An established macaque model to assess HIV interventions against penile transmission is currently not available. Physiological changes during penile erections may affect susceptibility to infection and drug pharmacokinetics (PK). Here, we identify methods to establish erections in macaques to evaluate penile transmission, PK, and efficacy under physiologic conditions.Methods
Penile rigidity and length were evaluated in eight rhesus macaques following rectal electrostimulation (RES), vibratory stimulation (VS), or pharmacological treatment with Sildenafil Citrate (Viagra) or Alprostadil.Results
Rectal electrostimulation treatment increased penile rigidity (>82%) and length (2.5 ± 0.58 cm), albeit the response was transient. In contrast, VS alone or coupled with Viagra or Alprostadil failed to elicit an erection response.Conclusion
Rectal electrostimulation treatment elicits transient but consistent penile erections in macaques. High rigidity following RES treatment demonstrates increased blood flow and may provide a functional model for penile PK evaluations and possibly simian immunodeficiency virus (SIV) transmission under erect conditions.