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Early prediction of kidney graft function may assist clinical management, and for this, reliable non-invasive biomarkers are needed. We evaluated endotrophin (ETP), a novel non-invasive biomarker of collagen type VI formation, as a prognostic marker in kidney transplant recipients. ETP levels were measured with the PRO-C6 ELISA in the plasma (P-ETP) of 218 and urine (U-ETP/Cr) of 172 kidney transplant recipients, one (D1) and five (D5) days, as well as three (M3) and twelve (M12) months, after transplantation. P-ETP and U-ETP/Cr at D1 (P-ETP AUC = 0.86, p < 0.0001; U-ETP/Cr AUC = 0.70, p = 0.0002) were independent markers of delayed graft function (DGF) and P-ETP at D1 had an odds ratio of 6.3 (p < 0.0001) for DGF when adjusted for plasma creatinine. The results for P-ETP at D1 were confirmed in a validation cohort of 146 transplant recipients (AUC = 0.92, p < 0.0001). U-ETP/Cr at M3 was negatively associated with kidney graft function at M12 (p = 0.007). This study suggests that ETP at D1 can identify patients at risk of delayed graft function and that U-ETP/Cr at M3 can predict the future status of the allograft. Thus, measuring collagen type VI formation could aid in predicting graft function in kidney transplant recipients.

BACKGROUND: AKI involves a rapid decrease in kidney function that may be associated with structural damage. Early markers predicting AKI are emerging, but tools to assess patients’ long-term health risks after AKI are still lacking. Endotrophin (ETP) is a bioactive molecule released during the formation of collagen type VI. We evaluated the potential of circulating ETP as a prognostic biomarker of adverse outcomes after AKI. METHODS: We measured ETP in plasma samples collected 1 year after an episode of AKI, using the PRO-C6 ELISA in 801 patients (393 patients with AKI and 408 controls) from the prospective AKI Risk in Derby (ARID) study (ISRCTN25405995), who were then followed until year 3. Kidney disease progression was defined as ≥25% decline in eGFR combined with a decline in CKD stage. RESULTS: ETP levels were significantly higher in the AKI group compared with controls (P

Peptide receptor radionuclide therapy (PRRT) is a treatment for neuroendocrine tumours (NET). Renal impairment is a known side effect due to kidney fibrosis. We investigated the association between novel specific fibrosis markers and kidney function following PRRT. We included 38 patients who had all finished PRRT. In serum and urine, we analysed levels of three different fibrosis markers, PRO-C6 (type VI collagen formation), PRO-C3 (type III collagen formation) and C3M (type III collagen degradation). We determined kidney function by the 51Cr-EDTA plasma clearance. We used Wilcoxon rank sum test and Spearman's rank correlation to evaluate the association between the fibrosis markers and kidney function. We included 38 NET patients, 25 small-intestinal NET, 6 pancreatic NET, 2 pulmonary NET and 5 other types of NET. Median age was 69 years (IQR: 61-73). Median time from last PRRT to inclusion was 8 months (IQR: 3-20). We found significantly increased levels of serum PRO-C6 (p = .007) and urinary PRO-C6 (p = .033) and significantly decreased levels of urinary C3M (p = .035) in patients with impaired kidney function. Further, we observed a negative association between serum PRO-C6 and kidney function (rho = -0.33, p = .04) and a positive association between urinary C3M and kidney function (rho = 0.37, p = .02). We showed an association between the three fibrosis markers, serum PRO-C6, urinary PRO-C6 and urinary C3M and kidney function. These markers may help to improve the understanding of potential pathological tissue turnover and potentially improve monitoring of kidney function after PRRT in NET patients.

OBJECTIVE We investigated endotrophin, a profibrotic signaling molecule reflecting collagen VI formation, in serum and urine as risk marker for complications to type 2 diabetes. RESEARCH DESIGN AND METHODS Endotrophin was measured in 774 individuals with type 2 diabetes. Outcomes included a composite kidney end point, first major adverse cardiovascular event (MACE), mortality, progression of albuminuria, incident heart failure, and sight-threatening eye disease. Adjusted Cox proportional hazards models were applied. RESULTS Doubling of serum endotrophin was associated with the kidney end point (n = 49; hazard ratio 1.80 [95% CI 1.13–2.87]), first MACE (n = 66; 1.54 [1.04–2.28]), mortality (n = 156; 1.69 (1.31–2.19]), and incident heart failure (n = 42; 1.63 [1.02–2.60]). A doubling of urine endotrophin was associated with progression of albuminuria (n = 85; 1.20 [1.04–1.39]). CONCLUSIONS Serum endotrophin was a risk marker for mortality and kidney and cardiovascular complications in type 2 diabetes. Urine endotrophin was a marker for albuminuria progression.

