Mucosal plasma cells are required to protect the upper airway and brain from infection.

While blood antibodies mediate protective immunity in most organs, whether they protect nasal surfaces in the upper airway is unclear. Using multiple viral infection models in mice, we found that blood-borne antibodies could not defend the olfactory epithelium. Despite high serum antibody titers, pathogens infected nasal turbinates, and neurotropic microbes invaded the brain. Using passive antibody transfers and parabiosis, we identified a restrictive blood-endothelial barrier that excluded circulating antibodies from the olfactory mucosa. Plasma cell depletions demonstrated that plasma cells must reside within olfactory tissue to achieve sterilizing immunity. Antibody blockade and genetically deficient models revealed that this local immunity required CD4+ T cells and CXCR3. Many vaccine adjuvants failed to generate olfactory plasma cells, but mucosal immunizations established humoral protection of the olfactory surface. Our identification of a blood-olfactory barrier and the requirement for tissue-derived antibody has implications for vaccinology, respiratory and CNS pathogen transmission, and B cell fate decisions.

Quality assessment of routine brain imaging at 0.55 T: initial experience in a clinical workflow.

The purpose of this study was to assess the quality of clinical brain imaging in healthy subjects and patients on an FDA-approved commercial 0.55 T MRI scanner, and to provide information about the feasibility of using this scanner in a clinical workflow. In this IRB-approved study, brain examinations on the scanner were prospectively performed in 10 healthy subjects (February-April 2022) and retrospectively derived from 44 patients (February-July 2022). Images collected using the following pulse sequences were available for assessment: axial DWI (diffusion-weighted imaging), apparent diffusion coefficient maps, 2D axial fluid-attenuated inversion recovery images, axial susceptibility-weighted images (both magnitude and phase), sagittal T1 -weighted (T1w) Sampling Perfection with Application Optimized Contrast images, sagittal T1w MPRAGE (magnetization prepared rapid gradient echo) with contrast enhancement, axial T1w turbo spin echo (TSE) with and without contrast enhancement, and axial T2 -weighted TSE. Two readers retrospectively and independently evaluated image quality and specific anatomical features in a blinded fashion on a four-point Likert scale, with a score of 1 being unacceptable and 4 being excellent, and determined the ability to answer the clinical question in patients. For each category of image sequences, the mean, standard deviation, and percentage of unacceptable quality images (<2) were calculated. Acceptable (rating ≥ 2) image quality was achieved at 0.55 T in all sequences for patients and 85% of the sequences for healthy subjects. Radiologists were able to answer the clinical question in all patients scanned. In total, 50% of the sequences used in patients and about 60% of the sequences used in healthy subjects exhibited good (rating ≥ 3) image quality. Based on these findings, we conclude that diagnostic quality clinical brain images can be successfully collected on this commercial 0.55 T scanner, indicating that the routine brain imaging protocol may be deployed on this system in the clinical workflow.

Reduced Accuracy of Intake Screening Questionnaires Tied to Quality Metrics.

Clinical workflows that prioritize repetitive patient intake screening to meet performance metrics may have unintended consequences. This retrospective analysis of electronic health record data from 24 Federally Qualified Health Centers assessed effectiveness and accuracy of the 2-item Patient Health Questionnaire (PHQ-2) for depression screening and Generalized Anxiety Disorder 2 (GAD-2) for anxiety screening from 2019 to 2021. Scores of over 91% of PHQ-2 and GAD-2 tests indicated low likelihood of depression or anxiety, which diverged markedly from published literature on screening outcomes. Visit-based screenings linked to performance metrics may not be delivering the intended value in a real-world setting and risk distracting clinical effort from other high value activities.

Examining How Social Risk Factors Are Integrated Into Clinical Settings Using Existing Data: A Scoping Review.

