Bioinspired micro/nanomotor with visible light energy-dependent forward, reverse, reciprocating, and spinning schooling motion.

In nature, microorganisms could sense the intensity of the incident visible light and exhibit bidirectional (positive or negative) phototaxis. However, it is still challenging to achieve the similar biomimetic phototaxis for the artificial micro/nanomotor (MNM) counterparts with the size from a few nanometers to a few micrometers. In this work, we report a fuel-free carbon nitride (C3N4)/polypyrrole nanoparticle (PPyNP)-based smart MNM operating in water, whose behavior resembles that of the phototactic microorganism. The MNM moves toward the visible light source under low illumination and away from it under high irradiation, which relies on the competitive interplay between the light-induced self-diffusiophoresis and self-thermophoresis mechanisms concurrently integrated into the MNM. Interestingly, the competition between these two mechanisms leads to a collective bidirectional phototaxis of an ensemble of MNMs under uniform illuminations and a spinning schooling behavior under a nonuniform light, both of which can be finely controllable by visible light energy. Our results provide important insights into the design of the artificial counterpart of the phototactic microorganism with sophisticated motion behaviors for diverse applications.

Genome-wide transcriptome and translatome analyses reveal the role of protein extension and domestication in liver cancer oncogenesis.

One gene could be transcribed to different RNA isoforms, and then produce various forms of protein sequences. This mechanism largely diversifies the cellular pool and allows natural selection to select from a wider range of substrates. In the cancer field, the isoform switches between tumor and normal tissues, such as the alternative splicing, stop codon read-through, or protein domestication, are significantly ignored by the traditional differential expression analyses. The intention of this work is to fill this gap. We collected public transcriptome and translatome data from ten patients with liver cancer, and performed genome-wide comparison on the stop codon read-through and protein domestication events. Both events diversify the proteome during long-term evolution. Surprisingly, we found that the tumor tissues globally have higher occurrence of stop codon read-through events as well as protein domestication events (translation signals of non-coding repetitive elements). These read-through and domestication events show limited overlapping across the ten patients, indicating the randomness of their occurrence and their deleterious nature. These tumor-specific events might have been purged by natural selection if they are not collected timely. Our work manifests the role of protein extension and domestication in liver cancer oncogenesis, adding new aspects to the cancer field.

Visible-Light-Driven Water-Fueled Ecofriendly Micromotors Based on Iron Phthalocyanine for Highly Efficient Organic Pollutant Degradation.

The light-driven micromotor has been demonstrated to have great potential in the environmental remediation field. However, it is still challenging to develop highly efficient, ecofriendly, and visible-light-powered micromotors for organic pollutant degradation. In this paper, we report an ecofriendly micromotor based on iron phthalocyanine (FePc) and gelatin, which exhibits the visible-light-driven self-propulsion behavior using water fuel based on the photocatalytic reaction and self-diffusiophoresis mechanism. Fast motion behavior is observed which induces the rapid agitation of the solution. This, together with the excellent photocatalytic activity, makes the FePc-based micromotor highly efficient when utilized in the degradation of organic pollutants with a normalized reaction rate constant of 2.49 × 10-2 L m-2 s-1, which is by far the fastest and is far superior than the stationary counterpart. The external fuel-free propulsion and the high efficiency in pollutant degradation make the current micromotor potentially attractive for environmental remediation.

Aberrant Notch signalling contributes to hypertrophic scar formation by modulating the phenotype of keratinocytes.

Hypertrophic scar (HS) is characterized by fibroblast hyperproliferation and excessive matrix deposition. Aberrant keratinocyte differentiation and their abnormal cytokine secretion are said to contribute to HS by activating fibroblasts. However, the signalling pathway causing the aberrant keratinocytes in HS has remained unidentified thus far. Given that Notch signalling is crucial in initiating keratinocyte differentiation, we hypothesized that Notch signalling contributes to HS by modulating the phenotype of keratinocytes. We found that Notch1, Notch intracellular domain, Jagged1 and Hes-1 were overexpressed in the epidermis of patients with HS. Supernatants from recombinant-Jagged1-treated keratinocyte cultures could accelerate dermal fibroblast proliferation and collagen production. Furthermore, Jagged1 induced keratinocyte differentiation and upregulated the expression of fibrotic factors, including transforming growth factors ß1 and ß2 , insulin-like growth factor-1, connective tissue growth factor, vascular endothelial growth factor and epidermal growth factor, while DAPT (a Notch inhibitor) significantly suppressed these processes. In a rabbit ear model of HS, local application of DAPT downregulated the production of fibrotic factors in keratinocytes, together with ameliorated scar hyperplasia. Our findings suggest that Notch signalling contributes to HS by modulating keratinocyte phenotype. These results provide new insights into the pathogenesis of HS and indicate a potential therapeutic target.

