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Sharma S, Ramachandran A, Sharma A. Role of riboflavin deficiency in malaria pathophysiology. PLoS Pathog 2024; 20:e1011991. [PMID: 38427625 PMCID: PMC10906831 DOI: 10.1371/journal.ppat.1011991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024] Open
Abstract
The emergence of resistance against antimalarials and insecticides poses a significant threat to malaria elimination strategies. It is crucial to explore potential risk factors for malaria to identify new targets and alternative therapies. Malnutrition is a well-established risk factor for malaria. Deficiencies of micronutrients such as vitamin A, zinc, iron, folic acid, and phenotypic measures of malnutrition, such as stunting and wasting, have been studied extensively in the context of malaria. Vitamin B2, also known as riboflavin, is a micronutrient involved in maintaining cellular homeostasis. Riboflavin deficiency has been shown to have an inverse correlation with malarial parasitaemia. This article reviews the role of riboflavin in maintaining redox homeostasis and probes how riboflavin deficiency could alter malaria pathogenesis by disrupting the balance between oxidants and antioxidants. Though riboflavin analogues have been explored as antimalarials, new in vivo and patient-based research is required to target riboflavin-associated pathways for antimalarial therapy.
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Affiliation(s)
- Shweta Sharma
- ICMR–National Institute of Malaria Research, New Delhi, India
- ACSIR, Ghaziabad, Uttar Pradesh, India
| | - Arathy Ramachandran
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Amit Sharma
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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Roseoflavin, a Natural Riboflavin Analogue, Possesses In Vitro and In Vivo Antiplasmodial Activity. Antimicrob Agents Chemother 2022; 66:e0054022. [PMID: 36094195 PMCID: PMC9578400 DOI: 10.1128/aac.00540-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ability of the human malaria parasite Plasmodium falciparum to access and utilize vital nutrients is critical to its growth and proliferation. Molecules that interfere with these processes could potentially serve as antimalarials. We found that two riboflavin analogues, roseoflavin and 8-aminoriboflavin, inhibit malaria parasite proliferation by targeting riboflavin metabolism and/or the utilization of the riboflavin metabolites flavin mononucleotide and flavin adenine dinucleotide. An additional eight riboflavin analogues were evaluated, but none were found to be more potent than roseoflavin, nor was their activity on target. Focusing on roseoflavin, we tested its antimalarial activity in vivo against Plasmodium vinckei vinckei in mice. We found that roseoflavin decreased the parasitemia by 46-fold following a 4 day suppression test and, on average, increased the survival of mice by 4 to 5 days. Our data are consistent with riboflavin metabolism and/or the utilization of riboflavin-derived cofactors being viable drug targets for the development of new antimalarials and that roseoflavin could serve as a potential starting point.
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Thomson-Luque R, Adams JH, Kocken CHM, Pasini EM. From marginal to essential: the golden thread between nutrient sensing, medium composition and Plasmodium vivax maturation in in vitro culture. Malar J 2019; 18:344. [PMID: 31601222 PMCID: PMC6785855 DOI: 10.1186/s12936-019-2949-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/06/2019] [Indexed: 02/07/2023] Open
Abstract
Historically neglected, due to its biological peculiarities, the absence of a continuous long-term in vitro blood stage culture system and a propensity towards high morbidity rather than mortality, Plasmodium vivax was put back on the agenda during the last decade by the paradigm shift in the fight against malaria from malaria control to malaria eradication. While the incidence of the deadliest form of malaria, Plasmodium falciparum malaria, has declined since this paradigm shift took hold, the prospects of eradication are now threatened by the increase in the incidence of other human malaria parasite species. Plasmodium vivax is geographically the most widely distributed human malaria parasite, characterized by millions of clinical cases every year and responsible for a massive economic burden. The urgent need to tackle the unique biological challenges posed by this parasite led to renewed efforts aimed at establishing a continuous, long-term in vitro P. vivax blood stage culture. Based on recent discoveries on the role of nutrient sensing in Plasmodium’s pathophysiology, this review article critically assesses the extensive body of literature concerning Plasmodium culture conditions with a specific focus on culture media used in attempts to culture different Plasmodium spp. Hereby, the effect of specific media components on the parasite’s in vitro fitness and the maturation of the parasite’s host cell, the reticulocyte, is analysed. Challenging the wide-held belief that it is sufficient to find the right parasite isolate and give it the right type of cells to invade for P. vivax to grow in vitro, this review contends that a healthy side-by-side maturation of both the parasite and its host cell, the reticulocyte, is necessary in the adaptation of P. vivax to in vitro growth and argues that culture conditions and the media in particular play an essential role in this maturation process.
