Effects of diets high in saturated fat and cholesterol on the lipid composition of canine platelets

Abstract

The phospholipid composition of platelets from dogs on various experimental diets was determined. Thyroidectomized foxhounds were fed a control diet or the control diet supplemented with (1) beef tallow, (2) beef tallow and cholesterol, or (3) beef tallow, cholesterol, and safflower oil for 23 weeks prior to isolation of platelets. Platelets from animals fed the control diet contained 36.7% phosphatidylcholine (PC), 22.8% phosphatidylethanolamine (PE), 18.4% sphingomyelin (Sph), 11.8% phosphatidylserine (PS), 6.3% phosphatidylinositol (PI), and 2.2% lysophosphatidylcholine. The PE was 77.6% in the plasmalogen form. No highly significant changes in the phospholipid class composition resulted from the experimental diets. Cholesterol supplementation of the diets, however, caused consistent alterations in the fatty acid compositions of the platelet phospholipids including increases in the percentages of 18:1 omega 9 (oleic acid), 18:2 omega 6 (linoleic acid), and 20:3 omega 6 (homo-gamma linolenic acid) and a decrease in the percentage of 20:4 omega 6 (arachidonic acid). Addition of safflower oil to the tallow-cholesterol diet partially reversed these effects. These cholesterol-induced alterations in fatty acid composition could be due to exchange with plasma lipids, de novo synthesis, or altered platelet metabolism. The mechanism remains to be determined.

Thromboxane B2 biosynthesis and phospholipids hydrolysis in platelets from hypercholesterolemic rabbits

“…Cholesteryl ester concentration in platelets from hypercholesterolemic rabbits (70 #g/mg protein) was much higher than control (8 #g/mg protein). A previous report suggested that the decreased arachidonic acid in platelets from canines fed a cholesterol diet was the result of use of arachidonic acid for cholesteryl ester synthesis (28). In our experiments, cholesterol esterification was promoted and cholesteryl esters were increased in platelets.…”

Influence of Plasma Lipid Composition on Activity of Factors V, VII and X in Single Comb White Leghorn and Fatty Liver Haemorrhagic Syndrome-Susceptible Laying Hens

“…When exposed to the outer platelet membrane, arachidonic acid is available to be used as a substrate for thromboxane synthesis leading to platelet aggregation (Pitas et al, 1979;Boberg et al, 1985). In our study, we found a positive correlation between arachidonic acid and FV activity.…”

A hereditary bleeding disorder of dogs caused by a lack of platelet procoagulant activity

“…In particular, the PS content of GSD platelets (11.1%) was nearly identical to that of control dogs (10.7%) and to a previously reported value of canine platelet PS content (11.8%). 43 …”