[The effect of large-conductance calcium-activated potassium channels on the migration of pericytes in the mice of senile cochlear stria vascularis]

Objective: To investigate whether large conductance calcium-activated potassium channel (BK(Ca)) was involved in the migration of pericytes (PC) in the mice of senile cochlear stria vascularis capillaries PC. Methods: C57BL/6J mice were divided into 3-month (n=10) and 12-month groups (n=10). Auditory brainstem response (ABR) was used to test the hearing threshold of each group. The immunofluorescence was used to detect the expression changes of osteopontin (OPN) and β-BK(Ca) channels on cochlear stria vascularis PC. The morphological changes of perivascular cells in cochlea were observed by transmission electron microscope (TEM). Cell experiment: The PC, which were in the stria vascularis of the cochlea were primary cultured and identified. A cell senile model was made with D-gal. The appropriate intervention concentration of low galactose (D-gal) was determined by CCK8. β-galactosidase (SA-β-gal) staining was used to evaluate the cell decrept level. The change of BK(Ca) channels current on PC were recorded by whole cell patch clamp technique. The expression of BK(Ca) channels on PC was detected by immunofluorescence. The migration and invasion ability of two groups were detected by using Scratch test and Transwell. The levels of OPN and β-BK(Ca) channels were detected by Western blot. SPSS 22.0 software was used to analyze the data. Results: The ABR threshold in the 12-month group was higher than 3-month group (t=12.66, P<0.01). In the 12-month group, the expression of β-BK(Ca) channel was lower and the expression of OPN was increased (t=14.64, P<0.01; t=20.73, P<0.01). In TEM, cochlear stria vascularis PC were tightly connected to endothelial cells in 3-month group, while PC were loosely connected to endothelial cells or PC soma were separated from the capillary in 12-month group. Cell experiment: The positive rate of PC in the primary cultured cochlear stria vascularis is above 95%. Compared with the SA-β-gal stained cells in the control group, the positive rate of 15 mg/ml D-gal intervention PC was 85% (t=36.90, P<0.01). Whole cell patch clamp BK(Ca) channels current decreased in the D-gal group compared with the young group PC (t=12.18, P<0.05). The OPN expression in the senile group was higher than control group (t=16.30, P<0.01), while the β-BK(Ca) channels expression was decreased (t=11.98, P<0.01; t=15.72, P<0.05), and migration ability raised (t=7.91, P<0.01;t=7.59, P<0.01). After intervened of BK(Ca) channels specific blocker IBTX in the D-gal group, the expression of OPN and migration were increased (t=4.26, P<0.05; t=5.88, P<0.01; t=21.97, P<0.01). Conclusion: PC migration capacity were increased during the senile period, and the expression of β-BK(Ca) channel was decreased. The administration of IBTX, a specific blocker of BK(Ca) channel, at the cell level could increase the migration capacity, suggesting that BK(Ca) might be involved in the migration of PC in the stria vascularis of the aging cochlea.

[Effect of microvascular pericytes of cochlear stria vascularis on endothelial cell permeability in C57BL/6J mice]

