Patients with Abdominal Aortic Aneurysm Demonstrate Higher Levels of Non-cholesterol Sterol Markers of Endogenous Cholesterol Synthesis

Aims: To establish the levels of selected non-cholesterol sterols in patients with abdominal aortic aneurysm (AAA) and to compare them with levels in non-AAA patients treated for lipid metabolism disorder. To compare the levels of high-sensitivity C-reactive protein (hs-CRP) and Lp-PLA 2 – inflammation markers in the same group of patients.

Study Design: A total of 58 AAA patients indicated for elective surgical procedure and 20 non-AAA patients in the control group treated for lipid metabolism disorder were examined.

Methodology: Lathosterol (Lat), desmosterol (Des), lanosterol (Lan), campesterol (Cam) and sitosterol (Sit) were analysed with the use of GC/MS in fasting plasma of patients with AAA and outpatients suffering from lipid metabolism disorder. hs-CRP and lipoprotein-associated phospholipase A2 were analysed in both groups.

Results: hs-CRP levels were significantly increased in patients with AAA compared to the control group (med. 3.6 mg/L, IQR 1.83 to 6.0 mg/L vs. 2.05 mg/L, IQR 0.99 to 3.0 mg/L, P = .007). Levels of non-cholesterol precursors of cholesterol synthesis – Lan, Des and Lat – were statistically significantly higher in the group of AAA patients compared to non-AAA patients (Lan: med. 0.28 µmol/L, IQR 0.24 to 0.32 µmol/L vs. 0.23 µmol/L, IQR 0.20 to 0.25 µmol/L, P = .004; Des: med. 3.69 µmol/L, IQR 3.12 to 4.66 µmol/L vs. 3.03 µmol/L, IQR 2.68 to 3.33 µmol/L, P = .0005; Lat: 5.95 µmol/L, IQR 5.18 to 6.9 µmol/L vs. 4.72 µmol/L, IQR 4.32 to 5.22 µmol/L, P = .0002) while there were no statistically significant differences in the absorption parameters of Sit or Cam in either group (Sit: med 6.29 µmol/L, IQR 5.02 to 9.37 µmol/L vs. 6.12 µmol/L, IQR 4.99 to 7.01 µmol/L, P = .65; Cam: med 8.6 µmol/L, IQR 7.31 to 10.71 µmol/L vs. 8.46 µmol/L, IQR 7.24 to 10.86 µmol/L, P = .96).

Conclusion: The markers of endogenous cholesterol synthesis in AAA patients are higher compared with those in non-AAA patients treated for lipid metabolism disorder. Higher hs-CRP levels in AAA patients show increased inflammatory activity compared with the control group.