The role of autophagy in unilateral ureteral obstruction rat model

Aim: Autophagy is a cellular process of degradation of damaged cytoplasmic components and regulates cell death or proliferation. Unilateral ureteral obstruction (UUO) is a model of progressive renal fibrosis in the obstructed kidney. And UUO is followed by compensatory cellular proliferation in the contralateral kidney. We investigate the role of autophagy in the obstructed kidney and contralateral kidney after UUO. Methods: To obtain the evidence and the patterns of autophagy during UUO, the rats were sacrificed 3, 7 and 14 days after UUO. To examine the efficacy of the autophagy inhibitors, 3‐methyladenine (3‐MA), the rats were treated daily with intraperitoneal injection of 3‐MA (30 mg/kg per day) for 7 days. Results: After UUO, autophagy was induced in the obstructed kidney in a time‐dependent manner. Inhibition of autophagy by 3‐MA enhanced tubular cell apoptosis and tubulointerstitial fibrosis in the obstructed kidney after UUO. In the contralateral kidney, autophagy was also induced and prolonged during UUO. Inhibition of autophagy by 3‐MA increased the protein expression of proliferating cell nuclear antigen significantly in the contralateral kidney after UUO. The Akt‐mammalian target of rapamycin (mTOR) signalling pathway was involved in the induction of autophagy after UUO in both kidneys. Conclusion: Our present results support that autophagy induced by UUO has a renoprotective role in the obstructed kidney and regulatory role of compensatory cellular proliferation in the contralateral kidney through Akt‐mTOR signalling pathway.     

Regulation of aquaporins and sodium transporter proteins in the solitary kidney in response to partial ureteral obstruction in neonatal rats

Unilateral ureteral obstruction (UUO) impairs function of the obstructed kidney, and the contralateral nonobstructed kidney compensates depending on the degree and duration of UUO. This study aimed to determine the hemodynamic and molecular changes in the solitary kidney in response to partial ureteral obstruction (PUO) where any compensation from the contralateral kidney was eliminated so that all observed changes in the kidney tissue occurred in the kidney with PUO. Newborn rats were subjected to unilateral left nephrectomy (UNX) within the first 48 h of life and a subset of UNX rats was subjected to severe PUO of the right kidney at day 14. Renal blood flow and whole kidney volume were measured with MRI at week 10. The renal protein abundance of aquaporin 1 (AQP1), AQP2 and AQP3 as well as Na,K-ATPase, NaPi-2 (type 2 sodium-phosphate cotransporter) and NHE3 (type 3 sodium-proton exchanger) were examined by immunoblotting and immunocytochemistry. At 10 weeks of age, the protein abundance of AQP2, AQP3, Na,K-ATPase, NaPi-2 and NHE3 were increased in response to PUO. In contrast, AQP1 expression was markedly decreased compared to sham-operated rats. These findings were confirmed by immunohistochemistry. GFR, urine osmolality and urine sodium excretion were reduced and kidney weight increased in response to PUO. In conclusion, the present study demonstrated major changes in the protein abundance of renal AQP1, AQP2 and AQP3 and sodium transporters in the solitary PUO kidney. These changes were paralleled by decreased urinary sodium excretion and a significant reduction in urinary osmolality from the obstructed kidney, suggesting a functional association between the molecular changes and the ability of the obstructed kidney to handle sodium and water in this solitary kidney model.     

骨调素和单核细胞趋化蛋白在大鼠梗阻性肾病中的表达及可能作用

目的:探讨骨调素(OPN)和单核细胞趋化蛋白(MCP-1)在大鼠梗阻性模型中的表达及其在肾脏纤维化发病机制中的作用.方法:采用-单侧输尿管结扎制造梗阻性肾病模型,分别于造模后7 d、14 d取肾组织,应用HE染色观察肾脏病理改变,免疫组化方法检测肾组织畔OPN和MCP-1蛋白的表达,应用逆转录-聚合酶链式反应(RT-PCR)法观察肾组织中OPN mRNA和MCP-1 mRNA的变化.结果:OPN、MCP-1表达主要位于肾小管上皮细胞,随着梗阻时间的延长,肾组织中OPN、MCP-1蛋白和mRNA表达明显增加.结论:OPN、MCP-1蛋白和mRNA在梗阻性肾病大鼠肾组织表达明显增加介导炎症过程,参与肾间质纤维化.     

