The Seed Coat Extract of Black Soybean Decreases Nicotine-Induced Vascular Fiber Degradation by Suppressing Matrix Metalloproteinase 2 Expression

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by weakening of vascular walls and progressive dilation of the abdominal aorta. Nicotine, the main component of tobacco, is reportedly associated with the development and rupture of AAA. It is desirable to attenuate the destructive effect of nicotine on vascular walls, using dietary food components. However, effective methods for preventing AAA progression using dietary food components remain unestablished. This study focuses on proanthocyanidins, well known for their potent antioxidant activity. We speculated that proanthocyanidins can suppress nicotine-induced weakening of vascular walls. To estimate the effect of black soybean seed coat extract (BSSCE), rich in proanthocyanidins, on nicotine-induced weakening of the aortic wall, mice were divided into four groups: the control diet and distilled water group (named C), BSSCE solution diet and distilled water group (named B), control diet and 0.5 mg/mL nicotine solution group (named CN), and BSSCE solution diet and 0.5 mg/mL nicotine solution group (named BN). Nicotine-induced degradation of elastin and collagen fibers were significantly suppressed in BN group. The positive areas for matrix metalloproteinase (MMP)-2 and oxidative stress in BN group were significantly decreased compared to those in CN group. These results suggest that proanthocyanidins-rich BSSCE can prevent the weakening of the aortic wall via inhibiting MMP-2 upregulation.

Perivascular Adipose Tissue-Derived PDGF-D Contributes to Aortic Aneurysm Formation During Obesity

Obesity increases the risk of vascular diseases, including aortic aneurysm (AA). Perivascular adipose tissue (PVAT) surrounding arteries are altered during obesity. However, the underlying mechanism of adipose tissue, especially PVAT, in the pathogenesis of AA is still unclear. Here we showed that angiotensin II (AngII) infusion increases the incidence of AA in leptin-deficient obese mice (ob/ob) and high-fat diet-induced obese mice with adventitial inflammation. Furthermore, transcriptome analysis revealed that platelet-derived growth factor-D (PDGF-D) was highly expressed in the PVAT of ob/ob mice. Therefore, we hypothesized that PDGF-D mediates adventitial inflammation, which provides a direct link between PVAT dysfunction and AA formation in AngII-infused obese mice. We found that PDGF-D promotes the proliferation, migration, and inflammatory factors expression in cultured adventitial fibroblasts. In addition, the inhibition of PDGF-D function significantly reduced the incidence of AA in AngII-infused obese mice. More importantly, adipocyte-specific PDGF-D transgenic mice are more susceptible to AA formation after AngII infusion accompanied by exaggerated adventitial inflammatory and fibrotic responses. Collectively, our findings reveal a notable role of PDGF-D in the AA formation during obesity, and modulation of this cytokine might be an exploitable treatment strategy for the condition.

A reproducible swine model of proximal descending thoracic aortic aneurysm created with intra-adventitial application of elastase

OBJECTIVE

Animal models are required to explore the mechanisms of and therapy for proximal descending thoracic aortic aneurysm (TAA). This study aimed to establish a reproducible swine model of proximal descending TAA that can further explain the occurrence and progression of proximal descending TAA.

METHODS

Eighteen Chinese Wuzhishan miniature pigs (30.32 ± 1.34 kg) were randomized into the elastase group (n = 12) and the control group (n = 6). The elastase group received intra-adventitial injections of elastase (5 mL, 20 mg/mL), and the control group received injections of physiologic saline solution. A 4-cm descending thoracic aortic segment proximal to the left subclavian artery was isolated. The distance between the left subclavian artery and the injection starting point of the descending thoracic aorta was 0.5 cm. Elastic protease was circumferentially injected intra-adventitially into the isolated segment of the aortic wall in the elastase group by a handmade bent syringe. The length of the elastic protease injection was 2 cm. An average of 12 injection points were distributed in this 2-cm aortic segment. Each injection point used about 0.4 mL of elastic protease. The distance between two injection points was about 1.5 cm. All animals underwent digital subtraction angiography preoperatively and 3 weeks after operation. Three weeks after TAA induction, aortas were harvested for biochemical and histologic measurements.

