Myocardial Flow Assessment After Heart Transplantation Using Dynamic Cadmium-Zinc-Telluride Single-Photon Emission Computed Tomography With 201Tl and 99mTc Tracers and Validated by 13N-NH3 Positron Emission Tomography.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is an obliterative and diffuse form of vasculopathy and is the most common cause of long-term cardiovascular mortality in heart transplant patients. This study aimed to investigate the diagnostic performance of 99mTc and 201Tl tracers in the assessment of CAV using cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) for myocardial blood flow (MBF) and myocardial flow reserve (MFR) quantification, which was further validated using 13 N-NH3 positron emission tomography (PET). METHODS: Thirty-eight patients with prior heart transplantation who underwent CZT SPECT and 13 N-NH3 PET dynamic scans were included in this study. CZT SPECT with 99mTc-sestamibi was used in the first 19 patients and 201Tl-chloride for the remaining patients. To determine the diagnostic accuracy of angiographically defined moderate-to-severe CAV, the analysis included patients who underwent angiographic examinations within 1 year of their second scan. RESULTS: There were no significant differences in the patient characteristics between the 201Tl and 99mTc tracer groups. Both 201Tl and 99mTc CZT SPECT-derived stress MBF and MFR values globally and in 3 coronary territories showed good correlations with 13 N-NH3 PET. The 201Tl and 99mTc cohorts did not differ significantly in the correlation coefficients of CZT SPECT versus PET for MBF and MFR, except for stress MBF (201Tl:0.95 versus 99mTc:0.80, P=0.03). 201Tl and 99mTc CZT SPECT were satisfactory for detecting PET MFR <2.0 (201Tl area under the curve, 0.92 [0.71-0.99], 99mTc area under the curve, 0.87 [0.64-0.97]) and angiographically defined moderate-to-severe CAV, and CZT SPECT results were comparable to that of 13 N-NH3 PET (CZT area under the curve, 0.90 [0.70-0.99], PET area under the curve, 0.86 [0.64-0.97]). CONCLUSIONS: This small study suggests that CZT SPECT using 201Tl and 99mTc tracers showed comparable MBF and MFR, and the results correlated well with those of 13 N-NH3 PET. Hence, CZT SPECT with 201Tl or 99mTc tracers can be used to detect moderate-to-severe CAV in patients with prior heart transplantation. However, validation using larger studies is warranted.

Effective naked plasmid DNA delivery into stem cells by microextrusion-based transient-transfection system for in situ cardiac repair.

BACKGROUND AIMS: Combining the use of transfection reagents and physical methods can markedly improve the efficiency of gene delivery; however, such methods often cause cell damage. Additionally, naked plasmids without any vector or physical stimulation are difficult to deliver into stem cells. In this study, we demonstrate a simple and rapid method to simultaneously facilitate efficient in situ naked gene delivery and form a bioactive hydrogel scaffold. METHODS: Transfecting naked GATA binding protein 4 (GATA4) plasmids into human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) by co-extruding naked plasmids and hUC-MSCs with a biomimetic and negatively charged water-based biodegradable thermo-responsive polyurethane (PU) hydrogel through a microextrusion-based transient-transfection system can upregulate the other cardiac marker genes. RESULTS: The PU hydrogels with optimized physicochemical properties (such as hard-soft segment composition, size, hardness and thermal gelation) induced GATA4-transfected hUC-MSCs to express the cardiac marker proteins and then differentiated into cardiomyocyte-like cells in 15 days. We further demonstrated that GATA4-transfected hUC-MSCs in PU hydrogel were capable of in situ revival of heart function in zebrafish in 30 days. CONCLUSIONS: Our results suggest that hUC-MSCs and naked plasmids encapsulated in PU hydrogels might represent a new strategy for in situ tissue therapy using the microextrusion-based transient-transfection system described here. This transfection system is simple, effective and safer than conventional technologies.

2019 Focused Update of the Guidelines of the Taiwan Society of Cardiology for the Diagnosis and Treatment of Heart Failure.