PURPOSE: Integrating social care into clinical care requires substantial resources. Use of existing data through a geographic information system (GIS) has the potential to support efficient and effective integration of social care into clinical settings. We conducted a scoping literature review characterizing its use in primary care settings to identify and address social risk factors. METHODS: In December 2018, we searched 2 databases and extracted structured data for eligible articles that (1) described the use of GIS in clinical settings to identify and/or intervene on social risks, (2) were published between December 2013 and December 2018, and (3) were based in the United States. Additional studies were identified by examining references. RESULTS: Of the 5,574 articles included for review, 18 met study eligibility criteria: 14 (78%) were descriptive studies, 3 (17%) tested an intervention, and 1 (6%) was a theoretical report. All studies used GIS to identify social risks (increase awareness); 3 studies (17%) described interventions to address social risks, primarily by identifying relevant community resources and aligning clinical services to patients' needs. CONCLUSIONS: Most studies describe associations between GIS and population health outcomes; however, there is a paucity of literature regarding GIS use to identify and address social risk factors in clinical settings. GIS technology may assist health systems seeking to address population health outcomes through alignment and advocacy; its current application in clinical care delivery is infrequent and largely limited to referring patients to local community resources.

A Novel Endocrine Role for the BAT-Released Lipokine 12,13-diHOME to Mediate Cardiac Function.

BACKGROUND: Brown adipose tissue (BAT) is an important tissue for thermogenesis, making it a potential target to decrease the risks of obesity, type 2 diabetes, and cardiovascular disease, and recent studies have also identified BAT as an endocrine organ. Although BAT has been implicated to be protective in cardiovascular disease, to this point there are no studies that identify a direct role for BAT to mediate cardiac function. METHODS: To determine the role of BAT on cardiac function, we utilized a model of BAT transplantation. We then performed lipidomics and identified an increase in the lipokine 12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME). We utilized a mouse model with sustained overexpression of 12,13-diHOME and investigated the role of 12,13-diHOME in a nitric oxide synthase type 1 deficient (NOS1-/-) mouse and in isolated cardiomyocytes to determine effects on function and respiration. We also investigated 12,13-diHOME in a cohort of human patients with heart disease. RESULTS: Here, we determined that transplantation of BAT (+BAT) improves cardiac function via the release of the lipokine 12,13-diHOME. Sustained overexpression of 12,13-diHOME using tissue nanotransfection negated the deleterious effects of a high-fat diet on cardiac function and remodeling, and acute injection of 12,13-diHOME increased cardiac hemodynamics via direct effects on the cardiomyocyte. Furthermore, incubation of cardiomyocytes with 12,13-diHOME increased mitochondrial respiration. The effects of 12,13-diHOME were absent in NOS1-/- mice and cardiomyocytes. We also provide the first evidence that 12,13-diHOME is decreased in human patients with heart disease. CONCLUSIONS: Our results identify an endocrine role for BAT to enhance cardiac function that is mediated by regulation of calcium cycling via 12,13-diHOME and NOS1.

Multicenter Repeatability and Reproducibility of MR Fingerprinting in Phantoms and in Prostatic Tissue.

PURPOSE: To evaluate multicenter repeatability and reproducibility of T1 and T2 maps generated using MR fingerprinting (MRF) in the International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology MRI system phantom and in prostatic tissues. METHODS: MRF experiments were performed on 5 different 3 Tesla MRI scanners at 3 different institutions: University Hospitals Cleveland Medical Center (Cleveland, OH), Brigham and Women's Hospital (Boston, MA) in the United States, and Diagnosticos da America (Rio de Janeiro, RJ) in Brazil. Raw MRF data were reconstructed using a Gadgetron-based MRF online reconstruction pipeline to yield quantitative T1 and T2 maps. The repeatability of T1 and T2 values over 6 measurements in the International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology MRI system phantom was assessed to demonstrate intrascanner variation. The reproducibility between the 4 clinical scanners was assessed to demonstrate interscanner variation. The same-day test-retest normal prostate mean T1 and T2 values from peripheral zone and transitional zone were also compared using the intraclass correlation coefficient and Bland-Altman analysis. RESULTS: The intrascanner variation of values measured using MRF was less than 2% for T1 and 4.7% for T2 for relaxation values, within the range of 307.7 to 2360 ms for T1 and 19.1 to 248.5 ms for T2 . Interscanner measurements showed that the T1 variation was less than 4.9%, and T2 variation was less than 8.1% between multicenter scanners. Both T1 and T2 values in in vivo prostatic tissue demonstrated high test-retest reliability (intraclass correlation coefficient > 0.92) and strong linear correlation (R2  > 0.840). CONCLUSION: Prostate MRF measurements of T1 and T2 are repeatable and reproducible between MRI scanners at different centers on different continents for the above measurement ranges.

Reducing local synthesis of estrogen in the tubular striatum promotes attraction to same-sex odors in female mice.

