Publishable final activity Report Project 018733 PREDICTIONS Specific Targeted Research Project FP6-2004-LIFESCIHEALTH-5 The Identification of Risk Factors for the Development of Diabetic Nephropathy: The PREDICTIONS Project Publishable final activity report PREDICTIONS Period covered: from 01.12.05 to 28.02.09 Start date of project: 01.12.05 Date of preparation: 27.04.09 Duration: 39 Months Project coordinator name: Prof. Dr. Bart Janssen Project coordinator organisation name: Ruprecht Karls University Heidelberg Revision 1 Publishable executive summary 1. Project execution The PREDICTIONS (PREvention of Diabetic ComplicaTIONS) Consortium was established in 2004, the project started December 1st, 2005. The general objective of the PREDICITONS Project was to develop improved strategies for the prevention and management of diabetic nephropathy (DN). The main question was “Which biomarkers are associated with the risk to develop DN?”. To Contact: Project Co-ordinator: this end, the problem of DN as a major Prof. Dr. Bart Janssen diabetic vascular complication was approached Formerly: University of Heidelberg Now: Service XS in a translational research effort on the Plesmanlaan 1d genomic, proteomic and clinical level. 2333 BZ Leiden Specific scientific objectives from translational b.janssen@servicexs.com research were to identify pathophysiologically Web site: www.predictions-project.eu relevant genes and biomarkers correlated with onset, progression and response to therapy in DN. Several partners contributed to the work of PREDICTIONS. Coordinator of the study was Prof. Bart Janssen from the Ruprecht-Karls-University of Heidelberg (Partner 1). Other contractors are mentioned at the end of this report. A central webpage was used for dissemination and communication of contractors and interested public (http://www.predictions-project.eu). The Consortium was formed around Prof. Dr. med. Fokko J. van der Woude who had worked together with most of the contractors before the start of this project. His premature death on December 4th, 2006 has to be considered as a major drawback to the Consortium, because although his functions were taken over by other consortium members his motivating force, his creative mind and his solutions to problems were frequently missed. To develop the first comprehensive profile of diabetic nephropathy in type 2 diabetes, several methodologies were used. The core of the project was the case-control trial, recruiting retrospectively and prospectively 457 patients in total. Furthermore, samples from patients who had previously undergone therapy trials were used to evaluate biochemical markers. As not all examinations could be performed in all patients, the data packages are shown in the scheme. 2 Cover and matching criteria Medical history Concomitant medication Clinical exam 457 Laboratory Hannover Polypeptide factors 148 Heidelberg Carnosinase 207 Warwick Proteindamage 159 Graz Vitamins 162 Leiden/Heidelberg SNP Genotypes 469 Heidelberg 469 Microsatellite Genotypes Figure 1. Scheme of data packages There were seven specific scientific and technological objectives of the PREDICTIONS-Project which will be elaborated on in the text: 1. Independent confirmation of the identification of CNDP1 as a risk factor 2. Re-evaluation of previously proposed genetic variants 3. Expression profiling for the identification of genes associated with the pathogenesis of DN 4. Analysis of the urinary proteome for the identification of a secretion patterns associated both with a specific genetic trait and a high-risk vascular profile of diabetic patients 5. Assessment of biomarkers of protein glycation and oxidative stress as prognostic factors 6. Exploration of the association between biomarkers and response to treatment 7. Development of a risk model In 2005 we published data from a genetic study showing that a trinucleotide repeat in exon 2 of the CNDP1 gene, coding for a leucine repeat in the leader peptide of the carnosinase-1 precursor is associated with diabetic nephropathy. The shortest allelic form (CNDP1 Mannheim) was more common in the absence of nephropathy [1]. Concerning the independent confirmation of CNDP1 as a risk factor, in collaboration with the group of Barry Freedman (Wake Forest University School of Medicine Winston-Salem, NC, USA), 858 European Americans were examined. It could