Heart failure is a growing epidemic, especially in Taiwan because of the aging population. The 2016 Taiwan Society of Cardiology - Heart Failure with reduced Ejection Fraction (TSOC-HFrEF) registry showed that the guideline-recommended therapies were prescribed suboptimally both at the time of hospital discharge and during follow-up. We, therefore, conducted this 2019 focused update of the guidelines of the Taiwan Society of Cardiology for the diagnosis and treatment of heart failure to reinforce the importance of new diagnostic and therapeutic modalities of heart failure. The 2019 focused update discusses new diagnostic criteria, pharmacotherapy, non-pharmacological management, and certain co-morbidities of heart failure. Angiotensin receptor neprilysin inhibitor and If channel inhibitor is introduced as new and recommended medical therapies. Latest criteria of cardiac resynchronization therapy, implantable cardioverter-defibrillator, heart transplantation, and ventricular assist device therapy are reviewed in the non-pharmacological management chapter. Co-morbidities in heart failure are discussed including chronic kidney disease, diabetes, chronic obstructive pulmonary disease, and sleep-disordered breathing. We also explain the adequate use of oxygen therapy and non-invasive ventilation in heart failure management. A particular chapter for chemotherapy-induced cardiac toxicity is incorporated in the focused update to emphasize the importance of its recognition and management. Lastly, implications from the TSOC-HFrEF registry and post-acute care of heart failure are discussed to highlight the importance of guideline-directed medical therapy and the benefits of multidisciplinary disease management programs. With guideline recommendations, we hope that the management of heart failure can be improved in our society.

CXCR4 Antagonist Reduced the Incidence of Acute Rejection and Controlled Cardiac Allograft Vasculopathy in a Swine Heart Transplant Model Receiving a Mycophenolate-based Immunosuppressive Regimen.

BACKGROUND: CXC motif chemokine receptor 4 (CXCR4) blockade is pursued as an alternative to mesenchymal stem cell treatment in transplantation based on our previous report that burixafor, through CXCR4 antagonism, mobilizes immunomodulatory mesenchymal stem cells. Here, we explored the efficacy of combining mycophenolate mofetil (MMF)-based immunosuppressants with repetitive burixafor administration. METHODS: Swine heterotopic cardiac allograft recipients received MMF and corticosteroids (control, n = 10) combined with burixafor as a 2-dose (burixafor2D, n = 7) or 2-dose plus booster injections (burixafor2D + B, n = 5) regimen. The efficacy endpoints were graft survival, freedom from first acute rejection, and the severity of intimal hyperplasia. Each specimen was sacrificed either at its first graft arrest or after 150 days. RESULTS: After 150 days, all specimens in the control group had died, but 28.5% of the burixafor2D group survived, and 60% of the burixafor2D + B group survived (P = 0.0088). Although the control group demonstrated acute rejection at a median of 33.5 days, the burixafor2D + B group survived without acute rejection for a median of 136 days (P = 0.0209). Burixafor administration significantly attenuated the incidence rate of acute rejection (P = 0.002) and the severity of intimal hyperplasia (P = 0.0097) at end point relative to the controls. These findings were associated with reduced cell infiltrates in the allografts, and modulation of C-reactive protein profiles in the circulation. CONCLUSIONS: The augmentation of conventional MMF plus corticosteroids with a CXCR4 antagonist is potentially effective in improving outcomes after heart transplantation in minipigs. Future studies are warranted into optimizing the therapeutic regimens for humans.

Fulminant primary cardiac lymphoma with sudden cardiac death: A case report and brief review.

