Identification and Characterization of Two Genes (MIP-1β, VE-CADHERIN) Implicated in Acute Rejection in Human Heart Transplantation

Background— Genes and mechanisms of action involved in human acute rejection after allogeneic heart transplantation remain to be elucidated. The use of a murine allograft model in tandem with cDNA arrays and quantitative real-time polymerase chain reaction (Q-PCR) can greatly help in identifying key genes implicated in human heart acute rejection.

Methods and Results— Hearts from Balb/c mice were either not transplanted or transplanted heterotopically in the abdomen of Balb/c (isografts) and C57BL/6 (allografts) mice. Histological analysis showed acute rejection only in allografts. Total RNA was extracted from isografts (n=3), allografts (n=4), and not transplanted hearts (n=4); reverse transcribed; and labeled with P32. Each probe was hybridized to cDNA macroarrays. Eight genes were overexpressed and 7 genes were underexpressed in allografts compared with isografts. Macrophage inflammatory protein-1β (MIP-1β), an overexpressed gene, and VE-cadherin, an underexpressed gene, were validated by immunohistochemistry and Q-PCR in the murine models. Genes of interest, validated in the 3 murine groups, were then investigated in human heart tissues. Immunohistochemistry and Q-PCR performed on endomyocardial biopsies after heart transplantation showing no rejection (n=10) or grade IB (n=10) or IIIA (n=10) rejection, according to International Society of Heart and Lung Transplantation criteria, confirmed the results obtained from the murine model.

Conclusions— We have demonstrated that the upregulation of MIP-1β and downregulation of VE-cadherin may strongly participate in human acute heart rejection.

Safety, tolerability, and efficacy of cyclosporine microemulsion in heart transplant recipients: a randomized, multicenter, double-blind comparison with the oil-based formulation of cyclosporine--results at 24 months after transplantation

BACKGROUND

The widespread use of cyclosporine has improved the survival of cardiac transplant patients as a result of reduced morbidity and mortality from rejection and infection. The original oil-based form of cyclosporine demonstrated unpredictable absorption resulting in an increased frequency of acute and chronic rejection in patients with poor bioavailability. The primary end. points of the present, prospective, randomized multicenter, double-blind trial were to compare the efficacy of the micro-emulsion form of cycolsporine (CsA-NL) with the oil-based formulation as determined by cardiac allograft and recipient survival and the incidence and severity of the acute rejection episodes and to determine the safety and tolerability of CsA-NL compared with Sandimmune CsA-(SM) in the study population. The 6-month analysis of the study showed reduced number of CsA-NL patients requiring antilymphocyte antibody therapy for rejection, fewer International Society of Heart and Lung Transplantation grade > or =3A rejections in female patients and fewer infections. Our report represents the final analysis of the results 24 months after transplantation.

METHODS

A total of 380 patients undergoing de novo cardiac transplants at 24 centers in the United States, Canada, and Europe were enrolled in this double-blind, randomized trial evaluating the efficacy and safety of CsA-NL versus CsA-SM. Acute allograft rejection was diagnosed by endomyocardial biopsy and graded according to the International Society of Heart and Lung Transplantation nomenclature. Kaplan-Meier analysis and Fisher's exact test were used for comparisons between groups.

RESULTS

After 24 months, allograft and recipient survival were identical in both groups. There were fewer CsA-NL patients (6.9%) requiring antilymphocyte antibody therapy for rejection than in the CsA-SM-treated patient group (17.7%, P=0.002). There were fewer discontinuations of study drug for treatment failures in the CsA-NL groups (7; 3.7%) compared with the CsA-SM group (18; 9.4%, P=0.037). The average corticosteroid dose was lower in the CsA-NL group (0.37 mg/kg/day) compared with the CsA-SM group (0.48 mg/kg/day, P=0.034) over the 24-month study period. Overall, there was no difference in blood pressure or creatinine between the two study groups.

CONCLUSIONS

The final results of this multi-center, randomized study of two forms of cyclosporine confirmed that there were fewer episodes of rejection requiring antilymphocyte antibodies and fewer study discontinuations for treatment failures in CsA-NL-treated patients compared to those treated with CsA-SM. The use of CsA-NL did not predispose these patients to a higher risk of adverse events.

Thiopurine S-methyltransferase gene polymorphism is predictive of azathioprine-induced myelosuppression in heart transplant recipients

Azathioprine (AZA) is metabolized via the cytosolic enzyme thiopurine S-methyltransferase (TPMT). TPMT activity exhibits genetic polymorphism with four prevalent (75%) mutant alleles TPMT*2 (G238C) and TPMT*3 (A719G and/or G460A) and a wild-type allele TPMT*1. To test the hypothesis that presence of these mutations is associated with greater toxicity of AZA in heart transplant recipients, 30 consecutive patients treated with AZA were followed up for the first month after heart transplant. Mutation of TPMT gene (mutation-specific polymerase chain reaction-based methods) was observed in four patients (A719G: n = 2; A719G plus G460: n = 2). Agranulocytosis did not occur in patients with the wild genotype. It occurred in the two patients with mutation A719G and there was a 40% drop in neutrophils in the two other patients. Discontinuation of AZA in the four mutant patients corrected for the drop. Presence of TPMT mutations is associated with a greater likelihood of agranulocytosis. Determination of these mutations could reduce the risk for hematological side-effects.

