Tamm-Horsfall Glycoprotein Excretion Research Articles

OIT3 deficiency impairs uric acid reabsorption in renal tubule

The oncoprotein induced transcript 3 (OIT3), also named liver-specific zona pellucida domain-containing protein (LZP), has been shown to be expressed in kidney, and was confirmed to interact with the Tamm–Horsfall glycoprotein (THP). However, the function of OIT3 in kidney remains unclear. In this study we found that serum uric acid level of Oit3 null mice was significantly lower than that in wild type controls, whereas the excretion of uric acid in urine increased in the mutant mouse. Significantly, the excretion of THP in urine also increased while renal THP decreased in Oit3 null mice. Our data suggest that OIT3 could maintain urate homeostasis by regulating the excretion and reabsorption of uric acid in renal tubule via cooperating with THP.

Tamm-Horsfall glycoprotein: biology and clinical relevance

Tamm-Horsfall glycoprotein (THP) is the most abundant urinary protein in mammals. Urinary excretion occurs by proteolytic cleavage of the large ectodomain of the glycosyl phosphatidylinositol-anchored counterpart exposed at the luminal cell surface of the thick ascending limb of Henle's loop. We describe the physical-chemical structure of human THP and its biosynthesis and interaction with other proteins and leukocytes. The clinical relevance of THP reported here includes: (1) involvement in the pathogenesis of cast nephropathy, urolithiasis, and tubulointerstitial nephritis; (2) abnormalities in urinary excretion in renal diseases; and (3) the recent finding that familial juvenile hyperuricemic nephropathy and autosomal dominant medullary cystic kidney disease 2 arise from mutations of the THP gene. We critically examine the literature on the physiological role and mechanism(s) that promote urinary excretion of THP. Some lines of research deal with the in vitro immunoregulatory activity of THP, termed uromodulin when isolated from urine of pregnant women. However, an immunoregulatory function in vivo has not yet been established. In the most recent literature, there is renewed interest in the capacity of urinary THP to compete efficiently with urothelial cell receptors, such as uroplakins, in adhering to type 1 fimbriated Escherichia coli. This property supports the notion that abundant THP excretion in urine is promoted in the host by selective pressure to obtain an efficient defense against urinary tract infections caused by uropathogenic bacteria.

Decreased Renal Expression of the Putative Calcium Oxalate Inhibitor Tamm-Horsfall Protein in the Ethylene Glycol Rat Model of Calcium Oxalate Urolithiasis.

Tamm-Horsfall protein is believed to inhibit calcium oxalate crystallization, aggregation or adhesion to the renal epithelium. We determined whether ethylene glycol induced urolithiasis changes the expression of renal and urinary Tamm-Horsfall protein. For comparison the expression of another calcium oxalate inhibitor, osteopontin, was also analyzed. Male rats were treated with 0.75% ethylene glycol plus an AIN-76 diet (Dyets, Bethlehem Pennsylvania) (ethylene glycol group) or standard rat chow and water (control group) for up to 8 weeks (6 per group for 8 weeks and 3 per group for 3 days to 6 weeks). Kidneys and urine (8 weeks only) were harvested and analyzed by Northern and Western blot analysis, and immunohistochemistry. Tamm-Horsfall protein message and protein (membrane bound form) were decreased, while those of osteopontin were increased in the kidneys of rats treated with ethylene glycol for 8 weeks. As judged by immunochemistry Tamm-Horsfall protein and osteopontin were consistently present in a few tubules in rats in the ethylene glycol and control groups, respectively. In urine expression of the free form of Tamm-Horsfall protein (approximately 75 kDa.) was decreased but detectable in ethylene glycol treated rats. Although readily detected in tissue, osteopontin was not detected in the urine of control or ethylene glycol treated rats. In the time course experiment Tamm-Horsfall protein did not decrease until 4 weeks, when calcium oxalate crystals were detectable in the kidneys of treated rats. In contrast, osteopontin was increased, although inconsistently, beginning at 3 days. Unlike other calcium oxalate inhibitors, such as osteopontin, renal message and protein for Tamm-Horsfall protein was decreased in ethylene glycol treated rats. Tamm-Horsfall protein expression did not decrease until aggregates of crystals had been deposited in the kidneys, while osteopontin expression began to increase almost immediately. Comparisons of the data on kidneys and urine obtained by RNA or protein blot analysis and immunochemistry underscore the need to examine tissue and urine by multiple techniques to obtain the most accurate assessment of how protein expression is changed by a given treatment.

