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Hepatology Communications Jun 2017We report a novel association between the commonly used antimalarial medication atovaquone/proguanil and drug-induced autoimmune-like hepatitis. The patient developed...
We report a novel association between the commonly used antimalarial medication atovaquone/proguanil and drug-induced autoimmune-like hepatitis. The patient developed severe liver disease fulfilling biochemical, immunologic, and histologic criteria for the diagnosis of autoimmune hepatitis after the inadvertent rechallenge with the offending drug, which had caused self-limited hepatitic symptoms a year previously. Over a period of 18 months, the patient underwent two follow-up liver biopsies showing progressive resolution of the liver inflammation and achieved complete biochemical and immunologic remission on steroids. This remission persisted for 20 months following treatment withdrawal. : This well documented case raises awareness of the potential hepatotoxicity of atovaquone/proguanil. ( 2017;1:293-298).
PubMed: 29404460
DOI: 10.1002/hep4.1039 -
Cureus Feb 2019Tick-borne diseases are frequently seen in tick-inhabited areas. Lyme disease is the most common tick-borne illness. However, patients with co-infections can present...
Tick-borne diseases are frequently seen in tick-inhabited areas. Lyme disease is the most common tick-borne illness. However, patients with co-infections can present with nonspecific symptoms, which can make the diagnosis far more challenging. We present a case of triple infection with babesiosis, Lyme disease, and anaplasmosis treated with antibiotics and red blood cell (RBC) exchange (erythrocytapheresis). A 74-year-old, avid female gardener presented with one week of progressive dyspnea, cough with mucoid expectoration, and fatigue. On presentation, she was afebrile, hypotensive, and tachycardic. General examination was significant for altered mental status, dyspnea, pallor, and peripheral edema. Lung examination was remarkable for bibasilar crackles. Pertinent laboratory findings were significant for hemolytic anemia and thrombocytopenia. A peripheral blood smear revealed the presence of intracytoplasmic parasites consistent with Babesia. The patient was started on azithromycin and atovaquone. Doxycycline was added empirically for Lyme disease, which was later confirmed by serology. In addition, Anaplasma titers were also positive. Further investigation revealed that the parasitic load was 9.04%, and RBC exchange (erythrocytapheresis) was performed for severe babesiosis. Repeat laboratory tests demonstrated an inadequate reduction in parasitic load (6.54%), requiring a second round of RBC exchange. Antimicrobials were changed to clindamycin, quinine, and doxycycline for a total of 14 days. There was an improvement in the patient's anemia and thrombocytopenia along with clinical improvement.
PubMed: 31016091
DOI: 10.7759/cureus.4064 -
The British Journal of Radiology Jan 2019The concept of tumour hypoxia as a cause of radiation resistance has been prevalent for over 100 years. During this time, our understanding of tumour hypoxia has matured... (Review)
Review
The concept of tumour hypoxia as a cause of radiation resistance has been prevalent for over 100 years. During this time, our understanding of tumour hypoxia has matured with the recognition that oxygen tension within a tumour is influenced by both diffusion and perfusion mechanisms. In parallel, clinical strategies to modify tumour hypoxia with the expectation that this will improve response to radiation have been developed and tested in clinical trials. Despite many disappointments, meta-analysis of the data on hypoxia modification confirms a significant impact on both tumour control and survival. Early trials evaluated hyperbaric oxygen followed by a generation of studies testing oxygen mimetics such as misonidazole, pimonidazole and etanidazole. One highly significant result stands out from the use of nimorazole in advanced laryngeal cancer with a significant advantage seen for locoregional control using this radiosensitiser. More recent studies have evaluated carbogen and nicotinamide targeting both diffusion related and perfusion related hypoxia. A significant survival advantage is seen in muscle invasive bladder cancer and also for locoregional control in hypopharygeal cancer associated with a low haemoglobin. New developments include the recognition that mitochondrial complex inhibitors reducing tumour oxygen consumption are potential radiosensitising agents and atovaquone is currently in clinical trials. One shortcoming of past hypoxia modifying trials is the failure to identify oxygenation status and select those patient with significant hypoxia. A range of biomarkers are now available including histological necrosis, immunohistochemical intrinsic markers such as CAIX and Glut 1 and hypoxia gene signatures which have been shown to predict outcome and will inform the next generation of hypoxia modifying clinical trials.
