Gas-propelled nanomotors alleviate colitis through the regulation of intestinal immunoenvironment-hematopexis-microbiota circuits.

The progression of ulcerative colitis (UC) is associated with immunologic derangement, intestinal hemorrhage, and microbiota imbalance. While traditional medications mainly focus on mitigating inflammation, it remains challenging to address multiple symptoms. Here, a versatile gas-propelled nanomotor was constructed by mild fusion of post-ultrasonic CaO2 nanospheres with Cu2O nanoblocks. The resulting CaO2-Cu2O possessed a desirable diameter (291.3 nm) and a uniform size distribution. It could be efficiently internalized by colonic epithelial cells and macrophages, scavenge intracellular reactive oxygen/nitrogen species, and alleviate immune reactions by pro-polarizing macrophages to the anti-inflammatory M2 phenotype. This nanomotor was found to penetrate through the mucus barrier and accumulate in the colitis mucosa due to the driving force of the generated oxygen bubbles. Rectal administration of CaO2-Cu2O could stanch the bleeding, repair the disrupted colonic epithelial layer, and reduce the inflammatory responses through its interaction with the genes relevant to blood coagulation, anti-oxidation, wound healing, and anti-inflammation. Impressively, it restored intestinal microbiota balance by elevating the proportions of beneficial bacteria (e.g., Odoribacter and Bifidobacterium) and decreasing the abundances of harmful bacteria (e.g., Prevotellaceae and Helicobacter). Our gas-driven CaO2-Cu2O offers a promising therapeutic platform for robust treatment of UC via the rectal route.

Hyperoxia impairs induced pluripotent stem cell-derived endothelial cells and drives an atherosclerosis-like transcriptional phenotype.

Background: Induced pluripotent stem cells (iPSCs) directed to endothelial identity (iPSC-ECs) are emerging as a potent tool for regenerative medicine in vascular disease. However, iPSC-ECs lose expression of key identity markers under standard in vitro conditions, limiting their clinical applications. Methods: To model physiological in vivo conditions, we examined the bioenergetics, presence of key cell markers, and proliferative and angiogenic capacity in iPSC-ECs at late and early passage under hyperoxic (21%) and physiological (4%) oxygen concentrations. Results: Physoxia resulted in relative preservation of mitochondrial bioenergetic activity, as well as CD144 expression in late passage iPSC-ECs, but not proliferative capacity or tube formation. Single cell RNA sequencing (scRNA-seq) revealed that late passage hyperoxic iPSC-ECs develop an endothelial-to-mesenchymal phenotype. Comparing scRNA-seq data from iPSC-ECs and from atherosclerotic ECs revealed overlap of their transcriptional phenotypes. Conclusions: Taken together, our studies demonstrate that physiological 4% oxygen culture conditions were sufficient to improve mitochondrial function in high passage cells, but alone was insufficient to preserve angiogenic capacity. Furthermore, late passage cells under typical conditions take on an endothelial-to-mesenchymal phenotype with similarities to ECs found in atherosclerosis.

High-resolution volumetric imaging constrains compartmental models to explore synaptic integration and temporal processing by cochlear nucleus globular bushy cells.

