Human MuStem cells are competent to fuse with nonhuman primate myofibers in a clinically relevant transplantation context: A proof-of-concept study.

We previously reported that human muscle-derived stem cells (hMuStem cells) contribute to tissue repair after local administration into injured skeletal muscle or infarcted heart in immunodeficient rodent models. However, extrapolation of these findings to a clinical context is problematic owing to the considerable differences often seen between in vivo findings in humans versus rodents. Therefore, we investigated whether the muscle regenerative behavior of hMuStem cells is maintained in a clinically relevant transplantation context. Human MuStem cells were intramuscularly administered by high-density microinjection matrices into nonhuman primates receiving tacrolimus-based immunosuppression thereby reproducing the protocol that has so far produced the best results in clinical trials of cell therapy in myopathies. Four and 9 weeks after administration, histological analysis of cell injection sites revealed large numbers of hMuStem cell-derived nuclei in all cases. Most graft-derived nuclei were distributed in small myofiber groups in which no signs of a specific immune response were observed. Importantly, hMuStem cells contributed to simian tissue repair by fusing mainly with host myofibers, demonstrating their capacity for myofiber regeneration in this model. Together, these findings obtained in a valid preclinical model provide new insights supporting the potential of hMuStem cells in future cell therapies for muscle diseases.

Deciphering Transcriptional Networks during Human Cardiac Development.

Human heart development is governed by transcription factor (TF) networks controlling dynamic and temporal gene expression alterations. Therefore, to comprehensively characterize these transcriptional regulations, day-to-day transcriptomic profiles were generated throughout the directed cardiac differentiation, starting from three distinct human- induced pluripotent stem cell lines from healthy donors (32 days). We applied an expression-based correlation score to the chronological expression profiles of the TF genes, and clustered them into 12 sequential gene expression waves. We then identified a regulatory network of more than 23,000 activation and inhibition links between 216 TFs. Within this network, we observed previously unknown inferred transcriptional activations linking IRX3 and IRX5 TFs to three master cardiac TFs: GATA4, NKX2-5 and TBX5. Luciferase and co-immunoprecipitation assays demonstrated that these five TFs could (1) activate each other's expression; (2) interact physically as multiprotein complexes; and (3) together, finely regulate the expression of SCN5A, encoding the major cardiac sodium channel. Altogether, these results unveiled thousands of interactions between TFs, generating multiple robust hypotheses governing human cardiac development.

FACS-assisted CRISPR-Cas9 genome editing of human induced pluripotent stem cells.

This manuscript proposes an efficient and reproducible protocol for the generation of genetically modified human induced pluripotent stem cells (hiPSCs) by genome editing using CRISPR-Cas9 technology. Here, we describe the experimental strategy for generating knockout (KO) and knockin (KI) clonal populations of hiPSCs using single-cell sorting by flow cytometry. We efficiently achieved up to 15 kb deletions, molecular tag insertions, and single-nucleotide editing in hiPSCs. We emphasize the efficacy of this approach in terms of cell culture time. For complete details on the use and execution of this protocol, please refer to Canac et al. (2022) and Bray et al. (2022).

Geographical Ambulatory Endovascular Revascularisation Disparities in France From 2015 to 2019.

OBJECTIVE: Despite efficiency and safety evidence, ambulatory endovascular revascularisation for lower extremity arterial disease (LEAD) accounted for only 5% of interventions in France in 2016. Such a low rate suggests temporal and geographical space disparities. The aim of this study was to describe the space-time development of ambulatory endovascular revascularisation for LEAD in France and to investigate the contributions of healthcare services and population characteristics as potential determinants. METHODS: A retrospective study of discharge data from French hospitals that performed endovascular procedures for LEAD between 2015 and 2019 was conducted. Space-time analyses with Moran's Index, zero inflated Poisson regression, and clustering approaches were applied. Spatial clusters were compared on the basis of healthcare services and population characteristics (including poverty and single man household as proxies of social isolation). RESULTS: Between 2015 and 2019, the number of ambulatory interventions tripled (1 104 vs.3 130). Of the 86 French departments, the proportion with >5% of ambulatory interventions increased from 10.7% to 28.7% over the study period. In 2019, ambulatory activity in French departments ranged from 0% to 39%. This change was accompanied by a northwest to northeast spatial trend. The clusters of 27 departments with substantial ambulatory activity differed from the others notably by the mortality rate of lower limb arterial thromboembolic diseases in males (OR 3.15, 95% CI 1.2-8.1), the proportion of single man households of age ≥75 (OR 0.37, 95% CI 0.2-0.8), and the poverty rate of people aged 50-59 years (OR 0.69, 95% CI 0.5-0.9). CONCLUSIONS: The development of ambulatory interventions for LEAD in France is encouraging but heterogeneous. Some determinants of this evolution are clearly population based, with a positive impact of needs to take care of the burden of LEAD but negative effects of social isolation and poverty. Research should be conducted to overcome some patient constraints such as isolation.

