Vascular aging is a crucial risk factor for atherosclerotic ischemic stroke. Vascular aging is characterized by oxidative stress, endothelial dysfunction, inflammation, intimal and media thickening, as well as the gradual development of arterial stiffness, among other pathophysiological features. Regarding oxidative stress, increased concentration of reactive oxygen and nitrogen species is linked to atherosclerotic ischemic stroke in vascular aging. Additionally, oxidative stress is associated with an inflammatory response. Inflammation is related to aging through the “inflammaging” theory, which is characterized by decreased ability to cope with a variety of stressors, in combination with an increased pro-inflammatory state. Vascular aging is correlated with changes in cerebral arteries that are considered predictors of the risk for atherosclerotic ischemic stroke. The aim of the present review is to present the role of oxidative stress and inflammation in vascular aging, as well as their involvement in atherosclerotic ischemic stroke.

The omega-3 polyunsaturated fatty acids (PUFAs) Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) exert multiple cardioprotective effects, influencing inflammation, platelet activation, endothelial function and lipid metabolism, besides their well-established triglyceride lowering properties. It is not uncommon for omega-3 PUFAs to be prescribed for hypertriglyceridemia, alongside antiplatelet therapy in cardiovascular disease (CVD) patients. In this regard, we studied the effect of EPA and DHA, in combination with antiplatelet drugs, in platelet aggregation and P-selectin and α_IIbβ₃ membrane expression. The antiplatelet drugs aspirin and triflusal, inhibitors of cyclooxygenase-1 (COX-1); ticagrelor, an inhibitor of the receptor P2Y₁₂; vorapaxar, an inhibitor of the PAR-1 receptor, were combined with DHA or EPA and evaluated against in vitro platelet aggregation induced by agonists arachidonic acid (AA), adenosine diphosphate (ADP) and TRAP-6. We further investigated procaspase-activating compound 1 (PAC-1) binding and P-selectin membrane expression in platelets stimulated with ADP and TRAP-6. Both DHA and EPA displayed a dose-dependent inhibitory effect on platelet aggregation induced by AA, ADP and TRAP-6. In platelet aggregation induced by AA, DHA significantly improved acetylsalicylic acid (ASA) and triflusal’s inhibitory activity, while EPA enhanced the inhibitory effect of ASA. In combination with EPA, ASA and ticagrelor expressed an increased inhibitory effect towards ADP-induced platelet activation. Both fatty acids could not improve the inhibitory effect of vorapaxar on AA- and ADP-induced platelet aggregation. In the presence of EPA, all antiplatelet drugs displayed a stronger inhibitory effect towards TRAP-6-induced platelet activation. Both omega-3 PUFAs inhibited the membrane expression of α_IIbβ₃, though they had no effect on P-selectin expression induced by ADP or TRAP-6. The antiplatelet drugs exhibited heterogeneity regarding their effect on P-selectin and α_IIbβ₃ membrane expression, while both omega-3 PUFAs inhibited the membrane expression of α_IIbβ₃, though had no effect on P-selectin expression induced by ADP or TRAP-6. The combinatory effect of DHA and EPA with the antiplatelet drugs did not result in enhanced inhibitory activity compared to the sum of the individual effects of each component.

Background: Proprotein convertase subtilisin/kexin type 9 (PCSK9) promotes low-density lipoprotein receptor degradation and thereby regulates plasma LDL cholesterol levels. Although PCSK9 is primarily produced by the liver, it has been detected in platelets; however, the origin and functional relevance of platelet-associated PCSK9 remain unclear. Methods: Washed platelets (WPs) were isolated from normolipidemic subjects. Endogenous platelet PCSK9 content was quantified by ELISA, and PCSK9 molecular forms were assessed by immunoblotting. The WPs were incubated with recombinant PCSK9 (recPCSK9), and platelet aggregation in response to arachidonic acid (AA) or thrombin (Thr) was evaluated. The effects of LDL- or HDL-bound PCSK9 on platelet aggregation were also examined. Results: Platelets from normolipidemic subjects contained measurable amounts of PCSK9 (0.84 ± 0.27 ng/mg protein), which increased to 2.91 ± 0.53 ng/mg protein following incubation with recPCSK9. Exposure to recPCSK9 significantly enhanced AA- and Thr-induced platelet aggregation. In contrast, LDL and HDL inhibited platelet aggregation independently of their PCSK9 content. Conclusions: Human platelets contain endogenous PCSK9 and can accumulate additional PCSK9 from the extracellular environment. Exogenous PCSK9 enhances platelet aggregation, supporting a potential prothrombotic role for circulating PCSK9 even in normolipidemic individuals. These findings provide new insight into the complex interplay between PCSK9, lipoproteins, and platelet function.