Non Thermal Irreversible Electroporation: Novel Technology for Vascular Smooth Muscle Cells Ablation

Non thermal Irreversible electroporation (NTIRE) is a new tissue ablation method that induces selective damage only to the cell membrane while sparing all other tissue components. Our group has recently showed that NTIRE attenuated neointimal formation in rodent model. The goal of this study was to determine optimal values of NTIRE for vascular smooth muscle cell (VSMC) ablation.33 Sprague-Dawley rats were used to compare NTIRE protocols. Each animal had NTIRE applied to its left common carotid artery using a custom-made electrodes. The right carotid artery was used as control. Electric pulses of 100 microseconds were used. Eight IRE protocols were compared: 1-4) 10 pulses at a frequency of 10 Hz with electric fields of 3500, 1750, 875 and 437.5 V/cm and 5-8) 45 and 90 pulses at a frequency of 1 Hz with electric fields of 1750 and 875 V/cm. Animals were euthanized after one week. Histological analysis included VSMC counting and morphometry of 152 sections. Selective slides were stained with elastic Van Gieson and Masson trichrome to evaluate extra-cellular structures. The most efficient protocols were 10 pulses of 3500 V/cm at a frequency of 10 Hz and 90 pulses of 1750 V/cm at a frequency of 1 Hz, with ablation efficiency of 89+/-16% and 94+/-9% respectively. Extra-cellular structures were not damaged and the endothelial layer recovered completely.NTIRE is a promising, efficient and simple novel technology for VMSC ablation. It enables ablation within seconds without causing damage to extra-cellular structures, thus preserving the arterial scaffold and enabling endothelial regeneration. This study provides scientific information for future anti-restenosis experiments utilizing NTIRE

BASILICA Trial: One-Year Outcomes of Transcatheter Electrosurgical Leaflet Laceration to Prevent TAVR Coronary Obstruction

Background: Coronary artery obstruction is a rare, devastating complication of transcatheter aortic valve replacement. Transcatheter electrosurgical aortic leaflet laceration (Bioprosthetic or Native Aortic Scallop Intentional Laceration to Prevent Iatrogenic Coronary Artery Obstruction [BASILICA]) is a novel technique to prevent coronary artery obstruction. We report the 1-year outcomes of the BASILICA trial. Primary end points of 30-day success and safety have been reported previously. Methods: The BASILICA trial was a prospective, multicenter, single-arm safety and feasibility study. Subjects with severe native or bioprosthetic aortic valve disease at high or extreme risk for surgery, and high risk of coronary artery obstruction, were included. End points at 1 year included death, stroke, and myocardial infarction. Source data was independently verified and end points independently adjudicated. Results: Thirty subjects were enrolled between February 2018 and July 2018. At 30 days, BASILICA was successful in 28 subjects (93.3%), there were 3 strokes (10%), including 1 disabling stroke (3.3%), 1 death (3.3%), and 1 periprocedural myocardial infarction (3.3%). Between 30 days and 1 year, there were no additional strokes, no myocardial infarction, and 2 deaths (10% 1-year mortality). No subject needed repeat intervention for aortic valve or coronary disease. Two subjects had infective endocarditis (6.7%), but neither was isolated to the aortic valve. There were no hospital admissions for heart failure. Fourteen (46.7%) subjects required repeat hospital admission for other causes. Aortic valve gradients on echocardiography, New York Heart Association functional class, and Kansas City Cardiomyopathy Questionnaire scores improved from baseline to 30 days and were maintained at 1 year. Conclusions: In these subjects with multiple comorbidities and restrictive anatomy that underwent transcatheter aortic valve replacement, there was no late stroke, myocardial infarction, or death related to BASILICA. Mitigation of coronary obstruction remained intact at 1 year and was not related to recurrent readmission. These results are reassuring for patients and physicians who wish to avoid the long-term complications related to snorkel stenting