Objective: To study the changes in the permeability of the blood labyrinth barrier of the aging cochlea in mice, and to establish a non-contact co-culture model of endothelial cells (EC) and pericytes (PC) to furtherly investigate the cochlear stria vascularis microvascular pericytes impact on the permeability of endothelial cells. Methods: C57BL/6J mice were divided into two groups, three months old as young group, 12 months old as senile group. Cell experiment was divided into four groups, EC group, EC+PC co-culture group, D-gal+EC group and D-gal+EC+PC co-culture group. Auditory brainstem response (auditory brain response, ABR) was used to detect the auditory function of the two groups of mice. Evans blue staining was applied to detect the permeability of the cochlear blood labyrinth barrier of the two groups of mice. Transmission electron microscopy was used to observe the ultrastructure of blood labyrinth barrier endothelial cells, pericytes and tight junctions in the two groups of mice. Immunohistochemistry was used to detect the expression levels of tight junction proteins in the stria vascularis of the cochlea of the two groups of mice. Transwell chamber was used to detect the permeability of endothelial cells. Western blot and immunofluorescence technology were used to detect the expression level of tight junction protein on endothelial cells. SPSS 20.0 software was used to analyze the data. Results: Compared with the young group, the ABR threshold of the aging group was significantly increased, the latency of wave I was prolonged (t=10.25, P<0.01;t=5.61, P<0.05), the permeability of the cochlear blood labyrinth barrier was increased and the expression of tight junction protein on the vascular stria was decreased (P<0.05). The cochlear ultrastructure showed that the cochlear vascular stria microvascular lumen was deformed, the basement membrane thickened and the tight junction gap between endothelium enlarged. The positive rate of ECs and PCs in primary culture was more than 95%. The cells induced by 15 g/L D-gal were determined to be senescent cells. Compared with EC group, the expression of tight junction protein in endothelial cells of D-gal+EC group decreased（t=7.42，P<0.01；t=13.19，P<0.05）and the permeability increased (t=11.17, P<0.01). In the co-culture group, the expression of tight junction protein between endothelial cells in EC+PC co-culture group and D-gal+EC+PC co-culture group increased and the permeability decreased. Conclusions: In aging mice, the permeability of cochlear blood labyrinth barrier will increase and the level of tight junction protein will decrease; in aging state, cochlear vascular stria microvascular pericytes may affect endothelial cell permeability by regulating the expression of tight junction protein.

Potential Pitfalls in the Analysis and Structural Interpretation of Seismic Data from the Mars InSight Mission

The Seismic Experiment for Interior Structure (SEIS) of the InSight mission to Mars, has been providing direct information on Martian interior structure and dynamics of that planet since it landed. Compared to seismic recordings on Earth, ground motion measurements acquired by SEIS on Mars are made under dramatically different ambient noise conditions, but include idiosyncratic signals that arise from coupling between different InSight sensors and spacecraft components. This work is to synthesize what is known about these signal types, illustrate how they can manifest in waveforms and noise correlations, and present pitfalls in structural interpretations based on standard seismic analysis methods. We show that glitches, a type of prominent transient signal, can produce artifacts in ambient noise correlations. Sustained signals that vary in frequency, such as lander modes which are affected by variations in temperature and wind conditions over the course of the Martian Sol, can also contaminate ambient noise results. Therefore, both types of signals have the potential to bias interpretation in terms of subsurface layering. We illustrate that signal processing in the presence of identified nonseismic signals must be informed by an understanding of the underlying physical processes in order for high fidelity waveforms of ground motion to be extracted. While the origins of most idiosyncratic signals are well understood, the 2.4 Hz resonance remains debated and the literature does not contain an explanation of its fine spectral structure. Even though the selection of idiosyncratic signal types discussed in this paper may not be exhaustive, we provide guidance on best practices for enhancing the robustness of structural interpretations.

Numerical Study of Ultra-Broadband Metamaterial Perfect Absorber Based on Four-Corner Star Array

In recent years, research on solar absorbers provides a significant breakthrough to solve the energy crisis. A perfect solar absorber based on a four-corner star array is designed and the absorption performance is analyzed numerically. The results show that the absorber reaches more than 90% of the full band in the range of 400-2000 nm. In particular, the absorption efficiency of the continuous more than 95% of the bandwidth reached 1391 nm, and the average absorption efficiency of the whole study band is more than 98%, and the loss of the solar spectrum only accounted for 2.7%. At the same time, the absorption efficiency can be adjusted by changing the geometric structure of the absorber. In addition, due to the perfect symmetry of the structure, it has an excellent insensitivity of the incident angle and polarization angle. In general, the proposed solar absorber has exciting prospects in solar energy collection and utilization, photothermal conversion and other related fields.

