Marc Hendrikx

Recovery of Regional but Not Global Contractile Function by the Direct Intramyocardial Autologous Bone Marrow Transplantation Results From a Randomized Controlled Clinical Trial

Background— Recent trials have shown that intracoronary infusion of bone marrow cells (BMCs) improves functional recovery after acute myocardial infarction. However, whether this treatment is effective in heart failure as a consequence of remodeling after organized infarcts remains unclear. In this randomized trial, we assessed the hypothesis that direct intramyocardial injection of autologous mononuclear bone marrow cells during coronary artery bypass graft (CABG) could improve global and regional left ventricular ejection fraction (LVEF) at 4-month follow-up. Methods and Results— Twenty patients (age 64.8±8.7; 17 male, 3 female) with a postinfarction nonviable scar, as assessed by thallium (Tl) scintigraphy and cardiac magnetic resonance imaging (MRI), scheduled for elective CABG, were included. They were randomized to a control group (n =10, CABG only) or a BMC group (CABG and injection of 60.106±31.106 BMC). Primary end points were global LVEF change and wall thickening changes in the infarct area from baseline to 4-month follow-up, as measured by MRI. Changes in metabolic activity were measured by Tl scintigraphy and expressed as a score with a range from 0 to 4, corresponding to percent of maximal myocardial Tl uptake (4 indicates <50%, nonviable scar; 3, 50% to 60%; 2, 60% to 70%; 1, 70% to 80%; 0>80%). Global LVEF at baseline was 39.5±5.5% in controls and 42.9±10.3% in the BMC group (P=0.38). At 4 months, LVEF had increased to 43.1±10.9% in the control group and to 48.9±9.5% in the BMC group (P=0.23). Systolic thickening had improved from −0.6±1.3 mm at baseline to 1.8±2.6 mm at 4 months in the cell-implanted scars, whereas nontreated scars remained largely akinetic (−0.5±2.0 mm at baseline compared with 0.4±1.7 mm at 4 months, P=0.007 control versus BMC-treated group at 4 months). Defect score decreased from 4 to 3.3±0.9 in the BMC group and to 3.7±0.4 in the control group (P=0.18). Conclusions— At 4 months, there was no significant difference in global LVEF between both groups, but a recovery of regional contractile function in previously nonviable scar was observed in the BMC group.

The cardiac atrial appendage stem cell: a new and promising candidate for myocardial repair

AIMS Considerable shortcomings in the treatment of myocardial infarction (MI) still exist and therefore mortality remains high. Cardiac stem cell (CSC) therapy is a promising approach for myocardial repair. However, identification and isolation of candidate CSCs is mainly based on the presence or absence of certain cell surface markers, which suffers from some drawbacks. In order to find a more specific and reliable identification and isolation method, we investigated whether CSCs can be isolated based on the high expression of aldehyde dehydrogenase (ALDH). METHODS AND RESULTS An ALDH(+) stem cell population, the cardiac atrial appendage stem cells (CASCs), was isolated from human atrial appendages. CASCs possess a unique phenotype that is clearly different from c-kit(+) CSCs but that seems more related to the recently described cardiac colony-forming-unit fibroblasts. Based on immunophenotype and in vitro differentiation studies, we suggest that CASCs are an intrinsic stem cell population and are not mobilized from bone marrow or peripheral blood. Indeed, they possess a clonogenicity of 16% and express pluripotency-associated genes. Furthermore, compared with cardiosphere-derived cells, CASCs possess an enhanced cardiac differentiation capacity. Indeed, differentiated cells express the most important cardiac-specific genes, produce troponin T proteins, and have an electrophysiological behaviour similar to that of adult cardiomyocytes (CMs). Transplanting CASCs in the minipig MI model resulted in extensive cardiomyogenic differentiation without teratoma formation. CONCLUSION We have identified a new human CSC population able to differentiate into functional CMs. This opens interesting perspectives for cell therapy in patients with ischaemic heart disease.

Mesenchymal stem cell secreted platelet derived growth factor exerts a pro-migratory effect on resident Cardiac Atrial appendage Stem Cells

Mesenchymal stem cells (MSCs) modulate cardiac healing after myocardial injury through the release of paracrine factors, but the exact mechanisms are still unknown. One possible mechanism is through mobilization of endogenous cardiac stem cells (CSCs). This study aimed to test the pro-migratory effect of MSC conditioned medium (MSC-CM) on endogenous CSCs from human cardiac tissue. By using a three-dimensional collagen assay, we found that MSC-CM improved migration of cells from human cardiac tissue. Cell counts, perimeter and area measurements were utilized to quantify migration effects. To examine whether resident stem cells were among the migrating cells, specific stem cell properties were investigated. The migrating cells displayed strong similarities with resident Cardiac Atrial appendage Stem Cells (CASCs), including a clonogenic potential of ~21.5% and expression of pluripotency associated genes like Oct-4, Nanog, c-Myc and Klf-4. Similar to CASCs, migrating cells demonstrated high aldehyde dehydrogenase activity and were able to differentiate towards cardiomyocytes. Receptor tyrosine kinase analysis and collagen assays performed with recombinant platelet derived growth factor (PDGF)-AA and Imatinib Mesylate, a PDGF receptor inhibitor, suggested a role for the PDGF-AA/PDGF receptor α axis in enhancing the migration process of CASCs. In conclusion, our findings demonstrate that factors present in MSC-CM improve migration of resident stem cells from human cardiac tissue. These data open doors towards future therapies in which MSC secreted factors, like PDGF-AA, can be utilized to enhance the recruitment of CASCs towards the site of myocardial injury.