Guillain-Barré syndrome: a century of progress

In 1916, Guillain, Barré and Strohl reported on two cases of acute flaccid paralysis with high cerebrospinal fluid protein levels and normal cell counts — novel findings that identified the disease we now know as Guillain–Barré syndrome (GBS). 100 years on, we have made great progress with the clinical and pathological characterization of GBS. Early clinicopathological and animal studies indicated that GBS was an immune-mediated demyelinating disorder, and that severe GBS could result in secondary axonal injury; the current treatments of plasma exchange and intravenous immunoglobulin, which were developed in the 1980s, are based on this premise. Subsequent work has, however, shown that primary axonal injury can be the underlying disease. The association of Campylobacter jejuni strains has led to confirmation that anti-ganglioside antibodies are pathogenic and that axonal GBS involves an antibody and complement-mediated disruption of nodes of Ranvier, neuromuscular junctions and other neuronal and glial membranes. Now, ongoing clinical trials of the complement inhibitor eculizumab are the first targeted immunotherapy in GBS

Edge restenosis: impact of low dose irradiation on cell proliferation and ICAM-1 expression

BACKGROUND: Low dose irradiation (LDI) of uninjured segments is the consequence of the suggestion of many authors to extend the irradiation area in vascular brachytherapy to minimize the edge effect. Atherosclerosis is a general disease and the uninjured segment close to the intervention area is often atherosclerotic as well, consisting of neointimal smooth muscle cells (SMC) and quiescent monocytes (MC). The current study imitates this complex situation in vitro and investigates the effect of LDI on proliferation of SMC and expression of intercellular adhesion molecule-1 (ICAM-1) in MC. METHODS: Plaque tissue from advanced primary stenosing lesions of human coronary arteries (9 patients, age: 61 ± 7 years) was extracted by local or extensive thrombendarterectomy. SMC were isolated and identified by positive reaction with smooth muscle α-actin. MC were isolated from buffy coat leukocytes using the MACS cell isolation kit. For identification of MC flow-cytometry analysis of FITC-conjugated CD68 and CD14 (FACScan) was applied. SMC and MC were irradiated using megavoltage photon irradiation (CLINAC2300 C/D, VARIAN, USA) of 6 mV at a focus-surface distance of 100 cm and a dose rate of 6 Gy min(-1 )with single doses of 1 Gy, 4 Gy, and 10 Gy. The effect on proliferation of SMC was analysed at day 10, 15, and 20. Secondly, total RNA of MC was isolated 1 h, 2 h, 3 h, and 4 h after irradiation and 5 μg of RNA was used in standard Northern blot analysis with ICAM-1 cDNA-probes. RESULTS: Both inhibitory and stimulatory effects were detected after irradiation of SMC with a dose of 1 Gy. At day 10 and 15 a significant antiproliferative effect was found; at day 20 after irradiation cell proliferation was significantly stimulated. Irradiation with 4 Gy and 10 Gy caused dose dependent inhibitory effects at day 10, 15, and 20. Expression of ICAM-1 in human MC was neihter inhibited nor stimulated by LDI. CONCLUSION: Thus, the stimulatory effect of LDI on SMC proliferation at day 20 days after irradiation may be the in vitro equivalent of a beginning edge effect. Extending the irradiation area in vascular brachytherapy in vivo may therefore merely postpone and not inhibit the edge effect. The data do not indicate that expression of ICAM-1 in quiescent MC is involved in the process

Structural Differences between the Streptococcus agalactiae Housekeeping and Pilus-Specific Sortases: SrtA and SrtC1

