Acute exacerbations of COPD are associated with significant activation of matrix metalloproteinase 9 irrespectively of airway obstruction,emphysema and infection

Background

Acute exacerbations of chronic obstructive pulmonary disease (AE-COPD) are associated with accelerated aggravation of clinical symptoms and deterioration of pulmonary function. The mechanisms by which exacerbations may contribute to airway remodeling and declined lung function are poorly understood. In this study, we investigated if AE-COPD are associated with differential expression of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in bronchoalveolar lavage (BAL).

Methods

COPD patients undergoing diagnostic bronchoscopy, with either stable disease (n = 53) or AE-COPD (n = 44), matched for their demographics and lung function parameters were included in this study. Protein levels of MMP-2,–9,–12 and of TIMP-1 and -2 in BAL were measured by ELISA. Enzymatic activity of MMP-2 and -9 was assessed by gelatin zymography.

Results

We observed that MMP-9, TIMP-1 and TIMP-2 were significantly increased in BAL during AE-COPD. Furthermore, there was a significant negative correlation of MMP-9, TIMP-1 and TIMP-2 with FEV1% predicted and a significant positive correlation of TIMP-1 and TIMP-2 with RV% predicted in AE-COPD. None of MMPs and TIMPs correlated with DLCO% predicted, indicating that they are associated with airway remodeling leading to obstruction rather than emphysema. In AE-COPD the gelatinolytic activity of MMP-2 was increased and furthermore, MMP-9 activation was significantly up-regulated irrespective of lung function, bacterial or viral infections and smoking.

Conclusions

The results of this study indicate that during AE-COPD increased expression of TIMP-1, TIMP-2, and MMP-9 and activation of MMP-9 may be persistent aggravating factors associated with airway remodeling and obstruction, suggesting a pathway connecting frequent exacerbations to lung function decline.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-015-0240-4) contains supplementary material, which is available to authorized users.     

Unloading the infarcted heart affect MMPs–TIMPs axis in a rat cardiac heterotopic transplantation model

Ventricular assist devices may function as a bridge to recovery or heart transplantation, however, little is known about its mechanisms. This study examined the role of matrix metalloproteinases (MMP)-tissue inhibitors of metalloproteinases (TIMP) axis in the process of recovery after unloading in a rat ischemic-induce heart failure (HF) model. Myocardial infarction model was created with the coronary artery ligation. The infarcted rats hearts were unloaded by heterotopic cardiac transplantation (n = 14). 2 weeks later, the function of normal and infarcted hearts with or without loading was evaluated by Langendorff perfusion model. The hearts were then harvested and prepared for the study of expression of MMPs and TIMPs. Developed pressure in the unloading group was higher than the loading group (P = 0.0074). Unloading increased the ratio of TIMP-1–MMP-1(1.38 ± 0.11 vs. 0.76 ± 0.09, P < 0.05), TIMP-2–MMP-2 (1.06 ± 0.10 vs. 0.33 ± 0.07, P < 0.01), TIMP-3–MMP-9(1.07 ± 0.08 vs. 0.59 ± 0.06, P < 0.05). Although MMP-1, 2, 9 were downregulated (P < 0.01, 0.01, 0.05, respectively), TIMP-2 and TIMP-3 upregulated (P < 0.01, 0.05, respectively), MMP-7 and TIMP-1 was not affected significantly. The infarcted cardiac function could be improved by unloading. It was attributed to downregulation of MMP-1, 2 and 9, and upregulation of TIMP-2 and -3, and furthermore, the ratio of TIMPs to MMPs was increased, which might be more sensitive than sole MMPs or TIMPs for the judgment of myocardial matrix homeostasis.     

