Severity Of Tubulointerstitial Fibrosis Research Articles

Urinary podocyte stress marker as a prognostic indicator for diabetic kidney disease

BackgroundDiabetic kidney diseases (DKD) is a the most common cause of end-stage kidney disease (ESKD) around the world. Previous studies suggest that urinary podocyte stress biomarker, e.g. podocin:nephrin mRNA ratio, is a surrogate marker of podocyte injury in non-diabetic kidney diseases.MethodWe studied 118 patients with biopsy-proved DKD and 13 non-diabetic controls. Their urinary mRNA levels of nephrin, podocin, and aquaporin-2 (AQP2) were quantified. Renal events, defined as death, dialysis, or 40% reduction in glomerular filtration rate, were determined at 12 months.ResultsUrinary podocin:nephrin mRNA ratio of DKD was significantly higher than the control group (p = 0.0019), while urinary nephrin:AQP2 or podocin:AQP2 ratios were not different between groups. In DKD, urinary podocin:nephrin mRNA ratio correlated with the severity of tubulointerstitial fibrosis (r = 0.254, p = 0.006). and was associated with the renal event-free survival in 12 months (unadjusted hazard ratio [HR], 1.523; 95% confidence interval [CI] 1.157–2.006; p = 0.003). After adjusting for clinical and pathological factors, urinary podocin:nephrin mRNA ratio have a trend to predict renal event-free survival (adjusted HR, 1.327; 95%CI 0.980–1.797; p = 0.067), but the result did not reach statistical significance.ConclusionUrinary podocin:nephrin mRNA ratio has a marginal prognostic value in biopsy-proven DKD. Further validation is required for DKD patients without kidney biopsy.

Serum levels of plasminogen activator urokinase receptor and cardiotrophin-like cytokine factor 1 in patients with nephrotic syndrome.

41 patients with chronic glomerulonephritis (CGN) were included in our study. 17 patients had FSGS, 7 patients had MCD, 5 patients had membranoproliferative glomerulonephritis (MPGN), 6 patients had IgA nephropathy, and 6 patients had membranous nephropathy (MN). The laboratory data were compared with the clinical and histological features of nephritis. Serum levels of plasminogen activator urokinase receptor (uPAR) and cardiotrophin-like cytokine factor 1 (CLCF-1)were measured by ELISA. The serum levels of uPAR were higher in FSGS patients before treatment than in patients with other morphological forms (MCD, IgA nephropathy, MN, and MPGN). The levels of uPAR in serum did not correlate with daily proteinuria, serum creatinine/eGFR, arterial hypertension, the number of sclerosed glomeruli, or tubulointerstitial fibrosis. No correlations were found between the levels of CLCF-1 in serum and creatinine levels/glomerular filtration rate, the percentage of sclerosed glomeruli, or the severity of tubulointerstitial fibrosis. There were no significant differences between the histological variants of nephritis. However, we found correlations between CLCF-1 levels and proteinuria and lipid levels. The data indicate an increase in the serum uPAR levels of FSGS before treatment. CLCF-1 levels in serum do not depend on histological forms of CGN, kidney function, or immunosuppressive treatment, but they correlate with proteinuria and serum lipids in patients with NS.

Role of MCP-1 in the development of tubulointerstitial fibrosis in patients with primary chronic glomerulonephritis

BACKGROUND. To date, the study of the factors involved in the glomerular-tubular pathological connections leading to damage to the tubulointerstitial tissue is one of the topical areas of nephrology. THE AIM: to study the effect of MCP-1 in the development of tubulointerstitial fibrosis as a factor in the irreversible progression of chronic renal failure. PATIENTS ANDMETHODS. Prospective observation and retrospective analysis of case histories were carried out, which included a total of 75 patients with primary chronic glomerulonephritis. RESULTS. The average age of the patients was 36.7 ± 12.3 years, of which 52 were males, 23 were women. The average length of service in a nephrological disease was 3.0 [1.0; 5.0] years. The calculated GFR values are 87.3 ± 31.2 ml / min / 1.73 m2. In the general population, the moderate degree of MCP-1 expression, estimated at 2 points, was 35 %, pronounced expression was found in 25 % of the respondents. In the mesangium of the glomeruli and in macrophages, the expressed degree of MCP-1 expression was 20 % and 16 %, respectively, which characterizes MCP-1 as a marker produced by resident cells. When studying the relationship of MCP-1 in blood with clinical parameters, a correlation was found with the values of total protein (Rs= –0.43; p <0.05), with erythrocyturia (Rs= –0.28; p <0.05), as well as with an albumin level (Rs= –0.5; p <0.05), which indicates the role of MCP-1 in the development of nephritic forms of glomerulonephritis. Depending on the severity of MCP-1 expression in biopsy specimens, the incidence of focal tubulointerstitial fibrosis with MCP-1 expression estimated at 1 point was 13.3 %, 2 points – 14.3 %, 3 points – 44.0 %. The revealed significant correlation between the serum level of MCP-1 and the severity of tubulointerstitial fibrosis confirms the MCP-1-mediated mechanism of progression of CKD. CONCLUSION. The relationship of serum and tissue forms of MCP-1 with the progression of tubulointerstitial fibrosis in chronic glomerulonephritis has been demonstrated. MCP-1-induced mesangial cell plays a critical role in the development of renal tubular damage, and its increased expression is associated with progressive tubulointerstitial fibrosis and decreased renal function.

