Патогенетическое значение мембранных и метаболических нарушений при бронхитах у детей

Abstract

Study Objective: To study the features of intracellular and extracellular free-radical oxidation (FRO) processes with reference to the cellular membrane condition in various clinical forms of paediatric bronchitis. Study Design: prospective cohort study. Materials and Methods. The study included 237 children aged 2 to 15.5 years old with bronchitis. The patients were divided into three groups depending on the clinical form of bronchitis: acute bronchitis (AB) — 91 children (mean age: 9.8 years old); acute obstructive bronchitis (AOB) — 32 children (mean age: 7.5 years old); and recurrent bronchitis (RB) — 14 children (mean age: 10.2 years old). The control group included 43 conditionally healthy children (mean age: 9.5 years old). We conducted clinical examination, as well as standard instrumental and laboratory tests and interviewed all children. We studied FRO activity (using spontaneous and zymozan-induced luminol-depend chemicoluminescence, ICL), cumulative serum antioxidant activity (AOA), and ceruleoplasmin (CP). Red-cell membranes permeability by sodium was measured using determination of the maximum rate of Na+-Li+-exchange transport (ET) in RBC. Study Results. All patients demonstrated increased rate of Na+-Li+-ET, with the mean value in AB being 232 ± 7.0 (р < 0.05), in OAB — 269 ± 10.0 (р < 0.05), in RB — 328 ± 11.0 μmol Li (р < 0.01). In AB, ICL level was relatively constant vs. normal value irrespective of the disease phase (137.61 ± 22.3 counts/min/1,000 PMNL). In early OAB, ICL was significantly more active (up to 208.98 ± 7.6 counts/min/1,000 PMNL) which normalised later at clinical recovery. In patients with RB, peak ICL was as low as 107.06 ± 26.42 counts/min/1,000 PMNL; at clinical recovery, the value was even lower — 66.41 ± 8.9 counts/min/1,000 PMNL (р < 0.001 vs. healthy children). In acute phase of all forms of the disease, we recorded a significant raise in malondialdehyde; however, its peak concentration was seen in patients with RB; the value was significantly different not only from controls, but also from patients with AB and OAB; and at clinical stabilisation, the value reached 3.72 ± 0.08 μmol (р < 0.05). Patients with AB at recovery had the cumulative AOA of 39.9 ± 0.59% (р < 0.05); however, the control value was not achieved (42.39 ± 0.49%). CP levels were raised as well and reached 64.98 ± 0.43 mg%, but did not differ significantly from the initial value. In OAB, the cumulative OAO did not reach its peak value. Its mean value remained the same. In patients with RB, the cumulative AOA did not reach the normal value, but also reduced a lot (р < 0.05), together with reduced serum CP concentration from 60.20 ± 0.52 mg% to 57.83 ± 0.41 mg% (р < 0.05). Conclusion. Persistence and intensity of membrane and metabolic shifts in children with bronchitis are of great significance in the pathogenesis of a recurrent inflammation in bronchi and can be used as prediction criteria of the disease, allowing to set up a management plan. Keywords: children, bronchitis, free-radical oxidation of lipids, ion exchange system, antioxidant activity, ceruleoplasmin.