Vasa Vasorum Density Research Articles

Influence of nonalcoholic fatty liver disease severity on carotid adventitial vasa vasorum.

Nonalcoholic fatty liver disease (NAFLD) affects a quarter of the world's population and encompasses a spectrum of liver conditions, from non-alcoholic steatohepatitis (NASH) to inflammation and fibrosis. In addition, NAFLD also links to extrahepatic conditions like diabetes or obesity. However, it remains unclear if NAFLD independently correlates with the onset and progression of atherosclerosis. This cross-sectional study aimed to explore the relationship between NAFLD severity, assessed via liver biopsy, and early atherosclerosis using adventitial vasa vasorum (VV) density. It included 44 patients with obesity (33 with steatosis, 11 with NASH) undergoing bariatric surgery. Results revealed no significant differences in adventitial VV density between steatosis and NASH groups, neither in the mean values [0.759 ± 0.104 vs. 0.780 ± 0.043, P=0.702] nor left-right sides. Similarly, carotid intima-media thickness (cIMT) did not vary between these groups. Additionally, no linear correlation existed between VV density and cIMT. Only gender showed an association with VV density. These findings suggest that NASH severity doesn't independently drive early atherosclerosis or affects cIMT. Gender might play a role in early atherosclerotic disease in NAFLD, impacting VV density and cIMT. This highlights the need to consider other risk factors when evaluating cardiovascular risk in NAFLD patients.

Novel treatment from a botanical formulation Si-Miao-Yong-an decoction inhibits vasa vasorum angiogenesis and stabilizes atherosclerosis plaques via the Wnt1/β-catenin signalling pathway

Context Si-Miao-Yong-An (SMYA) has been widely used for the clinical treatment of atherosclerosis (AS). Yet, its complete mechanism of action is not fully understood. Objective To investigate the mechanism by which SMYA stabilizes AS plaques from the perspective of inhibiting vasa vasorum (VV) angiogenesis. Materials and methods We used male ApoE-/- mice to establish an AS model. The mice were divided into model, SMYA (11.7 mg/kg/d), and simvastatin (SVTT) (2.6 mg/kg/d) groups. Mice were given SMYA or SVTT by daily gavage for 8 weeks. HE staining, immunofluorescence double-labelling staining, and immunohistochemical staining were used to observe the pathological changes in the plaques. Finally, the protein and mRNA expression levels of the Wnt1/β-catenin signalling pathway were detected by Western blot and qRT-PCR, respectively. Results SMYA significantly attenuated cholesterol crystallization, and lipid accumulation in AS plaques, resulting in smaller plaque size (0.25 mm2 vs. 0.46 mm2), and lowering ratio of plaque to lumen area (20.04% vs. 38.33%) and VV density (50.64/mm2 vs. 98.02/mm2). Meanwhile, SMYA suppressed both the positive area percentage of Wnt1 (2.53 vs. 3.56), β-catenin (3.33 vs. 5.65) and Cyclin D1 (2.10 vs. 3.27) proteins in the aortic root plaques, and mRNA expression of Wnt1 (1.38 vs. 2.09), β-catenin (2.05 vs. 3.25) and Cyclin D1 (1.39 vs. 2.57). Discussion and conclusions SMYA has a protective effect against AS, which may be related to its anti-VV angiogenesis in plaques, suggesting that SMYA has the potential as a novel botanical formulation in the treatment of AS.

Excessive Adventitial and Perivascular Vascularisation Correlates with Vascular Inflammation and Intimal Hyperplasia.

Albeit multiple studies demonstrated that vasa vasorum (VV) have a crucial importance in vascular pathology, the informative markers and metrics of vascular inflammation defining the development of intimal hyperplasia (IH) have been vaguely studied. Here, we employed two rat models (balloon injury of the abdominal aorta and the same intervention optionally complemented with intravenous injections of calciprotein particles) and a clinical scenario (arterial and venous conduits for coronary artery bypass graft (CABG) surgery) to investigate the pathophysiological interconnections among VV, myeloperoxidase-positive (MPO+) clusters, and IH. We found that the amounts of VV and MPO+ clusters were strongly correlated; further, MPO+ clusters density was significantly associated with balloon-induced IH and increased at calciprotein particle-provoked endothelial dysfunction. Likewise, number and density of VV correlated with IH in bypass grafts for CABG surgery at the pre-intervention stage and were higher in venous conduits which more frequently suffered from IH as compared with arterial grafts. Collectively, our results underline the pathophysiological importance of excessive VV upon the vascular injury or at the exposure to cardiovascular risk factors, highlight MPO+ clusters as an informative marker of adventitial and perivascular inflammation, and propose another mechanistic explanation of a higher long-term patency of arterial grafts upon the CABG surgery.

