Oral L-arginine supplementation ameliorates urinary risk factors and kinetic modulation of Tamm-Horsfall glycoprotein in experimental hyperoxaluric rats.

BACKGROUND: Oral supplementation of l-arginine (l-arg) is found to be beneficial in many kidney disorders. We determined whether l-arg supplementation safeguards the renal epithelial cell damage induced by hyperoxaluria with excretion of urinary marker enzymes and lithogenic salts with special reference to Tamm-Horsfall glycoprotein (THP). METHODS: Hyperoxaluria was induced by 0.75% ethylene glycol (EG) in drinking water. l-Arg was co-supplemented at the dose of 1.25 g/kg b.w. orally for 28 days. At the end of experimental period, 24-h urine samples were collected in all the experimental groups. Isolation and purification of THP was carried in rat urine and were subjected to spectrophotometric crystallization assay and calcium-(14)C-oxalate binding studies. Determination of the lithogenic risk factors like calcium, oxalate, phosphorus, citrate, and marker enzymes such as lactate dehydrogenase (LDH) and gamma-glutamyltransferase (gamma-GT) were carried out in the collected urine sample. RESULTS: Urinary excretion of calcium and oxalate was significantly increased in EG-treated rats. In l-arg supplemented hyperoxaluric rats, these concentrations were significantly (p<0.001) decreased when compared to that of hyperoxaluric rats, and were moderately elevated from that of control rats. The activities of urinary marker enzymes, both LDH and gamma-GT were 2-fold increased in EG-treated rats, when compared to control rats, but these values were maintained near normal in l-arg supplemented EG-treated rats. Citrate excretion was enhanced in the l-arg co-supplemented hyperoxaluric rats. In spectrophotometric crystallization assay system, l-arg supplemented rat THP showed inhibition in nucleation and aggregation phases, whereas EG-treated rat THP showed promotion of both calcium oxalate nucleation and aggregation phases. In calcium-(14)C-oxalate binding assay, THP derived from hyperoxaluric rats exhibited 2-fold increase (p<0.001) in the Ca*Ox binding when compared to control and l-arg supplemented animals. CONCLUSIONS: l-Arg could act as a potent antilithic agent, by increasing the level of citrate in the hyperoxaluria-induced rats and decreasing calcium oxalate binding to the THP. l-Arg also effectively prevents the deposition of calcium oxalate crystals by curtailing the renal epithelial damage and protein oxidation as evidenced by the normal activities of urinary marker enzymes in l-arg supplemented hyperoxaluric rats.

Effects of Tamm-Horsfall protein and albumin on the inhibition of free radicals.

INTRODUCTION: Oxalate in urine can cause tubular cellular damage by the production of free radicals. Then, cell death and cellular debris may promote the retention of calcium oxalate crystals and finally the formation of stones. The two most abundant urinary proteins, Tamm-Horsfall protein (THP) and albumin, were tested for the effects of antioxidants. MATERIALS AND METHODS: By using xanthine-xanthine oxidase reaction, purified THP and albumin were tested for the inhibitory effect. OD(295) was used as a spectrophotometric method to measure the production of uric acid during the reaction. RESULTS AND CONCLUSIONS: Both proteins can inhibit the reaction of xanthine oxidase on xanthine, although the effect was decreased after enzymatic deglycosylation of sialic acid. Albumin has an IC(50) of 10.7 nM in native condition and 11.9 nM after deglycosylation, whereas THP has 69.6 nM in native condition and 102.0 nM in deglycosylated condition. The data indicates that THP and albumin have an antioxidant effect. Sialic acid in THP has partly an inhibitory effect and is associated with calcium oxalate formation. Studies have indicated that further investigation of the role of free radicals in the formation of urolithiasis and of sialic acid in protein function is needed.

Urothelial cytoprotective activity of Tamm-Horsfall protein isolated from the urine of healthy subjects and patients with interstitial cystitis.