MO210SERUM LEVELS OF PLASMINOGEN ACTIVATOR UROKINASE RECEPTOR AND CARDIOTROPHIN-LIKE CYTOKINE FACTOR 1IN PATIENTS WITH NEPHROTIC SYNDROME

Abstract Background and Aims The pathogenesis of primary focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) remains unknown to date. Some circulating permeability factors are discussed. This work assessed molecule candidates for permeability in serum samples of patients with nephrotic syndrome (NS). Method Forty-one patients with chronic glomerulonephritis (CGN) were included in our study. Seventeen patients had FSGS, 7 patients had MCD, 5 patients had membranoproliferative glomerulonephritis (MPGN), 6 patients had IgA nephropathy, and 6 patients had membranous nephropathy (MN). The laboratory data were compared with the clinical and histological features of nephritis. Serum levels of uPAR and CLCF-1 were measured by ELISA. Results The serum levels of plasminogen activator urokinase receptor (uPAR) were higher in FSGS patients before treatment than in patients with other morphological forms (MCD, IgA nephropathy, MN and MPGN). The levels of uPAR in serum did not correlate with daily proteinuria, serum creatinine/eGFR, arterial hypertension, the number of sclerosed glomeruli or tubulointerstitial fibrosis. No correlations were found between the levels of cardiotrophin-like cytokine factor 1 (CLCF-1) in serum and creatinine levels/glomerular filtration rate, the percentage of sclerosed glomeruli or the severity of tubulointerstitial fibrosis. There were no significant differences between the histological variants of nephritis. However, we found correlations between CLCF-1 levels and proteinuria (Rs = 0. 397, p = 0.015) and triglycerides levels (Rs = 0. 475, p = 0.003). Conclusion The data indicate an increase in the serum uPAR levels of FSGS before treatment. CLCF-1 levels in serum do not depend on histological forms of CGN, kidney function or immunosuppressive treatment, but they correlate with proteinuria and serum lipids in patients with NS.

MO272CLINICOPATHOLOGICAL CORRELATION OF APRIL AND BAFF IN IG A NEPHROPATHY- A SINGLE CENTER LONGITUDINAL OBSERVATIONAL STUDY

Abstract Background and Aims Aberrantly glycosylated IgA1 molecules are important in the pathogenesis of IgA nephropathy. A proliferation-inducing ligand (APRIL) and B-cell activating factor (BAFF) are cytokines involved in immunoglobulin class switching and production of galactose deficient IgA1(Gd IgA1). We aimed to study the association of serum levels of APRIL and BAFF with the clinical severity and pathological grading of IgA nephropathy (IgAN) and to assess the strength of the association by studying the clinicopathological correlation. Method The research study was conducted as a single-center longitudinal observational study. The study subjects were recruited based on the pathological diagnosis of primary IgA nephropathy. The plasma levels of APRIL, BAFF and Gd IgA1 were estimated using enzyme-linked immunosorbent assay (ELISA). All the study subjects were followed up for one year to study the renal outcome. Results In our study group of thirty-eight patients, the median estimated glomerular filtration rate(eGFR) was 33.9(15.9,79.4) ml/minute/1.73m2. The median levels of the cytokines APRIL and BAFF were 170.81(82.45, 550.61) ng/L and 6.66(3.39,16.33) ng/ml respectively. The baseline characteristics of the study group is given in table 1. APRIL levels had significant positive correlation with Gd IgA1 levels (correlation coefficient 0.556, p=0.003) in patients with IgAN. We also observed that patients with elevated APRIL levels had elevated BAFF levels also (correlation coefficient 0.657, p <0.001). Patients who had crescents, mesangial hypercellularity and endocapillary proliferation in biopsy had elevated APRIL and BAFF levels whereas patients with segmental sclerosis and tubular atrophy had low levels of APRIL(Table 2). However, the levels of APRIL and BAFF did not show any significant correlation with eGFR and proteinuria at time of presentation. At the end of one year, 12(31.5%) patients reached end stage renal disease (ESRD) and these patients had lower levels of APRIL, BAFF, and Gd IgA1. It was also seen that eighty-three percent of those who reached ESRD had chronic changes in biopsy like tubular atrophy and interstitial fibrosis(p=0.05). Hence the severity of tubulointerstitial fibrosis in histology correlated well with progression to end stage renal disease as seen in most glomerular diseases. But we did not find any association between APRIL, BAFF, and Gd IgA1 levels and the decline in eGFR over one year. Conclusion We conclude that levels of APRIL and BAFF are associated with elevated levels of Gd IgA1 in patients with IgAN and had a significant association with proliferative lesions in renal biopsy. But these cytokines levels did not have any association with the eGFR at time of presentation nor decline in eGFR over one year.

