Visfatin expression analysis in association with recruitment and activation of human and rodent brown and brite adipocytes

Description

Human brown adipocytes are able to burn fat and glucose and are now considered as a potential strategy to treat obesity, type 2 diabetes and metabolic disorders. Besides their thermogenic function, brown adipocytes are able to secrete adipokines. One of these is visfatin, a nicotinamide phosphoribosyltransferase involved in NAD synthesis, known to participate in insulin synthesis by pancreatic β cells. In a therapeutic context, it is of interest to establish whether a potential correlation exists between brown adipocyte activation and/or brite adipocyte recruitment, and adipokine expression. We analyzed visfatin expression, as a prerequisite to its secretion, in rodent and human biopsies and cell models of brown/brite adipocytes. We found that visfatin was preferentially expressed in mature adipocytes and that this expression is higher in brown adipose tissue of rodents compared to other fat depots. However, using various rodent models we were unable to find any correlation between visfatin expression and brown or brite adipocyte activation or recruitment. Interestingly, the situation is different in humans, where visfatin expression was found equivalent between white and brown or brite adipocyte in vivo and in vitro. In conclusion, visfatin can be considered only as a rodent brown adipocyte biomarker, independently to tissue activation.

Abstract

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