COMP-Ang1 promotes long-term survival of allogeneic islet grafts in a bioinert perforated chamber by inhibiting inflammation via inhibition of the TLR4 signaling pathway.

OBJECTIVES: To evaluate the effects of cartilage oligomeric matrix protein (COMP)- angiopoietin-1 (Ang1) on allogeneic islet graft survival in a bioinert perforated chamber. RESULTS: COMP-Ang1 treatment significantly decreased lipopolysaccharide-induced cell apoptosis and islet-related lymph node cell proliferation (both P < 0.01). Tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6 levels in the chamber exudate were significantly lower in the COMP-Ang1 + chamber group than in the chamber group (all P < 0.05), as were the protein expression levels. COMP-Ang1 significantly inhibited the expression of Toll-like receptor 4 (TLR4) in cultured islets. Finally, full COMP-Ang1 treatment resulted in the longest survival time among the treatment groups. CONCLUSION: Combined use of the bioinert perforated chamber with COMP-Ang1 is an effective strategy for improving islet allograft survival.

Shape-Controlled Fabrication of the Polymer-Based Micromotor Based on the Polydimethylsiloxane Template.

We report the utilization of the polydimethylsiloxane template to construct polymer-based autonomous micromotors with various structures. Solid or hollow micromotors, which consist of polycaprolactone and platinum nanoparticles, can be obtained with controllable sizes and shapes. The resulting micromotor can not only be self-propelled in solution based on the bubble propulsion mechanism in the presence of the hydrogen peroxide fuel, but also exhibit structure-dependent motion behavior. In addition, the micromotors can exhibit various functions, ranging from fluorescence, magnetic control to cargo transportation. Since the current method can be extended to a variety of organic and inorganic materials, we thus believe it may have great potential in the fabrication of different functional micromotors for diverse applications.

Comparative study on fatigue evaluation of suspenders by introducing actual vehicle trajectory data.

Suspenders play a crucial role in transmitting loads from the bridge deck to the main cable in a suspension bridge. They are susceptible to fatigue due to repeated dynamic loads, particularly traffic loads. Traffic Load Models (TLMs), typically created using Monte-Carlo simulation and Weigh-In-Motion (WIM) data, are employed to evaluate this fatigue. However, these models often overlook practical vehicle trajectories and spatio-temporal distribution, which compromises the precision of fatigue assessments. In this study, we introduce a novel 2D Intelligent Driver Model (2D-IDM) that incorporates actual vehicle trajectories, with a particular focus on transverse vehicle movement. This enhancement aims to improve the fidelity of existing TLMs. To provide a clear, qualitative, and quantitative understanding of the effects of fatigue evaluation with or without actual trajectory characteristics, we have structured this paper as a comparative study. We compare our proposed model, denoted as TLM S-3, with two observation-based models (O-1 and O-2) and two simulation-based models (S-1 and S-2). We conducted an experimental case study on a long-span suspension bridge, where the actual traffic load trajectory was obtained using a WIM-Vision integrated system. To calculate fatigue damage considering both longitudinal and transverse directions, we established a multi-scale Finite Element Model (FEM) using solid element types to simulate the bridge girder. This model can generate the stress influence surface of the bridge and has been verified in both static and dynamic aspects. Our detailed comparative analysis demonstrates the consistency of the proposed 2D-IDM with the actual measured traffic load trajectories. This indicates that our approach can enhance the fidelity and precision of fatigue evaluations for bridge suspenders.

