Frequency of hypercholesterolemia after cardiac transplantation

Early Rejection of Human Cardiac Allografts Is a Risk Factor for Multiple Rejection Episodes

To determine the risk factors associated with development of acute cardiac allograft rejection during the first 3 months after transplant, data from 1,552 endomyocardial biopsies from 122 cardiac transplant recipients receiving their first graft were analyzed. An association (P< .0001) between the onset of a first rejection episode and the frequency of rejection episodes in the first 90 days was established. Our findings suggest that patients presenting with an early onset of first cardiac allograft rejection episode are at risk for multiple rejection episodes and should therefore be more closely monitored. Int J Surg Pathol 3(I):9-16, 1995

Long-term dietary habits and interventions in solid-organ transplantation

Diet and nutrition are moving to the forefront of modern primary and preventive care to help address the rising burden of chronic diseases among the general population. Such a movement has yet to occur formally across the field of transplantation. We therefore looked to establish the current base of knowledge regarding diet, nutrition and solid-organ transplantation. A limited number of focused studies looking into the dietary habits of solid-organ transplant patients have been performed and many of the available studies have detailed the nutritional status in the peri-operative period. Frequently described, however, is the heavy incidence of metabolic abnormalities, such as obesity, dyslipidemia and diabetes, occurring after solid-organ transplantation. Optimistically, several studies have noted improvement in several metabolic abnormalities with the use of dietary interventions in the post-transplant period. Despite these positive results, few consensus guidelines for post-transplant diet have been established and nutritional support among transplant programs remains limited. Although there are many hurdles to implementation of detailed dietary recommendations and nutritional support for transplant patients, creating such programs and guidelines could dramatically impact long-term outcomes and burden of chronic metabolic disease for transplant recipients.

Systemic immunosuppressive therapy inhibits in-stent restenosis in patients with renal allograft

BACKGROUND

Cyclosporine is used routinely for prophylaxis for renal allograft rejection. In experimental animal studies, cyclosporine had been shown to inhibit smooth muscle cell proliferation during the arterial response to injury. We investigated whether systemic immunosuppression may inhibit in-stent restenosis in renal transplant patients undergoing coronary stenting.

METHODS

From 1993 to 2003, 33 renal transplant patients with 45 coronary lesions and 37 dialysis patients with 52 lesions underwent coronary stenting using bare metal stents at our center. We followed all patients clinically for a mean period of 37 +/- 31 months and 40 patients angiographically at 14 +/- 15 months after coronary intervention. Cyclosporine was combined with corticosteroids in 32 patients and one patient received tacrolimus instead of cyclosporine.

RESULTS

The baseline clinical and angiographical characteristics were similar and the success rate of the procedure was 100% in both groups. In renal transplant group, the mean dose of cyclosporine was 192.5 +/- 68 mg/day and the blood cyclosporine level at the time of procedure was 152.9 +/- 51.5 ng/mL. The rate of in-stent restenosis was 7.1% in renal transplant group and 57.1% in dialysis group (P < 0.0001). The mean late loss was 0.47 +/- 0.57 mm in renal transplant group when compared with 1.51 +/- 1.09 mm in dialysis group (P = 0.004). The overall rate of major adverse cardiac events (MACEs) was 6.1% in renal transplant group and 35.1% in dialysis group (P < 0.0001).

CONCLUSIONS

Renal transplant patients receiving combined immunosuppressive agents showed markedly low rates of in-stent restenosis and MACE after coronary revascularization with stent. We consider that this result may be related to the ability of combined immunosuppressive therapy to inhibit inflammatory reaction and vascular smooth muscle cell proliferation induced by coronary stenting.

Plasma kinetics of a cholesterol-rich microemulsion in patients submitted to heart transplantation

BACKGROUND

Development of coronary graft disease is currently the main cause of late heart-transplantation (HT) failure. HT patients frequently show hypercholesterolemia as well as alterations in chylomicron metabolism. These postHT changes may be important in coronary graft disease development. To clarify whether hypercholesterolemia is caused by decreased low-density lipoprotein (LDL) removal from the plasma, we studied the plasma kinetics of a cholesterol-rich emulsion that binds to LDL receptor.

METHODS

We studied 13 HT patients and 13 healthy normolipidemic subjects paired for sex, age, and body mass index. An emulsion labeled with C-cholesteryl oleate was injected intravenously, and blood samples were collected in predetermined intervals (5 minutes, 1, 2, 4, 6, and 8 hours) to determine the radioactivity decay curves and to calculate the fractional clearance rates (FCR).

RESULTS

The plasma level of total cholesterol, LDL cholesterol, high-density lipoprotein cholesterol, and apo B were greater in HT group than in the control group (P<0.005). FCR C-cholesteryl oleate was smaller in HT patients when compared with the control group (P=0.02).

CONCLUSION

The results showed that HT patients have a deficiency in the mechanisms of LDL removal from the plasma, as tested by the cholesterol-rich emulsion, and this may be important in the development of coronary graft disease.

Treatment of hyperlipidemia in cardiac transplant recipients

Of the 60,000 patients receiving heart transplants between 1982 and 2001, approximately 12,000 are currently alive. The high incidence of hyperlipidemia and coronary disease (also known as accelerated graft atherosclerosis, or AGA) in these patients warrants early prophylaxis soon after transplantation with 3-hydroxy-3-methylglutaryl (HMG) Co-A reductase inhibitors (statins). Immunosuppressive agents such as prednisone, cyclosporine, mycophenylate mofetil, and sirolimus are associated with hyperlipidemia. Statins, in addition to lowering cholesterol levels, also benefit cardiac transplant recipients via effects on the immune system and endothelial function. Recent data have demonstrated that statins decrease AGA and mortality rates. Furthermore, greater benefits are seen when statins are started early. The 2 statins shown to decrease mortality in patients after cardiac transplantation are pravastatin and simvastatin, which differ in their metabolism (pravastatin is the only statin with non-cytochrome metabolism) and lipophilicity (pravastatin is less lipophilic). Although the benefit of simvastatin has been shown to extend to 8 years after transplantation, increased adverse effects in other studies with higher doses of simvastatin have resulted in new prescribing recommendations, which state that the dose of simvastatin should probably not exceed 10 mg with cyclosporine or gemfibrozil and 20 mg with amiodarone or verapamil. The evidence for potential benefits, interactions, and adverse effects of other potential lipid-lowering drugs for this patient population, such as fibrates, niacin, fish oil, cholestyramine, and ezetimibe, are also discussed. A summary algorithm is proposed, including approaches to patients with statin-associated musculoskeletal symptoms and patients with inadequate results after initial statin therapy.

Immunosuppression and transplant vascular disease: benefits and adverse effects

Cardiac allograft vasculopathy (CAV) occurs within 5 years of transplantation surgery and represents the main cause of death in long-term heart transplant survivors. The detailed pathogenesis of CAV is unknown, but there are strong indications that immunologic mechanisms, which are regulated by nonimmunologic factors, are the major cause of this phenomenon. Cyclosporine A (CsA) is a frequently used immunosuppressive agent in transplant medicine to prevent rejection. The mechanism of action of CsA involves initial binding to cyclophilin to form a complex that then inhibits calcineurin (CN), leading to reduced interleukin (IL)-2 production as part of the signal transduction pathway for the activation of B-lymphocytes and T-lymphocytes. Based on this proposed mechanism, it was expected that CsA should be an effective strategy in attenuating the host immune response against transplanted allograft tissue; however, CsA has not changed the outcome of CAV. Several mechanisms have been suggested for the ineffectiveness of CsA in long-term prevention of CAV. For example, routine therapeutic doses of CsA may block CN incompletely (50%), whereas complete blockade requires doses that are not clinically tolerable. Another explanation is the possible activation of T-cell receptors directly (CN independent) by the immune response, which induces protein kinase C theta (PKCtheta) and leads to IL-2 production and immune rejection. Moreover, there may be a role for nonimmunologic mechanisms, such as complement, which cannot be controlled by CsA, or CsA may cause hypercholesterolemia or induce overexpression of transforming growth factor-beta (TGF-beta). This review also compares the effect of CsA with other immunosuppressants in allograft artery preservation and their clinical efficacy.

