Scientists Identify a New Role for Oxygen in Wound Healing
Oxygen and Healing Wounds
Ohio State University medical researchers have demonstrated that reactive oxygen species at appropriate levels can support the healing of wounds, and specifically that wounds can generate their own low concentration of hydrogen peroxide, which has a role in healing.
A recent Ohio State study showed that at the site of injury, cells of wound tissue convert oxygen to reactive oxygen species, triggering oxidation-reduction, or redox driven mechanisms. Excess levels of reactive oxygen species, such as during chronic inflammation, may impair healing, but low levels offer healing benefits.
The observation that the redox state of the wound tissue may influence healing outcomes could lead to consideration of a novel redox-based principle for wound therapy, said Chandan Sen, lead author of a paper detailing the findings and professor and vice chair of the department of surgery at Ohio State.
The research paper is available in the online version of Molecular Therapy, the journal of the American Society of Gene Therapy.
A key characteristic of problem wounds is that they are hypoxic, or suffer from poor oxygenation, meaning too little oxygen is available to initiate the reactive oxygen-dependent healing processes.
"Proper oxygenation of a wound is a fundamental pre-requisite," said Sen, also deputy director of the Davis Heart and Lung Research Institute at Ohio State and chief editor of the international journal Antioxidants and Redox Signaling.
Under conditions of sufficient oxygenation, wound-related cells generate small amounts of reactive oxygen products, including hydrogen peroxide, which, at correct levels, acts as a chemical messenger to support healing. The hydrogen peroxide in question is not the typical household strength 3 percent solution, but a lower concentration of the compound that at a molecular level sends a message needed to trigger angiogenesis, or the formation of new blood vessels, the scientists found.
Their study provides the first direct evidence that low levels of hydrogen peroxide are enzymatically generated by the body as a wound heals in healthy tissue.
Problem wounds, however, may suffer from conditions that limit hydrogen peroxide production at the wound site. These conditions cause improper oxygenation and compromised immune function, or stem from genetic defects or chronic conditions such as diabetes that compromise the enzyme NADPH oxidase, a cellular mechanism behind the ability to kill bacteria. In these and similar cases in which the body can't be counted on to heal itself, appropriate delivery of reactive oxygen species could provide a new basis for therapeutic exploration, the scientists said.