scholarly journals Uptake of the antitrypanosomal drug 5′-{[(Z)-4-amino-2-butenyl]methylamino}-5′-deoxyadenosine (MDL 73811) by the purine transport system of Trypanosoma brucei brucei

1992 ◽  
Vol 283 (3) ◽  
pp. 755-758 ◽  
Author(s):  
T L Byers ◽  
P Casara ◽  
A J Bitonti
Keyword(s):  
Trypanosoma Brucei ◽  
Transport System ◽  
Time Course ◽  
Multidrug Resistant ◽  
Trypanosoma Brucei Brucei ◽  
Irreversible Inhibitor ◽  
Highly Active ◽  
Mouse Leukaemia

An irreversible inhibitor of S-adenosyl-L-methionine decarboxylase (AdoMetDC), 5′-([(Z)-4-amino-2-butenyl]methylamino)-5′-deoxyadenosine (MDL 73811), was found to cure Trypanosoma brucei brucei and multidrug-resistant T. b. rhodesiense infections in mice [Bitonti, Byers, Bush, Casara, Bacchi, Clarkson, McCann & Sjoerdsma (1990) Antimicrob. Agents Chemother. 34, 1485-1490]. Doses of this drug which resulted in a rapid clearance of parasites from T. b. brucei-infected rats resulted in plasma levels of 50-60 microM-MDL 73811 and an intratrypanosomal MDL 73811 concentration of 1.9 mM within 10 min of administration [Byers, Bush, McCann & Bitonti (1991) Biochem. J. 274, 527-533[. Based on this finding we speculated that MDL 73811, which is an adenosine analogue, is a substrate for the trypanosome active purine transport system. We now report evidence that supports this hypothesis. MDL 73811 uptake by T. b. brucei in vitro was time- and temperature-dependent and was saturable over a time course in which MDL 73811 metabolism was undetectable, suggesting that MDL 73811 uptake is a transport-mediated phenomenon. Inhibition of MDL 73811 uptake by purine nucleosides is consistent with the drug being a substrate for the trypanosome purine transport system. The accumulation of MDL 73811 by cultured L1210 mouse leukaemia cells was significantly less than by trypanosomes exposed to the same pharmacologically relevant concentrations of MDL 73811. Given that the half-life of MDL 73811 in the plasma of rats and mice is approx. 10 min, it seems likely that the existence of a highly active parasite transport system for MDL 73811 is crucial for the sensitivity of trypanosomes towards MDL 73811 in vivo, and that the absence of active transport of MDL 73811 by the host's cells may play a role in the selectivity of this drug.

scholarly journals Cross-Resistance to Nitro Drugs and Implications for Treatment of Human African Trypanosomiasis

2010 ◽  
Vol 54 (7) ◽  
pp. 2893-2900 ◽  
Author(s):  
Antoaneta Y. Sokolova ◽  
Susan Wyllie ◽  
Stephen Patterson ◽  
Sandra L. Oza ◽  
Kevin D. Read ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Human African Trypanosomiasis ◽  
Parent Drug ◽  
Cross Resistance ◽  
Pharmacokinetic Studies ◽  
African Trypanosomiasis ◽  
Trypanosoma Brucei Brucei ◽  
Resistant Lines

ABSTRACT The success of nifurtimox-eflornithine combination therapy (NECT) for the treatment of human African trypanosomiasis (HAT) has renewed interest in the potential of nitro drugs as chemotherapeutics. In order to study the implications of the more widespread use of nitro drugs against these parasites, we examined the in vivo and in vitro resistance potentials of nifurtimox and fexinidazole and its metabolites. Following selection in vitro by exposure to increasing concentrations of nifurtimox, Trypanosoma brucei brucei nifurtimox-resistant clones designated NfxR1 and NfxR2 were generated. Both cell lines were found to be 8-fold less sensitive to nifurtimox than parental cells and demonstrated cross-resistance to a number of other nitro drugs, most notably the clinical trial candidate fexinidazole (∼27-fold more resistant than parental cells). Studies of mice confirmed that the generation of nifurtimox resistance in these parasites did not compromise virulence, and NfxR1 remained resistant to both nifurtimox and fexinidazole in vivo. In the case of fexinidazole, drug metabolism and pharmacokinetic studies indicate that the parent drug is rapidly metabolized to the sulfoxide and sulfone form of this compound. These metabolites retained trypanocidal activity but were less effective in nifurtimox-resistant lines. Significantly, trypanosomes selected for resistance to fexinidazole were 10-fold more resistant to nifurtimox than parental cells. This reciprocal cross-resistance has important implications for the therapeutic use of nifurtimox in a clinical setting and highlights a potential danger in the use of fexinidazole as a monotherapy.