Background & Aims Serum microRNA (miRNA) levels are known to change in non-alcoholic fatty liver disease (NAFLD) and may serve as useful biomarkers. This study aimed to profile miRNAs comprehensively at all NAFLD stages. Methods We profiled 2,083 serum miRNAs in a discovery cohort (183 cases with NAFLD representing the complete NAFLD spectrum and 10 population controls). miRNA libraries generated by HTG EdgeSeq were sequenced by Illumina NextSeq. Selected serum miRNAs were profiled in 372 additional cases with NAFLD and 15 population controls by quantitative reverse transcriptase PCR. Results Levels of 275 miRNAs differed between cases and population controls. Fewer differences were seen within individual NAFLD stages, but miR-193a-5p consistently showed increased levels in all comparisons. Relative to NAFL/non-alcoholic steatohepatitis (NASH) with mild fibrosis (stage 0/1), 3 miRNAs (miR-193a-5p, miR-378d, and miR378d) were increased in cases with NASH and clinically significant fibrosis (stages 2–4), 7 (miR193a-5p, miR-378d, miR-378e, miR-320b, miR-320c, miR-320d, and miR-320e) increased in cases with NAFLD activity score (NAS) 5–8 compared with lower NAS, and 3 (miR-193a-5p, miR-378d, and miR-378e) increased but 1 (miR-19b-3p) decreased in steatosis, activity, and fibrosis (SAF) activity score 2–4 compared with lower SAF activity. The significant findings for miR-193a-5p were replicated in the additional cohort with NAFLD. Studies in Hep G2 cells showed that following palmitic acid treatment, miR-193a-5p expression decreased significantly. Gene targets for miR-193a-5p were investigated in liver RNAseq data for a case subgroup (n = 80); liver GPX8 levels correlated positively with serum miR-193a-5p. Conclusions Serum miR-193a-5p levels correlate strongly with NAFLD activity grade and fibrosis stage. MiR-193a-5p may have a role in the hepatic response to oxidative stress and is a potential clinically tractable circulating biomarker for progressive NAFLD. Lay summary MicroRNAs (miRNAs) are small pieces of nucleic acid that may turn expression of genes on or off. These molecules can be detected in the blood circulation, and their levels in blood may change in liver disease including non-alcoholic fatty liver disease (NAFLD). To see if we could detect specific miRNA associated with advanced stages of NAFLD, we carried out miRNA sequencing in a group of 183 patients with NAFLD of varying severity together with 10 population controls. We found that a number of miRNAs showed changes, mainly increases, in serum levels but that 1 particular miRNA miR-193a-5p consistently increased. We confirmed this increase in a second group of cases with NAFLD. Measuring this miRNA in a blood sample may be a useful way to determine whether a patient has advanced NAFLD without an invasive liver biopsy., Graphical abstract, Highlights • Serum miRNA was sequenced in 183 NAFLD cases of varying severity and 10 population controls. • Plasma levels of miR-193a-5p were significantly increased in patients with advanced fibrosis, high NAS scores, or high SAF scores. • Other miRNAs including miR378d and miR378e were also significantly increased in certain comparisons. • The findings for miR-193a-5p were replicated in a cohort of 372 additional NAFLD cases.

There is an unmet need for high-quality liquid biomarkers that can safely and reproducibly predict the stage of fibrosis and the outcomes of chronic liver disease (CLD). The requirement for such markers has intensified because of the high global prevalence of diseases such as non-alcoholic fatty liver disease (NAFLD). In particular, there is a need for diagnostic and prognostic tools, as well as predictive biomarkers that reflect the efficacy of interventions, as described by the BEST criteria (Biomarkers, EndpointS, and other Tools Resource). This review covers the various liver collagens, their functional role in tissue homeostasis and delineates the common nomenclature for biomarkers based on BEST criteria. It addresses the common confounders affecting serological biomarkers, and describes defined collagen epitope biomarkers that originate from the dynamic processes of extracellular matrix (ECM) remodelling during liver injury.

Background Renal fibrosis is the hallmark of chronic kidney disease (CKD) and is characterized by an imbalanced extracellular matrix remodelling. Endotrophin (ETP) is a signalling molecule released from collagen type VI (COL VI). ETP can be measured by the PRO-C6 assay, which quantifies the levels of COL VI formation. ETP levels were previously associated with mortality and disease progression in patients with CKD. We hypothesized that serum and urinary ETP levels correlate with the degree of interstitial fibrosis in kidney biopsies from patients with immunoglobulin A nephropathy (IgAN) and patients with anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). Methods We examined a cohort of 49 IgAN and 47 AAV patients. A validation cohort of 85 IgAN patients was included. ETP was measured in serum (S-ETP) and urine (U-ETP/Cr) samples, taken on the same day before renal biopsy was performed, using the enzyme-linked immunosorbent assay PRO-C6. The biopsies were evaluated for interstitial fibrosis and tubular atrophy according to the Banff and MEST-C scores. Results S-ETP and U-ETP/Cr levels correlated with kidney function, increased CKD severity, correlated with the extent of interstitial fibrosis and gradually increased with increasing degree of interstitial fibrosis and tubular atrophy. ETP outperformed the known fibrosis biomarker Dickkopf-3 for discrimination of patients with high fibrotic burden. The association of S-ETP and U-ETP/Cr with the level of kidney fibrosis was confirmed in the validation cohort. Conclusions We demonstrated that high levels of circulating and excreted ETP are not only indicative of lower kidney function, but also reflect the burden of fibrosis in the kidneys.

