Diabetes mellitus affects more than 100 million people worldwide. Neuronal alterations, as a consequence of diabetes mellitus can cause bladder dysfunction ranging from mild to severe in scope. In fact, urinary incontinence occurs in up to 80 percent of diabetic patients, and the manifestations include decreased bladder sensation, increased residual urine or detrusor instability (i.e., bladder overactivity or hyperactivity). These conditions have a severely adverse effect on the quality of life of the individual, at great monetary as well as emotional expense. These diabetes-related changes in bladder function are permanent and require medical therapy to reverse the symptoms. Current medical therapies lack both efficacy and specificity. To this end, we propose to evaluate the efficacy of K channel gene therapy to ameliorate the bladder hyperactivity associated with the most commonly used animal model of diabetic neuropathy (as determined by reference citations), that is, the streptozotocin (STZ)-diabetic rat. We shall study the effects of STZ-induced diabetes on bladder function in vivo in MALE and FEMALE rats.
In Specific Aim #1 we will utilize the micturition reflex to study bladder function in conscious and freely moving rats, and thereby identify those animals exhibiting STZ-induced bladder overactivity. Rats with documented bladder hyperactivity will receive a single injection of the hSlo/pcDNA, which encodes the alpha subunit of the human maxi-K (potassium) channel.
In Specific Aim #2 we will utilize in situ hybridization techniques to establish the relationship between recombinant transgene expression (i.e., hSlo/pcDNA expression) and bladder function in the same animal. Such studies will permit us to firmly establish the relationship between transfection efficiency and organ function in vivo in the same animal.
In Specific Aim #3, we will utilize microarray gene chip analysis to study the effects of STZ-Diabetes on gene expression in the bladder of rats that have already been characterized with respect to the degree of bladder dysfunction in vivo. Moreover, we will also examine the effects of hSlo gene therapy on gene expression. As such, we anticipate being able to establish definite relationships between the degree of transgene expression, and the effects of these molecular changes on bladder function in vivo. In year 2 of this proposal we will study the prophylactic ability and duration of this gene therapy approach.
| Yoshimura, Naoki; Chancellor, Michael B; Andersson, Karl-Erik et al. (2005) Recent advances in understanding the biology of diabetes-associated bladder complications and novel therapy. BJU Int 95:733-8 |
| Christ, George J; Liebert, Monica (2005) Proceedings of the Baltimore smooth muscle meeting: identifying research frontiers and priorities for the lower urinary tract. J Urol 173:1406-9 |
