A defined clathrin-mediated trafficking pathway regulates sFLT1/VEGFR1 secretion from endothelial cells.

FLT1/VEGFR1 negatively regulates VEGF-A signaling and is required for proper vessel morphogenesis during vascular development and vessel homeostasis. Although a soluble isoform, sFLT1, is often mis-regulated in disease and aging, how sFLT1 is trafficked and secreted from endothelial cells is not well understood. Here we define requirements for constitutive sFLT1 trafficking and secretion in endothelial cells from the Golgi to the plasma membrane, and we show that sFLT1 secretion requires clathrin at or near the Golgi. Perturbations that affect sFLT1 trafficking blunted endothelial cell secretion and promoted intracellular mis-localization in cells and zebrafish embryos. siRNA-mediated depletion of specific trafficking components revealed requirements for RAB27A, VAMP3, and STX3 for post-Golgi vesicle trafficking and sFLT1 secretion, while STX6, ARF1, and AP1 were required at the Golgi. Live-imaging of temporally controlled sFLT1 release from the endoplasmic reticulum showed clathrin-dependent sFLT1 trafficking at the Golgi into secretory vesicles that then trafficked to the plasma membrane. Depletion of STX6 altered vessel sprouting in 3D, suggesting that endothelial cell sFLT1 secretion influences proper vessel sprouting. Thus, specific trafficking components provide a secretory path from the Golgi to the plasma membrane for sFLT1 in endothelial cells that utilizes a specialized clathrin-dependent intermediate, suggesting novel therapeutic targets.

Implant-to-implant wireless networking with metamaterial textiles.

Implanted bioelectronic devices can form distributed networks capable of sensing health conditions and delivering therapy throughout the body. Current clinically-used approaches for wireless communication, however, do not support direct networking between implants because of signal losses from absorption and reflection by the body. As a result, existing examples of such networks rely on an external relay device that needs to be periodically recharged and constitutes a single point of failure. Here, we demonstrate direct implant-to-implant wireless networking at the scale of the human body using metamaterial textiles. The textiles facilitate non-radiative propagation of radio-frequency signals along the surface of the body, passively amplifying the received signal strength by more than three orders of magnitude (>30 dB) compared to without the textile. Using a porcine model, we demonstrate closed-loop control of the heart rate by wirelessly networking a loop recorder and a vagus nerve stimulator at more than 40 cm distance. Our work establishes a wireless technology to directly network body-integrated devices for precise and adaptive bioelectronic therapies.

A defined clathrin-mediated trafficking pathway regulates sFLT1/VEGFR1 secretion from endothelial cells.

FLT1/VEGFR1 negatively regulates VEGF-A signaling and is required for proper vessel morphogenesis during vascular development and vessel homeostasis. Although a soluble isoform, sFLT1, is often mis-regulated in disease and aging, how sFLT1 is trafficked and secreted from endothelial cells is not well understood. Here we define requirements for constitutive sFLT1 trafficking and secretion in endothelial cells from the Golgi to the plasma membrane, and we show that sFLT1 secretion requires clathrin at or near the Golgi. Perturbations that affect sFLT1 trafficking blunted endothelial cell secretion and promoted intracellular mis-localization in cells and zebrafish embryos. siRNA-mediated depletion of specific trafficking components revealed requirements for RAB27A, VAMP3, and STX3 for post-Golgi vesicle trafficking and sFLT1 secretion, while STX6, ARF1, and AP1 were required at the Golgi. Depletion of STX6 altered vessel sprouting in a 3D angiogenesis model, indicating that endothelial cell sFLT1 secretion is important for proper vessel sprouting. Thus, specific trafficking components provide a secretory path from the Golgi to the plasma membrane for sFLT1 in endothelial cells that utilizes a specialized clathrin-dependent intermediate, suggesting novel therapeutic targets.

Needle-integrated ultrathin bioimpedance microsensor array for early detection of extravasation.