Safety, tolerability and efficacy of cyclosporine microemulsion in heart transplant recipients: a randomized, multicenter, double-blind comparison with the oil based formulation of cyclosporine--results at six months after transplantation

BACKGROUND

The introduction of cyclosporine has resulted in significant improvement in the survival of cardiac allograft recipients due to decreased mortality from infection and rejection. The original oil-based cyclosporine formulation exhibits variable and unpredictable bioavailability that correlates with an increased incidence of acute and chronic rejection in those patients in whom this is most pronounced. The primary objectives of this prospective, multicenter, randomized, double-blind study in cardiac transplant patients were: to compare the efficacy of cyclosporine microemulsion (CsA-NL) with oil-based cyclosporine (CsA-SM) as measured by cardiac allograft and recipient survival and the incidence and severity of acute rejection episodes; and to assess the safety and tolerability of CsA-NL compared with CsA-SM in this population. This report represents the analysis of results 6 months after transplantation.

METHODS

A total of 380 patients undergoing their first cardiac transplant at 24 centers in the United States, Canada, and Europe were enrolled in this double-blind, randomized trial examining the safety and efficacy of CsA-NL versus CsA-SM. Rejection was diagnosed using endomyocardial biopsy and were graded according to standardized criteria of the International Society of Heart and Lung Transplantation (ISHLT). Clinical parameters were monitored during the study. Survival and freedom from were used for analysis as was Fisher's exact test for comparisons between groups.

RESULTS

At 6 months after transplantation, allograft and patient survival were the same for both groups. The frequency of ISHLT grade 3A or greater episodes in the two groups was identical. Fewer CsA-NL patients (5.9%) required antilymphocyte antibody (ATG or OKT-3) therapy for rejection compared with the CsA-SM-treated patients (14.1%, P=0.01). Females with ISHLT rejection grade > or = 3A treated with CsA-NL had a 46% lower incidence of rejection compared with the CsA-SM-treated group (31.3% vs. 57.6%, P=0.032). Fewer infections were seen in the CsA-NL. With the exception of baseline and 1 week posttransplant creatinines which were higher in the CsA-NL group, the overall creatinine was not significantly different between the two groups.

CONCLUSIONS

This multicenter, randomized study of cardiac transplant recipients documented less severe rejection (in particular those requiring antibody therapy) and a lower incidence of infection in CsA-NL-treated patients. Results from the female subgroup analysis suggest that the improved bioavailability of CsA-NL might reduce the frequency of rejection episodes in female patients. The use of CsA-NL was not associated with an increased risk of adverse events.

A randomized active-controlled trial of mycophenolate mofetil in heart transplant recipients. Mycophenolate Mofetil Investigators

BACKGROUND

After heart transplantation, 1-year and 5-year survival rates are 79% and 63%, respectively, with rejection, infection, and allograft coronary artery disease accounting for the majority of deaths. Mycophenolate mofetil (MMF), an inhibitor of the de novo pathway for purine biosynthesis, decreases rejection in animals and in human renal transplantation.

METHODS

In a double-blind, active-controlled trial, 28 centers randomized 650 patients undergoing their first heart transplant to receive MMF (3000 mg/day) or azathioprine (1.5-3 mg/kg/day), in addition to cyclosporine and corticosteroids. Rejection and survival data were obtained for 6 and 12 months, respectively. Because 11% of the patients withdrew before receiving study drug, data were analyzed on all randomized patients (enrolled patients) and on patients who received study medications (treated patients).

RESULTS

Survival and rejection were similar in enrolled patients (MMF, n=327; azathioprine, n=323). In treated patients (MMF, n=289; azathioprine, n=289), the MMF group compared with the azathioprine group was associated with significant reduction in mortality at 1 year (18 [6.2%] versus 33 deaths [11.4%]; P=0.031) and a significant reduction in the requirement for rejection treatment (65.7% versus 73.7%; P=0.026). There was a trend for fewer MMF patients to have > or = grade 3A rejection (45.0% versus 52.9%; P=0.055) or require the murine monoclonal anti-CD3 antibody or antithymocyte globulin (15.2% versus 21.1%; P=0.061). Opportunistic infections, mostly herpes simplex, were more common in the MMF group (53.3% versus 43.6%; P=0.025).

CONCLUSIONS

Substitution of MMF for azathioprine may reduce mortality and rejection in the first year after cardiac transplantation.

[Reversible graft dysfunction after cardiac transplantation]

The authors report 3 cases of major graft dysfunction after cardiac transplantation which recovered completely with biventricular mechanical assistance in 4 to 8 days. All three cases were primary biventricular graft failures in patients with normal preoperative pulmonary resistances. These early dysfunctions (with no signs of myocardial infarction on electro- or echocardiography and in the absence of abnormal increased peri-operative enzyme levels) associated with total functional recovery conforming to the definition of the phenomenon of myocardial stunning. These results argue in favour of aggressive management of primary graft dysfunction.

Long conservation organs in heart transplantation: postoperative results and long-term follow-up in fourteen patients

Between 1988 and 1995, 14 heart transplantations were performed after a long preservation period (10 to 13 hours). The transplantation procedure (Shumway) was standard, and our results were achieved through the implementation of a very strict reperfusion technique that included low pressure and low cardiopulmonary bypass output for the first 10 minutes. Three patients died during the postoperative period, and the survival rate was 75% at 1 year and 71% at 5 years. The results obtained with hearts stored for such long periods are comparable to the results obtained with hearts stored for less than 4 hours.

