Urothelial Differences in the Exstrophy-Epispadias Complex: Potential Implications for Management.

PURPOSE: The authors examined the urothelium of exstrophy-epispadias complex spectrum patients for histological differences and expression of terminal markers of urothelial differentiation. MATERIALS AND METHODS: Between 2012 and 2017 bladder biopsies were obtained from 69 pediatric exstrophy-epispadias complex patients. These specimens were compared to bladder specimens from normal controls. All bladder specimens underwent histological assessment followed by immunohistochemical staining for uroplakin-II and p63. Expression levels of uroplakin-II and p63 were then assessed by a blinded pathologist. RESULTS: Forty-three classic bladder exstrophy biopsies were obtained (10 newborn closures, 22 delayed closures, and 11 repeat closures). Additional biopsies from 18 cloacal exstrophy patients and 8 epispadias patients were also evaluated. These specimens were compared to 8 normal control bladder specimens. Overall, uroplakin-II expression was lower in exstrophy-epispadias complex patients compared to controls (p <0.0001). Among classic bladder exstrophy patients, there was reduced expression of uroplakin-II in the delayed and repeat closures in comparison to newborn closures (p=0.045). Expression of p63 was lower in patients with exstrophy-epispadias complex compared to controls (p <0.0001). Expression of p63 was similar among classic bladder exstrophy patients closed as newborns when compared to delayed or repeat closures. Classic bladder exstrophy patients had a higher rate of squamous metaplasia when compared to controls (p=0.044). Additionally, there was a higher rate of squamous metaplasia in the patients undergoing delayed closure in comparison to those closed in the newborn period (p <0.001). CONCLUSIONS: The urothelium in the exstrophy-epispadias complex bladder is strikingly different than that of healthy controls. Uroplakin-II expression is greatly reduced in exstrophy-epispadias complex bladders and is influenced by the timing of bladder closure. Reduced uroplakin-II expression and increased rates of squamous metaplasia in exstrophy-epispadias complex patients undergoing delayed closure suggests that exposure of the urothelium may induce these changes. These findings shed light on the molecular changes in exstrophy-epispadias complex bladders and may have implications on the appropriate timing of primary bladder closure, as those closed in the newborn period appear to have a greater potential for growth and differentiation.

A combination of p40, GATA-3 and uroplakin II shows utility in the diagnosis and prognosis of muscle-invasive urothelial carcinoma.

Recently developed antibodies against uroplakin II and ΔNp63 (p40) show utility in diagnosing primary bladder urothelial carcinoma, although application in metastatic bladder cancer and patient outcomes has been less well defined. We evaluated these antibodies by immunostain intensity and H-score, in conjunction with GATA-3 immunoreactivity, in 89 patients with muscle-invasive urothelial carcinoma and 35 paired metastasis. The maintenance of immunoreactivity in metastatic lesions and the association to disease recurrence and survival was assessed. Bladder urothelial carcinoma showed immunoreactivity for GATA-3 in 99% (88/89), p40 in 87% (77/89) and uroplakin II in 80% (71/89) of cases, with a positive correlation between GATA-3 and uroplakin II H-score (0.44; p < 0.0001). All lesions were positive for at least one marker, reinforcing the use of these markers as a panel. In 35 patients with paired lymph node metastasis, uroplakin II and GATA-3 were retained in 90% and 75% of patients, respectively, suggesting these markers may have relatively high sensitivity in diagnosing metastatic urothelial carcinoma. High intensity p40 immunostain (3+), however, was significantly associated with reduced patient survival (p = 0.03). These results suggest that whereas GATA-3 and uroplakin II may be most useful in the diagnosis of urothelial carcinoma metastasis, p40 may be additionally suited as a prognostic marker.

Uroplakin II is a more sensitive immunohistochemical marker than uroplakin III in urothelial carcinoma and its variants.

OBJECTIVES: Uroplakin (UP) II and UPIII are highly specific immunohistochemical markers for urothelial differentiation. Here we studied the sensitivity of UPII and UPIII in conventional and variant urothelial carcinomas (UCs). METHODS: Immunohistochemical staining for UPII and UPIII was performed on tissue microarray slides, including 105 conventional bladder UCs (BUCs), 90 upper urinary tract UCs (UUTUCs), and 47 micropapillary, 16 plasmacytoid, 22 small cell carcinoma, and 41 sarcomatoid UC variants. RESULTS: UPII expression was significantly higher than UPIII expression in conventional BUC (44% vs 17%, P < .001) and UUTUC (67% vs 46%, P = .045). UPIII expression was significantly higher in UUTUC than in BUC (P < .001). In UC variants, UPII expression was significantly higher than UPIII expression in micropapillary (91% vs 25%, P < .001), plasmacytoid (63% vs 6%, P < .001), and sarcomatoid (29% vs 5%, P = .032) variants. Only rare cases of the small cell carcinoma variant had focal UPII and UPIII expression. Compared with conventional UC, the sarcomatoid variant had significantly lower UPII expression, whereas the micropapillary variant had significantly higher UPII expression (P < .001). CONCLUSIONS: UPII demonstrates a significantly higher sensitivity than UPIII in conventional and variant UCs. Thus, UPII is a more valuable marker than UPIII in immunohistochemical analyses for confirming the urothelial origin of carcinomas.

