carbocyanines and Fibrosis

There is a critical need for techniques that directly monitor protein synthesis within cells isolated from normal and diseased tissue. Fibrotic disease, for which there is no drug treatment, is characterized by the overexpression of collagens. Here, we use a bioinformatics approach to identify a pair of glycine and proline isoacceptor tRNAs as being specific for the decoding of collagen mRNAs, leading to development of a FRET-based approach, dicodon monitoring of protein synthesis (DiCoMPS), that directly monitors the synthesis of collagen. DiCoMPS aimed at detecting collagen synthesis will be helpful in identifying novel anti-fibrotic compounds in cells derived from patients with fibrosis of any etiology, and, suitably adapted, should be widely applicable in monitoring the synthesis of other proteins in cells.

Topics: Animals; Carbocyanines; Cells, Cultured; Collagen; Fibroblasts; Fibrosis; Fluorescence Resonance Energy Transfer; Fluorescent Dyes; Humans; Kinetics; Mice; Mice, Knockout; Microscopy, Confocal; PTEN Phosphohydrolase; RNA, Transfer, Gly; RNA, Transfer, Pro; Transfection

Using molecular imaging techniques, we examined interstitial alterations during postmyocardial infarction (MI) remodeling and assessed the efficacy of antiangiotensin and antimineralocorticoid intervention, alone and in combination.. The antagonists of the renin-angiotensin-aldosterone axis restrict myocardial fibrosis and cardiac remodeling after MI and contribute to improved survival. Radionuclide imaging with technetium-99m-labeled Cy5.5 RGD imaging peptide (CRIP) targets myofibroblasts and indirectly allows monitoring of the extent of collagen deposition post-MI.. CRIP was intravenously administered for gamma imaging after 4 weeks of MI in 63 Swiss-Webster mice and in 6 unmanipulated mice. Of 63 animals, 50 were treated with captopril (C), losartan (L), spironolactone (S) alone, or in combination (CL, SC, SL, and SCL), 8 mice received no treatment. Echocardiography was performed for assessment of cardiac remodeling. Hearts were characterized histopathologically for the presence of myofibroblasts and thick and thin collagen fiber deposition.. Acute MI size was similar in all groups. The quantitative CRIP percent injected dose per gram uptake was greatest in the infarct area of untreated control mice (2.30 +/- 0.14%) and decreased significantly in animals treated with 1 agent (C, L, or S; 1.71 +/- 0.35%; p = 0.0002). The addition of 2 (CL, SC, or SL 1.31 +/- 0.40%; p < 0.0001) or 3 agents (SCL; 1.16 +/- 0.26%; p < 0.0001) demonstrated further reduction in tracer uptake. The decrease in echocardiographic left ventricular function, strain and rotation parameters, as well as histologically verified deposition of thin collagen fibers, was significantly reduced in treatment groups and correlated with CRIP uptake.. Radiolabeled CRIP allows for the evaluation of the efficacy of neurohumoral antagonists after MI and reconfirms superiority of combination therapy. If proven clinically, molecular imaging of the myocardial healing process may help plan an optimal treatment for patients susceptible to heart failure.

Topics: Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Animals; Captopril; Carbocyanines; Cardiovascular Agents; Disease Models, Animal; Drug Therapy, Combination; Echocardiography; Fibrillar Collagens; Fibroblasts; Fibrosis; Losartan; Mice; Mineralocorticoid Receptor Antagonists; Myocardial Infarction; Myocardium; Oligopeptides; Predictive Value of Tests; Spironolactone; Technetium; Tomography, Emission-Computed, Single-Photon; Ventricular Function, Left; Ventricular Remodeling

Topics: Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Carbocyanines; Cardiovascular Agents; Drug Therapy, Combination; Echocardiography; Fibrillar Collagens; Fibroblasts; Fibrosis; Heart Failure; Humans; Mineralocorticoid Receptor Antagonists; Myocardial Infarction; Myocardium; Oligopeptides; Predictive Value of Tests; Technetium; Tomography, Emission-Computed, Single-Photon; Ventricular Function, Left; Ventricular Remodeling