Mechanism of cyclosporine-induced hypertension

Risk of Developing Hypertension in Atopic Dermatitis Patients Receiving Long-term and Low-dose Cyclosporine: A Nationwide Population-based Cohort Study

BACKGROUND

Cyclosporine (CS) is a first-line immunosuppressive agent used to manage moderate to severe atopic dermatitis (AD). To date, the risk of developing hypertension associated with the long-term use of low-dose CS in AD patients is understudied.

OBJECTIVE

To determine the cumulative dose-dependent effect of CS on the risk of developing hypertension in patients with AD.

METHODS

A nationwide population-based retrospective cohort with 1,844,009 AD patients was built from the Korean National Health Insurance System database from 2005 to 2009. A Cox proportional-hazard regression analysis was performed according to patients' CS treatment history adjusted for potential confounders.

RESULTS

Current use of CS was associated with an increased risk of developing hypertension (adjusted hazard ratio, 4.442; 95% confidence interval, 3.761-5.247). Among the current CS users, a higher cumulative dose of CS (≥39,725 mg) or longer cumulative use of CS (≥182 days), was significantly associated with an increased risk of developing hypertension.

CONCLUSION

The incidence of CS-associated hypertension is very low when using low-dose treatment regimens for AD. However, the current use or a high cumulative dose of CS for treating patients with AD increases the risk of developing hypertension. Precaution is needed when prescribing CS for long-term treatment of AD.

Calcineurin Is a Universal Regulator of Vessel Function-Focus on Vascular Smooth Muscle Cells

Calcineurin, a serine/threonine phosphatase regulating transcription factors like NFaT and CREB, is well known for its immune modulatory effects and role in cardiac hypertrophy. Results from experiments with calcineurin knockout animals and calcineurin inhibitors indicate that calcineurin also plays a crucial role in vascular function, especially in vascular smooth muscle cells (VSMCs). In the aorta, calcineurin stimulates the proliferation and migration of VSMCs in response to vascular injury or angiotensin II administration, leading to pathological vessel wall thickening. In the heart, calcineurin mediates coronary artery formation and VSMC differentiation, which are crucial for proper heart development. In pulmonary VSMCs, calcineurin/NFaT signaling regulates the release of Ca2+, resulting in increased vascular tone followed by pulmonary arterial hypertension. In renal VSMCs, calcineurin regulates extracellular matrix secretion promoting fibrosis development. In the mesenteric and cerebral arteries, calcineurin mediates a phenotypic switch of VSMCs leading to altered cell function. Gaining deeper insights into the underlying mechanisms of calcineurin signaling will help researchers to understand developmental and pathogenetical aspects of the vasculature. In this review, we provide an overview of the physiological function and pathophysiology of calcineurin in the vascular system with a focus on vascular smooth muscle cells in different organs. Overall, there are indications that under certain pathological settings reduced calcineurin activity seems to be beneficial for cardiovascular health.

Emerging strategies to bypass transplant rejection via biomaterial-assisted immunoengineering: Insights from islets and beyond

Novel transplantation techniques are currently under development to preserve the function of impaired tissues or organs. While current technologies can enhance the survival of recipients, they have remained elusive to date due to graft rejection by undesired in vivo immune responses despite systemic prescription of immunosuppressants. The need for life-long immunomodulation and serious adverse effects of current medicines, the development of novel biomaterial-based immunoengineering strategies has attracted much attention lately. Immunomodulatory 3D platforms can alter immune responses locally and/or prevent transplant rejection through the protection of the graft from the attack of immune system. These new approaches aim to overcome the complexity of the long-term administration of systemic immunosuppressants, including the risks of infection, cancer incidence, and systemic toxicity. In addition, they can decrease the effective dose of the delivered drugs via direct delivery at the transplantation site. In this review, we comprehensively address the immune rejection mechanisms, followed by recent developments in biomaterial-based immunoengineering strategies to prolong transplant survival. We also compare the efficacy and safety of these new platforms with conventional agents. Finally, challenges and barriers for the clinical translation of the biomaterial-based immunoengineering transplants and prospects are discussed.

Role of hypertension in kidney transplant recipients

Cardiovascular events are one of the leading causes of mortality in kidney transplant recipients. Hypertension is the most common comorbidity accompanying chronic kidney disease, with prevalence remaining as high as 90% even after kidney transplantation. It is often poorly controlled. Abnormal blood pressure profiles, such as masked or white-coat hypertension, are also extremely common in these patients. The pathophysiology of blood pressure elevation in kidney transplant recipients is complex and includes transplantation-specific risk factors, which are added to the traditional or chronic kidney disease-related factors. Despite these observations, hypertension management has been an under-researched area in kidney transplantation. Thus, relevant evidence derives either from studies in the general population or from small trials in kidney transplant recipients. Based on the relevant guidelines in the general population, lifestyle modifications should probably be applied as the first step of hypertension management in kidney transplant recipients. The optimal pharmacological management of hypertension in kidney transplant recipients is also not clear. Dihydropyridine calcium channel blockers are commonly used as first line agents because of their lack of adverse effects on the kidney, while other antihypertensive drug classes are under-utilised due to fear of the possible haemodynamic consequences on renal function. This review summarizes the existing data on the pathophysiology, diagnosis, prognostic significance and management of hypertension in kidney transplantation.

Cyclosporin A: A Repurposable Drug in the Treatment of COVID-19?

Coronavirus disease 2019 (COVID-19) is now at the forefront of major health challenge faced globally, creating an urgent need for safe and efficient therapeutic strategies. Given the high attrition rates, high costs, and quite slow development of drug discovery, repurposing of known FDA-approved molecules is increasingly becoming an attractive issue in order to quickly find molecules capable of preventing and/or curing COVID-19 patients. Cyclosporin A (CsA), a common anti-rejection drug widely used in transplantation, has recently been shown to exhibit substantial anti-SARS-CoV-2 antiviral activity and anti-COVID-19 effect. Here, we review the molecular mechanisms of action of CsA in order to highlight why this molecule seems to be an interesting candidate for the therapeutic management of COVID-19 patients. We conclude that CsA could have at least three major targets in COVID-19 patients: (i) an anti-inflammatory effect reducing the production of proinflammatory cytokines, (ii) an antiviral effect preventing the formation of the viral RNA synthesis complex, and (iii) an effect on tissue damage and thrombosis by acting against the deleterious action of angiotensin II. Several preliminary CsA clinical trials performed on COVID-19 patients report lower incidence of death and suggest that this strategy should be investigated further in order to assess in which context the benefit/risk ratio of repurposing CsA as first-line therapy in COVID-19 is the most favorable.

