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Jandl K, Mutgan AC, Eller K, Schaefer L, Kwapiszewska G. The basement membrane in the cross-roads between the lung and kidney. Matrix Biol 2021; 105:31-52. [PMID: 34839001 DOI: 10.1016/j.matbio.2021.11.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 11/05/2021] [Accepted: 11/18/2021] [Indexed: 12/23/2022]
Abstract
The basement membrane (BM) is a specialized layer of extracellular matrix components that plays a central role in maintaining lung and kidney functions. Although the composition of the BM is usually tissue specific, the lung and the kidney preferentially use similar BM components. Unsurprisingly, diseases with BM defects often have severe pulmonary or renal manifestations, sometimes both. Excessive remodeling of the BM, which is a hallmark of both inflammatory and fibrosing diseases in the lung and the kidney, can lead to the release of BM-derived matrikines, proteolytic fragments with distinct biological functions. These matrikines can then influence disease activity at the site of liberation. However, they are also released to the circulation, where they can directly affect the vascular endothelium or target other organs, leading to extrapulmonary or extrarenal manifestations. In this review, we will summarize the current knowledge of the composition and function of the BM and its matrikines in health and disease, both in the lung and in the kidney. By comparison, we will highlight, why the BM and its matrikines may be central in establishing a renal-pulmonary interaction axis.
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Affiliation(s)
- Katharina Jandl
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Otto Loewi Research Center, Department of Pharmacology, Medical University of Graz, Graz, Austria
| | - Ayse Ceren Mutgan
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Otto Loewi Research Center, Department of Physiology, Medical University of Graz, Graz, Austria
| | - Kathrin Eller
- Clinical Division of Nephrology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Liliana Schaefer
- Institute of Pharmacology and Toxicology, Goethe University, Frankfurt, Germany
| | - Grazyna Kwapiszewska
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria; Otto Loewi Research Center, Department of Physiology, Medical University of Graz, Graz, Austria; Institute for Lung Health (ILH), Giessen, Germany..
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Steubl D, Inker LA. How best to estimate glomerular filtration rate? Novel filtration markers and their application. Curr Opin Nephrol Hypertens 2019; 27:398-405. [PMID: 30063487 DOI: 10.1097/mnh.0000000000000444] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE OF REVIEW Chronic kidney disease is an increasing health burden. Estimating equations using serum concentrations of creatinine and cystatin C facilitate the assessment of kidney function as reflected in estimated glomerular filtration rate (eGFR). Reduced eGFR is associated with increased risk for numerous adverse outcomes and is an important aspect in many clinical situations. However, current equations are suboptimal in some clinical settings. The review focuses on approaches to improve the estimation of GFR and aims to familiarize the reader with the underlying methodological hypotheses how new markers could contribute to improve the overall performance of estimating equations. RECENT FINDINGS Low molecular weight proteins such as β-trace-protein and β-2-microglobulin, as well as newly discovered metabolites, show promise as new filtration markers, as they might be beneficial in populations in which creatinine or cystatin C are inaccurate. We propose that the combination of multiple novel markers, alone or in combination with creatinine, cystatin C or demographics, can potentially improve GFR estimation. For special populations such as dialysis patients, separate equations have been developed to estimate residual kidney function. SUMMARY Current GFR estimating equations are an essential part of routine clinical practice but have limitations. The use of multiple markers combined in a single equation appears to be the most promising approach. Future research is required to validate proposed equations in diverse populations.
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Affiliation(s)
- Dominik Steubl
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts, USA.,Abteilung für Nephrologie, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Lesley A Inker
- Division of Nephrology, Tufts Medical Center, Boston, Massachusetts, USA
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Yu D, Li HX, Liu Y, Ying ZW, Guo JJ, Cao CY, Wang J, Li YF, Yang HR. The Reference Intervals for Serum C-Terminal Agrin Fragment in Healthy Individuals and as a Biomarker for Renal Function in Kidney Transplant Recipients. J Clin Lab Anal 2016; 31. [PMID: 27638235 DOI: 10.1002/jcla.22059] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/31/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND C-terminal agrin fragment (CAF) has been shown to be a promising new biomarker for kidney function. The aim of this study was to verify the reference intervals for CAF in Chinese healthy adults and to assess the efficiency of CAF for monitoring renal function after transplantation. METHODS Serum samples were collected from 200 healthy adult subjects and 60 living donor kidney recipients before and on day 1, day 2 and at 6 months after transplantation. We measured serum CAF, creatinine, cystatin C and NGAL concentrations at each time. Estimated glomerular filtration rate (eGFR) was evaluated by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Reference intervals for CAF were determined at 2.5th and 97.5th percentiles. RESULTS Serum CAF concentrations were observed to be higher in females of old age groups while no significant differences were discovered in males between age groups. There were significant gender-related differences in CAF in old age groups (50-64 and ≥65 years). Serum CAF correlated positively with serum creatinine, cystatin C and negatively with eGFR on day 1, day 2 and at 6 months after kidney transplantation. CAF and NGAL fell rapidly into the normal range on the second postoperative day, prior to creatinine and cystatin C. CONCLUSIONS This study verified the reference intervals for serum CAF. CAF could be a potential new biomarker for kidney function monitoring.
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Affiliation(s)
- Dan Yu
- Department of Clinical Laboratory, Peking University First Hospital, Beijing, China
| | - Hai-Xia Li
- Department of Clinical Laboratory, Peking University First Hospital, Beijing, China
| | - Yi Liu
- Department of Clinical Laboratory, Peking University First Hospital, Beijing, China
| | - Ze-Wei Ying
- Department of Urology, Peking University First Hospital, Beijing, China
| | - Jing-Jing Guo
- Department of Clinical Laboratory, Peking University First Hospital, Beijing, China
| | - Chen-Ying Cao
- Department of Clinical Laboratory, Peking University First Hospital, Beijing, China
| | - Jia Wang
- Department of Clinical Laboratory, Peking University First Hospital, Beijing, China
| | - Yuan-Fang Li
- Department of Clinical Laboratory, Peking University First Hospital, Beijing, China
| | - Hui-Rong Yang
- Department of Clinical Laboratory, Peking University First Hospital, Beijing, China
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Daryadel A, Haubitz M, Figueiredo M, Steubl D, Roos M, Mäder A, Hettwer S, Wagner CA. The C-Terminal Fragment of Agrin (CAF), a Novel Marker of Renal Function, Is Filtered by the Kidney and Reabsorbed by the Proximal Tubule. PLoS One 2016; 11:e0157905. [PMID: 27380275 PMCID: PMC4933355 DOI: 10.1371/journal.pone.0157905] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 06/07/2016] [Indexed: 02/07/2023] Open
Abstract
Agrin, a multidomain proteoglycan and neurotrypsin, a neuronal serine protease, are important for forming (neuromuscular) synapses. Proteolytical activity of neurotrypsin produces a C-terminal fragment of agrin, termed CAF, of approximately 22 kDA molecular size which also circulates in blood. The presence of CAF in urine suggests either glomerular filtration or secretion into urine. Blood levels of CAF have been identified as a potential novel marker of kidney function. Here we describe that several nephron segments in the mouse kidney express agrin and neutrotrypsin in addition to the localization of both protein in the glomerulum. Agrin mRNA and protein was detected in almost all nephron segments and mRNA abundance was highest in the inner medullary collecting duct. Neurotrypsin mRNA was mostly detected in the thick ascending limb of the loop of Henle, the distal convoluted tubule, and the inner medullary collecting duct. Moreover, we show that the proximal tubule absorbs injected recombinant CAF by a process shared with receptor-mediated and fluid phase endocytosis. Co-injection of CAF with recombinant human transferrin, a substrate of the receptor-mediated endocytic pathway as well as with FITC-labelled dextran (10 kDa), a marker of fluid phase endocytosis, showed partial colocalization of CAF with both markers. Further colocalization of CAF with the lysosomal marker cathepsin B suggested degradation of CAF by the lysosome in the proximal tubule. Thus, the murine kidney expresses agrin and neurotrypsin in nephron segments beyond the glomerulum. CAF is filtered by the glomerulum and is reabsorbed by endocytosis by the proximal tubule. Thus, impaired kidney function could impair glomerular clearance of CAF and thereby increase circulating CAF levels.
