Potential urine biomarkers in bladder outlet obstruction-related detrusor underactivity

Detrusor underactivity (DU), an important but under-researched issue, is thought to be complex and multifactorial in etiology, pathophysiology, and diagnosis. Bladder outlet obstruction (BOO) is one of the important known etiologies of DU, with significant morphologic and physiologic changes of the urothelium, suburothelium, and detrusor muscle in the urinary bladder. Chronic urinary bladder ischemia and repeated cycles of ischemia and reperfusion injury cause excessive oxidative stress, and it is thought to be responsible for the development of DU. DU might be the late phase or decompensated status of BOO, with the possible mechanisms of afferent nervous dysfunction, increased inflammation, denervation of the detrusor muscle, and myogenic failure. Prostaglandin E2 (PGE2) involves in the physiological detrusor contraction, and might provide the prognostic value for the recoverability of DU. Neurotrophins, including nerve growth factor and brain-derived neurotrophic factor, involve in the neuroplastic changes in many inflammatory bladder diseases, including BOO and DU. Oxidative stress biomarkers, including 8-hydroxy-2-deoxyguanosine, F2-isoprostane, and the involved pro-inflammatory cytokines, have been applied in BOO due to their involvements in chronic bladder ischemia. PGE2, neurotrophins, inflammatory cytokines, and oxidative stress biomarkers are the potential urine biomarkers in BOO-related DU.