Ureteral cell cultures II: Collagen production and response to pharmacologic agents

Long-term outcomes of paclitaxel-coated balloons for non-malignant ureteral strictures

PURPOSE

To evaluate the clinical efficacy and safety of drug-coated balloon (DCB) ureteroplasty for the management of non-malignant ureteral strictures.

MATERIAL AND METHODS

A prospective "off-label" monocentric single-arm pilot study investigating the safety and efficacy of drug-coated balloon (DCB) (Lutonix^®; BD, USA) was performed. Twenty-five patients with benign ureteral strictures related to uretero-enteric anastomosis (n = 13); lithiasis (n = 5), post-surgical complications (iatrogenic n = 5), transplanted kidney (n = 1) and post-radiotherapy (n = 1) were included. Following lesion crossing, predilatation was performed using 4-7 mm high-pressure balloon catheter (5-6Fr) with a balloon pressure of 6-7 atm based on the manufacturer's recommendation. In the absence of rupture of the ureteral wall, the DCB was dilated for 4 min. across the lesion. The process was repeated if deemed necessary to a maximum of three stricture dilatations. We analysed both clinical and radiological primary patency (no signs of ipsilateral hydronephrosis or improvement of the existing residual dilatation at the follow-up examinations) and secondarily safety endpoints.

RESULTS

Mean lesion length was 40 ± 28.5 mm. Mean time follow up was 36 months ± 10.46 months. Strictures were located at upper ureteric (12%), lower ureteric (32%), ureterovesical anastomosis (4%) and uretero-enteric anastomosis (52%) levels. The overall radiological success at 1-year follow-up was 88% (22/25 patients). In 56% patients (14/25 patients with primary patency) the nephrostomy catheter was removed 21 days following a single DCB procedure. In 32% (8/25 patients) an additional dilatation sessions were required for maintaining the ureteral patency. The overall failure rate at 1-year follow-up was 12% (3/25 patients). Only one case of febrile urinary tract infection in a female patient (acute pyelonephritis) was encountered after the first dilatation.

CONCLUSIONS

Paclitaxel-coated balloon ureteroplasty proved to be safe and effective for the treatment of non-malignant ureteral strictures. Larger studies are warranted to validate these promising initial results.

Paclitaxel inhibits ureteral smooth muscle cell proliferation and collagen production in the absence of cell toxicity

PURPOSE

Urinary tract stricture results from excess collagen deposition at an injured area. Paclitaxel (Sigma-Aldrich®) prevents coronary artery restenosis by inhibiting vascular smooth muscle cell proliferation and collagen production. We evaluated the effects of paclitaxel on ureteral smooth muscle cell proliferation and collagen production.

MATERIALS AND METHODS

Three phases of experiments were done in canine smooth muscle cells. In phase 1 we used proliferation assay to study smooth muscle cells exposed to various concentrations of paclitaxel during 7 days. Phase 2 consisted of 6-day enzyme-linked immunosorbent assay to detect the total amount of type III collagen produced by smooth muscle cells exposed to paclitaxel. In phase 3 we assessed smooth muscle cell membrane damage using a lactate dehydrogenase cytotoxicity assay in which cells were exposed to escalating paclitaxel concentrations for 14 days.

RESULTS

Proliferation studies showed that 10 and 100 nM paclitaxel significantly inhibited ureteral smooth muscle cell proliferation. Enzyme-linked immunosorbent assay revealed significantly decreased type III collagen production at 100 nM. Cytotoxicity testing showed that 1 to 100 nM paclitaxel did not harm smooth muscle cells.

CONCLUSIONS

Paclitaxel effectively inhibits canine ureteral smooth muscle cell proliferation and collagen production without toxicity to smooth muscle cells at concentrations up to 100 nM. These results may ultimately translate into new methods of preventing and treating urinary stricture disease.

Collagen Changes in the Ureteropelvic Junction after Failed Antegrade Endopyelotomy

PURPOSE

We evaluated the collagen content and differentiation of the ureteropelvic junction (UPJ) of patients who underwent Anderson-Hynes dismembered pyeloplasty after failure of antegrade endopyelotomy.

MATERIALS AND METHODS

A total of 12 UPJ obstructions were examined more than 12 months after endopyelotomy with both histochemical staining to analyze total collagen content and immunohistochemical staining to analyze collagen types I and III. The specimens were compared with 12 primary UPJ obstructions and 6 normal UPJs. Statistical analysis was performed using Fisher's test and Wilcoxon matched-pairs signed-rank test.

