Calcineurin inhibitors in heart transplantation

Association Between Circulating Regulator of Calcineurin 2 Concentrations With Overweight and Obesity

BACKGROUND

Regulator of calcineurin 2 (RCAN2) has been reported to promote food intake and weight gain in animal studies. However, its effect on body weight in humans is unclear.

OBJECTIVE

This study aimed to investigate the relationship between serum RCAN2 concentrations and participants with overweight/obesity.

METHODS

A cross-sectional study was performed in 872 Chinese adults, including 348 participants with normal weight (NW), 397 participants with overweight (OW), and 127 participants with obesity (OB). All participants were divided into NW, OW and OB groups according to their body mass index (BMI). Serum RCAN2 concentrations were determined by enzyme-linked immunosorbent assay.

RESULTS

Serum RCAN2 concentrations gradually increased with the increase of BMI (p < 0.001). The percentages of OW/OB gradually increased in tandem with increasing tertiles of RCAN2 (p < 0.001). Additionally, serum RCAN2 concentrations were significantly correlated with a series of anthropometric and metabolic parameters, predominantly including body weight, BMI, SBP, DBP, total cholesterol, triglycerides, HDL-C, LDL-C (all p < 0.05). Furthermore, logistic regression analysis showed that the risk of OW/OB was significantly increased with the increase of serum RCAN2 concentrations. Receiver operation characteristic (ROC) curve analysis revealed that serum RCAN2, especially serum RCAN2/(AST/ALT) ratio, might serve as a candidate biomarker for obesity.

CONCLUSION

Serum RCAN2 concentrations were increased in subjects with OW/OB. The increased serum RCAN2 concentrations were associated with the increased risks of OW/OB.

Steroid withdrawal after heart transplantation in adults

Corticosteroids (CSs) are a key component of immunosuppressive treatment after heart transplantation (HTx). While effectively preventing acute rejection, several adverse effects including diabetes, hypertension, osteoporosis, and hyperlipidemia are associated with long-term use. As these complications may impair long-term outcome in HTx recipients, withdrawal of CSs is highly desirable, however, no uniform approach exists. Previous experience suggests that CS withdrawal can be accomplished without an increase in the incidence of acute rejection and even carrying a survival benefit. Also, common complications related to long-term CS use appear to be less frequent following CS discontinuation. Recipients who successfully discontinue CSs, however, likely belong to an immune-privileged subset of patients with low risk of post-transplant complications. Available studies evaluating CS withdrawal are highly heterogeneous and consensus on optimal timing and eligibility for withdrawal is lacking. Efforts to improve the understanding of optimal CS withdrawal strategy are of great importance in order to safely promote CS weaning in eligible patients and thereby alleviate the adverse effects of long-term CS use on post-transplant outcomes. The purpose of this review was to evaluate different protocols of CS withdrawal after HTx in terms of clinical outcomes and to explore criteria for successful CS withdrawal.

Calcineurin Inhibitor Toxicity in Solid Organ Transplantation

Calcineurin inhibitors (CNIs) have a substantial role in maintaining immunosuppression after solid organ transplantation (SOT). These drugs have a narrow therapeutic window, and individual doses and drug treatment monitoring are necessary. Still, a substantial proportion of patients suffer from short- or long-term calcineurin inhibitor toxicity (CNT), including kidney function impairment, hypertension, neurotoxicity, and metabolic disturbances. The authors discuss pathophysiology, clinical presentation, and histological features of CNT, with focus on renal manifestations. Furthermore, we elucidate recent and ongoing attempts to reduce the burden of CNT in SOT including CNI-sparing and CNI-free regimens.

Graft IL-33 regulates infiltrating macrophages to protect against chronic rejection

Alarmins, sequestered self-molecules containing damage-associated molecular patterns, are released during tissue injury to drive innate immune cell proinflammatory responses. Whether endogenous negative regulators controlling early immune responses are also released at the site of injury is poorly understood. Herein, we establish that the stromal cell-derived alarmin interleukin 33 (IL-33) is a local factor that directly restricts the proinflammatory capacity of graft-infiltrating macrophages early after transplantation. By assessing heart transplant recipient samples and using a mouse heart transplant model, we establish that IL-33 is upregulated in allografts to limit chronic rejection. Mouse cardiac transplants lacking IL-33 displayed dramatically accelerated vascular occlusion and subsequent fibrosis, which was not due to altered systemic immune responses. Instead, a lack of graft IL-33 caused local augmentation of proinflammatory iNOS+ macrophages that accelerated graft loss. IL-33 facilitated a metabolic program in macrophages associated with reparative and regulatory functions, and local delivery of IL-33 prevented the chronic rejection of IL-33-deficient cardiac transplants. Therefore, IL-33 represents what we believe is a novel regulatory alarmin in transplantation that limits chronic rejection by restraining the local activation of proinflammatory macrophages. The local delivery of IL-33 in extracellular matrix-based materials may be a promising biologic for chronic rejection prophylaxis.

