Modified low density lipoprotein and lipoprotein-containing circulating immune complexes as diagnostic and prognostic biomarkers of atherosclerosis and type 1 diabetes macrovascular disease

Atherosclerosis originating from childhood: Specific features

Atherosclerosis is extremely widespread. Traditionally, it is considered a disease of older people, who most often experience problems with the heart and blood vessels. While much attention from the scientific community has been paid to studying the association between aging and atherosclerosis, as well as its consequences, there is evidence that atherosclerosis occurs at an early age. Atherosclerosis may form both during intrauterine development and in childhood. Nutrition plays an important role in childhood atherosclerosis, along with previous infectious diseases and excess weight of both the child and the mother. In the present review, we examined the development of atherosclerosis and the prerequisites in childhood.

Elevated small dense low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio is associated with an increased risk of metabolic dysfunction associated fatty liver disease in Chinese patients with type 2 diabetes mellitus

INTRODUCTION

It is demonstrated that elevated small dense low-density lipoprotein cholesterol (sdLDL-C), and reduced high-density lipoprotein cholesterol (HDL-C) is associated with Metabolic dysfunction-associated fatty liver disease (MAFLD). This study aims to explore the relationship between sdLDL-C to HDL-C ratio (SHR) and MAFLD in Chinese patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

A cross-sectional study was performed among 1904 patients with T2DM. Weighted multivariable logistic regression analysis was conducted to explore the relationship between the SHR and the risk of MAFLD. In addition, this study used a two-part linear regression model to identify threshold effects. Subgroup analysis, interaction tests and receiver operating characteristic (ROC) curve analysis were also carried out.

RESULTS

The overall MAFLD prevalence reached 48.1%. Multiple logistic regression analysis showed that SHR was positively correlated with the risk of MAFLD (OR = 2.37, 95% CI = 1.80-3.12). Subgroup analysis stratified by age, gender, hypertension and BMI showed that there was a consistent positive correlation. A non-linear relationship and saturation effect between SHR and MAFLD risk were identified, with an inverted L shaped curve and an inflection point at 1.02. The area under the curve (AUC) for SHR in the ROC analysis was significantly greater than sdLDL-C and HDL-C, with a sensitivity of 71.2% and a specificity of 62.1%.

CONCLUSIONS

Elevated levels of SHR is independently associated with an increased risk of MAFLD in patients with T2DM. SHR may be taken as practical indicators to assess the risk of MAFLD in T2DM patients.

Serum Malondialdehyde-Modified Low-Density Lipoprotein as a Risk Marker for Peripheral Arterial Stiffness in Maintenance Hemodialysis Patients

Background and Objectives: Peripheral arterial stiffness (PAS), assessed by brachial-ankle pulse wave velocity (baPWV), is an independent biomarker of cardiovascular diseases (CVD) in patients on maintenance hemodialysis (HD). Malondialdehyde-modified low-density lipoprotein (MDA-LDL), an oxidative stress marker, has been linked to atherosclerosis and CVD. However, the association between serum MDA-LDL and PAS among HD patients has not been fully elucidated. This study aimed to examine the association of serum MDA-LDL with PAS in HD patients and to identify the optimal cutoff value of serum MDA-LDL for predicting PAS. Materials and Methods: A cross-sectional study was conducted in 100 HD patients. Serum MDA-LDL was quantified using an enzyme-linked immunosorbent assay (ELISA), and baPWV was measured using a volume plethysmographic device. Patients were divided into the PAS group (baPWV > 18.0 m/s) and the non-PAS group (baPWV ≤ 18.0 m/s). The associations of baPWV and other clinical and biochemical parameters with serum MDA-LDL were assessed by multivariable logistic regression analyses. A receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cutoff value of serum MDA-LDL for predicting PAS. Results: In multivariable logistic regression analysis, higher serum MDA-LDL, older age, and higher serum C-reactive protein [odds ratios (ORs) and 95% confidence intervals: 1.014 (1.004-1.025), 1.044 (1.004-1.085) and 3.697 (1.149-11.893)] were significantly associated with PAS. In the ROC curve analysis, the optimal cutoff value of MDA-LDL for predicting PAS was 80.91 mg/dL, with a sensitivity of 79.25% and a specificity of 59.57%. Conclusions: Greater serum MDA-LDL levels, particularly ≥80.91 mg/dL, were independently associated with PAS in HD patients. The findings suggest that oxidative stress plays a crucial role in the pathogenesis of PAS, and targeting MDA-LDL may be a potential therapeutic strategy for reducing cardiovascular risk in HD patients.

Molecular Assessment of Methylglyoxal-Induced Toxicity and Therapeutic Approaches in Various Diseases: Exploring the Interplay with the Glyoxalase System

This comprehensive exploration delves into the intricate interplay of methylglyoxal (MG) and glyoxalase 1 (GLO I) in various physiological and pathological contexts. The linchpin of the narrative revolves around the role of these small molecules in age-related issues, diabetes, obesity, cardiovascular diseases, and neurodegenerative disorders. Methylglyoxal, a reactive dicarbonyl metabolite, takes center stage, becoming a principal player in the development of AGEs and contributing to cell and tissue dysfunction. The dual facets of GLO I-activation and inhibition-unfold as potential therapeutic avenues. Activators, spanning synthetic drugs like candesartan to natural compounds like polyphenols and isothiocyanates, aim to restore GLO I function. These molecular enhancers showcase promising outcomes in conditions such as diabetic retinopathy, kidney disease, and beyond. On the contrary, GLO I inhibitors emerge as crucial players in cancer treatment, offering new possibilities in diseases associated with inflammation and multidrug resistance. The symphony of small molecules, from GLO I activators to inhibitors, presents a nuanced understanding of MG regulation. From natural compounds to synthetic drugs, each element contributes to a molecular orchestra, promising novel interventions and personalized approaches in the pursuit of health and wellbeing. The abstract concludes with an emphasis on the necessity of rigorous clinical trials to validate these findings and acknowledges the importance of individual variability in the complex landscape of health.