RESULTS

All animals in the elastase group developed TAAs. No aneurysms were observed in the control group. The distance between the left subclavian artery and the TAA was 8.00 ± 4.19 mm. Preoperative and postoperative aortic diameters of the elastase group were 15.42 ± 0.43 mm and 24.53 ± 1.41 mm, respectively (P < .0001). Preoperative and postoperative aortic diameters of the control group were 15.31 ± 0.33 mm and 15.57 ± 0.40 mm, respectively (P = .5211). The changes of aortic structure and composition included reduction of smooth muscle cells and degradation of elastic fibers. Levels of matrix metalloproteinases 2 and 9 were increased in TAA tissue.

CONCLUSIONS

This study established a reproducible large animal model of proximal descending TAA. This model has the same biochemical characteristics as human aneurysms in the aspects of aortic expansion, aortic middle-level degeneration, and changes in the levels of matrix metalloproteinases and provides a platform for further study.

Pro-fibrotic effect of IL-6 via aortic adventitial fibroblasts indicates IL-6 as a treatment target in Takayasu arteritis

OBJECTIVES

This study aimed to clarify potential mechanism of IL-6 involved in adventitial fibrosis via adventitial fibroblast in Takayasu arteritis (TAK).

METHODS

Immunohistochemistry and double-labelled immunofluorescence were performed on vascular tissue from patients with TAK and controls. Human aorta adventitial fibroblast (AAF) was cultured and stimulated with interleukine 6 (IL-6)/IL-6 receptor (IL-6R). Real-time PCR, western blot, enzyme-linked immunosorbent assays, chromatin immunoprecipitation (ChIP) and reporter assay were conducted in vitro experiments to determine effect of IL-6/IL-6R on AAF.

RESULTS

The expression of IL-6, IL-6R, collagen I, collagen III, fibronectin, α-smooth muscle actin (α-SMA), and transforming growth factor (TGF-β) in TAK arteries was significantly higher than that in the normal arteries. Co-localisation of α-SMA and IL-6 and a positive correlation between their expression were observed in local lesions. In vitro experiments, collagen I, collagen III, fibronectin, α-SMA, and TGF-β expression increased significantly after stimulation and this fibrogenesis of AAFs was induced in TGF-β-dependent and -independent manners. Additionally, phosphorylation of JAK2, STAT3 and Akt was significantly enhanced both in IL-6/IL-6R-treated AAFs in vitro and in TAK adventitial α-SMA positive cells. When AAFs were pretreated with inhibitors against JAK2, STAT3, and Akt, fibrosis was significantly reduced. Furthermore, IL-6/IL-6R promoted mRNA expression of IL-6 and MCP-1 in AAFs. Finally, according to ChIP and reporter assay results, STAT3 was the main transcriptional factor in the fibrosis of AAFs induced by IL-6/IL-6R.

CONCLUSIONS

IL-6/IL-6R induces fibrogenesis of AAFs via the JAK2/STAT3 and JAK2/Akt pathways, which provides theoretical evidence for IL-6 as a treatment target in TAK.

Controlling the Release of Small, Bioactive Proteins via Dual Mechanisms with Therapeutic Potential

Injectable delivery systems that respond to biologically relevant stimuli present an attractive strategy for tailorable drug release. Here, the design and synthesis of unique polymers are reported for the creation of hydrogels that are formed in situ and degrade in response to clinically relevant endogenous and exogenous stimuli, specifically reducing microenvironments and externally applied light. Hydrogels are formed with polyethylene glycol and heparin-based polymers using a Michael-type addition reaction. The resulting hydrogels are investigated for the local controlled release of low molecular weight proteins (e.g., growth factors and cytokines), which are of interest for regulating various cellular functions and fates in vivo yet remain difficult to deliver. Incorporation of reduction-sensitive linkages and light-degradable linkages affords significant changes in the release profiles of fibroblast growth factor-2 (FGF-2) in the presence of the reducing agent glutathione or light, respectively. The bioactivity of the released FGF-2 is comparable to pristine FGF-2, indicating the ability of these hydrogels to retain the bioactivity of cargo molecules during encapsulation and release. Further, in vivo studies demonstrate degradation-mediated release of FGF-2. Overall, our studies demonstrate the potential of these unique stimuli-responsive chemistries for controlling the local release of low molecular weight proteins in response to clinically relevant stimuli.

