Relationship between ischaemic time and ischaemia/reperfusion injury in isolated Langendorff-perfused mouse hearts

Myocardial functional recovery and creatine kinase (CK) release following various periods of ischaemia were investigated in isolated mouse hearts. The hearts were perfused in the Langendorff mode with pyruvate-containing Krebs-Hensleit (KH) buffer under a constant perfusion pressure of 80 mmHg, and were subjected to either continuous perfusion or to 5, 15, 20, 25, 30, 45 or 60 min of global ischaemia followed by 45 min of reperfusion. In hearts subjected to ischaemic periods of 5, 15 or 20 min, there was a transient reduction in the left ventricular (LV) dP/dt max during the early phase of reperfusion, while the recovery at the end of reperfusion reached a level similar to that in hearts subjected to continuous perfusion. In hearts subjected to longer ischaemic periods, i.e. 25, 30, 45 or 60 min, the decrease in the cardiac performance was more pronounced and persistent, with significantly lower recovery in LV dP/dt max and higher LV end diastolic pressure (LVEDP) at the end of reperfusion than in the non-ischaemic hearts. There were no significant differences in the recoveries in coronary flow or in heart rate (HR) between groups. Similarly to the functional recovery, the release of CK showed a clear ischaemic length-related increase. In conclusion, the Langendorff-perfused isolated mouse heart could be a valuable model for studies of myocardial ischaemia/reperfusion injury. Future studies using gene-targeted mice would add valuable knowledge to the understanding of myocardial ischaemia/reperfusion injury.     

Cyclic fluctuations in the cardiac performance of the isolated Langendorff‐perfused mouse heart: pyruvate abolishes the fluctuations and has an anti‐ischaemic effect

During the development of a Langendorff preparation of isolated mouse hearts, hitherto undescribed cyclic fluctuations in left ventricular pressure and coronary flow were independently observed in three laboratories. Isolated mouse hearts were perfused with crystalloid glucose‐containing Krebs–Hensleit buffer in a constant pressure model, and left ventricular pressures were measured via an intraventricular balloon catheter. After acquiring technical skill in preparing the mouse hearts, the perfusionists observed that fluctuations in cardiac performance with a cycle period lasting 5–10 min occurred shortly after initiation of perfusion. Each fluctuation cycle consisted of a phase of increase and a phase of decrease. Synchronized with the fluctuations in left ventricular pressure, increases and decreases in dP/dt max took place. Analogous fluctuations in coronary flow occurred, with onset 1–2 min later than changes in left ventricular systolic pressure. In some preparations a gradual ST‐segment elevation was seen on the electrocardiogram during the systolic pressure increase phase. The amplitude of the fluctuations could be augmented by increasing the perfusion pressure, and reduced, but not abolished, by lowering the pressure. Changes in buffer calcium, magnesium, or sodium concentration did not alter the fluctuations, nor did any change of anaesthetics, mouse strain, or left ventricular drainage. Altering the perfusion mode from constant pressure to constant flow did not prevent the occurrence of the cyclic fluctuations. The hearts became stable and the fluctuations disappeared when the buffer was supplemented with 2 mm pyruvate. In the present study, pyruvate given throughout stabilization and reperfusion also markedly attenuated the ischaemic insult, as evidenced by the delayed ischaemic contracture and a reduced magnitude of ischaemic contracture. A cardioprotective effect was only visible at early reperfusion, did not affect the final functional recovery. In conclusion, a phenomenon of cyclic fluctuations in left ventricular pressure followed by fluctuations in coronary flow was observed in isolated mouse hearts. These could be abolished by adding 2 mm pyruvate to the perfusion buffer. Pyruvate in the buffer also markedly attenuated the post‐ischaemic deterioration of cardiac performance seen in this mouse model.     

