Vascular Endothelial Cell Damage Research Articles

MasR and pGCA receptor activation protects primary vascular smooth muscle cells and endothelial cells against oxidative stress via inhibition of intracellular calcium.

Cardiovascular diseases (CVDs)are associated with vascular smooth muscle cell (VSMC)and endothelial cell (EC)damage. Angiotensin1-7 (Ang1-7) and B-type natriuretic peptide (BNP)are responsible for vasodilation and regulation of blood flow. These protective effects of BNP are primarily mediated by the activation of sGCs/cGMP/cGKIpathway. Conversely, Ang1-7 inhibits Angiotensin II-induced contraction and oxidative stress via Mas receptor activation. Thus, the aim of the study was to determine the effect of co-activation of MasR and particulate guanylate cyclase receptor (pGCA)pathways by synthesized novel peptide (NP)in oxidative stress-induced VSMCs and ECs. MTTand Griess reagent assay kits were used for the standardization of the oxidative stress (H2 O2 ) induced model in VSMCs. The expression of targeted receptors in VSMC was done by RT-PCRand Western blot analysis. Protective effect of NP in VSMC and EC was determined by immunocytochemistry, FACS analysis, and Western blot analysis. Underlying mechanisms of EC-dependent VSMC relaxation were done by determining downstream mRNA gene expression and intracellular calcium imaging of cells. Synthesized NP significantly improved oxidative stress-induced injury in VSMCs. Remarkably, the actions of NP were superior to that of the Ang1-7 and BNP alone. Further, a mechanistic study in VSMC and EC suggested the involvement of upstream mediators of calcium inhibition for the therapeutic effect.NP is reported to possess vascular protective activities and is also involved in the improvement of endothelial damage. Moreover, it is highly effective than that of individual peptides BNP and Ang1-7 and therefore it may represent a promising strategy for CVDs.

The activation of histone deacetylases 4 prevented endothelial dysfunction: A crucial mechanism of HuangqiGuizhiWuwu Decoction in improving microcirculation dysfunction in diabetes.

The regulation of epigenetic factors is considered a crucial target for solving complex chronic diseases such as cardio-cerebrovascular diseases. HuangqiGuizhiWuwu Decoction (HGWWD), a classic Chinese prescription, is mainly used to treat various vascular diseases. Although our previous studies reported that HGWWD could effectively prevent vascular dysfunction in diabetic rodent models, the precise mechanism is still elusive. In this study, we investigated the epigenetic mechanisms of modulating the damage of vascular endothelial cells in diabetes by HGWWD. We first analyzed common active components of HGWWD by using HPLC-Q-TOF-MS/MS analysis, and predicted the isoforms of histone deacetylase (HDAC) that can potentially combine the above active components by systems pharmacology. Next, we screened the involvement of specific HDAC isoforms in the protective effect of HGWWD on vascular injury by using pharmacological blockade combined with the evaluation of vascular function in vivo and in vitro. Firstly, HDAC1, HDAC2, HDAC3, HDAC4, HDAC6, HDAC7, SIRT2, and SIRT3 have been implicated with the possibility of binding to the thirty-one common active components in HGWWD. Furthermore, the protective effect of HGWWD is reversed by both TSA (HDAC inhibitor) and MC1568 (class II HDAC inhibitor) on vascular impairment accompanied by reduced aortic HDAC activity in STZ mice. Finally, inhibition of HDAC4 blocked the protective effect of HGWWD on microvascular and endothelial dysfunction in diabetic mice. These results prove the key role of HDAC4 in diabetes-induced microvascular dysfunction and underlying epigenetic mechanisms for the protective effect of HGWWD in diabetes.

Molecular Mechanism of Fucoidan Nanoparticles as Protector on Endothelial Cell Dysfunction in Diabetic Rats' Aortas.

