visfatin

Visfatin is a protein that is also known as nicotinamide phosphoribosyltransferase (NAMPT) or pre-B cell colony-enhancing factor (PBEF). NAMPT is an enzyme that catalyzes the first step in the nicotinamide adenine dinucleotide (NAD) salvage pathway, converting nicotinamide to nicotinamide mononucleotide (NMN). Intracellular NAMPT is essential for cellular NAD+ biosynthesis and energy metabolism and is expressed in a wide range of tissues.

Extracellular NAMPT, sometimes referred to as visfatin, is secreted by visceral adipose tissue and immune cells. It has been proposed to act as an adipokine and proinflammatory cytokine. Early research suggested insulin-mimetic effects, but subsequent studies have not consistently demonstrated robust insulin-like activity, and a specific receptor or signaling mechanism for visfatin has not been definitively established.

In clinical research, circulating levels of visfatin/NAMPT have been reported to be elevated in obesity, insulin resistance, metabolic syndrome, and certain inflammatory states. However findings are heterogeneous, and elevated levels are not consistently observed across studies. As a result, visfatin is not currently considered a reliable biomarker for these conditions, and its role in disease remains a topic of ongoing investigation.

From a therapeutic perspective, NAMPT inhibitors such as FK866 (APO866) reduce cellular NAD+ and have shown anti-tumor activity in preclinical models, highlighting NAMPT’s central role in NAD+ metabolism. Their development is tempered by concerns about toxicity in normal tissues. Research continues into the diverse roles of visfatin/NAMPT in metabolism and inflammation.