Pretreatment with insulin before ischaemia reduces infarct size in Langendorff‐perfused rat hearts

Aim: To compare the possible role of Akt and mammalian target of rapamycin (mTOR) in mediating cardioprotection against ischaemia under three different conditions: (1) During ischaemic preconditioning (IPC), (2) when insulin was given as a pretreatment agent (InsPC) and (3) when insulin was given as a reperfusion cell survival agent (Ins_R). Methods: Isolated perfused rat hearts were subjected to IPC (3 × 5 min) or InsPC (50 mU mL^?1; 3 × 5 min), before 30 min of regional ischaemia followed by 120 min of reperfusion ± 1L‐6‐hydroxymethyl‐chiro‐inositol‐2‐[(R)‐2‐O‐methyl‐3‐O‐octadecylcarbonate] (HIMO) (20 μm ; Akt inhibitor) or rapamycin (1 nm ; mTOR inhibitor). In addition, insulin (3 mU mL^?1) was given at the onset of reperfusion, ±HIMO or rapamycin. Risk zone (R) and infarct size (I) were determined with Evans blue and tetrazolium staining respectively. Western blot analysis was performed on tissue from Langendorff‐perfused rat hearts and cell lysates from cultured HL1 cells. Results: IPC, InsPC and Ins_R treatment resulted in a significant reduction in infarct size compared to controls (all P < 0.05). This protective effect of IPC and insulin was abolished by the inhibitors. However, the putative Akt inhibitor, although capable of abolishing cardioprotection induced by insulin, was not able to inhibit insulin‐induced phosphorylation of Akt in Langendorff‐perfused rat hearts and cultured HL1 cells. The target for this compound therefore remains to be determined. Conclusion: IPC and insulin (either as InsPC or Ins_R) appear to activate mTOR, and this kinase seems to play an essential role in cardioprotection against ischaemia and reperfusion injury as rapamycin blocked the protection.     

Mitophagy imbalance in cardiomyocyte ischaemia/reperfusion injury

The rhythmic contraction of cardiomyocytes consumes a lot of energy. 90% of ATP in cardiomyocytes is produced by mitochondria. Maintenance of a healthy population of mitochondria by mitophagy is critical for cardiomyocyte survival and normal function. Mitophagy refers to selective removal of damaged mitochondria by autophagy mechanism. The process of mitophagy must be restricted to dysfunctional mitochondria and maintained at a balanced level. Disruption in the balance inevitably leads to cardiomyocyte injury and dysfunction. Accumulating evidence suggests that mitophagy plays a pivotal role in ischaemia/reperfusion‐induced cardiomyocyte injury. In this review, we focus on the current understanding of mitophgy in cardiomyocyte function, the implications for cardiomyocyte injury in response to ischaemia/reperfusion as well as their underlying potential mechanisms.     

Renal ischaemia/reperfusion injury: possible role of aquaporins

Renal ischaemia/reperfusion (I/R) injury is a common problem that occurs when blood flow is interrupted to the kidney in case of kidney transplantation, aortic cross-clamping and shock with subsequent resuscitation. Renal I/R injury is a complex conditions which includes the onset of an inflammatory process, which is associated with impairment of concentrating ability of the kidney and impairment of solute transport. Characteristically, renal I/R injury is associated with marked reduction in the protein expression of renal aquaporins (AQPs) mainly (AQP1, AQP2 and AQP3), and solute transporters were observed in this condition and could account for the impaired urinary concentration that observed in this condition. Recently, many agents were tested for a possible protective effect against this insult such as erythropoietin (EPO), α-melanocyte-stimulating hormone (α-MSH) and α-lipoic acid which were proved to prevent downregulation of AQPs and solute transporters. The aim of this short review is to outline the potential pathophysiological role of AQPs in renal I/R injury and to put a spotlight on the modulation of renal functions impairment in renal ischaemia by new drugs that prevent downregulation of AQPs.     

Role of l-arginine in preventing myocardial and endothelial injury following ischaemia/reperfusion in the rat isolated heart

