The impact of stopping inhibitors of the renin-angiotensin system in patients with advanced chronic kidney disease.

BACKGROUND: Inhibition of the renin-angiotensin-aldosterone system (RAAS) has shown to slow chronic kidney disease (CKD) progression. This is most notable at the earlier stages of diabetic and proteinuric nephropathies. Objective. Here, we observed the impact of discontinuation of angiotensin converting enzyme inhibitors (ACEi)/angiotensin receptors blockers (ARB) in patients with advanced kidney disease. METHODS: 52 patients (21 females and 31 males) with advanced CKD (stages 4 and 5), who attended our low clearance clinic (LCC) in preparation for renal replacement therapy (RRT). Mean age was 73.3 ± 1.8 years with an estimated glomerular filtration rate (eGFR) of 16.38 ± 1 ml/min/1.73 m(2). Baseline urine protein:creatinine ratio (PCR) was 77 ± 20 mg/mmol. 46% suffered from diabetes mellitus. Patients were followed for at least 12 months before and after ACEi/ARB were stopped. RESULTS: 12 months after discontinuation of ACEi/ARB eGFR increased significantly to 26.6 ± 2.2 ml/min/ 1.73 m(2) (p = 0.0001). 61.5% of patients had more than a 25% increase in eGFR, whilst 36.5% had an increase exceeding 50%. There was a significant decline in the eGFR slope -0.39 ± 0.07 in the 12 months preceding discontinuation. The negative slope was reversed +0.48 ± 0.1 (p = 0.0001). Mean arterial blood pressure (MAP) increased from 90 ± 1.8 mmHg to 94 ± 1.3 mmHg (p = 0.02), however ≥50% of patients remained within target. Overall proteinuria was not affected (PCR before = 77 ± 20 and after = 121.6 ± 33.6 mg/mmol). CONCLUSION: Discontinuation of ACEi/ARB has undoubtedly delayed the onset of RRT in the majority of those studied. This observation may justify a rethink of our approach to the inhibition of the RAAS in patients with advanced CKD who are nearing the start of RRT.

Do changes in transglutaminase activity alter latent transforming growth factor beta activation in experimental diabetic nephropathy?

BACKGROUND: Diabetic nephropathy is the leading cause of end-stage kidney failure worldwide. It is characterized by excessive extracellular matrix accumulation. Transforming growth factor beta 1 (TGF-ß1) is a fibrogenic cytokine playing a major role in the healing process and scarring by regulating extracellular matrix turnover, cell proliferation and epithelial mesanchymal transdifferentiation. Newly synthesized TGF-ß is released as a latent, biologically inactive complex. The cross-linking of the large latent TGF-ß to the extracellular matrix by transglutaminase 2 (TG2) is one of the key mechanisms of recruitment and activation of this cytokine. TG2 is an enzyme catalyzing an acyl transfer reaction leading to the formation of a stable ε(γ-glutamyl)-lysine cross-link between peptides. METHODS: To investigate if changes in TG activity can modulate TGF-ß1 activation, we used the mink lung cell bioassay to assess TGF-ß activity in the streptozotocin model of diabetic nephropathy treated with TG inhibitor NTU281 and in TG2 overexpressing opossum kidney (OK) proximal tubular epithelial cells. RESULTS: Application of the site-directed TG inhibitor NTU281 caused a 25% reduction in kidney levels of active TGF-ß1. Specific upregulation of TG2 in OK proximal tubular epithelial cells increased latent TGF-ß recruitment and activation by 20.7% and 19.7%, respectively, in co-cultures with latent TGF-ß binding protein producing fibroblasts. CONCLUSIONS: Regulation of TG2 directly influences the level of active TGF-ß1, and thus, TG inhibition may exert a renoprotective effect by targeting not only a direct extracellular matrix deposition but also TGF-ß1 activation and recruitment.

Transglutaminase inhibition ameliorates experimental diabetic nephropathy.