Analysis of immunogenic cell death in atherosclerosis based on scRNA-seq and bulk RNA-seq data

BACKGROUND

Regulated cell death plays a very important role in atherosclerosis (AS). Despite a large number of studies, there is a lack of literature on immunogenic cell death (ICD) in AS.

METHOD

Carotid atherosclerotic plaque single-cell RNA (scRNA) sequencing data were analyzed to define involved cells and determine their transcriptomic characteristics. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, CIBERSORT, ESTIMATE and ssGSEA (Gene Set Enrichment Analysis), consensus clustering analysis, random forest (RF), Decision Curve Analysis (DCA), and the Drug-Gene Interaction and DrugBank databases were applied for bulk sequencing data. All data were downloaded from Gene Expression Omnibus (GEO).

RESULT

mDCs and CTLs correlated obviously with AS occurrence and development (k2(mDCs) = 48.333, P < 0.001; k2(CTL) = 130.56, P < 0.001). In total, 21 differentially expressed genes were obtained for the bulk transcriptome; KEGG enrichment analysis results were similar to those for differentially expressed genes in endothelial cells. Eleven genes with a gene importance score > 1.5 were obtained in the training set and validated in the test set, resulting in 8 differentially expressed genes for ICD. A model to predict occurrence of AS and 56 drugs that may be used to treat AS were obtained with these 8 genes.

CONCLUSION

Immunogenic cell death occurs mainly in endothelial cells in AS. ICD maintains chronic inflammation in AS and plays a crucial role in its occurrence and development. ICD related genes may become drug-targeted genes for AS treatment.

Glycation of LDL: AGEs, impact on lipoprotein function, and involvement in atherosclerosis

Atherosclerosis is a complex disease, and there are many factors that influence its development and the course of the disease. A deep understanding of the pathological mechanisms underlying atherogenesis is needed to develop optimal therapeutic strategies and treatments. In this review, we have focused on low density lipoproteins. According to multiple studies, their atherogenic properties are associated with multiple modifications of lipid particles. One of these modifications is Glycation. We considered aspects related to the formation of modified particles, as well as the influence of modification on their functioning. We paid special attention to atherogenicity and the role of glycated low-density lipoprotein (LDL) in atherosclerosis.

Human Neuraminidases: Structures and Stereoselective Inhibitors

This Perspective describes the classification, structures, substrates, mechanisms of action, and implications of human neuraminidases (hNEUs) in various pathologies. Some inhibitors have been developed for each isoform, leading to more precise interactions with hNEUs. Although crystal structure data are available for NEU2, most of the findings are based on NEU1 inhibition, and limited information is available for other hNEUs. Therefore, the synthesis of new compounds would facilitate the enrichment of the arsenal of inhibitors to better understand the roles of hNEUs and their mechanisms of action. Nevertheless, due to the already known inhibitors of human neuraminidase enzymes, a structure-activity relationship is presented along with different approaches to inhibit these enzymes for the development of potent and selective inhibitors. Among the different emerging strategies, one is the inhibition of the dimerization of NEU1 or NEU3, and the second is the inhibition of certain receptors located close to hNEU.

Lipoprotein sialylation in atherosclerosis: Lessons from mice

Sialylation is a dynamically regulated modification, which commonly occurs at the terminal of glycan chains in glycoproteins and glycolipids in eukaryotic cells. Sialylation plays a key role in a wide array of biological processes through the regulation of protein-protein interactions, intracellular localization, vesicular trafficking, and signal transduction. A majority of the proteins involved in lipoprotein metabolism and atherogenesis, such as apolipoproteins and lipoprotein receptors, are sialylated in their glycan structures. Earlier studies in humans and in preclinical models found a positive correlation between low sialylation of lipoproteins and atherosclerosis. More recent works using loss- and gain-of-function approaches in mice have revealed molecular and cellular mechanisms by which protein sialylation modulates causally the process of atherosclerosis. The purpose of this concise review is to summarize these findings in mouse models and to provide mechanistic insights into lipoprotein sialylation and atherosclerosis.

Increased nitro-oxidative toxicity in association with metabolic syndrome, atherogenicity and insulin resistance in patients with affective disorders

BACKGROUND

There is a strong comorbidity between mood disorders and metabolic syndrome (MetS). Increased levels of reactive oxygen and nitrogen species (RONS) and nitro-oxidative stress toxicity (NOSTOX) partially underpin this comorbidity.

AIMS

To examine the associations of RONS/NOSTOX biomarkers with MetS after adjusting for the significant effects of mood disorders (major depression, and bipolar type 1 and 2), generalized anxiety disorder (GAD), tobacco use disorder (TUD), and male sex.

METHODS

The study included subjects with (n=65) and without (n=107) MetS and measured levels of superoxide dismutase 1 (SOD1), lipid hydroperoxides (LOOH), nitric oxide metabolites (NOx), malondialdehyde (MDA), and advanced oxidation protein products (AOPP) and computed z unit-weighted composite scores which reflect RONS/NOSTOX. The study included 105 patients with mood disorders, 46 with GAD, and 95 with TUD.

RESULTS

MetS was associated with increased levels of MDA and AOPP, independently from mood disorders, TUD, sex and GAD. Atherogenicity and insulin resistance (IR) were significantly associated with a NOSTOX composite score. Mood disorders, TUD, GAD, male sex and MetS independently contribute to increased RONS/NOSTOX. The RONS/NOSTOX profile of MetS was different from that of GAD, which showed increased SOD1 and NOx levels. TUD was accompanied by increased SOD1, LOOH and MDA, and male sex by increased LOOH and AOPP.

CONCLUSIONS

MetS is characterized by increased lipid peroxidation with aldehyde formation and chlorinative stress, and atherogenicity and IR are strongly mediated by RONS/NOSTOX. Partially shared RONS/NOSTOX pathways underpin the comorbidity of MetS with mood disorders, GAD, and TUD.