BACKGROUND & AIMS The development of accurate non-invasive tests to detect and measure the extent of fibrosis and disease activity in patients with non-alcoholic steatohepatitis (NASH) - the progressive phenotype of non-alcoholic fatty liver disease (NAFLD) - is of great clinical importance. Herein, we aimed to validate the performance of PRO-C3 and ADAPT for the detection of moderate/severe fibrosis within the CENTAUR screening population. METHODS PRO-C3 was assessed in plasma from the screening population of the phase IIb CENTAUR study (NCT02217475) in adults with NASH and liver fibrosis. The relation between PRO-C3 and histologic features of NASH was evaluated, as well as the demographics of patients with high and low levels of PRO-C3. The diagnostic ability of PRO-C3, as a standalone marker or incorporated into ADAPT, to identify patients with F≥2 and NASH was estimated using receiver-operating characteristic analysis and logistic regression models. RESULTS A total of 517 individuals with matched biopsy and PRO-C3 measurements were included. Patients with PRO-C3 levels ≥20.2 ng/ml showed increased levels of insulin, HOMA-IR, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, and platelet count compared to patients with low PRO-C3 (p

Objectives There is a need for precision medicine and an unspoken promise of an optimal approach for identification of the right patients for value-based medicine based on big data. However, there may be a misconception that measurement of proteins is more valuable than measurement of fewer selected biomarkers. In population-based research, variation may be somewhat eliminated by quantity. However, this fascination of numbers may limit the attention to and understanding of the single. This review highlights that protein measurements (with collagens as examples) may mean different things depending on the targeted epitope – formation or degradation of tissues, and even signaling potential of proteins. Design and Methods PubMed was searched for collagen, neo-epitope, biomarkers. Results: Ample examples of assays with specific epitopes, either pathological such as HbA1c , or domain specific such as pro-peptides, which total protein arrays would not have identified were evident. Conclusions We suggest that big data may be considered as the funnel of data points, in which most important parameters will be selected. If the technical precision is low or the biological accuracy is limited, and we include suboptimal quality of biomarkers, disguised as big data, we may not be able to fulfill the promise of helping patients searching for the optimal treatment. Alternatively, if the technical precision of the total protein quantification is high, but we miss the functional domains with the most considerable biological meaning, we miss the most important and valuable information of a given protein. This review highlights that measurements of the same protein in different ways may provide completely different meanings. We need to understand the pathological importance of each epitope quantified to maximize protein measurements.

Background and Aims Accumulation of extracellular matrix (ECM) proteins is a hallmark of kidney fibrosis, which can lead to altered tissue homeostasis, kidney failure, and ultimately death. Many different cell types are involved in this process, but fibroblasts are the main source of ECM proteins such as collagen type I (COL I), III (COL III), and VI (COL VI). Recently, it was suggested that a fragment of COL VI, released during collagen maturation, is a bioactive molecule (endotrophin; ETP) with signaling potential, indicating that collagens are not just passive structural proteins. In this study, we investigated the effect of different pro-fibrotic stimulants on COL VI production and the effect of ETP itself on human kidney fibroblasts in the scar-in-a-jar (SiaJ) cell model. Method Cells were seeded in 48-well plates at 30.000 cells/well and incubated for 24h in DMEM + 10% FBS for adherence. Cells were then starved by incubating them for further 24h in DMEM + 0.4% FBS. To induce fibrogenesis, fresh medium was added at day 0 with 225/150 mg/mL Ficoll 70/400 and 1% ascorbic acid, containing either 7-, 0.7-, or 0.07 nM PDGF-AA, 8-, 0.8-, or 0.08 nM PDGF-BB, 4-, 0.4-, or 0.04 nM PDGF-CC, 7-, 0.7-, or 0.07 nM PDGF-DD, 0.9-, or 0.09 nM CTGF, 0.02 nM TGF-β or 30 nM ETP. Medium was changed and collected on days 3, 6, 10, and 13. Biomarkers of COL I (PRO-C1), III (PRO-C3), and VI (PRO-C6) formation were assessed in the medium by enzyme-linked immunosorbent assays developed at Nordic Bioscience. Results The stimulation of kidney fibroblasts with PDGF-AA, -BB, -CC, and -DD caused an increase in PRO-C6 compared to the unstimulated cells at every time point (P Conclusion The production of COL VI, an important mediator of fibrosis and inflammation through its bioactive fragment endotrophin, shows a differential expression after stimulation of kidney fibroblasts with different pro-fibrotic growth factors. Interestingly, members of the PDGF family induced COL VI production, whereas CTGF and TGF-β did not. Moreover, we confirmed that ETP itself could stimulate kidney fibroblasts to produce more ECM proteins; hence COL VI may self-perpetuate fibrosis. This SiaJ model, combined with ECM formation biomarkers, could be used to elucidate the mechanisms behind acute and sustained matrix production profiles in vivo.

