Quinapyramine Sulfate Research Articles

Parasitological, Serological and Molecular Prevalence of Trypanosoma evansi among Arabian Camels (Camelus dromedaries) with Evaluation of Antitrypanosomal Drugs.

This study was carried out to assess the prevalence of Trypanosoma evansi infection in naturally diseased Dromedary camels in Dammam, Eastern region of Saudi Arabia. The detection of Trypanosoma evansi was performed using the parasitological, serological, and molecular diagnosis and a comparison between such methods were analyzed. In addition, evaluation of therapeutic efficacy of selected antitrypanosomal drugs, cymelarsan and quinapyrmine (aquin-1.5), was trialed for treatment of diagnosed infected cases. A total 350 randomly selected camels were evaluated using thin blood smear (TBS), RoTat1.2 PCR and CATT/T. evansi techniques. The total prevalence was 6.9%, 7.7%, and 32.8% by TBS, RoTat1.2 PCR and CATT/T. evansi techniques, respectively. Although PCR detect T. evansi in more samples than TBS, the agreement was good (K = 0.9). Among the CATT/T. evansi results, PCR detect T. evansi in 12 and 15 CATT positive and negative camels, respectively, with low agreement (Kappa = 0.1). The use of cymelarsan and quinapyramine sulfate in the treatment of naturally infected cases demonstrated a very efficient therapeutic response. It was found that 1. Comparing the CATT/T. evansi and PCR results, the positivity of CATT was higher than PCR detection, while the agreement was poor (K = 0.1). 2. Cymelarsan and aquin-1.5 proved to be effective in the treatment of naturally infected camels, but cymelarsan presented with higher effectiveness (100%) than aquin-treated camels (83.3%). a 3. The use of cymelarsan and CATT is recommended for disease treatment and control.

Intracellular ROS production and apoptotic effect of quinoline and isoquinoline alkaloids on the growth of Trypanosoma evansi

Trypanosoma evansi, a hemoflagellate poses huge economic threat to the livestock industry of several countries of Asia, Africa, South America and Europe continents of the world. Limited number of available chemical drugs, incidents of growing drug resistance, and related side effects encouraged the use of herbal substitutes. In the present investigation, the impact of six alkaloids of quinoline and isoquinoline group was evaluated on the growth and multiplication of Trypanosoma evansi and their cytotoxic effect was examined on horse peripheral blood mononuclear cells in an in vitro system. Quinine, quinindine, cinchonine, cinchonidine, berbamine and emetine showed potent trypanocidal activities with IC50/24 h values 6.631 ± 0.244, 8.718 ± 0.081, 16.96 ± 0.816, 33.38 ± 0.653, 2.85 ± 0.065, and 3.12 ± 0.367 µM, respectively, which was comparable to the standard anti-trypanosomal drug, quinapyramine sulfate (20 µM). However, in the cytotoxicity assay, all the drugs showed dose dependent cytotoxic effect and quinine, berbamine and emetine showed selectivity index more than 5, based of ration of CC50 to IC50. Among the selected alkaloids, quinidine, berbamine and emetine exhibited higher apoptotic effects in T. evansi. Likewise, drug treated parasites showed a dose-dependent and time-dependent increase in reactive oxygen species (ROS) production. Therefore, increased apoptosis in combination with ROS generation could be responsible for the observed trypanocidal effect which could be further evaluated in T. evansi-infected mice model.

