Current strategies and future trends in immunosuppression after heart transplantation. Curr Opin Organ Transplant. 2012;17:540-545. [PMID: 22941325 DOI: 10.1097/mot.0b013e328358000c]

Electroconductive cardiac patch based on bioactive PEDOT:PSS hydrogels

Engineering cardiac implants for treating myocardial infarction (MI) has advanced, but challenges persist in mimicking the structural properties and variability of cardiac tissues using traditional bioconstructs and conventional engineering methods. This study introduces a synthetic patch with a bioactive surface designed to swiftly restore functionality to the damaged myocardium. The patch combines a composite, soft, and conductive hydrogel-based on (3,4-ethylenedioxythiophene):polystyrene-sulfonate (PEDOT:PSS) and polyvinyl alcohol (PVA). This cardiac patch exhibits a reasonably high electrical conductivity (40 S/cm) and a stretchability up to 50% of its original length. Our findings reveal its resilience to 10% cyclic stretching at 1 Hz with no loss of conductivity over time. To mediate a strong cell-scaffold adhesion, we biofunctionalize the hydrogel with a N-cadherin mimic peptide, providing the cardiac patch with a bioactive surface. This modification promote increased adherence and proliferation of cardiac fibroblasts (CFbs) while effectively mitigating the formation of bacterial biofilm, particularly against Staphylococcus aureus, a common pathogen responsible for surgical site infections (SSIs). Our study demonstrates the successful development of a structurally validated cardiac patch possessing the desired mechanical, electrical, and biofunctional attributes for effective cardiac recovery. Consequently, this research holds significant promise in alleviating the burden imposed by myocardial infarctions.

Probiotics treatment ameliorated mycophenolic acid-induced colitis by enhancing intestinal barrier function and improving intestinal microbiota dysbiosis in mice

Background

Mycophenolic acid (MPA)-induced colitis was still a severe side effect and challenge faced by solid transplant recipients. We aimed to explore the function and mechanism of probiotics in the treatment of MPA-induced colitis.

Methods

In this study, 15 mice (C57BL/6) were randomly assigned into three groups: control (CNTL) group (n = 5), MPA group (n = 5) and the MPA + Probiotic group (n = 5). Bifid Triple Viable capsules, which were drugs for clinical use and consisted of Bifidobacterium longum, Lactobacillus acidophilus, and Enterococcus faecalis, were used in Probiotic group. Body weight change, stool scores, colon histopathology and morphology were used to evaluate the disease severity. The intestinal mucosal barrier function was assessed by measuring the expression level of secretory immunoglobulin A (sIgA), Zonula occludens-1 (ZO-1) and Occludin. Finally, 16S rDNA sequencing and bioinformatics analysis were performed on mice feces to compare the different intestinal microbial composition and diversity among three groups.

Results

Compared with the CNTL group, the mice in MPA group showed a significantly decreased body weight, increased stool scores, shortened colon length and severe colon inflammation. However, probiotics treated MPA mice reversed the disease severity, indicating that probiotics ameliorated MPA-induced colitis in mice. Mechanistically, probiotics improved the intestinal barrier function by up-regulating the expression of sIgA, ZO-1 and Occludin. Moreover, MPA-induced colitis led to intestinal microbiota dysbiosis, including the change of Firmicutes/Bacteroidetes ratio, α- and β-diversity. But probiotic treated group showed mild change in these microbial features. Additionally, we found that Clostridiales was the most significantly different microbiota flora in MPA group.

Conclusion

Probiotics treatment ameliorated MPA-induced colitis by enhancing intestinal barrier function and improving intestinal microbiota dysbiosis. Clostridiales might be the dominant functional intestinal microflora and serve as the potential therapy target in MPA-induced colitis.

Mycophenolic acid and cancer risk in solid organ transplant recipients: Systematic review and meta-analysis

AIM

Mycophenolic acid (MPA) is an immunosuppressive drug commonly used for prophylaxis of graft rejection in solid organ transplant recipients. The main concern with the prolonged use of immunosuppressive drugs is the risk of developing cancer. However, it remains unclear whether the immunosuppressive regimens containing MPA confer an increased degree of cancer risk. The present study aimed to determine the association between MPA exposure and the incidence of cancer in solid organ transplant recipients.

