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The functional role of platelets is intricately linked to the dynamic organization of two main components of the cytoskeleton, microtubules and actin fibers. Throughout the phases of platelet activation, spreading, and retraction, both of these essential polymers undergo continuous and orchestrated reorganization. Our investigation of the dynamic cytoskeletal changes during these phases highlights a sequential remodeling of the actin cytoskeleton in adherent platelets from the formation of initial actin nodules through the development of stress fibers and a subsequent return to nodular structures. Concurrently, the marginal ring of microtubules, characteristic of resting platelets, undergoes a re-organization induced by marginal band extension and coiling toward the formation of star-like bundles of microtubules. Subsequently, these bundles are dispersed into individual microtubules, which are re-bundled at later stages before ring-like structures are formed again. These findings suggest a compelling tendency for both cytoskeletal components to revert to their original configurations. Notably, the early steps of platelet cytoskeleton reorganizations have previously been shown to be regulated by the signaling cascade triggered during platelet activation, which leads to an increase of cytosolic calcium concentrations. We show here that later steps are potentially regulated by a progressive decrease of intracellular calcium concentrations as platelets approach the end of their functional lifespan.

Background The percentage of women

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The functional role of platelets is intricately linked to the dynamic organization of two main components of the cytoskeleton, microtubules and actin fibers. Throughout the phases of platelet activation, spreading, and retraction, both of these essential polymers undergo continuous and orchestrated reorganization. Our investigation of the dynamic cytoskeletal changes during these phases highlights a sequential remodeling of the actin cytoskeleton in adherent platelets from the formation of initial actin nodules through the development of stress fibers and a subsequent return to nodular structures. Concurrently, the marginal ring of microtubules, characteristic of resting platelets, undergoes a re-organization induced by marginal band extension and coiling toward the formation of star-like bundles of microtubules. Subsequently, these bundles are dispersed into individual microtubules, which are re-bundled at later stages before ring-like structures are formed again. These findings suggest a compelling tendency for both cytoskeletal components to revert to their original configurations. Notably, the early steps of platelet cytoskeleton reorganizations have previously been shown to be regulated by the signaling cascade triggered during platelet activation, which leads to an increase of cytosolic calcium concentrations. We show here that later steps are potentially regulated by a progressive decrease of intracellular calcium concentrations as platelets approach the end of their functional lifespan.

Background: The percentage of women <50 years of age hospitalized with myocardial infarction is increasing. We describe the clinical, morphological, and biological characteristics, as well as the clinical outcomes of this population., Methods and Results: This prospective, observational study included consecutive women <50 years of age admitted for myocardial infarction at 30 centers in France (May 2017-June 2019). The primary outcome was the composite of net adverse clinical events: all-cause death, cardiovascular death, recurrent myocardial infarction, stent thrombosis, any stroke, or major bleeding occurring during hospitalization with a 12-month follow up. Three hundred fourteen women were included. The mean age was 43.0 (±5.7) years, 60.8% presented with ST-segment-elevation myocardial infarction, 75.5% were current smokers, 31.2% had a history of complicated pregnancy, and 55.1% reported recent emotional stress. Most (91.6%) women presented with typical chest pain. Of patients on an estrogen-containing contraceptive, 86.0% had at least 1 contraindication. Of patients with ST-segment-elevation myocardial infarction, 17.8% had myocardial infarction with nonobstructive coronary arteries and 14.6% had spontaneous coronary artery dissection, whereas 29.3% presented with multivessel vessel disease. During hospitalization, 11 net adverse clinical events occurred in 9 (2.8%) women, but no deaths or stent thromboses occurred. By 12 months, 14 net adverse clinical events occurred in 10 (3.2%) women; 2 (0.6%) died (from progressive cancer) and 25 (7.9%) had an ischemia-driven repeat percutaneous coronary intervention., Conclusions: Most young women with myocardial infarction reported typical chest pain and had modifiable cardiovascular risk factors. History of adverse pregnancy outcomes and prescription of combined oral contraceptive despite a contraindication were prevalent, emphasizing the need for comprehensive cardiological and gynecological evaluation and follow-up., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03073447.