Therapeutic strategy for atherosclerosis based on bone-vascular axis hypothesis

The role of lipid metabolism in osteoporosis: Clinical implication and cellular mechanism

In recent years, researchers have become focused on the relationship between lipids and bone metabolism balance. Moreover, many diseases related to lipid metabolism disorders, such as nonalcoholic fatty liver disease, atherosclerosis, obesity, and menopause, are associated with osteoporotic phenotypes. It has been clinically observed in humans that these lipid metabolism disorders promote changes in osteoporosis-related indicators bone mineral density and bone mass. Furthermore, similar osteoporotic phenotype changes were observed in high-fat and high-cholesterol-induced animal models. Abnormal lipid metabolism (such as increased oxidized lipids and elevated plasma cholesterol) affects bone microenvironment homeostasis via cross-organ communication, promoting differentiation of mesenchymal stem cells to adipocytes, and inhibiting commitment towards osteoblasts. Moreover, disturbances in lipid metabolism affect the bone metabolism balance by promoting the secretion of cytokines such as receptor activator of nuclear factor-kappa B ligand by osteoblasts and stimulating the differentiation of osteoclasts. Conclusively, this review addresses the possible link between lipid metabolism disorders and osteoporosis and elucidates the potential modulatory mechanisms and signaling pathways by which lipid metabolism affects bone metabolism balance. We also summarize the possible approaches and prospects of intervening lipid metabolism for osteoporosis treatment.

Imaging of the brain-heart axis: prognostic value in a European setting

BACKGROUND AND AIMS

Increasing data suggest that stress-related neural activity (SNA) is associated with subsequent major adverse cardiovascular events (MACE) and may represent a therapeutic target. Current evidence is exclusively based on populations from the U.S. and Asia where limited information about cardiovascular disease risk was available. This study sought to investigate whether SNA imaging has clinical value in a well-characterized cohort of cardiovascular patients in Europe.

METHODS

In this single-centre study, a total of 963 patients (mean age 58.4 ± 16.1 years, 40.7% female) with known cardiovascular status, ranging from 'at-risk' to manifest disease, and without active cancer underwent 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography between 1 January 2005 and 31 August 2019. Stress-related neural activity was assessed with validated methods and relations between SNA and MACE (non-fatal stroke, non-fatal myocardial infarction, coronary revascularization, and cardiovascular death) or all-cause mortality by time-to-event analysis.

RESULTS

Over a maximum follow-up of 17 years, 118 individuals (12.3%) experienced MACE, and 270 (28.0%) died. In univariate analyses, SNA significantly correlated with an increased risk of MACE (sub-distribution hazard ratio 1.52, 95% CI 1.05-2.19; P = .026) or death (hazard ratio 2.49, 95% CI 1.96-3.17; P < .001). In multivariable analyses, the association between SNA imaging and MACE was lost when details of the cardiovascular status were added to the models. Conversely, the relationship between SNA imaging and all-cause mortality persisted after multivariable adjustments.

CONCLUSIONS

In a European patient cohort where cardiovascular status is known, SNA imaging is a robust and independent predictor of all-cause mortality, but its prognostic value for MACE is less evident. Further studies should define specific patient populations that might profit from SNA imaging.

Natural products in atherosclerosis therapy by targeting PPARs: a review focusing on lipid metabolism and inflammation

Inflammation and dyslipidemia are critical inducing factors of atherosclerosis. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors and control the expression of multiple genes that are involved in lipid metabolism and inflammatory responses. However, synthesized PPAR agonists exhibit contrary therapeutic effects and various side effects in atherosclerosis therapy. Natural products are structural diversity and have a good safety. Recent studies find that natural herbs and compounds exhibit attractive therapeutic effects on atherosclerosis by alleviating hyperlipidemia and inflammation through modulation of PPARs. Importantly, the preparation of natural products generally causes significantly lower environmental pollution compared to that of synthesized chemical compounds. Therefore, it is interesting to discover novel PPAR modulator and develop alternative strategies for atherosclerosis therapy based on natural herbs and compounds. This article reviews recent findings, mainly from the year of 2020 to present, about the roles of natural herbs and compounds in regulation of PPARs and their therapeutic effects on atherosclerosis. This article provides alternative strategies and theoretical basis for atherosclerosis therapy using natural herbs and compounds by targeting PPARs, and offers valuable information for researchers that are interested in developing novel PPAR modulators.

