Plasmodium falciparum neonatal malaria with atypical presentation: a case series from southwestern Ethiopia.

BACKGROUND: Neonatal malaria is defined as the detection of asexual stages of Plasmodium species in the cord blood within the first 28 days of life. It can be congenital or acquired through mosquito bites or blood transfusions. Neonates are generally considered to be relatively protected due to the multiple innate and acquired physiological protective effects present in neonates. However, in areas where malaria is endemic, the prevalence of malaria in neonates is high. The predominant clinical feature of malaria in neonates is fever. Other clinical manifestations of neonatal malaria include respiratory distress, pallor and anaemia, hepatomegaly, refusal to feed, jaundice and diarrhoea. Atypical presentations without fever can lead to inaccurate diagnosis and contribute to neonatal morbidity and mortality. Neonates from endemic areas with any of the above symptoms should be screened for malaria. CASE PRESENTATION: We present a series of three cases of neonatal Plasmodium falciparum malaria that presented atypically without febrile episodes and were diagnosed and managed at Mizan-Tepi University Teaching Hospital between July and September 2023. The first patient presented with vomiting, refusal to feed, pallor, severe anaemia, and splenomegaly. The second patient presented with an inconsolable cry, failure to pass feces, abdominal distention, and anaemia. The third patient presented with vomiting and anaemia. All patients received a 7-day course of intravenous artesunate; the first patient also received a blood transfusion. All patients recovered and were discharged. CONCLUSIONS: Partial immunity resulting from repeated malaria infections in endemic regions may result in the transfer of high levels of maternal Immunoglobulin G (IgG) antibodies through the placenta and can produce different atypical clinical presentations. In malaria-endemic areas, neonates presenting with any of the presenting signs and symptoms of malaria, including afebrile presentation, require malaria screening to avoid delays in diagnosis.

Late Parasitological Failure and Subsequent Isolated Gametocytemia of Uncomplicated Plasmodium falciparum Malaria in a Returned Traveler From Ghana, 2023.

Herein, we report a case of uncomplicated falciparum malaria with late parasitological failure in a 45-year-old businessman returning from Ghana. The patient visited the emergency department with high fever, headache, and dizziness. He traveled without antimalarial chemoprophylaxis. Laboratory tests led to the diagnosis of uncomplicated falciparum malaria with an initial density of 37,669 parasites per µL of blood (p/µL). The patient was treated with intravenous artesunate followed by atovaquone/proguanil. He was discharged with improved condition and decreased parasite density of 887 p/µL. However, at follow-up, parasite density increased to 7,630 p/µL despite the absence of any symptoms. Suspecting treatment failure, the patient was administered intravenous artesunate and doxycycline for seven days and then artemether/lumefantrine for three days. Blood smear was negative for asexual parasitemia after re-treatment but positive for gametocytemia until day 101 from the initial diagnosis. Overall, this case highlights the risk of late parasitological failure in patients with imported uncomplicated falciparum malaria.

Exchange transfusion combined with artesunate (ET-AS) as a safe and effective therapy in severe P. falciparum malaria: a case series.

BACKGROUND: the mortality associated with severe malaria due to Plasmodiun falciparum remains high despite improvements in malaria management. Case prensentation: this case series aims to describe the efficacy and safety of the exchange transfusion combined with artesunate (ET-AS) regimen in severe P. falciparum malaria. Eight patients diagnosed with severe P. falciparum malaria were included. All patients underwent ET using the COBE Spectra system. The aimed for a post-exchange hematocrit of 30%. Half the estimated blood volume was removed and replaced using fresh frozen plasma. The regimen was well-tolerated without complications. The parasite clearance time ranged from 1 ~ 5 days. Five patients with cerebral malaria exhibited full improved consciousness within 3 days, while patient2 with hemolysis improved on day 2. Liver function improved within 1 ~ 6 days, and patient 1 and patient 6 showed improvements renal function on days 18 and 19, respectively. The length of intensive care unit stay range from 2 ~ 10 days, and all patients treated with ET-AS remained in the hospital for 3 ~ 19 days. CONCLUSIONS: these preliminary results suggest that ET-AS regimens are a safe and effective therapy for severe P. falciparum malaria and can benefit patients in clinical settings.

