Ischaemic preconditioning protects against ischaemia/reperfusion injury: emerging concepts.

INTRODUCTION: Ischaemic preconditioning (IP) has emerged as a powerful method of ameliorating ischaemia/reperfusion (I/R) injury to the myocardium. This review investigates whether this phenomenon is universally applicable in modulating I/R injury to other tissues. METHODS: A Medline search was conducted to identify both animal and human studies that described IP-induced protection from I/R injury in a variety of non-cardiac organ systems. Particular emphasis was placed on elucidation of underlying physiological concepts. RESULTS AND CONCLUSIONS: IP utilises endogenous mechanisms in skeletal muscle, liver, lung, kidney, intestine and brain in animal models to convey varying degrees of protection from I/R injury. To date there are few human studies, but recent reports suggest that human liver, lung and skeletal muscle acquire similar protection after IP. Specifically, preconditioned tissues exhibit reduced energy requirements, altered energy metabolism, better electrolyte homeostasis and genetic re-organisation, giving rise to the concept of 'ischaemia tolerance'. IP also induces 'reperfusion tolerance' with less reactive oxygen species and activated neutrophils released, reduced apoptosis and better microcirculatory perfusion compared to non-preconditioned tissue. Systemic I/R injury is also diminished by preconditioning. IP is ubiquitous but more research is required to fully translate these findings to the clinical arena.     

血红素氧合酶1基因转移对大鼠肾缺血再灌注损伤的防护作用

目的探讨血红素氧合酶1(HO-1)基因转移对大鼠自体移植肾缺血再灌注损伤的保护作用。方法构建HO-1腺病毒表达载体,经肾动脉灌注转染26只大鼠(实验组)移植肾,4℃保存24h后行自体移植,移植后5d切除对侧肾脏;以25只大鼠为对照。于移植后3h、3d,应用逆转录聚合酶链反应(RT-PCR)及免疫组织化学方法检测移植肾HO-1基因及蛋白的表达;应用酶联免疫吸附试验(ELISA)法测定肾组织匀浆中HO-1蛋白的含量(以吸光度值表示)。结果移植后3h及3d,实验组移植肾HO-1mRNA的表达强度分别为0·65±0·11及0·86±0·17,而对照组分别为0·09±0·01及0·15±0·02,两组相比差异具有统计学意义(t=14·38,11·73,P均<0·05);实验组移植肾HO-1蛋白含量分别为(297±61)及(468±51)ng/g,而对照组分别为(98±30)及(155±31)ng/g,两组相比差异具有统计学意义(t=8·27,14·83,P均<0·05)。与对照组相比实验组移植肾病理改变明显减轻(P<0·05),血肌酐水平明显降低(t=8·41,P<0·05)。结论腺病毒载体可成功介导HO-1基因对大鼠肾脏的转移,对自体移植肾缺血再灌注损伤具有保护作用。     

上调intermedin表达对大鼠肾脏缺血再灌注的保护作用

目的 观察上调肾脏intermedin( IMD)表达对大鼠肾脏缺血再灌注(I/R)的影响.方法 24只健康雄性Wistar大鼠随机分为假手术组、肾脏I/R组、IMD+I/R组、空质粒+I/R组,每组6只.所有动物于I/R术24h后杀检,取肾组织进行光镜检查,留取血清测定尿素氮(BUN)和血清肌酐(Scr)的浓度.免疫组织化学方法、半定量RT-PCR、Western印迹检测肾组织IMD表达及部位.Western印迹测定内皮素1(ET-1)、肿瘤坏死因子α(TNF-α)蛋白的表达.结果 HE、PAS染色结果显示,I/R组肾小管及间质病理损伤显著重于假手术组,IMD+I/R组小管间质损伤程度较肾脏I/R模型组及空质粒+I/R模型组明显减轻(1.5±0.8比7.6±2.3和7.0±1.8,均P＜0.05].与假手术组[(BUN 3.85±0.21 mmol/L,Scr(48.67±3.61) μmol/L相比,I/R组、IMD+I/R组以及空质粒+I/R组BUN(10.13±2.14) mmol/L,( 7.73±1.03) mmol/L,( 9.77±1.92) mmol/L和Scr(80.33±7.15) μmol/L,(58.50±:3.27)μmol/L,(75.67±7.58) μmol/L均明显升高(均P＜ 0.05),其中IMD+I/R组较I/R组以及空质粒+I/R组BUN和Scr水平显著降低(均P＜ 0.05).免疫组化结果显示,假手术组IMD呈弱阳性表达,主要位于肾小管间质细胞胞质内,I/R组肾组织IMD在肾小管上皮细胞和间质表达较假手术组上调;IMD+I/R组肾组织中IMD表达较I/R组明显上调(P＜0.01).与I/R组及空质粒+I/R组相比IMD+I/R组肾组织IMD mRNA,相对含量分别增加了60.7％、66.1％,蛋白相对含量分别增加了51.4％、55.9％.此外,与I/R组相比,IMD+I/R组肾组织ET-1、TNF-α蛋白表达显著降低(ET-1:0.17±0.02比0.08±0.02;TNF-α:0.35±0.02比0.21±0.04,均P＜0.05).结论 在大鼠肾脏I/R前上调IMD表达可能通过抑制ET-1、TNF-α表达保护肾脏结构及功能.     