Cysteine-modulated colorimetric sensing of extracellular Mg2+ in rat brain based on the strong chelation interaction between dithiothreitol and Mg2+.

Simple and effective measurement of Mg(2+) in the brain of living animals is of great physiological and pathological importance. In this study, we report a facile yet highly selective colorimetric method for effective sensing of cerebral Mg(2+). The method is based on rational design of surface chemistry of gold nanoparticles (Au-NPs) with functional molecules including 1,4-dithiothreitol (DTT) and cysteine, enabling the fine tuning of the surface chemistry of Au-NPs in such a way that the addition of Mg(2+) into the Au-NPs dispersion could selectively trigger the change of the dispersion/aggregation states of Au-NPs. The strong chelation interaction between Mg(2+) and the hydroxyls in 1,4-dithiothreitol and the co-existence of cysteine on the surface of Au-NPs could, on one hand, enable the selective colorimetric detection of Mg(2+) and, on the other hand, avoid the aggregation of Au-NPs induced by DTT itself. As a result, the addition of Mg(2+) into the dispersion of the Au-NPs containing both cysteine and DTT results in the changes in both the color and the UV-vis spectra of the Au-NPs dispersion. The signal readout shows a linear relationship of Mg(2+) within the concentration range from 1 µM to 40 µM with a detection limit of 800 nM (S/N = 3). Moreover, the assay demonstrated here is free from the interference of some physiological species commonly existing in rat brain. Although Ca(2+) could interfere with the detection of Mg(2+) because of its strong chelation with DTT, it could be selectively masked by masking agent (i.e., ethyleneglcol-bis (2-aminoethylether) tetraacetic acid). By combining the microdialysis technique, the basal dialysate level of Mg(2+) is determined to be 299.2 ± 41.1 µM (n = 3) in the cerebral systems. The method essentially offers a new method for the detection of Mg(2+) in the cerebral system.

Online ascorbate sensing reveals oxidative injury occurrence in inferior colliculus in salicylate-induced tinnitus animal model.

Tinnitus is a widespread and serious clinical and social problem. Although oxidative injury has been suggested to be one of pathological mechanisms in auditory cortex, whether this mechanism could be applied to inferior colliculus remains unclear. In this study, we used an online electrochemical system (OECS) integrating in vivo microdialysis with selective electrochemical detector to continuously monitor the dynamics of ascorbate efflux, an index of oxidative injury, in inferior colliculus of living rats during sodium salicylate-induced tinnitus. We found that OECS with a carbon nanotubes (CNTs)-modified electrode as the detector selectively responses to ascorbate, which is free from the interference from sodium salicylate and MK-801 that were used to induce tinnitus animal model and investigate the N-methyl-d-aspartate (NMDA) receptor mediated excitotoxicity, respectively. With the OECS, we found that the extracellular ascorbate level in inferior colliculus significantly increases after salicylate administration and such increase was suppressed by immediate injection of NMDA receptor antagonist MK-801. In addition, we found that salicylate administration significantly increases the spontaneous and sound stimuli evoked neural activity in inferior colliculus and that the increases were inhibited by the injection of MK-801. These results suggest that oxidative injury may occur in inferior colliculus following salicylate-induced tinnitus, which is closely relevant to the NMDA-mediated neuronal excitotoxicity. This information is useful for understanding the neurochemical processes in inferior colliculus involved in tinnitus and its related brain diseases.

Bioinspired rotary flight of light-driven composite films.

Light-driven actuators have great potential in different types of applications. However, it is still challenging to apply them in flying devices owing to their slow response, small deflection and force output and low frequency response. Herein, inspired by the structure of vine maple seeds, we report a helicopter-like rotary flying photoactuator (in response to 0.6 W/cm2 near-infrared (NIR) light) with ultrafast rotation (~7200 revolutions per minute) and rapid response (~650 ms). This photoactuator is operated based on a fundamentally different mechanism that depends on the synergistic interactions between the photothermal graphene and the hygroscopic agar/silk fibroin components, the subsequent aerodynamically favorable airscrew formation, the jet propulsion, and the aerodynamics-based flying. The soft helicopter-like photoactuator exhibits controlled flight and steering behaviors, making it promising for applications in soft robotics and other miniature devices.

