Editorial: Telomeres and Epigenetics in Endocrinology

Yiqiang Zhan, Huan Song
2019 Frontiers in Endocrinology  
Editorial on the Research Topic Telomeres and Epigenetics in Endocrinology Aging, the multifactorial process in which a progressive decline at the cellular, tissue, and organismal levels leads to death, has perpetually fascinated human beings around the world. In addition to the apparent signs of aging, such as gray hair, skin wrinkling, and muscle atrophy, other potential biological markers that are of predictive values still deserve to be determined. The most recent efforts on this topic have
more » ... on this topic have discovered two biomarkers that are of significance in the aging research field: telomeres and epigenetics (1). Telomeres are a repetitive sequence of nucleotides (TTAGGG) at the end of chromosomes. Since being discovered, they have been hypothesized as the fundamental aspect of cellular senescence. In particular, the length of telomeres gradually decreases as cells divide. In humans, the length of telomeres is ∼5,000-10,000 base pairs for newborns, which begins to decline at the rate of 20-40 base pairs/year. Accumulating evidence has found that shorter telomeres were associated with cardiovascular diseases (2-6), diabetes (7) , stroke (8), dementia and brain health (9-12), and mortality (13, 14) . However, the evidence for the roles of telomeres in endocrinology is not conclusive. For example, it is not clear if some biomarkers of endocrinology, such as vitamin D, peptides, insulin, and diabetes, and other glycemic traits are associated with telomeres and what the potential implications of these biomarkers and telomeres in the clinics of endocrinology and other clinical departments are. The same questions could also be applied to epigenetics, another aging biomarker. Epigenetics primarily represents the changes that affect the activity and expression of genes. These changes can result from environmental factors, such as smoking behavior and other exposures. Of note, is that epigenetic changes have been found to be associated with aging-related outcomes, and are also involved in endocrinology. However, more evidence is needed, and further elucidation of the biological mechanisms is warranted. With these knowledge gaps, we initiated the special topic collection and attracted these articles in the field of endocrinology of aging. In the first article, Yang et al. reported a study that examined the relationship of telomeres with C-peptide (Yang et al.) and found a negative/inverse association between longer telomeres and lower levels of C-peptide. C-peptide is a short polypeptide with 31-amino-acid and relates insulin's A-chain to its B-chain in the proinsulin molecule. It was first described in connection with the discovery of the insulin biosynthesis pathway half a century ago. In clinical settings, patients with diabetes may have their C-peptide levels measured to distinguish type 1 diabetes and type 2 diabetes. The study performed by Yang et al. made multivariate adjustments and controlled for a few other factors, including age and sex, and thus offered new evidence to support that telomeres are associated with glycemic traits, albeit with a small magnitude. The second article by Pavanello et al. presented a study that examined the interaction between obesity and locus at CYP27A1 (encoding sterol 27-hydroxylase, a largely distributed mitochondrial P450 cytochrome enzyme that converts extrahepatic cholesterol to 27-hydroxycholesterol) and
doi:10.3389/fendo.2019.00257 fatcat:ywmknhwmybccdcrkcobmbahdxm