Topics: Animals; Cell Hypoxia; Female; Humans; Male; Misonidazole; Neoplasms; Niacinamide; Oxygen Consumption; Radiation-Sensitizing Agents; Randomized Controlled Trials as Topic; Risk Assessment; Survival Analysis; Treatment Outcome; Tumor Hypoxia
PubMed: 29979089
DOI: 10.1259/bjr.20170966 -
Pathogens (Basel, Switzerland) Sep 2021Babesiosis is an emerging tick-borne disease caused by apicomplexan parasites of the genus . With its increasing incidence worldwide and the risk of human-to-human... (Review)
Review
Babesiosis is an emerging tick-borne disease caused by apicomplexan parasites of the genus . With its increasing incidence worldwide and the risk of human-to-human transmission through blood transfusion, babesiosis is becoming a rising public health concern. The current arsenal for the treatment of human babesiosis is limited and consists of combinations of atovaquone and azithromycin or clindamycin and quinine. These combination therapies were not designed based on biological criteria unique to parasites, but were rather repurposed based on their well-established efficacy against other apicomplexan parasites. However, these compounds are associated with mild or severe adverse events and a rapid emergence of drug resistance, thus highlighting the need for new therapeutic strategies that are specifically tailored to parasites. Herein, we review ongoing babesiosis therapeutic and management strategies and their limitations, and further review current efforts to develop new, effective, and safer therapies for the treatment of this disease.
PubMed: 34578153
DOI: 10.3390/pathogens10091120 -
Biology of Blood and Marrow... Sep 2018
Topics: Atovaquone; Hematopoietic Stem Cell Transplantation; Incidence
PubMed: 29909155
DOI: 10.1016/j.bbmt.2018.06.012 -
Molecules (Basel, Switzerland) May 2021Enzymes are highly specific biological catalysts that accelerate the rate of chemical reactions within the cell. Our knowledge of how enzymes work remains incomplete.... (Review)
Review
Enzymes are highly specific biological catalysts that accelerate the rate of chemical reactions within the cell. Our knowledge of how enzymes work remains incomplete. Computational methodologies such as molecular mechanics (MM) and quantum mechanical (QM) methods play an important role in elucidating the detailed mechanisms of enzymatic reactions where experimental research measurements are not possible. Theories invoked by a variety of scientists indicate that enzymes work as structural scaffolds that serve to bring together and orient the reactants so that the reaction can proceed with minimum energy. Enzyme models can be utilized for mimicking enzyme catalysis and the development of novel prodrugs. Prodrugs are used to enhance the pharmacokinetics of drugs; classical prodrug approaches focus on alternating the physicochemical properties, while chemical modern approaches are based on the knowledge gained from the chemistry of enzyme models and correlations between experimental and calculated rate values of intramolecular processes (enzyme models). A large number of prodrugs have been designed and developed to improve the effectiveness and pharmacokinetics of commonly used drugs, such as anti-Parkinson (dopamine), antiviral (acyclovir), antimalarial (atovaquone), anticancer (azanucleosides), antifibrinolytic (tranexamic acid), antihyperlipidemia (statins), vasoconstrictors (phenylephrine), antihypertension (atenolol), antibacterial agents (amoxicillin, cephalexin, and cefuroxime axetil), paracetamol, and guaifenesin. This article describes the works done on enzyme models and the computational methods used to understand enzyme catalysis and to help in the development of efficient prodrugs.
Topics: Acyclovir; Atenolol; Atovaquone; Catalysis; Chemistry, Pharmaceutical; Decitabine; Dopamine; Enzymes; Hydrogen-Ion Concentration; Hydrolysis; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Molecular Conformation; Nucleosides; Phenylephrine; Prodrugs; Protons; Quantum Theory; Software; Technology, Pharmaceutical; Temperature; Tranexamic Acid
PubMed: 34071328
DOI: 10.3390/molecules26113248 -
Reproduction (Cambridge, England) Jun 2023Developing novel therapies to cure and manage endometriosis is a major unmet need that will benefit over 180 million women worldwide. Results from the current study...