Aspartic acid-promoted highly selective and sensitive colorimetric sensing of cysteine in rat brain.

Direct selective determination of cysteine in the cerebral system is of great importance because of the crucial roles of cysteine in physiological and pathological processes. In this study, we report a sensitive and selective colorimetric assay for cysteine in the rat brain with gold nanoparticles (Au-NPs) as the signal readout. Initially, Au-NPs synthesized with citrate as the stabilizer are red in color and exhibit absorption at 520 nm. The addition of an aqueous solution (20 µL) of cysteine or aspartic acid alone to a 200 µL Au-NP dispersion causes no aggregation, while the addition of an aqueous solution of cysteine into a Au-NP dispersion containing aspartic acid (1.8 mM) causes the aggregation of Au-NPs and thus results in the color change of the colloid from wine red to blue. These changes are ascribed to the ion pair interaction between aspartic acid and cysteine on the interface between Au-NPs and solution. The concentration of cysteine can be visualized with the naked eye and determined by UV-vis spectroscopy. The signal output shows a linear relationship for cysteine within the concentration range from 0.166 to 1.67 µM with a detection limit of 100 nM. The assay demonstrated here is highly selective and is free from the interference of other natural amino acids and other thiol-containing species as well as the species commonly existing in the brain such as lactate, ascorbic acid, and glucose. The basal dialysate level of cysteine in the microdialysate from the striatum of adult male Sprague-Dawley rats is determined to be around 9.6 ± 2.1 µM. The method demonstrated here is facile but reliable and durable and is envisaged to be applicable to understanding the chemical essence involved in physiological and pathological events associated with cysteine.

Strong interaction between imidazolium-based polycationic polymer and ferricyanide: toward redox potential regulation for selective in vivo electrochemical measurements.

This study effectively demonstrates a strategy to enable the ferricyanide-based second-generation biosensors for selective in vivo measurements of neurochemicals, with glucose as an example. The strategy is based on regulation of redox potential of ferricyanide mediator by carefully controlling the different adsorption ability of ferricyanide (Fe(CN)(6)(3-)) and ferrocyanide (Fe(CN)(6)(4-)) onto electrode surface. To realize the negative shift of the redox potential of Fe(CN)(6)(3-/4-), imidazolium-based polymer (Pim) is synthesized and used as a matrix for surface adsorption of Fe(CN)(6)(3-/4-) due to its stronger interaction with Fe(CN)(6)(3-) than with Fe(CN)(6)(4-). The different adsorption ability of Fe(CN)(6)(3-) and Fe(CN)(6)(4-) onto electrodes modified with a composite of Pim and multiwalled carbon nanotubes (MWNTs) eventually enables the stable surface adsorption of both species to generate integrated biosensors and, more importantly, leads to a negative shift of the redox potential of the surface-confined redox mediator. Using glucose oxidase (GOD) as the model biorecognition units, we demonstrate the validity of the ferricyanide-based second-generation biosensors for selective in vivo neurochemical measurements. We find that the biosensors developed with the strategy demonstrated in this study can be used well as the selective detector for continuous online detection of striatum glucose of guinea pigs, by integration with in vivo microdialysis. This study essentially paves a new avenue to developing electrochemical biosensors effectively for in vivo neurochemical measurements, which is envisaged to be of great importance in understanding the molecular basis of physiological and pathological events.

Modulatory effect of subthalamic nucleus on the development of fatigue during exhausting exercise: an in vivo electrophysiological and microdialysis study in rats.

