Transcription factor-based cellular reprogramming has opened the way to converting somatic cells to a pluripotent state, but has faced limitations resulting from the requirement for transcription ...factors and the relative inefficiency of the process. We show here that expression of the
miR302/367 cluster rapidly and efficiently reprograms mouse and human somatic cells to an iPSC state without a requirement for exogenous transcription factors. This miRNA-based reprogramming approach is two orders of magnitude more efficient than standard Oct4/Sox2/Klf4/Myc-mediated methods. Mouse and human
miR302/367 iPSCs display similar characteristics to Oct4/Sox2/Klf4/Myc-iPSCs, including pluripotency marker expression, teratoma formation, and, for mouse cells, chimera contribution and germline contribution. We found that
miR367 expression is required for
miR302/367-mediated reprogramming and activates
Oct4 gene expression, and that suppression of Hdac2 is also required. Thus, our data show that miRNA and Hdac-mediated pathways can cooperate in a powerful way to reprogram somatic cells to pluripotency.
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► miRNAs alone can reprogram somatic cells to pluripotency ► The miR302/367 cluster reprograms both mouse and human fibroblasts ► miR367 is required for miR302/367 reprogramming ► Low Hdac2 levels are required for miR302/367 reprogramming
Objective To describe cumulative radiation exposure in a large single-center cohort of children with congenital heart disease (CHD) and identify risk factors for greater exposure. Study design A ...detailed medical radiation exposure history was collected retrospectively for patients aged <18 years who underwent surgery for CHD between January 1, 2001, and July 22, 2009. Cumulative per patient exposure was quantified as the effective dose in millisieverts (mSv) and annualized (mSv/year). Results A total of 4132 patients were subjected to 134 715 radiation examinations at a median follow-up of 4.3 years (range, 0-8.6 years). Exposure clustered around the time of surgery. The median exposure was 14 radiologic tests (the majority of which were plain film radiographs) at an effective dose of 0.96 mSv (the majority of which was from cardiac catheterization), although this distribution had a very wide range. Almost three-quarters (73.7%) were exposed to <3 mSv/year, and 5.3% were exposed to >20 mSv/year. Neonates, children with genetic syndromes, and children requiring surgery for cardiomyopathy, pulmonary valve, single ventricle, or tricuspid valve diseases were more likely to have higher exposure levels, and those requiring surgery for aortic arch anomalies or atrioventricular septal defects were more likely to have lower levels. Conclusion Children with CHD requiring surgery are exposed to numerous medical forms of ionizing radiation. Although the majority of patients receive <3 mSv/year, there are identifiable risk factors for higher exposure levels. This may have important health implications as these patients age.
Diaphragm plication: When and why to do it Gruber, Peter J.
The Journal of thoracic and cardiovascular surgery,
November 2017, 2017-11-00, 20171101, Volume:
154, Issue:
5
Journal Article
Objectives Surgical closure of ventricular septal defects remains the most common pediatric cardiac surgical procedure. No studies, however, have comprehensively analyzed risk factors and drivers of ...nonmortality outcomes in the current era. The purpose of this study was to assess both baseline characteristics and outcomes of children undergoing surgical repair of ventricular septal defects in a contemporary cohort. Methods This retrospective study examined a consecutive series of 369 ventricular septal defect closures at a single institution. Because mortality is low in nearly all centers for repair of these defects, we focused on morbidity and identified drivers of risk via multivariable linear regression modeling. Results For children younger than age 6 months undergoing ventricular septal defect closure, every extra kilogram in operative weight results in a 2.3-day shorter length of stay. In an analysis of composite risk, patients younger than age 6 months undergoing ventricular septal defect repair exhibited a 1.8-fold increase in composite risk for each kilogram decrease in weight, whereas patients older than age 6 months experienced no significant difference. Conclusions Even in the current surgical era, weight remains a significant predictor of morbidity and driver or length of stay in young infants undergoing ventricular septal defect closure. Weight still should be considered when discussing operative risks for children younger than age 6 months undergoing this procedure, irrespective of the indication for operation.
Embryonic development is largely conserved among mammals. However, certain genes show divergent functions. By generating a transcriptional atlas containing >30,000 cells from post-implantation ...non-human primate embryos, we uncover that ISL1, a gene with a well-established role in cardiogenesis, controls a gene regulatory network in primate amnion. CRISPR/Cas9-targeting of ISL1 results in non-human primate embryos which do not yield viable offspring, demonstrating that ISL1 is critically required in primate embryogenesis. On a cellular level, mutant ISL1 embryos display a failure in mesoderm formation due to reduced BMP4 signaling from the amnion. Via loss of function and rescue studies in human embryonic stem cells we confirm a similar role of ISL1 in human in vitro derived amnion. This study highlights the importance of the amnion as a signaling center during primate mesoderm formation and demonstrates the potential of in vitro primate model systems to dissect the genetics of early human embryonic development.
In the Single Ventricle Reconstruction (SVR) trial, 1-year transplantation-free survival was better for the Norwood procedure with right ventricle-to-pulmonary artery shunt (RVPAS) compared with a ...modified Blalock-Taussig shunt (MBTS). At 3 years, we compared transplantation-free survival, echocardiographic right ventricular ejection fraction, and unplanned interventions in the treatment groups.