Antioxidants have an important role in protecting against diabetes complications such as vascular endothelial cell damage. Fucoidan has strong antioxidant properties, therefore the aim of this study was to investigate the protective mechanism of fucoidan nanoparticles through the pathway of antioxidant activity against streptozotocin-induced diabetic aortic endothelial cell dysfunction in rats. Fucoidan nanoparticles are made utilizing high-energy ball milling. This research consists of five groups, namely: control rats, rats were administered aquadest; diabetic rats, rats were administered streptozotocin (STZ); fucoidan nanoparticle rats, rats were administered STZ and fucoidan nanoparticles. Aortic tissue was collected for the evaluation of ROS (reactive oxygen species), Malondialdehyde (MDA), superoxide Dismutase (SOD), Glutathione Peroxidase (GPx), Nuclear factor erythroid-2-related factor 2 (Nrf2), Nitric Oxide (NO), cyclic Guanosine Monophosphate (cGMP), relaxation response of acetylcholine (Ach), and the diameter of the aorta. The size distribution of the fucoidan nanoparticles was 267.2 ± 42.8 nm. Administration of fucoidan nanoparticles decreased the levels of ROS and MDA, and increased the levels of SOD, levels of GPx, Nrf2 expression, NO levels, cGMP expression, the relaxation response of Ach, and lumen diameter of the aorta, which are significantly different when compared with diabetic rats, p < 0.05. In this study, we concluded that the mechanism pathway of fucoidan nanoparticles prevents aortic endothelial cell dysfunction in diabetic rats through antioxidant activity by reducing ROS and MDA and incrementing SOD levels, GPx levels, and Nrf2 expression. All of these can lead to an elevated relaxation response effect of Ach and an increase in the lumen diameter of the aorta, which indicates a protective effect of fucoidan nanoparticles on aortic endothelial cells.

PS-BPB01-9: OMEGA-3 FATTY ACIDS ATTENUATE OXIDATIVE STRESS-INDUCED DNA DAMAGE THROUGH NRF-2 IN VASCULAR ENDOTHELIAL CELLS

Objective: Impaired vasodilation is one of the characterizations of hypertension. The effects of the omega-3 fatty acids on blood pressure and vascular function have been examined in many randomized controlled trials. In this study, we investigated the effects of omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on DNA damage, which has crucial effects on vascular endothelial cell function. Design and method: We examined the effects of EPA and DHA on H2O2-induced DNA damage response in human aortic endothelial cells (HAECs). DNA double-strand breaks (DSBs) were detected by immunofluorescence staining of the phosphorylated form of the histone H2AX (gamma-H2AX). Results: EPA and DHA significantly reduced accumulation of DSBs and phosphorylation of ATM, a serine/threonine kinase recruited and activated upon DSBs, in HAECs. Since EPA and DHA attenuated DNA damage without enhancement of DNA repair response, the effects of EPA and DHA on oxidative stress, a DNA damage inducer, were examined. CM-H2DCFDA measurement showed that EPA and DHA significantly reduced intracellular reactive oxygen species. In addition, mRNA levels of antioxidant molecules, such as heme oxygenase-1 and thioredoxin reductase 1, were significantly elevated by EPA and DHA. Silencing the gene encoding nuclear factor erythroid 2-related factor 2 (Nrf2) abrogated these increases. Furthermore, EPA and DHA reduced H2O2-induced senescence-associated beta-galactosidase activity, which was revoked by Nrf2 silencing. Conclusions: Our results suggest that EPA and DHA attenuate oxidative stress-induced DNA damage and cell senescence in vascular endothelial cells partly via antioxidant response mediated by Nrf-2. Therefore EPA and DHA may play a role in the prevention of impairment in vasodilation by their genome-protective properties.

