Opinion: On the Way towards the New Paradigm of Atherosclerosis

Targeting of AMPK/MTOR signaling in the management of atherosclerosis: Outmost leveraging

Atherosclerosis (AS) is a chronic vascular disorder that is characterized by the thickening and narrowing of arteries due to the development of atherosclerotic plaques. The traditional risk factors involved in AS are obesity, type 2 diabetes (T2D), dyslipidemia, hypertension, and smoking. Furthermore, non-traditional risk factors for AS, such as inflammation, sleep disturbances, physical inactivity, air pollution, and alterations of gut microbiota, gained attention in relation to the pathogenesis of AS. Interestingly, the pathogenesis of AS, is complex and related to different abnormalities of cellular and sub-cellular signaling pathways. It has been illustrated that AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (MTOR) pathways are involved in AS pathogenesis. Mounting evidence indicated that AMPK plays a critical role in attenuating the development of AS by activating autophagy, which is impaired during atherogenesis. AMPK has a vasculoprotective effect by reducing lipid accumulation, inflammatory cell proliferation, and the release of pro-inflammatory cytokines, as well as decreasing inflammatory cell adhesion to the vascular endothelium. AMPK activation by metformin inhibits the migration of vascular smooth muscle cells (VSMCs) and AS development. However, the MTOR pathway contributes to AS by inhibiting autophagy, highlighting autophagy as a crucial link between the AMPK and MTOR pathways in AS pathogenesis. The MTOR is a key inducer of endothelial dysfunction and is involved in the development of AS. Therefore, both the AMPK and MTOR pathways play a crucial role in the pathogenesis of AS. However, the exact role of AMPK and MTOR pathways in the pathogenesis of AS is not fully clarified. Therefore, this review aims to discuss the potential role of the AMPK/MTOR signaling pathway in AS, and how AMPK activators and MTOR inhibitors influence the development and progression of AS. In conclusion, AMPK activators and MTOR inhibitors have vasculoprotective effects against the development and progression of AS.

Atherosclerosis: A Comprehensive Review of Molecular Factors and Mechanisms

Atherosclerosis, a condition characterized by the accumulation of lipids and a culprit behind cardiovascular events, has long been studied. However, in recent years, there has been an increase in interest in its initiation, with researchers shifting focus from traditional pathways involving the vascular infiltration of oxidized lipids and towards the novel presence of chronic inflammatory pathways. The accumulation of pro-inflammatory cytokines, in combination with the activation of transcription factors, creates a positive feedback loop that drives the creation and progression of atherosclerosis. From the upregulation of the nod-like receptor protein 3 (NLRP3) inflammasome and the Notch and Wnt pathways to the increased expression of VEGF-A and the downregulation of connexins Cx32, Cx37, and Cx40, these processes contribute further to endothelial dysfunction and plaque formation. Herein, we aim to provide insight into the molecular pathways and mechanisms implicated in the initiation and progression of atherosclerotic plaques, and to review the risk factors associated with their development.

Stem cell-derived exosome delivery systems for treating atherosclerosis: The new frontier of stem cell therapy

Cardiovascular diseases (CVDs) are a leading cause of mortality worldwide. As a chronic inflammatory disease with a complicated pathophysiology marked by abnormal lipid metabolism and arterial plaque formation, atherosclerosis is a major contributor to CVDs and can induce abrupt cardiac events. The discovery of exosomes' role in intercellular communication has sparked a great deal of interest in them recently. Exosomes are involved in strategic phases of the onset and development of atherosclerosis because they have been identified to control pathophysiologic pathways including inflammation, angiogenesis, or senescence. This review investigates the potential role of stem cell-derived exosomes in atherosclerosis management. We briefly introduced atherosclerosis and stem cell therapy including stem cell-derived exosomes. The biogenesis of exosomes along with their secretion and isolation have been elaborated. The design engineering of exosomes has been summarized to present how drug loading and surface modification with targeting ligands can improve the therapeutic and targeting capacity of exosomes, demonstrating atheroprotective action. Moreover, the mechanism of action (endothelial dysfunction, reduction of dyslipidemia, macrophage polarization, vascular calcification, and angiogenesis) of drug-loaded exosomes to treat atherosclerosis has been discussed in detail. In the end, a comparative and balanced viewpoint has been given regarding the current challenges and potential solutions to advance exosome engineering for cardiovascular therapeutic applications.

Regeneration of Vascular Endothelium in Different Large Vessels

The regeneration of endothelial cells (ECs) lining arteries, veins, and large lymphatic vessels plays an important role in vascular pathology. To understand the mechanisms of atherogenesis, it is important to determine what happens during endothelial regeneration. A comparison of these processes in the above-mentioned vessels reveals both similarities and some significant differences. Regeneration is carried out by moving intact ECs from the edges of the viable endothelial layer towards the centre of the EC damage zone. A sharp decrease in contact inhibition leads to the spreading of the edges of the ECs situated on the damage border. This stimulates the second row of ECs to enter the S-phase, then the G2 phase of cell cycle, and finally mitosis. In all three types of vessels studied, mitotically dividing ECs were found using correlation light and electron microscopy. These ECs have a body protruding into the lumen of the vessel, covered with micro-villi and other outgrowths. The level of EC rounding and protruding is highest in the arteries and least pronounced in the lymphatic vessels. The intercellular contacts of mitotically dividing cells become wider. The EC division leads to an increase in the density of ECs. ECs moving over the damaged area and partially outside the damaged area acquire a fusiform shape. In the process of regeneration of arterial endothelium, the damaged ECs are removed. Then health ECs move to a surface devoid of endothelium, and detach spreading out, flattened platelets from the luminal surface of the vessel. In the veins, ECs grow on the surface of platelets and microthrombi. In lymphatic vessels, ECs detach from the basement membrane slower than in the veins and arteries. There, the migrating ECs grow under fibrin fibres. After some time (usually after 30 days), the EC mosaic returns to normal in all three types of vessels.

Glycosylation: mechanisms, biological functions and clinical implications

Protein post-translational modification (PTM) is a covalent process that occurs in proteins during or after translation through the addition or removal of one or more functional groups, and has a profound effect on protein function. Glycosylation is one of the most common PTMs, in which polysaccharides are transferred to specific amino acid residues in proteins by glycosyltransferases. A growing body of evidence suggests that glycosylation is essential for the unfolding of various functional activities in organisms, such as playing a key role in the regulation of protein function, cell adhesion and immune escape. Aberrant glycosylation is also closely associated with the development of various diseases. Abnormal glycosylation patterns are closely linked to the emergence of various health conditions, including cancer, inflammation, autoimmune disorders, and several other diseases. However, the underlying composition and structure of the glycosylated residues have not been determined. It is imperative to fully understand the internal structure and differential expression of glycosylation, and to incorporate advanced detection technologies to keep the knowledge advancing. Investigations on the clinical applications of glycosylation focused on sensitive and promising biomarkers, development of more effective small molecule targeted drugs and emerging vaccines. These studies provide a new area for novel therapeutic strategies based on glycosylation.

Prevalence and management of dyslipidemia in primary care practices in Canada

OBJECTIVE

To estimate the prevalence of dyslipidemia and to describe its management in Canadian primary care.

DESIGN

Retrospective cohort study using primary care electronic medical record data.

SETTING

Canada.

PARTICIPANTS

Adults aged 40 years or older who saw a Canadian Primary Care Sentinel Surveillance Network contributor between January 1, 2018, and December 31, 2019.

MAIN OUTCOME MEASURES

Presence or absence of dyslipidemia as identified by a validated case definition and the treatment status of patients identified as having dyslipidemia based on having been prescribed a lipid-lowering agent (LLA).