Programmed necrosis in cardiomyocytes: mitochondria, death receptors and beyond

Excessive death of cardiac myocytes leads to many cardiac diseases, including myocardial infarction, arrhythmia, heart failure and sudden cardiac death. For the last several decades, most work on cell death has focused on apoptosis, which is generally considered as the only form of regulated cell death, whereas necrosis has been regarded to be an unregulated process. Recent findings reveal that necrosis also occurs in a regulated manner and that it is closely related to the physiology and pathophysiology of many organs, including the heart. The recognition of necrosis as a regulated process mandates a re-examination of cell death in the heart together with the mechanisms and therapy of cardiac diseases. In this study, we summarize the regulatory mechanisms of the programmed necrosis of cardiomyocytes, that is, the intrinsic (mitochondrial) and extrinsic (death receptor) pathways. Furthermore, the role of this programmed necrosis in various heart diseases is also delineated. Finally, we describe the currently known pharmacological inhibitors of several of the key regulatory molecules of regulated cell necrosis and the opportunities for their therapeutic use in cardiac disease. We intend to systemically summarize the recent progresses in the regulation and pathological significance of programmed cardiomyocyte necrosis along with its potential therapeutic applications to cardiac diseases. LINKED ARTICLES: This article is part of a themed section on Mitochondrial Pharmacology: Featured Mechanisms and Approaches for Therapy Translation. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.22/issuetoc.

Hurdles to Cardioprotection in the Critically Ill

Cardiovascular disease is the largest contributor to worldwide mortality, and the deleterious impact of heart failure (HF) is projected to grow exponentially in the future. As heart transplantation (HTx) is the only effective treatment for end-stage HF, development of mechanical circulatory support (MCS) technology has unveiled additional therapeutic options for refractory cardiac disease. Unfortunately, despite both MCS and HTx being quintessential treatments for significant cardiac impairment, associated morbidity and mortality remain high. MCS technology continues to evolve, but is associated with numerous disturbances to cardiac function (e.g., oxidative damage, arrhythmias). Following MCS intervention, HTx is frequently the destination option for survival of critically ill cardiac patients. While effective, donor hearts are scarce, thus limiting HTx to few qualifying patients, and HTx remains correlated with substantial post-HTx complications. While MCS and HTx are vital to survival of critically ill cardiac patients, cardioprotective strategies to improve outcomes from these treatments are highly desirable. Accordingly, this review summarizes the current status of MCS and HTx in the clinic, and the associated cardiac complications inherent to these treatments. Furthermore, we detail current research being undertaken to improve cardiac outcomes following MCS/HTx, and important considerations for reducing the significant morbidity and mortality associated with these necessary treatment strategies.

Regulated necrosis in kidney ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) is the outcome of an inflammatory process that is triggered when an organ undergoes a transient reduction or cessation of blood flow, followed by re-establishment of perfusion. In the clinical setting, IRI contributes to significant acute kidney injury, patient morbidity and mortality, and adverse outcomes in transplantation. Tubular cell death by necrosis and apoptosis is a central feature of renal IRI. Recent research has challenged traditional views of cell death by identifying new pathways in which cells die in a regulated manner but with the morphologic features of necrosis. This regulated necrosis (RN) takes several forms, with necroptosis and ferroptosis being the best described. The precise mechanisms and relationships between the RN pathways in renal IRI are currently the subject of active research. The common endpoint of RN is cell membrane rupture, resulting in the release of cytosolic components with subsequent inflammation and activation of the immune system. We review the evidence and mechanisms of RN in the kidney following renal IRI, and discuss the use of small molecule inhibitors and genetically modified mice to better understand this process and guide potentially novel therapeutic interventions.

Everolimus immunosuppression for renal protection, reduction of allograft vasculopathy and prevention of allograft rejection in de-novo heart transplant recipients: could we have it all?

PURPOSE OF REVIEW

De-novo introduction of everolimus (Eve) in heart transplant recipients opens for early reduction of calcineurin inhibitors (CNI) and potential of preserving renal function, attenuate progression of coronary allograft vasculopathy (CAV) and maintain rejection efficacy.

RECENT FINDINGS

The first trials demonstrated adequate rejection prophylaxis and favorable outcomes on CAV, but observed enhanced nephrotoxicity because of insufficient CNI reduction. The SCHEDULE trial compared de-novo Eve with significantly reduced CNI exposure and conversion to CNI-free treatment week 7-11 postheart transplant, with standard CNI immunosuppression. Improved renal function and attenuation of CAV was found among Eve patients, with higher numbers of treated acute rejections observed. With sustained superior renal and CAV related data also after 36 months with the Eve protocol, cardiac function was equally well preserved in both groups. According to the International Society of Heart and Lunge Transplantation registry, mammalian target of rapamycin inhibitor treatment is uncommon during the first postoperative year, with a prevalence of 20% in patients after 5 years.

SUMMARY

Current evidence suggests a greater benefit from these immunosuppressives if introduced at an earlier timepoint. Immunosuppressive protocols based on Eve treatment in de-novo patients should be further investigated and developed, enabling CNI avoidance before accelerating side-effects lead to irreversible damage.