Repurposing Immunomodulatory Therapies against Coronavirus Disease 2019 (COVID-19) in the Era of Cardiac Vigilance: A Systematic Review

The ongoing coronavirus disease 2019 (COVID-19) pandemic has resulted in efforts to identify therapies to ameliorate adverse clinical outcomes. The recognition of the key role for increased inflammation in COVID-19 has led to a proliferation of clinical trials targeting inflammation. The purpose of this review is to characterize the current state of immunotherapy trials in COVID-19, and focuses on associated cardiotoxicities, given the importance of pharmacovigilance. The search terms related to COVID-19 were queried in ClinicalTrials.gov. A total of 1621 trials were identified and screened for interventional trials directed at inflammation. Trials (n = 226) were fully assessed for the use of a repurposed drug, identifying a total of 141 therapeutic trials using a repurposed drug to target inflammation in COVID-19 infection. Building on the results of the Randomized Evaluation of COVID-19 Therapy (RECOVERY) trial demonstrating the benefit of low dose dexamethasone in COVID-19, repurposed drugs targeting inflammation are promising. Repurposed drugs directed at inflammation in COVID-19 primarily have been drawn from cancer therapies and immunomodulatory therapies, specifically targeted anti-inflammatory, anti-complement, and anti-rejection agents. The proposed mechanisms for many cytokine-directed and anti-rejection drugs are focused on evidence of efficacy in cytokine release syndromes in humans or animal models. Anti-complement-based therapies have the potential to decrease both inflammation and microvascular thrombosis. Cancer therapies are hypothesized to decrease vascular permeability and inflammation. Few publications to date describe using these drugs in COVID-19. Early COVID-19 intervention trials have re-emphasized the subtle, but important cardiotoxic sequelae of potential therapies on outcomes. The volume of trials targeting the COVID-19 hyper-inflammatory phase continues to grow rapidly with the evaluation of repurposed drugs and late-stage investigational agents. Leveraging known clinical safety profiles and pharmacodynamics allows swift investigation in clinical trials for a novel indication. Physicians should remain vigilant for cardiotoxicity, often not fully appreciated in small trials or in short time frames.

Current status of costimulatory blockade in renal transplantation

PURPOSE OF REVIEW

The review will focus on the impact and current status of costimulatory blockade in renal transplantation.

RECENT FINDINGS

The mainstay of immunosuppression in kidney transplantation is calcineurin inhibitors (CNIs) which have reduced acute rejection rates but failed to improve long-term allograft survival. Their cardiometabolic side-effects and nephrotoxicity have shifted the focus of investigation to CNI-free regimens. Costimulation blockade with belatacept, a second generation, higher avidity variant of cytotoxic T-lymphocyte associated protein 4 has emerged as part of a CNI-free regimen. Belatacept has demonstrated superior glomerular filtration rate compared with CNIs, albeit with an increased risk of early and histologically severe rejection. Focus on optimizing the belatacept regimen is underway. ASKP1240, which blocks the cluster of differentiation 40 (CD40)/CD154 costimulatory pathway, has just completed a phase 2 trial with a CNI-free regimen. CFZ533, an anti-CD40, is also poised to be tested in a phase 2 trial in renal transplantation. Nonagonistic CD28 antibodies have re-emerged with two anti-CD28 candidates in preclinical development.

SUMMARY

A reliable, CNI-free regimen that maintains low acute rejection rates and improves long-term renal allograft survival has become an achievable goal with costimulation blockade. The task of clinicians and researchers is to find the optimal combinations to maintain safety and improve efficacy.

Systemic immunosuppression in limbal stem cell transplantation: best practices and future challenges

The objective of this study was to evaluate systemic immunosuppression regimens used for patients undergoing ocular surface stem cell transplantation, including their benefits and adverse effects in the adjunctive management of limbal stem cell deficiency (LSCD). A systematic literature review was conducted using the MEDLINE and EMBASE databases (1980-2015). Data were collected on surgical intervention(s), type of immunosuppressive agent(s), duration of immunosuppression, percentage with stable ocular surface at last follow-up, mean follow-up time, and demographics. Data were also collected on adverse ocular and systemic outcomes. Sixteen reports met the inclusion criteria. There were no randomized controlled studies. Three studies were noncomparative prospective case series, whereas the majority were retrospective case series. Bilateral severe LSCD was the most common disease (50%), and keratolimbal allograft was the most common intervention (80%). Immunosuppressive regimens showed a progression from early studies using oral cyclosporine to later studies using combinations of mycophenolate mofetil and tacrolimus. Most studies included a course of high-dose systemic corticosteroids. For patients adherent to long-term systemic immunosuppression, stable ocular surface rates of 70%-80% at last follow-up were reported. Adverse effects included hypertension, diabetes mellitus, and biochemical abnormalities managed with pharmacotherapy or discontinuation of offending agents. There were no cases of mortality related to immunosuppression. However, the current literature does not elucidate which immunosuppressive regimen is most efficacious for different categories of LSCD or graft types. Evidence-based guidelines for systemic immunosuppression in limbal allograft therapy would benefit from randomized controlled and/or additional prospective studies. Long-term immunosuppression would benefit from close collaboration between ophthalmologists and transplant specialists to individualize treatments.

Myeloid-Derived Suppressor Cells Ameliorate Cyclosporine A-Induced Hypertension in Mice

The calcineurin inhibitor cyclosporine A (CsA) suppresses the immune system but promotes hypertension, vascular dysfunction, and renal damage. CsA decreases regulatory T cells and this contributes to the development of hypertension. However, CsA's effects on another important regulatory immune cell subset, myeloid-derived suppressor cells (MDSCs), is unknown. We hypothesized that augmenting MDSCs would ameliorate the CsA-induced hypertension and vascular and renal injury and dysfunction and that CsA reduces MDSCs in mice. Daily interleukin-33 treatment, which increased MDSC levels, completely prevented CsA-induced hypertension and vascular and renal toxicity. Adoptive transfer of MDSCs from control mice into CsA-treated mice after hypertension was established dose-dependently reduced blood pressure and vascular and glomerular injury. CsA treatment of aortas and kidneys isolated from control mice for 24 hours decreased relaxation responses and increased inflammation, respectively, and these effects were prevented by the presence of MDSCs. MDSCs also prevented the CsA-induced increase in fibronectin in microvascular and glomerular endothelial cells. Last, CsA dose-dependently reduced the number of MDSCs by inhibiting calcineurin and preventing cell proliferation, as other direct calcineurin signaling pathway inhibitors had the same dose-dependent effect. These data suggest that augmenting MDSCs can reduce the cardiovascular and renal toxicity and hypertension caused by CsA.

A single-centre, open-label, prospective study of an initially short-term intensified dosing regimen of enteric-coated mycophenolate sodium with reduced cyclosporine A exposure in Chinese live-donor kidney transplant recipients

AIMS

The nephrotoxicity of cyclosporine A (CsA) accounts for dysfunction of kidney allografts in the clinic. Short-term intensified dosing using enteric-coated mycophenolate sodium (EC-MPS) may facilitate CsA sparing after kidney transplantation without compromising safety.

METHODS

In a 12-month, single-centre open-label prospective trial, 180 de novo live-donor kidney transplant recipients at low-immunological risk were randomised to a low-dose cyclosporine group which received a low dose of cyclosporine, short-term intensified EC-MPS dosing (2160 mg/day to week 6, 1440 mg/day thereafter) and corticosteroids or a standard-dose cyclosporine group which received a standard dose of cyclosporine, standard EC-MPS dosing (1440 mg/day) and corticosteroids. The primary end-point [treatment failure including biopsy-proven acute rejection (BPAR), graft loss, death], secondary end-point and adverse events were monitored.

RESULTS

The primary end-point (treatment failure) occurred in 13.3% (12/90) of the low-dose cyclosporine group and 16.7% (15/90) of the standard-dose cyclosporine group (p = 0.53) (difference -3.4%, 95% confidence interval -11.7% to 7.5%, based on a noninferiority margin of 20%). BPAR occurred in 11.1% and 13.3% of patients in the low-dose cyclosporine group and standard-dose cyclosporine group, respectively (p = 0.65). The estimated glomerular filtration rate, as calculated by the Cockcroft-Gault formula, was similar at 12 months after transplantation (low-dose cyclosporine group 63 ± 19 ml/min/1.73 m(2) and standard-dose cyclosporine group 59 ± 15 ml/min/1.73 m(2) ; p = 0.43). The levels of serum creatinine and occurrence of adverse events between the two groups were not statistically different.

