Kinetic and Cross-Sectional Studies on the Genesis of Hypoargininemia in Severe Pediatric Plasmodium falciparum Malaria

dc.contributor.authorKalabamu, Florence S.
dc.contributor.authorKalingonji, Ayam R.
dc.contributor.authorMwaikambo, Esther D.
dc.date.accessioned2020-02-17T12:07:58Z
dc.date.available2020-02-17T12:07:58Z
dc.date.issued2019
dc.description.abstractThe low bioavailability of nitric oxide (NO) and its precursor, arginine, contributes to the microvascular pathophysiology of severe falciparum malaria. To better characterize the mechanisms underlying hypoargininemia in severe malaria, we measured the plasma concentrations of amino acids involved in de novo arginine synthesis in children with uncomplicated falciparum malaria (UM; n = 61), children with cerebral falciparum malaria (CM; n = 45), and healthy children (HC; n = 109). We also administered primed infusions of l-arginine uniformly labeled with 13C6 and 15N4 to 8 children with severe falciparum malaria (SM; age range, 4 to 9 years) and 7 healthy children (HC; age range, 4 to 8 years) to measure the metabolic flux of arginine, hypothesizing that arginine flux is increased in SM. Using two different tandem mass spectrometric methods, we measured the isotopic enrichment of arginine in plasma obtained at 0, 60, 90, 120, 150, and 180 min during the infusion. The plasma concentrations of glutamine, glutamate, proline, ornithine, citrulline, and arginine were significantly lower in UM and CM than in HC (P ≤ 0.04 for all pairwise comparisons). Of these, glutamine concentrations were the most markedly decreased: median, 457 μM (interquartile range [IQR], 400 to 508 μM) in HC, 300 μM (IQR, 256 to 365 μM) in UM, and 257 μM (IQR, 195 to 320 μM) in CM. Arginine flux during steady state was not significantly different in SM than in HC by the respective mass spectrometric methods: 93.2 μmol/h/kg of body weight (IQR, 84.4 to 129.3 μmol/h/kg) versus 88.0 μmol/h/kg (IQR, 73.0 to 102.2 μmol/h/kg) (P = 0.247) by the two mass spectrometric methods in SM and 93.7 μmol/h/kg (IQR, 79.1 to 117.8 μmol/h/kg) versus 81.0 μmol/h/kg (IQR, 75.9 to 88.6 μmol/h/kg) (P = 0.165) by the two mass spectrometric methods in HC. A limited supply of amino acid precursors for arginine synthesis likely contributes to the hypoargininemia and NO insufficiency in falciparum malaria in children.en_US
dc.identifier.citationRubach, M.P., Zhang, H., Florence, S.M., Mukemba, J.P., Kalingonji, A.R., Anstey, N.M., Yeo, T.W., Lopansri, B.K., Thompson, J.W., Mwaikambo, E.D. and Young, S., 2019. Kinetic and cross-sectional studies on the genesis of hypoargininemia in severe pediatric Plasmodium falciparum malaria. Infection and immunity, 87(4), pp.e00655-18.en_US
dc.identifier.otherDOI: 10.1128/IAI.00655-18
dc.identifier.urihttp://hdl.handle.net/123456789/236
dc.language.isoenen_US
dc.publisherInfection and immunityen_US
dc.subjectPlasmodium falciparumen_US
dc.subjectArginineen_US
dc.subjectGlutamineen_US
dc.subjectNitric Oxideen_US
dc.subjectMalariaen_US
dc.titleKinetic and Cross-Sectional Studies on the Genesis of Hypoargininemia in Severe Pediatric Plasmodium falciparum Malariaen_US
dc.typeArticleen_US

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