Parasitemia In Mice Research Articles

Naringin and chloroquine combination mitigates chloroquine-resistant parasite-induced malaria pathogenesis by attenuating the inflammatory response

BackgroundMalaria, characterised by inflammation and multi-organ complications, needs novel chemotherapeutics due to the rise of drug-resistant malaria parasites, which is a serious health issue. Naringin (NGN), a flavanone glycoside (naringenin 7-O-neohesperidose), has a broad spectrum of pharmacological activities but its effect against malaria, alone and in combination, was not deeply investigated. PurposeTo assess the pharmacological efficacy of NGN alone and in combination with chloroquine (CQ) against a Plasmodium strain resistant to CQ and to elucidate its potential mode of action. MethodsThe anti-inflammatory potential of NGN was assessed in mouse microglial cells stimulated with hemozoin by analyzing inflammatory cytokines production. The anti-plasmodial potential of NGN was subsequently tested alone and in combination with CQ against the K1 strain of Plasmodium using the fixed ratio combination method. Further, we evaluated NGN's antimalarial efficacy against the CQ-resistant Plasmodium yoelii nigeriensis N67 strain (P. yoelii), both alone and in combination with CQ, by measuring parasitemia and survival rates. To comprehend the impact of NGN on malaria-induced inflammation in mice, we measured pro-inflammatory cytokines elevated by activated NF-кB signalling. These findings were supported by mRNA and immunohistochemical analyses of malaria-infected mice's liver and brain tissues. ResultsOur study demonstrated that NGN displayed anti-plasmodial activity, which was further augmented when combined with CQ. At 50 µM, NGN significantly reduced the elevation of pro-inflammatory cytokines in synthetic hemozoin-stimulated microglial cells. Compared to P. yoelii-infected mice, NGN (12.5 mg kg-1) significantly reduced parasitemia in mice, resulting in a survival period of up to 13 days. Survival improved by up to 20 days when NGN and CQ were given in combination. NGN, as revealed by immunohistochemical examination of brain and liver tissues, interfered with the NF-кB pathway, potentially reducing the elevation of pro-inflammatory cytokines (TNF-α, IL-1β, IL-18, IFN-γ, and IL-6). This was supported by the overexpression of inflammation-regulatory genes (TGFβ, Nrf2, HO-1, and iNOS) and the downregulation of inflammation-stimulating genes (NF-κB, NLRP3, and caspase-1). Histopathological analysis demonstrated the potential of NGN to restore liver and brain tissues to normal. The substantial decrease in the expression and production of ICAM-1 protein in the brain tissue implies the beneficial effects of NGN, pointing towards its potential for mitigating brain pathology. ConclusionThe findings of this study revealed NGN as a promising drug-like candidate for the management of CQ-resistant parasite-induced malaria pathogenesis for adjunctive therapy in combination with standard antimalarial drugs through its modulation of the NF-κB-mediated inflammation.

Metabolite Profiling of the Extract and Antimalarial Activity of the Tablets Derived from the Cortex of Alstonia spectabilis

Malaria is a global health concern that threatens many countries. Plasmodium sp. may facilitate human transmission and is currently relatively resistant to chloroquine. The people in Nusa Tenggara, Indonesia, have traditionally employed the cortex of Black Pulai (Alstonia spectabilis) as a treatment for malaria for a considerable period. The objective of this study is to analyze the phytochemical composition of the 96% ethanol extract of A. spectabilis cortex (ASCE) and evaluate the antimalarial properties of tablets derived from A. spectabilis cortex extract (ASCT). A metabolite profile analysis was conducted on ASCE utilizing a UPLC-QToF-MS/MS method. And antimalarial test was conducted on ASCT on mice (Mus musculus) infected with Plasmodium berghei, and the blood smears of the mice were analyzed along with liver tissue damage. The results showed that administering ASCT could reduce the percentage of parasitemia in mice as well as the average liver damage score. This situation is feasible due to the presence of significant compounds in the ASCE that are anticipated to function as antiplasmodium agents, including villalstonine, vincadifformine, and pleiocarpamine. From these findings, one can infer that ASCT, which includes ASCE as its active component, has the potential to serve as a preferred antimalarial medication.

Assessment of antimalarial activity of crude extract of Chan-Ta-Lee-La and Pra-Sa-Chan-Dang formulations and their plant ingredients for new drug candidates of malaria treatment: In vitro and in vivo experiments.