RESULTS

In total, 50.0% of the 773,081 patients 40 years of age or older who had had a primary care visit in 2018 or 2019 were identified as having dyslipidemia. Dyslipidemia was more prevalent in patients 65 or older (61.5%), in males (56.7%) versus females (44.7%), and in those living in urban areas (50.0%) versus rural areas (45.2%). In patients with documented dyslipidemia, 42.8% had evidence of treatment with an LLA. Stratifying patients by Framingham risk score revealed that those in the high-risk category were more likely to have been prescribed an LLA (65.0%) compared with those in the intermediate-risk group (48.7%) or the low-risk group (22.8%). The strongest determinants of receiving LLA treatment for dyslipidemia include sex, with males being 1.95 times more likely to have been treated compared with females (95% CI 1.91 to 1.98; P<.0001); and body mass index, with those with obesity having a significantly increased likelihood of being treated with an LLA (adjusted odds ratio of 1.36, 95% CI 1.32 to 1.41; P<.0001).

CONCLUSION

This study provides an updated look at the prevalence and treatment of dyslipidemia among Canadians. Half of patients aged 40 years or older have dyslipidemia, with an even higher prevalence observed among adults aged 65 years or older, males, and those with obesity or other chronic conditions. There are still gaps in treatment among those with documented dyslipidemia, principally among those calculated to have high or intermediate Framingham risk scores. Particular attention should also be paid to those at higher risk for not receiving treatment, including female patients and those within normal body mass index ranges.

Rosuvastatin as a Supplemental Treatment for the Clinical Symptoms of Nephropathia Epidemica: A Pilot Clinical Study

Nephropathis epidemica (NE), a mild form of hemorrhagic fever with renal syndrome (HFRS), is an acute zoonotic disease endemic in the Republic of Tatarstan. This study aimed to assess the impact of rosuvastatin on the clinical and laboratory results of NE. A total of 61 NE patients and 30 controls were included in this study; 22 NE patients and 7 controls received a daily dose of rosuvastatin (10 mg) for ten consecutive days. Serum samples were collected on days 1, 5, and 10 after admission to the hospital. These samples were analyzed to determine the levels of lipids, cytokines, and kidney toxicity markers. Our findings indicate that rosuvastatin reduced the duration of the second wave of fever and alleviated back pain and headache symptoms. Additionally, low-density lipoprotein cholesterol (LDL-C) serum levels were significantly decreased on days 5 and 10 upon rosuvastatin treatment. Furthermore, rosuvastatin decreased the levels of cytokines in the serum, particularly proinflammatory cytokines IL-1β and IL-8. NE patients had significantly altered levels of the kidney toxicity markers albumin and osteopontin. The data from our study provide evidence supporting the therapeutic potential of rosuvastatin in NE cases.

Glycosylation of blood cells during the onset and progression of atherosclerosis and myocardial infarction

Protein glycosylation controls cell-cell and cell-extracellular matrix (ECM) communication in immune, vascular, and inflammatory processes, underlining the critical role of this process in the identification of disease biomarkers and the design of novel therapies. Emerging evidence highlights the critical role of blood cell glycosylation in the pathophysiology of atherosclerosis (ATH) and myocardial infarction (MI). Here, we review the role of glycosylation in the interplay between blood cells, particularly erythrocytes, and endothelial cells (ECs), highlighting the involvement of this critical post/cotranslational modification in settings of cardiovascular disease (CVD). Importantly, we focus on emerging preclinical studies and clinical trials based on glycan-targeted drugs to validate their therapeutic potential. These findings may help establish new trends in preventive medicine and delineate novel targeted therapies in CVD.

