Erythropoietin Levels Increase during Cerebral Malaria and Correlate with Heme, Interleukin-10 and Tumor Necrosis Factor-Alpha in India

Hormones in malaria infection: influence on disease severity, host physiology, and therapeutic opportunities

Human malaria, caused by Plasmodium parasites, is a fatal disease that disrupts the host's physiological balance and affects the neuroendocrine system. This review explores how malaria influences and is influenced by hormones. Malaria activates the Hypothalamus-Pituitary-Adrenal axis, leading to increased cortisol, aldosterone, and epinephrine. Cortisol, while reducing inflammation, aids parasite survival, whereas epinephrine helps manage hypoglycemia. The Hypothalamus-Pituitary-Gonad and Hypothalamus-Pituitary-Thyroid axes are also impacted, resulting in lower sex and thyroid hormone levels. Malaria disrupts the renin-angiotensin-aldosterone system (RAAS), causing higher angiotensin-II and aldosterone levels, contributing to edema, hyponatremia and hypertension. Malaria-induced anemia is exacerbated by increased hepcidin, which impairs iron absorption, reducing both iron availability for the parasite and red blood cell formation, despite elevated erythropoietin. Hypoglycemia is common due to decreased glucose production and hyperinsulinemia, although some cases show hyperglycemia due to stress hormones and inflammation. Hypocalcemia, and hypophosphatemia are associated with low Vitamin D3 and parathyroid hormone but high calcitonin. Hormones such as DHEA, melatonin, PTH, Vitamin D3, hepcidin, progesterone, and erythropoietin protects against malaria. Furthermore, synthetic analogs, receptor agonists and antagonists or mimics of hormones like DHEA, melatonin, serotonin, PTH, vitamin D3, estrogen, progesterone, angiotensin, and somatostatin are being explored as potential antimalarial treatments or adjunct therapies. Additionally, hormones like leptin and PCT are being studied as probable markers of malaria infection.

Serum anti-erythropoietin antibodies among pregnant women with Plasmodium falciparum malaria and anaemia: A case-control study in northern Ghana

BACKGROUND

Anaemia in pregnancy is common in underdeveloped countries, and malaria remains the predominant cause of the condition in Ghana. Anti-erythropoietin (anti-EPO) antibody production may be implicated in the pathogenesis of Plasmodium falciparum malaria-related anaemia in pregnancy. This study ascertained the prevalence of anti-EPO antibody production and evaluated the antibodies' relationship with Plasmodium falciparum malaria and malaria-related anaemia in pregnancy.

METHODS

This hospital-based case-control study recruited a total of 85 pregnant women (55 with Plasmodium falciparum malaria and 30 controls without malaria). Venous blood was taken from participants for thick and thin blood films for malaria parasite microscopy. Complete blood count (CBC) analyses were done using an automated haematology analyzer. Sandwich enzyme-linked immunosorbent assay (ELISA) was used to assess serum erythropoietin (EPO) levels and anti-EPO antibodies. Data were analyzed using IBM SPSS version 22.0.

RESULTS

Haemoglobin (p<0.001), RBC (p<0.001), HCT (p = 0.006) and platelet (p<0.001) were significantly lower among pregnant women infected with Plasmodium falciparum. Of the 85 participants, five (5.9%) had anti-EPO antibodies in their sera, and the prevalence of anti-EPO antibody production among the Plasmodium falciparum-infected pregnant women was 9.1%. Plasmodium falciparum-infected pregnant women with anti-EPO antibodies had lower Hb (p<0.001), RBC (p<0.001), and HCT (p<0.001), but higher EPO levels (p<0.001). Younger age (p = 0.013) and high parasite density (p = 0.004) were significantly associated with Plasmodium falciparum-related anti-EPO antibodies production in pregnancy. Also, younger age (p = 0.039) and anti-EPO antibody production (p = 0.012) related to the development of Plasmodium falciparum malaria anaemia in pregnancy.