The expression of mRNA for tumour necrosis factor-α increases in the obstructed kidney of rats soon after unilateral ureteral ligation

Summary: Cytokines, including transforming growth factor (TGF)-β1, contribute to the tubulointerstitial fibrosis of ureteral obstruction. Tumour necrosis factor (TNF)-α, a proinflammatory cytokine produced by multiple cells including macrophages and resident renal cells, has a role in inflammatory cell recruitment in glomerular injury. We measured TNF-α mRNA in the renal cortex of rats at different times after the onset of unilateral ureteral obstruction (UUO) and determined whether angiotensin II (AngII) inhibition or total body irradiation affects the mRNA levels of TNF-α. Rats were killed at 1, 2, 4, 24, 72 and 120h after UUO. Levels of TNF-α mRNA increased significantly in the obstructed kidney at 1h (X 2), 2h (X 2.7), 4h (X 3.6), 24h (X 2.7), 72h (X 1.8) and 120h (X 2.8) after ureteral ligation when compared to the contralateral kidney of the same animals or to control (normal) kidneys. Tumour necrosis factor-α mRNA increased in renal cortical tubules but not in glomeruli. Treatment with enalapril, an angiotensin-converting enzyme (ACE) inhibitor, before and after UUO decreased TNF-α mRNA levels in the obstructed kidney by about 40% at 4h after the onset of UUO, but at 120h there was no difference in TNF-α levels in the obstructed kidney of treated and untreated animals. Total body irradiation, which depletes macrophages in the obstructed kidney, did not prevent the upregulation of TNF-α mRNA expression at 4 h after UUO. Thus, TNF-α may have a role in initiating tubulointerstitial injury in the obstructed kidney. Leucocytes infiltrating the renal interstitium of the obstructed kidney do not appear to contribute to the increased mRNA expression of TNF-α. Angiotensin II may contribute, at least in part, to the early increased expression of TNF-α mRNA in the obstructed kidney.     

Sulfasalazine reduces inflammatory renal injury in unilateral ureteral obstruction

The purpose of this study was to test whether sulfasalazine has a protective action against interstitial inflammation and the development of renal fibrosis in obstructive nephropathy. Female rats were subjected to a sham (n = 10) or unilateral ureteral obstruction (UUO, n = 30). UUO was induced in rats by ligating the left ureter. Three days after operation, rats subjected to UUO were randomized to receive tretment with either sulfasalazine (100 mg/kg) or vehicle every day for the last 7 days of the experiment. At 10 days following UUO, the obstructed kidney exhibited tubulointerstitial injury and leukocyte infiltration (mainly monocytes) that were associated with high levels of reactive oxygen species, cytokines, transforming growth factor (TGF)-β1, myeloperoxidase (MPO), and lipid peroxidation. Ten days after UUO, the obstructed kidney was also associated with increased nuclear factor kappa beta (NF-κβ) expression in saline-treated rats. Compared with sham-operated rats, UUO rat kidneys showed lower concentrations of antioxidant enzymes in the obstructed kidney tissue. All of these changes were significantly attenuated by treatment with sulfasalazine in the obstructed kidney. Sulfasalazine protected against the renal interstitial inflammation and tissue damage elicited by ureteral occlusion. Inhibition of the NF-κβ-dependent pathway and inflammatory response and oxidative stress inhibition is likely to be involved in the beneficial effects of sulfasalazine.     

