In all organisms, the biotransformation of xenobiotics to less toxic and more hydrophilic compounds represents an effective defense strategy. In pathogens, the biotransformation of drugs (used for their elimination from the host) may provide undesirable protective effects that could potentially compromise the drug's efficacy. Accordingly, increased drug deactivation via accelerated biotransformation is now considered as one of the mechanisms of drug resistance. The present study summarizes the current knowledge regarding the biotransformation of anthelmintics, specifically drugs used to treat mainly nematodes, a group of parasites that are a significant health concern for humans and animals. The main biotransformation enzymes are introduced and their roles in anthelmintics metabolism in nematodes are discussed with a particular focus on their potential participation in drug resistance. Similarly, the inducibility of biotransformation enzymes with sublethal doses of anthelmintics is presented in view of its potential contribution to drug resistance development. In the conclusion, the main tasks awaiting scientists in this area are outlined.

• MeSH
• anthelmintika * farmakologie   metabolismus   farmakokinetika   MeSH
• biotransformace MeSH
• hlístice * účinky léků   metabolismus   enzymologie   MeSH
• léková rezistence * MeSH
• lidé MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• anthelmintika * MeSH

Aldo-keto reductases (AKRs), a superfamily of NADP(H)-dependent oxidoreductases, catalyze the oxidoreduction of a wide variety of eobiotic and xenobiotic aldehydes and ketones. In mammals, AKRs play essential roles in hormone and xenobiotic metabolism, oxidative stress, and drug resistance, but little is known about these enzymes in the parasitic nematode Haemonchus contortus. In the present study, 22 AKR genes existing in the H. contortus genome were investigated and a phylogenetic analysis with comparison to AKRs in Caenorhabditis elegans, sheep and humans was conducted. The constitutive transcription levels of all AKRs were measured in eggs, larvae, and adults of H. contortus, and their expression was compared in a drug-sensitive strain (ISE) and a benzimidazole-resistant strain (IRE) previously derived from the sensitive strain by imposing benzimidazole selection pressure. In addition, the inducibility of AKRs by exposure of H. contortus adults to benzimidazole anthelmintic flubendazole in vitro was tested. Phylogenetic analysis demonstrated that the majority of AKR genes in H. contortus lack orthologues in the sheep genome, which is a favorable finding for considering AKRs as potential drug targets. Large differences in the expression levels of individual AKRs were observed, with AKR1, AKR3, AKR8, and AKR10 being the most highly expressed at most developmental stages. Significant changes in the expression of AKRs during the life cycle and pronounced sex differences were found. Comparing the IRE and ISE strains, three AKRs were upregulated, and seven AKRs were downregulated in adults. In addition, the expression of three AKRs was induced by flubendazole exposure in adults of the ISE strain. Based on these results, AKR1, AKR2, AKR3, AKR5, AKR10 and AKR19 in particular merit further investigation and functional characterization with respect to their potential involvement in drug biotransformation and anthelmintic resistance in H. contortus.

• Klíčová slova
• AKR, Drug-resistance, Drug-susceptibility, Expression profile, Haemonchus contortus, Phylogenetic analysis,
• MeSH
• aldehydreduktasa genetika   metabolismus   MeSH
• aldo-keto reduktasy * genetika   metabolismus   MeSH
• anthelmintika farmakologie   MeSH
• benzimidazoly farmakologie   MeSH
• Caenorhabditis elegans genetika   účinky léků   enzymologie   MeSH
• fylogeneze * MeSH
• Haemonchus * genetika   účinky léků   enzymologie   MeSH
• léková rezistence genetika   MeSH
• lidé MeSH
• mebendazol * farmakologie   analogy a deriváty   MeSH
• ovce MeSH
• transkriptom MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aldehydreduktasa MeSH
• aldo-keto reduktasy * MeSH
• anthelmintika MeSH
• benzimidazoly MeSH
• flubendazole MeSH Prohlížeč
• mebendazol * MeSH

Carbonyl-reducing enzymes (CREs) catalyse the reduction of carbonyl groups in many eobiotic and xenobiotic compounds in all organisms, including helminths. Previous studies have shown the important roles of CREs in the deactivation of several anthelmintic drugs (e.g., flubendazole and mebendazole) in adults infected with the parasitic nematode Haemonchus contortus, in which the activity of a CRE is increased in drug-resistant strains. The aim of the present study was to compare the abilities of nematodes of both a drug-susceptible strain (ISE) and a drug-resistant strain (IRE) to reduce the carbonyl group of flubendazole (FLU) in different developmental stages (eggs, L1/2 larvae, L3 larvae, and adults). In addition, the effects of selected CRE inhibitors (e.g., glycyrrhetinic acid, naringenin, silybin, luteolin, glyceraldehyde, and menadione) on the reduction of FLU were evaluated in vitro and ex vivo in H. contortus adults. The results showed that FLU was reduced by H. contortus in all developmental stages, with adult IRE females being the most metabolically active. Larvae (L1/2 and L3) and adult females of the IRE strain reduced FLU more effectively than those of the ISE strain. Data from the in vitro inhibition study (performed with cytosolic-like fractions of H. contortus adult homogenate) revealed that glycyrrhetinic acid, naringenin, mebendazole and menadione are effective inhibitors of FLU reduction. Ex vivo study data showed that menadione inhibited FLU reduction and also decreased the viability of H. contortus adults to a similar extent. Naringenin and mebendazole were not toxic at the concentrations tested, but they did not inhibit the reduction of FLU in adult worms ex vivo.