High prevalence of thromoembolic complications in heart transplant recipients. Which preventive strategy.?

Consecutive patients transplanted between January 1984 and December 1988 were followed until August 1992 to detect fatal and nonfatal thromboembolic complications, including sudden death, acute and chronic myocardial infarction, pulmonary and peripheral embolisms, stroke, and thrombophlebitis. The probability of developing such complications was 9.86 per 100 patients per year. The probability of fatal complications was 3.97% per year; the mean interval between transplant and death was 1247 days versus 29.5 days for nonthromboembolic deaths. Thromboembolic deaths represented 5.1% of total mortality at the first year posttransplant but 57, 30, 67 and 73% at the second, third, fourth, and fifth years, respectively. Among the prognosis factors that were analyzed, none was significant predictor of thromboembolic complication. This high prevalence of thromboembolic complications suggests that effective antithrombotic strategy should be defined in heart transplant recipients.

Comparative epidemiologic study of premalignant and malignant epithelial cutaneous lesions developing after kidney and heart transplantation

BACKGROUND

Cutaneous carcinomas are the most frequent cancers in organ transplant recipients.

OBJECTIVE

Our purpose was to compare the epidemiologic data of cutaneous premalignant and malignant epithelial lesions in kidney and heart transplant recipients.

METHODS

A total of 580 kidney and 150 heart transplant recipients were examined for the presence of premalignant and malignant epithelial lesions.

RESULTS

A twofold increase in incidence of premalignant and malignant epithelial lesions was found in heart compared with kidney transplant recipients. Heart transplant recipients were older at transplantation, received more intense immunosuppressive treatment, and had a shorter delay from transplantation to the development of the first lesion. The squamous cell carcinoma/basal cell carcinoma ratio was 2.37:1 in kidney and 1.08:1 in heart transplant recipients. The extracephalic location represented 60% of the premalignant and malignant epithelial lesions in kidney and 30% in heart transplant recipients.

CONCLUSION

Cutaneous premalignant and malignant epithelial lesions in kidney and heart transplant recipients show epidemiologic differences that can tentatively be explained by the older age and the more intense immunosuppressive treatment of heart transplant recipients.

[Value of coronary angiography in the diagnosis of coronary artery disease of the transplanted heart. Coronary angiography and arteriosclerosis of the graft]

The diagnostic value of coronary angiography, a widespread method of detection of transplant coronary artery disease, was studied in 17 cardiac transplant patients with reference to histological examination. In the 6 coronary segments studied, the only significant but weak correlation that was found was for the distal left anterior descending artery: the correlations were not statistically significant in the other 5 segments. Coronary angiography underestimated lesions and false negative results were frequently reported (66 and 27% respectively). The limitations of coronary angiography may be explained by the technical artefacts related to both methods of evaluation and the anatomically diffuse and distal nature of transplant coronary artery atherosclerosis. A more reliable diagnostic method would seem to be required in view of the clinical importance of this pathology.

Spectral analysis of blood pressure variability in heart transplant patients

The cardiac transplant patient provides a unique model for the study of blood pressure variability in the absence of heart rate variability. We examined the harmonic and fractal components of blood pressure variability in 14 heart transplant patients (12 men, 2 women; 21 to 62 years of age) and in age-and sex-matched control subjects during seated rest, supine rest, and supine rest with fixed-pace breathing (12 respirations per minute). Heart rate was faster in transplant patients than in control subjects, with much less heart rate variability (P < .0001). Spectral analysis of blood pressure variability revealed no difference in total power for either systolic or diastolic pressure, but transplant patients had less low-frequency (0 to 0.15 Hz) harmonic spectral power in both systolic (P < .01) and diastolic (P < .03) pressure and more high-frequency power (0.15 to 0.5 Hz) in diastolic pressure than control subjects. The ratio of high-frequency power in diastolic relative to systolic pressure was consistently higher (P < .0001) in the transplant patients (0.29 to 0.51) than in control subjects (0.11 to 0.13). The slope of the fractal component of systolic pressure was approximately 1.8 in both transplant patients and control subjects. This was greater than the slope for heart rate variability (approximately 1.1 in control subjects). These data provide clear evidence of independence of the fractal component of heart rate and blood pressure variabilities in both transplant patients and control subjects. The heart rate component of the arterial baroreflex minimized high-frequency diastolic pressure changes while contributing to low-frequency variations in both systolic and diastolic pressures.

Lack of successful reanimation of pig hearts harvested more than 10 minutes after death

BACKGROUND

The aim of this study was to evaluate the viability of arrested pig hearts harvested after animal death.

METHODS

Hearts (n = 25) were preserved for 2 hours by cold storage (4 degrees C) with St. Thomas' cardioplegic solution no warm ischemia (0 minutes; control) or 10, 20, 30, or 60 minutes of in situ warm ischemia (animal exsanguination). Hearts were then reperfused for 1 hour with whole blood with an in vitro functional testing system. Left ventricular developed pressure and coronary flow were measured during reperfusion. Energetic compound measurements and histologic analysis were performed on tissue biopsy specimens.

