Overexpression of matrix metalloproteinase-9 is correlated with carotid intraplaque hemorrhage in a swine model

Metformin Directly Binds to MMP-9 to Improve Plaque Stability

Vulnerable atherosclerotic plaque rupture is the principal mechanism that accounts for myocardial infarction and stroke. High matrix metalloproteinase-9 (MMP-9) expression and activity have been proven to lead to plaque instability. Metformin, a first-line treatment for type 2 diabetes, is beneficial to plaque vulnerability. However, the mechanism underlying its anti-atherogenic effect remains unclear. Molecular docking and surface plasmon resonance experiments showed that metformin directly interacts with MMP-9, and incubated MMP-9 overexpressing HEK293A cells with metformin (1 μmol·L^-1) significantly attenuates MMP-9's activity using zymography and MMP activity assays. Moreover, metformin treatment drives MMP-9 degradation. Next, we constructed a carotid artery atherosclerotic plaque model and administered consecutive 14-day metformin (200 mg·kg^-1·d^-1) treatment by intragastric gavage. Immunofluorescence staining of the right carotid common artery and serum MMP activity assay results showed that metformin treatment decreased local plaque MMP-9 protein level and circulating MMP-9 activity, respectively. Histochemical staining revealed that after metformin treatment, the collagen content in plaque was significantly preserved, and the plaque vulnerability index decreased. These findings suggested that metformin improved atherosclerotic plaque stability by directly binding to MMP-9 and driving its degradation.

Identification of core genes associated with the anti-atherosclerotic effects of Salvianolic acid B and immune cell infiltration characteristics using bioinformatics analysis

Background

Atherosclerosis (AS) is the greatest contributor to pathogenesis of atherosclerotic cardiovascular disease (ASCVD), which is associated with increased mortality and reduced quality of life. Early intervention to mitigate AS is key to prevention of ASCVD. Salvianolic acid B (Sal B) is mainly extracted from root and rhizome of Salvia Miltiorrhiza Bunge, and exerts anti-atherosclerotic effect. The purpose of this study was to screen for anti-AS targets of Sal B and to characterize immune cell infiltration in AS.

Methods

We identified targets of Sal B using SEA (http://sea.bkslab.org/) and SIB (https://www.sib.swiss/) databases. GSE28829 and GSE43292 datasets were obtained from Gene Expression Omnibus database. We identified differentially expressed genes (DEGs) and performed enrichment analysis. Weighted gene co-expression network analysis (WGCNA) was used to determine the most relevant module associated with atherosclerotic plaque stability. Intersecting candidate genes were evaluated by generating receiver operating characteristic (ROC) curves and molecular docking. Then, immune cell types were identified using CIBERSOFT and single-sample gene set enrichment analysis (ssGSEA), the relationship between candidate genes and immune cell infiltration was evaluated. Finally, a network-based approach to explore the candidate genes relationship with microRNAs (miRNAs) and Transcription factors (TFs).

Results

MMP9 and MMP12 were been selected as candidate genes from 64 Sal B-related genes, 81 DEGs and turquoise module with 220 genes. ROC curve results showed that MMP9 (AUC = 0.815, P<0.001) and MMP12 (AUC = 0.763, P<0.001) were positively associated with advanced atherosclerotic plaques. The results of immune infiltration showed that B cells naive, B cells memory, Plasma cells, T cells CD8, T cells CD4 memory resting, T cells CD4 memory activated, T cells regulatory (Tregs), T cells gamma delta, NK cells activated, Monocytes, and Macrophages M0 may be involved in development of AS, and the candidate genes MMP9 and MMP12 were associated with these immune cells to different degrees. What’ s more, miR-34a-5p and FOXC1, JUN maybe the most important miRNA and TFs.

Conclusion

The anti-AS effects of Sal B may be related to MMP9 and MMP12 and associated with immune cell infiltration, which is expected to be used in the early intervention of AS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03670-6.

The Role of Matrix Metalloproteinase-9 in Atherosclerotic Plaque Instability

Matrix metalloproteinase-9 (MMP-9) belongs to the MMP family and has been widely investigated. Excessive MMP-9 expression can enhance extracellular matrix degradation and promote plaque instability. Studies have demonstrated that MMP-9 levels are higher in vulnerable plaques than in stable plaques. Additionally, several human studies have demonstrated that MMP-9 may be a predictor of atherosclerotic plaque instability and a risk factor for future adverse cardiovascular and cerebrovascular events. MMP-9 deficiency or blocking MMP-9 expression can inhibit plaque inflammation and prevent atherosclerotic plaque instability. All of these results suggest that MMP-9 may be a useful predictive biomarker for vulnerable atherosclerotic plaques, as well as a therapeutic target for preventing atherosclerotic plaque instability. In this review, we describe the structure, function, and regulation of MMP-9. We also discuss the role of MMP-9 in predicting and preventing atherosclerotic plaque instability.

