Effects of high glucose and thiamine on the balance between matrix metalloproteinases and their tissue inhibitors in vascular cells

Pericyte survival in diabetic retinopathy depends also on interactions with extracellular matrix (ECM) proteins, which are degraded by matrix metalloproteinases (MMP). Elevated glucose influences ECM turnover, through expression of MMP and their tissue inhibitors, TIMP. We reported on reduced pericyte adhesion to high glucose-conditioned ECM and correction by thiamine. We aimed at verifying the effects of thiamine and benfotiamine on MMP-2, MMP-9 and TIMP expression and activity in human vascular cells with high glucose. In HRP, MMP-2 activity, though not expression, increased with high glucose and decreased with thiamine and benfotiamine; TIMP-1 expression increased with high glucose plus thiamine and benfotiamine; MMP-9 was not expressed. In EC, MMP-9 and MMP-2 expression and activity increased with high glucose, but thiamine and benfotiamine had no effects; TIMP-1 expression was unchanged. Neither glucose nor thiamine modified TIMP-2 and TIMP-3 expression. TIMP-1 concentrations did not change in either HRP or EC. High glucose imbalances MMP/TIMP regulation, leading to increased ECM turnover. Thiamine and benfotiamine correct the increase in MMP-2 activity due to high glucose in HRP, while increasing TIMP-1.

Interleukin-1alpha treatment of meniscal explants stimulates the production and release of aggrecanase-generated, GAG-substituted aggrecan products and also the release of pre-formed, aggrecanase-generated G1 and m-calpain-generated G1-G2

Pro-inflammatory cytokines induce meniscal matrix degradation and inhibition of endogenous repair mechanisms, but the pathogenic mechanisms behind this are mostly unknown. Therefore, we investigated details of interleukin-1 (IL-1alpha)-induced aggrecan turnover in mature meniscal tissue explants. Fibro-cartilagenous disks (3 mm diameter x 1 mm thickness) were isolated from the central, weight-bearing region of menisci from 2-year-old cattle. After 3 or 6 days of IL-1alpha-treatment, GAG loss (DMMB assay), biosynthetic activity ([(35)SO(4)]-sulfate and [(3)H]-proline incorporation), gene expression (quantitative RT-PCR) and the abundance (zymography, Western blot) of matrix-degrading enzymes and specific aggrecan products were determined. Meniscal fibrocartilage had a 4-fold lower GAG content (per wet weight) than adjacent articular cartilage, and expressed MMPs-1, -2, -3 and ADAMTS4 constitutively, whereas ADAMTS5 m-RNA was essentially undetectable. Significant IL-1 effects were a decrease in biosynthetic activity, an increase in GAG release and in the expression/abundance of MMP-2, MMP-3 and ADAMTS4. Fresh tissue contained aggrecan core protein products similar to those previously described for bovine articular cartilage of this age. IL-1 induced the release of aggrecanase-generated CS-substituted products including both high (>250 kDa) and low molecular weight (about 75 kDa) species. TIMP-3 (but not TIMP-1 and -2 or a broad spectrum MMP inhibitor) inhibited IL-1-dependent GAG loss. In addition, IL-1 induced the release of preformed pools of three known G1-bearing products. We conclude that aggrecanases are responsible for IL-1-stimulated GAG release from meniscal explants, and that IL-1 also stimulates release of G1-bearing products, by a process possibly involving hyaluronan fragmentation.

Human rheumatoid arthritis tissue production of IL-17A drives matrix and cartilage degradation: synergy with tumour necrosis factor-alpha, Oncostatin M and response to biologic therapies

INTRODUCTION

The aim of this study was to examine IL-17A in patients, following anti-TNF-alpha therapy and the effect of IL-17A on matrix turnover and cartilage degradation.

