Trends of atropinic (anticholinergic) exposure in the elderly: a 10‐year analysis in the French EGB database

Atropinic drugs are known to potentially induce physical and/or mental impairments in the elderly. The aim of this study was to investigate trends of atropinic exposure in patients ≥65 years in France between 2006 and 2015. A repeated cross‐sectional study was performed quarterly from January 1, 2006 to December 31, 2015, in the ‘Echantillon Généraliste des Bénéficiaires (EGB)’, a representative sample of the French population. Exposed patients were identified using the Anticholinergic Durán's list. Outcomes were rate of patients exposed to at least one atropinic drug (atropinic prevalence rate) and atropinic burden per patient (sum of atropinic burden scores). Interrupted time series were used to analyze the impact of market withdrawal of some drugs with atropinic properties during the period of the study. The number of patients ≥65 years registered in the EGB ranged from 75 611 in 2006 to 95 389 in 2015. Atropinic prevalence rate decreased significantly from 45.6% in 2006 to 33.2% in 2015 (?12.4%, slope significance P < 0.05). Subjects aged ≥85 years were the most exposed. Total atropinic burden decreased significantly between 2006 and 2015 (2.2 ± 1.7 in 2006; 2.0 ± 1.5 in 2015; slope significance P < 0.05), especially in patients ≥85 years. Market withdrawals for safety reasons of some atropinic drugs were significantly associated with a decrease in the atropinic prevalence rate (P < 0.05) and atropinic burden per patient (P < 0.05). In conclusion, atropinic drug exposure in the elderly significantly decreased in France between 2006 and 2015. This decrease can be partly explained by regulatory measures against some atropinic drugs.     

Comparison between olanzapine and haloperidol on procedural learning and the relationship with striatal D2 receptor occupancy in schizophrenia

The striatum is known to play a primary role in procedural learning. In this study, the authors simultaneously assessed the effects of two antipsychotic drugs on procedural learning and on striatal dopamine (D2) receptor occupancy. Twenty-seven patients receiving either olanzapine or haloperidol as antipsychotic medication were assessed with the Computed Visual Tracking Task (CVTT) and Single Photon Emission Computed Tomography (SPECT) following the administration of Iodine 123-IBZM (123I-IBZM), a radioligand with a high affinity and specificity for the D2 receptors. The results showed poorer procedural learning in the haloperidol-treated patients than in normal control subjects, while no difference could be found between olanzapine-treated patients and normal control subjects. In the haloperidol but not the olanzapine group, significant correlations were found between procedural learning deficits and striatal D2 receptor occupancy. However, there was no significant difference in D2 receptor occupancy between olanzapine- and haloperidol-treated patients, and this may be related to the high doses of olanzapine and low doses of haloperidol administered. The authors concluded that: 1) striatal D2 receptor blockade may alter procedural learning in humans; and 2) olanzapine may have a protective effect on procedural learning, even at doses that produce striatal D2 receptor occupancy as high as that found with haloperidol. This protective effect of olanzapine may be related to its atypical pharmacological properties.     

Dissecting the interface between apicomplexan parasite and host cell: Insights from a divergent AMA–RON2 pair

