Masahiko Tokumine

Effects of a p38 mitogen-activated protein kinase inhibitor as an additive to Euro-Collins solution on reperfusion injury in canine lung transplantation1.

Background. The activation of p38 mitogen-activated protein kinase (MAPK) plays an important role in the development of ischemia/reperfusion injury. FR167653 is a novel p38 MAPK inhibitor. This study evaluated the effects of p38 MAPK inhibition during cold ischemia on subsequent reperfusion injury using FR167653 as an additive to Euro-Collins solution in canine lung transplantation. Methods. Canine orthotopic left lung transplantation was performed after 12-hr cold storage using Euro-Collins solution, with or without FR167653. Fifteen minutes after reperfusion, the right pulmonary artery and the right stem bronchus were ligated, and the animals were observed for 4 hr after reperfusion. Left pulmonary vascular resistance (L-PVR), cardiac output (CO), arterial oxygen pressure (Pao2), and alveolar-arterial oxygen pressure difference (A-aDo2) were measured. Lung specimens were harvested for wet-to-dry lung weight ratio (WDR) measurements, histopathologic studies, and polymorphonuclear neutrophil (PMN) counts. The activities of p38 MAPK in lung grafts were evaluated. Results. The addition of FR167653 significantly (P <0.05) improved Pao2, A-aDo2, L-PVR, CO, and WDR and suppressed PMN infiltration after transplantation. FR167653 also ameliorated histologic damage to the lung graft. During cold storage, p38 MAPK was not activated in the lung graft, whereas it was markedly activated 30 min after reperfusion. FR167653 significantly (P <0.05) inhibited p38 MAPK activation 30 min after reperfusion. Conclusions. The addition of FR167653 to Euro-Collins solution improved lung graft viability associated with the inhibition of p38 MAPK activation. These results suggest that inhibiting p38 MAPK activation may attenuate ischemia/reperfusion injury in lung transplantation.

Effects of adding P38 mitogen-activated protein-kinase inhibitor to celsior solution in canine heart transplantation from non-heart-beating donors.

Background. The activation of p38 mitogen-activated protein kinase (MAPK) plays an important role in ischemia-reperfusion injury. This study evaluated the effects of p38 MAPK inhibition using FR167653, a novel p38 MAPK inhibitor, as an additive to Celsior solution in canine heart transplantation from non–heart-beating donors (NHBDs). Methods. Donor hearts were left in situ for 20 minutes after cardiac arrest, which was induced by rapid exsanguination. Twelve donor-recipient pairs of mongrel dogs were divided into two groups: the control and FR167653 (FR) groups (n=6 each). In both groups, the grafts were subjected to coronary flushing and immersed in Celsior solution for 4 hours with or without FR167653. Orthotopic heart transplantation was then performed. Cardiac output (CO), left ventricular pressure (LVP), and end-systolic maximal elastance (Emax) were measured 2 hours after weaning from cardiopulmonary bypass (CPB), and the hearts were then harvested for histopathologic study. The activation of p38 MAPK was evaluated in another 20 mongrel dogs. Results. In the FR group, CO, LVP recovery rate, and Emax were significantly (P <0.05) higher 2 hours after weaning from CPB, histopathologic damage was attenuated, and the activation of p38 MAPK was significantly (P <0.05) inhibited 10 minutes after reperfusion compared with the control group. Conclusions. The addition of FR167653 to Celsior solution improved heart-graft viability, probably by way of the inhibition of p38 MAPK activation, which may attenuate ischemia-reperfusion injury in heart transplantation from NHBDs.

Effects of a bradykinin B2 receptor antagonist on ischemia–reperfusion injury in a canine lung transplantation model

