Endothelial function and dysfunction: Impact of metformin

Targeting oxidative stress in preeclampsia

Preeclampsia is a complex condition characterized by elevated blood pressure and organ damage involving kidneys or liver, resulting in significant morbidity and mortality for both the mother and the fetus. Increasing evidence suggests that oxidative stress, often caused by mitochondrial dysfunction within fetal trophoblast cells may play a major role in the development and progression of preeclampsia. Oxidative stress occurs as a result of an imbalance between the production of reactive oxygen species (ROS) and the capacity of antioxidant defenses, which can lead to placental cellular damage and endothelial cell dysfunction. Targeting oxidative stress appears to be a promising therapeutic approach that has the potential to improve both short- and long-term maternal and fetal outcomes, thus reducing the global burden of preeclampsia. The purpose of this review is to provide a comprehensive account of the mechanisms of oxidative stress in preeclampsia. Furthermore, it also examines potential interventions for reducing oxidative stress in preeclampsia, including natural antioxidant supplements, lifestyle modifications, mitochondrial targeting antioxidants, and pharmacological agents.A better understanding of the mechanism of action of proposed therapeutic strategies targeting oxidative stress is essential for the identification of companion biomarkers and personalized medicine approaches for the development of effective treatments of preeclampsia.

Enhancing immunity during ageing by targeting interactions within the tissue environment

Immunity declines with age. This results in a higher risk of age-related diseases, diminished ability to respond to new infections and reduced response to vaccines. The causes of this immune dysfunction are cellular senescence, which occurs in both lymphoid and non-lymphoid tissue, and chronic, low-grade inflammation known as 'inflammageing'. In this Review article, we highlight how the processes of inflammation and senescence drive each other, leading to loss of immune function. To break this cycle, therapies are needed that target the interactions between the altered tissue environment and the immune system instead of targeting each component alone. We discuss the relative merits and drawbacks of therapies that are directed at eliminating senescent cells (senolytics) and those that inhibit inflammation (senomorphics) in the context of tissue niches. Furthermore, we discuss therapeutic strategies designed to directly boost immune cell function and improve immune surveillance in tissues.

Endothelial dysfunction in the kidney transplant population: Current evidence and management strategies

The endothelium modulates vascular homeostasis owing to a variety of vasoconstrictors and vasodilators. Endothelial dysfunction (ED), characterized by impaired vasodilation, inflammation, and thrombosis, triggers future cardiovascular (CV) diseases. Chronic kidney disease, a state of chronic inflammation caused by oxidative stress, metabolic abnormalities, infection, and uremic toxins damages the endothelium. ED is also associated with a decline in estimated glomerular filtration rate. After kidney transplantation, endothelial functions undergo immediate but partial restoration, promising graft longevity and enhanced CV health. However, the anticipated CV outcomes do not happen due to various transplant-related and unrelated risk factors for ED, culminating in poor CV health and graft survival. ED in kidney transplant recipients is an under-recognized and poorly studied entity. CV diseases are the leading cause of death among kidney transplant candidates with functioning grafts. ED contributes to the pathogenesis of many of the CV diseases. Various biomarkers and vasoreactivity tests are available to study endothelial functions. With an increasing number of transplants happening every year, and improved graft rejection rates due to the availability of effective immunosuppressants, the focus has now shifted to endothelial protection for the prevention, early recognition, and treatment of CV diseases.

Evaluating oxidative stress targeting treatments in in vitro models of placental stress relevant to preeclampsia

Background

Preeclampsia is a complex pregnancy disorder characterized by the new onset of hypertension and organ dysfunction, often leading to significant maternal and fetal morbidity and mortality. Placental dysfunction is a hallmark feature of preeclampsia, which is often caused by inappropriate trophoblast cell function in association with oxidative stress, inflammation and/or pathological hypoxia. This study explores the role of oxidative stress in trophoblast cell-based models mimicking the preeclamptic placenta and evaluates potential therapeutic strategies targeting these mechanisms.

Methods

Uric acid (UA) and malondialdehyde (MDA) concentrations were measured in human plasma from women with preeclampsia (n = 24) or normotensive controls (n = 14) using colorimetric assays. Custom-made first trimester trophoblast cell line, ACH-3P, was exposed to various preeclampsia-like stimuli including hypoxia mimetic (dimethyloxalylglycine or DMOG, 1 mM), inflammation (tumour necrosis factor or TNF-α, 10 ng/mL) or mitochondria dysfunction agent, (Rhodamine-6G or Rho-6G, 1 μg/mL), ± aspirin (0.5 mM), metformin (0.5 mM), AD-01 (100 nM) or resveratrol (15 µM), for 48 h. Following treatments, UA/MDA, proliferation (MTT), wound scratch and cytometric bead, assays, were performed.

Results

Overall, MDA plasma concentration was increased in the preeclampsia group compared to healthy controls (p < 0.001) whereas UA showed a trend towards an increase (p = 0.06); when adjusted for differences in gestational age at blood sampling, MDA remained (p < 0.001) whereas UA became (p = 0.03) significantly correlated with preeclampsia. Our 2D first trimester trophoblast cell-based in vitro model of placental stress as observed in preeclampsia, mimicked the increase in UA concentration following treatment with DMOG (p < 0.0001), TNF-α (p < 0.05) or Rho-6G (p < 0.001) whereas MDA cell concentration increased only in the presence of DMOG (p < 0.0001) or Rho-6G (p < 0.001). Metformin was able to abrogate DMOG- (p < 0.01), Rho-6G- (p < 0.0001) or TNF-α- (p < 0.01) induced increase in UA, or DMOG- (p < 0.0001) or TNF-α- (p < 0.05)induced increase in MDA. AD-01 abrogated UA or MDA increase in the presence of TNF-α (p < 0.001) or Rho-6G (p < 0.001)/DMOG (p < 0.0001), respectively. The preeclampsia-like stimuli also mimicked adverse impact on trophoblast cell proliferation, migration and inflammation, most of which were restored with either aspirin, metformin, resveratrol, or AD-01 (p < 0.05).

Conclusion

Our 2D in vitro models recapitulate the response of the first trimester trophoblast cells to preeclampsia-like stresses, modelling inappropriate placental development, and demonstrate therapeutic potential of repurposed treatments.

Panduratin A Inhibits TNF Alpha-Stimulated Endothelial Cell Activation Through Suppressing the NF-κB Pathway

Upon exposure to inflammatory stimuli including TNF-α, endothelial cells are activated leading to the adhesion of monocytes to their surface. These events are involved in the pathophysiology of atherosclerosis. Since TNF-α activates the NF-κB pathway, which contributes to atherosclerosis, targeting this signaling pathway may help prevent the risk of developing the disease. The current study elucidated the inhibitory effect of panduratin A (PA) on TNF-α-induced endothelial activation and monocyte adhesion. We discovered that PA reduced the level of pro-inflammatory cytokine IL-6 and chemokine MCP-1 in the media collected from endothelial cells stimulated with TNF-α. In addition, PA inhibited the expression of ICAM-1 and VCAM-1 on the surface of TNF-α-induced endothelial cells resulting in a decrease in the number of monocytes attached to endothelial cell surface. Mechanistically, PA prevented IκB degradation and specifically suppressed NF-κB phosphorylation and nuclear translocation in endothelial cells. However, PA had no inhibitory effect on the phosphorylation of AKT, ERK1/2, p38, and JNK. Taken together, PA blocked the production of cytokine and chemokine, adhesion molecules, and monocyte adhesion in response to TNF-α stimulation, in part, through NF-κB inhibition. Our study suggests that PA may possibly be effective in blocking the pathophysiology of atherosclerosis.

Metformin in Antiviral Therapy: Evidence and Perspectives

Metformin, a widely used antidiabetic medication, has emerged as a promising broad-spectrum antiviral agent due to its ability to modulate cellular pathways essential for viral replication. By activating AMPK, metformin depletes cellular energy reserves that viruses rely on, effectively limiting the replication of pathogens such as influenza, HIV, SARS-CoV-2, HBV, and HCV. Its role in inhibiting the mTOR pathway, crucial for viral protein synthesis and reactivation, is particularly significant in managing infections caused by HIV, CMV, and EBV. Furthermore, metformin reduces oxidative stress and reactive oxygen species (ROS), which are critical for replicating arboviruses such as Zika and dengue. The drug also regulates immune responses, cellular differentiation, and inflammation, disrupting the life cycle of HPV and potentially other viruses. These diverse mechanisms suppress viral replication, enhance immune system functionality, and contribute to better clinical outcomes. This multifaceted approach highlights metformin's potential as an adjunctive therapy in treating a wide range of viral infections.

Exploring the clinical connections between epilepsy and diabetes mellitus: Promising therapeutic strategies utilizing agmatine and metformin

PURPOSE

Diabetes mellitus (DM) and epilepsy and the psychological and socio-economic implications that are associated with their treatments can be quite perplexing. Metformin is an antihyperglycemic medication that is used to treat type 2 DM. In addition, metformin elicits protective actions against multiple diseases, including neurodegeneration and epilepsy. Recent studies indicate that metformin alters the resident gut microbiota in favor of species producing agmatine, an arginine metabolite which, in addition to beneficially altering metabolic pathways, is a potent neuroprotectant and neuromodulant.

METHODS

We first examine the literature for epidemiological and clinical evidences linking DM and epilepsy. Next, basing our analyses on published literature, we propose the possible complementarity of agmatine and metformin in the treatment of DM and epilepsy.