METHODS

A systematic search was performed on the PubMed, EMBASE and Cochrane Library databases. Relevant articles that had findings on the incidence (or event) of cancer in cohorts with and without MPA exposure were retrieved for data extraction. A meta-analysis was conducted by means of the random-effects model, and the relative risk (RR) and its 95% confidence interval (95% CI) were used as a summary effect measure.

RESULTS

A total of 39 studies were eligible for inclusion, with 32 studies that enabled meta-analysis. MPA exposure was significantly associated with a lower risk of cancer when compared to azathioprine exposure (RR = 0.66, 95% CI = 0.53-0.81, P < .001) or no exposure to any additional treatments (RR = 0.85, 95% CI = 0.73-0.99, P = .04). There was no significant difference in cancer risk for the comparison between MPA exposure and mammalian target of rapamycin (mTOR) inhibitor exposure (RR = 1.54, 95% CI = 0.96-2.46, P = .07).

CONCLUSIONS

MPA exposure was not associated with an increased risk of cancer and may even be associated with a lower risk of cancer when compared to azathioprine or no treatment.

Targeting glutamine metabolism as an effective means to promote allograft acceptance while inhibit tumor growth

Recently the role of metabolic signaling pathways has emerged as playing a critical role in dictating the outcome of T cell responses. The uptake and metabolism of the amino acid glutamine is essential for effector T cell activation. Since the growth and expansion of tumor cells relies on similar anabolic and metabolic requirements, we hypothesized that glutamine blockage might represent a promising strategy to promote allograft survival while inhibit tumor growth. 6-Diazo-5-oxo-L-norleucine (DON) was used as a glutamine antagonist. First, an in vitro study of T cell proliferation was performed to examine the ability of glutamine antagonism to inhibit T cell proliferation. Then we investigated whether DON could prolong allograft survival and inhibit tumor growth by using a fully MHC-mismatched mice full thickness skin transplantation model and a mice TC-1 tumor-bearing model. The proliferation study demonstrated that DON inhibited effector T cells proliferation in a dose-dependent manner. We found a marked prolonged graft median survival time and significant tumor inhibition for mice that received DON compared to those that received no treatment. These results highlight that targeting glutamine metabolism can promote allograft acceptance in a long tumor-free period.

Generation of bioartificial hearts using decellularized scaffolds and mixed cells

BACKGROUND

Patients with end-stage heart failure must receive treatment to recover cardiac function, and the current primary therapy, heart transplantation, is plagued by the limited supply of donor hearts. Bioengineered artificial hearts generated by seeding of cells on decellularized scaffolds have been suggested as an alternative source for transplantation. This study aimed to develop a tissue-engineered heart with lower immunogenicity and functional similarity to a physiological heart that can be used for heart transplantation.

MATERIALS AND METHODS

We used sodium dodecyl sulfate (SDS) to decellularize cardiac tissue to obtain a decellularized scaffold. Mesenchymal stem cells (MSCs) were isolated from rat bone marrow and identified by flow cytometric labeling of their surface markers. At the same time, the multi-directional differentiation of MSCs was analyzed. The MSCs, endothelial cells, and cardiomyocytes were allowed to adhere to the decellularized scaffold during perfusion, and the function of tissue-engineered heart was analyzed by immunohistochemistry and electrocardiogram.

RESULTS

MSCs, isolated from rats differentiated into cardiomyocytes, were seeded along with primary rat cardiomyocytes and endothelial cells onto decellularized rat heart scaffolds. We first confirmed the pluripotency of the MSCs, performed immunostaining against cardiac markers expressed by MSC-derived cardiomyocytes, and completed surface antigen profiling of MSC-derived endothelial cells. After cell seeding and culture, we analyzed the performance of the bioartificial heart by electrocardiography but found that the bioartificial heart exhibited abnormal electrical activity. The results indicated that the tissue-engineered heart lacked some cells necessary for the conduction of electrical current, causing deficient conduction function compared to the normal heart.

CONCLUSION

Our study suggests that MSCs derived from rats may be useful in the generation of a bioartificial heart, although technical challenges remain with regard to generating a fully functional bioartificial heart.