The CECARI Study: Everolimus (Certican®) Initiation and Calcineurin Inhibitor Withdrawal in Maintenance Heart Transplant Recipients with Renal Insufficiency: A Multicenter, Randomized Trial

In this 3-year, open-label, multicenter study, 57 maintenance heart transplant recipients (>1 year after transplant) with renal insufficiency (eGFR 30–60 mL/min/1.73 m²) were randomized to start everolimus with CNI withdrawal (N = 29) or continue their current CNI-based immunosuppression (N = 28). The primary endpoint, change in measured glomerular filtration rate (mGFR) from baseline to year 3, did not differ significantly between both groups (+7.0 mL/min in the everolimus group versus +1.9 mL/min in the CNI group, p = 0.18). In the on-treatment analysis, the difference did reach statistical significance (+9.4 mL/min in the everolimus group versus +1.9 mL/min in the CNI group, p = 0.047). The composite safety endpoint of all-cause mortality, major adverse cardiovascular events, or treated acute rejection was not different between groups. Nonfatal adverse events occurred in 96.6% of patients in the everolimus group and 57.1% in the CNI group (p < 0.001). Ten patients (34.5%) in the everolimus group discontinued the study drug during follow-up due to adverse events. The poor adherence to the everolimus therapy might have masked a potential benefit of CNI withdrawal on renal function.

Regulated necrosis: disease relevance and therapeutic opportunities

The discovery of regulated cell death presents tantalizing possibilities for gaining control over the life-death decisions made by cells in disease. Although apoptosis has been the focus of drug discovery for many years, recent research has identified regulatory mechanisms and signalling pathways for previously unrecognized, regulated necrotic cell death routines. Distinct critical nodes have been characterized for some of these alternative cell death routines, whereas other cell death routines are just beginning to be unravelled. In this Review, we describe forms of regulated necrotic cell death, including necroptosis, the emerging cell death modality of ferroptosis (and the related oxytosis) and the less well comprehended parthanatos and cyclophilin D-mediated necrosis. We focus on small molecules, proteins and pathways that can induce and inhibit these non-apoptotic forms of cell death, and discuss strategies for translating this understanding into new therapeutics for certain disease contexts.

The Effect of Everolimus Initiation and Calcineurin Inhibitor Elimination on Cardiac Allograft Vasculopathy in De Novo Recipients: One-Year Results of a Scandinavian Randomized Trial

Early initiation of everolimus with calcineurin inhibitor therapy has been shown to reduce the progression of cardiac allograft vasculopathy (CAV) in de novo heart transplant recipients. The effect of de novo everolimus therapy and early total elimination of calcineurin inhibitor therapy has, however, not been investigated and is relevant given the morbidity and lack of efficacy of current protocols in preventing CAV. This 12-month multicenter Scandinavian trial randomized 115 de novo heart transplant recipients to everolimus with complete calcineurin inhibitor elimination 7-11 weeks after HTx or standard cyclosporine immunosuppression. Ninety-five (83%) patients had matched intravascular ultrasound examinations at baseline and 12 months. Mean (± SD) recipient age was 49.9 ± 13.1 years. The everolimus group (n = 47) demonstrated significantly reduced CAV progression as compared to the calcineurin inhibitor group (n = 48) (ΔMaximal Intimal Thickness 0.03 ± 0.06 and 0.08 ± 0.12 mm, ΔPercent Atheroma Volume 1.3 ± 2.3 and 4.2 ± 5.0%, ΔTotal Atheroma Volume 1.1 ± 19.2 mm(3) and 13.8 ± 28.0 mm(3) [all p-values ≤ 0.01]). Everolimus patients also had a significantly greater decline in levels of soluble tumor necrosis factor receptor-1 as compared to the calcineurin inhibitor group (p = 0.02). These preliminary results suggest that an everolimus-based CNI-free can potentially be considered in suitable de novo HTx recipients.

Comparison of MMF with prednisone in terms of rejection and duration of activity of transplant in rabbits that underwent retroperitoneal heterotopic heart transplantation

AIM

In this study, mycophenolate mofetil (MMF) and methylprednisolone (MP) were compared in terms of rejection and duration of activity of the transplant in New Zealand rabbits that underwent retroperitoneal heart transplantation.

METHODS

Retroperitoneal heart transplantation was performed in New Zealand white rabbits. The animals were divided into two groups. MMF group (group 1) (10 donors, 10 recipients): 12.5 mg/kg MMF was administered orally for two days prior to the surgery; MP group (group 2) (nine donors, nine recipients): 2 mg/kg MP was administered intramuscularly for two days prior to the surgery. After the operation, we waited until all motor activity in the transplanted heart had stopped. The transplant was then removed and the recipient was sacrificed. A donor in the MP group was excluded since it died before the motor activity had stopped.

RESULTS

No statistically significant difference was found between the groups in terms of rejection score (p = 0.865). However, duration of motor activity was found to be statistically significantly longer in the MMF group, compared to the MP group (p = 0.013).

CONCLUSION

In this experimental study, MMF was similar to MP in terms of rejection but had better efficacy in terms of duration of motor activity of the transplant.

