FTO-mediated m6A mRNA demethylation aggravates renal fibrosis by targeting RUNX1 and further enhancing PI3K/AKT pathway.

Chronic kidney disease (CKD) is a global health burden, with ineffective therapies leading to increasing morbidity and mortality. Renal interstitial fibrosis is a common pathway in advanced CKD, resulting in kidney function and structure deterioration. In this study, we investigate the role of FTO-mediated N6-methyladenosine (m6A) and its downstream targets in the pathogenesis of renal fibrosis. M6A modification, a prevalent mRNA internal modification, has been implicated in various organ fibrosis processes. We use a mouse model of unilateral ureteral obstruction (UUO) as an in vivo model and treated tubular epithelial cells (TECs) with transforming growth factor (TGF)-ß1 as in vitro models. Our findings revealed increased FTO expression in UUO mouse model and TGF-ß1-treated TECs. By modulating FTO expression through FTO heterozygous mutation mice (FTO+/- ) in vivo and small interfering RNA (siRNA) in vitro, we observed attenuation of UUO and TGF-ß1-induced epithelial-mesenchymal transition (EMT), as evidenced by decreased fibronectin and N-cadherin accumulation and increased E-cadherin levels. Silencing FTO significantly improved UUO and TGF-ß1-induced inflammation, apoptosis, and inhibition of autophagy. Further transcriptomic assays identified RUNX1 as a downstream candidate target of FTO. Inhibiting FTO was shown to counteract UUO/TGF-ß1-induced RUNX1 elevation in vivo and in vitro. We demonstrated that FTO signaling contributes to the elevation of RUNX1 by demethylating RUNX1 mRNA and improving its stability. Finally, we revealed that the PI3K/AKT pathway may be activated downstream of the FTO/RUNX1 axis in the pathogenesis of renal fibrosis. In conclusion, identifying small-molecule compounds that target this axis could offer promising therapeutic strategies for treating renal fibrosis.

The application of new complex indicators in the detection of urine.

BACKGROUND: Accurate diagnosis and assessment of hematuria is crucial for the early detection of chronic kidney disease(CKD). As instability of urinary RBC count (URBC) often results with clinical uncertainty, therefore new urinary indexes are demanded to improve the accuracy of diagnosis of hematuria. In this study, we aimed to investigate the benefit of applying new complex indicators based on random urine red blood cell counts confirmed in hematuric kidney diseases. METHODS: All patients enrolled underwent renal biopsy, and their clinical information was collected. Urinary and blood biomedical indexes were implemented with red blood cell counts to derive complex indicators. Patients were divided into two groups (hematuria-dominant renal histologic lesions and non-hematuria-dominant renal histologic lesions) based on their renal pathological manifestations. The target index was determined by comparing the predictive capabilities of the candidate parameters for hematuric kidney diseases. Hematuria stratification was divided into four categories based on the scale of complex indicators and distributional features. The practicality of the new complex indicators was demonstrated by fitting candidate parameters to models comprising demographic information. RESULTS: A total of 1,066 cases (678 hematuria-dominant renal histologic lesions) were included in this study, with a mean age of 44.9 ± 15 years. In differentiating hematuria-dominant renal histologic lesion from the non-hematuria-dominant renal histologic lesion, the AUC value of "The ratio of the random URBC to 24-h albumin excretion" was 0.76, higher than the standard approach of Lg (URBC) [AUC = 0.744] (95% Confidence interval (CI) 0.712 ~ 0.776). The odds ratio of hematuria-dominant renal histologic lesion (Type I) increased from Q2 (3.81, 95% CI 2.66 ~ 5.50) to Q4 (14.17, 95% CI 9.09 ~ 22.72). The predictive model, composed of stratification of new composite indexes, basic demographic characteristics, and biochemical parameters, performed best with AUC value of 0.869 (95% CI 0.856-0.905). CONCLUSION: The new urinary complex indicators improved the diagnostic accuracy of hematuria and may serve as a useful parameter for screening hematuric kidney diseases.

