Peripheral monocytes from diabetic patients with coronary artery disease display increased bFGF and VEGF mRNA expression

BACKGROUND: Macrophages can produce vascular endothelial growth factor (VEGF) in response to hypoxia, transforming growth factor β1 (TGF-β1), angiotensin II, basic fibroblast growth factor (bFGF), and interleukin-1. These factors have been found in the serum of coronary artery disease (CAD) patients as well as in atherosclerotic lesions. The aim of the present study was to test the hypothesis that the expression of VEGF, TGF-β1 and bFGF in peripheral monocytes and lymphocytes is related to CAD. METHODS: Human Mononuclear cells and lymphocytes from peripheral blood were isolated from 53 donors undergoing angiography. Seventeen were found to be healthy and 36 were diagnosed with CAD. The respective mRNAs were extracted and quantified. RESULTS: The statistical analysis revealed a significant increase of the basal level expression for macrophage VEGF and bFGF in the CAD SA (stable angina) patient group compared to the noCAD (control) (p = 0.041 and p = 0.022 respectively) and CAD UA (unstable angina) (p = 0.024 and p = 0.005 respectively) groups, which was highly dependent on the diabetic status of the population. Furthermore, we demonstrated with an in vitro cell culture model that the levels of VEGF and bFGF in monocytes of healthy donors are not affected by short term exposure to increased glucose levels (usually observed in the diabetic patients) and/or statin. CONCLUSION: Our findings display a statistically significant association of the increased VEGF and bFGF levels in peripheral monocytes, with stable angina and diabetes in coronary artery disease. The results give new insight to CAD and the impaired collateral vessel formation in diabetics

HIV-1 infection: Is it time to reconsider our concepts?

The long asymptomatic phase of HIV infection is critical in the progression to AIDS. It probably reflects an ancestral relationship with lentiviruses stemming from the primate-simian immunodeficiency virus evolutionary pathway leading to an idiosyncratic immune tolerance, which needs to be understood if effective vaccines are to be rationally designed. The majority of CD4(+) T cells that die due to HIV-1 in the asymptomatic phase are not infected with the virus. Transmission of the predominant HIV-1 R5 variants to T cells is mediated by infected monocyte-derived macrophages. The two cell populations come into intimate contact mainly in the lymph nodes during antigen presentation where there is also active viral replication. We propose that HIV exploits antigen presentation to access target T cells and evade immune surveillance. This is achieved at the assembly point of an immunological synapse between an antigen presenting, HIV-1-infected macrophage and a responding effector/memory CD4(+) T cell. Viral envelope gp120 glycoproteins proximal to MHC 11 molecules cross-link with T cell CD4 molecules, thus establishing a supra molecular immuno-viral synapse. The interaction results in conformational changes of gp120 exposing its V3 domain. Ionic interaction of this domain with the synapse-recruited chemokine receptor CCR5 dimerizes the receptor triggering intracellular signals that contribute to T cell receptor transactivation pathways and subsequent enhancement of T cell activation. HIV-downregulated MHC H gives weak immune complexes. Disruption of the immunoviral synapse before completion of cell entry is a frequent outcome condemning the responding T cell to a premature activation-induced T cell death. Information on the assembly, mechanistic and functional interactions at the immuno-viral synapses may well assist in elucidating new strategies to combat HIV infection

IL-1 cytokines in cardiovascular disease: Diagnostic, prognostic and therapeutic implications

Interleukins (ILs) are key mediators in the chronic vascular inflammatory response underlying several aspects of cardiovascular disease. Due to their powerful pro-inflammatory potential, and the fact that they are highly expressed by almost all cell types actively implicated in atherosclerosis, members of the IL-I cytokine family were the first to be investigated in the field of vessel wall inflammation. The IL-1 family is comprised of five proteins that share considerable sequence homology: IL-1α, IL-1β, IL-1 receptor antagonist (IL-1Ra), IL-18 (also known as IFNγ-inducing factor), and the newly discovered ligand of the ST2L receptor, IL-33. Expression of IL-1s and their receptors has been demonstrated in atheromatous tissue, and serum levels of IL-1-cytokines have been correlated with various aspects of cardiovascular disease and their outcome. In vitro studies have confirmed pro-atherogenic properties of IL-1α, IL-1β and IL-18 such as, upregulation of endothelial adhesion molecules, the activation of macrophages and smooth muscle cell proliferation. In contrast with this, IL-1Ra, a natural antagonist of IL-1, possesses anti-inflammatory properties, mainly through the endogenous inhibition of IL-1 signaling. IL-33 was identified as a functional ligand of the, till recently, orphan receptor, ST2L. IL-33/ST2L signaling has been reported as a mechanically activated, cardioprotective paracrine system triggered by myocardial overload. As the roles of individual members of the IL-1 family are being revealed, novel therapies aimed at the modulation of interleukin function in several aspects of cardiovascular disease, are being proposed. Several approaches have produced promising results. However, none of these approaches has yet been applied in clinical practice. © 2008 Bentham Science Publishers Ltd

