Biocompatibility of an apical ring plug for left ventricular assist device explantation: Results of a feasibility pre-clinical study

Unraveling the link between neuropathy target esterase NTE/SWS, lysosomal storage diseases, inflammation, abnormal fatty acid metabolism, and leaky brain barrier

Mutations in Drosophila Swiss cheese (SWS) gene or its vertebrate orthologue neuropathy target esterase (NTE) lead to progressive neuronal degeneration in flies and humans. Despite its enzymatic function as a phospholipase is well established, the molecular mechanism responsible for maintaining nervous system integrity remains unclear. In this study, we found that NTE/SWS is present in surface glia that forms the blood-brain barrier (BBB) and that NTE/SWS is important to maintain its structure and permeability. Importantly, BBB glia-specific expression of Drosophila NTE/SWS or human NTE in the sws mutant background fully rescues surface glial organization and partially restores BBB integrity, suggesting a conserved function of NTE/SWS. Interestingly, sws mutant glia showed abnormal organization of plasma membrane domains and tight junction rafts accompanied by the accumulation of lipid droplets, lysosomes, and multilamellar bodies. Since the observed cellular phenotypes closely resemble the characteristics described in a group of metabolic disorders known as lysosomal storage diseases (LSDs), our data established a novel connection between NTE/SWS and these conditions. We found that mutants with defective BBB exhibit elevated levels of fatty acids, which are precursors of eicosanoids and are involved in the inflammatory response. Also, as a consequence of a permeable BBB, several innate immunity factors are upregulated in an age-dependent manner, while BBB glia-specific expression of NTE/SWS normalizes inflammatory response. Treatment with anti-inflammatory agents prevents the abnormal architecture of the BBB, suggesting that inflammation contributes to the maintenance of a healthy brain barrier. Considering the link between a malfunctioning BBB and various neurodegenerative diseases, gaining a deeper understanding of the molecular mechanisms causing inflammation due to a defective BBB could help to promote the use of anti-inflammatory therapies for age-related neurodegeneration.

Ciliary Ultrastructure Assessed by Transmission Electron Microscopy in Adults with Bronchiectasis and Suspected Primary Ciliary Dyskinesia but Inconclusive Genotype

Whole-exome sequencing has expedited the diagnostic work-up of primary ciliary dyskinesia (PCD), when used in addition to clinical phenotype and nasal nitric oxide. However, it reveals variants of uncertain significance (VUS) in established PCD genes or (likely) pathogenic variants in genes of uncertain significance in approximately 30% of tested individuals. We aimed to assess genotype-phenotype correlations in adults with bronchiectasis, clinical suspicion of PCD, and inconclusive whole-exome sequencing results using transmission electron microscopy (TEM) and ciliary image averaging by the PCD Detect software. We recruited 16 patients with VUS in CCDC39, CCDC40, CCDC103, DNAH5, DNAH5/CCDC40, DNAH8/HYDIN, DNAH11, and DNAI1 as well as variants in the PCD candidate genes DNAH1, DNAH7, NEK10, and NME5. We found normal ciliary ultrastructure in eight patients with VUS in CCDC39, DNAH1, DNAH7, DNAH8/HYDIN, DNAH11, and DNAI1. In six patients with VUS in CCDC40, CCDC103, DNAH5, and DNAI1, we identified a corresponding ultrastructural hallmark defect. In one patient with homozygous variant in NME5, we detected a central complex defect supporting clinical relevance. Using TEM as a targeted approach, we established important genotype-phenotype correlations and definite PCD in a considerable proportion of patients. Overall, the PCD Detect software proved feasible in support of TEM.

Endothelial Cell Behavior and Nitric Oxide Production on a-C:H:SiOx-Coated Ti-6Al-4V Substrate

This paper focuses on the surface modification of the Ti-6Al-4V alloy substrate via a-C:H:SiOx coating deposition. Research results concern the a-C:H:SiOx coating structure, investigated using transmission electron microscopy and in vitro endothelization to study the coating. Based on the analysis of the atomic radial distribution function, a model is proposed for the atomic short-range order structure of the a-C:H:SiOx coating, and chemical bonds (C–O, C–C, Si–C, Si–O, and Si–Si) are identified. It is shown that the a-C:H:SiOx coating does not possess prolonged cytotoxicity in relation to EA.hy926 endothelial cells. In vitro investigations showed that the adhesion, cell number, and nitric oxide production by EA.hy926 endothelial cells on the a-C:H:SiOx-coated Ti-6Al-4V substrate are significantly lower than those on the uncoated surface. The findings suggest that the a-C:H:SiOx coating can reduce the risk of endothelial cell hyperproliferation on implants and medical devices, including mechanical prosthetic heart valves, endovascular stents, and mechanical circulatory support devices.

Novel Plug Device for HeartMate 3 Explantation: First Multicenter Experience

Patients undergoing explantation of left ventricular assist devices (LVADs) after improvement of myocardial function remain a minority. Nevertheless, considering the growing population of LVAD patients, increasing demand for new explantation strategies is expected. Herein, we present a retrospective review of seven patients undergoing HeartMate3 explantation with the use of a custom-made apical ring plug in four medical centers. The primary outcome was status at intensive care unit discharge. Secondary outcomes included perioperative complications and transfusions. Six out of seven patients were males. The median age at explantation and time on LVAD support was 35 years (range:13-73) and 10 months (range:9-24), respectively. No technical difficulties were experienced during plug implantation via a conventional sternotomy or through a left lateral thoracotomy, either with or without cardiopulmonary bypass. Perioperative transfusions ranged from 0 to 3 units/patient. No re-operations for bleeding, hemorrhagic, embolic, or plug-related infective events were observed. Heparin was started 6 hours after surgery as a bridge to oral anticoagulation (international normalized ratio: 2-2.5). All patients were discharged alive from intensive care unit. This novel plug device for HeartMate3 explantation was successfully and safely implanted in this first patient series. Notwithstanding, its use should still be considered off-label and larger studies are required to investigate its long-term results.

Outcome of percutaneous HeartMate3 decommissioning: A single-centre experience

OBJECTIVES

To highlight the role of percutaneous left ventricular assist device (LVAD) decommissioning as a safe procedure after myocardial recovery in patients with advanced heart failure.

BACKGROUND

The HeartMate3 LVAD (Abbott, Chicago, IL, USA) is designed to provide circulatory support with enhanced hemocompatibility for patients with advanced heart failure. Most VADs are used as a bridge to heart transplantation; however, in certain cases, myocardial function recovers, and VADs can be explanted after the patient is weaned. Although surgical explantation remains the gold standard, minimally invasive percutaneous decommissioning has been described as a successful alternative. In this study, we present our experience, one-year outcomes, and adverse events associated with percutaneous LVAD decommissioning.

METHODS

We conducted a retrospective review of data from six consecutive patients who underwent percutaneous LVAD decommissioning.

RESULTS

Six patients were enrolled in the study. For all six patients, HM3 decommissioning was completed at least 6 months ago. No technical complications were documented. No strokes were observed within the study period, and the ejection fraction improved. The mean follow-up duration was 18 ± 8.5 months, and the survival rate was 100%.

CONCLUSION

Percutaneous HeartMate3 decommissioning appears to be safe. In particular, the survival after the procedure was 100%, and no events, especially thromboembolic ones, occurred.