Vasoactive Intestinal Peptide: Another Player in Adipose Tissue Blood Flow Regulation?

In healthy people, adipose tissue blood flow (ATBF) rises postprandially; however, in one third of them, this response is altered. These people are characterized by prolonged postprandial lipemia and higher cardiometabolic risk. Vasoactive intestinal peptide (VIP) is a gut neurotransmitter with a vasodilatory effect. The aim of the study was to assess the role of VIP in ATBF regulation and its postprandial blunting. Plasma VIP and ATBF (133Xenon washout technique) were measured during a 75 g oral glucose load in 16 healthy participants. ATBF was monitored in 12 individuals during in situ microinfusion of incremental doses of VIP (10-7, 10-6, 10-5 mol L-1). Oral glucose induced no change in plasma VIP. Post-glucose ATBF measures identified 7 non-responders (peak blood flow < 50% of fasting values) and 9 responders. Compared to baseline (2.50 [1.96-3.59] mL·100 g-1 min-1), local microinfusion of VIP increased ATBF dose-dependently: 2.67 [2.18-3.89]; 4.35 [3.33-4.65]; and 7.91 [6.59-9.88] mL·100 g-1 min-1 (p < 0.0001) with a non-significant lower response to VIP in non-responders. Our findings show a potent vasodilatory effect of VIP in adipose tissue and suggest that individuals with a blunted ATBF response to glucose load have a lower response. Whether the local unresponsiveness to VIP participates in this non-responder status has to be confirmed in larger studies.