Pathological Analysis of Vascularization of the Arterialized Veins in Failed Arteriovenous Fistulae

PurposeTo assess venous wall vascularization and its correlation with neointimal hyperplasia (NIH) in failed arteriovenous fistulae (AVFs). Materials and MethodsA total of 43 uremic patients who underwent de novo AVF creation and 39 patients who underwent reconstruction of failed fistulae were enrolled in the study. A 5–10-mm vein segment adjacent to the future fistula creation or reconstruction site was surgically removed and assessed using histopathological analyses and stained by immunohistochemistry to quantify vasa vasorum density (VVD). ResultsBoth the intimal thickness (70.68 [28.81–99.54] vs 4.53 [2.69–7.30] μm, P < .001) and the intimal thickness-to-medial thickness ratio (2.20 [0.77–4.36] vs 0.15 [0.10–0.30], P < .001) were higher in failed AVFs than in preaccess veins. CD31- and factor VIII–marked VVDs in both the intima (6.31 [1.62–12.53] vs 0.0 [0.0–0.0], P < .001; 7.82 [3.33–11.61] vs 0.0 [0.0–0.0], P < .001) and media (10.0 [7.59–12.95] vs 3.71 [2.44–4.87], P < .001; 8.33 [5.55–13.0] vs 3.57 [2.53–4.82], P < .001) as well as the intimal VVD:medial VVD ratio (0.67 [0.19–1.08] vs 0.0 [0.0–0.0], P < .001; 0.71 [0.39–1.14] vs 0.0 [0.0–0.0], P < .001) were significantly higher in failed AVFs than in preaccess veins. Moreover, there was a positive relationship between the intimal VVD:medial VVD ratio and the intimal thickness:medial thickness ratio (P < .001). In addition, the vascular endothelial cell growth factor A expression was higher in failed AVFs than in preaccess veins. ConclusionsVascularization of the vessel wall was noticeably more developed in the arterialized veins, especially at the NIH regions in failed AVFs.

Randomized Clinical Trial to Evaluate the Morphological Changes in the Adventitial Vasa Vasorum Density and Biological Markers of Endothelial Dysfunction in Subjects with Moderate Obesity Undergoing a Very Low-Calorie Ketogenic Diet.

Weight loss after bariatric surgery decreases the earlier expansion of the adventitial vasa vasorum (VV), a biomarker of early atheromatous disease. However, no data are available regarding weight loss achieved by very low calorie ketogenic diets (VLCKD) on VV and lipid-based atherogenic indices. A randomized clinical trial was performed to examine changes in adventitial VV density in 20 patients with moderate obesity who underwent a 6-month very low calorie ketogenic diet (VLCKD, 600–800 kcal/day), and 10 participants with hypocaloric diet based on the Mediterranean Diet (MedDiet, estimated reduction of 500 kcal on the usual intake). Contrast-enhanced carotid ultrasound was used to assess the VV. Body composition analysis was also used. The atherogenic index of plasma (log (triglycerides to high-density lipoprotein cholesterol ratio)) and the triglyceride-glucose index were calculated. Serum concentrations of soluble intercellular adhesion molecule 1 (sICAM-1), and soluble vascular cell adhesion molecule 1 (sVCAM-1) were measured. The impact of weight on quality of life-lite (IWQOL-Lite) questionnaire was administered. Participants of intervention groups displayed a similar VV values. Significant improvements of BMI (−5.3 [−6.9 to −3.6] kg/m2, p < 0.001), total body fat (−7.0 [−10.7 to −3.3] %, p = 0.003), and IWQOL-Lite score (−41.4 [−75.2 to −7.6], p = 0.027) were observed in VLCKD group in comparison with MedDiet group. Although after a 6-months follow-up period VV density (mean, right and left sides) did not change significantly in any group, participants in the VLCKD exhibited a significantly decrease both in their atherogenic index of plasma and serum concentration of sICAM-1. A 6-month intervention with VLCKD do not impact in the density of the adventitial VV in subjects with moderate obesity, but induces significant changes in markers of endothelial dysfunction and CV risk.

Vascular histopathology and connective tissue ultrastructure in spontaneous coronary artery dissection: pathophysiological and clinical implications.