Increased Excretions of β2-Microglobulin, IL-6, and IL-8 and Decreased Excretion of Tamm-Horsfall Glycoprotein in Urine of Patients with Active Lupus nephritis

Tubulointerstitial nephritis is a less frequently recognized but important complication of systemic lupus erythematosus. We have investigated the cytokine β₂-microglobulin (β₂M) and Tamm-Horsfall glycoprotein (THG) excretions in the urine of systemic lupus erythematosus patients to identify indices for evaluation of tubulointerstitial inflammation in lupus nephritis (LN). Daily urine was collected from 15 patients with active LN, from 12 patients with inactive LN, and from 17 normal subjects. The amounts of soluble interleukin (IL) 2 receptor, IL-6, IL-8, β₂M, and THG in urine were measured. β₂M and THG were regarded as indicators of proximal and distal renal tubule function, respectively. The urinary excretions of IL-6 and IL-8 were significantly higher in patients with active LN than in those with inactive LN and in normal individuals. The excretion of soluble IL-2 receptor in all three groups of subjects was not significantly different. On the other hand, the excretion of β₂M in patients with LN was significantly higher than that in normal individuals. The excretion of β₂M in patients with active or inactive LN was not significantly different. The THG excretion was lower in patients with active LN and tubulointerstitial inflammation as compared with patients with inactive LN or normal individuals. Six patients underwent pulse cyclophosphamide therapy during the course of experiments. Five of them showed a decrease in IL-8 and IL-6 excretions in urine after the treatment. The excretions of β₂M and THG in urine, in addition to IL-6 and IL-8, can reflect the renal inflammatory activity in patients with lupus tubulointerstitial nephritis as well as in those having lupus glomerulonephritis.

Decreased Tamm-Horsfall Protein in Lithiasic Patients

Abstract Objectives: Tamm-Horsfall glycoprotein (THP) is the most abundant substance of renal origin appearing in urine. It seems to be one of the major inhibitors of calcium oxalate crystal nucleation and/or aggregation, but its role in the pathogenesis of stone formation has not yet been clarified. The present work was undertaken to quantify THP excretion in lithiasic (L) patients, so as to deterline if these levels are different from those of control subjects (C). Design and Methods: THP was isolated from human urine by reprecipitation steps, rabbit antiTHP antibody was obtained and its specificity determined, an ELISA was developed and technical conditions standardized, and quantitative measurements of urinary THP were performed on samples from L patients, who had suffered more than one lithiasic episode, and from C subjects. Microtiter plates coated with THP or diluted urine samples were subjected to successive incubation with antiTHP and alkaline phosphatase antirabbit IgP. Results: A good correlation between measured absorbance and THP concentration in standard and urine samples was observed. Data, expressed as Median and Interquartile Range, are 388/209–626 μg THP/mmol creatinine for C ( n = 85) and 124/82–171 μg THP/mmol creatinine for L ( n = 23). Conclusions: We have obtained an antiserum antiTHP that can be used in the ELISA technique to determine reliable urinary THP values. The results show a significant decrease of THP excretion in recurrent stone formers compared to controls ( p

Decreased Tamm-Horsfall protein in lithiasic patients

Objectives: Tamm-Horsfall glycoprotein (THP) is the most abundant substance of renal origin appearing in urine. It seems to be one of the major inhibitors of calcium oxalate crystal nucleation and/or aggregation, but its role in the pathogenesis of stone formation has not yet been clarified. The present work was undertaken to quantify THP excretion in lithiasic (L) patients, so as to deterline if these levels are different from those of control subjects (C). Design and Methods: THP was isolated from human urine by reprecipitation steps, rabbit antiTHP antibody was obtained and its specificity determined, an ELISA was developed and technical conditions standardized, and quantitative measurements of urinary THP were performed on samples from L patients, who had suffered more than one lithiasic episode, and from C subjects. Microtiter plates coated with THP or diluted urine samples were subjected to successive incubation with antiTHP and alkaline phosphatase antirabbit IgP. Results: A good correlation between measured absorbance and THP concentration in standard and urine samples was observed. Data, expressed as Median and Interquartile Range, are 388/209–626 μg THP/mmol creatinine for C ( n = 85) and 124/82–171 μg THP/mmol creatinine for L ( n = 23). Conclusions: We have obtained an antiserum antiTHP that can be used in the ELISA technique to determine reliable urinary THP values. The results show a significant decrease of THP excretion in recurrent stone formers compared to controls ( p < 0.001) and may have interesting implications in the pathogenesis of urolithiasis.

The relationship between urinary Tamm-Horsfall glycoprotein excretion and urinary activity of glycosidases in normal pregnancy and pre-eclampsia

