Salutary role for angiotensin in partial urinary tract obstruction

BACKGROUND: In the neonatal period, angiotensin II (Ang II) is up-regulated and induces a timely development of the renal pelvis and ureteral peristalsis, thereby protecting the kidney from hydronephrosis. We tested the possibility that in adulthood, Ang II may act salutarily on the kidney structure during partial urinary tract obstruction by inducing adaptive changes in the peristaltic machinery. METHODS: Adult male Sprague-Dawley rats were subjected to partial unilateral ureteral obstruction (UUO) and divided into two groups, that is, those treated with (group L, N = 21) and those without (group C, N = 21) an angiotensin type 1 (AT1) receptor antagonist (losartan). Control animals were sham operated (N = 10). Rats were sacrificed either at day 7 or day 14. RESULTS: The degree of hydronephrosis determined morphometrically was significantly more severe in group L than group C at both day 7 and day 14, indicating that Ang II inhibition accentuated hydronephrosis. The measurement of upstream pressure within the partially ligated ureter in vivo revealed that losartan significantly attenuates the frequency of ureteral peristaltic activities. In in vitro studies using ureteral strips harvested from normal adult Sprague-Dawley rats (N = 10), Ang II (10(-8) mol/L) was shown to augment contraction, which was completely inhibited by losartan (10(-6) mol/L). CONCLUSIONS: Ang II has a salutary effect of protecting kidneys from hydronephrosis during partial ureteral obstruction through its ability to augment ureteral peristalsis.     

Angiotensin type II receptor expression and ureteral budding

PURPOSE: Deletion of the angiotensin type II receptor gene (Agtr2) in mice results in a spectrum of urinary tract anomalies similar to that in humans. The mechanism behind this anomalous development is poorly understood. We evaluated Agtr2 expression as it relates to normal and abnormal ureteral budding. MATERIALS AND METHODS: A total of 400 wild type mice were inspected at birth for gross evidence of a urinary tract anomaly. In addition, the urinary tracts of 30 wild type embryos were evaluated at 11.0/11.5 and 13.5 weeks of gestation. These embryos were examined for ureteral budding site via section and whole mount in situ hybridization with c-ret probe and Agtr2 expression via in situ hybridization with Agtr2 riboprobe. There were 740 newborn mice homozygous for the null mutation of Agtr2 also evaluated along with 55 angiotensin type II knockout embryos at the aforementioned gestational ages. RESULTS: All wild type newborn animals were grossly normal. Of the angiotensin type II knockout newborns 23 (3.1%) had gross abnormalities of the urinary tract at birth. The predominant finding was a duplicated collecting system associated with a hydronephrotic upper pole moiety. These duplicated collecting systems fulfilled the Meyer-Weigert law. Interestingly, 25 (59.5%) of the knockout embryos showed abnormal ureteral budding. However, in wild type embryos Agtr2 was expressed at this "ectopic" cranial site between the wolffian duct and metanephric mesenchyme. CONCLUSIONS: Although not the sole regulator, angiotensin type II receptor expression may have a role in the embryological development of the urinary tract by inhibiting aberrant ureteral budding. A defect in this inhibitory process appears to cause ectopic ureteral budding, and may subsequently lead to renal dysplasia and other congenital anomalies of the kidney and urinary tract.     

Chemokine receptor CCR1 but not CCR5 mediates leukocyte recruitment and subsequent renal fibrosis after unilateral ureteral obstruction

As chemokine receptor CCR1 and CCR5 expression on circulating leukocytes is thought to contribute to leukocyte recruitment during renal fibrosis, the authors examined the effects of unilateral ureteral obstruction (UUO) in mice deficient for CCR1 or CCR5. Analysis of UUO kidneys from CCR1-deficient mice revealed a reduction of interstitial macrophages and lymphocytes (35% and 55%, respectively) compared with wild-type controls. CCR1-deficient mice had reduced CCR5 mRNA levels in UUO kidneys, which correlated with a reduction of CCR5+ T cell infiltrate as determined by flow cytometry. Interstitial fibroblasts, renal TGF-beta1 mRNA expression, interstitial volume, and collagen I deposits were all significantly reduced in CCR1-deficient mice. In contrast, renal leukocytes and fibrosis were unaffected in CCR5-deficient mice with UUO. However, if treated with the CCR1 antagonist BX471, CCR5-deficient mice showed a similar reduction of renal leukocytes and fibrosis as CCR1-deficient mice. To determine the underlying mechanism labeled macrophages and T cells isolated from either wild-type, CCR1-deficient, or CCR5-deficient mice were injected into wild-type mice with UUO. Three hours later, renal cell recruitment was reduced for CCR1-deficient cells or cells pretreated with BX471 compared with CCR5-deficient or wild-type cells. Thus, CCR1 but not CCR5 is required for leukocyte recruitment and fibrosis after UUO in mice. Therefore, CCR1 is a promising target for therapeutic intervention in leukocyte-mediated fibrotic tissue injury, e.g. progressive renal fibrosis.     

