Effect of nitrendipine on renal function in renal-transplant patients treated with cyclosporin: a randomised trial

Peritoneal Dialysis in the Patient with a Failing Renal Allograft

Background

Patients returning to dialysis treatment after a period with a functioning allograft represent a special case in the integrated care model of renal replacement therapy. They are known to nephrologists— and thus are ideal candidates for a timely commencement of dialysis—but they have had time to accrue additional cardiovascular risk. Furthermore, they have been exposed to prolonged immunosuppression.

Purpose

The present study aimed to establish the clinical outcomes of patients returning to peritoneal dialysis (PD) with failing allografts [survival, technique survival, longitudinal residual renal function (Kt/VR), peritoneal membrane function (solute transport), and plasma albumin] and to compare those outcomes with outcomes in new, contemporary patients.

Setting

The study was conducted in a single center where prospective collection of data now known to be important in determining outcome on peritoneal dialysis (age, comorbidity, albumin, Kt/VR, and solute transport) has been performed since 1989.

Methods

All patients commencing PD between 1989 and 2001 after failure of an allograft that had functioned for more than 6 months were identified. Outcomes in that group were compared to outcomes in all new PD patients and in all dialysis patients with failed grafts who were returning to hemodialysis (HD) in the same period.

Results

The study identified 45 patients with failed allografts: 28 were commencing PD treatment, and 17 were commencing HD treatment. Those patients were significantly younger than the 469 new patients commencing PD [FailedTx→ PD 41.2 years, FailedTx→ HD 38.9 years, NewPD 54.7 years; analysis of variance (ANOVA): p < 0.001]. We saw no significant difference in the survival of failed transplant patients commencing PD as compared with those commencing HD (log rank: p = 0.11). Kaplan–Meier plots of patient survival were better for failed transplant patients as compared with all new PD patients. When corrected using Cox regression, the survival advantage was seen to be due to age and comorbidity at start of PD. Pure technique failure (excluding death) was not different between the groups. Compared with all new PD patients, patients with failed allografts had similar longitudinal plasma albumin and a tendency toward an earlier increase in solute transport, but a more rapid loss of Kt/VR, ( p < 0.05 at 6 – 48 months).

Conclusions

Peritoneal dialysis would appear to be a good option for patients with failing allografts. Co-morbidity is the predominant determinant of survival. That finding underlines the need for attention to factors that might prevent accrual of cardiovascular risk during the post-transplantation period. The earlier loss of Kt/VR in those patients might be prevented by developing strategies of continued immunosuppression after commencement of dialysis, although infection risk is an important issue.

Comparative effectiveness of different antihypertensive agents in kidney transplantation: a systematic review and meta-analysis

Background

We conducted a systematic review and meta-analysis to compare benefits and harms of different antihypertensive drug classes in kidney transplant recipients, as post-transplant hypertension (HTN) associates with increased cardiovascular (CV) morbidity and mortality.

Methods

The Ovid-MEDLINE, PubMed and CENTRAL databases were searched for randomized controlled trials (RCTs) comparing all main antihypertensive agents versus placebo/no treatment, routine treatment.

Results

The search identified 71 RCTs. Calcium channel blockers (CCBs) (26 trials) reduced the risk for graft loss {risk ratio [RR] 0.58 [95% confidence interval (CI) 0.38–0.89]}, increased glomerular filtration rate (GFR) [mean difference (MD) 3.08 mL/min (95% CI 0.38–5.78)] and reduced blood pressure (BP). Angiotensin-converting enzyme inhibitors (ACEIs) (13 trials) reduced the risk for graft loss [RR 0.62 (95% CI 0.40–0.96)] but decreased renal function and increased the risk for hyperkalaemia. Angiotensin receptor blockers (ARBs) (10 trials) did not modify the risk of death, graft loss and non-fatal CV events and increased the risk for hyperkalaemia. When pooling ACEI and ARB data, the risk for graft failure was lower in renin–angiotensin system (RAS) blockade as compared with control treatments. In direct comparison with ACEIs or ARBs (11 trials), CCBs increased GFR [MD 11.07 mL/min (95% CI 6.04–16.09)] and reduced potassium levels but were not more effective in reducing BP. There are few available data on mortality, graft loss and rejection. Very few studies performed comparisons with other active drugs.

Conclusions

CCBs could be the preferred first-step antihypertensive agents in kidney transplant patients, as they improve graft function and reduce graft loss. No definite patient or graft survival benefits were associated with RAS inhibitor use over conventional treatment.

Cardiovascular morbidity and mortality after kidney transplantation

Kidney transplantation is the optimal treatment for patients with end stage renal disease (ESRD) who would otherwise require dialysis. Patients with ESRD are at dramatically increased cardiovascular (CV) risk compared with the general population. As well as improving quality of life, successful transplantation accords major benefits by reducing CV risk in these patients. Worldwide, cardiovascular disease remains the leading cause of death with a functioning graft and therefore is a leading cause of graft failure. This review focuses on the mechanisms underpinning excess CV morbidity and mortality and current evidence for improving CV risk in kidney transplant recipients. Conventional CV risk factors such as hypertension, diabetes mellitus, dyslipidaemia and pre-existing ischaemic heart disease are all highly prevalent in this group. In addition, kidney transplant recipients exhibit a number of risk factors associated with pre-existing renal disease. Furthermore, complications specific to transplantation may ensue including reduced graft function, side effects of immunosuppression and post-transplantation diabetes mellitus. Strategies to improve CV outcomes post-transplantation may include pharmacological intervention including lipid-lowering or antihypertensive therapy, optimization of graft function, lifestyle intervention and personalizing immunosuppression to the individual patients risk profile.

