Histological Skin Assessment of Patients Submitted to Bariatric Surgery: A Prospective Longitudinal Cohort Study

Background Obesity is a stigmatizing disease that can cause dermatological aberrations, such as sagging after rapid weight loss. Objective This study is to evaluate the effects of obesity and massive weight loss following bariatric surgery on collagen and elastic fibers of the extracellular matrix of the skin. Methods Thirty-three skin biopsies were collected from patients prior to bariatric surgery and one year after surgery. Histological analyses were performed using hematoxylin-eosin and Weigert’s resorcin-fuchsin staining for collagen and elastic and elaunin fibers, respectively. Differences between means were submitted to the Student’s t -test or Mann-Whitney U test, with p < 0.05 significant. Results The study demonstrated an architectural alteration of the skin 1 year after bariatric surgery. In the histological analysis of the skin samples, a significant difference in the thickness of the epidermis was found 1 year after surgery in all age groups as well as in the 38-to-68-kg weight loss group ( p < 0.0001). In addition to laxity, disorganization of collagen was found, with an apparent decrease in quantity and an increase in elastic fibers, although fragmented ( p < 0.0001). Conclusion Obesity and massive weight loss following bariatric surgery cause the disorganization of collagen fibers and the fragmentation of elastic fibers of the extracellular matrix of the skin. Graphical Abstract