[Angiotensin II induces expression of inflammatory mediators in vascular adventitial fibroblasts]

Vascular adventitial fibroblasts (AF) may play an important role in vascular inflammation. This study was aimed to investigate the expression pattern of inflammatory mediators in AF induced by angiotensin II (AngII) and to explore the effects of AF-derived inflammatory mediators on the adhesion and migration of macrophages both in vitro and in vivo. We used real-time RT-PCR to detect the mRNA expression of inflammatory mediators in cultured AF. The results showed that AngII (1 × 10(-7) mol/L) up-regulated mRNA expression of 4 inflammatory mediators, including P-selectin, ICAM-1, IL-6 and MCP-1, in cultured AF. Western blot analysis or ELISA revealed that AngII up-regulated P-selectin and ICAM-1 protein expression and IL-6 secretion in cultured AF, but did not alter MCP-1 secretion. We further detected the effects of AF-derived inflammatory mediators on the adhesion and chemotaxis of RAW264.7, a macrophage cell line. We found that AF stimulated with AngII could enhance the adhesion of RAW264.7 and the conditioned medium from AngII-stimulated AF could enhance the migration of RAW264.7. Immunofluorescence study showed an enhanced accumulation of CD68 positive cells and the up-regulation of P-selectin, ICAM-1, IL-6 and MCP-1 in aortic adventitia of AngII-infused (200 ng/kg per min for 2 weeks) rats. We concluded that AF may contribute to vascular inflammation via expression of certain inflammatory mediators and the subsequent adhesion and chemotaxis of macrophages.

Analysis of Microtubule-Associated-Proteins during IBA-Mediated Adventitious Root Induction Reveals KATANIN Dependent and Independent Alterations of Expression Patterns

Adventitious roots (AR) are post embryonic lateral organs that differentiate from non-root tissues. The understanding of the molecular mechanism which underlies their differentiation is important because of their central role in vegetative plant propagation. Here it was studied how the expression of different microtubule (MT)-associated proteins (MAPs) is affected during AR induction, and whether expression differences are dependent on MT organization itself. To examine AR formation when MTs are disturbed we used two mutants in the MT severing protein KATANIN. It was found that rate and number of AR primordium formed following IBA induction for three days was reduced in bot1-1 and bot1-7 plants. The reduced capacity to form ARs in bot1-1 was associated with altered expression of MAP-encoding genes along AR induction. While the expression of MAP65-4, MAP65-3, AURORA1, AURORA2 and TANGLED, increased in wild-type but not in bot1-1 plants, the expression of MAP65-8 and MDP25 decreased in wild type plants but not in the bot1-1 plant after two days of IBA-treatment. The expression of MOR1 was increased two days after AR induction in wild type and bot1-1 plants. To examine its expression specifically in AR primordium, MOR1 upstream regulatory sequence was isolated and cloned to regulate GFP. Expression of GFP was induced in the primary root tips and lateral roots, in the pericycle of the hypocotyls and in all stages of AR primordium formation. It is concluded that the expression of MAPs is regulated along AR induction and that reduction in KATANIN expression inhibits AR formation and indirectly influences the specific expression of some MAPs.

[Intervention Mechanism of Extracts from Radix Ginseng, Radix Notoginseng and Rhizoma Chuanxiong on Adventitia of Senescent Rats]

OBJECTIVE

To observe the reconstruction features of adventitia in senescent rats, and to explore the intervention mechanism of Chinese herbs (CH, extracts from Radix Ginseng, Radix Notoginseng, and Rhizoma Chuanxiong).

METHODS

Totally 85 20-month senescent rats were randomly divided into 5 groups according to body weight, i.e., the aging model group, the high dose CH group, the middle dose CH group, the low dose CH group, the Losartan group, 17 in each group. Another 14 2-month old Wistar rats were selected as a young group. Extracts of CH at the daily dose of 1493. 4, 746. 7, and 373. 4 mg/kg were administered to rats in the 3 CH groups respectively by gastrogavage. Losartan suspension at the daily dose of 10 mg/kg was administered to rats in the Losartan group by gastrogavage. Equal volume of distilled water was administered to rats in the aging model group and the young group. All medication was performed once daily. After 15-week intervention, morphological changes of thoracic aorta were observed by HE staining. The types, distribution, and contents of vessel wall collagens were determined using picric acid picrosirius red staining. The plasma renin activity (PRA) , the concentration of rennin angiotensin II (Ang II), and the content of Ang II in adventitia were detected by radioimmunoassay. The content of hydroxyproline ( Hyp) was detected by biochemical analysis. mRNA contents and protein expressions of angiotensin II receptor 1 (AT1R) and angiotensin II receptor 2 (AT2R) were detected by real-time PCR (RT-PCR) and Western blot.

