Pro-inflammation and pro-atherosclerotic responses to short-term air pollution exposure associated with alterations in sphingolipid ceramides and neutrophil extracellular traps.

Air pollution has been associated with the development of atherosclerosis; however, the pathophysiological mechanisms underlying pro-atherosclerotic effects of air pollution exposure remain unclear. We conducted a prospective panel study in Beijing and recruited 152 participants with four monthly visits from September 2019 to January 2020. Linear mixed-effect models were applied to estimate the associations linking short-term air pollution exposure to biomarkers relevant to ceramide metabolism, pro-inflammation (neutrophil extracellular traps formation and systemic inflammation) and pro-atherosclerotic responses (endothelial stimulation, plaque instability, coagulation activation, and elevated blood pressure). We further explored whether ceramides and inflammatory indicators could mediate the alterations in the profiles of pro-atherosclerotic responses. We found that significant increases in levels of circulating ceramides of 9.7% (95% CIs: 0.7, 19.5) to 96.9% (95% CIs: 23.1, 214.9) were associated with interquartile range increases in moving averages of ambient air pollutant metrics, including fine particulate matter (PM2.5), black carbon, particles in size fractions of 100-560 nm, nitrogen dioxide, carbon monoxide and sulfur dioxide at prior up to 7 days. Higher air pollution levels were also associated with activated neutrophils (increases in citrullinated histone H3, neutrophil elastase, double-stranded DNA, and myeloperoxidase) and exacerbation of pro-atherosclerotic responses (e.g., increases in vascular endothelial growth factor, lipoprotein-associated phospholipase A2, matrix metalloproteinase-8, P-selectin, and blood pressure). Mediation analyses further showed that dysregulated ceramide metabolism and potentiated inflammation could mediate PM2.5-associated pro-atherosclerotic responses. Our findings extend the understanding on potential mechanisms of air pollution-associated atherosclerosis, and suggest the significance of reducing air pollution as priority in urban environments.

The markers and risk stratification model of intracranial aneurysm instability in a large Chinese cohort.

Intracranial aneurysm is the leading cause of nontraumatic subarachnoid hemorrhage. Evaluating the unstable (rupture and growth) risk of aneurysms is helpful to guild decision-making for unruptured intracranial aneurysms (UIA). This study aimed to develop a model for risk stratification of UIA instability. The UIA patients from two prospective, longitudinal multicenter Chinese cohorts recruited from January 2017 to January 2022 were set as the derivation cohort and validation cohort. The primary endpoint was UIA instability, comprising aneurysm rupture, growth, or morphology change, during a 2-year follow-up. Intracranial aneurysm samples and corresponding serums from 20 patients were also collected. Metabolomics and cytokine profiling analysis were performed on the derivation cohort (758 single-UIA patients harboring 676 stable UIAs and 82 unstable UIAs). Oleic acid (OA), arachidonic acid (AA), interleukin 1ß (IL-1ß), and tumor necrosis factor-α (TNF-α) were significantly dysregulated between stable and unstable UIAs. OA and AA exhibited the same dysregulated trends in serums and aneurysm tissues. The feature selection process demonstrated size ratio, irregular shape, OA, AA, IL-1ß, and TNF-α as features of UIA instability. A machine-learning stratification model (instability classifier) was constructed based on radiological features and biomarkers, with high accuracy to evaluate UIA instability risk (area under curve (AUC), 0.94). Within the validation cohort (492 single-UIA patients harboring 414 stable UIAs and 78 unstable UIAs), the instability classifier performed well to evaluate the risk of UIA instability (AUC, 0.89). Supplementation of OA and pharmacological inhibition of IL-1ß and TNF-α could prevent intracranial aneurysms from rupturing in rat models. This study revealed the markers of UIA instability and provided a risk stratification model, which may guide treatment decision-making for UIAs.

Angiogenesis in hepatocellular carcinoma: mechanisms and anti-angiogenic therapies.