Globular bushy cells (GBCs) of the cochlear nucleus play central roles in the temporal processing of sound. Despite investigation over many decades, fundamental questions remain about their dendrite structure, afferent innervation, and integration of synaptic inputs. Here, we use volume electron microscopy (EM) of the mouse cochlear nucleus to construct synaptic maps that precisely specify convergence ratios and synaptic weights for auditory nerve innervation and accurate surface areas of all postsynaptic compartments. Detailed biophysically based compartmental models can help develop hypotheses regarding how GBCs integrate inputs to yield their recorded responses to sound. We established a pipeline to export a precise reconstruction of auditory nerve axons and their endbulb terminals together with high-resolution dendrite, soma, and axon reconstructions into biophysically detailed compartmental models that could be activated by a standard cochlear transduction model. With these constraints, the models predict auditory nerve input profiles whereby all endbulbs onto a GBC are subthreshold (coincidence detection mode), or one or two inputs are suprathreshold (mixed mode). The models also predict the relative importance of dendrite geometry, soma size, and axon initial segment length in setting action potential threshold and generating heterogeneity in sound-evoked responses, and thereby propose mechanisms by which GBCs may homeostatically adjust their excitability. Volume EM also reveals new dendritic structures and dendrites that lack innervation. This framework defines a pathway from subcellular morphology to synaptic connectivity, and facilitates investigation into the roles of specific cellular features in sound encoding. We also clarify the need for new experimental measurements to provide missing cellular parameters, and predict responses to sound for further in vivo studies, thereby serving as a template for investigation of other neuron classes.

Nicotine exacerbates atherosclerosis and plaque instability via NLRP3 inflammasome activation in vascular smooth muscle cells.

Rationale: Nicotine has been reported to be a strong risk factor for atherosclerosis. However, the underlying mechanism by which nicotine controls atherosclerotic plaque stability remain largely unknown. Objective: The aim of this study was to evaluate the impact of lysosomal dysfunction mediated NLRP3 inflammasome activation in vascular smooth muscle cell (VSMC) on atherosclerotic plaque formation and stability in advanced atherosclerosis at the brachiocephalic arteries (BA). Methods and Results: Features of atherosclerotic plaque stability and the markers for NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome were monitored in the BA from nicotine or vehicle-treated apolipoprotein E deficient (Apoe-/-) mice fed with Western-type diet (WD). Nicotine treatment for 6 weeks accelerated atherosclerotic plaque formation and enhanced the hallmarks of plaque instability in BA of Apoe-/- mice. Moreover, nicotine elevated interleukin 1 beta (IL-1ß) in serum and aorta and was preferred to activate NLRP3 inflammasome in aortic vascular smooth muscle cells (VSMC). Importantly, pharmacological inhibition of Caspase1, a key downstream target of NLRP3 inflammasome complex, and genetic inactivation of NLRP3 significantly restrained nicotine-elevated IL-1ß in serum and aorta, as well as nicotine-stimulated atherosclerotic plaque formation and plaque destabilization in BA. We further confirmed the role of VSMC-derived NLRP3 inflammasome in nicotine-induced plaque instability by using VSMC specific TXNIP (upstream regulator of NLRP3 inflammasome) deletion mice. Mechanistic study further showed that nicotine induced lysosomal dysfunction resulted in cathepsin B cytoplasmic release. Inhibition or knockdown of cathepsin B blocked nicotine-dependent inflammasome activation. Conclusions: Nicotine promotes atherosclerotic plaque instability by lysosomal dysfunction-mediated NLRP3 inflammasome activation in vascular smooth muscle cells.

Human ApoE2 Endows Stronger Contractility in Rat Cardiomyocytes Enhancing Heart Function.

(1) Background: Apolipoprotein E (ApoE) is a critical plasma apolipoprotein for lipid transport and nonlipid-related functions. Humans possess three isoforms of ApoE (2, 3, and 4). ApoE2, which exhibits beneficial effects on cardiac health, has not been adequately studied. (2) Methods: We investigated the cardiac phenotypes of the humanized ApoE knock-in (hApoE KI) rats and compared to wild-type (WT) and ApoE knock-out (ApoE KO) rats using echocardiography, ultrasound, blood pressure measurements, histology strategies, cell culture, Seahorse XF, cardiomyocyte contractility and intracellular Ca2+ tests, and Western blotting; (3) Results: hApoE2 rats exhibited enhanced heart contractile function without signs of detrimental remodeling. Isolated adult hApoE2 cardiomyocytes had faster and stronger sarcomere contractility because of more mitochondrial energy generation and stimulation-induced fast and elevated intracellular Ca2+ transient. The abundant energy is a result of elevated mitochondrial function via fatty acid ß-oxidation. The fast and elevated Ca2+ transient is associated with decreased sarcoplasmic reticulum (SR) Ca2+ ATPase (SERCA2) and increased expression of cardiac ryanodine receptor 2 (RyR2) conducting a potent Ca2+ release from SR.; (4) Conclusions: Our studies validated the association of polymorphic ApoEs with cardiac health in the rat model, and revealed the possible mechanisms of the protective effect of ApoE2 against heart diseases.