METHODS

IL-17A expression was examined by ELISA and immunohistology in the rheumatoid arthritis (RA) joints. RA whole synovial tissue explant (RA ST), primary synovial fibroblasts (RASFC), human cartilage and chondrocyte cultures were stimulated with IL-17A +/- TNF-alpha and Oncostatin M (OSM). Matrix metalloproteinase (MMP) and tissue inhibitor (TIMP-1) were assessed by ELISA and zymography. Cartilage proteoglycan release was assessed histologically by Safranin-O staining. Clinical parameters, IL-17A, MMP/TIMP were assessed in patients pre/post biologic therapy.

RESULTS

IL-17A levels were higher in RA vs osteoarthritis (OA)/normal joints (P < 0.05). IL-17A up-regulated MMP-1, -2, -9, and -13 in RA ST, RASFC, cartilage and chondrocyte cultures (P < 0.05). In combination with TNF-alpha and OSM, IL-17A shifted the MMP:TIMP-1 ratio in favor of matrix degradation (all P < 0.05). Cartilage proteoglycan depletion in response to IL-17A was mild; however, in combination with TNF-alpha or OSM showed almost complete proteoglycan depletion. Serum IL-17A was detected in 28% of patients commencing biologic therapy. IL-17A negative patients demonstrated reductions post therapy in serum MMP1/TIMP4, MMP3/TIMP1 and MMP3/TIMP4 ratios and an increase in CS846 (all P < 0.05). No significant changes were observed in IL-17A positive patients.

CONCLUSIONS

IL-17A is produced locally in the inflamed RA joint. IL-17A promotes matrix turnover and cartilage destruction, especially in the presence of other cytokines, mimicking the joint environment. IL-17A levels are modulated in vivo, following anti-TNF therapy, and may reflect changes in matrix turnover.

Inhibition of histone deacetylases antagonized FGF2 and IL-1beta effects on MMP expression in human articular chondrocytes

Fibroblast growth factor-2 (FGF2) and interleukin-1beta (IL-1beta) stimulate the expression of matrix metalloproteinases (MMPs) in articular chondrocytes, which may contribute to cartilage degradation and development of osteoarthritis. Histone deacetylases (HDACs) have recently been implicated in the regulation of MMP gene expression. To investigate the functional involvement of HDACs in the signaling pathway of FGF2 and IL-1beta, we examined the effects of HDAC inhibition on activities of FGF2 or IL-1beta on gene expression of MMP-1, MMP-3, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS5), collagen type II, and aggrecan. Human articular chondrocyte cultures were treated with FGF2 or IL-1beta in the presence or absence of HDAC inhibitor (trichostatin A, TSA). Gene expression levels after treatments were assessed using quantitative real time PCR. Results showed that FGF2 and IL-1beta both increased MMP-1 and -13 expression, while IL-1beta also increased MMP-3 mRNA levels. These effects were attenuated in the presence of TSA in a dose dependent manner. In contrast to the effects on MMPs, FGF2 decreased mRNA levels of ADAMTS-5, which was not affected by HDAC inhibition. FGF2, IL-1beta, and TSA inhibited expression of aggrecan, while TSA also decreased mRNA levels of collagen type II. These findings showed that HDAC inhibition antagonized FGF2 and IL-1beta induced MMP expression. Combination of FGF2 and the HDAC inhibitor decreases both anabolic and catabolic genes, which may slow the cartilage turnover and be beneficial for maintaining cartilage integrity.

Inhibition of TGF-beta1 suppresses motility and invasiveness of oral squamous cell carcinoma cell lines via modulation of integrins and down-regulation of matrix-metalloproteinases

Transforming growth factor (TGF)-beta1 is a multifunctional polypeptide that regulates a variety of cellular processes. Several studies have indicated that it is associated with epithelial-mesenchymal transition, angiogenesis, migration and metastases in many types of malignant tumors. We have used a wound-healing assay and a Matrigel invasion assay to evaluate the effects of TGF-beta1 and TGF-beta receptor I kinase inhibitor (TRI) on the cell motility and invasiveness of the human oral squamous cell carcinoma (OSCC) cell lines SAS-L1 and HSC-3. While TGF-beta1 enhanced the migration and invasion of OSCC cells, TRI significantly suppressed the migration and invasion of these cells. Exogenous TGF-beta1 up-regulated the activity of type IV collagenase (gelatinase A and gelatinase B), whereas TRI down-regulated the activity of these matrix metalloproteinases. Western blot analysis revealed that TGF-beta1 enhanced the expression of alpha5, alphav, beta1, beta6 and alphavbeta3 integrin subunits, and these enhanced integrins were down-regulated by treatment with TRI. These results suggest that the inhibition of TGF-beta1 suppresses motility and invasiveness of OSCC cells via modulation of integrins and matrix-metalloproteinases. Therefore, targeting the TGF-beta1 signaling pathway could be beneficial in the treatment of patients with OSCC.