Urothelial differentiation of human umbilical cord-derived mesenchymal stromal cells in vitro.

Human umbilical cord-derived mesenchymal stromal cells (hUCMSCs) are the most primitive of those isolated from other post-natal tissue source. The hUCMSCs possess the capability of differentiating along multi-lineage. This study aimed to investigate whether hUCMSCs can differentiate into urothelium-like cells. The hUCMSCs were isolated from fresh human umbilical cord postpartum and expanded at least to passage 3 in vitro. Subsequently, they were cultured with conditioned medium from urothelial cells (UC-CM) supplemented with 20 ng/ml exogenous epidermal growth factor (EGF). Urothelial cell specific marker uroplakin II (UPII) and cytokeratins were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence technology. During culture, hUCMSCs started to express UPII and cytokeratins weakly at 7 days and were significantly up-regulated at 2 weeks post-induction. Additionally, morphology of hUCMSCs changed from spindle-shape to a polygonal epithelial-shape similar to that of urothelial cells after 7 days. The study results indicated that hUCMSCs can differentiate into urothelium-like cells in a defined micro-environment in vitro constituted by UC-CM and exogenous EGF.

Intravesical epinephrine preserves uroplakin II expression in urinary bladder from cyclophosphamide-induced rat cystitis.

We investigated the attenuated effect of intravesical epinephrine (EPI) on uroplakin II (UPII) expression in cyclophosphamide (CYP)-induced rat cystitis. Sixty-eight Sprague-Dawley female rats were divided into one negative control group (GI) and five intraperitoneally CYP (150 mg CYP/kg)-injected groups (GII-VI) consisting of a positive control group (GII), three groups (GIII-V) with retaining intravesically instillated ameliorating agents for 90 min by urethral ligation until sacrifice, and one group (GVI) with freely voiding after intravesical EPI instillation. The retention groups were further classified into null-treated- (GIII), EPI- (GIV), and vehicle group (GV). All rats were euthanized 24 h after CYP injection. The UPII and α1-adrenergic receptors (AR) levels were measured with real-time polymerase chain reaction (RT-PCR) method and the morphological changes were also evaluated. CYP induced severe cystitis and decreased vesical UPII mRNA level. The EPI-treated groups had showed attenuation effects against submucosal edema and hemorrhage, and preserved UPII expression. Concurrently, intravesical EPI resulted in a significant preservation of both subtypes of α1A- and α1B AR expressions, which was well correlated with the hemostatic pattern in the samples. The obstructed and null-treated group (GIII) revealed severe cystitis and maximally decreased UPII levels, and the diluting effect of vehicle (GV) on CYP toxicity was insignificant on UPII preservation. The UPII level of RT-PCR was well correlated with the UPII immunohistological expression and their morphological changes. Intravesical instillation of EPI preserves UPII expression and attenuates the toxic responses in the bladder in CYP-induced rat cystitis.

Expression and localization of four uroplakins in urothelial preneoplastic lesions.

In superficial umbrella cells of normal urothelium, uroplakins (UPs) are assembled into urothelial plaques, which form fusiform vesicles (FVs) and microridges of the apical cell surface. Altered urothelial differentiation causes changes in the cell surface structure. Here, we investigated ultrastructural localization of UPIa, UPIb, UPII and UPIIIa in normal and cyclophosphamide-induced preneoplastic mouse urothelium. In normal urothelium, terminally differentiated umbrella cells expressed all four UPs, which were localized to the large urothelial plaques covering mature FVs and the apical plasma membrane. The preneoplastic urothelium contained two types of superficial cells with altered differentiation: (1) poorly differentiated cells with microvilli and small, round vesicles that were uroplakin-negative; no urothelial plaques were observed in these cells; (2) partially differentiated cells with ropy ridges contained uroplakin-positive immature fusiform vesicles and the apical plasma membrane. Freeze-fracturing showed small urothelial plaques in these cells. We concluded that in normal urothelium, all four UPs colocalize in urothelial plaques. However, in preneoplastic urothelium, the growth of the uroplakin plaques was hindered in the partially differentiated cells, leading to the formation of immature FVs and ropy ridges instead of mature FVs and microridges. Our study demonstrates that despite a lower level of expression, UPIa, UPIb, UPII and UPIIIa maintain their plaque association in urothelial preneoplastic lesions.