A functional tacrolimus-releasing nerve wrap for enhancing nerve regeneration following surgical nerve repair

Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong disability.Currently,there are no FDA-approved therapies available to promote nerve regeneration.Tacrolimus accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve surgery.The authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug exposure.Tacrolimus is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 days.Size and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible byproducts.Tacrolimus released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic delivery.Given its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.

Ventricular Arrhythmia in the Fontan Circulation:Prevalence,Risk Factors and Clinical Implications

Objective:Sudden cardiac death(SCD)and malignant ventricular arrhythmia(VA)are increasingly recognized as important issues for people living with a Fontan circulation,but data are lacking.We sought to characterize the cohort who had sudden cardiac death,most likely related to VA and/or documented VA in the Australia and New Zealand Fontan Registry including risk factors and clinical outcomes.Methods:A retrospective cohort study was performed.Inclusion criteria were documented non-sustained ventricular tachycardia,sustained ventricular tachycardia,ventricular fibrillation,resuscitated cardiac arrest or SCD>30 days post-Fontan completion.Results:Of 1611 patients,20(1.2%)had VA;14(1.0%)had VA without SCD and 6(<1%)had SCD(6%of all deaths recorded in Registry;5 of those had documented VA at the time of arrest and 1 was presumed to be VA-associated).The median age at first VA was 20.5(14–32)years,10(50%)were females,and the median age at Fontan operation was 8(4–17)years.On univariable analysis,hypoplastic left heart syndrome(p=0.03)and older age Fontan operation(p<0.001)were associated with VA.Earlier Fontan era(p<0.003),atriopulmonary Fontan(p<0.001),pre-Fontan atrioventricular valve repair(p=0.013)pre-or post-Fontan atrial arrhythmia(p=0.010)were associated with SCD.Patients with VA had a 3 times higher risk of death or heart transplant(HR 3.27(1.19,8.98),p=0.02).Conclusions:A proportion of people living with a Fontan circulation have malignant VA.Routine VA screening in this cohort is essential.More data are needed to aid risk stratification.

Androgen abuse in sports

Androgens remain the most effective and widely abused ergogenic drugs in sport. Although androgen doping has been prohibited for over 3 decades with a ban enforced by mass spectrometric （MS）-based urine testing for synthetic and exogenous natural androgens, attempts continue to develop increasingly complex schemes to circumvent the ban. A prominent recent approach has been the development of designer androgens. Such never-marketed androgens evade detection because mass spectrometry relies on identifying characteristic chemical signatures requiring prior knowledge of chemical structure. Although once known, designer androgens are readily detected and added to the Prohibited List. However, until their structures are elucidated, designer androgens can circumvent the ban on androgen doping. To combat this, in vitro androgen bioassays offer powerful new possibilities for the generic detection of unidentified bioactive androgens, regardless of their chemical structure. Another approach to circumvent the ban on androgen doping has been the development of indirect androgen doping, the use of exogenous drugs to produce a sustained increase in endogenous testosterone （T） production. Apart from estrogen blockers, however, such neuroendocrine active drugs mostly provide only transient increases in blood T. Finally the ban on androgen doping must allow provision for rare athletes with incidental, proven androgen deficiency who require T replacement therapy. The Therapeutic Use Exemption mechanism makes provision for such necessary medical treatment, subject to rigorous criteria for demonstrating a genuine ongoing need for T and monitoring of T dosage. Effective deterrence of sports doping requires novel, increasingly sophisticated detection options calibrated to defeat these challenges, without which fairness in sport is tarnished and the social and health idealization of sporting champions devalued.

High-density lipoproteins:an emerging target in the prevention of cardiovascular disease

High-density lipoproteins （HDLs） have been well established to protect against the development of atherosclerotic cardiovascular disease. It has become apparent that in addition to the promotion of reverse cholesterol transport, HDLs possess a number of additional functional properties that may contribute to their beneficial influence on the arterial wall. A number of exciting therapeutic strategies have been developed that target HDL and its ability to protect against the development of atherosclerotic plaque. This paper will review how the promotion of the functional properties of HDL inhibits the formation of atherosclerotic plaque and stabilises lesions in patients with established disease.

