Renoprotective effects of a dipeptidyl peptidase 4 inhibitor in a mouse model of progressive renal fibrosis

Although the effects of dipeptidyl peptidase 4 (DPP-4) inhibitors beyond their hypoglycemic action have been reported, whether these inhibitors have renoprotective effects in nondiabetic chronic kidney disease (CKD) is unclear. We examined the therapeutic effects of DPP-4 inhibition in mice with unilateral ureteral obstruction (UUO), a nondiabetic model of progressive renal fibrosis. After UUO surgery, mice were administered either the DPP-4 inhibitor alogliptin or a vehicle by oral gavage once a day for 10 days. Physiological parameters, degrees of renal fibrosis and inflammation, and molecules related to renal fibrosis and inflammation were then evaluated using sham-operated mice as controls. Positive area of α-smooth muscle actin was significantly smaller and expression of transforming growth factor β messenger RNA was significantly lower in the alogliptin-treated group than in the vehicle-treated group. Renal total collagen content was also significantly lower in the alogliptin-treated group than in the vehicle-treated group. These results suggest that alogliptin exerted renoprotective antifibrotic effects. The positive area of F4/80 was significantly smaller and expression of CD68 messenger RNA was significantly lower in the alogliptin-treated group than in the vehicle-treated group, suggesting an anti-inflammatory action by the DPP-4 inhibitor. Compared to the results for the vehicle-treated group, expression of markers for M1 macrophages tended to be lower in the alogliptin-treated group, and the relative expression of M2 macrophages tended to be higher. These data indicate the various protective effects of DPP-4 inhibition in nondiabetic mice with UUO. DPP-4 inhibitors may therefore be promising therapeutic choices even for nondiabetic CKD patients.     

Tubular mitochondrial AKT1 is activated during ischemia reperfusion injury and has a critical role in predisposition to chronic kidney disease

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趋化因子CX3CL1及其受体CX3CR1在肾脏纤维化中的表达和作用

目的 探讨趋化因子CX3CL1及其受体CX3CR1在慢性肾脏病(chronic kidney disease,CKD)患者和单侧输尿管结扎(unilateral ureter obstruction,UUO)模型小鼠肾脏组织中的表达水平及其与肾脏纤维化的关系.方法 ①用免疫组化方法检测30例首诊CKD患者和10例健康对照组肾脏活检组织中CX3CL1和CX3CR1的表达;②分别用免疫印记和免疫组化方法,分析CKD患者第7、14天单侧输尿管梗阻(unilateral ureter obstruction,UUO)和正常对照组小鼠肾脏组织中CX3CL1和CX3CR1的表达水平;③用免疫荧光检测CX3CR1-/-小鼠与野生型UUO模型小鼠肾脏纤维化和巨噬细胞浸润的程度.结果 发现首诊CKD患者肾脏组织CX3CR1和CX3CL1表达水平明显高于健康对照组(P＜0.05);UUO模型小鼠肾脏CX3CL1和CX3CR1的表达水平较正常对照组明显增高(P＜0.05),且第14天较第7天小鼠肾脏组织CX3CL1和CX3CR1的表达水平也明显增高(P＜0.05);此外,与野生型UUO模型小鼠相比,CX3CR1-/-UUO模型小鼠肾脏组织中α平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)表达和巨噬细胞数量明显减少(P＜0.05).结论 本研究表明,首诊CKD患者和UUO模型小鼠肾脏组织中CX3CL1和CX3CR1表达水平明显增高.肾脏组织中CX3CL1和CX3CR1的过表达可能与肾脏组织纤维化的发生、发展密切相关.     

血小板反应蛋白-1及其受体CD47在肾间质纤维化血管病变中的表达

目的观察血小板反应蛋白-1(TSP-1)及其受体CD47在单侧输尿管梗阻(UUO)大鼠模型中的表达,探讨TSP-1-CD47在肾周毛细血管(PTC)病变中的作用。 方法将60只SD大鼠随机分为2组：UUO组45只和假手术组(SOR) 15只。UUO组随机选取15只分别于术后3 d、7 d、14 d处死;SOR组随机选取5只于相同时间点处死。检测24 h尿蛋白定量,采用全自动生化分析仪检测各组大鼠的肾功能,通过Masson染色观察肾间质病理改变;免疫荧光双染色观察TSP-1及其受体CD47在UUO模型中是否存在共表达。Western印迹检测毛细血管病变指标CD34和血管内皮生长因子(VEGF)及TSP-1的表达;多组间均数比较使用方差分析;TSP-1与CD34、VEGF的相关性进行Pearson相关分析。 结果与SOR组相比,UUO各组大鼠血清肌酐、尿素氮、24 h尿蛋白定量随梗阻时间延长无明显变化,但肾间质纤维化逐渐加重,肾小管损伤评分增加。免疫荧光双染色显示TSP-1及其受体CD47在肾小管间质存在共表达。Western印迹检测显示随UUO时间延长,TSP-1蛋白水平逐渐增加,而CD34及VEGF蛋白表达随梗阻时间延长逐渐下降。相关分析显示TSP-1蛋白水平与CD34及VEGF的表达呈负相关(r＝－0.931, P<0.01;r＝－0.953, P<0.01)。 结论TSP-1及其受体CD47在UUO大鼠模型肾间质存在共表达,且与PTC呈负相关。TSP-1可能通过CD47参与UUO肾脏PTC病变的发生发展。     