Cellular effects of everolimus and sirolimus on podocytes

Everolimus (EVL) and Sirolimus (SRL) are potent immunosuppressant agents belonging to the group of mammalian target of rapamycin (mTOR) inhibitors used to prevent transplant rejection. However, some patients develop proteinuria following a switch from a calcineurin inhibitor regimen to mTOR inhibitors. Whether different mTOR inhibitors show similar effects on podocytes is still unknown. To analyze this, human podocytes were incubated with different doses of EVL and SRL. After incubation with EVL or SRL, podocytes revealed a reduced expression of total mTOR. Phosphorylation of p70S6K and Akt was diminished, whereas pAkt expression was more reduced in the SRL group. In both groups actin cytoskeletal reorganization was increased. Synaptopodin and podocin expression was reduced as well as nephrin protein, particularly in the SRL group. NFκB activation and IL-6 levels were lower in EVL and SRL, and even lower in SRL. Apoptosis was more increased in SRL than in the EVL group. Our data suggests that mTOR inhibitors affect podocyte integrity with respect to podocyte proteins, cytoskeleton, inflammation, and apoptosis. Our study is the first to analyze both mTOR inhibitors, EVL and SRL, in parallel in podocytes. Partially, the impact of EVL and SRL on podocytes differs. Nevertheless, it still remains unclear whether these differences are of relevance regarding to proteinuria in transplant patients.

Myocardial infarction in an adult with cystic fibrosis and heart and lung transplant

We present a case of myocardial infarction in a 19 year old female with cystic fibrosis who had a heart and lung transplant performed at the age of four years old. She presented atypically with a one day history of severe, intermittent, central, sharp chest pain, radiating to her back and down her left arm. A coronary angiogram showed proximal stenosis of the left anterior descending artery and right coronary artery. She was treated with percutaneous coronary intervention, involving drug eluting stents to the left anterior descending artery (LAD) and the right coronary artery (RCA). In this study we discuss the pathophysiology, investigations and treatment of cardiac transplant vasculopathy. Although complete reversal of LAD and RCA stenosis was achieved, routine follow-up with coronary angiography and careful control of cardiac risk factors will be important to identify and reduce future restenosis and adverse cardiac events.

Efficacy and safety of low-dose everolimus as maintenance immunosuppression in cardiac transplant recipients

For cardiac transplant (CTx) recipients, the recommended everolimus (EVL) dose is 0.75 mg bid or 1.5 mg bid and the target trough blood level is 3–8 μg/L. We studied a cohort of 56 CTx patients with chronic kidney disease receiving 0.75 mg bid EVL to maintain blood levels of 5–8 ug/L (designated RD group) and a cohort of 51 CTx patients with chronic kidney disease receiving 0.5 mg bid to maintain blood levels of 3–5 ug/L (designated LD group). The primary endpoint was a composite of death, rejection and premature EVL discontinuation up to 1 year after introduction of EVL. The primary endpoint was reached by 32% of patients in the LD group and by 41.1% of patients in the RD group (P = 0.361). Biochemical safety parameters were comparable in both groups. Our results indicate that low-dose EVL may be as effective and safe as regular dose EVL.

Primary immunosuppression and outcome differences after heart transplantation: tacrolimus versus cyclosporine

BACKGROUND

The superiority of tacrolimus (Tac) as primary immunosuppression for heart transplantation (HT) compared with cyclosporine (CsA) is still under debate. Outcomes of comparison studies are not consistent; the duration of these studies has been limited. The aim of this study was to evaluate long-term outcomes of patients undergoing HT based on primary immunosuppression regime.

METHODS AND RESULTS

We analyzed a single-center registry of all HT patients between 1998 and 2009, comparing outcomes based on primary immunosuppressions (Tac or CsA). Patients who died before starting immunosuppression were excluded. A total of 197 patients entered the study; 103 received Tac and 94 CsA. There were no differences between groups in baseline characteristics, United Network for Organ Sharing status 1A or ventricular assist device use, except for ischemia time (195 ± 50 min in Tac group vs 182 ± 55 min in CsA; P = .08) and days on waiting list (164 ± 155 vs 100 ± 73; P < .001). After mean follow-ups of 4.5 ± 2.3 years in the Tac group and 6.3 ± 4.3 years in the CsA group, there were 19 and 36 deaths, respectively. Kaplan-Meier analysis showed increased survival for the Tac group (log rank P = .04). Tac also was significantly superior to CsA regarding mortality (relative risk 0.55; 95% confidence interval, 0.31-0.98; P = .04).

CONCLUSIONS

In our series the use of tacrolimus resulted in improved long-term survival compared with cyclosporine. At 1-year follow-up, there were no differences in acute rejection episodes or the appearance of vasculopathy.

Calcineurin inhibitor-free immunosuppression using everolimus (Certican) after heart transplantation: 2 years' follow-up from the University Hospital Münster

BACKGROUND

Everolimus is a proliferation-signal inhibitor which was introduced for heart transplant recipients in 2004. To date, there are only sparse data about long-term calcineurin inhibitor (CNI)-free immunosuppression using everolimus.