The emergence and spread of antimalarial drug resistance have become a significant problem worldwide. The search for natural products to develop novel antimalarial drugs is challenging. Therefore, this study aimed to assess the antimalarial and toxicological effects of Chan-Ta-Lee-La (CTLL) and Pra-Sa-Chan-Dang (PSCD) formulations and their plant ingredients. The crude extracts of CTLL and PSCD formulations and their plant ingredients were evaluated for in vitro antimalarial activity using Plasmodium lactate dehydrogenase enzyme and toxicity to Vero and HepG2 cells using the tetrazolium salt method. An extract from the CTLL and PSCD formulations exhibiting the highest selectivity index value was selected for further investigation using Peter's 4-day suppressive test, curative test, prophylactic test, and acute oral toxicity in mice. The phytochemical constituents were characterized using gas chromatography-mass spectrometry (GC-MS). Results showed that ethanolic extracts of CTLL and PSCD formulations possessed high antimalarial activity (half maximal inhibitory concentration = 4.88, and 4.19 g/mL, respectively) with low cytotoxicity. Ethanolic extracts of the CTLL and PSCD formulations demonstrated a significant dose-dependent decrease in parasitemia in mice. The ethanolic CTLL extract showed the greatest suppressive effect after 4 days of suppressive (89.80%) and curative (35.94%) testing at a dose of 600 mg/kg. Moreover, ethanolic PSCD extract showed the highest suppressive effect in the prophylactic test (65.82%) at a dose of 600 mg/kg. There was no acute toxicity in mice treated with ethanolic CTLL and PSCD extracts at 2,000 mg/kg bodyweight. GC-MS analysis revealed that the most abundant compounds in the ethanolic CTLL extract were linderol, isoborneol, eudesmol, linoleic acid, and oleic acid, whereas ethyl 4-methoxycinnamate was the most commonly found compound in the ethanolic PSCD extract, followed by 3-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-4H-chromen-4-one, flamenol, oleic acid amide, linoleic acid, and oleic acid. In conclusions, ethanolic CTLL and PSCD extracts exhibited high antimalarial efficacy in vitro. The ethanolic CTLL extract at a dose of 600 mg/kg exhibited the highest antimalarial activity in the 4-day suppressive and curative tests, whereas the ethanolic PSCD extract at a dose of 600 mg/kg showed the highest antimalarial activity in the prophylactic test.

Lycopene supplementation promoted increased survival and decreased parasitemia in mice with severe malaria: comparison with N-acetylcysteine.

Oxidative stress is involved in the pathogenesis of malaria, causing anemia, respiratory complications, and cerebral malaria. To mitigate oxidative stress, we investigated the effect of nutritional supplementation whit lycopene (LYC) on the evolution of parasitemia and survival rate in mice infected with Plasmodium berghei ANKA (Pb), comparing to the effects promoted by N-acetylcysteine (NAC). Therefore, 175 mice were randomly distributed into 4 groups; Sham: untreated and uninfected animals; Pb: animals infected with Pb; LYC+Pb: animals treated with LYC and infected with Pb; NAC+Pb: animals treated with NAC and infected with Pb. The animals were followed for 12 days after infection, and survival and parasitemia rates were evaluated. There was a 40.1% increase in parasitemia in the animals of the Pb group on the 12th day, and a survival rate of 45%. LYC supplementation slowed the development of parasitemia to 19% and promoted a significative increase in the survival rate of 80% on the 12th day after infection, compared to the Pb group, effects superior to those promoted by NAC, providing strong evidence of the beneficial effect of LYC on in vivo malaria and stressing the importance of antioxidant supplementation in the treatment of this disease.

