Carvedilol treatment of kidney graft recipients with chronic rejection

Superior rejection profile during the first 24 months after heart transplantation under tacrolimus as baseline immunosuppressive regimen

Background

The use of tacrolimus (TAC) in patients after heart transplantation (HTX) has increased over the last few years.

Aim

In this retrospective study, we evaluated the effects of a TAC (conventional and extended-release TAC)-based immunosuppressive therapy regarding rejection profile in comparison to a cyclosporine A (CSA)-based regimen in patients after HTX.

Methods

The data of 233 patients who underwent HTX at the Heidelberg Heart Transplantation Center from May 1998 until November 2010 were retrospectively analyzed. Primary immunosuppressive therapy was changed from a CSA (n=114) to a TAC (n=119)-based regimen in February 2006 according to center routine. Follow-up period was 2 years post-HTX. Primary endpoint was time to first biopsy-proven rejection requiring therapy. In all patients, routine follow-up at the Heidelberg Heart Transplantation Center was mandatory.

Results

Multivariate risk factor analysis regarding time to first rejection episode showed no statistically significant differences regarding recipient age, donor age, recipient sex, donor sex, sex mismatch, ischemic time, and diagnosis leading to HTX between the two groups (all P= not statistically significant). Time to first biopsy-proven rejection was significantly longer in the TAC group (intention-to-treat analysis, n=233, log-rank test P<0.0001; per-protocol analysis, n=150, log-rank test P=0.0003). In patients who underwent a change of primary immunosuppression (n=49), a significantly longer time to first biopsy-proven rejection was also found in the primary TAC subgroup (log-rank test P=0.0297). Further subgroup analysis in the TAC subgroups showed no statistically significant differences in time to biopsy-proven rejection under extended-release TAC compared to conventional TAC (intention-to-treat analysis, log-rank test P=0.1736).

Conclusion

Our study demonstrated that a TAC-based primary immunosuppressive therapy is superior to a CSA-based immunosuppressive regimen in patients after HTX regarding time to first biopsy-proven rejection.

Comparison of carvedilol and metoprolol on serum lipid concentration in diabetic hypertensive patients

CONTEXT

Vasoconstricting beta-blocker use is associated with a reduction in HDL cholesterol, higher triglyceride, total cholesterol and LDL cholesterol levels, whereas carvedilol, a vasodilating beta-blocker, has not been associated with these effects.

OBJECTIVE

To compare in a randomized, double-blind study, the effects of the beta 1-blocker metoprolol tartrate with the combined alpha 1, beta-blocker carvedilol on serum lipid concentrations.

METHODS

A prospective randomized, double-blind, parallel-group trial compared the effects of carvedilol and metoprolol on total cholesterol, triglycerides, calculated LDL, HDL and non-HDL cholesterol levels at baseline and after 5 months of therapy as a secondary objective in the Glycemic Effects in Diabetes Mellitus: Carvedilol-Metoprolol Comparison in Hypertensive (GEMINI) study. In this study, 1235 participants with type 2 diabetes and hypertension who were receiving renin-angiotensin system blockers were randomized either to carvedilol, receiving 6.25-25 mg twice daily, or to metoprolol tartrate, receiving 50-200 mg twice daily. If needed, hydrochlorothiazide and a dihydropyridine calcium channel blocker were added to achieve blood pressure goals.

RESULTS

In the metoprolol tartrate group, triglycerides and non-HDL cholesterol increased and both the LDL and the HDL cholesterol levels decreased. In the carvedilol group, total LDL and HDL cholesterol decreased, non-HDL cholesterol was unchanged and triglycerides increased. Comparing the carvedilol and metoprolol tartrate groups, there was no statistically significant difference in LDL and HDL cholesterol levels, but there was a significantly greater decreases with carvedilol in total cholesterol [-2.9%, 95% confidence interval (CI) -4.60 to -1.15, p < 0.001], triglycerides (-9.8%, 95% CI -13.7, -5.75%, p < 0.001) and non-HDL cholesterol (-4.03%, 95% CI -6.3 to -1.8, p < 0.0006). At the end of the study, significantly more participants in the metoprolol tartrate group had had initiation of statin therapy or the statin dose increased than those in the carvedilol group (11 vs. 32%, p = 0.04).

CONCLUSIONS

In patients with type 2 diabetes currently receiving a renin-angiotensin blocker, compared with metoprolol tartrate, the addition of carvedilol for blood pressure control resulted in a significant decrease in triglyceride, total cholesterol and non-HDL cholesterol levels. The use of metoprolol resulted in a significantly greater rate of initiation of statin therapy or an increase in the dose of existing statin therapy when compared with carvedilol utilization.

Impact of carvedilol on the serum lipid profile

OBJECTIVE

To examine the evidence regarding the impact of carvedilol on the serum lipid profile.

DATA SOURCES

Searches in MEDLINE and International Pharmaceutical Abstracts (1966-December 2007) were conducted. Search terms included carvedilol, cholesterol, lipids, hyperlipidemia, and beta-blockers.

STUDY SELECTION AND DATA EXTRACTION

Published studies and case reports that evaluated the impact of carvedilol on the lipid profile were reviewed. One study was excluded because it evaluated carvedilol for an off-label use and was a small Phase 2 pilot study that evaluated the results of only 10 patients.