The protective effect of l -arginine on ischaemia/reperfusion-induced myocardial injury was investigated in the rat isolated Langendorff perfused heart. Six groups of hearts subjected to 30 min global ischaemia and 30 min reperfusion received either vehicle, d -arginine, l -arginine, the nitric oxide (NO)-donor S-Nitroso-N-Acetyl-d, l -Penicillamine (SNAP), the inhibitor of NO formation N^G-nitro-l -arginine (l -NNA), or l -arginine plus l -NNA. The recoveries of left ventricular double product and coronary flow at the end of reperfusion were significantly higher in the l -arginine group (85±5 and 75±6%, respectively) than in the vehicle group (37±6 and 34±5%, respectively, P<0.05). During both the ischaemic and reperfusion periods, left ventricular end diastolic pressure was lower in the l -arginine group than in the vehicle group. Creatine kinase outflow and the area of no-reflow were smaller in the l -arginine treated hearts (P<0.01). There were no differences between vehicle and d -arginine treated groups. l -NNA did not affect recovery per se but abolished the protective actions of l -arginine. SNAP produced the same protective effects as l -arginine. Acetylcholine-induced endothelium-dependent vasodilation was reduced after ischaemia and reperfusion in the vehicle group but not in the l -arginine group. It is concluded that l -arginine reduces ischaemia/reperfusion-induced myocardial and endothelial injury. The results suggest that the beneficial effects of l -arginine are related to preserved synthesis and release of NO.     

Hyponatraemia aggravates cardiac susceptibility to ischaemia/reperfusion injury

Hyponatraemia is defined as a serum sodium concentration of <135 mEql/L and is the most common electrolyte disturbance in patients with chronic heart failure. We hypothesize that hyponatraemia may induce Ca²⁺ overload and enhance reactive oxygen species (ROS) production, which will exacerbate myocardial injury more than normonatraemia. We investigated the effect of hyponatraemia on the ability of the heart to recover from ischaemia/reperfusion episodes. Cardiomyocytes were obtained from 1‐ to 3‐day‐old Sprague Dawley rats. After isolation, cardiomyocytes were placed in Dulbecco's modified Eagle's medium (DMEM) containing low sodium concentration (110, 120, or 130 mEq/L) or normal sodium concentration (140 mEq/L) for 72 hours. Exposure of cardiomyocytes to each of the low‐sodium medium significantly increased both ROS and intracellular Ca²⁺ levels compared with the exposure to the normal‐sodium medium. In vivo, 8‐week‐old male Sprague Dawley rats were divided into four groups: control group (Con), furosemide group (Fur), low‐sodium diet group (Lsd) and both furosemide and low‐sodium diet group (Fur + Lsd). The hearts subjected to global ischaemia exhibited considerable decrease in left ventricular developed pressure during reperfusion, and the size of infarcts induced by ischaemia/reperfusion significantly increased in the Fur, Lsd and Fur + Lsd compared with that in the Con. Hyponatraemia aggravates cardiac susceptibility to ischaemia/reperfusion injury by Ca²⁺ overload and increasing in ROS levels.     

Macrophage involvement in the kidney repair phase after ischaemia/reperfusion injury

Macrophage infiltration is a common feature of the early phase of renal ischaemia/reperfusion injury. Indeed, it is generally regarded as the cause of tissue injury in this phase, although it is also clear that it can lead to tissue repair in other phases. In order to ascertain whether macrophages are directly involved in the repair/late phase, which follows the pro-inflammatory and injury process of renal ischaemia/reperfusion, we used two different approaches based on macrophage depletion. Firstly, we produced renal ischaemia in mice that were previously treated with clodronate liposome. Secondly, during reperfusion we re-injected RAW 264.7 to macrophage-depleted mice 24 h prior to sacrifice. The results showed that regeneration, as evaluated by stathmin and PCNA markers, was macrophage-dependent: it was blocked when macrophage depletion was provoked and recovered with macrophage re-injection. The cytokine profile revealed the influence of the inflammatory environment on kidney repair: pro-inflammatory cytokines (MCP-1, MIP-1alpha) increased during the early stages of reperfusion, coinciding with low regeneration, and the anti-inflammatory cytokine IL-10 increased during the longer periods of reperfusion when regeneration was more evident. We conclude that macrophages induce renal regeneration after ischaemia/reperfusion, depending on the inflammatory milieu.     

