Oxysterols in Vascular Cells and Role in Atherosclerosis

Oxysterols, age-related-diseases and nutritherapy: Focus on 7-ketocholesterol and 7β-hydroxycholesterol

Age-related diseases are often associated with a disruption of RedOx balance that can lead to lipid peroxidation with the formation of oxysterols, especially those oxidized on carbon-7: 7-ketocholesterol (also known as 7-oxo-cholesterol) and 7β-hydroxycholesterol. Like cholesterol, these oxysterols have 27 carbons, they are composed of a sterane nucleus and have a hydroxyl function in position 3. The oxysterols 7-ketocholesterol and 7β-hydroxycholesterol are mainly formed by cholesterol autoxidation and are biomarkers of oxidative stress. These two oxysterols are frequently found at increased levels in the biological fluids (plasma, cerebrospinal fluid), tissues and/or organs (arterial wall, retina, brain) of patients with age-related diseases, especially cardiovascular diseases, neurodegenerative diseases (mainly Alzheimer's disease), ocular diseases (cataract, age-related macular degeneration), and sarcopenia. Depending on the cell type considered, 7-ketocholesterol and 7β-hydroxycholesterol induce either caspase- dependent or -independent types of cell death associated with mitochondrial and peroxisomal dysfunctions, autophagy and oxidative stress. The caspase dependent type of cell death associated with oxidative stress and autophagy is defined as oxiapoptophagy. These two oxysterols are also inducers of inflammation. These biological features associated with the toxicity of 7-ketocholesterol, and 7β-hydroxycholesterol are often observed in patients with age-related diseases, suggesting an involvement of these oxysterols in the pathophysiology of these disorders. The cytotoxic effects of 7-ketocholesterol and 7β-hydroxycholesterol are counteracted on different cell models by representative nutrients of the Mediterranean diet: ω3 and ω9 fatty acids, polyphenols, and tocopherols. There are also evidences, mainly in cardiovascular diseases, of the benefits of α-tocopherol and phenolic compounds. These in vitro and in vivo observations on 7-ketocholesterol and 7β-hydroxycholesterol, which are frequently increased in age-related diseases, reinforce the interest of nutritherapeutic treatments to prevent and/or cure age-related diseases currently without effective therapies.

Maternal high-fat diet exacerbates atherosclerosis development in offspring through epigenetic memory

Maternal exposure to a Western-type diet (WD) increases the susceptibility of adult offspring to atherosclerosis, partly because fetal endothelial cells (ECs) become dysfunctional and inflamed due to risk factors transmitted via maternal-fetal blood exchange. However, the underlying mechanisms remain unclear. Here we show that maternal WD accelerates atherogenesis in adult offspring mice by regulating chromatin dynamics through activator protein-1 (AP-1) in aortic ECs, inducing inflammatory memory at the chromatin level. We found that 27-hydroxycholesterol is involved in memory establishment and also acts as a secondary stimulator, amplifying the expression of inflammatory factors and enhancing the enrichment of AP-1/p300 and H3K27ac in ECs. Inhibiting AP-1 binding to chromatin reduced the inflammatory response in human umbilical vein ECs from mothers with hypercholesterolemia and decreased atherogenesis in offspring mice exposed to maternal WD. Our findings demonstrate that maternal WD exacerbates EC dysfunction and atherosclerosis in adult offspring by inducing AP-1-associated epigenetic memory, which increases chromatin accessibility to inflammatory genes.

Cardiometabolic Risk in Psoriatic Arthritis: A Hidden Burden of Inflammation and Metabolic Dysregulation

Psoriatic arthritis (PsA) is a chronic inflammatory disease that extends beyond musculoskeletal and dermatologic involvement to elevate cardiometabolic risk. Emerging evidence highlights the critical role of systemic inflammation in metabolic dysregulation, accelerating insulin resistance, dyslipidemia, and oxidative stress, all of which contribute to the increased burden of cardiovascular disease in PsA. This review explores the intricate interplay between inflammatory mediators-such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-17 (IL-17),-adipokine imbalances, and lipid metabolism abnormalities, all of which foster endothelial dysfunction and atherosclerosis. The dysregulation of adipokines, including leptin, adiponectin, and resistin, further perpetuates inflammatory cascades, exacerbating cardiovascular risk. Additionally, the metabolic alterations seen in PsA, particularly insulin resistance and lipid dysfunction, not only contribute to cardiovascular comorbidities but also impact disease severity and therapeutic response. Understanding these mechanistic links is imperative for refining risk stratification strategies and tailoring interventions. By integrating targeted immunomodulatory therapies with metabolic and cardiovascular risk management, a more comprehensive approach to PsA treatment can be achieved. Future research must focus on elucidating shared inflammatory and metabolic pathways, enabling the development of innovative therapeutic strategies to mitigate both systemic inflammation and cardiometabolic complications in PsA.

