TGF-β has been implicated as a major pathogenic factor in diabetic nephropathy. This randomized, double-blind, phase 2 study assessed whether modulating TGF-β1 activity with a TGF-β1–specific, humanized, neutralizing monoclonal antibody (TGF-β1 mAb) is safe and more effective than placebo in slowing renal function loss in patients with diabetic nephropathy on chronic stable renin-angiotensin system inhibitor treatment. We randomized 416 patients aged ≥25 years with type 1 or type 2 diabetes, a serum creatinine (SCr) level of 1.3–3.3 mg/dl for women and 1.5–3.5 mg/dl for men (or eGFR of 20–60 ml/min per 1.73 m²), and a 24-hour urine protein-to-creatinine ratio ≥800 mg/g to TGF-β1 mAb (2-, 10-, or 50-mg monthly subcutaneous dosing for 12 months) or placebo. We assessed a change in SCr from baseline to 12 months as the primary efficacy variable. Although the Data Monitoring Committee did not identify safety issues, we terminated the trial 4 months early for futility on the basis of their recommendation. The placebo group had a mean±SD change in SCr from baseline to end of treatment of 0.33±0.67 mg/dl. Least squares mean percentage change in SCr from baseline to end of treatment did not differ between placebo (14%; 95% confidence interval [95% CI], 9.7% to 18.2%) and TGF-β1 mAb treatments (20% [95% CI, 15.3% to 24.3%], 19% [95% CI, 14.2% to 23.0%], and 19% [95% CI, 14.0% to 23.3%] for 2-, 10-, and 50-mg doses, respectively). Thus, TGF-β1 mAb added to renin-angiotensin system inhibitors did not slow progression of diabetic nephropathy.

The risk of diabetic nephropathy is partially genetically determined. Diabetic nephropathy is linked to a gene locus on chromosome 18q22.3-q23. We aimed to identify the causative gene on chromosome 18 and to study the mechanism by which the product of this gene could be involved in the development of diabetic nephropathy. DNA polymorphisms were determined in 135 case (diabetic nephropathy) and 107 control (diabetes without nephropathy) subjects. The effect of carnosine on the production of extracellular matrix components and transforming growth factor-β (TGF-β) after exposure to 5 and 25 mmol/l d-glucose was studied in cultured human podocytes and mesangial cells, respectively. A trinucleotide repeat in exon 2 of the CNDP1 gene, coding for a leucine repeat in the leader peptide of the carnosinase-1 precursor, was associated with nephropathy. The shortest allelic form (CNDP1 Mannheim) was more common in the absence of nephropathy (P = 0.0028, odds ratio 2.56 [95% CI 1.36–4.84]) and was associated with lower serum carnosinase levels. Carnosine inhibited the increased production of fibronectin and collagen type VI in podocytes and the increased production of TGF-β in mesangial cells induced by 25 mmol/l glucose. Diabetic patients with the CNDP1 Mannheim variant are less susceptible for nephropathy. Carnosine protects against the adverse effects of high glucose levels on renal cells.

Progressive CKD is generally detected at a late stage by a sustained decline in eGFR and/or the presence of significant albuminuria. With the aim of early and improved risk stratification of patients with CKD, we studied urinary peptides in a large cross-sectional multicenter cohort of 1990 individuals, including 522 with follow-up data, using proteome analysis. We validated that a previously established multipeptide urinary biomarker classifier performed significantly better in detecting and predicting progression of CKD than the current clinical standard, urinary albumin. The classifier was also more sensitive for identifying patients with rapidly progressing CKD. Compared with the combination of baseline eGFR and albuminuria (area under the curve [AUC]=0.758), the addition of the multipeptide biomarker classifier significantly improved CKD risk prediction (AUC=0.831) as assessed by the net reclassification index (0.303±−0.065; P<0.001) and integrated discrimination improvement (0.058±0.014; P<0.001). Correlation of individual urinary peptides with CKD stage and progression showed that the peptides that associated with CKD, irrespective of CKD stage or CKD progression, were either fragments of the major circulating proteins, suggesting failure of the glomerular filtration barrier sieving properties, or different collagen fragments, suggesting accumulation of intrarenal extracellular matrix. Furthermore, protein fragments associated with progression of CKD originated mostly from proteins related to inflammation and tissue repair. Results of this study suggest that urinary proteome analysis might significantly improve the current state of the art of CKD detection and outcome prediction and that identification of the urinary peptides allows insight into various ongoing pathophysiologic processes in CKD.

