Crosstalk of human coronary perivascular adipose-derived stem cells with vascular cells: role of tissue factor

The coronary perivascular adipose tissue (cPVAT) has been associated to the burden of cardiovascular risk factors and to the underlying vessel atherosclerotic plaque severity. Although the "outside to inside" hypothesis of PVAT-derived-adipokine regulation of vessel function is currently accepted, whether the resident mesenchymal stem cells (ASCs) in PVAT have a regulatory role on the underlying vascular arterial smooth muscle cells (VSMCs) is not known. Here, we investigated the interactions between resident PVAT-ASCs and VSMCs. ASCs were obtained from PVAT overlying the left anterior descending (LAD) coronary artery of hearts removed at heart transplant operations. PVAT was obtained both from patients with non-ischemic and ischemic heart disease as the cause of heart transplant. ASCs were isolated from PVAT, phenotypically characterized by flow cytometry, functionally tested for proliferation, and differentiation. Crosstalk between ASCs and VSMCs was investigated by co-culture studies. ASCs were detected in the adventitia of the LAD-PVAT showing differentiation capacity and angiogenic potential. ASCs obtained from PVAT of non-ischemic and ischemic hearts showed different tissue factor (TF) expression levels, different VSMCs recruitment capacity through the axis ERK1/2-ETS1 signaling and different angiogenic potential. Induced upregulation of TF in ASCs isolated from ischemic PVAT rescued their angiogenic capacity in subcutaneously implanted plugs in mice, whereas silencing TF in ASCs decreased the proangiogenic capacity of non-ischemic ASCs. The results indicate for the first time a novel mechanism of regulation of VSMCs by PVAT-ASCs in angiogenesis, mediated by TF expression in ASCs. Regulation of TF in ASCs may become a therapeutic intervention to increase cardiac protection.

Safety and effectiveness of direct-acting antiviral drugs in the treatment of hepatitis C in patients with inflammatory bowel disease

BACKGROUND AND AIMS

Hepatitis C virus (HCV) management in Inflammatory Bowel Disease (IBD) is uncertain. The ECCO guidelines 2021 recommended HCV treatment but warn about the risk of IBD reactivation. We aimed to evaluate 1) the effectiveness and safety of direct-acting antivirals (DAAs) in IBD; 2) the interaction of DAAs with IBD drugs.

METHODS

Multicentre study of IBD patients and HCV treated with DAAs. Variables related to liver diseases and IBD, as well as adverse events (AEs) and drug interactions, were recorded. McNemar's test was used to assess differences in the proportion of active IBD during the study period.

RESULTS

We included 79 patients with IBD and HCV treated with DAAs from 25,998 IBD patients of the ENEIDA registry. Thirty-one (39.2 %) received immunomodulators/biologics. There were no significant differences in the percentage of active IBD at the beginning (n = 11, 13.9 %) or at the 12-week follow-up after DAAs (n = 15, 19 %) (p = 0.424). Sustained viral response occurred in 96.2 % (n = 76). A total of 8 (10.1 %) AEs occurred and these were unrelated to activity, type of IBD, liver fibrosis, immunosuppressants/biologics, and DAAs.

CONCLUSIONS

We demonstrate a high efficacy and safety of DAAs in patients with IBD and HCV irrespective of activity and treatment of IBD.

Short-term recovery of soil and pine tree canopy after late prescribed burning in a semi-arid landscape

Climate change worsening due to global warming and progressive abandonment in rural areas mean that wildfires are increasing in extent and severity terms, and are one of the major disturbances in the Mediterranean Basin. To mitigate these disturbances, preventive management tools need to be used. Fire employment is being implemented, known as prescribed burnings, as forestry actions to change vegetation lines both vertically and horizontally to eliminate forest fuel load continuity. This study aimed to know the ecological effects of late prescribed burning treatments under mixed trees. Prescribed burns were carried out in October 2019 in the municipality of Ayna, Albacete (SE Spain). To assess the short-term (12-month) fire impact on soil, we measured soil respiration with a CO₂ flow chamber and analyzed soil physico-chemical properties. We also used minidisc infiltrometers to analyze soil repellency and soil hydraulic conductivity over a 1-year monitoring period. In addition, we evaluated the effects on tree strata by performing chemical nature analyses of fallen needles in Pinus pinaster after prescribed burning. According to our initial hypotheses, the results did not show significant changes in any parameter evaluated during the study period. However, some variables were affected in the first 3 months, needlefall and in microbiological activity, such as variations in soil physico-chemical properties, which can be due to long dry seasons combined with prescribed burning. This study attempts to observe and make known the effects that low-intensity prescribed burning has on soil and needlefall, which are relevant for updating forest management tools.

