Microparticles Carrying Sonic Hedgehog Are Increased in Humans with Peripheral Artery Disease

Extracellular vesicles in atherosclerosis: Current and forthcoming impact?

Atherosclerosis is the main pathogenic substrate for cardiovascular diseases (CVDs). Initially categorized as a passive cholesterol storage disease, nowadays, it is considered an active process, identifying inflammation among the key players for its initiation and progression. Despite these advances, patients with CVDs are still at high risk of thrombotic events and death, urging to deepen into the molecular mechanisms underlying atherogenesis, and to identify novel diagnosis and prognosis biomarkers for their stratification. In this context, extracellular vesicles (EVs) have been postulated as an alternative in search of novel biomarkers in atherosclerotic diseases, as well as to investigate the crosstalk between the cells participating in the processes leading to arterial remodelling. EVs are nanosized lipidic particles released by most cell types in physiological and pathological conditions, that enclose lipids, proteins, and nucleic acids from parental cells reflecting their activation status. First considered cellular waste disposal systems, at present, EVs have been recognized as active effectors in a myriad of cellular processes, and as potential diagnosis and prognosis biomarkers also in CVDs. This review summarizes the role of EVs as potential biomarkers of CVDs, and their involvement into the processes leading to atherosclerosis.

Serum levels of sonic hedgehog in patients with IgA nephropathy are closely associated with intrarenal arteriolar lesions

BACKGROUND

Intrarenal arteriolar disease is a major risk factor for poor prognosis in immunoglobulin A nephropathy (IgAN). The morphologic factor sonic hedgehog (SHH) plays an important role in a variety of vascular diseases, so it may be directly or indirectly involved in the process of renal arteriolar disease. The purpose of this study was to investigate the correlation between serum SHH levels and renal arteriole disease in patients with IgAN.

METHODS

Subjects with primary IgAN diagnosed by renal biopsy performed between October 2018 and August 2019 at the First Medical Center of the Chinese PLA General Hospital were recruited. Blood specimens were collected from the patients within 1 week before renal biopsy after they signed an informed consent form, and healthy controls were recruited for blood specimen collection during the same period. The concentration of serum SHH was measured by enzyme-linked immunosorbent assay in this population.

RESULTS

Serum SHH levels were significantly lower in the IgAN group than in the control group. 41 of the 94 subjects diagnosed with IgAN had severe renal arteriolosclerosis and, compared to their less severely affected counterparts, were older, more hypertensive, and characterized by lower levels of SHH, higher levels of tubular atrophy/interstitial fibrosis and a higher Lee's classification. Serum SHH concentration was found to be an independent predictor of severe intrarenal arteriolosclerosis in IgAN subjects after correction using multivariate analysis.

CONCLUSION

In this study, serum SHH levels were found to be significantly lower in patients with IgAN than in healthy subjects. Serum SHH may serve as a noninvasive biomarker of intrarenal arteriolosclerosis in patients with IgAN.

Transcriptomic and Proteomic of Gastrocnemius Muscle in Peripheral Artery Disease

BACKGROUND

Few effective therapies exist to improve lower extremity muscle pathology and mobility loss due to peripheral artery disease (PAD), in part because mechanisms associated with functional impairment remain unclear.

METHODS

To better understand mechanisms of muscle impairment in PAD, we performed in-depth transcriptomic and proteomic analyses on gastrocnemius muscle biopsies from 31 PAD participants (mean age, 69.9 years) and 29 age- and sex-matched non-PAD controls (mean age, 70.0 years) free of diabetes or limb-threatening ischemia.

RESULTS

Transcriptomic and proteomic analyses suggested activation of hypoxia-compensatory mechanisms in PAD muscle, including inflammation, fibrosis, apoptosis, angiogenesis, unfolded protein response, and nerve and muscle repair. Stoichiometric proportions of mitochondrial respiratory proteins were aberrant in PAD compared to non-PAD, suggesting that respiratory proteins not in complete functional units are not removed by mitophagy, likely contributing to abnormal mitochondrial activity. Supporting this hypothesis, greater mitochondrial respiratory protein abundance was significantly associated with greater complex II and complex IV respiratory activity in non-PAD but not in PAD. Rate-limiting glycolytic enzymes, such as hexokinase and pyruvate kinase, were less abundant in muscle of people with PAD compared with non-PAD participants, suggesting diminished glucose metabolism.

CONCLUSIONS

In PAD muscle, hypoxia induces accumulation of mitochondria respiratory proteins, reduced activity of rate-limiting glycolytic enzymes, and an enhanced integrated stress response that modulates protein translation. These mechanisms may serve as targets for disease modification.

