The future of bladder research: Molecular profiling, new drug targets, gene therapy, and tissue engineering

Bladder smooth muscle organ culture preparation maintains the contractile phenotype

Smooth muscle cells, when subjected to culture, modulate from a contractile to a secretory phenotype. This has hampered the use of cell culture for molecular techniques to study the regulation of smooth muscle biology. The goal of this study was to develop a new organ culture model of bladder smooth muscle (BSM) that would maintain the contractile phenotype and aid in the study of BSM biology. Our results showed that strips of BSM subjected to up to 9 days of organ culture maintained their contractile phenotype, including the ability to achieve near-control levels of force with a temporal profile similar to that of noncultured tissues. The technical aspects of our organ culture preparation that were responsible, in part, for the maintenance of the contractile phenotype were a slight longitudinal stretch during culture and subjection of the strips to daily contraction-relaxation. The tissues contained viable cells throughout the cross section of the strips. There was an increase in extracellular collagenous matrix, resulting in a leftward shift in the passive length-tension relationship. There were no significant changes in the content of smooth muscle-specific α-actin, calponin, h-caldesmon, total myosin heavy chain, protein kinase G, Rho kinase-I, or the ratio of SM1 to SM2 myosin isoforms. Moreover the organ cultured tissues maintained functional voltage-gated calcium channels and large-conductance calcium-activated potassium channels. Therefore, we propose that this novel BSM organ culture model maintains the contractile phenotype and will be a valuable tool for the use in cellular/molecular biology studies of bladder myocytes.

Potential applications of gene therapy/transfer to the treatment of lower urinary tract diseases/disorders

Identification of molecular targets for novel therapeutics is a natural consequence of the age of molecular and personalized medicine. How this information is leveraged and applied to the treatment of functional diseases/disorders of the lower urinary tract will determine if this field of medicine can keep pace with technological developments and patient expectations for improved therapies. In this regard, therapeutic improvements for the treatment of lower urinary tract diseases and disorders have been largely incremental over the past 30 years. The goal of this report is to review the evidence pointing toward the enormous potential of gene therapy/transfer to provide a paradigm shift from palliative to curative therapeutic solutions for lower urinary tract diseases/disorders. In fact, it seems clear that gene therapy represents a biotechnology approach particularly suitable to applications in the lower urinary tract. Although much more research is required, ample preclinical evidence already indicates that, for example, gene therapy can favorably impact/alter virtually every aspect of bladder physiology/function. In short, further investigations and continued applications of gene therapy to the treatment of lower urinary tract diseases/disorders seems a prudent step toward potentially marked and more durable therapeutic improvements.

Gene therapy for male erectile dysfunction

The potential clinical advantages of a gene transfer therapy-based approach to treatment of genitourinary smooth muscle-based disorders are several: potential single therapy for restoration of normal bladder or erectile function; eliminating the need for daily medication; use in combination with other therapies to reduce dose requirements and side effects; and development of mechanism-based, patient-specific treatment approaches. With the safe administration of hMax-K to men with erectile dysfunction in the first human phase 1 trial and the initiation of the phase 1 trial of hMaxi-K for patients who have detrusor overactivity, we have entered an exciting new era in the development of safe enduring therapies for genitourinary disorders.