Glomerulotubular disconnection in neonatal mice after relief of partial ureteral obstruction

Ureteropelvic junction obstruction is a common cause of congenital obstructive nephropathy. To study the pathogenesis of nephropathy, a variable-partial, complete or a sham unilateral ureteral obstruction (UUO) was produced in mice within 2 days of birth. The obstruction was released in some animals at 7 days and kidneys harvested at 7-42 days of age for histologic and morphometric study. Renal parenchymal growth was stunted by partial UUO with the impairment proportional to the duration and severity of obstruction. Proximal tubule apoptosis and glomerulotubular disconnection led to nephron loss. Relief of partial UUO arrested glomerulotubular disconnection, resolved tubule atrophy, and interstitial fibrosis with remodeling of the renal architecture. Relief of severe UUO did not result in recovery. Compensatory growth of the contralateral kidney depended on the severity of obstruction. Our studies indicate that relief of moderate UUO will minimize nephron loss. Application of this technique to mutant mice will help develop future therapies to enhance nephron recovery.     

Transforming growth factor-beta induces renal epithelial jagged-1 expression in fibrotic disease

For elucidation of the mechanisms by which growth factors and cytokines affect renal epithelial cells, gene array analysis of renal cells cultured in the presence of transforming growth factor-beta1 (TGF-beta1) was performed. Many genes that were not previously considered to be involved in renal cell biologic processes were affected, one of which was jagged-1. The jagged ligand/notch receptor family controls the formation of boundaries between groups of cells and regulates cell fates. On the basis of the array analysis, jagged-1 expression was further evaluated in cultured cells and in C57BL/6 mice with a model of unilateral ureteral obstruction (UUO). Recombinant human TGF-beta1 increased jagged-1 mRNA levels at concentrations between 10(-11) and 10(-10) M. There was a commensurate increase in jagged-1 protein levels, as assessed by Western blotting. The expression of jagged-1 mRNA and protein was observed to be significantly increased in the kidneys of C57BL/6 mice with obstructed ureters, compared with the contralateral kidneys, at 7 and 14 d of UUO. Immunohistochemical analyses demonstrated jagged-1 expression in distal tubules of kidneys from normal mice or contralateral kidneys from mice with UUO. Jagged-1 protein expression was increased in tubules not yet in apparent atrophy in the kidneys with an obstructed ureter. Jagged-1 expression was significantly increased in the kidneys of normal mice treated with TGF-beta1 and was decreased in the kidneys of mice with UUO treated with a TGF-beta receptor II-Fc chimera. These results suggest that jagged-1 is expressed in normal kidneys and that this expression is upregulated during renal disease, in a TGF-beta-dependent manner.     

Telmisartan inhibits both oxidative stress and renal fibrosis after unilateral ureteral obstruction in acatalasemic mice.

