Temporal and spatial expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases following myocardial infarction

Transcriptome analysis reveals the regulation of miR-19b on inflammation in bovine mammary epithelial cells

MicroRNAs (miRNAs) are involved in various biological processes where they regulate the expression of mRNAs. Bovine mammary epithelial cells (bMECs) are functional cells that mediate mammary inflammatory immunity. Although numerous miRNAs regulate the function of bMECs, the role of miR-19b in bMECs has not been reported. In this study, the transcriptome of miR-19b overexpressed bMECs was analyzed by RNA-seq. Additionally, the differentially expressed genes (DEGs) were analyzed to establish the role of miR-19b in bMECs. The results revealed 269 DEGs between the miR-19b overexpression group and the negative control, including 199 up-regulated and 70 down-regulated genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that the DEGs regulated immune and inflammatory responses through Staphylococcus aureus (S. aureus) infection and phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway. In addition, the expression of miR-19b was significantly upregulated in lipophosphoric acid (LTA)-induced bMECs, and overexpression of miR-19b negatively regulated the expression of inflammatory cytokines IL-1β and IL-6, thereby alleviating the inflammatory response of LTA-induced bMECs. Based on the above results, we speculate that miR-19b may inhibit in dairy cow mammary inflammation caused by S. aureus, and this process may be mediated through the regulation of relevant gene expression and signaling pathways. The findings from this study provide a new reference for analyzing the molecular regulation of miR-19b in bMECs.

The role of matrix metalloproteinase-9 in cardiac remodeling and dysfunction and as a possible blood biomarker in heart failure

Heart failure (HF) is the leading cause of morbidity and mortality in cardiovascular diseases, being responsible for many hospitalizations annually. HF is considered a public health problem with significant economic and social impact, which makes searches essential for strategies that improve the ability to predict and diagnose HF. In this way, biomarkers can help in risk stratification for a more personalized approach to patients with HF. Preclinical and clinical evidence shows the participation of matrix metalloproteinase 9 (MMP-9) in the HF process. In this review, we will demonstrate the critical role that MMP-9 plays in cardiac remodeling and dysfunction. We will also show its importance as a blood biomarker in acute and chronic HF patients.

Emerging Therapeutic Targets for Acute Coronary Syndromes: Novel Advancements and Future Directions

Acute coronary syndrome (ACS) remains a major cause of morbidity and mortality worldwide, requiring ongoing efforts to identify novel therapeutic targets to improve patient outcomes. This manuscript reviews promising therapeutic targets for ACS identified through preclinical research, including novel antiplatelet agents, anti-inflammatory drugs, and agents targeting plaque stabilization. Preclinical studies have expounded these agents' efficacy and safety profiles in mitigating key pathophysiological processes underlying ACS, such as platelet activation, inflammation, and plaque instability. Furthermore, ongoing clinical trials are evaluating the efficacy and safety of these agents in ACS patients, with potential implications for optimizing ACS management. Challenges associated with translating preclinical findings into clinical practice, including patient heterogeneity and trial design considerations, are also discussed. Overall, the exploration of emerging therapeutic targets offers promising avenues for advancing ACS treatment strategies and improving patient outcomes.

The Anti-Atherosclerotic Effects of Endothelin Receptor Antagonist, Bosentan, in Combination with Atorvastatin-An Experimental Study

Bosentan, an endothelin receptor antagonist (ERA), has potential anti-atherosclerotic properties. We investigated the complementary effects of bosentan and atorvastatin on the progression and composition of the atherosclerotic lesions in diabetic mice. Forty-eight male ApoE-/- mice were fed high-fat diet (HFD) for 14 weeks. At week 8, diabetes was induced with streptozotocin, and mice were randomized into four groups: (1) control/COG: no intervention; (2) ΒOG: bosentan 100 mg/kg/day per os; (3) ATG: atorvastatin 20 mg/kg/day per os; and (4) BO + ATG: combined administration of bosentan and atorvastatin. The intra-plaque contents of collagen, elastin, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-a (TNF-a), matrix metalloproteinases (MMP-2, -3, -9), and TIMP-1 were determined. The percentage of lumen stenosis was significantly lower across all treated groups: BOG: 19.5 ± 2.2%, ATG: 12.8 ± 4.8%, and BO + ATG: 9.1 ± 2.7% compared to controls (24.6 ± 4.8%, p < 0.001). The administration of both atorvastatin and bosentan resulted in significantly higher collagen content and thicker fibrous cap versus COG (p < 0.01). All intervention groups showed lower relative intra-plaque concentrations of MCP-1, MMP-3, and MMP-9 and a higher TIMP-1concentration compared to COG (p < 0.001). Importantly, latter parameters presented lower levels when bosentan was combined with atorvastatin compared to COG (p < 0.05). Bosentan treatment in diabetic, atherosclerotic ApoE-/- mice delayed the atherosclerosis progression and enhanced plaques' stability, showing modest but additive effects with atorvastatin, which are promising in atherosclerotic cardiovascular diseases.

Study on therapeutic mechanism of total salvianolic acids against myocardial ischemia-reperfusion injury based on network pharmacology, molecular docking, and experimental study

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Salviae miltiorrhizae, also known as Danshen in Chinese, effectively activates the blood and resolves stasis. Total salvianolic acids (SA) is the main active ingredient of Danshen, and related preparations, such as salvianolate injection are commonly used clinically to treat myocardial ischemia-reperfusion injury (MIRI). However, the potential targets and key active ingredients of SA have not been sufficiently investigated.

AIM OF THE STUDY

This study aimed to investigate the mechanism of action of SA in treating MIRI.

MATERIALS AND METHODS

Network pharmacology and molecular docking techniques were used to predict SA targets against MIRI. The key acting pathway of SA were validated by performing experiments in a rat MIRI model.

RESULTS

Twenty potential ingredients and 54 targets of SA in treating MIRI were identified. Ingredient-target-pathway network analysis revealed that salvianolic acid B and rosmarinic acid had the highest degree value. Pathway enrichment analysis showed that SA may regulate MIRI through the IL-17 signaling pathway, and this result was confirmed in the rat MIRI experiment.

CONCLUSION

The results of this study indicate that SA may protect MIRI by regulating the IL-17 pathway.

The TIMP protein family: diverse roles in pathophysiology

The tissue inhibitors of matrix metalloproteinases (TIMPs) are a family of four matrisome proteins classically defined by their roles as the primary endogenous inhibitors of metalloproteinases (MPs). Their functions however are not limited to MP inhibition, with each family member harboring numerous MP-independent biological functions that play key roles in processes such as inflammation and apoptosis. Because of these multifaceted functions, TIMPs have been cited in diverse pathophysiological contexts. Herein, we provide a comprehensive overview of the MP-dependent and -independent roles of TIMPs across a range of pathological conditions. The potential therapeutic and biomarker applications of TIMPs in these disease contexts are also considered, highlighting the biomedical promise of this complex and often misunderstood protein family.

Changes in attachment and metabolic activity of rat neonatal cardiomyocytes and nonmyocytes caused by Macrovipera lebetina obtusa venom

The Caucasian viper Macrovipera lebetina obtusa (MLO) is one of the most prevalent and venomous snakes in the Caucasus and the surrounding regions, yet the effects of MLO venom on cardiac function remain largely unknown. We examined the influence of MLO venom (crude and with inhibited metalloproteinases and phospholipase A2) on attachment and metabolic activity of rat neonatal cardiomyocytes (CM) and nonmyocytes (nCM), assessed at 1 and 24 h. After exposing both CM and nCM to varying concentrations of MLO venom, we observed immediate cytotoxic effects at a concentration of 100 μg/ml, causing detachment from the culture substrate. At lower MLO venom concentrations both cell types detached in a dose-dependent manner. Inhibition of MLO venom metalloproteinases significantly improved CM and nCM attachment after 1-hour exposure. At 24-hour exposure to metalloproteinases inhibited venom statistically significant enhancement was observed only in nCM attachment. However, metabolic activity of CM and nCM did not decrease upon exposure to the lower dose of the venom. Moreover, we demonstrated that metalloproteinases and phospholipases A2 are not the components of the MLO venom that change metabolic activity of both CM and nCM. These results provide a valuable platform to study the impact of MLO venom on prey cardiac function. They also call for further exploration of individual venom components for pharmaceutical purposes.

