Multiparameter Flow Cytometry Analysis of the Human Spleen Applied to Studies of Plasma-Derived EVs From Plasmodium vivax Patients.

The spleen is a secondary lymphoid organ with multiple functions including the removal of senescent red blood cells and the coordination of immune responses against blood-borne pathogens, such as malaria parasites. Despite the major role of the spleen, the study of its function in humans is limited by ethical implications to access human tissues. Here, we employed multiparameter flow cytometry combined with cell purification techniques to determine human spleen cell populations from transplantation donors. Spleen immuno-phenotyping showed that CD45+ cells included B (30%), CD4+ T (16%), CD8+ T (10%), NK (6%) and NKT (2%) lymphocytes. Myeloid cells comprised neutrophils (16%), monocytes (2%) and DCs (0.3%). Erythrocytes represented 70%, reticulocytes 0.7% and hematopoietic stem cells 0.02%. Extracellular vesicles (EVs) are membrane-bound nanoparticles involved in intercellular communication and secreted by almost all cell types. EVs play several roles in malaria that range from modulation of immune responses to vascular alterations. To investigate interactions of plasma-derived EVs from Plasmodium vivax infected patients (PvEVs) with human spleen cells, we used size-exclusion chromatography (SEC) to separate EVs from the bulk of soluble plasma proteins and stained isolated EVs with fluorescent lipophilic dyes. The integrated cellular analysis of the human spleen and the methodology employed here allowed in vitro interaction studies of human spleen cells and EVs that showed an increased proportion of T cells (CD4+ 3 fold and CD8+ 4 fold), monocytes (1.51 fold), B cells (2.3 fold) and erythrocytes (3 fold) interacting with PvEVs as compared to plasma-derived EVs from healthy volunteers (hEVs). Future functional studies of these interactions can contribute to unveil pathophysiological processes involving the spleen in vivax malaria.

Conditional expression of PfAP2-G for controlled massive sexual conversion in Plasmodium falciparum.

Malaria transmission requires that some asexual parasites convert into sexual forms termed gametocytes. The initial stages of sexual development, including sexually committed schizonts and sexual rings, remain poorly characterized, mainly because they are morphologically identical to their asexual counterparts and only a small subset of parasites undergo sexual development. Here, we describe a system for controlled sexual conversion in the human malaria parasite Plasmodium falciparum, based on conditional expression of the PfAP2-G transcription factor. Using this system, ~90 percent of the parasites converted into sexual forms upon induction, enabling the characterization of committed and early sexual stages without further purification. We characterized sexually committed schizonts and sexual rings at the transcriptomic and phenotypic levels, which revealed down-regulation of genes involved in solute transport upon sexual commitment, among other findings. The new inducible lines will facilitate the study of early sexual stages at additional levels, including multiomic characterization and drug susceptibility assays.

Plasma-derived extracellular vesicles from Plasmodium vivax patients signal spleen fibroblasts via NF-kB facilitating parasite cytoadherence.

Plasmodium vivax is the most widely distributed human malaria parasite. Previous studies have shown that circulating microparticles during P. vivax acute attacks are indirectly associated with severity. Extracellular vesicles (EVs) are therefore major components of circulating plasma holding insights into pathological processes. Here, we demonstrate that plasma-derived EVs from Plasmodium vivax patients (PvEVs) are preferentially uptaken by human spleen fibroblasts (hSFs) as compared to the uptake of EVs from healthy individuals. Moreover, this uptake induces specific upregulation of ICAM-1 associated with the translocation of NF-kB to the nucleus. After this uptake, P. vivax-infected reticulocytes obtained from patients show specific adhesion properties to hSFs, reversed by inhibiting NF-kB translocation to the nucleus. Together, these data provide physiological EV-based insights into the mechanisms of human malaria pathology and support the existence of P. vivax-adherent parasite subpopulations in the microvasculature of the human spleen.