WITHDRAWN: Acute Cellular Rejection and Infection Rates in Alemtuzumab vs Traditional Induction Therapy Agents for Lung and Heart Transplantation: A Systematic Review and Meta-analysis

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Transplant Proc. 2018; 50 (10):3739-3747, https://doi.org/10.1016/j.transproceed.2018.08.018. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Acute Cellular Rejection and Infection Rates in Alemtuzumab vs Traditional Induction Therapy Agents for Lung and Heart Transplantation: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

Heart and lung transplantation is a high-risk procedure requiring intensive immunosuppressive therapy for preventing organ rejection. Alemtuzumab, a CD52-specific monoclonal antibody, is increasingly used for induction therapy compared with conventional agents. However, there has been no systematic review comparing its efficacy with traditional therapeutic drugs.

METHODS

PubMed and EMBASE were searched to October 1, 2017, for articles on alemtuzumab in cardiothoracic transplant surgery. Of the 433 studies retrieved, 8 were included in the final meta-analysis.

RESULTS

In lung transplantation, alemtuzumab use was associated with lower odds of acute cellular rejection compared with antithymocyte globulin (odds ratio [OR], 0.21; 95% CI, 0.11-0.40; P < .001), lower acute rejection rates (OR, 0.12; 95% CI, 0.03-0.55; P < .01), and infection rates (OR, 0.69; 95% CI, 0.35-1.36; P = .33) when compared with basiliximab. Multivariate meta-regression analysis found that mean age, male sex, single lung transplant, double lung transplant, cytomegalovirus or Epstein-Barr virus status, idiopathic pulmonary fibrosis, cystic fibrosis, and mean ischemic time did not significantly influence acute rejection outcomes. For heart transplantation, alemtuzumab use was associated with lower acute rejection rates when compared with tacrolimus (OR, 0.44; 95% CI, 0.30-0.66; P < .001).

CONCLUSIONS

Alemtuzumab use was associated with lower rejection rates when compared with conventional induction therapy agents (antithymocyte globulin, basiliximab, and tacrolimus) in heart and lung transplantation. However, this was based on observational studies. Randomized controlled trials are needed to verify its clinical use.

The Transcription Factor NFATc1 Supports the Rejection of Heterotopic Heart Allografts

The immune suppressants cyclosporin A (CsA) and tacrolimus (FK506) are used worldwide in transplantation medicine to suppress graft rejection. Both CsA and FK506 inhibit the phosphatase calcineurin (CN) whose activity controls the immune receptor-mediated activation of lymphocytes. Downstream targets of CN in lymphocytes are the nuclear factors of activated T cells (NFATs). We show here that the activity of NFATc1, the most prominent NFAT factor in activated lymphocytes supports the acute rejection of heterotopic heart allografts. While ablation of NFATc1 in T cells prevented graft rejection, ectopic expression of inducible NFATc1/αA isoform led to rejection of heart allografts in recipient mice. Acceptance of transplanted hearts in mice bearing NFATc1-deficient T cells was accompanied by a reduction in number and cytotoxicity of graft infiltrating cells. In CD8⁺ T cells, NFATc1 controls numerous intracellular signaling pathways that lead to the metabolic switch to aerobic glycolysis and the expression of numerous lymphokines, chemokines, and their receptors, including Cxcr3 that supports the rejection of allogeneic heart transplants. These findings favors NFATc1 as a molecular target for the development of new strategies to control the cytotoxicity of T cells upon organ transplantation.

Sleeve Gastrectomy and Left Ventricular Assist Device for Heart Transplant

BACKGROUND AND OBJECTIVES

Heart failure (HF) is a severe obesity-related comorbidity. Many patients with end-stage HF eventually require cardiac transplantation for long-term survival. These patients may be precluded from enrollment in heart transplant programs secondary to morbid obesity. We propose a pathway involving sleeve gastrectomy (SG) for patients with morbid obesity and HF to afford cardiac transplantation eligibility.

METHODS

Three patients with HF and morbid obesity underwent implantation of a left ventricular assist device (LVAD) and SG at an academic tertiary care institution in Washington, DC. This retrospective review from April 2012 through January 2017 examines the perioperative course of these 3 patients with regard to bariatric and cardiac indices, including ejection fraction (EF), HF classification, comorbid diseases, and percentages of total weight loss (%TWL) and excess weight loss (%EWL).