CONCLUSIONS

A regimen of early intensified EC-MPS dosing permits low-dose cyclosporine in live-donor kidney transplant patients at low-immunological risk without compromising efficacy at 12 months' follow-up.

Arterial hypertension in liver transplant recipients

Hypertension is an important cardiovascular risk factor that influences patient survival. This study sought to evaluate hypertension incidence and circadian rhythms of blood pressure (BP) among liver transplant recipients during the first posttransplant month. We also compared hypertension incidence according to clinical and automated blood pressure monitoring methods. BP was determined by clinical blood pressure monitoring (CBPM) methods and by automated blood pressure monitoring (ABPM) using the SpaceLabs device. We also assessed blood biochemistry, particularly kidney function parameters and immunosuppressive drug blood trough levels, among 32 white subjects (10 women and 22 men) of average age 47.58±14.19 years. The leading cause for transplantation was liver insufficiency due to viral hepatitis B and/or C infection (43.75%). The majority (93.75%) of patients was prescribed immunosuppressive treatment with tacrolimus. Although we observed hypertension in 28 patients (87.5%) by ABPM measurements and in 25 (78.12%) using CBPM method, the difference did not reach statistical significance. However, BP control was inadequate in 28 patients (87.5%) by ABPM assessment versus 3 (9.38%) according to CBPM readings (P=.025). The BP circadian rhythm was altered in 30 patients (93.75%) including 15 with higher nighttime BP readings. There was no correlation between tacrolimus blood levels and BP values or with kidney function as assessed by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. We concluded that prevalence of arterial hypertension among liver transplant recipients within 1 month after transplantation is high. The majority of the patients show disturbed circadian rhythms in the early period after liver transplantation with loss or even reversal of the normal nocturnal decrease in BP. Owing to the fact that ABPM enables more adequate daily assessment of BP values, it is an optimal method to adjust antihypertensive therapy to optimal levels.

Association between CYP3A5 polymorphisms and blood pressure in kidney transplant recipients receiving calcineurin inhibitors

Abstract Renal cytochrome P450 3A5 (CYP3A5) has been associated with blood pressure (BP) control in humans. We investigated whether CYP3A5 polymorphisms are associated with post- transplant hypertension in a selected population of kidney recipients receiving calcineurin inhibitors. Ninety-two kidney transplant recipients receiving cyclosporine (CyA) or tacrolimus (Tac) were genotyped for CYP3A5 polymorphisms, and the association between the CYP3A5 alleles (*1,*3) and hypertension on post-operative day (POD) 6 and POD 180 was verified, with multiple regression being used to identify the putative co-variates that may predict the extent and severity of hypertension in transplant recipients at different post-transplant times. The CYP3A5*1 carriers had higher systolic (SBP) and diastolic blood pressure (DBP) in both the immediate and delayed post-transplant period when adjusted for anti-hypertensive medication (POD 6: SBP = 161 ± 23 vs. 140 ± 23 mmHg; DBP = 120 ± 15 vs. 87 ± 14 mmHg, p < 0.05. POD 180: SBP = 136 ± 16 vs. 129 ± 14 mmHg; DBP = 89 ± 15 vs. 80 ± 15 mmHg, p < 0.05). The severity of hypertension between the CYP3A5*1 carriers and noncarriers on POD 6 was documented by the significantly different distribution of hypertension classes, but this was not confirmed on POD 180. The CYP3A5 genotype was the only independent variable affecting mean arterial pressure. The results of this study show that CYP3A5 polymorphisms are associated with the severity and degree of hypertension in kidney transplant recipients receiving calcineurin inhibitors regardless of the time of recording. However, the role of concomitant medications such as steroids with strong CYP3A5 inducing activity, should be taken into account.

Novel strategies in immunosuppression: issues in perspective

Recent findings suggest that a chronic alloimmune response is playing the dominant role in late allograft loss, challenging the notion that most grafts are lost due to the inexorable progression of calcineurin inhibitor (CNI) nephrotoxicity. CNIs have failed to improve long-term outcomes and are associated with multiple metabolic derangements. Thus, improvement in long-term allograft outcomes may depend on new agents with novel mechanisms of action, devoid of the toxicities associated with CNIs. To meet this need, inhibitors of novel pathways in B cell and plasma cell activation have emerged to combat the humoral immune response including belimumab and atacicept, both promising targets of B-cell survival factors and bortezomib and eculizumab, agents currently in trials for desensitization protocols and treatment of antibody-mediated rejection. Promising agents for maintenance immunosuppression, used as monotherapy or synergistically, include monoclonal antibodies and fusion receptor proteins targeting the CD40-CD154 pathway (multiple anti-CD40 antibodies), the CD28-CD80/86 pathway (i.e., belatacept), the LFA3-CD2 pathway (i.e., alefacept), and small molecules such as tofacitinib, a janus kinase 1/3 inhibitor. The induction of allograft tolerance has been attempted with some success with simultaneous bone marrow/kidney transplantation from the same donor, albeit, limited by its associated toxicites. Finally, the exciting fields of tissue engineering and stem cell biology with the repopulation of decellularized organs is ushering in a new paradigm for transplantation. The era of simplified immunosuppression regimens devoid of toxicities is upon us with the promise of dramatic improvement in long term survival.

HNF4alpha dysfunction as a molecular rational for cyclosporine induced hypertension

Induction of tolerance against grafted organs is achieved by the immunosuppressive agent cyclosporine, a prominent member of the calcineurin inhibitors. Unfortunately, its lifetime use is associated with hypertension and nephrotoxicity. Several mechanism for cyclosporine induced hypertension have been proposed, i.e. activation of the sympathetic nervous system, endothelin-mediated systemic vasoconstriction, impaired vasodilatation secondary to reduction in prostaglandin and nitric oxide, altered cytosolic calcium translocation, and activation of the renin-angiotensin system (RAS). In this regard the molecular basis for undue RAS activation and an increased signaling of the vasoactive oligopeptide angiotensin II (AngII) remain elusive. Notably, angiotensinogen (AGT) is the precursor of AngII and transcriptional regulation of AGT is controlled by the hepatic nuclear factor HNF4alpha. To better understand the molecular events associated with cyclosporine induced hypertension, we investigated the effect of cyclosporine on HNF4alpha expression and activity and searched for novel HNF4alpha target genes among members of the RAS cascade. Using bioinformatic algorithm and EMSA bandshift assays we identified angiotensin II receptor type 1 (AGTR1), angiotensin I converting enzyme (ACE), and angiotensin I converting enzyme 2 (ACE2) as genes targeted by HNF4alpha. Notably, cyclosporine represses HNF4alpha gene and protein expression and its DNA-binding activity at consensus sequences to AGT, AGTR1, ACE, and ACE2. Consequently, the gene expression of AGT, AGTR1, and ACE2 was significantly reduced as evidenced by quantitative real-time RT-PCR. While RAS is composed of a sophisticated interplay between multiple factors we propose a decrease of ACE2 to enforce AngII signaling via AGTR1 to ultimately result in vasoconstriction and hypertension. Taken collectively we demonstrate cyclosporine to repress HNF4alpha activity through calcineurin inhibitor mediated inhibition of nuclear factor of activation of T-cells (NFAT) which in turn represses HNF4alpha that leads to a disturbed balance of RAS.

The use of cyclosporine in dermatology: part II

Cyclosporine is highly effective in the treatment of a multitude of dermatoses. Concern over its side effect profile has limited its use in dermatology. Adverse effects are, for the most part, dose dependent and related to duration of therapy. Using the recommended monitoring protocols results in a significant decrease in the incidence of cyclosporine-related toxicities. This article provides a comprehensive review of the pharmacokinetics of cyclosporine, potential drug interactions, adverse effects, and recommendations for monitoring in patients treated with cyclosporine. The use of cyclosporine in pregnancy and in the pediatric population is also addressed.