Nanoplastic-induced vascular endothelial injury and coagulation dysfunction in mice

Nanoplastics are the persistent pollutants in a variety of environments, representing a potential threat to human health. Notably, plastic particles have been detected in sample of human bloodstream. It is thus significant to investigate the effects of nanoplastics on the cardiovascular system owing to its ease transfer through the bloodstream to other organs. However, few studies have been performed to evaluate the cardiovascular toxicity of nanoplastics. Herein, we pursued to investigate the adverse cardiovascular impacts of polystyrene (PS), PS-NH2 and PS-COOH nanoplastics on mice. Experimental results demonstrated that the exposure to these nanoplastics could result in structural damage of vascular endothelial cells and inflammatory response. Moreover, it was found out that the dysfunctions of coagulation and prethrombotic state were caused by nanoplastics, which could be ascribed to the activation of JAK1/STAT3/TF signaling pathway. In summary, results clearly indicated that nanoplastic exposure lead to vascular toxicity to mice, which serves as a basis for future studies about the potential physiological threat of nanoplastics to humans.

Statins Show Anti-Atherosclerotic Effects by Improving Endothelial Cell Function in a Kawasaki Disease-like Vasculitis Mouse Model.

Kawasaki disease (KD) is an acute inflammatory syndrome of unknown etiology that is complicated by cardiovascular sequelae. Chronic inflammation (vasculitis) due to KD might cause vascular cellular senescence and vascular endothelial cell damage, and is a potential cause of atherosclerosis in young adults. This study examined the effect of KD and HMG-CoA inhibitors (statins) on vascular cellular senescence and vascular endothelial cells. Candida albicans water-soluble fraction (CAWS) was administered intraperitoneally to 5-week-old male apolipoprotein E-deficient (ApoE-) mice to induce KD-like vasculitis. The mice were then divided into three groups: control, CAWS, and CAWS+statin groups. Ten weeks after injection, the mice were sacrificed and whole aortic tissue specimens were collected. Endothelial nitric oxide synthase (eNOS) expression in the ascending aortic intima epithelium was evaluated using immunostaining. In addition, eNOS expression and levels of cellular senescence markers were measured in RNA and proteins extracted from whole aortic tissue. KD-like vasculitis impaired vascular endothelial cells that produce eNOS, which maintains vascular homeostasis, and promoted macrophage infiltration into the tissue. Statins also restored vascular endothelial cell function by promoting eNOS expression. Statins may be used to prevent secondary cardiovascular events during the chronic phase of KD.

355: RHINOVIRUS-ASSOCIATED ANCA VASCULITIS: A RARE ASSOCIATION

Introduction: The anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitides (AAV) are immune mediated diseases, associated with antigen exposure and host immune response. Approximately 52–80% of patients with AAV have pulmonary abnormalities on chest CT, mainly interstitial lung disease (ILD), granuloma, or alveolar hemorrhage. Myeloperoxidase (MPO) antineutrophil cytoplasmic antibody (ANCA) has been particularly associated with interstitial lung disease and the majority of patients present with pulmonary symptoms prior to the diagnosis of ANCA vasculitis. ILD is a relatively uncommon manifestation of MPO-ANCA, but signifies a poor prognosis. We present a patient with rhinovirus infection associated ANCA vasculitis. Description: A 42-year-old female with a past medical history of COPD, bipolar disorder, and intravenous drug use presented to the emergency department in acute respiratory distress. Computed tomography of the chest revealed bilateral diffuse, patchy ground glass opacities. Respiratory PCR testing was positive for rhinovirus. The patient was admitted to the ICU for acute hypoxic respiratory failure. Her respiratory status continued to decline during the ICU stay. Serum studies including DsDNA, SSA, SSB, anticentromere, myositis, aldolase and ANCA were obtained. The studies were positive for MPO-ANCA. The patient was treated with high dose methylprednisolone. Subsequently, the oxygen demand improved and the patient made a full recovery, with plan for outpatient biopsies. Discussion: MPO-ANCA is a marker which may be induced by various drugs, dust inhalation, smoking, heavy metal exposure, or silica exposure. The hypothesized mechanism involves cytokines produced by antigens to induce MPO expression within the neutrophil cell membrane. The ANCA component binds to MPO to induce neutrophil activation which then activates the inflammatory cascade. The overproduction of cytokines causes vascular endothelial cell damage and ultimately vasculitis. One proposed mechanism of MPO-ANCA involves the alteration in degradation of neutrophil extracellular traps (NETs) likely due to infections. This mechanism leads to an increase in MPO-ANCA binding. NETs have a proliferative effect on lung fibroblasts, and thus are seen alongside fibroblasts in patients with MPO-ANCA interstitial pneumonia.

