Virus Detection and Semiquantitation in Explanted Heart Tissues of Idiopathic Dilated Cardiomyopathy Adult Patients by Use of PCR Coupled with Mass Spectrometry Analysis

Viral detection in heart tissues has become a central issue for the diagnosis and exploration of the pathogenesis of idiopathic dilated cardiomyopathy (IDCM). In the present study, common cardiotropic viruses in 67 explanted heart samples of 31 IDCM adult patients were detected and semiquantified by using for the first time a new technology based on PCR assay coupled to electrospray ionization-time of flight mass spectrometry analysis (PCR-MS), with comparison to reference quantitative real-time PCR (RT-qPCR) assay. PCR-MS identified single or mixed enterovirus (EV) and parvovirus B19 (PVB19) infections in 27 (40.2%) of 67 samples, corresponding to 15 (48.3%) of the 31 patients, whereas RT-qPCR identified viral infections in 26 (38.8%) samples, corresponding to 16 (51.6%) of the patients. The PCR-MS results correlated well with EV and PVB19 detection by RT-qPCR (kappa = 0.85 [95% confidence interval {CI}, 0.72 to 1.00] and kappa = 0.82 [95% CI, 0.66 to 0.99], respectively). The levels of EV RNA (median, 550 [range, 178 to 3,200] copies/μg of total extracted nucleic acids) and of PVB19 DNA (median, 486 [range, 80 to 1,157] copies/μg of total extracted nucleic acids) were measured using PCR-MS and correlated with those obtained by RT-qPCR (r² = 0.57, P = 0.002 and r² = 0.64, P < 0.001 for EV and PVB19, respectively). No viruses other than EV and PVB19 strains were detected using the new PCR-MS technology, which is capable of simultaneously identifying 84 known human viruses in one assay. In conclusion, we identified single or mixed EV and PVB19 cardiac infections as potential causes of IDCM. The PCR-MS analysis appeared to be a valuable tool to rapidly detect and semiquantify common viruses in cardiac tissues and may be of major interest to better understand the role of viruses in unexplained cardiomyopathies.     

Consequences of exposure to peri-articular injections of micro- and nano-particulate cobalt–chromium alloy

Metal hip replacements generate both metal particles and ions. The biological effects of peri-articular exposure to nanometre and micron sized cobalt chrome (CoCr) wear particles were investigated in a mouse model. Mice received injections of two clinically relevant doses of nanoparticles (32 nm), one of micron sized (2.9 μm) CoCr particles or vehicle alone into the right knee joint at 0, 6, 12 and 18 weeks. Mice were analysed for genotoxic and immunological effects 1, 4 and 40 weeks post exposure. Nanoparticles but not micron particles progressively corroded at the injection site. Micron sized particles were physically removed. No increase of Co or Cr was seen in peripheral blood between 1 and 40 weeks post exposure to particles. No significant inflammatory changes were observed in the knee tissues including ALVAL or necrosis. DNA damage was increased in bone marrow at one and forty weeks and in cells isolated from frontal cortex at 40 weeks after injection with nanoparticles. Mice exposed to the micron sized, but not nanoparticles became immunologically sensitized to Cr(III), Cr (VI) and Ni(II) over the 40 week period as determined by lymphocyte transformation and ELISpot (IFN-γ and IL-2) assays. The data indicated that the response to the micron sized particles was Th1 driven, indicative of type IV hypersensitivity. This study adds to understanding of the potential adverse biological reactions to metal wear products.     

Transferrin-conjugated magnetic silica PLGA nanoparticles loaded with doxorubicin and paclitaxel for brain glioma treatment

The effective treatment of malignant brain glioma is hindered by the poor transport across the blood–brain barrier (BBB) and the low penetration across the blood-tumor barrier (BTB). In this study, transferrin-conjugated magnetic silica PLGA nanoparticles (MNP-MSN-PLGA-Tf NPs) were formulated to overcome these barriers. These NPs were loaded with doxorubicin (DOX) and paclitaxel (PTX), and their anti-proliferative effect was evaluated in vitro and in vivo. The in vitro cytotoxicity of drug-loaded NPs was evaluated in U-87 cells. The delivery and the subsequent cellular uptake of drug-loaded NPs could be enhanced by the presence of magnetic field and the usage of Tf as targeting ligand, respectively. In particular, cells treated with DOX-PTX-NPs-Tf with magnetic field showed the highest cytotoxicity as compared to those treated with DOX-PTX-NPs-Tf, DOX-PTX-NPs, DOX-PTX-NPs-Tf with free Tf. The in vivo therapeutic efficacy of drug-loaded NPs was evaluated in intracranial U-87 MG-luc2 xenograft of BALB/c nude mice. In particular, the DOX-PTX-NPs-Tf treatment exhibited the strongest anti-glioma activity as compared to the PTX-NPs-Tf, DOX-NPs-Tf or DOX-PTX-NPs treatment. Mice did not show acute toxicity after administrating with blank MNP-MSN-PLGA-Tf NPs. Overall, MNP-MSN-PLGA-Tf NPs are promising carriers for the delivery of dual drugs for effective treatment of brain glioma.     