Background and Aims Autosomal dominant polycystic kidney disease (ADPKD) is an inherited kidney disease characterized by development and growth of cysts leading to loss of kidney function. In patients with ADPKD, fibrosis has been associated with the expansion of cysts and with an increased rate of progression to end-stage kidney disease (ESKD). Fibrosis is characterized by an imbalanced turnover of extracellular matrix (ECM) components such as collagens. Existing biomarkers of ADPKD have limited prognostic ability and the ECM can be a source of novel biomarkers of disease progression. In the current study, we investigated the cross-sectional association of collagen biomarkers with markers of disease severity in patients with ADPKD. Method Collagen type I, III and VI formation as well as collagen type III degradation were assessed with the PRO-C1, PRO-C3, PRO-C6 and C3M enzyme-linked immunosorbent assays (ELISAs). The four biomarkers were measured in serum from 311 patients with ADPKD from the DIPAK-1 (NCT01616927) study at baseline. Biomarker levels were compared with levels in serum of 38 healthy controls matched for sex and age. The difference between the ADPKD and the control group was assessed by Kruskal-Wallis test. The association of the collagen biomarkers with kidney function (eGFR) and height adjusted total kidney volume (htTKV) was assessed with uni- and multivariate regression analysis. Data was log-transformed if appropriate. Results Biomarker levels in the ADPKD patients (age, median (IQR): 49 (43-54) years; sex: 53% female) were compared with levels in matched healthy controls (age, median (IQR): 49 (43-56) years; sex: 53% female). In patients with ADPKD both PRO-C3 and PRO-C6 levels were increased compared to healthy controls (ADPKD vs controls, PRO-C3 median (IQR): 12.8 (10.5-15.8) vs 8.4 (7.5-10.1) ng/mL; P Conclusion While biomarkers of tubulointerstitial fibrosis (PRO-C3 and PRO-C6) were elevated in circulation in ADPKD patients, possibly reflecting an elevated fibrosis activity in the kidneys, levels of collagen type I formation (PRO-C1) were lower, possibly reflecting a suppressed bone turnover previously observed in patients with ADPKD. Both PRO-C3 and PRO-C6 showed an independent association with eGFR, but not with htTKV, when adjusting for known determinants of disease severity. Such biomarkers deserve further investigation in this patient population, especially concerning their prognostic abilities, as fibrosis is acknowledged as a driving force in progression to ESKD.

Pulmonary fibrosis has been identified as a main factor leading to pulmonary dysfunction and poor quality of life in post-recovery Severe Acute Respiratory Syndrome (SARS) survivor’s consequent to SARS-Cov-2 infection. Thus there is an urgent medical need for identification of readily available biomarkers that in patients with SARS-Cov-2 infection are able to; (1) identify patients in most need of medical care prior to admittance to an intensive care unit (ICU), and; (2) identify patients post-infection at risk of developing persistent fibrosis of lungs with subsequent impaired quality of life and increased morbidity and mortality. An intense amount of research have focused on wound healing and Extracellular Matrix (ECM) remodelling of the lungs related to lung function decline in pulmonary fibrosis (PF). A range of non-invasive serological biomarkers, reflecting tissue remodelling, and fibrosis have been shown to predict risk of acute exacerbations, lung function decline and mortality in PF and other interstitial lung diseases (Sand et al. in Respir Res 19:82, 2018). We suggest that lessons learned from such PF studies of the pathological processes leading to lung function decline could be used to better identify patients infected with SARS-Co-V2 at most risk of acute deterioration or persistent fibrotic damage of the lung and could consequently be used to guide treatment decisions.

Fibrosis is often heterogeneously distributed, and classical biopsies do not reflect this. Noninvasive methods for renal fibrosis have been developed to follow chronic kidney diseases (CKD) and to monitor anti-fibrotic therapy. In this study, we combined two approaches to assess fibrosis regression following renal ischemia-reperfusion injury (IRI): magnetic resonance imaging (MRI) and noninvasive extracellular matrix (ECM) biomarkers. MRI was used to evaluate fibrosis in bilateral IRI in rats after reperfusion at 7, 14, and 21 days. This was performed with 1HT1 and T2* mapping, dynamic contrast-enhanced (DCE)-MRI, and chemical shift imaging (CSI)-23Na. The degradation of laminin gamma-1 chain (LG1M) and type III collagen (C3M) was measured in urine and plasma. Fibrosis was analyzed in tissue using fibronectin (FN) and alpha-smooth muscle actin (α-SMA) using quantitative polymerase chain reaction qPCR and western blotting. We found increased fibrosis 7 days after reperfusion, which dropped to sham levels after 21 days. Single kidney glomerular filtration rate (skGFR), perfusion (DCE-MRI), and total 23Na kidney content correlated positively with fibrotic markers FN and α-SMA as well as noninvasive LG1M and C3M. We showed that novel MRI protocols and ECM markers could track fibrogenic development. This could give rise to a multi-parametric practice to diagnose and assess fibrosis whilst treating kidney disease without using invasive methods.

