Propofol protects against high glucose-induced endothelial adhesion molecules expression in human umbilical vein endothelial cells

Kaempferol protects gut-vascular barrier from high glucose-induced disorder via NF-κB pathway

Kaempferol is a natural edible flavonoid reported to treat high-fat diet-induced intestinal inflammation; however, the underlying molecular mechanisms remain unclear. This research aims to investigate the protective effect of kaempferol on the gut-vascular barrier (GVB) induced by high glucose and elucidate the underlying mechanism. Evans blue albumin efflux assay was used to test endothelial cell permeability. The results showed that kaempferol (50 μM) significantly reversed the high glucose-induced monolayer barrier permeability of rat intestinal microvascular endothelial cells (RIMVECs), while kaempferol significantly alleviated the high glucose-induced rarefication of the tight junction protein Claudin-5. Moreover, kaempferol also reduced high glucose-induced angiogenesis and cell migration via inhibiting the VEGFR2/p38 pathway. Kaempferol also protected against high glucose-induced overproduction of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 by inhibiting NF-κB p65 nuclear translocation. In addition, kaempferol had similar effects to the NF-κB inhibitor SN50 in reducing high glucose-induced ICAM-1 expression and endothelial barrier permeabilization. Our findings in part reveal the pathological mechanism of hyperglycemia-related gastrointestinal diseases and underlie the molecular mechanism of kaempferol in inhibiting bowel inflammation from a novel perspective.

Propofol protects against high glucose-mediated endothelial injury via inhibition of COX2 and iNOS expressions

Perioperative hyperglycemia is a common metabolic disorder in the clinic. Hyperglycemia, via upregulation of E74-like ETS transcription factor 3 (ELF3), induces cyclooxygenase 2 (COX2) and inducible nitric oxide synthase (iNOS) expressions, thus leading to endothelial apoptosis and vascular endothelial injury. Propofol is a widely used anesthetic. In the present study, we explored whether and how propofol protects against high glucose-induced COX2 and iNOS expressions in human umbilical vein endothelial cells (HUVECs). We found that high glucose level decreases cell viability and increases COX2 and iNOS expressions in HUVECs. Our data also indicated that ELF3 overexpression participates in high glucose-mediated cell viability reduction and high glucose-induced COX2 and iNOS expressions. Moreover, propofol treatment improves high glucose-mediated reduction in cell viability and decreases COX2 and iNOS expressions via inhibition of ELF3 expressions. Furthermore, specificity protein 1 (SP1) was found to regulate ELF3 expression, thus mediating endothelial injury. Propofol inhibits high glucose-induced SP1 expression. High glucose increases the abundance of SP1 bound to the ELF3 promoter, which can be reversed by propofol treatment. The protective effect of propofol is reversed by SP1 overexpression. In conclusion, propofol downregulates high glucose-induced SP1 expression, thus attenuating high glucose-induced ELF3 expression, inhibiting high glucose-induced COX2 and iNOS expressions, and improving high glucose-mediated cell viability reduction in HUVECs.

ETS proto-oncogene 1 modulates PTP1B expression to participate in high glucose-mediated endothelial inflammation

Hyperglycemia-induced endothelial inflammation participates in the pathogenesis of cardiovascular complications in diabetics. Previous studies showed that protein tyrosine phosphatase 1B (PTP1B) and ETS proto-oncogene 1 (ets1) are involved in hyperglycemia-induced endothelial inflammation. In this study, we hypothesized that ets1 modulates PTP1B expression, thus playing a crucial role in hyperglycemia-induced vascular endothelial inflammation. Our results indicated that high glucose increases monocyte/endothelial adhesion, vascular cell adhesion molecule-1 (VCAM-1) expression and p65 phosphorylation in human umbilical vein endothelial cells (HUVECs). Moreover, high glucose-mediated endothelial inflammation is reversed by PTP1B silencing. In addition, high glucose increases ets1 expression in HUVECs. silencing reverses high glucose-mediated endothelial inflammation. Furthermore, the effect of ets1 overexpression is similar to that of high glucose treatment, which is counteracted by si-PTP1B. The results from ChIP assays indicated that ets1 occupies the PTP1B promoter region. Ets1 overexpression enhances PTP1B promoter activity, which is disappeared after specific binding site mutation. experiments demonstrated that the expressions of VCAM-1, PTP1B, and ets1, as well as the phosphorylation of p65 are augmented in the aorta of diabetic rats. In conclusion, ets1 contributes to hyperglycemia-mediated endothelial inflammation via upregulation of PTP1B expression.

Important Functions and Molecular Mechanisms of Mitochondrial Redox Signaling in Pulmonary Hypertension

Mitochondria are important organelles that act as a primary site to produce reactive oxygen species (ROS). Additionally, mitochondria play a pivotal role in the regulation of Ca²⁺ signaling, fatty acid oxidation, and ketone synthesis. Dysfunction of these signaling molecules leads to the development of pulmonary hypertension (PH), atherosclerosis, and other vascular diseases. Features of PH include vasoconstriction and pulmonary artery (PA) remodeling, which can result from abnormal proliferation, apoptosis, and migration of PA smooth muscle cells (PASMCs). These responses are mediated by increased Rieske iron–sulfur protein (RISP)-dependent mitochondrial ROS production and increased mitochondrial Ca²⁺ levels. Mitochondrial ROS and Ca²⁺ can both synergistically activate nuclear factor κB (NF-κB) to trigger inflammatory responses leading to PH, right ventricular failure, and death. Evidence suggests that increased mitochondrial ROS and Ca²⁺ signaling leads to abnormal synthesis of ketones, which play a critical role in the development of PH. In this review, we discuss some of the recent findings on the important interactive role and molecular mechanisms of mitochondrial ROS and Ca²⁺ in the development and progression of PH. We also address the contributions of NF-κB-dependent inflammatory responses and ketone-mediated oxidative stress due to abnormal regulation of mitochondrial ROS and Ca²⁺ signaling in PH.

Effects of sevoflurane and propofol anesthesia on intraoperative endothelial cell function in patients undergoing laparoscopic cholecystectomy

Objectives

To investigate the effects of sevoflurane and propofol anesthesia on inflammatory or anti-inflammatory responses in patients undergoing laparoscopic cholecystectomy (LC).

