A mid-life crisis for aging theory

Resveratrol, Potential Therapeutic Interest in Joint Disorders: A Critical Narrative Review

Trans-resveratrol (t-Res) is a natural compound of a family of hydroxystilbenes found in a variety of spermatophyte plants. Because of its effects on lipids and arachidonic acid metabolisms, and its antioxidant activity, t-Res is considered as the major cardioprotective component of red wine, leading to the “French Paradox” health concept. In the past decade, research on the effects of resveratrol on human health has developed considerably in diverse fields such as cancer, neurodegenerative and cardiovascular diseases, and metabolic disorders. In the field of rheumatic disorders, in vitro evidence suggest anti-inflammatory, anti-catabolic, anti-apoptotic and anti-oxidative properties of t-Res in various articular cell types, including chondrocytes and synoviocytes, along with immunomodulation properties on T and B lymphocytes. In preclinical models of osteoarthritis and rheumatoid arthritis, resveratrol has shown joint protective effects, mainly mediated by decreased production of pro-inflammatory and pro-degradative soluble factors, and modulation of cellular and humoral responses. Herein, we comprehensively reviewed evidence supporting a potential therapeutic interest of t-Res in treating symptoms related to rheumatic disorders.

Classifying aging as a disease in the context of ICD-11

Aging is a complex continuous multifactorial process leading to loss of function and crystalizing into the many age-related diseases. Here, we explore the arguments for classifying aging as a disease in the context of the upcoming World Health Organization's 11th International Statistical Classification of Diseases and Related Health Problems (ICD-11), expected to be finalized in 2018. We hypothesize that classifying aging as a disease with a "non-garbage" set of codes will result in new approaches and business models for addressing aging as a treatable condition, which will lead to both economic and healthcare benefits for all stakeholders. Actionable classification of aging as a disease may lead to more efficient allocation of resources by enabling funding bodies and other stakeholders to use quality-adjusted life years (QALYs) and healthy-years equivalent (HYE) as metrics when evaluating both research and clinical programs. We propose forming a Task Force to interface the WHO in order to develop a multidisciplinary framework for classifying aging as a disease with multiple disease codes facilitating for therapeutic interventions and preventative strategies.

Optimization of trans-Resveratrol bioavailability for human therapy

We have developed an innovative soluble galenic form to overcome the low absorption of trans-Resveratrol (t-Res) as a dry powder. We present here data on pharmacokinetics, bioavailability, and toxicity of t-Res in human volunteers treated with this soluble form, plus additional data on biological effects in rodents. Fifteen healthy volunteers of both sexes received 40 mg of t-Res in two forms, the soluble formulation (caplets) and the original powder (capsules), in a crossover design. Blood samples were collected at 15 min, 30 min, and every hour for 5 h. Plasma concentrations of t-Res and its metabolites were analyzed by liquid chromatography and mass spectrometry. The single dose (40 mg) of the soluble t-Res was well absorbed and elicited biologically efficient blood levels (0.1-6 μM) for several hours, despite metabolization into glucuronide and sulfate conjugates coupled to renal elimination. In contrast, t-Res administered as a dry powder barely elicited efficient blood levels for a short duration. The new formulation led to 8.8-fold higher t-Res levels in plasma versus the powder. t-Res metabolism was not modified and neither intolerance nor toxicity were observed during the study and the following week. The soluble formulation elicited a robust anti-inflammatory effect in various tissues of mice fed a high-fat diet, while dry powder t-Res was almost inactive. Our data suggest that significant improvements in t-Res bioavailability and efficiency can be obtained by this soluble galenic form, also allowing lower doses. The use of t-Res in human therapy is thus greatly facilitated and the toxicity risk is reduced.

Absence of effects of Sir2 overexpression on lifespan in C. elegans and Drosophila

Overexpression of sirtuins (NAD(+)-dependent protein deacetylases) has been reported to increase lifespan in budding yeast (Saccharomyces cerevisiae), Caenorhabditis elegans and Drosophila melanogaster. Studies of the effects of genes on ageing are vulnerable to confounding effects of genetic background. Here we re-examined the reported effects of sirtuin overexpression on ageing and found that standardization of genetic background and the use of appropriate controls abolished the apparent effects in both C. elegans and Drosophila. In C. elegans, outcrossing of a line with high-level sir-2.1 overexpression abrogated the longevity increase, but did not abrogate sir-2.1 overexpression. Instead, longevity co-segregated with a second-site mutation affecting sensory neurons. Outcrossing of a line with low-copy-number sir-2.1 overexpression also abrogated longevity. A Drosophila strain with ubiquitous overexpression of dSir2 using the UAS-GAL4 system was long-lived relative to wild-type controls, as previously reported, but was not long-lived relative to the appropriate transgenic controls, and nor was a new line with stronger overexpression of dSir2. These findings underscore the importance of controlling for genetic background and for the mutagenic effects of transgene insertions in studies of genetic effects on lifespan. The life-extending effect of dietary restriction on ageing in Drosophila has also been reported to be dSir2 dependent. We found that dietary restriction increased fly lifespan independently of dSir2. Our findings do not rule out a role for sirtuins in determination of metazoan lifespan, but they do cast doubt on the robustness of the previously reported effects of sirtuins on lifespan in C. elegans and Drosophila.

