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Kwenda EP, Hernandez AD, Di Valerio E, Canales BK. Renal papillary tip biopsy in stone formers: a review of clinical safety and insights. Urolithiasis 2024; 52:93. [PMID: 38888601 DOI: 10.1007/s00240-024-01596-x] [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: 05/07/2024] [Accepted: 06/10/2024] [Indexed: 06/20/2024]
Abstract
Alexander Randall first published renal papillary tip findings from stone formers in 1937, paving the way for endoscopic assessment to study stone pathogenesis. We performed a literature search to evaluate the safety of papillary tip biopsy and clinical insights gained from modern renal papillary investigations. A search on the topic of renal papillary biopsy provided an overview of Randall's plaques (RP), classification systems for renal papillary grading, and a summary of procedure type, complications, and outcomes. Within 26 identified manuscripts, 660 individuals underwent papillary tip biopsy percutaneously (n = 562), endoscopically (n = 37), or unspecified (n = 23). Post-operative hemoglobin changes were similar to controls. One individual (0.2%) reported fever > 38°, and long-term mean serum creatinine post-biopsy (n = 32) was unchanged. Biopsies during ureteroscopy or PCNL added ~20-30 min of procedure time. Compared to controls, papillary plaque-containing tissue had upregulation in pro-inflammatory genes, immune cells, and cellular apoptosis. Urinary calcium and papillary plaque coverage were found to differ between RP and non-RP stone formers, suggesting differing underlying pathophysiology for these groups. Two renal papillary scoring systems have been externally validated and are used to classify stone formers. Overall, this review shows that renal papillary biopsies have a low complication profile with high potential for further research. Systematic adaption of a papillary grading scale, newer tissue analysis techniques, and the development of animal models of Randall's plaque may allow further exploration of plaque pathogenesis and identify targets for prevention therapies in patients with nephrolithiasis.
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Affiliation(s)
- Elizabeth P Kwenda
- Department of Urology, University of Florida, 1600 SW Archer Road, P.O. Box 100247, Gainesville, FL, 32610-0247, USA.
| | | | | | - Benjamin K Canales
- Department of Urology, University of Florida, 1600 SW Archer Road, P.O. Box 100247, Gainesville, FL, 32610-0247, USA
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Noonin C, Thongboonkerd V. Beneficial roles of gastrointestinal and urinary microbiomes in kidney stone prevention via their oxalate-degrading ability and beyond. Microbiol Res 2024; 282:127663. [PMID: 38422861 DOI: 10.1016/j.micres.2024.127663] [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: 11/17/2023] [Revised: 02/11/2024] [Accepted: 02/19/2024] [Indexed: 03/02/2024]
Abstract
Formation of calcium oxalate (CaOx) crystal, the most common composition in kidney stones, occurs following supersaturation of calcium and oxalate ions in the urine. In addition to endogenous source, another main source of calcium and oxalate ions is dietary intake. In the intestinal lumen, calcium can bind with oxalate to form precipitates to be eliminated with feces. High intake of oxalate-rich foods, inappropriate amount of daily calcium intake, defective intestinal transporters for oxalate secretion and absorption, and gastrointestinal (GI) malabsorption (i.e., from gastric bypass surgery) can enhance intestinal oxalate absorption, thereby increasing urinary oxalate level and risk of kidney stone disease (KSD). The GI microbiome rich with oxalate-degrading bacteria can reduce intestinal oxalate absorption and urinary oxalate level. In addition to the oxalate-degrading ability, the GI microbiome also affects expression of oxalate transporters and net intestinal oxalate transport, cholesterol level, and short-chain fatty acids (SCFAs) production, leading to lower KSD risk. Recent evidence also shows beneficial effects of urinary microbiome in KSD prevention. This review summarizes the current knowledge on the aforementioned aspects. Potential benefits of the GI and urinary microbiomes as probiotics for KSD prevention are emphasized. Finally, challenges and future perspectives of probiotic treatment in KSD are discussed.
