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

Известно, что с возрастом и при ряде хронических заболеваний происходит снижение реактивности микроциркуляторного звена кровообращения. Целью данного исследования стала оценка взаимосвязи параметров кожной микроциркуляции с биологическим и хронологическим возрастом у пациентов с сахарным диабетом. В исследование были включены 11 человек с сахарным диабетом [медиана возраста 57 (51; 64) лет]; биологический возраст определяли с помощью калькулятора Aging.AI. Показатели кожной микроциркуляции оценивали с помощью метода лазерной допплеровской флоуметрии в ходе окклюзионно-теплового теста. Для анализа взаимосвязи количественных параметров рассчитывали коэффициенты ранговой корреляции Спирмена. Были выявлены значимые множественные отрицательные корреляции биологического возраста с показателями реактивности микрососудов как при тепловом, так и при окклюзионном воздействии (сила корреляций от -0,618 до -0,97, p<0,05). У лиц с сахарным диабетом снижение реактивности микрососудов в большей мере ассоциировано с биологическим возрастом, чем с хронологическим. 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.AI 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.

Correlation and spectral analysis of microcirculatory changes in symmetric areas of human head in short-term hypoxic exposure

Purpose. To study the effect of short-term hypoxic exposure on correlation between microcirculatory parameters (MCR) of symmetric areas of the human head. Materials and methods. MCR parameters of 10 healthy male volunteer were measured by laser Doppler flowmetry method. Short-term hypoxic exposure was produced according to the hypoxic test method using the ReOxy Cardio unit (S. A. Aimediq). We assessed the perfusion metrics left and right areas of interest, neurogenic, myogenic, respiratory and cardiac contributors to vascular tone and correlations between baseline parameters and after hypoxic exposure. Results. We revealed the specificity of regional circulation system rearranging induced by hypoxic load. The specificity is caused by functional asymmetry of correlations between different vascular tone contributors in symmetrical head areas. Strong correlation declining under the hypoxic loads between baseline perfusion on left/right was found. The perfusion changes of symmetrical temporal areas under the hypoxic loads correlate negatively with the baseline perfusion of both the same and the opposite side. Conclusion. Short-term hypoxic load rearranges the balance of different vascular tone contributors regulatory role in MCR of symmetric head areas to maintain the sustainable activity of the whole MRC.

Changes in micro- and central hemodynamic parameters in rats under the action of acetylsalicylic acid and its coordination compounds with metals

Introduction. The cutaneous blood circulation is a representative model both for studying the mechanisms of vascular diseases and for assessing the current state of the central hemodynamics in preclinical researches of various chemical compounds. Aim. The changes in the parameters of cutaneous microcirculation and central hemodynamics (heart rate and blood pressure) were studied in the animals under the action of acetylsalicylic acid and its coordination compounds with cations of cobalt, zinc, nickel and manganese at a dose of 20 mg/kg. Materials and methods. The research was conducted using the laser Doppler flowmetry method on the Lazma-MC device (manufactured by RPE Lazma, Russia) and the NIBP200A system (Biopac Systems, Inc., USA). Results. The study shows that animals develop bradycardia, and microcirculation and central hemodynamics change in two ways after the introduction of acetylsalicylic acid and the tested metal salicylates. These ways are hypotension-related hyperemia (acetylsalicylic acid and cobalt salicylate) and ischemia (zinc, nickel and manganese salicylates) associated with hypertension. Conclusion. The obtained data confirm the cardiotropic activity of new coordination compounds. The data also prove that the generation of the acetylsalicylic acid derivatives allows enhancing it physiological effects, as well as obtaining completely new molecules. The molecules are different from the precursor one and are necessary for the production of effective drugs.

Hypertensive patients features of the microcirculation type after new coronavirus infection of COVID-19

Introduction. The COVID-19 pandemic multiplies the incidence of long-term adverse events. Family history of heart disease predicates the necessity of study hemostasis in hypertensive patients. The purpose was to study the microcirculation in hypertensive COVID-19 survivors. Materials and methods. We selected patients treated at the hospitals of Samara from January to March 2021. COVID-19 survivors (diagnosis was confirmed by polymerase chain reaction analysis) were divided into 2 groups and analysed: the group with family history of hypertension (167 patients) and control group with no relevant past medical history (68 patients). The main microcirculation characteristics were evaluated by laser Doppler flowmetry of skin blood flow. Results. The average age of COVID-19 survivors was 52.3±14.2 years, n=86 (51.4 %) – male. The majority of patients (n=61/36.5 %) were 45 to 54 years. A fifth of the patients (n=35/20.9 %) showed no complaints about the underlying disease, the clinical manifestations of the rest were general weakness, fever, shortness of breath, cough, headaches, unstable blood pressure, inflammation of the ENT organs. By comparison the microcirculation parameters of the case patients and control group, a decreased perfusion was detected. It requires a preventive medicine to prevent from early and distant micro and macrothrombosis. Conclusion. The study of microcirculation essential features by the LDF of skin blood flow revealed a pathological type with a predominance of vasoconstrictions in patients with a history of hypertension. Taking into account the proven increase in the incidence of thrombotic events in COVID-19 survivors, the noticed changes in microcirculation require a new approach to prevent from adverse events concerning the hypercoagulation process, especially in patients with famil y history of heart disease.

