Coordinated effects of fibroblast growth factor-2 on expression of fibrillar collagens, matrix metalloproteinases, and tissue inhibitors of matrix metalloproteinases by human vascular smooth muscle cells. Evidence for repressed collagen production and activated degradative capacity

Scleral remodeling in early adulthood: the role of FGF-2

Emmetropization, a natural process of ocular elongation, is closely associated with scleral remodeling. The Fibroblast growth factor-2 (FGF-2) was reported involved in scleral remodeling in myopia models. Herein, we aimed to investigate the role of scleral fibroblast-to-myofibroblast differentiation and FGF-2 in scleral remodeling during maturation. Our findings revealed that the posterior scleral fibroblasts (SFs) from mature guinea pigs exhibit increased stiffness compared to those from young guinea pigs. Moreover, mature SFs displayed decreased cell proliferation but increased levels of α-SMA, matrix metalloproteinase 2 (MMP2), and collagen 1, when compared to young SFs. Additionally, the mRNA expression of scleral Fgf-2, Fgf receptor 1 (Fgfr1), Fgfr2, Fgfr3, and Fgfr4 was increased in mature SFs. Notably, exogenous FGF-2 showed increased cell proliferation and led to decreased expression of α-SMA, MMP2, and collagen 1 in mature SFs. Overall, our findings highlight the influence of maturation on SFs from posterior scleral shells, resulting in increased stiffness and the manifestation of fibroblast-to-myofibroblast differentiation during development. Exogenous FGF-2 increased cell proliferation and reversed the age-related fibroblast-to-myofibroblast differentiation, suggesting a potential role of FGF-2 in regulating scleral remodeling.

Camelina lipid droplets as skin delivery system promotes wound repair by enhancing the absorption of hFGF2

Human basic fibroblast growth factor (hFGF2) is widely recognized for accelerating skin wound healing in both animal models and randomized clinical trials. However, the low skin permeation and bioavailability of hFGF2 remain the most limiting factors in the pharmacological application. For the first time, Camelina Lipid Droplets (CLD) delivery system was displayed important virtue, by promoting the skin absorption of hFGF2, which is a key factor that accelerates the skin wound repair, and provide a new alternative for skin therapy. In this study, we used the CLD as a safer material to prepare the nanoparticles, which were characterized by size and morphology. Our data revealed that particle sizes of Camelina Lipid Droplets linked to hFGF2 (CLD-hFGF2) were around 133.5 nm; it also displayed that the complex of CLD-hFGF2 penetrates the skin barrier in deeper than an individual hFGF2. This suggests that once the hFGF2 is fixed onto the surface of CLD, it can cross the stratum corneum and play a therapeutic role into the dermis. Furthermore, we demonstrated that CLD-hFGF2 enhances fibroblast migration, and significantly improves skin regeneration for accelerating wound healing without any significant toxicity. This paper highlights the importance of CLD as an emerging delivery system; it is also providing a new and applicable therapeutic research direction through enhancing the skin permeation of hFGF2 to accelerate wound healing.

Visfatin: An emerging adipocytokine bridging the gap in the evolution of cardiovascular diseases

Visfatin/nicotinamide phosphoribosyltransferase (NAMPT) is an adipokine expressed predominately in visceral fat tissues. High circulating levels of visfatin/NAMPT have been implicated in vascular remodeling, vascular inflammation, and atherosclerosis, all of which pose increased risks of cardiovascular events. In this context, increased levels of visfatin have been correlated with several upregulated pro-inflammatory mediators, such as IL-1, IL-1Ra, IL-6, IL-8, and TNF-α. Furthermore, visfatin is associated with leukocyte recruitment by endothelial cells and the production of adhesion molecules such as vascular cell adhesion molecule 1, intercellular cell adhesion molecule 1, and E-selectin, which are well known to mediate the progression of atherosclerosis. Moreover, diverse angiogenic factors have been found to mediate visfatin-induced angiogenesis. These include matrix metalloproteinases, vascular endothelial growth factor, monocyte chemoattractant protein 1, and fibroblast growth factor 2. This review aims to provide a comprehensive overview of the pro-inflammatory and angiogenic actions of visfatin, with a focus on the pertinent signaling pathways whose dysregulation contributes to the pathogenesis of atherosclerosis. Most importantly, some hypotheses regarding the integration of the aforementioned factors with the plausible atherogenic effect of visfatin are put forth for consideration in future studies. The pharmacotherapeutic potential of modulating visfatin's roles could be important in the management of cardiovascular disease, which continues to be the leading cause of death worldwide.

A new nanoscale transdermal drug delivery system: oil body-linked oleosin-hEGF improves skin regeneration to accelerate wound healing

Background

Epidermal growth factor (EGF) can promote cell proliferation as well as migration, which is feasible in tissue wound healing. Oil bodies have been exploited as an important platform to produce exogenous proteins. The exogenous proteins were expressed in oil bodies from plant seeds. The process can reduce purification steps, thereby significantly reducing the purification cost. Mostly, the diameter of oil body particle ranges between 1.0 and 1.5 µm in the safflower seeds, however, it reduces to 700–1000 nm in the transgenic safflower seeds. The significant reduction of particle size in transgenic seeds is extremely beneficial to skin absorption.

Results

The diameter of oil body in the transgenic safflower seeds was recorded in the range of 700–1000 nm. The smaller particle size improved their skin absorption. The expression level of oleosin-hEGF-hEGF in T3 transgenic seeds was highest at 69.32 mg/g of seeds. The oil body expressing oleosin-hEGF-hEGF had significant proliferative activity on NIH/3T3 cells and improved skin regeneration thereby accelerating wound healing in rats. The wound coverage rate exceeded 98% after treatment for 14 days with oil body expressing oleosin-hEGF-hEGF, while the saline without EGF group and wild type oil body group both showed less than 80%. The neonatal fibroblast and collagen were found to be increased in the safflower oil body expressing oleosin-hEGF-hEGF treatment group. TGF-β1, bFGF and VEGF were noted as important growth factors in the repair of cutaneous wounds. Their expression level increased after 4 and 7 day treatment, but decreased after 14 days. Therefore, it can promote skin regeneration to accelerate wounds healing.

Conclusions

The expression of oleosin-hEGF-hEGF in T3 transgenic seeds was 80.43 ng/μL oil body. It had significant proliferative activity on NIH/3T3 cells and improved skin regeneration to accelerate wound healing in rats. The expression process of TGF-β1, bFGF and VEGF increased at first and then gradually declined.

Electronic supplementary material

The online version of this article (10.1186/s12951-018-0387-5) contains supplementary material, which is available to authorized users.

Vascular Imaging of Matrix Metalloproteinase Activity as an Informative Preclinical Biomarker of Drug-induced Vascular Injury

Lack of biomarkers specific to and either predictive or diagnostic of drug-induced vascular injury (DIVI) continues to be a major obstacle during drug development. Biomarkers derived from physiologic responses to vessel injury, such as inflammation and vascular remodeling, could make good candidates; however, they characteristically lack specificity for vasculature. We evaluated whether vascular remodeling-associated protease activity, as well as changes to vessel permeability resulting from DIVI, could be visualized ex vivo in affected vessels, thereby allowing for visual monitoring of the pathology to address specificity. We found that visualization of matrix metalloproteinase activation accompanied by increased vascular leakage in the mesentery of rats treated with agents known to induce vascular injury correlated well with incidence and severity of histopathological findings and associated inflammation as well as with circulating levels of tissue inhibitors of metalloproteinase 1 and neutrophil gelatinase-associated lipocalin. The weight of evidence approach reported here shows promise as a composite DIVI preclinical tool by means of complementing noninvasive monitoring of circulating biomarkers of inflammation with direct imaging of affected vasculature and thus lending specificity to its interpretation. These findings are supportive of a potential strategy that relies on translational imaging tools in conjunction with circulating biomarker data for high-specificity monitoring of VI both preclinically and clinically.

Fibroblast Growth Factor 9 Imparts Hierarchy and Vasoreactivity to the Microcirculation of Renal Tumors and Suppresses Metastases

Tumor vessel normalization has been proposed as a therapeutic paradigm. However, normal microvessels are hierarchical and vasoreactive with single file transit of red blood cells through capillaries. Such a network has not been identified in malignant tumors. We tested whether the chaotic tumor microcirculation could be reconfigured by the mesenchyme-selective growth factor, FGF9. Delivery of FGF9 to renal tumors in mice yielded microvessels that were covered by pericytes, smooth muscle cells, and a collagen-fortified basement membrane. This was associated with reduced pulmonary metastases. Intravital microvascular imaging revealed a haphazard web of channels in control tumors but a network of arterioles, bona fide capillaries, and venules in FGF9-expressing tumors. Moreover, whereas vasoreactivity was absent in control tumors, arterioles in FGF9-expressing tumors could constrict and dilate in response to adrenergic and nitric oxide releasing agents, respectively. These changes were accompanied by reduced hypoxia in the tumor core and reduced expression of the angiogenic factor VEGF-A. FGF9 was found to selectively amplify a population of PDGFRβ-positive stromal cells in the tumor and blocking PDGFRβ prevented microvascular differentiation by FGF9 and also worsened metastases. We conclude that harnessing local mesenchymal stromal cells with FGF9 can differentiate the tumor microvasculature to an extent not observed previously.

