Basal lamina characterization in frozen-thawed and long-term grafted human prepubertal ovarian tissue.

RESEARCH QUESTION: Are there differences in the composition and structure of the basal lamina surrounding follicles in prepubertal versus adult human ovarian tissue? DESIGN: Frozen-thawed human ovarian tissue from six prepubertal and seven adult patients was divided into three fragments in each case: two for non-grafted tissue evaluation and one for long-term xenografting to mice. Collagen IV and laminin expression were investigated by immunohistochemistry before and after grafting. The basal lamina was analysed by transmission electron microscopy on frozen-thawed tissue. RESULTS: In frozen-thawed tissue, collagen IV was significantly less expressed around prepubertal follicles than around adult follicles (primordial, P = 0.02; intermediate/growing follicles, P = 0.03), while laminin was significantly more expressed (primordial, P = 0.03; intermediate, P = 0.01). Collagen IV expression was significantly higher around prepubertal primordial follicles in grafted tissue than in non-grafted tissue, reaching similar levels to those in adult tissue. Ultrastructure analysis showed the basal lamina around follicles in prepubertal frozen-thawed tissue to be rather patchy and thinner than around adult follicles (primordial/intermediate, P = 0.001; primary, P = 0.02). CONCLUSIONS: In frozen-thawed tissue, the basal lamina around prepubertal follicles is less mature than around adult follicles, but it becomes similar in both prepubertal and adult subjects after grafting. Grafting could therefore induce maturation of the basal lamina around prepubertal follicles.

Follicle populations and vascularization in ovarian tissue of pediatric patients before and after long-term grafting.

OBJECTIVE: To characterize ovarian tissue from pediatric patients by evaluating development and vascularization in follicle populations and comparing it with adult tissue after xenografting. DESIGN: Prospective experimental study. SETTING: Academic research center. PATIENT(S): Five children (median age 3 years) and seven women (median age 28 years). INTERVENTION(S): Hematoxylin and eosin staining, immunofluorescence, and transmission electron microscopy (TEM) evaluation before and after grafting. MAIN OUTCOME MEASURE(S): Follicle density, morphology, classification, and size, ovarian tissue vascularization, follicle ultrastructure. RESULT(S): Frozen-thawed ovarian tissue was divided into three fragments: nongrafted controls, TEM, and xenografting for 20 weeks. Follicle density was statistically significantly higher in pediatric than adult patients; even though it decreased in both groups after transplantation, it remained higher in pediatric patients. In the pediatric group, quiescent-stage follicles were the majority of the follicle pool before and after grafting, while growing follicles statistically significantly increased in both groups after grafting. Abnormal and atretic follicles were also observed in pediatric tissue and declined with age and after grafting. Pediatric ovarian tissue contained more and larger immature vessels, while mature vessels were larger in adults. The TEM analysis of abnormal pediatric follicles showed loss of shape and vacuolization of the cytoplasm without organelle damage. CONCLUSION(S): Statistically significant differences in follicle density were observed between pediatric and adult patients, but the follicle proportions were similar before and after grafting, with the exception of atretic and abnormal follicles. Pediatric tissue contains more and larger immature vessels than adult tissue, and the posttransplantation revascularization process is accelerated in this group.