Biomedical subjects

Antoni Bayes de Luna

Publications and source records attributed to Antoni Bayes de Luna.

4 recordsLinked to original sources

PubMed2007

Chimerism and microchimerism of the human heart: evidence for cardiac regeneration.

For decades, it has been widely accepted that the heart is a terminally differentiated organ that is unable to regenerate. Studies of recipients of hearts donated by other humans have shed light on the regenerative potential of the human heart. Investigators have been able to trace the Y chromosome by fluorescence in situ hybridization or polymerase chain reaction, or both, in sex-mismatched heart recipients. Cardiac chimerism has been reported, with concentrations of chimeric cells ranging from 0.04% to 10.0%. Cardiac chimerism after bone marrow or progenitor cell transplantation has also been reported to a low extent (approximately 0.20%), suggesting that a fraction of the extracardiac cells that colonize the myocardium are of bone marrow origin. Cardiac chimerism after pregnancy with male offspring (fetal cell microchimerism) has also been demonstrated. Cells of fetal origin have been shown to be capable of differentiating into myocardial cells. Collectively, we show that chimerism studies provide a proof of concept of a process that it is likely to be part of normal cardiac homeostasis in humans but apparently insufficient for cardiac repair in diseased hearts.

Chimerism↗

PubMed2005

Identification of male cardiomyocytes of extracardiac origin in the hearts of women with male progeny: male fetal cell microchimerism of the heart.

BACKGROUND: Fetal progenitor cells may cross the placenta during pregnancy, persist for decades in the maternal bloodstream, and find a microenvironment conducive to colonization in a variety of maternal solid organs. Whether extracardiac fetal progenitors are present in the heart of women with male issue is unknown. METHODS: The hearts from 2 non-pregnant women who had given birth to 2 and 3 male children, respectively, were studied. Myocardial specimens from 2 men and 2 women (without history of pregnancies) were used as controls. Real time polymerase chain reaction was performed to amplify the SRY gene located at the Y chromosome. Fluorescence in situ hybridization (FISH) with probes specific for X and Y chromosomes was combined with alpha-actin immunohistochemistry to identify cardiac muscle cells. Histocompatibility studies were conducted in both patients and their male relatives. RESULTS: The SRY gene was amplified in the myocardium of both patients. FISH analysis showed clear evidence of male cells with the typical cardiomyocyte phenotype within the myocardium. X- and Y-chromosome bodies in the nuclei were found in 0.25% and 0.20% of cells, respectively. Increased human leukocyte antigen compatibility was observed between patients and their sons. CONCLUSIONS: This study identified male cardiomyocytes of extracardiac origin, presumably fetal, in the hearts of 2 women with male progeny. Fetal progenitor cells may colonize the heart and under appropriate microenvironmental stimuli, differentiate into cardiomyocytes.

Cardiomyopathy, Dilated↗

PubMed2005

QT dynamics and variability.

Repolarization dynamics and variability are of increasing interest as Holter-derived parameters reflecting changes in myocardial vulnerability and contributing to increased risk of arrhythmic events and sudden death. Repolarization dynamics is usually defined as phenomenon describing and quantifying QT adaptation to changing heart rate. The analysis of QT-R-R slopes in long ECG recordings is one of the ways to evaluate repolarization dynamics. Increased QT-R-R slopes are frequently observed in patients at risk for cardiac death and arrhythmic events: postinfarction patients, long QT syndrome patients, patients with nonischemic cardiomyopathy as well as in patients taking drugs affecting repolarization. QT variability reflects beat-to-beat changes in repolarization duration and morphology and such changes can be quantified using a number of algorithms currently in various phases of development and validation. Increased QT variability is observed in several conditions with increased risk of arrhythmias. Recent data from MADIT II indicate that increased QT variability is a powerful predictor of arrhythmic events in postinfarction patients with left ventricular dysfunction. More studies are needed to determine further the potential clinical usefulness for diagnosing patients and for risk stratification purposes using both QT dynamics and QT variability methods, and compare these methods with exercise-induced T wave alternans.

Arrhythmias, Cardiac↗

PubMed2002

Host cell-derived cardiomyocytes in sex-mismatch cardiac allografts.

BACKGROUND: Mesenchymal precursor cells are able to respond to tissue signals and differentiate into a phenotype characteristic of mature cells of that tissue. We sought to investigate whether adult human cardiomyocytes can be derived from recipient precursor cells in sex-mismatched cardiac allografts. METHODS: We studied four male patients who received hearts from female donors, and four female patients who received an allograft from a male donor. Four sex-matched transplant patients, two of each sex served as controls. Combined fluorescence in situ hybridization with probes specific for X- and Y-chromosomes and immunohistochemistry with alpha-actin was used to identify cardiac muscle cells 4 and 12 months after transplantation. Slides were examined with a fluorescence microscope to detect the presence of male cells with one X and one Y signal in the nucleus, and female cells containing two X signals. RESULTS: Mature cardiomyocytes from the host (1-2%) were found in five endomyocardial biopsy specimens at 4 months, and in three specimens at 12 months. In addition, recipient cells negative for cytoplasmic alpha-actin were also identified (1-21% per slide). The number of infiltrating recipient cells was not associated with the degree of rejection of the sample or with the number of prior rejection episodes. Echocardiographic evaluation showed no improvement in cardiac performance in hearts from patients with more than 10% chimeric recipient cells. CONCLUSIONS: Our data confirm the existence of mature cardiomyocytes derived from host cells, likely mesenchymal precursors, in the adult cardiac allograft in vivo.

Actins↗