Angiotensin II receptor blockade improves matrix metalloproteinases/tissue inhibitor of matrix metalloproteinase-1 balance and restores fibronectin expression in rat infarcted myocardium

Matrix metalloproteinases (MMPs) and the tissue inhibitors of MMPs (TIMPs) have been recognized to play a pivotal role in matrix remodeling following myocardial infarction (MI). The aims of the present study were to examine the expression profile of MMPs/TIMP-1 after MI and to determine whether angiotensin II receptor (ATR) blockade improves MMPs/TIMP-1 balance. Compared with sham-operated rats, in vivo MI-induced a significant elevation of MMP-2, MMP-3 and MMP-9 levels and a marked reduction of TIMP-1 and fibronectin (FN) expressions in infarcted left ventricular free wall (LVFW) and hypertrophic interventricular septum (IS) but not in non-infarcted right ventricle (RV). In addition, regional MI increased MMP-2, MMP-3 and MMP-9, while decreased TIMP-1 and FN in infarcted LVFW and hypertrophic IS compared with the non-infarcted RV. Compared with vehicle-treated MI rats, oral valsartan, but not PD123319, limited infarct size, normalized MMPs/TIMP-1 balance and restored FN level. The present findings might further our understanding of the regulatory mechanisms of valsartan in myocardial remodeling after MI.     

Interferon-Gamma Increases the Ratio of Matrix Metalloproteinase-9/Tissue Inhibitor of Metalloproteinase-1 in Peripheral Monocytes from Patients with Coronary Artery Disease

Acute coronary syndromes (ACS) may be triggered by acute infections. Systemic production of interferon gamma (IFN-γ) is induced during infection and regulates the production of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), both important in plaque stability. This study evaluates the effect of IFN-γ on the MMPs/TIMP-1 ratio in cultured monocytes from 30 patients with stable coronary artery disease (CAD), 30 with unstable angina (UA) or non-ST-segment elevation myocardial infarction (NSTEMI), and 30 healthy blood donors. Supernatant concentrations of MMP-1, -2, -9, and TIMP-1 were measured by enzyme-linked immunoassays. Basal concentration of MMP-1 and TIMP-1 was similar between groups, while MMP-2 was higher in healthy individuals and MMP-9 in patients with UA/NSTEMI. Upon IFN-γ stimulation, MMP-9 secretion increased in all groups, while TIMP-1 decreased only in patients with CAD, which in turn result in a strikingly elevation in their mean MMP-9/TIMP-1 ratio. MMP-1/TIMP-1 and MMP-2/TIMP-1 ratios were <1.0 in basal conditions and after stimulation in all groups. Our results suggest that nonstimulated monocytes from patients with stable CAD show a similar behavior than those from healthy individuals. However, stimulation with IFN-γ induces an increase on the MMP-9/TIMP-1 ratio as high as that found in patients with ACS. Thus, it may bring biological plausibility to the association between acute infections and the development of ACS.     

Effect of compressive force on the expression of MMPs, PAs, and their inhibitors in osteoblastic Saos-2 cells

Bone matrix turnover is regulated by matrix metalloproteinases (MMPs), tissue inhibitors of matrix metalloproteinases (TIMPs), and the plasminogen activation system, including tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), and plasminogen activator inhibitor type-1 (PAI-1). We previously demonstrated that 1.0g/cm(2) of compressive force was an optimal condition for inducing bone formation by osteoblastic Saos-2 cells. Here, we examined the effect of mechanical stress on the expression of MMPs, TIMPs, tPA, uPA, and PAI-1 in Saos-2 cells. The cells were cultured in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum and with or without continuously compressive force (0.5-3.0g/cm(2)) for up to 24h. The levels of MMPs, TIMPs, uPA, tPA, and PAI-1 gene expression were estimated by determining the mRNA levels using real-time PCR, and the protein levels were determined using ELISA. The expression levels of MMP-1, MMP-2, MMP-14, and TIMP-1 markedly exceeded the control levels at 1.0g/cm(2) of compressive force, whereas the expression levels of MMP-3, MMP-13, TIMP-2, TIMP-3, TIMP-4, tPA, uPA, and PAI-1 markedly exceeded the control levels at 3.0g/cm(2). These results suggest that mechanical stress stimulates bone matrix turnover by increasing these proteinases and inhibitors, and that the mechanism for the proteolytic degradation of bone matrix proteins differs with the strength of the mechanical stress.     

