Oxidative stress in children with severe malaria

The roles of vitamin C in infectious diseases: A comprehensive review

Vitamin C is a versatile nutrient with essential antioxidant properties and roles in amino acid metabolism, collagen promotion, and hormone synthesis. It has long been regarded as benefitting infectious disease management, although its specific roles remain uncertain. The dominant view is that this efficacy not only stems from its redox regulation in the body but also from its profound impact on the immune system. This review provides a comprehensive overview of Vitamin C's effects on redox regulation and shows how the vitamin influences various immune cells and cell-intrinsic innate immunity signaling pathways, thereby updating and expanding our previous perspectives. Clinically, though some studies and case series have suggested potential benefits of Vitamin C in preventing and (or) treating respiratory tract infections and sepsis and septic shock, the evidence remains controversial. The current data is insufficient to support the routine clinical use of Vitamin C in managing these diseases and requires further rigorous evaluation to establish definitive efficacy and safety profiles. This review thoroughly examines current clinical research progress on Vitamin C, summarizes the primary controversies and their underlying causes, and proposes directions for future clinical research. Furthermore, preclinical evidence shows potential roles for Vitamin C in the supplementary treatment of the "Big Three" infectious diseases: acquired immunodeficiency syndrome (AIDS), tuberculosis, and malaria; however, systematic clinical studies in these areas are lacking. We examine related in vitro and animal studies, as well as clinical trials, and discuss potential roles for Vitamin C as a treatment and (or) adjuvant therapy.

Testosterone Modulates Oxidative Stress in a Sexually Dimorphic Manner in CBA/Ca Mice Infected with Plasmodium berghei ANKA

Malaria, the deadliest parasitic disease in the world, is sexually dimorphic, inflammatory, and oxidative. Males experience more severe symptoms and mortality than females do; therefore, the roles of 17β-estradiol and testosterone in this phenomenon have been studied. Both hormones affect oxidative stress, the primary mechanism of Plasmodium elimination. Estradiol has antioxidant activity, but the role of testosterone is controversial. Testosterone increases oxidative stress by reducing superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities, which increase lipoperoxidation in the testis. However, the antioxidant properties of testosterone in prostate and nervous tissue have also been reported. The discrepancies are probably because when testosterone levels increase, the aromatase enzyme transforms testosterone into estrogens that possess antioxidant activity, which masks the results. Therefore, it is unknown whether testosterone is involved in the sexual dimorphism that occurs in oxidative stress in malaria. In this work, we administered testosterone and simultaneously inhibited aromatase with letrozole to evaluate the role of testosterone in the sexually dimorphic pattern of oxidative stress that occurs in the blood, spleen, and brain of male and female CBA/Ca mice infected with Plasmodium berghei ANKA (P. berghei ANKA). Testosterone triggers parasitemia in males, who also display more oxidative stress than females in the absence of infection, leading to sexually dimorphic patterns. Interestingly, increasing testosterone levels in infected mice reduced oxidative stress in males and increased oxidative stress in females, reversing or eliminating the dimorphic patterns observed. Oxidative stress varies in each tissue; the brain was the most protected, while the blood was the greatest damaged. Our findings highlight the role of testosterone as a regulator of oxidative stress in a tissue and sex-specific manner; therefore, understanding the role of testosterone in malaria may contribute to the development of sex-specific personalized antimalarial therapies.

Clinical, immune and genetic risk factors of malaria-associated acute kidney injury in Zambian children: A study protocol

BACKGROUND

Acute kidney injury (AKI) affects nearly half of children with severe malaria and increases the risk of adverse outcomes such as death and poor cognitive function. The pathogenesis and predictors of malaria-associated acute kidney injury (MAKI) are not fully described. This study aims to determine the clinical, immune, and genetic correlates of risk to AKI in Zambian children admitted with malaria. In addition, we intend to assess a modified renal angina index (mRAI), kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and soluble urokinase receptor (suPAR), when done on the first day of admission, for the ability to predict AKI two days later (day 3) in children admitted with malaria.

METHODS

This is an unmatched case-control study with a nested prospective observational study. A case-to-control ratio of 1:1 is used and 380 children with malaria and aged less than 16 years are being recruited from two hospitals in Zambia. Eligible children are recruited after obtaining written informed consent. Recruitment occurs during the malaria season and began on 6th March 2024 and will continue until July 2025. AKI is defined using the 2012 KIDGO AKI creatinine criteria, and cases are defined as children admitted with malaria who develop AKI within 72 hours of admission, while controls are children admitted with malaria but with no AKI. Serum creatinine is collected on Day 1 within 24 hours of admission, on Day 3 and then again on discharge or day 7, whichever comes sooner. Baseline biomarker concentrations will be determined using the Luminex multiplex Elisa system or high-sensitivity ELISA. SPSS version 29 will be used for data analysis. Descriptive statistics and inferential statistical tests will be run as appropriate. A p ≤ 0.05 will be considered as significant. The sensitivity, specificity, and estimates of the area under the curve (AUC) for the renal angina score will be determined.

Oxidative Stress in Children and Adolescents: Insights Into Human Biology

Oxidative stress (OS) is a key biological challenge and selective pressure for organisms with aerobic metabolism. The result of the imbalance between reactive oxygen species production and antioxidant defense, OS can damage proteins, lipids, and nucleic acids and plays an important role in driving variation in biological aging and health. Among humans, OS research has focused overwhelmingly on adults, with demonstrated connections between OS, inflammation, and metabolic and neurodegenerative conditions. Relatively little attention has been given to OS during childhood and adolescence. This lack of early life OS research exists despite clear implications for informing human life history evolution, subadult development, and lifelong health. Here, we review current knowledge on OS during human subadulthood. Our objectives are threefold: (1) To highlight common methods for measuring OS among children and adolescents and to establish typical measurement values; (2) To summarize the evidence linking demographic and ecological factors to variation in subadult OS; (3) To identify avenues for future OS research in human biology. Our review underscores an expanding methodological toolkit for assessing OS among children and adolescents. Subadult OS is considerably elevated compared to OS among adults, a pattern eliciting unknown consequences and likely related to increased early life metabolic demands (e.g., unique human brain development). Factors such as diet, physical activity, infectious disease, and structural neglect also appear to drive subadult OS. Current limitations for research on subadult OS are evident. Future work should emphasize evolutionary, biocultural, and energetic life course perspectives to advance this promising area of human biology.

Assessing the Oxidative Stress Reducing Potential of Spilanthes filicaulis (Schumach & Thonn) Ethyl-Acetate Sub-fractions on Plasmodium berghei Infected Female Mice

PURPOSE

Infections by Plasmodium parasite actuate oxidative stress. As malaria parasite actions overwhelm host antioxidant defense by producing excessive reactive species during haemoglobin degradation. This study aimed to evaluate the oxidative status by considering the antioxidant level of ethyl-acetate sub-fractions of Spilanthes filicaulis (ESSF) extract on Plasmodium berghei NK-65 parasitized mice.

METHODS

Sixty female mice weighing 20.0 ± 3.0 g were inoculated intraperitoneally with 0.2 mL of parasitized erythrocytes randomly selected into five groups of 12 mice, Groups I and II were orally administered with normal saline (10 mL/kg) and chloroquine (10 mg/kg) while, Groups III, IV and V were administered 250,500 and 750 mg/kg per day respectively of ESSF. Mice in each group were sacrificed on days 4 and 8 post treatment, thereafter blood and liver samples were collected and prepared using standard methods to obtain erythrocytes and liver homogenates. Malondialdehyde (MDA), a measure of lipid peroxidation, superoxide dismutase (SOD) and catalase (CAT) level was assessed in the erythrocyte and liver.

RESULTS

Administration of ESSF produced a significant (p < 0.05) decrease in the MDA concentration of the parasitized treated group when compared to parasitized untreated group on day 4. Concomitantly, a significant (p < 0.05) increase in SOD and CAT activity in the treated groups with a corresponding decrease in the untreated group on day 4. However, effects of this action were more pronounced on day 8 in both tissues.

CONCLUSION

These findings suggest that ESSF might contribute to the protection of malaria infected mice against oxidative disruptions by improving antioxidant status.

Alteration of ceruloplasmin in patients with malaria: a systematic review and meta-analysis of observational studies

BACKGROUND

The evidences of oxidative stress-related Plasmodium infection may alter the ceruloplasmin levels were inconsistent. This systematic review and meta-analysis aimed to collate and synthesize literatures on malaria and ceruloplasmin concentrations.

METHODS

The systematic review has been registered with PROSPERO (CRD42023454859). Six electronic databases were systematically searched for investigated ceruloplasmin levels in malaria: ProQuest, EMBASE, MEDLINE, Ovid, PubMed, and Scopus, from their inception to August 2023. The quality of the included studies was assessed using the Joanna Briggs Institute (JBI) critical appraisal tools for cross-sectional, cohort, and case-control studies. Qualitative synthesis was undertaken to summarize findings from the included studies. For quantitative synthesis, a meta-analysis was performed using random-effects models.

RESULTS

A total of 411 articles were retrieved, and nine studies were included in the review. The majority of included studies found significantly increased ceruloplasmin levels in malaria patients compared to uninfected controls. The meta-analysis showed a significant increase of ceruloplasmin in patients with malaria as compared to uninfected controls (P < 0.01, Hedge's g 1.18, 95% CI 0.90-1.47, I2 59.19%, eight studies).

CONCLUSION

The systematic review and meta-analysis consistently revealed a significant rise in ceruloplasmin levels among malaria patients. Further research is essential to understand the variations in ceruloplasmin levels between different Plasmodium species and the severity of malaria in patients.

