Pre- or post-treatment with hepatocyte growth factor prevents glycerol-induced acute renal failure

Hepatocyte growth factor (HGF) is known to have beneficial effects against damage in various organs, including liver, kidney and lung, in disease models. Previously, we reported that repeated administration of HGF ameliorates renal dysfunction and histological alteration of glycerol-injected rats, an animal model for severe acute renal failure (ARF). In the present study, we investigated in more detail the efficacy of pre- and post-treatment of HGF in this model. ARF was induced by intramuscular injection of glycerol into the hind limbs of male Wistar rats. The efficacy of pre-treatment was studied by intravenous injection of HGF (1 mg/kg) or vehicle 1 and 18 hours prior to glycerol injection. Pre-treatment of HGF dramatically protected glycerol-induced ARF rats against death, and prevented deterioration of biochemical parameters for renal function. We also analyzed expression of heme oxygenase-1 (HO-1), a cytoprotective protein, in kidney of HGF-injected rats. Intravenous administration of HGF enhanced renal expression of HO-1 mRNA from 1 to 3 hours after injection. Next, as a post-treatment study, HGF (1 mg/kg/3 hours) with dopamine was infused into glycerol-induced ARF rats 7 hours after glycerol injection. Intravenous infusion of HGF after ARF onset also ameliorated renal biochemical parameters. These results indicate that pre-treatment of HGF can improve ARF, and induction of HO-1 expression in kidney may be a cause of the protective effect. In addition, post-treatment of HGF with dopamine was also effective against the establishment of ARF.     

Therapeutic angiogenesis in the ischemic canine heart induced by myocardial injection of naked complementary DNA plasmid encoding hepatocyte growth factor

OBJECTIVE: We investigated the efficacy of directly injecting a plasmid with complementary DNA encoding human hepatocyte growth factor into ischemic canine myocardium to induce angiogenesis. METHODS: Four weeks after ligation of the left anterior descending coronary artery, 125 microg of a complementary DNA plasmid encoding the gene for either hepatocyte growth factor (n = 8) or LacZ (transfection control group, n = 8) was injected directly into the myocardium at the border between the normal tissue and the infarction. Eight other dogs were used as a sham control group. Regional thickening fraction, which indicated contractile function, and blood flow in the normal (circumflex branch territory) and ischemic areas were evaluated under dobutamine administration just before and 4 weeks after transfection. The animals were killed, and capillary numbers in both areas were assessed. These data in the ischemic area were evaluated as the percentage of those in the normal. RESULTS: The number of myocardial capillaries in the ischemic area was successfully increased to approximately 140% of usual in the hepatocyte growth factor group, whereas no change was observed in the other groups (P =.0017 by analysis of variance). Furthermore, regional thickening fraction and blood flow in the ischemic area, which had deteriorated after coronary ligation, showed significant improvement in the hepatocyte growth factor group relative to the other groups (thickening fraction P <.0001 by analysis of variance, blood flow P =.0005 by analysis of variance). CONCLUSIONS: These results support the efficacy of the direct injection of plasmid complementary DNA encoding human hepatocyte growth factor to induce therapeutic angiogenesis in the ischemic myocardium.     

Production and activation of hepatocyte growth factor in acute renal failure

Hepatocyte growth factor (HGF) facilitates the regeneration of injured kidney in acute renal failure (ARF). HGF is produced as a single-chain precursor by cells of mesenchymal origin and is converted to a biologically active, heterodimeric molecule by proteolytic processing. We studied HGF mRNA and protein levels in systemic organs of glycerol-induced ARF rats, a model of crush syndrome. HGF protein concentration of tissue homogenate was measured by ELISA. Both mRNA and protein levels were increased in liver and spleen at 24 hours after the glycerol injection whereas HGF protein level was decreased in the injured kidney. Expression of HGF receptor/c-met mRNA was elevated only in the kidney. These results suggest that HGF supplied in an endocrine manner may play an important role in the regenerating process following ARF. Next, we measured serum HGF concentration by ELISA in 8 ARF patients caused by crush syndrome and the molecular size of serum HGF was determined by immunoblotting. Although serum HGF levels elevated in all patients, the HGF levels did not associate with their prognoses. While a single-chain molecule was predominantly observed in sera from chronic renal failure patients and healthy subjects, the majority of serum HGF was a heterodimeric form in 7 ARF patients. In one patient who developed disseminated intravascular coagulation syndrome and had a poor prognosis, a single-chain molecule was predominant although the serum HGF concentration was equivalent. These data suggest that the activity of proteolytic processing may be also an important factor for the expression of the biological function of HGF.     

