Amyloidogenic and Neuroinflammatory Molecular Pathways Are Contrasted Using Menaquinone 4 (MK4) and Reduced Menaquinone 7 (MK7R) in Association with Increased DNA Methylation in SK-N-BE Neuroblastoma Cell Line

Besides its role in coagulation, vitamin K seems to be involved in various other mechanisms, including inflammation and age-related diseases, also at the level of gene expression. This work examined the roles of two vitamin K2 (menaquinones) vitamers, namely, menaquinone-4 (MK4) and reduced menaquinone-7 (MK7R), as gene modulator compounds, as well as their potential role in the epigenetic regulation of genes involved in amyloidogenesis and neuroinflammation. The SK-N-BE human neuroblastoma cells provided a "first-line" model for screening the neuroinflammatory and neurodegenerative molecular pathways. MK7R, being a new vitamin K form, was first tested in terms of solubilization, uptake and cell viability, together with MK4 as an endogenous control. We assessed the expression of key factors in amyloidogenesis and neuroinflammation, observing that the MK7R treatment was associated with the downregulation of neurodegeneration- (PSEN1 and BACE1) and neuroinflammation- (IL-1β and IL-6) associated genes, whereas genes retaining protective roles toward amiloidogenesis were upregulated (ADAM10 and ADAM17). By profiling the DNA methylation patterns of genes known to be epigenetically regulated, we observed a correlation between hypermethylation and the downregulation of PSEN1, IL-1β and IL-6. These results suggest a possible role of MK7R in the treatment of cognitive impairment, giving a possible base for further preclinical experiments in animal models of neurodegenerative disease.

Adjusting the dose to the individual response of the patient during the induction of ovulation with pulsatile gonadotropin-releasing hormone

To identify the effective dose of intravenous pulsatile gonadotropin-releasing hormone necessary to induce ovulation in patients with chronic anovulation of diverse etiology, 40 women were subdivided into four groups: idiopathic hypogonadotropic hypogonadism (IHH), functional hypothalamic amenorrhea, normoandrogenic oligomenorrhea, and polycystic ovarian syndrome (PCOS). During 90 treatment cycles, the dose was the only parameter that was progressively adjusted. The overall ovulation rate per cycle was 100% in IHH, functional hypothalamic amenorrhea, and normoandrogenic oligomenorrhea, using only 5 micrograms/90 minutes in functional hypothalamic amenorrhea and normoandrogenic oligomenorrhea and up to 7.5 micrograms/90 minutes in IHH. In PCOS, the ovulation rate was 67.6%, using up to 20 micrograms/90 minutes. The lesser degree of effectiveness observed in PCOS can probably be explained by the different basal endocrine profile presented by these subjects.

Repeated transient hypergonadotropic amenorrhea during pharmacologic induction of multiple follicular development with exogenous gonadotropins

Human gonadotropins are widely used for induction of ovulation in the treatment of anovulatory infertility and for induction of multiple follicular development (MFD) in in vitro fertilization (IVF), gamete intrafallopian transfer (GIFT), and artificial insemination with husband's semen (AIH) programs. Reported is a patient with normal menstrual cycles, who had two episodes of gonadal unresponsiveness to human gonadotropin therapy, followed by transient hypergonadotropic amenorrhea ("resistant ovary" syndrome), during induction of MFD in conjunction with AIH as treatment for unexplained infertility. The first episode occurred during the sixth cycle of a first series of MFD induction with daily intramuscular injections of exogenous gonadotropins. The second episode occurred during the second cycle of a second series of MFD induction with intravenous pulsatile administration of FSH. On both occasions, normalization of endogenous gonadotropin levels and reappearance of ovulatory cycles occurred spontaneously, after two and three months, respectively. A similar mechanism could occur in the failures of MFD induction observed in IVF programs.

Dexamethasone reduces the postcastration gonadotropin rise in women

To investigate the influence of glucocorticoids on gonadotropin release in humans, we studied the effects of dexamethasone (DXM) administration on basal and GnRH-stimulated gonadotropin secretion in normal women after bilateral ovariectomy (OVR). From the 7th to the 14th day after OVR, 9 women received DXM (2.25 mg/day) and 13 women received placebo (control women). Plasma FSH and LH concentrations were measured before OVR and daily from the 7th to the 14th day after surgery. In addition, the FSH and LH responses to exogenous GnRH (10 micrograms, iv bolus dose) were determined in all DXM-treated women and in 5 control women on the 7th and 14th days after surgery. Plasma gonadotropin levels increased similarly in all women on the 7th day after OVR. DXM administration significantly limited (P less than 0.001) the progressive rise of basal LH and FSH levels from days 7 to 14. DXM treatment also blunted (P less than 0.005) the OVR-induced increase in the responsiveness of both LH and FSH to exogenous GnRH. These findings suggest that glucocorticoids inhibit the secretion of both gonadotropins at the pituitary level in ovariectomized women.

Prolactin-releasing action of a low dose of exogenous gonadotropin-releasing hormone throughout the human menstrual cycle

Pharmacological doses of gonadotropin-releasing hormone (GnRH) are known to induce prolactin (PRL) release in different pathological states. The same effect can be observed in postmenopausal women and during the phases of menstrual cycle characterized by high estrogen levels. With the aim to evaluate whether nonpharmacological doses of GnRH are also able to induce PRL release, gonadotropin and PRL response to a low dose of GnRH (10 micrograms, i.v. bolus) was evaluated in 70 normal women during different phases of their menstrual cycle. A significant PRL increase was observed in 33% of subjects during the first days of the cycle (menstrual phase; days 1-3 from the beginning of menstrual bleeding: n = 6), in 24% of subjects during early follicular phase (days -10 to -8 from LH peak: n = 17); in 38% of subjects during midfollicular phase (days -6 to -4 from LH peak: n = 8); in 78% of subjects during preovulatory phase (days -2 to -1 from LH peak; n = 9); in 67% of subjects during postovulatory phase (days +1 to +2 from LH peak; n = 6) and in 42% of subjects during midluteal phase (days +5 to +8 from LH peak; n = 24). In brief, the increase of mean PRL levels after GnRH administration was only significant (p less than 0.05) during pre- and postovulatory phases. The percentage of patients who showed a PRL response during the different phases of menstrual cycle was significantly correlated to the mean maximal net increase of LH (r = 0.927; p less than 0.01) and to the mean maximal net increase of FSH (r = 0.926; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)