Glycosylation and Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide, accounting for approximately 18 million deaths in 2017. Coronary artery disease is the predominant cause of death from CVD, followed by stroke. Owing to recent technological advancements, glycans and glycosylation patterns of proteins have been investigated in association with CVD risk factors and clinical events. These studies have found significant associations of glycans as biomarkers of systemic inflammation and major CVD risk factors and events. While more limited, studies have also shown that glycans may be useful for monitoring response to anti-inflammatory therapies and may be responsive to changes in lifestyle, particularly in patients with chronic inflammatory diseases. Glycans capture summative risk information related to inflammatory, immune, and signaling pathways and are promising biomarkers for CVD risk prediction and therapeutic monitoring.

Diabetic dyslipidaemia

Diabetes mellitus (DM) is an escalating pandemic and an established cardiovascular risk factor. An important aspect of the interaction between DM and atherosclerotic cardiovascular disease (ASCVD) is diabetic dyslipidaemia, an atherogenic dyslipidaemia encompassing quantitative [hypertriglyceridaemia (hyperTG) and decreased high density lipoprotein cholesterol (HDL)] and qualitative [increased small dense low density lipoprotein cholesterol (sdLDL) particles, large very low density lipoprotein cholesterol (VLDL) subfraction (VLDL1) and dysfunctional HDL] modifications in lipoproteins. Much of the pathophysiology linking DM and dyslipidaemia has been elucidated. This paper aims to review the pathophysiology and management of diabetic dyslipidaemia with respect to ASCVD. Briefly, the influence of diabetic kidney disease on lipid profile and lipid changes causing type 2 diabetes mellitus are highlighted. Biomarkers of diabetic dyslipidaemia, including novel markers and clinical trials that have demonstrated that non-lipid and lipid lowering therapies can lower cardiovascular risk in diabetics are discussed. The stands of various international guidelines on lipid management in DM are emphasised. It is important to understand the underlying mechanisms of diabetic dyslipidaemia in order to develop new therapeutic strategies against dyslipidaemia and diabetes. The various international guidelines on lipid management can be used to tailor a holistic approach specific to each patient with diabetic dyslipidaemia.

Dyslipidaemia in Type 1 Diabetes: Molecular Mechanisms and Therapeutic Opportunities

Cardiovascular disease (CVD) is the leading cause of death in Type 1 Diabetes (T1D). The molecular basis for atherosclerosis in T1D is heavily influenced by hyperglycaemia and its atherogenic effects on LDL. Ongoing research into the distinct pathophysiology of atherosclerosis in T1D offers exciting opportunities for novel approaches to calculate CVD risk in patients with T1D and to manage this risk appropriately. Currently, despite the increased risk of CVD in the T1D population, there are few tools available for estimating the risk of CVD in younger patients. This poses significant challenges for clinicians in selecting which patients might benefit from lipid-lowering therapies over the long term. The current best practice guidance for the management of dyslipidaemia in T1D is generally based on evidence from patients with T2D and the opinion of experts in the field. In this review article, we explore the unique pathophysiology of atherosclerosis in T1D, with a specific focus on hyperglycaemia-induced damage and atherogenic LDL modifications. We also discuss the current clinical situation of managing these patients across paediatric and adult populations, focusing on the difficulties posed by a lack of strong evidence and various barriers to treatment.

Anti-Inflammatory Therapy for Atherosclerosis: Focusing on Cytokines

Atherosclerosis is a well-known global health problem. Despite the high prevalence of the disease, numerous aspects of pathogenesis remain unclear. Subsequently, there are still no cure or adequate preventive measures available. Atherogenesis is now considered a complex interplay between lipid metabolism alterations, oxidative stress, and inflammation. Inflammation in atherogenesis involves cellular elements of both innate (such as macrophages and monocytes) and adaptive immunity (such as B-cells and T-cells), as well as various cytokines cascades. Because inflammation is, in general, a well-investigated therapeutic target, and strategies for controlling inflammation have been successfully used to combat a number of other diseases, inflammation seems to be the preferred target for the treatment of atherosclerosis as well. In this review, we summarized data on targeting the most studied inflammatory molecular targets, CRP, IL-1β, IL-6, IFN-γ, and TNF-α. Studies in animal models have shown the efficacy of anti-inflammatory therapy, while clinical studies revealed the incompetence of existing data, which blocks the development of an effective atheroprotective drug. However, all data on cytokine targeting give evidence that anti-inflammatory therapy can be a part of a complex treatment.

The lipid paradox in neuroprogressive disorders: Causes and consequences

Chronic systemic inflammation is associated with an increased risk of cardiovascular disease in an environment of low low-density lipoprotein (LDL) and low total cholesterol and with the pathophysiology of neuroprogressive disorders. The causes and consequences of this lipid paradox are explored. Circulating activated neutrophils can release inflammatory molecules such as myeloperoxidase and the pro-inflammatory cytokines interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha. Since activated neutrophils are associated with atherosclerosis and cardiovascular disease and with major depressive disorder, bipolar disorder and schizophrenia, it seems reasonable to hypothesise that the inflammatory molecules released by them may act as mediators of the link between systemic inflammation and the development of atherosclerosis in neuroprogressive disorders. This hypothesis is tested by considering the association at a molecular level of systemic inflammation with increased LDL oxidation; increased small dense LDL levels; increased lipoprotein (a) concentration; secretory phospholipase A₂ activation; cytosolic phospholipase A₂ activation; increased platelet activation; decreased apolipoprotein A1 levels and function; decreased paroxonase-1 activity; hyperhomocysteinaemia; and metabolic endotoxaemia. These molecular mechanisms suggest potential therapeutic targets.

Proatherogenic Sialidases and Desialylated Lipoproteins: 35 Years of Research and Current State from Bench to Bedside

This review summarizes the main achievements in basic and clinical research of atherosclerosis. Focusing on desialylation as the first and the most important reaction of proatherogenic pathological cascade, we speak of how desialylation increases the atherogenic properties of low density lipoproteins and decreases the anti-atherogenic properties of high density lipoproteins. The separate sections of this paper are devoted to immunogenicity of lipoproteins, the enzymes contributing to their desialylation and animal models of atherosclerosis. In addition, we evaluate the available experimental and diagnostic protocols that can be used to develop new therapeutic approaches for atherosclerosis.

