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Pan X, Peng J, Zhu R, An N, Pei J. Non-invasive biomarkers of acute rejection in pediatric kidney transplantation: New targets and strategies. Life Sci 2024; 348:122698. [PMID: 38710278 DOI: 10.1016/j.lfs.2024.122698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 04/17/2024] [Accepted: 05/03/2024] [Indexed: 05/08/2024]
Abstract
Kidney transplantation is the preferred treatment for pediatric end-stage renal disease. However, pediatric recipients face unique challenges due to their prolonged need for kidney function to accommodate growth and development. The continual changes in the immune microenvironment during childhood development and the heightened risk of complications from long-term use of immunosuppressive drugs. The overwhelming majority of children may require more than one kidney transplant in their lifetime. Acute rejection (AR) stands as the primary cause of kidney transplant failure in children. While pathologic biopsy remains the "gold standard" for diagnosing renal rejection, its invasive nature raises concerns regarding potential functional impairment and the psychological impact on children due to repeated procedures. In this review, we outline the current research status of novel biomarkers associated with AR in urine and blood after pediatric kidney transplantation. These biomarkers exhibit superior diagnostic and prognostic performance compared to conventional ones, with the added advantages of being less invasive and highly reproducible for long-term graft monitoring. We also integrate the limitations of these novel biomarkers and propose a refined monitoring model to optimize the management of AR in pediatric kidney transplantation.
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Affiliation(s)
- Xingyu Pan
- Department of Pediatric surgrey, Guizhou Provincial People's Hospital, Guiyang 550002, China
| | - Jinpu Peng
- Department of Pediatric surgrey, Guizhou Provincial People's Hospital, Guiyang 550002, China
| | - Rong Zhu
- Department of Pediatric surgrey, Guizhou Provincial People's Hospital, Guiyang 550002, China
| | - Nini An
- Department of Pediatric surgrey, Guizhou Provincial People's Hospital, Guiyang 550002, China
| | - Jun Pei
- Department of Pediatric surgrey, Guizhou Provincial People's Hospital, Guiyang 550002, China.
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2
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Yaffe HC, von Ahrens D, Urioste A, Mas VR, Akalin E. Impact of Deceased-donor Acute Kidney Injury on Kidney Transplantation. Transplantation 2024; 108:1283-1295. [PMID: 37990359 DOI: 10.1097/tp.0000000000004848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Even as record numbers of deceased donors are undergoing organ recovery, the global transplant community continues to struggle with a shortage of donor organs and a high organ discard rate. Acute kidney injury (AKI) occurs in many hospitalized patients, including up to 25% of patients in critical condition. Registry studies have shown a significant increase in nonrecovery or organ discard rates in AKI donors, despite most studies reporting similar clinical outcomes compared with non-AKI donors. This review aims to capture the salient information learned from these studies and to summarize the efforts that have been made to gain a more granular understanding of how kidneys from donors with AKI behave posttransplant. In particular, we reviewed the studies that analyzed the clinical outcomes in different stages of AKI and AKI in marginal donors, such as kidney donor profile index of >85%, older donors, and donation after circulatory death donors. We summarized studies investigating molecular biomarkers, transcriptomics, and possible future therapeutic targets for postdonation AKI.
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Affiliation(s)
- Hillary C Yaffe
- Montefiore Einstein Center for Transplantation, Department of Surgery, Montefiore Medical Center, Bronx, NY
- Albert Einstein College of Medicine, Bronx, NY
| | - Dagny von Ahrens
- Montefiore Einstein Center for Transplantation, Department of Surgery, Montefiore Medical Center, Bronx, NY
- Albert Einstein College of Medicine, Bronx, NY
| | - Alejandra Urioste
- Surgical Sciences Division, University of Maryland School of Medicine, Baltimore, MD
| | - Valeria R Mas
- Surgical Sciences Division, University of Maryland School of Medicine, Baltimore, MD
| | - Enver Akalin
- Albert Einstein College of Medicine, Bronx, NY
- Montefiore Einstein Center for Transplantation, Department of Medicine, Montefiore Medical Center, Bronx, NY
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3
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D Souza S, Obeid W, Hernandez J, Hu D, Wen Y, Moledina DG, Albert A, Gregg A, Wheeler A, Philbrook HT, Parikh CR. The development of lateral flow devices for urinary biomarkers to assess kidney health. Sci Rep 2024; 14:8516. [PMID: 38609491 PMCID: PMC11014899 DOI: 10.1038/s41598-024-59104-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 04/08/2024] [Indexed: 04/14/2024] Open
Abstract
Serum creatinine levels are insensitive to real-time changes in kidney function or injury. There is a growing interest in assessing kidney injury by measuring biomarkers in body fluid. From our previous studies, we identified and reported three urinary biomarkers namely Uromodulin (UMOD), Osteopontin (OPN), and Interleukin-9 (IL-9) to be associated with kidney health. The availability of a rapid point-of-care test for these urinary biomarkers will potentially accelerate its applicability and accessibility. In this study, we aimed to develop novel lateral flow device (LFD) for UMOD, OPN and IL-9. We tested paired antibodies using Enzyme Linked Immunosorbent Assay wherein we observed functionality only for UMOD and OPN and not for IL-9. A conjugation buffer pH of 7.8 and 8.5 was found suitable at a detection antibody concentration of 15 µg/mL for LFD development. The developed LFDs were found to quantitatively measure UMOD standard (LLOD of 80,000 pg/mL) and OPN standard (LLOD of 8600 pg/mL) respectively. The LFD was also able to measure human urinary UMOD and OPN with a percent CV of 12.12 and 5.23 respectively.