Brain-derived 17ß-estradiol (E2) confers rapid effects on neural activity. The tubular striatum (TuS, also called the olfactory tubercle) is both capable of local E2 synthesis due to its abundant expression of aromatase and is a critical locus for odor-guided motivated behavior and odor hedonics. TuS neurons also contain mRNA for estrogen receptors α, ß, and the G protein-coupled estrogen receptor. We demonstrate here that mRNA for estrogen receptors appears to be expressed upon TuS dopamine 1 receptor-expressing neurons, suggesting that E2 may play a neuromodulatory role in circuits which are important for motivated behavior. Therefore, we reasoned that E2 in the TuS may influence attraction to urinary odors which are highly attractive. Using whole-body plethysmography, we examined odor-evoked high-frequency sniffing as a measure of odor attaction. Bilateral infusion of the aromatase inhibitor letrozole into the TuS of gonadectomized female adult mice induced a resistance to habituation over successive trials in their investigatory sniffing for female mouse urinary odors, indicative of an enhanced attraction. All males displayed resistance to habituation for female urinary odors, indicative of enhanced attraction that is independent from E2 manipulation. Letrozole's effects were not due to group differences in basal respiration, nor changes in the ability to detect or discriminate between odors (both monomolecular odorants and urinary odors). Therefore, de novo E2 synthesis in the TuS impacts females' but not males' attraction to female urinary odors, suggesting a sex-specific influence of E2 in odor hedonics.

A cluster randomized trial of delivery of intermittent preventive treatment of malaria in pregnancy at the community level in Malawi.

BACKGROUND: Malaria in pregnancy doubles the risk of low birthweight; up to 11% of all neonatal deaths in sub-Saharan Africa are associated with malaria in pregnancy. To prevent these and other adverse health consequences, the World Health Organization recommends administering intermittent preventive treatment in pregnancy (IPTp) with sulfadoxine-pyrimethamine for all pregnant women at each antenatal care (ANC) visit, starting as early as possible in the second trimester. The target is for countries to administer a minimum of three doses (IPTp3+) to at least 85% of pregnant women. METHODS: A cluster randomized, controlled trial was conducted to assess the effect of delivery of IPTp by community health workers on the coverage of IPTp3 + and ANC visits in Malawi. Community delivery of IPTp was implemented within two districts in Malawi over a 21-month period, from November 2018 to July 2020. In control sites, IPTp was delivered at health facilities. Representative samples of women who delivered in the prior 12 months were surveyed at baseline (n = 370, December 2017) and endline (n = 687, August 2020). A difference in differences analysis was conducted to assess the change in coverage of IPTp and ANC over time, accounting for clustering at the health facility level. RESULTS: Overall IPTp coverage increased over the study period. At baseline, women received a mean of 2.3 IPTp doses (range 0-5 doses) across both arms, and at endline, women received a mean of 2.8 doses (range 0-9 doses). Despite overall increases, the change in IPTp3 + coverage was not significantly different between intervention and control groups (6.9%, 95% CI: -5.9%, 19.6%). ANC4 + coverage increased significantly in the intervention group compared with the control group, with a difference-in-differences of 25.3% points (95% CI: 1.3%, 49.3%). CONCLUSIONS: In order to reduce the burden of malaria in pregnancy, new strategies are needed to improve uptake of effective interventions such as IPTp. While community health workers' delivery of IPTp did not increase uptake in this study, they may be effective in other settings or circumstances. Further research can help identify the health systems characteristics that are conducive to community delivery of IPTp and the operational requirements for effective implementation. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03376217. Registered December 6, 2017, https://clinicaltrials.gov/ct2/show/NCT03376217 .

COVID-19 and Gender Differences in Family Medicine Scholarship.

This bibliometric analysis seeks to explore how the COVID-19 pandemic impacted submission rates to Annals of Family Medicine by gender. Women represented 46.3% of all manuscript submissions included in our study (n = 1,964/4,238), spanning from January 1, 2015 to July 15, 2020. The overall volume of submissions increased during COVID-19 in comparison to pre-pandemic months; however, this increase was not evenly distributed among men and women (122% increase vs 101% increase, respectively). In the early months of the pandemic, 244 submissions were authored by men (58.5%), and 173 submissions were authored by women (41.5%). The gap in women's submission rates is troubling, as it suggests they may be at greater risk of falling behind male colleagues during and beyond the COVID-19 pandemic.

