Significance of matrix metalloproteinases in the pathophysiology of the ovary and uterus.

Matrix metalloproteinases (MMP) are capable of degrading a variety of extracellular matrix (ECM) proteins and are also involved in the processing of a number of bioactive molecules. Our findings indicate that the functions of MMP in the ovary and uterus are organ-specific and time-dependently vary during the reproductive cycle. Prolactin induces structural luteolysis indicated by loss of luteal weight, protein and DNA within 36 h after pretreatment with ergot alkaloid. MMP activation appears crucial for the selective depletion of protein during luteal involution, which entails loss of ECM accompanied by apoptosis. During GnRHagonist-induced luteolysis, this response was also associated with marked increases in MMP-2, which degraded collagen type IV, and MT1-MMP, which in addition to activating MMP-2 also degrades collagen type I, III and V. We also found that the level of MT1-MMP and MMP-2 expression in the human CL is greater during the late luteal phase than during either the early mid luteal phases or during gestation, respectively. That dehydroepiandrosterone (DHEA) treatment caused the formation of cysts from antral follicles in the ovaries of immature rats while depressing MMP-2 collagenolytic activity and enhancing lysyl oxidase expression highlights the importance of collagen degradation in the process of ovulation and suggests that changes in the activities of these enzymes play a key role in ovarian cystogenesis in polycystic ovary syndrome patients. Furthermore, immunohistochemical analyses showed that MT1-MMP and FasL co-localize with TdT-mediated dUTP-biotin nick end-labeling (TUNEL)-positive apoptotic granulosa cells in rats treated with DHEA, that the Fas/FasL/Caspase-8 (death receptor-dependent) pathway is pivotal for follicular atresia and that increased levels of MT1-MMP likely play an important role in tissue remodeling during follicular atresia. After parturition, the uterus undergoes involution, a conspicuous feature characterized by a rapid reduction in the collagen content mediated by degradation of extracellular collagen bundles. Our findings strongly suggest that MT1-MMP, MMP-2 and MMP-9 are each time-dependently regulated and play important roles in tissue remodeling during postpartum uterine involution. (Reprod Med Biol 2006; 5: 235-243).

Identical changes in Bax expression, but not Fas ligand expression, occur in structural luteolysis in gonadotropin releasing hormone agonist- and prolactin-treated superovulated rats.

Structural luteolysis induced by gonadotropin releasing hormone agonist (GnRHa) or prolactin (PRL) is defined as histological involution of the corpus luteum. We reported that one of the mechanisms of structural luteolysis induced by PRL was tissue remodeling by matrix metalloproteinase (MMP) and also apoptosis in superovulated rats. We also reported that GnRHa induced structural luteolysis with elevation of MMP. In this study, we investigated whether GnRHa caused apoptosis in mature corpus luteum of superovulated rats and also examined the expression of apoptosis-related molecules (Fas, Fas ligand (FasL), Bcl-2, Bax). We gave 4-day GnRHa treatment 5 days after hCG injection to immature female rats treated with pregnant mare surum gonadotrophin (PMSG) and hCG to induce structural involution of mature corpus luteum. PMSG-hCG-treated rats without GnRHa treatment, rats treated with bromocryptine (Brom) to induce functional luteolysis and rats treated with Brom followed by PRL (Brom+PRL) to mimic the PRL surge to induce structural luteolysis as we previously reported were used for comparison. GnRHa treatment caused structural luteolysis characterized by structural involution, a decrease in the serum progestin level, and apoptotic bodies as well as structural luteolysis induced by Brom+PRL. FasL expression in corpora lutea was elevated after Brom treatment, but there was no elevation of FasL after GnRHa treatment started. FasL expression decreased and Bax expression increased in structural luteolysis induced by GnRHa as well as Brom+PRL treatment, although Fas and Bcl-2 expression did not change throughout the luteal phase. In summary, both GnRHa and Brom+PRL caused structural luteolysis, one of whose mechanisms was apoptosis with an increase in Bax expression, but not with an identical change in FasL expression. It is speculated that the significance in alteration of FasL may involve some mechanism other than apoptosis.

[A pilot study of combined chemotherapy with paclitaxel, doxorubicin and cisplatin for endometrial cancer].

A pilot trial of combined chemotherapy with paclitaxel, doxorubicin and cisplatin was conducted in patients with advanced endometrial cancer. Between June 2000 and March 2002 8 patients were treated with combined chemotherapy, consisting of paclitaxel, 135 mg/m2; doxorubicin, 30 mg/m2; and cisplatin, 50 mg/m2 (TAP therapy). Patients received 3 to 5 courses of TAP therapy every 4 weeks. The major adverse effect was myelosuppression. All patients had grade 3 or 4 neutropenia, but did not have any severe infection with uncontrollable fever. Only 1 patient discontinued additional therapy due to grade 3 thrombocytopenia after 3 cycles. Grade 2 neurotoxicity occurred in 5 patients, but grade 3 was not observed. Among 5 patients with measurable tumors, 4 achieved partial response and 1 had no change of tumor size, indicating a response rate of 80.0%. We found that TAP therapy was feasible with G-CSF support and shows potential for high efficacy in advanced endometrial cancer.

Continuation of GnRH agonist administration for 1 week, after hCG injection, prevents ovarian hyperstimulation syndrome following elective cryopreservation of all pronucleate embryos.

BACKGROUND: An approach consisting of elective cryopreservation of all embryos has been proposed for patients at risk of ovarian hyperstimulation syndrome (OHSS). Although elective cryopreservation can prevent pregnancy-induced late OHSS, it cannot prevent early OHSS. Early OHSS is reported to have been complicated with thromboembolism. The study was carried out to assess the efficacy with which the continued administration of GnRH agonist for 1 week after 5000 IU of hCG injection could prevent early OHSS. METHODS: This study employed an open controlled clinical trial at three centres for treatment of infertility in Sapporo. A total of 138 patients at risk of OHSS during IVF-embryo transfer from January 1, 1998 to December 31, 1999, were assigned in turn either to a group with elective cryopreservation of all pronucleate embryos (n = 68) or to one with continuation of GnRH agonist administration for 1 week after hCG injection following elective cryopreservation (n = 70). Subsequently, they were transferred in hormone replacement cycles. The development of severe OHSS (ascites, haemoconcentration) was compared between the two groups. RESULTS: A total of 10% of patients developed severe OHSS necessitating hospitalization because of a marked increase in ascites in the upper abdomen and the haemoconcentration in the elective cryopreservation alone group. On the other hand, none developed severe OHSS in the GnRH agonist continuation group. CONCLUSIONS: In our study, continuation of GnRH agonist for 1 week after hCG injection prevented severe early OHSS following elective cryopreservation of all embryos. This treatment is safe and cost-beneficial, and should be performed promptly for patients at risk of OHSS.