Real-time feedback control of split-belt ratio to induce targeted step length asymmetry.

INTRODUCTION: Split-belt treadmill training has been used to assist with gait rehabilitation following stroke. This method modifies a patient's step length asymmetry by adjusting left and right tread speeds individually during training. However, current split-belt training approaches pay little attention to the individuality of patients by applying set tread speed ratios (e.g., 2:1 or 3:1). This generalization results in unpredictable step length adjustments between the legs. To customize the training, this study explores the capabilities of a live feedback system that modulates split-belt tread speeds based on real-time step length asymmetry. MATERIALS AND METHODS: Fourteen healthy individuals participated in two 1.5-h gait training sessions scheduled 1 week apart. They were asked to walk on the Computer Assisted Rehabilitation Environment (CAREN) split-belt treadmill system with a boot on one foot to impose asymmetrical gait patterns. Each training session consisted of a 3-min baseline, 10-min baseline with boot, 10-min feedback with boot (6% asymmetry exaggeration in the first session and personalized in the second), 5-min post feedback with boot, and 3-min post feedback without boot. A proportional-integral (PI) controller was used to maintain a specified step-length asymmetry by changing the tread speed ratios during the 10-min feedback period. After the first session, a linear model between baseline asymmetry exaggeration and post-intervention asymmetry improvement was utilized to develop a relationship between target exaggeration and target post-intervention asymmetry. In the second session, this model predicted a necessary target asymmetry exaggeration to replace the original 6%. This prediction was intended to result in a highly symmetric post-intervention step length. RESULTS AND DISCUSSION: Eleven out of 14 participants (78.6%) developed a successful relationship between asymmetry exaggeration and decreased asymmetry in the post-intervention period of the first session. Seven out of the 11 participants (63.6%) in this successful correlation group had second session post-intervention asymmetries of < 3.5%. CONCLUSIONS: The use of a PI controller to modulate split-belt tread speeds demonstrated itself to be a viable method for individualizing split-belt treadmill training.

Metabolic Synergy between Human Symbionts Bacteroides and Methanobrevibacter.

Trophic interactions between microbes are postulated to determine whether a host microbiome is healthy or causes predisposition to disease. Two abundant taxa, the Gram-negative heterotrophic bacterium Bacteroides thetaiotaomicron and the methanogenic archaeon Methanobrevibacter smithii, are proposed to have a synergistic metabolic relationship. Both organisms play vital roles in human gut health; B. thetaiotaomicron assists the host by fermenting dietary polysaccharides, whereas M. smithii consumes end-stage fermentation products and is hypothesized to relieve feedback inhibition of upstream microbes such as B. thetaiotaomicron. To study their metabolic interactions, we defined and optimized a coculture system and used software testing techniques to analyze growth under a range of conditions representing the nutrient environment of the host. We verify that B. thetaiotaomicron fermentation products are sufficient for M. smithii growth and that accumulation of fermentation products alters secretion of metabolites by B. thetaiotaomicron to benefit M. smithii. Studies suggest that B. thetaiotaomicron metabolic efficiency is greater in the absence of fermentation products or in the presence of M. smithii. Under certain conditions, B. thetaiotaomicron and M. smithii form interspecies granules consistent with behavior observed for syntrophic partnerships between microbes in soil or sediment enrichments and anaerobic digesters. Furthermore, when vitamin B12, hematin, and hydrogen gas are abundant, coculture growth is greater than the sum of growth observed for monocultures, suggesting that both organisms benefit from a synergistic mutual metabolic relationship. IMPORTANCE The human gut functions through a complex system of interactions between the host human tissue and the microbes which inhabit it. These diverse interactions are difficult to model or examine under controlled laboratory conditions. We studied the interactions between two dominant human gut microbes, B. thetaiotaomicron and M. smithii, using a seven-component culturing approach that allows the systematic examination of the metabolic complexity of this binary microbial system. By combining high-throughput methods with machine learning techniques, we were able to investigate the interactions between two dominant genera of the gut microbiome in a wide variety of environmental conditions. Our approach can be broadly applied to studying microbial interactions and may be extended to evaluate and curate computational metabolic models. The software tools developed for this study are available as user-friendly tutorials in the Department of Energy KBase.

