Features of blood microcirculation across different age groups in relation to urban ecosystem conditions

BACKGROUND: Understanding adverse effects of environmental factors, including those associated with urbanization and high population density, are important for development of public health protection measures. The hemodynamics of the microcirculatory system plays a significant role in maintaining tissue homeostasis, with morphofunctional characteristics often present in most cases of diseases. However, there remains a lack of comprehensive research on the aging process and the effects of residing in different urban settings on microcirculation dynamics. AIM: To study the changes in the microcirculatory system across different age groups, depending on the state of urban ecosystems, including a megalopolis and a small tourist city without significant industrial activity. MATERIAL AND METHODS: The study involved volunteers from the industrial megalopolis of Nizhny Novgorod and the city of Semenov, a small tourist town without significant industrial activity. Volunteers from different areas, varying in terms of human activity and environmental conditions, were divided into three age groups: group 1: 18–44 years old, group 2: 45–59 years old, and group 3: 60–74 years old. Microcirculation was measured by laser Doppler flowmetry (LDF) using a laser capillary blood flow analyzer "LAZMA ST" (NPP LAZMA LLC, Russia). The amplitude-frequency characteristics were evaluated with a wavelet analysis of blood flow oscillations. RESULTS: A comparison of the amplitude-frequency characteristics (frequency response) of microcirculation between the 1st group of a megalopolis and a small tourist city with minimal industrial activity did not reveal any significant differences. However, upon further analysis of the amplitude-frequency spectrum of groups 2 and 3, changes in the reactivity of microcirculatory structures were observed, depending on age and urban environment. Inter-group differences based on urban ecosystems were identified through variations in endothelial rhythm amplitudes (Ae), neurogenic rhythm (An), myogenic oscillations (Am), and heart rate amplitude (Ah). The megalopolis group exhibited a decrease in An, Am, and Ah, along with an increase in Ae in groups 2 and 3. In contrast, the small city population showed a decrease in Ae, An, and As in group 2, followed by an increase in Ae, An, Am in group 3, and a further decrease in As compared to age groups 1 and 2. Furthermore, the indicator reflecting the power of blood flow into the microcirculatory bed decreased in the 3rd age group of the megalopolis. CONCLUSION: The analysis of microcirculation using the LDF method allows to identify the involvement of various mechanisms regulating microcirculation, depending on the condition of the agro-ecosystem and the presence of risk factors that reduce adaptive capacity with age and living in a megalopolis. The findings from this study can be used to develop measures to prevent tissue perfusion insufficiency in different urban environments.