Methods

Patients undergoing LC (n = 23) were divided into sevoflurane (S) (n = 11) and propofol (P) (n = 12) anesthesia groups. A blood sample was taken before induction (T0), after induction but before pneumoperitoneum (T1), 15 minutes after pneumoperitoneum (T2), immediately after extubation (T3), and 30 minutes after extubation (T4). P-selectin-positive platelets and intercellular cell adhesion molecule-1 (ICAM-1)-positive lymphocytes, and plasma P-selectin, ICAM-1 and thrombomodulin (TM) levels were analyzed.

Results

Sevoflurane significantly increased P-selectin expression in platelets at T2, T3, and T4 and in plasma at T1, T2, T3, and T4, but it did not affect ICAM-1 and TM. Propofol had no significant effects on P-selectin, ICAM-1, and TM expression during anesthesia and surgery. P-selectin, ICAM-1, and TM expression was higher in the S compared with P group at T1, T2, and T3 for platelet P-selectin; T2 and T4 for plasma P-selectin; T1 and T2 for lymphocyte ICAM-1; and T1, T2, and T3 for plasma TM.

Conclusions

Propofol anesthesia can delay the inflammatory reactions during laparoscopic surgery and better maintain the structure stability and function in vascular endothelial cells.

SET8 suppression mediates high glucose-induced vascular endothelial inflammation via the upregulation of PTEN

Hyperglycemia-mediated endothelial inflammation participates in the pathogenesis of cardiovascular complications in subjects with diabetes. Previous studies reported that phosphatase and tensin homolog deleted on chromosome ten (PTEN) and SET8 participate in high glucose-mediated endothelial inflammation. In this study, we hypothesize that SET8 regulates PTEN expression, thus contributing to high glucose-mediated vascular endothelial inflammation. Our data indicated that plasma soluble intercellular adhesion molecule-1 (sICAM-1) and endothelial selectin (e-selectin) were increased in patients with diabetes and diabetic rats. PTEN expression was augmented in the peripheral blood mononuclear cells of patients with diabetes and in the aortic tissues of diabetic rats. Our in vitro study indicated that high glucose increased monocyte/endothelial adhesion, endothelial adhesion molecule expression and p65 phosphorylation in human umbilical vein endothelial cells (HUVECs). Moreover, high glucose led to endothelial inflammation via upregulation of PTEN. Furthermore, high glucose inhibited SET8 expression and histone H4 lysine 20 methylation (H4K20me1), a downstream target of SET8. SET8 overexpression reversed the effects of high-glucose treatment. shSET8-mediated endothelial inflammation was counteracted by siPTEN. Furthermore, SET8 was found to interact with FOXO1. siFOXO1 attenuated high glucose-mediated endothelial inflammation. FOXO1 overexpression-mediated endothelial inflammation was counteracted by siPTEN. H4K20me1 and FOXO1 were enriched in the PTEN promoter region. shSET8 increased PTEN promoter activity and augmented the positive effect of FOXO1 overexpression on PTEN promoter activity. Our in vivo study indicated that SET8 was downregulated and FOXO1 was upregulated in the peripheral blood mononuclear cells of patients with diabetes and the aortic tissues of diabetic rats. In conclusion, SET8 interacted with FOXO1 to modulate PTEN expression in vascular endothelial cells, thus contributing to hyperglycemia-mediated endothelial inflammation.

High glucose levels in patients with diabetes trigger vascular inflammation by affecting the expression of key proteins in blood vessel linings. Elevated glucose causes inflammation of the endothelium, a thin layer of cells that lines blood and lymph vessels, leading to cardiovascular complications. The phosphatase and tensin homolog protein (PTEN) contributes to endothelial inflammation, but the precise mechanisms are unclear. Xuefang Shen at Fudan University in Shanghai, China, and co-workers demonstrated that elevated glucose increases PTEN expression, with increased levels of the protein found in peripheral blood cells of diabetic patients and aortic tissues of diabetic rats. In further experiments on rats, the researchers found that glucose also suppressed another protein called SET8, which contributed to increased PTEN levels. This suggests that SET8 is involved in PTEN modulation, and that both proteins influence vascular inflammation.

High glucose inhibits vascular endothelial Keap1/Nrf2/ARE signal pathway via downregulation of monomethyltransferase SET8 expression

Hyperglycemia-mediated reactive oxygen species (ROS) accumulation plays an important role in hyperglycemia-induced endothelial injury. Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway inhibition participates in hyperglycemia-induced ROS accumulation. Our previous study indicated that SET8 overexpression inhibits high glucose-mediated ROS accumulation in human umbilical vein endothelial cells (HUVECs). In the present study, we hypothesize that SET8 may play a major role in high glucose-induced ROS accumulation via modulation of Keap1/Nrf2/ARE pathway. Our data indicated that high glucose mediated cell viability reduction, ROS accumulation, and Nrf2/ARE signal pathway inhibition via upregulation of Keap1 expression in HUVECs. Moreover, high glucose inhibited the expressions of SET8 and H4K20me1 (a downstream target of SET8). SET8 overexpression improved high glucose-mediated Keap1/Nrf2/ARE pathway inhibition and endothelial oxidation. Consistently, the effects of sh-SET8 were similar to that of high glucose treatment and were reversed by si-Keap1. A mechanistic study found that H4K20me1 was enriched at the Keap1 promoter region. SET8 overexpression attenuated Keap1 promoter activity and its expression, while mutant SET8 R259G did not affect Keap1 promoter activity and expression. The results of this study demonstrated that SET8 negatively regulates Keap1 expression, thus participating in high glucose-mediated Nrf2/ARE signal pathway inhibition and oxidative injury in HUVECs.