CONCLUSION

The prevalence of anti-EPO antibodies among pregnant women with Plasmodium falciparum malaria was high. Plasmodium falciparum parasite density and younger age could stimulate the production of anti-EPO antibodies, and the antibodies may contribute to the development of malarial anaemia in pregnancy. Screening for anti-EPO antibodies should be considered in pregnant women with P. falciparum malaria.

Sinigrin in combination with artesunate provides protection against lethal murine malaria via falcipain-3 inhibition and immune modulation

Plant-derived antimalarials are indispensable for malaria treatment and a platform for new drugs. The present study explores sinigrin, for malaria using in vitro, in silico and in vivo strategies and the immune response generated after administration. The compound exhibited promising activity against chloroquine (CQ)-resistant (RKL-9) IC₅₀ 5.14 μg/mL and CQ-sensitive (3D7) IC₅₀ 5.47 μg/mL strains of P. falciparum and was safe in both in vitro (CC₅₀ > 640 μg/mL) and in vivo (LD₅₀ > 2 g/kg) toxicity studies. In addition, virtual screening showed hydrogen bonding, hydrophobic and van der Waals interactions with amino acid residues of 3BPM (falcipain-3). In vivo studies revealed promising antimalarial activity of sinigrin (200 mg/kg) with 87.44% chemo-suppression on day 5 and significantly (p < 0.0001) enhanced the mean survival time (21 ± 4.74 days) in contrast to the infected control (5.4 ± 1.14 days). In combination therapy, sinigrin (100 mg/kg and 200 mg/kg) augmented the efficacy of artesunate (AS 50 mg/kg) with 100% survival and no recrudescence. These observations are further corresponded and supported by DLC, NO production, cytokine analysis, biochemical and histopathological studies. Treatment with the combination resulted in a regulated interplay of immune cells and cytokines aiding in parasite clearance in addition to its specific inhibitory activity. We report the antimalarial activity of sinigrin first time with best D-score against falcipain-3. These findings highlight sinigrin as a HIT molecule, which may potentially be used in drug and vaccine development approaches.

The Rough Guide to Monocytes in Malaria Infection

While half of the world's population is at risk of malaria, the most vulnerable are still children under five, pregnant women and returning travelers. Anopheles mosquitoes transmit malaria parasites to the human host; but how Plasmodium interact with the innate immune system remains largely unexplored. The most recent advances prove that monocytes are a key component to control parasite burden and to protect host from disease. Monocytes' protective roles include phagocytosis, cytokine production and antigen presentation. However, monocytes can be involved in pathogenesis and drive inflammation and sequestration of infected red blood cells in organs such as the brain, placenta or lungs by secreting cytokines that upregulate expression of endothelial adhesion receptors. Plasmodium DNA, hemozoin or extracellular vesicles can impair the function of monocytes. With time, reinfections with Plasmodium change the relative proportion of monocyte subsets and their physical properties. These changes relate to clinical outcomes and might constitute informative biomarkers of immunity. More importantly, at the molecular level, transcriptional, metabolic or epigenetic changes can “prime” monocytes to alter their responses in future encounters with Plasmodium. This mechanism, known as trained immunity, challenges the traditional view of monocytes as a component of the immune system that lacks memory. Overall, this rough guide serves as an update reviewing the advances made during the past 5 years on understanding the role of monocytes in innate immunity to malaria.

Antitumor Effects and Mechanism of n-butanol Fraction from Aril of Torreya grandis in H22 Mice

BACKGROUND

To determine the antitumor effects and its mechanism of n-butanol fraction from aril of Torreya grandis (BFAT) on H22 mice models of liver cancer.