Generation of human induced pluripotent stem cell lines from three patients affected by Catecholaminergic Polymorphic ventricular tachycardia (CPVT) carrying heterozygous mutations in RYR2 gene.

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is an exercise and emotional stress-induced life-threatening inherited heart rhythm disorder, characterized by an abnormal cellular calcium homeostasis. Most reported cases have been linked to mutations in the gene encoding the type 2 ryanodine receptor gene, RYR2. We generated induced pluripotent stem cells (hiPSCs) from peripheral blood mononuclear cells (PBMC) from three CPVT-affected patients, two of them carrying p.R4959Q mutation and one carrying p.Y2476D mutation. These generated hiPSC lines are a useful model to study pathophysiological consequences of RYR2 dysfunction in humans and the molecular basis of CPVT.

Generation of human induced pluripotent stem cell lines from four unrelated healthy control donors carrying European genetic background.

Four human induced pluripotent stem cell (hiPSC) lines have been generated from healthy control European donors, and validated. This resource represents a useful tool for stem cell-based research, as references for developmental studies and disease modeling linked to any type of human tissue and organ, in an ethnical-, sex- and age-matched context. They providea reliable in-vitro model for single cell- and tissue-based investigations, and are also a valuable tool for genome editing-based studies.

Human MuStem cells repress T-cell proliferation and cytotoxicity through both paracrine and contact-dependent pathways.

BACKGROUND: Muscular dystrophies (MDs) are inherited diseases in which a dysregulation of the immune response exacerbates disease severity and are characterized by infiltration of various immune cell types leading to muscle inflammation, fiber necrosis and fibrosis. Immunosuppressive properties have been attributed to mesenchymal stem cells (MSCs) that regulate the phenotype and function of different immune cells. However, such properties were poorly considered until now for adult stem cells with myogenic potential and advanced as possible therapeutic candidates for MDs. In the present study, we investigated the immunoregulatory potential of human MuStem (hMuStem) cells, for which we previously demonstrated that they can survive in injured muscle and robustly counteract adverse tissue remodeling. METHODS: The impact of hMuStem cells or their secretome on the proliferative and phenotypic properties of T-cells was explored by co-culture experiments with either peripheral blood mononucleated cells or CD3-sorted T-cells. A comparative study was produced with the bone marrow (BM)-MSCs. The expression profile of immune cell-related markers on hMuStem cells was determined by flow cytometry while their secretory profile was examined by ELISA assays. Finally, the paracrine and cell contact-dependent effects of hMuStem cells on the T-cell-mediated cytotoxic response were analyzed through IFN-γ expression and lysis activity. RESULTS: Here, we show that hMuStem cells have an immunosuppressive phenotype and can inhibit the proliferation and the cytotoxic response of T-cells as well as promote the generation of regulatory T-cells through direct contact and via soluble factors. These effects are associated, in part, with the production of mediators including heme-oxygenase-1, leukemia inhibitory factor and intracellular cell adhesion molecule-1, all of which are produced at significantly higher levels by hMuStem cells than BM-MSCs. While the production of prostaglandin E2 is involved in the suppression of T-cell proliferation by both hMuStem cells and BM-MSCs, the participation of inducible nitric oxide synthase activity appears to be specific to hMuStem cell-mediated one. CONCLUSIONS: Together, our findings demonstrate that hMuStem cells are potent immunoregulatory cells. Combined with their myogenic potential, the attribution of these properties reinforces the positioning of hMuStem cells as candidate therapeutic agents for the treatment of MDs.

