Abstract
Abstract only Physical fitness is associated with reduced risk factors for cardiovascular disease, in particular oxidized low‐density lipoprotein (ox‐LDL). Therefore determinants of ox‐LDL in fit individuals are important to understand. Antioxidant defenses and the concentration of low‐density lipoprotein (LDL) are associated with ox‐LDL concentration, however the relative importance of these variables is not fully understood. Paraoxonase 1 (PON1) is an antioxidant enzyme capable of preventing the oxidation of LDL. Moreover, total antioxidant capacity (TAC) is an assessment of the broad antioxidant status of the blood. PURPOSE Our purpose was to measure the association between ox‐LDL concentration and PON1 activity, TAC, and LDL concentration in highly trained individuals. METHODS Participants were instructed to refrain from exercise for 48 hours prior to blood sampling. Following a 12‐hour fast venous blood was taken at rest to determine ox‐LDL in plasma, PON1 in serum, and TAC in serum. LDL concentration was estimated using the Friedewald formula. Pearson Product Moment correlations were used to assess the relationships between ox‐LDL concentration and PON1 activity, ox‐LDL concentration and TAC, and ox‐LDL concentration and LDL concentration. RESULTS Fifteen individuals (12 males, 3 females) who had high cardiorespiratory fitness (VO 2max = 54.8 ± 1.7 ml×kg −1 ×min −1 ) completed the study. We found no association between ox‐LDL concentration and PON1 activity (r= 0.08, p = 0.78) and no association between ox‐LDL concentration and TAC (r= −0.15, p= 0.58). However there was a significant association between ox‐LDL concentration and LDL concentration (r= 0.82, p < 0.001). CONCLUSION This indicates that in highly trained individuals LDL concentration may be more important than antioxidant defenses in the development of circulating ox‐LDL concentration. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .