Nitric Oxide Pathophysiology in Malaria

Malaria imposes a profound burden on global health, and disturbances in nitric oxide (NO) bioavailability are central to its pathophysiology. NO, a key vasodilator and immune modulator, is generated by nitric oxide synthase (NOS) from l-arginine. In malaria, widespread endothelial activation, oxidative stress and elevated levels of arginase conspire to deplete l-arginine, yielding hypoargininaemia and reduced NO production. The ensuing vasoconstriction and microvascular obstruction exacerbate tissue hypoxia, contributing to severe complications such as cerebral malaria and acute organ dysfunction. Concurrently, malaria-induced inflammatory signals can skew monocytes towards an M2-like phenotype, which further diminishes inducible NOS expression and sustains a cycle of NO insufficiency. Endothelial glycocalyx degradation in infected vessels undermines mechanotransduction of shear stress to NOS, limiting NO release and impairing microcirculatory flow. At the red cell level, diminished NO impairs erythrocyte deformability, exacerbating sequestration in the microvasculature. Collectively, these alterations underscore NO’s dual role in vascular regulation and host defence. Understanding the biochemical and cellular checkpoints governing NO production has informed novel adjunctive strategies aimed at restoring NO bioavailability and alleviating microvascular dysfunction in severe malaria.

Research from Nature Portfolio

Recent investigations have illuminated the contribution of host immune phenotype shifts to NO dynamics in falciparum malaria. Studies in paediatric cohorts revealed that M2-polarised monocytes, marked by elevated arginase-1 activity and anti-inflammatory cytokines, correlate with low plasma l-arginine and impaired NO synthesis, heightening disease severity. Parallel work in adults has employed targeted metabolomics to quantify plasma free amino acids, demonstrating that global reductions in l-arginine and other amino acids align with markers of endothelial dysfunction and metabolic acidosis. These analyses have delineated patterns of amino acid derangement that predict microvascular impairment and clinical outcomes, reinforcing the central role of hypoargininaemia in NO bioavailability and vascular pathology.

Nitric Oxide Pathophysiology in Malaria publication trend

The graph below shows the total number of articles in nitric oxide pathophysiology in malaria across all publications each year (not limited to Nature Index journals).

Technical terms

Nitric Oxide (NO): A gaseous signalling molecule produced by nitric oxide synthase that mediates vasodilation, inhibits parasite adhesion and modulates immune responses.

Hypoargininaemia: A pathological reduction in plasma l-arginine concentrations, limiting substrate availability for NO synthesis and promoting vascular dysfunction.

Endothelial Glycocalyx: A carbohydrate-rich layer lining blood vessel walls that regulates shear-stress sensing, vascular permeability and NO release.

Asymmetric Dimethylarginine (ADMA): An endogenous inhibitor of NOS derived from protein methylation, which competes with l-arginine and reduces NO production when elevated.

Monocyte M2 Polarisation: A macrophage-like activation state characterised by anti-inflammatory cytokine production and increased arginase activity that suppresses NO synthesis.

References

1. Association between Plasmodium Infection and Nitric Oxide Levels: A Systematic Review and Meta-Analysis. Antioxidants (2023).
2. Monocyte polarization in children with falciparum malaria: relationship to nitric oxide insufficiency and disease severity. Scientific Reports (2016).
3. Vascular Dysfunction in Malaria: Understanding the Role of the Endothelial Glycocalyx. Frontiers in Cell and Developmental Biology (2021).
4. Reduced erythrocyte deformability associated with hypoargininemia during Plasmodiumfalciparum malaria. Scientific Reports (2014).
5. Amino acid derangements in adults with severe falciparum malaria. Scientific Reports (2019).
6. Increased Asymmetric Dimethylarginine in Severe Falciparum Malaria: Association with Impaired Nitric Oxide Bioavailability and Fatal Outcome. PLOS Pathogens (2010).