LEARNING OBJECTIVES

After completing this learning activity, participants should be familiar with the monitoring guidelines of cyclosporine, its contraindications, its possible drug interactions, its adverse effect profile, and its use in pregnancy and the childhood and adolescent populations.

It takes time after bilateral nephrectomy for better control of resistant hypertension in renal transplant patients

Severe resistant hypertension in end-stage renal disease patients has traditionally been an indication for bilateral nephrectomy (BN) before kidney transplantation. Nevertheless the influence of BN on successful control of hypertension has not been well documented. We sought to clarify the effect of BN on blood pressure patterns and control in renal transplant patients.

MATERIALS AND METHODS

We retrospectively reviewed 28 patients who underwent BN between November 2003 and May 2009 before or after kidney transplantation. Nineteen of them were under treatment with 4 or 5 antihypertensives according to the international guide lines; they had BN for resistant hypertension. They were considered as group 1 (G1). Nine patients operated for indications other than resistant hypertension; they constitute group 2 (G2) and considered as a control group. All patients received triple immunosuppression according to our local protocol. BN was done either before, simultaneously or after transplantation. Antihypertensives were recorded before and after BN. We evaluated our patients at 3 months, 1 year, and 3 years. Acute rejection episodes and calcinurein nephrotoxicity were reported.

RESULTS

In G1, the mean age was 30.2 years (range, 10-62). In G2, the mean age was 33.6 years (range, 11-61). Before BN, G1 patients used antihypertensive drugs (3.6 +/- 1.05 drugs per day; mean +/- SD), which was significantly higher than in G2 patients (2.0 +/- 1.65 drugs per day; P = .02). Three months after BN, G1 patients used 2.6 + 0.9 drugs per day, with gradual reduction in number of antihypertensives to 1.4 +/- 1.3 drugs per day at 3 years (P = .008). In G2, there was reduction in antihypertensive drug number per day, which was insignificant during the follow-up period. No difference was noted between G1 and G2 drug administered after BN. We conclude that BN is effective to help blood pressure control, in resistant hypertension in renal transplant patients, but it starts to show up 3 months after surgery, and continues to work for a year and more.

Mycophenolic acid exposure after administration of mycophenolate mofetil in the presence and absence of cyclosporin in renal transplant recipients

BACKGROUND AND OBJECTIVE

The pharmacokinetics of mycophenolic acid (MPA) are complex, with large interindividual variability over time. There are also well documented interactions with cyclosporin, and assessment of MPA exposure is therefore necessary when reducing or stopping cyclosporin therapy. Here we report on the pharmacokinetic and pharmacodynamic behaviour of MPA in renal transplant patients on standard dose, reduced dose and no cyclosporin.

STUDY DESIGN

The CAESAR study, a prospective 12-month study in primary renal allograft recipients, was designed to determine whether mycophenolate mofetil-based regimens containing either low-dose cyclosporin or low-dose cyclosporin withdrawn by 6 months could minimize nephrotoxicity and improve renal function without an increase in acute rejection compared with a mycophenolate mofetil-based regimen containing standard-dose cyclosporin.

PATIENTS AND METHODS

A subset of patients from the CAESAR study contributed to this pharmacokinetic analysis of MPA exposure. Blood samples were taken over one dosing interval on day 7 and at months 3, 7 and 12 post-transplantation. The sampling time points were predose, 20, 40 and 75 minutes and 2, 3, 4, 6, 8 and 12 hours after mycophenolate mofetil dosing. Assessments included plasma concentrations of MPA and mycophenolic acid glucuronide (MPAG) and cyclosporin trough concentrations. The area under the plasma concentration-time curve (AUC) from 0 to 12 hours (AUC(12)) for MPA was the primary pharmacokinetic parameter, and the AUC(12) for MPAG was the secondary parameter.

RESULTS

In total, 536 de novo renal allograft recipients were randomized in the CAESAR study. Of these, 114 patients were entered into the pharmacokinetic substudy and 110 patients contributed to the pharmacokinetic analysis. There was a rapid rise in MPA concentrations (median time to peak concentration 0.72-1.25 hours). At day 7 and month 3, the MPA AUC(12) values were similar in the cyclosporin withdrawal and low-dose cyclosporin groups (patients with the same cyclosporin target concentrations to month 6), while at 7 and 12 months, the values in the cyclosporin withdrawal group were higher than in the low-dose group (19.9% and 30.2% higher, respectively). MPA AUC(12) values in the standard-dose cyclosporin group were lower than in the other groups at all time points and increased over time. At all time points, the MPA peak plasma concentration was similar in all groups, and the MPAG concentrations rose more slowly than MPA concentrations. The ratio of the AUC from 6 to 12 hours/AUC(12) suggests that an increasing AUC in the cyclosporin withdrawal group is due to an increase in the enterohepatic recirculation.

CONCLUSION

These findings are consistent with the hypothesis that cyclosporin inhibits the biliary secretion and/or hepatic extraction of MPAG, leading to a reduced rate of enterohepatic recirculation of MPA. Several concurrent mechanisms, such as cyclosporin-induced changes in renal tubular MPAG excretion and enhanced elimination of free MPA through competitive albumin binding with MPAG, can also contribute to the altered MPAG pharmacokinetics observed in the presence and absence of cyclosporin.

Posttransplant metabolic syndrome: an epidemic waiting to happen

With increasing survival after orthotopic liver transplantation (OLT), metabolic syndrome and its individual components, including diabetes mellitus, hypertension, dyslipidemia, and obesity, are increasingly being identified and contributing to cardiovascular complications and late morbidity and mortality. The prevalence of posttransplant metabolic syndrome (PTMS) and its individual components has been found to be higher post-OLT versus a comparable population without OLT. The development of nonalcoholic fatty liver disease (NAFLD) after liver transplantation for non-NAFLD cirrhosis is also being increasingly recognized. A number of predictors have been identified as potential risk factors related to these complications. The pretransplant risk factors include immunosuppression, a higher age at transplant, male gender, a history of smoking, the pretransplant body mass index, pre-OLT diabetes, the etiology of the underlying liver disease that resulted in OLT (hepatitis C, cryptogenic cirrhosis, or alcohol), an increased donor body mass index, and marital status. Although there is an increased risk of cardiovascular events, rejection, and infection among patients with PTMS, the overall impact on long-term survival and mortality remains inconclusive. Strategies to reduce the development of metabolic syndrome after transplantation should include lifestyle modifications involving alterations in diet and increased physical activity. Additional measures that may be potentially beneficial include the use of lipid-lowering agents, the optimal control of blood glucose, and the use of tacrolimus instead of cyclosporine.

The use of ciclosporin in psoriasis

Ciclosporin is a cyclic undecapeptide discovered in the 1970s to possess a potent inhibitory action on T lymphocytes. The subsequent discovery, in 1979, that it was remarkably effective in treatment of psoriasis transformed thinking about the nature of the disease, which subsequently became generally recognized as autoimmune in nature. Ciclosporin remains one of the most effective and rapidly acting treatments currently available for psoriasis. Virtually all the diverse manifestations of this disease can respond. The main side effects are nephrotoxicity and hypertension. There is considerable variation between individuals in susceptibility to these so careful monitoring is required. Ciclosporin should be used in single or intermittent short courses for all except the most severe cases as this is safer than continuous treatment. The rate of improvement depends very much on the dose, which ranges from 2 to 5.0 mg/kg/day. Ciclosporin can be combined with any topical treatment and a useful dose-sparing effect can be achieved in this way if patients are compliant. In severe cases ciclosporin is often used in combination with other systemic antipsoriatic drugs in order to spare the dose of each agent and reduce toxicity. Concurrent or intercurrent use of ultraviolet therapy is discouraged due to the increased risk of non-melanoma skin cancer. This article reviews the mode of action, pharmacokinetics, indications, contraindications, side effects, dosage regimens, pretreatment screening and monitoring, drug interactions, and use of treatment combinations with ciclosporin in the management of psoriasis.