Atherosclerosis and Inflammation: Insights from the Theory of General Pathological Processes

Recent advances have greatly improved our understanding of the molecular mechanisms behind atherosclerosis pathogenesis. However, there is still a need to systematize this data from a general pathology perspective, particularly with regard to atherogenesis patterns in the context of both canonical and non-classical inflammation types. In this review, we analyze various typical phenomena and outcomes of cellular pro-inflammatory stress in atherosclerosis, as well as the role of endothelial dysfunction in local and systemic manifestations of low-grade inflammation. We also present the features of immune mechanisms in the development of productive inflammation in stable and unstable plaques, along with their similarities and differences compared to canonical inflammation. There are numerous factors that act as inducers of the inflammatory process in atherosclerosis, including vascular endothelium aging, metabolic dysfunctions, autoimmune, and in some cases, infectious damage factors. Life-critical complications of atherosclerosis, such as cardiogenic shock and severe strokes, are associated with the development of acute systemic hyperinflammation. Additionally, critical atherosclerotic ischemia of the lower extremities induces paracoagulation and the development of chronic systemic inflammation. Conversely, sepsis, other critical conditions, and severe systemic chronic diseases contribute to atherogenesis. In summary, atherosclerosis can be characterized as an independent form of inflammation, sharing similarities but also having fundamental differences from low-grade inflammation and various variants of canonical inflammation (classic vasculitis).

Effect of the First Feeding on Enterocytes of Newborn Rats

The transcytosis of lipids through enterocytes occurs through the delivery of lipid micelles to the microvilli of enterocytes, consumption of lipid derivates by the apical plasma membrane (PM) and then their delivery to the membrane of the smooth ER attached to the basolateral PM. The SER forms immature chylomicrons (iChMs) in the ER lumen. iChMs are delivered at the Golgi complex (GC) where they are subjected to additional glycosylation resulting in maturation of iChMs. ChMs are secreted into the intercellular space and delivered into the lumen of lymphatic capillaries (LCs). The overloading of enterocytes with lipids induces the formation of lipid droplets inside the lipid bilayer of the ER membranes and transcytosis becomes slower. Here, we examined components of the enterocyte-to-lymphatic barriers in newly born rats before the first feeding and after it. In contrast to adult animals, enterocytes of newborns rats exhibited apical endocytosis and a well-developed subapical endosomal tubular network. These enterocytes uptake membranes from amniotic fluid. Then these membranes are transported across the polarized GC and secreted into the intercellular space. The enterocytes did not contain COPII-coated buds on the granular ER. The endothelium of blood capillaries situated near the enterocytes contained only a few fenestrae. The LCs were similar to those in adult animals. The first feeding induced specific alterations of enterocytes, which were similar to those observed after the lipid overloading of enterocytes in adult rats. Enlarged chylomicrons were stopped at the level of the LAMP2 and Neu1 positive post-Golgi structures, secreted, fused, delivered to the interstitial space, captured by the LCs and transported to the lymph node, inducing the movement of macrophages from lymphatic follicles into its sinuses. The macrophages captured the ChMs, preventing their delivery into the blood.

Role of Endothelial Regeneration and Overloading of Enterocytes with Lipids in Capturing of Lipoproteins by Basement Membrane of Rat Aortic Endothelium

Atherosclerosis is a complex non-monogenic disease related to endothelial damage in elastic-type arteries and incorrect feeding. Here, using cryodamage of endothelial cells (ECs) of rat abdominal aorta, we examined the role of the EC basement membrane (BM) for re-endothelization endothelial regeneration and its ability to capture low density lipoproteins (LDLs). Regeneration of endothelium induced thickening of the ECBM. Secretion of the BM components occurred in the G2-phase. Multiple regenerations, as well as arterial hypertension and aging, also led to the thickening of the BM. Under these conditions, the speed of re-endothelialization increased. The thick BM captured more LDLs. LDLs formed after overloading of rats with lipids acquired higher affinity to the BM, presumably due to the prolonged transport of chylomicrons through neuraminidase-positive endo-lysosomes. These data provide new molecular and cellular mechanisms of atherogenesis.