The Innovative Approach in Functional Bladder Disorders: The Communication between Bladder and Brain-Gut Axis

Functional bladder disorders including overactive bladder and interstitial cystitis may induce problems in many other parts of our body such as brain and gut. In fact, diagnosis is often less accurate owing to their complex symptoms. To have correct diagnosis of these diseases, we need to understand the pathophysiology behind overlapped clinical presentation. First, we focused on reviewing literatures that have reported the link between bladder and brain, as the patients with bladder disorders frequently accompanied mood disorders such as depression and anxiety. Second, we reviewed literatures that have described the relationship between bladder and gut. There exist many evidences of patients who suffered from both bladder and intestinal diseases, such as irritable bowel syndrome and inflammatory bowel disease, at the same time. Furthermore, the interaction between brain and gut, well-known as brain-gut axis, might be a key factor that could change the activity of bladder and vice versa. For example, the affective disorders could alter the activity of efferent nerves or autonomic nervous system that modulate the gut itself and its microbiota, which might cause the destruction of homeostasis in bladder eventually. In this way, the communication between bladder and brain-gut axis might affect permeability, inflammation, as well as infectious etiology and dysbiosis in bladder diseases. In this review, we aimed to find an innovative insight of the pathophysiology in the functional bladder disorders, and we could provide a new understanding of the overlapped clinical presentation by elucidating the pathophysiology of functional bladder disorders.