Unilateral ureteral obstruction in early development alters renal growth: dependence on the duration of obstruction

PURPOSE: Over 90% of nephrogenesis in the rat takes place postnatally in the first 10 days, analogous to the midtrimester human fetus. We wished to determine the relationship between the duration of unilateral ureteral obstruction and growth and morphology of both kidneys following relief of the obstruction in the neonatal rat. MATERIALS AND METHODS: One ureter of 1 day-old rats was sham-operated or occluded and released 1, 2, 3, or 5 days later, or not released. Fourteen or 28 days later, renal mass, tubular atrophy, and interstitial fibrosis were determined in the obstructed and contralateral kidney of each group. RESULTS: At 28 days, there was a linear relationship between kidney/body weight ratio and duration of obstruction, such that the decrement in renal mass resulting from ipsilateral obstruction was precisely compensated by an equal increment in the mass of the contralateral kidney (both, p <0.0001). Tubular atrophy was increased 100-fold in kidneys of rats with 28 days continuous ipsilateral obstruction, while relief of obstruction after 2 to 5 days reduced tubular atrophy by 90% (p <0.01). Interstitial fibrosis was also markedly reduced by relief of obstruction, with the severity of fibrosis being proportional to the duration of obstruction. CONCLUSIONS: We conclude that ureteral obstruction during the critical period of nephrogenesis impairs growth of the obstructed kidney and stimulates growth of the contralateral kidney in direct proportion to the duration of obstruction. Moreover, counterbalance between the two kidneys is finely regulated. Even 2 days of ureteral obstruction (with subsequent relief) induces contralateral renal growth, and induces ipsilateral tubular atrophy. However, the time dependence of renal injury on duration of obstruction suggests that earlier relief of obstruction in the developing kidney may allow greater ultimate preservation of functional renal mass.     

The effect of the thromboxane A2 synthesis inhibitor OKY-046 on renal function in rabbits following release of unilateral ureteral obstruction

A marked decrease in renal blood flow (RBF) and glomerular filtration rate (GFR) was found after 24, 48 and 72 hours of total unilateral ureteral obstruction (UUO) in the rabbit. Contralateral GFR showed a modest increase consistent with compensatory hypertrophy. The urinary excretion of thromboxane B2 (TxB2), the stable metabolite of the vasoconstrictor prostaglandin, thromboxane A2 (TxA2) was significantly elevated in the urine obtained following release of the obstructed ureter when compared to the TxB2 level in the urine from the contralateral kidney. Continuous infusion of OKY-046 at 100 micrograms./kg./min. over 24 hours during UUO decreased TxB2 excretion by greater than 80 per cent. However there was no significant preservation of RBF or GFR of the obstructed kidney following ureteral release despite the selective inhibition of TxA2. Moreover the increase in contralateral GFR was also abolished. Taken together with other studies these results strongly suggest that the potent vasoconstrictor TxA2 is not responsible for the rise in renal resistance that follows acute UUO.     

Ureteral obstruction in the neonatal guinea pig: Interaction of sympathetic nerves and angiotensin

The contribution of sympathetic nerves to the hemodynamic effects of unilateral ureteral obstruction (UUO) was investigated in the neonatal guinea pig. The left ureter was partially constricted (or sham-operated) at birth, and sympathetic innervation was inhibited by guanethidine and compared with saline vehicle-treated animals. At 15–20 days of age, blood presure, cardiac output, total vascular resistance (TVR), renal blood flow, and renal vascular resistance (RVR) were determined before and after infusion of enalapril. UUO reduced cardiac output, increased TVR, and increased RVR of the ipsilateral kidney, whereas guanethidine treatment had no additional effects. Enalapril decreased RVR only in obstructed kidneys and not in intact opposite kidneys of animals with UUO. This was not affected by guanethidine administration. In contrast, enalapril decreased RVR only in guanethidine-treated (but not saline-treated) sham-operated guinea pigs. Therefore, UUO increases angiotensin-dependent vascular tone of the ipsilateral kidney independent of renal innervation. However, UUO decreases angiotensin-mediated vascular tone of the contralateral kidney, an effect unmasked by sympathectomy.     