Dual-color meta-image display with a silver nanopolarizer based metasurface

Plasmonic metallic nanostructures with anisotropic design have unusual polarization-selective characteristic which can be utilized to build nanopolarizers at the nanoscale. Herein, we propose a dual-color image display platform by reconfiguring two types of silver nanoblocks in a single-celled metasurface. Governed by Malus's law, the two types of silver nanoblocks both acting as nanopolarizers with different orientations can continuously modulate the intensity of incident linearly polarized red and green light pixel-by-pixel, respectively. As a result, an ultra-compact, high-resolution, and continuous-greyscale dual-color image can be recorded right at the surface of the meta-device. We demonstrate the dual-color Malus metasurface by successfully encoding and decoding a red-green continuously-grayscale image into a metasurface sample. The experimentally captured meta-image with high-fidelity and resolution as high as 63500 dots per inch (dpi) has verified our proposal. With the advantages such as continuous grayscale modulation, ultrathin, high stability and high density, the proposed dual-color encoded metasurfaces can be readily used in ultra-compact image displays, high-end anti-counterfeiting, high-density optical information storage and information encryption, etc.

Tunable circular dichroism based on graphene-metal split ring resonators

The chiroptical response of the chiral metasurface can be characterized by circular dichroism, which is defined as the absorption difference between left-handed circularly polarized incidence and right-handed circularly incidence. It can be applied in biology, chemistry, optoelectronics, etc. Here, we propose a dynamically tunable chiral metasurface structure, which is composed of two metal split-ring resonators and a graphene layer embedded in dielectric. The structure reflects right-handed circularly polarized waves and absorbs left-handed circularly polarized waves under normal incidence. The overall unit structural parameters of the chiral metasurface were discussed and analyzed, and the circular dichroism was 0.85 at 1.181 THz. Additionally, the digital imaging function can be realized based on the chiral metasurface structure, and the resolution of terahertz digital imaging can be dynamically tuned by changing the Fermi level of graphene. The proposed structure has potential applications in realizing tunable dynamic imaging and other communication fields.

The oxidative stress caused by atrazine in root exudation of Pennisetum americanum (L.) K. Schum

Pearl millet (Pennisetum americanum (L.) K. Schum) has been proven as a potential remediation plant of the pollution caused by atrazine. Plants used in remediation can release root exudates to communicate with rhizosphere microorganisms and accelerate the removal of pollutants in soil. However, the response of pearl millet root exudates under atrazine stress has remained unclear. In this study, hydroponic experiments were conducted at Northeast Agricultural University, Harbin, China, to investigate the oxidative stress response and the changes in composition of root exudates in pearl millet plants that were exposed to 19.4 mgL^-1 of atrazine, compared to the untreated control. The experiment was established as six treatments with exposure to no atrazine for 2, 4 and 6 days (CK-2, CK-4, CK-6) and 19.4 mgL^-1 atrazine for 2, 4 and 6 days (AT-2, AT-4, AT-6), respectively. The results suggest that the growth of the seedlings changed slightly when exposed to atrazine for 2 days. The content of thiobarbituric acid reactive substances exposed to atrazine for 6 days increased 26% compared with the treatment that was exposed for 2 days. Moreover, the reactive oxygen species in test plant obviously increased when exposed to atrazine for 6 days. In addition, the activity of superoxide dismutase increased from 30.82 ug^-1 to 37.33 ug^-1 fresh weight after 6 days of exposure to atrazine. The results of a nontargeted metabolomic analysis suggest that carbohydrate metabolism, fatty acid metabolism and amino acid metabolism in pearl millet were obviously affected by the oxidative stress caused by atrazine. The contents of sphinganine and methylimidazole acetaldehyde in CK-6 increased by 5.14 times and 2.05 times, respectively, compared with those of CK-2. Furthermore, the contents of (S)-methylmalonic acid semialdehyde and 1-pyrroline-2-carboxylic acid decreased by 0.56 times and 0.5 times, respectively, compared with the AT-6. These results strongly suggest that the changes observed in the composition of root exudates in pearl millet seedlings can be attributed to the oxidative stress caused by atrazine.