MATERIALS AND METHODS

Sixty ICR male mice were used to establish H22 mice models of liver cancer and then randomly divided into six groups, the normal control group, the model control group, the positive group (cyclophosphamide [CTX]), the BFAT-treated group (high, 4 g/kg, medium, 2 g/kg, and low, 1 g/kg). The animals were sacrificed 15 days after oral administration, and tumors were taken out for the tumor weights and antitumor rates, while thymus and spleen were taken for thymus index and spleen index. Blood in eyeball was collected for the determination of aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin (Alb), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase enzyme (GSH-Px), tumor necrosis factor-α (TNF-α), interleukin-2 (IL-2), transforming growth factor-β1 (TGF-β1), and IL-10 in serum. Sections of tumor tissue were prepared, and morphological changes in tumor tissue cells were observed using hematoxylin and eosin staining technique.

RESULTS

Compared with the model control group, the tumor inhibition rate of the high-dose administered group is 60.15%, which is quite closed to the effect of CTX. Moreover, the tumor weight is decreased, the indexes of spleen, thymus were increased significantly. Furthermore, the administration of BFAT significantly enhanced the activities of TNF-α, IL-2, SOD, and GSH-Px and reduced the levels of AST, ALT, MDA, Alb, TGF-β1, and IL-10 (P < 0.01).

CONCLUSIONS

The results demonstrated that n-butanol fraction from aril of T. grandis showed out antitumor activity without obviously liver damage through potentiating immunologic function and antioxidant activity of tumor-bearing mice and which may become one potential as anticancer drug alternatives or supplements.

SUMMARY

High and medium groups could significant elevate the thymus and spleen indexes and the interleukin-2 and tumor necrosis factor-α level in serum of H22 micen-butanol fraction from aril of Torreya grandis (BFAT) could ameliorate the levels of aspartate aminotransferase, alanine aminotransferase and albumin to almost normal, and increase the concentrations of superoxide dismutase and glutathione peroxidase enzyme, decrease the malondialdehyde level in serum of mice significantlyBFAT may indirectly play the role of antitumor activity through improving immunologic functionBFAT had potent antitumor properties without obviously liver damage. Abbreviations used: DDP: Cisplatin; CTX: Cyclophosphamide; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; Alb: Albumin; MDA: Malondialdehyde; SOD: Superoxide dismutase; GSH-Px: Glutathione peroxide enzyme; TNF-α: Tumor necrosis factor-α; IL-2: Interleukin-2; TGF-β1: Transforming growth factor-β1; IL-10: Interleukin-10; HE: Hematoxylin and eosin; PBS: Phosphate-buffered saline; PFAT: Petroleum ether fraction from aril of Torreya grandis; EFAT: Ethyl acetate fraction from aril of Torreya grandis; BFAT: N-butanol fraction from aril of Torreya grandis.

Artesunate and erythropoietin synergistically improve the outcome of experimental cerebral malaria

Cerebral malaria (CM) is a severe neurological syndrome in humans and the main fatal cause of malaria. In malaria epidemic regions, despite appropriate anti-malarial treatment, 10-20% of deaths still occur during the acute phase. This is largely attributable to poor treatment access, therapeutic complexity and drug resistance; thus, developing additional clinical adjunctive therapies is an urgent necessity. In this study, we investigated the effect of artesunate (AST) and recombinant human erythropoietin (rhEPO) using an experimental cerebral malaria (ECM) model-C57BL/6 mice infected with Plasmodium berghei ANKA (PbA). Treatment with the combination of AST and rhEPO reduced endothelial activation and improved the integrity of blood brain barrier, which led to increased survival rate and reduced pathology in the ECM. In addition, this combination treatment down-regulated the Th1 response during PbA infection, which was correlated with the reduction of CCL2, TNF-α, IFN-γ, IL-12, IL-18, CXCL9 and CXCL10 levels, leading to reduced accumulation of pathogenic T cells in the brain. Meanwhile, AST and rhEPO combination led to decreased maturation and activation of splenic dendritic cells, expansion of regulatory T cells, and increased IL-10 and TGF-β production. In conclusion, these data provide a theoretical basis for clinical adjunct therapy with rhEPO and AST in human cerebral malaria patients.