Host-parasite interaction in severe and uncomplicated malaria infection in ghanaian children

PURPOSE

During malarial infection, both parasites and host red blood cells (RBCs) come under severe oxidative stress due to the production of free radicals. The host system responds in protecting the RBCs against the oxidative damage caused by these free radicals by producing antioxidants. In this study, we investigated the antioxidant enzyme; superoxide dismutase (SOD) activity and cytokine interactions with parasitaemia in Ghanaian children with severe and uncomplicated malaria.

METHODOLOGY

One hundred and fifty participants aged 0-12 years were administered with structured questionnaires. Active case finding approach was used in participating hospitals to identify and interview cases before treatment was applied. Blood samples were taken from each participant and used to quantify malaria parasitaemia, measure haematological parameters and SOD activity. Cytokine levels were measured by commercial ELISA kits. DNA comet assay was used to evaluate the extent of parasite DNA damage due to oxidative stress.

RESULTS

Seventy - Nine (79) and Twenty- Six (26) participants who were positive with malaria parasites were categorized as severe (56.75 × 103 ± 57.69 parasites/µl) and uncomplicated malaria (5.87 × 103 ± 2.87 parasites/µl) respectively, showing significant difference in parasitaemia (p < 0.0001). Significant negative correlation was found between parasitaemia and SOD activity levels among severe malaria study participants (p = 0.0428). Difference in cytokine levels (IL-10) amongst the control, uncomplicated and severe malaria groups was significant (p < 0.0001). The IFN-γ/IL-10 /TNF-α/IL-10 ratio differed significantly between the malaria infected and non- malaria infected study participants. DNA comet assay revealed damage to Plasmodium parasite DNA.

CONCLUSION

Critical roles played by SOD activity and cytokines as anti-parasitic defense during P. falciparum malaria infection in children were established.

Genotype-environment associations reveal genes potentially linked to avian malaria infection in populations of an endemic island bird

Patterns of pathogen prevalence are, at least partially, the result of coevolutionary host-pathogen interactions. Thus, exploring the distribution of host genetic variation in relation to infection by a pathogen within and across populations can provide important insights into mechanisms of host defence and adaptation. Here, we use a landscape genomics approach (Bayenv) in conjunction with genome-wide data (ddRADseq) to test for associations between avian malaria (Plasmodium) prevalence and host genetic variation across 13 populations of the island endemic Berthelot's pipit (Anthus berthelotii). Considerable and consistent spatial heterogeneity in malaria prevalence was observed among populations over a period of 15 years. The prevalence of malaria infection was also strongly positively correlated with pox (Avipoxvirus) prevalence. Multiple host loci showed significant associations with malaria prevalence after controlling for genome-wide neutral genetic structure. These sites were located near to or within genes linked to metabolism, stress response, transcriptional regulation, complement activity and the inflammatory response, many previously implicated in vertebrate responses to malarial infection. Our findings identify diverse genes - not just limited to the immune system - that may be involved in host protection against malaria and suggest that spatially variable pathogen pressure may be an important evolutionary driver of genetic divergence among wild animal populations, such as Berthelot's pipit. Furthermore, our data indicate that spatio-temporal variation in multiple different pathogens (e.g. malaria and pox in this case) may have to be studied together to develop a more holistic understanding of host pathogen-mediated evolution.

Malaria Is Associated with Diminished Levels of Ascorbic Acid: A Systematic Review and Meta-Analysis

Background: It is still unclear how ascorbic acid levels relate to the pathogenesis of malaria. This systematic review synthesized different ascorbic acid levels in malaria patients with different severity levels of malaria and Plasmodium species. Methods: The systematic review protocol was registered in the PROSPERO database (CRD42023394849). A systematic search of PubMed, Embase, MEDLINE, Ovid, Scopus, and Google Scholar was conducted to identify studies that reported ascorbic acid and malaria. The pooled standardized mean difference (Cohen's d) with 95% confidence intervals (CIs) was calculated using the random-effects model. Results: A total of 1480 articles were obtained from the searches of the databases, and 30 studies were included for syntheses. The meta-analysis revealed that patients with malaria had lower levels of ascorbic acid than those without malaria or uninfected controls (p < 0.01, Cohen's d = -3.71, 95% CI = -4.44 to -2.98, I2 = 98.87%, 30 studies). Comparable levels of ascorbic acid were observed between patients with severe malaria and those with nonsevere malaria (p = 0.06, Cohen's d = -1.39, 95% CI = -2.85 to 0.07, I2 = 96.58%, 4 studies). Similarly, levels of ascorbic acid were comparable between patients with Plasmodium falciparum and Plasmodium vivax malaria (p = 0.34, Cohen's d = -1.06, 95% CI = -3.23 to 1.12, I2 = 97.30%, 3 studies). Conclusions: The meta-analysis reveals diminished levels of ascorbic acid in malaria cases. Manipulating the host's nutritional status, such as by supplementing it with ascorbic acid to restore reactive oxygen species balance, may alter the progression of malarial infection and prevention of disease severity. Antioxid. Redox Signal. 40, 460-469.

Status of Blood Levels of Superoxide Dismutase in Patients with Malaria: A Systematic Review and Meta-Analysis

Aims: The evidence of superoxide dismutase (SOD) in the pathogenesis of malaria is inconsistent. This study aimed to synthesize the evidence of blood levels of SOD in patients with malaria and determine the association of blood levels of SOD with the severity of malaria. Results: A total of 1874 articles were retrieved from database searches and 28 studies were included in the review. The blood levels of SOD were lower in individuals with malaria compared with those without malaria infection (p < 0.01, Cohen's d: -2.06, 95% CI: -2.99 to -1.14), I2: 98.96%, 2181 malaria cases/1186 uninfected cases). There were no differences in blood levels of SOD between severe and nonsevere malaria patients (p = 0.09, Cohen's d: -1.57, 95% CI: -3.39 to 0.26), I2: 96.02%, 69 severe malaria cases/256 nonsevere malaria cases). Innovation and Conclusion: The blood levels of SOD were lower in malaria patients compared with those without malaria infection. Further studies will be required to determine the extent to which SOD might prevent Plasmodium infections during pregnancy. Antioxid. Redox Signal. 40, 222-235.

A Systematic Review and Meta-Analysis Exploring Variations in Copper Levels between Individuals with Malaria and Uninfected Controls

Micronutrient insufficiency has been implicated in malaria pathogenesis. However, the role of copper in malaria remains inconclusive. This study aimed to investigate the association between copper levels and malaria pathogenesis, providing a deeper understanding of copper's role in the disease. A systematic review was conducted following the registered protocol in PROSPERO (CRD42023439732). Multiple databases, including Embase, MEDLINE, Ovid, PubMed, Scopus, and Google Scholar, were searched for relevant studies reporting blood copper levels in patients with malaria. The Joanna Briggs Institute critical appraisal checklist was used for assessing methodological quality. Qualitative and quantitative syntheses were employed, organizing, and summarizing the findings of the included studies. To calculate the standardized mean difference (Hedge's g) and 95% confidence intervals (CIs), a random-effects model was used. After screening the databases, 16 studies were included. Most studies (52.9%) reported that individuals with malaria had significantly higher copper levels than uninfected controls. The meta-analysis, based on 16 studies, showed no significant difference in copper levels between patients with malaria and uninfected controls overall (p = 0.39; Hedges' g, 0.38; 95% CI, -0.48 to 1.25; I2, 98.73%). Subgroup analysis showed a significant difference in copper levels between patients with malaria and uninfected controls among studies conducted in Asia (p < 0.01; Hedges' g, 1.74; 95% CI, 1.04 to 2.44; I2, 90.88%; five studies) and studies employing plasma blood samples (p < 0.01; Hedges' g, 1.13; 95% CI, 0.60 to 2.07; I2, 93.11%; four studies). The qualitative synthesis of the reviewed studies suggests a complex relationship between copper levels and malaria. The meta-analysis results showed no significant difference in copper levels between patients with malaria and uninfected controls overall. However, subgroup analyses based on various factors, including continent and blood sample type, showed copper level variations. These findings highlight the need for further research to better understand the role of copper in malaria pathogenesis by considering geographical factors and the blood sample type used for copper level measurement.

The Association between Malaria and β-Carotene Levels: A Systematic Review and Meta-Analysis

BACKGROUND

β-Carotene, which is a prominent carotenoid with notable antioxidant properties, may play a role in countering the oxidative stresses induced by malaria. The association between β-carotene levels and malaria is not yet fully understood, prompting this systematic review and meta-analysis.

METHODS

A rigorous search of databases, including Nursing and Allied Health Premium, EMBASE, MEDLINE, Ovid, PubMed, Scopus, and Google Scholar, was undertaken to collate studies that focused on β-carotene levels in malaria patients. The selected studies underwent critical appraisal, followed by data extraction for a meta-analysis.

RESULTS

Of the 2498 records initially identified, 10 were deemed suitable for synthesis. A considerable number of these studies indicated a pronounced reduction in β-carotene levels among malaria patients in contrast with uninfected individuals. The meta-analysis, encompassing 421 malaria patients and 240 uninfected controls, revealed a significant correlation between reduced β-carotene levels and malaria (p < 0.01, Hedges's g: -1.26, 95% CI: -2.00-(-0.53), I2: 93.86%, seven studies).

CONCLUSIONS

The conducted systematic review and meta-analysis corroborated the correlation between lower β-carotene levels and malaria. The intricate relationship between malaria and β-carotene merits deeper exploration. A comprehensive understanding of this association might pave the way for innovative therapeutic approaches leveraging the antioxidant attributes of β-carotene to combat malaria-induced oxidative stress.

