Alterations of 2-pore Domain Potassium Channel Expressions in Bladder Mucosae of Urinary Incontinence Patients

Introduction and Objectives: Although there is an accumulation of data that suggest 2-pore domain potassium (K2P) channels are involved in diverse cellular functions such as cell excitability, signal transduction, apoptosis, and abnormal cell proliferation, and thus probably involved in many different physiological and pathophysiological processes, limited data are available for native K2P channel characteristics, including tissue-specific expression patterns and pharmacological properties. Thus, aims of this study were to examine if stretch-activated K2P channels such as TREK1, TREK2, and TRAAK expressed in bladder mucosa and to measure urinary incontinence-associated changes of RNA and protein levels.

Methods: Forty-five patients were included in our study. With cold-cup biopsy forceps, bladder mucosae have been obtained from patients with genuine stress urinary incontinence (SUI) (group 1, N = 18), SUI with frequency/urgency (group 2, N = 13), and mixed incontinence (group 3, N = 14), and then frozen immediately in liquid nitrogen for RNA and protein measurements using reverse-transcription polymerase chain reaction and western blot analysis, respectively.

Results: The mRNA of TREK1 was highly expressed in normal bladder mucosae, whereas the messages of TREK2 and TRAAK were rarely detected. TREK1 mRNA of group 1 in the pre-menopausal state was lower than that of other groups. The TREK1 protein content was highest in group 3.

Conclusions: These results suggest that TREK1 expressed in human bladder mucosa is probably involved in modulate bladder instability of urinary incontinence patients.