SPHK1 and overactive bladder: Nevertheless, our study suggests that SPK1 is expressed in the human bladder wall, specifically the urothelium, in bladder specimens from patients with NDO and additional studies are needed to confirm the role of SPK1/S1P pathway in the model of overactive bladder and a larger study is required to confirm these results and to further understand the role of this pathway in the pathogenesis of detrusor overactivity.