Systemic biomarkers of oxidative and inflammatory alterations in chronic obstructive pulmonary disease

Kronična opstrukcijska plućna bolest (KOPB) je složeni poremećaj koji zahvaća pluća, ali i sistemski odjeljak. Naše se istraživanje temeljilo na hipotezi da je u bolesnika s KOPB-om prisutna sistemska upala i sistemski oksidacijski stres. Sukladno tome, cilj ovog istraživanja bio je istražiti sistemske pokazatelje oksidacijskih i upalnih promjena u bolesnika sa stabilnim KOPB-om te ispitati povezanost sistemskih antioksidansa s poremećajem funkcije pluća i biljezima sistemske upale. Ispitali smo i dijagnostičku učinkovitost biljega sistemskog oksidacijskog stresa u razlikovanju zdravih i oboljelih od KOPB-a. Sistemski biljezi oksidacijskog stresa (albumin, transferin, ceruloplazmin, ukupni bilirubin, slobodne tiolne skupine, malondialdehid (MDA), paraoksonazna i arilesterazna aktivnost paraoksonaze 1 (PON1), te ekspresija i aktivacija unutarstaničnih signalnih molekula Hsp27, Hsp70, ERK, JNK i p38) određeni su u 106 bolesnika sa stabilnim KOPB-om i 45 zdravih ispitanika. Ispitane su i njihove povezanosti s biljezima sistemske upale (CRP, fibrinogen, ukupni leukociti), pušenjem i pokazateljima funkcije pluća (FEV1 i FEV1/FVC). Bolesnici s KOPB-om su imali povišene koncentracije ceruloplazmina i MDA, snižene koncentracije albumina, transferina i tiola, te snižene obje ispitane aktivnosti PON1. Koncentracije ukupnog bilirubina nisu se razlikovale usporedbom ispitivanih skupina. Ceruloplazmin je pokazao pozitivnu korelaciju s CRP-om i fibrinogenom. Albumin i transferin su pokazali negativnu korelaciju s CRP-om, te pozitivnu korelaciju sa slobodnim tiolima. Transferin je negativno korelirao s fibrinogenom. Jedini pokazatelj povezan s funkcijom pluća bio je MDA. Usporedbom pušača, bivših pušača i nepušača iz skupine bolesnika s KOPB-om nisu nađene razlike u koncentracijama promatranih biljega oksidacijskog stresa i upale. Povišene koncentracije ceruloplazmina su najsnažniji prediktor prisutnosti KOPB-a. Model koji uključuje ceruloplazmin, albumin, MDA i arilesteraznu aktivnost PON1 te biljege sistemske upale pokazao je najbolju dijagnostičku učinkovitost u predviđanju KOPB-a (AUC (95%CI) = 0,96 (0,92 – 0,99)). Predloženi bi model mogao ispravno predvidjeti prisutnost KOPB-a u 89% bolesnika. Također, naši su rezultati ukazali da je razina ekspresije Hsp27 i Hsp70 u leukocitima periferne bila je najniža u pušača s KOPBom. Ekspresija svih ispitivanih MAPK (ERK, JNK i p38) u perifernim leukocitima bolesnika s KOPB-om nije se razlikovala u usporedbi sa zdravim ispitanicima. Aktivacija ERK bila je značajnija kod zdravih i bolesnih nepušača, dok je aktivacija JNK i p38 bila najizraženija u pušača s KOPB-om. Rezultati su ukazali da prisutnost bolesti i pušenje utječu na ispitane unutarstanične signalne molekule. Bolje razumijevanje ovih molekularnih mehanizama moglo bi pomoći u dijagnozi i pronalaženju novih terapijskih meta za KOPB. Dijagnostičke karakteristike predloženog modela koji kombinira koncentracije biljega sistemske upale i sistemskog oksidacijskog stresa ukazuju da bi se on mogao koristiti kao vrijedan alat u razlikovanju zdravih ispitanika i bolesnika s KOPB-om.Background: Chronic obstructive pulmonary disease (COPD) is a complex disorder affecting the lungs and the systemic compartment. We hypothesized that systemic inflammation and systemic oxidative stress are present in patients with COPD. Therefore, we aimed to investigate markers of systemic oxidative and inflammatory alterations in patients with stable COPD, and to test the association of systemic antioxidants with indicators of lung function and systemic inflammation. The diagnostic accuracy of systemic oxidative stress parameters in distinguishing between healthy subjects and patients with COPD was also evaluated. Materials and methods: Systemic oxidative stress markers (albumin, transferrin, ceruloplasmin, total bilirubin, thiols, malondialdehyde (MDA), paraoxonase and arylesterase activity of paraoxonase 1 (PON1), and the expression and activation of intracellular signalling molecules Hsp27, Hsp70, ERK, JNK i p38) were assessed in 106 stable COPD patients and 45 healthy subjects. Their association with systemic inflammatory markers (CRP, fibrinogen, total leukocytes), smoking status and lung function parameters (FEV1 i FEV1/FVC) was investigated. Results: Higher ceruloplasmin and MDA concentrations, and lower albumin, transferrin, thiols and PON1 activities (paraoxonase and arylesterase) were found in patients with COPD. Total bilirubin concentrations were similar in the studied groups. Ceruloplasmin showed a positive correlation with CRP and fibrinogen. Albumin and transferrin showed a negative correlation with CRP, and a positive corelation with thiols. Transferrin negatively correlated with fibrinogen. Only MDA showed an association with pulmonary function. No differences were found comparing concentrations of oxidative stress and inflammatory markers between COPD patients subdivided according to their smoking status. Ceruloplasmin was the strongest single predictor of COPD. The model combining ceruloplasmin, albumin, MDA, arylesterase PON1 activity, and markers of systemic inflammation demonstrated very good diagnostic performances (AUC (95%CI) = 0,96 (0,92 – 0,99)). The proposed model correctly identifies 89% of patients with COPD. In addition, our results showed that the decrease in expression of peripheral blood leukocytes' Hsp27 and Hsp70 was the most prominent in COPD smokers. Expression levels of all three MAPKs investigated was not altered in leukocytes of COPD patients compared to healthy subjects. However, ERK activation was stimulated in healthy and COPD non-smokers, while JNK and p38 activation was the most pronounced in COPD smokers. Conclusions: Our results showed that COPD and smoking affect the intracellular signalling pathways investigated. Improved understanding of these molecular mechanisms could help identify novel targets for diagnosis and therapeutic interventions in COPD. Diagnostic characteristics of the proposed model, obtained by combining markers of systemic inflammation and systemic oxidative stress, suggest its potential value as an additional tool in COPD diagnosis