Mechanism of pro-MMP9 activation in co-culture of pro-inflammatory macrophages and cardiomyocytes

OBJECTIVE

A wide range of cardiac diseases is associated with inflammation. "Inflamed" heart tissue is infiltrated with pro-inflammatory macrophages which extensively secrete matrix metalloproteinase 9 (MMP9), a regulator of extracellular matrix turnover. As MMP9 is released from macrophages in a latent form, it requires activation. The present study addresses the role of cardiomyocytes in the course of this activation process.

METHODS AND RESULTS

In mono- and co-cultures of pro-inflammatory rat macrophages (bone marrow-derived and peritoneal) and cardiomyocytes (H9C2 cell line) gelatin zymography demonstrated that activated macrophages robustly secreted latent pro-MMP9, whereas cardiomyocytes could not produce the enzyme. Co-culturing of the two cell species was critical for pro-MMP9 activation and was also accompanied by processing of cardiomyocyte-secreted pro-MMP2. A cascade of pro-MMP9 activation was initiated on macrophage membrane with pro-MMP2 cleavage. Namely, pro-inflammatory macrophages expressed an active membrane type 1 MMP (MT1MMP), which activated pro-MMP2, which in turn converted pro-MMP9. Downregulation of MT1MMP in macrophages by siRNA abolished activation of both pro-MMP2 and pro-MMP9 in co-culture. In addition, both cell species secreted MMP13 as a further pro-MMP9 activator. In co-culture, activation of pro-MMP13 occurred on membranes of macrophages and was enhanced in presence of active MMP2. Using incubations with recombinant MMPs and isolated macrophage membranes, we demonstrated that while both MMP2 and MMP13 individually had the ability to activate pro-MMP9, their combined action provided a synergistic effect.

CONCLUSION

Activation of pro-MMP9 in a co-culture of pro-inflammatory macrophages and cardiomyocytes was the result of a complex interaction of several MMPs on the cell membrane and in the extracellular space. Both cell types contributed critically to pro-MMP9 processing.

TIMP-1 in the prognosis of patients who underwent coronary artery bypass surgery: a 12-year follow-up study

Introduction

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) have been linked to clinical outcomes in patients with coronary artery disease (CAD). However, the prognostic value of TIMP-1 in patients with CAD who underwent coronary artery bypass grafting (CABG) has not been elucidated. We aimed to investigate the correlations of TIMP-1 with high-sensitivity C-reactive protein (hs-CRP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in the long-term prognosis of consecutive patients who underwent CABG.

Methods

A total of 234 patients (age: 70.4 ± 10.5 years, 84.6% men) with CAD who underwent CABG were prospectively enrolled. Preoperative levels of MMPs, TIMP-1, hs-CRP, and NT-proBNP were recorded. Major adverse cardiovascular events (MACE) were defined as non-fatal myocardial infarction, non-fatal stroke, and cardiovascular death.

Results

During a median follow-up of 12.1 years, 120 deaths were recorded. The deceased were older, had more manifest acute coronary syndrome (ACS), a lower left ventricular ejection fraction (LVEF), and an estimated glomerular filtration rate (eGFR), but significantly higher MMP13, TIMP-1, hs-CRP, and NT-proBNP compared with the survivors. After adjusting for age, sex, manifest ACS, eGFR, LVEF, total cholesterol, and triglycerides, TIMP-1 (hazard ratio and 95% confidence intervals per SD: 1.506, 1.183-1.917), hs-CRP (1.349, 1.183-1.561), and NT-ProBNP (1.707, 1.326-2.199) were all independently associated with all-cause mortality. The mediation analysis revealed that the mortality risks of TIMP-1 were partially mediated by NT-proBNP (62.2%) and hs-CRP (25.3%). The associations of TIMP-1 with MACE were partially mediated by NT-proBNP (54.4%) but not hs-CRP.

Conclusions

TIMP-1 was an independent predictor of long-term outcomes after CABG, with possible roles in subclinical inflammation and postoperative cardiac remodeling.

Potent inhibition of MMP-9 by a novel sustained-release platform attenuates left ventricular remodeling following myocardial infarction

Sustained drug-release systems prolong the retention of therapeutic drugs within target tissues to alleviate the need for repeated drug administration. Two major caveats of the current systems are that the release rate and the timing cannot be predicted or fine-tuned because they rely on uncontrolled environmental conditions and that the system must be redesigned for each drug and treatment regime because the drug is bound via interactions that are specific to its structure and composition. We present a controlled and universal sustained drug-release system, which comprises minute spherical particles in which a therapeutic protein is affinity-bound to alginate sulfate (AlgS) through one or more short heparin-binding peptide (HBP) sequence repeats. Employing post-myocardial infarction (MI) heart remodeling as a case study, we show that the release of C9-a matrix metalloproteinase-9 (MMP-9) inhibitor protein that we easily bound to AlgS by adding one, two, or three HBP repeats to its sequence-can be directly controlled by modifying the number of HBP repeats. In an in vivo study, we directly injected AlgS particles, which were bound to C9 through three HBP repeats, into the left ventricular myocardium of mice following MI. We found that the particles substantially reduced post-MI remodeling, attesting to the sustained, local release of the drug within the tissue. As the number of HBP repeats controls the rate of drug release from the AlgS particles, and since C9 can be easily replaced with almost any protein, our tunable sustained-release system can readily accommodate a wide range of protein-based treatments.

NKRF in Cardiac Fibroblasts Protects against Cardiac Remodeling Post-Myocardial Infarction via Human Antigen R

Myocardial infarction (MI) remains the leading cause of death worldwide. Cardiac fibroblasts (CFs) are abundant in the heart and are responsible for cardiac repair post-MI. NF-κB-repressing factor (NKRF) plays a significant role in the transcriptional inhibition of various specific genes. However, the NKRF action mechanism in CFs remains unclear in cardiac repair post-MI. This study investigates the NKRF mechanism in cardiac remodeling and dysfunction post-MI by establishing a CF-specific NKRF-knockout (NKRF-CKO) mouse model. NKRF expression is downregulated in CFs in response to pathological cardiac remodeling in vivo and TNF-α in vitro. NKRF-CKO mice demonstrate worse cardiac function and survival and increased infarct size, heart weight, and MMP2 and MMP9 expression post-MI compared with littermates. NKRF inhibits CF migration and invasion in vitro by downregulating MMP2 and MMP9 expression. Mechanistically, NKRF inhibits human antigen R (HuR) transcription by binding to the classical negative regulatory element within the HuR promoter via an NF-κB-dependent mechanism. This decreases HuR-targeted Mmp2 and Mmp9 mRNA stability. This study suggests that NKRF is a therapeutic target for pathological cardiac remodeling.

Matrix Metalloproteinases Inhibitors in Cancer Treatment: An Updated Review (2013-2023)

Matrix metalloproteinases (MMPs) are identifiable members of proteolytic enzymes that can degrade a wide range of proteins in the extracellular matrix (ECM). MMPs can be categorized into six groups based on their substrate specificity and structural differences: collagenases, gelatinases, stromelysins, matrilysins, metalloelastase, and membrane-type MMPs. MMPs have been linked to a wide variety of biological processes, such as cell transformation and carcinogenesis. Over time, MMPs have been evaluated for their role in cancer progression, migration, and metastasis. Accordingly, various MMPs have become attractive therapeutic targets for anticancer drug development. The first generations of broad-spectrum MMP inhibitors displayed effective inhibitory activities but failed in clinical trials due to poor selectivity. Thanks to the evolution of X-ray crystallography, NMR analysis, and homology modeling studies, it has been possible to characterize the active sites of various MMPs and, consequently, to develop more selective, second-generation MMP inhibitors. In this review, we summarize the computational and synthesis approaches used in the development of MMP inhibitors and their evaluation as potential anticancer agents.

Prognostic role of tissue plasminogen activator in coronary artery disease with or without aortic valve sclerosis

AIMS

We sought to investigate the relationship between circulating tissue plasminogen activator (t-PA) level and long-term outcomes in stable coronary artery disease patients with or without aortic valve sclerosis (AVSc).

