title: Comparative study between microvascular tone regulation and rheological properties of blood in patients with type 2 diabetes mellitus.
abstract: The aim of the study is to investigate the changes of the skin blood flow responses to cold stress in patients with diabetes mellitus type 2 through wavelet analysis of the peripheral skin temperature oscillations and to estimate their relationship with the blood viscosity values. The amplitudes of the skin temperature pulsations (ASTP) were monitored by "Microtest" device ("FM-Diagnostics", Russia); the whole blood viscosity and the shear stresses were measured by Contraves LS30 viscometer (Switzerland) at a steady flow in 9 healthy subjects and in 30 patients with type 2 diabetes mellitus. Power law and Herschel-Bulkley (HB) equations were applied to describe the blood rheology. Both models include consistency (k) and flow index (m), and the HB also gives the yield stress (τ0). The Spearman rank correlations between these parameters and the ASTP in the frequency ranges, corresponding to the myogenic, neurogenic and endothelial mechanisms of the microcirculation tone regulation were calculated. The ASTP values decreased when the blood viscosity increased. The correlation analysis revealed good ASTP-m (r > 0.5) and ASTP-k (r < -0.5) relationships in the endothelial range, while the ASTP-τ0 correlation was weaker (r≈-0.4). These correlations became lower for the ASTP during the cold stress. The results prompt manifestation of endothelial dysfunction in patients with type 2 diabetes.
authors: Department of Biomechanics, Institute of Mechanics, Bulgarian Academy of Sciences, Sofia, Bulgaria.
authors: N
authors: N
authors: Antonova
authors: Department of Theoretical Physics, Perm State University, Perm, Russia.|Institute of Continuous Media Mechanics UB Russian Academy of Sciences, Perm, Russia.
authors: K
authors: K
authors: Tsiberkin
authors: Institute of Continuous Media Mechanics UB Russian Academy of Sciences, Perm, Russia.
authors: S
authors: S
authors: Podtaev
authors: Department of Biomechanics, Institute of Mechanics, Bulgarian Academy of Sciences, Sofia, Bulgaria.
authors: V
authors: V
authors: Paskova
authors: University Hospital of Neurology and Psychiatry "St. Naum", Medical University, Sofia, Bulgaria.
authors: I
authors: I
authors: Velcheva
authors: University Hospital of Neurology and Psychiatry "St. Naum", Medical University, Sofia, Bulgaria.
authors: N
authors: N
authors: Chaushev
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001809:Blood Viscosity / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D012212:Rheology
keywords: Diabetes mellitus type 2; blood viscosity; contralateral cold test; hemorheological equations; microcircular tone regulation; skin temperature oscillations