三七总皂苷对单侧输尿管梗阻大鼠肾组织BMP-7及TGF-β1/samds信号传导通路的影响

目的:观察三七总皂苷(PNS)对单侧输尿管梗阻(UUO)大鼠肾组织骨形成蛋白-7(BMP-7)及TGF-β1/Smads信号传导通路的影响。方法:将50只雄性Wistar大鼠随机分为5组:假手术组、模型组、肾康注射液组(对照组)、PNS低剂量组(低剂量组)、PNS高剂量组(高剂量组),每组10只,除假手术组,其余各组用UUO法建立肾间质纤维化动物模型,术前1d起各组给予相应浓度和剂量的药物,术后第14天处死所有大鼠,检测大鼠血肌酐(Scr)和尿素氮(BUN)变化,梗阻侧肾组织行HE染色、PAS染色和Masson染色,观察肾组织病理变化并半定量计算肾小管损伤指数(TII),免疫组化法检测BMP-7、TGF-β1、Smad2、Smad7在肾组织的表达。结果:与模型组相比,PNS和肾康注射液能明显降低UUO大鼠术后14dScr、BUN(P<0.05);对梗阻侧肾组织HE染色、PAS染色进行TII评分发现,2个试验组大鼠肾小管损伤指数显著低于模型组(P<0.01);Masson染色观察发现,2个实验组大鼠肾小管间质病变明显轻于模型组;免疫组化法染色并对其灰度值测定发现,与模型组相比,2个试验组大鼠TGF-β1、Smad2在肾组织的表达下调(P<0.01),BMP-7、Smad7在肾脏组织的表达上调(P<0.01)。结论:PNS可能通过干预BMP-7/Smads/TGF-β1信号转导通路抑制了TGF-β1信号的细胞内转导,而起到抗肾间质纤维化的作用。     

Ureteral obstruction in the neonatal rat: Renal nerves modulate hemodynamic effects

In the neonate, chronic unilateral ureteral obstruction (UUO) reduces renal blood flow (RBF) of the ipsilateral kidney and increases RBF of the opposite kidney. To determine whether renal nerves mediate or modulate these responses complete left UUO in the neonatal rat was used as a model of severe obstructive uropathy, and was compared with sham-operated controls. At 24–28 days of age, animals underwent left or right mechanical renal denervation or left sham renal denervation. One week after denervation, animals were anesthetized and blood pressure and heart reate were measured. Cardiac output and RBF were determined by the radioactive microsphere technique. UUO increased blood pressure and heart rate, and decreased RBF in the obstructed kidney, regardless of denervation. While left UUO increased RBF to the intact opposite kidney in rats with left renal denervation, this was attenuated by right renal denervation. Thus, in the neonatal rat, UUO modulates systemic renal hemodynamics, possibly through activation of the renin-angiotensin system. While renal nerves do not mediate the vasoconstriction of the obstructed kidney, renal nerves modulate vascular tone of the kidney contralateral to UUO.     

Renal structural and functional repair in a mouse model of reversal of ureteral obstruction

The end point of immune and nonimmune renal injury typically involves glomerular and tubulointerstitial fibrosis. Although numerous studies have focused on the events that lead to renal fibrosis, less is known about the mechanisms that promote cellular repair and tissue remodeling. Described is a model of renal injury and repair after the reversal of unilateral ureteral obstruction (UUO) in male C57bl/6J mice. Male mice (20 to 25 g) underwent 10 d of UUO with or without 1, 2, 4, or 6 wk of reversal of UUO (R-UUO). UUO resulted in cortical tubular cell atrophy and tubular dilation in conjunction with an almost complete ablation of the outer medulla. This was associated with interstitial macrophage infiltration; increased hydroxyproline content; and upregulated type I, III, IV, and V collagen expression. The volume density of kidney occupied by renal tubules that exhibited a brush border was measured as an assessment of the degree of repair after R-UUO. After 6 wk of R-UUO, there was an increase in the area of kidney occupied by repaired tubules (83.7 +/- 5.9%), compared with 10 d UUO kidneys (32.6 +/- 7.3%). This coincided with reduced macrophage numbers, decreased hydroxyproline content, and reduced collagen accumulation and interstitial matrix expansion, compared with obstructed kidneys from UUO mice. GFR in the 6-wk R-UUO kidneys was restored to 43 to 88% of the GFR in the contralateral unobstructed kidneys. This study describes the regenerative potential of the kidney after the established interstitial matrix expansion and medullary ablation associated with UUO in the adult mouse.     