Impact of malaria on glutathione peroxidase levels: a systematic review and meta-analysis

The primary antioxidant, glutathione peroxidase (GPx), is hypothesized to contribute to the pathophysiology of malaria. This current study conducted a meta-analysis to examine variations in GPx blood levels in malaria patients. Seven electronic databases-ProQuest, Scopus, Embase, MEDLINE, PubMed, Ovid, and Google Scholar-were searched for relevant studies with no limitations to publication language or publication date. The Joanna Briggs Institute critical appraisal tools were used to appraise the risk of bias among the included studies critically. The meta-analysis was conducted by pooling the effect estimates and Hedges's g using a random-effects model. Search results returned 1253 articles, of which 16 studies were used for syntheses. Results of the meta-analysis indicated that malaria patients had decreased blood levels of GPx compared to uninfected individuals (P < 0.01, Hedges' g: - 4.06, 95% CI - 5.49-(- 2.63), I2: 99.07%, 1278 malaria patients/627 uninfected individuals, 15 studies). Subgroup analyses indicated that peripheral levels of GPx were significantly diminished in patients with P. falciparum malaria compared to uninfected controls (P < 0.01, Hedges' g: - 3.06, 95% CI - 4.46-(- 1.65), I2: 98.39%, 9 studies) but not in patients with P. vivax malaria (P = 0.15, Hedges' g: - 2.05, 95% CI - 4.83-0.74), I2: 98.64%, 2 studies) Overall, malaria is associated with declined levels of GPx, particularly in patients with P. falciparum malaria. The finding provides valuable insights that prompt the need to investigate the role of GPx depletion in malaria pathogenesis.

Effect of Malaria on Blood Levels of Vitamin E: A Systematic Review and Meta-Analysis

Vitamin E has an antioxidant property and is associated with protection against malaria. The current study used systematic review and meta-analysis approaches examining the variance in blood levels of vitamin E in malaria patients as compared with uninfected individuals. The protocol for the systematic review was registered with PROSPERO (CRD4202341481). Searches for pertinent studies were carried out on Embase, MEDLINE, Ovid, PubMed, Scopus, ProQuest, and Google Scholar. The combined effect estimate (Cohen's d) of the difference in vitamin E levels in malaria patients as compared with uninfected individuals was estimated using the random effects model. The searches yielded 2009 records, and 23 studies were included in the systematic review. The majority of the studies (80%) found that vitamin E levels were significantly lower in malaria patients than those who were not infected. Overall, the results revealed a significant reduction in blood levels of vitamin E in malaria patients when compared with uninfected individuals (p < 0.01, Cohen's d: -2.74, 95% CI: -3.72-(-1.76), I2: 98.69%, 21 studies). There was a significant reduction in blood levels of vitamin E in patients suffering from severe malaria, in comparison with those experiencing less severe forms of the disease (p < 0.01, Cohen's d: -0.56, 95% CI: -0.85-(-0.26), I2: 0%, 2 studies), but no variation in blood levels of vitamin E among patients suffering from either P. falciparum or P. vivax malaria (p = 0.13, Cohen's d: -1.15, 95% CI: -2.62-0.33, I2: 93.22%, 3 studies). In summary, the present study strongly suggests that vitamin E levels are significantly reduced in malaria patients, with a more pronounced decrease observed in cases of severe malaria. However, the type of malaria parasite, specifically P. falciparum or P. vivax, did not appear to influence the levels of vitamin E. This study highlights the potential role of vitamin E in the pathogenesis of malaria and suggests that improved vitamin E status might be beneficial for improving disease outcomes.

Increased Blood Concentrations of Malondialdehyde in Plasmodium Infection: A Systematic Review and Meta-Analysis

Several studies have evaluated the relationship between malondialdehyde (MDA) concentrations and Plasmodium infections; however, the findings remain inconclusive. This study synthesized differences in MDA concentrations among patients with different levels of clinical severity, uninfected controls, and different Plasmodium species. The research protocol was registered in PROSPERO (CRD42023393540). Systematic literature searches for relevant studies were performed using the Embase, MEDLINE, Ovid, ProQuest, PubMed, Scopus, and Google Scholar databases. Qualitative and quantitative syntheses (meta-analyses) of distinct MDA concentrations between the disease groups were performed. Twenty-three studies met the eligibility criteria and were included in the systematic review. Overall, MDA concentrations were significantly elevated in participants with malaria relative to uninfected controls (p < 0.01, Cohen d: 2.51, 95% confidence interval (CI): 1.88-3.14, I2: 96.22%, 14 studies). Increased MDA concentrations in participants with malaria compared with uninfected controls were found in studies that enrolled patients with P. falciparum malaria (p < 0.01, Cohen d: 2.50, 95% CI: 1.90-3.10, I2: 89.7%, 7 studies) and P. vivax malaria (p < 0.01, Cohen d: 3.70, 95% CI: 2.48-4.92, I2: 90.11%, 3 studies). Our findings confirm that MDA concentrations increase during Plasmodium infection, indicating a rise in oxidative stress and lipid peroxidation. Thus, MDA levels can be a valuable biomarker for evaluating these processes in individuals with malaria. However, further research is necessary to fully elucidate the intricate relationship between malaria, antioxidants, oxidative stress, and the specific role of MDA in the progression of malaria.

Secondary Metabolites Isolated from Artemisia afra and Artemisia annua and Their Anti-Malarial, Anti-Inflammatory and Immunomodulating Properties-Pharmacokinetics and Pharmacodynamics: A Review

There are over 500 species of the genus Artemisia in the Asteraceae family distributed over the globe, with varying potentials to treat different ailments. Following the isolation of artemisinin (a potent anti-malarial compound with a sesquiterpene backbone) from Artemisia annua, the phytochemical composition of this species has been of interest over recent decades. Additionally, the number of phytochemical investigations of other species, including those of Artemisia afra in a search for new molecules with pharmacological potentials, has increased in recent years. This has led to the isolation of several compounds from both species, including a majority of monoterpenes, sesquiterpenes, and polyphenols with varying pharmacological activities. This review aims to discuss the most important compounds present in both plant species with anti-malarial properties, anti-inflammatory potentials, and immunomodulating properties, with an emphasis on their pharmacokinetics and pharmacodynamics properties. Additionally, the toxicity of both plants and their anti-malaria properties, including those of other species in the genus Artemisia, is discussed. As such, data were collected via a thorough literature search in web databases, such as ResearchGate, ScienceDirect, Google scholar, PubMed, Phytochemical and Ethnobotanical databases, up to 2022. A distinction was made between compounds involved in a direct anti-plasmodial activity and those expressing anti-inflammatory and immunomodulating activities or anti-fever properties. For pharmacokinetics activities, a distinction was made between compounds influencing bioavailability (CYP effect or P-Glycoprotein effect) and those affecting the stability of pharmacodynamic active components.

Luffa cylindrica (Linn. M. J. Roem) Reduces Oxidative Stress In Vivo in Plasmodium berghei-Infected Albino Mice

Background: Malaria is endemic in sub-Saharan Africa, and oxidative stress has been implicated in malaria disease. Luffa cylindrica is an ethnomedicinal plant used to treat various diseases, including malaria. The oxidative stress-reducing potential of L. cylindrica in malaria-disease state of Plasmodium berghei NK-65 parasite-infected mice was carried out in vivo.

Methods: Mice were infected with P. berghei NK-65, and the effect of administration of methanolic leaves extract (100, 200, and 400 mg/kg b.w) of L. cylindrica on percentage parasitemia in blood smear, antioxidant enzymes (catalase CAT, superoxide dismutase SOD, glutathione-s-transferase GST), non-enzymatic antioxidant (reduced glutathione GSH) and malondialdehyde concentration in tissues (plasma, liver, kidneys, and spleen) of mice was investigated and compared to chloroquine and artesunate as reference antimalarial drugs. Phytochemical constituents of the extract were determined by standard methods.

Results: Saponins, tannins, terpenes, phenolics, flavonoids, alkaloids, and glycosides were the phytochemical constituents identified in the extract. The extract at three doses (100, 200, and 400 mg/kg b.w.) investigated caused a significant reduction (p < 0.05) of parasite growth with over 90% reduction in parasitemia level in mice infected with the parasite. The extract also ameliorated oxidative stress in mice by significantly (p < 0.05) increasing the activities of CAT, SOD, and GST in the studied tissues of mice. The level of malondialdehyde, a marker of oxidative stress in mice, was also significantly (p < 0.05) reduced by the extract. The results were comparable with chloroquine- and artesunate-treated groups.

Conclusion: The study concludes that L. cylindrica is an effective therapy for treating malaria and for the management of its oxidative stress-related complications due to its antioxidant properties.

Potential Benefits of Lycopene Consumption: Rationale for Using It as an Adjuvant Treatment for Malaria Patients and in Several Diseases

Malaria is a disease that affects thousands of people around the world every year. Its pathogenesis is associated with the production of reactive oxygen and nitrogen species (RONS) and lower levels of micronutrients and antioxidants. Patients under drug treatment have high levels of oxidative stress biomarkers in the body tissues, which limits the use of these drugs. Therefore, several studies have suggested that RONS inhibition may represent an adjuvant therapeutic strategy in the treatment of these patients by increasing the antioxidant capacity of the host. In this sense, supplementation with antioxidant compounds such as zinc, selenium, and vitamins A, C, and E has been suggested as part of the treatment. Among dietary antioxidants, lycopene is the most powerful antioxidant among the main carotenoids. This review aimed to describe the main mechanisms inducing oxidative stress during malaria, highlighting the production of RONS as a defense mechanism against the infection induced by the ischemia-reperfusion syndrome, the metabolism of the parasite, and the metabolism of antimalarial drugs. Furthermore, the effects of lycopene on several diseases in which oxidative stress is implicated as a cause are outlined, providing information about its mechanism of action, and providing an evidence-based justification for its supplementation in malaria.

