Purpose Chemical exchange saturation transfer(CEST)imaging is used to study the changes of glutamate metabolism in the hippocampus of rats with chronic unpredictable mild stress(CUMS)model,so as to evaluate the clinical reference value of glutamate acid CEST(GluCEST)imaging results.Materials and Methods Twenty-two male SD rats were enrolled,and were divided into CUMS and healthy groups.Rats in CUMS group were further divided into the non-treatment group(n=7)and the ketamine treatment group(n=8).Seven healthy rats were randomly selected as control group.CEST imaging scans were performed using 7T small animal magnetic resonance and glutamate concentrations were measured in both hippocampi.The difference of hippocampal GluCEST value and glutamate concentration between control group and CUMS non-treatment group,CUMS ketamine treatment group and CUMS non-treatment group was analyzed,respectively.Results Compared with the control group,the hippocampal GluCEST value in CUMS non-treatment group was increased(left:t=2.8,P=0.015;right:t=3.0,P=0.011),while the hippocampal GluCEST value of rats in CUMS ketamine treatment group was decreased compared with CUMS non-treatment group(left:t=2.3,P=0.037;right:t=2.5,P=0.028).Conclusion GluCEST imaging can provide high spatial resolution images and accurately evaluate the changes of glutamate metabolism in hippocampus of rats with depression,which is conducive to monitoring the abnormal signals of hippocampal neurons caused by depression.

The incidence of vascular diseases is extremely high and mechanical stress plays an important role in vascular remodeling.Reactive oxygen species(ROS)at physiological levels modulate cell signaling while excessive ROS trigger oxidative stress and induce injury.The types of mechanical stresses in the vascular system and the sources of ROS are summarized.Besides,the roles and mechanisms of mechanical stress-induced oxidative stress in vascular diseases are discussed.This review will facilitate a deeper understanding of vascular activity and disease development at the molecular level,provide potential targets for treating vascular diseases.In addition,there are still research gaps on the mechanism of oxidative stress induced by mechanical stress in vascular diseases.Therefore,the potential research direction of mechanical stress-induced oxidative stress in the vascular system is also predicted,with the aim to promote the development of mechanobiology to a certain extent.

Objective To explore the role of Piezo2 in venous vascular smooth muscle cell(VSMC)dysfunction and neointimal hyperplasia following exposure of veins to an arterial mechanical environment,and elucidate its potential role in venous restenosis after coronary artery bypass grafting(CABG)and arteriovenous fistula(AVF)surgery.Methods Based on transcriptomic datasets,differentially expressed genes between AVF or grafted veins with normal veins were analyzed using GEO2R and GO.Immunofluorescence was used to detect expression of Piezo2 in two AVF clinical samples.The FX-5000TM cyclic stretch application system was used to apply 1.25 Hz stretch with 15%amplitude to VSMCs to simulate arterial conditions in vitro.The protein expressions of Piezo2,SM22(VSMC phenotypic marker),and PCNA(proliferation-related molecule)were measured with Western Blot.The calcium-free medium was further used to remove extracellular Ca2+,and the effect of Ca2+on stretch-induced changes in related molecules were analyzed.Results Transcriptomic analysis revealed that Piezo2 was upregulated in AVF and grafted veins compared to normal veins.Immunofluorescence showed the increased protein expression of Piezo2 in AVF tissues compared to normal veins.Notably,in the neointimal tissue of AVF samples,Piezo2 was significantly upregulated,while SMA was downregulated.In vitro,15%cyclic stretch upregulated Piezo2 and PCNA expression but downregulated SM22 expression,which suggested a phenotypic switch of venous VSMCs from the contractile phenotype to the synthetic phenotype.Removal of extracellular Ca2+partially reversed the stretch-induced VSMC phenotypic switch and proliferation.Conclusions After veins are exposed to an arterial mechanical environment,the upregulated Piezo2 may induce neointimal hyperplasia by promoting VSMC phenotypic switch.This study may provide mechanobiological insights and potential therapeutic targets for the prevention and treatment of venous restenosis following CABG and AVF surgeries.