Assessing changes in the quality of quantitative health educations research: a perspective from communities of practice.

BACKGROUND: As a community of practice (CoP), medical education depends on its research literature to communicate new knowledge, examine alternative perspectives, and share methodological innovations. As a key route of communication, the medical education CoP must be concerned about the rigor and validity of its research literature, but prior studies have suggested the need to improve medical education research quality. Of concern in the present study is the question of how responsive the medical education research literature is to changes in the CoP. We examine the nature and extent of changes in the quality of medical education research over a decade, using a widely cited study of research quality in the medical education research literature as a benchmark to compare more recent quality indicators. METHODS: A bibliometric analysis was conducted to examine the methodologic quality of quantitative medical education research studies published in 13 selected journals from September 2013 to December 2014. Quality scores were calculated for 482 medical education studies using a 10-item Medical Education Research Study Quality Instrument (MERSQI) that has demonstrated strong validity evidence. These data were compared with data from the original study for the same journals in the period September 2002 to December 2003. Eleven investigators representing 6 academic medical centers reviewed and scored the research studies that met inclusion and exclusion criteria. Primary outcome measures include MERSQI quality indicators for 6 domains: study design, sampling, type of data, validity, data analysis, and outcomes. RESULTS: There were statistically significant improvements in four sub-domain measures: study design, type of data, validity and outcomes. There were no changes in sampling quality or the appropriateness of data analysis methods. There was a small but significant increase in the use of patient outcomes in these studies. CONCLUSIONS: Overall, we judge this as equivocal evidence for the responsiveness of the research literature to changes in the medical education CoP. This study identified areas of strength as well as opportunities for continued development of medical education research.

Differential Responses to Sigma-1 or Sigma-2 Receptor Ablation in Adiposity, Fat Oxidation, and Sexual Dimorphism.

Obesity is increasing at epidemic rates across the US and worldwide, as are its co-morbidities, including type-2 diabetes and cardiovascular disease. Thus, targeted interventions to reduce the prevalence of obesity are of the utmost importance. The sigma-1 receptor (S1R) and sigma-2 receptor (S2R; encoded by Tmem97) belong to the same class of drug-binding sites, yet they are genetically distinct. There are multiple ongoing clinical trials focused on sigma receptors, targeting diseases ranging from Alzheimer's disease through chronic pain to COVID-19. However, little is known regarding their gene-specific role in obesity. In this study, we measured body composition, used a comprehensive laboratory-animal monitoring system, and determined the glucose and insulin tolerance in mice fed a high-fat diet. Compared to Sigmar1+/+ mice of the same sex, the male and female Sigmar1-/- mice had lower fat mass (17% and 12% lower, respectively), and elevated lean mass (16% and 10% higher, respectively), but S1R ablation had no effect on their metabolism. The male Tmem97-/- mice exhibited 7% lower fat mass, 8% higher lean mass, increased volumes of O2 and CO2, a decreased respiratory exchange ratio indicating elevated fatty-acid oxidation, and improved insulin tolerance, compared to the male Tmem97+/+ mice. There were no changes in any of these parameters in the female Tmem97-/- mice. Together, these data indicate that the S1R ablation in male and female mice or the S2R ablation in male mice protects against diet-induced adiposity, and that S2R ablation, but not S1R deletion, improves insulin tolerance and enhances fatty-acid oxidation in male mice. Further mechanistic investigations may lead to translational strategies to target differential S1R/S2R regulations and sexual dimorphism for precision treatments of obesity.

The tubular striatum and nucleus accumbens distinctly represent reward-taking and reward-seeking.

