Testicular microvascular flow is altered in Klinefelter syndrome and predicts circulating testosterone

Abstract

ABSTRACTContextExperimental studies on Klinefelter syndrome (KS) reported increased intratesticular testosterone (T) levels coexisting with reduced circulating levels. Abnormalities in testicular microcirculation have been claimed; however, no studies investigated in vivo testicular blood flow dynamics in humans with KS.ObjectiveTo analyze the testicular microcirculation in KS by contrast-enhanced ultrasonography (CEUS) and correlate vascular parameters with endocrine function.Design and SettingProspective study. University Settings.Patients51 testicular scans, 17 testes from 10 T-naïve subjects with KS and 34 testes from age-matched eugonadal men (CNT) who underwent CEUS for incidental nonpalpable testicular lesions.Main OutcomesCEUS kinetic parameters.ResultsCEUS revealed slower testicular perfusion kinetics in subjects with KS than in age-matched CNT. Specifically, the wash-in time (Tin, p = 0.008), mean transit time (MTT, p = 0.008), time to peak (TTP, p < 0.001), and washout time (Tout 50%, p = 0.008) were all prolonged. Faster testicular blood flow was associated with higher total T levels. Principal component analysis and multiple linear regression analyses confirmed the findings, and supported a role for reduced venous blood flow as independent predictor of total T levels.ConclusionsTesticular venous blood flow is altered in KS and independently predicts T peripheral release.