Inhibition effect of Guizhi-Fuling-decoction on the invasion of human cervical cancer

AIM OF THE STUDY

Guizhi-Fuling-decoction (GZFLD), a traditional Chinese medical formulation, exerts an anti-tumor effect, but the mechanisms of its action on invasive tumor inhibition have not been documented. The aims of this study were to identify the inhibitory effect of GZFLD on the invasive of cervical cancer and to elucidate the extensional mechanisms of its action.

MATERIALS AND METHOD

The invasive ability of HeLa cells was tested with Transwell chamber. The expressions and activities of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) were measured by zymography/reverse zymography, RT-PCR and Western blot analysis. Establish tumor-bearing mice model to assess the ability of GZFLD to inhibit tumor growth and angiopoiesis in vivo.

RESULTS

We have found that GZFLD suppressed the invasive ability of HeLa cells, inhibited MMPs expressions and activities, increased TIMPs expressions and activities, and furthermore restored the MMPs-TIMPs balance in HeLa cells in a concentration-dependent manner. Meanwhile in vivo, GZFLD had significantly inhibited tumor growth and angiopoiesis.

CONCLUSION

In general, our results showed that GZFLD had inhibited the invasion of cervical cancer both in vitro and vivo. The inhibitory effects may be associated with restoring the MMPs-TIMPs balance, and then suppressing the degradation of extracellular matrix.

The plasminogen fibrinolytic pathway is required for hematopoietic regeneration

Hematopoietic stem cells within the bone marrow exist in a quiescent state. They can differentiate and proliferate in response to hematopoietic stress (e.g., myelosuppression), thereby ensuring a well-regulated supply of mature and immature hematopoietic cells within the circulation. However, little is known about how this stress response is coordinated. Here, we show that plasminogen (Plg), a classical fibrinolytic factor, is a key player in controlling this stress response. Deletion of Plg in mice prevented hematopoietic stem cells from entering the cell cycle and undergoing multilineage differentiation after myelosuppression, leading to the death of the mice. Activation of Plg by administration of tissue-type plasminogen activator promoted matrix metalloproteinase-mediated release of Kit ligand from stromal cells, thereby promoting hematopoietic progenitor cell proliferation and differentiation. Thus, activation of the fibrinolytic cascade is a critical step in regulating the hematopoietic stress response.

CPU0213, a novel endothelin receptor antagonist, suppresses the upregulation of matrix metalloproteinases and connexin 43 in hyperthyroid myocardium

It has been verified that endothelin-1 (ET-1) activates matrix metalloproteinase (MMP) in the process of myocardial remodeling. Sustained high thyroid hormone level gives rise to left ventricular hypertrophy, in which the ET-1 system is probably involved.We attempted to study the effects of CPU0213, a novel endothelin receptor antagonist, on myocardial remodeling induced by high dose L-thyroxin. Adult male Sprague-Dawley rats were treated with L-thyroxin (0.4 mg/kg/d, sc) for 10 days to induce left ventricular hypertrophy. Asubset of rats was given CPU0213 from day 6 to 10. Alterations in MMP, tissue inhibitor of metalloproteinase (TIMP), and connexin 43 were measured by reverse transcription polymerase chain reaction (RT-PCR), zymography, and Western blot assays. L-thyroxin treatment resulted in increased mRNA expression and MMP-2 and MMP-9 activities, along with decreased TIMP-1 and TIMP-2 mRNA expression. CPU0213 suppressed the increased activity of MMP, and prevented the downregulation of TIMP expression. The expression of connexin 43 was upregulated at both mRNAand protein levels after L-thyroxin treatment, which was attenuated by CPU0213. In addition, L-thyroxin caused upregulation of mRNA expression of preproET-1 (ppET-1) and endothelin converting enzyme (ECE). These results suggest that the ET receptors mediate high dose L-thyroxin induced myocardial remodeling by changing MMP, TIMP activities and connexin 43.

