Retention of uninfected red blood cells causing congestive splenomegaly is the major mechanism of anemia in malaria.

Splenomegaly frequently occurs in patients with Plasmodium falciparum (Pf) or P. vivax (Pv) malarial anemia, but mechanisms underlying this co-occurrence are unclear. In malaria-endemic Papua, Indonesia, we prospectively analyzed red blood cell (RBC) concentrations in the spleen and spleen-mimetic retention in 37 subjects splenectomized for trauma or hyperreactive splenomegaly, most of whom were infected with Plasmodium. Splenomegaly (median 357 g [range: 80-1918 g]) was correlated positively with the proportion of red-pulp on histological sections (median 88.1% [range: 74%-99.4%]; r = .59, p = .0003) and correlated negatively with the proportion of white-pulp (median 8.3% [range: 0.4%-22.9%]; r = -.50, p = .002). The number of RBC per microscopic field (>95% uninfected) was correlated positively with spleen weight in both Pf-infected (r = .73; p = .017) and Pv-infected spleens (r = .94; p = .006). The median estimated proportion of total-body RBCs retained in Pf-infected spleens was 8.2% (range: 1.0%-33.6%), significantly higher than in Pv-infected (2.6% [range: 0.6%-23.8%]; p = .015) and PCR-negative subjects (2.5% [range: 1.0%-3.3%]; p = .006). Retained RBCs accounted for over half of circulating RBC loss seen in Pf infections. The proportion of total-body RBC retained in Pf- and Pv-infected spleens correlated negatively with hemoglobin concentrations (r = -.56, p = .0003), hematocrit (r = -.58, p = .0002), and circulating RBC counts (r = -.56, p = .0003). Splenic CD71-positive reticulocyte concentrations correlated with spleen weight in Pf (r = 1.0; p = .003). Retention rates of peripheral and splenic RBCs were correlated negatively with circulating RBC counts (r = -.69, p = .07 and r = -.83, p = .008, respectively). In conclusion, retention of mostly uninfected RBC in the spleen, leading to marked congestion of the red-pulp, was associated with splenomegaly and is the major mechanism of anemia in subjects infected with Plasmodium, particularly Pf.

Safe drugs with high potential to block malaria transmission revealed by a spleen-mimetic screening.

Malaria parasites like Plasmodium falciparum multiply in red blood cells (RBC), which are cleared from the bloodstream by the spleen when their deformability is altered. Drug-induced stiffening of Plasmodium falciparum-infected RBC should therefore induce their elimination from the bloodstream. Here, based on this original mechanical approach, we identify safe drugs with strong potential to block the malaria transmission. By screening 13 555 compounds with spleen-mimetic microfilters, we identified 82 that target circulating transmissible form of P. falciparum. NITD609, an orally administered PfATPase inhibitor with known effects on P. falciparum, killed and stiffened transmission stages in vitro at nanomolar concentrations. Short exposures to TD-6450, an orally-administered NS5A hepatitis C virus inhibitor, stiffened transmission parasite stages and killed asexual stages in vitro at high nanomolar concentrations. A Phase 1 study in humans with a primary safety outcome and a secondary pharmacokinetics outcome ( https://clinicaltrials.gov , ID: NCT02022306) showed no severe adverse events either with single or multiple doses. Pharmacokinetic modelling showed that these concentrations can be reached in the plasma of subjects receiving short courses of TD-6450. This physiologically relevant screen identified multiple mechanisms of action, and safe drugs with strong potential as malaria transmission-blocking agents which could be rapidly tested in clinical trials.

Microfluidic study of retention and elimination of abnormal red blood cells by human spleen with implications for sickle cell disease.

