Neutrophil-endothelial cells modulation in diabetic patients undergoing coronary artery bypass grafting

Surface markers on microparticles involved in obesity-derived diseases

AIMS

This review aimed to investigate the different types of microparticles playing role in obesity-related diseases. Additionally, the factors participating in changing the microparticles amount in obese people will also be discussed.

MATERIAL & METHODS

The authors collected the relevant articles published until 2023 and these are carefully selected from three scientific databases based on keywords.

KEY FINDINGS

It has been revealed that exercise might change the microparticle content in the body. The other factor which participates in obesity process is the oxidative stress which is increased in microparticles. Moreover, the obesity is implicated in metabolic conditions including diabetes and cardiovascular diseases.

SIGNIFICANCE

More than one-third of people on the planet today are known as overweight individuals. Microparticles (MPs) are small membrane-bound vesicles that are found in healthy people's blood and are elevated in patients with pathological conditions such as obesity. MPs mostly come from platelets, leukocytes, endothelial cells, and vascular smooth muscle cells. Considering the effect of obesity on microparticles, these small membrane-bound vesicles might play a crucial role in preventing or treatment of obesity.

Type 1 diabetes mellitus: Roles of neutrophils in the pathogenesis

Circulating neutrophil counts are reduced both in healthy autoantibody-positive individuals and in patients with type 1 diabetes, which may be related on cell-specific autoimmunity. This paper was written to give an update on roles of neutrophils in the pathogenesis of type 1 diabetes mellitus. Different research search engines like PubMed Central, Scopus, Web of Science, Researchgate, Google Scholar etc were utilised for writing this paper. A drop in blood neutrophil counts in type 1 diabetes may be caused by decreased neutrophil generation and maturation, tissue maintenance, consumption, or peripheral damage. Neutrophil count variations between studies may be explained by results from various stages of diabetes or by ethnic groups. Neutrophils can induce type 1 diabetes by colonizing pancreatic islets and interacting with other immune cells, according to exciting findings that shed new light on their role in the pathogenesis of the disease. Knowing more about the function of neutrophils in the pathogenesis of type 1 diabetes will help in early diagnosis, treatment, and even prevention of the disease.

A Bittersweet Response to Infection in Diabetes; Targeting Neutrophils to Modify Inflammation and Improve Host Immunity

Chronic and recurrent infections occur commonly in both type 1 and type 2 diabetes (T1D, T2D) and increase patient morbidity and mortality. Neutrophils are professional phagocytes of the innate immune system that are critical in pathogen handling. Neutrophil responses to infection are dysregulated in diabetes, predominantly mediated by persistent hyperglycaemia; the chief biochemical abnormality in T1D and T2D. Therapeutically enhancing host immunity in diabetes to improve infection resolution is an expanding area of research. Individuals with diabetes are also at an increased risk of severe coronavirus disease 2019 (COVID-19), highlighting the need for re-invigorated and urgent focus on this field. The aim of this review is to explore the breadth of previous literature investigating neutrophil function in both T1D and T2D, in order to understand the complex neutrophil phenotype present in this disease and also to focus on the development of new therapies to improve aberrant neutrophil function in diabetes. Existing literature illustrates a dual neutrophil dysfunction in diabetes. Key pathogen handling mechanisms of neutrophil recruitment, chemotaxis, phagocytosis and intracellular reactive oxygen species (ROS) production are decreased in diabetes, weakening the immune response to infection. However, pro-inflammatory neutrophil pathways, mainly neutrophil extracellular trap (NET) formation, extracellular ROS generation and pro-inflammatory cytokine generation, are significantly upregulated, causing damage to the host and perpetuating inflammation. Reducing these proinflammatory outputs therapeutically is emerging as a credible strategy to improve infection resolution in diabetes, and also more recently COVID-19. Future research needs to drive forward the exploration of novel treatments to improve infection resolution in T1D and T2D to improve patient morbidity and mortality.