Acute effects of calcineurin inhibitors on kidney allograft microperfusion visualized by contrast-enhanced sonography

BACKGROUND

Calcineurin inhibitors induce detrimental vascular remodeling, which may be one cause of chronic allograft failure. Real-time contrast-enhanced sonography (CES) is a relatively new technique in providing quantitative information on microvascular tissue perfusion in kidney allografts in more detail. The purpose of the study was to explore whether acute changes of kidney allograft microperfusion due to the administration of cyclosporine A (CsA) and tacrolimus (Tac) can be evidenced using real-time CES.

METHODS

In an explorative single-center clinical trial, renal parenchymal tissue perfusion of 32 stable kidney allograft recipients was evaluated with CES before and 2 hr after the intake of CsA or Tac. In addition to laboratory and clinical parameters, Doppler indices and estimated glomerular filtration rate were measured.

RESULTS

Although systolic and diastolic blood pressure and color Doppler indices did not significantly differ, there was a significant decrease of renal blood flow 2 hr after the intake of CsA compared with baseline (4.78±2.31 dB/s, 49%, respectively). In contrast, kidney allograft microperfusion was neither significantly reduced in patients receiving CsA paralleled by calcium channel blockers nor significantly reduced in patients receiving Tac. Furthermore, there was a significant correlation between renal blood flow obtained before drug administration and kidney function.

CONCLUSIONS

CES revealed a 49% reduction of kidney allograft microperfusion 2 hr after the intake of CsA, which might be abrogated by calcium channel blockers. In comparison to CsA, Tac did not result in a significant decrease of kidney blood flow.

Combination of nifedipine and subtherapeutic dose of cyclosporin additively suppresses mononuclear cells activation of patients with rheumatoid arthritis and normal individuals via Ca(2+) -calcineurin-nuclear factor of activated T cells pathway

Abnormal Ca(2+) -mediated signalling contributes to the pathogenesis of rheumatoid arthritis (RA). However, the potential implication of calcium channel blocker in RA remained unknown. We hypothesized that nifedipine, an L-type calcium channel blocker, combined with a calcineurin inhibitor, could suppress T cell activation via targeting different level of the Ca(2+) signalling pathway. The percentage of activated T cells and the apoptotic rate of mononuclear cells (MNCs) was measured by flow cytometry. The MNC viability, cytokine production, cytosolic Ca(2+) level and activity of the nuclear factor of activated T cells (NFAT) were measured by enzyme-linked immunosorbent assay (ELISA). The NFAT-regulated gene expression, including interleukin (IL)-2, interferon (IFN)-γ and granulocyte-macrophage colony-stimulating factor (GM-CSF), was measured by real-time polymerase chain reaction (PCR). We found that the percentage of activated T cells in anti-CD3 + anti-CD28-activated MNC was higher in RA patients. High doses of nifedipine (50 µM) increased MNCs apoptosis, inhibited T cell activation and decreased T helper type 2 (Th1) (IFN-γ)/Th2 (IL-10) cytokine production in both groups. The Ca(2+) influx was lower in anti-CD3 + anti-CD28-activated MNC from RA patients than healthy volunteers and suppressed by nifedipine. When combined with a subtherapeutic dose (50 ng/ml) of cyclosporin, 1 µM nifedipine suppressed the percentage of activated T cells in both groups. Moreover, this combination suppressed more IFN-γ secretion and NFAT-regulated gene (GM-CSF and IFN-γ) expression in RA-MNCs than normal MNCs via decreasing the activity of NFATc1. In conclusion, we found that L-type Ca(2+) channel blockers and subtherapeutic doses of cyclosporin act additively to suppress the Ca(2+) -calcineurin-NFAT signalling pathway, leading to inhibition of T cell activity. We propose that this combination may become a potential treatment of RA.

The management of hypertensive emergencies in children after stem cell transplantation

AIM OF THE REVIEW

This work presents a short overview on the available data about drugs that are currently used to treat hypertensive emergencies in children with a focus on incidents after stem cell transplantation. It shows that the pediatric use of all hypotensive agents appears to be mainly based on personal experience of the attending physicians rather than on convincing clinical trials.

METHOD

A literature search was performed in MEDLINE, through PubMed, using the medical subject headings (MeSH) hypertensive emergencies, nifedipine, nicardipine, and children. Further articles were identified by checking cross-references of articles and books.

RESULTS

Hypertensive emergencies in children after stem cell transplantation usually have a renal etiology, because of the treatment with the calcineurin inhibitors cyclosporine and tacrolimus. In these severe cases an immediate action is necessary to avoid possible appearance or exacerbation of endorgan damage. Because of their mechanism of action and a potential nephroprotective effect calcium channel blockers may be particularly suitable in cases of hypertensive emergencies. An intravenous application of nifedipine may compensate the difficulties of accurate dosing, but keeping in mind possible severe side effects and the lack of published experience its use in children is at least questionable. Nicardipine appears to be the hypotensive agent of first choice. In adults, the treatment of hypertensive emergencies with intravenous nicardipine is well-documented, but for an evaluation of safety in pediatric use, the published studies and case reports appear to be barely adequate.