RESULTS

All three patients underwent LVAD placement as a bridge to transplant but were excluded from cardiac transplantation secondary to body mass index (BMI) and were referred for bariatric surgery. All have demonstrated considerable weight loss, with average decrease in BMI of 19 points, 39% TWL, and 81% EWL at a mean of 44 months after SG. Two patients have gone on to receive heart transplants, with near normalization of their EF.

CONCLUSION

LVAD and SG constitute a feasible pathway to cardiac transplantation in morbidly obese patients with end-stage HF. LVAD permits temporary cardiac support, whereas SG assists in efficacious weight loss. We explore SG as a durable weight loss option in patients with HF, with LVAD to improve eligibility for orthotopic cardiac transplantation.

Influence of tacrolimus metabolism rate on renal function after solid organ transplantation

The calcineurin inhibitor (CNI) tacrolimus (TAC) is an integral part of the immunosuppressive regimen after solid organ transplantation. Although TAC is very effective in prevention of acute rejection episodes, its highly variable pharmacokinetic and narrow therapeutic window require frequent monitoring of drug levels and dose adjustments. TAC can cause CNI nephrotoxicity even at low blood trough levels (4-6 ng/mL). Thus, other factors besides the TAC trough level might contribute to CNI-related kidney injury. Unfortunately, TAC pharmacokinetic is determined by a whole bunch of parameters. However, for daily clinical routine a simple application strategy is needed. To address this problem, we and others have evaluated a simple calculation method in which the TAC blood trough concentration (C) is divided by the daily dose (D). Fast TAC metabolism (C/D ratio < 1.05) was identified as a potential risk factor for an inferior kidney function after transplantation. In this regard, we recently showed a strong association between fast TAC metabolism and CNI nephrotoxicity as well as BKV infection. Therefore, the TAC C/D ratio may assist transplant clinicians in a simple way to individualize the immunosuppressive regimen.

Delayed Cytotoxic T Lymphocyte-Associated Protein 4-Immunoglobulin Treatment Reverses Ongoing Alloantibody Responses and Rescues Allografts From Acute Rejection

Antibody-mediated rejection has emerged as the leading cause of late graft loss in kidney transplant recipients, and inhibition of donor-specific antibody production should lead to improved transplant outcomes. The fusion protein cytotoxic T lymphocyte-associated protein 4-immunoglobulin (CTLA4-Ig) blocks T cell activation and consequently inhibits T-dependent B cell antibody production, and the current paradigm is that CTLA4-Ig is effective with naïve T cells and less so with activated or memory T cells. In this study, we used a mouse model of allosensitization to investigate the efficacy of continuous CTLA4-Ig treatment, initiated 7 or 14 days after sensitization, for inhibiting ongoing allospecific B cell responses. Delayed treatment with CTLA4-Ig collapsed the allospecific germinal center B cell response and inhibited alloantibody production. Using adoptively transferred T cell receptor transgenic T cells and a novel approach to track endogenous graft-specific T cells, we demonstrate that delayed CTLA4-Ig minimally inhibited graft-specific CD4(+) and T follicular helper responses. Remarkably, delaying CTLA4-Ig until day 6 after transplantation in a fully mismatched heart transplant model inhibited alloantibody production and prevented acute rejection, whereas transferred hyperimmune sera reversed the effects of delayed CTLA4-Ig. Collectively, our studies revealed the unexpected efficacy of CTLA4-Ig for inhibiting ongoing B cell responses even when the graft-specific T cell response was robustly established.

Comparing open gastrostomy tube to percutaneous endoscopic gastrostomy tube in heart transplant patients

Introduction

Impaired wound healing due to immunosuppression has led some surgeons to preferentially use open gastrostomy tube (OGT) over percutaneous gastrostomy tube (PEG) in heart transplant patients when long-term enteral access is deemed necessary.

Methods

The National Inpatient Sample (NIS) database (2005–2010) was queried for all heart transplant patients. Those receiving OGT were compared to those treated with PEG tube.

