Is Evidence Supporting the Subtelomere-Telomere Theory of Aging?

The consumption of Sechium edule (chayote) has antioxidant effect and prevents telomere attrition in older adults with metabolic syndrome

OBJECTIVE

To determine the effect of the consumption of Sechium edule (1.5 g/day) for six months on oxidative stress (OxS) and inflammation markers and its association with telomere length (TL) in older adults with metabolic syndrome (MetS).

METHODS

The study was conducted in a sample of 48 older adults: placebo (EP) and experimental (EG) groups. Lipoperoxides, protein carbonylation, 8-OHdG, total oxidant status (TOS), SOD, GPx, H₂O₂ inhibition, total antioxidant status (TAS), inflammatory cytokines (IL6, IL10, TNF-α), and TL were measured before and six months post-treatment.

RESULTS

We found a significant decrease in the levels of lipoperoxides, protein carbonylation, 8-OHdG, TOS in the EG in comparison PG. Likewise, a significante increase of TAS, IL-6, and IL-10 levels was found at six months post-treatment in EG in comparison with PG. TL showed a statistically significant decrease in PG compared to post-treatment EG.

CONCLUSIONS

Our findigns showed that the supplementation of Sechium edule has antioxidant, and anti-inflammatory effects, and diminushion of shortening of telomeric DNA in older adults with MetS. This would be the first study that shows that the intervention with Sechium edule has a possible geroprotective effect by preventing telomeres from shortening as usually happens in these patients. Therefore, suggesting a protection of telomeric DNA and genomic DNA.

Is Human Aging a Form of Phenoptosis?

A much debated question is whether aging is the cumulative consequence of degenerative factors insufficiently opposed by natural selection, or, on the contrary, an ordered process, genetically determined and regulated, modeled by natural selection, and for which the definition of phenoptotic phenomenon would be entirely appropriate. In this review, theoretical arguments and empirical data about the two hypotheses are exposed, with more evidence in support of the thesis of aging as a form of phenoptosis. However, as the thesis of aging as an adaptive and programmed phenomenon necessarily requires the existence of specific mechanisms that determine to age, such as the subtelomere-telomere theory proposed for this purpose, the evidence supporting the mechanisms described by this theory is reported. In particular, it is highlighted that the recent interpretation of the role of TERRA sequences in the context of subtelomere-telomere theory is a fundamental point in supporting the hypothesized mechanisms. Furthermore, some characteristics of the mechanisms proposed by the theory, such as epigenetic modifications in aging, gradual cell senescence, cell senescence, limits in cell duplications, and fixed size of the telomeric heterochromatin hood, are exposed in their compatibility with both the thesis of aging as phenoptotic phenomenon and the opposite thesis. In short, aging as a form of phenoptosis appears a scientifically sound hypothesis while the opposite thesis should clarify the meaning of various phenomena that appear to invalidate it.

Immunosenescence and Altered Vaccine Efficiency in Older Subjects: A Myth Difficult to Change

Organismal ageing is associated with many physiological changes, including differences in the immune system of most animals. These differences are often considered to be a key cause of age-associated diseases as well as decreased vaccine responses in humans. The most often cited vaccine failure is seasonal influenza, but, while it is usually the case that the efficiency of this vaccine is lower in older than younger adults, this is not always true, and the reasons for the differential responses are manifold. Undoubtedly, changes in the innate and adaptive immune response with ageing are associated with failure to respond to the influenza vaccine, but the cause is unclear. Moreover, recent advances in vaccine formulations and adjuvants, as well as in our understanding of immune changes with ageing, have contributed to the development of vaccines, such as those against herpes zoster and SARS-CoV-2, that can protect against serious disease in older adults just as well as in younger people. In the present article, we discuss the reasons why it is a myth that vaccines inevitably protect less well in older individuals, and that vaccines represent one of the most powerful means to protect the health and ensure the quality of life of older adults.