RESULTS

Our analyses of the clinical data suggest a significant association between pathogeneses of epilepsy and DM. Further, both agmatine and metformin appear to be multimodal therapeutic agents and have robust antiepileptogenic and antidiabetic properties. Data from animal and clinical studies largely support the use of metformin/agmatine as a double-edged pharmacotherapeutic agent against DM and epilepsy, particularly in their concurrent pathological occurrences.

CONCLUSION

The present review explores the evidences and available data on possible uses of metformin/agmatine as pertinent antidiabetic and antiepileptic agents. Our hope is that this will stimulate further research on the therapeutic actions of these multimodal agents, particularly for subject-specific clinical outcomes.

Angiotensin II Exposure In Vitro Reduces High Salt-Induced Reactive Oxygen Species Production and Modulates Cell Adhesion Molecules' Expression in Human Aortic Endothelial Cell Line

Background/Objectives: Increased sodium chloride (NaCl) intake led to leukocyte activation and impaired vasodilatation via increased oxidative stress in human/animal models. Interestingly, subpressor doses of angiotensin II (AngII) restored endothelium-dependent vascular reactivity, which was impaired in a high-salt (HS) diet in animal models. Therefore, the present study aimed to assess the effects of AngII exposure following high salt (HS) loading on endothelial cells' (ECs') viability, activation, and reactive oxygen species (ROS) production. Methods: The fifth passage of human aortic endothelial cells (HAECs) was cultured for 24, 48, and 72 h with NaCl, namely, the control (270 mOsmol/kg), HS320 (320 mOsmol/kg), and HS350 (350 mOsmol/kg). AngII was administered at the half-time of the NaCl incubation (10-4-10-7 mol/L). Results: The cell viability was significantly reduced after 24 h in the HS350 group and in all groups after longer incubation. AngII partly preserved the viability in the HAECs with shorter exposure and lower concentrations of NaCl. Intracellular hydrogen peroxide (H2O2) and peroxynitrite (ONOO-) significantly increased in the HS320 group following AngII exposure compared to the control, while it decreased in the HS350 group compared to the HS control. A significant decrease in superoxide anion (O2.-) formation was observed following AngII exposure at 10-5, 10-6, and 10-7 mol/L for both HS groups. There was a significant decrease in intracellular adhesion molecule 1 (ICAM-1) and endoglin expression in both groups following treatment with 10-4 and 10-5 mol/L of AngII. Conclusions: The results demonstrated that AngII significantly reduced ROS production at HS350 concentrations and modulated the viability, proliferation, and activation states in ECs.

Mechanistic insights into the regression of atherosclerotic plaques

Atherosclerosis is a major contributor to cardiovascular diseases and mortality globally. The progression of atherosclerotic disease results in the expansion of plaques and the development of necrotic cores. Subsequent plaque rupture can lead to thrombosis, occluding blood vessels, and end-organ ischemia with consequential ischemic injury. Atherosclerotic plaques are formed by the accumulation of lipid particles overloaded in the subendothelial layer of blood vessels. Abnormally elevated blood lipid levels and impaired endothelial function are the initial factors leading to atherosclerosis. The atherosclerosis research has never been interrupted, and the previous view was that the pathogenesis of atherosclerosis is an irreversible and chronic process. However, recent studies have found that the progression of atherosclerosis can be halted when patients' blood lipid levels are reversed to normal or lower. A large number of studies indicates that it can inhibit the progression of atherosclerosis lesions and promote the regression of atherosclerotic plaques and necrotic cores by lowering blood lipid levels, improving the repair ability of vascular endothelial cells, promoting the reverse cholesterol transport in plaque foam cells and enhancing the ability of macrophages to phagocytize and clear the necrotic core of plaque. This article reviews the progress of research on the mechanism of atherosclerotic plaque regression. Our goal is to provide guidance for developing better therapeutic approaches to atherosclerosis by reviewing and analyzing the latest scientific findings.

Metformin modulates microbiota and improves blood pressure and cardiac remodeling in a rat model of hypertension

AIMS

Metformin has been attributed to cardiovascular protection even in the absence of diabetes. Recent observations suggest that metformin influences the gut microbiome. We aimed to investigate the influence of metformin on the gut microbiota and hypertensive target organ damage in hypertensive rats.

METHODS

Male double transgenic rats overexpressing the human renin and angiotensinogen genes (dTGR), a model of angiotensin II-dependent hypertension, were treated with metformin (300 mg/kg/day) or vehicle from 4 to 7 weeks of age. We assessed gut microbiome composition and function using shotgun metagenomic sequencing and measured blood pressure via radiotelemetry. Cardiac and renal organ damage and inflammation were evaluated by echocardiography, histology, and flow cytometry.

RESULTS

Metformin treatment increased the production of short-chain fatty acids (SCFA) acetate and propionate in feces without altering microbial composition and diversity. It significantly reduced systolic and diastolic blood pressure and improved cardiac function, as measured by end-diastolic volume, E/A, and stroke volume despite increased cardiac hypertrophy. Metformin reduced cardiac inflammation by lowering macrophage infiltration and shifting macrophage subpopulations towards a less inflammatory phenotype. The observed improvements in blood pressure, cardiac function, and inflammation correlated with fecal SCFA levels in dTGR. In vitro, acetate and propionate altered M1-like gene expression in macrophages, reinforcing anti-inflammatory effects. Metformin did not affect hypertensive renal damage or microvascular structure.

CONCLUSION

Metformin modulated the gut microbiome, increased SCFA production, and ameliorated blood pressure and cardiac remodeling in dTGR. Our findings confirm the protective effects of metformin in the absence of diabetes, highlighting SCFA as a potential mediators.

Mechanisms of long COVID and the path toward therapeutics

Long COVID, a type of post-acute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (PASC) defined by medically unexplained symptoms following infection with SARS-CoV-2, is a newly recognized infection-associated chronic condition that causes disability in some people. Substantial progress has been made in defining its epidemiology, biology, and pathophysiology. However, there is no cure for the tens of millions of people believed to be experiencing long COVID, and industry engagement in developing therapeutics has been limited. Here, we review the current state of knowledge regarding the biology and pathophysiology of long COVID, focusing on how the proposed mechanisms explain the physiology of the syndrome and how they provide a rationale for the implementation of a broad experimental medicine and clinical trials agenda. Progress toward preventing and curing long COVID and other infection-associated chronic conditions will require deep and sustained investment by funders and industry.

SWATH-proteomics reveals Mathurameha, a traditional anti-diabetic herbal formula, attenuates high glucose-induced endothelial dysfunction through the EGF/NO/IL-1β regulatory axis

Mathurameha is a traditional Thai herbal formula with a clinically proven effect of blood sugar reduction in patients with diabetes mellitus, but its anti-diabetic complication potential is largely unknown. This study aimed to elucidate the effects of Mathurameha and its underlying mechanisms against high glucose-induced endothelial dysfunction in human endothelial EA.hy926 cells. After confirming no cytotoxic effects, the cells were treated with normal glucose (NG), high glucose (HG), or high glucose plus Mathurameha (HG + M) for 24 h. A quantitative label-free proteomic analysis using the sequential window acquisition of all theoretical mass spectra (SWATH-MS) approach identified 24 differentially altered proteins among the three groups: 7 between HG and NG, 9 between HG + M and NG, and 13 between HG + M and HG. Bioinformatic analyses suggested a potential anti-diabetic action through the epidermal growth factor (EGF) pathway. Subsequent functional validations demonstrated that Mathurameha reduced the EGF secretion and the intracellular reactive oxygen species (ROS) level in high glucose-treated cells. Mathurameha also exhibited a stimulatory effect on nitric oxide (NO) production while significantly reducing the secretion of endothelin-1 (ET-1) and interleukin-1β (IL-1β) in high glucose-treated cells. In conclusion, our findings demonstrated that Mathurameha attenuated high glucose-induced endothelial dysfunction through the EGF/NO/IL-1β regulatory axis. SIGNIFICANCE: This study reveals the potential of Mathurameha, a traditional Thai herbal formula, in mitigating high glucose-induced endothelial dysfunction, a common complication in diabetes mellitus. Using proteomics and bioinformatic analyses followed by functional validations, the present study highlights the protective effects of Mathurameha through the EGF/NO/IL-1β regulatory axis. These findings support its potential use as a therapeutic intervention for diabetic vascular complications and provide valuable information for developing more effective anti-diabetic drugs.

Investigation of the Dysfunction Caused by High Glucose, Advanced Glycation End Products, and Interleukin-1 Beta and the Effects of Therapeutic Agents on the Microphysiological Artery Model

Diabetes mellitus (DM) has substantial global implications and contributes to vascular inflammation and the onset of atherosclerotic cardiovascular diseases. However, translating the findings from animal models to humans has inherent limitations, necessitating a novel platform. Therefore, herein, an arterial model is established using a microphysiological system. This model successfully replicates the stratified characteristics of human arteries by integrating collagen, endothelial cells (ECs), and vascular smooth muscle cells (VSMCs). Perfusion via a peristaltic pump shows dynamic characteristics distinct from those of static culture models. High glucose, advanced glycation end products (AGEs), and interleukin-1 beta are employed to stimulate diabetic conditions, resulting in notable cellular changes and different levels of cytokines and nitric oxide. Additionally, the interactions between the disease models and oxidized low-density lipoproteins (LDL) are examined. Finally, the potential therapeutic effects of metformin, atorvastatin, and diphenyleneiodonium are investigated. Metformin and diphenyleneiodonium mitigate high-glucose- and AGE-associated pathological changes, whereas atorvastatin affects only the morphology of ECs. Altogether, the arterial model represents a pivotal advancement, offering a robust and insightful platform for investigating cardiovascular diseases and their corresponding drug development.