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-associated death worldwide. Angiogenesis, the process of formation of new blood vessels, is required for cancer cells to obtain nutrients and oxygen. HCC is a typical hypervascular solid tumor with an aberrant vascular network and angiogenesis that contribute to its growth, progression, invasion, and metastasis. Current anti-angiogenic therapies target mainly tyrosine kinases, vascular endothelial growth factor receptor (VEGFR), and platelet-derived growth factor receptor (PDGFR), and are considered effective strategies for HCC, particularly advanced HCC. However, because the survival benefits conferred by these anti-angiogenic therapies are modest, new anti-angiogenic targets must be identified. Several recent studies have determined the underlying molecular mechanisms, including pro-angiogenic factors secreted by HCC cells, the tumor microenvironment, and cancer stem cells. In this review, we summarize the roles of pro-angiogenic factors; the involvement of endothelial cells, hepatic stellate cells, tumor-associated macrophages, and tumor-associated neutrophils present in the tumor microenvironment; and the regulatory influence of cancer stem cells on angiogenesis in HCC. Furthermore, we discuss some of the clinically approved anti-angiogenic therapies and potential novel therapeutic targets for angiogenesis in HCC. A better understanding of the mechanisms underlying angiogenesis may lead to the development of more optimized anti-angiogenic treatment modalities for HCC.

Gasdermin D Deficiency in Vascular Smooth Muscle Cells Ameliorates Abdominal Aortic Aneurysm Through Reducing Putrescine Synthesis.

Abdominal aortic aneurysm (AAA) is a common vascular disease associated with significant phenotypic alterations in vascular smooth muscle cells (VSMCs). Gasdermin D (GSDMD) is a pore-forming effector of pyroptosis. In this study, the role of VSMC-specific GSDMD in the phenotypic alteration of VSMCs and AAA formation is determined. Single-cell transcriptome analyses reveal Gsdmd upregulation in aortic VSMCs in angiotensin (Ang) II-induced AAA. VSMC-specific Gsdmd deletion ameliorates Ang II-induced AAA in apolipoprotein E (ApoE)-/- mice. Using untargeted metabolomic analysis, it is found that putrescine is significantly reduced in the plasma and aortic tissues of VSMC-specific GSDMD deficient mice. High putrescine levels trigger a pro-inflammatory phenotype in VSMCs and increase susceptibility to Ang II-induced AAA formation in mice. In a population-based study, a high level of putrescine in plasma is associated with the risk of AAA (p < 2.2 × 10-16 ), consistent with the animal data. Mechanistically, GSDMD enhances endoplasmic reticulum stress-C/EBP homologous protein (CHOP) signaling, which in turn promotes the expression of ornithine decarboxylase 1 (ODC1), the enzyme responsible for increased putrescine levels. Treatment with the ODC1 inhibitor, difluoromethylornithine, reduces AAA formation in Ang II-infused ApoE-/- mice. The findings suggest that putrescine is a potential biomarker and target for AAA treatment.

In vivo imaging of heart failure with preserved ejection fraction by simultaneous monitoring of cardiac nitric oxide and glutathione using a three-channel fluorescent probe.

The pathophysiology of heart failure with preserved ejection fraction (HFpEF) remains unclear, making the diagnosis and treatment challenging. Cardiac oxidative and nitrative stress are strongly implicated in the pathogenesis of HFpEF. Herein, we present a unique three-channel fluorescent probe for evaluating cardiac oxidative and nitrative stress in HFpEF by simultaneous detection of NO and GSH. The probe exhibits a native green fluorescence (probe channel), while the presence of GSH and NO can sensitively turn the native green fluorescence into red fluorescence (GSH channel) and near-infrared fluorescence (NO channel), respectively. The probe clearly reveals that both GSH and NO levels are upregulated in cardiomyocytes and heart tissue with HFpEF. Moreover, it uncovers that the enhancement in NO and GSH levels are closely associated with increased level of iNOS (inducible nitric oxide synthase) and activation of the Keap1 (Kelch-like ECH-associated protein 1)/Nrf2 (nuclear factor erythroid 2-related factor 2)/ARE (antioxidant response element) signaling pathway in cardiomyocytes, respectively. This work proposes a promising approach for distinguishing normal heart and HFpEF heart by in vivo noninvasive imaging of both GSH and NO, and greatly contributing to the improvement of the diagnosis and treatment of HFpEF.

