Dor J

BACKGROUND: Storing ovarian tissue for fertility preservation in cancer patients carries the risk of the presence of malignant cells that could lead to recurrence of cancer after reimplantation. Methods to exclude presence of cancer cells were used to improve the safety of cryopreservation-reimplantation procedures. METHODS: Fifty-eight patients with hematological malignancies were referred for the storage of ovarian tissue for fertility preservation. Investigation included preoperative imaging and histological evaluation of fresh ovarian tissue. After thawing markers to detect minimal residual disease (MRD) were used and compared with patient's disease used as positive control (five patients). RESULTS: Preoperative imaging detected disease in the ovaries (two patients). Conventional histology post-tissue harvesting did not disclose malignant cells (56 patients). MRD results post-thawing were negative in Hodgkin's disease (CD30 immunohistochemical staining), in T- and B-cell lymphoma (PCR for T-cell receptor and Ig clones, respectively) and in two chronic myelogenous leukemia patients (RT-PCR for BCR-ABL gene expression). However, highly sensitive real-time RT-PCR was positive in one CML patient and, this alarming result avoided tissue transplantation. CONCLUSIONS: Preoperative imaging prevented operations and storage of tissue with cancer. Evaluation of stored ovarian tissue for MRD using sensitive markers is essential to increase safety and to prevent reimplantation of tissue with malignant cells.

BACKGROUND: Chemotherapy destroys primordial follicles and can lead to ovarian atrophy. Although reports indicate that apoptosis is the mechanism responsible for follicle loss, additional pathways can be involved. This study investigates the damage in human ovaries after administration of non-sterilizing doses of chemotherapy. METHODS: In a blind study, pathological changes in ovarian tissue harvested for cryopreservation were evaluated. The study group comprised young non-sterile cancer patients, previously exposed to chemotherapy who were (mean +/- SD), when compared with non-exposed patients. RESULTS: Thirty-five cancer patients aged 28.7 +/- 6.74; 17 were previously exposed to non-sterilizing chemotherapy and 18 were not. In all samples, primordial follicles were present. In previously exposed patients, damage to cortical blood vessel and proliferation of small vessels was observed. The cortex showed focal areas of fibrosis with disappearance of follicles (sensitivity 76%, positive predictive value 75% for <37 years old patients). Older patients, not exposed to chemotherapy (5/7) showed similar pathological changes. CONCLUSIONS: Injury to blood vessels and focal ovarian cortical fibrosis are aspects of ovarian damage caused by chemotherapy. These findings indicate a potential additional mechanism of damage to the direct apoptotic effect of chemotherapy on follicles. The possibility that these changes are involved in ageing ovaries should be further investigated.

In humans, only a small fraction (2-12%) of a sperm population can respond by chemoattraction to follicular factors. This recent finding led to the hypothesis that chemotaxis provides a mechanism for selective recruitment of functionally mature spermatozoa (i.e., of capacitated spermatozoa, which possess the potential to undergo the acrosome reaction and fertilize the egg). This study aimed to examine this possibility. Capacitated spermatozoa were identified by their ability to undergo the acrosome reaction upon stimulation with phorbol 12-myristate 13-acetate. Under capacitating conditions, only a small portion (2-14%) of the spermatozoa were found to be capacitated. The spermatozoa were then separated according to their chemotactic activity, which resulted in a subpopulation enriched with chemotactically responsive spermatozoa and a subpopulation depleted of such spermatozoa. The level of capacitated spermatozoa in the former was approximately 13-fold higher than that in the latter. The capacitated state was temporary (50 min < life span < 240 min), and it was synchronous with the chemotactic activity. A continuous process of replacement of capacitated/chemotactic spermatozoa within a sperm population was observed. Spermatozoa that had stopped being capacitated did not become capacitated again, which indicates that the capacitated state is acquired only once in a sperm's lifetime. A total sperm population depleted of capacitated spermatozoa stopped being chemotactic. When capacitated spermatozoa reappeared, chemotactic activity was restored. These observations suggest that spermatozoa acquire their chemotactic responsiveness as part of the capacitation process and lose this responsiveness when the capacitated state is terminated. We suggest that the role of sperm chemotaxis in sperm-egg interaction in vivo may indeed be selective recruitment of capacitated spermatozoa for fertilizing the egg.

Spermatozoa normally encounter the egg at the fertilization site (in the Fallopian tube) within 24 hr after ovulation. A considerable fraction of the spermatozoa ejaculated into the female reproductive tract of mammals remains motionless in storage sites until ovulation, when the spermatozoa resume maximal motility and reach the fertilization site within minutes. The nature of the signal for sperm movement is not known, but one possible mechanism is attraction of spermatozoa to a factor(s) released from the egg. We have obtained evidence in favor of such a possibility by showing that human spermatozoa accumulate in follicular fluid in vitro. This accumulation into follicular fluid was higher by 30-260% than that observed with buffer alone and was highly significant (P less than 10(-8)). Not all of the follicular fluids caused sperm accumulation; however, there was a remarkably strong correlation (P less than 0.0001) between the ability of follicular fluid from a particular follicle to cause sperm accumulation and the ability of the egg, obtained from the same follicle, to be fertilized. These findings suggest that attraction may be a key event in the fertilization process and may give an insight into the mechanism underlying early egg-sperm communication.

The efficiency of elective cervical suture in preventing premature delivery thus reducing neonatal mortality was studied in a group of 50 twin pregnancies. All pregnancies occurred after induction of ovulation and twins were diagnosed early by ultrasound. 25 randomly selected patients underwent elective cervical suture. 22 sutured and 23 non-sutured patients were followed until delivery, while 5 patients aborted in the second trimester. The benefit of suturing on the duration of pregnancy and its outcome were assessed. Of the sutured patients, 10 (45.4%) delivered prematurely and the neonatal death rate was 18.2%. In the non-sutured patients, 11 (47.8%) delivered prematurely and the neonatal death rate was 15.2%. This study demonstrates that elective cervical suture was not effective in prolonging gestation or improving fetal outcome in twin pregnancies following induced ovulation.