Metformin: Therapeutic profile in the treatment of type 2 diabetes

Metformin (dimethyl-biguanide) can claim its origins in the use of Galega officinalis as a plant treatment for symptoms ascribed to diabetes. Since the first clinical use of metformin as a glucose-lowering agent in 1957, this medicine has emerged as a first-line pharmacological option to support lifestyle interventions in the management of type 2 diabetes (T2D). It acts through multiple cellular pathways, principally in the gut, liver and muscle, to counter insulin resistance and lower blood glucose without weight gain or risk of overt hypoglycaemia. Other effects include improvements in lipid metabolism, decreased inflammation and lower long-term cardiovascular risk. Metformin is conveniently combined with other diabetes medications, can be prescribed in prediabetes to reduce the risk of progression to T2D, and is used in some regions to assist glycaemic control in pregnancy. Consistent with its diversity of actions, established safety profile and cost-effectiveness, metformin is being assessed for further possible clinical applications. The use of metformin requires adequate renal function for drug elimination, and may cause initial gastrointestinal side effects, which can be moderated by taking with meals or using an extended-release formulation. Thus, metformin serves as a valuable therapeutic resource for use throughout the natural history of T2D.

The potential therapeutic value of the natural plant compounds matrine and oxymatrine in cardiovascular diseases

Matrine (MT) and Oxymatrine (OMT) are two natural alkaloids derived from plants. These bioactive compounds are notable for their diverse pharmacological effects and have been extensively studied and recognized in the treatment of cardiovascular diseases in recent years. The cardioprotective effects of MT and OMT involve multiple aspects, primarily including antioxidative stress, anti-inflammatory actions, anti-atherosclerosis, restoration of vascular function, and inhibition of cardiac remodeling and failure. Clinical pharmacology research has identified numerous novel molecular mechanisms of OMT and MT, such as JAK/STAT, Nrf2/HO-1, PI3 K/AKT, TGF-β1/Smad, and Notch pathways, providing new evidence supporting their promising therapeutic potential against cardiovascular diseases. Thus, this review aims to investigate the potential applications of MT and OMT in treating cardiovascular diseases, encompassing their mechanisms, efficacy, and safety, confirming their promise as lead compounds in anti-cardiovascular disease drug development.

Insights into the Molecular Mechanism of Endothelial Glycocalyx Dysfunction during Heart Surgery

The endothelial glycocalyx (EGC) is a layer of proteoglycans (associated with glycosaminoglycans) and glycoproteins, which adsorbs plasma proteins on the luminal surface of endothelial cells. Its main function is to participate in separating the circulating blood from the inner layers of the vessels and the surrounding tissues. Physiologically, the EGC stimulates mechanotransduction, the endothelial charge, thrombocyte adhesion, leukocyte tissue recruitment, and molecule extravasation. Hence, severe impairment of the EGC has been implicated in various pathological conditions, including sepsis, diabetes, chronic kidney disease, inflammatory disorders, hypernatremia, hypervolemia, atherosclerosis, and ischemia/reperfusion injury. Moreover, alterations in EGC have been associated with altered responses to therapeutic interventions in conditions such as cardiovascular diseases. Investigation into the function of the glycocalyx has expanded knowledge about vascular disorders and indicated the need to consider new approaches in the treatment of severe endothelial dysfunction. This review aims to present the current understanding of the molecular mechanisms underlying cardiovascular diseases and to elucidate the impact of heart surgery on EGC dysfunction.

Metformin: A Dual-Role Player in Cancer Treatment and Prevention

Cancer continues to pose a significant global health challenge, as evidenced by the increasing incidence rates and high mortality rates, despite the advancements made in chemotherapy. The emergence of chemoresistance further complicates the effectiveness of treatment. However, there is growing interest in the potential of metformin, a commonly prescribed drug for type 2 diabetes mellitus (T2DM), as an adjuvant chemotherapy agent in cancer treatment. Although the precise mechanism of action of metformin in cancer therapy is not fully understood, it has been found to have pleiotropic effects, including the modulation of metabolic pathways, reduction in inflammation, and the regulation of cellular proliferation. This comprehensive review examines the anticancer properties of metformin, drawing insights from various studies conducted in vitro and in vivo, as well as from clinical trials and observational research. This review discusses the mechanisms of action involving both insulin-dependent and independent pathways, shedding light on the potential of metformin as a therapeutic agent for different types of cancer. Despite promising findings, there are challenges that need to be addressed, such as conflicting outcomes in clinical trials, considerations regarding dosing, and the development of resistance. These challenges highlight the importance of further research to fully harness the therapeutic potential of metformin in cancer treatment. The aims of this review are to provide a contemporary understanding of the role of metformin in cancer therapy and identify areas for future exploration in the pursuit of effective anticancer strategies.

Real-world risk of cardiovascular diseases in patients with type 2 diabetes associated with sodium-glucose cotransporter 2 inhibitors in comparison with metformin: A propensity score-matched model analysis in Japan

We aimed to compare the effects of cardiovascular disease risk in Japanese patients with type 2 diabetes on sodium-glucose cotransporter 2 inhibitors (SGLT2Is) or metformin. This retrospective, real-world cohort study was carried out using a claims database and propensity score matching; 58,402 eligible patients (29,201 per group) were included. The outcomes included nonfatal myocardial infarction, angina pectoris, nonfatal stroke, hospitalization for heart failure and composite end-points. The hazard ratio (HR) for the composite end-point was 0.79, which was lower for SGLT2Is than for metformin. For male patients (HR 0.76), patients aged <65 years (HR 0.94), patients aged ≥75 years (HR 0.78) and patients with body mass index ≥25 kg/m2 (HR 0.76), the HRs for the composite end-point were significantly lower in the SGLT2I group than in the metformin group. SGLT2Is might be superior to metformin in reducing the composite risk of cardiovascular disease in patients with type 2 diabetes.

Persistent endothelial dysfunction in post-COVID-19 syndrome and its associations with symptom severity and chronic inflammation

BACKGROUND

Post-COVID-19 syndrome (PCS) is a lingering disease with ongoing symptoms such as fatigue and cognitive impairment resulting in a high impact on the daily life of patients. Understanding the pathophysiology of PCS is a public health priority, as it still poses a diagnostic and treatment challenge for physicians.

METHODS

In this prospective observational cohort study, we analyzed the retinal microcirculation using Retinal Vessel Analysis (RVA) in a cohort of patients with PCS and compared it to an age- and gender-matched healthy cohort (n = 41, matched out of n = 204).

MEASUREMENTS AND MAIN RESULTS

PCS patients exhibit persistent endothelial dysfunction (ED), as indicated by significantly lower venular flicker-induced dilation (vFID; 3.42% ± 1.77% vs. 4.64% ± 2.59%; p = 0.02), narrower central retinal artery equivalent (CRAE; 178.1 [167.5-190.2] vs. 189.1 [179.4-197.2], p = 0.01) and lower arteriolar-venular ratio (AVR; (0.84 [0.8-0.9] vs. 0.88 [0.8-0.9], p = 0.007). When combining AVR and vFID, predicted scores reached good ability to discriminate groups (area under the curve: 0.75). Higher PCS severity scores correlated with lower AVR (R = - 0.37 p = 0.017). The association of microvascular changes with PCS severity were amplified in PCS patients exhibiting higher levels of inflammatory parameters.

CONCLUSION

Our results demonstrate that prolonged endothelial dysfunction is a hallmark of PCS, and impairments of the microcirculation seem to explain ongoing symptoms in patients. As potential therapies for PCS emerge, RVA parameters may become relevant as clinical biomarkers for diagnosis and therapy management.

TRIAL REGISTRATION

This study was previously registered at ClinicalTrials ("All Eyes on PCS-Analysis of the Retinal Microvasculature in Patients with Post-COVID-19 Syndrome". NCT05635552. https://clinicaltrials.gov/ct2/show/NCT05635552 ). Persistent endothelial dysfunction in post-COVID-19 syndrome. Acute SARS-CoV-2 infection indirectly or directly causes endotheliitis in patients. N = 41 PCS patients were recruited and retinal vessel analysis was performed to assess microvascular endothelial function. Images of SVA and DVA are illustrative for RVA data analysis. For each PCS patient and healthy cohort, venular vessel diameter of the three measurement cycles was calculated and plotted on a diameter-time curve. Patients exhibited reduced flicker-induced dilation in veins (vFID) measured by dynamic vessel analysis (DVA) and lower central retinal arteriolar equivalent (CRAE) and arteriolar-venular ratio (AVR) and a tendency towards higher central retinal venular equivalent (CRVE) when compared to SARS-CoV-2 infection naïve participants. Created with BioRender.com.

Metformin-mediated epigenetic modifications in diabetes and associated conditions: Biological and clinical relevance

An intricate interplay between genetic and environmental factors contributes to the development of type 2 diabetes (T2D) and its complications. Therefore, it is not surprising that the epigenome also plays a crucial role in the pathogenesis of T2D. Hyperglycemia can indeed trigger epigenetic modifications, thereby regulating different gene expression patterns. Such epigenetic changes can persist after normalizing serum glucose concentrations, suggesting the presence of a 'metabolic memory' of previous hyperglycemia which may also be epigenetically regulated. Metformin, a derivative of biguanide known to reduce serum glucose concentrations in patients with T2D, appears to exert additional pleiotropic effects that are mediated by multiple epigenetic modifications. Such modifications have been reported in various organs, tissues, and cellular compartments and appear to account for the effects of metformin on glycemic control as well as local and systemic inflammation, oxidant stress, and fibrosis. This review discusses the emerging evidence regarding the reported metformin-mediated epigenetic modifications, particularly on short and long non-coding RNAs, DNA methylation, and histone proteins post-translational modifications, their biological and clinical significance, potential therapeutic applications, and future research directions.