An Enhanced Plastic Optical Fiber-Based Surface Plasmon Resonance Sensor with a Double-Sided Polished Structure

An enhanced plastic optical fiber (POF)-based surface plasmon resonance (SPR) sensor is proposed by employing a double-sided polished structure. The sensor is fabricated by polishing two sides of the POF symmetrically along with the fiber axis, and a layer of Au film is deposited on each side of the polished region. The SPR can be excited on both polished surfaces with Au film coating, and the number of light reflections will be increased by using this structure. The simulation and experimental results show that the proposed sensor has an enhanced SPR effect. The visibility and full width at half maximum (FWHM) of spectrum can be improved for the high measured refractive index (RI). A sensitivity of 4284.8 nm/RIU is obtained for the double-sided POF-based SPR sensor when the measured liquid RI is 1.42. The proposed SPR sensor is easy fabrication and low cost, which can provide a larger measurement range and action area to the measured samples, and it has potential application prospects in the oil industry and biochemical sensing fields.

Immersive visualisation of intracardiac blood flow in virtual reality on a patient with HLHS

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): NIHR i4i funded 3D Heart project Wellcome/EPSRC Centre for Medical Engineering [WT 203148/Z/16/Z]

onbehalf

3D Heart Project

Background/Introduction: Virtual Reality (VR) for surgical and interventional planning in the treatment of Congenital Heart Disease (CHD) is an emerging field that has the potential to improve planning. Particularly in very complex cases, VR permits enhanced visualisation and more intuitive interaction of volumetric images, compared to traditional flat-screen visualisation tools. Blood flow is severely affected by CHD and, thus, visualisation of blood flow allows direct observation of the cardiac maladaptions for surgical planning. However, blood flow is fundamentally 3D information, and viewing and interacting with it using conventional 2D displays is suboptimal. 

Purpose

To demonstrate feasibility of blood flow visualisation in VR using pressure and velocity obtained from a computational fluid dynamic (CFD) simulation of the right ventricle in a patient with hypoplastic left heart syndrome (HLHS) as a proof of concept.

Methods

 We extend an existing VR volume rendering application to include CFD rendering functionality using the Visualization Toolkit (VTK), an established visualisation library widely used in clinical software for visualising medical imaging data. Our prototype displays the mesh outline of the segmented heart, a slicing plane showing blood pressure on the plane within the heart, and streamlines of blood flow from a spherical source region. Existing user tools were extended to enable interactive positioning, rotation and scaling of the pressure plane and streamline origin, ensuring continuity between volume rendering and CFD interaction and, thus, ease of use. We evaluated if rendering and interaction times were low enough to ensure a comfortable, interactive VR experience. Our performance benchmark is a previous study showing VR is acceptable to clinical users when rendering speed is at least 90 fps.

Results

CFD simulations were successfully rendered, viewed and manipulated in VR, as shown in the Figure. Evaluating performance, we found that visualisation of the mesh and streamlines was at an acceptably high and stable frame rate, over 150fps. User interactions of moving, rotating or scaling the mesh or streamlines origin did not significantly reduce this frame rate. However, rendering the  pressure slicing plane reduced frame rate by an unacceptable degree, to less than 10fps.  

Conclusion

Visualisation of and interaction with CFD simulation data was successfully integrated into an existing VR application. This aids in surgery and intervention planning for defects heavily relying on blood flow simulation, and lays a foundation for a platform for clinicians to test interventions in VR. Pressure plane rendering performance will require significant optimisation, potentially addressed by updating the pressure plane data separately from the main, VR rendering.

Abstract Figure. An example render of CFD simulation

Automatic orientation cues for intuitive immersive interrogation of 3D echocardiographic images in virtual reality using deep learning

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): NIHR i4i funded 3D Heart Project Wellcome / EPSRC Centre for Medical Engineering (WT 203148/Z/16/Z)

onbehalf

3D Heart Project

Background/Introduction:

In echocardiography (echo), image orientation is determined by the position and direction of the transducer during examination, unlike cardiovascular imaging modalities such as CT or MRI. As a result, when echo images are first shown their display orientation has no external anatomical landmarks, thus the user has to identify anatomical landmarks in the regions of interest to understand the orientation. 