Diabetic nephropathy is characterized by excessive extracellular matrix accumulation resulting in renal scarring and end-stage renal disease. Previous studies have suggested that transglutaminase type 2, by formation of its protein crosslink product epsilon-(gamma-glutamyl)lysine, alters extracellular matrix homeostasis, causing basement membrane thickening and expansion of the mesangium and interstitium. To determine whether transglutaminase inhibition can slow the progression of chronic experimental diabetic nephropathy over an extended treatment period, the inhibitor NTU281 was given to uninephrectomized streptozotocin-induced diabetic rats for up to 8 months. Effective transglutaminase inhibition significantly reversed the increased serum creatinine and albuminuria in the diabetic rats. These improvements were accompanied by a fivefold decrease in glomerulosclerosis and a sixfold reduction in tubulointerstitial scarring. This was associated with reductions in collagen IV accumulation by 4 months, along with reductions in collagens I and III by 8 months. This inhibition also decreased the number of myofibroblasts, suggesting that tissue transglutaminase may play a role in myofibroblast transformation. Our study suggests that transglutaminase inhibition ameliorates the progression of experimental diabetic nephropathy and can be considered for clinical application.

High prevalence of microalbuminuria in the overweight and obese population: data from a UK population screening programme.

BACKGROUND: Microalbuminuria (MA) is associated with increased risk of cardiovascular and possibly chronic kidney disease (CKD). Obesity has been linked to MA, though the prevalence of MA in overweight groups is not well documented. This population study with an overrepresentation of individuals with BMI >25 (calculated as kg/m2) investigates the prevalence of MA in different BMI categories, and the relationship between MA and BMI. METHODS: Data from two cross-sectional epidemiological studies in the City of Sheffield were combined to produce a cohort of non-diabetic, non-CKD subjects over the age of 18. The first study, Kidney Evaluation and Awareness Programme in Sheffield (KEAPS), is a general population screening programme, whilst Kidney Evaluation in Overweight Population in Sheffield (KEOPS) is a screening programme specifically for individuals with BMI >25. RESULTS: The combined database had 1,179 subjects eligible for analysis after applying exclusion criteria. The prevalence of MA in subjects with BMI <25 was 3.1% compared to 12.1% in those with BMI 25-30 and 27.2% in obese subjects with BMI >30 (p < 0.001). The prevalence of MA increased exponentially with the BMI category. BMI is a predictor of MA in logistic regression analyses in the population as a whole, males, females, younger and older age categories, and higher BMI groups (above median and upper tertile). The effect of BMI persists after adjusting for confounding variables. The relative risk for having urine albumin concentration >20 mg/l is 8.0 (95% CI 3.8-16.8, p < 0.0001) if BMI is above the 80th percentile (BMI >27.2). CONCLUSION: The prevalence of MA increases with increasing BMI in the population of Sheffield. The risk of having MA increases exponentially with BMI. The significance of the high prevalence of MA in overweight and obese individuals should be investigated longitudinally.

Influence of obesity on progression of non-diabetic chronic kidney disease: a retrospective cohort study.

BACKGROUND: There is increasing awareness of the impact of obesity on chronic diseases including chronic kidney disease (CKD). Until recently, a limited number of epidemiologic studies have examined the association between obesity and CKD. We conducted a retrospective cohort study to evaluate whether obesity impacts on the rate of non-diabetic CKD progression. METHODS: The medical records of 125 non-diabetic CKD patients in the Sheffield Kidney Institute, Sheffield, UK, who have been followed-up for around 10 years, were reviewed. Various socio-demographic, clinical and biochemical parameters were retrospectively collected from the patients' database. Participants were categorized into normal weight, overweight and obese groups. Multivariate regression analysis was used for modelling with estimated glomerular filtration rate (eGFR) reduction per year as the dependent variable to evaluate the impact of obesity (BMI) on CKD progression. RESULTS: Patients studied were mostly CKD stage 3 with a mean GFR of 36.2 ml/min/1.73 m(2) for the control group and 44.3 ml/min/1.73 m(2) for those who were overweight or obese. Baseline diastolic and mean arterial blood pressure were significantly higher in overweight than normal weight CKD patients (p = 0.009 and p = 0.014 respectively). On follow-up, systolic, diastolic and mean arterial blood pressure were significantly higher in overweight (p = 0.03, p = 0.005 and p = 0.003, respectively) and obese (p = 0.008, p = 0.022 and p = 0.003, respectively) compared to normal weight CKD patients. Mean follow-up triglycerides level was significantly higher in obese than normal weight patients (p = 0.042). The frequency of CKD progression based on eGFR fall per year (>1 ml/min/1.73 m(2)/year) was 62.5% in overweight and 79.5% in obese compared to 44.7% in normal weight CKD patients (p = 0.007). However, no significant difference in the rate of progression (fall of eGFR ml/min/1.73 m(2)/year) was observed between the three groups. On multivariate regression analysis, adjusted for other covariates (age, BP and proteinuria), baseline BMI was an independent predictor of CKD progression (fall in eGFR, ml/min/1.73 m(2)/year) (R(2) = 0.122 and p < 0.001). Percentage changes in BMI over the observation period did not affect the rate of eGFR decline. Young age also predicted a faster CKD progression. CONCLUSIONS: Baseline BMI and young age are strongly and independently associated with faster CKD progression based on the annual rate of eGFR fall. Prospective studies to investigate the relationship between BMI and CKD and its complications are warranted.