Yang-Xin-Shu-Mai granule alleviates atherosclerosis by regulating macrophage polarization via the TLR9/MyD88/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Previous studies have found that Yang-Xin-Shu-Mai granule (YXSMG) has certain advantages in the treatment of stable coronary heart disease. However, YXSMG can inhibit the progression of atherosclerotic plaque and stabilize vulnerable plaque needs to be further explored and studied. This research, mass spectrometry analysis, network pharmacology, in vivo and in vitro experimental studies were conducted to explore the mechanism of YXSMG on atherosclerosis.

AIM OF THE STUDY

To decipher the mechanism of atherosclerotic plaque, stabilization for YXSMG by analysis of its active ingredients and biological network and activity in whole animal and at cellular and molecular levels.

METHODS

The active components of YXSMG were determined using high performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS) analysis. The 'Disease-Compound-Target-Pathway' network diagram was constructed using network pharmacology, and the stability of binding between core targets and core compounds was analyzed with molecular docking. After intervention with YXSMG, the pathology of aortic plaque, inflammation in the surrounding tissue, expression of TLR9/MyD88/NF-κB pathway protein in plaque and M1/M2 polarization of plaque macrophages were evaluated in vivo in apolipoprotein E-deficient (ApoE-/-) mice fed with high-fat diet. To verify whether it suppressed inflammation by inhibiting Toll-like receptor 9 (TLR9) reprogramming of macrophage polarization, we used RAW264.7 macrophages treated with specific TLR9 agonist (ODN1826) and inhibitor (ODN2088).

RESULTS

Five active compounds were identified in YXSMG: catechin, formononetin, tanshinone IIA, cryptotanshinone and glycitein. Network pharmacology studies revealed TLR9 as one of the core targets of YXSMG intervention in atherosclerosis. Computer simulation of molecular docking showed that TLR9 could interact with the core compound to form a stable complex. In vivo experiments confirmed that YXSMG could significantly inhibit atherosclerotic plaque, reduce levels of blood lipids and inflammatory factors, downregulate TLR9/MyD88/NF-κB pathway protein and inhibit aortic sinus macrophages polarization to M1, but promote their polarization to M2 to inhibit inflammation. In vitro experiments revealed that YXSMG could downregulate expression of TLR9 gene and protein in ODN1826-activated RAW264.7 macrophages. ODN2088 had a synergistic effect with YXSMG on the TLR9/MyD88/NF-κB signaling pathway, and reprogrammed macrophages polarization from M1 to M2 by inhibiting TLR9, thus reducing immuno-inflammatory response.

CONCLUSION

YXSMG can reduce the level of blood lipid and improve the size of atherosclerotic plaque and inflammatory infiltration in ApoE-/- mice fed with high fat. It is concluded that YXSMG can improve the mechanism of atherosclerotic plaque by inhibiting TLR9/MyD88/NF-κB pathway reprogramming macrophage M1/M2 polarization and reducing arterial inflammation.

Kefir peptides attenuate atherosclerotic vascular calcification and osteoporosis in atherogenic diet-fed ApoE−/− knockout mice

Aims: Vascular calcification (VC) and osteoporosis were previously considered two distinct diseases. However, current understanding indicates that they share common pathogenetic mechanisms. The available medicines for treating VC and osteoporosis are limited. We previously demonstrated that kefir peptides (KPs) alleviated atherosclerosis in high-fat diet (HFD)-induced apolipoprotein E knockout (ApoE−/−) mice. The present study further addressed the preventive effects of KPs on VC and osteoporosis in ApoE−/− mice fed a high-cholesterol atherogenic diet (AD).

