Nervous System Injury and Neuroimaging of Zika Virus Infection

Long-term impact of congenital Zika virus infection on the rat hippocampus: Neuroinflammatory, glial alterations and sex-specific effects

Congenital Zika Syndrome (CZS) is a condition that arises when a neonate presents with abnormalities resulting from Zika virus infection during gestation. While microcephaly is a prominent feature of the syndrome, other forms of brain damage are also observed, often accompanied by significant neurological complications. It is therefore essential to investigate the long-term effects of CZS, with special attention to sex differences, particularly concerning hippocampal function, given its vulnerability to viral infections. The aim of this study was to evaluate the long-term impacts on cognitive and memory functions, as well as neuroinflammatory and glial alterations in the hippocampus, in offspring of both sexes exposed to a model of congenital Zika virus infection. Pregnant rats were subcutaneously inoculated with ZIKV-BR at a dose of 1 × 10^7 plaque-forming units (PFU mL^-1) of ZIKV isolated in Brazil (ZIKV-BR) on gestational day 18 (G18). From postnatal day 70, the animals underwent behavioral tests. On postnatal day 80, the animals were euthanized, and hippocampal samples were collected for biochemical and histological analyses. In the open field test, females displayed more exploratory behavior and less grooming, while no significant differences in locomotion were observed between the sexes. Additionally, ZIKV-exposed females showed a reduction in grooming behavior compared to ZIKV-exposed males. In the memory test, males in the ZIKV group exhibited greater memory impairment, spending more time to locate the correct quadrant, while females showed relatively better performance. Neuroinflammatory markers, such as TNF-α, were significantly elevated in the hippocampus of ZIKV-exposed animals, regardless of sex. However, microglial and astrocytic responses, indicated by higher IBA1 and GFAP density, were only observed in male ZIKV rats. In conclusion, our findings suggest that congenital ZIKV exposure leads to sex-specific behavioral and neuroinflammatory alterations. While both males and females exhibited some behavioral changes, males were more significantly impacted in memory performance. Additionally, increased neuroinflammatory markers and glial activation were observed in the hippocampus of ZIKV-exposed animals, with a pronounced response in males. These results highlight the long-term impact of ZIKV infection on neurodevelopment, emphasizing the importance of considering sex differences in studies of congenital ZIKV syndrome.

Characterizing the microstructural transition at the gray matter-white matter interface: Implementation and demonstration of age-associated differences

BACKGROUND

The cortical gray matter-white matter interface (GWI) is a natural transition zone where the composition of brain tissue abruptly changes and is a location for pathologic change in brain disorders. While diffusion magnetic resonance imaging (dMRI) is a reliable and well-established technique to characterize brain microstructure, the GWI is difficult to assess with dMRI due to partial volume effects and is normally excluded from such studies.

METHODS

In this study, we introduce an approach to characterize the dMRI microstructural profile across the GWI and to assess the sharpness of the microstructural transition from cortical gray matter (GM) to white matter (WM). This analysis includes cross-sectional data from a total of 146 participants (18-91 years; mean age: 52.4 (SD 21.4); 83 (57 %) female) enrolled in two normative lifespan cohorts at Albert Einstein College of Medicine from 2019 to 2023. We compute the aggregate GWI slope for each parameter, across each of 6 brain regions (cingulate, frontal, occipital, orbitofrontal, parietal, and temporal) for each participant. The association of GWI slope in each region with age was assessed using a linear model, with biological sex as a covariate.

RESULTS

We demonstrate this method captures an inherent change in fractional anisotropy (FA), axial diffusivity (AD), orientation dispersion index (ODI) and intracellular volume fraction (ICVF) across the GWI that is characterized by small variance. We identified statistically significant associations of FA slope with age in all regions (p < 0.002 for all analyses), with FA slope magnitude inversely associated with higher age. Similar statistically significant age-related associations were found for AD slope in cingulate, occipital, and temporal regions, for ODI slope in parietal and occipital regions, and for ICVF slope in frontal, orbitofrontal, parietal, and temporal regions.

CONCLUSION

The inverse association of slope magnitude with age indicates loss of the sharp GWI transition in aging, which is consistent with processes such as dendritic pruning, axonal degeneration, and inflammation. This method overcomes techniques issues related to interrogating the GWI. Beyond characterizing normal aging, it could be applied to explore pathological effects at this crucial, yet under-researched region.

Association between Sleep and Language Development in Children with Congenital Zika Syndrome

AIM

Congenital Zika Virus Syndrome (CZS) presents notable hurdles to neurodevelopment, with language development emerging as a crucial aspect. This study investigates sleep patterns and language skills in children with CZS, aiming to explore the potential synchronization of sleep development with their neurodevelopment.