be shown that the frequency of the 5-5 leucine genotype is more frequent in healthy controls and in diabetic patients without nephropathy compared to definite DN cases and the combination of definite and presumable DN cases, therefore confirming our findings[2]. Moreover, we found a null-allele in the CNDP1 gene causing a frame-shift and a non-functional enzyme [3]. This allele has a frequency of almost 1% in the general population but has not been observed in DN so far. To examine the relevance of the CNDP1-genotype in different kidney diseases, 875 dialysis patients from the NECOSAD cohort (LUMC, Netherlands), 292 dialysis patients from the MIA cohort (Karolinska institute, Sweden), 158 patients with diabetes from the SMART cohort (UMC Utrecht, Netherlands) were genotyped. Their genotypes were compared to 732 healthy Caucasian 3 subjects from the NECOSAD cohort and 334 healthy Caucasian subjects from the MIA cohort. There was no association of the CNDP1 genotype with patients who became dialysis dependent due to end stage diabetic nephropathy (p=0.29) in the NECOSAD cohort. The latter lack of association of CNDP1 with end stage DN was confirmed in an independent patient cohort from the Karolinska Institute (p=0.15). The mortality risk of dialysis patients due to chronic glomerulonephritis was significantly dependent on their CNDP1 genotype (log rank, p < 0.01). The CNDP1 genotype was associated with microalbuminuria in patients with diabetes, when compared to diabetic patients without albuminuria. Not only CNDP1 genotype was examined, but also functional differences between different genotypes were further evaluated. As published previously [Janssen et al. 2005], the shortest allelic form (CNDP1 Mannheim) was associated with lower serum carnosinase levels. To confirm this finding, special constructs of the leucine repeat were tested in Cos cells. These invitro studies confirmed that alleles with 4 or 5 leucine repeats have a poorly functioning leader peptide, leading to a reduced secretion of the protein and reduced carnosinase activity [4]. As we did not expect CNDP1 to be the only DN-causing factor we suspected additional factors to play an important role in ‘CNDP1- independent’ DN and therefore re-evaluated previously proposed genetic variants. This was done in a case-control study: cases were defined as patients with diabetes type 2, a diabetes duration of at least 5 years, age between 35 and 75 years, presence of macroalbuminuria (albumin>300mg/day in the urine) and presence of diabetic retinopathy, controls were defined as patients with diabetes type 2, a diabetes duration of at least 5 years and normoalbuminuria. Cases and controls were matched for center, sex and diabetes duration. A total of 457 patients could be examined. In the application for the PREDICTIONS-Project, the SLC12A3 gene [5] was specially mentioned, which is, together with CNDP1 the only candidate gene resulting from systematic genome studies so far. The association with diabetic nephropathy was found in Japanese patients with type 2 diabetes. Recently, another group [6] could not confirm that a genetic variation at the SLC12A3 locus explains the risk for advanced diabetic nephropathy in Caucasian type 2 diabetics. We examined a total of 41 SNP and 5 microsatellite markers in 38 different genes (Table 1). The single nucleotide polymorphism (SNP) analysis was performed using the Biomark® platform (Figure 2). Using this 96x96 technology analysing 41 markers in 457 samples, a lot of time and money could be saved, otherwise more than 200 96-wells plates would have had to be used. The microsatellite markers were determined using fragment-analysis. After statistical analysis, due to lack of power after adjusting for multiple testing, no significant association could be found. On the nominal level however, toll-like receptor 4 (TLR4) was found to be significant (p=0.006). The Asp299Gly SNP of TLR4, is a functional variant that has not been reported to be genetically associated with DN before. TLR4 is an activator of the NF-κB inflammatory pathway. 