Enhanced cardiac production of matrix metalloproteinase-2 and -9 and its attenuation associated with pravastatin treatment in patients with acute myocardial infarction

Increased soluble programed cell death-ligand 1 is associated with acute coronary syndrome

BACKGROUND

Programmed cell death (PD)-1 and its ligand (PD-L1) plays crucial roles in T-cell tolerance as immune checkpoint. Previous studies reported that increased serum levels of soluble PD-L1 (sPD-L1) reflect myocardial and vascular inflammation. However, little is known about the clinical relationship between sPD-L1 and acute coronary syndrome (ACS). We investigated the relation of sPD-L1 and ACS.

METHODS

We prospectively measured serum levels of sPD-L1 using a commercially available enzyme-linked immunosorbent assay kit in patients with coronary artery disease (CAD) and continuous non-CAD admitted to Kumamoto University Hospital between December 2017 and June 2019. All malignant diseases, patients who underwent hemodialysis, active collagen diseases, and severe infectious diseases were excluded.

RESULTS

Totally, 446 CAD patients [ACS, n = 124; chronic coronary syndrome (CCS), n = 322] and 24 non-CAD patients were analyzed. The levels of sPD-L1 were significantly higher in patients with ACS than those both with non-CAD and CCS {ACS, 188.7 (111.0-260.8) pg/mL, p < 0.001 vs. non-CAD [83.5 (70.8-130.4) pg/mL]; and p = 0.009 vs. CCS [144.2 (94.8-215.5) pg/mL], respectively}. Univariate logistic regression analysis identified that sPD-L1 was significantly associated with ACS [odds ratio (OR): 1.459, 95% confidence interval (CI): 1.198-1.778, p < 0.001]. Multivariable logistic regression analysis with nine significant factors identified from the univariate analysis revealed that sPD-L1 was significantly and independently associated with ACS (OR: 1.561, 95% CI: 1.215-2.006, p < 0.001).

CONCLUSIONS

This is the first clinical study to demonstrate the increased level of sPD-L1 in patients with CAD, and the significant association with ACS.

Platelets and Matrix Metalloproteinases: A Bidirectional Interaction with Multiple Pathophysiologic Implications

Platelets contain and release several matrix metalloproteinases (MMPs), a highly conserved protein family with multiple functions in organism defense and repair. Platelet-released MMPs as well as MMPs generated by other cells within the cardiovascular system modulate platelet function in health and disease. In particular, a normal hemostatic platelet response to vessel wall injury may be transformed into pathological thrombus formation by platelet-released and/or by locally generated MMPs. However, it is becoming increasingly clear that platelets play a role not only in hemostasis but also in immune response, inflammation and allergy, atherosclerosis, and cancer development, and MMPs seem to contribute importantly to this role. A deeper understanding of these mechanisms may open the way to novel therapeutic approaches to the inhibition of their pathogenic effects and lead to significant advances in the treatment of cardiovascular, inflammatory, and neoplastic disorders.

Dose-Dependent Inhibitory Effect of Rosuvastatin in Japanese Patients with Acute Myocardial Infarction on Serum Concentration of Matrix Metalloproteinases-INVITATION Trial

Aim: Matrix metalloproteinases (MMPs) play critical roles in acute myocardial infarction (AMI). This trial was conducted to determine the potential effects of higher-dose rosuvastatin on circulating MMP levels in patients with AMI.

Methods: This was a multicenter, open-label, 1:1 randomized, parallel-group study. Patients with AMI were randomly assigned to the appropriate-dose group (10 mg rosuvastatin once daily) or the low-dose group (2.5 mg rosuvastatin once daily) within 24 hours after percutaneous coronary intervention. MMP-2 and MMP-9 levels were measured on day 1 and at week 4, 12, and 24 after enrollment. The primary endpoint was the change in MMP levels at 24 weeks after enrollment. The secondary endpoints were change in MMP levels at day 1 and weeks 4 and 12 after enrollment.

Results: Between August 2017 and October 2018, 120 patients with AMI from 19 institutions were randomly assigned to either the appropriate-dose or the low-dose group. There were 109 patients who completed the 24-week follow-up. The primary endpoint for both MMP-2 and MMP-9 was not significantly different between the two groups. The change in the active/total ratio of MMP-9 at week 12 after baseline was significantly lower in the appropriate-dose group compared with the low-dose group (0.81 [−52.8–60.1]% vs. 70.1 [−14.5–214.2]%, P =0.004), while the changes in MMP-2 were not significantly different between the two groups during the study period.

Conclusions: This study could not demonstrate the superiority of appropriate-dose of rosuvastatin in inhibiting serum MMPs levels in patients with AMI.

Dose-dependent INhibitory effect of rosuVastatin In Japanese patienTs with Acute myocardial infarcTION on serum concentration of matrix metalloproteinases - INVITATION trial

BACKGROUND

Acute myocardial infarction (AMI) is mainly characterized by the rupture of lipid-rich vulnerable atherosclerotic plaque. The matrix metalloproteinases (MMPs) have been shown to play a critical role in inflammatory processes underlying plaque rupture. Some reports suggested statins inhibit the increased MMP levels after AMI. However, there are a few comparison studies between the different dosages of the same statin and circulating levels of MMPs.

PURPOSE

This study will preliminarily investigate the potential effects of appropriate or low dose of rosuvastatin on circulating MMPs levels in AMI patients. Moreover, we will also obtain plasma from patients while undergoing diagnostic angiography to determine differences in various cardiac sites and peripheral vessels.

METHODS

This study is a multicenter, open-label, randomized, parallel-group study to be conducted to compare the appropriate or low dose of rosuvastatin in the effect on serum levels of inflammatory markers in AMI patients. The eligible patients undergoing percutaneous coronary intervention (PCI) will be randomly assigned to receive either appropriate or low-dose rosuvastatin daily using a web-based randomization software within 24h after PCI. The low-dose group will be treated with rosuvastatin 2.5mg once daily with a follow-up. The appropriate-dose group will begin treatment with rosuvastatin 5mg once daily, and the dose of rosuvastatin will be titrated to 10mg within 4 weeks. During administration of the study treatment, subjects will undergo laboratory testing including MMPs and be monitored for the occurrence of adverse events up to 24 weeks. The primary endpoint will be the change rate of MMPs at 24 weeks after administration.

CONCLUSIONS

INVITATION will compare the appropriate or low dose of rosuvastatin in the effects on serum levels of inflammatory markers including MMPs in AMI patients. This study will provide significant information on rosuvastatin as an anti-inflammatory agent for AMI.

Matrix Metalloproteinases in Myocardial Infarction and Heart Failure

Cardiovascular disease is the leading cause of death, accounting for 600,000 deaths each year in the United States. In addition, heart failure accounts for 37% of health care spending. Matrix metalloproteinases (MMPs) increase after myocardial infarction (MI) and correlate with left ventricular dysfunction in heart failure patients. MMPs regulate the remodeling process by facilitating extracellular matrix turnover and inflammatory signaling. Due to the critical role MMPs play during cardiac remodeling, there is a need to better understand the pathophysiological mechanism of MMPs, including the biological function of the downstream products of MMP proteolysis. Future studies developing new therapeutic targets that inhibit specific MMP actions to limit the development of heart failure post-MI are warranted. This chapter focuses on the role of MMPs post-MI, the efficiency of MMPs as biomarkers for MI or heart failure, and the future of MMPs and their cleavage products as targets for prevention of post-MI heart failure.

Serum lipids and cardiac function correlate with nitrotyrosine and MMP activity in coronary artery disease patients

AIMS

Peroxynitrite-matrix metalloproteinase (MMP) signalling has been shown to contribute to myocardial ischaemia/reperfusion injury and heart failure and to be influenced by hyperlipidaemia in preclinical models. Therefore, here we investigated the correlation between the markers of peroxynitrite-MMP signalling and hyperlipidaemia in patients with significant coronary stenosis.

METHODS

Five minutes before percutaneous coronary intervention (PCI), arterial blood samples were collected from 36 consecutive patients with coronary artery disease (CAD) selected for elective PCI.

RESULTS

Serum nitrotyrosine positively correlated with MMP-9 activity (r = 0·54, P = 0·01), but not with MMP-2 activity. Nitrotyrosine positively correlated with total (r = 0·58; P < 0·01) and LDL cholesterol (r = 0·55; P < 0·01), serum triglyceride (r = 0·47; P < 0·05), and creatinine (r = 0·42; P < 0·05) and negatively correlated with HDL cholesterol (r = -0·46; P < 0·05) and with left ventricular ejection fraction (LVEF; r = -0·55; P < 0·05), respectively. MMP-2 activity correlated positively with total (r = 0·55; P < 0·05) and LDL cholesterol (r = 0·45; P < 0·05). In statin-treated patients, a significantly reduced serum nitrotyrosine was found as compared to statin naives; however, MMP activities and serum cholesterol levels were not different. MMP-9 activity correlated with urea nitrogen (r = 0·42; P < 0·05) and LVEF (r = -0·73; P < 0·01). Serum creatinine correlated negatively with LVEF (r = -0·50, P < 0·01).

CONCLUSIONS

This is the first demonstration that (i) serum nitrotyrosine correlates with MMP-9 activity, (ii) lipid parameters correlate with nitrotyrosine and MMP-2 activity, (iii) myocardial function correlates with creatinine, nitrotyrosine and MMP-9 activity, and (iv) creatinine correlates with nitrotyrosine and urea nitrogen with MMP-9 activity in patients with CAD. Studying the biomarkers of peroxynitrite-MMP pathway in large prospective trials may reveal their diagnostic avails.

Oral sophocarpine protects rat heart against pressure overload-induced cardiac fibrosis

CONTEXT

Sophocarpine, a tetracyclic quinolizidine alkaloid, is one of the most abundant active ingredients in Sophora alopecuroides Linn. (Kudouzi). Sophocarpine injection was found to have significant antiviral effects against coxsackievirus B3 and therapeutic effects for viral myocarditis in the clinic.

OBJECTIVE

This study assessed the effects of sophocapine on overload-induced cardiac fibrosis and investigated potential mechanisms.

MATERIALS AND METHODS

Adult male Sprague-Dawley rats were subjected to a suprarenal abdominal aorta constriction (AC) or sham to induce sustained pressure overload. Six weeks later, rats were randomly assigned to receive sophocapine (10, 20, and 40 mg/kg, gavage) or vehicle treatment for an additional 6 weeks. Six weeks after treatment, cardiac dysfunction, cardiac coefficient, cardiac fibrosis, hydroxyproline concentration, and inflammation mediators were examined.

RESULTS

When compared with the model group, the left ventricular weight/body weight decreased by 25.4% and 39.0% in 20 and 40 mg/kg sophocarpine groups, respectively. The beneficial effects were associated with amelioration of left ventricular systolic pressure (LVSP) and left ventricular enddiastolic pressure (LVEDP). Moreover, pressure overload-induced cardiac fibrosis was attenuated in sophocarpine treated groups. Importantly, sophocarpine (20 and 40 mg/kg) decreased pro-inflammatory cytokine levels (IL-6, 14.6% and 18.5%; IL-1β, 23.1% and 32.6%), collagen content (27.7% and 50.1%), as well as matrix metalloproteinases-2, 9 (MMP-2, 9) expression (MMP-2, 11.8% and 18.5%; MMP-9, 16.2% and 21.1%). Sophocarpine (40 mg/kg) inhibited IκB-α phosphorylation (19.0%).

CONCLUSION

These findings indicated that sophocarpine potentially had antifibrotic effects. The mechanism might be due to modulation of the balance between pro-inflammatory cytokine expression and collagen content level as well as MMPs expression via the NF-κB signaling pathway.

Matrix metalloproteinase-9: Many shades of function in cardiovascular disease

Matrix metalloproteinase (MMP)-9, one of the most widely investigated MMPs, regulates pathological remodeling processes that involve inflammation and fibrosis in cardiovascular disease. MMP-9 directly degrades extracellular matrix (ECM) proteins and activates cytokines and chemokines to regulate tissue remodeling. MMP-9 deletion or inhibition has proven overall beneficial in multiple animal models of cardiovascular disease. As such, MMP-9 expression and activity is a common end point measured. MMP-9 cell-specific overexpression, however, has also proven beneficial and highlights the fact that little information is available on the underlying mechanisms of MMP-9 function. In this review, we summarize our current understanding of MMP-9 physiology, including structure, regulation, activation, and downstream effects of increased MMP-9. We discuss MMP-9 roles during inflammation and fibrosis in cardiovascular disease. By concentrating on the substrates of MMP-9 and their roles in cardiovascular disease, we explore the overall function and discuss future directions on the translational potential of MMP-9 based therapies.