Expression of renin and its mRNA in the adult rat kidney with chronic ureteral obstruction

Angiotensin II has been implicated in mediating renal vasoconstriction resulting from chronic unilateral ureteral obstruction (UUO) in both mature and developing animals. We have previously shown that chronic neonatal UUO results in increased distribution of renin and its mRNA in the obstructed kidney, as well as of immunoreactive renin in the intact opposite kidney. The present study was designed to evaluate the effects of 24 hours versus 4 weeks of UUO on the distribution of renin mRNA and its protein in the adult rat kidney. Renin was detected by immunocytochemistry using a polyclonal anti-rat renin antibody. Renin mRNA was localized by in situ hybridization to an oligonucleotide complementary to renin mRNA. UUO of 24 hours' or 4 weeks' duration did not alter the distribution of renin and its mRNA in the obstructed kidneys as compared with sham-operated kidneys, although kidneys obstructed for 4 weeks had a significant increase in the percent of renin-containing juxtaglomerular apparatuses (JCA) when compared with the intact opposite kidneys (P less than 0.05). Compensatory hypertrophy was not present in the intact opposite kidneys after 24 hours of UUO and distribution of renin gene expression was not altered at that time. However, 4 weeks following contralateral UUO, the intact kidneys were hypertrophied and showed a decrease in renin gene expression relative to the obstructed and sham-operated kidneys. We conclude that unlike UUO during early development, chronic UUO in the mature animal does not activate renin gene expression nor alter renin distribution in the obstructed kidneys. Renin gene expression is suppressed in the hypertrophied kidney with prolonged contralateral UUO.(ABSTRACT TRUNCATED AT 250 WORDS)     

Rapamycin attenuates unilateral ureteral obstruction-induced renal fibrosis

Unilateral ureteral obstruction (UUO) is a well-characterized hydronephrosis model exhibiting interstitial inflammatory-cell infiltration and tubular dilatation followed by tubulointerstitial fibrosis of the obstructed kidney. Our recent report indicates that rapamycin is effective for 50% of transplant recipients with chronic allograft nephropathy. In this study, we investigate the effect of rapamycin on UUO-induced renal fibrosis. UUO or sham-operated rats were randomly assigned to rapamycin or vehicle and were killed on days 7 and 14 after UUO or sham operation. Rapamycin decreased cross-sectional and gross-morphology changes in the obstructed kidney significantly. Rapamycin markedly blunted the increase in weight of the obstructed kidney, obstructed kidney length, and the obstructed/non-obstructed kidney weight ratio (by 74.6, 42.8, and 61.6% on day 14, respectively, all P<0.01). The scores for tubular dilatation, interstitial volume, interstitial collagen deposition, and alpha-smooth muscle actin (alpha-SMA) after UUO were significantly reduced by rapamycin. Rapamycin also decreased the number of infiltrative anti-ED1-positive cells and the gene expression of transforming growth factor (TGF)-beta1 (84.8 and 80.2% on day 7) after UUO (both P<0.01). By double immunostaining and Western analysis, rapamycin blocked the TGF-beta1-induced loss of E-cadherin expression and de novo increase of the expression of alpha-SMA in a dose-dependent manner. In conclusion, rapamycin significantly attenuated tubulointerstitial damage in a UUO-induced rat model of renal fibrosis, suggesting that rapamycin may have the potential to delay the progression of tubulointerstitial renal fibrosis.     

兔输尿管部分梗阻后肾脏血流动力学变化的实验研究

目的研究输尿管部分梗阻后积水肾脏的血流动力学变化。方法以40只实验大白兔制作单侧输尿管部分梗阻模型,于术前、术后1、2、4、8周随机选取10只进行高频彩色多普勒超声测定双侧肾动脉及肾内动脉的血流。结果梗阻后肾血管的血流速度明显降低,且舒张期血流速度降低的程度较收缩期明显得多。肾血管阻力指数逐渐增高,显著高于正常对照。梗阻解除后,肾血流迅速恢复,与正常对照相当。已经发生的病理改变恢复困难,但不再进一步恶化。结论肾脏的血流动力学改变可反映肾脏的功能状态,作为肾功能的评估指标有一定的实用意义。     

Contralateral renal hyperplasia and increased renal function after relief of chronic unilateral ureteral obstruction

Following relief of 1, 2 or 3 weeks of unilateral ureteral obstruction, contralateral compensatory renal growth and increased renal function were measured 3 and 6 months later. Compensatory growth occurred predominantly by hyperplasia, demonstrated by a significant increase in DNA content and a decrease in the RNA:DNA ratio (p less than 0.04). This is in contrast to compensatory growth following nephrectomy or unrelieved unilateral ureteral obstruction, which occurred primarily by hypertrophy with no significant change in DNA content but a significant increase in RNA content and the RNA:DNA ratio (p less than 0.04). Contralateral renal function in animals with relieved unilateral ureteral obstruction was greater than in controls with 2 normal kidneys (p less than 0.05). The contralateral increase in renal function was greater than that in animals subjected to ipsilateral nephrectomy or unrelieved ureteral obstruction, but this did not reach statistical significance. Thus, when growth occurred by hyperplasia, there was a trend to greater increases in renal function than when growth occurred by hypertrophy. Contralateral compensatory renal hyperplasia and increased renal function occurred in conjunction with a decrease in renal mass and function of the ipsilateral post-obstructed kidney. These experiments suggest that the post-obstructed, poorly functioning kidney stimulates contralateral hyperplastic growth and increased renal function. This hyperplastic response is different from the hypertrophic response following nephrectomy or unrelieved unilateral ureteral obstruction, implicating the post-obstructed kidney as the stimulus of the hyperplastic response.     

Refluxing ureteral reimplant as temporary treatment of obstructive megaureter in neonate and infant

PURPOSE: An obstructive megaureter identified in the neonatal period can be managed using a number of techniques, with the primary goal being to minimize the potential for further injury to the affected kidney. We describe our experience with refluxing ureteral reimplantation as a novel method for temporizing the obstructive megaureter. MATERIALS AND METHODS: Three patients identified prenatally with severe hydroureteronephrosis were confirmed following delivery to have an obstructive ectopic ureter. Unilateral obstruction was identified in 2 patients (1 female, 1 male). The third patient was a female with bilateral single system ectopic ureters. Treatment consisted of anastomosing the ureter proximal to the obstruction to the dome of the bladder in a freely high grade refluxing fashion. All of the patients were placed on antibiotic suppression after surgery. RESULTS: All patients demonstrated improved drainage of the affected kidney(s) following surgery. One female patient with unilateral obstruction had a poorly functioning kidney that showed no improvement of renal function 6 months following refluxing reimplantation, and laparoscopic nephrectomy was performed. The male patient with unilateral obstruction had adequate function with a significantly decreased ureteral diameter 1 year following refluxing ureteral reimplant, and a ureteral reimplantation without tapering was performed. The female patient with bilateral obstruction had 1 breakthrough urinary tract infection 6 months after surgery and now awaits second stage repair. CONCLUSIONS: Refluxing ureteral reimplantation is a safe, easy, beneficial and well tolerated means of temporizing the obstructive megaureter. This technique allows time for the child to mature, while accurately establishing renal function and preparing for a definitive surgical solution.     

Clusterin production in the obstructed rabbit kidney: correlations with loss of renal function.

