Distinct expression of heat shock and acute phase genes during regional hepatic ischemia-reperfusion

The hepatic response to injury is orchestrated by the expression of different gene groups (i.e., heat shock and acute phase). In the present study, the expression of heat shock. and acute phase genes was analyzed in the context of a localized injury, regional hepatic ischemia-reperfusion. Left and median liver lobes were subjected to 1 h of ischemia, whereas blood flow was maintained to the remainder of the organ. After the period of ischemia, the organ was reperfused, and samples of the ischemic and nonischemic liver were obtained at different time points during reperfusion. Expression of the heat shock gene, HSP 72, was detected only in the ischemic Liver, whereas expression of the acute phase gene, beta-fibrinogen, and the interleukin-6-inducible gene, metallothionein, was maximally induced in the nonischemic liver and attenuated in the ischemic Liver. To determine how the heat shock and acute phase responses were reprioritized during stress, expression of beta-fibronogen and HSP 72 was induced simultaneously in the same animal by administration of endotoxin and total body hyperthermia, respectively. Administration of endotoxin did not impede the expression of HSP 72; however, heat shock attenuated, but did not eliminate, the endotoxin-induced expression of beta-fibronogen. These observations suggest that the heat shock and acute phase responses are not mutually exclusive.