Biomedical subjects

Brunella Perfetto

Publications and source records attributed to Brunella Perfetto.

6 recordsLinked to original sources

PubMed2006

Lactoferrin downregulates pro-inflammatory cytokines upexpressed in intestinal epithelial cells infected with invasive or noninvasive Escherichia coli strains.

Intestinal epithelial cells are able to differentially interact with commensal or pathogenic microorganisms, triggering a physiological or destructive inflammation, respectively. To mimic commensal-enteroinvasive bacteria-host cell interaction, we infected Caco-2 cells with noninvasive Escherichia coli HB101 and with recombinant invasive E. coli HB101(pRI203). Using DNA microarray mRNA profiling and ELISA assays, we studied the expression of several cytokine and cytokine-related genes in infected Caco-2 cells in the absence or presence of bovine lactoferrin (bLf). Infection of Caco-2 cells with the noninvasive strain induced a slight increase in the expression of interleukin 8 (IL-8), whereas infection with invasive E. coli HB101(pRI203) induced a significant increase in the expression of IL-8 as well as other pro-inflammatory cytokines. The addition of bLf, in native- or holo-form, did not influence expression of cytokine genes by uninfected Caco-2 cells, but it decreased expression of IL-8 by cells infected with E.coli HB101. Moreover, except for IL-8, bLfs dramatically downregulated pro-inflammatory cytokines upexpressed by Caco-2 cells infected with the invasive strain. Although IL-8 was decreased by bLfs, it remained upregulated, suggesting that it could be a signal of persistence of intracellular bacteria. The bLf ability to reduce expression of some pro-inflammatory cytokines, which appears independent of its iron saturation, might represent an important natural mechanism in regulating epithelial cell responses to pathogenic bacteria and in limiting cell damage and the spread of infections.

Animals↗

PubMed2005

Slime-producing Staphylococcus epidermidis and S. aureus in acute bacterial conjunctivitis in soft contact lens wearers.

In recent years, an increase in ocular pathologies related to soft contact lens has been observed. The most common infectious agents were Staphylococcus spp. Some strains produce an extracellular polysaccharidic slime that can cause severe infections. Polysaccharide synthesis is under genetic control and involves a specific intercellular adhesion (ica) locus, in particular, icaA and icaD genes. Conjunctival swabs from 97 patients with presumably bacterial bilateral conjunctivitis, wearers of soft contact lenses were examined. We determined the ability of staphylococci to produce slime, relating it to the presence of icaA and icaD genes. We also investigated the antibiotic susceptibility and Pulsed Field Gel Electrophoresis (PFGE) patterns of the clinical isolates. We found that 74.1% of the S. epidermidis strains and 61.1% of the S. aureus strains isolated were slime producers and showed icaA and icaD genes. Both S. epidermidis and S. aureus slime-producing strains exhibited more surface hydrophobicity than non-producing slime strains. The PFGE patterns overlapped in S. epidermidis strains with high hydrophobicity. The similar PFGE patterns were not related to biofilm production. We found scarce matching among the Staphylococcus spp. studied, slime production, surface hydrophobicity and antibiotic susceptibility.

Adolescent↗

PubMed2004

In vitro evaluation of matrix metalloproteinases as predictive testing for nickel, a model sensitizing agent.

The identification of potential damage due to chemical exposure in the workplace is a major health and regulatory concern. Traditional tests that measure both sensitization and elicitation responses require the use of animals. An alternative to this widespread use of experimental animals could have a crucial impact on risk assessment, especially for the preliminary screening of new molecules. We developed an in vitro model for the screening of potential toxic compounds. Human keratinocytes (HaCat) were used as target cells while matrix metalloproteinases (MMP) were selected as responders because they are key enzymes involved in extracellular matrix (ECM) degradation in physiological and pathological conditions. Chemical exposure was performed using nickel sulphate as a positive tester. Nickel contact induced upregulation of MMP-2 and IL-8 mRNA production. Molecular activation occurred even at very low nickel concentrations even though no phenotypic changes were observed. MMP-9 accumulation was found in the medium of treated cells with respect to controls. These observations led to the hypothesis that even minimal exposure can accumulate transcriptional activity resulting in long-term clinical signs after contact. Our simple in vitro model can be applied as a useful preliminary complement to the animal studies to screen the effects of new potential toxic compounds.

Animal Testing Alternatives↗

PubMed2004

Interferon-gamma cooperates with Helicobacter pylori to induce iNOS-related apoptosis in AGS gastric adenocarcinoma cells.

