Epigenetics of osteoarticular diseases: recent developments.

A variety of osteoarticular conditions possess an underlying genetic aetiology. Large-scale genome-wide association studies have identified several genetic loci associated with osteoarticular conditions, but were unable to fully account for their estimated heritability. Epigenetic modifications including DNA methylation, histone modification, nucleosome positioning, and microRNA expression may help account for this incomplete heritability. This articles reviews insights from epigenetic studies in osteoarticular diseases, focusing on osteoarthritis, but also examines recent advances in rheumatoid arthritis, osteoporosis, systemic lupus erythematosus (SLE), ankylosing spondylitis, and sarcoma. Genome-wide methylation studies are permitting identification of novel candidate genes and molecular pathways, and the pathogenic mechanisms with altered methylation status are beginning to be elucidated. These findings are gradually translating into improved understanding of disease pathogenesis and clinical applications. Functional studies in osteoarthritis, rheumatoid arthritis, and SLE are now identifying downstream molecular alterations that may confer disease susceptibility. Epigenetic markers are being validated as prognostic and therapeutic disease biomarkers in sarcoma, and clinical trials of hypomethylating agents as treatments for sarcoma are being conducted. In concert with advances in throughput and cost-efficiency of available technologies, future epigenetic research will enable greater characterisation and treatment for both common and rare osteoarticular diseases.

COPD treatment: real life and experimental effects on peripheral NK cells, their receptors expression and their IFN-γ secretion.

A role in pulmonary immunity has been ascribed to Natural Killer (NK) cells and several in vitro studies have shown a corticosteroid-induced inhibition of NK cells mediated cytotoxicity. Several clinical trials on chronic obstructive pulmonary disease (COPD) have suggested a relationship between COPD treatment and occurrence of respiratory infections. Aims of our study were to investigate if real life COPD treatment affects peripheral blood NK cells total count and their receptors expression and to assess if different doses of formoterol and budesonide, administered alone or in combination, are able to modulate the surface expression of activating (NKp30, NKp44, NKp46 and NKG2D) and inhibitory (KIR2DL2/L3, KIR3DL1 and NKG2A) receptors on peripheral blood NK cells of COPD patients. Moreover, we evaluated the potential effect of treatment with budesonide and/or formoterol on IFN-γ secretion in vitro. NK cells were isolated from peripheral blood of 7 healthy volunteers, 9 chronic bronchitis (CB) and 11 COPD patients. Total NK cells count and activating and inhibitory receptors expression were evaluated. NK cells were cultured for 20h in 96-well plates with IL-2 (100IU/ml)+IL-12 (2.5ng/ml), with or without budesonide (Bud; 1 and 0.01µM) and formoterol (For; 30 and 0.3nM) alone or in combination. Cells were analyzed by flow cytometry and IFN-γ was measured in cell supernatants by ELISA test. No difference between real life treated COPD, CB and healthy subjects was found concerning NK total count and NK cell receptors expression. When cells were stimulated over night with cytokines and treated with drugs, only NKG2D receptor was modulated. Its expression was significantly downregulated by budesonide alone and in combination with formoterol in COPD patients. IFN-γ production induced by stimulation with IL-2+IL-12 was decreased in a highly significant way (p<0.01) by all treatments in all groups. Even if in vitro experiments with budesonide, alone or in combination with formoterol, showed a modulation of NKG2D receptor expression and IFN-γ production, our ex vivo results show that real life LABA and ICS treatment does not influence peripheral NK cells count and their receptors phenotype.

Omalizumab modulates bronchial reticular basement membrane thickness and eosinophil infiltration in severe persistent allergic asthma patients.

Severe persistent asthma causes a substantial morbidity and mortality burden and is frequently not well controlled, despite intensive guideline-based therapy. The unique monoclonal antibody approved for patients with severe allergic asthma is omalizumab: a recombinant humanised murine against IgE antibodies. The aim of the present study is to investigate the effect of long-term anti-IgE on the thickening of the reticular basement membrane (RBM) and eosinophil infiltration in bronchial biopsies from patients with severe persistent allergic asthma. Biopsies were obtained from 11 patients with severe persistent allergic asthma before and after (12 months) treatment with omalizumab. RBM thickness and eosinophils were measured by using light microscope image analysis. A significant mean reduction in RBM thickness and eosinophil infiltration were measured after one-year omalizumab treatment. No correlation between eosinophil reduction and RBM thickness reduction was found. No correlation between each of the previous two parameters and clinical parameters was detected. In conclusion, our study showed that a substantial proportion of severe asthmatics reduced the original bronchial RBM thickness and eosinophil infiltration after one-year treatment with anti-IgE, thus emphasizing the possible role of omalizumab in affecting airway remodeling in severe persistent allergic asthma.

Salbutamol: how does it enter smooth muscle cells?

Polyspecific organic cation transporters (OCTs) in human cell membranes are involved in the uptake, distribution and excretion of cationic compounds. Although their relevance to drug disposition in the liver, small intestine and kidney has been investigated previously, less is known about the influence of these transporters on the pharmacokinetics and pharmacodynamics of inhaled drugs. Drugs that are commonly administered by inhalation for the treatment of respiratory diseases, such as glucocorticoids and cationic ß(2)-agonists, might interact with several of these transporters, which are strongly expressed on the surfaces of airway epithelial cells. We evaluated the expression of OCT3 and measured the in vitro uptake of the short-acting ß(2)-agonist salbutamol (SALB), alone or in combination with corticosterone (CS) and beclomethasone dipropionate (BDP), by bronchial smooth muscle cells. Our results showed that these cells express the OCT3 transporter and that SALB enters the cell in a transporter-independent fashion. Moreover, CS and BDP have different activities on SALB transport inside the cell. CS increases SALB transport and BDP decreases SALB transport, although neither of these effects are statistically significant. A better understanding of these mechanisms might lead to the improved treatment of airway diseases.