Development, characterization, and evaluation of withaferin-A and artesunate-loaded pH-responsive acetal-dextran polymeric nanoparticles for the management of malaria.

Artemisinin and its derivatives have been commonly used to treat malaria. However, the emergence of resistance against artemisinin derivatives has posed a critical challenge in malaria management. In the present study, we have proposed a combinatorial approach, utilizing pH-responsive acetal-dextran nanoparticles (Ac-Dex NPs) as carriers for the delivery of withaferin-A (WS-3) and artesunate (Art) to improve treatment efficacy of malaria. The optimized WS-3 and Art Ac-Dex NPs demonstrated enhanced pH-responsive release profiles under parasitophorous mimetic conditions (pH 5.5). Computational molecular modeling reveals that Ac-Dex's polymeric backbone strongly interacts with merozoite surface protein-1 (MSP-1), preventing erythrocyte invasion. In-vitro antimalarial activity of drug-loaded Ac-Dex NPs reveals a 1-1.5-fold reduction in IC50 values compared to pure drug against the 3D7 strain of Plasmodium falciparum. Treatment with WS-3 Ac-Dex NPs (100 mg/kg) and Art Ac-Dex NPs (30 mg/kg) to Plasmodium berghei-infected mice resulted in 78.11 % and 100 % inhibition of parasitemia. Notably, the combination therapy comprised of Art and WS-3 Ac-Dex NPs achieved complete inhibition of parasitemia even at a half dose of Art, indicating the synergistic potential of the combinations. However, further investigations are necessary to confirm the safety and effectiveness of WS-3 and Art Ac-Dex NPs for their successful clinical implications.

The human malaria-Aotus monkey model: a historical perspective in antimalarial chemotherapy research at the Gorgas Memorial Laboratory-Panama.

The human malaria-Aotus monkey model has served the malaria research community since its inception in 1966 at the Gorgas Memorial Laboratory (GML) in Panama. Spanning over five decades, this model has been instrumental in evaluating the in vivo efficacy and pharmacokinetics of a wide array of candidate antimalarial drugs, whether used singly or in combination. The animal model could be infected with drug-resistant and susceptible Plasmodium falciparum and Plasmodium vivax strains that follow a characteristic and reproducible course of infection, remarkably like human untreated and treated infections. Over the years, the model has enabled the evaluation of several synthetic and semisynthetic endoperoxides, for instance, artelinic acid, artesunate, artemether, arteether, and artemisone. These compounds have been evaluated alone and in combination with long-acting partner drugs, commonly referred to as artemisinin-based combination therapies, which are recommended as first-line treatment against uncomplicated malaria. Further, the model has also supported the evaluation of the primaquine analog tafenoquine against blood stages of P. vivax, contributing to its progression to clinical trials and eventual approval. Besides, the P. falciparum/Aotus model at GML has also played a pivotal role in exploring the biology, immunology, and pathogenesis of malaria and in the characterization of drug-resistant P. falciparum and P. vivax strains. This minireview offers a historical overview of the most significant contributions made by the Panamanian owl monkey (Aotus lemurinus lemurinus) to malaria chemotherapy research.

Efficacy and safety of single-dose artesunate plus sulfalene/pyrimethamine combined with praziquantel for the treatment of children with Schistosoma mansoni or Schistosoma haematobium in western Kenya: a randomised, open-label controlled trial.

