Plasma angiopoietin-2 is associated with age-related deficits in cognitive sub-scales in Ugandan children following severe malaria

Apolipoprotein-E4: risk of severe malaria and mortality and cognitive impairment in pediatric cerebral malaria

BACKGROUND

The relationship of apolipoprotein-E4 (APOE4) to mortality and cognition after severe malaria in children is unknown.

METHODS

APOE genotyping was performed in children with cerebral malaria (CM, n = 261), severe malarial anemia (SMA, n = 224) and community children (CC, n = 213). Cognition was assessed over 2-year follow-up.

RESULTS

A greater proportion of children with CM or SMA than CC had APOE4 (n = 162, 31.0%; n = 142, 31.7%; n = 103, 24.2%, respectively, p = 0.02), but no difference was seen in APOE3 (n = 310, 59.4%; n = 267, 59.6%; n = 282, 66.2%, respectively, p = 0.06), or APOE2 (n = 50, 9.6%; n = 39, 8.7%; and n = 41, 9.6%, respectively, p = 0.87). APOE4 was associated with increased mortality in CM (odds ratio, 2.28; 95% CI, 1.01, 5.11). However, APOE4 was associated with better long-term cognition (ß, 0.55; 95% CI, 0.04, 1.07, p = 0.04) and attention (ß 0.78; 95% CI, 0.26, 1.30, p = 0.004) in children with CM < 5 years old, but worse attention (ß, -0.90; 95% CI, -1.69, -0.10, p = 0.03) in children with CM ≥ 5 years old. Among children with CM, risk of post-discharge malaria was increased with APOE4 and decreased with APOE3.

CONCLUSIONS

APOE4 is associated with higher risk of CM or SMA and mortality in children with CM, but better long-term cognition in CM survivors <5 years of age.

Interplay Between the Immune and Nervous Cognitive Systems in Homeostasis and in Malaria

The immune and nervous systems can be thought of as cognitive and plastic systems, since they are both involved in cognition/recognition processes and can be architecturally and functionally modified by experience, and such changes can influence each other's functioning. The immune system can affect nervous system function depending on the nature of the immune stimuli and the pro/anti-inflammatory responses they generate. Here we consider interactions between the immune and nervous systems in homeostasis and disease, including the beneficial and deleterious effects of immune stimuli on brain function and the impact of severe and non-severe malaria parasite infections on neurocognitive and behavioral parameters in human and experimental murine malaria. We also discuss the effect of immunization on the reversal of cognitive deficits associated with experimental non-severe malaria in a model susceptible to the development of the cerebral form of the illness. Finally, we consider the possibility of using human vaccines, largely exploited as immune-prophylactics for infectious diseases, as therapeutic tools to prevent or mitigate the expression of cognitive deficits in infectious and chronic degenerative diseases.

Elevated brain derived neurotrophic factor in plasma and interleukin-6 levels in cerebrospinal fluid in meningitis compared to cerebral malaria

Neurological infections, such as Cerebral malaria (CM) and meningitis are associated with high mortality and in survivors, particularly young children, persistent neurologic deficits often remain. As brain inflammation plays a role in the development of these neurological sequelae, multiplex assays were used to assess a select set of immune mediators in both plasma and cerebrospinal fluid (CSF) from Zambian children with neurological infections. Both CM and meningitis patients showed high levels of markers for vascular inflammation, such as soluble ICAM-1 and angiopoietins. Although high levels of angiopoietin 1 and angiopoietin 2 were found in the meningitis group, their levels in the CSF were low and did not differ. As expected, there were high levels of cytokines and notably a significantly elevated IL-6 level in the CSF of the meningitis group. Interestingly, although elevated levels BDNF were found, BDNF levels were significantly higher in plasma of the meningitis group but similar in the CSF. The striking differences in plasma BDNF and IL-6 levels in the CSF point to markedly different neuro-pathological processes. Therefore, further investigations in the role of both IL-6 and BDNF in the neurological outcomes are needed.

Cerebrospinal fluid biomarkers provide evidence for kidney-brain axis involvement in cerebral malaria pathogenesis

Introduction

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.

The kidney-brain pathogenic axis in severe falciparum malaria

Severe falciparum malaria is a medical emergency and a leading cause of death and neurodisability in endemic areas. Common complications include acute kidney injury (AKI) and cerebral malaria, and recent studies have suggested links between kidney and brain dysfunction in Plasmodium falciparum infection. Here, we review these new findings and present the hypothesis of a pivotal pathogenic crosstalk between the kidneys and the brain in severe falciparum malaria. We highlight the evidence of a role for distant organ involvement in the development of cerebral malaria and subsequent neurocognitive impairment post-recovery, describe the challenges associated with current diagnostic shortcomings for both AKI and brain involvement in severe falciparum malaria, and explore novel potential therapeutic strategies.