Interspecies differences with in vitro and in vivo models of vascular tissue engineering

In arterial replacement there is a clear clinical need for a functional substitute possessing appropriate haemocompatible properties to be implanted as small diameter artery. Endothelial cell seeding constitutes an appreciated method to improve blood compatibility on the condition that cells firmly adhere to the support. Along this way, an innovative technique based on multilayered polyelectrolyte films (PEM) as cell adhesive substrate was previously validated in vitro and in vivo in a small-animal model. In this study, we extended the work on a larger animal (sheep) to validate furthermore the paradigm of PEM functionalization for vascular substitutes. We tested in vitro: the efficiency of PEM to induce endothelial progenitor differentiation in sheep endothelial cells; the ability of PEM to sustain cell proliferation and allow resistance to shear stress; the fate of PEM-coated de-endothelialized human saphenous veins under flow conditions, a prerequisite step before in vivo experiments. Despite in vitro differences we were encouraged by testing in vivo PEM-coated prosthesis as carotid replacement in sheep, but without success. In order to explain the implantation failure, an in vitro haemocompatibility evaluation was performed that highlighted interspecies differences able to explain, at least in part, the graft failure obtained.     

Chromatin-to-nucleoprotamine transition is controlled by the histone H2B variant TH2B

The conversion of male germ cell chromatin to a nucleoprotamine structure is fundamental to the life cycle, yet the underlying molecular details remain obscure. Here we show that an essential step is the genome-wide incorporation of TH2B, a histone H2B variant of hitherto unknown function. Using mouse models in which TH2B is depleted or C-terminally modified, we show that TH2B directs the final transformation of dissociating nucleosomes into protamine-packed structures. Depletion of TH2B induces compensatory mechanisms that permit histone removal by up-regulating H2B and programming nucleosome instability through targeted histone modifications, including lysine crotonylation and arginine methylation. Furthermore, after fertilization, TH2B reassembles onto the male genome during protamine-to-histone exchange. Thus, TH2B is a unique histone variant that plays a key role in the histone-to-protamine packing of the male genome and guides genome-wide chromatin transitions that both precede and follow transmission of the male genome to the egg.     

Staphylococcal and Streptococcal Superantigen Exotoxins

SUMMARY

This review begins with a discussion of the large family of Staphylococcus aureus and beta-hemolytic streptococcal pyrogenic toxin T lymphocyte superantigens from structural and immunobiological perspectives. With this as background, the review then discusses the major known and possible human disease associations with superantigens, including associations with toxic shock syndromes, atopic dermatitis, pneumonia, infective endocarditis, and autoimmune sequelae to streptococcal illnesses. Finally, the review addresses current and possible novel strategies to prevent superantigen production and passive and active immunization strategies.     

Simultaneous voxel‐wise analysis of brain and spinal cord morphometry and microstructure within the SPM framework

To validate a simultaneous analysis tool for the brain and cervical cord embedded in the statistical parametric mapping (SPM) framework, we compared trauma‐induced macro‐ and microstructural changes in spinal cord injury (SCI) patients to controls. The findings were compared with results obtained from existing processing tools that assess the brain and spinal cord separately. A probabilistic brain‐spinal cord template (BSC) was generated using a generative semi‐supervised modelling approach. The template was incorporated into the pre‐processing pipeline of voxel‐based morphometry and voxel‐based quantification analyses in SPM. This approach was validated on T1‐weighted scans and multiparameter maps, by assessing trauma‐induced changes in SCI patients relative to controls and comparing the findings with the outcome from existing analytical tools. Consistency of the MRI measures was assessed using intraclass correlation coefficients (ICC). The SPM approach using the BSC template revealed trauma‐induced changes across the sensorimotor system in the cord and brain in SCI patients. These changes were confirmed with established approaches covering brain or cord, separately. The ICC in the brain was high within regions of interest, such as the sensorimotor cortices, corticospinal tracts and thalamus. The simultaneous voxel‐wise analysis of brain and cervical spinal cord was performed in a unique SPM‐based framework incorporating pre‐processing and statistical analysis in the same environment. Validation based on a SCI cohort demonstrated that the new processing approach based on the brain and cord is comparable to available processing tools, while offering the advantage of performing the analysis simultaneously across the neuraxis.     