The spleen clears altered red blood cells (RBCs) from circulation, contributing to the balance between RBC formation (erythropoiesis) and removal. The splenic RBC retention and elimination occur predominantly in open circulation where RBCs flow through macrophages and inter-endothelial slits (IESs). The mechanisms underlying and interconnecting these processes significantly impact clinical outcomes. In sickle cell disease (SCD), blockage of intrasplenic sickled RBCs is observed in infants splenectomized due to acute splenic sequestration crisis (ASSC). This life-threatening RBC pooling and organ swelling event is plausibly triggered or enhanced by intra-tissular hypoxia. We present an oxygen-mediated spleen-on-a-chip platform for in vitro investigations of the homeostatic balance in the spleen. To demonstrate and validate the benefits of this general microfluidic platform, we focus on SCD and study the effects of hypoxia on splenic RBC retention and elimination. We observe that RBC retention by IESs and RBC-macrophage adhesion are faster in blood samples from SCD patients than those from healthy subjects. This difference is markedly exacerbated under hypoxia. Moreover, the sickled RBCs under hypoxia show distinctly different phagocytosis processes from those non-sickled RBCs under hypoxia or normoxia. We find that reoxygenation significantly alleviates RBC retention at IESs, and leads to rapid unsickling and fragmentation of the ingested sickled RBCs inside macrophages. These results provide unique mechanistic insights into how the spleen maintains its homeostatic balance between splenic RBC retention and elimination, and shed light on how disruptions in this balance could lead to anemia, splenomegaly, and ASSC in SCD and possible clinical manifestations in other hematologic diseases.

[Risk factors and management of uterine rupture in a 1st reference structure in Mali: case of the Bougouni health district]. / Facteurs de risque et prise en charge de la rupture uterine dans une structure de 1ere reference du Mali : cas du district sanitaire de Bougouni.

The objective was to assess the risk factors for and to suggest therapeutic aspects. MATERIALS AND METHODS: We carried out a case-control study at the Bougouni Reference health center in 2019. RESULTS: From January to December 31, 2019; out of 1161 deliveries, 43 uterine rupture were recorded, 3.7% corresponding to one uterine rupture for 27 deliveries. Patients 35 years and older were more affected by uterine rupture (44.2%) with ORaIC95% = 6.3 [1.5 - 26.3]. Obstetric evacuations had an ORaIC95% = 25.6 [7.8-83.7]. All of the patients were housewives (97.7%) versus (82.3%) controls with ORaIC95% = 8.9 (1.1-69). Pauciparous and multiparous had an ORaIC95% = 6.2 [1.8 - 20.3] and 4.1 [1.3 - 12.9], respectively. The uterine scar (20.9%) of cases versus 8.1% of controls had a 95% ORaIC95% = 2.9 [1.1 - 8.7]. Indeed the absence of ANC was a risk factor, ORaIC95% = 3.0 [1.3 - 6.9]. The time to uterine rupture was < 6 hours in 95%. In fact 34 complete uterine rupture (79.1%) and 9 incomplete uterine rupture (20.9) were noted. Only 2.3% of cases gave birth vaginally. Treatment of uterine rupture was based on surgery (100%) supplemented by shock (51.2%) of cases and infection (100%) of cases. CONCLUSION: Uterine rupture is common in our countries under medical care. Its effective prevention involves strategies aimed at acting on risk factors.

L'objectif était d'évaluer les facteurs de risque de la RU et de proposer les aspects thérapeutiques. MATÉRIELS ET MÉTHODES: Nous avons réalisé une étude cas-témoins au centre de santé de Référence de Bougouni en 2019. RÉSULTATS: De janvier au 31 décembre 2019 ; sur 1161 accouchements 43 RU ont été enregistrées soit 3,7% correspondant à une RU pour 27 accouchements. Les patientes de 35 ans et plus ont été plus touchée par la RU (44,2%) avec ORaIC95%= 6,3 [1,5 - 26,3]. Les évacuations obstétricales avaient un ORaIC95%=25,6 [7,8- 83,7]. La totalité des patientes étaient des femmes au foyer (97,7%) des cas versus (82,3%) des témoins avec ORaIC95%=8,9 (1,1-69). Les Paucipares et multipares avaient respectivement un ORaIC95%= 6,2 [1,8 - 20,3] et 4,1[1,3 - 12,9]. La cicatrice utérine (20,9%) des cas contre 8,1 % les témoins avait un ORaIC95%= 2,9 [1,1 - 8,7]. En effet l'absence de CPN étaient un facteur de risque, ORaIC95%= 3,0 [1,3 ­ 6,9]. Le délai de la RU était < 6 heures chez 95%. En effet 34 RU complètes (79,1%) et 9 RU incomplètes (20,9%) ont été notées. Seulement 2,3 % des cas avaient accouché par voie basse. Le traitement de la RU reposait sur la chirurgie (100%) complétée par celui du choc (51,2%) des cas et de l'infection (100%) des cas. CONCLUSION: La RU est fréquente dans nos pays sous médicalisés. Sa prévention efficace passe par des stratégies visant à agir sur les facteurs de risque.