Generation of human induced pluripotent stem cell lines from two patients affected by catecholamine-induced QT prolongation (CIQTP).

Catecholamine-induced QT prolongation (CIQTP) is an inherited cardiac disease characterized by a normal baseline ECG and a risk of sudden cardiac death by ventricular arrhythmia due to a QT prolongation that only appears during catecholergic stimulation, especially mental stress. Induced pluripotent stem cells (hiPSCs) were generated from peripheral blood mononuclear cells collected from two CIQTP-affected patients from two different families. These two hiPSC lines are a valuable model to study biological alterations due to CIQTP.

Generation of three human induced pluripotent stem cell lines with IRX5 knockout and knockin genetic editions using CRISPR-Cas9 system.

Studies on animal models have shown that Irx5 is an important regulator of cardiac development and that it regulates ventricular electrical repolarization gradient in the adult heart. Mutations in IRX5 have also been linked in humans to cardiac conduction defects. In order to fully characterize the role of IRX5 during cardiac development and in cardiomyocyte function, we generated three genetically-modified human induced pluripotent stem cell lines: two knockout lines (heterozygous and homozygous) and a knockin HA-tagged line (homozygous).

Human model of IRX5 mutations reveals key role for this transcription factor in ventricular conduction.

AIMS: Several inherited arrhythmic diseases have been linked to single gene mutations in cardiac ion channels and interacting proteins. However, the mechanisms underlying most arrhythmias, are thought to involve altered regulation of the expression of multiple effectors. In this study, we aimed to examine the role of a transcription factor (TF) belonging to the Iroquois homeobox family, IRX5, in cardiac electrical function. METHODS AND RESULTS: Using human cardiac tissues, transcriptomic correlative analyses between IRX5 and genes involved in cardiac electrical activity showed that in human ventricular compartment, IRX5 expression strongly correlated to the expression of major actors of cardiac conduction, including the sodium channel, Nav1.5, and Connexin 40 (Cx40). We then generated human-induced pluripotent stem cells (hiPSCs) derived from two Hamamy syndrome-affected patients carrying distinct homozygous loss-of-function mutations in IRX5 gene. Cardiomyocytes derived from these hiPSCs showed impaired cardiac gene expression programme, including misregulation in the control of Nav1.5 and Cx40 expression. In accordance with the prolonged QRS interval observed in Hamamy syndrome patients, a slower ventricular action potential depolarization due to sodium current reduction was observed on electrophysiological analyses performed on patient-derived cardiomyocytes, confirming the functional role of IRX5 in electrical conduction. Finally, a cardiac TF complex was newly identified, composed by IRX5 and GATA4, in which IRX5 potentiated GATA4-induction of SCN5A expression. CONCLUSION: Altogether, this work unveils a key role for IRX5 in the regulation of human ventricular depolarization and cardiac electrical conduction, providing therefore new insights into our understanding of cardiac diseases.

The use of single-pill combinations as first-line treatment for hypertension: translating guidelines into clinical practice.

: The 2008 European Society of Cardiology/European Society of Hypertension guidelines recommend the first-line prescription of two antihypertensive drugs in single-pill combinations (SPCs), also known as fixed-dose combinations, for the treatment of most patients with hypertension. This recommendation is based on a large amount of data, which shows that first-line treatment with SPCs supports reaching blood pressure targets rapidly and reducing cardiovascular outcome risk while keeping the therapeutic strategies as simple as possible and fostering adherence and persistence. As this approach constitutes a big shift from the stepped-care approaches that have been dominant for many years, practicing physicians have expressed concerns about using SPCs as first-line agents. In this review, we will discuss the barriers to the uptake of this recommendation. We will also offer suggestions to reduce the impact of these barriers and address specific concerns that have been raised.

Duration of sick leave after same-day discharge for lower extremity arterial disease and varicose vein interventions in active population of French patients, 2013-2016: observational study.