Enhancing endothelial progenitor cell for clinical use

Circulating endothelial progenitor cells(EPCs) have been demonstrated to correlate negatively with vascularendothelial dysfunction and cardiovascular risk factors. However, translation of basic research into the clinical practice has been limited by the lack of unambiguous and consistent definitions of EPCs and reduced EPC cell number and function in subjects requiring them for clinical use. This article critically reviews the definition of EPCs based on commonly used protocols, their value as a biomarker of cardiovascular risk factor in subjects with cardiovascular disease, and strategies to enhance EPCs for treatment of ischemic diseases.

Dietary advanced glycation end-products aggravate non-alcoholic fatty liver disease

AIM To determine if manipulation of dietary advanced glycation end product(AGE), intake affects nonalcoholic fatty liver disease(NAFLD) progression and whether these effects are mediated via RAGE. METHODS Male C57Bl6 mice were fed a high fat, high fructose, high cholesterol(HFHC) diet for 33 wk and compared with animals on normal chow. A third group were given a HFHC diet that was high in AGEs. Another group was given a HFHC diet that was marinated in vinegar to prevent the formation of AGEs. In a second experiment, RAGE KO animals were fed a HFHC diet or a high AGE HFHC diet and compared with wildtype controls. Hepatic biochemistry, histology, picrosirius red morphometry and hepatic mR NA were determined. RESULTS Long-term consumption of the HFHC diet generated significant steatohepatitis and fibrosis after 33 wk. In this model, hepatic 4-hydroxynonenal content(a marker of chronic oxidative stress), hepatocyte ballooning, picrosirius red staining, α-smooth muscle actin and collagen type 1A gene expression were all significantly increased. Increasing the AGE content of the HFHC diet by baking further increased these markers of liver damage, but this was abrogated by pre-marination in acetic acid. In response to the HFHC diet, RAGE-/-animals developed NASH of similar severity to RAGE+/+ animals but were protected from the additional harmful effects of the high AGE containing diet. Studies in isolated Kupffer cells showed that AGEs increase cell proliferation and oxidative stress, providing a likely mechanism through which these compounds contribute to liver injury. CONCLUSION In the HFHC model of NAFLD, manipulation of dietary AGEs modulates liver injury, inflammation, and liver fibrosis via a RAGE dependent pathway. This suggests that pharmacological and dietary strategies targeting the AGE/RAGE pathway could slow the progression of NAFLD.

秋水仙碱(0.5mg 2次/d)对稳定性冠状动脉疾病患者高敏C-反应蛋白的影响(独立于阿司匹林和阿托伐他汀)

炎性标记物水平升高是稳定性冠状动脉疾病患者未来发生血管事件的预测因素,其中包括高敏C-反应蛋白(hs-CRP)≥2.0m g/L。长期使用小剂量秋水仙碱是缓解炎症的一种安全有效的措施,因此作者进行此项开放性初步研究,以探讨在采用阿司匹林联合大剂量阿托伐他汀治疗、hs-CRP≥2.0m g/L的稳定性冠状动脉疾病患者中,秋水仙碱能否显著降低hs-CRP水平。

Alcohol consumption in relation to the incidence of atrial fibrillation in an elderly Chinese population