BACKGROUND: Reactive oxygen species are involved in many of the angiotensin II signalling pathways. We have thus investigated whether the angiotensin II type 1 (AT1) receptor antagonist, telmisartan, can inhibit the accelerated renal fibrosis and excess oxidative stress, which occurs after unilateral ureteral obstruction (UUO) in acatalasemic mice. METHODS: The effect of daily intraperitoneal injection of telmisartan (0.1-0.3 mg/kg body weight) on the renal tubulointerstitial injury induced by UUO has been studied in homozygous acatalasemic mutant mice (C3H/AnLCs b Cs b) and wild-type mice (C3H/AnLCs a Cs a). We evaluated the systemic blood pressure of the mice on the seventh day. In addition, the tubulointerstitial expression of collagens type I and type IV, the p22-, p47- and p67-phox subunits of NADPH oxidase, 4-hydroxy-2-nonenal, and 4-hydroxy-2-hexenal lipid peroxidation products were assessed by immunohistochemistry. The level of apoptosis was determined by terminal deoxynucleotidyl transferase nick end-labelling analysis, while the mRNA level of the p22-, p47- and p67-phox subunits was quantified by real-time PCR. The renal content of each of the antioxidant enzymes catalase, glutathione peroxidase and superoxide dismutase was determined by specific assay. RESULTS: Obstructed kidneys from acatalasemic mice exhibited increased tubulointerstitial deposition in dilated tubules of collagens type I and IV, lipid peroxidation products, and the p22/p47/p67-phox subunits of NADPH oxidase. The level of the p22/p47/p67-phox subunit mRNA, and of apoptosis in tubular epithelial cells, was also increased compared with those from wild-type kidneys. Treatment with telmisartan attenuated all of the changes and prevented renal fibrosis in a dose-dependent manner; despite the low dose (0.1 mg/kg). The treatment did not lower the systemic blood pressure. The catalase activity remained low in acatalasemic obstructed kidneys without compensatory upregulation of glutathione peroxidase or superoxide dismutase activity; the level of neither anti-oxidant enzymes in obstructed kidneys was affected by telmisartan. CONCLUSIONS: The AT1 receptor antagonist telmisartan ameliorated renal fibrosis after UUO by inhibition of oxidative stress, even under acatalasemic conditions.     

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.     

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.     

Mannose receptor 2 attenuates renal fibrosis

Mannose receptor 2 (Mrc2) expresses an extracellular fibronectin type II domain that binds to and internalizes collagen, suggesting that it may play a role in modulating renal fibrosis. Here, we found that Mrc2 levels were very low in normal kidneys but subsets of interstitial myofibroblasts and macrophages upregulated Mrc2 after unilateral ureteral obstruction (UUO). Renal fibrosis and renal parenchymal damage were significantly worse in Mrc2-deficient mice. Similarly, Mrc2-deficient Col4α3(-/-) mice with hereditary nephritis had significantly higher levels of total kidney collagen, serum BUN, and urinary protein than Mrc2-sufficient Col4α3(-/-) mice. The more severe phenotype seemed to be the result of reduced collagen turnover, because procollagen III (α1) mRNA levels and fractional collagen synthesis in the wild-type and Mrc2-deficient kidneys were similar after UUO. Although Mrc2 associates with the urokinase receptor, differences in renal urokinase activity did not account for the increased fibrosis in the Mrc2-deficient mice. Treating wild-type mice with a cathepsin inhibitor, which blocks proteases implicated in Mrc2-mediated collagen degradation, worsened UUO-induced renal fibrosis. Cathepsin mRNA profiles were similar in Mrc2-positive fibroblasts and macrophages, and Mrc2 genotype did not alter relative cathepsin mRNA levels. Taken together, these data establish an important fibrosis-attenuating role for Mrc2-expressing renal interstitial cells and suggest the involvement of a lysosomal collagen turnover pathway.     

Effects of low molecular weight heparin in obstructed kidneys: decrease of collagen, fibronectin and TGF-beta, and increase of chondroitin/dermatan sulfate proteoglycans and macrophage infiltration.

