Tsutomu Nakahara

Inhibitors of VEGF signaling can block angiogenesis and reduce tumor vascularity, but little is known about the reversibility of these changes after treatment ends. In the present study, regrowth of blood vessels in spontaneous RIP-Tag2 tumors and implanted Lewis lung carcinomas in mice was assessed after inhibition of VEGF receptor signaling by AG-013736 or AG-028262 for 7 days. Both agents caused loss of 50%-60% of tumor vasculature. Empty sleeves of basement membrane were left behind. Pericytes also survived but had less alpha-SMA immunoreactivity. One day after drug withdrawal, endothelial sprouts grew into empty sleeves of basement membrane. Vessel patency and connection to the bloodstream followed close behind. By 7 days, tumors were fully revascularized, and the pericyte phenotype returned to baseline. Importantly, the regrown vasculature regressed as much during a second treatment as it did in the first. Inhibition of MMPs or targeting of type IV collagen cryptic sites by antibody HUIV26 did not eliminate the sleeves or slow revascularization. These results suggest that empty sleeves of basement membrane and accompanying pericytes provide a scaffold for rapid revascularization of tumors after removal of anti-VEGF therapy and highlight their importance as potential targets in cancer therapy.

The morphology and proportion of inner cell mass (ICM) of bovine blastocysts cultured in vitro or in vivo in rabbit oviducts after in-vitro fertilization of in-vitro matured follicular oocytes were compared with those of blastocysts fertilized in vivo by a differential fluorochrome staining technique. The delineation of each ICM cell was improved by the transfer of embryos derived from in-vitro fertilization to a rabbit oviduct although the cell-cell contacts of ICM cells were not as tight as those from in-vivo fertilization. The proportions (15.8 and 14.9%) of ICM in blastocysts cultured in vitro at early and expanded stages were significantly lower than those cultured in rabbit oviducts after in-vitro fertilization and fertilized in vivo. These results show that the transfer of bovine embryos derived from in-vitro fertilization to the rabbit oviduct increased the proliferation of ICM cells to the level of embryos fertilized in vivo although the cell-cell contact of ICM cell is not improved by the process.

BACKGROUND To assess the impact of ovarian cystectomy for endometriomas on the ovarian reserve, we evaluated the pre- and post-operative levels of serum anti-Müllerian hormone (AMH). We also analyzed the correlations between factors related to endometriosis and surgery for endometriomas and the serum AMH levels to investigate which factors affect ovarian reserve. METHODS Thirty-eight patients who were undergoing ovarian cystectomy for unilateral endometrioma (n = 20) and bilateral endometriomas (n = 18) participated. Preoperative and post-operative serum samples were collected and assayed for AMH levels, and changes between the two samples were analyzed in association with parameters of endometriosis and surgery for endometriomas. RESULTS The mean AMH level was 3.9 ng/ml prior to surgery, and was reduced to 2.1 ng/ml at 1 month post-surgery. The rate of decline of the serum AMH level was significantly higher in the bilateral group than the unilateral group (62.8 ± 29.6 versus 24.7 ± 32.5%, P < 0.001). The rate of decline in the serum AMH levels showed a significant correlation to the revised American Society for Reproductive Medicine (rASRM) score (P = 0.003), but not age, cyst diameter, blood loss during the operation or the number of follicles removed in the specimens. CONCLUSIONS Our results suggest that the decrease in ovarian reserve should be taken into account in patients indicated for cystectomy for bilateral endometriomas or unilateral endometrioma with high rASRM scores.