A systematic review of the burden of, access to services for and perceptions of patients with overweight and obesity, in humanitarian crisis settings.

INTRODUCTION: Excess body weight causes 4 million deaths annually across the world. The number of people affected by humanitarian crises stands at a record high level with 1 in 95 people being forcibly displaced. These epidemics overlap. Addressing obesity is a post-acute phase activity in non-communicable disease management in humanitarian settings. Information is needed to inform guidelines and timing of interventions. The objective of this review was to explore the prevalence of overweight and obesity in populations directly affected by humanitarian crises; the cascade of care in these populations and perceptions of patients with overweight and obesity. METHODS: Literature searches were carried out in five databases. Grey literature was identified. The population of interest was non-pregnant, civilian adults who had experience of humanitarian crises (armed conflict, complex emergencies and natural disasters). All study types published from January 1st, 2011, were included. Screening, data extraction and quality appraisal were carried out in duplicate. A narrative synthesis is presented. RESULTS: Fifty-six reports from forty-five studies were included. Prevalence estimates varied widely across the studies and by subgroups. Estimates of overweight and obesity combined ranged from 6.4% to 82.8%. Studies were heterogenous. Global distribution was skewed. Increasing adiposity was seen over time, in older adults and in women. Only six studies were at low risk of bias. Body mass index was the predominant measure used. There were no studies reporting cascade of care. No qualitative studies were identified. CONCLUSION: Overweight and obesity varied in crisis affected populations but were rarely absent. Improved reporting of existing data could provide more accurate estimates. Worsening obesity may be prevented by acting earlier in long-term crises and targeting risk groups. The use of waist circumference would provide useful additional information. Gaps remain in understanding the existing cascade of care. Cultural norms around diet and ideal body size vary.

Guidance impact on primary care prescribing rates of simple analgesia: an interrupted time series analysis in England.

BACKGROUND: In March 2018, NHS England published guidance for clinical commissioning groups (CCGs) to encourage implementation of policy to reduce primary care prescriptions of over-the-counter medications, including simple analgesia. AIM: To investigate the impact of guidance publication on prescribing rates of simple analgesia (oral paracetamol, oral ibuprofen, and topical non-steroidal anti-inflammatory drugs) in primary care; CCG guidance implementation intentions; and whether the guidance has created health inequality based on socioeconomic status. DESIGN AND SETTING: Interrupted time series analysis of primary care prescribing data in England. METHOD: Practice-level prescribing data from January 2015 to March 2019 were obtained from NHS Digital. Interrupted time series analyses were used to assess the association of guidance publication with prescribing rates. The association between practice-level prescribing rates and Index of Multiple Deprivation scores before and after publication was quantified using multivariable Poisson regression. Freedom of information requests were submitted to all CCGs. RESULTS: There was a statistically significant 4.4% reduction in prescribing of simple analgesia following guidance publication (adjusted incidence rate ratio 0.96, 95% CI = 0.92 to 0.99, P = 0.027), adjusting for underlying time trend and seasonality. There was considerable diversity across CCGs in whether or how they chose to implement the guidance. Practice-level prescribing rates were greater in more deprived areas. CONCLUSION: Guidance publication was associated with a small reduction in the prescribing rates of simple analgesia across England, without evidence of creating additional health inequality. Careful implementation by CCGs would be required to optimise cost saving to the NHS.

A systematic review of the burden of hypertension, access to services and patient views of hypertension in humanitarian crisis settings.

INTRODUCTION: Globally, a record number of people are affected by humanitarian crises caused by conflict and natural disasters. Many such populations live in settings where epidemiological transition is underway. Following the United Nations high level meeting on non-communicable diseases, the global commitment to Universal Health Coverage and needs expressed by humanitarian agencies, there is increasing effort to develop guidelines for the management of hypertension in humanitarian settings. The objective was to investigate the prevalence and incidence of hypertension in populations directly affected by humanitarian crises; the cascade of care in these populations and patient knowledge of and attitude to hypertension. METHODS: A literature search was carried out in five databases. Grey literature was searched. The population of interest was adult, non-pregnant, civilians living in any country who were directly exposed to a crisis since 1999. Eligibility assessment, data extraction and quality appraisal were carried out in duplicate. RESULTS: Sixty-one studies were included in the narrative synthesis. They reported on a range of crises including the wars in Syria and Iraq, the Great East Japan Earthquake, Hurricane Katrina and Palestinian refugees. There were few studies from Africa or Asia (excluding Japan). The studies predominantly assessed prevalence of hypertension. This varied with geography and age of the population. Access to care, patient understanding and patient views on hypertension were poorly examined. Most of the studies had a high risk of bias due to methods used in the diagnosis of hypertension and in the selection of study populations. CONCLUSION: Hypertension is seen in a range of humanitarian settings and the burden can be considerable. Further studies are needed to accurately estimate prevalence of hypertension in crisis-affected populations throughout the world. An appreciation of patient knowledge and understanding of hypertension as well as the cascade of care would be invaluable in informing service provision.

