DNA content, apoptosis and mitosis in transplanted human hearts.

Aim of the study: To analyze the changes in DNA content, the percentage of apoptosis and the nuclear mitotic frequency of myocytes in transplanted human hearts. Methods: Twenty-three transplanted hearts were obtained from 22 patients. The mean interval between transplantation and death was 649 days (ranging from 13 to 2558 days). Ten control hearts were selected from individuals whose death was not due to primary heart disease. Tissue samples were obtained from the mid section of the lateral wall of left and right ventricles. DNA content was evaluated on isolated myocardial cells using image cytometry. In situ detection of apoptosis was performed by the terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling (TUNEL) technique. Mitotic figures were examined by staining the nuclear DNA with YOYO-1 iodide. Myocytes were distinguished from stromal cells by using antibodies reacting with a-sarcomeric actin. Results: Comparing with control hearts, the myocytic changes after cardiac transplantation are characterized by: 1) a decrease in mononucleated myocytes and an increase in binucleated and multinucleated myocytes; 2) a decrease in diploid myocytic nuclei and a distinct augmentation of intermediate ploidies; 3) an increase in myocytic nuclei in DNA ploidies higher than 4c; 4) a marked augmentation of percentage of apoptotic myocytes and 5) an increased frequency of nuclear mitosis of myocytes; this fact appears as a declining phenomenon after six months of cardiac transplantation. Conclusion: After cardiac transplantation the DNA content of myocytes shows two completely different aspects: 1) a distinct increase in subdiploidy and intermediate ploidies related to myocyte injury induced by apoptosis and necrosis; 2) an increase in multinucleation, polyploidization and mitotic proliferation. Both myocyte growth and myocyte injury alter the function of the allograft and contribute to adaptation or failure of the graft. Furthermore, a relevant difference of age between the recipient and the donor may lead to a more marked myocyte damage and a lower myocyte growth. This tendency provides an evidence that age matching could be an important aspect in selecting the donor for the recipient.

In vitro cultures of pathological thyroid cells: a powerful diagnostic technique.

In order to get a correct predictivity from molecular and functional markers in neoplastic disease, cell cultures, correspondent to in vivo existing populations, should be available. The difficulty, as yet, to correlate in vivo conditions with in vitro molecular and functional markers, represents a hurdle for a better prognosis in several neoplastic diseases. We tackled the problem establishing cultures from surgical samples of human thyroid glands bearing various pathologies (pathological diagnosis were obtained for all samples). Cells were frozen after 2 passages, and molecular markers (thyroglobulin, TPO, TTF-1 and PAX-8) and functional parameters (TSH-dependent cAMP production and thymidine incorporation) were investigated after thawing. The "in vitro profile" (functional parameters and molecular markers) was found to correlate with the pathological diagnosis and the degree of differentiation of the starting specimens. The data presented suggest that our culture technique allows in vitro growth of cell populations that may be used to perform functional assays and may make the molecular characterization of pathological samples easier. These findings could be especially useful to better define prognosis and also help to develop innovative therapies.

DNA Content in End-Stage Heart Failure.

AIM OF THE STUDY: Heart failure is the final clinical presentation of a variety of cardiovascular diseases, such as coronary artery disease, hypertensive, toxic, and inflammatory heart disease. However, the cellular mechanisms responsible for the progressive deterioration of myocardial function observed in heart failure remain unclear and may result from cell death (programmed or not) and from an increase in number of nuclei and in the degree of their ploidy. METHODS: We examined thirty-eight explanted hearts obtained during transplantation for DNA content in the myocytic population. All thirty-eight patients had severe chronic heart failure: 23 had idiopathic dilated cardiomyopathy, and 15 had ischemic cardiomyopathy. Ten hearts of people whose death was not due to primary heart disease or as a consequence of major risk factors of coronary artery disease, including hypertension, diabetes, obesity, or severe atherosclerosis, were used as controls. DNA content in the myocytic population was evaluated using Image Cytometry. RESULTS: The DNA content per nucleus and per myocyte in cardiomyopathic hearts are characterized by: a) a decrease of the diploid DNA content of myocytic nuclei; b) an increase of DNA ploidies higher than 4c; c) a decrease in mononucleated myocytes; d) an increase in binucleated and multinucleated myocytes. The changes are more prominent in dilated cardiomyopathy. e) The total ploidy index, used to calculate the total DNA content, is related to heart weight and ventricular weight. CONCLUSIONS: Ischemic and dilated cardiomyopathies result in reduction of ventricular mass-to-chamber volume ratio and in discrete foci of myocyte cell death, leading to an elevation in systolic and diastolic stress on the remaining viable cells. Therefore mechanical stimuli generated by global and local loading abnormalities associated with end-stage failure may contribute to activate genes implicated in cell proliferation. Observations in this investigation are consistent with recent results documenting that in the presence of overload conditions the myocytes may retain their capacity to proliferate throughout life and this growth reserve mechanism may become operative in response to severe myocardial dysfuntion and overt failure. Polyploidization and multinucleation are prominent phenomena in the end-stage of ischemic and dilated cardiomyopathy in humans.

Parathyroid adenomas and malignant neoplasms: coincidence or etiological association?

OBJECTIVE: To evaluate the possible association between primary hyperparathyroidism and malignant neoplasms. DESIGN: An historical cohort study. SETTING: The only Regional General Hospital of the Province of Udine, Italy (population = 500.000). PARTICIPANTS: All the 101 patients with surgically treated parathyroid adenomas. MAIN OUTCOME MEASURE: The incidence rate of malignant tumor was calculated for this cohort based on the number of incidence cases and the person-years at risk. Standardized morbidity rate ratios (SMR) were calculated to infer the cancer relative risk of the study cohort as compared with the general population. RESULTS: A total of 13 cases of malignant neoplasms were ascertained among cohort members. The overall number of observed cases of malignancy did not exceed the number of expected cases (SMR = 1.0). However, strong and statistically significant direct associations were found with bladder cancer (SMR = 5.1) and polycythemia vera (SMR = 62.5). CONCLUSIONS: Due to the magnitude of the associations between parathyroid and bladder cancer and polycythemia vera, it is unlikely that they might be explained completely by bias or chance. Rather, biologically plausible explanations were identified. Particularly, non-paraneoplastic hypercalcemia due to primary hyperparathyroidism may increase the risk of these malignancies.