Prospective study of lipid disorders in FK506-versus cyclosporine-treated renal transplant patients

Management of dyslipidemia in adult solid organ transplant recipients

Solid organ transplantation (SOT) has revolutionized treatment of end-stage disease. Improvements in the SOT continuum of care have unmasked a significant burden of cardiovascular disease, manifesting as a leading cause of morbidity and mortality. Although several risk factors for development of post-transplant cardiovascular disease exist, dyslipidemia remains one of the most frequent and modifiable risks. An important contributor to dyslipidemia in SOT recipients is the off-target metabolic effects of immunosuppressive medications, which may alter lipoproteins and their metabolism. Dyslipidemia management is paramount as lipid-lowering therapy with statins has demonstrated reductions in graft vasculopathy, decreased rejection rates, and improved survival. Several nonstatin medication options are available, but data supporting their benefit in the SOT population are minimal, typically extrapolated from studies in the general population. Further compounding dyslipidemia management is the complex interplay of drug interactions between lipid-lowering and immunosuppressant medications, which can result in serious toxicity and/or therapeutic failure.

Mechanism of tacrolimus-induced chronic renal fibrosis following transplantation is regulated by ox-LDL and its receptor, LOX-1

Chronic renal allograft dysfunction (CRAD) is the most common cause of graft failure following renal transplantation. However, the underlying mechanisms remain to be fully elucidated. Immunosuppressants and hyperlipidemia are associated with renal fibrosis following long-term use. The present study aimed to determine the effects of tacrolimus (FK506) and lipid metabolism disorder on CRAD. In vitro and in vivo models were used for this investigation. Cells of the mouse proximal renal tubular epithelial cell strain, NRK-52E, were cultured either with oxidized low-density lipoprotein (ox-LDL), FK506, ox-LDL combined with FK506, or vehicle, respectively. Changes in cell morphology and changes in the levels of lectin-like ox-LDL receptor-1 (LOX-1), reactive oxygen species (ROS), hydrogen peroxide and fibrosis-associated genes were evaluated at 24, 48 and 72 h. In separate experiment, total of 60 Sprague-Dawley rats were divided randomly into four groups, which included a high-fat group, FK506 group, high-fat combined with FK506 group, and control group. After 2, 4 and 8 weeks, the serum lipid levels, the levels of ox-LDL, ROS, and the expression levels of transforming growth factor (TGF)-β1 and connective tissue growth factor were determined. The in vitro and in vivo models revealed that lipid metabolism disorder and FK506 caused oxidative stress and a fibrogenic response. In addition, decreased levels of LOX-1 markedly reduced the levels of TGF-β1 in the in vitro model. Taken together, FK506 and dyslipidemia were found to be associated with CRAD following transplantation.

Different Effects of Tacrolimus on Innate and Adaptive Immune Cells in the Allograft Transplantation

While tacrolimus (FK506) is currently used as immunosuppression therapy in transplant recipient, the immunological mechanism remains unknown. Herein, the immunoregulatory effects of FK506 were investigated in the physiological status and allogeneic skin transplantation. FK506 cannot significantly alter the functions of innate immune cells (macrophages and neutrophils) and adaptive immune cells (T cells) in the physiological status. However, it can effectively delay allogeneic skin-graft rejection through ameliorating the T cell responses, but not myeloid-derived innate immune cell responses. Importantly, it did not affect the allograft recipient macrophage innate immune defence capacity to bacteria. In clinics, FK506 treatment can significantly control the cytokine production in T cells, but not non-T cells. This study shows targeting calcineurin signalling, FK506, to be essential in inducing allograft tolerance, but not to damage the innate defence capacity, validating the immune cell phenotypes as a potential marker in transplantation following FK506 treatment.

New onset dyslipidemia after renal transplantation: is there a difference between tacrolimus and cyclosporine?

Lipid abnormalities including increased total cholesterol (TC), triglycerides (TG) and low density lipoprotein cholesterol (LDL-C) have been frequently reported in renal transplantation and could be involved in the high frequency of cardiovascular diseases in this population.

PATIENTS AND METHODS

Two hundred ninety-five patients were transplanted between January 1995 and October 2000 in our center. Two hundred two patients were included in this study. Seventy-six patients received tacrolimus (Tac), and 126 patients cyclosporine (CsA). Lipid parameters were assessed the day of transplantation and 1 year posttransplantation.

RESULTS

Serum lipids were similar between the two groups at D0. At M12, TC and LDL-C were significantly higher in the CsA group (6.14 +/- 1.37 vs 5.28 +/- 1.32 mmol/L; P < .05 and 3.98 +/- 1.05 vs 3.26 +/- 1.03 mmol/L; P < .05 CsA vs Tac, respectively). TG were comparable in both groups (1.86 +/- 1.07 vs 1.62 +/- 0.92 mmol/L; P = .55; CsA vs Tac). Incidence of de novo hypercholesterolemia was significantly higher in the CsA group (28 vs 8%) whereas incidence of hyperTG was similar in both groups. Prevalence of LDL-C was significantly higher in the CsA group (65% vs 31%; P < .001), whereas there was no difference in high density lipoprotein (HDL)-C levels.

DISCUSSION

Mean serum lipid levels and incidence and prevalence of hyperTC, especially LDL-C, was significantly higher in patients receiving CsA when compared with Tac. TG and HDL-C levels were similar. Although the study was retrospective, our results confirm that CsA increases lipid levels, whereas Tac does not.

