Generation of three CRISPR/Cas9 edited human induced pluripotent stem cell lines (DHMi005-A-5, DHMi005-A-6 and DHMi005-A-7) carrying a Holt-Oram Syndrome patient-specific TBX5 mutation with known cardiac phenotype and a FLAG-tag after exon 9 of the TBX5 gene

TBX5 is a transcription factor (TF) playing essential role during cardiogenesis. It is well known that TF mutations possibly result in non- or additional binding of the DNA due to conformational changes of the protein. We introduced a Holt-Oram Syndrome (HOS) patient-specific TBX5 mutation c.920_C > A heterozygously in a healthy induced pluripotent stell cell (iPSC) line. This TBX5 mutation results in conformational changes of the protein and displayed ventricular septal defects in the patient itself. Additionally we introduced a FLAG-tag on the TBX5 mutation-carrying allele. The resulting heterozygous TBX5-FLAG iPSC lines are a powerful tool to investigate altered TF activity bonding.

Generation of two CRISPR/Cas edited human induced pluripotent stem cell lines (DHMi005-A-3 and DHMi005-A-4) carrying a FLAG-tag after exon 9 of the TBX5 gene

Although TBX5 plays a major role during human cardiogenesis and initiates and controls limb development, many of its interactions with genomic DNA and the resulting biological consequences are not well known. Existing anti-TBX5-antibodies work very inefficiently in certain applications such as ChIP-Seq analysis. To circumvent this drawback, we introduced a FLAG-tag sequence into the TBX5 locus at the end of exon 9 prior to the stop codon by CRISPR/Cas9. The expressed TBX5-FLAG fusion protein can effectively be precipitated by anti-FLAG antibodies. Therefore, these gene-edited iPSC lines represent powerful cellular in vitro tools to unravel TBX5:DNA interactions in detail.

Establishment of an induced pluripotent stem cell line DHMi005-A from a healthy male proband

We generated an induced pluripotent stem cell (iPSC) line from a healthy male 29-year-old proband. Adipose fibroblasts (AFs) were reprogrammed using Sendai virus. Generated iPSCs showed typical stem cell morphology. From passage 9 on, iPSCs were free of virus. Pluripotency in the iPSCs was verified and spontaneous differentiation showed expression of all three germ layers. Karyotyping indicated no anomalies for the generated iPSCs. Many patient-specific iPSCs are generated from subcutaneous fat fibroblasts obtained during surgical procedure. The described control iPSC line was generated equally and therefore serves as an ideal control for adipose-fibroblast-based patient-specific iPSC lines in disease modeling.

Establishment of a patient-specific induced pluripotent stem cell line DHMi004-A from a male Holt-Oram syndrome patient with verified TBX5 mutation

The Holt-Oram syndrome (HOS) is a rare autosomal dominant disorder, mostly based on mutations in the TBX5 gene. Patients show malformation of at least one upper limb along with congenital heart defects. The established induced pluripotent stem cell (iPSC) line was generated from a patient displaying pronounced and typical features of HOS and carrying a single-nucleotide change c.920_C>A leading to an amino acid change from proline to threonine at amino acid position 85, which appeared de novo. Adipose fibroblasts from the patient were reprogrammed using Sendai virus. Pluripotency of the iPSCs was fully demonstrated.

Human Engineered Heart Tissue Patches Remuscularize the Injured Heart in a Dose-Dependent Manner

Supplemental Digital Content is available in the text.

Human engineered heart tissue (EHT) transplantation represents a potential regenerative strategy for patients with heart failure and has been successful in preclinical models. Clinical application requires upscaling, adaptation to good manufacturing practices, and determination of the effective dose.

P913What can we expect after valve-in-valve procedures in failed transcatheter aortic valves?

Background/Purpose

With the growing use of transcatheter aortic valve replacement (TAVR), we need to determine if repeat TAVR (TAV-in-TAV) is comparable or even superior to surgical aortic valve replacement followed by TAVR (TAV-in-SAV). Although TAV-in-SAV procedures were shown to provide an almost complete sealing of paravalvular leakage at the expense of elevated gradients, data for TAV-in-TAV are lacking. Hence, we compared echocardiographic and clinical outcome in all TAV-in-TAV and TAV-in-SAV procedures in our institution between Oct. 2007 and July 2017.

Methods

130 consecutive valve-in-valve patients out of 2351 TAVR-patients were identified. 24 patients were excluded. Patient data were analysed from our prospectively collected, institutional database. 93% underwent routine out-patient follow-up at 12 months.