Propriedades supressoras da bile de ovelha contra o parasita Plasmodium chabaudi em camundongos

ABSTRACT Plasmodium species are responsible for the transmission of malaria, which is still one of the most dangerous diseases to humans in the world. This study aimed to evaluate the suppressive effect of SB on parasitemia in mice infected with Plasmodium chabaudi infection. A total of 30 disease-free mice were randomly assigned to six groups. The first control non-infected group received only distilled water daily for 7 days by oral route. After being infected with 106 of P. chabaudi in the other five groups, the mice were gavaged with 0.2mL/mice of a solution containing either 25%, 50%, or 100% of SB, respectively. The fifth group orally received 10mg/ kg chloroquine phosphate (CQ). The sixth set of mice served as the infected group. Following the administration of treatments during a suppression test that lasted for five days, a daily examination of blood smears stained with Giemsa was performed. Sheep bile was able to decrease parasitemia nearly to the used reference drug, chloroquine. In addition, bile significantly decreased the diarrhea rate of infection in mice, the survival rate of mice, the parasitemia percentage, and the suppression ratio. The parasite's caused histological change was enhanced by the SB. After treatment, there was also a rise in the amounts of the liver enzymes alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase. Findings indicate that bile has antimalarial activity and can control parasitemia percentage and parasite suppression. We need further investigations to determine the mechanisms of action of the bile in vivo.

Evaluation of Antimalarial Activities of the Hydroalcoholic Extracts of Artemisia persica and Artemisia spicigera Against Plasmodium berghei in Albino Mice

Background: Malaria, a life-threatening disease caused by Plasmodium parasites, continues to be a major global health concern. The emergence of drug-resistant strains of Plasmodium highlights the urgent need for new antimalarial agents. Objectives: This study aimed to evaluate the antimalarial activity of hydroalcoholic extracts obtained from Artemisia persica and Artemisia spicigera against Plasmodium berghei in albino mice. Materials and Methods: In this study, the hydroalcoholic extracts of the aerial parts of A. spicigera and A. persica were investigated for their effects on parasitemia in mice. Fifty mice were randomly divided into two categories with five groups, with each group receiving either the extract of A. spicigera, A. persica, or a control treatment. Results: Both extracts of A. persica and A. spicigera inhibited parasitemia on average by 75% and 83.5%, respectively. There was a significant increase in parasitemia at 150 mg/kg of A. persica compared with the negative control group on day 4 (P<0.05). Significant internment of parasitemia was illustrated at 75 mg/kg of A. spicigera in comparison to the negative control group on day 4 (P<0.05). Conclusion: The findings elucidated that hydroalcoholic extracts of A. persica and A. spicigera plants have the antiplasmodial action to suppress P. berghei infection in mice.

Exploring the Potential of Crude Methanolic Leaf Extract of Gossypium Hirsutum in Malaria Treatment, Pain Relief, and Inflammation Reduction

The increasing resistance of Plasmodium falciparum to standard anti-malarial drugs has led to a search for new compounds with antimalarial properties. Throughout history, various plants have been used for the treatment of malaria. Gossypium hirsutum, a plant commonly used in Ondo state for malaria treatment, was the focus of this study. The crude extracts of Gossypium hirsutum were evaluated for their anti-plasmodial, analgesic, and anti-inflammatory properties. To assess the anti-plasmodial effect, Plasmodium berghei was inoculated into 12 mice divided into four groups, with three mice in each group. Groups 1 and 2 were treated with doses of 200mg/kg.bw and 400mg/kg.bw of the crude plant extract, respectively. Group 3 received 5mg/kg.bw of chloroquine phosphate, while group 4 received normal saline. The analgesic effects were evaluated using the Eddy's hot plate method and the Tail flick method in mice. The anti- inflammatory effect was assessed using egg albumin-induced paw edema in rats. The crude methanolic extracts of Gossypium hirsutum demonstrated activity against Plasmodium parasites and a significant anti-inflammatory effect, suppressing paw edema by 49.7%. Animals administered with the extracts showed increased resptime to thermal pain induction in both the hot plate and tail flick methods, similar to the effect oonse bserved with the standard drug. The crude plant extract reduced parasitemia in mice by 79.2%, accompanied by a slight but statistically insignificant decrease in packed cell volume (PCV) and the weight of treated animals. Overall, the crude extract of Gossypium hirsutum exhibited effectiveness in managing malaria, along with a moderate analgesic and anti-inflammatory potential. These findings suggest that the plant contains active compounds with promising antimalarial effects, which could be further isolated and studied.

