ITGB2 is a central hub-gene associated with inflammation and early fibro-atheroma development in a swine model of atherosclerosis

Background and aim

The complex dynamic interplay between different biological pathways involved in atherosclerosis development has rendered the identification of specific therapeutic targets a challenging quest. We aimed to identify specific genes and mechanistic pathways associated with the early development of fibro-atheromas in a swine model of atherosclerosis.

Methods

The Wisconsin Miniature Swine™ model of Familial Hypercholesterolemia (WMS-FH, n = 11) and genetically related WMS controls (WMS-N, n = 11) were used. The infrarenal aorta was harvested from both groups for histopathologic and transcriptomic profiling at 12 months. Bioinformatic analysis was performed to identify hub genes and pathways central to disease pathophysiology. The expression of ITGB2, the top ranked hub gene, was manipulated in cell culture and the expression of interconnected genes was tested.

Results

Fibro-atheromatous lesions were documented in all WMS-FH aortic tissues and displayed internal elastic lamina (IEL) disruption, significant reduction of myofibroblast presence and disorganized collagen deposition. No fibro-atheromas were observed in the control group. A total of 266 differentially expressed genes (DEGs) were upregulated in WMS-FH aortic tissues, while 29 genes were downregulated. Top identified hub genes included ITGB2, C1QA, LCP2, SPI1, CSF1R, C5AR1, CTSS, MPEG1, C1QC, and CSF2RB. Overexpression of ITGB2 resulted in elevated expression of other interconnected genes expressed in porcine endothelial cells.

Conclusion

In a swine translational model of atherosclerosis, transcriptomic analysis identified ITGB2 as a central hub gene associated inflammation and early fibroatheroma development making it a potential therapeutic target at this stage of disease.

Longitudinal dynamics of circulating miRNAs in a swine model of familial hypercholesterolemia during early atherosclerosis

Atherosclerosis is a complex progressive disease involving intertwined biological mechanisms. We aimed to identify miRNA expression dynamics at the early stages of atherosclerosis using a large swine model (Wisconsin Miniature Swine, WMS). A total of 18 female pigs; 9 familial hypercholesterolemic (WMS-FH) and 9 normal control swine (WMS-N) were studied. miRNA sequencing was performed on plasma cell-free RNA at 3, 6, and 9 months of age. RT-qPCR validated DE miRNAs in a new cohort of animals (n = 30) with both sexes. Gene ontology and mRNA targets for DE miRNAs were identified. In vivo multimodality imaging and histopathology were performed to document the presence of atherosclerosis at termination. 20, 19, and 9 miRNAs were significantly DE between the groups at months 3, 6, and 9, respectively. Most DE miRNAs and their target genes are involved in human atherosclerosis development. Coronary atherosclerosis was documented in 7/9 WMS-FH pigs. Control animals had no lesions. miR-138, miR-152, miR-190a, and miR-196a showed a significant diagnostic power at month 3, whereas miR-486, miR-126-3p, miR-335, and miR-423-5p were of significant diagnostic power at month 9. In conclusion, specific DE miRNAs with significant discriminatory power may be promising biomarkers for the early detection of coronary atherosclerosis.

Design and construction of three-dimensional physiologically-based vascular branching networks for respiratory assist devices

Microfluidic lab-on-a-chip devices are changing the way that in vitro diagnostics and drug development are conducted, based on the increased precision, miniaturization and efficiency of these systems relative to prior methods. However, the full potential of microfluidics as a platform for therapeutic medical devices such as extracorporeal organ support has not been realized, in part due to limitations in the ability to scale current designs and fabrication techniques toward clinically relevant rates of blood flow. Here we report on a method for designing and fabricating microfluidic devices supporting blood flow rates per layer greater than 10 mL min^-1 for respiratory support applications, leveraging advances in precision machining to generate fully three-dimensional physiologically-based branching microchannel networks. The ability of precision machining to create molds with rounded features and smoothly varying channel widths and depths distinguishes the geometry of the microchannel networks described here from all previous reports of microfluidic respiratory assist devices, regarding the ability to mimic vascular blood flow patterns. These devices have been assembled and tested in the laboratory using whole bovine or porcine blood, and in a porcine model to demonstrate efficient gas transfer, blood flow and pressure stability over periods of several hours. This new approach to fabricating and scaling microfluidic devices has the potential to address wide applications in critical care for end-stage organ failure and acute illnesses stemming from respiratory viral infections, traumatic injuries and sepsis.

