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PubMed1976

[Primary hyperoxaluria. Clinical, histological and crystallographic study of the ocular lesions].

A post-mortem histological examination of the eyes of a case of primary hyperoxaluria revealed the presence of crystals in the ciliary processes and at the level of the retinal pigment epithelium. The crystallography study demonstrated that it consisted of wewhellite. The ocular lesions are compared with those found by other authors in primary hyperoxaluria, after prolonged methoxyflurane anaesthesia, after experimental administration of dibutyloxalic acid or naphthalene, and in the human retina in longstanding detachments. Most of the factors which give rise to the presence in the eye of oxalate and its selective precipitation in the midst of certain ocular tissues remain hypothetical. The retinal lesions observed in primary hyperoxaluria appear to be pathognomonic for hyperoxalaemia.

Adult↗
PubMed1978

Prolonged survival after renal transplantation in primary hyperoxaluria of childhood.

Cadaver renal transplantation was performed in a 14-year-old girl with primary hyperoxaluria. Acute tubular necrosis was present initially, and a moderate rejection crisis occurred at 6 weeks. Renal biopsy performed at 4 months showed considerable deposition of calcium oxalate. Urinary excretion of oxalate varied between 315-371 mg/24 hr per 1.73 m2 (normal less than 50 mg). Despite these unfavourable factors, renal function has remained stable for the last 2 1/2 years; the serum creatinine is 1.5 mg/100 ml at 3 years. This is the longest surviving graft reported so far in documented primary hyperoxaluria. Graft failures in previous reports could in part be explained by additional complicating factors. It is concluded that renal transplantation is not necessarily contraindicated in primary hyperoxaluria.

Adolescent↗
PubMed1983

Complex pathogenesis of hyperoxaluria after jejunoileal bypass surgery. Oxalogenic substances in diet contribute to urinary oxalate.

Balance studies and oxalate loading tests were carried out in order to define the pathogenesis of hyperoxaluria in 8 patients with jejunoileal bypass surgery for severe obesity; two healthy volunteers were also studied. In the bypass patients, urinary oxalate was markedly elevated (118 +/- 43 mg/day, mean +/- SD) when they were on a high oxalate diet (252 mg/day). Hyperabsorption of dietary oxalate was confirmed by the markedly increased urinary recovery of [14C]oxalate given in a test meal. In addition, the oxalate radioactivity was excreted in urine far more slowly than in healthy volunteers, suggesting that the colon was a major site of oxalate absorption. Elevated urinary oxalate excretion persisted, averaging 38 +/- 12 mg/day, despite ingestion of a very low oxalate diet (approximately 6 mg/day), suggesting that the diet contained "oxalogenic" substances other than preformed dietary oxalate which also contributed to dietary oxalate in these patients. Urinary oxalate decreased in 7 of 8 patients, however, when protein-rich foods were removed from the diet, suggesting that at least one dietary factor was digestive products of protein or creatinine. These results confirm the current view that in patients with hyperoxaluria secondary to jejunoileal bypass, the majority of urinary oxalate derives from dietary oxalate that is absorbed from the colon. Tissue or bacterial production of oxalate or an oxalate precursor from dietary constituents associated with protein, however, also appears to contribute to urinary oxalate. The results provide an explanation for the reported difficulty of eliminating secondary hyperoxaluria by restriction of dietary oxalate alone.

Adult↗
PubMed1977

'Enteral' hyperoxaluria. Effect of cholestyramine, calcium, neomycin, and bile acids on intestinal oxalate absorption in man.

The effect of oral administration of cholestyramine, neomycine, calcium, and bile acids on intestinal 14C-oxalate absorption and urinary oxalate excretion was assessed in patients with normal or increased ('enteric' hyperoxaluria) urinary oxalate excretion. Cholestyramine, neomycine and acute administration of chenodeoxycholic acid (2.75 g/24 h) did not affect significantly 14C-oxalate absorption or urinary oxalate excretion. Oral administration of calcium markedly reduced 14C-oxalate absorption (88.2%) and urinary oxalate excretion (46%). Calcium-induced reduction of intestinal oxalate absorption was more pronounced in patients with hyperabsorption of oxalate than in subjects with normal oxalate absorption or excretion. Patients on treatment with high doses of chenodeoxycholic acid (1.5-2.0 g/day) for dissolution of cholesterol gallstones had increased oxalate absorption and excretion, patients on long-term treatment with lower doses of chenodeoxycholic acid (0.75-1.0 g/day) exhibited normal absorption or urinary excretion of oxalate. The results do suggest that calcium and bile acids do play an important role in the pathogenesis of 'enteric' hyperoxaluria. It is suggested that the beneficial therapeutic effect of cholestyramine in hyperoxaluria due to ileal resection is rather caused by its bile acid binding property than by direct binding of oxalate within the intestinal lumen.

