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PubMed1976

Senior-Loken syndrome (nephronophthisis and tapeto-retinal degeneration): a study of 8 cases from 5 families.

The association of nephronophthisis and tapeto-retional degeneration was described by both Senior and Loken in 1961, but prior to 1974 only 28 cases had been published. This report describes 8 new cases in 27 members of 5 families. The severe juvenile type produces blindness in infancy and death from renal failure before the age of ten. The adult type is characterized by later onset, slower progression of the renal disease and milder ocular manifestations. The eye disease may be congenital amaurosis of Leber type, pigmentary retinal degeneration or retinitis punctata albescens and the electroretinogram (ERG) is of value in the diagnosis of these varieties of hereditary tapeto-retinal degeneration. Renal involvement is often asymptomatic. Defective urinary concentration leading to polyuria and polydipsia is the earliest sign. Proteinuria is inconstant and urinary sediment is often normal. Two patients had aminoaciduria. The disease progresses inexorably to chronic renal failure. One patient has been successfully transplanted and two others are on chronic hemodialysis. Renal histological changes are those of nephronophthisis with tubulointerstitial lesions and multiple cysts. Senior-Loken syndrome appears to be transmitted by a single autosomal recessive pleotropic gene of variable expression. Degeneration of neuroepithelium and renal tubular epithelium, both tissues of ectodermal origin, may represent a genetically determined enzyme abnormality.

Adolescent↗
PubMed1991

Free amino acids during chronic cyclosporine A toxicity in intact and partially nephrectomized rats.

The effects of 40 days of treatment with Cyclosporine A (CSA) on plasma and urine free amino acids were investigated in sham-operated (C) and partially nephrectomized (Pnx) female Fischer 344 rats. High Dose CSA (30 mg/kg/day ip) was associated with reduced weight gain, increased plasma urea nitrogen, and hypoproteinemia in C and Pnx animals. These animals also demonstrated increased plasma levels of alanine, markedly reduced levels of tryptophan, and an increase in urinary excretion of methylhistidines. C but not Pnx animals also showed a significant increase in plasma serine and a decrease in plasma taurine. CSA treatment of group C resulted in a progressive aminoaciduria involving substrates of the neutral and acidic renal amino acid transport systems; however, the renal excretion of taurine and beta-alanine by these animals was markedly reduced as compared to vehicle treated controls. High dose CSA exacerbated aminoaciduria in Pnx animals, but in this group, the excretion of beta amino acids was also increased. Our findings demonstrate that chronic CSA toxicity in rodents with normal renal function is characterized by increased muscle protein catabolism, significant reductions in plasma tryptophan, and an apparent decrease in whole body taurine pools. With the exception of the taurine abnormalities. CSA treatment had similar effects on Pnx animals; however, in this group, CSA-induced pathological changes were superimposed on the changes due to renal insufficiency per se. CSA toxicity as identified by the parameters investigated in this study was no more severe in Pnx animals with moderate chronic renal insufficiency than in controls with intact renal function.

Alanine↗
PubMed1986

Paper chromatography of urinary amino acids. A 30 year survey of dietary influences on the normal pattern, and patients' results.

In the clinical laboratory, paper chromatography is still the most useful, simple, inexpensive procedure for initial identification of abnormalities of amino acid excretion. The results of its use for more than 8000 paediatric and adult renal patients is surveyed. Nonspecific generalized aminoaciduria was the most frequent abnormality found, comprising some 70% of abnormal results, with cystine-lysinuria the next most common. The identification of the abnormal excretory pattern of amino acids as distinct from the normal was complicated by the effects of the New Zealand diet. In particular, valine, citrulline, hydroxyproline and glutamic acid are found in considerable amounts as part of the normal pattern. Their dietary origin is discussed. Varying mixtures of monosaccharides and disaccharides occurred in association with a range of amino acid patterns.

Adult↗
PubMed2003

Regulation of renal amino acid (AA) transport by hormones, drugs and xenobiotics - a review.