Reduced exposure to calcineurin inhibitors in renal transplantation

BACKGROUND

Immunosuppressive regimens with the fewest possible toxic effects are desirable for transplant recipients. This study evaluated the efficacy and relative toxic effects of four immunosuppressive regimens.

METHODS

We randomly assigned 1645 renal-transplant recipients to receive standard-dose cyclosporine, mycophenolate mofetil, and corticosteroids, or daclizumab induction, mycophenolate mofetil, and corticosteroids in combination with low-dose cyclosporine, low-dose tacrolimus, or low-dose sirolimus. The primary end point was the estimated glomerular filtration rate (GFR), as calculated by the Cockcroft-Gault formula, 12 months after transplantation. Secondary end points included acute rejection and allograft survival.

RESULTS

The mean calculated GFR was higher in patients receiving low-dose tacrolimus (65.4 ml per minute) than in the other three groups (range, 56.7 to 59.4 ml per minute). The rate of biopsy-proven acute rejection was lower in patients receiving low-dose tacrolimus (12.3%) than in those receiving standard-dose cyclosporine (25.8%), low-dose cyclosporine (24.0%), or low-dose sirolimus (37.2%). Allograft survival differed significantly among the four groups (P=0.02) and was highest in the low-dose tacrolimus group (94.2%), followed by the low-dose cyclosporine group (93.1%), the standard-dose cyclosporine group (89.3%), and the low-dose sirolimus group (89.3%). Serious adverse events were more common in the low-dose sirolimus group than in the other groups (53.2% vs. a range of 43.4 to 44.3%), although a similar proportion of patients in each group had at least one adverse event during treatment (86.3 to 90.5%).

CONCLUSIONS

A regimen of daclizumab, mycophenolate mofetil, and corticosteroids in combination with low-dose tacrolimus may be advantageous for renal function, allograft survival, and acute rejection rates, as compared with regimens containing daclizumab induction plus either low-dose cyclosporine or low-dose sirolimus or with standard-dose cyclosporine without induction. (ClinicalTrials.gov number, NCT00231764 [ClinicalTrials.gov].).

Cyclosporine sparing with mycophenolate mofetil, daclizumab and corticosteroids in renal allograft recipients: the CAESAR Study

Although the calcineurin inhibitors (CNI) cyclosporine (CsA) and tacrolimus are highly effective immunosuppressants, they are associated with serious side effects. There is great interest in immunosuppressive regimens that permit reduction or elimination of CNIs, while maintaining adequate immunosuppression and acceptable acute rejection rates. Patients (n = 536) receiving their first renal allograft were randomized to one of three immunosuppressant regimens: daclizumab, mycophenolate mofetil (MMF), corticosteroids (CS) and low-dose CsA (target trough levels of 50-100 ng/mL), weaned from month 4 and withdrawn by month 6; daclizumab, MMF, CS and low-dose CsA; or MMF, CS and standard-dose CsA. Mean GFR 12 months after transplantation (primary end point) was not statistically different in the CsA withdrawal and low-dose CsA groups (both 50.9 mL/min/1.73 m(2)) vs. the standard-dose CsA group (48.6 mL/min/1.73 m(2)). At 12 months, the incidence of biopsy-proven acute rejection was significantly higher in the CsA withdrawal group (38%) vs. the low- or standard-dose CsA groups (25.4% and 27.5%, respectively; p < 0.05). In summary, a regimen of continuous low-dose CsA with MMF, CS and daclizumab induction is a clinically safe and effective immunosuppressive regimen in renal transplant recipients.

Cyclosporine: from renal transplantation to autoimmune diseases

Over the last 20 years, cyclosporine (CsA) has been the mainstay of immunosuppression in renal transplantation. Initially, CsA was administered at high doses, which enhanced its potential nephrotoxicity. Better handling of the drug was obtained by lowering the dose, monitoring CsA concentration and renal function, and using graft biopsy in difficult cases. In the early 1990s, a new microemulsion showed better pharmacokinetics and efficacy than did the previous formulation. A few years later, evidence showed that checking blood levels 2 hours after administration was a more reliable indicator of CsA exposure than were trough blood levels. The combination with newer immunosuppressive drugs allowed further reduction in the doses of CsA to maintain stable renal allograft function and to improve long-term graft survival. CsA has largely been used in autoimmune diseases. There is concern about its nephrotoxicity, however, as in some studies control renal biopsies showed that CsA-treated patients developed progressive interstitial fibrosis. The risk of nephrotoxicity was related to the initial doses of CsA and to the increase in serum creatinine. Avoiding CsA in patients with creatinine clearance <60 mL/min and in those with uncontrolled hypertension, starting with CsA microemulsion at doses not higher than 4 mg/kg, and reducing the doses whenever serum creatinine increases to 30% or more over baseline may prevent deterioration of renal function. If these guidelines are followed, CsA may be safely used in autoimmune diseases.

Immunosuppressive agents in solid organ transplantation: Mechanisms of action and therapeutic efficacy

Effective immunosuppression is an essential pre-requisite for successful organ transplantation and improvements in outcome after transplantation have to a large extent been dependent on developments in immunosuppressive therapy. Here we provide an overview of the different immunosuppressive agents currently used in solid organ transplantation. A historical perspective on the development of immunosuppression for organ transplantation is followed by a review of the individual agents, with a focus on their mechanism of action and efficacy. Steroids, anti-proliferative agents (azathioprine and mycophenolate), calcineurin inhibitors (cyclosporine and tacrolimus) and TOR inhibitors (sirolimus and everolimus) are discussed along with both polyclonal and monoclonal antibody preparations. Many of the key clinical trials that underpin current clinical usage of these agents are described and side-effects of the different agents are highlighted. Finally, a number of newer agents still in various stages of clinical development are briefly considered.

Efficacy and cardiovascular safety of daclizumab, mycophenolate mofetil, tacrolimus, and early steroid withdrawal in renal transplant recipients: a multicenter, prospective, pilot trial

This single-arm, open-label, pilot study was designed to assess the efficacy and cardiovascular safety profile of daclizumab, a humanized monoclonal interleukin (IL)-2Ralpha antibody, in combination with mycophenolate mofetil (MMF), tacrolimus, and early corticosteroid withdrawal in renal transplant recipients. Seventy-nine renal allograft recipients were treated with daclizumab (1 mg/kg; five doses starting on the day before transplant and then every two weeks), MMF (1 g b.i.d.), tacrolimus (0.2 mg/kg/d), and low-dose prednisolone, which was withdrawn at day 150 after transplant. The rate of acute rejection was determined at 12 months. Lipid profile, oral glucose tolerance, and adverse events were monitored. Of the 76 patients eligible for analysis, eight (10.5%) developed biopsy-proven acute rejection (BPAR). Ten (13.2%) experienced clinical and/or BPAR. Corticosteroids were withdrawn completely in 91% of patients at 12 months. Graft and patient survival were 97.5% and 98.7% respectively. Mean total cholesterol and triglycerides were significantly lower at 12 months post-transplant than at baseline (201 +/- 47.5 vs. 190.8 +/- 43.6 mg/dL, p = 0.005 and 196.2 +/- 133.2 vs. 144.5 +/- 76.8 mg/dL, p < 0.001, respectively). Mean hemoglobin A1c levels did not differ between baseline (5.54%) and 12 months (5.48%). New-onset post-transplant diabetes mellitus occurred in 6.6% of the non-diabetic transplanted patients. The proportion of patients with abnormal oral glucose tolerance test (OGTT) was 47% at 3 months and 39% at 12 months (p = NS). Daclizumab induction in combination with MMF, tacrolimus, and low-dose (followed by withdrawal) prednisolone appears to be effective and safe in patients receiving renal allografts. The regimen appears to be associated with a favorable cardiovascular profile.