The long and winding road to target protein misfolding in cardiovascular diseases

BACKGROUND

In the last decades, cardiovascular diseases (CVD) have remained the first leading cause of mortality and morbidity in the world. Although several therapeutic approaches have been introduced in the past, the development of novel treatments remains an important research goal, which is hampered by the lack of understanding of key mechanisms and targets. Emerging evidences in recent years indicate the involvement of misfolded proteins aggregation and the derailment of protein quality control in the pathogenesis of cardiovascular diseases. Several potential interventions targeting protein quality control have been translated from the bench to the bedside to effectively employ the misfolded proteins as promising therapeutic targets for cardiac diseases, but with trivial results.

DESIGN

In this review, we describe the recent progresses in preclinical and clinical studies of protein misfolding and compromised protein quality control by selecting and reporting studies focusing on cardiovascular diseases including cardiomyopathies, cardiac amyloidosis, atherosclerosis, atrial fibrillation and thrombosis.

RESULTS

In preclinical models, modulators of several molecular targets (eg heat shock proteins, unfolded protein response, ubiquitin protein system, autophagy and histone deacetylases) have been tested in various conditions with promising results although lacking an adequate transition towards clinical setting.

CONCLUSIONS

At present, no therapeutic strategies have been reported to attenuate proteotoxicity in patients with CVD due to a lack of specific biomarkers for pinpointing upstream events in protein folding defects at a subclinical stage of the diseases requiring an intensive collaboration between basic scientists and clinicians.

Mutations of mtDNA in some Vascular and Metabolic Diseases

BACKGROUND

The present review article considers some chronic diseases of vascular and metabolic genesis, the causes of which may be mitochondrial dysfunction. Very often, in the long course of the disease, complications may occur, leading to myocardial infarction or ischemic stroke and, as a result, death. In particular, a large percentage of human deaths nowadays belongs to cardiovascular diseases, such as coronary heart disease (CHD), arterial hypertension, cardiomyopathies, and type 2 diabetes mellitus.

OBJECTIVE

The aim of the present review was the analysis of literature sources, devoted to an investigation of a link of mitochondrial DNA mutations with chronic diseases of vascular and metabolic genesis.

RESULTS

The analysis of literature indicates the association of the mitochondrial genome mutations with coronary heart disease, type 2 diabetes mellitus, hypertension, and various types of cardiomyopathies.

CONCLUSION

The detected mutations can be used to analyze the predisposition to chronic diseases of vascular and metabolic genesis. They can also be used to create molecular-cell models necessary to evaluate the effectiveness of drugs developed for the treatment of these pathologies. MtDNA mutations associated with the absence of diseases of vascular and metabolic genesis could be potential candidates for gene therapy of the said diseases.

Roles of Endovascular Calyx Related Enzymes in Endothelial Dysfunction and Diabetic Vascular Complications

In recent years, the number of diabetic patients has rapidly increased. Diabetic vascular complications seriously affect people’s quality of life. Studies found that endothelial dysfunction precedes the vascular complications of diabetes. Endothelial dysfunction is related to glycocalyx degradation on the surface of blood vessels. Heparanase (HPSE), matrix metalloproteinase (MMP), hyaluronidase (HYAL), hyaluronic acid synthase (HAS), and neuraminidase (NEU) are related to glycocalyx degradation. Therefore, we reviewed the relationship between endothelial dysfunction and the vascular complications of diabetes from the perspective of enzymes.

The Association between the Triglyceride to High-density Lipoprotein Cholesterol Ratio and Low-density Lipoprotein Subclasses

Objective The triglyceride (TG)/high-density lipoprotein cholesterol (HDL-C) ratio is related to insulin resistance (IR). However, information about whether or not the TG/HDL-C ratio is associated with low-density lipoprotein (LDL) subclasses in the Japanese population is limited. Methods In total, 1,068 Japanese subjects who underwent an annual health examination and who were not taking medications were recruited. The association between the TG/HDL-C ratio and LDL subclasses was investigated using correlation, multiple regression, and receiver operating characteristic analyses. Results A correlation analysis revealed that both malondialdehyde-modified low-density lipoprotein (MDA-LDL) and small dense low-density lipoprotein cholesterol (sdLDL-C) were positively associated with the TG/HDL-C ratio. Furthermore, a multiple linear regression analysis revealed that the TG/HDL-C ratio was positively associated with MDA-LDL and sdLDL-C in both men and women. The multiple logistic regression analysis also revealed that the TG/HDL-C ratio was positively associated with the upper tertile of MDA-LDL and sdLDL-C in men and women. The LDL-C levels increased with the increasing TG/HDL-C ratio. The MDA-LDL and sdLDL-C are known to be positively associated with LDL-C. However, within the same LDL-C range, both MDA-LDL and sdLDL-C levels increased with the TG/HDL-C ratio, except for MDA-LDL levels in the LDL-C <112 mg/dL group in women. These results further supported the notion that the TG/HDL-C ratio was positively associated with the MDA-LDL and sdLDL-C levels, especially in the higher LDL-C range, in both men and women. The optimal cut-off points of the TG/HDL-C ratio for the upper tertile of MDA-LDL and sdLDL-C were 1.85 and 2.03 in men and 0.88 and 1.30 in women, respectively. Conclusion The TG/HDL-C ratio is positively associated with MDA-LDL and sdLDL-C in Japanese subjects. The relationship was particularly notable in subjects with high LDL-C levels.