METHODS

After heart transplantation, patients receiving everolimus were consecutively enrolled. Reasons for switching to everolimus were side effects of CNI immunosuppression, such as deterioration of kidney function and recurrent rejection episodes. All 60 patients underwent standardized switching protocols, 42 patients completed 24-month follow-up. Blood was sampled for lipid status, renal function, routine controls, and levels of immunosuppressive agents. On days 0, 14, and 28, and then every 3 months, echocardiography and physical examination were performed.

RESULTS

After switching to everolimus, most patients recovered from the side effects. Renal function improved significantly after 24 months (creatinine, 2.1 ± 0.6 vs 1.8 ± 1 mg/dL; P < .001; creatinine clearance, 41.8 ± 22 vs 48.6 ± 21.8 mL/min; P < .001). Median blood pressure increased from 120.0/75.0 mm Hg at baseline to 123.8/80.0 mm Hg at month 24 (P values .008 and .003 for systolic and diastolic pressures, respectively). Tremor, peripheral edema, hirsutism, and gingival hyperplasia markedly improved. Levels of interleukin-6 were stable between baseline and 24-month levels. Temporary adverse events occurred in 8 patients [13.3%: interstitial pneumonia (n = 2), skin disorders (n = 2); reactivated hepatitis B (n = 1), and fever of unknown origin (n = 3)].

CONCLUSION

CNI-free immunosuppression using everolimus is safe, with excellent efficacy in maintenance of heart transplant recipients. Arterial hypertension and renal function significantly improved. CNI-induced side effects, such as tremor, peripheral edema, hirsutism, and gingival hyperplasia, markedly improved in most patients.

Prospective study of everolimus with calcineurin inhibitor-free immunosuppression in maintenance heart transplant patients: results at 2 years

BACKGROUND

Few studies have examined everolimus therapy with calcineurin inhibitor (CNI) withdrawal in maintenance heart transplant patients.

METHODS

In a prospective, single-arm, single-center study, CNI-treated heart transplant patients were converted to everolimus and were followed up for 24 months. The primary endpoints were kidney function and arterial hypertension at 12 and 24 months after conversion.

RESULTS

Fifty-eight patients were recruited (mean time posttransplant 5.6±3.7 years), 55 of whom (91.7%) had renal impairment. Mean creatinine clearance increased from 43.6±21.1 mL/min to 49.5±21.2 mL/min at month 24 (P=0.02). Median blood pressure increased from 120/80 mm Hg at baseline to 122.5/80 mm Hg (P=0.008 and 0.006 for systolic and diastolic pressure, respectively). Lipid parameters did not change significantly over the 24-month follow-up. Early resolution of most non-renal CNI-related adverse events was sustained. CNI therapy was re-introduced at a mean of 309 days (range, 31-684 days) in eight patients after month 6 due to adverse events (n=13) or withdrawal of consent (n=2). No significant changes in cardiac function parameters were observed.

CONCLUSIONS

CNI-free immunosuppression with everolimus is an effective and safe option in selected heart transplant maintenance patients. Most adverse effects under everolimus occurred early after conversion and generally resolved without intervention within a few weeks. Refining selection criteria may reduce the need to re-introduce CNI therapy.

Differential effects of acute and sustained cyclosporine and tacrolimus on sympathetic nerve activity

BACKGROUND

We studied the effect of acute and sustained cyclosporine and tacrolimus on muscle sympathetic nerve activity (MSNA) in groups of healthy male volunteers.

METHODS AND RESULTS

Acute cyclosporine in normal dose (2.5 mg/kg) increased MSNA from 11 +/- 6 to 19 +/- 8 bursts/min (P < 0.05). Acute cyclosporine in high dose (10 mg/kg) increased MSNA from 13 +/- 6 to 25 +/- 4 bursts/min (P < 0.05) and increased heart rate and mean arterial pressure (heart rate from 64 +/- 8 to 74 +/- 6 b.p.m., MAP from 92 +/- 10 to 105 +/- 8 mmHg; both P < 0.05). Sustained cyclosporine (2.5 mg/kg b.i.d. for 2 weeks) suppressed MSNA from 14 +/- 6 to 8 +/- 7 bursts/min (P < 0.05). Blood pressure increased from 89 +/- 6 to 98 +/- 6 mmHg (P < 0.05). Body weight increased and plasma renin activity was suppressed. Acute tacrolimus in regular dose (0.05 mg/kg) and high dose (0.20 mg/kg) had no effect on MSNA and blood pressure. Sustained tacrolimus (0.05 mg/kg b.i.d. for 2 weeks) had no effect on blood pressure, body weight and plasma renin activity, but decreased MSNA from 14 +/- 6 to 8 +/- 5 bursts/min (P < 0.05).

CONCLUSION

Sympathetic overactivity plays a role in the acute hypertensive action of cyclosporine. Cyclosporine given during 2 weeks increases blood pressure and suppresses MSNA, possibly by volume retention. Tacrolimus, in the presently applied dosages, does not cause hypertension or sympathetic overactivity. However, sustained tacrolimus also suppresses sympathetic activity, the reason of which is unclear.