METHOD

We studied cross-sectionally 135 children with CZS aged 0 to 48 months, investigating sleep using the BISQ Questionnaire. Language development was assessed using the Early Language Milestone Scale, while motor development and cognitive and social ability were assessed using the Bayley Scales of Infant and Young Child Development 3rd edition. We also studied longitudinally a cohort of 16 children (initially aged 0 to 12 months) whom we followed for four years, assessing at one-year intervals.

RESULTS

Sleep disturbances and language deficits were highly frequent in this population. In the 0-12 months group, a late bedtime and frequent nighttime awakenings were associated with poorer auditory expressive skills. At 13-24 months, nighttime awakenings were associated with poorer auditory expressive skills, while among 25-36-month-olds decreased auditory receptive skills were associated with longer sleep onset latency and reduced nighttime sleep duration.

CONCLUSION

The brain alterations caused by Zika virus infection affect both sleep disturbances and delays in language development. It is possible that sleep disturbance may be a mediating factor in the pathway between CZS and delayed language development, as the three analyzed language skills showed a correlation with sleep parameters.

Zika virus in India: past, present and future

Zika virus (ZIKV) is an arthropod-borne flavivirus that presents with acute febrile illness associated with rash, arthralgia and conjunctivitis. After years of sporadic reports in Africa, the three major outbreaks of this disease occurred in Yap Islands (2007), French Polynesia (2013-14) and South Americas (2015-16). Although, serological surveys suggested the presence of ZIKV in India in 1950s, cross-reactivity could not be ruled out. The first four proven cases of ZIKV from India were reported in 2017. This was followed by major outbreaks in the states of Rajasthan and Madhya Pradesh in 2018. Fortunately, the outbreaks in India were not associated with neurological complications. These outbreaks in India highlighted the spread of this disease beyond geographical barriers owing to the growing globalization, increased travel and ubiquitous presence of its vector, the Aedes mosquito. In this review, we discuss the epidemiology, clinical features and management of ZIKV in India.

Zika virus NS1 suppresses VE-cadherin via hsa-miR-29b-3p/DNMT3b/MMP-9 pathway in human brain microvascular endothelial cells

Zika virus infection has been reported to cause microcephaly in newborns. ZIKV exploits various strategies to cross the blood-brain barrier. ZIKV NS1 may compromise the barrier integrity of endothelial cells by regulating expression of junctional proteins. MicroRNAs play an important role in post-transcriptional gene regulations. We demonstrated that ZIKV-NS1 affected the adherence junction protein in human brain microvascular endothelial cells via hsa-miR-29b-3p/DNMT3b/MMP-9 pathway. The hCMEC/D3 cells were exposed to ZIKV-NS1 with different doses (500 ng/mL and 1000 ng/mL) for 24 h. The expression pattern of DNTM3b, MMP-9, and VE-cadherin were studied using immunoblotting and the distribution of DNMT3b and MMP-9 were studied using immunofluorescence. The quantification of hsa-miR-29b-3p was done through qRT-PCR. Direct regulation of DNMT3b by hsa-miR-29b-3p was demonstrated by overexpression of hsa-miR-29b-3p using hsa-miR-29b-3p mimic, and knockdown of hsa-miR-29b-3p by using hsa-miR-29b-3p inhibitors. The ZIKV-NS1 affected the barrier function of endothelial cells through the increased expression of hsa-miR29b-3p, which suppressed the DNMT3b, thus enhanced expression of MMP-9, which finally suppressed the expression of VE-cadherin. These findings suggested that ZIKV-NS1 alters the expression of Adherens Junction protein in human brain microvascular endothelial cells through hsa-miR-29b-3p/DNMT3b/MMP-9 pathway, which compromised the barrier function of human brain microvascular endothelial cells.

The role of glial cells in Zika virus-induced neurodegeneration

Zika virus (ZIKV) is a strongly neurotropic flavivirus whose infection has been associated with microcephaly in neonates. However, clinical and experimental evidence indicate that ZIKV also affects the adult nervous system. In this regard, in vitro and in vivo studies have shown the ability of ZIKV to infect glial cells. In the central nervous system (CNS), glial cells are represented by astrocytes, microglia, and oligodendrocytes. In contrast, the peripheral nervous system (PNS) constitutes a highly heterogeneous group of cells (Schwann cells, satellite glial cells, and enteric glial cells) spread through the body. These cells are critical in both physiological and pathological conditions; as such, ZIKV-induced glial dysfunctions can be associated with the development and progression of neurological complications, including those related to the adult and aging brain. This review will address the effects of ZIKV infection on CNS and PNS glial cells, focusing on cellular and molecular mechanisms, including changes in the inflammatory response, oxidative stress, mitochondrial dysfunction, Ca²⁺ and glutamate homeostasis, neural metabolism, and neuron-glia communication. Of note, preventive and therapeutic strategies that focus on glial cells may emerge to delay and/or prevent the development of ZIKV-induced neurodegeneration and its consequences.

