oxalates and Renal-Insufficiency

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.

Topics: Homeostasis; Humans; Hyperoxaluria; Kidney; Oxalates; Renal Dialysis; Renal Insufficiency; Renal Insufficiency, Chronic

Secondary hyperoxaluria is associated with poor kidney allograft outcomes after the kidney transplant. Calcium oxalate (CaOx) deposition is common in early allograft biopsies leading to acute tubular necrosis and poor kidney allograft function. Though treatment options for secondary hyperoxaluria are limited, it is crucial to identify patients at increased risk of oxalate nephropathy after the transplant.. Recent data suggest that significant changes in renal replacement therapies and dietary modifications in high-risk patients can prevent kidney allograft damage from the calcium oxalate deposition leading to improve allograft outcomes.. The accurate and timely diagnosis of secondary oxalate nephropathy in kidney transplant recipients is paramount to preserving graft function in the long-term. This review will discuss the incidence, risk factors, prevention, and management of oxalate nephropathy in the kidney allograft.

Topics: Calcium Oxalate; Humans; Hyperoxaluria; Kidney; Kidney Transplantation; Oxalates; Renal Insufficiency

Primary hyperoxaluria (PH) is an inherited disorder that results from the overproduction of endogenous oxalate, leading to recurrent kidney stones, nephrocalcinosis and eventually kidney failure; the subsequent storage of oxalate can cause life-threatening systemic disease. Diagnosis of PH is often delayed or missed owing to its rarity, variable clinical expression and other diagnostic challenges. Management of patients with PH and kidney failure is also extremely challenging. However, in the past few years, several new developments, including new outcome data from patients with infantile oxalosis, from transplanted patients with type 1 PH (PH1) and from patients with the rarer PH types 2 and 3, have emerged. In addition, two promising therapies based on RNA interference have been introduced. These developments warrant an update of existing guidelines on PH, based on new evidence and on a broad consensus. In response to this need, a consensus development core group, comprising (paediatric) nephrologists, (paediatric) urologists, biochemists and geneticists from OxalEurope and the European Rare Kidney Disease Reference Network (ERKNet), formulated and graded statements relating to the management of PH on the basis of existing evidence. Consensus was reached following review of the recommendations by representatives of OxalEurope, ESPN, ERKNet and ERA, resulting in 48 practical statements relating to the diagnosis and management of PH, including consideration of conventional therapy (conservative therapy, dialysis and transplantation), new therapies and recommendations for patient follow-up.

Topics: Child; Consensus; Humans; Hyperoxaluria, Primary; Oxalates; Rare Diseases; Renal Dialysis; Renal Insufficiency

Enteric hyperoxaluria (EH) is a known complication of Roux-en-Y gastric bypass (RYGB) and can lead to nephrolithiasis, oxalate-induced nephropathy, and end-stage renal disease. Recurrent EH-induced renal impairment has been reported after kidney transplantation and may lead to allograft loss. EH occurs in up to one quarter of patients following malabsorption-based bariatric operations. We present a report of medically refractory EH in a renal transplant recipient with allograft dysfunction that was successfully managed with reversal of RYGB. The patient developed renal failure 7 years following gastric bypass requiring renal transplant. Following an uneventful living donor kidney transplant, the patient developed recurrent subacute allograft dysfunction. A diagnosis of oxalate nephropathy was made based on biopsy findings of renal tubular calcium oxalate deposition in conjunction with elevated serum oxalate levels and elevated 24-hr urinary oxalate excretion. Progressive renal failure ensued despite medical management. The patient underwent reversal of her RYGB, which resulted in recovery of allograft function. This report highlights an under-recognized, potentially treatable cause of renal allograft failure in patients with underlying gastrointestinal pathology or history of bariatric surgery and proposes a strategy for management of patients with persistent hyperoxaluria based on a review of the literature.

