Changes in the metabolism of sphingolipids after subarachnoid hemorrhage

We previously described how ceramide (Cer), a mediator of cell death, increases in the cerebrospinal fluid (CSF) of subarachnoid hemorrhage (SAH) patients. This study investigates the alterations of biochemical pathways involved in Cer homeostasis in SAH. Cer, dihydroceramide (DHC), sphingosine‐1‐phosphate (S1P), and the activities of acid sphingomyelinase (ASMase), neutral sphingomyelinase (NSMase), sphingomyelinase synthase (SMS), S1P‐lyase, and glucosylceramide synthase (GCS) were determined in the CSF of SAH subjects and in brain homogenate of SAH rats. Compared with controls (n = 8), SAH patients (n = 26) had higher ASMase activity (10.0 ± 3.5 IF/µl· min vs. 15.0 ± 4.6 IF/µl ? min; P = 0.009) and elevated levels of Cer (11.4 ± 8.8 pmol/ml vs. 33.3 ± 48.3 pmol/ml; P = 0.001) and DHC (1.3 ± 1.1 pmol/ml vs. 3.8 ± 3.4 pmol/ml; P = 0.001) in the CSF. The activities of GCS, NSMase, and SMS in the CSF were undetectable. Brain homogenates from SAH animals had increased ASMase activity (control: 9.7 ± 1.2 IF/µg ? min; SAH: 16.8 ± 1.6 IF/µg ? min; P < 0.05) and Cer levels (control: 3,422 ± 26 fmol/nmol of total lipid P; SAH: 7,073 ± 2,467 fmol/nmol of total lipid P; P < 0.05) compared with controls. In addition, SAH was associated with a reduction of 60% in S1P levels, a 40% increase in S1P‐lyase activity, and a twofold increase in the activity of GCS. In comparison, NSMase and SMS activities were similar to controls and SMS activities similar to controls. In conclusion, our results show an activation of ASMase, S1P‐lyase, and GCS resulting in a shift in the production of protective (S1P) in favor of deleterious (Cer) sphingolipids after SAH. Additional studies are needed to determine the effect of modulators of the pathways described here in SAH. © 2015 Wiley Periodicals, Inc.     

Coxiella burnetii Effector Proteins That Localize to the Parasitophorous Vacuole Membrane Promote Intracellular Replication

The intracellular bacterial pathogen Coxiella burnetii directs biogenesis of a parasitophorous vacuole (PV) that acquires host endolysosomal components. Formation of a PV that supports C. burnetii replication requires a Dot/Icm type 4B secretion system (T4BSS) that delivers bacterial effector proteins into the host cell cytosol. Thus, a subset of T4BSS effectors are presumed to direct PV biogenesis. Recently, the PV-localized effector protein CvpA was found to promote C. burnetii intracellular growth and PV expansion. We predict additional C. burnetii effectors localize to the PV membrane and regulate eukaryotic vesicle trafficking events that promote pathogen growth. To identify these vacuolar effector proteins, a list of predicted C. burnetii T4BSS substrates was compiled using bioinformatic criteria, such as the presence of eukaryote-like coiled-coil domains. Adenylate cyclase translocation assays revealed 13 proteins were secreted in a Dot/Icm-dependent fashion by C. burnetii during infection of human THP-1 macrophages. Four of the Dot/Icm substrates, termed Coxiella vacuolar protein B (CvpB), CvpC, CvpD, and CvpE, labeled the PV membrane and LAMP1-positive vesicles when ectopically expressed as fluorescently tagged fusion proteins. C. burnetii ΔcvpB, ΔcvpC, ΔcvpD, and ΔcvpE mutants exhibited significant defects in intracellular replication and PV formation. Genetic complementation of the ΔcvpD and ΔcvpE mutants rescued intracellular growth and PV generation, whereas the growth of C. burnetii ΔcvpB and ΔcvpC was rescued upon cohabitation with wild-type bacteria in a common PV. Collectively, these data indicate C. burnetii encodes multiple effector proteins that target the PV membrane and benefit pathogen replication in human macrophages.     

