Novel Adipokine Links Obesity and Metabolic Syndrome
Dipeptidyl peptidase 4 linked to adipocyte size, volume, and to metabolic syndrome parameters
WEDNESDAY, July 13 (HealthDay News) -- Dipeptidyl peptidase 4 (DPP4) is a novel adipokine that appears to be involved in linking adipose tissue and the metabolic syndrome, according to a study published in the July issue of Diabetes.
Daniela Lamers, from the German Diabetes Center Düsseldorf, and colleagues investigated the functional implications of adipokine DPP4 and its association to different parameters of metabolic syndrome. Release of DPP4 and effects of soluble DPP4 on insulin signaling were assessed using human adipocytes, and skeletal and smooth muscle cells. Depot-specific expression of DPP4 and its release from adipose tissue explants were determined and correlated to parameters of the metabolic syndrome in both obese and lean participants.
The investigators found a substantially higher release of DPP4 in fully differentiated adipocytes than in preadipocytes and macrophages. Insulin signaling was impaired with direct addition of DPP4 to fat, and skeletal and smooth muscle cells. Visceral fat had a five-fold higher DPP4 protein expression than subcutaneous fat in obese patients, while lean patients had no such regional difference. Serum DPP4 concentrations were significantly associated with adipocyte size. In both obese and lean participants, a two-fold increase in DPP4 release was strongly associated with adipocyte volume and all parameters of the metabolic syndrome, and decreased to lean level following weight reduction. There was a positive correlation between DPP4 released from adipose tissue and increase in risk score for the metabolic syndrome.
"DPP4 is a novel adipokine that is substantially over-expressed in visceral fat from obese subjects and exhibits an augmented release in obesity," the authors write.