Topics: Allografts; Calcium Oxalate; Female; Gastric Bypass; Humans; Hyperoxaluria; Kidney Transplantation; Oxalates; Renal Insufficiency

The primary hyperoxalurias (PHs) are inborn errors of glyoxylate metabolism characterized by endogenous oxalate overproduction in the liver, and thus elevated urinary oxalate excretion. The urinary calcium-oxalate (CaOx) supersaturation and the continuous renal accumulation of insoluble CaOx crystals yield a progressive decline in renal function that often ends with renal failure. In PH Type 1 (AGXT mutated), the most frequent and severe condition, patients typically progress to end-stage renal disease (ESRD); in PH Type 2 (GRHPR mutated), 20% of patients develop ESRD, while only one patient with PH Type 3 (HOGA1 mutated) has been reported with ESRD so far. Patients with ESRD undergo frequent maintenance (haemo)dialysis treatment, and finally must receive a combined liver-kidney transplantation as the only curative treatment option available in PH Type 1. In experimental models using oxalate-enriched chow, CaOx crystals were bound to renal tubular cells, promoting a pro-inflammatory environment that led to fibrogenesis in the renal parenchyma by activation of a NACHT, LRR and PYD domains-containing protein 3 (NALP3)-dependent inflammasome in renal dendritic cells and macrophages. Chronic fibrogenesis progressively impaired renal function. Targeting the inflammatory response has recently been suggested as a therapeutic strategy to treat not only oxalate-induced crystalline nephropathies, but also those characterized by accumulation of cystine and urate in other organs. Herein, we summarize the pathogenesis of PH, revising the current knowledge of the CaOx-mediated inflammatory response in animal models of endogenous oxalate overproduction. Furthermore, we highlight the possibility of modifying the NLRP3-dependent inflammasome as a new and complementary therapeutic strategy to treat this severe and devastating kidney disease.

Topics: Adolescent; Adult; Animals; Calcium Oxalate; Child; Child, Preschool; Disease Models, Animal; Humans; Hyperoxaluria, Primary; Infant; Inflammasomes; Kidney; Kidney Failure, Chronic; Kidney Transplantation; Macrophages; Mice; Nephritis; NLR Family, Pyrin Domain-Containing 3 Protein; Oxalates; Renal Dialysis; Renal Insufficiency; RNA Interference; Uric Acid; Young Adult

Although the primary hyperoxalurias (PH) are rare disorders, they are of considerable clinical importance in relation to calcium oxalate urolithiasis and as a cause of renal failure worldwide. Three distinct disorders have been described at the molecular level. The investigation of any child or adult presenting with urinary tract stones or nephrocalcinosis, must exclude PH as an underlying cause. This paper provides a practical approach to the investigation and diagnosis of PH, indicating the importance of distinguishing between the PH types for the purposes of targeting appropriate therapy. Conservative management is explored and the various transplant options are discussed.

Topics: Adult; Child; Diagnosis, Differential; Disease Management; Female; Humans; Hyperoxaluria, Primary; Male; Nephrocalcinosis; Nephrolithiasis; Oxalates; Renal Insufficiency; Urinary Calculi

Even though a certain part of oxalate in the urine derives from metabolized ascorbic acid (AA), the intake of high doses of vitamin C does not increase the risk of calcium oxalate kidney stones due to physiological regulatory factor: gastrointestinal absorption as well as renal tubular reabsorption of AA are saturable processes, and the metabolic transformation of AA to oxalate is limited as well. Older assays for urinary oxalate favored in vitro conversion of AA to oxalate during storage and processing of the samples. Recurrent stone formers and patients with renal failure who have a defect in AA or oxalate metabolism should restrict daily vitamin C intakes to approximately 100 mg. But in the large-scale Harvard Prospective Health Professional Follow-Up Study, those groups in the highest quintile of vitamin C intake (> 1,500 mg/day) had a lower risk of kidney stones than the groups in the lowest quintiles.

Topics: Ascorbic Acid; Calcium Oxalate; Case-Control Studies; Dose-Response Relationship, Drug; Female; Follow-Up Studies; Humans; Intestinal Absorption; Kidney; Kidney Calculi; Male; Oxalates; Renal Insufficiency; Retrospective Studies; Risk Factors

Primary hyperoxaluria type 1 is a rare cause of kidney failure. Stiripentol, an inhibitor of lactate dehydrogenase A, and lumasiran, a small interfering RNA targeting glycolate oxidase, have been proposed as therapeutic options, but clinical data are scarce, especially in adults and transplanted patients. We describe the case of a 51-year-old patient with a biopsy-proven recurrence of oxalate nephropathy after a kidney-only transplantation. He received stiripentol and lumasiran without adverse events. Fourteen months after transplantation, graft function, serum, and urinary oxalate levels have remained stable, and kidney biopsy showed a complete regression of oxalate crystals. Further studies are needed to assess whether this strategy is effective and could replace liver-kidney transplantation.