CONCLUSION

The actual treatment approaches vary widely, demonstrating the lack of hard science on which current treatment of hypertensive emergencies in children is based. The hypotensive agent for the individual situation should be chosen considering the properties, side effects, the limited experiences with its use and the patient's anamnesis.

Hypertension in kidney transplant recipients

Arterial hypertension is frequently observed in renal transplant recipients. Its pathogenesis is multifactorial in most cases. Calcineurin inhibitors (CNI) can increase peripheral vascular resistance by inducing arteriolar vasoconstriction and can cause extracellular fluid expansion by reducing the glomerular filtration rate (GFR), activating the renin-angiotensin system (RAS), and by inactivating the atrial natriuretic peptide. Glucocorticoids can impair urinary water and salt excretion. Poor graft function can lead to increased extracellular volume and inappropriate production of renin. Native kidneys, older age of the donor and transplant renal artery stenosis (TRAS) may also contribute to the development of hypertension. Arterial hypertension not only can increases the risk for cardiovascular events but can also deteriorate renal allograft function. A number of studies have shown that the higher the levels of blood pressure are, the higher is the risk of graft failure. On the other hand, a good control of blood pressure may prevent many cardiovascular and renal complications. Appropriate lifestyle modification is the first step for treating hypertension. Calcium channel blockers (CCB) and renin-angiotensin system (RAS) inhibitors are the most frequently used antihypertensive agents, but in many cases, a combination of these and other drugs is required to obtain good control of hypertension.

Primary care of the transplant patient

A total of 153,245 patients are living with a solid organ transplant in the US. In addition, patients are experiencing high 5-year survival rates after transplantation. Thus, primary care physicians will be caring for transplanted patients. The aim of this review is to update primary care physicians on chronic diseases, screening for malignancy, immunizations, and contraception in the transplant patient. Several studies on the treatment of hypertension and hyperlipidemia demonstrate that most agents used to treat the general population also can be used to treat transplant recipients. Little information exists on the medical management of diabetes in the transplant population, but experts in the area believe that the treatment of diabetes should be similar. Transplant recipients are at increased risk for all malignancies. Aggressive screening should be employed for all cancers with a proven screening benefit. Killed immunizations are safe for the transplant population, but live virus vaccines should be avoided. Women of childbearing age should be counseled about the impact of immunosuppressants on the efficacy and side effects of contraception.

The pathogenesis and treatment of chronic allograft nephropathy

Despite improvements in immunosuppressive therapy, long-term allograft survival after kidney transplantation remains as low as 50%. Chronic allograft nephropathy (CAN) is a major cause of late graft loss in renal transplant recipients. The histopathologic signs of CAN-interstitial fibrosis, tubular atrophy, glomerulopathy and vasculopathy-are nonspecific; therefore, the 2007 Banff classification dispensed with the term CAN in favor of 'interstitial fibrosis and tubular atrophy without evidence of any specific etiology'. In this Review, however, the term CAN is used to describe a clinical syndrome that is characterized by progressive decline in renal function from 3 months after transplantation, accompanied by the development of proteinuria and hypertension. The pathogenesis of CAN is complex and incompletely understood, and involves several immunological and non-immunological factors. We discuss the contributory roles of acute rejection, donor age, anti-human-leukocyte-antigen antibodies, calcineurin inhibitor nephrotoxic effects, viral infection, hypertension and hyperlipidemia. The prevention and treatment of CAN needs multidisciplinary strategies. Early detection by means of protocol biopsy and calculation of glomerular filtration rate is the first step, followed by management of modifiable risk factors.

Antihypertensives for kidney transplant recipients: systematic review and meta-analysis of randomized controlled trials

In nontransplant populations, effects of different antihypertensive drug classes vary. Relative effects in kidney transplant recipients are uncertain. We performed a systematic review including random effects meta-analysis of randomized controlled trials, using Cochrane Collaboration methodology. We identified 60 trials, enrolling 3802 recipients. Twenty-nine trials (2262 patients) compared calcium channel blockers (CCB) with placebo or no treatment, 10 trials (445 patients) compared angiotensin-converting enzyme inhibitors (ACEi) with placebo or no treatment, and seven studies (405 patients) compared CCB with ACEi. CCB compared with placebo or no treatment (plus additional agents in either arm as required) reduced graft loss (risk ratio [RR] 0.75, 95% confidence intervals [CI] 0.57-0.99) and improved glomerular filtration rate (GFR; mean difference [MD] 4.5 mL/min, 95% CI 2.2-6.7). Data on ACEi versus placebo or no treatment were inconclusive for GFR (MD -8.1 mL/min, 95% CI -18.6-2.4) and inconsistent for graft loss, precluding meta-analysis. In direct comparison with CCB, ACEi decreased GFR (MD 11.5 mL/min, 95% CI 7.2-15.8), proteinuria (MD 0.28 g/day, 95% CI 0.10-0.47), hemoglobin (MD 11.5 g/L, 95% CI 7.2-15.8), and increased hyperkalemia (RR 3.7, 95% CI 1.9-7.7). Graft loss data were inconclusive (RR 7.4, 95% CI 0.4-140). These data suggest that CCB may be preferred as first-line agents for hypertensive kidney transplant recipients.

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.

