Telomerase activation in the treatment of aging or degenerative diseases: a systematic review

Understanding cellular senescence: pathways involved, therapeutics and longevity aiding

A normal somatic cell undergoes cycles of finite cellular divisions. The presence of surveillance checkpoints arrests cell division in response to stress inducers: oxidative stress from excess free radicals, oncogene-induced abnormalities, genotoxic stress, and telomere attrition. When facing such stress when undergoing these damages, there is a brief pause in the cell cycle to enable repair mechanisms. Also, the nature of stress determines whether the cell goes for repair or permanent arrest. As the cells experience transient or permanent stress, they subsequently choose the quiescence or senescence stage, respectively. Quiescence is an essential stage that allows the arrested/damaged cells to go through appropriate repair mechanisms and then revert to the mainstream cell cycle. However, senescent cells are irreversible and accumulate with age, resulting in inflammation and various age-related disorders. In this review, we focus on senescence-associated pathways and therapeutics understanding cellular senescence as a cascade that leads to aging, while discussing the recent details on the molecular pathways involved in regulating senescence and the benefits of therapeutic strategies against accumulated senescent cells and their secretions.

Ovarian rescue in women with premature ovarian insufficiency: facts and fiction

The ovary has a comparatively short functional lifespan compared with other organs, and genetic and pathological injuries can further shorten its functional life. Thus, preserving ovarian function should be considered in the context of women with threats to ovarian reserve, such as ageing, premature ovarian insufficiency (POI) and diminished ovarian reserve (DOR). Indeed, one-third of women with POI retain resting follicles that can be reactivated to produce competent oocytes, as proved by the in-vitro activation of dormant follicles. This paper discusses mechanisms and clinical data relating to new therapeutic strategies using ovarian fragmentation, stem cells or platelet-rich plasma to regain ovarian function in women of older age (>38 years) or with POI or DOR. Follicle reactivation techniques show promising experimental outcomes and have been successful in some cases, when POI is established or DOR diagnosed; however, there is scarce clinical evidence to warrant their widespread clinical use. Beyond these contexts, also discussed is how new insights into the biological mechanisms governing follicular dynamics and oocyte competence may play a role in reversing ovarian damage, as no technique modifies oocyte quality. Additional studies should focus on increasing follicle number and quality. Finally, there is a small but important subgroup of women lacking residual follicles and requiring oocyte generation from stem cells.

Investigational drugs and nutrients for human longevity. Recent clinical trials registered in ClinicalTrials.gov and clinicaltrialsregister.eu

Introduction:Several pharmacological drugs have shown proof of concept for longevity in animal models. I aimed to identify and review those longevity drug candidates that are undergoing clinical trials.Areas covered:Recent (post-2017) longevity clinical trials were found in US and EU clinical trial registries. Longevity drug candidates are the antidiabetic drugs metformin and acarbose, and the immunosuppressant rapamycin. These medicinal drugs are tested on biochemical and clinical markers of aging. In addition, vitamin D supplementation is being investigated in two mega-trials (sample size> 5000) for its efficacy in reducing all-cause mortality.Expert opinion:Anti-aging effects of longevity drug candidates suggest, but do not demonstrate that they prolong life. The two megatrials with vitamin D supplementation make it possible to detect differences in life expectancy between vitamin D and placebo. Therefore, a protocol similar to that for vitamin D could be used to demonstrate pro-longevity effects of metformin, acarbose, and rapamycin.

Telomere Length as a Marker of Biological Age: State-of-the-Art, Open Issues, and Future Perspectives

Telomere shortening is a well-known hallmark of both cellular senescence and organismal aging. An accelerated rate of telomere attrition is also a common feature of age-related diseases. Therefore, telomere length (TL) has been recognized for a long time as one of the best biomarkers of aging. Recent research findings, however, indicate that TL per se can only allow a rough estimate of aging rate and can hardly be regarded as a clinically important risk marker for age-related pathologies and mortality. Evidence is obtained that other indicators such as certain immune parameters, indices of epigenetic age, etc., could be stronger predictors of the health status and the risk of chronic disease. However, despite these issues and limitations, TL remains to be very informative marker in accessing the biological age when used along with other markers such as indices of homeostatic dysregulation, frailty index, epigenetic clock, etc. This review article is aimed at describing the current state of the art in the field and at discussing recent research findings and divergent viewpoints regarding the usefulness of leukocyte TL for estimating the human biological age.