Erectile dysfunction in systemic sclerosis: effects of longterm inhibition of phosphodiesterase type-5 on erectile function and plasma endothelin-1 levels.
OBJECTIVE
To investigate the effects of prolonged inhibition of phosphodiesterase type-5, using once-daily long-acting phosphodiesterase type-5 inhibitor (tadalafil) on erectile function and biomarkers of endothelial function in male patients with systemic sclerosis (SSc) and erectile dysfunction (ED).


METHODS
In an open-label study, 14 nonconsecutive male patients with SSc with different degrees of ED were enrolled into the study irrespective of their clinical response to tadalafil, and received once-daily tadalafil 10 mg for 12 weeks. Primary endpoints were variations from baseline of penile arterial inflow [peak systolic velocity (PSV, cm/s); measured with dynamic color duplex ultrasound] and the erectile function domain score (measured with the International Index of Erectile Function questionnaire). Secondary endpoints were variations from baseline of morning erections (determined by modified question 13 of the Structured Interview on Erectile Dysfunction questionnaire) and plasma concentrations of endothelin-1 (ET1).


RESULTS
The PSV and the erectile function domain score were significantly improved by once-daily tadalafil (from 21.3 +/- 6.4 to 30.0 +/- 7.0 cm/s and from 13.0 +/- 6.8 to 17.0 +/- 9.0 vs baseline, respectively; p <0.05). Question 13 scores decreased dramatically after treatment compared with baseline (from 2.2 +/- 0.2 to 0.8 +/- 0.5 arbitrary units; p < 0.001), and plasma ET1 levels decreased (from 24 +/- 15 to 9.8 +/- 7.4 pg/ml; p < 0.05).


CONCLUSIONS
In men with SSc-related ED, once-daily tadalafil improved both erectile function and vascular measures of cavernous arteries. Increases in morning erections and decreases in plasma ET1 levels were found, which may play a potential role in preventing progression of penile fibrosis and erectile dysfunction.
Proietti
Michele
M
Department of Clinical Immunology and Allergy, Department of Medical Pathophysiology, University of Rome La Sapienza, Rome, Italy. michele.proietti@tin.it
Aversa
Antonio
A
Letizia
Claudio
C
Rossi
Carmelina
C
Menghi
Ginevra
G
Bruzziches
Roberto
R
Merla
Arcangelo
A
Spera
Giovanni
G
Salsano
Felice
F
D000328:Adult; D002243:Carbolines / Q000627:therapeutic use*; D018450:Disease Progression; D019332:Endothelin-1 / Q000097:blood*; D007172:Erectile Dysfunction / Q000188:drug therapy* / Q000209:etiology*; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D058986:Phosphodiesterase 5 Inhibitors; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D012595:Scleroderma, Systemic / Q000097:blood / Q000150:complications*; D000068581:Tadalafil
D002243:Carbolines; D019332:Endothelin-1; D058986:Phosphodiesterase 5 Inhibitors; D010726:Phosphodiesterase Inhibitors; D000068581:Tadalafil