Obese individuals may have fewer Wrinkles…If they don’t go out in the Sun

–Photo-aging is caused by cumulative chronic Ultraviolet (UV) exposure. It caused deep wrinkles and poikiloderma, which is characterized by dyschromia (leucomelanoderma: hypo pigmented and hyper pigmented areas), telangiectasia (broken blood vessels) and skin atrophy.
-It is different from normal aging where wrinkles are fine and there are fewer other features.

-The skin atrophy component of photo-aging clearly appear to be due to effects of Ultraviolet irradiation but the effect on the dermis is indirect through inhibition of Fat signaling molecules (Adipokines) in the hypodermis (Subcutaneous layer). These act like a “youth maintenance” signal to the dermis.

Please see the abstract below (Study from Seoul, South Korea)

Abstract
-Ultraviolet (UV) exposure to the human skin reduces triglyceride content and lipid synthesis in the subcutaneous fat (SC). Because adiponectin and leptin are the most abundant adipokines from the SC fat, we aim to investigate how they interact with UV exposure and skin aging.
-The expression of adiponectin and leptin were significantly decreased in SC fat of sun-exposed forearm skin, in comparison with that of sun-protected buttock skin of the same elderly individuals, indicating that chronic UV exposure  decreases both adipokines.
–Acute UV irradiation also decreased the expressions of adiponectin and leptin in SC fat. The expressions of adiponectin receptor 1 and 2 and leptin receptor were significantly decreased in the dermis as well as SC fat.
-Moreover, while exogenous adiponectin and leptin administration prevented UV- and TNF alpha induced matrix metalloproteinase (MMP)-expression, they also increased UV- and TNF alpha induced reduction of type 1 pro collagen production.
-Silencing of adiponectin, leptin or they receptors led to an increased MMP-1 and a decreased type 1 procollagen expression, which was reversed by treatment with recombinant human adiponectin or leptin.
-In conclusion, UV exposure decreases the expression of adiponectin and leptin, leading to the exacerbation of photo aging by stimulating MMP-1 expression and inhibiting procollagen synthesis.

P12-08. Ultraviolet irradiation induced inhibition of adipokine production in subcutaneous fat aggravates dermal matrix degradation in human skin Kim EJ et al. * Japanese Society for Investigative Dermatology 2016 – Sendai. Japan