BACKGROUND: Heparin exerts beneficial effects in different experimental models of nephropathy, as observed by the preservation of the structural morphology of the kidney after heparin therapy. Here we investigate molecular and cellular events involved in the protective effects of heparin in the progression of renal disease after unilateral ureteral obstruction. METHODS: Thirty-six rats were divided into six groups: group C (control) was not subjected to any surgical manipulation; group S (sham) was subjected to surgical manipulation but without ureteral ligation; group UUO was subjected to ureteral obstruction and received no treatment; group UUO + S was subjected to ureteral obstruction and received saline subcutaneously (s.c.) once daily; group UUO + H was subjected to ureteral obstruction and received low molecular weight heparin (LMW-Hep; 4 mg/kg) s.c. once daily; and group C + H was not subjected to any surgical manipulation and received LMW-Hep (4 mg/kg) s.c. once daily. After 14 days, the content of collagen, fibronectin, total glycosaminoglycans (GAGS), chondroitin sulfate/dermatan sulfate proteoglycans (CS/DSPGs), transforming growth factor-beta (TGF-beta) and cellular infiltration were determined in the kidneys by immunohistochemical and biochemical techniques. RESULTS: Collagen, fibronectin, total GAGS, CS/DSPGs, TGF-beta and cellular infiltration increased significantly in group UUO. LMW-Hep treatment reduced collagen, fibronectin and TGF-beta, but induced an increase in the content of total GAGS, CS/DSPGs and macrophage infiltration in group UUO + H when compared with group UUO. CONCLUSIONS: LMW-Hep diminishes fibrosis in obstructed kidneys by downregulating the synthesis of collagen, fibronectin and TGF-beta. The mechanisms underlying the overproduction of CS/DSPGs and the increase in cellular infiltration upon LMW-Hep administration remain to be elucidated.     

Compensatory renal growth due to neonatal ureteral obstruction: implications for clinical studies

In response to unilateral ureteral obstruction (UUO), the contralateral kidney undergoes compensatory renal growth, which is enhanced in early development. We investigated the renal growth response to UUO in the neonatal rat. Within 2 days of birth, animals were subjected to sham-operation, complete UUO, or variable partial UUO, and kidneys were harvested 3–60 days later. Contralateral kidney weight increased after only 7 days of complete UUO. Increase in contralateral kidney weight was not significant for partial UUO until 45 days, but kidney/body weight ratio increased after only 14 days of 0.3 mm partial UUO. The rate of contralateral renal growth increased with age and with increasing severity of UUO. In rats subjected to 45 days UUO, glomerular area was proportional to kidney/body weight ratio (r =0.61, p <0.01). We conclude that the rate of compensatory renal growth is dependent on the severity and duration of obstruction, and takes place at the single nephron level. The results suggest that biologic variability limits the early detection of compensatory renal growth, which is compounded by limitations in measuring renal size by clinical imaging. Factoring kidney length (or volume) by intervertebral length (or body surface area) should improve the precision of tracking renal growth.     

The intrinsic prostaglandin E2-EP4 system of the renal tubular epithelium limits the development of tubulointerstitial fibrosis in mice

Inflammatory responses in the kidney lead to tubulointerstitial fibrosis, a common feature of chronic kidney diseases. Here we examined the role of prostaglandin E(2) (PGE(2)) in the development of tubulointerstitial fibrosis. In the kidneys of wild-type mice, unilateral ureteral obstruction leads to progressive tubulointerstitial fibrosis with macrophage infiltration and myofibroblast proliferation. This was accompanied by an upregulation of COX-2 and PGE(2) receptor subtype EP(4) mRNAs. In the kidneys of EP(4) gene knockout mice, however, obstruction-induced histological alterations were significantly augmented. In contrast, an EP(4)-specific agonist significantly attenuated these alterations in the kidneys of wild-type mice. The mRNAs for macrophage chemokines and profibrotic growth factors were upregulated in the kidneys of wild-type mice after ureteral obstruction. This was significantly augmented in the kidneys of EP(4)-knockout mice and suppressed by the EP(4) agonist but only in the kidneys of wild-type mice. Notably, COX-2 and MCP-1 proteins, as well as EP(4) mRNA, were localized in renal tubular epithelial cells after ureteral obstruction. In cultured renal fibroblasts, another EP(4)-specific agonist significantly inhibited PDGF-induced proliferation and profibrotic connective tissue growth factor production. Hence, an endogenous PGE(2)-EP(4) system in the tubular epithelium limits the development of tubulointerstitial fibrosis by suppressing inflammatory responses.     