BACKGROUND: Reliance on praziquantel for the treatment and control of schistosomiasis is likely to facilitate the emergence of drug resistance. Combination therapy targeting adult and juvenile schistosome worms is urgently needed to improve praziquantel efficacy and delay the potential development of drug resistance. We assessed the efficacy and safety of single-dose praziquantel combined with single-dose artesunate plus sulfalene-pyrimethamine in the treatment of Kenyan children with schistosomiasis. METHODS: This was an open-label, randomised clinical trial involving 426 school-aged children (7-15 years old) diagnosed with Schistosoma mansoni (by Kato-Katz) or S. haematobium (by urine filtration). They were randomly assigned (1:1:1) to receive a single dose of praziquantel (40 mg/kg), a single dose of artesunate plus sulfalene-pyrimethamine (12 mg/kg artesunate) or combination therapy using a single dose of praziquantel (40 mg/kg) combined with a single dose of artesunate plus sulfalene-pyrimethamine (12 mg/kg artesunate). The primary outcome was cure and egg reduction rates at 6 weeks post-treatment in the available case population. Adverse events were assessed within 3 h after treatment. RESULTS: Of the 426 children enrolled, 135 received praziquantel, 150 received artesunate plus sulfalene-pyrimethamine, and 141 received combination therapy. Outcome data were available for 348 (81.7%) children. For S. mansoni-infected children (n = 335), the cure rates were 75.6%, 60.7%, and 77.8%, and the egg reduction rates were 80.1%, 85.0%, and 88.4% for praziquantel, artesunate plus sulfalene-pyrimethamine, and combination therapy, respectively. For S. haematobium-infected children (n = 145), the corresponding cure rates were 81.4%, 71.1%, and 82.2%, and the egg reduction rates were 95.6%, 97.1%, and 97.7%, respectively. Seventy-one (16.7%) children reported mild-intensity adverse events. The drugs were well tolerated and no serious adverse events were reported. CONCLUSIONS: A single oral dose of praziquantel combined with artesunate plus sulfalene-pyrimethamine cured a high proportion of children with S. haematobium but did not significantly improve the treatment efficacy for either urinary or intestinal schistosomiasis. Sequential administration of praziquantel and artesunate plus sulfalene-pyrimethamine may enhance the efficacy and safety outcomes.

Artesunate attenuates isoprenaline induced cardiac hypertrophy in rats via SIRT1 inhibiting NF-κB activation.

Cardiac Hypertrophy is an adaptive response of the body to physiological and pathological stimuli, which increases cardiomyocyte size, thickening of cardiac muscles and progresses to heart failure. Downregulation of SIRT1 in cardiomyocytes has been linked with the pathogenesis of cardiac hypertrophy. The present study aimed to investigate the effect of Artesunate against isoprenaline induced cardiac hypertrophy in rats via SIRT1 inhibiting NF-κB activation. Experimental cardiac hypertrophy was induced in rats by subcutaneous administration of isoprenaline (5 mg/kg) for 14 days. Artesunate was administered simultaneously for 14 days at a dose of 25 mg/kg and 50 mg/kg. Artesunate administration showed significant dose dependent attenuation in mean arterial pressure, electrocardiogram, hypertrophy index and left ventricular wall thickness compared to the disease control group. It also alleviated cardiac injury biomarkers and oxidative stress. Histological observation showed amelioration of tissue injury in the artesunate treated groups compared to the disease control group. Further, artesunate treatment increased SIRT1 expression and decreased NF-kB expression in the heart. The results of the study show the cardioprotective effect of artesunate via SIRT1 inhibiting NF-κB activation in cardiomyocytes.

Harnessing cholesterol uptake of malaria parasites for therapeutic applications.

Parasites, such as the malaria parasite P. falciparum, are critically dependent on host nutrients. Interference with nutrient uptake can lead to parasite death and, therefore, serve as a successful treatment strategy. P. falciparum parasites cannot synthesise cholesterol, and instead source this lipid from the host. Here, we tested whether cholesterol uptake pathways could be 'hijacked' for optimal drug delivery to the intracellular parasite. We found that fluorescent cholesterol analogues were delivered from the extracellular environment to the intracellular parasite. We investigated the uptake and inhibitory effects of conjugate compounds, where proven antimalarial drugs (primaquine and artesunate) were attached to steroids that mimic the structure of cholesterol. These conjugated antimalarial drugs improved the inhibitory effects against multiple parasite lifecycle stages, multiple parasite species, and drug-resistant parasites, whilst also lowering the toxicity to human host cells. Steroids with introduced peroxides also displayed antimalarial activity. These results provide a proof-of-concept that cholesterol mimics can be developed as a drug delivery system against apicomplexan parasites with the potential to improve drug efficacy, increase therapeutic index, and defeat drug resistance.