Intravenous administration of hepatocyte growth factor gene ameliorates diabetic nephropathy in mice

Diabetic nephropathy is characterized by progressive loss of renal function, persistent proteinuria, and relentless accumulation of extracellular matrix leading to glomerulosclerosis and interstitial fibrosis. This study investigated the potential effects of long-term expression of exogenous hepatocyte growth factor (HGF) on normal and diabetic kidneys. Intravenous injection of human HGF gene via naked plasmid vector resulted in abundant HGF protein specifically localized in renal glomeruli, despite an extremely low level of transgene mRNA in the kidney. In uninephrectomized mice made diabetic with streptozotocin, delivery of exogenous HGF gene ameliorated the progression of diabetic nephropathy. HGF attenuated urine albumin and total protein excretion in diabetic mice. Exogenous HGF also mitigated glomerular mesangial expansion, reduced fibronectin and type I collagen deposition, and prevented interstitial myofibroblast activation. In addition, HGF prevented kidney cells from apoptotic death in the glomeruli and tubulointerstitium. Moreover, expression of HGF inhibited renal expression of TGF-beta1 and reduced urine level of TGF-beta1 protein. Therefore, despite the effects of HGF on diabetic nephropathy being controversial, these observations suggest that supplementation of HGF is beneficial in ameliorating diabetic renal insufficiency in mice.     

Ameliorative effect of hepatocyte growth factor on glycerol-induced acute renal failure with acute tubular necrosis

BACKGROUND/AIMS: Hepatocyte growth factor (HGF), a multi-potent growth factor, is known to promote regeneration of damaged renal epithelial cells. Glycerol injection into rats induces severe acute renal failure (ARF) with ischemia and tubular necrosis, a model which shares many features with human ARF or rhabdomyolysis. We investigated the efficacy of HGF in this glycerol-induced ARF rat model. METHODS: ARF was induced by intramuscular injection of glycerol into the hind limbs of male Wistar rats. HGF (0.25 mg/kg/shot) or vehicle was administered intravenously 1 h before and 1, 3, 5, 8, 24 and 36 h after glycerol injection. Biochemical parameters for serum and urine were measured and histological analyses of the kidneys were performed. We also analyzed endogenous HGF expression and phosphorylation of c-Met/HGF receptor in the kidneys of glycerol-induced ARF rats. RESULTS: Glycerol treatment caused severe ARF which invariably led to death of the rats. Repeated administration of HGF protected rats from death caused by severe ARF. Histological analyses revealed that HGF treatment reduced necrosis of tubular cells in the renal cortex. Serum/urine biochemical parameters also showed that renal dysfunction was improved by HGF administration. Intravenous administration of HGF enhanced phosphorylation of the c-Met/HGF receptor and mitogen-activated protein kinase in the kidney. In the vehicle-treated group the renal endogenous HGF concentration decreased and there was no change in c-Met/HGF receptor phosphorylation. CONCLUSION: These results indicate that HGF effectively accelerated the recovery of renal function and improved survival in glycerol-induced ARF rats.     