RESULTS

Compared with the young group, thickened adventitia, increased adventitia thickness/caliber, accumulated collagen fiber, increased area of type I collagen, decreased area of type III collagen, decreased type III/I collagen area ratio (P <0. 05), decreased plasma PRA and Ang II (P < 0.01, P < 0.05), increased contents of Ang II and Hyp in adventitia, down-regulated mRNA and protein expressions of AT1R, and up-regulated mRNA and protein expression of AT2R could be seen in the aging model group (P < 0.05). Compared with the aging model group, morphological changes could be improved in the 3 CH groups. Adventitia thickness/caliber was reduced in middle and high dose CH groups, as well as the Losartan group. The area of type I collagen was reduced and the area of type III collagen was enlarged, type III/I collagen area ratio obviously increased, contents of adventitia Hyp was obviously lowered in the high dose CH groups and the Losartan group (P < 0.05, P < 0.01). Ang II levels in adventitia decreased in middle and high dose CH groups and the Losartan group (P < 0.05, P < 0.01). There was no statistical difference in PAR among all groups (P > 0.05). Compared with the aging model group, mRNA expression of AT1R all increased in each treatment group (P < 0.01); mRNA expression of AT2R also increased in middle and high dose CH groups (P < 0.05). Protein expression of AT1R increased in the high dose CH group and the Losartan group (P < 0.01, P < 0.05); protein expression of AT2R also increased in middle and high dose CH groups (P < 0.05).

CONCLUSIONS

Adventitia remodeling occurred in aged rats, manifested as thickened adventitia and accumulated collagens, disordered ratios of collagen I and III. Its mechanism might be possibly associated with aactivation of renin-angiotensin system (RAS). Extracts from Radix Ginseng, Radix Notoginseng, and Rhizoma Chuanxiong could improve adventitial remodeling possibly by interfering multi-targets, such as Ang II and AT1R, thereby delaying vascular aging.

Aortic and carotid arterial stiffness and epigenetic regulator gene expression changes precede blood pressure rise in stroke-prone Dahl salt-sensitive hypertensive rats

Multiple clinical studies show that arterial stiffness, measured as pulse wave velocity (PWV), precedes hypertension and is an independent predictor of hypertension end organ diseases including stroke, cardiovascular disease and chronic kidney disease. Risk factor studies for arterial stiffness implicate age, hypertension and sodium. However, causal mechanisms linking risk factor to arterial stiffness remain to be elucidated. Here, we studied the causal relationship of arterial stiffness and hypertension in the Na-induced, stroke-prone Dahl salt-sensitive (S) hypertensive rat model, and analyzed putative molecular mechanisms. Stroke-prone and non-stroke-prone male and female rats were studied at 3- and 6-weeks of age for arterial stiffness (PWV, strain), blood pressure, vessel wall histology, and gene expression changes. Studies showed that increased left carotid and aortic arterial stiffness preceded hypertension, pulse pressure widening, and structural wall changes at the 6-week time-point. Instead, differential gene induction was detected implicating molecular-functional changes in extracellular matrix (ECM) structural constituents, modifiers, cell adhesion, and matricellular proteins, as well as in endothelial function, apoptosis balance, and epigenetic regulators. Immunostaining testing histone modifiers Ep300, HDAC3, and PRMT5 levels confirmed carotid artery-upregulation in all three layers: endothelial, smooth muscle and adventitial cells. Our study recapitulates observations in humans that given salt-sensitivity, increased Na-intake induced arterial stiffness before hypertension, increased pulse pressure, and structural vessel wall changes. Differential gene expression changes associated with arterial stiffness suggest a molecular mechanism linking sodium to full-vessel wall response affecting gene-networks involved in vascular ECM structure-function, apoptosis balance, and epigenetic regulation.