POS-452 SERUM LEVELS OF PLASMINOGEN ACTIVATOR UROKINASE RECEPTOR AND CARDIOTROPHIN-LIKE CYTOKINE FACTOR 1 IN PATIENTS WITH NEPHROTIC SYNDROME

The pathogenesis of primary focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) remains unknown to date. Some circulating permeability factors are discussed. This work assessed molecule candidates for permeability in serum samples of patients with nephrotic syndrome (NS). Forty-one patients with chronic glomerulonephritis (CGN) were included in our study. Seventeen patients had FSGS, 7 patients had MCD, 5 patients had membranoproliferative glomerulonephritis (MPGN), 6 patients had IgA nephropathy, and 6 patients had membranous nephropathy (MN). The laboratory data were compared with the clinical and histological features of nephritis. Serum levels of uPAR and CLCF-1 were measured by ELISA. Levels of uPAR in the serum of patients with CGN The levels of uPAR in serum did not correlate with daily proteinuria (Rs=-0.114, p=0.51), serum creatinine/eGFR (Rs=0.032, p=0.847 and Rs=-0.054, p=0.747, respectively), arterial hypertension (Rs=0.015, p=0.926), glomerulosclerosis percentage (Rs=0.364, p=0.07) or tubulointerstitial fibrosis (Rs=-0.189, p=0.517). There was no correlation with serum C-reactive protein levels (Rs = 0.226, p=0.173) Regarding the morphological forms of glomerulonephritis, the levels of uPAR were not significantly higher in FSGS patients than in MCD, IgA nephropathy, membranous nephropathy or membranoproliferative glomerulonephritis patients (Figure 1). However, the uPAR levels were significantly higher in FSGS patients before immunosuppressive treatment. In FSGS patients who already received immunosuppressive treatment, the uPAR levels were lower and comparable to those of the other groups (Figure 2). CLCF-1 in the serum of patients with CGN No correlations were found between the levels of CLCF-1 in serum and creatinine levels/glomerular filtration rate (Rs=0.285, p=0.079/Rs=-0.268, p=0.099), arterial hypertension (Rs=0.212, p=0.195), percentage of sclerosed glomeruli (Rs=0.28, p=0.127) or severity of tubulointerstitial fibrosis (Rs=0.238, p=0.413). There were no significant differences between the histological variants of nephritis (Figure 1). The levels of CLCF-1 did not depend on the therapy (Figure 2).However, we found correlations between CLCF-1 levels and proteinuria (Rs = 0. 397; p = 0.015) and lipid levels (Rs = 0. 475; p = 0.003). Additionally, correlations between CLCF-1 levels and triglyceride levels (Figure 3), very low-density lipoprotein (Rs = 0.467, p=0.045), and high-density lipoprotein levels (Rs = - 0.599, p=0.031) were found. View Large Image Figure ViewerDownload Hi-res image Download (PPT) Our data indicate a significant increase in the serum suPAR levels in untreated FSGS; immunosuppressive treatment can decrease the suPAR levels. CLCF-1 levels in serum did not depend on histological forms of nephritis or treatment, but it correlated with proteinuria and lipid levels in patients with nephrotic syndrome.

P0305DIAGNOSTIC VALUE OF TGF-B-1 AND ANG II EXCRERION IN URINE IN CHILDREN WITH VESICOURETERAL REFLUX DEPENDING ON THE THERAPEUTIC APPROACH

Abstract Background and Aims to determine the diagnostic value of profibrogenic cytokines of transforming growth factor (TGF-β1) and angiotensin II (AngII) in urine to detect the severity of tubulointerstitial fibrosis in children with vesicoureteral reflux (VUR) depending on the therapeutic approach. Method 117 patients aged 3 to 16 years (mean age 10.2 ± 4.5, 70.1% of girls) with VUR were examined. The control group consisted of 20 healthy children. All children underwent a complete nephrological examination. The levels of TGF-β1 and AngII were determined in morning urine using the ELISA method and counted for urine creatinine. To identify the severity of the lesion of the renal parenchyma, a static DMSA scintigraphy was performed. Results depending on the therapeutic approach, the children were divided into 2 groups: 1 gr. - children on conservative treatment (63.2%), 2 gr. - children, after surgical correction of VUR (36.8%). In each group, 3 subgroups were identified depending on the development of tubulo-interstitial fibrosis according to DMSA: A subgr. - without signs of sclerosis (15.4%), B subgr. - 1-2 foci (44.74%) and C subgr - > 3-4 foci of sclerosis (40.1%). All patients with VUR had a high urinary excretion of TGF-β1/Cr and AngII/Cr when compared with the control group (p<0.05). Regardless of the therapeutic approach, in subgroups A (without foci of sclerosis) and B (1-2 foci of sclerosis), patients had a statistically significantly lower level of excretion of these cytokines when compared with patients from subgroup C (p <0.05). No significant difference was found in the urinary excretion of TGF-β1/Cr and AngII/Cr depending on the therapeutic approach. Conclusion we established a reliable dependence of the excretion of TGF-β1/Cr and AngII /Cr in the urine on the severity of tubulo-interstitial fibrosis according to DMSA scintigraphy in children with VUR. At the same time, we did not note the dependence of the excretion of TGF-β1/Cr and AngII/Cr in the urine on the method of the therapeutic approach. Therefore, the study of the excretion of TGF-β1/Cr and AngII/Cr in the urine as non-invasive markers can be used as a criterion for the progression of nephropathy in VUR, regardless of treatment methods.