Ceramide induces pyroptosis through TXNIP/NLRP3/GSDMD pathway in HUVECs

BackgroundPyroptosis of endothelial cells is a new cause of endothelial dysfunction in multiple diseases. Ceramide acts as a potential bioactive mediator of inflammation and increases vascular endothelial permeability in many diseases, whether it can aggravate vascular endothelial injury by inducing cell pyroptosis remains unknown. This study was established to explore the effects of C8-ceramide (C8-Cer) on human umbilical vein vascular endothelial cells (HUVECs) and its possible underlying mechanism.MethodsHUVECs were exposed to various concentrations of C8-Cer for 12 h, 24 h, 48 h. The cell survival rate was measured using the cell counting kit-8 assay. Western blotting and Real-time polymerase chain reaction (RT-PCR) were used to detect the pyroptosis-releated protein and mRNA expressions, respectively. Caspase-1 activity assay was used to detect caspase-1 activity. Hoechst 33342/propidium iodide double staining and flow cytometry were adopted to measure positive staining of cells. Lactate dehydrogenase release assay and enzyme-linked immunosorbent assay were adopted to measure leakage of cellular contents. FITC method was used to detect the permeability of endothelial cells. ROS fluorescence intensity were detected by flow cytometry.ResultsThe viability of HUVECs decreased gradually with the increase in ceramide concentration and time. Ceramide upregulated the expression of thioredoxin interacting protein (TXNIP), NLRP3, GSDMD, GSDMD-NT, caspase-1 and Casp1 p20 at the protein and mRNA level in a dose-dependent manner. It also enhanced the PI uptake in HUVECs and upregulated caspase-1 activity. Moreover, it promoted the release of lactate dehydrogenase, interleukin-1β, and interleukin-18. Meanwhile, we found that ceramide led to increased vascular permeability. The inhibitor of NLRP3 inflammasome assembly, MCC950, was able to disrupt the aforementioned positive loop, thus alleviating vascular endothelial cell damage. Interestingly, inhibition of TXNIP either chemically using verapamil or genetically using small interfering RNA (siRNA) can effectively inhibit ceramide-induced pyroptosis and improved cell permeability. In addition, ceramide stimulated reactive oxygen species (ROS) generation. The pretreatment of antioxidant N-acetylcysteine (NAC), ROS scavenger, blocked the expression of pyroptosis markers induced by C8-cer in HUVECs.ConclusionThe current study demonstrated that C8-Cer could aggravate vascular endothelial cell damage and increased cell permeability by inducing cell pyroptosis. The results documented that the ROS-dependent TXNIP/NLRP3/GSDMD signalling pathway plays an essential role in the ceramide-induced pyroptosis in HUVECs.

Multienzyme-mimic nanogels for reactive oxygen species catalyzing and treatment of H2O2-induced vascular endothelium injury in vitro

Oxidative stress relates to acute and chronic inflammatory diseases. However, antioxidant drugs of available clinically are limited. Design a kind of nanoenzyme with excellent catalytic reactive oxygen species (ROS) property and biocompatibility provides a promising way for the treatment of ROS-related inflammation. The active site components and net environment of nanozymes have an important effect on the nanoenzyme activity. Herein, Er3+ doped metal coordinated polymeric nanogels (SiO2@MPG/Er) nanozymes with anti-oxidative activity of are obtained, which treat vascular endothelial cells damage. The greatly dispersed Ce ion in MPGs is a key active center of mimetic enzyme. Meanwhile, Er3+ ions doping increases oxygen vacancies of samples, which further improve enzyme-like catalytic activity. SiO2@MPG/Er nanoenzyme simultaneously possesses glutathione peroxidase (GPX) and catalase (CAT) enzyme activities, which present catalytic ability of ROS and significantly improve treatment effect in vascular endothelium injury. The SiO2@MPG/Er nanozyme pave a new way to treat cardiovascular diseases related to endothelial damage.

