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Yang W, Zhao T, Chen X, Wang S, Wang Y, Su T. Determinants and impact of calcium oxalate crystal deposition on renal outcomes in acute kidney injury patients. Ren Fail 2024; 46:2334396. [PMID: 38570195 PMCID: PMC10993744 DOI: 10.1080/0886022x.2024.2334396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 03/19/2024] [Indexed: 04/05/2024] Open
Abstract
OBJECTIVES Calcium oxalate (CaOx) crystal deposition in acute kidney injury (AKI) patients is under recognized but impacts renal outcomes. This study investigates its determinants and effects. METHODS We studied 814 AKI patients with native kidney biopsies from 2011 to 2020, identifying CaOx crystal deposition severity (mild: <5, moderate: 5-10, severe: >10 crystals per section). We assessed factors like urinary oxalate, citrate, urate, electrolytes, pH, tubular calcification index, and SLC26A6 expression, comparing them with creatinine-matched AKI controls without oxalosis. We analyzed how these factors relate to CaOx severity and their impact on renal recovery (eGFR < 15 mL/min/1.73 m2 at 3-month follow-up). RESULTS CaOx crystal deposition was found in 3.9% of the AKI cohort (32 cases), with 72% due to nephrotoxic medication-induced tubulointerstitial nephritis. Diuretic use, higher urinary oxalate-to-citrate ratio induced by hypocitraturia, and tubular calcification index were significant contributors to moderate and/or severe CaOx deposition. Poor baseline renal function, low urinary chloride, high uric acid and urea nitrogen, tubular SLC26A6 overexpression, and glomerular sclerosis were also associated with moderate-to-severe CaOx deposition. Kidney recovery was delayed, with 43.8%, 31.2%, and 18.8% of patients having eGFR < 15 mL/min/1.73 m2 at 4, 12, and 24-week post-injury. Poor outcomes were linked to high urinary α1-microglobulin-to-creatinine (α1-MG/C) ratios and active tubular injury scores. Univariate analysis showed a strong link between this ratio and poor renal outcomes, independent of oxalosis severity. CONCLUSIONS In AKI, CaOx deposition is common despite declining GFR. Factors worsening tubular injury, not just oxalate-to-citrate ratios, are key to understanding impaired renal recovery.
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Affiliation(s)
- Weiwei Yang
- Department of medicine, Renal Division, Peking University First Hospital, Peking University, Institute of Nephrology, Renal Pathology Center, Institute of Nephrology, Peking University, Beijing, PR China
- Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing, PR China
| | - Tao Zhao
- Department of medicine, Renal Division, Peking University First Hospital, Peking University, Institute of Nephrology, Renal Pathology Center, Institute of Nephrology, Peking University, Beijing, PR China
- Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing, PR China
| | - Xuejing Chen
- Department of medicine, Renal Division, Peking University First Hospital, Peking University, Institute of Nephrology, Renal Pathology Center, Institute of Nephrology, Peking University, Beijing, PR China
- Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing, PR China
| | - Suxia Wang
- Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing, PR China
- Research Units of Diagnosis and Treatment of Immune-mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, PR China
| | - Yu Wang
- Department of medicine, Renal Division, Peking University First Hospital, Peking University, Institute of Nephrology, Renal Pathology Center, Institute of Nephrology, Peking University, Beijing, PR China
- Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing, PR China
| | - Tao Su
- Department of medicine, Renal Division, Peking University First Hospital, Peking University, Institute of Nephrology, Renal Pathology Center, Institute of Nephrology, Peking University, Beijing, PR China
- Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing, PR China
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Hawkins-van der Cingel G, Walsh SB, Eckardt KU, Knauf F. Oxalate Metabolism: From Kidney Stones to Cardiovascular Disease. Mayo Clin Proc 2024:S0025-6196(24)00090-9. [PMID: 38762815 DOI: 10.1016/j.mayocp.2024.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/24/2024] [Accepted: 02/09/2024] [Indexed: 05/20/2024]
Abstract
Oxalate kidney stones are common and exert a huge burden of morbidity worldwide. However, circulating or excreted concentrations of oxalate are rarely measured. We argue that oxalate and its metabolism are important above and beyond kidney stone formation. There is emerging evidence that increased concentrations of oxalate could be a driver of chronic kidney disease progression. Furthermore, oxalate has been implicated in cardiovascular disease. Thus, the reduction of elevated plasma oxalate concentrations may represent a novel cardioprotective and nephroprotective strategy.
