Human candidate gene polymorphisms and risk of severe malaria in children in Kilifi, Kenya: a case-control association study

Background: Human genetic factors are important determinants of malaria risk. We investigated associations between multiple candidate polymorphisms—many related to the structure or function of red blood cells—and risk for severe Plasmodium falciparum malaria and its specific phenotypes, including cerebral malaria, severe malaria anaemia, and respiratory distress. Methods: We did a case-control study in Kilifi County, Kenya. We recruited as cases children presenting with severe malaria to the high-dependency ward of Kilifi County Hospital. We included as controls infants born in the local community between Aug 1, 2006, and Sept 30, 2010, who were part of a genetics study. We tested for associations between a range of candidate malaria-protective genes and risk for severe malaria and its specific phenotypes. We used a permutation approach to account for multiple comparisons between polymorphisms and severe malaria. We judged p values less than 0·005 significant for the primary analysis of the association between candidate genes and severe malaria. Findings: Between June 11, 1995, and June 12, 2008, 2244 children with severe malaria were recruited to the study, and 3949 infants were included as controls. Overall, 263 (12%) of 2244 children with severe malaria died in hospital, including 196 (16%) of 1233 with cerebral malaria. We investigated 121 polymorphisms in 70 candidate severe malaria-associated genes. We found significant associations between risk for severe malaria overall and polymorphisms in 15 genes or locations, of which most were related to red blood cells: ABO, ATP2B4, ARL14, CD40LG, FREM3, INPP4B, G6PD, HBA (both HBA1 and HBA2), HBB, IL10, LPHN2 (also known as ADGRL2), LOC727982, RPS6KL1, CAND1, and GNAS. Combined, these genetic associations accounted for 5·2% of the variance in risk for developing severe malaria among individuals in the general population. We confirmed established associations between severe malaria and sickle-cell trait (odds ratio [OR] 0·15, 95% CI 0·11–0·20; p=2·61 × 10−58), blood group O (0·74, 0·66–0·82; p=6·26 × 10−8), and –α3·7-thalassaemia (0·83, 0·76–0·90; p=2·06 × 10−6). We also found strong associations between overall risk of severe malaria and polymorphisms in both ATP2B4 (OR 0·76, 95% CI 0·63–0·92; p=0·001) and FREM3 (0·64, 0·53–0·79; p=3·18 × 10−14). The association with FREM3 could be accounted for by linkage disequilibrium with a complex structural mutation within the glycophorin gene region (comprising GYPA, GYPB, and GYPE) that encodes for the rare Dantu blood group antigen. Heterozygosity for Dantu was associated with risk for severe malaria (OR 0·57, 95% CI 0·49–0·68; p=3·22 × 10−11), as was homozygosity (0·26, 0·11–0·62; p=0·002). Interpretation: Both ATP2B4 and the Dantu blood group antigen are associated with the structure and function of red blood cells. ATP2B4 codes for plasma membrane calcium-transporting ATPase 4 (the major calcium pump on red blood cells) and the glycophorins are ligands for parasites to invade red blood cells. Future work should aim at uncovering the mechanisms by which these polymorphisms can result in severe malaria protection and investigate the implications of these associations for wider health. Funding: Wellcome Trust, UK Medical Research Council, European Union, and Foundation for the National Institutes of Health as part of the Bill & Melinda Gates Grand Challenges in Global Health Initiative

European Physician Survey Characterizing the Clinical Pathway and Treatment Patterns of Patients Post-Myocardial Infarction

Introduction: The 2019 European Society of Cardiology and European Atherosclerosis Society (2019 ESC/EAS) guidelines stress the importance of managing low-density lipoprotein cholesterol (LDL-C) after myocardial infarction (MI) to reduce the risk of cardiovascular events. Information on guideline implementation is limited. The aim of this survey was to describe current clinical practice regarding LDL-C management in the first year post-MI across Europe, improving understanding of the role of ESC/EAS guidelines on clinical practice. Methods: A qualitative web-based cross-sectional physician survey about the patient pathway and LDL-C management post-MI was conducted in 360 physicians from France, Italy, Germany, The Netherlands, Spain, and the UK (n = 60/country) between December 2019 and June 2020. Secondary and primary care physicians (SCPs/PCPs) described their experiences treating patients post-MI over the preceding 2months. Results: Physicians reported that on average 90.7% of patients not prescribed lipid-lowering therapy (LLT) before an MI initiated LLT as inpatients; for patients already taking LLT, treatment was intensified for 64.7% of inpatients post-MI. SCPs reported prescribing higher-intensity statins and/or ezetimibe for between 72.3% (Italy) and 88.6% (UK) of patients post-MI. More than 80.0% of SCPs and 51.2% of PCPs stated that they would initiate a change in LLT immediately if patients did not achieve their LDL-C treatment goal by 12weeks post-MI; 82.0% of SCPs and 55.1% of PCPs reported referring to 2019 ESC/EAS guidelines for management of patients post-MI. Barriers to initiating PCSK9 inhibitors (PCSK9is) included prior prescription of a maximally tolerated dose of statin (49.4%) and/or ezetimibe (38.9%), requirement to reach threshold LDL-C levels (44.9%), and pre-authorization requirements (30.4%). Conclusion: Differences in clinical practice post-MI were reported across the countries surveyed, including divergence between 2019 ESC/EAS and local guidelines. Increased use of innovative medicines to achieve LDL-C goals should reduce risk of subsequent cardiovascular events in very high-risk patients post-MI