The Role of Polymorphism in the Endothelial Homeostasis and Vitamin D Metabolism Genes in the Severity of Coronary Artery Disease

Coronary artery disease (CAD) remains one of the leading causes of cardiovascular morbidity and mortality worldwide. The maintenance of endothelial homeostasis and vitamin D metabolism play an important role in CAD pathogenesis. This study aimed to determine the association of endothelial homeostasis and vitamin D metabolism gene polymorphism with CAD severity. A total of 224 low-risk patients (SYNTAX score ≤ 31) and 36 high-risk patients (SYNTAX score > 31) were recruited for this study. The serum level of E-, L- and P-selectins; endothelin; eNOS; 25OH; and 1.25-dihydroxy vitamin D was measured using an enzyme-linked immunosorbent assay (ELISA). Polymorphic variants in SELE, SELP, SELPLG, END1, NOS3, VDR and GC were analyzed using a polymerase chain reaction (PCR). We found no differences in the serum levels of the studied markers between high- and low-risk patients. Three polymorphic variants associated with CAD severity were discovered: END1 rs3087459, END1 rs5370 and GC rs2298849 in the log-additive model. Moreover, we discovered a significantly decreased serum level of 1.25-dihydroxy vitamin D in high-risk CAD patients with the A/A-A/G genotypes of the rs2228570 polymorphism of the VDR gene, the A/A genotype of the rs7041 polymorphism of the GC gene and the A/A genotype of the rs2298849 polymorphism of the GC gene.

Inflammatory Mediators of Endothelial Dysfunction

Endothelial dysfunction (ED) is characterized by imbalanced vasodilation and vasoconstriction, elevated reactive oxygen species (ROS), and inflammatory factors, as well as deficiency of nitric oxide (NO) bioavailability. It has been reported that the maintenance of endothelial cell integrity serves a significant role in human health and disease due to the involvement of the endothelium in several processes, such as regulation of vascular tone, regulation of hemostasis and thrombosis, cell adhesion, smooth muscle cell proliferation, and vascular inflammation. Inflammatory modulators/biomarkers, such as IL-1α, IL-1β, IL-6, IL-12, IL-15, IL-18, and tumor necrosis factor α, or alternative anti-inflammatory cytokine IL-10, and adhesion molecules (ICAM-1, VCAM-1), involved in atherosclerosis progression have been shown to predict cardiovascular diseases. Furthermore, several signaling pathways, such as NLRP3 inflammasome, that are associated with the inflammatory response and the disrupted H2S bioavailability are postulated to be new indicators for endothelial cell inflammation and its associated endothelial dysfunction. In this review, we summarize the knowledge of a plethora of reviews, research articles, and clinical trials concerning the key inflammatory modulators and signaling pathways in atherosclerosis due to endothelial dysfunction.

Endothelial Dysfunction in Patients Undergoing Cardiac Surgery: A Narrative Review and Clinical Implications

Cardiac surgery is one of the highest-risk procedures, usually involving cardiopulmonary bypass and commonly inducing endothelial injury that contributes to the development of perioperative and postoperative organ dysfunction. Substantial scientific efforts are being made to unravel the complex interaction of biomolecules involved in endothelial dysfunction to find new therapeutic targets and biomarkers and to develop therapeutic strategies to protect and restore the endothelium. This review highlights the current state-of-the-art knowledge on the structure and function of the endothelial glycocalyx and mechanisms of endothelial glycocalyx shedding in cardiac surgery. Particular emphasis is placed on potential strategies to protect and restore the endothelial glycocalyx in cardiac surgery. In addition, we have summarized and elaborated the latest evidence on conventional and potential biomarkers of endothelial dysfunction to provide a comprehensive synthesis of crucial mechanisms of endothelial dysfunction in patients undergoing cardiac surgery, and to highlight their clinical implications.

Influence of metformin on hyperandrogenism in women with polycystic ovary syndrome: a systematic review and meta-analysis of randomized clinical trials

PURPOSE

To summarize the effects of metformin treatment on markers of hyperandrogenism in patients diagnosed with polycystic ovary syndrome (PCOS).

METHODS

A systematic review, with meta-analysis, of randomized placebo-controlled clinical trials that evaluated the effects of metformin treatment in adult patients with PCOS on the levels of hyperandrogenism markers was conducted. The literature search, data extraction, risk of bias, and the assessment of certainty of evidence were performed independently by two reviewers using a structured form. The results were combined by applying the random effect, and the effect measure presented as a standardized mean difference (SMD). Significant values were considered as p < 0.05 with 95% CI. Furthermore, sensitivity analyses were performed in order to explore possible heterogeneity between studies.

RESULTS

Were included 18 studies in the quantitative evaluation and 17 studies (23 reports) in the quantitative evaluation. A significant reduction in total testosterone levels was seen in the metformin-treated group when compared to the control group after combining the results by the sensitivity analysis [SMD: - 0.46 (95% CI: - 0.89 to - 0.02)]. Therefore, FAI values were also regulated by metformin treatment.

CONCLUSION

We showed that metformin proved to be effective in reducing total testosterone levels, and the same was observed for free androgen index (FAI) values-a measure influenced by testosterone levels. The protocol of this study was registered at Prospero (CRD42021235761).

Gastrodin protects endothelial cells against high glucose-induced injury through up-regulation of PPARβ and alleviation of nitrative stress

In diabetes mellitus (DM), high glucose can result in endothelial cell injury, and then lead to diabetic vascular complications. Gastrodin, as the mainly components of Chinese traditional herb Tianma (Gastrodia elata Bl.), has been widely used for cardiovascular diseases. However, the known of the effect of gastrodin on endothelial cell injury is still limited. In this study, we aimed to investigate the effect and possible mechanism of gastrodin on high glucose-injured human umbilical vein endothelial cells (HUVEC). High glucose (30 mmol/L) treatment caused HUVEC injury. After gastrodin (0.1, 1, 10 μmol/L) treatment, compared with the high glucose group, the cell proliferation ability increased in a dose-dependent manner. Meanwhile, gastrodin (10 μmol/L) up-regulated the mRNA and protein expressions of PPARβ and eNOS, decreased the expressions of iNOS, also reduced the protein expression of 3-nitrotyrosine, and lowed the level of ONOO^-, increased NO content. Both the PPARβ antagonist GSK0660 (1 μmol/L) and the eNOS inhibitor L-NAME (10 μmol/L) were able to block the above effects of gastrodin. In conclusion, gastrodin protectes vascular endothelial cells from high glucose injury, which may be, at least partly, mediated by up-regulating the expression of PPARβ and negatively regulating nitrative stress.

Endothelial Autophagy Dysregulation in Diabetes

Diabetes mellitus is a major public health issue that affected 537 million people worldwide in 2021, a number that is only expected to increase in the upcoming decade. Diabetes is a systemic metabolic disease with devastating macro- and microvascular complications. Endothelial dysfunction is a key determinant in the pathogenesis of diabetes. Dysfunctional endothelium leads to vasoconstriction by decreased nitric oxide bioavailability and increased expression of vasoconstrictor factors, vascular inflammation through the production of pro-inflammatory cytokines, a loss of microvascular density leading to low organ perfusion, procoagulopathy, and/or arterial stiffening. Autophagy, a lysosomal recycling process, appears to play an important role in endothelial cells, ensuring endothelial homeostasis and functions. Previous reports have provided evidence of autophagic flux impairment in patients with type I or type II diabetes. In this review, we report evidence of endothelial autophagy dysfunction during diabetes. We discuss the mechanisms driving endothelial autophagic flux impairment and summarize therapeutic strategies targeting autophagy in diabetes.

Metformin effect on internal carotid artery blood flow assessed by area under the curve of carotid artery Doppler in women with polycystic ovarian syndrome

BACKGROUND

Insulin resistance (IR) was reported in most polycystic ovarian syndrome (PCOS) cases. Metformin, a biguanide drug, successfully reduced IR. Homeostatic Model Assessment for IR (HOMA-IR) and Doppler parameters assessed metformin's effectiveness.

AIM

To verify whether the area under the curve of the internal carotid artery (AUC-ICA) Doppler wave can be a useful marker for assessing IR among PCOS cases who presented with menstrual irregularity and were treated with metformin over 6 mo.

METHODS

An observational, cross-sectional study recruited 54 eligible PCOS women; the anthropometrics were as follows: age, body mass index (BMI), menstrual cycle days, biochemical serum cholesterol, low and high-density lipoprotein, sex hormone-binding globulin, fasting blood glucose, and HOMA-IR, hormonal testosterone, luteinizing hormone over follicle-stimulating hormone ratio, and ultrasonic pulsatility index (PI) and resistance index (RI), carotid artery intima-media thickness (CIMT) and (AUC-ICA) parameters were initially recorded and repeated 3 mo and 6 mo later with metformin tab 500 mg; three times/day for 6 mo. In addition, AUC-ICA was assessed by taking repeated systolic and diastolic wave height measurements.

RESULTS

Metformin caused a progressive reduction in BMI, menstrual cycle days, biochemical hormonal, and Doppler parameters (CIMT, PI, RI, and AUC-ICA). AUC-ICA correlated strongly to all PCOS parameters. AUC-ICA correlated inversely with treatment time (r = -0.98, P < 0.001) and positively with HOMA-IR (r = 0.98, P < 0.0001). Via the best subset regression model, the AUC-ICA had the highest predictive value for HOMA-IR.