METHODS AND RESULTS

Serum levels of t-PA were determined in 347 consecutive stable angina patients with (n = 183) or without (n = 164) AVSc. Outcomes were prospectively recorded as planned clinic evaluations every 6 months up to 7 years. The primary endpoint was a composite of cardiovascular death and rehospitalization due to heart failure. The secondary endpoint included all-cause mortality, cardiovascular death, and rehospitalization due to heart failure. Serum t-PA was significantly higher in AVSc than in non-AVSc patients (2131.22 pg/mL vs. 1495.85 pg/mL, P < 0.001). For patients with AVSc, those with t-PA level above the median (>1840.68 pg/mL) were more likely to meet the primary and secondary endpoints (all P < 0.001). After adjusting for potential confounding factors, serum t-PA level remained significantly predictive for each endpoint in the Cox proportional hazard models. The prognostic value of t-PA was good, with an AUC-ROC of 0.753 (P < 0.001). The combination of t-PA with traditional risk factors improved the risk reclassification of AVSc patients, with a net reclassification index of 0.857 and an integrated discrimination improvement of 0.217 (all P < 0.001). However, for patients without AVSc, both primary and secondary endpoints were similar, irrespective of t-PA levels.

CONCLUSIONS

Elevated circulating t-PA confers an increased risk for poor long-term clinical outcomes in stable coronary artery disease patients with AVSc.

Don't go breakin' my heart: cardioprotective alterations to the mechanical and structural properties of reperfused myocardium during post-infarction inflammation

Myocardial infarctions (MIs) kickstart an intense inflammatory response resulting in extracellular matrix (ECM) degradation, wall thinning, and chamber dilation that leaves the heart susceptible to rupture. Reperfusion therapy is one of the most effective strategies for limiting adverse effects of MIs, but is a challenge to administer in a timely manner. Late reperfusion therapy (LRT; 3 + hours post-MI) does not limit infarct size, but does reduce incidences of post-MI rupture and improves long-term patient outcomes. Foundational studies employing LRT in the mid-twentieth century revealed beneficial reductions in infarct expansion, aneurysm formation, and left ventricle dysfunction. The mechanism by which LRT acts, however, is undefined. Structural analyses, relying largely on one-dimensional estimates of ECM composition, have found few differences in collagen content between LRT and permanently occluded animal models when using homogeneous samples from infarct cores. Uniaxial testing, on the other hand, revealed slight reductions in stiffness early in inflammation, followed soon after by an enhanced resistance to failure for cases of LRT. The use of one-dimensional estimates of ECM organization and gross mechanical function have resulted in a poor understanding of the infarct's spatially variable mechanical and structural anisotropy. To resolve these gaps in literature, future work employing full-field mechanical, structural, and cellular analyses is needed to better define the spatiotemporal post-MI alterations occurring during the inflammatory phase of healing and how they are impacted following reperfusion therapy. In turn, these studies may reveal how LRT affects the likelihood of rupture and inspire novel approaches to guide scar formation.

Matrix Metalloproteinases in Cardioembolic Stroke: From Background to Complications

Matrix metalloproteinases (MMPs) are endopeptidases participating in physiological processes of the brain, maintaining the blood-brain barrier integrity and playing a critical role in cerebral ischemia. In the acute phase of stroke activity, the expression of MMPs increase and is associated with adverse effects, but in the post-stroke phase, MMPs contribute to the process of healing by remodeling tissue lesions. The imbalance between MMPs and their inhibitors results in excessive fibrosis associated with the enhanced risk of atrial fibrillation (AF), which is the main cause of cardioembolic strokes. MMPs activity disturbances were observed in the development of hypertension, diabetes, heart failure and vascular disease enclosed in CHA₂DS₂VASc score, the scale commonly used to evaluate the risk of thromboembolic complications risk in AF patients. MMPs involved in hemorrhagic complications of stroke and activated by reperfusion therapy may also worsen the stroke outcome. In the present review, we briefly summarize the role of MMPs in the ischemic stroke with particular consideration of the cardioembolic stroke and its complications. Moreover, we discuss the genetic background, regulation pathways, clinical risk factors and impact of MMPs on the clinical outcome.

Copper promotes cardiac functional recovery via suppressing the transformation of fibroblasts to myofibroblasts in ischemia-infarcted monkey hearts

Myocardial ischemia leads to cardiac fibrosis along with copper (Cu) loss. Cu repletion diminishes myocardial fibrosis and improves cardiac function. The transformation of fibroblasts to myofibroblasts is highly responsible for the pathogenesis of cardiac fibrosis. This study was undertaken to test the hypothesis that Cu inhibition of cardiac fibrosis results from suppression of myofibroblasts. Rhesus monkeys 4-5 years old were subjected to coronary artery ligation to induce myocardial infarction (MI). At the end of the fourth week after the surgery, an ultrasound-directed Cu-albumin microbubble organ-specific Cu delivery technique was used to treat the ischemia-infarcted monkey hearts twice a week for 4 weeks. This treatment increased Cu concentrations in the infarct area, loosened the collagen cross-linking network, restored blood vessel density, and improved cardiac contractility. Total fibroblasts labeled with vimentin were increased in the infarct area, and Cu repletion did not alter this increase. Myofibroblasts, dually labeled with vimentin and α-smooth muscle actin (α-SMA), were also significantly increased in the infarct area but were significantly reduced by Cu repletion. Correspondingly, the products of myofibroblasts, type I and III collagens and inhibitors of collagenases were significantly reduced. In contrast, metalloproteinase-1 (MMP-1) and MMP-1 producing fibroblasts (vimentin⁺ and MMP-1⁺ cells) were significantly increased. These results suggest that Cu inhibits the transformation of fibroblasts to myofibroblasts, leading to a pro-fibrinolytic switch and an improvement in cardiac function.

Matrix Metalloproteinase 2 and 9 Enzymatic Activities are Selectively Increased in the Myocardium of Chronic Chagas Disease Cardiomyopathy Patients: Role of TIMPs

Chronic Chagas disease (CCC) is an inflammatory dilated cardiomyopathy with a worse prognosis compared to other cardiomyopathies. We show the expression and activity of Matrix Metalloproteinases (MMP) and of their inhibitors TIMP (tissue inhibitor of metalloproteinases) in myocardial samples of end stage CCC, idiopathic dilated cardiomyopathy (DCM) patients, and from organ donors. Our results showed significantly increased mRNA expression of several MMPs, several TIMPs and EMMPRIN in CCC and DCM samples. MMP-2 and TIMP-2 protein levels were significantly elevated in both sample groups, while MMP-9 protein level was exclusively increased in CCC. MMPs 2 and 9 activities were also exclusively increased in CCC. Results suggest that the balance between proteins that inhibit the MMP-2 and 9 is shifted toward their activation. Inflammation-induced increases in MMP-2 and 9 activity and expression associated with imbalanced TIMP regulation could be related to a more extensive heart remodeling and poorer prognosis in CCC patients.

CXCL16 may be a predisposing factor to atherosclerosis: An animal study

Atherosclerosis (AS) is a chronic inflammatory process initiated when lipoprotein is retained in the arterial wall. Leukocyte recruitment accelerates this process. CXC chemokine ligand 16 (CXCL16) acts as a chemokine to attract immune cells and also facilitates the phagocytosis process of modified low‑density lipoprotein. Whether CXCL16 promotes or inhibits the pathological process of AS remains to be elucidated. To clarify this, CXCL16 gene was introduced into C57BL/6J wild‑type mice to establish a stable CXCL16 overexpression mouse model. The initial changes of AS in mice were induced by high‑fat diet (HFD). To study how the interaction of HFD and CXCL16 affected fatty acid metabolism and deposition, body weight and plasma lipid profile were assessed. Soluble CXCL16, matrix metalloproteinase‑9, monocyte chemoattractant protein‑1 and intercellular adhesion molecule‑1 were detected by immunohistochemistry and ELISA to identify how CXCL16 affects AS lesion formation. The present study suggested that overexpression of CXCL16 combined with HFD lead to atherogenesis by upregulating the aforementioned inflammatory related genes at a protein level. The present study was the first, to the best of the authors' knowledge, to build a CXCL16 homozygous transgenic mice model to study how overexpressed CXCL16 is associated with AS for intervening in the occurrence and development of AS.