Malaria Host Candidate Genes Validated by Association With Current, Recent, and Historical Measures of Transmission Intensity

Background: Human malaria susceptibility is determined by multiple genetic factors. It is unclear, however, which genetic variants remain important over time. Methods: Genetic associations of 175 high-quality polymorphisms within several malaria candidate genes were examined in a sample of 8096 individuals from northeast Tanzania using altitude, seroconversion rates, and parasite rates as proxies of historical, recent, and current malaria transmission intensity. A principal component analysis was used to derive 2 alternative measures of overall malaria propensity of a location across different time scales. Results: Common red blood cell polymorphisms (ie, hemoglobin S, glucose-6-phosphate dehydrogenase, and α-thalassemia) were the only ones to be associated with all 3 measures of transmission intensity and the first principal component. Moderate associations were found between some immune response genes (ie, IL3 and IL13) and parasite rates, but these could not be reproduced using the alternative measures of malaria propensity. Conclusions: We have demonstrated the potential of using altitude and seroconversion rate as measures of malaria transmission capturing medium- to long-term time scales to detect genetic associations that are likely to persist over time. These measures also have the advantage of minimizing the deleterious effects of random factors affecting parasite rates on the respective association signals

Development and testing of the BONES physical activity survey for young children

<p>Abstract</p> <p>Background</p> <p>Weight-bearing and high intensity physical activities are particularly beneficial for stimulating bone growth in children given that bone responds favorably to mechanical load. While it is important to assess the contribution and impact of weight-bearing physical activity on health outcomes, measurement tools that quantify and provide information on these activities separately from overall physical activity are limited. This study describes the development and evaluation of a pictorial physical activity survey (PAS) that measures children's participation and knowledge of high-intensity, weight-bearing ("bone smart") physical activity.</p> <p>Methods</p> <p>To test reliability, two identical sets of the PAS were administered on the same day to 41 children (mean age 7.1 ± 0.8 years; 63% female) and compared. To test validity, accelerometry data from 40 children (mean age 7.7 ± 0.8 years; 50% female) were compared to data provided by the PAS. Agreements between categorical and ordinal items were assessed with Kappa statistics; agreements between continuous indices were assessed with Spearman's correlation tests.</p> <p>Results</p> <p>The subjects produced reliable results in all 10 physical activity participation items (κ range: 0.36-0.73, all p < 0.05), but less reliable in answering if the physical activities were "bone smart" (κ range: -0.04-0.66). Physical activity indices, including metabolic equivalent time and weight-bearing factors, were significant in test-retest analyses (Spearman's <it>r </it>range: 0.57-0.74, all p < 0.001). Minutes of very vigorous activity from the accelerometer were associated with the self-reported weight-bearing activity, moderate-high, and high activity scores from the PAS (Spearman's <it>r </it>range: 0.47-0.48, all p < 0.01). However, accelerometer counts, counts per minute, and minutes of moderate-vigorous and vigorous activity were not associated with the PAS scores.</p> <p>Conclusions</p> <p>Together, the results of these studies suggest that the PAS has acceptable test-retest reliability, but limited validity for early elementary school children. This survey demonstrates a first step towards developing a questionnaire that measures high intensity, weight-bearing activity in schoolchildren.</p

PKCα and PKCδ Regulate ADAM17-Mediated Ectodomain Shedding of Heparin Binding-EGF through Separate Pathways