Impact of Oxidative Stress on Risk of Death and Readmission in African Children With Severe Malaria: A Prospective Observational Study

BACKGROUND

We hypothesized that oxidative stress in Ugandan children with severe malaria is associated with mortality.

METHODS

We evaluated biomarkers of oxidative stress in children with cerebral malaria (CM, n = 77) or severe malarial anemia (SMA, n = 79), who were enrolled in a randomized clinical trial of immediate vs delayed iron therapy, compared with community children (CC, n = 83). Associations between admission biomarkers and risk of death during hospitalization or risk of readmission within 6 months were analyzed.

RESULTS

Nine children with CM and none with SMA died during hospitalization. Children with CM or SMA had higher levels of heme oxygenase-1 (HO-1) (P < .001) and lower superoxide dismutase (SOD) activity than CC (P < .02). Children with CM had a higher risk of death with increasing HO-1 concentration (odds ratio [OR], 6.07 [95% confidence interval {CI}, 1.17-31.31]; P = .03) but a lower risk of death with increasing SOD activity (OR, 0.02 [95% CI, .001-.70]; P = .03). There were no associations between oxidative stress biomarkers on admission and risk of readmission within 6 months of enrollment.

CONCLUSIONS

Children with CM or SMA develop oxidative stress in response to severe malaria. Oxidative stress is associated with higher mortality in children with CM but not with SMA.

CLINICAL TRIALS REGISTRATION

NCT01093989.

Ferroptosis participates in neuron damage in experimental cerebral malaria and is partially induced by activated CD8+ T cells

Cerebral malaria is the most serious complication of malaria infection, with 26% of surviving children having neurological sequelae, which may be caused by neuron damage, but the mechanism is not clear. Ferroptosis has been reported to play an important role in neuron damage in several nervous system diseases. However, the occurrence of ferroptosis in experimental cerebral malaria (ECM) pathogenesis is still unknown. In this study, we firstly detected increased levels of malondialdehyde (MDA) and iron, which are indicators of ferroptosis, in the cerebrum of ECM mice. Some important regulators of ferroptosis, including upregulated expression of transferrin receptor 1 (TfR1) and acyl-CoA synthetase long-chain family member 4 (ACSL4), and downregulation of glutathione peroxidase 4 (GPX4) levels, were also confirmed in ECM mice. Consistently, neuron damage, which was detected in the cerebrum of ECM mice, was positively correlated with reduced GPX4 expression and furtherly rescued by administration of the ferroptosis inhibitor ferrostatin-1 (Fer-1). In addition, primary neurons were damaged by activated CD8⁺ T cells, an effect that was also partially rescued by Fer-1 on amyloid precursor protein expression and mitochondrial membrane potential levels in vitro. Activated CD8⁺ T cells were also shown to infiltrate the cerebrum of ECM mice and upregulate TfR1 expression in primary neurons, which may be an important event for inducing ferroptosis in ECM. Altogether, we show that ferroptosis contributes to neuron damage in ECM pathogenesis, and activated CD8⁺ T cells may be important inducers of neuronal ferroptosis. Hence, targeting ferroptosis may be a promising adjuvant therapeutic strategy for neurological sequelae in patients with cerebral malaria.

Oxidative Stress in Malaria: Potential Benefits of Antioxidant Therapy

Malaria is an infectious disease and a serious public health problem in the world, with 3.3 billion people in endemic areas in 100 countries and about 200 million new cases each year, resulting in almost 1 million deaths in 2018. Although studies look for strategies to eradicate malaria, it is necessary to know more about its pathophysiology to understand the underlying mechanisms involved, particularly the redox balance, to guarantee success in combating this disease. In this review, we addressed the involvement of oxidative stress in malaria and the potential benefits of antioxidant supplementation as an adjuvant antimalarial therapy.

Anti-plasmodial, Cytotoxic and Antioxidant Activities of Selected Ghanaian Medicinal Plants

Malaria affects about half of the world's population. The sub-Saharan African region is the most affected. Plant natural products have been a major source of antimalarial drugs; the first (quinine) and present (artemisinin) antimalarials are of natural product origin. Some secondary metabolites demonstrate adjuvant antioxidant effects and selective activity. The focus of this study was to investigate the anti-plasmodial activity, cytotoxicities and antioxidant properties of eight (8) Ghanaian medicinal plants. The anti-plasmodial activity was determined using the SYBR green assay and the tetrazolium-based colorimetric assay (MTT) was employed to assess cytotoxicity of extracts to human RBCs and HL-60 cells. Antioxidant potential of plant extracts was evaluated using Folin-Ciocalteu and superoxide dismutase assays. Phytochemical contstituents of the plant extracts were also assessed. All the extracts demonstrated anti-plasmodial activities at concentrations <50 μg/ml. Parkia clappertoniana and Terminalia ivorensis elicited the strongest anti-plasmodial activities with 50% inhibitory concentrations (IC₅₀) of 1.13 μg/ml and 0.95 μg/ml, respectively. This is the first report on anti-plasmodial activities of Baphia nitida, Tabernaemontana crassa and Treculia Africana. T. Africana showed moderate anti-plasmodial activity with IC₅₀ value of 6.62 µg/mL. Extracts of P. clappertoniana, T. Africana and T. ivorensis (0.4 mg/mL) showed >50% antioxidant effect (SOD). The extracts were not cytotoxicity towards RBCs at the concentration tested (200 μg/ml) but were weakly cytotoxic to HL-60 cell. Selectivity indices of most of the extracts were greater than 10. Our results suggest that most of the plant extracts have strong anti-plasmodial activity and antioxidant activity which warrants further investigations.

Haematological response in experimental human Plasmodium falciparum and Plasmodium vivax malaria

Background

Malaria-associated anaemia, arising from symptomatic, asymptomatic and submicroscopic infections, is a significant cause of morbidity worldwide. Induced blood stage malaria volunteer infection studies (IBSM-VIS) provide a unique opportunity to evaluate the haematological response to early Plasmodium falciparum and Plasmodium vivax infection.

Methods

This study was an analysis of the haemoglobin, red cell counts, and parasitaemia data from 315 participants enrolled in IBSM-VIS between 2012 and 2019, including 269 participants inoculated with the 3D7 strain of P. falciparum (Pf3D7), 15 with an artemisinin-resistant P. falciparum strain (PfK13) and 46 with P. vivax. Factors associated with the fractional fall in haemoglobin (Hb-FF) were evaluated, and the malaria-attributable erythrocyte loss after accounting for phlebotomy-related losses was estimated. The relative contribution of parasitized erythrocytes to the malaria-attributable erythrocyte loss was also estimated.

Results

The median peak parasitaemia prior to treatment was 10,277 parasites/ml (IQR 3566–27,815), 71,427 parasites/ml [IQR 33,236–180,213], and 34,840 parasites/ml (IQR 13,302–77,064) in participants inoculated with Pf3D7, PfK13, and P. vivax, respectively. The median Hb-FF was 10.3% (IQR 7.8–13.3), 14.8% (IQR 11.8–15.9) and 11.7% (IQR 8.9–14.5) in those inoculated with Pf3D7, PfK13 and P. vivax, respectively, with the haemoglobin nadir occurring a median 12 (IQR 5–21), 15 (IQR 7–22), and 8 (IQR 7–15) days following inoculation. In participants inoculated with P. falciparum, recrudescence was associated with a greater Hb-FF, while in those with P. vivax, the Hb-FF was associated with a higher pre-treatment parasitaemia and later day of anti-malarial treatment. After accounting for phlebotomy-related blood losses, the estimated Hb-FF was 4.1% (IQR 3.1–5.3), 7.2% (IQR 5.8–7.8), and 4.9% (IQR 3.7–6.1) in participants inoculated with Pf3D7, PfK13, and P. vivax, respectively. Parasitized erythrocytes were estimated to account for 0.015% (IQR 0.006–0.06), 0.128% (IQR 0.068–0.616) and 0.022% (IQR 0.008–0.082) of the malaria-attributable erythrocyte loss in participants inoculated with Pf3D7, PfK13, and P. vivax, respectively.

Conclusion

Early experimental P. falciparum and P. vivax infection resulted in a small but significant fall in haemoglobin despite parasitaemia only just at the level of microscopic detection. Loss of parasitized erythrocytes accounted for < 0.2% of the total malaria-attributable haemoglobin loss.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-04003-7.

Oxidative Stress and Pathogenesis in Malaria

Malaria is a highly inflammatory and oxidative disease. The production of reactive oxygen species by host phagocytes is an essential component of the host response to Plasmodium infection. Moreover, host oxidative enzymes, such as xanthine oxidase, are upregulated in malaria patients. Although increased production of reactive oxygen species contributes to the clearance of the parasite, excessive amounts of these free radicals can mediate inflammation and cause extensive damage to host cells and tissues, probably contributing to severe pathologies. Plasmodium has a variety of antioxidant enzymes that allow it to survive amidst this oxidative onslaught. However, parasitic degradation of hemoglobin within the infected red blood cell generates free heme, which is released at the end of the replication cycle, further aggravating the oxidative burden on the host and possibly contributing to the severity of life-threatening malarial complications. Additionally, the highly inflammatory response to malaria contributes to exacerbate the oxidative response. In this review, we discuss host and parasite-derived sources of oxidative stress that may promote severe disease in P. falciparum infection. Therapeutics that restore and maintain oxidative balance in malaria patients may be useful in preventing lethal complications of this disease.