4 Table 1. Genes examined in the course of PREDICTIONS and their corresponding gene symbol. Gene Name Gene Symbol angiotensin I converting enzyme (peptidyl-dipeptidase A) 1 adducin 1 (alpha) advanced glycosylation end product-specific receptor angiotensinogen (serpin peptidase inhibitor, clade A, member 8) angiotensin II receptor, type 1 Aldose reductase apolipoprotein E caldesmon 1 chymase 1, mast cell carnosine dipeptidase 1 (metallopeptidase M20 family) cytochrome P450, family 11, subfamily B, polypeptide 2 UniSTS:61895 engulfment and cell motility 1 ectonucleotide pyrophosphatase/phosphodiesterase 1 glyoxalase I guanine nucleotide binding protein (G protein), beta polypeptide 3 heparan sulfate proteoglycan 2 interleukin 1, beta interleukin 6 (interferon, beta 2) chemokine (C-C motif) ligand 2 Matrix metalloproteinase 9 5,10-methylenetetrahydrofolate reductase (NADPH) nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha nephrosis 2, idiopathic, steroid-resistant (podocin) natriuretic peptide precursor A Neuropeptide Y Plasminogen activator inhibitor 1 paraoxonase 1 paraoxonase 2 protein kinase C, beta Pvt1 oncogene (non-protein coding) solute carrier family 12 (sodium/chloride transporters), member 3 solute carrier family 2 (facilitated glucose transporter), member 1 transforming growth factor, beta 1 toll-like receptor 4 tumor necrosis factor (TNF superfamily, member 2) TSC22 domain family, member 1 unc-13 homolog B ACE ADD1 AGER AGT AGTR1 AKR1B1 APOE CALD1 CMA1 CNDP1 CYP11B2 D10S1435 ELMO1 ENPP1 GLO1 GNB3 HSPG2 IL1B IL6 MCP1 / CCL2 MMP9 MTHFR NFKBIA NPHS2 NPPA NPY PAI1 PON1 PON2 PRKCB PVT1 SLC12A3 SLC2A1/ GLUT1 TGFB1 TLR4 TNF TSC22D1 UNC13B Asp299Gly carriers are known to have lower levels of proinflammatory cytokines, acute-phase reactants, interleukin-6 and fibrinogen. Although these subjects were found to be more susceptible to severe bacterial infections, they have a lower risk of atherosclerosis, suggestive evidence that these individuals also have a lower risk for DN. 5 To perform expression profiling for the identification of genes associated with the pathogenesis of DN partner 3 has established a methodology to identify genes and thus new genetic markers involved in the pathogenesis of DN [9]. As biopsy material suitable for analysis was hard to find through the original foreseen sources, Partner 3 had to find other sources and finally 24 biopsies could be retrieved from Dutch Hospitals. After checking whether they were of suitable quality, kidney biopsies from 24 independent patients Figure 2. Image of a with DN were examined to create expression profiles to 48x48 Fluidigm lab-oncharacterise candidate genes. For expression profiling, RNA was chip labelled and hybridised to Illumina chips. The gene expression profiles were analyzed bioinformatically. For each biopsy the CNDP1 genotype was determined, as well as the mRNA transcription level of CNDP1 and compared to a panel of 3 household genes. Non supervised gene clustering of these expression profiles was performed and showed that they were all closely linked together. The expression level of CNDP1 has been correlated with 9 candidate genes co-upregulated with CNDP1, none of these genes has been suggested to play a role in diabetic nephropathy yet, and two of them are even yet unidentified genes. The results from expression profiling will be evaluated further, as all genes co-upregulated with CNDP1 are potential candidate genes for protection from diabetic nephropathy. One of the early symptoms of diabetic nephropathy is the development of albuminuria. Urinary Proteome analysis is a method to measure proteins excreted in the urine in very little amounts, even before albuminuria can be found. Analysis of the urinary proteome for the identification of a secretion pattern associated both with a specific genetic trait and a high-risk vascular profile of diabetic patients was performed. To this end urine from diabetes type 2 patients with and without diabetic nephropathy was collected and analysed using capillary electrophoresis coupled to mass spectrometry (CE-MS). When examining urine from the patients in the case-control trial, already existing classification patterns, e.g. for diabetes [10], chronic kidney disease and diabetic nephropathy [11] were applied in a blinded fashion, and after unblinding accuracy of classification was assessed using an in-house software of mosaiques Diagnostics. Classification of subjects in the respective groups (Diabetes yes/no, chronic kidney disease yes/no and diabetic nephropathy yes/no) was accurate, showing a sensitivity of 98.6% for diabetes classification, specificity and sensitivity