Aims Spontaneous coronary artery dissection (SCAD) is a cause of acute coronary syndromes and in rare cases sudden cardiac death (SCD). Connective tissue abnormalities, coronary inflammation, increased coronary vasa vasorum (VV) density, and coronary fibromuscular dysplasia have all been implicated in the pathophysiology of SCAD but have not previously been systematically assessed. We designed a study to investigate the coronary histological and dermal collagen ultrastructural findings in SCAD.Methods and resultsThirty-six autopsy SCAD cases were compared with 359 SCAD survivors. Coronary and myocardial histology and immunohistochemistry were undertaken. Transmission electron microscopy (TEM) of dermal extracellular matrix (ECM) components of n = 31 SCAD survivors and n = 16 healthy volunteers were compared. Autopsy cases were more likely male (19% vs. 5%; P = 0.0004) with greater proximal left coronary involvement (56% vs. 18%; P < 0.0001) compared to SCAD survivors. N = 24 (66%) of cases showed no myocardial infarction on macro- or microscopic examination consistent with arrhythmogenic death. There was significantly (P < 0.001) higher inflammation in cases with delayed-onset death vs. sudden death and significantly more inflammation surrounding the dissected vs. non-dissected vessel segments. N = 17 (47%) cases showed limited intimal fibro-elastic thickening but no features of fibromuscular dysplasia and no endothelial or internal elastic lamina abnormalities. There were no differences in VV density between SCAD and control cases. TEM revealed no general ultrastructural differences in ECM components or markers of fibroblast metabolic activity.Conclusions Assessment of SCD requires careful exclusion of SCAD, particularly in cases without myocardial necrosis. Peri-coronary inflammation in SCAD is distinct from vasculitides and likely a reaction to, rather than a cause for SCAD. Coronary fibromuscular dysplasia or increased VV density does not appear pathophysiologically important. Dermal connective tissue changes are not common in SCAD survivors.

Effect and Mechanism of Si-Miao-Yong-An on Vasa Vasorum Remodeling in ApoE-/- Mice with Atherosclerosis Vulnerable Plague.

Objective: To observe the effect of Si-Miao-Yong-An (SMYA) on atherosclerosis (AS) vulnerable plaques, and to further explore the mechanism by vasa vasorum (VV) angiogenesis and maturation as an entry point. Methods: SPF-class healthy male ApoE−/− mice were randomized into model group, simvastatin group and SMYA group, and C57BL/6 mice were used as the control group. After 8 weeks of intervention, the pathological morphology of plaque was observed by HE staining; the VV density in plaque and aortic adventitia were observed by immunohistochemistry; VV maturation was measured by double-labelling immunofluorescence; the critical proteins of HIF-1α-Apelin/APJ and Ang-1/Tie signal pathways were detected by western blotting. Results: SMYA decreased the plaque area and the ratio of plaque to lumen area; increased the minimum thickness of fibrous cap and its effect was greater than simvastatin. SMYA suppressed the VV neovascularization; promoted smooth muscle cells recruitment and VV maturation, which maintained plaque stability; its effect was obviously superior to simvastatin. SMYA deceased the expression of HIF-1α, Apelin, APJ, Phospho-MEK1/2 (Ser217/221), Phospho-p44/42 MAPK (Erk1/2) (Thr202/Tyr204), Phospho-p70 S6 Kinase (Thr421/Ser424), Ang-2 and Tie-2; it also increased the expression of Ang-1, Phospho-Akt (Ser473), Phospho-FOXO1 (Ser256) and Survivin. Conclusions: SMYA can decrease the AS plaque area in ApoE−/− mice, suppress the VV neovascularization and promote the VV maturation, and stabilize AS vulnerable plaque. The mechanism could be regulating the HIF-1α-Apelin/APJ and Ang-1/Tie signal pathways.

Clinical implications of coronary artery morphology of patients with ischemia and non-obstructive coronary artery disease (INOCA) -An intracoronary OCT study-