Extracellular vesicles and atherosclerotic peripheral arterial disease

Atherogenesis involves a complex multifactorial process including chronic inflammation that requires the participation of several cell types and molecules. In addition to their role in vascular homeostasis, extracellular vesicles also appear to play an important role in atherogenesis, including monocyte transmigration and foam cell formation, SMC proliferation and migration, leukocyte transmigration, and thrombosis. Peripheral arterial disease, a major form of peripheral vascular disease, is characterized by structural or functional impairment of peripheral arterial supply, often secondary to atherosclerosis. Elevated levels of extracellular vesicles have been demonstrated in patients with peripheral arterial disease and implicated in the development of atherosclerosis within peripheral vascular beds. However, extracellular vesicles also appear capable of delivering cargo with atheroprotective effects. This capability has been exploited in vesicles engineered to carry content capable of neovascularization, suggesting potential for therapeutic angiogenesis. This dual capacity holds substantial promise for diagnosis and therapy, including possibly limb- and life-saving options for peripheral arterial disease management.

Sonic hedgehog N-terminal level correlates with adiponectin level and insulin resistance in adolescents

OBJECTIVES

Extracellular vesicles (EVs) are small vesicles released by nearly all types of cells. They deliver different types of substances, including proteins and nucleic acids, to nearby or distant cells and play a role in the mediation of cell-to-cell communication. The aim of this study was to explore the association between EVs and insulin resistance in adolescents with obesity or type 2 diabetes mellitus (DM2).

METHODS

The subjects were eight adolescents with DM2 (DM2 group; four males and four females; age: 18.1 ± 2.3 years), 18 adolescents with simple obesity (obesity group; 12 males and six females; age: 12.2 ± 3.4 years), and 20 controls (control group; 10 males and 10 females; age: 13.0 ± 1.4 years). As markers of EVs, serum CD9/CD63 and sonic hedgehog N-terminal (Shh-N) levels were measured using enzyme-linked immunosorbent assay.

RESULTS

The CD9/CD63 level in the control group was similar to that in the DM2 group, whereas the obesity group had a significantly higher CD9/CD63 level. In the entire study group, correlations were observed between serum Shh-N level and Homeostasis Model Assessment of insulin resistance (HOMA-IR) score (r=0.371, p=0.0143), Homeostasis Model Assessment-β cell function score (r=0.382, p=0.0115), serum insulin level (r=0.350, p=0.0171), and serum adiponectin level (r=0.367, p=0.0122). Multiple regression analysis revealed that serum Shh-N level was the most significant risk factor for HOMA-IR score and serum insulin level.

CONCLUSIONS

Shh is correlated with insulin resistance via its association with adiponectin in adolescents.

Extracellular Vesicles as Drivers of Immunoinflammation in Atherothrombosis

Atherosclerotic cardiovascular disease is the leading cause of morbidity and mortality all over the world. Extracellular vesicles (EVs), small lipid-bilayer membrane vesicles released by most cellular types, exert pivotal and multifaceted roles in physiology and disease. Emerging evidence emphasizes the importance of EVs in intercellular communication processes with key effects on cell survival, endothelial homeostasis, inflammation, neoangiogenesis, and thrombosis. This review focuses on EVs as effective signaling molecules able to both derail vascular homeostasis and induce vascular dysfunction, inflammation, plaque progression, and thrombus formation as well as drive anti-inflammation, vascular repair, and atheroprotection. We provide a comprehensive and updated summary of the role of EVs in the development or regression of atherosclerotic lesions, highlighting the link between thrombosis and inflammation. Importantly, we also critically describe their potential clinical use as disease biomarkers or therapeutic agents in atherothrombosis.

The Overexpression of Sonic Hedgehog Associates with Collateral Development and Amelioration of Oxidative Stress in Stroke Patients

PURPOSE

Sonic hedgehog (SHH) signaling pathway in oxidative stress condition has been acknowledged as a key trigger for angiogenesis and collateral vessel growth in the ischemic brain, and it exerts a protective effect on neuronal cells during oxidative stress.

METHODS

A total of sixty patients (n = 30 good collateral profile and n = 30 poor collateral profile) diagnosed with acute cerebral ischemia were enrolled in this study. qRT-PCR was performed to analyze the expression levels of SHH, Gli1, and superoxide dismutase (SOD), genes. Also, the serum levels of oxidative stress markers were determined in experimental groups.