Effects of hydroxysafflor yellow A on proliferation and collagen synthesis of rat vascular adventitial fibroblasts induced by angiotensin II

1) examine the effects of hydroxysafflor yellow A (HSYA) on the proliferation, collagen and cytokine synthesis of vascular adventitial fibroblasts as induced by angiotensin II (Ang II) in normal Sprague-Dawley (SD) rats in vitro, and 2) to assess the effects of HSYA on morphological changes and collagen accumulation of vascular adventitia in spontaneously hypertensive rats (SHR) in vivo. In vitro experiment, vascular adventitial fibroblasts from SD rats were isolated, cultured, and divided into control groups, model groups and HSYA groups. Cell morphology of adventitial fibroblasts was assessed using laser confocal microscopy, while cell proliferation with the MTT assay, and collagen synthesis was determined using hydroxyproline chromatometry. Immunocytochemistry and reverse transcription PCR were used for detecting the expression of TGF-β1, MMP-1, α-SMA and NF-κB in adventitial fibroblasts. In vivo experiment, vascular adventitia proliferation and collagen synthesis were analyzed using hematoxylin-eosin and Sirius staining. Our results showed that: 1) in vitro experiment of SD rats, HSYA inhibited proliferative activity and collagen synthesis of adventitial fibroblasts as induced by Ang II, and the inhibitory effects of HSYA on the increased expression of MMP-1, TGF-β1, α-SMA and NF-κB p65 as induced by Ang II were assessed, and 2) in vivo experiment of SHR, histological analysis displayed fewer pathological changes of vascular adventitia in HSYA treatment groups as compared with no HSYA treatment groups, and MMP-1, TGF-β1, α-SMA and NF-κB p65 expression significantly reduced after HSYA treatment (P < 0.05). Our results revealed that HSYA treatment significantly decreased the amount of cytokines and collagen synthesis in vascular adventitia components. This study provides experimental evidence demonstrating that HSYA has the capacity to decrease vascular adventitia proliferation and hyperplasia during vascular remodeling.

Effect of CTRP3 on activation of adventitial fibroblasts induced by TGF-β1 from rat aorta in vitro

CTRP3, discovered as novel adipokines, is a member of the C1q tumor necrosis factor (TNF) related protein (CTRP) super-family. CTRP3 is found to function as adipokines that display diverse biological activities in metabolic and cardiovascular diseases. Recent study demonstrated that CTRP3 was protective against pathological cardiac remodeling in mice. Nevertheless, the effect of CTRP3 on vascular remodeling remains undefined. Our present study aimed to explore the effects of adipokine CTRP3 on the activation of adventitial fibroblasts (AFs) induced by TGF-β1. Immunofluorescent staining, real-time PCR and Western blot were conducted to evaluate the expression of α-smooth muscle-actin (α-SMA) and collagen I. The expression of CTGF was evaluated by enzymelinked immunosorbent assay (ELISA), while the proliferation and migration of adventitial fibroblasts were detected by using cell counting kit-8 (CCK-8) assay and Transwell technique, respectively. Functional analysis showed that CTRP3 inhibited TGF-β1 inducing AFs phenotypic conversion, collagen synthesis, proliferation and migration. The secretion of CTGF was also inhibited by CTRP3. Our findings suggest that CTRP3 may be beneficial to the prevention of cardiovascular diseases and provide a promising therapeutic strategy to attenuate vascular remodeling.

SIRT1 inhibits TNF-α-induced apoptosis of vascular adventitial fibroblasts partly through the deacetylation of FoxO1

Sirtuin 1 (SIRT1), a NAD(+)-dependent class III histone deacetylase, participates in regulating cellular apoptosis, senescence and metabolism by deacetylating histones and multiple transcription factors. In this study, we aimed to determine the effect of SIRT1 on the apoptosis of vascular adventitial fibroblasts (VAFs) and related signaling pathways. SIRT1 was found in the nucleus of VAFs and translocated into the cytoplasm in response to tumor necrosis factor-α (TNF-α). Moreover, SIRT1 protein expression was reduced in VAFs stimulated with TNF-α. In addition, TNF-α increased the apoptosis of VAFs. Activation of SIRT1 by resveratrol (RSV) or overexpression of SIRT1 attenuated TNF-α-induced VAF apoptosis by decreasing the percentage of apoptotic cells and cleaved caspase-3 protein expression and increasing the Bcl-2/Bax ratio. In contrast, inhibition of SIRT1 by sirtinol/nicotinamide or knockdown of SIRT1 enhanced apoptosis of VAFs. On the other hand, knockdown of FoxO1 reduced TNF-α-induced VAF apoptosis. SIRT1 interacted with FoxO1 in VAFs by the co-immunoprecipitation assay. Further study showed that RSV or SIRT1 overexpression decreased acetylated-FoxO1 (Ac-FoxO1) protein expression in VAFs stimulated with TNF-α. Knockdown of SIRT1 resulted in an increase in Ac-FoxO1 protein expression. Taken together, these findings indicate that SIRT1 inhibits the apoptosis of VAFs, whereas FoxO1 promotes VAF apoptosis. Furthermore, the inhibitory effect of SIRT1 on VAF apoptosis is partly mediated by the deacetylation of FoxO1.