Thromboembolic Events with Enterprise Versus Pipeline: Porcine In Vivo Experiment

BACKGROUND

Thromboembolic complications are serious adverse events associated with stenting of intracranial aneurysms. For the development of novel devices, currently no practical model exists to evaluate distal embolic events. The purpose of the current study was 2-fold: 1) assess the feasibility of a porcine carotid bifurcation model for in vivo testing of stent thrombogenicity and 2) compare the thrombogenicity of the Enterprise vascular reconstruction device versus the Pipeline embolization device (PED).

METHODS

Six Yorkshire pigs underwent implantation of size-matched devices across the carotid bifurcation. Each animal received 1 Enterprise and 1 PED contralaterally. Baseline and 2-week follow-up angiography were performed. Images were analyzed including detailed measurements of the rete mirabile, a small-vessel conglomerate supplied by branches of the common carotid artery.

RESULTS

In the absence of thromboembolic events at 2 weeks (n = 8), the perfused rete area measured 134.4 ± 6.9 mm². In the presence of thromboembolic events (n = 4), the perfused rete was reduced to an area covering 37.1 ± 8.6 mm² (P < 0.01). There was no difference in thrombogenicity between Enterprise and PED with a thromboembolic event rate of 33.3% for both devices (P > 0.99).

CONCLUSION

The swine carotid stent model allows in vivo analysis of device-related thrombogenicity and distal embolic event rates. Size reduction of the perfused rete mirabile indicates the presence of thromboembolic events. Both Enterprise and PED were associated with similar thrombogenicity in this experiment.

Endogenous Interleukin-1β Is Implicated in Intraplaque Hemorrhage in Apolipoprotein E Gene Null Mice

BACKGROUND

Intraplaque hemorrhage (IPH) has been implicated in plaque instability and rupture in atherosclerotic lesions, although the mechanisms by which IPH progresses remain largely unknown. In this study, apolipoprotein E-deficient mice with carotid artery ligation and cuff placement around the artery were used, and pro-inflammatory cytokines that are implicated in IPH were analyzed.Methods and Results:The expression of interleukin-1β (IL-1β) increased significantly following cuff placement compared with mice with carotid artery ligation alone. IPH occurred in the cuff-placed carotid artery following treatment with the negative control (NC) small interfering RNA (siRNA). However, the occurrence was significantly reduced in the cuff-placed carotid artery following treatment with an IL-1β siRNA. Neovessel formation was significantly reduced in the carotid artery treated with the NC siRNA compared with that treated with IL-1β siRNA. IL-1β significantly inhibited the tube formation and wound healing capacities of vascular endothelial cells in vitro. Furthermore, immunostaining of matrix metalloproteinase-9 (MMP-9) significantly increased in the carotid artery treated with the NC siRNA compared with that treated with IL-1β siRNA.

CONCLUSIONS

These results suggest that endogenous IL-1β is implicated in the progression of IPH via the inhibition of physiological angiogenesis in the atherosclerotic plaque, leading to the formation of leaky neovessels. Furthermore, the stimulation of MMP-9 expression may also contribute to the formation of leaky neovessels.

Animal models for plaque rupture: a biomechanical assessment

Rupture of atherosclerotic plaques is the main cause of acute cardiovascular events. Animal models of plaque rupture are rare but essential for testing new imaging modalities to enable diagnosis of the patient at risk. Moreover, they enable the design of new treatment strategies to prevent plaque rupture. Several animal models for the study of atherosclerosis are available. Plaque rupture in these models only occurs following severe surgical or pharmaceutical intervention. In the process of plaque rupture, composition, biology and mechanics each play a role, but the latter has been disregarded in many animal studies. The biomechanical environment for atherosclerotic plaques is comprised of two parts, the pressure-induced stress distribution, mainly - but not exclusively – influenced by plaque composition, and the strength distribution throughout the plaque, largely determined by the inflammatory state. This environment differs considerably between humans and most animals, resulting in suboptimal conditions for plaque rupture. In this review we describe the role of the biomechanical environment in plaque rupture and assess this environment in animal models that present with plaque rupture.