OBJECTIVE: To assess whether disparities in rates of same-day discharge for lower extremities arterial disease (5%) and varicose vein interventions (90%) are associated with the burden of postprocedural rehabilitation process, measured through the duration of sick leave. DESIGN: Retrospective observational study using French National Health Insurance data in 2012-2016. SETTING: The French National Health Data System (Système National des Données de Santé), which covers 98.8% of the 66 million people in the French population. PARTICIPANTS: French workforce population aged 18 to 65 years old who underwent a first angioplasty with stent placement for lower extremities arterial disease (LEAD, n=30 238) or a first varicose vein intervention (n=265 670) between 2013 and 2016. MAIN OUTCOME MEASURES: Duration and renewals of sick leave within 180 days after endovascular intervention, continuity of care and prescription indices to assess coordination among healthcare professionals after intervention associated with specific intervention settings: conventional (inpatient) or same-day discharge (outpatient). Association was estimated by multivariate negative binomial regressions adjusting for age, gender and comorbidities. RESULTS: Outpatient settings decrease the incidence rate ratio (IRR) of the number of cumulated days of sick leave by 14% in both interventions. The increasing variety of prescribers decreases the IRR of cumulated days of sick leave and prescription renewals for varicose interventions by 25% and 21%, respectively, but increases them for LEAD interventions by 240% and 106%. Less coordination between healthcare specialists increases the IRR of cumulative days of sick leave and renewals by 37% and 29% for varicose, and 11% and 9% for LEAD interventions. CONCLUSIONS: Low rates of outpatients in LEAD angioplasty does not seem related to the duration of sick leave. Outpatient setting reduces the duration of sick leave and their renewals, whatever the intervention. Coordination of healthcare professionals is a key element of interventions follow-up with pathology specificities.

Resistant Hypertension: Novel Insights.

Hypertension is the most common chronic disease and the leading risk factor for disability and premature deaths in the world, accounting for more than 9 million deaths annually. Resistant hypertension is a particularly severe form of hypertension. It was described 50 years ago and since then has been a very active field of research. This review aims at summarizing the most recent findings on resistant hypertension. The recent concepts of apparent- and true-resistant hypertension have stimulated a more precise definition of resistant hypertension taking into account not only the accuracy of blood pressure measurement and pharmacological class of prescribed drugs but also patient adherence to drugs and life-style recommendations. Recent epidemiological studies have reported a 10% prevalence of resistant hypertension among hypertensive subjects and demonstrated the high cardiovascular risk of these patients. In addition, these studies identified subgroups of patients with even higher morbidity and mortality risk, probably requiring a more aggressive medical management. In the meantime, guidelines provided more standardized clinical work-up to identify potentially reversible causes for resistant hypertension such as secondary hypertension. The debate is however still ongoing on which would be the optimal method(s) to screen for non-adherence to hypertension therapy, recognized as the major cause for (pseudo)-resistance to treatment. Recent randomized clinical trials have demonstrated the strong benefit of anti-aldosterone drugs (mostly spironolocatone) as fourth-line therapies in resistant hypertension whereas clinical trials with device-based therapies displayed contrasting results. New trials with improved devices and more carefully selected patients with resistant hypertension are ongoing.

Deconditioning, fatigue and impaired quality of life in long-term survivors after allogeneic hematopoietic stem cell transplantation.

Long-term survivors after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are at high risk for treatment-related adverse events, that may worsen physical capacity and may induce fatigue and disability. The aims of this prospective study were to evaluate exercise capacity in allotransplant survivors and its relationship with fatigue and disability. Patient-reported outcomes and exercise capacity were evaluated in 71 non-relapse patients 1 year after allo-HSCT, using validated questionnaires, cardiopulmonary exercise testing (CPET) with measure of peak oxygen uptake (peakVO2) and deconditioning, pulmonary function testing, echocardiography and 6-min walk test. A high proportion (75.4%) of allo-HSCT survivors showed abnormal cardiopulmonary exercise testing parameters as compared to predicted normal values, including 49.3% patients who exhibited moderate to severe impairment in exercise capacity and 37.7% patients with physical deconditioning. PeakVO2 values were not accurately predicted by 6-min walk distances (r = 0.53). Disability and fatigue were strongly associated with decreased peakVO2 values (p = 0.002 and p = 0.008, respectively). Exercise capacity was reduced in most allo-HSCT long-term survivors. Because reduced exercise capacity was associated with fatigue, disability and a decrease in quality of life, cardiopulmonary exercise testing should be performed in every patient who reports fatigue and disability.