Plasmodium falciparum and Toxoplasma gondii are widely studied parasites in phylum Apicomplexa and the etiological agents of severe human malaria and toxoplasmosis, respectively. These intracellular pathogens have evolved a sophisticated invasion strategy that relies on delivery of proteins into the host cell, where parasite-derived rhoptry neck protein 2 (RON2) family members localize to the host outer membrane and serve as ligands for apical membrane antigen (AMA) family surface proteins displayed on the parasite. Recently, we showed that T. gondii harbors a novel AMA designated as TgAMA4 that shows extreme sequence divergence from all characterized AMA family members. Here we show that sporozoite-expressed TgAMA4 clusters in a distinct phylogenetic clade with Plasmodium merozoite apical erythrocyte-binding ligand (MAEBL) proteins and forms a high-affinity, functional complex with its coevolved partner, TgRON2_L1. High-resolution crystal structures of TgAMA4 in the apo and TgRON2_L1-bound forms complemented with alanine scanning mutagenesis data reveal an unexpected architecture and assembly mechanism relative to previously characterized AMA–RON2 complexes. Principally, TgAMA4 lacks both a deep surface groove and a key surface loop that have been established to govern RON2 ligand binding selectivity in other AMAs. Our study reveals a previously underappreciated level of molecular diversity at the parasite–host-cell interface and offers intriguing insight into the adaptation strategies underlying sporozoite invasion. Moreover, our data offer the potential for improved design of neutralizing therapeutics targeting a broad range of AMA–RON2 pairs and apicomplexan invasive stages.Phylum Apicomplexa comprises >5,000 parasitic protozoan species, many of which cause devastating diseases on a global scale. Two of the most prevalent species are Toxoplasma gondii and Plasmodium falciparum, the causative agents of toxoplasmosis and severe human malaria, respectively (1, 2). The obligate intracellular apicomplexan parasites lead complex and diverse lifestyles that require invasion of many different cell types. Despite this diversity of target host cells, most apicomplexans maintain a generally conserved mechanism for active invasion (3). The parasite initially glides over the surface of a host cell and then reorients to place its apical end in close contact to the host-cell membrane. After this initial attachment, a circumferential ring of adhesion (termed the moving or tight junction) is formed, through which the parasite actively propels itself while concurrently depressing the host-cell membrane to create a nascent protective vacuole (4).Formation of the moving junction relies on a pair of highly conserved parasite proteins: rhoptry neck protein 2 (RON2) and apical membrane antigen 1 (AMA1). Initially, parasites discharge RON2 into the host cell membrane where an extracellular portion (domain 3; D3) serves as a ligand for AMA1 displayed on the parasite surface (5–8). Intriguingly, recent studies have shown that the AMA1–RON2 complex is an attractive target for therapeutic intervention (9–12). The importance of the AMA1–RON2 pairing is also reflected in the observation that many apicomplexan parasites encode functional paralogs that are generally expressed in a stage-specific manner (13–15). We recently showed that, in addition to AMA1 and RON2, T. gondii harbors three additional AMA paralogs and two additional RON2 paralogs (14, 15): TgAMA2 forms a functional invasion complex with TgRON2 (15), TgAMA3 (also annotated as SporoAMA1) selectively coordinates TgRON2_L2 (14), and TgAMA4 binds TgRON2_L1 (15). Despite substantial sequence divergence, structural characterization of all AMA–RON2D3 complexes solved to date [TgAMA1–TgRON2D3 (16), PfAMA1–PfRON2D3 (17), and TgAMA3–TgRON2_L2D3 (14)] reveal a largely conserved architecture and binding paradigm. Intriguingly, however, sequence analysis indicates that TgAMA4 and TgRON2_L1 are likely to adopt substantially divergent structures with an atypical assembly mechanism.To investigate the functional implications of the AMA4–RON2_L1 complex in T. gondii, we first established that TgAMA4 is part of a highly divergent AMA clade that includes the functionally important malaria vaccine candidate Plasmodium merozoite apical erythrocyte-binding ligand (MAEBL) (18–20) and that TgRON2_L1 displays a similar divergence consistent with coevolution of receptor and ligand. We then show that TgAMA4 and TgRON2_L1 form a high-affinity binary complex and probe its overall architecture and underlying mechanism of assembly using crystal structures of TgAMA4 in the apo and TgRON2_L1D3 bound forms. Finally, we show proof of principle that TgAMA4 and TgRON2_L1 form a functional pairing capable of supporting host-cell invasion. Collectively, our study reveals exceptional molecular diversity at the parasite–host-cell interface that we discuss in the context of the unique invasion barriers encountered by the sporozoite.     