Waste marble dust and recycled glass valorization in the production of ternary blended cements

The purpose of the present investigation is to examine the physicomechanical properties and the hydration development of ternary blended cements, composed by waste marble dust (WMD) and soda lime recycled glass (SLRG). Both wastes characteristics were investigated by means of chemical analysis, laser particle size analyzer and X-ray diffraction (XRD). Prior to their addition as substitutes for Ordinary Portland Cement (OPC), they were grounded to a specific surface area of 4000 cm²/g. Twelve different cement mixtures were produced, containing up to 20% of the above-mentioned wastes, in various proportions. The produced cements mixtures were evaluated, examining their setting times, standard consistency, soundness and compressive strength at 2, 7, 28, 56 and 90 days. The resistance to the alkali-silica reaction of the cement mixtures contained SLRG and the corresponding expansion was determined in prismatic mortar bars, at 38 °C, after 14, 28, 60, 90 and 180 days. The determination of their hydration evolution was accomplished by X-ray diffraction and thermogravimetric and differential thermal (TG/DTG) analyses. According to the results, WMD could be readily valorized together with SLRG as cementitious additions for cement replacement.

Preclinical in vivo long-term evaluation of the novel Mitra-Spacer technology: experimental validation in the ovine model

AIMS

The Mitra-Spacer (Cardiosolutions, Bridgewater, MA, USA) is designed to treat mitral regurgitation by introducing a dynamic spacer that constantly adapts to the changing haemodynamic conditions during the cardiac cycle. We aimed to evaluate the performance and safety of this device in the chronic ovine model.

METHODS AND RESULTS

Eight sheep were enrolled in this study. Through a left thoracotomy, the Mitra-Spacer was inserted via the transapical approach and advanced into the left atrium (LA) under imaging guidance. Device performance and safety were evaluated up to 90 days using fluoroscopy, echocardiography and histopathology. The volume within the balloon spacer shifted during the cardiac cycle in all cases. Seven animals survived up to 90 days for terminal imaging and tissue harvest. Echocardiography showed no change in left ventricle (LV) ejection fraction from baseline to 90 days. There were no observations of changes in LV diastolic function, pulmonary vein inflow, or tricuspid valve function. Histological analysis demonstrated no significant injury to the mitral apparatus.

CONCLUSIONS

In the healthy ovine model, Mitra-Spacer implantation was feasible and safe. At 90 days, no evidence of structural damage to the mitral apparatus or deterioration of cardiac performance was demonstrated.

Stenting and Adjunctive Delivery of Paclitaxel Via Balloon Coating Versus Durable Polymeric Matrix for De Novo Coronary Lesions: Clinical and Angiographic Results from the Prospective Randomized Trial

BACKGROUND

There is limited comparative clinical data regarding the safety and efficacy profile of paclitaxel delivery via balloon versus stent-polymer matrix. In this study, we aimed to compare the clinical and angiographic results of two different methods of paclitaxel delivery among patients undergoing percutaneous coronary intervention (PCI) for single de novo coronary lesions.

METHODS

A total of 202 patients undergoing PCI due to symptomatic heart disease and at least one significant coronary artery lesion were prospectively enrolled in a multicenter non-inferiority trial. Eligible patients were randomized to a revascularization with either a paclitaxel eluting stent (PES = Coroflex Please, B.Braun) or a bare metal stent (BMS) followed by a paclitaxel coated balloon (PCB) dilation (BMS = Coroflex + PCB = Sequent Please, B.Braun). Clinical follow-up was obtained at 9 months in all patients, whereas angiographic in a subset of 94 (46.5%) patients.