Major advances have recently been made in our understanding of the mechanisms and functions of amino acid transport in mammalian cells: - from the whole organism to transporter molecular structure. In this article, we present a brief overview of current knowledge concerning amino acid transporters, followed by a detailed discussion of the relevance of this new information to our broader understanding of the physiological regulation of amino acid handling in the kidney. We focus especially on the influence of hormones and xenobiotics on renal amino acid transport systems. In a growing number of cases, it now seems possible to correlate the effects of hormones, drugs, and xenobiotics with the capacity of renal amino acid transporters. This topic is of clinical relevance for the treatment of many amino acid reabsorption disorders. For example, under suitable conditions glucocorticoids and thyroid hormones stimulate renal reabsorption of amino acids and might therefore be of benefit in the treatment of different kinds of aminoaciduria. Hormonal regulation also underlies the postnatal development of renal amino acid reabsorption capacity, which can be stimulated to mature earlier after exogenous administration of e.g. glucocorticoids. In contrast, many compounds (e.g. heavy metal complexes) selectively damage renal amino acid transporters resulting in urinary amino acid loss. These types of phenomena (stimulation or inhibition of amino acid transporters in the kidney) are reviewed from the perspectives of our new molecular understanding of transport processes and of clinical relevance.

Amino Acids↗
PubMed1986

Wilson's disease revisited in the tropics.

The clinical features and investigations of 17 patients were analysed. Thirteen of them were Chinese and the rest Indians. Their ages at presentation ranged from 8 to 63 years (mean 18.35 years). Thirteen patients (76%) were symptomatic; 8 with predominantly hepatic manifestations and 5 with neurological features. Four were asymptomatic siblings. At diagnosis, however, 10(59%) had features of liver involvement singly, 3 (18%) had neurological involvement alone and 4 (27%) had mixed presentations. Family histories were available in 15 patients; 26.9% of siblings had Wilson's Disease. Serum ceruloplasmin was low in 82% of the patients. 24-hour urinary copper was measured in 16 patients and was raised in all of them. About half the patients (41%) had evidence of concomittant renal tubular dysfunction with hypouricaemia and aminoaciduria. Three patients (18%) had joint involvement at presentation. All 17 patients were treated with Penicillamine. Complications due to therapy included pemphigus in one and toxic epidermal necrolysis and later a lupus like syndrome in another. The features of clinical improvement included fading of K-F rings, improvement of neurological signs and the normalisation of serum transaminases. One patient developed primary hepatocellular carcinoma 5 years after presentation. Delay in diagnosis was encountered in half of the patients reviewed. Being a treatable condition, Wilson's Disease, although rare, should always be thought of in patients with haemolysis, liver diseases or extrapyramidal disorders.

Adolescent↗
PubMed1996

[Idiopathic Fanconi syndrome in an adult].

Fanconi syndrome is a complex destruction of proximal renal tubuli which leads to glycosuria, aminoaciduria, phosphaturia and uraemia. These disturbances are accompanied with hypophosphatemia, osteomalacia and frequently hypokalemia. A 32-yrs. old woman diagnosed as suffering for 10 yrs. with Fanconi syndrome was admitted to the clinic with pain and numbness of the right leg which made walking difficult this resulted from progressive bone destruction. Biochemical disturbances and osteomalacia which are typical for Fanconi syndrome was confirmed in 1984. The reason for 3 hospitalizations in 1990-1992 were similar--especially leg pain and symptoms of uraemia. Recent X-rays showed osteomalacia with osteoporosis and progressive bone destruction. After she was put on a uremic diet, given vitamin D, calcium, phosphorus and sodium bicarbonate, there was a significant decrease in leg pain and relatively normal biochemical parameters.

Adult↗
PubMed1996

Obligatory amino acid exchange via systems bo,+-like and y+L-like. A tertiary active transport mechanism for renal reabsorption of cystine and dibasic amino acids.