Endothelium-Released Microvesicles Transport miR-126 That Induces Proangiogenic Reprogramming in Monocytes

We have recently shown that in ischemic tissue, the hypoxic endothelial cells (EC) release extracellular microvesicles (EMVs) that are rich in tissue factor (TF). These TF-EMVs induce monocyte (Mo) homing to the ischemic zone, their differentiation into EC-like cells, and the formation of new blood vessels increasing tissue perfusion. In addition to membrane proteins, EMVs contain noncoding RNAs that can modulate cellular signaling pathways in the recipient cells. Here, we have investigated whether miRNA contained into secreted EMVs may be transferred into Mo where they could modulate EC-like cell differentiation and angiogenic responses. Our results indicated that EMVs released from activated ECs contain high levels of miR-126 and that the levels are directly proportional to TF expression in EMVs. Interestingly, miR-126 is transferred to Mo when they are incubated with TF-EMVs. Increased levels of miR-126 in Mo do not promote EC-like cell differentiation but regulate angiogenesis by targeting several components of the VEGF pathway, as SPRED1 and PI3KR2. Our findings reveal that activated ECs secrete EMVs carrying miR-126, which can modulate Mo reprogramming of angiogenic genes.

Molecular mapping of platelet hyperreactivity in diabetes: the stress proteins complex HSPA8/Hsp90/CSK2α and platelet aggregation in diabetic and normal platelets

The molecular understanding of the pathophysiological changes elicited by diabetes in platelets may help in further elucidating the involvement of this pseudo-cell in the increased risk of developing cardiovascular disease and thrombosis in diabetic subjects. We aimed to investigate the differential characteristics of platelets from diabetic patients and nondiabetic controls to unveil the molecular mechanisms behind the increased platelet reactivity in diabetes. We compared platelets from diabetic and control subjects by 2 dimensional-electrophoresis followed by mass spectrometry. Changes in selected differential proteins were validated by immunoprecipitation assays and western blot. Platelet aggregation was measured by light transmittance aggregometry induced by collagen and ADP, and dynamic coagulation analysis of whole blood was measured by thromboelastometry. We observed significant differences in proteins related to platelet aggregation, cell migration, and cell homeostasis. Subjects with diabetes showed higher platelet aggregation and thrombogenicity and higher contents of the stress-related protein complex HSPA8/Hsp90/CSK2α than nondiabetic subjects. Changes in the chaperones HSPA8 and Hsp90, and in CSK2α protein contents correlated with changes in platelet aggregation and blood coagulation activity. In conclusion, the complex HSPA8/Hsp90/CSK2α is involved in diabetes-related platelet hyperreactivity. The role of the HSPA8/Hsp90/CSK2α complex may become a molecular target for the development of future preventive and therapeutic strategies for platelet dysfunction associated with diabetes and its complications.

Ischemic tissue released microvesicles induce monocyte reprogramming and increase tissue repair by a tissue factor-dependent mechanism

AIMS

Despite increasing evidence that monocytes may acquire endothelial features, it remains unclear how monocytes participate in angiogenesis after ischemic damage. We investigated whether ischemic cells can release microvesicles (MVs) and promote neovascularisation in a model of peripheral artery disease (PAD).

METHODS AND RESULTS

To model PAD we used an in vivo experimental model of hind limb ischemia (HLI) in mice. MVs were isolated from the ischemic muscle and from peripheral blood at different times after unilateral femoral artery ligation. MVs were phenotypically characterized to identify cell origin. HLI in mice induced the release of MVs with a much higher content of tissue factor (TF) than non-HLI control mice both in the MVs isolated from the affected limb muscle area and from blood. MVs were mainly released from endothelial cells (ECs) and induced Mo differentiation to endothelial cell-like (ECL) cells. Differentiation to ECL cells encompassed highly strict hierarchycal transcription factor activation, initiated by ETS1 activation. MVs secreted by microvascular ECs overexpressing TF (upTF-EMVs), were injected in the ischemic hind limb in parallel with control EMVs (from random siRNA-treated cells) or EMVs released by silenced TF endothelial cells (siTF-EMVs). In animals treated with upTF-EMVs in the ischemic zone there was a highly significant increase in functional new vessels formation (seen by magnetic resonance angiography), a concomitant increase in the pool of circulating Ly6Clow Mo expressing vascular endothelial cell markers, and a significantly higher number of Mo/Macrophages surrounding and integrating the newly formed collaterals.