Bile Acids and Salts↗
PubMed1989

Fetal liver alanine: glyoxylate aminotransferase and the prenatal diagnosis of primary hyperoxaluria type 1.

Primary hyperoxaluria type 1 (PH1) is caused by a deficiency of the hepatic peroxisomal enzyme alanine: glyoxylate aminotransferase (AGT, EC 2.6.1.44) (Danpure and Jennings, FEBS Lett., 201, 20-24, 1986). The activity of AGT has been measured in fetal livers of gestational age 14-21 weeks. Activity increases up to 17 weeks and then levels off between 17 and 21 weeks. At this time, the mean AGT activity is about 30 per cent of the mean normal postnatal level. As in adult liver, the AGT enzyme activity and the AGT immunoreactive protein are peroxisomal. Prenatal diagnosis has been performed by measuring AGT enzyme activity and immunoreactive AGT protein on liver biopsies from two fetuses at risk for primary hyperoxaluria type 1. One was unaffected and one was affected.

Alanine Transaminase↗
PubMed1989

Bone disease of primary hyperoxaluria in infancy.

A patient with primary hyperoxaluria type I in infancy is reported. He had renal insufficiency, but urolithiasis was absent. Demonstration of diffuse nephrocalcinosis by renal ultrasound contributed to early diagnosis. Prolonged survival leads to extensive extrarenal oxalate deposition. Repeated skeletal surveys showed the development and the progression of severe hyperoxaluria-related bone disease. Translucent metaphyseal bands with sclerotic margins, wide areas of rarefaction at the ends of the long bones, and translucent rims around the epiphyses and the tarsal bones were signs of disordered bone growth. Bone density generally increased with time indicating progressive sclerosis due to oxalate deposition in the previously normal bone structure.

Bone Diseases, Metabolic↗
PubMed1989

Periodontal manifestations of hyperoxaluria and oxalosis.

Dental and periodontal findings associated with primary hyperoxaluria in a 29-year old male patient are described. This is a rare, inherited, metabolic disease which results in excessive calcium oxalate synthesis. The predominant and early manifestation of hyperoxaluria is nephrocalcinosis which results in chronic renal failure. Widespread extrarenal deposits of calcium oxalate crystals, however, is a consistent finding. Extensive infiltration of crystals was noted in the pulps of the teeth, in the marrow spaces of the alveolar bone, in the gingival corium, and in the periodontal ligament. Crystalline calcium oxalate deposits in the periodontal ligament provoked a granulomatous foreign-body reaction. This resulted in aggressive external root resorption leading to pulp exposure and tooth mobility.

Adult↗
PubMed1989

Vitamin B6 resistant primary hyperoxaluria type I. Report of 5 cases.

Primary hyperoxaluria type I (PH I) is characterized by an excessive endogenous production and excretion of oxalic and glycolic acid. Prognosis of this "inborn error of metabolism" is not favorable due to calcium-oxalate depositions in kidney and other organs. Vitamin B6 administration and/or renal transplantation can greatly improve the prognosis, as reported in literature. In this article our experience with 5 patients with vitamin B6 resistant hyperoxaluria is reported. Symptomatology and progression of the primary disease are described. The results of treatment interfering with oxalate production and calcium-oxalate crystallization are given. Three patients underwent renal replacement therapy. In these, oxalosis developed during hemodialysis and progressed following transplantation; a disabling bone disease was the most severe complication. Outcome of transplantation was disappointing. In two out of three patients, there was recurrence of the primary disease in the graft. In only one of them long-term graft function was satisfying. However, even this good function could not prevent disabling symptoms of oxalosis. Therefore, evaluation of the results of transplantation should not only include data related to graft function and survival, but also the complications due to calcium-oxalate depositions in various organs. To prevent oxalosis, kidney transplantation should be performed before end stage renal disease is achieved in patients with vitamin B6 resistant PH I.

Child↗
PubMed1987

Renal transplantation in primary hyperoxaluria.

The increased production and excretion of oxalate in primary hyperoxaluria causes urolithiasis, nephrocalcinosis with renal failure, and systemic oxalosis. Systemic oxalosis occurs late in the course of the disease when there is both oxalate retention and increased oxalate synthesis. The uraemia can be controlled by conventional haemodialysis or peritoneal dialysis but treatment cannot usually keep up with accelerated rate of oxalate production, and dialysed patients develop systemic oxalosis. Most attempts to treat primary hyperoxaluria by renal transplantation have been unsuccessful because of rapid recurrence of nephrocalcinosis with uraemia and systemic oxalosis. Dynamic studies of overall oxalate metabolism in vivo have shown that the renal retention factor becomes a major determinant of oxalosis when the GFR decreases to less than 25 ml min-1 1.73 m-2. We conclude provisionally that vigorous haemodialysis should be begun and transplantation arranged when the GFR reaches this level. Such early transplantation with vigorous perioperative haemodialysis and a large perioperative diuresis of water gives good immediate graft function and oxalate mobilisation from the miscible oxalate pool. The longer term outlook is then influenced more by the factors which determine the success of renal transplantation in non-hyperoxaluric patients.