Main methods: Seven-week-old ApoE−/− and wild-type C57BL/6 mice were randomly divided into five groups (n = 6). The development of VC and osteoporosis was evaluated after AD feeding for 13 weeks in KP-treated ApoE−/− mice and compared to C57BL/6 and ApoE−/− mice fed a standard chow diet (CD).

Key findings: The results indicated that KP-treated ApoE−/− mice exhibited lower serum total cholesterol, oxidized low-density lipoprotein (ox-LDL), malondialdehyde (MDA) levels, and serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and creatine kinase (CK) activities, which suggested that KPs prevented hyperlipidemia and possible damages to the liver and muscle in ApoE−/− mice. KPs reduced serum tumor necrosis factor-α (TNF-α) and the local expression of TNF-α, IL-1β, and macrophage-specific CD68 markers in aortic tissues, which suggested that KPs inhibited inflammatory responses in AD-fed ApoE−/− mice. KPs reduced the deposition of lipid, collagen, and calcium minerals in the aortic roots of AD-fed ApoE−/− mice, which suggested that KPs inhibited the calcific progression of atherosclerotic plaques. KPs exerted osteoprotective effects in AD-fed ApoE−/− mice, which was evidenced by lower levels of the bone resorption marker CTX-1 and higher levels of the bone formation marker P1NP. KPs improved cortical bone mineral density and bone volume and reduced trabecular bone loss in femurs.

Significance: The present data suggested that KPs attenuated VC and osteoporosis by reducing oxidative stress and inflammatory responses in AD-fed ApoE−/− mice. Our findings contribute to the application of KPs as preventive medicines for the treatment of hyperlipidemia-induced vascular and bone degeneration.

Impact of Metabolic Activity of Vertebra and Amygdala on Stroke Recurrence: A Prospective Cohort Study

BACKGROUND

Elevated metabolic activity of amygdala is known to be related to atherosclerotic cardiovascular event by increasing inflammatory cell production from bone marrow. We tried to identify the factors of metabolic activity in the amygdala, vertebrae, liver, spleen, and internal carotid artery related to the future vascular events after stroke.

METHODS

A total of 110 patients with acute stroke were included (72±10 years of age, 39% women) and underwent whole-body ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography between August 1, 2015 and February 28, 2020. We compared the FDG uptake in the amygdala, vertebrae, liver, spleen, and internal carotid artery between patients with and without recurrent vascular event. Cox proportional hazards model was used to identify factors related to recurrent stroke and vascular event.

RESULTS

During the median follow-up period of 18 months, 22 patients experienced vascular events, including 15 stroke recurrence. Patients with recurred vascular event had a significantly higher FDG uptake in the amygdala and vertebrae than those without. The Cox proportional hazard model including diabetes, renal function, and carotid stenosis showed that a higher FDG uptake in the amygdala was independently associated with total vascular events (hazard ratio, 3.11 [95% CI, 1.11-8.70]) and higher FDG uptake in the vertebrae with stroke recurrence (hazard ratio, 4.94 [95% CI, 1.29-18.9]).

CONCLUSIONS

The increased metabolic activities of the vertebrae and amygdala are related to future vascular event among stroke survivors.

Functional Impairment of Endothelial Colony Forming Cells (ECFC) in Patients with Severe Atherosclerotic Cardiovascular Disease (ASCVD)

Endothelial dysfunction is a key factor in atherosclerosis. However, the link between endothelial repair and severity of atherosclerotic cardiovascular disease (ASCVD) is unclear. This study investigates the relationship between ASCVD, markers of inflammation, and circulating endothelial progenitor cells, namely hematopoietic cells with paracrine angiogenic activity and endothelial colony forming cells (ECFC). Two hundred and forty-three subjects from the TELARTA study were classified according to the presence of clinical atherosclerotic disease. ASCVD severity was assessed by the number of involved vascular territories. Flow cytometry was used to numerate circulating progenitor cells (PC) expressing CD34 and those co-expressing CD45, CD34, and KDR. Peripheral blood mononuclear cells ex vivo culture methods were used to determine ECFC and Colony Forming Unit- endothelial cells (CFU-EC). The ECFC subpopulation was analyzed for proliferation, senescence, and vasculogenic properties. Plasma levels of IL-6 and VEGF-A were measured using Cytokine Array. Despite an increased number of circulating precursors in ASCVD patients, ASCVD impaired the colony forming capacity and the angiogenic properties of ECFC in a severity-dependent manner. Alteration of ECFC was associated with increased senescent phenotype and IL-6 levels. Our study demonstrates a decrease in ECFC repair capacity according to ASCVD severity in an inflammatory and senescence-associated secretory phenotype context.