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Affiliation(s)
- Chadanat Noonin
- Medical Proteomics Unit, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Visith Thongboonkerd
- Medical Proteomics Unit, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
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Cil O, Chu QT, Lee S, Haggie PM, Verkman AS. Small molecule inhibitor of intestinal anion exchanger SLC26A3 for therapy of hyperoxaluria and nephrolithiasis. JCI Insight 2022; 7:153359. [PMID: 35608921 PMCID: PMC9310519 DOI: 10.1172/jci.insight.153359] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 05/20/2022] [Indexed: 11/17/2022] Open
Abstract
Nephrolithiasis is a common and recurrent disease affecting 9% of the US population. Hyperoxaluria is major risk factor for calcium oxalate kidney stones, which constitute two-thirds of all kidney stones. SLC26A3 (DRA, downregulated in adenoma) is an anion exchanger of chloride, bicarbonate, and oxalate thought to facilitate intestinal oxalate absorption, as evidenced by approximately 70% reduced urine oxalate excretion in knockout mice. We previously identified a small-molecule SLC26A3 inhibitor (DRAinh-A270) that selectively inhibited SLC26A3-mediated chloride/bicarbonate exchange (IC50 ~ 35 nM) and, as found here, oxalate/chloride exchange (IC50 ~ 60 nM). In colonic closed loops in mice, luminal DRAinh-A270 inhibited oxalate absorption by 70%. Following oral sodium oxalate loading in mice, DRAinh-A270 largely prevented the 2.5-fold increase in urine oxalate/creatinine ratio. In a mouse model of oxalate nephropathy produced by a high-oxalate low-calcium diet, vehicle-treated mice developed marked hyperoxaluria with elevated serum creatinine, renal calcium oxalate crystal deposition, and renal injury, which were largely prevented by DRAinh-A270 (10 mg/kg twice daily). DRAinh-A270 administered over 7 days to healthy mice did not show significant toxicity. Our findings support a major role of SLC26A3 in intestinal oxalate absorption and suggest the therapeutic utility of SLC26A3 inhibition for treatment of hyperoxaluria and prevention of calcium oxalate nephrolithiasis.
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Affiliation(s)
- Onur Cil
- Department of Medicine and Physiology, University of California, San Francisco, San Francisco, United States of America
| | - Qi Tifany Chu
- Department of Pediatrics, University of California, San Francisco, San Francisco, United States of America
| | - Sujin Lee
- Department of Medicine and Physiology, University of California, San Francisco, San Francisco, United States of America
| | - Peter M Haggie
- Department of Medicine and Physiology, University of California, San Francisco, San Francisco, United States of America
| | - Alan S Verkman
- Department of Medicine and Physiology, University of California, San Francisco, San Francisco, United States of America
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Whittamore JM, Hatch M. Oxalate Flux Across the Intestine: Contributions from Membrane Transporters. Compr Physiol 2021; 12:2835-2875. [PMID: 34964122 DOI: 10.1002/cphy.c210013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epithelial oxalate transport is fundamental to the role occupied by the gastrointestinal (GI) tract in oxalate homeostasis. The absorption of dietary oxalate, together with its secretion into the intestine, and degradation by the gut microbiota, can all influence the excretion of this nonfunctional terminal metabolite in the urine. Knowledge of the transport mechanisms is relevant to understanding the pathophysiology of hyperoxaluria, a risk factor in kidney stone formation, for which the intestine also offers a potential means of treatment. The following discussion presents an expansive review of intestinal oxalate transport. We begin with an overview of the fate of oxalate, focusing on the sources, rates, and locations of absorption and secretion along the GI tract. We then consider the mechanisms and pathways of transport across the epithelial barrier, discussing the transcellular, and paracellular components. There is an emphasis on the membrane-bound anion transporters, in particular, those belonging to the large multifunctional Slc26 gene family, many of which are expressed throughout the GI tract, and we summarize what is currently known about their participation in oxalate transport. In the final section, we examine the physiological stimuli proposed to be involved in regulating some of these pathways, encompassing intestinal adaptations in response to chronic kidney disease, metabolic acid-base disorders, obesity, and following gastric bypass surgery. There is also an update on research into the probiotic, Oxalobacter formigenes, and the basis of its unique interaction with the gut epithelium. © 2021 American Physiological Society. Compr Physiol 11:1-41, 2021.
