Browsing by Subject "Cerebral malaria"
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Item A human pluripotent stem cell-derived in vitro model of the blood-brain barrier in cerebral malaria(Springer Nature, 2024-05-01) Gopinadhan, Adnan; Hughes, Jason M.; Conroy, Andrea L.; John, Chandy C.; Canfield, Scott G.; Datta, Dibyadyuti; Pediatrics, School of MedicineBackground: Blood-brain barrier (BBB) disruption is a central feature of cerebral malaria (CM), a severe complication of Plasmodium falciparum (Pf) infections. In CM, sequestration of Pf-infected red blood cells (Pf-iRBCs) to brain endothelial cells combined with inflammation, hemolysis, microvasculature obstruction and endothelial dysfunction mediates BBB disruption, resulting in severe neurologic symptoms including coma and seizures, potentially leading to death or long-term sequelae. In vitro models have advanced our knowledge of CM-mediated BBB disruption, but their physiological relevance remains uncertain. Using human induced pluripotent stem cell-derived brain microvascular endothelial cells (hiPSC-BMECs), we aimed to develop a novel in vitro model of the BBB in CM, exhibiting enhanced barrier properties. Methods: hiPSC-BMECs were co-cultured with HB3var03 strain Pf-iRBCs up to 9 h. Barrier integrity was measured using transendothelial electrical resistance (TEER) and sodium fluorescein permeability assays. Localization and expression of tight junction (TJ) proteins (occludin, zonula occludens-1, claudin-5), cellular adhesion molecules (ICAM-1, VCAM-1), and endothelial surface markers (EPCR) were determined using immunofluorescence imaging (IF) and western blotting (WB). Expression of angiogenic and cell stress markers were measured using multiplex proteome profiler arrays. Results: After 6-h of co-culture with Pf-iRBCs, hiPSC-BMECs showed reduced TEER and increased sodium fluorescein permeability compared to co-culture with uninfected RBCs, indicative of a leaky barrier. We observed disruptions in localization of occludin, zonula occludens-1, and claudin-5 by IF, but no change in protein expression by WB in Pf-iRBC co-cultures. Expression of ICAM-1 and VCAM-1 but not EPCR was elevated in hiPSC-BMECs with Pf-iRBC co-culture compared to uninfected RBC co-culture. In addition, there was an increase in expression of angiogenin, platelet factor-4, and phospho-heat shock protein-27 in the Pf-iRBCs co-culture compared to uninfected RBC co-culture. Conclusion: These findings demonstrate the validity of our hiPSC-BMECs based model of the BBB, that displays enhanced barrier integrity and appropriate TJ protein localization. In the hiPSC-BMEC co-culture with Pf-iRBCs, reduced TEER, increased paracellular permeability, changes in TJ protein localization, increase in expression of adhesion molecules, and markers of angiogenesis and cellular stress all point towards a novel model with enhanced barrier properties, suitable for investigating pathogenic mechanisms underlying BBB disruption in CM.Item Acute kidney injury in Ugandan children with severe malaria is associated with long-term behavioral problems(Public Library of Science, 2019-12-17) Hickson, Meredith R.; Conroy, Andrea L.; Bangirana, Paul; Opoka, Robert O.; Idro, Richard; Ssenkusu, John M.; John, Chandy C.; Pediatrics, School of MedicineBackground Acute kidney injury (AKI) is a risk factor for neurocognitive impairment in severe malaria (SM), but the impact of AKI on long-term behavioral outcomes following SM is unknown. Methods We conducted a prospective study on behavioral outcomes of Ugandan children 1.5 to 12 years of age with two forms of severe malaria, cerebral malaria (CM, n = 226) or severe malarial anemia (SMA, n = 214), and healthy community children (CC, n = 173). AKI was defined as a 50% increase in creatinine from estimated baseline. Behavior and executive function were assessed at baseline and 6, 12, and 24 months later using the Child Behavior Checklist and Behavior Rating Inventory of Executive Function, respectively. Age-adjusted z-scores were computed for each domain based on CC scores. The association between AKI and behavioral outcomes was evaluated across all time points using linear mixed effect models, adjusting for sociodemographic variables and disease severity. Results AKI was present in 33.2% of children with CM or SMA at baseline. Children ≥6 years of age with CM or SMA who had AKI on admission had worse scores in socio-emotional function in externalizing behaviors (Beta (95% CI), 0.52 (0.20, 0.85), p = 0.001), global executive function (0.48 (0.15, 0.82), p = 0.005) and behavioral regulation (0.66 (0.32, 1.01), p = 0.0002) than children without AKI. There were no behavioral differences associated with AKI in children <6 years of age. Conclusions AKI is associated with long-term behavioral problems in children ≥6 years of age with CM or SMA, irrespective of age at study enrollment.Item Acute kidney injury, persistent kidney disease, and post-discharge morbidity and mortality in severe malaria in children: A prospective cohort study(Elsevier, 2022-02-12) Namazzi, Ruth; Batte, Anthony; Opoka, Robert O.; Bangirana, Paul; Schwaderer, Andrew L.; Berrens, Zachary; Datta, Dibyadyuti; Goings, Michael; Ssenkusu, John M.; Goldstein, Stuart L.; John, Chandy C.; Conroy, Andrea L.; Pediatrics, School of MedicineBackground: Globally, 85% of acute kidney injury (AKI) cases occur in low-and-middle-income countries. There is limited information on persistent kidney disease (acute kidney disease [AKD]) following severe malaria-associated AKI. Methods: Between March 28, 2014, and April 18, 2017, 598 children with severe malaria and 118 community children were enrolled in a two-site prospective cohort study in Uganda and followed up for 12 months. The Kidney Disease: Improving Global Outcomes (KDIGO) criteria were used to define AKI (primary exposure) and AKD at 1-month follow-up (primary outcome). Plasma neutrophil gelatinase-associated lipocalin (NGAL) was assessed as a structural biomarker of AKI. Findings: The prevalence of AKI was 45·3% with 21·5% of children having unresolved AKI at 24 h. AKI was more common in Eastern Uganda. In-hospital mortality increased across AKI stages from 1·8% in children without AKI to 26·5% with Stage 3 AKI (p < 0·0001). Children with a high-risk plasma NGAL test were more likely to have unresolved AKI (OR, 7·00 95% CI 4·16 to 11·76) and die in hospital (OR, 6·02 95% CI 2·83 to 12·81). AKD prevalence was 15·6% at 1-month follow-up with most AKD occurring in Eastern Uganda. Risk factors for AKD included severe/unresolved AKI, blackwater fever, and a high-risk NGAL test (adjusted p < 0·05). Paracetamol use during hospitalization was associated with reduced AKD (p < 0·0001). Survivors with AKD post-AKI had higher post-discharge mortality (17·5%) compared with children without AKD (3·7%). Interpretation: Children with severe malaria-associated AKI are at risk of AKD and post-discharge mortality.Item Adipose tissue parasite sequestration drives leptin production in mice and correlates with human cerebral malaria(American Association for the Advancement of Science, 2021-03-24) Mejia, Pedro; Treviño-Villarreal, J. Humberto; De Niz, Mariana; Meibalan, Elamaran; Longchamp, Alban; Reynolds, Justin S.; Turnbull, Lindsey B.; Opoka, Robert O.; Roussilhon, Christian; Spielmann, Tobias; Ozaki, C. Keith; Heussler, Volker T.; Seydel, Karl B.; Taylor, Terrie E.; John, Chandy C.; Milner, Danny A.; Marti, Matthias; Mitchell, James R.; Medicine, School of MedicineCirculating levels of the adipokine leptin are linked to neuropathology in experimental cerebral malaria (ECM), but its source and regulation mechanism remain unknown. Here, we show that sequestration of infected red blood cells (iRBCs) in white adipose tissue (WAT) microvasculature increased local vascular permeability and leptin production. Mice infected with parasite strains that fail to sequester in WAT displayed reduced leptin production and protection from ECM. WAT sequestration and leptin induction were lost in CD36KO mice; however, ECM susceptibility revealed sexual dimorphism. Adipocyte leptin was regulated by the mechanistic target of rapamycin complex 1 (mTORC1) and blocked by rapamycin. In humans, although Plasmodium falciparum infection did not increase circulating leptin levels, iRBC sequestration, tissue leptin production, and mTORC1 activity were positively correlated with CM in pediatric postmortem WAT. These data identify WAT sequestration as a trigger for leptin production with potential implications for pathogenesis of malaria infection, prognosis, and treatment.Item Association of Plasma Tau With Mortality and Long-term Neurocognitive Impairment in Survivors of Pediatric Cerebral Malaria and Severe Malarial Anemia(American Medical Association, 2021-12) Datta, Dibyadyuti; Bangirana, Paul; Opoka, Robert O.; Conroy, Andrea L.; Co, Katrina; Bond, Caitlin; Zhao, Yi; Kawata, Keisuke; Saykin, Andrew J.; John, Chandy C.; Biostatistics and Health Data Science, School of MedicineImportance: Cerebral malaria (CM) and severe malarial anemia (SMA) are associated with persistent neurocognitive impairment (NCI) among children in Africa. Identifying blood biomarkers of acute brain injury that are associated with future NCI could allow early interventions to prevent or reduce NCI in survivors of severe malaria. Objective: To investigate whether acutely elevated tau levels are associated with future NCI in children after