Therapeutic potential of matrix metalloproteinases in Duchenne muscular dystrophy

Matrix metalloproteinases (MMPs) are secreted proteinases that have physiologic roles in degradation and remodeling of extracellular matrix (ECM) in almost all tissues. However, their excessive production in disease conditions leads to many pathological features including tissue breakdown, inflammation, cell death, and fibrosis. Duchenne Muscular dystrophy (DMD) is a devastating genetic muscle disorder caused by partial or complete loss of cytoskeletal protein dystrophin. Progressive muscle wasting in DMD is accompanied by myofiber necrosis followed by cycles of regeneration and degeneration and inflammation that eventually result in replacement of myofiber by connective and adipose tissues. Emerging evidence suggests that gene expression and the activity of various MMPs are aberrantly regulated in muscle biopsies from DMD patients and in skeletal muscle of animal models of DMD. Moreover, a few studies employing genetic mouse models have revealed that different MMPs play distinct roles in disease progression in DMD. Modulation of the activity of MMPs improves myofiber regeneration and enhances the efficacy of transplantation and engraftment of muscle progenitor cells in dystrophic muscle in mouse models of DMD. Furthermore, recent reports also suggest that some MMPs especially MMP-9 can serve as a biomarker for diagnosis and prognosis of DMD. In this article, we provide a succinct overview of the regulation of various MMPs and their therapeutic importance in DMD.

Immediate administration of atorvastatin decreased the serum MMP-2 level and improved the prognosis for acute heart failure

BACKGROUND AND PURPOSE

We have reported that matrix metalloproteinase-2 (MMP-2) increased in acute heart failure (AHF) and better prognosis was found in patients with greater reduction in MMP-2. We assessed whether a statin decreased MMP-2 in AHF.

METHODS AND RESULTS

The serum MMP-2 levels were measured on admission (Day 1), Day 3, Day 7, and Day 14 in 50 AHF patients. The patients were randomized to either atorvastatin (n=25) or control group (n=25). Atorvastatin (10-20mg/day) was started within 12h after their admission and then was continued for two weeks. There were no differences in the serum levels of MMP-2 on Day 1 between atorvastatin group (1400.4±318.6ng/ml) and control group (1292.7±384.7ng/ml). MMP-2 significantly decreased in both groups on Day 3, 7, and 14. However, the MMP-2 value on Day 3 compared to Day 1 was observed to have decreased significantly in atorvastatin group (561.8±235.1ng/ml) compared to control group (272.6±270.6ng/ml; p=0.001). HF events which were defined as death from HF, readmission to hospital for HF, or prolonged hospital stay because of uncontrollable HF, occurred more in control group than in atorvastatin group. Kaplan-Meier curves showed that the prognosis of HF was significantly better in atorvastatin group as compared with control group (log-rank test, p=0.037).

CONCLUSION

In addition to conventional HF therapy, an early start of atorvastatin caused a great decrease in MMP-2 and also improved HF events in AHF.

Myocardial remodeling: cellular and extracellular events and targets

The focus of this review is on translational studies utilizing large-animal models and clinical studies that provide fundamental insight into cellular and extracellular pathways contributing to post-myocardial infarction (MI) left ventricle (LV) remodeling. Specifically, both large-animal and clinical studies have examined the potential role of endogenous and exogenous stem cells to alter the course of LV remodeling. Interestingly, there have been alterations in LV remodeling with stem cell treatment despite a lack of long-term cell engraftment. The translation of the full potential of stem cell treatments to clinical studies has yet to be realized. The modulation of proteolytic pathways that contribute to the post-MI remodeling process has also been examined. On the basis of recent large-animal studies, there appears to be a relationship between stem cell treatment post-MI and the modification of proteolytic pathways, generating the hypothesis that stem cells leave an echo effect that moderates LV remodeling.

Association of polymorphisms of zinc metalloproteinases with clinical response to stem cell therapy

AIM

The purpose of this study was to assess the associations of polymorphisms in two metalloproteinase genes-metalloproteinase-2 (MMP-2) and angiotensin converting enzyme (ACE)-with clinical response to autologous transplantation of mononuclear bone marrow cells (MBMC) in patients with acute myocardial infarction.

METHODS

The double centre study included 48 patients with a first acute myocardial infarction treated with primary coronary angioplasty, stent implantation and transplantation of MBMC. According to the changes in perfusion defect size, left ventricle ejection fraction, end-systolic volume and peak systolic velocity of the infracted wall (dSaMI) after cell therapy, the patients were retrospectively divided into group A (responders) and group B (non-responders). Genomic DNA was isolated from peripheral leukocytes by a standard technique using proteinase K. Three MMP-2 promoter (-1575G/A, -1306C/T and -790T/G) as well as I/D ACE gene polymorphisms were detected by PCR methods with restriction analyses (when necessary) according to standard protocols.

RESULTS

Of the 48 patients who received MBMC transplantation, 17 responded to the therapy. There were no significant differences in the prevalence of matrix metalloproteinase-2 triple genotype GGCCTT between responder/non-responder groups (71% versus 61%, p=0.375). Similarly, no differences in either genotype distribution or allelic frequencies of I/D ACE polymorphism between responders and non-responders to the cell therapy were observed (p=0.933). Compared to patients with ACE genotype ID or DD, the patients with ACE II genotype significantly improved in regional systolic LV function of the infarcted wall after implantations of MBMC (dSaMI - 0.4 versus 1.4 cm/s, p=0.037).

CONCLUSION

In our study, the ACE genotype II was associated with improvement of regional systolic LV function of the infarcted wall after implantations of MBMC. The detected polymorphism in matrix metalloproteinase-2 gene was not associated with clinical response to cell therapy.

Clinical significance of matrix metalloproteinase (MMP)-2 in patients with acute heart failure

The serum levels of matrix metalloproteinases (MMPs) increase during chronic heart failure (HF) and the MMP-2 are related to a poor prognosis. However, the roles of MMP-2 in acute HF (AHF) remain unclear. We investigated the change and clinical significance of MMP-2 in these conditions. The serum levels of MMP-2 were measured in 83 AHF patients before starting treatment (day 1), 3 (day 3) and 7 (day 7) days after admission, and before discharge (predischarge). MMP-2 decreased rapidly and significantly from day 3 to day 1 (902.9 ± 304.2 versus 1220.4 ± 330.5 ng/mL; P < 0.0001), whereas that of MMP-2 was not significantly different on day 7 and at predischarge (894.7 ± 278.9 and 920.0 ± 269.6 ng/mL, respectively) compared to day 3. We evaluated the relationships between ΔMMPs, defined as the changes in MMPs from day 1 to day 3 and HF events including cardiac death, readmission to hospital for HF, and uncontrollable HF. The MMP-2 value was significantly (P = 0.004) more decreased in the event-free group (381.4 ± 256.5 ng/mL) than in the event group (211.9 ± 225.5 ng/mL) between day 1 and day 3. The results of the multivariate logistic regression model for predicting HF events found that the specific factor for HF events was ΔMMP-2. Cutoff values of ΔMMP-2 were determined and event-free curves were constructed. Kaplan-Meier curves showed that the prognosis was significantly better among the patients with reductions in ΔMMP-2 values of more than 342 ng/mL. The serum levels of MMP-2 decreased with improvements in AHF. Rapid decreases in MMP-2 may be important for a better clinical outcome in patients with AHF.

Platelets release matrix metalloproteinase-2 in the coronary circulation of patients with acute coronary syndromes: possible role in sustained platelet activation

AIMS

To investigate whether selected matrix metalloproteinases (MMPs) are released in the coronary circulation of patients with acute coronary syndrome (ACS), whether this release is related to platelet activation, and whether it contributes to sustained platelet activation.

METHODS AND RESULTS

Blood from the aorta (Ao) and the coronary sinus (Cs) was obtained from 21 controls (non-cardiac chest pain), 24 stable angina (SA), and 30 ACS patients, before performing percutaneous transluminal coronary angioplasty. Selected MMPs, some platelet activation- and atheroma-related markers, and the platelet activation-potentiating activity of plasma were measured. Total MMP-2, active MMP-2, and MMP-9 were released in the coronary circulation of patients with ACS, but not of those with SA or controls. Similarly, transcoronary gradients of β-thromboglobulin (β-TG) and platelet factor 4, two platelet-specific proteins, and of soluble CD40L and secretory phospholipase A₂ (sPLA₂), markers of inflammation and platelet activation, were higher in ACS patients than in the other groups. In contrast, plasma monocyte chemoattractant protein-1, a platelet-unrelated marker of atherogenesis, was not increased in the Cs compared with Ao in any of the groups. Transcoronary gradients of both β-TG and sPLA₂ correlated with those of total and active MMP-2 in ACS, but not in controls or SA. Plasma from the Cs of ACS patients potentiated platelet activation, an effect suppressed by the specific MMP-2-inhibitor, tissue inhibitor of MMP-2 (TIMP-2).