Helicobacter pylori colonizes the human stomach and causes gastric disease. The resulting gastric damage is a multi-step process involving several molecular factors and different target cells. Th1 cytokines released by neutrophils and lymphoid cells that infiltrate gastric mucosa, nitric oxide production and inducible nitric oxide synthase (iNOS) are associated with immune activation and tissue injury. Many other molecular processes such as apoptosis, as well as angiogenic factors and integrins, are involved in H. pylori pathogenesis. We used cancer gastric cells AGS and MKN as experimental models to evaluate apoptotic rates, iNOS gene expression with and without the presence of interferon-gamma (IFN-gamma), placenta growth factor gene expression and alphav modulation. Our results show that AGS cells stimulated with H. pylori underwent apoptosis. Moreover, the addition of IFN-gamma caused a further increase in iNOS gene expression and in the apoptotic rates. We also found early modulation in PlGF and alphav expression, and noted that p53 and bax gene expression was involved in the apoptotic process. Taken together, these findings demonstrate that H. pylori employs a series of mechanisms to avoid the host defense and cause gastric mucosa damage. One H. pylori pathogenic mechanism for causing gastric damage is the induction of iNOS-dependent apoptosis that is strongly enhanced by IFN-gamma. Thus, data obtained indicate that Th1 cytokines such as IFN-gamma, via modulation of iNOS gene expression, may contribute to an increase in the pathogenicity of H. pylori infections.

Apoptosis↗

PubMed2003

Bacterial components induce cytokine and intercellular adhesion molecules-1 and activate transcription factors in dermal fibroblasts.

This study investigated the effect of various structural components of Gram-positive (lipotheichoic acid and protein A) and Gram-negative (porins and lipopolysaccharide) bacteria on human dermal fibroblasts. Fibroblasts are important effector cells which have a potential role in augmenting the inflammatory response in various diseases. In this study we present a profile of TNF-alpha, IL-6 and IL-8, the expression of intercellular adhesion molecules (ICAM-1) and the activation of transcriptional nuclear factor NF-kB and AP-1 in human dermal fibroblasts stimulated by bacterial surface components. Compared to the controls, increased ICAM-1, IL-6 and IL-8 gene expression after stimulation of LPS and porins at 2 and 4 h was more evident than that obtained following stimulation of LTA and PA. Gene expression was also associated with the production of cytokine proteins in culture supernatants. TNF-alpha gene expression remained undetectable. Moreover, LPS and porin treatments determined IkBalpha phosphorylation and degradation in human dermal fibroblasts and the subsequent activation of nuclear factors NF-kB and AP-1. These data suggest the importance of such stimuli in the first step of the inflammatory process, as well as the important role played by fibroblasts in skin inflammatory disease.

Adult↗

PubMed2002

Cytokine pattern in blister fluid and sera of patients with pemphigus.

BACKGROUND: Pemphigus is a chronic auto-immune blistering disease with four main variants, i.e. pemphigus vulgaris (PV), foliaceus (PF), erythematosus (PE) and vegetans. The common histological feature of this disease is acantholysis. OBJECTIVE: The aim of this study was to compare levels of some cytokines in blister fluid and sera of patients with pemphigus, using as control blister fluid of patients with bullous pemphigoid (BP) and bullous contact dermatitis (BCD). METHODS: Using an immuno-enzymatic assay (ELISA), we tested 16 sera and 6 blister fluids of patients with various forms of pemphigus (13 with PV, 1 with PF, 2 with PE), the sera of 16 healthy control subjects, 5 blister fluids of patients with BP and 5 blister fluids of patients with BCD, for the presence of some cytokines (IL-10, IL-8 and IFN-gamma). Intercellular antibodies were searched for and titred; desmoglein 1 and 3 antibody levels were independently evaluated to compare them with the severity of both cutaneous and oral involvement. RESULTS: The levels of IL-10 in the sera of patients with pemphigus were below the detection limits. IL-8 was significantly increased only in 4 samples of sera from pemphigus patients compared with controls, while IFN-gamma was detected at low levels in almost all patients compared with sera of controls. The cytokine levels in blister fluid of patients with pemphigus were significantly higher than in the sera. There was a difference between the expression of cytokines in blister fluid of control patients with BP and BCD compared with those of pemphigus patients. CONCLUSION: This report discusses the anti-inflammatory role played by IL-10 in the chronic form of pemphigus and the hypothesis of a possible role of IL-8 in neutrophil and lymphocyte-monocyte recruitment.

Adolescent↗