Electronegative low-density lipoprotein increases the risk of ischemic lower-extremity peripheral artery disease in uremia patients on maintenance hemodialysis

The NLRP3 Inflammasome as a Pathogenic Player Showing Therapeutic Potential in Rheumatoid Arthritis and Its Comorbidities: A Narrative Review

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease characterized by chronic synovitis and the progressive destruction of cartilage and bone. RA is commonly accompanied by extra-articular comorbidities. The pathogenesis of RA and its comorbidities is complex and not completely elucidated. The assembly of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome activates caspase-1, which induces the maturation of interleukin (IL)-1β and IL-18 and leads to the cleavage of gasdermin D with promoting pyroptosis. Accumulative evidence indicates the pathogenic role of NLRP3 inflammasome signaling in RA and its comorbidities, including atherosclerotic cardiovascular disease, osteoporosis, and interstitial lung diseases. Although the available therapeutic agents are effective for RA treatment, their high cost and increased infection rate are causes for concern. Recent evidence revealed the components of the NLRP3 inflammasome as potential therapeutic targets in RA and its comorbidities. In this review, we searched the MEDLINE database using the PubMed interface and reviewed English-language literature on the NLRP3 inflammasome in RA and its comorbidities from 2000 to 2023. The current evidence reveals that the NLRP3 inflammasome contributes to the pathogenesis of RA and its comorbidities. Consequently, the components of the NLRP3 inflammasome signaling pathway represent promising therapeutic targets, and ongoing research might lead to the development of new, effective treatments for RA and its comorbidities.

The Oxidized Lipoproteins In Vivo: Its Diversity and Behavior in the Human Circulation

A high concentration of low-density lipoproteins (LDLs) in circulation has been well-known as a major risk factor for cardiovascular diseases. The presence of oxidized LDLs (oxLDLs) in atherosclerotic lesions and circulation was demonstrated using anti-oxLDL monoclonal antibodies. The so-called “oxLDL hypothesis”, as a mechanism for atherosclerosis development, has been attracting attention for decades. However, the oxLDL has been considered a hypothetical particle since the oxLDL present in vivo has not been fully characterized. Several chemically modified LDLs have been proposed to mimic oxLDLs. Some of the subfractions of LDL, especially Lp(a) and electronegative LDL, have been characterized as oxLDL candidates as oxidized phospholipids that stimulate vascular cells. Oxidized high-density lipoprotein (oxHDL) and oxLDL were discovered immunologically in vivo. Recently, an oxLDL-oxHDL complex was found in human plasma, suggesting the involvement of HDLs in the oxidative modification of lipoproteins in vivo. In this review, we summarize our understanding of oxidized lipoproteins and propose a novel standpoint to understand the oxidized lipoproteins present in vivo.

Mechanosensitive molecular interactions in atherogenic regions of the arteries: development of atherosclerosis

A terrible disease of the cardiovascular system, atherosclerosis, develops in the areas of bends and branches of arteries, where the direction and modulus of the blood flow velocity vector change, and consequently so does the mechanical effect on endothelial cells in contact with the blood flow. The review focuses on topical research studies on the development of atherosclerosis – mechanobiochemical events that transform the proatherogenic mechanical stimulus of blood flow – low and low/oscillatory arterial wall shear stress in the chains of biochemical reactions in endothelial cells, leading to the expression of specific proteins that cause the progression of the pathological process. The stages of atherogenesis, systemic risk factors for atherogenesis and its important hemodynamic factor, low and low/oscillatory wall shear stress exerted by blood flow on the endothelial cells lining the arterial walls, have been described. The interactions of cell adhesion molecules responsible for the development of atherosclerosis under low and low/oscillating shear stress conditions have been demonstrated. The activation of the regulator of the expression of cell adhesion molecules, the transcription factor NF-κB, and the factors regulating its activation under these conditions have been described. Mechanosensitive signaling pathways leading to the expression of NF-κB in endothelial cells have been described. Studies of the mechanobiochemical signaling pathways and interactions involved in the progression of atherosclerosis provide valuable information for the development of approaches that delay or block the development of this disease. Key words: atherogenesis; shear stress; transcription factor NF-κB; RelA expression; mechanosensitive receptors; cell adhesion molecules; signaling pathways; mechanotransduction.

Circulating Biomarkers Reflecting Destabilization Mechanisms of Coronary Artery Plaques: Are We Looking for the Impossible?

Despite significant strides to mitigate the complications of acute coronary syndrome (ACS), this clinical entity still represents a major global health burden. It has so far been well-established that most of the plaques leading to ACS are not a result of gradual narrowing of the vessel lumen, but rather a result of sudden disruption of vulnerable atherosclerotic plaques. As most of the developed imaging modalities for vulnerable plaque detection are invasive, multiple biomarkers were proposed to identify their presence. Owing to the pivotal role of lipids and inflammation in the pathophysiology of atherosclerosis, most of the biomarkers originated from one of those processes, whereas recent advancements in molecular sciences shed light on the use of microRNAs. Yet, at present there are no clinically implemented biomarkers or any other method for that matter that could non-invasively, yet reliably, diagnose the vulnerable plaque. Hence, in this review we summarized the available knowledge regarding the pathophysiology of plaque instability, the current evidence on potential biomarkers associated with plaque destabilization and finally, we discussed if search for biomarkers could one day bring us to non-invasive, cost-effective, yet valid way of diagnosing the vulnerable, rupture-prone coronary artery plaques.

