Family history of hypertension-altered susceptibility of LDL to in vitro oxidation

Oxidative modification of low-density lipoprotein (LDL) increases its atherogenic potential to induce the accumulation of lipids and cells in the vascular wall. In order to study an association between hypertension and the susceptibility of LDL oxidation, 8 normotensive patients without family history of hypertension (NT), 5 normotensive patients with family history of hypertension (NT-FH), 6 hypertensive patients with (HT-FH) and 5 without family history of hypertension (HT) were evaluated. LDL was oxidatively modified by incubation with copper ions (1.6 μM). The course of LDL-oxidation was measured in vitro by continuous photometric monitoring of the diene formation through an increase in absorption at wavelength 234 nm at 37°C. Compared to NT, a shorter lag-phase (antioxidative capacity) in normotensive patients with family history was observed: NT 107±10 min vs NT/FH 87.5±11 min, p<0.07. The lag-phase in the hypertensive patients was: HT 50±14 min, HT-FH 47±4 min. A significant difference between NT and HT respectively HT-FH was recognized (p<0.005), conversely there was no significant difference between NT-FH and HT. These results indicate that 1. NT with family history of hypertension appear more susceptible to oxidative modification. 2. The antioxidative capacity in hypertensive patients is significantly lower compared to NT without family history of hypertension. Conclusions: Both normotensive patients with family history of hypertension and hypertensive patients may have an increased risk for vascular disease caused by an enhanced atherogenic potential of LDL.