Reduction of ischemia-reperfusion injury in the rat kidney by FTY720, a synthetic derivative of sphingosine.

BACKGROUND: The current shortage of organ donors has led many centers to use marginal and nonheart-beating donors (NHBDs). Recent research has implicated the infiltration of lymphocytes as an important mediator of ischemia-reperfusion injury (IRI). FTY720 is an immunosuppressant that promotes lymphocyte sequestration into lymph nodes. The purpose of this study was to examine the potential for FTY720 to abrogate IRI when subjected to increasing ischemic times. METHODS: Male Sprague-Dawley rats underwent bilateral flank incision with removal of the right kidney and clamping of the left hilum. Groups were divided into ischemia times of 45, 55, and 65min; each group was further divided into a control group (IRI only), IRI+FTY720 (1 mg/kg/d), and IRI+cyclosporine (15 mg/kg/d), n=4 per group. RESULTS: Thre days after 45 min of ischemia, serum creatinine in the ischemia only (477+/-37 micromol/L) and cyclosporine groups (698+/-32 micromol/L) was significantly increased compared with the FTY720-treated animals (194+/-66 micromol/L). The beneficial effect of FTY720 was also observed at 55 and 65 min; indeed, FTY720-treated animals demonstrated signs of recovery from 65 min of ischemia whereas control and cyclosporine-treated animals required sacrifice between days 3 and 5. Treatment with FTY720 reduced renal damage assessed histologically and also reduced apoptosis and increased cell proliferation. CONCLUSION: Treatment with FTY720 reduced IRI and prevented unrecoverable acute renal failure after significant ischemic injury. This study suggests that FTY720 may help improve the quality of grafts from NHBD and marginal donors by abrogating the IRI insult.

Immunosuppressive treatment of idiopathic focal segmental glomerulosclerosis: a five-year follow-up study.

BACKGROUND/AIMS: Focal segmental glomerulosclerosis (FSGS) is a common type of glomerular disease that can lead to chronic renal failure. Various therapeutic regimens have been used in nephrotic FSGS patients. The effect of treatment with prednisolone alone or its combination with azathioprine and cyclosporin and parameters related to a poor outcome are studied. METHODS: Fifty-one patients with idiopathic FSGS and a follow-up period of 5 years were included. Twenty-five were treated with prednisolone alone (1 mg/kg BW/day) or combination of prednisolone (0.5 mg/kg BW/day) with azathioprine (2 mg/kg BW/day) or cyclosporine (3 mg/kg BW/day) in gradually reduced doses whereas 26 patients received no immunosuppressive drugs. Lower prednisolone dose regimens were used as initial treatment in obese, borderline diabetics or patients with bone disease. The clinical course was estimated using the end-points of 50% or doubling of baseline serum creatinine and/or end-stage renal failure. The contribution of clinical and histological parameters in the clinical outcome was estimated by univariate and multivariate analyses. RESULTS: Increase of baseline serum creatinine by 50% during the follow-up period was observed in 2 treated and 9 untreated patients (8% vs. 35%, p = 0.03) whereas doubling of serum creatinine in 2 and 5 patients respectively (8% vs. 19%, p = NS). End-stage renal failure developed in 4 of 51 patients (8%), 2 treated and 2 untreated (p = NS). Parameters related to a poor outcome were baseline serum creatinine and severity of glomerulosclerosis (multivariate analysis OR = 1.08, p = 0.01). Most of patients (68%) who reached end-points had persistent nephrotic syndrome during the follow-up. Remission of nephrotic syndrome was observed more frequently among treated (75 vs. 30.7%, p = 0.05). Prednisolone alone was followed by remission of nephrotic syndrome in 62.5% whereas combination of lower prednisolone dose with azathioprine and cyclosporin in 80 and 85.7% of patients. No serious side-effects were observed. CONCLUSION: This and previous studies suggest that steroid and/or immunosuppressive therapy have a role in amelioration of the clinical course and remission of nephrotic syndrome in patients with FSGS A combination of low predisolone dose with cyclosporine could be used as initial treatment in patients with higher risk for side-effects from the usual prednisolone dose.