As a result of the aging population and obesity, diabetes is a major, increasing public health issue approaching global epidemic proportions. It is well known that patients with diabetes have higher levels of inflammation and that the underlying pathology contributes to blood vessel damage resulting in cardiovascular complications. Recently it was suggested that a fragment of collagen type VI (COL VI), released during deposition, is in fact a novel hormone (endotrophin; ETP), suggesting the extracellular matrix (ECM) to be involved in the regulation of type 2 diabetes. In this study, we investigated the association of ETP (measured by the PRO-C6 ELISA) with diabetes and mortality in a large prospective cohort. From 1999-2001, 5855 postmenopausal women with a mean±SD age of 71±6.5 were included in the Prospective Epidemiological Risk Factor study, and visits were planned according to a pre-defined protocol. The diagnoses for diabetes and mortality were extracted from the Danish Health Registries. We measured ETP in serum of 5608 women at baseline (samples collected from 1999-2001). ETP levels were measured in 2016. ETP levels were significantly elevated in women who died (p In conclusion, we demonstrate that the hormone ETP, a biomarker also reflecting COL VI deposition, was increased in serum of postmenopausal women with diabetes compared to healthy women. In addition, we show that ETP was associated with mortality, suggesting that turnover of the ECM is very important in metabolic disorders. Disclosure A. Møller: None. D.G.K. Rasmussen: Employee; Self; Nordic Bioscience. M.A. Karsdal: Stock/Shareholder; Self; Nordic Bioscience. C. Christiansen: None. L.M. Staunstrup: None. C.L. Bager: None. Funding Danish Research Foundation

Extracellular matrix (ECM) remodeling is a hallmark of the pathology of gastrointestinal disorders. Collagen type VI (COL6) is produced by fibroblasts, and the COL6 α3-chain has shown to be elevated in patients with ulcerative colitis (UC), Crohn’s disease (CD) and colorectal cancer (CRC). Measuring COL6α3 in serum may therefore have potential as a biomarker for gastrointestinal disorders. The aims of this study were to develop and validate a competitive ELISA targeting a specific neo-epitope of COL6α3 and evaluate its associations with the gastrointestinal disorders UC, CD and CRC, in comparison to healthy controls. A monoclonal antibody was raised against a matrix metalloproteinase-2 and -9 specific cleavage site of COL6α3 (C6Mα3) and employed in a competitive enzyme-linked immunosorbent assay (ELISA). The assay was developed and technically validated. Levels of C6Mα3 were measured in serum from patients with UC (n = 58), CD (n = 44) and CRC (n = 39) and compared to healthy controls (n = 32). The levels of C6Mα3 were elevated in patients with UC, CD and CRC patients compared to healthy controls (all p

Background Tubulointerstitial fibrosis is a major pathological feature in chronic kidney disease (CKD) and collagen type III (COL3) is a major component of the renal fibrotic scar. We hypothesized that a dysregulated turnover of COL3 is an important determinant of CKD progression. We assessed the relationship between fragments reflecting active formation (PRO-C3) and degradation (C3M) of COL3 and CKD disease progression and mortality in a prospective cohort of CKD patients. Methods We measured PRO-C3 and C3M in urine (uPRO-C3 and uC3M) and serum (sPRO-C3 and sC3M) of 500 patients from the Renal Impairment in Secondary Care study. Disease progression was defined as a decline in estimated glomerular filtration rate >30% or the start of renal replacement therapy within 12 and 30 months. Results Levels of uC3M/creatinine decreased, whereas levels of uPRO-C3/creatinine and sPRO-C3 increased with increasing CKD stage. uC3M/creatinine was inversely and independently associated with disease progression by 12 months {odds ratio [OR] 0.39 [95% confidence interval (CI) 0.18–0.83]; P = 0.01 per doubling of uC3M/creatinine} with development of end-stage renal disease [hazard ratio (HR) 0.70 (95% CI 0.50–0.97); P = 0.03 per doubling of uC3M/creatinine]. sPRO-C3 at baseline was independently associated with increased mortality [HR 1.93 (95% CI 1.21–3.1); P = 0.006 per doubling of sPRO-C3] and disease progression by 30 months [OR 2.16 (95% CI 1.21–3.84); P = 0.009 per doubling of sPRO-C3]. Conclusions Dynamic products of COL3 formation and degradation were independently associated with CKD progression and mortality and may represent an opportunity to link pathological processes with targeted treatments against fibrosis.