Topics: Adult; Humans; Hyperoxaluria; Hyperoxaluria, Primary; Kidney Transplantation; Male; Middle Aged; Oxalates; Renal Insufficiency; RNA, Small Interfering

Topics: Humans; Hydroxocobalamin; Hyperoxaluria; Oxalates; Renal Insufficiency; Smoke; Smoke Inhalation Injury

Kidney stones (KSs) are very common, excruciating, and associated with tremendous healthcare cost, chronic kidney disease (CKD), and kidney failure (KF). Most KSs are composed of calcium oxalate and small increases in urinary oxalate concentration significantly enhance the stone risk. Oxalate also potentially contributes to CKD progression, kidney disease-associated cardiovascular diseases, and poor renal allograft survival. This emphasizes the urgent need for plasma and urinary oxalate lowering therapies, which can be achieved by enhancing enteric oxalate secretion. We previously identified

Topics: Animals; Caco-2 Cells; Epithelial Cells; Humans; Hyperoxaluria; Kidney Calculi; Kidney Transplantation; Mice; Oxalates; Oxalobacter formigenes; Peptides; Renal Insufficiency; Renal Insufficiency, Chronic

Topics: Ataxia Telangiectasia; Drug-Related Side Effects and Adverse Reactions; Humans; Oxalates; Renal Insufficiency

Primary hyperoxaluria (PH) is a rare genetic disorder characterized by the excessive production and accumulation of oxalate. We present five cases of PH, each exhibiting varying manifestations of the disorder including a case presenting as postpartum kidney failure. Notably, three of these cases involve a previously unreported mutation.. We evaluated five Indian patients who presented with varying manifestations of PH. The first case, a 30 year old woman, presented as post-partum kidney failure and was found to be having oxalate nephropathy precipitated by dietary oxalate overload in the setting of previously undiagnosed PH. Genetic analysis revealed a previously unreported mutation in the alanine-glyoxylate aminotransferase gene. The patient underwent simultaneous kidney liver transplant. The second and third cases, 26 and 28 year old women respectively, were asymptomatic siblings of the first patient, who were diagnosed through screening. The fourth case is a 12 year boy with PH type 1 presenting as nephrolithiasis and rapidly worsening kidney function requiring combined kidney liver kidney transplant. Case 5 is a 6 year old male child with type 2 PH presenting with nephrolithiasis, nephrocalcinosis and normal kidney function. All the patients were born to consanguineous parents.. Due to limited clinical suspicion and inadequate diagnostic resources in certain countries with limited resources, it is possible for PH to go undiagnosed. The manifestations of the disease can range from no noticeable symptoms to severe disease. Interestingly, in some individuals with primary hyperoxaluria, the disease may not exhibit any symptoms until it is triggered by a high intake of dietary oxalate.

Topics: Adult; Child; Female; Humans; Hyperoxaluria, Primary; Kidney; Kidney Calculi; Male; Oxalates; Renal Insufficiency

Topics: Humans; Hyperoxaluria; Hyperoxaluria, Primary; Male; Oxalates; Oxo-Acid-Lyases; Renal Insufficiency

Primary Hyperoxaluria is a rare autosomal recessive hereditary disorder due to deficient alanine-glyoxylate aminotransferase enzyme with defective glyoxylate metabolism leading to excessive oxalate production and deposition into the tissues (oxalosis). Deposition of excessive calcium oxalates in nephrons leads to crystallization (nephrocalcinosis) which increases risk for end-stage renal disease. We are presenting a case of primary hyperoxaluria type I confirmed with genetic studies.