High glucose mediates NLRP3 inflammasome activation via upregulation of ELF3 expression

Microtubule affinity regulating kinase 4 (MARK4) plays a crucial role in the regulation of NOD-like receptor pyrin domain 3 (NLRP3) inflammasome activation, which leads to the generation of bioactive interleukin (IL)-1β and IL-18. E74-like ETS transcription factor 3 (ELF3) participates in endothelial inflammatory processes. We hypothesized that ELF3 modulates MARK4 expression in vascular endothelial cells, thus contributing to high glucose-mediated NLRP3 inflammasome activation. Plasma IL-1β, IL-18, NLRP3 inflammasome and MARK4 expression was increased in diabetic patients and rats. An in vitro study indicated that high glucose increased IL-1β and IL-18 expression and activated the NLRP3 inflammasome via upregulation of MARK4 in human umbilical vein endothelial cells (HUVECs). Furthermore, high glucose increased ELF3 expression. ELF3 downregulation reversed the effects of high glucose treatment. Accordingly, the effects of ELF3 overexpression were similar to those of high glucose treatment and were counteracted by siMARK4. Furthermore, ELF3 was found to interact with SET8. High glucose inhibited SET8 expression and histone H4 lysine 20 methylation (H4K20me1), a downstream target of SET8. Overexpression of SET8 inhibited high glucose-induced MARK4 expression and NLRP3 inflammasome activation. The effects of shSET8 were similar to those of high glucose treatment and were counteracted by siMARK4. A mechanistic study found that ELF3 and H4K20me1 were enriched in the MARK4 promoter region. si-ELF3 attenuated MARK4 promoter activity and augmented the inhibitory effect of SET8 on MARK4 promoter activity. Furthermore, SET8 downregulation and ELF3 upregulation were confirmed in diabetic patients and rats. In conclusion, ELF3 interacted with SET8 to modulate MARK4 expression, which participated in hyperglycaemia-mediated endothelial NLRP3 inflammasome activation.

Ketamine attenuates high-glucose-mediated endothelial inflammation in human umbilical vein endothelial cells

Hyperglycemia mediates oxidative stress, thus inducing transcription factor nuclear factor kappa B (NF-κB) activation, increasing endothelial adhesion molecule expression and monocyte/endothelial interaction, and resulting in endothelial injury. Ketamine was reported to attenuate oxidative stress in many cases. In this research, we determined whether and how ketamine protects against high-glucose-mediated augmentation of monocyte/endothelial interaction and endothelial adhesion molecule expression in human umbilical vein endothelial cells. High glucose augmented monocyte/endothelial adhesion and endothelial adhesion molecule expression. High glucose induced reactive oxygen species (ROS) production and augmented phospho-protein kinase C (p-PKC) βII expression and PKC activity. Moreover, high glucose inhibited the inhibitory subunit of nuclear factor-κBα (IκBα) expression in the cytoplasm and induced NF-κB nuclear translocation. Importantly, the effects induced by high glucose were counteracted by ketamine treatment. Further, CGP53353, a PKC βII inhibitor, inhibited high-glucose-mediated NF-κB nuclear translocation, attenuated adhesion molecule expression, and reduced monocyte/endothelial interaction. Further, these effects of ketamine against high-glucose-induced endothelial injury were inhibited by phorbol 12-myristate 13-acetate, a PKC βII activator. In conclusion, ketamine, via reducing ROS accumulation, inhibited PKC βII Ser660 phosphorylation and PKC and NF-κB activation and reduced high-glucose-induced expression of endothelial adhesion molecules and monocyte/endothelial interaction.

High Glucose Induces Endothelial COX2 and iNOS Expression via Inhibition of Monomethyltransferase SETD8 Expression

Cyclooxygenase 2 (COX2) and inducible nitric oxide synthase (iNOS) overexpression results in endothelial apoptosis, thus mediating vascular endothelial injury in hyperglycaemia. E26 transformation-specific sequence transcription factor-1 (ESE-1), which belongs to the E26 transformation-specific family of transcription factors, has been demonstrated to be involved in COX2 and iNOS gene transcription. Our previous study indicated that SET domain-containing protein 8 (SETD8) downregulation is involved in high glucose-mediated endothelial inflammation in human umbilical vein endothelial cells (HUVECs). Here, we report that SETD8 plays a major role in hyperglycaemia-induced COX2 and iNOS expression. In HUVECs, upregulation of ESE-1 expression was related to high glucose-mediated apoptosis and COX2 and iNOS expression. High glucose inhibited SETD8 expression, and overexpression of SETD8 diminished the effects of high glucose treatment. Consistently, RNA silencing of SETD8 led to the opposite effect. Furthermore, SETD8 was found to interact with specificity protein 1 (SP1). Blockade of SP1 protected against high glucose-mediated endothelial injury. Mechanistically, we showed that H4K20me1, a downstream target of SETD8, and SP1 were enriched at the ESE-1 promoter region by ChIP assay. Luciferase reporter assays indicated that SETD8 overexpression attenuated ESE-1 promoter activity and augmented the inhibitory effect of siSP1 on ESE-1 promoter activity. In general, our data indicate that SETD8 interacts with SP1 to coregulate ESE-1 expression, which is involved in hyperglycaemia-mediated endothelial apoptosis in HUVECs.

Propofol attenuates high glucose-induced P66shc expression in human umbilical vein endothelial cells through Sirt1

Perioperative hyperglycemia is a common metabolic disorder in clinic settings. Hyperglycemia leads to endothelial inflammation, endothelial cell apoptosis, and dysfunction, thus resulting in endothelial injury. Propofol (2,6-diisopropylphenol) is a widely used intravenous anesthetic in clinic settings. Our previous study indicated that propofol inhibits mitochondrial reactive oxygen species (ROS) production via down-regulation of phosphatase A2 (PP2A) expression, inhibition of Ser36-p66shc dephosphorylation and mitochondrial translocation, thus improving high glucose-induced endothelial injury. The expression of p66shc was inhibited by propofol in hyperglycemic human umbilical vein endothelial cells (HUVECs). However, the mechanism by which propofol inhibits p66shc expression in hyperglycemic HUVECs is still obscure. In the present study, we mainly examined how propofol inhibited high glucose-induced p66shc expression in HUVECs. Compared with 5 mM glucose treatment, high glucose increased p66shc expression and decreased sirt1 expression, which was inhibited by propofol treatment. Moreover, EX527 (a sirt1 inhibitor) reversed the effect of propofol against high glucose-induced p66shc expression. However, EX527 did not reverse the effects of propofol against high glucose-induced ROS accumulation, endothelial inflammation, and apoptosis. Furthermore, when cells were incubated with propofol, EX527, and FTY720 (a PP2A activator) simultaneously, the effects of propofol against high glucose-induced ROS accumulation, inflammation, and apoptosis were reversed. Our results suggested that propofol inhibited high glucose-induced p66shc expression via upregulation of sirt1 expression in hyperglycemic HUVECs. Moreover, propofol protects against high glucose-mediated ROS accumulation and endothelial injury via both inhibition of p66shc expression and dephosphorylation of Ser36-p66shc.