Preemptive renal replacement therapy in post-cardiotomy cardiogenic shock patients: a historically controlled cohort study.

BACKGROUND: The aim of the study was to evaluate whether the preemptive renal replacement therapy (RRT) might improve outcomes in post-cardiotomy cardiogenic shock (PCCS) patients. METHODS: In Period A (September 2014-April 2016), patients with PCCS received RRT, depending on conventional indications or bedside attendings. In Period B (May 2016-November 2017), the preemptive RRT strategy was implemented in all PCCS patients in our intensive care unit. The goal-directed RRT was applied for the RRT patients. The hospital mortality and renal recovery were compared between the two periods. RESULTS: A total of 155 patients (76 patients in Period A and 79 patients in Period B) were ultimately enrolled in this study. There were no significant differences in demographic characteristics and intraoperative and postoperative parameters between the two groups. The duration between surgery and RRT initiation was significantly shorter in Period B than in Period A [23 (17, 66) vs. 47 (20, 127) h, P<0.01]. The hospital mortality in Period B was significantly lower than that in Period A (38.0% vs. 59.2%, P<0.01). There were fewer patients with no renal recovery in Period B (4.1% vs. 19.4%, P=0.026). Patients in Period B displayed a significantly shorter time to completely renal recovery (12±15 vs. 25±15 d, P<0.05). CONCLUSIONS: Among PCCS patients, preemptive RRT compared with conventional initiation of RRT reduced mortality in hospital and also led to faster and more frequent recovery of renal function. Our preliminary study supposed that preemptive initiation of RRT might be an effective approach to PCCS with acute kidney injury (AKI).

Reversible preoperative renal dysfunction does not add to the risk of postoperative acute kidney injury after cardiac valve surgery.

OBJECTIVE: To evaluate the impact of the renal dysfunction (RD) type and change of postoperative cardiac function on the risk of developing acute kidney injury (AKI) in patients who underwent cardiac valve surgery. METHOD: Reversible renal dysfunction (RRD) was defined as preoperative RD in patients who had not been initially diagnosed with chronic kidney disease (CKD). Cardiac function improvement (CFI) was defined as postoperative left ventricular ejection function - preoperative left ventricular ejection function (ΔEF) >0%, and cardiac function not improved (CFNI) as ΔEF ≤0%. RESULTS: Of the 4,805 (94%) cardiac valve surgery patients, 301 (6%) were RD cases. The AKI incidence in the RRD group (n=252) was significantly lower than in the CKD group (n=49) (36.5% vs 63.3%, P=0.018). The AKI and renal replacement therapy incidences in the CFI group (n=174) were significantly lower than in the CFNI group (n=127) (33.9% vs 50.4%, P=0.004; 6.3% vs 13.4%, P=0.037). After adjustment for age, gender, and other confounding factors, CKD and CKD + CFNI were identified as independent risk factors for AKI in all patients after cardiac valve surgery. Multivariate logistic regression analysis showed that the risk factors for postoperative AKI in preoperative RD patients were age, gender (male), hypertension, diabetes, chronic heart failure, cardiopulmonary bypass time (every 1 min added), and intraoperative hypotension, while CFI after surgery could reduce the risk. CONCLUSION: For cardiac valve surgery patients, preoperative CKD was an independent risk factor for postoperative AKI, but RRD did not add to the risk. Improved postoperative cardiac function can significantly reduce the risk of postoperative AKI.

Significance of perioperative goal-directed hemodynamic approach in preventing postoperative complications in patients after cardiac surgery: a meta-analysis and systematic review.

