Clinical Mass Spectrometry: the Assessment of Acidosis Profiles and Acute Kidney Injury in Severe Malaria Natthida Sriboonvorakul (Presenter) Mahidol University Presenter Bio: Dr. Natthida Sriboonvorakul is PhD lecturer in Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University. She has professional interest in Clinical Chemistry research using several advance technologies including analytical separation, chromatography and mass spectrometry. She had experience in clinical mass spectrometry study in malaria disease (Sriboonvorakul, Leepipatpiboon et al. 2013, Herdman, Sriboonvorakul et al. 2015) this research was collaboration with Mahidol Oxford Tropical Medicine research unit and recently, Sriboonvorakul, Ghose et al. 2018 published in Malaria Journal. In 2016, her research title "Clinical Mass Spectrometry: Introduction to kinetic study of acidosis in patients with severe malaria” received best poster award honorable mention in HPLC 2016 Symposium, United States of America.

Authors: Natthida Sriboonvorakul (1), Sasithon Pukrittayakamee (1), Kesinee Chotivanich (1), Yaowalark Sukthana (2), Stije J. Leopold (3,4), Katherine Plewes (3,4), Nicholas P. J. Day (3,4), Nicholas J. White (3,4), Joel Tarning (3,4) and Arjen M. Dondorp (3,4)*
(1) Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand (2) Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand (3) Mahidol‑Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand (4) Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.

In severe falciparum malaria acidosis and acute kidney injury (AKI) are independent predictors of a fatal outcome. The relationship between plasma acids, urine acids and renal function was investigated in adult patients with acute falciparum malaria. Clinical mass spectroscopy was utilized for assessment of small organic acid profiles. Plasma and urinary concentrations of selected acids were increased in falciparum malaria patients according to disease severity. Principal component analysis separated a group of patients with AKI and mainly driven by p-hydroxyphenyl lactate (pHPLA) concentrations in both plasma and urine. pHPLA could contribute to acute kidney injury in severe malaria.

Introduction:

In severe falciparum malaria acidosis and acute kidney injury (AKI) are independent predictors of a fatal outcome in all age groups.

The relationship between plasma acids, urine acids and renal function was investigated in adult patients with severe falciparum malaria. Clinical mass spectroscopy approach was developed, validated and utilized for quantification of eight possible small organic acids; l-lactic acid (LA), alpha-hydroxybutyric acid (aHBA), beta-hydroxybutyric acid (bHBA), p-hydroxyphenyllactic acid (pHPLA), malonic acid (MA), methylmalonic acid (MMA), ethylmalonic acid (EMA) and alpha-ketoglutaric acid (aKGA). These small organic acids were analyzed simultaneously and showed increased concentrations in proportion to disease severity.

Methods:

Hydrophilic interaction liquid chromatography (HILIC) coupled to negative mass spectroscopy was utilized for separation, detection and quantification of eight possible acids simultaneously. High-throughput strong anion exchange solid-phase extraction in a 96-well plate format was used for sample preparation. This developed method was validated according to U.S. Food and Drug Administration guidelines with additional validation procedures for endogenous substances. Plasma and urinary acids in patients with severe falciparum malaria (n=90) were quantified compare to in patients with uncomplicated malaria (n=94), sepsis (n=19) and healthy volunteers (n=61) served as comparator groups. Multiple regression and multivariate analysis were used to assess the relationship between organic acid concentrations and clinical syndromes, in particular AKI.

Results:

Accuracy for all eight acids ranged from 93.1% to 104.0%, and the within-day and between-day precisions (i.e. relative standard deviations) were lower than 5.5% at all tested concentrations. Univariate analysis showed that both plasma and creatinine-adjusted urine concentrations of p-hydroxyphenyllactic acid (pHPLA) were higher in severe malaria patients with AKI (p < 0.001). Multiple regression analysis, including plasma or creatinine-adjusted urinary acids, and PfHRP2 as parasite biomass marker as independent variables, showed that pHPLA was independently associated with plasma creatinine (β = 0.827) and urine creatinine (β = 0.226).

Principal component analysis, including four plasma acids and seven urinary acids separated a group of patients with AKI, which was mainly driven by pHPLA concentrations.

Conclusions & Discussion:

Both plasma and urine concentrations of pHPLA closely correlate with AKI in patients with severe falciparum malaria. Further studies will need to assess the potential nephrotoxic properties of pHPLA.

1. Sriboonvorakul N, Ghose A, Hassan MMU, Hossain MA, Faiz MA, Pukrittayakamee S, Chotivanich K, Sukthana Y, Leopold SJ, Plewes K, et al: Acidosis and acute kidney injury in severe malaria. Malaria Journal 2018, 17:128.

2. Sriboonvorakul N, Leepipatpiboon N, Dondorp AM, Pouplin T, White NJ, Tarning J, Lindegardh N: Liquid chromatographic-mass spectrometric method for simultaneous determination of small organic acids potentially contributing to acidosis in severe malaria. J Chromatogr B Analyt Technol Biomed Life Sci 2013, 941:116-122.

3. Herdman MT, Sriboonvorakul N, Leopold SJ, Douthwaite S, Mohanty S, Hassan MM, Maude RJ, Kingston HW, Plewes K, Charunwatthana P, et al: The role of previously unmeasured organic acids in the pathogenesis of severe malaria. Crit Care 2015, 19:317.