Normal Human Ureter Research Articles

The role of HCN channels in peristaltic dysfunction in human ureteral tuberculosis

ObjectiveTo explore the role of HCN channels in ureteral peristaltic dysfunction by comparing the changes in HCN channel levels between normal and tuberculous ureters.MethodsA total of 32 specimens of human upper ureters were collected by nephrectomy from patients with renal tumor (control group, n = 16) or from patients with renal tuberculosis (experimental group, n = 16); the two groups did not receive radiotherapy, chemotherapy, immunotherapy, or any other special treatment before the surgical procedure. An experimental study on smooth muscle strips of human upper ureters showed variation in contraction amplitude and frequency after adding ZD7288, a specific blocker of HCN channels. The expression of HCN channels in the ureter was confirmed by Western blot (WB) and by confocal analysis of double immunostaining for c-kit and HCN channel proteins.ResultsBefore the addition of ZD7288, the experimental and control groups showed significant differences in the frequency and amplitude of the spontaneous contraction of isolated ureteral smooth muscle strips. After ZD7288 was added, the frequency and amplitude of the contractions of the ureteral smooth muscle strips were significantly lower in both groups. The differences observed before and after ZD7288 treatment in each group were significant (P < 0.001), and the difference in contraction amplitude observed between the two groups before ZD7288 was also significantly different (P < 0.001). By using WB technology, we showed that the expression of HCN channels was present in normal human ureters, with the expression of HCN4 and HCN1 being the highest; the expression of HCN4 and HCN1 in the control and experimental groups were both statistically significant (P < 0.001). HCN4 and HCN1 were expressed in the mucosal and smooth muscle layers of human control ureters and tuberculous ureters, as revealed by a confocal analysis of double immunostaining for c-kit and HCNs proteins; there were significant differences between the two groups (P < 0.001).ConclusionFour HCN channels are expressed in the ureter, mainly HCN4 and HCN1, suggesting that HCN channels are involved in the peristaltic contraction of ureteral ICCs, which may be an important reason for peristaltic dysfunction in ureteric tuberculosis.

Urothelial Cell Platelet-activating Factor Production Mediated by Calcium-independent Phospholipase A 2γ

To determine the effect of phospholipase A(2) (PLA(2)) inhibitors on urothelial cell platelet-activating factor (PAF) production in response to tryptase stimulation. Urothelial cells isolated from normal human ureters were immortalized with the human papillomavirus type 16E6E7 cell line (TEU-2 cells). PLA(2) activity in TEU-2 cells was measured using (16:0, [(3)H]18:1) plasmenylcholine and phosphatidylcholine substrates in the presence and absence of calcium. [(3)H]PAF production was measured in TEU-2 cells prelabeled with [(3)H] acetic acid. PAF-acetylhydrolase activity was measured by determining the amount of [(3)H] acetate hydrolyzed from [(3)H]PAF incubated with TEU-2 cellular protein. Adherence of human polymorphonuclear leukocyte (PMN) to TEU-2 cells was assessed by measuring myeloperoxidase activity in adherent PMNs after incubation with TEU-2 cells. Most PLA(2) activity measured in TEU-2 cells was determined to be membrane-associated, calcium-independent PLA(2) and selective for plasmenylcholine substrate. Stimulation of TEU-2 cells with tryptase results in increased production of PAF and increased PMN adherence that were inhibited completely by pretreatment with the membrane-associated, calcium-independent PLA(2)γ-selective inhibitor (R)-bromoenol lactone. Pretreatment with the cytosolic PLA(2) inhibitor methyl arachidonyl fluorophosphonate resulted in potentiation of tryptase-stimulated PAF production and PMN adherence to TEU-2 cells that is a result of PAF-acetylhydrolase inhibition. Tryptase stimulation of TEU-2 cells results in activation of membrane-associated, calcium-independent PLA(2)γ, leading to an increase in PAF production and increased PMN adherence. Inhibition of TEU-2 cell PAF-acetylhydrolase activity with methyl arachidonyl fluorophosphonate potentiated tryptase-stimulated PAF production and PMN adherence.