PURPOSE: Goal-directed hemodynamic therapy (GDT) is used to prevent hypoperfusion resulting from surgery. The objective of this study was to analyze the efficacy and importance of perioperative GDT. METHODS: PUBMED, MEDLINE, CENTRAL, and Google Scholar databases were searched until 17 June 2016 using the search terms: cardiac output, cardiac surgical procedures, hemodynamics, goal-directed therapy, and intraoperative. Randomized-controlled trials with pre-emptive hemodynamic intervention for cardiac surgical population versus standard hemodynamic therapy were included. RESULTS: Nine studies were included with a total of 1148 patients. The overall analysis revealed no significant difference in the all-cause mortality (pooled peto OR =0.58, 95%CI =0.27-1.525, p = 0.164), duration of mechanical ventilation (pooled difference in mean= -1.48, 95%CI= -3.24 to 0.28, p = 0.099), or length of intensive care unit (ICU) stay (pooled difference in mean= -9.10, 95%CI= -20.14 to 1.93, p = 0.106) between patients in the GDT and control groups. Patients in the GDP group were associated with shorter hospital stay than those in the control group (pooled difference in mean= -1.52, 95%CI= -2.31 to -0.73, p < 0.001). CONCLUSION: GDT reduces the length of hospital stay compared with the standard of care. Further studies are necessary to continually assess the benefit of GDT following major surgery. Key Messages The results of this analysis revealed no significant difference between cardiac surgery patients receiving goal-directed hemodynamic therapy (GDT) or conventional fluid therapy in terms of the all-cause mortality, duration of mechanical intervention, and length of ICU-stay. The length of hospital stay was significantly reduced in patients treated with GDT compare to conventional fluid therapy. GDT may have limited benefit in reducing mortality; however, the association to shorter length of hospital stay may suggest that better hemodynamic balance can facilitate postoperative recovery.

Risk Factors for Long-Term Mortality and Progressive Chronic Kidney Disease Associated With Acute Kidney Injury After Cardiac Surgery.

The aim of the study was to evaluate risk factors for long-term mortality and progressive chronic kidney disease (CKD) after cardiac surgery in patients with normal preoperative renal function and postoperative acute kidney injury (AKI). From April 2009 to December 2012, we prospectively enrolled 3245 cardiac surgery patients of our hospital. The primary endpoints included survival rates and the secondary endpoint was the incidence of progressive chronic kidney disease (CKD) in a follow-up period of 2 years. Acute kidney injury was staged by KDIGO classification. Progressive CKD was defined as GFR ≤ 30 mL/min/1.73 m or end-stage renal disease (ESRD) (starting renal replacement therapy or renal transplantation).The AKI incidence was 39.9% (n = 1295). The 1 and 2 year overall survival (OS) rates of AKI patients were significantly lower than that for non-AKI patients (85.9% and 82.3% vs 98.1% and 93.7%, P < 0.001), even after complete recovery of renal function during 2 years after intervention (P < 0.001). The 2-year overall survival (OS) rates of patients with AKI stage 1, 2, and 3 were 89.9%, 78.6%, and 61.4% (P < 0.001), respectively. Multivariate Cox regression analysis of factors for 2-year survival rates revealed that besides age (P < 0.001), chronic cardiac failure (P < 0.001), diabetes (P < 0.001), cardiopulmonary bypass time (P < 0.01), and length of intensive care unit (ICU) stay (P = 0.004), AKI was a significant risk factor for reducing 2-year survival rates even after complete recovery of renal function (P < 0.001). The accumulated progressive CKD prevalence was significantly higher in AKI than in non-AKI patients (6.8% vs 0.2%, P < 0.001) in the 2 years after surgery. Even with complete recovery of renal function at discharge, AKI was still a risk factor for accumulated progressive CKD (RR 1.92, 95% CI 1.37-2.69).The 2-year mortality and progressive CKD incidence even after complete recovery of renal function were significantly increased in cardiac surgery patients with postoperative AKI.

A novel contrast-induced acute kidney injury model based on the 5/6-nephrectomy rat and nephrotoxicological evaluation of iohexol and iodixanol in vivo.

