly, a potential treatment for aging could involve removing these few highly-damaged cells. Researchers have also suggested that the proper function of biological tissues may decline during aging because many cells lose their ability to tightly regulate their genes. According to this theory, there are no single non-functioning cells - or rotten apples - on the one hand, but none of the apples is "fresh" on the other.

Using a novel approach from physics, researchers developed a computational method that quantifies the coordination level between different genes. With this approach, they measured the transcriptional activity of individual cells and compared cells from old and young subjects, discovering phenomena never before observed: old cells lost significant coordination levels compared to young cells. To test the consistency of this phenomenon, they analyzed data collected from more than twenty experiments from six different labs. In all cases they found reduced levels of coordination during aging among different organisms: human, mice, and fruit flies, and among different cell types: brain cells, hematopoietic stem cells, pancreatic cells, and more.

The researchers also observed coordination reduction in tissues with an increased level of damage, suggesting a direct link between increased damage level and coordination breakdown. The findings support the theory that during aging, accumulated random damage affects regulation mechanisms and disrupts the ability of genes to coordinate, resulting in a general decrease in tissue function. This study conclusively demonstrates the long-speculated relationship between aging, gene regulation, and somatic damage. The results open up new avenues of research with practical implications. If the same level of coordination reduction between genes is indeed a leading cause for aging phenomena, there may be a need to change course in current efforts to develop aging treatments.

Using Oligodendrocyte Extracellular Vesicles to Induce Tolerance to Myelin as a Treatment for Multiple Sclerosis
https://www.fightaging.org/archives/2020/11/using-oligodendrocyte-extracellular-vesicles-to-induce-tolerance-to-myelin-as-a-treatment-for-multiple-sclerosis/

In multiple sclerosis, the immune system becomes intolerant towards myelin, the sheathing around nerves that is essential to nervous system function. One class of approach to treating autoimmune diseases of this nature is to produce immune tolerance by delivering more of the problem molecule into the body. The challenge in multiple sclerosis is that it is unclear as to which of the many possible protein sequences is the problem in any given patient, and indeed to build a comprehensive list of such sequences in the first place. Researchers here report on the discovery that the oligodendrocyte cells responsible for building and maintaining myelin sheathing secrete a wide variety of myelin antigens in extracellular vesicles. These vesicles are comparatively easy to harvest from cell cultures, and thus are a good potential basis for an immune tolerance therapy that could work for all multiple sclerosis patients.

Multiple sclerosis (MS) is an autoimmune disorder that develops as the body's immune system attacks the central nervous system. Specifically, it attacks the protective layer surrounding nerve cells, called the myelin sheath. Current MS therapies aim to counter this inflammatory response by suppressing the immune system, which can lead to serious side effects like a higher risk of infection, and even cancer. Researchers have found a way to prevent immune cells from attacking myelin and halt disease progression, while leaving the rest of the immune system intact, in mouse models of MS.

"There are many possible immune-activating antigens in the myelin sheath, but the biggest hurdle is that we don't know which component of myelin is triggering the immune response in MS patients. Previous studies have used single myelin antigens or combinations of antigens to prevent auto-immunity in animal models, but in humans they have had limited success." For answers, the researchers turned to cells called oligodendrocytes. These cells wrap their cell membrane around nerve cells to produce the myelin sheath. Tiny sacs called extracellular vesicles (EVs) can be harvested from cultured oligodendrocytes. The researchers found that these EVs contain almost all the relevant myelin antigens. With all of the antigens present, there'd be a higher chance that these vesicles could halt the autoimmune attack on myelin. "The neat thing about these EVs is that they give us an opportunity to treat the disease in an antigen-specific way, without having to know the exact identity of the target antigen. It covers all the bases."

