Bimagrumab vs Optimized Standard of Care for Treatment of Sarcopenia in Community-Dwelling Older Adults: A Randomized Clinical Trial.

Importance: The potential benefit of novel skeletal muscle anabolic agents to improve physical function in people with sarcopenia and other muscle wasting diseases is unknown. Objective: To confirm the safety and efficacy of bimagrumab plus the new standard of care on skeletal muscle mass, strength, and physical function compared with standard of care alone in community-dwelling older adults with sarcopenia. Design, Setting, and Participants: This double-blind, placebo-controlled, randomized clinical trial was conducted at 38 sites in 13 countries among community-dwelling men and women aged 70 years and older meeting gait speed and skeletal muscle criteria for sarcopenia. The study was conducted from December 2014 to June 2018, and analyses were conducted from August to November 2018. Interventions: Bimagrumab 700 mg or placebo monthly for 6 months with adequate diet and home-based exercise. Main Outcomes and Measures: The primary outcome was the change in Short Physical Performance Battery (SPPB) score after 24 weeks of treatment. Secondary outcomes included 6-minute walk distance, usual gait speed, handgrip strength, lean body mass, fat body mass, and standard safety parameters. Results: A total of 180 participants were recruited, with 113 randomized to bimagrumab and 67 randomized to placebo. Among these, 159 participants (88.3%; mean [SD] age, 79.1 [5.3] years; 109 [60.6%] women) completed the study. The mean SPPB score increased by a mean of 1.34 (95% CI, 0.90 to 1.77) with bimagrumab vs 1.03 (95% CI, 0.53 to 1.52) with placebo (P = .13); 6-minute walk distance increased by a mean of 24.60 (95% CI, 7.65 to 41.56) m with bimagrumab vs 14.30 (95% CI, -4.64 to 33.23) m with placebo (P = .16); and gait speed increased by a mean of 0.14 (95% CI, 0.09 to 0.18) m/s with bimagrumab vs 0.11 (95% CI, 0.05 to 0.16) m/s with placebo (P = .16). Bimagrumab was safe and well-tolerated and increased lean body mass by 7% (95% CI, 6% to 8%) vs 1% (95% CI, 0% to 2%) with placebo, resulting in difference of 6% (95% CI, 4% to 7%) (P < .001). Conclusions and Relevance: This randomized clinical trial found no significant difference between participants treated with bimagrumab vs placebo among older adults with sarcopenia who had 6 months of adequate nutrition and light exercise, with physical function improving in both groups. Bimagrumab treatment was safe, well-tolerated, increased lean body mass, and decreased fat body mass. The effects of sarcopenia, an increasing cause of disability in older adults, can be reduced with proper diet and exercise. Trial Registration: ClinicalTrials.gov Identifier: NCT02333331; EudraCT number: 2014-003482-25.

Crystal structure of Yersinia pestis virulence factor YfeA reveals two polyspecific metal-binding sites.

Gram-negative bacteria use siderophores, outer membrane receptors, inner membrane transporters and substrate-binding proteins (SBPs) to transport transition metals through the periplasm. The SBPs share a similar protein fold that has undergone significant structural evolution to communicate with a variety of differentially regulated transporters in the cell. In Yersinia pestis, the causative agent of plague, YfeA (YPO2439, y1897), an SBP, is important for full virulence during mammalian infection. To better understand the role of YfeA in infection, crystal structures were determined under several environmental conditions with respect to transition-metal levels. Energy-dispersive X-ray spectroscopy and anomalous X-ray scattering data show that YfeA is polyspecific and can alter its substrate specificity. In minimal-media experiments, YfeA crystals grown after iron supplementation showed a threefold increase in iron fluorescence emission over the iron fluorescence emission from YfeA crystals grown from nutrient-rich conditions, and YfeA crystals grown after manganese supplementation during overexpression showed a fivefold increase in manganese fluorescence emission over the manganese fluorescence emission from YfeA crystals grown from nutrient-rich conditions. In all experiments, the YfeA crystals produced the strongest fluorescence emission from zinc and could not be manipulated otherwise. Additionally, this report documents the discovery of a novel surface metal-binding site that prefers to chelate zinc but can also bind manganese. Flexibility across YfeA crystal forms in three loops and a helix near the buried metal-binding site suggest that a structural rearrangement is required for metal loading and unloading.