Autoimmune Rheumatic Diseases: An Update on the Role of Atherogenic Electronegative LDL and Potential Therapeutic Strategies

Atherosclerosis has been linked with an increased risk of atherosclerotic cardiovascular disease (ASCVD). Autoimmune rheumatic diseases (AIRDs) are associated with accelerated atherosclerosis and ASCVD. However, the mechanisms underlying the high ASCVD burden in patients with AIRDs cannot be explained only by conventional risk factors despite disease-specific factors and chronic inflammation. Nevertheless, the normal levels of plasma low-density lipoprotein (LDL) cholesterol observed in most patients with AIRDs do not exclude the possibility of increased LDL atherogenicity. By using anion-exchange chromatography, human LDL can be divided into five increasingly electronegative subfractions, L1 to L5, or into electropositive and electronegative counterparts, LDL (+) and LDL (-). Electronegative L5 and LDL (-) have similar chemical compositions and can induce adverse inflammatory reactions in vascular cells. Notably, the percentage of L5 or LDL (-) in total LDL is increased in normolipidemic patients with AIRDs. Electronegative L5 and LDL (-) are not recognized by the normal LDL receptor but instead signal through the lectin-like oxidized LDL receptor 1 (LOX-1) to activate inflammasomes involving interleukin 1β (IL-1β). Here, we describe the detailed mechanisms of AIRD-related ASCVD mediated by L5 or LDL (-) and discuss the potential targeting of LOX-1 or IL-1β signaling as new therapeutic modalities for these diseases.

Effects of Lipids and Lipoproteins on Mesenchymal Stem Cells Used in Cardiac Tissue Regeneration

Mesenchymal stem cells (MSCs) have two characteristics of interest for this paper: the ability to self-renew, and the potential for multiple-lineage differentiation into various cells. MSCs have been used in cardiac tissue regeneration for over a decade. Adult cardiac tissue regeneration ability is quite low; it cannot repair itself after injury, as the heart cells are replaced by fibroblasts and lose function. It is therefore important to search for a feasible way to repair and restore heart function through stem cell therapy. Stem cells can differentiate and provide a source of progenitor cells for cardiomyocytes, endothelial cells, and supporting cells. Studies have shown that the concentrations of blood lipids and lipoproteins affect cardiovascular diseases, such as atherosclerosis, hypertension, and obesity. Furthermore, the MSC lipid profiles, such as the triglyceride and cholesterol content, have been revealed by lipidomics, as well as their correlation with MSC differentiation. Abnormal blood lipids can cause serious damage to internal organs, especially heart tissue. In the past decade, the accumulated literature has indicated that lipids/lipoproteins affect stem cell behavior and biological functions, including their multiple lineage capability, and in turn affect the outcome of regenerative medicine. This review will focus on the effect of lipids/lipoproteins on MSC cardiac regenerative medicine, as well as the effect of lipid-lowering drugs in promoting cardiomyogenesis-associated MSC differentiation.

Correlation between lower extremity arterial disease and skeletal muscle mass in patients with type 2 diabetes mellitus

Objectives

To evaluate skeletal muscle mass in patients with both type 2 diabetes mellitus (T2DM) and concomitant lower extremity arterial disease (LEAD) and determine the contribution of skeletal muscle mass to macrovascular diseases.

Methods

In total, 112 patients with T2DM were divided into the T2DM and T2DM + LEAD groups. Hepatic function, renal function, uric acid, blood glucose, and glycated hemoglobin (HbA1C) were measured. Dual-energy X-ray absorptiometry was used to measure visceral fat area and skeletal muscle mass index (SMI).

Results

Waist-to-hip ratio, uric acid, and body fat percentage were significantly higher in the T2DM+LEAD group than in the T2DM group; SMI was significantly lower in the T2DM+LEAD group than in the T2DM group. There were no significant differences in albumin, creatinine, fasting blood glucose, HbA1C, or blood lipids. Uric acid, SMI, and body fat percentage were significantly positively correlated with T2DM and concomitant LEAD. Logistic regression analyses suggested that SMI is an independent risk factor for LEAD in T2DM (odds ratio = 1.517; 95% confidence interval: 1.082–2.126).

Conclusions

Skeletal muscle mass is lower in patients with T2DM and concomitant LEAD than in patients with T2DM who do not exhibit LEAD. SMI is an important risk factor for LEAD.

Association between Negatively Charged Low-Density Lipoprotein L5 and Subclinical Atherosclerosis in Rheumatoid Arthritis Patients

L5, the most negatively charged subfraction of low-density lipoprotein (LDL), is implicated in atherogenesis. We examined the relationship between plasma L5 levels and the occurrence of subclinical atherosclerosis in patients with rheumatoid arthritis (RA). Using anion-exchange purification with fast-protein liquid chromatography, we determined the proportion of plasma L5 of LDL (L5%) in 64 RA patients and 12 healthy controls (HC). Plasma L5% and L5 levels were significantly higher in RA patients (median, 1.4% and 1.92 mg/dL) compared with HC (0.9%, p < 0.005; and 1.27 mg/dL, p < 0.05) and further increased in patients with subclinical atherosclerosis (2.0% and 2.88 mg/dL). L5% and L5 levels decreased in patients after 6-months of therapy (p < 0.01). Subclinical atherosclerosis was indicated by plaque and intima-media thickness determined by carotid ultrasonography. Using multivariate analysis, L5% and L5 levels are revealed as the predictors of subclinical atherosclerosis (odds ratio, 4.94 and 1.01; both p < 0.05). Receiver operating characteristic curves showed that cut-off values of L5% ≥ 1.45% and L5 levels ≥ 2.58 mg/dL could predict subclinical atherosclerosis in patients (both p < 0.001). Immunoblotting showed that the expression levels of lectin-like oxidized LDL receptor-1 (LOX-1) was increased in RA patients. Together, our findings suggest that plasma L5% and L5 levels may be predictors of cardiovascular risk in RA patients.