Are Cardiovascular Disease and Osteoporosis Directly Linked?

For years, osteoporosis and cardiovascular disease were thought to be two independent consequences of aging; however, mounting evidence supports an association between these diseases. Recently, a widespread class of cholesterol-lowering drugs known as statins have demonstrated (in rodents and cell cultures) the ability to induce bone formation. This finding is significant since current therapies are limited to the prevention or slowing down of bone loss rather than (enhancing/improving) bone formation. In humans, the ability of statins to generate new bone has not been consistent; however, several investigations have demonstrated a dramatic decrease in fracture risk. Although it has been proposed that statins induce new bone via increased bone morphogenetic protein-2, other conditions affected by statins such as dyslipidaemia, vascular calcification, endothelial dysfunction and impaired nitric oxide expression, may also contribute to the cardiovascular and bone health paradigm. Furthermore, the role of physical activity and its influence on cardiovascular and bone health, especially in postmenopausal women, may contribute to the discrepancy of findings in human data. In summary, it remains to be determined if statins contribute to bone health via improvements in vascular health or by pleiotropic properties unique to their pharmacology. This review provides information on our current understanding of the bone and cardiovascular association, as well as on novel areas of research to further our current understanding of these conditions.

Inhibiting the NO pathway with intracoronary L-NAME infusion increases endothelial dysfunction and intimal hyperplasia after heart transplantation

BACKGROUND

The endothelium protects the vascular wall through the nitric oxide (NO) release. Coronary endothelial dysfunction occurs early after heart transplantation and predicts the development of intimal thickening typical of graft coronary vasculopathy.

OBJECTIVE

We designed this study to examine the effect of endothelial NO synthase (eNOS) inhibition on the endothelial dysfunction caused by rejection and on the development of accelerated atherosclerosis after heart transplantation.

METHODS

To study the effect on these 2 end-points of inhibiting eNOS with intracoronary L-nitro arginine methyl ester (L-NAME; 1 mg/kg/day), infused with an osmotic pump for 30 days, we used a porcine model of heterotopic heart transplantation with pre-operative immunologic typing, to permit slow rejection without the need for immunosuppression. The endothelium-dependent relaxations of allografted coronary arteries, allografted arteries infused with L-NAME, allografted arteries mounted with the pump, and vehicle and native coronary arteries were compared 30 days after graft implantation using standard organ chamber experiments. We evaluated intimal thickening using a semi-quantitative scale (0-4+ grading).

RESULTS

A significant decrease in relaxations to serotonin (5-HT) occurred in allografted arteries infused directly with L-NAME compared with allografted arteries from swine receiving 5-HT, and relaxations in the latter were decreased compared with those of swine receiving the vehicle and native coronary arteries (p < 0.05). We found no significant differences in endothelium-dependent relaxations to bradykinin among coronary rings from all groups. We observed a significant increase in the prevalence and severity of intimal thickening in allografted coronary arteries infused with L-NAME compared with allografts not infused (p < 0.05), which had significantly more intimal thickening compared with native coronary arteries (p < 0.05).

CONCLUSION

These results demonstrate that inhibiting the NO pathway worsens the endothelial dysfunction caused by rejection after heart transplantation and accelerates the intimal thickening process, leading to graft coronary vasculopathy. Strategies designed to preserve endothelial integrity and function of the endothelial NO pathway should be used to prevent graft coronary vasculopathy.

The apo A-I gene promoter region polymorphism determines the severity of hyperlipidemia after heart transplantation

BACKGROUND

To study whether the Apolipoprotein A-I (apo A-I) promoter region gene polymorphism produces changes in the lipid profile of heart transplant recipients.

METHODS

One hundred and three heart transplant recipients (93 men and 10 women, with a mean age of 47 +/- 13 yr) receiving triple immunosuppressive therapy were submitted to a genetic study of the apo A-I gene promoter region. Anthropometric and analytical data, including lipid profile, arterial blood pressure, were collected prior to transplantation and 3, 6, 12, and 24 months after transplantation.

RESULTS

Sixty-three subjects had the GG genotype and 40 the GA genotype. Carriers of the GA genotype had higher triglyceride levels at 6 months and 2 yr (2.50 +/- 1.20 versus 1.93 +/- 0.98 mmol/L and 2.46 +/- 1.58 versus 1.60 +/- 0.68 mmol/L, respectively, p < 0.001), and a greater rise in LDL-cholesterol at 1 yr than the GG subjects (4.57 +/- 1.16 versus 4.16 +/- 1.18 mmol/L, p < 0.05). Multiple regression analyses showed that genetic variants at the apo A-I promoter region are responsible for 11% of the variability in triglyceride levels at 6 months (p = 0.005).

CONCLUSIONS

The GA genotype of the apo A-I promoter region produces a greater rise in plasma triglyceride and LDL-cholesterol levels in heart transplant patients.

Safety and efficacy of pravastatin therapy for the prevention of hyperlipidemia in pediatric and adolescent cardiac transplant recipients

BACKGROUND

Hyperlipidemia is common after cardiac transplantation and it is a risk factor for post-transplantation coronary artery disease. Immunosuppression with corticosteroids and cyclosporine has been associated with hyperlipidemia. Pravastatin, a HMG-CoA reductase inhibitor, has been shown to be effective and safe for cholesterol reduction in adult heart transplant recipients. To our knowledge the safety and efficacy of pravastatin therapy in pediatric and adolescent heart transplant populations have not been previously analyzed. Therefore, we evaluated lipid profiles, liver transaminases, rejection data, and possible side effects in pediatric and adolescent cardiac transplant recipients treated with pravastatin.

METHODS

The study group consisted of 40 cardiac transplant recipients 10 to 21 years old (mean age 16.9 years). Twenty-two patients received pravastatin in addition to an immunosuppressive regimen of either cyclosporine or tacrolimus, azathioprine or mycophenolate mofetil, and prednisone. Serial determinations of total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein, and triglycerides were available for all pravastatin-treated patients. Pre-treatment lipid values and hepatic transaminases were compared with those measured after therapy with pravastatin. Comparison of pravastatin-induced lipid reduction between groups treated with cyclosporine vs tacrolimus was also made.

RESULTS

Patients receiving pravastatin experienced a mean 32 mg/dl decrease in TC (p < 0.005) and a mean 31 mg/dl decrease in LDL (p < 0.005), regardless of their immunosuppressive regimen. No statistical differences occurred in the magnitude of mean lipid reduction induced by pravastatin between the groups treated with cyclosporine vs tacrolimus. No significant changes in hepatic transaminase levels were noted, and no clinical evidence of pravastatin-induced myositis occurred in any subjects.

CONCLUSION

Pravastatin therapy is effective and safe when used in pediatric and adolescent cardiac transplant recipients. Although the pravastatin-induced reduction in TC and LDL was more pronounced in patients receiving cyclosporine, the reduction was not statistically different from that in the tacrolimus group. No evidence of hepatic dysfunction or rhabdomyolysis in patients treated with pravastatin was noted. Long-term studies are required to evaluate the effect of pravastatin therapy on the incidence of accelerated coronary atherosclerosis in this population.

Cardiac allograft vasculopathy

Cardiac transplantation has emerged as a valuable therapy for various end-stage cardiac disorders. Cardiac allograft vasculopathy (CAV), an unusually accelerated and diffuse form of obliterative coronary arteriosclerosis, determines long-term function of the transplanted heart. Cardiac allograft vasculopathy is a complicated interplay between immunologic and nonimmunologic factors resulting in repetitive vascular injury and a localized sustained inflammatory response. Dyslipidemia, oxidant stress, immunosuppressive drugs, and viral infection appear to be important contributors to disease development. Endothelial dysfunction is an early feature of CAV and progresses over time after transplantation. Early identification of CAV is essential if long-term prognosis is to be improved. Annual coronary angiography is performed for diagnostic and surveillance purposes. Intravascular ultrasound is a more sensitive diagnostic tool for early disease stages and has revealed that progressive luminal narrowing in CAV is in part due to negative vascular remodeling. Because of the diffuse nature of CAV, percutaneous and surgical revascularization procedures have a limited role. Prevention of CAV progression is a primary therapeutic goal.

Genetic variations of the apolipoprotein E gene determine the plasma triglyceride levels after heart transplantation

OBJECTIVES

To study whether the presence of the polymorphism in the apolipoprotein E (apo E) gene influences the lipid profile in heart-transplant recipients.

METHODS

A cohort of 103 recipients of heart transplant (93 men and 10 women, with a mean age of 47 +/- 13 years) under triple immunosuppressive therapy were submitted to a genetic study of the apo E gene region. Anthropometric and analytical data, including lipid profile and arterial blood pressure were collected prior to transplantation and 3, 6, 12, and 24 months after it.

RESULTS

65 subjects present the genotype E3E3, 27 the genotype E3E4, 6 the genotype E2E3, and 5 the genotype E2E4. Carriers of the E2 allele (that is, genotypes E3E2 and E4E2) had higher total plasma triglyceride (TG) levels after 3 months (3.47 +/- 1.88 mmol/liter p < 0.001) and after 1 year of transplantation (3.13 +/- 1.77 mmol/liter p < 0.05) than the other genotypes. There were no differences in the plasma levels of total cholesterol (TC), LDL-cholesterol (LDL-C), and HDL-cholesterol (HDL-C). Multiple regression analysis revealed that the apoprotein E gene polymorphism determines 5% (p = 0.0425) and age 8.7% (p < 0.009) of the variants in TG levels.

CONCLUSIONS

The presence of the E2 allele in heart-transplant recipients produces a greater rise in total TG plasma levels than the other genotypes.

Hypercholesterolemia increases coronary endothelial dysfunction, lipid content, and accelerated atherosclerosis after heart transplantation

Hyperlipidemia may increase endothelial damage and promote accelerated atherogenesis in graft coronary vasculopathy. To study the effects of hypercholesterolemia on coronary endothelial dysfunction, intimal hyperplasia, and lipid content, a porcine model of heterotopic heart transplantation, allowing nonacute rejection without immunosuppressive drugs, was used. A high cholesterol diet was fed to donor and recipient swine 1 month before and after transplantation. The endothelial function of coronary arteries of native and transplanted hearts from cholesterol-fed animals was studied in organ chambers 30 days after implantation and compared with endothelial function in arteries from animals fed a normal diet. The total serum cholesterol increased 3-fold in donors and recipients. Endothelium-dependent relaxations to serotonin, to the alpha(2)-adrenergic agonist UK14,304, and to the direct G-protein activator sodium fluoride were decreased significantly in allografted hearts compared with native hearts from both groups. Relaxations to the calcium ionophore A23187 and bradykinin were decreased significantly in allografts from animals fed the high cholesterol diet. The prevalence of intimal hyperplasia was significantly increased in coronary arteries from hypercholesterolemic swine. There was a significant increase in the lipid content of allograft arteries of hypercholesterolemic recipients. Hypercholesterolemia causes a general coronary endothelial dysfunction, increases the prevalence of intimal hyperplasia, and augments the incorporation of lipids in the vascular wall after heart transplantation. Hyperlipidemia accelerates graft coronary atherosclerosis through its effects on the endothelium.

Tacrolimus-based triple-drug immunosuppression minimizes serum lipid elevations in pediatric cardiac transplant recipients

BACKGROUND

Immunosuppression with corticosteroids and cyclosporine has been associated with hyperlipidemia, a risk factor for post-transplant coronary artery disease. The recent development of tacrolimus has created an alternative to cyclosporine-based triple drug immunotherapy. One potential benefit that has been reported in patients receiving tacrolimus is a minimization of elevation of both total and LDL cholesterol, compared to those increases observed in patients receiving cyclosporine-based immunosuppression. It is unclear in previous studies whether this beneficial effect is related to tacrolimus directly or to its corticosteroid sparing potential. To study this relationship, we compared lipid profiles from pediatric cardiac transplant recipients treated with corticosteroids, and either cyclosporine or tacrolimus.

METHODS

The study group consisted of 23 patients (mean age = 12.3 years) with pre-transplant and serial post-transplant determinations of total cholesterol, LDL, HDL, and triglycerides. Patients were separated into 4 study groups, defined by immunosuppressive regimen (cyclosporine vs. tacrolimus) and prednisone dose (>0.10 mg/kg/day vs. < or =0.10 mg/kg/day).

RESULTS

Patients who received cyclosporine and higher doses of prednisone experienced a mean 74 mg/dl increase from baseline in total cholesterol (p = .0001). None of the other 3 treatment groups demonstrated a statistically significant elevation. Similar trends were observed in LDL and triglyceride alterations between the 4 study groups. Interestingly, patients treated with tacrolimus and higher doses of prednisone demonstrated a significant rise in HDL from baseline (p = .0001), although those who received cyclosporine and higher dose prednisone failed to exhibit this rise.

CONCLUSION

The minimal degree of lipid alteration seen in patients receiving tacrolimus and higher doses of prednisone indicates that this effect was not solely based upon the steroid-sparing properties of tacrolimus therapy. The data also suggests a possible synergistic effect between cyclosporine and higher doses of prednisone on hyperlipidemia. Therefore, in pediatric patients requiring higher corticosteroid doses late after transplantation, use of tacrolimus rather than cyclosporine may lead to more favorable lipid profiles and help minimize the risk of post-transplant coronary arteriopathy.

Heart allograft vascular disease: an obliterative vascular disease in transplanted hearts

More than 30 years have passed since the first human heart transplantation was performed. Since then, short-term survival after heart transplantation has been markedly improved, but this development has not been paralleled with a similar improvement in long-term survival. One of the major reasons for this is the subsequent development of heart allograft vascular disease, an obliterative disease in the coronary arteries of the transplanted heart. The dubious effect of re-vascularization in this disease, the less favorable outcome after repeat heart transplantation, and the low donor supply have called for intensified research for new and efficient prophylactic therapies against heart allograft vascular disease. This research has lead to improved knowledge about diagnosis, etiology, pathogenesis, prophylaxis, and treatment possibilities. The most important among these seem to be: (i) the introduction of intravascular ultrasound for early detection of the disease; (ii) evidence to suggest that hyperlipidemia, insufficient immunosuppressive therapy, human leukocyte antigen (HLA)-mismatch, and infection with cytomegalovirus (CMV) all may promote allografts vascular disease; and (iii) the introduction of at least two promising prophylactic therapies in humans namely 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors and calcium entry blockers, and others potentially promising e.g. angiotensin-converting enzyme-inhibitors, angiopeptin, mycophenolate mofetil and rapamycin. This review summarizes present knowledge on the possibilities of inhibiting or treating heart allograft vascular disease incorporating evidence from both human and experimental studies.

