Perivascular fatty tissue at the brachial artery is linked to insulin resistance but not to local endothelial dysfunction

TY - JOUR

T1 - Perivascular fatty tissue at the brachial artery is linked to insulin resistance but not to local endothelial dysfunction

AU - Rittig, K

AU - Staib, K

AU - Machann, J

AU - Böttcher, M

AU - Peter, A

AU - Schick, F

AU - Claussen, C

AU - Stefan, N

AU - Fritsche, A

AU - Häring, H-U

AU - Balletshofer, B

PY - 2008/11/1

Y1 - 2008/11/1

N2 - AIMS/HYPOTHESIS: Different ectopic fat depots, such as visceral or hepatic fat, are known to affect whole body insulin sensitivity. It has recently been hypothesised that differences in perivascular adipose tissue (PVAT) mass around resistance vessels may also contribute to insulin resistance, possibly via direct vascular effects leading to reduced capillary cross-sectional area in the muscle, which in turn affects muscular blood flow and glucose uptake. Based on this, the aim of the present study was to test whether PVAT around conduit arteries (i.e. the brachial artery) influences NO bioavailability, expressed as flow-mediated dilation (FMD), or insulin sensitivity in humans in vivo.METHODS: Insulin sensitivity was measured by OGTT in all 95 participants (59 women, 36 men; median age 47 years, range 19-66 years) and by the gold standard, a euglycaemic-hyperinsulinaemic clamp, in a randomly selected subgroup of 33 participants. Quantification of the different fat compartments, including PVAT around the brachial artery, was achieved by high-resolution magnetic resonance imaging (1.5 T). Blood flow and FMD were measured at the brachial artery using high-resolution (13 MHz) ultrasound, after 5 min of forearm occlusion.RESULTS: PVAT was negatively correlated with insulin sensitivity and the post-ischaemic increase in blood flow. The association between PVAT and insulin sensitivity (r = -0.54, beta = -0.37, p = 0.009) was independent of age, sex, visceral adipose tissue, liver fat, BMI and further cardiovascular risk factors. No correlation could be detected between PVAT and local endothelial function. However, we observed an independent association between PVAT and post-ischaemic increase in blood flow (r = -0.241; beta = -1.69; p = 0.02).CONCLUSIONS/INTERPRETATION: PVAT seems to play an independent role in the pathogenesis of insulin resistance. This may be due to direct vascular effects influencing muscular blood flow.

AB - AIMS/HYPOTHESIS: Different ectopic fat depots, such as visceral or hepatic fat, are known to affect whole body insulin sensitivity. It has recently been hypothesised that differences in perivascular adipose tissue (PVAT) mass around resistance vessels may also contribute to insulin resistance, possibly via direct vascular effects leading to reduced capillary cross-sectional area in the muscle, which in turn affects muscular blood flow and glucose uptake. Based on this, the aim of the present study was to test whether PVAT around conduit arteries (i.e. the brachial artery) influences NO bioavailability, expressed as flow-mediated dilation (FMD), or insulin sensitivity in humans in vivo.METHODS: Insulin sensitivity was measured by OGTT in all 95 participants (59 women, 36 men; median age 47 years, range 19-66 years) and by the gold standard, a euglycaemic-hyperinsulinaemic clamp, in a randomly selected subgroup of 33 participants. Quantification of the different fat compartments, including PVAT around the brachial artery, was achieved by high-resolution magnetic resonance imaging (1.5 T). Blood flow and FMD were measured at the brachial artery using high-resolution (13 MHz) ultrasound, after 5 min of forearm occlusion.RESULTS: PVAT was negatively correlated with insulin sensitivity and the post-ischaemic increase in blood flow. The association between PVAT and insulin sensitivity (r = -0.54, beta = -0.37, p = 0.009) was independent of age, sex, visceral adipose tissue, liver fat, BMI and further cardiovascular risk factors. No correlation could be detected between PVAT and local endothelial function. However, we observed an independent association between PVAT and post-ischaemic increase in blood flow (r = -0.241; beta = -1.69; p = 0.02).CONCLUSIONS/INTERPRETATION: PVAT seems to play an independent role in the pathogenesis of insulin resistance. This may be due to direct vascular effects influencing muscular blood flow.

KW - Adipose Tissue

KW - Adult

KW - Aged

KW - Arm

KW - Blood Flow Velocity

KW - Blood Glucose

KW - Brachial Artery

KW - Diabetes Mellitus, Type 2

KW - Female

KW - Glucose Clamp Technique

KW - Glucose Tolerance Test

KW - Humans

KW - Hyperinsulinism

KW - Ischemia

KW - Liver

KW - Magnetic Resonance Imaging

KW - Male

KW - Middle Aged

KW - Vasodilation

U2 - 10.1007/s00125-008-1128-3

DO - 10.1007/s00125-008-1128-3

M3 - SCORING: Journal article

C2 - 18712517

VL - 51

SP - 2093

EP - 2099

JO - DIABETOLOGIA

JF - DIABETOLOGIA

SN - 0012-186X

IS - 11

ER -