Matrix metalloproteinases and diabetic vascular complications

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.

Therapeutic strategy of biological macromolecules based natural bioactive compounds of diabetes mellitus and future perspectives: A systematic review

High blood glucose levels are a hallmark of the metabolic syndrome known as diabetes mellitus. More than 600 million people will have diabetes by 2045 as the global prevalence of the disease continues to rise. Contemporary antidiabetic drugs reduce hyperglycemia and its consequences. However, these drugs come with undesirable side effects, so it's encouraging that research into plant extracts and bioactive substances with antidiabetic characteristics is on the rise. Natural remedies are preferable to conventional anti-diabetic drugs since they are safer for the body, more affordable and have fewer potential adverse effects. Biological macromolecules such as liposomes, niosomes, polymeric nanoparticles, solid lipid nanoparticles, nanoemulsions and metallic nanoparticles are explored in this review. Current drug restrictions have been addressed, and the effectiveness of plant-based antidiabetic therapies has enhanced the merits of these methods. Plant extracts' loading capacity and the carriers' stability are the primary obstacles in developing plant-based nanocarriers. Hydrophilic, hydrophobic, and amphiphilic drugs are covered, and a brief overview of the amphipathic features of liposomes, phospholipids, and lipid nanocarriers is provided. Metallic nanoparticles' benefits and attendant risks are highlighted to emphasize their efficiency in treating hyperglycemia. Researchers interested in the potential of nanoparticles loaded with plant extracts as antidiabetic therapeutics may find the current helpful review.

The Pathophysiology of Collateral Circulation in Acute Ischemic Stroke

Cerebral collateral circulation is a network of blood vessels which stabilizes blood flow and maintains cerebral perfusion whenever the main arteries fail to provide an adequate blood supply, as happens in ischemic stroke. These arterial networks are able to divert blood flow to hypoperfused cerebral areas. The extent of the collateral circulation determines the volume of the salvageable tissue, the so-called "penumbra". Clinically, this is associated with greater efficacy of reperfusion therapies (thrombolysis and thrombectomy) in terms of better short- and long-term functional outcomes, lower incidence of hemorrhagic transformation and of malignant oedema, and smaller cerebral infarctions. Recent advancements in brain imaging techniques (CT and MRI) allow us to study these anastomotic networks in detail and increase the likelihood of making effective therapeutic choices. In this narrative review we will investigate the pathophysiology, the clinical aspects, and the possible diagnostic and therapeutic role of collateral circulation in acute ischemic stroke.

Extracellular Matrix Expression in Human Pancreatic Fat Cells of Patients with Normal Glucose Regulation, Prediabetes and Type 2 Diabetes

Previously, we found that human pancreatic preadipocytes (PPAs) and islets influence each other and that the crosstalk with the fatty liver via the hepatokine fetuin-A/palmitate induces inflammatory responses. Here, we examined whether the mRNA-expression of pancreatic extracellular matrix (ECM)-forming and -degrading components differ in PPAs from individuals with normal glucose regulation (PPAs-NGR), prediabetes (PPAs-PD), and type 2 diabetes (PPAs-T2D), and whether fetuin-A/palmitate impacts ECM-formation/degradation and associated monocyte invasion. Human pancreatic resections were analyzed (immuno)histologically. PPAs were studied for mRNA expression by real-time PCR and protein secretion by Luminex analysis. Furthermore, co-cultures with human islets and monocyte migration assays in Transwell plates were conducted. We found that in comparison with NGR-PPAs, TIMP-2 mRNA levels were lower in PPAs-PD, and TGF-β1 mRNA levels were higher in PPAs-T2D. Fetuin-A/palmitate reduced fibronectin, decorin, TIMP-1/-2 and TGF-ß1 mRNA levels. Only fibronectin was strongly downregulated by fetuin-A/palmitate independently of the glycemic status. Co-culturing of PPAs with islets increased TIMP-1 mRNA expression in islets. Fetuin-A/palmitate increased MMP-1, usherin and dermatopontin mRNA-levels in co-cultured islets. A transmigration assay showed increased monocyte migration towards PPAs, which was enhanced by fetuin-A/palmitate. This was more pronounced in PPAs-T2D. The expression of distinct ECM components differs in PPAs-PD and PPAs-T2D compared to PPAs-NGR, suggesting that ECM alterations can occur even in mild hyperglycemia. Fetuin-A/palmitate impacts on ECM formation/degradation in PPAs and co-cultured islets. Fetuin-A/palmitate also enhances monocyte migration, a process which might impact on matrix turnover.