The outcome of acute renal failure in the intensive care unit according to RIFLE: model application, sensitivity, and predictability.

BACKGROUND: The definition, classification, and choice of management of acute renal failure (ARF) in the setting of the intensive care unit (ICU) remain subjects of debate. To improve our approach to ARF in the ICU setting, we retrospectively applied the new classification of ARF put forward by the Acute Dialysis Quality Initiative group, RIFLE (acronym indicating Risk of renal failure, Injury to the kidney, Failure of kidney function, Loss of kidney function, and End-stage renal failure), to evaluate its sensitivity and specificity to predict renal and patient outcomes. METHODS: RIFLE classification was applied to 183 patients with ARF admitted to the ICU (2002 to 2003) at the Northern General Hospital, Sheffield, UK. Patients were divided into 4 groups according to percentage of decrease in glomerular filtration rate from baseline. The risk group included 60 patients; injury group, 56 patients; failure group, 43 patients; and control group, 24 patients. Demographic, biochemical, hematologic, clinical, and long-term health status were studied and compared in the 4 groups. An attempt was made to evaluate, by means of logistic regression analysis and receiver operator characteristic curve analysis, the predictive value of RIFLE classification for mortality in the ICU. RESULTS: The failure group showed the worst parameters with regard to Acute Physiology and Chronic Health Evaluation (APACHE) II score, pH, lowest and highest mean arterial pressures, and Glasgow Coma Scale (P < 0.001). Mortality rate in the ICU (1 month) was significantly greater in the failure group compared with all groups (32 of 43 patients [74.4%]; P < 0.001) and, again, 6-month mortality rate (37 of 43 patients [86%]; P < 0.001). Receiver operator characteristic curve analysis showed that Simplified Acute Physiology Score (SAPS) II was more sensitive than APACHE II score for prediction of patient death in the risk and injury groups compared with the failure and control groups (risk group: SAPS II, 0.8 +/- 0.06; P < 0.001; APACHE II, 0.63 +/- 0.07; P = 0.14; injury group: SAPS II, 0.76 +/- 0.08; P < 0.001; APACHE II, 0.72 +/- 0.07; P = 0.006). CONCLUSION: RIFLE classification can improve the ability of such older and established ICU scoring systems as APACHE II and SAPS II in predicting outcome of ICU patients with ARF.

Prevention of chronic kidney disease: a global challenge.

In view of the increasing number of patients requiring renal replacement therapy (RRT) every year worldwide, attention has focused over the last two decades on meeting the health care need of patients with end-stage renal failure (ESRF). More recently, increasing awareness of the growing burden of chronic kidney disease (CKD), with a large percentage of the population affected by early stages of CKD, has shifted attention and health care priority to the prevention and early detection of CKD. This article addresses issues related to general population as well as targeted screening, favoring the latter. It also examines some of the screening initiatives undertaken in both the developing and developed worlds. It also highlights the links between albuminuria, CKD, and cardiovascular disease (CVD) as an increasing number of studies identify albuminuria/proteinuria, as well as CKD as major markers of CVD. Finally, a brief review is included of primary and secondary intervention strategies for CKD and issues related to their implementation: manpower and funding.

Cyclosporine A sensitizes the kidney to tubulointerstitial fibrosis induced by renal warm ischemia.