Results

75 TAV-in-SAV (75±8 years, male 60%; STS score 5.2±4.0%) and 31 TAV-in-TAV patients (78±8 years, male 65%; STS score 4.6±2.8%) formed the final study population. The type of TAV was similarly distributed in both groups (self-/balloon-expandable valves [%] 57/43 vs. 61/39) with transfemoral being the most frequent access site (68% vs. 87%). The mode of prosthesis failure was mainly stenosis in the TAV-in-SAV group (77%), whereas it was mainly intraoperative paravalvular regurgitation (90%) in the TAV-in-TAV group. 10% TAV-in-TAV patients (78±10 years, 33% male, STS score 5.1±1.5%) underwent redo-TAVR for prosthesis-degeneration after a mean time of 2614±862 days. The TAV-in-TAV group (90% single session vs. 10% staged: mean gradient 10±4 mmHg vs. 15±3 mmHg, p=0.096; aortic valve area 1.62±0.36 cm2 vs. 1.45±0.18 cm2, p=0.240) showed lower gradients and larger aortic valve areas (Table 1). No major intraprocedural complications occurred in either group. 30-day mortality was 0%.

Table 1 75 TAV-in-SAV discharge 31 TAV-in-TAV discharge p-value 69 TAV-in-SAV 12mFU 30 TAV-in-TAV 12mFU p-value AVA (cm2) * 1.18±0.32 1.61±0.35 <0.001† 1.21±0.36 1.63±0.43 <0.001† Peak Gradient (mmHg) 33±14 23±8 <0.001† 31±14 21±8 <0.001† Mean Gradient (mmHg) 19±8 12±5 <0.001† 18±9 11±4 <0.001† AR (0–3)** 0.4±0.5 0.8±0.7 0.003† 0.4±0.5 0.8±0.6 0.001† LV ejection fraction (%) 49±12 49±16 0.970 54±12 50±10 0.081 *AVA = Aortic valve area; **AR = Aortic regurgitation. 0 = none, 1 = mild, 2 = moderate, 3 = severe. †p<0,05 significant.

Conclusion

Indications for TAV-in-TAV differ from those for TAV-in-SAV. TAV-in-TAV results in significantly lower gradients and larger aortic valve areas with no relevant aortic regurgitation. Accordingly, failed TAV valves may be treated with TAV-in-TAV in the future.

Corpuls cpr resuscitation device generates superior emulated flows and pressures than LUCAS II in a mechanical thorax model

The provision of sufficient chest compression is among the most important factors influencing patient survival during cardiopulmonary resuscitation (CPR). One approach to optimize the quality of chest compressions is to use mechanical-resuscitation devices. The aim of this study was to compare a new device for chest compression (corpuls cpr) with an established device (LUCAS II). We used a mechanical thorax model consisting of a chest with variable stiffness and an integrated heart chamber which generated blood flow dependent on the compression depth and waveform. The method of blood-flow generation could be changed between direct cardiac-compression mode and thoracic-pump mode. Different chest-stiffness settings and compression modes were tested to generate various blood-flow profiles. Additionally, an endurance test at high stiffness was performed to measure overall performance and compression consistency. Both resuscitation machines were able to compress the model thorax with a frequency of 100/min and a depth of 5 cm, independent of the chosen chest stiffness. Both devices passed the endurance test without difficulty. The corpuls cpr device was able to generate about 10-40% more blood flow than the LUCAS II device, depending on the model settings. In most scenarios, the corpuls cpr device also generated a higher blood pressure than the LUCAS II. The peak compression forces during CPR were about 30% higher using the corpuls cpr device than with the LUCAS II. In this study, the corpuls cpr device had improved blood flow and pressure outcomes than the LUCAS II device. Further examination in an animal model is required to prove the findings of this preliminary study.

Long-term results after transcatheter aortic valve implantation: what do we know today?

Transcatheter aortic valve implantation (TAVI) is evolving rapidly as a therapeutic option in patients deemed to be at high risk for surgical aortic valve replacement. Early outcome and survival of controlled feasibility trials and single- center experience with TAVI have been previously reported. Valve performance and hemodynamics seem to improve significantly after TAVI. Long-term outcome up to 3 years have been demonstrated in recent studies. Admittedly, the results are encouraging with a survival rate at 2 and 3 years ranging from 62 to 74% and from 56 to 61% respectively. The improvement in hemodynamical and clinical status sustained beyond the 3 years follows up. However, paravalvular leakage after TAVI remains an important issue in this rapidely evolving field.