Hemocoagulase atrox reduces vascular modeling in rabbit carotid artery adventitia

OBJECTIVE

This study aimed to compare the effects of hemocoagulase atrox and cauterization hemostasis on intimal hyperplasia and explore the effect of hemocoagulase atrox on vascular modeling in rabbit carotid artery adventitia.

METHODS

A total of 27 rabbits were randomly divided into 3 groups (0d, 14d, 28d). They were anaesthetized using an intramuscular injection of phenobarbital sodium (1 ml/kg). The left and right common carotid arteries were exposed and capillary hemorrhaged after blunt dissection of the adventitia layers of common carotid arteries. Nine rabbits in each group were again randomly divided into 3 groups, in which animals were respectively treated with hemocoagulase (2 U/ml), cauterization (power = 40 w) and saline (as control). Groups of animals were euthanized at 0, 14 and 28 days after surgery. The samples were equally divided in the middle of the adventitia removal section to obtain equal parts for histologic, immunohistochemical and molecular biologic analysis. The vascular repair after adventitial stripping was observed by HE staining, Masson staining and transmission electron microscopy. The expression of carotid MCP-1, PCNA, TGF-β1, α-SMA and VEGF were measured at different time points by RT-PCR and immunohistochemical staining.

RESULTS

HE staining and Masson staining showed that hemocoagulase atrox had a significantly stronger effect on reducing intimal hyperplasia than the cauterization after 14 and 28 days. The results of RT-PCR showed that the expression of MCP-1, TGF-β1, α-SMA and VEGF in hemocoagulase atrox-treated animals were lower than that of cauterization-treated animals.

CONCLUSION

Our results suggested that hemocoagulase atrox as a topical hemostatic is safety and efficiently and it can accelerate adventitia restoration and decrease intimal proliferation.

Sirolimus stimulates vascular stem/progenitor cell migration and differentiation into smooth muscle cells via epidermal growth factor receptor/extracellular signal-regulated kinase/β-catenin signaling pathway

OBJECTIVE

Sirolimus-eluting stent therapy has achieved considerable success in overcoming coronary artery restenosis. However, there remain a large number of patients presenting with restenosis after the treatment, and the source of its persistence remains unclarified. Although recent evidence supports the contribution of vascular stem/progenitor cells in restenosis formation, their functional and molecular responses to sirolimus are largely unknown.

APPROACH AND RESULTS

Using an established technique, vascular progenitor cells were isolated from adventitial tissues of mouse vessel grafts and purified with microbeads specific for stem cell antigen-1. We provide evidence that vascular progenitor cells treated with sirolimus resulted in an induction of their migration in both transwell and wound healing models, clearly mediated by CXCR4 activation. We confirmed the sirolimus-mediated increase of migration from the adventitial into the intima side using an ex vivo decellularized vessel scaffold, where they form neointima-like lesions that expressed high levels of smooth muscle cell (SMC) markers (SM-22α and calponin). Subsequent in vitro studies confirmed that sirolimus can induce SMC but not endothelial cell differentiation of progenitor cells. Mechanistically, we showed that sirolimus-induced progenitor-SMC differentiation was mediated via epidermal growth factor receptor and extracellular signal-regulated kinase 1/2 activation that lead to β-catenin nuclear translocation. The ablation of epidermal growth factor receptor, extracellular signal-regulated kinase 1/2, or β-catenin attenuated sirolimus-induced SM-22α promoter activation and SMC differentiation.