scholarly journals JPC-2997, a New Aminomethylphenol with HighIn VitroandIn VivoAntimalarial Activities against Blood Stages of Plasmodium

2014 ◽  
Vol 59 (1) ◽  
pp. 170-177 ◽  
Author(s):  
Geoffrey W. Birrell ◽  
Marina Chavchich ◽  
Arba L. Ager ◽  
Hong-Ming Shieh ◽  
Gavin D. Heffernan ◽  
...  
Keyword(s):  
Half Life ◽  
Multidrug Resistant ◽  
Volume Of Distribution ◽  
Parasite Line ◽  
Content Type ◽  
Elimination Half Life ◽  
Highly Active ◽  
Elimination Half

ABSTRACT4-(tert-Butyl)-2-((tert-butylamino)methyl)-6-(6-(trifluoromethyl)pyridin-3-yl)-phenol (JPC-2997) is a new aminomethylphenol compound that is highly activein vitroagainst the chloroquine-sensitive D6, the chloroquine-resistant W2, and the multidrug-resistant TM90-C2BPlasmodium falciparumlines, with 50% inhibitory concentrations (IC50s) ranging from 7 nM to 34 nM. JPC-2997 is >2,500 times less cytotoxic (IC50s > 35 μM) to human (HepG2 and HEK293) and rodent (BHK) cell lines than the D6 parasite line. In comparison to the chemically related WR-194,965, a drug that had advanced to clinical studies, JPC-2997 was 2-fold more activein vitroagainstP. falciparumlines and 3-fold less cytotoxic. The compound possesses potentin vivosuppression activity againstPlasmodium berghei, with a 50% effective dose (ED50) of 0.5 mg/kg of body weight/day following oral dosing in the Peters 4-day test. The radical curative dose of JPC-2997 was remarkably low, at a total dose of 24 mg/kg, using the modified Thompson test. JPC-2997 was effective in curing threeAotusmonkeys infected with a chloroquine- and pyrimethamine-resistant strain ofPlasmodium vivaxat a dose of 20 mg/kg daily for 3 days. At the doses administered, JPC-2997 appeared to be well tolerated in mice and monkeys. Preliminary studies of JPC-2997 in mice show linear pharmacokinetics over the range 2.5 to 40 mg/kg, a low clearance of 0.22 liters/h/kg, a volume of distribution of 15.6 liters/kg, and an elimination half-life of 49.8 h. The highin vivopotency data and lengthy elimination half-life of JPC-2997 suggest that it is worthy of further preclinical assessment as a partner drug.

scholarly journals In vitro and in vivo anti-trypanosomal potentials of Afrormosia laxiflora and Khaya senegalensis against Trypanosoma brucei brucei

2018 ◽  
Vol 39 (3) ◽  
pp. 269-284
Author(s):  
G.D. Chechet ◽  
J Yahaya ◽  
A.J. Nok
Keyword(s):  
Body Weight ◽  
Trypanosoma Brucei ◽  
Post Infection ◽  
Methanol Extract ◽  
Control Group ◽  
Phytochemical Analysis ◽  
Trypanosoma Brucei Brucei ◽  
Khaya Senegalensis

