Uncovering the link between diabetes and cardiovascular diseases: insights from adipose-derived stem cells.

Cardiovascular diseases (CVDs) are the leading causes of morbidity and mortality worldwide. The escalating global occurrence of obesity and diabetes mellitus (DM) has led to a significant upsurge in individuals afflicted with CVDs. As the prevalence of CVDs continues to rise, it is becoming increasingly important to identify the underlying cellular and molecular mechanisms that contribute to their development and progression, which will help discover novel therapeutic avenues. Adipose tissue (AT) is a connective tissue that plays a crucial role in maintaining lipid and glucose homeostasis. However, when AT is exposed to diseased conditions, such as DM, this tissue will alter its phenotype to become dysfunctional. AT is now recognized as a critical contributor to CVDs, especially in patients with DM. AT is comprised of a heterogeneous cellular population, which includes adipose-derived stem cells (ADSCs). ADSCs resident in AT are believed to regulate physiological cardiac function and have potential cardioprotective roles. However, recent studies have also shown that ADSCs from various adipose tissue depots become pro-apoptotic, pro-inflammatory, less angiogenic, and lose their ability to differentiate into various cell lineages upon exposure to diabetic conditions. This review aims to summarize the current understanding of the physiological roles of ADSCs, the impact of DM on ADSC phenotypic changes, and how these alterations may contribute to the pathogenesis of CVDs.

Potential role of epicardial adipose tissue in coronary artery endothelial cell dysfunction in type 2 diabetes.

Cardiovascular disease is the most prevalent cause of morbidity and mortality in diabetes. Epicardial adipose tissue (EAT) lies in direct contact with the myocardium and coronary arteries and can influence cardiac (patho) physiology through paracrine signaling pathways. This study hypothesized that the proteins released from EAT represent a critical molecular link between the diabetic state and coronary artery endothelial cell dysfunction. To simulate type 2 diabetes-associated metabolic and inflammatory status in an ex vivo tissue culture model, human EAT samples were treated with a cocktail composed of high glucose, high palmitate, and lipopolysaccharide (gplEAT) and were compared with control EAT (conEAT). Compared to conEAT, gplEAT showed a markedly increased gene expression profile of proinflammatory cytokines, corroborating EAT inflammation, a hallmark feature observed in patients with type 2 diabetes. Luminex assay of EAT-secretome identified increased release of various proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha), interferon-alpha 2 (IFNA2), interleukin 1 beta (IL1B), interleukin 5 (IL5), interleukin 13 (IL13), and CCL5, among others, in response to high glucose, high palmitate, and lipopolysaccharide. Conditioned culture media was used to collect the concentrated proteins (CPs). In response to gplEAT-CPs, human coronary artery endothelial cells (HCAECs) exhibited an inflammatory endothelial cell phenotype, featuring a significantly increased gene expression of proinflammatory cytokines and cell surface expression of VCAM-1. Moreover, gplEAT-CPs severely decreased Akt-eNOS signaling, nitric oxide production, and angiogenic potential of HCAECs, when compared with conEAT-CPs. These findings indicate that EAT inflammation may play a key role in coronary artery endothelial cell dysfunction in type 2 diabetes.

Attenuation of Smooth Muscle Cell Phenotypic Switching by Angiotensin 1-7 Protects against Thoracic Aortic Aneurysm.

Thoracic aortic aneurysm (TAA) involves extracellular matrix (ECM) remodeling of the aortic wall, leading to reduced biomechanical support with risk of aortic dissection and rupture. Activation of the renin-angiotensin system, and resultant angiotensin (Ang) II synthesis, is critically involved in the onset and progression of TAA. The current study investigated the effects of angiotensin (Ang) 1-7 on a murine model of TAA. Male 8-10-week-old ApoEKO mice were infused with Ang II (1.44 mg/kg/day) and treated with Ang 1-7 (0.576 mg/kg/day). ApoEKO mice developed advanced TAA in response to four weeks of Ang II infusion. Echocardiographic and histological analyses demonstrated increased aortic dilatation, excessive structural remodelling, perivascular fibrosis, and inflammation in the thoracic aorta. Ang 1-7 infusion led to attenuation of pathological phenotypic alterations associated with Ang II-induced TAA. Smooth muscle cells (SMCs) isolated from adult murine thoracic aorta exhibited excessive mitochondrial fission, oxidative stress, and hyperproliferation in response to Ang II. Treatment with Ang 1-7 resulted in inhibition of mitochondrial fragmentation, ROS generation, and hyperproliferation. Gene expression profiling used for characterization of the contractile and synthetic phenotypes of thoracic aortic SMCs revealed preservation of the contractile phenotype with Ang 1-7 treatment. In conclusion, Ang 1-7 prevented Ang II-induced vascular remodeling and the development of TAA. Enhancing Ang 1-7 actions may provide a novel therapeutic strategy to prevent or delay the progression of TAA.