Regulatory properties of polysaccharopeptide derived from Coriolus versicolor and its combined effect with ciclosporin on the homeostasis of human lymphocytes

OBJECTIVES

Lymphocyte homoeostasis is essential in inflammatory and autoimmune diseases. In search of natural fungal metabolites with effects on lymphocyte homoeostasis, we recently reported that polysaccharopeptide (PSP) from Coriolus versicolor exhibited ciclosporin-like activity in controlling aberrant lymphocyte activation. This object of this study was to investigate its effect on lymphocyte homoeostasis. This was done by investigating the mechanistic actions of PSP in relation to ciclosporin by performing cell cycle and cell death analysis of human lymphocytes in vitro.

METHODS

We investigated the effect of PSP in the presence and absence of ciclosporin on cell proliferation, cell cycle, cell death, immunophenotype and cell cycle regulatory proteins in human lymphocytes.

KEY FINDINGS

The data showed that PSP exhibited homoeostatic activity by promoting and inhibiting the proliferation of resting and phytohaemagglutinin (PHA)-stimulated lymphocytes, respectively. PHA-stimulated lymphocytes exhibited G0/G1 cell cycle arrest that was accompanied by a reduction of cyclin E expression with PSP treatment. Both PSP and ciclosporin blocked the reduction of the CD4/CD8 ratio in stimulated lymphocytes. PSP did not induce cell death in human lymphocytes, but the suppression of the Fasreceptor suggested a protective role of PSP against extrinsic cell death signals. These homoeostatic effects were more potent with combined PSP and ciclosporin treatment than with either fungal metabolite alone.

CONCLUSIONS

Collectively, the results reveal certain novel effects of PSP in lymphocyte homoeostasis and suggest potential as a specific immunomodulatory adjuvant for clinical applications in the treatment of autoimmune diseases.

Dangerous drug interactions leading to hemolytic uremic syndrome following lung transplantation

Background

To report our experience of a rather uncommon drug interaction, resulting in hemolytic uremic syndrome (HUS).

Methods

Two consecutive cases of hemolytic uremic syndrome were diagnosed in our service. In both patients the use of macrolides in patients taking Tacrolimus, resulted in high levels of Tacrolimus.

Results

The first patient was a 48 years old female with Bilateral emphysema. She underwent Single Sequential Lung Transplantation. She developed reperfusion injury requiring prolonged stay. Tacrolimus introduced (Day 51). The patient remained well up till 5 months later; Erythromycin commenced for chest infection. High Tacrolimus levels and a clinical diagnosis of HUS were made. She was treated with plasmapheresis successfully.

The second case was a 57 years old female with Emphysema & A1 Antithrypsin deficiency. She underwent Right Single Lung Transplantation. A2 rejection with mild Obliterative Bronchiolitis diagnosed 1 year later and she switched to Tacrolimus. She was admitted to her local Hospital two and a half years later with right middle lobe consolidation. The patient commenced on amoxicillin and clarithromycin. Worsening renal indices, high Tacrolimus levels, hemolytic anemia & low Platelets were detected. HUS diagnosed & treated with plasmapheresis.

Conclusions

There are 21 cases of HUS following lung transplantation in the literature that may have been induced by high tacrolimus levels. Macrolides in patients taking Cyclosporin or Tacrolimus lead to high levels. Mechanism of action could be glomeruloconstrictor effect with reduced GFR increased production of Endothelin-1 and increased Platelet aggregation.

Everolimus with reduced calcineurin inhibitor in thoracic transplant recipients with renal dysfunction: a multicenter, randomized trial

BACKGROUND

The proliferation signal inhibitor everolimus offers the potential to reduce calcineurin inhibitor (CNI) exposure and alleviate CNI-related nephrotoxicity. Randomized trials in maintenance thoracic transplant patients are lacking.

METHODS

In a 12-month, open-labeled, multicenter study, maintenance thoracic transplant patients (glomerular filtration rate > or =20 mL/min/1.73m and <90 mL/min/1.73 m) >1 year posttransplant were randomized to continue their current CNI-based immunosuppression or start everolimus with predefined CNI exposure reduction.

RESULTS

Two hundred eighty-two patients were randomized (140 everolimus, 142 controls; 190 heart, 92 lung transplants). From baseline to month 12, mean cyclosporine and tacrolimus trough levels in the everolimus cohort decreased by 57% and 56%, respectively. The primary endpoint, mean change in measured glomerular filtration rate from baseline to month 12, was 4.6 mL/min with everolimus and -0.5 mL/min in controls (P<0.0001). Everolimus-treated heart and lung transplant patients in the lowest tertile for time posttransplant exhibited mean increases of 7.8 mL/min and 4.9 mL/min, respectively. Biopsy-proven treated acute rejection occurred in six everolimus and four control heart transplant patients (P=0.54). In total, 138 everolimus patients (98.6%) and 127 control patients (89.4%) experienced one or more adverse event (P=0.002). Serious adverse events occurred in 66 everolimus patients (46.8%) and 44 controls (31.0%) (P=0.02).

CONCLUSION

Introduction of everolimus with CNI reduction offers a significant improvement in renal function in maintenance heart and lung transplant recipients. The greatest benefit is observed in patients with a shorter time since transplantation.