Animal African trypanosomiasis (AAT) also known as Nagana is a resurgent disease in Africa. Medicinal plants are being used in less developed countries for the treatment of various diseases including trypanosomiasis, due to the high cost of currently available drugs. Most of these plants have been useful sources of treatment of various diseases based on information obtained from folk medicine but have not been scientifically certified. Here, we investigated the in vitro and in vivo anti-trypanosomal potentials of the methanol extract of Aformorsia laxiflora and Khaya senegalensis against T. b. brucei. Phytochemical screening as well as LD50 of the plant extracts was carried out following standard procedures. Parasitemia was monitored daily while Packed Cell Volume was determined at three time points (days 1, 4 and 7) during the course of the infection. The phytochemical analysis showed the presence of saponins, alkaloids, flavonoids, antraquinones, resins and tanins. However, steriods/terpenoids were absent in K. senegalensis but present in A. laxiflora. The toxicity of methanol extract of both A. laxiflora and K. senegalensis was above 5000mg/kg body weight. Methanol extracts of A. laxiflora (leaves) and K. senegalensis (stem bark) showed promising trypanocidal potential in vitro against T. b. brucei at concentrations of 10, 15, 25mg/ml and 40 and 20mg/ml respectively. At these concentrations, both extracts immobilized the parasites within 55mins post-incubation. In general, A. laxiflora leaf extract demonstrated prophylactic activity against T. b. brucei in vivo at a dose of 500mg/Kg body weight particularly in group C animals where a delayed pre-patent period (6 days post-infection), extended survival (14 days post-infection) and significant (P<0.05) reduction in the parasite burden confirmed by an absence of anemia (PCV 47.00±0.8 %) was observed when compared to the infected untreated control group. K. senegalensis extract on the other hand did not show anti-trypanosomal activity in the treated groups (1, 2, and 3). Based on these observations, it was therefore deduced that the methanol extract of leaves of A. laxiflora possessed the ability to ameliorate the burden of the disease and could be a plausible candidate for drug development against the disease.Keywords: Trypanosoma brucei brucei, Afromosia laxiflora, Khaya senegalensis, anti-trypanosomal, in vitro, in vivo

scholarly journals Novel 4-Aminoquinoline Analogs Highly Active against the Blood and Sexual Stages of PlasmodiumIn VivoandIn Vitro

2012 ◽  
Vol 56 (9) ◽  
pp. 4685-4692 ◽  
Author(s):  
Fabián E. Sáenz ◽  
Tina Mutka ◽  
Kenneth Udenze ◽  
Ayoade M. J. Oduola ◽  
Dennis E. Kyle
Keyword(s):  
Plasmodium Berghei ◽  
Multidrug Resistant ◽  
New Drugs ◽  
Content Type ◽  
Highly Active ◽  
Resistant Strains ◽  
Sexual Stages ◽  
The 1960S

ABSTRACTNew drugs to treat malaria must act rapidly and be highly potent against asexual blood stages, well tolerated, and affordable to residents of regions of endemicity. This was the case with chloroquine (CQ), a 4-aminoquinoline drug used for the prevention and treatment of malaria. However, since the 1960s,Plasmodium falciparumresistance to this drug has spread globally, and more recently, emerging resistance to CQ byPlasmodium vivaxthreatens the health of 70 to 320 million people annually. Despite the emergence of CQ resistance, synthetic quinoline derivatives remain validated leads for new drug discovery, especially if they are effective against CQ-resistant strains of malaria. In this study, we investigated the activities of two novel 4-aminoquinoline derivatives, TDR 58845,N1-(7-chloro-quinolin-4-yl)-2-methyl-propane-1,2-diamine, and TDR 58846,N1-(7-chloro-quinolin-4-yl)-2,N2,N2-trimethylpropane-1,2-diamine and found them to be active againstP. falciparumin vitroandPlasmodium bergheiin vivo. TheP. falciparumclones and isolates tested were susceptible to TDR 58845 and TDR 58846 (50% inhibitory concentrations [IC50s] ranging from 5.52 to 89.8 nM), including the CQ-resistant reference clone W2 and two multidrug-resistant parasites recently isolated from Thailand and Cambodia. Moreover, these 4-aminoquinolines were active against early and lateP. falciparumgametocyte stages and cured BALB/c mice infected withP. berghei. TDR 58845 and TDR 58846 at 40 mg/kg were sufficient to cure mice, and total doses of 480 mg/kg of body weight were well tolerated. Our findings suggest these novel 4-aminoquinolines should be considered for development as potent antimalarials that can be used in combination to treat multidrug-resistantP. falciparumandP. vivax.