Quinine: Redesigned and Rerouted

Quinine hydrochloride (QHCl) has remained a very relevant antimalarial drug 400 years after its effectiveness was discovered. Unlike other antimalarials, the development of resistance to quinine has been slow. Hence, this drug is to date still used for the treatment of severe and cerebral malaria, for malaria treatment in all trimesters of pregnancy, and in combination with doxycycline against multidrug-resistant malaria parasites. The decline in its administration over the years is mainly associated with poor tolerability due to its gastrointestinal (GIT) side effects such as cinchonism, complex dosing regimen and bitter taste, all of which result in poor compliance. Hence, our research was aimed at redesigning quinine using nanotechnology and investigating an alternative route for its administration for the treatment of malaria. QHCl nanosuspension (QHCl-NS) for intranasal administration was prepared using lipid matrices made up of solidified reverse micellar solutions (SRMS) comprising Phospholipon® 90H and lipids (Softisan® 154 or Compritol®) in a 1:2 ratio, while Poloxamer® 188 (P188) and Tween® 80 (T80) were used as a stabilizer and a surfactant, respectively. The QHCl-NS formulated were in the nanosize range (68.60 ± 0.86 to 300.80 ± 10.11 nm), and highly stable during storage, though zeta potential was low (≤6.95 ± 0.416). QHCl-NS achieved above 80% in vitro drug release in 6 h. Ex vivo permeation studies revealed that formulating QHCl as NS resulted in a 5-fold and 56-fold increase in the flux and permeation coefficient, respectively, thereby enhancing permeation through pig nasal mucosa better than plain drug solutions. This implies that the rate of absorption as well as ease of drug permeation through porcine nasal mucosa was impressively enhanced by formulating QHCl as NS. Most importantly, reduction in parasitaemia in mice infected with Plasmodium berghei ANKA by QHCl-NS administered through the intranasal route (51.16%) was comparable to oral administration (52.12%). Therefore, redesigning QHCl as NS for intranasal administration has great potential to serve as a more tolerable option for the treatment of malaria in endemic areas.

The differences of parasitemia in Plasmodium berghei infected mice treated with extract of mango parasite leaves with Artemisinin combination

Malaria is a disease transmitted through the bite of a female Anopheles mosquito caused by the Plasmodium parasite. Plasmodium has been reported to become resistant to artemisinin. Thus, the study on the ethanol extract of mango parasite leaves/Dendrophthoe pentandra (MP) on P. berghei-infected BALB/c mice with and without artemisinin combination (MP+A) was conducted. This study is experimental laboratory research with a post-test only design. The percent parasitemia in mice treated with ethanol extract of MP and MP+A leaves decreased. There was no difference in the spleen index in mice given ethanol extract of MP, and MP+A leaves with p = 0.203 and the spleen weight of mice with p = 0.134 (significance: p <0.005). Pearson Correlation test showed a correlation between spleen index with parasitemia and spleen weight with parasitemia; however, there was no correlation between body weight and parasitemia. The ethanol extracts of MP and MP+A leaves had significant antimalarial activity, and the difference in the percent parasitemia between groups was significant but not so far. The spleen index value was not affected by the ethanol extract of MP and MP+A leaves, but the percent parasitemia was affected.

The Multistage Antimalarial Compound Calxinin Perturbates P. falciparum Ca2+ Homeostasis by Targeting a Unique Ion Channel.

Malaria elimination urgently needs novel antimalarial therapies that transcend resistance, toxicity, and high costs. Our multicentric international collaborative team focuses on developing multistage antimalarials that exhibit novel mechanisms of action. Here, we describe the design, synthesis, and evaluation of a novel multistage antimalarial compound, ‘Calxinin’. A compound that consists of hydroxyethylamine (HEA) and trifluoromethyl-benzyl-piperazine. Calxinin exhibits potent inhibitory activity in the nanomolar range against the asexual blood stages of drug-sensitive (3D7), multidrug-resistant (Dd2), artemisinin-resistant (IPC4912), and fresh Kenyan field isolated Plasmodium falciparum strains. Calxinin treatment resulted in diminished maturation of parasite sexual precursor cells (gametocytes) accompanied by distorted parasite morphology. Further, in vitro liver-stage testing with a mouse model showed reduced parasite load at an IC50 of 79 nM. A single dose (10 mg/kg) of Calxinin resulted in a 30% reduction in parasitemia in mice infected with a chloroquine-resistant strain of the rodent parasite P. berghei. The ex vivo ookinete inhibitory concentration within mosquito gut IC50 was 150 nM. Cellular in vitro toxicity assays in the primary and immortalized human cell lines did not show cytotoxicity. A computational protein target identification pipeline identified a putative P. falciparum membrane protein (Pf3D7_1313500) involved in parasite calcium (Ca2+) homeostasis as a potential Calxinin target. This highly conserved protein is related to the family of transient receptor potential cation channels (TRP-ML). Target validation experiments showed that exposure of parasitized RBCs (pRBCs) to Calxinin induces a rapid release of intracellular Ca2+ from pRBCs; leaving de-calcinated parasites trapped in RBCs. Overall, we demonstrated that Calxinin is a promising antimalarial lead compound with a novel mechanism of action and with potential therapeutic, prophylactic, and transmission-blocking properties against parasites resistant to current antimalarials.