Nucleolar stress: From development to cancer

The nucleolus is a large nuclear membraneless organelle responsible for ribosome biogenesis. Ribosomes are cytoplasmic macromolecular complexes comprising RNA and proteins that link amino acids together to form new proteins. The biogenesis of ribosomes is an intricate multistep process that involves the transcription of ribosomal DNA (rDNA), the processing of ribosomal RNA (rRNA), and the assembly of rRNA with ribosomal proteins to form active ribosomes. Nearly all steps necessary for ribosome production and maturation occur in the nucleolus. Nucleolar shape, size, and number are directly linked to ribosome biogenesis. Errors in the steps of ribosomal biogenesis are sensed by the nucleolus causing global alterations in nucleolar function and morphology. This phenomenon, known as nucleolar stress, can lead to molecular changes such as stabilization of p53, which in turn activates cell cycle arrest or apoptosis. In this review, we discuss recent work on the association of nucleolar stress with degenerative diseases and developmental defects. In addition, we highlight the importance of de novo nucleotide biosynthesis for the enhanced nucleolar activity of cancer cells and discuss targeting nucleotide biosynthesis as a strategy to activate nucleolar stress to specifically target cancer cells.

Diagnostic accuracy of prenatal imaging for the diagnosis of congenital Zika syndrome: Systematic review and meta-analysis

Objective

The aim of this study was to assess the accuracy of prenatal imaging for the diagnosis of congenital Zika syndrome.

Data sources

Medline (via Pubmed), PubMed, Scopus, Web of Science, and Google Scholar from inception to March 2022. Two researchers independently screened study titles and abstracts for eligibility.

Study eligibility criteria

Observational studies with Zika virus-infected pregnant women were included. The index tests included ultrasound and/or magnetic resonance imaging. The reference standard included (1) Zika infection-related perinatal death, stillbirth, and neonatal death within the first 48 h of birth, (2) neonatal intensive care unit admission, and (3) clinically defined adverse perinatal outcomes.

Synthesis methods

We extracted 2 × 2 contingency tables. Pooled sensitivity and specificity were estimated using the random-effects bivariate model and assessed the summary receiver operating characteristic (ROC) curve. Risk of bias was assessed using QUADAS 2 tool. The certainty of the evidence was evaluated with grading of recommendations.

Results

We screened 1,459 references and included 18 studies (2359 pregnant women, 347 fetuses with confirmed Zika virus infection). Twelve studies (67%) were prospective cohorts/case series, and six (37%) were retrospective cohort/case series investigations. Fourteen studies (78%) were performed in endemic regions. Ten studies (56%) used prenatal ultrasound only, six (33%) employed ultrasound and fetal MRI, and two studies (11%) used prenatal ultrasound and postnatal fetal MRI. A total of six studies (ultrasound only) encompassing 780 pregnant women (122 fetuses with confirmed Zika virus infection) reported relevant data for meta-analysis (gestation age at which ultrasound imagining was captured ranged from 16 to 34 weeks). There was large heterogeneity across studies regarding sensitivity (range: 12 to 100%) and specificity (range: 50 to 100%). Under a random-effects model, the summary sensitivity of ultrasound was 82% (95% CI, 19 to 99%), and the summary specificity was 97% (71 to 100%). The area under the ROC curve was 97% (95% CI, 72 to 100%), and the summary diagnostic odds ratio was 140 (95% CI, 3 to 7564, P < 0.001). The overall certainty of the evidence was "very low".

Conclusion

Ultrasound may be useful in improving the diagnostic accuracy of Zika virus infection in pregnancy. However, the evidence is still substantially uncertain due to the methodological limitations of the available studies. Larger, properly conducted diagnostic accuracy studies of prenatal imaging for the diagnosis of congenital Zika syndrome are warranted.

Systematic review registration

Identifier [CRD42020162914].