A broadly neutralizing human monoclonal antibody is effective against H7N9

Emerging strains of influenza represent a significant public health threat with potential pandemic consequences. Of particular concern are the recently emerged H7N9 strains which cause pneumonia with acute respiratory distress syndrome. Estimates are that nearly 80% of hospitalized patients with H7N9 have received intensive care unit support. VIS410, a human antibody, targets a unique conserved epitope on influenza A. We evaluated the efficacy of VIS410 for neutralization of group 2 influenza strains, including H3N2 and H7N9 strains in vitro and in vivo. VIS410, administered at 50 mg/kg, protected DBA mice infected with A/Anhui/2013 (H7N9), resulting in significant survival benefit upon single-dose (−24 h) or double-dose (−12 h, +48 h) administration (P < 0.001). A single dose of VIS410 at 50 mg/kg (−12 h) combined with oseltamivir at 50 mg/kg (−12 h, twice daily for 7 d) in C57BL/6 mice infected with A/Shanghai 2/2013 (H7N9) resulted in significant decreased lung viral load (P = 0.002) and decreased lung cytokine responses for nine of the 11 cytokines measured. Based on these results, we find that VIS410 may be effective either as monotherapy or combined with antivirals in treating H7N9 disease, as well as disease from other influenza strains.Influenza, a zoonotic viral disease, is responsible for substantial human morbidity and mortality yearly, with periodic elevations due to emergence of novel viral strains, either through mutation or genetic reassortment in a variety of animal reservoirs, including pigs, birds, and seals. Antigenic naivety within the population, coupled with the advent of a virus strain that can effectively transmit via respiratory droplets, can lead to epidemic or pandemic outbreaks. In addition, viruses with increased virulence, such as H5N1 and H7N9, are associated with enhanced morbidity and case fatality, estimated at 30–60% despite the availability of current antiviral therapy.Patients hospitalized with H7N9 infection typically manifest a high fever and cough, hypoxemia, and opacities and/or consolidations on chest radiology, with associated findings including shock, acute kidney injury, and the development of acute respiratory distress syndrome (ARDS). The high mortality associated with H7N9 infection and development of ARDS is similar to what has been reported for H5N1. An associated cytokine storm has been described in both of these patient groups, with proinflammatory cytokines/chemokines documented in plasma and pulmonary lavage samples (1–3). The increased cytokine responses have recently been correlated with increased severity and mortality observed in patients (2–4). Elevated levels of interleukin (IL)-10, IL-6, IL-8, and macrophage inflammatory protein-1β (MIP-1β) in plasma were found to be predictive of a less favorable or fatal outcome. Furthermore, IL-1β, interferon (IFN)-γ, MIP-1α, and MIP-1β were all significantly elevated in the bronchial lavage samples at a 100- to 1,000-fold increase compared with plasma concentrations, and tumor necrosis factor (TNF)-α was only detected in the lavage samples. Mouse models for H5N1 and H7N9 infection mimic this cytokine response and the lung pathology of ARDS (2). We therefore sought to examine the role of a broadly neutralizing antibody, VIS410, in mitigating this “cytokine storm” in infected mice and lowering lung viral concentrations in this sublethal H7N9 model. Since this agent would likely be used in combination with a neuraminidase inhibitor, we investigated the effect of VIS410 compared to, and in combination with, oseltamivir.Additionally, the DBA mouse has been found to have much higher susceptibility to influenza infection than either C56BL/6 or BALB/c mice (5, 6). A variety of influenza viruses, including H5N1 and influenza B viruses, have been shown to be lethal to DBA mice without prior adaptation (7, 8). We reasoned that to complement the cytokine measurements in BALB/c mice, a lethal DBA mouse model could be used to examine the effect of VIS410 on mortality, thereby providing an appropriate model of the significant morbidity and mortality associated with H7N9 infection in humans. We therefore additionally evaluated VIS410 in a lethal model of H7N9 disease.     