CONCLUSION

Matrix metalloproteinase-2 is released in the coronary circulation of ACS patients, derives in part from activated platelets, and may contribute to sustained intracoronary platelet activation.

Matrix metalloproteinase inhibitor batimastat alleviates pathology and improves skeletal muscle function in dystrophin-deficient mdx mice

Duchenne muscular dystrophy (DMD), caused by mutations in the dystrophin gene, involves severe muscle degeneration, inflammation, fibrosis, and early death in afflicted boys. Matrix metalloproteinases (MMPs) are extracellular proteases that cause tissue degradation in several disease states. In this study, we tested the hypothesis that the expression levels of various MMPs are abnormally increased and that their inhibition will ameliorate muscle pathogenesis in animal models of DMD. Our results show that the transcript levels of several MMPs are significantly up-regulated, whereas tissue inhibitors of MMPs are down-regulated, in dystrophic muscle of mdx mice. Chronic administration of batimastat (BB-94), a broad spectrum peptide inhibitor of MMPs, reduced necrosis, infiltration of macrophages, centronucleated fibers, and the expression of embryonic myosin heavy chain in skeletal muscle of mdx mice. Batimastat also reduced the expression of several inflammatory molecules and augmented the levels of sarcolemmal protein beta-dystroglycan and neuronal nitric oxide in mdx mice. In addition, muscle force production in isometric contraction was increased in batimastat-treated mdx mice compared with those treated with vehicle alone. Furthermore, inhibition of MMPs using batimastat reduced the activation of mitogen-activated protein kinases and activator protein-1 in myofibers of mdx mice. Our study provides the novel evidence that the expression of MMPs is atypically increased in DMD, that their inhibition ameliorates pathogenesis, and that batimastat could prove to be a significant candidate for DMD therapy.

c-Jun DNAzymes Inhibit Myocardial Inflammation, ROS Generation, Infarct Size, and Improve Cardiac Function After Ischemia-Reperfusion Injury

Objectives— Coronary reperfusion has been the mainstay therapy for reduced infarct size after a heart attack. However, this intervention also results in myocardial injury by initiating a marked inflammatory reaction, and new treatments are keenly sought.

Methods and Results— The basic-region leucine zipper protein, c-Jun is poorly expressed in the normal myocardium and is induced within 24 hours after myocardial ischemia-reperfusion injury. Synthetic catalytic DNA molecules (DNAzymes) targeting c-Jun (Dz13) reduce infarct size in the area-at-risk (AAR) regardless of whether it is delivered intramyocardially at the initiation of ischemia or at the time of reperfusion. Dz13 attenuates neutrophil infiltration, c-Jun and ICAM-1 expression in vascular endothelium, cardiomyocyte apoptosis, and the generation of reactive oxygen species in the reperfused myocardium. It inhibits infiltration into the AAR of complement 3 (C3), C3a receptor (C3aR), membrane attack complex-1 (Mac-1), or matrix metalloproteinase-2 (MMP-2) positive inflammatory cells. Dz13 also improves cardiac function without influencing myocardial vascularity or fibrosis.

Conclusion— These findings demonstrate the regulatory role of c-Jun in the pathogenesis of myocardial inflammation and infarction following ischemia-reperfusion injury, and inhibition of this process using catalytic DNA.

Noninvasive limb ischemic preconditioning protects against myocardial I/R injury in rats

BACKGROUND

Transient limb ischemia induces remote early preconditioning that protects the myocardium from ischemia/reperfusion (I/R). However, it is unknown whether limb ischemia induces remote late preconditioning and whether it induces the same magnitude of cardioprotection compared with cardial ischemic preconditioning (CIP). We tested the hypothesis that late remote preconditioning of noninvasive limb ischemia (NLIP) offers the same magnitude of cardioprotection against myocardium I/R injury.

