Altered intercellular communication in lung fibroblast cultures from patients with idiopathic pulmonary fibrosis.

RATIONALE: Gap junctions are membrane channels formed by an array of connexins which links adjacent cells realizing an electro- metabolic synapse. Connexin-mediated communication is crucial in the regulation of cell growth, differentiation, and development. The activation and proliferation of phenotypically altered fibroblasts are central events in the pathogenesis of idiopathic pulmonary fibrosis. We sought to evaluate the role of connexin-43, the most abundant gap-junction subunit in the human lung, in the pathogenesis of this condition. METHODS: We investigated the transcription and protein expression of connexin-43 and the gap-junctional intercellular communication (GJIC) in 5 primary lung fibroblast lines derived from normal subjects (NF) and from 3 histologically proven IPF patients (FF). RESULTS: Here we show that connexin-43 mRNA was significantly reduced in FF as demonstrated by standard and quantitative RT-PCR. GJIC was functionally evaluated by means of flow-cytometry. In order to demonstrate that dye spreading was taking place through gap junctions, we used carbenoxolone as a pharmacological gap-junction blocker. Carbenoxolone specifically blocked GJIC in our system in a concentration dependent manner. FF showed a significantly reduced homologous GJIC compared to NF. Similarly, GJIC was significantly impaired in FF when a heterologous NF line was used as dye donor, suggesting a complete defect in GJIC of FF. CONCLUSION: These results suggest a novel alteration in primary lung fibroblasts from IPF patients. The reduced Cx43 expression and the associated alteration in cell-to-cell communication may justify some of the known pathological characteristic of this devastating disease that still represents a challenge to the medical practice.

Brugada-like electrocardiographic pattern: a challenge for the clinician.

A right bundle branch block with ST-segment elevation in the V1-V3 leads in characteristic coved or saddleback configuration may be encountered as an incidental finding. However, not all patients with a Brugada-like electrocardiographic pattern are affected by the Brugada syndrome; in fact, this pattern may also be found in healthy individuals. Whether symptomatic patients affected by the syndrome are at a high risk of developing life-threatening ventricular arrhythmias and should immediately receive an automatic, implantable defibrillator is open to debate, as is the clinical management of asymptomatic patients, because data from the scientific literature are controversial. Implications of the diagnosis and the treatment of this category of patients are discussed.

The effect of fexofenadine on expression of intercellular adhesion molecule 1 and induction of apoptosis on peripheral eosinophils.

The role of eosinophils in the pathogenesis of allergic disorders has been established by several studies. Recently, it has been suggested that second-generation antihistamines, widely used to relieve allergic symptoms, may have anti-inflammatory effects. To assess the possible anti-inflammatory activity of fexofenadine, a selective H1-receptor antagonist, we evaluated its capacity to modulate the expression of adhesion molecules leukocyte function-associated antigen (LFA) 1 and intracellular adhesion molecule (ICAM) 1 on eosinophil surface and to induce apoptosis of eosinophils. To analyze the expression of adhesion molecules, eosinophils from healthy donors were cultured in the presence of interferon gamma and tumor necrosis factor alpha with various concentrations of fexofenadine, incubated with monoclonal antibodies anti-ICAM-1 and LFA-1 and then analyzed by flow cytometry. To evaluate apoptosis of eosinophils, cells stimulated with interleukin-5, in the presence of different concentrations of fexofenadine, have been incubated with a phosphatidylserine-binding protein (annexin V) fluorescein isothiocyanate conjugated and then analyzed by flow cytometry. Apoptosis was evaluated as a percentage of annexin V+ cells. In this study, fexofenadine did not cause any significant changes in the expression of LFA-1 but was shown to be able to inhibit the expression of ICAM-1 at concentrations between 10(-3) and 10(-4) M. Moreover, concentrations of fexofenadine from 10(-3) to 6 x 10(-4) M induced a significant increment in the percentage of apoptotic cells. Our findings indicate the possibility of obtaining relevant anti-inflammatory pharmacologic effects, other than antihistamine activity, by fexofenadine, such as inhibition of ICAM-1 expression and induction of eosinophil apoptosis.