The effect of nifedipine, a calcium channel blocker, on liver ischemia in dogs

This study was undertaken in order to determine whether the administration of nifedipine, a calcium channel blocker, could protect the liver from ischemic damage and to investigate its effect on the hepatic cellular energy status and cardio-vascular system after 60 minutes of hepatic ischemia in dogs. The ischemia was induced by temporarily clamping the portal vein and hepatic artery. One group of animals (n = 17) received nifedipine (5 micrograms/kg body weight) intravenously 15 minutes before the induction of liver ischemia, which was continued at a dose of 0.2 microgram/kg body weight/min throughout the ischemic period, and for an additional 30 minutes afterwards. Control dogs (n = 16) were not given nifedipine and survival was observed over seven days. The survival rate was 83 per cent in the nifedipine treated animals and 0 per cent in the control animals. Serum glutamic oxaloacetic transaminase levels were greatly increased following ischemia, and they were significantly lowered with the nifedipine treatment. The hepatic energy charge decreased remarkably during the hepatic ischemia, however it increased gradually after declamping but did not returned to its preoperative value in either group until one hour later and then it was higher in the nifedipine treated animals than in the control animals. Cardiac index and portal venous blood flow ratio remained higher in the nifedipine treated animals than in the control animals, after the ischemic period. These results suggest that nifedipine may have a powerful cytoprotective effect and that the period of warm hepatic ischemia could be prolonged with its use.     

The calcium channel blocker nifedipine fails to inhibit leucocyte elastase release during cardiopulmonary bypass

Circulating concentrations of leucocyte elastase were measured in 16 adult patients undergoing cardiopulmonary bypass (CPB) with a flat-sheet membrane oxygenator. Eight patients (Group I) received the calcium channel blocker nifedipine (9 µmUg · kg^-1 · h^-1) during CPB. Eight patients (Group II) did not receive any calcium channel blocker during surgery and served as the control group. Elastase concentrations were measured at 7 time points: 2 before, 2 during, and 3 after CPB. The bypass procedure was associated with elevation in elastase concentrations (P<0.001). Comparing to baseline values elastase concentrations were significantly elevated (P<0.05) 60 min after the start of CPB and on all measurements done after CPB. Elastase concentrations correlated with the duration of CPB (rs = 0.76, P<0.001), and were not influenced by nifedipine infusion as revealed by comparing the two groups. This study demonstrates moderate elastase release during CPB with a fiat-sheet membrane oxygenator and fails to confirm inhibition of elastase release by nifedipine infusion during CPB.     

Preliminary study of the protective effect of the calcium channel blocker, nifedipine, on adriamycin-induced tissue injury

The effect of nifedipine, an oral calcium-channel blocker, on adriamycin-induced wound healing was studied. Nifedipine was administered to animals prior to treating with adriamycin. The healing strengths of cecal, fascial, and skin anatomoses were measured. Animals treated with adriamycin alone had significant decreases in healing strength compared to controls: for cecum at postoperative days (POD) 7 and 14; for skin at PODs 14, 21, and 28; for fascia at POD 28. Overall, nifedipine reduced the impact of adriamycin injury on the strength of healing incisional anastomoses. Nifedipine also appeared to protect collagen synthesis at anastomotic sites from adriamycin-induced impairment.     

Chronic use of the calcium channel blocker nifedipine has no significant effect on bone metabolism in men

Calcium channel blockers have been reported to have such diverse effects on reduction in protein synthesis, diminished incorporation of proline into new collagen, and decreased hormone release in vitro. The chronic affect of the calcium channel blocker nifedipine was examined in vivo to determine the possible impact of pharmacologic calcium channel blockade on bone metabolism. Eleven Caucasian males treated with an average of 40 mg/d nifedipine for an average of three years were compared to 11 control males matched for age, height, weight, activity level, cardiovascular status, and calcium intake. No significant differences between groups were noted in bone mineral density at the lumbar spine (L2-4), proximal femur (femoral neck, Ward's triangle and trochanter), and proximal and distal radius. There were also no significant differences in parameters of bone turnover (alkaline phosphatase, osteocalcin, urine calcium/creatinine, and hydroxyproline/creatinine ratio), or hormones that might affect calcium metabolism and bone (testosterone, PTH, 25(OH) vitamin D, and calcitonin). In summary, chronic nifedipine use in males is not associated with either a beneficial or adverse effect on bone metabolism.     

钙通道阻滞剂对未成熟心肌的保护作用

目的 观察钙通道阻滞剂对未成熟心肌的保护效果。方法 使用改良的非再循环式Langendorff离体心灌注装置，比较未使用盐酸尼卡地平和分别在缺血前，低温缺血停跳时，复灌初期3个不同时间给与盐酸尼卡地平者的心功能和心肌酶变化，测定缺血后心肌ATP，总钙含量，心肌含水量，观察心肌和冠状动脉内皮细胞结构的变化。结果 实验组的各项指标及对心肌及血管内皮结构保护明显优于对照组，实验组间差别无显著性意义。结论 使用钙通道阻滞剂可以对未成熟心肌产生良好的保护作用。     

钙拮抗剂对环孢素A所致药物性牙龈增生的协同作用

目的 探讨钙拮抗剂对环孢素A(CsA)所致药物性牙龈增生的协同作用.方法 130例服用CsA的肾移植受者,根据术后是否联合使用钙拮抗剂,分为钙拮抗剂组和未使用钙拮抗剂(对照组),记录和分析两组受者的年龄、性别、牙周指数、牙龈增生情况及严重程度、服用CsA的时间和剂量、血CsA浓度及血清肌酐等临床指标,并对牙龈增生者与牙龈未增生者进行进一步分析;分析使用不同钙拮抗剂者牙龈增生的发生率和严重程度.结果 钙拮抗剂组牙龈增生发生率为60%(44/73),显著高于对照组的39%(22/57,P＜0.05);钙拮抗剂组轻度牙龈增生受者的比例为37%,显著高于对照组的19%(P＜0.05);两组发生中、重度牙龈增生受者的比例差异无统计学意义(P＞0.05).两组受者中,牙龈增生者的牙龈菌斑指数和乳头出血指数均显著高于牙龈未增生者(P＜0.05),牙龈菌斑指数和乳头出血指数与牙龈增生严重程度呈正相关(P＜0.01).联合使用硝苯地平的受者,其牙龈增生发生率(77%)高于使用氨氯地平(57%)和非洛地平(50%)的受者.结论 联合使用钙拮抗剂对CsA所致药物性牙龈增生具有明显的协同作用;服用CsA的肾移植受者应避免使用硝苯地平以防止可能发生的牙龈增生.     

The protective effect of diltiazem, a calcium channel blocker on myocardial ischemia during open heart surgery--an analysis of electrolyte changes in myocardial cells

This study was designed to analyze the electrolytes changes in myocardial cells, and to clarify the effect of diltiazem, a calcium channel blocker on myocardial ischemia during open heart surgery. Thirty patients who underwent open heart surgery using cold glucose-insulin-potassium (GIK) cardioplegic solution were divided into following three groups. C group: diltiazem was not administered. CD group: cardioplegic solution containing diltiazem 7.5 mg/L was used. DP group: diltiazem 1.5 micrograms/kg/min was given continuously by intravenous administration from the day before operation to the day after operation. Atrial wall biopsies were performed before aortic cross clamp (non-ischemic status), after 60 minutes' ischemia, and 5 minutes after releasing aortic cross clamp (reperfusion). The specimens were freshly frozen and measured for various electrolytes by means of X-ray microprobe analysis. In C group, potassium level decreased during both ischemia and reperfusion, while calcium level increased during ischemia and significantly increased during reperfusion period. In DC and DP groups, calcium accumulation during reperfusion was suppressed, and potassium level which had been lowered during ischemia recovered to the level of non-ischemic status during reperfusion. Sodium and chlorine showed an increase during ischemia in each group. However, sodium accumulation in DC and DP groups tended to recover during reperfusion. DP and DC groups were considered to be superior to C group in terms of cardiac index and left ventricular work. This may be due to afterload reduction as evidenced by low systemic vascular resistance. Intracellular electrolytes environment during reperfusion and hemodynamics during early postoperative periods were excellent in DP group. CPK-MB was significantly lower in both CD and DP groups than in C group. These data suggested that diltiazem could suppress intracellular calcium accumulation and keep homeostasis of sodium-potassium pump mechanism in membrane during reperfusion. It is concluded that diltiazem is useful to protect myocardium from ischemia during open heart surgery.     