RESULTS

Immunohistochemical staining revealed that collagen type I was located in the interfascicular space and collagen type III in the intrafascicular space in all UPJs. We found more collagen in obstructed than in normal UPJs. Collagen type III was more abundant in secondary than in primary UPJ obstructions (P < 0.01). In obstruction after endopyelotomy, the staining intensity of collagen type III was greater than the intensity of collagen type I (P < 0.01).

CONCLUSION

Our results suggest that the success of antegrade endopyelotomy was impaired by an inflammatory process. This condition determined a shift of collagen differentiation toward type III, which is more fibrous than type I.

[Current status of tissue engineering in urology. Review of the literature]

In the eighties a new field of the medicine appears wich applies the principles of cellular cultivation to synthetic biodegradable polymers scaffolds with the purpose of creating autologous biological substitutes that could improve, maintain or restore the function of organs or damaged tissues. The Tissue Engineering constitutes a new discipline in full phase of development especially in USA, with multiple potential applications in several medical specialities. Our speciality can't remain indifferent to interest and encouraging future originated by this new science. In this work we have made a wide bibliographical revision in the Medline to know the antecedents, current state and the possible future applications of Tissue Engineering in Urology.

Ureteroscopic endoureterotomy

OBJECTIVE

To highlight the current status of ureteroscopic endoureterotomy (UE) by reporting extensive experience with the endoscopic management of ureteric strictures, with special emphasis on factors determining success, and by reviewing publications on the minimally invasive management of ureteric strictures.

PATIENTS AND METHODS

The study comprised 50 patients (mean age 53 years, range 18-85, equal sex distribution) with ureteric strictures of varying causes; all had their stricture treated endoscopically. The follow-up was 0.5-9 years; 10 patients with recurrent strictures had two ipsilateral stents placed to try to improve the outcome, and eight patients with completely obliterating strictures were treated by ureteroscopic re-canalization.

RESULTS

The site of stricture had no bearing on the eventual outcome. Patients with uretero-enteric and malignant strictures did not fare so well. The most important predictor of failure was the length of the stricture, with failure in all seven patients with strictures of > 2 cm. In the 10 patients treated with two ipsilateral stents, eight were successful, which was very promising considering that these patients had recalcitrant strictures and placing one stent had previously failed. The overall success rate was 74%.

CONCLUSION

UE has become the procedure of choice for the initial management of ureteric strictures. Simple balloon dilatation is also effective in certain situations. The characteristics of the stricture often govern the eventual outcome. In properly selected cases success rates of approximately 75% can be expected.

Surface modification to improve in vitro attachment and proliferation of human urinary tract cells

OBJECTIVE

To evaluate the attachment and proliferation of cultured human urinary tract cells to culture plates surface-modified by photochemical immobilization of extracellular matrix (ECM) proteins.

MATERIALS AND METHODS

Human uroepithelial (UEC) and smooth muscle (SMC) cells were harvested from ureter and expanded in culture; 24-well culture plates surface-modified by photochemical covalent immobilization of ECM proteins were then seeded with UEC or SMC. To characterize cellular attachment, cells were incubated on surface-modified plates for 30 and 90 min. For proliferation assays the cells were incubated for 3-12 days. Standard tissue culture plates with no surface modification and sham-modified plates served as controls. Differential attachment and proliferation on the various surfaces were assessed using analysis of variance with Fisher's posthoc test for multiple comparisons.

RESULTS

Attachment at 30 and 90 min of both UEC and SMC on plates surface-modified with ECM proteins was significantly greater than in control plates. Surface-modification with collagen resulted in significantly greater cellular attachment than with either laminin or fibronectin. UEC proliferation was also significantly greater than in control plates by surface-modification with collagen and fibronectin, but not with laminin. SMC proliferation was significantly better after surface modification than on sham- modified plates, but was no better than standard plates.

CONCLUSIONS

Covalent photochemical immobilization of ECM proteins to potential growth surfaces enhances the attachment of cultured UEC and SMC and the proliferation of UEC. This technique might be useful in modifying surface properties of synthetic polymer-based materials in a controlled and defined manner, giving them the capacity to promote and sustain the growth of urinary tract cells. This may lead to development of alternative methods of tissue engineering in the urinary tract.