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Affiliation(s)
- Richard Thomson-Luque
- Center for Infectious Diseases-Parasitology, Heidelberg University Hospital, Im Neuenheimer Feld 324, 69120, Heidelberg, Germany.
| | - John H Adams
- Center for Global Health, & Infectious Diseases Research, Department of Global Health, College of Public Health, University of South Florida, 3720 Spectrum Blvd, Suite 404 IDRB, Tampa, FL, USA
| | - Clemens H M Kocken
- Department of Parasitology, Biomedical Primate Research Centre, Lange Kleiweg, 161, 2288 GJ, Rijswijk, The Netherlands
| | - Erica M Pasini
- Department of Parasitology, Biomedical Primate Research Centre, Lange Kleiweg, 161, 2288 GJ, Rijswijk, The Netherlands.
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Bilgin R, Yalcin MS, Yucebilgic G, Koltas IS, Yazar S. Oxidative stress in vivax malaria. THE KOREAN JOURNAL OF PARASITOLOGY 2012; 50:375-7. [PMID: 23230340 PMCID: PMC3514434 DOI: 10.3347/kjp.2012.50.4.375] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 07/11/2012] [Accepted: 07/25/2012] [Indexed: 02/05/2023]
Abstract
Malaria is still a leading cause of morbidity and mortality. The increase in lipid peroxidation reported in malaria infection and antioxidant status may be a useful marker of oxidative stress during malaria infection. The aim of this study was to investigate the role of antioxidant enzymes against toxic reactive oxygen species in patients infected with Plasmodium vivax and healthy controls. Malondialdehyde levels, superoxide dismutase, and glutathione peroxidase activities were determined in 91 P. vivax patients and compared with 52 controls. Malondialdehyde levels, superoxide dismutase, and glutathione peroxidase activities were 8.07±2.29 nM/ml, 2.69±0.33 U/ml, and 49.6±3.2 U/g Hb in the patient group and 2.72±0.50 nM/ml, 3.71±0.47 U/ml, and 62.3±4.3 U/g Hb in the control group, respectively. Malondialdehyde levels were found statistically significant in patients with vivax malaria higher than in healthy controls (P<0.001). On the other hand, superoxide dismutase and glutathione peroxidase activities were found to be significantly lower in vivax malaria patients than in controls (P<0.05). There was an increase in oxidative stress in vivax malaria. The results suggested that antioxidant defense mechanisms may play an important role in the pathogenesis of P. vivax.
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Affiliation(s)
- Ramazan Bilgin
- University of Cukurova, Arts & Science Faculty, Chemistry Department (Biochemistry Division), Adana, Turkey.
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Righetti AA, Koua AYG, Adiossan LG, Glinz D, Hurrell RF, N'goran EK, Niamké S, Wegmüller R, Utzinger J. Etiology of anemia among infants, school-aged children, and young non-pregnant women in different settings of South-Central Cote d'Ivoire. Am J Trop Med Hyg 2012; 87:425-34. [PMID: 22848097 DOI: 10.4269/ajtmh.2012.11-0788] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Anemia affects one-quarter of the world's population, but its etiology remains poorly understood. We determined the prevalence of anemia and studied underlying risk factors in infants (6-23 months), young school-aged children (6-8 years), and young non-pregnant women (15-25 years) in south-central Côte d'Ivoire. Blood, stool, and urine samples were subjected to standardized, quality-controlled methods. We found high prevalence of anemia, malaria, inflammation, and deficiencies of iron, riboflavin, and vitamin A but low prevalence and intensities of soil-transmitted helminth and schistosome infections. Multivariate regression analysis revealed significant associations between anemia and Plasmodium falciparum for infants, inflammation for school-aged children, and cellular iron deficiency for both school-aged children and non-pregnant women. Women with riboflavin deficiency had significantly lower odds of anemia. Our findings call for interventions to protect infants from malaria, improved intake of dietary iron, better access to health care, and health education.