PURPOSE: Tamm-Horsfall protein (THP) is a ubiquitous urinary protein with essentially no known function. We propose that THP is a cytoprotective agent that protects the urothelium from cationic species. To test this hypothesis we isolated THP from normal and interstitial cystitis urine to see if it could protect cultured cells from damage induced by the polyamine, protamine sulfate (PS). METHODS: Tamm-Horsfall protein was extracted from the urine of interstitial cystitis (IC) patients (N=28) and normal volunteers (N=5). Urothelial target cells (T24) were radiolabeled with 51Cr and then exposed to PS (0-1.0 mg/mL) for either 1.5 or 20 h. The resulting cytotoxicity data (dose-response curves) were then compared with the data obtained when PS was preincubated with 0-0.5 mg/mL of THP (IC vs normal), the semisynthetic polysaccharide, pentosan polysulfate (Elmiron), or human serum albumin. RESULTS: Toxicity of PS was significantly reduced by incubation with THP (or Elmiron) prior to evaluation by the chromium release assay, but not reduced by incubating with another protein, albumin. Tamm-Horsfall protein from IC patients' urine was less protective than an equal quantity of THP from normal urine. CONCLUSIONS: These experiments suggest that THP has an important role in bladder mucosal defense mechanisms, protecting the bladder surface from injury. Inability of THP to prevent cytotoxic damage by urinary polyamine or other urinary toxins (cationic species) may be relevant in the etiology of interstitial cystitis, as putative urinary toxic components have been described in the urine of some patients.

[Relationship between Syndrome-Type in TCM and four trace urinary proteins in patients with bronchial asthma].

OBJECTIVE: To explore the possible relationship between Syndrome-Type in TCM and the 4 trace urinary proteins in patients with bronchial asthma. METHODS: The 4 kinds of trace urinary proteins in 217 patients with asthma were measured by radioimmunoassay, and that in 66 normal subjects were compared. RESULTS: The results showed that there were increments of urinary albumin, urinary IgG, urinary beta 2-microglobulin and urinary Tamm-Horsfall protein in patients with asthma; and the gradual increase tended to be accompanied by the continuous aggravation of patient's condition on TCM Syndrome-Type. Furthermore, these datas proved that the 4 trace urinary proteins might be the most sensitive indicators for detecting impaired renal functions than serum blood urea nitrogen and creatinine. CONCLUSIONS: There were the objective material foundations on TCM Syndrome-Type in asthmatics, which consisted of renal glomerular dysfunctions to filter out albumin and IgG, renal tubular dysfunction to reabsorb beta 2-microglobulin, and to synthesize and excrete Tamm-Horsfall protein.

Patients with recurrent renal stones have a physico-chemically altered urinary Tamm-Horsfall glycoprotein profile.

We describe an immunoblotting method for examining the electrophoretic properties of urinary Tamm-Horsfall protein. Using this method we tested frozen urine samples from a group of 37 thoroughly investigated recurrent idiopathic renal calcium stone formers and compared this with fresh urine from 19 non-stone forming laboratory staff. We found that there was a statistically significant different pattern of Tamm-Horsfall protein bands in the two sets of urines, with stone formers tending to have two bands and non-stone formers tending to have three bands. This could have been due to storage artefact and therefore a further group of 13 fresh urines from unselected renal stone formers was tested. A smaller proportion of these cases showed the two-band pattern, possibly because not all of this group were idiopathic calcium stone formers. This suggests that but does not prove that there is no significant storage artefact and that there may be an in vivo effect causing stone formation.

Isoelectric focusing of Tamm-Horsfall glycoproteins: a simple tool for recognizing recurrent calcium oxalate renal stone formers.

Tamm-Horsfall glycoproteins (THPs) from healthy probands and a majority of recurrent calcium oxalate renal stone formers reveal different physicochemical properties when analyzed using isoelectric focusing (IEF). The pI values of THPs from healthy probands are approximately 3.5 while THPs from recurrent renal stone formers have pI values of between 4.5 and 6. The two groups of THPs exhibit completely different protein patterns. The differences in IEF analysis allow differentiation between THPs from healthy probands and recurrent calcium oxalate stone formers and may possibly be used as a simple diagnostic method for the recognition of recurrent calcium oxalate renal stone formers.

Nucleotide sequence and peptide motifs of mouse uromodulin (Tamm-Horsfall protein)--the most abundant protein in mammalian urine.

The mouse uromodulin cDNA sequence was sequenced. The predicted peptide sequence is 642 amino acids long and contains several modular components including four epidermal growth factor like repeats, one betaglycan-like domain (ZP domain), and a consensus sequence for attachment of a glycosyl-phosphatidyl-inositol anchor. An arginine-glycine-aspartate tripeptide reported for rat and human sequence is absent in the mouse. There are several potential sites for post-translational modification.

Limitation of shock-wave-induced renal tubular dysfunction by nifedipine.