Elastin-like recombinamers-based hydrogel modulates post-ischemic remodeling in a non-transmural myocardial infarction in sheep

Ischemic heart disease is a leading cause of mortality due to irreversible damage to cardiac muscle. Inspired by the post-ischemic microenvironment, we devised an extracellular matrix (ECM)-mimicking hydrogel using catalyst-free click chemistry covalent bonding between two elastin-like recombinamers (ELRs). The resulting customized hydrogel included functional domains for cell adhesion and protease cleavage sites, sensitive to cleavage by matrix metalloproteases overexpressed after myocardial infarction (MI). The scaffold permitted stromal cell invasion and endothelial cell sprouting in vitro. The incidence of non-transmural infarcts has increased clinically over the past decade, and there is currently no treatment preventing further functional deterioration in the infarcted areas. Here, we have developed a clinically relevant ovine model of non-transmural infarcts induced by multiple suture ligations. Intramyocardial injections of the degradable ELRs-hydrogel led to complete functional recovery of ejection fraction 21 days after the intervention. We observed less fibrosis and more angiogenesis in the ELRs-hydrogel-treated ischemic core region compared to the untreated animals, as validated by the expression, proteomic, glycomic, and histological analyses. These findings were accompanied by enhanced preservation of GATA4⁺ cardiomyocytes in the border zone of the infarct. We propose that our customized ECM favors cardiomyocyte preservation in the border zone by modulating the ischemic core and a marked functional recovery. The functional benefits obtained by the timely injection of the ELRs-hydrogel in a clinically relevant MI model support the potential utility of this treatment for further clinical translation.

Inhibitors of gelatinases (MMP-2 and MMP-9) for the management of hematological malignancies

Matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) are collectively known as gelatinases whereas MMP-2 is gelatinase-A and MMP-9 is termed as gelatinase-B. Gelatinases and other matrix metalloproteinases (MMPs) have long been associated with solid tumor invasion, metastasis and angiogenesis. However, there is paucity of data available regarding the role of gelatinases in hematological malignancies. Recent studies have shown that gelatinases activities or functions are correlated with hematological malignancies. Strategies for designing more specific gelatinase inhibitors like catalytic (CAT) domain inhibitors and hemopexin (PEX) domain inhibitors as well as signaling pathway based or gelatinase expression inhibitors had been reported against hematologic malignant cells. Several substrate based non-selective to non-substrate based relatively selective synthetic matrix metalloproteinase inhibitors (MMPIs) had been developed. Few MMPIs had reached in clinical trials during the period of 1990s-2000s. Unfortunately the anti-tumor and anti-metastatic efficacies of these MMPIs were not justified with patients having several advanced stage solid tumor cancers in any substantial number of clinical trials. Till date not a single MMPI passed phase III clinical trials designed for advanced metastatic cancers due to adverse events as well as lack of ability to show uniformity in disease prolongation. With the best of our knowledge no clinical trial study has been reported with small molecule synthetic inhibitors against hematological malignancies. This review looks at the outcome of clinical trials of MMPIs for advanced stage solid tumors. This can therefore, act as a learning experience for future development of successful gelatinase inhibitors for the management of hematological malignancies.

Mechano-chemo signaling interactions modulate matrix production by cardiac fibroblasts

Extracellular matrix remodeling after myocardial infarction occurs in a dynamic environment in which local mechanical stresses and biochemical signaling species stimulate the accumulation of collagen-rich scar tissue. It is well-known that cardiac fibroblasts regulate post-infarction matrix turnover by secreting matrix proteins, proteases, and protease inhibitors in response to both biochemical stimuli and mechanical stretch, but how these stimuli act together to dictate cellular responses is still unclear. We developed a screen of cardiac fibroblast-secreted proteins in response to combinations of biochemical agonists and cyclic uniaxial stretch in order to elucidate the relationships between stretch, biochemical signaling, and cardiac matrix turnover. We found that stretch significantly synergized with biochemical agonists to inhibit the secretion of matrix metalloproteinases, with stretch either amplifying protease suppression by individual agonists or antagonizing agonist-driven upregulation of protease expression. Stretch also modulated fibroblast sensitivity towards biochemical agonists by either sensitizing cells towards agonists that suppress protease secretion or de-sensitizing cells towards agonists that upregulate protease secretion. These findings suggest that the mechanical environment can significantly alter fibrosis-related signaling in cardiac fibroblasts, suggesting caution when extrapolating in vitro data to predict effects of fibrosis-related cytokines in situations like myocardial infarction where mechanical stretch occurs.

Therapies to prevent post-infarction remodelling: From repair to regeneration

Myocardial infarction is the first cause of worldwide mortality, with an increasing incidence also reported in developing countries. Over the past decades, preclinical research and clinical trials continually tested the efficacy of cellular and acellular-based treatments. However, none of them resulted in a drug or device currently used in combination with either percutaneous coronary intervention or coronary artery bypass graft. Inflammatory, proliferation and remodelling phases follow the ischaemic event in the myocardial tissue. Only recently, single-cell sequencing analyses provided insights into the specific cell populations which determine the final fibrotic deposition in the affected region. In this review, ischaemia, inflammation, fibrosis, angiogenesis, cellular stress and fundamental cellular and molecular components are evaluated as therapeutic targets. Given the emerging evidence of biomaterial-based systems, the increasing use of injectable hydrogels/scaffolds and epicardial patches is reported both as acellular and cellularised/functionalised treatments. Since several variables influence the outcome of any experimented treatment, we return to the pathological basis with an unbiased view towards any specific process or cellular component. Thus, by evaluating the benefits and limitations of the approaches based on these targets, the reader can weigh the rationale of each of the strategies that reached the clinical trials stage. As recent studies focused on the relevance of the extracellular matrix in modulating ischaemic remodelling and enhancing myocardial regeneration, we aim to portray current trends in the field with this review. Finally, approaches towards feasible translational studies that are as yet unexplored are also suggested.

Effect of pore size and spacing on neovascularization of a biodegradble shape memory polymer perivascular wrap

Neointimal hyperplasia (NH) is a main source of failures in arteriovenous fistulas and vascular grafts. Several studies have demonstrated the promise of perivascular wraps to reduce NH via promotion of adventitial neovascularization and providing mechanical support. Limited clinical success thus far may be due to inappropriate material selection (e.g., nondegradable, too stiff) and geometric design (e.g., pore size and spacing, diameter). The influence of pore size and spacing on implant neovascularization is investigated here for a new biodegradable, thermoresponsive shape memory polymer (SMP) perivascular wrap. Following an initial pilot, 21 mice were each implanted with six scaffolds: four candidate SMP macroporous designs (a-d), a nonporous SMP control (e), and microporous GORETEX (f). Mice were sacrificed after 4 (N = 5), 14 (N = 8), and 28 (N = 8) days. There was a statistically significant increase in neovascularization score between all macroporous groups compared to nonporous SMP (p < .023) and microporous GORETEX (p < .007) controls at Day 28. Wider-spaced, smaller-sized pore designs (223 μm-spaced, 640 μm-diameter Design c) induced the most robust angiogenic response, with greater microvessel number (p < .0114) and area (p < .0055) than nonporous SMPs and GORETEX at Day 28. This design also produced significantly greater microvessel density than nonporous SMPs (p = 0.0028) and a smaller-spaced, larger-sized pore (155 μm-spaced, 1,180 μm-sized Design b) design (p = .0013). Strong neovascularization is expected to reduce NH, motivating further investigation of this SMP wrap with controlled pore spacing and size in more advanced arteriovenous models.

Expression of matrix metalloproteinases and their inhibitors at the implantation site in ampullary ectopic pregnancies

OBJECTIVE

This study investigated the qualitative and semi-quantitative expression of metalloproteinases (MMP) and their tissue inhibitors (TIMP) in trophoblastic tissue during ampullary ectopic pregnancies and correlated that expression with the degree of tubal invasion.

STUDY DESIGN

It is a prospective study that included 34 patients diagnosed with ampullary tubal pregnancy who underwent salpingectomy. A histological evaluation of the depth of trophoblastic invasion in the tubes obtained was performed. Subsequently, the expression of the MMP-2, MMP-9, MMP-14, TIMP-1, TIMP-2 and TIMP-3 markers was qualitatively and semi-quantitatively evaluated by indirect immunohistochemistry. In addition, the degree of trophoblastic invasion was correlated with the expression of each marker and with the metalloproteinase/inhibitor ratios.