Topics: Humans; Hyperoxaluria, Primary; Image Processing, Computer-Assisted; Infant; Kidney; Kidney Transplantation; Liver Transplantation; Male; Mutation; Nephrocalcinosis; Oxalates; Prognosis; Renal Dialysis; Renal Insufficiency; Tomography, X-Ray Computed; Transaminases; Ultrasonography

We present a rare case of anaemia secondary to bone marrow infiltration by oxalate crystals and renal failure in a patient diagnosed with primary hyperoxaluria. In our case, the anaemia was recovered after the double liver and kidney transplantation, the latter was performed on two occasions after the failure of the first graft.

Topics: Anemia; Bone Marrow; Humans; Hyperoxaluria; Kidney Transplantation; Liver Transplantation; Male; Middle Aged; Oxalates; Renal Insufficiency

Topics: Aged; Exocrine Pancreatic Insufficiency; Humans; Male; Oxalates; Renal Insufficiency

Primary hyperoxaluria type 1 (PH1) is a rare liver enzymatic defect that causes overproduction of plasma oxalate. Accumulation of oxalate in the kidney and subsequent renal failure are fatal to PH1 patients often in pediatric age. Combined liver and kidney transplantation is the therapy of choice for end-stage renal disease due to PH1. Levels of plasma oxalate remain elevated for several months after liver transplantation, as the residual body oxalate is slowly excreted. Patients with persistent hyperoxaluria after transplant often require hemodialysis, and accumulation of residual oxalate in the kidney can induce graft dysfunction. As the native kidneys are the main target of calcium oxalate accumulation, we postulated that removal of native kidneys could drastically decrease total body oxalate levels after transplantation. Here, we report a case of bilateral nephrectomy at the time of combined liver-kidney transplantation in a pediatric PH1 patient. Bilateral nephrectomy induced a rapid decrease in plasma oxalate to normal levels in less than 20 days, compared to the several months reported in the literature. Our results suggest that removal of native kidneys could be an effective strategy to decrease the need for hemodialysis and the risk of renal dysfunction after combined liver-kidney transplantation in patients with PH1.

Topics: Child; Female; Glomerular Filtration Rate; Humans; Hyperoxaluria; Hyperoxaluria, Primary; Kidney; Kidney Failure, Chronic; Kidney Transplantation; Liver Transplantation; Nephrectomy; Oxalates; Renal Dialysis; Renal Insufficiency

Topics: Humans; Kidney; Male; Middle Aged; Oxalates; Renal Insufficiency; Tea

Topics: Gastrointestinal Microbiome; Humans; Male; Middle Aged; Oxalates; Oxalobacter formigenes; Prunus dulcis; Renal Insufficiency

Oxalate nephrosis is a highly prevalent disease in the Mount Lofty Ranges koala population in South Australia, but associated clinicopathologic findings remain undescribed.. The aims of this study were to determine plasma biochemical and urinalysis variables, particularly for renal function and urinary crystal morphology and composition, in koalas with oxalate nephrosis.. Blood and urine samples from Mount Lofty Ranges koalas with oxalate nephrosis were compared with those unaffected by renal oxalate crystal deposition from Mount Lofty and Kangaroo Island, South Australia and Moggill, Queensland. Plasma and urine biochemistry variables were analyzed using a Cobas Bio analyzer, and urinary oxalate by high-performance liquid chromatography. Urinary crystal composition was determined by infrared spectroscopy and energy dispersive X-ray analysis.. Azotemia (urea > 6.6 mmol/L, creatinine > 150 μmol/L) was found in 93% of koalas with oxalate nephrosis (n = 15). All azotemic animals had renal insufficiency (urine specific gravity [USG] < 1.035), and in 83%, USG was < 1.030. Koalas with oxalate nephrosis were hyperoxaluric compared with Queensland koalas (P < .01). Urinary crystals from koalas with oxalate nephrosis had atypical morphology and were composed of calcium oxalate. Mount Lofty Ranges koalas unaffected by renal oxalate crystal deposition had renal insufficiency (43%), although only 14% had USG < 1.030 (n = 7). Unaffected Mount Lofty Ranges and Kangaroo Island koalas were hyperoxaluric compared with Queensland koalas (P < .01).. Koalas with oxalate nephrosis from the Mount Lofty Ranges had renal insufficiency, hyperoxaluria, and pathognomonic urinary crystals. The findings of this study will aid veterinary diagnosis of this disease.

Topics: Animals; Blood Chemical Analysis; Calcium Oxalate; Female; Hyperoxaluria; Kidney; Male; Microscopy, Electron, Scanning; Nephrosis; Oxalates; Phascolarctidae; Renal Insufficiency; South Australia; Urinalysis

Topics: Biopsy; Creatinine; Cyclosporine; Female; Humans; Hyperoxaluria, Primary; Immunosuppressive Agents; Kidney Transplantation; Middle Aged; Oxalates; Postoperative Complications; Renal Dialysis; Renal Insufficiency; Sirolimus; Transplantation, Homologous; Treatment Outcome

Oxalate nephropathy with renal failure is caused by multiple disorders leading to hyperoxaluria due to either overproduction of oxalate (primary hyperoxaluria) or excessive absorption of dietary oxalate (enteric hyperoxaluria). To study the etiology of renal failure in crystal-induced kidney disease, we created a model of progressive oxalate nephropathy by feeding mice a diet high in soluble oxalate (high oxalate in the absence of dietary calcium). Renal histology was characterized by intratubular calcium-oxalate crystal deposition with an inflammatory response in the surrounding interstitium. Oxalate nephropathy was not found in mice fed a high oxalate diet that also contained calcium. NALP3, also known as cryopyrin, has been implicated in crystal-associated diseases such as gout and silicosis. Mice fed the diet high in soluble oxalate demonstrated increased NALP3 expression in the kidney. Nalp3-null mice were completely protected from the progressive renal failure and death that occurred in wild-type mice fed the diet high in soluble oxalate. NALP3 deficiency did not affect oxalate homeostasis, thereby excluding differences in intestinal oxalate handling to explain the observed phenotype. Thus, progressive renal failure in oxalate nephropathy results primarily from NALP3-mediated inflammation.

Topics: Animals; Carrier Proteins; Disease Models, Animal; Disease Progression; Female; Genotype; Inflammasomes; Inflammation Mediators; Kidney; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nephritis; NLR Family, Pyrin Domain-Containing 3 Protein; Oxalates; Phenotype; Renal Insufficiency; Signal Transduction; Time Factors

The sequence of events by which primary hyperoxaluria type 1 (PH1) causes renal failure is unclear. We hypothesize that proximal tubule (PT) is vulnerable because oxalate secretion raises calcium oxalate (CaOx) supersaturation (SS) there, leading to crystal formation and cellular injury. We studied cortical and papillary biopsies from two PH1 patients with preserved renal function, and seven native kidneys removed from four patients at the time of transplant, after short-term (2) or longer term (2) dialysis. In these patients, and another five PH1 patients without renal failure, we calculated oxalate secretion, and estimated PT CaOx SS. Plasma oxalate was elevated in all PH1 patients and inverse to creatinine clearance. Renal secretion of oxalate was present in all PH1 but rare in controls. PT CaOx SS was >1 in all nonpyridoxine-responsive PH1 before transplant and most marked in patients who developed end stage renal disease (ESRD). PT from PH1 with preserved renal function had birefringent crystals, confirming the presence of CaOx SS, but had no evidence of cortical inflammation or scarring by histopathology or hyaluronan staining. PH1 with short ESRD showed CaOx deposition and hyaluronan staining particularly at the corticomedullary junction in distal PT while cortical collecting ducts were spared. Longer ESRD showed widespread cortical CaOx, and in both groups papillary tissue had marked intratubular CaOx deposits and fibrosis. CaOx SS in PT causes CaOx crystal formation, and CaOx deposition in distal PT appears to be associated with ESRD. Minimizing PT CaOx SS may be important for preserving renal function in PH1.

Topics: Adolescent; Adult; Biopsy; Calcium Oxalate; Child, Preschool; Female; Humans; Hyperoxaluria; Hyperoxaluria, Primary; Infant; Kidney Calculi; Male; Oxalates; Renal Insufficiency

Knauf et al. demonstrate that prolonged activation of the intrarenal inflammasome is responsible for the loss of kidney function in oxalate crystal nephropathy. These findings suggest new therapeutic opportunities for patients suffering from severe hereditary kidney diseases such as primary hyperoxaluria, and reveal a previously unappreciated general mechanism of kidney disease progression that may also contribute to conditions other than crystal nephropathy.

