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Evolution, Medicine, and Public Health
Number of Followers: 10 ![]() ISSN (Online) 2050-6201 Published by Oxford University Press ![]() |
- Host–gut microbiota interactions during pregnancy
Pages: 7 - 23
Abstract: AbstractMammalian pregnancy is characterized by a well-known suite of physiological changes that support fetal growth and development, thereby positively affecting both maternal and offspring fitness. However, mothers also experience trade-offs between current and future maternal reproductive success, and maternal responses to these trade-offs can result in mother–offspring fitness conflicts. Knowledge of the mechanisms through which these trade-offs operate, as well as the contexts in which they operate, is critical for understanding the evolution of reproduction. Historically, hormonal changes during pregnancy have been thought to play a pivotal role in these conflicts since they directly and indirectly influence maternal metabolism, immunity, fetal growth and other aspects of offspring development. However, recent research suggests that gut microbiota may also play an important role. Here, we create a foundation for exploring this role by constructing a mechanistic model linking changes in maternal hormones, immunity and metabolism during pregnancy to changes in the gut microbiota. We posit that marked changes in hormones alter maternal gut microbiome composition and function both directly and indirectly via impacts on the immune system. The gut microbiota then feeds back to influence maternal immunity and metabolism. We posit that these dynamics are likely to be involved in mediating maternal and offspring fitness as well as trade-offs in different aspects of maternal and offspring health and fitness during pregnancy. We also predict that the interactions we describe are likely to vary across populations in response to maternal environments. Moving forward, empirical studies that combine microbial functional data and maternal physiological data with health and fitness outcomes for both mothers and infants will allow us to test the evolutionary and fitness implications of the gestational microbiota, enriching our understanding of the ecology and evolution of reproductive physiology.
PubDate: Sat, 06 Jan 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae001
Issue No: Vol. 12, No. 1 (2024)
- Evolutionary and empirical perspectives on ‘demand’ breastfeedingThe
baby in the driver’s seat or the back seat'
Pages: 24 - 32
Abstract: AbstractBackground/ObjectivesThe concept of ‘demand’ breastfeeding is central in public health. A key feature of the concept is that the infant is the locus of control in the breastfeeding process; when the breast is demanded by the infant, it is given the opportunity to feed. This study questions this notion of the infant as the locus of control in demand breastfeeding for empirical and theoretical reasons. From an evolutionary perspective, infants are expected to seek maximal investment and, against this backdrop of maximal investment-seeking, parents decide how much investment to put into offspring.MethodologyFocal follows were conducted among 113 mother–infant dyads in Papua New Guinea. During these follows, response times and types of responses, including breastfeeding to offspring fussing and crying, were recorded.ResultsInfants were breastfed an average of 3.6 times/hour for just over 2 min/feed. Fussing and crying were responded to quickly, with most response times under 1 min. When the mother responded, she breastfed the child approximately 52% of the time. The other 48% of the time, mothers responded to infants with other forms of pacification. Mothers were significantly less likely to respond to infants by breastfeeding if the child had been breastfed within the past 59–76 min.Conclusion/ImplicationsAs predicted by evolutionary parental investment theory, infants make frequent demands on their parents for investment, but mothers are ultimately the locus of control in the investment process. The mother decides whether and how frequently to breastfeed her offspring against this backdrop of near-continuous investment demands.
PubDate: Sat, 20 Jan 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae003
Issue No: Vol. 12, No. 1 (2024)
- Could care giving have altered the evolution of human immune
strategies'
Pages: 33 - 49
Abstract: AbstractLife history theory indicates that individuals/species with a slow pace of life invest more in acquired than innate immunity. Factors that decrease the pace of life and predict greater investment in acquired immunity include increased nutritional resources, increased pathogen exposure and decreased risk of extrinsic mortality. Common care behaviors given to sick individuals produce exactly these effects: provisioning increases nutritional resources; hygiene assistance increases disease exposure of carers; and protection can reduce the risk of extrinsic mortality to sick individuals. This study, therefore, investigated under what conditions care giving behaviors might impact immune strategy and pace of life. The study employed an agent-based model approach that simulated populations with varying levels of care giving, disease mortality, disease transmissibility, and extrinsic mortality, enabling measurements of how the immune strategy and age structure of the populations changed over evolutionary time. We used multiple regressions to examine the effects of these variables on immune strategy and the age structure of the population. The findings supported our predictions that care was selected for an acquired immunity. However, the pace of life did not slow as expected. Instead, the population shifted to a faster, but also more cost-intensive reproductive strategy in which care improved child survival by subsidizing the development of acquired immune responses.