RESULTS

MMP-2 (11.2 %; 3.6-17.9) was the marker with greater expression at the implantation site, both in the qualitative and semi-quantitative assessment, while MMP-9 (2.23 %; 0.2-5.4) and TIMP-3 (2.53 %; 0.1-15.3) were only weakly expressed.

CONCLUSION

There was wide variation in expression among the markers and metalloproteinase/inhibitor ratios studied compared to the degrees of invasion.

Cell type-specific microRNA therapies for myocardial infarction

Current interventions fail to recover injured myocardium after infarction and prompt the need for development of cardioprotective strategies. Of increasing interest is the therapeutic use of microRNAs to control gene expression through specific targeting of mRNAs. In this Review, we discuss current microRNA-based therapeutic strategies, describing the outcomes and limitations of key microRNAs with a focus on target cell types and molecular pathways. Last, we offer a perspective on the outlook of microRNA therapies for myocardial infarction, highlighting the outstanding challenges and emerging strategies.

The regulation of trophoblast invasion and decidual reaction by matrix metalloproteinase-2, metalloproteinase-7, and metalloproteinase-9 expressions in the rat endometrium

PURPOSE

We aimed to evaluate how matrix metalloproteinases (MMPs) regulate the trophoblast invasion and placentation.

METHODS

Female rats were divided into the estrous cycle and early pregnancy day groups. Obtained uterine tissues and implantation sites were processed for immunofluorescence and real-time PCR examinations.

RESULTS

The mRNA expression of MMP-7 was higher than MMP-2 and MMP-9. Immunofluorescence findings confirmed that MMP-2, MMP-7, and MMP-9 were localized in the endometrial stroma, while MMP-7 was high in glandular and lining epithelial cells throughout the entire estrous cycle. However, their immunolocalizations and mRNA expressions were dramatically changed with the early pregnancy days. The MMP-7 reached very strong immunostaining in the giant trophoblast cells (GTCs), and the cytoplasm of mature and differentiating decidual cells, whereas MMP-2 and MMP-9 were mostly seen in the primary decidual zone (PDZ), GTCs, and the endothelium of blood vessels.

CONCLUSIONS

All three MMPs seemed likely to be a key mediator of trophoblast invasion into the decidual region as well as angiogenesis during the placentation process. Due to the strong and wide expression of MMP-7 in the mature decidua, it could be suggested that MMP-7 is important for decidual ECM remodeling and it might be used as a new marker of decidual reaction.

Large Animal Models of Cell-Free Cardiac Regeneration

The adult mammalian heart lacks the ability to sufficiently regenerate itself, leading to the progressive deterioration of function and heart failure after ischemic injuries such as myocardial infarction. Thus far, cell-based therapies have delivered unsatisfactory results, prompting the search for cell-free alternatives that can induce the heart to repair itself through cardiomyocyte proliferation, angiogenesis, and advantageous remodeling. Large animal models are an invaluable step toward translating basic research into clinical applications. In this review, we give an overview of the state-of-the-art in cell-free cardiac regeneration therapies that have been tested in large animal models, mainly pigs. Cell-free cardiac regeneration therapies involve stem cell secretome- and extracellular vesicles (including exosomes)-induced cardiac repair, RNA-based therapies, mainly regarding microRNAs, but also modified mRNA (modRNA) as well as other molecules including growth factors and extracellular matrix components. Various methods for the delivery of regenerative substances are used, including adenoviral vectors (AAVs), microencapsulation, and microparticles. Physical stimulation methods and direct cardiac reprogramming approaches are also discussed.

Targeted Injection of a Truncated Form of Tissue Inhibitor of Metalloproteinase 3 Alters Post-Myocardial Infarction Remodeling

Infarct expansion can occur after myocardial infarction (MI), which leads to adverse left ventricular (LV) remodeling and failure. An imbalance between matrix metalloproteinase (MMP) induction and tissue inhibitors of MMPs (TIMPs) can accelerate this process. Past studies have shown different biologic effects of TIMP-3, which may depend upon specific domains within the TIMP-3 molecule. This study tested the hypothesis that differential effects of direct myocardial injections of either a full-length recombinant TIMP-3 (F-TIMP-3) or a truncated form encompassing the N-terminal region (N-TIMP-3) could be identified post-MI. MI was induced in pigs that were randomized for MI injections (30 mg) and received targeted injections within the MI region of F-TIMP-3 (n = 8), N-TIMP-3 (n = 9), or saline injection (MI-only, n = 11). At 14 days post-MI, LV ejection fraction fell post-MI but remained higher in both TIMP-3 groups. Tumor necrosis factor and interleukin-10 mRNA increased by over 10-fold in the MI-only and N-TIMP-3 groups but were reduced with F-TIMP-3 at this post-MI time point. Direct MI injection of either a full-length or truncated form of TIMP-3 is sufficient to favorably alter the course of post-MI remodeling. The functional and differential relevance of TIMP-3 domains has been established in vivo since the TIMP-3 constructs demonstrated different MMP/cytokine expression profiles. These translational studies identify a unique and more specific therapeutic strategy to alter the course of LV remodeling and dysfunction after MI. SIGNIFICANCE STATEMENT: Using different formulations of tissue inhibitor of matrix metalloproteinase-3 (TIMP-3), when injected into the myocardial infarction (MI) region, slowed the progression of indices of left ventricular (LV) failure, suggesting that the N terminus of TIMP-3 is sufficient to attenuate early adverse functional events post-MI. Injections of full-length recombinant TIMP-3, but not of the N-terminal region of TIMP-3, reduced relative indices of inflammation at the mRNA level, suggesting that the C-terminal region affects other biological pathways. These unique proof-of-concept studies demonstrate the feasibility of using recombinant small molecules to selectively interrupt adverse LV remodeling post-MI.

Expression of ectopic trypsin in atherosclerotic plaques and the effects of aprotinin on plaque stability

BACKGROUND

Our previous research revealed that trypsin is abundantly expressed in atherosclerotic plaques and its distribution overlaps with that of matrix metalloproteinase-9 (MMP-9). This study was performed to explore the possible roles of trypsin in vulnerable atherosclerotic plaque formation.

METHODS AND RESULTS

Twenty-four rabbits were randomly assigned to a normal (control) group, an atherosclerosis (experimental) group and a trypsin inhibitor (aprotinin) group. In the 13th feeding week, the aprotinin group was treated with 5 mg/kg/day aprotinin via ear vein for 4 weeks. At the end of the 16th week, coronary arterial and aortic expression of trypsin, proteinase-activated receptor-2 (PAR-2), activated MMP-9, and pro-inflammatory cytokines were significantly greater in the experimental group than in the control group. Aprotinin decreased trypsin expression and activation in plaques, blocked PAR-2 and MMP-9 activation, and decreased cytokine expression; it also increased fibrous cap thickness, decreased the intima-media thickness and intimal/medial ratio, thus significantly ameliorating plaque vulnerability. Upregulated trypsin, MMP-9 and PAR-2 were also found in coronary intimal atherosclerotic plaques of patients undergoing coronary artery bypass grafting.

CONCLUSIONS

Ectopic trypsin was significantly upregulated in atherosclerotic plaques, which increased pro-inflammatory cytokine levels by activating PAR-2 and promoted plaque instability by activating proMMP-9, thereby promoting atherosclerosis and plaque vulnerability. In addition, the high trypsin expression in human coronary intimal atherosclerotic plaques suggests that targeting trypsin may be a new strategy for acute coronary syndrome prevention.