The genetics of familial adenomatous polyposis (FAP) and MutYH-associated polyposis (MAP)

FAP is characterized by 100-1000s of adenomatous polyps in colon and rectum, and is in 70% of the patients associated with extracolonic manifestations. Attenuated FAP (AFAP) is a less severe form of FAP, marked by the presence of < 100 polyps and a later onset of colorectal cancer (CRC). (A)FAP is caused by autosomal dominantly inherited mutations in the APC (Adenomatous polyposis coli) gene, a tumour suppressor gene that controls beta-catenin turnover in the Wnt pathway. De novo occurrence is reported in 30-40% of the patients. Mutations are detected in 85% of classical FAP families, while only 20%-30% of AFAP cases will exhibit a germline APC mutation. MUTYH is the second (A)FAP-related gene and is involved with base-excision repair of DNA damaged by oxidative stress. MUTYH mutations are inherited in an autosomal recessive way and account for 10%-20% of classical FAP cases without an APC mutation and for 30% of AFAP cases. Genotype-phenotype correlations exist for mutations in the APC gene, however, contradictions in the literature caution against the sole use of the genotype for decisions regarding clinical management. Once the family's specific APC mutation is identified in the proband, predictive testing for first degree relatives is possible from the age of 10 to 12 years on. For AFAP, relatives are tested at age 18 and older. Opinions about the appropriate ages at which to initiate genetic testing may vary. Physicians must have a discussion about prenatal testing with patients in childbearing age. They may either opt for conventional prenatal diagnosis (amniocentesis or chorionic villous sampling) or for preimplantation genetic diagnosis (PGD).     

Lactoferrin inhibits the lipopolysaccharide-induced expression and proteoglycan-binding ability of interleukin-8 in human endothelial cells

Interleukin-8 (IL-8), a C-X-C chemokine bound to endothelium proteoglycans, initiates the activation and selective recruitment of leukocytes at inflammatory foci. We demonstrate that human lactoferrin, an antimicrobial lipopolysaccharide (LPS)-binding protein, decreases both IL-8 mRNA and protein expression induced by the complex Escherichia coli 055:B5 LPS/sCD14 in human umbilical vein endothelial cells. The use of recombinant lactoferrins mutated in the LPS-binding sites indicates that this inhibitory effect is mediated by an interaction of lactoferrin with LPS and CD14s that suppresses the endotoxin biological activity. Furthermore, since dimeric IL-8 and lactoferrin are both proteoglycan-binding molecules, the competition between these proteins for heparin binding was investigated. Lactoferrin strongly inhibited the interaction of radiolabeled IL-8 to immobilized heparin, whereas a lactoferrin variant lacking the amino acid residues essential for heparin binding was not inhibitory. Moreover, this process is specific, since serum transferrin, a glycoprotein whose structure is close to that of lactoferrin, did not prevent the interaction of IL-8 with heparin. These results suggest that the anti-inflammatory properties of lactoferrin during septicemia are related, at least in part, to the regulation of IL-8 production and also to the ability of lactoferrin to compete with chemokines for their binding to proteoglycans.     

Aortic function is compromised in a rat model of polycystic ovary syndrome

BACKGROUND: Arterial mechanical parameters are modified in women with polycystic ovary syndrome (PCOS), before and during pregnancy. This study tested the hypothesis that aortic mechanics and endothelial function are modified in the mifepristone-treated rat model of PCOS. METHODS: Female rats injected daily with mifepristone or vehicle for 7-9 days were assessed by ultrasound to allow estimation of aortic stiffness index and compliance. The influence of acetylcholine (ACh) and sodium nitroprusside (SNP) on dissected phenylephrine-contracted aortic rings was assessed. RESULTS: Aortic compliance was reduced by 67% in mifepristone-treated rats versus controls (P<0.05), while stiffness index was increased 2.3-fold (P<0.02). ACh-induced dilation was less in aortic rings from mifepristone-treated rats (P=0.022) and was less sensitive to the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) (P<0.001), while SNP-induced dilation was greater (P=0.001). CONCLUSIONS: Aortic mechanics in vivo and endothelial function in vitro were consistently perturbed in mifepristone-treated rats. Aortic ring behaviour suggested that NO release was depressed or degradation elevated, with a compensatory increase in NO sensitivity and/or activation of a non-NO-mediated relaxation mechanism. The mifepristone-treated rat is a valid model for investigation of the vascular deficits seen in PCOS.     

