title: Kidney stone inhibitors in patients with renal stones and endemic renal tubular acidosis in northeast Thailand.
abstract: Distal renal tubular acidosis (dRTA) is generally associated with hypercalciuria, hypocitraturia, and nephrolithiasis. Our intention was to study glycosaminoglycans (GAGS) and nephrocalcin (NC), two well-known crystal growth inhibitors, in a population with endemic dRTA and nephrolithiasis in northeast (NE) Thailand. We studied 13 patients, six with dRTA and seven with nephrolithiasis with normal or undefined acidification function. Six healthy adults living in the same area as the patients and another six from the Bangkok (BKK) area were used as controls. We measured urinary pH, ammonia, calcium, citrate, magnesium, oxalate, potassium, sodium and uric acid. GAGS were determined by an Alcian blue precipitation method and were qualitated by agarose gel electrophoresis after being isolated using 5% cetyltrimethylammonium bromide at pH 6.0. NC isoforms were isolated as previously described by Nakagawa et al. Citrate was higher in BKK controls ( p<0.04). There was a striking difference among GAGS from BKK when compared with other groups (103.85+/-10.70 vs. 23.52+/-8.11 for dRTA, 22.36+/-14.98 for kidney stone patients and 14.73+/-2.87 mg/ml in controls from the NE region, ( p<0.0001). dRTA and stone-forming patients excrete proportionally more (C+D) than (A+B) NC isoforms ( p<0.05). Also, their NC showed a 100-fold weaker binding capacity of calcium oxalate monohydrate crystals. The ratio of chondroitin sulfate/heparin sulfate in GAGS was approximately 9/1. In addition to the traditional risk factors for nephrolithiasis in dRTA, GAGS and NC might play an important role in the pathogenesis of stone formation in this population.
authors.affiliation: Kidney Stone Program, MC 5100, Division of Biological Sciences and the Pritzker School of Medicine, University of Chicago, 5841 S. Maryland Ave., Chicago, IL 60637, USA. ynakagaw@medicine.bsd.uchicago.edu
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nakagawa
authors.forename: Mauricio
authors.initials: M
authors.lastname: Carvalho
authors.forename: Prida
authors.initials: P
authors.lastname: Malasit
authors.forename: Sumalee
authors.initials: S
authors.lastname: Nimmannit
authors.forename: Suchai
authors.initials: S
authors.lastname: Sritippaywan
authors.forename: Somkiat
authors.initials: S
authors.lastname: Vasuvattakul
authors.forename: Somchai
authors.initials: S
authors.lastname: Chutipongtanate
authors.forename: Vipada
authors.initials: V
authors.lastname: Chaowagul
authors.forename: Sanga
authors.initials: S
authors.lastname: Nilwarangkur
mesh_terms: D000141:Acidosis, Renal Tubular / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology / Q000652:urine*; D000328:Adult; D002129:Calcium Oxalate / Q000037:antagonists & inhibitors; D005260:Female; D006023:Glycoproteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000652:urine; D006025:Glycosaminoglycans / Q000737:chemistry / Q000378:metabolism* / Q000652:urine; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007669:Kidney Calculi / Q000453:epidemiology* / Q000378:metabolism / Q000517:prevention & control*; D007686:Kidney Tubules, Distal / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012424:Rural Population; D013785:Thailand / Q000453:epidemiology; D014505:Urban Population
chemical_list: D006023:Glycoproteins; D006025:Glycosaminoglycans; C029490:nephrocalcin; D002129:Calcium Oxalate