BACKGROUND: Renal warm ischemic injury and immunosuppression with cyclosporin A (CsA) may contribute to chronic allograft nephropathy after cadaveric transplantation. This study establishes whether CsA can sensitize the kidney to injury and fibrosis induced by renal warm ischemia (RWI). METHODS: The left kidney of Sprague-Dawley rats was subjected to 30 min of warm ischemia and/or intraperitoneal CsA (15 mg/kg/d) for 30 days (n=6 per group). Renal injury and fibrosis were assessed histologically together with immunohistochemistry for collagen III, transforming growth factor (TGF)-beta1, ED1 (macrophage marker), and alpha-smooth muscle actin. Renal mRNAs for collagen III, TGF-beta 1, matrix metalloproteinase (MMP)-2, and tissue inhibitor of metalloproteinase-1 together with MMP enzyme activity were also determined. RESULTS: RWI or CsA alone produced only minor effects on renal injury and fibrosis. However, in CsA-treated rats, RWI produced a marked increase in tubulointerstitial fibrosis, as shown by the potentiation of collagen III and TGF-beta1 determined by immunochemistry and mRNA analysis. The up-regulation of tissue inhibitor of metalloproteinase-1 mRNA was associated with a decrease in MMP enzyme activity. In CsA-treated rats, RWI was also associated with an increase in inflammatory infiltrates, elevated immunostain for ED1 (indicating extensive macrophage influx), and elevated immunostain for alpha-smooth muscle actin (indicating myofibroblast activation). CONCLUSIONS: In the rat, CsA can sensitize the kidney to fibrosis induced by renal warm ischemia. In renal transplantation, when cadaveric donor kidneys have been subjected to a period of warm ischemia, CsA may be an inappropriate choice for immunosuppressive therapy.

Tissue transglutaminase: a mediator and predictor of chronic allograft nephropathy?

BACKGROUND: The precise mechanisms underlying the development of chronic allograft nephropathy (CAN) and the associated renal fibrosis remain uncertain. The protein-crosslinking enzyme, tissue transglutaminase (tTg), has recently been implicated in renal fibrosis. METHODS.: We investigated the involvement of tTg and its crosslink product, epsilon-(gamma-glutamyl) lysine, in 23 human kidney allografts during the early posttransplantation period and related these to changes of CAN that developed in 8 of them. Sequential biopsies were investigated using immunohistochemical, immunofluorescence, and in situ enzyme activity techniques. RESULTS: From implantation, tTg (+266%) and epsilon-(gamma-glutamyl) lysine crosslink (+256.3%) staining increased significantly (P <0.001) in a first renal biopsy performed within 3 months from transplantation. This was paralleled by elevated tTg in situ activity. The eight patients who developed CAN had further increases in immunostainable tTg (+197.2%, P <0.001) and epsilon-(gamma-glutamyl) lysine bonds (+465%, P <0.01) that correlated with interstitial fibrosis (r=0.843, P =0.009 and r=0.622, P =0.05, respectively). The staining for both was predominantly located within the mesangium and the renal interstitium. Both implantation and first biopsies showed tTg and epsilon-(gamma-glutamyl) lysine crosslinking levels in patients who developed CAN to be twice the levels of those with stable renal function. Cox regression analysis suggested the intensity of the early tTg staining was a better predictor of inferior allograft survival that other histologic markers (hazard ratio=4.48, P =0.04). CONCLUSIONS: tTg and epsilon-(gamma-glutamyl) lysine crosslink correlated with the initiation and progression of scarring on sequential biopsies from renal-allograft recipients who experienced CAN. Elevated tTg may offer an early predictor of the development of CAN, whereas tTg manipulation may be an attractive therapeutic target.

Stem cell factor and crescentic glomerulonephritis.