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Affiliation(s)
- Gerlineke Hawkins-van der Cingel
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany; UCL Department of Renal Medicine, University College London, London, United Kingdom.
| | - Stephen B Walsh
- UCL Department of Renal Medicine, University College London, London, United Kingdom
| | - Kai-Uwe Eckardt
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Felix Knauf
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Nasr SH, Valeri AM, Said SM, Sethi S, Nath KA, Lieske JC, Bu L. Clinicopathologic Characteristics, Etiologies, and Outcome of Secondary Oxalate Nephropathy. Mayo Clin Proc 2024; 99:593-606. [PMID: 38310502 PMCID: PMC11017309 DOI: 10.1016/j.mayocp.2023.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/08/2023] [Accepted: 08/10/2023] [Indexed: 02/05/2024]
Abstract
OBJECTIVE To report the clinicopathologic characteristics, prognostic indicators, prognosis, and transplant outcome of secondary oxalate nephropathy (ON). PATIENTS AND METHODS We performed a retrospective analysis of 113 consecutive patients with secondary ON diagnosed at Mayo Clinic in Rochester, Minnesota, between January 1, 2001, and March 1, 2023. RESULTS The incidence of secondary ON among all native biopsies from Mayo Clinic patients over the study period (n=11,617) was 0.97%. ON was attributed to enteric hyperoxaluria in 60% of the 113 patients (68; most commonly Roux-en-Y gastric bypass), excessive ingestion of foods high in oxalate or oxalate precursors in 23% (26) (most commonly vitamin C), and idiopathic in 17% (19). Most patients presented with acute kidney injury (AKI) (particularly in the ingestion group) or AKI on chronic kidney disease, and 53% (60 of 113) were diabetic. Calcium oxalate crystals were accompanied by acute tubular injury, inflammation, and interstitial fibrosis and tubular atrophy. Concurrent pathologic conditions were present in 53% of the patients (60 of 113), most commonly diabetic nephropathy. After a median follow-up of 36 months, 27% of the patients (30 of 112) had kidney recovery, 19% (21 of 112) had persistent kidney dysfunction, 54% (61 of 112) had development of kidney failure, and 29% (32 of 112) died. The mean kidney survival was worse for patients with a concurrent pathologic lesion (30 months vs 96 months for those without a concurrent pathologic lesion; P<.001). Independent predictors of kidney failure were the degree of interstitial fibrosis and tubular atrophy and nadir estimated glomerular filtration rate but not the degree of crystal deposition. After a median follow-up of 58 months in 23 patients who received kidney transplant, 4 had graft loss (due to ON in 3). The 2-, 5-, and 10-year graft survivals were 90% (18 of 20), 79% (11 of 14), and 50% (6 of 12). CONCLUSION ON is a rare cause of AKI or AKI on chronic kidney disease. Most patients have comorbid pathologic conditions, particularly diabetic nephropathy, which worsen the prognosis. Recurrence in the renal allograft and graft loss may occur if hyperoxaluria is not controlled.
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Affiliation(s)
- Samih H Nasr
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.
| | - Anthony M Valeri
- Division of Nephrology, Columbia University College of Physicians and Surgeons, New York, NY
| | - Samar M Said
- Department of Pathology, Olmsted Medical Center, Rochester, MN
| | - Sanjeev Sethi
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
| | - Karl A Nath
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
| | - John C Lieske
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN; Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
| | - Lihong Bu
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN
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Abstract
Oxalate homeostasis is maintained through a delicate balance between endogenous sources, exogenous supply and excretion from the body. Novel studies have shed light on the essential roles of metabolic pathways, the microbiome, epithelial oxalate transporters, and adequate oxalate excretion to maintain oxalate homeostasis. In patients with primary or secondary hyperoxaluria, nephrolithiasis, acute or chronic oxalate nephropathy, or chronic kidney disease irrespective of aetiology, one or more of these elements are disrupted. The consequent impairment in oxalate homeostasis can trigger localized and systemic inflammation, progressive kidney disease and cardiovascular complications, including sudden cardiac death. Although kidney replacement therapy is the standard method for controlling elevated plasma oxalate concentrations in patients with kidney failure requiring dialysis, more research is needed to define effective elimination strategies at earlier stages of kidney disease. Beyond well-known interventions (such as dietary modifications), novel therapeutics (such as small interfering RNA gene silencers, recombinant oxalate-degrading enzymes and oxalate-degrading bacterial strains) hold promise to improve the outlook of patients with oxalate-related diseases. In addition, experimental evidence suggests that anti-inflammatory medications might represent another approach to mitigating or resolving oxalate-induced conditions.
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Affiliation(s)
- Theresa Ermer
- Department of Surgery, Division of Thoracic Surgery, Yale School of Medicine, New Haven, CT, USA
| | - Lama Nazzal
- Department of Medicine, NYU Grossman School of Medicine, New York, NY, USA
| | - Maria Clarissa Tio
- Division of Nephrology, University of Mississippi Medical Center, Jackson, MS, USA
| | - Sushrut Waikar
- Department of Medicine, Section of Nephrology, Boston University, Boston, MA, USA
| | - Peter S Aronson
- Department of Internal Medicine, Section of Nephrology, Yale School of Medicine, New Haven, CT, USA
| | - Felix Knauf
- Department of Internal Medicine, Section of Nephrology, Yale School of Medicine, New Haven, CT, USA. .,Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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