RESULTS

After 10- and 20-minute warm ischemia, hearts showed a significant decrease in energetic compounds, a 51% and 73% decreases of left ventricular developed pressure, and 38% and 65% decreases in coronary flow, respectively. After 30 minutes hearts showed irreversible ischemic injury with ultrastructural tissue damage, a large decrease in energetic adenine nucleotide compounds, and an inability to beat more than 15 minutes after reperfusion.

CONCLUSION

We conclude that in contrast with other species, pig hearts harvested 10 minutes or more after animal exsanguination fail to be successfully reanimated.

Importance of initial coronary artery flow after heart procurement to assess heart viability before transplantation

BACKGROUND

The objective of this study was to evaluate different tests of heart viability in a pig model of warm ischemia.

METHODS AND RESULTS

Pig hearts (n = 30) were submitted to 0 (= group I), 10 (group II), 20 (group III), 30 (group IV), and 60 (group V) minutes of in situ warm ischemia (animal exsanguination). Hearts were removed, then flushed with cardioplegic solution for 3 minutes at a fixed pressure of 60 cm H2O, and edema formation, initial coronary flow, and ionic composition (Na+, K+, and Ca++) of coronary sinus effluent were evaluated. Hearts were then stored for 2 hours in a cold (4 degrees C) preservation solution. Myocardial biopsies (and evaluation of energetic index) were performed, then the hearts were reperfused for 30 minutes with whole blood with an in vitro functional testing system. No edema occurred during cardioplegic flush in the hearts in groups I through IV, but a 37 +/- 11% weight increase (P < .001) occurred in hearts in group V. There was a progressive decrease in initial coronary flow with the increase in the duration of warm ischemia (70 +/- 14 mL/min per 100 g of tissue in group I and 52 +/- 9, 41 +/- 16, 25 +/- 11, and 23 +/- 5 mL/min per 100 g, respectively, in groups II through V (P < .01 to P < .001 versus group I). Initial coronary flow was positively correlated with the energetic index (r = .84, P < .001), and the left ventricle developed pressure at reperfusion (r = .90, P < .001). Finally, there were significant differences between hearts in the control group and those in group V for calcium and sodium release (lower in the control group; P < .001 and P < .01, respectively) and for potassium removal (lower in group V, P < .05).

CONCLUSIONS

These data suggest that early measurement of coronary flow after removal of the heart may help to assess heart viability before transplantation. This approach may provide a comprehensive clinical evaluation to increase the number of hearts available for transplantation among those that are rejected in the absence of accurate criteria of viability.

Post-transplant lymphoproliferative disorders with genetic abnormalities commonly found in malignant tumours

Post-transplant lymphoproliferative disorders (PTLD) are potentially fatal complications of organ transplants. Impairment of the immune system by immunosuppressive drugs is the assumed cause of PTLD. The Epstein-Barr virus (EBV) is detected in most of the PTLD studied and is considered as the main aetiological agent. The clinical course of PTLD patients remains unpredictable, some lymphoproliferations regress after discontinuation of the immunosuppressive treatment, others behave as true malignant tumours. The mechanism by which a viro-induced lymphoproliferation evolves to an autonomous tumour remains unclear, and little is known about the genetic changes that occur during this process. We report two cases of fatal EBV-associated PTLD in heart transplant recipients. Both tumours were monoclonal and carried numerous chromosomal abnormalities, including a classic t(8;14)(q24;q32) with rearrangement of the MYC proto-oncogene. One tumour demonstrated an amplification of the proto-oncogene N-MYC. The EBNA2 gene was not expressed in tumoral cells, suggesting that the chromosomal abnormalities contributed the function of EBNA2 in these cells. The morphology of the tumours indicated that the cases presented here were not Burkitt's lymphomas. These findings provide some clues with regard to the genetic changes which lead to a B-cell malignancy in some transplant patients.

The beneficial effect of dietary antioxidant supplementation on platelet aggregation and cyclosporine treatment in heart transplant recipients

To determine whether dietary antioxidant supplementation can reduce platelet reactivity in heart transplant recipients, 20 patients were prospectively randomized to receive either 500 IU vitamin E orally per day in the form of acetate for 2 months or no vitamin E. Blood creatinine (P = 0.01) and lymphocyte count (P = 0.009) significantly decreased only in supplemented patients, whereas the cyclosporine blood level was not modified. Platelet aggregation was stable in control patients but significantly decreased in supplemented patients in response to either thrombin (from 8.3 +/- 0.9% of maximum aggregation to 3.7 +/- 0.7, P = 0.001) or ADP (secondary wave: from 44.7 +/- 5.9% to 33.2 +/- 7.0, P = 0.02). Thus antioxidant supplementation tended to improve immunosuppression (by reducing lymphocyte count), to reduce cyclosporine nephrotoxicity, and to decrease the high thrombotic risk associated with heart transplantation.

Platelet aggregation and HDL cholesterol are predictive of acute coronary events in heart transplant recipients

BACKGROUND

Sudden death (SD) and acute myocardial infarction (AMI) are the main complications limiting long-term survival after heart transplantation (HT). They are unpredictable and, at present, unpreventable. Platelet aggregation (PA) has recently emerged as a significant prognostic indicator in nontransplanted coronary disease patients. The main purpose of the present study was to evaluate to what extent PA could predict SD and AMI in long-term survivors of HT independently of serum lipid levels.

