Effect of menstrual cycle phase and hormonal treatments on evaluation of tubal patency in baboons.

BACKGROUND: We evaluated whether menstrual cycle phase influences the assessment of tubal patency by hysterosalpingography (HSG) in baboons. METHODS: Retrospective analysis of baseline tubal patency studies and serum estradiol (E2 ) and progesterone (P4) values obtained from female baboons used as models for development of non-surgical permanent contraception in women. The main outcome measure was bilateral tubal patency (BTP) in relationship with estradiol level. RESULTS: Female baboons (n = 110) underwent a single (n = 81), two (n = 26), or three (n = 3) HSG examinations. In 33/142 (23%) HSG examinations, one or both tubes showed functional occlusion (FO). The median E2 in studies with BTP (49 pg/mL) was significantly higher than in those studies with FO (32 pg/mL, P = .005). Among 18 animals with repeat examinations where serum E2 changed from <60 to ≥ 60 pg/mL, 13 results changed from FO to BTP (P = .0001). No sets showed a change from BTP to FO with an increase in estradiol. CONCLUSION: In baboons, functional occlusion of the fallopian tube is associated with low estradiol levels, supporting a role for estrogen-mediated relaxation of the utero-tubal junction.

Insulin resistance elicited in postpubertal primate offspring deprived of estrogen in utero.

We recently demonstrated that offspring delivered to baboons deprived of estrogen during the second half of gestation exhibited insulin resistance prior to onset of puberty. Because gonadal hormones have a profound effect on insulin action and secretion in adults, we determined whether insulin resistance is retained after initiation of gonadal secretion of testosterone and estradiol. Glucose tolerance tests were performed in postpubertal baboon offspring of untreated and letrozole-treated animals (serum estradiol reduced >95 %). Basal fasting levels of insulin (P < 0.05) and peak 1 min and 1 + 3 + 5 min levels of glucose after glucose tolerance tests challenge (P < 0.03) were greater in offspring delivered to letrozole-treated, estrogen-deprived baboons than untreated animals. Moreover, the value for the HOMA-IR, an accepted index of insulin resistance, was 2-fold greater (P < 0.05) in offspring delivered to baboons treated with letrozole than in untreated animals. Collectively these results support the proposal that estrogen normally has an important role in programming mechanisms in utero within the developing fetus that lead to insulin sensitivity after birth.

Influence of diet and stress on reproductive hormones in Nigerian olive baboons.

A female mammal's reproductive function and output are limited by the energy she is able to extract from her environment. Previous studies of the interrelationships between energetic circumstances and reproductive function in a variety of mammal species have produced varied results, which do not all support the common assumption that higher female reproductive hormone levels, specifically progesterone, indicate better ovarian function and greater reproductive potential, and are associated with lower energetic stress. In the present study faecal progesterone and glucocorticoid levels were assessed in two troops of olive baboons (Papio anubis) in the same population. They face similar ecological challenges, except that one troop crop-raids, potentially affecting its energetic intake and stress levels. The energy intake of individual females was assessed by combining detailed feeding observations with nutritional analysis of food samples. The crop-raiding troop experienced 50% higher energy intake rates and 50% lower glucocorticoid levels compared to the non-crop-raiding troop alongside substantially lower progesterone levels. This suggests that energetic stress is associated with elevated progesterone levels and may be the cause of the non-crop-raiding troop's lower reproductive output. By comparing groups which differ little, except in terms of food access, and also by directly assessing energy intake, our study addresses some of the design limitations of previous research investigating variation in progesterone levels and energetic stress. It therefore has the potential to contribute to greater understanding of the factors affecting differences in reproductive and stress hormone levels and reproductive function in mammals experiencing different energetic circumstances.

Changes in eutopic endometrial gene expression during the progression of experimental endometriosis in the baboon, Papio anubis.