Effects of Therapeutic and Supratherapeutic Doses of Siponimod (BAF312) on Cardiac Repolarization in Healthy Subjects.

PURPOSE: The International Conference on Harmonisation E14 guideline mandates an intensive cardiac safety evaluation in a clinical thorough QT study, typically in healthy subjects, for all new non-antiarrhythmic drugs with systemic bioavailability. This thorough QT study investigated the effects of therapeutic (2 mg) and supratherapeutic (10 mg) doses of siponimod (BAF312) on cardiac repolarization in healthy subjects. METHODS: The study was a randomized, double-blind, parallel-group, placebo- and moxifloxacin-controlled, multiple oral dose study. Eligible subjects were randomly assigned to 3 groups to receive siponimod (up-titration to 2 and 10 mg over 18 days), placebo (Days -1 to 18), or moxifloxacin 400 mg Days 10 and 18). Triplicate ECGs were extracted at prespecified time points from Holter ECGs recorded from 1 hour predose until 24 hours postdose at baseline and on-treatment assessment Days 10 and 18. The primary pharmacodynamic variable was the time-matched, placebo-corrected, baseline-adjusted mean QTcF (ΔΔQTcF) at steady-state conditions. In addition, the pharmacokinetic parameters of siponimod and its main circulating metabolite M3 and its metabolite M5 were evaluated. FINDINGS: Of the 304 enrolled subjects, 281 (92.4%) were included in the pharmacodynamic analysis and 270 (88.8%) completed the study. The upper bounds of the 2-sided 90% confidence intervals (CIs) for ΔΔQTcF at both siponimod doses were within the regulatory threshold of 10 milliseconds (ms) at all predefined on-treatment time points, with the absence of any dose-related effects. The highest observed upper limits of the 2-sided 90% CIs of 9.8 and 9.6 ms for therapeutic and supratherapeutic doses, respectively, were both observed at 3 hours postdose. No treatment-emergent QTc values >480 ms and no QTc increases of >60 ms from baseline were observed. Similar results were obtained with individualized heart rate correction of cardiac repolarization (QTcI). Assay validity was demonstrated by maximum ΔΔQTcF of >5 ms after 400 mg moxifloxacin on both on-treatment assessment days. The selected supratherapeutic dose produced approximately 5-fold higher exposures (Cmax and AUC) than the therapeutic dose, and was considered appropriate to investigate the effects of siponimod on QT/QTc at substantial multiples of the anticipated maximum therapeutic exposure. IMPLICATIONS: The findings provide evidence that siponimod is not associated with a significant arrhythmogenic potential related to QT prolongation.

Manganese transporters Yfe and MntH are Fur-regulated and important for the virulence of Yersinia pestis.

Yersinia pestis has a flea-mammal-flea transmission cycle, and is a zoonotic pathogen that causes the systemic diseases bubonic and septicaemic plague in rodents and humans, as well as pneumonic plague in humans and non-human primates. Bubonic and pneumonic plague are quite different diseases that result from different routes of infection. Manganese (Mn) acquisition is critical for the growth and pathogenesis of a number of bacteria. The Yfe/Sit and/or MntH systems are the two prominent Mn transporters in Gram-negative bacteria. Previously we showed that the Y. pestis Yfe system transports Fe and Mn. Here we demonstrate that a mutation in yfe or mntH did not significantly affect in vitro aerobic growth under Mn-deficient conditions. A yfe mntH double mutant did exhibit a moderate growth defect which was alleviated by supplementation with Mn. No short-term energy-dependent uptake of (54)Mn was observed in this double mutant. Like the yfeA promoter, the mntH promoter was repressed by both Mn and Fe via Fur. Sequences upstream of the Fur binding sequence in the yfeA promoter converted an iron-repressible promoter to one that is also repressed by Mn and Fe. To our knowledge, this is the first report identifying cis promoter elements needed to alter cation specificities involved in transcriptional repression. Finally, the Y. pestis yfe mntH double mutant had an ~133-fold loss of virulence in a mouse model of bubonic plague but no virulence loss in the pneumonic plague model. This suggests that Mn availability, bacterial Mn requirements or Mn transporters used by Y. pestis are different in the lungs (pneumonic plague) compared with systemic disease.

