Hemoglobin C associated with protection from severe malaria in the Dogon of Mali, a West African population with a low prevalence of hemoglobin S

The malaria hypothesis proposes a survival advantage for individuals with hemoglobin variants in areas of endemic Plasmodium falciparum malaria. Hemoglobin C (HbC) is a possible example in West Africa, where this hemoglobin has a centric distribution with high frequencies among certain populations including the Dogon ethnic group. To test whether HbC is associated with protection from malaria, we performed a case-control study in the Dogon of Bandiagara, Mali. HbC was present in 68 of 391 (17.4%) of uncomplicated malaria control cases, whereas it was detected in only 3 of 67 cases (4.5%) of severe malaria (odds ratio [OR], 0.22; P =. 01). Further, HbC was present in only 1 of 34 cases (2.9%) with cerebral manifestations, the most common presentation of severe malaria in this population (OR, 0.14; P =.03). Episodes of uncomplicated malaria and parasitemias (4800-205 050/microL) were identified in cases of homozygous HbC (HbCC), which indicates that P falciparum parasites are able to efficiently replicate within HbCC erythrocytes in vivo. These findings suggest that HbC does not protect against infection or uncomplicated malaria but can protect against severe malaria in the Dogon population of Bandiagara, Mali. The data also suggest that the protective effect associated with HbC may be greater than that of HbS in this population.     

Association of Schistosoma haematobium infection with protection against acute Plasmodium falciparum malaria in Malian children

Plasmodium falciparum and Schistosoma haematobium are co-endemic parasitic diseases with worldwide distribution. Evidence suggests interactions occur between helminthic and malaria infections, although it is unclear whether this effect is beneficial or harmful to the host. Malian children 4-14 years of age with asymptomatic S. haematobium infection (SP) (n = 338) were prospectively matched by age, sex, and residence to children without schistosomiasis (SN) (n = 338) who were cleared of occult intestinal parasites, and followed-up for one malaria transmission season (25 weeks). The time to the first clinical malaria infection, incidence of malaria episodes, and parasitemia were recorded. Age associated protection from malaria in children with schistosomiasis was observed. SP children (4-8 years of age) compared with SN children demonstrated delayed time to first clinical malaria infection (74 versus 59 days; P = 0.04), fewer numbers of malaria episodes (1.55 versus 1.81 infections; P = 0.03) and lower geometric mean parasite densities (6,359 versus 9,874 asexual forms/mm(3); P = 0.07) at first infection. No association between schistosomiasis and P. falciparum malaria was observed in children 9-14 years of age. We conclude that underlying schistosomiasis is associated with protection against clinical falciparum malaria in an age-dependent manner.     

Polymorphisms in the K13-Propeller Gene in Artemisinin-Susceptible Plasmodium falciparum Parasites from Bougoula-Hameau and Bandiagara,Mali

Artemisinin-resistant Plasmodium falciparum malaria has been documented in southeast Asia and may already be spreading in that region. Molecular markers are important tools for monitoring the spread of antimalarial drug resistance. Recently, single-nucleotide polymorphisms (SNPs) in the PF3D7_1343700 kelch propeller (K13-propeller) domain were shown to be associated with artemisinin resistance in vivo and in vitro. The prevalence and role of K13-propeller mutations are poorly known in sub-Saharan Africa. K13-propeller mutations were genotyped by direct sequencing of nested polymerase chain reaction (PCR) amplicons from dried blood spots of pre-treatment falciparum malaria infections collected before and after the use of artemisinin-based combination therapy (ACT) as first-line therapy in Mali. Although K13-propeller mutations previously associated with delayed parasite clearance in Cambodia were not identified, 26 K13-propeller mutations were identified in both recent samples and pre-ACT infections. Parasite clearance time was comparable between infections with non-synonymous K13-propeller mutations and infections with the reference allele. These findings suggest that K13-propeller mutations are present in artemisinin-sensitive parasites and that they preceded the wide use of ACTs in Mali.     