Ethyl Rosmarinate Protects High Glucose-Induced Injury in Human Endothelial Cells

Ethyl rosmarinate (RAE) is one of the active constituents from Clinopodium chinense (Benth.) O. Kuntze, which is used for diabetic treatment in Chinese folk medicine. In this study, we investigated the protective effect of RAE on high glucose-induced injury in endothelial cells and explored its underlying mechanisms. Our results showed that both RAE and rosmarinic acid (RA) increased cell viability, decreased the production of reactive oxygen species (ROS), and attenuated high glucose-induced endothelial cells apoptosis in a dose-dependent manner, as evidenced by Hochest staining, Annexin V⁻FITC/PI double staining, and caspase-3 activity. RAE and RA both elevated Bcl-2 expression and reduced Bax expression, according to Western blot. We also found that LY294002 (phosphatidylinositol 3-kinase, or PI3K inhibitor) weakened the protective effect of RAE. In addition, PDTC (nuclear factor-κB, or NF-κB inhibitor) and SP600125 (c-Jun N-terminal kinase, or JNK inhibitor) could inhibit the apoptosis in endothelial cells caused by high glucose. Further, we demonstrated that RAE activated Akt, and the molecular docking analysis predicted that RAE showed more affinity with Akt than RA. Moreover, we found that RAE inhibited the activation of NF-κB and JNK. These results suggested that RAE protected endothelial cells from high glucose-induced apoptosis by alleviating reactive oxygen species (ROS) generation, and regulating the PI3K/Akt/Bcl-2 pathway, the NF-κB pathway, and the JNK pathway. In general, RAE showed greater potency than RA equivalent.

Propofol inhibits cell proliferation and invasion in rheumatoid arthritis fibroblast-like synoviocytes via the nuclear factor-κB pathway

Propofol is an anesthetic drug commonly used in the clinical practice. The aim of this study is to explore the effect of propofol on the aggressive behaviors of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs). Propofol treatment for 48 or 72 h significantly inhibited the viability of RA-FLSs, but a 24-h treatment did not produce cytotoxic effects. Propofol exposure for 48 h led to reduction of proliferation and induction of apoptosis in RA-FLSs, which was coupled with increased Bax and decreased Bcl-2 and survivin levels. Additionally, treatment with propofol for 24 h significantly suppressed the migration and invasion of RA-FLSs. Mechanistically, propofol inhibited nuclear factor-κB (NF-κB) activity. Overexpression of constitutively active NF-κB p65 reversed the inhibitory effects of propofol on RA-FLSs. Taken together, propofol exerts anti-proliferative and anti-invasive effects on RA-FLSs via the NF-κB pathway and may have therapeutic potential in treatment of RA.

Angiotensin-converting enzyme inhibitors attenuate propofol-induced pro-oxidative and antifibrinolytic effect in human endothelial cells

Introduction:

The aim of this study was to investigate the effects of plasma and tissue angiotensin-converting enzyme inhibitors (ACE-Is) against propofol-induced endothelial dysfunction and to elucidate the involved mechanisms in vitro.

Materials and methods:

We examined the effects of propofol (50 μM), quinaprilat and enalaprilat (10⁻⁵ M) on fibrinolysis (t-PA, PAI-1, TAFI antigen levels), oxidative stress parameters (H₂O₂ and MDA antigen levels and SOD and NADPH oxidase mRNA levels) and nitric oxide bioavailability (NO₂/NO₃ concentration and NOS expression at the level of mRNA) in human umbilical vein endothelial cells (HUVECs).

Results:

We found that both ACE-Is promoted similar endothelial fibrinolytic properties and decreased oxidative stress in vitro. Propofol alone increased the release of antifibrinolytic and pro-oxidative factors from the endothelium and increased mRNA iNOS expression. We also found that the incubation of HUVECs in the presence of propofol following ACE-Is pre-incubation caused weakness of the antifibrinolytic and pro-oxidative potential of propofol and this effect was similar after both ACE-Is.

Conclusions:

This observation suggests that the studied ACE-Is exerted protective effects against endothelial cell dysfunction caused by propofol, independently of hemodynamics.

Propofol inhibits high glucose-induced PP2A expression in human umbilical vein endothelial cells

Perioperative hyperglycemia is a common clinical metabolic disorder. Hyperglycemia could induce endothelial apoptosis, dysfunction and inflammation, resulting in endothelial injury. Propofol is a widely used anesthetic drug in clinical settings. Our previous studies indicated that propofol, via inhibiting high glucose-induced phosphatase A2 (PP2A) expression, attenuated high glucose-induced reactive oxygen species (ROS) accumulation, thus improving endothelial apoptosis, dysfunction and inflammation. However, the mechanisms by which propofol attenuated high glucose-induced PP2A expression is still obscure. In the present study, we examined how propofol attenuates high glucose-induced endothelial PP2A expression. Compared with 5mM glucose treatment, 15mM glucose up-regulated expression and activity of PP2A, increased cAMP response element binding protein (CREB), Ca²⁺-calmodulin dependent kinase II (CaMK II) phosphorylation and Ca²⁺ accumulation. More importantly, propofol decreased PP2A expression and activity, attenuated CREB, CaMK II phosphorylation and Ca²⁺ accumulation in a concentration-dependent manner. Moreover, we demonstrated that the effect of propofol was similar to that of MK801, an inhibitor of NMDA receptor. In contrast, rapastinel, an activator of NMDA receptor, antagonized the effect of propofol. Also, the effect of KN93, an inhibitor of CaMK II, was similar to that of propofol, except KN93 had no effect on 15mM glucose-mediated Ca²⁺ accumulation. Our data indicated that propofol, via inhibiting NMDA receptor, attenuated 15mM glucose-induced Ca²⁺ accumulation, CaMK II and CREB phosphorylation, thus inhibiting PP2A expression and improving 15mM glucose-induced endothelial dysfunction and inflammation.