Methodology to streamline flow cytometric-based detection of early stage Plasmodium parasitemia in mice

Murine infection models are needed to develop therapeutics and vaccines to combat the Plasmodium parasites causing malaria. Herein, we describe an easy to perform flow cytometry-based methodology for detecting green fluorescent protein-expressing Plasmodium berghei in the peripheral red blood cells (RBC) of mice. This methodology uses one-step staining and simplified gating strategies to streamline the process of Plasmodium quantification and can detect parasitemia at an earlier time point after infection compared to traditional light microscopy-based techniques.

Similarly efficacious anti-malarial drugs SJ733 and pyronaridine differ in their ability to remove circulating parasites in mice

BackgroundArtemisinin-based combination therapy (ACT) has been a mainstay for malaria prevention and treatment. However, emergence of drug resistance has incentivised development of new drugs. Defining the kinetics with which circulating parasitized red blood cells (pRBC) are lost after drug treatment, referred to as the “parasite clearance curve”, has been critical for assessing drug efficacy; yet underlying mechanisms remain partly unresolved. The clearance curve may be shaped both by the rate at which drugs kill parasites, and the rate at which drug-affected parasites are removed from circulation.MethodsIn this context, two anti-malarials, SJ733, and an ACT partner drug, pyronaridine were compared against sodium artesunate in mice infected with Plasmodium berghei (strain ANKA). To measure each compound’s capacity for pRBC removal in vivo, flow cytometric monitoring of a single cohort of fluorescently-labelled pRBC was employed, and combined with ex vivo parasite culture to assess parasite maturation and replication.ResultsThese three compounds were found to be similarly efficacious in controlling established infection by reducing overall parasitaemia. While sodium artesunate acted relatively consistently across the life-stages, single-dose SJ733 elicited a biphasic effect, triggering rapid, partly phagocyte-dependent removal of trophozoites and schizonts, followed by arrest of residual ring-stages. In contrast, pyronaridine abrogated maturation of younger parasites, with less pronounced effects on mature parasites, while modestly increasing pRBC removal.ConclusionsAnti-malarials SJ733 and pyronaridine, though similarly efficacious in reducing overall parasitaemia in mice, differed markedly in their capacity to arrest replication and remove pRBC from circulation. Thus, similar parasite clearance curves can result for anti-malarials with distinct capacities to inhibit, kill and clear parasites.

Histological and Weight Changes in the Testes of Plasmodium Berghei- Infected Swiss Mice Treated with Chloroquine

Chloroquine has gained great emphasis in the treatment of malaria. This study sought experimentally to determine the histomorphological and weight changes in the testes of male mice infected with Plasmodium berghei and treated with chloroquine. The study used 30 Swiss mice divided into five groups. Group 1 is Control that was not infected with Plasmodium berghei and not treated with chloroquine as control, Group 2 is Plasmodium (Plasmodiul berghei) Infected animals but not treated, Group 3 is Plasmodium Infected animals + Chloroquine (5mg/kg), Group 4 is Plasmodium Infected animals + Chloroquine (10mg/kg) and Group 5 is Plasmodium Infected animals + Chloroquine (15mg/kg). The mice were treated for 7 days after parasitaemia was confirmed and the Group 2-5 testes studied with reference to Group 1. The results showed that the Group 2 showed a little distortion, difference in spermatogenic activities and increased cellular activities; Group 3 showed large, convoluted tubules, moderate number of spermatids and large interstitial spaces, Group 4 showed Large seminiferous tubules, large spermatids, increased distortion and group 5 showed shrinking of seminiferous tubules, degeneration of interstitial cells of Leydig cells and Sertolic cells with spermatids. Groups 1-5 showed no significant effect in in body weights and testes weights of Swiss mice. Plasmodium berghei (malaria) and chloroquine have effects on histomorphological structures of Swiss mice testes but not on their teste’s weights. The testicular section from Swiss mice infected with malaria and treated at various doses when compared with the Control (Group 1) showed some moderate distortion in some structures like seminiferous tubules, connective tissues between the tubules, lumen and interstitial spaces. It can be deducted that Plasmodium berghei which caused parasitaemia in mice could cause a little tissue effect on mice if not treated.