BACKGROUND Alcohol consumption is a known modifiable risk factor for atrial fibrillation.The association,however,might differ according to gender.We investigated gender-specific associations between alcohol consumption and incident atrial fibrillation in an elderly Chinese population.METHODS Our study participants were elderly residents(≥65 years)recruited from five community health centers in the urban area of Shanghai(n=6,618).Alcohol intake was classified as never drinkers and current light-to-moderate(<40 g/day)and heavy drinkers(≥40 g/day).Atrial fibrillation was detected by a 30-s single-lead electrocardiography(ECG,AliveCor®Heart Monitor)and further evaluated with a regular 12-lead ECG.RESULTS During a median of 2.1 years(interquartile range:2.0−2.2)follow-up,the incidence rate of atrial fibrillation was 1.10%in all study participants.It was slightly but non-significantly higher in men(n=2849)than women(n=3769,1.30%vs.0.96%,P=0.19)and in current drinkers(n=793)than never drinkers(n=5825,1.64%vs.1.03%,P=0.12).In both unadjusted and adjusted analyses,there was interaction between sex and current alcohol intake in relation to the incidence of atrial fibrillation(P<0.0001).After adjustment for confounding factors,current drinkers had a significantly higher incidence rate of atrial fibrillation than never drinkers in women(12.96%[7/54]vs.0.78%[29/3715],adjusted odds ratio[OR]=10.25,95%confidence interval[CI]:3.54−29.67,P<0.0001),but not in men(0.81%[6/739]vs.1.47%[31/2110],OR=0.62,95%CI:0.25−1.51,P=0.29).CONCLUSIONS Our study showed a significant association between alcohol intake and the incidence of atrial fibrillation in elderly Chinese women,but not men.

β_2、β_3肾上腺素能受体功能多态性与5年后体重增加和血压升高相关

Background-The genes responsible for obesity are candidate genes for obesity-related diseases, such as hypertension. Functional polymorphisms in the β2-and β3-adrener-gic receptors have been reported to be associated with hypertension and obesity. Methods and Results-To longitudinally clarify the relevance to alterations in β-adrenergic receptor polymorphisms related to weight gain, blood pressure(BP) elevation, and sympathetic nerve activity as measured by plasma norepinephrine level, we studied 160 young, nonobese, normotensive men. Changes in body weight, BP, plasma norepinephrine levels, and β2-adrenergic(Arg16Gly, Gln27Glu) and β3-adrenergic(Trp64Arg) receptor polymorphisms were measured periodically over a 5-year period. Weight gain and BP elevation were defined as ≥10%increases from entry levels over 5 years in body mass index or mean BP. The presence of the Gly16 allele of Arg16Gly was associated with a higher frequency of weight gain and BP elevation over the 5-year period. The subjects carrying the Glu27 allele of Gln27Glu and the Trp64 allele of Trp64Arg had a higher frequency of BP elevation. Significantly higher levels of plasma norepinephrine at entry and at year 5 were observed in the subjects with the Gly16 allele of Arg16Gly and the Glu27 allele of Gln27Glu compared with those without the Gly16 or the Glu27 alleles. Conclusions-These results demonstrate that the Gly16 allele is related to greater weight gain and BP elevation. Additionally, Glu27 and Trp64 alleles are linked to BP elevation. The subjects carrying the β2-polymorphisms linked to weight gain and BP elevation also have higher plasma norepinephrine levels that are present at entry before weight gain and BP elevation. These findings suggest that β2-adrenergic receptor polymorphisms in association with a heightened sympathetic nerve activity could predict the future onset of obesity and hypertension, as shown in the 5-year longitudinal study.

A comprehensive cardiotoxicity assay by combining high-throughput multiple ion channel screening with human cardiomyocyte-based action potential validation

OBJECTIVE Cardiotoxicity refers to drug-induced arrhythmia such as Torsades de pointes.Current single ion channel(hERG)-based assay generates-30% false results.The aim is to establish an advanced in vitro cardiotoxicity assay by incorporating high throughput multiple cardiac ion channel screening and human cardiomyocytes-based validation.METHODS Effects of drugs were tested on multiple cell lines expressing hERG,Nav1.5 and Cav1.2 by automated patch clamping.Subsequently,the results were validated with human pluripotent stem cell(hPSC)-derived cardiomyocytes(hPSC-CMs)in which ion currents and action potentials were measured by manual patch clamping.RESULTS We have tested the cardiotoxicity of monomers extracted from various medical herbs.Mitragynine is the major bioactive compound isolated from kratom,a therapeutic herb from the rain forest of South East Asia.As a popular stimulant,it has been associated with a number of acute fatal incidences.We observed a typical torsadogenic hazard of mitragynine.It exerted a strong hERG inhibition in hERG-HEK293 cell line(IC50:5.2 μmol·L-1)and hPSC-CMs(IC50:0.91 μmol·L-1)without affecting other cardiac ion channels.Moreover,it caused a significant prolongation of action potential duration(APD)in hPSC-CMs(a-32.5%increase in APD at 50 and 90%repolarization).On the other hand,deoxylelephantopin,apotential anti-cancer reagent,demonstrated low cardiotoxicity.It exerted a week inhibition on hERG in HEK293 cells with an IC50 of 87.2 μmol·L-1,while the effective concentrations for suppressing the growth of cancer cells ranges from 2 to 20μmol·L-1.At 100μmol·L-1,deoxylelephantopin showed no effects on Cav1.2 and Nav1.5 and it failed to alter APD in hPSC-CMs.CONCLUSION We have successfully tested a newin vitro cardiotoxicity assay strategy which incorporates multiple cardiac ion channels screening and hPSC-CMs validation.This new strategy could facilitate the effective and efficient evaluation of existing and new drugs/reagents for potential pro-arrhythmic risk.

Knowledge,attitude and perception of antiplatelet therapy among dentists in Central Eastern Turkey

AIM:To survey the dentists in Central Eastern Turkey,testing their knowledge on coronary interventions and assessing perception of antecedent dual antiplatelet therapy.METHODS:Two hundred and ninety-eight dentists were surveyed face-to-face by completing questionnaires,including 16 structured questions focused on general knowledge of coronary stents,and assessing periprocedural practice with regard to antiplatelet therapy.RESULTS:All respondents were aware of such devices as coronary stents,but only one-third of the respondents knew the differences between a bare metal and a drug-eluting stent design,and associated vascularoutcomes.Awareness about stent thrombosis was limited to 34%,while consequences of interrupting antiplatelet therapy were known to only 30% of surveyed dentists.Importantly,the attitudes of surveyed respondents differed substantially depending on the location of their practice,where dentists working in the urban environment(population over 10 000) were more aware of antiplatelet recommendations when compared to their colleagues from the rural areas.CONCLUSION:Knowledge about coronary stents,associated clinical outcomes,and current guidelines with regard to surgical management of antecedent antiplatelet therapy in Central Eastern Turkey is inconsistent,and heavily dependent on the location of dental practice.Rural areas around the globe should be in a focus of continuous medical education to improve the quality of medical care.

<i>In Pursuit</i>of Porcine Pluripotent Stem Cells for Autologous Cell Therapy

Treatments to repair the human heart following regenerative diseases remain a challenge for medical science. Unlike lower vertebrate species the human heart lacks a regenerative pathway meaning that research has to be focused on cell transplantation. Porcines (Sus scrofa) are excellent models for cardiovascular disease and pluripotent stem cells (PSCs) generated from porcines will provide important clinical insights for cardiac cell therapy. This could open a new avenue of research into degenerative conditions as porcine is a more effective human proxy to work with. However, bona fide PSCs are currently available onlyin rodents (mouse, rat) and primates (monkey, human). Attempts to derivepluripotent stem cells (PSCs) from porcine have been going on for more than two decades with slow progress. Despite the fact that the porcine stem cells are under increasing glare of publicity due to milestone achievements in this area of research. Advances in stem cell technology, especially the genetic engineering, innovative cell culturing and induced pluripotency to generate stem cells has dramatically revolutionized the basic and applied investigations and applications of porcine stem cells. This review attempts to summarize the major signaling pathways involved in maintenance of pluripotency and the state of the art conceptual and technical progress for generating bona fide porcine PSCs.

高血压患者和血压正常的遗传性易感人群其L-精氨酸转运和内皮功能受损

Background-Impaired endothelium-dependent NO-mediated vasodilation is a key feature of essential hypertension and may precede the increase in blood pressure. We investigated whether transport of the NO precursor L-arginine is related to decreased endothelial function. Methods and Results-Radiotracer kinetics([3H]L-arginine)were used to measure forearm and peripheral blood mononuclear cell arginine uptake in hypertensive subjects(n=12)and in 2 groups of healthy volunteers with(n=15)and without(n=15)a family history of hypertension. In conjunction, forearm blood flow responses to acetylcholine and sodium nitroprusside were measured before and after a supplemental intra-arterial infusion of L-arginine. In vivo and in vitro measures of L-arginine transport were substantially reduced in the essential hypertension and positive family history groups compared with the negative family history group; however, no difference was detected in peripheral blood mononuclear cell mRNA or protein expression levels for the cationic amino acid transporter CAT-1. Plasma concentrations of L-arginine and NG,NG-dimethylarginine(ADMA)did not differ between groups. L-Arginine supplementation improved the response to acetylcholine only in subjects with essential hypertension and positive family history. Conclusions-Similar to their hypertensive counterparts, normotensive individuals at high risk for the development of hypertension are characterized by impaired L-arginine transport, which may represent the link between a defective L-arginine/NO pathway and the onset of essential hypertension. The observed transport defect is not due to apparent alterations in CAT-1 expression or elevated endogenous ADMA.

雷米普利显著改善外周动脉疾病患者的行走能力:一项随机试验

背景:50岁以上成人中12%受到外周动脉疾病(PAD)的影响。传统治疗方法仅能稍稍改善症状。目的:观察血管紧张素转换酶抑制剂对PAD患者行走能力的影响。设计:一项随机、双盲、安慰剂对照的临床试验,始于2003年3月,终止于2005年1月。

Harnessing the power of bioprinting for the development of next-generation models of thrombosis

Thrombosis,a leading cause of cardiovascular morbidity and mortality,involves the formation of blood clots within blood vessels.Current animal models and in vitro systems have limitations in recapitulating the complex human vasculature and hemodynamic conditions,limiting the research in understanding the mechanisms of thrombosis.Bioprinting has emerged as a promising approach to construct biomimetic vascular models that closely mimic the structural and mechanical properties of native blood vessels.This review discusses the key considerations for designing bioprinted vascular conduits for thrombosis studies,including the incorporation of key structural,biochemical and mechanical features,the selection of appropriate biomaterials and cell sources,and the challenges and future directions in the field.The advancements in bioprinting techniques,such as multimaterial bioprinting and microfluidic integration,have enabled the development of physiologically relevant models of thrombosis.The future of bioprinted models of thrombosis lies in the integration of patient-specific data,real-time monitoring technologies,and advanced microfluidic platforms,paving the way for personalized medicine and targeted interventions.As the field of bioprinting continues to evolve,these advanced vascular models are expected to play an increasingly important role in unraveling the complexities of thrombosis and improving patient outcomes.The continued advancements in bioprinting technologies and the collaboration between researchers from various disciplines hold great promise for revolutionizing the field of thrombosis research.

