Stem cell therapy for pulmonary arterial hypertension: An update.

Pulmonary arterial hypertension (PAH) remains a deadly disease, and there currently is no cure for this life-threating medical problem. The average lifespan is about 5 to 7 years after diagnosis of PAH. Therefore, a conceptual breakthrough to develop new therapeutic strategies for PAH is urgently needed. Growing evidence shows that stem cells are emerging as a novel effective treatment, but the understanding of its underlying mechanisms is still limited. This review highlights the mechanisms through which stem cells successfully reverse pulmonary vascular endothelial dysfunction, pulmonary artery smooth muscle cell over-proliferation, and mitochondrial dysfunction in PAH patients and common rodent models used in PAH research. They can modulate common underlying pathways involved in PAH, including the nitric oxide synthase, mitochondrial regulators, microRNAs and STAT3-BMPR signaling. Genetic modifications further enhance the therapeutic effects of stem cells on PAH. Clinical trials showed promising therapeutic potential of mesenchymal stem cells and endothelial progenitor cells for PAH. Potential limitations and challenges are also discussed. The current findings support the need for further investigation and validation of stem cell therapy for PAH.