Calcineurin inhibitor nephrotoxicity

The use of the calcineurin inhibitors cyclosporine and tacrolimus led to major advances in the field of transplantation, with excellent short-term outcome. However, the chronic nephrotoxicity of these drugs is the Achilles' heel of current immunosuppressive regimens. In this review, the authors summarize the clinical features and histologic appearance of both acute and chronic calcineurin inhibitor nephrotoxicity in renal and nonrenal transplantation, together with the pitfalls in its diagnosis. The authors also review the available literature on the physiologic and molecular mechanisms underlying acute and chronic calcineurin inhibitor nephrotoxicity, and demonstrate that its development is related to both reversible alterations and irreversible damage to all compartments of the kidneys, including glomeruli, arterioles, and tubulo-interstitium. The main question--whether nephrotoxicity is secondary to the actions of cyclosporine and tacrolimus on the calcineurin-NFAT pathway--remains largely unanswered. The authors critically review the current evidence relating systemic blood levels of cyclosporine and tacrolimus to calcineurin inhibitor nephrotoxicity, and summarize the data suggesting that local exposure to cyclosporine or tacrolimus could be more important than systemic exposure. Finally, other local susceptibility factors for calcineurin inhibitor nephrotoxicity are reviewed, including variability in P-glycoprotein and CYP3A4/5 expression or activity, older kidney age, salt depletion, the use of nonsteroidal anti-inflammatory drugs, and genetic polymorphisms in genes like TGF-beta and ACE. Better insight into the mechanisms underlying calcineurin inhibitor nephrotoxicity might pave the way toward more targeted therapy or prevention of calcineurin inhibitor nephrotoxicity.

[Current problems of kidney transplantation]

The long-term problems after kidney transplantation have changed considerably in recent years. While formerly immunosuppression and prevention of acute rejection were of prime concern, now attention focuses on chronic alterations of the transplanted organ and long-term survival of the patients. The transplantation procedure itself has evolved into a standardized technique with a high level of surgical quality. Problems involving organ preservation and ischemia/reperfusion damage also play a role, especially in view of chronic aspects. Monitoring of long-term complications should follow a program for the transplanted organ as well as a program for the patient. Monitoring kidney function should address the organ more precisely than has previously been the case. Serum creatinine level and proteinuria alone provide insufficient information and only change long after cellular deterioration has begun. Hence it is imperative that new testing methods be developed. One possibility is offered by protocol biopsies that allow histological and molecular analysis of the kidney at regular intervals. The patient programs concentrate on diagnostics and treatment of the cardiovascular diseases. Furthermore, the patients must be screened for occurrence of neoplasia. There are no prospective studies covering all cardiovascular risk factors after kidney transplantation. This pertains particularly to the subject of hypertension.

Late kidney allograft loss: what we know about it, and what we can do about it

Despite dramatic improvements in immunosuppression, late graft loss after kidney transplantation remains a common and difficult problem. Histologic evaluation may reveal changes related to BK polyomavirus infection, hypertension, or calcineurin inhibitor toxicity, which can help to guide therapy. The designation chronic allograft nephropathy should thus be reserved for biopsies with tubular atrophy and interstitial fibrosis without an apparent cause. Although the cause clearly includes both antigen-dependent and antigen-independent events, the approach remains largely to exclude immune mechanisms. Although this review discusses the potential contribution of antibody to chronic injury, it focuses on the basic elements of kidney injury, the role of parenchymal cells in promoting injury, and the proliferative and inflammatory responses that accompanying injury. Strategies to manage these recipients include close attention to accompanying hypertension, diabetes, and hyperlipidemia, as well as consideration for altering immunosuppression; however, therapies that limit epithelial-to-mesenchymal transition or directly block fibrosis pathways may reduce chronic allograft fibrosis and may prove to be useful. Understanding the basic pathogenesis sufficiently to allow early intervention may finally benefit patients who are at high risk for tubular atrophy and interstitial fibrosis and promote their long-term graft function.

Reducing the risks of cardiovascular disease in liver allograft recipients

Liver allograft recipients are at increased risk of death from cerebrovascular and cardiovascular disease. We propose the following strategy of risk-reduction, based on currently available literature. Lifestyle: standard advice should be given (avoidance of smoking, excess alcohol and obesity, adequate exercise, reduction of excess sodium intake). Hypertension: target blood pressure should be 140/90 mmHg or lower, but for those with diabetes or renal disease, 130/80 mmHg or lower. For patients without proteinuria, antihypertensive therapy should be initiated with a calcium channel blocker and for those with proteinuria, an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker. If monotherapy fails to achieve adequate response, calcium channel blockers and ACE-inhibitors or angiotensin II receptor blockers should be combined. If hypertension remains uncontrolled, an alpha-blocker may be added. Consideration should be given to changing immunosuppression and avoiding use of calcineurin inhibitors. Diabetes: recipients should be regularly screened for diabetes. For patients with new-onset diabetes after transplant, stepwise therapy should be guided by HbA1c concentrations, as with type II diabetes mellitus. Hyperlipidemia: annual screening of lipid profile should be undertaken, with treatment thresholds and targets based on those advocated for the high risk general population. Dietary intervention is appropriate for all patients. A statin should be considered as the first line treatment to achieve specified targets. In patients receiving a calcineurin inhibitor, Pravastatin should be commenced at a dose of 10 mg/day. In patients receiving other forms of immunosuppression, pravastatin may be commenced at a dose of 20 mg/day. Liver tests should be monitored and patients warned to report myalgia. If monotherapy is inadequate, ezetimibe or a fibrate may be added. Consideration may be given to change in immunosuppression if combination lipid-lowering therapy proves inadequate.