Adaptation of Plasmodium falciparum to humans involved the loss of an ape-specific erythrocyte invasion ligand.

Plasmodium species are frequently host-specific, but little is currently known about the molecular factors restricting host switching. This is particularly relevant for P. falciparum, the only known human-infective species of the Laverania sub-genus, all other members of which infect African apes. Here we show that all tested P. falciparum isolates contain an inactivating mutation in an erythrocyte invasion associated gene, PfEBA165, the homologues of which are intact in all ape-infective Laverania species. Recombinant EBA165 proteins only bind ape, not human, erythrocytes, and this specificity is due to differences in erythrocyte surface sialic acids. Correction of PfEBA165 inactivating mutations by genome editing yields viable parasites, but is associated with down regulation of both PfEBA165 and an adjacent invasion ligand, which suggests that PfEBA165 expression is incompatible with parasite growth in human erythrocytes. Pseudogenization of PfEBA165 may represent a key step in the emergence and evolution of P. falciparum.

Unravelling the Laverania.

How did an ape-infecting Plasmodium species jump to a human host?

Ape parasite origins of human malaria virulence genes.

Antigens encoded by the var gene family are major virulence factors of the human malaria parasite Plasmodium falciparum, exhibiting enormous intra- and interstrain diversity. Here we use network analysis to show that var architecture and mosaicism are conserved at multiple levels across the Laverania subgenus, based on var-like sequences from eight single-species and three multi-species Plasmodium infections of wild-living or sanctuary African apes. Using select whole-genome amplification, we also find evidence of multi-domain var structure and synteny in Plasmodium gaboni, one of the ape Laverania species most distantly related to P. falciparum, as well as a new class of Duffy-binding-like domains. These findings indicate that the modular genetic architecture and sequence diversity underlying var-mediated host-parasite interactions evolved before the radiation of the Laverania subgenus, long before the emergence of P. falciparum.

A novel multiple-stage antimalarial agent that inhibits protein synthesis.

There is an urgent need for new drugs to treat malaria, with broad therapeutic potential and novel modes of action, to widen the scope of treatment and to overcome emerging drug resistance. Here we describe the discovery of DDD107498, a compound with a potent and novel spectrum of antimalarial activity against multiple life-cycle stages of the Plasmodium parasite, with good pharmacokinetic properties and an acceptable safety profile. DDD107498 demonstrates potential to address a variety of clinical needs, including single-dose treatment, transmission blocking and chemoprotection. DDD107498 was developed from a screening programme against blood-stage malaria parasites; its molecular target has been identified as translation elongation factor 2 (eEF2), which is responsible for the GTP-dependent translocation of the ribosome along messenger RNA, and is essential for protein synthesis. This discovery of eEF2 as a viable antimalarial drug target opens up new possibilities for drug discovery.

Tracking autophagy during proliferation and differentiation of Trypanosoma brucei.

Autophagy is a lysosome-dependent degradation mechanism that sequesters target cargo into autophagosomal vesicles. The Trypanosoma brucei genome contains apparent orthologues of several autophagy-related proteins including an ATG8 family. These ubiquitin-like proteins are required for autophagosome membrane formation, but our studies show that ATG8.3 is atypical. To investigate the function of other ATG proteins, RNAi compatible T. brucei were modified to function as autophagy reporter lines by expressing only either YFP-ATG8.1 or YFP-ATG8.2. In the insect procyclic lifecycle stage, independent RNAi down-regulation of ATG3 or ATG7 generated autophagy-defective mutants and confirmed a pro-survival role for autophagy in the procyclic form nutrient starvation response. Similarly, RNAi depletion of ATG5 or ATG7 in the bloodstream form disrupted autophagy, but did not impede proliferation. Further characterisation showed bloodstream form autophagy mutants retain the capacity to undergo the complex cellular remodelling that occurs during differentiation to the procyclic form and are equally susceptible to dihydroxyacetone-induced cell death as wild type parasites, not supporting a role for autophagy in this cell death mechanism. The RNAi reporter system developed, which also identified TOR1 as a negative regulator controlling YFP-ATG8.2 but not YFP-ATG8.1 autophagosome formation, will enable further targeted analysis of the mechanisms and function of autophagy in the medically relevant bloodstream form of T. brucei.

Plasmodium falciparum ATG8 implicated in both autophagy and apicoplast formation.

