Are local cytokine concentrations and oxygen pressure related to maturation of the collateral circulation in humans?
Intravascular ischemia during brief balloon coronary occlusion is absent in human coronary collateral arteries. The oxygen gradient found over the collateral circulation is increased in patients with a less matured collateral circulation and relates to local levels of several known pro-arteriogenic cytokines. In case of a more developed collateral circulation, relatively low levels of cytokines are present, suggesting that growth factor therapy might be beneficial at this stage.
Although useful, measurement of CSF concentrations may be an underestimation of the penetration of antiretrovirals into the brain. Limitations associated with obtaining tissue biopsies and paired plasma and CSF samples from patients make PBPK an attractive tool for probing drug distribution.