Abstract Introduction Ischemia and non-obstructive coronary artery disease (INOCA), including microvascular spasm (MVS) and epicardial spasm, has recently attracted much attention, for which in vivo imaging evaluation for coronary artery morphology is warranted for better understanding of this disorder. Besides the improved diagnostic accuracy of optical coherence tomography (OCT) for coronary plaques, we have recently demonstrated its capability for in vivo visualization of coronary adventitial vasa vasorum (VV) and the enhanced VV formation in patients with epicardial spasm. Purpose We aimed to examine OCT-delineated morphological characteristics in patients with INOCA in vivo. Methods A total of 335 consecutive INOCA patients, who underwent pharmacological spasm provocation tests, lactate sampling, and OCT imaging over the entire length of the left anterior descending (LAD) coronary arteries, were enrolled at our institute over 68 months from April 2013. They were classified into 4 groups; control with non-cardiac chest pain, MVS, diffuse spasm (DS), or focal spasm (FS) (Fig. 1A). MVS was diagnosed when negative lactate extraction ratio (coronary orifice &amp;lt; coronary sinus) was detected despite the absence of epicardial spasm during the spasm provocation test. DS was defined as epicardial spasm induced in more than 2 coronary segments in LAD, and FS as epicardial spasm in one segment. Quantitative analyses for adventitial inflammation and atherosclerotic changes were performed by calculating VV density and %area stenosis (AS) on OCT (Fig. 1B, E). Furthermore, index of microcirculatory resistance (IMR), a marker of microvascular disorder with a cut-off value of ≥25, was measured during intravenous infusion of adenosine, which was then correlated with VV densities in the MVS and DS groups. Coronary plaque with a necrotic core was classified as fibroatheroma (FA), and the number of OCT frames with internal VV (IVV) in the atheroma was counted. Results VV density was significantly higher in MVS as compared with the controls (Fig. 1B). DS was most prevalent in INOCA (Fig. 1A) with highest VV density (Fig. 1B). Patients with IMR≥25 were predominantly distributed with a gradual increase in the MVS, DS, and FS groups, but none in the controls (Fig. 1C). Importantly, there was a significant positive correlation between VV densities and IMR in the MVS and DS groups (Fig. 1D). In addition, FS had the largest plaque size and showed the highest prevalence of FA and IVV (Fig. 1E–G). Conclusions These results indicate that MVS and DS are characterized by vasomotion abnormalities associated with adventitial inflammation and microvascular disorder, while FS by vulnerable atherosclerotic phenotype, suggesting that OCT may be useful for screening high-risk populations in INOCA. Figure 1 Funding Acknowledgement Type of funding source: None

Spontaneous coronary artery dissection: novel pathophysiological insights from histological and ultrastructural tissue analysis

Abstract Introduction Spontaneous coronary artery dissection (SCAD) is a cause of acute coronary syndromes and rarely sudden cardiac death (SCD). SCAD is characterised by medial false lumen haematoma formation and periadventitial inflammatory cell infiltrate. Although SCAD has been linked to connective tissue disorders, its pathophysiology remains poorly understood and the role of inflammation unknown. Purpose We sought to establish the definitive histopathological features of SCAD and explore pathophysiological mechanisms through assessment of dermal connective tissue ultrastructure. Methods N=36 SCD cases diagnosed as SCAD on autopsy were identified in pathology archives at four international centres. Their demographic and clinical characteristics were compared with n=359 survivors recruited in a SCAD survivors cohort. Haematoxylin &amp; eosin sections were examined under light microscope. Immunohistochemistry (IHC) was employed for quantification of inflammatory cell infiltrate (CD68, CD3) and vasa vasorum density (CD31) of SCAD cases (n=20) compared to age- and sex-matched controls (n=10). Dermal extracellular matrix components (EMC) of n=32 SCAD survivors and n=16 healthy volunteers (HV) were compared using electron microscopy (EM). Results The autopsy series cases were more likely to be male (p=0.0256) and had higher incidence of left main stem (p=0.0475) and proximal left anterior descending (p&amp;lt;0.001) disease compared to SCAD survivors. N=24 (66%) of SCAD autopsy case showed no evidence of myocardial necrosis. N=17 (47%) showed mild-moderate atherosclerotic changes but no features of fibromuscular dysplasia. There were no differences in vasa vasorum density between SCAD and control cases (A). The degree of inflammatory cell infiltrate varied greatly but significantly higher than controls (B), comprising CD68+ macrophages, eosinophils and CD3+ positive T-cells. There was a statistically significant association (p=0.006) between the degree of inflammatory cell infiltrate and the length of time from onset of symptoms to death (Panel C), as well as significantly (p&amp;lt;0.001) denser inflammatory cell infiltrate adjacent to the dissection plane (D, exemplary sections E&amp;F). EM revealed no differences between SCAD and HV in dermal fibroblast size &amp; activity or elastin size &amp; damage indicators, but possible changes in subgroups with more extreme clinical phenotype or pregnancy-related SCAD (G). Conclusions To our knowledge this is the largest SCAD pathology case series so far. We show for the first time that periadvential inflammation in SCAD appears to be time-dependent and localising to the dissected coronary segment, suggesting healing response to injury rather than causal contribution. We found no evidence to suggest increased vasa vasorum density is pathophysiologically important. Connective tissue changes were only linked to a small proportion of cases. These novel findings may have important implications for the management of SCAD patients. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation, Leicester NIHR Biomedical Research Centre

A novel therapeutic approach for coronary inflammation and lymphatic vessels using non-invasive low-intensity pulsed ultrasound in a porcine model with DES-induced coronary hyperconstricting responses