Pathomechanisms and the diagnosis of arterial hypertension in pediatric renal allograft recipients

Arterial hypertension is common in pediatric renal allograft recipients. While the causes are multifactorial, including chronic graft rejection, immunosuppressive therapy, and renal vascular disorders, the effect of hypertension on renal allograft function is detrimental. As in adults, if not treated early and aggressively, hypertension may lead to cardiovascular damage and graft failure. Pathophysiological changes in the arteries and kidney af-ter renal transplantation and the impact of receptor regulation have not been studied extensively in children. For identifying children with hypertension following renal transplantation casual blood pressure measurements do not accurately reflect average arterial blood pressure and circadian blood pressure rhythm. Ambulatory 24-h blood pressure monitoring should regularly be applied in trans-plant patients. The purpose of this review is to analyze pathophysiological aspects of risk factors for arterial hypertension and underline the importance of regular blood pressure monitoring and early therapeutic intervention.

Increased arterial stiffness in cyclosporine-treated lung transplant recipients early after transplantation

BACKGROUND

The majority of patients undergoing solid organ transplantation develop hypertension, to which cyclosporine (CsA)-induced peripheral vasoconstriction may contribute. We hypothesized that CsA-treated transplant recipients have an increased basal vascular tone and an altered response to nitric oxide. To test this hypothesis arterial resistance, non-endothelial dependent relaxation and arterial stiffness were investigated in CsA-treated lung transplant recipients within 18 months after transplantation.

METHODS

In study 1, forearm blood flow (FBF) was measured by venous occlusion plethysmography at baseline and during glyceryl trinitrate (GTN) and N(G)-monomethyl-l-arginine acetate (l-NMMA) infusion in seven lung transplant recipients and nine healthy subjects. In study 2, arterial stiffness in carotid (CCA) and radial artery (RA) was measured by ultrasound (echo-tracking) in 10 lung transplant recipients, 12 healthy subjects and six patients waiting for lung transplantation.

RESULTS

Basal FBF (3.1 +/- 0.2 vs. 3.0 +/- 0.3 mL/min, p = 0.79) and forearm arterial resistance (36 +/- 3 vs. 33 +/- 3 mmHg/mL/min, p = 0.60) did not differ between transplant recipients and controls. GTN infusion increased and l-NMMA decreased blood flow equally in both groups. Transplant recipients had increased arterial stiffness compared to both pre-transplant patients and healthy subjects (CCA stiffness index 11.7 +/- 1.1 vs. 8.5 +/- 0.2 and 8.6 +/- 0.6, p < 0.05 both; RA stiffness index 14.7 +/- 1.5 vs. 8.9 +/- 1.3 and 10.6 +/- 0.7, p < 0.05 both).

CONCLUSIONS

Forearm blood flow and arterial resistance did not differ between healthy subjects and cyclosporine-treated lung transplant recipients early after transplantation. Increased arterial stiffness was demonstrated in transplant recipients, which may have implications for future development of transplant hypertension.

Timing of cardiac transplantation in patients with heart failure receiving β-adrenergic blockers

BACKGROUND

Previous work shows that patients with heart failure patients who have peak oxygen consumption (VO2 peak) >14 ml/kg/min do not derive a survival benefit from cardiac transplantation. However, this was shown before beta-blocker therapy for patients with systolic heart failure became common, and beta-blockers improve survival in patients with heart failure without changing VO(2) peak. Our purpose was to re-evaluate the utility of VO(2) peak >14 ml/kg/min as an indicator of the need for cardiac transplantation in patients with heart failure who are taking beta-blockers.

METHODS

Actuarial, hemodynamic, and exercise ventilatory data were collected from 540 patients with heart failure, 256 of whom were taking beta-blockers. We tracked death and cardiac transplantation. We stratified the percentage of patients event-free 1 and 3 years after VO(2) peak study by their VO(2) peak and beta-blocker status, and compared 1- and 3-year post-transplant survival (United Network of Organ Sharing [UNOS] data). We also compared total mortality for the patients with heart failure as stratified by beta-blocker stats and VO(2) peak (excluding the 42 who underwent transplantation) with UNOS post-transplant survival.

RESULTS

Patients with heart failure who were receiving beta-blockers and whose VO(2) peak was > or =12 ml/kg/min had greater 1- and 3-year event-free survival rates (95% confidence intervals, 92.6%-96.6% and 85.8%-96.0%) than did post-transplant patients (83.9%-86.3% and 75.4%-76.6%). However, in patients with heart failure not taking beta-blockers, VO(2) peak <14 ml/kg/min was associated with worse 3-year survival (38.9 - 62.1%) than that for post-transplant patients. Excluding the 42 patients with heart failure in our study who underwent transplantation and then evaluating survival of the remaining patients with heart failure (not event-free survival) did not substantially change these results.

CONCLUSIONS

Patients with heart failure who are receiving beta-blockers do not derive a survival advantage at 1 and 3 years after cardiac transplantation if VO(2) peak is > or =12 ml/kg/min. Patients not taking beta-blockers whose VO(2) peak is <14 ml/kg/min have superior survival with cardiac transplantation.

A new class of cyclosporin analogues for the treatment of asthma

The disease management of asthma - in particular severe and steroid-resistant asthma - remains a real and daily challenge in the clinic. Cyclosporin A has been a mainstay of immunosuppression therapy in organ transplantation for many years. While its application clearly is efficacious in the inhibition of T-cell proliferation and results in the decrease of inflammatory processes, its side effects in long-term use manifested most prominently through nephrotoxicity have been the main concern against broader use of the drug in inflammatory and immune diseases other than organ transplantation. Several new strategies are currently being pursued to address cyclosporin A toxicity, as summarised in this review. The improved safety profile of novel cyclosporin analogues appear to promise potential new treatments of asthma.

Blood pressure, endothelial function and circulating endothelin concentrations in liver transplant recipients

OBJECTIVES

To study candidates for liver transplant before and 6 weeks after transplant, and to elucidate the role of endothelial dysfunction and plasma endothelin concentrations in the development of hypertension. DESIGN PROSPECTIVE: follow-up study.

SETTING

Institutional, outpatient.

PATIENTS

and controls Fifteen patients (11 men, four women, mean age 46.7+/-13.2 years) with end-stage liver disease (ESLD) and healthy volunteers of comparable age and sex.

METHODS

We performed office blood pressure readings and 24 h ambulatory blood pressure monitoring (ABPM), measurements of endothelial-dependent vasodilatation using high-resolution ultrasound in the brachial artery at rest and during reactive hyperemia, and plasma endothelin-1 assays 3 months before and 6 weeks after the transplant.