Primary cardiac lymphoma (PCL) is very rare, with the variable clinical manifestations potentially leading to a delayed diagnosis. PCL is usually detected incidentally through image studies, whereas the diagnosis can be confirmed via analysis of pericardial effusion, endomyocardial biopsy tissue, or surgical specimens. Although no standard therapy has been established for PCL, without treatment, the prognosis is grave, with the estimated overall survival being approximately 1 year. We report a difficult diagnosis and complicated case of fulminant PCL, which is the first comprehensively reported case of PCL with secondary hemophagocytosis. A man presented with progressive dyspnea for 3 weeks, and then sudden cardiac death with ventricular fibrillation occurred. After resuscitation, echocardiography revealed a thickened left ventricular wall and severe mitral regurgitation, and computed tomography showed a right atrial mass with diffuse myocardial lesions. PCL was confirmed through a pathological analysis of specimens collected during mitral valvuloplasty, which also implied extensive myocardial involvement. Bone marrow biopsy demonstrated no evidence of lymphoma involvement, but secondary hemophagocytosis was noted. Despite aggressive chemotherapy, the patient died of sepsis with multiorgan failure 26 days after the operation.

CXCR4 Antagonist TG-0054 Mobilizes Mesenchymal Stem Cells, Attenuates Inflammation, and Preserves Cardiac Systolic Function in a Porcine Model of Myocardial Infarction.

Interaction between chemokine stromal cell-derived factor 1 and the CXC chemokine receptor 4 (CXCR4) governs the sequestration and mobilization of bone marrow stem cells. We investigated the therapeutic potential of TG-0054, a novel CXCR4 antagonist, in attenuating cardiac dysfunction after myocardial infarction (MI). In miniature pigs (minipigs), TG-0054 mobilized CD34(+)CXCR4(+), CD133(+)CXCR4(+), and CD271(+)CXCR4(+) cells into peripheral circulation. After isolation and expansion, TG-0054-mobilized CD271(+) cells were proved to be mesenchymal stem cells (designated CD271-MSCs) since they had trilineage differentiation potential, surface markers of MSCs, and immunosuppressive effects on allogeneic lymphocyte proliferation. MI was induced in 22 minipigs using balloon occlusion of the left anterior descending coronary artery, followed by intravenous injections of 2.85 mg/kg of TG-0054 or saline at 3 days and 7 days post-MI. Serial MRI analyses revealed that TG-0054 treatment prevented left ventricular (LV) dysfunction at 12 weeks after MI (change of LV ejection fraction from baseline, -1.0 ± 6.2% in the TG-0054 group versus -7.9 ± 5.8% in the controls). The preserved cardiac function was accompanied by a significant decrease in the myocardial expression of TNF-α, IL-1ß, and IL-6 at 7 days post-MI. Moreover, the plasma levels of TNF-α, IL-1ß, and IL-6 were persistently suppressed by the TG-0054 treatment. Infusion of TG-0054-mobilized CD271-MSCs reduced both myocardial and plasma cytokine levels in a pattern, which is temporally correlated with TG-0054 treatment. This study demonstrated that TG-0054 improves the impaired LV contractility following MI, at least in part, by mobilizing MSCs to attenuate the postinfarction inflammation. This insight may facilitate exploring novel stem cell-based therapy for treating post-MI heart failure.

Prostaglandin E2 potentiates mesenchymal stem cell-induced IL-10+IFN-γ+CD4+ regulatory T cells to control transplant arteriosclerosis.

Mesenchymal stem cells (MSCs) are known for their immunomodulatory functions. We previously demonstrated that bone marrow-derived MSCs effectively control transplant arteriosclerosis (TA) by enhancing IL-10(+) and IFN-γ(+) cells. The objective of this study is to elucidate the mechanism by which MSCs induce IL-10(+)IFN-γ(+)CD4(+) regulatory T type 1 (T(R)1)-like cells. In an MLR system using porcine PBMCs, MSC-induced IL-10(+)IFN-γ(+)CD4(+) cells, which confer resistance to allogeneic proliferation in an IL-10-dependent manner, resemble T(R)1-like cells. Both cyclooxygenase-derived PGE(2) and IDO help to induce T(R)1-like cells by MSCs. MSCs constitutively secrete PGE(2), which is augmented in allogeneic reactions. However, T(R)1-like cells were deficient in PGE(2) and 4-fold less potent than were MSCs in suppressing MLR. PGE(2) mimetic supplements can enhance the immunosuppressive potency of T(R)1-like cells. In a porcine model of allogeneic femoral arterial transplantation, MSC-induced T(R)1-like cells combined with PGE(2), but not either alone, significantly reduced TA at the end of 6 wk (percentage of luminal area stenosis: T(R)1-like cells + PGE(2): 11 ± 10%; PGE(2) alone: 93 ± 8.7%; T(R)1-like cells alone: 88 ± 2.4% versus untreated 94 ± 0.9%, p < 0.001). These findings indicate that PGE(2) helps MSC-induced IL-10(+)IFN-γ(+)CD4(+) T(R)1-like cells inhibit TA. PGE(2) combined with MSC-induced T(R)1-like cells represents a new approach for achieving immune tolerance.