Abstract Background The coronary adventitia harbors lymphatic vessels (LVs). We previously demonstrated that coronary adventitial inflammation and LV dysfunction play important roles in the pathogenesis of coronary artery spasm, including drug-eluting stent (DES)-induced coronary hyperconstricting responses, in pigs and humans. However, a direct therapeutic approach to the coronary adventitia remains to be developed. Purpose In this study, we aimed to examine whether our novel and non-invasive therapy with low-intensity pulsed ultrasound (LIPUS) ameliorates DES-induced coronary hyperconstricting responses, and if so, what mechanisms are involved. Methods An everolimus-eluting stent (EES) was implanted into the left anterior descending (LAD) coronary artery in normal male pigs. They were randomly assigned to the LIPUS or the sham therapy groups. After EES implantation, in the LIPUS group, LIPUS (32 cycles, 193 mW/cm2) was applied to the heart at 3 different levels (proximal and distal stent edges and middle portion of the stent) through X-ray fluoroscopy for 20 min at each level for every other day for 2 weeks (6 days in total) (Fig. 1A, B). The sham therapy group was treated in the same manner but without LIPUS. At 4 weeks after the procedure, we performed coronary angiography to examine coronary vasoconstricting responses to intracoronary serotonin in vivo. Finally, stented coronary vessels were harvested for immunohistochemistry of vasa vasorum (vWF), LVs (LYVE-1), vascular inflammation (CD68-positive macrophages and IL-1β expression), vascular endothelial growth factor A (VEGF-A, angiogenesis marker), VEGF-C and VEGF receptor 3 (VEGFR3, lymphangiogenesis markers). Results Coronary vasoconstricting responses to intracoronary serotonin at the DES edges in the LAD were significantly enhanced in the sham group but were significantly suppressed in the LIPUS group, while those responses were comparable at the non-DES implanted left circumflex (LCx) coronary artery between the 2 groups (Fig. 1C, D). In addition, in vivo lymph transport speed was significantly faster in the LIPUS group than in the sham group (Fig. 1E–G). In histological analysis, the number of LVs was significantly increased in the LIPUS group compared with the sham group, whereas those of CD68 and IL-1β expressions were significantly reduced in the LIPUS group compared with the sham group. In contrast, the density of vasa vasorum was comparable between the 2 groups. Mechanistically, the extents of VEGF-C and VEGFR3 expressions were increased in the LIPUS group, whereas that of VEGF-A was comparable between the 2 groups (Fig. 1G–K). Importantly, there were significant correlations among the LV-related changes and enhanced coronary vasoconstricting responses. Conclusion These results provide the first evidence that the LIPUS therapy ameliorates DES-induced coronary hyperconstricting responses in pigs in vivo through structural and functional alterations of LVs (Fig. 1L). Figure 1 Funding Acknowledgement Type of funding source: None

P1292DECREASES IN ANGIOGENIC T CELLS ARE PREDICTIVE BIOMARKERS OF VASCULAR DYSFUNCTION AND ATHEROSCLEROSIS IN CHRONIC KIDNEY DISEASE

Abstract Background and Aims The stratification of early cardiovascular (CV) risk is a major unmet need in chronic kidney disease (CKD). Since angiogenic T-cells are emerging mediators of vascular homeostasis and have been linked to CV disease (CVD), this study evaluated the frequency of circulating angiogenic T-cells in CKD patients undergoing peritoneal dialysis (CKD-5D) and their potential as predictive biomarkers of CVD. Method In 30 peritoneal dialysis patients and 16 matched healthy controls (HC), we quantified: Vascular calcification (by Kauppila Index); left carotid intima media thickness (lc-IMT by ultrasound), carotid adventitial vasa vasorum density (an early marker of atherosclerosis stage, by Superb Microvascular Ultrasound Image), pulse wave velocity (a marker of vascular stiffness and dysfunction, using the Complior Analyzer), angiogenic T cell frequency in blood (by Flow cytometry) and the traditional 10-year CVD risk (using the SCORE chart). Results As expected, CKD-5D patients exhibited higher Kauppila index (p&amp;lt;0.001), lcIMT (p=0.010) and adventitial vasa vasorum density (p=0.008) than HC. Angiogenic-T cell frequency was decreased in CKD compared to HC (1.68(1.05) vs. 3.33(1.44)%, p&amp;lt;0.001). In CKD-5D patients, angiogenic-T cell frequency was not associated with blood pressure, cholesterol levels or time on dialysis (all p&amp;gt;0.05) and did not correlate with Kauppila (r=-0.350, p=0.080) or lcIMT (r=-0.154, p=0.600), but strongly associated negatively with both pulse wave velocity (r=-0.734, p&amp;lt;0.001) and with adventitial vasa vasorum (newly formed vasa vasorum) number: r=-0.640, p=0.006; or density: r=-0.813, p&amp;lt;0.001). Angiogenic-T cell levels paralleled pulse wave velocity (B[95% CI]: -0.083[-0.155, -0.010], p=0.028; R2=0.531) and adventitial vasa vasorum -15.049[-26.705, -3.392], p=0.015; R2=0.598) and improved the prediction model over that of the SCORE chart (R2=0.360 and R2=0.336, respectively). Conclusion Angiogenic-T cell frequency was decreased in CKD-5D patients and could be considered as biomarkers of vascular dysfunction and early atherosclerosis stage.

