In addition to scalability, human embryonic stem cells (hESCs) have the unique advantage of allowing their directed differentiation toward lineage-specific cells.
This study tested the feasibility of ...leveraging the properties of hESCs to generate clinical-grade cardiovascular progenitor cells and assessed their safety in patients with severe ischemic left ventricular dysfunction.
Six patients (median age 66.5 years interquartile range (IQR): 60.5 to 74.7 years; median left ventricular ejection fraction 26% IQR: 22% to 32%) received a median dose of 8.2 million (IQR: 5 to 10 million) hESC-derived cardiovascular progenitors embedded in a fibrin patch that was epicardially delivered during a coronary artery bypass procedure. The primary endpoint was safety at 1 year and focused on: 1) cardiac or off-target tumor, assessed by imaging (computed tomography and fluorine-18 fluorodeoxyglucose positron emission tomography scans); 2) arrhythmias, detected by serial interrogations of the cardioverter-defibrillators implanted in all patients; and 3) alloimmunization, assessed by the presence of donor-specific antibodies. Patients were followed up for a median of 18 months.
The protocol generated a highly purified (median 97.5% IQR: 95.5% to 98.7%) population of cardiovascular progenitors. One patient died early post-operatively from treatment-unrelated comorbidities. All others had uneventful recoveries. No tumor was detected during follow-up, and none of the patients presented with arrhythmias. Three patients developed clinically silent alloimmunization. All patients were symptomatically improved with an increased systolic motion of the cell-treated segments. One patient died of heart failure after 22 months.
This trial demonstrates the technical feasibility of producing clinical-grade hESC-derived cardiovascular progenitors and supports their short- and medium-term safety, thereby setting the grounds for adequately powered efficacy studies. (Transplantation of Human Embryonic Stem Cell-derived Progenitors in Severe Heart Failure ESCORT; NCT02057900)
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Surgical repair in patients with acute DeBakey type I aortic dissection (ADIAD) achieves good short-term results, but in several patients the false lumen remains patent in the descending aorta ...because of distal intimal tears with persisting risk for distal aneurismal evolution. We report the short- and mid-term outcomes of the stent-assisted balloon-induced intimal disruption and relamination of aortic dissection (STABILISE) technique for the 16 first patients treated for a residual dissection of the descending thoracic aorta after repaired ADIAD.
We reviewed all patients treated with STABILISE for a remaining distal thoracoabdominal aortic dissection after ADIAD repair.
From March 2016 to March 2018, 16 patients with previous surgery for ADIAD underwent the STABILISE procedure during the same hospitalization in a second-stage procedure to extend the repair within the descending thoracic aorta. The median age was 56 years (range, 43-65 years). Indication for the STABILISE procedure was persisting false lumen patency within the thoracic descending aorta associated with malperfusion symptoms in 13 patients and associated with dissecting aneurysm of the descending thoracic aorta >40 mm in 3 patients. Technical success was achieved in 100%. Eight (12.5%) renal arteries required stenting during the procedure. In-hospital mortality was 6% (n = 1). There was no stroke, spinal cord ischemia, ischemic colitis, or renal failure requiring dialysis. Median length of follow-up was 8 months (range, 3-24 months). One patient developed a proximal type 1 endoleak in the arch and required reintervention for proximal extension of the stent graft in zone 2. The primary visceral patency rate was 100%. There were no late deaths reported. At last computed tomography scan, all patients had complete aortic remodeling of the treated thoracoabdominal aorta with no aortic enlargement.
The STABILISE technique, in patients with remaining distal thoracoabdominal aortic dissection at the acute stage of a type A repair, allowed an immediate remodeling of the thoracoabdominal aorta, which should improve their long-term outcomes in terms of aortic-related events.
There is now compelling evidence that cells committed to a cardiac lineage are most effective for improving the function of infarcted hearts. This has been confirmed by our pre-clinical studies ...entailing transplantation of human embryonic stem cell (hESC)-derived cardiac progenitors in rat and non-human primate models of myocardial infarction. These data have paved the way for a translational programme aimed at a phase I clinical trial.