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Affiliation(s)
- Serena D Souza
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, 1830 E. Monument St., Suite 416, Baltimore, MD, 21287, USA
| | - Wassim Obeid
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, 1830 E. Monument St., Suite 416, Baltimore, MD, 21287, USA
| | - Jeanine Hernandez
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, 1830 E. Monument St., Suite 416, Baltimore, MD, 21287, USA
| | - David Hu
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, 1830 E. Monument St., Suite 416, Baltimore, MD, 21287, USA
| | - Yumeng Wen
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, 1830 E. Monument St., Suite 416, Baltimore, MD, 21287, USA
| | - Dennis G Moledina
- Section of Nephrology and Clinical and Translational Research Accelerator, Department of Internal Medicine, School of Medicine, Yale University, New Haven, CT, USA
| | - Andre Albert
- Mologic Inc (D/B/A Global Access Diagnostics), 83 Pineland Drive, Gray Hall Suite 202, New Gloucester, ME, USA
| | - Anya Gregg
- Mologic Ltd (D/B/A Global Access Diagnostics), Bedford Technology Park, Thurleigh, UK
| | - Andrew Wheeler
- Mologic Inc (D/B/A Global Access Diagnostics), 83 Pineland Drive, Gray Hall Suite 202, New Gloucester, ME, USA
| | - Heather Thiessen Philbrook
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, 1830 E. Monument St., Suite 416, Baltimore, MD, 21287, USA
| | - Chirag R Parikh
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, 1830 E. Monument St., Suite 416, Baltimore, MD, 21287, USA.
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4
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Parikh CR, Coca SG. Are biomarkers in acute kidney injury ready for prime time? The time is right for a second look. Kidney Int 2024; 105:675-678. [PMID: 38519236 DOI: 10.1016/j.kint.2024.01.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/18/2023] [Accepted: 01/03/2024] [Indexed: 03/24/2024]
Affiliation(s)
- Chirag R Parikh
- Division of Nephrology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
| | - Steven G Coca
- Barbara T. Murphy Division of Nephrology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
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Thielemans R, Speeckaert R, Delrue C, De Bruyne S, Oyaert M, Speeckaert MM. Unveiling the Hidden Power of Uromodulin: A Promising Potential Biomarker for Kidney Diseases. Diagnostics (Basel) 2023; 13:3077. [PMID: 37835820 PMCID: PMC10572911 DOI: 10.3390/diagnostics13193077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/25/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Uromodulin, also known as Tamm-Horsfall protein, represents the predominant urinary protein in healthy individuals. Over the years, studies have revealed compelling associations between urinary and serum concentrations of uromodulin and various parameters, encompassing kidney function, graft survival, cardiovascular disease, glucose metabolism, and overall mortality. Consequently, there has been a growing interest in uromodulin as a novel and effective biomarker with potential applications in diverse clinical settings. Reduced urinary uromodulin levels have been linked to an elevated risk of acute kidney injury (AKI) following cardiac surgery. In the context of chronic kidney disease (CKD) of different etiologies, urinary uromodulin levels tend to decrease significantly and are strongly correlated with variations in estimated glomerular filtration rate. The presence of uromodulin in the serum, attributable to basolateral epithelial cell leakage in the thick ascending limb, has been observed. This serum uromodulin level is closely associated with kidney function and histological severity, suggesting its potential as a biomarker capable of reflecting disease severity across a spectrum of kidney disorders. The UMOD gene has emerged as a prominent locus linked to kidney function parameters and CKD risk within the general population. Extensive research in multiple disciplines has underscored the biological significance of the top UMOD gene variants, which have also been associated with hypertension and kidney stones, thus highlighting the diverse and significant impact of uromodulin on kidney-related conditions. UMOD gene mutations are implicated in uromodulin-associated kidney disease, while polymorphisms in the UMOD gene show a significant association with CKD. In conclusion, uromodulin holds great promise as an informative biomarker, providing valuable insights into kidney function and disease progression in various clinical scenarios. The identification of UMOD gene variants further strengthens its relevance as a potential target for better understanding kidney-related pathologies and devising novel therapeutic strategies. Future investigations into the roles of uromodulin and regulatory mechanisms are likely to yield even more profound implications for kidney disease diagnosis, risk assessment, and management.