A Rat Model of Prenatal Zika Virus Infection and Associated Long-Term Outcomes

Zika virus (ZIKV) is a mosquito-borne flavivirus that became widely recognized due to the epidemic in Brazil in 2015. Since then, there has been nearly a 20-fold increase in the incidence of microcephaly and birth defects seen among women giving birth in Brazil, leading the Centers for Disease Control and Prevention (CDC) to officially declare a causal link between prenatal ZIKV infection and the serious brain abnormalities seen in affected infants. Here, we used a unique rat model of prenatal ZIKV infection to study three possible long-term outcomes of congenital ZIKV infection: (1) behavior, (2) cell proliferation, survival, and differentiation in the brain, and (3) immune responses later in life. Adult offspring that were prenatally infected with ZIKV exhibited motor deficits in a sex-specific manner, and failed to mount a normal interferon response to a viral immune challenge later in life. Despite undetectable levels of ZIKV in the brain and serum in these offspring at P2, P24, or P60, these results suggest that prenatal exposure to ZIKV results in lasting consequences that could significantly impact the health of the offspring. To help individuals already exposed to ZIKV, as well as be prepared for future outbreaks, we need to understand the full spectrum of neurological and immunological consequences that could arise following prenatal ZIKV infection.

Accessible pediatric neuroimaging using a low field strength MRI scanner

Magnetic resonance imaging (MRI) has played an increasingly relevant role in understanding infant, child, and adolescent neurodevelopment, providing new insight into developmental patterns in neurotypical development, as well as those associated with potential psychopathology, learning disorders, and other neurological conditions. In addition, studies have shown the impact of a child's physical and psychosocial environment on developing brain structure and function. A rate-limiting complication in these studies, however, is the high cost and infrastructural requirements of modern MRI systems. High costs mean many neuroimaging studies typically include fewer than 100 individuals and are performed predominately in high resource hospitals and university settings within high income countries (HICs). As a result, our knowledge of brain development, particularly in children who live in lower and middle income countries (LMICs) is relatively limited. Low field systems, with magnetic fields less than 100mT offer the promise of lower scanning costs and wide-spread global adoption, but routine low field pediatric neuroimaging has yet to be demonstrated. Here we present the first pediatric MRI data collected on a low cost and assessable 64mT scanner in children 6 weeks to 16 years of age and replicate brain volumes estimates and developmental trajectories derived from 3T MRI data. While preliminary, these results illustrate the potential of low field imaging as a viable complement to more conventional high field imaging systems, and one that may further enhance our knowledge of neurodevelopment in LMICs where malnutrition, psychosocial adversities, and other environmental exposures may profoundly affect brain maturation.

Gist of Zika Virus pathogenesis

Zika virus (ZIKV) is a mosquito-borne neurotropic flavivirus. ZIKV infection may lead to microcephaly in developing fetus and Guillain-Barré Syndrome (GBS) like symptoms in adults. ZIKV was first reported in humans in 1952 from Uganda and the United Republic of Tanzania. Later, ZIKV outbreak was reported in 2007 from the Yap Island. ZIKV re-emerged as major outbreak in the year 2013 from French Polynesia followed by second outbreak in the year 2015 from Brazil. ZIKV crosses the blood-tissue barriers to enter immune-privileged organs. Clinical manifestations in ZIKV disease includes rash, fever, conjunctivitis, muscle and joint pain, headache, transverse myelitis, meningoencephalitis, Acute Disseminated Encephalomyelitis (ADEM). The understanding of the molecular mechanism of ZIKV pathogenesis is very important to develop potential diagnostic and therapeutic interventions for ZIKV infected patients.

Advanced "lab-on-a-chip" to detect viruses - Current challenges and future perspectives

Massive viral outbreaks draw attention to viruses that have not been thoroughly studied or understood. In recent decades, microfluidic chips, known as "lab-on-a-chip", appears as a promising tool for the detection of viruses. Here, we review the development of microfluidic chips that could be used in response to viral detection, specifically for viruses involved in more recent outbreaks. The advantages as well as the disadvantages of microfluidic systems are discussed and analyzed. We also propose ideas for future development of these microfluidic chips and we expect this advanced technology to be used in the future for viral outbreaks.

COVID-19-Associated Bifacial Weakness with Paresthesia Subtype of Guillain-Barré Syndrome

We report a case of bifacial weakness with paresthesia, a recognized Guillain-Barré syndrome subtype characterized by rapidly progressive facial weakness and paresthesia without ataxia or other cranial neuropathies, which was temporally associated with antecedent coronavirus 2019 (COVID-19). This case highlights a potentially novel but critically important neurologic association of the COVID-19 disease process. Herein, we detail the clinicoradiologic work-up and diagnosis, clinical course, and multidisciplinary medical management of this patient with COVID-19. This case is illustrative of the increasingly recognized but potentially underreported neurologic manifestations of COVID-19, which must be considered and further investigated in this pandemic disease.