Background Maintenance of kidney function in kidney allografts remains a challenge, as the allograft often progressively develops fibrosis after kidney transplantation. Fibrosis is caused by the accumulation of extracellular matrix proteins like type I and III collagen (COL I and III) that replace the functional tissue. We assessed the concentrations of a neo-epitope fragment of COL III generated by matrix metalloproteinase-9 cleavage (C3M) in two rat models resembling the ischaemic injury taking place following kidney transplantation. Methods We measured C3M in urine (U-C3M) and plasma (P-C3M) samples of rats subjected to unilateral nephrectomy followed by sham operation (NTx) or ischaemia reperfusion injury (NTxIRI) as well as in rats subjected to bilateral ischaemia reperfusion injury (BiIRI). Levels of U-C3M were normalized to urinary creatinine and were correlated to plasma creatinine, blood urea nitrogen, messenger ribonucleic acid (mRNA) of markers of kidney injury, and mRNA and protein levels of markers of tissue repair and fibrosis. Results Levels of U-C3M were significantly elevated 7 days after ischaemia reperfusion in the NTxIRI. BiIRI animals showed higher levels of U-C3M after 7 and 14 days of reperfusion but not at 21 days. P-C3M did not change in any of the models. There was a significant correlation between U-C3M and mRNA levels of fibronectin, COL I alpha 1 chain (COL Ia1) and neutrophil gelatinase-associated lipocalin (NGAL), and protein levels of alpha smooth muscle actin (αSMA), fibronectin and COL III in NTxIRI but not in NTx animals. Levels of U-C3M increased significantly in the BiIRI animals subsequent to reperfusion, and mirrored the histological alterations. Furthermore, U-C3M was associated with the extent of fibrosis, and remained elevated even after plasma creatinine levels decreased. Conclusions These results demonstrate that degradation of COL III increases after ischaemia reperfusion injury, and that U-C3M may be a non-invasive marker of tissue repair and fibrosis in the ischaemic kidney.

Renal fibrosis is a hallmark of chronic kidney disease (CKD) caused by an imbalance between formation and degradation of extracellular matrix proteins. We investigated the collagen turnover profile of 81 non-dialysis CKD stage 2–5 patients by measuring peptides reflecting formation and degradation of collagen type (COL) I, III, IV, and VI. Based on the collagen turnover profile, we identified four clusters of patients. Cluster 1 contained one patient with prostate cancer, who had a distinct collagen turnover. The other clusters generally had severe (Cluster 2), moderate (Cluster 4), or mild CKD (Cluster 3). Cluster 4 patients were characterized by higher levels of COL III, COL IV, and COL VI (all p

OBJECTIVE Patients with type 1 diabetes (T1D) have a higher risk of developing chronic kidney disease, cardiovascular events (CVEs), and mortality than the general population. We hypothesized that two previously published biomarkers, namely PRO-C6, a biomarker of collagen type VI formation, and C3M, a biomarker of collagen type III degradation, may be associated with impaired renal function and have prognostic value for adverse renal, CVE, and mortality in patients with T1D. RESEARCH DESIGN AND METHODS PRO-C6 and C3M in serum (sPRO-C6, sC3M) and urine (uPRO-C6, uC3M) were measured by ELISA in 663 patients with T1D ranging from normoalbuminuric to macroalbuminuric. Association of the biomarkers with mortality, CVEs, heart failure, decline in estimated glomerular filtration rate (eGFR) ≥30%, and end-stage renal disease (ESRD) were tested in Cox proportional hazards models after log2 transformation and adjusted for relevant clinical characteristics. Hazard ratios (HRs) were reported per doubling of biomarker levels. RESULTS High levels of sPRO-C6 were independently associated with a higher risk of all-cause mortality (HR 2.26 [95% CI 1.31–3.87], P < 0.0031). There was an association with higher risk of CVEs (n = 94) and heart failure (n = 28) but not after adjustment (P ≥ 0.58). In relation to renal outcomes, adjusted sPRO-C6 was associated with a higher risk of eGFR decline ≥30% in T1D, with eGFR >45 and >30 mL/min/1.73 m2, and with a higher risk of ESRD (all P ≤ 0.03). Higher uPRO-C6 was associated with a lower risk of decline in eGFR. CONCLUSIONS In patients with T1D, higher sPRO-C6 was an independent predictor of both decline in eGFR and development of ESRD and of all-cause mortality. Higher uPRO-C6 was also associated with a lower risk of decline in eGFR.