FGFR3 silencing by siRNA inhibits invasion of A549 cells

The present study identified that fibroblast growth factor receptor 3 (FGFR3) was significantly upregulated in bone metastasis of lung adenocarcinoma. RNA interference (RNAi) is a powerful approach for treating a wide range of human diseases, including cancer, through downregulating the expression of selected genes. In the present study, the invasiveness of A549 cells cultured in vitro was altered by small interfering (si)RNA targeting FGFR3, and the regulatory effect of silencing FGFR3 on the expression levels of E-cadherin and matrix metalloproteinase (MMP)9 was investigated. Human lung adenocarcinoma A549 cells were transfected with synthetic specific siRNAs targeting a fragment of the FGFR3 gene (namely, siRNA-855, siRNA-1447 and siRNA-2076) or with negative control (NC) siRNA. Cells were divided into five groups (A, siRNA-855 group; B, siRNA-1447 group; C, siRNA-2076 group; D, NC-siRNA group; and E, blank control group). The effect of the above siRNAs targeting FGFR3 on the invasion capacity of A549 cells was detected by Transwell assay. siRNAs against FGFR3 were transfected into A549 cells with by Lipofectamine^® 2000, and the expression levels of FGFR3, E-cadherin and MMP9 were measured by reverse transcription-quantitative polymerase chain reaction and western blot assay. The experimental findings indicated that the expression levels of FGFR3 and MMP9 were significantly reduced in the siRNA-FGFR3-transfected groups (A-C groups), compared with those in the D and E groups (P<0.01). In addition, the expression levels of E-cadherin were markedly elevated in the A-C groups, compared with those in the D and E groups (P<0.01). There was no significant difference in E-cadherin expression between the A-C groups, or between the D and E groups (P>0.05). These results indicated that siRNA-FGFR3 was able to decrease the invasiveness of A549 cells, inhibit the expression of MMP9 and increase the expression of E-cadherin by downregulating the expression of FGFR3. Taken together, the results of the present study indicated that the upregulation of E-cadherin expression and the downregulation of MMP9 expression are able to inhibit the migration of A549 cells, and siRNA silencing FGFR3 acts as a tumor suppressor in these cells.

Hydrocortisone supresses inflammatory activity of metalloproteinase-8 in carotid plaque

Objective

Matrix metalloproteinases are inflammatory biomarkers involved in carotid plaque instability. Our objective was to analyze the inflammatory activity of plasma and carotid plaque MMP-8 and MMP-9 after intravenous administration of hydrocortisone.

Methods

The study included 22 patients with stenosis ≥ 70% in the carotid artery (11 symptomatic and 11 asymptomatic) who underwent carotid endarterectomy. The patients were divided into two groups: Control Group - hydrocortisone was not administered, and Group 1 - 500 mg intravenous hydrocortisone was administered during anesthetic induction. Plasma levels of MMP-8 and MMP-9 were measured preoperatively (24 hours before carotid endarterectomy) and at 1 hour, 6 hours and 24 hours after carotid endarterectomy. In carotid plaque, tissue levels of MMP-8 and MMP-9 were measured.

Results

Group 1 showed increased serum levels of MMP- 8 (994.28 pg/ml and 408.54 pg/ml, respectively; P=0.045) and MMP-9 (106,656.34 and 42,807.69 respectively; P=0.014) at 1 hour after carotid endarterectomy compared to the control group. Symptomatic patients in Group 1 exhibited lower tissue concentration of MMP-8 in comparison to the control group (143.89 pg/ml and 1317.36 respectively; P=0.003). There was a correlation between preoperative MMP-9 levels and tissue concentrations of MMP-8 (P=0.042) and MMP-9 (P=0.019) between symptomatic patients in the control group.

Conclusion

Hydrocortisone reduces the concentration of MMP- 8 in carotid plaque, especially in symptomatic patients. There was an association between systemic and tissue inflammation.

Animal models of surgically manipulated flow velocities to study shear stress-induced atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial tree that develops at predisposed sites, coinciding with locations that are exposed to low or oscillating shear stress. Manipulating flow velocity, and concomitantly shear stress, has proven adequate to promote endothelial activation and subsequent plaque formation in animals. In this article, we will give an overview of the animal models that have been designed to study the causal relationship between shear stress and atherosclerosis by surgically manipulating blood flow velocity profiles. These surgically manipulated models include arteriovenous fistulas, vascular grafts, arterial ligation, and perivascular devices. We review these models of manipulated blood flow velocity from an engineering and biological perspective, focusing on the shear stress profiles they induce and the vascular pathology that is observed.