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Affiliation(s)
- Aurélie A Righetti
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
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Sarma GN, Savvides SN, Becker K, Schirmer M, Schirmer RH, Karplus PA. Glutathione reductase of the malarial parasite Plasmodium falciparum: crystal structure and inhibitor development. J Mol Biol 2003; 328:893-907. [PMID: 12729762 DOI: 10.1016/s0022-2836(03)00347-4] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The malarial parasite Plasmodium falciparum is known to be sensitive to oxidative stress, and thus the antioxidant enzyme glutathione reductase (GR; NADPH+GSSG+H(+) <==> NADP(+)+2 GSH) has become an attractive drug target for antimalarial drug development. Here, we report the 2.6A resolution crystal structure of P.falciparum GR. The homodimeric flavoenzyme is compared to the related human GR with focus on structural aspects relevant for drug design. The most pronounced differences between the two enzymes concern the shape and electrostatics of a large (450A(3)) cavity at the dimer interface. This cavity binds numerous non-competitive inhibitors and is a target for selective drug design. A 34-residue insertion specific for the GRs of malarial parasites shows no density, implying that it is disordered. The precise location of this insertion along the sequence allows us to explain the deleterious effects of a mutant in this region and suggests new functional studies. To complement the structural comparisons, we report the relative susceptibility of human and plasmodial GRs to a series of tricyclic inhibitors as well as to peptides designed to interfere with protein folding and dimerization. Enzyme-kinetic studies on GRs from chloroquine-resistant and chloroquine-sensitive parasite strains were performed and indicate that the structure reported here represents GR of P.falciparum strains in general and thus is a highly relevant target for drug development.
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Affiliation(s)
- G N Sarma
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331-7305, USA
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7
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Abstract
Malaria is a leading cause of morbidity and mortality worldwide, and anemia is a common and sometimes serious complication of Plasmodium falciparum infection. Although micronutrient malnutrition is usually highly prevalent in malaria endemic areas, the contribution of micronutrient deficiencies to malarial anemia is often overlooked. Recent investigation suggests that micronutrients such as vitamin A, vitamin E, and zinc, may improve the morbidity of malaria through immune modulation and alteration of oxidative stress. Micronutrients are also involved in the pathogenesis of anemia and likely play a role in malarial anemia, but many clinical trials have not specifically addressed the impact of micronutrient supplementation on malarial anemia. Further work is needed to assess the effect of both clinic and community-based micronutrient interventions on malarial anemia in infants, children, and pregnant women.
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Affiliation(s)
- Veronique Nussenblatt
- Department of Ophthalmology, Center for Human Nutrition, Johns Hopkins University School of Medicine, 550 No. Bdwy., Suite 700, Baltimore, MD 21205, USA
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Abstract
This review critically examines the relationship between nutritional status and malaria. The data indicate that protein-energy malnutrition is associated with greater malaria morbidity and mortality in humans. In addition, controlled trials of either vitamin A or zinc supplementation show that these nutrients can substantially reduce clinical malaria attacks. Data for iron indicate that supplementation may minimally aggravate certain malariometric indices in some settings and also strongly improve hematologic status. Withholding of iron supplements from deficient population is, therefore, not currently indicated. Available evidence for other nutrients describe varied effects, with some deficiencies being exacerbative (e.g., thiamine), protective (e.g., vitamin E), or both exacerbative and protective in different settings (e.g., riboflavin, vitamin C). The roles of folate, other B vitamins, unsaturated fatty acids, amino acids, and selenium are also examined. Study of the interactions between nutrition and malaria may provide insight to protective mechanisms and result in nutrient-based interventions as low-cost and effective adjuncts to current methods of malaria prevention and treatment.