Gastrointestinal and liver adverse effects of drugs used for treating IBD

Drugs used for treating inflammatory bowel disease are known to have a number of gastrointestinal and liver adverse effects. 5-ASA products are relatively safe and have few adverse events. In contrast sulfasalazine has side effects in 11-40% of treated patients including fatigue, nausea, abdominal pain and diarrhoea. Glucocorticoids can induce or propagate peptic ulcers and upper GI bleeding especially in combination with NSAIDs. Thioguanins may have severe gastrointestinal side effects including gastrointestinal complaints (in up to 12%), hepatotoxicity (up to 4%) and pancreatitis (1%). Nodular regenerative hyperplasia (NRH) is an important potential side effect of thiopurine therapy especially in men with Crohn's disease after ileocecal resection. NRH may ultimately lead to portal hypertension. A major concern of methotrexate therapy in IBD besides myelosuppression and pulmonary fibrosis is hepatotoxicity. 5mg of folic acid substitution per week potentially decreases gastrointestinal side effects by 80% without interfering with the efficacy of methotrexate. Besides renal dysfunction, tremor, hirsutism, hypertension and gum hyperplasia cyclosporine is known to have a number of gastrointestinal side effects that occur with less frequency such as diarrhoea (up to 8%) nausea and vomiting (up to 10%) and hepatotoxicity in 1-4%. Rare gastrointestinal adverse events are gastritis and peptic ulcers. Paying attention to these potential deleterious side effects is mandatory for physicians treating IBD patients.

Mycophenolate mofetil: safety and efficacy in the prophylaxis of acute kidney transplantation rejection

Mycophenolate mofetil (MMF), a prodrug of mycophenolic acid (MPA), is an inhibitor of inosine monophosphate dehydrogenase (IMPDH). It preferentially inhibits denovo pathway of guanosine nucleotide synthesis in T and B-lymphocytes and prevents their proliferation, thereby suppresses both cell mediated and humoral immune responses. Clinical trials in kidney transplant recipients have shown the efficacy of MMF in reducing the incidence and severity of acute rejection episodes. It also improves long term graft function as well as graft and patient survival in kidney transplant recipients. MMF is useful as a component of toxicity sparing regimens to reduce or avoid exposure of steroids or calcineurin inhibitor (CNI). Enteric-coated mycophenolate sodium (EC-MPS) can be used as an alternative immunosuppressive agent in kidney transplant recipients with efficacy and safety profile similar to MMF.

Twenty-year survivors of heart transplantation at Stanford University

Human heart transplantation started 40 years ago. Medical records of all cardiac transplants performed at Stanford were reviewed. A total of 1446 heart transplantations have been performed between January 1968 and December 2007 with an increase of 1-year survival from 43.1% to 90.2%. Sixty patients who were transplanted between 1968 and 1987 were identified who survived at least 20 years. Twenty-year survivors had a mean age at transplant of 29.4 +/- 13.6 years. Rejection-free and infection-free 1-year survivals were 14.3% and 18.8%, respectively. At their last follow-up, 86.7% of long-term survivors were treated for hypertension, 28.3% showed chronic renal dysfunction, 6.7% required hemodialysis, 10% were status postkidney transplantation, 13.3% were treated for diabetes mellitus, 36.7% had a history of malignancy and 43.3% had evidence of allograft vasculopathy. The half-life conditional on survival to 20 years was 28.1 years. Eleven patients received a second heart transplant after 11.9 +/- 8.0 years. The most common causes of death were allograft vasculopathy (56.3%) and nonlymphoid malignancy (25.0%). Twenty-year survival was achieved in 12.5% of patients transplanted before 1988. Although still associated with considerable morbidity, long-term survival is expected to occur at much higher rates in the future due to major advances in the field over the past decade.

Cardiac allograft vasculopathy and insulin resistance--hope for new therapeutic targets

Cardiac allograft vasculopathy (CAV) is a major cause of death in patients surviving more than 1 year after heart transplantation. An important cluster of CAV risk factors occurs as a consequence of insulin resistance and manifests as part of the metabolic syndrome. This article summarizes the pathologic features of CAV and reviews the contribution of the major components of insulin resistance in CAV development and progression. It focuses on the few studies that have analyzed the impact of the individual metabolic abnormalities and inflammation and on therapeutic strategies to minimize the clinical manifestation of insulin resistance after heart transplantation.

Cardiac allograft vasculopathy and insulin resistance--hope for new therapeutic targets

Cardiac allograft vasculopathy (CAV) is a major cause of death in patients surviving more than 1 year after heart transplantation. An important cluster of CAV risk factors occurs as a consequence of insulin resistance and manifests as part of the metabolic syndrome. This article summarizes the pathologic features of CAV and reviews the contribution of the major components of insulin resistance in CAV development and progression. It focuses on the few studies that have analyzed the impact of the individual metabolic abnormalities and inflammation and on therapeutic strategies to minimize the clinical manifestation of insulin resistance after heart transplantation.

Calcineurin inhibitors and rapamycin: cancer protection or promotion?