Background. This report describes data collected by the Czech Registry of Renal Biopsies (CRRB). Methods. Twenty-eight centres provided data on all biopsies of native kidneys performed in the Czech Republic (population 10.3 million) over the period 1994–2000. Data on serum creatinine concentration (sCr), 24 h proteinuria, haematuria, serum albumin level, arterial hypertension, diabetes mellitus, histological diagnosis and complications after renal biopsy were collected. Results. Altogether 4004 biopsies in 3874 patients were performed (males 57.9%, children ≤15 years 17.7%, elderly >60 years 14.3%). Microhaematuria was present in 65.9%, macrohaematuria in 9.2%, nephrotic proteinuria (≥3.5 g/24 h) in 39.3%, and low-grade proteinuria (400 µmol/l. The most frequent renal diseases were primary (59.8%) and secondary (25.4%) glomerulonephritis (GN). Tubulointerstitial nephritis (TIN) was observed in 4.4% and hypertensive nephroangiosclerosis in 3.4%. The samples were non-diagnostic in 4.6%. Among primary GNs, the most frequent diagnoses were: IgA nephropathy (IgAN) 34.5%, minimal change disease (MCD) 12.4%, non-IgA mesangioproliferative GN (MesGN) 11.3%, focal segmental glomerulosclerosis (FSGS) 10.8% and membranous GN (MGN) 9.3%. Among secondary GNs, systemic lupus erythematosus (SLE) represented 23.0%, necrotizing vasculitis (NV) 15.5%, Henoch–Schönlein purpura 5.7%, thin basement membrane glomerulopathy (TBN) 19.3%, Alport syndrome 6.9%, renal amyloidosis 9.9% and myeloma kidney 2.9%. Among children, the most common were IgAN (19.2%), MCD (17.6%) and TBM glomerulopathy (12.3%), while among the elderly the most common were MGN (11.0%), NV (10.7%) and amyloidosis (9.6%). The most common in patients with nephrotic proteinuria were MCD (50.5%) among children, but IgAN (24.6%) in adults aged 16–60 years and MGN (16.8%) among the elderly. IgAN (21.3%) and FSGS (8.3%) were the most common diagnoses among patients with mild renal insufficiency, but TIN (11.6%) and NV (11.3%) were the most common in more advanced renal insufficiency. Since 1999, diabetic patients represented 12.2% of adults, with mean proteinuria 8.9 g/24 h; diabetic glomerulosclerosis was found in 42.4% (with microhaematuria present in 66%) and non-diabetic renal diseases in 47.5% (IgAN in 17.5%, MGN and NAS in 11.1% and NV in 9.5%). The mean annual incidence (per million population) was: primary GN 32.4, secondary GN 13.8, IgAN 11.2, MCD 4.0, MesGN 3.7, FSGS 3.5, SLE 3.2, MGN 3.0, TBM 2.7, TIN 2.4 and NV 2.1. Ultrasound needle guidance was used in 56%, preferably in children (79%). The frequency of serious complications (gross haematuria, symptomatic haematoma, blood transfusion) remained at 3%. Conclusion. The CRRB provides important data on the epidemiology of GN based on a whole country population.

Despite the potential for patient-reported outcome measures (PROMs) and experience measures (PREMs) to enhance understanding of patient experiences and outcomes they have not, to date, been widely incorporated into renal registry datasets. This report summarizes the main points learned from an ERA-EDTA QUEST-funded consensus meeting on how to routinely collect PROMs and PREMs in renal registries in Europe. In preparation for the meeting, we surveyed all European renal registries to establish current or planned efforts to collect PROMs/PREMs. A systematic review of the literature was performed. Publications reporting barriers and/or facilitators to PROMs/PREMs collection by registries were identified and a narrative synthesis undertaken. A group of renal registry representatives, PROMs/PREMs experts and patient representatives then met to (i) share any experience renal registries in Europe have in this area; (ii) establish how patient-reported data might be collected by understanding how registries currently collect routine data and how patient-reported data is collected in other settings; (iii) harmonize the future collection of patient-reported data by renal registries in Europe by agreeing upon preferred instruments and (iv) to identify the barriers to routine collection of patient-reported data in renal registries in Europe. In total, 23 of the 45 European renal registries responded to the survey. Two reported experience in collecting PROMs and three stated that they were actively exploring ways to do so. The systematic review identified 157 potentially relevant articles of which 9 met the inclusion criteria and were analysed for barriers and facilitators to routine PROM/PREM collection. Thirteen themes were identified and mapped to a three-stage framework around establishing the need, setting up and maintaining the routine collection of PROMs/PREMs. At the consensus meeting some PROMs instruments were agreed for routine renal registry collection (the generic SF-12, the disease-specific KDQOL™-36 and EQ-5D-5L to be able to derive quality-adjusted life years), but further work was felt to be needed before recommending PREMs. Routinely collecting PROMs and PREMs in renal registries is important if we are to better understand what matters to patients but it is likely to be challenging; close international collaboration will be beneficial.