观察重组人肝细胞生长因子裸质粒表达产物在人体血液中的含量及其抗原性变化

目的 研究血浆中重组人肝细胞生长因子裸质粒(pCK-HGFX7)表达产物肝细胞生长因子(hepatocyte growth factor,HGF)含量在体内的变化,以及应用本品后是否发生免疫反应产生HGF抗体.方法 选择21例严重下肢缺血性疾病患者(Rutherford分级4～6级),随机分为4mg、8mg、12mg、16mg 4个剂量组.将每组剂量等量平分后在试验期第1天及第15天于下肢缺血部位的供血动脉走行和侧支循环可能建立的部位肌内注射给药.采集第1(第1次给药前)、8、15(第2次给药前)、21、59天血浆样本测定HGF含量;采集第1、15、28、59、91天血浆样本测定HGF抗体含量.结果 (1)局部肌内注射给药后受试者血浆中HGF含量范围为216～1189.75 pg/mL;(2)未检测到受试者血浆中存在HGF抗体,提示外周血中未见HGF抗体生成.结论 重组人肝细胞生长因子裸质粒局部肌内注射后,其表达产物HGF在外周血中含量未见明显异常波动,应用本品后人体没有发生免疫反应.     

Recipient intramuscular cotransfection of naked plasmid transforming growth factor beta1 and interleukin 10 ameliorates lung graft ischemia-reperfusion injury

OBJECTIVE: Multiple gene transfer might permit modulation of concurrent biochemical pathways involved in lung graft ischemia-reperfusion injury. In this study we analyzed whether recipient intramuscular naked plasmid cotransfection of transforming growth factor beta(1) and interleukin 10 would result in amelioration of lung graft ischemia-reperfusion injury. METHODS: Forty-eight hours before transplantation, 6 groups (n = 6) of F344 rats received intramuscular injection of naked plasmid encoding chloramphenicol acetyltransferase, chloramphenicol acetyltransferase plus beta-galactosidase, transforming growth factor beta(1), interleukin 10, or transforming growth factor beta(1) plus interleukin 10 or were not treated. Donor lungs were flushed and stored for 18 hours at 4 degrees C before transplantation. Twenty-four hours later, grafts were assessed immediately before the animals were killed. Arterial oxygenation, wet/dry ratio, myeloperoxidase, and proinflammatory cytokines (interleukin 1, tumor necrosis factor alpha, interferon gamma, and interleukin 2) were measured, and immunohistochemistry was performed. RESULTS: For lung graft function, the arterial oxygenation was considerably higher in the cotransfected group receiving transforming growth factor beta(1) plus interleukin 10 compared with that in all other groups (P < or =.03). The wet/dry ratio, reflecting lung edema, was reduced in the cotransfected group compared with that in control animals (nontreated, P <.02; chloramphenicol acetyltransferase, P <.03; chloramphenicol acetyltransferase plus beta-galactosidase, P <.01). Myeloperoxidase, which measures neutrophil sequestration, was also reduced with cotransfection compared with that seen in control animals (P < or =.03). All proinflammatory cytokines were decreased in the cotransfected group compared with those in all other groups (interleukin 1beta, P <.04; tumor necrosis factor alpha, P <.002; interferon gamma, P <.0001; interleukin 2, P <.03). These results indicate that cotransfection provides a synergistic benefit in graft function versus either cytokine alone, neutrophil sequestration, or inflammatory cytokine expression. Immunohistochemistry showed positive staining of transforming growth factor beta(1) plus interleukin 10 in type I and II pneumocytes and localized edema fluid. CONCLUSIONS: Recipient intramuscular naked plasmid cotransfection of transforming growth factor beta(1) and interleukin 10 provides a synergistic effect in ameliorating lung reperfusion injury after prolonged ischemia.     

Cause of death in acute renal failure.

The cause of 636 deaths during acute renal failure (ARF) occurring between 1956 and 1989 were analysed. Deaths due to haemorrhage and to non-recovery of renal function have declined but cardiovascular deaths and withdrawal of active treatment have increased. The causes of death varied with the clinical situation in which ARF arose. The most important factor contributing to death was the underlying cause of ARF. 67% deaths due to sepsis resulted from infection present at the time of development of ARF. Deaths due to secondary complications have declined, indicating that the precipitating causes of ARF are the main determinant of overall mortality.     

Blockage of tubular epithelial to myofibroblast transition by hepatocyte growth factor prevents renal interstitial fibrosis.

