A Cross-Sectional Study Investigating Urinary Levels of Nerve Growth Factor and Its Precursor in Patients with Multiple Sclerosis

Background/Objectives: As multiple sclerosis (MS) progresses, most patients develop lower urinary tract symptoms (LUTS) indicative of an overactive bladder (OAB), primarily due to neurogenic detrusor overactivity, which is the most common abnormality identified during urodynamic testing. Therefore, biomarkers for OAB would be valuable additions to diagnostic tools. This study aimed to compare urinary levels of nerve growth factor (NGF) and its precursor, pro-NGF, in MS patients with and without OAB. Methods: We enrolled patients with relapsing MS (RMS), some exhibiting LUTS suggestive of OAB, along with healthy controls (HCs). Urine samples were collected, and NGF and pro-NGF levels were measured using ELISA kits. Results: Neither an ELISA kit specific for NGF nor a kit recognizing both NGF and pro-NGF detected measurable levels of these proteins. However, an ELISA kit selective for pro-NGF detected similarly low concentrations of this protein in a few samples from each group. Conclusions: Our ELISA results, measuring urinary NGF and pro-NGF levels in MS patients and HCs, are consistent with other studies that failed to detect these proteins in the urine of patients with OAB of various etiologies or in HCs. It is possible that urinary levels of NGF and pro-NGF are so low that the detection limits of ELISA kits and other available immunoassays are insufficient for their reliable measurement.