Interpretation of metabolic memory phenomenon using a physiological systems model: What drives oxidative stress following glucose normalization?

Hyperglycemia is generally associated with oxidative stress, which plays a key role in diabetes-related complications. A complex, quantitative relationship has been established between glucose levels and oxidative stress, both in vitro and in vivo. For example, oxidative stress is known to persist after glucose normalization, a phenomenon described as metabolic memory. Also, uncontrolled glucose levels appear to be more detrimental to patients with diabetes (non-constant glucose levels) vs. patients with high, constant glucose levels. The objective of the current study was to delineate the mechanisms underlying such behaviors, using a mechanistic physiological systems modeling approach that captures and integrates essential underlying pathophysiological processes. The proposed model was based on a system of ordinary differential equations. It describes the interplay between reactive oxygen species production potential (ROS), ROS-induced cell alterations, and subsequent adaptation mechanisms. Model parameters were calibrated using different sources of experimental information, including ROS production in cell cultures exposed to various concentration profiles of constant and oscillating glucose levels. The model adequately reproduced the ROS excess generation after glucose normalization. Such behavior appeared to be driven by positive feedback regulations between ROS and ROS-induced cell alterations. The further oxidative stress-related detrimental effect as induced by unstable glucose levels can be explained by inability of cells to adapt to dynamic environment. Cell adaptation to instable high glucose declines during glucose normalization phases, and further glucose increase promotes similar or higher oxidative stress. In contrast, gradual ROS production potential decrease, driven by adaptation, is observed in cells exposed to constant high glucose.

Flow signaling and atherosclerosis

Atherosclerosis rarely develops in the region of arteries exposed to undisturbed flow (u-flow, unidirectional flow). Instead, atherogenesis occurs in the area exposed to disturbed flow (d-flow, multidirectional flow). Based on these general pathohistological observations, u-flow is considered to be athero-protective, while d-flow is atherogenic. The fact that u-flow and d-flow induce such clearly different biological responses in the wall of large arteries indicates that these two types of flow activate each distinct intracellular signaling cascade in vascular endothelial cells (ECs), which are directly exposed to blood flow. The ability of ECs to differentially respond to the two types of flow provides an opportunity to identify molecular events that lead to endothelial dysfunction and atherosclerosis. In this review, we will focus on various molecular events, which are differentially regulated by these two flow types. We will discuss how various kinases, ER stress, inflammasome, SUMOylation, and DNA methylation play roles in the differential flow response, endothelial dysfunction, and atherosclerosis. We will also discuss the interplay among the molecular events and how they coordinately regulate flow-dependent signaling and cellular responses. It is hoped that clear understanding of the way how the two flow types beget each unique phenotype in ECs will lead us to possible points of intervention against endothelial dysfunction and cardiovascular diseases.

High-density lipoprotein of patients with breast cancer complicated with type 2 diabetes mellitus promotes cancer cells adhesion to vascular endothelium via ICAM-1 and VCAM-1 upregulation

Adhesion of disseminating tumor cells to vascular endothelium is a pivotal starting point in the metastasis cascade. We have shown previously that diabetic high-density lipoprotein (HDL) has the capability of promoting breast cancer metastasis, and this report summarizes our more recent work studying the role of abnormal HDL in facilitating the adhesion of the circulating tumor cells to the endothelium. This is an initiating step in breast cancer metastasis, and this work assesses the role of ICAM-1 and VCAM-1 in this process. MDA-MB-231, MCF 7, and human umbilical vein endothelial cells (HUVECs) were treated with normal HDL from healthy controls (N-HDL), HDL from breast cancer patients (B-HDL), or HDL from breast cancer patients complicated with type 2 diabetes mellitus (BD-HDL), and the cell adhesion abilities were determined. ICAM-1 and VCAM-1 expression as well as the protein kinase C (PKC) activity were evaluated. The effect of PKC inhibitor and PKC siRNA on adhesion was also studied. The immunohistochemical staining of ICAM-1, VCAM-1, and E-selectin from breast cancer patients and breast cancer patients complicated with type 2 diabetes mellitus (T2DM) were examined. Our results indicate that BD-HDL promoted an increase in breast cancer cell adhesion to HUVECs and stimulated higher ICAM-1 and VCAM-1 expression on the cells surface of both breast cancer and HUVEC cells, along with the activation of PKC. Increased tumor cell (TC)-HUVEC adhesion, as well as ICAM-1 and VCAM-1 expression induced by BD-HDL, could be inhibited by staurosporine and PKC siRNA. In addition, a Db/db type 2 diabetes mouse model has more TC-Vascular Endothelium adhesion compared to a normal model. However, BD patients have a lower expression of ICAM-1, VCAM-1, and E-selectin in their tumor tissues. BD-HDL facilitates the adhesion of tumor cells to vascular endothelium by upregulating the expression of ICAM-1 and VCAM-1, thereby promoting the initial progression of breast cancer metastasis. This work indicates a prospective utilization of HDL-based strategies in the treatment of breast cancer patients with type 2 diabetes.

Puerarin Improves Diabetic Aorta Injury by Inhibiting NADPH Oxidase-Derived Oxidative Stress in STZ-Induced Diabetic Rats

OBJECTIVE

Puerarin is a natural flavonoid isolated from the TCM lobed kudzuvine root. This study investigated the effect and mechanisms of puerarin on diabetic aorta in rats.