values of 97.1 and 88.2 % for the chronic kidney disease classification and Classification performance for diabetic nephropathy resulted in an AUC value of 0.966. Patients from previously performed therapy trials with Irbesartan, treated either in a longitudinal fashion with 300 mg [12] or undergoing high-dose treatment [13] were also evaluated. It could be demonstrated that the therapy success with 300mg Irbesartan intake over a period of one year can be proven with the use of proteomic CE-MS analysis. Furthermore, in urine from patients participating in the longitudinal trial, peptides showing improvement of kidney status of microalbuminuric type 2 diabetic patients could be identified. In the patients on high dose Irbesartan, eight potential biomarkers showed a trend to decrease in a linear and dose dependent manner from microalbuminuric to treated (300,600,900 mg respectively) to normoalbuminuric type 2 diabetic patients. The fact that four of these eight identified peptides are uromodulin fragments indicates altered excretion of uromodulin at the loop of Henle associated with Irbesartan treatment. 6 Due to the late availability of the complete genetic data and the complete clinical data, analysis of specific secretion patterns associated with a specific genetic trait or a high-risk vascular profile are ongoing. The Assessment of biomarkers of protein glycation and oxidative stress as prognostic factors was addressed in different ways. Partner 10 measured markers of protein glycation in plasma and urine of diabetic patients with and without diabetic nephropathy as well as patients undergoing Irbesartan treatment. Manuscripts on those findings are in preparation at the moment. The presence of diabetic nephropathy did not produce marked changes in protein damage markers in plasma protein. Rather, urinary outputs of glycation adducts, FL and AGEs, and the oxidation marker NFK were increased in diabetic nephropathy. This suggest patient with diabetic nephropathy are suffering increased early and advanced glycation and oxidation in tissues rather than in plasma. Exploration of the association between biomarkers and response to treatment: Partner 10 also studied the effect of angiotensin receptor blocker Irbesartan on protein damage markers in type 2 diabetic patients with early stage nephropathy (microalbuminuria). Irbesartan therapy has tightened the glomerular filter and decreased the clearance of plasma protein. Protein damage markers that increased in plasma protein all increased to the same proportionate extent and this is reflecting decreased clearance of plasma protein. The markers that were unchanged and decreased indicate that Irbesartan therapy is probably decreasing protein damage of these types in plasma. This is mostly protein damage by dicarbonyl glycation – markers formed by plasma protein glycation with glyoxal, methylglyoxal and 3-deoxyglucosone, and protein oxidation (MetSO) and nitration (3-NT). It was planned to develop a risk model on the basis of the findings from the re-evaluation of previously proposed genetic variants, this objective could not be reached as no significant association could be found. However, urinary proteomics seems to represent a feasible way for diagnosis of diabetic nephropathy. There were a couple of other, not yet mentioned, important findings of PREDICTIONS. Partner 3 performed genetic association analysis on ESRD cohorts, an association with multiple leucine repeats in the CNDP1 gene was significantly associated with the risk of developing ESRD in patients with chronic glomerulonephritis (p=0.0006) and with renal vascular disease (p=0.011) as a primary cause for developing ESRD. In an animal study, diabetic male Sprague-Dawley rats were unilaterally nephrectomized and either treated with Carnosine (C), Lisinopril (L), or both (Mix). Controls were untreated, diabetic (STZ) rats. An Add-on therapy using Carnosine to the standard therapy with ACE-Inhibitors in this model diminishes albumin excretion, prevents cataract formation and improves glucose reabsorption. The data on DN-specific urine-peptides and the results of the in vitro studies have added to present knowledge on the role of TGF-β and Extra-cellular Matrix accumulation in DN. We postulated that high glucose in combination with low carnosine levels causes elevated TGF-β expression and activation of ALK5. This increases ECM assembly. An interim model of this is depicted in figure 3. 