BACKGROUND: Numerous cells and cytokines have been implicated in the pathogenesis of crescentic glomerulonephritis (CGN). Recently, there has been growing awareness of the role of mast cells and their growth factor, stem cell factor (SCF), in the process of tissue inflammation and fibrosis. METHODS: In this study, renal biopsy specimens from 28 patients with a histopathologic diagnosis of CGN were evaluated immunohistochemically for the presence of mast cells, SCF, and its receptor (c-kit). In addition, CD34+ hematopoietic cells, monocytes (CD68+ cells), and myofibroblasts (alpha-smooth muscle actin-positive [alpha-SMA+] cells) were counted. Renal biopsy specimens from cadaveric kidney donors and kidneys removed for hypernephroma (n = 6) served as controls. Point counting of positive immunostaining for SCF, alpha-SMA, and collagens III and IV was undertaken. Glomerular and interstitial fibrosis (IF) scores were determined. RESULTS: Patients who developed progressive chronic kidney failure showed a significant increase in percentage of crescents, number of interstitial c-kit+ cells, and glomerular CD68+ cells compared with those with a favorable outcome. Analysis showed a significant elevation of tryptase+ mast cells in the interstitium of renal biopsy specimens of patients with CGN compared with controls. SCF and c-kit+ cells were found in glomeruli and interstitium, with occasional immunostaining of the crescent with SCF. Both glomerular and interstitial SCF immunostaining was significantly higher in biopsy specimens of patients compared with controls. Glomerular and interstitial SCF showed a significant positive correlation with 24-hour urinary protein level. There were a few CD34+ cells in both glomeruli and interstitium, but their numbers did not differ between patients and controls. Colocalization of CD34+ and c-kit+ was seen in some rounded interstitial and spindle-shaped cells. Number of interstitial mast cells proved to be a strong predictor of IF. Glomerular SCF correlated negatively with creatinine clearance and positively with glomerular CD68+ cells. Interstitial immunostainable SCF correlated positively with interstitial CD68+ cells and interstitial collagen III. On double antigen labeling, SCF was shown in the vicinity of alpha-SMA+ cells. CONCLUSION: These results show the potential involvement of mast cells and their growth factor SCF/c-kit in CGN.

Inhibitors directed towards caspase-1 and -3 are less effective than pan caspase inhibition in preventing renal proximal tubular cell apoptosis.

BACKGROUND: Uncontrolled apoptosis contributes to tubular cell deletion in renal scarring. Caspase-3 has a central role in the execution of apoptosis and may provide a target for regulating cell death. Here we evaluate three caspase inhibitors: B-D-FMK (pan caspase inhibitor), Z-DEVDFMK (predominantly Caspase-3 inhibitor) and Z-VAD-FMK (predominantly Caspase-1 and -3 inhibitor) to ameliorate apoptosis induced by cisplatin in rat proximal tubular (RPT) cells. METHODS: Caspase-3 activity (substrate cleavage assay) and protein (immunocytochemistry and Western blotting), apoptosis (Annexin V flow cytometry, in situend labelling of fragmented DNA, light/electron microscopy and DNA laddering) and cell survival (trypan blue exclusion and propidium iodide flow cytometry) were determined in RPT cells exposed to cisplatin with and without caspase inhibitors. RESULTS: Cisplatin induced a dose-dependent increase in Caspase-3 activity and 8-fold of increase in apoptosis (p < 0.01) when applied for 24 h at 100 microM. B-D-FMK (40 microM), Z-DEVD-FMK (15 microM) and Z-VAD-FMK (22 microM) almost completely inhibited the 25-fold increase in Caspase-3 activity and decreased apoptosis from 15.9 +/- 4.4 to 2.0 +/- 0.6% (p < 0.01), 15.0 +/- 2.2 and 15.0 +/- 2.2% respectively. DNA ladders were visible in cisplatin-treated cells, which disappeared following addition of B-D-FMK and decreased with Z-VAD-FMK and Z-DEVD-FMK. Cisplatin reduced cell survival to 61% by trypan blue exclusion. B-D-FMK and Z-VAD-FMK increased this to 87 and 75%, but Z-DEVD-FMK had no significant effect. CONCLUSIONS: Cisplatin causes an increase in RPT apoptosis that is associated with increased Caspase-3 activity. All caspase inhibitors were equally effective at reducing Caspase-3 activity, however the pan caspase inhibitor B-D-FMK was more effective at preventing apoptosis and increasing cell survival. Therefore, pan caspase inhibition offers the greatest potential for the prevention of renal tubular cell deletion by uncontrolled apoptosis.

Prednisolone and azathioprine in IgA nephropathy - a ten-year follow-up study.

