Improving the barrier function of damaged cultured urothelium using chondroitin sulfate.

AIMS: To determine whether glycosaminoglycan (GAG) replenishment is able to improve recovery of a deficient urothelial barrier, chondroitin sulfate (CS) instillations were tested using an in vitro model. Porcine urothelial cells (Ucells) were terminally differentiated in culture conditions to construct a urothelial layer with a functional barrier. This layer was damaged to compromise barrier function to simulate a key characteristic of bladder pain syndrome/interstitial cystitis. The functional effect of subsequent treatment with CS was evaluated. METHODS: Primary porcine Ucells were isolated and cultured on inserts. Differentiation of cells was evaluated with immunohistochemical analysis for the presence of umbrella cells, tight junctions and CS. Transepithelial electrical resistance (TEER) measurements were performed to evaluate barrier function. Protamine was used to simulate mild urothelial damage. CS 0.2% (vol/vol), a GAG, was subsequently instilled in the treatment group. The recovery of barrier function was further evaluated with TEER measurements. The Student t test was used for the analysis of results. RESULTS: After induction of differentiation, the Ucells expressed barrier markers and a functional barrier was established (measured by high TEER). TEER decreased significantly after instillation with protamine. CS instillation improved recovery of TEER significantly measured after 7 hours (84% vs 22% in controls). After 24 hours; however, the TEER was comparable in both experimental groups. CONCLUSION: CS instillation improves the recovery of the urothelial barrier after damage in vitro. This functional experiment shows that CS improves recovery of damaged urothelial function, which supports the hypothesis behind the mechanism of action of GAG-replenishment therapy.

Urothelium update: how the bladder mucosa measures bladder filling.

AIM: This review critically evaluates the evidence on mechanoreceptors and pathways in the bladder urothelium that are involved in normal bladder filling signalling. METHODS: Evidence from in vitro and in vivo studies on (i) signalling pathways like the adenosine triphosphate pathway, cholinergic pathway and nitric oxide and adrenergic pathway, and (ii) different urothelial receptors that are involved in bladder filling signalling like purinergic receptors, sodium channels and TRP channels will be evaluated. Other potential pathways and receptors will also be discussed. RESULTS: Bladder filling results in continuous changes in bladder wall stretch and exposure to urine. Both barrier and afferent signalling functions in the urothelium are constantly adapting to cope with these dynamics. Current evidence shows that the bladder mucosa hosts essential pathways and receptors that mediate bladder filling signalling. Intracellular calcium ion increase is a dominant factor in this signalling process. However, there is still no complete understanding how interacting receptors and pathways create a bladder filling signal. Currently, there are still novel receptors investigated that could also be participating in bladder filling signalling. CONCLUSIONS: Normal bladder filling sensation is dependent on multiple interacting mechanoreceptors and signalling pathways. Research efforts need to focus on how these pathways and receptors interact to fully understand normal bladder filling signalling.

TRPV4 channels in the human urogenital tract play a role in cell junction formation and epithelial barrier.

AIM: The molecular interactions between transient receptor potential vanilloid subtype 4 channels (TRPV4) and cell junction formation were investigated in the human and mouse urogenital tract. MATERIALS AND METHODS: A qualitative study was performed to investigate TRPV4 channels, adherence junctions (AJs) and tight junctions (TJs) in kidney, ureter and bladder tissues from humans and wild-type and transgenic TRPV4 knockout (-/-) mice with immunohistochemistry, Western blotting, immunoprecipitation and reverse trasnscription-PCR. Cell junction formation in the wild-type and TRPV4 knockout (-/-) mouse was evaluated with immunohistochemistry and transmission electron microscope (TEM) techniques. RESULTS: TRPV4 channels are predominantly located in membranes of epithelial cells of the bladder, ureter and the collecting ducts of the kidney. There is a molecular interaction between the TRPV4 channel and the AJ. TEM evaluation showed that AJ formation is disrupted in the TRPV4 -/- mouse resulting in deficient intercellular connections and integrity of the epithelium. CONCLUSIONS: TRPV4 is believed to be a mechanoreceptor in the bladder. This study demonstrates that TRPV4 is also involved in intercellular connectivity and structural integrity of the epithelium.

Early free-flap debulking: avoiding the second donor site.

The advantages of this technique in large, shallow defects are: 1. The flap can be monitored clinically during the critical postoperative period. 2. The aesthetic result is much better than that of the bulky myocutaneous flap. 3. No second donor site for the split-thickness skin graft is required.

The extended submental island lip flap: an alternative for esophageal repair.

An esophagocutaneous fistula after total laryngectomy in a radiated field is rare. A 62-year-old man, with a history of T2N0 M0 laryngeal carcinoma, was treated with radiation therapy. He subsequently developed recurrent disease and underwent total laryngectomy. A complication of his total laryngectomy was a high esophagocutaneous fistula. The patient had no evidence of other disease. A functional repair was achieved by extending the submandibular arterial flap to incorporate the central third of the lower lip as a mucosomyocutaneous flap. This extension of the submandibular artery flap may preclude the need for jejunal free tissue transfer in some patients with esophagocutaneous fistula.

Cryptococcal infection of a prosthetic dialysis fistula.

Fungal infections of prosthetic dialysis fistulae are rare. We report the first case of infection of a polytetrafluoroethylene dialysis access graft with the yeast Cryptococcus neoformans. Therapy with antifungal agents alone failed to cure the infection and significant improvement was observed only when all prosthetic material was surgically removed. This case emphasizes the potential for fungal infection of prosthetic dialysis fistulae and the importance of removal of intravascular foreign material in conjunction with antifungal therapy for treatment of fungal prosthetic graft infections.

Angioedema presenting as chronic gastrointestinal symptoms.

Gastrointestinal complaints may be the presenting feature of patients with acquired or hereditary angioedema. We describe two patients with episodic nausea, abdominal pain, and cramping secondary to C1 inhibitor deficiency. In one patient, an acquired deficiency arose as a paraneoplastic syndrome with abdominal complaints preceding the diagnosis of an occult lymphoma. The second patient presented at age 61 with abdominal complaints secondary to a hereditary deficiency of C1 inhibitor. The patients' symptoms were due to gastrointestinal angioedema, resulting from episodic unregulated complement activation. The biochemical mechanism of this unusual syndrome and its diagnostic importance are discussed. A C1 inhibitor deficiency should be considered in patients with unexplained abdominal symptoms suggestive of intestinal pseudo-obstruction.

Detection and characterization of mupirocin resistance in Staphylococcus aureus.

Fourteen mupirocin-resistant Staphylococcus aureus strains were isolated over 18 months; 12 exhibited low-level resistance, while two showed high-level resistance. Highly mupirocin-resistant strains contained a large plasmid which transferred mupirocin resistance to other S. aureus strains and to Staphylococcus epidermidis. This plasmid and pAM899-1, a self-transferable gentamicin resistance plasmid, have molecular and biologic similarities.