Insights into the biotechnology potential of Methanosarcina.

Methanogens are anaerobic archaea which conserve energy by producing methane. Found in nearly every anaerobic environment on earth, methanogens serve important roles in ecology as key organisms of the global carbon cycle, and in industry as a source of renewable biofuels. Environmentally, methanogenic archaea play an essential role in the reintroducing unavailable carbon to the carbon cycle by anaerobically converting low-energy, terminal metabolic degradation products such as one and two-carbon molecules into methane which then returns to the aerobic portion of the carbon cycle. In industry, methanogens are commonly used as an inexpensive source of renewable biofuels as well as serving as a vital component in the treatment of wastewater though this is only the tip of the iceberg with respect to their metabolic potential. In this review we will discuss how the efficient central metabolism of methanoarchaea could be harnessed for future biotechnology applications.

Anaerobic Production of Isoprene by Engineered Methanosarcina Species Archaea.

Isoprene is a valuable petrochemical used for a wide variety of consumer goods, such as adhesives and synthetic rubber. We were able to achieve a high yield of renewable isoprene by taking advantage of the naturally high-flux mevalonate lipid synthesis pathway in anaerobic methane-producing archaea (methanogens). Our study illustrates that by genetically manipulating Methanosarcina species methanogens, it is possible to create organisms that grow by producing the hemiterpene isoprene. Mass balance measurements show that engineered methanogens direct up to 4% of total carbon flux to isoprene, demonstrating that methanogens produce higher isoprene yields than engineered yeast, bacteria, or cyanobacteria, and from inexpensive feedstocks. Expression of isoprene synthase resulted in increased biomass and changes in gene expression that indicate that isoprene synthesis depletes membrane precursors and redirects electron flux, enabling isoprene to be a major metabolic product. Our results demonstrate that methanogens are a promising engineering chassis for renewable isoprene synthesis.IMPORTANCE A significant barrier to implementing renewable chemical technologies is high production costs relative to those for petroleum-derived products. Existing technologies using engineered organisms have difficulty competing with petroleum-derived chemicals due to the cost of feedstocks (such as glucose), product extraction, and purification. The hemiterpene monomer isoprene is one such chemical that cannot currently be produced using cost-competitive renewable biotechnologies. To reduce the cost of renewable isoprene, we have engineered methanogens to synthesize it from inexpensive feedstocks such as methane, methanol, acetate, and carbon dioxide. The "isoprenogen" strains we developed have potential to be used for industrial production of inexpensive renewable isoprene.

Metabolic Feedback Inhibition Influences Metabolite Secretion by the Human Gut Symbiont Bacteroides thetaiotaomicron.

