Background: Platelets exhibit a unique lipid composition characterized by increased polyunsaturated fatty acids (PUFAs) and decreased saturated fatty acids (SFAs), distinguishing them from their progenitor cells. This specific SFA:PUFA ratio is critical for maintaining proper platelet function. In obesity, plasma lipid composition is altered—particularly due to increased dietary intake of SFAs—which has been associated with heightened platelet reactivity in response to subthreshold stimuli. Moreover, platelets from individuals with obesity are rapidly consumed, leading to accelerated production of highly reactive platelets that are often less responsive to antiplatelet therapy. We have previously shown that dietary SFAs can alter megakaryocyte function and proplatelet formation. Despite the established association between obesity and enhanced platelet reactivity, the mechanisms by which elevated SFAs influence platelet function remain poorly understood. Based on this, we hypothesize that a high-SFA diet will dose-dependently increase platelet reactivity.

Aim: To investigate the impact of different SFA ratios in high-fat diets on platelet function.

Results: We conducted an in vivo dose–response study in which mice were fed high-fat diets (60% total fat) enriched with increasing amounts of SFAs (20%, 50%, and 70%) for 12 weeks. As previously shown by our group, increasing the SFA content in high-fat diets led to weight gain and a reduction in platelet counts, with no significant changes in other blood cell populations.

Platelet function analysis by flow cytometry revealed that high SFA diets resulted in increased basal platelet activation. This was particularly evident in platelets from mice fed 70% SFA, which exhibited significantly elevated surface levels of integrin αIIbβ3 and P-selectin on resting platelets (p=0.03 and p=0.0004, respectively). Surface expression of glycoprotein VI (GPVI) and C-type lectin-like receptor 2 (CLEC-2) were also significantly higher in this group compared to the control and other high-fat diet groups (p<0.001). Additionally, platelets from mice fed 70% SFA diet showed enhanced P-selectin exposure following stimulation with CRP-A (1 µg/mL) and thrombin (0.5 U/mL). These findings were supported by increased ex vivo platelet aggregation in response to the same agonists. Furthermore, mice fed 50% and 70% SFA-enriched diets exhibited elevated levels of platelet–leukocyte aggregates in resting conditions, indicating heightened platelet activation in vivo.

To explore the mechanisms underlying increased platelet reactivity, we performed lipidomic analysis on platelets from each dietary group. The analysis revealed distinct lipid compositions among the groups, as demonstrated by clear separation in the partial least squares discriminant analysis (PLS-DA). LION pathway enrichment analysis identified increased levels of C14:0 and C12:0, along with enrichment in triacylglycerol and lipid storage pathways. Using MetaboAnalyst Pattern Search, we identified potential biomarkers such as elevated levels of PE (26:0_18:2), PC (O-36:4), and SM (t44:4)—all of which are components of the platelet membrane and are associated with increased membrane rigidity and curvature. To investigate the origin of these lipids, we compared lipid profiles from platelets, plasma, and megakaryocytes from these diets. The data revealed that while megakaryocytes primarily contributed structural lipids (phospholipids), plasma was the main source of energy-related lipids (triglycerides). This finding was further validated using Click-iT chemistry, confirming that platelets acquire lipids not only from megakaryocytes but also from plasma.

Conclusions: High dietary intake of SFAs alters platelet lipid composition and enhances platelet activation and aggregation. By linking dietary SFAs to increased platelet reactivity, this research offers critical insights into how different kinds of high-fat diets contribute to prothrombotic phenotypes, with important implications for developing dietary strategies to reduce cardiovascular risk in obesity.

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2025
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