Matrix metalloproteinase expression in primary lung fibroblasts of layer type chickens

Abstract

We attempted to determine the growth characteristics of cultured lung fibroblasts of layer type chickens and to investigate presence of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in these cells in vitro. Lung fibroblasts were isolated, characterized and subcultured from one-day-old layer type chicken lungs. Two different methods, explant culture and enzymatic techniques, were used for culturing and the results were compared. The presence of MMP-2 and TIMP-1 was shown in cultured fibroblasts by immunocytochemical staining, immune blotting and zymography methods. Immune expressions of neither MMP-9 nor TIMP-2 enzymes could be detected.     

机械性去负荷后心室明胶酶及其组织型抑制剂与细胞外基质变化

目的：探讨左心室在去除压力和容量负荷下心室组织基质金属蛋白酶-2和-9及金属蛋白酶组织型抑制剂-1和-2表达水平与细胞外基质沉积量的关系。方法：12周龄雄性Lewis大鼠建立Lewis-to-Lewis腹腔异位心脏移植模型,形成左心室去负荷状态,并以同龄雄性Lewis大鼠胸腔原位心脏作为对照。移植后14d采用天狼猩红-偏振光法对移植和对照组心脏的ECM沉积量进行分析。心室组织MMP-2和MMP-9活性检测采用明胶酶谱法。MMP-2、MMP-9、TIMP-1、TIMP-2的mRNA表达水平检测采用荧光定量PCR法;TIMP-1和TIMP-2蛋白含量采用Western blot测定。结果：手术后14d,与原位心脏比较,腹腔移植心脏心肌细胞横截面积减小,并伴有心肌ECM沉积量增多（胶原容积分数5．22％±1．6％VS2．21％±0．9％,P〈0．05）,并且MMP-2、MMP-9明胶酶活性明显增强,MMP-2、MMP-9及其组织型抑制剂T1MP-1、TIMP-2的mRNA表达均增加（P〈0．05）,但TIMP-1、TIMP-2增加幅度较MMP-2、MMP-9高,TIMP-1、TIMP-2的蛋白含量均增加（P〈0．05）,TIMP-1增加幅度更为明显。结论：左心室在去除压力和容量负荷状态下心脏心室组织胶原沉积量增加,伴有MMPs／TIMPs系统失衡,尤其是TIMPs系统的明显上调。     

Hydrogen sulfide protects against vascular remodeling from endothelial damage

Remodeling by its very nature implied synthesis and degradation of extracellular matrix (ECM) proteins. Although oxidative stress, matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) have been implicated in vascular remodeling, the differential role of MMPs versus TIMPs and oxidative stress in vascular remodeling was unclear. TIMP-3 induced vascular cell apoptosis, therefore, we hypothesized that during vascular injury TIMP-3, MMP-9 and -12 (elastin-degrading MMP) were increased, whereas MMP-2 (constitutive MMP) and TIMP-4 (cardioprotective TIMP) decreased. Because of the potent anti-oxidant, vasorelaxing, anti-hypertensive agent, hydrogen sulfide (H₂S) was used to mitigate the vascular remodeling due to the differential expression of MMP and TIMP. Carotid artery injury was created by inserting a PE-10 catheter and rotating several times before pulling out. The insertion hole was sealed. Mice were grouped: wild type (WT), wild-type damaged artery (WTD), WT + NaHS (sodium hydrogen sulfide, precursor of H₂S) treatment (30 μmol/L in drinking water/6 weeks) and WTD + NaHS treatment. Carotid arteries were analyzed for oxidative stress and remodeling, by measuring super oxide dismutase-1 (SOD1), p47 (NADPH oxidase subunit), nitrotyrosine, MMPs and TIMPs by in situ immunolabeling and by Western blot analyses. The results suggested robust increase in p47, nitrotyrosine, MMP-9, MMP-12, TIMP-3 and decrease in SOD1 and MMP-2 levels in the injured arteries. The treatment with H₂S ameliorated these effects. We concluded that p47, TIMP-3, MMP-9 and -12 were increased where as SOD-1, MMP-2 and TIMP-4 were decreased in the injured arteries. The treatment with H₂S mitigated the vascular remodeling by normalizing the levels of redox stress, MMPs and TIMPs.     