In a prospective randomized study, the effects of the calcium entry blocker nifedipine on shock-wave-induced tubular impairment were studied. 24 patients with renal pelvic or calyceal stones undergoing anesthesia-free extra-corporeal shock wave lithotripsy (ESWL) without ancillary measures were randomly assigned to the nifedipine group (n = 12) or the control group (n = 12). Four doses of nifedipine (10 mg t.i.d.) were given orally, starting the night before ESWL. Controls received no medication. To assess renal tubular function, the urinary excretion of alpha 1-microglobulin (A1M), N-acetyl-beta-glucosaminidase (NAG) and Tamm-Horsfall protein (THP) were measured before, immediately, 12 and 24 h after ESWL. After lithotripsy, there was a rise in urinary A1M and NAG which was significantly higher in the control than in the nifedipine group. THP, a glycoprotein synthesized by distal tubular cells, fell significantly less in the nifedipine group compared to the controls. Our results indicate that nifedipine exhibits a protective effect on shock-wave-induced tubular damage similar to verapamil. The underlying mechanisms are not clarified yet, direct actions on tubular cells and interference with renal hemodynamics have to be discussed.

Ascorbic acid is an abettor in calcium urolithiasis: an experimental study.

Two sets of animal experiments using guinea pigs were planned to evaluate the effect of ascorbic acid supplementation on the lithogenic process. In the first set of experiments, 10, 40, and 60 mg doses of ascorbic acid/100g body weight/day were given for 105 days. Neither of the ascorbic acid doses given induced crystalluria, calcification or stone formation, thereby confirming our previous findings that ascorbic acid in the doses used by clinicians does not cause urolith formation. In the second set of experiments, ascorbic acid was supplemented in hypercalciuric (induced by calcium carbonate feeding) and hyperoxaluric (induced by sodium oxalate feeding) animals for 45 days. The results indicated that it exacerbated the calcification process in renal and bladder tissue.

[Effects of furosemide, propranolol and nifedipine on urinary excretion of Tamm-Horsfall protein in patients with arterial hypertension]. / Wplyw furosemidu, propranololu i nifedypiny na wydalanie bialka Tamma-Horsfalla z moczem u chorych na nadcisnienie tetnicze.

UNLABELLED: In 65 hypertensive patients the influence of 10 day treatment with furosemide (24 subjects), nifedipine (21 subjects) and propranolol (20 subjects) respectively on urinary Tamm-Horsfall protein (U-THP), sodium and potassium excretion, 24 hour urinary volume and blood pressure was determined. In 23 control subjects the above mentioned parameters were assessed only under basal conditions. In hypertensive patients urinary THP excretion was not different from controls. In all examined groups a significant positive correlation was found between urine volume and urinary THP excretion under basal conditions. Such a correlation was absent after nifedipine or propranolol therapy respectively, but still existed after furosemide administration. No correlation was found between urinary THP and Na and K excretion respectively. In contrast to nifedipine and propranolol, a 10 day treatment with furosemide caused a significant increase in U-THP. CONCLUSIONS: Urinary THP excretion in hypertensive patients did not differ from U-THP in healthy subjects. In contrast to propranolol and nifedipine, treatment with furosemide caused an increase in THP urinary excretion.

Urinary biochemical profile of patients with ureteric calculi in Jodhpur region (north western India).

Urine chemistry of 42 normal subjects (NS) and 59 ureteric stone formers (SF) from Jodhpur region of Rajasthan, India is presented. Twenty four hour urinary levels of calcium, oxalic acid and uromucoids were significantly higher and levels of magnesium, citric acid and inorganic phosphorus were significantly lower in SF as compared to NS. No significant difference was observed in the uric acid, sodium and potassium levels in the two groups. Significant correlation was observed between calcium and magnesium; calcium and oxalic acid; calcium and citric acid; magnesium and oxalic acid; and oxalic acid and citric acid in NS on the basis of mmol/l but not on the basis of mmol/24 h. Calcium and oxalic acid correlation was uninfluenced by magnesium and citric acid levels. The log of risk factor index (RI) was higher (p less than 0.001) in SF (-1.652) as compared to NS (-2.103). The log of ion activity product (IAP) was also higher (p less than 0.001) in SF (-3.192 X 10(-3)) than in NS (-2.914 X 10(-1)). Based on RI and IAP, a scale has been devised for the prediction of the risk of stone formation and recurrence.

Hormonal and cardiac response of autistic children to changes in environmental stimulation.

A study was made of physiological responses of autistic children to variations in environmental load in order to examine the under- versus over-arousal dichotomy. More specifically, measures of urinary mucoprotein excretion and mean heart rate and three measures of heart rate variability were compared with matched controls in conditions of normal, high, and low total environmental load. The results suggest that, although behaviorally unresponsive, the autistic children responded physiologically, were generally in a lower state of arousal than the control group, and were labile in response to changes in stimulation.