Development and aging of cortical thickness correspond to genetic organization patterns

There is a growing realization that early life influences have lasting impact on brain function and structure. Recent research has demonstrated that genetic relationships in adults can be used to parcellate the cortex into regions of maximal shared genetic influence, and a major hypothesis is that genetically programmed neurodevelopmental events cause a lasting impact on the organization of the cerebral cortex observable decades later. Here we tested how developmental and lifespan changes in cortical thickness fit the underlying genetic organizational principles of cortical thickness in a longitudinal sample of 974 participants between 4.1 and 88.5 y of age with a total of 1,633 scans, including 773 scans from children below 12 y. Genetic clustering of cortical thickness was based on an independent dataset of 406 adult twins. Developmental and adult age-related changes in cortical thickness followed closely the genetic organization of the cerebral cortex, with change rates varying as a function of genetic similarity between regions. Cortical regions with overlapping genetic architecture showed correlated developmental and adult age change trajectories and vice versa for regions with low genetic overlap. Thus, effects of genes on regional variations in cortical thickness in middle age can be traced to regional differences in neurodevelopmental change rates and extrapolated to further adult aging-related cortical thinning. This finding suggests that genetic factors contribute to cortical changes through life and calls for a lifespan perspective in research aimed at identifying the genetic and environmental determinants of cortical development and aging.There is a growing realization that events during development impact brain and cognition throughout the entire lifespan (1). For instance, the major portion of the relationship between cortical thickness and IQ in old age can be explained by childhood IQ (2), and genotype may explain a substantial part of the lifetime stability in intelligence (3). Effects of genes on the organization of the cortex have been shown in adults (4–6), but it is unknown whether and how regional differences in cortical development correspond to these regional genetic subdivisions.Although consensus has not been reached for the exact trajectories, cortical thickness as measured by MRI appears to decrease in childhood (7–12). The exact foundation for this thinning is not known, as MRI provides merely representations of the underlying neurobiology, and available histological data cannot with certainty be used to guide interpretations of MRI results. Although speculative, apparent thickness decrease may be grounded in factors such as synaptic pruning and intracortical myelination, although the link between established synaptic processes (13–15) and cortical thickness has not been empirically confirmed. After childhood, cortical thinning continues throughout the remainder of the lifespan, speculated to reflect neuronal shrinkage and reductions in number of spines and synapses (16), although similar to development, we lack data to support a direct connection between cortical thinning and specific neurobiological events.It has been demonstrated that genetic correlations between thickness in different surface locations can be used to parcellate the adult cortex into regions of maximal shared genetic influence (4). This result can be interpreted according to the hypothesis that genetically programmed neurodevelopmental events cause lasting impact on the organization of the cerebral cortex detectable decades later (4–6). Here we tested how developmental and lifespan changes fit the genetic organization of cortical thickness in a large longitudinal sample with 1,633 scans from 974 participants between 4.1 and 88.5 y of age, including 773 scans from children below 12 y Genetically based subdivisions of cortical thickness from an independent dataset of 406 twins (4) were applied to the data, yielding 12 separate regions under maximum control of shared genetic influences. We hypothesized that thickness in cortical regions with overlapping genetic architecture would show similar developmental and adult age change trajectories and dissimilar trajectories for regions with low genetic overlap.     

Endovascular coil embolization of a spinal epidural arteriovenous fistula with associated cord compression from an enlarging venous varix