Endometriosis is associated with aberrant gene expression in the eutopic endometrium of women with disease. To determine if the development of endometriotic lesions directly impacts eutopic endometrial gene expression, we sequentially analyzed the eutopic endometrium across the time course of disease progression in a baboon model of induced disease. Endometriosis was induced in baboons (n = 4) by intraperitoneal inoculation of autologous menstrual endometrium. Eutopic endometria were collected during the midsecretory phase (Days 9-11 postovulation) at 1, 3, 6-7, 10-12, and 15-16 mo after disease induction and compared with tissue from disease-free baboons. RNA was hybridized to Human Genome U133 Plus 2.0 Arrays, and data were extracted using Gene-Chip Operating Software. Subsequently, both Gene Set Enrichment Analysis and Ingenuity Pathways Analysis were used to find biological states that have a statistically significant enrichment concomitant with pairwise comparison of human endometriosis arrays. Within 1 mo of induction of the disease, 4331 genes were differentially expressed (P < 0.05). Hierarchical clustering revealed self-segregation into two groups-a) 1, 3, and 10-12 mo and b) 6-7 and 15-16 mo-together with controls. Clustering analysis at each stage of disease validated dysregulation of several signaling pathways, including Nodal-like receptor, EGF, ERK/MAPK, and PI3/AKT. Sequential analysis of the same animals during disease progression demonstrated an early disease insult and a transitory dominance of an estrogenic phenotype; however, as the disease progressed, a progesterone-resistant phenotype became evident. Furthermore, we demonstrate a 38.6% differential gene expression overlap with endometrial samples in the midsecretory phase from women with endometriosis, concomitant with similar dysregulation in human disease candidate genes Fos, Nodal, Suclg2, and Kras, among others. Molecular changes in the eutopic endometrium, associated with endometriosis, are directly impacted by endometriotic lesions, providing strong evidence that it is the disease rather than inherent defective endometrium that results in aberrant gene expression in the eutopic endometrium. Furthermore, this baboon model provides a powerful means whereby the early events associated with the pathology of disease and the resulting infertility may be elucidated.

Darwin's monkey: why baboons can't become human.

Baboons were used in the past as models for human evolution. I utilize 40 years of data from my long-term study on baboons in Kenya to suggest that baboons are once again relevant for understanding human evolution, not as a referential model but to reset the starting conditions of the human experiment. The baboon data also offer a critique of widely held ideas about how natural selection might work by looking at real lives in real time. This situates competition in a matrix of collaboration and illustrates the critical role of chance, contingency, and history in baboon survival and success. I make three methodological moves to reach these conclusions. The first is to focus on process not just outcome. The second is to look at time scales longer than usual studies but shorter than evolutionary time as a way to open the black box that currently links behavior to evolutionary value. The third is to use comparative natural history, Darwin's method, as a way to capture and comprehend how complexity is generated and how baboons deal with it in their daily lives. These empirical and methodological turns lead to conclusions that run counter to widely held ideas about baboons, about primates, and about the determinism of natural selection. I follow my own research history to illustrate these points. The discussion ranges from alternative interpretations of the male and the female dominance hierarchies, to insights from a fission that happened when the foraging strategy of raiding and nonraiding baboons diverged, to evidence of adaptation after translocation, and finally to assessing two unusual fusions of baboon groups. Altogether, these natural histories yield baboon "principles of the social" with insights about cognition, cooperation, and culture and suggest why baboons can't become human. The data also support Weiss and Buchanan's framework (The Mermaid's Tale: Four Billion Years of Cooperation in the Making of Living Things. Cambridge, MA: Harvard University Press,2009. 305 p) with its alternative view of natural selection in which there is more slippage and tolerance, multiple solutions with larger acceptability spaces, and the possibility that an adaptive fit will be "good enough" rather than seamless. However, capturing behavioral complexity "in the wild" poses methodological challenges. Long-term field studies provide critical information but the current quantitative methods should be expanded also include natural history observations of behaviors and events across time, space, groups, and landscapes. Finally, the baboon natural histories illustrate how the evolutionary game has changed in the Anthropocene yielding a cautionary tale about the future for many primate species.

Randomized comparison of different ovarian stimulation regimens for assisted reproductive technology in baboons (Papio anubis).

OBJECTIVE: To compare different methods of ovarian stimulation (OS) for assisted reproductive technology in baboons. DESIGN: Prospective randomized study. SETTING: Institute of primate research. ANIMAL(S): Baboons (n = 10) were randomized into two groups (of five animals each) during three different cycles to compare six protocols of OS. INTERVENTION(S): Cycle 1: clomiphene citrate (CC) alone (group CC) versus CC and GnRH agonist (group CC-Ag); cycle 2: recombinant gonadotropins (GON) without GnRH agonist (group GON) versus GON and depot GnRH agonist (group GON-AgDepo-1); cycle 3: GON and depot GnRH agonist (group GON-AgDepo-2) versus GON and daily GnRH agonist in a classic long protocol (group GON-Ag). Oocyte aspiration was performed 34-36 hours after injecting 5,000 IU rhCG, followed by fertilization via intracytoplasmic sperm injection (ICSI). MAIN OUTCOME MEASURE(S): Number and quality of oocytes retrieved and their fertilization rate. RESULT(S): More metaphase II (MII) oocytes were retrieved using the GON-AgDepo-1 (n = 12; 64% MII), GON-AgDepo-2 (n = 9; 79% MII), GON-Ag (n = 16; 88% MII), and GON (n = 6; 59% MII) protocols compared with the CC (n = 9; 15% MII) and CC-Ag (n = 14; 20% MII) protocols. Fertilization by ICSI varied between 43% and 71%. CONCLUSION(S): In baboons, long and depot protocols yield similar numbers of MII oocytes; however, depot protocol may be preferable because only one injection of GnRH agonist is needed.