• Klíčová slova
• Anthelmintics, Strongyloides, drug biotransformation, helminths, inhibitors,
• MeSH
• anthelmintika * farmakologie   terapeutické užití   MeSH
• Haemonchus * MeSH
• kyselina glycyrhetinová * farmakologie   MeSH
• larva MeSH
• mebendazol farmakologie   terapeutické užití   MeSH
• vitamin K 3 farmakologie   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• anthelmintika * MeSH
• flubendazole MeSH Prohlížeč
• kyselina glycyrhetinová * MeSH
• mebendazol MeSH
• vitamin K 3 MeSH

Albendazole (ABZ) is an anthelmintic frequently used to treat haemonchosis, a common parasitosis of ruminants caused by the gastrointestinal nematode Haemonchus contortus. This parasite is able to protect itself against ABZ via the formation of inactive ABZ-glycosides. The present study was designed to deepen the knowledge about the role of UDP-glycosyltransferases (UGTs) in ABZ glycosylation in H. contortus. The induction effect of phenobarbital, a classical inducer of UGTs, as well as ABZ and ABZ-sulphoxide (ABZSO, the main active metabolite of ABZ) on UGTs expression and UGT activity toward ABZ was studied ex vivo in isolated adult nematodes. The effect of three potential UGT inhibitors (5-nitrouracil, 4,6-dihydroxy-5-nitropyrimidine and sulfinpyrazone) on ABZ glycosylation was tested. Pre-incubation of nematodes with ABZ and ABZSO led to increased expression of several UGTs as well as ABZ-glycosides formation in subsequent treatment. Phenobarbital also induced UGTs expression, but did not affect ABZ biotransformation. In the nematode's subcellular fraction, sulfinpyrazone inhibited UGT activity toward ABZ, although no effect of other inhibitors was observed. The inhibitory potential of sulfinpyrazone on the formation of ABZ-glycosides was also proved ex vivo in living nematodes. The obtained results confirmed the role of UGTs in ABZ biotransformation in H. contortus adults and revealed sulfinpyrazone as a potent inhibitor of ABZ glycosylation in this parasite. The possible use of sulfinpyrazone with ABZ in combination therapy merits further research.

• Klíčová slova
• Anthelmintic resistance, Anthelmintics biotransformation, Benzimidazoles, Detoxification, Gene expression, Glycosylated metabolites, Glycosylation, Nematodes, UGT inhibitors, UHPLC-MS/MS,
• MeSH
• albendazol MeSH
• anthelmintika * terapeutické užití   MeSH
• fenobarbital metabolismus   farmakologie   terapeutické užití   MeSH
• glykosidy metabolismus   farmakologie   terapeutické užití   MeSH
• glykosyltransferasy MeSH
• Haemonchus * MeSH
• hlístice * MeSH
• nemoci ovcí * farmakoterapie   MeSH
• ovce MeSH
• sulfinpyrazon metabolismus   farmakologie   terapeutické užití   MeSH
• uridindifosfát MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• albendazol MeSH
• anthelmintika * MeSH
• fenobarbital MeSH
• glykosidy MeSH
• glykosyltransferasy MeSH
• sulfinpyrazon MeSH
• uridindifosfát MeSH

The efficacy of anthelmintic therapy of farm animals rapidly decreases due to drug resistance development in helminths. In resistant isolates, the increased expression and activity of drug-metabolizing enzymes (DMEs), e.g. cytochromes P450 (CYPs), UDP-glycosyltransferases (UGTs) and P-glycoprotein transporters (P-gps), in comparison to sensitive isolates have been described. However, the mechanisms and circumstances of DMEs induction are not well known. Therefore, the present study was designed to find the changes in expression of CYPs, UGTs and P-gps in adult parasitic nematodes Haemonchus contortus exposed to sub-lethal doses of the benzimidazole anthelmintic drug albendazole (ABZ) and its active metabolite ABZ-sulfoxide (ABZSO). In addition, the effect of ABZ at sub-lethal doses on the ability to deactivate ABZ during consequent treatment was studied. The results showed that contact of H. contortus adults with sub-lethal doses of ABZ and ABZSO led to a significant induction of several DMEs, particularly cyp-2, cyp-3, cyp-6, cyp-7, cyp-8, UGT10B1, UGT24C1, UGT26A2, UGT365A1, UGT366C1, UGT368B2, UGT367A1, UGT371A1, UGT372A1 and pgp-3, pgp-9.1, pgp-9.2, pgp-10. This induction led to increased formation of ABZ metabolites (especially glycosides) and their increased export from the helminths' body into the medium. The present study demonstrates for the first time that contact of H. contortus with sub-lethal doses of ABZ (e.g. during underdose treatment) improves the ability of H. contortus adults to deactivate ABZ in consequent therapy.