Topics: Animals; Carrier Proteins; Female; Inflammasomes; Inflammation Mediators; Kidney; Male; Nephritis; NLR Family, Pyrin Domain-Containing 3 Protein; Oxalates; Renal Insufficiency

The spectrum of primary hyperoxaluria type I is extremely heterogeneous, ranging from singular to recurrent urolithiasis and early end-stage renal disease (ESRD). In infantile oxalosis, the most devastating form, ESRD occurs as early as within the first weeks of life. No kidney replacement therapy sufficiently removes endogenously overproduced oxalate. However, curative combined liver-kidney transplant often is impracticable in small infants. Oxalobacter formigenes (O formigenes), an anaerobic oxalate-degrading bacterium, is a colonizer of the healthy human colon. Oral administration of O formigenes has been shown to significantly decrease urine and plasma oxalate levels in patients with primary hyperoxaluria. We report compassionate use of O formigenes in two 11-month-old girls with infantile oxalosis and ESRD. They received O formigenes twice a day for 4 weeks (or until transplant). Dialysis regimens were unchanged. Plasma oxalate levels decreased from >110 μmol/L before to 71.53 μmol/L under treatment in patient 1 and from >90 to 68.56 μmol/L (first treatment period) and 50.05 μmol/L (second treatment period) in patient 2. O formigenes was well tolerated. No serious side effects were reported. Extremely increased plasma oxalate levels in patients with infantile oxalosis may enable intestinal elimination of endogenous oxalate in the presence of O formigenes. Therefore, O formigenes therapy may be helpful as a bridging procedure until transplant in such patients.

Topics: Administration, Oral; Feces; Female; Humans; Hyperoxaluria; Hyperoxaluria, Primary; Infant; Kidney Transplantation; Mutation, Missense; Nephrocalcinosis; Oxalates; Oxalobacter formigenes; Renal Insufficiency; Transaminases

Exposure to high levels of oxalate and calcium oxalate monohydrate (COM) crystals is injurious to renal epithelial cells and triggers serial responses related to stone formation. Multiple molecules and proteins are involved in this process, but previous studies have generally been limited, without an overall understanding of protein expression alteration after oxalate and/or crystal exposure as well as its role in stone formation. We used proteomic analysis to reveal the changes in the proteome of HK-2 cells induced by oxalate and COM crystals, so as to provide candidate proteins involved in the molecular mechanisms concerning HK-2 cell injury and kidney stone formation. HK-2 cells were exposed to oxalate plus COM crystals at different concentrations in various samples. Cell viability was determined using a Cell Counting Kit-8 assay kit. For proteomic analysis, cells were exposed to oxalate (2 mM) and COM crystals (200 ug/ml) for 12 h. The proteins were separated by two-dimensional electrophoresis and the differentially expressed proteins were identified by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Validation of protein expression was further performed by Western blot analysis. Oxalate and COM crystals showed concentration-dependent toxicity on HK-2 cells. A total of 12 differentially expressed proteins in HK-2 cells induced by oxalate and COM crystals were identified, which were involved in various aspects of cellular processes. Our study provides a platform for further studying the molecular mechanism of renal epithelial cell injury and kidney stone formation.

Topics: Calcium Oxalate; Cells, Cultured; Crystallization; Epithelial Cells; Humans; Kidney Calculi; Kidney Tubules, Proximal; Oxalates; Proteomics; Renal Insufficiency

Primary hyperoxaluria type 1 (PH1) is a rare autosomal recessive metabolic disorder resulting in the overproduction of plasma oxalate. Although the enzymatic defect is in hepatocyte peroxisomes, uncontrolled levels of oxalate result in calcium oxalate deposition in multiple organs. Because the primary route of elimination of oxalate is renal excretion, high levels are found in urine, which results in supersaturation and crystal nucleation. Patients typically present with recurrent nephrolithiasis and nephrocalcinosis. If not diagnosed early, end-stage renal disease (ESRD) and systemic calcium oxalate deposition can occur. Once ESRD develops, intensive dialysis therapy is unable to keep pace with the high oxalate production, and the preferred therapeutic intervention is combined kidney-liver transplantation. Here, we report a young man with a history of recurrent nephrolithiasis who presented to us with ESRD and subsequently developed manifestations of systemic oxalosis. The diagnosis of PH1 must be considered in the differential diagnosis of patients presenting with ESRD with a history of recurrent nephrolithiasis. The diagnosis of PH1 is more challenging in patients with ESRD, for whom urinary oxalate levels are often normal or only modestly increased because of decreased glomerular filtration, and recurrent nephrolithiasis is no longer the dominant clinical feature.