天麻素预处理对大鼠离体心脏缺血/再灌注损伤的保护作用

目的探讨天麻素对大鼠离体心脏缺血/再灌注(I/R)损伤的保护作用。方法 60只SD雄性大鼠随机分为正常对照组、缺血/再灌注组、天麻素预处理(10、50、100、200μmol/L)组,应用Langendorff离体心脏灌注系统建立心脏I/R损伤模型。除正常对照组外,各组分别进行平衡灌注、全心停灌/再灌处理,从心功能各项指标、心肌酶学、心肌梗死面积(TTC染色)及组织病理学(HE染色)变化4个层面评估天麻素预处理对大鼠离体心脏(I/R)损伤的影响,评价不同浓度天麻素预处理对心脏(I/R)损伤心肌的保护作用。结果与缺血/再灌注组相比,不同浓度天麻素预处理组均可改善缺血/再灌注损伤心功能的各项指标,包括左心室发展压(LVDP)、左室内压上升/下降最大速率(±dp/dtmax)和心率(HR);并降低冠脉流出液中肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)和肌钙蛋白(Trop-I)的活性,有效减少心肌梗死面积,其中以100μmol/L浓度的天麻素效果最显著(P0.05)。结论天麻素预处理对大鼠离体心脏缺血/再灌注引起的心肌损伤有保护作用,其中以100μmol/L的保护作用最为显著。     

人参皂苷Rg1预处理对大鼠离体心缺血/再灌注损伤的保护作用

目的:探讨人参皂苷Rg1对离体大鼠心缺血/再灌注(I/R)损伤的保护作用。方法:选取SPF级SD大鼠随机分为正常对照组、I/R组、人参皂苷Rg1(1、5、10、20μmol/L)处理组。利用Langendorff灌流系统建立大鼠离体心I/R损伤模型。IabOhart电生理系统实时监测心功能指标,血清生化检测心流出液中心肌酶含量,TTC染色法测定心肌梗死面积。结果:不同浓度人参皂苷Rg1均可改善心肌I/R损伤引起的左室发展压(LVDP)和左室内上升/下降最大速率(±dp/dt_(max))的下降,并降低流出液巾乳酸脱氢酶(LDH)、肌酸激酶同工酶(CK MB)、肌红蛋白(MYO)和肌钙蛋白I(TroI)的含量,显著减少心肌梗死面积。其中5μmol/L和10μmol/L浓度的人参皂苷Rg1对心的保护作用最显著。结论:人参皂苷Rg1具有药物预适应作用,改善心肌I/R损伤后的心肌生理功能,减少流出液中心肌酶的释放和心肌梗死面积,从而发挥抗心肌I/R损伤的保护作用。     

Various inotropic effects of angiotensin II in post‐ischaemic rat hearts depending on ischaemic time with possible involvement of protein kinase C

Aims: The present study investigated if the inotropic effect of angiotensin II (AngII) is altered during post‐ischaemic reperfusion in hearts subjected to mild and severe ischaemia. The possible involvement of protein kinase C (PKC) in the change in the inotropic effect was also investigated. Methods: Isolated Langendorff‐perfused rat hearts were perfused under constant flow with oxygenated Krebs–Henseleit buffer and paced at 360 beats min^?1. A saline‐filled balloon catheter inserted into the left ventricle was used for measurement of contractile force. In the first series of experiments, hearts were subjected to continuous perfusion, 15‐ or 25‐min global ischaemia followed by 45‐min reperfusion. At the end of reperfusion, 0.1 μmol L^?1 AngII was infused for 5 min. In a second series of experiments, AngII was infused in hearts subjected to 25‐min ischaemia followed by 45‐min reperfusion in the absence or presence of the PKC inhibitor chelerythrine chloride (5 μmol L^?1). Results: The current study demonstrates that AngII exerts a positive inotropic effect in normoxic hearts with an increase of left ventricular developed pressure (LVDP) by 11% (P < 0.05 vs. prior to AngII infusion). In post‐ischaemic hearts subjected to 15‐min ischaemia no effect of AngII was observed. In hearts subjected to 25 min of ischaemia, however, AngII evoked a negative inotropic response with a decrease of LVDP by 18% (P < 0.05 vs. prior to AngII infusion). The negative inotropic effect of AngII was inhibited by the PKC inhibitor chelerythrine chloride. Conclusions: AngII exerts negative inotropic effect in severely injured post‐ischaemic heart, possibly through the PKC pathway.     