Ischaemic preconditioning improves microvascular perfusion and oxygenation following reperfusion injury of the intestine

BACKGROUND: Ischaemia-reperfusion (IR) injury of the intestine occurs commonly during abdominal surgery. Ischaemic preconditioning (IPC) provides a way of protecting the organ from damage inflicted by IR. This study was designed to evaluate the beneficial effect of IPC, focusing on the intestinal microcirculation and oxygenation in intestinal IR injury. METHODS: Rats were allocated to three groups. Animals in the IR and IPC groups underwent 30 min of intestinal ischaemia followed by 2 h of reperfusion. In the IPC group this was preceded by 10 min of ischaemia and 10 min of reperfusion. Animals in the third group underwent laparotomy but no vascular occlusion. Intestinal microvascular perfusion, oxygenation and portal venous blood flow (PVF) were monitored continuously. At the end of the reperfusion period, blood samples were obtained for measurement of lactate dehydrogenase (LDH) and biopsies of ileum for histological evaluation. RESULTS:: IPC improved intestinal microvascular perfusion and tissue oxygenation significantly at the end of the reperfusion period (P < 0.001). PVF improved significantly in the IPC compared with the IR group (P = 0.005). The serum LDH concentration was significantly lower in the IPC than the IR group (mean(s.e.m.) 667.1(86.8) versus 1973.8(306.5) U/l; P < 0.001) Histological examination showed that ileal mucosa was significantly less injured in the IPC group. CONCLUSIONS: This study demonstrated that IPC improves intestinal microvascular perfusion and oxygenation.     

Biliverdin protects rat livers from ischemia/reperfusion injury

OBJECTIVE: To explore putative cytoprotective functions of biliverdin during hepatic ischemia/reperfusion (I/R) injury in rat models. MATERIAL AND METHODS: Male Sprague Dawley (SD) rat livers were harvested and stored for 24 hours at 4 degrees C in University of Wisconsin (UW) solution (n=18), and then perfused with blood for 2 hours on an isolated rat liver perfusion apparatus equipped for temperature (37 degrees C), pressure (13 cm H2O), and pH (7.3) maintenance. Biliverdin was added to the blood at concentrations of 10 and 50 micromol in two groups of six animals. Portal vein blood flow, bile production, and GOT/GPT levels were assessed serially. At the conclusion of the experiment, liver samples were collected for histologic evaluation using Suzuki criteria. RESULTS: BV exerted protective effects against liver I/R injury. Adjunctive biliverdin improved portal venous blood flow (mL/min/g) from the beginning of reperfusion (1.33+/-0.17 versus 0.98+/-0.15; P<.001) and increased bile production (mL/g) as compared with the control group (3.40 versus 1.88; P<.003). I/R-induced hepatocellular damage as measured by GOT/GPT release (IU/L) was diminished in the biliverdin group (91 versus 171 and 46 versus 144, respectively; P<.0001). Improved liver function by biliverdin was accompanied by preservation of the histologic structure as assessed by Suzuki criteria (3.7+/-1.4 versus 6.8+/-0.8 in untreated controls; P<.005). CONCLUSIONS: Biliverdin attenuates the ischemia/early reperfusion injury of rat liver grafts as assessed by hemodynamics, function, enzyme analysis, and histology. This study provides the rationale for novel therapeutic approaches using biliverdin to maximize the organ donor pool through the safer use of liver transplants despite prolonged periods of cold ischemia.     

Ischemic preconditioning improves rat kidney graft function after severe ischemia/reperfusion injury

Ischemic preconditioning (IP) has been shown to ameliorate renal ischemia reperfusion injury. Using a rat kidney transplantation model we determined if IP improves graft function after prolonged cold storage. MATERIALS AND METHODS: Syngeneic rat kidneys were divided into two groups. Prior to 42 hours of cold storage in UW and transplantation, one group (n = 10) received IP (15 minutes of warm ischemia/10 minutes of reperfusion), whereas another group (n = 10) received no treatment. Early graft function and 1-week recipient survival were assessed. RESULTS: Recipient survival was not significantly different between groups [70% (IP) vs 40% (non-IP); P = .28]. IP treatment led to a quicker recovery of renal function. On PODs 3 and 6, serum creatinine levels in the IP group were significantly lower compared with the untreated group. In conclusion, one cycle of IP (15/10) accelerates recovery of renal graft function after severe ischemia reperfusion injury. This simple treatment modality may improve outcomes of renal transplants with prolonged cold storage.     

甲状腺素预处理对Pringle法诱导小鼠肝脏缺血再灌注损伤的保护作用

缺血再灌注(IR)损伤在肝脏外科很常见.采用相关缺血预处理措施诱导肝脏产生保护相关蛋白质产生可能是较理想的IR肝脏损伤的保护措施[1-3].本研究探讨了三碘甲状腺素(T3)预处理对肝脏IR损伤的作用.     

Donor preconditioning with taurine protects kidney grafts from injury after experimental transplantation

BACKGROUND: Ischemia/reperfusion injury is a major problem in clinical transplantation (Tx). Taurine has been shown to protect liver grafts from ischemia/reperfusion injury after Tx. Thus, this study was designed to evaluate its effect on kidney grafts after transplantation. MATERIALS AND METHODS: Various concentrations of taurine were infused before donor nephrectomy (1.5 mL; 30, 100, 300 mM). Controls were given the same volume of Ringers' solution. Subsequently, grafts were cold-stored for 19 h in histidine-tryptophan-ketoglutarate solution and transplanted. Six hours after Tx, graft function and injury were assessed with blood urea nitrogen/creatinine and aspartate aminotransferase/lactate dehydrogenase. Graft biopsies were taken to evaluate tubular damage, caspase-3, superoxide dismutase, and heat shock protein 72 (HSP-72) to index necrosis, apoptosis, antioxidative capacity, and regeneration, respectively. RESULTS: Taurine significantly decreased blood urea nitrogen, creatinine, aspartate aminotransferase, and lactate dehydrogenase in a dose-dependent manner to up to 71%, 69%, 51%, and 53% of controls, respectively. Further, tubular damage and caspase-3 expression decreased to 44% and 18% of control values (P < 0.01), while superoxide dismutase and heat shock protein 72 expression increased by 95% and 77% of controls, respectively (P < 0.05). CONCLUSIONS: This study demonstrates that donor preconditioning with taurine protects kidney grafts from injury (apoptosis, necrosis), improves graft function, and increases the regenerative potential most likely via mechanisms including antioxidation.     

