Body mass growth in common marmosets: toward a model of pediatric obesity

Whole Genome Analysis of SNV and Indel Polymorphism in Common Marmosets (Callithrix jacchus)

The common marmoset (Callithrix jacchus) is one of the most widely used nonhuman primate models of human disease. Owing to limitations in sequencing technology, early genome assemblies of this species using short-read sequencing suffered from gaps. In addition, the genetic diversity of the species has not yet been adequately explored. Using long-read genome sequencing and expert annotation, we generated a high-quality genome resource creating a 2.898 Gb marmoset genome in which most of the euchromatin portion is assembled contiguously (contig N50 = 25.23 Mbp, scaffold N50 = 98.2 Mbp). We then performed whole genome sequencing on 84 marmosets sampling the genetic diversity from several marmoset research centers. We identified a total of 19.1 million single nucleotide variants (SNVs), of which 11.9 million can be reliably mapped to orthologous locations in the human genome. We also observed 2.8 million small insertion/deletion variants. This dataset includes an average of 5.4 million SNVs per marmoset individual and a total of 74,088 missense variants in protein-coding genes. Of the 4956 variants orthologous to human ClinVar SNVs (present in the same annotated gene and with the same functional consequence in marmoset and human), 27 have a clinical significance of pathogenic and/or likely pathogenic. This important marmoset genomic resource will help guide genetic analyses of natural variation, the discovery of spontaneous functional variation relevant to human disease models, and the development of genetically engineered marmoset disease models.

Protective effects of the imidazoline-like drug lnp599 in a marmoset model of obesity-induced metabolic disorders

BACKGROUND/OBJECTIVES

Overweight and obesity are undoubtable risk factors for type 2 diabetes and cardiovascular diseases and significantly contribute to the global morbi-mortality. We previoulsy reported that LNP599, a pharmacological imidazoline-like activator of hepatic AMPK/adiponectin signaling, protects against the development of adiposity and obesity and the associated cardio-metabolic disorders, suggesting that it may be a suitable drug candidate for a therapeutic approach targeting the development of obesity at very early stages. The objective of the present study was to evaluate the metabolic effects of LNP599 in a model of diet-induced overweight and metabolic disorders in a nonhuman primate, the common marmoset (Callithrix jacchus), and more particularly to establish the impact of the compound on cholesterol homeostasis, i.e., HDL and LDL/VLDL lipoproteins.

METHODS

Marmosets were fed normal (NC) or hypercaloric (HC) chow during 16 weeks. Diet-induced changes in body weight and metabolism were assessed. Effects of LNP599 were evaluated in a subset of HC animals (HC-LNP) receiving the compound at a daily dose of 10 mg/kg over the 16 weeks.

RESULTS

HC-feeding induced significant overweight associated with a marked dyslipidemia (hypertriglyceridemia, hypercholesterolemia, and reduced HDL over LDL/VLDL cholesterol ratio). LNP599 blunted the diet-induced body weight gain and largely protected against the development of hypertriglyceridemia. Total cholesterol was unchanged but the ratio of HDL over LDL/VLDL cholesterol was more than doubled.

CONCLUSIONS

The profile of metabolic troubles obtained upon enriched diet mimicked the disorders associated with spontaneous obesity in marmosets. HC marmosets represent an experimental model of high clinical relevance to study the pathophysiology of obesity and related dyslipidemia and to evaluate the effects of emerging therapies targeting these disorders. Our data confirm the preventing effects of LNP599 in a nonhuman primate model and demonstrate for the first time the high potency of this drug in promoting HDL-cholesterol.

Marmoset Metabolism, Nutrition, and Obesity

The use of marmosets as nonhuman primate models of human disease has undergone rapid expansion in the United States in the last decade, with an emphasis in the field of neuroscience. With this expanding need, there has been an increase in the formation of small marmoset colonies. The standardization in care and husbandry techniques for marmosets has historically lagged behind other established nonhuman primate models, resulting in a great deal of variation in practices between colonies. There remains a lack of consensus and evidence-based recommendations regarding best standards for nutrition, enrichment, weight management, and diagnostics for clinical metabolic disease. Marmoset base diets vary broadly in their nutritional value, and therefore the physiological responses to these diets also vary broadly. In this review, we briefly outline what is known about nutrition for captive marmosets and highlight what is known regarding metabolic dysfunction and obesity.