Contrast-induced acute kidney injury (CI-AKI) is a serious complication in patients after administration of iodinated contrast media. Proper animal models of CI-AKI can help understand the mechanisms involved and prevent the disorder. We used the 5/6-nephrectomized (NE) rat to develop a CI-AKI model and to evaluate differences in the toxic effects on the kidney between iohexol and iodixanol. We found that six weeks after ablative surgery was the preferred time to induce CI-AKI. We compared multiple pretreatment plans and found that dehydration for 48 hours before iodixanol (320, 10 mL/kg) administration was optimal to induce CI-AKI in the 5/6 NE rats. Compared with iodixanol, iohexol induced a significantly greater reduction in renal function, severe renal tissue damage, intrarenal hypoxia, and apoptotic tubular cells. Iohexol and iodixanol resulted in similarly marked increases in levels of inflammation and oxidative stress. In summary, the 5/6 NE rat combined with dehydration for 48 hours is a useful pretreatment to establish a novel and reliable CI-AKI model. Iohexol induced more severe CI-AKI than iodixanol in this model.

Rapamycin reduces renal hypoxia, interstitial inflammation and fibrosis in a rat model of unilateral ureteral obstruction.

PURPOSE: The purpose of this study was to explore effects of rapamycin on renal hypoxia, interstitial inflammation and fibrosis, and the expression of transforming growth factor ß1 (TGF-ß1), vascular endothelial growth factor (VEGF), Flk-1 and Flt-1 in a rat model of unilateral ureteral obstruction (UUO). METHODS: Male Sprague-Dawley rats (n=36) were randomly divided into three groups (n=12 per group): sham surgery, UUO and UUO plus rapamycin (0.2 mg/kg/d). Serum creatinine (Scr), blood urea nitrogen, uric acid, triglycerides, cholesterol and 24-h urine protein levels were measured. The extent of interstitial fibrosis was determined by Masson's trichrome staining. ED-1 positive macrophages, type III collagen, hypoxia, TGF-1, VEGF, Flk-1, and Flt-1 mRNA and protein expressions were detected using immunohistochemical staining, real-time PCR and Western blot. RESULTS: UUO induced an elevation in Scr, renal hypoxia, inflammation, interstitial fibrosis, TGF-ß1, VEGF, Flk-1, and Flt-1 mRNA and protein expression levels (P < 0.05). Rapamycin alleviated the UUO-induced renal hypoxia, infiltration of inflammatory cells and tubulointerstitial fibrosis (at days 3 and 7). Rapamycin also down-regulated the UUO-induced elevated expression levels of TGF-ß1 and Flt-1 mRNA and protein (P < 0.05). Rapamycin decreased VEGF mRNA and protein expression at day 3, and increased Flk-1 mRNA and protein expression at day 7, compared with the UUO group (P < 0.05). CONCLUSION: Rapamycin shows beneficial effects by reducing UUO-induced renal hypoxia, inflammation and tubulointerstitial fibrosis.

Efficacy and safety of Abelmoschus manihot for primary glomerular disease: a prospective, multicenter randomized controlled clinical trial.

BACKGROUND: Abelmoschus manihot, a single medicament of traditional Chinese medicine, has been widely used to treat kidney disease. This is the first randomized controlled clinical trial to assess its efficacy and safety in patients with primary glomerular disease. STUDY DESIGN: Prospective, open-label, multicenter, randomized, controlled, clinical trial. SETTING & PARTICIPANTS: From May 2010 to October 2011, a total of 417 patients with biopsy-proven primary glomerular disease from 26 hospitals participated in the study. INTERVENTIONS: A manihot in the form of a huangkui capsule, 2.5 g, 3 times per day; losartan potassium, 50mg/d; or combined treatment, a huangkui capsule at 2.5 g 3 times per day, was combined with losartan potassium, 50mg/d. The duration of intervention was 24 weeks. OUTCOMES & MEASUREMENTS: The primary outcome was change in 24-hour proteinuria from baseline after treatment. Change in estimated glomerular filtration rate (eGFR) from baseline after treatment was a secondary outcome. The 24-hour proteinuria was measured every 4 weeks and eGFR was measured at 0, 4, 12, and 24 weeks. RESULTS: Mean baseline urine protein excretion was 1,045, 1,084, and 1,073 mg/d in the A manihot, losartan, and combined groups, respectively, and mean eGFR was 108, 106, and 106 mL/min/1.73 m2, respectively. After 24 weeks of treatment, mean changes in proteinuria were protein excretion of -508, -376, and -545 mg/d, respectively (P=0.003 for A manihot vs losartan and P<0.001 for the combined treatment vs losartan). Mean eGFR did not change significantly. The incidence of adverse reactions was not different among the 3 groups (P>0.05), and there were no severe adverse events in any group. LIMITATIONS: Results cannot be generalized to those with nephrotic syndrome or reduced eGFR. CONCLUSIONS: A manihot is a promising therapy for patients with primary kidney disease (chronic kidney disease stages 1-2) with moderate proteinuria.