METHODS AND RESULTS

We studied 207 patients. All received triple immunosuppressive therapy. During follow-up, the incidence of SD and AMI was determined, and the independent role of PA as predictor was evaluated with other usual risk factors by a Cox multivariate regression model. There were 11 SDs and 14 AMIs after an average follow-up of 642 days, giving an average incidence rate of 7.3 events per year per hundred patients. By univariate analysis, the most potent predictors were ADP-induced platelet aggregation (positive association) and total cholesterol (negative association). Age and length of time since transplant were not predictors. By multivariate analysis, only the secondary wave of ADP-induced platelet aggregation (P = .001) and high-density lipoprotein cholesterol (P = .03) were independent predictors. The relative risk of SD or AMI based on a comparison between patients with high (> 36%) or low (< 36%) ADP-induced platelet aggregation was 4.3 (95% confidence interval, 1.9 to 9.5, P = .0001).

CONCLUSIONS

This study provides the first demonstration of an association between increased platelet aggregation and subsequent SD or AMI in HT recipients. It suggests that platelets and thrombosis also are implicated in the pathogenesis of AMI and SD in HT recipients. Identification of a safe and effective antiplatelet therapy should be actively pursued.

Increased production of reactive oxygen species in pharmacologically-immunosuppressed patients

HIV-infected patients and transplanted patients share similar immunosuppressed status. Recent insights gained through the field of heart transplantation may help to clarify the role of reactive oxygen species in HIV-infected patients.

Comparison of different techniques of hypothermic pig heart preservation

The aim of this study was to compare several methods of hypothermic heart preservation. Isolated pig hearts were preserved for 24 hours in cold cardioplegic solution (St. Thomas' Hospital modified solution) by continuous perfusion (group I), microperfusion (group II), or simple storage (group III). The findings were then compared with those from hearts harvested and immediately reperfused (the control group). Group III hearts showed lower adenosine triphosphate preservation (0.47 +/- 0.18 mumol/g) than did group I and II hearts and the control hearts (1.86 +/- 0.40, 1.98 +/- 0.27, and 1.84 +/- 0.55 mumol/kg, respectively). Electronic microscopy studies also revealed that the myocardial cells in the group III hearts appeared to be damaged. After the hearts had undergone preservation, myocardial function was studied for 60 minutes under nonworking conditions using an ex vivo functional testing system. For group III, the mean left ventricular developed pressure and ventricular compliance (16 +/- 22 and 63 +/- 48 mm Hg, respectively) differed significantly from those for group I (83 +/- 26 and 0 +/- 0 mm Hg, respectively), group II (83 +/- 33 and 14 +/- 18 mm Hg, respectively), and the control group (115 +/- 13 and 0 +/- 0 mm Hg, respectively). We concluded from our findings that perfusion methods are superior to cold storage but inadequate to maintain heart viability for the long term during hypothermia. These techniques must be improved before they can be adopted for clinical use.

[Pericardium and heart transplantation]

The authors emphasise the role of the pericardium in the post-operative complications of cardiac transplantation: its role is as important as it is underestimated in its frequency, severity and the pathogenic discussions that it induces. This study, based on a retrospective analysis of 191 anatomo-clinical cases (156 autopsies and 35 retransplantations) of patients undergoing cardiac transplantation before the 1/03/1993 including macroscopic and histopathologic analysis of the pericardial lesions, histochemical analysis of the lymphocytic populations, and analysis of associated coronary and myocardial lesions. The results were classified as early or late (after the 75th postoperative day) complications. Early complications included 27 suppurating mediastino-pericarditis (13 aspergillosis and 14 bacterial), 16 autonomous non-infective pericardial complications (6 haemopericardiums, 6 organised compressive haematomas, 4 early constrictive pericarditis) and 9 lymphocytic epicarditis associated with acute myocardial rejection. Late complications included one common constrictive symphysis and 14 reactivated epicarditis associated with transplantation coronary disease (chronic rejection) with associated lymphoplasmocytic nodules and a myocardial vasculitis. These observations suggest two important conclusions: 1) the need for active diagnostic measures to detect pericardial complications in cases of cardiac transplant dysfunction in the early postoperative period with no signs of acute rejection on myocardial biopsy: the presence of epicardial lesions on biopsy should be taken into account and not just assumed to be a postoperative epiphenomenon; 2) the presence of epicarditis due to reactivated epicarditis may cause inextensible hardening of the epicardium which adds to the effects of restrictive cardiomyopathy of chronic rejection.

Fluid-regulating and sympathoadrenal hormonal responses to peak exercise following cardiac transplantation