Enamel matrix proteins exhibit growth factor activity: A review of evidence at the cellular and molecular levels

Enamel matrix derivative (EMD) is a commercially available protein extract, mainly comprising amelogenins. A number of other polypeptides have been identified in EMD, mostly growth factors, which promote cementogenesis and osteogenesis during the regeneration processes through the regulation of cell proliferation, differentiation and activity; however, not all of their functions are clear. Enamel extracts have been proposed to have numerous activities such as bone morphogenetic protein- and transforming growth factor β (TGF-β)-like activity, and activities similar to those of insulin-like growth factor, fibroblast growth factor, platelet-derived growth factor, vascular endothelial growth factor and epidermal growth factor. These activities have been observed at the molecular and cellular levels and in numerous animal models. Furthermore, it has been suggested that EMD contains an unidentified biologically active factor that acts in combination with TGF-β1, and several studies have reported functional similarities between growth factors and TGF-β in cellular processes. The effects of enamel extracts on the cell cycle and biology are summarized and discussed in this review.

Vascular extracellular matrix in atherosclerosis

The extracellular matrix (ECM) is an essential component of the human body that is responsible for the proper function of various organs. Changes in the ECM have been implicated in the pathogenesis of several cardiovascular conditions including atherosclerosis, restenosis, and heart failure. Matrix components, such as collagens and noncollagenous proteins, influence the function and activity of vascular cells, particularly vascular smooth muscle cells and macrophages. Matrix proteins have been shown to be implicated in the development of atherosclerotic complications, such as plaque rupture, aneurysm formation, and calcification. ECM proteins control ECM remodeling through feedback signaling to matrix metalloproteinases (MMPs), which are the key players of ECM remodeling in both normal and pathological conditions. The production of MMPs is closely related to the development of an inflammatory response and is subjected to significant changes at different stages of atherosclerosis. Indeed, blood levels of circulating MMPs may be useful for the assessment of the inflammatory activity in atherosclerosis and the prediction of cardiovascular risk. The availability of a wide variety of low-molecular MMP inhibitors that can be conjugated with various labels provides a good perspective for specific targeting of MMPs and implementation of imaging techniques to visualize MMP activity in atherosclerotic plaques and, most interestingly, to monitor responses to antiatheroslerosis therapies. Finally, because of the crucial role of ECM in cardiovascular repair, the regenerative potential of ECM could be successfully used in constructing engineered scaffolds and vessels that mimic properties of the natural ECM and consist of the native ECM components or composite biomaterials. These scaffolds possess a great promise in vascular tissue engineering.

Antifibrotic response of cardiac fibroblasts in hypertensive hearts through enhanced TIMP-1 expression by basic fibroblast growth factor

BACKGROUND

Cardiac fibroblasts (CFs) play a pivotal role in the development of myocardial fibrosis. We previously demonstrated that direct injection of basic fibroblast growth factor (bFGF) into the hypertensive Dahl salt-sensitive (DS) rat heart prevented systolic dysfunction and left ventricular dilation effectively. However, the precise role played by bFGF in fibrotic response of CFs remains unclear. We suggested potential effects of bFGF on the fibrotic response of CFs in vitro.

METHODS AND RESULTS

Histopathologic assessment of cardiac fibrosis demonstrated a marked decline in the extent of perivascular and interstitial fibrosis in bFGF-injected hypertensive DS rat hearts. CFs harvested from the hearts of noninjected DS rats demonstrated a significantly increased messenger RNA (mRNA) expression of matrix metalloproteinase (MMP)-2, MMP-9, and both collagen I and III. In contrast, bFGF treatment in the CFs induced a marked increase in tissue inhibitor of MMP (TIMP)-1 expression and a marked decline in MMP-9 activation. bFGF also induced a decline in α-smooth muscle actin and collagen I and III mRNA expression in the CFs accompanied by inhibited differentiation of CFs into myofibroblasts. Small interfering RNA targeting FGF receptor 1 confirmed a specific interference of the mRNA expression changes elicited by bFGF. In vivo examination confirmed many TIMP-1-positive CFs in perivascular spaces of bFGF-injected hearts.

CONCLUSIONS

Up-regulated TIMP-1 expression and down-regulated MMP-9 activation by bFGF in CFs could prevent excessive ECM degradation and collagen deposition in perivascular spaces effectively, leading to prevention of cardiac fibrosis during hypertensive heart failure.

SUMMARY

Cardiac fibroblasts (CFs) play a pivotal role in myocardial fibrosis. The precise role of CFs in fibrotic response played by growth factors remains unclear. Our results indicates that basic fibroblast growth factor could up-regulate TIMP-1 expression and down-regulate MMP-9 activation in CFs in perivascular spaces, leading to inhibited progression of cardiac fibrosis during hypertensive heart failure.

The extracellular matrix is a novel attribute of endothelial progenitors and of hypoxic mature endothelial cells

Extracellular matrix (ECM) production is critical to preserve the function and integrity of mature blood vessels. Toward the engineering of blood vessels, studies have centered on ECM production by supporting cells, whereas few studies implicate endothelial cells (ECs) with ECM synthesis. Here, we elucidate variations between cultured human arterial, venous, and progenitor ECs with respect to ECM deposition assembly, composition, and response to biomolecular and physiological factors. Our studies reveal that progenitor ECs, endothelial colony-forming cells (ECFCs), deposit collagen IV, fibronectin, and laminin that assemble to an organized weblike structure, as confirmed by decellularized cultures. Mature ECs only express these ECM proteins intracellularly. ECFC-derived ECM is abrogated in response to TGFβ signaling inhibition and actin cytoskeleton disruption. Hypoxic (1%) and physiological (5%) O(2) tension stimulate ECM deposition from mature ECs. Interestingly, deposition of collagen I is observed only under 5% O(2) tension. ECM production from all ECs is found to be regulated by hypoxia-inducible factors 1α and 2α but differentially in the different cell lines. Collectively, we suggest that ECM deposition and assembly by ECs is dependent on maturation stage and oxygen supply and that these findings can be harnessed to advance engineered vascular therapeutics.

Increased plasma basic fibroblast growth factor is associated with coronary heart disease in adult type 2 diabetes mellitus

Basic fibroblast growth factor (bFGF) is a potent endothelial and smooth muscle cell mitogen that does not normally circulate. Plasma bFGF-like bioactivity was increased in association with persistent microalbuminuria (a risk marker for cardiovascular disease) in adult type 2 diabetes mellitus. In the present study, we tested whether baseline plasma bFGF immunoreactivity (IR) predicts the occurrence of a subset of cardiovascular disease outcomes in adults with advanced type 2 diabetes mellitus from the Veterans Affairs Diabetes Trial (mean: age, 59 years; diabetes duration, 11 years; baseline hemoglobin A(1c), 9.5%). Plasma bFGF-IR was determined with a sensitive and specific 2-site enzyme-linked immunoassay in 399 patients at the baseline visit. These results were then evaluated as possible predictors of the occurrence of prespecified cardiovascular or coronary heart disease end points. There was a borderline-significant association (P = .07) between plasma bFGF-IR and the main study cardiovascular disease outcome (myocardial infarction, congestive heart failure, cerebrovascular accident, amputation, cardiovascular death, coronary, cerebrovascular or peripheral revascularization, and inoperable coronary artery disease). Plasma bFGF-IR was significantly associated with the occurrence of coronary heart disease (P = .01). After adjusting for clinical risk factors, bFGF (hazard ratio [HR], 1.013; 95% confidence interval [CI], 1.007-1.019; P < .0001), prior macrovascular event (HR, 3.55; 95% CI, 2.154-5.839; P < .0001), and duration of diabetes (HR, 1.041; 95% CI, 1.012-1.071; P = .0055) were all significantly associated with time to first postrandomization coronary heart disease occurrence. These results suggest that increased plasma bFGF-IR may be a novel risk marker for coronary heart disease occurrence in adult men with advanced type 2 diabetes mellitus.

Effects of bFGF on suppression of collagen type I accumulation and scar tissue formation during wound healing after mucoperiosteal denudation of rat palate

OBJECTIVE

The purpose of this study was to evaluate the effect of basic fibroblast growth factor (bFGF) on collagen changes after mucoperiosteal denudation of rat palate.

MATERIAL AND METHODS

A total of 36 male Wistar rats were divided into control, scar, sham, and bFGF groups. In the scar, sham, and bFGF groups, lateral palatal mucoperiosteum was excised to form scar tissue on the palate. In the bFGF group, bFGF solution was injected into the operated area 1 week postoperatively. At 6 weeks postoperatively, the distribution of collagen type I and the 3-dimensional structure of collagen fibers were investigated under immunofluorescent and scanning electron microscopy.