Glomerular Filtration Rate↗
PubMedDate not supplied

Biochemical approach to diagnosis and differentiation of primary hyperoxalurias: an update.

The hyperoxaluria syndromes can be differentiated by the assessment of associated abnormalities in generation and urine excretion of metabolically related molecules. Based on the experience gained in our laboratory during the last decade, we have developed a comprehensive diagnostic work-up, which includes measurements of oxalate, glycolate and L-glycerate in plasma, urine and dialysis fluids, and an assay for AGT activity on liver biopsy. The availability of reliable assays for each of these parameters is indispensable for the recognition and differentiation of hyperoxalurias. Patients suspected to have abnormalities in oxalate metabolism are first screened by analysing spot urines and serum, and subsequently are subjected to more extensive studies using properly pre-treated blood samples and 24-hour urine collection. AGT activity, in the case of PH1, is assayed on few milligrams liver specimen by using a sensitive chromatographic procedure. Pertinent biochemistries will also assist in the long-term medical follow-up of these patients and in view of the choice of renal replacement or transplantation strategies.

Diagnosis, Differential↗
PubMed1991

Ocular histopathologic findings in a 46-year-old man with primary hyperoxaluria.

A 46-year-old Japanese man with familial primary hyperoxaluria had been suffering from urolithiasis since the age of 6 years and had been treated by hemodialysis for 8 years before his death. The alpha-ketoglutarate glyoxylate carboligase and serine pyruvate transoxylase activities in the patient's liver had markedly decreased, indicating type I primary hyperoxaluria. Ocular tissues obtained at autopsy were studied immunohistochemically and histochemically. The ocular alterations were characterized by an unusual distribution of oxalate deposits, mainly located in the outer plexiform layer and the nuclear layer but not in the retinal pigment epithelium or in the vascularized layer of the sensory retina. These distributions of the oxalate deposits were determined to be unrelated to the blood vessels.

Blood Chemical Analysis↗
PubMed1981

Effective therapy of enteric hyperoxaluria: in vitro binding of oxalate by anion-exchange resins and aluminum hydroxide.

Hyperabsorption of dietary oxalate is a major factor in the pathogenesis of enteric hyperoxaluria and a frequent complication of inflammatory bowel disease and ileojejunal bypass surgery. Successful treatment requires reduction in oxalate intake or inhibition of absorption of dietary oxalate by oral ingestion of oxalate binding agents. To identify such agents, oxalate binding by anion-exchange resins, gums, and aluminum hydroxide was measured under conditions that simulated those present in the intestinal lumen. Of the agents tested, those that bound oxalate best were colestipol and aluminum hydroxide. Strongly basic anion-exchange resins readily bound oxalate only in the absence of chloride. These results suggest that colestipol and aluminum hydroxide administration might reduce dietary oxalate absorption in patients with enteric hyperoxaluria.

Adsorption↗
PubMed2003

Angiotensin II involvement in adaptive enteric oxalate excretion in rats with chronic renal failure induced by hyperoxaluria.

UNLABELLED: Enteric secretion of oxalate is induced in rats that have chronic renal failure produced by 5/6 nephrectomy. The purpose of the present study was to examine renal and intestinal handling of oxalate in rats with chronic renal failure (CRF) induced by chronic hyperoxaluria. A rat model for chronic renal failure, induced by chronic hyperoxaluria (CH-CRF), was produced by unilateral nephrectomy combined with dietary ethylene glycol for 4 weeks. Both intact and unilateral nephrectomized rats (UN) without the oxalate load served as controls. Renal handling of oxalate was assessed by measurement of renal clearance of oxalate and creatinine while colonic handling of oxalate and chloride was determined by in vitro transepithelial flux measurements. Angiotensin II mediation was assessed by sensitivity of the transport processes to the AT(1) receptor antagonist losartan. Renal and colonic handling of oxalate in UN rats were similar to intact controls. The CH-CRF rats were hyperoxalemic, hyperoxaluric, and exhibited a twofold increase in oxalate clearance despite a 50% drop in creatinine clearance. Distal (but not proximal) colonic handling of oxalate in CH-CRF rats was reversed from net oxalate absorption seen in UN and intact controls to net secretion that was sensitive to losartan in vitro. CONCLUSION: Although enteric oxalate secretion can be correlated with elevations in plasma oxalate in the absence of overt renal insufficiency by an ANG II-independent mechanism, the present results suggest that some degree of renal insufficiency is necessary to induce ANG II-mediated colonic oxalate secretion.