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Affiliation(s)
- Jonathan M Whittamore
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Marguerite Hatch
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, Florida, USA
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Ormanji MS, Rodrigues FG, Heilberg IP. Dietary Recommendations for Bariatric Patients to Prevent Kidney Stone Formation. Nutrients 2020; 12:nu12051442. [PMID: 32429374 PMCID: PMC7284744 DOI: 10.3390/nu12051442] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/09/2020] [Accepted: 05/13/2020] [Indexed: 12/12/2022] Open
Abstract
Bariatric surgery (BS) is one of the most common and efficient surgical procedures for sustained weight loss but is associated with long-term complications such as nutritional deficiencies, biliary lithiasis, disturbances in bone and mineral metabolism and an increased risk of nephrolithiasis, attributed to urinary metabolic changes resultant from low urinary volume, hypocitraturia and hyperoxaluria. The underlying mechanisms responsible for hyperoxaluria, the most common among all metabolic disturbances, may comprise increased intestinal oxalate absorption consequent to decreased calcium intake or increased dietary oxalate, changes in the gut microbiota, fat malabsorption and altered intestinal oxalate transport. In the current review, the authors present a mechanistic overview of changes found after BS and propose dietary recommendations to prevent the risk of urinary stone formation, focusing on the role of dietary oxalate, calcium, citrate, potassium, protein, fat, sodium, probiotics, vitamins D, C, B6 and the consumption of fluids.
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Affiliation(s)
- Milene S. Ormanji
- Nephrology Division, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil; (M.S.O.); (F.G.R.)
| | - Fernanda G. Rodrigues
- Nephrology Division, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil; (M.S.O.); (F.G.R.)
- Department of Nutrition, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
| | - Ita P. Heilberg
- Nephrology Division, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil; (M.S.O.); (F.G.R.)
- Department of Nutrition, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
- Correspondence: ; Tel.: +55-(11)-5576-4848 (ext. 2465)
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Abstract
BACKGROUND Bariatric surgery is associated with hyperoxaluria hence predisposing to nephrolithiasis. The present study aimed to investigate the underlying mechanisms contributing to increased urinary oxalate in a mini-gastric bypass (MGB) surgery model in rats under different dietary conditions. The expression of intestinal oxalate transporters was also evaluated. METHODS Male rats underwent MGB (n = 21) or Sham procedure (n = 21) and after recovery were fed a standard or high-fat diet with or without oxalate for 8 weeks. Stool and urine were collected before surgery (baseline) and at the end of protocol (final), when intestinal fragments were harvested for expression of Slc26a3 and Slc26a6 oxalate transporters. RESULTS MGB groups fed with fat, irrespective of oxalate supplementation, presented steatorrhea. In MGB animals fed with fat and oxalate (Fat + Ox), final values of urinary oxalate and calcium oxalate supersaturation risk were markedly and significantly increased versus baseline or Sham animals under the same diet, as well as MGB groups under other diets. Slc26a3 was decreased in biliopancreatic limbs of MGB rats, probably reflecting a physiological adaptation to the restriction of food passage. Slc26a6 was not altered in any harvested intestinal fragment. CONCLUSIONS A high-fat and oxalate diet induced hyperoxaluria and elevation in calcium oxalate supersaturation risk in a MGB rat model. The presence of fat malabsorption and increased dietary oxalate absorption, but not modifications of Slc26a3 and Slc26a6 oxalate transporters, accounted for these findings, suggesting that bariatric patients may benefit from a low-fat and low-oxalate diet.