冷缺血对大鼠小体积肝移植肝再生的影响

目的探讨冷缺血对大鼠小体积肝移植术后肝再生的影响.方法本组在2002年9月～2004年8月利用大鼠肝总量30%原位肝移植模型,实验分为肝总量70%肝切除组(C组)和冷缺血1、3、5 h组(E1、E2、E3组),观察1w生存率及肝重量/受体原肝重量比值(EGW/RLW),并检测术后1、2、3、7d肝细胞增殖活性及肝组织学变化.结果E1组1w生存率及EGW/RLW分别达100%和95%,均明显高于E2、E3组(P均＜0.05);E1、E 、E3组均于术后2d达到增殖高峰,其中E1组峰值显著高于E2、E3组(P＜0.001),且与C组峰值无差异(P＞0.05);组织学检查见E1组肝细胞核分裂明显活跃.结论冷缺血1 h的小体积供肝和70%肝切除后肝脏具有同样的增殖活性,仅增殖高峰稍晚;冷缺血超过3h严重影响小体积供肝的再生能力和受者的存活率.     

Pattern of ischemia reperfusion injury in a mouse orthotopic liver transplant model

BACKGROUND: The molecular pathways of ischemic injury after liver transplantation are complex and difficult to dissect because of the presence of many variables. Transgenic and genetically deficient strains of mice provide ideal models for the study of the contribution of a single gene product in biological processes in vivo. Although well described in rats, prolonged preservation has not been studied in a mouse model of orthotopic liver transplantation (mOLT). The aim of this study was to establish a model of cold ischemia and reperfusion injury in mOLT and describe the pattern of the regenerative response to various lengths of cold storage. MATERIALS AND METHODS: mOLT was performed using a syngeneic combination. Grafts were preserved at 4 degrees C in University of Wisconsin (Viaspan) solution for increasing periods of cold preservation. After cold storage, the liver grafts were transplanted and recipient survival was monitored. Hepatocellular injury was determined by histology, and the regenerative response was quantitated by interleukin 6 upregulation and DNA replication. RESULTS: Long-term survival was 100%, 100%, 88%, and 0% for cold preservation of 1, 4, 8, and 16 h, respectively. Grafts with short preservation times (1 and 4 h) demonstrated limited injury and a weak regenerative response, with slight IL-6 early upregulation and minimal cell division. Eight hours of cold ischemia resulted in prominent injury and an intense regenerative response accompanied by significant IL-6 upregulation and DNA synthesis. Sixteen hours of storage resulted in all recipients succumbing to liver failure, with histology showing extensive hepatic necrosis. CONCLUSIONS: This study demonstrated the feasibility of using the mOLT model for the study of molecular mechanisms associated with recovery from cold ischemia and reperfusion injury. Increasing lengths of cold ischemia correlate with progressive tissue damage whereas recovery is associated with a regenerative response that correlates with the severity of injury.     

