Intravital direct visualization of hypoxia using a genetically encoded optical sensor
Hypoxia, which describes the insufficient supply of tissues with oxygen, may be caused as an acute process through the occlusion of a vessel during an infarction or as a chronic process through impaired blood flow caused by narrowing of the vessel lumen. Furthermore limited hypoxia has been proposed to be indispensable for development and function of certain organs. Technically it is virtually impossible to determine the oxygen pressure at the level of individual cells. Therefore, we have started to develop genetically encoded, protein-based systems that indicate hypoxia through fluorescence. For the first time this allows the analysis of hypoxia under physiological and pathological conditions by using light microscopy, even more to visualize hypoxia in living cells.