Altered urothelial ATP signaling in a major subset of human overactive bladder patients with pyuria.

Overactive Bladder (OAB) is an idiopathic condition, characterized by urgency, urinary frequency, and urgency incontinence, in the absence of routinely traceable urinary infection. We have described microscopic pyuria (≥10 wbc/µl) in patients suffering from the worst symptoms. It is established that inflammation is associated with increased ATP release from epithelial cells, and extracellular ATP originating from the urothelium following increased hydrostatic pressure is a mediator of bladder sensation. Here, using bladder biopsy samples, we have investigated urothelial ATP signaling in OAB patients with microscopic pyuria. Basal, but not stretch-evoked, release of ATP was significantly greater from the urothelium of OAB patients with pyuria than from non-OAB patients or OAB patients without pyuria (<10 wbc/µl). Basal ATP release from the urothelium of OAB patients with pyuria was inhibited by the P2 receptor antagonist suramin and abolished by the hemichannel blocker carbenoxolone, which differed from stretch-activated ATP release. Altered P2 receptor expression was evident in the urothelium from pyuric OAB patients. Furthermore, intracellular bacteria were visualized in shed urothelial cells from ∼80% of OAB patients with pyuria. These data suggest that increased ATP release from the urothelium, involving bacterial colonization, may play a role in the heightened symptoms associated with pyuric OAB patients.

[Relationships among urine pH, serum uric acid and pyuria in hospitalized elderly patients].

To identify risk factors of urinary tract infection (UTI) in geriatric patients, the levels of serum uric acid, serum creatinine, and urine pH were compared between pyuria-positive and -negative patients in a geriatric ward. The level of serum uric acid was higher with lower urine pH level in the pyuria-negative patients than in positive patients. The level of serum creatinine was relatively higher in the pyuria-negative patients than in the positive patients. Even after matching for serum creatinine, serum uric acid was significantly higher in the pyuria-negative male patients. The results in the present study proposed an interesting hypothesis about backgrounds for UTI in geriatric patients. The relationships among serum uric acid, serum creatinine, urine pH, and pyuria should be examined further in a larger population and in experimental studies.