Sustained quality of life improvement after intracoronary injection of autologous bone marrow cells in the setting of acute myocardial infarction: results from the BONAMI trial.

PURPOSE: Cardiac cell therapy is a promising treatment for acute myocardial infarction (AMI), leading to cardiac function improvement. However, whether it translates into quality of life (QoL) improvement is unclear. We hypothesized that administration of bone marrow cells (BMC) to patients with AMI improves QoL. METHODS: In the multicenter BONAMI trial (NCT00200707), patients with reperfused AMI and decreased myocardial viability were randomized to intracoronary autologous BMC infusion (n = 52) or state-of-the-art therapy (n = 49). QoL data, derived from the Minnesota Living with Heart Failure questionnaire (MLHFQ), were obtained 1, 3, and 12 months after AMI and analyzed using a Rasch-family model. RESULTS: Using this model, QoL improved over time in the BMC group (p = 0.025) but not in the control group. Furthermore, the BMC-group patients displayed a better QoL than the control-group patients at 3 and 12 months post-AMI (p = 0.034 and p = 0.003, respectively). These findings were not detected when analyzing MLHFQ data using a standard method. Cardiac function, myocardial viability, mortality, and number of major adverse cardiac events did not differ between treatment groups. CONCLUSION: Our results suggest that BMC therapy can improve QoL, stressing the need for confirmation trials and for systematic QoL assessment in cardiac cell therapy trials .

HIV-Tat induces a decrease in IKr and IKsvia reduction in phosphatidylinositol-(4,5)-bisphosphate availability.

Patients with HIV present with a higher prevalence of QT prolongation, of which molecular bases are still not clear. Among HIV proteins, Tat serves as a transactivator that stimulates viral genes expression and is required for efficient HIV replication. Tat is actively secreted into the blood by infected T-cells and affects organs such as the heart. Tat has been shown to alter cardiac repolarization in animal models but how this is mediated and whether this is also the case in human cells is unknown. In the present study, we show that Tat transfection in heterologous expression systems led to a decrease in hERG (underlying cardiac IKr) and human KCNE1-KCNQ1 (underlying cardiac IKs) currents and to an acceleration of their deactivation. This is consistent with a decrease in available phosphatidylinositol-(4,5)-bisphosphate (PIP2). A mutant Tat, unable to bind PIP2, did not reproduce the observed effects. In addition, WT-Tat had no effect on a mutant KCNQ1 which is PIP2-insensitive, further confirming the hypothesis. Twenty-four-hour incubation of human induced pluripotent stem cells-derived cardiomyocytes with Wild-type Tat reduced IKr and accelerated its deactivation. Concordantly, this Tat incubation led to a prolongation of the action potential (AP) duration. Events of AP alternans were also recorded in the presence of Tat, and were exacerbated at a low pacing cycle length. Altogether, these data obtained on human K+ channels both in heterologous expression systems and in human cardiomyocytes suggest that Tat sequesters PIP2, leading to a reduction of IKr and IKs, and provide a molecular mechanism for QT prolongation in HIV-infected patients.

Predictors of ventricular remodelling in patients with reperfused acute myocardial infarction and left ventricular dysfunction candidates for bone marrow cell therapy: insights from the BONAMI trial.

PURPOSE: Few data are available regarding the relation of left ventricular (LV) mechanical dyssynchrony to remodelling after acute myocardial infarction (MI) and stem cell therapy. We evaluated the 1-year time course of both LV mechanical dyssynchrony and remodelling in patients enrolled in the BONAMI trial, a randomized, multicenter controlled trial assessing cell therapy in patients with reperfused MI. METHODS: Patients with acute MI and ejection fraction (EF) ≤ 45 % were randomized to cell therapy or to control and underwent thallium single-photon emission computed tomography (SPECT), radionuclide angiography, and echocardiography at baseline, 3 months, and 1 year. Eighty-three patients with a comprehensive 1-year follow-up were included. LV dyssynchrony was assessed by the standard deviation (SD) of the LV phase histogram using radionuclide angiography. Remodelling was defined as a 20 % increase in LV end-systolic volume index (LVESVI) at 1 year. RESULTS: At baseline, LVEF, wall motion score index, and perfusion defect size were significantly impaired in the 43 patients (52 %) with LV remodelling (all p < 0.001), without significant increase in LV mechanical dyssynchrony. During follow-up, there was a progressive increase in LV SD (p = 0.01). Baseline independent predictors of LV remodelling were perfusion SPECT defect size (p = 0.001), LVEF (p = 0.01) and a history of hypertension (p = 0.043). Bone marrow cell therapy did not affect the time-course of LV remodelling and dyssynchrony. CONCLUSIONS: LV remodelling 1 year after reperfused MI is associated with progressive LV dyssynchrony and is related to baseline infarct size and ejection fraction, without impact of cell therapy on this process.