scholarly journals Antitrypanosomal effects of polyamine biosynthesis inhibitors correlate with increases in Trypanosoma brucei brucei S-adenosyl-l-methionine

1991 ◽  
Vol 274 (2) ◽  
pp. 527-533 ◽  
Author(s):  
T L Byers ◽  
T L Bush ◽  
P P McCann ◽  
A J Bitonti
Keyword(s):  
Trypanosoma Brucei ◽  
Mammalian Cells ◽  
Time Course ◽  
Fold Increase ◽  
Complete Disappearance ◽  
Trypanosoma Brucei Brucei ◽  
Irreversible Inhibitor ◽  
Polyamine Biosynthesis ◽  
Key Enzyme ◽  
Contrast Exposure

We reported recently that administration of ([(Z)-4-amino-2-butenyl]methylamino)-5′-deoxyadenosine (MDL 73811), an enzyme-activated irreversible inhibitor of S-adenosyl-L-methionine decarboxylase (AdoMetDC; EC 4.1.1.50), a key enzyme in the synthesis of spermidine, cures African trypanosome infections in mice. The precise mechanism of action of MDL 73811 was not clear because a rapid disappearance of trypanosomes from the bloodstream of treated rats occurred before significant depletion of spermidine. Administration of MDL 73811 to Trypanosoma brucei brucei-infected rats resulted in a 70% decrease in parasitaemia within 1 h and a complete disappearance of parasites by 5 h. The reduction in parasitaemia was accompanied by complete inhibition of AdoMetDC activity by 10 min after injection of MDL 73811; inhibition was sustained for at least 4 h. Polyamine levels in trypanosomes were unaffected during the first 1 h in which the marked decrease in parasitaemia was observed, but parasite AdoMet levels increased 20-fold within this time. In contrast, exposure of cultured mammalian cells to MDL 73811 resulted in only a 1.5-2-fold increase in AdoMet levels over a 6 h time course. Experiments with inhibitors of ornithine decarboxylase (ODC) also suggested that the increased AdoMet levels might be an important factor for antitrypanosomal efficacy. Trypanosomes taken from rats treated for 36 h with eflornithine, an inhibitor of ODC, were depleted of putrescine and had markedly decreased spermidine levels. These organisms also had less than 10% of control AdoMetDC activity, and had elevated decarboxy AdoMet (greater than 4000-fold) and AdoMet (up to 50-fold) levels. The methyl ester of alpha-monofluromethyl-3,4-dehydro-ornithine (delta-MFMO-CH3), which cures murine T. b. brucei infections, and the ethyl ester analogue of this compound (delta-MFMO-C2H5), which does not cure this infection, become ODC inhibitors upon hydrolysis and thus were tested for their effects on trypanosomal polyamines, AdoMet and decarboxy AdoMet levels. Although both esters of delta-MFMO depleted trypanosomal polyamines, AdoMet and decarboxy AdoMet levels were elevated in T. b. brucei from infected mice treated with delta-MFMO-CH3 but not in parasites from mice treated with the delta-MFMO-C2H5. These data suggest that inhibition of AdoMetDC, either directly with MDL 73811 or indirectly with inhibitors of ODC, apparently leads to a trypanosome-specific elevation of AdoMet. It is possible that major changes in AdoMet, rather than changes in polyamines, may be responsible for the antitrypanosomal effects of these drugs.

scholarly journals In vitro assay and in vivo effect of artemisinin in Trypanosoma brucei brucei-infected Wistar rats

2021 ◽  
Vol 1 (3) ◽  
pp. 100061
Author(s):  
Kelvin Olutimilehin Jolayemi ◽  
Mohammed Mamman ◽  
Dahiru Sani ◽  
Magdalene Ogbonneya Okoronkwo ◽  
Abubakar Usman ◽  
...  
Keyword(s):  
Trypanosoma Brucei ◽  
Wistar Rats ◽  
In Vitro Assay ◽  
Trypanosoma Brucei Brucei ◽  
Vitro Assay

scholarly journals Efficacy of Human Exposures of Gepotidacin (GSK2140944) againstEscherichia coliin a Rat Pyelonephritis Model

2019 ◽  
Vol 63 (7) ◽  
Author(s):  
Jennifer L. Hoover ◽  
Christine M. Singley ◽  
Philippa Elefante ◽  
Stephen Rittenhouse
Keyword(s):  
Time Course ◽  
Limit Of Detection ◽  
Multidrug Resistant ◽  
Mass Spectrometry Analysis ◽  
Maximal Response ◽  
Content Type ◽  
E Coli ◽  
Tract Infections

ABSTRACTGepotidacin is a first-in-class triazaacenaphthylene antibacterial that inhibits bacterial type II topoisomerases and hasin vitroactivity against a range of bacterial pathogens, includingEscherichia coli. Urinary tract infections often progress to pyelonephritis and are a worldwide problem due to the prevalence of multidrug-resistantE. colistrains. This study evaluated thein vivoefficacy of gepotidacin against four strains of multidrug-resistantE. coliin a rat pyelonephritis model. Infected rats received controlled intravenous infusions of gepotidacin every 12 h for 4 days that recreated human systemic exposures from oral gepotidacin (800 or 1,500 mg twice daily for 4 days). Liquid chromatography-tandem mass spectrometry analysis of blood samples and kidney homogenates showed that gepotidacin levels were 6- to 7-fold higher in kidneys than in blood. Across experiments with 4-day gepotidacin treatments, bacterial CFU in kidneys were reduced by 2.9 to 4.9 log10compared to pretreatment levels, and bladder CFU were reduced to the lower limit of detection (1.2 log10). The efficacies of 800- and 1,500-mg gepotidacin exposures were statistically similar. A time-course experiment indicated that a period of more than 24 h of gepotidacin treatment was required for efficacy and that 4 days were needed for maximal response. Overall, these results demonstrate that the recreated human exposures of gepotidacin studied were effective in an animal model of pyelonephritis caused by multidrug-resistantE. coliand that further evaluation for clinical use is warranted.

scholarly journals In vitro and in vivo changes observed in Trypanosoma brucei brucei-infected rats treated with artesunate and/or diminazene aceturate

2021 ◽  
Vol 18 (4) ◽  
pp. 211-220 ◽  
Author(s):  
KO Jolayemi ◽  
M. Mamman ◽  
D. Sani ◽  
M.O. Okoronkwo ◽  
J. Amaje
Keyword(s):  
Trypanosoma Brucei ◽  
Wistar Rats ◽  
Standard Dose ◽  
Total Leucocyte Count ◽  
Post Inoculation ◽  
Trypanosoma Brucei Brucei ◽  
Diminazene Aceturate ◽  
Model Control