Osteopontin regulates renal apoptosis and interstitial fibrosis in neonatal chronic unilateral ureteral obstruction

Congenital obstructive nephropathy is a major cause of renal insufficiency in children. Osteopontin (OPN) is a phosphoprotein produced by the kidney that mediates cell adhesion and migration. We investigated the role of OPN in the renal response to unilateral ureteral obstruction (UUO) in neonatal mice. OPN null mutant (-/-) and wild-type (+/+) mice were subjected to sham operation or UUO within the first 2 days of life. At 7 and 21 days of age, fibroblasts (fibroblast-specific protein (FSP)-1), myofibroblasts (alpha-smooth muscle actin (SMA)), and macrophages (F4/80) were identified by immunohistochemical staining. Apoptotic cells were detected by terminal deoxy transferase uridine triphosphate nick end-labeling technique and interstitial collagen by Masson trichrome or picrosirius red stain. Compared to sham-operated or contralateral kidneys, obstructed kidneys showed increases in all parameters by 7 days, with further increases by 21 days. After 21 days UUO, there was an increase in tubular and interstitial apoptosis in OPN -/- mice as compared to +/+ animals (P<0.05). However, FSP-1- and alpha-SMA-positive cells and collagen in the obstructed kidney were decreased in OPN -/- compared to +/+ mice (P<0.05), whereas the interstitial macrophage population did not differ between groups. We conclude that OPN plays a significant role in the recruitment and activation of interstitial fibroblasts to myofibroblasts in the progression of interstitial fibrosis in the developing hydronephrotic kidney. However, OPN also suppresses apoptosis. Future approaches to limit the progression of obstructive nephropathy in the developing kidney will require targeting of specific renal compartments.     

PAI-1 deficiency attenuates the fibrogenic response to ureteral obstruction

BACKGROUND: Progressive renal disease is characterized by the induction of plasminogen activator inhibitor-1 (PAI-1), suggesting that impaired activity of the renal plasmin cascade may play a role in renal fibrosis. METHODS: To test this hypothesis, the severity of renal fibrosis caused by unilateral ureteral obstruction (UUO) was compared in PAI-1 wild-type (+/+) and PAI-1 deficient (-/-) mice. The extent of interstitial inflammation and fibrosis, renal plasminogen activator and plasmin activity, and renal expression of profibrotic genes was evaluated after 3, 7, and 14 days of UUO. RESULTS: Renal PAI-1 mRNA levels increased 8- to 16-fold in the +/+ mice after UUO surgery, and PAI-1 protein was detected in kidney homogenates. Interstitial fibrosis was significantly attenuated in -/- mice compared with +/+ mice at day 7 and day 14, based on the interstitial area stained with picrosirius red and total kidney collagen content. However, neither the mean renal plasminogen activator nor plasmin activities were increased in -/- mice compared with +/+ mice. The number of interstitial macrophages were significantly lower in the -/- mice three and seven days after UUO; interstitial myofibroblasts were significantly fewer at three days. At the same time points, this altered interstitial cellularity was associated with a significant reduction in renal mRNA levels for transforming growth factor-beta and procollagens alpha 1(I) and alpha 1(III). CONCLUSIONS: These studies establish an important fibrogenic role for PAI-1 in the renal fibrogenic response. The results demonstrate that one important fibrosis-promoting function of PAI-1 is its role in the recruitment of fibrosis-inducing cells, including myofibroblasts and macrophages.     

Effect of renal fibrosis after macrophage depletion in C3-deficient unilateral ureteral obstruction mice

Objective To investigate the effect and mechanism of renal fibrosis after macrophage depletion in C3-deficient unilateral ureteral obstruction mice. Methods Renal interstitial fibrosis model was established by unilateral ureteral obstruction (UUO) in male C3-deficient mice and age-matched C57BL/6 WT mice (8-12 weeks of age). Mice were randomly divided into 4 groups, including sham operation in wild type group（WT/sham）(n=18), UUO operation in wild type group（WT/UUO）(n=18), sham operation in C3-deficient group（C3KO/sham）(n=18), and UUO operation in C3-deficient group（C3KO/UUO）(n=18). The expression of complement C3 was detected by immunohistochemical staining and renal interstitial macrophages were assessed by immunofluorescence staining. Tubulointerstitial fibrosis was observed by both HE staining and Masson staining after 14 days of UUO. Collagen accumulation and score of tubulointerstitial injury were obtained. Wild type and C3-deficient UUO mice were treated by liposome clodronate in early or late stage respectively and then interstitially infiltrated macrophages and renal fibrosis were analysed. Mice were sacrificed randomly at 3,7,14 days after UUO and obstructed kidneys were collected. Macrophage phenotype was detected by double-labeling immunofluorescence with F4/80 and iNOS for the M1, F4/80 and CD206 for the M2 macrophage subpopulation. iNOS, Arg-1 and CD206 were also detected by western blot. Results C3 deficient mice exhibited attenuated renal fibrosis, reduced collagen accumulation and tubulointerstitial injury score compared with WT mice (P＜0.01). Meanwhile, macrophage depletion in early or late stage of UUO reduced renal fibrosis in WT mice, but had no effect on C3-deficient UUO mice. Decreased accumulation of M1 macrophages and expression of iNOS, increased accumulation of M2 macrophages and expression of Arg-1, CD206 were found in C3 deficient mice compared with WT mice in early stage of UUO (P＜0.01). Conclusion Renal fibrosis is not reduced after depletion of macrophages in C3 deficient UUO mice due to the altered macrophage polarization.     