METHODS

Streptozotocin- (STZ-) induced diabetic rats were administered with puerarin for 3 weeks. Levels of serum insulin (INS), PGE2, endothelin (ET), glycated hemoglobin (GHb), H2O2, and nitric oxide (NO) in rats were measured by ELISA and colorimetric assay kits. The aortas were stained with H&E. Moreover, the mRNA expression of ICAM-1, LOX-1, NADPH oxidase 2 (NOX2), and NOX4 and the protein expression of ICAM-1, LOX-1, NF-κB p65, E-selectin, NOX2, and NOX4 in aorta tissues were measured by real-time PCR and Western blot, respectively. The localization of ICAM-1, NF-κB p65, NOX2, and NOX4 in the aorta tissues was also determined through immunohistochemistry.

RESULTS

Puerarin treatment exerted no effect on fasting blood glucose levels but significantly reduced the serum levels of INS, GHb, PGE2, ET, H2O2, and NO. In addition, puerarin improved the pathological alterations and inhibited the expression of ICAM-1, LOX-1, NOX2, and NOX4 at both mRNA and protein levels. Puerarin also significantly reduced the number of cells showing positive staining for ICAM-1, NOX2, NOX4, and NF-κB p65.

CONCLUSION

Puerarin demonstrated protective effect on the STZ-induced diabetic rat aorta. The protective mechanisms may include regulation of NF-κB and inhibition of NOX2 and NOX4 followed by inhibition of cell adhesion molecule expression.

Vascular endothelial dysfunction and pharmacological treatment

The endothelium exerts multiple actions involving regulation of vascular permeability and tone, coagulation and fibrinolysis, inflammatory and immunological reactions and cell growth. Alterations of one or more such actions may cause vascular endothelial dysfunction. Different risk factors such as hypercholesterolemia, homocystinemia, hyperglycemia, hypertension, smoking, inflammation, and aging contribute to the development of endothelial dysfunction. Mechanisms underlying endothelial dysfunction are multiple, including impaired endothelium-derived vasodilators, enhanced endothelium-derived vasoconstrictors, over production of reactive oxygen species and reactive nitrogen species, activation of inflammatory and immune reactions, and imbalance of coagulation and fibrinolysis. Endothelial dysfunction occurs in many cardiovascular diseases, which involves different mechanisms, depending on specific risk factors affecting the disease. Among these mechanisms, a reduction in nitric oxide (NO) bioavailability plays a central role in the development of endothelial dysfunction because NO exerts diverse physiological actions, including vasodilation, anti-inflammation, antiplatelet, antiproliferation and antimigration. Experimental and clinical studies have demonstrated that a variety of currently used or investigational drugs, such as angiotensin-converting enzyme inhibitors, angiotensin AT1 receptors blockers, angiotensin-(1-7), antioxidants, beta-blockers, calcium channel blockers, endothelial NO synthase enhancers, phosphodiesterase 5 inhibitors, sphingosine-1-phosphate and statins, exert endothelial protective effects. Due to the difference in mechanisms of action, these drugs need to be used according to specific mechanisms underlying endothelial dysfunction of the disease.

Propofol protects against high glucose-induced endothelial apoptosis and dysfunction in human umbilical vein endothelial cells

BACKGROUND

Perioperative hyperglycemia is a common clinical metabolic disorder. Hyperglycemia could induce endothelial apoptosis and dysfunction. Propofol is a widely used IV anesthetic drug in clinical settings. In the present study, we examined whether and how propofol reduced high glucose-induced endothelial apoptosis and dysfunction in human umbilical vein endothelial cells (HUVECs).

METHODS

HUVECs were cultured with different concentrations (5, 10, 15, and 25 mM) of glucose for different times (4, 8, 12, and 24 hours). To study the effect of propofol, cells were incubated with different concentrations (0.2, 1, 5, and 25 μM) of propofol for 2 hours. In parallel experiments, cells were incubated in 5 mM glucose as control. Nitric oxide (NO) production was measured with a nitrate reductase assay. Cell viability was determined with a Cell Counting Kit-8. Protein expression of active caspase 3, cytochrome c, endothelial NO synthase (eNOS), p-eNOS-Thr, p66, protein kinase C βII (PKCβII), and p-PKCβII-Ser was measured by Western blot analysis. Accumulation of superoxide anion (O2˙) was measured with the reduction of ferricytochrome c. Cell apoptosis was determined with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining.

RESULTS

Compared with control, high glucose decreased NO production (P < 0.0001) and reduced cells viability (P < 0.0001) in HUVECs. Compared with high glucose treatment, pretreatment of cells with propofol (5 μM, 2 hours) reduced high glucose-induced inhibitory p-eNOS-Thr phosphorylation (P < 0.0001), increasing NO production (P = 0.0007), decreased high glucose-induced p66 expression (P < 0.0001) and p66 mitochondrial translocation (P < 0.0001), O2˙ accumulation (P < 0.0001), mitochondrial cytochrome c release (P < 0.0001), active caspase 3 expression (P < 0.0001), and enhancing endothelial viability (P < 0.0001). Furthermore, propofol inhibited high glucose-induced PKCβII expression (P = 0.0002) and p-PKCβII-Ser phosphorylation (P < 0.0001). Moreover, the observed protective effect of propofol was quite similar to that of PKCβII inhibitor.

CONCLUSIONS

Propofol, by a mechanism of decreasing high glucose-induced PKCβII expression and p-PKCβII-Ser phosphorylation, inhibits high glucose-induced p66 mitochondrial translocation, therefore protecting HUVECs from high glucose-induced endothelial dysfunction and apoptosis.