Neutrophils in type 1 diabetes

Type 1 diabetes is an autoimmune disease that afflicts millions of people worldwide. It occurs as the consequence of destruction of insulin-producing pancreatic β-cells triggered by genetic and environmental factors. The initiation and progression of the disease involves a complicated interaction between β-cells and immune cells of both innate and adaptive systems. Immune cells, such as T cells, macrophages and dendritic cells, have been well documented to play crucial roles in type 1 diabetes pathogenesis. However, the particular actions of neutrophils, which are the most plentiful immune cell type and the first immune cells responding to inflammation, in the etiology of this disease might indeed be unfairly ignored. Progress over the past decades shows that neutrophils might have essential effects on the onset and perpetuation of type 1 diabetes. Neutrophil-derived cytotoxic substances, including degranulation products, cytokines, reactive oxygen species and extracellular traps that are released during the process of neutrophil maturation or activation, could cause destruction to islet cells. In addition, these cells can initiate diabetogenic T cell response and promote type 1 diabetes development through cell-cell interactions with other immune and non-immune cells. Furthermore, relevant antineutrophil therapies have been shown to delay and dampen the progression of insulitis and autoimmune diabetes. Here, we discuss the relationship between neutrophils and autoimmune type 1 diabetes from the aforementioned aspects to better understand the roles of these cells in the initiation and development of type 1 diabetes.

Impact of Endothelial Activation on Infective and Inflammatory Complications after Cardiac Surgery in type II Diabetes Mellitus

Purpose

Altered endothelial response has been described in diabetics after cardiac surgery. Infections and inflammatory organ damage often complicate the postoperative course. We evaluated endothelial/cytokine response (ECR) after cardiac surgery and its role on infective/inflammatory complications of type II diabetic patients.

Methods

Perioperative ECR of 60 diabetic patients (Group A) undergoing cardiopulmonary bypass was compared to that of 60 non-diabetics (Group B). Hemodynamics, endothelial markers [vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1)], pro-inflammatory (IL-2, IL-6, IL-8) and anti-inflammatory cytokines (IL-10) were analyzed preoperatively (T0), at time of aortic declamping (T1), at ITU admission (T2), at 12 h (T3) and 24 h (T4) postoperatively. Postoperative infective/inflammatory complications were registered, and the related ECR was analyzed.

Results

Hemodynamics were comparable. No differences were found in perioperative IL-6 (p=0.776) and IL-8 (p=0.660) between the 2 groups. However, the diabetics showed significantly higher endothelial activation (VEGF p=0.0001, p=0.0001 since T1 to T3; MCP-1 p=0.0001, p<0.007 at T1, T3 and T4) with lower IL-10 (p=0.0001, p<0.05 at T2, T3, T4) and lower IL-2 secretion (p=0.0001, p<0.0001 at T1, T2). Infections developed in 23.3% of the diabetics; inflammatory complications in 13.3%. Those developing infections showed significantly lower IL-2 (p=0.042; p ≤. 021 at T1 and T2) than patients without infections, whereas those with complicated inflammatory lung or renal injury had higher MCP-1 leakage (p=0.006) with lower IL-10 (p=0.005).

Conclusions

The diabetics showed higher endothelial activation and lower antiinflammatory response to CPB compared to non-diabetics. Infections in diabetic patients correlated with depressed IL-2, while inflammatory complications correlated to higher endothelial activation and lower anti-inflammatory cytokine secretion.

Advanced glycation end products in diabetic patients with optimized glycaemic control and their effects on endothelial reactivity: possible implications in venous graft failure

BACKGROUND

Diabetic patients exhibit an increased risk of saphenous graft occlusion after coronary bypass. Advanced glycation end products (AGEs) are ubiquitous signalling proteins that are associated with vascular and neurological complication of diabetes. The aim of this study is to verify whether AGE levels may promote endothelial cell alterations responsible for vein graft failure.

METHODS

Segments of saphenous vein were obtained from both normal people and diabetic patients (HbA(1c) < 6.0%) at the time of coronary surgery. Cultured endothelial cells were incubated in the absence/presence of AGEs (2 and 20 microM), and mRNA and protein for both receptor of AGEs (RAGE) and peroxisome proliferator-activated receptors-gamma (PPAR-gamma) were analysed by real-time polymerised chain reaction (PCR) and Western blot analysis. In the same fashion, the cell release of reactive oxygen species (ROS) was estimated in the absence/presence of AGEs by spectrofluorimetric analysis. Finally, neutrophil-endothelial adhesion was evaluated in saphenous vein segments with and without the addition of AGEs.

RESULTS

AGEs activated in a dose-dependent manner the expression of RAGE and inhibited PPAR-gamma expression in endothelial cells as testified by both reverse transcription-PCR (RT-PCR) and Western blot analysis. Stimulation of cultured endothelial cells with AGEs significantly enhanced intracellular ROS formation in a dose-dependent manner. Finally, neutrophil-endothelial adhesion was significantly increased after incubation of control veins with AGEs.