IN BRIEF
Developing novel therapies to cure and manage endometriosis is a major unmet need that will benefit over 180 million women worldwide. Results from the current study suggest that inhibitors of oxidative phosphorylation may serve as novel agents for the treatment of endometriosis.
ABSTRACT
Current therapeutic strategies for endometriosis focus on symptom management and are not curative. Here, we provide evidence supporting the inhibition of oxidative phosphorylation (OXPHOS) as a novel treatment strategy for endometriosis. Additionally, we report an organotypic organ-on-a-chip luminal model for endometriosis. The OXPHOS inhibitors, curcumin, plumbagin, and the FDA-approved anti-malarial agent, atovaquone, were tested against the endometriosis cell line, 12Z, in conventional as well as the new organotypic model. The results suggest that all three compounds inhibit proliferation and cause cell death of the endometriotic cells by inhibiting OXPHOS and causing an increase in intracellular oxygen radicals. The oxidative stress mediated by curcumin, plumbagin, and atovaquone causes DNA double-strand breaks as indicated by the elevation of phospho-γH2Ax. Mitochondrial energetics shows a significant decrease in oxygen consumption in 12Z cells. These experiments also highlight differences in the mechanism of action as curcumin and plumbagin inhibit complex I whereas atovaquone blocks complexes I, II, and III. Real-time assessment of cells in the lumen model showed inhibition of migration in response to the test compounds. Additionally, using two-photon lifetime imaging, we demonstrate that the 12Z cells in the lumen show decreased redox ratio (NAD(P)H/FAD) and lower fluorescence lifetime of NAD(P)H in the treated cells confirming major metabolic changes in response to inhibition of mitochondrial electron transport. The robust chemotoxic responses observed with atovaquone suggest that this anti-malarial agent may be repurposed for the effective treatment of endometriosis.
Topics: Female; Humans; Curcumin; Atovaquone; Antimalarials; Oxidative Phosphorylation; Endometriosis; NAD; Antineoplastic Agents; Cell Proliferation
PubMed: 37068140
DOI: 10.1530/REP-22-0265 -
BMC Cancer Nov 2023Colorectal cancer is a common malignant tumour. Invasive growth and distant metastasis are the main characteristics of its malignant biological behaviour, and they are...
BACKGROUND
Colorectal cancer is a common malignant tumour. Invasive growth and distant metastasis are the main characteristics of its malignant biological behaviour, and they are also the primary factors leading to death in colon cancer patients. Atovaquone is an antimalarial drug, and its anticancer effect has recently been demonstrated in several cancer models in vitro and in vivo, but it has not been examined in the treatment of colorectal cancer.
METHODS
To elucidate the effect of atovaquone on colorectal cancer. We used RNA transcriptome sequencing, RT‒PCR and Western blot experiments to examine the expression of NF-κB (p-P65), EMT-related proteins and related inflammatory factors (IL1B, IL6, CCL20, CCL2, CXCL8, CXCL6, IL6ST, FAS, IL10 and IL1A). The effect of atovaquone on colorectal cancer metastasis was validated using an animal model of lung metastases. We further used transcriptome sequencing, the GCBI bioinformatics database and the STRING database to predict relevant target proteins. Furthermore, pathological sections were collected from relevant cases for immunohistochemical verification.
RESULTS
This study showed that atovaquone could inhibit colorectal cancer metastasis and invasion in vivo and in vitro, inhibit the expression of E-cadherin protein, and promote the protein expression of N-cadherin, vimentin, ZEB1, Snail and Slug. Atovaquone could inhibit EMT by inhibiting NF-κB (p-P65) and related inflammatory factors. Further bioinformatics analysis and verification showed that PDGFRβ was one of the targets of atovaquone.
CONCLUSION
In summary, atovaquone can inhibit the expression of NF-κB (p-P65) and related inflammatory factors by inhibiting the protein expression of p-PDGFRβ, thereby inhibiting colorectal cancer metastasis. Atovaquone may be a promising drug for the treatment of colorectal cancer metastasis.
Topics: Animals; Humans; NF-kappa B; Atovaquone; Cell Line, Tumor; Signal Transduction; Colorectal Neoplasms; Epithelial-Mesenchymal Transition; Cell Movement
PubMed: 37932661
DOI: 10.1186/s12885-023-11585-9