CONCLUSION

Ischemia-activated ECs release EMVs rich in TF that induce monocyte differentiation into ECL cells and the formation of new vessels in the ischemic zone. TF by this mechanism of formation of new blood microvessels can contribute to ischemic tissue repair.

TRANSLATIONAL PERSPECTIVE

Neovascularization is the cornerstone of limb preservation in peripheral artery disease. Neovessel formation occurring during postnatal development is usually connected with inflammation. Advanced studies in the field of vascular biology have reported that monocytes can acquire endothelial features under angiogenic stimulation. We report that after ischemia affected endothelial cells release microvesicles rich in tissue factor that act as endogenous triggers by interacting with monocytes in an autocrine fashion, coaxing the cells to differentiate into functional endothelial cells. These differentiated cells have the ability to increase blood flow into ischemic tissue. The present study depicts a new concept in the mechanisms governing vessel formation in ischemic tissue.

POS0501 SUSTAINED 2-YEAR REMISSION OF THE DISEASE IN A CLINIC OF EXCELLENCE IN RHEUMATOID ARTHRITIS. EXPERIENCE OF THE CLINICAL REGISTRY IN COLOMBIA

Background:

Rheumatoid arthritis (RA) is a chronic autoimmune disease with no cure, characterized by episodes of exacerbation and remission, which requires permanent use of medications. Clinics of excellence are multidisciplinary and centralized programs that improve adherence to treatments. Information on the benefits of these models of care has been published but is not definitive. In Colombia, the clinical registry of patients with RA is kept in the Cuenta de Alto Costo (CAC).

Objectives:

To demonstrate the difference in the percentages of sustained remission at 2 years, between an institution with non-centralized management or standard of care (Hospital Militar Central-HMC) compared to another institution with centralized management or clinic of excellence (BIOMAB-IPS) and determine if the results are determined by any of the intervention variables or by the program.

Methods:

The 2-year clinical records for the CAC were compared between an institution with non-centralized management (HMC) in comparison with another institution with centralized management (BIOMAB-IPS), performing a sociodemographic description, measuring control of the disease DAS28 clinimetry, Fisher’s test non-parametric bivariate analysis, multiple regression model, and population matching with Propensity score Matching (PSM).

Results:

Complete information was obtained from 2 years of follow-up, in centralized management 3457 patients and for the non-centralized unit 114 patients. Most of them corresponded to 2962 women (82%), with time of illness of 9.5 years and 10.2 years, respectively, without statistically significant differences. A difference was observed in the 2 programs to maintain remission at 2 years, in favor of the centralized program 54.7% vs 28.6.2% (p <0.00). With the binomial generalized linear regression model, it was confirmed that this difference was not explained by variables such as the use of biological therapy (RR = 0.77; 95% CI 0.69-0.86), use of DMARDs (RR = 0.71; 95% CI 0.62-0.82) and number of rheumatology consultations (RR = 0.97; 95% CI 0.92-1.02) in comparison with the centralized care model (RR = 2.32; 95% CI 1.58-3.35). Due to the biases between the groups due to the non-probability sampling, a PSM was performed, with a 1: 1 match, caliper of 0.065, obtaining a pseudo population with well-balanced covariates (see table 1). In the common support area, statistically significant differences were documented in sustained remission over 2 years, in favor of the centralized care group 45 vs 17.9% (p = 0.001).

Conclusion:

With the information from the clinical records, statistical strategies can be used to evaluate important differences in centralized care programs, observing favorable results of these types of care that are not related to isolated elements of the program, but to the overall effect of the program.

References:

[1]Austin PC. Double propensity-score adjustment: A solution to design bias or bias due to incomplete matching. Stat Methods Med Res. 2017;26(1):201–22.33333

Disclosure of Interests:

Juan Manuel Bello-Gualtero: None declared, Esperanza Peña: None declared, Pedro Iván Santos Moreno: None declared, Jasmin Vesga Gualdrón Employee of: Baxter, Ginna Saavedra: None declared, Clara Perez: None declared