DCR2, a Cellular Senescent Molecule, Is a Novel Marker for Assessing Tubulointerstitial Fibrosis in Patients with Immunoglobulin A Nephropathy

Background/Aims: Stress-induced cell senescence, which contributes to cell cycle arrest and is independent of age, plays an important role in chronic kidney disease (CKD) progression. DcR2, as a senescent marker, exclusively expressed in senescent tubular epithelia. The objective of this study was to examine whether urinary DcR2 (uDcR2) could be a potential biomarker for tubulointerstitial fibrosis (TIF) in patients with immunoglobulin A nephropathy (IgAN). Methods: This study included 210 IgAN patients and 80 healthy volunteers, with uDcR2 levels measured using enzyme-linked immunosorbent assay. We examined the relationship among uDcR2/Cr levels, renal function, and pathological parameters, using regression analysis to identify risk factors for TIF and the area under the curve (AUC) approach to predict TIF. Renal DcR2 expression was quantified by immunohistochemistry. Co-expression of DcR2 with fibrotic markers (α-smooth muscle actin [α-SMA], collagen III) was analyzed by confocal microscopy. Results: Levels of uDcR2/Cr were significantly higher in IgAN patients and in those with more severe TIF, compared with healthy controls. Serum DcR2 levels were similar across groups. The proportion of IgAN patients with stages 1–2 CKD and T0 was highest among those with uDcR2/Cr <130 ng/g. In contrast, the majority of those with uDcR2/Cr >201 ng/g had stages 4–5 CKD and T2. Levels of uDcR2/Cr were positively associated with urinary albumin to creatinine ratio (ACR), urinary N-acetyl-β-D-glucosaminidase (uNAG)/Cr, and TIF scores and negatively associated with estimated glomerular filtration rate (eGFR). uDcR2/Cr, uNAG, ACR, and eGFR were independent predictors for TIF, with AUC of 0.907 for uDcR2/Cr. This AUC value was higher than that observed for eGFR, uNAG/Cr, or ACR. The sensitivity and specificity of uDcR2/Cr in predicting TIF were 87.0 and 80.5%, respectively. Moreover, uDcR2/Cr levels were positively associated with the percentage of renal DcR2 expression. Renal DcR2 co-localized with α-SMA and collagen III in the kidneys of IgAN patients. Conclusions: Levels of uDcR2/Cr were closely associated with the severity of TIF and renal function parameters. uDcR2/Cr represents a potential biomarker for predicting TIF in IgAN patients.

The associations of Bmi-1 with progression of glomerular chronic kidney disease .

Our previous studies indicated that Bmi-1 plays an important role in hypoxia-induced tubular epithelial-mesenchymal transition and the development of kidney fibrosis in cellular and animal models. However, circulating Bmi-1 levels in human chronic kidney disease (CKD) and their relation to progression remains unknown. We conducted a post-hoc analysis of a prospective cohort study. The blood samples and clinical data of 230 patients with glomerular CKD and 67 healthy adults were prospectively collected between January 2010 and June 2012. Serum Bmi-1 was measured using enzyme-linked immunosorbent assay (ELISA). CKD patients had significantly higher serum Bmi-1 concentrations than the healthy controls (496.4 (363.1-675.4) pg/mL compared with 257.3 (235.4-303.8) pg/mL, p<0.001). Serum Bmi-1 level inversely correlated with the estimated glomerular filtration rate (eGFR) (r = -0.346, p<0.001). In addition, positive correlations were identified between serum Bmi-1 levels and serum creatinine, blood urea nitrogen, cystatin C concentration, and the severity of tubulointerstitial fibrosis (r=0.248, p<0.001; r=0.245, p<0.001; r=0.273, p<0.001; r=0.536, p<0.001, respectively). Kaplan-Meier survival curves showed that a higher serum Bmi-1 level was associated with a shorter duration of renal survival. Cox multivariate analyses further demonstrated that serum Bmi-1 concentration was an independent prognostic factor for CKD patients (HR=6.48, p<0.001). Our study showed that high circulating Bmi-1 levels were associated with adverse kidney disease outcome, suggesting that Bmi-1 is a novel biomarker for glomerular CKD progression. More data from larger longitudinal studies are required to validate our findings. .