The researchers were able to safely inject the EVs intravenously in three different mouse models of MS representing early and late stages of the disease. When administered before disease developed, the EVs had a prophylactic effect, preventing the onset of symptoms like decrease in mobility and paralysis. When given after disease onset, EVs significantly reduced severity of disease in all three models, to the point that the animals could walk again. "The antigens involved in the auto-immune response can differ between MS patients, and even change over time in an individual patient. The fact that our approach was effective in different experimental models shows this could act as a universal therapy."

Reviewing the Development of Therapies to Target Cellular Senescence
https://www.fightaging.org/archives/2020/11/reviewing-the-development-of-therapies-to-target-cellular-senescence/

Senescent cell accumulation is an important feature of aging, both for its contribution to the chronic inflammation of old age, as well as the disruption of tissue function that leads to age-related disease. Targeting senescent cells for destruction via senolytic drugs is an area of clinical development that is growing in popularity, but it isn't the only possible approach. This paper is interesting for its taxonomy of drugs and other compounds that either selectively destroy senescent cells, prevent cells entering senescence, or mute portions of the senescence-associated secretory phenotype (SASP) that causes harm to surrounding cells and tissues. These strategies will likely turn out to be widely divergent in risk and outcome; selective destruction still appears the best of them to my eyes. But read the whole paper, as the summary below isn't the point of it, but rather the list and categorization it provides.

Aging leads to a high burden on society, both medically and economically. Cellular senescence plays an essential role in the initiation of aging and age-related diseases. Recent studies have highlighted the therapeutic value of senescent cell deletion in natural aging and many age-related disorders. However, the therapeutic strategies for manipulating cellular senescence are still at an early stage of development. Among these strategies, therapeutic drugs that target cellular senescence are arguably the most highly anticipated. Many recent studies have demonstrated that a variety of drugs exhibit healthy aging effects.

Senolytics are agents that selectively induce the apoptosis of senescent cells. This type of drug can be classified into BCL family inhibitors, PI3K/AKT inhibitors, and FOXO regulators. The BCL family is composed of pro-apoptotic proteins and pro-survival proteins. The PI3K/AKT pathway is one of the pro-survival pathways in senescent cells. Studies have shown that phosphoinositide 3-kinase (PI3K) is involved in protecting cells against apoptosis. FOXOs controls cell functions such as growth, survival, metabolism, and oxidative stress. Studies have shown that FOXO4 can interact with p53, inhibit p53-mediated apoptosis, and thus maintain the vitality of senescent cells.

Another major feature of senescent cells is the acquisition of SASP. Drugs that target SASP, such as antioxidants, Wnt/β-catenin inhibitors, and Janus kinase (JAK) inhibitors, also have healthy aging effects since SASP is associated with a pro-inflammatory status and a faster aging rate.

The Aging of the Gut Microbiome in Alzheimer's Disease
https://www.fightaging.org/archives/2020/11/the-aging-of-the-gut-microbiome-in-alzheimers-disease/

The microbes of the human gut change with age, losing beneficial populations that promote tissue function throughout the body via the metabolites they generate, and gaining harmful populations that generate chronic inflammation and tissue dysfunction. The causes of this problem are varied and still under investigation, but it seems very plausible that methods of reversing the age-related alterations in microbial populations can be established. For example, fecal microbiota transplantation has been shown to restore a youthful gut microbiome and extend life in killifish, and is already used in human medicine for conditions in which pathogenic bacteria have overtaken the intestine. Equally, it seems likely that some novel, tailored form of high dose probiotic therapy could achieve similar results.

Generally, the gut microbial communities in human are stable; however, they can be altered in the different conditions by the effects of various factors. Recently, the studies of several groups have been demonstrated that various diseases, including intestinal diseases and more systemic diseases such as diabetes, metabolic syndrome, and neurodegenerative disorders, including Alzheimer's disease (AD) and others, are related to the imbalance of gut microbiota called "dysbiosis". Occurrence and development of AD and other neurodegenerative disorders may be accompanied by the gut microbiome dysbiosis, inflammation, and dysfunction of the gut-brain axis. It has been speculated that AD may appear during the aging of immune system based on the theory of age-related dysbiosis derived from the association between gut microbiota and AD, which has been evidenced by clinical and experimental studies.