RESULT

In the bFGF group, weakly immunostained submucosa was clearly distinguishable from the strongly immunostained cervical periodontal ligament and gingiva. Collagen fibers running from submucosal tissue into the surface of underlying palatal bone comprised loosely arranged collagen fibrils. Lumen structures in collagen fibers resembled those in the control group.

CONCLUSION

Administration of bFGF for suppression of collagen type I generation could suppress scar tissue formation and reduce connective strength with adjacent teeth and palatal bone.

Receptor-interacting protein 2 is a marker for resolution of peritoneal dialysis-associated peritonitis

There are no predictive factors for peritoneal dialysis-associated peritonitis; however, its resolution correlates with a cell-mediated Th1 immune response. We tested the hypothesis that induction of receptor-interacting protein 2 (RIP2), an assumed kinase linked with Th1 responses, is a useful marker in this clinical setting. Basal RIP2 expression was measured in human immune cells and during dialysis-associated peritonitis. RIP2 increased with bacterial toxin cell activation and the temporal profile for this differed depending on immune cell involvement in the innate or adaptive phases of the response. Importantly, RIP2 expression increased in peritoneal immune cells during dialysis-associated peritonitis and this upregulation correlated with clinical outcome. An early induction in peritoneal CD14(+) cells correlated with rapid resolution, whereas minimal induction correlated with protracted infection and with catheter loss in 36% of patients. These latter patients had higher levels of MCP-1 consistent with a delayed transition from innate to adaptive immunity. Our study shows that upregulation of RIP2 is a useful marker to monitor dialysis-associated peritonitis and in predicting the clinical outcome of these infections.

Effects of heparin on the production of homocysteine-induced extracellular matrix metalloproteinase-2 in cultured rat vascular smooth muscle cells

OBJECTIVE

To study the effects of heparin on the production of homocysteine-induced extracellular matrix metalloproteinase-2 (MMP-2) in cultured rat vascular smooth muscle cells.

METHODS

The effects of different homocysteine levels (0 micromol/L to 1000 micromol/L) on MMP-2 production and the effects of different heparin concentrations (0 microg/mL to 100 microg/mL) on homocysteine-induced MMP-2 in cultured rat vascular smooth muscle cells were examined using gelatin zymography and Western blotting. The changes in MMP-2 were further compared with various treatments for 24 h, 48 h and 72 h.

RESULTS

Homocysteine (50 micromol/L to 1000 micromol/L) increased the production of MMP-2 significantly in a dose-dependent manner. Increased production of MMP-2 induced by homocysteine was reduced by the extracellular addition of heparin in a dose-dependent manner. Production of MMP-2 with various treatment regimens for 72 h was greater than for 24 h and 48 h.

CONCLUSIONS

Extracellular addition of heparin decreased homocysteine-induced MMP-2 secretion. Data suggest a mechanism by which hyperhomocysteinemia is involved in the pathogenesis of coronary artery disease and demonstrate a beneficial effect of heparin on these conditions.

Matrix metalloproteinases: influence on smooth muscle cells and atherosclerotic plaque stability

Atherosclerotic plaque rupture, with subsequent occlusive thrombosis, is the underlying cause of most cases of sudden cardiac death. Matrix metalloproteinases (MMPs) are thought to mediate the progression of stable atherosclerotic lesions to an unstable phenotype that is prone to rupture through the destruction of strength-giving extracellular matrix (ECM) proteins. Smooth muscle cells secrete and deposit ECM proteins and are, therefore, considered protective against atherosclerotic plaque destabilization. However, similar to inflammatory cells (e.g., macrophages), smooth muscle cells release numerous MMPs that are capable of digesting ECM proteins. Thus, the interaction of smooth muscle cells and MMPs in atherosclerotic plaques is complex and not fully understood. Recently, research into the roles of MMPs and their endogenous inhibitors (tissue inhibitors of metalloproteinases), and their effects on smooth muscle behavior during plaque destabilization has been aided by the development of reproducible animal models of plaque instability. A plethora of studies has demonstrated that MMPs directly modulate smooth muscle behavior with both beneficial and deleterious effects on atherosclerotic plaque stability, in addition to their canonical effects on ECM remodeling. Consequently, broad-spectrum MMP inhibition may inhibit plaque-stabilizing mechanisms, such as smooth muscle cell growth, while conversely retarding ECM destruction and subsequent rupture. Hence the development of selective MMP inhibitors, that spare inhibitory effects on smooth muscle cell function, may be useful therapies to prevent plaque rupture and in this regard MMP-12 appears to be a particularly attractive target.

Chinese yellow wine inhibits production of homocysteine-induced extracellular matrix metalloproteinase-2 in cultured rat vascular smooth muscle cells

BACKGROUND & AIMS

Regular consumption of moderate amounts of Chinese yellow wine is associated with a reduced risk of coronary disease. Matrix metalloproteinases (MMPs) that participate in extracellular matrix degradation have been involved in atherosclerotic plaque growth and instability. The present research aimed to study the effects of Chinese yellow wine on the production of homocysteine (Hcy)-induced extracellular MMP-2 in cultured rats vascular smooth muscle cells (VSMCs).

METHODS

We examined the effects of different Hcy levels (0-1000 micromol/l) on MMP-2 production, and the effects of Chinese yellow wine with low alcohol concentrations (12-19%) on Hcy-induced MMP-2 in cultured rat (VSMCs) using gelatin zymography and western blotting. We further compared the changes of MMP-2 under various treatments for 12, 24 and 48 h.

RESULTS

Hcy (50-1000 micromol/l) increased the production of MMP-2 significantly in a dose-dependent manner. Increased production of MMP-2 induced by Hcy was reduced by extracellularly added Chinese yellow wine. Production of MMP-2 under various treatments for 48 h increased more than 12 and 24 h.

CONCLUSIONS

Extracellularly added Chinese yellow wine decreased Hcy-induced MMP-2 secretion. The inhibitory effect of yellow wine on the activation of MMP-2 might contribute to their beneficial effects on the cardiovascular system.

Splenic vasculopathy in portal hypertension patients

AIM: To investigate the interaction between portal hypertension, splanchnic hyperdynamic circulation and splanchnic vasculopathy by observing splenic arterial and venous pathological changes and the ro1e of extra-cellular matrix in the pathogenesis of portal hypertensive vasculopathy by measuring the expression of type Ι and type III procollagen mRNA in splenic venous walls of portal hypertensive patients.

METHODS: Morphological changes of splenic arteries and veins taken from portal hypertensive patients (n = 20) and normal controls (n = 10) were observed under optical and electron microscope. Total RNA was extracted and the expression of type Ι and type III procollagen mRNA in splenic venous walls of portal hypertensive patients (n = 20) was semi-quantitatively detected using reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS: Under optical microscope, splenic arterial intima was destroyed and internal elastic membrane and medial elastic fibers of the splenic arterial walls were degenerated and broken. Splenic venous intima became remarkably thick. Endothelia1 cells were not intact with formation of mural thrombus. The tunica media became thickened significantly due to hypertrophy of smooth muscles. Fibers and connective tissues were increased obviously. Under electron microscope, smooth muscle cells of the splenic arteries were degenerated and necrotized. Phenotypes of smooth muscle cells changed from constrictive into synthetic type. Red blood cells and platelets accumulated around the damaged endothelial cells. Synthetic smooth muscle cells were predominant in splenic veins and their cytoplasma had plentiful rough endoplasmic reticulum ribosomes and Golgi bodies. Along the vascular wall, a lot of collagen fibers were deposited, the intima was damaged and blood components accumulated. There was no significant difference in the expression of type I procollagen mRNA in splenic venous wall between the patients with portal hypertension and those without portal hypertension (P > 0.05), but the expression of type III procoagen mRNA was significantly stronger in the patients with portal hypertension than in those without portal hypertension (P < 0.01).

CONCLUSION: Type III procollagen and collagen might be important extra-cellular matrix resulting in neointimal formation and vascular remodeling in the pathogenesis of portal hypertensive vasculopathy. The pathological changes in splenic arteries and veins exist in portal hypertension patients. There might be an interaction between portal hypertension, splanchnic hyperdynamic circulation and splanchnic vasculopathy.

Effects of folic acid and magnesium on the production of homocysteine-induced extracellular matrix metalloproteinase-2 in cultured rat vascular smooth muscle cells

BACKGROUND

Hyperhomocysteinemia is an independent risk factor of coronary artery disease, but some studies have shown that patients with hyperhomocysteinemia are not prone to atherosclerosis. The aim of this study was to test whether homocysteine increases the production of matrix metalloproteinase-2 (MMP-2) and if extracellular additional magnesium and folic acid alters MMP-2 secretion.