Antitumour effects of artesunate via cell cycle checkpoint controls in human oesophageal squamous carcinoma cells.

Artesunate (ART), an effective antimalarial semisynthetic derivative of artemisinin, exhibits antitumour properties, but the mechanism(s) involved remain elusive. In this study, we investigated the antitumour effects of ART on human oesophageal squamous cell carcinoma (ESCC) cell lines. Treatment of ESCC cell lines with ART resulted in the production of excessive reactive oxygen species (ROS) that induced DNA damage, reduced cell proliferation and inhibited clonogenicity via G1-S cell cycle arrest and/or apoptosis in vitro. The administration of ART to nude mice with ESCC cell xenografts inhibited tumour formation in vivo. However, the cytotoxicity of ART strongly differed among the ESCC cell lines tested. Transcriptomic profiling revealed that although the expression of large numbers of genes in ESCC cell lines was affected by ART treatment, these genes could be functionally clustered into pathways involved in regulating cell cycle progression, DNA metabolism and apoptosis. We revealed that p53 and Cdk4/6-p16-Rb cell cycle checkpoint controls were critical determinants required for mediating ART cytotoxicity in ESCC cell lines. Specifically, KYSE30 cells with p53Mut/p16Mut were the most sensitive to ART, KYSE150 and KYSE180 cells with p53Mut/p16Nor exhibited intermediate responses to ART, and Eca109 cells with p53Nor/p16Nor exhibited the most resistance to ATR. Consistently, perturbation of p53 expression using RNA interference (RNAi) and/or Cdk4/6 activity using the inhibitor palbociclib altered ART cytotoxicity in KYSE30 cells. Given that the p53 and Cdk4/6-cyclin D1-p16-Rb genes are commonly mutated in ESCC, our results potentially shed new light on neoadjuvant chemotherapy strategies for ESCC.

Exploring the neuroprotective role of artesunate in mouse models of anti-NMDAR encephalitis: insights from molecular mechanisms and transmission electron microscopy.

BACKGROUND: The pathway involving PTEN-induced putative kinase 1 (PINK1) and PARKIN plays a crucial role in mitophagy, a process activated by artesunate (ART). We propose that patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis exhibit insufficient mitophagy, and ART enhances mitophagy via the PINK1/PARKIN pathway, thereby providing neuroprotection. METHODS: Adult female mice aged 8-10 weeks were selected to create a passive transfer model of anti-NMDAR encephalitis. We conducted behavioral tests on these mice within a set timeframe. Techniques such as immunohistochemistry, immunofluorescence, and western blotting were employed to assess markers including PINK1, PARKIN, LC3B, p62, caspase3, and cleaved caspase3. The TUNEL assay was utilized to detect neuronal apoptosis, while transmission electron microscopy (TEM) was used to examine mitochondrial autophagosomes. Primary hippocampal neurons were cultured, treated, and then analyzed through immunofluorescence for mtDNA, mtROS, TMRM. RESULTS: In comparison to the control group, mitophagy levels in the experimental group were not significantly altered, yet there was a notable increase in apoptotic neurons. Furthermore, markers indicative of mitochondrial leakage and damage were found to be elevated in the experimental group compared to the control group, but these markers showed improvement following ART treatment. ART was effective in activating the PINK1/PARKIN pathway, enhancing mitophagy, and diminishing neuronal apoptosis. Behavioral assessments revealed that ART ameliorated symptoms in mice with anti-NMDAR encephalitis in the passive transfer model (PTM). The knockdown of PINK1 led to a reduction in mitophagy levels, and subsequent ART intervention did not alleviate symptoms in the anti-NMDAR encephalitis PTM mice, indicating that ART's therapeutic efficacy is mediated through the activation of the PINK1/PARKIN pathway. CONCLUSIONS: At the onset of anti-NMDAR encephalitis, mitochondrial damage is observed; however, this damage is mitigated by the activation of mitophagy via the PINK1/PARKIN pathway. This regulatory feedback mechanism facilitates the removal of damaged mitochondria, prevents neuronal apoptosis, and consequently safeguards neural tissue. ART activates the PINK1/PARKIN pathway to enhance mitophagy, thereby exerting neuroprotective effects and may achieve therapeutic goals in treating anti-NMDAR encephalitis.