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Canales BK, Hatch M. Oxalobacter formigenes colonization normalizes oxalate excretion in a gastric bypass model of hyperoxaluria. Surg Obes Relat Dis 2017; 13:1152-1157. [PMID: 28552742 DOI: 10.1016/j.soard.2017.03.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 03/12/2017] [Accepted: 03/13/2017] [Indexed: 11/25/2022]
Abstract
BACKGROUND Hyperoxaluria and oxalate kidney stones frequently develop after Roux-en-Y gastric bypass (RYGB). Oxalobacter formigenes can degrade ingested oxalate. OBJECTIVES Examine the effect of O. formigenes wild rat strain (OXWR) colonization on urinary oxalate excretion and intestinal oxalate transport in a hyperoxaluric RYGB model. SETTING Basic Science Laboratory, United States. METHODS At 21 weeks of age, 28 obese male Sprague-Dawley rats survived Sham (n = 10) or RYGB (n = 18) surgery and were maintained on a 1.5% potassium oxalate, 40% fat diet. At 12 weeks postoperatively, half the animals in each group were gavaged with OXWR. At 16 weeks, percent dietary fat content was lowered to 10%. Urine and stool were collected weekly to determine oxalate and colonization status, respectively. At week 20, [14 C]-oxalate fluxes and electrical parameters were measured in vitro across isolated distal colon and jejunal (Roux limb) tissue mounted in Ussing Chambers. RESULTS RYGB animals lost 22% total weight while Shams gained 5%. On a moderate oxalate diet, urinary oxalate excretion was 4-fold higher in RYGB than Sham controls. OXWR colonization, obtained in all gavaged animals, reduced urinary oxalate excretion 74% in RYGB and 39% in Sham and was further augmented by lowering the percentage of dietary fat. Finally, OXWR colonization significantly enhanced basal net colonic oxalate secretion in both groups. CONCLUSIONS In our model, OXWR lowered urinary oxalate by luminal oxalate degradation in concert with promotion of enteric oxalate elimination. Trials of O. formigenes colonization and low-fat diet are warranted in calcium oxalate stone formers with gastric bypass and resistant hyperoxaluria.
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Affiliation(s)
- Benjamin K Canales
- Department of Urology, North Florida/South Georgia Veterans Affairs Medical Center and University of Florida, Gainesville, Florida.
| | - Marguerite Hatch
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, Florida
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Abstract
This perspective focuses on how the gut microbiota can impact urinary oxalate excretion in the context of hyperoxaluria, a major risk factor in kidney stone disease. In the genetic disease of Primary Hyperoxaluria Type 1 (PH1), an increased endogenous production of oxalate, due to a deficiency of the liver enzyme alanine-glyoxylate aminotransferase (AGT), results in hyperoxaluria and oxalate kidney stones. The constant elevation in urinary oxalate in PH1 patients ultimately leads to tissue deposition of oxalate, renal failure and death and the only known cure for PH1 is a liver or liver-kidney transplant. The potential impact of a probiotic/therapeutic approach may be clinically significant in PH1 and could also extend to a much larger population of idiopathic oxalate stone formers who comprise ~12% of Americans, individuals with enteric hyperoxaluria, and an emerging population of hyperoxaluric patients who have undergone bariatric surgery and develop kidney stone disease as a consequence.
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Affiliation(s)
- Marguerite Hatch
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida, College of Medicine, Gainesville, FL, USA
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The role of intestinal oxalate transport in hyperoxaluria and the formation of kidney stones in animals and man. Urolithiasis 2016; 45:89-108. [PMID: 27913853 DOI: 10.1007/s00240-016-0952-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 11/22/2016] [Indexed: 12/26/2022]
Abstract
The intestine exerts a considerable influence over urinary oxalate in two ways, through the absorption of dietary oxalate and by serving as an adaptive extra-renal pathway for elimination of this waste metabolite. Knowledge of the mechanisms responsible for oxalate absorption and secretion by the intestine therefore have significant implications for understanding the etiology of hyperoxaluria, as well as offering potential targets for future treatment strategies for calcium oxalate kidney stone disease. In this review, we present the recent developments and advances in this area over the past 10 years, and put to the test some of the new ideas that have emerged during this time, using human and mouse models. A key focus for our discussion are the membrane-bound anion exchangers, belonging to the SLC26 gene family, some of which have been shown to participate in transcellular oxalate absorption and secretion. This has offered the opportunity to not only examine the roles of these specific transporters, revealing their importance to oxalate homeostasis, but to also probe the relative contributions made by the active transcellular and passive paracellular components of oxalate transport across the intestine. We also discuss some of the various physiological stimuli and signaling pathways which have been suggested to participate in the adaptation and regulation of intestinal oxalate transport. Finally, we offer an update on research into Oxalobacter formigenes, alongside recent investigations of other oxalate-degrading gut bacteria, in both laboratory animals and humans.
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