Microbial metabolism and trophic interactions between microbes give rise to complex multispecies communities in microbe-host systems. Bacteroides thetaiotaomicron (B. theta) is a human gut symbiont thought to play an important role in maintaining host health. Untargeted nuclear magnetic resonance metabolomics revealed B. theta secretes specific organic acids and amino acids in defined minimal medium. Physiological concentrations of acetate and formate found in the human intestinal tract were shown to cause dose-dependent changes in secretion of metabolites known to play roles in host nutrition and pathogenesis. While secretion fluxes varied, biomass yield was unchanged, suggesting feedback inhibition does not affect metabolic bioenergetics but instead redirects carbon and energy to CO2 and H2 Flux balance analysis modeling showed increased flux through CO2-producing reactions under glucose-limiting growth conditions. The metabolic dynamics observed for B. theta, a keystone symbiont organism, underscores the need for metabolic modeling to complement genomic predictions of microbial metabolism to infer mechanisms of microbe-microbe and microbe-host interactions.IMPORTANCE Bacteroides is a highly abundant taxon in the human gut, and Bacteroides thetaiotaomicron (B. theta) is a ubiquitous human symbiont that colonizes the host early in development and persists throughout its life span. The phenotypic plasticity of keystone organisms such as B. theta is important to understand in order to predict phenotype(s) and metabolic interactions under changing nutrient conditions such as those that occur in complex gut communities. Our study shows B. theta prioritizes energy conservation and suppresses secretion of "overflow metabolites" such as organic acids and amino acids when concentrations of acetate are high. Secreted metabolites, especially amino acids, can be a source of nutrients or signals for the host or other microbes in the community. Our study suggests that when metabolically stressed by acetate, B. theta stops sharing with its ecological partners.

Can Patients With COPD Assimilate Disease-Specific Information During an Acute Exacerbation?: Results of a Pilot Randomized Controlled Trial.

BACKGROUND: The study aimed to determine the feasibility and effectiveness of an introductory disease-specific educational program delivered during an acute exacerbation of COPD (AECOPD) on objective measures of disease-specific knowledge. METHODS: Patients admitted to a community hospital with an AECOPD were randomly assigned to a control group (standard care) or intervention group (standard care + brief education). The intervention group received two 30-min education sessions in hospital or at home within 2 weeks of hospital admission. Feasibility measures included the number of eligible patients, compliance with the sessions, and number of follow-up measures completed. Disease-specific knowledge and informational needs were measured using the Bristol COPD Knowledge Questionnaire (BCKQ) and the Lung Information Needs Questionnaire (LINQ), respectively, before and after the intervention period. RESULTS: Thirty-one patients (mean age, 72 ± 10 years) with an AECOPD participated in the study. Of 102 approached patients, 75 consented to screening (73.5%) and 67 (66%) were eligible for the study. Thirty-four patients declined participation. All intervention patients (n = 15) completed the educational sessions and follow-up measures. Three patients (control group) did not complete the follow-up measures. The mean changes and SDs for the BCKQ in the intervention and control groups were 8 ± 5.14 and 3.4 ± 4.9, respectively (P = .02). No difference between groups was found for the LINQ (P = .80). CONCLUSIONS: A brief educational program delivered at the time of hospitalization for an AECOPD was feasible for a subset of patients, resulted in improved disease-specific knowledge, and may be a bridge to more active approaches. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT02321215; URL: www.clinicaltrials.gov.

Biliary Stenosis and Gastric Outlet Obstruction: Late Complications After Acute Pancreatitis With Pancreatic Duct Disruption.

OBJECTIVES: Pancreatic duct disruption (PDD) after acute pancreatitis can cause pancreatic collections in the early phase and biliary stenosis (BS) or gastric outlet obstruction (GOO) in the late phase. We aimed to document those late complications after moderate or severe acute pancreatitis. METHODS: Between September 2010 and August 2014, 141 patients showed pancreatic collections on computed tomography. Percutaneous drainage was primarily performed for patients with signs or symptoms of uncontrolled pancreatic juice leakage. Pancreatic duct disruption was defined as persistent amylase-rich drain fluid or a pancreatic duct cut-off on imaging. Clinical course of the patients who developed BS or GOO was investigated. RESULTS: Among the 141 patients with collections, 33 patients showed PDD in the pancreatic head/neck area. Among them, 9 patients (27%) developed BS 65 days after onset and required stenting for 150 days, and 5 patients (15%) developed GOO 92 days after onset and required gastric decompression and jejunal tube feeding for 147 days (days shown in median). All 33 patients recovered successfully without requiring surgical intervention. CONCLUSIONS: Anatomic proximity of the bile duct or duodenum to the site of PDD and severe inflammation seemed to contribute to the late onset of BS or GOO. Conservative management successfully reversed these complications.