Cyclosporine nephrotoxicity

Cyclosporine (CsA) is the current primary immunosuppressant for the prevention of allograft rejection in solid organ transplantation. However, owing to its molecular mechanism of action the drug is associated with various adverse side effects (eg, nephrotoxicity). Histological changes appear as obliterative vasculopathy of the afferent arteriole and tubulointerstitial fibrosis in advanced cases. The underlying pathomechanisms of this condition reflect an altered release of vasoactive substances, such as angiotensin II, endothelin, prostaglandins, and nitric oxide as well as the stimulation of proliferative genes such as transforming growth factor-beta, osteopontin, and collagen I and IV. Potential strategies for the prevention of nephrotoxicity are discussed.

Drug-Induced Renal Failure in the ICU

Drug-induced renal failure is a frequent complication in the setting of ICU. Generally spoken pathomechanisms leading to drug-induced renal failure can be divided into hemodynamic effects, epithelial toxicity or crystalline nephropathy. The risk of drug-induced renal failure is increased by any form of hypovolemia (i.e. true hypovolemia or reduced effective circulating volume), older age, pre-existent renal impairment, and concomitant application of two or more nephrotoxins. This article reviews drugs most frequently responsible for renal failure in the ICU and discusses preventive measures. (Int J Artif Organs 2004; 27: 1034-42)

Calcium channel blockade and preservation of renal graft function in cyclosporine-treated recipients: a prospective randomized placebo-controlled 2-year study

BACKGROUND

Studies have provided conflicting results as to the protective role of calcium channel blockers (CCB) in cyclosporine-treated patients with regard to blood pressure control and preservation of renal graft function. Lacidipine is a dihydropyridine CCB that possesses antioxidative, anti-atherosclerotic, and anti-adhesion properties and was shown to prevent cyclosporine-induced nephrotoxicity in a rat model.

METHODS

We conducted a multicenter prospective, randomized, placebo-controlled study in 131 de novo recipients of a cadaveric renal allograft on cyclosporine therapy. The aim of this 2-year study was to assess the effects of lacidipine on graft function (plasma iohexol clearance), renal plasma flow, anastomotic arterial blood flow, deterioration of renal function, blood pressure, acute rejection, and hospitalization rate.

RESULTS

A total of 118 recipients were available for intention-to-treat analysis on efficacy (lacidipine: n=59; placebo: n=59). Graft function assessed by serum creatinine concentration and glomerular filtration rate measured as plasma iohexol clearance, was persistently better in lacidipine-treated patients from 1 year onwards (respectively, P<0.01 and P<0.05). Renal plasma flow and anastomotic blood flow were not significantly higher in lacidipine-treated patients. Three patients on lacidipine therapy and four on placebo experienced treatment failure defined as an increase in serum creatinine from baseline of more than 60% (log-rank test: P=0.57). Study groups did not differ in acute rejection rate, trough blood cyclosporine concentrations, blood pressure, number of antihypertensive drugs, hospitalization rate, and adverse event rate.

CONCLUSIONS

The use of calcium channel blockers in cyclosporine-treated renal recipients results in a significantly better allograft function at 2 years and this effect is independent of blood pressure lowering.

Diltiazem use in tacrolimus-treated renal transplant recipients

BACKGROUND

Calcium channel blockers are widely used in the treatment of post-transplant hypertension but have the potential for drug interaction with calcineurin inhibitors. Renal allograft outcomes when diltiazem is used with cyclosporine have been reported, but similar data with tacrolimus are not available.

METHODS

We performed a retrospective analysis of all our renal transplant recipients from March 1997 to March 2002 who were given tacrolimus, mycophenolate mofetil and prednisone. Patients were divided into two groups based on whether diltiazem was started in the first postoperative week. Outcome measures included renal function up to 2 years post-transplant, blood pressure (BP) control, tacrolimus exposure, and costs related to tacrolimus monitoring.

RESULTS

Sixty-four patients constituted the diltiazem group and 32 the control group. Their baseline characteristics were similar. The mean average daily dose of diltiazem used was 213.95 mg/day. There was no difference in renal function, graft survival, or patient survival over 2 years. BP control was similar although the diltiazem group required more medication. Diltiazem was discontinued in four patients due to side-effects. There was no difference in tacrolimus-related side-effects between the two groups. There was also no difference in tacrolimus exposure, cost related to tacrolimus monitoring, or combined costs when the expense of diltiazem was added.

CONCLUSION

Diltiazem use is acceptably safe and efficacious in renal transplant recipients treated with tacrolimus-based immunosuppressive therapy. It can be considered as a first-line antihypertensive in these patients and is cost neutral for tacrolimus use.