The PRO-C6 assay, a reflection of collagen type VI synthesis, has been proposed as a non-invasive early biomarker of kidney fibrosis. We aimed to investigate cross-sectional and longitudinal associations between plasma and urine PRO-C6 and proven histological changes after kidney transplantation. The current study is a post-hoc analysis of 94 participants of the MECANO trial, a 24-month prospective, multicenter, open-label, randomized, controlled trial aimed at comparing everolimus-based vs. cyclosporine-based immunosuppression. PRO-C6 was measured in plasma and urine samples collected 6 and 24 months post-transplantation. Fibrosis was evaluated in biopsies collected at the same time points by Banff interstitial fibrosis/tubular atrophy (IF/TA) scoring and collagen staining (Picro Sirius Red, PSR), inflammation was evaluated by the tubulo-interstitial inflammation score (ti-score). Linear regression analyses were performed. Six-month plasma PRO-C6 was cross-sectionally associated with IF/TA score (Std. &beta, = 0.34), and prospectively with 24-month IF/TA score and ti-score (Std. &beta, = 0.24 and 0.23, respectively) (p &lt, 0.05 for all). No significant associations were found between urine PRO-C6 and any of the biopsy findings. Fibrotic changes and urine PRO-C6 behaved differentially over time according to immunosuppressive therapy. These results are a first step towards non-invasive fibrosis detection after kidney transplantation by means of collagen VI synthesis measurement, and further research is required.

Background: Patients with myocardial infarction (MI) and concurrent chronic obstructive pulmonary disease (COPD) are often undertreated with beta-blockers, however data on the temporal trends and risk factors for non-use of beta-blockers are limited. Aims: To investigate beta-blocker, aspirin and statin usage in patients with first-time MI and concurrent COPD from 1995 to 2015 and to determine risk factors for medication non-use. Methods: Nationwide cohort study using Danish registers. Results: Among 143,126 patients with first-time MI, 13,726 (9,6%) had concurrent COPD. COPD patients were older, and had more comorbidities and lower socioeconomic status. Beta-blockers were systematically underused in COPD, but the usage increased over time (Figure 1). Aspirin and statins were also underused in COPD, but to a lesser extent. In multivariate logistic regression, COPD was associated with a 2.6-fold increased risk of non-use of beta-blockers. Among COPD patients, risk factors for non-use were female sex, high age, frequent exacerbations, use of multiple inhaled medications, and concurrent asthma. In addition, high GOLD stage and dyspnea score were risk factors in a subanalysis. Conclusions: This large nationwide study showed that during 1995-2015 COPD patients with first-time MI were systematically undertreated with beta-blockers, and to a lesser extent aspirin and statins.

Introduction: Congestive heart failure (CHF) is a common comorbidity in COPD. Objectives: We investigated whether outpatients with COPD and CHF were treated with β-blockers and angiotensin converting enzyme inhibitors or angiotensin receptor blocker (ACEI/ARB) according to guidelines and compared to data on all Danish patients with CHF. Methods: Observational cohort study with data from the Danish Register of COPD, which covers all patients with COPD treated in Danish hospitals since 2008. Medication and diagnosis of CHF was determined at time of first outpatient visit for COPD though National Registers. Results: From a total of 46,630 outpatients with COPD, 7,251 (16%) patients were identified with CHF. Among these, the mean age was 74.3 years and mean FEV 1 48% of predicted value. 3,613 (57%) had severe COPD (GOLD class 3 + 4) and 2,983 (47%) had severe dyspnea (MRC score 4 - 5). In patients with both COPD and CHF, 52 % were prescribed β-blockers and 56% ACEI/ARB, which is significantly lower than the corresponding percentages among all Danish patients with CHF (89% for β-blockers and 92% for ACEI/ARB). Conclusions: This large study shows that outpatients with COPD and CHF are undertreated with β-blockers and ACEI/ARB, both according to guidelines and compared to the national average. Implementation of correct heart failure treatment is likely to improve prognosis of this vulnerable group of patients.

Background: Renal fibrogenesis is associated with increased ECM remodeling and release of collagen fragments in urine in progressive renal disease. We investigated the diagnostic value of urinary collagen degradation products in a proteinuria-driven fibrosis rat model with and without anti-fibrotic S1P-receptor modulator FTY720 treatment.Methods: Proteinuria was induced in male Wistar rats by Adriamycin (ADR) injection (n = 16). Healthy rats served as controls (n = 12). Six weeks post-injection, all underwent renal biopsy, and FTY720-treatment started in ADR-rats (n = 8) and controls (n = 6). Others remained untreated. Rats were sacrificed after 12 weeks. Collagen type I (C1M) and III (C3M) degradation fragments were measured in blood and urine using ELISA. Kidneys were stained for various inflammatory and fibrotic markers.Results: Six weeks post-injection proteinuria increased (versus controls, P Conclusions: These data displayed urinary collagen breakdown products as sensitive early markers of interstitial fibrosis, preceding histological fibrotic changes, which might replace the invasive renal biopsy procedure to assess fibrosis. Anti-fibrotic FTY720 intervention reduced some fibrotic markers without affecting collagen type III metabolism.

