Spatial visualization of drug uptake and distribution in Fasciola hepatica using high-resolution AP-SMALDI mass spectrometry imaging

Abstract

Understanding drug penetration, distribution, and metabolization is fundamental for understanding drug efficacy. This also accounts for parasites during antiparasitic treatment. Recently, we established matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) in blood flukes and liver flukes. This label-free technique is capable of visualizing the molecular distribution of endogenous and exogenous molecules, such as drug compounds. Here, we conducted atmospheric-pressure scanning microprobe MALDI MSI (AP-SMALDI MSI) of tissue sections of adult Fasciola hepatica that have been treated in vitro with 100 µM of triclabendazole (TCBZ), the drug of choice for treatment of fasciolosis, and its main metabolite triclabendazole sulfoxide (TCBZ-SO). Measurements covered an m/z mass range of 250–1,000 and provided a high spatial resolution using a pixel size of 10 µm. To support the interpretation of drug distribution, we first identified endogenous lipids that mark characteristic tissues such as the gastrodermis, the tegument, and the parenchyma. The obtained results suggested an early tegumental route of TCBZ uptake within 20 min, followed by spreading throughout the parasite after 4 h, and an even distribution in most tissues after 12 h. This coincided with a strong reduction of parasite vitality. TCBZ-SO treatment demonstrated the accumulation of this metabolite in the same tissues as the parent drug compound. These data demonstrate the auspicious potential of MALDI MSI to visualize uptake and distribution patterns of drugs or drug-candidate compounds in parasites, which might contribute to preclinical drug discovery in liver fluke research and beyond.

Mass Spectrometry Imaging: An Emerging Technology in Medical Parasitology

“…In a subsequent study conducted by Morawietz et al in 2022, AP-SMALDI MSI was utilized to visualize the uptake patterns and molecular distribution of drug compounds in liver flukes. 73 The image analysis identified the spatial distribution of triclabendazole (TCBZ) and one of its major metabolites, triclabendazole sulfoxide (TCBZ-SO), within F. hepatica after exposure to pharmaceutical compounds for varying periods of time. Remarkably, lipid marker signals were also detected, which could be easily targeted within the parasite fraction, facilitating accurate assignment of even small amounts of accumulated drug signals.…”

MALDI Mass Spectrometry Imaging: A Potential Game-Changer in a Modern Microbiology

“…While developing and testing new drug molecules, researchers need to not only understand how they could be distributed or accumulated in pathogens or tissues, but also study the metabolization of the drug by the pathogen. In this sense, several research works were performed by MALDI-MSI applied to bacteria and parasites [ 70 , 102 , 103 ]. Morawietz and colleagues analyzed the spatial distribution of triclabendazole in the trematode Fasciola hepatica in order to identify the uptake route and tissue tropism of the drug [ 102 ].…”

“…In this sense, several research works were performed by MALDI-MSI applied to bacteria and parasites [ 70 , 102 , 103 ]. Morawietz and colleagues analyzed the spatial distribution of triclabendazole in the trematode Fasciola hepatica in order to identify the uptake route and tissue tropism of the drug [ 102 ].…”

“…Along the same line, current devices used in routine microbiology laboratories are working under vacuum settings with a single ionization laser source. Interestingly, several publications described in Table 1 are using atmospheric pressure (AP) MALDI-MSI, i.e., the ionization takes place under atmospheric conditions [ 89 , 99 , 101 , 102 , 103 , 104 , 106 ]. The advantage to operating ionization at AP for MSI analysis is the elimination of the pumping time, the ease of sample preparation and the analysis of volatile molecules.…”

“… Kinetic of triclabendazole (TCBZ) uptake and distribution in Fasciola hepatica . Figure was reproduced from Morawietz and colleagues’ work [ 102 ]. …”