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Affiliation(s)
- Arezoo Daryadel
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | | | - Marta Figueiredo
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Dominik Steubl
- Department of Nephrology, Klinikum rechts der Isar, Munich, Germany
| | - Marcel Roos
- Department of Nephrology, Klinikum rechts der Isar, Munich, Germany
| | | | | | - Carsten A. Wagner
- Institute of Physiology and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- * E-mail:
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Scherbakov N, Knops M, Ebner N, Valentova M, Sandek A, Grittner U, Dahinden P, Hettwer S, Schefold JC, von Haehling S, Anker SD, Joebges M, Doehner W. Evaluation of C-terminal Agrin Fragment as a marker of muscle wasting in patients after acute stroke during early rehabilitation. J Cachexia Sarcopenia Muscle 2016; 7:60-7. [PMID: 27066319 PMCID: PMC4799857 DOI: 10.1002/jcsm.12068] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 07/15/2015] [Accepted: 07/31/2015] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND C-terminal Agrin Fragment (CAF) has been proposed as a novel biomarker for sarcopenia originating from the degeneration of the neuromuscular junctions. In patients with stroke muscle wasting is a common observation that predicts functional outcome. We aimed to evaluate agrin sub-fragment CAF22 as a marker of decreased muscle mass and physical performance in the early phase after acute stroke. METHODS Patients with acute ischaemic or haemorrhagic stroke (n = 123, mean age 70 ± 11 y, body mass index BMI 27.0 ± 4.9 kg/m(2)) admitted to inpatient rehabilitation were studied in comparison to 26 healthy controls of similar age and BMI. Functional assessments were performed at begin (23 ± 17 days post stroke) and at the end of the structured rehabilitation programme (49 ± 18 days post stroke) that included physical assessment, maximum hand grip strength, Rivermead motor assessment, and Barthel index. Body composition was assessed by bioelectrical impedance analysis (BIA). Serum levels of CAF22 were measured by ELISA. RESULTS CAF22 levels were elevated in stroke patients at admission (134.3 ± 52.3 pM) and showed incomplete recovery until discharge (118.2 ± 42.7 pM) compared to healthy controls (95.7 ± 31.8 pM, p < 0.001). Simple regression analyses revealed an association between CAF22 levels and parameters of physical performance, hand grip strength, and phase angle, a BIA derived measure of the muscle cellular integrity. Improvement of the handgrip strength of the paretic arm during rehabilitation was independently related to the recovery of CAF22 serum levels only in those patients who showed increased lean mass during the rehabilitation. CONCLUSIONS CAF22 serum profiles showed a dynamic elevation and recovery in the subacute phase after acute stroke. Further studies are needed to explore the potential of CAF22 as a serum marker to monitor the muscle status in patients after stroke.
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Affiliation(s)
- Nadja Scherbakov
- Center for Stroke Research CSB Charite Universitätsmedizin Berlin Germany; German Centre for Cardiovascular Research (DZHK), partner site Berlin Germany
| | - Michael Knops
- Center for Stroke Research CSB Charite Universitätsmedizin Berlin Germany
| | - Nicole Ebner
- Innovative Clinical Trials, Department of Cardiology and Pneumology University Medicine Göttingen Germany
| | - Miroslava Valentova
- Innovative Clinical Trials, Department of Cardiology and Pneumology University Medicine Göttingen Germany; 1st Department of Internal Medicine Comenius University Bratislava Slovak Republic
| | - Anja Sandek
- Innovative Clinical Trials, Department of Cardiology and Pneumology University Medicine Göttingen Germany
| | - Ulrike Grittner
- Center for Stroke Research CSB Charite Universitätsmedizin Berlin Germany
| | | | | | - Jörg C Schefold
- Department of Intensive Care Medicine Inselspital, University Hospital of Bern Switzerland
| | - Stephan von Haehling
- Innovative Clinical Trials, Department of Cardiology and Pneumology University Medicine Göttingen Germany
| | - Stefan D Anker
- Innovative Clinical Trials, Department of Cardiology and Pneumology University Medicine Göttingen Germany
| | | | - Wolfram Doehner
- Center for Stroke Research CSB Charite Universitätsmedizin Berlin Germany; German Centre for Cardiovascular Research (DZHK), partner site Berlin Germany; Department of Cardiology Charite Universitätsmedizin Berlin Germany
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C-terminal agrin fragment (CAF) as a serum biomarker for residual renal function in peritoneal dialysis patients. Int Urol Nephrol 2014; 47:391-6. [PMID: 25352149 DOI: 10.1007/s11255-014-0852-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 09/22/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND C-terminal agrin fragment (CAF, size 22 kDa) is a promising new biomarker for kidney function. This study evaluated the usefulness of CAF as a serum biomarker for residual renal function (RRF) in patients undergoing automated peritoneal dialysis (APD). PATIENTS AND METHODS Serum, urine and dialysate samples were obtained in 12 end-stage renal disease patients undergoing APD. Total, renal and peritoneal clearances were calculated for CAF, creatinine, blood urea nitrogen (BUN) and cystatin c. kt/V was computed, and RRF (in ml/min) was calculated as the arithmetic mean of creatinine and BUN clearance. Correlations between the biomarkers' serum concentrations, clearances, kt/V and RRF were computed. RESULTS Serum CAF concentrations were highly correlated with serum concentrations of creatinine (r = 0.806, p = 0.002), BUN (r = 0.727, p = 0.007), cystatin c (r = 0.839, p = 0.001) and inversely to 24-h urinary output (r = -0.669, p = 0.017). RRF was inversely correlated with serum concentrations of CAF, cystatin c and creatinine being highest for CAF (r = -0.734, p = 0.007) followed by cystatin c (r = -0.65, p = 0.022) and creatinine (r = -0.606, p = 0.037). Serum BUN was not significantly associated with RRF (r = -0.497, p = 0.101). Age, weight and gender did not significantly affect serum CAF concentrations. CONCLUSION Serum CAF provides a robust serum biomarker for RRF in peritoneal dialysis patients undergoing APD, possibly outperforming the value of conventional biomarkers.
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