Prostatic Peptides and Chronic Prostatitis/Chronic Pelvic Pain Syndrome
Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a common but poorly understood condition that is defined only by symptoms. The mechanisms underlying the development of CP/CPPS are unknown but it is possible the condition has several causes. One of the potential etiologies for CP/CPPS is autoimmunity. Kouiavskaia et al (page 2483) from Baltimore, Maryland determined if T cells from men with CP/CPPS would recognize peptides derived from the normal self-prostatic proteins prostate specific antigen (PSA) and prostatic acid phosphatase (PAP).
The investigators purified CD4 T cells from the peripheral blood of 31 patients with CP/CPPS and from the buffy coat preparation of 27 normal male blood donors. The cells were stimulated in vitro with a panel of immunogenic peptides from PSA and PAP, and assayed for reactivity with the peptides by interferon-γ enzyme-linked immunosorbent spot assay. Intermediate resolution HLA typing was performed by polymerase chain reaction. Peptides were also tested by binding assay against different class II alleles. Peptide PAP173-192 was recognized more frequently by CD4 T cells from patients with CP/CPPS than from normal male blood donors. The recognition of PSA peptides was not statistically different comparing cases to normal male blood donors individually. However, peptide reactivity was more commonly observed in cases compared to normal donors for any PSA peptide or any tested peptide. All peptides showed a high level of promiscuity in the binding assays and there was no association of cases with any specific HLA class II phenotype at intermediate resolution. The authors conclude that their data support autoimmunity as a potential etiology for CP/CPPS in some patients, and suggest that immunosuppressive therapy might logically be tested for this complex, frustrating disorder.
Caveolin and Ultrastructure After Bladder Smooth Muscle Hypertrophy
It is well-known that bladder outlet obstruction can produce detrusor smooth muscle (DSM) hypertrophy and voiding dysfunction in men with benign prostatic hyperplasia. In male rabbits partial outlet obstruction causes bladder changes similar to those in men with benign prostatic hyperplasia. Previous studies have suggested that the obstruction induced hypertrophy causes ultrastructural changes including caveolae and intermediate size filaments. Caveolae and caveolins are implicated in many cellular processes including signal transduction, but the function of the intermediate filament system in smooth muscle is not well understood.
Using the rabbit partial outlet obstruction model Polyák et al (page 2497) from Philadelphia, Pennsylvania analyzed the caveolar structure and caveolin expression in DSM following hypertrophy. They processed sections of DSM from the bladder body for immunofluorescence and electron microscopy, and analyzed expression of caveolin isoform-1, 2 and 3 by Western blotting using specific antibodies against these proteins. They found that DSM cells from normal and hypertrophied bladders contain orderly arrays of thick and thin myofilaments interspersed with dense bodies. There was also an increase in intermediate size filaments in the hypertrophic DSM cells and the dense plaques in the inner membrane of hypertrophied DSM cells were longer than those of the control. DSM from hypertrophied bladder revealed a decreased number of caveolae and a lack of orderly distribution at the plasma membrane. Western blotting showed decreased expression of caveolin-1, 2 and 3 in hypertrophied DSM. The authors conclude that in the DSM of hypertrophied bladder decreased caveolae and caveolin protein levels might contribute to the altered signal transduction pathways that regulate the downstream effects of agonist induced contraction, including calcium sensitization, and that the increased number of intermediate size filaments is likely to alter the cytoskeletal structure, interfering with ability of the detrusor to develop passive and/or active force.
Restoration of Erectile Function by Antioxidant Therapy in Diabetic Rats
The most common risk factor for erectile dysfunction is diabetes mellitus. Diabetes mediates an increase in reactive oxygen species that can lead to impaired endothelial function, decreased smooth muscle in the corpus cavernosum and increased apoptosis. Hirata et al (page 2518) from San Francisco, California hypothesized that antioxidant therapy may restore erectile function through the inhibition of apoptosis in diabetic rat crura.
They randomized 40 male Sprague-Dawley rats to 5 groups of 8 animals each including 1) healthy controls, 2) rats with diabetes, 3) rats with diabetes with the antioxidant tempol (4-hydroxytetramethyl-piperidine-1-oxyl), 4) rats with diabetes with insulin, and 5) rats with diabetes with tempol and insulin. Intracavernous pressure (ICP) was measured, and levels of smooth muscle and collagen fibers were assessed by hematoxylin and eosin, and Masson's trichrome staining. Endothelial cells were assessed by CD31 staining and reactive oxygen species related genes were analyzed by cDNA microarray. The mRNA and protein expression profiles for these genes were confirmed by real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry. TUNEL assay was used to analyze apoptosis status.