Topics: Adult; Diagnosis, Differential; Humans; Hyperoxaluria, Primary; Male; Oxalates; Renal Dialysis; Renal Insufficiency

The primary goal of this study was to test the hypothesis that Oxalobacter colonization alters colonic oxalate transport thereby reducing urinary oxalate excretion. In addition, we examined the effects of intraluminal calcium on Oxalobacter colonization and tested the hypothesis that endogenously derived colonic oxalate could be degraded by lyophilized Oxalobacter enzymes targeted to this segment of the alimentary tract. Oxalate fluxes were measured across short-circuited, in vitro preparations of proximal and distal colon removed from Sprague-Dawley rats and placed in Ussing chambers. For these studies, rats were colonized with Oxalobacter either artificially or naturally, and urinary oxalate, creatinine and calcium excretions were determined. Colonized rats placed on various dietary treatment regimens were used to evaluate the impact of calcium on Oxalobacter colonization and whether exogenous or endogenous oxalate influenced colonization. Hyperoxaluric rats with some degree of renal insufficiency were also used to determine the effects of administering encapsulated Oxalobacter lysate on colonic oxalate transport and urinary oxalate excretion. We conclude that in addition to its intraluminal oxalate-degrading capacity, Oxalobacter interacts physiologically with colonic mucosa by inducing enteric oxalate secretion/excretion leading to reduced urinary excretion. Whether Oxalobacter, or products of Oxalobacter, can therapeutically reduce urinary oxalate excretion and influence stone disease warrants further investigation in long-term studies in various patient populations.

Topics: Animals; Biological Transport; Calcium; Colon; Creatinine; Intestinal Mucosa; Intestines; Male; Nephrectomy; Oxalates; Oxalobacter formigenes; Probiotics; Rats; Rats, Sprague-Dawley; Renal Insufficiency; Urinary Calculi

The Zellweger spectrum disorders (ZSDs) are characterized by a generalized loss of peroxisomal functions caused by deficient peroxisomal assembly. Clinical presentation and survival are heterogeneous. Although most peroxisomal enzymes are unstable in the cytosol of peroxisome-deficient cells of ZSD patients, a few enzymes remain stable among which alanine:glyoxylate aminotransferase (AGT). Its deficiency causes primary hyperoxaluria type 1 (PH1, MIM 259900), an inborn error of glyoxylate metabolism characterized by hyperoxaluria, nephrocalcinosis, and renal insufficiency. Despite the normal level of AGT activity in ZSD patients, hyperoxaluria has been reported in several ZSD patients. We observed the unexpected occurrence of renal stones in a cohort of ZSD patients. This led us to perform a study in this cohort to determine the prevalence of hyperoxaluria in ZSDs and to find clinically relevant clues that correlate with the urinary oxalate load. We reviewed medical charts of 31 Dutch ZSD patients with prolonged survival (>1 year). Urinary oxalate excretion was assessed in 23 and glycolate in 22 patients. Hyperoxaluria was present in 19 (83%), and hyperglycolic aciduria in 14 (64%). Pyridoxine treatment in six patients did not reduce the oxalate excretion as in some PH1 patients. Renal involvement with urolithiasis and nephrocalcinosis was present in five of which one developed end-stage renal disease. The presence of hyperoxaluria, potentially leading to severe renal involvement, was statistically significant correlated with the severity of neurological dysfunction. ZSD patients should be screened by urinalysis for hyperoxaluria and renal ultrasound for nephrocalcinosis in order to take timely measures to prevent renal insufficiency.