Inside(sight) of tiny communicator: exosome biogenesis, secretion, and uptake.

Discovered in the late 1980s as an extracellular vesicle of endosomal origin secreted from reticulocytes, exosomes recently gained scientific attention due to its role in intercellular communication. Exosomes have now been identified to carry cell-specific cargo of nucleic acids, proteins, lipids, and other biologically active molecules. Exosomes can be selectively taken up by neighboring or distant cells, which has shown to result in structural and functional responses in the recipient cells. Recent advances indicate the regulation of exosomes at various steps, including their biogenesis, selection of their cargo, as well as cell-specific uptake. This review will shed light on the differences between the type of extracellular vesicles. In this review, we discuss the recent progress in our understanding of the regulation of exosome biogenesis, secretion, and uptake.

Isolation and Characterization of Extracellular Vesicles from Cell Culture Media.

Extracellular vesicles (EVs) were once believed to serve as a means of disposing of cellular waste. However, recent discoveries have identified their crucial roles in intercellular communication between neighboring and distant cells. Almost all cell types have now been identified to produce EVs, which play a vital role in transporting cellular cargo. The functional roles of EVs, along with their implications in (patho)physiology of various diseases, are still being explored. In the last decade, the identification of EV roles in pathophysiology, pharmacology, and diagnostics has gained significant interest, albeit the development of universal methods for the isolation and characterization of EVs has been the limiting factor. A further challenge is ensuring that EVs of various size categories, which are thought to be produced via independent cellular mechanisms and often differ in their cargo and physiological purpose, can be separated and studied in isolation.This protocol provides an efficient and accessible method for isolating and characterizing EV samples from conditioned cell culture media. The combination of differential centrifugation and the use of a commercial EV-precipitation kit allows for the rapid isolation of a highly pure sample of EVs separated by size. A microfluidic resistive pulse sensing (MRPS)-based method is then used to quantify the particles, as well as to assess the size distribution of the EV sample. As a result, this protocol provides a reproducible means to isolate and characterize EVs of a variety of sizes from nearly any cultured cells.

Exploring the role of pericardial miRNAs and exosomes in modulating cardiac fibrosis.

The potential of the pericardial space as a therapeutic delivery tool for cardiac fibrosis and heart failure (HF) treatment has yet to be elucidated. Recently, miRNAs and exosomes have been discovered to be present in human pericardial fluid (PF). Novel studies have shown characteristic human PF miRNA compositions associated with cardiac diseases and higher miRNA expressions in PF compared to peripheral blood. Five key studies found differentially expressed miRNAs in HF, angina pectoris, aortic stenosis, ventricular tachycardia, and congenital heart diseases with either atrial fibrillation or sinus rhythm. As miRNA-based therapeutics for cardiac fibrosis and HF showed promising results in several in vivo studies for multiple miRNAs, we hypothesize a potential role of miRNA-based therapeutics delivered through the pericardial cavity. This is underlined by the favorable results of the first phase 1b clinical trial in this emerging field. Presenting the first human miRNA antisense drug trial, inhibition of miR-132 by intravenous administration of a novel antisense oligonucleotide, CDR132L, established efficacy in reducing miR-132 in plasma samples in a dose-dependent manner. We screened the literature, provided an overview of the miRNAs and exosomes present in PF, and drew a connection to those miRNAs previously elucidated in cardiac fibrosis and HF. Further, we speculate about clinical implications and potential delivery methods.

Inhibition of smooth muscle cell death by Angiotensin 1-7 protects against abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) represents a debilitating vascular disease characterized by aortic dilatation and wall rupture if it remains untreated. We aimed to determine the effects of Ang 1-7 in a murine model of AAA and to investigate the molecular mechanisms involved. Eight- to 10-week-old apolipoprotein E-deficient mice (ApoEKO) were infused with Ang II (1.44 mg/kg/day, s.c.) and treated with Ang 1-7 (0.576 mg/kg/day, i.p.). Echocardiographic and histological analyses showed abdominal aortic dilatation and extracellular matrix remodeling in Ang II-infused mice. Treatment with Ang 1-7 led to suppression of Ang II-induced aortic dilatation in the abdominal aorta. The immunofluorescence imaging exhibited reduced smooth muscle cell (SMC) density in the abdominal aorta. The abdominal aortic SMCs from ApoEKO mice exhibited markedly increased apoptosis in response to Ang II. Ang 1-7 attenuated cell death, as evident by increased SMC density in the aorta and reduced annexin V/propidium iodide-positive cells in flow cytometric analysis. Gene expression analysis for contractile and synthetic phenotypes of abdominal SMCs showed preservation of contractile phenotype by Ang 1-7 treatment. Molecular analyses identified increased mitochondrial fission, elevated cellular and mitochondrial reactive oxygen species (ROS) levels, and apoptosis-associated proteins, including cytochrome c, in Ang II-treated aortic SMCs. Ang 1-7 mitigated Ang II-induced mitochondrial fission, ROS generation, and levels of pro-apoptotic proteins, resulting in decreased cell death of aortic SMCs. These results highlight a critical vasculo-protective role of Ang 1-7 in a degenerative aortic disease; increased Ang 1-7 activity may provide a promising therapeutic strategy against the progression of AAA.

