The effect of elevated low-density lipoprotein cholesterol on surfactant proteins SP-A and SP-D content as a new mechanism of atherogenesis

Abstract

Aim of the study was to evaluate the effect of elevated level of low-density lipoprotein cholesterol (LDL-C) on surfactant protein SP-A and SP-D content in blood, as a new factor of atherogenesis, in men and women in Novosibirsk.Materials and methods. The study included 174 people (87 men and 87 women), residents of Novosibirsk, aged 45 to 69 years. An anthropometric examination, measurement of blood pressure, determination of the lipid spectrum, blood glucose and surfactant proteins SP-A and SP-D content (enzyme immunoassay).Results. According to the results of the examination, 82 examined persons (47.1 %) were included in the group with LDL-C content > 3.0 mmol/l(main group), 92 – in the group with LDL-C content ≤ 3.0 mmol/l (comparison group) (52.9 %). The value of high SP-A and SP-D content (upper quartile) was determined, which amounted to ≥ 1413 pg/ml SP-A in men and ≥ 1649 pg/ml in women, and ≥ 1772 ng/ml SP-D in men and ≥ 1626 ng/ml in women. It was found that in the main group, the body weight of the examined persons was lower than in the comparison group, and high SP-A level was more common (p = 0.033). In the total sample a direct association of upper quartile SP-A level with LDL-C content > 3.0 mmol/l was revealed (p = 0.021). Using multivariate analysis, it was found that LDL-C concentration > 3.0 mmol/l is an independent factor that directly affects the dependent variable the presence of high SP-A level in general totality of examined individuals (odds ratio 2.20, 95 % confidence interval 1.05–4.62, p = 0.036).Conclusions. In men and women of Novosibirsk, aged 45–69 years, high blood SP-A level (≥ 1413 pg/ml in men and ≥ 1649 pg/ml in women) occurs more often at LDL-C content > 3.0 mmol/l than at LDL-C level ≤ 3.0 mmol/l. In the total sample of the examined persons, a direct association of high SP-A with LDL-C content > 3.0 mmol/l was revealed, and using multivariate analysis it was found that LDL-C concentration > 3.0 mmol/l directly affects the presence of high blood SP-A level and increases the probability of this event by 2.2 times.