Reduced hip bone mineral density is associated with high levels of calciprotein particles in patients with Fabry disease

Calciprotein particles (CPP) are nanoscale mineralo-protein aggregates that help stabilize excess mineral in the circulation. We examined the relationship between CPP and bone mineral density in Fabry disease patients. We found an inverse correlation with total hip and femoral neck density, but none with lumbar spine.

PURPOSE

Calciprotein particles (CPP) are colloidal mineral-protein complexes made up primarily of the circulating glycoprotein fetuin-A, calcium, and phosphate. They form in extracellular fluid and facilitate the stabilization, transport, and clearance of excess minerals from the circulation. While most are monomers, they also exist in larger primary (CPP-I) and secondary (CPP-II) form, both of which are reported to be raised in pathological states. This study sought to investigate CPP levels in the serum of patients with Fabry disease, an X-linked systemic lysosomal storage disorder that is associated with generalized inflammation and low bone mineral density (BMD).

METHODS

We compared serum CPP-I and CPP-II levels in 59 patients with Fabry disease (37 female) with levels in an age-matched healthy adult cohort (n=28) and evaluated their association with BMD and biochemical data obtained from routine clinical review.

RESULTS

CPP-I and CPP-II levels were higher in male Fabry disease patients than female sufferers as well as their corresponding sex- and age-matched controls. CPP-II levels were inversely correlated with BMD at the total hip and femoral neck, but not the lumbar spine. Regression analyses revealed that these associations were independent of common determinants of BMD, but at the femoral neck, a significant association was only found in female patients.

CONCLUSION

Low hip BMD was associated with high CPP-II in patients with Fabry disease, but further work is needed to investigate the relevance of sex-related differences and to establish whether CPP measurement may aid assessment of bone disease in this setting.

Vascular Calcification: New Insights Into BMP Type I Receptor A

Vascular calcification (VC) is a complex ectopic calcification process and an important indicator of increased risk for diabetes, atherosclerosis, chronic kidney disease, and other diseases. Therefore, clarifying the pathogenesis of VC is of great clinical significance. Numerous studies have shown that the onset and progression of VC are similar to bone formation. Members of the bone morphogenetic protein (BMP) family of proteins are considered key molecules in the progression of vascular calcification. BMP type I receptor A (BMPR1A) is a key receptor of BMP factors acting on the cell membrane, is widely expressed in various tissues and cells, and is an important “portal” for BMP to enter cells and exert their biological effect. In recent years, many discoveries have been made regarding the occurrence and treatment of ectopic ossification-related diseases involving BMP signaling targets. Studies have confirmed that BMPR1A is involved in osteogenic differentiation and that its high expression in vascular endothelial cells and smooth muscle cells can lead to vascular calcification. This article reviews the role of BMPR1A in vascular calcification and the possible underlying molecular mechanisms to provide clues for the clinical treatment of such diseases.

Reduction of Calciprotein Particles in Adults Receiving Infliximab for Chronic Inflammatory Disease