The ventral striatum regulates motivated behaviors that are essential for survival. The ventral striatum contains both the nucleus accumbens (NAc), which is well established to contribute to motivated behavior, and the adjacent tubular striatum (TuS), which is poorly understood in this context. We reasoned that these ventral striatal subregions may be uniquely specialized in their neural representation of goal-directed behavior. To test this, we simultaneously examined TuS and NAc single-unit activity as male mice engaged in a sucrose self-administration task, which included extinction and cue-induced reinstatement sessions. Although background levels of activity were comparable between regions, more TuS neurons were recruited upon reward-taking, and among recruited neurons, TuS neurons displayed greater changes in their firing during reward-taking and extinction than those in the NAc. Conversely, NAc neurons displayed greater changes in their firing during cue-reinstated reward-seeking. Interestingly, at least in the context of this behavioral paradigm, TuS neural activity predicted reward-seeking, whereas NAc activity did not. Together, by directly comparing their dynamics in several behavioral contexts, this work reveals that the NAc and TuS ventral striatum subregions distinctly represent reward-taking and reward-seeking.NEW & NOTEWORTHY The ventral striatum, considered the reward circuitry "hub," is composed of two regions: the NAc, which is well established for its role in reward processing, and the TuS, which has been largely excluded from such studies. This study provides a first step in directly contextualizing the TuS's activity in relation to that in the NAc and, by doing so, establishes a critical framework for future research seeking to better understand the brain basis for drug addiction.

Phospho-ablation of cardiac sodium channel Nav1.5 mitigates susceptibility to atrial fibrillation and improves glucose homeostasis under conditions of diet-induced obesity.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained arrhythmia, with growing evidence identifying obesity as an important risk factor for the development of AF. Although defective atrial myocyte excitability due to stress-induced remodeling of ion channels is commonly observed in the setting of AF, little is known about the mechanistic link between obesity and AF. Recent studies have identified increased cardiac late sodium current (INa,L) downstream of calmodulin-dependent kinase II (CaMKII) activation as an important driver of AF susceptibility. METHODS: Here, we investigated a possible role for CaMKII-dependent INa,L in obesity-induced AF using wild-type (WT) and whole-body knock-in mice that ablates phosphorylation of the Nav1.5 sodium channel and prevents augmentation of the late sodium current (S571A; SA mice). RESULTS: A high-fat diet (HFD) increased susceptibility to arrhythmias in WT mice, while SA mice were protected from this effect. Unexpectedly, SA mice had improved glucose homeostasis and decreased body weight compared to WT mice. However, SA mice also had reduced food consumption compared to WT mice. Controlling for food consumption through pair feeding of WT and SA mice abrogated differences in weight gain and AF inducibility, but not atrial fibrosis, premature atrial contractions or metabolic capacity. CONCLUSIONS: These data demonstrate a novel role for CaMKII-dependent regulation of Nav1.5 in mediating susceptibility to arrhythmias and whole-body metabolism under conditions of diet-induced obesity.

Divergent roles for the RH5 complex components, CyRPA and RIPR in human-infective malaria parasites.

Malaria is caused by Plasmodium parasites, which invade and replicate in erythrocytes. For Plasmodium falciparum, the major cause of severe malaria in humans, a heterotrimeric complex comprised of the secreted parasite proteins, PfCyRPA, PfRIPR and PfRH5 is essential for erythrocyte invasion, mediated by the interaction between PfRH5 and erythrocyte receptor basigin (BSG). However, whilst CyRPA and RIPR are present in most Plasmodium species, RH5 is found only in the small Laverania subgenus. Existence of a complex analogous to PfRH5-PfCyRPA-PfRIPR targeting BSG, and involvement of CyRPA and RIPR in invasion, however, has not been addressed in non-Laverania parasites. Here, we establish that unlike P. falciparum, P. knowlesi and P. vivax do not universally require BSG as a host cell invasion receptor. Although we show that both PkCyRPA and PkRIPR are essential for successful invasion of erythrocytes by P. knowlesi parasites in vitro, neither protein forms a complex with each other or with an RH5-like molecule. Instead, PkRIPR is part of a different trimeric protein complex whereas PkCyRPA appears to function without other parasite binding partners. It therefore appears that in the absence of RH5, outside of the Laverania subgenus, RIPR and CyRPA have different, independent functions crucial for parasite survival.

Diagnostic Yield of Incremental Biopsy Cores and Second Lesion Sampling for In-Gantry MRI-Guided Prostate Biopsy.