Correlation between the -1562C/T polymorphism in the matrix metalloproteinase-9 gene and hemorrhagic transformation of ischemic stroke

The aim of the present study was to investigate the correlation between the −1562C/T polymorphism in an intron of the matrix metalloproteinase-9 (MMP-9) gene and hemorrhagic transformation of ischemic stroke (IS). Using polymerase chain reaction-restriction fragment length polymorphism, the −1562C/T polymorphisms in 222 patients with IS were detected. The patients were divided into hemorrhagic transformation (HT; 84 cases) and non-hemorrhagic transformation (NHT) groups (138 cases) depending on the results from the susceptibility-weighted magnetic resonance imaging, which was performed between one and two weeks following stroke onset. The allele frequencies were subsequently compared. Baseline data of the two groups were comparable. The HT group exhibited a significantly lower frequency of the CT+TT genotype compared with the NHT group (17.86 vs. 30.43%, P<0.05). In addition, the frequency of T allele was significantly lower in the HT group compared with the NHT group (8.93 vs. 15.94%, P<0.05). Therefore, the results indicated that the −1562C/T polymorphism in the MMP-9 gene is correlated with hemorrhagic transformation of IS in the population studied. Furthermore, the T allele may be a protective factor for hemorrhagic transformation of IS in this population.

Differential MMP-9 activity in CD34⁺progenitor cell-derived foam cells from diabetic and normoglycemic patients

BACKGROUND

Upon coincubation with platelet aggregates, CD34(+) progenitor cells have the potential to differentiate into foam cells. There is evidence that progenitor cells from diabetic and nondiabetic patients have different properties, which may affect the patients' prognosis. In this study we investigated an in vitro model of foam cell formation based on patient-derived CD34(+) progenitor cells. We analyzed the growth characteristics as well as the M-CSF-release and matrix metalloproteinase (MMP) synthesis from CD34(+) progenitor cell-derived foam cells originating from diabetic and nondiabetic patients.

METHODS AND RESULTS

Bone marrow samples were obtained from 38 patients who were elected for thoracic surgery. CD34(+) progenitor cells from diabetic and nondiabetic patients were isolated and incubated with platelets from healthy volunteers. Foam cell formation was confirmed by immunostaining (CD68) and quantified by light microscopy. Whereas the absolute number of foam cells was not affected, the negative slope in the growth curve was seen significantly later in the diabetic group. In supernatants derived from"diabetic" CD34(+) progenitor cells, MMP-9 was significantly enhanced, whereas MMP-2 activity or M-CSF-release was not affected significantly.

CONCLUSION

In a coculture model of CD34(+) progenitor cells with platelets, we show for the first time that"diabetic" CD34(+) progenitor cells exhibit functional differences in their differentiation to foam cells concerning growth characteristics and release of MMP-9.

Matrix metalloproteinase-9 expression in carotid atherosclerotic plaque and contrast-enhanced MRI in a swine model

BACKGROUND

A swine model of carotid atherosclerosis may greatly facilitate the identification of imaging characteristics of vulnerable plaques and the preclinical evaluation of endovascular intervention. In this study we assess the association of matrix metalloproteinase (MMP)-9 expression and neovascularity in carotid atherosclerotic plaques with MRI patterns in a swine model.

METHODS

Carotid atherosclerosis models were created in miniswine using a combination of partial ligation and a high cholesterol diet. The animals were imaged in a 1.5 T MR scanner at 3 months and carotid arteries were obtained for histopathological and immunohistochemical examination. Contrast-enhanced T1-weighted imaging (T1WI) was used to match the histology findings. The contrast-to-noise ratio (CNR) of the plaques on T1WI and contrast-enhanced T1WI were measured and the association of MMP-9 expression and neovascularity in the carotid plaque with CNR on MRI was analyzed.

RESULT

Forty carotid artery segments were matched between MRI and histology. All segments were advanced carotid atherosclerotic plaques. The matched contrast-enhanced T1WI and histology slices showed good correlation for ratio of plaque size to lumen diameter (r=0.94, p<0.001). Plaque CNR on contrast-enhanced T1WI was higher in plaques with strong MMP-9 expression than in those with weak MMP-9 expression (p=0.05). Plaque CNR on contrast-enhanced T1WI was also higher in plaques with marked neovascularization than in those without (p=0.02).

CONCLUSIONS

Increased plaque CNR on contrast-enhanced T1WI is associated with MMP-9 expression and neovascularization in carotid atherosclerotic plaques and may be used to identify vulnerable plaques.