METHODS AND RESULTS

Gelatin zymography and western blotting were used to investigate the effects of different homocysteine levels (0-5,000 micromol/L) on MMP-2 production, and the effects of different folic acid concentrations (0-10 micromol/L) and magnesium concentrations (0-3.0 mmol/L) on homocysteine-induced MMP-2 in cultured rat vascular smooth muscle cells. Furthermore, the changes in MMP-2 were compared under various treatments for 24 h, 48 h and 72 h. Homocysteine (50-1,000 micromol/L) increased the production of MMP-2 significantly in a dose-dependent manner and at a high level (5,000 micromol/L) reduced the production of MMP-2. Increased production of MMP-2 induced by homocysteine was reduced by additional extracellular folic acid in a dose-dependent manner. Magnesium also reduced the increase of MMP-2 production induced by homocysteine. Production of MMP-2 under various treatments for 72 h increased more than during 24 or 48 h.

CONCLUSIONS

Homocysteine (50-1,000 micromol/L) significantly increased the production of MMP-2 in a dose-dependent manner. Added extracellular folic acid and magnesium decreased the homocysteine-induced MMP-2 secretion. These data suggest a beneficial effect of folic acid and magnesium on the pathogenesis of coronary artery disease.

Pioglitazone inhibits MMP-1 expression in vascular smooth muscle cells through a mitogen-activated protein kinase-independent mechanism

Antidiabetic drug thiazolidinedione (TZD) also has anti-atherogenic effects. Among these effects, inhibition of smooth muscle cell (SMC) migration is considered to be essential. However, the mechanism whereby TZD inhibits SMC migration is not well understood. Since it is known that matrix metalloproteinases (MMPs) play a permissive role for SMC migration, we determined if TZD inhibits the upregulation of MMP-1 expression in SMCs by oxidized LDL (oxLDL), a potent stimulator for atherogenesis. Results showed that oxLDL markedly stimulated MMP-1 secretion, mRNA expression, and MMP-1 promoter activity, but pioglitazone significantly inhibited the oxLDL-upregulated MMP-1 expression. In an attempt to explore the signaling mechanism by which pioglitazone inhibits the oxLDL-upregulated MMP-1 expression, we found that extracellular signal-regulated kinase (ERK) and c-Jun-N-terminal kinase (JNK) pathways were required for the oxLDL-stimulated MMP-1 expression, but pioglitazone failed to antagonize the activation of ERK and JNK by oxLDL. Finally, our AP-1 activity assay showed that pioglitazone inhibited oxLDL-stimulated c-Jun activity. Taken together, the present study indicates that pioglitazone inhibits oxLDL-stimulated MMP-1 expression in VSMCs by inhibiting c-Jun transcriptional activity through a mitogen-activated protein kinase (MAPK)-independent mechanism.

Dual role of matrix metalloproteinases (matrixins) in intimal thickening and atherosclerotic plaque rupture

Intimal thickening, the accumulation of cells and extracellular matrix within the inner vessel wall, is a physiological response to mechanical injury, increased wall stress, or chemical insult (e.g., atherosclerosis). If excessive, it can lead to the obstruction of blood flow and tissue ischemia. Together with expansive or constrictive remodeling, the extent of intimal expansion determines final lumen size and vessel wall thickness. Plaque rupture represents a failure of intimal remodeling, where the fibrous cap overlying an atheromatous core of lipid undergoes catastrophic mechanical breakdown. Plaque rupture promotes coronary thrombosis and myocardial infarction, the most prevalent cause of premature death in advanced societies. The matrix metalloproteinases (MMPs) can act together to degrade the major components of the vascular extracellular matrix. All cells present in the normal and diseased blood vessel wall upregulate and activate MMPs in a multistep fashion driven in part by soluble cytokines and cell-cell interactions. Activation of MMP proforms requires other MMPs or other classes of protease. MMP activation contributes to intimal growth and vessel wall remodeling in response to injury, most notably by promoting migration of vascular smooth muscle cells. A broader spectrum and/or higher level of MMP activation, especially associated with inflammation, could contribute to pathological matrix destruction and plaque rupture. Inhibiting the activity of specific MMPs or preventing their upregulation could ameliorate intimal thickening and prevent myocardial infarction.

Protease nexin-1: a cellular serpin down-regulated by thrombin in rat aortic smooth muscle cells

Protease nexin-1 (PN-1), a potent inhibitor of serine proteases, is present in vascular cells and forms complexes with thrombin, plasminogen activators, and plasmin. We examined the effect of thrombin on PN-1 expression by rat aortic smooth muscle cells (RASMCs). PN-1 expression was determined by measuring protein and mRNA levels, using respectively immunoblotting and semi-quantitative reverse transcriptase polymerase chain reaction (PCR). Thrombin down-regulated PN-1 expression in a dose- and time-dependent manner. This effect was mediated via the interaction of thrombin with its receptor protease activated receptor (PAR-1) since the peptide thrombin receptor activating peptide (TRAP) reduced PN-1 expression. PN-1 secreted by smooth muscle cells remained essentially associated to cell-surface glycosaminoglycans and was released from the cell surface by heparin. A lower amount of PN-1 was released by heparin from TRAP-stimulated versus unstimulated cells and correlated with a decreased capacity to inhibit thrombin. In addition, the ability to generate peri-cellular plasmin was increased in cells with a low PN-1 expression. Pre-treatment of smooth muscle cells with cycloheximide abolished the reduction of PN-1 expression by thrombin. Furthermore, conditioned media from thrombin-treated cells reproduced the effect of thrombin, suggesting that thrombin acted via the induction of auto/paracrine mediator(s). We observed that fibroblast growth factor-2 (FGF-2)-neutralizing antibodies abolished thrombin effect whereas FGF-2 reproduced it, indicating that FGF-2 is one of the involved mediator. Together, these results indicate that (i) PN-1 modulates the activity of endogenous and exogenous serine proteases in RASMCs, (ii) thrombin down-regulates PN-1 expression and thus may increase its own activity on cells.

Different Effects of Calcium Channel Blockers on Matrix Metalloproteinase-2 Expression in Cultured Rat Cardiac Fibroblasts

The cardiac effects of calcium channel blockers (CCBs) related to cardiac remodeling are inconsistent. Matrix metalloproteinases (MMPs) contribute to tissue remodeling. Cardiac fibroblasts play an important role in the regulation of collagen degradation by MMPs. Using gelatin zymography, Western blotting, Griess reagent, and a calcium kit-fluo 3, we investigated the effects of nifedipine, verapamil, diltiazem, and amlodipine on MMP-2 expression and further elucidate the mechanisms in cultured rat cardiac fibroblasts. Nifedipine increased and amlodipine decreased the expression of MMP-2; however, neither verapamil nor diltiazem altered MMP-2 expression. Nifedipine also increased nitrite production, and this increase was blunted by a nitric oxide (NO) synthases inhibitor (L-NAME). Nifedipine-induced MMP-2 expression was also blunted by L-NAME. An NO donor (sodium nitroprusside) induced MMP-2 expression. Data indicated that nifedipine might increase MMP-2 expression through a possible NO-dependent pathway. Amlodipine had no influence on nitrite production. The amlodipine-induced decrease of MMP-2 expression was abolished by two protein tyrosine kinase inhibitors, genistein and herbimycin A, indicating that amlodipine might decrease MMP-2 expression through a possible protein tyrosine kinase pathway. None of the four CCBs could alter the fluoscence intensity of fluo 3, indicating that the effects of CCBs on MMP-2 expression were independent of the variation in intracellular C2+ concentration. Our findings revealed that different CCBs exerted different effects on MMP-2 expression in cardiac fibroblasts.

Splenic angiopathy in portal hypertension

AIM: To investigate the relationship among portal hyper-tension, splanchnic hyperdynamic disturbances and splanchnic angiopathy by observing splenic arterial and venous pathological changes, to discuss the relationship between the abnormal local endothelium-derived vasoactive substances in portal veins and the activation of the pathway of mechanical force signal transduction in vascular endothelial cells by investigating the expression of eNOS ET-1 PKC NF-κB in vascular endothelial cells of portal hypertension, and to explore the role of extracellular matrix in the pathogenesis of portal hypertensive angiopathy by detecting the expression of type I and type II procollagen mRNA in splenic vein of portal hypertensive patients.

METHODS: Splenic arteries, veins from portal hypertensive patients (n = 20) and normal people (n = 10) were removed and observed under optical and electron microscopes. Immunohistochemistry and double labeling immunofluorescence combined with laser scanning confocal microscope were used to investigate the expression of eNOS ET-1 NF-κB and PKC protein in endothelial cells of splenic veins from portal hypertensive patients (n = 20) and portal veins from Wistar rats (n = 15). Total RNA was extracted and type I and type II procollagen mRNAs in splenic vein of portal hypertensive patients (n = 20) were examined by using the method of reverse transcriptional polymerase chain reaction with semiquantitative method.