Sialidase Activity in Human Blood Serum Has a Distinct Seasonal Pattern: A Pilot Study

Desialylation—loss of terminal sialic acid residues from glycoconjugates catalyzed by sialidases—is involved in many human diseases and is considered a key molecular event of atherosclerosis onset. Desialylated low-density lipoproteins with atherogenic properties have been detected in human blood previously. However, there is currently no consensus on the origin of desialylation activity in the bloodstream. Here, we suggest viral intervention as a possible explanation. In order to address our hypothesis, we studied seasonal patterns of blood serum sialidase enzymatic activity and designed an approach to detect and quantify viral sialidase genetic presence. Increased sialidase activity in autumn-winter combined with detectable levels of influenza virus sialidase mRNA suggests exogenous viral sialidase as a viable component of desialylation in human blood, providing new insights on the molecular background of atherogenesis.

Polychlorinated Biphenyl Quinone Promotes Atherosclerosis through Lipid Accumulation and Endoplasmic Reticulum Stress via CD36

Polychlorinated biphenyls (PCBs) are persistent organic environmental pollutants. According to previous epidemiological reports, PCBs exposure is highly related to atherosclerosis. However, studies of PCBs metabolites and atherosclerosis and corresponding mechanism studies are scarce. In this study, we evaluated the effect of 2,3,5-trichloro-6-phenyl-[1,4]-benzoquinone (PCB29-pQ), a presumptive PCB metabolite, on atherosclerosis. Aortic plaques were increased in PCB29-pQ-treated ApoE^-/- mice [intraperitoneally (i.p.) injection of 5 mg/kg body weight of PCB29-pQ once a week for 12 continuous weeks, high-fat feeding]. We observed lipids accumulation and the release of interleukin-1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), and interleukin-6 (IL-6) in ApoE^-/- mice. In addition, we found that PCB29-pQ promoted the levels of total cholesterol, free cholesterol, triglyceride, and cholesteryl ester. Mechanism investigation indicated that PCB29-pQ induces the activation of three branches of endoplasmic reticulum (ER) stress response, that is, phosphorylated protein kinase R-like ER kinase (p-PERK), eukaryotic translation initiation factor 2α (eIF2α) and transcription factor 6 (ATF6), which is responsible for downstream necrosis. More importantly, we found the silence of CD36 is able to reverse PCB29-pQ-induced adverse effects completely. Overall, PCB29-pQ exposure resulted in lipid accumulation, ER stress response, apoptosis, and pro-inflammatory cytokines release via CD36, ultimately leading to atherosclerosis.

Risk Factors for Cardiovascular Disease (CVD) in Adults with Type 1 Diabetes: Findings from Prospective Real-life T1D Exchange Registry

CONTEXT

Cardiovascular disease (CVD) is a major cause of mortality in adults with type 1 diabetes.

OBJECTIVE

We prospectively evaluated CVD risk factors in a large, contemporary cohort of adults with type 1 diabetes living in the United States.

DESIGN

Observational study of CVD and CVD risk factors over a median of 5.3 years.

SETTING

The T1D Exchange clinic network.

PATIENTS

Adults (age ≥ 18 years) with type 1 diabetes and without known CVD diagnosed before or at enrollment.

MAIN OUTCOME MEASURE

Associations between CVD risk factors and incident CVD were assessed by multivariable logistic regression.

RESULTS

The study included 8,727 participants (53% female, 88% non-Hispanic white, median age 33 years [interquartile ratio {IQR} = 21, 48], type 1 diabetes duration 16 years [IQR = 9, 26]). At enrollment, median HbA1c was 7.6% (66 mmol/mol) (IQR = 6.9 [52], 8.6 [70]), 33% used a statin, and 37% used blood pressure medication. Over a mean follow-up of 4.6 years, 325 (3.7%) participants developed incident CVD. Ischemic heart disease was the most common CVD event. Increasing age, body mass index, HbA1c, presence of hypertension and dyslipidemia, increasing duration of diabetes, and diabetic nephropathy were associated with increased risk for CVD. There were no significant gender differences in CVD risk.

CONCLUSION

HbA1c, hypertension, dyslipidemia and diabetic nephropathy are important risk factors for CVD in adults with type 1 diabetes. A longer follow-up is likely required to assess the impact of other traditional CVD risk factors on incident CVD in the current era.

Immune Complexes and the Risk of CVD in Type 1 Diabetes

We investigated whether the composition of modified forms of LDL in circulating immune complexes (LDL-ICs) was associated with cardiovascular disease (CVD) outcomes, including any CVD, major adverse cardiac and cerebrovascular events (MACCE), myocardial infarction (MI), and coronary artery disease, in type 1 diabetes (T1D). Our results demonstrate that the baseline levels of oxidized LDL (oxLDL), MDA-modified LDL (MDA-LDL), and advanced glycosylation-modified LDL (AGE-LDL) in circulating ICs were associated with the four CVD outcomes in unadjusted models, and adjustment by age and mean HbA_1c only resulted in minimal reduction of these associations. After adjustments were made for other cardiovascular risk factors, particularly LDL cholesterol, oxLDL-IC and MDA-LDL-IC remained independently associated with the risk of CVD, and oxLDL-IC was independently associated with the risk of MACCE and MI. In the majority of cases, the baseline levels of modified LDL-IC (measured many years before the occurrence of any CVD event) were associated with the risk of CVD over a 25-year period even after adjustment for other risk factors (including LDL cholesterol). Therefore, modified LDL biomarkers may help identify patients with T1D at high risk for MACCE and CVD events very early in the evolution of the disease, before other signals of disease are apparent.

The Atherogenic Role of Circulating Modified Lipids in Atherosclerosis

Lipid accumulation in the arterial wall is a crucial event in the development of atherosclerotic lesions. Circulating low-density lipoprotein (LDL) is the major source of lipids that accumulate in the atherosclerotic plaques. It was discovered that not all LDL is atherogenic. In the blood plasma of atherosclerotic patients, LDL particles are the subject of multiple enzymatic and non-enzymatic modifications that determine their atherogenicity. Desialylation is the primary and the most important atherogenic LDL modification followed by a cascade of other modifications that also increase blood atherogenicity. The enzyme trans-sialidase is responsible for the desialylation of LDL, therefore, its activity plays an important role in atherosclerosis development. Moreover, circulating modified LDL is associated with immune complexes that also have a strong atherogenic potential. Moreover, it was shown that antibodies to modified LDL are also atherogenic. The properties of modified LDL were described, and the strong evidence indicating that it is capable of inducing intracellular accumulation of lipids was presented. The accumulated evidence indicated that the molecular properties of modified LDL, including LDL-containing immune complexes can serve as the prognostic/diagnostic biomarkers and molecular targets for the development of anti-atherosclerotic drugs.