Not unexpectedly the ICP in diabetic rats was significantly reduced vs controls. Treatment with tempol or insulin alone resulted in a significantly increased ICP compared to that of untreated diabetic rats. In the diabetic group mean smooth muscle area decreased significantly, and was restored after tempol and insulin combination treatment. The area of endothelial cells in diabetic rats was also significantly decreased and was not restored by any of the treatments used. However, apoptosis was restored to normal levels by a combination of insulin and tempol. Of 84 reactive oxidative stress and antioxidant genes 32 were identified specific to diabetic rats compared to healthy controls. The expression of uncoupling protein-3 (UCP3) was significantly increased in diabetic rats and normal levels were restored by all treatments. The authors conclude that tempol and insulin can restore erectile function in diabetic rats through the inhibition of apoptosis, and suggest that combined therapy using insulin and tempol may be an effective treatment for patients experiencing diabetic erectile dysfunction.
Urothelial Cancer Multidrug Resistance After Mitomycin C Exposure
Adjuvant intravesical chemotherapy at primary resection is well established as superficial bladder cancer management. In this context a factor pertinent to the design of cancer chemotherapy is multidrug resistance (MDR). In vitro models to study MDR commonly use resistant cell lines generated by continuous low dose drug exposure for many months, unlike the exposure experienced by residual superficial bladder cancer cells during chemotherapy adjuvant to resection.
It was previously shown that 3 short exposures to mitomycin C during 10 weeks could produce MDR. Birare et al (page 2472) from Southampton, United Kingdom now tested whether functional resistance could be detected after a single 1-hour insult. They exposed RT112 bladder cancer cells to a range of mitomycin C concentrations for 1 hour and cells regrew in 3 of 24 cultures (15.6, 3.91 and 0.98 mg/ml exposure). These cells were subjected to 3 functional tests of cross resistance to epirubicin including the MTT cytotoxicity assay, quantitative accumulation by flow cytometry and nuclear uptake or exclusion by live cell fluorescence microscopy. The investigators found clear indications of resistance by MTT assay and flow cytometry. Intracellular distribution, in which nuclear exclusion indicates resistance, was distinctively resistant in 1 subline and another 2 were equivocal. The authors conclude that variable (and perhaps nonpermanent) resistant phenotypes can be developed by a single exposure to mitomycin C for 1 hour in RT112 cells. Thus, some MDR potential exists even in a cloned cell line that is capable of surviving a single short drug exposure and expanding after that insult. Their results give added weight to considering MDR induction in dose scheduling or drug combinations for topical chemotherapy.
Restoring Barrier Function to Acid Damaged Bladder Using Chondroitin Sulfate
Although the etiology of interstitial cystitis (IC) is unclear, and although it may represent bladder manifestations of a more systemic disorder, it is clear that the pathophysiology of IC involves epithelial dysfunction. The bladder defense mechanisms comprise tight junction proteins and a dense layer of glycosaminoglycan on the specialized apical cells of the urothelium (umbrella cells). The barrier function is lost in IC, and to restore it chondroitin sulfate, which is less expensive and more inert than heparinoids, hyaluronan or pentosan polysulfate, has been introduced. The binding of chondroitin sulfate to damaged bladder as a function of the range of pH seen in urine, its efficacy in restoring the permeability barrier and the capacity of damaged bladder to bind chondroitin sulfate were studied by Hauser et al (page 2477) from Oklahoma City, Oklahoma.
In a mouse model of acid damage of the urothelium they investigated the binding of chondroitin sulfate to bladder urothelium quantitatively using chondroitin sulfate highly labeled with Texas Red® and quantitative fluorescence microscopy. In a rat model of bladder damage (acid) the efficacy of restoring barrier function was determined using the passage of intravesically instilled 86Rb through the urothelium into the bloodstream. The binding capacity of acid damaged bladder was determined by fluorometry. Chondroitin sulfate bound tightly and exclusively to the damaged mouse bladder surface but showed only minimal binding to undamaged bladder. There was no systematic variation with pH. In rats chondroitin sulfate instillation restored permeability to 86Rb to control levels. The authors conclude that chondroitin sulfate binds preferentially to damaged urothelium and restores the impermeability barrier, supporting the view that the glycosaminoglycan layer is a major contributor to the impermeability of bladder urothelium.
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