Atherosclerotic Coronary Plaque Is Associated With Adventitial Vasa Vasorum and Local Inflammation in Adjacent Epicardial Adipose Tissue in Fresh Cadavers.

The coronary adventitia has recently attracted attention as a source of inflammation because it harbors nutrient blood vessels, termed the vasa vasorum (VV). This study assessed the link between local inflammation in adjacent epicardial adipose tissue (EAT) and coronary arterial atherosclerosis in fresh cadavers.Methods and Results:Lesion characteristics in the left anterior descending coronary artery of 10 fresh cadaveric hearts were evaluated using integrated backscatter intravascular ultrasound (IB-IVUS), and the density of the VV and levels of inflammatory molecules from the adjacent EAT were measured for each of the assessed lesions. The lesions were divided into lipid-rich, lipid-moderate, and lipid-poor groups according to percentage lipid volume assessed by IB-IVUS. Higher expression of inflammatory molecules (i.e., vascular endothelial growth factor A [VEGFA] andVEGFB) was observed in adjacent EAT of lipid-rich (n=11) than in lipid-poor (n=11) lesions (7.99±3.37 vs. 0.45±0.85 arbitrary units [AU], respectively, forVEGFA; 0.27±0.15 vs. 0.11±0.07 AU, respectively, forVEGFB; P<0.05). The density of adventitial VV was greater in lipid-rich than lipid-poor lesions (1.50±0.58% vs. 0.88±0.23%; P<0.05). Lipid-rich coronary plaques are associated with adventitial VV and local inflammation in adjacent EAT in fresh cadavers. This study suggests that local inflammation of EAT is associated with coronary plaque progression via the VV.

P864Histopathological damages in the epicardial coronary artery after ischemia and reperfusion injury in swine

Abstract Background The microscopic consequences in the myocardial capillaries after myocardial infarction (MI) have been widely addressed, but little attention has been paid to epicardial coronary arteries. Since epicardial circulation is responsible for providing blood flow to the heart, understanding the microscopical changes on the epicardial artery after MI becomes also crucial. Purpose To evaluate the dynamics of the microscopic damages in the coronary arteries post-MI in swine model of reperfused MI. Methods MI was induced in swine by transient 90-min coronary occlusion of the left anterior descending (LAD) coronary artery using angioplasty balloons. One control group and four MI groups were defined: 1) without reperfusion, and 2) 1-min, 3) 1-week, and 4) 1-month reperfusion (n=3, each). In each group, LAD (infarct-related artery) and the right coronary artery (RCA) were isolated. Taking as reference the region in which balloon was inflated, we also separated samples from two different regions: proximal and distal LAD. Histological stainings (HE, Masson's trichromic, and orcein) and immunohistochemistry against CD31 (endothelial cells), a-smooth muscle cells, and CD45 (total leukocytes) were performed. Results Abnormalities in the endothelial monolayer of the LAD artery started even before reperfusion (during ischemia). This damage dramatically increased after reperfusion, observing an almost absence of CD31+ cells in the tunica intima and some breaks in the internal elastic layer from the 1-min and 1-week reperfusion groups. No irregularities were found in the tunica media from the no reperfusion group, whereas an increased in its thickness was detected soon after reperfusion. In the 1-week reperfusion group, larger thickness, a desorganized muscular cells distribution, and oedema were found. The damage in the tunica intima and media was more pronounced in the region distal to the angioplasty balloon compared to the proximal region, whereas no changes were detected in the RCA. In the tunica adventitia, vasa vasorum density was reduced during the ischemic phase, remaining low in the 1-min and 1-week reperfusion group, while being restored after 1-month reperfusion. This dynamics was similar in both LAD regions, while no changes in the RCA were found. After coronary reperfusion, a higher leukocyte adhesion to the endothelium from the LAD artery, mainly in the region proximal to the balloon inflation, was observed. The process evolves, resulting in a massive presence of CD45+ cells not only in the tunica intima, but also in the media and the adventitia monolayer isolated from the 1-week reperfusion group. Conclusions The microscopic structure of the infarct-related coronary artery was compromised after MI. This damage started during ischemia and boosted after reperfusion, becoming more pronounced in the region distal to balloon inflation. Exploring these damages will be important for a better understanding of the pathophysiology of MI. Acknowledgement/Funding This study was funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (PIE15/00013, PI17/01836, and CIBERCV16/11

Vasa Vasorum Densities in Human Carotid Atherosclerosis Is Associated with Plaque Development and Vulnerability.