RESULTS

Office systolic and diastolic blood pressures increased significantly 6 weeks after liver transplantation (from 116.6+/-14.1 to 139.9+/-19.5 mmHg and from 68.6+/-9.5 to 84.1+/-9.8 mmHg, respectively; both P < 0.001). Hypertension based on office blood pressure readings increased from 6.7 to 40% (P < 0.05). Mean 24 h systolic blood pressure increased from 118.7+/-10.3 to 140.0+/-19.0 mmHg (P < 0.001), mean 24 h diastolic blood pressure increased from 86.0+/-7.7 to 104.8+/-13.9 mmHg (P < 0.001) and heart rate increased from 74.8+/-10.2 to 80.2+/-8.2 beats/min (P < 0.05). Brachial artery flow-mediated dilatation did not change throughout the study (before transplant: 4.2+/-4.0%; after transplant: 6.3+/-5.4%; NS) and did not differ from that in controls (5.2+/-3.8%). Plasma endothelin-1 was increased in patients with ESLD (15.3+/-2.6 pg/ml) compared with controls (5.6+/-0.4 pg/ ml; P < 0.001) and remained unchanged 6 weeks after liver transplantation (14.1+/-3.7 pg/ml).

CONCLUSION

Our results show increased blood pressure with suppressed circadian blood pressure variability in liver graft recipients 6 weeks after transplant and no change in endothelial function and plasma endothelin concentrations. Therefore, the blood pressure increase documented in our study cannot be explained by endothelial dysfunction. Twenty-four hour ABPM should be performed routinely in patients who have undergone liver transplant.

Cyclosporine A and cremophor EL induce contractions of human saphenous vein: involvement of thromboxane A2 receptor-dependent pathway

Chronic treatment with Sandimmune (cyclosporine A [CsA] dissolved in Cremophor EL [CrEL]) is often associated with hypertension and nephrotoxicity. The aims of the present study were to assess the effect of Sandimmune and its two main components (CsA and CrEL) on human saphenous veins and to study the underlying mechanism of their contractile responses. In organ bath, concentration-response curves for Sandimmune (36 ng/ml-120 microg/ml of CsA). CsA (36 ng/ml-120 microg/ml), or CrEL (2.4 microg/ml-8 mg/ml) were elicited in the presence of a thromboxane A2 (TXA2) receptor antagonist (GR32191, 0.3 microM), a cyclooxygenase inhibitor (indomethacin, 1 microM), a 5-lipoxygenase inhibitor (AA861, 10 microM), or their respective vehicles. In addition, the production of TXA2 after CsA challenge was assessed by enzyme immunoassay. Sandimmune, CsA, and CrEL induced concentration-dependent contractions on human saphenous veins. In terms of potency, CsA was a more potent vasoconstrictor agent than CrEL (EC50 values: 11.9+/-3.7 microg/ml (CsA, n = 12) vs. 1.2+/-0.4 mg/ml (CrEL, n = 16), p < 0.05). In contrast, in terms of efficacy, CrEL induced greater contractions than CsA (Emax (% of KCl 90 mM-induced contraction): 98.1+/-16.1% (CrEL, n = 16) vs. 17.0+/-4.3% (CsA, n = 12) p < 0.05). Pretreatment with GR32191 significantly reduced by 85% and 56% the contractions elicited by CsA and CrEL, respectively, whereas indomethacin had no effect. Finally, CsA (12 and 120 microg/ml) failed to stimulate TXA2 production. These in vitro data suggest that Sandimmune-induced contractions on human vascular smooth muscle appear to be mediated by CsA in the therapeutic ranges of doses and by both CsA and CrEL, which, in supratherapeutic doses, acted through a TXA2 receptor-dependent pathway.

Avoidance of cyclosporine in renal transplantation: effects of daclizumab, mycophenolate mofetil, and steroids

Cyclosporine (CsA) has been implicated in both acute and chronic graft dysfunction. The addition of humanized IL-2 receptor antibody daclizumab (DZB) to CsA-based immunosuppression decreases the rate of acute renal transplant rejection. Therefore, 45 patients were evaluated in an immunosuppressive protocol that included DZB, mycophenolate mofetil (MMF), and steroids without CsA. This was a prospective, nonrandomized, open-label trial of the efficacy and safety of the treatment. DZB was given intravenously at 2 mg/kg before transplantation and then at 1 mg/kg every 2 wk for four doses, MMF was given orally at 3 g/d, and methylprednisolone/prednisone was given at 7 mg/kg per day and tapered to 15 mg/d at 6 mo. CsA was added to the regimen when patients developed acute rejection episodes or adverse effects to steroids or MMF; 49% of patients were spared CsA maintenance. Patients without CsA had lower serum creatinine at 6 mo and needed fewer medications to control BP. Incidence of biopsyproven rejections was 31% and occurred early (median, 10 d). These rejection episodes occurred earlier in cadaver transplants (median, 7 d) and later in living donor transplants (median, 62 days). Acute rejections occurred at a higher frequency (46% versus 34%) and earlier (6.5 versus 15 d) in patients with delayed graft function compared with patients without delayed graft function. Most of the rejections were moderate and easily reversible. The actuarial 1-yr graft survival was 95% with 100% patient survival.

The 825C/T polymorphism of the G-protein subunit beta3 does not influence blood pressure and renal function in kidney transplant recipients

BACKGROUND

Recently, a polymorphism at position 825 (C-->T) of the cDNA that encodes the beta3 subunit of heterotrimeric G proteins (Gbeta3) was found to be associated with essential hypertension. The T allele leads to the formation of a truncated splice variant (Gbeta3-s) with enhanced activity, promoting hypertension. We examined whether the T allele had an influence on blood pressure (BP) and early renal function after renal transplantation.

METHODS

We determined the Gbeta3 genotype and T allele frequencies in renal transplant patients and examined associations with BP, BP medications, and renal function in the first year after transplantation.

RESULTS

In renal transplant recipients (n=216) the frequency of the T allele was marginally increased (0.34 vs 0.29) compared with normal healthy blood donors (n=163). Age, sex and body mass index were similar in patients with the CC, CT and TT genotype. BP, number of BP medications, and serum creatinine levels were also similar for the three genotypes within the first year after transplantation. Significantly more patients with the TT genotype (48%) had glomerulonephritis as the underlying renal disease, compared with the CT (29%) and CC (27%) genotypes.

CONCLUSIONS

The T allele of Gbeta3 does not have a negative impact on BP and early renal function in recipients of a renal allograft. The T allele might play a role in the pathogenesis of chronic glomerulonephritides.

Prospective analysis of the value of 24-hour ambulatory blood pressure on renal function after kidney transplantation

BACKGROUND

No prospective study has been performed to determine the prognostic value of 24-hr ambulatory blood pressure (24-hr ABP) versus casual blood pressure (CBP) in patients after kidney transplantation. We have addressed this issue by analyzing renal graft function in patients for the first 5 years after transplantation.

METHODS

The 24-hr ABP (SpaceLabs 90207) was monitored 6 and 18 months after transplantation in 46 renal transplant recipients without any acute episodes of rejection. Combined study endpoints were death of patients, need for dialysis, second transplantation, and doubling of serum creatinine.

RESULTS

Six months after transplantation systolic and diastolic 24-hr ABP correlated with serum creatinine (r=0.41, P=0.005 and r=0.37, P<0.01, respectively) although CBP did not. Divided into tertiles according to average 24-hr ABP (lower tertile: < or =91 mmHg; middle tertile: 92-97 mmHg; upper tertile: > or =98 mmHg) serum creatinine significantly differed between the three groups (1.26 +/- 0.38 vs. 1.32 +/- 0.25 vs. 1.65 +/- 0.39 mg/dl, respectively; analysis of variance, P< 0.01). Confounding factors of renal function such as age, body weight, cold and warm ischemic time, cytomegaly virus status, methylprednisone and cyclosporine dosages, cyclosporine concentrations, as well as concomitant antihypertensive medication did not differ among the three groups. In the long-term follow-up (5 years), combined endpoints were reached in 3 of 15 of the lower tertile group, in 3 of 15 of the median tertile group, and in 8 of 16 of the upper tertile group (log-rank test, P<0.01). No relation to long-term out come was found when patients were stratified according to their CBP.

