An interventional study of Daily low-dose PDE5 inhibitor therapy and Testosterone therapy as per clinical guidelines. in Erectile Dysfunction, Hypogonadism, Male and Endothelial Dysfunction, sponsored by University of California, Irvine. Recruiting at 1 site in United States. Open to male participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-02-02.
Sponsored by University of California, Irvine · Not applicable, Interventional, and Diagnostic
To assess endothelial dysfunction in young men (aged 30-50) with vasculogenic ED identified through penile Doppler ultrasound.
To evaluate changes in endothelial function using EndoPAT before and 3-6 months after daily low-dose phosphodiesterase type 5 (PDE5) inhibitor therapy.
To investigate endothelial function alterations in hypogonadal patients before and 3-6 months after initiating testosterone (T) therapy
Endothelial Dysfunction and Cardiovascular Health: Endothelial dysfunction is characterized by impaired endothelium-dependent vasodilation, which is a critical factor in the development and progression of cardiovascular diseases. The endothelium, the thin layer of cells lining blood vessels, plays a pivotal role in vascular health by regulating blood flow, coagulation, and immune function. When the endothelium is not functioning properly, it can lead to a range of cardiovascular conditions, including atherosclerosis, hypertension, and erectile dysfunction (ED).
Erectile Dysfunction and Endothelial Dysfunction: ED is often an early marker of endothelial dysfunction and cardiovascular diseases. Vasculogenic ED, in particular, is linked to poor endothelial health, where impaired blood flow to the penile tissue results in the inability to achieve or maintain an erection. This condition shares common risk factors with other cardiovascular diseases, such as diabetes, hypertension, and hyperlipidemia, highlighting the interconnected nature of endothelial health and ED.
Hormonal Therapy and Endothelial Function: Testosterone therapy (T therapy) is commonly used to treat hypogonadism in men, a condition characterized by low testosterone levels. Hypogonadism itself is associated with an increased risk of cardiovascular diseases, and testosterone therapy has been shown to have varying effects on endothelial function. While some studies suggest that testosterone may improve endothelial health, others indicate potential risks, necessitating further research to clarify its impact.
Current Gaps in Knowledge:
Prevalence of Endothelial Dysfunction in Young Men with ED: While the association between endothelial dysfunction and ED is established, there is a need for precise data on the prevalence and extent of endothelial dysfunction specifically in young men with vasculogenic ED. Understanding this prevalence can inform targeted treatment strategies.
Impact of PDE5 Inhibitors on Endothelial Function: Phosphodiesterase type 5 (PDE5) inhibitors are a first-line treatment for ED, known to improve erectile function by enhancing blood flow. However, their direct impact on endothelial function over time remains underexplored, particularly in terms of long-term cardiovascular outcomes.
Effects of Testosterone Therapy on Endothelial Health: The influence of testosterone therapy on endothelial function in hypogonadal men is not well understood. There is conflicting evidence on whether testosterone therapy confers cardiovascular benefits or risks, necessitating comprehensive studies to determine its effects.
701 studies on the registry are indexed under Erectile Dysfunction; 125 are open to participants now.
This study's planned enrollment of 120 is above the median of 70 across 551 interventional studies indexed under Erectile Dysfunction.
Browse Erectile Dysfunction studies →University of California, Irvine is the lead sponsor of 476 studies on the registry; 98 are open to participants now.
Of its 41 completed or terminated interventional studies of FDA-regulated products, 30 (73%) have results posted.
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Exclusion Criteria:
Population: 40 men aged 18 or above years diagnosed with vasculogenic ED. Intervention: Daily low-dose PDE5 inhibitor therapy. Assessments: Endothelial function will be assessed using the EndoPAT device at baseline, 3 months, and 6 months post-intervention.
Drug: Daily low-dose PDE5 inhibitor therapy
Population: 40 hypogonadal men aged 18 or above Intervention: Testosterone therapy as per clinical guidelines. Assessments: Endothelial function will be assessed using the EndoPAT device at baseline, 3 months, and 6 months post-intervention.
Drug: Testosterone therapy as per clinical guidelines.
Population: 40 men aged 18 or above years diagnosed with vasculogenic ED. Intervention: None Assessments: Endothelial function will be assessed using the EndoPAT device at baseline, 3 months, and 6 months post-intervention.
Neither arm of the study includes a control group, and the two interventions will not be compared directly. The primary objective is to evaluate endothelial function using the EndoPAT device at baseline, 3 months, and 6 months following the intervention in each arm.
Neither arm of the study includes a control group, and the two interventions will not be compared directly. The primary objective is to evaluate endothelial function using the EndoPAT device at baseline, 3 months, and 6 months following the intervention.
Endothelial Function as Measured by Reactive Hyperemia Index (RHI)
Definition: RHI is a measure of endothelial function derived from the EndoPAT device, which assesses the endothelium's ability to respond to induced hyperemia. Measurement: RHI is calculated based on the changes in digital pulse volume during reactive hyperemia following a 5-minute arterial occlusion. Criteria for Evaluation: Baseline RHI: Measured before any intervention. Post-Intervention RHI: Measured at 3 months and 6 months post-intervention. Improvement in RHI: Defined as an increase in RHI scores from baseline to follow-up measurements.
Time frame: At baseline, 3 months, and 6 months post-intervention
Cardiovascular Health Markers
Successful Outcome: Statistically significant improvements in blood pressure, lipid profile, and blood glucose levels from baseline to 3 and 6 months. Failure: No significant changes or worsening of cardiovascular health markers.
Time frame: From baseline to 3 months and 6 months post-intervention.
Sexual Function Scores
Successful Outcome: Statistically significant improvement in IIEF scores from baseline to 3 and 6 months. Failure: No significant changes or deterioration in sexual function scores.
Time frame: From baseline to 3 months and 6 months post-intervention.
Adverse Events
Successful Outcome: Minimal and non-severe adverse events reported. Failure: High frequency or severe adverse events necessitating discontinuation of the intervention.
Time frame: From baseline to 3 months and 6 months post-intervention.
Plan to share: No
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Started Aug 2025 (actual). Primary completion is estimated for Jan 2027, 17 months after the start.
Of 115 non-industry interventional studies with no phase under Erectile Dysfunction, half reached primary completion within 30 months of starting (the median), counting those still running; a quarter within 15 and three quarters within 52. This study's planned 17 months is below that.
Counting every sponsor, half of 137 studies reached it within 32 months; a quarter within 14 and three quarters within 52.
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