Evidence for congruent impairment in micro and macrovascular function in type 1 diabetes

Abstract

Diabetes affects large and small vessels through mechanisms only partially known. In the present study, we evaluated the function of capillaries and large arteries in subjects with type 1 diabetes mellitus (T1DM) to study the effect of chronic hyperglycemia in the absence of other cardiovascular risk factors. Twenty-five subjects with T1DM and 12 healthy age-matched controls were enrolled. Nine patients had mild or moderate retinopathy. Contrast enhanced ultrasound was used to measure perfusion of the deep forearm flexor muscle of the non-dominant arm at rest (baseline) and after an ischemic stimulus (reactive hyperemia). Perfusion was expressed as Video Intensity (VI) in arbitrary unit (a.u.)/mm2. The time to reach peak VI after ischemia was also recorded. The function of large arteries was evaluated using flow-mediated vasodilation (FMD). VI was significantly lower in T1DM compared to control subjects both at baseline (0.22±0.16 vs 0.44±0.35 a.u./mm2, p<0.05), and after ischemia (0.33±0.24 vs 0.68±0.46 a.u./mm2, p<0.05). The time to reach peak VI after ischemia was markedly longer in T1DM (5.6±2.2 vs 4.0±1.7 seconds, p<0.02). These differences were more marked in T1DM subjects with retinopathy. FMD was lower in TIDM patients compared to controls (5.4±6.4 vs 10.7±4.5%, p<0.01). The present findings demonstrate that T1DM patients have defective peripheral skeletal muscle perfusion both at rest and after ischemia compared with control subjects. Low muscle perfusion associates with low FMD of the brachial artery. Furthermore, T1DM subjects with retinopathy have the least muscle perfusion and blunted response to hyperemia compared to T1DM without retinopathy.

Muscle fatigability in patients with type 2 diabetes: relation with long‐term complications

“…These findings are in line with a cross‐sectional investigation conducted in a cohort of T1DM patients reporting a strong association between retinopathy and reduced muscle strength and quality of the quadriceps muscles . A recent study has also reported that diabetic retinopathy is characterized by a more severe impairment of skeletal muscle perfusion at rest and after ischemia when compared with uncomplicated T1DM patients . Vascular dysfunction was proposed as the main mechanism underlying the loss of muscle performance in patients with retinopathy …”

“…A recent study has also reported that diabetic retinopathy is characterized by a more severe impairment of skeletal muscle perfusion at rest and after ischemia when compared with uncomplicated T1DM patients . Vascular dysfunction was proposed as the main mechanism underlying the loss of muscle performance in patients with retinopathy …”

Sympathoexcitation constrains vasodilation in the human skeletal muscle microvasculature during postocclusive reactive hyperemia

“…Heightened adrenergic vascular tone along with endothelial dysfunction (3,49,68) and structural remodeling of the microvasculature (25,29,42) contributes to the compromised vasodilatory ability seen in pathological states, such as diabetes mellitus and metabolic syndrome (23,24,44). A commonly used marker of vascular dysfunction is impaired postocclusive reactive hyperemia (PORH) (6,26,27,38,42,49). Frisbee (26) demonstrated in obese Zucker rats, a model of metabolic syndrome, that deteriorated PORH in cremaster muscle arterioles is significantly improved by ␣-adrenoreceptor blockade.…”

Utility of Contrast-Enhanced Ultrasound for the Assessment of Skeletal Muscle Perfusion in Diabetes Mellitus: A Meta-Analysis

“…However, Emanuel et al [29] found no correlation of peripheral insulin sensitivity with skeletal muscle MBV at baseline, or with MBV during hyperinsulinemia or with the percent change in MBV. Peripheral insulin sensitivity also did not significantly correlate with MBV during hyperinsulinemia and combined vasodilator (iloprost) infusion, or with the MBV percentage change induced by combined insulin and iloprost infusion in patients with type 2 diabetes.…”