BACKGROUND This study investigated the effects of a bradykinin B(2) receptor antagonist, FR173657 (FR), on ischemia-reperfusion (I/R) injury in a canine lung transplantation model. METHODS Eighteen pairs of weight-matched dogs were randomly divided into 3 groups. Six pairs were assigned to the FR(D+R) group, in which FR (100 nmol/kg/h) was administered to the transplant donor continuously beginning 30 minutes before ischemia until the onset of ischemia, and FR was administered to the transplant recipient beginning 30 minutes before reperfusion and continuing for 2 hours after reperfusion. Another 6 pairs of dogs were assigned to the FR(R) group, in which FR was administered only to the recipient in the same manner as in the FR(D+R) group. The other pairs were assigned to the control group, in which vehicle alone was administered. Orthotopic left lung transplantation was performed after 12-hour cold storage in Euro-Collins solution. Fifteen minutes after reperfusion, the right pulmonary artery and the right stem bronchus were ligated. The animals were measured for 4 hours after reperfusion for left pulmonary vascular resistance (L-PVR), cardiac output (CO), arterial oxygen pressure (PaO(2)) and alveolar-arterial oxygen pressure difference (A-aD(O(2))). Lung specimens were harvested for measurement of the wet-to-dry lung weight ratio (WDR), histopathologic studies and polymorphonuclear neutrophil (PMN) count. RESULTS Compared with the control group, PaO(2), A-aDO(2), L-PVR and CO were all significantly (p < 0.05) improved and WDR significantly (p < 0.05) lower in both the FR(D+R) and FR(R) groups. Moreover, in the FR-treated groups, histologic tissue edema was mild, and PMN infiltration was significantly (p < 0.05) reduced. CONCLUSIONS The bradykinin B(2) receptor antagonist, FR173657, ameliorates I/R injury in lung grafts, indicating that protection of lung grafts can be achieved by the administration of FR solely to the transplant recipient.

The optimal pressure for initial flush with UW solution in heart procurement

OBJECTIVE University of Wisconsin (UW) solution is widely used in organ preservation. Some investigators have reported that high pressure during initial flush with UW solution may induce vasoconstriction and endothelial damage, because of its high potassium content and high viscosity. However, using lower pressure during the initial flush may lead to irregular distribution of the solution and incomplete flushing of blood components from coronary vascular beds. This experimental study evaluated the effects of a range of initial flush pressures during heart procurement, followed by orthotopic transplantation of the graft after 12 hours of preservation. MATERIALS AND METHODS Twelve pairs of adult mongrel dogs, weighing 9 to 14 kg, formed the recipient-donor combinations. After determining hemodynamic status by measuring cardiac output, left ventricular pressure (LVP), and maximum positive and negative change in LVP (+/-LVdP/dt), donor hearts were excised. Coronary vascular beds were flushed with 4 degrees C UW solution at a pressure of 60 mm Hg in the low-pressure group (n = 6) and at 120 mm Hg in the high-pressure group (n = 6). After 12 hours of cold preservation, orthotopic transplantation was performed using cardiopulmonary bypass (CPB). The hemodynamics of the transplanted graft were assessed by comparing recovery rates (%) from donor hearts 2 hours after weaning from CPB. Endothelin-1 (ET-1) levels were measured in the blood obtained from the coronary sinus 30 minutes after reperfusion. The transplanted grafts were then harvested for histologic study and measurement of adenosine triphosphate (ATP) content. RESULTS Cardiac output, LVP, LVdP/dt and myocardial tissue ATP content were significantly better (p < 0.05) in the high-pressure group than in the low-pressure group. We found no significant differences in ET-1 levels between the groups. Transmission electron microscopic findings revealed that degeneration of the mitochondria was less extensive in the high-pressure group than in the low-pressure group. We observed no obvious ultrastructural damage to the endothelial cells in either group. CONCLUSION When using UW solution in heart procurement, high pressure is better to completely wash out the blood components and distribute the solution.

Effects of a bradykinin B2 receptor antagonist, FR173657, on pulmonary ischemia–reperfusion injury in dogs

