Potential of hyperbaric oxygen in urological diseases.

Hyperbaric oxygen therapy is a promising medical technology that delivers oxygen to targeted tissues at high pressure to increase the amount of dissolved oxygen in the blood. Over the past three decades, hyperbaric oxygen has been used in a variety of conditions, including radiation-induced tissue injuries, non-healing states with ischemia and malignant neoplasms. In the field of urology, hyperbaric oxygen has also been applied to some pathological conditions (e.g. radiation-induced hemorrhagic cystitis, Fournier gangrene, interstitial cystitis, male infertility, acute kidney injury and urological cancers). In normal and injured tissues, hyperoxia from hyperbaric oxygen therapy contributes to anti-inflammation, angiogenesis through endothelial proliferation, enhanced fibroblastic activity, increased lymphocyte and macrophage activity, and bactericidal effects with the aim of wound repair. In cancerous tissues, the enhanced supply of oxygen into the hypoxic cancer cells can exert inhibitory effects on factors that contribute to their aggressiveness (e.g. cell survival, escape from apoptosis, epithelial-to-mesenchymal transition and tumor immunotolerance), and sensitize the tumor to radiation therapy and chemotherapy. However, further research, including multicenter clinical studies, is essential for determining the role of hyperbaric oxygen therapy in refractory urological diseases that are resistant to conventional therapies.