Obesity and hypercholesterolemia following heart transplantation

Successful strategies for avoiding obesity and hypercholesterolemia are difficult to validate because of imprecise problem identification. The purpose of this study was to describe the incidence, severity, and onset of obesity and hypercholesterolemia among heart transplant recipients and identify relationships between demographic variables and weight or cholesterol levels during the first year following transplantation. Data were collected from retrospective chart review. Forty-two patients were randomly selected from 224 patients who were undergoing heart transplantation at the Johns Hopkins Hospital between July 1983 and December 1995. Significant differences were found in weight and cholesterol level during the first 12 months. Patients with ideal body weight less than 110%, compared with greater than 110%, survived longer. Relationships were identified between prednisone dose and weight, cumulative prednisone dose and weight, and weight change and change in total cholesterol level 1 year following transplantation. Multivariate analysis showed cumulative prednisone as an independent predictor of weight. Obesity and hypercholesterolemia were significant problems within 3 months of transplantation. Although prednisone dosage should be adjusted to the lowest possible dose, dietary and lifestyle changes remain the foundation of effective management of these posttransplant complications.

Influence of FK506 on experimental atherosclerosis in cholesterol-fed rabbits

To investigate the role of activated T lymphocytes in the formation of atherosclerotic lesions, we studied the influence of FK506, an immunosuppressant, on the development of atherosclerosis in cholesterol-fed rabbits. New Zealand White rabbits fed on a 1.5% cholesterol diet were administered FK506 at 0.05 mg/kg (n = 12), 0.1 mg/kg (n = 12) or isotonic saline (as the control, n = 12) intramuscularly three times a week for 12 weeks. Although FK506 treatment did not affect plasma lipid levels, it caused an increase in the development of atherosclerotic lesions in a dose-dependent manner. Immunohistochemical analysis of the aorta after 8 weeks on the diet revealed that the ratio of T lymphocytes to the total number of cells in the plaques decreased significantly in the FK506 treated rabbits compared to the control rabbits. In culture, FK506 did not affect smooth muscle cell proliferation and cholesteryl ester formation in the macrophages. In contrast, culture medium from lymphocytes stimulated by concanavalin A decreased the accumulation of cholesteryl ester in the macrophages. This effect was inhibited by the culture medium in the presence of FK506. These findings suggest that activated T lymphocytes may inhibit intracellular cholesterol accumulation in atherosclerotic plaque.

Post-transplant hyperlipidaemia: low-dose lovastatin lowers atherogenic lipids without plasma accumulation of lovastatin

OBJECTIVES

The purpose of the present study was twofold. First, to determine the frequency of hyperlipidaemia after heart transplantation (Tx) in relation to values obtained before Tx. Secondly, to examine the effect of low-dose lovastatin on possible antiatherogenic mechanisms and test the hypothesis that the side-effects are dose-dependent.

SUBJECTS AND DESIGN

Retrospective study of the frequency of hyperlipidaemia disturbances in heart transplant patients. In addition, in a prospective study, the safety and efficacy of incremental low doses of lovastatin up to 20 mg day-1 were studied, with measurements of its plasma concentration in 24 cyclosporin A treated heart (n = 14) and kidney (n = 10) recipients with total cholesterol > 7.5 mmol L-1.

RESULTS

Cholesterol increased markedly after heart transplantation from a pretransplant value of 5.3 (5.0,5.6) mmol L-1 to 6.7 (6.4,7.0) mmol L-1 after 1 year and then remained constant, but this increase was largely due to a 'normalization' since cholesterol decreased significantly during increasing heart failure before transplantation. Treatment with lovastatin decreased total cholesterol by 19% (P < 0.001), primarily by an effect on LDL cholesterol. HDL cholesterol increased by 15% (P < 0.05), whereas triglycerides remained unchanged. Lovastatin also caused a significant reduction in apolipoprotein B of 16%, and lipid peroxidation of 40%, whereas apolipoprotein A-I, fibrinogen, and glycerol were unchanged. Plasma concentration of lovastatin was significantly higher in transplant recipients compared with controls, but there was no accumulation during incremental dosing of lovastatin. The drug was well tolerated without significant symptoms or evidence of myopathy.

CONCLUSIONS

Hyperlipidaemia is common after cardiac transplantation. Treatment with low dose lovastatin is well tolerated and has a favourable effect on atherogenic lipids.

Management of the cardiac transplant recipient: roles of the transplant cardiologist and primary care physician

Cardiac transplantation has become an accepted treatment for selected patients with end-stage heart failure. Despite a successful transplant, denervated transplanted hearts respond differently to cardiac drugs than nontransplanted hearts. The treatments for bradycardia, tachycardia, and hypotension are different than for nontransplanted hearts. Despite the improvement in long-term survival, a number of complications may occur posttransplantation. These complications include, allograft rejection, infection, allograft coronary artery disease, and malignancy. Additionally, posttransplant patients may have complications from the immunosuppressive agents cyclosporine, prednisione, and azathioprine. Such complications include drug interactions with commonly prescribed medications, hypertension, hyperlipidemia, osteoporosis, and gastrointestinal complications. The purpose of this article is to discuss the management of the cardiac transplant recipient as it relates to the aforementioned complications. Management of the cardiac transplantation patient by the primary care physician will also be discussed, including indications for consultation by the primary care physician with the transplant center.

Long-term survivors of pediatric heart transplantation: a multicenter report of sixty-eight children who have survived longer than five years

OBJECTIVE

Short-term survival after pediatric heart transplantation is now excellent, but ultimately the efficacy of this procedure will depend on duration and quality of survival. We sought to evaluate the clinical course of long-term survivors of heart transplantation in childhood.

METHODS

Patients who had undergone heart transplantation at the university hospitals of Stanford, Columbia, and Pittsburgh between 1975 and 1989 and survived longer than 5 years from transplantation were identified and their clinical courses retrospectively reviewed.

RESULTS

Sixty eight children have survived more than 5 years from transplantation, and 60 (88%) are currently alive with a median follow-up of 6.8 years (5 to 17.9 years). Thirteen have survived more than 10 years from transplantation. Renal dysfunction caused by immunosuppressive agents was common, and two patients required late renal transplantation. Lymphoproliferative disease or other neoplasm occurred in 12 patients, but none resulted in death. Coronary artery disease was diagnosed in 13 patients (19%), leading to retransplantation in eight. Death after 5 years was related to acute or chronic rejection in 5 of 8 cases. Two of the deaths were directly related to noncompliance with immunosuppressive medication. All survivors are in New York Heart Association class 1.

CONCLUSIONS

Long-term survival with good quality of life can be achieved after heart transplantation in childhood, though complications of immunosuppression remain common. Posttransplantation coronary artery disease is emerging as the main factor limiting long term graft and patient survival.