ccccc逆行输尿管软镜钬激光碎石术治疗孤立肾肾结石的疗效观察

目的 探讨输尿管软镜钬激光碎石术在治疗孤立肾肾结石中的临床应用价值.方法 回顾分析本院使用奥林巴斯电子输尿管软镜钬激光碎石处理的39例孤立肾肾结石患者的临床资料,其中肾盂肾盏多发性结石20例,孤立肾感染性结石4例,肾盏憩室内结石10例,肾盏嵌顿结石4例,多发性肾乳头黏膜下钙化1例.术中先行输尿管硬镜镜检,留置斑马导丝并放置F12～ 14输尿管扩张鞘后经鞘或直接沿斑马导丝入镜.软镜进入肾盂后首先镜下观察肾盂及上、中、下各盏并定位结石,根据结石位置选用365μm或200μm光纤,功率选择在0.5～1J、15～ 30Hz范围,以表面蚕蚀、周缘穿孔、中央穿孔等方法将结石完全粉碎2mm以内,若患者留置输尿管鞘,则以冲水引流、套石蓝取石等方法将结石取出或部分取出.所有患者常规留置DJ管2周,术后第1d拔除导尿管,术后2周拔除DJ管,术后4周常规复查泌尿系平片（KUB）或双肾CT平扫,评估结石排净率.残留结石≥4mm为有临床意义的结石残留.结果 本组39例患者34例成功置放输尿管鞘,输尿管镜鞘放置成功率87.2％,进镜成功率100％,术中寻找结石成功率100％.一期手术成功碎石33例,结石均排尽或残余结石＜4mm,无需进一步处理.另3例下盏憩室内结石,2例下盏结石,1例肾乳头黏膜下钙化结石/残石均≥4mm,辅助体外冲击波碎石或2期输尿管软镜手术.结论 输尿管软镜对比经皮肾镜,具有微创安全、手术并发症少的特点,而且几乎可以达到肾内集合系统所有位置,结合钬激光适合治疗各类孤立肾肾结石.     

逆行输尿管软镜钬激光碎石术治疗孤立肾肾结石的疗效观察

目的:探讨输尿管软镜钬激光碎石术在治疗孤立肾肾结石中的临床应用价值。方法：回顾分析本院使用奥林巴斯电子输尿管软镜钬激光碎石处理的39例孤立肾肾结石患者,其中肾盂肾盏多发性结石20例,孤立肾感染性结石4例,肾盏憩室内结石10例,肾盏嵌顿结石4例,多发性肾乳头黏膜下钙化1例。术中先行输尿管硬镜镜检,留置斑马导丝并放置F12～14输尿管扩张鞘后经鞘或直接沿斑马导丝入镜。软镜进入肾盂后首先镜下观察肾盂及上、中、下各盏并定位结石,根据结石位置选用365μm或200μm光纤,功率选择在0.5～1J、15～30Hz范围,以表面蚕蚀、周缘穿孔、中央穿孔等方法将结石完全粉碎2mm以内,若患者留置输尿管鞘,则以冲水引流、套石蓝取石等方法将结石取出或部分取出。所有患者常规留置DJ管2周,术后第1天拔除导尿管,术后2周拔除DJ管,术后4周常规复查泌尿系平片(KUB)或双肾CT平扫,评估结石排净率。残留结石≥4mm为有临床意义的结石残留。结果：本组39例患者34例成功置放输尿管鞘,输尿管镜鞘放置成功率87.2%,进镜成功率100%,术中寻找结石成功率100%。一期手术成功碎石33例,结石均排尽或残余结石<4mm,无需进一步处理。另3例下盏憩室内结石,2例下盏结石,1例肾乳头黏膜下钙化结石/残石均≥4mm,辅助体外冲击波碎石或2期输尿管软镜手术。结论：输尿管软镜对比经皮肾镜,具有微创安全,手术并发症少的特点,而且几乎可以达到所有肾内集合系统所有位置,结合钬激光适合治疗各类孤立肾肾结石。     