ANALYSIS OF PATOMORPHOLOGICAL MARKERS OF TUBULOINTERSTITIAL FIBROSIS IN PROTEINURIC PATIENTS WITH DIABETIC NEPHROPATHY

Background : The progression of diabetic nephropathy (DN) often accompanies by a combination with non-diabetic glomerulopathies (NDGP), which can significantly affect the prognosis and treatment of patients. However, the information about such influences, in particular, on the severity of tubulointerstitial fibrosis, one of the main pathomorphological prognostic criteria, on the renal parenchyma is not enough. AIM: To investigate the significance of NDGP for fibrotic processes kidney parenchyma in patients with diabetic nephropathy (DN). Patients (materials) and methods : Single-center retrospective analysis based on medical records of 51 patients (32 men, mean age: 49±13 years) with DN who underwent renal biopsy between 2002 and 2016. All patients were diagnosed as cases of DN -gr.№1, those were divided on “pure” DN-gr.№2 and DN-gr.№3 with NDGP. Results: Out of the 51 DN gr. №1 patients, 30 (60. %) had gr. № 2, 21 (40. %) had gr. №3. IgA nephropathy (IgAN)-20 % was the most common GN followed by focal segmental glomerulosclerosis (FSGS)-35%, and HCV –associated GN was the most common secondary GN. Patients with “pure” DN had lower estimated glomerular filtration rates (eGFR) and higher value of systolic blood pressure (SBP), glomerulosclerosis ( GS), peritubular capillarirtis ( PTC) and myofibroblasts quantity ( SMApositive cells). No significant between-group differences were observed with respect to majority of laboratory and morphological features. The activity of myofibroblasts positively correlated with tubular atrophy, focal sclerosis, the stage of diabetes and GS in gr. №2 in comparison with gr. № 3. Conclusions: The fibrosis of tubulointerstitium in the kidney of patients with DN accoppanied the pathomorphological markers such as SMA and PTC . There wasn’t significant evidences about the differences of fibrotic processes in the renal parenchyma in patients with and without NDHD.

Urinary vimentin mRNA as a potential novel biomarker of renal fibrosis.

Renal fibrosis is a histological outcome of chronic kidney disease (CKD) progression. However, the noninvasive detection of renal fibrosis remains a challenge. Here we constructed a renal fibrosis target mRNA array and used it to detect urinary mRNAs of CKD patients for investigating potential noninvasive biomarkers of renal fibrosis. We collected urine samples from 39 biopsy-proven CKD patients and 11 healthy controls in the training set. Urinary mRNA profiles of 86 genes showed a total of 21 mRNAs that were differentially expressed between CKD patients and controls (P < 0.05), and vimentin (VIM) mRNA demonstrated the highest change fold of 9.99 in CKD vs. controls with robust correlations with decline of renal function and severity of tubulointerstitial fibrosis. Additionally, VIM mRNA further differentiated patients with moderate-to-severe fibrosis from none-to-mild fibrosis group with an area of the curve of 0.796 (P = 0.008). A verification of VIM mRNA in the urine of an additional 96 patients and 20 controls showed that VIM is not only well correlated with renal function parameters but also correlated with proteinuria and renal fibrosis scores. Multiple logistic regression and receiver-operating characteristics analysis further showed that urine VIM mRNA is the best predictive parameter of renal fibrosis compared with estimated glomerular filtration rate, serum creatinine, and blood urea nitrogen. In addition, there is no improved predictive performance for the composite biomarkers to predict renal fibrosis severity compared with a single gene of VIM. Overall, urinary VIM mRNA might serve as a novel independent noninvasive biomarker to monitor the progression of kidney fibrosis.

Epigallocatechin-3-gallate attenuates unilateral ureteral obstruction-induced renal interstitial fibrosis in mice.

The severity of tubulointerstitial fibrosis is regarded as an important determinant of renal prognosis. Therapeutic strategies targeting tubulointerstitial fibrosis have been considered to have potential in the treatment of chronic kidney disease. This study aims to evaluate the protective effects of (-)-epigallocatechin-3-gallate (EGCG), a green tea polyphenol, against renal interstitial fibrosis in mice. EGCG was administrated intraperitoneally for 14 days in a mouse model of unilateral ureteral obstruction (UUO). The results of our histological examination showed that EGCG alleviated glomerular and tubular injury and attenuated renal interstitial fibrosis in UUO mice. Furthermore, the inflammatory responses induced by UUO were inhibited, as represented by decreased macrophage infiltration and inflammatory cytokine production. Additionally, the expression of type I and III collagen in the kidney were reduced by EGCG, which indicated an inhibition of extracellular matrix accumulation. EGCG also caused an up-regulation in α-smooth muscle actin expression and a down-regulation in E-cadherin expression, indicating the inhibition of epithelial-to-mesenchymal transition. These changes were found to be in parallel with the decreased level of TGF-β1 and phosphorylated Smad. In conclusion, the present study demonstrates that EGCG could attenuate renal interstitial fibrosis in UUO mice, and this renoprotective effect might be associated with its effects of inflammatory responses alleviation and TGF-β/Smad signaling pathway inhibition.

