Non-linear optical microscopy sheds light on cardiovascular disease

Area of Science:

• Cardiovascular Biology
• Biomedical Imaging
• Optical Microscopy

Background:

• Cardiac diseases often involve increased fibrosis and altered collagen organization.
• Current histological methods for fibrosis assessment are invasive and provide limited qualitative data.

Purpose of the Study:

• To quantitatively evaluate myocardial fibrosis using 3D imaging of the collagen network.
• To apply non-linear optical microscopy techniques, specifically Two-Photon Excitation (TPE) and Second Harmonic Generation (SHG), for fibrosis assessment.
• To develop a 3D quantitative analysis for fibrosis in a rat heart failure model.

Main Methods:

• Utilized Two-Photon Excitation (TPE) microscopy for endogenous fluorophore excitation.
• Employed Second Harmonic Generation (SHG) microscopy to image collagen structure without staining.
• Focused on backward SHG (B(SHG)) for potential in vivo applications.
• Analyzed collagen I fibrosis in rat myocardium post-myocardial infarction.

Main Results:

• Demonstrated a 5-fold increase in collagen I fibrosis in remote surviving myocardium 20 weeks post-infarction.
• Observed significant changes in the spatial distribution of fibrosis.
• Validated the use of B(SHG) for quantitative fibrosis measurement.

Conclusions:

• 3D quantitative analysis using TPE and SHG microscopy offers a powerful tool for assessing cardiac fibrosis.
• The technique provides insights into the morphology and progression of cardiac disease.
• Backward SHG (B(SHG)) shows promise for in vivo cardiac fibrosis monitoring.