The aim of this study was to assess the effects of early thymoglobulin administration on cardiocyte nuclear status in orthotopic heart transplant (OHT) recipients.
Material and methods: We investigated endomyocardial biopsies (EMBs) from 31 OHT recipients and 10 control cases. OHT patients were divided into the standard group who were treated without thymoglobuline; an ATG group who received thymoglobulin electively, and a standard+ATG group who were administered thymoglobulin upon a drop in renal function. We evaluated only EMBs obtained at 1 and 4 weeks after OHT showing no significant rejection (ISHLT grades 0 to 1B). The morphometric studies were performed using a computerized, automated Quantimet image analysis system. Overall, 1750 cardiocyte nuclei were quantitated for area, length, breadth, perimeter, chromatin median grey level, and fullness factor. Statistical analysis was performed using the Mann- Whitney U test, the Wilcoxon test, and discriminant analysis.
Results: All OHT groups showed significantly higher values (indicating nucleus enlargement) than the control group. All factors suggesting myocardial hypertrophy were significantly higher in the standard group; however, they decreased significantly with time. In contrast, the nuclear geometric parameters were significantly lower and stable throughout the study in the ATG group. The results of the standard+ATG group were intermediate, and their normalization as incomplete at the week 4 examination. Discriminant analysis revealed the closest Mahalanobis distance between control and ATG groups both at and weeks 1 and 4 after OHT.
Conclusion: Thymoglobulin administered early after surgery protected cardiocyte hypertrophy in heart transplant recipients, mitigating graft ischemic damage.