Inhibition of arterial thrombus formation by ApoA1 Milano
1Department of Medicine, University of Florida College of Medicine, the VA Medical Center, Gainesville, Florida32610, USA.
Abstract:
The mutant form of human apoA1, known as apoA1 Milano, is formed as a result of arginine 173 to cysteine substitution and inhibits experimental atherosclerosis in cholesterol-fed animals. This study was designed to determine if apoA1 Milano would modify arterial thrombogenesis. Sprague Dawley rats were intravenously administered the carrier alone (n=8) or apoA1 Milano (20 mg. kg-1. d-1 for 4 to 10 days, n=17). The abdominal cavity was opened, and the abdominal aorta was isolated. Whatman paper impregnated with 35% FeCl3 was wrapped around the surface of the aorta, and aortic flow was recorded continuously. In carrier-treated rats, an occlusive platelet-fibrin-rich thrombus was formed in 21.2+/-4.1 (mean+/-SD) minutes. Treatment of rats with apoA1 Milano markedly delayed time to thrombus formation (38.8+/-11.9 versus 21.2+/-4.1 minutes, P<0. 01), inhibited platelet aggregation (25+/-7% versus 50+/-11%, P<0. 01), and reduced weight of the thrombus (18.5+/-1.8 versus 23.7+/-2. 3 mg/cm, P<0.01). Total cholesterol and HDL levels remained similar in both groups of rats, but plasma apoA1 Milano levels were elevated in apoA1 Milano-treated rats. In in vitro studies, incubation of platelets with apoA1 Milano reduced ADP-induced platelet aggregation by about 50%, but apoA1 Milano had no direct effect on vasoreactivity. This study provides further evidence for critical role of platelets in thrombosis. Use of apoA1 Milano offers a novel approach to inhibit arterial thrombosis.
Insights
ApoA1 Milano, a mutant form of human apolipoprotein A1, significantly delays arterial thrombosis and inhibits platelet aggregation in rats. This finding suggests ApoA1 Milano as a novel therapeutic target for preventing blood clot formation.
Area of Science:
- Cardiovascular Science
- Hematology
- Biochemistry
Background:
- Apolipoprotein A1 (apoA1) plays a crucial role in lipid metabolism and reverse cholesterol transport.
- A mutant form, apoA1 Milano, has shown potential in inhibiting experimental atherosclerosis.
- The effect of apoA1 Milano on arterial thrombogenesis remains to be fully elucidated.
Purpose of the Study:
- To investigate the impact of apoA1 Milano on arterial thrombosis in a rat model.
- To determine if apoA1 Milano influences platelet aggregation and thrombus formation.
- To assess the potential of apoA1 Milano as an antithrombotic agent.
Main Methods:
- Sprague Dawley rats were treated with either a carrier or apoA1 Milano intravenously.
- Arterial thrombogenesis was induced using ferric chloride (FeCl3) on the abdominal aorta.
- Thrombus formation time, platelet aggregation, and thrombus weight were measured.
- In vitro platelet aggregation and vasoreactivity assays were performed.
Main Results:
- ApoA1 Milano significantly delayed thrombus formation time compared to the carrier group (38.8 vs. 21.2 minutes).
- Platelet aggregation was markedly inhibited (25% vs. 50%) and thrombus weight was reduced (18.5 vs. 23.7 mg/cm) in apoA1 Milano-treated rats.
- In vitro studies confirmed that apoA1 Milano inhibits ADP-induced platelet aggregation by approximately 50% without affecting vasoreactivity.
Conclusions:
- ApoA1 Milano demonstrates significant antithrombotic properties by delaying thrombus formation and inhibiting platelet aggregation.
- The study highlights the critical role of platelets in thrombosis.
- ApoA1 Milano represents a promising novel therapeutic strategy for inhibiting arterial thrombosis.