Akt activation protects rat liver from ischemia/reperfusion injury

BACKGROUND: Apoptosis as well as necrosis may play an important role in hepatic ischemia/reperfusion (I/R) injury. Akt, a serine-threonine protein kinase, is known to promote cell survival. We investigated whether gene transfer of constitutively active or dominant negative Akt could affect hepatic I/R injury. MATERIALS AND METHODS: Hepatic I/R injury was induced in rats by Pringle's maneuver for 20 min followed by reperfusion. Adenoviruses encoding a constitutively active form of Akt (myrAkt), a dominant negative form of Akt (dnAkt), or beta-galactosidase (LacZ) were injected through the tail vein 72 h before hepatic I/R. RESULTS: Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) staining demonstrated a significant increase in the positive cells 240 min after reperfusion. Immunoblotting with phospho-Akt antibody showed phosphorylation of Akt from 90 to 180 min after reperfusion. The expression of myrAkt reduced the number of TUNEL-positive cells and hepatic necrosis around the central veins in the liver after reperfusion. This expression also significantly inhibited the increase in serum alanine aminotransferase (297 +/- 131 IU/L, P < 0.05) 120 min after I/R, compared with increases in uninfected (1761 +/- 671 IU/L), LacZ adenovirus (1528 +/- 671 IU/L)-, and dnAkt adenovirus (1342 +/- 485 IU/L)-infected rats. MyrAkt expression phosphorylated Bad and inhibited the release of cytochrome-c after reperfusion. No difference in nuclear translocation of nuclear factor (NF)-kappaB, p65 was seen among the three groups of rats, however. CONCLUSION: Adenoviral gene transfer of myrAkt could inhibit apoptotic cell death and subsequent hepatic I/R injury in the rat, through Bad, not NF-kappaB.     

Effect of sevoflurane preconditioning on ischaemia/reperfusion injury in the rat kidney in vivo

BACKGROUND AND OBJECTIVE: Whereas the protective effect of anaesthetic and ischaemic preconditioning has been described for several organs, it is uncertain whether this mechanism is also effective in the kidney. We compared the effect of preconditioning with sevoflurane and preconditioning with short episodes of ischaemia on renal ischaemia/reperfusion injury in the rat in vivo. METHODS: Fourteen days after right-sided nephrectomy, anaesthetized male Wistar rats were randomly assigned to a sham-operated group (no arterial occlusion, n = 5) or underwent 45 min of left renal artery occlusion (control group, n = 9) followed by 3 days of reperfusion. Two further experimental groups of animals were preconditioned prior to ischaemia either by administering 1 MAC sevoflurane for 15 min followed by 10 min of washout (sevoflurane group, n = 10) or by subjecting the animals to three short episodes of renal ischaemia (ischaemia-preconditioned group, n = 8). Blood creatinine was measured during reperfusion and morphological damage was assessed by histological examination. RESULTS: Baseline creatinine values were similar in all four groups (0.7 +/- 0.2 mg dL-1; mean +/- SD) and remained unchanged in the sham-operated animals after 3 days (0.8 +/- 0.2 mg dL-1). Creatinine levels increased in the ischaemic preconditioning group (3.3 +/- 1.2 mg dL-1) and sevoflurane preconditioning group (4.0 +/- 1.1 mg dL-1) compared to the control group (1.6 +/- 0.6 mg dL-1). Morphological damage was less severe in the control group, i.e. in animals without preconditioning, than in both preconditioning groups. CONCLUSION: Neither sevoflurane nor ischaemic preconditioning preserves renal function or attenuates cell damage in the rat in vivo.     

Danshen protects kidney grafts from ischemia/reperfusion injury after experimental transplantation

Danshen (DS) is used for treatment of various ischemic events in the traditional Chinese medicine. Hence, this study was designed to investigate its effect on ischemia/reperfusion injury (IRI) after experimental kidney transplantation (eKTx). Nephrectomized Sprague–Dawley rats underwent eKTx. Some animals were infused with 1.5 ml DS 10 min before surgery. Kidney grafts were transplanted after cold storage for 20 h in Histidine–Tryptophane–Ketoglutarate solution. After reperfusion blood samples were collected for blood urinary nitrogen (BUN), creatinine, lactate dehydrogenase (LDH), and alanine transaminase. Further, tissue was assessed for morphologic and pathophysiologic changes. Donor preconditioning with DS (DS-d) significantly decreased BUN, creatinine, LDH, and aspartate aminotransferase to 65–97% of controls while preconditioning of the recipient (DS-r) decreased values to 58–82% ( P  < 0.05). Tubular damage and caspase-3 decreased significantly in both DS-d and DS-r (DS-d: 96% and 67%, DS-r: 83% and 75% of controls) while heat shock protein 72 and superoxide dismutase increased significantly (DS-d: 143% and 173%, DS-r: 166% and 194% of controls). Further, inducible nitric oxide synthase and tumor necrosis factor-α decreased (DS-d: 84% and 61%, DS-r: 79% and 67% of controls) after DS. Preconditioning of both donors and recipients with DS significantly reduces IRI and thus improves graft function after eKTx.     