α-Tocotrienol quinone modulates oxidative stress response and the biochemistry of aging

We report that α-tocotrienol quinone (ATQ3) is a metabolite of α-tocotrienol, and that ATQ3 is a potent cellular protectant against oxidative stress and aging. ATQ3 is orally bioavailable, crosses the blood-brain barrier, and has demonstrated clinical response in inherited mitochondrial disease in open label studies. ATQ3 activity is dependent upon reversible 2e-redox-cycling. ATQ3 may represent a broader class of unappreciated dietary-derived phytomolecular redox motifs that digitally encode biochemical data using redox state as a means to sense and transfer information essential for cellular function.

Control of redox state and redox signaling by neural antioxidant systems

The glutathione/glutathione disulfide (GSH/GSSG) redox pair forms the major redox couple in cells and as such plays a critical role in regulating redox-dependent cellular functions. Not only does GSH act as an antioxidant but it can also modulate the activity of a variety of different proteins. An impairment in GSH status is thought to be the precipitating event in a wide range of neurological disorders. Therefore, understanding how to maintain GSH in the CNS could provide a valuable therapeutic approach. Intracellular GSH levels are regulated by a complex series of pathways that include substrate transport and availability, rates of synthesis and regeneration, GSH utilization, and GSH efflux. To date, the most effective approaches for maintaining GSH levels in the CNS include enhancing cyst(e)ine uptake both directly and indirectly via transcriptional upregulation of system x(c)(-), increasing GSH synthesis via transcriptional upregulation of the rate limiting enzyme in GSH biosynthesis, and decreasing GSH utilization. Among the transcription factors that play critical roles in GSH metabolism are NF-E2-related factor 2 (Nrf2) and activating transcription factor 4 (ATF4). Thus, compounds that can upregulate these transcription factors may be particularly useful in promoting the functional maintenance of the CNS through their effects on GSH metabolism.

SIRT1: recent lessons from mouse models

The family of protein deacetylases represented by yeast Sir2 has been the focus of intense investigation because of the longevity activity of Sir2 in yeast, worms and flies. Research in mammals has mainly focused on SIRT1, the closest homologue of Sir2. Emerging evidence from mouse models is yielding a sharper picture, in which SIRT1 is a potent protector from ageing-associated pathologies, such as diabetes, liver steatosis, cardiovascular disease, neurodegeneration and, importantly, various types of cancer.

Dietary, metabolic, and potentially environmental modulation of the lysine acetylation machinery

Healthy lifestyles and environment produce a good state of health. A number of scientific studies support the notion that external stimuli regulate an individual's epigenomic profile. Epigenetic changes play a key role in defining gene expression patterns under both normal and pathological conditions. As a major posttranslational modification, lysine (K) acetylation has received much attention, owing largely to its significant effects on chromatin dynamics and other cellular processes across species. Lysine acetyltransferases and deacetylases, two opposing families of enzymes governing K-acetylation, have been intimately linked to cancer and other diseases. These enzymes have been pursued by vigorous efforts for therapeutic development in the past 15 years or so. Interestingly, certain dietary components have been found to modulate acetylation levels in vivo. Here we review dietary, metabolic, and environmental modulators of the K-acetylation machinery and discuss how they may be of potential value in the context of disease prevention.

Sirt1 improves healthy ageing and protects from metabolic syndrome-associated cancer

Genetic overexpression of protein deacetylase Sir2 increases longevity in a variety of lower organisms, and this has prompted interest in the effects of its closest mammalian homologue, Sirt1, on ageing and cancer. We have generated transgenic mice moderately overexpressing Sirt1 under its own regulatory elements (Sirt1-tg). Old Sirt1-tg mice present lower levels of DNA damage, decreased expression of the ageing-associated gene p16(Ink4a), a better general health and fewer spontaneous carcinomas and sarcomas. These effects, however, were not sufficiently potent to affect longevity. To further extend these observations, we developed a metabolic syndrome-associated liver cancer model in which wild-type mice develop multiple carcinomas. Sirt1-tg mice show a reduced susceptibility to liver cancer and exhibit improved hepatic protection from both DNA damage and metabolic damage. Together, these results provide direct proof of the anti-ageing activity of Sirt1 in mammals and of its tumour suppression activity in ageing- and metabolic syndrome-associated cancer.