Novel artesunate and isatin hybrid CT3-1 suppresses collagen-induced arthritis through abrogating dendritic cell chemotaxis-induced by CCR5.

BACKGROUND: Chemotaxis and trafficking of dendritic cells (DCs) induced by cytokine receptors are crucial steps in rheumatoid arthritis (RA) pathogenesis. C-C chemokine receptor type 5 (CCR5) plays a key role in DC movement and has been implicated in multitudinous inflammatory and immunology diseases. Thus, targeting CCR5 to suppress DC chemotaxis is considered as a potential strategy for the management of RA. METHODS: Herein, we first synthesized a new hybrid named CT3-1 which based on artesunate and isatin. Besides, we studied the regulating effectiveness of CT3-1 on bone marrow-derived DCs (BMDCs) and on collagen-induced arthritis (CIA) through RNA-seq analysis, cell function experiments in vitro and mice model in vivo. RESULTS: The results shown that CT3-1 mainly reduced CCR5 expression of immature BMDCs and importantly inhibited immature BMDC migration induced by CCR5 in vitro, with no or minor influence on other functions of DCs, such as phagocytosis and maturation. In the mouse model, CT3-1 relieved arthritis severity and inhibited CIA development. Furthermore, CT3-1 intervention decreased the expression of CCR5 in DCs and reduced the proportion of DCs in the peripheral blood of CIA mice. CONCLUSIONS: Our findings suggest that CCR5-induced chemotaxis and trafficking of immature DCs are important in RA. Targeting CCR5 and inhibiting immature DC chemotaxis may provide a novel choice for the treatment of RA and other similar autoimmune diseases. Moreover, we synthesized a new hybrid compound CT3-1 that could inhibit immature DC trafficking and effectively relieve RA by directly reducing the CCR5 expression of immature DCs.

Exploring pectin-casein micelles as novel carriers for oral drug delivery of artesunate in the treatment of systemic lupus erythematosus.

The oral route of administration is considered the optimal choice for treating chronic diseases due to its convenience and non-invasiveness, which can help prevent physical and mental harm to patients undergoing long-term treatment. However, challenges such as safety, gastrointestinal stability, and bioavailability of oral drugs often limit their effectiveness. Natural biomacromolecule micelles, known for their safety, stability, biocompatibility, and diverse functions, have emerged as promising carriers for oral treatment of chronic diseases like systemic lupus erythematosus (SLE) with fat-soluble drugs. This study introduces an innovative approach by developing an oral delivery system using chemically synthesized natural biomacromolecules to load artesunate for treating SLE. By synthesizing amphiphilic polymer micelles from pectin and casein through a carbodiimide reaction, a more stable structure is achieved. The hydrophobic core of these micelles encapsulates artesunate, resulting in the formation of an oral delivery system (PC-AS) with several advantages, including high drug loading and encapsulation efficiency, small particle size, negative potential, strong stability in the gastrointestinal tract, low toxicity and side effects, strong adhesion in the small intestine, and high bioavailability. These advantages facilitate efficient absorption of artesunate in the gastrointestinal tract, leading to improved bioavailability and effective alleviation of SLE-like symptoms in MRL/lpr mice. By utilizing chemically synthesized natural macromolecular micelles for delivering artesunate in the treatment of SLE, this study overcomes the oral barriers associated with the original drug and presents a novel solution for the long-term oral treatment of chronic diseases.

Lacrimal gland Alterations and the Effect of artesunate on experimental induced diabetes rat models and related mechanisms.