The ATP Receptors P2X7 and P2X4 Modulate High Glucose and Palmitate-Induced Inflammatory Responses in Endothelial Cells

Endothelial cells lining the blood vessels are principal players in vascular inflammatory responses. Dysregulation of endothelial cell function caused by hyperglycemia, dyslipidemia, and hyperinsulinemia often result in impaired vasoregulation, oxidative stress, inflammation, and altered barrier function. Various stressors including high glucose stimulate the release of nucleotides thus initiating signaling via purinergic receptors. However, purinergic modulation of inflammatory responses in endothelial cells caused by high glucose and palmitate remains unclear. In the present study, we investigated whether the effect of high glucose and palmitate is mediated by P2X7 and P2X4 and if they play a role in endothelial cell dysfunction. Transcript and protein levels of inflammatory genes as well as reactive oxygen species production, endothelial-leukocyte adhesion, and cell permeability were investigated in human umbilical vein endothelial cells exposed to high glucose and palmitate. We report high glucose and palmitate to increase levels of extracellular ATP, expression of P2X7 and P2X4, and inflammatory markers. Both P2X7 and P2X4 antagonists inhibited high glucose and palmitate-induced interleukin-6 levels with the former having a significant effect on interleukin-8 and cyclooxygenase-2. The effect of the antagonists was confirmed with siRNA knockdown of the receptors. In addition, P2X7 mediated both high glucose and palmitate-induced increase in reactive oxygen species levels and decrease in endothelial nitric oxide synthase. Blocking P2X7 inhibited high glucose and palmitate-induced expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 as well as leukocyte-endothelial cell adhesion. Interestingly, high glucose and palmitate enhanced endothelial cell permeability that was dependent on both P2X7 and P2X4. Furthermore, antagonizing the P2X7 inhibited high glucose and palmitate-mediated activation of p38-mitogen activated protein kinase. These findings support a novel role for P2X7 and P2X4 coupled to induction of inflammatory molecules in modulating high glucose and palmitate-induced endothelial cell activation and dysfunction.

Endothelial Na+/H+ exchanger NHE1 participates in redox-sensitive leukocyte recruitment triggered by methylglyoxal

Background

Excessive levels of methylglyoxal (MG) encountered in diabetes foster enhanced leukocyte-endothelial cell interactions, mechanisms of which are incompletely understood. MG genomically upregulates endothelial serum- and glucocorticoid-inducible kinase 1 (SGK1) which orchestrates leukocyte recruitment by regulating the activation and expression of transcription factors and adhesion molecules. SGK1 regulates a myriad of ion channels and carriers including the Na⁺/H⁺ exchanger NHE1. Here, we explored the effect of MG on SGK1-dependent NHE1 activation and the putative role of NHE1 activation in MG-induced leukocyte recruitment and microvascular hyperpermeability.

Methods

Using RT-PCR and immunoblotting, we analyzed NHE1 mRNA and protein levels in murine microvascular SVEC4-10EE2 endothelial cells (EE2 ECs). NHE1 phosphorylation was detected using a specific antibody against the 14-3-3 binding motif at phospho-Ser⁷⁰³. SGK in EE2 ECs was silenced using targeted siRNA. ROS production was determined using DCF-dependent fluorescence. Leukocyte recruitment and microvascular permeability in murine cremasteric microvasculature were measured using intravital microscopy. The expression of endothelial adhesion molecules was determined by immunoblotting and confocal imaging analysis.

Results

MG treatment significantly upregulated NHE1 mRNA and dose-dependently increased total- and phospho-NHE1. Treatment with SGK1 inhibitor GSK650394, antioxidant Tempol and silencing SGK all blunted MG-triggered phospho-NHE1 upregulation in EE2 ECs. NHE1 inhibitor cariporide attenuated MG-triggered ROS production, leukocyte adhesion and emigration and microvascular hyperpermeability, without affecting leukocyte rolling. Cariporide treatment did not alter MG-triggered upregulation of P- and E-selectins, but reduced endothelial ICAM-1 expression.

Conclusion

MG elicits SGK1-dependent activation of endothelial Na⁺/H⁺ exchanger NHE1 which participates in MG-induced ROS production, upregulation of endothelial ICAM-1, leukocyte recruitment and microvascular hyperpermeability. Pharmacological inhibition of NHE1 attenuates the proinflammatory effects of excessive MG and may, thus, be beneficial in diabetes-associated inflammation.

Propofol inhibits lipopolysaccharide-induced tumor necrosis factor-alpha expression and myocardial depression through decreasing the generation of superoxide anion in cardiomyocytes

TNF-α has been shown to be a major factor responsible for myocardial depression in sepsis. The aim of this study was to investigate the effect of an anesthetic, propofol, on TNF-α expression in cardiomyocytes treated with LPS both in vivo and in vitro. In cultured cardiomyocytes, compared with control group, propofol significantly reduced protein expression of gp91phox and phosphorylation of extracellular regulated protein kinases 1/2 (ERK1/2) and p38 MAPK, which associates with reduced TNF-α production. In in vivo mice studies, propofol significantly improved myocardial depression and increased survival rate of mice after LPS treatment or during endotoxemia, which associates with reduced myocardial TNF-α production, gp91phox, ERK1/2, and p38 MAPK. It is concluded that propofol abrogates LPS-induced TNF-α production and alleviates cardiac depression through gp91phox/ERK1/2 or p38 MAPK signal pathway. These findings have great clinical importance in the application of propofol for patients enduring sepsis.

The Effects of Propofol and Isoflurane on Blood Glucose during Abdominal Hysterectomy in Diabetic Patients

BACKGROUND

Acute hyperglycemia in the perioperative period is associated with significantly increased complications. In few human studies the effects of propofol and inhalational anesthetic on the glucose metabolism were compared. In this study we evaluated the effect of propofol and isoflurane on blood glucose during abdominal hysterectomy in diabetic patients.

METHODS

After approval by the Ethical Committee and written informed consent, thirty 35 to 65 years old diabetic women underwent for elective abdominal hysterectomy under general anesthesia were studied in this randomized single blind clinical trial study. The plasma glucose was maintained at 100 to 180 mg/dL during the operation. Anesthesia protocol was similar in two groups except maintenance of anesthesia that was with infusion of propofol in the propofol group and with isoflurane in the isoflurane group. Blood glucose level and the rate of insulin intake during surgery compared between two groups.

RESULTS

Mean blood glucose before induction of anesthesia did not have significant difference between two groups, but 60 and 90 minutes after starting the operation blood glucose in the propofol group was significantly lower than isoflurane group. Also with using Repeated Measure test, two groups was significantly different according to blood glucose (P=0.045). Mean of administration of insulin during the surgery did not have significant difference between two groups by using repeated measure test and P=0.271. Also mean of bispectral index in different times during the surgery between two groups didn't have significant difference (P=0.35 repeated measure test).