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Affiliation(s)
- A H Shankar
- Departments of International Health and of Molecular Microbiology and Immunology, Johns Hopkins School of Hygiene and Public Health, Baltimore, Maryland, USA.
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Akompong T, Ghori N, Haldar K. In vitro activity of riboflavin against the human malaria parasite Plasmodium falciparum. Antimicrob Agents Chemother 2000; 44:88-96. [PMID: 10602728 PMCID: PMC89633 DOI: 10.1128/aac.44.1.88-96.2000] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human malaria parasite Plasmodium falciparum digests hemoglobin and polymerizes the released free heme into hemozoin. This activity occurs in an acidic organelle called the food vacuole and is essential for survival of the parasite in erythrocytes. Since acidic conditions are known to enhance the auto-oxidation of hemoglobin, we investigated whether hemoglobin ingested by the parasite was oxidized and whether the oxidation process could be a target for chemotherapy against malaria. We released parasites from their host cells and separately analyzed hemoglobin ingested by the parasites from that remaining in the erythrocytes. Isolated parasites contained elevated amounts (38.5% +/- 3.5%) of oxidized hemoglobin (methemoglobin) compared to levels (0.8% +/- 0.2%) found in normal, uninfected erythrocytes. Further, treatment of infected cells with the reducing agent riboflavin for 24 h decreased the parasite methemoglobin level by 55%. It also inhibited hemozoin production by 50% and decreased the average size of the food vacuole by 47%. Administration of riboflavin for 48 h resulted in a 65% decrease in food vacuole size and inhibited asexual parasite growth in cultures. High doses of riboflavin are used clinically to treat congenital methemoglobinemia without any adverse side effects. This activity, in conjunction with its impressive antimalarial activity, makes riboflavin attractive as a safe and inexpensive drug for treating malaria caused by P. falciparum.
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Affiliation(s)
- T Akompong
- Departments of Pathology and Microbiology-Immunology, Northwestern University Medical School, Chicago, Illinois 60611-3008, USA.
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Adelekan DA, Thurnham DI. Glutathione peroxidase (EC 1.11.1.9) and superoxide dismutase (EC 1.15.1.1) activities in riboflavin-deficient rats infected with Plasmodium berghei malaria. Br J Nutr 1998; 79:305-9. [PMID: 9577309 DOI: 10.1079/bjn19980048] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Riboflavin deficiency interferes with the growth and multiplication of malaria parasites as well as the host response to malaria. The objective of the present work was to determine the effects of riboflavin deficiency on erythrocyte glutathione peroxidase (EC 1.11.1.9; GPx) and superoxide dismutase (EC 1.15.1.1; SOD) in rats infected with Plasmodium berghei malaria. Riboflavin in its co-enzyme form, FAD, is required by glutathione reductase (EC 1.6.4.1) to regenerate GSH and GSH is an important cellular antioxidant both in its own right and also as a substrate for the enzyme GPx. Weanling rats were deprived of riboflavin for 8 weeks before intraperitoneal injection of 1 x 10(6) P. berghei parasites. Control animals were weight-matched to the respective riboflavin-deficient group. At 10 d post-infection, parasite counts were higher in the weight-matched control group than the riboflavin-deficient group (P = 0.004). GPx activity was higher in erythrocytes of rats parasitized with P. berghei than comparable non-infected rats regardless of riboflavin status (P < 0.05). As mature erythrocytes do not synthesize new protein, the higher GPx activities were probably due to the presence of the parasite protein. In erythrocytes from riboflavin-deficient rats, GPx activity tended to be lower than in those rats fed on diets adequate in riboflavin (weight-matched controls) whether parasitized or not, but the difference was not significant. Neither riboflavin deficiency nor malaria had any effect on erythrocyte SOD activity. It was concluded that riboflavin deficiency has no marked effect on erythrocyte GPx or SOD activity in the rat.
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Affiliation(s)
- D A Adelekan
- Department of Community Health, Faculty of Clinical Sciences, College of Health Sciences, Obafemi Awolowo University, Ile-lfe, Nigeria.