Purpose

To display an anatomical model of a standard heart, automatically aligned to an acquired patient’s 3D echo image - assisting image interpretation by quickly orienting the viewer. 

Methods

 

47 echo datasets from 13 pediatric patients with hypoplastic left heart syndrome (HLHS) were annotated by manually indicating the cardiac axes in both ES and ED volumes. We chose a view akin to the standard four chamber view in healthy hearts as the reference view, showing the AV valves, the right atrium, the left atrium and the hypoplastic ventricle. We then trained a deep convolutional neural network (CNN) to predict the rotation required for re-orientation to the reference view. Three data strategies were explored: 1) using 3D images to estimate orientation, 2) using three orthogonal slices only (2.5D approach) and 3) using the central slice only (2D approach). Three different algorithms were investigated: 1) an orientation classifier, 2) an orientation regressor with mean absolute angle error, and 3) an orientation regressor with geodesic loss. The data was split into training, validation and test sets with a 8:1:1 ratio. The training data was augmented by applying random rotations in the range [−10◦, +10◦] and updating labels accordingly. The model with smallest validation error was applied in tandem with the VR visualisation of the echo volumes. 

Results

Experimental results suggest that a 2.5D CNN classifying discrete integer angles performs best in re-orienting volumetric images to the reference view, with a mean absolute angle error on the test set of 9.0 deg (test set error ranges from 10.8 to 25.9 deg. for other algorithms). An HLHS volumetric data (left) is automatically aligned with the cardiac model (right) using our trained network when loaded in VR as shown in Figure 1. The volume and the model are both cropped at the referencing plane.

Conclusion

A deep learning network to align 3D echo images to a reference view was successfully trained and then integrated  into VR to reorient echo volumes to match a standard anatomical view. This work demonstrates the potential of combining artificial intelligence and VR in medical imaging, although further user study is expected to evaluate its clinical impact.

Caption for Abstract Picture

 The VR user interface informs the user of the 3D echo image orientation, automatically aligning it with an anatomical model, here showing the four chamber apical view.

Abstract Figure. Deep learning model integrated into VR

Nicosulfuron inhibits atrazine biodegradation by Arthrobacter sp. DNS10:Influencing mechanisms insight from bacteria viability, gene transcription and reactive oxygen species production

Nicosulfuron is a sulfonylurea family herbicide which is commonly applied together with the triazine herbicide atrazine in agricultural practice. However, whether nicosulfuron can influence the biodegradation of atrazine is unclear. Therefore, the influence of nicosulfuron on atrazine removal as well as on cell viability and transcription of atrazine chlorohydrolase gene (trzN) in Arthrobacter sp. DNS10 was investigated in this study. Our results demonstrated that 76.0% of atrazine was degraded in the absence of nicosulfuron after 48h of culture, whereas 63.9, 49.1 and 42.6% was degraded in the presence of 1, 5, and 10 mg/L of nicosulfuron, respectively. Nicosulfuron also induced an increase in the level of intracellular reactive oxygen species (ROS), thereby damaging the cell membrane integrity and inhibiting the growth of the strain DNS10. Flow cytometry analysis revealed that the cell viability of strain DNS10 decreased with an increase in nicosulfuron concentration. The transcription of trzN in strain DNS10 exposed to the three described levels of nicosulfuron was 0.99, 0.72 and 0.52 times, respectively, that without nicosulfuron. In brief, nicosulfuron could inhibit atrazine removal efficiency by strain DNS10 by inducing the over-production of ROS which ultimately enhances the population of membrane-damaged cells, as well as reducing cell viability and trzN transcription. The outcomes of the present study provide new insights into the mechanism of nicosulfuron inhibition on atrazine biodegradation by strain DNS10.

A switchable dimeric yttrium complex and its three catalytic states in ring opening polymerization

A dimeric yttrium phenoxide complex can be oxidized in a stepwise fashion to access three oxidation states. The three states show different activity in the ring opening polymerization of cyclic esters and epoxides.