BACKGROUND. In-gantry MRI-guided biopsy (MRGB) of the prostate has been shown to be more accurate than other targeted prostate biopsy methods. However, the optimal number of cores to obtain during in-gantry MRGB remains undetermined. OBJECTIVE. The purpose of this study was to assess the diagnostic yield of obtaining an incremental number of cores from the primary lesion and of second lesion sampling during in-gantry MRGB of the prostate. METHODS. This retrospective study included 128 men with 163 prostate lesions who underwent in-gantry MRGB between 2016 and 2019. The men had a total of 163 lesions sampled with two or more cores, 121 lesions sampled with three or more cores, and 52 lesions sampled with four or more cores. A total of 40 men underwent sampling of a second lesion. Upgrade on a given core was defined as a greater International Society of Urological Pathology (ISUP) grade group (GG) relative to the previously obtained cores. Clinically significant prostate cancer (csPCa) was defined as ISUP GG 2 or greater. RESULTS. The frequency of any upgrade was 12.9% (21/163) on core 2 versus 10.7% (13/121) on core 3 (p = .29 relative to core 2) and 1.9% (1/52) on core 4 (p = .03 relative to core 3). The frequency of upgrade to csPCa was 7.4% (12/163) on core 2 versus 4.1% (5/121) on core 3 (p = .13 relative to core 2) and 0% (0/52) on core 4 (p = .07 relative to core 3). The frequency of upgrade on core 2 was higher for anterior lesions (p < .001) and lesions with a higher PI-RADS score (p = .007); the frequency of upgrade on core 3 was higher for apical lesions (p = .01) and lesions with a higher PI-RADS score (p = .01). Sampling of a second lesion resulted in an upgrade in a single patient (2.5%; 1/40); both lesions were PI-RADS category 4 and showed csPCa. CONCLUSION. When performing in-gantry MRGB of the prostate, obtaining three cores from the primary lesion is warranted to optimize csPCa diagnosis. Obtaining a fourth core from the primary lesion or sampling a second lesion has very low yield in upgrading cancer diagnoses. CLINICAL IMPACT. To reduce patient discomfort and procedure times, operators may refrain from obtaining more than three cores or second lesion sampling.

Design of a basigin-mimicking inhibitor targeting the malaria invasion protein RH5.

Many human pathogens use host cell-surface receptors to attach and invade cells. Often, the host-pathogen interaction affinity is low, presenting opportunities to block invasion using a soluble, high-affinity mimic of the host protein. The Plasmodium falciparum reticulocyte-binding protein homolog 5 (RH5) provides an exciting candidate for mimicry: it is highly conserved and its moderate affinity binding to the human receptor basigin (KD ≥1 µM) is an essential step in erythrocyte invasion by this malaria parasite. We used deep mutational scanning of a soluble fragment of human basigin to systematically characterize point mutations that enhance basigin affinity for RH5 and then used Rosetta to design a variant within the sequence space of affinity-enhancing mutations. The resulting seven-mutation design exhibited 1900-fold higher affinity (KD approximately 1 nM) for RH5 with a very slow binding off rate (0.23 h-1 ) and reduced the effective Plasmodium growth-inhibitory concentration by at least 10-fold compared to human basigin. The design provides a favorable starting point for engineering on-rate improvements that are likely to be essential to reach therapeutically effective growth inhibition.

Neurochemical organization of the ventral striatum's olfactory tubercle.

The ventral striatum is a collection of brain structures, including the nucleus accumbens, ventral pallidum and the olfactory tubercle (OT). While much attention has been devoted to the nucleus accumbens, a comprehensive understanding of the ventral striatum and its contributions to neurological diseases requires an appreciation for the complex neurochemical makeup of the ventral striatum's other components. This review summarizes the rich neurochemical composition of the OT, including the neurotransmitters, neuromodulators and hormones present. We also address the receptors and transporters involved in each system as well as their putative functional roles. Finally, we end with briefly reviewing select literature regarding neurochemical changes in the OT in the context of neurological disorders, specifically neurodegenerative disorders. By overviewing the vast literature on the neurochemical composition of the OT, this review will serve to aid future research into the neurobiology of the ventral striatum.

Malaria knowledge and experiences with community health workers among recently pregnant women in Malawi.