Investigation of changes in the skin blood microcirculation when performing the hatha yoga breathing technique

Introduction. Yoga breathing exercises improve the ability to significantly reduce the respiratory rate. A decrease of the minute respiration volume results in compensatory reactions of the microcirculatory bed caused by changes in the gas composition. The reaction of the regulatory mechanisms of the microvascular bed can be evaluated by the optical non-invasive laser Doppler flowmetry method. The aim of the study was to assess the tissue microcirculation parameter changes in people performing yoga breathing exercises. Materials and methods. 25 volunteers performed yoga breathing exercises at a frequency of 3 times per minute, 2 times per minute, 1.5 times per minute, 1 time per minute for 5 minutes, and free breathing for 6 minutes before and after breathing exercises. Parameters aimed to defin the reaction of skin microcirculation in different body areas were simultaneously recorded in six sites by laser Doppler flowmetry using a distributed system of wearable analyzers. The parameters of tissue microcirculation recorded by the method of laser Doppler flowmetry were: the index of microcirculation (Im), nutritive blood flow (Imn), the amplitude of myogenic (Am), neurogenic (An), endothelial (Ae), respiratory (Ar) and cardiac (Ac) regulation circuits. Results. Yoga breathing exercises led to increase of microcirculation index at all breathing frequencies. Breathing at a frequency of 1.5 and 1/minute leads to a significant increase in nutritional blood flow. Low-frequency breathing exercises lead to an increase in blood pressure at the lowest breathing rates – 1.5/minute and 1/minute. The most significant changes were achieved at the lowest respiration rates (1 and 1.5/minute), that could be associated with hypoxic-hypercapnic mechanisms. Conclusion. The absence of significant changes in microcirculation parameters after low-frequency respiration during measurements in the supraorbital arteries in both groups characterizes the work of homeostatic mechanisms for maintaining brain perfusion in stressful situations for the body (low-frequency types of respiration, hypercapnia and hypoxia). When measured in the extremities, a change in the effect of the circulatory system regulatory mechanisms was observed; along with an increase in skin perfusion and the nutritional component, it can characterize the compensatory reaction of the microcirculation to respiration change.

Microcirculation disorders in patients with severe COVID-19 and development of bacterial sepsis

It is believed that microcirculation dysfunction in sepsis primarily caused by damage of the endothelium by infectious agents and pro-inflammatory cytokines. Mechanisms of impaired microcirculation in the severe course of COVID-19 and sepsis likely to be similar. However, there are few reports studied microcirculation disorders in patients with COVID-19, and their results are sometimes contradictory. Objective. To assess the microcirculation of patients with severe Covid-19 and the development of bacterial sepsis using nail bed microscopy and laser Doppler flowmetry. Materials and methods. 16 intensive care unit COVID-19 patients subsequently diagnosed with bacterial sepsis were examined. Patients underwent vital capillaroscopy and an occlusive test using laser Doppler flowmetry. The average rate of capillary blood flow, the size of the perivascular zone, the density of capillaries, the presence of intravascular aggregates, the increase in the amplitude of the maximum post-occlusive blood flow and the average value of postocclusive blood flow relative to the initial one were valuated. Additionally, the level of serum proadrenomedullin was evaluated. Studies were performed on the day of admission and in dynamics. Results. By the capillaroscopy analysis, microcirculation disorders were detected in the form of a decrease in the linear speed of capillary blood flow (<400 μm/s), an extention of the perivascular zone (>100 μm), the circulation of microaggregates; the absence of postocclusive hyperemia was determined by an occlusive test. Secondary bacterial infection led to an even greater aggravation of microcirculation disorders: an increase of the perivascular zone, the progression of intravascular aggregation resulting in microthrombosis with a decrease of the density of the capillary network (according to capillaroscopy), as well as a sharp decrease of amplitude maximal increment of blood flow of post-осclusive circulation at the time of an occlusive sample. We also revealed a trend of negative correlation between the level of serum proadrenomedullin and the maximum increase in blood flow during the occlusive test. Conclusion. The secondary bacterial infection in patients with COVID-19 leads to a significant aggravation of microcirculation disorders with the development of perfusion deficiency and interstitial edema. The increased plasma proadrenomedullin level supports the concept of the significant role of endothelial dysfunction in the pathogenesis of severe COVID-10 and bacterial sepsis.

