Case Report: Birth Outcome and Neurodevelopment in Placental Malaria Discordant Twins

Placental malaria induces a unique methylation profile associated with fetal growth restriction

Fetal growth restriction (FGR) is associated with perinatal death and adverse birth outcomes, as well as long-term complications, including increased childhood morbidity, abnormal neurodevelopment, and cardio-metabolic diseases in adulthood. Placental epigenetic reprogramming associated with FGR may mediate these long-term outcomes. Placental malaria (PM), characterized by sequestration of Plasmodium falciparum-infected erythrocytes in placental intervillous space, is the leading global cause of FGR, but its impact on placental epigenetics is unknown. We hypothesized that placental methylomic profiling would reveal common and distinct mechanistic pathways of non-malarial and PM-associated FGR. We analyzed placentas from a US cohort with no malaria exposure (n = 12) and a cohort from eastern Uganda, a region with a high prevalence of malaria (n = 12). From each site, 8 cases of FGR and 4 healthy controls were analyzed. PM was diagnosed by placental histopathology. We compared the methylation levels of over 850K CpGs of the placentas using Infinium MethylationEPIC v1 microarray. Non-malarial FGR was associated with 65 differentially methylated CpGs (DMCs), whereas PM-FGR was associated with 133 DMCs, compared to their corresponding controls without FGR. One DMC (cg16389901, located in the promoter region of BMP4) was commonly hypomethylated in both groups. We identified 522 DMCs between non-malarial FGR vs. PM-FGR placentas, independent of differing geographic location or cellular composition. Placentas with PM-associated FGR have distinct methylation profiles compared to placentas with non-malarial FGR, suggesting novel epigenetic reprogramming in response to malaria. Larger cohort studies are needed to determine the distinct long-term health outcomes in PM-associated FGR pregnancies.

Malaria in pregnancy and its potential impact on neurodevelopment in children: a systematic review

BACKGROUND

Malaria during pregnancy can have adverse effects on fetal development, but its impact on neurodevelopment remains unclear. Although some studies have explored the consequences of prenatal malaria, gaps persist due to inconsistencies in exposure timing, assessment methods, and study designs.

METHODS

This systematic review highlighted the gaps in six studies selected from an initial pool of 2029 articles, offering clearer insights into the neurodevelopmental outcomes of prenatal malaria exposure.

RESULTS

Studies from Uganda, Benin, Ghana, and Malawi show that malaria during pregnancy adversely impacts cognitive, motor, and behavioral development. Cognitive deficits were observed at 12 and 24 months, with some studies indicating long-term effects at 36 months. Motor development and language outcomes were variable, with language impairments linked to malaria acquired late in pregnancy.

CONCLUSIONS

The review identifies gaps in research, such as the role of asymptomatic infections, exposure timing, and malaria's interaction with maternal comorbidities like HIV. Potential mechanisms for neurodevelopmental deficits include placental dysfunction and inflammation impacting fetal brain development. However, methodological limitations, such as varying assessment tools and sample sizes, prevent conclusive evidence. The review calls for more longitudinal studies to understand the long-term effects of prenatal malaria better and guide interventions to improve child development in malaria-endemic regions.

IMPACT

Prenatal malaria exposure is linked to cognitive deficits, with potential long-term effects on motor and language development. Late pregnancy malaria may have a stronger impact on language development, highlighting the importance of exposure timing. Mechanisms such as placental dysfunction and inflammation may disrupt fetal brain development and contribute to neurodevelopmental deficits. Future studies should prioritize longitudinal research using advanced methodologies to better understand the long-term effects of prenatal malaria exposure on neurodevelopment.

Placental Malaria Induces a Unique Methylation Profile Associated with Fetal Growth Restriction

BACKGROUND

Fetal growth restriction (FGR) is associated with perinatal death and adverse birth outcomes, as well as long-term complications, including increased childhood morbidity, abnormal neurodevelopment, and cardio-metabolic diseases in adulthood. Placental epigenetic reprogramming associated with FGR may mediate these long-term outcomes. Placental malaria (PM), characterized by sequestration of Plasmodium falciparum-infected erythrocytes in placental intervillous space, is the leading global cause of FGR, but its impact on placental epigenetics is unknown. We hypothesized that placental methylomic profiling would reveal common and distinct mechanistic pathways of non-malarial and PM-associated FGR.