Results

There were 498 patients requiring long-term enteral access treated with a gastrostomy tube, with 424 (85.2%) receiving a PEG and 74 (14.8%) an OGT. The PEG cohort had higher Charlson comorbidity Index (4.1 vs. 2.0, p = 0.002) and a higher incidence of post-operative acute renal failure (31.5 vs. 12.7%, p = 0.001). Post-operative mortality was not different when comparing the two groups (13.8 vs. 6.1%, p = 0.06). On multivariate analysis, while both PEG (OR: 7.87, 95%C.I: 5.88–10.52, p < 0.001) and OGT (OR 5.87, 95%CI: 2.19–15.75, p < 0.001) were independently associated with mortality, PEG conferred a higher mortality risk.

Conclusions

This is the largest reported study to date comparing outcomes between PEG and OGT in heart transplant patients. PEG does not confer any advantage over OGT in this patient population with respect to morbidity, mortality, and length of stay.

•

OGT may result in less mortality than PEG in heart transplant patients.

•

Complications occur more frequently when heart transplant recipients receive PEG.

•

PEG in heart transplant recipients does not result in decreased LOS or total cost.

NFATc1 releases BCL6-dependent repression of CCR2 agonist expression in peritoneal macrophages from Saccharomyces cerevisiae infected mice

The link between the extensive usage of calcineurin (CN) inhibitors cyclosporin A and tacrolimus (FK506) in transplantation medicine and the increasing rate of opportunistic infections within this segment of patients is alarming. Currently, how peritoneal infections are favored by these drugs, which impair the activity of several signaling pathways including the Ca(++) /CN/NFAT, Ca(++) /CN/cofilin, Ca(++) /CN/BAD, and NF-κB networks, is unknown. Here, we show that Saccharomyces cerevisiae infection of peritoneal resident macrophages triggers the transient nuclear translocation of NFATc1β isoforms, resulting in a coordinated, CN-dependent induction of the Ccl2, Ccl7, and Ccl12 genes, all encoding CCR2 agonists. CN inhibitors block the CCR2-dependent recruitment of inflammatory monocytes (IM) to the peritoneal cavities of S. cerevisiae infected mice. In myeloid cells, NFATc1/β proteins represent the most prominent NFATc1 isoforms. NFATc1/β ablation leads to a decrease of CCR2 chemokines, impaired mobilization of IMs, and delayed clearance of infection. We show that, upon binding to a composite NFAT/BCL6 regulatory element within the Ccl2 promoter, NFATc1/β proteins release the BCL6-dependent repression of Ccl2 gene in macrophages. These findings suggest a novel CN-dependent cross-talk between NFAT and BCL6 transcription factors, which may affect the outcome of opportunistic fungal infections in immunocompromised patients.

How do kinases contribute to tonicity-dependent regulation of the transcription factor NFAT5?

NFAT5 plays a critical role in maintaining the renal functions. Its dis-regulation in the kidney leads to or is associated with certain renal diseases or disorders, most notably the urinary concentration defect. Hypertonicity, which the kidney medulla is normally exposed to, activates NFAT5 through phosphorylation of a signaling molecule or NFAT5 itself. Hypotonicity inhibits NFAT5 through a similar mechanism. More than a dozen of protein and lipid kinases have been identified to contribute to tonicity-dependent regulation of NFAT5. Hypertonicity activates NFAT5 by increasing its nuclear localization and transactivating activity in the early phase and protein abundance in the late phase. The known mechanism for inhibition of NFAT5 by hypotonicity is a decrease of nuclear NFAT5. The present article reviews the effect of each kinase on NFAT5 nuclear localization, transactivation and protein abundance, and the relationship among these kinases, if known. Cyclosporine A and tacrolimus suppress immune reactions by inhibiting the phosphatase calcineurin-dependent activation of NFAT1. It is hoped that this review would stimulate the interest to seek explanations from the NFAT5 regulatory pathways for certain clinical presentations and to explore novel therapeutic approaches based on the pathways. On the basic science front, this review raises two interesting questions. The first one is how these kinases can specifically signal to NFAT5 in the context of hypertonicity or hypotonicity, because they also regulate other cellular activities and even opposite activities in some cases. The second one is why these many kinases, some of which might have redundant functions, are needed to regulate NFAT5 activity. This review reiterates the concept of signaling through cooperation. Cells need these kinases working in a coordinated way to provide the signaling specificity that is lacking in the individual one. Redundancy in regulation of NFAT5 is a critical strategy for cells to maintain robustness against hypertonic or hypotonic stress.