RESULTS: The endothelium of splenic arteries was damaged and the internal elastic membrane and medial elastic fibers of the splenic artery wall were broken and degenerated. The endothelium of splenic veins was remarkably thickened and endothelial cells integrated with the formation of mural thrombus. The tunica media thickened significantly because of hypertrophy of smooth muscle. Fiber and connective tissues increased in amount. Under the electron microscope, atrophy, apoptosis and phenotypic changes were seen in smooth muscle cells of splenic arteries. There were some red blood cells and pathelets congregation around the damaged endothelium. Synthesis type of smooth muscle cells accounted for a large part of the total cells in splenic veins. There were plentiful rough endoplasmic reticulum and Golgi complex within the cytoplasm of smooth muscle cells. The endothelium of splenic veins was damaged, indicating that a lot of collagen fibers and some blood components accumulating around the damaged endotheliun.The positive signal of PKC was observed in cytoplasm and cell membrane.The PKC expression in endothelial cells in the splenic/portal vein of portal hypertensive patients/rats showed positive or strong positive signal, and positive signal were also observed in some smooth muscle cells in these specimens. But the PKC expression in endothelial cells in the control groups was negative or mild positive.The result of eNOS, ET-1 and NF-κB expression examined by double labeling immunofluorescence combined with laser scanning confocal microscope showed that the fluorescence were mostly localized in the endothelium of vessel. The intensity of fluorescence in the portal hypertensive patients/rats were significantly higher than that in control group. Human I procollagen mRNA expression of portal hypertensive patients in splenic vein showed a in-significant pattern with control group (P > 0.05), however, human III procollagen mRNA expression in portal hypertensive patients were much higher than that of control group (P < 0.01).

CONCLUSION: In this study, the mechanical signal pathway of endothelial cell is activated in portal hypertension and the upregulation of ET-1 and eNOS are related with the activation of this pathway. Type III procollagen and collagen may be one of the major extracellular matrix which deposits and results in neointimal formation and vascular remodeling in the pathogenesis of portal hypertensive vasopathy. Our research also shows that pathological changes of splenic arteries and veins are accompanied with portal hypertension. There may be an interactive relationship among portal hypertension, splanchnic hyperdynamic disturbances and splanchnic angiopathy.

Fibroblast growth factor-2 and remodeled type I collagen control membrane protrusion in human vascular smooth muscle cells: biphasic activation of Rac1

Plasma membrane protrusion is fundamental to cell motility, but its regulation by the extracellular environment is not well elucidated. We have quantified lamellipodial protrusion dynamics in human vascular smooth muscle cells exposed to fibroblast growth factor 2 (FGF-2) and type I collagen, two distinct ligands presented to vascular cells during arterial remodeling. Video microscopy revealed that FGF-2 stimulated a modest increase in lamellipodial protrusion rate that peaked within 15 min. This response was associated with immediate but transient activation of Rac1 and was inhibited in cells infected with retrovirus containing cDNA encoding dominant-negative Rac1. A 1-h exposure to FGF-2 also set up a second phase of more striking lamellipodial protrusion evident at 24-36 h. This delayed response was most pronounced when cells were on type 1 collagen and was associated with FGF-2-induced expression of collagenase-1 that localized to the edge of protruding lamellipodia. Moreover, late membrane protrusion was inhibited when cells were on collagenase-resistant type I collagen, implicating degraded collagen as a mediator. For cells on collagen, the immediate activation of Rac1 by FGF-2 was followed by a sustained wave of Rac1 activation that was inhibited when cleavage of the collagen triple helix was prevented and also by blockade of alpha(v)beta(3) integrin. We conclude that lamellipodial protrusion in smooth muscle cells can be regulated by waves of Rac1 activation, corresponding to the sequential presentation of FGF-2 and remodeled collagen. The findings thus reveal a previously unrecognized level of coordination among extracellular input that enables cells to maintain protrusive activity over prolonged periods.

Involvement of FGF-2 in the action of Emdogain on normal human osteoblastic activity

OBJECTIVE

The present study was designed to evaluate the pharmacological characteristics of Emdogain (EMD) on cell growth and cell activity in human osteoblasts.

METHODS

Cell proliferation as well as several gene and protein expressions were examined using reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) procedures in human osteoblastic cells (SaM-1) treated with EMD (30 microg ml(-1)).

RESULTS

Treatment of osteoblasts with EMD significantly stimulated cell proliferation and fibroblast growth factor (FGF)-2 expression but decreased alkaline phosphatase expression. In addition, increases in cyclooxygenase (COX)-2 expression and decreases in matrix metalloproteinases (MMP)-1 expression were observed in osteoblasts treated with EMD. The effects of EMD on FGF-2 and MMP-1 expressions were not observed in osteoblasts treated with NS-398, an inhibitor of COX-2. The decrease in MMP-1 mRNA by EMD was prevented by treatment with antisense oligodeoxynucleotide (AS-ODN) for FGF-2.

CONCLUSION

Emdogain showing both stimulation of cell proliferation and inhibition of cell differentiation has been shown to increase FGF-2 expression in the mediation of prostaglandin E2 and to decrease MMP-1 mRNA expression through the activation of FGF-2. FGF-2 may underlie in the action of EMD on osteoblasts during periodontal regeneration.

Effects of magnesium on the production of extracellular matrix metalloproteinases in cultured rat vascular smooth muscle cells

The precise correlation between magnesium and cardiovascular disease remains to be established. Matrix metalloproteinases (MMPs) are expressed in coronary arterial atherosclerotic lesions. MMP production in vascular smooth muscle cells (VSMCs) is stimulated by growth factors such as platelet-derived growth factor (PDGF). To assess the association between magnesium and MMPs, we examined the effects of different extracellular magnesium concentrations (0-3.0 mmol/l) on MMPs production in cultured rat VSMCs under basal and PDGF-stimulated conditions using gelatin zymography and western blotting. As magnesium is called a natural calcium antagonist, we further compared the effects of magnesium with some calcium antagonists. Magnesium reduced MMP-2 production dose-dependently at basal and PDGF-stimulated conditions in VSMCs. However, neither verapamil nor nifedipine influenced MMP-2 production under any conditions examined. The effect of magnesium on the production of MMP-2 was inhibited by two tyrosine kinase inhibitors-genistein and herbimycin A. The results of this study indicate that extracellularly added magnesium decreased MMPs secretion, which appears to be associated with protein tyrosine kinase.

Immunohistochemical study of endothelin-1 and matrix metalloproteinases in plexogenic pulmonary arteriopathy

The matrix metalloproteinases (MMPs) and endothelin-1, a potent vasoconstrictor and mitogen for smooth muscle cells, have been shown to be involved in the pathogenesis of various vascular disorders. However, the expression of endothelin-1 and the activation of MMPs have not been fully evaluated in plexogenic pulmonary arteriopathy (PPA). Immunohistochemical and confocal microscopic studies were conducted to evaluate the reactivity of lung tissue from six patients with pulmonary hypertension for alpha-smooth muscle actin (alpha-SMA), desmin, vimentin, factor VIII, endothelin-1, various types of MMPs (MMP-1, MMP-2, MMP-3, MMP-7 and MMP-9), membrane type-MMPs (MT-MMPs), tissue inhibitors of MMPs (TIMPs), and type IV collagen. Four major arterial morphological abnormalities were recognized in PPA: muscularization of pulmonary arterioles, onion-skin lesions, cellular and mature plexiform lesions, and atheromas in elastic pulmonary arteries. Reactivity for MMP-2 and MT-1-MMP was found in endothelial cells and, to a lesser extent, in myofibroblasts proliferating in various lesions of PPA. Increased expression of endothelin-1 was observed in the latter cells and in endothelial cells. Some myofibroblasts were positive for MMP-3 and MMP-7 in the vascular lesions except for mature plexiform lesions. MMP-1, MMP-9 and TIMP-2 tended to be positive only in the atheromatous lesions. Staining for type IV collagen showed focal thinning and discontinuities of the endothelial basement membrane in plexiform lesions. This study demonstrates colocalization of MMP-2 with MT-1-MMP and increased expression of endothelin-1 in various arterial lesions of PPA. These changes may play important roles in the remodeling of arterial structures, particularly of basement membranes, in this disorder.

Basic fibroblast growth factor decreases elastin gene transcription in aortic smooth muscle cells

The extracellular matrix (ECM) protein elastin plays an essential role in the cardiovascular system by imparting elasticity to blood vessel wall. In this study, we examined the effect of basic fibroblast growth factor (bFGF) on the expression of elastin in aortic smooth muscle cells (SMC) to gain insight into events associated with cardiovascular diseases. The results show that bFGF treatment of SMC causes a significant decrease in elastin mRNA and secreted tropoelastin levels. Nuclear run-on analyses demonstrate that the downregulation is due to a decrease in the level of elastin gene transcription. Transient transfections of SMC with wild-type and mutated elastin gene promoter/chloramphenicol acetyl transferase (CAT) constructs show that a previously identified activator protein-1-cAMP response element (AP1/CRE) (-564 to -558-bp) within the elastin promoter mediates the bFGF-dependent downregulation of elastin gene transcription in SMC. Addition of bFGF to SMC activates the extracellular signal-regulated kinases 1/2 (ERK1/2) resulting in their translocation into the nucleus and subsequent induction of Fra-1. The addition of PD-98059, an inhibitor of ERK1/2 kinase, abrogates the bFGF-dependent decrease of elastin mRNA in SMC. The described inhibitory effect of bFGF on elastin gene expression in SMC may significantly contribute to the inefficient repair of elastin in early stages of vascular wall injury.