Natural cytokine-specific autoantibodies (c-aAb) have been measured in healthy and diseased individuals, and have been considered as both endogenous immune-regulators and pathogenic factors. Overall, the etiology and potential pathology of c-aAb are still undefined. To further characterize the sero-prevalence, predictors and consequences of high c-aAb levels, we performed the largest population-based study of c-aAb to date, using participants and epidemiological data from the Danish Blood Donor Study. Using a validated bead-based multiplex assay we assessed plasma levels of IL-1α, IL-6, IL-10, IFNα and GM-CSF-specific c-aAb in 8,972 healthy blood donors. Trace levels of at least one of the investigated c-aAb could be measured in 86% of the participants. The presence of high levels of potentially inhibitory c-aAb was generally associated with increasing age and male or female sex, depending on the c-aAb in question. A negative correlation between high levels of IL-6-specific c-aAb and plasma levels of C-reactive protein was observed, indicating cytokine-neutralizing levels of c-aAb in healthy blood donors. There was no substantial correlation between high levels of the five individual c-aAb investigated in this study. These data suggest that autoimmunity against endogenous cytokines is a relatively common phenomenon in healthy individuals, and that predictive factors for high, potentially neutralizing c-aAb levels vary depending on the cytokine in question, and may differ from predictors of general c-aAb presence.

A high level of extracellular matrix (ECM) turnover characterizes several lung diseases with fibrotic features. Type III collagen is one of the most abundant collagens in lung parenchyma, and cathepsins play a role in lung pathology, being responsible for tissue remodeling. In this study, we explore the diagnostic features of neo-epitope fragments of type III collagen generated by cathepsins that could reflect the pathological tissue turnover in patients with different diseases. A novel enzyme-linked immunosorbent assay (ELISA) measuring cathepsins B, L, S and K-generated type III collagen fragments (C3C) was developed for assessment in serum and plasma. The assay was biologically validated in serum from patients with chronic obstructive pulmonary disease (COPD). Serological levels of C3C were significantly elevated in patients with COPD compared to healthy controls (p = 0.0006). Levels of C3C in serum and heparin plasma of COPD patients had a highly significant correlation (R2 = 0.86, p

Scientific reports 7(1), 17328 (2017). doi:10.1038/s41598-017-17470-3, Published by Nature Publishing Group, London

Background: Patients with chronic kidney disease (CKD) have increased risk of development of endstage renal disease (ESRD) and early mortality. Fibrosis is the central pathogenic process in CKD and is caused by dysregulated extracellular matrix (ECM) remodeling. The laminin γ1 chain (LAMC1) is a core structural protein present in the basement membrane of several organs, including the kidneys. We hypothesized that dysregulation of LAMC1 remodeling could be associated with a higher risk of adverse clinical outcomes in patients with CKD. 'Methods: A novel immunoassay targeting LG1M, a specific MMP-9-generated neo-epitope fragment of LAMC1, was developed and used to measure the levels of the fragment in urine and serum from 492 patients from the Renal Impairment in Secondary Care (RIISC) study, a prospective cohort of patients with high-risk CKD. Patients were monitored for a median followup time of 3.5 years. Associations between serum and urine LG1M levels and progression of CKD at 12 months were assessed by a multivariable logistic regression model. The association with ESRD or mortality was assessed by Kaplan-Meier survival curves and Cox proportional hazards regression. Results: Forty-six (11%) of the 416 patients who reached 12-month follow-up had progression of CKD; during the study follow-up, 125 patients (25.4%) developed ESRD and 71 patients (14.4%) died. Serum and urine levels of LG1M correlated with baseline eGFR (r = -0.43, pConclusions: LG1M, a marker of basement membrane remodeling, is increased in serum and urine of patients with CKD and levels are associated with one-year disease progression, development of ESRD, and mortality.

Aim: Arterial stiffening reflects fragmentation and loss of elastin fibers and accumulation of stiffer collagen fibers in the media of large arteries. We evaluated associations between carotid-femoral pulse wave velocity (cfPWV) and a marker of collagen type VI formation (Pro-C6) and a marker of collagen type III degradation (C3M) in type 1 diabetes. Methods: Serum and urinary level of Pro-C6 and C3M was measured with ELISA in 634 patients with type 1 diabetes. cfPWV was assessed by the SphygmoCor device. We applied unadjusted and adjusted linear regression analyses. Adjustment included sex, age, mean arterial pressure, LDL cholesterol, smoking, HbA1c, eGFR and urinary albumin excretion rate. To adjust for urine output levels, the urinary markers were normalized for urinary creatinine. Results: Of the 634 patients, 349 (55%) were male, mean±SD age was 54.6±12.6 years and cfPWV 10.4±3.3 m/s. Higher serum and urinary level of Pro-C6 was associated with higher cfPWV in unadjusted models (p≤0.039), after adjustment only higher serum level remained significantly associated with higher cfPWV (β estimate per doubling: 0.47±0.21; p = 0.028). Lower urinary level of C3M was associated with higher cfPWV in the unadjusted model (p < 0.001), but significance was lost after adjustment (p = 0.44). Higher serum level of C3M was associated with higher cfPWV in the unadjusted model (p = 0.002), but significance was lost after adjustment (p = 0.34). Conclusion: In type 1 diabetes, higher serum levels of Pro-C6, a marker of collagen type VI formation, was associated with increased arterial stiffness. This observation could introduce a new target for therapeutic intervention.