Since the introduction of cyclosporin A (CsA) in the early 1980s, the use of immunosuppressants has markedly increased. Already established drugs have proved effective in the treatment of a wide range of diseases outside transplantation medicine and new immunosuppressants have been developed for more specific indications such as psoriasis and atopic dermatitis. Patients in transplantation medicine as well as in dermatology have benefited significantly from systemic and topical application of both new and established drugs. But are these drugs without risks? Cancer-protecting effects have been reported for some of the available immunosuppressants. Conversely, other publications and the issue of a black box warning by the US Food and Drug Administration have increased concerns about cancer-promoting effects. Knowledge of the specific effects as well as adverse effects is paramount to ensure an application that is safe and beneficial for the patient. Here we review the mechanisms of action and therapeutic potential, and critically review recent literature with respect to possible carcinogenic side effects of systemic and topical CsA, tacrolimus, pimecrolimus and rapamycin.

Recommendations for the use of everolimus (Certican) in heart transplantation: results from the second German-Austrian Certican Consensus Conference

Everolimus (Certican; Novartis Pharma AG, Basel, Switzerland) represents the latest generation of proliferation signal inhibitors (PSIs). Everolimus is indicated for use as an immunosuppressive drug in renal and heart transplantation. This report reflects the recommendations of the second German-Austrian Certican Consensus Conference, held in January 2006, for the clinical use of everolimus.

Calcineurin inhibitor-free immunosuppression using everolimus (Certican) in maintenance heart transplant recipients: 6 months' follow-up

BACKGROUND

Everolimus is a proliferation signal-inhibitor recently introduced in heart transplant recipients. To date, little is known about calcineurin inhibitor (CNI)-free immunosuppression using everolimus. This study reports the results of CNI-free immunosuppression using everolimus.

METHODS

During a continuous 9-month period, 60 heart transplant recipients were enrolled. Reasons for switching to everolimus were side effects associated with prior CNI immunosuppression. All patients underwent standardized switching protocols and completed 6 months of follow-up. Blood was obtained for lipid status, renal function, routine controls, and levels of immunosuppressive agents. Echocardiography and a physical examination were performed on Days 0, 14, 28, and then every 3 months.

RESULTS

After switching to everolimus, most patients recovered from the side effects associated with CNIs. Renal function improved significantly after 6 months (creatinine, 2.1 +/- 0.6 vs 1.5 +/- 0.9 mg/dl, p = 0.001; creatinine clearance, 42.2 +/- 21.6 vs 61.8 +/- 23.4 ml/[min x 1.73 m2], p = 0.018). Arterial hypertension improved after 3 months and remained decreased during the observation period. Tremor, peripheral edema, hirsutism, and gingival hyperplasia markedly improved. Adverse events occurred in 8 patients (13.3%), including interstitial pneumonia (n = 2), skin disorders (n = 2), reactivated hepatitis B (n = 1), and fever of unknown origin (n = 3).

CONCLUSION

Preliminary data suggest that CNI-free immunosuppression using everolimus is safe, with excellent efficacy in maintenance heart transplant recipients. Arterial hypertension and renal function improved significantly. CNI-induced side effects such as tremor, peripheral edema, hirsutism, and gingival hyperplasia markedly improved in most patients.

Cardiac Transplantation Using Extended-Donor Criteria Organs for Systemic Amyloidosis Complicated by Heart Failure

BACKGROUND

Systemic amyloidosis complicated by heart failure is associated with high cardiovascular morbidity and mortality. Heart transplantation for patients with systemic amyloidosis is controversial due to recurrence of disease in the transplanted organ or progression of disease in other organs.

METHODS

All patients with systemic amyloidosis and heart failure referred for heart transplant evaluation from 1997 to 2004 were included in this retrospective cohort analysis. An interdisciplinary protocol for cardiac transplantation using extended-donor criteria organs, followed in 6 months by either high-dose chemotherapy and stem cell transplantation for patients with primary (AL) or by orthotopic liver transplantation for familial (ATTR) amyloidosis, was developed. Survival of the transplanted amyloid cohort was compared to survival of those amyloid patients not transplanted and to patients transplanted for other indications.

RESULTS

A total of 25 patients with systemic amyloidosis and heart failure were included in the study; 12 patients received heart transplants. Amyloid heart transplant recipients were more likely female (58% vs. 8%, P=0.02) and had lower serum creatinine (1.3+/-0.5 vs. 2.0+/-0.7 mg/dL, P=0.01) than nontransplanted amyloid patients. Survival at 1-year after heart transplant evaluation was higher among transplanted patients (75% vs. 23%) compared to patients not transplanted (P=0.001). Short-term survival posttransplant did not differ between transplanted amyloid patients and contemporaneous standard and extended-donor criteria heart transplant patients (P=0.65).

CONCLUSIONS

Cardiac transplantation for amyloid patients with extended-donor criteria organs followed by either stem cell or liver transplantation is associated with improved survival compared to patients not transplanted. Short- to intermediate-term survival is similar to patients receiving heart transplantation for other indications. This clinical management strategy provides cardiac amyloid patients a novel therapeutic option.