Healthy Aging Research
Open Access

Age-related Biomarkers and Their Applications

Chukwuma Okoye^{* *}Correspondence: Chukwuma Okoye, Department of Clinical and Experimental Medicine, University Hospital of Pisa, Pisa, Italy, Email:

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Description

In contrast to chronological age, biomarkers of aging are signs that may be better able to predict functional capacity at a later age. In other words, aging biomarkers would reveal the true "biological age," which may not correspond to chronological age. Even though hair greying becomes more pronounced as we age, it cannot be considered a biomarker of aging. Similar to chronological age, skin wrinkles and other typical aging changes do not serve as superior predictors of future functionality.

Although efforts to identify and validate aging-related biomarkers have persisted, results have been inconsistent. The number of CD4 and CD8 memory T cells as well as naive T cells has been used to reliably predict the lifespan of middle-aged mice.

Epigenetic marks

Loss of histones: The loss of histones has been identified as a novel epigenetic marker in investigations of aging cells. The majority of the research indicates a connection between histone loss and cell division. Certain chromatin structures, such as fuzziness in nuclear positioning, a lack of a nucleosome depleted region at the promoter, weak chromatin phasing, a higher frequency of Goldberg–Hogness elements, and higher occupancy of repressive chromatin factors, are present in younger cells for the genes that are most induced with aging. However, nucleosome degradation at the promoter of the same genes is more common in older cells, which increases the transcription of these genes.

This behavior has also been observed in aged worms, human diploid primary fibroblasts, and senescent human cells in addition to yeast. Shortened telomeres, which trigger the DNA damage response, were found to be a consequence of diminished histone production in human primary fibroblasts. A common epigenetic indicator of aging in many species may be the loss of core histones.

Histone variants: There are various forms of the histone proteins that can be significantly different in their sequence from the core histones, H2A, H2B, H3, and H4, and which are crucial for controlling chromatin dynamics.

A histone H3 variation called histone H3.3 inserts itself into the genome without the need for replication. It appears that an excess of H3.3 can cause senescence because it is the main type of histone H3 found in the chromatin of senescent human cells.

Histone 2 comes in a variety of forms, but macroH2A is the one that has been most prominently linked to aging. For the most part, it has been considered that the role of macroH2A is transcriptional silencing; however, more recently, it has been proposed that macroH2A plays a crucial role in inhibiting transcription at Senescence-Associated Heterochromatin Foci (SAHF). The binding of transcription factors and ATPdependent remodeling proteins cannot bind to macroH2Acontaining chromatin.

Applications of aging biomarkers

Histone modification, histone loss, and DNA methylation have all been noted as potential biomarkers of aging. Identifying a physical characteristic of biological aging would enable humans to ascertain their true age, mortality, and morbidity. Biomarkers of aging have a wide range of applications.

The age of the species should alter proportionally to the change in the physical biomarker. Therefore, once a biomarker of aging has been identified, researchers can focus on expanding human life spans and determining when potential genetic diseases might first manifest.

This discovery could be used, among other things, to determine a person's biological age. Age can be calculated via DNA methylation by looking at the structure of DNA at various life stages. Cysteine in the CG or Cpg region of DNA is methylated when it is subjected to methylation.

Hypo methylation is related with increased transcriptional activity, while hyper methylation is the opposite. In other words, the more stable and "younger" the species, the more "tightly" held the DNA region is. When DNA methylation in tissues was examined, it was discovered that embryonic tissues had essentially little DNA methylation. This finding can be used to estimate age acceleration, and the findings can be replicated in chimpanzee tissue.