1型糖尿病肾病尿毒症期患者胰肾联合移植与单独肾移植远期疗效观察

目的研究1型糖尿病肾病尿毒症期患者胰肾联合移植（simultaneouspancreas—kidneytransplantation,SPK）与单独肾移植（kidneytransplantationalone,KTA）的长期临床效果。方法选取2001年10月至2004年7月在南方医科大学南方医院接受SPK和KTA的1型糖尿病肾病尿毒症期患者共16例,其中SPK组6例,KTA组10例。回顾性分析和比较两组5年人／移植物存活率、急性排斥反应和蛋白尿的发生率及空腹血糖、血肌酐、血脂（甘油三酯、胆固醇）、血压水平。结果16例受者至今存活。SPK组移植胰腺功能正常,1例于移植后第5年血肌酐升至450μmol／L左右,尿蛋白阳性,其余受者血肌酐均不超过130μmol／L,尿蛋白阴性,5年人／移植物存活率均为100％。KTA组3例血肌酐浓度为150～180μmol／L,尿蛋白阳性,1例于移植后第4年因血肌酐升至700μmol／L以上开始规律血液透析治疗,5年人／移植物存活率为100％和90％。两组急性排斥反应的发生率差异无统计学意义（P〉0．05）。移植后5年SPK组和KTA组血肌酐平均浓度为（166．3±139．3）μmol／L和（209．8±188．6）μmoL／L,蛋白尿、高血脂、高血压的发生率分别为16．7％、33．3％、50％和40％、60％、80％,SPK组均低于KTA组,但差别无统计学意义（均P〉0．05）;而血糖水平、胆固醇浓度、收缩压水平SPK组均低于KTA组,差别有统计学意义（均P〈0．05）。结论SPK是1型糖尿病肾病尿毒症期患者的有效治疗方法,与KTA比较,其移植后5年的移植肾功能较好,高血脂、高血压的发生率较低。     

乌司他丁对脓毒症急性肾损伤大鼠肾脏NOD1受体和血IL-18水平的影响

目的 探讨乌司他丁对腹主动脉阻断联合腹腔注射脂多糖内毒素（LPS）构建严重脓毒症大鼠肾脏NOD1受体表达和血IL-18水平的影响.方法 48只Wistar大鼠随机分为假手术组（SHAM组）、腹主动脉阻断联合腹腔注射LPS组（AAC＋ LPS组）、腹主动脉阻断联合腹腔注射LPS乌司他丁干预组（AAC＋ LPS＋U组）、腹主动脉阻断腹腔LPS生理盐水对照组（AAC＋ LPS＋ NS组）.大鼠于术后或干预后8h处死,收集血和大鼠肾脏,检测血中Cr、BUN水平,ELISA方法检测血中IL-18浓度,免疫组化方法检测肾脏NOD1蛋白的表达,RT-PCR方法检测肾脏NOD1 mRNA的表达.结果 NOD1受体mRNA和蛋白的表达,血中IL-18和Cr、BUN水平在AAC ＋LPS组和AAC＋LPS ＋NS组最强,AAC＋ LPS＋U组较前两组下降,差异有统计学意义（P＜0.05）.结论 乌司他丁可能通过抑制肾脏NOD1受体的表达,抑制血中IL-18的分泌从而在脓毒症时发挥抗炎和肾脏保护作用.     