Patients with chronic inflammatory diseases (CID) experience accelerated loss of bone mineral density, which is often accompanied by increased vascular calcification. These disturbances can be attenuated by therapies for inflammation, such as the tumor necrosis factor inhibitor infliximab. Calciprotein particles (CPP) are circulating colloidal aggregates of calcium and phosphate together with the mineral-binding protein fetuin-A, which have emerged as potential mediators of vascular calcification. The precise origins of serum CPP are unclear, but bone turnover may be an important source. In this longitudinal observational study, we studied patients with CID undergoing treatment with infliximab to assess the temporal relationship between bone turnover and circulating CPP. Ten patients with active CID receiving infliximab induction therapy and an additional 3 patients with quiescent CID on maintenance infliximab therapy were studied for 8 weeks with repeated measures of bone turnover markers as well as CPP (calciprotein monomers [CPM], primary CPP [CPP-I], and secondary CPP [CPP-II]). Therapeutic response was appraised using validated disease activity scores. At baseline, those with active CID had elevated markers of bone resorption and suppressed bone formation markers as well as higher CPM and CPP-I compared with those with quiescent CID. In responders, there was an early but transient reduction in resorption markers by week 1, but a more sustained increase in bone formation markers compared with non-responders at week 8. This was accompanied by reductions in CPM (β = -6.5 × 10³ AU [95% CI -11.1, -1.8], p = 0.006) and CPP-I (β = -23.4 × 10⁴ particles/mL [95% CI -34.8, -11.9], p < 0.001). In contrast, no significant changes in any markers were observed in non-responders or those receiving maintenance therapy. Thus, CPP have a dynamic association with changes in bone turnover in response to infliximab therapy, adding to accumulating evidence of the role of bone as a determinant of systemic levels. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Decreased 18F-Fluorodeoxyglucose Uptake in Lumbar Vertebrae of Stroke Patients

BACKGROUND AND PURPOSE

We investigated ^18F-fluorodeoxyglucose (FDG) uptake levels in the lumbar vertebrae, liver, and spleen of stroke patients with carotid atherosclerosis.

METHODS

This study analyzed acute ischemic stroke patients with carotid atherosclerosis who underwent whole-body FDG positron-emission tomography between October 2015 and January 2017. FDG uptake in the lumbar vertebrae, liver, and spleen was measured and compared between stroke patients and control subjects without stroke history. Multivariate linear regression analysis was performed to identify independent factors related to FDG uptake in the proximal internal carotid artery (ICA).

RESULTS

Twenty stroke patients aged 75.1±9.0 years (mean±standard deviation; 10 females) and 20 control subjects aged 62.9±10.7 years (6 females) were included. In comparison with the control group, the stroke group showed significantly higher FDG uptake in the proximal ICA (1.16±0.26 vs. 0.87±0.19, p<0.01), but significantly lower FDG uptake in the lumbar vertebrae (1.09±0.26 vs. 1.38±0.38, p=0.007) and liver (1.71±0.30 vs. 2.01±0.34, p=0.005). Multivariate linear regression analysis showed that the lumbar FDG uptake was negatively correlated with FDG uptake in the proximal ICA (standardized coefficient=-0.367, p=0.013) after adjusting for age and hypertension.

CONCLUSIONS

Stroke patients showed decreased FDG uptake in the lumbar vertebrae. Further studies are warranted to evaluate the pathophysiological link between cerebral atherosclerosis and bone.

Association of Bone Mineral Density to Cerebral Small Vessel Disease Burden

OBJECTIVE

To test the hypothesis that bone mineral loss is mechanistically related to cerebral small vessel disease (SVD), we investigated the relationship between bone mineral density and the prevalence and intensity of SVD among patients with stroke.

METHODS

We analyzed data of 1,190 consecutive patients with stroke who were >50 years of age and underwent both brain MRI and dual-energy x-ray absorptiometry from the stroke registry of Chung-Ang University Hospital in Seoul, Korea. The patients were categorized into 3 groups according to their bone mineral density (normal, osteopenia, and osteoporosis). White matter hyperintensities, silent lacunes, cerebral microbleeds, and extensive perivascular space were assessed from brain MRI. Multinomial logistic regression model was used to examine the association between osteoporosis and total SVD score. We also recruited 70 patients with stroke to study serum bone turnover markers and microRNAs related to both cerebral atherosclerosis and bone metabolism to understand bone and brain interaction.