CD2AP mRNA in urinary exosome as biomarker of kidney disease

AimsPodocyte injury plays an important role in the pathogenesis of kidney disease. Urinary exosomes are microvesicles released by tubular epithelial cells and podocytes containing information of their originated cells. This study investigated for the first time whether podocyte related mRNA in urinary exosome could serve as novel biomarkers for kidney disease. MethodsUrine samples were collected from 32 patients of kidney disease who underwent kidney biopsy and 7 controls. CD2AP, NPHS2 and synaptopodin were detected by real-time RT-PCR on RNA isolated from urinary exosome. ResultsThe pellet microvesicles were positively stained with exosome and podocyte marker, AQP2, CD9 and nephrin. CD2AP mRNA was lower (p=0.008) in kidney disease patients compared with controls and decreased with the increasing severity of proteinuria (p=0.06). CD2AP correlated with serum creatinine (r=−0.373, p=0.035), BUN (r=−0.445, p=0.009) and eGFR (r=0.351, p=0.046). Neither NPHS2 nor synaptopodin correlated with parameters of renal function. CD2AP mRNA correlated negatively with 24hour urine protein (r=−0.403, p=0.022), severity of tubulointerstitial fibrosis (r=−0.394, p=0.026) and glomerulosclerosis (r=−0.389, p=0.031) and could discriminate kidney disease from controls with AUC of 0.821 (p=0.008). ConclusionsUrinary exosome mRNA of CD2AP might be a non-invasive tool for detecting both renal function and fibrosis of kidney disease.

Factors promoting development of renal tubulointerstitial lesions in patients with diabetes mellitus

Aim. To identify profibrogenic mediators, markers of endothelial dysfunction and hemostasis in patients with diabetes mellitus (DM) and chronickidney disease (CKD). Materials and methods. The study included 120 patients with DM and 20 age-matched normotensive subjects without DM showing the glomerularfiltration rate (GFR) &gt; 60 ml/min/1.73 m3. Four groups of patients were distinguished: 1 - DM2 patients without renal pathology (n=33), 2 - DM2 patients with diabetic nephropathy (n=24), 3 - DM2 patients with ischemic nephropathy (IN) (n=33) verified by contrast visualization techniques(multispiral CM of abdominal aorta and renal arteries, abdominal angiography of renal arteries or MR angiography of renal arteries and abdominal aorta), 4 - DM1 patients with DN (n=30). Clinical examination included assessment of complaints, analysis of medical history of the main diseaseand concomitant disorders, determination of the main clinical and biochemical characteristics of blood and urine, measurement of НbА1с and 24-hralbuminuria (AU) by standard methods, estimation of GFR by the MDRD formula, ECG, echocardiography, 24-hr AP monitoring, counseling bycardiologist and ophthalmologist (fundal examination by ophthalmoscopy). Standard kits were used to detect profibrogenic mediators and markersof endothelial dysfunction including transforming growth factor-beta (TGF-b), angiotensin II (AT II), monocyte chemoattractant protein (MCP-1),regulated on activation normal T cell expressed and secreted (RANTES), adhesion factors (intracellular adhesion molecule (ICAM-1), vascular celladhesion molecule (VCAM-1) vascular endothelial growth factor (VEGF), interleukin-6 (IL-6), asymmetric dimethylargnine (ADMA), homocysteine(HCYST), metalloproteinases (MMP), von Willebrand factor (vWF), plasminogen activator inhibitor (PAI-I). Results. DM patients with CKD had elevated blood profibrogenic cytokine (MCP-1, TGF-1b, IL-6) and extracellular matrix degradation factor(MMP-9) levels compared with patients without CKD and healthy subjects. These changes were unrelated to the type of diabetes or the cause ofnephropathy, which suggests their contribution to renal pathology through the universal mechanism of tubulointerstitial fibrosis. Activation of profibrogeniccytokines in DM patients with CKD was closely associated with endothelial dysfunction manifest as enhanced production of blood adhesive angiogenic, thrombogenic factors (FW, PAI, VICAM, sICAM, VEGF), and endothelium-affecting factors (ADMA, homocysteine). Mediators of inflammationand fibrogenesis in these patients negatively correlated with GFR and positively with AU, the main markers of renal dysfunction. Hyperuricemia,TGF-1b, ADMA, and MCP-1 are considered to be the risk factors of impaired renal filtration function. Conclusion. The level of profibrogenic cytokines and ndothelial dysfunction factors in DM patients with different renal lesions reflects severity of tubulointerstitialfibrosis. It may be used for the purpose of prognostication and substantiation of intensification of secondary prophylaxis of renal insufficiency.