[Effects of hypoxic preconditioning on the migration of bone marrow derived mesenchymal stem cells].

OBJECTIVE: To explore the effects and probable mechanism of CoCl2-induced hypoxic preconditioning on the migration of bone marrow derived mesenchymal stem cells (BMSC). METHODS: BMSC were cultured by whole bone marrow adherence and identified by surface markers (CD29, CD90 and CD45) with flow cytometry (FCM). The methods of 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and FCM were applied to establish the model of CoCl2-induced hypoxic preconditioning. The migratory capacity of BMSC with hypoxic preconditioning was analyzed by the assays of scratch wound healing and transwell migration. The protein and mRNA expressions of HIF-1α and CXCR4 of BMSC were detected by Western blot and real-time polymerase chain reaction (PCR). After silencing HIF-1α by siRNA technique and blocking CXCR4 by its antagonist AMD3100, the changes of migratory capacity of BMSC were also tested. RESULTS: Cultured BMSC were uniformly positive for CD29 and CD90 and negative for CD 45. According to the results of MTT and FCM, 200 µmol/L CoCl2 and 24 h culture time was the ideal hypoxic preconditioning model of BMSC. The migratory capacity of BMSC in hypoxic preconditioning group was higher than the one in control group (scratch wound healing assay: (0.396 ± 0.018) mm vs (0.200 ± 0.011) mm, transwell migration assay: 21.0 ± 4.5 vs 8.5 ± 1.7, both P < 0.05). The protein and mRNA levels of HIF-1α and CXCR4 of BMSC in hypoxic preconditioning group were significantly higher than in control group. After silencing HIF-1α or blocking CXCR4 by AMD3100, the migratory capacity of BMSC in hypoxic preconditioning group decreased and had no difference with the control group. CONCLUSIONS: Hypoxic preconditioning may enhance the migratory capacity of BMSC in vitro. And it is partially attributable to the up-regulation of HIF-1α/CXCR4 axis after preconditioning.

[The risk factors and prognosis of acute kidney injury after cardiac surgery: a prospective cohort study of 4007 cases].