Current practices in nutrition management and disease incidence of common marmosets (Callithrix jacchus)

BACKGROUND

A survey was developed to characterize disease incidence, common pathology lesions, environmental characteristics, and nutrition programs within captive research marmoset colonies.

METHODS

Seventeen research facilities completed the electronic survey.

RESULTS

Nutritional management programs varied amongst research institutions housing marmosets; eight primary base diets were reported. The most common clinical syndromes reported were gastrointestinal disease (i.e. inflammatory bowel disease like disease, chronic lymphocytic enteritis, chronic malabsorption, chronic diarrhea), metabolic bone disease or fracture, infectious diarrhea, and oral disease (tooth root abscesses, gingivitis, tooth root resorption). The five most common pathology morphologic diagnoses were colitis, nephropathy/nephritis, enteritis, chronic lymphoplasmacytic enteritis, and cholecystitis. Obesity was more common (average 20% of a reporting institution's population) than thin body condition (average 5%).

CONCLUSIONS

Through review of current practices, we aim to inspire development of evidence-based practices to standardize husbandry and nutrition practices for marmoset research colonies.

Utility of Common Marmoset (Callithrix jacchus) Embryonic Stem Cells in Liver Disease Modeling, Tissue Engineering and Drug Metabolism

The incidence of liver disease is increasing significantly worldwide and, as a result, there is a pressing need to develop new technologies and applications for end-stage liver diseases. For many of them, orthotopic liver transplantation is the only viable therapeutic option. Stem cells that are capable of differentiating into all liver cell types and could closely mimic human liver disease are extremely valuable for disease modeling, tissue regeneration and repair, and for drug metabolism studies to develop novel therapeutic treatments. Despite the extensive research efforts, positive results from rodent models have not translated meaningfully into realistic preclinical models and therapies. The common marmoset Callithrix jacchus has emerged as a viable non-human primate model to study various human diseases because of its distinct features and close physiologic, genetic and metabolic similarities to humans. C. jacchus embryonic stem cells (cjESC) and recently generated cjESC-derived hepatocyte-like cells (cjESC-HLCs) could fill the gaps in disease modeling, liver regeneration and metabolic studies. They are extremely useful for cell therapy to regenerate and repair damaged liver tissues in vivo as they could efficiently engraft into the liver parenchyma. For in vitro studies, they would be advantageous for drug design and metabolism in developing novel drugs and cell-based therapies. Specifically, they express both phase I and II metabolic enzymes that share similar substrate specificities, inhibition and induction characteristics, and drug metabolism as their human counterparts. In addition, cjESCs and cjESC-HLCs are advantageous for investigations on emerging research areas, including blastocyst complementation to generate entire livers, and bioengineering of discarded livers to regenerate whole livers for transplantation.

Maternal weight affects placental DNA methylation of genes involved in metabolic pathways in the common marmoset monkey (Callithrix jacchus)

Accumulating evidence suggests that dysregulation of placental DNA methylation (DNAm) is a mechanism linking maternal weight during pregnancy to metabolic programming outcomes. The common marmoset, Callithrix jaccus, is a platyrrhine primate species that has provided much insight into studies of the primate placenta, maternal condition, and metabolic programming, yet the relationships between maternal weight and placental DNAm are unknown. Here, we report genome‐wide DNAm from term marmoset placentas using reduced representation bisulfite sequencing. We identified 74 genes whose DNAm pattern is associated with maternal weight during gestation. These genes are predominantly involved in energy metabolism and homeostasis, including the regulation of glycolytic and lipid metabolic processes pathways.

The placental DNA methylation (DNAm) landscape of the marmoset placenta presents unique differences and similarities with human placental methylation patterns.

Maternal weight is associated with placental DNAm in genes that are predominantly involved in energy metabolism and homeostasis.

The impact of altered placental DNAm on placental function and development may also contribute to the potential role of placental DNAm in developmental programming in the marmoset monkey.