Alternative C3 Complement System: Lipids and Atherosclerosis

Familial hypercholesterolemia (FH) is increasingly associated with inflammation, a phenotype that persists despite treatment with lipid lowering therapies. The alternative C3 complement system (C3), as a key inflammatory mediator, seems to be involved in the atherosclerotic process; however, the relationship between C3 and lipids during plaque progression remains unknown. The aim of the study was to investigate by a systems biology approach the role of C3 in relation to lipoprotein levels during atherosclerosis (AT) progression and to gain a better understanding on the effects of C3 products on the phenotype and function of human lipid-loaded vascular smooth muscle cells (VSMCs). By mass spectrometry and differential proteomics, we found the extracellular matrix (ECM) of human aortas to be enriched in active components of the C3 complement system, with a significantly different proteomic signature in AT segments. Thus, C3 products were more abundant in AT-ECM than in macroscopically normal segments. Furthermore, circulating C3 levels were significantly elevated in FH patients with subclinical coronary AT, evidenced by computed tomographic angiography. However, no correlation was identified between circulating C3 levels and the increase in plaque burden, indicating a local regulation of the C3 in AT arteries. In cell culture studies of human VSMCs, we evidenced the expression of C3, C3aR (anaphylatoxin receptor) and the integrin α_Mβ₂ receptor for C3b/iC3b (RT-PCR and Western blot). C3mRNA was up-regulated in lipid-loaded human VSMCs, and C3 protein significantly increased in cell culture supernatants, indicating that the C3 products in the AT-ECM have a local vessel-wall niche. Interestingly, C3a and iC3b (C3 active fragments) have functional effects on VSMCs, significantly reversing the inhibition of VSMC migration induced by aggregated LDL and stimulating cell spreading, organization of F-actin stress fibers and attachment during the adhesion of lipid-loaded human VSMCs. This study, by using a systems biology approach, identified molecular processes involving the C3 complement system in vascular remodeling and in the progression of advanced human atherosclerotic lesions.

Triglyceride-induced cardiac lipotoxicity is mitigated by Silybum marianum

BACKGROUND AND AIMS

Silybum marianum (SM) is an herbal product with cytoprotective and antioxidant properties. We have previously demonstrated that SM ameliorates ventricular remodeling and improves cardiac performance. Here, we evaluated whether SM could exert beneficial effects against cardiac lipotoxicity in a pig model of closed-chest myocardial infarction (MI).

METHODS

Study 1 investigated the effect of SM administration on lipid profile and any potential SM-related adverse effects. Animals received SM or placebo during 10 days and were afterward sacrificed. Study 2 evaluated the effectiveness of SM daily administration in reducing cardiac lipotoxicity in animals subjected to a 1.5h myocardial infarction (MI), who were subsequently reperfused for 2.5h and euthanized or kept under study for three weeks and then sacrificed.

RESULTS

Animals administered a 10-day SM regime presented a sharp decline in plasma triglyceride levels vs. controls, with no other modifications in lipid profile. The decrease in triglyceride concentration was accompanied by a marked reduction in triglyceride intestinal absorption and glycoprotein-P expression. Three weeks post-MI the triglyceride content in the ischemic myocardium of the SM-treated animals was significantly lower than in the ischemic myocardium of placebo-controls. This effect was associated with an enhanced cardiac expression of PPARγ and triglyceride clearance receptors. This long-term SM-administration induced a lower expression of lipid receptors in subcutaneous adipose tissue. No SM-related side-effects were registered.

CONCLUSION

SM administration reduces plasma triglyceride levels through attenuation of triglyceride intestinal absorption and modulates cardiac lipotoxicity in the ischemic myocardium, likely contributing to improve ventricular remodeling.

High-density lipoprotein remodelled in hypercholesterolaemic blood induce epigenetically driven down-regulation of endothelial HIF-1α expression in a preclinical animal model

AIMS

High-density lipoproteins (HDLs) are circulating micelles that transport proteins, lipids, and miRNAs. HDL-transported miRNAs (HDL-miRNAs) have lately received attention but their effects on vascular cells are not fully understood. Additionally, whether cardiovascular risk factors affect HDL-miRNAs levels and miRNA transfer to recipient cells remains equally poorly known. Here, we have investigated the changes induced by hypercholesterolaemia on HDL-miRNA levels and its effect on recipient endothelial cells (ECs).