The main steps of this programme have included (i) the expansion of a clone of pluripotent hESC to generate a master cell bank under good manufacturing practice conditions (GMP); (ii) a growth factor-induced cardiac specification; (iii) the purification of committed cells by immunomagnetic sorting to yield a stage-specific embryonic antigen (SSEA)-1-positive cell population strongly expressing the early cardiac transcription factor Isl-1; (iv) the incorporation of these cells into a fibrin scaffold; (v) a safety assessment focused on the loss of teratoma-forming cells by in vitro (transcriptomics) and in vivo (cell injections in immunodeficient mice) measurements; (vi) an extensive cytogenetic and viral testing; and (vii) the characterization of the final cell product and its release criteria. The data collected throughout this process have led to approval by the French regulatory authorities for a first-in-man clinical trial of transplantation of these SSEA-1(+) progenitors in patients with severely impaired cardiac function.
Although several facets of this manufacturing process still need to be improved, these data may yet provide a useful platform for the production of hESC-derived cardiac progenitor cells under safe and cost-effective GMP conditions.
Shear wave imaging was evaluated for the in vivo assessment of myocardial biomechanical properties on ten open chest sheep. The use of dedicated ultrasonic sequences implemented on a very high frame ...rate ultrasonic scanner (>; 5000 frames per second) enables the estimation of the quantitative shear modulus of myocardium several times during one cardiac cycle. A 128 element probe remotely generates a shear wave thanks to the radiation force induced by a focused ultrasonic burst. The resulting shear wave propagation is tracked using the same probe by cross-correlating successive ultrasonic images acquired at a very high frame rate. The shear wave speed estimated at each location in the ultrasonic image gives access to the local myocardial stiffness (shear modulus μ). The technique was found to be reproducible (standard deviation <; 3%) and able to estimate both systolic and diastolic stiffness on each sheep (respectively μ dias ≈ 2 kPa and μ syst ≈ 30 kPa). Moreover, the ability of the proposed method to polarize the shear wave generation and propagation along a chosen axis permits the study the local elastic anisotropy of myocardial muscle. As expected, myocardial elastic anisotropy is found to vary with muscle depth. The real time capabilities and potential of Shear Wave Imaging using ultrafast scanners for cardiac applications is finally illustrated by studying the dynamics of this fractional anisotropy during the cardiac cycle.
Cell therapy holds promise for tissue regeneration, including in individuals with advanced heart failure. However, treatment of heart disease with bone marrow cells and skeletal muscle progenitors ...has had only marginal positive benefits in clinical trials, perhaps because adult stem cells have limited plasticity. The identification, among human pluripotent stem cells, of early cardiovascular cell progenitors required for the development of the first cardiac lineage would shed light on human cardiogenesis and might pave the way for cell therapy for cardiac degenerative diseases. Here, we report the isolation of an early population of cardiovascular progenitors, characterized by expression of OCT4, stage-specific embryonic antigen 1 (SSEA-1), and mesoderm posterior 1 (MESP1), derived from human pluripotent stem cells treated with the cardiogenic morphogen BMP2. This progenitor population was multipotential and able to generate cardiomyocytes as well as smooth muscle and endothelial cells. When transplanted into the infarcted myocardium of immunosuppressed nonhuman primates, an SSEA-1+ progenitor population derived from Rhesus embryonic stem cells differentiated into ventricular myocytes and reconstituted 20% of the scar tissue. Notably, primates transplanted with an unpurified population of cardiac-committed cells, which included SSEA-1- cells, developed teratomas in the scar tissue, whereas those transplanted with purified SSEA-1+ cells did not. We therefore believe that the SSEA-1+ progenitors that we have described here have the potential to be used in cardiac regenerative medicine.