Drug Therapy in Transplant Recipients

Elderly patients with end-stage organ failure are now more frequently undergoing transplantation. Medication management in this population is challenging because of the combination of multiple comorbidities, polypharmacy, and immunological, pharmacokinetic and pharmacodynamic changes attributable to the aging process. Immunosuppressive medications can exacerbate pre-existing medical conditions and promote the development of disease processes. Cardiovascular disorders, such as hypertension, coronary artery disease, congestive heart failure and arrhythmias are common in elderly transplant recipients, and account for most of the deaths in this population. Blood pressure, blood glucose and cholesterol control is of particular concern because elderly transplant recipients frequently have or develop these complications. Elderly transplant recipients are commonly receiving anticoagulation therapy with warfarin and are at a higher risk of bleeding, especially if they have renal dysfunction. Infectious complications occur frequently in the transplanted population, with pneumonia being the most common infection seen in hospitalised patients. Attention to vaccination for the prevention of influenza and pneumococcal infections is important because of the increased risk of these diseases in this population. Depression itself has been associated with decreased survival in older individuals, and depression in elderly transplant recipients may be reversible with the administration of pharmacological agents. Effective long-term care of transplant recipients demands an understanding of how particular medications affect clinical evaluation and treatment. This article addresses some of the practical issues surrounding medication management and prevention of these particular problems in elderly transplant recipients.

Use of calcium antagonists in renal patients: therapeutic benefit or medical malpractice?

In patients with kidney disease, control of hypertension is paramount in helping to slow down the progression of both diabetic and nondiabetic nephropathy. A significant amount of data have been published that suggest blockade of the renin-angiotensin system should be considered as first-line therapy for patients with kidney disease. Meanwhile, some studies have suggested that the use of calcium channel blockers may have deleterious effects on patients with kidney disease. This manuscript reviews the renal outcomes of trials in which calcium channel blockers were included in the management of patients with and without kidney disease. The data suggest that agents that block the renin-angiotensin system are superior to calcium channel blockers in protecting against progressive kidney disease. However, there is no conclusive evidence that calcium channel blockers are injurious to the kidney, and they may be particularly beneficial in post-renal transplant patients.

Hypertension increases expression of growth factors and MHC II in chronic allograft nephropathy

BACKGROUND

Hypertension of the recipient is strongly associated with chronic allograft nephropathy. It is unclear, however, whether hypertension is the cause or the consequence of chronic allograft nephropathy.

METHODS

The present study was performed in the Fisher to Lewis rat kidney transplant model. Transplanted rats (N = eight in each group) received either no treatment or were made hypertensive by administration of deoxycorticosteron acetate (DOCA) and salt. Proteinuria and systolic blood pressure was measured monthly, grafts were harvested at 3 and 6 months for semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and for immunohistology.

RESULTS

Systolic blood pressure was markedly elevated in rats receiving DOCA/salt. Allografts of hypertensive animals contained significantly more cells expressing the proliferating cell nuclear antigen compared to isografts and to allografts from normotensive animals (P < 0.05). Histologic staining and mRNA expression of major histocompatibility complex (MHC) II was markedly increased in allografts of hypertensive animals compared to all other groups (P < 0.05). Expression of mRNA for platelet-derived growth factor-B (PDGF-B), transforming growth factor-beta (TGF-beta) and collagen was higher in allografts than in isografts and was highest in hypertensive animals.

CONCLUSION

We conclude that hypertension augments the expression of growth factors in the allograft possibly aggravating the intimal hyperplasia observed in chronic allograft nephropathy. By increasing the expression of MHC II antigens, hypertension may render the allograft more susceptible to alloantigen-dependent damage. Hypertension and alloantigen-dependent factors appear to exert additive or synergistic effects on inflammatory pathways leading to graft injury.

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.

Acute renal failure in hospitalized patients: part II

BACKGROUND

Acute renal failure (ARF) is a common condition in hospitalized patients. Research has been unable to identify the optimal target for therapeutic intervention; hence, effective prevention of and/or treatment for ARF remain elusive.

OBJECTIVE

To examine the usefulness of current and potential pharmacologic treatments in seriously ill, hospitalized patients.

DATA SOURCES

A MEDLINE search (1996-June 2002) was conducted using the search terms kidney (drug effects) and acute kidney failure (drug therapy). Bibliographies of selected articles were also examined to include all relevant investigations.

STUDY SELECTION AND DATA EXTRACTION

Review articles, meta-analyses, and clinical trials describing prevention of and treatment for hospital-acquired ARF were identified. Results from prospective, controlled trials were given priority when available.

CONCLUSIONS

Appropriate management of ARF includes prospective identification of at-risk patients, fluid administration, and optimal hemodynamic support. Drug treatments, including low-dose dopamine and diuretics, have demonstrated extremely limited benefits and have not been shown to improve patient outcome. Experimental agents influence cellular processes of renal dysfunction and recovery; unfortunately, relatively few drugs show promise for the future.

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.

Sustained improvement of renal graft function for two years in hypertensive renal transplant recipients treated with nifedipine as compared to lisinopril

BACKGROUND

Treatment of posttransplant hypertension is still a matter of debate. Calcium antagonists may ameliorate renal side effects of cyclosporin. Angiotensin converting enzyme- (ACE) inhibitors may be more effective in sustaining renal function in native chronic renal disease. We prospectively compared the effect of controlled release nifedipine and lisinopril on long-term renal function in hypertensive kidney transplant patients treated with cyclosporin.

METHODS

A total of 154 renal transplant patients presenting with hypertension (diastolic blood pressure >or=95 mmHg) during the first 3 weeks after transplantation were randomised to receive double-blind nifedipine 30 mg or lisinopril 10 mg once daily. A total of 123 patients completed 1 year of treatment (69 nifedipine, 54 lisinopril) and 64 patients completed 2 years of double-blind treatment (39 nifedipine, 25 lisinopril). Baseline glomerular filtration rate was measured as 99 mTc-diethylene-triaminepentaacetate clearance in a stable phase 2 to 5 weeks after inclusion and repeated at 1 and 2 years.