CONCLUSION

Blood glucose increased during maintenance of anesthesia with isoflurane compared to propofol during the surgery.

p38 mitogen-activated protein kinase is involved in arginase-II-mediated eNOS-uncoupling in obesity

Background

Endothelial nitric oxide synthase (eNOS)-uncoupling links obesity-associated insulin resistance and type-II diabetes to the increased incidence of cardiovascular disease. Studies have indicated that increased arginase is involved in eNOS-uncoupling through competing with the substrate L-arginine. Given that arginase-II (Arg-II) exerts some of its biological functions through crosstalk with signal transduction pathways, and that p38 mitogen-activated protein kinase (p38mapk) is involved in eNOS-uncoupling, we investigated here whether p38mapk is involved in Arg-II-mediated eNOS-uncoupling in a high fat diet (HFD)-induced obesity mouse model.

Methods

Obesity was induced in wild type (WT) and Arg-II-deficient (Arg-II^-/-) mice on C57BL/6 J background by high-fat diet (HFD, 55% fat) for 14 weeks starting from age of 7 weeks. The entire aortas were isolated and subjected to 1) immunoblotting analysis of the protein level of eNOS, Arg-II and p38mapk activation; 2) arginase activity assay; 3) endothelium-dependent and independent vasomotor responses; 4) en face staining of superoxide anion and NO production with Dihydroethidium and 4,5-Diaminofluorescein Diacetate, respectively, to assess eNOS-uncoupling. To evaluate the role of p38mapk, isolated aortas were treated with p38mapk inhibitor SB203580 (10 μmol/L, 1 h) prior to the analysis. In addition, the role of p38mapk in Arg-II-induced eNOS-uncoupling was investigated in cultured human endothelial cells overexpressing Arg-II in the absence or presence of shRNA against p38mapk.

Results

HFD enhanced Arg-II expression/activity and p38mapk activity, which was associated with eNOS-uncoupling as revealed by decreased NO and enhanced L-NAME-inhibitable superoxide in aortas of WT obese mice. In accordance, WT obese mice revealed decreased endothelium-dependent relaxations to acetylcholine despite of higher eNOS protein level, whereas Arg-II^-/- obese mice were protected from HFD-induced eNOS-uncoupling and endothelial dysfunction, which was associated with reduced p38mapk activation in aortas of the Arg-II^-/- obese mice. Moreover, overexpression of Arg-II in human endothelial cells caused eNOS-uncoupling and augmented p38mapk activation. The Arg-II-induced eNOS-uncoupling was prevented by silencing p38mapk. Furthermore, pharmacological inhibition of p38mapk recouples eNOS in isolated aortas from WT obese mice.

Conclusions

Taking together, we demonstrate here for the first time that Arg-II causes eNOS-uncoupling through activation of p38 mapk in HFD-induced obesity.

Myocardial blood flow under general anaesthesia with sevoflurane in type 2 diabetic patients: a pilot study

Background

In type 2 diabetic patients, cardiac events in the perioperative period may be associated with diminished myocardial vasomotor function and endothelial dysfunction. The influence of sevoflurane anaesthesia on myocardial endothelial dysfunction in type 2 diabetic mellitus is investigated in this pilot study.

Methods

Six males with type 2 diabetes mellitus and eight healthy controls were included. Using myocardial contrast echocardiography, myocardial blood flow (MBF) was measured at rest, during adenosine-induced hyperaemia (endothelium-independent vasodilation) and after sympathetic stimulation by the cold pressor test (endothelium-dependent vasodilation). Measurements were performed before and after induction of sevoflurane anaesthesia.

Results

Sevoflurane anaesthesia decreased resting MBF in diabetics but not in controls (P = 0.03), while baseline MBF did not differ between diabetics and controls. Without anaesthesia, adenosine-induced hyperaemia increased MBF in both groups compared to resting values. Adenosine combined with sevoflurane resulted in a lower hyperaemic MBF in both groups compared to no anaesthesia. Differences in MBF in response to adenosine before and after sevoflurane administration were larger in diabetic patients, however not statistically significant in this pilot group (P = 0.08). Myocardial blood flow parameters after the cold pressor test were not different between groups.

Conclusion

These pilot data in type 2 diabetic patients show that sevoflurane anaesthesia decreases resting myocardial blood flow compared to healthy controls. Further, we observed a trend towards a lower endothelium-independent vasodilation capacity in diabetic patients under sevoflurane anaesthesia. Endothelium-dependent vasodilation was not affected by sevoflurane in diabetic patients. These data provide preliminary insight into myocardial responses in type 2 diabetic patients under general anaesthesia.

Trial registration

http://www.clinicialtrials.gov, NCT00866801

Vaspin inhibits cytokine-induced nuclear factor-kappa B activation and adhesion molecule expression via AMP-activated protein kinase activation in vascular endothelial cells

Background

Vaspin is an adipocytokine that was recently identified in the visceral adipose tissue of diabetic rats and has anti-diabetic and anti-atherogenic effects. We hypothesized that vaspin prevents inflammatory cytokine-induced nuclear factor-kappa B (NF-κB) activation by activating AMP-activated protein kinase (AMPK) in vascular endothelial cells.

Methods

We examined the effects of vaspin on NF-κB activation and the expression of the NF-κB-mediated genes intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and monocyte chemoattractant protein-1 (MCP-1). Human aortic endothelial cells (HAECS) were used. Tumor necrosis factor alpha (TNFα) was used as a representative proinflammatory cytokine.

Results

Treatment with vaspin significantly increased the phosphorylation of AMPK and acetyl-CoA carboxylase, the down-stream target of AMPK. Furthermore, treatment with vaspin significantly decreased TNFα-induced activation of NF-κB, as well as the expression of the adhesion molecules ICAM-1, VCAM-1, E-selectin, and MCP-1. These effects were abolished following transfection of AMPKα1-specific small interfering RNA. In an adhesion assay using THP-1 cells, vaspin reduced TNFα-induced adhesion of monocytes to HAECS in an AMPK-dependent manner.

Conclusions

Vaspin might attenuate the cytokine-induced expression of adhesion molecule genes by inhibiting NF-κB following AMPK activation.