Multiple needle-based injections of cells in the myocardium are associated with a low engraftment rate, which may limit the benefits of the procedure. This study used skeletal myoblasts to perform a ...head-to-head comparison of conventional injections with epicardial deposition of scaffold-embedded cells.
Four weeks after ligation-induced myocardial infarction, 40 rats were randomly allocated to receive intramyocardial injections of 5 million human skeletal myoblasts or control medium or to have the infarcted area covered with either a bilayer myoblast cell sheet prepared from a fibrin-coated culture plate or a myoblast-seeded collagen sponge (Gelfoam; Pharmacia & Upjohn, Kalamazoo, MI). End points, assessed after 1 month, included left ventricular function blindly measured by echocardiography, quantification of cell engraftment by quantitative real-time polymerase chain reaction and immunostaining, histologic assessment of fibrosis and angiogenesis, and tissue levels of host-specific angiogenic and antifibrotic cytokines.
Compared with control medium- or myoblast-injected hearts, those receiving the two cell constructs demonstrated the highest recoveries of left ventricular function (p = 0.004 versus controls). Both myoblast cell sheets and myoblast-seeded Gelfoam sponges also resulted in significantly greater angiogenesis compared with controls. The Gelfoam group was associated with the best outcome with regard to the number of engrafted donor cells (p = 0.03 versus myoblasts) and the reduction of fibrosis (p = 0.02 and p = 0.04 versus the control and myoblast groups, respectively).
Compared with injections, delivery of myoblasts in a construct overlaying the infarcted area is associated with better graft functionality, possibly because of maintenance of improved cell patterning. The cell-seeded Gelfoam construct was found to feature a user-friendly, reproducible, and atraumatic technique.
Cardiac-committed cells and biomimetic scaffolds independently improve the therapeutic efficacy of stem cells. In this study we tested the long-term effects of their combination.
Eighty ...immune-deficient rats underwent permanent coronary artery ligation. Five to 7 weeks later, those with an echocardiographically measured ejection fraction (EF) ≤55% were re-operated on and randomly allocated to receive a cell-free fibrin patch (n = 25), a fibrin patch loaded with 700,000 human embryonic stem cells (ESC) pre-treated to promote early cardiac differentiation (SSEA-1(+) progenitors n = 30), or to serve as sham-operated animals (n = 25). Left ventricular function was assessed by echocardiography at baseline and every month thereafter until 4 months. Hearts were then processed for assessment of fibrosis and angiogenesis and a 5-component heart failure score was constructed by integrating the absolute change in left ventricular end-systolic volume (LVESV) between 4 months and baseline, and the quantitative polymerase chain reaction (qPCR)-based expression of natriuretic peptides A and B, myosin heavy chain 7 and periostin. All data were recorded and analyzed in a blinded manner.
The cell-treated group consistently yielded better functional outcomes than the sham-operated group (p = 0.002 for EF; p = 0.01 for LVESV). Angiogenesis in the border zone was also significantly greater in the cell-fibrin group (p = 0.006), which yielded the lowest heart failure score (p = 0.04 vs sham). Engrafted progenitors were only detected shortly after transplantation; no grafted cells were identified after 4 months. There was no teratoma identified.
A fibrin scaffold loaded with ESC-derived cardiac progenitors resulted in sustained improvement in contractility and attenuation of remodeling without sustained donor cell engraftment. A paracrine effect, possibly on innate reparative responses, is a possible mechanism for this enduring effect.