Optimizing Intradermal Administration of Cryopreserved Plasmodium falciparum Sporozoites in Controlled Human Malaria Infection

Controlled human malaria infection (CHMI) is a powerful tool to evaluate malaria vaccine and prophylactic drug efficacy. Until recently CHMI was only carried out by the bite of infected mosquitoes. A parenteral method of CHMI would standardize Plasmodium falciparum sporozoite (PfSPZ) administration, eliminate the need for expensive challenge facility infrastructure, and allow for use of many P. falciparum strains. Recently, intradermal (ID) injection of aseptic, purified, cryopreserved PfSPZ was shown to induce P. falciparum malaria; however, 100% infection rates were not achieved by ID injection. To optimize ID PfSPZ dosing so as to achieve 100% infection, 30 adults aged 18–45 years were randomized to one of six groups composed of five volunteers each. The parameters of dose (1 × 10⁴ versus 5 × 10⁴ PfSPZ total dose per volunteer), number of injections (two versus eight), and aliquot volume per ID injection (10 μL versus 50 μL) were studied. Three groups attained 100% infection: 1 × 10⁴ PfSPZ in 50 μL/2 doses, 1 × 10⁴ PfSPZ in 10 μL/2 doses, and 5 × 10⁴ PfSPZ in 10 μL/8 doses. The group that received 5 × 10⁴ PfSPZ total dose in eight 10 μL injections had a 100% infection rate and the shortest prepatent period (mean of 12.7 days), approaching the prepatent period for the current CHMI standard of five infected mosquitoes.     

Exploratory factor analysis and validation study of the lifetime severity index for cocaine, Spanish version (LSI-C-Spanish)

The purpose of the study was to do an exploratory factor analysis and to examine the criterion-related and discriminant validity of the Lifetime Severity Index for Cocaine (LSI-C), Spanish version. A sample of 171 outpatients from 10 drug centers in Spain participated in the study. We conducted the factor analysis with orthogonal rotation and examined correlations between the LSI-C total score and criterion variables as well as the score obtained by a quality of life measure. The factor analysis revealed 2 principal factors that explain 65.8% of the variance. Lower LSI-C scores were associated with taking medication, receiving social help, using cocaine fewer than 30 times during the previous 6 months, and with better scores on quality of life measures. Higher LSI-C scores were associated with unstable housing, overdose, hospitalization, cocaine consumption more than 100 times during the previous 6 months, and more years of drug consumption. The LSI-C Spanish version shows acceptable criterion-related and discriminant validity.     

Cell-mediated immunity elicited by the blood stage malaria vaccine apical membrane antigen 1 in Malian adults: Results of a Phase I randomized trial

The development of a safe and effective malaria vaccine is impeded by the complexity of the Plasmodium life cycle. A vaccine that elicits both cell-mediated and humoral immune responses might be needed for protection against this multistage parasitic infection. Apical membrane antigen 1 (AMA-1) plays a key role in erythrocytic invasion but is also expressed in sporozoites and in late stage liver schizonts, where it may provide a target of protective cell-mediated immunity (CMI). A Phase 1 trial of a vaccine consisting of recombinant AMA-1 protein and the Adjuvant system AS02A was conducted in 60 Malian adults aged 18–55 years who were randomized to receive either half-dose (25 μg/0.25 ml) or full dose (50 μg/0.5 ml) FMP2.1/AS02A or a control rabies vaccine. Interleukin 5 (IL-5) and interferon-γ (IFN-γ) production as evaluated by ELISpot and lymphocyte proliferation were measured after in vitro AMA-1 stimulation of peripheral blood mononuclear cells (PBMCs) collected on Days 0 and 90. Post-FMP2.1/AS02A immunization mean stimulation indices were significantly elevated as were the number of IL-5 spot forming cells (SFC)/10⁶ PBMC, but no difference was noted in INF-γ production between the AMA-1/AS02A vaccinated group and the rabies group. These results provide evidence that complex immune responses can be induced by this vaccination strategy and add further impetus for the continuing clinical evaluation of this vaccine.     

The interaction between HIV and malaria in Africa

HIV and malaria kill millions of people every year. They share a common geographic distribution, and both cause far more disease and death in sub-Saharan African than they do in the rest of the world. Many epidemiologic studies have suggested that HIV and malaria coexist independently, but some recent reports describe synergistic interactions between them. People living with HIV infection who do not have pre-existing immunity to malaria experience a marked increase in malaria severity. But for those who have acquired immunity through natural exposure to malaria, HIV-related immunosuppression is associated with only a modest increase in clinical malaria, which may be explained in part by more frequent nonmalaria febrile episodes. The effect of malaria infection on HIV disease progression due to increased viral replication may be important but has not yet been fully explored.     