OBJECTIVE: To investigate the risk factors and prognosis influential factors of acute kidney injury (AKI) after cardiac surgery. METHODS: The clinical data of patients who were hospitalized and underwent cardiac surgery from April 2009 to May 2011 were collected prospectively. Demographic characteristics, types of surgeries, preoperative renal function, pre- and intra-operative conditions and clinical outcomes, etc were recorded. RESULTS: A total of 4007 patients underwent cardiac surgery were recruited. The overall incidence of AKI was 31.2% (1250/4007). The incidence of AKI requiring renal replacement treatment (AKI-RRT) was 2.6% (104/4007). The overall hospital mortality was 1.9% (77/4007), and was significantly higher in AKI group than in non-AKI group (5.4% vs 0.3%, P < 0.01). The hospital mortality of AKI-RRT group was 36.5% (38/104). Grouped by type of surgery, cardiac transplantation had the highest AKI incidence (73.0%) and highest in-hospital mortality (18.9%), followed by coronary artery bypass grafting (CABG) combined with valve surgery (AKI incidence 57.8%, in-hospital mortality 6.1%) and aneurysm surgery (AKI incidence 52.0%, in-hospital mortality 5.5%). Multivariate logistic regression analysis showed that man, age, BMI, hypertension, chronic heart failure, pre-operative serum creatinine (SCr) > 106.0 µmol/L, intra-operative cardiopulmonary bypass time, intra-operative hypotension and aneurysm surgery were the risk factors of AKI after cardiac surgery. Multivariate logistic regression analysis showed that pre-operative SCr > 106.0 µmol/L and intra-operative hypotension were independent risk factors of renal recovery after cardiac surgery while recovery of urine output was the favorable factor. CONCLUSIONS: Cardiac surgery usually induces high AKI incidence and poor prognosis, which closely associated with many risk factors in peri-operative stage. The incidence of AKI is related to a number of perioperative risk factors. Heart transplantation, aneurysm surgery, CABG combined valve surgery are high risk surgeries.

[Goal-directed renal replacement therapy for acute kidney injury after cardiac surgery].

OBJECTIVE: To compare the efficacy and safety of goal-directed renal replacement therapy(GDRRT) and daily high volume hemofiltration (dHVHF) in the treatment of acute kidney injury (AKI) after cardiac surgery. METHODS: Clinical data from 128 patients received either GDRRT (n = 64) or dHVHF (n = 64) for AKI after cardiac surgery were analyzed retrospectively. parameters examined included: urea nitrogen, serum creatinine (SCr, before and after treatment), heart rate, mean artery pressure (MAp, recorded within 72 hours after the initiation of renal replacement therapy). The hospital mortality, day-28 mortality, renal function recovery rate, and the incidence of adverse events in the two groups were also compared. RESULTS: The hospital mortality was 43.75% for both GDRRT and dHVHF treated patients (group). The day-28 mortality in GDRRT group were slightly lower, but the difference was not significant (43.75% vs. 57.81%, P = 0.055). Also no significant difference was found between the two groups in hospital stay. The patients received dHVHF had longer intensive care unit (ICU) stay (hours) and duration of mechanical ventilation (days) as compared to the patients received GDRRT [356.5 (176.3, 554.6) vs. 238.3 (119.6, 440.9), P = 0.023; 8.0 (5.0, 16.0) vs. 6.0 (3.0, 13.5), P = 0.042]. The logistic regression analyses showed that complete renal function recovery rate in GDRRT group was significantly higher (39.1% vs. 18.8%, P < 0.01). The partial renal function recovery rate in GDRRT group was slightly lower but not statistically different from dHVHF group (3.1% vs. 9.4%, P > 0.05). In dHVHF group, the maximum SCr during the treatment, and the SCr before discharge were both significantly higher than GDRRT group (µmol/L: SCr maximum 559.0 ± 236.0 vs. 440.4 ± 192.0, SCr before discharge 381.4 ± 267.0 vs. 271.2 ± 164.4, both P < 0.01). No significant difference was found between the two groups in incidence of hypotension (35.9% vs. 37.5%) and MAP (mm Hg, 1 mm Hg=0.133 kPa, 82 ± 13 vs. 81 ± 15) 72 hours into the therapy (both P > 0.05). The incidence of tachycardia, and incidence of blood coagulation were both higher in dHVHF group (78.1% vs. 59.4%, 35.9% vs. 20.3%, both P < 0.05). However, the hospitalization expense (thousand yuan) was significantly higher for dHVHF group (15.00 ± 2.80 vs. 9.85 ± 3.00, P < 0.01). CONCLUSION: For patients with post-cardiac surgery AKI, GDRRT and dHVHF are very similar in terms of short-term survival rate and safety. But GDRRT is superior for renal function recovery and cost saving.

[Analysis of drug-induced acute renal failure in Shanghai].