The marmoset cytochrome P450 superfamily: Sequence/phylogenetic analyses, genomic structure, and catalytic function

The common marmoset (Callithrix jacchus) is a New World monkey that has attracted much attention as a potentially useful primate model for preclinical testing. A total of 36 marmoset cytochrome P450 (P450) isoforms in the P450 1-51 subfamilies have been identified and characterized by the application of genome analysis and molecular functional characterization. In this mini-review, we provide an overview of the genomic structures, sequence identities, and substrate selectivities of marmoset P450s compared with those of human P450s. Based on the sequence identity, phylogeny, and genomic organization of marmoset P450s, orthologous relationships were established between human and marmoset P450s. Twenty-four members of the marmoset P450 1A, 2A, 2B, 2C, 2D, 2E, 3A, 4A, and 4F subfamilies shared high degrees of homology in terms of cDNA (>89%) and amino acid sequences (>85%) with the corresponding human P450s; P450 2C76 was among the exceptions. Phylogenetic analysis using amino acid sequences revealed that marmoset P450s in the P450 1-51 families were located in the same clades as their human and macaque P450 homologs. This finding underlines the evolutionary closeness of marmoset P450s to their human and macaque homologs. Most marmoset P450 1-4 enzymes catalyzed the typical drug-metabolizing reactions of the corresponding human P450 homologs, except for some differences of P450 2A6 and 2B6. Consequently, it appears that the substrate specificities of enzymes in the P450 1-4 families are generally similar in marmosets and humans. The information presented here supports a better understanding of the functional characteristics of marmoset P450s and their similarities and differences with human P450s. It is hoped that this mini-review will facilitate the successful use of marmosets as primate models in drug metabolism and pharmacokinetic studies.

The development of a specific pathogen free (SPF) barrier colony of marmosets (Callithrix jacchus) for aging research

A specific pathogen free (SPF) barrier colony of breeding marmosets (Callithrix jacchus) was established at the Barshop Institute for Longevity and Aging Studies. Rodent and other animal models maintained as SPF barrier colonies have demonstrated improved health and lengthened lifespans enhancing the quality and repeatability of aging research. The marmosets were screened for two viruses and several bacterial pathogens prior to establishing the new SPF colony. Twelve founding animals successfully established a breeding colony with increased reproductive success, improved health parameters, and increased median lifespan when compared to a conventionally housed, open colony. The improved health and longevity of marmosets from the SPF barrier colony suggests that such management can be used to produce a unique resource for future studies of aging processes in a nonhuman primate model.

MR Imaging Properties of ex vivo Common Marmoset Brain after Formaldehyde Fixation

Purpose:

Ex vivo brains have different MRI properties than in vivo brains because of chemical changes caused by fixative solutions, which change the signal intensity and/or tissue contrast on MR images. In this study, we investigated and compared the MRI properties of in vivo and ex vivo brains.

Methods:

Using a Bruker 9.4T experimental scanner unit for animals (Biospin GmbH, Ettlingen, Germany), we performed this study on the common marmoset. We measured the relaxation and diffusion values in the white matter and cortex of common marmosets and compared these values between in vivo brains (n = 20) and ex vivo brains (n = 20). Additionally, we observed the relationship between the tissue fixation duration and MRI properties by imaging a brain that underwent long-term fixation in a preliminary examination (n = 1).

Results:

The T₁ values of ex vivo brains were decreased compared with those of in vivo brains; however, there were no significant difference in the T₂ and T2* values of in vivo and ex vivo brains. Axial, radial, and mean diffusivity values of ex vivo brains decreased to approximately 65% and 52% of those of in vivo brains in the cortex and white matter, respectively. Conversely, fractional anisotropy values were not significantly different between in vivo and ex vivo brains.

Conclusion:

The T₁ values and diffusion coefficient values of the ex vivo brains were strikingly different than those of the in vivo brains. Conversely, there were no significant changes in the T₂, T2* or fractional anisotropy values. Altogether, the dehydration caused by tissue fixation and the reduction in brain temperature were involved in changing the relaxation and diffusion coefficient values. Here, it was difficult to specify all factors causing these changes. Further detailed study is needed to examine changes in MRI properties.

Long-term treatment with the mTOR inhibitor rapamycin has minor effect on clinical laboratory markers in middle-aged marmosets

Interventions to extend lifespan and improve health with increasing age would have significant impact on a growing aged population. There are now several pharmaceutical interventions that extend lifespan in laboratory rodent models with rapamycin, an inhibitor of mechanistic target of rapamycin (mTOR) being the most well studied. In this study, we report on the hematological effects in a cohort of middle-aged common marmosets (Callithrix jacchus) that were enrolled in a study to test the effects of daily rapamycin treatment on aging in this species. In addition, we assessed whether sex was a significant factor in either baseline assessment or as an interaction with rapamycin treatment. Among our cohort at baseline, we found few differences in either basic morphology or hematological markers of blood cell counts, metabolism or inflammation between male and female marmosets. After dosing with rapamycin, surprisingly we found trough blood concentrations of rapamycin were significantly lower in female compared to male marmosets. Despite this pharmacological difference, both sexes had only minor changes in cellular blood counts after 9 months of rapamycin. These data then suggest that the potential clinical hematological side effects of rapamycin are not likely outcomes of long-term rapamycin in relatively healthy, middle-aged marmosets.

