Seikon Kin

Heart preservation in HTK solution: role of coronary vasculature in recovery of cardiac function

BACKGROUND Poor myocardial tolerance to prolonged cold ischemia remains a major concern in heart transplantation. In this study, we estimated superiority of Histidine-Tryptophan-Ketoglutarate (HTK) over University of Wisconsin (UW) as a cardiac preservation solution. METHODS Isolated rat hearts were mounted on a Langendorff apparatus to estimate the baseline cardiac function. The hearts were arrested and stored at 4 degrees C in UW and HTK solution for 8 hours, and then reperfused. The aortic flow, coronary flow, cardiac output, rate pressure product, and left ventricular dp/dt in the HTK group recovered significantly more than the UW group. The values of myocardial total adenine nucleotides and the adenosine triphosphate to adenosine diphosphate ratio were higher in the HTK than in the UW group. We also examined coronary vascular responsiveness using left coronary arteries dissected from the rat hearts before flushing, before storage, after storage, and after reperfusion. RESULTS The maximal relaxation response to acetylcholine was significantly higher in the HTK than in the UW group after reperfusion, although there were no significant differences at each stage before reperfusion. In addition, the endothelium-independent relaxation response to sodium nitroprusside in the HTK group was also well preserved after reperfusion. CONCLUSIONS These results indicate that HTK is superior to UW solution for cardiac preservation. HTK protects coronary vasculature during preservation, which together with reperfusion might lead to improved functional cardiac recovery following preservation.

Effect of aging on B-cell function and replication in rat pancreas after 90% pancreatectomy.

We studied the effect of aging on B-cell function and replication in depancreatized rats. Male Wistar rats, at the ages of 1, 5, and 15 months, underwent 90% pancreatectomy (Px) or a sham operation, and islet function and regeneration were examined 3 weeks later. Plasma glucose levels in 1-month-old rats reached a peak 2 weeks after Px and then declined, while those in 5- and 15-month- old rats reached significant levels as early as the day after Px or 2 days after surgery and continued to increase over the following 3 weeks. Consequently, in contrast to young Px rats, weight loss due to severe diabetes was observed in 5- and 15-month-old Px rats. Plasma glucose responses to intravenous glucose loading (0.5 g/kg body weight) were much greater in older Px rats than in younger rats. There was a marginal insulin response to glucose in 1-month-old Px rats, whereas no insulin response to glucose was observed in older Px animals. The insulin content of the residual pancreas was increased threefold in 1-month-old Px rats, but there was no increase in 5- and 15-month-old Px rats. These data demonstrate that the effect of reducing islet mass is much greater in aged rats than in young rats and that the replicatory capacity of B cells tends to diminish after adulthood has been reached.

The role of a hydroxyl radical scavenger (nicaraven) in recovery of cardiac function following preservation and reperfusion

We investigated the efficacy in reducing myocardial preservation and reperfusion (P/R) injury of direct hydroxyl radical scavenging by nicaraven as compared with scavenging of both superoxide radicals and hydrogen peroxides by superoxide dismutase (SOD) and catalase (CAT), respectively. Isolated rat hearts were mounted on a Langendorff (L) apparatus to estimate the baseline aortic flow (AF), coronary flow (CF), cardiac output (CO), systolic pressure (SP), aortic mean pressure (MP), rate pressure product, and LV dp/dt. They were divided into 3 groups: group 1, 12 hr storage in HTK solution; group 2, 12 hr storage in HTK solution containing 2.5x10(5) U/L SOD and 2x10(5) U/L mg/L CAT; and Group 3, 12 hr storage in HTK solution containing 10(-3) M nicaraven. SOD, CAT, and nicaraven were administered intraperitoneally before harvesting. Hearts were stored in each preservation solution at 4, and then reperfused. Postpreservative function and concentrations of leaked enzymes were measured. The hearts were switched back to the L-mode and paced at 330 beats/min. CF following perfusion with Krebs-Henseleit bicarbonate buffer (KHB) solution containing 10(-6) M 5-hydroxytryptamine (5-HT) or 10(-5) M nitroglycerin (NTG) then evaluated. The myocardial water content also was measured. The recovery of CF, CO, SP, MP, and LV dp/dt was significantly greater in group 3 than in group 1. The recovery of CF was superior to that in group 2 (P<0.05). There were no significant differences in the recovery of cardiac function between groups 1 and 2. 5-HT caused a decrease in CF in each group, however, CF in group 3 was higher than that in group 1 (P<0.05). NTG caused no significant differences among the groups. There were no significant differences in leaked enzymes and myocardial water content among the three groups. These results suggest that nicaraven protects against myocardial P/R injury through its hydroxyl radical scavenging activity, and that therapy with oxygen-free radical scavengers should be directed toward inactivation of hydroxyl radicals rather than superoxide radicals and/or hydrogen peroxides.