Ex vivo evaluation of a new neonatal/infant oxygenator: comparison of the Terumo CAPIOX® Baby RX with Dideco Lilliput 1 and Polystan Safe Micro in the piglet model

Objective: A newly developed neonatal and infant oxygenator with a nonheparin biocompatible polymer coating, low priming volume (43 mL), high oxygen transfer, wide operating range (<1.5 L/min) and low pressure drop represents a promising solution for cardiac surgery in neonates and infants. We compared the new CAPIOX® Baby RX, Terumo (BRX) with two commonly used neonatal oxygenators: Dideco Lilliput 1 (DL1) and Polystan Safe Micro (PSM) in a piglet model. Methods: Fifteen piglets (5.6±1.3 kg) were placed on standardized cardiopulmonary bypass (CPB) for 6 hours using one of the three oxygenators (n = 5 in each group). After 120 min, the system was cooled to 25°C for 60 min and then returned to normothermia. Arterial and venous blood gas data and temperature were recorded continuously by a CDI500 System (Terumo). Pressure drop, FiO2 and gas flow were recorded. Blood samples were taken before CBP, after 10 min, before and after cooling, and at the end. Total blood counts, thrombin-antithrombin complex and plasma-free haemoglobin (PfHb) were measured. Results: All oxygenators showed acceptable performance for the duration of CPB. The BRX had lower mean gas flow (0.33±0.05 L/min) and FiO2 (0.43± 0.02%) throughout CPB than the DL1 (1.14±0.25 L/min, p = 0.006 and 0.60±0.02%, p = 0.009, respectively) or the PSM (1.47±0.87 L/min and 0.54±0.08%, p = ns). Pressure drop in the BRX group ranged from 12 to 22 mmHg. This was significantly lower than in the DL1 group (39-65 mmHg, p = 0.005). In the PSM group, values ranged between 24 and 33 mmHg (p = ns). The increase in PfHb at six hours was significantly lower in the BRX (11.3±4.2 ng/dL) versus the DL1 (42.2±6.1 ng/dL, p = 0.004) and the PSM (56.7±15.5 ng/dL, p = 0.045). Conclusions: The BRX is as safe as the DL1 and the PSM, with superior performance in pressure drop, efficient blood gas management and lower haemolysis. The BRX exhibited the lowest prime, hold-up volume and breakthrough time.

Cardiac atrial appendage stem cells engraft and differentiate into cardiomyocytes in vivo: A new tool for cardiac repair after MI.

BACKGROUND This study assessed whether autologous transplantation of cardiac atrial appendage stem cells (CASCs) preserves cardiac function after myocardial infarction (MI) in a minipig model. METHODS AND RESULTS CASCs were isolated from right atrial appendages of Göttingen minipigs based on high aldehyde dehydrogenase activity and expanded. MI was induced by a 2h snare ligation of the left anterior descending coronary artery. Upon reperfusion, CASCs were intramyocardially injected under NOGA guidance (MI-CASC, n=10). Non-transplanted pigs (MI, n=8) received sham treatment. 3D electromechanical mapping (EMM) and cardiac MRI were performed to assess left ventricular (LV) function. MI pigs developed LV dilatation at 2 months (2M), while in the MI-CASC group volumes remained stable. Global LV ejection fraction decreased by 16 ± 8% in MI animals vs 3 ± 10% in MI-CASC animals and regional wall thickening in border areas was better preserved in the MI-CASC group. EMM showed decreased viability and wall motion in the LV for both groups POST-MI, whereas at 2M these parameters only improved in the MI-CASC. Substantial cell retention was accompanied by cardiomyogenic differentiation in 98±1% of the transplanted CASCs, which functionally integrated. Second harmonic generation microscopy confirmed the formation of mature sarcomeres in transplanted CASCs. Absence of cardiac arrhythmias indicated the safety of CASC transplantation. CONCLUSION CASCs preserve cardiac function by extensive engraftment and cardiomyogenic differentiation. Our data indicate the enormous potential of CASCs in myocardial repair.