Influence of age and ways of treatment in the parasitemia in mice infected with Trypanosoma cruzi treated with high potency biotherapy

Introduction: The infection of mice by Trypanosoma cruzi is well known, making this a good model for understanding the effect of highly diluted medications. Mice of different ages show different responses to biotherapic T. cruzi [1]. Other data from our laboratory using biotherapic treatment at low potencies show that long lasting treatment has a better effect in mice infected with T. cruzi. However, the use of high potency biotherapics in mice of different ages infected with T. cruzi has not been analysed yet.
 
 Aim: To evaluate the effect of different ways of treatment using biotherapic 200 DH T. cruzi in the evolution of the curve of parasitemia of mice of different ages infected with T. cruzi.
 
 Materials and methods: A blind randomized controlled trial was performed using 107 swiss male mice, aged 28, 35 and 56 days, divided into groups: CONTROL(C) – mice aged 28(C28), 38(C38) and 56(C56) days, treated with 7% water-alcohol solution diluted with water (1mL/100mL); ONE DAY(OD) – mice aged 28(OD28), 38(OD38) and 56(OD56) days, treated with highly diluted medication 200 DH T. cruzi in a single dose, diluted in water (10mL/100mL); EVERY DAY(ED) – mice aged 28(ED28), 38(ED38) and 56(ED56) days, treated with highly diluted medication 200DH T.cruzi until the end of the experiment, diluted in water(1mL/100mL). Amber bottle was used and the water was changed every two days. The groups were infected with strain Y-T. cruzi, intraperitoneal,1400 blood trypomastigotes. Medicines were handled according to the Brazilian Homeopathic Pharmacopoeia [2], with microbiological testing according to RDC n° 67 and in vivo biological risk. We compared the parasitemia curve and total parasitemia, determined daily counting of the parasites [3], obtained using the tests Kruskal-Wallis and Wald-Wolfowitz, Statistica 8.0, 5% significance. Approved by the Ethics Committee for Animal Experimentation/ UEM - 030/2008.
 
 Results: The animal age and the ways of treatment used influenced the evolution of the parasitemia curve. This evolution was different among different ages, and the youngest mice of the control group had higher averages of parasitemia ( C28=1.4x106/mL; C38= 1.3 x106/mL and C56=1.0x106/mL ) (fig1). This evolution was not observed in the groups treated daily, in which 56 day-old mice presented a higher parasitemia compared to the other groups ( ED28= 1.3x106/mL; ED38=0.9x106/mL and ED56=1.2x106/mL )(fig1b).
 
 For animals treated with a single dose, the energetic stimulus provided by biotherapic caused homogeneity of biological behavior, with significant elevation of parasitemia ( OD28=1.8x106/mL; OD38=1.3x106/mL and OD56=1.5 x106/mL) (fig1c). Likewise, the single dose treatment invariably resulted in an increase of parasitemia when compared to other treatments within the same age group (fig1d-f). The treatment performed daily in animals aged 28 and 38 days showed a decrease in parasitemia (fig1d-f). For 56 day-old mice this fall was not observed (fig1f). The meaning of this finding should be better explored considering the physiological maturity versus the vital energy of mice of different ages.
 
 Conclusion: The age and the ways of treatment used are important factors to be considered when using a highly diluted medication. The clinical use of these results in humans, should take into consideration the allometric system of medication dosage which takes into account the metabolic rate of each organism.