Mutations in the rBAT gene cause type I cystinuria, a common inherited aminoaciduria of cystine and dibasic amino acids due to their defective renal and intestinal reabsorption (Calonge, M. J., Gasparini, P., Chillarón, J., Chillón, M., Gallucci, M., Rousaud, F., Zelante, L., Testar, X., Dallapiccola, B., Di Silverio, F., Barceló, P., Estivill, X., Zorzano, A., Nunes, V., and Palacín, M. (1994) Nat. Genet. 6, 420-426; Calonge, M. J., Volipini, V., Bisceglia, L., Rousaud, F., De Sanctis, L., Beccia, E., Zelante, L., Testar, X., Zorzano, A., Estivill, X., Gasparini, P., Nunes, V., and Palacín, M.(1995) Proc. Natl. Acad. Sci. U. S. A. 92, 9667-9671). One important question that remains to be clarified is how the apparently non-concentrative system bo,+-like, associated with rBAT expression, participates in the active renal reabsorption of these amino acids. Several studies have demonstrated exchange of amino acids induced by rBAT in Xenopus oocytes. Here we offer evidence that system bo,+-like is an obligatory amino acid exchanger in oocytes and in the "renal proximal tubular" cell line OK. System bo, +-like showed a 1:1 stoichiometry of exchange, and the hetero-exchange dibasic (inward) with neutral (outward) amino acids were favored in oocytes. Obligatory exchange of amino acids via system bo,+-like fully explained the amino acid-induced current in rBAT-injected oocytes. Exchange via system bo,+-like is coupled enough to ensure a specific accumulation of substrates until the complete replacement of the internal oocyte substrates. Due to structural and functional analogies of the cell surface antigen 4F2hc to rBAT, we tested for amino acid exchange via system y+L-like. 4F2hc-injected oocytes accumulated substrates to a level higher than CAT1-injected oocytes (i.e. oocytes expressing system y+) and showed exchange of amino acids with the substrate specificity of system y+L and L-leucine-induced outward currents in the absence of extracellular sodium. In contrast to L-arginine, system y+L-like did not mediate measurable L-leucine efflux from the oocyte. We propose a role of systems bo,+-like and y+L-like in the renal reabsorption of cystine and dibasic amino acids that is based on their active tertiary transport mechanism and on the apical and basolateral localization of rBAT and 4F2hc, respectively, in the epithelial cells of the proximal tubule of the nephron.

Amino Acid Transport Systems, Basic↗
PubMed1967

Aminoaciduria resulting from cycloleucine administration in man.

Cycloleucine (1-aminocyclopentanecarboxylic acid) administration in cancer patients resulted in a reversible marked aminoaciduria consisting predominantly of cystine, ornithine, lysine, and arginine, with only minor elevations of other amino acids. Plasma levels of amino acids were essentially unchanged except for slight decreases in ornithine and lysine. This aminoaciduria is most likely due to a blockage by the drug of the renal tubular reabsorption of cystine, ornithine, lysine, and arginine, resulting in an aminoaciduria of the type seen in cystinuria.

Amino Acids↗
PubMed1985

Asymptomatic low molecular weight proteinuria: a report on 5 cases.

In children with asymptomatic proteinuria, a high proportion of low molecular weight (LMW) proteins is an indicator of tubular malfunction. In a routine screening program covering the last 15 years and involving 280,000 children, aged between 3 and 19 years, we have identified 5 boys with LMW proteinuria. In 4 of these, renal biopsy was histologically normal on the first presentation. Follow-up for 4-16 years showed normal growth curves, but further evidence of tubular dysfunction appeared: glycosuria and hypophosphatemia in 2 patients; one of them had also aminoaciduria and rising serum creatinine (greater than 1.2 mg/100 ml). Another patient had only increased serum creatinine. The other two, still less than 13 years old, show so far no other abnormality than persistent LMW proteinuria. It is suggested that early identification of LMW proteinuria may presage gradual development of progressive tubular dysfunction with age and that such patients should be followed up indefinitely.

Adolescent↗
PubMed2004

Transient proximal renal tubular acidosis and Fanconi syndrome in a dog.

A 9-year-old spayed female Labrador Retriever was evaluated for anorexia, lethargy, and vomiting of 5 days' duration. Laboratory abnormalities included azotemia, high liver enzyme activities, hyperchloremic metabolic acidosis, glucosuria, ketonuria, proteinuria, and aminoaciduria. These laboratory abnormalities were diagnostic of proximal renal tubular acidosis and Fanconi syndrome. Results of initial and convalescent serologic tests for leptospirosis were negative. The dog was treated with amoxicillin, sodium bicarbonate, and potassium citrate at discharge. Repeated evaluations revealed resolution of the acidosis, azotemia, proteinuria, glucosuria, ketonuria, and high liver enzyme activities. Alkali administration was gradually discontinued, and the dog was clinically normal 8 months after discharge. The dog's clinical condition appeared to have been transient in nature, a phenomenon that is rarely seen in human or veterinary medicine.

Acidosis, Renal Tubular↗
PubMed1985

[Cortical renal microcysts in Lowe's syndrome].

We report a familial case of Lowe's syndrome with histological and ultrastructural examination of the renal biopsy. The patient was an eleven years old boy with operated congenital bilateral cataracts, mental and psychomotor retardation, hyperexcitability, muscular hypotonia, proteinuria, generalised aminoaciduria, proximal tubular acidosis and reduced glomerular filtrate. The renal biopsy showed, in addition to the alterations in the glomerular corpuscle (mesangial proliferation), proximal tubules (atrophy, dilatation, hyalinous or calcerous cylindres and mitochondrial abnormalities) and interstitium (fibrosis, lymphocytic infiltrate), large number of cortical microcysts, many of with corresponded to Bowman's cystic capsules with small glomeruloid projections.