ObjectiveThe extensive vasa vasorum network functions as a conduit for the entry of inflammatory cells or factors that promote the progression of angiogenesis and plaque formation. Therefore, we investigated the correlation between the carotid vasa vasorum activities and carotid plaque vulnerability using indocyanine green video angiography (ICG-VA) during carotid endarterectomy (CEA). MethodsSixty-nine patients who underwent CEA were enrolled prospectively from September 2015 to December 2017. During CEA, a bolus of ICG was injected intravenously before and after resecting the atheroma. Additionally, we performed immunohistochemistry using CD68 (a surface marker of macrophages), CD117 (a surface marker of mast cells), and CD4 and CD8 (surface markers of T-cells) antibodies to analyze the resected plaque specimens. ResultsThe density of active vasa vasorum was observed in all patients using ICG-VA. The vasa vasorum externa (VVE) and interna (VVI) were seen in 11 (16%) and 57 patients (82.6%), respectively. Macroscopically, the VVE-type patterns were strongly associated with preoperative angiographic instability (81.8%, p=0.005) and carotid plaque vulnerability (90.9%, p=0.017). In contrast, the VVI-type patterns were weakly associated with angiographic instability (31.6%) and plaque vulnerability (49.1%). CD68-stained macrophages and CD117-stained mast cells were observed more frequently in unstable plaques than in stable plaques (p<0.0001, p=0.002, respectively). ConclusionThe early appearance of VVE, along with the presence of many microvessel channels that provided nutrients to the developing and expanding atheroma during ICG-VA, was strongly associated with unstable carotid plaques. The degree of infiltration of macrophages and mast cells is possibly related to the formation of unstable plaques.

Si-Miao-Yong-An on promoting the maturation of Vasa Vasorum and stabilizing atherosclerotic plaque in ApoE-/- mice： An experimental study

ObjectiveTo observe the intervention effect of Si-miao-Yong-An (SMYA) on atheroosclerosis (AS) vulnerable plaque, and to explore the mechanism by Vasa Vasorum (VV) maturation as a starting point. Materials and methodsSPF-class healthy male ApoE−/− mice were randomly divided into model group, SMYA group and simvastatin group, and C57BL/6 mice were used as a control group. After 8 weeks of drug intervention, the plaques of AS were observed by HE staining. The pericytes of aortic root plaques were observed by immunofiuorescence double staining (CD34, Desmin) and the density of VV. The expression of Dll4, Notch1, Hey1 and VEGF mRNA in aortic tissues was detected by real-time qPCR. ResultsSMYA significantly reduced the area of aortic plaque in ApoE−/− mice, significantly reduced plaque area and the ratio of plaque to lumen area, and reduced the intima medium thickness, it’s effect was greater than that of simvastatin; it significantly increased the density of VV in plaque. SMYA increased the expression of Dll4 and Notch1 and Hey1mRNA, and decreased the expression of VEGF mRNA, and its effect was greater than that of simvastatin. ConclusionSMYA can reduce the AS plaque area in ApoE−/− mice, promote the recruitment of VV pericytes, and stabilize AS vulnerable plaques. The mechanism may be regulate of Dll4/Notch1/ Hey1/VEGF signaling pathway. At the same time, it has a dual-direction regulation on the VV.

Spontaneous Coronary Artery Dissection: Pathophysiological Insights From Optical Coherence Tomography

ObjectivesThis study used optical coherence tomography to investigate the mechanism of false lumen (FL) formation in spontaneous coronary artery dissection (SCAD) by studying: 1) differences between fenestrated and nonfenestrated SCAD; 2) vasa vasorum density; and 3) light attenuation characteristics of the FL. BackgroundSCAD is an increasingly recognized cause of acute coronary syndromes, characterized by FL formation and compression of the true lumen (TL). The mechanisms underlying FL formation remain poorly understood. MethodsA total of 65 SCAD patients (68 vessels) who underwent acute OCT imaging as part of routine clinical care were included. Images were classified by the absence or presence of a connection (fenestration) between the TL and FL. Indexed measurements of TL stenosis, external elastic lamina (EEL) area, FL area, and light attenuation of the FL were assessed. Vasa vasorum densities of SCAD cases were compared with those in control non-SCAD myocardial infarction cases. ResultsIn nonfenestrated cases, there was significantly larger expansion of the EEL area (9.1% vs. −1.9%; p <0.05) and a larger FL area (73.6% vs. 53.2%, respectively; p <0.05) in dissected segments. No significant differences were found between vasa vasorum density in SCAD and those in control subjects. The FL contents were heterogeneous but attenuated less light than whole blood or thrombus (4.28 ± 0.55 mm−1 vs. 5.08 ± 0.56 mm−1; p < 0.05; vs. 4.96 ± 0.56 mm−1; p < 0.05). ConclusionsThese observational data suggest that the absence of a fenestration leads to increased FL pressure and compression of the TL. Although vasa vasorum may still be implicated in pathogenesis, increased vasa vasorum density could be an epiphenomenon of vascular healing.