Causticum hahnemanni, Conium maculatum and Lycopodium clavatum highly diluted medications decreases parasitemia in mice infected by Trypanosoma cruzi

Introduction: Benznidazole is the only medicine available in Brazil for Chagas’ disease treatment, however it presents low efficacy in the chronic phase and several adverse effects [1-3].
 Aim: Evaluate the effect of Causticum hahnemanni, Conium maculatum and Lycopodium clavatum [4-6] administered to mice infected with T. cruzi.
 Method: In blind randomized controlled trial 42 male Swiss mice, 8 weeks of age, have been grouped: GCaus –treated with C. hahnemanni 13cH (n=10), GCon –treated with C. maculatum 13 cH (n=11), GLy –treated with L. clavatum13cH (n=10) and CG – control group (n=11) treated with 7% hydro alcoholic solution 13cH. The animals were infected intraperitoneally with 1.400 blood trypomastigotes of T. cruzi - Y strain. Medications were been prepared according to Brazilian Homeopathic Pharmacopoeia [7]. Medication was diluted in water (1mL/100mL) offered ad libitum, from amber recipient during 16 hours administered 48 hours before infection and 48, 96 and 144 hours after inoculation. Parasitological parameters assessed: total parasitemia (TP), maximum peak of parasites (MPP), pre-patent period (PPP) and area under curve (AUC). Parasitemia was evaluated daily counting from the first day of infection. Clinical parameters assessed: weight, temperature, water and food intake and excreta were measured counting from the 5º day before infection until animals’ death or checking negative parasitemia for 3 consecutive days. Mortality was registered for 75 days after infection. Ethics Committee for Experiments in Animals gave approval UEM 054/11. Statistical comparison of data was performed with Kruskal-Wallis test, with 5% significance.
 Results and Discussion: The diluted medications have been significantly reduced the parasitological parameters: MPP (p

Procainamide-SAHA Fused Inhibitors of hHDAC6 Tackle Multidrug-Resistant Malaria Parasites.

Epigenetic post-translational modifications are essential for human malaria parasite survival and progression through its life cycle. Here, we present new functionalized suberoylanilide hydroxamic acid (SAHA) derivatives that chemically combine the pan-histone deacetylase inhibitor SAHA with the DNA methyltransferase inhibitor procainamide. A three- or four-step chemical synthesis was designed starting from cheap raw materials. Compared to the single drugs, the combined molecules showed a superior activity in Plasmodium and a potent inhibition against human HDAC6, exerting no cytotoxicity in human cell lines. These new compounds are fully active in multidrug-resistant Plasmodium falciparum Cambodian isolates. They target transmission of the parasite by inducing irreversible morphological changes in gametocytes and inhibiting exflagellation. The compounds are slow-acting and have an additive antimalarial effect in combination with fast-acting epidrugs and dihydroartemisinin. The lead compound decreases parasitemia in mice in a severe malaria model. Taken together, this novel fused molecule offers an affordable alternative to current failing antimalarial therapy.

Evolution of protective human antibodies against Plasmodium falciparum circumsporozoite protein repeat motifs.

The circumsporozoite protein of the human malaria parasite Plasmodium falciparum (PfCSP) is the main target of antibodies that prevent the infection and disease, as shown in animal models. However, the limited efficacy of the PfCSP-based vaccine RTS,S calls for a better understanding of the mechanisms driving the development of the most potent human PfCSP antibodies and identification of their target epitopes. By characterizing 200 human monoclonal PfCSP antibodies induced by sporozoite immunization, we establish that the most potent antibodies bind around a conserved (N/D)PNANPN(V/A) core. High antibody affinity to the core correlates with protection from parasitemia in mice and evolves around the recognition of NANP motifs. The data suggest that the rational design of a next-generation PfCSP vaccine that elicits high-affinity antibody responses against the core epitope will promote the induction of protective humoral immune responses.

Effect of After-Treatment of Strychnos ligustrina Extract on The Percentage of Parasitemia in Mice Infected with Plasmodium berghei