Extravasation is a common complication during intravenous therapy in which infused fluids leak into the surrounding tissues. Timely intervention can prevent severe adverse consequences, but early detection remains an unmet clinical need because existing sensors are not sensitive to leakage occurring in small volumes (< 200 µL) or at deep venipuncture sites. Here, an ultrathin bioimpedance microsensor array that can be integrated on intravenous needles for early and sensitive detection of extravasation is reported. The array comprises eight microelectrodes fabricated on an ultrathin and flexible polyimide substrate as well as functionalized using poly(3,4-ethylenedioxythiophene) and multi-walled carbon nanotubes. Needle integration places the array proximity to venipuncture site, and functional coating significantly reduces interface impedance, both enable the microsensors with high sensitivity to detect early extravasation. In vitro and in vivo experiments demonstrate the capability of the microsensors to differentiate various intravenous solutions from different tissue layers as well as identify saline extravasation with detection limit as low as 20 µL.

Wirelessly operated bioelectronic sutures for the monitoring of deep surgical wounds.

Monitoring surgical wounds post-operatively is necessary to prevent infection, dehiscence and other complications. However, the monitoring of deep surgical sites is typically limited to indirect observations or to costly radiological investigations that often fail to detect complications before they become severe. Bioelectronic sensors could provide accurate and continuous monitoring from within the body, but the form factors of existing devices are not amenable to integration with sensitive wound tissues and to wireless data transmission. Here we show that multifilament surgical sutures functionalized with a conductive polymer and incorporating pledgets with capacitive sensors operated via radiofrequency identification can be used to monitor physicochemical states of deep surgical sites. We show in live pigs that the sutures can monitor wound integrity, gastric leakage and tissue micromotions, and in rodents that the healing outcomes are equivalent to those of medical-grade sutures. Battery-free wirelessly operated bioelectronic sutures may facilitate post-surgical monitoring in a wide range of interventions.

Safety, pharmacokinetics and tissue penetration of PIPAC paclitaxel in a swine model.

INTRODUCTION: Peritoneal carcinomatosis is difficult to treat. Pressurized Intra-Peritoneal Aerosolised Chemotherapy (PIPAC) is a novel method of delivering chemotherapy to the peritoneal cavity, aiming for homogenous and deeper drug distribution. To date, limited chemotherapeutics have been used with promising results. Here, we evaluate the pharmacokinetics, peritoneal tissue drug concentration, penetration, and short-term safety of PIPAC using solvent-based paclitaxel in swine to guide clinical trials. MATERIALS AND METHODS: PIPAC solvent-based paclitaxel was administered at 60, 30, and 15mg/m2 for 3 cohorts. Each PIPAC procedure was followed by intravenous (IV) administration of the same dose of solvent-based paclitaxel on Day 7, serving as control for pharmacokinetic comparison in the same pig. Safety and toxicity were evaluated by clinical assessment, blood counts and biochemistry. Blood samples were taken for pharmacokinetic analysis. Peritoneal biopsies were taken to measure tissue paclitaxel concentrations and distribution. RESULTS: 12 Yorkshire x Landrace pigs underwent trial procedures. With PIPAC, there was linear pharmacokinetics and lower systemic exposure to paclitaxel compared to IV administration. MALDI-MSI demonstrated concentration of paclitaxel at the peritoneal surface, with estimated 2 mm penetration. PIPAC paclitaxel had favorable toxicity profile. The most significant adverse event was neutropenia which was dose dependent, with absolute neutrophil count <1.0 × 103/µL seen at the highest dose. One pig developed grade 2 hypersensitivity reaction during IV infusion and one death occurred during the PIPAC procedure, likely from anaphylaxis; these are known potential adverse events mandating standard precautions and monitoring. CONCLUSION: PIPAC paclitaxel at 15mg/m2 may be considered for a Phase I study.

Systemic Mesenchymal Stem Cell-Derived Exosomes Reduce Myocardial Infarct Size: Characterization With MRI in a Porcine Model.