A population-based combination strategy to improve the cervical cancer screening coverage rate in Bamako, Mali.

INTRODUCTION: Cervical cancer screening coverage rate is <5% in Sub-Saharan Africa and <2% in French- speaking African countries. In 2016, we implemented strategies to improve cervical cancer screening in Bamako, the "Weekend70 program". The present study objectives are to determine the effect of this program on women's participation in cervical cancer screening in Bamako, and to estimate the cervical cancer screening coverage rate in Bamako. MATERIAL AND METHODS: From 1 January 2016 to 31 July 2020, we conducted an operational research by developing several strategies to improve the cervical cancer screening coverage rate among adolescents and women ≥15 years old in Bamako, Mali. The strategies consisted of awareness-raising activities, strengthening of screening practices in healthcare facilities and cost-free cervical cancer screening during the weekend. Descriptive statistics were presented. The cervical cancer coverage rate was calculated by dividing the number of women screened by the total number of women ≥20 years old, based on Mali demographic data. RESULTS: The total number of women screened was 289 924. Residents from Bamako represented 91.9% (266 436/289 924) vs 8.1% (23 488/289 924) who lived outside Bamako. The mean age was 33.2 (± 11.5) years old. Around 46.1% of participants attending the cervical cancer screening were between 30 and 49 years old (World Health Organization prioritized target age for cervical cancer screening). Women ≥60 years old represented <5%. Cervical cancer screening participation increased significantly, from <800 women screened per week before the implementation of the program to a peak of 4100 women screened per week during the "Weekend70 program". Overall, the cervical cancer screening coverage rates at the end of the study among women ≥20 years old was 47.3%, and 56.9% in the WHO target population. CONCLUSION: In an impoverished context, a multi-component strategy significantly increases cervical cancer screening participation.

Plasmodium falciparum sexual parasites regulate infected erythrocyte permeability.

To ensure the transport of nutrients necessary for their survival, Plasmodium falciparum parasites increase erythrocyte permeability to diverse solutes. These new permeation pathways (NPPs) have been extensively characterized in the pathogenic asexual parasite stages, however the existence of NPPs has never been investigated in gametocytes, the sexual stages responsible for transmission to mosquitoes. Here, we show that NPPs are still active in erythrocytes infected with immature gametocytes and that this activity declines along gametocyte maturation. Our results indicate that NPPs are regulated by cyclic AMP (cAMP) signaling cascade, and that the decrease in cAMP levels in mature stages results in a slowdown of NPP activity. We also show that NPPs facilitate the uptake of artemisinin derivatives and that phosphodiesterase (PDE) inhibitors can reactivate NPPs and increase drug uptake in mature gametocytes. These processes are predicted to play a key role in P. falciparum gametocyte biology and susceptibility to antimalarials.

A Chemically Stable Fluorescent Mimic of Dihydroartemisinin, Artemether, and Arteether with Conserved Bioactivity and Specificity Shows High Pharmacological Relevance to the Antimalarial Drugs.

Three novel tracers designed as fluorescent surrogates of artemisinin-derived antimalarial drugs (i.e., dihydroartemisinin, artemether, arteether, and artemisone) were synthesized from dihydroartemisinin. One of these tracers, corresponding to a dihydroartemisinin/artemether/arteether mimic, showed a combination of excellent physicochemical and biological properties such as hydrolytic stability, high inhibitory potency against blood-stage parasites, similar ring-stage survival assay values than the clinical antimalarials, high cytopermeability and specific labeling of live P. falciparum cells, alkylation of heme, as well as specific covalent labeling of drug-sensitive and drug-resistant P. falciparum proteomes at physiological concentrations, consistent with a multitarget action of the drugs. Our study demonstrates that probes containing the complete structural core of clinical artemisinin derivatives can be stable in biochemical and cellular settings, and recapitulate the complex mechanisms of these frontline, yet threatened, antimalarial drugs.

