Cardiac Fibrosis: New Treatments in Cardiovascular Medicine
Cardiac Fibrosis: New Treatments in Cardiovascular Medicine
Historically, the only measures of cardiac fibrosis have been echocardiograms that indirectly measure left ventricle mass and endomyocardial biopsies that measure collagen volume fraction (CVF). Newer techniques involve laboratory assessment of biomarkers and cardiac imaging.
Several biomarkers for fibrosis have been identified, most of which are focused on ECM structure. Researchers can measure biomarkers of the synthesis and degradation of collagen types I and III, the main components of ECM. Collagen types I and III are synthesized as pro-collagens, which are then processed into mature collagen molecules by a peptidase cleaving their propeptide domain. During collagen synthesis, propeptides from the amino-terminals (PINP and PIIINP) or carboxyterminals (PICP and PIIICP) of collagen types I and III are released and measured as biomarkers. During collagen degradation, telopeptides in the amino-terminals (NITP, NIIITP) or carboxy-terminals (CITP, CIIITP) of collagen types I and III are cleaved and act as biomarkers.
Biomarkers may be used to identify fibrosis before symptoms of disease are present, as well as to assess the efficacy of medications. Biomarkers are commonly used as endpoints in clinical trials.
MRI is useful for visualizing certain types of fibrosis. Contrast-enhanced cardiac MRI can readily visualize "patchy," or regional, myocardial fibrosis from MI or infiltration. Diffuse fibrosis is much more difficult to visualize, and research into enhanced MRI techniques may prove beneficial in identifying this and other forms of fibrosis. Other imaging techniques that have shown promise in identifying cardiac fibrosis include single photon emission CT and positron emission tomography scanning; more studies are required, however.
Assessment of Fibrosis
Historically, the only measures of cardiac fibrosis have been echocardiograms that indirectly measure left ventricle mass and endomyocardial biopsies that measure collagen volume fraction (CVF). Newer techniques involve laboratory assessment of biomarkers and cardiac imaging.
Several biomarkers for fibrosis have been identified, most of which are focused on ECM structure. Researchers can measure biomarkers of the synthesis and degradation of collagen types I and III, the main components of ECM. Collagen types I and III are synthesized as pro-collagens, which are then processed into mature collagen molecules by a peptidase cleaving their propeptide domain. During collagen synthesis, propeptides from the amino-terminals (PINP and PIIINP) or carboxyterminals (PICP and PIIICP) of collagen types I and III are released and measured as biomarkers. During collagen degradation, telopeptides in the amino-terminals (NITP, NIIITP) or carboxy-terminals (CITP, CIIITP) of collagen types I and III are cleaved and act as biomarkers.
Biomarkers may be used to identify fibrosis before symptoms of disease are present, as well as to assess the efficacy of medications. Biomarkers are commonly used as endpoints in clinical trials.
MRI is useful for visualizing certain types of fibrosis. Contrast-enhanced cardiac MRI can readily visualize "patchy," or regional, myocardial fibrosis from MI or infiltration. Diffuse fibrosis is much more difficult to visualize, and research into enhanced MRI techniques may prove beneficial in identifying this and other forms of fibrosis. Other imaging techniques that have shown promise in identifying cardiac fibrosis include single photon emission CT and positron emission tomography scanning; more studies are required, however.
Source...