RESULTS

Baseline glomerular filtration rates were similar (46+/-16 ml/min with nifedipine, 43+/-14 ml/min with lisinopril). The changes in glomerular filtration rates from baseline were statistically significant between the groups after 1 year (9.6 ml/min mean treatment difference (95% confidence interval [CI]s 5.5-13.7 ml/min, P=0.0001) and remained statistically significant also after 2 years (10.3 ml/min mean difference (95% CIs 4.0-16.6], P=0.0017). After 1 year glomerular filtration rates averaged 56+/-19 ml/min in the nifedipine group and 44+/-14 ml/min in the lisinopril group.

CONCLUSIONS

Both nifedipine and lisinopril were safe and effective in treatment of hypertension in renal transplant patients treated with cyclosporin. Patients receiving nifedipine but not lisinopril improved kidney transplant function over a period of 2 years.

Efficacy of nifedipine or lisinopril in the treatment of hypertension after renal transplantation: a double-blind randomised comparative trial

Calcium channel blockers and angiotensin converting enzyme-inhibitors are commonly used in the treatment of hypertensive renal transplant recipients. The purpose of this study was to investigate if the response rate to treatment differs with these drugs in this setting. A single centre, prospective, randomised, double-blinded, comparative study to address the efficacy of controlled release nifedipine or lisinopril in the treatment of hypertension (diastolic blood pressure > or =95 mmHg) in cyclosporin (CsA)-treated renal transplant recipients was performed. Recipients were randomised to receive either lisinopril (10 mg once daily) or controlled release nifedipine (30 mg once daily). The dose was doubled on indication. The number of responders (diastolic blood pressure <90 mmHg on monotherapy) were addressed during the early post-transplant phase (first 3 months) and during a late post-transplant phase (from 3 to 12 months after renal transplantation) in the same patient population. One hundred and fifty-four patients (nifedipine=78, lisinopril=76) with untreated hypertension (diastolic blood pressure> or =95 mmHg) were randomised within 3 wk after renal transplantation. One hundred and twenty-three patients (nifedipine=69, lisinopril=54) completed the study. Fourteen (20%) nifedipine-treated recipients responded during the early, and 26 (38%) during the late post-operative phase (months 4-12 after renal transplantation). Eleven (20%) lisinopril-treated recipients responded during the early, and 18 (33%) during the late post-transplant phase. Non-responders were, on average, 8.5+/-1.5 kg heavier both in the early phase and after 1 yr of treatment (p<0.01), and 6.1+/-0.9 yr older than responders (p<0.05). In conclusion, these results indicate that both controlled release nifedipine and lisinopril are equally efficient in the treatment of post-transplant hypertension. As monotherapy, both drugs show a "response rate" of 20-38%, depending on time interval after transplantation.

Follow-up of renal function in treated and untreated older patients with isolated systolic hypertension. Systolic Hypertension in Europe (Syst-Eur) Trial Investigators

BACKGROUND

In the outcome trials that provided information on renal function in older hypertensive patients, diuretics and beta-blockers were mostly used as first-line drugs. The long-term renal effects of calcium-channel blockers remain unclear.

OBJECTIVE

To compare the changes in renal function in 2,258 treated and 2,148 untreated patients with isolated systolic hypertension, of whom 455 had diabetes mellitus and 390 had proteinuria.

METHODS

We performed a post-hoc analysis of the double-blind placebo-controlled Systolic Hypertension in Europe (Syst-Eur) Trial. Active treatment was initiated with nitrendipine (10-40 mg/day) with the possible addition of enalapril (5-20 mg/day), hydrochlorothiazide (12.5-25 mg/day), or both, titrated or combined to reduce the sitting systolic blood pressure by at least 20 mmHg, to less than 150 mmHg. The main outcome measures were serum creatinine concentration and creatinine clearance calculated by the formula of Cockroft and Gault.

RESULTS

Serum creatinine concentration at the time when participants were randomly allocated to study groups was less than 176.8 micromol/l (2.0 mg/dl), averaging 88 micromol/l. At the time of the last serum creatinine measurement, the blood pressure difference (P< 0.001) between the two groups was 11.6/4.1 mmHg. In the intention-to-treat analysis (11,427 patient-years), serum creatinine and the calculated creatinine clearance were not influenced by active treatment. However, in the patients assigned randomly to receive active treatment, the incidence of mild renal dysfunction (serum creatinine at least 176.8 mmol/l) decreased by 64% (P= 0.04) and that of proteinuria by 33% (P= 0.03). Active treatment reduced the risk of proteinuria more in diabetic than in non-diabetic patients: by 71%, compared with 20% (P= 0.04). In non-proteinuric patients, active treatment did not influence serum creatinine, whereas in patients with proteinuria at entry to the study, serum creatinine decreased on active treatment (P< 0.001). Furthermore, in on-randomized treatment comparison stratified for risk at baseline, serum creatinine concentration did not change (P= 0.98) in patients continuing to receive monotherapy with nitrendipine, whereas it increased by 6.73 mmol/l (P < 0.001) in patients who received hydrochlorothiazide alone or in combination with other study medication (P < 0.001 for difference in trends).