Skin 11β-hydroxysteroid dehydrogenase type 1 enzyme expression regulates burn wound healing and can be targeted to modify scar characteristics

Background:Excessive scarring and fibrosis are the most severe and common complications of burn injury.Prolonged exposure to high levels of glucocorticoids detrimentally impacts on skin,leading to skin thinning and impaired wound healing.Skin can generate active glucocorticoids locally through expression and activity of the 11β-hydroxysteroid dehydrogenase type 1 enzyme(11β-HSD1).We hypothesised that burn injury would induce 11β-HSD1 expression and local glucocorticoid metabolism,which would have important impacts on wound healing,fibrosis and scarring.We additionally proposed that pharmacological manipulation of this system could improve aspects of post-burn scarring.Methods:Skin 11β-HSD1 expression in burns patients and mice was examined.The impacts of 11β-HSD1 mediating glucocorticoid metabolism on burn wound healing,scar formation and scar elas-ticity and quality were additionally examined using a murine 11β-HSD1 genetic knockout model.Slow-release scaffolds containing therapeutic agents,including active and inactive glucocorticoids,were developed and pre-clinically tested in mice with burn injury.Results:We demonstrate that 11β-HSD1 expression levels increased substantially in both human and mouse skin after burn injury.11β-HSD1 knockout mice experienced faster wound healing than wild type mice but the healed wounds manifested significantly more collagen deposition,tensile strength and stiffness,features characteristic of excessive scarring.Application of slow-release prednisone,an inactive glucocorticoid,slowed the initial rate of wound closure but significantly reduced post-burn scarring via reductions in inflammation,myofibroblast generation,collagen production and scar stiffness.Conclusions:Skin 11β-HSD1 expression is a key regulator of wound healing and scarring after burn injury.Application of an inactive glucocorticoid capable of activation by local 11β-HSD1 in skin slows the initial rate of wound closure but significantlyimproves scar characteristics post burn injury.

Movable typing of full-lumen personalized Vein-Chips to model cerebral venous sinus thrombosis

Cerebral venous sinus thrombosis(CVST)is a type of stroke associated with COVID-19 vaccine-induced immune thrombotic thrombocytopenia.The precise etiology of CVST often remains elusive due to the highly heterogeneous nature of its governing mechanisms,specifically,Virchow’s triad that involves altered blood flow,endothelial dysfunction,and hypercoagulability,which varies substantially amongst individuals.Existing diagnostic and monitoring approaches lack the capability to reflect the combination of these patient-specific thrombotic determinants.In response to this challenge,we introduce a Vein-Chip platform that recapitulates the CVST vascular anatomy from magnetic resonance venography and the associated hemodynamic flow profile using the“Chinese Movable Type-like”soft stereolithography technique.The resultant full-lumen personalized Vein-Chips,functionalized with endothelial cells,enable in-vitro thrombosis assays that can elucidate distinct thrombogenic scenarios between normal vascular conditions and those of endothelial dysfunction.The former displayed minimal platelet aggregation and negligible fibrin deposition,while the latter presented significant fibrin extrusion from platelet aggregations.The low-cost movable typing technique further enhances the potential for commercialization and broader utilization of personalized Vein-Chips in surgical labs and at-home monitoring.Future research and development in this direction will pave the way for improved management and prevention of CVST,ultimately benefiting both patients and healthcare systems.

Biomechanical thrombosis: the dark side of force and dawn of mechano-medicine

Arterial thrombosis is in part contributed by excessive platelet aggregation,which can lead to blood clotting and subsequent heart attack and stroke.Platelets are sensitive to the haemodynamic environment.Rapid haemodynamcis and disturbed blood flow,which occur in vessels with growing thrombi and atherosclerotic plaques or is caused by medical device implantation and intervention,promotes platelet aggregation and thrombus formation.In such situations,conventional antiplatelet drugs often have suboptimal efficacy and a serious side effect of excessive bleeding.Investigating the mechanisms of platelet biomechanical activation provides insights distinct from the classic views of agonist-stimulated platelet thrombus formation.In this work,we review the recent discoveries underlying haemodynamic force-reinforced platelet binding and mechanosensing primarily mediated by three platelet receptors:glycoprotein Ib(GPIb),glycoprotein IIb/IIIa(GPIIb/IIIa)and glycoprotein VI(GPVI),and their implications for development of antithrombotic‘mechano-medicine’.