Sex features of cutaneous microvasculature in healthy working-age people

Aim. To study sex characteristics of cutaneous microvascular structure and function in a cohort of healthy working-age people without cardiovascular diseases.Material and methods. The study included 35 healthy men (42±4 years) and 34 women (41 ±5 years). The cardiovascular system was assessed in all patients. The microcirculatory bed of the skin was investigated by the following non-invasive methods: 1) computerized video capillaroscopy; 2) laser Doppler flowmetry; 3) photoplethysmography.Results. According to computerized video capillaroscopy in men, compared with women, there was a smaller number of both functioning capillaries (78 vs 86 capillaries/mm2, respectively (p<0,05)) and their total number (100 vs 120 capillaries/mm2, respectively (p<0,001)). Against the background of a decrease in capillary density in men, there was a higher skin interstitial hydration — 113 vs 96 gm (p<0,005) in men than in women. At the level of precapillary arterioles, where humoral tone regulation prevails. Laser Doppler flowmetry revealed lower pulse amplitude in men than in women — 0,87 vs 1,02 pf, respectively (p<0,05), which indicates a lower arterial blood inflow to exchange microvessels. Against this background, the constrictor response of precapillary arterioles to a sympathetic nervous system stimulation in men is higher than in women — 45% vs 40%, respectively (p<0,05). At the level of large arterioles, where neural tone regulation prevails, photoplethysmography revealed lower augmentation index standardized at a heart rate in men (-4,6 vs 1,7%, respectively, p<0,05), which indicates lower rigidity of muscular vessels in men.Conclusion. In working-age healthy people, sex differences are noted at all cutaneous microvascular levels, which must be taken into account when planning studies.

Evaluation of Shoulder Microcirculation Abnormality Using Laser Doppler Flowmetry

Severe neck-shoulder pain induces functional limitations in both life and work. The purpose of this study was to determine the characteristics of shoulder microcirculation abnormality in workers. This study recruited 32 workers and patients, both n = 16. Questionnaires were administered, and Laser Doppler Flowmetry (LDF) was used to measure microcirculatory blood flow (MBF) at the myofascial trigger points (MTrPs) on the shoulders. The absolute-deviationMMBF represented the mean MBF (MMBF) variability among subjects. The differences in the life characteristics, shoulder pain level, and microcirculatory characteristics at MTrPs between the two groups were compared. It was found that shoulder pain level was significantly higher in the patient than in the control group (p < 0.001). Deviation of the MMBF value beyond the postulated “normal range” of 60–80 was significantly higher in the patient than in the control group (p < 0.001). The MMBF deviation was significantly correlated with shoulder pain level, pain duration, and the symptom effect (p < 0.01, n = 32). A normal range for the MMBF of 60–80 on the shoulder near MTrPs is hypothesized for the first time based on this study. Noninvasive LDF can be used to assess abnormality in the MBF on shoulder MTrPs at an early stage.

Nitric Oxide-mediated Cutaneous Microvascular Function is not Altered in Young Adults Following Mild-to-Moderate SARS CoV-2 Infection.

Vascular dysfunction has been reported in adults who have recovered from COVID-19. To date, no studies have investigated the underlying mechanisms of persistent COVID-19-associated vascular dysfunction. PURPOSE: To quantify nitric oxide (NO)-mediated vasodilation in healthy adults who have recovered from SARS-CoV-2 infection. We hypothesized that COVID-19-recovered adults would have impaired NO-mediated vasodilation compared to adults who have not had COVID-19. METHODS: We performed a cross-sectional study including: 10 (5M/5W, 24 ± 4yrs) healthy control (HC) adults who were unvaccinated for COVID-19, 11 (4M/7W, 25 ± 6yrs) healthy vaccinated (HV) adults, and 12 (5M/7W, 22 ± 3yrs) post-COVID-19 (PC, 19 ± 14wks) adults. COVID-19 symptoms severity (survey) were assessed. A standardized 39°C local heating protocol was used to assess NO-dependent vasodilation via perfusion (intradermal microdialysis) of 15 mM NG-nitro-l-arginine methyl ester during the plateau of the heating response. Red blood cell flux was measured (laser-Doppler flowmetry) and cutaneous vascular conductance (CVC = flux/mmHg) was expressed as a percentage of maximum (28mM sodium nitroprusside + 43°C). RESULTS: The local heating plateau (HC: 61 ± 20%, HV: 60 ± 19%, PC: 67 ± 19%, p=0.80) and NO-dependent vasodilation (HC: 77 ± 9%, HV: 71 ± 7%, PC: 70 ± 10%, p=0.36) were not different among groups. Neither symptom severity (25 ± 12 AU) nor time since diagnosis correlated with the NO-dependent vasodilation (r=0.46, p=0.13; r=0.41, p=0.19, respectively). CONCLUSION: Healthy adults who have had mild-to-moderate COVID-19 do not have altered NO-mediated cutaneous microvascular function.