METHODS

Thirty Wistar rats weighing 240-260 g each were randomly divided into three groups: I/R, CIP, and NLIP. The mean arterial pressure (MAP), heart rate (HR), ST-segment, ventricular arrhythmia, and CK-MB, cTnI, and superoxide dismutase (SOD) activity were measured after 0 and 30 min of ischemia and after 120 min of reperfusion. Myocardial infarct size, histologic examination, MMP-2, MMP-9, and TIMP-1 protein expression were determined at the end of the experiment.

RESULTS

Compared with I/R groups, CIP and NLIP reduced ST-segment elevation (P<0.01), decreased incidence and duration of ventricular arrhythmia (P<0.01) during ischemia, decreased CK-MB (P<0.05), and cTnI (P<0.01) activity, and increased SOD (P<0.05) activity after reperfusion. The myocardial infarct size (P<0.01) was significantly reduced, and cell injury was attenuated in the CIP and NLIP groups compared with the I/R group. MMP-2 and MMP-9 protein expression was significantly decreased in the CIP and NLIP groups (P<0.01), while TIMP-1 expression was significantly increased in the CIP and NLIP groups compared with the I/R group (P<0.01).

CONCLUSION

Remote preconditioning via NLIP has late cardioprotection against myocardium I/R injury and has a similar magnitude of cardioprotection compared with CIP in rats.

Comparison effect of atorvastatin (10 versus 80 mg) on biomarkers of inflammation and oxidative stress in subjects with metabolic syndrome

Metabolic syndrome (MS), characterized by low-grade inflammation, confers an increased risk for cardiovascular disease. Statins, in addition to having lipid-lowering effects, have pleiotropic effects and decrease biomarkers of inflammation and oxidative stress. The Treating to New Target Study showed a greater decrease in low-density lipoprotein (LDL) cholesterol and cardiovascular events with atorvastatin 80 mg versus 10 mg in patients with MS with coronary heart disease. However, part of this benefit could be caused by the greater pleiotropic effects of the higher dose of atorvastatin. The dose-response effect of atorvastatin on biomarkers of inflammation and oxidative stress has not been investigated in subjects with MS. Thus, the dose-response effect of atorvastatin on biomarkers of inflammation (high-sensitivity C-reactive protein [hs-CRP], matrix metalloproteinase-9, and nuclear factor-kappaB [NF-kB] activity) and oxidative stress (oxidized LDL, urinary nitrotyrosine, F2-isoprostanes, and monocyte superoxide release) was tested in a randomized double-blind clinical trial in subjects with MS. Seventy subjects were randomly assigned to receive placebo or atorvastatin 10 or 80 mg/day for 12 weeks. A strong dose-response (atorvastatin 10 compared with 80 mg, p <0.05) was observed for changes in total, LDL (32% and 44% reduction), non-high-density lipoprotein (28% and 40% reduction), and oxidized LDL cholesterol (24% and 39% reduction) at atorvastatin 10 and 80 mg, respectively. Hs-CRP, matrix metalloproteinase-9, and NF-kB significantly decreased in the 80-mg atorvastatin group compared with baseline. In conclusion, this randomized trial of subjects with MS showed the superiority of atorvastatin 80 mg compared with its 10-mg dose in decreasing oxidized LDL, hs-CRP, matrix metalloproteinase-9, and NF-kB activity.

Matrix metalloproteinase dysregulation in HIV infection: implications for therapeutic strategies

The emerging role of immune activation and inflammation in the pathogenesis of human immunodeficiency virus (HIV) disease has stimulated the search for new approaches for managing HIV infection. Recent evidence suggests that an imbalance between matrix metalloproteinases (MMPs) and endogenous tissue inhibitors of MMPs (TIMPs) might contribute to HIV-associated pathology by inducing remodelling of the extracellular matrix. Here, we discuss the evidence and the potential mechanisms for altered MMP or TIMP function in HIV infection and disease. Furthermore, we outline the possible medical implications for the use of compounds that target MMP activity, and we propose that antiretroviral drugs, particularly HIV protease inhibitors (PIs), and compounds with anti-inflammatory properties, such as statins, natural omega-3 fatty acids and tetracyclines, which inhibit MMP function, might represent useful therapeutic approaches to mitigate potential MMP-related damage during HIV infection.