The assembly of pili on the cell wall of Gram-positive bacteria requires transpeptidase enzymes called sortases. In Streptococcus agalactiae, the PI-1 pilus island of strain 2603V/R encodes two pilus-specific sortases (SrtC1 and SrtC2) and three pilins (GBS80, GBS52 and GBS104). Although either pilus-specific sortase is sufficient for the polymerization of the major pilin, GBS80, incorporation of the minor pilins GBS52 and GBS104 into the pilus structure requires SrtC1 and SrtC2, respectively. The S. agalactiae housekeeping sortase, SrtA, whose gene is present at a different location and does not catalyze pilus polymerization, was shown to be involved in cell wall anchoring of pilus polymers. To understand the structural basis of sortases involved in such diverse functions, we determined the crystal structures of S. agalactiae SrtC1 and SrtA. Both enzymes are made of an eight-stranded beta-barrel core with variations in their active site architecture. SrtA exhibits a catalytic triad arrangement similar to that in Streptococcus pyogenes SrtA but different from that in Staphylococcus aureus SrtA. In contrast, the SrtC1 enzyme contains an N-terminal helical domain and a ‘lid’ in its putative active site, which is similar to that seen in Streptococcus pneumoniae pilus-specific sortases, although with subtle differences in positioning and composition. To understand the effect of such differences on substrate recognition, we have also determined the crystal structure of a SrtC1 mutant, in which the conserved DP(W/F/Y) motif was replaced with the sorting signal motif of GBS80, IPNTG. By comparing the structures of WT wild type SrtA and SrtC1 and the ‘lid’ mutant of SrtC1, we propose that structural elements within the active site and the lid may be important for defining the role of specific sortase in pili biogenesis

Prospective Evaluation of TMVR for Failed Surgical Annuloplasty Rings: MITRAL Trial Valve-in-Ring Arm 1-Year Outcomes

OBJECTIVES: The authors report 1-year outcomes of high-risk patients with failed surgical annuloplasty rings undergoing transseptal mitral valve-in-ring (MViR) with the SAPIEN 3 aortic transcatheter heart valve (THV). BACKGROUND: The MITRAL (Mitral Implantation of Transcatheter Valves) trial is the first prospective study evaluating transseptal MViR with the SAPIEN 3 aortic THV in high-risk patients with failed surgical annuloplasty rings. METHODS: Prospective enrollment of high-risk patients with symptomatic moderate to severe or severe mitral regurgitation (MR) or severe mitral stenosis and failed annuloplasty rings at 13 U.S. sites. The primary safety endpoint was technical success. The primary THV performance endpoint was absence of MR grade ≥2+ or mean mitral valve gradient ≥10 mm Hg (30 days and 1 year). Secondary endpoints included procedural success and all-cause mortality (30 days and 1 year). RESULTS: Thirty patients were enrolled between January 2016 and October 2017 (median age 71.5 years [interquartile range: 67.0 to 76.8 years], 36.7% women, median Society of Thoracic Surgeons score 7.6% [interquartile range: 5.1% to 11.8%], 76.7% in New York Heart Association functional class III or IV). Technical success was 66.7% (driven primarily by need for a second valve in 6 patients). There was no intraprocedural mortality or conversion to surgery. The primary performance endpoint was achieved in 85.7% of survivors at 30 days (24 of 28) and 89.5% of patients alive at 1 year with echocardiographic data available (17 of 19). All-cause mortality at 30 days was 6.7% and at 1 year was 23.3%. Among survivors at 1-year follow-up, 84.2% were in New York Heart Association functional class I or II, the median mean mitral valve gradient was 6.0 mm Hg (interquartile range: 4.7 to 7.3 mm Hg), and all had ≤1+ MR. CONCLUSIONS: Transseptal MViR was associated with a 30-day mortality rate lower than predicted by the Society of Thoracic Surgeons score. At 1 year, transseptal MViR was associated with symptom improvement and stable THV performance

Development of Grb2 SH2 Domain Signaling Antagonists: A Potential New Class of Antiproliferative Agents

Aberrant signaling through protein-tyrosine kinase (PTK)-dependent pathways is associated with several proliferative diseases. Accordingly, PTK inhibitors are being developed as new approaches for the treatment of certain cancers. Growth factor receptor bound protein 2 (Grb2) is an important downstream mediator of PTK signaling that serves obligatory roles in many pathogenic processes. One of the primary functions of Grb2 is to bind to specific phosphotyrosyl (pTyr)-containing sequences through its Src homology 2 (SH2) domain. Agents that bind to the Grb2 SH2 domain and prevent its normal function could disrupt associated PTK signaling and serve as alternatives to kinase-directed inhibitors. Starting from the X-ray crystal structure of a lead peptide bound to the Grb2 SH2 domain, this review will summarize important contributions to these efforts. The presentation will be thematically arranged according to the region of peptide modified, proceeding from the N-terminus to the C-terminus, with a special section devoted to aspects of conformational constraint