Integrating Choline and Specific Intestinal Microbiota to Classify Type 2 Diabetes in Adults: A Machine Learning Based Metagenomics Study.

Emerging evidence is examining the precise role of intestinal microbiota in the pathogenesis of type 2 diabetes. The aim of this study was to investigate the association of intestinal microbiota and microbiota-generated metabolites with glucose metabolism systematically in a large cross-sectional study in China. 1160 subjects were divided into three groups based on their glucose level: normal glucose group (n=504), prediabetes group (n=394), and diabetes group (n=262). Plasma concentrations of TMAO, choline, betaine, and carnitine were measured. Intestinal microbiota was measured in a subgroup of 161 controls, 144 prediabetes and 56 diabetes by using metagenomics sequencing. We identified that plasma choline [Per SD of log-transformed change: odds ratio 1.36 (95 confidence interval 1.16, 1.58)] was positively, while betaine [0.77 (0.66, 0.89)] was negatively associated with diabetes, independently of TMAO. Individuals with diabetes could be accurately distinguished from controls by integrating data on choline, and certain microbiota species, as well as traditional risk factors (AUC=0.971). KOs associated with the carbohydrate metabolism pathway were enhanced in individuals with high choline level. The functional shift in the carbohydrate metabolism pathway in high choline group was driven by species Ruminococcus lactaris, Coprococcus catus and Prevotella copri. We demonstrated the potential ability for classifying diabetic population by choline and specific species, and provided a novel insight of choline metabolism linking the microbiota to impaired glucose metabolism and diabetes.

Effect of Lipoprotein(a) on Stroke Recurrence Attenuates at Low LDL-C (Low-Density Lipoprotein) and Inflammation Levels.

BACKGROUND: Lp(a) (lipoprotein(a)) contributes to cardiovascular disease mainly through proatherogenic and proinflammatory effects. Here, we aimed to evaluate whether a residual stroke risk of Lp(a) would remain when the LDL-C (low-density lipoprotein cholesterol) and inflammatory levels are maintained low. METHODS: This prospective cohort study included 9899 patients with ischemic stroke or transient ischemic attack from the Third China National Stroke Registry who had measurements of plasma Lp(a) and were followed up for 1 year. Cutoffs were set at the 50 mg/dL for Lp(a). LDL-C was corrected for Lp(a)-derived cholesterol (LDL-Cc [LDL-C corrected]) and cutoffs were set at 55 and 70 mg/dL.The threshold values of IL-6 (interleukin 6) and hsCRP (high-sensitive C-reactive protein) were the median 2.65 ng/L and 2 mg/L. Multivariable-adjusted hazard ratio (HR) were calculated using Cox regression models for each category to investigate the associations of Lp(a) with stroke recurrence within 1 year. RESULTS: Among all patients, those with Lp(a) ≥50 mg/dL were at higher stroke recurrence risk than those with Lp(a) <50 mg/dL (11.5% versus 9.4%; adjusted HR, 1.20 [95% CI, 1.02-1.42]). However, the risk associated with elevated Lp(a) was attenuated in patients with LDL-Cc <55 mg/dL (high Lp(a) versus low Lp(a): 8.9% versus 9.0%; adjusted HR, 0.92 [95% CI, 0.65-1.30]) or IL-6 <2.65 ng/L (9.0% versus 7.8%; adjusted HR, 1.14 [95% CI, 0.87-1.49]). Notably, in the group with both low LDL-Cc and inflammation levels, the rate of patients with high Lp(a) did not significantly different from the rate of patients with low Lp(a; LDL-Cc <55 mg/dL and IL-6 <2.65 ng/L: 6.2% versus 7.1%; adjusted HR, 0.86 [95% CI, 0.46-1.62]; LDL-Cc <55 mg/dL and hsCRP <2 mg/L: 7.7% versus 7.6%; adjusted HR, 0.97 [95% CI, 0.57-1.66]). However, there was no interaction between the LDL-Cc, IL-6, hsCRP, and Lp(a) levels on stroke recurrence risk. CONCLUSIONS: Increased Lp(a) was significantly associated with stroke recurrence risk in patients with ischemic stroke/transient ischemic attack. However, at low LDL-Cc or IL-6 levels, the elevated Lp(a) -associated stroke recurrence risk was attenuated in a secondary prevention setting.