Effect of photodynamic therapy on the extracellular matrix and associated components

In many countries, photodynamic therapy (PDT) has been recognized as a standard treatment for malignant conditions (for example, esophageal and lung cancers) and non-malignant ones such as age-related macular degeneration and actinic keratoses. The administration of a non-toxic photosensitizer, its selective retention in highly proliferating cells and the later activation of this molecule by light to form reactive oxygen species that cause cell death is the principle of PDT. Three important mechanisms are responsible for the PDT effectiveness: a) direct tumor cell kill; b) damage of the tumor vasculature; c) post-treatment immunological response associated with the leukocyte stimulation and release of many inflammatory mediators like cytokines, growth factors, components of the complement system, acute phase proteins, and other immunoregulators. Due to the potential applications of this therapy, many studies have been reported regarding the effect of the treatment on cell survival/death, cell proliferation, matrix assembly, proteases and inhibitors, among others. Studies have demonstrated that PDT alters the extracellular matrix profoundly. For example, PDT induces collagen matrix changes, including cross-linking. The extracellular matrix is vital for tissue organization in multicellular organisms. In cooperation with growth factors and cytokines, it provides cells with key signals in a variety of physiological and pathological processes, for example, adhesion/migration and cell proliferation/differentiation/death. Thus, the focus of the present paper is related to the effects of PDT observed on the extracellular matrix and on the molecules associated with it, such as, adhesion molecules, matrix metalloproteinases, growth factors, and immunological mediators.

In vivo effects of insulin and free fatty acids on matrix metalloproteinases in rat aorta

OBJECTIVE

Obesity is associated with insulin resistance, hyperinsulinemia, elevated plasma free fatty acid (FFA), and increased risk for atherosclerotic vascular disease (ASVD). A part of this increased risk may be due to enhanced activation of matrix metalloproteinases (MMPs). Here, we have examined the effects of physiologically elevated levels of insulin and FFA on three MMPs and their inhibitors (tissue inhibitors of MMP [TIMPs]) in aortic tissue of male rats during euglycemic-hyperinsulinemic clamping.

RESEARCH DESIGN AND METHODS

Four-hour euglycemic-hyperinsulinemic clamps with infusion of saline/glycerol, lipid/heparin, or insulin with or without lipid/heparin were performed in alert unrestrained male rats.

RESULTS

Hyperinsulinemia increased MMP-2 ( approximately 6-fold), MMP-9 ( approximately 13-fold), membrane type 1-MMP (MT1-MMP; approximately 8-fold) (all Western blots), and gelatinolytic activity (zymography) of MMP-2 (2-fold), while not affecting TIMP-1 and TIMP-2. Insulin increased IRS-1-associated PI 3-kinase (PI3K), extracellular signal-regulated kinases 1/2 (ERK1/2), and c-jun NH(2)-terminal kinase (JNK) (by Western blots with phospho-specific antibodies). FFA augmented the insulin-mediated increases in MMP-2 (from approximately 6- to approximately 11-fold), MMP-9 (from approximately 3- to approximately 23-fold), MT1-MMP (from approximately 8- to approximately 20-fold), MMP-2 gelatinolytic activity (from 2- to 3-fold), and JNK and p38 mitogen-activated protein kinase (MAPK) activities but decreased insulin-mediated activation of PI3K and ERK1/2. Raising FFA without raising insulin affected neither MMPs nor TIMPs.

CONCLUSIONS

FFA augmented insulin stimulation of the MMP/TIMP balance of three proatherogenic MMPs and increased activities of two MAPKs (JNK and p38 MAPK), both of which are known to stimulate the production of proinflammatory cytokines. This may, over time, increase degradation of extracellular matrix and together with inflammatory changes promote development of ASVD.