Biopsy↗
PubMed1987

Increased urinary excretion of collagen metabolites in cadmium-metallothionein nephropathy.

In order to investigate the effect of cadmium-metallothionein (Cd-MT) on renal reabsorption of collagen metabolites, urinary excretion of hydroxylysine (Hyl), glucosyl-galactosyl-Hyl (Glc-Gal-Hyl), galactosyl-Hyl (Gal-Hyl), and hydroxyproline (Hyp), which are unique collagen metabolites, was determined in rats. Administration of Cd-MT resulted in acute renal failure in the form of proteinuria, aminoaciduria and glycosuria. Protein content in urine was greatly increased 1 day after injection of Cd-MT and decreased from 5 days, while the maximum levels of excretion of amino acids and glucose were observed at 6 days post-injection. The urinary excretion of total Hyp and Hyl, including Glc-Gal-Hyl, Gal-Hyl and free Hyl, were significantly increased at 3, 6 and 8 days after injection of Cd-MT with the maximum level at 6 days. Moreover, the molar ratio of Glc-Gal-Hyl/Gal-Hyl of urine in the Cd-MT-treated group was almost the same as that in the controls. These results suggest that a portion of Hyp, Hyl and its glycosides is normally reabsorbed from the renal tubule in the controls, and Cd-MT exposure caused an increase in urinary excretions of Hyp and Hyl, including its glycosides, through a renal tubular defect in reabsorption of Hyl in the same manner as with common amino acids.

Acute Kidney Injury↗
PubMed2006

VPS33B mutation with ichthyosis, cholestasis, and renal dysfunction but without arthrogryposis: incomplete ARC syndrome phenotype.

Arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome is a rare multisystem disorder first described in 1979 and recently ascribed to mutation in VPS33B, whose product acts in intracellular trafficking. Arthrogryposis, spillage of various substances in the urine, and conjugated hyperbilirubinemia define an ARC core phenotype, in some patients associated with ichthyosis, central nervous system malformation, deafness, and platelet abnormalities. We describe a patient with cholestasis, aminoaciduria, ichthyosis, partial callosal agenesis, and sensorineural deafness who, although homozygous for the novel VPS33B mutation 971delA/K324fs, predicted to abolish VPS33B function, did not exhibit arthrogryposis. The phenotypes associated with VPS33B mutation may include incomplete ARC.

Agenesis of Corpus Callosum↗
PubMed1998

Renal function in adult beta-thalassemia/Hb E disease.

Beta-Thalassemia hemoglobin E (beta-thal/Hb E) is the commonest form of hemoglobinopathy in Thailand. Shortened red cell life span, rapid iron turnover and tissue deposition of excess iron are major factors responsible for functional and physiological abnormalities found in various forms of thalassemia. Increased deposition of iron had been found in renal parenchyma of thalassemic patients, but no systematic study of the effect of the deposits on renal functions has been available. The purpose of this study is to describe the functional abnormalities of the kidney in patients with beta-thal/Hb E and provide evidence that increased oxidative stress might be one of the factors responsible for the damage. Urine and serum samples from 95 patients with beta-thal/Hb E were studied comparing with 27 age-matched healthy controls. No difference in the creatinine clearance was observed. beta-thal/Hb E patients excreted significantly more urinary protein (0.8+/-0.5 vs. 0.3+/-0.1 g/day, p < 0.001). Aminoaciduria was found in 16 % of the patients. Analysis of urinary protein by SDS-PAGE electrophoresis and silver staining revealed abnormal pattern of protein with increased small molecular weight (<45 kD) bands. Morning urine analysis showed significant lower urine osmolality (578.3+/-164.6 vs. 762.4+/-169.9 mosm/kg, p < 0.001) in patients. Patients excreted more NAG (N-acetyl beta-D-glucosaminidase, 26.3+/-41.3 vs. 8.4+/-3.9 U/g Cr, p < 0.0001) and beta2-microglobulin, 124.3+/-167 vs. 71+/-65.5 microg/g Cr, p = 0.001. Plasma and urine MDA (malonyldialdehyde) levels were both raised (p < 0.0001). Nine patients were selected for renal acidification study. All were found to be normal, but showed poor response to DDAVP challenge (urine osmolality 533+/-71). This is the first report of renal tubular defects found associated with beta-thal/Hb E disease. The mechanism leading to the damage is not known but it might be related to increased oxidative stress secondary to tissue deposition of iron, as indicated by the raised levels of serum and urine MDA. It is not known whether these functional defects would have any long-term effects on the patients. Further studies are warranted and means of prevention of these defects should urgently be sought.