Activation of alpha-smooth muscle actin-positive myofibroblast cells is a key event in the progression of chronic renal diseases that leads to end-stage renal failure. Although the origin of these myofibroblasts in the kidney remains uncertain, emerging evidence suggests that renal myofibroblasts may derive from tubular epithelial cells by a process of epithelial to mesenchymal transition. It was demonstrated that hepatocyte growth factor (HGF) exhibited a remarkable ability to block this phenotypic transition both in vitro and in vivo. HGF abrogated the alpha-smooth muscle actin expression and E-cadherin depression triggered by transforming growth factor-beta1 in tubular epithelial cells in a dose-dependent manner. HGF also blocked morphologic transformation of tubular epithelial cells and inhibited the expression and extracellular deposition of fibronectin. In a mouse model of renal fibrosis disease induced by unilateral ureteral obstruction, transforming growth factor-beta type I receptor expression was specifically increased in renal tubules, and myofibroblastically phenotypic transition of the tubules was evident in vivo. Remarkably, injections of exogenous HGF blocked myofibroblast activation and drastically prevented renal interstitial fibrosis in the obstructed kidneys. These results suggest that tubular epithelial to myofibroblast conversion may play an important role in the pathogenesis of renal fibrosis and that blocking this phenotypic transition could provide a novel therapeutic strategy for the treatment of fibrotic diseases.     

肝细胞生长因子对实验性急性胰腺炎细胞凋亡作用的研究

目的:观察外源性肝细胞生长因子(HGF)对小鼠轻症实验性急性胰腺炎的炎症反应及胰腺细胞凋亡的作用。方法:以雨蛙肽腹腔注射诱发小鼠轻症实验性急性胰腺炎。第1组以盐水腹腔注射作为对照,第2、3及4组每小时腹腔注射雨蛙肽诱发急性胰腺炎;第3组在造模前及造模中两次皮下注射重组人肝细胞生长因子(rhHGF);第4组同时皮下注射rhHGF及其单抗。观察HGF对炎症反应的干预作用及对腺泡细胞凋亡的影响。结果:炎症小鼠予每公斤体重4、20μgrhHGF时,与单纯炎症组相比,血清淀粉酶、脂肪酶下降,胰腺组织学炎症评分减少,胰腺腺泡细胞TUNEL凋亡指数增加,caspase3活性增强。予每公斤体重4或20μgrhHGF时,其效应无显著性差异。同时予rhHGF单抗的小鼠,上述指标与单纯炎症组相比差异无显著性。结论:HGF能减轻雨蛙肽诱导的小鼠轻症实验性急性胰腺炎。HGF单抗能消除HGF的生物学作用。HGF可以促进急性胰腺炎时腺泡细胞的凋亡,这可能是其保护胰腺的作用机制之一。     

Reciprocal balance of hepatocyte growth factor and transforming growth factor-beta 1 in renal fibrosis in mice

BACKGROUND: Transforming growth factor-beta 1 (TGF-beta 1) plays a central role in the pathogenesis of renal fibrosis. In contrast, hepatocyte growth factor (HGF) may be an important molecule for tissue repair. As TGF-beta 1 is a suppressor molecule for HGF expression, we asked whether a decrease in HGF expression would be accompanied by an increase in TGF-beta 1 and whether the progression of renal fibrosis would be modulated. METHODS: We used the ICR strain-derived glomerulonephritis (ICGN) mice as a model of chronic renal disease and examined changes in local HGF expression during the natural course of renal fibrosis. To determine the significance of intrinsic HGF noted during progression of renal fibrosis, we administered an anti-HGF antibody to mice at the early stage of renal fibrosis. RESULTS: At an early stage of renal fibrosis, the mice showed strong peritubular HGF expression, coinciding with tubular proliferation. In the late stages, the renal HGF level was markedly decreased, coinciding with a reduction in proliferative tubular areas. Renal TGF-beta 1 levels were increased in accordance with expansion of fibrotic areas. Notably, the anti-HGF antibody treatment of early-stage mice decreased the HGF level and reduced tubular areas, whereas collagen-deposited areas were expanded in parallel with increased TGF-beta 1 levels. Consequently, in HGF-neutralized mice, there was a rapid progression of renal dysfunction. CONCLUSIONS: Not only an increase in TGF-beta 1 level, but also a decrease in local HGF expression may be responsible for the manifestation of renal fibrosis, particularly tubular destruction.     