A study of zearalenone cytotoxicity on human peripheral blood mononuclear cells

The mycotoxin zearalenone (ZEA) is a common contaminant of all major cereal grains worldwide with estrogenic and anabolic activity. We investigated the in vitro cytopathic effects of ZEA on freshly isolated human peripheral blood mononuclear cells (PBMC) in relation to proliferation and cell death patterns of untreated and mitogen-activated cells. The higher concentration of 30 mu g/ml ZEA was found to totally inhibit T and B lymphocyte proliferation from the stimulation with phytohemagglutinin and pokeweed mitogen. The inhibitory effects of ZEA were further related to cell necrosis/apoptosis. Flow cytometry analysis showed a distinct necrotic effect on PBMC, irrespective of mitogen stimulation, whereas apoptotic activity was less evident. Necrosis was observed in both the lymphocyte and monocyte/granulocyte gates. Measurements of ZEA-induced intracellular calcium ion (Ca2+) mobilization showed an increase of both Ca2+ levels and the number of cells with high Ca2+ only in the monocyte/granulocyte gated cells. Using phenylmethyl sulfonyl fluoride (PMSF), a serine protease inhibitor, and ammonium chloride (NH4Cl), a lysosomal inhibitor, both associated with cell necrosis inhibition, we showed that PMSF at 0.05 mM and NH4Cl at 1 and 10 mM reduced the cytopathic effects induced by 30 mu g/ml ZEA, whereas apoptosis was less affected. Expose of PBMC to 1 mu g/ml ZEA did not alter the viability of the cells. Our results suggest that high ZEA concentrations in the blood may well exert cytotoxic effects that merit further investigation. (c) 2006 Elsevier Ireland Ltd. All rights reserved

Polymorphisms of Cx(3)CR1 and CXCR6 receptors in relation to HAART therapy of HIV type 1 patients

The chemokine polymorphisms CXCR6-3E/K, In1.1T/C, H7 haplotype, CX(3)CR1-V249I, and CX(3)CR1-T280M have been shown to affect the course of HIV infection. We studied their influence on immunologic and virologic response to HAART in a group of 143 HIV-1 patients. We performed Kaplan-Meier analysis using the following end-point criteria: (1) time from HAART initiation to undetectable viral load (VL < 50 copies/ml), (2) maximum duration of viral suppression, (3) time from HAART administration until CD4 elevation above 200 cells/mu l for patients with baseline CD4 below 200 cells/mu l and above 500 cells/mu l for patients with baseline CD4 between 200 and 500 cells/mu l, respectively, and (4) time from HAART initiation until CD4 reduction below baseline values. Our results revealed an improved immunologic response to HAART in patients with the CX(3)CR1-249I or CX(3)CR1-280M allele. On the contrary, patients with initial VL suppression due to HAART showed a faster virologic failure in the presence of the CXCR6-3K allele. The In1.1T/C polymorphism and H7 haplotype did not reveal any specific effect on HAART response

Molecular diagnostic tools in mycobacteriology

Although the diagnosis of mycobacteriosis and susceptibility testing are still primarily based on conventional methods (staining, culture, biochemical analysis, proportional method), a series of molecular assays are increasingly introduced and incorporated in the workflow of clinical mycobacteriology laboratories worldwide. These assays are rapid and offer high sensitivities and specificities. In the present review, we describe the molecular assays concerning the early detection of Mycobacteria in clinical specimens, the identification of mycobacterial species, the detection of drug resistance and the typing for epidemiological investigations. (C) 2008 Elsevier B.V. All rights reserved

Electrostatic modeling of peptides derived from the V3-loop of HIV-1 gp120: Implications of the interaction with chemokine receptor CCR5

Infection of CD4(+) T cells by macrophage-tropic HIV-1 strains involves interaction of viral gp 120 with the host cell chemokine receptor CCR5. The principle neutralizing determinant (PND) of the V3-loop of the HIV-1 gp120 was investigated for its interaction with CCR5 by computational modeling methods at atomic resolution and electrostatic calculations to complement experimental findings. The study focused on the recognition step and examined possible peptide-peptide interactions between various PND-derived peptides from the V3-loop and the N-terminal (Nt) domain of CCR5. These recognition interactions are possible because of the complementary character of the spatial distribution of the predominantly positive electrostatic potentials of the PND-derived peptides and the predominantly negative electrostatic potential of the CCR5Nt domain. The CCR5Nt appears more amenable to interaction with the V3 peptides, than the other CCR5 extracellular domains (ECL), because of its length and the domination of its negative electrostatic potential. On the contrary, ECL2 possesses a predominantly positive electro-static potential. There are positive patches in Nt and negative patches in ECL2, which, following the non-specific recognition of the V3-loop by CCR5 and with the expected local structural rearrangements to facilitate specific binding, may be contributing to the stabilization of the complex. A sequential two-step specific binding, involving different extracellular domains, is conceivable. Although the electrostatic potentials may play a role in a V3-CCR5 interaction, a more specific model cannot be derived in the absence of a three-dimensional structure of a gp 120/CD4/CCR5 complex

Evaluation of specific immune responses to BoNT/A and tetanus toxoid in patients undergoing treatment for neurologic disorders

Botulinum neurotoxins (BoNTs) are used in the treatment of many neurological disorders. The primary structure of BoNTs shows a high degree of homology with the tetanus neurotoxin, the toxoid of which is used as a vaccine. Because of the potential cross-reactivity between these toxins, we investigated the effects of Botulinum neurotoxin A (BoNT/A) and tetanus toxoid on peripheral blood mononuclear cells (PBMC) and the corresponding serum antibody levels, in twenty patients who had been treated with BoNT/A. We observed very low PBMC immunostimulation by BoNT/A at the tested dose (15 units/ml), as demonstrated by the low lymphocyte proliferation, and the absence of detectable antibodies cross-reacting with tetanus. However, exposure of PBMC from tetanus-sensitized patients to both neurotoxins showed that BoNT/A exerted a co stimulatory effect on tetanus-stimulated cells. Interestingly, in flow cytometry analysis, BoNT/A seemed to also alter the ratio of naïve (CD45RA): memory/effector (CD45RO) T lymphocyte subsets, in favour of CD45RO. These preliminary data give a new insight on the potential immune crossreactivity between the two antigens. In view of the wide use of both neurotoxins, these immunotoxic effects merit a more detailed investigation. © 2012 Bentham Science Publishers