Untargeted metabolomics identifies succinate as a biomarker and therapeutic target in aortic aneurysm and dissection.

AIMS: Aortic aneurysm and dissection (AAD) are high-risk cardiovascular diseases with no effective cure. Macrophages play an important role in the development of AAD. As succinate triggers inflammatory changes in macrophages, we investigated the significance of succinate in the pathogenesis of AAD and its clinical relevance. METHODS AND RESULTS: We used untargeted metabolomics and mass spectrometry to determine plasma succinate concentrations in 40 and 1665 individuals of the discovery and validation cohorts, respectively. Three different murine AAD models were used to determine the role of succinate in AAD development. We further examined the role of oxoglutarate dehydrogenase (OGDH) and its transcription factor cyclic adenosine monophosphate-responsive element-binding protein 1 (CREB) in the context of macrophage-mediated inflammation and established p38αMKOApoe-/- mice. Succinate was the most upregulated metabolite in the discovery cohort; this was confirmed in the validation cohort. Plasma succinate concentrations were higher in patients with AAD compared with those in healthy controls, patients with acute myocardial infarction (AMI), and patients with pulmonary embolism (PE). Moreover, succinate administration aggravated angiotensin II-induced AAD and vascular inflammation in mice. In contrast, knockdown of OGDH reduced the expression of inflammatory factors in macrophages. The conditional deletion of p38α decreased CREB phosphorylation, OGDH expression, and succinate concentrations. Conditional deletion of p38α in macrophages reduced angiotensin II-induced AAD. CONCLUSION: Plasma succinate concentrations allow to distinguish patients with AAD from both healthy controls and patients with AMI or PE. Succinate concentrations are regulated by the p38α-CREB-OGDH axis in macrophages.

ICAM-1 Activates Platelets and Promotes Endothelial Permeability through VE-Cadherin after Insufficient Radiofrequency Ablation.

Radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC) often leads to aggressive local recurrence and increased metastasis, and vascular integrity and platelets are implicated in tumor metastasis. However, whether interactions between endothelial cells and platelets induce endothelial permeability in HCC after insufficient RFA remains unclear. Here, significantly increased CD62P-positive platelets and sP-selectin in plasma are observed in HCC patients after RFA, and tumor-associated endothelial cells (TAECs) activate platelets and are susceptible to permeability after heat treatment in the presence of platelets in vitro. In addition, tumors exhibit enhanced vascular permeability after insufficient RFA in mice; heat treatment promotes platelets-induced endothelial permeability through vascular endothelial (VE)-cadherin, and ICAM-1 upregulation in TAECs after heat treatment results in platelet activation and increased endothelial permeability in vitro. Moreover, the binding interaction between upregulated ICAM-1 and Ezrin downregulates VE-cadherin expression. Furthermore, platelet depletion or ICAM-1 inhibition suppresses tumor growth and metastasis after insufficient RFA in an orthotopic tumor mouse model, and vascular permeability decreases in ICAM-1-/- mouse tumor after insufficient RFA. The findings suggest that ICAM-1 activates platelets and promotes endothelial permeability in TAECs through VE-cadherin after insufficient RFA, and anti-platelet and anti-ICAM-1 therapy can be used to prevent progression of HCC after insufficient RFA.

p38α in macrophages aggravates arterial endothelium injury by releasing IL-6 through phosphorylating megakaryocytic leukemia 1.

