119 research outputs found
Klebsiella pneumoniae-OMVs activate death-signaling pathways in Human Bronchial Epithelial Host Cells (BEAS-2B)
: The programmed cell death pathways of apoptosis are important in mammalian cellular protection from infections. The activation of these pathways depends on the presence of membrane receptors that bind bacterial components to activate the transduction mechanism. In addition to bacteria, these mechanisms can be activated by outer membrane vesicles (OMVs). OMVs are spherical vesicles of 20-250 nm diameter, constitutively released by Gram-negative bacteria. They contain several bacterial determinants including proteins, DNA/RNA and proteins, that activate different cellular processes in host cells. This study focused on Klebsiella pneumoniae-OMVs in activating death mechanisms in human bronchial epithelial cells (BEAS-2B). Characterization of purified OMVs was achieved by scanning electron microscopy, nanoparticle tracking analysis and protein profiling. Cell viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay while apoptotic induction was measured by flow cytometry and confirmed by western blotting. The OMVs produced showed a spherical morphology, with a diameter of 137.2 ± 41 nm and a vesicular density of 7.8 × 109 particles/mL Exposure of cell monolayers to 50 μg of K. pneumoniae-OMV for 14 h resulted in approximately 25 % cytotoxicity and 41.15-41.14 % of cells undergoing early and late apoptosis. Fluorescence microscopy revealed reduced cellular density, the presence of apoptotic bodies, chromatin condensation, and nuclear membrane blebbing in residual cells. Activation of caspases -3 and -9 and dysregulation of BAX, BIM and Bcl-xL indicated the activation of mitochondria-dependent apoptosis. Furthermore, a decrease in the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase involved endoplasmic reticulum stress with the potential formation of reactive oxygen species. These findings provide evidence for the role of OMVs in apoptosis and involvement in the pathogenesis of K. pneumoniae infections
Differential Geometry of Quantum States, Observables and Evolution
The geometrical description of Quantum Mechanics is reviewed and proposed as
an alternative picture to the standard ones. The basic notions of observables,
states, evolution and composition of systems are analised from this
perspective, the relevant geometrical structures and their associated algebraic
properties are highlighted, and the Qubit example is thoroughly discussed.Comment: 20 pages, comments are welcome
Immuno-modulatory and anti-Inflammatory effects of dihydrogracilin A, a trpene derived from the marine sponge Dendrilla membranosa.
We assessed the immunomodulatory and anti-inflammatory effects of 9,11-dihydrogracilin
A (DHG), a molecule derived from the Antarctic marine sponge Dendrilla membranosa. We used
in vitro and in vivo approaches to establish DHG properties. Human peripheral blood mononuclear
cells (PBMC) and human keratinocytes cell line (HaCaT cells) were used as in vitro system, whereas
a model of murine cutaneous irritation was adopted for in vivo studies. We observed that DHG
reduces dose dependently the proliferative response and viability of mitogen stimulated PBMC.
In addition, DHG induces apoptosis as revealed by AnnexinV staining and downregulates the
phosphorylation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-B), signal
transducer and activator of transcription (STAT) and extracellular signal\u2013regulated kinase (ERK)
at late time points. These effects were accompanied by down-regulation of interleukin 6 (IL-6)
production, slight decrease of IL-10 and no inhibition of tumor necrosis factor-alpha (TNF-)
secretion. To assess potential properties of DHG in epidermal inflammation we used HaCaT cells;
this compound reduces cell growth, viability and migration. Finally, we adopted for the in vivo study
the croton oil-induced ear dermatitis murine model of inflammation. Of note, topical use of DHG
significantly decreased mouse ear edema. These results suggest that DHG exerts anti-inflammatory
effects and its anti-edema activity in vivo strongly supports its potential therapeutic application in
inflammatory cutaneous diseases
Transfer of a human gene variant associated with exceptional longevity improves cardiac function in obese type 2 diabetic mice through induction of the SDF-1/CXCR4 signalling pathway
Aims: Homozygosity for a four-missense single-nucleotide polymorphism haplotype of the human BPIFB4 gene is enriched in long-living individuals. Delivery of this longevity-associated variant (LAV) improved revascularisation and reduced endothelial dysfunction and atherosclerosis in mice through a mechanism involving the stromal cell-derived factor-1 (SDF-1). Here, we investigated if delivery of the LAV-BPIFB4 gene may attenuate the progression of diabetic cardiomyopathy. Methods and results: Compared with age-matched lean controls, diabetic db/db mice showed altered echocardiographic indices of diastolic and systolic function and histological evidence of microvascular rarefaction, lipid accumulation, and fibrosis in the myocardium. All these alterations, as well as endothelial dysfunction, were prevented by systemic LAV-BPIFB4 gene therapy using an adeno-associated viral vector serotype 9 (AAV9). In contrast, AAV9 wild-type-BPIFB4 exerted no benefit. Interestingly, LAV-BPIFB4-treated mice showed increased SDF-1 levels in peripheral blood and myocardium and up-regulation of the cardiac myosin heavy chain isoform alpha, a contractile protein that was reduced in diabetic hearts. SDF-1 up-regulation was instrumental to LAV-BPIFB4-induced benefit as both haemodynamic and structural improvements were inhibited by an orally active antagonist of the SDF-1 CXCR4 receptor. Conclusions: In mice with type-2 diabetes, LAV-BPIFB4 gene therapy promotes an advantageous remodelling of the heart, allowing it to better withstand diabetes-induced stress. These results support the viability of transferring healthy characteristics of longevity to attenuate diabetic cardiac disease
