Sjerp M. Weima

FSH receptor genotype is associated with pregnancy but not with ovarian response in IVF

Two very common single nucleotide polymorphisms at positions 307 and 680 in exon 10 of the FSH receptor gene have been associated with ovarian response in IVF. This observational study evaluated the role of the FSH receptor genotype in the prediction of poor response and clinical pregnancy in IVF in comparison with other markers, such as age, basal FSH, anti-Müllerian hormone and antral follicle count. In addition, the in-vitro cAMP response towards recombinant FSH in cultured granulosa cells of patients with different FSH receptor genotypes was determined. A total of 105 IVF patients undergoing ovarian stimulation in a long suppression protocol were included in the study. The ovarian response was comparable between patients with different FSH receptor genotypes. Patients with polymorphism Ser/Ser had implantation and pregnancy rates that were three times higher compared with patients with polymorphism Asn/Asn. FSH receptor genotype was not associated with a poor response in IVF, but showed a positive association with pregnancy, independent of age. There was no difference in cAMP production in cultured granulosa cells of patients with different FSH receptor genotypes (n=62). It is concluded that FSH receptor genotype is associated with pregnancy in IVF, but not with ovarian response.

Identification of the type-B receptor for platelet-derived growth factor in human embryonal carcinoma cells

The human embryonal carcinoma (EC) cell line Tera 2 clone 13 (T2/13) can be induced to differentiate in vitro into neuroectodermal cell types with retinoic acid. Undifferentiated cells are characterized by rapid proliferation, whereas differentiated cells show a prolonged generation time, have a limited life span, and possess new cell-surface markers. In the present study we establish that both differentiated and undifferentiated T2/13 cells express the type-B platelet-derived growth factor (PDGF) receptor mRNA and bind PDGF-BB with high affinity. Differentiation causes a three-fold increase in receptor number per cell and leaves the affinity of the receptors unaffected. These data are the first to describe expression of this receptor in EC cells. The biosynthesis and degradation of this receptor were studied in undifferentiated as well as in differentiated T2/13 cells using an anti-type-B receptor antibody. These experiments revealed that high concentrations of recombinant PDGF-AA did not accelerate receptor metabolism in both cell types. In contrast, human PDGF or recombinant PDGF-BB added to the culture dishes readily increased receptor degradation. These results demonstrate that T2/13 cells express functional type-B PDGF receptors and suggest that cells responsive to PDGF might be present during mammalian development before the onset of mesoderm formation.

Human teratocarcinoma cells express functional insulin-like growth factor I receptors

Using iodinated insulin-like growth factors (IGFs) we have detected receptors for IGF-I at the cell surface of the clonally derived human embryonal carcinoma cell line Tera 2 clone 13. Affinity crosslinking of IGFs to Tera 2 clone 13-derived membrane preparations revealed the presence of proteins with features of both type-I and type-II IGF receptors. Treatment of Tera 2 clone 13 cells with retinoic acid to induce differentiation results in an increased number of cell surface receptors, apparently without altering the ratio of type-I and type-II receptors. In addition, Tera 2 clone 13 IGF-I receptors catalyze (auto)phosphorylation at tyrosine upon IGF-I and insulin binding. These findings suggest that type-I IGF receptors might be involved in mediating the effects of IGFs and insulin upon the proliferation of Tera 2 clone 13 cells.

The effect of colchicine treatment on spermatozoa: a cytogenetic approach.

Colchicine is an alkaloid which exerts its main effect at the cellular level by its interference with microtubule formation, thereby affecting mitosis and other microtubule-dependent functions (1). In routine cytogenetic diagnostics, colchicine is commonly used in in vitro culture systems to block spindle formation and arrest cells undergoing mitosis at the metaphase stage (2,3). On the other hand, due to its antiinflammatory effect, colchicine is used for the treatment of several diseases, including gouty arthritis (4), familial Mediterranean fever (FMF) (5), and Behcets disease (6). The effects of colchicine on sperm production and function in men are controversial. Recently, HaimovKochman and Ben-Chetrit (7) reviewed all papers published from 1966 to April 1997 regarding this effect in healthy individuals as well as in patients. The authors concluded that colchicine seems to have no significant direct adverse effect on sperm production and function as determined by routine sperm analysis. However, it is unknown whether the incidence of aneuploidy in spermatozoa of men treated with colchicine is affected, since colchicine can act directly on chromosomes by detaching chromosomes from the meiotic spindle. Recently, two infertile couples of which the male partners were treated with colchicine attended our in vitro fertilization (IVF) center. In both couples routine sperm analyses were performed and an additional ejaculate was prepared for cytogenetic analysis by three-color fluorescence in situ hybridization (FISH) with probes specific for chromosomes 18, X, and Y(8).