The purpose of the study was to investigate the modulatory effect of changes of subthalamic nucleus (STN) activity on the development of central fatigue during exhausting exercise, and reveal the possible mechanism that might affect STN activity from the perspective of neurotransmitters. Rats were randomly divided into electrophysiology and microdialysis study groups. For electrophysiological study, electrical activity in sensorimotor cortex and STN were simultaneously recorded before, during and 90min after the exhausting exercise. For microdialysis study, extracellular fluid of STN was continuously collected with a microdialysis probe and glutamate (Glu), gamma-aminobutyric acid (GABA) levels were subsequently detected with high performance liquid chromatography (HPLC). The behavioral studies showed that rats ran well initiatively with the treadmill exercise in the beginning, 45 ± 11.5min later, movement capacity reduced obviously (which was termed as 'early fatigue'). Correspondingly, STN activity increased significantly compared with rest condition (p < 0.05), while, cortex activity decreased significantly (p < 0.05). Subsequently, rats continued their exercise with minor external stimulation till exhaustion. Cortex activity reached the minimum value under exhaustion condition, while STN activity changed insignificantly (p > 0.05). For microdialysis study, the dynamic change of Glu/GABA ratio was consistent with the change of STN activity during the development of 'early fatigue' rather than the development of exhaustion. In conclusion, the present study shows that, the development of the cortex fatigue during exhausting exercise consists of two phases, 'early fatigue' and exhaustion. Our results suggest that, dynamic changes of STN activity are closely relevant to the development of 'early fatigue' rather than exhaustion, and the changes of STN activity during the development of 'early fatigue' might be partly related to the variance of Glu and GABA levels in STN extracellular fluid. Key pointsThe development of the cortex fatigue during exhausting exercise consists of two phases, 'early fatigue' and exhaustion.Dynamic changes of STN activity are closely relevant to the development of 'early fatigue' rather than exhaustion.The changes of STN activity during the development of 'early fatigue' might be partly related to the variance of Glu and GABA levels in STN extracellular fluid.

Construction of Game Model between Carbon Emission Minimization and Energy and Resource Economy Maximization Based on Deep Neural Network.

Under this background, this paper tries to find countermeasures and ways for carbon reduction by observing and analyzing the influencing factors of carbon emissions, designing ways to minimize carbon emissions and maximize resources and energy. In view of the above problems, the carbon emission prediction research is closely combined with the research of deep neural network, the carbon emission prediction models based on deep neural network are established, respectively, and the game theory is introduced to maximize the resource economy. Based on the analysis of the cost of energy resources, this paper puts forward a model based on game theory and makes an overall planning of the bidding online auxiliary decision-making system in combination with the actual market demand. Build a big data analysis platform based on the Internet of things, collect the data related to carbon emission for normalization, analyze the influencing factors related to carbon emission by using the principal component analysis method, select the data with higher connection value, and take the time series data as the input of the deep neural network for simulation verification. The simulation results show that the game model of carbon emission minimization and energy resource economic maximization based on deep neural network can effectively improve the economic maximization of energy resources and reduce carbon emissions.

Research on Image Segmentation Algorithm Based on Multimodal Hierarchical Attention Mechanism and Genetic Neural Network.

Multimodal tasks based on attention mechanism and language face numerous problems. Based on multimodal hierarchical attention mechanism and genetic neural network, this paper studies the application of image segmentation algorithm in data completion and 3D scene reconstruction. The algorithm refers to the process of concentrating attention that humans subjectively pay attention to and calculates the difference between each pixel in the genetic neural network test image in the color space and the average value of the target image, which solves the problem of static feature maps and dynamic feature maps of image sequences. In addition, in view of the problem that the number of attention enhancement feature extraction modules is too large and the parameters are too large, the recursive mechanism is used as the feature extraction branch, and new model parameters are not added when the network depth is increased. The simulation results show that the accuracy of the improved image saliency detection algorithm based on the attention mechanism reaches 89.7%, and the difference between the average value of the single-point pixel and the target image is reduced to 0.132, which further promotes the practicability and reliability of the image segmentation model.

A Retrospective Statistical Validation Approach for Panel of Normal-Based Single-Nucleotide Variant Detection in Tumor Sequencing.

An important step of somatic variant calling algorithms for deep sequencing data is quantifying the errors. For targeted sequencing in which hotspot mutations are of interest, site-specific error estimation allows more accurate calling. The site-specific error rates are often estimated from a panel of normal samples, which has limited size and is subject to sampling bias and variance. We propose a novel statistical validation method for single-nucleotide variation (SNV) calling based on historical data. The validation method extracts the high-quality reads from the Binary Alignment/Map (BAM) files, finds the negative samples in the data, and builds a statistical model to call individual samples. It is particularly useful in detecting low-frequency variants that may be missed by traditional panel of normal-based SNV methods. The proposed method makes it possible to launch a simple and parallel validation pipeline for SNV calling and improve the detection limit.