Assessment of medium-term cardiovascular disease risk after Japan's 2011 Fukushima Daiichi nuclear accident: a retrospective analysis.

OBJECTIVE: To assess the medium-term indirect impact of the 2011 Fukushima Daiichi nuclear accident on cardiovascular disease (CVD) risks and to identify whether risk factors for CVD changed after the accident. PARTICIPANTS: Residents aged 40 years and over participating in annual public health check-ups from 2009 to 2012, administered by Minamisoma city, located about 10 to 40 km from the Fukushima Daiichi nuclear plant. METHODS: The sex-specific Framingham CVD risk score was considered as the outcome measure and was compared before (2009-2010) and after the accident (2011-2012). A multivariate regression analysis was employed to evaluate risk factors for CVD. RESULTS: Data from 563 individuals (60.2% women) aged 40 to 74 years who participated in the check-ups throughout the study period was analysed. After adjusting for covariates, no statistically significant change was identified in the CVD risk score postaccident in both sexes, which may suggest no obvious medium-term health impact of the Fukushima nuclear accident on CVD risk. The risk factors for CVD and their magnitude and direction (positive/negative) did not change after the accident. CONCLUSIONS: There was no obvious increase in CVD risks in Minamisoma city, which may indicate successful management of health risks associated with CVD in the study sample.

Antiemetic Effectiveness and Cost-Saving of Aprepitant plus Granisetron Is Superior to Palonosetron in Gastrointestinal Cancer Patients Who Received Moderately Emetogenic Chemotherapy.

Purpose The therapeutic benefit of a three-drug combination of antiemetics has not been established in moderately emetogenic chemotherapy (MEC). The aim of this study was to compare the antiemetic effectiveness and cost-saving of palonosetron plus dexamethasone (control group) with aprepitant, granisetron, and dexamethasone (study group) in cancer patients who received MEC. Methods We switched the standard antiemetic treatment from the control group to the study group in gastrointestinal cancer patients who received MEC after October 2015. The antiemetics in both groups were modified using salvage antiemetic therapy at the clinicians' discretion, according to the severity of chemotherapy-induced nausea and vomiting. We retrospectively reviewed the electronic medical records from patients, before and after switching groups, from between April 2014 and March 2016. Results We evaluated 443 treatment courses in 83 patients. The proportion of courses that included salvage antiemetic therapy in the control group and the study group was 34.8 % (116/333) and 8.2 % (9/110), respectively, and was statistically significant (p < 0.001). The mean integrated costs of antiemetics per course in the control group and the study group were 193 ± 55 USD and 143 ± 38 USD, respectively. Multivariate logistic regression analysis revealed that the study group was significantly associated with a reduced risk of requiring salvage antiemetic therapy (p = 0.038). Conclusions These results suggest that the antiemetic effectiveness and cost-saving of a three-drug combination of aprepitant, generic granisetron, and dexamethasone was superior to a two-drug combination of palonosetron plus dexamethasone in gastrointestinal cancer patients who received MEC.

Characterization of natural aryl hydrocarbon receptor agonists from cassia seed and rosemary.

Many recent studies have suggested that activation of the aryl hydrocarbon receptor (AhR) reduces immune responses, thus suppressing allergies and autoimmune diseases. In our continuing study on natural AhR agonists in foods, we examined the influence of 37 health food materials on the AhR using a reporter gene assay, and found that aqueous ethanol extracts of cassia seed and rosemary had particularly high AhR activity. To characterize the AhR-activating substances in these samples, the chemical constituents of the respective extracts were identified. From an active ethyl acetate fraction of the cassia seed extract, eight aromatic compounds were isolated. Among these compounds, aurantio-obtusin, an anthraquinone, elicited marked AhR activation. Chromatographic separation of an active ethyl acetate fraction of the rosemary extract gave nine compounds. Among these compounds, cirsimaritin induced AhR activity at 10-10² µM, and nepitrin and homoplantagenin, which are flavone glucosides, showed marked AhR activation at 10-10³ µM.