Generally, the traditional ecological measures are used to characterize the composition of the gut microbiome, including richness (the number of unique operational taxonomic units, OTUs, present in a participant), alpha diversity (the richness and abundance of OTUs within each participant), and beta diversity (the similarity or difference in composition between participants). Declined microbial richness and diversity as well as a distinct composition of the gut microbiome were found in AD patients. The levels of differentially abundant genera were correlated with cerebrospinal fluid (CSF) biomarkers of AD pathology. In short, definite genera as more abundant in AD were related to greater AD pathology, whereas genera as less abundant in AD were associated with less AD pathology.

There is also a close interaction between gut microbes and the local as well as systemic immune system. In general, the gut dysbiosis could lead to dysfunctions of both innate and adaptive immune through several ways, such as changing antigen presentations, cytokines production, and lymphocyte functions, as well as increasing inflammation, etc., also can cause the gut-brain axis malfunction. In AD patients, the molecular and cellular alterations involving immune cells, such as T cells, B cells, microglia, etc., as well as immune mediators, occur not only in the peripheral blood, but also in the brain and the CSF, which may be associated with triggering immune response by the gut dysbiosis. The gut dysbiosis impacts on innate and adaptive immune response in AD patients obviously via activating immune/inflammatory cells, shifting them into inflammatory type to enhance immune mediated inflammatory response, and promoting neurodegeneration in the brain. The gut dysbiosis in AD was obviously correlated with more T helper 1 (TH1) cell infiltration into the brain, and increased T-cell infiltration in the brain parenchyma and peripheral T-cell responses to amyloid-β have been found in AD patients.

Identifying Proteomic Profiles Associated with Aging
https://www.fightaging.org/archives/2020/11/identifying-proteomic-profiles-associated-with-aging/

Many research groups are using the extensive data that can be gathered on protein levels, transcription, or epigenetic marks in order to construct clocks that measure the impact of aging on an individual. All of this data changes from moment to moment and from year to year, alongside health, environment, and the biological damage of aging. Accuracy in terms of correlation with chronological or biological age varies widely, but at a few of the clocks are quite good in this regard. The work here is one example of many similar projects presently underway, in which data is sifted in search of protein levels that change in characteristic ways with age.

The present study identified proteomic profiles associated with chronological age and proteomic signatures related to aging phenotypes in a unique population of older adults. Maintenance of homeostasis is important in successful aging, whereas major deviations from stable physiology that can be captured by changes in the proteome may reflect accelerated aging and disease prevalence. Our findings demonstrated that individuals with a family history of longevity exhibit a proteome that is suggestive of delayed aging. Additionally, we showed that clusters of proteins, which were associated with age, were also related to complex diseases and other age-associated phenotypes.

We hypothesized that the proteome can capture the biology underlying the physiological age and not simply the chronological age. We tested this hypothesis in a homogenous community-dwelling cohort of Ashkenazi Jewish older adults in whom ~4,265 plasma proteins were measured. As part of the study, we aimed to develop an age prediction model based on the proteome and to test whether it predicted mortality. In addition, our cohort was enriched with individuals with familial longevity, with approximately half of the cohort composed of offspring of parents with exceptional longevity who repeatedly demonstrated better health status compared to age-matched controls

In the 1,025 participants of the LonGenity cohort (age range: 65-95, 55.7% females), we found that 754 of 4,265 proteins were associated with chronological age. Pleiotrophin (PTN), WNT1-inducible-signaling pathway protein 2 (WISP-2), chordin-like protein 1 (CRDL1), transgelin (TAGL), and R-spondin-1(RSPO1), were the proteins most significantly associated with age. Weighted gene co-expression network analysis identified two of nine modules (clusters of highly correlated proteins) to be significantly associated with chronological age and demonstrated that the biology of aging overlapped with complex age-associated diseases and other age-related traits. Pathway analysis showed that inflammatory response, organismal injury and abnormalities, cell and organismal survival, and death pathways were associated with aging.