Kidney outcomes using a sustained ≥40% decline in eGFR: A meta‐analysis of SGLT2 inhibitor trials

BackgroundA recent meta‐analysis of sodium–glucose cotransporter 2 (SGLT2) inhibitor outcome trials reported that SGLT2 inhibitors were associated with reduction in the risk of adverse composite kidney outcomes, with moderate heterogeneity across the trials; however, the endpoints were defined differently across the trials.HypothesisThe apparent heterogeneity of the meta‐analysis of kidney composite outcomes of SGLT2 inhibitor trials will be substantially reduced by using a consistent assessment of sustained ≥40% decline in eGFR/chronic kidney dialysis/transplantation/renal death across trials.MethodsWe performed a meta‐analysis of kidney composite outcomes from the four SGLT2 cardiovascular outcome trial programs conducted in general type 2 diabetes mellitus populations, which included, as a surrogate of progression to kidney failure, a sustained ≥40% decline in eGFR along with kidney replacement therapy and kidney death. The trials assessed were VERTIS CV ({"type":"clinical-trial","attrs":{"text":"NCT01986881","term_id":"NCT01986881"}}NCT01986881), CANVAS Program ({"type":"clinical-trial","attrs":{"text":"NCT01032629","term_id":"NCT01032629"}}NCT01032629 and {"type":"clinical-trial","attrs":{"text":"NCT01989754","term_id":"NCT01989754"}}NCT01989754), DECLARE‐TIMI 58 ({"type":"clinical-trial","attrs":{"text":"NCT01730534","term_id":"NCT01730534"}}NCT01730534), and EMPA‐REG OUTCOME ({"type":"clinical-trial","attrs":{"text":"NCT01131676","term_id":"NCT01131676"}}NCT01131676).ResultsData from the trials comprised 42 516 individual participants; overall, 998 composite kidney events occurred. SGLT2 inhibition was associated with a significant reduction in the kidney composite endpoint (HR 0.58 [95% CI 0.51–0.65]) and with a highly consistent effect across the trials (Q statistic p = .64; I ² = 0.0%).ConclusionsOur meta‐analysis highlights the value of using similarly defined endpoints across trials and supports the finding of consistent protection against kidney disease progression with SGLT2 inhibitors as a class in patients with type 2 diabetes mellitus who either have established atherosclerotic cardiovascular disease or are at high cardiovascular risk with multiple cardiovascular risk factors.     

Genetics of drug-resistant Plasmodium falciparum malaria in the Venezuelan state of Bolivar

The state of Bolivar in Venezuela experiences episodic outbreaks of multidrug-resistant Plasmodium falciparum malaria. We obtained P. falciparum-infected blood samples in Bolivar in 1998-2000, and performed molecular assays for mutations conferring resistance to the antifolate combination of sulfadoxine-pyrimethamine (SP) and to chloroquine. All infections carried the dihydrofolate reductase (dhfr) S108A and N51I mutations, and 45% of the infections had the dhfr C50R mutation, which has been implicated in mid-level resistance to SP. Two dihydropteroate synthase (dhps) mutations also involved in SP resistance, A581G and K540E, were detected in 90% and 67% of the samples, respectively. The dhfr 1164L mutation, which confers high-level resistance, was not identified. The P. falciparum chloroquine resistance transporter (pfcrt) K76T mutation, which is critical for chloroquine resistance, was found in 167 of 168 infections. Six dhfr/dhps allelotypes and four pfcrt-resistant alleles were observed. Their interrelationships suggest a semi-clonal propagation of P. falciparum malaria in Bolivar, and an invasion of multi-resistant pathogens from Brazil. Despite national restrictions on the use of SP and chloroquine, genotypic resistance to these therapies remains widespread in Bolivar.     

Effect of dietary oligofructose and inulin on colonic preneoplastic aberrant crypt foci inhibition

Oligofructose and inulin, naturally-occurring fermentable chicory fructans, have been shown to stimulate the growth of bifidobacteria which are regarded as beneficial strains in the colon and inhibit colon carcinogenesis in the laboratory animal models. The present study was designed to determine the effect of oligofructose and inulin on the azoxymethane (AOM)-induced preneoplastic lesions such as aberrant crypt foci (ACF) formation in the colon of male F344 rats. At 5 weeks of age, groups of animals were fed the AIN-76A (control) and the experimental diets containing 10% oligofructose or inulin. At 7 weeks of age, all animals received s.c. injection of AOM dissolved in normal saline at a dose rate of 15 mg/kg body wt, once weekly for 2 weeks. The animals were necropsied 7 weeks after the last AOM injection, and the ACF were visualized under light microscopy in the formalin-fixed, unsectioned methylene blue-stained colons. They were distinguished by their increased size, more prominent epithelial cells and pericryptal space. The feeding of oligofructose or inulin significantly inhibited the ACF formation and the crypt multiplicity in the colon. The degree of ACF inhibition was more pronounced in animals fed inulin than in those fed oligofructose. The findings suggest that chicory fructan supplements inhibit ACF formation, an early preneoplastic marker of malignant potential in the process of colon carcinogenesis.