CONCLUSION

In our small but homogenous study cohort 24-hr ABP was more closely related to renal function in patients after transplantation than CBP suggesting that 24-hr ABP is superior for evaluation of hypertension-related renal graft dysfunction.

Ambulatory blood pressure monitoring in children with aortic coarctation and kidney transplantation

BACKGROUND

Ambulatory blood pressure monitoring (ABPM) has been found to be of significant importance in clinical practice because numerous blood pressure (BP) measurements may be made throughout the 24-hour period.

OBJECTIVE

To assess the clinical utility of ABPM in children with secondary hypertension.

METHODS

We studied 37 patients (21 boys and 16 girls), with a mean age of 16.4 +/- 4.1 years, after kidney transplantation and 38 patients (27 boys and 11 girls), with a mean age of 10.2 +/- 2.1 years, after surgical correction of aortic coarctation. Data, expressed as mean +/- SD, were analyzed after dividing the patients into 4 groups. Group A consisted of 25 patients receiving antihypertensive therapy; group B included 12 patients not receiving antihypertensive therapy. Group C included 25 patients operated on before 3 years of age (8 +/- 7 months of age); group D included 13 patients operated on after 3 years of age (74 +/- 29 months of age).

RESULTS

In groups A and B, casual BP measurement showed that 16 of 37 patients (43%) were hypertensive; 24-hour ABPM detected a larger number of patients who were hypertensive (23 of 37, 62%); there were 18 in group A and 5 in group B. In groups C and D, casual BP measurement identified 6 of 38 (15%) patients as hypertensive, whereas 24-hour ABPM again identified a higher number (13 of 38, 34%).

CONCLUSIONS

Our findings confirm that 24-hour ABPM is more sensitive than casual BP in detecting abnormal BP in patients at high risk for secondary hypertension.

Endothelial dysfunction in renal transplant recipients maintained on cyclosporine

BACKGROUND

Hypertension is almost universal following renal transplantation and may contribute to the already poor cardiovascular prognosis of this group. Cyclosporine-induced hypertension is a particular problem and has variously been attributed to increased sympathetic nerve activity, salt and water retention, and increased circulating endothelin levels. However, the effects of cyclosporine on the L-arginine/nitric oxide (NO) system in vivo in humans are unknown. In this present study, we examined basal and stimulated NO production from the vascular endothelium in cyclosporine-treated renal transplant recipients using the technique of forearm venous plethysmography.

METHODS

In study 1, stimulated NO production was assessed in 9 cyclosporine-treated renal transplant recipients (CsA), 7 azathioprine-treated renal transplant recipients (AZA), and 12 controls, using carbachol (an endothelium-dependent vasodilator) and sodium nitroprusside (an endothelium-independent vasodilator). In study 2, basal NO production was assessed in 9 cyclosporine-treated patients and 11 controls using L-NMMA (inhibits NO synthase), with norepinephrine as a control vasoconstrictor. Drugs were infused into the nondominant forearm through a sterile 27-gauge needle, and changes in forearm blood flow (FBF) were measured using venous occlusion plethysmography.

RESULTS

In study 1, sodium nitroprusside caused a similar dose-dependent increase in FBF in all groups. However, the median (range) percentage increase FBF to carbachol (3 micrograms/min) was markedly reduced in the CsA patients (188.8; 72.5 to 385.1) compared with AZA patients (378.1; 124.0 to 548.9; P = 0.042) and to controls (303.8; 124.8 to 813.3; P = 0.028). In study 2, the maximum percentage reduction in FBF to L-NMMA (4 mumol/min) was less pronounced in CsA patients (-19.5; -4.7 to -63.1) compared with controls (-39.5; -15.7 to -52.8; P = 0.056), and while controls vasoconstricted to the maximum dose of norepinephrine (240 pmol/min) as expected (-26.9; -1.4 to -38.6), CsA patients as a group tended to vasodilate (7.9; -36.8 to 92.6; P = 0.02).

CONCLUSION

These data demonstrate impaired stimulated and basal NO production in CsA patients, indicating endothelial dysfunction. This may predispose patients to atherosclerosis and may be involved in the etiology of post-transplant hypertension.

Forearm vasorelaxation in hypertensive renal transplant patients: the impact of withdrawal of cyclosporine

OBJECTIVE

To determine whether cyclosporine A-induced hypertension in renal transplant recipients is accompanied by impairment of endothelium-dependent vasodilatation, which has been suggested by in-vitro and in-vivo animal experiments.

DESIGN AND METHODS

In-vivo endothelium-dependent and endothelium-independent vasodilatation, and plasma concentrations of vasoactive hormones in 16 renal transplant patients were determined while they were being treated with cyclosporine A, and 16 weeks later, after their treatment had been changed to azathioprine therapy. The vasodilator response of the forearm vascular bed was measured by strain gauge venous occlusion plethysmography during intra-arterial infusion of acetylcholine (endothelium-dependent vasodilatation) and nitroprusside (endothelium-independent vasodilatation). Postischemic reactive flow was measured after 10 min of arterial occlusion. In addition, plasma concentrations of norepinephrine, and the prostanoids prostaglandin E2 and thromboxane B2, and also concentration of cyclosporine A in blood, were measured. Glomerular filtration rate and renal blood flow were estimated 1 day before the plethysmography study during each treatment period.

RESULTS

Upon changing from cyclosporine A to azathioprine treatment, mean arterial pressure fell significantly by 12+/-3% (P< 0.05). Glomerular filtration rate and renal blood flow increased by 13+/-5 and 19+/-8%, respectively (both P< 0.05), while renal vascular resistance fell by 48+/-11% (P< 0.01). Both baseline forearm blood flow and baseline forearm resistance did not change after conversion (5.7+/-0.7 versus 4.9+/-0.6 ml/100 ml/min, and 27.3+/-4.2 versus 26.2+/-3.2 arbitrary units). The absolute and relative forearm blood flow responses, and forearm vascular resistance responses to infusions of acetylcholine and nitroprusside were similar during treatments with cyclosporine A and azathioprine. Peak postischaemic forearm blood flow was 42+/-12% higher during cyclosporine A treatment than it was during azathioprine treatment (P< 0.05), but the minimal postischaemic forearm vascular resistance did not differ for these treatments. Plasma prostaglandin E2 and thromboxane B2 levels decreased by 34+/-7 and 45+/-8%, respectively, after changing treatment, but norepinephrine levels did not change.

CONCLUSIONS

Our data indicate that cyclosporine A-induced hypertension in renal transplant recipients is not accompanied by an increase in forearm vascular resistance. In addition, changing from cyclosporine A to azathioprine treatment did not cause changes in endothelial vasodilator functioning, although mean arterial pressure decreased significantly. Our results do not support the hypothesis that attenuation of endothelial vasodilator functioning contributes to the development of cyclosporine A-induced hypertension.

Side effects of immunosuppressant therapies used in neurology

This article provides an overview of the clinically relevant complications of the main immunosuppressants currently used in the treatment of neurologic disorders with suspected or established immune etiology. The most serious complications are discussed in detail, including pathophysiology and preventative measures. An intimate knowledge of these complications proves helpful in the day to day practice of the neurologist supervising immunotherapy.