Early ascorbic acid administration prevents vascular endothelial cell damage in septic mice.

Oxidation of BH4, a cofactor of nitric oxide synthase (NOS), produces reactive oxygen species (ROS) through uncoupling of NOS and affects vascular endothelial dysfunction. Ascorbic acid (AsA) inhibits the oxidation of BH4 and reduces ROS. However, the kinetic changes of BH4 in sepsis and its effect on the kinetic changes in AsA administration therapy, as well as the appropriate timing of AsA administration for AsA therapy to be effective, are unclear. Mice with sepsis, induced by cecal ligation and puncture (CLP), were examined for the effect of AsA administration (200 mg/kg) on vascular endothelial cell dysfunction at two administration timings: early group (AsA administered immediately after CLP) and late group (AsA administered 12 h after CLP). Survival rates were compared between the early and late administration groups, and vascular endothelial cell damage, indicated by the dihydrobiopterin/tetrahydrobiopterin ratio, serum syndecan-1, and endothelial nitric oxide synthase, as well as liver damage, were examined. The early group showed significantly improved survival compared to the non-treatment group (p < 0.05), while the late group showed no improved survival compared to the non-treatment group. Compared to the non-treated group, the early AsA group showed less oxidation of BH4 in sepsis. Syndecan1, a marker of vascular endothelial cell damage, was less elevated and organ damage was reduced in the early AsA-treated group. In septic mice, early AsA administration immediately after CLP may protect vascular endothelial cells by inhibiting BH4 oxidation, thereby reducing organ dysfunction and improving survival.

Environmental factors influencing the risk of ANCA-associated vasculitis.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of diseases characterized by inflammation and destruction of small and medium-sized blood vessels. Clinical disease phenotypes include microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic granulomatosis with polyangiitis (EGPA). The incidence of AAV has been on the rise in recent years with advances in ANCA testing. The etiology and pathogenesis of AAV are multifactorial and influenced by both genetic and environmental factors, as well as innate and adaptive immune system responses. Multiple case reports have shown that sustained exposure to silica in an occupational environment resulted in a significantly increased risk of ANCA positivity. A meta-analysis involving six case-control studies showed that silica exposure was positively associated with AAV incidence. Additionally, exposure to air pollutants, such as carbon monoxide (CO), is a risk factor for AAV. AAV has seasonal trends. Studies have shown that various environmental factors stimulate the body to activate neutrophils and expose their own antigens, resulting in the release of proteases and neutrophil extracellular traps, which damage vascular endothelial cells. Additionally, the activation of complement replacement pathways may exacerbate vascular inflammation. However, the role of environmental factors in the etiology of AAV remains unclear and has received little attention. In this review, we summarized the recent literature on the study of environmental factors, such as seasons, air pollution, latitude, silica, and microbial infection, in AAV with the aim of exploring the relationship between environmental factors and AAV and possible mechanisms of action to provide a scientific basis for the prevention and treatment of AAV.

An Update Review of the Pathogenesis Hypothesis in Preeclampsia

Objectives: Hypertensive disorders occur in approximately 12% to 22% of pregnancies and cause substantial perinatal morbidity and mortality of both mother and fetus. Hypertensive disease is directly responsible for approximately 20% of maternal deaths and can be classified as chronic hypertension, gestational hypertension, preeclampsia-eclampsia, and chronic hypertension with superimposed preeclampsia. At present, the pathogenesis of preeclampsia is still unclear, we wrote this article to make a uptodate review of this disease. Mechanism: A comprehensive search of several databases was conducted from inception up to March 2022. The searched databases were Web of Science, MEDLINE,Ovid, and Cochrane Database of Systematic Reviews. The search strategy included the combinations of the following medical terms: Hypertensive disorders; preeclampsia; mechanism; pathogenesis hypothesis. Findings in Brief: At present,the pathogenesis of preeclampsia is still unclear, the theory of Genetic,Inflammatory Response, Immune Imbalance in Maternal-Fetal Interface, Oxidative Stress, Vascular Endothelial Cell Damage are supposed involved in the progress of preeclampsia. Conclusions: Although there are various theories mentioned above, none of the hypothesis can fully explain preeclampsia. More research is needed on the mechanism of preeclampsia.

