Evidence for independent evolution of functional progesterone withdrawal in primates and guinea pigs

Nnamani, Mauris C.; Plaza, Silvia Leonor Olivera; Romero, Roberto; Wagner, Günter P.

doi:10.1093/emph/eot022

Cited by 18 publications

(20 citation statements)

References 63 publications

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“…These findings in 2 rodent species and a variety of strains, as well as in women (15), indicate that structural changes in the stroma, i.e., reduced cell nuclei density and degradation of cross-linked collagen while progesterone in circulation is elevated, occur well before the uterus develops contractile capabilities for labor at term (62). The apparent withdrawal of progesterone efficacy in rodents and humans for cervix ripening, does not contradict clear evidence that the decline in serum progesterone is likely to be important for labor in rodents and other species compared to sustained high concentrations in circulation in primates throughout pregnancy (81,82). Perhaps the more important insight from these studies in rodents and from early reviews of cervix remodeling in women is that the ripening phase occurs well before term and is distinct from the dilation phase, which is associated with dilatability in response to labor.…”

Section: Ripeningmentioning

confidence: 99%

Immunobiology of Cervix Ripening

Yellon

2020

Front. Immunol.

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The cervix is the essential gatekeeper for birth. Incomplete cervix remodeling contributes to problems with delivery at or post-term while preterm birth is a major factor in perinatal morbidity and mortality in newborns. Lack of cervix biopsies from women during the period preceding term or preterm birth have led to use of rodent models to advanced understanding of the mechanism for prepartum cervix remodeling. The critical transition from a soft cervix to a compliant prepartum lower uterine segment has only recently been recognized to occur in various mammalian species when progesterone in circulation is at or near the peak of pregnancy in preparation for birth. In rodents, characterization of ripening resembles an inflammatory process with a temporal coincidence of decreased density of cell nuclei, decline in cross-linked extracellular collagen, and increased presence of macrophages in the cervix. Although a role for inflammation in parturition and cervix remodeling is not a new concept, a comprehensive examination of literature in this review reveals that many conclusions are drawn from comparisons before and after ripening has occurred, not during the process. The present review focuses on essential phenotypes and functions of resident myeloid and possibly other immune cells to bridge the gap with evidence that specific biomarkers may assess the progress of ripening both at term and with preterm birth. Moreover, use of endpoints to determine the effectiveness of various therapeutic approaches to forestall remodeling and reduce risks for preterm birth, or facilitate ripening to promote parturition will improve the postpartum well-being of mothers and newborns. The maternal immune system in mammals adapts to tolerate the differentiation of novel structures associated with the fetal allograft. Development of two interfaces protect the fetus from rejection and assault by the ecology of the external environment. The internal fetal-maternal interface, as represented by the fetal membranes, placenta, and decidua, is crucial for maintaining maternal inflammatory reactivity for surveillance and responses to pathogens. Discussion of the internal interface is elsewhere and in this special volume (1-3). However, the present review is focused on the external fetal-maternal interface consisting of an amniotic fluid buffer, in a forebag region later in pregnancy as the fetal head engages the lower uterus, and the fetal membranes as they press against the internal os of the cervix. This description of a singleton pregnancy in primates near term applies to rodents, despite anatomical differences in the uterus described below, because observations indicate a single fetal sac engages the internal os of the cervix shortly before labor. The success of this external interface to fend off the biome and virome in the vagina reflects the barrier function of the cervix to protect both the fetus and maternal host structures in the uterus. The cervix barrier function has both immunological and structural components. One part of the mate...

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Section: Ripeningmentioning

confidence: 99%

Immunobiology of Cervix Ripening

Yellon

2020

Front. Immunol.

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“…The detailed mechanisms of birth in guinea pig are not well understood. However, recent work on cervix found expression of P4-metabolizing enzymes in term cervix, suggesting that the shift toward proinflammatory activity of birth is triggered by potentially independently evolved local P4 withdrawal (Nnamani et al 2013). Notably, local withdrawal also appears to be the main mechanism in sheep, which, like primates, experience the luteal -placental shift, but also show overt P4 withdrawal at term.…”

Section: What Can Animals Reveal About Human Pregnancy and Parturitiomentioning

confidence: 99%

“…Extending the limited knowledge in various species of these mechanisms, occurring regardless of the decrease of systemic P4, is a promising future avenue. As suggested by Nnamani et al (2013) for the guinea pig, preliminary insights can be attained via transcriptomic analyses.…”