Vital status and medical history were ascertained from annual medical records, death indexes, and phone interviews. The cohort included 549 patients randomized and treated in the SVR trial. Transplantation-free survival for the RVPAS versus MBTS groups did not differ at 3 years (67% versus 61%; P=0.15) or with all available follow-up of 4.8±1.1 years (log-rank P=0.14). Pre-Fontan right ventricular ejection fraction was lower in the RVPAS group than in the MBTS group (41.7±5.1% versus 44.7±6.0%; P=0.007), and right ventricular ejection fraction deteriorated in RVPAS (P=0.004) but not MBTS (P=0.40) subjects (pre-Fontan minus 14-month mean, -3.25±8.24% versus 0.99±8.80%; P=0.009). The RVPAS versus MBTS treatment effect had nonproportional hazards (P=0.004); the hazard ratio favored the RVPAS before 5 months (hazard ratio=0.63; 95% confidence interval, 0.45-0.88) but the MBTS beyond 1 year (hazard ratio=2.22; 95% confidence interval, 1.07-4.62). By 3 years, RVPAS subjects had a higher incidence of catheter interventions (P<0.001) with an increasing HR over time (P=0.005): <5 months, 1.14 (95% confidence interval, 0.81-1.60); from 5 months to 1 year, 1.94 (95% confidence interval, 1.02-3.69); and >1 year, 2.48 (95% confidence interval, 1.28-4.80).
By 3 years, the Norwood procedure with RVPAS compared with MBTS was no longer associated with superior transplantation-free survival. Moreover, RVPAS subjects had slightly worse right ventricular ejection fraction and underwent more catheter interventions with increasing hazard ratio over time.
http://www.clinicaltrials.gov. Unique identifier: NCT00115934.
Congenital heart disease (CHD) is the most common birth abnormality and the etiology is unknown in the overwhelming majority of cases. ISLET1 (ISL1) is a transcription factor that marks cardiac ...progenitor cells and generates diverse multipotent cardiovascular cell lineages. The fundamental role of ISL1 in cardiac morphogenesis makes this an exceptional candidate gene to consider as a cause of complex congenital heart disease. We evaluated whether genetic variation in ISL1 fits the common variant-common disease hypothesis. A 2-stage case-control study examined 27 polymorphisms mapping to the ISL1 locus in 300 patients with complex congenital heart disease and 2,201 healthy pediatric controls. Eight genic and flanking ISL1 SNPs were significantly associated with complex congenital heart disease. A replication study analyzed these candidate SNPs in 1,044 new cases and 3,934 independent controls and confirmed that genetic variation in ISL1 is associated with risk of non-syndromic congenital heart disease. Our results demonstrate that two different ISL1 haplotypes contribute to risk of CHD in white and black/African American populations.
Photodegradable hydrogels have emerged as useful platforms for research on cell function, tissue engineering, and cell delivery as their physical and chemical properties can be dynamically controlled ...by the use of light. The photo‐induced degradation of such hydrogel systems is commonly based on the integration of photolabile o‐nitrobenzyl derivatives to the hydrogel backbone, because such linkers can be cleaved by means of one‐ and two‐photon absorption. Herein we describe a cytocompatible click‐based hydrogel containing o‐nitrobenzyl ester linkages between a hyaluronic acid backbone, which is photodegradable in the presence of cells. It is demonstrated for the first time that by using a cyclic benzylidene ketone‐based small molecule as photosensitizer the efficiency of the two‐photon degradation process can be improved significantly. Biocompatibility of both the improved two‐photon micropatterning process as well as the hydrogel itself is confirmed by cell culture studies.
Sensitized micropatterning of photodegradable hydrogels by means of two‐photon irradiation is possible. The efficiency of the photoscission of o‐nitrobenzyl ester linkages is enhanced by the modular addition of a two‐photon active small molecule to a preformed hyaluronic acid based hydrogel. Biocompatibility of the improved two‐photon micropatterning process as well as the hydrogel is confirmed by cell culture studies.
The morphogenetic process of mammalian cardiac development is complex and highly regulated spatiotemporally by multipotent cardiac stem/progenitor cells (CPCs). Mouse studies have been informative ...for understanding mammalian cardiogenesis; however, similar insights have been poorly established in humans. Here, we report comprehensive gene expression profiles of human cardiac derivatives from multipotent CPCs to intermediates and mature cardiac cells by population and single-cell RNA-seq using human embryonic stem cell-derived and embryonic/fetal heart-derived cardiac cells micro-dissected from specific heart compartments. Importantly, we discover a uniquely human subset of cono-ventricular region-specific CPCs, marked by LGR5. At 4 to 5 weeks of fetal age, the LGR5+ population appears to emerge specifically in the proximal outflow tract of human embryonic hearts and thereafter promotes cardiac development and alignment through expansion of the ISL1+TNNT2+ intermediates. The current study contributes to a deeper understanding of human cardiogenesis, which may uncover the putative origins of certain human congenital cardiac malformations.
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•Comprehensive gene expression profiles on human cardiogenesis are reported•LGR5 is identified as a key regulator on human-specific cono-ventriculogenesis•LGR5 signaling may be associated with certain human congenital heart diseases
Sahara et al. performed population and single-cell transcriptional analysis of in vitro cardiac differentiation from human embryonic stem cells and human embryonic/fetal hearts. They identified human-specific cardiogenic programs driven by LGR5, which has an important role in cono-ventricular region development in human cardiogenesis.
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