The impact of aryl hydrocarbon receptor signaling on matrix metabolism: implications for development and disease

The aryl hydrocarbon receptor (AhR) was identified as the receptor for polycyclic aromatic hydrocarbons and related compounds. However, novel data indicate that the AhR binds a variety of unrelated endogenous and exogenous compounds. Although AhR knockout mice demonstrate that this receptor has a role in normal development and physiology, the function of this receptor is still unclear. Recent evidence suggests that AhR signaling also alters the expression of genes involved in matrix metabolism, specifically the matrix metalloproteinases (MMPs). MMP expression and activity is critical to normal physiological processes that require tissue remodeling, as well as in mediating the progression of a variety of diseases. MMPs not only degrade structural proteins, but are also important mediators of cell signaling near or at the cell membrane through exposure of cryptic sites, release of growth factors, and cleavage of receptors. Therefore, AhR modulation of MMP expression and activity may be critical, not only in pathogenesis, but also in understanding the endogenous function of the AhR. In this review we will examine the data indicating a role for the AhR-signaling pathway in the regulation of matrix remodeling, and discuss potential molecular mechanisms.

Influence of retinoids on skin fibroblasts metabolism in vitro

The most dangerous environmental factor for our skin condition is ultraviolet light radiation. Chronic exposition to ultraviolet light can induce epidermal atrophy, keratosis, depigmentation and dysplasia. In the dermis, UV light causes dramatic up-regulation of extracellular matrix-degrading enzymes. Matrix metalloproteinases (MMPs) are engaged in collagen, elastin and other extracellular matrix components degradation. In addition, to increase level of destructive enzymes, UV light has been shown to decrease collagen production. As a consequence of UV impact on skin, it shows signs of aging including loss of tone and elasticity, increased skin fragility, blood vessels weakness and wrinkles. The most dangerous effect of UV on skin is an increased risk of melanoma and other skin cancers. Retinoids are well known antiaging agents. For many years this vitamin has been used for the prevention and treatment of photoaging. Retinoids abolish cellular atypia, increase compacting of the stratum corneum and reduce skin hyperpigmentation caused by sun light. Recent evidence suggests that retinoids also play a role in the prevention of aging, because of its inhibitory effects on metalloproteinases expression. The aim of this study was to examine if all-trans-retinoic acid (ATRA) effects MMP-1, MMP-2, MMP-3 and MMP-14 gene expression in fibroblasts cultured in vitro.

Evidence for species differences in the regulation of MMPs by all-trans retinoic acid in cytokine-stimulated chondrocytes

In inflammatory conditions, chondrocytes produce large amounts of matrix metalloproteases (MMP) and nitric oxide (NO) thought to contribute to joint degradation. We tested the ability of all-trans retinoic acid (ATRA, a retinoic acid receptor (RAR) agonist) to modulate these inflammatory genes in chondrocytes from humans or rats, chosen as representative of animal models of arthritis. All RAR subtypes and RXR-alpha or -beta were expressed at the mRNA level in both species, although IL-1beta (10 ng/ml) inhibited RAR subtypes more markedly in rat than in human cells. ATRA (300 or 1000 nM) inhibited IL-1-induced expression of iNOS and nitrites level in both species, although the NO pathway was induced maximally in rat cells. ATRA displayed controversial effects on MMPs between rat and human chondrocytes, especially for MMP-9 expression. The effects of ATRA were irrelevant to the nuclear translocation of AP-1. The present data underlines that retinoids have a species-dependent impact on IL-1-induced responses in chondrocytes, suggesting that extrapolation of their pharmacological properties from animal cells has a poor relevance to clinical situation.

A bioactively modified fatty acid improves survival and impairs metastasis in preclinical models of acute leukemia

PURPOSE

Polyunsaturated fatty acids (PUFA) and the sulfur-substituted fatty acid tetradecylthioacetic acid (TTA) inhibit proliferation and induce apoptosis in lymphoma and leukemic cell lines, but it is unknown if they can modify leukemogenesis in the intact organism.