Autologous mesenchymal stem cells prevent transplant arteriosclerosis by enhancing local expression of interleukin-10, interferon-γ, and indoleamine 2,3-dioxygenase.

Transplant arteriosclerosis (TA) remains the major limitation of long-term graft survival in heart transplantation despite the advances in immunosuppressants. Mesenchymal stem cells (MSCs) have been demonstrated to suppress allogeneic immune responses by numerous in vitro studies. However, the immunomodulatory effects of MSCs in vivo are controversial and the underlying molecular mechanisms are not conclusive. In this study, we investigated the therapeutic potential of autologous bone marrow-derived MSCs on TA in a porcine model of femoral artery transplantation. MSCs or saline were injected into the soft tissue surrounding the arterial grafts immediately postanastomosis. Four weeks after transplantation, neointimal formation increased significantly in untreated allografts compared with the MSC-treated grafts as assessed by intravascular ultrasound (maximum luminal area stenosis: 40 ± 12% vs. 18 ± 6%, p < 0.001). Grafts harvested at 4 weeks showed dense perivascular lymphocyte infiltration accompanied by significant intimal hyperplasia in the untreated but not in the MSC-treated allografts. Serial angiographic examination showed that all of the untreated allografts became occluded at the 8th week whereas the majority of the MSC-treated grafts remained patent at the 12th week posttransplantation (n = 12 each group, p < 0.001). Quantitative PCR analysis revealed that Foxp3 expression was comparable between the untreated and the MSC-treated groups. However, expression of interleukin-10 (IL-10), interferon-γ (IFN-γ), and indoleamine 2,3-dioxygenase (IDO) was increased significantly in the MSC-treated allografts compared with that in the allograft controls (p = 0.021 for IL-10, p = 0.003 for IFN-γ, and p = 0.008 for IDO). In conclusion, local delivery of autologous MSCs alleviates TA by inducing allograft tolerance via enhanced expression of IL-10, IFN-γ, and IDO but not Foxp3-positive cells in the vessel wall. These results suggest that MSCs induce immune tolerance by activating the type 1 regulatory T-like cells.

Continuous intravenous infusion of prostaglandin E1 improves myocardial perfusion reserve in patients with ischemic heart disease assessed by positron emission tomography: a pilot study.

OBJECTIVE: Recent investigation has demonstrated that prostaglandin E(1) (PGE(1)) therapy increased capillary density in explanted hearts. Dynamic (13)N-ammonia positron emission tomography (PET) is reliable for non-invasive measurement of myocardial blood flow and myocardial perfusion reserve (MPR). The aim of this study was to investigate the effects of PGE(1) therapy during 4 weeks on reduction of myocardial perfusion abnormalities and increase of MPR in the patients with ischemic heart disease. METHODS: In this double-blind, placebo-controlled trial, we randomly assigned 11 patients who had symptomatic heart failure and documented myocardial ischemia to 4 weeks intravenous infusion of PGE(1) (2.5 ng/kg/min; 8 patients, age 60 ± 13 years) or saline (3 patients, age 57 ± 13 years). Dynamic (13)N-ammonia PET scans at rest and during adenosine stress were obtained at baseline and 12 weeks after treatment completion. Quantitative size/severity of perfusion defects and MPR change from baseline to follow-up PET were determined using a 17-segment model. RESULTS: Compared with the control group, baseline MPR in the PGE(1) group was significantly lower (1.96 ± 0.78 vs. 2.71 ± 0.73; P < 0.001). MPR significantly improved 12 weeks after completion of PGE(1) infusion (1.96 ± 0.78 to 2.16 ± 0.77; P < 0.001). In contrast, MPR declined significantly in the placebo group (2.71 ± 0.73 to 2.01 ± 0.58, P < 0.001). CONCLUSION: Four weeks of PGE(1) infusion sustained MPR improvement in patients with ischemic heart disease. This may be an attractive therapeutic approach for no-option patients with severe ischemic cardiomyopathy.