Plasma-based microsatellite instability detection strategy to guide immune checkpoint blockade treatment.

BACKGROUND: Microsatellite instability (MSI) represents the first pan-cancer biomarker approved to guide immune checkpoint blockade (ICB) treatment. However its widespread testing, especially outside of gastrointestinal cancer, is hampered by tissue availability. METHODS: An algorithm for detecting MSI from peripheral blood was established and validated using clinical plasma samples. Its value for predicting ICB efficacy was evaluated among 60 patients with advanced gastrointestinal cancer. The landscape of MSI in blood was also explored among 5138 advanced solid tumors. RESULTS: The algorithm included 100 microsatellite markers with high capture efficiency, sensitivity, and specificity. In comparison with orthogonal tissue PCR results, the method displayed a sensitivity of 82.5% (33/40) and a specificity of 96.2% (201/209), for an overall accuracy of 94.0% (234/249). When the clinical validation cohort was dichotomized by pretreatment blood MSI (bMSI), bMSI-high (bMSI-H) predicted both improved progression-free survival and overall survival than the blood microsatellite stable (bMSS) patients (HRs: 0.431 and 0.489, p=0.005 and 0.034, respectively). Four patients with bMSS were identified to have high blood tumor mutational burden (bTMB-H) and trended towards a better survival than the bMSS-bTMB-low (bTMB-L) subset (HR 0.026, 95% CI 0 to 2.635, p=0.011). These four patients with bMSS-bTMB-H plus the bMSI-H group collectively displayed significantly improved survival over the bMSS-bTMB-L patients (HR 0.317, 95% CI 0.157 to 0.640, p<0.001). Pan-cancer prevalence of bMSI-H was largely consistent with that shown for tissue except for much lower rates in endometrial and gastrointestinal cancers, and a remarkably higher prevalence in prostate cancer relative to other cancer types. CONCLUSIONS: We have developed a reliable and robust next generation sequencing-based bMSI detection strategy which, in combination with a panel enabling concurrent profiling of bTMB from a single blood draw, may better inform ICB treatment.

Aerobic Exercise Improves Food Reward Systems in Obese Rats via Insulin Signaling Regulation of Dopamine Levels in the Nucleus Accumbens.

The dopaminergic pathway, comprising projections from the ventral tegmental area to the nucleus accumbens, constitutes the core of the brain reward system. Insufficient food reward caused by dopamine signaling dysfunction in the nucleus accumbens is an important contributor to obesity and may be associated with insulin signaling. Aerobic exercise has a positive effect on both preventing and treating obesity. In addition, physical exercise is important in striatal dopamine homeostasis and improves insulin sensitivity in the peripheral and central nervous system. Therefore, we hypothesized that aerobic exercise may increase dopamine levels in the nucleus accumbens through insulin signaling, thus improving food reward in obesity. In the present study, we used a rat model of obesity, induced by high fat diet. Obese rats exhibited lower basic dopamine concentration in the nucleus accumbens induced by eating or extracellular insulin, attenuated insulin signaling, and increased fat preference. Interestingly, an 8-week aerobic exercise regimen reversed these symptoms. In addition, we noted a significant increase in insulin Akt/GSK3-ß signal transduction in the nucleus accumbens. These data demonstrate that aerobic exercise promotes dopamine levels in the nucleus accumbens through insulin signal transduction, which may constitute an important neurobiological mechanism of exercise against obesity.

Ischemic Postconditioning Recovers Cortex Ascorbic Acid during Ischemia/Reperfusion Monitored with an Online Electrochemical System.