Transcriptome-based analysis of blood samples reveals elevation of DNA damage response, neutrophil degranulation, cancer and neurodegenerative pathways in Plasmodium falciparum patients

BACKGROUND

Malaria caused by Plasmodium falciparum results in severe complications including cerebral malaria (CM) especially in children. While the majority of falciparum malaria survivors make a full recovery, there are reports of some patients ending up with neurological sequelae or cognitive deficit.

METHODS

An analysis of pooled transcriptome data of whole blood samples derived from two studies involving various P. falciparum infections, comprising mild malaria (MM), non-cerebral severe malaria (NCM) and CM was performed. Pathways and gene ontologies (GOs) elevated in the distinct P. falciparum infections were determined.

RESULTS

In all, 2876 genes were expressed in common between the 3 forms of falciparum malaria, with CM having the least number of expressed genes. In contrast to other research findings, the analysis from this study showed MM share similar biological processes with cancer and neurodegenerative diseases, NCM is associated with drug resistance and glutathione metabolism and CM is correlated with endocannabinoid signalling and non-alcoholic fatty liver disease (NAFLD). GO revealed the terms biogenesis, DNA damage response and IL-10 production in MM, down-regulation of cytoskeletal organization and amyloid-beta clearance in NCM and aberrant signalling, neutrophil degranulation and gene repression in CM. Differential gene expression analysis between CM and NCM showed the up-regulation of neutrophil activation and response to herbicides, while regulation of axon diameter was down-regulated in CM.

CONCLUSIONS

Results from this study reveal that P. falciparum-mediated inflammatory and cellular stress mechanisms may impair brain function in MM, NCM and CM. However, the neurological deficits predominantly reported in CM cases could be attributed to the down-regulation of various genes involved in cellular function through transcriptional repression, axonal dysfunction, dysregulation of signalling pathways and neurodegeneration. It is anticipated that the data from this study, might form the basis for future hypothesis-driven malaria research.

Anti-Malarial and Anti-Lipid Peroxidation Activities of Deferiprone-Resveratrol Hybrid in Plasmodium berghei-Infected Mice

Simple Summary

Malaria remains a public health problem in tropical and subtropical countries. The emergence of malaria parasite resistance to antimalarial drugs has been recently considered a serious issue. Alternative compounds have become an important therapeutic strategy to achieve malaria treatment. Iron chelators are widely used for the treatment of iron overload patients. The iron chelators also reveal an inhibitory effect on malaria parasite growth by depriving the parasite intracellular iron. This study presented the potential of the novel hybrid iron chelator, deferiprone-resveratrol hybrid on the inhibition of malaria parasite growth, the improvement of hematological parameters and the alleviatation of oxidative tissue damage in malaria-infected mice. Deferiprone-resveratrol hybrid would be used as a therapeutic/preventive compound to increase the efficacy of treatment and eliminate an antimalarial drug resistance.

Abstract

Iron is essential for all organisms including fast-dividing malarial parasites. Inversely, iron chelators can inhibit parasite growth through the inhibition of DNA synthesis and can ameliorate oxidative cell damage. Deferiprone (DFP)-resveratrol (RVT) hybrid (DFP-RVT) is a lipophilic anti-oxidative, iron-chelating agent that has displayed potent neuroprotective and anti-plasmodium activities in vitro. The goal of this work was to investigate the inhibitory effects of DFP-RVT on parasite growth and oxidative stress levels during malaria infections. Mice were intraperitoneally infected with P. berghei and orally administered with DFP, DFP-RVT and pyrimethamine for 4 d. The percentage of parasitemia was determined using Giemsa’s staining/microscopic examination. Amounts of the lipid-peroxidation product, thiobarbituric acid-reactive substance (TBARS), were determined in both plasma and liver tissue. In our findings, DFP-RVT exhibited a greater potent inhibitory effect and revealed an improvement in anemia and liver damage in infected mice than DFP. To this point, the anti-malarial activity was found to be associated with anti-RBC hemolysis and the liver weight index. In addition, plasma and liver TBARS levels in the DFP-RVT-treated mice were lower than those in DFP-treated mice. Thus, DFP-RVT could exert anti-plasmodium, anti-hemolysis and anti-lipid peroxidation activities to a better degree than DFP in P. berghei-infected mice.

Antioxidant and antimalarial properties of Sophora exigua Craib. root extract in Plasmodium berghei-infected mice

Background

Sophora exigua Craib. is commonly used in Thailand to reduce fever and increase postpartum breast milk production in women who have hypogalactia. However, there has been no report on the antioxidant and antimalarial properties of this plant. This study aimed to investigate the antioxidant and antimalarial activities of S. exigua root extract and to evaluate its acute toxicity in mice to confirm its safety.

Methods

The in vitro antioxidant activities were determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide radical, and hydroxyl radical scavenging assays. The in vivo antioxidant activities were determined by detecting the malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in the livers of malaria-infected mice. The in vivo antimalarial activity was determined by Peters’ 4-day suppressive test in mice infected with Plasmodium berghei ANKA and orally administered S. exigua root aqueous and ethanolic extracts at different doses (200, 400, and 600 mg/kg body weight). In addition, the acute oral toxicity of the plant extracts was assessed in mice at a dose of 2000 mg/kg body weight.

Results

The ethanolic extract of S. exigua root exhibited inhibition of DPPH radicals, superoxide anions, and hydroxyl radicals, with half maximal inhibitory concentration (IC₅₀) values of 24.63 ± 1.78, 129.78 ± 0.65, and 30.58 ± 1.19 μg/ml, respectively. Similarly, research on the in vivo antioxidant activity indicated that the ethanolic extract of S. exigua root exerted a stronger effect than the aqueous extract. The aqueous extract at doses of 200, 400, and 600 mg/kg had stronger antimalarial activity than the ethanolic extract. The aqueous extract at 600 mg/kg exhibited 60.46% suppression of parasitemia. Increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) and blood urea nitrogen (BUN) were detected in the mice treated with 2000 mg/kg ethanolic extract, which was related to the results of histopathological analysis of liver tissue, showing ballooning degeneration of hepatocytes, diffuse hepatic hemorrhage, and infiltration of inflammatory cells.

Conclusions

This study demonstrated that the ethanolic S. exigua root extract possessed antioxidant properties, and the aqueous extract also had antimalarial activity. Therefore, this plant is an alternative source of new antioxidant and antimalarial agents.

Oxidative and nitrosative stresses in cerebral malaria: can we target them to avoid a bad prognosis?

There is currently a global effort to reduce malaria morbidity and mortality. However, malaria still results in the deaths of thousands of people every year. Malaria is caused by Plasmodium spp., parasites transmitted through the bite of an infected female Anopheles mosquito. Treatment timing plays a decisive role in reducing mortality and sequelae associated with the severe forms of the disease such as cerebral malaria (CM). The available antimalarial therapy is considered effective but parasite resistance to these drugs has been observed in some countries. Antimalarial drugs act by increasing parasite lysis, especially through targeting oxidative stress pathways. Here we discuss the roles of reactive oxygen species and reactive nitrogen intermediates in CM as a result of host-parasite interactions. We also present evidence of the potential contribution of oxidative and nitrosative stress-based antimalarial drugs to disease treatment and control.

Synthesis and biological evaluation of Val-Val dipeptide-sulfonamide conjugates

Novel Val-Val dipeptide-benzenesulfonamide conjugates were reported in this study. These were achieved by a condensation reaction of p-substituted benzenesulfonamoyl alkanamides with 2-amino-4-methyl-N-substituted phenyl butanamide using classical peptide-coupling reagents. The compounds were characterized using Fourier transform infrared, ¹ H-nuclear magnetic resonance (NMR), ¹³ C-NMR, and electrospray ionization-high-resolution mass spectrometry spectroscopic techniques. As predicted from in silico studies, the Val-Val dipeptide-benzenesulfonamide conjugates exhibited antimalarial and antioxidant properties that were analogous to the standard drug. The synthesized compounds were evaluated for in vivo antimalarial activity against Plasmodium berghei. The hematological analysis was also conducted on the synthesized compounds. At 50 mg/kg body weight, compounds 8a, 8d, and 8g-i inhibited the multiplication of the parasite by 48-54% on Day 7 of posttreatment exposure, compared with the 67% reduction with artemisinin. All the synthesized dipeptides had a good antioxidant property, but it was less when compared with vitamin C. The dipeptides reported herein showed the ability to reduce oxidative stress arising from the malaria parasite.

Malaria inflammation by xanthine oxidase-produced reactive oxygen species

Malaria is a highly inflammatory disease caused by Plasmodium infection of host erythrocytes. However, the parasite does not induce inflammatory cytokine responses in macrophages in vitro and the source of inflammation in patients remains unclear. Here, we identify oxidative stress, which is common in malaria, as an effective trigger of the inflammatory activation of macrophages. We observed that extracellular reactive oxygen species (ROS) produced by xanthine oxidase (XO), an enzyme upregulated during malaria, induce a strong inflammatory cytokine response in primary human monocyte-derived macrophages. In malaria patients, elevated plasma XO activity correlates with high levels of inflammatory cytokines and with the development of cerebral malaria. We found that incubation of macrophages with plasma from these patients can induce a XO-dependent inflammatory cytokine response, identifying a host factor as a trigger for inflammation in malaria. XO-produced ROS also increase the synthesis of pro-IL-1β, while the parasite activates caspase-1, providing the two necessary signals for the activation of the NLRP3 inflammasome. We propose that XO-produced ROS are a key factor for the trigger of inflammation during malaria.