The observations that mesenchymal stem cells (MSCs) exert cardiac protection and repair via their secretome with the active component(s) identified as exosomes underpinned our test of the efficacy of MSC exosomes in a porcine model of myocardial infarction (MI) when administered systemically by the convenient method of intravenous (IV) bolus injection. Results show that 7 days of IV exosomes results in clear reduction (30-40%) of infarct size measured at both 7 and 28 days post-MI, despite near identical release of hs Troponin T. Together with reduced infarct size, exosome treatment reduced transmurality and lessened wall thinning in the infarct zone. Exosome treated pigs showed relative preservation of LV function with significant amelioration of falls in fractional wall thickening compared with control. However, global measures of LV function were less protected by exosome treatment. It is possible that greater preservation of global LV function may have been attenuated by increased cardiac fibrosis, as T1 values showed significant increase in the exosome pigs compared to control particularly in the infarct related segments. Taken together, these results show clear effects of IV exosomes administered over 7 days to reduce infarct size with relatively preserved cardiac function compared to control treated infarct pigs.

Measurement of the Luminal Diameter of Peripheral Arterial Vasculature in Yorkshire×Landrace Swine by Using Ultrasonography and Angiography.

To select animals of appropriate size for preclinical studies of cardiovascular devices, reference knowledge of the cardiovascularanatomy relative to body weight is crucial. We measured the luminal diameters of the arteries (carotid, femoral, and iliac arteries) that are the common access vessels for endovascular and vascular procedures in Yorkshire×Landrace swine. Measurements were performed by using both ultrasound and angiographic methods and were correlated with body weight. Results showed no statistically significant difference between the left and right vessels in the diameters of the carotid,femoral, and iliac arteries. The diameters of the measured arteries showed high correlation with animal weight in pigs thatweighed less than 70 kg.

A porcine model of heart failure with preserved ejection fraction: magnetic resonance imaging and metabolic energetics.

AIMS: A significant proportion of heart failure (HF) patients have HF preserved ejection fraction (HFpEF). The lack of effective treatments for HFpEF remains a critical unmet need. A key obstacle to therapeutic innovation in HFpEF is the paucity of pre-clinical models. Although several large animal models have been reported, few demonstrate progression to decompensated HF. We have established a model of HFpEF by enhancing a porcine model of progressive left ventricular (LV) pressure overload and characterized HF in this model including advanced cardiometabolic imaging using cardiac magnetic resonance imaging and hyperpolarized carbon-13 magnetic resonance spectroscopy. METHODS AND RESULTS: Pigs underwent progressive LV pressure overload by means of an inflatable aortic cuff. Pigs developed LV hypertrophy (50% increase in wall thickness, P < 0.001, and two-fold increase in mass compared to sham control, P < 0.001) with no evidence of LV dilatation but a significant increase in left atrial volume (P = 0.013). Cardiac magnetic resonance imaging demonstrated T1 modified Look-Locker inversion recovery values increased in 16/17 segments compared to sham pigs (P < 0.05-P < 0.001) indicating global ventricular fibrosis. Mean LV end-diastolic (P = 0.047) and pulmonary capillary wedge pressures (P = 0.008) were elevated compared with sham control. One-third of the pigs demonstrated clinical signs of frank decompensated HF, and mean plasma BNP concentrations were raised compared with sham control (P = 0.008). Cardiometabolic imaging with hyperpolarized carbon-13 magnetic resonance spectroscopy agreed with known metabolic changes in the failing heart with a switch from fatty acid towards glucose substrate utilization. CONCLUSIONS: Progressive aortic constriction in growing pigs induces significant LV hypertrophy with cardiac fibrosis associated with left atrial dilation, raised filling pressures, and an ability to transition to overt HF with raised BNP without reduction in LVEF. This model replicates many aspects of clinical HFpEF with a predominant background of hypertension and can be used to advance understanding of underlying pathology and for necessary pre-clinical testing of novel candidate therapies.