Cardioprotective effect of nicorandil in histidine-tryptophan-ketoglurate solution during the cold storage of isolated hearts.

We compared the efficacy of using histidine-tryptophan-ketoglurate (HTK) solution with that of University of Wisconsin (UW) solution for heart preservation in an isolated rat heart preparation. Nicorandil (NCR) exerts its action as an ATP-sensitive potassium channel opener at low extracellular potassium concentrations, and HTK solution has a low potassium concentration. Therefore, we also investigated the efficacy of using HTK solution with NCR following 12-hr preservation. Hearts isolated from male Wistar rats were mounted on a Langendorff apparatus to estimate baseline aortic flow (AF), coronary flow (CF), cardiac out-put (CO), heart rate (HR), systolic pressure (SP), aortic mean pressure, and the rate-pressure product (RPP). The hearts were divided into four groups: group 1, 8-hr storage in UW solution; groups 2 and 3, 8- or 12-hr storage in HTK solution, respectively; and group 4, 12-hr storage in HTK solution with NCR. They were arrested and stored at 4 degrees C in each preservation solution. Following storage, they were reperfused and postpreservative function was measured to assess cardiac functional recovery. Concentrations of creatine phosphokinase, troponin-T, and lactate in the coronary perfusate were measured. Frozen tissue samples from groups 3 and 4 were analyzed for adenylate content and cGMP. The myocardial water content was also measured. The recovery of AF, CF, CO, SP, and RPP in group 2 was significantly improved compared with that in group 1 (P<0.05). The recovery of AF, CF, CO and HR in group 4 was significantly better than that in group 3 (P<0.05). Creatine phosphokinase leakage in group 2 and troponin-T leakage in group 4 were significantly reduced (P<0.05 vs. groups 1 and 3, respectively). Total adenine nucleotides and the adenylate energy charge in group 4 were well sustained (P<0.05 vs. group 3). These results suggest that HTK solution is more effective than UW solution for cardiac preservation, and that NCR provides still better protection.

Ischemic preconditioning improves cardiac functional recovery following preservation with University of Wisconsin solution.

Single or multiple brief periods of regional or global ischemia and reperfusion prior to a prolonged ischemic insult showed cardioprotective effects. Although this phenomenon (ischemic preconditioning [IPC]) has been described in ischemic reperfusion models, the effect of IPC on heart preservation has not been previously reported. We, thus, investigated the effect of IPC on heart preservation. Hearts isolated from male Wistar rats (250-350 g) were mounted on a Langendorff apparatus to estimate baseline function (aortic flow, coronary flow, cardiac output, heart rate, systolic pressure, and rate pressure product). All hearts were divided into 5 groups. In groups 1 and 4, the hearts were subjected to 8 and 12 hr of preservation, respectively. The hearts in group 2 were subjected to a single 2.5-minute cycle of normothermic global ischemic episode (IPC) before 8 hr of preservation. In groups 3 and 5, the hearts were subjected to two 2.5-min IPC cycles and stored for 8 or 12 hr. The hearts were arrested with University of Wisconsin solution and stored at 4 degrees C. Following storage, the hearts were reperfused and measured postpreservative function to assess cardiac functional recovery. Lactate and troponin-T leakage in the coronary perfusate was also measured. In group 3, the treatment of two 2.5-min IPC cycles significantly increased cardiac output, but the treatment of single 2.5-min IPC cycle did not affect the result. In the extended preservation group (group 5), the recovery (%) of both coronary flow and cardiac output were significantly increased compared with group 4. Furthermore, lactate leakage was significantly reduced in groups 2 and 3. These results suggest that IPC improves cardiac functional recovery following simple cold storage and has cardioprotective effects in rat heart preservation.

INHIBITION OF PLATELET AGGREGATION BY ENDOCARDIAL ENDOTHELIAL CELLS

We assessed the anti-platelet properties of endocardial endothelial cells (EECs) by measuring platelet aggregation after brief interaction with EECs isolated from the right ventricles of porcine hearts. Platelet aggregation in response to thrombin was significantly inhibited by brief incubation of platelet suspensions over EEC monolayers. Pretreatment of EECs with indomethacin restored platelet reaction but that with L-NAME and hemoglobin (Hb) did not. The PGI2 content of platelet suspensions after interaction with cultured EECs was significantly correlated with the inhibition of platelet aggregation. These results suggest that EECs inhibit platelet aggregation by releasing PGI2.

