March 1, 1983
View Full PaperArachidonic acid metabolism by platelets of differing size
Key Result
The absolute ability of platelets to incorporate arachidonic acid, convert it to active metabolites, and release them is proportional to their mean platelet volume.
Structured PICO
Does mean platelet volume affect arachidonic acid metabolism and thromboxane B2 release in human platelets?
P
Population
Human platelets fractionated into size-dependent subpopulations by counterflow centrifugation
E
Exposure
Thrombin and collagen stimulation
C
Comparator
Comparison across different mean platelet volumes (MPV)
O
Outcome
Incorporation and metabolism of tritiated arachidonic acid ([3H]AA) and release of thromboxane B2 (TXB2)surrogate
Larger platelets have a greater absolute capacity to incorporate and metabolize arachidonic acid into active metabolites like thromboxane B2, providing a mechanistic basis for their increased reactivity.
Abstract
The relationship between mean platelet volume (MPV) and platelet arachidonic acid metabolism was examined by studying the ability of human platelets of different size to incorporate and metabolize tritiated arachidonic acid (3HAA). Platelet phospholipids were labelled with 3HAA and the platelets were then fractionated into size-dependent subpopulations by counterflow centrifugation. The incorporation of 3HAA increased through the fractions proportional to the MPV. After thrombin stimulation the per cent of total 3H-radioactivity released from the platelets decreased as the MPV increased. However, fractionation of the released 3H-radioactivity by HPLC (high performance liquid chromatography) demonstrated that MPV had no significant influence on the per cent of total platelet 3H-radioactivity released as cyclooxygenase products or as HETE (12-hydroxyeicosatetraenoic acid) but that the release of unmetabolized 3HAA decreased as MPV increased. In separate experiments using unlabelled platelets the absolute release of thromboxane B2 (TXB2) after collagen- and thrombin-induced aggregation was measured by radioimmunoassay and was found to increase in proportion to the MPV. These results demonstrate that the release of arachidonic acid metabolites is qualitatively similar in platelets of different size. However, the absolute ability of platelets to incorporate arachidonic acid, convert it to active metabolites and release them is proportional to their volume. The ability of platelets to release unmetabolized arachidonic acid varies inversely with their MPV.
Cite This Study
Jakubowski et al. (Tue,) reported a other. Mean platelet volume (MPV) vs. Platelets of differing sizes was evaluated on Arachidonic acid incorporation and metabolism. The absolute ability of platelets to incorporate arachidonic acid, convert it to active metabolites, and release them is proportional to their mean platelet volume.