DATA SYNTHESIS

Twelve studies were available for review; 6 of these compared carvedilol with beta(1)-selective antagonists. Three studies compared carvedilol with other antihypertensive medications; 2 of those studies evaluated total cholesterol only. Carvedilol alone was evaluated for its effects on lipids in 3 small single-group studies. In 4 of the 12 studies, carvedilol independently improved the lipid profile significantly, while the drug had a nonsignificant, neutral effect on the lipid profile in 3 studies. Furthermore, in 4 of the 12 studies, carvedilol was compared with other antihypertensive medications. In 3 of these 4 studies, the other drugs worsened the lipid profile significantly compared with carvedilol, while carvedilol significantly improved the lipid profile in the other study. Finally, carvedilol had a potentially negative effect on high-density lipoprotein cholesterol in a single-group study, but p values were not reported.

CONCLUSIONS

It is clear that beta(1)-selective antagonists worsen the lipid profile compared with carvedilol. However, it is unclear whether carvedilol independently makes an improvement or has a neutral effect on the lipid profile. Carvedilol should be an important treatment consideration in patients with heart failure and/or hypertension with dyslipidemia. However, many questions remain regarding this issue.

Renal allograft protection with angiotensin II type 1 receptor antagonists

The renal benefits of agents inhibiting the renin-angiotensin-aldosterone system in renal transplant recipients, i.e. preventing the development of chronic graft nephropathy, are supposed but not finally proven. In a double-blind, placebo-controlled, cross-over study, we evaluated the influence of losartan on surrogate markers of tubular injury, urine excretion of transforming growth factor beta-1 (TGF-beta1) and amino-terminal propeptide of type III procollagen (PIIINP) in 16 patients after transplantation. The patients received randomly either losartan (50-100 mg daily) or the beta-blocker carvedilol (12.5-25 mg) for 8 weeks, allowing a placebo washout between treatments. The target office through blood pressure (BP) was below 130/85 mmHg. The BP did not differ in the treatment periods. Losartan significantly decreased N-acetyl-beta-d-glucosaminidase and alfa-1 microglobulin excretion relative to placebo and carvedilol. Urine excretion of TGF-beta1 and PIIINP was significantly lower after losartan. In conclusion, losartan reduces urine excretion of proteins associated with tubular damage and graft fibrosis.

Oxidative stress in chronic renal allograft nephropathy in rats: effects of long-term treatment with carvedilol, BM 91.0228, or alpha-tocopherol

Oxidative stress is markedly increased after kidney transplantation and may participate in the development and/or progression of chronic renal allograft nephropathy. In the present study we sought to assess the nephroprotective potential of antioxidative treatment in renal allograft recipients. Experiments were performed in the Fisher-Lewis rat model of chronic renal allograft nephropathy, with isografted Lewis rats serving as controls. Allografted rats were orally treated with carvedilol, an antihypertensive drug with antioxidative properties (25 mg/kg/d), its purely antioxidative derivative BM 91.0228 (5 mg/kg/d), alpha-tocopherol (100 mg/kg/d), a combination of propranolol/doxazosine (10/5 mg/kg/d), or vehicle for 24 weeks. At the end of the study, oxidative status and influence of antioxidative treatment were assessed in transplanted animals. Chronic allograft nephropathy was characterized by a marked increase of markers for oxidative stress (increased plasma and kidney levels of malondialdehyde, reduced glutathione, and tocopherol levels in renal allografts). Treatment with carvedilol, BM 91.0228, and tocopherol significantly improved antioxidative status of allograft kidney recipients. In addition, carvedilol reduced elevated blood pressure in allografted rats. However none of the drugs had a beneficial influence on functional and morphologic renal changes. Our data thus demonstrate that long-term treatment with the antioxidants carvedilol, BM 91.0228, or alpha-tocopherol does not prevent development of chronic transplant nephropathy, despite an improvement of antioxidative status.

Treatment of hypertension in renal transplant recipients

PURPOSE OF REVIEW

Hypertension is very common in renal transplant recipients and is a significant risk factor for mortality from cardiovascular diseases and for development of graft dysfunction.

RECENT FINDINGS

Recent guidelines for the treatment of hypertension (Joint National Committee on Prevention, Detection, and Treatment of High Blood Pressure VI Report and World Health Organization Guidelines) do not directly address post-transplant hypertension. Specific recommendations for the drug treatment of hypertension in renal allograft recipients have not been given in the Clinical Practice Guidelines of the American Society of Transplantation or those of the European Renal Association.

SUMMARY

The present paper summarizes some important aspects of post-transplant hypertension and discusses potential treatment strategies aimed at reducing blood pressure and thus improving patient and allograft survival.

Carvedilol: molecular and cellular basis for its multifaceted therapeutic potential

Carvedilol is a unique cardiovascular drug of multifaceted therapeutic potential. Its major molecular targets recognized to date are membrane adrenoceptors (beta 1, beta 2, and alpha 1), reactive oxygen species, and ion channels (K+ and Ca2+). Carvedilol provides prominent hemodynamic benefits mainly through a balanced adrenoceptor blockade, which causes a reduction in cardiac work in association with peripheral vasodilation. This drug assures remarkable cardiovascular protection through its antiproliferative/atherogenic, antiischemic, antihypertrophic, and antiarrhythmic actions. These actions are a consequence of its potent antioxidant effects, amelioration of glucose/lipid metabolism, modulation of neurohumoral factors, and modulation of cardiac electrophysiologic properties. The usefulness of carvedilol in the treatment of hypertension, ischemic heart disease, and congestive heart failure is based on a combination of hemodynamic benefits and cardiovascular protection.