OBJECTIVE: To investigate the incidence and prognosis of drug-induced acute renal failure (ARF) in Shanghai. METHODS: The registration forms of ARF patients admitted in 17 hospitals of and over the middle class in Shanghai from January 1, 2004 to December 31, 2006 were screened prospectively. The data, such as epidemiology, survival, mortality, and morbidity were analyzed. RESULTS: 347 of the 1200 ARF patients (28.9%), 224 males and 123 females, aged (58+/-20), suffered from drug-induced ARF. 51.0% of the 347 patients were older than 60. 60.2% of the drug-induced ARF in the non-surgical departments were community-acquired, while 55.7% of the drug-induced ARF in the surgical departments were hospital-acquired. Among the non-surgical departments, the incidence of hospital-acquired drug-induced ARF was the lowest in the department of nephrology (9.5%), while higher in the departments of hematology, cardiology, and neurology, and among the surgical departments, it was the lowest in department of renal surgery, while higher in the departments of liver transplantation, neurosurgery, and cardiovascular surgery. The most common complication was chronic kidney disease (CKD) (n=69, 19.9%), followed by cerebrovascular disease (n=59, 17.0%), diabetes mellitus (n=43, 12.4%), and hypertension (n=41, 11.8%). Renal biopsy showed acute tubular necrosis (18, 37.5%), acute interstitial nephritis (11, 22.9%), and acute infectious tubulo-interstitial nephritis (6, 12.5%). Antibiotics (47.8%) were the head causes of drug-induced ARF, especially aminoglycoside (17.0%) and cephalosporins (12.7%), followed by diuretics (22.2%) and radiocontrasts (13.3%). 22.5% of the drug-induced ARF patients had used two or more drugs. 119 patients (34.3%) needed renal replacement treatment. 100 of the 347 patients (28.8%) died. 188 of the surviving patients (54.2%) had their renal function recovered completely, the renal function of 42 of them (12.1%) was recovered partially, and 17 of then (4.9%) required dialysis when discharged. CONCLUSION: Drug-induced ARF is common with higher incidence in the patients with complications. Antibiotics, diuretic agents, and contrast medium are the main causes.

Renal protection by delayed ischaemic preconditioning is associated with inhibition of the inflammatory response and NF-kappaB activation.

Brief and sublethal ischaemia renders an organ tolerant to subsequent prolonged ischaemia, which is called ischaemic preconditioning (IPC). In regard to the beneficial effects and endogenous mechanisms of renal delayed IPC, few data are available. In this study, we aim at determining reno-protective effects of delayed IPC against ischaemia-reperfusion (I/R) injury, and illustrating whether these effects are associated with suppressing inflammation and nuclear factor-kappaB (NF-kappaB) activation. I/R injury was induced by clamping both renal pedicles for 40 min, followed by 24 h of reperfusion. The rats were subjected to ischaemia for 20 min (preconditioning) or sham surgery (non- preconditioning) at day 4 before I/R. Functional and morphological parameters were evaluated at 24 h after reperfusion. At the same time, macrophage (ED-1(+)) infiltration, and the expression of intercellular adhesion molecule-1 (ICAM-1) and tumor necrosis factor-alpha (TNF-alpha) were assessed by immunohistochemistry. Moreover, I kappa B-alpha degradation and NF-kappaB/DNA binding activity were analyzed. Compared with rats exposed to I/R injury, preconditioned rats had a significant decrease in levels of serum creatinine (Scr, 384.3 +/- 21.8 micromol/L vs. 52.5 +/- 21.7 micromol/L; p<0.001), blood urea nitrogen (BUN, 40.4 +/- 2.7 mmol/L vs. 15.9 +/- 4.2 mmol/L; p<0.001) and serum aspartate aminotransferase (AST, 486.7 +/- 58.6 IU/L vs. 267.3 +/- 43.9 IU/L; p<0.001). Parallel to the above changes, preconditioned rats preserved structural integrity and decreased tubulointerstitial damage scores (3.4 +/- 0.3 vs. 0.2 +/- 0.05; p<0.001) and ED-1(+) cell infiltration (25.3 +/- 3.5 vs. 6.2 +/- 1.2 cells/HPF, p<0.01). Furthermore, our results showed that the expression of ICAM-1 and TNF-alpha, the degree of I kappa B-alpha degradation, and NF-kappaB/DNA binding activity were reduced by IPC. Taken together, our results demonstrated that delayed IPC offered both functional and histological protection, which may be related to suppression of inflammation in preconditioned kidneys.