Adaptation, Physiological↗
PubMed2005

Pitfalls in the management of patients with primary hyperoxaluria: a urologist's perspective.

The primary hyperoxalurias are rare, inherited diseases which commonly manifest early in life as urolithiasis. As these patients often present to the urologic surgeon, it is imperative that urologists understand the typical presentation, diagnosis, and management of urolithiasis associated with primary hyperoxaluria. In this review, the pertinent epidemiology and pathogenesis as they relate to the diagnosis and natural history of the disease are discussed. The literature on therapeutic options for primary hyperoxaluric patients with calculi is examined, and treatment strategies are suggested.

Humans↗
PubMed2005

An overview of the role of genotyping in the diagnosis of the primary hyperoxalurias.

The aim of this paper is to give an overview of our current state of knowledge with respect to genotyping for the primary hyperoxalurias and the role of molecular genetics alongside the more traditional biochemical and enzymatic tests for the diagnosis and prognosis of these disorders. The published literature was reviewed to establish the frequency of different mutations and thus the value of testing for a limited number of these mutations in patients with clinical suspicion of primary hyperoxaluria (PH). This approach was compared with whole gene sequencing of the AGXT and GRHPR genes. A limited genetic screen can provide a first line test for PH1 and PH2 in symptomatic patients and can provide a full diagnosis in approximately a third of cases. Molecular genetic analysis is essential for carrier testing and prenatal diagnosis. The value of molecular genetics in prognosis requires a wider evidence base.

Genotype↗
PubMed2005

The role of preemptive liver transplantation in primary hyperoxaluria type 1.

In primary hyperoxaluria the deficiency or mistargeting of hepatic alanine-glyoxylate aminotransferase (AGT) leads to the overproduction of oxalate resulting in hyperoxaluria and renal damage due to urolithiasis and/or nephrocalcinosis. Presently, the cure of the metabolic defect can be achieved only by liver transplantation. While for patients with end-stage renal disease combined hepatorenal transplantation is recommended, the concept of preemptive liver transplantation (PLTX), i.e. cure of the metabolic defect before renal damage occurs, has received considerable attention. Due to the heterogenous clinical course in PH1, optimal timing of PLTX is a matter of debate. Advocators of PLTX would consider a patient with a slowly declining GFR, reaching levels of 40-60 ml/min/1.73 m(2), as an ideal candidate, while others would continue medical treatment in these patients and opt for rapid combined liver-kidney transplantation if GFR reaches even lower levels. This review will discuss the background and rationale of PLTX and gives an update on 11 patients with PLTX who have been reported in the literature to date.

Humans↗
PubMed1999

Primary hyperoxaluria 1: catch up growth and normalization of oxaluria 6 years after hepatorenal transplantation in a prepubertal boy.

We present data on urinary oxalate (U(OX)), renal function, growth and bone age in a 10-year-old male with primary hyperoxaluria type 1. The patient had undergone combined liver-kidney transplantation at the age of 4.5 years. UOX increased up to 10(4) micromol/24 h after transplantation and declined to normal values thereafter. Excessive Uox concentrations after surgery might have been due to a bone pool of unsoluble oxalate and declined spontaneously. Creatinine clearance remained stable during observation period. The boy showed significant catch up growth. Height standard deviation score for chronological age improved from -2.4 before transplantation to -0.3 after 6 years. Radiological bone density improved at the same time. Hepatorenal transplantation should be performed in children with primary hyperoxaluria 1 before end-stage renal failure to normalize oxalate excretion and improve growth and bone mineralization.

Bone Density↗
PubMed2002

Primary hyperoxaluria type 2 in children.

The primary hyperoxalurias (PH1 and PH2) are rare defects of oxalate overproduction. There are only 24 reported cases of PH2, which is characterized by raised urine oxalate and L-glycerate. We describe 13 previously unreported children with PH2, representing the largest single-centre cohort in the world. DNA samples were tested for a common mutation and four other documented mutations in the gene encoding the enzyme glyoxylate reductase/hydroxypyruvate reductase (GRHPR). Two of the five kindred showed homozygosity for two different mutations in the GRHPR gene. The genetic defect was not identified in the other three families. The median age at diagnosis of PH2 was 1.7 years. Five children presented with nephrolithiasis between 0.8 and 9 years. Haematuria was common, but urinary tract infection and nephrocalcinosis were not. All had normal renal function at diagnosis, and only 1 patient had a significant decline in glomerular filtration rate. We conclude that all children with nephrolithiasis secondary to hyperoxaluria should have urinary glycerate measured, as PH2 may be more prevalent than currently estimated. DNA mutational analysis may be useful in supporting the diagnosis.

Adolescent↗