Acetylglucosaminidase↗
PubMed2002

Hepatocyte nuclear factor 1 alpha controls renal expression of the Npt1-Npt4 anionic transporter locus.

Hepatocyte nuclear factor 1 alpha (HNF1alpha) is a transcription factor that is expressed in liver, pancreas, kidney and intestine. Mice lacking HNF1alpha are born normally but suffer from several defects including hyperphenylalaninemia, defective bile acid and cholesterol metabolism, an insulin secretion defect and renal Fanconi syndrome. The renal phenotype involves a defect in renal proximal tubule reabsorption, leading to polyuria, glucosuria, aminoaciduria and phosphaturia. We investigated the expression of genes encoding members of the sodium/phosphate cotransporter (Na(+)/Pi) family (namely Npt1, Npt2, Npt4 and Ram1). We show that Npt1 and Npt4 genes were expressed at reduced levels in the kidneys of HNF1alpha -/- mice, whereas the expression of Npt2, the major renal phosphate transporter, was not affected. Analysis of the Npt1 genomic sequence revealed the existence of several alternative promoters activated in liver and/or in kidney. All of these were down-regulated in the kidneys of HNF1alpha -/- animals. Several HNF1alpha binding sites (BS) play an important role in the transcriptional control of this locus, including low-affinity HNF1 BSs localised in a DNase I hypersensitivity site (HSS3). Transient transfection experiments confirmed that HNF1alpha directly transactivates the Npt1 promoter and that the HSS3 region contributes to this activation.

Animals↗
PubMed2003

Renal tubular dysfunction in alpha-thalassemia.

Shortened red cell life span and excess iron cause functional and physiological abnormalities in various organ systems in thalassemia patients. In an earlier study, we showed that beta-thalassemia patients have a high prevalence of renal tubular abnormalities. The severity correlated with the degree of anemia, being least severe in patients on hypertransfusion and iron chelation therapy, suggesting that the damage might be caused by the anemia and increased oxidation induced by excess iron deposits. This study was designed to define the renal abnormalities associated with alpha-thalassemia and to correlate the renal findings with clinical parameters. Thirty-four pediatric patients (mean age 8.2+/-2.8 years) with Hb H disease or Hb H/Hb CS were studied. Ten patients (group 1) were splenectomized, with a mean duration post splenectomy of 3.5+/-1.4 years; 24 patients (group 2) had intact spleens. The results were compared with 15 normal children. Significantly higher levels of urine N-acetyl-beta- d-glycosaminidase, malondialdehyde (MDA), and beta(2)-microglobulin were found in both groups compared with normal children. An elevated urine protein/creatinine ratio was recorded in 60% of group 1 and 29% of group 2. Two patients (5.9%), 1 in each group, had generalized aminoaciduria. We found proximal tubular abnormalities in alpha-thalassemia patients. Increased oxidative stress, possibly iron induced, may play an important role, since urine MDA levels were significantly increased in both groups of patients.

Acetylglucosaminidase↗
PubMed2003

[Chinese herbs-induced renal failure with Fanconi syndrome: a report of 6 cases].

OBJECTIVE: To understand the clinical and pathological features of patients with Fanconi syndrome associated with renal function damage induced by Chinese herbs. METHODS: Six cases with herb-induced renal failure associated with Fanconi syndrome were clinicopathologically analyzed. RESULTS: All six patients had kidney insufficiency after ingestion of Chinese herbs. All of them took the herbs containing aristolochia manshuriensis definitely. Four of the six presented with rapidly progressive acute renal failure and one with acute renal failure. All of them had similar clinical features, such as polydipsia, polyuria, anemia, glycosuria, aminoaciduria, increased urine beta(2) microglobin (beta(2)m) excretion and proximal tubular acidosis. Renal biopsies performed in 3 cases showed extensive hypocellular interstitial fibrosis, tubular atrophy and loss of tubules. Glomeruli were apparently intact. CONCLUSIONS: Nephropathy caused by Chinese herbs may be associated with Fanconi syndrome and renal failure.

Adult↗