Limiting Immunogenicity of Diabetic Retinopathy Patient-Derived Induced Pluripotent Stem Cells by Knocking out Human Leukocyte Antigen and Overexpressing Cluster of Differentiation 47

Introduction: Diabetic retinopathy (DR), the most common complication of diabetes, is characterized by vision loss due to vascular endothelial cell damage of the retina. Notably, induced pluripotent stem cell (iPSC) therapy has shown promise in the regeneration of the retina after damage. A limitation of using these cells includes the risk of immune-rejection. The knockout of human leukocyte antigen (HLA) proteins prevents a host immune response to non-native cells; however, HLA depletion introduces natural killer (NK) cell-mediated responses. Overexpression of cluster of differentiation 47 (CD47) inhibits the activity of NK cells. This project aims to create a universal DR patient-derived iPSC platform whose immunogenicity is limited through genetic alterations. Methods: iPSCs will be reprogrammed from DR patient-derived fibroblasts and CRISPR-Cas9 will be used to knock out HLA and overexpress CD47. Alterations will be validated through Sanger sequencing, Western Blot and Immunofluorescence (IF) analysis. DR patient-derived iPSCs will be differentiated into endothelial cells to mimic the DR afflicted endothelial cells. These differentiated cells will then be co-cultured with NK cells and a cytotoxicity assay will be performed. Specifically, a chromium-release assay will be used by loading radioactive chromium into the genetically modified and unmodified endothelial cells and the chromium released by dying cells was monitored. Results: Compared to the unmodified cells, we expect less NK-mediated cell death for the genetically altered endothelial cells. Discussion: Effectively limiting the immunogenicity of the donor-derived iPSCs can establish a universal platform for future studies in DR therapy. Conclusion: The resulting donor-derived iPSCs can be used to test drug therapies for DR or new methods to repair blood vessel damage, among a multitude of new research.

The Role of Heparin in COVID-19: An Update after Two Years of Pandemics.

Coronavirus disease 2019 (COVID-19) is associated with an increased risk of venous thromboembolism (VTE) and coagulopathy, especially in critically ill patients. Endothelial damage induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is emerging as a crucial pathogenetic mechanism for the development of complications in an acute phase of the illness and for several postdischarge sequalae. Heparin has been shown to have a positive impact on COVID-19 due to its anticoagulant function. Moreover, several other biological actions of heparin were postulated: a potential anti-inflammatory and antiviral effect through the main protease (Mpro) and heparansulfate (HS) binding and a protection from the damage of vascular endothelial cells. In this paper, we reviewed available evidence on heparin treatment in COVID-19 acute illness and chronic sequalae, focusing on the difference between prophylactic and therapeutic dosage.

Inspiration from the research advances in microcirculatory dysfunction to the treatment of burn shock and burn septic shock

Microcirculatory dysfunction is an important pathophysiological change of shock. In the last decade, many researches on the mechanism of microcirculatory dysfunction have been involved in areas such as the glycocalyx damage of vascular endothelial cells, macrocirculation- microcirculation discoupling, vascular hyporeactivity, and microcirculation monitoring. Accordingly, this paper discussed how these research findings can be applied to burn patients, with the aim of alerting the clinicians to improving microcirculation, and maintaining hemodynamic coordination during the treatment of burn shock and burn septic shock. In addition, with the development of accurate and reliable microcirculation monitoring techniques, it is necessary to carry out multi-center clinical trials to reveal the clinical significance of target-oriented shock resuscitation protocol combining macrocirculatory and microcirculatory parameters.

Melatonin alleviates vascular endothelial cell damage by regulating an autophagy-apoptosis axis in Kawasaki disease.