The use of HMG-CoA reductase inhibitors to prevent accelerated graft atherosclerosis in heart transplant patients

Initial trials hint that HMG-CoA reductase inhibitors may have a role in preventing or retarding the progression of AGAS. Whether the potential of HMG-CoA reductase inhibitors to prevent AGAS is due to their lipid-lowering effect, immunomodulating properties, or a combination of both is also not completely known at present. Further study is needed to fully identify their mode of preventing AGAS and, more important, to determine their usefulness and role in preventing AGAS, especially since concurrent HMG-CoA reductase inhibitor use with cyclosporine is not innocuous. Potential for a pharmacokinetic drug interaction, which results in an elevation of HMG-CoA reductase inhibitor concentrations, exists when these two agents are used together, thus increasing the potential for the HMG-CoA reductase inhibitor to cause musculoskeletal complications. When such combination therapy is used, the likelihood of this interaction can be reduced by prescribing the HMG-CoA reductase inhibitor conservatively--using the smallest effective dose and increasing the daily dosage slowly. Although the risk of musculoskeletal toxicity exists at any HMG-CoA reductase inhibitor dosage, most patients should be able to tolerate daily dosages of up to 20 mg of lovastatin, 10 mg of simvastatin, and 40 mg of pravastatin. Patients also need to be made aware of and monitored for musculoskeletal symptoms suggestive of myositis and/or myalgias. In addition, the avoidance of elevated cyclosporine concentrations and when practical, monitoring of HMG-CoA reductase inhibitor concentrations are recommended.

Cyclosporin A trough levels correlate with serum lipoproteins and apolipoproteins: implications for therapeutic drug monitoring of cyclosporin A

In a prospective study over 6 months, the relationship between serum lipid parameters and CsA whole blood trough concentrations was investigated in 39 renal transplant recipients receiving a triple immunosuppressive therapy with cyclosporin (CsA), azathioprine and prednisone. CsA trough concentrations were measured with a selective monoclonal immunoassay (Abbott TDx). Six months after transplantation, significant positive correlations were observed between the CsA trough concentration and serum concentrations of triglycerides (r = 0.448, p < 0.01), total cholesterol (r = 0.360, p < 0.05), and apoB (r = 0.418, p < 0.01). After exclusion of patients with over hypertriglyceridemia (> 400 mg/dl), however, the associations were no longer significant. HDL-cholesterol (HDL-C) and apo AI concentrations showed significant inverse correlations with the CsA trough level (HDL-C: r = -0.427, p < 0.01; apoAI: r = -0.350, p < 0.05); the correlations with the CsA trough level were still significant (HDL-C: r = -0.379, p < 0.05; apoAI: r = -0.354, p < 0.05) after exclusion of patients with triglyceride levels of > 400 mg/dl. As a result of these divergent effects on the plasma lipids and lipoproteins, there was a strong positive association (r = 0.633, p < 0.001) between the CsA trough concentration and the total cholesterol/HDL-C ratio. Consequently, elevated total cholesterol/HDL-C ratios that represent an increased atherogenic risk tended to be associated with higher CsA trough levels. In monitoring CsA therapy of renal transplant recipients on maintenance immunosuppressive therapy, it may well be advisable to adjust CsA dosages to obtain CsA trough levels within the lower therapeutic range for patients with an unfavorably high TC/HDL-C ratio.

Risk factors for premature coronary heart disease after successful liver transplantation in adults

As solid-organ transplantation has evolved into a highly effective treatment for end-stage organ disease, the long-term health implications of chronic exposure of recipients to immunosuppressants and other pharmacological agents are becoming more apparent. Coronary heart disease has long been known to plague kidney transplant recipients and more recently has been found to affect heart transplant recipients disproportionately. Coronary heart disease after liver transplantation, however, is less well known. The purpose of this study was to examine risk factors for premature coronary heart disease in asymptomatic adult recipients of liver transplants. Nutrition-related risk factors for coronary heart disease (obesity and hyperlipidemia) were measured in 29 patients before and after liver transplantation. Changes with respect to primary immunosuppression protocol (cyclosporine plus corticosteroid vs tacrolimus plus corticosteroid) were compared. Risk factors that had not been present before transplantation were apparent in both groups by 6 months after transplantation. Although obesity and hyperlipidemia were not found to be independent risk factors for coronary heart disease, they were clinically important when considered in combination. Cyclosporine was associated with significantly higher serum lipid concentrations than was tacrolimus.

Coronary artery intimal thickening in the transplanted heart. An in vivo intracoronary untrasound study of immunologic and metabolic risk factors

This study examined the hypothesis that immunologic factors are the major correlates of coronary artery intimal thickening and luminal stenosis. The study population included 116 adult heart transplant recipients with a mean age of 44.7 +/- 12.0 years (89 men and 27 women) undergoing annual coronary angiography and intracoronary ultrasound 3.4 +/- 2.7 (range, 1.0-14.6) years after transplantation. Mean intimal thickness was obtained from several distinct sites along the left anterior descending and/or left circumflex coronary artery by intracoronary ultrasound. Coronary artery stenosis defined by angiography was classified as mild (< 30% luminal stenosis), moderate (> or = 30-70% luminal stenosis), or severe (> 70% luminal stenosis or diffuse pruning of distal vessels). Prevalence of any transplant coronary artery disease (TxCAD) was 85% by intracoronary ultrasound and 15% by angiography. By multiple regression analysis, only average fasting plasma triglyceride level (P < 0.006) and average weight (P < 0.007) were significantly correlated with severity of intimal thickening (R = 0.54, P < 0.0001). Donor age (P < 0.006) and average fasting plasma triglyceride level (P < 0.009) were significantly correlated with stenosis by angiography. Correlation of multiple immunologic and metabolic factors with intimal thickness by univariate analysis suggests a multifactorial etiology for TxCAD. Among the multiple univariate correlates of TxCAD, higher fasting plasma triglyceride levels and body weight are the only independent correlates of TxCAD. The absence of acute rejection as an independent predictor of intimal thickening suggests that mechanisms beyond those mediating typical cellular rejection should be targeted for advancing our understanding of Tx-CAD.

Predictive model to assess risk for cardiac allograft vasculopathy: an intravascular ultrasound study

OBJECTIVES

This study was performed to assess the influence and interdependence of immunologic and nonimmunologic risk factors in the development of cardiac allograft vasculopathy. Another primary objective was to establish a clinically useful model for risk assessment of cardiac allograft vasculopathy that would facilitate identifying those heart transplant recipients likely to have severe intimal proliferation and thereby at greater risk for adverse clinical events.

BACKGROUND

To our knowledge, no comprehensive intravascular ultrasound study has assessed the relative influences of both nonimmunologic and immunologic factors in the development of cardiac allograft vasculopathy, currently the major limitation to long-term cardiac allograft survival.

METHODS

Using a computer-assisted model of stepwise logistic regression, immunologic and nonimmunologic risk factors were evaluated to help identify the development of severe intimal thickening in 101 subjects who underwent intravascular ultrasound. Prospective validation of the findings was performed in a separate consecutive cohort of 37 heart transplant recipients, and the accuracy of this model to predict a relative risk > 1 for the development of severe intimal hyperplasia was assessed.

RESULTS

Significant independent predictors of severe intimal hyperplasia in this model included a donor age > 35 years, a first-year mean biopsy score > 1 (a measure not only of severity of rejection, but also of frequency of insidious rejection) and hypertriglyceridemia at two incremental levels of risk (150 to 250 mg/dl [1.70 to 2.83 mmol/liter] and > 250 mg/dl [2.83 mmol/liter]). Based on the absence (0) or presence (1) of these factors, 12 individual categories of risk were ascertained with increasing relative risks and predicted probabilities for severe intimal hyperplasia. Prospective validation of this model revealed a sensitivity and specificity of 70% and 90%, respectively, and the positive and negative predictive values were 85% and 80%, respectively. Additionally, subjects with severe intimal thickening had a four-fold higher cardiac event rate than those without severe intimal proliferation on intravascular ultrasound.