Objective To explore the role of Piezo2 in venous vascular smooth muscle cell(VSMC)dysfunction and neointimal hyperplasia following exposure of veins to an arterial mechanical environment,and elucidate its potential role in venous restenosis after coronary artery bypass grafting(CABG)and arteriovenous fistula(AVF)surgery.Methods Based on transcriptomic datasets,differentially expressed genes between AVF or grafted veins with normal veins were analyzed using GEO2R and GO.Immunofluorescence was used to detect expression of Piezo2 in two AVF clinical samples.The FX-5000TM cyclic stretch application system was used to apply 1.25 Hz stretch with 15%amplitude to VSMCs to simulate arterial conditions in vitro.The protein expressions of Piezo2,SM22(VSMC phenotypic marker),and PCNA(proliferation-related molecule)were measured with Western Blot.The calcium-free medium was further used to remove extracellular Ca2+,and the effect of Ca2+on stretch-induced changes in related molecules were analyzed.Results Transcriptomic analysis revealed that Piezo2 was upregulated in AVF and grafted veins compared to normal veins.Immunofluorescence showed the increased protein expression of Piezo2 in AVF tissues compared to normal veins.Notably,in the neointimal tissue of AVF samples,Piezo2 was significantly upregulated,while SMA was downregulated.In vitro,15%cyclic stretch upregulated Piezo2 and PCNA expression but downregulated SM22 expression,which suggested a phenotypic switch of venous VSMCs from the contractile phenotype to the synthetic phenotype.Removal of extracellular Ca2+partially reversed the stretch-induced VSMC phenotypic switch and proliferation.Conclusions After veins are exposed to an arterial mechanical environment,the upregulated Piezo2 may induce neointimal hyperplasia by promoting VSMC phenotypic switch.This study may provide mechanobiological insights and potential therapeutic targets for the prevention and treatment of venous restenosis following CABG and AVF surgeries.

Purpose Chemical exchange saturation transfer(CEST)imaging is used to study the changes of glutamate metabolism in the hippocampus of rats with chronic unpredictable mild stress(CUMS)model,so as to evaluate the clinical reference value of glutamate acid CEST(GluCEST)imaging results.Materials and Methods Twenty-two male SD rats were enrolled,and were divided into CUMS and healthy groups.Rats in CUMS group were further divided into the non-treatment group(n=7)and the ketamine treatment group(n=8).Seven healthy rats were randomly selected as control group.CEST imaging scans were performed using 7T small animal magnetic resonance and glutamate concentrations were measured in both hippocampi.The difference of hippocampal GluCEST value and glutamate concentration between control group and CUMS non-treatment group,CUMS ketamine treatment group and CUMS non-treatment group was analyzed,respectively.Results Compared with the control group,the hippocampal GluCEST value in CUMS non-treatment group was increased(left:t=2.8,P=0.015;right:t=3.0,P=0.011),while the hippocampal GluCEST value of rats in CUMS ketamine treatment group was decreased compared with CUMS non-treatment group(left:t=2.3,P=0.037;right:t=2.5,P=0.028).Conclusion GluCEST imaging can provide high spatial resolution images and accurately evaluate the changes of glutamate metabolism in hippocampus of rats with depression,which is conducive to monitoring the abnormal signals of hippocampal neurons caused by depression.

The incidence of vascular diseases is extremely high and mechanical stress plays an important role in vascular remodeling.Reactive oxygen species(ROS)at physiological levels modulate cell signaling while excessive ROS trigger oxidative stress and induce injury.The types of mechanical stresses in the vascular system and the sources of ROS are summarized.Besides,the roles and mechanisms of mechanical stress-induced oxidative stress in vascular diseases are discussed.This review will facilitate a deeper understanding of vascular activity and disease development at the molecular level,provide potential targets for treating vascular diseases.In addition,there are still research gaps on the mechanism of oxidative stress induced by mechanical stress in vascular diseases.Therefore,the potential research direction of mechanical stress-induced oxidative stress in the vascular system is also predicted,with the aim to promote the development of mechanobiology to a certain extent.

Objective To investigate the effect of pathologically elevated-cyclic stretch induced by hypertension on mitochondrial biogenesis of vascular smooth muscle cells (VSMCs), and the role of PGC1α in this process. Methods The Flexcell-5000T stretch loading system in vitro was applied to VSMCs with a frequency of 1. 25 Hz and an amplitude of 5% or 15% to simulate the mechanical environment under normal physiological or hypertensive pathological conditions respectively. Western blotting and qPCR were used to detect the expression of PGC1α, citrate synthase and mitochondrial DNA (mtDNA) copy number in VSMCs under normal physiological or hypertensive pathological conditions. VSMCs were treated with PGC1α specific activator ZLN005 to promote PGC1α expression or specific interfering fragment siRNA to inhibit PGC1α expression in order to detect the effect on citrate synthase and mtDNA copy number. Results Compared with 5% physiological cyclic stretch, 15% pathologically elevated-cyclic stretch significantly suppressed the expression of PGC1α, citrate synthase and mtDNA copy number in VSMCs. Compared with control group, the protein expression of PGC1α was significantly decreased and increased respectively. When VSMCs transfected with PGC1α siRNA or incubated PGC1α activator ZLN005, the expression of citrate synthase and mtDNA copy number were also significantly down regulated and up-regulated in VSMCs accordingly. Under physiological cyclic stretch conditions, the protein level of PGC1α was significantly down-regulated by PGC1α siRNA, which also significantly down-regulated citrate synthase expression and mtDNA copy number. The protein expression of PGC1α was significantly up-regulated by ZLN005, which also enhanced the expression of citrate synthase and mtDNA copy number. Conclusions The pathological cyclic stretch induced by hypertension significantly down-regulated the expression of citrate synthase and mtDNA copy number via suppressing the expression of PGC1α, resulting in mitochondrial dysfunction of VSMCs. PGC1α may be a potential therapeutic target molecule to alleviate the progression of hypertension.

Objective To investigate the effects of cyclic stretch on migration of MC3T3-E1 cells and its related mechanism. Methods The strain loading system was used to stretch MC3T3-E1 cells cultured in vitro with 15% amplitude, to simulate the mechanical condition in vivo. The wound healing assay was used to detect the migration of MC3T3-E1 cells. Western blotting was used to test Runx2 expression. RNA interfering was used to decrease Runx2 expression. Results Cyclic mechanical stretch with 15% amplitude, 1.25 Hz frequency and lasting for 24 hours could promote the migration of MC3T3-E1 cells and increase the expression level of Runx2. Runx2 interference inhibited the migration of MC3T3-E1 cells in static culture condition. Interference with Runx2 expression in MC3T3-E1 cells could partially reduce the positive effect of cyclic mechanical stretch on cell migration. Conclusions Cyclic stretch can promote the migration of MC3T3-E1 cells, and Runx2 may play an important role in this process. This study provides experimental basis for finding innovative clinical treatment method to promote fracture healing.

Objective To explore the role of adenosine monophosphate-activated protein kinase (AMPK), a key regulator of cellular energy metabolism, in vascular smooth muscle cell (VSMC) migration in response to physiological cyclic stretch. Methods The Flexcell-5000T mechanical loading system was applied with a physiological cyclic stretch at 10% amplitude and 1.25 Hz frequency to primary rat VSMCs, to simulate mechanical stimulation of VSMCs in vivo. The protein expression of p-AMPK in VSMCs was detected by Western blotting, and VSMC migration was detected by wound healing test. Results Compared with the static group, physiological cyclic stretch loading for 24 h significantly decreased the area of wound healing, indicating that physiological cyclic stretch inhibited VSMC migration. The protein expression of p-AMPK in VSMCs was increased significantly after physiological cyclic stretch loading for 3 h, and was decreased significantly after 24 h. Under physiological cyclic stretch loading conditions, incubating AMPK inhibitor could significantly reduce the protein expression of p-AMPK after 3 h, and promote VSMC migration after 24 h; incubating AMPK activator AICAR under static conditions significantly increased the protein expression of p-AMPK after 3 h, and weakened VSMC migration after 24 h. Conclusions Physiological cyclic stretch inhibits VSMC migration by increasing the protein expression of p-AMPK, indicating that VSMC migration regulated by physiological cyclic stretch is of great significance for maintaining vascular homeostasis.

To report a typical case of Morvan syndrome with positive anti-leucine rich glioma-inactivated 1(LGI1) and contactin-associated protein 2 (CASPR2) antibodies in serum and cerebrospinal fluid. A 39-years-old female initially presented weakness of extremeties. The main symptoms included paroxysmal limb pain, wheezing, itching, muscle twitching, epilepsy, hypomnesia, dysphoria, apathy, intractable insomnia, salivation and sweating. Tests of electrolytes found hypokalemia (2.7-3.1 mmol/L) and hyponatremia (130-136 mmol/L). Arterial blood gas analysis showed hypoxemia (oxygen saturation 50%-70%). Total thyroxine (TT4) was elevated to 207 nmol/L with positive thyroid peroxidase antibody (TPO-Ab) and thyroglobulin antibody (TG-Ab). LGI1and CASPR2 antibodies (CBA method) were positive in both serum and cerebrospinal fluid, and the remaining antibodies related to autoimmune encephalitis and paraneoplastic syndrome were negative. Head MRI was almost normal, while mild abnormalities were found in electroencephalogram. Electromyography showed slightly increased voltage of left quadriceps motor unit potential. After treated with corticosteroids, IVIG and mycophenolate mofetil, the patient completely improved. Cognitive function scores recovered from MoCA/MMSE (16/24) to MoCA/MMSE (26/29). Positivity of LGI1/CASPR2 antibodies both in serum/cerebrospinal fluid are rarely seen in patients with Morvan syndrome. Steroids and immunosuppressants are suggested for treatment as early as possible.