BACKGROUND: Immunoglobulin A nephropathy (IgAN) is one of the most common primary glomerular diseases. Although its clinical course is usually benign, some patients develop end-stage renal failure (ESRF). The role of immunosuppressive drugs in the treatment of IgAN remains controversial. The effect of treatment with prednisolone and azathioprine and the clinical and histological parameters related to a poor outcome are examined retrospectively in this analysis. METHODS: Seventy-four patients with IgAN and a follow-up period of 10 years were included in this study. Forty-one were treated with prednisolone (initially 60 mg/day) and azathioprine (initially 2 mg/kg BW/day) in gradually reduced doses for 24 +/- 9 months, whereas 33 patients received no immunosuppressive drugs. The clinical course was estimated using the end-points of doubling of baseline serum creatinine and/or ESRF. The contribution of clinical and histological parameters in the clinical outcome was estimated by univariate and multivariate analyses. RESULTS: The overall clinical courses of both groups of patients showed a rather similar pattern. Doubling of serum baseline creatinine was observed in 9 of 41 treated (22%) and in 10 of 33 untreated (30%), whereas ESRF developed in 6 treated (15%) and 6 untreated patients (18%) (p = NS). However, treated patients with heavy proteinuria (>3 g/24 h) had a significantly better outcome compared to untreated (doubling of serum creatinine in 29 vs. 78% and ESRF in 17 vs. 55%, p < 0.05). Proteinuria (p < 0.01), mean blood pressure (p < 0.02), baseline serum creatinine (p = 0.02) and severity of interstitial myofibroblast expression (p = 0.02) were identified as independent risk factors related to a poor outcome by multivariate analysis. Side effects of treatment were not uncommon and observed in 10 (24%) patients. CONCLUSION: Treatment with prednisolone and azathioprine is beneficial in ameliorating the clinical course of a subset of IgAN patients with heavy proteinuria or impaired renal function. Patients with advanced renal failure and severe chronic histological lesions should not be treated by this regimen as no benefit is expected and there is a risk of side effects.

Cellular toxicity of catechin analogues containing gallate in opossum kidney proximal tubular (OK) cells.

A variety of catechins exist in green tea and Chinese rhubarb. It is also known that the green tea tannin mixture and its individual tannin components such as (-)-epicatechin 3-O-gallate (ECG) and (-)-epigallocatechin 3-O-gallate (EGCG) suppress renal failure in animals and inhibit the growth of mesangial cells. In addition, gallic acid (GA), a structural constituent of these catechins, induces apoptosis in tumor cell lines. However, the effects of catechins on renal tubular cells have not been investigated. In this experiment, the growth of opossum kidney proximal tubular (OK) cells was inhibited by GA (36.9 +/- 9.5%, p < 0.01) and EGCG (48.6 +/- 16.7%, p < 0.01) at 50 microM, and was almost completely inhibited by these compounds at concentrations over 100 microM. Furthermore, ECG inhibited the growth of OK cells at concentrations over 200 microM (52.6 +/- 16.5%, p < 0.01). The numbers of in situ end-labeled (ISEL) cells in cultures treated with GA at 25 and 50 microM, ECG at 100 and 200 microM, or EGCG at 25 microM were significantly less than those in the cultures treated with high-concentration EGCG (50 microM). In addition, exposure to 50 microM EGCG or 400 microM GA for 24 hr led to a significant increase in fragmented DNA, but ECG did not significantly induce DNA fragmentation compared to the control. These results suggest that EGCG induces mostly apoptosis in OK cells, but the cellular toxicity of GA involves both apoptosis and other mechanisms. Finally, ECG inhibits the growth largely via some mechanism other than apoptosis. This chemical-specific difference of cytotoxic pattern may be dependent on the combination of GA and basal catechin structures, or NADH oxidase (NOX) activity on the OK cell surface.

The effect of L-arginine on the progression of chronic renal scarring in remnant kidney.

OBJECTIVE: To investigate the effect of L-arginine (L-arg) on early compensatory renal growth (CRG), tubulointerstitial accumulation of extracellular matrix (ECM), long term survival rate and renal scarring in rats with 5/6 nephrectomy (SNx). METHODS: The experiment included four groups of rats (n = 5 each group): (1) Sham group, (2) SNx group, (3) SNx + L-arg group, and (4) Sham + L-arg group (L-arg 1% in drinking water). Parameters related with CRG and early tubulointerstitial expression of ECM and alpha smooth muscle actin (alphaSMA) were evaluated by immunohistochemistry at day 30. The survival rate and the extent of renal scarring in the rats were observed at day 120. RESULTS: L-arg significantly increased the early CRG of SNx rats as determined by the wet kidney weight (P < 0.05), total protein (P < 0.01), and DNA content (P < 0.001) of the remnant kidney. The cell proliferation in the tubulointerstitium as determined by immunostaining for proliferative cell nuclear antigen (PCNA) also markedly increased (P < 0.05). Furthermore, glomerular volume (Vg) in the SNx rats treated by L-arg increased 16% compared with that in the SNx group (P = 0.06). More specifically, L-arg significantly increased the interstitial immunostaining for collagen III, IV, and fibronectin (P < 0.05, 0.01, respectively), which were positively correlated with the increased expression of alpha-SMA (P < 0.001, respectively). In the long term experiment, L-arg significantly reduced the survival rate (P < 0.05) and increased the severity of renal scarring in the SNx rats (P < 0.05). CONCLUSION: This preliminary study suggested that early supplementation with L-arg might exacerbate the progression of renal scarring in rat remnant kidney.