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11
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Erel O, Kocyigit A, Avci S, Aktepe N, Bulut V. Oxidative stress and antioxidative status of plasma and erythrocytes in patients with vivax malaria. Clin Biochem 1997; 30:631-9. [PMID: 9455617 DOI: 10.1016/s0009-9120(97)00119-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES To investigate the oxidative stress and antioxidative status of plasma and erythrocytes in patients with vivax malaria and healthy persons. DESIGN AND METHODS Activities of antioxidative enzymes, rates of pathways of hexose monophosphate shunt and purine salvage, levels of lipid peroxidation, reduced glutathione, methemoglobin and sulfhemoglobin of erythrocytes were determined. Lipid peroxidation and levels of antioxidant substances were measured. RESULTS Antioxidants levels and antioxidative enzymes activities were lower and lipid peroxidation, purine salvage rate were higher in patients group than controls. Erythrocyte glucose-6 phosphate dehydrogenase (G-6-PD) activity was not different from that of healthy subjects. CONCLUSIONS Oxidative mechanisms were observed to be dominant compared with antioxidative mechanisms in patients with vivax malaria. Therefore, oxidative stress may be produced and maintained by the host defense mechanisms against malarial infection.
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Affiliation(s)
- O Erel
- Department of Clinical Biochemistry, Faculty of Medicine, Harran University, Sanliurfa-Turkey.
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12
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Färber PM, Becker K, Müller S, Schirmer RH, Franklin RM. Molecular cloning and characterization of a putative glutathione reductase gene, the PfGR2 gene, from Plasmodium falciparum. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 239:655-61. [PMID: 8774709 DOI: 10.1111/j.1432-1033.1996.0655u.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recently, glutathione reductase (GR) has emerged as a promising target for antiparasitic drugs. The central role of GR in cellular antioxidant defence, the particular susceptibility of intracellular parasites like Plasmodium falciparum to oxidative stress, and successful inhibitor studies substantiate this approach. However, more information is required on the structural and functional characteristics of GR from malarial parasites and differences from the enzyme of host erythrocytes. We have identified a putative P. falciparum GR gene coding for a polypeptide (PfGR2) of 500 amino acids that exhibits 40-45% sequence identity with GR enzymes from other species. 18 out of 19 residues contributing to glutathione binding are identical in the putative PfGR2 and human GR. According to Southern blot analysis, the PfGR2 gene is present as a single-copy gene. It is expressed during the intraerythrocytic life cycle. Stage-specific Northern blot analysis demonstrates that the PfGR2 gene is only weakly transcribed in ring, early trophozoite, and segmenter stages; major transcription occurs in the late trophozoite/early schizont stage. This is consistent with the high glutathione reductase activity found in early schizonts. Other data also suggest that PfGR2 corresponds to the enzyme isolated from parasitized erythrocytes. These criteria include the subunit molecular mass (56.2 kDa), the N-terminal sequence (VYDLIVIGGGSGGMA), the presence of specific sequence motifs at ligand-binding sites, and, as demonstrated by Western blotting, the occurrence of a unique chain segment in the core of the central domain. In view of these data, the function(s) of PfGR2 as well as PfGR1, the product of another GR-like gene of P. falciparum (Müller et al., 1995) should be carefully assessed.