Butyrate as bioactive human milk protective component against food allergy
Background: Food allergy (FA) is a growing health problem worldwide. Effective strategies are advocated to limit the disease burden. Human milk (HM) could be considered as a protective factor against FA, but its mechanisms remain unclear. Butyrate is a gut microbiota-derived metabolite able to exert several immunomodulatory functions. We aimed to define the butyrate concentration in HM, and to see whether the butyrate concentration detected in HM is able to modulate the mechanisms of immune tolerance. Methods: HM butyrate concentration from 109 healthy women was assessed by GS-MS. The effect of HM butyrate on tolerogenic mechanisms was assessed in in vivo and in vitro models. Results: The median butyrate concentration in mature HM was 0.75 mM. This butyrate concentration was responsible for the maximum modulatory effects observed in all experimental models evaluated in this study. Data from mouse model show that in basal condition, butyrate up-regulated the expression of several biomarkers of gut barrier integrity, and of tolerogenic cytokines. Pretreatment with butyrate significantly reduced allergic response in three animal models of FA, with a stimulation of tolerogenic cytokines, inhibition of Th2 cytokines production and a modulation of oxidative stress. Data from human cell models show that butyrate stimulated human beta defensin-3, mucus components and tight junctions expression in human enterocytes, and IL-10, IFN-γ and FoxP3 expression through epigenetic mechanisms in PBMCs from FA children. Furthermore, it promoted the precursors of M2 macrophages, DCs and regulatory T cells. Conclusion: The study's findings suggest the importance of butyrate as a pivotal HM compound able to protect against FA
On the notion of composite system
The notion of composite system made up of distinguishable parties is
investigated in the context of arbitrary convex spaces.Comment: 9 pages. Comments are welcom
Opportunities and challenges for the inclusion of patient preferences in the medical product life cycle: a systematic review.
Background: The inclusion of patient preferences (PP) in the medical product life cycle is a topic of growing
interest to stakeholders such as academics, Health Technology Assessment (HTA) bodies, reimbursement agencies,
industry, patients, physicians and regulators. This review aimed to understand the potential roles, reasons for using
PP and the expectations, concerns and requirements associated with PP in industry processes, regulatory benefitrisk assessment (BRA) and marketing authorization (MA), and HTA and reimbursement decision-making.
Methods: A systematic review of peer-reviewed and grey literature published between January 2011 and March
2018 was performed. Consulted databases were EconLit, Embase, Guidelines International Network, PsycINFO and
PubMed. A two-step strategy was used to select literature. Literature was analyzed using NVivo (QSR international).
Results: From 1015 initially identified documents, 72 were included. Most were written from an academic
perspective (61%) and focused on PP in BRA/MA and/or HTA/reimbursement (73%). Using PP to improve
understanding of patients’ valuations of treatment outcomes, patients’ benefit-risk trade-offs and preference
heterogeneity were roles identified in all three decision-making contexts. Reasons for using PP relate to the unique
insights and position of patients and the positive effect of including PP on the quality of the decision-making
process. Concerns shared across decision-making contexts included methodological questions concerning the
validity, reliability and cognitive burden of preference methods. In order to use PP, general, operational and quality
requirements were identified, including recognition of the importance of PP and ensuring patient understanding in
PP studies.
Conclusions: Despite the array of opportunities and added value of using PP throughout the different steps of the
MPLC identified in this review, their inclusion in decision-making is hampered by methodological challenges and
lack of specific guidance on how to tackle these challenges when undertaking PP studies. To support the
development of such guidance, more best practice PP studies and PP studies investigating the methodological
issues identified in this review are critically needed
Dendritic Cells/Natural Killer Cross-Talk: A Novel Target for Human Immunodeficiency Virus Type-1 Protease Inhibitors
BACKGROUND:
HIV-1 Protease Inhibitors, namely PIs, originally designed to inhibit HIV-1 aspartic protease, can modulate the immune response by mechanisms largely unknown, and independent from their activity on viral replication. Here, we analyzed the ability of PIs to interfere with differentiation program of monocytes toward dendritic cell (DCs) lineage, a key process in the inflammatory response.