Complex role of matrix metalloproteinases in angiogenesis

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) play a significant role in regulating angiogenesis,the process of new blood vessel formation.Interstitial collagenase (MMP-1),72kDa gelatinase A/type IV collagenase (MMP-2),and 92 kDA gelatinase B/type IV collagenase (MMP-9) dissolve extracellular matrix (ECM) and may initiate and promote angiogenesis.TIMP-1,TIMP-2,TIMP-3,and possibly,TIMP-4 inhibit neovascularization.A new paradign is emerging that matrilysin (MMP-7),MMP-9,and metalloelastase (MMP-12) may block angiogenesis by converting plasminogen to angiostatin,which is one of the most potent angiogenesis antagonists.MMPs and TIMPs play a complex role in regulating angiogenesis.An understanding of the biochemical and cellular pathways and mechanisms of angiogenesis will provide important information to allow the control of angiogenesis,e.g.the stimulation of angiogenesis for coronary collateral circulation formation;while the inhibition for treating arthritis and cancer.     

Imbalances between Matrix Metalloproteinases (MMPs) and Tissue Inhibitor of Metalloproteinases (TIMPs) in Maternal Serum during Preterm Labor

Background

Matrix metalloproteinases (MMPs) are involved in remodeling of the extracellular matrix (ECM) during pregnancy and parturition. Aberrant ECM degradation by MMPs or an imbalance between MMPs and their tissue inhibitors (TIMPs) have been implicated in the pathogenesis of preterm labor, however few studies have investigated MMPs or TIMPs in maternal serum. Therefore, the purpose of this study was to determine serum concentrations of MMP-3, MMP-9 and all four TIMPs as well as MMP:TIMP ratios during term and preterm labor.

Methods

A case control study with 166 singleton pregnancies, divided into four groups: (1) women with preterm birth, delivering before 34 weeks (PTB); (2) gestational age (GA) matched controls, not in preterm labor; (3) women at term in labor and (4) at term not in labor. MMP and TIMP concentrations were measured using Luminex technology.

Results

MMP-9 and TIMP-4 concentrations were higher in women with PTB vs. GA matched controls (resp. p = 0.01 and p<0.001). An increase in MMP-9:TIMP-1 and MMP-9:TIMP-2 ratio was observed in women with PTB compared to GA matched controls (resp. p = 0.02 and p<0.001) as well as compared to women at term in labor (resp. p = 0.006 and p<0.001). Multiple regression results with groups recoded as three key covariates showed significantly higher MMP-9 concentrations, higher MMP-9:TIMP-1 and MMP-9:TIMP-2 ratios and lower TIMP-1 and -2 concentrations for preterm labor. Significantly higher MMP-9 and TIMP-4 concentrations and MMP-9:TIMP-2 ratios were observed for labor.

Conclusions

Serum MMP-9:TIMP-1 and MMP-9:TIMP-2 balances are tilting in favor of gelatinolysis during preterm labor. TIMP-1 and -2 concentrations were lower in preterm gestation, irrespective of labor, while TIMP-4 concentrations were raised in labor. These observations suggest that aberrant serum expression of MMP:TIMP ratios and TIMPs reflect pregnancy and labor status, providing a far less invasive method to determine enzymes essential in ECM remodeling during pregnancy and parturition.     

