Pancreas prostanoid production in ischemia and reperfusion

Impairment of microcirculation in the early reperfusion period predicts the degree of graft pancreatitis in clinical pancreas transplantation

BACKGROUND

Graft pancreatitis is thought to be induced by ischemia/reperfusion. Animal experiments have suggested that an impaired microcirculation is crucial in this process. We have therefore studied the relevance of microcirculation in clinical pancreas transplantation.

METHODS

In 17 patients undergoing pancreas transplantation, tissue pO2 was monitored continuously by an electrode implanted into the pancreatic tail. A catheter was inserted in the distal part of the splenic vein of the pancreas graft. After reperfusion blood samples were taken from this catheter and blood flow was measured by the venous outflow method. The degree of graft pancreatitis was assessed by peak-C-reactive protein (CRP) defined as highest CRP within 3 days after transplantation.

RESULTS

Tissue pO2 increased within 5 min after reperfusion. Thereafter, in most patients a transient decrease was noted, indicating impairment of nutritive perfusion. During this period there was an increasing negative correlation between peak-CRP and tissue pO2 which was highly significant at 60 min after reperfusion (r=-0.70, P<0.002). Also donor age correlated significantly with peak-CRP (r=0.64, P<0.005) and to a somewhat lesser extend with tissue pO2 60 min after reperfusion (r= -0.55, P<0.03).

CONCLUSION

These data show that the degree of organ damage in clinical pancreas transplantation is directly related to an impairment of microcirculation in the early reperfusion period. These data also support the idea that grafts from older donors have a higher probability to develop graft pancreatitis and that this might be due to an increased incidence of microcirculatory disturbances in these organs.

Key metabolite kinetics in human skeletal muscle during ischaemia and reperfusion: measurement by microdialysis

The tissue kinetics of key metabolites of ischaemic and postischaemic tissue damage were studied in the intercellular space of human skeletal muscle by microdialysis. In vivo microdialysis calibration experiments (n = 5) yielded the basal intercellular concentration of glucose in human skeletal muscle (3.6 +/- 0.6 mM; mean +/- SD). The corresponding mean plasma glucose concentration was 4.3 +/- 0.2 mM which was significantly higher. The time vs. concentration profiles of intercellular glucose (n = 7), lactate (n = 5), TxB2 (n = 6) and urea (n = 8) were characterized during a 20 min period of leg constriction. TxB2 increased exclusively during reperfusion in comparison to baseline (n = 6). Administration of 500 mg acetylsalicylic acid, 5-10 min after onset of ischaemia blunted TxB2-response to reperfusion (n = 4). It is concluded that intercellular muscle glucose concentration is less than that in plasma. Glucose uptake in skeletal muscle is rapid even under ischaemic conditions. Synthesis and release of TxB2 is not evident during ischaemia. TxB2 mediated reperfusion injury might be reduced by acetylsalicylic acid, even if administered after onset of ischaemia.