Assessment of folliculogenesis in ovarian tissue from young patients with Turner syndrome using a murine xenograft model.

OBJECTIVE: To study the impact of aneuploid granulosa and stromal cells on folliculogenesis of small ovarian follicles from patients with mosaic Turner syndrome (TS) using a murine xenograft model. DESIGN: Laboratory study. SETTING: University hospital. PATIENT(S): Ovarian cortical tissue was obtained by laparoscopic surgery from 18 patients with mosaic TS (aged 5-19 years) and 13 controls (aged 5-18 years). INTERVENTION(S): Part of each tissue fragment was used to karyotype ovarian cells in nongrafted tissue by fluorescence in situ hybridization. The remaining tissue was xenografted to severe combined immunodeficient mice for 5 months. Grafted tissue was analyzed for aneuploidy, and follicle density and morphology were determined. Expressions of proliferating cell nuclear antigen and anti-Müllerian hormone were investigated by immunohistochemistry. MAIN OUTCOME MEASURE(S): The impact of aneuploid granulosa and stromal cells on folliculogenesis. Fluorescence in situ hybridization of ovarian tissue before grafting was performed to determine the level of aneuploidy in stromal cells and oocytes and granulosa of small follicles. After xenografting, the level of aneuploidy of the newly formed layers of granulosa cells was again determined in secondary and antral follicles. RESULT(S): Follicle density in ovarian tissue from patients with TS was significantly lower than in controls before grafting. Fluorescence in situ hybridization analysis confirmed that 101 of 104 oocytes from nongrafted tissue of patients with TS showed normal X chromosome content, whereas granulosa and stromal cells were mainly 45,X. Fragments from 12 patients with TS contained follicles at all stages after xenografting, including secondary and antral follicles. Follicle density in patients with TS and controls decreased significantly after grafting. Moreover, a shift from high to low proportions of 45,X granulosa cells was observed during folliculogenesis. Expression of proliferating cell nuclear antigen in follicles from patients with TS increased significantly during grafting. Secretion of anti-Müllerian hormone was impaired before grafting in peripubertal/postpubertal girls with TS, but recovered after grafting. CONCLUSION(S): Our study showed that small follicles from patients with mosaic TS undergoes folliculogenesis, despite the presence of aneuploid granulosa and stromal cells. Ovarian tissue cryopreservation could therefore be a valid option to preserve fertility in young patients with mosaic TS if sufficient numbers of follicles are present, thus preferably before the age of 12.

The pivotal role of pituitary adenylate cyclase-activating polypeptide for lactate production and secretion in astrocytes during fear memory.

BACKGROUND: Pituitary adenylate cyclase-activating polypeptide (PACAP) plays an essential role in the modulation of astrocyte functions. Although lactate secretion from astrocytes contributes to many forms of neuronal plasticity in the central nervous system, including fear learning and memory, the role of PACAP in lactate secretion from astrocytes is unclear. METHODS: The amygdala and hippocampus of PACAP (+ / +) and PACAP (-/-) mice were acquired 1 h after memory acquisition and recall in the passive avoidance test. The concentration of glycogen and lactate in these regions was measured. The concentration of lactate in the hippocampus's extracellular fluid was also measured by microdialysis during memory acquisition or intracerebroventricular administration of PACAP. RESULTS: We observed that memory acquisition caused a significant decrease in glycogen concentration and increased lactate concentration in the PACAP (+ / +) mice's hippocampus. However, memory acquisition did not increase in the lactate concentration in PACAP (-/-) mice's hippocampus. Further, memory retrieval evoked lactate production in the amygdala and the hippocampus of PACAP (+ / +) mice. Still, there was no significant increase in lactate concentration in the same regions of PACAP (-/-) mice. In vivo microdialysis in rats revealed that the hippocampus's extracellular lactate concentration increased after a single PACAP intracerebroventricular injection. Additionally, the hippocampus's extracellular lactate concentration increased with the memory acquisition in PACAP (+ / +) mice, but not in PACAP (-/-) mice. CONCLUSIONS: PACAP may enhance lactate production and secretion in astrocytes during the acquisition and recall of fear memories.