METHODS AND RESULTS

Pigs were kept on a high-fat diet (HC; n = 10) or a normocholesterolaemic chow (NC; n = 10) for 10 days reaching cholesterol levels of 321.0 (229.7-378.5) mg/dL and 74.0 (62.5-80.2) mg/dL, respectively. HDL particles were isolated, purified, and quantified. HDL-miRNA profiling (n = 149 miRNAs) of HC- and NC-HDLs was performed by multipanel qPCR. Cell cultures of porcine aortic ECs were used to determine whether HDL-miRNAs were delivered to ECs. Potential target genes modulated by miRNAs were identified by bioinformatics and candidate miRNAs were validated by molecular analysis. In vivo effects in the coronary arteries of normocholesterolaemic swine administered HC- or NC-HDLs were analysed. Among the HDL-miRNAs, four were found in different amounts in HC- and NC-HDL (P < 0.05). miR-126-5p and -3p and miR-30b-5p (2.7×, 1.7×, and 1.3×, respectively) were found in higher levels and miR-103a-3p and miR-let-7g-5p (-1.6×, -1.4×, respectively) in lower levels in HC-HDL. miR-126-5p and -3p were transferred from HC-HDL to EC (2.5×; P < 0.05), but not from NC-HDL, by a SRB1-mediated mechanism. Bioinformatics revealed that HIF1α was the miR-126 target gene with the highest predictive value, which was accordingly found to be markedly reduced in HC-HDL-treated ECs and in miR126 mimic transfected ECs. In vivo validation confirmed that HIF1α was diminished in the coronary endothelial layer of NC pigs administered HC-HDL vs. those administered NC-HDL (P < 0.05).

CONCLUSION

Hypercholesterolaemia induces changes in the miRNA content of HDL enhancing miR126 and its delivery to ECs with the consequent down-regulation of its target gene HIF1α.

Burning season and vegetation coverage influenced the community-level physiological profile of Mediterranean mixed-mesogean pine forest soils

Knowledge of forest soil ecology is necessary to assess vulnerability to disturbances, such as wildfires, and improve its microbial diversity and functional value. Soil microbiota play an important role in forest soil processes and are a key driver of postfire recovery, but they are very vulnerable to heat. According to future scenarios for climate and land-use change, fire regimes will undergo transformations in semiarid terrestrial ecosystems, mainly in the Mediterranean Basin. To develop tools for forest management in fire-prone areas, i.e., fire prevention, we assessed the impact of prescribed burnings on soil microorganisms in Mediterranean mixed pine forests. We hypothesised that low severity fire burns would not influence the functional diversity of soil microorganisms, although the burning season could influence that response due to seasonal variations in its vulnerability. We used the Biolog EcoPlate System to record soil biological indicators and assess the effect of the prescribed burning season (early or late season) on bacterial communities, including the soil-plant interphase. The soil microbiome response differed significantly according to vegetation coverage but prescribed burning season was not directly related. Burning increased the proportions of soil organic matter and soil organic carbon, and also promoted cation-exchange capacity and total phosphorus, which were higher following spring burns. Microbial richness and the Shannon-Weaver diversity index both showed a positive correlation with vegetation cover. However, microbial richness was triggered after burning uncovered patches of vegetation. We also noted differences in the usage pattern for the six substrate groups defined in our study: the use of carboxylic acids, amino acids and carbohydrates was higher in unburned plots and those subject to late burns, whereas amino acids did not predominate in early burn plots.

Sex differences and emerging new risk factors for atherosclerosis and its thrombotic complications

Cardiovascular disease (CVD) stays as the world's leading cause of death and disability in both men and women, but with different prognostic and outcome between sexes. Although the burden of CVD is generally related to the conventional risk factors, the relevance of non-traditional risk factors is increasingly recognized to explain the so-called "residual risk". Men and women share many similarities regarding classical cardiovascular risk factors, but have different disease pathophysiology, clinical presentations, prevalence and outcome of CVD. How sex-specificities regarding effects of nontraditional risk factors may contribute to the evolution of atherosclerosis and its clinical manifestations in male and female remain largely under-analyzed. The present review summarizes the current knowledge for sex differences in atherosclerotic plaque composition and clinical evolution in association to risk factors such as inflammation, lipoprotein(a), haemostasis, intraplaque calcification and depression. We further discuss the potential sex-differential impact of chronic infectious diseases, gut microbiome and, epigenetic gene expression regulation for atherosclerosis and the effect of female-specific disorders in CVD.

PCSK9 and LRP5 in macrophage lipid internalization and inflammation

AIMS

Atherosclerosis, the leading cause of cardiovascular diseases, is driven by high blood cholesterol levels and chronic inflammation. Low-density lipoprotein receptors (LDLR) play a critical role in regulating blood cholesterol levels by binding to and clearing LDLs from the circulation. The disruption of the interaction between proprotein convertase subtilisin/kexin 9 (PCSK9) and LDLR reduces blood cholesterol levels. It is not well known whether other members of the LDLR superfamily may be targets of PCSK9. The aim of this work was to determine if LDLR-related protein 5 (LRP5) is a PCSK9 target and to study the role of PCSK9 and LRP5 in foam cell formation and lipid accumulation.