BACKGROUND: Macrophages regulate the inflammatory response and affect re-endothelialization. Inflammation and macrophages play important roles in promoting tissue repair, but p38α mitogen-activated protein kinase's role in re-endothelialization is unknown. METHODS AND RESULTS: Wire injuries of carotid arteries and Evans blue staining were performed in macrophage-specific p38α-knockout (p38αfl/flLysMCre+/-) mice and control mice (p38αfl/fl). Re-endothelialization of the carotid arteries at 3, 5 and 7 days was significantly promoted in p38αfl/flLysMCre+/- mice. In vitro experiments indicated that both the proliferation and migration of endothelial cells were enhanced in conditioned medium from peritoneal macrophages of p38αfl/flLysMCre+/- mice. Interleukin-6 (IL-6) level was decreased significantly in macrophages of p38αfl/flLysMCre+/- mice and an IL-6-neutralizing antibody promoted endothelial cell migration in vitro and re-endothelialization in p38αfl/fl mice in vivo. Phosphoproteomics revealed that the phosphorylation level of S544/T545/S549 sites in megakaryocytic leukemia 1 (MKL1) was decreased in p38αfl/flLysMCre+/- mice. The mutation of either S544/S549 or T545/S549 sites could reduce the expression of IL-6 and the inhibition of MKL1 reduced the expression of IL-6 in vitro and promoted re-endothelialization in vivo. CONCLUSION: p38α in macrophages aggravates injury of arteries by phosphorylating MKL1, and increasing IL-6 expression after vascular injury.

Changes in the concentrations of trimethylamine N-oxide (TMAO) and its precursors in patients with amyotrophic lateral sclerosis.

To compare the plasma concentrations of trimethylamine N-oxide (TMAO) and its precursors in amyotrophic lateral sclerosis (ALS) patients, their spouses and healthy controls and to find associations between gut microbiota metabolites and ALS. ALS patients were recruited at Peking University Third Hospital from January 2015 to December 2018. Information was collected from their spouses at the same time. Age and gender matched healthy controls were recruited from individuals who visited the physical examination center for health checkups. Blood samples were collected after at least 4 h of fasting. Concentrations of the metabolites were quantified using stable isotope dilution liquid chromatography-tandem mass spectrometry. Group differences were analyzed using parametric and nonparametric tests, as appropriate. In this study, 160 patients with ALS were recruited. In these patients, 63 were compared with their spouses, 148 were compared with age and gender matched controls, and 60 were compared with both their spouses and heathy controls in the same time. The carnitine concentration was significantly higher in patients than in their spouses, while there were no significant differences in the concentrations of other metabolites. The carnitine and betaine concentrations were higher, while the choline, TMAO and butyrobetaine concentrations were lower in ALS than in healthy controls. The concentrations of the metabolites in the spouses were more similar to the ALS patients rather than to the healthy controls. In the ALS group, the plasma concentrations of carnitine, betaine, choline and TMAO were inversely related to the severity of upper motor neuron impairment. The TMAO metabolic pathway of the gut microbiota is disturbed in both ALS patients and their spouses, which might suggest that the changes in the gut microbiota occurred before disease onset. The negative correlations between the involvement of UMNs and the concentrations of the metabolites might suggest that the inhibition of this metabolic pathway might lead to a better prognosis in ALS patients.

ATPase Inhibitory Factor 1 Promotes Hepatocellular Carcinoma Progression After Insufficient Radiofrequency Ablation, and Attenuates Cell Sensitivity to Sorafenib Therapy.

Epithelial-mesenchymal transition (EMT) and angiogenesis is involved in tumor progression after radiofrequency ablation (RFA). ATPase inhibitory factor 1 (IF1) is a bad predictor of prognosis. Sorafenib inhibited EMT of hepatocellular carcinoma (HCC) after RFA. Whether IF1 promotes the EMT and angiogenesis of HCC and attenuates the effect of sorafenib after insufficient RFA is investigated. In this study, higher expression of IF1 was found in residual tumor after insufficient RFA. Hep3B or Huh7 cells after insufficient RFA were designated as Hep3B-H or Huh7-H cells in vitro. Hep3B-H or Huh7-H cells exhibited enhanced capacities of colony formation, migration, and increased expression of EMT associated markers and IF1 compared with Hep3B or Huh7 cells. IF1 knockdown in Hep3B-H or Huh7-H cells decreased the colony formation and migratory capacity, and IF1 overexpression in Hep3B or Huh7 cells increased these capacities. IF1 in HCC cells directly and indirectly affected angiogenesis of TAECs after insufficient RFA. IF1 promoted HCC cells growth and metastasis after insufficient RFA. IF1 increased HCC cells resistance after insufficient RFA to sorafenib. Higher IF1 expression indicated poor disease survival in HCC patients after sorafenib therapy. NF-κB activation induced by IF1 attenuated the effect of sorafenib on HCC cells after insufficient RFA. Our results demonstrated that IF1 promotes the EMT and angiogenesis, and attenuates HCC cell sensitivity to sorafenib after insufficient RFA through NF-κB signal pathway.