Spinal arteriovenous fistulas (AVFs) completely isolated to the epidural compartment are exceedingly rare. As such, the optimal management of these lesions is poorly defined. The aim of this technical note is to describe our endovascular technique for the occlusion of a purely epidural AVF of the thoracic spine associated with cord compression from an associated enlarging venous varix. A 40-year-old male presented with severe right-sided back pain and anterior thigh numbness after a sports-related back injury six months previously. Spinal magnetic resonance imaging (MRI) showed an enhancing, extradural mass lesion at T12. Spinal angiography revealed an epidural AVF supplied by a radicular branch of the right T12 subcostal artery and draining into the paravertebral lumbar veins, as well as an adjacent 20 × 13 mm² contrast-filling sac, compatible with a dilated venous varix. There was no evidence of intradural venous drainage. We elected to proceed with endovascular treatment of the lesion. At the time of embolization five days later, the venous varix had enlarged to 26 × 16 mm². The T12 epidural AVF was completely occluded with two coils, without residual or recurrent AVF on follow-up angiography one month later. The patient made a full recovery, and complete resolution of the venous varix and cord compression were noted on MRI at three months follow-up. Endovascular coil embolization can be successfully employed for the treatment of appropriately selected spinal epidural AVFs. Cord compression from an enlarging venous varix can be treated concurrently with endovascular occlusion of an associated spinal epidural AVF.     

Comparison of current guidelines for primary prevention of coronary heart disease

OBJECTIVE: In primary prevention of atherosclerotic disease, it is difficult to decide when medical treatment should be initiated. The main goal of the study was to compare different guidelines for coronary heart disease (CHD) risk assessment and initiation of lipid-lowering therapy. DESIGN: Cross-sectional evaluation. SETTING: An outpatient lipid and diabetes clinic in a university hospital. PARTICIPANTS/METHODS: Risk factor data obtained on 100 consecutive patients (58 men and 42 women) without clinical evidence of cardiovascular disease were used to compare the Framingham risk equation, the U.S. National Cholesterol Education Program (Adult Treatment Panel III) (NCEP ATP III) guidelines, the joint European Societies guidelines, the joint British guidelines, the revised Sheffield table, and the Munster Heart Study calculator (PROCAM) CHD risk assessment and lipid-lowering therapy. RESULTS: Guidelines could be applied to different subsets of the cohort, ranging from 22% (PROCAM) to 95% of the cohort (revised Sheffield table). All guidelines (except PROCAM) could be applied to a total of 62 patients. Guidelines predicted > or =20% risk for developing CHD over 10 years in 53% (NCEP ATP III), 26% (European) and 32% (British), while Framingham predicted this risk level in 34%. CHD risk was estimated to be > or =3%/year in 5% according to Sheffield, while Framingham predicted this risk in 13%. Lipid-lowering drug therapy is recommended in 52% by NCEP ATP III, while European, British, and Sheffield guidelines recommend this in 26%, 35%, and 5%, respectively. CONCLUSIONS: Guidelines for assessing CHD risk and lipid-lowering therapy differ greatly. Therefore, these algorithms must be used with caution.     

A two-year prospective controlled study of bone mass and bone turnover in children with early juvenile idiopathic arthritis

OBJECTIVE: To explore early changes and predictors of bone mass in children with juvenile idiopathic arthritis (JIA) in order to identify patients who will develop bone mass reductions. METHODS: We conducted a prospective cohort study of 108 children with early JIA (ages 6-18 years; mean disease duration 19.3 months) who were individually matched with 108 healthy children for age, sex, race, and county of residence. Bone mass and changes in total body, spine, femur, and forearm bone mineral density and bone mineral content (BMC), body composition, growth, and biochemical parameters of bone turnover were examined at baseline and at followup a mean of 24 months later. Low bone mass was defined as a Z score >1 SD below the reference population. RESULTS: Of the 200 children evaluated at followup, the 100 healthy children had greater gains in total body BMC (P = 0.035), distal radius BMC (P < 0.001), and total body lean mass (P < 0.001) than did the 100 JIA patients. Low or very low total body BMC was observed in 24% of the patients and 12% of the healthy children. Bone formation, bone resorption, and weight-bearing activities were reduced in the patients compared with the healthy children. Multiple regression analysis showed that in patients with JIA, serum bone-specific alkaline phosphatase, serum C-telopeptide of type I collagen, and weight-bearing activities were independent predictors of changes in total body BMC. Total body BMC was lower in patients with polyarticular onset than in those with oligoarticular disease onset. CONCLUSION: Patients with JIA have moderate reductions in bone mass gains, bone turnover, and total body lean mass early in the disease course.