CONCLUSIONS

These findings indicate that even in diabetic patients with HbA(1c) < 6.0%, elevated serum levels of AGE determine a sort of a pro-thrombotic state, providing a common mechanism that could explain the increased rate of vein graft occlusion in this population.

Differences in gene expression profiles of diabetic and nondiabetic patients undergoing cardiopulmonary bypass and cardioplegic arrest

BACKGROUND

Diabetes mellitus is an independent risk factor for early postoperative mortality and complications after coronary artery bypass grafting (CABG). We sought to compare the cardiac gene expression responses to cardiopulmonary bypass (CPB) and cardioplegic arrest (C) in patients with and without diabetes.

METHODS AND RESULTS

Twenty atrial myocardium samples were harvested from 5 type II insulin-dependent diabetic and 5 matched nondiabetic patients undergoing CABG, before and after CPB/C. Oligonucleotide microarray analyses of 12625 genes were performed on the 10 sample pairs using matched pre-CPB tissues as controls. Array results were validated with Northern blotting and immunoblotting. Compared with pre-CPB/C, post-CPB/C myocardial tissues revealed 851 upregulated and 480 downregulated genes with a threshold P< or =0.025 (signal-to-noise ratio, 4.04) in the diabetic group, compared with 480 upregulated and 626 downregulated genes (signal-to-noise ratio, 3.04) in the nondiabetic group (P<0.001). There were 18 genes that were upregulated >4-fold in diabetic and nondiabetic patients (including inflammatory/transcription activators FOS, CYR 61, and IL-6, apoptotic gene NR4A1, stress gene DUSP1, and glucose-transporter gene SLC2A3). However, 28 genes showed such marked upregulation in the diabetic group exclusively (including inflammatory/transcription activators MYC, IL8, IL-1beta, growth factor vascular endothelial growth factor, amphiregulin, and glucose metabolism-involved gene insulin receptor substrate 1), and 27 genes in the nondiabetic group only, including glycogen-binding subunit PPP1R3C.

CONCLUSIONS

Gene expression profile after CPB/C is quantitatively and qualitatively different in patients with diabetes. These results have important implications for the design of tailored myocardial protection and operative strategies for diabetic patients undergoing CPB/C.

Lipaemia, Inflammation and Atherosclerosis

Atherosclerosis is the major cause of death in the world. Fasting and postprandial hyperlipidaemia are important risk factors for coronary heart disease (CHD). Recent developments have undoubtedly indicated that inflammation is pathophysiologically closely linked to atherogenesis and its clinical consequences. Inflammatory markers such as C-reactive protein (CRP), leucocyte count and complement component 3 (C3) have been linked to CHD and to hyperlipidaemia and several other CHD risk factors. Increases in these markers may result from activation of endothelial cells (CRP, leucocytes, C3), disturbances in adipose tissue fatty acid metabolism (CRP, C3), or from direct effects of CHD risk factors (leucocytes). It has been shown that lipoproteins, triglycerides, fatty acids and glucose can activate endothelial cells, most probably as a result of the production of reactive oxygen species. Similar mechanisms may also lead to leucocyte activation. Increases in triglycerides, fatty acids and glucose are common disturbances in the metabolic syndrome and are most prominent in the postprandial phase. People are in a postprandial state most of the day, and this phase is proatherogenic. Inhibition of the activation of leucocytes, endothelial cells, or both, is an interesting target for intervention, as activation is obligatory for adherence of leucocytes to the endothelium, thereby initiating atherogenesis. Potential interventions include the use of unsaturated long-chain fatty acids, polyphenols, antioxidants, angiotensin converting enzyme inhibitors and high-dose aspirin, which have direct anti-inflammatory and antiatherogenic effects. Furthermore, peroxisome proliferator activating receptor gamma (PPARgamma) agonists and statins have similar properties, which are in part independent of their lipid-lowering effects.