RESULTS

Osteoporosis was determined among 284 patients (23.9%), and 450 patients (37.8%) had osteopenia. As bone mineral density decreased, total SVD score and the incidence of every SVD phenotype increased except strictly lobar cerebral microbleeds. Multinomial logistic regression analysis showed that osteoporosis was independently associated with severe SVD burden. The levels of microRNA-378f were significantly increased among the patients with osteoporosis and maximal total SVD score and positively correlated with parathyroid hormone and osteocalcin.

CONCLUSIONS

These findings suggest a pathophysiologic link between bone mineral loss and hypertensive cerebral arteriolar degeneration, possibly mediated by circulating microRNA.

Shuxuetong injection simultaneously ameliorates dexamethasone-driven vascular calcification and osteoporosis

Osteoporosis (OP) and vascular calcification (VC) share a number of common risk factors, pathophysiological mechanisms and etiology, which are known as bone-vascular axis. The present study aimed to investigate the effects of Shuxuetong (SXT) injection on VC and osteoporosis. A rat model of VC and osteoporosis was induced by dexamethasone (DEX; 1 mg/kg/day for 4 weeks, intramuscularly). Simultaneously, 0.6 ml/kg/day SXT was intraperitoneally injected. Compared with control rats, DEX induced significantly more VC and OP, as determined by increased calcium deposition and alkaline phosphatase activity in the aorta, disturbed structure, decreased levels of cortical bone thickness and trabecular bone area, and increased apoptosis in the bone. SXT injection ameliorated DEX-induced VC and osteoporosis; furthermore, the osteoblastic differentiation of vascular smooth muscle cells and the activation of endoplasmic reticulum stress in the DEX group was also prevented by SXT injection. Compared with control rats, protein expression levels of sclerostin, a crucial crosslink of the bone-vascular axis, were significantly increased in the aorta and bone of rats with DEX, which was also attenuated by SXT injection. Thus, the present study suggested that SXT injection could ameliorate both VC and OP, and may be mediated by the regulation of sclerostin. The present study may provide the basis a novel strategy for the prevention and treatment of VC and OP, which emerge as side-effects of glucocorticoids.

Docosahexaenoic acid nanoencapsulated with anti-PECAM-1 as co-therapy for atherosclerosis regression

Atherosclerosis is a non-resolving inflammatory condition that underlies major cardiovascular diseases.Recent clinical trial using an anti-inflammatory drug has showna reduction of cardiovascular mortality, but increased the susceptibility to infections. For this reason, tissue target anti-inflammatory therapies can represent a better option to regress atherosclerotic plaques. Docosahexaenoic acid (DHA) is a natural omega 3 fatty acidcomponentof algae oil and acts asaprecursor of several anti-inflammatory compounds, such the specialized proresolving lipid mediators(SPMs). During the atherosclerosis process, the inflammatory condition of the endothelium leads to the higher expression of adhesion molecules, such as Endothelial Cell Adhesion Molecule Plate 1 (PECAM-1 or CD31), as part of the innate immune response. Thus, the objective of this study was to develop lipid-core nanocapsules with DHA constituting the nucleus and anti-PECAM-1 on their surface and drive this structure to the inflamed endothelium. Nanocapsules were prepared by interfacial deposition of pre-formed polymer method. Zinc-II was added to bind anti-PECAM-1 to the nanocapsule surface by forming an organometallic complex. Swelling experiment showed that the algae oil act as non-solvent for the polymer (weight constant weight for 60 days, p > 0.428) indicating an adequate material to produce kinetically stable lipid-core nanocapsules (LNC). Five formulations were synthesized: Lipid-core nanocapsules containing DHA (LNC-DHA) or containing Medium-chain triglycerides (LNC-MCT), multi-wall nanocapsules containing DHA (MLNC-DHA) or containing MCT (MLNC-MCT) and the surface-functionalized (anti-PECAM-1) metal-complex multi-wall nanocapsules containing DHA (MCMN-DHA-a1). All formulations showed homogeneous macroscopic aspects without aggregation. The mean size of the nanocapsules measured by laser diffraction did not show difference among the samples (p = 0.241). Multi-wall nanocapsules (MLNC) showed a slight increase in the mean diameter and polydispersity index (PDI) measured by DLS, lower pH and an inversion in the zeta-potential (ξP) compared to LNCs. Conjugation test for anti-PECAM-1 showed 94.80% of efficiency. The mean diameter of the formulation had slightly increased from 160 nm (LCN-DHA) and 162 nm (MLNC-DHA) to 164 nm (MCMN-DHA-a1) indicating that the surface functionalization did not induce aggregation of the nanocapsules. Biological assays showed that the MCMN-DHA-a1 were uptaken by the HUVEC cells and did not decrease their viability. The surface-functionalized (anti- PECAM-1) metal-complex multi-wall nanocapsules containing DHA (MCMN-DHA-a1) can be considered adequate for pharmaceutical approaches.