CONCLUSION

AUC-ICA preceded PI, RI, and CIMT with a strong, meaningful correlation to all PCOS parameters, making it a reliable marker for the assessment of IR, especially during metformin therapy. Further studies are recommended to promote the application in practice.

Metformin protects against vascular calcification through the selective degradation of Runx2 by the p62 autophagy receptor

Vascular calcification is associated with aging, type 2 diabetes, and atherosclerosis, and increases the risk of cardiovascular morbidity and mortality. It is an active, highly regulated process that resembles physiological bone formation. It has previously been established that pharmacological doses of metformin alleviate arterial calcification through adenosine monophosphate-activated protein kinase (AMPK)-activated autophagy, however the specific pathway remains elusive. In the present study we hypothesized that metformin protects against arterial calcification through the direct autophagic degradation of runt-related transcription factor 2 (Runx2). Calcification was blunted in vascular smooth muscle cells (VSMCs) by metformin in a dose-dependent manner (0.5-1.5 mM) compared to control cells (p < 0.01). VSMCs cultured under high-phosphate (Pi) conditions in the presence of metformin (1 mM) showed a significant increase in LC3 puncta following bafilomycin-A1 (Baf-A; 5 nM) treatment compared to control cells (p < 0.001). Furthermore, reduced expression of Runx2 was observed in the nuclei of metformin-treated calcifying VSMCs (p < 0.0001). Evaluation of the functional role of autophagy through Atg3 knockdown in VSMCs showed aggravated Pi-induced calcification (p < 0.0001), failure to induce autophagy (punctate LC3) (p < 0.001) and increased nuclear Runx2 expression (p < 0.0001) in VSMCs cultured under high Pi conditions in the presence of metformin (1 mM). Mechanistic studies employing three-way coimmunoprecipitation with Runx2, p62, and LC3 revealed that p62 binds to both LC3 and Runx2 upon metformin treatment in VSMCs. Furthermore, immunoblotting with LC3 revealed that Runx2 specifically binds with p62 and LC3-II in metformin-treated calcified VSMCs. Lastly, we investigated the importance of the autophagy pathway in vascular calcification in a clinical setting. Ex vivo clinical analyses of calcified diabetic lower limb artery tissues highlighted a negative association between Runx2 and LC3 in the vascular calcification process. These studies suggest that exploitation of metformin and its analogues may represent a novel therapeutic strategy for clinical intervention through the induction of AMPK/Autophagy Related 3 (Atg3)-dependent autophagy and the subsequent p62-mediated autophagic degradation of Runx2.

Ginsenoside Rh1 protects human endothelial cells against lipopolysaccharide-induced inflammatory injury through inhibiting TLR2/4-mediated STAT3, NF-κB, and ER stress signaling pathways

AIM

Endothelial cell (EC) dysfunction initiates atherosclerosis by inducing inflammatory cytokines and adhesion molecules. Herein, we investigated the role of ginsenoside Rh1 (Rh1) in lipopolysaccharide (LPS)-induced EC dysfunction.

MAIN METHODS

The inhibitory effect of Rh1 on LPS binding to toll-like receptor 2 (TLR2) or TLR4 was evaluated using an immunofluorescence (IF) assay. Annexin V and cleaved caspase-3-positive EC apoptosis were evaluated by flow cytometry and IF assay. Western blotting and quantitative reverse transcription-PCR were performed to clarify underlying molecular mechanisms. In vivo model, effect of Rh1 on EC dysfunction was evaluated by using en face IF assay on aortas isolated C57BL/6 mice.

KEY FINDING

LPS (500 ng/mL) activated inflammatory signaling pathways, including ERK1/2, STAT3, and NF-κB. Interestingly, Rh1 significantly abolished the binding of LPS to TLR2 and TLR4. Consistently, Rh1 inhibited LPS-induced NF-κB activation and its downstream molecules, including inflammatory cytokines and adhesion molecules. Furthermore, Rh1 alleviated LPS-induced downregulation of eNOS promoter activity. Notably, inactivation of eNOS by 50 μM L-NAME significantly increased NF-κB promoter activity. In addition, Rh1 abolished LPS-mediated cell cycle arrest and EC apoptosis by inhibiting endoplasmic reticulum stress via PERK/CHOP/ERO1-α signaling pathway. Consistent with in vitro experimental data, Rh1 effectively suppressed LPS-induced VCAM-1 and CHOP expression and rescuing LPS-destroyed tight junctions between ECs as indicated in ZO-1 expression on mice aorta.

SIGNIFICANCE

Rh1 suppresses LPS-induced EC inflammation and apoptosis by inhibiting STAT3/NF-κB and endoplasmic reticulum stress signaling pathways, mediated by blocking LPS binding-to TLR2 and TLR4. Consistently, Rh1 effectively reduced EC dysfunction in vivo model.

Obesity induces extracellular vesicle release from the endothelium as a contributor to brain damage after cerebral ischemia in rats

OBJECTIVES

Cerebral ischemia is the most common cause of disability, the second most common cause of dementia, and the fourth most common cause of death in the developed world [Sveinsson OA, Kjartansson O, Valdimarsson EM. Heilablóðþurrð/heiladrep: Faraldsfræði, orsakir og einkenni [Cerebral ischemia/infarction - epidemiology, causes and symptoms]. Laeknabladid. 2014 May;100(5):271-9. Icelandic. doi:10.17992/lbl.2014.05.543]. Obesity has been associated with worse outcomes after ischemia in rats, triggering proinflammatory cytokine production related to the brain microvasculature. The way obesity triggers these effects remains mostly unknown. Therefore, the aim of this study was to elucidate the cellular mechanisms of damage triggered by obesity in the context of cerebral ischemia.

METHODS

We used a rat model of obesity induced by a 20% high fructose diet (HFD) and evaluated peripheral alterations in plasma (lipid and cytokine profiles). Then, we performed cerebral ischemia surgery using two-vessel occlusion (2VO) and analyzed neurological/motor performance and glial activation. Next, we treated endothelial cell line cultures with glutamate in vitro to simulate an excitotoxic environment, and we added 20% plasma from obese rats. Subsequently, we isolated EVs released from endothelial cells and treated primary cultures of astrocytes with them.

RESULTS

Rats fed a HFD had an increased BMI with dyslipidemia and high levels of proinflammatory cytokines. Glia from the obese rats exhibited altered morphology, suggesting hyperreactivity related to neurological and motor deficits. Plasma from obese rats induced activation of endothelial cells, increasing proinflammatory signals and releasing more EVs. Similarly, these EVs caused an increase in NF-κB and astrocyte cytotoxicity. Together, the results suggest that obesity activates proinflammatory signals in endothelial cells, resulting in the release of EVs that simultaneously contribute to astrocyte activation.

Metformin: Is it a drug for all reasons and diseases?

Metformin was first used to treat type 2 diabetes in the late 1950s and in 2022 remains the first-choice drug used daily by approximately 150 million people. An accumulation of positive pre-clinical and clinical data has stimulated interest in re-purposing metformin to treat a variety of diseases including COVID-19. In polycystic ovary syndrome metformin improves insulin sensitivity. In type 1 diabetes metformin may help reduce the insulin dose. Meta-analysis and data from pre-clinical and clinical studies link metformin to a reduction in the incidence of cancer. Clinical trials, including MILES (Metformin In Longevity Study), and TAME (Targeting Aging with Metformin), have been designed to determine if metformin can offset aging and extend lifespan. Pre-clinical and clinical data suggest that metformin, via suppression of pro-inflammatory pathways, protection of mitochondria and vascular function, and direct actions on neuronal stem cells, may protect against neurodegenerative diseases. Metformin has also been studied for its anti-bacterial, -viral, -malaria efficacy. Collectively, these data raise the question: Is metformin a drug for all diseases? It remains unclear as to whether all of these putative beneficial effects are secondary to its actions as an anti-hyperglycemic and insulin-sensitizing drug, or result from other cellular actions, including inhibition of mTOR (mammalian target for rapamycin), or direct anti-viral actions. Clarification is also sought as to whether data from ex vivo studies based on the use of high concentrations of metformin can be translated into clinical benefits, or whether they reflect a 'Paracelsus' effect. The environmental impact of metformin, a drug with no known metabolites, is another emerging issue that has been linked to endocrine disruption in fish, and extensive use in T2D has also raised concerns over effects on human reproduction. The objectives for this review are to: 1) evaluate the putative mechanism(s) of action of metformin; 2) analyze the controversial evidence for metformin's effectiveness in the treatment of diseases other than type 2 diabetes; 3) assess the reproducibility of the data, and finally 4) reach an informed conclusion as to whether metformin is a drug for all diseases and reasons. We conclude that the primary clinical benefits of metformin result from its insulin-sensitizing and antihyperglycaemic effects that secondarily contribute to a reduced risk of a number of diseases and thereby enhancing healthspan. However, benefits like improving vascular endothelial function that are independent of effects on glucose homeostasis add to metformin's therapeutic actions.

