Use of atorvastatin in hyperlipidemic hypertensive renal transplant recipients

Promoting cardiovascular health post-transplant through early diagnosis and adequate management of hypertension and dyslipidemia

Despite correction of underlying solid organ failure by transplantation, pediatric transplant recipients still have increased mortality rates compared to the general pediatric population, in part due to increased cardiovascular risk. In particular, pediatric kidney and non-kidney transplant recipients with chronic kidney disease have significant cardiovascular risk that worsens with declining kidney function. Biomarkers associated with future cardiovascular risk such as casual and ambulatory hypertension, dyslipidemia, vascular stiffness and calcification, and left ventricular hypertrophy can be detected throughout the post-transplant period and in patients with stable kidney function. Among these, hypertension and dyslipidemia are two potentially modifiable cardiovascular risk factors that are highly prevalent in kidney and non-kidney pediatric transplant recipients. Standardized approaches to appropriate BP measurement and lipid monitoring are needed to detect and address these risk factors in a timely fashion. To achieve sustained improvement in cardiovascular health, clinicians should partner with patients and their caregivers to address these and other risk factors with a combined approach that integrates pharmacologic with non-pharmacologic approaches. This review outlines the scope and impact of hypertension and dyslipidemia in pediatric transplant recipients, with a particular focus on pediatric kidney transplantation given the high burden of chronic kidney disease-associated cardiovascular risk. We also review the current published guidelines for monitoring and managing abnormalities in blood pressure and lipids, highlighting the important role of therapeutic lifestyle changes in concert with antihypertensive and lipid-lowering medications.

Phase I/IIa Trial of Atorvastatin in Patients with Acute Kawasaki Disease with Coronary Artery Aneurysm

OBJECTIVES

To determine the safety, tolerability, pharmacokinetics, and immunomodulatory effects of a 6-week course of atorvastatin in patients with acute Kawasaki disease with coronary artery (CA) aneurysm (CAA).

STUDY DESIGN

This was a Phase I/IIa 2-center dose-escalation study of atorvastatin (0.125-0.75 mg/kg/day) in 34 patients with Kawasaki disease (aged 2-17 years) with echocardiographic evidence of CAA. We measured levels of the brain metabolite 24(S)-hydroxycholesterol (24-OHC), serum lipids, acute-phase reactants, liver enzymes, and creatine phosphokinase; peripheral blood mononuclear cell populations; and CA internal diameter normalized for body surface area before atorvastatin treatment and at 2 and 6 weeks after initiation of atorvastatin treatment.

RESULTS

A 6-week course of up to 0.75 mg/kg/day of atorvastatin was well tolerated by the 34 subjects (median age, 5.3 years; IQR, 2.6-6.4 years), with no serious adverse events attributable to the study drug. The areas under the curve for atorvastatin and its metabolite were larger in the study subjects compared with those reported in adults, suggesting a slower rate of metabolism in children. The 24-OHC levels were similar between the atorvastatin-treated subjects and matched controls.

CONCLUSIONS

Atorvastatin was safe and well tolerated in our cohort of children with acute Kawasaki disease and CAA. A Phase III efficacy trial is warranted in this patient population, which may benefit from the known anti-inflammatory and immunomodulatory effects of this drug.

Unusual pattern of dyslipidemia in children receiving steroid minimization immunosuppression after renal transplantation

BACKGROUND AND OBJECTIVES

Corticosteroids are an important contributor to posttransplant hyperlipidemia. Since 2004, we have used a steroid minimization immunosuppression protocol. This study investigated the effect of steroid minimization on dyslipidemia in pediatric renal allograft recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Children (<18 years) who underwent renal transplants at our center from January 2001 to January 2008 were studied. Data analyzed included age, gender, race, body mass index, cholesterol, triglyceride, LDL cholesterol, HDL cholesterol, and steroid dose. Data between the cohorts receiving maintenance steroids and steroid-minimization were compared using multivariable analyses. The primary outcome measures were the prevalence of, and the effect of steroid use, on dyslipidemia.

RESULTS

Twenty-nine patients were studied. Sixteen were receiving maintenance steroids, and 13 were on a steroid minimization regimen. Mixed effects analysis of covariance models demonstrated that at 1 month, children receiving maintenance steroids had higher cholesterol compared with the steroid minimization group. Statistically significant differences in total cholesterol were not seen at other time points. Similar findings were noted for the LDL cholesterol, LDL/HDL, and cholesterol/HDL ratios. At 1 month, the serum HDL cholesterol was substantially lower in the steroid minimization group. Differences in the HDL cholesterol levels remained significant throughout the first year.

CONCLUSIONS

Steroid use is a significant independent risk factor for hypercholesterolemia during the first post-transplant month. The significance of lower HDL cholesterol among patients receiving steroid minimization needs further study and may be cause for concern.