The common marmoset monkey: avenues for exploring the prenatal, placental, and postnatal mechanisms in developmental programming of pediatric obesity

Animal models have been critical in building evidence that the prenatal experience and intrauterine environment are capable of exerting profound and permanent effects on metabolic health through developmental programming of obesity. However, despite physiological and evolutionary similarities, nonhuman primate models are relatively rare. The common marmoset monkey ( Callithrix jacchus) is a New World monkey that has been used as a biomedical model for well more than 50 years and has recently been framed as an appropriate model for exploring early-life impacts on later health and disease. The spontaneous, multifactorial, and early-life development of obesity in the common marmoset make it a valuable research model for advancing our knowledge about the role of the prenatal and placental mechanisms involved in developmental programming of obesity. This paper provides a brief overview of obesity in the common marmoset, followed by a discussion of marmoset reproduction and placental characteristics. We then discuss the occurrence and utility of variable intrauterine environments in developmental programming in marmosets. Evidence of developmental programming of obesity will be given, and finally, we put forward future directions and innovations for including the placenta in developmental programming of obesity in the common marmoset.

Obesity and obesogenic growth are both highly heritable and modified by diet in a nonhuman primate model, the African green monkey (Chlorocebus aethiops sabaeus)

Objective:

In humans, the ontogeny of obesity throughout the life course and the genetics underlying it has been historically difficult to study. We compared, in a non-human primate model, the lifelong growth trajectories of obese and non-obese adults to assess the heritability of and map potential genomic regions implicated in growth and obesity.

Study population:

A total of 905 African green monkeys, or vervets (Chlorocebus aethiops sabaeus) (472 females, 433 males) from a pedigreed captive colony.

Methods:

We measured fasted body weight (BW), crown-to-rump length (CRL), body-mass index (BMI) and waist circumference (WC) from 2000 to 2015. We used a longitudinal clustering algorithm to detect obesogenic growth, and logistic growth curves implemented in nonlinear mixed effects models to estimate three growth parameters. We used maximum likelihood variance decomposition methods to estimate the genetic contributions to obesity-related traits and growth parameters, including a test for the effects of a calorie-restricted dietary intervention. We used multipoint linkage analysis to map implicated genomic regions.

Results:

All measurements were significantly influenced by sex, and with the exception of WC, also influenced by maternal and post-natal diet. Chronic obesity outcomes were significantly associated with a pattern of extended growth duration with slow growth rates for BW. After accounting for environmental influences, all measurements were found to have a significant genetic component to variability. Linkage analysis revealed several regions suggested to be linked to obesity-related traits that are also implicated in human obesity and metabolic disorders.

Conclusions:

As in humans, growth patterns in vervets have a significant impact on adult obesity and are largely under genetic control with some evidence for maternal and dietary programming. These results largely mirror findings from human research, but reflect shorter developmental periods, suggesting that the vervet offers a strong genetic model for elucidating the ontogeny of human obesity.

The common marmoset: An overview of its natural history, ecology and behavior

Callithrix jacchus are small-bodied Neotropical primates popularly known as common marmosets. They are endemic to Northeast Brazil and occur in contrasting environments such as the humid Atlantic Forest and the dry scrub forest of the Caatinga. Common marmosets live in social groups, usually containing only one breeding pair. These primates have a parental care system in which individuals help by providing assistance to the infants even when they are not related to them. Free-ranging groups use relatively small home ranges (0.5-5 hectares) and have an omnivorous diet. Because of the shape of their teeth, they actively gouge tree bark to extract and consume exudates. When foraging for live prey, they adjust their strategy according to the type of prey. The successful use of appropriate hunting strategies depends not only on age but also on prey type and seems to be mediated by learning and experience. Indeed, common marmosets have shown unexpected cognitive abilities, such as true imitation. All these aspects seem to have contributed to the ecological success of this species. Callithrix jacchus has been widely studied, especially in captivity; even so, a number of questions remain to be answered about its biology, ecology, and behavior, both in captivity and the wild. A richer understanding of marmosets' natural behavior and ecology can have a significant impact on shaping ongoing and future neuroscience research. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 244-262, 2017.

