Fig. 1

Pathological analysis of the autopsied heart of a 38-year-old man with TGCV phenotype without PNPLA2 mutation. Panel a The transverse section of the autopsied heart stained with Masson’s trichrome showed circumferential patchy fibrosis of the left ventricular wall. The letters A, L, R, and P denotes anterior, left, right, and posterior, respectively. Panel b Lipid droplets (LDs) stained with oil red O in the cytoplasm of cardiomyocytes. Panel c Immunostaining for ATGL (Cell Signaling, Danvers, MA). Cardiomyocytes showed positive reactivity for ATGL. Panel d Coronary arteries with diffuse concentric-type stenosis. Panel e The transverse section of coronary artery was stained with Masson’s trichrome. Coronary artery revealed intimal thickening and fibroatheromatous lesions. Panel f Double-staining of Sudan black B and α-smooth muscle actin (Dako, Tokyo, Japan). Smooth muscle cells (brown color) with lipid droplet (blue color) distributed diffusely in the media and intima (arrows in Panel f). Asterisk represents the vascular lumen. Panel g TG (m/z 879.7) was identified as green and blue colors depending on the intensity. TG signals were diffusely detected in the arterial wall by imaging mass spectrometry. Green color denotes relatively higher intensity of TG than blue color. Myocardial and coronary TG contents (3.64 and 19.44 mg/g of tissue, respectively) were higher in this patient, compared with each of control group (1.4 ± 1.0, and 6.2 ± 4.8 mg/g of tissue, respectively). The detailed clinical profile of this patient is reported as Case 10 in the reference [29].

Scale bars: 1 cm in Panel a, 20 μm in Panel b and c, 5 mm in Panel d, 1 mm in Panel e, 20 μm in Panel f, 200 μm in Panel g