Low or blocked oxidation is normally followed by fermentation of sugar in cells, which then leads to the primary condition upon which cancer, infectious and inflammatory processes feed. Viruses are “anaerobic” creatures, which thrive in the absence of oxygen. Yeast, mold and fungus love anaerobic environments.
Most strains of harmful bacteria (and cancer cells) are anaerobic and are not comfortable in the presence of higher oxygen levels. Doctors find cancer cells easier to kill when oxygen levels are higher. It is the most hypoxic cancer cells, those lowest in oxygen with the highest output of lactic acid that are the hardest to kill even with the harshest forms of chemotherapy.
Improved tissue oxygenation combined with antimicrobials has achieved greater efficacy in pathogen clearance (Knighton et al., 1986). During infection and disease, O2 demand can increase because of various factors including increased metabolism of infiltrated immune cells and microbial proliferation, resulting in a hypoxic environment (Lewis et al., 1999). Hypoxia has a pleiotropic role in tissue inflammation and infection and may exacerbate or attenuate disease.
Areas of inadequate O2 tension in the lung of cystic fibrosis patients support colonization of Pseudomonasbacteria to establish infection and effectively block host immune responses (Callaghan and McClean, 2012 ).
Eukaryotic organisms, including Leishmania parasites, express a heme containing globin protein that functions as a natural O2 sensor to detect hypoxia and adapt accordingly to prevent cell death ( Sen Santara et al., 2013 ). These and other protozoan, bacterial, and viral infections are modulated by hypoxia, either directly or through the activation of other antimicrobial responses such as defensins.