Human induced pluripotent stem cell-derived cardiac tissue on a thin collagen membrane with natural microstructures

We present a new strategy to produce a thin collagen membrane from porcine tendons and engineered cardiac tissues using hiPSC-derived cardiomyocytes.

Mycophenolate mofetil therapy for severe immune thrombocytopenia

Severe immune thrombocytopenia purpura (ITP) presents a clinical challenge. Second-line treatment options are variable without a precise protocol. We present 46 severe ITP patients treated with mycophenolate mofetil (MMF), retrospectively identified from three London teaching hospitals. Data was collected on patient demographics, co-morbidities and previous treatment strategies. Our key interest was whether there was a sustained response in platelet count to MMF. Patients included 27 males and 19 females whose ages ranged from 19 to 93 years old (median 52·5 years). Twenty-nine had primary ITP and 17 had secondary ITP, a third of whom had viral-associated disease. The standard dose of MMF was 1 g/day. Twenty-four patients (52%) responded with 15 (33%) achieving a complete response. No active viral-associated ITP patients demonstrated a response to MMF, although numbers were small (n = 4). We were not able to demonstrate a difference between responders and non-responders based on gender, age, previous therapies or time since diagnosis of ITP. Three of four previously splenectomized patients responded, two achieving complete response. We conclude that MMF is a useful steroid-sparing immunosuppressant to be considered in the second-line or later treatment of ITP.

Triple immunosuppressive therapy in steroid-resistant nephrotic syndrome children with tacrolimus resistance or tacrolimus sensitivity but frequently relapsing

AIM

The treatment strategy for steroid-resistant nephrotic syndrome remains uncertain at present, especially in those with calcineurin inhibitor resistance or intolerance. To date, few studies have been published using multiple combination therapy of immunosuppressive reagents for children with calcineurin inhibitor-resistant or -intolerant nephrotic syndrome.

METHODS

Eighteen consecutive children with steroid- and tacrolimus (TAC)-resistant (n = 10) or TAC-sensitive but frequent relapsing nephrotic syndrome (n = 8) were randomly recruited in the present study. All of them received further triple-combination therapy by cyclophosphamide (CTX, n = 6), mycophenolate mofetil (MMF, n = 5) or leflunomide (LEF, n = 7). Their clinical data were collected and efficacy of triple-combination therapy was evaluated.

RESULTS

Compared with previous double-combination therapy of prednisone (Pre) and TAC, the short-term remission rate in all 18 patients was significantly improved after the triple-combination therapy, while the frequent relapse rate in the following 12 months was also significantly decreased. Among three different subgroups with CTX, MMF or LEF therapy, no significant difference was found in short-term remission rate and the relapse rate within 1 year follow up by Kaplan-Meier plot.

CONCLUSION

Triple-combination therapy with Pre + TAC + CTX/MMF/LEF is effective for short-term response and 1 year remission, without significant additional side-effects seen in children with steroid-resistant and tacrolimus-resistant or tacrolimus-sensitive but frequently relapsing nephrotic syndrome. Further study for evaluating long-term efficacy and safety of triple-combination therapy with Pre + TAC + CTX/MMF/LEF would be necessary for these patients.

Dual-source cardiac computed tomography angiography (CCTA) in the follow-up of cardiac transplant: comparison of image quality and radiation dose using three different imaging protocols

OBJECTIVES

To prospectively evaluate image quality (IQ) and radiation dose of dual-source cardiac computed tomography (CCTA) using different imaging protocols.

METHODS

CCTA was performed in 150 patients using the retrospective ECG-gated spiral technique (rECG) the prospective ECG-gated technique (pECG), or the prospective ECG-gated technique with systolic imaging and automated tube voltage selection (pECGsys). IQ was rated using a 16-segment coronary artery model. Techniques were compared for overall IQ, IQ of the large and the small coronary artery segments. Effective dose was used for comparison of radiation dose.

RESULTS

Overall IQ and IQ of the large segments showed no differences between the groups. IQ analysis of the small segments showed lowered IQ in pECGsys compared to rECG (p = 0.02), but not to pECG (p = 0.6). Effective dose did not differ significantly between rECG and pECG (p = 0.13), but was significantly lower for pECGsys (p < 0.001 vs. rECG and pECG).