Sahel, savana, riverine and urban malaria in West Africa: Similar control policies with different outcomes.

The study sites for the West African ICEMR are in three countries (The Gambia, Senegal, Mali) and are located within 750 km of each other. In addition, the National Malaria Control Programmes of these countries have virtually identical policies: (1) Artemisinin Combination Therapies (ACTs) for the treatment of symptomatic Plasmodium falciparum infection, (2) Long-Lasting Insecticide-treated bed Nets (LLINs) to reduce the Entomololgic Inoculation Rate (EIR), and (3) sulfadoxine-pyrimethamine for the Intermittent Preventive Treatment of malaria during pregnancy (IPTp). However, the prevalence of P. falciparum malaria and the status of malaria control vary markedly across the four sites with differences in the duration of the transmission season (from 4-5 to 10-11 months), the intensity of transmission (with EIRs from unmeasurably low to 4-5 per person per month), multiplicity of infection (from a mean of 1.0 to means of 2-5) and the status of malaria control (from areas which have virtually no control to areas that are at the threshold of malaria elimination). The most important priority is the need to obtain comparable data on the population-based prevalence, incidence and transmission of malaria before new candidate interventions or combinations of interventions are introduced for malaria control.

Znu is the predominant zinc importer in Yersinia pestis during in vitro growth but is not essential for virulence.

Little is known about Zn homeostasis in Yersinia pestis, the plague bacillus. The Znu ABC transporter is essential for zinc (Zn) uptake and virulence in a number of bacterial pathogens. Bioinformatics analysis identified ZnuABC as the only apparent high-affinity Zn uptake system in Y. pestis. Mutation of znuACB caused a growth defect in Chelex-100-treated PMH2 growth medium, which was alleviated by supplementation with submicromolar concentrations of Zn. Use of transcriptional reporters confirmed that Zur mediated Zn-dependent repression and that it can repress gene expression in response to Zn even in the absence of Znu. Virulence testing in mouse models of bubonic and pneumonic plague found only a modest increase in survival in low-dose infections by the znuACB mutant. Previous studies of cluster 9 (C9) transporters suggested that Yfe, a well-characterized C9 importer for manganese (Mn) and iron in Y. pestis, might function as a second, high-affinity Zn uptake system. Isothermal titration calorimetry revealed that YfeA, the solute-binding protein component of Yfe, binds Mn and Zn with comparably high affinities (dissociation constants of 17.8 ± 4.4 nM and 6.6 ± 1.2 nM, respectively), although the complete Yfe transporter could not compensate for the loss of Znu in in vitro growth studies. Unexpectedly, overexpression of Yfe interfered with the znu mutant's ability to grow in low concentrations of Zn, while excess Zn interfered with the ability of Yfe to import iron at low concentrations; these results suggest that YfeA can bind Zn in the bacterial cell but that Yfe is incompetent for transport of the metal. In addition to Yfe, we have now eliminated MntH, FetMP, Efe, Feo, a substrate-binding protein, and a putative nickel transporter as the unidentified, secondary Zn transporter in Y. pestis. Unlike other bacterial pathogens, Y. pestis does not require Znu for high-level infectivity and virulence; instead, it appears to possess a novel class of transporter, which can satisfy the bacterium's Zn requirements under in vivo metal-limiting conditions. Our studies also underscore the need for bacterial cells to balance binding and transporter specificities within the periplasm in order to maintain transition metal homeostasis.

