Skin microcirculation reactivity to local thermal hyperaemia in patients with COVID-19 - A pilot observational study.

BACKGROUND: Endothelial dysfunction and microvascular disturbances are suggested to play a key role in higher morbidity and worse prognosis in patients with COVID-19 and cardiometabolic diseases. OBJECTIVE: Study was aimed to establish relationships between the skin microcirculation parameters and various clinical and laboratory indicators. METHODS: The study included 18 patients with moderate disease according to WHO criteria. Skin microcirculation measurements were performed by laser Doppler flowmetry using a heating test on the hairy skin of the right forearm. RESULTS: Baseline perfusion only correlated with C-reactive protein (Rs = 0.5, p = 0.034). Microcirculation indices characterising the development of hyperaemia during the first minute of heating (LTH1 and AUC60) showed significant correlations (Rs from 0.48 to 0.67, p < 0.05) with indices of general blood analysis and blood coagulation (fibrinogen, D-dimer, haemoglobin, erythrocyte count and haematocrit). Indexes characterising the dynamics of hyperaemia development over longer time intervals showed correlation with the glomerular filtration rate (Rs = 0.6, p = 0.009). CONCLUSION: Known COVID-19 risk factors (haemorheological parameters, age) are correlated with the microvascular reactivity to heating in patients with COVID 19. We suggest that, prospectively, the method of laser Doppler flowmetry could be used for non-invasive instrumental assessment of microcirculatory disorders in patients with COVID-19.

Reactivity of skin microcirculation as a biomarker of cardiovascular events. Pilot study.

BACKGROUND: The role of microcirculatory disorders is progressively being accepted in the pathogenesis of cardiovascular diseases. OBJECTIVE: The purpose of current study is to assess whether we can consider skin microcirculation disorders as a biomarker of cardiovascular events. METHODS: Group 1 consisted of healthy volunteers (n = 31); group 2 (n = 42) consisted of patients with diseases that increase the risk of cardiovascular events; group 3 (n = 39) included patients with the history of cardiovascular events. Skin microcirculation measurement was performed using laser Doppler flowmetry during the heating test. RESULTS: LDF parameters reflecting the rapid response of microcirculation to heating ("Slope 120 s" and "Slope 180 s") significantly differed in three groups (p <  0.05). A decrease in the "Slope 180 s" parameter less than 0.5 PU/s is associated with cardiovascular events (sensitivity 69.2%, specificity 66.7%; the area under the ROC curve, 0.667; 95% confidence interval [CI], 0.545-0.788, p = 0.01). Multivariable logistic regression analysis revealed that "Slope 180 s≤0.5 PU/s" was significantly related to cardiovascular events (adjusted odds ratio = 3.9, p = 0.019, CI 95% 1.2-12). CONCLUSIONS: Reduced reactivity of the skin microcirculation may be useful as a biomarker of severe damage to the cardiovascular system and is promising as a risk factor for cardiovascular events.

[Correlation of cutaneous blood microcirculation parameters with biological age in diabetic patients.]

It has been established that the age together with the number of chronic diseases cause the decrease of the reactivity of the microcirculatory bed. This study aims to evaluate the relationship between cutaneous microcirculation parameters and biological and chronological age of patients with diabetes mellitus. 11 diabetic patients (median age 57 (51; 64) years) were examined in course of this study; biological age was figured by Aging.AI3.0 calculator. Cutaneous microcirculation parameters were measured by laser Doppler flowmetry with an occlusion-heating test. Spearman's rank correlation coefficients were calculated to analyze the relationships between quantitative parameters. Significant multiple negative correlations of biological age and microvascular reactivity indices on exposure to both heat and occlusion (correlation strength from -0,618, to -0,97, p<0,05) were found. Diabetic patients have decreased microvascular reactivity that is more associated with biological age than with chronological age.

Fibroin-Gelatin Composite Stimulates the Regeneration of a Splinted Full-Thickness Skin Wound in Mice.

The effects of composite fibroin-gelatin microparticles (100-250 µ) on the rate of wound healing and regeneration under conditions of contraction prevention were studied on the model of splinted full-thickness skin wound in a mouse. Subcutaneous injection of these particles into the defect area accelerated wound healing and promoted re-epithelialization and recovery of normal structure of the epidermis. In addition, the composite microparticles promoted the formation of connective tissue of characteristic structure, replacing the derma over the entire defect, and stimulated regeneration of subcutaneous muscle (panniculus carnosus) and skin appendages (sebaceous glands and hair follicles).