Female reproductive signaling, and male mating behavior, in the olive baboon.

Baboon sexual swellings are among the largest and most colorful signals displayed by any mammal, and many baboon studies have shown an association between sexual swellings and both female and male sexual behavior. However, the extent to which female behavior and sexual swellings combine to signal the timing of ovulation and the fertile period to males, and the extent to which males use these and other signals when determining patterns of mating behavior, remain key topics of research. Here we assess the social and sexual behavior of both female and male olive baboons with respect to detailed measures of swelling size made from digital photographs, measures of fecal progestogen and estrogen levels, and estimates of the timing of ovulation and the fertile period based on those levels. Female aggression and grooming behavior were unrelated to fecal progestogen and estrogen levels, but there were some significant relationships between these hormonal measures and presenting behaviors. Measures of female behavior collected during the study did not appear to reveal the timing of ovulation or the fertile period. Male consortship behavior was closely tied to fine-scale changes in sexual swelling size, but copulation behavior was not. Copulation behavior of consorting males was, however, linked to the timing of both ovulation and the fertile period, suggesting that males did have knowledge about these timings. Together these results suggest that males used fine-scale swelling size changes when deciding when to consort, but that consorting males did not use fine-scale swelling size changes in deciding when to copulate. We propose that swelling size may advertise the period during which males should consort with females, with other signals available only from closer inspection then used by consorting males to assess the timing of the fertile period more accurately. An important implication of this interpretation is that different males may have access to different signals of ovulation at any one time. Such a system would allow females to offer different males different information simultaneously, perhaps offering a solution to the 'female dilemma' of how females can simultaneously assure and confuse paternity in multi-male societies.

Oocytes of baboon fetal primordial ovarian follicles express estrogen receptor beta mRNA.

In fetal ovaries of estrogen-suppressed baboons, we have previously shown that follicle numbers were 50% lower than in estrogen-replete animals and contained oocytes with a reduced number of microvilli. In the baboon fetal ovary, although estrogen receptor (ER)alpha and beta have been detected by immunocytochemistry in granulosa cells, it is not known whether oocytes express ER. Because the actions of estrogen are mediated by interaction with cell-specific receptors, the current study determined whether ERalpha/beta mRNA were expressed in oocytes of baboon fetal ovaries obtained on day 165 (term = day 184) of gestation. Oocyte nuclei and cytoplasm from primordial follicles were isolated by laser capture microdissection and ERalpha, ERbeta, GATA-4 (granulosa cell specific marker) mRNAs, and 18S rRNA determined by RT-PCR and products verified by sequencing. ERbeta mRNA was expressed in oocytes of 5 of 5 fetuses. In contrast, fetal oocytes did not express ERalpha mRNA. Although 18S rRNA was expressed in all oocytes, GATA-4 mRNA was not detected in oocytes and only detected in granulosa cells confirming purity of oocytes sampled. We conclude that oocytes of the fetal baboon ovary express ERbeta mRNA, thereby providing a mechanism by which estrogen regulates oocyte function, e.g. microvillus development.

Olive baboon (Papio anubis anubis) as a model for intrauterine research.

BACKGROUND: The Olive baboon is a popular animal model for reproductive and surgical research. The Institute of Primate Research, Nairobi, Kenya, has been using the animal for reproductive research for many years. In the baboon, compared with other smaller non-human primates, it is possible to insert uterine probes such as, catheters, curettes and other linear instruments (to cannulate cervix for uterine procedures like flushing, endometrium biopsy, embryo transfer, etc.). METHODS: However we noticed in a few animals this was difficult and problematic, particularly in some stages of the menstrual cycle, in retroverted uteri, in extensive adhesions or in some anatomically unique animals and we have developed a technique called 'Chai technique' for this purpose. RESULTS AND CONCLUSIONS: The Chai technique is unique to the baboon and not possible in human. It does not seem to cause injuries as frequently as uterine perforation and, in our experience, has been surprisingly successful.