The Protective Role of Renal Parenchyma as a Barrier to Local Tumor Spread of Upper Tract Transitional Cell Carcinoma and its Impact on Patient Survival

We investigated whether tumor location has independent prognostic significance in upper tract transitional cell carcinoma cases and which factor determines it. We reviewed data on 122 renal pelvis and 102 ureteral tumor cases, including the recurrence pattern. Tumor location and other clinicopathological variables were evaluated regarding cancer specific and recurrence-free survival. Stage pT3 tumors were stratified into those invading renal parenchyma or peripelvic/periureteral fat. Overall 5-year cancer specific survival and recurrence-free survival rates were 77.0% and 71.6%, respectively, at a mean followup of 60.7 months. Of the clinicopathological parameters T stage was the most significant prognosticator of the survival rate, while nodal involvement, high grade and ureteral tumor location were also significant for lower survival rates. Stratification analysis for matching pathological stage revealed that, while survival rates were similar in the renal pelvis and ureteral tumor groups at stage pT2 or less, renal pelvic tumors were associated with significantly higher survival rates than ureteral tumors for stage pT3. Specifically renal pelvic tumors invading the renal parenchyma were associated with a lower local failure rate, and higher cancer specific and recurrence-free survival rates than tumors invading peripelvic or periureteral fat, ie 77.5% vs 49.7% 5-year cancer specific survival and 75.6% vs 32.0% 5-year recurrence-free survival (p = 0.014 and 0.003, respectively). Tumor location is an independent prognostic factor for pT3 upper tract transitional cell carcinoma. The overall better prognosis of renal pelvic tumors was mainly attributable to pT3 tumor outcomes, specifically lesions invading the renal parenchyma. These findings may be due to the protective role of thick renal parenchyma against local tumor spread.

Characterization of stratification and tight junction formation in cultured human urothelial cells

The urothelium is composed of stratified transitional epithelium of 3 cell types: basal, intermediate, and superficial. It has been proposed that urothelial cells acquire their mature characteristics through differentiation. The most differentiated, superficial cells develop tight junctions (TJs) that restrict urine movement and abnormalities in barrier function may be involved in syndromes such as interstitial cystitis. To further our understanding of urothelial differentiation, we used cells from normal human ureter and examined the zonula occludens (ZOs), “undercoat” scaffolding proteins in the cytosol that interact with claudins and actin filaments. Cell monolayers were stratified and differentiated using Ca and fetal bovine serum (FBS) and the process was studied using impedance, videomicroscopy, and confocal immunohistochemistry. With addition of Ca and FBS, impedance quickly increased by 2.5 fold. Withdrawal of the supplements returned impedance to baseline, suggesting the formation of tight junctions, rather than increased cell proliferation and immunohistochemistry demonstrated the appearance of ZO‐1 at cell junctions minutes after supplement addition. Observation by videomicroscopy suggested that cell division continued to occur after the cells had differentiated. Taken together, these studies increase our understanding of urothelial development.Supported by DK66119 (JM)

Obstruction Alters the Effect of Prostaglandin E2 on Ureteral Contractility

Although our understanding of ureteral physiology during acute obstruction remains limited, we believe that prostanoids (prostaglandins [PGs], thromboxanes, prostacyclins) play a major role in modulation of ureteral contractility and that inhibition of prostanoid synthesis causes substantial reduction in in-vitro and in-vivo ureteral contractility rates. The purpose of this study was to determine the in-vitro effects of PGE2 on chronically obstructed human and acutely obstructed porcine ureters. Female pigs underwent unilateral laparoscopic ureteral obstruction. Following 1, 2, 6, 24, and 48 hours of obstruction (n = 3 at all points), animals were euthanized, and obstructed, contralateral nonobstructed, and normal (from unobstructed pigs) ureters were harvested. Chronically obstructed human ureter was obtained from subjects who underwent nephrectomy to remove nonfunctioning kidneys. Normal human ureter was obtained from the discarded portion of excess distal ureter in patients undergoing elective donor nephrectomy. Rings 4 to 5 mm long were suspended in aerated Krebs buffer, and their spontaneous contractions and contraction in response to various concentrations of PGE2 were recorded. Prostaglandin E2 increased contractility in chronically obstructed human ureters. In acutely obstructed porcine ureteral segments, low concentrations of PGE2 inhibited ureteral contractility in a dose-dependent fashion, similar to controls. At higher concentrations of PGE2, contractility was increased. This increase was more pronounced with longer intervals of obstruction in a time-dependent manner. Prostaglandin E2 increased contractility in obstructed ureters while relaxing normal and nonobstructed ureters. The response to PGE2 was accentuated by a longer duration of obstruction. Prostaglandin E2 may be a unique target for pharmacologic modulation in the treatment of symptoms associated with acute urinary obstruction.

Urothelial umbrella cells of human ureter are heterogeneous with respect to their uroplakin composition: different degrees of urothelial maturity in ureter and bladder?

