Platelet CD36 signaling generates H₂O₂. (A) HPLC chromatograms of 5 µM CBA or COH standards. (B) Representative HPLC chromatograms of COH accumulation by oxLDL-, LDL-, and PBS-treated platelets. (C) OxLDL in a concentration-dependent manner promotes H₂O₂ accumulation. Human platelets (6 × 10⁸/mL) were preloaded with 10 µM CBA followed by stimulation with 25, 50, or 100 µg/mL lipoprotein for 60 minutes. Platelets were lysed, and COH was extracted for HPLC analyses. (D) oxLDL/CD36 signaling synergistically promotes H₂O₂ generation by the GPVI pathway. Human platelets (6 × 10⁸/mL) were preloaded with 10 µM CBA followed by pretreatment with or without 50 µg/mL oxLDL for 60 minutes before further activation with 2 µM or 20 µM ADP, and/or 1 µg/mL or 10 µg/mL collagen-related peptide (CRP) for 15 minutes. Platelets were lysed, and COH was extracted for HPLC analyses. (E) oxLDL promotes H₂O₂ accumulation over time. Human platelets (6 × 10⁸/mL) were preloaded with 10 µM CBA followed by stimulation with PBS or 50 µg/mL oxLDL for up to 60 minutes. Platelets were lysed, and COH was extracted for HPLC analyses. CBA oxidation by oxLDL signaling is through CD36 and H₂O₂. Human platelets (6 × 10⁸/mL) were preloaded with 1000 U/mL denatured (“boiled”) PEG-catalase or functional PEG-catalase (PEG-Cat) (F) or pretreated with 1 µg/mL IgG or FA6-152 monoclonal antibody (FA6) (G) for 15 minutes, followed by 50 µg/mL oxLDL stimulation for 60 minutes. P values were determined by 1-way analysis of variance with Dunnett’s post hoc analysis (C,E,F), the paired Student t test (G), and 1-way analysis of variance with Tukey’s post hoc analysis (D). P = .66 for 25 µg/mL LDL vs PBS; P = .88 for 50 µg/mL LDL vs PBS (C); and P > .99 for 100 µg/mL LDL vs PBS. N ≥ 4 separate donors (C-D,F), and 3 separate donors (E,G). Data are expressed as mean ± SEM.