Cytotoxicity and Functional Toxicity of Mefloquine and the Search for Protective Compounds

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Mefloquine hydrochloride is an antimalarial agent that has been used for the past 40 years. Numerous reports of neurological side effects have recently led the FDA to issue a strong warning regarding long-term neurological effects. This warning lead to the U.S. Army’s Special Forces and other components to discontinue its use in July of 2013. Despite reported adverse side effects, mefloquine remains in circulation and is recommended to travelers going to specific Asian countries. Mefloquine has been used as a treatment for those already infected with the malaria parasite (blood concentrations ranging from 2.1 to 23 µM), and as prophylaxis ... continued below

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iii, 43 pages : illustrations (some color)

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Holmes, Katelyn May 2015.

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This thesis is part of the collection entitled: UNT Theses and Dissertations and was provided by UNT Libraries to Digital Library, a digital repository hosted by the UNT Libraries. It has been viewed 32 times . More information about this thesis can be viewed below.

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  • Holmes, Katelyn

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Mefloquine hydrochloride is an antimalarial agent that has been used for the past 40 years. Numerous reports of neurological side effects have recently led the FDA to issue a strong warning regarding long-term neurological effects. This warning lead to the U.S. Army’s Special Forces and other components to discontinue its use in July of 2013. Despite reported adverse side effects, mefloquine remains in circulation and is recommended to travelers going to specific Asian countries. Mefloquine has been used as a treatment for those already infected with the malaria parasite (blood concentrations ranging from 2.1 to 23 µM), and as prophylaxis (blood concentrations averaging 3.8 µM) (Dow 2003). The purpose of this study was to quantify Mefloquine’s toxicity using spontaneously active nerve cell networks growing on microelectrode arrays in vitro and to identify compounds that alleviate or reduce toxic effects. The current literature on mefloquine toxicity is lacking electrophysiological data. These data will contribute to research on the mechanism of adverse side effects associated with mefloquine use. Sequential titration experiments were performed by adding increasing concentrations of mefloquine solution to cultured neurons. Network responses were quantified and reversibility was examined. In each network, activity decreases were normalized as a percent of reference activity yielding a mean IC50 value of 5.97 ± 0.44 (SD) µM (n=6). After total activity loss, no activity was recovered with two successive medium changes. To test for network response desensitization resulting from sequential applications over 5-6 hr periods, one-point titrations at varying concentrations were conducted with fresh networks. These experiments yielded a single concentration response curve with an IC50 value of 2.97 µM. This represents a statistically significant shift (p < 0.0001) to lower concentrations of mefloquine, demonstrating that sequential applications result in network desensitization. After mefloquine exposures, cells were evaluated for irreversible cytotoxic damage. Over a 12-hour period under 6 µM mefloquine, process beading and granulation of somal cytoplasm were observed. At 8 µM mefloquine cell stress was apparent after only 10 minutes with major glial damage and process beading at 120 minutes. In this study, quinolinic acid served as a neuroprotectant at 20 µM. There have been multiple studies on the endogenous concentrations of quinolinic acid and current literature is quite variable. Immunocompromised individuals have some of the highest blood levels of quinolinic acid (up to 20 µM). With 30 min pre-applications of quinolinic acid, the mefloquine IC50 value shifted from 5.97 ± 0.44 µM (n=6), to 9.28 ± 0.55 µM (n=3). This represents a statistically significant change to higher mefloquine concentrations and demonstrates neuroprotection.

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iii, 43 pages : illustrations (some color)

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UNT Theses and Dissertations

Theses and dissertations represent a wealth of scholarly and artistic content created by masters and doctoral students in the degree-seeking process. Some ETDs in this collection are restricted to use by the UNT community.

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  • May 2015

Added to The UNT Digital Library

  • Feb. 9, 2016, 4:37 p.m.

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  • Feb. 20, 2017, 7:48 a.m.

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Holmes, Katelyn. Cytotoxicity and Functional Toxicity of Mefloquine and the Search for Protective Compounds, thesis, May 2015; Denton, Texas. (digital.library.unt.edu/ark:/67531/metadc801913/: accessed April 22, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .