[Cathepsin L mediates glomerular endothelial cell injury by cleavaging complement C3 in trichloroethylene-sensitized mice]

Objective: To observe the expressions of complement 3 (C3) and endothelial cell injury-associated proteins before and after cathepsin L (CTSL) blockade in renal injury of trichloroethylene (TCE) -sensitized mice. Methods: In June 2018, 41 SPF female BALB/c mice were divided respectively into blank control group (n=5) , vehicle control group (n=5) , TCE group (n=15) and TCE+CTSLi group (n=16) to establish trichloroethylene-sensitized mice model by pretreating the mice with intraperitoneal injection of CTSL inhibitor (CTSLi) and using TCE for the first and last challenge. According to the skin sensitization score, the mice were divided into positive group and negative group. 72 hours after the last challenge, the renal function indexes of the mice were detected, the pathological changes of mice kidneys were observed, and the glomerular C3 and endothelial cell damage-related proteins [vascular cell adhesion molecule 1 (VCAM-1) , tight junction protein 5 (Claudin-5) and Syndecan-1] expression levels were detected. Results: The sensitization rates of mice in TCE group and TCE+CTSLi group were 53.3% (8/15) and 50.0% (8/16) , respectively, and there was no significant difference between the two groups (P>0.05) . Compared with vehicle control group and the corresponding TCE negative group, the serum creatinine (CRE) and blood urea nitrogen (BUN) levels of mice in the TCE positive group was increased, while the TCE positive group were higher than the TCE+CTSLi positive group (P<0.05) . Pathological examination showed obvious vacuolar degeneration and cellular edema in the mice kidney of the TCE positive group. In the TCE+CTSLi positive group, the above pathological damage was significantly improved. Immunohistochemical results showed that the expression of glomerular C3 fragment and VCAM-1 in TCE positive group were significantly higher than that of the vehicle control and TCE negative group (P<0.05) , while TCE+CTSLi positive group was significantly lower than that of TCE positive group (P<0.05) . Western blot test results showed that the relative expression levels of Claudin-5 and Syndecan-1 protein in the mice glomeruli of TCE positive group were significantly lower than those in the vehicle control group and TCE negative group (P<0.05) . Compared with the TCE positive group, the Claudin-5 protein was increased in the kidney of the TCE+CTSLi positive group, but the difference was not statistically significant (P>0.05) , while the Syndecan-1 protein was significantly increased in the TCE+CTSLi positive group (P<0.05) . Conclusion: CTSL may mediate the glomerular structural damage by cutting complement C3, activating the complement system, damaging endothelial cell structural protein Syndecan-1 and overexpressing adhesion molecule VCAM-1 in TCE-sensitized mice. Inhibiting the expression of CTSL may be an effective way to protect the glomerular integrity of structure and function in pharmacology.

Setting the new FRAX reference threshold without bone mineral density in Chinese postmenopausal women

PURPOSE

Despite the large number of osteoporosis patients in China, the diagnosis and treatment rates remain low. The Fracture Risk Assessment Tool (FRAX) can be used to effectively evaluate fracture risk. In this study, we explored the Chinese-specific thresholds of FRAX without the T-score.

METHODS

In all, 264 postmenopausal women aged > 50 years were randomly recruited from community-medical centers. All subjects completed self-reported questionnaires, BMD measurements, and spinal radiographs. The 10-year hip and major osteoporotic fracture risks were calculated by FRAX. A new threshold for both 10-year hip and major osteoporotic fracture risk was explored with receiver operating characteristic (ROC) curve analysis.

RESULTS

Overall, 92 subjects were diagnosed with osteoporosis. Among them, 14 participants with T-score > - 2.5 were diagnosed with osteoporosis based on clinical fractures. ROC analysis showed the cut-off value of the 10-year hip osteoporotic fracture for detecting osteoporosis was 0.95%, while that of 10-year major osteoporotic fracture was 4.95%. The sensitivity and specificity of the 10-year hip osteoporotic fracture probability for detecting osteoporosis were 0.86 and 0.59, respectively, while the guideline-recommended threshold had a sensitivity of 0.49 and specificity of 0.83. The sensitivity and specificity of the 10-year major osteoporotic fractures with the new threshold were 0.76 and 0.69, respectively, while the recommended threshold had a sensitivity of 0 and specificity of 1.

CONCLUSION

Current guideline-recommended FRAX thresholds without BMD showed low sensitivity. Therefore, 10-year osteoporotic hip fracture probability ≥ 0.95% and 10-year osteoporotic major fracture probability ≥ 4.95% are recommended as the new thresholds.

[Protective effects of taurine on neurons and microglia in Parkinson's disease-like mouse model induced by paraquat]

Objective: To investigate the protective effect of taurine (Tau) on hippocampus, substantia nigra neurons and microglia in paraquat (PQ) -induced Pakinson's disease-like mice. Methods: In April 2019, the specific pathogen free (SPF) C57BL/6 mice (n=36) were randomly divided into control group (NaCl) , Tau control group (150 mg/kg) , PQ exposure group (10 mg/kg PQ group, 15 mg/kg PQ group) , Tau intervention group (Tau+10 mg/kg PQ group, Tau+15 mg/kg PQ group) , respectively. Tau was used in 1 h before PQ administration for consecutive 6 weeks (twice per week) . General and neurobehavioral tests (Traction test, Open field test, Forced Swimming test, Tail suspension test, High plus maze and Object recognition test) were performed to test motor and cognitive function. After neuroethology detection, mice were euthanized and brains were collected. Nissl staining was used to detect the changes of the number and morphology of Nissl bodies in hippocampus and substantia nigra neurons of mice. Immunohistochemistry (IHC) was used to test the levels of neuron marker neuronal nuclei antigen (NeuN) , substantia nigra dopaminergic neuron marker tyrosine hydroxylase (TH) , α-synuclein (α-syn) , microglia markers ionized calcium bindingadaptor molecule-1 (Iba-1) , inducible nitric oxide synthase (iNOS) and interleukin-1β (IL-1β) in mice substantia nigra. The coexpression of Iba-1 and TH double-labeling, α-syn and TH double-labeling in mice substantia nigra were measured by immunofluorescence double staining. Results: General behavioral changes such as slow reaction and reduced action occurred in mice of PQ group. Compared with the control group, the scores of Traction test, and the time ratio of new object recognition in the PQ group decreased (P<0.05) , the fixed time of Swimming test and Tail suspension test increased (P<0.05) , the horizontal crawl number and vertical times of Open field test and the ratio of open arm residence time of High plus maze in the 15 mg/kg PQ group decreased (P<0.05) . Compared with the PQ group, the same dose of Tau+PQ group showed increased scores in Traction test (P<0.05) and decreased fixed time of Swimming test and Tail suspension test (P<0.05) . Compared with the 15 mg/kg PQ group, the horizontal crawl number of Open field test and the time ratio of new object recognition increased in the Tau+15 mg/kg PQ group (P<0.05) . Compared with the control group, the PQ group showed a decrease in the number of Nissl body in the hippocampus and substantia nigra (P<0.05) , a decrease in the number of NeuN and TH positive cells in the substantia nigra (P<0.05) , with a large number of α-syn deposition, Iba-1 activation of microglia cells, and an increase in the expression of inflammatory factors (IL-1β, iNOS) in the hippocampus and substantia nigra (P<0.05) . Compared with the PQ group, the same dose of Tau+PQ group showed the number of Nissl in the hippocampus and substantia nigra was significantly increased (P<0.05) , the number of NeuN and TH positive cells in the substantia nigra was significantly increased (P<0.05) , the expression levels of α-syn, Iba-1 and inflammatory factors (IL-1β, iNOS) in the substantia nigra were significantly decreased (P<0.05) . Conclusion: Tau could protect PQ-induced degeneration of substantia nigra dopaminergic neurons and hippocampal neuron loss by inhibiting the activation of microglia cells and release of inflammatory factors, and effectively improve the neurobehavioral and brain histopathological changes of PQ-induced PD-like mice.

Elastic wave velocity dispersion in polycrystals with elongated grains: Theoretical and numerical analysis

The phase velocity dispersion of longitudinal waves in polycrystals with elongated grains of arbitrary crystallographic symmetry is studied in all frequency ranges by the theoretical second-order approximation (SOA) and numerical three-dimensional finite element (FE) models. The SOA and FE models are found to be in excellent agreement for three studied polycrystals: cubic Al, Inconel, and a triclinic material system. A simple Born approximation for the velocity, not containing the Cauchy integrals, and the explicit analytical quasi-static velocity limit (Rayleigh asymptote) are derived. As confirmed by the FE simulations, the velocity limit provides an accurate velocity estimate in the low-frequency regime where the phase velocity is nearly constant on frequency; however, it exhibits dependence on the propagation angle. As frequency increases, the phase velocity increases towards the stochastic regime and then, with further frequency increase, behaves differently depending on the propagation direction. It remains nearly constant for the wave propagation in the direction of the smaller ellipsoidal grain radius and decreases in the grain elongation direction. In the Rayleigh and stochastic frequency regimes, the directional velocity change shows proportionalities to the two elastic scattering factors even for the polycrystal with the triclinic grain symmetry.

The association between napping and the risk of cardiovascular disease and all-cause mortality: a systematic review and dose-response meta-analysis

Background

Napping is a habit prevalent worldwide and occurs from an early age. Some sleep specialists have suggested it as a potential public health tool due to the prevalence of sleep disorder. However, the association between napping and the risk of cardiovascular disease (CVD) and all-cause mortality remains unclear.

Purpose

To assess the association between napping and the risk of CVD and all-cause mortality.

Methods

We conducted a systematic search of Medline, Embase and Cochrane databases from inception through December 2019 for prospective cohort studies investigating the association between napping and the risk of CVD and/or all-cause mortality. Overall estimates were calculated using random effect models with inverse variance weighting. Dose-response meta-analysis was performed using restricted cubic spline models. The results were reported as hazard ratio (HR) and 95% confidence interval (CI).

Results

A total of 313651 participants (57.8% female, 38.9% took naps) from 20 cohort studies were included in the analysis. Overall, pooled analysis detected no association between daytime nap and CVD (HR 1.13, 95% CI 0.99–1.28). However, in subgroup analysis including only participants who were female (HR 1.31, 95% CI 1.09–1.58), older (age&gt;65 years) (HR 1.36, 95% CI 1.07–1.72), or took a longer nap (nap time&gt;60 minutes) (HR 1.34, 95% CI 1.05–1.63), napping was significantly associated with a higher risk of CVD comparing to not napping. All-cause mortality was associated with napping overall (HR 1.19, 95% CI 1.12–1.26), and effect sizes were even more pronounced in females (HR 1.22, 95% CI 1.13–1.31), older participants (HR 1.27, 95% CI 1.11–1.45) and those who took a long nap (HR 1.30, 95% CI 1.12–1.47). Furthermore, after stratifying participants by night sleep time (&lt;6 and &gt;6h/day), no significant association was detected except those who slept &gt;6h/day at night and took a long nap (HR 1.13, 95% CI 1.03–1.24). Dose-response analysis showed a J-curve relation between nap time and CVD (Figure 1). The HR decreased from 0 to 25 min/day, followed by a sharp increase in the risk at longer times. A positive linear relationship between nap time and all-cause mortality was also observed.

Conclusion

Long napping over 60 minutes per day is associated with increased risks of CVD and all-cause mortality. Night sleep duration may play a role in the relation between napping and all-cause mortality. Further, large-scale prospective cohort studies need to confirm our conclusion and investigate the underlying mechanisms driving these associations.

Funding Acknowledgement

Type of funding source: None

Gen-editing to model Short QT syndrome type 5 using human-induced pluripotent stem cell-derived cardiomyocytes

Aims

Short QT syndrome (SQTS), a disorder associated with characteristic electrocardiogram QT-segment abbreviation, predisposes afflicted patients to sudden cardiac death. Despite some progress in assessing the organ level pathophysiology and genetic changes of the disorder, the understanding of the human cellular phenotype and discovering of an optimal therapy has lagged due to a lack of appropriate human cellular models of the disorder. The aim of this study was to establish a cellular model of SQTS type 5 using human-induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) and gene-edited cell line using CRISPR/CAS9.

Methods and results

This study recruited one patient with short QT syndrome type 5 carrying a mutation in CACNb2 gene as well as one healthy control subject. We generated hiPSCs from their skin fibroblasts, and differentiated hiPSCs into cardiomyocytes (hiPSC-CMs) for physiological. Isogenic control hiPSC-CMs generated by the CRISPR/CAS9 technique were also used for the study.

