A State-of-the-Art Overview on (Epi)Genomics and Personalized Skin Rejuvenating Strategies.

This article aims to point out new perspectives opened by genomics and epigenomics in skin rejuvenation strategies which target the main hallmarks of the ageing. In this respect, this article presents a concise overview on: the clinical relevance of the most important clocks and biomarkers used in skin anti-ageing strategy evaluation, the fundamentals, the main illustrating examples preclinically and clinically tested, the critical insights on knowledge gaps and future research perspectives concerning the most relevant skin anti-ageing and rejuvenation strategies based on novel epigenomic and genomic acquisitions. Thus the review dedicates distinct sections to: senolytics(definition) and senomorphics targeting senescent skin cells and their senescent-associated phenotype; strategies targeting genomic instability and telomere(definition) attrition by stimulation of the deoxyribonucleic acid (DNA) repair enzymes and proteins essential for telomeres' recovery and stability; regenerative medicine based on mesenchymal stem cells or cell-free products in order to restore skin-resided stem cells; genetically and chemically induced skin epigenetic partial reprogramming(definition) by using transcription factors or epigenetic small molecule agents, respectively; small molecule modulators of DNA methylases, histone deacetylases, telomerases, DNA repair enzymes or of sirtuins; modulators of micro ribonucleic acid (miRNA) and long-non-coding ribonucleic acid (HOTAIR's modulators) assisted or not by CRISPR-gene editing technology (CRISPR: Clustered Regularly Interspaced Short Palindromic Repeats); modulators of the most relevant altered nutrient-sensing pathways in skin ageing; as well as antioxidants and nanozymes to address mitochondrial dysfunctions and oxidative stress. In addition, some approaches targeting skin inflammageing, altered skin proteostasis(definition), (macro)autophagy(definition) and intercellular connections, or skin microbiome, are very briefly discussed. The review also offers a comparative analysis among the newer genomic/epigenomic-based skin anti-ageing strategies vs. classical skin rejuvenation treatments from various perspectives: efficacy, safety, mechanism of action, evidence level in preclinical and clinical data and regulatory status, price range, current limitations. In these regards, a concise overview on senolytic/senomorphic agents, topical nutrigenomic pathways' modulators and DNA repair enzymes, epigenetic small molecules agents, microRNAs and HOTAIRS's modulators, is illustrated in comparison to classical approaches such as tretinoin and peptide-based cosmeceuticals, topical serum with growth factors, intense pulsed light, laser and microneedling combinations, chemical peels, botulinum toxin injections, dermal fillers. Finally, the review emphasizes the future research directions in order to accelerate the clinical translation of the (epi)genomic-advanced knowledge towards personalization of the skin anti-ageing strategies by integration of individual genomic and epigenomic profiles to customize/tailor skin rejuvenation therapies.