Peroxisomal fatty acid oxidation capacity is more resistant to ischaemic and reperfusion injury than mitochondrial fatty acid oxidation capacity in feline hearts

We investigated ischaemic and postischaemic mitochondrial and peroxisomal fatty acid oxidation capacity, ATP levels and regional function in 40 anaesthetized open chest cats subjected to 10 or 40 min of regional myocardial ischaemia with or without 3 h of reperfusion (n=10 in each situation). Following 10 min of ischaemia, the mitochondrial fatty acid oxidation capacity measured in tissue extracts from ischaemic tissue (nmol min^-1 mg protein^-1) was reduced in both subepi- and subendocardium, but was normalized in reperfused tissue extracts from both wall layers (0.29±0.03 and 0.30±0.04 vs. 0.57±0.05 and 0.59±0.05, P<0.05). Peroxisomal fatty acid oxidation capacity in tissue extracts was unaffected by ischaemia and reperfusion. ATP levels and regional function measured in the LAD region was partly restored transmurally. After 40 min of LAD occlusion, mitochondrial fatty acid oxidation capacity was reduced, with higher activity in subepi- than in subendocardium (0.27±0.05 vs. 0.19±0.04, P<0.05). Reperfusion did not restore mitochondrial fatty acid oxidation capacity. Peroxisomal fatty acid oxidation capacity was increased in the ischaemic subendocardium compared with levels in non-ischaemic subendocardium (0.53±0.02 vs. 0.45±0.03, P<0.05), with normalization at the end of reperfusion. ATP levels were non-uniformly reduced during ischaemia and not repleted during reperfusion. Regional function recovered in circumferential segments but not in longitudinal segments following 40 min of ischaemia. In conclusion fatty acid oxidation enzymes seem to be more resistant to ischaemia in peroxisomes than in mitochondria. Mitochondrial fatty acid oxidation is fully reversible following shortlasting ischaemia, but remains depressed following prolonged ischaemia and reperfusion.     

The protective effects of L-arginine after liver ischaemia/reperfusion injury in a pig model

Hepatic ischaemia/reperfusion is characterized by circulatory and metabolic derangement, liver dysfunction, and tissue damage. To evaluate the role of L -arginine, a substrate of nitric oxide, in ischaemia/reperfusion injury, total liver ischaemia was induced for 120 min in 22 Landrace×Large White female pigs, which were randomly assigned to a treatment group (10 animals) or a control group (12 animals). An L -arginine bolus (540 mg/kg i.v.) was administered to the treatment group 1 h before clamping the hepatic hilum, at clamping, at reperfusion, and at 1 and 2 h after reperfusion. The control animals received normal saline and an i.v. infusion. Liver function tests and analysis of serum, erythrocyte, and tissue malondialdehyde contents were performed at commencement of laparotomy, before reperfusion, and at 30 min and 7 days after reperfusion. Liver biopsies were taken at laparotomy, at 30 min, and at 7 days after reperfusion for histological and ultrastructural examination. Assessment of apoptosis included in situ end-labelling analysis and DNA gel electrophoresis. Survival at 7 days was better in the treated animals than in the controls (9/10 vs. 7/12). Tissue malondialdehyde content, aspartate aminotransferase, and lactate dehydrogenase levels were lower in the treatment group, in which morphological changes were significantly less evident than in the controls 30 min after reperfusion. At 7 days, differences between the groups with respect to cell integrity were apparent only on ultrastructural analysis. Glycogen content, 7 days after reperfusion, was higher in the treatment group than in the controls: 70·25 per cent vs. 21·66 per cent positive hepatocytes (score 3 vs. score 1). Multiparametric analysis showed fewer apoptotic cells in the treatment group at all times. Our data show that the administration of L -arginine reduces damage to liver tissue after ischaemia/reperfusion injury in a pig model. This may be explained not only by the known vasodilator, anti-aggregation, and superoxide inactivation effects of increased nitric oxide release, but possibly also by some other action of L -arginine, such as its influence on cellular metabolism. © 1997 John Wiley & Sons, Ltd.     