Thalamic D2 receptors in dementia with Lewy bodies, Parkinson's disease, and Parkinson's disease dementia.

Dementia with Lewy bodies (DLB) is characterized by progressive dementia with two of three core symptoms; Parkinsonism, visual hallucinations or disturbances of consciousness/fluctuating attention. Dementia in Parkinson's disease (PDD) has similar neuropsychiatric characteristics. Reduced nigrothalamic dopamine and altered thalamic D2 receptors may mediate some of the non-motor symptoms of DLB and PDD. The study aims were to ascertain whether thalamic D2 density was altered in Parkinson's disease (PD), PDD and DLB, and whether D2 density was related to core symptoms. Thalamic D2 receptor binding was measured by post-mortem autoradiography in 18 cases of DLB, 13 PDD, 6 PD and 14 normal elderly controls. Highest D2 density in control cases was in the intralaminar, midline, anterior and mediodorsal nuclei. In PD without dementia D2 binding was elevated above controls in all thalamic regions, significantly in reticular, laterodorsal, centromedian, ventral centromedian, parafascicular, paraventricular, ventroposterior, ventrolateral posterior, and ventrointermedius nuclei. Compared to controls, DLB cases with Parkinsonism (DLB+EPS) had significantly elevated D2 receptor density in laterodorsal and ventrointermedius nuclei; PDD cases had significantly raised density in the ventrointermedius, and DLB cases without Parkinsonism (DLB-EPS) did not show increased D2 density in any areas. In DLB and PDD cases with disturbances of consciousness, cases treated with neuroleptics had higher D2 binding in all thalamic regions, significantly in the mediodorsal and ventrolateral posterior nuclei. D2 receptor binding did not vary with cognitive decline (MMSE) or visual hallucinations, but was significantly higher with increased extrapyramidal symptoms.

Lewy body disease: thalamic cholinergic activity related to dementia and parkinsonism.

Within the spectrum of Lewy body disease cognitive impairment occurs in PD with dementia (PDD) and dementia with Lewy bodies (DLB). Although neocortical cholinergic deficits are associated with cognitive impairments in PDD and DLB, no neurochemical study has been published describing the thalamic cholinergic activity whereas the thalamus plays a major role in modulating cortical activity. Choline acetyltransferase (ChAT) activity was analyzed in reticular (Re), mediodorsal (MD) and centromedian (CM) thalamic nuclei in series of nine controls, five DLB with parkinsonism (DLB + P), five DLB without parkinsonism (DLB - P), six PD without dementia and 14 PDD cases. Significant reductions in ChAT were apparent in PDD as follows: in Re and MD nuclei compared with controls; in MD and CM nuclei compared with DLB + P; and in MD compared with PD. Increased ChAT activity was found in CM nuclei in DLB + P compared with DLB - P. These findings show that significant thalamic presynaptic cholinergic deficits occur only in cases of combined cortical and subcortical neurodegeneration in which dementia developed after prolonged parkinsonism.

Thalamic nicotinic receptors implicated in disturbed consciousness in dementia with Lewy bodies.

Disturbances of consciousness (DOC) are common in dementia with Lewy bodies (DLB). Following previous findings of preserved temporal cortical high-affinity nicotinic binding relating to DOC, we investigated this receptor in thalamus, an area of high nicotinic receptor concentration, implicated in consciousness. 5-[125I]-A-85380 binding, primarily reflecting the alpha4beta2 subtype, was compared in 16 DLB patients with DOC and 6 without DOC, matched for duration and severity of dementia. Binding was higher in patients with DOC compared to patients without DOC in all thalamic nuclei examined, reaching significance in the reticular and ventral anterior thalamic nuclei. Comparing DLB patients with and without DOC to previously reported controls revealed similar binding levels in patients with DOC and lower binding in patients without DOC, reaching significance in the ventral anterior, indicating preserved nicotinic receptor density in DLB patients with DOC. These findings, together with previous neocortical data, implicate nicotinic modulation of thalamo-cortical circuitry as a key component in the control of conscious awareness in DLB.

