Simulated hypergravity upregulates mechanosensitive channels like TRPM7, inducing hypersensitivity, whereas microgravity downregulates these channels, causing cellular hyposensitivity and atrophy.
Cardiac pathology in micro- and hypergravity arises from the synergy of systemic hemodynamic shifts and profound reprogramming of cardiomyocyte mechanosensitivity.
Abstract The impact of micro- and hypergravity on the cardiovascular system represents a multi-level pathological process that begins with organ-level disorders and has a profound cellular and molecular basis. Despite more than sixty years of human spaceflight and increasing gravitational loads in modern aviation, a key link—the role of mechano-electrical feedback (MEF) and mechanosensitive channels in cardiomyocytes—remains insufficiently studied, which defines the scientific and practical significance of this review. We aimed to analyze and summarize current data on the effects of simulated micro- and hypergravity on the molecular and physiological mechanisms of cardiomyocyte function, focusing on MEF disruption in the heart as a central pathogenetic link. The objectives of this review are: (1) to compare the systemic hemodynamic effects of hypergravity (compensatory tachycardia, elevated blood pressure, myocardial hypertrophy, increased risk of arrhythmias) and microgravity (cephalad fluid shift, hypovolemia, myocardial atrophy, orthostatic intolerance upon return to Earth); (2) to characterize at the molecular and cellular level the opposing regulation of cardiomyocyte mechanosensitivity: hypergravity induces a hypersensitivity phenotype by upregulating the expression of mechanosensitive channels (e.g., TRPM7) and enhancing mechano-induced ionic currents, whereas microgravity downregulates the expression of the same channels, leading to cellular hyposensitivity and atrophy; (3) to demonstrate that cardiac pathology in micro- and hypergravity arises from the synergy of systemic hemodynamic shifts and profound reprogramming of cardiomyocyte mechanosensitivity. The understanding of this hierarchical relationship, from clinical manifestations to molecular mechanisms, is a prerequisite for developing targeted strategies to protect the cardiovascular system during spaceflight and under gravitational overloads experienced by pilots, especially combat pilots.
Bilichenko et al. (Mon,) conducted a review in Cardiovascular effects of micro- and hypergravity. Simulated micro- and hypergravity was evaluated. Simulated hypergravity upregulates mechanosensitive channels like TRPM7, inducing hypersensitivity, whereas microgravity downregulates these channels, causing cellular hyposensitivity and atrophy.