• Klíčová slova
• ABC-transporters, P-glycoprotein, UDP-glycosyl transferases, anthelmintics, benzimidazoles, cytochromes P450, drug resistance, nematode,
• MeSH
• albendazol analogy a deriváty   farmakologie   MeSH
• antinematodní látky farmakologie   MeSH
• Haemonchus účinky léků   enzymologie   MeSH
• léková rezistence * MeSH
• metabolická inaktivace MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• albendazol MeSH
• albendazole sulfoxide MeSH Prohlížeč
• antinematodní látky MeSH

UDP-glycosyltransferases (UGT), catalysing conjugation of UDP-activated sugar donors to small lipophilic chemicals, are widespread in living organisms from bacteria to fungi, plant, or animals. The progress of genome sequencing has enabled an assessment of the UGT multigene family in Haemonchus contortus (family Trichostrongylidae, Nematoda), a hematophagous gastrointestinal parasite of small ruminants. Here we report 32 putative UGT genes divided into 15 UGT families. Phylogenetic analysis in comparison with UGTs from Caenorhabditis elegans, a free-living model nematode, revealed several single member homologues, a lack of the dramatic gene expansion seen in C. elegans, but also several families (UGT365, UGT366, UGT368) expanded in H. contortus only. The assessment of constitutive UGT mRNA expression in H. contortus adults identified significant differences between females and males. In addition, we compared the expression of selected UGTs in the drug-sensitive ISE strain to two benzimidazole-resistant strains, IRE and WR, with different genetic backgrounds. Constitutive expression of UGT368B2 was significantly higher in both resistant strains than in the sensitive strain. As resistant strains were able to deactivate benzimidazole anthelmintics via glycosylation more effectively then the sensitive strain, UGT368B2 enhanced constitutive expression might contribute to drug resistance in H. contortus.

• Klíčová slova
• Detoxification, Haemonchus contortus, Resistance, UDP-glycosyltransferase,
• MeSH
• anthelmintika farmakologie   MeSH
• benzimidazoly farmakologie   MeSH
• Caenorhabditis elegans enzymologie   genetika   MeSH
• exprese genu MeSH
• fylogeneze * MeSH
• glykosylace MeSH
• glykosyltransferasy chemie   klasifikace   genetika   MeSH
• Haemonchus účinky léků   enzymologie   genetika   MeSH
• léková rezistence genetika   MeSH
• mapování chromozomů MeSH
• multigenová rodina MeSH
• nemoci ovcí parazitologie   MeSH
• ovce MeSH
• sexuální faktory MeSH
• uridindifosfát genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• anthelmintika MeSH
• benzimidazole MeSH Prohlížeč
• benzimidazoly MeSH
• glykosyltransferasy MeSH
• uridindifosfát MeSH

Haemonchus contortus (family Trichostrongylidae, Nematoda), a hematophagous gastrointestinal parasite found in small ruminants, has a great ability to develop resistance to anthelmintic drugs. We studied the biotransformation of the three benzimidazole anthelmintics: albendazole (ABZ), ricobendazole (albendazole S-oxide; RCB) and flubendazole (FLU) in females and males of H. contortus in both a susceptible ISE strain and resistant IRE strain. The ex vivo cultivation of living nematodes in culture medium with or without the anthelmintics was used. Ultrasensitive UHPLC/MS/MS analysis revealed 9, 7 and 12 metabolites of ABZ, RCB and FLU, respectively, with most of these metabolites now described in the present study for the first time in H. contortus. The structure of certain metabolites shows the presence of biotransformation reactions not previously reported in nematodes. There were significant qualitative and semi-quantitative differences in the metabolites formed by male and female worms. In most cases, females metabolized drugs more extensively than males. Adults of the IRE strain were able to form many more metabolites of all the drugs than adults of the ISE strain. Some metabolites were even found only in adults of the IRE strain. These findings suggest that increased drug metabolism may play a role in resistance to benzimidazole drugs in H. contortus.

• Klíčová slova
• Anthelmintics, Benzimidazole, Drug metabolism, Drug resistance, Nematode,
• MeSH
• albendazol analogy a deriváty   metabolismus   farmakologie   MeSH
• anthelmintika metabolismus   farmakologie   MeSH
• biochemické jevy MeSH
• biotransformace MeSH
• Haemonchus metabolismus   MeSH
• hemonchóza farmakoterapie   parazitologie   veterinární   MeSH
• léková rezistence * MeSH
• mebendazol analogy a deriváty   metabolismus   farmakologie   MeSH
• nemoci ovcí farmakoterapie   parazitologie   MeSH
• ovce parazitologie   MeSH
• sexuální faktory MeSH
• tandemová hmotnostní spektrometrie MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• albendazol MeSH
• albendazole sulfoxide MeSH Prohlížeč
• anthelmintika MeSH
• flubendazole MeSH Prohlížeč
• mebendazol MeSH