CONCLUSION

Lipid disorders are frequently observed in renal transplant recipients. CsA, but not Tac, significantly increases incidence and prevalence of high TC and LDL-C.

Preventing cardiovascular outcome in patients with renal impairment: is there a role for lipid-lowering therapy?

Patients with chronic kidney disease (CKD), ranging from modest renal impairment to dialysis and transplant, have an increased risk for cardiovascular disease (CVD). Patients with CKD have both traditional and non-traditional risk factors for CVD. The role of lipids as risk factors for CVD in these populations has not been firmly established. In a recent prospective controlled trial, it was established that atherogenic lipids are indeed strong risk factors for CVD in renal transplant recipients, and that treatment with a HMG-CoA reductase inhibitor reduced the incidence of cardiac death and myocardial infarction. For patients receiving dialysis, the association between serum lipid levels and cardiovascular outcome is uncertain and there is no evidence from controlled trials that lipid-lowering therapy does have a beneficial effect on cardiovascular outcome in these patients. Atherogenic lipids are probably a risk factor for patients with mild or moderate CKD, and five subgroup analyses have indicated a favorable effect of lipid-lowering therapy on cardiovascular outcome, although we still lack prospective controlled trials in these patients. CVD in patients with CKD has been a neglected area of research.

Kidney transplantation: determination of the problems encountered by Turkish patients and their knowledge and practices on healthy living

BACKGROUND

Although renal transplantations remove many limitations, dialysis can improve quality life in patients with end-stage renal disease, once transplantation has been performed and the patient has been discharged with a functioning graft, life with a chronic illness continues.

AIMS AND OBJECTIVES

This study was carried out to define problems encountered by patients undergoing kidney transplantation and their knowledge and practices on healthy living.

DESIGN

This study was designed as a retrospective and descriptive survey.

METHODS

This study was performed on 125 patients who were followed at Social Insurance Institute's Ankara Specialty Hospital Transplantation Clinic between March and August 2001. A convenience sample was drawn from the population of renal transplant patients. A questionnaire was prepared based on the literature, which included patients' socio-demographic information, physiological problems, diseases and repeated hospitalizations; side-effects and usage of immunosuppressive drugs, knowledge and practices of patients regarding healthy living and their knowledge needs. Data were collected through interviews. Percentage and chi-square test were used in evaluation of the data.

RESULTS

Physiological problems and diseases after renal transplantations were seen such as 38.4% had infections in urinary and respiratory tract. Some had hypertension (22.4%) hypercholesterolaemia (26.5%) and 5.6% had malignancy. Most (67.2%) developed antirejection drugs side-effects. About 55.2% were admitted to hospital after renal transplantation and 68.8% had not received any training after transplantation from a health professional. Only 35.2% knew the signs and symptoms of rejection entirely or partly. It was determined that 55.2% stated that they avoid sunlight and 56% stated that they exercise regularly. Only 26.8% of female patients do regular breast self-examination. While 52.8% listed the forbidden foods correctly, only 27.2% could list the forbidden beverages accurately.

CONCLUSIONS

According to the results, patients undergoing renal transplantation experience various problems that may influence their quality of life adversely and their knowledge and practice is not adequate for them to continue to lead healthy lives.

RELEVANCE TO CLINICAL PRACTICE

In accordance with the results of the study, offering continuing education and counselling services, preparing training guides, brochures, video cassettes and CDs for patient education, improving the national web sites to inform the public and creation of a home care system were suggested.

Calcineurin inhibitors and post-transplant hyperlipidaemias

Cardiovascular disease is now the leading cause of death in transplant recipients. This is due, in part, to the vulnerability of these patients to a complicated set of conditions including hypertension, diabetes mellitus, and post-transplant hyperlipidaemia (PTHL). PTHL is characterised by persistent elevations in total serum cholesterol, low density lipoprotein cholesterol and triglyceride levels. The causes of PTHL are complex and not fully understood, however several classes of immunosuppressants including the corticosteroids, rapamycins and calcineurin inhibitors, appear to play a role. PTHL has been observed in most studies in which patients received calcineurin inhibitor-based regimens, and has been observed with both tacrolimus and cyclosporin. Comparing these calcineurin inhibitors with regard to the relative incidence or severity of PTHL occurring during treatment is difficult because of the use of higher doses of corticosteroids in cyclosporin-based regimens, as compared with tacrolimus-based regimens. However, current expert opinion suggests that the discrepancies in the relative incidence and severity of PTHL are largely accounted for by this difference in corticosteroid dose. At this point in time, evidence for potential differences is scant and inconclusive. Further study is needed, not only to investigate differences in lipid profile, but also of the relative effects of these immunosuppressants on long term graft function as well as on cardiovascular morbidity and mortality. PTHL can be successfully managed with a combination of dietary management, reduction and, if appropriate, withdrawal of corticosteroids, and the administration of lipid-lowering drugs. With this combination of therapeutic options, the threats to long term health posed by PTHL may be effectively addressed.

Syndrome X following renal transplantation

The cardiovascular risk factors that accompany postrenal transplantation include an atherogenic lipid profile, hypertension, new-onset diabetes mellitus, and a chronic prothrombotic state. This picture describes the dysmetabolic syndrome or syndrome X, which can significantly aggravate not only the risk of cardiovascular disease and death in this population, but also the progression of allograft dysfunction. The recognition and aggressive management of the dysmetabolic syndrome in postrenal allograft recipients may have a favorable impact on the incidence of cardiovascular morbidity and mortality in these patients and prolong allograft function.