Clusterin, a protein associated with cell death, has been suggested as a marker of renal injury. Correlation of clusterin gene expression with changes in renal function and quantitative measurement of clusterin protein levels after ureteral obstruction have not been previously reported. With unilateral ureteral obstruction in rabbits as the experimental model, the time course of alterations in renal function, clusterin mRNA accumulation, and concentrations of clusterin protein in serum, urine, and renal tissue were investigated. RBF, GFR, and renal concentrating ability (percent sodium reabsorption and urine osmolarity) all decreased (P < 0.05) in the obstructed kidney from control values within 1 day of ureteral obstruction. Clusterin mRNA levels started to rise in the ipsilateral kidney within 12 h of ureteral obstruction and increased up to 10-fold above control levels after 3 days of obstruction. Hybridization histochemistry showed that clusterin mRNA was initially detectable in collecting ducts and distal tubules within 12 h of ureteral obstruction. After 7 days of obstruction, increased accumulation of clusterin mRNA was also detectable in proximal tubular epithelial cells. Clusterin gene expression remained elevated in collecting ducts after 60 days of obstruction. Clusterin expression in the contralateral kidney was increased twofold over control values after 12 h of obstruction. No increase in clusterin mRNA accumulation was detectable after 24 h in the contralateral kidney. Total clusterin protein in the obstructed kidney increased from 0.59 +/- 0.66 (mean +/- 1 SD) to 2.5 +/- 1.3 micrograms after 7 days of ureteral obstruction (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Increased oxidative stress in mouse kidneys with unilateral ureteral obstruction.

BACKGROUND: Unilateral ureteral obstruction (UUO) is a well-established experimental model of renal injury leading to interstitial fibrosis. The molecular and cellular mechanism(s) of interstitial fibrosis in UUO kidney is beginning to be elucidated. Oxidative stress has been implicated in the pathogenesis of various forms of renal injury; however, little is known about its involvement in the setting of ureteral obstruction. METHODS: To investigate the possible involvement of oxidative stress in the obstructive nephropathy, we studied the occurrence and distribution of Nepsilon-carboxymethyl-lysine (CML) in the kidneys after ureteral obstruction. CML is an integrative biomarker of the cumulative protein damage induced by glycoxidation. Heme oxygenase-1 (HO-1) mRNA and protein expression, which is a sensitive and reliable indicator of oxidative stress, were also examined. RESULTS: CML immunoreactivity was found in the interstitium of UUO kidneys 10 days after the onset ureteral obstruction. HO-1 mRNA was up-regulated as early as 12 hours after ureteral obstruction. HO-1 immunoreactivity was observed in the periglomerular and peritubular interstitium two days after ureteral obstruction. CONCLUSIONS: These results strongly suggested the presence of increased oxidative stress in the interstitium of UUO kidneys. The oxidative stress and the formation of various kind of biological active oxidative products in the interstitium are supposed to play significant roles in UUO kidney.     

Refluxing ureterointestinal anastomosis for continent cutaneous urinary diversion

PURPOSE: We question the statement that anti-refluxing ureteral implantation is mandatory in low pressure, high capacity reservoirs. In a series of patients with ureteral obstruction after implantation with an anti-refluxing submucosal tunnel reimplantation was performed as a direct ureter-pouch anastomosis. The same technique was used for primary anastomosis in a later group of patients as the method of choice for ileocolic and colonic continent urinary diversion. MATERIALS AND METHODS: Direct ureteral reimplantation was performed in 10 patients in whom a total of 19 obstructed renal units were associated with an ileocolic reservoir. The retroperitoneal supracostal approach was used to avoid complications caused by repeat laparotomy. The ileocecal reservoir was opened superior and the obstructed ureter was identified and reimplanted via a buttonhole. The same technique was used for primary anastomosis in 20 patients (40 renal units), in whom the ureter was implanted in an ileocecal (10) or colonic (10) pouch. RESULTS: Postoperatively complications did not develop in any patient. Radiography of the pouch postoperatively showed renal reflux in only 1 renal unit. In the group with reimplanted ureters median followup was 81 months (range 10 to 120). Of the 19 obstructed ureters 14 returned to normal, while 5 showed persistent grade I dilatation. Median followup in patients with primary direct ureteral anastomosis was 20 months (range 2 to 36). Of the 22 preoperatively dilated systems 20 returned to normal and none of the 18 nondilated systems was obstructed. CONCLUSIONS: Direct ureter-pouch reimplantation proved to be simple and safe. When performed primarily for continent urinary diversion, the anastomosis was anti-refluxing in pouches with high capacity and low pressure. The advantage of this technique is the low risk of ureteral obstruction and subsequent deterioration in kidney function.