Matrix metalloproteinase-9,-3 and tissue inhibitor of matrix metalloproteinase-1 in colorectal cancer: relationship to clinicopathological variables

The balance between matrix metalloproteinases (MMPs) and their physiological tissue inhibitors of matrix metalloproteinases (TIMPs) is crucial in tumour invasion and progression. The aim of this study was to investigate the levels of MMP-9, MMP-3 and TIMP-1 in colorectal cancer (CRC) and to evaluate these proteinases and their inhibitor with respect to clinicopathological variables. Activities of pro- and active MMP-9 were measured in paired tumour and distant normal tissue specimens from 43 patients with CRC using gelatin zymography. ELISA was employed for the determination of MMP-9, MMP-3 and TIMP-1 protein expressions. The activity levels of pro- and active MMP-9 and protein expression levels of MMP-9, MMP-3 and TIMP-1 were higher in tumour tissues than in the corresponding normal tissues; the differences being significant for all (p < 0.05), except TIMP-1. Similarly, active MMP-9/proMMP-9 and the ratio of protein expression level of MMP-9-TIMP-1 were found to be significantly higher in tumour tissues ( p < 0.01). Among all the clinicopathological variables investigated, significant correlations were found between MMP-9 and presence of perineural invasion, MMP-3 and lymph node status, TIMP-1 and tumour differentiation, MMP-9/TIMP-1 ratio and histological types ( p < 0.05). In conclusion, MMP-3 was not as notably increased as MMP-9 in tumour tissues. However, different roles may be attributed to MMP-9 and MMP-3 in CRC development and progression. Additionally, assessment of TIMP-1 in relation to MMPs appeared to be crucial in CRC studies to provide a basis for the re-evaluation of the clinical usefulness of TIMP-1 in colorectal cancer.     

Imbalanced circulating matrix metalloproteinases in polycystic ovary syndrome

Altered levels of matrix metalloproteinases (MMPs) may reflect relevant pathogenetic mechanisms of disease conditions. The objective of this study was to compare the plasma levels of MMPs and tissue inhibitors of MMPs (TIMPs) in polycystic ovary syndrome (PCOS) patients with those found in healthy ovulatory controls and to examine whether the levels of these biomarkers are associated with clinical and biochemical features of this syndrome. Sixty-five healthy ovulatory subjects (controls) and 80 patients with PCOS were include in this study. MMP-2, MMP-8, MMP-9, TIMP-1, TIMP-2 concentrations were measured in plasma samples by gelatin zymography or enzyme-linked immunoassays. MMP-2, MMP-8, MMP-9, and TIMP-1 levels were similar in PCOS patients and in healthy controls (P > 0.05). PCOS patients had lower plasma TIMP-2 levels than healthy controls (P < 0.05). We found higher MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios in PCOS patients than in healthy controls (all P < 0.05). Testosterone levels correlated positively with the MMP-9/TIMP-1 ratio and negatively with TIMP-2 levels (r = 0.26, P < 0.01 and r = -0.21, P = 0.02, respectively). In addition, only testosterone was an independent predictor of TIMP-2 levels (estimate = -0.35, P = 0.04) and the MMP-9/TIMP-1 ratio (estimate = 0.01, P = 0.04). We found evidence indicating that the balance between MMPs and TIMPs in women with PCOS is altered, probably due to androgen excess found in these women.     

