Human neuromuscular junction on micro-structured microfluidic devices implemented with a custom micro electrode array (MEA).

In the neuromuscular system, signal transmission from motor neurons (MNs) to innervated muscle fibers is crucial for their synaptic function, viability, and maintenance. In order to better understand human neuromuscular junction (hNMJ) functionality, it is important to develop on-a-chip devices with human cells. To investigate this cell network, microfluidic platforms are useful to grow different cell types in isolated compartments. Such devices have already been developed to study in vitro neuronal circuitry. Here, we combined microfluidics with two techniques: soft lithography and custom microelectrodes array (MEA). Our goal was to create hNMJs on a specific pattern of electrodes to stimulate pre-synaptic axons and record post-synaptic muscle activity. Micromachining was used to create structurations to guide muscle growth above electrodes, without impairing axon propagation, therefore optimizing the effectiveness of activity recording. Electrodes were also arranged to be aligned with the microfluidic chambers in order to specifically stimulate axons that were growing between the two compartments. Isolation of the two cell types allows for the selective treatment of neurons or muscle fibers to assess NMJ functionality hallmarks. Altogether, this microfluidic/microstructured/MEA platform allowed mature and functional in vitro hNMJ modelling. We demonstrate that electrical activation of MNs can trigger recordable extracellular muscle action potentials. This study provides evidence for a physiologically relevant model to mimic a hNMJ that will in the future be a powerful tool, more sensitive than calcium imaging, to better understand and characterize NMJs and their disruption in neurodegenerative diseases.

Midterm Outcomes of Gastric Pouch Resizing for Weight Regain After Roux-en-Y Gastric Bypass.

PURPOSE: Resizing of the gastric pouch, with eventually resizing of the gastrojejunal anastomosis, has been proposed as revisional procedure to treat weight regain after Roux-en-Y gastric bypass (RYGB), in patients with large gastric pouch and/or large gastrojejunal (GJ) anastomosis. The aim of this study is to determine the midterm results and the safety of laparoscopic resizing of the gastric pouch after RYGB in cases where gastric pouch is > 200 ml and/or GJ anastomosis > 20 mm. MATERIALS AND METHODS: All patients who underwent gastric pouch resizing between January 2009 and December 2016 were retrospectively reviewed from a prospective database. The gastric pouch was resized to a volume of 30-40 ml. RESULTS: A total of 48 patients had gastric pouch resizing after RYGB. The mean initial BMI was 42.9 ± 4.8 kg/m2. Perioperative morbidity was 8.3% in this series. Mean follow-up was 5.4 years. The mean BMI was 30.0 ± 7.3 kg/m2 at 1 year, 30.0 ± 6.0 kg/m2 at 3 years, and 30.9 ± 5.7 kg/m2 at 5 years. Mean %EBMIL at 1-, 3-, and 5-year follow-up was 51.9%, 55.1%, and 39%, respectively, in 48% follow-up rate. The obesity-related comorbidities disappeared in 67.3% of cases at maximum follow-up. CONCLUSIONS: In carefully selected patients with gastric pouch size > 200 ml and/or GJ anastomosis > 20 mm, and after extensive preoperative evaluation, gastric pouch resizing is a potentially effective option to treat weight regain due to anatomical factors after RYGB, with complication rate of 8%.

Discrepant effects of inducible nitric oxide synthase modulation on systemic and splanchnic endothelial nitric oxide synthase activity and expression in cirrhotic rats.

BACKGROUND: Arterial vasodilatation, which is a major factor in the pathogenesis of the hyperkinetic circulatory state and portal hypertension in cirrhosis, is due to arterial nitric oxide (NO) overproduction secondary to endothelial NO synthase (eNOS) and inducible NOS (iNOS) upregulation. However, in cirrhosis, the respective roles of eNOS and iNOS isoforms in NO overproduction are still unknown and the effect of iNOS modulation on eNOS activity and expression has not been evaluated in the systemic or splanchnic vessels. The aim of this study was to evaluate the effects of modulating aortic and superior mesenteric arteries (SMA) iNOS on arterial eNOS activity and expression in rats with cirrhosis. METHODS: eNOS and iNOS protein expression and eNOS activity (assessed by its phosphorylation at serine 1177) were measured in the aortas and SMA in untreated and treated cirrhotic rats with lipopolysaccharide (LPS), N-iminoethyl-L-lysine (L-NIL), a selective iNOS inhibitor, and LPS plus L-NIL. RESULTS: LPS administration significantly increased eNOS and iNOS protein expression and eNOS activity in the aortas of both sham-operated and cirrhotic rats. However, in SMA, LPS administration induced a decrease in eNOS protein expression and activity and an increase in iNOS protein expression. CONCLUSION: The results of this study may explain the worsening of the hyperdynamic state in cirrhosis during septic shock by direct LPS-induced eNOS activation in large systemic vessels, and its inhibition in concomitant small splanchnic vasculature by iNOS synthesized NO.