SARS-CoV-2 damages cardiomyocyte mitochondria and implicates long COVID-associated cardiovascular manifestations

Fig. 1. Spectrum of myocarditis in COVID-19 Patient #1. (A) ECG recordings retrieved from the AED, shows coarse ventricular fibrillation before the shock (blue frame). (B) CMR imaging of the patient, both T2-weighted sequences (T2WI) and short inversion time inversion recovery sequences (STIR) showed no myocardial edema in the mid short-axis slices. (C) A late enhancement was not observed in late gadolinium enhancement (LGE) sequences of the mid short-axis slices in the myocardium. Red arrowheads indicated suspected myocardial edema under the epicardium of the anterior wall (basal part), without significant delayed enhancement. (D) Masson's trichrome staining displayed interstitial collagen fiber deposits (red arrowheads). (E) HE analysis shows an abnormal structure in the myocardium. (F) Zoomed view, shows interstitial collagen fiber accumulation (red arrowheads), loss of integrity of myofibrillar bundles (blue arrowheads), and edema and necrosis of myofibrillar bundles (cyan arrowhead); Myofibrillar interstitial infiltration with inflammatory cells is also observed (green arrowheads). (G) Electron micrographs of the biopsy sample from the patient, showing local myofibrillar fibrosis…

Fig. 2. Spectrum of myocarditis in COVID-19 Patient #2. (A) Masson's trichrome staining. (B) Zoomed view displayed interstitial collagen fiber deposits (red arrowheads). (C) HE analysis shows an abnormal structure in the myocardium; (D) Zoomed view, shows interstitial collagen fiber accumulation (red arrowheads), loss of integrity of myofibrillar bundles (blue arrowheads), and myofibrillar interstitial infiltration with inflammatory cells is also observed (green arrowheads). (E) Electron micrographs of the biopsy sample from the patient, showing local myofibrillar fibrosis and proliferation of fibroblasts (red arrowheads); (F) Loss of integrity of myofibrillar bundles (blue arrowheads); (G) Necrosis of myofibrillar bundles (cyan arrowheads); (H) Lipofuscin granules in the cardiomyocytes (yellow frames); (I) and (J) A significant amount of vacuolations in the mitochondria (red stars). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 3. Mitochondria disorders in COVID-19 patient #3, #4, and #5. (A), (B), and (C) patient #3. (D), (E), and (F) patient #4. (G), (H), and (I), patient #5.

Fig. 4. Qualitative and quantitative analysis of mitochondria disorder in 2D images and 3D volumes. (A) Analysis of mitochondria disorder rate in 40 cardiomyocytes from each patient, each point represents an averaged percentile of disordered mitochondria from total 80 to 100 mitochondria in each cardiomyocyte. (B) and (C) 2D segmentation of outer membrane, inner membrane, and cristae in a healthy and disordered mitochondrion, respectively. (D) Analysis of mitochondria disorder by comparison the ratio of entire cristae length to the area of the mitochondrial cross section (LCRIS/AMITO). Healthy mitochondria like the one shown in Panel B have an averaged ratio around 29 μm−1 (open circles in top portion of Panel D). In contrast, disordered mitochondria like the one shown in Panel C have a lower ratio (filled circles in lower portion of Panel D). (E) Analysis of mitochondria disorder rate in 20 tissue blocks from each patient, each point represents an averaged percentile of disordered mitochondria from total 80 to 100 mitochondria in each block. (F) and (G) 3D segmentation of outer membrane, inner membrane, and cristae in a healthy and disordered mitochondrion, respectively. (H) Analysis of…

Fig. 5. Mitochondria disorganization in SARS-CoV-2 infected mice. (A) and (B) Electron micrographs of heart tissue from BA.5.2 and BQ.1 infected mice, showing similar disorder (red stars) in the mitochondria and myofibrillar bundles (blue and cyan arrowheads), as observed in the biopsy tissue from the patient. (C) Electron micrographs of heart tissue from control group, showing normal mitochondria ultrastructure. (D) Analysis of mitochondria disorder rate in 20 cardiomyocytes from each mouse, each point represents an averaged percentile of disordered mitochondria from total 80 to 100 mitochondria in each cardiomyocyte. (E) and (F) 2D segmentation of outer membrane, inner membrane, and cristae in a healthy and disordered mitochondrion, respectively. (G) Analysis of mitochondria disorder by comparison the ratio of entire cristae length to the area of the mitochondrial cross section (LCRIS/AMITO). Healthy mitochondria like the one shown in Panel E have an averaged ratio around 30 μm−1 (open circles in top portion of Panel G). In contrast, disordered mitochondria like the one shown in Panel F have a lower ratio (filled circles in lower portion of Panel G). (For interpretation of the…

Fig. 6. Proteomic profiling of SARS-CoV-2 infected mouse heart tissues. (A) and (C) Volcano plots representing differentially abundant proteins in BA.5.2 and BQ.1 infected mice heart tissue compared with mock group (n = 4). Green and blue dots represent proteins with a log2 fold change < −0.5 and a q value < 0.05. Plum and purple dots represent proteins with a log2 fold change > 0.5 and a q value < 0.05. Gray dot line indicates q value = 0.05. Only proteins with > 2 identified unique peptides were considered. (B) and (D) Numeric quantification of colored data points in A and C. (E) and (F) KEGG pathway enrichment analysis of significantly changed proteins. (G) Groups of proteins that upregulated or downregulated in BA.5.2 and BQ.1 infected mice heart, percent changes in protein level are indicated for each protein. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)