Expression of Notch pathway proteins correlates with albuminuria, glomerulosclerosis, and renal function

Recent studies indicate that the Notch signaling pathway plays an important role in the development of diabetic kidney disease and focal segmental glomerulosclerosis (FSGS). Here we analyzed the degree of expression and localization of Notch ligands (Jagged1 and Delta1) and activated (cleaved) receptors (Notch1 and Notch2) in healthy human kidneys and in renal biopsies from a wide variety of kidney diseases. These included patients with minimal change disease, membranous nephropathy, lupus nephritis ISN/RPS classes III/IV/V, hypertensive nephrosclerosis, crescentic glomerulonephritis, tubulointerstitial fibrosis, IgA nephropathy, diabetic kidney disease, and FSGS. We found that cleaved Notch1, Notch2, and Jagged1 are expressed on podocytes in proteinuric nephropathies and their level of expression correlated with the amount of proteinuria across all disease groups. The degree of glomerulosclerosis correlated with podocyte expression of cleaved Notch1, while the severity of tubulointerstitial fibrosis and the estimated glomerular filtration rate correlated with expression of cleaved Notch1 in the tubulointerstitium. Hence, our results raise the possibility that Notch pathway activation is a common mechanism in the pathophysiology of a wide range of acquired renal diseases.

Predictors of outcome in idiopathic rapidly progressive glomerulonephritis (IRPGN)

BackgroundSmall vessel vasculitides are known to follow a devastating course towards end-stage renal disease, unless treated with immunosuppressive regiments. We investigated the value of clinical, histological and immunohistochemical parameters as predictors of outcome at diagnosis in patients with pauci immune necrotizing glomerulonephritis.MethodsIn 34 patients the percentage and evolution stage of crescents, the presence of glomerular necrosis, the degree or severity of arteriosclerosis, as well as the extent of tubulointerstitial infiltration, interstial fibrosis and tubular atrophy were assessed. Monoclonal antibodies were used to identify infiltrating macrophages, α-SMA(+) and PCNA(+) cells, the expression of integrins α3β1 and LFA-1β, the adhesion molecule ICAM-1, the growth factor TGF-β1 and the terminal complement component C5b-9.Results24 pts (70.6%) showed a complete or partial response to the treatment. The follow-up period was 20 ± 22 months. At multivariate analysis, serum CRP (p = 0.024), the intensity of tubular expression of C5b-9 (p < 0.0001) as well as the extent of glomerular and tubular expression of α3β1 integrin (p = 0.001 and 0.008 respectively) independently predicted the response to treatment. The response rate was better in ANCA(+) pts (p = 0.008). The extent of interstitial infiltrate (p < 0.0001), the severity of tubulointerstitial fibrosis (p < 0.0001) and the severity of tubular TGF-β1 expression (p < 0.0001) were independent predictors of long term outcome of renal function.ConclusionPatients with ANCA-associated renal vasculitis seem to respond better to the treatment. Acute phase reactants, such as CRP, implying a more intense parenchymal inflammatory reaction, as well as the intensity of the de novo expression of C5b-9 and the glomerular and tubular expression of α3β1 integrin predict the response to therapy. The severity of TIN lesions and of the tubulo-interstitial TGF-β1 and C5b-9 expression predict an unfavourable outcome.

Factors influencing the course and the response to treatment in primary focal segmental glomerulosclerosis.

The clinical course of primary focal segmental glomerulosclerosis (FSGS) varies and there is considerable controversy as to which factors are of importance in determining prognosis or response to therapy. The aim of this study was to identify clinical, pathological or immunohistochemical features at biopsy that could identify patients with progressive disease who might benefit from treatment, and predict long-term outcome. The clinical and pathological findings of 33 adult patients with primary FSGS were retrospectively analysed in order to identify features at biopsy that could be predictive of outcome or response to treatment. For this purpose an immunohistochemical study was also performed, using monoclonal antibodies against intracellular adhesion molecules-1, C5b-9, alpha 3 beta 1 integrin, alpha-smooth-muscle actin (SMA), and TGF-beta1. At biopsy 17 patients (51%) were nephrotic and 16 (49%) non-nephrotic. Of the nephrotic patients, 11 were treated and six received only symptomatic therapy. Initial treatment with prednisolone (Pred) for 6-12 months (average 9 months) resulted in remission in 64% of nephrotic patients. To those with partial or no response, cyclosporin (CsA) or cyclophosphamide was given. At the end of follow-up (mean 57 months) three nephrotic patients (28%) were in complete remission, six (54%) in partial remission, and two (18%) did not respond to the treatment. In the seven treated non-nephrotic patients, Pred induced a complete remission in two (28%), a partial remission in three (44%), while two patients (28%) did not respond. Plasma creatinine remained stable in nephrotic patients who responded and it almost doubled in non-responders. Plasma creatinine also remained unchanged in treated non-nephrotic patients who responded to Pred, while two non-responders reached end-stage renal disease (ESRD). In contrast, 50% of untreated nephrotic patients and 67% of untreated non-nephrotic patients progressed to ESRD. Multivariate analysis showed only age and plasma creatinine at biopsy to have an independent predictive value for renal survival in nephrotic patients. This analysis also demonstrated that only the severity of interstitial fibrosis predicted the response to the treatment. In addition, the tubulointerstitial but not the glomerular expression of C5b-9, alpha 3 beta 1 integrin, alpha-SMA, and TGF-beta1 was significantly more extensive in non-responders and correlated with renal function at biopsy. However, only tubulointerstitial expression of TGF-beta1 independently correlated with the degree of renal function impairment at biopsy, but none of the above markers independently predicted renal survival or response to therapy. Nephrotic patients with FSGS may benefit from a more prolonged course of Pred. Nephrotic patients responding to treatment have a significantly better renal survival than non-responders. Age and plasma creatinine at biopsy are independent risk factors leading to ESRD. The severity of tubulointerstitial fibrosis is predictive of response to therapy.