EXPERIMENTAL DESIGN

We now examined the effects of PUFA and TTA in rats transplanted with either acute promyelocytic leukemia or acute T-cell leukemia. The rats were randomized to isoenergetic diets containing either lard (control), omega3 (n-3) PUFA, or TTA.

RESULTS

Whereas TTA prolonged survival (P < 0.05) in both types of rat leukemia, n-3 PUFA had no significant effect compared with controls. Only TTA inhibited (P < 0.05) leukemic infiltration in the bone marrow and spleen, probably due to apoptosis of the leukemic cells. Plasma metalloproteinase activity, a marker of metastatic activity, was significantly reduced in TTA-fed rats only.

CONCLUSIONS

Dietary intake of TTA, but not of n-3 PUFA, in rats with acute leukemia, prolonged their survival. TTA intake was also associated with reduced leukemic cell burden as well as diminished extramedullar dissemination. TTA represents a modified fatty acid that exerts unique effects on malignant hematopoietic cells, and the present study indicates that TTA may have a therapeutic potential in patients with acute leukemias.

Serum levels of sex steroid hormones and matrix metalloproteinases after intra-articular glucocorticoid treatment in female patients with rheumatoid arthritis

OBJECTIVES

To study metalloproteinase activity and sex steroid hormone production in serum after intra-articular glucocorticoid treatment for knee synovitis.

METHODS

18 female patients with rheumatoid arthritis and synovitis of the knee with need for intra-articular glucocorticoid treatment were included in this study. Serum samples of matrix metalloproteinases (MMP-1/TIMP complex and MMP-3), dehydroepiandrosterone sulphate, testosterone, oestradiol, steroid hormone binding globulin, follicle stimulating hormone and luteinising hormone were collected before injection with 20 mg triamcinolone hexacetonide, and 24 h, 48 h, 1 week and 2 weeks after injection, respectively.

RESULTS

Serum levels of MMP-3 were significantly decreased, but MMP-1/TIMP complex was unaffected. Dehydroepiandrosterone sulphate, testosterone and oestradiol levels all decreased and tended to return to baseline levels during the observation period. Steroid hormone binding globulin, follicle stimulating hormone and luteinising hormone levels were unchanged.

CONCLUSIONS

Intra-articular glucocorticoid treatment causes a temporary, but considerable suppression of sex steroid hormone secretion. The reduction of MMP-3 indicates an inhibition of the inflammatory, but probably also the cartilage destructive processes within the treated joint.

Leukotriene D4 enhances the function of endothelin-1-primed fibroblasts

Airway inflammation is accompanied by structural changes, termed remodeling, that lead to lung dysfunction over the long term. Although both endothelin-1 (ET-1) and cysteinyl leukotrienes (CysLTs) appear to be involved in airway remodeling in several lung diseases, how these molecules interact remains largely unknown. In this study, we examined the effects of leukotriene (LT) D(4) on the function of ET-1-primed fibroblasts. ET-1 at 10(-7) M up-regulated the expression of the CysLT receptors at both the mRNA and protein levels in human lung fibroblasts. LTD(4) enhanced matrix metalloproteinase-2 and pro-collagen production, and alpha-smooth muscle actin expression of ET-1-primed fibroblasts, but had little or no effect on unprimed fibroblasts. The CysLT1 receptor antagonist montelukast completely abrogated the effects of LTD(4). Our data suggested that LTD(4) may act as a precipitating factor during ET-1-mediated airway remodeling and that CysLT1 receptor antagonists may have a role in preventing aberrant extracellular matrix degradation.