Cardioprotective Effects of Metalloproteinase Inhibitor 1-({4-[(4-Chlorobenzoyl)amino]phenyl}sulfonyl-L-Proline in Modeled Acute Myocardial Infarction

Cardioprotective effect of 1-({4 [(4 chlorobenzoyl)amino]phenyl}sulfonyl-L-proline (compound AL-828) was studied in rats with modeled acute myocardial infarction. The test compound was administered intragastrically in a dose of 30 mg/kg/day for 3 days prior to infarction modeling. Metalloproteinase inhibitor antibiotic doxycycline served as the reference drug and was administered in a dose of 40 mg/kg/day by the same schedule. It was shown that AL-828 similar to doxycycline significantly reduced the intensity of myocardial remodeling and maintained the inotropic function of the myocardium in the acute phase of myocardial infarction. By the 20th minute of ischemia, the end-systolic dimension of the left ventricle in control animals increased from 1.98±0.12 to 3.84±0.16 mm, while in animals treated with AL-828, this increase was significantly (p=0.007) less pronounced (from 1.84±0.07 and 2.87±0.21 mm, respectively). The ejection fraction characterizing the inotropic status of the left ventricle in animals treated with AL-828 was significantly higher (p=0.02). By its cardioprotective activity, AL-828 was not inferior to the reference drug doxycycline. It can be assumed that the cardioprotective activity of compound AL-828 is related to suppression of MMP-9 expression and/or inhibition of its activity as was previously demonstrated by us.

Regulation of Myocardial Extracellular Matrix Dynamic Changes in Myocardial Infarction and Postinfarct Remodeling

The article represents literature review dedicated to molecular and cellular mechanisms underlying clinical manifestations and outcomes of acute myocardial infarction. Extracellular matrix adaptive changes are described in detail as one of the most important factors contributing to healing of damaged myocardium and post-infarction cardiac remodeling. Extracellular matrix is reviewed as dynamic constantly remodeling structure that plays a pivotal role in myocardial repair. The role of matrix metalloproteinases and their tissue inhibitors in fragmentation and degradation of extracellular matrix as well as in myocardium healing is discussed. This review provides current information about fibroblasts activity, the role of growth factors, particularly transforming growth factor β and cardiotrophin-1, colony-stimulating factors, adipokines and gastrointestinal hormones, various matricellular proteins. In conclusion considering the fact that dynamic transformation of extracellular matrix after myocardial ischemic damage plays a pivotal role in myocardial infarction outcomes and prognosis, we suggest a high importance of further investigation of mechanisms underlying extracellular matrix remodeling and cell-matrix interactions in cardiovascular diseases.

TSLP promote M2 macrophages polarization and cardiac healing after myocardial infarction

Macrophages play an important role in inflammation and cardiac remodeling in response to myocardial infarction (MI). Earlier shift of inflammtory M1 macrophages to reparative M2 macrophages has demonstrated significant improvements in MI wound modeling and cardiac function. Here, we reported that TSLP could promote M1 to M2 macrophage polarization, and AngII skewed the macrophage phenotype towards M2 by inducing TSLP expression in vitro. Meanwhile, AngII could inhibit the expression of MMP2 and MMP9 in macrophages, which are engaged in ECM degradation and cardiac remodeling. In post-MI mice, TSLP expression were up-regulated in cardiac tissue and serum, probably induced by renin-angiotensin system activation and AngII level up-regulation following MI. Our study mapped the continuum of changes that occured in cardiac macrophages over the first week of MI, and found that rTSLP treatment promoted earlier phenotype shift of M1 to M2 macrophages, improving cardiac healing and ventricular function recovery. Taken together, this work identified a very promising therapeutic opportunity to manage macrophage phenotype and enhance resolution of inflammation in the post-MI heart.

Developing an Antibody-Drug Conjugate Approach to Selective Inhibition of an Extracellular Protein

Antibody-drug conjugates (ADCs) are a growing class of therapeutics that harness the specificity of antibodies and the cell-killing potency of small-molecule drugs. Beyond cytotoxics, there are few examples of the application of an ADC approach to difficult drug discovery targets. Here, we present the initial development of a non-internalising ADC, with a view to selectively inhibiting an extracellular protein. Employing the wellinvestigated matrix metalloproteinase-9 (MMP-9) as our model, we adapted a broad-spectrum, nonselective MMP inhibitor for conjugation and linked this to a MMP-9-targeting antibody. The resulting ADC fully inhibits MMP-9, and ELISA results suggest antibody targeting can direct a nonselective inhibitor.

Glycoproteomic Profiling Provides Candidate Myocardial Infarction Predictors of Later Progression to Heart Failure

We hypothesized that identifying plasma glycoproteins that predict the development of heart failure following myocardial infarction (MI) could help to stratify subjects at risk. Plasma collected at visit 2 (2005-2008) from an MI subset of Jackson Heart Study participants underwent glycoproteomics and was grouped by the outcome: (1) heart failure hospitalization after visit 2 (n = 15) and (2) without hospitalization by 2012 (n = 45). Proteins were mapped for biological processes and functional pathways using Ingenuity Pathway Analysis and linked to clinical characteristics. A total of 198 glycopeptides corresponding to 88 proteins were identified (data available via ProteomeXchange with identifier PXD009870). Of these, 14 glycopeptides were significantly different between MI and MI + HF groups and corresponded to apolipoprotein (Apo) F, transthyretin, Apo C-IV, prostaglandin-D2 synthase, complement C9, and CD59 (p < 0.05 for all). All proteins were elevated in the MI + HF group, except CD59, which was lower. Four canonical pathways were upregulated in the MI + HF group (p < 0.05 for all): acute phase response, liver X receptor/retinoid X receptor, and macrophage reactive oxygen species generation. The coagulation pathway was significantly downregulated in the MI + HF group (p < 0.05). Even after adjustment for age and sex, Apo F was associated with the increased risk for heart failure (OR = 21.84; 95% CI 3.20-149.14). In conclusion, glycoproteomic profiling provided candidate early MI predictors of later progression to heart failure.

Post-infarct morphine treatment mitigates left ventricular remodeling and dysfunction in a rat model of ischemia-reperfusion

Following myocardial infarction, the heart undergoes a series of dramatic compensations which may later form a maladaptive picture characterized by ventricular dilation and pump failure. Among several opioid agents, morphine has been shown to confer protection against reperfusion injury and infarct size. Here, we sought to study the cardioprotective effect of post-infarct morphine treatment against left ventricular adverse remodeling. We induced myocardial infarction in male Sprague - Dawley rats by ligating left anterior descending artery and then, treated these animals with three different doses of morphine -0.3, 3 and 10 mg/kg (i.p.). The echocardiographic evaluation depicted improved cardiac performance and lesser chamber dilation in the animals that had received 3 mg/kg of morphine. Next, we studied the effect of 3 mg/kg morphine administration on left ventricular hemodynamics, infarct size, tissue architecture, changes in lung and heart weight, circulating TNF-α level and post-MI mRNA expression of collagen-1, collagen-3, TGF-β, TNF-α, MMP-2 and MMP-9. Five-day morphine administration markedly improved LV function, and also reduced infarct size, myocyte hypertrophy, fibrosis, index of infarct expansion, heart weight and serum TNF-α level. Moreover, morphine alleviated MI-induced increase in wet and dry lung weight. Morphine also altered the mRNA expression of fibrosis-related genes, TNF-α, MMP-2 and MMP-9. In conclusion, post-infarct morphine treatment can mitigate adverse remodeling and cardiac dysfunction after MI. Beside analgesic effect, we may be able to harvest benefits from the antifibrotic and anti-remodeling action of morphine in patients with the acute coronary syndrome.

Extracellular matrix roles in cardiorenal fibrosis: Potential therapeutic targets for CVD and CKD in the elderly

Whereas hypertension, diabetes, and dyslipidemia are age-related risk factors for cardiovascular disease (CVD) and chronic kidney disease (CKD), aging alone is an independent risk factor. With advancing age, the heart and kidney gradually but significantly undergo inflammation and subsequent fibrosis, which eventually results in an irreversible decline in organ physiology. Through cardiorenal network interactions, cardiac dysfunction leads to and responds to renal injury, and both facilitate aging effects. Thus, a comprehensive strategy is needed to evaluate the cardiorenal aging network. Common hallmarks shared across systems include extracellular matrix (ECM) accumulation, along with upregulation of matrix metalloproteinases (MMPs) including MMP-9. The wide range of MMP-9 substrates, including ECM components and inflammatory cytokines, implicates MMP-9 in a variety of pathological and age-related processes. In particular, there is strong evidence that inflammatory cell-derived MMP-9 exacerbates cardiorenal aging. This review explores the potential therapeutic targets against CVD and CKD in the elderly, focusing on ECM and MMP roles.