Intralesional verapamil for the treatment of Peyronie's disease: a review

Multiple treatment options have been used for Peyronie's disease (PD) including intralesional injection of the calcium antagonist verapamil. The use of verapamil is based on its capacity to alter fibroblast function at several levels, including cell proliferation, extracellular matrix protein synthesis and secretion, as well as collagen degradation. Consequently, calcium antagonists may have the capacity to slow, prevent, or even reverse plaque formation and the progression of PD. The multicenter international experience with intralesional verapamil injection suggests that the majority of men with PD that receive treatment demonstrate durable reduction in pain, decrease in curvature, and improved sexual function. We review the scientific rationale, published literature, clinical experience, and technique of intralesional injection of verapamil.

Cultured differentiated human urothelial cells in the biomaterials field

To review the use of normal cultured differentiated human urothelial cells in the biomaterials field, we checked the literature for human urothelial cells in culture (HUC) both for their use in biocompatibility assessment and as bioartificial devices. The in vitro culture of differentiated human urothelium is now a simple and reliable procedure. These techniques provide new tools for biocompatibility assessment of urinary biomaterials, because for the rational design of a testing procedure, it is preferable that the particular cell culture models selected should be closely related to the end-use application. The emerging use of HUC culture should lead to the development of bioartificial tissue for urinary tract reconstruction. Tissue engineering techniques require urothelial cells and cell delivery matrices. The cytocompatibility of novel artificial delivery matrices should be assessed in vitro before implantation using cultured HUC to find the best material available.

Use of epidermal growth factor and collagen synthesis inhibition as adjuvant to healing of ureteroureteral anastomosis

BACKGROUND AND PURPOSE

When treating a ureteral narrowing by endopyelotomy or endoureterotomy, the urologist hopes that after the narrowed area is cut, it will heal with a patent lumen. A ureteral stent is usually left in place to provide a framework for healing. In cases of failure, histologic examination shows a predominance of collagen. We evaluated the effects of epidermal growth factor (EGF) and a collagen synthesis inhibitor, halofuginone, as adjuncts to ureteral healing.

MATERIALS AND METHODS

Ten female pigs underwent ureteroureteral anastomosis bilaterally, with the left side being stented. They were then randomized to receive EGF (N = 4), halofunginone (N = 3), or saline (control; N = 3). On postoperative day 30, the ureters were examined grossly and histologically.

RESULTS

The lumens of the ureters were significantly larger in the animals that received either EGF or funginone than in the control animals. The epithelium was significantly thicker in the animals that received halofunginone than in the controls or animals receiving EGF. The thickness of the smooth muscle and adventitia was similar in the three groups. Stenting improved the results.

CONCLUSION

Both EGF and halofuginone show promise as adjuncts to endopyelotomy and endoureterotomy.

Glucocorticoid resistance caused by reduced expression of the glucocorticoid receptor in cells from human vascular lesions

Mechanisms that control the balance between cell proliferation and death are important in the development of vascular lesions. Rat primary smooth muscle cells were 80% inhibited by low microgram doses of hydrocortisone (HC) and 50% inhibited by nanogram concentrations of transforming growth factor-beta1 (TGF-beta1), although some lines acquired resistance in late passage. However, comparable doses of HC, or TGF-beta1, failed to inhibit most human lesion-derived cell (LDC) lines. In sensitive LDC, HC (10 microg/mL) inhibited proliferation by up to 50%, with obvious apoptosis in some lines, and TGF-beta1 inhibited proliferation by more than 90%. Collagen production, as measured by [3H]proline incorporation or RIA for type III pro-collagen, was either unaffected or increased in the LDCs by HC. These divergent responses between LDC lines were partially explained by the absence of the glucocorticoid receptor (GR) and heat shock protein 90 mRNA in 10 of 12 LDC lines, but the presence of the mineralocorticoid receptor and 11beta-hydroxysteroid dehydrogenase type II. Western blot analysis confirmed the absence of the GR protein in cells lacking GR mRNA. Immunohistochemistry of human carotid lesions showed high levels of GR in the tunica media, but large areas lacking GR in the fibrous lesion. Considering the absence of the GR in most lines, the effects of HC may be elicited through the mineralocorticoid receptor. Functional resistance to the antiproliferative and antifibrotic effects of HC may contribute to excessive wound repair in atherosclerosis and restenosis.