These findings indicate that dietary cholesterol, possibly in the form of modified plasma lipoproteins, is an important risk factor for the progression to hepatic inflammation in diet-induced NASH.

Assays measuring platelet aggregation (thrombus formation) at arterial shear rate mostly use collagen as only platelet-adhesive surface. Here we report a multi-surface and multi-parameter flow assay to characterize thrombus formation in whole blood from healthy subjects and patients with platelet function deficiencies. A systematic comparison is made of 52 adhesive surfaces with components activating the main platelet-adhesive receptors, and of eight output parameters reflecting distinct stages of thrombus formation. Three types of thrombus formation can be identified with a predicted hierarchy of the following receptors: glycoprotein (GP)VI, C-type lectin-like receptor-2 (CLEC-2)>GPIb>α6β1, αIIbβ3>α2β1>CD36, α5β1, αvβ3. Application with patient blood reveals distinct abnormalities in thrombus formation in patients with severe combined immune deficiency, Glanzmann’s thrombasthenia, Hermansky–Pudlak syndrome, May–Hegglin anomaly or grey platelet syndrome. We suggest this test may be useful for the diagnosis of patients with suspected bleeding disorders or a pro-thrombotic tendency.

CD40 ligand (CD40L), identified as a costimulatory molecule expressed on T cells, is also expressed and functional on platelets. We investigated the thrombotic and inflammatory contributions of platelet CD40L in atherosclerosis. Although CD40L-deficient (Cd40l ؊/؊ ) platelets exhibited impaired platelet aggregation and thrombus stability, the effects of platelet CD40L on inflammatory processes in atherosclerosis were more remarkable. Repeated injections of activated Cd40l ؊/؊ platelets into Apoe ؊/؊ mice strongly decreased both platelet and leukocyte adhesion to the endothelium and decreased plasma CCL2 levels compared with wildtype platelets. Moreover, Cd40l ؊/؊ platelets failed to form proinflammatory plateletleukocyte aggregates. Expression of CD40L on platelets was required for plateletinduced atherosclerosis as injection of Cd40l ؊/؊ platelets in contrast to Cd40l ؉/؉ platelets did not promote lesion formation. Remarkably, injection of Cd40l ؉/؉ , but not Cd40l ؊/؊ , platelets transiently decreased the amount of regulatory T cells

Background: Inactivation of integrin ␣ IIb ␤ 3 reverses platelet aggregate formation upon coagulation. Results and conclusion: Platelets from patient (Scott) and mouse (Capn1 Ϫ/Ϫ and Ppif Ϫ/Ϫ ) blood reveal a dual mechanism of ␣ IIb ␤ 3 inactivation: by calpain-2 cleavage of integrin-associated proteins and by cyclophilin D/TMEM16F-dependent phospholipid scrambling. Significance: These data provide novel insight into the switch mechanisms from aggregating to procoagulant platelets.

Custom-made and commercial parallel-plate flow chambers are widely used for studies of platelet activation and thrombus formation in whole blood at defined shear rates. When used in a reproducible way, such flow chamber devices give valuable information on the thrombogenic potential of human, mouse, or rat blood. This article aims to provide a practical guide for the use of parallel-plate flow chambers in combination with routine microscopic imaging techniques. The following methodological aspects are addressed: preparation of surface coatings, calculation of blood flow and shear rate, control of pre-analytical variables, protocols for routine performing of flow chamber tests with non-coagulating or coagulating blood, and procedures for real-time and end-point analysis of thrombus formation. Frequently encountered experimental problems and artifacts are discussed, as well as possibilities for using flow chamber devices as a diagnostic tool to test antithrombotic medication.