Myd88-dependent in vivo maturation of splenic dendritic cells induced by Leishmania donovani and other Leishmania species

The usual agent of visceral leishmaniasis in the Old World is Leishmania donovani, which typically produces systemic diseases in humans and mice. L. donovani has developed efficient strategies to infect and persist in macrophages from spleen and liver. Dendritic cells (DC) are sentinels of the immune system. Following recognition of evolutionary conserved microbial products, DC undergo a maturation process and activate antigen-specific na?ve T cells. In the present report we provide new insights into how DC detect Leishmania in vivo. We demonstrate that in both C57BL/6 and BALB/c mice, systemic injection of L. donovani induced the migration of splenic DC from marginal zones to T-cell areas. During migration, DC upregulated the expression of major histocompatibility complex II and costimulatory receptors (such as CD40, CD80, and CD86). Leishmania-induced maturation requires live parasites and is not restricted to L. donovani, as L. braziliensis, L. major, and L. mexicana induced a similar process. Using a green fluorescent protein-expressing parasite, we demonstrate that DC undergoing maturation in vivo display no parasite internalization. We also show that L. donovani-induced DC maturation was partially abolished in MyD88-deficient mice. Taken together, our data suggest that Leishmania-induced DC maturation results from direct recognition of Leishmania by DC, and not from DC infection, and that MyD88-dependent receptors are implicated in this process.     

Wake detection capacity of actigraphy during sleep

STUDY OBJECTIVES: To evaluate the ability of actigraphy compared to polysomnography (PSG) to detect wakefulness in subjects submitted to 3 sleep conditions with different amounts of wakefulness: a nocturnal sleep episode and 2 daytime recovery sleep episodes, one with placebo and one with caffeine. A second objective was to compare the ability of 4 different scoring algorithms (2 threshold algorithms and 2 regression analysis algorithms) to detect wake in the 3 sleep conditions. DESIGN: Three nights of simultaneous actigraphy (Actiwatch-L, Mini-Mitter/Respironics) and PSG recordings in a within-subject design. SETTING: Chronobiology laboratory. PARTICIPANTS: Fifteen healthy subjects aged between 20 and 60 years (7M, 8F). INTERVENTIONS: 200 mg of caffeine and daytime recovery sleep. RESULTS: An epoch-by-epoch comparison between actigraphy and PSG showed a significant decrease in actigraphy accuracy with increased wakefulness in sleep conditions due to the low sleep specificity of actigraphy (generally <50%). Actigraphy overestimated total sleep time and sleep efficiency more strongly in conditions involving more wakefulness. Compared to the 2 regression algorithms, the 2 threshold algorithms were less able to detect wake when the sleep episode involved more wakefulness, and they tended to alternate more between wake and sleep in the scoring of long periods of wakefulness resulting in an overestimation of the number of awakenings. CONCLUSION: The very low ability of actigraphy to detect wakefulness casts doubt on its validity to measure sleep quality in clinical populations with fragmented sleep or in situations where the sleep-wake cycle is challenged, such as jet lag and shift work.     

Social recognition memory requires protein synthesis after reactivation

Recent evidence indicates that reactivation of consolidated memories returns them to a protein-synthesis-dependent state called reconsolidation. The hypothesis that memories reconsolidate has never been assessed in social memory. The authors tested whether sheep (Ovis aries) mothers' memory of their lambs undergoes reconsolidation upon reactivation. After 7 days of mother-young contact, ewes were separated from their lambs for 8 hr, after which the lambs were reintroduced to their mothers for a 10-min reactivation session. Before reactivation, mothers received a subcutaneous injection of either the protein-synthesis inhibitor cycloheximide (CY, 1 mg/kg) or vehicle. Mothers' lamb memory was tested 1 hr (short-term memory [STM]) or 16 hr (long-term memory [LTM]) after reactivation. Mothers treated with CY exhibited intact STM but deficient LTM. CY injection without reactivation or before presentation of an alien lamb induced no deficit in LTM. CY-induced LTM deficit was alleviated by (a) introducing a reminder just before the LTM test, (b) extending mother-young contact, and (c) preventing suckling by the familiar lamb during reactivation. Thus, reconsolidation can be shown to exist in social memory, and some of its boundary conditions are discussed.