triolein and Aortic-Aneurysm--Abdominal

Abdominal aortic aneurysm (AAA) is a vascular disease involving gradual dilation of the abdominal aorta and high rupture-related mortality rates. AAA is histologically characterized by oxidative stress, chronic inflammation, and extracellular matrix degradation in the vascular wall. We previously demonstrated that aortic hypoperfusion could cause the vascular inflammation and AAA formation. However, the preventive method for hypoperfusion-induced AAA remains unknown. In this study, we evaluated the effect of fish oil on AAA development using a hypoperfusion-induced AAA animal model. Dilation of the abdominal aorta in the fish oil administration group was smaller than in the control group. Collagen destruction and oxidative stress were suppressed in the fish oil administration group than in the control group. These results suggested that fish oil could prevent the development of AAA induced by hypoperfusion.

Topics: Animals; Aorta, Abdominal; Aortic Aneurysm, Abdominal; Collagen; Dietary Supplements; Disease Models, Animal; Endothelium, Vascular; Fish Oils; Male; Oxidative Stress; Perfusion; Proteolysis; Rats; Rats, Sprague-Dawley; Triolein

Abdominal aortic aneurysm (AAA) is a vascular disease involving the gradual dilation of the abdominal aorta. It has been reported that development of AAA is associated with inflammation of the vascular wall; however, the mechanism of AAA rupture is not fully understood. In this study, we investigated the mechanism underlying AAA rupture using a hypoperfusion-induced animal model. We found that the administration of triolein increased the AAA rupture rate in the animal model and that the number of adipocytes was increased in ruptured vascular walls compared to non-ruptured walls. In the ruptured group, macrophage infiltration and the protein levels of matrix metalloproteinases 2 and 9 were increased in the areas around adipocytes, while collagen-positive areas were decreased in the areas with adipocytes compared to those without adipocytes. The administration of fish oil, which suppresses adipocyte hypertrophy, decreased the number and size of adipocytes, as well as decreased the risk of AAA rupture ratio by 0.23 compared to the triolein administered group. In human AAA samples, the amount of triglyceride in the adventitia was correlated with the diameter of the AAA. These results suggest that AAA rupture is related to the abnormal appearance of adipocytes in the vascular wall.

Topics: Adipocytes; Aged; Aged, 80 and over; Animals; Aortic Aneurysm, Abdominal; Collagen; Endothelium, Vascular; Fish Oils; Humans; Hypertrophy; Macrophages; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Middle Aged; Rats; Rats, Sprague-Dawley; Triolein

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 14C-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 14C-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.

Topics: Aged; Aortic Aneurysm, Abdominal; Body Mass Index; Carbon Radioisotopes; Case-Control Studies; Cholesterol Esters; Chylomicrons; Emulsions; Humans; Injections, Intravenous; Lipolysis; Male; Metabolic Clearance Rate; Triolein