Elevated serum MMP-9/TIMP-1 ratio in patients with homozygous familial hypercholesterolemia: Effects of LDL-apheresis

ObjectiveMatrix degradation within an atherosclerotic plaque is an important pathogenic factor in atherosclerosis, and is largely modulated by the balance between matrix metalloproteinases (MMPs) and their endogenous inhibitors (i.e., tissue inhibitor of MMPs [TIMPs]). Familial hypercholesterolemia (FH) is a rare inherited disorder associated with premature coronary heart disease. The aim of the present study was to examine MMP-9 and TIMP-1 on plasma and cellular mRNA levels in homozygous FH patients (n = 7) compared with age- and sex-matched heterozygous FH patients (n = 6), and with healthy subjects (n = 7), and to test whether once-weekly LDL-apheresis (three consecutive sessions) of homozygous FH patients show short-term effects on these variables.ResultsThe main findings were that (i) Compared to healthy control subjects, homozygous FH patients have significantly higher serum levels of MMP-9 and lower levels of TIMP-1, and consequently significantly higher MMP-9/TIMP-1 ratio, potentially reflecting higher MMP-9 activity. (ii) Peripheral blood mononuclear cells (PBMC) isolated from FH homozygotes have significantly higher mRNA levels of MMP-9 compared to cells from heterozygotes. (iii) TNFα-stimulated PBMC from FH homozygotes released borderline-significantly more MMP-9 than cells from heterozygotes and healthy controls. (iv) LDL-apheresis (one day before treatment versus fifteen days later, on the day after the weekly treatment) had no significant short-term effect on any of the MMP-9 and TIMP-1 variables measured in serum and cells.ConclusionsThe data may suggest that homozygous FH patients have an enhanced matrix degrading potential as compared with heterozygous FH patients and healthy controls, potentially contributing to the increased cardiovascular risk observed in these patients.     

Expression of matrix metalloproteinase (MMP)-2, MMP-14 and tissue inhibitor of matrix metalloproteinase (TIMP)-2 during bovine placentation and at term with or without placental retention

Matrix metalloproteinases (MMPs) and counteracting tissue inhibitors of metalloproteinases (TIMPs) are balancing extracellular matrix (ECM) formation and degradation. The latter is believed to be an important aspect for the detachment of fetal membranes postpartum when loosening the feto-maternal connection which is a prerequisite to avoid placental retention a common disease in cows leading to considerable economic loss. Membrane-type (MT) MMPs have been suggested as potential activators controlling ECM remodelling. In particular, MT1-MMP (MMP-14) is able to degrade ECM substrates and activate MMP-2 through binding TIMP-2 at the cell surface. Since the connection between the trophoblast and the maternal caruncular epithelium is supported by integrin receptors bound to ECM, we hypothesize that impaired modulation of the ECM by TIMPs/MMPs participates in the aetiology of bovine retained fetal membranes. To analyse this involvement, placentomes were collected from cows after term parturition and timely release of fetal membranes (n = 4) and cows with retained fetal membranes after various treatments for the induction of parturition using progesterone antagonist (aglepristone), PGF_2α analogue, glucocorticoid, and after elective caesarean sections (each group n = 3). The expression of MMP-14, MMP-2 and of TIMP-2 was examined by real-time-PCR, immunohistochemistry, Western blot and zymography. The relative mRNA expression levels of MMP-14 remained unchanged, while the expression levels of TIMP-2 and MMP-2 partly increased in animals with induced parturition and retention of fetal membranes compared to animals without placental retention. MMP-14 protein was expressed in cells of the uninucleated trophoblast, the fetal mesenchyme and maternal stroma. TIMP-2 was present exclusively in trophoblast giant cells, while MMP-2 could be detected in uninucleated trophoblast cells and the fetal mesenchyme. The presence of the activated enzyme was confirmed by zymography. In conclusion, MMP-14, MMP-2 and TIMP-2 are co-localized in the fetal compartment and therefore could influence the timely release of fetal membranes in cattle.     

Increased levels of leukocyte-derived MMP-9 in patients with stable angina pectoris

Objective

There is a growing interest for matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in plasma as novel biomarkers in coronary artery disease (CAD). We aimed to identify the sources of MMP-8, MMP-9, TIMP-1 and TIMP-2 among peripheral blood cells and further explore whether gene expression or protein release was altered in patients with stable angina pectoris (SA).