Oxidative Stress and Hemoglobin Level of Complicated and Uncomplicated Malaria Cases among Children: A Cross-Sectional Study in Kumasi Metropolis, Ghana

Introduction

Malaria is a leading cause of mortality among children below 5 years in Ghana. Its parasites are known to cause the degradation of hemoglobin, resulting in the production of reactive oxygen species and hence oxidant stress. Therefore, this study was carried out to compare the levels of oxidative stress between children with complicated and uncomplicated malaria infection in Kumasi, Ghana.

Method

Subjects were recruited from hospitals in the Kumasi Metropolis. This was a cross-sectional study, involving 17 complicated malaria subjects, 51 uncomplicated malaria subjects, and 15 nonparasitemic subjects. The rapid diagnostic test (RDT) was used to determine presence or absence of falciparum malaria among the study participants. Blood samples from subjects were used to determine hemoglobin, malondialdehyde (MDA), and vitamin C levels.

Results

Majority of the subjects (67.5%) were within the age of 0-5 years. The mean age (±SD) of uncomplicated malaria subjects was 4.32 (±2.81) years, while that of complicated malaria was 4.27 (±2.96). Mean levels of HB decreased significantly in the following order: control subjects > uncomplicated malaria subjects > complicated malaria subjects (p<0.0001). Mean levels of MDA were significantly lower in control subjects compared to complicated malaria subjects (4.62±1.85 versus 6.68±0.70, p=0.0008) and also lowered in uncomplicated malaria subjects compared to complicated malaria (4.50±1.58 versus 6.68±0.70, p<0.0001). There was a statistically significant reduced mean level of vitamin C (p=0.036) in the following order: control subjects > uncomplicated malaria > complicated malaria subjects. However, for the complicated malaria cases, there were significantly higher mean vitamin C levels in females than in males (p<0.001).

Conclusion

Malaria progression increases MDA levels and decreases the ascorbate (vitamin C) and hemoglobin levels. It is recommended that future studies should investigate changes in other antioxidant vitamins, like vitamins A and E.

TRPV1 Contributes to Cerebral Malaria Severity and Mortality by Regulating Brain Inflammation

Transient receptor potential vanilloid 1 (TRPV1) is a Ca⁺²-permeable channel expressed on neuronal and nonneuronal cells, known as an oxidative stress sensor. It plays a protective role in bacterial infection, and recent findings indicate that this receptor modulates monocyte populations in mice with malaria; however, its role in cerebral malaria progression and outcome is unclear. By using TRPV1 wild-type (WT) and knockout (KO) mice, the importance of TRPV1 to this cerebral syndrome was investigated. Infection with Plasmodium berghei ANKA decreased TRPV1 expression in the brain. Mice lacking TRPV1 were protected against Plasmodium-induced mortality and morbidity, a response that was associated with less cerebral swelling, modulation of the brain expression of endothelial tight-junction markers (junctional adhesion molecule A and claudin-5), increased oxidative stress (via inhibition of catalase activity and increased levels of H₂O₂, nitrotyrosine, and carbonyl residues), and diminished production of cytokines. Plasmodium load was not significantly affected by TRPV1 ablation. Repeated subcutaneous administration of the selective TRPV1 antagonist SB366791 after malaria induction increased TRPV1 expression in the brain tissue and enhanced mouse survival. These data indicate that TRPV1 channels contribute to the development and outcome of cerebral malaria.

Oral administration of Coenzyme Q10 protects mice against oxidative stress and neuro-inflammation during experimental cerebral malaria

In animal model of experimental cerebral malaria (ECM), the genesis of neuropathology is associated with oxidative stress and inflammatory mediators. There is limited progress in the development of new approaches to the treatment of cerebral malaria. Here, we tested whether oral supplementation of Coenzyme Q₁₀ (CoQ₁₀) would offer protection against oxidative stress and brain associated inflammation following Plasmodium berghei ANKA (PbA) infection in C57BL/6 J mouse model. For this purpose, one group of C57BL/6 mice was used as control; second group of mice were orally supplemented with 200 mg/kg CoQ₁₀ and then infected with PbA and the third group was PbA infected alone. Clinical, biochemical, immunoblot and immunological features of ECM was monitored. We observed that oral administration of CoQ₁₀ for 1 month and after PbA infection was able to improve survival, significantly reduced oedema, TNF-α and MIP-1β gene expression in brain samples in PbA infected mice. The result also shows the ability of CoQ₁₀ to reduce cholesterol and triglycerides lipids, levels of matrix metalloproteinases-9, angiopoietin-2 and angiopoietin-1 in the brain. In addition, CoQ₁₀ was very effective in decreasing NF-κB phosphorylation. Furthermore, CoQ₁₀ supplementation abrogated Malondialdehyde, and 8-OHDG and restored cellular glutathione. These results constitute the first demonstration that oral supplementation of CoQ₁₀ can protect mice against PbA induced oxidative stress and neuro-inflammation usually observed in ECM. Thus, the need to study CoQ₁₀ as a candidate of antioxidant and immunomodulatory molecule in ECM and testing it in clinical studies either alone or in combination with antimalaria regimens to provide insight into a potential translatable therapy.

Correlation of malaria parasitaemia with peripheral blood monocyte to lymphocyte ratio as indicator of susceptibility to severe malaria in Ghanaian children

Background

Even though malaria is generally on the decline due extensive control and elimination efforts, it still remains a public health problem for over 40% of the world’s population. During the course of malaria infection, parasites and red blood cells come under oxidative stress and there is host immune response in an attempt to protect the red blood cells. The frequency of monocytes and lymphocytes in peripheral blood might, therefore, be expected to reflect the state of an individual’s immune response to the infection. Circulating monocytes and lymphocytes could therefore serve as an index in relation to malaria parasitaemia. The purpose of this study was to determine whether the relative count of monocytes to lymphocytes in peripheral blood (M:L ratio) can predict parasitaemia and, therefore, the severity of malaria infection.

Methods

Two millilitre of venous blood sample were taken from participants by venisection into anticoagulant tubes. Thick and thin blood films were made and stained with Giemsa and examined for malaria parasites. Whole blood specimen were analysed for full blood count using ABX Pentra 60 C+ automated haematological analyzer. Data was entered into Microsoft Word and analysed using Statistical Package for Social Sciences (SPSS, Version 20.0) and Graphpad prism. Spearman’s correlation was used to determine correlation between occurrences of clinical malaria and the monocytes and lymphocytes ratio. Statistical significance was taken as p ≤ 0.05 with 95% confidence interval.

Results

The study comprised of 1629 (m = 896; f = 733) children up to 5 years presenting with clinical malaria as cases and 445 (m = 257; f = 188) apparently healthy children as controls. The results indicated that there was a significant positive correlation between the monocytes to lymphocytes ratio and the presence of parasites (p = 0.04) and the level of parasitaemia within the age group of 0–3 years (p = 0.02) and 4–5 years (p = 0.03).

Conclusions

The monocyte to lymphocyte ratio obtained correlated positively with the presence of malaria as well as the level of parasitaemia. The outcome of this work implies that monocyte to lymphocyte ratio can be used to predict the level of parasitaemia and together with other factors, the development of severe malaria.

Cerebral Malaria Causes Enduring Behavioral and Molecular Changes in Mice Brain Without Causing Gross Histopathological Damage

Malaria, parasitic disease considered a major health public problem, is caused by Plasmodium protozoan genus and transmitted by the bite of infected female Anopheles mosquito genus. Cerebral malaria (CM) is the most severe presentation of malaria, caused by P. falciparum and responsible for high mortality and enduring development of cognitive deficits which may persist even after cure and cessation of therapy. In the present study we evaluated selected behavioral, neurochemical and neuropathologic parameters after rescue from experimental cerebral malaria caused by P. berghei ANKA in C57BL/6 mice. Behavioral tests showed impaired nest building activity as well as increased marble burying, indicating that natural behavior of mice remains altered even after cure of infection. Regarding the neurochemical data, we found decreased α2/α3 Na⁺,K⁺-ATPase activity and increased immunoreactivity of phosphorylated Na⁺,K⁺-ATPase at Ser⁹⁴³ in cerebral cortex after CM. In addition, [³H]-Flunitrazepam binding assays revealed a decrease of benzodiazepine/GABA_A receptor binding sites in infected animals. Moreover, in hippocampus, dot blot analysis revealed increased levels of protein carbonyls, suggesting occurrence of oxidative damage to proteins. Interestingly, no changes in the neuropathological markers Fluoro-Jade C, Timm staining or IBA-1 were detected. Altogether, present data indicate that behavioral and neurochemical alterations persist even after parasitemia clearance and CM recovery, which agrees with available clinical findings. Some of the molecular mechanisms reported in the present study may underlie the behavioral changes and increased seizure susceptibility that persist after recovery from CM and may help in the future development of therapeutic strategies for CM sequelae.

Anti-plasmodial and anti-inflammatory activities of cyclotide-rich extract and fraction of Oldenlandia affinis (R. & S.) D.C. (Rubiaceae)

BACKGROUND

Oldenlandia affinis, commonly called 'kalata-kalata', a versatile plant used locally to treat malaria fever in some parts of sub-Saharan Africa was investigated for anti-plasmodial and anti-inflammatory activities.

OBJECTIVE

The study was designed to evaluate the antiplasmodial as well as anti-inflammatory activities of whole extract and cyclotide-rich fraction of Oldenlandia affinis.

METHOD

The dichloromethane-methanol extract (ODE) of the plant, O. affinis was investigated for suppressive and curative antiplasmodial activities against Plasmodium berghei in mice. ODE and the cyclotide-rich fraction (CRF) was investigated for chronic and acute anti-inflammatory activities in rat models of inflammation. Inhibition of pro-inflammatory mediators was studied in RAW264.7 macrophages.