CONCLUSIONS

This study establishes a clinically useful predictive model that can be applied to individual heart transplant recipients to assess their risk for developing significant cardiac allograft vasculopathy and, thus, aids in the identification of patients at risk for cardiac events in whom closer surveillance and risk factor modification may be warranted.

Approaches to the treatment of hyperlipidemia in the solid organ transplant recipient

OBJECTIVE

To review the literature investigating increased lipid concentrations in transplant recipients and the use of lipid-lowering agents in this population.

DATA SOURCES

Relevant articles were identified from a MEDLINE search using the terms transplantation, hyperlipidemia, immunosuppression, and therapy including diet, gemfibrozil, bile acid sequestrants, nicotinic acid, probucol, and hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors. Selected literature, including controlled studies, was used in this review.

STUDY SELECTION

Articles published since 1970 pertaining to hyperlipidemia in solid organ transplant recipients. Emphasis was placed on clinical trials that investigated approaches to the treatment of hyperlipidemia in transplant recipients.

DATA EXTRACTION

Original articles and reviews were obtained to select material pertinent to the objectives.

DATA SYNTHESIS

Descriptions of lipid concentrations in the transplant patient and treatment approaches used, including potential complications, were reviewed.

CONCLUSIONS

Hyperlipidemia is an important risk factor for coronary heart disease in the solid organ transplant patient. Treatment alternatives include diet modification and, in most cases, pharmacologic intervention that should be based on the type of hyperlipidemia. The HMG-CoA reductase inhibitors are effective agents in the treatment of hyperlipidemia in the transplant recipient and generally are used as single therapy in low dosages to minimize the risk of myositis or rhabdomyolysis.

Successful abdominal aortic aneurysm resection in long-term survivors of cardiac transplantation

With the improvement of survival rates following cardiac transplantation, the probability of recipients developing extracardiac disease is increased. Three cases are reported of abdominal aortic aneurysm successfully operated on in cardiac allograft recipients 1 to 4 years after transplantation. Indications for transplantation were valvular, idiopathic and ischaemic cardiomyopathy. Post-transplant hypertension and hyperlipidaemia may have played a role in the rapid growth of the aneurysms. Cardiac function and the incidence of graft atherosclerosis were assessed before surgery by coronary angiography. All three patients were discharged from hospital. Abdominal aortic aneurysm resection may be a safe procedure in cardiac transplant patients. In view of the rapid increase in the size of the aneurysms in transplanted patients, careful screening should be performed during follow-up.

Dobutamine stress echocardiography in orthotopic heart transplant recipients. VACOMED Research Group

OBJECTIVES

This study sought to determine whether dobutamine stress echocardiography could accurately identify coronary artery disease after heart transplantation.

BACKGROUND

After heart transplantation, coronary artery disease is related to either diffuse concentric intimal thickening or focal stenosis and may be underdiagnosed by coronary angiography.

METHODS

We enrolled 41 patients, a mean (+/- SD) of 40 +/- 20 months after heart transplantation, at the time of their routine control coronary angiogram. Three patients were excluded because of poor echogenicity on the angiogram and one because of ventricular premature beats. Standard echocardiographic views were acquired at baseline and at incremental dobutamine infusion levels (from 5 to a maximal dose of 40 micrograms/kg body weight per min at 3-min intervals). Regional wall motion score was calculated from a 16-segment model, and each segment was graded from 1 (normal) to 4 (dyskinesia). Coronary angiography was performed 24 h after dobutamine stress echocardiography, and angiograms were analyzed in blinded manner.

RESULTS

Twenty-three (62%) of 37 patients had normal coronary angiographic findings. Dobutamine stress echocardiography showed abnormalities in only 2 of 23 patients. Fourteen patients (38%) had abnormal angiographic findings, seven of whom had stenoses > 50%. Dobutamine stress echocardiography correctly identified the corresponding hypoperfused segments in these seven patients. More of interest were the other seven patients, of whom three had angiographic nonsignificant stenoses (< 50%), and four had minor diffuse coronary irregularities. Dobutamine stress echocardiography showed hypokinesia in five of these seven patients despite nonsignificant lesions at coronary angiography. The respective overall sensitivity and specificity of dobutamine stress echocardiography were 86% and 91%. At follow-up, 2 of the 37 patients had an acute myocardial infarction. Both had abnormal findings on dobutamine stress echocardiography: One had normal coronary angiographic results, and one had significant coronary lesions.

CONCLUSIONS

Dobutamine stress echocardiography is a useful technique for the diagnosis of coronary artery disease after heart transplantation. These preliminary results indicate that dobutamine stress echocardiography may have a predictive value for further ischemic events in heart transplant recipients.

Efficacy and pharmacokinetics of simvastatin in heart transplant recipients

OBJECTIVE

To evaluate the efficacy and safety of simvastatin administered to a group of heart transplant patients receiving triple-drug immunosuppressive therapy. We also assessed the potential pharmacokinetic interaction between simvastatin and cyclosporine by comparing mean plasma concentrations of simvastatin beta-hydroxy acid, the major metabolite of the drug, in a group of heart transplant patients treated with cyclosporine and in a control group of patients who had not received heart transplants. Both groups received long-term (> 6 wk) simvastatin therapy.

DESIGN

We monitored hyperlipidemia in 20 hypercholesterolemic heart transplant patients receiving simvastatin 10 mg/d and triple-drug immunosuppressive therapy. Changes in laboratory results before and after 4 months of simvastatin therapy were considered. The same laboratory data were monitored in a control group of 20 nonhypercholesterolemic heart transplant patients who were not treated with simvastatin but were receiving triple-drug immunosuppressive therapy. Plasma concentrations of simvastatin beta-hydroxy acid were measured in 14 hypercholesterolemic patients, 7 of whom had received heart transplants and 7 who had not.

SETTING

The Division of Cardiology and the First Medical Clinic for the clinical study, as well as the Department of Pharmacology for the pharmacokinetic analysis.

PARTICIPANTS

Forty heart transplant patients and 7 hypercholesterolemic nontransplant patients.

MAIN OUTCOME MEASURES

Effectiveness of simvastatin was determined by comparing cholesterol and lipoprotein plasma concentrations in 20 patients who underwent heart transplant and were treated with simvastatin for 4 months. The safety of the drug was determined by analyzing changes in laboratory results in the treated group and in the control group, both those who had received heart transplants and those who had received immunosuppressive therapy.

RESULTS

After 4 months of simvastatin therapy, total cholesterol decreased by 12.5% and low-density lipoprotein cholesterol decreased by 21.3%. The only statistically significant laboratory change was an increase of 28.7% in the alanine aminotransferase concentrations. Plasma concentrations of simvastatin beta-hydroxy acid were higher in heart transplant patients than in those who had not received heart transplants, the control group.

CONCLUSIONS

Low-dosage simvastatin treatment seems to be safe and sufficiently effective to decrease cholesterol concentrations. Concomitant treatment with immunosuppressive therapy (primarily cyclosporine) in heart transplant patients appeared to cause a reduced metabolic clearance of simvastatin from the plasma. More extensive studies on the interaction between simvastatin and cyclosporine are needed to understand the marked variability found in the response to simvastatin.

