Molecular magnetic resonance imaging of activated platelets allows noninvasive detection of early myocarditis in mice

Figures

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  Figure 1. (A) CD41 platelet immunohistochemistry of murine myocarditis 2 days after induction of myocarditis (× 20). Platelets were stained red. (B) Histological platelet count showed significant higher platelet numbers at early time points after induction of myocarditis compared to later time points. (C) Round golden LIBS-MPIOs bind to platelets in inflamed myocardium. They are highlighted with arrows. (D) Quantification of bound LIBS-MPIOs in the myocardium showed significant higher binding 2 days after induction of myocarditis compared to later time points. (E) Control antibody staining of murine myocarditis induced with CFA and porcine cardiac myosin (× 20). (F) CD41 immunohistochemistry of iCFA and myosin injected mice 2 days after injection. No relevant platelet accumulation was observed. (G) iCFA and myosin injected mice developed significantly less platelets accumulation in the myocardium at 2 days after injection compared to CFA and myosin injected mice. (H) Both control-MPIO injected myocarditis mice and LIBS-MPIO injected sham mice (iCFA + myosin) had significantly less MPIO accumulation in the myocardium compared to LIBS-MPIO injected myocarditis mice (CFA + myosin).

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  Figure 2. (A,B) CD41 immunohistochemistry of human inflammatory cardiomyopathy. The CD41 antigen is stained green. CD41 positive cells are highlighted with black arrows. (C) Control antibody staining of human inflammatory cardiomyopathy specimen. No CD41 positivity is seen (D) Human inflammatory cardiomyopathy specimen incubated with LIBS-MPIO. MPIOs can be identified as golden pellets. (E) Human inflammatory cardiomyopathy specimen incubated with control-MPIO. (F) Quantification of LIBS-MPIO binding to a human inflammatory cardiomyopathy specimen showed significantly more binding of LIBS-MPIO than control-MPIO.

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  Figure 3. Enlarged in-vivo 3D MRI 2 days after myocarditis induction with LIBS-MPIO injection. The first picture of each row shows the pre contrast agent scan. The second and third pictures show the scans 20 and 40 min after LIBS-MPIO injection. The given minute numbers below the post injection images refer to the end of the scan. Red arrows highlight focal signal voids after LIBS-MPIO injection in short axis, coronal and sagittal slices. (Drawings are provided by Servier Medical Art by Servier, licensed under Creative Commons Attribution 3.0 Unported License).

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  Figure 4. Enlarged in-vivo 3D MRI 2 days after induction of myocarditis with control-MPIO injection. The first picture of each row shows the pre-contrast agent scan. The second and third picture show scans 20 and 40 min after control-MPIO injection. The given minute numbers below the post injection images refer to the end of the scan. No relevant signal void visible after control-MPIO injection. (Drawings are provided by Servier Medical Art by Servier, licensed under Creative Commons Attribution 3.0 Unported License).

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  Figure 5. (A) Visualization of the signal quantification method. The signal in 20 periodically chosen slices of the myocardium was normalized to a 1% agarose reference probe and the pre-contrast agent scan. The reference probe is highlighted with a red arrow. (B) After injection of LIBS-MPIO a signal decrease was observed. The signal differed significantly from control-MPIO injected mice 20 and 40 min after injection. Animal numbers LIBS-MPIO: n = 12, control-MPIO: n = 9. (C) Visualization of the signal decrease in LIBS-MPIO injected mice (upper row) and control-MPIO injected mice (lower row). Blue indicates a lower signal in the myocardium compared to the pre contrast agent scan. (D) Histological counting of MPIOs in the myocardium showed significantly higher numbers of LIBS-MPIOs compared to control-MPIOs. (E) Platelet count was similar in both groups.