Effects of sex,gonadectomy, and oestrogen substitution on ischaemic preconditioning and ischaemia–reperfusion injury in mice

Aim: Ischaemic preconditioning (IPC) has been demonstrated to protect heart function and viability, but has been predominantly studied in male animals. Methods: We studied a possible influence of sex and oestrogen for protection in IPC. Infarct size and heart function after 40 min global ischaemia and 60 min reperfusion with or without preceding classic IPC was investigated in Langendorff‐perfused hearts. Hearts were harvested from 10‐week‐old male and female C57BL6 mice with or without gonadectomy 6 weeks earlier, or gonadectomy and substitution with 17β‐oestradiol for 4 weeks (n = 104). Results: Classic IPC reduced depression of left ventricular developed pressure (P < 0.01), attenuated the increase of end‐diastolic pressure (P < 0.01), and reduced infarct size (P < 0.01) in hearts of untreated male mice, but failed to protect untreated females which had improved functional recovery and smaller infarctions than untreated males. After gonadectomy of female mice, developed pressure was reduced (P < 0.01) and infarct size increased (P < 0.01) compared with normal females, with no protection of preconditioning. The changes were not reversed by 17β‐oestradiol substitution. In hearts of gonadectomized males, the post‐ischaemic increase of end‐diastolic pressure was attenuated (P < 0.01), and enhanced after substitution with 17β‐oestradiol (P < 0.01). The preconditioning effect disappeared after gonadectomy and gonadectomy with substitution in male mice. Conclusion: There is a sex difference in evoking preconditioning in male and female mice which is only partially dependent on sex hormones.     

改构型酸性成纤维细胞生长因子对离体大鼠缺氧再灌注心脏的保护作用

目的：探讨maFGF对大鼠缺氧再灌注心脏的保护作用及其机制。 方法： 在Langendorff离体心脏灌流装置上建立缺氧再灌注模型，用BL-410生物机能实验系统记录左室发展压（LVDP）、左室内压上升/下降的最大速率（dp/dtmax、dp/dtmin），比较经maFGF和aFGF预处理，心肌缺氧再灌前后LVDP、dp/dtmax、dp/dtmin的变化，测定冠脉流出液中的LDH、MDA、SOD水平。 结果： maFGF和aFGF预处理均明显促进心肌缺氧再灌后心功能恢复，减少缺氧再灌注导致的LDH漏出、SOD降低和MDA升高。 结论： maFGF对缺氧再灌注心脏具有一定的保护作用，其作用机制可能与提高自由基清除酶活性及抑制脂质过氧化反应有关。     

Cardiodepressant mediators are released after myocardial ischaemia: modulation by catecholamines and adenosine

The interaction of recently characterized cardiodepressant mediators with catecholamines and adenosine after myocardial ischaemia was investigated using a model of sequential perfusion of two isolated guinea-pig hearts. Sequential perfusion was initiated after 10, 20, and 30 min (group I, II, and III) of global ischaemia in the first heart. At the onset of sequential perfusion LVdP/dt_max and _min of Heart II decreased by 46 and 44% in group I, by 28 and 34% in group II, and increased by 60 and 24% in group III. Infusion of the β₁-receptor antagonist metoprolol (2.8 μmol L^–1) into Heart II did not modulate contractile changes after 10 min of ischaemia in Heart I, prevented the attenuation of the cardiodepressant effect after 20 min of ischaemia, and completely reversed the positive inotropic effect after 30 min of ischaemia. The A1- and A2-receptor antagonists DPCPX (2 μmol L^–1) and DMPX (20 μmol L^–1) enhanced the positive inotropic and lusitropic effects in Heart II (LVdP/dt_max +154%, LVdP/dt_min +71%) during sequential perfusion after 30 min of ischaemia in Heart I. It is concluded that the effects of cardiodepressant mediators released after myocardial ischaemia are counteracted by a time-dependent release of catecholamines. Endogenous cardiac adenosine, in turn, attenuates the modulatory effects of catecholamines.     

