Treatment with losartan in kidney transplant recipients with posttransplant erythrocytosis

Effect of angiotensin II type-1 receptor blockers on stable allograft kidneys: prospective randomized study

OBJECTIVE

Is assess the effects of angiotensin II type-I receptor blockers on outcomes in renal transplant recipients without proteinuria or posttransplantation erythrocytosis.

PATIENTS AND METHODS

Fifty renal transplant recipients (30 men and 20 women, with a mean [SD] age of 40 [13] years) were randomized into 2 groups of 25 patients each; 1 group was treated with losartan for 1 year, and the other was not (control group). Blood pressure and other biochemical parameters were measured at baseline and at 6 and 12 months posttransplantation.

RESULTS

After 1 year, the losartan group had significantly lower systolic blood pressure (113 [22] mm Hg vs 126 [18] mm Hg; P = .04) and hemoglobin concentration (12.8 [1.9] g/dL vs 14.5 [2.1] g/dL; P = .006) and significantly higher serum high-density lipoprotein cholesterol concentration (58 [22] mg/dL vs 47 [10] mg/dL; P = .03) compared with the control group; however the incidence of anemia did not differ (37% vs 20%; P = .20). In the losartan group, there were significant changes in hemoglobin concentration between baseline and 6 months (14.5 [1.6] g/dL vs 12.9 [1.49] g/dL; P < .001), but not between 6 and 12 months (12.9 [1.49] g/dL vs 12.8 [1.96] g/dL; P = .43). After 1 year, there were no significant between-group differences in diastolic hypertension, serum creatinine concentration, creatinine clearance, and serum potassium, low-density lipoprotein cholesterol, triglyceride, and uric acid concentrations.

CONCLUSION

Losartan significantly increased high-density lipoprotein concentration and significantly decreased systolic hypertension. Although losartan decreased the hemoglobin concentration during the first 6 months, its effect did not progress with longer use. To determine the effect of losartan on renal function, additional studies with longer follow-up are needed.

Antihypertensive treatment for kidney transplant recipients

BACKGROUND

In some nontransplant populations, effects of different antihypertensive drug classes vary. Relative effects in kidney transplant recipients are uncertain.

OBJECTIVES

To assess comparative effects of different classes of antihypertensive agents in kidney transplant recipients.

SEARCH STRATEGY

MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, conference proceedings and reference lists of identified studies were searched.

SELECTION CRITERIA

Randomised controlled trials of any antihypertensive agent applied to kidney transplant recipients for at least two weeks were included.

DATA COLLECTION AND ANALYSIS

Data was extracted by two investigators independently. Study quality, transplant outcomes and other patient centred outcomes were assessed using random effects meta-analysis. Risk ratios (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes, both with 95% confidence intervals (CI) were calculated. Stratified analyses and meta-regression were used to investigate heterogeneity.

MAIN RESULTS

We identified 60 studies, enrolling 3802 recipients. Twenty-nine studies (2262 participants) compared calcium channel blockers (CCB) to placebo/no treatment, 10 studies (445 participants) compared angiotensin converting enzyme inhibitors (ACEi) to placebo/no treatment and seven studies (405 participants) compared CCB to ACEi. CCB compared to placebo/no treatment (plus additional agents in either arm as required) reduced graft loss (RR 0.75, 95% CI 0.57 to 0.99) and improved glomerular filtration rate (GFR), (MD, 4.45 mL/min, 95% CI 2.22 to 6.68). Data on ACEi versus placebo/no treatment were inconclusive for GFR (MD -8.07 mL/min, 95% CI -18.57 to 2.43), and variable for graft loss, precluding meta-analysis. In direct comparison with CCB, ACEi decreased GFR (MD -11.48 mL/min, 95% CI -5.75 to -7.21), proteinuria (MD -0.28 g/24 h, 95% CI -0.47 to -0.10), haemoglobin (MD -12.96 g/L, 95% CI -5.72 to -10.21) and increased hyperkalaemia (RR 3.74, 95% CI 1.89 to 7.43). Graft loss data were inconclusive (RR 7.37, 95% CI 0.39 to 140.35). Other drug comparisons were compared in small numbers of participants and studies.

AUTHORS' CONCLUSIONS

These data suggest that CCB may be preferred as first line agents for hypertensive kidney transplant recipients. ACEi have some detrimental effects in kidney transplant recipients. More high quality studies reporting patient centred outcomes are required.

Renin-angiotensin system polymorphisms and hemoglobin level in renal allografts: a comparative study between losartan and enalapril

INTRODUCTION

In this study, hemoglobin (Hb) concentrations secondary to enalapril (E) or losartan (L) therapy were evaluated with respect to renin-angiotensin system (RAS) polymorphisms in renal transplant recipients.

