Toll-like receptor 2 deficiency leads to delayed exacerbation of ischemic injury

ABSTRACT: BACKGROUND: : Using live imaging approach we have previously shown that microglia activation after stroke is characterized by marked and long-term induction of the Toll like Receptor 2 (TLR2) biophotonic signals. However, the role of TLR2 (and potentially other TLRs), beyond the acute innate immune response and an early neuroprotection against ischemic injury is not well understood. METHOD: S: The TLR2 -/- mice were subjected to transient middle cerebral artery occlusion (MCAO) followed by different reperfusion times. Analyses assessing microglial activation profile/innate immune response were performed using in situ hybridization, immunohistochemistry analysis, flow cytometry and inflammatory cytokine array. The effects of the TLR2 deficiency on the evolution of ischemic brain injury were analyzed using a cresyl violet staining of brain sections with appropriate lesion size estimation. RESULTS: : Here we report that TLR2 deficiency markedly affects post-stroke immune response resulting in delayed exacerbation of the ischemic injury. The temporal analysis of the microglia/macrophage activation profiles in TLR2 -/- mice and age-matched controls revealed reduced microglia/macrophage activation after stroke, reduced capacity of resident microglia to proliferate as well as decreased levels of MCP-1 and consequently lower levels of CD45high/CD11b+ expressing cells as shown by flow cytometry analysis. Importantly, although acute ischemic lesions (24-72hrs) were smaller in TLR2 -/- mice, the observed alterations in innate immune response were more pronounces at later time-points (at day 7) after initial stroke, which finally resulted in delayed exacerbation of ischemic lesion leading to larger chronic infarctions as compared to WT mice. Moreover, our results revealed that TLR2 deficiency is associated with significant decrease in the levels of neurotrophic/antiapoptotic factor IGF-1, expressed by microglia in the areas in- and around ischemic lesion. CONCLUSION: Altogether our results clearly suggest that optimal and timely microglial activation/innate immune response is needed to limit neuronal damage after stroke.     

CD4 T Lymphocyte-mediated lung disease: steady state between pathological and tolerogenic immune reactions

Although considerable evidence indicates a role for CD4(+) T lymphocytes (T cells) in airway inflammation, little data exist regarding the mechanisms underlying the induction and regulation of CD4(+) T cell reactivity to lung-specific antigens. To dissect the immunologic and molecular mechanisms of CD4(+) T cell dysregulation, reactivity to a self-antigen expressed in the lung of mice bearing a major histocompatibility complex class-II-restricted T cell receptor specific for this antigen was studied. Transgenic mice developed a progressive interstitial pneumonitis characterized by massive lymphocytic and plasmacytic infiltration of interalveolar septa, a clinical picture closely resembling some of the interstitial lung diseases. Pulmonary inflammation reached a plateau state in older mice with prominent formation of lymphoid follicles but reduced interstitial infiltration. Extensive immunologic characterization of self-reactive CD4(+) T cells isolated from the inflamed lung suggested the induction of regulatory T cells in the site of inflammation. Moreover, inflammation was accompanied by broad changes in the gene expression pattern toward a profile partially resembling that of activated, but strikingly, also that of regulatory CD4(+) T cells. Together our data provide important insights into functional and molecular alterations being associated with the induction and/or regulation of T cell-mediated pulmonary inflammation.     

Lipid profile and atherogenic indices in patients with stable chronic obstructive pulmonary disease

Background and aimsLimited number of studies investigated lipid profile in chronic obstructive pulmonary disease (COPD) with inconsistent results. This study aimed to investigate lipid parameters in sera of patients with stable COPD and their associations with disease severity, smoking, comorbidities and therapy.Methods and resultsThe study included 137 COPD patients and 95 controls. Triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were assessed. Non-HDL-C (NHC), atherogenic coefficient (AC), TG/HDL-C, atherogenic index of plasma (AIP), Castelli's risk index I and II (CRI-I, CRI-II), and monocyte to HDL ratio (MHR) were calculated.HDL-C and MHR were increased, while other lipid parameters and indices were decreased in COPD patients compared to healthy individuals. Smoking did not influence lipid parameters. However, lipid profile was altered only in more severe disease stages. AC, CRI-I and CRI-II showed positive association with lung function parameters in COPD patients, and negative with COPD multicomponent indices (ADO, BODCAT, BODEx, CODEx and DOSE). Combined model that included CRI-II, C-reactive protein, fibrinogen and white blood cells showed great diagnostic performances, and correctly classified 72% of study participants with an AUC of 0.800 (0.742–0.849), P < 0.001. Bronchodilator monotherapy and statins have opposite impact on TC, LDL-C and NHC, while TG, TG/HDL-C and AIP were increased in COPD patients with cardiovascular diseases.ConclusionLipid disbalance is present in COPD, and it seems to occur later as the disease progresses. Further studies are needed to illuminate the underlying mechanism of dyslipidaemia.     