VEGF-A165b Is an Endogenous Neuroprotective Splice Isoform of Vascular Endothelial Growth Factor A in?Vivo and in?Vitro

Vascular endothelial growth factor (VEGF) A is generated as two isoform families by alternative RNA splicing, represented by VEGF-A₁₆₅a and VEGF-A₁₆₅b. These isoforms have opposing actions on vascular permeability, angiogenesis, and vasodilatation. The proangiogenic VEGF-A₁₆₅a isoform is neuroprotective in hippocampal, dorsal root ganglia, and retinal neurons, but its propermeability, vasodilatatory, and angiogenic properties limit its therapeutic usefulness. In contrast, a neuroprotective effect of endogenous VEGF-A₁₆₅b on neurons would be advantageous for neurodegenerative pathologies. Endogenous expression of human and rat VEGF-A₁₆₅b was detected in hippocampal and cortical neurons. VEGF-A₁₆₅b formed a significant proportion of total VEGF-A in rat brain. Recombinant human VEGF-A₁₆₅b exerted neuroprotective effects in response to multiple insults, including glutamatergic excitotoxicity in hippocampal neurons, chemotherapy-induced cytotoxicity of dorsal root ganglion neurons, and retinal ganglion cells (RGCs) in rat retinal ischemia-reperfusion injury in vivo. Neuroprotection was dependent on VEGFR2 and MEK1/2 activation but not on p38 or phosphatidylinositol 3–kinase activation. Recombinant human VEGF-A₁₆₅b is a neuroprotective agent that effectively protects both peripheral and central neurons in vivo and in vitro through VEGFR2, MEK1/2, and inhibition of caspase-3 induction. VEGF-A₁₆₅b may be therapeutically useful for pathologies that involve neuronal damage, including hippocampal neurodegeneration, glaucoma diabetic retinopathy, and peripheral neuropathy. The endogenous nature of VEGF-A₁₆₅b expression suggests that non–isoform-specific inhibition of VEGF-A (for antiangiogenic reasons) may be damaging to retinal and sensory neurons.Vascular endothelial growth factor (VEGF) A, originally described as a potent vascular permeability and growth factor for endothelial cells, is up-regulated in the brain during stroke and ischemic episodes¹ and has been linked with many neuronal diseases. The most widely studied isoform of VEGF-A, VEGF-A₁₆₅a, is up-regulated in hypoxia, induces increased vascular permeability in neuronal vasculature, and can stimulate angiogenesis after ischemic episodes. The resulting edema and hyperemia can be damaging, but VEGF-A₁₆₅a has also been found to have direct anticytotoxic effects on neurons, raising the possibility that it may act as an endogenous neuroprotective agent in neurodegenerative pathologies. VEGF-A exerts neurotrophic (survival) and neurotropic (neurogenesis and axon outgrowth) actions, which, although initially thought to be a function of increased angiogenesis and perfusion after neuronal injury,² are now appreciated as direct effects of VEGF-A on neurons.The vegfa gene encodes numerous products by differential splicing, but not all isoforms exert the same effects.³ Alternative splicing of exon 8 leads to two functionally distinct families: the proangiogenic VEGF-A_xxxa family and the counteracting VEGF-A_xxxb family.^4,5 VEGF-A₁₆₅b prevents the VEGF-A₁₆₅a effects on increased vascular permeability, blood vessel growth, and vasodilatation.^4–7The therapeutic potential of VEGF-A and anti–VEGF-A treatments are now widely recognized, and effective anti–VEGF-A treatments are available in ophthalmology⁸ and oncology.⁹ The finding that VEGF-A is implicated in neuronal disorders (eg, Alzheimer disease, Parkinson disease, Huntington disease, diabetic neuropathy, and amyotrophic lateral sclerosis¹⁰) provides a rationale for the use of VEGF-A as a therapeutic agent in neurodegenerative conditions. Although this rationale is supported by preclinical evidence,¹¹ the identification of the VEGF-A_xxxb family requires reexamination of VEGF-A isoforms in these contexts to allow for the clear evidence that VEGF-A splicing variants are not functionally equivalent³ and to determine whether augmentation of the proangiogenic isoform family (VEGF-A_xxxa) alone may have deleterious effects (eg, in occult malignancy and carcinoma in situ).The neuroprotective profile of the exon 8 alternatively spliced isoforms VEGF-A_xxxb remains unexplored. Interestingly, VEGF-A_xxxb isoforms do not exhibit the vascular effects seen with VEGF-A_xxxa isoforms, such as a sustained increase in capillary permeability or hypotension.^5,12 The lack of these potential adverse effects may make VEGF-A_xxxb isoforms more amenable as therapeutic agents in neurodegenerative diseases.We therefore tested the hypothesis that VEGF-A₁₆₅b is neuroprotective for central and peripheral neurons. We found that VEGF-A₁₆₅b is expressed in central neurons and is neuroprotective in vitro and in vivo. This finding indicates that VEGF-A₁₆₅b may prove to be a suitable therapeutic agent in neurodegenerative disorders, exhibiting fewer adverse effects than VEGF-A₁₆₅a.