Enhanced expression of fibroblast growth factors and receptor FGFR-1 during vascular remodeling in chronic obstructive pulmonary disease

Important characteristics of chronic obstructive pulmonary disease (COPD) include airway and vascular remodeling, the molecular mechanisms of which are poorly understood. We assessed the role of fibroblast growth factors (FGF) in pulmonary vascular remodeling by examining the expression pattern of FGF-1, FGF-2, and the FGF receptor (FGFR-1) in peripheral area of lung tissues from patients with COPD (FEV(1) < or = 75%; n = 15) and without COPD (FEV(1) > or = 85%; n = 13). Immunohistochemical staining results were evaluated by digital video image analysis as well as by manual scoring. FGF-1 and FGFR-1 were detected in vascular smooth muscle (VSM), airway smooth muscle, and airway epithelial cells. FGF-2 was localized in the cytoplasm of airway epithelium and in the nuclei of airway smooth muscle, VSM, and endothelial cells. In COPD cases, an unequivocal increase in FGF-2 expression was observed in VSM (3-fold, P = 0.001) and endothelium (2-fold, P = 0.007) of small pulmonary vessels with a luminal diameter under 200 micro m. In addition, FGFR-1 levels were elevated in the intima (1.5-fold, P = 0.05). VSM cells of large (> 200 micro m) pulmonary vessels showed increased staining for FGF-1 (1.6-fold, P < 0.03) and FGFR-1 (1.4-fold, P < 0.04) in COPD. Pulmonary vascular remodeling, assessed as the ratio of alpha-smooth muscle actin staining and vascular wall area with the lumen diameter, was increased in large vessels of patients with COPD (P = 0.007) and was inversely correlated with FEV(1) values (P < 0.007). Our results suggest an autocrine role of the FGF-FGFR-1 system in the pathogenesis of COPD-associated vascular remodeling.

Expression of angiogenesis and angiogenic factors in human aortic vascular disease

BACKGROUND

This paper presents an investigation into the expression of endothelial cells and vascular endothelial growth factor (VEGF) in the aortic wall in vascular diseases such as atherosclerotic abdominal aortic aneurysm (AAAA), inflammatory abdominal aortic aneurysm (IAAA), and aortic occlusive disease (AOD) to determine whether the differences in both neovascularization and angiogenic factor expression are related to the pathogenesis of aortic vascular disease.

MATERIALS AND METHODS

Surgical specimens of aorta (10 IAAA, 13 AAAA, 6 AOD) were studied pathologically and immunohistochemically. Representative sections of aorta were stained with hematoxylin-eosin, elastica von Gieson, CD34, and VEGF antibody. CD34-positive microvessels and VEGF-positive cells in the media and adventitia were counted, respectively.

RESULTS

CD34-positive microvessels were detected in IAAA > AAAA > AOD (one-way analysis of variance (ANOVA), P < 0.0001). VEGF expression was widely detected in macrophages, monocytes, and smooth muscle cells of IAAA and AAAA; however, it was hardly recognized in AOD. VEGF-positive cells were detected in IAAA > AAAA > AOD specimens (ANOVA, P < 0.0001).

CONCLUSIONS

VEGF is known to be a regulator of angiogenesis and to simultaneously stimulate elastolytic proteinases. The results of this study suggest that an angiogenic factor, such as VEGF, may play an important role in the degeneration of the aortic wall and could be strongly related to the pathogenesis of IAAA, AAAA, and AOD.

Systemic regulation of distraction osteogenesis: a cascade of biochemical factors

This study investigates the systemic biochemical regulation of fracture healing in distraction osteogenesis compared with rigid osteotomy in a prospective in vivo study in humans. To further clarify the influence of mechanical strain on the regulation of bone formation, bone growth factors (insulin-like growth factor [IGF] I, IGF binding protein [IGFBP] 3, transforming growth factor [TGF] beta1, and basic FGF [bFGF]), bone matrix degrading enzymes (matrix-metalloproteinases [MMPs] 1, 2, and 3), human growth hormone (hGH), and bone formation markers (ALP, bone-specific ALP [BAP], and osteocalcin [OC]) have been analyzed in serum samples from 10 patients in each group pre- and postoperatively. In the distraction group, a significant postoperative increase in MMP-1, bFGF, ALP, and BAP could be observed during the lengthening and the consolidation period when compared with the baseline levels. Osteotomy fracture healing without the traction stimulus failed to induce a corresponding increase in these factors. In addition, comparison of both groups revealed a significantly higher increase in TGF-beta1, IGF-I, IGFBP-3, and hGH in the lengthening group during the distraction period, indicating key regulatory functions in mechanotransduction. The time courses of changes in MMP-1, bone growth factors (TGF-beta1 and bFGF), and hGH, respectively, correlated significantly during the lengthening phase, indicating common regulatory pathways for these factors in distraction osteogenesis. Significant correlation between the osteoblastic marker BAP, TGF-beta1, and bFGF suggests strain-activated osteoblastic cells as a major source of systemically increased bone growth factors during callus distraction. The systemic increase in bFGF and MMP-1 might reflect an increased local stimulation of angiogenesis during distraction osteogenesis.

Retinoscleral control of scleral remodelling in refractive development: a role for endogenous FGF-2?

AIMS

Studies in avian models of myopia have shown that refractive error development can be influenced by exogenously delivered fibroblast growth factor (FGF)-2. The present study sought to determine whether endogenous FGF-2 was associated with retinoscleral signalling or scleral remodelling during changes in refractive error in a mammalian model of myopia.

METHODS

Myopia was induced in tree shrews over a 5-day period. One group of animals was then allowed 3 days of recovery from the induced myopia. Endogenous levels of FGF-2 were measured in scleral and retinal homogenates using ELISA. Real-time PCR was used to investigate scleral FGF-2 and FGF receptor (FGFR)-1 mRNA expression.

RESULTS

No difference in FGF-2 content was found in posterior scleral or retinal extracts of myopic eyes (scleral -4+/-9%, retinal +23+/-17%) or recovering eyes (scleral -10+/-18%, retinal +1+/-13%), when compared with contralateral control eyes. In addition, no significant changes were found in scleral FGF-2 mRNA expression in myopic or recovering eyes (+106+/-56% and +14+/-12% respectively, P=0.21). However, FGF-2 concentration was significantly higher in anterior, relative to posterior, scleral regions in all animals (1602+/-105 vs 1030+/-50pg/mg respectively P<0.001). Expression of scleral FGFR-1 mRNA was upregulated in myopic eyes (+186+/-32%, P=0.01) but returned to control eye levels during recovery (+63+/-20%).

CONCLUSIONS

The findings indicate that alterations in endogenous retinal or scleral FGF-2 levels are not associated with changes in scleral remodelling in this mammalian model of myopia. However, the reversible changes found in FGFR-1 expression in the sclera of myopic eyes mean that an indirect role for FGF-2 in the control of scleral remodelling is implicated. The anteroposterior difference found in scleral FGF-2 concentration indicates a role for this cytokine in the control of normal scleral growth and development and, presumably, eye size.

FGF-2 and TPA induce matrix metalloproteinase-9 secretion in MCF-7 cells through PKC activation of the Ras/ERK pathway

Matrix metalloproteinases (MMPs) play an important role in cancer metastasis. Here, we investigated the effect of fibroblast growth factor-2 (FGF-2) and 12-O-tetradecanoylphorbol-13-acetate (TPA) on the secretion of type IV collagenases (MMP-2, MMP-9) in breast cancer MCF-7 cells. As shown by gelatin zymography, both FGF-2 and TPA stimulated the secretion of MMP-9 in MCF-7 cells while they did not change the level of MMP-2 secretion. Signaling cascade studies indicated that both FGF-2 and TPA induced Ras activation, c-Raf phosphorylation, mitogen-activated protein kinase/ERK kinase (MEK(1/2)) phosphorylation, and extracellular signal-regulated kinase (ERK(1/2)) phosphorylation. The FGF-2- and TPA-induced MMP-9 secretion was significantly inhibited by transient transfection of MCF-7 cells with dominant negative Ras (Ras-N17) and by treatment with MEK(1/2) inhibitor PD98059. A pan-protein kinase C (PKC) inhibitor, GF109203X, was found to totally abolish the FGF-2- and TPA-induced MMP-9 secretion and ERK(1/2) phosphorylation. Use of isoform-specific PKC inhibitors such as Rotllerin and Gö6976 suggested, moreover, that the PKC-delta isoform is a likely component of FGF-2 and TPA trophic signaling. These results demonstrated that FGF-2 and TPA induce MMP-9 secretion in MCF-7 cells mainly through PKC-dependent activation of the Ras/ERK(1/2) signaling pathway.