Diabetic patients are at high risk of developing lacrimal gland dysfunction, and the antimalarial drug artesunate (ART) was recently used to induce experimental-induced diabetes mellitus. This study's objective is to investigate the lacrimal gland alteration and the effect of ART on experimentally induced diabetes rat models and its related mechanisms. Forty rats were divided into five groups (8 rats/group): healthy control group (HC), diabetic group (DM), 50 mg/kg ART intervention diabetic group [DM + ART (50 mg/kg)], 100 mg/kg ART intervention diabetic group [DM + ART (100 mg/kg)] and 6 U/kg Insulin intervention diabetic group (DM + INS). The morphology of the eyeball and lacrimal gland tissues was determined using hematoxylin and eosin staining. In addition, external lacrimal glands were harvested for electronic microscopic examination, NFκB1, and TNF-α protein expression evaluation by immunohistochemistry and mRNA expression analysis by RT-PCR. Histopathological and ultrastructural changes suggest ART intervention has an improved structural effect. Protein expression of NFκB1 in the DM + ART (100 mg/kg) group was decreased. TNF-α significantly decreased in the DM + ART (50 mg/kg) and insulin groups. We concluded that ART improves structural changes in a lacrimal gland in diabetic rats. The present study provides further evidence of the therapeutic effect of ART on the lacrimal gland of diabetic rats by decreasing the expression of NFκB1 and TNF-α.

A severe case of Plasmodium falciparum malaria in a traveler returning from Kazakhstan, a malaria-free country.

Following a 2-week trip to Kazakhstan, a 42-year-old woman presented at the emergency department in Germany with fever, headache, nausea, and neurological symptoms. An infection with Plasmodium falciparum was rapidly diagnosed. The patient was immediately treated with intravenous artesunate and transferred to an intensive care unit. The initial parasite density was as high as 30% infected erythrocytes with 845,880 parasites/µL. Since Kazakhstan was declared malaria-free in 2012, molecular testing for Plasmodium has been initiated to identify a possible origin. Genotyping of the msp-1 gene and microsatellite markers showed that the parasites are of African origin, with two different alleles indicating a polyclonal infection. After a hospitalization of 10 days, the patient was discharged in good health. Overall, our results emphasize that malaria must be on the list of differential diagnoses for patients with fever of unknown origin, even if they come from countries where malaria does not commonly occur.

[Gastrointestinal symptoms may reflect complicated falciparum malaria]. / Gastrointestinale Symptome als Ausdruck einer komplizierten Malaria tropica.

HISTORY: A 42-year-old female presented with a two-day history of vomiting, diarrhea, fever and chills. Two weeks before she had returned to Germany from a Safari in Tanzania. She had disregarded the recommendation to take antimalarial chemoprophylaxis. CLINICAL FINDINGS AND DIAGNOSIS: The thin blood film showed Plasmodium falciparum-parasitized erythrocytes, and Plasmodium falciparum malaria was diagnosed. The full blood count showed thrombocytopenia and ultrasound imaging revealed splenomegaly. Initially the criteria for complicated malaria were not fulfilled. THERAPY AND COURSE: We started oral therapy with atovaquone/proguanil. The patient vomited the tablets twice. Therefore therapy was switched to intravenous artesunate. Subsequently, parasitemia dropped from 2.8 to 1.0 % within 22 hours. After 3 days of artesunate i. v., treatment could then be completed with oral atovaquone/proguanil, and the symptoms resolved. CONCLUSIONS: Patients with malaria and persistent vomiting should be treated intravenously and monitored closely, as severe gastrointestinal symptoms may reflect impending organ failure. We therefore propose including persistent vomiting in the list of criteria for complicated malaria.

Artesunate-loaded thermosensitive chitosan hydrogel promotes osteogenesis of maxillary tooth extraction through regulating T lymphocytes in type 2 diabetic rats.