Heparin binding epidermal growth factor in renal ischaemia/reperfusion injury

The epidermal growth factor (EGF) receptor and its ligands are crucially involved in the renal response to ischaemia. We studied the heparin binding‐epidermal growth factor (HB‐EGF), a major ligand for the EGF receptor, in experimental and human ischaemia/reperfusion injury (IRI). HB‐EGF mRNA and protein expression was studied in rat kidneys and cultured human tubular (HK‐2) cells that were subjected to IRI and in human donor kidneys during transplantation. The effect of EGF receptor inhibition was investigated in vivo and in vitro. Furthermore, urinary HB‐EGF protein excretion was studied after renal transplantation. Finally, HB‐EGF KO and WT mice were subjected to IRI to study the role of HB‐EGF in renal injury. HB‐EGF mRNA was significantly up‐regulated in the early phase of IRI in rats, cells, and human donor biopsies. Treatment with PKI‐166 reduces macrophage accumulation and interstitial α‐SMA in the early phase of IRI in rats. In vitro, PKI‐166 causes a marked reduction in HB‐EGF‐induced cellular proliferation. Urinary HB‐EGF is increased after transplantation compared with control urines from healthy subjects. HB‐EGF KO mice subjected to IRI revealed significantly less morphological damage after IRI, compared with WT mice. We conclude that IRI results in early induction of HB‐EGF mRNA and protein in vivo and in vitro. Absence of HB‐EGF and inhibition of the EGF receptor in the early phase of IRI has protective effects, suggesting a modulating role for HB‐EGF. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Liver transplantation in man: morphometric analysis of the parenchymal alterations following cold ischaemia and warm ischaemia/reperfusion

Ischaemia and reperfusion phases represent critical events during liver transplantation. The purpose of this study was to describe morphological alterations of both vascular and parenchymal compartments after ischaemia and reperfusion and to evaluate the possible relationship between morphometric parameters and biochemical/clinical data. Three needle biopsies were drawn from 20 patients who underwent orthotopic liver transplantation. The first biopsy was taken before flushing with preservation solution, and the second and the third to evaluate respectively the effects of cold ischaemia and of warm ischaemia/reperfusion. Biopsies were examined by an image analyser and morphometric parameters related to the liver parenchyma were evaluated. At the second biopsy we observed a decrease of the endothelium volume fraction while the same parameter referred to the sinusoidal lumen achieved a peak value. The hepatocytes showed a lower surface parenchymal/vascular sides ratio. This parameter was reversed at the end of the reperfusion phase; furthermore the third biopsy revealed endothelial swelling and a decreased volume fraction of the sinusoidal lumen. The results quantify the damage to the sinusoidal bed which, as already known, is one of the main targets of cold ischaemia; warm ischaemia and reperfusion accentuate endothelial damage. The end of transplantation is characterised by damage chiefly to parenchymal cells. Hepatocytes show a rearrangement of their surface sides, probably related to the alterations of the sinusoidal bed. In addition, the fluctuations of morphometric parameters during ischaemia/reperfusion correlate positively with biochemical data and clinical course of the patients.     

Liver transplantation in man: morphometric analysis of the parenchymal alterations following cold ischaemia and warm ischaemia/reperfusion

Ischaemia and reperfusion phases represent critical events during liver transplantation. The purpose of this study was to describe morphological alterations of both vascular and parenchymal compartments after ischaemia and reperfusion and to evaluate the possible relationship between morphometric parameters and biochemical/clinical data. Three needle biopsies were drawn from 20 patients who underwent orthotopic liver transplantation. The first biopsy was taken before flushing with preservation solution, and the second and the third to evaluate respectively the effects of cold ischaemia and of warm ischaemia/reperfusion. Biopsies were examined by an image analyser and morphometric parameters related to the liver parenchyma were evaluated. At the second biopsy we observed a decrease of the endothelium volume fraction while the same parameter referred to the sinusoidal lumen achieved a peak value. The hepatocytes showed a lower surface parenchymal/vascular sides ratio. This parameter was reversed at the end of the reperfusion phase; furthermore the third biopsy revealed endothelial swelling and a decreased volume fraction of the sinusoidal lumen. The results quantify the damage to the sinusoidal bed which, as already known, is one of the main targets of cold ischaemia; warm ischaemia and reperfusion accentuate endothelial damage. The end of transplantation is characterised by damage chiefly to parenchymal cells. Hepatocytes show a rearrangement of their surface sides, probably related to the alterations of the sinusoidal bed. In addition, the fluctuations of morphometric parameters during ischaemia/reperfusion correlate positively with biochemical data and clinical course of the patients.