Protective effect of Liuwei Dihuang decoction on early diabetic nephropathy induced by streptozotocin via modulating ET-ROS axis and matrix metalloproteinase activity in rats RETRACTED ARTICLE

We aimed to investigate the effects of Liuwei Dihuang decoction (LW) on the endothelin-1-reactive oxidative species (ET-ROS) system and matrix metalloproteinases (MMPs) in the early diabetic nephropathy induced by streptozotocin (STZ) in rats. Rats were divided into six groups as follows: the control group, the untreated model group, the treated groups with the LW (5, 10 and 15 g kg(-1), p.o.) and the aminoguanidine-treated group (100 mg kg(-1), orally). The treatment was performed for 4 weeks, beginning on the fifth week after one intraperitoneal injection of STZ (65 mg kg(-1)). In the untreated model group, increased blood glucose, decreased plasma insulin level and an impaired renal function were observed. There was an altered redox system shown by an increased malondialdehyde and decreased activity of glutathione peroxidase and superoxide dismutase in the renal cortex. An enhanced inducible nitric oxide synthetase, total nitric oxide synthase and constitutive nitric oxide synthase and a declined nitric oxide were found. An increased extracellular matrix was indicated by an abnormality of MMP-2 and MMP-9 activities and an increase in hydroxyproline. An up-regulated ET-1 level and increased mRNA expression of endothelin-converting enzyme, preproET-1 and ET( A) receptor were presented in the affected renal cortex, but no change in ET(B) receptor mRNA. The LW was most effective in reversing these changes in diabetic rats and was as effective as aminoguanidine. The benefits of the extracts in relieving the abnormalities in early diabetic nephropathy are likely to be mediated by suppression of the renal ET-ROS system and escalating the activity of MMPs.

Analysis of biologic surrogate markers from a Children's Oncology Group Phase I trial of gefitinib in pediatric patients with solid tumors

This trial evaluated the effect of gefitinib on the plasma circulating levels of epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMP)-2 and -9 of patients treated on a pediatric Phase I trial. Complete plasma correlative studies were obtained from 16 of the 25 enrolled patients. There was a trend for lower MMP-2 baseline levels in patients with partial response or stable disease. The Ewing sarcoma from the only patient with partial response lacked egfr mutations. Gefitinib did not induce any significant variation in the levels of the assessed parameters, and none of these determinations showed significant predictive or prognostic value.

Effect of angiotensin II on primary cardiac fibroblast matrix metalloproteinase activities

Left ventricular dysfunction is associated with reperfusion injury occurring during open-heart surgery. There is an increased secretion of angiotensin II (Ang II) and increased matrix metalloproteinases (MMPs) activities associated with open-heart surgery that may affect the cardiac extracellular matrix (ECM). The goal of this study was to determine the effects of Ang II and selective angiotensin II receptor (AT1-R and AT2-R) blockers on the enzymatic activities of MMPs in primary adult murine cardiac fibroblasts (CF). Our hypothesis is that Aug II, with and without a selective receptor blocker, differentially affects CF MMPs activities. The CF were treated with Ang II (10(-6) M) and doses of AT1-R and AT2-R blockers (losartan and PD123319, respectively) at doses of 10(-7) to 10(-5) M for 48 hours. The Ang II-stimulated CF reduced collagenase activities by only 24% (p = 0.004); however, the MMP-2 and MMP-9 gelatinase activities were reduced by 42% and 39%, respectively (p = 0.022). The losartan dose dependently increased MMP-2 (p = 0.02) and MMP-9 (ns). PD123319 at 10(-5) M significantly reduced MMP-2 and MMP-9 activities compared with the Ang II group (p = 0.014 and p = 0.02, respectively). The doses of PD123319 at 10(-6) and 10(-7) M increased the MMP-2 and MMP-9 enzymatic activities significantly above the Ang II only group. Thus, Ang II and AT1-R and AT2-R differentially affect the collagenase and gelatinase MMPs activities released by cardiac fibroblasts.

Nicotine increases the collagen-degrading ability of human gingival fibroblasts

BACKGROUND AND OBJECTIVE

The objective of this study was to determine the effects that nicotine and the combination of nicotine and Porphyromonas gingivalis supernatant have on human gingival fibroblast-mediated collagen degradation.