The hiPSC-CMs from the patient showed a reduced calcium current (ICa-L) density and shortened action potential duration (APD) compared with healthy control hiPSC-CMs and isogenic hiPSC-CMs. Furthermore, they demonstrated abnormal rhythmic activities. Carbachol increased the arrhythmic events in SQTS significantly but not in healthy and isogenic control cells. Gene and protein expression profiling showed a decreased CACNb2 expression in SQTS cells. Quinidine prolonged the APD and abolished arrhythmic activity.

Conclusions

Patient-specific hiPSC-CMs are able to recapitulate single-cell phenotype features of SQTS type 5 and provide novel opportunities to further elucidate the cellular disease mechanism and test drug effects.

Funding Acknowledgement

Type of funding source: None

Abscisic acid and hydrogen peroxide are involved in drought priming-induced drought tolerance in wheat (Triticum aestivum L.)

Drought is one of the major stress factors in wheat production on a global scale. Drought priming during the early growth stage can enhance drought tolerance in wheat (Triticum aestivum L.). Abscisic acid (ABA) and hydrogen peroxide (H₂ O₂ ) are important signal molecules in the adaptation of plants to drought stress. However, the roles of ABA and H₂ O₂ in drought priming-induced drought tolerance are not clear. In the present study, we evaluated the responses of wheat to an ABA inhibitor, H₂ O₂ scavenger and an inhibitor to investigate the (i) relationship between ABA and H₂ O₂ in osmotic adjustment after drought priming in the vegetative stage and (ii) responses to drought stress during grain filling. In the drought priming alone treatments, chemical application resulted in the scavenging of ABA and H₂ O₂ , weakening the alleviation effects of drought priming on drought stress, as demonstrated by the lower leaf water potential and grain yield. The ABA inhibitor completely inhibited accumulation of ABA and H₂ O₂ ; the ABA inhibitor inhibited respiratory burst oxidase homologue expression, whereas the H₂ O₂ inhibitor resulted in higher 9-cis-epoxycarotenoid dioxygenase expression and ABA concentration in primed plants, indicating that ABA scavenging inhibited H₂ O₂ biosynthesis while H₂ O₂ scavenging did not inhibit ABA biosynthesis. The results further demonstrated that NADPH oxidase-mediated H₂ O₂ production functions downstream of ABA, which induces osmolyte transcript expression and accumulation, and thus contributes to drought priming-induced stress tolerance. These results provide a theoretical basis for a better understanding of the mechanisms involved in drought priming-induced tolerance in wheat plants.

Maximizing the accuracy of finite element simulation of elastic wave propagation in polycrystals

Three-dimensional finite element (FE) modelling, with representation of materials at grain scale in realistic sample volumes, is capable of accurately describing elastic wave propagation and scattering within polycrystals. A broader and better future use of this FE method requires several important topics to be fully understood, and this work presents studies addressing this aim. The first topic concerns the determination of effective media parameters, namely, scattering induced attenuation and phase velocity, from measured coherent waves. This work evaluates two determination approaches, through-transmission and fitting, and it is found that these approaches are practically equivalent and can thus be used interchangeably. For the second topic of estimating modelling errors and uncertainties, this work performs thorough analytical and numerical studies to estimate those caused by both FE approximations and statistical considerations. It is demonstrated that the errors and uncertainties can be well suppressed by using a proper combination of modelling parameters. For the last topic of incorporating FE model information into theoretical models, this work presents elaborated investigations and shows that to improve agreement between the FE and theoretical models, the symmetry boundary conditions used in FE models need to be considered in the two-point correlation function, which is required by theoretical models.

Dental nerves: a neglected mediator of pulpitis

As one of the most densely innervated tissues, the dental pulp contains abundant nerve fibres, including sensory, sympathetic and parasympathetic nerve fibres. Studies in animal models and human patients with pulpitis have revealed distinct alterations in protein expression and histological appearance in all types of dental nerve fibres. Various molecules secreted by neurons, such as classical neurotransmitters, neuropeptides and amino acids, not only contribute to the induction, sensitization and maintenance of tooth pain, but also regulate non-neuronal cells, including fibroblasts, odontoblasts, immune cells and vascular endothelial cells. Dental nerves are particularly important for the microcirculatory and immune responses in pulpitis via their release of a variety of functional substances. Further, nerve fibres are found to be involved in dental soft and hard tissue repair. Thus, understanding how dental nerves participate in pulpitis could have important clinical ramifications for endodontic treatment. In this review, the roles of dental nerves in regulating pulpal inflammatory processes are highlighted and their implications for future research on this topic are discussed.