Urothelial umbrella cells are characterized by apical, rigid membrane plaques, which contain four major uroplakin proteins (UP Ia, Ib, II and III) forming UPIa/UPII and UPIb/UPIII pairs. These integral membrane proteins are thought to play an important role in maintaining the physical integrity and the permeability barrier function of the urothelium. We asked whether the four uroplakins always coexpress in the entire human lower urinary tract. We stained immunohistochemically (ABC-peroxidase method) paraffin sections of normal human ureter ( n = 18 ) and urinary bladder ( n = 10 ) using rabbit antibodies against UPIa, UPIb, UPII and UPIII; a recently raised mouse monoclonal antibody (MAb), AU1, and two new MAbs, AU2 and AU3, all against UPIII; and mouse MAbs against umbrella cell-associated cytokeratins CK18 and CK20. Immunoblotting showed that AU1, AU2 and AU3 antibodies all recognized the N-terminal extracellular domain of bovine UPIII. By immunohistochemistry, we found that in 15 18 cases of human ureter, but in only 2 10 cases of bladder, groups of normal-looking, CK18-positive umbrella cells lacked both UPIII and UPIb immunostaining. The UPIb/UPIII-negative cells showed either normal or reduced amounts of UPIa and UPII staining. These data were confirmed by double immunofluorescence microscopy. The distribution of the UPIb/UPIII-negative umbrella cells was not correlated with localized urothelial proliferation (Ki-67 staining) or with the distribution pattern of CK20. Similar heterogeneities were observed in bovine but not in mouse ureter. We provide the first evidence that urothelial umbrella cells are heterogeneous as some normal-looking umbrella cells can possess only one, instead of two, uroplakin pairs. This heterogeneity seems more prominent in the urothelium of human ureter than that of bladder. This finding may indicate that ureter urothelium is intrinsically different from bladder urothelium. Alternatively, a single lineage of urothelium may exhibit different phenotypes resulting from extrinsic modulations due to distinct mesenchymal influence and different degrees of pressure and stretch in bladder versus ureter. Additional studies are needed to distinguish these two possibilities and to elucidate the physiological and pathological significance of the observed urothelial and uroplakin heterogeneity.

Pressure-flow study of the upper urinary tract. 1. Pressure-flow study of the normal human ureter

Pressure-flow study of the upper urinary tract. 1. Pressure-flow study of the normal human ureter

A, B and H Antigens in Normal Urothelium: An Immunohistochemical Study Using Monoclonal Antibodies with the Avidin-Biotin Complex Technique

Immunohistochemical staining for the A, B and H blood group antigens was studied in 61 normal human ureters using monoclonal antibodies with avidin-biotin complex application. Thirty-seven of these were archival material, and 24 were processed prospectively. In 100 per cent of the prospectively processed ureters, A, B and H antigens were demonstrated corresponding to the blood type of the source. Archival material stained for A, B and H 65 per cent, 50 per cent and 100 per cent of the time, respectively. Serial sampling of prospectively processed ureters showed diminution of staining with prolongation of immersion in formalin. A characteristic staining pattern was found in ureters from patients with type B blood.

Ureteral Structure and Ultrastructure. Part I. The Normal Human Ureter

Twenty-eight normal human ureters were examined under the light and electron microscope. Three uretero-trigonal units were microdissected. The ureter is a non-layered muscular tube wherein the anatomical unit is muscle bundles that contain heterogeneously oriented muscle cells. Functional continuity of muscle cells is provided through the nexus, which are clearly defined structures. A group of morphologically distinct muscle cells are identified and these may represent the ureteral pacemaker cells. The functional status of muscle cells causes certain morphologic changes and, thus, the cells fixed in contraction differ from those fixed in relaxation and in vitro testing of muscle cell contractility is feasible.The ultrastructure of the normal urothelium and the adrenergic and cholinergic components of ureteral nerves are presented briefly.

Measurement of peristalsis of the ureter and its relation to drugs.

An electronic device, the electromanometer, was used to obtain a record of peristalsis of the normal human ureter before, during, and after the administration of morphine sulfate, atropine sulfate, propantheline, and atropine tannate in 31 patients. Because of its sensitivity the electromanometer can measure directly the absolute value of pressure in the ureter and the alterations that occur with peristalsis. It is used with a small-caliber catheter in order to avoid obstructive factors that were inherent in prior methods used to evaluate peristalsis of the ureter. The tracings obtained showed that these four drugs in the dosages used did not alter peristalsis of the ureter.

Electropotential Changes in the Normal Human Ureter

Electropotential Changes in the Normal Human Ureter

A Scientific Study of the Normal Human Ureter by Fractional Uretero Pyelography

A Scientific Study of the Normal Human Ureter by Fractional Uretero Pyelography