Decreased Expression of Angiogenin in the Eutopic Endometrium from Women with Advanced Stage Endometriosis

Angiogenin, a potent inducer of angiogenesis, is expressed in human endometrium. This study was performed to compare the expression of angiogenin mRNA level in the eutopic endometrium from women with and without endometriosis. Thirty-two women with advanced stage endometriosis and 29 control women were recruited. Following isolation of total RNA from endometrial tissue and reverse transcription, cDNA samples were amplified by real time polymerase chain reaction to quantify the expression of angiogenin genes. In selected patients, immunohistochemical staining was utilized to localize the area of angiogenin expression. Angiogenin mRNA level was significantly lower in the endometriosis group than in the control group during the secretory phase, especially the mid-secretory phase, and the decline was observed mainly in the women who presented with infertility. Within the endometriosis group, angiogenin mRNA levels did not differ between the proliferative and secretory phases, but, in the control group, the level in the secretory phase was higher than that during the proliferative phase. Immunohistochemistry showed that the glandular epithelial cell layer was decorated positively in both groups. These findings suggest that the relative deficiency of angiogenin expression in the secretory endometrium could impair implantation in women with advanced stage endometriosis.

A novel way of therapeutic angiogenesis using an adeno-associated virus-mediated angiogenin gene transfer

To develop a novel therapeutic angiogenesis for the treatment of cardiovascular diseases, angiogenin (ANG1) was examined as a potential therapeutic gene. An adeno-associated virus (AAV)-mediated gene delivery system was used to measure the therapeutic efficacy of ANG1. Using a triple co-transfection technique, rAAV-ANG1-GFP, rAAV- VEGF-GFP and rAAV-GFP vectors were produced, which were then used to infect human umbilical vein endothelial cells (HUVECs) in order to evaluate in vitro angiogenic activities. Their protein expressions, tagged with green fluorescent protein (GFP), were monitored by confocal microscopy. The functional activities were measured using wound-healing HUVEC migration assays. The number of migrated cells stimulated by both the expressed ANG1 and the VEGF in rAAV-infected HUVECs increased almost twice the number observed in the expressed GFP control. In vivo angiogenic activities of the expressed ANG1 or VEGF were determined using mouse angiogenesis assays. The angiogenic activities of ANG1 or VEGF expressed in the injected mice were increased by 1.36 and 2.16 times, respectively, compared to those of the expressed GFP control. These results demonstrate that the expressed ANG1 derived from rAAV infection has in vitro and in vivo angiogenic activities and suggest that the rAAV-ANG1 vector is a potential strategy for therapeutic angiogenesis.