OBJECTIVE: The identification of an atherogenic and a non-atherogenic lipoprotein profile, athero phenotype B vs. non-athero phenotype A, in a group of healthy normolipidemic subjects reveals a new clinical phenomenon in lipoprotein profiles, an atherogenic normolipidemia. Individuals with atherogenic normolipidemia are at increased risk to develop premature atherothrombosis and experience a sudden cardiovascular event.
METHODS: A quantitative analysis of non-atherogenic and atherogenic lipoproteins in plasma in a group of healthy normolipidemic volunteers who had no clinical signs of cardiovascular system impairment was performed. An innovative electrophoresis method on polyacrylamide gel (PAG) (Lipoprint LDL System, USA) was used for the analysis of plasma lipoproteins. With regard to lipids, total cholesterol and triglycerides in plasma were analyzed with an enzymatic method, CHOD PAP (Roche Diagnostics, FRG). Prostacyclin and thromboxane A2 were analyzed with an ELISA analysis (DRG USA). A new parameter, the score for anti-atherogenic risk (SAAR), was calculated as the ratio between non-atherogenic to atherogenic plasma lipoproteins in examined subjects.
RESULTS: There was a high concentration of LDL3-7 subfraction (p<0.0001) and a slowly increasing triglyceride concentration (p<0.05) in the atherogenic subgroup. The non-atherogenic subgroup of healthy subjects was characterized by high SAAR scores, as well as a low concentration of LDL3-7 subfractions (p<0.0001). Other statistically significant differences between the atherogenic and non-atherogenic subgroup, including total cholesterol, prostanoid parameters (prostacyklin, thromboxane A2), and lipoproteins values, were not confirmed.
CONCLUSIONS: The advantages of this new method include: (i) identification of an atherogenic and a nonatherogenic lipoprotein profile in an individual's plasma (ii) identification of an atherogenic normolipidemic lipoprotein profile in plasma (iii) introduction of a new risk measure, the score for anti-atherogenic risk (SAAR), for an estimation of a patient's atherogenic risk of atherothrombosis development. (iv) the presence of small dense LDL in plasma is decisive for declaration of an atherogenic lipoprotein profile. It is valid for hyperlipidemia and for normolipidemia as well.