NADPH oxidase-2 inhibition restores contractility and intracellular calcium handling and reduces arrhythmogenicity in dystrophic cardiomyopathy.

Duchenne muscular dystrophy may affect cardiac muscle, producing a dystrophic cardiomyopathy in humans and the mdx mouse. We tested the hypothesis that oxidative stress participates in disrupting calcium handling and contractility in the mdx mouse with established cardiomyopathy. We found increased expression (fivefold) of the NADPH oxidase (NOX) 2 in the mdx hearts compared with wild type, along with increased superoxide production. Next, we tested the impact of NOX2 inhibition on contractility and calcium handling in isolated cardiomyocytes. Contractility was decreased in mdx myocytes compared with wild type, and this was restored toward normal by pretreating with apocynin. In addition, the amplitude of evoked intracellular Ca(2+) concentration transients that was diminished in mdx myocytes was also restored with NOX2 inhibition. Total sarcoplasmic reticulum (SR) Ca(2+) content was reduced in mdx hearts and normalized by apocynin treatment. Additionally, NOX2 inhibition decreased the production of spontaneous diastolic calcium release events and decreased the SR calcium leak in mdx myocytes. In addition, nitric oxide (NO) synthase 1 (NOS-1) expression was increased eightfold in mdx hearts compared with wild type. Nevertheless, cardiac NO production was reduced. To test whether this paradox implied NOS-1 uncoupling, we treated cardiac myocytes with exogenous tetrahydrobioterin, along with the NOX inhibitor VAS2870. These agents restored NO production and phospholamban phosphorylation in mdx toward normal. Together, these results demonstrate that, in mdx hearts, NOX2 inhibition improves the SR calcium handling and contractility, partially by recoupling NOS-1. These findings reveal a new layer of nitroso-redox imbalance in dystrophic cardiomyopathy.

Difference in mobilization of progenitor cells after myocardial infarction in smoking versus non-smoking patients: insights from the BONAMI trial.

INTRODUCTION: Although autologous bone marrow cell (BMC) therapy has emerged as a promising treatment for acute myocardial infarction (AMI), trials reported mixed results. In the BONAMI trial, active smoking reduced cardiac function recovery after reperfused AMI. Therefore, we hypothesized that variability in the functionality of BMCs retrieved from patients with cardiovascular risk factors may partly explain these mixed results. We investigated the characteristics of progenitor cells in active smokers and non-smokers with AMI and their potential impact on BMC therapy efficacy. METHODS: Bone marrow and blood samples from 54 smoking and 47 non-smoking patients enrolled in the BONAMI cell therapy trial were analyzed. RESULTS: The white BMC and CD45dimCD34+ cell numbers were higher in active smokers (P = 0.001, P = 0.03, respectively). In marked contrast, either bone marrow or blood endothelial progenitor CD45dimCD34 + KDR + cells (EPCs) were decreased in active smokers (P = 0.005, P = 0.04, respectively). Importantly, a multivariate analysis including cardiovascular risk factors confirmed the association between active smoking and lower EPC number in bone marrow (P = 0.04) and blood (P = 0.04). Furthermore, baseline circulating EPC count predicted infarct size decrease at three months post-AMI in non-smokers (P = 0.01) but not in active smokers. Interestingly, baseline circulating EPCs were no longer predictive of cardiac function improvement in the BMC therapy group. CONCLUSIONS: These data suggest that circulating EPCs play an important role in cardiac repair post-AMI only in non-smokers and that active smoking-associated EPC alterations may participate in the impairment of cardiac function recovery observed in smokers after AMI, an effect that was overridden by BMC therapy.