RESULTS

We analyzed placentas from a US cohort with no malaria exposure (n = 12) and a cohort from eastern Uganda, a region with a high prevalence of malaria (n = 12). From each site, 8 cases of FGR (defined as birth weight <10%ile for gestational age by Intergrowth-21 standard curves) and 4 healthy controls with normal weight were analyzed. PM was diagnosed by placental histopathology. We compared the methylation levels of over 850K CpGs of the placentas using Infinium MethylationEPIC v1 microarray. Non-malarial FGR was associated with 65 differentially methylated CpGs (DMCs), whereas PM-FGR was associated with 133 DMCs, compared to their corresponding controls without FGR. One DMC (cg16389901, located in the promoter region of BMP4) was commonly hypomethylated in both groups. We identified 522 DMCs between non-malarial FGR vs. PM-FGR placentas, which was independent of differing geographic location or cellular composition.

CONCLUSION

Placentas with PM-associated FGR have distinct methylation profiles as compared to placentas with non-malarial FGR, suggesting novel epigenetic reprogramming in response to malaria. Larger cohort studies are needed to determine the distinct long-term health outcomes in PM-associated FGR pregnancies.

M. S, N. SN, Shankar G, Tripathi PK, Kashyap H, Jain A, Anvikar A, Chalageri VH. Exploring the hidden mental health consequences of malaria beyond the fever

Malaria morbidity has various presentations and the focus now shifts to uncommon signs and symptoms of malaria infection such as cognitive impairment to address the morbidity when the mortality declines. About 50% of children admitted to hospitals due to malaria experience neurological complications due to factors like low blood sugar, inflammation, elevated pressure, decreased oxygen levels, and excitotoxicity. Malaria during pregnancy negatively also impacts children's cognitive, behavioral, and executive function leading to neurodevelopmental delay due to increased susceptibility which can significantly affect maternal and child health, leading to higher rates of underestimated factors like anxiety, depression, and PTSD. Despite having the world's second-largest tribal population, India's indigenous and tribal communities and their mental health are less explored and less understood. Western psychological tools and neurocognitive assessment tools are not universally applicable, thus necessitating the development of tailored tools to investigate psychological or neurocognitive impairment. This paper has illuminated the hidden mental health consequences of malaria infection, emphasizing the prevalence, nature, and implications of psychological distress among affected individuals. The findings underscore the importance of recognizing and addressing these psychological consequences in the holistic management and prevention of malaria and its mental health consequences.

Role of Human Twin Studies to Identify Genetic Linkage of Malaria Pathogenesis and Outcomes

Malaria remains a major public health challenge that needs attention, especially when the world is aiming at malaria elimination in the near future. It is crucial to understand the underlying genetic factors and epigenetics involved in malaria susceptibility and the dynamics of host immune responses that affect disease outcomes and relapses in Plasmodium vivax and Plasmodium ovale. Studies in newborn and adult twins can help in understanding the comparative roles of environmental and genetic factors on disease pathogenesis and outcome. These studies can help in providing insights into the factors responsible for malaria susceptibility, clinical presentation, responsiveness toward existing as well as candidate antimalarials, and even identification of novel therapeutic targets. The results and outcomes from twin studies can be further applied to the entire population. In the present manuscript, we analyze the available literature on malaria and human twins and discuss the significance and benefits of twin studies to help in better understanding malaria.

The Association among Malaria in Pregnancy, Neonatal inflammation, and Neurocognitive Development in a Cohort of Malawian Infants

Malaria in pregnancy (MIP) causes poor birth outcomes, but its impact on neurocognitive development has not been well characterized. Between 2012 and 2014, we enrolled 307 mother-infant pairs and monitored 286 infants for neurocognitive development using the Malawi Developmental Assessment Tool at 6, 12, and 24 months of age. MIP was diagnosed from peripheral blood and placental specimens. Cord blood cytokine levels were assessed for a subset of neonates. Predictors of neurodevelopment were examined using mixed-effect logistic regression for developmental delay. Among the participants, 78 mothers (25.4%) had MIP, and 45 infants (15.7%) experienced severe neurocognitive delay. MIP was not associated with differences in cord blood cytokine levels or neurocognitive development. Preterm birth, low birthweight, increasing maternal education level, and increasing interleukin 6 levels were associated significantly with delay. The results highlight the prevalence of severe delay and a need for broad access to early childhood support in this setting.

