Elevated Serum Leptin Receptor and Insulin-like Growth Factor-1 Levels and High Levels of Leptin Receptor Expression in Acanthosis Nigricans Patients: Serologic and Histopathologic Analyses

Abstract

Background: Acanthosis nigricans is characterized by a velvety thickening of the epidermis accompanied by different degrees of hyperpigmentation, and known to be linked to obesity and insulin resistance.

Objective: We aimed to analyze obesity-related factors in acanthosis nigricans patients and to evaluate the correlations between acanthosis nigricans and various factors.

Methods: From January 2004 to February 2015, 27 acanthosis nigricans patients participated in this study. Blood samples were collected from a control group of seven overweight people and from the seven acanthosis nigricans patients, and they were analyzed for different obesity-related factors. Skin samples were collected from the 23 acanthosis nigricans patients and from 11 patients with epidermal nevi, and immunohistochemistry was performed to detect the presence of adiponectin receptor 1, adiponectin receptor 2, and the leptin receptor.

Results: The median serum leptin level in the acanthosis nigricans patients (13 ng/mL) was significantly higher than that in the overweight control individuals (8.9 ng/mL) (p=0.021). The acanthosis nigricans patients had significantly higher levels of insulin-like growth factor-1 in their serum samples (p=0.017). The immunohistochemical analysis determined that the skin from the acanthosis nigricans patients stained significantly more intensely for the leptin receptor compared with that seen in the skin from the patients with epidermal nevi (p=0.002).

Conclusion: In conclusion, this study's findings suggest that the levels of leptin and insulin-like growth factor-1 in the serum, and the expression of the leptin receptor in the skin are elevated with acanthosis nigricans.