RESULTS

The baseline characteristics were well balanced between groups. At 9 months, the primary endpoint of in-stent late lumen loss in BMS + PCB was comparable and non-inferior to PES (0.21 ± 0.5 vs. 0.30 ± 0.7 mm, respectively. P(non-inf)  < 0.05). At 9 months, the incidence of MACE (7.0 vs. 6.9%, HR = 1, 95%CI: 0.3-2.8; P = 0.99), comprising the occurrence of myocardial infarction (4.9 vs. 3.0%, HR = 1.62, 95%CI: 0.4-6.5; P = 0.32), target lesion revascularization (6.9 vs. 5.0%, HR = 1.42, 95%CI: 0.4-4.4; p = 0.54) and stent thrombosis (4.9 vs. 3.0%, HR = 2.01, 95%CI: 0.5-7.4; P = 0.74) was comparable between BMS + PCB and PES, respectively. In the BMS + PCB group, thrombosis tended to occur within 30 days (3.9 vs. 1.0%; P = 0.38).

CONCLUSIONS

Paclitaxel delivery via drug coated balloon or polymer-stent matrix achieved comparable angiographic and clinical results among patients with de novo coronary lesions. BMS + PCB revascularization was associated with a higher rate of stent thrombosis when compared to newer generation drug eluting stents, therefore, should be recommended as a bail-out for PCB alone angioplasty.

Early feasibility evaluation of thoracoscopically assisted transcatheter ventricular reconstruction in an experimental model of ischaemic heart failure with left anteroapical aneurysm

AIMS

To test the feasibility of a thoracoscopically assisted, off-pump, transcatheter ventricular reconstruction (TCVR) approach in an ovine model of left ventricular (LV) anteroapical aneurysm.

METHODS AND RESULTS

Myocardial infarction (MI) was induced by coil occlusion of the middle left anterior descending artery and diagonals. Two months after MI creation, TCVR was performed via a minimal thoracotomy in eight sheep. Under endoscopic and fluoroscopic guidance, trans-interventricular septal puncture was performed from the LV epicardial scar. A guidewire was externalised via a snare placed in the right ventricle from the external jugular vein. An internal anchor was inserted over the wire and positioned on the right ventricular septum and an external anchor was deployed on the LV anterior epicardium. Serial pairs of anchors were placed and plicated together to exclude the scar completely. Immediately after TCVR, echocardiography showed LV end-systolic volume decreased from pre-procedure 58.8±16.6 ml to 25.1±7.6 ml (p<0.01) and the ejection fraction increased from 32.0±7.3% to 52.0±7.5% (p<0.01). LV twist significantly improved (3.83±2.21 vs. pre-procedure -0.41±0.94, p=0.01) and the global peak-systolic longitudinal strain increased from -5.64% to -10.77% (p<0.05).

CONCLUSIONS

TCVR using minimally invasive access techniques on the off-pump beating heart is feasible and resulted in significant improvement in LV performance.

Comparable clinical safety and efficacy of biodegradable versus durable polymer paclitaxel eluting stents despite shorter dual antiplatelet therapy: insights from a multicenter, propensity score-matched registry

BACKGROUND

The biodegradable polymer drug-eluting stents have been proposed as an alternative to durable polymer DES, theoretically improving vessel healing and reducing the need for prolonged double anti platelet therapy (DAPT), however clinical significance of this technology is under debate. Therefore, we sought to compare the clinical outcomes of two Paclitaxel eluting stents (PES) containing different polymer-based eluting matrices.

METHODS

In this multicenter registry of 392 consecutive patients who underwent PCI between June 2006 and September 2008, we included patients with stable angina or NSTE-ACS displaying at least one significant lesion (>50% diameter stenosis) in native coronary arteries.

RESULTS

Biodegradable polymer PES (BP-PES, LUC Chopin(2) , Balton, Poland) was implanted in 206 patients, whereas durable polymer PES (DP-PES, Taxus, Boston Scientific, USA) was implanted in 186 patients. There were no significant differences in baseline characteristics between groups with the exception of increased diabetes and number of lesions for BP-PES. In risk-unadjusted analysis at 1-year follow-up, there were no significant differences in TLR (BP-PES: 8.4% vs.

DP-PES

6%; P = 0.36), TVR (BP-PES: 11.1% vs.

DP-PES

8.4%; P = 0.36) and incidence of stent thromboses (BP-PES: 2.15% vs.