An Update on African Trypanocide Pharmaceutics and Resistance

African trypanosomiasis is associated with Trypanosoma evansi, T. vivax, T. congolense, and T. brucei pathogens in African animal trypanosomiasis (AAT) while T. b gambiense and T. b rhodesiense are responsible for chronic and acute human African trypanosomiasis (HAT), respectively. Suramin sodium suppresses ATP generation during the glycolytic pathway and is ineffective against T. vivax and T. congolense infections. Resistance to suramin is associated with pathogen altered transport proteins. Melarsoprol binds irreversibly with pyruvate kinase protein sulfhydryl groups and neutralizes enzymes which interrupts the trypanosome ATP generation. Melarsoprol resistance is associated with the adenine-adenosine transporter, P2, due to point mutations within this transporter. Eflornithine is used in combination with nifurtimox. Resistance to eflornithine is caused by the deletion or mutation of TbAAT6 gene which encodes the transmembrane amino acid transporter that delivers eflornithine into the cell, thus loss of transporter protein results in eflornithine resistance. Nifurtimox alone is regarded as a poor trypanocide, however, it is effective in melarsoprol-resistant gHAT patients. Resistance is associated with loss of a single copy of the genes encoding for nitroreductase enzymes. Fexinidazole is recommended for first-stage and non-severe second-stage illnesses in gHAT and resistance is associated with trypanosome bacterial nitroreductases which reduce fexinidazole. In AAT, quinapyramine sulfate interferes with DNA synthesis and suppression of cytoplasmic ribosomal activity in the mitochondria. Quinapyramine sulfate resistance is due to variations in the potential of the parasite's mitochondrial membrane. Pentamidines create cross-links between two adenines at 4–5 pairs apart in adenine-thymine-rich portions of Trypanosoma DNA. It also suppresses type II topoisomerase in the mitochondria of Trypanosoma parasites. Pentamidine resistance is due to loss of mitochondria transport proteins P2 and HAPT1. Diamidines are most effective against Trypanosome brucei group and act via the P2/TbAT1 transporters. Diminazene aceturate resistance is due to mutations that alter the activity of P2, TeDR40 (T. b. evansi). Isometamidium chloride is primarily employed in the early stages of trypanosomiasis and resistance is associated with diminazene resistance. Phenanthridine (homidium bromide, also known as ethidium bromide) acts by a breakdown of the kinetoplast network and homidium resistance is comparable to isometamidium. In humans, the development of resistance and adverse side effects against monotherapies has led to the adoption of nifurtimox-eflornithine combination therapy. Current efforts to develop new prodrug combinations of nifurtimox and eflornithine and nitroimidazole fexinidazole as well as benzoxaborole SCYX-7158 (AN5568) for HAT are in progress while little comparable progress has been done for the development of novel therapies to address trypanocide resistance in AAT.

Clinical and therapeutic aspects of an outbreak of canine trypanosomiasis.

Trypanosomiasis caused by Trypanosoma evansi can seriously affect both domestic and wild animals. This article reports on an outbreak of canine trypanosomiasis on a farm in the Pantanal region of Brazil. The farm had 38 dogs, 20 of which died before receiving veterinary care. The remaining 18 dogs were underwent anamnesisn, clinical examination, hematological and biochemical evaluations. Blood smears and PCR analysis were performed for the diagnosis. The treatment protocols used according to the clinical recovery or parasitological cure of the dogs, using diminazene diaceturate, isometamidium chloride or quinapyramine sulfate. Post-treatment parasitological evaluation was performed by the microhematocrit technique. 7/18 dogs were PCR positive for T. evansi (confirmed by sequencing). There was clinical findings, which were consistent with both the acute and chronic stages of the disease in dogs. The infected dogs all exhibited at least one clinical sign of the disease. The hematological findings were compatible with trypanosomiasis, highlighting the hypochromic microcytic anemia as the main outcome. No treatment protocol was fully effective and the prolonged use of diminazene diaceturate caused the death of an animal. The trypanosomiasis can cause high rates of morbidity and mortality in dogs and difficulty in establishment an effective and safe therapeutic protocol.

Biocompatibility and Targeting Efficiency of Encapsulated Quinapyramine Sulfate-Loaded Chitosan-Mannitol Nanoparticles in a Rabbit Model of Surra.

Quinapyramine sulfate (QS) produces trypanocidal effects against the parasite Trypanosoma evansi but is often poorly tolerated and causes serious reactions in animals. The encapsulation of QS in chitosan-mannitol to provide sustained release would improve both the therapeutic effect of QS and the quality of life of animals treated with this formulation. QS was encapsulated into a nanoformulation prepared from chitosan, tripolyphosphate, and mannitol nanomatrix (ChQS-NPs). ChQS-NPs were well ordered in shape, with nanoparticle size, as determined by transmission electron microscopy and atomic force microscopy. Our research revealed dose-dependent effects on biosafety and DNA damage in mammalian cells treated with ChQS-NPs. ChQS-NPs were absolutely risk-free at effective as well as many times higher doses against T. evansi ChQS-NPs were effective in rabbits, as they killed the parasites, relieving the animals from the clinical symptoms of the disease. The extent of this protection was similar to that observed with the conventional drug at higher dosages (5 mg QS/kg of body weight). ChQS-NPs are safe, nontoxic, and more effective than QS and offer a promising alternative to drug delivery against surra in animal models. ChQS-NPs may be useful for the treatment of surra due to reduced dosages and frequency of administration.