Diagnostic value of combined nucleic acid and antibody detection in suspected COVID-19 cases

OBJECTIVES

Nucleic acid testing is the gold standard method for the diagnosis of coronavirus disease 2019 (COVID-19); however, large numbers of false-negative results have been reported. In this study, nucleic acid detection and antibody detection (IgG and IgM) were combined to improve the testing accuracy of patients with suspected COVID-19.

STUDY DESIGN

The positive rate of nucleic acid detection and antibody detection (IgG and IgM) were compared in suspected COVID-19 patients.

METHODS

A total of 71 patients with suspected COVID-19 were selected to participate in this study, which included a retrospective analysis of clinical features, imaging examination, laboratory biochemical examination and nucleic acid detection and specific antibody (IgM and IgG) detection.

RESULTS

The majority of participants with suspected COVID-19 presented with fever (67.61%) and cough (54.93%), and the imaging results showed multiple small patches and ground-glass opacity in both lungs, with less common infiltration and consolidation opacity (23.94%). Routine blood tests were mostly normal (69.01%), although only a few patients had lymphopenia (4.23%) or leucopenia (12.68%). There was no statistical difference in the double-positive rate between nucleic acid detection (46.48%) and specific antibody (IgG and IgM) detection (42.25%) (P = 0.612), both of which were also poorly consistent with each other (kappa = 0.231). The positive rate of combined nucleic acid detection and antibody detection (63.38%) was significantly increased, compared with that of nucleic acid detection (46.48%) and that of specific antibody (IgG and IgM) detection (42.25%), and the differences were statistically significant (P = 0.043 and P = 0.012, respectively).

CONCLUSIONS

Nucleic acid detection and specific antibody (IgG and IgM) detection had similar positive rates, and their combination could improve the positive rate of COVID-19 detection, which is of great significance for diagnosis and epidemic control.

Abstract 338: Limited Reduction of Heart Rate Promotes Cardiac Regeneration by Switching the Energy Metabolic Mode in Cardiomyocytes

Aims: Lack of cardiac regeneration with robust fibrosis response to the acute myocardial injury is the main obstacle to clinical treatment of cardiovascular diseases in humans. Stimulating the proliferation of endogenous cardiomyocytes (CMs) and replacing the scarred tissue with new functional CMs is a potential therapeutic strategy to the patients with heart failure. Heart rate reduction (HRR) is regarded as an effective clinical treatment for myocardial infarction. However, the mechanism of HRR promoting the recovery of cardiac function after injury still remains controversial, and whether there is any endogenous CM proliferation induced by HRR is undefined.

Methods and results: The beating of CMs was reduced in vitro and heart rate (HR) of adult mice and different animal models of myocardial injury were modulated by six antiarrhythmic drugs to determine the role of HR in CM proliferation and cardiac repair. RNA-seq, extracellular flux analysis, metabolic flux analysis, and metabonomics were used to study the CM metabolism after HR modulation. We verified that reducing the beating can induce CM proliferation both in vitro and in vivo physiologically, and HRR also promoted cardiac regenerative repair after myocardial injury as well, reversely, increasing HR showed the opposite effect. Mechanistically, HRR reduced energy metabolism requirements and total ATP production of CMs but switched energy metabolic mode that the proportion of ATP production from aerobic glycolysis was increased, while from fatty acid oxidation was decreased. The switching of energy metabolic mode in CMs occurred in synchrony with the changes of glycolytic enzymes activities, these enzymes, including PFKFB3, PKM2, GAPDH, induced G1/S transition for cell cycle re-entry of CMs by upregulating the expression of cyclin D and CDK4/6 and facilitate substrates into the biomass needed to produce a new cell by biosynthesis. This coordinating function of glycolytic enzymes contributed to CM proliferation.

Conclusion: Together, these results demonstrate that reduction of heart rate promotes CM proliferation by switching the energy metabolic mode, and highlight the potential therapeutic role of HRR in regenerative medicine.

