Bioactivity and Pharmacodynamics of X002, a Follicle-stimulating Hormone-IgG4 Fc Fusion Protein

Current follicle-stimulating hormone (FSH) drugs meet safety criteria but have suboptimal efficacy, poor patient compliance, and high cost. Alternative FSH-like drugs would help to meet the high market demand. Here, we evaluated X002, an FSH-Fc fusion protein, for bioactivity and half-life in vitro and in vivo. In all cases, the effects of X002 were compared with those of a commercially available short-acting FSH recombinant hormone. First, female Kunming mice (age, 21 to 24 d) were stimulated with pregnant mare serum gonadotropin (PMSG) for 46 h, after which naked oocytes were harvested, treated with X002 or the comparison agent at 37 °C for 4 h, and then evaluated for germinal vesicle breakdown. Second, cumulus-oocyte complexes (COC) were collected from PMSG-stimulated mice and cocultured with X002 or the comparison agent for 14 h; the COC diameters were then measured, and the expression of genes involved in COC expansion were evaluated using quantitative RT-PCR analysis. Third, to assess the pharmacokinetics of X002, female Sprague-Dawley rats (age, 6 to 8 wk) were injected subcutaneously with X002 or the comparison agent; serum samples then were collected at various times and assessed via ELISA. Fourth, to evaluate X002 pharmacodynamics, 26-d-old female Sprague-Dawley rats were treated with X002 or the comparison agent; 84 h later, the rats were stimulated with human chorionic gonadotropin (hCG). At 12 h after hCG injection, euthanasia was performed. Ovaries were removed and weighed, and serum levels of estradiol and progesterone were measured. Finally, to assess superovulation, the oocytes in the fallopian tubes were counted at 108 h after in vivo treatment of rats with X002 or the comparison agent. The data show that X002, a long-acting agent, promoted germinal vesicle breakdown and COC expansion in vitro and in vivo ovarian weight gain and superovulation to a degree similar to the short-acting comparison agent.

Effect of Prepregnancy Obesity on Litter Size in Primiparous Minipigs

Obesity is a public health problem in both developed and developing countries, and the negative effects of obesity on reproductive physiology have been highlighted recently. We evaluated the effects of porcine obesity index, sex hormones, and peptide hormones on litter size in various breeds of minipigs. Blood samples were collected from sedated 8-,10-, and 12-mo-old minipigs to measure preovulatory levels of sex hormones (follicle-stimulating hormone, luteinizing hormone, estradiol, progesterone, testosterone, and prolactin) and peptide hormones (insulin-like growth factor, glucagon, cortisol, growth hormone, free thyroxine, free triiodothyronine, insulin, and leptin). We also measured weight, abdominal circumference, neck circumference, and body length and then calculated the porcine obesity index. Data were analyzed by one-way ANOVA, and means were compared by least significance difference testing. Pearson correlation between parameters and litter size was analyzed. Prepregnancy porcine obesity index and litter size were negatively correlated in primiparous minipigs. Litter size was influenced by luteinizing hormone, estradiol, progesterone, testosterone, prolactin, follicle-stimulating hormone, cortisol, insulin-like growth factor 1, growth hormone, free thyroxine, insulin, and leptin. In conclusion, prepregnancy obesity reduces litter size in primiparous minipigs.

Effects of diet-induced obesity on metabolic parameters and reproductive function in female Ossabaw minipigs

This study characterizes the effect of an excess-calorie, high-fat, high-cholesterol, high-fructose diet on metabolic parameters and reproductive function in female Ossabaw minipigs. Cycling sows were fed a hypercaloric, high-fat, high-cholesterol, and high-fructose diet (obese, n = 4) or a control diet (control, n = 5) for 13 mo. During the final 4 mo, ovarian ultrasonography was done, blood was collected, and weights and measures were taken. Pigs then underwent ovarian stimulation. Cycle length and androstenedione, total testosterone, progesterone, estradiol, follicle-stimulating hormone, luteinizing hormone, insulin, fructosamine, lipid, and glucose levels were measured. In addition, adipose tissue aromatase gene expression was assessed. As compared with control pigs, obese pigs were hyperglycemic and hyperinsulinemic; had elevated total cholesterol, triglyceride, and leptin levels, and demonstrated abdominal adiposity. Visceral adipose tissue of obese pigs, as compared with control pigs, showed increased aromatase gene expression. Obese pigs had longer estrous cycles, higher serum androstenedione, and higher luteal phase serum luteinizing hormone, compared with control pigs. During the luteal phase, obese pigs had more medium, ovulatory, and cystic ovarian follicles, whereas control pigs had more small ovarian follicles. When fed an excess-calorie, high-fat, high-cholesterol, high-fructose diet, female Ossabaw minipigs develop obesity, metabolic syndrome, and abnormal reproductive function. This animal model may be applicable to studies of the effects of obesity on fertility in women.

