Vol 31, No 5 (2024)

BACKGROUND: The microbiota of the indigenous population of the North may play a pivotal role in the development of the polar (northern) type of metabolism supporting increased energy demands and maintaining body homeostasis in extreme cold climates. However, this area remains relatively understudied. Sequencing of bacterial 16S rRNA allows for establishing the full taxonomic composition of microbial communities, thereby facilitating novel insights into the interplay between microbiota, environmental conditions, and the formation of health in different populations.

AIM: The aim of this review is to evaluate the factors and principles of microbiota development in extreme climatic conditions and its potential impact on health in the indigenous peoples of the North.

MATERIALS AND METHODS: A systematic review was conducted based on the 2020 PRISMA guidelines. Original studies were searched for across the PubMed, eLibrary, and Google Scholar databases using Russian keywords “микробиота кишечника” (“intestinal microbiota”), “Север” (“North”), and English “gut microbiome,” “16S rRNA,” and “Arctic.”

RESULTS: Having filtered the results of the primary selection of articles in accordance with the search criteria, five publications were identified that presented the results of intestinal microbiota 16S rRNA studies in Canadian Inuit, Alaska Natives, and Yakuts of the Sakha Republic (Yakutia). The intestinal microbiota of native residents of the North differs is characterized by inter- and intra-population variability in the diversity and taxonomic composition. Despite similar climatic conditions and dietary patterns, microbiota composition of different Northern populations reflects differences in traditional activities, dietary habits, and surrounding animals.

CONCLUSION: Results of available studies are insufficient to form a comprehensive understanding of the northern microbiome and its role in maintaining the health of the indigenous peoples of the North. Nevertheless, the composition of the intestinal microbiota of the northern populations is shown to be diverse and favorable for the metabolic health; further studies are required to identify the mechanisms of the metabolic health formation in cold climate conditions.

BACKGROUND: Obesity is a chronic disease that represents a significant risk factor of type 2 diabetes mellitus and cardiovascular diseases, as well as a primary contributor to disability. This condition affects individuals of all age groups, including children, which represents a particularly concerning trend. The incidence of obesity over multiple years has not been sufficiently studied in Russia. It is therefore pertinent to analyze the incidence of obesity over time in different age groups in order to identify the principal determining factors.

AIM: To evaluate the main dynamic and age-related characteristics of obesity morbidity in the Arkhangelsk Region.

MATERIALS AND METHODS: We conducted a retrospective, analytical, non-randomized study. The 1991–2022 changes in the primary obesity morbidity in the Arkhangelsk Region population was analyzed. The contribution of the incidence in different age groups to the total change in the primary morbidity and degree of chronification in the population was investigated. The extent of underreporting of obesity morbidity during the period of the pandemic was estimated. The study employed a variety of analytical techniques, including the use of standardized indicators, time series analysis, and index methods.

RESULTS: Our findings revealed a consistent increase in the primary morbidity of obesity over the 1991–2006 period, followed by a subsequent decline. The overall primary morbidity demonstrated a 506.4% increase. The changes in the primary obesity morbidity across the population are most closely aligned with those observed in the 0- to 14-year-old age group. The substantial fluctuations in the primary morbidity among the overall population are associated with those observed in the older age groups. Obesity is a chronic disease, and the proportion of individuals who are chronically obese is increasing. It is estimated that the primary morbidity of obesity was underreported by 16.8% during the period of the pandemic.

CONCLUSION: The analysis of the dynamic characteristics of the obesity morbidity allows for assuming its significant dependence on administrative factors, most notably on changes in diagnostic criteria. It is evident that there is an unmet need in the programs designed to report, treat, and prevent obesity, particularly in children, with the aim of reducing the cardiometabolic population burden and other risks. This is particularly pertinent in the context of the need to develop the Arctic zone of the Russian Federation and to protect health in the region.

BACKGROUND: One of the specific and underexplored issues in human ecological physiology and medicine in the North is cardiac function during hypoxemia in the cold season. This formed the basis of the current study.

AIM: To examine the changes in the bioelectrical activity of the heart and the integral typology of responses to acute hypoxia before and after interval normobaric hypoxic training in healthy individuals during the winter season in Northern Russia.

MATERIALS AND METHODS: The study included 29 men (mean age 20.2±0.31 years) exposed to acute hypoxia (12.3% O₂) for 20 minutes. Blood oxygenation (SpO₂%) and three amplitude and temporal ECG parameters were recorded at baseline and on Days 1, 7, and 16 following intermittent normobaric hypoxic training. Integral values of the heart’s chronotropic and inotropic responses were determined.

RESULTS: At baseline, during acute hypoxia, P₁II (р=0,005) and P-Q (р=0,006) increased, while RII, T₁II, R-R, and Q-T (р <0,001) decreased. Following intermittent normobaric hypoxic training, the deviation in T₁II during acute hypoxia reduced from Day 1 (p=0.030) to Day 16 (p <0.001), and P₁II decreased by Day 16 (p=0.020). Deviations in T₁II and Q-T correlated consistently with those in SpO₂%. During episodes of acute hypoxia, mesoreactive responses were observed in 42.5–47.1% of cases, hyperreactive responses in 24.1–29.9%, and hyporeactive responses in 27.6–28.7%. Integral values of polar chronotropic and inotropic reactions to acute hypoxia increased significantly from Day 7 following intermittent normobaric hypoxic training compared to baseline.

CONCLUSION: Intermittent hypoxic training reduces alterations in the bioelectrical activity of the right atrium during acute hypoxia, and mitigates the suppression of ventricular myocardial activity during the rapid terminal repolarization phase. Ventricular systole becomes increasingly dependent on developing hypoxemia. While the quantitative proportions of polar chronotropic and inotropic responses remain unchanged, their integral mean values increase significantly.