丙氨酰-谷氨酰胺二肽保护大鼠肝脏缺血再灌注损伤的实验研究

目的探讨丙氨酰-谷氨酰胺二肽(Ala-Gln)对肝脏缺血再灌注损伤(HIRI)的保护作用.方法采用大鼠HIRI模型(Pringle's法阻断入肝血流30 min),分谷氨酰胺组(G组)及对照组(C组),检测再灌注后血清肝生化酶、肝组织还原型谷胱甘肽(GSH)及超氧化物歧化酶(SOD)水平,对肝组织进行光镜与电镜检查,并计算术后24 h生存率.结果再灌注1h,G组血清ALT(499.25±120.84)U/L、LDH(6 956.00±2 443.93)U/L的水平均显著低于C组(ALT823.56±328.71,P<0.05;LDH11 715.31±2 993.50,P<0.01);再灌注24 h,两组血清ALT、LDH的水平均有显著恢复,但G组(ALT176.69±151.84;LDH415.38±213.68)水平仍显著低于C组(ALT548.25±257.25;LDH1 958.50±687.32;P<0.01).再灌注1 h及24 h,G组GSH的水平分别为(1 216.09±152.78)μg·g-1·p、(899.73±57.75)μg·g-1·p,均明显高于C组(分别为856.68±117.64,P<0.01;800.50±94.79,P<0.05);两组SOD的活性无统计学差异.G组肝脏组织学与细胞学损害均明显轻于C组.G组术后24h生存率为78.57%(11/14),明显高于C组的45.45%(10/22)(P<0.05).结论 Ala-Gln(Gln)对HIRI具有保护作用,而这种保护作用部分是通过维持肝脏组织中GSH的含量来介导的.     

The platelet activating factor as a pivotal mediator of shock after liver ischemia

Liver failure is often accompanied by shock, which is usually refractory to conventional vasopressive therapy, and it is believed that some potent chemical mediators are involved in this process. The platelet activating factor (PAF) is a newly discovered inflammatory mediator that has a remarkable hypotensive action. In the present study, the possible role of PAF in shock after ischemic liver failure was investigated. Partial hepatic ischemia was induced in Wistar rats by clamping the hepatic afferent vessels to almost 70% of the whole liver for 90 min. One group of rats was pretreated with 10 g/kg of TCV-309, a PAF antagonist. Pretreatment with TCV-309 inhibited the shock that ultimately occurred in the untreated rats; the survival rate 16h after hepatic ischemia was 20% in the untreated control group but 100% in the group pretreated with TCV-309. The level of PAF in the plasma after hepatic ischemia was 2,939±2,412 pg/ml, which was significantly higher than that of the surgical control (920±188 pg/ml). These findings strongly suggest that anoxical disintegration of the liver derives PAF which causes shock. Thus, a PAF antagonist is expected to be an effective prophylactic treatment for patients who are at risk of developing shock from an ischemic liver.     

Increase in survival time of liver transplants by protease inhibitors and a calcium channel blocker, nisoldipine