As a promising therapeutic treatment, ischemic postconditioning has recently received considerable attention. Although the neuroprotection effect of postconditioning has been observed, a reliable approach that can evaluate the neuroprotective efficiency of postconditioning treatment during the acute period after ischemia remains to be developed. This study investigates the dynamics of cortex ascorbic acid during the acute period of cerebral ischemia before and after ischemic postconditioning with an online electrochemical system (OECS). The cerebral ischemia/reperfusion injury and the neuronal functional outcome are evaluated with triphenyltetrazolium chloride staining, immunohistochemistry, and electrophysiological recording techniques. Electrochemical recording results show that cortex ascorbic acid sharply increases 10 min after middle cerebral artery occlusion and then reaches a plateau. After direct reperfusion following ischemia (i.e., without ischemic postconditioning), the cortex ascorbic acid further increases and then starts to decrease slowly at a time point of about 40 min after reperfusion. In striking contrast, the cortex ascorbic acid drops and recovers to its basal level after ischemic postconditioning followed by reperfusion. With the recovery of cortex ascorbic acid, ischemic postconditioning concomitantly promotes the recovery of neural function and reduces the oxidative damage. These results demonstrate that our OECS for monitoring cortex ascorbic acid can be used as a platform for evaluating the neuroprotective efficiency of ischemic postconditioning in the acute phase of cerebral ischemia, which is of great importance for screening proper postconditioning parameters for preventing ischemic damages.

Assessment of Blood Tumor Mutational Burden as a Potential Biomarker for Immunotherapy in Patients With Non-Small Cell Lung Cancer With Use of a Next-Generation Sequencing Cancer Gene Panel.

IMPORTANCE: Tumor mutational burden (TMB), as measured by whole-exome sequencing (WES) or a cancer gene panel (CGP), is associated with immunotherapy responses. However, whether TMB estimated by circulating tumor DNA in blood (bTMB) is associated with clinical outcomes of immunotherapy remains to be explored. OBJECTIVES: To explore the optimal gene panel size and algorithm to design a CGP for TMB estimation, evaluate the panel reliability, and further validate the feasibility of bTMB as a clinical actionable biomarker for immunotherapy. DESIGN, SETTING, AND PARTICIPANTS: In this cohort study, a CGP named NCC-GP150 was designed and virtually validated using The Cancer Genome Atlas database. The correlation between bTMB estimated by NCC-GP150 and tissue TMB (tTMB) measured by WES was evaluated in matched blood and tissue samples from 48 patients with advanced NSCLC. An independent cohort of 50 patients with advanced NSCLC was used to identify the utility of bTMB estimated by NCC-GP150 in distinguishing patients who would benefit from anti-programmed cell death 1 (anti-PD-1) and anti-programmed cell death ligand 1 (anti-PD-L1) therapy. The study was performed from July 19, 2016, to April 20, 2018. MAIN OUTCOMES AND MEASURES: Assessment of the Spearman correlation coefficient between bTMB estimated by NCC-GP150 and tTMB calculated by WES. Evaluation of the association of bTMB level with progression-free survival and response to anti-PD-1 and anti-PD-L1 therapy. RESULTS: This study used 2 independent cohorts of patients with NSCLC (cohort 1: 48 patients; mean [SD] age, 60 [13] years; 15 [31.2%] female; cohort 2: 50 patients; mean [SD] age, 58 [8] years; 15 [30.0%] female). A CGP, including 150 genes, demonstrated stable correlations with WES for TMB estimation (median r2 = 0.91; interquartile range, 0.89-0.92), especially when synonymous mutations were included (median r2 = 0.92; interquartile range, 0.91-0.93), whereas TMB estimated by the NCC-GP150 panel found higher correlations with TMB estimated by WES than most of the randomly sampled 150-gene panels. Blood TMB estimated by NCC-GP150 correlated well with the matched tTMB calculated by WES (Spearman correlation = 0.62). In the anti-PD-1 and anti-PD-L1 treatment cohort, a bTMB of 6 or higher was associated with superior progression-free survival (hazard ratio, 0.39; 95% CI, 0.18-0.84; log-rank P = .01) and objective response rates (bTMB ≥6: 39.3%; 95% CI, 23.9%-56.5%; bTMB <6: 9.1%; 95% CI, 1.6%-25.9%; P = .02). CONCLUSIONS AND RELEVANCE: The findings suggest that established NCC-GP150 with an optimized gene panel size and algorithm is feasible for bTMB estimation, which may serve as a potential biomarker of clinical benefit in patients with NSCLC treated with anti-PD-1 and anti-PD-L1 agents.