title: Cholesterol-induced stimulation of platelet aggregation is prevented by a hempseed-enriched diet.
abstract: Hypercholesterolemia indirectly increases the risk for myocardial infarction by enhancing the ability of platelets to aggregate. Diets enriched with polyunsaturated fatty acids (PUFAs) have been shown to reduce the detrimental effects of cholesterol on platelet aggregation. This study investigated whether dietary hempseed, a rich source of PUFAs, inhibits platelet aggregation under normal and hypercholesterolemic conditions. Male New Zealand white rabbits were fed one of 6 dietary interventions: regular control diet (RG); control diet + 10% hempseed (HP); control diet + 10% partially delipidated hempseed (DHP); control diet + 0.5% cholesterol (OL); control diet + 0.5% cholesterol + 10% hempseed (OLHP); control diet + 5% coconut oil (CO). After 8 weeks, blood was collected to measure ADP- and collagen-induced platelet aggregation and plasma levels of fatty acids, cholesterol, and triglycerides. The hempseed-fed animals (HP and OLHP) displayed elevated plasma levels of PUFAs and a prominent enhancement in 18:3n-6 (gamma-linolenic acid, GLA) levels, a unique PUFA found in hempseed. The cholesterol-supplemented groups (OL and OLHP) had significantly elevated plasma levels of cholesterol and triglycerides, but platelet aggregation was significantly augmented only in the OL group. The addition of hempseed to this diet (OLHP) normalized aggregation. The direct addition of GLA to the OL platelet samples blocked the cholesterol-induced stimulation of platelet aggregation. The results of this study demonstrate that when hempseed is added to a cholesterol-enriched diet, cholesterol-induced platelet aggregation returns to control levels. This normalization is not due to a reduction in plasma cholesterol levels, but may be partly due to increased levels of plasma GLA.
authors.affiliation: Canadian Centre for Agri-food Research in Health and Medicine, St. Boniface Hospital Research Centre, and Department of Physiology, Faculty of Medicine, University of Manitoba, MB R2H2A6, Canada.
authors.forename: M A
authors.initials: MA
authors.lastname: Prociuk
authors.forename: A L
authors.initials: AL
authors.lastname: Edel
authors.forename: M N
authors.initials: MN
authors.lastname: Richard
authors.forename: N T
authors.initials: NT
authors.lastname: Gavel
authors.forename: B P
authors.initials: BP
authors.lastname: Ander
authors.forename: C M C
authors.initials: CM
authors.lastname: Dupasquier
authors.forename: G N
authors.initials: GN
authors.lastname: Pierce
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D001835:Body Weight; D002188:Cannabis / Q000737:chemistry; D002788:Cholesterol Esters / Q000097:blood; D002791:Cholesterol, Dietary / Q000008:administration & dosage / Q000097:blood; D019587:Dietary Supplements; D004195:Disease Models, Animal; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage / Q000032:analysis / Q000097:blood / Q000494:pharmacology*; D006937:Hypercholesterolemia / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000032:analysis / Q000097:blood / Q000494:pharmacology*; D011817:Rabbits; D012639:Seeds; D014280:Triglycerides / Q000097:blood; D017965:gamma-Linolenic Acid / Q000494:pharmacology
chemical_list: D002788:Cholesterol Esters; D002791:Cholesterol, Dietary; D005231:Fatty Acids, Unsaturated; D010975:Platelet Aggregation Inhibitors; D014280:Triglycerides; D017965:gamma-Linolenic Acid