7 Increased collagen transcription might play a role, but reduced breakdown of collagens by proteases such as MMP9 is a major cause of the ECM accumulation. The genetic analysis of MMP9 (WP2) has confirmed genetic association of the MMP9 microsatellite with DN, although only at the nominal level (p=0.02). This mechanistic approach was used to identify further genes. MMP9, which has been suggested earlier to be associated with diabetic nephropathy was found to be significant on the nominal High glucose combined with low carnosine levels Elevated TGF-ß expression and activation of ALK5 pathway - Increased collagen transcription and ECM assembly, - Alternative splicing of ECM transcrips into altered ECM molecules with a reduced susceptibility to MMP-mediated degradation, - Inhibition of matrix proteases (e.g. MMP2 and MMP9) by TIMPs - Increased affinity of ECM receptors (integrins). Reduced turnover of collagens, excessive accumulation of ECM Figure 3. Interim model for TGF-β induced glomerulosclerosis glomerulosclerosis level (p=0.02), confirming these findings. MMP9 functional variants can therefore be considered risk factors in diabetic nephropathy. In conclusion, PREDICTIONS has approached diabetic nephropathy in type 2 diabetic patients from various sides, including genetic, biochemical and proteomic markers as well as mechanistic models. The contractors have succeeded in identifying potential new biomarkers for diabetic nephropathy and its different stages. Further detailed research is necessary to evaluate the identified markers. 8 Contractors: Partner 1a: Prof. Dr. Bart Janssen (Co-ordinator) Formerly: Institute of Human Genetics,University of Heidelberg Now: Service XS, Plesmanlaan 1d, 2333BZ Leiden Tel. +49-6221-5639568; E-mail: b.janssen@servicexs.com Partner 1b: Prof. Dr. Benito Yard Universitätsmedizin Mannheim, 68135 Mannheim, Germany Tel. +49 621 383 2340; Email: benito.yard@umm.de Partner 2: Prof. Brigitte M. Winklhofer-Roob, M.D. The University of Graz: A-8010 Graz, Austria Tel. +43-316-380-5490; Email: brigitte.winklhoferroob@uni-graz.at Partner 3 : Dr. Emile De Heer Leiden University Medical Center, POB 9600, 2300 RC Leiden, The Netherlands, Tel. +31 71 526 6623; E-mail: e.de_heer@lumc.nl Partner 4: Prof. Dr. GJ Navis Groningen University Medical Center, Hanzeplein 1, Groningen, The Netherlands Tel. + 31-503612621/4441; E-mail: g.j.navis@int.umcg.nl Partner 5/Partner 10: Prof Paul J. Thornalley University of Warwick, University Hospital, Coventry CV2 2DX, U.K. Tel. +44 24 7696 8594; Email: P.J.Thornalley@warwick.ac.uk Partner 6: Prof. Dr. Ivan Rychlík Charles University at Prague, 3rd Medical Faculty, 10000 Prague 10, Czech Republic, Tel. +420-267102657; E-mail: rychlik@cesnet.cz Partner 7: Dr. Lise Tarnow Novo Nordisk (Steno Diabetes Center), DK-2820 Gentofte, Denmark Tel. +45 44 43 99 52; E-mail: ltar@steno.dk Partner 8: Prof Harald Mischak Mosaiques Diagnostics GmbH, Mellendorfer Str. 7-9, D-30625 Hannover, Germany Tel. +49-511-554744-15; E-Mail: mischak@mosaiques-diagnostics.com Partner 9: Dr. Marcus Woerwag Woerwag Pharma GmbH & Co. KG, 71034 Boeblingen, Germany Tel. 07031/6204-13; E-mail: Heidrun.Gaertner@woerwagpharma.de 9 References: 1. Janssen, B., et al., Carnosine as a protective factor in diabetic nephropathy: association with a leucine repeat of the carnosinase gene CNDP1. Diabetes, 2005. 54(8): p. 2320-7. 2. Freedman, B.I., et al., A leucine repeat in the carnosinase gene CNDP1 is associated with diabetic end-stage renal disease in European Americans. Nephrol Dial Transplant, 2007. 22(4): p. 1131-5. 3. Zschocke, J., et al., Allelic variation in the CNDP1 gene and its lack of association with longevity and coronary heart disease. Mech Ageing Dev, 2006. 127(11): p. 817-20. 4. Riedl, E., et al., A CTG polymorphism in the CNDP1 gene determines the secretion of serum carnosinase in Cos-7 transfected cells. Diabetes, 2007. 56(9): p. 2410-3. 5. Tanaka, N., et al., Association of solute carrier family 12 (sodium/chloride) member 3 with diabetic nephropathy, identified by genome-wide analyses of single nucleotide polymorphisms. Diabetes, 2003. 52(11): p. 2848-53. 6. Ng, D.P., et al., Genetic variation at the SLC12A3 locus is unlikely to explain risk for advanced diabetic nephropathy in Caucasians with type 2 diabetes. Nephrol Dial Transplant, 2008. 