Chitosan quinapyramine sulfate nanoparticles exhibit increased trypanocidal activity in mice

An aminoquinaldine derivative, quinapyramine sulfate (QS) is the commonly used and effective drug for treatment of Trypanosoma evansi infection. It produces the trypanocidal effect, but often poorly tolerated causes serious local reactions. The encapsulation of QS in Chitosan/mannitol nanoparticles to provide sustained release would improve the therapeutic effect of QS. QS was encapsulated into nanoformulation (ChQS-NPs) prepared from a Chitosan, tripolyphosphate and mannitol nanomatrix. ChQS-NPs showed an initial burst followed by slow release exhibiting quasi-fickian Higuchi diffusion mechanism. Our experiments revealed a dose-dependent safety/cytotoxicity (metabolic activity), in ChQS NPs treated mammalian cells. ChQS NPs were safe at effective trypanocidal doses and even at doses several times higher than the effective dose. ChQS-NPs produced a trypanocidal effect in mice and cleared the parasite at a highly reduced dose (QS 0.85 mg/kg bw) along with the sustained release. The extent of this protection was similar to that observed with the conventional drug with higher dosages (5mg QS/Kg bw). ChQS-NPs are safe, less toxic and effective as compared to the conventional QS and offer a promising alternative for drug-delivery against trypanosomosis in higher animal models.

Cytotoxicity and genotoxicity of a trypanocidal drug quinapyramine sulfate loaded-sodium alginate nanoparticles in mammalian cells

We synthesized quinapyramine sulfate loaded-sodium alginate nanoparticles (QS-NPs) to reduce undesirable toxic effects of QS against the parasite Trypanosoma evansi, a causative agent of trypanosomosis. To determine the safety of the formulated nanoparticles, biocompatibility of QS-NPs was determined using Vero, Hela cell lines and horse erythrocytes in a dose-dependent manner. Our experiments unveiled a concentration-dependent safety/cytotoxicity (metabolic activity), genotoxicity (DNA damage, chromosomal aberrations), production of reactive oxygen species and hemolysis in QS-NPs treated cells. Annexin-V propidium iodide (PI) staining showed no massive apoptosis or necrosis. However, at very high doses (more than 300 times than the effective doses), we observed more toxicity in QS-NPs treated cells as compared to QS treated cells. QS-NPs were safe at effective trypanocidal doses and even at doses several times higher than the effective dose.

Zoonotic trypanosomes in South East Asia: Attempts to control Trypanosoma lewisi using veterinary drugs

A growing number of atypical human infections due to the livestock parasite Trypanosoma evansi, or to the rat parasite Trypanosoma lewisi, are reported in humans in Asia. In some cases, clinical evolutions request treatments, however, so far, there were very few attempts to control T. lewisi using trypanocidal drugs. In a study published elsewhere, the efficacy of human trypanocides is evaluated in laboratory rats, and it concludes that none of them is able to cure rats experimentally infected with T. lewisi. Control of T. lewisi in rat would be a step for identification of drugs against this parasite. In the present study, 4 veterinary drugs: diminazene aceturate, isometamidium chloride, melarsomine hydrochloride and quinapyramine sulfate and chloride, were evaluated at low and high doses, in intra-muscular injections to normal rats experimentally infected with a stock of T. lewisi from Thailand. None of these treatments being efficient, a trial was also made using melarsomine hydrochloride in T. evansi infected rats and in mixed T. lewisi and T. evansi infected rats, in order to demonstrate the efficacy of the drugs under the present protocol. T. evansi was cleared from the rat's blood the day after the treatment, while, T. lewisi remained unaffected until the end of the experiment. These observations clearly demonstrated the efficacy of melarsomine hydrochloride against T. evansi and its inefficacy against T. lewisi. In conclusion none of the veterinary drugs was efficient against this stock of T. lewisi. Other protocols using higher doses or other drugs and T. lewisi stocks should be investigated in further studies. The control of T. lewisi infection in Wistar rats, using veterinary trypanocidal drugs, remains so far unsuccessful.