Intradiscal application of hyaluronic acid in the non-human primate lumbar spine: radiological results

Prospectively, with randomized segment-treatment assignment, and with blinded evaluators, lumbar motion segments in Cercopithecus monkeys were analyzed for macroscopic and radiological changes 24 weeks after nucleotomy and nucleotomy with additional intradiscal application of different hyaluronic acid formulations versus untreated control segments. The objective was to find out whether hyaluronic acid is able to influence the degenerative cascade in nonhuman primates after nucleotomy. In a similar procedure, hyaluronic acid has proven to decrease degeneration after nucleotomy in a Minipig model. This is the first such study ever undertaken in primates, thus trying to overcome the known limitations of non-primate spine models. Twenty monkeys with four segments each obtained nucleotomy in three segments and solely exposure of another control segment. Nucleotomy was performed from a transpsoatic retroperitoneal approach. Preoperative radiographs and follow-up radiographs, magnetic resonance imaging (MRI), computed tomography (CT), Q-CT with bone mineral density measurements and three-dimensional reconstruction were obtained and analyzed qualitatively and quantitatively. Segments with high-molecular-weight hyaluronic acid (Hylan G-F 20) application proved to be significantly superior over those with a standard nucleotomy in radiographs, MR images, CT scans, and macroscopic appearance at follow-up. Control segments remained unaffected. Interdependence between the different methods validated the utilized methods of quantitative radiological assessment of degeneration. Hylan G-F 20 appears to be a possible adjunct in reducing postoperative degeneration in an animal nucleotomy model. It deserves further evaluation, despite the fact that the mechanisms of its effects are still speculative.     

Ready for antiretroviral therapy? Therapy decision making experiences of persons living with HIV

Readiness for therapy of people living with HIV is of major importance in the process of antiretroviral decision making. This qualitative study is part of a prospective multicentre investigation describing readiness for antiretroviral therapy (ART) and decision making in HIV-infected patients. The qualitative results present the daily experiences of people living with HIV in the treatment decision making process related to starting or changing ART. Based on a critical hermeneutic research design, interviews with twelve persons have been conducted. Two main categories were generated: "dealing with oneself and others" and "understanding and being understood". They describe the dialectical process of decision making with a focus on interactions with others. This process includes four themes: illness beliefs, health perspectives, therapy beliefs, life perspectives. The findings of this study reveal that partnerships of health care providers with HIV-infected patients are necessary for treatment decisions. Moreover; it is of major importance for health care providers to include patients' experiences and expertise and to allow time for the different dialogues.     

Cell-autonomous and systemic context-dependent functions of iron regulatory protein 2 in mammalian iron metabolism

Mice with total and constitutive iron regulatory protein 2 (IRP2) deficiency exhibit microcytosis and altered body iron distribution with duodenal and hepatic iron loading and decreased iron levels in splenic macrophages. To explore cell-autonomous and systemic context-dependent functions of IRP2 and to assess the systemic consequences of local IRP2 deficiency, we applied Cre/Lox technology to specifically ablate IRP2 in enterocytes, hepatocytes, or macrophages, respectively. This study reveals that the hepatic and duodenal manifestations of systemic IRP2 deficiency are largely explained by cell-autonomous functions of IRP2. By contrast, IRP2-deficient macrophages from otherwise IRP2-sufficient mice do not display the abnormalities of macrophages from systemically IRP2-deficient animals, suggesting that these result from IRP2 disruption in other cell type(s). Mice with enterocyte-, hepatocyte-, or macrophage-specific IRP2 deficiency display normal red blood cell and plasma iron parameters, supporting the notion that the microcytosis in IRP2-deficient mice likely reflects an intrinsic defect in hematopoiesis. This work defines the respective roles of IRP2 in the determination of critical body iron parameters such as organ iron loading and erythropoiesis.