Erythrocyte membranes\' omega-3 fatty acids profile and its association with predictive equations applied in the estimation of cardiovascular risk

Introdução: Embora diversos mecanismos indiquem o papel cardioprotetor dos ácidos graxos ômega-3 (AG n-3), há controvérsias quanto seu impacto nos desfechos cardiovasculares. Nós hipotetizamos que os AG n-3 das membranas eritrocitárias refletem melhor o consumo e metabolização desses AG, permitindo identificar seus reais benefícios cardiovasculares. Objetivo: Associar os AG n-3 com biomarcadores cardiometabólicos e com o risco cardiovascular (RC) global. Métodos: Estudo transversal baseado no ensaio clínico CARDIONUTRI (n=356), com indivíduos de ambos os sexos (30-74 anos) e com pelo menos um dos seguintes fatores de risco: tabagismo, hipertensão, dislipidemia, diabetes mellitus ou obesidade. Foram analisados o lipidograma, subfrações de lipoproteínas, LDL(-), glicemia, HbA1c, insulina, HOMA-IR e biomarcadores de inflamação. Os AG dos eritrócitos foram analisados por meio de cromatografia gasosa. O RC global foi estimado pelos escores de Framingham (ERF), Reynolds (ERR) e da ACC/AHA 2013. Os resultados obtidos foram analisados no programa estatístico SPSS v.20.0 e Stata v.14.0. Resultados: Indivíduos com AG n-3 >6,24% e com razão n-6/n-3≤1,27 apresentaram menos colesterol não-HDL, Apo B, TG, LDL(-) e maior tamanho de LDL. O total de AG n-3 foi associado a menor RC estimado pelo ERF (OR=0,811; IC95%=0,675-0,976) e o padrão de membranas que contém mais n-6 e menos n-3 foi associado a maior risco (OR=1,469; IC95%=1,056-2,043). Perfil semelhante foi associado a maior RC estimado pelo ERR (OR: 1,276; IC95%=1,010-1,612), enquanto o padrão oposto, com mais n-3 e menos n-6, foi associado a menor RC (OR=0,747; IC95%=0,589-0,948). Não houve associações significativas com o RC estimado segundo o ACC/AHA 2013. Conclusão: Membranas eritrocitárias com mais AG n-3 e menos n-6 foram associadas a um perfil lipídico com menos lipoproteínas aterogênicas, menos TG e menor modificação da LDL. Esse perfil reduziu a chance de os indivíduos apresentarem RC moderado ou alto estimado pelos Escores de Risco de Reynolds e de Framingham. Introduction: Although several mechanisms confirm the cardioprotective role of omega-3 fatty acids (n-3 PUFA), there is still controversy regarding the impact on cardiovascular outcomes. We hypothesized that the erythrocytes membranes\' n-3 PUFA reflect better intake and metabolization of these fatty acids, allowing to identify their cardiovascular benefits. Objective: To evaluate the association of the n-3 PUFA with cardiometabolic biomarkers and absolute cardiovascular risk. Methods: A crosssectional study based on the CARDIONUTRI clinical trial (n = 356) with individuals of both sexes (30-74 years) with at least one of the following risk factors: smoking, hypertension, dyslipidemias, diabetes mellitus or obesity. We analyzed the lipid profile, lipoprotein subfractions, LDL(-), glycemia, HbA1c, insulin, HOMA-IR and inflammation biomarkers. Fatty acids were analyzed by gas chromatography. The 10- years projection of absolute cardiovascular risk was estimated by the Framingham (FRS), Reynolds (RRS) and ACC/AHA 2013 risk scores. The obtained results were analyzed by the statistical softwares SPSS v.20.0 and Stata v.14.0. Results: Individuals with n-3 PUFA > 6,24% and n-6/n-3 ≤ 1,27 had less plasma non-HDL cholesterol, Apo B, TG, LDL(-) and had bigger LDL size. Regarding FRS, the total n- 3 PUFA had association with lower cardiovascular risk (OR=0,811; IC95%=0,675- 0,976) and the membrane pattern containing more n-6 and less n-3 PUFA was associated with higher risk (OR=1,469; IC95%=1,056-2,043). Regarding RRS, the same pattern had association with higher risk (OR: 1,276; IC95%=1,010-1,612) whilst the opposite pattern, containing more n-3 and less n-6 PUFA, had association with lower risk (OR=0,747; IC95%=0,589-0,948). Associations with ACC/AHA 2013 were not significant. Conclusion: Erythrocyte membranes containing more n-3 and less n-6 PUFA were associated with a lipid profile characterized by less plasma atherogenic lipoproteins, less TG and fewer LDL modification. This membrane profile was associated with reduced chance to be classified as moderate or higher cardiovascular risk by the Reynolds and Framingham risk scores.