Vagus nerve stimulation (VNS) is an established adjunctive therapy for pharmacologically refractory epilepsy and depression and is currently in active clinical research for other applications. In ...current clinical studies, VNS is delivered in an open-loop approach, where VNS parameters are defined during a manual titration phase. However, the physiological response to a given VNS configuration shows significant inter and intra-patient variability and may significantly evolve through time. VNS closed-loop approaches, allowing for the optimization of the therapy in an adaptive manner, may be necessary to improve efficacy while reducing side effects. This paper proposes a generic, closed-loop control VNS system that is able to optimize a number of VNS parameters in an adaptive fashion, in order to keep a control variable within a specified range. Although the proposed control method is completely generic, an example application using the cardiac beat to beat interval (RR) as control variable will be developed in this paper. The proposed controller is based on a state transition model (STM) that can be configured using a partially or a fully-connected architecture, different model orders and different state-transition algorithms. The controller is applied to the adaptive regulation of heart rate and evaluated on 6 sheep, for 13 different targets, using partially-connected STM with 10 states. Also, partially and fully-connected STM defined by 30 states were applied to 7 other sheep for the same 10 targets. Results illustrate the interest of the proposed fully-connected STM and the feasibility of integrating this control system into an implantable neuromodulator.
Although the therapeutic effects of Vagus Nerve Stimulation (VNS) have been recognized in pre-clinical and pilot clinical studies, the effect of different stimulation configurations on the ...cardiovascular response is still an open question, especially in the case of VNS delivered synchronously with cardiac activity. In this paper, we propose a formal mathematical methodology to analyze the acute cardiac response to different VNS configurations, jointly considering the chronotropic, dromotropic and inotropic cardiac effects. A latin hypercube sampling method was chosen to design a uniform experimental plan, composed of 75 different VNS configurations, with different values for the main parameters (current amplitude, number of delivered pulses, pulse width, interpulse period and the delay between the detected cardiac event and VNS onset). These VNS configurations were applied to 6 healthy, anesthetized sheep, while acquiring the associated cardiovascular response. Unobserved VNS configurations were estimated using a Gaussian process regression (GPR) model. In order to quantitatively analyze the effect of each parameter and their combinations on the cardiac response, the Sobol sensitivity method was applied to the obtained GPR model and inter-individual sensitivity markers were estimated using a bootstrap approach. Results highlight the dominant effect of pulse current, pulse width and number of pulses, which explain respectively 49.4%, 19.7% and 6.0% of the mean global cardiovascular variability provoked by VNS. More interestingly, results also quantify the effect of the interactions between VNS parameters. In particular, the interactions between current and pulse width provoke higher cardiac effects than the changes on the number of pulses alone (between 6 and 25% of the variability). Although the sensitivity of individual VNS parameters seems similar for chronotropic, dromotropic and inotropic responses, the interacting effects of VNS parameters provoke significantly different cardiac responses, showing the feasibility of a parameter-based functional selectivity. These results are of primary importance for the optimal, subject-specific definition of VNS parameters for a given therapy and may lead to new closed-loop methods allowing for the optimal adaptation of VNS therapy through time.
Heart failure develops after myocardial infarction and is a major cause of morbidity and mortality. The ability to direct differentiation of embryonic stem cells (ESC) towards a cardiomyogenic ...phenotype makes them an attractive therapeutic option for cardiac repair, but species-specific and individual-specific immunological imprinting remains a hurdle. Our aim was to ascertain whether the purported immune privilege of ESC allows for their cross-species engraftment in a clinically relevant large-animal model.
We studied engraftment and differentiation of cardiac-committed mouse ESC in 18 sheep in which a myocardial infarction had been induced; nine controls received medium and nine sheep (five of which were immunosuppressed) received ESC. The gain in myocardial function was measured by echocardiography 1 month after cell transplantation.
Cardiac-committed murine ESC engrafted in infarcted myocardium of immunosuppressed and immunocompetent sheep, and differentiated into mature cardiomyocytes that expressed connexins. Colonisation of the scar area by ESC was accompanied by a functional benefit of the damaged myocardium. Left-ventricular ejection fraction deteriorated in the control group by a median of 9·9% (range −20 to 0·3) relative to baseline (p=0·011) whereas in the treated group it improved by 6·6% (−5·7 to 50·8; comparison between groups p=0·002).
These findings obtained in a clinically relevant large-animal model of heart failure strengthen the potential therapeutic use of ESC to regenerate the severely dysfunctional myocardium and bring additional evidence for an immune privilege of these cells.
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