Elevated lipid levels in patients with achilles tendon ruptures: a retrospective matching study.

BACKGROUND: Achilles tendon rupture (ATR) can lead to significant disability of patients. However, whether serum lipid levels are associated with ATR is still unclear. This study aimed to examine the difference in lipid levels between patients with and those without ATR. METHODS: Patients who received ATR surgery during January 2017 to December 2017 were categorized into the case group, and those who had physical examinations during the same period without ATR were in the control group. Different matching methods [case-control matching (CCM) and propensity score matching (PSM)] were used to match the cases and controls at a 1:1 ratio. RESULTS: Among a total of 216 pairs of subjects with CCM, cholesterol, triglyceride, and low-density lipoprotein (LDL) levels were significantly higher (all P<0.05) in the case group than in the control group. Among 241 pairs of subjects with PSM, the same results as those with CCM were obtained. Abnormal rates of cholesterol, triglyceride, and LDL levels in the case group were also significantly higher than those in the control group in CCM and PSM (all P<0.05). After adjusting for the factors of height and weight, there were still significant differences in cholesterol, triglyceride, and LDL levels, as well as high-density lipoprotein levels, between the case and control groups (all P<0.05). CONCLUSIONS: Cholesterol, triglyceride, and LDL levels in patients with ATR are higher than those in healthy people. Further studies are required to verify the effect of some components of lipids on Achilles tendon structure.

HuR regulates phospholamban expression in isoproterenol-induced cardiac remodelling.

AIMS: The elevated expression of phospholamban (PLB) has been observed in heart failure and cardiac remodelling, inhibiting the affinity of Ca2+ pump to Ca2+ thereby impairing heart relaxation. However, the mechanisms underlying the regulation of PLB remains to be further studied. The present study aims to test the role of RNA-binding protein HuR in the regulation of PLB and the impact of this regulatory process in cardiac remodelling. METHODS AND RESULTS: A mouse model specifically deleted HuR in cardiomyocytes were used for testing the role of HuR in regulating PLB during isoproterenol (ISO)-induced cardiac remodelling. HuR deficiency did not significantly influence the phenotype and function of mouse heart under static status. However, deletion of HuR in cardiomyocytes mitigated the effect of ISO in inducing PLB expression and reducing ß1-AR expression, in turn aggravating ISO-induced myocardial hypertrophy and cardiac fibrosis. In H9C2 cells, association of HuR with PLB and ß1-AR mRNAs stabilized PLB mRNA and destabilized ß1-AR mRNA, respectively. CONCLUSION: HuR stabilizes PLB mRNA and destabilizes ß1-AR mRNA. The HuR-PLB and HuR-ß1-AR regulatory processes impact on ISO-induced cardiac remodelling.

Endogenous cholesterol ester hydroperoxides modulate cholesterol levels and inhibit cholesterol uptake in hepatocytes and macrophages.

Dysregulation of cholesterol metabolism represents one of the major risk factors for atherosclerotic cardiovascular disease (CVD). Oxidized cholesterol esters (oxCE) in low-density lipoprotein (LDL) have been implicated in CVD but the underlying mechanisms remain poorly defined. We use a targeted lipidomic approach to demonstrate that levels of oxCEs in human plasma are associated with different types of CVD and significantly elevated in patients with myocardial infarction. We synthesized a major endogenous cholesterol ester hydroperoxide (CEOOH), cholesteryl-13(cis, trans)-hydroperoxy-octadecadienoate (ch-13(c,t)-HpODE) and show that this endogenous compound significantly increases plasma cholesterol level in mice while decrease cholesterol levels in mouse liver and peritoneal macrophages, which is primarily due to the inhibition of cholesterol uptake in macrophages and liver. Further studies indicate that inhibition of cholesterol uptake by ch-13(c,t)-HpODE in macrophages is dependent on LXRα-IDOL-LDLR pathway, whereas inhibition on cholesterol levels in hepatocytes is dependent on LXRα and LDLR. Consistently, these effects on cholesterol levels by ch-13(c,t)-HpODE are diminished in LDLR or LXRα knockout mice. Together, our study provides evidence that elevated plasma cholesterol levels by CEOOHs are primarily due to the inhibition of cholesterol uptake in the liver and macrophages, which may play an important role in the pathogenesis of CVD.