Kupffer cells are activated by calcium and release a variety of toxic mediators, including proteases. The purpose of these studies, therefore, was to determine if protease inhibitors and a calcium channel blocker could increase survival time in the rat model of orthotopic liver transplantation. Survival for 30 days was greater than 90% in this model when livers were stored for 1 hr in Ringer's solution (survival conditions)--however, grafts stored for 4 hr in Euro-Collins solution or 8 hr in University of Wisconsin (UW) solution survived postoperatively only 1.2 and 0.7 days, respectively (nonsurvival conditions). When livers were stored for 4 hr in Euro-Collins containing a cocktail of protease inhibitors (leupeptin, pepstatin A, phenylmethylsulfonyl fluoride, 20 ng/ml each; diisopropyl fluorophosphate, 100 microM) and subsequently transplanted, however, survival time was increased significantly to 11.5 days. Inclusion of a calcium channel blocker, nisoldipine (1.4 microM), in the protease inhibitor cocktail increased survival time to 23 days. Actually, nisoldipine alone increased survival time to 25 days. Nisoldipine alone also increased survival time in livers stored for 8 or 16 hr in UW solution to between 15 and 20 days. Serum transaminase levels reached peak values greater than 2400 U/L one day postoperatively in the nonsurvival groups, and liver injury assessed histologically was apparent. Under these conditions, pulmonary infiltration of inflammatory cells was observed in about 60% of the lungs examined and was associated with massive bleeding. Inclusion of the protease cocktail, nisoldipine, or both in the storage solutions decreased maximal SGOT levels and injury to both liver and lung significantly by about 50% postoperatively. Nisoldipine also decreased phagocytosis of carbon particles by the perfused liver 2- to 3-fold following storage under nonsurvival conditions (half-maximal effect = 0.3-0.4 microM nisoldipine). Moreover, nisoldipine improved hepatic microcirculation. It accelerated blood flow into the liver, as indexed by hemoglobin reflectance from the liver surface. These data support the hypothesis that Kupffer cells are activated early in the sequence of events that causes graft failure leading to endothelial cell-mediated alterations in the microcirculation. This work demonstrates clearly that dihydropyridine-type calcium channel blockers such as nisoldipine may be clinically useful in storage solutions for liver prior to transplantation.     

Effects of calcium antagonists in hypertensive patients with renal dysfunction: a prospective, randomized, parallel trial comparing benidipine and nifedipine

BACKGROUND: Although calcium antagonists, derived from dihydropyridine (DHP), are important agents in achieving control in a majority of patients with high blood pressure and renal disease, there are no comparative data regarding their inhibitory effects on the progression of renal dysfunction in Japan. METHODS: Benidipine and nifedipine retard both calcium antagonists derived from DHP and were compared in terms of their inhibitory effect on the progression of renal dysfunction in hypertensive patients. The primary end-points were defined as 1.5 times the serum creatinine value at baseline, progression to end-stage renal failure (ESRF) necessitating dialysis or renal transplantation, and death. RESULTS: During the study period, a significant decline in blood pressure was observed in the two groups, with no significant difference between them. The worsening of nephropathy was significantly inhibited in the benidipine group as compared with the nifedipine retard group (log-rank test: P = 0.014, Wilcoxon's test: P = 0.022). Among the subjects who reached a primary end-point, one (33%) in the benidipine group and five (50%) in the nifedipine retard group were placed on haemodialysis within 1 year. CONCLUSION: It appears that benidipine inhibits the progression of hypertensive renal diseases more effectively than nifedipine retard.     

热休克蛋白70对肝缺血再灌注损伤的作用及机制探讨

目的 探讨热休克蛋白70（Heat shock protein 70,HSP70）对大鼠肝缺血再灌注损伤的作用及机制。方法 实验大鼠分为持续阻断组、间断阻断组和假处理组。用免疫金银法观察再灌注1h后肝组织HSP70蛋白的表达,并检测其肝细胞及线粒体功能、肝组织内钙和脂质过氧化物（Lipid peroxide,LPO）含量,以及超氧化物歧化酶（Superoxide dismuase,SOD）活性。结果 HSP70蛋白在持续性缺血再灌注后无表达,肝细胞功能、线粒体功能和SOD活性均显著下降,而肝组织内钙和LPO值均显著升高。间断性血流阻断组则有HSP70蛋白的合成表达,该组与假处理组的上述各项指标的差异均无显著意义。结论HSP70蛋白在肝缺血再灌注后的诱导产生有利于保护肝细胞及线粒体的功能,该效应与细胞内钙稳定和SOD活性增高有关。     