CONCLUSIONS

These findings provide direct evidence of sirolimus-induced progenitor cell migration and differentiation into SMC via CXCR4 and epidermal growth factor receptor/extracellular signal-regulated kinase/β-catenin signal pathways, thus implicating a novel mechanism of restenosis formation after sirolimus-eluting stent treatment.

Qindan capsule changes adventitial collagen synthesis in spontaneously hypertensive rats

OBJECTIVE

To investigate the effect of Qindan capsule (QC) on collagen synthesis and the mechanism underlying the process in spontaneously hypertensive rats (SHRs).

METHODS

Twentyfour SHRs were divided into three groups: the hypertension model group, the QC treatment group, and the losartan treatment group. Eight Wistar Kyoto (WKY) rats were used as the normal control group. The systolic blood pressure (SBP) of the rats was monitored, and the thoracic aorta adventitia of the rats was segregated. The expressions of transforming growth factor 1 (TGF-β1), Smad3, and collagens I and were measured by histological staining and reverse transcription polymerase chain reaction.

RESULTS

The SBP was significantly higher in the model group than in the normal control group (P<0.01). However, a significant SBP-lowering effect was observed in QC or losartan treatment groups (P<0.05 or P<0.01) after 3 weeks of treatment. QC-treated rats showed a decrease of approximately 40 mm Hg, and the losartan-treated rats showed a decrease of approximately 50 mm Hg at the end of treatment compared with the beginning of treatment. The protein and gene levels of TGF-β1, Smad3, and collagens I and in the model group were significantly increased compared with those in the normal control group (P<0.01). However, the levels were significantly decreased in the QC or losartan treatment group compared with the model group (P<0.05 or P<0.01). However, there was no significant difference between the QC and losartan treatment groups (P<0.05).

CONCLUSIONS

QC could exert its antihypertensive effect through down-regulating TGF-β1-stimulated collagen expressions. The TGF-β1/Smad3 signaling pathway may be involved in this process.

Mechanisms of vasodilatatory effect of perivascular tissue of human internal thoracic artery

It has beed showed that perivascular adipose tissue (PVAT) of human internal thoracic artery (ITA) releases adventitia/adipocyte-derived relaxing factor (ADRF). The precise mechanism of vasodilatatory effect of ADRF is still unknown. It was suggested that various potassium channels may be involved in the action of ADRF. The aim of this study was to assess the involvment of potassium channels in the vasorelaxing properties of ADRF in human internal thoracic artery. Human ITA rings were studied in vitro. First the ability of perivascular tissue of human ITA to release ADRF to the bath was checked. In subsequent experiments two fragments of skeletonised ITA were used to assess the involvement of various potassium channels in vasorelaxing action of PVAT. Segment of ITA, precontracted with serotonin (10(-5.5)M), was relaxed by adding PVAT to tissue bath, first without and then in the presence of appropriate potassium channel blocker. Second segment served as a control (no addition of PVAT). The magnitude of relaxation was measured and compared between preparations. This protocol was used to analyze the influence of iberiotoxin (100 nM), apamin (1 uM), 4-aminopyridine (1 mM, 5 mM), BaCl₂ (100 uM) and glibenclamide (10 uM). The addition of PVAT to precontracted skeletonized ITA caused significant vasorelaxation (54.6±8.03 mN versus 33.7±6.58 mN p=0.03). Similar effect was seen when 5 ml of aliquot from separate incubation of PVAT was added (36.3±5.45 mN versus 20.7±3.02 mN; p<0.001). PVAT dependent relaxation was blocked in the presence of Ca⁺² dependent potassium channel blocker iberiotoxin (47.4±16.67 mN versus 43.3±14.54 mN; p=0.36) and 4-aminopyridine (5 mM) (59.3±3.54 mN versus 51.6±4.77 mN; p=0.12). We conclude that perivascular adipose tissue of human ITA releases relaxing factor that seems to act with the involvement of Ca⁺² dependent potassium channels.

[Effect of adventitia cells on occurrence and development of atherosclerosis]

The effect of adventitia on the occurrence and development of atherosclerosis (As) is getting more attentions. Fibroblasts, mast cells, dendritic cells, vasa vasorums, vascular-associated lymphoid tissues, and vascular peripheral nerves are related to the occurrence and development of As. This essay summarizes studies on the changes in adventitia in As process and its effect on the occurrence and development of As, as well as the latest progress.