Lysine glycation of apolipoprotein A-I impairs its anti-inflammatory function in type 2 diabetes mellitus.

Apolipoprotein A-I (apoA-I), the major protein compontent of high-density lipoprotein (HDL), exerts many anti-atherogenic functions. This study aimed to reveal whether nonenzymatic glycation of specific sites of apoA-I impaired its anti-inflammatory effects in type 2 diabetes mellitus (T2DM). LC-MS/MS was used to analyze the specific sites and the extent of apoA-I glycation either modified by glucose in vitro or isolated from T2DM patients. Cytokine release in THP-1 monocyte-derived macrophages was tested by ELISA. Activation of NF-kappa B pathway was detected by western blot. The binding affinity of apoA-I to THP-1 cells was measured using 125I-labeled apoA-I. We identified seven specific lysine (Lys, K) residues of apoA-I (K12, K23, K40, K96, K106, K107 and K238) that were susceptible to be glycated either in vitro or in vivo. Glycation of apoA-I impaired its abilities to inhibit the release of TNF-α and IL-1ß against lipopolysaccharide (LPS) in THP-1 cells. Besides, the glycation levels of these seven K sites in apoA-I were inversely correlated with its anti-inflammatory abilities. Furthermore, glycated apoA-I had a lower affinity to THP-1 cells than native apoA-I had. We generated mutant apoA-I (K107E, M-apoA-I) with a substitution of glutamic acid (Glu, E) for lysine at the 107th site, and found that compared to wild type apoA-I (WT-apoA-I), M-apoA-I decreased its anti-inflammatory effects in THP-1 cells. We also modeled the location of these seven K residues on apoA-I which allowed us to infer the conformational alteration of glycated apoA-I and HDL. In summary, glycation of these seven K residues altered the conformation of apoA-I and consequently impaired the protective effects of apoA-I, which may partly account for the increased risk of cardiovascular disease (CVD) in diabetic subjects.

Intracellular near-Infrared Microlaser Probes Based on Organic Microsphere-SiO2 Core-Shell Structures for Cell Tagging and Tracking.

Conventional near-infrared (NIR) luminescent probes, such as DsRed and Cy5, utilize spontaneous emission (SE) signals, which are broad (fwhm >50 nm) and often have low quantum yield. Herein, we developed smart NIR intracellular whispering-gallery mode (WGM) microlaser probes made by organic microspheres of (E)-3-(4-(diptolylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one (DPHP) coated with a silica shell. The overall small diameter ( D, adjustable between 2 and 10 µm) and the biocompatible silica shell ensure our core-shell microspheres (CSmSPs) to be engulfed in cells as a microlaser operating around 720 nm with a low threshold of 0.78 µJ/cm2. Considering that WGM mode spacing depending strongly on its size, it will be possible to distinguish millions of individual macrophages through well-defined WGM lasing peaks (fwhm ≤2 nm) of CSmSPs of different sizes. Furthermore, we monitored the transformation of normal macrophages to foamy ones by encoding them with our NIR CSmSPs microlaser probes, which deliver constant WGM lasing signals with a spectral fluctuation <0.02 nm and excellent stability.

Gut flora-dependent metabolite Trimethylamine-N-oxide accelerates endothelial cell senescence and vascular aging through oxidative stress.