Characterization of ovarian aging and reproductive senescence in vervet monkeys (Chlorocebus aethiops sabaeus)

Female vervet monkeys (Chlorocebus aethiops sabaeus) are used as an experimental model for chronic diseases relevant to women's health. However, reproductive senescence (menopause) has not yet been characterized for vervet monkeys. Here we describe the histologic, hormonal, and menstrual markers of reproductive senescence in vervet monkeys from the Wake Forest Vervet Research Colony. Ovaries from monkeys (age, 0 to 27 y) were serially sectioned (5 μm), stained, and photographed. In every 100th section, the numbers of primordial, primary, and secondary follicles were determined, and triplicate measurements were used to calculate mean numbers of follicles per ovary. Antimüllerian hormone (AMH), follicle stimulating hormone, and menstrual cycle length were measured in additional monkeys. Primordial follicles and AMH decreased significantly with age, and significant correlations between numbers of primordial and primary follicles and between numbers of primary and secondary follicles were noted. Histologic evaluation revealed that ovaries from 4 aged monkeys (older than 23 y) were senescent. One aged monkey transitioned to menopause, experiencing cycle irregularity over 4 y, eventual cessation of menses, and plasma AMH below the level of detection. Finally, with increasing age, the percentage of female vervets with offspring declined significantly. The present study provides insight into ovarian aging and reproductive senescence in vervet monkeys. Results highlight the importance of considering this nonhuman primate as a model to investigate the relationships between ovarian aging and chronic disease risk.

Modeling perimenopause in Sprague-Dawley rats by chemical manipulation of the transition to ovarian failure

Various age-related diseases increase in incidence during perimenopause. However, our understanding of the effects of aging compared with hormonal changes of perimenopause in mediating these disease risks is incomplete, in part due to the lack of an experimental perimenopause model. We therefore aimed to determine whether manipulation of the transition to ovarian failure in rats via the use of 4-vinylcyclohexene diepoxide (VCD) could be used to model and accelerate hormonal changes characteristic of perimenopause. We examined long-term (11 to 20 mo), dose-dependent effects of VCD on reproductive function in 1- and 3-mo-old female Sprague-Dawley rats. Twenty-five daily doses of VCD (80 or 160 mg/kg daily compared with vehicle alone) depleted ovarian follicles in a dose-dependent fashion in rats of both ages, accelerated the onset of acyclicity, and caused dose-dependent increases in follicle-stimulating hormone that exceeded those naturally occurring with age in control rats but left serum levels of 17β-estradiol unchanged, with continued ovarian production of androstenedione. High-dose VCD caused considerable nonovarian toxicities in 3-mo-old Sprague-Dawley rats, making this an unsuitable model. In contrast, 1-mo-old rats had more robust dose-dependent increases in follicle-stimulating hormone without evidence of systemic toxicity in response to either VCD dose. Because perimenopause is characterized by an increase in follicle-stimulating hormone with continued secretion of ovarian steroids, VCD acceleration of an analogous hormonal milieu in 1-mo-old Sprague-Dawley rats may be useful for probing the hormonal effects of perimenopause on age-related disease risk.

Analysis of LIN28A in early human ovary development and as a candidate gene for primary ovarian insufficiency

Lin28 proteins are emerging as important regulators of microRNAs in endocrine systems. Lin28a regulates primordial germ cell development and puberty timing in mice, whereas the related protein LIN28B is associated with age at menarche in genome-wide association studies in humans. Here, we studied expression of LIN28A and LIN28B in early human gonad development. LIN28A increased in the developing ovary between 6 and 9weeks post conception, but not in the developing testis. Immunohistochemistry demonstrated LIN28A in peripheral germ cells. LIN28B was expressed at lower levels in both tissues and did not increase with time. As disruption of Lin28a affects germ cell development in mice, LIN28A was considered a candidate gene for primary ovarian insufficiency (POI) in humans. However, no significant changes were found in 50 women studied. These findings show LIN28A is strongly expressed in germ cells during early human ovary development, but disruption of LIN28A is not a common cause of POI.