CM or SMA. Design, setting, and participants: This prospective cohort study was conducted at Mulago National Referral Hospital in Kampala, Uganda, from March 2008 to October 2015. Children aged 1.5 to 12 years with CM (n = 182) or SMA (n = 162) as well as community children (CC; n = 123) were enrolled in the study. Data analysis was conducted from January 2020 to May 2021. Exposure: CM or SMA. Main outcomes and measures: Enrollment plasma tau levels were measured using single-molecule array detection technology. Overall cognition (primary) and attention and memory (secondary) z scores were measured at 1 week and 6, 12, and 24 months after discharge using tools validated in Ugandan children younger than 5 years or 5 years and older. Results: A total of 467 children were enrolled. In the CM group, 75 (41%) were girls, and the mean (SD) age was 4.02 (1.92) years. In the SMA group, 59 (36%) were girls, and the mean (SD) age was 3.45 (1.60) years. In the CC group, 65 (53%) were girls, and the mean (SD) age was 3.94 (1.92) years. Elevated plasma tau levels (>95th percentile in CC group; >6.43 pg/mL) were observed in 100 children (55%) with CM and 69 children (43%) with SMA (P < .001). In children with CM who were younger than 5 years, elevated plasma tau levels were associated with increased mortality (odds ratio [OR], 3.06; 95% CI, 1.01-9.26; P = .048). In children with CM who were younger than 5 years at both CM episode and follow-up neurocognitive testing, plasma tau levels (log10 transformed) were associated with worse overall cognition scores over 24-month follow-up (β = -0.80; 95% CI, -1.32 to -0.27; P = .003). In children with CM who were younger than 5 years at CM episode and 5 years or older at follow-up neurocognitive testing, plasma tau was associated with worse scores in attention (β = -1.08; 95% CI, -1.79 to -0.38; P = .003) and working memory (β = -1.39; 95% CI, -2.18 to -0.60; P = .001). Conclusions and relevance: In this study, plasma tau, a marker of injury to neuronal axons, was elevated in children with CM or SMA and was associated with mortality and persistent NCI in children with CM younger than 5 years.Item Association of severe malaria with cognitive and behavioural outcomes in low- and middle-income countries: a meta-analysis and systematic review(BMC, 2023-08-03) Ssemata, Andrew Sentoogo; Nakitende, Ann Jacquelline; Kizito, Simon; Thomas, Melissa R.; Islam, Sumaiya; Bangirana, Paul; Nakasujja, Noeline; Yang, Ziyi; Yu, Yunpeng; Tran, Tuan M.; John, Chandy C.; McHenry, Megan S.; Social and Behavioral Sciences, School of Public HealthBackground: Malaria affects 24 million children globally, resulting in nearly 500,000 child deaths annually in low- and middle-income countries (LMICs). Recent studies have provided evidence that severe malaria infection results in sustained impairment in cognition and behaviour among young children; however, a formal meta-analysis has not been published. The objective was to assess the association between severe malaria infection with cognitive and behavioural outcomes among children living in LMICs. Methods: Six online bibliographic databases were searched and reviewed in November 2022. Studies included involved children < 18 years of age living in LMICs with active or past severe malaria infection and measured cognitive and/or behaviour outcomes. The quality of studies was assessed. Definitions of severe malaria included cerebral malaria, severe malarial anaemia, and author-defined severe malaria. Results from all studies were qualitatively summarized. For studies with relevant data on attention, learning, memory, language, internalizing behaviour and externalizing behaviour, results were pooled and a meta-analysis was performed. A random-effects model was used across included cohorts, yielding a standardized mean difference between the severe malaria group and control group. Results: Out of 3,803 initial records meeting the search criteria, 24 studies were included in the review, with data from 14 studies eligible for meta-analysis inclusion. Studies across sub-Saharan Africa assessed 11 cohorts of children from pre-school to school age. Of all the studies, composite measures of cognition were the most affected areas of development. Overall, attention, memory, and behavioural problems were domains most commonly found to have lower scores in children with severe malaria. Meta-analysis revealed that children with severe malaria had worse scores compared to children without malaria in attention (standardized mean difference (SMD) -0.68, 95% CI -1.26 to -0.10), memory (SMD -0.52, 95% CI -0.99 to -0.06), and externalizing behavioural problems (SMD 0.45, 95% CI 0.13-0.78). Conclusion: Severe malaria is associated with