Orthotopic heart transplantation results in cardiac denervation that can disrupt the normal regulation of hydromineral balance. This study compared the exercise-induced variations in plasma osmolality; atrial natriuretic peptide (ANP), arginine vasopressin (AVP), norepinephrine (NE), epinephrine (E), and dopamine (DA) concentrations; and plasma renin activity (PRA) of six cardiac transplant recipients (HTX) and six healthy age-matched controls (C) submitted to graded upright maximal cycling. Venous blood samples were obtained at rest, at submaximal (70% O2 uptake) and peak exercise, and after 10 and 30 min of sitting recovery. Peak O2 uptake was not different between groups despite lower maximal heart rate in HTX (136 +/- 6 vs. 183 +/- 9 beats/min). Baseline plasma ANP and PRA were higher in HTX (203 +/- 55 pg/ml and 29.9 +/- 7.4 ng.ml-1 x h-1) than in C (71 +/- 17 pg/ml and 5.4 +/- 0.96 ng.ml-1 x h-1); AVP was lower in HTX than in C (1.1 +/- 0.3 vs. 3.2 +/- 0.8 pg/ml; P < 0.05); and circulating E, NE, and DA were not different between groups. Exercise resulted in more marked increases in HTX than in C for ANP (300 vs. 100%), AVP (2,000 vs. 300%), NE (860 vs. 500%), and DA (611 vs. 187%) but not for PRA and a higher E response in C than in HTX (455 vs. 1,258%). These observations confirm that the potential for ANP release to central volume loading is independent of intact cardiac innervation. The exaggerated AVP response in HTX could, however, reflect the absence of inhibitory influences consecutive to denervation.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone loss after cardiac transplantation: effects of calcium, calcidiol and monofluorophosphate

Of 203 patients who underwent cardiac transplantation and were given long-term treatment with cyclosporine and 0.3 mg/kg per day prednisone, 123 were studied prospectively for at least 6 months and 46 for up to 2 years to evaluate the effects on lumbar bone mineral density (BMD) and calcium metabolism of a combined therapy with calcium, calcidiol and disodium monofluorophosphate (MFP). The population was arbitrarily assigned to one of two groups. Group I consisted of patients who had a lumbar spine BMD Z score above -1.5 SD as compared with an age- and sex-matched population and no vertebral fractures. They received daily 1 g elemental calcium and 25 micrograms (1000 IU) calcidiol. Group II consisted of patients who received daily the same doses of calcium and calcidiol combined with 200 mg MFP, and was divided into two subgroups: (a) osteopenic subjects who had a lumbar spine BMD Z score below -1.5 SD without vertebral fractures and (b) osteoporotic subjects with vertebral fractures. If serum creatinine was higher than 140 mumol/l the daily dose of MFP was tapered to 100 mg. Fifty-four and 27 patients from group I and 38 and 19 patients from group II were followed respectively for 12 and 24 months. In both groups serum parathyroid hormone levels were significantly reduced from the twelfth month in parallel with a significant increase in serum 25-OHD levels. No decline in lumbar BMD occurred in non-osteopenic and non-osteoporotic patients (group 1) who received the calcium and calcidiol supplement. In group II, where MFP was added, a significant and linear increase in lumbar BMD was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative reduction of MTT by hearts biopsies in vitro is an index of viability

The aim of this study is to evaluate the use of tetrazolium reductase (TR) activity as an indicator of myocardial viability in an isolated arrested pig heart biopsy model. Methyl Tetrazolium (MTT) is cleaved by an enzyme in the presence of coenzymes NAD, NADP. Cleavage yields a highly colored formazan product which is DMSO soluble. Efficient bioreduction of MTT has been investigated with heart biopsies. The relationship between MTT reduction and (1) oxygen consumption (r = 0.96, P < 0.001), (2) the sum of the adenine nucleotide levels (r = 0.87, P < 0.001) and (3) localization of coloration, has been established. The use of MTT in colorimetric assays offers high sensitivity. MTT reduction is a valid method. It is rapid and reproducible, and can be used as an indicator of myocardial viability. The MTT test has been used to rapidly compare the effect of different cardioplegic solutions (St Thomas and improved St Thomas) on hypothermic cardiac preservation. Significant differences have been established between the two solutions (P < 0.01).

Primary cardiogenic shock during acute myocardial infarction: results of emergency cardiac transplantation

Fifteen patients with acute myocardial infarction and cardiogenic shock underwent emergency cardiac transplantation after medical treatment failed to improve their haemodynamic status. Their mean age was 49 +/- 7 years. The infarction was anterior in 12 cases, inferoposterior in two cases, and septal in one. Shock occurred within 3 days after the onset of chest pain in nine patients, and during the first day in six of them. Mechanical circulatory assistance was used in six patients as a bridge to transplantation when their haemodynamic status could not be stabilized pharmacologically. Orthotopic cardiac transplantation was performed an average of 15.6 +/- 14 days after onset of infarction. Three patients died during the early post-operative period. Another died 7 months after transplantation. During the mean follow-up period of 30.6 +/- 20.3 months, there were three acute rejections, all successfully treated, and one chronic rejection. The survival rate for this series is 70%. Thus, emergency cardiac transplantation may be the best option for selected patients with acute myocardial infarction and cardiogenic shock refractory to conventional therapy.

