Hypoxic microenvironment and pulmonary hypertension.

Pulmonary hypertension (PH) is a serious pulmonary vascular disease characterized by a progressive increase in pulmonary vascular resistance and abnormally high pulmonary arterial pressure. The hypoxic microenvironment plays an important role in its development. Studies have indicated that early exposure of pulmonary vasculature to hypoxia in the hypoxic microenvironment triggers an adaptive response in the organisms and has a homeostatic regulatory effect. However, under prolonged hypoxic stimulation, pulmonary artery smooth muscle cells (PASMCs) and pulmonary artery endothelial cells (PAECs) can be induced to abnormally proliferate and migrate through endothelial cell dysfunction and endothelial-mesenchymal transition. This leads to irreversible pulmonary vascular remodeling, which ultimately results in PH formation. Core components of the hypoxic microenvironment include hypoxia-inducible factors (HIFs) through a complex regulatory network, metabolic reprogramming in the microenvironment (glucose metabolism, lipid metabolism, and amino acid metabolism), an overabundance of reactive oxygen species and redox imbalance, reprogramming of the immuno-inflammatory microenvironment, regulation of cell death patterns (apoptosis resistance, iron death, and autophagy imbalance), mechanical stress and cytoskeletal dynamics, non-coding RNA regulatory networks (miRNA, IncRNA, and circRNA), microbial-host interactions (gut flora metabolites), epigenetic regulation (DNA methylation, histone modification, and RNA modification) and Transient Receptor Potential (TRP) Channels and Calcium Signaling Regulation. These processes are interconnected in the organisms to induce or promote aberrant proliferation and migration of PASMCs and PAECs, which are the pathogenic mechanisms resulting in PH.Current clinical treatments for PH include endothelin receptor antagonists, drugs targeting cyclic guanosine monophosphate production, phosphodiesterase-5 inhibitors, and prostacyclin analogs. However, novel targeted drugs against HIF-1ɑ remain under development. Oxygen therapy and mechanical ventilation, gene therapy, and molecularly targeted interventions (modulation of the RhoA/ROCK pathway or non-coding RNAs) can improve hypoxemia. Future studies must integrate multi-omics data, incorporate artificial intelligence to accelerate drug development, and focus on gender and individualization to achieve precision therapy. In conclusion, an in-depth analysis of the mechanism of the hypoxic microenvironment in PH will provide the fundamental basis for developing more effective therapeutic strategies.