worse neuropsychological outcomes for children living in LMICs, specifically in attention, memory, and externalizing behaviours. More research is needed to identify the long-term implications of these findings. Further interventions are needed to prevent cognitive and behavioural problems after severe malaria infection.Item Cerebral malaria is associated with long-term mental health disorders: a cross sectional survey of a long-term cohort(Springer (Biomed Central Ltd.), 2016) Idro, Richard; Kakooza-Mwesige, Angelina; Asea, Benjamin; Ssebyala, Keron; Bangirana, Paul; Opoka, Robert O.; Lubowa, Samson K.; Semrud-Clikeman, Margaret; John, Chandy C.; Nalugya, Joyce; Department of Pediatrics, IU School of MedicineBACKGROUND: Cerebral malaria (CM) and severe malarial anaemia (SMA) are associated with neuro-developmental impairment in African children, but long-term mental health disorders in these children are not well defined. METHODS: A cohort of children previously exposed to CM (n = 173) or SMA (n = 99) had neurologic assessments performed and screening for behaviour difficulties using the Strengths and Difficulties Questionnaire (SDQ) a median of 21 months after the disease episode. These findings were compared to concurrently recruited community children (CC, n = 108). Participants with SDQ total difficulties score ≥ 17 had a mental health interview with the child and adolescent version of the Mini-International Neuropsychiatric Interview (MINI-KID) and a sample had brain magnetic resonance imaging (MRI). RESULTS: Fifty-five children had SDQ score ≥ 17. On the MINI-KID, these children were classified as having no difficulties (n = 18), behaviour difficulties only (n = 13) or a mental health disorder (n = 24). Behaviour difficulties were seen in similar frequencies in CM (3.5%), SMA (4.0%) and CC (2.8%). In contrast, mental health disorders were most frequent in CM (10.4%), followed by SMA (4.0%) and CC (1.8%). Externalizing disorders (conduct, oppositional defiance and attention deficit hyperactivity) were the most common mental health disorders. The median total coma duration was 72 (IQR 36.0-115.0) h in patients with mental health disorders compared to 48 (IQR 28.5-78.7) h in those without, p = 0.039. Independent risk factors for mental health disorder included neurologic deficit at discharge (OR 4.09 (95% CI 1.60, 10.5) and seizure recurrences during hospitalization, (OR 2.80, 95% CI 1.13, 6.97). Brain MRI findings consistent with small vessel ischaemic neural injury was seen in over half of these children. CONCLUSIONS: Cerebral malaria may predispose children to mental health disorders, possibly as a consequence of ischaemic neural injury. There is urgent need for programmes of follow-up, diagnosis and interventions for these children.Item Cerebrospinal fluid biomarkers provide evidence for kidney-brain axis involvement in cerebral malaria pathogenesis(Frontiers Media, 2023-05-02) Conroy, Andrea L.; Datta, Dibyadyuti; Opoka, Robert O.; Batte, Anthony; Bangirana, Paul; Gopinadhan, Adnan; Mellencamp, Kagan A.; Akcan-Arikan, Ayse; Idro, Richard; John, Chandy C.; Pediatrics, School of MedicineIntroduction: Cerebral malaria is one of the most severe manifestations of malaria and is a leading cause of acquired neurodisability in African children. Recent studies suggest acute kidney injury (AKI) is a risk factor for brain injury in cerebral malaria. The present study evaluates potential mechanisms of brain injury in cerebral malaria by evaluating changes in cerebrospinal fluid measures of brain injury with respect to severe malaria complications. Specifically, we attempt to delineate mechanisms of injury focusing on blood-brain-barrier integrity and acute metabolic changes that may underlie kidney-brain crosstalk in severe malaria. Methods: We evaluated 30 cerebrospinal fluid (CSF) markers of inflammation, oxidative stress, and brain injury in 168 Ugandan children aged 18 months to 12 years hospitalized with cerebral malaria. Eligible children were infected with Plasmodium falciparum and had unexplained coma. Acute kidney injury (AKI) on admission was defined using the Kidney Disease: Improving Global Outcomes criteria. We further evaluated blood-brain-barrier integrity and malaria retinopathy, and electrolyte and metabolic complications in serum. Results: The mean age of children was 3.8 years (SD, 1.9) and 40.5% were female. The prevalence of AKI was 46.3% and multi-organ dysfunction was common with 76.2% of children having at least one organ system affected in addition to coma. AKI and elevated blood urea nitrogen, but not other measures of disease severity (severe coma, seizures, jaundice, acidosis), were associated with increases in CSF markers of impaired