Transient, severe hyperlipidemia in patients with acute lymphoblastic leukemia treated with prednisone and asparaginase

BACKGROUND

Corticosteroids and asparaginase inhibit protein synthesis. Many of their side effects are familiar to oncologists. Conversely, the possibility of therapy-induced hyperlipidemia generally is not appreciated. The incidence of severe hyperlipidemia during therapy of patients with acute lymphoblastic leukemia (ALL) who received prednisone and asparaginase was evaluated.

METHODS

During therapy with prednisone and asparaginase, a 10-year-old girl with precursor B ALL was identified with a peak plasma triglyceride and cholesterol level of 20,600 mg/dl and 1640 mg/dl, respectively. The lipid profile of the 60 patients in the protocol with this patient, the lipid profile of 64 patients on the previous high-risk ALL therapy program, and the literature were reviewed.

RESULTS

Five of 60 patients on the New York-II protocol experienced transient, marked (triglyceride level > or = 1000 mg/dl), benign hyperlipidemia. No such problem was observed in the 64 patients on the New York-I protocol. Five similar cases were found in the literature during therapy with steroids (2), asparaginase (2), or both (1). There were no characteristics that distinguished these 10 patients from the vast majority of patients on similar therapy without severe hyperlipidemia. Prolonged therapy with either agent seemed to increase the possibility of hyperlipidemia.

CONCLUSION

Severe hyperlipidemia during induction therapy for ALL is random, transient, and benign. Given the serious nature of the underlying disorder and the value of asparaginase and prednisone in its treatment, antileukemic therapy should not be modified when severe hyperlipidemia is observed.

Cardiac allograft vasculopathy assessed by intravascular ultrasonography and nonimmunologic risk factors

The genesis of cardiac allograft vasculopathy has been linked to nonimmunologic endothelial injury. Studies evaluating the role of nonimmunologic risk factors have thus far been limited to angiographic assessment. Intravascular ultrasound can detect cardiac allograft vasculopathy before it becomes angiographically evident. To assess the influence of nonimmunologic risk factors in the development of cardiac allograft vasculopathy, we studied 101 consecutive cardiac transplant recipients who underwent intracoronary ultrasound imaging during routine, annual coronary angiography. Based on the severity of intimal thickening, patients were divided into 2 groups: group 1 = minimal, mild, or moderate intimal thickness; and group 2 = severe intimal thickness. Cardiac transplant recipients with severe intimal thickness had higher levels of total cholesterol (267 +/- 70 vs 227 +/- 41 mg/dl, p = 0.0008), low-density lipoprotein cholesterol (187 +/- 47 vs 139 +/- 31 mg/dl, p = 0.0001), and triglycerides (237 +/- 75 vs 182 +/- 88 mg/dl, p = 0.0004), a higher percentage of weight gain (12 +/- 4% vs 8 +/- 5%, p = 0.0001), a larger body mass index (30 +/- 4 vs 25 +/- 3, p = 0.0001), and older donor age (27 +/- 5 vs 23 +/- 7 years, p = 0.005) than recipients with mild or moderate intimal thickness. Multiple regression analysis established that total cholesterol, low-density lipoprotein cholesterol, triglyceride levels, obesity indexes, donor age, and years following cardiac transplantation (p < 0.01) were independent predictors of the severity of intimal thickening, and thus the severity of cardiac allograft vasculopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the effectiveness of lovastatin therapy for hypercholesterolemia after heart transplantation between patients with and without pretransplant atherosclerotic coronary artery disease

With the aim of assessing the effectiveness and safety of lovastatin in patients with hypercholesterolemia after heart transplantation, as well as the potential differences in the lipid-lowering effect of lovastatin between patients with or without pretransplant coronary artery disease (CAD), we studied 63 heart transplant patients who had serum total cholesterol > 250 mg/dl in spite of dietary therapy. Mean age of subjects was 47 +/- 2 years. Triple-drug immunosuppressive therapy consisted of cyclosporine, azathioprine, and steroids. Thirty-nine patients (62%) had pretransplant CAD and 24 (38%) did not. Pretreatment serum lipid levels were: total cholesterol, 302 +/- 32 mg/dl; low-density lipoprotein (LDL) cholesterol, 201 +/- 35 mg/dl; high-density lipoprotein (HDL) cholesterol, 60 +/- 19 mg/dl; triglycerides, 205 +/- 86 mg/dl; and total/HDL cholesterol ratio, 5.4 +/- 1.6. Patients received 10 to 40 mg/day of lovastatin (mean dose 17 +/- 6) for 13 +/- 4 months. There were no serious adverse events. At 3 months, lovastatin decreased total cholesterol by 15% (p < 0.001), LDL cholesterol by 21% (p < 0.001), triglycerides by 17% (p < 0.05), and total/HDL cholesterol ratio by 17% (p < 0.001), and increased HDL cholesterol by 3% (NS). Although lovastatin was effective in both patients with pretransplant CAD and non-CAD, analysis of its effect in each subgroup (CAD and non-CAD) revealed that its lipid-lowering effect was higher for non-CAD patients (-20% vs -12% for total cholesterol, and -27% vs -17% for LDL cholesterol, both p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Metabolic risk factors for atherosclerosis in heart transplant recipients

Development of coronary artery disease (CAD) in the cardiac allograft limits long-term survival after heart transplantation. Previous studies, focusing on lipoprotein metabolism, have paid little attention to changes in glucose and insulin metabolism that increase the risk of CAD in these patients. To address this issue, plasma glucose and insulin responses to an oral glucose load and lipid and lipoprotein concentrations were measured in male normal volunteers (n = 40) and cardiac transplant recipients with pretransplant diagnoses of either idiopathic cardiomyopathy (n = 24) or ischemic heart disease (n = 28), matched for age and body mass index. Patients with a pretransplant diagnosis of ischemic heart disease had higher plasma glucose and insulin concentrations in response to oral glucose as well as higher fasting plasma triglyceride, cholesterol, and low-density lipoprotein cholesterol concentrations than did the control group (p < 0.005 to p < 0.001). In addition, high-density lipoprotein cholesterol concentrations were lower and the ratio of cholesterol to high-density lipoprotein cholesterol higher than control values in those with a pretransplant diagnosis of ischemic heart disease (p < 0.001). Values for almost all variables were intermediate in patients with a pretransplant diagnosis of idiopathic cardiomyopathy and in most instances were significantly different from both. Thus, male cardiac transplant recipients are dyslipidemic, relatively glucose intolerant, and hyperinsulinemic compared to normal volunteers. These changes, observed in patients with a pretransplant diagnosis of either ischemic heart disease or idiopathic cardiomyopathy, emphasize the important role of immunosuppression in the development of metabolic risk factors for CAD in these individuals.

Cholesterol-lowering intervention and coronary artery disease after cardiac transplantation

Allograft coronary artery disease is a major threat to long-term survival after cardiac transplantation. It has been suggested that hyperlipidemia plays a major role in allograft coronary disease. The objective of the present study was to evaluate the effect of a lipid-lowering intervention with diet and drug therapy after cardiac transplantation. Forty-six patients who underwent transplantation between 1988 and 1991 and who were treated with the American Heart Association phase 1 diet and an HMG coenzyme A reductase inhibitor (lovastatin or simvastatin) when low-density lipoprotein cholesterol levels were higher than 3.4 mmol/L were compared with 35 untreated patients having transplantation between 1983 and 1988. Annual coronary angiograms were obtained in both groups. Cholesterol, triglyceride, and low-density lipoprotein levels were significantly lower in the treated group. Actuarial survival and event-free survival (survival free from allograft coronary artery disease) were similar in both groups. Low-density lipoprotein levels lower than 3 mmol/L at the last follow-up had a positive effect on event-free survival. The cholesterol-lowering intervention was not effective in decreasing the prevalence of allograft coronary artery disease. This study suggests that more aggressive measures to lower low-density lipoprotein levels may be necessary to significantly affect allograft disease. Clinical trials should be developed to address this hypothesis.