METHODS AND RESULTS

Primary cultures of human inflammatory cells (monocytes and macrophages) were silenced for LRP5 or PCSK9 and challenged with LDLs. We first show that LRP5 is needed for macrophage lipid uptake since LRP5-silenced macrophages show less intracellular CE accumulation. In macrophages, internalization of LRP5-bound LDL is already highly evident after 5 h of LDL incubation and lasts up to 24 h; however, in the absence of both LRP5 and PCSK9, there is a strong reduction of CE accumulation indicating a role for both proteins in lipid uptake. Immunoprecipitation experiments show that LRP5 forms a complex with PCSK9 in lipid-loaded macrophages. Finally, PCSK9 participates in TLR4/NFkB signalling; a decreased TLR4 protein expression levels and a decreased nuclear translocation of NFκB were detected in PCSK9 silenced cells after lipid loading, indicating a downregulation of the TLR4/NFκB pathway.

CONCLUSION

Our results show that both LRP5 and PCSK9 participate in lipid uptake in macrophages. In the absence of LRP5, there is a reduced release of PCSK9 indicating that LRP5 also participates in the mechanism of release of soluble PCSK9. Furthermore, PCSK9 up-regulates TLR4/NFκB favouring inflammation.

HDL (High-Density Lipoprotein) Remodeling and Magnetic Resonance Imaging-Assessed Atherosclerotic Plaque Burden: Study in a Preclinical Experimental Model

OBJECTIVE

HDL (high-density lipoprotein) role in atherosclerosis is controversial. Clinical trials with CETP (cholesterylester transfer protein)-inhibitors have not provided benefit. We have shown that HDL remodeling in hypercholesterolemia reduces HDL cardioprotective potential. We aimed to assess whether hypercholesterolemia affects HDL-induced atherosclerotic plaque regression. Approach and Results: Atherosclerosis was induced in New Zealand White rabbits for 3-months by combining a high-fat-diet and double-balloon aortic denudation. Then, animals underwent magnetic resonance imaging (basal plaque) and randomized to receive 4 IV infusions (1 infusion/wk) of HDL isolated from normocholesterolemic (NC-HDL; 75 mg/kg; n=10), hypercholesterolemic (HC-HDL; 75 mg/Kg; n=10), or vehicle (n=10) rabbits. Then, animals underwent a second magnetic resonance imaging (end plaque). Blood, aorta, and liver samples were obtained for analyses. Follow-up magnetic resonance imaging revealed that NC-HDL administration regressed atherosclerotic lesions by 4.3%, whereas, conversely, the administration of HC-HDLs induced a further 6.5% progression (P<0.05 versus basal). Plaque characterization showed that HC-HDL administered animals had a 2-fold higher lipid and cholesterol content versus those infused NC-HDL and vehicle (P<0.05). No differences were observed among groups in CD31 levels, nor in infiltrated macrophages or smooth muscle cells. Plaques from HC-HDL administered animals exhibited higher Casp3 (caspase 3) content (P<0.05 versus vehicle and NC-HDL) whereas plaques from NC-HDL infused animals showed lower expression of Casp3, Cox1 (cyclooxygenase 1), inducible nitric oxide synthase, and MMP (metalloproteinase) activity (P<0.05 versus HC-HDL and vehicle). HDLs isolated from animals administered HC-HDL displayed lower antioxidant potential and cholesterol efflux capacity as compared with HDLs isolated from NC-HDL-infused animal and vehicle or donor HDL (P<0.05). There were no differences in HDL-ApoA1 content, ABCA1 (ATP-binding cassette transporter A1) vascular expression, and SRB1 (scavenger receptor B1) and ABCA1 liver expression.

CONCLUSIONS

HDL particles isolated from a hypercholesterolemic milieu lose their ability to regress and stabilize atherosclerotic lesions. Our data suggest that HDL remodeling in patients with co-morbidities may lead to the loss of HDL atheroprotective functions.

