Different role of advanced glycation end products in pathology of transplanted heart in patients with or without diabetes mellitus type 2

BACKGROUND

Aim of the study was to localize advanced glycation end products (AGEs) in late endomyocardial biopsies (EMBs) of orthotopic heart transplant (OHT) recipients with and without diabetes mellitus (DM) to correlate their presence with acute rejection episodes (ARE) and cardiac allograft vasculopathy (CAV).

MATERIALS AND METHODS

Elective EMBs were performed at 3 years post-OHT in 64 subjects, with DM (59 M/5 F), of overall mean age of 49 +/- 8 years and 24 patients, without DM (21 M/3 F), of overall mean age of 42 +/- 10y. Localization of myocardial AGEs in paraffin sections was assessed immunochemically using mouse monoclonal anti-AGE antibodies (clone 6d12) on cardiomyocytes, stromal cells, connective tissue elements and capillaries.

RESULTS

The occurrence of AGEs was similar in DM versus non-DM subjects: namely, cardiocytes 73% versus 63%, stroma 33% versus 33%, connective tissue 13% versus 9%, and capillaries 31% versus 33%, respectively. Only in the DM group. The acute rejection episodes and mean EMB score significantly correlated with AGE presence in cardiomyocytes (r = 0.29/0.3; P = .02/.02; Spearman). There was no relation between AGE occurrence and CAV diagnosis among DM subjects, while the time free from angiographically confirmed CAV or a CAV-related event was significantly shorter among non-DM recipients without AGEs in capillaries and/or cardiocytes (P = .014/.017/.014/.03, respectively; log-rank).

CONCLUSION

AGE occurrence in OHT recipients with DM was related to ARE, but not to CAV; in contrast, among non-DM patients it was not correlated with ARE, but their absence predicted CAV.

Cardiocyte nuclear chromatin density correlates with transplanted heart left ventricular mass

INTRODUCTION

Cardiocyte hypertrophy is accompanied by polyploidy, seen as a decrease in chromatin density in the enlarged nucleus. Repeated biopsies of a transplanted heart offer the possibility of a dynamic evaluation of these phenomena. The aim of this work was an evaluation of cardiocyte nuclear chromatin density in transplanted hearts during long-term follow-up.

MATERIALS AND METHODS

The material encompassed myocardial biopsy specimens taken during the first week, first month, and then on an annual basis up to 10 years after surgery. Only biopsy specimens with no rejection were considered (grade "0" International Society for Heart and Lung Transplantation [ISHLT] 122 biopsy specimens). The control group consisted of 7 donor heart specimens. We evaluated the optical density-mean gray level-of cardiomyocyte nuclear chromatin. We determined correlations of this index with the nuclear area, and with left ventricle ultrasound measurements, using correlation analysis.

RESULTS

The chromatin mean gray level decreased with time, correlating positively with interventricular septum thickness, left ventricle posterior wall diameter, and left ventricular mass. Analysis of individual periods showed a significant positive correlation of the mean grey level with the cardiocyte nuclear surface in year 3, 4, and 9 after transplantation, thereby suggesting the occurrence of polyploidy at those times. The significant negative correlation of these values (1 week and 1 year) indicated normalization of early cardiocyte hypertrophy.

CONCLUSIONS

With the passage of time chromatin condenses, leading to pyknosis. The activity of cardiocyte chromatin correlated with left ventricular hypertrophy. Compensatory cardiomyocyte polyploidy is a periodical phenomenon.

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.

Cardiocyte nucleus shape as an indicator of heart graft aging

Morphometric publications based on the measurement of cardiocyte nuclei indicated their progressive hypertrophy ignoring, however, their shape, which is a deciding factor for the microscopic-based diagnosis of hypertrophy. We sought was to demonstrate how the shapes of cardiocyte nuclei change over time and correlate them with the thickness of the interventricular septum, (IVS) the biopsy site.

MATERIAL

We evaluated myocardial biopsies taken in the first week, first month, and then annually until posttransplant year 10. Only biopsies with no rejection were considered: grade "0" ISHLT (122 biopsies). The control group encompassed fragments from seven donor hearts.

METHODS

Cardiomyocyte nuclei were evaluated morphometrically. We calculated the length, breadth, perimeter, roundness, elongation, and fullness factors for correlation with the IVS thickness, and selected indices. The relationships between karyometry and IVS thickness (measured by ultrasound) as well as time were calculated by Spearman's correlation test.

RESULTS

Among the examined indices, only nuclear length did not correlate significantly with follow-up time. Among the remaining indices, the strongest correlations with time were observed with regard to breadth (r = 0.214), perimeter (r = 0.150), roundness (r = -0.06) and fullness (r = 0.06), and finally elongation (r = 0.02). The decreasing thickness of the interventricular septum (r = -0.31) showed a weak correlation only with the cardiocyte nuclear length (r = -0.05).

CONCLUSION

Graft aging imitates hypertrophy inasmuch as cardiocyte nuclei become wider despite the decreased thickness of the interventricular septum. Therefore, karyometric measurements do not reflect myocardial morphology.