Skin, as the outermost organ of the body, is constantly exposed to both intrinsic and extrinsic causative factors of aging. Intrinsic aging is related to compromised cellular proliferative capacity, and may be accelerated by harmful environmental influences with the greatest significance of ultraviolet radiation exposure, contributing not only to premature aging, but also to skin carcinogenesis. The overall skin cancer burden and steadily increasing global antiaging market provide an incentive for searching novel targets to improve skin resistance against external injury. Sirtuin 1, initially linked to extension of yeast and rodent lifespan, plays a key role in epigenetic modification of proteins, histones, and chromatin by which regulates the expression of genes implicated in the oxidative stress response and apoptosis. The spectrum of cellular pathways regulated by sirtuin 1 suggests its beneficial impact on skin aging. However, the data on its role in carcinogenesis remains controversial. The aim of this review was to discuss the relevance of sirtuin 1 in skin aging, in the context of intrinsic factors, related to genetic premature aging syndromes, as well as extrinsic modifiable ones, with the assessment of its future application. PubMed were searched from inception to 4 January 2021 for relevant papers with further search carried out on ClinicalTrials.gov. The systematic review included 46 eligible original articles. The evidence from numerous studies proves sirtuin 1 significance in both chronological and premature aging as well as its dual role in cancer development. Several botanical compounds hold the potential to improve skin aging symptoms.

Renalase, secreted by the kidney, degrades catecholamines and may play a role in the regulation of sympathetic tone and blood pressure. The aim of this study was to assess serum renalase levels in hemodialysis patients and their relationship to blood pressure control, type of antihypertensive therapy and the presence of residual renal function. Results: The mean serum renalase in the study cohort was significantly higher than in the control group (27.53 ± 7.18 vs. 3.86 ± 0.73 µg/ml, p < 0.001). The serum renalase concentration was significantly lower in patients with residual renal function when compared to the anuric patients. The type of hypotensive treatment (β-blockers, ACE inhibitors or AT1 receptor blockers) did not affect renalase levels. There was a significant inverse correlation between the serum renalase and age (r = –0.28, p = 0.023) and residual renal function (r = –0.327, p = 0.001). Renalase was not related to blood pressure, heart rate or hemodialysis vintage. Conclusion: Elevated renalase levels in HD patients may be due to impaired kidney function. Further studies are needed to prove or disprove the possible role of renalase in the pathogenesis of hypertension in patients with kidney diseases.

Renalase is an enzyme released by the kidneys, which breaks down catecholamines in the blood and thus may regulate blood pressure. In kidney transplant recipients, endothelial dysfunction is often present. The aim of the study was to assess associations between renalase, blood pressure, and kidney function in kidney allograft recipients. We studied 62 kidney allograft recipients. Complete blood count, urea and creatinine levels, serum lipids, and fasting glucose were measured by standard laboratory methods. We also assessed markers of coagulation: prothrombin fragments 1+2; fibrinolysis: tissue plasminogen activator (tPA), plasminogen activator inhibitor, plasmin-antiplasmin complexes; endothelial function/injury: von Willebrand factor (vWF), thrombomodulin, intercellular adhesion molecule, vascular cell adhesion molecule (VCAM); and inflammation: high‑sensitivity C‑reactive protein and interleukin 6. Renalase levels were assessed using a commercially available kit. Mean serum renalase levels in kidney allograft recipients correlated with age, time after transplantation, soluble CD44 (sCD44), VCAM, serum creatinine, estimated glomerular filtration rate (eGFR; measured by CKD-EPI, MDRD, and Cockcroft‑Gault formulas), serum phosphate, urea, sCD146, vWF, and thrombomodulin and tended to correlate with tPA. In patients with eGFR above 60 ml/min, renalase was lower than in those with lower eGFR. In hypertensive allograft recipients, renalase was significantly higher than in normotensives. A multiple regression analysis showed that renalase was predicted in 58% by serum creatinine. Renalase, which is highly elevated in kidney transplant recipients, is dependent primarily on kidney function, which deteriorates with age and time after transplantation. Further studies are needed to establish the putative role of renalase in the pathogenesis of hypertension after transplantation and its possible use in novel targeted therapies.

Introduction: Hypertension and kidney disease have been associated with increased incidence of stroke. Renalase, a newly discovered hormone, is secreted by the kidney and circulates in blood. The aim of this study was to assess possible correlations between renalase, blood pressure, stroke, and cardiovascular status in prevalent hemodialyzed patients. Methods: Renalase was assessed using commercially available assay. Echocardiography was performed in each patient. Results: Serum renalase was significantly lower in patients with a history of stroke (21%) than in patients without it. Similarly, renalase was significantly lower in hypertensive patients (82%) when compared with normotensives. Serum renalase correlated with creatinine, residual renal function, and transferrin saturation. The only predictor of renalase in multiple regression analysis was the presence of hypertension explaining 90% of the renalase variations. Conclusions: Our preliminary results suggest that renalase, probably due to the sympathetic nervous system hyperactivity, could be associated with hypertension and cardiovascular complications, including stroke in hemodialyzed patients. However, further studies are needed to establish the possible role of renalase in these complications. Renalase is “a new postulated therapeutic target.”