MATERIAL AND METHODS

Human gingival fibroblasts were cultured with 25-500 microg/ml of nicotine in collagen-coated six-well plates. On days 1-5, the conditioned media was collected for zymography and western blot analyses of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). The cells were then removed and the collagen cleavage visualized by Coomassie blue staining. To examine the combined effect, 250 microg/ml of nicotine and 10% v/v culture supernatant of P. gingivalis ATCC 33277 were added to the human gingival fibroblasts. The mRNA levels of multiple MMPs and TIMPs were monitored.

RESULTS

Nicotine increased the human gingival fibroblast-mediated collagen cleavage. The MMP-14 and MMP-2 produced by the nicotine-treated human gingival fibroblasts more readily underwent zymogen activation. Nicotine treatment resulted in TIMP-2 redistribution to the cell surface. The mRNAs of multiple MMPs and TIMPs were unaltered by nicotine. An additive collagen cleavage effect was observed when the human gingival fibroblasts were treated with both nicotine and P. gingivalis.

CONCLUSION

Nicotine increased human gingival fibroblast-mediated collagen degradation, in part through the activation of membrane-associated MMPs. Nicotine and P. gingivalis had an additive effect on human gingival fibroblast-mediated collagen degradation.

Matrix metalloproteases: underutilized targets for drug delivery

Pathophysiological molecules in the extracellular environment offer excellent targets that can be exploited for designing drug targeting systems. Matrix metalloproteases (MMPs) are a family of extracellular proteolytic enzymes that are characterized by their overexpression or overactivity in several pathologies. Over the last two decades, the MMP literature reveals heightened interest in the research involving MMP biology, pathology and targeting. This review describes various strategies that have been designed to utilize MMPs for targeting therapeutic entities. Key factors that need to be considered in the successful design of such systems have been identified based on the analyses of these strategies. Development of targeted drug delivery using MMPs has been steadily pursued; however, drug delivery efforts using these targets need to be intensified and focused to realize the clinical application of the fast developing fundamental MMP research.

In vitro effects of non-steroidal anti-inflammatory drugs on cytokine, prostanoid and matrix metalloproteinase production by interface membranes from loose hip or knee endoprostheses

OBJECTIVE

To study the effects of the non-steroidal anti-inflammatory drugs (NSAIDs) aceclofenac, piroxicam, tenoxicam and indomethacin on cytokine, matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs) and prostaglandin E2 (PGE2) production, by interface membranes (IFT), obtained at revision surgery for aseptic loosening of total joint arthroplasty. Involvement of these soluble factors is well documented and probably, a pharmaceutically induced inhibition of them might retard loosening.

METHODS

IFTs from 10 patients with a loose hip or knee endoprosthesis were collected. The possibility of septic loosening was thoroughly excluded by histopathologic and microbiologic evaluation. IFTs were cultured in the absence or presence of the tested drugs and the levels of the soluble mediators were determined, using electrophoretic and enzyme-linked immunosorbent assay techniques. Paracetamol was used as neutral drug.

RESULTS

All NSAIDs exhibited a pronounced inhibitory effect upon the production of interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha). This specific effect on IL-6 is reported in the literature for the first time. The majority of NSAIDs also induced the production of IL-1beta in an adequate portion of samples. These drugs did not have a clear effect on MMP synthesis, but they had a stimulatory tendency on TIMP-1 production. Paracetamol, significantly decreased the synthesis of TNF-alpha and that of the gelatinases.

CONCLUSION

Our in vitro results are encouraging, since it appears that the action of NSAIDs, globally considered, may be beneficial upon the loosening process. The inhibitory effect of paracetamol upon TNF-alpha and gelatinases is intriguing. Our data, if supported by similar observations, probably justify performance of long-term clinical trials.

Understanding the role of proteases and pH in wound healing

Recent research into chronic and non-healing wounds has helped increase our knowledge and understanding of the destructive processes that occur in wounds. Advanced dressings, such as protease-modulating dressings, have been developed to reduce the effects of these processes and re-establish a molecular balance in the wound bed. To use these dressings accurately, nurses need to understand the events that occur at a molecular level in the wound bed and the phases of wound healing so that they can act appropriately if a wound becomes 'stuck' in one of these phases.

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.