BACKGROUND: Type 2 diabetes mellitus (T2DM) causes severe bone loss after tooth extraction as a hyperglycemic environment causes aberrant bone homeostasis. Artesunate (ART) is known to possess anti-inflammation and osteogenic properties. However, its osteogenesis property in alveolar bone remains unclear. This study aimed to explore the osteogenic and immunoregulatory effects of artesunate-loaded thermosensitive chitosan hydrogel (ART-loaded TCH) on maxilla tooth extraction in T2DM rats. METHODS: T2DM rats were induced by a high-fat diet and streptozotocin. Different concentrations of ART-loaded TCH were applied in tooth extraction sockets. Bone loss and the expression of osteogenic regulatory factors (OPG, ALP, RANK) were evaluated. The immunoregulatory effects of ART-loaded TCH were observed through detecting the infiltration of T lymphocytes and their cytokines. The underlying mechanisms were explored. RESULTS: Results showed that the 150 mg/ml ART-loaded TCH group significantly ameliorated maxilla bone height and bone mineral density when compared with the T2DM group (p < 0.05). It also improved the expression of OPG, ALP, and RANK. Although the alteration of CD4+ T, CD8+ T, and CD4+:CD8+ T ratio has no significant difference among groups, the release of Th1 and Th2 in the 150 mg/ml ART-loaded TCH group has been significantly regulated than in the T2DM group (p < 0.05). Besides, ART-loaded TCH treatment inhibited the expression of p38 MAPK and ERK1 in T2DM maxilla. CONCLUSIONS: Therefore, the results indicated that 150 mg/ml ART-loaded TCH could be an effective method to prevent bone loss in T2DM tooth extraction rats by modulating the immunoregulation of Th1 and Th2 and the MAPK signaling pathway.

Whole genome sequencing identifies novel mutations in malaria parasites resistant to artesunate (ATN) and to ATN + mefloquine combination.

Introduction: The global evolution of resistance to Artemisinin-based Combination Therapies (ACTs) by malaria parasites, will severely undermine our ability to control this devastating disease. Methods: Here, we have used whole genome sequencing to characterize the genetic variation in the experimentally evolved Plasmodium chabaudi parasite clone AS-ATNMF1, which is resistant to artesunate + mefloquine. Results and discussion: Five novel single nucleotide polymorphisms (SNPs) were identified, one of which was a previously undescribed E738K mutation in a 26S proteasome subunit that was selected for under artesunate pressure (in AS-ATN) and retained in AS-ATNMF1. The wild type and mutated three-dimensional (3D) structure models and molecular dynamics simulations of the P. falciparum 26S proteasome subunit Rpn2 suggested that the E738K mutation could change the toroidal proteasome/cyclosome domain organization and change the recognition of ubiquitinated proteins. The mutation in the 26S proteasome subunit may therefore contribute to altering oxidation-dependent ubiquitination of the MDR-1 and/or K13 proteins and/or other targets, resulting in changes in protein turnover. In light of the alarming increase in resistance to artemisin derivatives and ACT partner drugs in natural parasite populations, our results shed new light on the biology of resistance and provide information on novel molecular markers of resistance that may be tested (and potentially validated) in the field.

Efficacy of a Single Oral Dose of Artesunate plus Sulfalene-Pyrimethamineversus Praziquantel in the Treatment of Schistosoma mansoni in Kenyan Children: An Open-Label, Randomized, Exploratory Trial.

Unlike praziquantel, artemisinin derivatives are effective against juvenile schistosome worms. We assessed the efficacy and safety of a single oral dose of artesunate plus sulfalene-pyrimethamine versus praziquantel in the treatment of Schistosoma mansoni. Seventy-three schoolchildren (aged 9-15 years) with confirmed S. mansoni infection in Rarieda, western Kenya, were randomly assigned to receive either a single oral dose of artesunate plus sulfalene-pyrimethamine (n = 39) or a single dose of praziquantel (n = 34). The cure and egg reduction rates at 4 weeks posttreatment were 69.4% (25/36) versus 80.6% (25/31) (P = 0.297) and 99.1% versus 97.5% (P = 0.607) in the artesunate plus sulfalene-pyrimethamine group versus praziquantel group, respectively. Fourteen children developed adverse events, and there were no serious adverse events. A single oral dose of artesunate plus sulfalene-pyrimethamine has efficacy comparable to that of praziquantel in the treatment of S. mansoni, but these results should be confirmed in larger randomized controlled trials.