DP-PES

3.4%; P = 0.42) between groups. There was also no difference in MACCE between groups (17.6% vs. 14.4%, P = 0.49). The mean dual antiplatelet therapy (DAPT) compliance at 1 year was 77% for BP-PES versus 92% for DP-PES (P = 0.03). Kaplan-Meier analysis showed a significantly higher long-term stroke free survival in BP-PES (P = 0.04). After adjustment, this was sustained with an additional tendency toward higher MI free survival for BP-PES (P = 0.059).

CONCLUSIONS

In this observational analysis, BP-PES were comparable to DP-PES, with regard to incidence of repeated revascularizations, stent thromboses and MACCE despite earlier DAPT discontinuation.

Mechanism of gender-specific differences in aortic stiffness with aging in nonhuman primates

BACKGROUND

Our hypothesis was that the changes in vascular properties responsible for aortic stiffness with aging would be greater in old male monkeys than old female monkeys.

METHODS AND RESULTS

We analyzed the effects of gender differences in aging on in vivo measurements of aortic pressure and diameter and on extracellular matrix of the thoracic aorta in young adult (age, 6.6+/-0.5 years) versus old adult (age, 21.2+/-0.2 years) monkeys (Macaca fascicularis). Aortic stiffness, as represented by the pressure strain elastic modulus (Ep), increased more in old male monkeys (5.08+/-0.81; P<0.01) than in old females (3.06+/-0.52). In both genders, collagen density was maintained, collagen-bound glycation end products increased, and collagen type 1 decreased. However, elastin density decreased significantly (from 22+/-1.5% to 15+/-1.2%) with aging (P<0.05) only in males. Furthermore, only old males were characterized by a decrease (P<0.05) in collagen type 3 (an isoform that promotes elasticity) and an increase in collagen type 8 (an isoform that promotes the neointimal migration of vascular smooth muscle cells). In contrast to the data in monkeys, collagen types 1 and 3 both increased significantly in aging rats.

CONCLUSIONS

There are major species differences in the effects of aging on aortic collagen types 1 and 3. Furthermore, because alterations in collagen density, collagen content, hydroxyproline, and collagen advanced glycation end products were similar in both old male and female monkeys, these factors cannot be responsible for the greater increase in stiffness in old males. However, changes in collagen isoforms and the decrease in elastin observed only in old males likely account for the greater increase in aortic stiffness.

Increased apoptosis and myocyte enlargement with decreased cardiac mass; distinctive features of the aging male, but not female, monkey heart

We studied gender-specific changes in aging cardiomyopathy in a primate model, Macaca fascicularis, free of the major human diseases, complicating the interpretation of data specific to aging in humans. Left ventricular (LV) weight/body weight decreased, p<0.05, in old males but did not change in old females. However, despite the decrease in LV weight, mean myocyte cross-sectional area in the old males increased by 51%. This increase in myocyte size was not uniform in old males, i.e., it was manifest in only 20-30% of all the myocytes from old males. In old males there was a 4-fold increase in frequency of myocyte apoptosis without any increase in proliferation-capable myocytes assessed by Ki-67 expression. Apoptosis was unchanged in old female monkey hearts, whereas the frequency of myocytes expressing Ki-67 declined 90%. These results, opposite to findings from rodent studies, indicate distinct differences in which male and female monkeys maintain functional heart mass during aging. The old male hearts demonstrated increased apoptosis, which more than offset the myocyte hypertrophy. Interestingly, the hypertrophy was not uniform and there was no significant increase in myocyte proliferation.