Adventitial Fibroblasts in Aortic Aneurysm: Unraveling Pathogenic Contributions to Vascular Disease.

Aortic aneurysm (AA) is a degenerative vascular disease that involves aortic dilatation, and, if untreated, it can lead to rupture. Despite its significant impact on the healthcare system, its multifactorial nature and elusive pathophysiology contribute to limited therapeutic interventions that prevent the progression of AA. Thus, further research into the mechanisms underlying AA is paramount. Adventitial fibroblasts are one of the key constituents of the aortic wall, and they play an essential role in maintaining vessel structure and function. However, adventitial fibroblasts remain understudied when compared with endothelial cells and smooth muscle cells. Adventitial fibroblasts facilitate the production of extracellular matrix (ECM), providing structural integrity. However, during biomechanical stress and/or injury, adventitial fibroblasts can be activated into myofibroblasts, which move to the site of injury and secrete collagen and cytokines, thereby enhancing the inflammatory response. The overactivation or persistence of myofibroblasts has been shown to initiate pathological vascular remodeling. Therefore, understanding the underlying mechanisms involved in the activation of fibroblasts and in regulating myofibroblast activation may provide a potential therapeutic target to prevent or delay the progression of AA. This review discusses mechanistic insights into myofibroblast activation and associated vascular remodeling, thus illustrating the contribution of fibroblasts to the pathogenesis of AA.

Proteomic Analysis Suggests Altered Mitochondrial Metabolic Profile Associated With Diabetic Cardiomyopathy.

Diabetic cardiomyopathy (DbCM) occurs independently of cardiovascular diseases or hypertension, leading to heart failure and increased risk for death in diabetic patients. To investigate the molecular mechanisms involved in DbCM, we performed a quantitative proteomic profiling analysis in the left ventricle (LV) of type 2 diabetic mice. Six-month-old C57BL/6J-lepr/lepr (db/db) mice exhibited DbCM associated with diastolic dysfunction and cardiac hypertrophy. Using quantitative shotgun proteomic analysis, we identified 53 differentially expressed proteins in the LVs of db/db mice, majorly associated with the regulation of energy metabolism. The subunits of ATP synthase that form the F1 domain, and Cytochrome c1, a catalytic core subunit of the complex III primarily responsible for electron transfer to Cytochrome c, were upregulated in diabetic LVs. Upregulation of these key proteins may represent an adaptive mechanism by diabetic heart, resulting in increased electron transfer and thereby enhancement of mitochondrial ATP production. Conversely, diabetic LVs also showed a decrease in peptide levels of NADH dehydrogenase 1ß subcomplex subunit 11, a subunit of complex I that catalyzes the transfer of electrons to ubiquinone. Moreover, the atypical kinase COQ8A, an essential lipid-soluble electron transporter involved in the biosynthesis of ubiquinone, was also downregulated in diabetic LVs. Our study indicates that despite attempts by hearts from diabetic mice to augment mitochondrial ATP energetics, decreased levels of key components of the electron transport chain may contribute to impaired mitochondrial ATP production. Preserved basal mitochondrial respiration along with the markedly reduced maximal respiratory capacity in the LVs of db/db mice corroborate the association between altered mitochondrial metabolic profile and cardiac dysfunction in DbCM.

Exosomes in Cardiovascular Diseases: Pathological Potential of Nano-Messenger.

Cardiovascular diseases (CVDs) represent a major global health problem, due to their continued high incidences and mortality. The last few decades have witnessed new advances in clinical research which led to increased survival and recovery in CVD patients. Nevertheless, elusive and multifactorial pathophysiological mechanisms of CVD development perplexed researchers in identifying efficacious therapeutic interventions. Search for novel and effective strategies for diagnosis, prevention, and intervention for CVD has shifted research focus on extracellular vesicles (EVs) in recent years. By transporting molecular cargo from donor to recipient cells, EVs modulate gene expression and influence the phenotype of recipient cells, thus EVs prove to be an imperative component of intercellular signaling. Elucidation of the role of EVs in intercellular communications under physiological conditions implied the enormous potential of EVs in monitoring and treatment of CVD. The EVs secreted from the myriad of cells in the cardiovascular system such as cardiomyocytes, cardiac fibroblasts, cardiac progenitor cells, endothelial cells, inflammatory cells may facilitate the communication in physiological and pathological conditions. Understanding EVs-mediated cellular communication may delineate the mechanism of origin and progression of cardiovascular diseases. The current review summarizes exosome-mediated paracrine signaling leading to cardiovascular disease. The mechanistic role of exosomes in cardiovascular disease will provide novel avenues in designing diagnosis and therapeutic interventions.