CONCLUSION

Radiation dose of dual-source CCTA in heart transplant recipients is significantly reduced by using prospective systolic scanning and automated tube voltage selection, while overall IQ and IQ of the large coronary segments are maintained. IQ appears to be lower compared to retrospective techniques with regard to small coronary segments.

KEY POINTS

• Cardiac computed tomography angiography is useful for cardiac allograft vasculopathy assessment. • Despite elevated heart rate, dose reduction in cardiac computed tomography is possible. • Prospective systolic gating and automated tube voltage selection enable 50 % dose reduction.

How to mend a broken heart: adult and induced pluripotent stem cell therapy for heart repair and regeneration

The recently developed ability to differentiate primary adult stem cells and induced pluripotent stem cells (iPSCs) into cardiomyocytes is providing unprecedented opportunities to produce an unlimited supply of cardiomyocytes for use in patients with heart disease. Here, we examine the evidence for the preclinical use of such cells for successful heart regeneration. We also describe advances in the identification of new cardiac molecular and cellular targets to induce proliferation of cardiomyocytes for heart regeneration. Such new advances are paving the way for a new innovative drug development process for the treatment of heart disease.

Heart and lung transplantation

PURPOSE OF REVIEW

Every year, thousands of heart and lung transplants are performed worldwide. As experience and clinical acumen advance, both fields are continually evolving. This review elucidates and describes many of the recent changes in practice and future directions of heart and lung transplantation. Preoperative, intraoperative and postoperative developments are presented with supporting evidence in these continually evolving fields.

RECENT FINDINGS

The field of heart transplantation is continually adapting to the growing use of mechanical circulatory support devices as bridge to transplant and for postoperative support. Recent modifications in surgical technique have contributed to improved outcomes.Lung transplantation advancements include the increasing use of extracorporeal membrane oxygenation during the perioperative period. Lobar transplantation and ex-vivo lung perfusion techniques may aid in providing successful lung grafts to those with potentially long wait list times.Rates of rejection continue to decline in both fields as immunosuppression regimens are improved and modified.

SUMMARY

This review investigates and summarizes the recent changes and advancements in heart and lung transplantation. Mechanical circulatory support and extracorporeal membrane oxygenation are increasingly used in the perioperative setting, and continuing research will evaluate their safety profiles. Optimizing and tailoring immunosuppression regimens for transplant recipients continue to be the subject of ongoing investigation.

The risk of cholelithiasis in patients after heart transplantation

INTRODUCTION

Extended immunosuppressive treatment in patients after heart transplantation modifies etiopathogenesis and occurrence of many diseases in this population. The aim of the present study was to evaluate the frequency and to define risk factors for cholelithiasis after heart transplantation (HTX).

MATERIAL AND METHODS

The study population consisted of 176 subjects. Of them, 24 patients (group A) presented with symptomatic cholelithiasis. Another group of 24 patients without cholelithiasis (group B) served as controls. Both groups were similar with respect to age, gender and follow-up after the transplant. Clinical interview, surgical and hospitalization data were collected from medical records.

RESULTS

The groups did not differ in demographic features. There were statistical differences (p < 0.05) between group A and B in rejection reaction, doses of immunosuppressive drugs, type 2 diabetes, serum lipid disorders and acute rejection episodes. These events were caused by modification of treatment, especially the immunosuppressive regimen. Group A consisted of 75% men and 25% women. The frequency of symptomatic cholelithiasis was 11.7% in men and 27.3% in women, on average 19.5%. Mean time to cholelithiasis following HTX was 37.9 ±4.9 (Me = 41.5) months, 27.7 ±8.2 (Me = 30.0) months in women and 41.3 ±5.9 (Me = 41.5) months in men. The female to male ratio was 2.3: 1.

CONCLUSIONS

Cholelithiasis following HTX was significantly more frequent as compared with the non-transplant population. Patients with cholelithiasis required more aggressive immunosuppression because of more frequent episodes of acute transplant rejection. Patients with cholelithiasis significantly more frequently showed increased glycemia and blood lipids, which could be the side effect of intensive immunosuppressive therapy.