Amino acid utilization is important for the growth of the erythrocytic stages of the human malaria parasite Plasmodium falciparum, however the molecular mechanism that permits survival of the parasite during conditions of limiting amino acid supply is poorly understood. We provide data here suggesting that an autophagy pathway functions in P. falciparum despite the absence of a typical lysosome for digestion of the autophagosomes. It involves PfATG8, which has a C-terminal glycine which is absolutely required for association of the protein with autophagosomes. Amino acid starvation provoked increased colocalization between PfATG8- and PfRAB7-labeled vesicles and acidification of the colabeled structures consistent with PfRAB7-mediated maturation of PfATG8-positive autophagosomes; this is a rapid process facilitating parasite survival. Immuno-electron microscopic analyses detected PfRAB7 and PfATG8 on double-membrane-bound vesicles and also near or within the parasite's food vacuole, consistent with autophagosomes fusing with the endosomal system before being routed to the food vacuole for digestion. In nonstarved parasites, PfATG8, but not PfRAB7, was found on the intact apicoplast membrane and on apicoplast-targeted vesicles and apicoplast remnants when the formation of the organelle was disrupted; a localization also requiring the C-terminal glycine. These findings suggest that in addition to a classical role in autophagy, which involves the PfRAB7-endosomal system and food vacuole, PfATG8 is associated with apicoplast-targeted vesicles and the mature apicoplast, and as such contributes to apicoplast formation and maintenance. Thus, PfATG8 may be unique in having such a second role in addition to the formation of autophagosomes required for classical autophagy.

Cell death in parasitic protozoa: regulated or incidental?

Apoptosis and other types of regulated cell death have been defined as fundamental processes in plant and animal development, but the occurrence of, and possible roles for, regulated cell death in parasitic protozoa remain controversial. A key problem has been the difficulty in reconciling the presence of apparent morphological markers of apoptosis and the notable absence of some of the key executioners functioning in higher eukaryotes. Here, we review the evidence for regulated cell death pathways in selected parasitic protozoa and propose that cell death in these organisms be classified into just two primary types: necrosis and incidental death. It is our opinion that dedicated molecular machinery required for the initiation and execution of regulated cell death has yet to be convincingly identified.

Crystal structure of a Trypanosoma brucei metacaspase.

Metacaspases are distantly related caspase-family cysteine peptidases implicated in programmed cell death in plants and lower eukaryotes. They differ significantly from caspases because they are calcium-activated, arginine-specific peptidases that do not require processing or dimerization for activity. To elucidate the basis of these differences and to determine the impact they might have on the control of cell death pathways in lower eukaryotes, the previously undescribed crystal structure of a metacaspase, an inactive mutant of metacaspase 2 (MCA2) from Trypanosoma brucei, has been determined to a resolution of 1.4 Å. The structure comprises a core caspase fold, but with an unusual eight-stranded ß-sheet that stabilizes the protein as a monomer. Essential aspartic acid residues, in the predicted S1 binding pocket, delineate the arginine-specific substrate specificity. In addition, MCA2 possesses an unusual N terminus, which encircles the protein and traverses the catalytic dyad, with Y31 acting as a gatekeeper residue. The calcium-binding site is defined by samarium coordinated by four aspartic acid residues, whereas calcium binding itself induces an allosteric conformational change that could stabilize the active site in a fashion analogous to subunit processing in caspases. Collectively, these data give insights into the mechanistic basis of substrate specificity and mode of activation of MCA2 and provide a detailed framework for understanding the role of metacaspases in cell death pathways of lower eukaryotes.

Trypanosoma brucei metacaspase 4 is a pseudopeptidase and a virulence factor.

Metacaspases are caspase family cysteine peptidases found in plants, fungi, and protozoa but not mammals. Trypanosoma brucei is unusual in having five metacaspases (MCA1-MCA5), of which MCA1 and MCA4 have active site substitutions, making them possible non-enzymatic homologues. Here we demonstrate that recombinant MCA4 lacks detectable peptidase activity despite maintaining a functional peptidase structure. MCA4 is expressed primarily in the bloodstream form of the parasite and associates with the flagellar membrane via dual myristoylation/palmitoylation. Loss of function phenotyping revealed critical roles for MCA4; rapid depletion by RNAi caused lethal disruption to the parasite's cell cycle, yet the generation of MCA4 null mutant parasites (Δmca4) was possible. Δmca4 had normal growth in axenic culture but markedly reduced virulence in mice. Further analysis revealed that MCA4 is released from the parasite and is specifically processed by MCA3, the only metacaspase that is both palmitoylated and enzymatically active. Accordingly, we have identified that the multiple metacaspases in T. brucei form a membrane-associated proteolytic cascade to generate a pseudopeptidase virulence factor.