Resveratrol-nitric oxide donor hybrid effect on priapism in sickle cell and nitric oxide-deficient mouse.

Background: Children and adult with sickle cell disease (SCD) display priapism associated with low nitric oxide (NO) bioavailability and oxidative stress in penis.
Aim: This study aimed to evaluate the effects of hybrid compound RVT-FxMe, derived from resveratrol bearing a NO-donor subunit, on two murine model that display priapism phenotype, SCD transgenic mice and endothelial NO synthase gene-deficient (eNOS-/-) mice.
Methods: Wild-type, SCD, and eNOS-/- mice were treated with RVT-FxMe (25 mg/kg/d, 2 weeks).
Outcomes: Hematological parameters, concentration-response curves to acetylcholine (ACh) and sodium nitroprusside (SNP), as well as to electrical field stimulation (EFS), were obtained in mice corpus cavernosum strips.
Results: Corpus cavernosum relaxations to SNP and EFS were increased in eNOS-/- group, which were normalized by RVT-FxMe treatment. SCD mice exhibited an excessive CC relaxant response induced by ACh, EFS and SNP RVT-FxMe treatment did not change the increased relaxant responses to ACh, EFS and SNP in corpus cavernosum from SCD group.
Clinical Translation: Excess of plasma hemoglobin in SCD may interfere in pharmacological activity of NO donors compounds.
Strength/limitations: While mechanistic data with promising potential is showed, the current study is not without limitations. RVT-FxMe effects in the mid- and long-term warrant complementary studies.
Conclusion: Treatment with RVT-FxMe reversed the enhanced NO-cGMP-mediated CC relaxations in eNOS-/- mice, but not in SCD mice; it is likely that excess of plasma hemoglobin in SCD mice act to inactivate NO before it reaches soluble guanylyl cyclase, avoiding restoration of NO bioavailability in penis.
Competing Interests: The authors have declared that no competing interests exist.