Epidermal growth factor potentiates renal cell death in hydronephrotic neonatal mice, but cell survival in rats

BACKGROUND: Epidermal growth factor (EGF) markedly attenuates tubular apoptosis induced by unilateral ureteral obstruction (UUO) in the neonatal rat, and reduces apoptosis induced by mechanical stretch of cultured rat tubular cells. METHODS: To investigate the role of EGF in modulating apoptosis resulting from UUO, neonatal wild type and mutant mice lacking EGF (knockout), or with diminished EGF receptor activity (waved-2 mutant) were compared to control mice for tubular apoptosis and atrophy. Rat and mouse kidneys were compared for localization of the EGF receptor. Apoptosis was also measured in cultured mouse tubular cells subjected to stretch and exposed to EGF. RESULTS: UUO reduced endogenous renal EGF expression in wild-type mice. Unlike the rat, exogenous EGF did not decrease tubular apoptosis or atrophy in the obstructed kidney, and significantly increased stretch-induced apoptosis of cultured mouse tubular cells. Tubular apoptosis was 50% lower in the obstructed kidney of EGF knockout and waved-2 mice relative to wild type and heterozygous animals. Exogenous EGF increased tubular apoptosis and doubled atrophy in the obstructed kidney of waved-2 mice. Species differences in EGF receptor localization were detected in 3-day-old kidneys. CONCLUSION: EGF acts as a survival factor in the neonatal rat, but potentiates tubular cell death in the neonatal mouse. Species differences are maintained in cultured cells, suggesting that differences in EGF receptor signaling underlie these opposing effects.     

Serum hepatocyte growth factor concentration in patients with various degrees of chronic renal failure

Summary: Serum hepatocyte growth factor (HGF) concentrations were measured in healthy volunteers, chronic renal failure patients without renal replacement therapy and haemodialysis patients. Serum HGF concentrations in healthy volunteers, chronic renal failure patients and haemodialysis patients were 0.18 ± 0.04 (s.d.), 0.28 ± 0.06 and 0.46 ± 0.22 ng/mL, respectively. Serum HGF concentration in chronic renal failure patients was significantly higher than that in healthy volunteers. Serum HGF concentration in haemodialysis patients was significantly higher than those in healthy volunteers and chronic renal failure patients. There was no regression of serum HGF concentration on age, sex, history of haemodialysis, prehaemodialysis serum creatinine concentration, and serum tumour necrosis factor (TNF)-α concentration. We conclude that chronic renal disease and haemodialysis therapy are contributing factors to an increased serum HGF concentration.     

活体转染肝细胞生长因子基因对小鼠急性肝功能衰竭的治疗作用

目的 研究肝细胞生长因子（HGF）基因治疗对小鼠急性肝衰模型的治疗作用。方法 构建人肝细胞生长因子（hHGF）表达载体，利用脂质体介导法在活体内转染肝细胞生长因子基因，利用荧光显微镜检测肝组织内绿色荧光蛋白（GFP）表达了解目的基因的表达，用酶联免疫吸附试验（ELISA）法检测血清中人肝细胞生长因子的含量，通过观察小鼠急性肝衰模型的生存率、肝功能变化、肝组织病理改变来检测肝细胞生长因子基因对急性肝衰的治疗作用，通过检测肝组织中PC—NA指数的变化了解肝脏的增殖能力的变化。结果 荧光显微镜下可见肝组织内有绿色荧光蛋白的表达，转染人肝细胞生长因子基因后在血清中可检测到hHGF的表达，而且可持续1周以上，与对照组相比。转染hHGF基因组的生存率明显提高（40．0％vs11．5％，P〈0．05），血清ALT、TBi明显降低，肝组织中PCNA指数也明显升高。结论 活体转染肝细胞生长因子基因可获得表达，而且肝细胞生长因子基因对急性肝衰小鼠有治疗作用。     

Salviae radix extract prevents cisplatin-induced acute renal failure in rabbits.

