Evidence for increased glycodelin in leiomyoma and myometrial tissues

Abstract

Glycodelin, an angiogenic factor, is actively secreted by the luteal phase endometrium, decidua, and ovary. We have shown that glycodelin is increased in the serum and uterine flushings of women with leiomyoma. The objective of this study is to characterize glycodelin protein in leiomyoma and paired myometrial tissues as compared to normal myometrium. Prospective study. Leiomyoma and paired myometrial tissue from women with leiomyoma (n=18) and myometrial tissue from normal uteri (n=5) were obtained from normal ovulating women (21–46 years old). Approval for this protocol was granted by the Emory University IRB Committee. Tissues were placed in formol sucrose containing antioxidants (BHT). Sections were immunostained using avidin-biotin-alkaline phosphatase system. Sections were stained with 1:250 dilution of chicken anti-glycodelin peptide antibody and Von Willebrand Factor at 1:250 dilution in PBS containing 3% bovine serum albumin. For negative control, primary antibody was omitted. Rabbit anti-chicken immunoglobulin G (1:100) for anti-glycodelin peptide antibody and Von Willebrand Factor antibody (1:100) were used as secondary antibodies. Glycodelin peptide co-localized with Von Willebrand Factor Antibody that identifies endothelial cells. HSCORE was used to semi-quantify glycodelin. Leiomyoma (2.87±0.58) stains significantly higher for glycodelin than paired myometrium (2.42±0.38; P<0.021). Both leiomyoma and paired myometrium have significantly increased immunostaining when compared to normal myometrium (1.01±0.05; P<0.01). Statistical evaluation was performed by multi-way ANOVA and post hoc testing with the Bonferroni corrected T-test. Glycodelin protein is significantly increased in leiomyoma and paired myometrium of women with leiomyoma. We have previously shown that in leiomyoma and paired endometrium glycodelin also co-localizes with CD68 Antibody that identifies macrophage. Macrophages are increased in leiomyoma and paired myometrium and found diffusely scattered in muscle bundles as well as tissue septae. In normal myometrium macrophages are only found in tissue septae. The major difference in glycodelin staining can be explained by a significant increase in the vasculature of leiomyoma and paired myometrium vs. normal myometrium. Glycodelin has been shown to have an angiogenic role as it increases the release of VEGF protein and mRNA from multiple cancerous and non-cancerous cell lines (PNAS 2001;98:9265–70). The increase in vasculature seen in leiomyoma and myometrium may be, at least partly, explained by a significant increase in glycodelin. Angiogenesis is necessary for the growth of benign and malignant tumors, we speculate that glycodelin may be an important regulatory mediator of angiogenesis in leiomyoma.