METHODOLOGY/PRINCIPAL FINDINGS:
Monocytes from healthy donors were isolated and induced to differentiate in vitro in the presence or absence of saquinavir, ritonavir, nelfinavir, indinavir or amprenavir (sqv, rtv, nlfv, idv, apv, respectively). These drugs demonstrated a differential ability to sustain the generation of immature DCs (iDCs) with an altered phenotype, including low levels of CD1a, CD86, CD36 and CD209. DCs generated in the presence of rtv also failed to acquire the typical phenotype of mature DCs (mDCs), and secreted lower amounts of IL-12 and IL-15. Accordingly, these aberrant mDCs failed to support activation of autologous Natural Killer (NK) cells, and resulted highly susceptible to NK cell-mediated cytotoxicity.
CONCLUSIONS/SIGNIFICANCE:
Our findings uncover novel functional properties of PIs within the DC-NK cell cross-talk, unveiling the heterogeneous ability of members of this class drugs to drive the generation of atypical monocyte-derived DCs (MDDCs) showing an aberrant phenotype, a failure to respond appropriately to bacterial endotoxin, a weak ability to prime autologous NK cells, and a high susceptibility to NK cell killing. These unexpected properties might contribute to limit inflammation and viral spreading in HIV-1 infected patients under PIs treatment, and open novel therapeutical perspectives for this class drugs as immunomodulators in autoimmunity and cancer
A narrative review of the potential pharmacological influence and safety of ibuprofen on coronavirus disease 19 (COVID-19), ACE2, and the immune system: a dichotomy of expectation and reality
The coronavirus disease 19 (COVID-19) pandemic is currently the most acute healthcare challenge in the world. Despite growing knowledge of the nature of Severe Acute Respiratory Syndrome coronavirus-2 (SARS-CoV-2), treatment options are still poorly defined. The safety of non-steroidal anti-inflammatory drugs (NSAIDs), specifically ibuprofen, has been openly questioned without any supporting evidence or clarity over dose, duration, or temporality of administration. This has been further conflicted by the initiation of studies to assess the efficacy of ibuprofen in improving outcomes in severe COVID-19 patients. To clarify the scientific reality, a literature search was conducted alongside considerations of the pharmacological properties of ibuprofen in order to construct this narrative review. The literature suggests that double-blind, placebo-controlled study results must be reported and carefully analysed for safety and efficacy in patients with COVID-19 before any recommendations can be made regarding the use of ibuprofen in such patients. Limited studies have suggested: (i) no direct interactions between ibuprofen and SARS-CoV-2 and (ii) there is no evidence to suggest ibuprofen affects the regulation of angiotensin-converting-enzyme 2 (ACE2), the receptor for COVID-19, in human studies. Furthermore, in vitro studies suggest ibuprofen may facilitate cleavage of ACE2 from the membrane, preventing membrane-dependent viral entry into the cell, the clinical significance of which is uncertain. Additionally, in vitro evidence suggests that inhibition of the transcription factor nuclear factor-κB (NF-kB) by ibuprofen may have a role in reducing excess inflammation or cytokine release in COVID-19 patients. Finally, there is no evidence that ibuprofen will aggravate or increase the chance of infection of COVID-19
Opportunities and challenges for the inclusion of patient preferences in the medical product life cycle: a systematic review
BACKGROUND: The inclusion of patient preferences (PP) in the medical product life cycle is a topic of growing interest to stakeholders such as academics, Health Technology Assessment (HTA) bodies, reimbursement agencies, industry, patients, physicians and regulators. This review aimed to understand the potential roles, reasons for using PP and the expectations, concerns and requirements associated with PP in industry processes, regulatory benefit-risk assessment (BRA) and marketing authorization (MA), and HTA and reimbursement decision-making. METHODS: A systematic review of peer-reviewed and grey literature published between January 2011 and March 2018 was performed. Consulted databases were EconLit, Embase, Guidelines International Network, PsycINFO and PubMed. A two-step strategy was used to select literature. Literature was analyzed using NVivo (QSR international). RESULTS: From 1015 initially identified documents, 72 were included. Most were written from an academic perspective (61%) and focused on PP in BRA/MA and/or HTA/reimbursement (73%). Using PP to improve understanding of patients' valuations of treatment outcomes, patients' benefit-risk trade-offs and preference heterogeneity were roles identified in all three decision-making contexts. Reasons for using PP relate to the unique insights and position of patients and the positive effect of including PP on the quality of the decision-making process. Concerns shared across decision-making contexts included methodological questions concerning the validity, reliability and cognitive burden of preference methods. In order to use PP, general, operational and quality requirements were identified, including recognition of the importance of PP and ensuring patient understanding in PP studies. CONCLUSIONS: Despite the array of opportunities and added value of using PP throughout the different steps of the MPLC identified in this review, their inclusion in decision-making is hampered by methodological challenges and lack of specific guidance on how to tackle these challenges when undertaking PP studies. To support the development of such guidance, more best practice PP studies and PP studies investigating the methodological issues identified in this review are critically needed
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