Pathophysiology of Acute Kidney Injury in Malaria and Non-Malarial Febrile Illness: A Prospective Cohort Study

Acute kidney injury (AKI) is a life-threatening complication. Malaria and sepsis are leading causes of AKI in low-and-middle-income countries, but its etiology and pathogenesis are poorly understood. A prospective observational cohort study was conducted to evaluate pathways of immune and endothelial activation in children hospitalized with an acute febrile illness in Uganda. The relationship between clinical outcome and AKI, defined using the Kidney Disease: Improving Global Outcomes criteria, was investigated. The study included 967 participants (mean age 1.67 years, 44.7% female) with 687 (71.0%) positive for malaria by rapid diagnostic test and 280 (29.1%) children had a non-malarial febrile illness (NMFI). The frequency of AKI was higher in children with NMFI compared to malaria (AKI, 55.0% vs. 46.7%, p = 0.02). However, the frequency of severe AKI (stage 2 or 3 AKI) was comparable (12.1% vs. 10.5%, p = 0.45). Circulating markers of both immune and endothelial activation were associated with severe AKI. Children who had malaria and AKI had increased mortality (no AKI, 0.8% vs. AKI, 4.1%, p = 0.005), while there was no difference in mortality among children with NMFI (no AKI, 4.0% vs. AKI, 4.6%, p = 0.81). AKI is a common complication in children hospitalized with acute infections. Immune and endothelial activation appear to play central roles in the pathogenesis of AKI.

Malaria Related Neurocognitive Deficits and Behavioral Alterations

Typical of tropical and subtropical regions, malaria is caused by protozoa of the genus Plasmodium and is, still today, despite all efforts and advances in controlling the disease, a major issue of public health. Its clinical course can present either as the classic episodes of fever, sweating, chills and headache or as nonspecific symptoms of acute febrile syndromes and may evolve to severe forms. Survivors of cerebral malaria, the most severe and lethal complication of the disease, might develop neurological, cognitive and behavioral sequelae. This overview discusses the neurocognitive deficits and behavioral alterations resulting from human naturally acquired infections and murine experimental models of malaria. We highlighted recent reports of cognitive and behavioral sequelae of non-severe malaria, the most prevalent clinical form of the disease worldwide. These sequelae have gained more attention in recent years and therapies for them are required and demand advances in the understanding of neuropathogenesis. Recent studies using experimental murine models point to immunomodulation as a potential approach to prevent or revert neurocognitive sequelae of malaria.

Sequential dysregulated plasma levels of angiopoietins (ANG-2 and ratios of ANG-2/ANG-1) are associated with malaria severity and mortality among hospital admitted cases in South Bastar Region of Chhattisgarh, Central India

Cerebral malaria (CM) is one of the most severe forms of P. falciparum infection, with an associated high case-fatality rate. Angiopoietins (ANG-1 and ANG-2) are important biomarkers of endothelial activation and dysfunction. This study was carried out in Maharani Hospital and associated Medical College, Jagdalpur, CG, Central India from 2010 to 2014. Based on the treatment recovery patterns, cases (n = 65) were classified as mild malaria with rapid recovery (MM-RR), n= 14; non-cerebral severe malaria with moderately fast recovery (NCSM-MFR), n= 9; CM survivors with slow recovery (CMS-SR), n= 36 and deteriorated CM non-survivors (Det-CMNS), n= 6. Plasma levels (pg/ml) of ANG-1 and ANG-2 were measured by ELISA in all the samples at the time of hospital admission and 48 hours of treatment. Levels were also measured in available samples at the third time point (time of discharge for survivors or 72 hours post-treatment in fatal cases). Data analysis was done by appropriate statistical tests using Stata 11.0 and SPSS 25.0 software. At the time of admission, ANG-2 and ratios of ANG-2/ANG-1 significantly distinguished Det-CMNS cases from MM-RR and NCSM-MFR cases with good AUC scores (0.8-0.9). Further, Det-CMNS cases could also be distinguished from MM-RR, NCSM-MFR, and CMS-SR cases by ANG-2 (AUC scores 0.9) and ratios of ANG-2/ANG-1 (AUC: 0.8-0.9) at 48 hours of treatment. Paired analysis of sequential measurement of angiopoietins revealed that compared to admission levels, the ratios of ANG-2/ANG-1 significantly declined 48 hours after treatment in MM-RR (p= 0.041), NCSM-MFR (p= 0.050), and CMS-SR (p= 0.0002) cases but not in cases of Det-CMNS (p= 0.916). In conclusion, plasma levels of ANG-2 and ratios of ANG-2/ANG-1 may serve as good biomarkers to distinguish the malaria severity at the time of hospital admission and recovery patterns upon treatment in Central India.