Relationship between platelet-derived growth factor expression in leiomyomas and uterine volume changes after gonadotropin-releasing hormone agonist treatment

The unopposed estrogen effect is the main cause of leiomyoma growth and is at the basis of the clinical use of gonadotropin-releasing hormone (GnRH) agonists. Platelet-derived growth factor (PDGF) has been indicated as the main growth factor involved, in vitro in the proliferation response of leiomyoma smooth muscle cells to estrogen stimulation. The aim of this article is to evaluate the mitogenic action of PDGF in vivo by studying the relationship between PDGF expression in leiomyomas and post-GnRH analogue treatment changes in uterine volume. Thirty-nine patients suffering from uterine leiomyomas were treated with leuprorelin acetate depot 3.75 mg for three cycles; 31 untreated patients were enrolled as control group. Uterine volume was determined twice by ultrasonography in each patient, the first time at admission and the second time after treatment in the study group and after 3 months in the control group. The change in the uterine volume was then evaluated. Patients underwent surgery, and PDGF immunohistochemical detection was performed on the obtained fibroid samples. Uterine volume decreased significantlyafter treatment, whereas just a poor modification was found in the controls. The decrease in the uterine volume was found to be statistically related to PDGF expression. Thus PDGF levels decreased in treated patients as compared with controls. The decreased PDGF production in leiomyomas after GnRH analogue treatment and the relationship between decreased PDGF expression and greater shrinkage in uterine volume suggest that PDGF might have a mitogenic action on leiomyomas in vivo. Copyright 2002, Elsevier Science (USA). All rights reserved.