S. A. Syurin, MD, DrMedSci.

Kola Research Laboratory for Occupational Health, Kirovsk, Russia

Features of lipid peroxidation disorders in chronic bronchitis and chronic obstructive pulmonary disease

Introduction. The imbalance of the "lipid peroxidation - antioxidant protection" (POL-AOP) system is a critical link in the pathogenesis of both chronic bronchitis (CB) and chronic obstructive pulmonary disease (COPD) [1, 2]. However, the peculiarities of these two closely related but nosologically distinct respiratory diseases, cause interest in the study of corresponding disorders of lipid peroxidation processes.

The aim of the study was to examine the characteristics of LPO-AOD systems in CB and COPD.

Material and methods. The studies were performed in 91 CB patients and in 74 COPD patients in a phase of remission of the disease. Of the 165 people there were 89 men and 76 women. The average age of the examined patients was 45.7±1.2 and 46.9±1.4 years (p>0.5), and the average duration of the disease was 10.1±0.5 and 10.9±0.9 years (p>0.2), respectively. The reference group included 30 healthy individuals (16 men and 14 women) who did not differ significantly by sex, age and duration of the disease from the patients of the study group.

The state of LPO-AOD system was assessed by the following biochemical indices: the levels of total lipids (TL), diene conjugates (Dcon), diene ketones (Dket), malondialdehyde (MDA) in the serum, catalase (Cat) and peroxidase (Per) activity in erythrocytes, superoxide dismutase (SOD) activity in the serum, the level of sulfhydryl (SH) groups and ceruloplasmin (CP) in the serum, total antioxidant activity (TAA) of the serum. MicroSoft Excel 2007 was applied for statistical analysis of the collected data with determination of Student's t-criterion and Pearson’s correlation coefficient (r).

The results. Compared with healthy individuals the activation of free radical lipid oxidation was revealed both in patients with CB and COPD. It was more pronounced at the stage of primary products of lipid peroxidation, which was evidenced by increased levels of Dcon and Dket (p<0.05-0.001). It is important to note that the level of Dket in COPD was higher than in CB (p<0.05). The content of MDA (lipid peroxidation end product) was also higher in CB and COPD patients than in healthy subjects but to a lesser extent (p<0.05). Mean values of antioxidant protection indices in CB and COPD tended to decrease as compared to their levels in healthy individuals. Only the content of CP was higher than in healthy subjects (p<0.01-0.02). This finding can be attributed to a fact that CP combines properties of both antioxidant and acute phase protein that characterizes the residual activity of the lung inflammation in a phase of remission. In COPD, the content of CP was higher than in CB (p<0.05), indicating a higher activity of inflammation in the bronchopulmonary system in COPD patients (Table).

Table

Indices of LPO-AOD system in healthy individuals and CB and COPD patients (М±m)

Indices	Healthy individuals	CB patients	COPD patients
TL, g/l	6.40±0.20	7.38±0.22	7.28±0.20
Dcon, units оp/ml units op/mg TL	1.77±0.10 0.22±0.02	2.37±0.10* 0.36±0.02*	2.39±0.08* 0.37±0.02*
Dket, units оp/ml units op/mg TL	0.29±0.02 0.040±0.004	0.48±0.03* 0.064±0.003*	0.59±0.04*# 0.075±0.004*#
MDA, nM/ml nM/mg TL	208.5±16.2 31.1±2,0	262.4±10.4* 36.9±1.3*	276.9±10.1* 37.7±1.3*
Cat, mM/min.ml mM/min.10^6eryth	23.3±2.1 4.52±0.21	19.7±0.9 4.46±0.21	19.4±1.0 4.40±0.23
Per, l/min.ml l/min.10^6eryth	6.24±0.20 1.80±0.06	6.21±0.25 1.75±0.04	6.02±0.27 1.72±0.04
CP, g/l	251.7±9.8	274.6±6.0*	292.8±6.1*#
TAA, mMol/l	4.95±0.15	4.88±0.13	4.79±0.19
SOD, units	70.7±3.7	71.4±5.4	67.4±4.8
SH groups, mg %	2.19±0.06	2.12±0.11	2.06±0.12

Note.*- statistical significance (p<0.05) between healthy individuals and CB and COPD patients;

# - statistical significance (P<0.05) between CB and COPD patients.

According to correlation analysis in healthy persons there were seven pairs of correlating indicators: Dcon¾Dket, r = 0.71, p<0.01 Cat¾Per, r = 0.55, p<0,01; Per¾SH, r = 0.46, p<0.01; MDA¾Cat, r = 0.43, p<0.05; MDA¾SH, r = 0.39, p <0,05; MDA¾Per, r = 0.39, p<0,05; Dcon¾Cat, r = - 0.36, p<0,05. Four pairs of correlating indicators were found in CB patients: Dcon¾Dket, r = 0.49, p<0.01; Dcon¾MDA, r = 0.36, p<0.01; Per¾TAA, r = -0.35, p<0.01; Dcon¾Cat, r = -0.35, p<0.01.

Four pairs of correlating indices were also determined in COPD patients: Dcon¾Dket, r = 0.60, p<0.01; TAA¾ SH, r = 0.57, p<0.01; Dcon¾Cat, p<0.02; Per¾SOD, r = -0.36, p<0.05. The data obtained in healthy individuals showed highly associative and structural parameters of the LPO-AOD system, which provided an adequate balance of factors with the prooxidant and antioxidant activities. On the contrary, in CB and COPD there was a significant structural decrease in the LPO-AOD system and a pathological shift of the balance towards the activation of peroxidation processes.

Conclusion. These data indicate that activity of lipid peroxidation processes in patients with CB and COPD in a phase of remission remains substantially increased. The degree of this activation is somewhat more pronounced in patients with COPD compared with CB. However, the conducted study did not find out fundamental differences of LPO-AOD system disorders between the two compared diseases. This fact can serve as an argument in favor of the approval of the similarity in CB and COPD pathogenesis. The importance of lipid peroxidation processes in the pathogenesis of CB and COPD allows us to consider the degree of correction of LPO-AOD system status as a key criterion for the effectiveness of curative and rehabilitative measures.

References

1. Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global strategy for diagnosis, management, and prevention of chronic obstructive pulmonary disease. The 2009 report is available on: www.goldcopd.com.

2. Clinical recommendations. Pulmonology / Ed. AG Chuchalin. - M.: GEOTAR Media, 2007. – 225 p. (in Russian).