Macrophage accumulation and renal fibrosis are independent of macrophage migration inhibitory factor in mouse obstructive nephropathy

BACKGROUND AND AIM: The progression of renal injury, initiated by either an immune or non-immune insult, is closely associated with the accumulation of leucocytes and fibroblasts in the damaged kidney. Macrophage migration inhibitory factor (MIF) regulates leucocyte activation and fibroblast proliferation in vitro. Studies have identified a pathological role for MIF in immune-initiated renal injury in the rat. In this study, we examined the role of MIF in obstructive nephropathy, where renal injury is initiated by a non-immune insult. METHODS AND RESULTS: Unilateral ureteric ligation was performed on MIF wildtype (+/+) and MIF deficient (-/-) mice. Groups of five mice were killed at days 0, 1, 5 or 10 after obstruction, and kidneys were examined via immunohistochemistry and northern blotting. In MIF +/+ mice, expression of the MIF protein increased in obstructed kidneys compared to normal control kidneys. Interstitial macrophage and T cell accumulation was significantly increased in obstructed kidneys at day 5 and 10, but was unaffected by MIF deficiency. Osteopontin and macrophage colony stimulating factor (M-CSF) mRNA expression in obstructed kidneys were equally increased in both genotypes, indicating that expression of these chemokines is not influenced by MIF. No difference was detected in the development of renal fibrosis in obstructed MIF +/+ and MIF -/- kidneys, as assessed by myofibroblast accumulation and proliferation and expression of profibrotic molecules (transforming growth factor-beta 1(TGF-beta1) and collagen). CONCLUSION: These results demonstrate that MIF expression is increased in obstructive nephropathy without affecting kidney leucocyte accumulation or the development of renal fibrosis. This suggests that the progression of renal injury in obstructive nephropathy is independent of MIF.     

慢性马兜铃酸肾病血小板反应因子1高表达与肾间质纤维化及微血管丢失的关系

目的 探讨血小板反应因子1（TSP-1）与慢性马兜铃酸肾病（CAAN）肾间质纤维化及肾小管周围毛细血管（PTC）丢失的关系。方法 36只SD大鼠被随机分为CAAN模型组（用关木通浸膏水溶液间断灌胃）及对照组（仅自来水灌胃），每组18只。分别于第4、8和12周处死6只大鼠，用肾组织切片做免疫组化染色。对TSP-1、转化生长因子-β1（TGF-β1）、氨基肽酶P（APP）、血管内皮生长因子（VEGF）及Ⅰ型胶原（ColⅠ）的表达进行半定量分析。结果 与对照组比较，模型组大鼠肾间质TSP-1、肾小管TGF-β1及肾间质Col Ⅰ表达均显著上调（P均〈0．01）。3者间表达量呈显著正相关（r=0．925、0．910、0．857，P均〈0．01）。模型组大鼠肾间质APP表达明显下调（P〈0．01），与TSP-1、Col Ⅰ表达量呈显著负相关（r=-0．945、-0．883，P均〈0．01）。模型组肾小管VEGF表达上调（P〈0．01），其表达量与APP呈显著负相关（r=-0．607，P〈0．01），而与TGF-β1星显著正相关（r=0．625，P〈0．01）。结论 TSP-1-TGF-β轴表达增强及与TSP-1相关的PTC丢失均可能参与CAAN肾间质纤维化，而VEGF表达上调为代偿表现。     

Conjugated dienes: a critical trait of lipoprotein oxidizability in renal fibrosis.

BACKGROUND: We assessed whether a differential oxidizability of apolipoprotein B (apo B)-containing lipoproteins (LDL and VLDL) may explain the oxidative stress that we had observed at the onset of renal fibrosis in Zucker obese (ZO) rats (Nephrol Dial Transplant 2000, 15: 467--476). METHODS: Ex vivo copper-induced oxidation of lipoproteins was performed in 1-, 3-, and 9-month-old ZO and age-matched lean (ZL) rats. LDL/VLDL oxidizability was determined by spectrophotometry at 234 nm by monitoring the formation of conjugated diene hydroperoxides. RESULTS: A significant increase in lag time (reflecting the resistance to oxidation) was observed in ZO rats at 3 months while the maximal diene production (reflecting the amount of hydroperoxides formed during oxidation) was higher in ZO than in ZL rats as early as 1 month. Lipoproteins were larger in ZO than in ZL rats, as shown by their core to surface component ratio. Furthermore, ZO lipoproteins had increased vitamin E and polyunsaturated fatty acid (PUFA) content, with no change in vitamin E/PUFA ratio. CONCLUSIONS: Rather than oxidizability of apo B-containing lipoproteins, the ability of these molecules to produce high levels of conjugated dienes, which can act as toxic tissue messengers, appears to be a critical trait in the development of renal fibrosis in this rat model of obesity and renal fibrosis.     

A profile of multiple circulating tumor necrosis factor receptors associated with early progressive kidney decline in Type 1 Diabetes is similar to profiles in autoimmune disorders

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