The timed-pregnant baboon animal model can be used for determining the role of soluble vascular endothelial growth factor receptors 1 and 2 during development.

BACKGROUND: During pregnancy, mechanisms that allow for regulation of continuous fetal and placental vasculogenesis with prevention of maternal neo-vascularization remain elusive. The vascular endothelial growth factor (VEGF) biological system has a key role during vasculogenesis. The aims of this study were to validate a bioassay for soluble vascular endothelial growth factor receptors 1 and 2 (sVEGFR-1 and sVEGFR-2) in baboon plasma and to determine the maternal and fetal plasma concentration of these receptors at the end of the baboon pregnancy. METHODS: Maternal peripheral blood samples were obtained from eight baboons (Papio anubis) prior to elective cesarean section and from the umbilical cord after the fetuses were delivered. Spike and recovery experiments at various concentrations in pooled baboon maternal plasma were used to validate a human quantitative sandwich immunoassay for sVEGFR-1 and -2. Concentrations of sVEGFR-1 and -2 were then determined in maternal and fetal plasma samples. RESULTS: No significant correlations were observed between sVEGFR-1 or -2 concentrations in maternal and fetal circulations. The concentration of sVEGFR-1 was at least 30 times greater and that of sVEGFR-2 approximately two times greater, in maternal than in cord plasma (both P < 0.01). CONCLUSION: These findings suggest that baboons can be used to study the regulation of vasculogenesis during pregnancy.

Assessment of buprenorphine, carprofen, and their combination for postoperative analgesia in olive baboons (Papio anubis).

This study compared the efficacy of buprenorphine, carprofen, and a combination of the 2 analgesics in female baboons. Physiologic and behavioral parameters were assessed at baseline and postoperatively for 6 d by use of continuous noninvasive physiologic monitoring and twice-daily videotaping. Prior to surgery, all animals received a pre-emptive dose of either 0.01 mg/kg buprenorphine intramuscularly, 2.2 mg/kg carprofen intramuscularly, or a combination of 0.01 mg/kg buprenorphine and 2.2 mg/kg carprofen intramuscularly. All animals in the carprofen (n = 4) and buprenorphine+carprofen (n = 4) treatment groups appeared to have sufficient analgesia. Three of 4 animals in the buprenorphine group had adequate analgesia. The fourth animal had an elevated heart rate and spent less time standing during the postoperative period. In this study, the use of carprofen or a combination of carprofen plus buprenorphine provided more reliable postoperative analgesia than buprenorphine alone.

Induced endometriosis in the baboon (Papio anubis) increases the expression of the proangiogenic factor CYR61 (CCN1) in eutopic and ectopic endometria.

The expression of human CYR61 (cysteine-rich, angiogenic inducer, 61; CCN1) mRNA has been previously shown to be deregulated in the endometrium of women with endometriosis. We have chosen the baboon model (Papio anubis) of induced endometriosis to clarify whether CYR61 mRNA upregulation is predisposed to an inappropriately differentiated endometrium or is deregulated as a response to the presence of ectopic lesions. In the baboon, endometrial CYR61 mRNA expression underwent moderate cyclical variation, with a significant 7.3-fold increase detected at Day 2 postmenses when compared to endometrium from the proliferative and secretory phases. The CYR61 transcript was extensively upregulated in the eutopic endometrium from all baboons with induced endometriosis, as early as 1 mo postinoculation of menstrual tissue into the peritoneal cavity. CYR61 mRNA expression then decreased throughout progression of the disease, but remained higher compared to control tissues. Ectopic endometriotic lesions showed a further increase in CYR61 mRNA, with highest expression found in red lesions. Moreover, the expression levels of CYR61 transcripts correlated significantly with those of VEGF. Immunohistochemistry revealed the presence of CYR61 protein in glandular and luminal epithelial cells as well as in blood vessels of eutopic and ectopic endometrium. As in humans, increased levels of CYR61 mRNA correlated with the development of endometriosis in baboons. The increase of CYR61 mRNA in eutopic endometrium of baboons following peritoneal inoculation with menstrual endometrium provides evidence for a feedback mechanism from resulting lesions to induce a shift in gene expression patterns in the eutopic endometrium.