Plaque Stabilization and Regression, from Mechanisms to Surveillance and Clinical Strategies

With advances in therapies to reduce cardiovascular events and improvements in coronary imaging, an increasing number of clinical trials have demonstrated that treatments to reduce cardiovascular events in coronary artery disease are associated with favorable effects on atherosclerotic plaque size and characteristics. It has been observed that various drugs may induce plaque regression and enhance plaque stability after plaque formation. Numerous clinical trials have been conducted to verify the occurrence of plaque stabilization and regression and their beneficial effects on cardiovascular events. Using invasive imaging techniques such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT), researchers have been able to gather evidence supporting the existence of coronary plaque stabilization and regression. In this review, we explore the possible mechanisms of plaque stabilization and regression, summarize the imaging features of plaque stabilization and regression, and assemble the evidence from clinical studies that have used different features as observational endpoints.

Determination of selected oxysterol levels, oxidative stress, and macrophage activation indicators in children and adolescents with familial hypercholesterolemia

AIM

Elevated levels of cholesterol in the bloodstream, also referred to as hypercholesterolemia, pose a significant risk for the onset of cardiovascular and cerebrovascular diseases. Oxysterols, cholesterol-derived oxidized compounds that form enzymatically or non-enzymatically, contribute to the development of atherosclerosis and coronary artery disease. This study aimed to examine the critical oxysterol levels in children and adolescents with hypercholesterolemia and explore the correlation between these levels, oxidative stress, and atherosclerosis progression.

MATERIALS AND METHODS

The study included 20 patients with familial hypercholesterolemia (FH) and 20 healthy individuals aged between 6 and 18 years. Participants were categorized into children (6-9 years) and adolescents (10-18 years). Pediatric and adolescent patients were selected from among subjects with LDL-C ≥ 130 mg/dL and diagnosed with heterozygous familial hypercholesterolemia (HeFH) based on the presence of mutations in the LDL receptor (LDL-R) gene. Patients with HeFH who were receiving regular atorvastatin therapy were included in the study.

RESULTS

There were no notable differences in catalase and paraoxonase (PON1) activities among the groups. However, the patient group displayed substantially higher levels of malondialdehyde (MDA) (P = 0.0108) and superoxide dismutase (SOD) activity (P = 0.0103). Compared to the healthy control group, serum chitotriosidase (CHITO) activity (P = 0.037) and chitinase 3-like protein 1 (YKL-40) levels (P = 0.0027) were significantly elevated in the patient group. Furthermore, the carotid intima-media thickness (CIMT) measurements of the patient group were significantly greater than those of the healthy group (**P < 0.0001****). The patient group exhibited significantly elevated levels of 5,6-α-epoxycholesterol, Cholestane-3β,5α,6β-triol (C-triol), and 7-ketocholesterol (7-KC), whereas 27-hydroxycholesterol (27-OHC) was significantly more abundant in the healthy group. On the other hand, while 27-OHC/Total cholesterol (Total-C) levels were significantly higher in healthy individuals, the C-Triol/Total-C ratio was significantly higher in patients. No significant differences were found between the groups in terms of 7-KC/Total-C and 5,6-α-epoxycholesterol/Total-C levels.

CONCLUSION

This study highlights the key roles of oxysterols, oxidative stress, and macrophage activation in the development of atherosclerosis in pediatric and adolescent patients with FH. Elevated C-Triol levels in FH patients, alongside increased CIMT, point to early vascular changes despite atorvastatin therapy. In contrast, higher 27-OHC levels in healthy controls suggest differential oxysterol regulation due to cholesterol-lowering treatments in FH patients. C-Triol and 27-OHC/Total-C ratios showed potential as biomarkers to distinguish patients with FH. These findings emphasize the need for therapies targeting oxidative stress and macrophage activation in addition to cholesterol-lowering interventions.

