Assessment of endothelial dysfunction in patients with impaired glucose tolerance during a cold pressor test

Abstract

The objective of this study is to explore changes in microvascular tone during a contralateral cold pressor test and to compare the results obtained in healthy subjects and in patients with impaired glucose tolerance (IGT) and type 2 diabetes. Low-amplitude fluctuations of skin temperature in the appropriate frequency ranges were used as a characteristic for the mechanism for vascular tone regulation. In total, 13 adults with type 2 diabetes aged 40-67 years and 18 adults with IGT aged 31-60 years participated in this pilot study. The control group included 12 healthy men and women aged 39-60 years. The response to the cold pressor test in patients with type 2 diabetes and with IGT differs essentially from that of healthy subjects in the endothelial frequency range. Endothelial dysfunction occurs in the preclinical stage of diabetes and manifests, in particular, as a disturbance of the endothelial part of vascular tone regulation.

Skin temperature variations as a tracer of microvessel tone

“…A relatively stable high correlation is observed for the frequencies corresponding to the endothelial mechanism. Note that ST measurements are most widely used today for diagnosing endothelial dysfunction [12,17].…”

“…spectral analysis of LDF signal has been performed using the fast Fourier transform [1], and wavelets were suggested to reproduce better the low-frequency range of LDF spectra [2,11]. Recently, high-resolution skin thermometry has been applied as an alternative indicator of the microcirculation functional state [12]. This technique is very attractive because it is cheap and easy to operate, although the use of temperature monitoring in vasomotion studies is not obvious.…”

The wavelet transform as a tool for the characterization of the vascular response in the human lower limb

“…A propriedade de localização das ôndulas torna a análise de ôndula capaz de analisar os sistemas não-estacionários e de detetar os parâmetros dinâmicos [7,8] . A wavelet Morlet, em particular, oferece uma boa resolução temporal em altas frequências e a melhor resolução de frequência para os componentes de baixa frequência [9] . As componentes mencionadas estão relacionados com várias atividades de regulação da perfusão -atividade cardíaca (de 0,6 Hz a 2 Hz), respiratória (de 0,15 Hz a 0,6 Hz), atividade miogénica na parede do vaso (de 0,052 Hz a 0,15 Hz), atividade simpática (de 0,021 Hz a 0,052 Hz) e atividade endotelial (mediada pelo óxido nítrico) (de 0,0095 Hz a 0.021 Hz) [10,11] .…”

“…The localization property of wavelets makes the wavelet analysis capable of analyzing the non-stationary systems and detecting dynamic parameters [7,8] . The Morlet wavelet, in particular, provides good time resolution at high frequencies and the best frequency resolution for low-frequency components [9] . The mentioned components are related to several perfusion-regulating activities -heart (0.6 Hz to 2 Hz), respiration (0.15 Hz to 0.6 Hz), myogenic activity in the vessel wall (0.052 Hz to 0.15 Hz), sympathetic activity (0.021 Hz to 0.052 Hz) and endothelial (nitric oxide-mediated) activity (0.0095 Hz to 0.021 Hz) [10,11] .…”

Role of myosin light chain and myosin light chain kinase in advanced glycation end product–induced endothelial hyperpermeability in vitro and in vivo

“…Increased vascular permeability due to impaired vascular endothelial cells structure and function is a major reason for vascular complications and a hallmark of DM. 1,2 High intracellular glucose leads to the formation of advanced glycation end products (AGEs) via non-enzymatic glycosylation of proteins, which have been shown to cross-link proteins, accelerate atherosclerosis, reduce nitric oxide synthesis and induce endothelial dysfunction. 3 Receptor for advanced glycation end product (RAGE) is the major receptor for AGEs.…”