Extracellular vesicles do not contribute to higher circulating levels of soluble LRP1 in idiopathic dilated cardiomyopathy

Figure 1. Analysis of myocardial LRP1 α chain expression and localization. Representative confocal microscope images showing specific global detection of LRP1 α chain (red) (A) and more detailed localization of LRP1 α chain (green) in IsoB4—(grey) (B), CD31—(grey) (C and D) and vWF—(grey) (E) positive vessels. Cardiac muscle and cell nuclei are counterstained using an anti‐cTnI antibody (red) and DAPI (blue), respectively. Scale bars = 50 μm (F) Histogram represents quantification of LRP1 α chain positivity as percentage of arbitrary units per area. *P = 0.02.

Figure 2. Assessment of myocardial lipid content. Distribution of cholesteryl esters (CE), triglycerides (TG) and free cholesterol (FC) in both groups (St = standard, C = control and D = dilated cardiomyopathy). Histograms represent the quantification of total TG, CE and FC. n = 5 each control and idiopathic dilated cardiomyopathy (IDCM). *P = 0.026.

Figure 3. Increased levels of circulating sLRP1 in idiopathic dilated cardiomyopathy (IDCM) patients. The histogram represents quantification of circulating sLRP1 by ELISA. *P = 0.034. n = 15 control and n = 20 IDCM.

Figure 4. sLRP1 is not found in platelet‐free plasma‐derived extracellular vesicles (EV) fractions. (A) Representative analyses of platelet‐free plasma‐derived size‐exclusion chromatography (SEC) fractions by flow cytometry. Median fluorescence intensity (MFI) was measured, and the isotype negative control is represented as a dashed line. (B) Electron micrographs of vesicular protein‐enriched (8–10) and non‐enriched (11–13) fractions from a healthy control (left) and a idiopathic dilated cardiomyopathy (IDCM) patient (right) showing multifaceted assembly of round electron‐lucent membrane vesicles and a large quantity of smaller electron‐dense structures lacking a membrane bilayer, respectively. (C) Characteristic particle size distribution and concentration by NTA (healthy control, left; IDCM, right). n = 5 each control and IDCM. Scale bars = 100 nm.