This study evaluated in vitro and in vivo antitrypanosomal effect of artesunate and/or diminazene aceturate in Wistar rats experimentally  infected with Trypanosoma brucei brucei. In vitro screening was carried out in triplicates using 50 μl of 0.2, 2 and 20 μg/μl of artesunate as test drug; diminazene aceturate, normal saline and trypanosome-infected blood served as controls in a 96-well microtitre plate, incubated at 37˚C for 5 minutes. Efficacy was observed over a period of 60 minutes for reduced or complete trypanosomal immobilization. Results showed concentration-dependent cessation of trypanosomal motility was significantly (p < 0.001) induced by artesunate when compared to the controls. Seventy Wistar rats of both sexes weighing between 190 and 210 g were randomly divided into 7 groups (5 males and 5 females) are used for in vivo study. Groups I and II served as normal control and model control respectively. Groups III to VII were infected with Trypanosoma brucei brucei (106 trypanosomes/ml) intraperitoneally. At peak parasitaemia (8 days post-infection), group III was treated with diminazene aceturate (3.5 mg/kg) intramuscularly once while groups IV, V, VI were treated with artesunate (200, 100, 50) mg/kg orally for 5 consecutive days and group VII was treated with combination of artesunate (50 mg/kg) orally and diminazene aceturate (1.75 mg/kg) intramuscularly for 5 days. Results indicated pre-patent period of 4 days and increase in levels of parasitaemia post-inoculation. PCV, Hb concentration, RBC count, MCV, MCHC and total leucocyte count decreased significantly (p < 0.05) between days 0and 8 in groups II to VII. Following treatment, significant increases (p < 0.05) were recorded except for groups II, IV, V and VI where the rats died. Thus, combination of artesunate (50 mg/kg) and half the standard dose of diminazene aceturate was able to reduce parasitaemia and ameliorate the anaemia elicited by the trypanosomes. Keywords: Artesunate, Diminazene Aceturate, Haematology, Trypanosoma brucei brucei, Wistar rats

scholarly journals Novel S-Adenosylmethionine Decarboxylase Inhibitors for the Treatment of Human African Trypanosomiasis

2009 ◽  
Vol 53 (5) ◽  
pp. 2052-2058 ◽  
Author(s):  
Robert H. Barker ◽  
Hanlan Liu ◽  
Bradford Hirth ◽  
Cassandra A. Celatka ◽  
Richard Fitzpatrick ◽  
...  
Keyword(s):  
Serum Proteins ◽  
Kinetic Studies ◽  
Pharmacokinetic Studies ◽  
Cytochrome P450 Enzymes ◽  
Irreversible Inhibitor ◽  
Brain Penetration ◽  
Adenosylmethionine Decarboxylase ◽  
Highly Active

ABSTRACT Trypanosomiasis remains a significant disease across the sub-Saharan African continent, with 50,000 to 70,000 individuals infected. The utility of current therapies is limited by issues of toxicity and the need to administer compounds intravenously. We have begun a program to pursue lead optimization around MDL 73811, an irreversible inhibitor of S-adenosylmethionine decarboxylase (AdoMetDC). This compound is potent but in previous studies cleared rapidly from the blood of rats (T. L. Byers, T. L. Bush, P. P. McCann, and A. J. Bitonti, Biochem. J. 274:527-533). One of the analogs synthesized (Genz-644131) was shown to be highly active against Trypanosoma brucei rhodesiense in vitro (50% inhibitory concentration, 400 pg/ml). Enzyme kinetic studies showed Genz-644131 to be approximately fivefold more potent than MDL 73811 against the T. brucei brucei AdoMetDC-prozyme complex. This compound was stable in vitro in rat and human liver microsomal and hepatocyte assays, was stable in rat whole-blood assays, did not significantly inhibit human cytochrome P450 enzymes, had no measurable efflux in CaCo-2 cells, and was only 41% bound by serum proteins. Pharmacokinetic studies of mice following intraperitoneal dosing showed that the half-life of Genz-644131 was threefold greater than that of MDL 73811 (7.4 h versus 2.5 h). Furthermore, brain penetration of Genz-644131 was 4.3-fold higher than that of MDL 73811. Finally, in vivo efficacy studies of T. b. brucei strain STIB 795-infected mice showed that Genz-644131 significantly extended survival (from 6.75 days for controls to >30 days for treated animals) and cured animals infected with T. b. brucei strain LAB 110 EATRO. Taken together, the data strengthen validation of AdoMetDC as an important parasite target, and these studies have shown that analogs of MDL 73811 can be synthesized with improved potency and brain penetration.

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