Quinapyramine Sulfate-Loaded Sodium Alginate Nanoparticles Show Enhanced Trypanocidal Activity

To reduce the dose, toxic effects and to ensure sustained release of quinapyramine sulfate (QS), a highly effective drug against Trypanosoma evansi. QS-loaded sodium alginate nanoparticles (QS-NPs) were formed by emulsion-crosslinking technology using dioctyl-sodium-sulfosuccinate and sodium alginate. The formulation was characterized for size, stability, morphology and functional groups by a zetasizer, scanning electron microscopy, atomic force microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. In vitro safety and toxicity studies were performed by metabolic assay in Vero cell lines, and in vivo efficacy was evaluated in mice. QS-NPs were <60 nm with 96.48% entrapment efficiency and 3.70% drug loading. The formulation showed an initial burst effect followed by slow drug release in accordance with quasi-Fickian Higuchi diffusion mechanism. QS-NPs were much less toxic and able to clear the parasite at a much lower concentration than QS. The QS-NPs synthesized are safe, less toxic and highly effective compared with QS.

Neurological trypanosomiasis in quinapyramine sulfate-treated horses—a breach of the blood–brain barrier?

Trypanosoma evansi infection typically produces wasting disease, but it can also develop into a neurological or meningoencephalitis form in equids. Trypanosomiasis in horses was treated with quinapyramine sulfate, and all the 14 infected animals were recovered clinically. After clinical recovery, four animals developed a neurological form of the disease at various intervals. Two of these animals treated with diminazene aceturate recovered temporarily. Repeated attempts failed to find the parasite in the blood or the cerebrospinal fluid (CSF), but all of the animals were positive in enzyme-linked immunosorbent assay. The calculation of the antibody index (AI) in the serum and the CSF and polymerase chain reaction (PCR) analysis of the CSF and brain tissue were carried out to confirm the neuro-infection. We found PCR and AI analyses of the CSF to be useful tools in the diagnosis of the neurological form of trypanosomiasis when the organism cannot be found in the blood or CSF. The increased albumin quotient is indicative of barrier leakage due to neuroinflammation. The biochemical changes in the CSF due to nervous system trypanosomiasis include increases in the albumin quotient, total protein, and urea nitrogen. It seems to be the first report on relapse of the nervous form of trypanosomiasis in equids even after quinapyramine treatment in endemic areas.

Derivation and characterization of a quinapyramine-resistant clone of Trypanosoma congolense.

Over a period of 208 days a quinapyramine-resistant population was derived in vivo from a quinapyramine-susceptible clone of Trypanosoma congolense: IL 1180. While the dose of quinapyramine sulfate required to cure 50% of mice infected with the parental clone was 0.23 mg/kg of body weight, the 50% curative dose for the resistant derivative, IL 1180/Stabilate 12, was greater than 9.6 mg/kg. This approximately 40-fold increase in resistance to quinapyramine was shown to be associated with an 8-fold increase in resistance to isometamidium, a 28-fold increase in resistance to homidium, and a 5.5-fold increase in resistance to diminazene. Cross-resistance to homidium and diminazene was also demonstrated in goats. Two clones derived from the drug-resistant derivative underwent cyclical development in Glossina morsitans centralis, producing mature infection rates of 39.6 and 23.9%. Thus, induction of resistance to quinapyramine in T. congolense IL 1180 was associated with cross-resistance to isometamidium, homidium, and diminazene and did not compromise the population's ability to undergo full cyclical development in tsetse flies.