Matrix metalloproteinase expression in the coronary circulation induced by coronary angioplasty

Recent studies have revealed that matrix metalloproteinases (MMPs) play an important role in cardiovascular remodeling by degrading the extracellular matrix. We investigated changes in the expression of MMPs due to percutaneous transluminal coronary angioplasty (PTCA). We studied 47 patients with ischemic heart disease who underwent elective PTCA on isolated stenotic lesion of left coronary arteries. Twelve patients received conventional balloon angioplasty, 14 percutaneous transluminal rotational atherectomy and 21 stent implantation. Blood samples were drawn from the coronary sinus immediately before and after, as well as 4 and 24 h, after PTCA. Plasma levels of MMP-1, MMP-2, tissue inhibitor of MMP (TIMP)-1 and TIMP-2 were measured by enzyme-linked immunosorbent assay. Plasma MMP-2 activity was determined with the digestion of a specific chromogenic peptide substrate. We could observe serial changes in plasma MMP-1 levels in the coronary circulation only in one patient, because MMP-1 levels were lower than the limit of detection in other patients. On the other hand, plasma MMP-2 levels in the coronary sinus were detectable in all subjects and increased significantly 4 and 24 h after PTCA. Plasma TIMP-1 levels also showed significant increases 4 and 24 h after PTCA, whereas TIMP-2 did not show significant changes. Plasma MMP-2/TIMP-2 ratio and MMP-2 activity in the coronary sinus showed significant increases 4 and 24 h after PTCA. A positive correlation was observed between MMP-2 levels in the coronary sinus 4 h after PTCA and late loss index 6 months after PTCA. MMP-2 levels in the coronary sinus blood were significantly higher in patients with late restenosis than in those without restenosis. PTCA induces increases in plasma MMP-2 levels and activity in the coronary circulation, which may contribute to vascular remodeling and late restenosis after PTCA.

Vascular smooth muscle growth: autocrine growth mechanisms

Vascular smooth muscle cells (VSMC) exhibit several growth responses to agonists that regulate their function including proliferation (hyperplasia with an increase in cell number), hypertrophy (an increase in cell size without change in DNA content), endoreduplication (an increase in DNA content and usually size), and apoptosis. Both autocrine growth mechanisms (in which the individual cell synthesizes and/or secretes a substance that stimulates that same cell type to undergo a growth response) and paracrine growth mechanisms (in which the individual cells responding to the growth factor synthesize and/or secrete a substance that stimulates neighboring cells of another cell type) are important in VSMC growth. In this review I discuss the autocrine and paracrine growth factors important for VSMC growth in culture and in vessels. Four mechanisms by which individual agonists signal are described: direct effects of agonists on their receptors, transactivation of tyrosine kinase-coupled receptors, generation of reactive oxygen species, and induction/secretion of other growth and survival factors. Additional growth effects mediated by changes in cell matrix are discussed. The temporal and spatial coordination of these events are shown to modulate the environment in which other growth factors initiate cell cycle events. Finally, the heterogeneous nature of VSMC developmental origin provides another level of complexity in VSMC growth mechanisms.

Cell surface-bound collagenase-1 and focal substrate degradation stimulate the rear release of motile vascular smooth muscle cells

To migrate in the vessel wall, smooth muscle cells (SMCs) must contend with abundant type I collagen. We investigated the mechanisms used by human SMCs to efficiently migrate on type I collagen, following stimulation with fibroblast growth factor-2 (FGF-2). FGF-2-stimulated migration was inhibited by a hydroxamic acid inhibitor of matrix metalloproteinases and by a neutralizing anti-collagenase-1 antibody. Moreover, migration speed of SMCs plated on mutant collagenase-resistant type I collagen was not increased by FGF-2. Time-lapse video analysis of unstimulated SMCs migrating on collagen revealed discrete phases of leading edge membrane extension and rear retraction, the latter often after rupture of an elongated tail. FGF-2 stimulation yielded a more synchronous, gliding motion with a collagenase-1-mediated decrease in tail ripping. Surface labeling of SMCs with biotin followed by immunoprecipitation revealed that a proportion of active collagenase-1, expressed in response to FGF-2, was bound to the plasma membrane. Pericellular collagen substrate cleavage was verified by immunostaining for neoepitopes generated by collagenase-1 action and was localized to discrete zones beneath the cell tail and the leading edge. These results identify a novel mechanism by which SMC migration on collagen is enhanced, whereby rear release from the substrate is orchestrated by the localized actions of membrane-bound collagenase-1.

The effects of high magnitude cyclic tensile load on cartilage matrix metabolism in cultured chondrocytes

Excessive mechanical load is thought to be responsible for the onset of osteoarthrosis (OA), but the mechanisms of cartilage destruction caused by mechanical loads remain unknown. In this study we applied a high magnitude cyclic tensile load to cultured chondrocytes using a Flexercell strain unit, which produces a change in cell morphology from a polygonal to spindle-like shape, and examined the protein level of cartilage matrixes and the gene expression of matrix metalloproteinases (MMPs), tissue inhibitors of matrix metalloproteinases (TIMPs) and proinflammatory cytokines such as IL-1beta and TNF-alpha. Toluidine blue staining, type II collagen immunostaining, and an assay of the incorporation of [35S]sulfate into proteoglycans revealed a decrease in the level of cartilage-specific matrixes in chondrocyte cultures subjected to high magnitude cyclic tensile load. PCR-Southern blot analysis showed that the high magnitude cyclic tensile load increased the mRNA level of MMP-1, MMP-3, MMP-9, IL-1beta, TNF-alpha and TIMP-1 in the cultured chondrocytes, while the mRNA level of MMP-2 and TIMP-2 was unchanged. Moreover, the induction of MMP-1, MMP-3 and MMP-9 mRNA expression was observed in the presence of cycloheximide, an inhibitor of protein synthesis. These findings suggest that excessive mechanical load directly changes the metabolism of cartilage by reducing the matrix components and causing a quantitative imbalance between MMPs and TIMPs.

Interaction between monocytes and vascular smooth muscle cells enhances matrix metalloproteinase-1 production

Matrix metalloproteinase-1 (MMP-1) plays an important role in atherosclerotic plaque rupture. The purpose of this study was to investigate the expression of MMP-1 by cell-to-cell interactions between monocytes and vascular smooth muscle cells (VSMCs). Human VSMCs and THP-1 cells (human monocytoid cells) were cocultured. MMP-1 levels were measured by enzyme-linked immunosorbent assay. Collagenolytic activity was determined by fluorescent labeled-collagen digestion. Immunohistochemistry was performed to determine which types of cells produce MMP-1. Adding THP-1 cells to VSMCs markedly increased the MMP-1 levels and activity of the culture media. MMP-1 levels were maximal when the cellular ratio of THP-1 cells/VSMCs was 1.0. Immunohistochemistry revealed that both types of cells in the coculture produced MMP-1. Separated coculture experiments showed that both direct contact and a soluble factor(s) contributed to MMP-1 production. Neutralizing anti-interleukin (IL)-6 and tumor necrosis factor-alpha antibodies inhibited coculture conditioned medium-induced MMP-1 production by VSMCs and THP-1 cells. Protein kinase C inhibitors, tyrosine kinase inhibitors, and a mitogen-activated protein kinase inhibitor significantly inhibited MMP-1 production by cocultures. Direct cell-to-cell interaction between THP-1 cells and VSMCs enhanced MMP-1 synthesis in both types of cells. Increased local MMP-1 production and activity induced by monocyte-VSMC interaction play an important pathogenic role in atherosclerotic plaque rupture.

Amlodipine inhibits expression of matrix metalloproteinase-1 and its inhibitor in human vascular endothelial cells

Matrix metalloproteinase-1 (MMP-1) may play an important role in the pathogenesis of atherosclerosis and atherosclerotic plaque rupture. We investigated the effect of the calcium channel blockers amlodipine and nifedipine on the expression of MMP-1 and tissue inhibitor of metalloproteinase-1 (TIMP-1) in endothelial cells (ECs). MMP-1 and TIMP-1 levels in conditioned media of human vascular ECs were measured by enzyme-linked immunosorbent assay. Collagenolytic activity was determined by fluorescence-labeled collagen digestion. The addition of interleukin-1beta (IL-1beta) increased MMP-1 levels in the culture media of ECs. Amlodipine, but not nifedipine, significantly decreased MMP-1 levels in IL-1beta-stimulated ECs. TIMP-1 levels also were significantly increased by IL-1beta, and its expression was slightly decreased by amlodipine, not by nifedipine. Amlodipine significantly inhibited collagenolytic activity in the culture media of IL-1beta-stimulated ECs, whereas nifedipine showed no significant effect on the activity. Our findings revealed that amlodipine, but not nifedipine, inhibits IL-1beta-induced MMP-1 expression in human ECs.