Ischaemic preconditioning of skeletal muscle. 1. Protection against the structural changes induced by ischaemia/reperfusion injury

Ischaemic preconditioning is a process by which exposure of a tissue to a short period of non-damaging ischaemic stress leads to resistance to the deleterious effects of a subsequent prolonged ischaemic stress. It has been extensively described in the heart, but few studies have examined the possibility that it can occur in skeletal muscle. We have used a rat model of ischaemia of one limb to examine this possibility. Exposure of the hind limb to a period of ischaemia of five minutes and reperfusion for five minutes significantly protected the tibialis anterior muscle against the structural damage induced by a subsequent period of limb ischaemia for four hours and reperfusion for one hour. This protection was evident on examination of the muscle by both light and electron microscopy. Longer or shorter times of prior ischaemia had no effect.     

肠远程缺血预处理在心肌缺血/再灌注损伤中的研究进展

<正>近年来,利用机体自身抗损伤机制和耐受性从而提高机体自身保护能力的观点日益受到人们关注。自1986年Murry等[1]提出心肌缺血预     

Donor preconditioning with rabbit anti-rat thymocyte immunoglobulin ameliorates ischemia reperfusion injury in rat kidney transplantation

A major concern in transplantation is the preservation of organ function. Ischemia time and microcirculatory disturbance of the organ cannot be avoided and may result in ischemia reperfusion injury (IRI), increasing the risk of delayed graft function (DGF) and acute and chronic rejection. Anti-thymocyte immunoglobulin (rATG) is a polyclonal antibody preparation with multiple effects when administered to recipients. Our objective has been to evaluate whether the administration of rATG to kidney donors instead of recipients, in an experimental model of syngeneic rat transplantation, ameliorates IRI and facilitates immediate graft function recovery. Urea and creatinine levels and necrosis severity scores were significantly lower in kidneys from donors that had received rATG (urea: control: 211±8mg/dl vs. treatment: 110±15mg/dl, p<0.001; creatinine: control: 4.6±0.24mg/dl vs. treatment: 2.6±0.22mg/dl, p<0.001; necrosis severity scores: control: 2.3 vs. treatment: 1.6, p<0.05). TUNEL staining showed 80±13 positive cells in control group and 9±3 (p<0.001) in treatment group. In situ expression of proinflammatory cytokines TNF-α, IL-6, IL-21 and TGF-β1 was reduced in rATG group (p<0.01); the same was observed for KIM-1 and caspase 8 (p<0.001). Cytoprotective genes Bcl2 and HO-1 were upregulated in situ in treatment group (p<0.001). In situ expression of IL-17, caspase 9, IL-23a, CxCl3 and ICAM1 showed no difference between groups (p>0.05). Findings suggest ATG administered to donors may ameliorate the IRI process in kidney transplantation, expressed by lower necrosis and apoptosis scores and the improvement of renal function, which may be explained through the diminished in situ expression of inflammatory mediators.     

Pharmacological preconditioning with low-dose cyclosporine or FK506 reduces subsequent ischemia/reperfusion injury in rat kidney.

BACKGROUND: Ischemia/reperfusion (I/R) injury in the early posttransplant period is closely associated with delayed recovery of graft function, increased acute rejection, and late allograft dysfunction. Pharmacological preconditioning with low-dose cyclosporine (CsA) or FK506 was performed to induce ischemic tolerance in rat kidney with I/R injury. METHODS: Low-dose CsA (3 mg/kg, administered i.v.) or FK506 (0.3 mg/kg i.v.) were used to induce ischemic tolerance in Sprague-Dawley rats, and the induction of heat shock protein (hsp) 70 by CsA or FK506 was evaluated overtime. Rats were pretreated with CsA or FK506 6 hr before I/R injury when hsp70 was maximally expressed, and were killed 24 hr later. The effect of pharmacological preconditioning on subsequent I/R injury was evaluated in terms of renal function, histopathology score, assays for apoptosis (DNA fragmentation analysis, TUNEL staining, expressions of pro-apoptotic genes, and caspase activity), and the expression of inflammatory cytokine genes (interleukin-1 and tumor necrosis factor-alpha). RESULTS: Preconditioning with low-dose CsA or FK506 significantly improved renal function and renal histology, compared to rats with I/R injury. Apoptotic cell death (typical DNA laddering and increased TUNEL-positive cells) in rat kidneys with I/R injury, was decreased by pretreatment with low-dose CsA or FK506. Increased expression of pro-apoptotic genes (Fas, Fas-ligand, caspase 1 and 3) and activated caspases in ischemic rat kidneys were decreased after CsA or FK506 pretreatment. CONCLUSIONS: Pretreatment with low-dose CsA or FK506 prevents subsequent I/R injury, and this effect may be related to the induction of hsp70. Pretreatment of renal donors with low-dose CsA or FK506 may result in an improvement in immediate posttransplant function.     