Epidermal growth factor receptor (EGFR) signalling is initiated by the release of EGFR-ligands from membrane-anchored precursors, a process termed ectodomain shedding. This proteolytic event, mainly executed by A Disintegrin And Metalloproteases (ADAMs), is regulated by a number of signal transduction pathways, most notably those involving protein kinase C (PKC). However, the molecular mechanisms of PKC-dependent ectodomain shedding of EGFR-ligands, including the involvement of specific PKC isoforms and possible functional redundancy, are poorly understood. To address this issue, we employed a cell-based system of PMA-induced PKC activation coupled with shedding of heparin binding (HB)-EGF. In agreement with previous studies, we demonstrated that PMA triggers a rapid ADAM17-mediated release of HB-EGF. However, PMA-treatment also results in a protease-independent loss of cell surface HB-EGF. We identified PKCα as the key participant in the activation of ADAM17 and suggest that it acts in parallel with a pathway linking PKCδ and ERK activity. While PKCα specifically regulated PMA-induced shedding, PKCδ and ERK influenced both constitutive and inducible shedding by apparently affecting the level of HB-EGF on the cell surface. Together, these findings indicate the existence of multiple modes of regulation controlling EGFR-ligand availability and subsequent EGFR signal transduction

School's out: what are urban children doing? The Summer Activity Study of Somerville Youth (SASSY)

Background: Research indicates that in the United States, children experience healthier BMI and fitness levels during school vs. summer, but research is limited. The primary goal of this pilot study was to assess where children spend their time during the months that school is not in session and to learn about the different types of activities they engage in within different care settings. A secondary goal of this pilot study was to learn what children eat during the summer months. Methods: A nine-week summer study of 57 parents of second and third grade students was conducted in an economically, racial/ethnically and linguistically diverse US urban city. Weekly telephone interviews queried time and activities spent on/in 1) the main caregiver’s care 2) someone else’s care 3) vacation 4) and camp. Activities were categorised as sedentary, light, moderate, or vigorous (0-3 scale). For each child, a mean activity level was calculated and weighted for proportion of time spent in each care situation, yielding a weighted activity index. On the last phone call, parents answered questions about their child’s diet over the summer. Two post-study focus groups were conducted to help interpret findings from the weekly activity interviews. Results: The mean activity index was 1.05 ± 0.32 and differed between gender (p = 0.07), education (p = 0.08) and primary language spoken in the household (p = 0.01). Children who spent a greater percentage of time in parent care had on average a lower activity index (β = -0.004, p = 0.01) while children who spent a greater percentage of time in camp had a higher activity index (β = 0.004, p = 0.03). When stratified into type of camp, percentage of time spent in active camp was also positively associated with mean activity index (β = 0.005, p =\u3c 0.001). With regards to diet, after adjusting for maternal education, children who attended less than five weeks of camp were four times more likely to eat their meals in front of the TV often/almost all of the time (OR = 4.0, 95%CI 1.0-16.2, p \u3c 0.06). Conclusions: Summer activities and some dietary behaviours are influenced by situation of care and sociodemographic characteristics. In particular, children who spend a greater proportion of time in structured environments appear to be more active. We believe that this pilot study is an important first step in our understanding of what children do during the summer months

Genome variation and population structure among 1142 mosquitoes of the African malaria vector species Anopheles gambiae and Anopheles coluzzii

Mosquito control remains a central pillar of efforts to reduce malaria burden in sub-Saharan Africa. However, insecticide resistance is entrenched in malaria vector populations, and countries with a high malaria burden face a daunting challenge to sustain malaria control with a limited set of surveillance and intervention tools. Here we report on the second phase of a project to build an open resource of high-quality data on genome variation among natural populations of the major African malaria vector species Anopheles gambiae and Anopheles coluzzii. We analyzed whole genomes of 1142 individual mosquitoes sampled from the wild in 13 African countries, as well as a further 234 individuals comprising parents and progeny of 11 laboratory crosses. The data resource includes high-confidence single-nucleotide polymorphism (SNP) calls at 57 million variable sites, genome-wide copy number variation (CNV) calls, and haplotypes phased at biallelic SNPs. We use these data to analyze genetic population structure and characterize genetic diversity within and between populations. We illustrate the utility of these data by investigating species differences in isolation by distance, genetic variation within proposed gene drive target sequences, and patterns of resistance to pyrethroid insecticides. This data resource provides a foundation for developing new operational systems for molecular surveillance and for accelerating research and development of new vector control tools. It also provides a unique resource for the study of population genomics and evolutionary biology in eukaryotic species with high levels of genetic diversity under strong anthropogenic evolutionary pressures

Host candidate gene polymorphisms and clearance of drug-resistant Plasmodium falciparum parasites

Resistance to anti-malarial drugs is a widespread problem for control programmes for this devastating disease. Molecular tests are available for many anti-malarial drugs and are useful tools for the surveillance of drug resistance. However, the correlation of treatment outcome and molecular tests with particular parasite markers is not perfect, due in part to individuals who are able to clear genotypically drug-resistant parasites. This study aimed to identify molecular markers in the human genome that correlate with the clearance of malaria parasites after drug treatment, despite the drug resistance profile of the protozoan as predicted by molecular approaches