Relationship Between Amyloid Precursor Protein in Seminal Plasma and Abnormal Penile Sympathetic Skin Response in Lifelong Premature Ejaculation

Abstract

IntroductionHyperactivity of the sympathetic nervous system can play an important role in lifelong premature ejaculation (PE). Our previous study found that amyloid precursor protein (APP) levels in seminal plasma of patients with PE were clearly increased. Amyloid-β (Aβ) is derived from APP. Excessive Aβ, especially Aβ42, can cause neuronal dysfunction. AimTo determine whether APP and Aβ42 are associated with an abnormal penile sympathetic skin response (PSSR). MethodsFrom November 2015 to April 2016, 24 patients with lifelong PE (mean age = 29.2 ± 5.3) with self-estimated intravaginal ejaculatory latency time no longer than 2 minutes and 10 control subjects (mean age = 28.0 ± 5.5) were enrolled consecutively from andrology clinics. PSSR was measured in patients with lifelong PE. APP and Aβ42 levels in seminal plasma were determined. Main Outcome MeasuresPSSR in patients with lifelong PE and APP and Aβ42 levels in all subjects. ResultsPatients with PE presented 1.5-fold higher levels of APP (P = .004) than control subjects. Seminal plasma protein concentration (C) in the PE group was lower than that in the control group (P = .007). APP divided by C (APP/C) was 2.0-fold higher (P < .001) in the PE group. Aβ42 level was not different between the PE and control groups, but Aβ42 divided by C (Aβ42/C) was significantly higher in the PE group (P < .001). No differences in APP and APP/C were found between patients with PE in the abnormal and normal PSSR groups. The abnormal PSSR group presented significantly higher Aβ42 (P = .007) and Aβ42/C (P < .001) levels. The latency of PSSR was negatively correlated with Aβ42/C (r = −0.436; P = .033). ConclusionThese results showed that patients with lifelong PE had higher APP and Aβ42 levels in seminal plasma. Abnormal PSSR was related to a higher Aβ42 level. Drugs that decrease Aβ could be treatment of PE.