RESULTS

ODE exhibited significant (p<0.05) reduction in mean parasitaemia in both the suppressive and curative models of Plasmodium berghei infection in mice.Administration of ODE(100, 200, or 400 mg/kg) and CRF (100, 200, or 400 mg/kg) produced significant inhibition of rodent models of acute and chronic inflammation . This observation is supported by the significant (P<0.05) inhibition of pro-inflammatory mediators, inducible nitric oxide (iNO) and tumour necrosis factor-alpha (TNF-α), and the reactive radical scavenging activities in RAW264.7 macrophages.

CONCLUSION

These findings could explain, at least in part, the successes reported in the use of the herb, Oldenlandia affinis in the traditional treatment of malaria fever.

Protein Carbonyl as a Biomarker of Oxidative Stress in Severe Leptospirosis, and Its Usefulness in Differentiating Leptospirosis from Dengue Infections

Pathogenesis of disease severity in leptospirosis is not clearly understood whether it is due to direct damage by pathogen or by adverse immune responses. Knowledge on biomarkers of oxidative stress which could be used in identifying patients with severe illness has shown to be of great value in disease management. Thus, the main aim of this study was to assess the damage to serum proteins and lipids, and their significance as biomarkers of oxidative stress in severe leptospirosis. In regions endemic for both leptospirosis and dengue, leptospirosis cases are often misdiagnosed as dengue during dengue epidemics. Therefore, the second aim was to assess the potential of the oxidative stress markers in differentiating severe leptospirosis from critical phase dengue. We measured serum antioxidants (uric acid and bilirubin), total antioxidant capacity (AOC), protein carbonyl (PC) and lipid hydroperoxide (LP) in patients with severe leptospirosis (n = 60), mild leptospirosis (n = 50), dengue during the critical phase (n = 30) and in healthy subjects (n = 30). All patient groups had similar total antioxidant capacity levels. However, the presence of significantly high uric acid and total bilirubin levels may reflect the degree of renal and hepatic involvement seen in severe leptospirosis patients (p<0.02). Serum PC and LP levels were significantly higher in leptospirosis patients compared to critical phase dengue infections (p<0.005). Moreover, high serum PC levels appear to differentiate SL from DC [area under the curve (AUC) = 0.96; p<0.001]. Serum PC may be a reliable biomarker of oxidative damage to serum proteins to identify severe leptospirosis patients (AUC = 0.99) and also to differentiate severe leptospirosis from mild cases (AUC = 0.78; p<0.005) indicating its contribution to pathogenesis. Use of serum PC as an indicator of leptospirosis severity and as an oxidative stress biomarker in differentiating leptospirosis from dengue would provide the opportunity to save lives via prompt patient management.

Increased Oxidative Stress and Inflammation Independent of Body Adiposity in Diabetic and Nondiabetic Controls in falciparum Malaria

Information on the extent to which oxidative stress and inflammation occur in the presence of falciparum malaria and type 2 diabetes mellitus in the same individual is limited. This study sought to investigate the extent of inflammation and oxidative stress in adult uncomplicated malaria by measuring fasting levels of lipid peroxides, C-reactive protein (CRP), and total antioxidant power (TAP) before and during falciparum malaria, in 100 respondents with type 2 diabetes and 100 age-matched controls in the Cape Coast metropolis of Ghana. Also, body adiposity index, body mass index, and waist-to-hip ratio were computed. Before and during falciparum malaria, diabetes patients exhibited higher (P < 0.05) levels of CRP and peroxides than controls but TAP and BAI were comparable (P > 0.05) between the two groups. Baseline CRP correlated positively (r = 0.341, P = 0.002) with peroxide only in the diabetic group. During malaria, TAP level in both study groups declined (P < 0.05) by 80% of their baseline levels. CRP correlated negatively (r = −0.352, P = 0.011) with TAP in the control but not the diabetic group. Uncomplicated falciparum malaria elevated inflammation and peroxidation but decreased antioxidant power independent of adiposity. This finding may have implication on cardiovascular health.

Protective Effect of Aqueous Crude Extract of Neem (Azadirachta indica) Leaves on Plasmodium berghei-Induced Renal Damage in Mice

Malaria is a major public health problem in the world because it can cause of death in patients. Malaria-associated renal injury is associated with 45% of mortality in adult patients hospitalized with severe form of the disease. Therefore, new plant extracts to protect against renal injury induced by malaria infection are urgently needed. In this study, we investigated the protective effect of aqueous crude extract of Azadirachta indica (neem) leaves on renal injury induced by Plasmodium berghei ANKA infection in mice. ICR mice were injected intraperitoneally with 1 × 10⁷ parasitized erythrocytes of PbANKA, and neem extracts (500, 1,000, and 2,000 mg/kg) were given orally for 4 consecutive days. Plasma blood urea nitrogen (BUN) and creatinine levels were subsequently measured. Malaria-induced renal injury was evidenced as marked increases of BUN and creatinine levels. However, the oral administration of neem leaf extract to PbANKA infected mice for 4 days brought back BUN and creatinine levels to near normalcy, and the highest activity was observed at doses of 1,000 and 2,000 mg/kg. Additionally, no toxic effects were found in normal mice treated with this extract. Hence, neem leaf extract can be considered a potential candidate for protection against renal injury induced by malaria.

Effect of Plasmodium falciparum malaria parasites on haematological parameters in Ghanaian children

Malaria is hyper-endemic in Ghana. Haematological alterations in the disease pathology may offer complimentary criteria to improve clinical and microscopy diagnosis. Our primary outcome was to evaluate haematological parameters in children with Plasmodium falciparum infections and report their predictive risk and diagnostic performance for malaria infections in Ghana. Haematological data, including thin and thick blood films were examined for children less than 12 years of age in a multicenter-based active case finding approach. Haematological changes were common in P. falciparum infected children and more pronounced in severe malaria cases. More so, a unit increase in parasiteamia increased the odds for severe malaria infection by 93 % [OR, 95 % CI: 1.93 (1.28-2.91); P value = 0.02]. In multivariate regression, low haemoglobin was a significant haematological change in predicting P. falciparum infections [OR, 95 % CI: 3.20 (1.26-7.09); P value = 0.001]. Low haemoglobin levels <11 g/dl was the most reliable indicator for P. falciparum infections [with a sensitivity of (64 %), specificity (71 %), positive predictive value (83 %) and likelihood ratio (2.2)]-even when evaluated in combination with leucocytosis, lymphocytopaenia and high neutrophil counts >7,500 µL. In malaria endemic settings, low haemoglobin concentration (<11 g/dl) in children with febrile illness should prompt a more diligent search for the malarial parasite to limit the misuse and abuse of anti-malarial drugs.

Blood oxidative stress markers and Plasmodium falciparum malaria in non-immune African children

Converging in vitro evidence and clinical data indicate that oxidative stress may play important roles in Plasmodium falciparum malaria, notably in the pathogenesis of severe anaemia. However, oxidative modifications of the red blood cell (RBC)-membrane by 4-hydroxynonenal (4-HNE) and haemoglobin-binding, previously hypothesized to contribute mechanistically to the pathogenesis of clinical malaria, have not yet been tested for clinical significance. In 349 non-immune Mozambican newborns recruited in a double-blind placebo-controlled chemoprophylaxis trial, oxidative markers including 4-HNE-conjugates and membrane-bound haemoglobin were longitudinally assessed from 2·5 to 24 months of age, at first acute malaria episode and in convalescence. During acute malaria, 4-HNE-conjugates were shown to increase significantly in parasitized and non-parasitized RBCs. In parallel, advanced oxidation protein products (AOPP) rose in plasma. 4-HNE-conjugates correlated with AOPP and established plasma but not with RBC oxidative markers. High individual levels of 4-HNE-conjugates were predictive for increased malaria incidence rates in children until 2 years of life and elevated 4-HNE-conjugates in convalescence accompanied sustained anaemia after a malaria episode, indicating 4-HNE-conjugates as a novel patho-mechanistic factor in malaria. A second oxidative marker, haemoglobin binding to RBC-membranes, hypothesized to induce clearing of RBCs from circulation, was predictive for lower malaria incidence rates. Further studies will show whether or not higher membrane-haemoglobin values at the first malaria episode may provide protection against malaria.

PPARγ agonists improve survival and neurocognitive outcomes in experimental cerebral malaria and induce neuroprotective pathways in human malaria

Cerebral malaria (CM) is associated with a high mortality rate, and long-term neurocognitive impairment in approximately one third of survivors. Adjunctive therapies that modify the pathophysiological processes involved in CM may improve outcome over anti-malarial therapy alone. PPARγ agonists have been reported to have immunomodulatory effects in a variety of disease models. Here we report that adjunctive therapy with PPARγ agonists improved survival and long-term neurocognitive outcomes in the Plasmodium berghei ANKA experimental model of CM. Compared to anti-malarial therapy alone, PPARγ adjunctive therapy administered to mice at the onset of CM signs, was associated with reduced endothelial activation, and enhanced expression of the anti-oxidant enzymes SOD-1 and catalase and the neurotrophic factors brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in the brains of infected mice. Two months following infection, mice that were treated with anti-malarials alone demonstrated cognitive dysfunction, while mice that received PPARγ adjunctive therapy were completely protected from neurocognitive impairment and from PbA-infection induced brain atrophy. In humans with P. falciparum malaria, PPARγ therapy was associated with reduced endothelial activation and with induction of neuroprotective pathways, such as BDNF. These findings provide insight into mechanisms conferring improved survival and preventing neurocognitive injury in CM, and support the evaluation of PPARγ agonists in human CM.

Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection that is associated with long-term neurocognitive impairment in about a third of survivors even when optimal anti-malarial therapy is used. Since both the parasite and the host immune response to infection play a role in the development of CM, adjunctive therapies that modulate the host response, given in conjunction with anti-parasitic therapy, may improve survival and prevent neurocognitive injury. Here we examine the effects of PPARγ agonists on neurocongitive injury using a mouse model of CM. We demonstrate that PPARγ agonists, when administered with anti-malarials, protected mice from developing brain atrophy and neurocognitive impairment. This was associated with induction of anti-oxidant and neuroprotective pathways in the brains of infected mice. We also observed the same neuroprotective pathways induced in patients with falciparum malaria that received PPARγ adjunctive therapy. Our findings suggest that PPARγ agonists may be valuable in the treatment and prevention of CM-induced neurocognitive injury, and support the testing of PPARγ agonists in patients with CM.

Tempol, an intracellular antioxidant, inhibits tissue factor expression, attenuates dendritic cell function, and is partially protective in a murine model of cerebral malaria

Background

The role of intracellular radical oxygen species (ROS) in pathogenesis of cerebral malaria (CM) remains incompletely understood.

Methods and Findings

We undertook testing Tempol—a superoxide dismutase (SOD) mimetic and pleiotropic intracellular antioxidant—in cells relevant to malaria pathogenesis in the context of coagulation and inflammation. Tempol was also tested in a murine model of CM induced by Plasmodium berghei Anka infection. Tempol was found to prevent transcription and functional expression of procoagulant tissue factor in endothelial cells (ECs) stimulated by lipopolysaccharide (LPS). This effect was accompanied by inhibition of IL-6, IL-8, and monocyte chemoattractant protein (MCP-1) production. Tempol also attenuated platelet aggregation and human promyelocytic leukemia HL60 cells oxidative burst. In dendritic cells, Tempol inhibited LPS-induced production of TNF-α, IL-6, and IL-12p70, downregulated expression of co-stimulatory molecules, and prevented antigen-dependent lymphocyte proliferation. Notably, Tempol (20 mg/kg) partially increased the survival of mice with CM. Mechanistically, treated mice had lowered plasma levels of MCP-1, suggesting that Tempol downmodulates EC function and vascular inflammation. Tempol also diminished blood brain barrier permeability associated with CM when started at day 4 post infection but not at day 1, suggesting that ROS production is tightly regulated. Other antioxidants—such as α-phenyl N-tertiary-butyl nitrone (PBN; a spin trap), MnTe-2-PyP and MnTBAP (Mn-phorphyrin), Mitoquinone (MitoQ) and Mitotempo (mitochondrial antioxidants), M30 (an iron chelator), and epigallocatechin gallate (EGCG; polyphenol from green tea) did not improve survival. By contrast, these compounds (except PBN) inhibited Plasmodium falciparum growth in culture with different IC_50s. Knockout mice for SOD1 or phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (gp91^phox–/–) or mice treated with inhibitors of SOD (diethyldithiocarbamate) or NADPH oxidase (diphenyleneiodonium) did not show protection or exacerbation for CM.

Conclusion

Results with Tempol suggest that intracellular ROS contribute, in part, to CM pathogenesis. Therapeutic targeting of intracellular ROS in CM is discussed.

Cerebral malaria in children: using the retina to study the brain

Cerebral malaria is a dangerous complication of Plasmodium falciparum infection, which takes a devastating toll on children in sub-Saharan Africa. Although autopsy studies have improved understanding of cerebral malaria pathology in fatal cases, information about in vivo neurovascular pathogenesis is scarce because brain tissue is inaccessible in life. Surrogate markers may provide insight into pathogenesis and thereby facilitate clinical studies with the ultimate aim of improving the treatment and prognosis of cerebral malaria. The retina is an attractive source of potential surrogate markers for paediatric cerebral malaria because, in this condition, the retina seems to sustain microvascular damage similar to that of the brain. In paediatric cerebral malaria a combination of retinal signs correlates, in fatal cases, with the severity of brain pathology, and has diagnostic and prognostic significance. Unlike the brain, the retina is accessible to high-resolution, non-invasive imaging. We aimed to determine the extent to which paediatric malarial retinopathy reflects cerebrovascular damage by reviewing the literature to compare retinal and cerebral manifestations of retinopathy-positive paediatric cerebral malaria. We then compared retina and brain in terms of anatomical and physiological features that could help to account for similarities and differences in vascular pathology. These comparisons address the question of whether it is biologically plausible to draw conclusions about unseen cerebral vascular pathogenesis from the visible retinal vasculature in retinopathy-positive paediatric cerebral malaria. Our work addresses an important cause of death and neurodisability in sub-Saharan Africa. We critically appraise evidence for associations between retina and brain neurovasculature in health and disease, and in the process we develop new hypotheses about why these vascular beds are susceptible to sequestration of parasitized erythrocytes.

Host matrix metalloproteinases in cerebral malaria: new kids on the block against blood-brain barrier integrity?

Cerebral malaria (CM) is a life-threatening complication of falciparum malaria, associated with high mortality rates, as well as neurological impairment in surviving patients. Despite disease severity, the etiology of CM remains elusive. Interestingly, although the Plasmodium parasite is sequestered in cerebral microvessels, it does not enter the brain parenchyma: so how does Plasmodium induce neuronal dysfunction? Several independent research groups have suggested a mechanism in which increased blood–brain barrier (BBB) permeability might allow toxic molecules from the parasite or the host to enter the brain. However, the reported severity of BBB damage in CM is variable depending on the model system, ranging from mild impairment to full BBB breakdown. Moreover, the factors responsible for increased BBB permeability are still unknown. Here we review the prevailing theories on CM pathophysiology and discuss new evidence from animal and human CM models implicating BBB damage. Finally, we will review the newly-described role of matrix metalloproteinases (MMPs) and BBB integrity. MMPs comprise a family of proteolytic enzymes involved in modulating inflammatory response, disrupting tight junctions, and degrading sub-endothelial basal lamina. As such, MMPs represent potential innovative drug targets for CM.

A novel chitosan based antimalarial drug delivery against Plasmodium berghei infection

Chitosan is a natural polysaccharide that has attracted significant scientific interest during the last two decades and chitosan based nanodrug delivery systems seem to be a hopeful and viable strategy for improving disease treatment. This study aims to evaluate the potency of the polymer based nanochloroquine in application for attenuation of Plasmodium berghei infection in Swiss mice and effectiveness against the parasite induced oxidative stress and deoxyribo nucleic acid (DNA) damage in lymphocytes. Nanoparticle was prepared by ionotropic gelation between chitosan and sodium tripolyphosphate. The chloroquine was treated by the actual drug content of effective nanochloroquine and the nanodrug was charged with its effective dose for fifteen days, after successive infection development in Swiss mice. Gimsa staining of thin smear and flow cytometry analysis was pursued to reveal the parasitemia. Different oxidative markers, inflammatory markers, antioxidant enzymes level and also lymphocytic deoxyribo nucleic acid damage study were performed. The present study reveals the potency of the nanodrug which has been found as more prospective than only chloroquine treatment to combat the parasite infection, oxidative stress as well as inflammation and DNA damage. From the study, we conclude this nanodrug may be applicable as potent therapeutic agent than only chloroquine.

Glutathione peroxidase contributes with heme oxygenase-1 to redox balance in mouse brain during the course of cerebral malaria

Oxidative stress has been attributed both a key pathogenic and rescuing role in cerebral malaria (CM). In a Plasmodium berghei ANKA murine model of CM, host redox signaling and functioning were examined during the course of neurological damage. Host antioxidant defenses were early altered at the transcriptional level indicated by the gradually diminished expression of superoxide dismutase-1 (sod-1), sod-2, sod-3 and catalase genes. During severe disease, this led to the dysfunctional activity of superoxide dismutase and catalase enzymes in damaged brain regions. Vitagene associated markers (heat shock protein 70 and thioredoxin-1) also showed a decaying expression pattern that paralleled reduced expression of the transcription factors Parkinson disease 7, Forkhead box O 3 and X-box binding protein 1 with a role in preserving brain redox status. However, the oxidative stress markers reactive oxygen/nitrogen species were not accumulated in the brains of CM mice and redox proteomics and immunohistochemistry failed to detect quantitative or qualitative differences in protein carbonylation. Thus, the loss of antioxidant capacity was compensated for in all cerebral regions by progressive upregulation of heme oxygenase-1, and in specific regions by early glutathione peroxidase-1 induction. This study shows for the first time a scenario of cooperative glutathione peroxidase and heme oxygenase-1 upregulation to suppress superoxide dismutase, catalase, heat shock protein-70 and thioredoxin-1 downregulation effects in experimental CM, counteracting oxidative damage and maintaining redox equilibrium. Our findings reconcile the apparent inconsistency between the lack of oxidative metabolite build up and reported protective effect of antioxidant therapy against CM.

Zinc, copper and C-reactive protein in children with severe Plasmodium falciparum malaria in an area of unstable malaria transmission in eastern Sudan

BACKGROUND

Few data exist on the role of trace element in the pathogenesis of severe malaria.

OBJECTIVES

The study was conducted at Kassala Hospital, eastern Sudan, to investigate the role of zinc, copper and C-reactive protein levels in children with severe Plasmodium falciparum malaria.

METHODS

Zinc, copper and C-reactive protein levels were measured in sera of three groups of children (35 in each arm): those with severe malaria, those with uncomplicated P. falciparum malaria and healthy controls.

RESULTS

Although the zinc levels were significantly lower, the levels of copper and C-reactive protein were significantly higher in patients with severe P. falciparum. There was a significant inverse correlation between zinc and C-reactive protein and significant positive correlation between copper and C-reactive protein.

CONCLUSION

The change in zinc and copper may play a role in pathogenesis of P. falciparum malaria.