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.

Is chronic urinary infection a cause of overactive bladder?

Overactive bladder (OAB) is a diagnosis resulting from a combination of multiple underlying factors. Current traditional treatments are based on anticholinergic blockade which have marginal benefits and are associated with poor tolerability and continuation rates. There is mounting evidence that chronic low grade bacterial bladder colonisation may exacerbate OAB symptoms and may explain why the current treatment strategies are not always successful. However, standard diagnostic laboratory tests to identify the presence of such bacterial infection are unreliable. Newer technologies such as RNA sequencing and extended culture techniques, show that urine is not sterile and organisms that are found in urine may be responsible for OAB symptoms. This article aims to review the current evidence suggesting that micro-organisms in urine may be important in the aetiology of OAB or may exacerbate OAB symptoms.

Development of a real-time probe-based PCR assay for the diagnosis of Pneumocystis pneumonia.

This paper describes the development of a rapid probe-based real-time polymerase chain reaction assay (PCR) for the diagnosis of Pneumocystis pneumonia. To develop the PCR, primers and fluorescent resonance energy transfer probes were designed after sequencing products obtained using previously published primers. This gave results that were concordant with conventional cytological staining techniques, but were available within 2 h instead of greater than 24 h.