Neurocognitive outcomes in Malawian children exposed to malaria during pregnancy: An observational birth cohort study

BACKGROUND

Annually 125 million pregnancies are at risk of malaria infection. However, the impact of exposure to malaria in pregnancy on neurodevelopment in children is not well understood. We hypothesized that malaria in pregnancy and associated maternal immune activation result in neurodevelopmental delay in exposed offspring.

METHODS AND FINDINGS

Between April 2014 and April 2015, we followed 421 Malawian mother-baby dyads (median [IQR] maternal age: 21 [19, 28] years) who were previously enrolled (median [IQR] gestational age at enrollment: 19.7 [17.9, 22.1] weeks) in a randomized controlled malaria prevention trial with 5 or 6 scheduled assessments of antenatal malaria infection by PCR. Children were evaluated at 12, 18, and/or 24 months of age with cognitive tests previously validated in Malawi: the Malawi Developmental Assessment Tool (MDAT) and the MacArthur-Bates Communicative Development Inventories (MCAB-CDI). We assessed the impact of antenatal malaria (n [%] positive: 240 [57.3]), placental malaria (n [%] positive: 112 [29.6]), and maternal immune activation on neurocognitive development in children. Linear mixed-effects analysis showed that children exposed to antenatal malaria between 33 and 37 weeks gestation had delayed language development across the 2-year follow-up, as measured by MCAB-CDI (adjusted beta estimate [95% CI], -7.53 [-13.04, -2.02], p = 0.008). Maternal immune activation, characterized by increased maternal sTNFRII concentration, between 33 and 37 weeks was associated with lower MCAB-CDI language score (adjusted beta estimate [95% CI], -8.57 [-13.09, -4.06], p < 0.001). Main limitations of this study include a relatively short length of follow-up and a potential for residual confounding that is characteristic of observational studies.

CONCLUSIONS

This mother-baby cohort presents evidence of a relationship between malaria in pregnancy and neurodevelopmental delay in offspring. Malaria in pregnancy may be a modifiable risk factor for neurodevelopmental injury independent of birth weight or prematurity. Successful interventions to prevent malaria during pregnancy may reduce the risk of neurocognitive delay in children.

Associations Between Malaria in Pregnancy and Neonatal Neurological Outcomes: Malaria in Pregnancy and Neonatal Neurological Outcomes

OBJECTIVE

To compare neurological functioning of neonates born to mothers with and without malaria in pregnancy.

METHODS

Pregnant women presenting at Korle Bu Teaching Hospital, Ghana were recruited into this prospective observational study. Malaria exposure was determined by clinically-documented antenatal malaria infection; parasitemia in maternal, placental, or umbilical cord blood; or placental histology. Neurological functioning was assessed using the Hammersmith Neonatal Neurological Examination within 48 hours of birth. Performance was classified as "optimal" or "suboptimal" by subdomain and overall.

RESULTS

Between 21^st November 2018 and 10^th February 2019, 211 term-born neonates, of whom 27 (13%) were exposed to malaria, were included. In the reflexes subdomain, exposed neonates tended to score lower (adjusted mean difference: -0.34, 95% CI: -0.70-0.03) with increased risk (adjusted risk ratio: 1.63, 95% CI: 1.09-2.44) of suboptimal performance compared to unexposed neonates. There were no significant between-group differences in scores or optimality classification for the remaining subdomains and overall.

CONCLUSION

Malaria-exposed neonates had similar neurological functioning relative to unexposed neonates, with differences confined to the reflexes subdomain, suggesting potential underlying neurological immaturity or injury. Further studies are needed to confirm these findings and determine the significance of malaria in pregnancy on long-term neurological outcomes.

Establishing a conceptual framework of the impact of placental malaria on infant neurodevelopment

A novel conceptual framework to describe the relationship between placental malaria and adverse infant neurodevelopmental outcomes is proposed. This conceptual framework includes three distinct stages: (1) maternal and environmental risk factors for the development of placental malaria; (2) placental pathology and inflammation associated with placental malaria infection; and (3) postnatal impacts of placental malaria. The direct, indirect, and bidirectional effects of these risk factors on infant neurodevelopment across the three stages were critically examined. These factors ultimately culminate in an infant phenotype that not only leads to adverse birth outcomes, but also to increased risks of neurological, cognitive, and behavioural deficits that may impact the quality of life in this high-risk population. Multiple risk factors were identified in this conceptual framework; nonetheless, based on current evidence, a key knowledge gap is the uncertainty regarding which are the most important and how exactly they interact.