blood-brain-barrier function, neuronal injury (neuron-specific enolase, tau), excitatory neurotransmission (kynurenine), as well as altered nitric oxide bioavailability and oxidative stress (p < 0.05 after adjustment for multiple testing). Further evaluation of potential mechanisms suggested that AKI may mediate or be associated with CSF changes through blood-brain-barrier disruption (p = 0.0014), ischemic injury seen by indirect ophthalmoscopy (p < 0.05), altered osmolality (p = 0.0006) and through alterations in the amino acids transported into the brain. Conclusion: In children with cerebral malaria, there is evidence of kidney-brain injury with multiple potential pathways identified. These changes were specific to the kidney and not observed in the context of other clinical complications.Item Delayed iron improves iron status without altering malaria risk in severe malarial anemia(Oxford University Press, 2020-05) Cusick, Sarah E.; Opoka, Robert O.; Ssemata, Andrew S.; Georgieff, Michael K.; John, Chandy C.; Pediatrics, School of MedicineBackground: WHO guidelines recommend concurrent iron and antimalarial treatment in children with malaria and iron deficiency, but iron may not be well absorbed or utilized during a malaria episode. Objectives: We aimed to determine whether starting iron 28 d after antimalarial treatment in children with severe malaria and iron deficiency would improve iron status and lower malaria risk. Methods: We conducted a randomized clinical trial on the effect of immediate compared with delayed iron treatment in Ugandan children 18 mo-5 y of age with 2 forms of severe malaria: cerebral malaria (CM; n = 79) or severe malarial anemia (SMA; n = 77). Asymptomatic community children (CC; n = 83) were enrolled as a comparison group. Children with iron deficiency, defined as zinc protoporphyrin (ZPP) ≥ 80 µmol/mol heme, were randomly assigned to receive a 3-mo course of daily oral ferrous sulfate (2 mg · kg-1 · d-1) either concurrently with antimalarial treatment (immediate arm) or 28 d after receiving antimalarial treatment (delayed arm). Children were followed for 12 mo. Results: All children with CM or SMA, and 35 (42.2%) CC, were iron-deficient and were randomly assigned to immediate or delayed iron treatment. Immediate compared with delayed iron had no effect in any of the 3 study groups on the primary study outcomes (hemoglobin concentration and prevalence of ZPP ≥ 80 µmol/mol heme at 6 mo, malaria incidence over 12 mo). However, after 12 mo, children with SMA in the delayed compared with the immediate arm had a lower prevalence of iron deficiency defined by ZPP (29.4% compared with 65.6%, P = 0.006), a lower mean concentration of soluble transferrin receptor (6.1 compared with 7.8 mg/L, P = 0.03), and showed a trend toward fewer episodes of severe malaria (incidence rate ratio: 0.39; 95% CI: 0.14, 1.12). Conclusions: In children with SMA, delayed iron treatment did not increase hemoglobin concentration, but did improve long-term iron status over 12 mo without affecting malaria incidence.This trial was registered at clinicaltrials.gov as NCT01093989.Item Elevated Plasma Soluble ST2 Levels are Associated With Neuronal Injury and Neurocognitive Impairment in Children With Cerebral Malaria(Case Western Reserve University, 2022-06-23) Fernander, Elizabeth M.; Adogamhe, Pontian; Datta, Dibyadyuti; Bond, Caitlin; Zhao, Yi; Bangirana, Paul; Conroy, Andrea L.; Opoka, Robert O.; John, Chandy C.; Pediatrics, School of MedicineBackground: Murine experimental cerebral malaria studies suggest both protective and deleterious central nervous system effects from alterations in the interleukin-33 (IL-33)/ST2 pathway. Methods: We assessed whether soluble ST2 (sST2) was associated with neuronal injury or cognitive impairment in a cohort of Ugandan children with cerebral malaria (CM, n=224) or severe malarial anemia (SMA, n=193). Results: Plasma concentrations of sST2 were higher in children with CM than in children with SMA or in asymptomatic community children. Cerebrospinal fluid (CSF) sST2 levels were elevated in children with CM compared with North American children. Elevated plasma and CSF ST2 levels in children with CM correlated with increased endothelial activation and increased plasma and CSF levels of tau, a marker of neuronal injury. In children with CM who were ≥5 years of age at the time of their malaria episode, but not in children <5 years of age, elevated risk factor-adjusted plasma levels of sST2 were associated with worse scores for overall cognitive ability and attention over a 2-year follow-up. Conclusions: The study findings suggest that sST2 may contribute to neuronal injury and long-term neurocognitive impairment in older children with CM.