MATERIALS AND METHODS

After determination of RAS polymorphisms [angiotensin-converting enzyme (DD, non-DD), angiotensinogen (TT, non-TT), and angiotensin receptor type 1 (CC, non-CC)] by polymerase chain reaction, 70 renal transplant recipients were recruited to four groups randomly: first and second groups were treated with E (10 mg/d, 15 patients) and L (50 mg/d, 20 patients) alone, respectively. The third group received E+L (10 mg/d + 50 mg/d, 13 patients) and the fourth group (22 patients) received no medication. The treatment protocol was followed for 16 weeks. Complete blood counts were checked before treatment and every 2 months. P<.05 was considered to indicate statistical significance.

RESULTS

Treatment for 4 months decreased the Hb level in the E+L (14.15 +/- 0.94 to 12.06 +/- 0.66 g/dL, P=.000), E (14.00 +/- 0.86 to 13.11 +/- 0.82 g/dL, P=.02), and L (14.12 +/- 0.90 to 12.10 +/- 2.35 g/dL, P=.01) groups, but not in the control group (13.55 +/- 0.70 to 13.36 +/- 0.69 g/dL, P>.05). None of these regimens showed greater Hb reduction than the others (P>.05). None of the RAS polymorphisms predicted the intensity of the reduced Hb according to the type of treatment (P>.05). Any other sets of RAS polymorphisms (alone or together) did not impact on Hb levels pre- or post-intervention (P>.05).

CONCLUSION

Our findings suggest that low dosages of E and/or L decrease Hb levels regardless of the RAS polymorphisms.

Anemia Due to Losartan in Hypertensive Renal Transplant Recipients Without Posttransplant Erythrocytosis

Losartan is a safe, effective long-term treatment for hypertension or posttransplant erythrocytosis (PTE) in renal transplant recipients. There were only a few studies in patients without PTE and their results were different. Starting from week 6 and continuing to the week 12 we observed a decrease in hemoglobin (Hb) and hematocrit (Hct) levels in patients without PTE. Anemia developed in 42.8% of the patients, and Hb levels increased after the withdrawal of losartan treatment. There was a significant decrease in Hct levels beginning from week 3 when compared with the control group. Our study suggests that losartan therapy can decrease Hb beyond its antihypertensive efficacy. Based on the capacity of losartan to decrease Hb and Hct, this drug should be carefully used in patients with preexistent anemia or low Hb levels.

Angiotensin-Converting enzyme gene polymorphism significantly affects renal posttransplantation erythrocytosis

Posttransplantation erythrocytosis (PE) is a frequent problem in renal transplant patients. The pathogenesis and mechanisms of both the problem and therapy strategy are unknown. Since ACE and angiotensin 2 receptor inhibitors have been used to successfully manage PE, we speculated a relation between gene polymorphisms and this complication. Ninety-six ( 30 women, 66 men, age 34.4 +/- 11.0 years) renal transplant patients evaluated retrospectively, for gene polymorphisms of ACE, angiotensinogen, angiotensin 1 and 2 receptors (ATR1 and ATR2), as well as endothelial nitric oxide synthase (ecNOS). They were divided into two groups; patients with versus without PE, which was defined as >15 g/dL hemoglobin levels during the first year after renal transplantation. PE was found to be significantly more prevalent among D/D than I/I gene polymorphism of ACE genes (P <.04). The distribution of D/D, I/D, and I/I polymorphisms were 39.1%, 45.9%, and 7.6%, respectively. There was no difference between D/D and I/D polymorphisms. Comparing the I/D and I/I polymorphisms showed PE to be statistically more prevalent in the I/D polymorphism (P <.01). Logistic regression analysis revealed that D/D and I/D polymorphisms were significant risk factors for PE (P <.05, RR = 7.714 and P <.03, RR = 10.199, respectively). While previous studies revealed a relation between angiotensin II and PE, our study discovered the contribution of ACE gene polymorphism.

Angiotensin-converting enzyme genotype is a predictive factor in the peak panel-reactive antibody response

The presence of a high panel-reactive antibody (PRA) level represents an independent risk factor for early graft failure and chronic allograft dysfunction. It has also been reported that patients with the ACE-DD and AGT-AA genotypes display poorer chronic allograft function. We investigated the effects of gene polymorphisms of the renin angiotensin system (RAS) on anti-HLA antibody production among renal transplant candidates. Genotyping was performed on 133 dialysis patients for the ACE (I/D) and AGT (M235T) as well as the type 1 (A1166C) and type 2 (A1223G) angiotensin II receptor genes. Patients with a peak PRA >/= 30% were considered to be positive for anti-HLA antibody (40.6% of 133 patients). Genetic polymorphisms of the RAS were not associated with anti-HLA antibody production at this PRA level. Another analysis comparing the 29 patients with a peak PRA >/=50% with the 104 patients with a peak PRA <50% showed that previous transplants, the presence of ACE-DD genotype, history of blood transfusions, and dialysis duration were all associated with the high levels of antibody production by univariant analysis. A multivariate analysis using a logistic regression model revealed previous transplants, the presence of ACE-DD genotype, and history of blood transfusions to be predictors of anti-HLA antibody production. The ACE-DD genotype is an important risk factor for higher PRA levels. This study suggests that genetic control of RAS activity correlates with production of anti-HLA antibodies, possibly explaining the relationship to chronic allograft outcome.