Endocrine profile of an ovariectomized cynomolgus monkey (Macaca fascicularis) with a supernumerary ovary

For 21 mo after a bilateral ovariectomy, a 19-y-old ovariectomized cynomolgus macaque (Macaca fascicularis) continued to have menstrual cycles and measurable premenopausal estradiol and progesterone concentrations. Among these 10 menstrual cycles, 5 cycles were normal in duration and 5 were prolonged. At necropsy, a firm nodule was identified in the omental fat, and histologic evaluation confirmed the presence of ovarian tissue containing various stages of atretic follicles, a regressing corpora lutea, and a degenerating antral follicle. The endometrium and vaginal epithelium were atrophic. The occurrence of ectopic ovarian tissue in any form and location is a rare gynecologic condition in both women and nonhuman primates. Previously reported cases in nonhuman primates have been incidental findings at necropsy; therefore, the steroidogenic capacity and endocrine-related sequelae of such ovarian tissue in any nonhuman primate species is unknown. Based on structure, location, and relationship to normally situated ovaries, the ovarian tissue in this case was classified as a supernumerary ovary. To our knowledge, this is the first case report of a supernumerary ovary in a cynomolgus macaque. This report demonstrates that supernumerary ovaries in nonhuman primates can be biologically active for many years beyond sexual maturity and should be considered as a possible cause for vaginal bleeding and elevated ovarian hormone concentrations after ovariectomy.

Immunology of the Testis and Male Reproductive Tract

A large body of evidence points to the existence of a close, dynamic relationship between the immune system and the male reproductive tract, which has important implications for our understanding of both systems. The testis and the male reproductive tract provide an environment that protects the otherwise highly immunogenic spermatogenic cells and sperm from immunological attack. At the same time, secretions of the testis, including androgens, influence the development and mature functions of the immune system. Activation of the immune system has negative effects on both androgen and sperm production, so that systemic or local infection and inflammation compromise male fertility. The mechanisms underlying these interactions have begun to receive the attention from reproductive biologists and immunologists that they deserve, but many crucial details remain to be uncovered. A complete picture of male reproductive tract function and its response to toxic agents is contingent upon continued exploration of these interactions and the mechanisms involved.

The response of C57BL/6J and BALB/cJ mice to increased housing density

Increased numbers of mice housed per cage (that is, increased housing density) is seen as 1 way to reduce the costs of conducting biomedical research. Current empirically derived guidelines are based on the area provided per mouse depending on body weight as documented in the Guide for the Care and Use of Laboratory Animals. The current study aimed to provide a more scientific basis for housing density by examining the response of C57BL/6J and BALB/cJ mice to increased housing density from weaning to 5 mo of age, to determine those parameters most useful for future larger-scale studies. A wide range of phenotypic characteristics--including growth rate, body composition, hematology, serum biochemistry, hormone and metabolite measurements, in-cage telemetry, behavior, and cage microenvironment--was examined at various time points. The parameters showing greatest changes were: growth rate, which was significantly reduced in animals at the highest density; adrenal gland size, the proportion of adrenal cortex, and concentration of fecal corticosterone metabolites, all of which were increased at higher densities; and anxiety and barbering, which were more pronounced at higher densities. Cage microenvironment deteriorated with increasing density, but the increases in measured parameters were small, and their biologic impact, if any, was not apparent. The current findings indicate that mouse housing density can be increased 50% to 100% above the current recommendations (as floor area per mouse) with no or few apparent affects on mouse overall wellbeing. However, weight gain, fecal corticosterone metabolite levels, and barbering differed significantly with housing density and therefore are suggested as good measures of the response to alterations in housing.

Identification, purification and characterization of a novel human blood protein with binding affinity for prostate secretory protein of 94 amino acids

PSP94 (prostate secretory protein of 94 amino acids), an abundant protein within semen, has reported local functions within the reproductive tract and reported systemic functions. Mechanisms of action remain poorly understood, but binding to undefined molecules within the prostate, pituitary, testis and blood may initiate some of these actions. PSP94 serum measurements, especially of bound and free forms, have potential clinical utility in prostate cancer management. Identification of the binding molecules will help in the understanding of PSP94's action, and enable further development of PSP94 serum assays. PSPBP (PSP94-binding protein) was purified from human serum by ammonium sulphate fractionation, ion-exchange and affinity chromatography. The glycosylated protein ran as two bands on SDS/PAGE (70 and 95 kDa). N-terminal sequencing yielded a 30-amino-acid sequence, identical with the translated N-terminal region of a previously published cDNA (GenBank accession number AX136261). Reverse transcriptase PCR and plaque hybridization demonstrated PSPBP mRNA in peripheral blood leucocytes and in a prostate cDNA library. Northern blotting showed 2 kb mRNA species in prostate, testis, ovary and intestine. Immunohistochemistry demonstrated PSPBP in tissues, including pituitary and Leydig cells, supporting a role for PSP94 in hormonal control at the pituitary gonadal axis. ELISA demonstrated that PSPBP levels were significantly lower (P=0.0014) in the serum of a prostate cancer population (n=65) compared with a control population (n=70). PSPBP identification will help the understanding of PSP94's functions and facilitate ELISA development to address the clinical value of PSP94 serum assays.