Role of Autophagy in Von Willebrand Factor Secretion by Endothelial Cells and in the In Vivo Thrombin-Antithrombin Complex Formation Promoted by the HIV-1 Matrix Protein p17

Although the advent of combined antiretroviral therapy has substantially improved the survival of HIV-1-infected individuals, non-AIDS-related diseases are becoming increasingly prevalent in HIV-1-infected patients. Persistent abnormalities in coagulation appear to contribute to excess risk for a broad spectrum of non-AIDS defining complications. Alterations in coagulation biology in the context of HIV infection seem to be largely a consequence of a chronically inflammatory microenvironment leading to endothelial cell (EC) dysfunction. A possible direct role of HIV-1 proteins in sustaining EC dysfunction has been postulated but not yet investigated. The HIV-1 matrix protein p17 (p17) is secreted from HIV-1-infected cells and is known to sustain inflammatory processes by activating ECs. The aim of this study was to investigate the possibility that p17-driven stimulation of human ECs is associated with increased production of critical coagulation factors. Here we show the involvement of autophagy in the p17-induced accumulation and secretion of von Willebrand factor (vWF) by ECs. In vivo experiments confirmed the capability of p17 to exert a potent pro-coagulant activity soon after its intravenous administration.

MicroRNA-145 Regulates the Differentiation of Adipose Stem Cells Toward Microvascular Endothelial Cells and Promotes Angiogenesis

RATIONALE

Adipose-derived stem cells (ASCs) are a potential adult mesenchymal stem cell source for restoring endothelial function in ischemic tissues. However, the mechanism that promotes ASCs differentiation toward endothelial cells (ECs) is not known.

OBJECTIVE

To investigate the mechanisms of ASCs differentiation into ECs.

METHODS AND RESULTS

ASCs were isolated from clinical lipoaspirates and cultured with DMEM or endothelial cell-conditioned medium. Endothelial cell-conditioned medium induced downregulation of miR-145 in ASCs and promoted endothelial differentiation. We identified bFGF (basic fibroblast growth factor) released by ECs as inducer of ASCs differentiation through receptor-induced AKT (protein kinase B) signaling and phosphorylation of FOXO1 (forkhead box protein O1) suppressing its transcriptional activity and decreasing miR-145 expression. Blocking bFGF-receptor or PI3K/AKT signaling in ASCs increased miR-145 levels. Modulation of miR-145 in ASCs, using a miR-145 inhibitor, regulated their differentiation into ECs: increasing proliferation, migration, inducing expression of EC markers (VE-cadherin, VEGFR2 [vascular endothelial growth factor receptor 2], or VWF [von Willebrand Factor]), and tube-like formation. Furthermore, in vivo, downregulation of miR-145 in ASCs enhanced angiogenesis in subcutaneously implanted plugs in mice. In a murine hindlimb ischemia model injection of ASCs with downregulated miR-145 induced collateral flow and capillary formation evidenced by magnetic resonance angiography. Next, we identified ETS1 (v-ets avian erythroblastosis virus E26 oncogene homolog 1) as the target of miR-145. Upregulation of miR-145 in ASCs, by mimic miR-145, suppressed ETS1 expression and consequently abolished EC differentiation and the angiogenic properties of endothelial cell-conditioned medium-preconditioned ASCs; whereas, overexpression of ETS1 reversed the abrogated antiangiogenic capacity of miR-145. ETS1 overexpression induced similar results to those obtained with miR-145 knockdown.

CONCLUSIONS

bFGF released by ECs induces ASCs differentiation toward ECs through miR-145-regulated expression of ETS1. Downregulation of miR-145 in ASCs induce vascular network formation in ischemic muscle.

Estimating Concentration Response Function and Change-Point using Time-Course and Calibration Data

In this paper the problem of determining the functional relationship between time and the concentration of a chemical substance is studied. An intervention drug is administered on the experimental unit from which the chemical substance (specimen) is measured. This drug is hypothesized to cause a change in the concentration level of the chemical substance a certain lag-time after the intervention. However, the concentration value could not be directly measured, but rather a surrogate response can be measured. In the time-course study, this surrogate response is measured using different electrodes which possess varied behaviors. To utilize these surrogate measurements arising from the different electrodes (sensors), a calibration study is undertaken which measures the surrogate response for the different electrodes at known concentration levels. Based on the time-course and calibration data sets, a statistical procedure to estimate the signal function and the lag-time is proposed. Simulation studies indicate that the proposed procedure is able to reasonably recover the signal function and the lag-time. The procedure is then applied to the real data sets obtained during an analytical chemistry experiment.

Silybum marianum provides cardioprotection and limits adverse remodeling post-myocardial infarction by mitigating oxidative stress and reactive fibrosis

AIMS

Milk thistle (Silybum marianum; SM) is an herb commonly used for hepatoprotection with antioxidant and antifibrotic properties. We investigated in pigs the cardiac effects of SM intake during the acute phase of myocardial infarction (MI) and remodeling period post-MI.