Artemisinin and its derivatives target mitochondrial c-type cytochromes in yeast and human cells.

Artemisinin and its derivatives kill malaria parasites and inhibit the proliferation of cancer cells. In both processes, heme was shown to play a key role in artemisinin bioactivation. We found that artemisinin and clinical artemisinin derivatives are able to compensate for a mutation in the yeast Bcs1 protein, a key chaperon involved in biogenesis of the mitochondrial respiratory complex III. The equivalent Bcs1 variant causes an encephalopathy in human by affecting complex III assembly. We show that artemisinin derivatives decrease the content of mitochondrial cytochromes and disturb the maturation of the complex III cytochrome c1. This last effect is likely responsible for the compensation by decreasing the detrimental over-accumulation of the inactive pre-complex III observed in the bcs1 mutant. We further show that a fluorescent dihydroartemisinin probe rapidly accumulates in the mitochondrial network and targets cytochromes c and c1 in yeast, human cells and isolated mitochondria. In vitro this probe interacts with purified cytochrome c only under reducing conditions and we detect cytochrome c-dihydroartemisinin covalent adducts by mass spectrometry analyses. We propose that reduced mitochondrial c-type cytochromes act as both targets and mediators of artemisinin bioactivation in yeast and human cells.

A neurodevelopmental TUBB2B ß-tubulin mutation impairs Bim1 (yeast EB1)-dependent spindle positioning.

Malformations of the human cerebral cortex can be caused by mutations in tubulins that associate to compose microtubules. Cerebral cortical folding relies on neuronal migration and on progenitor proliferation partly dictated by microtubule-dependent mitotic spindle positioning. A single amino acid change, F265L, in the conserved TUBB2B ß-tubulin gene has been identified in patients with abnormal cortex formation. A caveat for studying this mutation in mammalian cells is that nine genes encode ß-tubulin in human. Here, we generate a yeast strain expressing F265L tubulin mutant as the sole source of ß-tubulin. The F265L mutation does not preclude expression of a stable ß-tubulin protein which is incorporated into microtubules. However, impaired cell growth was observed at high temperatures along with altered microtubule dynamics and stability. In addition, F265L mutation produces a highly specific mitotic spindle positioning defect related to Bim1 (yeast EB1) dysfunction. Indeed, F265L cells display an abnormal Bim1 recruitment profile at microtubule plus-ends. These results indicate that the F265L ß-tubulin mutation affects microtubule plus-end complexes known to be important for microtubule dynamics and for microtubule function during mitotic spindle positioning.

Prevalence of HPV 16 and 18 and attitudes toward HPV vaccination trials in patients with cervical cancer in Mali.

BACKGROUND: Cervical cancer is one of the most common and lethal cancers in West Africa. Even though vaccines that protect against the most common Human papillomavirus (HPV) strains, 16 and 18, are currently in use in developed countries, the implementation of these vaccines in developing countries has been painfully slow, considering the pre-eminence of HPV-associated cervical cancer among women in those countries. AIM: We performed serological and PCR-based assessment of blood and tissue specimens obtained from women undergoing cervical cancer-related surgery at a major urban hospital in Bamako. Since several therapeutic HPV vaccines are currently in clinical trials, we also assessed willingness to participate in HPV cancer vaccine trials. METHODS: Blood and biopsy samples of 240 women were evaluated for HPV types 16 and 18 by serology and PCR. Knowledge regarding the HPV vaccine and autonomy to decide to vaccinate their own child was assessed with a standardized questionnaire. RESULTS: HPV 16 and 18 were identified in 137/166 (82.5%) cervical cancer biopsy samples by PCR. Co-infection with both HPV 16 and 18 was significantly more frequent in women over 50 years of age than in younger women (63.0% vs. 37.0%). 44% of study participants said they would be willing to vaccinate their child with HPV vaccine. Only 39% of women participating in this study reported that they would be able to make an autonomous decision to receive HPV vaccination. Permission from a male spouse or head of household was identified as important for participation by 59% of the women. CONCLUSION: This study provides strong support for the introduction of currently available HPV vaccines in Mali, and also provides key information about conditions for obtaining informed consent for HPV vaccine trials and HPV vaccination in Mali.