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Affiliation(s)
- Raïsa Thielemans
- Department of Nephrology, Ghent University Hospital, 9000 Ghent, Belgium; (R.T.); (C.D.)
| | | | - Charlotte Delrue
- Department of Nephrology, Ghent University Hospital, 9000 Ghent, Belgium; (R.T.); (C.D.)
| | - Sander De Bruyne
- Department of Laboratory Medicine, Ghent University Hospital, 9000 Ghent, Belgium; (S.D.B.); (M.O.)
| | - Matthijs Oyaert
- Department of Laboratory Medicine, Ghent University Hospital, 9000 Ghent, Belgium; (S.D.B.); (M.O.)
| | - Marijn M. Speeckaert
- Department of Nephrology, Ghent University Hospital, 9000 Ghent, Belgium; (R.T.); (C.D.)
- Research Foundation Flanders, 1000 Brussels, Belgium
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6
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LaFavers KA, Gaddy AR, Micanovic R, Lingeman J, Williams JC, Coe FL, El-Achkar TM, Worcester E. Water Loading and Uromodulin Secretion in Healthy Individuals and Idiopathic Calcium Stone Formers. Clin J Am Soc Nephrol 2023; 18:1059-1067. [PMID: 37256909 PMCID: PMC10564375 DOI: 10.2215/cjn.0000000000000202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 05/24/2023] [Indexed: 06/02/2023]
Abstract
BACKGROUND Uromodulin is a protein made only by the kidney and released in urine, circulating in polymerizing and nonpolymerizing forms. This protein's multiple functions include inhibition of stone formation in the urine. The physiological determinants of uromodulin production are incompletely understood. METHODS We investigated changes in uromodulin levels and key factors governing its production and release in urine and serum. We performed an experiment to determine whether water loading, a common intervention to prevent stone formation, will alter the rate of uromodulin production. During a 2-day period, 17 stone forming participants and 14 control participants were subjected to water loading (day 1) and normal fluid intake (day 2). Uromodulin levels were measured on timed hourly collections in urine and plasma during the period of the study. RESULTS Water loading increased urinary uromodulin secretion (33±4 versus 10±4 μ g/min at baseline, P < 0.0001) in stone formers and control participants. Despite high urine volumes, most participants maintained relatively stable urinary uromodulin concentrations. Native Western blots for polymerizing and nonpolymerizing uromodulin suggest that polymerizing uromodulin was the predominant form at higher urinary flow volumes. Urine flow rates and sodium excretion were significant correlates of urinary uromodulin production. Water loading did not affect serum uromodulin levels, which were also not associated with urinary uromodulin. CONCLUSIONS Water loading increases the secretion of polymerizing urinary uromodulin. This increased secretion reduces the variability of urinary uromodulin concentrations despite high urine volumes. Serum uromodulin levels were not affected by this treatment.