Erythropoietin protects post-ischemic hearts by preventing extracellular matrix degradation: role of Jak2-ERK pathway

Factors predisposing to extracellular matrix degradation associated with myocardial ischemia/reperfusion (IR) usually cause cell death. Recombinant human erythropoietin (EPO) protects the myocardium from IR, but whether it affects extracellular matrix (ECM) degradation is not known. This study examined the effect of the Jak2-ERK pathway, which is triggered by EPO, on the expression of matrix metalloproteinases (MMPs), tissue inhibitor of MMP 4 (TIMP-4), and collagen in post-ischemic hearts. Rat hearts were isolated and perfused in a Langendorff apparatus. IR was induced by 40 min of stopped flow and 120 min of aerobic reperfusion; EPO was added immediately before reperfusion. Compared to untreated controls, poor recovery of the left ventricular developed pressure (LVDP) was seen in IR hearts. IR resulted in myocyte injury measured by creatine kinase MB release and infarction. Western blot analysis showed increased levels of MMP-2 and MMP-9 and reduced levels of TIMP-4 and collagen III. IR rats given 5 IU/ml of EPO showed improved LVDP with reduced injury. EPO increased Jak2 and ERK activity, decreased MMP expression, increased TIMP-4 expression, and prevented collagen degradation in IR hearts. All these effects were blocked by the upstream ERK inhibitor, U0126 (5 microM). These observations show that EPO attenuates extracellular matrix degradation following IR and this may be the basis of the protection from cell death. Jak2-ERK phosphorylation may be an important signal in this process.

MMPs as therapeutic targets--still a viable option?

Matrix metalloproteinases (MMPs) appear to be ideal drug targets--they are disease-associated, extracellular enzymes with a dependence on zinc for activity. This apparently straightforward target, however, is much more complex than initially realized. Although disease associated, the roles for particular enzymes may be healing rather than harmful making broad-spectrum inhibition unwise; targeting the catalytic zinc with specificity is difficult, since other related proteases as well as non-related proteins can be affected by some chelating groups. While the failure of early-generation MMP inhibitors dampened enthusiasm for this type of drug, there has recently been a wealth of studies examining the basic biology of MMPs which will greatly inform new drug trials in this field.

Lovastatin protects mesenchymal stem cells against hypoxia- and serum deprivation-induced apoptosis by activation of PI3K/Akt and ERK1/2

Cell therapy with bone marrow-derived mesenchymal stem cells (MSCs) has been shown to have great promises in cardiac repair after myocardial infarction. However, poor viability of transplanted MSCs in the infracted heart has limited the therapeutic efficacy. Our previous studies have shown in vitro that rat MSCs undergo caspase-dependent apoptosis in response to hypoxia and serum deprivation (Hypoxia/SD). Recent findings have implicated statins, an established class of cholesterol-lowering drugs, enhance the survival of cells under various conditions. In this study, we investigated the effect of lovastatin on rat MSCs apoptosis induced by Hypoxia/SD, focusing in particular on regulation of mitochondrial apoptotic pathway and the survival signaling pathways. We demonstrated that lovastatin (0.01-1 microM) remarkably prevented MSCs from Hypoxia/SD-induced apoptosis through inhibition of the mitochondrial apoptotic pathway, leading to attenuation of caspase-3 activation. The loss of mitochondrial membrane potential and cytochrome-c release from mitochondria to cytosol were significantly inhibited by lovastatin. Furthermore, the antiapoptotic effect of lovastatin on mitochondrial apoptotic pathway was effectively abrogated by both PI3K inhibitor, LY294002 and ERK1/2 inhibitor, U0126. The phosphorylations of Akt/GSK3 beta and ERK1/2 stimulated by lovastatin were detected. The activation of ERK1/2 was inhibited by a PI3K inhibitor, LY294002, but U0126, a ERK1/2 inhibitor did not inhibit phosphorylation of Akt and GSK3 beta. These data demonstrate that lovastatin protects MSCs from Hypoxia/SD-induced apoptosis via PI3K/Akt and MEK/ERK1/2 pathways, suggesting that it may prove a useful therapeutic adjunct for transplanting MSCs into damaged heart after myocardial infarction.