Inverse dose- and time-dependent effect of basic fibroblast growth factor on the gene expression of collagen type I and matrix metalloproteinase-1 by periodontal ligament cells in culture

BACKGROUND

Growth factors are known to play a major role in the regeneration of the periodontium. Basic fibroblast growth factor (bFGF) is a polypeptide growth factor considered to have a role in chemotaxis and mitogenesis of periodontal ligament cells (PLC). The aim of this study was to assess the dose-dependent effect of bFGF administration on the levels of gene expression of collagen type I (a1) (col I), collagen type III (col III), and collagenase-1 (MMP-1) in PLC.

METHODS

PLC were cultured in different concentrations of bFGF (0.1 to 10 ng of bFGF) for 14 and 21 days. At each time point, the gene expression of the examined molecules was assessed semi-quantitatively by reverse transcription-polymerase chain reaction (RT-PCR) assay.

RESULTS

The results indicated that bFGF exhibits an inverse time- and dose-dependent effect on the gene expression of col I and MMP-1: it simultaneously downregulates the gene expression of col I and upregulates the gene expression of MMP-1. On the other hand, bFGF had no dose-dependent effect on col III gene expression. The effect of bFGF on the expression of the three genes was modulated by the time of incubation with bFGF.

CONCLUSIONS

These results suggest that bFGF is one of the important regulators involved in the active remodeling of col I in the periodontal ligament and possibly in other connective tissues.

The role of protein-tyrosine phosphorylation and gelatinase production in the migration and proliferation of smooth muscle cells

BACKGROUND

It has been reported that matrix metalloproteinase (MMP) was expressed in coronary arterial atherosclerotic lesions. However, not much is known about the relationship between the production of MMP and the progression of atherosclerosis.

PURPOSE AND METHOD

To demonstrate the association between the protein-tyrosine phosphorylation (PTP) and the activation of extracellular MMP in the proliferation and migration of vascular smooth muscle cells (VSMCs), the effect of platelet-derived growth factor (PDGF) and vanadate (an inhibitor of protein-tyrosine phosphatase and an activator of certain protein-tyrosine kinases) on mitogenesis ([3H]thymidine incorporation after 24 hours), migration, PTP (Western blot analysis using anti-phosphotyrosine antibodies), and production of MMP (gelatin zymography) was examined in cultured VSMCs.

RESULTS

Both vanadate (1-5 micromol/l) and PDGF (1-10 ng/ml) caused a dose-dependent increase in thymidine incorporation and migration and produced 72-kDa type IV gelatinase (MMP-2) in VSMCs. The combination of vanadate and PDGF resulted in a dose-dependent synergistic effect on thymidine incorporation and MMP-2 production. Western blot analysis revealed that PDGF caused an increase in PTP, extracellular signal-regulated kinases (ERK1, ERK2) and PDGF receptor in VSMCs. Vanadate given together with PDGF induced a marked increase in the intensity of tyrosine phosphorylation in these proteins. Tyrosine kinase inhibitors (genistein and herbimycin A) and a synthetic inhibitor of MMP (1,10-phenanthroline) and an anti-MMP-2 neutralizing antibody inhibited the mitogenic effect induced by vanadate and/or PDGF.

CONCLUSIONS

The data suggest that the proliferation and migration of cultured VSMCs was closely related to the stimulation of MMP-2 production that was induced through activation of PTK.

Enhanced embryonic nonmuscle myosin heavy chain isoform and matrix metalloproteinase expression in aortic abdominal aneurysm with rapid progression

Abdominal aortic aneurysms (AAAs) are characterized by structural deterioration of aortic wall leading to progressive dilatation. The histopathological changes in AAAs are particularly evident within the elastic media, which is normally comprised mainly of vascular smooth muscle cells (SMCs). There are vascular myosin heavy chain (MHC) isoforms; SM2 is specifically expressed in differentiated SMCs and SMemb is a nonmuscle-type MHC abundantly expressed in SMCs of the fetal aorta with an immature phenotype. Although AAA altered expression of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs), pathophysiological role of SMC phenotypic modulation in the AAA progression remains uncertain. To determine whether phenotypic modulation in vascular SMCs contributes to arterial medial degeneration, we examined MHC expression in SMCs of AAA. Aortic specimens were obtained from patients with slowly progressed AAA (n = 12) and rapidly progressed AAA (n = 5), and compared with normal aortic tissue (n = 3). Immunohistochemical staining was performed for detection of SMemb, SM2, MMP (types 2 and 9) and TIMP (types 1 and 2). Faint SMemb and abundant SM2 were observed in normal aorta, while the balance shifted to SMemb predominance in AAAs. Compared with slowly progressed AAA tissue, rapidly expanded AAA tissue demonstrated marked increases in SMemb expression with suppressed SM2. Predominant SMemb expression indicates presence of phenotypic modulated SMCs and enhanced MMP; while abundant TIMP was seen in mature SMCs expressing SM2. SMemb expression is markedly increased in AAA with MMP enhancement, and a significant imbalance between SMemb and SM2 results in rapid progression of AAA.

Collagens and atherosclerosis

Smooth muscle cells in the atherosclerotic lesions of diseased arteries produce new extracellular matrix, largely collagenous in nature, which is responsible in part for the occlusion of the vessel lumen by the atherosclerotic plaque. These smooth muscle cells express a different phenotype, responsive to growth factors, to that of the differentiated, nondividing contractile cell in the media. Specific collagens may be involved in the regulation of phenotype and in the migration of the cells to the site of lesion growth. Collagens may also be involved in the calcification of lesions, in the retention of low-density lipoprotein in the vessel wall and in smooth muscle cell survival. Glycation of collagen may promote atherogenesis. Effects as summarized in this short review, are not always, at first sight, consistent. The following points should be kept in mind, though, when considering the response of a cell to collagen. Any effect may be governed not just by the identity of the collagen type as such but by its state of polymerization: monomeric collagen, for instance, whether in solution or immobilized on plastic, may express different effects to the same collagen type when presented in its native polymerized state, e.g., as fibers. The precise identity of the cell and its location may be important: SMCs in secondary culture may not necessarily respond to any given collagen exactly as SMCs within the lesion or possess precisely the same properties, albeit both types are regarded as expressing the same (synthetic) phenotype. Effects may not necessarily be directly attributable to collagen, but to some other matrix constituent bound to collagen.

Acidic fibroblast growth factor induces an antifibrogenic phenotype in human lung fibroblasts

Acidic fibroblast growth factor (FGF-1), a prototype member of the heparin-binding growth factor family, influences proliferation, differentiation, and protein synthesis in different cell types. However, its possible role on lung extracellular matrix (ECM) metabolism has not been evaluated. In this study we examined the effects of FGF-1 and FGF-1 plus heparin on type I collagen, collagen-binding stress protein HSP47, interstitial collagenase (matrix metalloproteinase [MMP]-1), gelatinase A, and tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 expression by normal human lung fibroblasts. Heparin was used because it enhances the biologic activities of FGF-1. Fibroblasts were exposed either to 20 ng/ml FGF-1 plus 100 micrograms/ml heparin for 48 h or to FGF-1 or heparin alone. Messenger RNA (mRNA) expression was analyzed by Northern blot. Collagen synthesis was evaluated by digestion of [3H]collagen with bacterial collagenase, MMP-1 by Western blot, and gelatinolytic activities by zymography. Our results show that FGF-1 induced collagenase mRNA expression, which was strongly enhanced when FGF-1 was used with heparin. Likewise, both FGF-1 and FGF-1 plus heparin reduced by 70 to 80% the expression of type I collagen transcript, in part through effect on pro-alpha1(I) collagen mRNA stability. A downregulation of HSP47 gene expression was also observed. Synthesis of collagen and collagenase proteins paralleled gene expression results. FGF-1 activities were abolished with genistein, a tyrosine kinase inhibitor. Neither FGF-1 nor FGF-1 plus heparin affected the expression of TIMP-1, TIMP-2, and gelatinase A. These findings demonstrate that FGF-1, mostly in the presence of heparin, upregulates collagenase and downregulates type I collagen expression that might have a protective role in avoiding collagen accumulation during lung ECM remodeling.

Tissue inhibitors of metalloproteinases and metalloproteinases in atherosclerosis

The ability of the metalloproteinases to degrade extracellular matrix proteins is essential for the matrix remodelling that occurs during infiltration of inflammatory cells, intimal thickening, angiogenesis and plaque rupture which are a result of atherosclerosis. Increased metalloproteinase activity therefore requires stimulation of metalloproteinase expression by cytokines and growth factors, activation of metalloproteinases, and downregulation of tissue inhibitors of metalloproteinases. In addition, metalloproteinases may influence atherosclerosis by processing of proteins involved in inflammation and cell growth and death and the tissue inhibitors of metalloproteinases may also play a less inhibitory role by influencing cell growth and apoptosis.