Re-expression of alpha skeletal actin as a marker for dedifferentiation in cardiac pathologies.

Differentiation of foetal cardiomyocytes is accompanied by sequential actin isoform expression, i.e. down-regulation of the 'embryonic' alpha smooth muscle actin, followed by an up-regulation of alpha skeletal actin (alphaSKA) and a final predominant expression of alpha cardiac actin (alphaCA).

Cardiotin localization in mitochondria of cardiomyocytes in vivo and in vitro and its down-regulation during dedifferentiation.

Background: Cardiotin expression is observed in adult cardiac tissue. In the present study, we provide evidence for the specific localization of cardiotin in cardiac mitochondria and for its down-regulation during adaptive remodeling (dedifferentiation) of cardiomyocytes.

Methods: Immunocytochemistry was used to study cardiotin localization in adult rabbit papillary muscle, in late-stage embryonic rabbit left ventricular tissue, and in left ventricle samples of rabbits suffering from pressure and volume overload.

Partial cell fusion: a newly recognized type of communication between dedifferentiating cardiomyocytes and fibroblasts.

Objective: Fibroblasts have been shown to couple to neonatal cardiomyocytes in heterocellular cultures through functional gap junctions. Our objective was to provide evidence for an additional type of heterocellular communication between fibroblasts and adult cardiomyocytes in vitro and in vivo.

Methods: The contact areas in heterocellular co-cultures were evaluated by specific labeling and the intercellular communication was studied using preloading of fibroblasts with tracer molecules.

Smoothelin expression during chicken embryogenesis: detection of an embryonic isoform.

Two isoforms of a novel smooth muscle cell (SMC) -specific cytoskeletal protein, smoothelin, have been described. In the adult chick, the 55-kDa smoothelin-A is expressed in visceral SMC, whereas the 120-kDa smoothelin-B is the major product in vascular SMC. Chicken was chosen to study smoothelin expression during embryogenesis and neonatally.

Assay for human matrix gla protein in serum: potential applications in the cardiovascular field.

Matrix Gla protein (MGP) is synthesized in a vitamin K-dependent way in smooth muscle cells of the healthy vessel wall, and its mRNA transcription is substantially upregulated in atherosclerotic lesions. Here we report the preparation of a monoclonal antibody against human MGP and its use in an enzyme-linked immunosorbent assay. The intra-assay and interassay coefficients of variation in serum samples were 5.