PubDate: Thu, 25 Jan 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae004
Issue No: Vol. 12, No. 1 (2024)
- Reconsidering the developmental origins of adult disease paradigmThe
‘metabolic coordination of childbirth’ hypothesis
Pages: 50 - 66
Abstract: AbstractIn uncomplicated pregnancies, birthweight is inversely associated with adult non-communicable disease (NCD) risk. One proposed mechanism is maternal malnutrition during pregnancy. Another explanation is that shared genes link birthweight with NCDs. Both hypotheses are supported, but evolutionary perspectives address only the environmental pathway. We propose that genetic and environmental associations of birthweight with NCD risk reflect coordinated regulatory systems between mother and foetus, that evolved to reduce risks of obstructed labour. First, the foetus must tailor its growth to maternal metabolic signals, as it cannot predict the size of the birth canal from its own genome. Second, we predict that maternal alleles that promote placental nutrient supply have been selected to constrain foetal growth and gestation length when fetally expressed. Conversely, maternal alleles that increase birth canal size have been selected to promote foetal growth and gestation when fetally expressed. Evidence supports these hypotheses. These regulatory mechanisms may have undergone powerful selection as hominin neonates evolved larger size and encephalisation, since every mother is at risk of gestating a baby excessively for her pelvis. Our perspective can explain the inverse association of birthweight with NCD risk across most of the birthweight range: any constraint of birthweight, through plastic or genetic mechanisms, may reduce the capacity for homeostasis and increase NCD susceptibility. However, maternal obesity and diabetes can overwhelm this coordination system, challenging vaginal delivery while increasing offspring NCD risk. We argue that selection on viable vaginal delivery played an over-arching role in shaping the association of birthweight with NCD risk.
PubDate: Thu, 18 Jan 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae002
Issue No: Vol. 12, No. 1 (2024)
- A multi-million-year natural experimentComparative genomics on a massive
scale and its implications for human health
Pages: 67 - 70
Abstract: AbstractImproving the diversity and quality of genome assemblies for non-human mammals has been a long-standing goal of comparative genomics. The last year saw substantial progress towards this goal, including the release of genome alignments for 240 mammals and nearly half the primate order. These resources have increased our ability to identify evolutionarily constrained regions of the genome, and together strongly support the importance of these regions to biomedically relevant trait variation in humans. They also provide new strategies for identifying the genetic basis of changes unique to individual lineages, illustrating the value of evolutionary comparative approaches for understanding human health.
PubDate: Wed, 03 Apr 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae006
Issue No: Vol. 12, No. 1 (2024)
- Introduction to the special issue: evolutionary and biopsychosocial
perspectives on sickness communication
Pages: 71 - 74
Abstract: AbstractHere, we introduce the EMPH special issue on Evolutionary and Biopsychosocial Perspectives on Sickness Communication. This Commentary provides an overview of each article and places them in the wider context of sickness as a social phenomenon with verbal and nonverbal signals. This Commentary, and the special issue, in general, calls for greater attention to these signals that can affect pathogen transmission and may be at the evolutionary root of our caregiving systems and behaviours.
PubDate: Mon, 25 Mar 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae005
Issue No: Vol. 12, No. 1 (2024)
- Nausea, vomiting and conflict in pregnancyThe adaptive significance of
Growth-Differentiation Factor 15
Pages: 75 - 81
Abstract: AbstractNausea and vomiting in pregnancy (NVP) is heritable, common and aversive, and its extreme, hyperemesis gravidarum (HG), can be highly deleterious to the mother and fetus. Recent influential studies have demonstrated that HG is caused predominantly by high levels of Growth-Differentiation Factor 15 (GDF15), a hormone produced by the placenta in substantial amounts. This work has led to calls for therapeutic modulation of this hormone to reduce GDF15 levels and ameliorate HG risk. I describe three main lines of evidence relevant to the hypothesis that GDF15 production is typically adaptive for the fetus, in the context of enhanced placental invasion, reduced rates of miscarriage and preterm birth and higher birth weight. These considerations highlight the medical implications of maternal-fetal conflict, in the context of tradeoffs between aversive symptoms during gestation, rare disorders of pregnancy with major adverse effects and moderate fitness-enhancing benefits to fetuses.
PubDate: Tue, 23 Apr 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae008
Issue No: Vol. 12, No. 1 (2024)
- Senolytics and cell senescence: historical and evolutionary perspectives
Pages: 82 - 85
Abstract: AbstractSenolytics are a new class of anti-aging drugs developed to selectively kill ‘senescent’ cells that are considered harmful in normal aging. More than 20 drug trials are ongoing with diverse ‘senolytic cocktails’. This commentary on recent reviews of senolytics gives a historical context of mammalian cell senescence that enabled these new drugs. While cell senescence is considered harmful to aging tissues, many studies show its essential role in some regenerative and developmental processes for which senolytic drugs may interfere. Longer-term studies of side effects are needed before senolytics are considered for general clinical practice. The wide occurrence of cell senescence in eukaryotes, yeast to fish to humans, and suggests an ancient eukaryotic process that evolved multiple phenotypes.