Methods

In total, plasma MMP-9 was measured in 44 SA patients and 47 healthy controls. From 10 patients and 10 controls, peripheral blood mononuclear cells (PBMC) and neutrophils were isolated and stimulated ex vivo. MMPs, TIMPs and myeloperoxidase were measured in plasma and supernatants by ELISA. The corresponding gene expression was measured by real-time PCR.

Results

Neutrophils were the dominant source of MMP-8 and MMP-9. Upon moderate stimulation with IL-8, the neutrophil release of MMP-9 was higher in the SA patients compared with controls (p<0.05). In PBMC, the TIMP-1 and MMP-9 mRNA expression was higher in SA patients compared with controls, p<0.01 and 0.05, respectively. There were no differences in plasma levels between patients and controls except for TIMP-2, which was lower in patients, p<0.01.

Conclusion

Measurements of MMPs and TIMPs in plasma may be of limited use. Despite similar plasma levels in SA patients and controls, the leukocyte-derived MMP-9 and TIMP-1 are significantly altered in patients. The findings indicate that the leukocytes are more prone to release and produce MMP-9 in symptomatic and angiographically verified CAD—a phenomenon that may have clinical implications in the course of disease.     

Increased plasma levels of matrix metalloproteinase-9 in patients with Alzheimer's disease

Matrix metalloproteinases (MMPs) may play a role in the pathophysiology of Alzheimer's disease (AD). MMP-9 and tissue inhibitors of metalloproteinases (TIMPs) are elevated in postmortem brain tissue of AD patients. MMPs and TIMPs are found in neurons, microglia, vascular endothelial cells and leukocytes. The aim of this study was to determine whether circulating levels of MMP-2, MMP-9, TIMP-1 and TIMP-2 are elevated in the plasma of AD patients. We compared AD patients to age- and gender-matched controls as well as to Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS) patients. There was constitutive expression of gelatinase A (MMP-2), and gelatinase B (MMP-9), in all the samples as shown by zymographic analysis. Levels of MMP-9 were significantly (P=0.003) elevated in the plasma of AD patients as compared to controls. Plasma levels of MMP-2, TIMP-1 and TIMP-2 were unchanged. There were no significant changes of MMP-2, MMP-9, TIMP-1 and TIMP-2 levels in PD and ALS samples. TIMP-1 and TIMP-2 were significantly correlated with MMP-9 in the AD patients. ApoE genotyping of plasma samples showed that levels of MMP-2, TIMP-1 and TIMP-2 and MMP-9 were not significantly different between the ApoE subgroups. These findings indicate that circulating levels of MMP-9 are increased in AD and may contribute to disease pathology.     

Expression of gelatinases and their tissue inhibitors in rat corpus luteum during pregnancy and postpartum

Extensive tissue remodeling occurs in the corpus luteum (CL) during both formation and luteolysis. Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are believed to play pivotal roles in these processes. In the present study, to evaluate the potential roles of matrix degrading proteases in luteal development and regression, we examined gelatinases and TIMP-1, -2, -3 mRNA expressions, as well as gelatinase activity in rat CL during pregnancy and postpartum using Northern blot, in situ hybridization, and gelatin zymography, respectively. The results showed that MMP-2 mRNA was only expressed at the early stages of pregnancy; TIMP-2 mRNA was highly expressed at the early and late pregnancy and day 1 postpartum, but could not be detected during the mid-phase of pregnancy; TIMP-3 mRNA expression was abundant during early pregnancy and peaked at day 7, but was absent from other time points examined. MMP-9 and TIMP-1 mRNAs in rat CL were below detectable level in the current study. Furthermore, the active MMP-2 was only present during the early stages of pregnancy, and no MMP-9 activity was observed in the zymogram. Taken together, our results suggest that MMP-2 and TIMP-3 may have functional roles in rat luteal formation, while TIMP-2 may be implicated in both formation and regression of the pregnant CL.