Use of candesartan cilexetil decreases proteinuria in renal transplant patients with chronic allograft dysfunction

BACKGROUND

Posttransplant proteinuria and hypertension are difficult to treat after renal transplantation. Therefore, we examined whether candesartan cilexetil is effective in reducing urinary protein excretion or in controlling hypertension in patients with renal allograft dysfunction.

METHODS

Sixty-two renal transplant recipients with proteinuria were enrolled in this study. They underwent kidney transplantation under cyclosporine or tacrolimus immunosuppression between February 1983 and December 1998. Causes of proteinuria were chronic rejection in 28, glomerulonephritis in 16, cyclosporine or tacrolimus nephrotoxicity in 9, and unknown in 9 recipients. The dose of candesartan cilexetil ranged from 4 to 12 mg/day. Eleven patients with proteinuria who had not been treated with candesartan cilexetil constituted a matched control population.

RESULTS

Hypertension was well controlled by administration of candesartan cilexetil. Both systolic blood pressure and diastolic blood pressure significantly decreased from 141.7+/-14.8 mm Hg to 118.7+/-11.9 mm Hg and 121.2+/-11.6 mm Hg, and from 89.0+/-13.0 mm Hg to 72.0+/-10.4 mm Hg and 74.9+/-9.4 mm Hg, at 2 months and 1 year after administration, respectively. Urinary protein excretion was reduced from 0.93+/-1.2 g/day to 0.34+/-0.7 g/day and 0.43+/-1.2 g/day at 2 months and 1 year after administration, respectively. The levels of creatinine clearance were 55.7+/-28.9 mL/min before treatment, 50.9+/-24.8 mL/min at 2 months, and 52.6+/-24.8 mL/min at 1 year after treatment, respectively. There was no clinically significant difference between them. Regarding the calcineurin inhibitor levels, there was no significant difference between the levels before and 1 year after treatment. There was a significant difference in all examinations (systolic blood pressure, diastolic blood pressure, proteinuria, and renal function) between the patients with and without candesartan at 1 year after treatment. No significant adverse effects occurred.

CONCLUSIONS

Candesartan cilexetil can effectively control hypertension and proteinuria without deterioration in renal allograft function. These data suggest that treatment with candesartan cilexetil may be useful for maintaining long-term renal allograft function.

Routine renin-angiotensin system blockade in renal transplantation?

There is ample evidence to support the recommendation of renin-angiotensin system blockade therapy as the standard of care for strategies aimed at preserving renal function in chronic renal disease. Nevertheless, despite the well established antihypertensive effects of these drugs, the use of renin-angiotensin system blockers in renal transplantation has been quite limited so far, nephrologists being afraid of the possibility of inducing renal insufficiency in patients with a single kidney transplant. However, current knowledge of the ability of these agents to control blood pressure and urinary protein excretion, as well as post-transplant erythrocytosis, effectively in kidney transplant recipients suggests that it is now time to apply renin-angiotensin system blockers to the field of renal transplantation.

Comparison of the effects of enalapril and losartan on posttransplantation erythrocytosis in renal transplant recipients: prospective randomized study

BACKGROUND

The aim of this prospective randomized study was to compare the safety and efficacy of enalapril (E) and losartan (L) in the treatment of posttransplantation erythrocytosis and the effect of the ACE genotype on response to therapy.

METHODS

Twenty-seven (24 male and 3 female, mean age 34+/-8 years) renal transplant recipients with erythrocytosis were treated either with E (15 patients) (10 mg/day) or L (12 patients) (50 mg/day) for 8 weeks.

RESULTS

The hemoglobin levels were significantly decreased in the L (17.1+/-0.7 to 15.9+/-1.3 g/dl, P=0.01) and E groups (17.4+/-1.1 to 14.9+/-2.2 g/dl, P=0.001). Among the responders who discontinued treatment, there was a trend for longer time to relapse in the L group (7.38+/-3.75 months; 95% confidence interval: 0.03-14.7) compared with the E group (2.75+/-0.70 (95% confidence interval: 1.37-4.13) (P=0.11). Decrease in hemoglobin was more prominent with E compared with L (-3.26+/-0.65 vs. -1.70+/-0.39 g/dl, P=0.05). Decrease in hemoglobin levels between DD and non-DD genotype groups was similar (-2.0+/-1.5 vs. -1.7+/-2.3 g/dl, P=0.69).

CONCLUSIONS

Enalapril caused a greater decrease but faster relapse in hemoglobin levels compared with losartan in patients with posttransplantation erythrocytosis. The DD type polymorphism had no effect on response.