Modified and Dysfunctional Lipoproteins in Atherosclerosis: Effectors or Biomarkers?

Atherosclerotic diseases are the leading cause of mortality in industrialized countries. Correspondingly, studying the pathogenesis of atherosclerosis and developing new methods for its diagnostic and treatment remain in the focus of current medicine and health care. This review aims to discuss the mechanistic role of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) in atherogenesis. In particular, the generally accepted hypothesis about the key role of oxidized LDL in atherogenesis is questioned, and an alternative concept of multiple modification of LDL is presented. The fundamental question discussed in this review is whether LDL and HDL are effectors or biomarkers, or both. This is important for understanding whether lipoproteins are a therapeutic target or just diagnostic indicators.

Pathways of smooth muscle foam cell formation in atherosclerosis

PURPOSE OF REVIEW

Smooth muscle cells (SMCs) are the major cell type in human atherosclerosis-prone arteries and take up excess lipids, thereby contributing to luminal occlusion. Here we provide a focused review on pathways by which smooth muscle cells (SMCs) can become foam cells in atherosclerosis.

RECENT FINDINGS

A synthesis of recent and older investigations provides key mechanistic insights into SMC foam cell formation. LDL and other apoB-containing lipoproteins are modified by a diverse array of oxidative, enzymatic, and nonenzymatic processes present in the arterial intima. These modifications of LDL all promote the aggregation of LDL (agLDL), a key finding from analysis of arterial lesion particles. Scavenger receptor and phagocytic capacity of SMCs can vary greatly, perhaps related to differences in SMC phenotype or in-vitro cell culture environments, and can be increased with exposure to cytokines, growth factors, and cholesterol. Macrophages promote the formation of SMC foam cells in direct or indirect co-culture models.

SUMMARY

SMCs contribute significantly to the foam cell population in atherosclerosis. Further investigation and identification of key mechanisms of SMC foam cell formation will help drive new therapeutics to reduce cardiovascular disease.

Glycosylation of human plasma lipoproteins reveals a high level of diversity, which directly impacts their functional properties

AIMS

Human plasma lipoproteins are known to contain various glycan structures whose composition and functional importance are starting to be recognized. We assessed N-glycosylation of human plasma HDL and LDL and the role of their glycomes in cellular cholesterol metabolism.

METHODS

N-glycomic profiles of native and neuraminidase-treated HDL and LDL were obtained using HILIC-UHPLC-FLD. Relative abundance of the individual chromatographic peaks was quantitatively expressed as a percentage of total integrated area and N-glycan structures present in each peak were elucidated by MALDI-TOF MS. The capacity of HDL to mediate cellular efflux of cholesterol and the capacity of LDL to induce cellular accumulation of cholesteryl esters were evaluated in THP-1 cells.

RESULTS

HILIC-UHPLC-FLD analysis of HDL and LDL N-glycans released by PNGase F resulted in 22 and 18 distinct chromatographic peaks, respectively. The majority of N-glycans present in HDL (~70%) and LDL (~60%) were sialylated with one or two sialic acid residues. The most abundant N-glycan structure in both HDL and LDL was a complex type biantennary N-glycan with one sialic acid (A2G2S1). Relative abundances of several N-glycan structures were dramatically altered by the neuraminidase treatment, which selectively removed sialic acid residues. Native HDL displayed significantly greater efficacy in removing cellular cholesterol from THP-1 cells as compared to desialylated HDL (p < 0.05). Cellular accumulation of cholesteryl esters in THP-1 cells was significantly higher after incubations with desialylated LDL particles as compared to native LDL (p < 0.05).

CONCLUSIONS

N-glycome of human plasma lipoproteins reveals a high level of diversity, which directly impacts functional properties of the lipoproteins.

Novel Approaches to Anti-atherosclerotic Therapy: Cell-based Models and Herbal Preparations (Review of Our Own Data)

Atherosclerosis is a chronic arterial disease characterized by vascular inflammation, accumulation of lipids in the arterial wall, and formation and growth of atherosclerotic plaques followed by ischemia. In subclinical atherosclerosis, cholesterol retention in subendothelial cells leads to induction of local inflammation, generation of foam cells and lesion formation, followed by a chain of other pathogenic events. Atherosclerotic progression can frequently be fatal, since plaque rupture may lead to thrombosis and acute events, such as myocardial infarction, stroke and sudden death. Traditional anti-atherosclerotic therapy is mainly focused on improving the blood lipid profile and does not target various stages of plaque progression. Obviously, treating the disease at initial stages is better than beginning treatment at advanced stages and, in that regard, current atherosclerosis management can be improved. Cholesterol retention is an important component of atherogenesis that precedes plaque formation. Therapeutic targeting of cholesterol retention may be beneficial for preventing further atherogenic progression. For this purpose, we suggest using herbal preparations due to good tolerability and suitability for long-lasting treatment. We developed test systems based on cultured human intimal aortic cells for rapid screening of potential anti-atherogenic drugs. With the help of these test systems, we selected several natural substances with significant anti-atherogenic activity and further use these compounds to prepare herbal preparations for anti-atherosclerotic therapy. These preparations were clinically tested and showed good safety and a potent anti-atherogenic potential.