Effect of periodic vitamin A supplementation on mortality and morbidity of human immunodeficiency virus-infected children in Uganda: A controlled clinical trial.

OBJECTIVE: We investigated whether vitamin A supplementation would decrease mortality and morbidity rates in children infected with the human immunodeficiency virus (HIV). METHODS: We conducted a randomized, double-blind, placebo-controlled clinical trial at Mulago Hospital, a large hospital that serves the urban and semiurban populations of Kampala, Uganda. One hundred eighty-one HIV-infected children were enrolled at 6 mo and randomized to receive vitamin A supplementation, 60 mg retinol equivalent, or placebo every 3 mo from ages 15 to 36 mo. Morbidity was assessed through a 7-d morbidity history every 3 mo, and vital events were measured. Children received daily trimethoprim-sulfamethoxazole prophylactic therapy. RESULTS: After age 15 mo, children were followed for a median of 17.8 mo (interquartile range = 11.1 to 21.0 mo). The trial was stopped when there was a new policy to implement a program of mass supplementation of vitamin A in the country. Mortality rates among 87 children in the vitamin A group and 94 children in the control group were 20.6% and 32.9%, respectively, yielding a relative risk of 0.54 (95% confidence interval, 0.30 to 0.98; P = 0.044) after adjusting for baseline weight-for-height Z score. Children who received vitamin A had lower modified point prevalences of persistent cough (odds ratio, 0.47; 95% confidence interval, 0.23 to 0.96; P = 0.038) and chronic diarrhea (odds ratio, 0.48; 95% confidence interval, 0.19 to 1.18; P = 0.11) and a shorter duration of ear discharge (P = 0.03). Vitamin A supplementation had no significant effect on modified point prevalences of fever, ear discharge, bloody stools, or hospitalizations. CONCLUSIONS: Vitamin A supplementation decreases mortality rate in HIV-infected children and should be considered in the care for these children in developing countries.

Involvement of alpha6/alpha3 neuronal nicotinic acetylcholine receptors in neuropsychiatric features of Dementia with Lewy bodies: [(125)I]-alpha-conotoxin MII binding in the thalamus and striatum.

Dementia with Lewy bodies (DLB) is a neurodegenerative disease associated with a range of neuropsychiatric symptoms and reduced expression of neuronal nicotinic acetylcholine receptors (nAChRs) in neocortex, hippocampus, thalamus and basal ganglia. To determine whether there are selective associations between alterations in alpha6/alpha3 neuronal nicotinic acetylcholine receptors (nAChRs) and the two key neuropsychiatric features of DLB, impaired consciousness (IC) and visual hallucinations (VH), quantitative [(125)I]-alpha-conotoxin MII ([(125)I]-alpha-Ctx MII) autoradiography was undertaken on 28 people with DLB and 15 control cases from the Newcastle Brain Bank. There was a highly significant overall trend for reduced thalamic [(125)I]-alpha-Ctx MII binding in DLB (p < 0.001), with significant deficits in the centromedian, ventral lateral and ventroposterior medial thalamic nuclei (p < 0.05), together with caudate and putamen (p < 0.001). [(125)I]-alpha-Ctx MII binding was significantly lower in DLB cases with IC than without IC in the putamen (p < 0.05), however there was no significant association between [(125)I]-alpha-Ctx MII binding and VH. Reductions in [(125)I]-alpha-Ctx MII binding in caudate and putamen were paralleled by similar reductions in [(125)I]PE2I binding. [(125)I]PE2I binding was also significantly lower in DLB cases with IC than without IC in the caudate (p < 0.05) and putamen (p < 0.001). These results demonstrate that deficits in alpha6/alpha3 nAChRs occur in specific brain regions in DLB, may in part be related to the loss of dopaminergic neurons and may contribute to the development of impaired consciousness in the disorder.