Utility of Glycosylated TIMP3 molecules: Inhibition of MMPs and TACE to improve cardiac function in rat myocardial infarct model

Tissue Inhibitor of Metalloproteinase 3 (TIMP3) is a secreted protein that has a great utility to inhibit elevated metalloproteinase (MMP) activity in injured tissues including infarcted cardiac tissue, inflamed vessels, and joint cartilages. An imbalance between TIMP3 and active MMP levels in the local tissue area may cause worsening of disease progression. To counter balance elevated MMP levels, exogenous administration of TIMP3 appeared to be beneficial in preclinical studies. However, the current form of WT-TIMP3 molecule has a limitation to be a therapeutic candidate due to low production yield, short plasma half-life, injection site retention, and difficulty in delivery, etc. We have engineered TIMP3 molecules by adding extra glycosylation sites or fusing with albumin, Fc, and antibody to improve pharmacokinetic properties. In general, the C-terminal fusion of TIMP3 improved expression and production in mammalian cells and extended half-lives dramatically 5-20 folds. Of note, a site-specific glycosylation at K22S/F34N resulted in a higher level of expression and better cardiac function compared to other fusion proteins in the context of left ventricle ejection fraction (LVEF) changes in a rat myocardial infarction model. It appeared that cardiac efficacy depends on a high ECM binding affinity, in which K22S/F34N and N-TIMP3 showed a higher binding to the ECM compared to other engineered molecules. In conclusion, we found that the ECM binding and sustained residence of injected TIMP3 molecules are important for cardiac tissue localization and inhibition of adverse remodeling activity.

White Wine Consumption Influences Inflammatory Phase of Repair After Myocardial Infarction in Rats

Effects of white wine (WW) consumption on the expression of inflammatory markers/mediators (MMP-2, MMP-9, NF-ĸB p65 and TGF-β1) in myocardial tissue after experimentally induced permanent myocardial ischemia was investigated. Male Sprague-Dawley rats were given either a combination of WW and water or only water, for 28 days. After coronary ligation, animals were left to survive for 24 hours. Three representative areas: infarct/ischemic, peri-infarct/border zone, and control/non-ischemic zones were analyzed for expression of immunoreactivity by measuring the threshold area % of signal density. For MMP-9, significantly smaller expression was found in all 3 zones of wine drinking animals (P < 0.001). There was no difference in MMP-2 immunoreactivity between the 2 groups, except in peri-infarct zones, where the signal was significantly decreased (P < 0.001). The same pattern of expression was found for the NF-κB p65 signal, although no differences between experimental groups were observed for TGF-β1. White wine consumption decreases the expression of the 3 investigated inflammatory markers/mediators in the peri-infarct zone, suggesting its significant modulatory effect. For MMP-9 and MMP-2, expression was similar to the effect of postischemic reperfusion. No effect on TGF-β1 was observed, highlighting its role in being the master-switch, changing from the inflammatory to the proliferative stage of infarct healing.

HDAC inhibition helps post-MI healing by modulating macrophage polarization

AIMS

Following an acute myocardial infarction (MI) the extracellular matrix (ECM) undergoes remodeling in order to prevent dilation of the infarct area and maintain cardiac output. Excessive and prolonged inflammation following an MI exacerbates adverse ventricular remodeling. Macrophages are an integral part of the inflammatory response that contribute to this remodeling. Treatment with histone deacetylase (HDAC) inhibitors preserves LV function and myocardial remodeling in the post-MI heart. This study tested whether inhibition of HDAC activity resulted in preserving post-MI LV function through the regulation of macrophage phenotype and early resolution of inflammation.

METHODS AND RESULTS

HDAC inhibition does not affect the recruitment of CD45⁺ leukocytes, CD45⁺/CD11b⁺ inflammatory monocytes or CD45⁺/CD11b⁺CD86⁺ inflammatory macrophages for the first 3 days following infarct. Further, HDAC inhibition does not change the high expression level of the inflammatory cytokines in the first days following MI. However, by day 7, there was a significant reduction in the levels of CD45⁺/Cd11b⁺ and CD45⁺/CD11b⁺/CD86⁺ cells with HDAC inhibition. Remarkably, HDAC inhibition resulted in the dramatic increase in the recruitment of CD45⁺/CD11b⁺/CD206⁺ alternatively activated macrophages as early as 1 day which remained significantly elevated until 5 days post-MI. qRT-PCR revealed that HDAC inhibitor treatment shifts the cytokine and chemokine environment towards an M2 phenotype with upregulation of M2 markers at 1 and 5 days post-MI. Importantly, HDAC inhibition correlates with significant preservation of both LV ejection fraction and end-diastolic volume and is associated with a significant increase in micro-vessel density in the border zone at 14 days post-MI.

CONCLUSION

Inhibition of HDAC activity result in the early recruitment of reparative CD45⁺/CD11b⁺/CD206⁺ macrophages in the post-MI heart and correlates with improved ventricular function and remodeling. This work identifies a very promising therapeutic opportunity to manage macrophage phenotype and enhance resolution of inflammation in the post-MI heart.

Myocardial infarction remodeling that progresses to heart failure: a signaling misunderstanding

After myocardial infarction, remodeling of the left ventricle involves a wound-healing orchestra involving a variety of cell types. In order for wound healing to be optimal, appropriate communication must occur; these cells all need to come in at the right time, be activated at the right time in the right amount, and know when to exit at the right time. When this occurs, a new homeostasis is obtained within the infarct, such that infarct scar size and quality are sufficient to maintain left ventricular size and shape. The ideal scenario does not always occur in reality. Often, miscommunication can occur between infarct and remote spaces, across the temporal wound-healing spectrum, and across organs. When miscommunication occurs, adverse remodeling can progress to heart failure. This review discusses current knowledge gaps and recent development of the roles of inflammation and the extracellular matrix in myocardial infarction remodeling. In particular, the macrophage is one cell type that provides direct and indirect regulation of both the inflammatory and scar-forming responses. We summarize current research efforts focused on identifying biomarker indicators that reflect the status of each component of the wound-healing process to better predict outcomes.

The Role of Cardiokines in Heart Diseases: Beneficial or Detrimental?

Cardiovascular disease remains the leading cause of morbidity and mortality, imposing a major disease burden worldwide. Therefore, there is an urgent need to identify new therapeutic targets. Recently, the concept that the heart acts as a secretory organ has attracted increasing attention. Proteins secreted by the heart are called cardiokines, and they play a critical physiological role in maintaining heart homeostasis or responding to myocardial damage and thereby influence the development of heart diseases. Given the critical role of cardiokines in heart disease, they might represent a promising therapeutic target. This review will focus on several cardiokines and discuss their roles in the pathogenesis of heart diseases and as potential therapeutics.

The multifaceted link between inflammation and human diseases

Increasing reports on epidemiological, diagnostic, and clinical studies suggest that dysfunction of the inflammatory reaction results in chronic illnesses such as cancer, arthritis, arteriosclerosis, neurological disorders, liver diseases, and renal disorders. Chronic inflammation might progress if injurious agent persists; however, more typically than not, the response is chronic from the start. Distinct to most changes in acute inflammation, chronic inflammation is characterized by the infiltration of damaged tissue by mononuclear cells like macrophages, lymphocytes, and plasma cells, in addition to tissue destruction and attempts to repair. Phagocytes are the key players in the chronic inflammatory response. However, the important drawback is the activation of pathological phagocytes, which might result from continued tissue damage and lead to harmful diseases. The longer the inflammation persists, the greater the chance for the establishment of human diseases. The aim of this review was to focus on advances in the understanding of chronic inflammation and to summarize the impact and involvement of inflammatory agents in certain human diseases.

Cardioprotection and thyroid hormones

The evolution of cardiac disease after an acute ischemic event depends on a complex and dynamic network of mechanisms alternating from ischemic damage due to acute coronary occlusion to reperfusion injury due to the adverse effects of coronary revascularization till post-ischemic remodeling. Cardioprotection is a new purpose of the therapeutic interventions in cardiology with the goal to reduce infarct size and thus prevent the progression toward heart failure after an acute ischemic event. In a complex biological system such as the human one, an effective cardioprotective strategy should diachronically target the network of cross-talking pathways underlying the disease progression. Thyroid system is strictly interconnected with heart homeostasis, and recent studies highlighted its role in cardioprotection, in particular through the preservation of mitochondrial function and morphology, the antifibrotic and proangiogenetic effect and also to the potential induction of cell regeneration and growth. The objective of this review was to highlight the cardioprotective role of triiodothyronine in the complexity of post-ischemic disease evolution.