Statins in nephrotic syndrome: a new weapon against tissue injury

The nephrotic syndrome is characterized by metabolic disorders leading to an increase in circulating lipoproteins levels. Hypertriglyceridemia and hypercholesterolemia in this case may depend on a reduction in triglyceride-rich lipoproteins catabolism and on an increase in hepatic synthesis of Apo B-containing lipoproteins. These alterations are the starting point of a self-maintaining mechanism, which can accelerate the progression of chronic renal failure. Indeed, hyperlipidemia can affect renal function, increase proteinuria and speed glomerulosclerosis, thus determining a higher risk of progression to dialysis. 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is the rate-limiting enzyme in cholesterol synthesis from mevalonate and its inhibitors, or statins, can therefore interfere with the above-mentioned consequences of hyperlipidemia. Statins are already well known for their effectiveness on primary cardiovascular prevention, which cannot be explained only through their hypolipemic effect. As far as kidney diseases are concerned, statin therapy has been shown to prevent creatinine clearance decline and to slow renal function loss, particularly in case of proteinuria, and its favorable effect may depend only partially on the attenuation of hyperlipidemia. Statins may therefore confer tissue protection through lipid-independent mechanisms, which can be triggered by other mediators, such as angiotensin receptor blockers. Possible pathways for the protective action of statins, other than any hypocholesterolemic effect, are: cellular apoptosis/proliferation balance, inflammatory cytokines production, and signal transduction regulation. Statins also play a role in the regulation of the inflammatory and immune response, coagulation process, bone turnover, neovascularization, vascular tone, and arterial pressure. In this study, we would like to provide scientific evidences for the pleiotropic effects of statins, which could be the starting point for the development of new therapeutical strategies in different clinical areas.

Atorvastatin affects interleukin-2 signaling by altering the lipid raft enrichment of the interleukin-2 receptor beta chain

Although the immunomodulatory properties of statins are in part independent of their lipid-lowering effects, cholesterol is a major component of lipid rafts. We therefore studied the effects of atorvastatin (AS) on the raft enrichment of the interleukin-2 receptor (IL-2R) beta chain previously described by us and on early IL-2R signaling events in activated human T cells. We found that concomitant AS exposure during a 3-day stimulation with phytohemagglutinin (PHA) attenuates activation-associated events, such as the enhanced surface expression of the raft marker GM-1 and the induced expression of the activation marker CD25 (the IL-2R alpha chain). In contrast, brief AS treatment after PHA stimulation increased GM-1 surface expression and virtually abolished the selective raft enrichment of the IL-2R beta chain. Although this AS-associated increase in GM-1 expression resembled that seen in the presence of the raft-disrupting cholesterol chelator methyl-beta-cyclodextrin (MBCD), the two agents had contrasting effects on the tyrosine phosphorylation of the IL-2R beta chain by exogenous IL-2: MBCD essentially abolished this event, whereas AS tended to enhance it and shifted its occurrence out of rafts. We conclude that AS affects IL-2R signaling by altering the raft enrichment of the IL-2R beta chain and propose that this effect is one mechanism underlying the immunomodulatory properties of statins.

Prospective monitoring of lipid profiles in children receiving pravastatin preemptively after renal transplantation

Hyperlipidemia is common after renal transplantation (Tx) and contributes to the increased cardiovascular morbidity seen in the post-transplant period. Limited data are available on the utility of the statins in children after renal Tx. This 12-month prospective study was undertaken to determine the efficacy of pravastatin in reducing dyslipidemia after renal Tx in children and to determine predictors of dyslipidemia after Tx. From August 2001 to April 2004, all 17 newly transplanted pediatric renal transplant recipients at our center were preemptively treated with pravastatin from the immediate post-transplant period. Fasting lipid profiles were obtained at 1, 3, 6 and 12 months after Tx. Trends in the lipid profile were analyzed using the repeated measures general linear model (GLM). A historical cohort of pediatric renal-transplant recipients not treated with pravastatin was used as the control population. The mixed effects GLM was used for multivariable logistic regression analyses to determine the independent effect of age, pretransplant cholesterol (Chol), body mass index (BMI), creatinine clearance (CrCl), and corticosteroid and tacrolimus doses on the development of dyslipidemia. The mean age of the children at Tx was 8.7 yr. The GLM analysis showed that with time, there was a significant decline in the total Chol, serum triglyceride (TG), LDL and also HDL-Chol (p-value <0.05 for each). Compared with the controls, the mean serum Chol was lower at all time points post-transplant in the treated patients. However, despite treatment, the prevalence of hypercholesterolemia increased from 31% pretransplant to 53% at 1-month, but declined thereafter to 6% at 3 and 6 months and 0% at 1 yr. Multivariable regression analyses showed the prednisone dose, pretransplant Chol and age to be the most important risk factors for the development of dyslipidemia. No child developed complications related to therapy. In summary, pravastatin is safe in the post-transplant period in children and reduces serum Chol, LDL-Chol and TG. An unexpected finding in our study was the decline in HDL-Chol after Tx. Whether the preemptive use of the statins will result in lower cardiovascular morbidity, especially considering the concomitant reduction in HDL-Chol remains to be determined.