Antimalarial treatment is usually given up to 4 days which reduces the number of parasitemia, but malaria can still occur. Therefore, a study to determine the percentage of parasitemia after drug administration is important. Strychnos ligustrina has been investigated in vitro to inhibit the growth of Plasmodium berghei and reduced the number of parasitemia during 4 days of treatment. The purpose of this study was to determine the percentage of parasitemia in mice infected with P. berghei after 4 day treatments with S. ligustrina extract. S. ligustrina was extracted by maceration method using Ethanol 25%, 50%, and 75% (E25, E50, E75, respectively), and Aquades (EA). This study used 91 male mice divided into 5 groups: E25, E50, E70, EA, each extract consisted of 3 doses (200, 400 and 800 mg/kg BW) and Drug Control (DC). For Drug Control (DC) was using a combination of Dihy-droartemisin dose 25 mg/kg BW and piperaquine phosphate dose 197 mg/kg BW. Mice infected with 1x 106 P. berghei intraperitoneally. Blood samples were taken on day 5 after treatment with S. ligustrina extract for 8 days (days 1-8 after treatment). Preparation of blood smear was stained with Giemsa to calculate the percentage of parasitemia by counting the number of infected erythrocytes divided by 500 erythrocytes and multiplied by 100%. The percentages of parasitemia day 7 with 3 kinds of doses of 200, 400, 800 mg/kg body weight in E25 (11,54%, 2.60% and 11.54%, respectively), in E50 (3.44%, 0%, 3.81%, respectively), in E75 (19.25%, 0.73 %, 9.75 %, respectively), in EA (0.77%, 4.48%, 8.67%, respectively) and in DC 2.10%. At the stage of schizogony, which is one of the life cycles of malaria found in the liver, this parasite is not visible in the blood circulation. The results showed that P. berghei was still found in the blood of mice after administration of S. ligustrina extracts up to 4 days in all treatments with different percentages of parasitemia. Based on these results it is recommended that the administration of drugs with S. ligustrina extract as antimalarial drugs for more than 4 days.

In Vitro and In Vivo Antimalarial Activities and Toxicological Assessment of Pogostemon Cablin (Blanco) Benth.

The aim of this study was to investigate the antimalarial activities and toxicity of Pogostemon cablin extracts. In vitro activities against the chloroquine-resistant Plasmodium falciparum K1 strain were assessed by using the Plasmodium lactate dehydrogenase enzyme (pLDH) assay, while in vivo activity against the Plasmodium berghei ANKA strain in mice was investigated using a 4-day suppressive test. The in vitro and in vivo toxicity were determined in Vero cells and mice, respectively. The ethanolic extract possessed antimalarial activity with an IC50 of 24.49 ± 0.01 µg/ml, whereas the aqueous extract showed an IC50 of 549.30 ± 0.07 µg/ml. Cytotoxic analyses of the ethanolic and aqueous extracts revealed a nontoxic effect on Vero cells at a concentration of 80 µg/ml. Based on a preliminary study of in vitro antimalarial activity, the ethanolic extract was chosen as a potential agent for further in vivo antimalarial activity analysis in mice. The ethanolic extract, which showed no toxic effect on mice at a dose of 2000 mg/kg body weight, significantly suppressed parasitemia in mice by 38.41%, 45.12% and 89.00% at doses of 200, 400 and 600 mg/kg body weight, respectively. In conclusion, this study shows that the ethanolic P. cablin extract possesses in vitro and in vivo antimalarial activity without toxic effects.

Protozoan Parasite Babesia microti Subverts Adaptive Immunity and Enhances Lyme Disease Severity.

Lyme disease is the most prominent tick-borne disease in the United States. Co-infections with the tick-transmitted pathogens Babesia microti and Borrelia burgdorferi sensu stricto are becoming a serious health problem. B. burgdorferi is an extracellular spirochete that causes Lyme disease while B. microti is a protozoan that infects erythrocytes and causes babesiosis. Testing of donated blood for Babesia species is not currently mandatory due to unavailability of an FDA approved test. Transmission of this protozoan by blood transfusion often results in high morbidity and mortality in recipients. Infection of C3H/HeJ mice with B. burgdorferi and B. microti individually results in inflammatory Lyme disease and display of human babesiosis-like symptoms, respectively. Here we use this mouse model to provide a detailed investigation of the reciprocal influence of the two pathogens on each other during co-infection. We show that B. burgdorferi infection attenuates parasitemia in mice while B. microti subverts the splenic immune response, such that a marked decrease in splenic B and T cells, reduction in antibody levels and diminished functional humoral immunity, as determined by spirochete opsonophagocytosis, are observed in co-infected mice compared to only B. burgdorferi infected mice. Furthermore, immunosuppression by B. microti in co-infected mice showed an association with enhanced Lyme disease manifestations. This study demonstrates the effect of only simultaneous infection by B. burgdorferi and B. microti on each pathogen, immune response and on disease manifestations with respect to infection by the spirochete and the parasite. In our future studies, we will examine the overall effects of sequential infection by these pathogens on host immune responses and disease outcomes.