Pivotal karyometric measurements in different types of cardiomyopathic morphology: study of hearts explanted from transplant recipients

BACKGROUND

Morphometric studies based on the measurement of cardiocyte nuclei have focused on progressive hypertrophy rather than shape, which is a deciding factor for the diagnosis of hypertrophy in myocardial diseases. The aim of this research was to demonstrate how the digital morphology of cardiocyte nuclei change correlated with the type of myocardial pathology.

MATERIALS AND METHODS

The study groups encompassed 7 hearts with dilated cardiomyopathy (DCM) and 8 hearts with ischemic heart disease (IHD) which were explanted. A comparative group consisting of myocardial hypertrophy was contrasted with a control group of donor heart fragments. Cardiocyte nuclei were evaluated morphometrically on histologic slides. We calculated the nuclear area, length, breadth, perimeter, roundness, elongation, fullness factors, and nuclear chromatin mean gray level. The results were subjected to discriminant analysis.

RESULTS

All karyometric measurements analyzed by backward discriminant analysis showed only 2 powerful factors: nuclear breadth and chromatin mean gray level. The Mahalanobis distance showed the proximity of control and hypertrophy groups, whereas differences between IHD and DCM were nonsignificant.

CONCLUSION

The lack of karyometric differences between IHD and DCM suggested a common morphologic response for long-lasting progressive injury. The main morphologic differences were dependent on nuclear chromatin activity/stainability and nuclear breadth, suggesting darker and thinned nuclei in normal and adaptative stages and irregular brighter nuclei in cardiomyopathies.

Differences in antiapoptotic, proliferative activities and morphometry in dilated and ischemic cardiomyopathy: study of hearts explanted from transplant recipients

BACKGROUND

Antiapoptotic as well as replacement and proliferative mechanisms take place in the myocardium in dilated cardiomyopathy (DCM) and ischemic heart disease (IHD). We sought to estimate antiapoptotic, proliferative and replacement activities in cardiomyopathies.

MATERIALS

The study groups included seven hearts with DCM and eight with IHD, which had been explanted at the time of transplantation. The comparator group consisted of cases of myocardial hypertrophy and the control group, donor fragments.

METHODS

Antiapoptotic and proliferative responses were determined immunohistochemically as Bcl-2 and Ki67 expression by semiquantitative assessment of the intensity of staining. We also measured and statistically analyzed the integrative morphometric measurements of the fraction of fibrosis area, the nucleosarcoplasmic ratio, and cardiocyte diameter.

RESULTS

No Bcl-2 expression was observed in the controls. The strongest reaction was seen in the DCM group, then in the IHD, and in the comparator group of myocardial hypertrophy. Proliferative activity was seen only in endocardial and interstitial fibroblasts in DCM and IHD cases. The cardiocyte diameter showed no statistical association between myocardial hypertrophy and IHD, or IHD and DCM, whereas the nucleosarcoplasmic ratios were significantly different from control groups for all comparisons. Myocardial fibrosis showed the highest values in DCM and IHD. Discriminant analysis showed the value of interstitial fibrosis and cardiocyte diameter to categorize the analyzed groups.

CONCLUSIONS

Antiapoptotic Bcl-2 activity seemed to play an important role in cardiocyte preservation, while proliferative activity was resticted to interstitial connective tissue cells as a replacement process. Myocardial Bcl-2 expression, the extent of myocardial fibrosis, and cardiocyte diameter may serve as additional diagnostic tools to differentiate cardiomyopathies.

Remodeling of human transplanted myocardium in ten-year follow-up: a clinical pathology study

Remodeling taking place in transplanted myocardium leads to a change in the number of cardiocytes. Ultrasound measurements and biopsy evaluation should reflect their loss and compensation. We sought to evaluate the morphology of the transplanted heart upon long-term follow-up.

MATERIAL AND METHODS

Myocardial biopsies were obtained in the first week, first month, and then annually for 10 years from transplantation that did not show rejection (grade "0" ISHLT, 122 biopsies). The control group encompassed 7 donor heart fragments. Proliferation in biopsies was evaluated with Ki67 (M7240, DAKO), cardiocyte hypertrophy by measuring their diameter, the surface area of the nuclei, nuclear-sarcoplasmic index, and stromal fibrosis evaluated as the surface area fraction. Ultrasound measurements included diastolic thickness of the interventricular septum, posterior wall of the left ventricle, and left ventricular mass. The correlation of measurements with time from transplantation was evaluated using Spearman's test.

RESULTS

A positive Ki67 reaction was observed in fibroblasts and endothelial cells. The increased cardiocyte nuclear area correlated with the time elapsed since transplantation (r = 0.2; P < .05) with a simultaneous decrease in cardiocyte thickness (r = -0.3; P < .05), without changes in the nuclear-cytoplasmic index (r = 0.02; P > .05). Stromal fibrosis also increased (r = 0.1; P < .05). Ultrasound measurements of the left ventricle showed a decreased tendency with the passage of time (r = -0.2 to -0.3; P < .05).

CONCLUSION

A transplanted heart does not undergo hypertrophy but rather fibrous atrophy with apparent compensatory hypertrophy of the cardiomyocytes.

Nuclear Mean Gray Level and Chromatin Distribution Changes in Cardiomyocytes of Heart Transplant Recipients Suffering From Acute Cellular Rejection

BACKGROUND

Distribution and staining of the nuclear chromatin are sensitive indicators of changes in physiology and pathology of cells. However, their use in heart transplant recipients is rare. The aim of this study was to compare cardiomyocyte status in heart transplant recipients suffering from moderate acute cellular rejection and subjects without signs of active cellular rejection.

MATERIALS AND METHODS

One hundred twenty-nine endomyocardial biopsy samples from 43 heart transplant recipients (no later than 6 months after surgery) were evaluated. Overall, 3235 cardiomyocytic nuclei were analyzed using the Quantimet image analysis system to assess the mean gray level: 1584 nuclei were found in biopsies without signs of rejection or with nonsignificant rejection (ISHLT grades 0, 1A, and 1B), whereas the remaining 1651 nuclei were measured from biopsies showing ISHLT grade 3A (significant rejection). Additionally, the chromatin distribution was assessed in all eligible nuclei.

RESULTS

The mean gray level was markedly increased in nuclei from biopsy samples with significant rejection (182.6 vs 112.5, P < .001, Mann-Whitney U test). Moreover, the analysis of chromatin distribution revealed significantly more frequent chromatin marginalization and irregular distribution in rejecting subjects (P < .001, chi-square test).

CONCLUSION

Inflammatory stimulation of cardiomyocytes during acute cellular rejection of the transplanted heart influences the chromatin distribution in the nuclei, which may have an additional value, when assessing the severity of rejection.