Changes in matrix metalloproteinases and their inhibitors in kidney transplant recipients.

OBJECTIVES: Chronic allograft nephropathy remains one of the main causes of late graft loss after kidney transplant owing to multifactorial development of kidney scarring. Chronic allograft nephropathy is characterised by an excess accumulation of extracellular matrix. A key system regulating extracellular matrix homeostasis are matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases. This study sought to determine if a change in the matrix metalloproteinases/tissue inhibitors of matrix metalloproteinases system contributes to chronic allograft nephropathy-associated progressive kidney scarring. MATERIALS AND METHODS: Examination of sequential renal biopsies was done at implantation, acute rejection, and subsequent chronic allograft nephropathy. In situ localisation of matrix metalloproteinase activity was assessed with a high-resolution in situ zymography technique using gelatin and collagen 1 substrates. Matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases were localised using immunohistochemistry. RESULTS: In situ zymography showed over a 50% reduction in matrix metalloproteinase activity against both collagen 1 and gelatin substrates in chronic allograft nephropathy biopsies. A similar loss of matrix metalloproteinase activity was seen in the glomerular and tubulointerstitial compartments. Immunoreactive matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases were observed intracellularly in mesangial and tubular epithelial cells. Matrix metalloproteinases-1, -2, -3, and -9 were significantly reduced in acute rejection and later in chronic allograft nephropathy. However, glomerular matrix metalloproteinases 1 and 9 and tubulointerstitial matrix metalloproteinase-2 were reduced at implantation. Tissue inhibitors of matrix metalloproteinase-2 and -3 were elevated from implantation onwards. We were unable to stain reproducibly for tissue inhibitors of matrix metalloproteinase-1. CONCLUSIONS: Kidney scarring underlying chronic allograft nephropathy is associated with a reduction in matrix metalloproteinases activity that may be due to reduced expression of matrix metalloproteinases -1, -2, -3, and -9, and up-regulation of tissue inhibitors of matrix metalloproteinases -2 and -3. Some of these changes originate from implantation.

Cardiovascular disease on hemodialysis: predictors of atherosclerosis and survival.

Cardiovascular disease (CVD) is the leading cause of mortality in hemodialysis (HD) patients. This could not be explained by the known traditional CVD risk factors. In this study, we attempted to elucidate the factors influencing atherosclerosis, as measured by carotid artery intima-media thickness (IMT), in HD patients and their impact on cardiovascular mortality. A cohort of 50 patients started on HD was selected for this study. At baseline, IMT and the presence of atheromatous plaques were assessed. Plasma homocysteine (Hcy), malondialdehyde, total antioxidant capacity, von Willebrand factor, vitamins C, E, B(6), B(12), folate, and C-reactive protein (CRP) were also measured. Patients were followed up for 2 years to determine the impact of IMT and associated markers on mortality using survival analysis as well as Cox proportional hazard. At baseline, 40% of the patients had IMT>0.8 mm. They were older, had higher CRP (P<0.001), and lower serum albumin (P=0.03). Intima-media thickness >0.8 mm was associated with high calcium (risk ratio [RR]: 6.06; confidence interval [CI]: 0.75-12.25) and CRP (RR: 10.94 [CI: 2.56-46.74]). Fifteen patients (30%) died during the 2-year follow-up; the main cause of death was CVD (42%). The relative risk mortality was high with increased IMT (RR: 120.04 [CI: 4.18-3445.9]), Index of Coexistent Disease for CVD (RR: 4.04 [CI: 1.92-8.5]), and plasma Hcy (RR: 1.08 [CI: 1.02-1.13]). Markers of inflammation and increased serum calcium were significant predictors of increased carotid artery IMT. High IMT, Index of Coexistent Disease, and Hcy were associated with a high RR of all-cause mortality among a cohort of HD patients.