ObjectivesMelatonin has been reported to be an appropriate candidate for mitigating various cardiovascular injuries, owing to its versatility. This study aimed to explore the role of melatonin in Kawasaki disease (KD)‐associated vasculitis and its underlying mechanisms.Material and MethodsThe role of melatonin was evaluated in human coronary artery endothelial cells (HCAECs), peripheral blood mononuclear cells from KD patients, human THP1 cell line in vitro, and a Candida albicans water‐soluble fraction (CAWS)‐induced KD mouse model in vivo. Cell proliferation assay, cell apoptosis assay, cell co‐culture, RNA extraction, RNA sequencing, reverse transcription quantitative PCR, enzyme‐linked immunosorbent assay (ELISA), transwell assay, western blot, dual‐luciferase reporter assay, and autophagic flux assay were performed to investigate the function and regulatory mechanisms of melatonin in vitro, while haematoxylin and eosin staining, Verhoeff's van Gieson staining, ELISA, and immunohistochemical analysis were performed to detect the effect of melatonin in vivo.ResultsMelatonin suppressed cell apoptosis directly reduced the expression of endothelial cell damage markers in HCAECs, and alleviated vasculitis in the CAWS‐induced KD mouse model. Mechanistically, melatonin promoted autophagy by activating the melatonin/ melatonin receptor (MT)/cAMP‐response element binding protein (CREB) pathway and upregulating the expression of autophagy‐related gene‐3, thereby suppressing cell apoptosis in an autophagy‐dependent manner. Additionally, melatonin decreased the production of pro‐inflammatory cytokines in macrophages and indirectly reduced the immunopathological damage of HCAECs.ConclusionsThis study revealed that melatonin protects vascular endothelial cells in KD, by suppressing cell apoptosis in an autophagy‐dependent manner and reducing the immunopathological damage mediated by macrophages.

Coagulopathy and Traumatic Brain Injury: Overview of New Diagnostic and Therapeutic Strategies.

Coagulopathy is a common sequela of traumatic brain injury. Consumptive coagulopathy and secondary hyperfibrinolysis are associated with hypercoagulability. In addition, fibrinolytic pathways are hyperactivated as a result of vascular endothelial cell damage in the injured brain. Coagulation and fibrinolytic parameters change dynamically to reflect these pathologies. Fibrinogen is consumed and degraded after injury, with fibrinogen concentrations at their lowest 3-6 h after injury. Hypercoagulability causes increased fibrinolytic activity, and plasma levels of D-dimer increase immediately after traumatic brain injury, reaching a maximum at 3 h. Owing to disseminated intravascular coagulation in the presence of fibrinolysis, the bleeding tendency is highest within the first 3 h after injury, and often a condition called “talk and deteriorate” occurs. In neurointensive care, it is necessary to measure coagulation and fibrinolytic parameters such as fibrinogen and D-dimer routinely to predict and prevent the development of coagulopathy and its negative outcomes. Currently, the only evidence-based treatment for traumatic brain injury with coagulopathy is tranexamic acid in the subset of patients with mild-to-moderate traumatic brain injury. Coagulation and fibrinolytic parameters should be closely monitored, and treatment should be considered on a patient-by-patient basis.