Successful 96-Hr cold-storage preservation of canine pancreas with UW solution containing the thromboxane A2 synthesis inhibitor OKY046.

Prostanoids, such as prostacyclin (PGI) and thromboxane A2 (TxA), have been recently suggested to play an important role in preservation-induced injury of pancreas grafts. We have previously shown that the TxA synthesis inhibitor OKY046 prevents a decrease of both the PGI/TxA ratio and blood flow in pancreas grafts after 24-hr preservation with Euro-Collins solution. In our present study, we analyzed whether OKY046 added to University of Wisconsin (UW) solution could extend successful cold-storage preservation of segmental canine pancreas grafts, compared with UW alone. We divided 30 dogs into four preservation groups: Group 1, UW solution for 72 hr (n = 7); Group 2, UW solution for 96 hr (n = 8); Group 3, UW solution plus OKY046 (10(-4) M) for 72 hr (n = 7); and Group 4, UW solution plus OKY046 (10(-4) M) for 96 hr (n = 8). After the cold storage period, segmental pancreas auto-transplantation with immediate completion pancreatectomy was done. Preservation was deemed successful if serum glucose less than 150 mg/dl was maintained for at least 5 days. Intravenous glucose tolerance tests and biopsies were done in those dogs with functioning grafts 14 days post-transplant. Successful preservation rates were as follows: Group 1, 57.1%; Group 2, 12.5%; Group 3, 100%; and Group 4, 75%. The mean K values (+/- standard error) were: Group 1, 1.54 +/- 0.13; Group 2, 0.59; Group 3, 1.54 +/- 0.14; and Group 4, 1.59 +/- 0.24 (not statistically different).(ABSTRACT TRUNCATED AT 250 WORDS)

Prurigo Nodularis Associated with Advanced Gastric Cancer: Report of a Case

In a male Japanese patient, prurigo nodularis (PN) appeared in association with gastric cancer. The cutaneous pruriginous lesions dramatically improved soon after total gastrectomy without any treatment for the skin lesions. Peripheral eosinophilia seen before the operation also rapidly disappeared. These data suggest that some cytokines involved in gastric cancer might have played an important role in the development of PN in our patient.

Heterotopic autotransplantation of a pancreas segment with enteric drainage after total or subtotal pancreatectomy for chronic pancreatitis

SummaryFour patients with chronic alcoholic pancreatitis and one patient with idiopathic chronic pancreatitis, who had total or subtotal distal pancreatectomies for persistent pain, underwent simultaneous autotransplantation of a pancreas segment to preserve the pancreatic function. The segment was autotransplanted heterotopically to the iliac fossa with anastomosis of the splenic vessels to the iliac vessels to prevent reinnervation, and the pancreatic duct was anastomosed to the intestine to preserve exocrine function. Postoperatively, the patency of the graft vessels was confirmed by angiography in every patients. Complete pain relief has been obtained in all patients with a followup duration of 4–89 mo. Except for one patient who had been treated preoperatively with insulin injections for diabetes, the patients remained normoglycemic without exogenous insulin administration and demonstrated satisfactory insulin secretion during a 75-g oral glucose tolerance test. An exocrine pancreatic diagnostant test usingp-aminobenzoic acid yielded nearly similar levels to the preoperative value for all patients. Heterotopic autotransplantation of the pancreas segment appears to be effective for preserving pancreatic function, as well as providing permanent pain relief for patients with chronic pancreatitis who require extensive resection of the pancreas.

Heterotopic autotransplantation of the distal pancreas segment after total pancreatectomy for cancer of the head of the pancreas.

Autotransplantation of the distal pancreas segment with pancreaticojejunostomy was performed in four patients with cancer of the head of the pancreas to preserve endocrine pancreatic function after extended total pancreatectomy. All patients had tumor involvement of both the celiac axis and the portal vein. The pancreatic graft was determined to be cancer-free by frozen section histologic and pancreatic juice cytologic examinations. The distal pancreas segment was autotransplanted to the iliac vessels heterotopically and placed in the extraperitoneal pocket to avoid untoward effects of any local recurrence or pancreatic leakage. This procedure, in the form of reconstruction, might be called modified subtotal pancreatoduodenectomy. Postoperatively, all patients remained normoglycemic without exogenous insulin administration, and their quality of life was considered satisfactory.