Comparison of continuous microperfusion and cold storage for pig heart preservation

The aim of this study was to compare two methods of hypothermic heart preservation. Isolated hearts of pigs were preserved in cold cardioplegic solution (St. Thomas Hospital solution) either by simple storage or continuous microperfusion (with a new perfusion device) for 6 hours (group I, n = 12), 12 hours (group II, n = 12) and 24 hours (group III, n = 12). After storage, the myocardial function was studied for 60 minutes under nonworking conditions with an ex vivo functional testing system. Hearts preserved 24 hours by cold storage (group III) showed ventricular compliance and mean spontaneous left ventricular developed pressure significantly lower than hearts preserved by microperfusion (respectively, 63 +/- 47 versus 14 +/- 18 mm Hg and 16.8 +/- 22.0 versus 83 +/- 33 mm Hg). After 12 hours (group II) of preservation, mean left ventricular developed pressure was higher in microperfused hearts compared to immersed hearts (respectively, 133.3 +/- 39.0 versus 83.1 +/- 27.0 mm Hg, p < 0.05), whereas after 6 hours of preservation, no functional difference was observed between the microperfused and the immersed hearts. Hearts were also studied using myocardial biopsy specimens taken at the end of the preservation. The biopsy specimens were analyzed for high-energy phosphates. After 6 hours of preservation, the microperfusion group showed higher levels of adenosine triphosphate and total adenine nucleotides (adenosine triphosphate + adenosine diphosphate + adenosine monophosphate) (respectively, 4.60 +/- 0.5 mumol/gm and 5.98 +/- 0.5 mumol/gm fresh tissue) versus the cold storage group (respectively, 3.10 +/- 0.4 mumol/gm and 3.75 +/- 0.4 mumol/gm).(ABSTRACT TRUNCATED AT 250 WORDS)

Lipid peroxides and antioxidant defenses in accelerated transplantation-associated coronary arteriosclerosis

Accelerated coronary artery disease develops in most if not all heart transplant recipients within the first year after transplantation. Increased lipid peroxidation seems to be involved in atherogenesis. In these patients we have investigated whether there is an association between lipid peroxidation, reduced antioxidant defenses, and some conventional coronary risk factors. Lipid peroxides, lipids, uric acid, albumin, antioxidant enzymes and their cofactors (the trace elements selenium, iron, copper, and zinc) have been determined in heart transplant recipients compared with nonrecipients with coronary artery disease. Lipid peroxides (p = 0.002) and uric acid (p = 0.01) were higher and zinc (p = 0.001) was lower in heart transplant recipients. Thirteen of 30 transplant recipients compared with one of 30 nonrecipients (p < 0.001) had very low (less than 10 mumol/L) zinc levels. Antioxidant enzymes and other trace elements were not significantly different. In univariate regression analysis, zinc correlated positively with albumin (p = 0.02) and negatively with lipid peroxides (p < 0.05). Uricemia had a strongly positive correlation with hydroperoxides (r = 0.45; p = 0.0001). In stepwise multivariate regression analysis, lipids, uricemia, creatinine, and zinc were significant (p < or = 0.004) predictors of the lipid peroxide level. Cyclosporine and corticosteroid dosages were significant (p = 0.01) determinants of zinc concentration in the transplant recipients. Although a causal relationship between increased lipid peroxidation and accelerated arteriosclerosis is not definitely demonstrated, the results of this analysis suggest new insights into conventional coronary disease risk factors and possible therapeutic interventions; further controlled trials are needed.

Accelerated coronary artery disease after heart transplantation: the role of enhanced platelet aggregation and thrombosis

The present study is a prospective examination of the relationship between platelet aggregation and the occurrence of graft failure in a single cohort of heart transplantation (HT) recipients. One-hundred-and-twenty-four patients underwent platelet function study and were then followed for 1 to 24 months (mean 6.7 months). There were nine re-transplantations and 13 deaths (11 related to ischaemic events, and two others). In 15 patients, pathologic examination confirmed or revealed that recent acute myocardial infarction was the obvious cause of the graft failure. In five patients, myocardial fibrosis related to severe and diffuse coronary disease was the only microscopic finding. In the last two patients, the cause of the heart failure was not clearly identified. In recent myocardial infarction there was a high incidence (14/15) of coronary thrombi. Thrombi were multiple, disseminated in the coronary tree end of different age. Their presence at autopsy or after explantation was associated with an enhanced ex vivo platelet aggregability as compared with patients without coronary thrombi (n = 8): 43.3 +/- 1.7% of maximal aggregation vs. 34.4 +/- 2.4 (P = 0.006) and 48.4 +/- 5.2 vs. 22.6 +/- 4.9 (P = 0.003) for the primary and secondary waves of ADP-induced aggregation. These results suggest that thrombosis and platelets may play a major role in the process of accelerated coronary artery disease after HT.

[Evaluation of non invasive methods for the diagnosis of atherosclerosis of the graft after orthotopic cardiac transplantation]

The frequency and severity of atherosclerosis of the cardiac transplant make it an essential complication of cardiac transplantation. Coronary angiography is the usual diagnostic method but it has severe limitations. In order to evaluate other diagnostic methods coronary angiography and non-invasive techniques: echocardiography, exercise stress ECG, exercise radionuclide ejection fraction, stress Thallium scintigraphy, were performed practically simultaneously in 60 patients after cardiac transplantation. These non-invasive methods were said to be positive in the presence of, respectively, a segmental wall motion abnormality, ischaemic ST segment depression, absence of increased ejection fraction on exercise, reversible or irreversible myocardial hypofixation. Coronary angiography was considered as the reference procedure for distinction between "normal coronary circulation" (no angiographically detectable lesion) and "graft atherosclerosis" (at least one coronary stenosis irrespective of the severity and extension). None of the non-invasive methods had an adequate sensibility when compared with coronary angiography (echocardiography 0.27, exercise stress ECG 0.28, exercise radionuclide ejection fraction 0.64, myocardial scintigraphy 0.62) or negative predictive value (echocardiography 0.56, exercise stress ECG 0.58, exercise radionuclide ejection fraction 0.68, myocardial scintigraphy 0.66). This inadequacy of the non-invasive technique may be explained by the fact that they are more adapted to the diagnosis of myocardial ischaemia than that of coronary studies. In addition, the extent of the coronary lesions may have masked discordance between 2 segments by the global hypovascularisation. The results of this study indicate that the non-invasive methods studied cannot be recommended for diagnosis of atherosclerosis of cardiac transplants.