BACKGROUND: The World Health Organization recommends three or more doses of intermittent preventive treatment in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP) to mitigate the negative effects of malaria in pregnancy (MIP). Many pregnant women in Malawi are not receiving the recommended number of doses. Community delivery of IPTp (cIPTp) is being piloted as a new approach to increase coverage. This survey assessed recently pregnant women's knowledge of MIP and their experiences with community health workers (CHWs) prior to implementing cIPTp. METHODS: Data were collected via a household survey in Ntcheu and Nkhata Bay Districts, Malawi, from women aged 16-49 years who had a pregnancy resulting in a live birth in the previous 12 months. Survey questions were primarily open response and utilized review of the woman's health passport whenever possible. Analyses accounted for selection weighting and clustering at the health facility level and explored heterogeneity between districts. RESULTS: A total of 370 women were interviewed. Women in both districts found their community health workers (CHWs) to be helpful (77.9%), but only 35.7% spoke with a CHW about antenatal care and 25.8% received assistance for malaria during their most recent pregnancy. A greater proportion of women in Nkhata Bay than Ntcheu reported receiving assistance with malaria from a CHW (42.7% vs 21.9%, p = 0.01); women in Nkhata Bay were more likely to cite IPTp-SP as a way to prevent MIP (41.0% vs 24.8%, p = 0.02) and were more likely to cite mosquito bites as the only way to spread malaria (70.6% vs 62.0% p = 0.03). Women in Nkhata Bay were more likely to receive 3 + doses of IPTp-SP (IPTp3) (59.2% vs 41.8%, p = 0.0002). Adequate knowledge was associated with increased odds of receiving IPTp3, although not statistically significantly so (adjusted odds ratio = 1.50, 95% confidence interval 0.97-2.32, p-value 0.066). CONCLUSIONS: Women reported positive experiences with CHWs, but there was not a focus on MIP. Women in Nkhata Bay were more likely to be assisted by a CHW, had better knowledge, and were more likely to receive IPTp3+ . Increasing CHW focus on the dangers of MIP and implementing cIPTp has the potential to increase IPTp coverage.

Structure of malaria invasion protein RH5 with erythrocyte basigin and blocking antibodies.

Invasion of host erythrocytes is essential to the life cycle of Plasmodium parasites and development of the pathology of malaria. The stages of erythrocyte invasion, including initial contact, apical reorientation, junction formation, and active invagination, are directed by coordinated release of specialized apical organelles and their parasite protein contents. Among these proteins, and central to invasion by all species, are two parasite protein families, the reticulocyte-binding protein homologue (RH) and erythrocyte-binding like proteins, which mediate host-parasite interactions. RH5 from Plasmodium falciparum (PfRH5) is the only member of either family demonstrated to be necessary for erythrocyte invasion in all tested strains, through its interaction with the erythrocyte surface protein basigin (also known as CD147 and EMMPRIN). Antibodies targeting PfRH5 or basigin efficiently block parasite invasion in vitro, making PfRH5 an excellent vaccine candidate. Here we present crystal structures of PfRH5 in complex with basigin and two distinct inhibitory antibodies. PfRH5 adopts a novel fold in which two three-helical bundles come together in a kite-like architecture, presenting binding sites for basigin and inhibitory antibodies at one tip. This provides the first structural insight into erythrocyte binding by the Plasmodium RH protein family and identifies novel inhibitory epitopes to guide design of a new generation of vaccines against the blood-stage parasite.

Plasmodium falciparum erythrocyte-binding antigen 175 triggers a biophysical change in the red blood cell that facilitates invasion.

Invasion of the red blood cell (RBC) by the Plasmodium parasite defines the start of malaria disease pathogenesis. To date, experimental investigations into invasion have focused predominantly on the role of parasite adhesins or signaling pathways and the identity of binding receptors on the red cell surface. A potential role for signaling pathways within the erythrocyte, which might alter red cell biophysical properties to facilitate invasion, has largely been ignored. The parasite erythrocyte-binding antigen 175 (EBA175), a protein required for entry in most parasite strains, plays a key role by binding to glycophorin A (GPA) on the red cell surface, although the function of this binding interaction is unknown. Here, using real-time deformability cytometry and flicker spectroscopy to define biophysical properties of the erythrocyte, we show that EBA175 binding to GPA leads to an increase in the cytoskeletal tension of the red cell and a reduction in the bending modulus of the cell's membrane. We isolate the changes in the cytoskeleton and membrane and show that reduction in the bending modulus is directly correlated with parasite invasion efficiency. These data strongly imply that the malaria parasite primes the erythrocyte surface through its binding antigens, altering the biophysical nature of the target cell and thus reducing a critical energy barrier to invasion. This finding would constitute a major change in our concept of malaria parasite invasion, suggesting it is, in fact, a balance between parasite and host cell physical forces working together to facilitate entry.