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Affiliation(s)
- P M Färber
- Biozentrum der Universität Basel, Switzerland
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13
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Abstract
Previous studies indicate a suppressive influence of fish oils on rodent malaria. The present work was carried out to study (i) the dose-effect relation between dietary fish oils and lethality of primary malaria infection in mice; (ii) the modifying influence of vitamin E; and (iii) the effect of previous fish oil feeding on parasitemia and lethality of a rechallenge infection. For two or four weeks, groups of weanling male mice were fed a standard laboratory diet or one of eight purified diets containing various amounts of fish oil (providing 6-21% of energy). The diets were prepared with and without vitamin E. After the two- or four-week feeding period, the mice were injected intraperitoneally with Plasmodium yoelii-infected erythrocytes. Six months after the primary infection (four months after discontinuing fish oil feeding), the surviving mice were again injected intraperitoneally with parasitized red blood cells (or even better--erythrocytes, erythrocytes are used elsewhere). Primary malaria infection was lethal in mice fed standard diet alone or with fish oil and vitamin E added. In contrast, feeding a fish oil-based diet without vitamin E improved survival to at least 70% if the mice had been fed these diets for four weeks. Protection against malaria did not seem to be related to the fish oil dose used. Regardless of the previous fish oil dose, all the mice surviving the primary infection survived the rechallenge infection with low parasitaemias.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P Fevang
- Center for Tropical Parasitic Diseases, Department of Microbiology and Immunology, Miami, Florida, USA
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Affiliation(s)
- B Anderson
- Division of Paediatrics, Arcispedale S Anna, Ferrara, Italy
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15
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Abstract
In situations where malaria eradication is not an option in the foreseeable future the emphasis must be on the control of morbidity and mortality due to malaria. Under such circumstances drawing a distinction between malarial parasitization and malarial disease may be important for workers in both field and laboratory. This concept is explored from the points of view of the epidemiological picture of malaria in endemic populations, the factors which may influence progression to disease and the processes which mediate disease.
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Affiliation(s)
- K Marsh
- Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford
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Affiliation(s)
- N J White
- Wellcome-Mahidol University, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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17
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Snow RW, Byass P, Shenton FC, Greenwood BM. The relationship between anthropometric measurements and measurements of iron status and susceptibility to malaria in Gambian children. Trans R Soc Trop Med Hyg 1991; 85:584-9. [PMID: 1780980 DOI: 10.1016/0035-9203(91)90351-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Anthropometric measurements were made and serum iron and ferritin levels determined in a group of Gambian children at the beginning of the rainy season and these findings were related to the malaria experience of the children during the following malaria transmission season. Susceptibility to malaria was not correlated with prior weight-for-age, height-for-age, weight-for-height or serum albumin, or with serum iron, serum iron binding capacity nor serum ferritin. Thus, our findings do not provide any support for the view that poor nutritional status, as assessed by anthropometric measurements, or iron deficiency protect against malaria infection. Children who developed a clinical attack of malaria accompanied by a high level of parasitaemia tended to have a higher mean weight-for-age at the beginning of the rainy season than did children who had a clinical attack accompanied by a low level of parasitaemia, but the difference between groups was not statistically significant. However, they had a significantly higher mean serum ferritin level (P less than 0.01).
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Affiliation(s)
- R W Snow
- Medical Research Council Laboratories, Fajara, Banjul, The Gambia
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18
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Dutta P. Enhanced uptake and metabolism of riboflavin in erythrocytes infected with Plasmodium falciparum. THE JOURNAL OF PROTOZOOLOGY 1991; 38:479-83. [PMID: 1920146 DOI: 10.1111/j.1550-7408.1991.tb04820.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Riboflavin deficiency inhibits the growth of malaria parasites both in vitro and in vivo in infected animals and humans. Although the precise mechanisms underlying this inhibition are unknown, they may involve enhanced requirements for riboflavin by parasites. To investigate this possibility, the rate of uptake of [14C]riboflavin and the biosynthesis of FMN and FAD from riboflavin were studied in infected (5-8% parasitemia) and uninfected human erythrocytes. All cells were incubated for 0-3 h at 37 degrees C in phosphate buffered saline containing MgCl2, glucose, and [14C]riboflavin (2.5-7.5 microM). At hourly intervals, samples were removed, centrifuged, washed twice with cold buffer, and lysed before counting the radioactivity. The rate of in vitro biosynthesis of FMN and FAD from riboflavin in erythrocytes was measured by ion exchange chromatography and reverse isotope dilution techniques. Results showed that the rate of riboflavin uptake and the biosynthesis of FMN and FAD were enhanced in erythrocytes with parasitemia as compared with results in unparasitized erythrocytes. Riboflavin uptake in erythrocytes was proportional to the extent of parasitemia and especially to percent of schizonts present in erythrocytes. These studies indicate that the requirement for riboflavin may be greater in the parasite than in the host erythrocyte. This increased riboflavin requirement may be due to rapid multiplication, higher metabolic rate, and extreme vulnerability to oxidative stress of malaria parasites compared with that of host erythrocytes. The differential requirement of riboflavin by the host and the malaria parasite may hold important potential for developing new strategies for malaria chemotherapy.