Association between the MGAT1 rs634501 polymorphism and serum lipid traits in the Chinese Han and Maonan ethnic groups

Little is known about the association of monoacylglycerol acyltransferase 1 gene (MGAT1) rs634501 single nucleotide polymorphism (SNP) and serum lipid profiles in the Chinese populations. The aim of this study was to detect the association of the MGAT1 rs634501 SNP and several environmental factors with serum lipid levels in the Chinese Maonan and Han populations. Genotypes of the SNP in 2014 unrelated participants (Han, 986; Maonan, 1028) were determined by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and confirmed by direct sequencing. The genotypic and allelic frequencies of the MGAT1 rs634501 SNP were significantly different between the Han and Maonan populations as well as between males and females in the Maonan population. The A allele carriers had lower serum apolipoprotein (Apo) A1 levels, the ApoA1/ApoB ratio and higher ApoB levels in Maonans; and lower high-density lipoprotein cholesterol, ApoA1 levels, ApoA1/ApoB ratio, and higher triglyceride levels in Han than the A allele non-carriers. There were also different associations of the MGAT1 rs634501 SNP and serum lipid profiles between males and females in the both ethnic groups. Serum lipid parameters in the two ethnic groups were also associated with several environmental factors. These results suggest that the association of the MGAT1 rs634501 SNP and serum lipid parameters might have ethnic- and/or sex-specificity.

Sialidase activity in human pathologies

Sialic acid residues are frequently located at the terminal positions of glycoconjugate chains of cellular glycocalyx. Sialidases, or neuraminidases, catalyse removal of these residues thereby modulating various normal and pathological cellular activities. Recent studies have revealed the involvement of sialidases in a wide range of human disorders, including neurodegenerative disorders, cancers, infectious diseases and cardiovascular diseases. The accumulating data make sialidases an interesting potential therapeutic target. Modulating the activity of these enzymes may have beneficial effects in several pathologies. Four types of mammalian sialidases have been described: NEU1, NEU2, NEU3 and NEU4. They are encoded by different genes and characterized by different subcellular localization. In this review, we will summarize the current knowledge on the roles of different sialidases in pathological conditions.

Immunogenic lipid markers of atherosclerosis in type 2 diabetic patients on program haemodialysis

Aim. Determination of desialized apolipoprotein-B-100 (apoB-100) and lipoprotein-containing circulating immune complexes in patients with chronic kidney disease (CKD) in program hemodialysis with type 2 diabetes mellitus. Materials and methods. We examined 81 patients with CKD (50 men / 31 women) treated with program hemodialysis, of which 36 (17/19) with type 2 diabetes mellitus, 45 (33/12) non-diabetic patients. The levels of total cholesterol, triglycerides and desialylated apoB-100 in blood plasma and lipoprotein-containing circulating immune complexes. A color duplex scan of brachiocephalic arteries was used to assess the extent of development of atherosclerosis with the determination of the thickness of the intima-medial complex. Results and discussion. Patients with diabetes had high values of total cholesterol, triglycerides (p

LDL and foam cell formation as the basis of atherogenesis

PURPOSE OF REVIEW

Lipoprotein-induced intracellular lipid accumulation (foam cell formation) is a trigger of atherogenesis at the subendothelial arterial cell level. The purpose of this review is to describe the recent data related to the possible mechanisms of LDL-induced formation of lipid-laden foam cells and their role in the onset and development of atherosclerotic lesion.

RECENT FINDINGS

The most interesting current studies are related to the factors affecting foam cell formation.

SUMMARY

The phenomenon of lipid accumulation in cultured cells became the basis for creating a cellular test system that has already been successfully applied for development of drugs possessing direct antiatherosclerotic activity, and then the efficacy of these drugs was demonstrated in clinical studies. Moreover, this test system could be used for diagnostic assessing lipoproteins atherogenicity.

Circulating low density lipoprotein (LDL)

Low-density lipoprotein (LDL) particles are known as atherogenic agents in coronary artery diseases. They modify to other electronegative forms and may be the subject for improvement of inflammatory events in vessel subendothelial spaces. The circulating LDL value is associated with the plasma PCSK-9 level. They internalize into macrophages using the lysosomal receptor-mediated pathways. LDL uptake is related to the membrane scavenger receptors, modifications of lipid and protein components of LDL particles, vesicular maturation and lipid stores of cells. Furthermore, LDL vesicular trafficking is involved with the function of some proteins such as Rab and Lamp families. These proteins also help in the transportation of free cholesterol from lysosome into the cytosol. The aggregation of lipids in the cytosol is a starting point for the formation of foam cells so that they may participate in the primary core of atherosclerosis plaques. The effects of macrophage subclasses are different in the formation and remodeling of plaques. This review is focused on the cellular and molecular events involved in cholesterol homeostasis.

Immunometabolic Regulation of Vascular Redox State: The Role of Adipose Tissue

SIGNIFICANCE

Vascular oxidative stress plays a crucial role in atherogenesis and cardiovascular disease (CVD). Recent evidence suggests that vascular redox state is under the control of complex pathophysiological mechanisms, ranging from inflammation to obesity and insulin resistance (IR). Recent Advances: Adipose tissue (AT) is now recognized as a dynamic endocrine and paracrine organ that secretes several bioactive molecules, called adipokines. AT has recently been shown to regulate vascular redox state in both an endocrine and a paracrine manner through the secretion of adipokines, therefore providing a mechanistic link for the association between obesity, IR, inflammation, and vascular disease. Importantly, AT behaves as a sensor of cardiovascular oxidative stress, modifying its secretory profile in response to cardiovascular oxidative injury.

CRITICAL ISSUES

The present article presents an up-to-date review of the association between AT and vascular oxidative stress. We focus on the effects of individual adipokines on modulating reactive oxygen species production and scavenging in the vascular wall. In addition, we highlight how inflammation, obesity, and IR alter the biology and secretome of AT leading to a more pro-oxidant phenotype with a particular focus on the local regulatory mechanisms of perivascular AT driven by vascular oxidation.

FUTURE DIRECTIONS

The complex and dynamic biology of AT, as well as its importance in the regulation of vascular redox state, provides numerous opportunities for the development of novel, targeted treatments in the management of CVD. Therapeutic modulation of AT biology could improve vascular redox state affecting vascular disease pathogenesis. Antioxid. Redox Signal. 29, 313-336.