The effect of oral protease administration in the rat remnant kidney model.

It has been demonstrated that intraperitoneal administration of proteolytic enzymes ameliorates the progression of renal diseases in various animal models. In the present study, we employed the rat remnant kidney model to study the effectiveness of oral administration of proteases. Twenty male Wistar rats underwent sham operation (CTRL), while 25 were subjected to 5/6 nephrectomy (5/6 NX). Rats were randomised into placebo (PL) (2 ml tap water/day by gavage), or Phlogenzym (E; fixed mixture of trypsin 2.42 mg, bromelain 4.54 mg, and rutozid 5.04 mg added as antioxidant, in 2 ml tap water daily by gavage) treated group. Duration of the study was 45 days. Rats were pair-fed. Enzyme treatment exerted salutary effects on various functional and morphological parameters. Proteinuria was higher in both 5/6 NX group rats throughout the study. Administration of proteases ameliorated its rise effectively (data at sacrifice: CTRL-PL 6.27 +/- 1.25, CTRL-E 9.27 +/- 0.99, 5/6 NX-PL 74.04 +/- 21.33, 5/6 NX-E 39.09 +/- 7.93 mg/24 h; P < 0.01). Increased urinary excretion of the fibrogenic cytokine transforming growth factor (TGF-beta 1) was improved, too (CTRL-PL 0.349 +/- 0.051, CTRL-E 0.693 +/- 0.230, 5/6 NX-PL 3.044 +/- 0.540, 5/6 NX-E 1.390 +/- 0.238 ng/mumol creatinine; P < 0.05). At sacrifice, tubulointerstitial fibrosis was less pronounced in E-treated rats. Correspondingly, the volume fraction of tubulointerstitial tissue in the renal cortex was improved in 5/6 NX-E rats (CTRL-PL 9.9 +/- 0.2, CTRL-E 10.0 +/- 0.2, 5/6 NX-PL 17.9 +/- 1.8, 5/6 NX-E 13.8 +/- 0.9%; P < 0.05). The protein/DNA ratio in isolated glomeruli and tubules, as an estimate of glomerular matrix accumulation and hypertrophy of tubules, was enhanced in 5/6 NX groups and a tendency towards lower values was observed after E treatment. Renal function as evaluated by serum creatinine and urea levels was not influenced by the enzyme therapy. No between-group differences in blood pressure were observed. In summary, oral administration of proteolytic enzymes improved proteinuria and urinary TGF-beta 1 excretion, as well as the severity of tubulointerstitial fibrosis without signs of toxicity.

Tubular epithelial-myofibroblast transdifferentiation in progressive tubulointerstitial fibrosis in 5/6 nephrectomized rats

Tubulointerstitial fibrosis is the final common pathway to end-stage renal failure. The present study investigated the potential role of tubular epithelial cells (TEC) in progressive fibrosis in the rat remnant kidney model. Rats underwent 5/6 nephrectomy or a sham operation (control), and groups of six animals were killed at weeks 1, 3, 5, 9, 13, 17 and 21. Immunohistochemistry staining and in situ hybridization at week 3 after nephrectomy demonstrated de novo expression of alpha-smooth muscle actin (alpha-SMA)--a marker of smooth muscle cells and myofibroblasts--by TEC that was invariably associated with disruption of the tubular basement membrane (TBM). This phenotypic evidence of tubular epithelial-myofibroblast transdifferentiation was supported by ultrastructural studies identifying the presence of characteristic actin microfilaments and dense bodies within TEC with a transformed morphology. In the late stage of this apparent tubular epithelial-myofibroblast transdifferentiation, TEC lost apical-basal polarity and tight junctions, became elongated, detached from the TBM, separated from neighboring cells and appeared to migrate into the peritubular interstitium through the damaged basement membrane. Indeed, focal peritubular accumulation of alpha-SMA+ myofibroblasts and local tubulointerstitial fibrosis was closely associated with alpha-SMA+ tubules, suggesting a tubular epithelial origin for some of these cells. Quantitative analysis found a significant correlation between the number of alpha-SMA+ TEC and the accumulation of interstitial alpha-SMA+ myofibroblasts and the severity of tubulointerstitial fibrosis (both P < 0.001). This study provides phenotypic and morphological evidence to support the hypothesis that TEC are pro-fibrogenitor cells capable of tubular epithelial-myofibroblast transdifferentiation in progressive renal fibrosis. In addition, we postulate that disruption of the TBM, which facilitates epithelial cell contact with the interstitial matrix, promotes this process of transdifferentiation.