The present study was carried out to determine if salviae radix extract (SRE) exerts a beneficial effect against cisplatin-induced renal failure in rabbits. Rabbits were pretreated with SRE orally for 7 days, followed by cisplatin injection (5 mg/kg i.p.). Cisplatin injection caused a reduction in GFR, which was accompanied by an increase in serum creatinine levels. The fractional Na+ excretion was increased by cisplatin injection. PAH uptake by renal cortical slices was inhibited by the administration of cisplatin. Such changes were prevented by SRE pretreatment. Cisplatin injection increased lipid peroxidation, which was prevented by SRE pretreatment. The protective effect of SRE was supported by morphological studies. Cisplatin injection reduced renal blood flow that was not affected by SRE pretreatment. Cisplatin treatment in vitro in renal cortical slices increased LDH release and lipid peroxidation, which were prevented by 0.05% SRE. These results indicate that lipid peroxidation plays a critical role in cisplatin-induced acute renal failure. SRE exerts a protective effect against renal cell injury induced by cisplatin, and its effect may be attributed to its antioxidant action. However, the underlying mechanism by which SRE has antioxidant action remains to be defined.     

Serum hepatocyte growth factor levels in patients with renal diseases.

The serum levels of hepatocyte growth factor (HGF) were determined in patients with various renal diseases. In patients with acute-phase acute renal failure (ARF) and chronic tubulointerstitial nephritis (chronic TIN), the serum HGF levels were 0.55 +/- 0.24 and 0.44 +/- 0.37 ng/ml (mean +/- SD), respectively, and were significantly higher than that in the control group (0.12 +/- 0.12 ng/ml). The serum HGF level tended to be high also in patients with active-phase steroid-sensitive nephrotic syndrome (SSNS). The serum levels of HGF were not elevated in patients with IgA nephropathy (IgAN), Henoch-Sch?nlein purpura nephritis (HSPN), membranoproliferative glomerulonephritis (MPGN), poststreptococcal acute glomerulonephritis (PSAGN), unilateral renal atrophy, unilateral nephrectomy, or proximal tubular dysfunction. These observations suggest that glomerular disorders cause no apparent elevation of the serum HGF level, and that elevation of the serum HGF level may be associated with tubulointerstitial damage in renal diseases.     

Prevention of acute ischemic renal failure by targeted delivery of growth factors to the proximal tubule in transgenic mice: the efficacy of parathyroid hormone-related protein and hepatocyte growth factor

Treatment of acute renal failure (ARF) would be enhanced by identification of factors that accelerate renal recovery from injury. Parathyroid hormone-related protein (PTHrP) and hepatocyte growth factor (HGF) have been shown to stimulate proliferation in proximal nephron-derived cells. For studying the pathophysiologic roles and therapeutic potential of these two factors in ARF, transgenic mice overexpressing PTHrP or HGF in the proximal tubule under the direction of the gamma-glutamyl transpeptidase-I promoter were developed. These mice display (1) abundant expression of the respective transgenes in the kidney; (2) similar PTH type I receptor and HGF receptor (c-met) expression levels in the proximal tubule compared with control littermates; and (3) normal renal morphology, function, and tubule cell proliferation under basal conditions. However, in contrast to control mice, when acute ischemic renal injury was induced, renal function rapidly and dramatically recovered in HGF-overexpressing mice. In addition, 48 h after ischemia, HGF-overexpressing transgenic mice displayed a fourfold increase in tubule cell proliferation and a threefold decrease in apoptotic tubule cell death compared with control mice. In contrast, PTHrP-overexpressing mice responded to either ischemic or folic acid-induced renal damage similarly to control mice. These studies demonstrate that overexpression of PTHrP in the proximal nephron of mice does not seem to provide protection against acute renal injury. In marked contrast, HGF overexpression results in dramatic protection from ischemia-induced ARF, without inducing any apparent alteration in the physiology of the kidney under normal conditions. These studies suggest that HGF, when targeted specifically to the proximal tubule, may have therapeutic potential in providing protection against ischemia-induced renal failure.     