Cognitive impairment in a young marmoset reveals lateral ventriculomegaly and a mild hippocampal atrophy: a case report

The number of studies that use the common marmoset (Callithrix jacchus) in various fields of neurosciences is increasing dramatically. In general, animals enter the study when their health status is considered satisfactory on the basis of classical clinical investigations. In behavioral studies, variations of score between individuals are frequently observed, some of them being considered as poor performers or outliers. Experimenters rarely consider the fact that it could be related to some brain anomaly. This raises the important issue of the reliability of such classical behavioral approaches without using complementary imaging, especially in animals lacking striking external clinical signs. Here we report the case of a young marmoset which presented a set of cognitive impairments in two different tasks compared to other age-matched animals. Brain imaging revealed a patent right lateral ventricular enlargement with a mild hippocampal atrophy. This abnormality could explain the cognitive impairments of this animal. Such a case points to the importance of complementing behavioral studies by imaging explorations to avoid experimental bias.

Developmental origins of pregnancy loss in the adult female common marmoset monkey (Callithrix jacchus)

BACKGROUND

The impact of the intrauterine environment on the developmental programming of adult female reproductive success is still poorly understood and potentially underestimated. Litter size variation in a nonhuman primate, the common marmoset monkey (Callithrix jacchus), allows us to model the effects of varying intrauterine environments (e.g. nutrient restriction, exposure to male womb-mates) on the risk of losing fetuses in adulthood. Our previous work has characterized the fetuses of triplet pregnancies as experiencing intrauterine nutritional restriction.

METHODOLOGY/PRINCIPAL FINDINGS

We used over a decade of demographic data from the Southwest National Primate Research Center common marmoset colony. We evaluated differences between twin and triplet females in the number of pregnancies they produce and the proportion of those pregnancies that ended in fetal loss. We found that triplet females produced the same number of total offspring as twin females, but lost offspring during pregnancy at a significantly higher rate than did twins (38% vs. 13%, p = 0.02). Regardless of their own birth weight or the sex ratio of the litter the experienced as fetuses, triplet females lost more fetuses than did twins. Females with a male littermate experienced a significant increase in the proportion of stillbirths.

CONCLUSIONS/SIGNIFICANCE

These striking findings anchor pregnancy loss in the mother's own fetal environment and development, underscoring a "Womb to Womb" view of the lifecourse and the intergenerational consequences of development. This has important translational implications for understanding the large proportion of human stillbirths that are unexplained. Our findings provide strong evidence that a full understanding of mammalian life history and reproductive biology requires a developmental foundation.

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.

Metabolic consequences of the early onset of obesity in common marmoset monkeys

OBJECTIVE

The common marmoset as a model of early obesity was assessed. The hypotheses that juvenile marmosets with excess adipose tissue will display higher fasting glucose, decreased insulin sensitivity, and decreased ability to clear glucose from the blood stream were tested.

DESIGN AND METHODS

Normal and obese (body fat > 14%) common marmoset infants (N = 39) were followed up from birth until 1 year. Body fat was measured by quantitative magnetic resonance. Circulating glucose was measured by glucometer and insulin, adiponectin, and leptin by commercial assays. The quantitative insulin sensitivity check index (QUICKI; a measure of insulin sensitivity) was calculated for subjects with fasting glucose and insulin measures. Oral glucose tolerance tests (OGTTs) were conducted at 12 months on 35 subjects.

RESULTS

At 6 months, obese subjects already had significantly lower insulin sensitivity (mean QUICKI = 0.378 ± 0.029 vs. 0.525 ± 0.019, N = 11, P = 0.003). By 12 months, obese subjects also had higher fasting glucose (129.3 ± 9.1 mg/dL vs. 106.1 ± 6.5 mg/dL, P = 0.042), and circulating adiponectin tended to be lower (P = 0.057). Leptin was associated with percent body fat; however, birth weight also influenced circulating leptin. The OGTT results demonstrated that obese animals had a decreased ability to clear glucose.