PET assessment of myocardial perfusion reserve inversely correlates with intravascular ultrasound findings in angiographically normal cardiac transplant recipients.

UNLABELLED: Cardiac allograft vasculopathy (CAV) is the major determinant of long-term survival after heart transplantation. We aimed to evaluate the efficacy of PET as a noninvasive way to assess the early stages of CAV. METHODS: Twenty-seven consecutive patients (20 men and 7 women; mean age +/- SD, 46 +/- 12 y) who had normal results on coronary angiography and normal left ventricular systolic function (ejection fraction >or= 60%) were enrolled at 2.5 +/- 2.1 y after transplantation. Myocardial blood flow (MBF) was assessed using dynamic (13)N-ammonia PET at rest and during adenosine-induced hyperemia, and myocardial perfusion reserve (MPR) was calculated as the ratio of hyperemic MBF to resting MBF. Regional (13)N-ammonia PET was assessed using a 5-point scoring system. The intravascular ultrasound (IVUS) measurements for the extent of intimal hyperplasia, including plaque volume index (calculated as [total plaque volume/total vessel volume] x 100%) and maximum area of stenosis, were compared with MPR by linear regression analysis. RESULTS: In 27 angiographically normal cardiac transplant recipients, MBF at rest and during adenosine stress and MPR of the left anterior descending artery distribution correlated strongly with the other 2 coronary artery distribution territories (r >or= 0.97, P < 0.0001). Summed stress score and summed difference score showed a moderate inverse correlation with MPR (r = -0.41 and -0.49, respectively; P < 0.05) but not with IVUS measurements. MPR correlated inversely with plaque volume index (r = -0.40, P < 0.05) but not with maximal luminal stenosis as assessed by IVUS. In addition, MPR and IVUS measurements gradually inversely changed after heart transplantation (all P < 0.05). CONCLUSION: This study confirms that CAV is a progressive process, diffusely involving the epicardial and microvascular coronary system. Plaque burden as determined by IVUS agrees well with MPR as assessed by PET in recipients with normal coronary angiography results. This finding suggests that dynamic (13)N-ammonia PET is clinically feasible for the early detection of CAV and can be used as a reliable marker of disease progression.

Simultaneous heart and kidney transplantation from a single donor.

OBJECTIVE: There are no guidelines to establish the indications and contraindications for a simultaneous heart and kidney transplantation. We report our single-institutional experience with simultaneous heart and kidney transplantation. METHODS: Retrospective chart review. RESULTS: Between 1995 and 2006, 13 patients with co-existing end-stage heart and renal failure underwent simultaneous heart and kidney transplantation at the authors' hospital. Heart failure was secondary to dilated cardiomyopathy in five patients, ischemic cardiomyopathy in three, cardiac allograft vasculopathy in two, and congenital heart disease, cardiac allograft failure, and acute myocarditis each in one. Renal failure was secondary to glomerulonephritis in six patients, heart failure in two, cyclosporine nephropathy in three, hypertension in one, and systemic lupus erythematosus in one. Eight patients were in UNOS status IA and five patients in UNOS status II before transplantation. The 30-day mortality rate and in-hospital mortality rate were 15% and 38%. Of eight patients in UNOS status IA, seven patients have lived beyond 30 days and three (38%) beyond 1 year. Of five patients in UNOS status II, four patients have lived beyond 30 days and four (80%) beyond 1 year. Patients in UNOS status IA had high rates of previous cardiac surgery, cardiac allograft rejection, and major renal allograft complications. CONCLUSIONS: Although simultaneous heart and kidney transplantation continues to be a viable option for patients with co-existing end-stage heart and renal failure, the results do not match those of isolated heart transplantation. The clinical outcomes were not satisfactory in UNOS status IA patients with previous cardiac surgery.