Clinical-scale in vitro expansion preserves biological characteristics of cardiac atrial appendage stem cells

Cardiac atrial appendage stem cells (CASCs) have recently emerged as an attractive candidate for cardiac regeneration after myocardial infarction. As with other cardiac stem cells, CASCs have to be expanded ex vivo to obtain clinically relevant cell numbers. However, foetal calf serum (FCS), which is routinely used for cell culturing, is unsuitable for clinical purposes, and influence of long‐term in vitro culture on CASC behaviour is unknown.

Cardiac atrial appendage stem cells promote angiogenesis in vitro and in vivo

Cardiac atrial appendage stem cells (CASCs) show extraordinary myocardial differentiation properties, making them ideal candidates for myocardial regeneration. However, since the myocardium is a highly vascularized tissue, revascularization of the ischemic infarct area is essential for functional repair. Therefore, this study assessed if CASCs contribute to cardiac angiogenesis via paracrine mechanisms. First, it was demonstrated that CASCs produce and secrete high levels of numerous angiogenic growth factors, including vascular endothelial growth factor (VEGF), endothelin-1 (ET-1) and insulin-like growth factor binding protein 3 (IGFBP-3). Functional in vitro assays with a human microvascular endothelial cell line (HMEC-1) and CASC CM showed that CASCs promote endothelial cell proliferation, migration and tube formation, the most important steps of the angiogenesis process. Addition of inhibitory antibodies against identified growth factors could significantly reduce these effects, indicating their importance in CASC-induced neovascularization. The angiogenic potential of CASCs and CASC CM was also confirmed in a chorioallantoic membrane assay, demonstrating that CASCs promote blood vessel formation in vivo. In conclusion, this study shows that CASCs not only induce myocardial repair by cardiomyogenic differentiation, but also stimulate blood vessel formation by paracrine mechanisms. The angiogenic properties of CASCs further strengthen their therapeutic potential and make them an optimal stem cell source for the treatment of ischemic heart disease.

Amyloidoma of the chest wall: a rare entity

Amyloidoma (tumoral amyloidosis) is defined as a solitary localized tumor-like deposit of amyloid, in the absence of systemic amyloidosis. Amyloidoma is the least common presentation of tissue amyloid deposition, reported in many anatomic sites including the respiratory, genitourinary and gastrointestinal tracts, as well as the central nervous system, skin, breast and soft tissue. Amyloidoma of the chest wall is extremely rare, and to date only one case has been reported in literature. The authors present a case of a chest wall tumor that causes local destruction, being an amyloidoma on histopathologic examination. It was treated with wide local excision, with no recurrence during almost two years of follow-up. A search for occult systemic disease is recommended and was also performed.

Outcome after PORT in ypN2 or R1/R2 versus no PORT in ypN0 Stage III-N2 NSCLC after Induction Chemotherapy and Resection

Introduction We investigated patients with contemporarily staged and treated stage III‐N2 NSCLC treated with induction chemotherapy and surgery with or without postoperative radiotherapy (PORT). We focused on survival and toxicity and investigated what additional PORT may offer in patients with ypN2 status or incomplete resection. Methods We identified 161 patients with pathologically proven, resectable stage III‐N2 NSCLC from our prospective database who were treated between 1998 and 2012. Of these patients, 150 without progressive disease after chemotherapy underwent resection. Patients with ypN2 status or R1/2 resection received three‐dimensional PORT (n = 70) to a dose of 50 to 66 Gy in 2‐Gy fractions. Results The mean follow‐up time was 49 months. The 5‐year overall survival (OS) rate was 35.1% in intention‐to‐treat analysis; relapse‐free survival was 31.8%, the cumulative local recurrence (LR) rate was 50.9%, and the distant metastasis rate was 63.4%. The 5‐year OS, relapse‐free survival, and cumulative LR and distant metastasis rates were 32.0%, 32.9%, 47.0%, and 63.9% in the PORT group versus 38.1%, 30.7%, 54.1%, and 63.2% in the non‐PORT group. These results were not significantly different, even though patients in the PORT group had worse prognostic features. Cardiac toxicity was higher in the non‐PORT group (p = 0.02), but pulmonary toxicity was similar (p = 0.15). There was no difference between the two groups regarding dyspnea (p = 0.32), cough (p = 0.37), forced expiratory volume in 1 second (p = 0.30), and diffusing capacity of the lung for carbon monoxide (p = 0.61). Conclusions A similar outcome (OS, LR, and toxicity) was seen in both patient groups (PORT versus non‐PORT group). Despite the limitations of this retrospective study, PORT can be both effective and safe for patients with stage III‐N2 NSCLC with an R1/R2 resection or yN2 after induction chemotherapy and surgery.

Late organized left atrial thrombus on a left atrial appendage closure device.

Dilling-Boer, D (reprint author), Jessa Ziekenhuis, Dept Cardiol, Stadsomvaart 11, B-3500 Hasselt, Belgium. dagmara.dilling.boer@jessazh.be