Metformin Alleviates LPS-Induced Acute Lung Injury by Regulating the SIRT1/NF-κB/NLRP3 Pathway and Inhibiting Endothelial Cell Pyroptosis

Acute respiratory distress syndrome (ARDS), a devastating complication of numerous conditions, is often associated with high mortality. It is well known that endothelial cell (EC) damage and inflammation are vital processes in the pathogenesis of ARDS. Nevertheless, the mechanisms of EC damage are largely unknown. In the present study, we investigated the role of pyroptosis in the initiation of ARDS and demonstrated that endothelial pyroptosis might play a pivotal role in the pathophysiology of ARDS. Metformin, an antidiabetic drug, exhibited a protective effect in lipopolysaccharide (LPS)-induced lung injury, and we hypothesized that metformin alleviated LPS-induced lung injury via inhibiting ECs pyroptosis. In vivo, male ICR mice were intratracheally injected with LPS, and metformin was previously administered intraperitoneally. Morphological properties of lung tissues were detected. We showed that metformin inhibited NLRP3 inflammasome activation and NLRP3-stimulated pyroptosis induction, as shown by decreased levels of cleaved caspase-1, N-terminal fragment of GSDMD, and protein contents of IL-1β in lung tissues of mice exposed to LPS. LPS-induced expression of vascular adhesion molecules was also reduced after the treatment with metformin. In vitro, exposure of pulmonary ECs to LPS resulted in increased expression of NLRP3 and pyroptosis-associated indicators. By inhibiting the expression of NLRP3 with NLRP3 inhibitor MCC950, pyroptosis-related markers and vascular adhesion molecules were ameliorated. Moreover, metformin treatment significantly inhibited the NF-κB signaling pathway and increased the expression of sirtuin 1 (SIRT1) both in LPS-stimulated lung tissues and pulmonary ECs. Administration of the selective SIRT1 inhibitor nicotinamide significantly reversed the protective effect of metformin against endothelial pyroptosis and lung injury in LPS-treated ECs and LPS-induced acute lung injury (ALI). Thus, these findings demonstrated that metformin alleviated LPS-induced ALI by inhibiting NF-κB-NLRP3–mediated ECs pyroptosis, possibly by upregulating the expression of SIRT1.

Targeting Peptide, Fluorescent Reagent Modified Magnetic Liposomes Coated with Rapamycin Target Early Atherosclerotic Plaque and Therapy

Atherosclerosis is the leading cause of global morbidity and mortality. Its therapy requires research in several areas, such as diagnosis of early arteriosclerosis, improvement of the pharmacokinetics and bioavailability of rapamycin as its therapeutic agents. Here, we used the targeting peptide VHPKQHR (VHP) (or fluorescent reagent) to modify the phospholipid molecules to target vascular cell adhesion molecule-1 (VCAM-1) and loaded ultrasmall paramagnetic iron oxide (USPIO/Fe3O4) plus rapamycin (Rap) to Rap/Fe3O4@VHP-Lipo (VHPKQHR-modified magnetic liposomes coated with Rap). This nanoparticle can be used for both the diagnosis and therapy of early atherosclerosis. We designed both an ex vivo system with mouse aortic endothelial cells (MAECs) and an in vivo system with ApoE knockout mice to test the labeling and delivering potential of Rap/Fe3O4@VHP-Lipo with fluorescent microscopy, flow cytometry and MRI. Our results of MRI imaging and fluorescence imaging showed that the T2 relaxation time of the Rap/Fe3O4@VHP-Lipo group was reduced by 2.7 times and 1.5 times, and the fluorescence intensity increased by 3.4 times and 2.5 times, respectively, compared with the normal saline group and the control liposome treatment group. It showed that Rap/Fe3O4@VHP-Lipo realized the diagnosis of early AS. Additionally, our results showed that, compared with the normal saline and control liposomes treatment group, the aortic fluorescence intensity of the Rap/Fe3O4@VHP-Lipo treatment group was significantly weaker, and the T2 relaxation time was prolonged by 8.9 times and 2.0 times, indicating that the targeted diagnostic agent detected the least plaques in the Rap/Fe3O4@VHP-Lipo treatment group. Based on our results, the synthesized theragnostic Rap/Fe3O4@VHP-Lipo serves as a great label for both MRI and fluorescence bimodal imaging of atherosclerosis. It also has therapeutic effects for the early treatment of atherosclerosis, and it has great potential for early diagnosis and can achieve the same level of therapy with a lower dose of Rap.

Mechanisms and Clinical Implications of Endothelial Dysfunction in Arterial Hypertension

The endothelium is composed of a monolayer of endothelial cells, lining the interior surface of blood and lymphatic vessels. Endothelial cells display important homeostatic functions, since they are able to respond to humoral and hemodynamic stimuli. Thus, endothelial dysfunction has been proposed as a key and early pathogenic mechanism in many clinical conditions. Given the relevant repercussions on cardiovascular risk, the complex interplay between endothelial dysfunction and systemic arterial hypertension has been a matter of study in recent years. Numerous articles have been published on this issue, all of which contribute to providing an interesting insight into the molecular mechanisms of endothelial dysfunction in arterial hypertension and its role as a biomarker of inflammation, oxidative stress, and vascular disease. The prognostic and therapeutic implications of endothelial dysfunction have also been analyzed in this clinical setting, with interesting new findings and potential applications in clinical practice and future research. The aim of this review is to summarize the pathophysiology of the relationship between endothelial dysfunction and systemic arterial hypertension, with a focus on the personalized pharmacological and rehabilitation strategies targeting endothelial dysfunction while treating hypertension and cardiovascular comorbidities.

Metformin Protects against Diabetic Cardiomyopathy: An Association between Desmin-Sarcomere Injury and the iNOS/mTOR/TIMP-1 Fibrosis Axis

The intermediate filament protein desmin is essential for maintaining the structural integrity of sarcomeres, the fundamental unit of cardiac muscle. Diabetes mellitus (DM) can cause desmin to become dysregulated, following episodes of nitrosative stress, through the activation of the iNOS/mTOR/TIMP-1 pathway, thereby stimulating collagen deposition in the myocardium. In this study, type 2 diabetes mellitus (T2DM) was induced in rats. One group of animals was pre-treated with metformin (200 mg/kg) prior to diabetes induction and subsequently kept on metformin until sacrifice at week 12. Cardiac injuries developed in the diabetic rats as demonstrated by a significant (p < 0.0001) inhibition of desmin immunostaining, profound sarcomere ultrastructural alterations, substantial damage to the left ventricular tissue, collagen deposition, and abnormal ECG recordings. DM also significantly induced the cardiac expression of inducible nitric oxide synthase (iNOS), mammalian target of rapamycin (mTOR), and the profibrogenic biomarker tissue inhibitor of metalloproteinase-1 (TIMP-1). The expression of all these markers was significantly inhibited by metformin. In addition, a significant (p < 0.0001) correlation between desmin tissue levels/sarcomere damage and glycated hemoglobin, heart rate, iNOS, mTOR, and fibrosis was observed. These findings demonstrate an association between damage of the cardiac contractile unit—desmin and sarcomere—and the iNOS/mTOR/TIMP-1/collagen axis of fibrosis in T2DM-induced cardiomyopathy, with metformin exhibiting beneficial cardiovascular pleiotropic effects.

Advances in the Role of Endothelial Cells in Cerebral Small Vessel Disease

Cerebral small vessel disease (CSVD) poses a serious socio-economic burden due to its high prevalence and severe impact on the quality of life of elderly patients. Pathological changes in CSVD mainly influence small cerebral arteries, microarteries, capillaries, and small veins, which are usually caused by multiple vascular risk factors. CSVD is often identified on brain magnetic resonance imaging (MRI) by recent small subcortical infarcts, white matter hyperintensities, lacune, cerebral microbleeds (CMBs), enlarged perivascular spaces (ePVSs), and brain atrophy. Endothelial cell (EC) dysfunction is earlier than clinical symptoms. Immune activation, inflammation, and oxidative stress may be potential mechanisms of EC injury. ECs of the blood–brain–barrier (BBB) are the most important part of the neurovascular unit (NVU) that ensures constant blood flow to the brain. Impaired cerebral vascular autoregulation and disrupted BBB cause cumulative brain damage. This review will focus on the role of EC injury in CSVD. Furthermore, several specific biomarkers will be discussed, which may be useful for us to assess the endothelial dysfunction and explore new therapeutic directions.

Endothelial Dysfunction and Cardiovascular Risk in Obstructive Sleep Apnea: A Review Article

Obstructive sleep apnea (OSA) is a respiratory condition during sleep caused by repeated pauses in breathing due to upper airway obstruction. It is estimated that OSA affects 30% of the population, but only 10% are well diagnosed due to the absence of a well-defined symptomatology and poor screening tools for early diagnosis. OSA is associated to an endothelial dysfunction inducing several biological responses such as hypoxia, hypercapnia and oxidative stress, among others. OSA also triggers respiratory, nervous, metabolic, humoral and immunity system activations that increase the possibility of suffering a cardiovascular (CV) disease. In this review, we expose different studies that show the relationship between OSA and endothelial dysfunction and its association with CV pathologies like hypertension, and we define the most well-known treatments and their limitations. Additionally, we describe the potential future directions in OSA research, and we report clinical features such as endothelial progenitor cell alterations that could act as biomarkers for the development of new diagnostic tools and target therapies.