Trimethylamine-N-oxide (TMAO), gut microbiota-dependent metabolites, has been shown to be associated with cardiovascular diseases. However, little is known about the relationship between TMAO and vascular aging. Here, we observed a change in TMAO during the aging process and the effects of TMAO on vascular aging and endothelial cell (EC) senescence. We analyzed age-related plasma levels of TMAO in young adults (18-44 years old), older adults (≥ 65 years old), and 1-month-old, 3-month-old, 6-month-old and 10-month-old senescence-accelerated mouse prone 8 (SAMP8) and age-matched senescence-accelerated mouse resistance 1 (SAMR1) models. We found that circulating TMAO increased with age both in humans and mice. Next, we observed that a TMAO treatment for 16 weeks induced vascular aging in SAMR1 mice and accelerated the process in SAMP8 mice, as measured by an upregulation of senescence markers including senescence-associated ß-galactosidase (SA-ß-gal), p53, and p21, vascular dysfunction and remodeling. In vitro, we demonstrated that prolonged TMAO treatment induced senescence in human umbilical vein endothelial cells (HUVECs), characterized by reduced cell proliferation, increased expressions of senescence markers, stagnate G0/G1, and impaired cell migration. Furthermore, TMAO suppressed sirtuin 1 (SIRT1) expression and increased oxidative stress both in vivo and in vitro and then activated the p53/p21/Rb pathway resulting in increased p53, acetylation of p53, p21, and decreased CDK2, cyclinE1, and phosphorylation of Rb. In summary, these data suggest that elevated circulating TMAO during the aging process may deteriorate EC senescence and vascular aging, which is probably associated with repression of SIRT1 expression and increased oxidative stress, and, thus, the activation of the p53/p21/Rb pathway.

Association of betaine with blood pressure in dialysis patients.

Mechanisms underlying elevated blood pressure in dialysis patients are complex as a variety of non-traditional factors are involved. We sought to explore the association of circulating betaine, a compound widely distributed in food, with blood pressure in dialysis patients. We used baseline data of an ongoing cohort study involving patients on hemodialysis. Plasma betaine was measured by high performance liquid chromatography in 327 subjects. Blood pressure level was determined by intradialytic ambulatory blood pressure monitoring. The mean age of the patients was 52.6 ± 11.9 years, and 58.4% were male. Average interdialytic ambulatory systolic and diastolic blood pressure were 138.4 ± 22.7 mm Hg and 84.4 ± 12.5 mm Hg, respectively. Mean plasma betaine level was 37.6 µmol/L. Multiple linear regression analysis revealed significant associations of betaine with both systolic blood pressure (ß = -3.66, P = .003) and diastolic blood pressure (ß = -2.00, P = .004). The associations persisted even after extensive adjustment for cardiovascular covariates. Subgroup analysis revealed that the association between betaine and blood pressure was mainly limited to female patients. Our data suggest that alteration of circulating betaine possibly contributes to blood pressure regulation in these patients.

Connexin43 and Myocardial Ischemia-Reperfusion Injury.

BACKGROUND: Recently, the treatment and prevention of ischemic cardiomyopathy is one of the emerging research topics in the cardiovascular field. Gap junction is the basic structure of cardiac electrophysiology. Connexin is the basic unit of gap junctions. Connexin43(CX43) is the most abundant member of Cx family in the heart, the normal expression of Cx43 is important for heart development, electrically coupled cardiomyocytes activities and coordination of myocardial function. The connection between Cx43 and myocardial ischemia/reperfusion or reperfusion injury has become the focus of current research. METHODS: We undertook a structured search of bibliographic database for peer-reviewed research literature using a focused review question and inclusion/exclusion criteria. The quality of retrieved papers was appraised using standard tools. The characteristics of screened papers were described, and a deductive qualitative content analysis methodology was applied to analyze the interventions and findings of included studies using a conceptual framework. RESULTS: Twenty-one papers were included in the review, eight papers outlined the relationship of Cx43 and reperfusion arrhythmias. Eight papers pointed out the effect on the infarct size of Cx43. CONCLUSION: The findings of this review confirm that Cx43 is the most abundant member of Cx family in the heart and is vital for myocardial protection during ischemia/reperfusion process and for ischemia/reperfusion injury. Many of its mechanism are still not very clear and require future research in the future.