Electrophoretic analyses of the urinary proteins of pre-eclamptic patients revealed a decrease in the staining intensity of the protein band representing the Tamm-Horsfall glycoprotein (THP). In the present study the quantitative analysis of the THP excretion rate and the urinary activity of THP oligosaccharide metabolizing glycosidases were investigated. The median THP excretion rate of non-pregnant women ( n = 24) was 20 mg/g creatinine (crea.). An increase in the THP excretion rate was seen in pregnancy to a level between 43 mg/g crea. (II. trimester) and 32 mg/g crea. (III. trimester) ( n = 29). Hypertension in pregnancy was associated with a decrease in the THP excretion rate to 9 mg/g crea. ( n = 85). Post partum, a transient elevated THP excretion rate up to 109 mg/g crea was recorded in the group of hypertensive patients. The urinary activities of the lysosomal β-mannosidase, α-fucosidase, α-mannosidase (pH 4.5) and β-galactosidase increased in normal pregnancy. This effect was most pronounced in the β-galactosidase activity which increased from 50 U/mg crea. before pregnancy to 280 U/mg crea. at term. Hypertension in pregnancy was associated with a further increase in the activities of the lysosomal glycosidases. In the case of the β-galactosidase a significant rise from 68 to 310 U/mg crea. was found. The urinary activity of the α-mannosidase (pH 5.5) originating from the Golgi apparatus was only elevated in patients with severe pre-eclampsia. Casuistic post partum recordings demonstrated that an elevation of the lysosomal glycosidases activities was followed by a transient increase in the THP excretion rate.

Excretion of urinary Tamm-Horsfall glycoprotein in girls with recurrent urinary tract infections.

Tamm-Horsfall glycoprotein (THG) might constitute a bacteria-fixing mucus which contributes to the non-immunological anti-infectious mechanisms of the lower urinary tract. To evaluate the role of THG in girls with idiopathic recurrent lower urinary tract infections, the THG excretion and concentration in 24-h urine were measured by a radial immunodiffusion method in 16 patients with a median age of 9 years and in 14 healthy age-matched girls. The results showed no significant differences in the THG excretion or concentration between the patients and the controls. Transiently decreased THG excretion rates as well as functional changes in the ability and/or capacity to trap bacteria, however, may leave girls periodically prone to colonization of the bladder. Thus, further studies are warranted to evaluate the importance of THG in the bladder defence mechanism.

Human Tamm-Horsfall glycoprotein: urinary and plasma levels in normal subjects and patients with renal disease determined by a fully validated radioimmunoassay.

A recently developed, simple and sensitive radioimmunoassay has been used to examine 24 h excretion and plasma levels of Tamm-Horsfall glycoprotein (THG) in normal subjects, stone formers and patients with stable chronic renal disease. In normal subjects THG excretion ranged from 22 to 66 mg/24 h, with no sex difference and no correlation with creatinine clearance or body surface area. There was no correlation between 24 h THG excretion and urine volume, pH or osmolality, excretion of Na+, K+ or Ca2+ or free-water clearance. There was a small significant correlation between plasma THG concentration and urinary THG excretion. A good correlation was obtained between the THG/creatinine ratio in 24 h and random samples. This made possible the use of random samples to establish a reference range for THG excretion of 0.15-0.50 micrograms/ml of creatinine clearance which did not depend on sex or age. The excretion rate of THG in stone formers was generally within the reference range. It was not significantly different in those who were hypercalciuric or in those taking thiazides. In patients with chronic renal disease there was a good correlation between 24 h THG excretion, plasma THG concentration and creatinine clearance. The range of excretion of THG per ml of creatinine clearance was greater than in normal subjects, independent of the type of renal disease and unrelated to proteinuria. In patients with glomerulonephritis the excretion of THG per ml of creatinine clearance was significantly higher in those with well-preserved tubules compared with those with tubular atrophy.

Tamm-Horsfall glycoprotein excretion and aggregation during intravenous urography. Relevance to acute renal failure.

The effect of intravenous urography (IVU) on the excretion rate and precipitation of Tamm-Horsfall glycoprotein (THG) has been evaluated in 19 patients. Urine samples were collected immediately before the administration of contrast medium (U1) and then during the period of the excretion urogram (U2). The urinary THG: creatinine clearance ratio decreased in 15 patients by a mean of 28.2% (range 2.9-70.8) and increased in four by a mean of 22.8% (range 13.5-36.4). In 18 of 19 patients the amount of THG precipitated following the IVU decreased from an average of 75.6% of the total in U1 (range 2.2-100) to 19.5% (range 2.0-59) in U2. In the one exception the fraction precipitated was only 2.2% in U1 and 2.5% in U2. It is concluded that during routine IVU there is no marked increase in the excretion rate of THG. More importantly, the percentage of THG precipitated actually decreases.

Radioimmunoassay for serum and urinary Tamm-Horsfall glycoprotein in the rat.

Rat Tamm-Horsfall glycoprotein (THG) was isolated from urine and disaggregated by gel filtration. Purity was confirmed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and autoradiography. Antibodies were raised and used in the development of a specific radioimmunoassay for rat THG. Parallelism could be demonstrated between the standard preparation and urine (diluted to 1:320 with distilled water) and serum (at all dilutions) samples. Recovery of standard added to urine or serum was on average 93% and inter- and intra-assay variation were both below 7%. There was a positive correlation between the mean urinary excretory rate of THG (microgram/24h) and body weight in female rats (p less than 0.001) but not in male rats. Serum THG levels were similar in both sexes and showed a positive correlation with body weight (p less than 0.001; range 43-240 ng/ml). It is concluded that the rat urinary THG excretion rate is similar to that in man and that rat serum also contains a THG-like protein.