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Affiliation(s)
- Kaice A. LaFavers
- Division of Nephrology and Hypertension, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Anna R. Gaddy
- Division of Nephrology, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Radmila Micanovic
- Division of Nephrology and Hypertension, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - James Lingeman
- Department of Urology, Indiana University School of Medicine, Indianapolis, Indiana
| | - James C. Williams
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Fredric L. Coe
- Section of Nephrology, Department of Medicine, The University of Chicago Medicine, Chicago, Illinois
| | - Tarek M. El-Achkar
- Division of Nephrology and Hypertension, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, Indiana
- Roudebush VA Medical Center, Indianapolis, Indiana
| | - Elaine Worcester
- Section of Nephrology, Department of Medicine, The University of Chicago Medicine, Chicago, Illinois
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LaFavers K, Garimella PS. Uromodulin: more than a marker for chronic kidney disease progression. Curr Opin Nephrol Hypertens 2023; 32:271-277. [PMID: 36912260 DOI: 10.1097/mnh.0000000000000885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
PURPOSE OF REVIEW Uromodulin, a protein that is highly conserved across several species through evolution, functions to maintain homeostasis and prevent disease development and progression. Historically, the role of uromodulin has been thought to be limited to the kidney and genitourinary tract. This review highlights developments indicating a broader role of uromodulin in human health. RECENT FINDINGS Although initially discovered in the urine and found to have immunomodulatory properties, recent findings indicate that serum uromodulin (sUMOD) is distinct from urine uromodulin (uUMOD) in its structure, function, and regulation. uUMOD binds pathogenic bacteria in the urine preventing infection and is also upregulated in kidneys undergoing repair after injury. Uromodulin knockout mice exhibit higher mortality in the setting of sepsis which is also associated with upregulation of sUMOD. sUMOD lowers calcification risk but this may be influenced by presence of kidney disease. SUMMARY Uromodulin is an evolutionarily conserved protein produced exclusively in the kidney tubule cells with evolving roles being reported both in the kidney and systemically. Further research should be focused at harnessing its use as a potential therapeutic.
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Affiliation(s)
- Kaice LaFavers
- Division of Nephrology and Hypertension, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Pranav S Garimella
- Division of Nephrology and Hypertension, University of California San Diego, San Diego, California, USA
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Liu C, Alasfar S, Reese PP, Mohan S, Doshi MD, Hall IE, Thiessen Philbrook H, Jia Y, Stewart D, Parikh CR. Trends in the procurement and discard of kidneys from deceased donors with acute kidney injury. Am J Transplant 2022; 22:898-908. [PMID: 34897982 DOI: 10.1111/ajt.16920] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 11/11/2021] [Accepted: 12/02/2021] [Indexed: 01/25/2023]
Abstract
Kidney allocation trends from deceased donors with acute kidney injury (AKI) have not been characterized since initial Kidney Donor Profile Index reporting in 2012 and its use under the revised Kidney Allocation System (KAS) in 2014. We conducted a retrospective analysis of US registry data to characterize kidney procurement and discard trends in deceased donors with AKI, defined by ≥50% or ≥0.3 mg/dl (≥4.0 mg/dl or ≥200% for stage 3) increase in terminal serum creatinine from admission. From 2010 to 2020, 172 410 kidneys were procured from 93 341 deceased donors 16 years or older; 34 984 kidneys were discarded (17 559 from AKI donors). The proportion of stage 3 AKI donors doubled from 6% (412/6841) in 2010 to 12% (1365/11493) in 2020. Procurement of stage 3 AKI kidneys increased from 51% (423/824) to 80% (2183/2730). While discard of stage 3 AKI kidneys increased from 41% (175/423) in 2010 to 44% (960/2183) in 2020, this increase was not statistically significant in interrupted time-series analysis following KAS implementation (slope difference -0.41 [-3.22, 2.4], and level change 3.09 [-6.4, 12.6]). In conclusion, the absolute number of stage 3 AKI kidneys transplanted has increased. Ongoing high discard rates of these kidneys suggest opportunities for improved utilization.
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Affiliation(s)
- Caroline Liu
- Icahn School of Medicine at Mount Sinai, New York, New York
| | - Sami Alasfar
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Peter P Reese
- Department of Biostatistics, Epidemiology and Informatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Renal-Electrolyte and Hypertension Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Sumit Mohan
- Division of Nephrology, Department of Medicine, New York-Presbyterian/Columbia University Irving Medical Center, New York, New York.,Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York
| | - Mona D Doshi
- Department of Medicine, University of Michigan, Ann Arbor, Michigan
| | - Isaac E Hall
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah
| | - Heather Thiessen Philbrook
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yaqi Jia
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Darren Stewart
- Research Department, United Network for Organ Sharing, Richmond, Virginia
| | - Chirag R Parikh
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Mohan S, Parikh CR. Underscoring the Case for Better Markers of Kidney Injury in Deceased Donors. Am J Kidney Dis 2021; 79:156-158. [PMID: 34742616 DOI: 10.1053/j.ajkd.2021.08.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/10/2021] [Indexed: 11/11/2022]
Affiliation(s)
- Sumit Mohan
- Department of Medicine, Division of Nephrology, Columbia University Vagelos College of Physicians & Surgeons, New York, New York; Department of Epidemiology, Columbia University Mailman School of Public Health, New York, New York
| | - Chirag R Parikh
- Division of Nephrology, School of Medicine, Johns Hopkins University, Baltimore, Maryland; Department of Epidemiology, School of Public Health, Johns Hopkins University, Baltimore, Maryland.