Aryl hydrocarbon receptor connects dysregulated immune cells to atherosclerosis

As a chronic inflammatory disease with autoimmune components, atherosclerosis is the major cause of cardiovascular morbidity and mortality. Recent studies have revealed that the development of atherosclerosis is strongly linked to the functional activities of aryl hydrocarbon receptor (AHR), a chemical sensor that is also important for the development, maintenance, and function of a variety of immune cells. In this review, we focus on the impact of AHR signaling on the different cell types that are closely related to the atherogenesis, including T cells, B cells, dendritic cells, macrophages, foam cells, and hematopoietic stem cells in the arterial walls, and summarize the latest development on the interplay between this environmental sensor and immune cells in the context of atherosclerosis. Hopefully, elucidation of the role of AHR in atherosclerosis will facilitate the understanding of case variation in disease prevalence and may aid in the development of novel therapies.

The roles of non-coding RNAs in vascular calcification and opportunities as therapeutic targets

Vascular calcification (VC) is characterized by an accumulation of calcium phosphate crystals inside the vessel wall. VC is often associated with diabetes, chronic kidney disease (CKD), atherosclerosis, and cardiovascular disease (CVD). Even though the number of patients with VC remains prevalent, there are still no approved therapies for the treatment of VC. Since the pathogenesis of VC is diverse and involves multiple factors and mechanisms, it is critical to reveal the novel mechanisms involved in VC. Although protein-coding RNAs involved in VC have been extensively studied, the roles of non-coding RNAs (ncRNAs) are not yet fully understood. The field of ncRNAs has recently received attention, and accumulating evidence from studies in VC suggests that ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play an important role in the regulation of VC. NcRNAs can modulate VC by acting as promoters or inhibitors and may be useful in the clinical diagnosis and treatment of VC. In this article, we review and discuss ncRNAs that regulate VC and present the therapeutic implications of these ncRNAs.

Klotho Pathways, Myelination Disorders, Neurodegenerative Diseases, and Epigenetic Drugs

In this review we outline a rationale for identifying neuroprotectants aimed at inducing endogenous Klotho activity and expression, which is epigenetic action, by definition. Such an approach should promote remyelination and/or stimulate myelin repair by acting on mitochondrial function, thereby heralding a life-saving path forward for patients suffering from neuroinflammatory diseases. Disorders of myelin in the nervous system damage the transmission of signals, resulting in loss of vision, motion, sensation, and other functions depending on the affected nerves, currently with no effective treatment. Klotho genes and their single-pass transmembrane Klotho proteins are powerful governors of the threads of life and death, true to the origin of their name, Fates, in Greek mythology. Among its many important functions, Klotho is an obligatory co-receptor that binds, activates, and/or potentiates critical fibroblast growth factor activity. Since the discovery of Klotho a little over two decades ago, it has become ever more apparent that when Klotho pathways go awry, oxidative stress and mitochondrial dysfunction take over, and age-related chronic disorders are likely to follow. The physiological consequences can be wide ranging, potentially wreaking havoc on the brain, eye, kidney, muscle, and more. Central nervous system disorders, neurodegenerative in nature, and especially those affecting the myelin sheath, represent worthy targets for advancing therapies that act upon Klotho pathways. Current drugs for these diseases, even therapeutics that are disease modifying rather than treating only the symptoms, leave much room for improvement. It is thus no wonder that this topic has caught the attention of biomedical researchers around the world.