Carbocysteine Modifies Circulating miR-21, IL-8, sRAGE, and fAGEs Levels in Mild Acute Exacerbated COPD Patients: A Pilot Study

Abstract

Patients with Chronic Obstructive Pulmonary Disease (COPD) periodically experience acute exacerbation (AECOPD). Carbocysteine represents a valid add on therapy in COPD by exerting antioxidant and anti-inflammatory activities. The in vivo effects of carbocysteine on inflammatory markers are not yet fully understood. The aims of this study were to assess: (i) miR-21, IL-8, soluble Receptor for Advanced Glycation End Products (sRAGE), and fluorescent Advanced Glycation End Products (fAGEs) in control subjects (n = 9), stable (n = 9), and AECOPD patients (n = 24); and (ii) whether carbocysteine modifies these markers and the functional parameters in mild AECOPD patients. Mild AECOPD patients received or not carbocysteine along with background inhalation therapy for 20 days. At the onset and at the end of the observation period, the following parameters were evaluated: FEV1, FEF25-75%, CAT questionnaire; miR-21 by Real Time PCR; IL-8 and sRAGE by ELISA; and fAGEs by spectro-fluorescence method. COPD patients showed higher levels of miR-21, IL-8, fAGEs and lower levels of sRAGE compared to that of controls. miR-21 inversely correlated with FEV1. IL-8 and fAGEs were significantly different in stable and exacerbated COPD patients. Carbocysteine improved symptoms, FEV1 and FEF25-75%, increased sRAGE, and reduced miR-21, IL-8, and fAGEs in mild AECOPD patients. The present study provides compelling evidence that carbocysteine may help to manage mild AECOPD by downregulating some parameters of systemic inflammation.

Keywords: COPD; antioxidants; carbocysteine; exacerbations; inflammation; respiratory pharmacology.

Figure 1

MiR-21, IL-8, soluble Advanced Glycation End Products (sRAGE), and fluorescent advanced glycation end products (fAGEs) expression in control, stable, and exacerbated COPD. Total RNA was purified from human serum, and miR-21 expression was assessed by real-time PCR. Results are expressed as 2^-delta CT (A). measurement of IL-8 and sRAGE in serum were determined by ELISA. Results are expressed as pg/mL (B,C). Measurement of fAGEs in serum was determined by fluorescence spectroscopy analysis. Results are expressed as Arbitrary Units (AU)/mg of total protein (D). Control n = 9, Stable COPD n = 9, Exacerbated COPD n = 24. * p < 0.05 Mann–Whitney test.

Figure 2

Evaluation of symptoms. Symptoms of mild AECOPD treated with or without (w/o) carbocysteine (Carbo) were evaluated by CAT at V1 (pretherapy) and at V2 (post-therapy). Mild AECOPD with Carbo n = 8, w/o Carbo n = 8. * p < 0.05 Wilcoxon test.

Figure 3

Evaluation of FEV1 and FEF25–75 in mild AECOPD before and post-therapy with or without carbocysteine. FEV1 and FEF25–75, were evaluated in mild AECOPD treated with or without (w/o) carbocysteine (Carbo) by spirometry at V1 (pretherapy) and at V2 (post-therapy). FEV1 and FEF25–75 were indicated in liter (FEV1 L) (A), (FEF25–75 L) (C) and in percentage (FEV1%) (B), (FEF25–75%) (D). Mild AECOPD with Carbo n = 8, w/o Carbo n = 8. * p < 0.05 Wilcoxon test.

Figure 4

MiR-21 and IL-8 levels in mild AECOPD before and post-therapy with or without carbocysteine. MiR-21 expression and IL-8 levels were evaluated in mild AECOPD treated with or without (w/o) carbocysteine (Carbo) at V1 (pretherapy) and at V2 (post-therapy) (A) Total RNA was purified from patient’s serum, and miR-21 expression was assessed by real-time PCR. Results are expressed as 2^-deltaCT. (B) Measurement of IL-8 in serum was determined by ELISA. Results are expressed as pg/mL. Mild AECOPD with Carbo n = 8, w/o Carbo n = 8. * p < 0.05 Mann–Whitney test.

Figure 5

sRAGE and fAGEs expression in mild exacerbated COPD before and post-therapy with or without carbocysteine. sRAGE and fAGE levels were evaluated in mild AECOPD treated with or without (w/o) carbocysteine (Carbo) at V1 (pretherapy) and at V2 (post-therapy). (A) Measurement of sRAGE in serum was determined by ELISA. Results are expressed as pg/mL. (B) Measurement of fAGEs in serum was determined by fluorescence spectroscopy analysis. Results are expressed as Arbitrary Units (AU)/mg of total protein. Mild AECOPD with Carbo n = 8, w/o Carbo n = 8. * p < 0.05 Mann–Whitney test.

Figure 6

Scheme of study design.