A Clinical Perspective of the Multifaceted Mechanism of Metformin in Diabetes, Infections, Cognitive Dysfunction, and Cancer

In type 2 diabetes, ecological and lifecourse factors may interact with the host microbiota to influence expression of his/her genomes causing perturbation of interconnecting biological pathways with diverse clinical course. Metformin is a plant-based or plant-derived medicinal product used for the treatment of type 2 diabetes for over 60 years and is an essential drug listed by the World Health Organization. By reducing mitochondrial oxidative phosphorylation and adenosine triphosphate (ATP) production, metformin increased AMP (adenosine monophosphate)-activated protein kinase (AMPK) activity and altered cellular redox state with reduced glucagon activity, endogenous glucose production, lipogenesis, and protein synthesis. Metformin modulated immune response by directly reducing neutrophil to lymphocyte ratio and improving the phagocytic function of immune cells. By increasing the relative abundance of mucin-producing and short-chain-fatty-acid-producing gut microbes, metformin further improved the host inflammatory and metabolic milieu. Experimentally, metformin promoted apoptosis and reduced proliferation of cancer cells by reducing their oxygen consumption and modulating the microenvironment. Both clinical and mechanistic studies support the pluripotent effects of metformin on reducing cardiovascular–renal events, infection, cancer, cognitive dysfunction, and all-cause death in type 2 diabetes, making this low-cost medication a fundamental therapy for individualization of other glucose-lowering drugs in type 2 diabetes. Further research into the effects of metformin on cognitive function, infection and cancer, especially in people without diabetes, will provide new insights into the therapeutic value of metformin in our pursuit of prevention and treatment of ageing-related as well as acute and chronic diseases beyond diabetes.

Association of Metformin Use With Risk of Venous Thromboembolism in Adults With Type 2 Diabetes: A General-Population-Based Cohort Study

Metformin is hypothesized to protect against the risk of venous thromboembolism (VTE); however, there is a paucity of data supporting this hypothesis. Among individuals aged 40-90 years with a diagnosis of type 2 diabetes in the Health Improvement Network database (2000-2019), we compared the risks of incident VTE, pulmonary embolism, and deep vein thrombosis among metformin initiators with those among sulfonylurea initiators. Individuals were followed from their first prescription refill to an incident VTE, drug discontinuation, switching or augmenting, plan disenrollment, or the end of the study, whichever occurred first. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using the Cox model, adjusting for confounders using inverse probability of treatment weighting. Among 117,472 initiators of metformin and 13,835 initiators of sulfonylureas, 555 (1.3/1,000 person-years) and 75 (2.1/1,000 person-years) VTE cases occurred in each group, respectively. The multivariable-adjusted HR was 0.65 (95% CI: 0.51, 0.84). The corresponding risks for pulmonary embolism (adjusted HR = 0.71, 95% CI: 0.50, 1.01) and deep vein thrombosis (adjusted HR = 0.64, 95% CI: 0.48, 0.87) were also lower in metformin initiators than in sulfonylurea initiators. Our study provided empirical evidence to support a lower risk of VTE after initiation of metformin as compared with sulfonylureas among patients with type 2 diabetes.

Changes in biomarkers of endothelial function in the blood after intracerebral hemorrhage in rats with type 2 diabetes mellitus

Clinical evidence suggests that type 2 diabetes mellitus can increase the risk of intracerebral hemorrhage and provocation of neurodegeneration. This study was aimed at evaluating biomarkers of glycemic control, lipid profile, oxidative modification of proteins, as well as the functional state of endothelium in Wistar rats with type 2 diabetes mellitus complicated by intracerebral hemorrhage. Experimental type 2 diabetes mellitus was induced by intraperitoneal injection of streptozotocin (65 mg/kg) and nicotinamide (230 mg/kg). The intracerebral hemorrhage was induced by microinjection of sterile saline containing 0.2 IU bacterial collagenase into the striatum. Assessed biomarkers included the area under glycemic curve, glycated hemoglobin, total cholesterol, triglyceride, high-density lipoprotein, advanced glycation end products, markers of oxidative modification of proteins – aldehyde- and ketonephenylhydrazones, and markers of endothelial dysfunction – homocysteine, endothelin-1, von Willebrand factor and asymmetric dimethylarginine in blood serum. Both rats with type 2 diabetes mellitus and rats with intracerebral hemorrhage and diabetes had a significant elevated glycemic control as compared to intact animals. But combined pathology was additionally characterized by an impairment of lipid profile (increased triglyceride level and decreased as total cholesterol and high-density lipoprotein) resulting in a rise in the atherogenic index of plasma. A significant increase in the content of the markers of oxidative modification of proteins was observed in both experimental groups. But the rats with intracerebral hemorrhage and diabetes only had higher levels of advanced glycation end products in comparison with intact animals. The highest levels of endothelin-1, as a biomarker of endothelial dysfunction, were observed in animals with intracerebral hemorrhage and diabetes. Homocysteine and von Willebrand factor were elevated in rats with type 2 diabetes mellitus, while acute intracerebral hemorrhage did not potentiate the further growth in its levels. Such effect was not accompanied by a marked increase of asymmetric dimethylarginine level in blood serum, although there was a clear trend. In conclusion, the development of intracerebral hemorrhage in rats with type 2 diabetes mellitus can intensify the manifestations of oxidative stress, worsen lipid profile, and aggravate endothelial dysfunction. In this case, the pathological process may have the character of a “vicious circle”.

Metformin Prevents Hyperglycemia-Associated, Oxidative Stress-Induced Vascular Endothelial Dysfunction: Essential Role for the Orphan Nuclear Receptor Human Nuclear Receptor 4A1 (Nur77)

Vascular pathology is increased in diabetes because of reactive-oxygen-species (ROS)-induced endothelial cell damage. We found that in vitro and in a streptozotocin diabetes model in vivo, metformin at diabetes-therapeutic concentrations (1-50 µM) protects tissue-intact and cultured vascular endothelial cells from hyperglycemia/ROS-induced dysfunction typified by reduced agonist-stimulated endothelium-dependent, nitric oxide-mediated vasorelaxation in response to muscarinic or proteinase-activated-receptor 2 agonists. Metformin not only attenuated hyperglycemia-induced ROS production in aorta-derived endothelial cell cultures but also prevented hyperglycemia-induced endothelial mitochondrial dysfunction (reduced oxygen consumption rate). These endothelium-protective effects of metformin were absent in orphan-nuclear-receptor Nr4a1-null murine aorta tissues in accord with our observing a direct metformin-Nr4a1 interaction. Using in silico modeling of metformin-NR4A1 interactions, Nr4a1-mutagenesis, and a transfected human embryonic kidney 293T cell functional assay for metformin-activated Nr4a1, we identified two Nr4a1 prolines, P505/P549 (mouse sequences corresponding to human P501/P546), as key residues for enabling metformin to affect mitochondrial function. Our data indicate a critical role for Nr4a1 in metformin's endothelial-protective effects observed at micromolar concentrations, which activate AMPKinase but do not affect mitochondrial complex-I or complex-III oxygen consumption rates, as does 0.5 mM metformin. Thus, therapeutic metformin concentrations requiring the expression of Nr4a1 protect the vasculature from hyperglycemia-induced dysfunction in addition to metformin's action to enhance insulin action in patients with diabetes. SIGNIFICANCE STATEMENT: Metformin improves diabetic vasodilator function, having cardioprotective effects beyond glycemic control, but its mechanism to do so is unknown. We found that metformin at therapeutic concentrations (1-50µM) prevents hyperglycemia-induced endothelial dysfunction by attenuating reactive oxygen species-induced damage, whereas high metformin (>250 µM) impairs vascular function. However, metformin's action requires the expression of the orphan nuclear receptor NR4A1/Nur77. Our data reveal a novel mechanism whereby metformin preserves diabetic vascular endothelial function, with implications for developing new metformin-related therapeutic agents.

The association between chronic stress, hair cortisol, and angiographically documented coronary atherosclerosis, a case-control study

Cardiovascular diseases remain the principal contributor to global mortality and morbidity. Chronic stress has emerged as a strong prognostic factor for cardiovascular diseases. We aimed to measure hair cortisol concentration (HCC) in patients with angiographically confirmed coronary atherosclerosis and find the association between HCC and classic cardiovascular risk factors in a case-control study. The study included 500 angiographically confirmed coronary atherosclerosis patients and 500 age and sex-matched controls having no coronary stenosis. Hair cortisol concentration was assessed from a single sample of scalp hair by ELISA. Perceived stress scale 10 was used to evaluate the stress level of the participants. Spearman rank correlation was applied to find the association between hair cortisol level and classic cardiovascular risk factors. Multivariate regression was executed to assess the independent contribution of hair cortisol concentration as a coronary atherosclerosis risk factor. Median hair cortisol concentration was significantly high in patients with angiographically documented coronary atherosclerosis compared to controls (158(17.6-1331.3) pg/mg versus 73 (13.4-889) pg/mg. Hair cortisol concentration showed a significant positive correlation with BMI r = 525 and Hb1Ac r = 665 (both, p = ≤0.0001). In multivariate logistic regression analysis after adjusting for all the confounding variables, HCC, matched odds ratio (MOR), 10.73;95%CI (1.60,42.09) p-value = 0.001 remained the most significant predictor of coronary atherosclerosis.LAY SUMMARYHair cortisol concentrations (HCC) were significantly high in patients with angiographically confirmed coronary atherosclerosis compared to controls. HCC showed a significant positive correlation with diabetes and obesity and remained a major predictor of coronary atherosclerosis in the final analysis.