Smad3 deficiency attenuates renal fibrosis, inflammation,and apoptosis after unilateral ureteral obstruction

BACKGROUND: Transforming growth factor-beta (TGF-beta) has been implicated in the development of renal fibrosis induced by unilateral ureteral obstruction (UUO). However, there is little information on signaling pathways mediating TGF-beta activity involved in molecular and cellular events leading to renal fibrosis induced by UUO. In this study, we sought to determine whether Smad3, a major signaling component of TGF-beta, mediated renal fibrosis induced by UUO. METHODS: Renal fibrosis, inflammation, and apoptosis induced by UUO were macroscopically and histologically compared between wild-type mice and Smad3 null mice. RESULTS: Gross appearance of the kidney after UUO showed relatively intact kidney in Smad3 null mice [Smad3(-/-) mice] when compared with that of wild-type mice [Smad3(+/+) mice]. Renal interstitial fibrosis based on the interstitial area stained with Aniline-blue or Sirius red solution was significantly attenuated in the obstructed kidney of Smad3(-/-) mice when compared with that of Smad3(+/+) mice. Deposition of type I and type III collagens were also significantly reduced in the obstructed kidney of Smad3(-/-) mice. In addition, the numbers of myofibroblasts, macrophages, and CD4/CD8 T cells infiltrated into the kidney after UUO were significantly attenuated in the obstructed kidney of Smad3(-/-) mice when compared with that of Smad3(+/+) mice. Furthermore, terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) staining after UUO showed significantly reduced number of tubular apoptotic cells in the obstructed kidney of Smad3(-/-) mice when compared with that of Smad3(+/+) mice. Endogenous Smad pathway was activated in the obstructed kidney after UUO in wild-type mice as judged by the increase of phosphorylated Smad2 or phosphorylated Smad2/3-positive cells in renal interstitial area. CONCLUSION: Smad3 deficiency attenuated renal fibrosis, inflammation, and apoptosis after UUO, suggesting that Smad3 was a key molecule mediating TGF-beta activity leading to real fibrosis after UUO.     

Role of nitric oxide in renal tubular apoptosis of unilateral ureteral obstruction

BACKGROUND: The obstructed kidney in unilateral ureteral obstruction (UUO) is characterized by renal atrophy and tissue loss, which is mediated by renal tubular apoptosis. We sought to determine whether NO is involved in renal tubular apoptosis in vitro and in vivo. METHODS: Rat renal tubular epithelial cells (NRK-52E) were subjected to mechanical stretch, and apoptosis and cell size were analyzed by flow cytometry. Furthermore, we studied UUO in mice lacking the gene for inducible nitric oxide synthase (iNOS-/-) and their wild-type littermates. Tubular apoptosis and proliferation were detected by immunostaining. NOS activity and NOS expression were assessed by a citrulline assay and Western blot, respectively. RESULTS: Stretching-induced apoptosis in NRK-52E, which was reduced when NO was increased; conversely, stretch-induced apoptosis was increased when a NOS inhibitor was added to the cells. Stretched cells are larger and more apoptotic than unstretched cells. In UUO, the obstructed kidney of iNOS-/- mice exhibited more apoptotic renal tubules than the wild-type mice through 14 days of UUO. The obstructed kidney of iNOS-/- mice at day 3 showed more proliferative tubules compared with wild type. The obstructed kidney of wild-type mice exhibited higher total NOS activity until day 7 after UUO compared with iNOS-/- mice. However, the obstructed kidney of day 14 wild-type mice exhibited significantly lower iNOS activity and protein compared with the day 0 kidney. CONCLUSION: These results suggest that mechanical stretch is related to renal tubular apoptosis and that NO plays a protective role in this system in UUO.