Twenty-four-hour ambulatory blood pressure profiles in liver transplant recipients

Twenty-four-hour ambulatory blood pressure monitoring (ABPM) has proven to have better reproducibility than office blood pressure (BP) and is increasingly used for the study of hypertension in children and adolescents. The aim of our study was to assess 24-h BP profiles and to compare the results of office BP measurements with ABPM in stable liver transplant recipients transplanted before the age of 18 yr. ABPM was performed in 29 patients (nine males, 20 females), aged 3.9-24.8 yr (median 10.8 yr). The investigation was conducted 1.1-11.5 yr (median 5.1 yr) following transplantation. ABPM confirmed hypertension in one out of three office hypertensive patients. Seven patients (24%), whose office BP recordings were within the normotensive range, were reclassified as hypertensive. Non-dippers (n = 17), arbitrarily defined as patients with less than 10% nocturnal fall in BP, were similarly distributed among patients with ambulatory normotension and ambulatory hypertension (chi(2), p = 0.79). In addition, non-dippers showed a negative correlation between 24-h total urinary albumin excretion and both systolic and diastolic nocturnal decline in BP (Rho = -0.48, p < 0.05 and Rho = -0.86, p < 0.01, respectively). Our study found office BP readings to be poorly representative of 24-h BP profile. Larger studies are needed to confirm our observations as well as to determine whether routine BP measurements in the follow-up of paediatric liver transplant recipients should be based solely on office BP.

Risk factors for cardiovascular disease in pediatric renal transplant recipients

About 1,000 children develop end-stage renal disease (ESRD) each year in the United States and about 5,000 children are currently receiving dialysis. Children who develop ESRD are eligible to receive renal replacement therapy, including renal transplantation. There are inherent risks associated with transplantation, including renal insufficiency, infections, post-transplant lymphoproliferative disorder, and cardiovascular disease (CVD). Potential risk factors for CVD in pediatric renal transplant recipients include renal insufficiency, hyperlipidemia, hyperhomocysteinemia, inflammation, malnutrition, anemia, and hyperglycemia/insulin resistance. Despite evidence that many children may possess various risk factors for CVD post-renal transplantation, there are very few studies that have attempted to assess the link between these risk factors and CVD in pediatric renal transplant recipients.

Analysis of blood pressure in children and adolescents reporting siesta during ambulatory blood pressure monitoring

BACKGROUND

In adults, a siesta yields a blood pressure profile similar to that seen in nocturnal sleep. It is therefore stressed that siestas should not be included in daytime blood pressure measurement.

OBJECTIVES

To evaluate blood pressure profiles in pediatric and adolescent patients who reported a siesta during 24 h ambulatory blood pressure monitoring (ABPM).

METHODS

Patients' diaries of actual sleep times were used to determine the periods of sleep (night-time and siesta) and daytime wakefulness. Ambulatory systolic and/or diastolic daytime and/or night-time hypertension was determined by comparing patients' measurements with normal values taken from published standards for healthy children and adolescents. Data obtained from 12 patients with ambulatory normotension and 12 patients with ambulatory hypertension, who were referred for an evaluation of hypertension or management of known hypertension, were analysed separately.

RESULTS

Mean systolic (SBP) and diastolic (DBP) blood pressure values during the daytime awake period were significantly higher than the mean values for the period of daytime, including the siesta, both in patients with ambulatory normotension and in those with ambulatory hypertension (P<0.001 and P<0.01 for SBP and DBP, and P<0.001 and P<0.001 for SBP and DBP, respectively). The percentage night-time falls in SBP and DBP were 12.9+/-0.5 and 19.1+/-1.4 in patients with ambulatory normotension, and 7.1+/-1.5 and 12.9+/-2.2 in patients with ambulatory hypertension. These values were significantly higher when the siesta was excluded from the analysis in both groups (13.9+/-0.5% and 20.7+/-1.5%, P<0.001 and P<0.01 for SBP and DBP in patients with ambulatory normotension; 8+/-1.6% and 14.8+/-2.4%, P<0.001 and P<0.001 for SBP and DBP in patients with ambulatory hypertension, respectively).

CONCLUSIONS

By ignoring the effect of the siesta, both the calculation of daytime blood pressure values and the analysis of day-night variability in children and adolescents undergoing ABPM may be erroneously interpreted.