Cognitive Impairment in Frail Hypertensive Elderly Patients: Role of Hyperglycemia

Endothelial dysfunction is a key hallmark of hypertension, which is a leading risk factor for cognitive decline in older adults with or without frailty. Similarly, hyperglycemia is known to impair endothelial function and is a predictor of severe cardiovascular outcomes, independent of the presence of diabetes. On these grounds, we designed a study to assess the effects of high-glucose and metformin on brain microvascular endothelial cells (ECs) and on cognitive impairment in frail hypertensive patients. We tested the effects of metformin on high-glucose-induced cell death, cell permeability, and generation of reactive oxygen species in vitro, in human brain microvascular ECs. To investigate the consequences of hyperglycemia and metformin in the clinical scenario, we recruited frail hypertensive patients and we evaluated their Montreal Cognitive Assessment (MoCA) scores, comparing them according to the glycemic status (normoglycemic vs. hyperglycemic) and the use of metformin. We enrolled 376 patients, of which 209 successfully completed the study. We observed a significant correlation between MoCA score and glycemia. We found that hyperglycemic patients treated with metformin had a significantly better MoCA score than hyperglycemic patients treated with insulin (18.32 ± 3.9 vs. 14.94 ± 3.8; p < 0.001). Our in vitro assays confirmed the beneficial effects of metformin on human brain microvascular ECs. To our knowledge, this is the first study correlating MoCA score and glycemia in frail and hypertensive older adults, showing that hyperglycemia aggravates cognitive impairment.

CARDIOVASCULAR EFFECTS OF NON-INSULIN GLUCOSE-LOWERING AGENTS: A COMPREHENSIVE REVIEW OF TRIAL EVIDENCE AND POTENTIAL CARDIOPROTECTIVE MECHANISMS

Type 2 diabetes mellitus (T2DM) is highly prevalent and associated with a 2-fold increased mortality, mostly explained by cardiovascular diseases. Trial evidence on older glucose-lowering agents such as metformin and sulfonylureas is limited in terms of cardiovascular efficacy. Since 2008, after rosiglitazone was observed to increase the risk of myocardial infarction and heart failure (HF), cardiovascular outcome trials (CVOT) have been required by regulators for licensing new glucose-lowering agents. In the following CVOTs, dipeptidyl peptidase 4 inhibitors (DPP4i) have been shown to be safe but not to improve morbidity/mortality, except for saxagliptin which increased the risk of HF. Several glucagon-like peptide-1 receptor agonists (GLP1-Ra) and sodium-glucose cotransporter-2 inhibitors (SGLT2i) have been demonstrated to reduce the risk of cardiovascular morbidity and mortality. SGLT2i have shown a class effect for the reduction in risk of HF events in patients with T2DM, leading to trials testing their efficacy/safety in HF regardless of T2DM. In the DAPA-HF and the EMPEROR-Reduced trials dapagliflozin and empagliflozin, respectively, improved cardiovascular mortality/morbidity in patients with HF and reduced ejection fraction (HFrEF), with and without T2DM. Therefore, these drugs are now key part of HFrEF pharmacotherapy. In the SOLOIST-WHF, sotagliflozin reduced cardiovascular mortality/morbidity in patients with T2DM and a recent acute episode of HF regardless of EF. The DELIVER and the EMPEROR-Preserved are testing dapagliflozin and empagliflozin, respectively, in patients with HF with mildly reduced and preserved EF. A strong renal protective role of SGLT2i has also emerged in trials enrolling patients with and without T2DM.

Renal Delivery of Pharmacologic Agents During Machine Perfusion to Prevent Ischaemia-Reperfusion Injury: From Murine Model to Clinical Trials

Donor organ shortage still remains a serious obstacle for the access of wait-list patients to kidney transplantation, the best treatment for End-Stage Kidney Disease (ESKD). To expand the number of transplants, the use of lower quality organs from older ECD or DCD donors has become an established routine but at the price of increased incidence of Primary Non-Function, Delay Graft Function and lower-long term graft survival. In the last years, several improvements have been made in the field of renal transplantation from surgical procedure to preservation strategies. To improve renal outcomes, research has focused on development of innovative and dynamic preservation techniques, in order to assess graft function and promote regeneration by pharmacological intervention before transplantation. This review provides an overview of the current knowledge of these new preservation strategies by machine perfusions and pharmacological interventions at different timing possibilities: in the organ donor, ex-vivo during perfusion machine reconditioning or after implementation in the recipient. We will report therapies as anti-oxidant and anti-inflammatory agents, senolytics agents, complement inhibitors, HDL, siRNA and H2S supplementation. Renal delivery of pharmacologic agents during preservation state provides a window of opportunity to treat the organ in an isolated manner and a crucial route of administration. Even if few studies have been reported of transplantation after ex-vivo drugs administration, targeting the biological pathway associated to kidney failure (i.e. oxidative stress, complement system, fibrosis) might be a promising therapeutic strategy to improve the quality of various donor organs and expand organ availability.

Metformin alleviates monoamine oxidase-related vascular oxidative stress and endothelial dysfunction in rats with diet-induced obesity

In the past decade, monoamine oxidase (MAO) with 2 isoforms, MAO-A and B, has emerged as an important source of mitochondrial reactive oxygen species (ROS) in cardio-metabolic pathologies. We have previously reported that MAO-related oxidative stress mediates endothelial dysfunction in rodent models of diabetes and diabetic patients; however, the role of MAO in the vascular impairment associated to obesity has not been investigated so far. Metformin (METF), the first-line drug in the therapy of type 2 diabetes mellitus, has been reported to elicit vasculoprotective effects via partially elucidated mechanisms. The present study was purported to assess the effects of METF on MAO expression, ROS production and vasomotor function of aortas isolated from rats with diet-induced obesity. After 24 weeks of high calorie junk food (HCJF) diet, isolated aortic rings were prepared and treated with METF (10 μM, 12 h incubation). Measurements of MAO expression (quantitative PCR and immune histochemistry), ROS production (spectrometry and immune-fluorescence) and vascular reactivity (myograph studies) were performed in rat aortic rings. MAO expression was upregulated in aortic rings isolated from obese rats together with an increase in ROS production and an impairment of vascular reactivity. METF decreased MAO expression and ROS generation, reduced vascular contractility and improved the endothelium-dependent relaxation in the diseased vascular preparations. In conclusion, METF elicited vascular protective effects via the mitigation of MAO-related oxidative stress in the rat model of diet-induced obesity.

Endothelial Dysfunction in Atherosclerotic Cardiovascular Diseases and Beyond: From Mechanism to Pharmacotherapies

The endothelium, a cellular monolayer lining the blood vessel wall, plays a critical role in maintaining multiorgan health and homeostasis. Endothelial functions in health include dynamic maintenance of vascular tone, angiogenesis, hemostasis, and the provision of an antioxidant, anti-inflammatory, and antithrombotic interface. Dysfunction of the vascular endothelium presents with impaired endothelium-dependent vasodilation, heightened oxidative stress, chronic inflammation, leukocyte adhesion and hyperpermeability, and endothelial cell senescence. Recent studies have implicated altered endothelial cell metabolism and endothelial-to-mesenchymal transition as new features of endothelial dysfunction. Endothelial dysfunction is regarded as a hallmark of many diverse human panvascular diseases, including atherosclerosis, hypertension, and diabetes. Endothelial dysfunction has also been implicated in severe coronavirus disease 2019. Many clinically used pharmacotherapies, ranging from traditional lipid-lowering drugs, antihypertensive drugs, and antidiabetic drugs to proprotein convertase subtilisin/kexin type 9 inhibitors and interleukin 1β monoclonal antibodies, counter endothelial dysfunction as part of their clinical benefits. The regulation of endothelial dysfunction by noncoding RNAs has provided novel insights into these newly described regulators of endothelial dysfunction, thus yielding potential new therapeutic approaches. Altogether, a better understanding of the versatile (dys)functions of endothelial cells will not only deepen our comprehension of human diseases but also accelerate effective therapeutic drug discovery. In this review, we provide a timely overview of the multiple layers of endothelial function, describe the consequences and mechanisms of endothelial dysfunction, and identify pathways to effective targeted therapies. SIGNIFICANCE STATEMENT: The endothelium was initially considered to be a semipermeable biomechanical barrier and gatekeeper of vascular health. In recent decades, a deepened understanding of the biological functions of the endothelium has led to its recognition as a ubiquitous tissue regulating vascular tone, cell behavior, innate immunity, cell-cell interactions, and cell metabolism in the vessel wall. Endothelial dysfunction is the hallmark of cardiovascular, metabolic, and emerging infectious diseases. Pharmacotherapies targeting endothelial dysfunction have potential for treatment of cardiovascular and many other diseases.

A novel human arterial wall-on-a-chip to study endothelial inflammation and vascular smooth muscle cell migration in early atherosclerosis

Mechanistic understanding of atherosclerosis is largely hampered by the lack of a suitable in vitro human arterial model that recapitulates the arterial wall structure, and the interplay between different cell types and the surrounding extracellular matrix (ECM). This work introduces a novel microfluidic endothelial cell (EC)-smooth muscle cell (SMC) 3D co-culture platform that replicates the structural and biological aspects of the human arterial wall for modeling early atherosclerosis. Using a modified surface tension-based ECM patterning method, we established a well-defined intima-media-like structure, and identified an ECM composition (collagen I and Matrigel mixture) that retains the SMCs in a quiescent and aligned state, characteristic of a healthy artery. Endothelial stimulation with cytokines (IL-1β and TNFα) and oxidized low-density lipoprotein (oxLDL) was performed on-chip to study various early atherogenic events including endothelial inflammation (ICAM-1 expression), EC/SMC oxLDL uptake, SMC migration, and monocyte-EC adhesion. As a proof-of-concept for drug screening applications, we demonstrated the atheroprotective effects of vitamin D (1,25(OH)2D3) and metformin in mitigating cytokine-induced monocyte-EC adhesion and SMC migration. Overall, the developed arterial wall model facilitates quantitative and multi-factorial studies of EC and SMC phenotype in an atherogenic environment, and can be readily used as a platform technology to reconstitute multi-layered ECM tissue biointerfaces.