The colonic polyphenol catabolite dihydroferulic acid (DHFA) regulates macrophages activated by oxidized LDL, 7-ketocholesterol, and LPS switching from pro- to anti-inflammatory mediators

Macrophage activation plays a central role in the development of atherosclerotic plaques. Interaction with oxidized low-density lipoprotein (oxLDL) leads to macrophage differentiation into foam cells and oxylipin production, contributing to plaque formation. 7-Ketocholesterol (7KC) is an oxidative byproduct of cholesterol found in oxLDL particles and is considered a factor contributing to plaque progression. During atherosclerotic lesion regression or stabilization, macrophages undergo a transformation from a pro-inflammatory phenotype to a reparative anti-inflammatory state. Interleukin-10 (IL-10) and PGE1 appear to be crucial in resolving both acute and chronic inflammatory processes. After coffee consumption, the gut microbiota processes non-absorbed chlorogenic acids producing various lower size phenolic acids. These colonic catabolites, including dihydroferulic acid (DHFA), may exert various local and systemic effects. We focused on DHFA's impact on inflammation and oxidative stress in THP-1 macrophages exposed to oxLDL, 7KC, and lipopolysaccharides (LPS). Our findings reveal that DHFA inhibits the release of several pro-inflammatory mediators induced by LPS in macrophages, such as CCL-2, CCL-3, CCL-5, TNF-α, IL-6, and IL-17. Furthermore, DHFA reduces IL-18 and IL-1β secretion in an inflammasome-like model. DHFA demonstrated additional benefits: it decreased oxLDL uptake and CD36 expression induced by oxLDL, regulated reactive oxygen species (ROS) and 8-isoprostane secretion (indicating oxidative stress modulation), and selectively increased IL-10 and PGE1 levels in the presence of inflammatory stimuli (LPS and 7KC). Finally, our study highlights the pivotal role of PGE1 in foam cell inhibition and inflammation regulation within activated macrophages. This study highlights DHFA's potential as an antioxidant and anti-inflammatory agent, particularly due to its ability to induce PGE1 and IL-10.

Aging-Related Sarcopenia: Metabolic Characteristics and Therapeutic Strategies

The proportion of the elderly population is gradually increasing as a result of medical care advances, leading to a subsequent surge in geriatric diseases that significantly impact quality of life and pose a substantial healthcare burden. Sarcopenia, characterized by age-related decline in skeletal muscle mass and quality, affects a considerable portion of older adults, particularly the elderly, and can result in adverse outcomes such as frailty, fractures, bedridden, hospitalization, and even mortality. Skeletal muscle aging is accompanied by underlying metabolic changes. Therefore, elucidating these metabolic profiles and specific mechanisms holds promise for informing prevention and treatment strategies for sarcopenia. This review provides a comprehensive overview of the key metabolites identified in current clinical studies on sarcopenia and their potential pathophysiological alterations in metabolic activity. Besides, we examine potential therapeutic strategies for sarcopenia from a perspective focused on metabolic regulation.

High-Density Lipoprotein Is Located Alongside Insulin in the Islets of Langerhans of Normal and Rodent Models of Diabetes

Recent studies have implicated pre-beta and beta lipoproteins (VLDL and LDL) in the etiopathogenesis of complications of diabetes mellitus (DM). In contrast, alpha lipoprotein (HDL) is protective of the beta cells of the pancreas. This study examined the distribution of HDL in the islets of Langerhans of murine models of type 1 diabetic rats (streptozotocin (STZ)-induced DM in Wistar rats) and type 2 models of DM rats (Goto-Kakizaki (GK), non-diabetic Zucker lean (ZL), and Zucker diabetic and fatty (ZDF)). The extent by which HDL co-localizes with insulin or glucagon in the islets of the pancreas was also investigated. Pancreatic tissues of Wistar non-diabetic, diabetic Wistar, GK, ZL, and ZDF rats were processed for immunohistochemistry. Pancreatic samples of GK rats fed with either a low-fat or a high-fat diet were prepared for transmission immune-electron microscopy (TIEM) to establish the cytoplasmic localization of HDL in islet cells. HDL was detected in the core and periphery of pancreatic islets of Wistar non-diabetic and diabetic, GK, ZL, and ZDF rats. The average total of islet cells immune positive for HDL was markedly (<0.05) reduced in GK and ZDF rats in comparison to Wistar controls. The number of islet cells containing HDL was also remarkably (p < 0.05) reduced in Wistar diabetic rats and GK models fed on high-fat food. The co-localization study using immunofluorescence and TIEM techniques showed that HDL is detected alongside insulin within the secretory granules of β-cells. HDL did not co-localize with glucagon. This observation implies that HDL may contribute to the metabolism of insulin.