Exogenous nitric oxide protects kidney from ischemia/reperfusion.

Blockade of NO production is followed by an increase in leukocyte rolling and adhesion resulting in some deleterious effects of ischemia. Preischemic administration of NO protects vascular integrity after reperfusion. Exogenous NO causes a direct reduction in leukocyte adhesion. This work was performed to test the hypothesis that exogenous NO administered during the preischemic period to the kidney alone, without coming into contact with the leukocytes, could also reduce leukocyte-endothelium adhesion. Adult rats were subjected to in situ isolation of the left kidney. Solutions were infused through the renal artery and drained through an incision in the renal vein, thus avoiding the systemic circulation. Group IC rats served as an ischemic control, and received 0.9% saline. Group NP received Na nitroprusside. Group S was a nonischemic control. Groups IC and NP were subjected to 75 min of renal ischemia. After this period, vascular structures were repaired and reperfusion allowed. A right nephrectomy was performed. Serum urea and creatinine, myeloperoxidase activity, and histopathological studies were carried out at different intervals after reperfusion. Survival at 15 days was 46%, 80%, and 100% in groups IC, NP, and S, respectively. Differences between groups for serum urea and creatinine were significant only during the first seven days. Myeloperoxidase values were significantly higher in group IC. All rats from group IC and only 20% from group NP showed histological evidence of necrosis. Thus, exogenous NO is protective and acts selectively upon the kidney, modulating its interactions with polymorphonuclear cells after ischemia/reperfusion.     

Remifentanil preconditioning protects against ischemic injury in the intact rat heart

BACKGROUND: Opioid receptors mediate cardiac ischemic preconditioning. Remifentanil is a new, potent ultra-short-acting phenylpiperidine opioid used in high doses for anesthesia. The authors hypothesize that pretreatment with this drug confers cardioprotection. METHODS: Male Sprague-Dawley rats were anesthetized and the chest was opened. All animals were subjected to 30 min of occlusion of the left coronary artery and 2 h of reperfusion. Before the 30-min occlusion, rats received either preconditioning by ischemia (ischemic preconditioning, 5-min occlusion, 5-min reperfusion x 3) or pretreatment with remifentanil, performed with the same regime (3 x 5-min infusions) using 0.2, 0.6, 2, 6, or 20 microg.kg.min intravenously. The experiment was repeated with naltrindole (a selective Delta-opioid receptor antagonist, 5 mg/kg), norbinaltorphimine (a selective kappa-OR antagonist, 5 mg/kg), or CTOP (a selective mu-opioid receptor antagonist, 1 mg/kg) administered before remifentanil-induced preconditioning or ischemic preconditioning, respectively. Infarct size, as a percentage of the area at risk, was determined by 2,3,5-triphenyltetrazolium staining. RESULTS: There was a dose-related reduction in infarct size/area at risk after treatment with remifentanil that was similar to that seen with ischemic preconditioning. This effect was prevented or significantly attenuated by coadministration of a mu, kappa, or Delta-opioid antagonist. The infarct-sparing effect of ischemic preconditioning was abolished by blockade of kappa-opioid receptors or Delta-opioid receptors but not by mu-opioid receptors. CONCLUSION: Remifentanil mimics cardioprotection via all three opioid receptors. This differs from ischemic preconditioning, which confers cardioprotection via kappa- and Delta-, but not mu-opioid receptors. Part of the protective effect of remifentanil may be produced by mu-agonist activity outside the heart.