Effect and mechanism of TFEB on pyroptosis in HK-2 cells induced by high glucose

As a newly discovered way of cell death, pyroptosis has been gradually discovered in acute and chronic kidney disease. Existing studies have shown that reactive oxygen species (ROS) can induce pyroptosis and release a large number of inflammatory mediators, resulting in kidney damage. As a transcription factor, transcription factor EB(TFEB) can regulate mitochondrial energy metabolism, reduce the production of ROS, and reduce the inflammatory damage of vascular endothelial cells. In a high-glucose environment, whether TFEB can regulate oxidative stress in HK-2 cells, thereby reducing pyroptosis, has not yet been studied. This study found that in HK-2 cells, with the prolongation of high concentration glucose stimulation, the expression level of TFEB showed a trend of first increasing and then decreasing; and nuclear translocation of TFEB expression occurred within 24 h. In high-glucose environment, the expression of pyroptosis-related proteins gradually increased over time, while the expression of anti-oxidative stress proteins superoxide dismutase2(SOD2)and NAD(P)H: quinone oxidoreductase 1(NQO1) showed a trend of first increasing and then decreasing. After TFEB was transfected with overexpression plasmid, the expression levels of SOD2 and NQO1 increased significantly, and the expression of pyroptosis-related proteins decreased. Observed under a confocal microscope after Mitosox red staining, the expression of ROS in the TFEB overexpression group decreased. After down-regulating the expression of TFEB, the expression of ROS increased. The research results suggested that in HK-2 cells in the high glucose environment, TFEB may affect the pyroptosis by regulating the expression of antioxidant enzymes SOD2 and NQO1, which provides a new therapeutic idea for the treatment of diabetic nephropathy.

Persistent Lung Injury and Prothrombotic State in Long COVID.

Lung injury may persist during the recovery period of COVID-19 as shown through imaging, six-minute walk, and lung function tests. The pathophysiological mechanisms leading to long COVID have not been adequately explained. Our aim is to investigate the basis of pulmonary susceptibility during sequelae and the possibility that prothrombotic states may influence long-term pulmonary symptoms of COVID-19. The patient’s lungs remain vulnerable during the recovery stage due to persistent shedding of the virus, the inflammatory environment, the prothrombotic state, and injury and subsequent repair of the blood-air barrier. The transformation of inflammation to proliferation and fibrosis, hypoxia-involved vascular remodeling, vascular endothelial cell damage, phosphatidylserine-involved hypercoagulability, and continuous changes in serological markers all contribute to post-discharge lung injury. Considering the important role of microthrombus and arteriovenous thrombus in the process of pulmonary functional lesions to organic lesions, we further study the possibility that prothrombotic states, including pulmonary vascular endothelial cell activation and hypercoagulability, may affect long-term pulmonary symptoms in long COVID. Early use of combined anticoagulant and antiplatelet therapy is a promising approach to reduce the incidence of pulmonary sequelae. Essentially, early treatment can block the occurrence of thrombotic events. Because impeded pulmonary circulation causes large pressure imbalances over the alveolar membrane leading to the infiltration of plasma into the alveolar cavity, inhibition of thrombotic events can prevent pulmonary hypertension, formation of lung hyaline membranes, and lung consolidation.

Hypoxanthine Reduces Radiation Damage in Vascular Endothelial Cells and Mouse Skin by Enhancing ATP Production via the Salvage Pathway

An effective method that can protect radiation-damaged tissues from apoptosis and promote tissue repair has not been reported to date. Hypoxanthine (Hx) is an intermediate metabolite in the purine degradation system that serves as a substrate for ATP synthesis via the salvage pathway. In this study, we focused on the transient decrease in intracellular ATP concentration after radiation exposure and examined the protective effect of Hx against radiation-induced tissue damage. Human umbilical vein endothelial cells were X irradiated, and the cell viability and incidence of apoptosis and DNA double-strand breaks (DSBs) were evaluated at different Hx concentrations. We found that in the presence of 2-100 µM Hx, the percentages of DSBs and apoptotic cells after 2, 6 and 10 Gy dose of radiation significantly decreased, whereas cell viability increased in a concentration-dependent manner. Moreover, the addition of Hx increased the levels of AMP, ADP, and ATP in the cells at 2 h postirradiation, suggesting that Hx was used for adenine nucleotide synthesis through the salvage pathway. Administration of a xanthine oxidoreductase inhibitor to a mouse model of radiation dermatitis resulted in increased blood Hx levels that inhibited severe dermatitis and accelerated recovery. In conclusion, the findings provide evidence that increasing the levels of Hx to replenish ATP could be an effective strategy to reduce radiation-induced tissue damage and elucidating the detailed mechanisms underlying the protective effects of Hx could help develop new protective strategies against radiation.