[Cyclosporine. Obscure sides of cardiac and pulmonary transplantations]

Cyclosporine therapy after heart and lung transplantation implies a number of specific aspects such as: kidney deficiency associated to heart failure, which delays its use as for cardiac transplantation; intestinal absorption disturbances that could be linked to the cystic fibrosis disease for lung transplantation. For both types of transplantation, local efficiency could indicate an interesting, but still unexplored therapeutic effect. Finally, it seems that the immunosuppressive effect could be linked to important pharmacological effect on calcium and could explain the specific aspects of rejection of patients under cyclosporine.

[Chronic cardiac rejection. 20 anatomico-clinical cases]

Twenty anatomico-clinical cases of chronic cardiac rejection (accelerated coronary disease in heart transplant) consecutive to heart transplantation were studied with the view of obtaining detailed information on the anatomical features of coronary lesions, such as histopathological alterations, modalities of their diffusion to the 3 epicardial trunks and to distal intramyocardial branches, thrombotic complications and their consequences: massive (infarct) or disseminated myocardial ischaemia. The lesions observed were correlated with the corresponding coronary angiographic images, and an interpretation of the aetiopathological factors was attempted. Within a few months or years, the coronary lesions are found to progress towards very diffuse circumferential atherosclerous alterations where the plaques are clearly less individualized than in common atherosclerosis but thrombosis is frequent and multifocal in 50 percent of the cases. This produces a restrictive type of ischaemic cardiopathy which is painless since the heart is denervated, resulting in cardiac failure (11 cardiectomies for retransplantation, 9 autopsies) with coronary angiography tending to underestimate the importance of coronary damage. The most original aetiopathological factors seem to be arterial inflammation of immune origin, viral infections facilitated by immunosuppression and platelet hyperactivity, but their respective importance could not be accurately determined in this study.

Pharmacokinetics of cyclosporine in hyperlipidaemic long-term survivors of heart transplantation. Lack of interaction with the lipid-lowering agent, fenofibrate

Cyclosporine (Cy) binds to lipoproteins in plasma. In order to test if its pharmacokinetics would be modified when efficient lipid-lowering treatment is introduced, a study has been done of Cy pharmacokinetics and any interaction with the lipid-lowering agent fenofibrate in hyperlipidaemic long-term, survivors of heart transplantation. Fenofibrate 200 mg once daily significantly reduced blood lipids (cholesterol 6.5 vs 7.7 mmol/l; apoprotein B 1.2 vs 1.6 g/l) but did not modify mean whole blood Cy trough levels (113 before fenofibrate vs 103 ng.ml-1), Cmax (812 ng.ml-1 by RIA and 757 ng.ml-1 by HPLC before fenofibrate versus 865 and 741 respectively, during fenofibrate); tmax (1.6 and 1.7 h before fenofibrate versus 1.4 and 1.4 h respectively), and t1/2 (13.9 and 11.1 h versus 9.5 and 10.7 h). The only adverse effect was an increase in creatinine (157 vs 145 mmol/l). Further studies are needed to investigate the mechanism of Cy-fenofibrate nephrotoxicity and to evaluate the long-term efficiency and safety of fenofibrate after heart transplantation.

Platelet function and composition in heart transplant recipients compared with nontransplanted coronary patients

Accelerated coronary artery disease seems to be the main condition limiting long-term survival after heart transplantation. Ninety-one heart transplant recipients were compared with 94 nontransplanted coronary artery disease patients in an attempt to identify the factors responsible for the accelerated form of coronary artery disease occurring after heart transplantation. Among the parameters examined, heart transplant recipients exhibited a higher plasma level of insulin (8.5 +/- 0.5 versus 6.2 +/- 0.3 mIU/l, p = 0.002), a lower plasma level of vitamin E (14.8 +/- 0.4 versus 16.9 +/- 0.7 mg/l, p = 0.03), a higher platelet cholesterol-to-phospholipid ratio (8.9 +/- 0.3 versus 7.6 +/- 0.3, p = 0.007), and an increased response to ADP-induced platelet aggregation (for the first wave, 29.1 +/- 0.9% of maximal aggregation versus 25.1 +/- 1.0%, p = 0.002; for the second wave, 21.4 +/- 1.4% versus 15.9 +/- 1.1%, p = 0.002, after adjustment for hematocrit), but no untoward changes in the level of fibrinogen, plasminogen activator inhibitor-1, antithrombin III, or lipoprotein(a). In addition, platelet aggregation in patients who required retransplantation as a result of severe coronary artery disease was similar before and after retransplantation. This suggests that severe coronary artery disease is not the cause of platelet hyperaggregability. In multiple-regression analysis, ADP-induced platelet aggregation in heart transplant recipients was significantly positively related to blood glucose (r = 0.50, p less than 0.001) and inversely related to n-3 fatty acids from platelet phospholipids (r = 0.40, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)