Secondary causes of hyperlipidemia

Secondary causes of hyperlipidemia are important to recognize. In fact, hyperlipidemia may be a clue to the presence of an underlying systemic disorder. It may greatly heighten the risk of atherosclerosis with a raised LDL-c, triglyceride-rich lipoprotein excess, and increased lipoprotein(a) as well as lowered HDL-c. The search for secondary causes may provide a clue as to why patients with primary lipid disorders suddenly develop worsening lipid profiles. The point is a crucial one because some acquired causes of hyperlipidemia, such as alcohol, estrogens, steroids, or pregnancy, when superimposed on a primary familial form of hypertriglyceridemia can result in a saturated removal system and a buildup of chylomicrons, which can lead to life-threatening pancreatitis. A convenient way to remember secondary causes is to think of the four D's of diet, drugs, disorders of metabolism, and diseases. Although diets rich in saturated fats and cholesterol are a common cause of the mild hypercholesterolemia seen in our society, alcohol excess and weight gain can explain much of the tendency toward hypertriglyceridemia. Interestingly anorexia nervosa has long been associated with severe but reversible hypercholesterolemia. Several classes of drugs need to be considered as common causes of altered lipid profiles. Glucocorticoids and estrogens elevate triglycerides and raise levels of HDL-c. Anabolic steroids taken orally markedly reduce levels of HDL-c in contrast to injectable testosterone, which does not adversely affect the LDL-to-HDL ratio. Oral contraceptives affect atherosclerotic risk depending on the kind and doses of progestin/estrogen. In those with an underlying primary hypertriglyceridemia and associated obesity, estrogenic medications can depress triglyceride removal mechanisms, leading to the chylomicronemia syndrome and pancreatitis. Antihypertensives have variable effects on lipids and lipoproteins. Although short-term thiazide usage raises cholesterol, triglycerides, and LDL-c, long-term usage is not necessarily associated with significant alterations in lipid levels. Alpha blockers may cause an increase in HDL-c, whereas beta blockers raise triglycerides and lower HDL-c. Sympatholytics, angiotensin converting enzyme inhibitors, and calcium channel blockers are essentially lipid neutral. Retinoids can be associated with increased LDL-to-HDL ratios and occasionally striking elevations in triglycerides. Cyclosporine raises LDL-c and lipoprotein(a). Classes of drugs that may raise HDL-c include cimetidine, antiepileptic drugs, and tamoxifen, but the effect may be seen primarily in women. Hypothyroidism is the most common secondary cause of hyperlipidemia after dietary causes are considered. A thyroxine and TSH level should be obtained on all new cases of clinically important hyperlipidemia.(ABSTRACT TRUNCATED AT 400 WORDS)

Low-density lipoprotein metabolism in rats treated with cyclosporine

Metabolic mechanisms underlying the observations of elevated cholesterol concentration of low-density lipoprotein (LDL) in organ-transplanted patients on long-term immunosuppressant cyclosporine therapy were explored using cyclosporine-treated rats as an experimental model. As in patients, treatment with cyclosporine induced a significant elevation of plasma cholesterol level, mainly in LDL cholesterol, with a decrease in high-density lipoprotein (HDL) cholesterol level. In an in vivo cross-over study design, differentially radioiodinated homologous LDL from donor cyclosporine-treated rats (Cyc-LDL) and excipient-only-treated control rats (Exc-LDL) were injected into recipient cyclosporine-treated rats (Cyc-rats), excipient-only--treated control rats (Exc-rats), and untreated rats (Unt-rats). From the isotope disappearance curves, the fractional catabolic rate (FCR) and production rate were calculated. The results showed that FCR and production rate were significantly reduced in Cyc-rats compared with control Exc-rats and Unt-rats. The decrease was independent of the donor LDL source. In vitro LDL ligand-receptor assays indicated a twofold higher degradation of Cyc-LDL by cultured rat fibroblasts, and hence could not account for the decreased clearance observed in vivo. These results suggest that the elevated concentrations of LDL cholesterol associated with cyclosporine treatment result not from a cyclosporine-induced modification of the LDL molecule, which could diminish its receptor-mediated clearance/catabolism, but possibly from an in vivo pharmacological property of cyclosporine such as an induced hepatic dysfunction.

Short-term effect of various doses of cyclosporin A on plasma lipoproteins and its distribution in blood: an experimental study

Hyperlipidaemia commonly develops in both transplant recipients and experimental animals receiving cyclosporin A (CsA). However, the threshold of CsA induced-changes on lipoproteins and the role of parenteral vehicle (cremophor) has not been defined. Male Wistar rats were classified into five groups of six animals each and received CsA in cremophor vehicle at doses of 5, 10 or 20 mg kg-1 d-1, s.c., vehicle alone or saline for 7 d. Blood was obtained 24 h after the last dose and plasma was analysed. Plasma very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein subfractions (HDL-2, HDL-3) were isolated by sequential ultracentrifugation and their content of cholesterol, triglyceride and phospholipid was determined. Whole blood and trough plasma CsA levels were measured by monoclonal radioimmunoassay. Plasma lipids did not differ significantly among the five groups. At a dose of 20 mg kg-1 d-1 of CsA VLDL cholesterol rose significantly (P < 0.05). Administration of either CsA or cremophor vehicle increased HDL-2 phospholipids (P < 0.05) and decreased HDL-3 cholesterol. There was not a linear relationship between whole blood and plasma CsA levels and increasing CsA doses. Short-term treatment with low doses of CsA have little influence on lipid profile in the rat. Changes on lipoprotein composition can be attributed mainly to cremophor vehicle, conceivably due to its ethanol content.

Maxepa versus bezafibrate in hyperlipidemic cardiac transplant recipients

Accelerated coronary artery disease is the most serious obstacle to long-term survival in cardiac transplant recipients. Lipid abnormalities are found frequently in these patients, and there is growing evidence that even minimally increased levels of cholesterol and triglycerides contribute to the development of accelerated coronary artery disease. However, the optimal lipid-lowering therapy after cardiac transplantation has not been defined. In an open, randomized study, the efficacy and safety of bezafibrate (400 mg/day) and fish oil (Maxepa) (10 g/day) for 3 months were compared in 87 cardiac transplant recipients with serum total cholesterol > 6.5 or triglycerides > 2.8 mmol/liter, or both. After 1 month, bezafibrate reduced total cholesterol by 13%, low-density lipoprotein cholesterol by 20% and apolipoprotein B by 13%. It also increased apolipoprotein A1 and high-density lipoprotein cholesterol by 12 and 20%, respectively, and significantly reduced fibrinogen at 3 months. Maxepa had no significant effect on these variables, but was as effective as bezafibrate in reducing triglycerides (36 and 31%, respectively). Both drugs increased lipoprotein (a) to a similar extent, and bezafibrate significantly increased serum creatinine. These results suggest that bezafibrate has better lipid-, apolipoprotein- and hemostatic modifying properties than does Maxepa, but its potentially adverse effect on renal function needs further investigation.