BACKGROUND This study investigated the effects of a bradykinin B(2) receptor antagonist, FR173657 (FR), on pulmonary ischemia-reperfusion (I/R) injury. METHODS Twenty-four mongrel dogs were divided into four groups (n = 6 each). In Groups I, II and III, FR doses of 33, 100 and 300 nmol/kg per hour, respectively, were administered continuously beginning 30 minutes before ischemia and continuing for 2 hours after reperfusion. In Group IV, vehicle alone was administered. Warm ischemia was induced for 3 hours by clamping the left pulmonary artery and veins. Simultaneously, the left stem bronchus was bisected and then anastomosed before reperfusion. Fifteen minutes after reperfusion, the right pulmonary artery and bronchus were ligated. Left pulmonary vascular resistance (L-PVR), cardiac output (CO), arterial oxygen pressure (PaO(2)) and the alveolar - arterial oxygen pressure difference (A-aDO2) were measured for 4 hours after reperfusion. Lung tissue was harvested for wet-to-dry weight ratio (WDR) measurements, histopathologic studies and polymorphonuclear neutrophil (PMN) counts. Serum thromboxane (TX) B(2), 6-keto-prostaglandin (PG) F(1alpha) and leukotriene (LT) B(4) levels were also measured. RESULTS PaO(2), A-aDO2, L-PVR and CO were significantly (p < 0.05) improved and WDR was significantly (p < 0.05) lower in Groups II and III than in Group IV. Histologic tissue edema was mild, and PMN infiltration was significantly (p < 0.05) reduced in Groups I, II and III compared with Group IV. TXB(2) levels were significantly (p < 0.05) lower in Group II than in Group IV, whereas 6-keto-PGF(1alpha) levels were not significantly different. LTB(4) levels were significantly (p < 0.05) lower in Groups II and III than in Group IV. CONCLUSIONS FR appears to have a protective effect on pulmonary I/R injury stemming from the inhibition of eicosanoid release.

The comparison of mitogen-activated protein kinases that become activated within the left ventricular and right atrial tissues following heart transplantation in canine model.

The activation of p38 mitogen-activated protein kinase (MAPK) plays an important role in ischemia/reperfusion injury. Some reports have documented MAPKs activation of the myocardium in human models, using right atrial (RA) tissue for samples. This study compared the activation of MAPKs in left ventricle (LV) and RA tissues in canine heart transplantation. Four dogs were used as baseline data at two points, before and 20 min after warm ischemia (baseline model), and eight dogs (four pairs of donor and recipient) were used at other points: 4 h after cold ischemia, and at 10, 60, and 180 min after reperfusion (transplantation model). In the transplantation model, donor hearts were left in situ for 20 min after cardiac arrest, and were immersed in Celsior solution for 4 h after coronary flushing. Orthotopic heart transplantation was then performed. Two groups were created: the LV and RA groups (n = 4 in each group). Heart tissue was harvested from the left ventricular wall in the LV group and from the right atrial appendage in the RA group. The activation of MAPKs, including p38 MAPK, c-Jun N-terminal protein kinase (JNK), and extracellular signal-regulated protein kinase (ERK), was evaluated at each point. The activation patterns of p38 MAPK and ERK were similar in the RA and LV groups, but JNK activation was different in the two groups, after ischemia and reperfusion. Thus, RA tissue may be deliberately used as a substitute for LV tissue when investigating the activation of MAPKs in a human model.

Effects of P38 mitogen-activated protein kinase inhibitor as an additive to celsior solution on canine heart transplantation from non-heart-beating donors

Background: The activation of p38 mitogen-activated protein kinase (MAPK) plays an important role on ischemia/reperfusion injury. FR167653 is a novel p38 MAPK inhibitor. This study evaluated the effects of p38 MAPK inhibition using FR167653 as an additive to the Celsior solution in canine heart transplantation from non-heart-beating donors (NHBDs). Methods: Donor hearts were left in situ for 20 min after cardiac arrest induced by rapid exsanguination. Twelve donor-recipient pairs of mongrel dogs were divided into two groups, the control and FR group (n = 6 each). Both group animals underwent coronary flushing and were immersed into the Celsior solution with or without FR167653 for 4 hr. Orthotopic heart transplantation was then performed. Cardiac output (CO), left ventricular pressure (LVP) and end-systolic maximal elastance (Emax) were measured at 1 and 2 hr after weaning from cardiopulmonary bypass (CPB), and then grafts were harvested for histopathological study. The activation of MAPKs including p38 MAPK, c-Jun N-terminal protein kinase (JNK) and extracellular signal-regulated protein kinase (ERK) were evaluated by the use of other 12 mongrel dogs during the heart transplantation procedure. Results: CO and LVP recovery rates and Emax were significantly (p < 0.05) higher in the FR group than in the control group 2 hr after weaning from CPB. Histopathological damage was more severe in the control group. The p38 MAPK, JNK and ERK were significantly (p < 0.05) activated in the control group after reperfusion. The p38 MAPK activation was significantly (p < 0.05) inhibited in the FR group than in the control group 10 min after reperfusion. Conclusions: The addition of FR167653 to the Celsior solution improved graft viability which might be due to the inhibition of p38 MAPK activation after transplantation, and may attenuate ischemia/reperfusion injury in heart transplantation from NHBDs.