23(7): p. 2260-4. 7. Kiechl, S., et al., Toll-like receptor 4 polymorphisms and atherogenesis. N Engl J Med, 2002. 347(3): p. 185-92. 8. Rudofsky, G., Jr., et al., Asp299Gly and Thr399Ile genotypes of the TLR4 gene are associated with a reduced prevalence of diabetic neuropathy in patients with type 2 diabetes. Diabetes Care, 2004. 27(1): p. 179-83. 9. Baelde, H.J., et al., Reduction of VEGF-A and CTGF expression in diabetic nephropathy is associated with podocyte loss. Kidney Int, 2007. 71(7): p. 637-45. 10. Snell-Bergeon, J.K., et al., Evaluation of urinary biomarkers for coronary artery disease, diabetes, and diabetic kidney disease. Diabetes Technol Ther, 2009. 11(1): p. 1-9. 11. Rossing, K., et al., Urinary proteomics in diabetes and CKD. J Am Soc Nephrol, 2008. 19(7): p. 1283-90. 12. Parving, H.H., et al., The effect of irbesartan on the development of diabetic nephropathy in patients with type 2 diabetes. N Engl J Med, 2001. 345(12): p. 870-8. 13. Rossing, K., et al., Enhanced renoprotective effects of ultrahigh doses of irbesartan in patients with type 2 diabetes and microalbuminuria. Kidney Int, 2005. 68(3): p. 1190-8. 14. Rabbani, N., et al., High-dose thiamine therapy for patients with type 2 diabetes and microalbuminuria: a randomised, double-blind placebo-controlled pilot study. Diabetologia, 2009. 52(2): p. 208-12. 10 2. Dissemination and use - Results from the benfotiamine trial: Since several years, benfotiamine is known as a pathogenetically based treatment option in diabetic complications, because it inhibits four noxious glucose metabolite pathways. Whereas several clinical studies on the efficacy in diabetic neuropathy were performed, clinical experiences with benfotiamine in diabetic complications like nephropathy, retinopathy or cardiovascular disturbances were lacking. Therefore, the benfotiamine trial as part of the PREDICTIONS project was the first clinical study of this compound on diabetic nephropathy. The goal of the study, to demonstrate a beneficial effect of benfotiamine in patients under optimal basic treatment of microalbuminuria (i.e. patients under ACE inhibitors or angiotensin antagonists) is a real challenge, because this basic treatment usually is very effective to decrease microalbuminuria. Because this trial is the first study in this indication, no information was available on patient characteristics especially on renal parameters. Therefore, patient number calculation was difficult to perform. However, this pilot study within the PREDICTIONS project will deliver data on relevant renal parameters as base for a following trial, even if the results do not meet the expectations (i.e. a beneficial effect of benfotiamine). This is a pre-requisite for further clinical development of a substance with very good tolerability in an indication with important impact on the quality of life of the patients and socio-economic burden of European communities by Wörwag Pharma. The results of this trial are expected in the summer of 2009. Meanwhile, a small pilot study [14] with water soluble thiamine in patients with diabetic nephropathy confirmed the hypothesis, that vitamin B1 might be helpful in this disease. These results stress the importance of further studies on this indication and development of appropriate medicinal drugs containing vitamin B1 or derivatives like benfotiamine. - Proteomic analysis with CE-MS: Proteomic analysis with CE-MS is useful for the early diagnosis and prognosis of diabetic nephropathy. Mosaiques diagnostics GmbH has already patented the biomarkers for diabetic nephropathy and has already marketed this in vitro diagnostic (IVD) based on multidimensional proteome analysis of the biomarkers identified in the project. Marketing accomplished via DiaPat GmbH, a subsidiary of Mosaiques Diagnostics, which already markets IVD based on proteome analysis for bladder and prostate cancer, as well as several renal diseases. Further, Mosaiques diagnostics plans to market the use of this diagnostic biomarker pattern in clinical trials (Pharmaceutical industry being the customer), which would result in better stratification of patients/improved inclusion criteria based on proteome pattern, as well as non-invasive and early detection of therapeutic benefits, but also potential side effects in these trials. 11