Transfusion-Transmitted Zika Virus Infection in Pregnant Mice Leads to Broad Tissue Tropism With Severe Placental Damage and Fetal Demise

Zika virus (ZIKV) infection during pregnancy can cause significant problems, particularly congenital Zika syndrome. Nevertheless, the potential deleterious consequences and associated mechanisms of transfusion-transmitted ZIKV infection on pregnant individuals and their fetuses and babies have not been investigated. Here we examined transmissibility of ZIKV through blood transfusion in ZIKV-susceptible pregnant A129 mice. Our data showed that transfused-transmitted ZIKV at the early infection stage led to significant viremia and broad tissue tropism in the pregnant recipient mice, which were not seen in those transfused with ZIKV-positive (ZIKV⁺) plasma at later infection stages. Importantly, pregnant mice transfused with early-stage, but not later stages, ZIKV⁺ plasma also exhibited severe placental infection with vascular damage and apoptosis, fetal infection and fetal damage, accompanied by fetal and pup death. Overall, this study suggests that transfusion-related transmission of ZIKV during initial stage of infection, which harbors high plasma viral titers, can cause serious adverse complications in the pregnant recipients and their fetuses and babies.

Association of Infants Exposed to Prenatal Zika Virus Infection With Their Clinical, Neurologic, and Developmental Status Evaluated via the General Movement Assessment Tool

IMPORTANCE

There is an urgent need to assess neurodevelopment in Zika virus (ZIKV)-exposed infants.

OBJECTIVES

To perform general movement assessment (GMA) at 9 to 20 weeks' postterm age and to evaluate whether the findings are associated with neurodevelopmental outcomes at age 12 months in infants prenatally exposed to acute maternal illness with rash in Brazil during the ZIKV outbreak and in age-matched controls.

DESIGN, SETTING, AND PARTICIPANTS

In this cohort study, infants prenatally exposed to acute maternal illness with rash were recruited at medical institutions in Rio de Janeiro and Belo Horizonte, Brazil, from February 1, 2016, to April 30, 2017, while infants without any exposure to maternal illness originated from the Graz University Audiovisual Research Database for the Interdisciplinary Analysis of Neurodevelopment. Participants were 444 infants, including 76 infants without congenital microcephaly, 35 infants with microcephaly, and 333 neurotypical children matched for sex, gestational age at birth, and age at GMA.

MAIN OUTCOMES AND MEASURES

General movement assessment performed at 9 to 20 weeks' postterm age, with negative predictive value, positive predictive value, sensitivity, and specificity generated, as well as clinical, neurologic, and developmental status (Bayley Scales of Infant and Toddler Development, Third Edition [Bayley-III] scores) at age 12 months. Motor Optimality Scores were generated based on the overall quality of the motor repertoire. Adverse outcomes were defined as a Bayley-III score less than 2 SD in at least 1 domain, a score less than 1 SD in at least 2 domains, and/or atypical neurologic findings.

RESULTS

A total of 444 infants were enrolled, including 111 children prenatally exposed to a maternal illness with rash and 333 children without any prenatal exposure to maternal illness (57.7% male and mean [SD] age, 14 [2] weeks for both groups); 82.1% (46 of 56) of ZIKV-exposed infants without congenital microcephaly were healthy at age 12 months. Forty-four of 46 infants were correctly identified by GMA at 3 months, with a negative predictive value of 94% (95% CI, 85%-97%). Seven of 10 ZIKV-exposed children without microcephaly with adverse neurodevelopmental outcomes were identified by GMA. The GMA positive predictive value was 78% (95% CI, 46%-94%), sensitivity was 70% (95% CI, 35%-93%), specificity was 96% (95% CI, 85%-99%), and accuracy was 91% (95% CI, 80%-97%). Children with microcephaly had bilateral spastic cerebral palsy; none had normal movements. The Motor Optimality Score differentiated outcomes: the median Motor Optimality Score was 23 (interquartile range [IQR], 21-26) in children with normal development, 12 (IQR, 8-19) in children with adverse outcomes, and 5 (IQR, 5-6) in children with microcephaly, a significant difference (P = .001).

CONCLUSIONS AND RELEVANCE

This study suggests that although a large proportion of ZIKV-exposed infants without microcephaly develop normally, many do not. The GMA should be incorporated into routine infant assessments to enable early entry into targeted treatment programs.