Protrudin Gene Therapy Provokes Regrowth in Injured Optic Nerve Cells
https://www.fightaging.org/archives/2020/11/protrudin-gene-therapy-provokes-regrowth-in-injured-optic-nerve-cells/

Nerves regenerate poorly, and the regrowth of axons linking neurons following injury is hampered by scar formation. Finding a way to force greater regrowth of nerve tissue is an important goal for the regenerative medicine community. A variety of methods have shown some promise in early stage studies, and the example here is one among many. There has to date been comparatively little progress towards the clinic, however.

Glaucoma is a disease caused by progressive damage to the optic nerve, which transfers visual information from the eye to the brain. Conventional treatments focus on reducing eye pressure to prevent optic nerve damage, but they do not work for about 15 per cent of patients and there is currently no way to repair damaged nerve cells.

Researchers tested whether a gene responsible for producing a protein known as protrudin could stimulate the regeneration of nerve cells and stop them from dying when they were injured. They used a cell culture system to grow brain cells in the lab and then injured them using a laser before introducing a gene to increase the amount of protrudin in the cells, vastly increasing their ability to repair and regenerate.

Tests of eye and optic nerve cells found the protein enabled significant regeneration weeks after a crush injury to the optic nerve. The research demonstrated almost complete protection of nerve cells from a mouse retina growing in cell culture, a technique which would usually be expected to result in extensive cell death. Next steps are to explore the ability of protrudin to protect and regenerate human retinal cells.

New Longevity Focused Venture Funds Continue to Emerge
https://www.fightaging.org/archives/2020/11/new-longevity-focused-venture-funds-continue-to-emerge/

This article considers one newer venture fund that is focused on the growing longevity industry. It is far from the only such recently created fund; one might consider SP8CEVC and Longevitytech.fund as other examples. There are more. Biotech startups attempting to address mechanisms of aging are launched at a faster rate these days, and an increasing amount of capital is coming into the space. These are still the early years for this industry, but the trend is apparent. The thesis that one can intervene in the aging process to productively slow or reverse aging is going to be solidly tested in practice in the years ahead.

Not long after Deep Longevity, Inc was acquired by Regent Pacific, funding details have been revealed. First early-stage investment fund LongeVC is using this latest exit to create its first early-stage investment fund, which will be focused on biotech and Longevity opportunities. Deep Longevity closed a Series A funding round at the end of June 2020. LongeVC was joined in the round by some of the most worldwide well-known venture capitalists specialising in biotechnology, Longevity and AI, including ETP Ventures, Human Longevity and Performance Impact Venture Fund (the corporate venture arm of Human Longevity, Inc.), BOLD Capital Partners, Longevity Vision Fund, Oculus co-founder Michael Antonov, as well as other AI and biotechnology investors.

LongeVC is an investment group, specialising in curating, facilitating and executing early-stage venture investments in the fields of biotech and Longevity. Its current investment portfolio includes Insilico Medicine, a global leader in AI-driven drug discovery and Longenesis, an end-to-end collaborative biotech research enabler, as well as other biotech industry-specific companies.

Addressing the Regent Pacific acquisition of Deep Longevity and his fund's exit, LongeVC Partner Sergey Jakimov told us: "Our team welcomes this acquisition and is proud to have participated in one of the testimonies to the enormous future potential that the longevity industry has to offer. It is a unique deal for the Baltic area, and we are determined to use our expertise to screen and invest in similar deals globally." Currently the new fund LongeVC is being set up, with the total amount of the money available from the fund estimated to be 35 million. "We are targeting seed-stage and pre-A funding round companies as there are limited opportunities worldwide to get investments at these stages."