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10
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Kaleta B. Osteopontin and Transplantation: Where Are We Now? Arch Immunol Ther Exp (Warsz) 2021; 69:15. [PMID: 34019147 PMCID: PMC8139897 DOI: 10.1007/s00005-021-00617-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 05/12/2021] [Indexed: 11/26/2022]
Abstract
Organ transplantation represents the optimal therapeutic tool for patients with end-stage organ failure. Hematopoietic stem cell transplantation (HSCT) is likewise an effective therapy for a wide range of malignant and non-malignant diseases. Better understanding of transplantation immunology and the use of multi-modal immunosuppression protocols, can decrease the risk of graft failure and graft-versus-host disease (GVHD) after HSCT. Nevertheless, a major challenge of modern transplantology still seems to be finding non-invasive biomarkers for recipients selection, monitoring of allograft function, and diagnosis of rejection. Since proinflammatory cytokine osteopontin (OPN) is closely involved in regulating both adaptive and innate immune responses, as well as the pathogenesis of inflammatory and autoimmune diseases, it is likely to play an important role in organ and HSC transplantation. This review is to summarize recent advances in our knowledge about OPN function in the kidney, heart, liver, lung, and HSC transplantation. Most studies found that elevated OPN is associated with poorer graft function in kidney, heart, liver and lung recipients. Moreover, some reports suggested that this protein can play role in GVHD pathogenesis. However, due to relatively small number of similar studies, as well as some inconclusive results, future investigation in this field is needed to verify if OPN can serve as a biomarker of organ and HSC transplantation. The knowledge about such markers will promote our understanding of the mechanisms underlying graft dysfunction and posttransplant mortality. In addition, such knowledge may be helpful in the development of new treatment strategies and identification of recipients with increased risk of allograft failure.
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Affiliation(s)
- Beata Kaleta
- Department of Clinical Immunology, Medical University of Warsaw, Nowogrodzka 59 St., 02-006, Warsaw, Poland.
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Abstract
Despite advancements in standardizing the criteria for acute kidney injury (AKI), its definition remains based on changes in serum creatinine and urinary output that do not specifically represent tubular function or injury and that have significant limitations in the acute hospital setting. Much effort in nephrology has centered on identifying biomarkers of AKI to address these limitations. This review summarizes recent advances in our knowledge of biomarkers involved in pathophysiological processes during AKI and describes their potential clinical implications. Blood and urine biomarkers are released via various mechanisms during renal tubular injury. Urinary kidney injury molecule-1 (KIM-1), liver-type fatty acid binding protein (L-FABP), insulin-like growth factor-binding protein-7 (IGFBP-7), and tissue inhibitor of metalloprotease-2 (TIMP-2) are released from the proximal tubule while uromodulin (UMOD) is secreted from the loop of Henle and neutrophil gelatinase-associated lipocalin (NGAL) is released from the distal tubule. These biomarkers could therefore be used to localize specific segments of injured tubules. Biomarkers also have diverse roles in pathophysiological processes in AKI, including inflammation, repair, and fibrosis. Current evidence suggests that these biomarkers could be used to predict the transition to chronic kidney disease (CKD), decrease discard of AKI kidneys, differentiate between kidney dysfunction and injury, guide AKI management, and improve diagnosis of diseases such as acute interstitial nephritis (AIN). They could differentiate between disease phenotypes, facilitate the inclusion of a homogenous patient population in future trials of AKI, and shed light on therapeutic pathways to prevent the transition from AKI to CKD. However, a major limitation of current biomarker research in AKI is the lack of tissue correlation. The Kidney Precision Medicine Project, a large-scale national effort, is currently underway to construct a kidney tissue atlas and expand the use of biomarkers to assess nephron health. Numerous biomarkers are involved in distinct pathophysiological processes after kidney injury and have demonstrated potential to improve diagnosis and risk stratification as well as provide a prognosis for patients with AKI. Some biomarkers are ready for use in clinical trials of AKI and could guide management in various clinical settings. Further investigation of these biomarkers will provide insight that can be applied to develop novel therapeutic agents for AKI.
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Affiliation(s)
- Yumeng Wen
- Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chirag R Parikh
- Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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