The present prospective study took place from August 2013 to March 2015 at a private practice urology clinic. The study was approved by the Western Institutional Review Board and registered at ClinicalTrials.gov (NCT02395029). All participants provided informed consent.
Patients who presented to the clinic with Peyronie disease and who did not want to pursue surgical options at that time were selected for study enrollment. Participants were included in the study if they were aged 18 years or older and had an acquired penile curvature associated with a palpable penile plaque at physical examination and penile plaque at ultrasonography screening.
Patients with any of the following conditions were excluded: current warfarin treatment; inability to achieve adequate erections with penile injection to allow assessment of penile curvature; history of definitive treatment for prostate, bladder, or other pelvic cancer (eg, surgery, external-beam radiation therapy, brachytherapy, cryotherapy); any history of prostate cancer, hematologic disorders, chronic liver disease (eg, cirrhosis, hepatitis C), immune system disorders (eg, human immunodeficiency virus infection), psychiatric disorders (eg, major depression, schizophrenia, bipolar disorder), cerebrovascular accident or deep venous thrombosis within the past 5 years, or severe sleep apnea; clinically significant abnormal laboratory results that (in the opinion of the investigator) would put the participant at increased risk or compromise the integrity of the study data; or any receipt of investigational drugs within the past 30 days.
Placental matrix–derived mesenchymal stem cells are a placental stem cell product that mixes mesenchymal stem cells with growth factors, cytokines, and an extracellular matrix to promote wound healing, angiogenesis, and tissue repair. Our PM-MSCs were derived from the chorionic placenta.
Patients were evaluated using penile ultrasonography to count and measure their Peyronie plaques. Before receiving any PM-MSC and trimix injections, they answered the International Index of Erectile Function (IIEF) questionnaire to determine their erectile function status.
Next, patients were injected with 0.2 mL of a trimix compounded solution as a control and for standardization of data to produce a penile erection. The trimix solution consisted of papaverine (30 mg), phentolamine (5 mg), and prostaglandin (50 μg). While the penis was erect, a protractor was used to measure the baseline angle of penile curvature. Curvature was measured on the concave side of the penile shaft, with the angle of curvature used as a fulcrum; essentially, the middle of the protractor was placed over the angle of curvature. Doppler ultrasonography was used to measure peak systolic velocity (PSV) and end-diastolic velocity (EDV). Stretched penile length and penile girth were also measured at this visit.
At a second visit 1 to 3 weeks after the initial (baseline) visit, the patients received PM-MSCs, which were injected intracavernosally. First, 1 mL of PM-MSCs was diluted with 2 mL of isotonic saline solution, to a total of 3 mL. Up to 2 mL of the diluted PM-MSC solution was then injected in and around the Peyronie plaques. The rest of the PM-MSC solution was then injected evenly into both corpora at the base at the base of the penis. No patient received additional PM-MSC injections after this visit during the course of the study.
Patient follow-up included visits for reevaluation 6 weeks, 3 months, and 6 months after the PM-MSC injections, with measurement of PSV, EDV, stretched penile girth, and angle of curvature. Plaque volume was calculated by multiplying plaque length by plaque width and height. Patients also filled out IIEF questionnaires before any injection at 6-week, 3-month, and 6-month visits.
Statistical analysis was performed, with differences considered statistically significant at P<.05. Two-tailed P values were calculated for all measured criteria, including PSV, EDV, stretched penile length, penile girth, and IIEF score. Plaque volumes were presented as raw data, and P values were not calculated for these measurements.