Topics: Adolescent; Child; Child, Preschool; Cohort Studies; Glycolates; Humans; Hyperoxaluria; Infant; Kidney Calculi; Oxalates; Renal Insufficiency; Retrospective Studies; Zellweger Syndrome

Many aspects of calcium oxalate (CaOx) deposition in renal transplant biopsies are not known. Review of all renal transplant biopsies performed in a 7-year period showed that CaOx deposition could be classified into three groups. Group I: Seven biopsies within a month post-transplant displayed rare CaOx foci against a background of acute tubular necrosis or acute cell-mediated rejection. At follow-up, five grafts functioned well and two failed due to chronic allograft nephropathy. CaOx in this context was an incidental finding secondary to a sudden excretion of an end-stage renal disease-induced increased body burden of CaOx. Group II: Two biopsies performed 2 and 10 months post-transplant showed rare CaOx foci against a background of chronic allograft nephropathy, leading to graft loss. CaOx in this context reflected nonspecific parenchymal deposition due to chronic renal failure regardless of causes. Group III: One biopsy with recurrent PH1 characterized by marked CaOx deposition associated with severe tubulointerstitial injury and graft loss 6 months post-transplant. There were two previously reported cases in which CaOx deposition in the renal allografts was due the antihypertensive drug naftidrofuryl oxalate or increased intestinal absorption of CaOx. CaOx deposition in renal allografts can be classified in different categories with distinctive morphologic features and clinical implications.

Topics: Absorption; Adolescent; Adult; Aged; Biopsy; Cadaver; Calcium Oxalate; Creatinine; Female; Graft Rejection; Humans; Kidney Transplantation; Kidney Tubules; Living Donors; Male; Middle Aged; Nafronyl; Necrosis; Oxalates; Renal Insufficiency; Time Factors; Transplantation, Homologous; Vasodilator Agents

Primary hyperoxaluria type I may initially manifest as urolithiasis, renal insufficiency, or symptoms of systemic oxalosis. This hereditary disorder was fatal until effective therapies evolved during the past two decades. Difficulty in recognizing and diagnosing this disorder in adults is illustrated in a report of a patient eventually restored to good health by high-flux dialysis and combined renal and hepatic transplantation. I explore the molecular processes of the genetic defect and discuss clinical indicators of primary hyperoxaluria type I, manifestations of oxalosis, the pathogenesis of chronic oxalate nephropathy, and the diagnosis and management of this disease.

Topics: Humans; Hyperoxaluria, Primary; Male; Middle Aged; Oxalates; Renal Insufficiency; Urinary Calculi

The authors reported ten cases of familial nephropathy (two cystinosis, three Senior and Loken syndrome, one Alport's syndrome and four Oxalosis) associated to ocular manifestations. Aetiologic diagnosis was known from ocular symptoms in five cases (all cases of cystinosis and Senior and Loken syndrome). The authors undertook this study to analyse the value of ocular manifestations in determining the right aetiologic diagnosis in familial nephropathies. The results of this study showed that ocular manifestations are helpful for aetiologic diagnosis in the first diseases. Indeed, corneal injury is synonym of cystinosis and retinitis pigmentosa is usually associated with Senior and Loken syndrome. In Alport's syndrome, ocular manifestations: antcrior lenticonus cataractous and perimacular white points only have orientation value in the diagnosis of this disease. Oxalosis ocular manifestations which consist of retinal oxalate deposits appear late and are concomitant to familial renal insufficiency. They cannot help in the diagnostic search.

Topics: Adolescent; Child; Corneal Diseases; Cystinosis; Eye Diseases; Humans; Kidney Diseases; Nephritis, Hereditary; Oxalates; Renal Insufficiency; Retinal Diseases; Retinitis Pigmentosa

Topics: Acute Kidney Injury; Glomerulonephritis; Heart Diseases; Hyperkalemia; Hyperoxaluria; Kidney; Kidneys, Artificial; Oxalates; Pyelonephritis; Renal Insufficiency; Shock, Hemorrhagic; Shock, Traumatic; Toxicology; Uremia

Topics: Acute Kidney Injury; Child; Humans; Hyperoxaluria; Infant; Kidney Calculi; Nephrolithiasis; Oxalates; Renal Insufficiency; Urinary Calculi

Topics: Child; Dwarfism; Humans; Hyperoxaluria; Infant; Kidney; Medical Records; Metabolic Diseases; Nephrocalcinosis; Oxalates; Renal Insufficiency