RESULTS

The expression levels of SHH and Gli1 genes were significantly (p < 0.05) higher in stroke patients with good collateral circulation compared with those with poor collateral circulation, while SOD gene expression was similar between two groups (p > 0.05). A significantly positive correlation was found between the gene expression of SHH and Gli1 (r = 0.604, p < 0.001), SOD and Gli1 (r = 0.372, p < 0.003) genes. Our findings showed that the serum level of total antioxidant capacity (TAC) and Glutathione (GSH) and SOD enzyme activity was significantly (p < 0.05) increased, while serum total oxidant status (TOS) and malondialdehyde (MDA) levels were significantly (p < 0.05) decreased in patients with good collateral circulation as compared with those with poor collateral circulation.

CONCLUSION

Our observations shed light on the association of the SHH/Gli1 signaling pathway with cerebral collateral vessel development following ischemia. Oxidative stress in stroke patients with poor collateral circulation may result in the overexpression of SHH/Gli1 signaling pathway which possibly contribute to oxidative stress attenuation, as well as modulate angiogenesis and collateral vessels development.

Role of Extracellular Vesicles as Potential Diagnostic and/or Therapeutic Biomarkers in Chronic Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the first cause of death worldwide. In recent years, there has been great interest in the analysis of extracellular vesicles (EVs), including exosomes and microparticles, as potential mediators of biological communication between circulating cells/plasma and cells of the vasculature. Besides their activity as biological effectors, EVs have been also investigated as circulating/systemic biomarkers in different acute and chronic CVDs. In this review, the role of EVs as potential diagnostic and prognostic biomarkers in chronic cardiovascular diseases, including atherosclerosis (mainly, peripheral arterial disease, PAD), aortic stenosis (AS) and aortic aneurysms (AAs), will be described. Mechanistically, we will analyze the implication of EVs in pathological processes associated to cardiovascular remodeling, with special emphasis in their role in vascular and valvular calcification. Specifically, we will focus on the participation of EVs in calcium accumulation in the pathological vascular wall and aortic valves, involving the phenotypic change of vascular smooth muscle cells (SMCs) or valvular interstitial cells (IC) to osteoblast-like cells. The knowledge of the implication of EVs in the pathogenic mechanisms of cardiovascular remodeling is still to be completely deciphered but there are promising results supporting their potential translational application to the diagnosis and therapy of different CVDs.

The Role of Circulating Biomarkers in Peripheral Arterial Disease

Peripheral arterial disease (PAD) of the lower extremities is a chronic illness predominantly of atherosclerotic aetiology, associated to traditional cardiovascular (CV) risk factors. It is one of the most prevalent CV conditions worldwide in subjects >65 years, estimated to increase greatly with the aging of the population, becoming a severe socioeconomic problem in the future. The narrowing and thrombotic occlusion of the lower limb arteries impairs the walking function as the disease progresses, increasing the risk of CV events (myocardial infarction and stroke), amputation and death. Despite its poor prognosis, PAD patients are scarcely identified until the disease is advanced, highlighting the need for reliable biomarkers for PAD patient stratification, that might also contribute to define more personalized medical treatments. In this review, we will discuss the usefulness of inflammatory molecules, matrix metalloproteinases (MMPs), and cardiac damage markers, as well as novel components of the liquid biopsy, extracellular vesicles (EVs), and non-coding RNAs for lower limb PAD identification, stratification, and outcome assessment. We will also explore the potential of machine learning methods to build prediction models to refine PAD assessment. In this line, the usefulness of multimarker approaches to evaluate this complex multifactorial disease will be also discussed.

Liquid Biopsies: Microvesicles in Cardiovascular Disease

Significance: Circulating microvesicles (cMV) are small (0.1-1 μm) phospholipid-rich blebs released by almost all cell types, and their release increases with cell activation and injury, thus reflecting the state of the cell from which they are originated. Microvesicles (MV) are found in the bloodstream, and they affect the phenotype of recipient cells, after local or systemic circulation, by intercellular transfer of their molecular content. Recent Advances: Several studies suggest the use of cell-specific MV subpopulations as predictive biomarkers for cardiovascular diseases (CVDs) at different stages and degrees of severity. In this review, we describe the state of the art of cMV as noninvasive surrogate biomarkers of vascular injury and dysfunction correlated with poor clinical outcomes in CVD. Critical Issues: Despite the growing body of evidence supporting the importance of cMV as hallmarks of CVD and their utility as biomarkers of CVD, the specific roles of each phenotype of cMV in CVD burden and prognosis still remain to be elucidated and validated in large cohorts. In addition, the development of standardized and reproducible techniques is required to be used as biomarkers for disease progression in the clinical setting. Future Directions: A multipanel approach with specific cMV phenotypes, added to current biomarkers and scores, will undoubtedly provide unique prognostic information to stratify patients for appropriate therapy on the basis of their risk of atherothrombotic disease and will open a new research area as therapeutic targets for CVD. MV will add to the implementation of precision medicine by helping the cellular and molecular characterization of CVD patients.