Dysglycemia and the Density of the Coronary Vasa Vasorum.

This study was conducted to determine the relationship between dysglycemia and the coronary artery vasa vasorum density. The left anterior descending coronary artery was removed from 57 deceased individuals during autopsy, and the capillaries in the vessel wall were identified using fluorescent immunohistochemical staining. HbA1c was determined in postmortem whole blood for each individual. The density of the vasa vasorum in the intima-media and the adventitia was manually quantified and recorded by readers unaware of the individual's other characteristics. The individuals with diabetes had a lower density of the coronary vasa vasorum than those without diabetes. The higher the HbA1c, the lower the density of these vessels in the adventitia and entire vessel wall. Dysglycemia-induced damage to the vasa vasorum may promote ischemic heart disease in people with diabetes.

Influence of Morbid Obesity and Bariatric Surgery Impact on the Carotid Adventitial Vasa Vasorum Signal.

Adventitial vasa vasorum (VV) expansion to the avascular intima precedes an increase in carotid intima-media thickness. However, factors involved in the development of the atherosclerotic process and its reversibility remain unclear. We aimed to evaluate the VV signal in both morbid obesity and after bariatric surgery (BS). We conducted a case-control study to examine the VV signal in the carotid of 40 morbidly obese patients and 40 non-obese controls. The effect of BS was evaluated in 33 patients. Contrast-enhanced carotid ultrasound was used to assess the VV signal. The mean VV density was higher in obese than in non-obese subjects (0.739 ± 0.117 vs. 0.570 ± 0.111, p < 0.001). The VV signal positively correlated with BMI (p < 0.001) and waist circumference (p = 0.001) but was not related to cIMT. The stepwise multivariate regression analysis revealed that waist circumference (beta = 0.507, p < 0.001) together with fasting plasma glucose (beta = 0.229, p = 0.024) were independently associated with the VV signal (R2 = 0.382). Before BS, the median VV signal correlated with soluble intercellular adhesion molecule 1 (p = 0.022). After a 12-month follow-up, a 12.0% decrease in VV (0.731 ± 0.126 vs. 0.643 ± 0.115, p = 0.003) was observed. In the univariate analysis, the decrease in VV was associated with the baseline VV density (p < 0.001), baseline systolic blood pressure (p = 0.019) and a decrease in sICAM (p = 0.005). However, only baseline systolic pressure (beta = 0.417, p = 0.024) independently predicted the absolute change in VV signal (R2 = 0.174). Morbidly obesity is associated with increased VV density. In addition, BS appears to reduce the earlier expansion of the adventitial vasa vasorum.

Highlights From the Circulation Family of Journals.

Highlights From the Circulation Family of Journals.

A comparative study of vasa vasorum density among coronary arteries

BackgroundCoronary arteries exhibit significantly higher adventitial Vasa vasorum (VV) densities which may partly explain their higher atherosclerosis susceptibility. A variability in the atherosclerosis predispositions exists between individual coronary artery branches but few studies exist that compare their VV densities. This study aims to assess for VV density differences between individual coronary artery branches and also compare them with other similar sized peripheral arteries. MethodsCadaveric arterial specimens, 15 each, from right coronary [RCA], left anterior descending [LAD], left circumflex [LCX] radial [RA] and fibular arteries [FA] were collected, processed and stained. Images were taken using digital Motic camera enabled microscope and Motic Image plus 2.0 ML software. VV were visually identified and counted. Open source software Image J was used to measure the adventitial surface area. VV number per unit area was expressed as density. ResultsMean adventitial VV density (*10−5/μm2) was significantly higher in the RCA (2.14 SD 0.92) compared to the LAD (1.2 SD 0.72) RA (1.23 SD 0.41) and FA (0.77 SD 0.84). VV density in LAD was comparable to LCX (1.88 SD 0.83), RA and FA ConclusionLAD showed the least VV density among coronary arteries, even though most studies show this artery to have the highest atherosclerosis incidence. Interactions between high and low VV density areas within an artery rather than net VV density may be a more significant determining factor for atherosclerosis predisposition. Structural and molecular characteristics of the vessel wall, as well as that of VV, may also be contributing factors.