Better Outcomes if Percutaneous Drainage Is Used Early and Proactively in the Course of Necrotizing Pancreatitis.

PURPOSE: To compare outcomes after percutaneous catheter drainage (PCD) for acute necrotizing pancreatitis versus those in a randomized controlled trial as a reference standard. MATERIALS AND METHODS: Between September 2010 and August 2014, CT-guided PCD was the primary treatment for 39 consecutive patients with pancreatic necrosis. The indication for PCD was the clinical finding of uncontrolled pancreatic juice leakage rather than infected necrosis. Subsequent to PCD, the drains were proactively studied with fluoroscopic contrast medium every 3 days to ensure patency and position. Drains were ultimately maneuvered to the site of leakage. These 39 patients were compared with 43 patients from the Pancreatitis, Necrosectomy versus Step-up Approach (PANTER) trial. RESULTS: The CT severity index was similar between studies (median of 8 in each). Time from onset of acute pancreatitis to PCD was shorter in the present series (median, 23 d vs 30 d). The total number of procedures (PCD and subsequent fluoroscopic drain studies) per patient was greater in the present series (mean, 14 vs 2). More patients in the PANTER trial had organ failure (62% vs 84%), required open or endoscopic necrosectomy (0% vs 60%), and experienced in-hospital mortality (0% vs 19%; P < .05 for all). CONCLUSIONS: Even though patients in the present series had a similar CT severity index as those in the PANTER trial, the former group showed lower incidences of organ failure, need for necrosectomy, and in-hospital mortality. The use of a proactive PCD protocol early, before the development of severe sepsis, appeared to be effective.

A percutaneous drainage protocol for severe and moderately severe acute pancreatitis.

BACKGROUND: According to the revised Atlanta classification, severe and moderately severe acute pancreatitis (AP) includes patients with pancreatic and peripancreatic collections with or without organ failure. These collections suggest the presence of pancreatic juice leakage. The aim of this study was to evaluate the efficacy of a percutaneous catheter drainage (PCD) protocol designed to control leakage and decrease disease severity. METHODS: Among 663 patients with clinical AP, 122 were classified as moderately severe or severe AP (all had collections). The computed tomography severity index (CTSI) score was calculated. The indication for PCD was based on progressive clinical signs and symptoms. Drain patency, position, and need for additional drainage sites were assessed using CT scans and drain studies initially every 3 days using a proactive protocol. Drain fluid was examined for amylase concentration and microbiological culture. Clinicopathological variables for patients with and without PCD were compared. Since there was no mortality, we used prolonged drainage time to measure the success of PCD. Within the group treated with PCD, variables that resulted in prolonged drainage time were analyzed. RESULTS: PCD was used in 47/122 (39 %) patients of which 33/47 (70 %) had necrosis. PCD cases had a median CTSI of 8 and were classified as moderately severe AP (57 %) and severe AP (43 %). Inhospital mortality was zero. Surgical necrosectomy was not required for patients with necrosis. Independent risk factors for prolonged drainage time were persistent organ failure >48 h (P = 0.001), CTSI 8-10 (P = 0.038), prolonged duration of amylase-rich fluid in drains (P < 0.001), and polymicrobial culture fluid in drains (P = 0.015). CONCLUSIONS: A proactive PCD protocol persistently maintaining drain patency advanced to the site of leak controlled the prolonged amylase in drainage fluid resulting in a mortality rate of zero.