Circulating microparticle concentrations across acute and chronic cardiovascular disease conditions

Concentrations of different circulating microparticles (MPs) may have clinical and physiological relevance to cardiovascular disease pathologies.

PURPOSE

To quantify plasma concentrations of CD31+/CD42b-, CD62E+, and CD34+ MPs across healthy individuals and those with coronary artery disease (CAD) or acute cardiovascular events (non-ST elevation myocardial infarction (NSTEMI)). Fasted blood was obtained from CAD patients (n = 10), NSTEMI patients (n = 13), and healthy older men (n = 15) 60-75 years old.

METHODS

CD31+/CD42b-, CD62E+, and CD34+ MPs were isolated from plasma and quantified using flow cytometry. Relationships between MP subtypes, fasting blood lipids, blood glucose, blood pressure, body mass index, and total number of medications were assessed.

RESULTS

Concentrations of CD31+/CD42b- MPs were significantly lower in CAD and NSTEMI subjects compared with healthy individuals (p = .02 and .003, respectively). No differences between groups were found for CD62E+ or CD34+ MPs (p > .05 for both). Surprisingly, among all variables assessed, only CD62E+ MP concentrations were positively correlated with triglyceride levels (p = .012) and inversely correlated with SBP (p = .03).

CONCLUSIONS

Our findings provide support for the use of different MP subtypes, specifically CD31+/CD42b- MPs, as a potential biomarker of cardiovascular disease. Importantly, results from this study should be looked at in adjunct to previous MP work in CVD conditions as a way of highlighting the complex interactions of variables such as comorbid conditions and medications on MP concentrations.

Functional and transcriptomic analysis of extracellular vesicles identifies calprotectin as a new prognostic marker in peripheral arterial disease (PAD)

Peripheral arterial disease (PAD) is associated with a high risk of cardiovascular events and death and is postulated to be a critical socioeconomic cost in the future. Extracellular vesicles (EVs) have emerged as potential candidates for new biomarker discovery related to their protein and nucleic acid cargo. In search of new prognostic and therapeutic targets in PAD, we determined the prothrombotic activity, the cellular origin and the transcriptomic profile of circulating EVs. This prospective study included control and PAD patients. Coagulation time (Procoag-PPL kit), EVs cellular origin and phosphatidylserine exposure were determined by flow cytometry in platelet-free plasma (n = 45 PAD). Transcriptomic profiles of medium/large EVs were generated using the MARS-Seq RNA-Seq protocol (n = 12/group). The serum concentration of the differentially expressed gene S100A9, in serum calprotectin (S100A8/A9), was validated by ELISA in control (n = 100) and PAD patients (n = 317). S100A9 was also determined in EVs and tissues of human atherosclerotic plaques (n = 3). Circulating EVs of PAD patients were mainly of platelet origin, predominantly Annexin V positive and were associated with the procoagulant activity of platelet-free plasma. Transcriptomic analysis of EVs identified 15 differentially expressed genes. Among them, serum calprotectin was elevated in PAD patients (p < 0.05) and associated with increased amputation risk before and after covariate adjustment (mean follow-up 3.6 years, p < 0.01). The combination of calprotectin with hs-CRP in the multivariate analysis further improved risk stratification (p < 0.01). Furthermore, S100A9 was also expressed in femoral plaque derived EVs and tissues. In summary, we found that PAD patients release EVs, mainly of platelet origin, highly positive for AnnexinV and rich in transcripts related to platelet biology and immune responses. Amputation risk prediction improved with calprotectin and was significantly higher when combined with hs-CRP. Our results suggest that EVs can be a promising component of liquid biopsy to identify the molecular signature of PAD patients.

The Hedgehog Signaling Pathway in Ischemic Tissues

Hedgehog (Hh) proteins are prototypical morphogens known to regulate epithelial/mesenchymal interactions during embryonic development. In addition to its pivotal role in embryogenesis, the Hh signaling pathway may be recapitulated in post-natal life in a number of physiological and pathological conditions, including ischemia. This review highlights the involvement of Hh signaling in ischemic tissue regeneration and angiogenesis, with particular attention to the heart, the brain, and the skeletal muscle. Updated information on the potential role of the Hh pathway as a therapeutic target in the ischemic condition is also presented.