Inhibition of keloid fibroblast proliferation by artesunate is mediated by targeting the IRE1α/XBP1 signaling pathway and decreasing TGF-ß1.

BACKGROUND: Keloid is a benign hyperplastic dermatosis with high recurrence rate and complex pathogenesis. There is no universally effective treatment yet. New therapies and elucidation of pathogenesis are urgently required. AIMS: To explore the function of IRE1α/XBP1 in keloid fibroblasts and to investigate the potential mechanism of artesunate in inhibiting keloid hyperplasia. METHODS: Human keloid fibroblasts (KFs) were cultured, and the expressions of XBP1 and TGF-ß1 were detected by immunohistochemistry. The expression of IRE1 was interfered with through cell transfection and the effects of IRE1 interference on cell proliferation and the cell cycle were assessed using MTS, colony formation assays, and flow cytometry. Detection of the expressions of XBP1 and TGF-ß1 by qRT-PCR and Western blot. Then artesunate was applied to a subset of the cells, and its effects on cell viability and the expression of related proteins using the same methods. RESULTS: The IRE1α/XBP1 pathway was activated in KFs. Knocking out the gene IRE1α can inhibit the expression of TGF-ß1, in addition, the cell viability and cell cycle progression of KFs were also significantly affected. After artesunate treatment, there was a remarkable reduction in cell proliferation. Meanwhile, the cell cycle of KFs treated with artesunate was blocked in G1 phase.After upregulating the expression of IRE1α and treating KFs with artesunate, both cell cycle and proliferation showed inhibitory effects, and related proteins also exhibited suppressed expression. CONCLUSIONS: The IRE1α/XBP1 pathway is activated in keloid, and inhibiting the expression of this pathway can affect the cell proliferation activity. In addition, artesunate also has a significant effect on fibroblast proliferation, and the IRE1α/XBP1 pathway may participate in this process. These findings suggest that IRE1α/XBP1 signal pathway may be a potential target for scar treatment, and artesunate could also be a powerful candidate for keloid treatment.

Efficacy of artesunate-amodiaquine for treatment of uncomplicated Plasmodium falciparum malaria in mainland Tanzania.

BACKGROUND: Diversification of artemisinin-based combination therapy (ACT) is suggested as one of the strategies that can be used to contain artemisinin resistance. Artesunate-amodiaquine (ASAQ) is one of the artemisinin-based combinations that can be used in the diversification strategy as an alternative first-line treatment for uncomplicated malaria in mainland Tanzania. There is however limited data on the efficacy of ASAQ in mainland Tanzania. This study assessed the efficacy of ASAQ for treatment of uncomplicated Plasmodium falciparum malaria in selected sentinel sites for therapeutic efficacy studies in mainland Tanzania. METHODS: Between December 2018 and March 2020, children aged between 6 months and 10 years, attending at Nagaga, Mkuzi, and Mlimba primary health facilities, and with suspected uncomplicated malaria infection were screened for eligibility to participate in the study. Malaria infection was screened using microscopy. Children with uncomplicated P. falciparum monoinfection and who fulfilled all other inclusion criteria, and had none of the exclusion criteria, according to the World Health Organization (WHO) guidelines, were treated with ASAQ. Follow-up visits were scheduled on days 0, 1, 2, 3, 7, 14, 21, and 28 or on any day of recurrent infection for clinical and laboratory assessment. Polymerase chain reaction (PCR)-corrected cure rate on day 28 was the primary outcome. RESULTS: A total of 264 children, 88 in each of the three study sites (Mlimba, Mkuzi and Nagaga health facilities) were enrolled and treated with ASAQ. The ASAQ PCR-corrected cure rate was 100% at all the three study sites. None of the participants had early treatment failure or late clinical failure. Furthermore, none of the participants had a serious adverse event. CONCLUSION: ASAQ was highly efficacious for the treatment of uncomplicated P. falciparum malaria in mainland Tanzania, therefore, it can be deployed as an alternative first-line treatment for uncomplicated malaria as part of diversification strategy to contain the spread of partial artemisinin resistance in the country.