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Affiliation(s)
- P Dutta
- Memorial Sloan-Kettering Cancer Center, Cornell University Medical Center, New York, New York 10021
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19
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Halladay PK, Hunt NH, Butcher GA, Cowden WB. Antimalarial action of flavin analogues seems not be due to inhibition of glutathione reductase of host erythrocytes. Biochem Pharmacol 1990; 39:1063-5. [PMID: 2182031 DOI: 10.1016/0006-2952(90)90285-s] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A series of 10-(4'-chlorophenyl)-3-substituted flavins (1a-f) were examined with respect to their antimalarial properties. They were tested against Plasmodium falciparum in vitro and Plasmodium vinckei vinckei in vivo. The proposition that they might act through glutathione reductase (GR) (EC 1.6.4.2) inhibition has been studied. Inhibition of P. falciparum in vitro by these compounds shows only slight variation between analogues; in contrast, inhibition of human erythrocyte GR by members of the same series is highly variable, indicating that this is probably not their primary mode of antimalarial action. Results of the P. vinckei vinckei screen showed that 10-(4'-chlorophenyl)-3-methyl,3-ethyl and 3-propyl substituted flavins are active in vivo over the dose range screened (10-70 mg/kg).
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Affiliation(s)
- P K Halladay
- Division of Cell Biology, John Curtin School of Medical Research, Canberra, A.C.T, Australia
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Becker K, Christopherson RI, Cowden WB, Hunt NH, Schirmer RH. Flavin analogs with antimalarial activity as glutathione reductase inhibitors. Biochem Pharmacol 1990; 39:59-65. [PMID: 2404494 DOI: 10.1016/0006-2952(90)90648-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
10-(4'-Chlorophenyl)-3-methylflavin has antimalarial activity in vitro and in vivo (Cowden et al., J Med Chem 31: 799, 1988). This flavin analog and two of its derivatives were found to inhibit the antioxidant flavoenzyme glutathione reductase from human erythrocytes in its isolated form as well as in hemolysates. The mixed-type inhibition was completely reversible, the Ki-values being of the order of 1 microM. Surprisingly, the drugs were not competitive with FAD, but with GSSG, one of the enzyme's substrates. Malaria parasite glutathione reductase, extracted from Plasmodium falciparum, could also be inhibited by the compounds. Studies on the effects of the substances on P. falciparum in vitro, which were demonstrated morphologically and by growth inhibition, confirmed previous observations with 10-(4'-chlorophenyl)-3-methylflavin and showed similar parasiticidal characteristics for the two new derivatives. The activities of five other erythrocytic enzymes tested were not impaired by the drugs, nor was the nucleotide metabolism of erythrocytes and/or parasites significantly changed. Permeation into red blood cells was demonstrated for one compound by 19F-NMR-spectroscopy. Inhibition of glutathione reductase might contribute to, or account for, the antimalarial activity of this group of flavin analogs.
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Affiliation(s)
- K Becker
- Department of Pathology, Medical School, University of Sydney, N.S.W., Australia
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Dutta P, Pinto J, Rivlin R. Antimalarial properties of imipramine and amitriptyline. THE JOURNAL OF PROTOZOOLOGY 1990; 37:54-8. [PMID: 2406432 DOI: 10.1111/j.1550-7408.1990.tb01116.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Dietary riboflavin deficiency is known to diminish malarial parasitemia. In this study, we determined whether imipramine and amitriptyline, drugs which inhibit riboflavin metabolism, have antimalarial efficacy. In addition, we evaluated whether these drugs, like other antimalarial agents, increase the hemolytic response to ferriprotoporphyrin IX (FP). The growth of Plasmodium falciparum (FCR3) in the absence and presence of these drugs (10 to 75 microM) was measured by determining (3H)hypoxanthine uptake by intra-erythrocytic parasites for 48 h in RPMI 1640 medium. The uptake of (3H)hypoxanthine was significantly reduced in a dose-dependent manner by both imipramine and amitriptyline. The IC50 values of imipramine and amitriptyline at 48 h were 56 and 45 microM, respectively. Both drugs enhanced hemolysis induced by FP (10 or 20 microM). No hemolysis by these drugs was detected in the absence of FP. It is concluded that the tricyclic antidepressants, imipramine and amitriptyline, possess substantial antimalarial properties.