In vivo transfection of NF-kappaB decoy oligodeoxynucleotides attenuate renal ischemia/reperfusion injury in rats.

BACKGROUND: Ischemic acute renal failure (ARF) is a common and often fatal condition characterized by tubular epithelial cell necrosis and marked monocyte infiltration. Inflammatory mechanisms, including cell adhesion, cell infiltration, and cytokine production, are involved. These processes are thought to be directly or indirectly regulated by nuclear factor kappaB (NF-kappaB). Targeted of NF-kappaB might ameliorate ischemia/reperfusion (I/R) injury by inhibiting the production of genes that involved in ischemic ARF. The objective of the present study was to evaluate the effect of NF-kappaB decoy oligodeoxynucleotides (ODN) in experimental rat ischemic ARF. METHODS: Ischemic ARF was induced by left renal artery clamping for 60 minutes, while the right kidney was being removed in female Sprague-Dawley rats. The effect of cationic liposome-protamine-NF-kappaB decoy ODN was evaluated after infusion into the kidney via the renal artery before clamping. After 24 hours of reperfusion, we then assessed morphologic and functional parameters, NF-kappaB/DNA binding activity, monocyte/macrophage (M/MPhi) infiltration, and gene expression in I/R kidney. RESULTS: After 24 hours of reperfusion, compared with sham-operated animals, serum creatinine and blood urea nitrogen (BUN) levels in ischemic ARF animals were increased about 10-fold and fivefold respectively. (255.67 +/- 34.48 micromol/L vs. 25.33 +/- 2.23 micromol/L and 43.47 +/- 5.50 mmol/L vs. 8.45 +/- 0.43 mmol/L, P < 0.001), NF-kappaB/DNA binding activity was markedly elevated [median value was 1.75 vs. 0.15 relative density unit (RDU), P < 0.005]. NF-kappaB decoy ODN treatment reduced the elevation of serum creatinine level by 70% (79.17 +/- 8.64 micromol/L vs. 255.67 +/- 34.48 micromol/L, P < 0.01), BUN level by 40% (28.33 +/- 4.86 mmol/L vs. 43.47 +/- 5.50 mmol/L, P= NS), and almost abolished the NF-kappaB activation compared with levels observed in sham-operated rats (median value was 0.25 vs. 1.9 RDU, P < 0.005). Furthermore, NF-kappaB decoy ODN pretreatment prevented the occurrence of tubular necrosis and reduced the renal tubular damage scores markedly (1.85 +/- 0.06 vs. 3.63 +/- 0.06 scores, P < 0.01). In addition, M/MPhi infiltration was obviously suppressed (9.77 +/- 1.19 cells/hpf vs. 29.22 +/- 1.94 cells/hpf, P < 0.01), Moreover, results of reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry showed the up-regulation of monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1) was greatly decreased, inducible nitric oxide synthase (iNOS) and endothelin-1 (ET-1) expression were also reduced, approaching levels observed in sham-operated animals. The data suggest that NF-kappaB decoy ODN treatment protects renal tissue from the effects of I/R injury and thus reduces the severity of ARF. CONCLUSION: These experiments demonstrated that NF-kappaB plays a critical role in renal I/R injury by reducing a series of inflammatory genes. NF-kappaB decoy ODN treatment reduces the renal dysfunction and damage associated with ischemic ARF. Therefore, in vivo transfection of NF-kappaB decoy ODN provides a new therapeutic strategy for ischemic ARF.