CC BY
3*
ALT'23 The 30th International Conference on Advanced Laser Technologies
B-I-39
Effect of local heating on cutaneous hemodynamics regulation of upper and lower extremities in type 2 diabetes mellitus
Irina Tikhonova1, Irina Guseva2, Andrey Grinevich1, Arina Tankanag1
1-Institute of Cell Biophysics of Russian Academy of Sciences, Pushchino, Russia 2- Hospital of Pushchino Scientific Centre of Russian Academy of Sciences, Pushchino, Russia
The functioning of large central and small peripheral vessels is regulated by different physiological factors that determine peripheral hemodynamics. There are various non-invasive methods for monitoring peripheral microvasculature, among which laser Doppler flowmetry (LDF) and photoplethysmography (PPG) are the most accessible and popular. It is known that in type 2 diabetes mellitus (T2DM) thermoregulation is impaired, which may lead to decreased skin vasodilation of extremities due to the development of neurovascular dysfunction. Analysis of changes in mechanisms of skin hemodynamics regulation in response to local heating in T2DM patients may be an indicator of early microvascular dysfunction in noninvasive diagnosis. The aim was to assess changes in spectral components and phase relationships between tissue blood volume dynamics and skin blood flow oscillations in upper and lower extremities of healthy volunteers and T2DM patients in response to local heating.
Twenty-two T2DM patients (5 males and 17 females) and twenty-two healthy volunteers (8 males and 14 females) participated in the study. Measurement procedures were conducted in a quiet room at 23 ± 1°C after a 15-minute adaptation period. All subjects were in supine position during registration. Four 35-minute records were recorded simultaneously for each subject - tissue blood volume dynamics of the right index finger pad (PPGfg) and the right second toe pad (PPGtoe), as well as skin blood flow dynamics from the outer surface of the right forearm (LDFfm) and of the right foot (LDFft). The local heating was performed by heating both skin sites from 32 to 38 ^ in the area where LDF probes were placed. For each participant, two 15-minute fragments of the entire 35 min signals analyzed: the initial 15 minutes without heating (rest) and the last 15 minutes of probe (heating). Amplitude-frequency spectra were analyzed using adaptive wavelet transform, as well as phase interactions between pairs of analyzed signals were assessed by the value of wavelet phase coherence (WPC) function. Statistical analysis was performed using Wilcoxon tests for independent samples, significance differences were considered reliable at p < 0.05.
Amplitudes of respiratory oscillations (~ 0.3 Hz) of forearm blood flow (as measured by LDF) were higher at rest and during heating in patients versus healthy subjects. In comparison with controls the amplitudes of myogenic (~0.1 Hz) oscillations of foot blood flow were lower at rest and the amplitudes of cardiac (~1 Hz) oscillations - under local heating. No significant differences in spectral components of finger and toe tissue blood volume oscillations (as measured by PPG) were found between patients and healthy participants neither at rest nor under local heating. In patients WPC values for myogenic (~0.1 Hz) oscillations of LDFfm - LDFft and PPGfg - PPGtoe signal pairs were lower as compared to controls. The results obtained can provide the basis for development of methods for early noninvasive diagnosis of microvascular disorders and ways of their therapeutic correction in various socially significant diseases, including T2DM. This study was supported by the Russian Science Foundation [grant number # 22-15-00215].
