Lipolysis of emulsion models of triglyceride-rich lipoproteins is altered in male patients with abdominal aorta aneurysm

Abstract

Disorders of the lipid metabolism may play a role in the genesis of abdominal aorta aneurysm. The present study examined the intravascular catabolism of chylomicrons, the lipoproteins that carry the dietary lipids absorbed by the intestine in the circulation in patients with abdominal aorta aneurysm. Thirteen male patients (72 ± 5 years) with abdominal aorta aneurysm with normal plasma lipid profile and 13 healthy male control subjects (73 ± 5 years) participated in the study. The method of chylomicron-like emulsions was used to evaluate this metabolism. The emulsion labeled with 14 C-cholesteryl oleate and 3 H-triolein was injected intravenously in both groups. Blood samples were taken at regular intervals over 60 min to determine the decay curves. The fractional clearance rate (FCR) of the radioactive labels was calculated by compartmental analysis. The FCR of the emulsion with 3 H-triolein was smaller in the aortic aneurysm patients than in controls (0.025 ± 0.017 vs 0.039 ± 0.019 min -1 ; P < 0.05), but the FCR of 14 C-cholesteryl oleate of both groups did not differ. In conclusion, as indicated by the triglyceride FCR, chylomicron lipolysis is diminished in male patients with aortic aneurysm, whereas the remnant removal which is traced by the cholesteryl oleate FCR is not altered. The results suggest that defects in the chylomicron metabolism may represent a risk factor for development of abdominal aortic aneurysm. Key wordsAbdominal aorta aneurysms (AAA) are mostly of atherosclerotic origin (1) and the classical plasma lipid risk factors for coronary artery disease are involved. However, the metabolism of chylomicrons, lipoproteins that carry dietary fats absorbed by the intestine in the circulation, has not been investigated. Once in the bloodstream, chylomicron triglycerides are degraded by lipoprotein lipase and the resulting chylomicron remnants are then taken-up by the liver. Diminished chylomicron triglyceride breakdown and the accumulation of remnants are linked to coronary artery disease (2-5). However, evaluating this metabolism in human subjects is difficult. Plasma kinetic determi-

Metabolism of a Lipid Nanoemulsion Resembling Low-Density Lipoprotein in Patients with Grade III Obesity

“…In several studies from our group, a triglyceride-rich emulsion labeled with radioactive triglycerides and cholesteryl esters has been used to test the chylomicron metabolic pathway in several disorders that affect plasma lipid metabolism 13–19. This pathway is also common to very-low-density lipoproteins (VLDL) that (similarly to chylomicrons) undergo degradation of their triglyceride content by lipoprotein lipase using apo CII as a co-factor.…”

Efeitos da dieta vegetariana no metabolismo de quilomícrons e aspectos qualitativos da lipoproteína de alta densidade (HDL)

“…Permite a diferenciação entre quilomícrons e seus remanescentes, porém, apresenta a variável do período gasto para a absorção da gordura ingerida. (MARANHÃO et al, 1996;SPÓSITO et al, 2002;CHACRA et al, 2004), lúpus eritematoso sistêmico (BORBA et al, 2000), hipertensão arterial maligna (BERNARDES-SILVA et al, 1995) (HOSNI et al, 2007;CÉSAR et al, 2006;DE MARCHI et al, 2006 • Idade inferior a 20 anos e superior a 55 anos.…”

Metabolismo dos quilomícrons e capacidade da lipoproteína de alta densidade (HDL) de receber lípides na síndrome metabólica e no diabetes mellitus tipo 2

“…Zilversmith (ZILVERSMITH et al, 1979) e posteriormente por diversos pesquisadores MEYER et al, 1996;WEINTRAUB et al, 1996). Os resultados desses estudos mostram que essas lipoproteínas estão relacionadas com a incidência de DAC, com o seu desenvolvimento (PATSCH et al, 1992) e progressão (KARPE et al, 1994 (MARANHÃO et al, 1996), lúpus eritematoso sistêmico (BORBA et al, 2000), aneurisma de aorta (HOSNI et al, 2007), transplante cardíaco (VINAGRE et al, 2000), hipertensão arterial maligna (BERNARDES-SILVA et al, 1995).…”