Activation of the STAT1 Pathway Accelerates Periodontitis in Nos3-/- Mice

Early studies on the etiology and pathogenesis of hypertension have shown that it has a considerable association with inflammation and the immune response as well as periodontitis. Clinical studies have also shown that hypertension can promote the periodontal tissue destruction caused by periodontitis. However, the underlying mechanisms remain unclear. This study aimed to explore the possible mechanisms of how hypertension aggravates periodontitis. Treatment with or without the signal transducer and activator of transcription 1 (STAT1) inhibitor fludarabine was performed in an endothelial nitric oxide synthase gene knockout-related (Nos3^-/-) mouse model with the hypertension phenotype of periodontitis induced by bacteria. Micro-computed tomography, immunohistochemistry, Western blot, quantitative reverse transcription polymerase chain reaction, immunofluorescence, and ELISA were performed. We demonstrated that Nos3^-/--related hypertension increases bone resorption and periodontal destruction in periodontitis lesion areas, which can be inhibited by the STAT1 inhibitor. Experimental data also showed that Nos3^-/- significantly increased macrophage infiltration and proinflammatory cytokine expression in the periodontitis lesion area, which is dependent on the angiotensin II-induced STAT1 pathway. Inhibition of STAT1 in vivo can decrease the expression of proinflammatory cytokines and macrophage infiltration. Furthermore, data in this study showed that Nos3^-/--related hypertension further downregulated the STAT3 anti-inflammatory function and its downstream chemokine expression in a STAT1-dependent manner. By applying RAW 264.7 and L929 cell lines and monocytes isolated from Nos3^-/- mice, we confirmed that activation of the STAT1 pathway inhibits STAT3 and its downstream pathway and promotes inflammatory cytokine expression in vitro. Collectively, our current study demonstrated that STAT1 plays an indispensable role in the Nos3^-/--related hypertension with aggravation of periodontitis, suggesting that STAT1 may be a key target for the treatment of periodontitis with hypertension.

Accuracy of molecular diagnostic tests for drug-resistant tuberculosis detection in China: a systematic review

OBJECTIVE: To evaluate the accuracy of molecular diagnostics for the detection of drug-resistant tuberculosis (TB) in Chinese patients.METHOD: Seven databases were searched for eligible studies that evaluated the accuracy of molecular diagnostics against drug susceptibility testing (DST) for detecting drug resistance. A bivariate random-effects meta-analysis was conducted to pool sensitivity and specificity by the index test and drug resistance type.RESULTS: A total of 159 studies were included. Compared with DST (reference standard), Xpert^® could diagnose rifampicin (RMP) resistant TB accurately, with a pooled sensitivity and pooled specificity of 92% (95%CI 90-94) and 98% (95%CI 97-98), respectively. Line-probe assays (LPAs) also performed well for RMP resistance, with a pooled sensitivity of 91% (95%CI 88-93) and pooled specificity of 98% (95%CI 96-99), but not for isoniazid (INH) or second-line drugs due to lower sensitivity (<80%). The pooled sensitivity of GeneChip^® microarrays for RMP, INH and multidrug resistance was 89% (95%CI 86-91), 79% (95%CI 75-82) and 79% (95%CI 73-84), respectively, and the specificities were all >97%. Similarly, the MeltPro^® TB/STR assay had better sensitivity and specificity for first-line drugs, varying from 87% to 89% and 97% to 98%, respectively, than for second-line drugs.CONCLUSION: The Xpert assay, LPA, GeneChip assay, and MeltPro assay are credible methods with high accuracy for RMP resistance detection, but they may not be appropriate for other anti-tuberculosis drugs due to low sensitivity.

Modulation of inflammatory response and gut microbiota in ankylosing spondylitis mouse model by bioactive peptide IQW

AIMS

Ankylosing spondylitis (AS) is a widespread and chronic inflammatory autoimmune disease of unknown provenance. Naturally occurring peptides and proteins have shown significant promise as modulators of immune responses. Thus, the aims of this study were to assess the protective effects of the bioactive peptide IQW (Ile-Gln-Trp) with respect to inflammatory indicators, gut microbiota and oxidative stress, and to examine the potential mechanisms of these effects.

METHODS AND RESULTS

A mouse model was prepared by four injections of human proteoglycan extract (2 mg) in dimethyldioctadecylammonium solution (2 mg) over an interval of 2 weeks. Enzyme-linked immunosorbent assay results for the markers of oxidative stress and inflammation in the AS mice revealed increased concentrations of malondialdehyde, IL-6, IL-1β and TNF-α, along with decreased concentrations of catalase (CAT), glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD). Treatment with IQW was found to decrease the concentrations of IL-6, IL-1β and TNF-α, and increase the concentrations of CAT, GSH-PX and SOD. Moreover the quantification of the microbiota via 16s rRNA sequencing revealed a reduced microbial diversity in the AS mice, while a significantly increased microbial diversity was displayed by those treated with IQW. Whereas, there was a significant reduction in the relative abundance of Bacteroidetes and an increased relative abundance of Verrucomicrobia in AS mice, this was reversed following the IQW treatment.

CONCLUSIONS

The results demonstrated that IQW exerts a beneficial influence in AS by delaying progression of the disease, reducing the arthritic grade of intervertebral joints, altering the concentrations of cytokines and modulating the microbial diversity and composition.

SIGNIFICANCE AND IMPACT OF THE STUDY

Oral IQW treatment might represent a new approach to mitigate the onset and development of AS.

Distinct cardiac energy metabolism and oxidative stress adaptations between obese and non-obese type 2 diabetes mellitus

Background: Little is known about the pathophysiological diversity of myocardial injury in type 2 diabetes mellitus (T2DM), but analyzing these differences is important for the accurate diagnosis and precise treatment of diabetic cardiomyopathy. This study aimed to elucidate the key cardiac pathophysiological differences in myocardial injury between obese and non-obese T2DM from mice to humans.

Methods: Obese and non-obese T2DM mouse models were successfully constructed and observed until systolic dysfunction occurred. Changes in cardiac structure, function, energy metabolism and oxidative stress were assessed by biochemical and pathological tests, echocardiography, free fatty acids (FFAs) uptake fluorescence imaging, transmission electron microscopy, etc. Key molecule changes were screened and verified by RNA sequencing, quantitative real-time polymerase chain reaction and western blotting. Further, 28 human heart samples of healthy population and T2DM patients were collected to observe the cardiac remodeling, energy metabolism and oxidative stress adaptations as measured by pathological and immunohistochemistry tests.

Results: Obese T2DM mice exhibited more severe cardiac structure remodeling and earlier systolic dysfunction than non-obese mice. Moreover, obese T2DM mice exhibited severe and persistent myocardial lipotoxicity, mainly manifested by increased FFAs uptake, accumulation of lipid droplets and glycogen, accompanied by continuous activation of the peroxisome proliferator activated receptor alpha (PPARα) pathway and phosphorylated glycogen synthase kinase 3 beta (p-GSK-3β), and sustained inhibition of glucose transport protein 4 (GLUT4) and adipose triglyceride lipase (ATGL), whereas non-obese mice showed no myocardial lipotoxicity characteristics at systolic dysfunction stage, accompanied by the restored PPARα pathway and GLUT4, sustained inhibition of p-GSK-3β and activation of ATGL. Additionally, both obese and non-obese T2DM mice showed significant accumulation of reactive oxygen species (ROS) when systolic dysfunction occurred, but the NF-E2-related factor 2 (Nrf2) pathway was significantly activated in obese mice, while was significantly inhibited in non-obese mice. Furthermore, the key differences found in animals were reliably verified in human samples.

Conclusion: Myocardial injury in obese and non-obese T2DM may represent two different types of complications. Obese T2DM individuals, compared to non-obese individuals, are more prone to develop cardiac systolic dysfunction due to severe and persistent myocardial lipotoxicity. Additionally, anti-oxidative dysfunction may be a key factor leading to myocardial injury in non-obese T2DM.