Time course of growth factor expression in mercuric chloride acute renal failure

BACKGROUND.: Renal EGF expression decreases in varying models of acute renalfailure (ARF). We found previously that the loss of distal tubularEGF during gentamicin ARF is strongest in the cortex, whereproximal tubular injury was most severe. To gain more insightinto the mechanism underlying this apparent anatomical association,renal growth factor expression was investigated during mercuricchloride ARF, in which proximal tubular injury is most severein the outer stripe of the outer medulla (OSOM). METHODS.: Endogenous renal growth factor expression was investigated byRNA hybridization and by imrnunohistochemistry in a rat modelof mercuric chloride ARF. In addition we determined temporaland spatial profiles of tubular injury, cell proliferation,and mononuclear cell infiltration during the 3-week observationperiod. RESULTS.: Serum creatinine values were maximal 2 days after treatmentand were again normalized at day 6. Tubular injury was mostsevere in the PST and maximal at day 2. Cell proliferation wasalso highest in the PST and maximal at day 4. Three weeks aftertreatment, normal renal morphology was restored. Increased numbersof mononuclear cells appeared transiently in the renal interstitiumfrom day 1 on. Most of these cells were macrophages and T lymphocytes;macrophages surrounded preferentially the severely injured PSTin the OSOM. In analogy to gentamicin ARF, renal EGF and IGF-Igene expression were decreased early in the setting of mercuricchloride ARF. The decrease in distal tubular EGF staining wasmost pronounced in the OSOM, i.e. the anatomical area wheremercuric-chloride-induced proximal tubular injury was most severe. CONCLUSIONS.: Renal EGF and IGF-I gene expression decreases strongly duringmercuric chloride ARF. The spatial association between the initialdecrease of distal tubular EGF expression and the zone of majorproximal tubular injury could originate from metabolic alterationssecondary to oxygen starvation. A possible role of mononuclearcells remains to be determined.     

Glycine attenuates apoptotic cell death in uranyl acetate-induced acute renal failure in rats

Background. Although uranyl acetate (UA) is known to induce apoptosis in renal tubular cells, the pathophysiological role of apoptotic cell death in UA-induced acute renal failure (ARF) is not clear. In this study, we examined whether glycine, which is known to provide protection against nephrotoxic acute renal failure, attenuated tubular damage in UA-induced ARF in rats, and, if so, whether the attenuation of tubular damage was associated with reduced apoptotic cell death. Methods. Sprague-Dawley rats were allocated to three groups; normal controls, UA-treated, and UA plus glycine-treated. Acute renal failure was induced by the intravenous injection of UA (5 mg/kg). UA plus glycine-treated rats were given glycine at 1 g/kg, i.v. over 3 min at the same time as the UA injection. Serum creatinine concentration (Scr) and tubular damage score were examined 5 days after UA administration. Apoptosis was evaluated by counting the number of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells in the outer stripe of the outer medulla. Results. Glycine significantly decreased the UA-induced increases in Scr (3.73 ± 0.31 vs 2.74 ± 0.11 mg/dl; P < 0.05) and the tubular damage score (3.83 ± 0.13 vs 2.58 ± 0.01; P < 0.01). UA significantly increased the number of TUNEL-positive cells in the outer stripe of the outer medulla (0.16 ± 0.04 vs 7.45 ± 0.46/high power field at ×400 magnification; P < 0.01 vs normal control value). Glycine infusion significantly lessened the number of TUNEL-positive cells (5.84 ± 0.31/ high power field at ×400 magnification; P < 0.01 vs UA-treated rats). A significant correlation was found between the number of TUNEL-positive cells and the tubular damage score (r = 0.93; P < 0.01). Conclusion. Glycine ameliorated the severity of UA-induced ARF and the degree of apoptotic cell death. This finding suggested that the protective effect of glycine in UA-induced ARF may be mediated, at least in part, through a reduction of apoptosis. Received: January 22, 1999 / Accepted: July 7, 1999