Sex-specific regulation of gene expression in the aging monkey aorta

Although increased vascular stiffness is more prominent in aging males than females, and males are more prone to vascular disease with aging, no study has investigated the genes potentially responsible for sex differences in vascular aging. We tested the hypothesis that the transcriptional adaptation to aging differs in males and females using a monkey model, which is not only physiologically and phylogenetically closer to humans than the more commonly studied rodent models but also is not afflicted with the most common forms of vascular disease that accompany the aging process in humans, e.g., atherosclerosis, hypertension, and diabetes. The transcriptional profile of the aorta was compared by high-density microarrays between young and old males or females ( n = 6/group). About 600 genes were expressed differentially when comparing old versus young animals. Surprisingly, <5% of these genes were shared between males and females. Radical differences between sexes were especially apparent for genes regulating the extracellular matrix, which relates to stiffness. Aging males were also more prone than females to genes switching smooth muscle cells from the “contractile” to “secretory” phenotype. Other sex differences involved genes participating in DNA repair, stress response, and cell signaling. Therefore, major differences of gene regulation exist between males and females in vascular aging, which may underlie the physiological differences characterizing aging arteries in males and females. Furthermore, the analyses in young monkeys demonstrated differences in genes regulating vascular structure, implying that the sex differences in vascular stiffness that develop with aging are programmed at an early age.

Gender differences on the effects of aging on cardiac and peripheral adrenergic stimulation in old conscious monkeys

We examined the effects of gender and aging on cardiac and peripheral hemodynamic responses to beta-adrenergic receptor (beta-AR) stimulation in young (male = 5.9 +/- 0.4 yr old and female = 6.5 +/- 0.7 yr old) and old (male = 19.8 +/- 0.7 yr old and female = 21.2 +/- 0.2 yr old) conscious monkeys (Macaca fascicularis), chronically instrumented for measurements of left ventricular (LV) and arterial pressures as well as cardiac output. Baseline LV pressure, the first derivative of LV pressure (LV dP/dt), cardiac index, mean arterial pressure, total peripheral resistance (TPR), and heart rate in conscious monkeys were not different among the four groups. Increases in LV dP/dt in response to 0.1 microg/kg isoproterenol (Iso) were diminished (P < 0.05) in old males (+99 +/- 11%) compared with young males (+194 +/- 18%). In addition, the inotropic responses to norepinephrine (NE) and forskolin (FSK) were significantly depressed (P < 0.05) in old males. Iso-induced reductions of TPR were less (P < 0.05) in old males (-28 +/- 2%) than in young males (-49 +/- 2%). The changes of TPR in response to NE and FSK were also significantly attenuated (P < 0.05) in old males. However, the LV dP/dt responses to BAY y 5959 (15 microg. kg-1. min-1), a Ca2+ channel promotor independent of beta-AR signaling, were not significantly different between old and young males. In contrast to results in male monkeys, LV dP/dt and TPR responses to Iso, NE, and FSK in old females were similar to those observed in young females. Thus both cardiac contractile and peripheral vascular dynamic responses to beta-AR stimulation are preserved in old female but not old male monkeys. This may explain, in part, the reduced cardiovascular risk in the older female population.

Persistent stunning induces myocardial hibernation and protection: flow/function and metabolic mechanisms

To test the hypothesis that persistent myocardial stunning can lead to hibernating myocardium, 13 pigs were chronically instrumented, and persistent stunning was induced regionally by 6 repetitive episodes of 90-minute coronary stenosis (CS) (30% reduction in baseline coronary blood flow [CBF]) followed by full reperfusion every 12 hours. During the 1st CS, CBF fell from 43+/-2 to 31+/-2 mL/min, and anterior wall thickening (AWT) fell by 54+/-8%, but posterior WT did not change. AWT never recovered fully and remained depressed by 31+/-7% before the 6th CS, reflecting persistent myocardial stunning, but baseline CBF was not changed. Surprisingly, during the 6th CS, AWT did not fall further despite a similar reduction in CBF during CS, as occurred with the 1st episode. Regional Mo2 fell similarly during the 1st and 6th CS. During the 1st CS, plasma glucose uptake increased, whereas free fatty acid (FFA) uptake was reduced. Before the 6th CS, glucose uptake remained elevated, whereas FFA uptake remained reduced. Histology revealed enhanced glycogen deposition, which could be explained by decreased glycogen synthase kinase (GSK)-3beta protein levels and activity. These results indicate that persistent stunning, even in the absence of chronic ischemia, can recapitulate the phenotype of myocardial hibernation. This results in a shift in the flow/function relationship where a 30% decrease in CBF is no longer accompanied by a fall in myocardial function, which could be explained, in part, by a shift in substrate utilization. These hemodynamic/metabolic adjustments could facilitate survival of hibernating myocardium.