METHODS

Study-1 tested the effect of SM use on the acute phase of MI. Hence, animals were distributed to a control group or to receive SM prior infarction (1.5 h ischemia). Animals were sacrificed after 2.5 h of reperfusion. Study-2 tested the effect of SM use in the cardiac remodeling phase. Accordingly, animals received for 10 d diet ± SM prior MI and followed the same regime for 3 weeks and then sacrificed. Study-3 tested the effect of SM in a non-infarcted heart; therefore, animals received for 10 d diet ± SM and then sacrificed.

RESULTS

Animals taking SM before MI showed a reduction in cardiac damage (decreased oxidative damage, ROS production and xanthine oxidase levels; preserved mitochondrial function; and increased myocardial salvage; p < 0.05) versus controls. Animals that remained on chronic SM intake post-MI improved left ventricular remodeling. This was associated with the attenuation of the TGFß1/TßRs/SMAD2/3 signaling, lower myofibroblast transdifferentiation and collagen content in the border zone (p < 0.05 vs. all other groups). Cardiac contractility improved in animals taking SM (p < 0.05 vs. post-MI-control). No changes in cardiac function or fibrosis were detected in animals on SM but without MI.

CONCLUSION

Intake of SM protects the heart against the deleterious effects of an MI and favors cardiac healing. These benefits may be attributed to the antioxidant and antifibrotic properties of SM.

C-Reactive Protein in Atherothrombosis and Angiogenesis

C-reactive protein (CRP) is a short pentraxin mainly found as a pentamer in the circulation, or as non-soluble monomers CRP (mCRP) in tissues, exerting different functions. This review is focused on discussing the role of CRP in cardiovascular disease, including recent advances on the implication of CRP and its forms specifically on the pathogenesis of atherothrombosis and angiogenesis. Besides its role in the humoral innate immune response, CRP contributes to cardiovascular disease progression by recognizing and binding multiple intrinsic ligands. mCRP is not present in the healthy vessel wall but it becomes detectable in the early stages of atherogenesis and accumulates during the progression of atherosclerosis. CRP inhibits endothelial nitric oxide production and contributes to plaque instability by increasing endothelial cell adhesion molecules expression, by promoting monocyte recruitment into the atheromatous plaque and by enzymatically binding to modified low-density lipoprotein. CRP also contributes to thrombosis, but depending on its form it elicits different actions. Pentameric CRP has no involvement in thrombogenesis, whereas mCRP induces platelet activation and thrombus growth. In addition, mCRP has apparently contradictory pro-angiogenic and anti-angiogenic effects determining tissue remodeling in the atherosclerotic plaque and in infarcted tissues. Overall, CRP contributes to cardiovascular disease by several mechanisms that deserve an in-depth analysis.

Microvesicles in Atherosclerosis and Angiogenesis: From Bench to Bedside and Reverse

Atherosclerosis (AT) is a progressive chronic disease involving lipid accumulation, fibrosis, and inflammation in medium and large-sized arteries, and it is the main cause of cardiovascular disease (CVD). AT is caused by dyslipidemia and mediated by both innate and adaptive immune responses. Despite lipid-lowering drugs have shown to decrease the risk of cardiovascular events (CVEs), there is a significant burden of AT-related morbidity and mortality. Identification of subjects at increased risk for CVE as well as discovery of novel therapeutic targets for improved treatment strategies are still unmet clinical needs in CVD. Microvesicles (MVs), small extracellular plasma membrane particles shed by activated and apoptotic cells have been widely linked to the development of CVD. MVs from vascular and resident cells by facilitating exchange of biological information between neighboring cells serve as cellular effectors in the bloodstream and play a key role in all stages of disease progression. This article reviews the current knowledge on the role of MVs in AT and CVD. Attention is focused on novel aspects of MV-mediated regulatory mechanisms from endothelial dysfunction, vascular wall inflammation, oxidative stress, and apoptosis to coagulation and thrombosis in the progression and development of atherothrombosis. MV contribution to vascular remodeling is also discussed, with a particular emphasis on the effect of MVs on the crosstalk between endothelial cells and smooth muscle cells, and their role regulating the active process of AT-driven angiogenesis and neovascularization. This review also highlights the latest findings and main challenges on the potential prognostic, diagnostic, and therapeutic value of cell-derived MVs in CVD. In summary, MVs have emerged as new regulators of biological functions in atherothrombosis and might be instrumental in cardiovascular precision medicine; however, significant efforts are still needed to translate into clinics the latest findings on MV regulation and function.