Association of the LIPC rs1532085 SNP and serum lipid traits in the Chinese Maonan and Han populations

The hepatic lipase gene (LIPC) is known to play an important role in lipid and lipoprotein metabolism pathways, but the association of the LIPC rs1532085 single nucleotide polymorphism (SNP) and serum lipid profiles has not been previously reported in different racial/ethnic groups. The present study was to detect the association of the LIPC rs1532085 SNP and several environmental factors with serum lipid levels in the Maonan and Han populations. Genotypes of the LIPC rs1532085 SNP in 833 individuals of Maonan nationality and 801 participants of Han nationality were determined by polymerase chain reaction and restriction fragment length polymorphism. The frequencies of AA, AG, and GG genotypes were 22.34%, 47.70%, and 29.96% in Han, and 24.96%, 51.38%, and 23.64% in Maonan populations (P < 0.05). The frequency of the G allele was 53.80% in Han and 49.33% in Maonan individuals (P < 0.05). The G allele carriers had lower total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), Apolipoprotein (Apo) A1 and ApoB levels in Han than the G allele non-carriers, but not in Maonan. Subgroup analyses indicated that the G allele carriers had lower TC, TG, LDL-C and ApoA1 levels in Han females than the G allele non-carriers (P < 0.05-0.001). Serum lipid parameters in the two ethnic groups were also associated with several environmental factors. These findings revealed that there might be a racial/ethnic- and/or sex-specific association between the LIPC rs1532085 SNP and serum lipid parameters in some populations.

Calcifying Matrix Vesicles and Atherosclerosis

Artery calcification is a well-recognized predictor of late atherosclerotic complications. In the intima media, calcification starts with apoptosis of vascular smooth muscle cells (VSMCs) and the release of calcifying matrix vesicles with diameter of 0.5–15 μm that can be observed microscopically. In complicated plaques, calcification is generally less frequent. Calcifying vesicles are released by proatherosclerotic VSMCs into the collagen-rich matrix. The vesicles can penetrate into the intima media and protrude into the arterial lumen and thereby may represent a potential cause of atherothrombosis. In calcified fibrolipid plaques, the rate of calcification is increased but is followed with healing of a lesion rupture and exhibited by further erosion and/or intimal thickening. Generally, calcification directly correlates with the apoptosis of VSMCs and macrophages accompanied by the release of osteogenic matrix vesicles. This is a hallmark of atherosclerosis-related apoptosis of VSMCs that is commonly released in plaque stabilization.

New Insights into the Role of Inflammation in the Pathogenesis of Atherosclerosis

Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of lipids, smooth muscle cell proliferation, cell apoptosis, necrosis, fibrosis, and local inflammation. Immune and inflammatory responses have significant effects on every phase of atherosclerosis, and increasing evidence shows that immunity plays a more important role in atherosclerosis by tightly regulating its progression. Therefore, understanding the relationship between immune responses and the atherosclerotic microenvironment is extremely important. This article reviews existing knowledge regarding the pathogenesis of immune responses in the atherosclerotic microenvironment, and the immune mechanisms involved in atherosclerosis formation and activation.

The SRGAP2 SNPs, their haplotypes and G × E interactions on serum lipid traits

Maonan nationality is a relatively conservative and isolated minority in China. Little is known about the association of the Slit-Robo Rho GTPase activating protein 2 gene (SRGAP2) single nucleotide polymorphisms (SNPs) and serum lipid levels in the Chinese populations. This study was performed to clarify the association of the SRGAP2 rs2483058 and rs2580520 SNPs and their haplotypes with serum lipid traits in the Maonan and Han populations. Genotyping of the 2 SNPs was performed in 2444 unrelated subjects (Han, 1210 and Maonan, 1234) by polymerase chain reaction and restriction fragment length polymorphism combined with gel electrophoresis, and then confirmed by direct sequencing. The allelic (rs2483058) and genotypic (rs2483058 and rs2580520) frequencies were different between the two ethnic groups. Four haplotypes were identified in our populations, and the rs2483058G-rs2580520C haplotype was the commonest one. The rs2483058C-rs2580520G haplotype was associated with an increased risk of dyslipidemia, and showed consistent association with serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), apolipoprotein (Apo) A1 levels, and the ApoA1/ApoB ratio. These results indicated that the SRGAP2 SNPs and their haplotypes were associated with serum lipid levels. Their haplotypes can explain much more serum lipid variation than any single SNP alone, especially for serum TC, HDL-C and ApoA1 levels.

Decreased high density lipoprotein cholesterol is an independent predictor for persistent organ failure, pancreatic necrosis and mortality in acute pancreatitis

High density lipoprotein cholesterol (HDL-C) has been reported as a significant indicator of systemic inflammation. The association underlying HDL-C and persistent organ failure (POF), pancreatic necrosis (PNec) and mortality in acute pancreatitis (AP) has not been evaluated. From 2007 to 2016, consecutive AP patients with admission lipid profiles assessment were included in this study. The association of HDL-C value and other lipids with outcomes was explored with Cox proportional regression models, which were adjusted for confounding factors. 1131 consecutive AP patients were clinically eligible. Overall, 17.9% of the patients developed with POF, 27.1% experienced PNec, and 6.7% died during hospitalization. Lower HDL-C median (<1.06 mmol/L) was identified as an independent prognostic factor of the outcomes. Moreover, there was a positive trend for the association across increasing HDL-C quartiles and POF, PNec and mortality after multivariable analysis (p values were <0.001, <0.001 and 0.043, respectively). The AUC of HDL-C for the outcomes were comparable to that of Ranson score for diagnosing POF (0.778 vs. 0.678; P < 0.001), PNec (0.734 vs. 0.701; P = 0.143) and mortality (0.768 vs. 0.745; P = 0.516). Decreased HDL-C value is an independent risk factor for the incidence of POF, PNec and in-hospital mortality in AP.