ORIGINAL ARTICLES   

International Angiology 2000 December;19(4):331-6

Copyright © 2001 EDIZIONI MINERVA MEDICA

lingua: Inglese

The independent correlation of the impact of lipoprotein(a) levels and apolipoprotein E polymorphism on carotid artery intima thickness

Horejsí B., Spacil J., Ceska R., Vrablík M., Haas T., Horíneck A.

III Department of Internal Medicine of The Charles University Prague, Praha Czech Republic

Back­ground. Apo­lip­o­pro­tein E (apoE) plays a key role in lip­o­pro­tein metab­olism. It ­occurs in three iso­forms E2, E3 and E4. These iso­forms have dif­fer­ent ­impacts on plas­ma lip­o­pro­tein lev­els. The ­allele, or gene, cod­ing apoE4 is con­sid­ered a can­di­date for pre­ma­ture ath­ero­scler­o­sis devel­op­ment while the apoE2 gene is ­assumed to be pro­tec­tive. Lip­o­pro­tein(a) is also ather­o­gen­ic and its ­increased plas­ma con­cen­tra­tion is pre­sumed to be an inde­pen­dent risk fac­tor for pre­ma­ture ath­ero­scler­o­sis. Lip­o­pro­tein(a) is a pro­tein depos­it­ing direct­ly into the ath­e­rom­a­tous ­plaques, enhanc­ing cho­les­te­rol oxi­da­tion, com­pet­i­tive­ly inhib­it­ing plas­mi­no­gen for­ma­tion and thus hav­ing a pro­throm­bo­gen­ic ­effect. The aim of our study was to estab­lish a rela­tion­ship ­between com­mon carot­id ­artery inti­ma thick­ness and two inde­pen­dent risk fac­tors, apoE poly­mor­phism and ele­va­tion of plas­ma lip­o­pro­tein(a) lev­els.
Meth­ods. A cross-sec­tion­al study was per­formed on 114 ­patients who were ­referred to the lipid clin­ic for pri­mary hyper­li­pop­ro­tei­nae­mia. The ­patients ­received no treat­ment prior to exam­ina­tion. Plas­ma lev­els of total cho­les­te­rol, tri­gly­ce­rides, HDL-cho­les­te­rol, LDL-cho­les­te­rol, apoA, apoB, lip­o­pro­tein(a) and the apoE gen­o­type were deter­mined and the carot­id ­artery inti­ma thick­ness was meas­ured using ultra­so­nog­ra­phy.
­Results. The rel­a­tive fre­quen­cies of apoE2, E3 and E4 were 0.049, 0.830 and 0.121. The equal­ity of carot­id inti­ma thick­ness was test­ed using the Krusk­al-Wal­lis test. ­Medians of inti­ma thick­ness in a sub­group with the ­allele E2 were 0.72 mm, in a sub­group with the E3/E3 gen­o­type 0.70 mm and in a sub­group with the E4 ­allele 0.80 mm. The rela­tion­ship ­between carot­id inti­ma thick­ness and lip­o­pro­tein(a) lev­els was test­ed using ­Spearman’s cor­re­la­tion coef­fi­cient.
Con­clu­sions. No sta­tis­ti­cal­ly sig­nif­i­cant dif­fer­enc­es of carot­id inti­ma thick­ness among sub­groups divid­ed accord­ing to their apoE gen­o­type were found. No rela­tion­ship ­between carot­id inti­ma thick­ness and lip­o­pro­tein(a) lev­els was found. On the con­trary a close rela­tion­ship ­between carot­id inti­ma thick­ness and age and also some of the plas­ma lipid var­i­ables was record­ed using the meth­od of mul­ti­var­i­ate lin­e­ar regres­sion.