Non-neuronal components of cholinergic system in peripheral blood T-cells of COPD patients

Although the main causes of systemic inflammation in COPD remain to be elucidated, circulating cells are strongly involved in the pathogenesis of COPD. Non-neuronal components of cholinergic system may participate in the airway inflammation of COPD despite their role in the systemic compartment remains not fully elucidated. We evaluated: 1) the muscarinic M1, M2, M3 receptors and Choline-AcetylTransferase (ChAT) expression, the ACh-binding, and the cell apoptosis (on the basis of annexin V binding) in peripheral blood T cells (PBTs) from COPD patients, control smokers and controls using flow-cytometry; 2) the serum levels of ACh in the same groups of subjects; 3) the effects of Tiotropium (Spiriva®), alone or in combination with Fluticasone Propionate and Salmeterol, on the PBTs apoptosis in COPD patients. We showed that: 1) M1, M2, M3 and ChAT expression as well as the ACh binding and the levels of serum ACh are increased in Smokers and COPD patients when compared to controls; 2) T-cell apoptosis (CD8+) is increased in Smokers and COPD patients when compared to controls; 3) Fluticasone Proprionate (FP) increases PBTs apoptosis and the combination of FP and Tiotropium further increases it. This study suggests that the altered expression of the non-neuronal components of cholinergic system in circulating PBTs might contribute to their apoptosis. Further studies are necessary to assess the clinical significance of this event.