PubDate: Fri, 03 May 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae007
Issue No: Vol. 12, No. 1 (2024)
- The Uncontrollable Mortality Risk HypothesisTheoretical foundations and
implications for public health
Pages: 86 - 96
Abstract: AbstractThe ‘Uncontrollable Mortality Risk Hypothesis’ employs a behavioural ecological model of human health behaviours to explain the presence of social gradients in health. It states that those who are more likely to die due to factors beyond their control should be less motivated to invest in preventative health behaviours. We outline the theoretical assumptions of the hypothesis and stress the importance of incorporating evolutionary perspectives into public health. We explain how measuring perceived uncontrollable mortality risk can contribute towards understanding socioeconomic disparities in preventative health behaviours. We emphasize the importance of addressing structural inequalities in risk exposure, and argue that public health interventions should consider the relationship between overall levels of mortality risk and health behaviours across domains. We suggest that measuring perceptions of uncontrollable mortality risk can capture the unanticipated health benefits of structural risk interventions, as well as help to assess the appropriateness of different intervention approaches.
PubDate: Thu, 09 May 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae009
Issue No: Vol. 12, No. 1 (2024)
- Re-examining the adaptive function of nausea and vomiting in pregnancy
Pages: 97 - 104
Abstract: ABSTRACTNausea and vomiting in pregnancy (NVP) have been proposed to have a prophylactic function. In this review, I re-examine NVP from an evolutionary perspective in light of new research on NVP. First, current evidence suggests that the observed characteristics of NVP does not align well with a prophylactic function. Further, NVP is typically associated with high costs for pregnant women, while moderate-to-severe NVP is associated with increased risks of poorer foetal/birth outcomes. In contrast, mild NVP limited to early pregnancy may associate with improved foetal outcomes—indicating a potential evolutionary benefit. Second, researchers have recently identified growth differentiation factor 15 (GDF15) to cause NVP, with implications that low-levels of pre-conception GDF15 (associated with lower cellular stress/inflammation) may increase risks/symptoms of NVP. If so, NVP in contemporary post-industrialized populations may be more severe due to environmental mismatch, and the current symptomology of NVP in such populations should not be viewed as a typical experience of pregnancy.
PubDate: Tue, 02 Jul 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae012
Issue No: Vol. 12, No. 1 (2024)
- Life history traits and cancer prevalence in birds
Pages: 105 - 116
Abstract: ABSTRACTBackground and objectivesCancer is a disease that affects nearly all multicellular life, including the broad and diverse taxa of Aves. While little is known about the factors that contribute to cancer risk across Aves, life history trade-offs may explain some of this variability in cancer prevalence. We predict birds with high investment in reproduction may have a higher likelihood of developing cancer. In this study, we tested whether life history traits are associated with cancer prevalence in 108 species of birds.MethodologyWe obtained life history data from published databases and cancer data from 5,729 necropsies from 108 species of birds across 24 taxonomic orders from 25 different zoological facilities. We performed phylogenetically controlled regression analyses between adult body mass, lifespan, incubation length, clutch size, sexually dimorphic traits, and both neoplasia and malignancy prevalence. We also compared the neoplasia and malignancy prevalence of female and male birds.ResultsProviding support for a life history trade-off between somatic maintenance and reproduction, we found a positive relationship between clutch size and cancer prevalence across Aves. There was no significant association with body mass, lifespan, incubation length, sexual dimorphism, and cancer.Conclusions and implicationsLife history theory presents an important framework for understanding differences in cancer defenses across various species. These results suggest a trade-off between reproduction and somatic maintenance, where Aves with small clutch sizes get less cancer.
PubDate: Thu, 27 Jun 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae011
Issue No: Vol. 12, No. 1 (2024)
- Advancing evolutionary medicine in Northern GermanyCollaboration between
Kiel University’s Medical Faculty and the Max Planck Institute for
Evolutionary Biology
Pages: 117 - 121
Abstract: German Science FoundationClinician Scientist Program in Evolutionary MedicineBA 2863/9-1BA 2863/9-2
PubDate: Wed, 24 Jul 2024 00:00:00 GMT
DOI: 10.1093/emph/eoae013
Issue No: Vol. 12, No. 1 (2024)
- Sperm intrusion into the implantation-stage blastocyst and its potential
biological significance
Pages: 1 - 6
Abstract: AbstractThe human embryo derives from fusion of oocyte and sperm, undergoes growth and differentiation, resulting in a blastocyst. To initiate implantation, the blastocyst hatches from the zona pellucida, allowing access from external inputs. Modelling of uterine sperm distribution indicates that 200–5000 sperm cells may reach the implantation-stage blastocyst following natural coitus. We show ultrastructural evidence of sperm cells intruding into trophectoderm cells of zona-free blastocysts obtained from the uterus of rhesus monkeys. Interaction between additional sperm and zona-free blastocyst could be an evolutionary feature yielding adaptive processes influencing the developmental fate of embryos. This process bears potential implications in pregnancy success, sperm competition and human health.
PubDate: Sat, 23 Dec 2023 00:00:00 GMT
DOI: 10.1093/emph/eoad043
Issue No: Vol. 12, No. 1 (2023)