CONCLUSIONS

Early-onset obesity in marmosets results in impaired glucose homeostasis by 1 year.

Relation of food intake behaviors and obesity development in young common marmoset monkeys

OBJECTIVE

Increasing prevalence of childhood obesity and associated risks of adult type disease have led to worldwide concern. It remains unclear how genetic predisposition, environmental exposure to obesogenic food, and developmental programming interact to lead to overweight and obese children. The development of a nonhuman primate model of obesity, and particularly juvenile obesity, is an important step to elucidating the factors associated with obesity and evaluating intervention strategies.

DESIGN AND METHODS

Infant marmosets were followed from birth to 12 months of age. Feeding phenotypes were determined through the use of behavioral observation, solid food intake trials, and liquid feeding trials monitored via lickometer.

RESULTS

Marmosets found to be obese at 12 months of age (more than 14% body fat) start consuming solid food sooner and initiate more time off of care givers. These individuals developed stable feeding phenotypes that included being more efficient consumers during liquid intake trials, drinking more grams of diet per contact with the licksit.

CONCLUSIONS

The weaning process appears to be particularly important in the development of feeding phenotypes and the development of juvenile obesity for the marmosets, and thus this is the time that should be focused upon for intervention testing in both nonhuman primates and children.

Valores eletrocardiográficos em saguis-de-tufo-preto (Callithrix penicillata)

O conhecimento de parâmetros cardíacos em animais modelo experimentais é essencial para a investigação médica comparativa. Nosso estudo teve como objetivo estabelecer parâmetros eletrocardiográficos e valores de referência para saguis-de-tufo-preto (Callithrix penicillata). Dezenove saguis-de-tufo-preto adultos saudáveis foram utilizados. Uma combinação de tiletamina e zolazepam foi empregada para contenção química antes da realização do exame eletrocardiográfico (ECG). Foi utilizado para o exame de ECG um equipamento computadorizado. Os valores dos parâmetros do ECG encontrados foram frequência cardíaca média de 264±74 bpm, uma variação do eixo cardíaco médio entre 60° e -90°, a duração da onda P média de 34±6ms e amplitude de 0,132±0,051mV, um intervalo PR com duração de 56±11ms, duração média do complexo QRS de 35±7ms e amplitude de 0,273±0,269mV, duração do intervalo QT de 130±26ms, segmento ST isoelétrico (13 animais) e com supradesnível (seis animais) e uma amplitude de onda T de 0,19±0,083mV e com polaridade positiva. Não houve diferença significativa entre machos e fêmeas. Os parâmetros eletrocardiográficos obtidos em nosso estudo em saguis-de-tufo-preto podem ser utilizados como referência em outras pesquisas futuras, oferecendo aos pesquisadores parâmetros eletrocardiográficos que contribuem com a literatura.

Toward a nonhuman primate model of fetal programming: phenotypic plasticity of the common marmoset fetoplacental complex

Nonhuman primates offer unique opportunities as animal models in the study of developmental programming and the role of the placenta in developmental processes. All primates share fundamental similarities in life history and reproductive biology. Thus, insights gleaned from studies of nonhuman primates have a higher degree of biological salience to human biology than do studies of rodents or agricultural animals. The common marmoset monkey is a small-bodied primate from South America that produces litters of dizygotic fetuses that share a single placental mass. This natural variation allows us to model different intrauterine conditions and associated fetoplacental phenotypes. The marmoset placenta is phenotypically plastic according to litter size. Triplet litters are characterized by low individual fetal weights and significantly more efficient placentas and attendant alterations to the microscopic architecture and endocrine function, thus modeling a nutrient restricted intrauterine environment. Consistent with this model, triplet neonates experience a higher risk of perinatal mortality and an increased likelihood of elevated adult weight. Recent evidence has shown that the intrauterine experience of females has an impact on their own pregnancy outcomes in adulthood: triplet females experience significantly greater pregnancy loss than do twin females. The marmoset monkey thus represents a potential powerful nonhuman primate model of multiple pregnancies, restrictive prenatal experiences, and differential reproductive outcomes in adulthood, which may have important implications for studying the impact of in vitro fertilization on adult reproductive health. It is still too early to determine exactly what developmental pathways lead to this disparity or what specific role the placenta plays; future work on this front will be critical to establish the marmoset as an important model of fetal programming of reproductive function in adulthood and across generations.