Homocysteine inhibits arterial endothelial cell growth through transcriptional downregulation of fibroblast growth factor-2 involving G protein and DNA methylation.

Homocysteine (Hcy) contributes to atherogenesis and angiostasis by altering the phenotype of arterial endothelial cells (ECs). The present study was aimed at elucidating potential mechanisms by which Hcy can slow EC proliferation and induce EC apoptosis, thereby disrupting endothelial integrity. Given the strong mitogenic and antiapoptotic properties of fibroblast growth factor (FGF)2, we examined whether Hcy can modulate its expression. In cultured human coronary and bovine aortic ECs, Hcy exerted time- and concentration-dependent (0 to 500 micromol/L) reduction of the mRNA and protein levels of FGF2, whereas vascular endothelial growth factor expression was not affected until Hcy reached a proapoptotic 500 micromol/L. By testing a panel of signal transduction inhibitors, we found that the Hcy-induced downregulation of FGF2 was specifically attenuated by pertussis toxin, an inhibitor of Gi protein signaling. Hcy induced cell cycle arrest at the G(1)/S transition and increased TUNEL-positive apoptotic cells in a graded manner. These effects were effectively counteracted by exogenous FGF2. Reporter gene assays showed that Hcy downregulated FGF2 by transcriptional repression of the gene promoter encompassed in a CpG dinucleotide-rich island. This region was heavily methylated at the cytosine residues by Hcy despite decreased methylation potential (S-adenosylmethionine to S-adenosylhomocysteine ratio). Normal levels of FGF2 transcription were restored to ECs simultaneously exposed to Hcy and 5-aza-deoxycytidine. We conclude that homocysteine disrupts the growth and survival of ECs through a G protein-mediated pathway associated with altered promoter DNA methylation and the transcriptional repression of FGF2.

Value of circulating adhesion molecules in assessing cardiac allograft vasculopathy.

Circulating adhesion molecules have been implicated in the development of spontaneous and transplant coronary artery disease. We analyzed soluble (s) intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1 (sVCAM-1), and sE-selectin levels from the coronary sinuses of 25 cardiac allograft recipients, and we correlated these molecules with the degree of acute rejection detected in endomyocardial biopsy specimens and the presence of transplant vasculopathy assessed with coronary angiography. We found that sVCAM-1 significantly increased in patients with transplant vasculopathy compared with those without transplant vasculopathy, whereas sE-selectin and sICAM-1 did not. Therefore, increased coronary sinus levels of sVCAM-1 is a reliable marker in assessing cardiac transplant vasculopathy.

Soluble inflammatory markers in coronary sinus and peripheral blood of heart transplant recipients.

Cardiac allograft rejection is a focal inflammation and soluble markers are released into coronary sinus (CS). We investigated whether plasma-soluble markers in CS is better to predict the clinical status of transplant recipients than in peripheral blood (PB). Between February 1998 and January 2001, 51 patients admitted for endomyocardial biopsy were included. The clinical events of the transplant recipient were recorded as: early post-transplant, long-term uneventful status, infection, acute rejection and transplant coronary artery disease. The plasma levels of interleukin-2 (IL-2), tumor necrosis factor-alpha (TNF-alpha), ICAM-1, P-selectin, high-sensitive C-reactive protein (CRP) and troponin-I of CS and PB were determined. There were 71 blood samples. In patients within 1 month after heart transplant, there was a higher level of P-selectin, ICAM-1, CRP and troponin-I in CS and PB. In patients with infection, there was a higher level of all soluble markers except IL-2 in CS and PB. Patients with a long-term uneventful status had a lower level of CRP in PB but not in CS. Patients with acute rejection had a higher level of IL-2 in PB but not in CS. Patients with transplant coronary artery disease had a higher level of TNF-alpha in PB but not in CS. Soluble markers in CS failed to predict the occurrence of acute or chronic rejections.