CONCLUSIONS

In older patients with isolated systolic hypertension, antihypertensive treatment starting with the dihydropyridine calcium-channel blocker, nitrendipine, did not decrease blood pressure at the expense of renal function and prevented the development of proteinuria, especially in diabetic patients.

Renal toxicity associated with disease-modifying antirheumatic drugs used for the treatment of rheumatoid arthritis

OBJECTIVE

To provide a review of the renal toxicity of disease-modifying antirheumatic drugs (DMARDs) currently used for the treatment of rheumatoid arthritis.

METHODS

Papers in American and European medical journals related to renal toxicity of DMARDs used for the treatment of rheumatoid arthritis were reviewed. Specific DMARDs reviewed were cyclosporine, gold, D-penicillamine, methotrexate, azathioprine, antimalarials, sulfasalazine, leflunomide, etanercept, infliximab, and DMARD combination therapy.

RESULTS

The renal toxicity of DMARDs varies widely. Cyclosporine, gold, and D-penicillamine all have a serious potential for renal side effects, particularly in the elderly or in patients with compromised renal function. Concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs) increases the potential for renal damage. In contrast, methotrexate, azathioprine, antimalarials, sulfasalazine, leflunomide, etanercept, and infliximab have relatively little renal toxicity.

CONCLUSIONS

The potential for renal toxicity should always be considered when determining which DMARD to use for RA therapy. DMARDs that combine efficacy with negligible renal adverse effects should be used for the treatment of patients susceptible to DMARD-associated renal damage.

Are calcium antagonists effective in preventing complications of hypertension and progression of renal disease?

Long-acting calcium antagonists have been shown to be safe and effective in lowering blood pressure, both as first-line agents and in combination with other classes of antihypertensive drug. They have also been shown to reduce the incidence of cerebrovascular and cardiovascular events in elderly patients with predominantly systolic hypertension. It is clear that reduced morbidity and mortality in hypertension is related to the degree to which blood pressure is reduced, regardless of the therapy used. This is the single most important conclusion of all recent trials, especially in the sub-group of hypertensive patients with diabetes. The World Health Organization-International Society of Hypertension guidelines acknowledge this and do not make specific recommendations as to initial therapy in the absence of other medical factors. However the use of thiazide diuretics and beta-blockers has strong support from large placebo-controlled trials in patients with mild-moderate essential hypertension. The British Hypertension Society and JNC VI guidelines restrict their recommendations for the use of calcium antagonists to isolated systolic hypertension and angina, or when other agents have failed, are contraindicated or are not tolerated. However, their efficacy in lowering blood pressure, their tolerability and potentially beneficial secondary effect on proteinuria, especially in combination with an angiotensin-converting enzyme inhibitor, still make them attractive antihypertensive agents. The results of further long-term outcome trials that make direct comparisons between calcium antagonists and other classes of antihypertensive drug are still awaited. Unlike angiotensin-converting enzyme inhibitors, the antiproteinuric effect of calcium antagonists, even that of the non-dihydropyridine type, seems to depend on an adequate and stable reduction in blood pressure.

Dihydropyridine calcium antagonists and renal function in hypertensive kidney transplant recipients

OBJECTIVE

To investigate whether calcium antagonists are nephroprotective in hypertensive cyclosporine-treated renal allograft recipients.

METHODS

We studied 50 hypertensive and 17 normotensive renal transplants (eight females, nine males; 14-54 years, mean age 38.8 +/- 3.5 years). Hypertensive patients were randomized to be treated with (+Ca; 11 females, 13 males; 20-65 years, mean age 43.1 +/- 3 years) or without (-Ca; 15 females, 11 males; 25-60 years, mean age 41.3 +/- 2.5 years) a calcium antagonist (nitrendipine or nifedipine). Additional antihypertensives were given stepwise according to a standardized protocol: beta1-adrenoceptor blocker, diuretic alpha1-adrenoceptor blocker or vasodilator. Data were analysed at 0, 1, 2 and 3 years on an intention-to-treat basis.

RESULTS

Hypertensive patients had a higher body mass index at 0/3 years (23.7 +/- 0.6/25.1 +/- 0.6 kg/m2) than normotensive patients (22.2 +/- 0.6/22.1 +/- 0.7 kg/m2). During the study, blood pressure in normotensive transplants was always slightly, but not significantly, lower than that of transplants with treated hypertension. There was no difference between the groups (+Ca) and (-Ca). Cr51-ethylenediaminetetracetic acid (EDTA) clearance (0/2 years) was 58 +/- 4/57 +/- 6 ml/min in normotensives, 52 +/- 4/47 +/- 4 ml/min in hypertensives (+Ca) and 47 +/- 4/49 +/- 6 ml/min in hypertensives (-Ca). Proteinuria (0/3 years) was 0.16 +/- 0.04/0.15 +/- 0.02 g/24 h in normotensive, 0.26 +/- 0.08/0.23 +/- 0.05 g/24 h in hypertensives (+Ca) and 0.26 +/- 0.07/0.22 +/- 0.05 g/24 h in hypertensives (-Ca).

CONCLUSIONS

Post-transplant hypertension is associated with higher body mass index and poor renal function. No difference in the course of Cr51-EDTA clearance, serum creatinine, proteinuria or blood pressure was observed between groups treated with or without calcium antagonists. Calcium antagonists and conventional antihypertensive treatment have the same nephroprotective effect in hypertensive renal transplants, when treatment is started 3 months after transplantation.