In vivo and in vitro sensitivity of Trypanosoma evansi and T. equiperdum to diminazene, suramin, MelCy, quinapyramine and isometamidium

The sensitivity of three Trypanosoma equiperdum clones and thirteen Trypanosoma evansi clones originating from the People's Republic of China, the Philippines, Ethiopia and elsewhere to a series of drugs was determined in vivo and in vitro. The drugs tested were diminazene aceturate (Berenil), suramin (Naganol), MelCy (Cymelarsan), quinapyramine sulfate (Trypacide) and isometamidium chloride (Samorin). The activity of each drug was expressed as: 1) in vitro: the minimal effective concentration which killed trypanosome population by 100% within 24 h of drug exposure (MEC 100); the maximum tolerated concentration in which trypanosomes could propagate at the same rate as the controls during 48 h of drug exposure (MTC 100); 2) in vivo: the curative dosage in 100% of infected mice (CD 100); the highest ineffective dosage: 100% of infected mice remain infected (ID 100). MEC 100 values of diminazene aceturate ranged from 0.0556 μg/ml to 14.24 μg/ml for the eleven tested clones (differed by 256-fold); CD 100 values of this drug ranged from 2.25 mg/kg to > 89 mg/kg (differed by >40-fold). Diminazene aceturate at up to 89 mg/kg had no effect on T. evansi SHBR, T. equiperdum PBR (Berenil resistant organisms selected by continual passage of the organisms through mice treated with increasing concentrations of drug), or T. evansi AH (strain isolated in the field). Comparable MEC 100 values for other trypanocides tested were 1–8 μg/ml for suramin, 0.005–0.04 μg/ml for MelCy, 1–16 μg/ml for quinapyramine sulfate and 1–4 μg/ml for isometamidium chloride. Clones selected for resistance to diminazene aceturate were not cross-resistant to suramin and isometamidium chloride. In contrast, the clones resistant to diminazene were shown to be more sensitive to quinapyramine sulfate than the normal strains in in vivo tests. The results indicate that resistance to diminazene aceturate by T. evansi and T. equiperdum clones in vivo also occurred in vitro. Resistance to isometamidium chloride in the clones tested in vivo was not observed in vitro, except for T. equiperdum SA. It therefore appears that drug bioavailability is altered or drug biotransformation occurs during the in vivo test. We conclude that the in vitro assay procedure may be of potential use for screening new trypanocides and also for the rapid detection of drug resistant isolates of T. evansi and T. equiperdum.

Effect of In vitro Cultivation on the Stability of Resistance of Trypanosoma brucei brucei to Diminazene, Isometamidium, Quinapyramine, and Mel B

A Trypanosoma brucei brucei stock resistant to diminazene aceturate, isometamidium chloride, quinapyramine sulfate, and Mel B was grown in vitro and its response to these drugs compared to that of a drug-sensitive trypanosome stock. There was little if any change of drug sensitivity after in vitro propagation as bloodstream forms for 120, 177, and 275 days and after in vitro transformation of bloodstream forms into procyclic, epimastigote, and finally metacyclic forms. Drug resistance was stable during in vitro maintenance in the absence of drugs in both culture systems. The response of resistant and sensitive T. b. brucei to diminazene in vitro correlated with their sensitivity pattern in vivo. Thus, in vitro techniques can be used to study drug resistance in trypanosomes.

Efficacy of experimental trypanocidal compounds against a multiple drug-resistant Trypanosoma brucei brucei stock in mice.

Several experimental trypanocidal compounds, 6-amidino-2-(4-amidinophenyl)indole dilactate (DAPI), DL-alpha-difluoromethylornithine (DFMO), 2-(dimethylamino)-4'-[(1-methyl-2-nitroimidazole-5-yl) methoxy] aceto-anilide (Ro 15-0216), sinefungin, and triacetylbenzene-tris(guanylhydrazone)trimethanesulfonate hydrate (TBG-MS) were tested to evaluate their ability to cure mouse infections with a multiple drug-resistant Trypanosoma brucei brucei stock (CP 547). This stock proved to be drug-resistant against diminazene aceturate, homidium chloride, isometamidium, quinapyramine sulfate, Mel B, and pentamidine isethionate but fully sensitive to suramin. Compared with the sensitive stock CP 462, the drug-resistant stock CP 547 was completely resistant to 16-fold the curative dose of sinefungin and partially resistant to 4-fold the curative dose of DAPI and to 13-fold the curative dose of TBG-MS, a dose that killed 25% of the animals due to its toxicity. Ro 15-0216 cured all mice when 18 times the usual curative dose level was given. DFMO was equally effective against both stocks.