Section: What Can Animals Reveal About Human Pregnancy and Parturitiomentioning

confidence: 99%

Genomics of Preterm Birth

Swaggart

Pavličev

Muglia

2015

Cold Spring Harbor Perspectives in Medicine

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The molecular mechanisms controlling human birth timing at term, or resulting in preterm birth, have been the focus of considerable investigation, but limited insights have been gained over the past 50 years. In part, these processes have remained elusive because of divergence in reproductive strategies and physiology shown by model organisms, making extrapolation to humans uncertain. Here, we summarize the evolution of progesterone signaling and variation in pregnancy maintenance and termination. We use this comparative physiology to support the hypothesis that selective pressure on genomic loci involved in the timing of parturition have shaped human birth timing, and that these loci can be identified with comparative genomic strategies. Previous limitations imposed by divergence of mechanisms provide an important new opportunity to elucidate fundamental pathways of parturition control through increasing availability of sequenced genomes and associated reproductive physiology characteristics across diverse organisms.

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“…In primates, the source of progesterone shifts from the ovaries to the placenta in early pregnancy, and high progesterone levels are maintained throughout gestation (Haluska et al, 1997). Importantly, progesterone production by the placenta does not decline prior to birth in Catarrhine primates (Nnamani et al, 2013). Instead the fall in progesterone action is said to be functional involving local mechanisms such as target tissue metabolism and changing progesterone receptor expression and function (Zakar and Mesiano, 2011).…”

Section: Guinea Pig Model Of Human Labor and Preterm Birthmentioning

confidence: 99%

“…In agreement with these processes, progesterone administration can prolong pregnancy beyond term in rodents, but not in humans (see below) or higher non-human primates. Using Laurasiatheria species as the outgroup of Euarchontoglires it was suggested that the common ancestor of primates and rodents gave birth after systemic progesterone withdrawal and the functional withdrawal mechanism evolved later in the primates (Nnamani et al, 2013). The disparate mechanisms of progesterone maintenance and withdrawal in the two clades are underpinned by differences in cellular and molecular regulation, which limits the usefulness of common laboratory rats and mice in modeling parturition in the human (Mitchell and Taggart, 2009).…”

Section: Guinea Pig Model Of Human Labor and Preterm Birthmentioning

confidence: 99%

Birth and Neonatal Transition in the Guinea Pig: Experimental Approaches to Prevent Preterm Birth and Protect the Premature Fetus

et al. 2018

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The guinea pig (Cavia porcellus) displays many features of gestational physiology that makes it the most translationally relevant rodent species. Progesterone production undergoes a luteal to placental shift as in human pregnancy with levels rising during gestation and with labor and delivery occurring without a precipitous decline in maternal progesterone levels. In contrast to other laboratory rodents, labor in guinea pigs is triggered by a functional progesterone withdrawal, which involves the loss of uterine sensitivity to progesterone like in women. In both species the amnion membrane is a major source of labor-inducing prostaglandins, which promote functional progesterone withdrawal by modifying myometrial progesterone receptor expression. These similar features appear to result from convergent evolution rather than closer evolutionally relationship to primates compared to other rodents. Nevertheless, the similarities in the production, metabolism and actions of progesterone and prostaglandins allow information gained in pregnant guinea pigs to be extended to pregnant women with confidence. This includes exploring the effects of pregnancy complications including growth restriction and the mechanisms by which stressful conditions increase the incidence of preterm labor. The relatively long gestation of the guinea pig and the maturity of the pups at birth particularly in brain development means that a greater proportion of brain development happens in utero. This allows adverse intrauterine conditions to make a sustained impact on the developing brain like in compromised human pregnancies. In addition, the brain is exposed to a protective neurosteroid environment in utero, which has been suggested to promote development in the guinea pig and the human. Moreover, in utero stresses that have been shown to adversely affect long term neurobehavioral outcomes in clinical studies, can be modeled successfully in guinea pigs. Overall, these parallels to the human have led to increasing interest in the guinea pig for translational studies of treatments and therapies that potentially improve outcomes following adverse events in pregnancy and after preterm birth.

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Evidence for independent evolution of functional progesterone withdrawal in primates and guinea pigs

Cited by 18 publications

References 63 publications

Immunobiology of Cervix Ripening

Immunobiology of Cervix Ripening

Genomics of Preterm Birth

Birth and Neonatal Transition in the Guinea Pig: Experimental Approaches to Prevent Preterm Birth and Protect the Premature Fetus

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