Extracellular matrix remodeling and cardiac fibrosis

Cardiac fibrosis, characterized by excessive deposition of extracellular matrix (ECM) proteins in the myocardium, distorts the architecture of the myocardium, facilitates the progression of arrhythmia and cardiac dysfunction, and influences the clinical course and outcome in patients with heart failure. This review describes the composition and homeostasis in normal cardiac interstitial matrix and introduces cellular and molecular mechanisms involved in cardiac fibrosis. We also characterize the ECM alteration in the fibrotic response under diverse cardiac pathological conditions and depict the role of matricellular proteins in the pathogenesis of cardiac fibrosis. Moreover, the diagnosis of cardiac fibrosis based on imaging and biomarker detection and the therapeutic strategies are addressed. Understanding the comprehensive molecules and pathways involved in ECM homeostasis and remodeling may provide important novel potential targets for preventing and treating cardiac fibrosis.

Proteomic analysis of the cardiac extracellular matrix: clinical research applications

INTRODUCTION

The cardiac extracellular matrix (ECM) provides anatomical, biochemical, and physiological support to the left ventricle. ECM proteins are difficult to detect using unbiased proteomic approaches due to solubility issues and a relatively low abundance compared to cytoplasmic and mitochondrial proteins present in highly prevalent cardiomyocytes. Areas covered: Proteomic capabilities have dramatically improved over the past 20 years, due to enhanced sample preparation protocols and increased capabilities in mass spectrometry (MS), database searching, and bioinformatics analysis. This review summarizes technological advancements made in proteomic applications that make ECM proteomics highly feasible. Expert commentary: Proteomic analysis of the ECM provides an important contribution to our understanding of the molecular and cellular processes associated with cardiovascular disease. Using results generated from proteomics approaches in basic science applications and integrating proteomics templates into clinical research protocols will aid in efforts to personalize medicine.

Densification of Type I Collagen Matrices as a Model for Cardiac Fibrosis

Cardiac fibrosis is a disease state characterized by excessive collagenous matrix accumulation within the myocardium that can lead to ventricular dilation and systolic failure. Current treatment options are severely lacking due in part to the poor understanding of the complexity of molecular pathways involved in cardiac fibrosis. To close this gap, in vitro model systems that recapitulate the defining features of the fibrotic cellular environment are in need. Type I collagen, a major cardiac extracellular matrix protein and the defining component of fibrotic depositions, is an attractive choice for a fibrosis model, but demonstrates poor mechanical strength due to solubility limits. However, plastic compression of collagen matrices is shown to significantly increase its mechanical properties. Here, confined compression of oligomeric, type I collagen matrices is utilized to resemble defining hallmarks seen in fibrotic tissue such as increased collagen content, fibril thickness, and bulk compressive modulus. Cardiomyocytes seeded on compressed matrices show a strong beating abrogation as observed in cardiac fibrosis. Gene expression analysis of selected fibrosis markers indicates fibrotic activation and cardiomyocyte maturation with regard to the existing literature. With these results, a promising first step toward a facile heart-on-chip model is presented to study cardiac fibrosis.

Intracoronary delivery of recombinant TIMP-3 after myocardial infarction: effects on myocardial remodeling and function

Ischemia-reperfusion (IR) and myocardial infarction (MI) cause adverse left ventricular (LV) remodeling and heart failure and are facilitated by an imbalance in matrix metalloproteinase (MMP) activation and the endogenous tissue inhibitors of metalloproteinase (TIMPs). We have identified that myocardial injections of recombinant TIMP-3 (rTIMP-3; human full length) can interrupt post-MI remodeling. However, whether and to what degree intracoronary delivery of rTIMP-3 post-IR is feasible and effective remained to be established. Pigs (25 kg) underwent coronary catheterization and balloon occlusion of the left anterior descending coronary artery (LAD) for 90 min whereby at the final 4 min, rTIMP-3 (30 mg, n = 9) or saline was infused in the distal LAD. LV echocardiography was performed at 3-28 days post-IR, and LV ejection fraction (EF) and LV end-diastolic volume were measured. LV EF fell and LV end-diastolic volume increased from baseline (pre-IR) values (66 ± 1% and 40 ± 1 ml, respectively, means ± standard deviation) in both groups; however, the extent of LV dilation was reduced in the rTIMP-3 group by 40% at 28 days post-IR (P < 0.05) and the fall in LV EF was attenuated. Despite equivalent plasma troponin levels (14 ± 3 ng/ml), computed MI size at 28 days was reduced by over 45% in the rTIMP-3 group (P < 0.05), indicating that rTIMP-3 treatment abrogated MI expansion post-IR. Plasma NH2-terminal pro-brain natriuretic peptide levels, an index of heart failure progression, were reduced by 25% in the rTIMP-3 group compared with MI saline values (P < 0.05). Although the imbalance between MMPs and TIMPs has been recognized as a contributory factor for post-MI remodeling, therapeutic strategies targeting this imbalance have not been forthcoming. This study is the first to demonstrate that a relevant delivery approach (intracoronary) using rTIMP can alter the course of post-MI remodeling.NEW & NOTEWORTHY Myocardial ischemia and reperfusion injury remain significant causes of morbidity and mortality whereby alterations in the balance between matrix metalloproteinase and tissue inhibitor of metalloproteinase have been identified as contributory biological mechanisms. This novel translational study advances the concept of targeted delivery of recombinant proteins to modify adverse myocardial remodeling in ischemia-reperfusion injury.

Reperfusion therapy-What's with the obstructed, leaky and broken capillaries?

Microvascular dysfunction is well established as an early and rate-determining factor in the injury response of tissues to ischemia and reperfusion (I/R). Severe endothelial cell dysfunction, which can develop without obvious morphological cell injury, is a major underlying cause of the microvascular abnormalities that accompany I/R. While I/R-induced microvascular dysfunction is manifested in different ways, two responses that have received much attention in both the experimental and clinical setting are impaired capillary perfusion (no-reflow) and endothelial barrier failure with a transition to hemorrhage. These responses are emerging as potentially important determinants of the severity of the tissue injury response, and there is growing clinical evidence that they are predictive of clinical outcome following reperfusion therapy. This review provides a summary of animal studies that have focused on the mechanisms that may underlie the genesis of no-reflow and hemorrhage following reperfusion of ischemic tissues, and addresses the clinical evidence that implicates these vascular events in the responses of the ischemic brain (stroke) and heart (myocardial infarction) to reperfusion therapy. Inasmuch as reactive oxygen species (ROS) and matrix metalloproteinases (MMP) are frequently invoked as triggers of the microvascular dysfunction elicited by I/R, the potential roles and sources of these mediators are also discussed. The available evidence in the literature justifies the increased interest in the development of no-reflow and hemorrhage in heart and brain following reperfusion therapy, and suggests that these vascular events may be predictive of poor clinical outcome and warrant the development of targeted treatment strategies.

Clinical Implications of Compounds Designed to Inhibit ECM-Modifying Metalloproteinases

Remodeling of the extracellular matrix (ECM) is crucial in development and homeostasis, but also has a significant role in disease progression. Two metalloproteinase families, the matrix metalloproteinases (MMPs) and a disintegrin and metalloproteases (ADAMs), participate in the remodeling of the ECM, either directly or through the liberation of growth factors and cell surface receptors. The correlation of MMP and ADAM activity to a variety of diseases has instigated numerous drug development programs. However, broad-based and Zn²⁺ -chelating MMP and ADAM inhibitors have fared poorly in the clinic. Selective MMP and ADAM inhibitors have been described recently based on (a) antibodies or antibody fragments or (b) small molecules designed to take advantage of protease secondary binding sites (exosites) or allosteric sites. Clinical trials have been undertaken with several of these inhibitors, while others are in advanced pre-clinical stages.