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Affiliation(s)
- P Dutta
- Memorial Sloan-Kettering Cancer Center, New York, New York
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Viera BB. Effect of antimalarial drugs and of clindamycin on erythrocyte metabolism: a review. Rev Inst Med Trop Sao Paulo 1989. [DOI: 10.1590/s0036-46651989000300011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Barraviera B, Machado PE, Meira DA. Glutathione reductase activity and its relation with riboflavin levels measured by methemoglobin reduction by cystamine in patients with malaria (preliminary report). Rev Inst Med Trop Sao Paulo 1988; 30:107-8. [PMID: 3059438 DOI: 10.1590/s0036-46651988000200010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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Affiliation(s)
- W B Cowden
- John Curtin School of Medical Research, Australian National University, Canberra
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Bates CJ, Powers HJ, Lamb WH, Gelman W, Webb E. Effect of supplementary vitamins and iron on malaria indices in rural Gambian children. Trans R Soc Trop Med Hyg 1987; 81:286-91. [PMID: 3617193 DOI: 10.1016/0035-9203(87)90244-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The effect of a combined supplement of iron, thiamine, riboflavin and vitamin C on malarial incidence in 5 to 14-year-old children was tested in a malnourished rural community in a region of The Gambia noted for high prevalence of malaria during the rainy season. 190 children, divided into 2 matched groups, received either the supplement or a matching placebo for 3 months. No significant difference in malarial incidence was observed between the 2 groups, despite a major improvement in biochemical indices of nutrient status in the supplemented group, especially for riboflavin and vitamin C. Severity of episodes was also similar between groups, but in subjects who developed parasitaemias there was a trend towards higher parasite counts in those receiving the active supplement. Nutritional interventions in malarious areas may have adverse effects on malaria, and the increase in parasitaemia was compatible with the hypothesis that a small but significant reduction in defences had occurred. However, the absence of increases in the incidence of proven malaria cases and their severity must also be taken into account, in order to make a balanced assessment of the possible increase in risk. Further investigations are needed to measure the risk in benefit rates, and to consider the effects of individual nutrients in isolation.
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Divo AA, Geary TG, Davis NL, Jensen JB. Nutritional requirements of Plasmodium falciparum in culture. I. Exogenously supplied dialyzable components necessary for continuous growth. THE JOURNAL OF PROTOZOOLOGY 1985; 32:59-64. [PMID: 3886898 DOI: 10.1111/j.1550-7408.1985.tb03013.x] [Citation(s) in RCA: 168] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Continuous cultivation of Plasmodium falciparum presently requires the nutritionally complex medium, RPMI 1640. A basal medium of KCl, NaCl, Na2HPO4, Ca(NO3)2, MgSO4, glucose, reduced glutathione, HEPES buffer, hypoxanthine, phenol red (in RPMI 1640 concentrations), and 10% (v/v) exhaustively dialyzed pooled human serum was used to determine which vitamins and amino acids had to be exogenously supplied for continuous cultivation. Supplementation of basal medium with calcium pantothenate, cystine, glutamate, glutamine, isoleucine, methionine, proline, and tyrosine was necessary for continuous growth. This semi-defined minimal medium supported continuous growth of four isolates of P. falciparum at rates slightly less than those obtained with RPMI 1640. Adding any other vitamin or amino acid did not improve growth. Incorporation of several non-essential amino acids, particularly phenylalanine and leucine, into proteins was markedly enhanced in the minimal medium compared to RPMI 1640.
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