Calcium mobilization in liver transplantation graft with warm ischemia

The influence of warm ischemia on calcium mobilization in liver transplantation was investigated. Twenty-four porcine orthotopic liver transplantations were performed by a temporary portal arterialization technique. Swine were divided into three groups according to warm ischemia time; I (0 min,n=9), II (30 min,n=8), and III (60min,n=7). Ionized calcium was measured in arterial and hepatic venous blood, in initial perfusate, and in initial perfused blood. In group I, all the pigs survived, while in group III all succumbed. In group II, four survived and four died. Ionized calcium level in influx showed no differences, but the level in the initial perfusate in group I was significantly higher than that in group III. The level in the initial perfused blood in group I was significantly higher than levels in groups II and III. Retrospective analysis in group II showed that ionized calcium value in the initial perfused blood in the survivors was significantly higher than that in the non-survivors. A substantial amount of ionized calcium accumulated after revascularization in the graft loaded with warm ischemia, and, in group II, significantly more ionized calcium accumulated in the non-survivors.     

钙离子通道阻滞剂在预防他克莫司肾毒性中的作用

目的 观察他克莫司(FK506)肾毒性模型中钙离子代谢的变化情况,探讨钙离子通道阻滞剂地尔硫草(Dil)对FK506肾毒性的预防作用.方法 按公式将肾移植术后FK506、环孢素(CsA)和Dil的首剂治疗剂量换算成大鼠的治疗剂量.雄性SD大鼠24只随机分成对照组、CsA组(25 mg·kg-1·d-1)、FK506组(0.8 mg·kg-1·d-1)和FK506加Dil组(0.8 mg·kg-1·d-1及8 mg·kg-1·d-1),每组6只,用药4周后建立各组大鼠肾毒性模型.观察各组大鼠SCr、血电解质、肾组织的病理改变(HE染色)、电子显微镜F肾脏细胞内超微结构的改变.结果 CsA组和FK506组大鼠SCr值分别为(36.00±2.61)和(34.17±4.54)μmol/L,均高于FK506加Dil组和对照组[(28.50±2.07)和(29.17±3.43)μmol/L,P＜0.05].CsA组和FK506组大鼠血钙浓度分别为(2.00±0.04)和(2.05_4-0.04)mmol/L,均低于FK506加Dil组和对照组(P＜0.05).CsA组和FK506组均可观察到肾小管细胞轻微肿胀及空泡变性、线粒体肿胀及空泡化等病理改变.与FK506组和CsA组相比,FK506加Dil组上述各项指标的变化明显减轻或接近正常.结论 钙离子代谢紊乱可能介导了FK506引起的肾毒性,Dil可用于预防FK506的肾毒性.     

Effects of the calcium channel blocker nifedipine on epiphyseal growth plate and bone turnover: A study in rabbit

Summary The potential effects of a calcium channel blocker (nifedipine) on epiphyseal growth plate and bone remodeling have been investigated in growing rabbits. The treated group received 6 mg/kg/day nifedipine twice daily by gavage for 10 weeks. An untreated group was used as control; with this dose, neither toxic effects nor decrease in the body weight have been observed. No modifications of blood phosphocalcic parameters have been found. In the treated group there is a significant lower cancellous bone volume, lower osteogenesis, shorter labeled perimeters, and lower mineral apposition rate than in the control group. Epiphyseal growth plate thickness is lower than in the untreated animals and considerable morphological changes are observed in the growth zone compared with the control group. A decrease in the growth of humerus length was found. In conclusion, nifedipine affects bone physiology, especially with consequences on bone growth. These effects appear to be quantitatively important, and there is the possibility of bone side effects on therapeutic use in humans, especially in young subjects.     

Kupffer细胞在肝移植缺血再灌注损伤中的双重作用

Kupffer细胞足定居于肝内的巨细胞,在月十移植缺血再灌注损伤中发挥着重要的作用,门静脉恢复血流后刺激Kupffer细胞激活,释放活性氧族、多种炎性介质和细胞因子,对肝脏造成损伤.另一方面又可上调HO-1的表达,保护肝脏缺血再灌注损伤,因此,Kupffer细胞在肝移植缺血再灌注损伤中发挥着双重效应.