Glucose enhances endothelial LOX-1 expression: role for LOX-1 in glucose-induced human monocyte adhesion to endothelium

Endothelial dysfunction is an early and key determinant of diabetic vascular complications that is elicited at least in part by oxidized LDL (oxLDL). The recent observation that lectin-like oxLDL receptor-1 (LOX-1) expression is increased in the vascular endothelium of diabetic rats suggests a role for LOX-1 in the pathogenesis of diabetic vascular dysfunction. Because postprandial plasma glucose has been recently proposed as an independent risk factor for cardiovascular diseases in patients with diabetes, we evaluated, in the current study, the in vitro effect of high glucose on LOX-1 expression by human aortic endothelial cells (HAECs) and the role of this receptor in glucose-induced human monocyte adhesion to endothelium. Exposure of HAECs to high D-glucose concentrations (5.6-30 mmol/l) enhanced, in a dose- and time-dependent manner, LOX-1 expression, both at the gene and protein levels. The stimulatory effect of glucose on LOX-1 gene expression in HAECs was abolished by antioxidants and inhibitors of nuclear factor (NF)-kappaB, protein kinase C (PKC), and mitogen-activated protein kinases (MAPKs). Electrophoretic mobility shift assay data demonstrated that high glucose enhanced, in HAECs, the nuclear protein binding to the NF-kappaB regulatory element of the LOX-1 gene. Finally, our results showed that incubation of HAECs with high glucose increased human monocyte adhesion to endothelium through a LOX-1-dependent signaling mechanism. Overall, these results demonstrate that high glucose induces endothelial LOX-1 expression. This effect appears to be exerted at the transcriptional level through increased oxidant stress and NF-kappaB, PKC, and MAPK activation. The study also suggests a role for LOX-1 as mediator of the stimulatory effect of high glucose on monocyte adhesion.

Type 1 and type 2 diabetic patients display different patterns of cellular microparticles

The development of vasculopathies in diabetes involves multifactorial processes including pathological activation of vascular cells. Release of microparticles by activated cells has been reported in diseases associated with thrombotic risk, but few data are available in diabetes. The aim of the present work was to explore the number and the procoagulant activity of cell-derived microparticles in type 1 and 2 diabetic patients. Compared with age-matched control subjects, type 1 diabetic patients presented significantly higher numbers of platelet and endothelial microparticles (PMP and EMP), total annexin V-positive blood cell microparticles (TMP), and increased levels of TMP-associated procoagulant activity. In type 2 diabetic patients, only TMP levels were significantly higher without concomitant increase of their procoagulant activity. Interestingly, in type 1 diabetic patients, TMP procoagulant activity was correlated with HbA(1c), suggesting that procoagulant activity is associated with glucose imbalance. These results showed that a wide vesiculation process, resulting from activation or apoptosis of several cell types, occurs in diabetes. However, diabetic patients differ by the procoagulant activity and the cellular origin of microparticles. In type 1 diabetic patients, TMP-procoagulant activity could be involved in vascular complications. Moreover, its correlation with HbA(1c) reinforces the importance of an optimal glycemic control in type 1 diabetes.

Pulmonary dysfunction after cardiac surgery

Postoperative lung injury is one of the most frequent complications of cardiac surgery that impacts significantly on health-care expenditures and largely has been believed to result from the use of cardiopulmonary bypass (CPB). However, recent comparative studies between conventional and off-pump coronary artery bypass grafting have indicated that CPB itself may not be the major contributor to the development of postoperative pulmonary dysfunction. In our study, we review the associated physiologic, biochemical, and histologic changes, with particular reference to the current understanding of underlying mechanisms. Intraoperative modifications aiming at limiting lung injury are discussed. The potential benefits of maintaining ventilation and pulmonary artery perfusion during CPB warrant further investigation.

The systemic factor: the comparative roles of cardiopulmonary bypass and off-pump surgery in the genesis of patient injury during and following cardiac surgery

There is compelling evidence that off-pump coronary artery bypass operations are associated with reduced circulating levels of inflammatory mediators. Whereas complement activation and release of acute-phase reactants such as interleukin-6 are still expected to occur as consequences of a nonbypass-related general surgical trauma, a major feature of off-pump surgery seems to be a decreased production of interleukin-8, which may have important practical implications because of the participation of this cytokine in neutrophil trafficking and myocardial injury. The scarcity of carefully controlled, randomized trials precludes firm conclusions regarding the extent to which these biological changes translate into meaningful improvements in clinical outcomes. The problem is further complicated by the fact that the adverse effects of cardiopulmonary bypass largely depend on a genetically controlled balance between proinflammatory and antiinflammatory mediators. Currently, it is still impossible to predict, in a given patient, the side toward which this balance will be shifted. Nevertheless, accumulating experience identifies patient subgroups who may greatly benefit from avoiding extracorporeal circulation. These subsets include patients with severe extracardiac comorbidities (in particular, renal failure) and, possibly, patients with advanced left ventricular dysfunction, who may poorly tolerate superimposed, bypass-related, inflammatory tissue injuries.