Roles of Matrix Metalloproteinases and Their Natural Inhibitors in Metabolism: Insights into Health and Disease

Matrix metalloproteinases (MMPs) are a family of zinc-activated peptidases that can be classified into six major classes, including gelatinases, collagenases, stromelysins, matrilysins, membrane type metalloproteinases, and other unclassified MMPs. The activity of MMPs is regulated by natural inhibitors called tissue inhibitors of metalloproteinases (TIMPs). MMPs are involved in a wide range of biological processes, both in normal physiological conditions and pathological states. While some of these functions occur during development, others occur in postnatal life. Although the roles of several MMPs have been extensively studied in cancer and inflammation, their function in metabolism and metabolic diseases have only recently begun to be uncovered, particularly over the last two decades. This review aims to summarize the current knowledge regarding the metabolic roles of metalloproteinases in physiology, with a strong emphasis on adipose tissue homeostasis, and to highlight the consequences of impaired or exacerbated MMP actions in the development of metabolic disorders such as obesity, fatty liver disease, and type 2 diabetes.

Addition of Resolvins D1 or E1 to Collagen Membranes Mitigates Their Resorption in Diabetic Rats

Uncontrolled diabetes is characterized by aberrant inflammatory reactions and increased collagenolysis. We have reported that it accelerates the degradation of implanted collagen membranes (CM), thus compromising their function in regenerative procedures. In recent years, a group of physiological anti-inflammatory agents called specialized pro-resolving lipid mediators (SPMs) have been tested as a treatment for various inflammatory conditions, either systemically or locally, via medical devices. Yet, no study has tested their effect on the fate of the biodegradable material itself. Here, we measured the in vitro release over time of 100 or 800 ng resolvin D1 (RvD1) incorporated into CM discs. In vivo, diabetes was induced in rats with streptozotocin, while buffer-injected (normoglycemic) rats served as controls. Resolvins (100 or 800 ng of RvD1 or RvE1) were added to biotin-labeled CM discs, which were implanted sub-periosteally over the calvaria of rats. Membrane thickness, density, and uniformity were determined by quantitative histology after 3 weeks. In vitro, significant amounts of RvD1 were released over 1-8 days, depending on the amount loaded. In vivo, CMs from diabetic animals were thinner, more porous, and more variable in thickness and density. The addition of RvD1 or RvE1 improved their regularity, increased their density, and reduced their invasion by the host tissue significantly. We conclude that addition of resolvins to biodegradable medical devices can protect them from excessive degradation in systemic conditions characterized by high degree of collagenolysis.

Pioglitazone inhibits oxidative stress, MMP-mediated inflammation and vascular dysfunction in high glucose-induced human saphenous vein grafts

AIMS

The aim of this study was to investigate the effects of pioglitazone on reactive oxygen species (ROS), expressions/activities of MMPs and TIMP-2, and VSMC proliferation and vascular reactivity in high glucose (HG)-induced human saphenous vein (HSV) grafts.

METHODS

HSV grafts (n = 10) obtained from patients undergoing CABG were incubated with 30 mM glucose and/or 10 μM pioglitazone or 0.1 % DMSO for 24 h after endothelium removal. ROS levels were examined by chemiluminescence assay, MMP-2,-9,-14, TIMP-2, and α-SMA expression/activity was determined by gelatine zymography/immunohistochemistry. Vascular reactivity to potassium chloride, noradrenaline, serotonin, prostaglandin F_2α and papaverine was assessed in HSVs.

RESULTS

HG induced superoxide anion (SA) (123 %) and other ROS levels (159 %), up-regulated MMP-2 expression (180 %)/activity (79 %), MMP-14 expression (24 %) and MMP-9 activity while down-regulating TIMP-2 expression (27 %). HG elevated total MMP-2/TIMP-2 ratio (483 %) and MMP-14/TIMP-2 ratio (78 %). However, HG plus pioglitazone inhibited SA (30 %) and other ROS levels (29 %), down-regulated MMP-2 expression (76 %)/activity (83 %), MMP-14 expression (38 %) and MMP-9 activity, while reversing TIMP-2 expression (44 %). HG plus pioglitazone decreased total MMP-2/TIMP-2 ratio (91 %) and MMP-14/TIMP-2 ratio (59 %). HG impaired contractions to all agents but pioglitazone improved them.

CONCLUSIONS

Pioglitazone may contribute to the prevention of restenosis and maintaining vascular function in HSV grafts of DM patients undergoing CABG.

Antioxidant, Wound Healing Potential and In Silico Assessment of Naringin, Eicosane and Octacosane

1. Diabetic chronic wounds, mainly foot ulcers, constitute one of the most common complications of poorly managed diabetes mellitus. The most typical reasons are insufficient glycemic management, latent neuropathy, peripheral vascular disease, and neglected foot care. In addition, it is a common cause of foot osteomyelitis and amputation of the lower extremities. Patients are admitted in larger numbers attributable to chronic wounds compared to any other diabetic disease. In the United States, diabetes is currently the most common cause of non-traumatic amputations. Approximately five percent of diabetics develop foot ulcers, and one percent require amputation. Therefore, it is necessary to identify sources of lead with wound-healing properties. Redox imbalance due to excessive oxidative stress is one of the causes for the development of diabetic wounds. Antioxidants have been shown to decrease the progression of diabetic neuropathy by scavenging ROS, regenerating endogenous and exogenous antioxidants, and reversing redox imbalance. Matrix metalloproteinases (MMPs) play vital roles in numerous phases of the wound healing process. Antioxidant and fibroblast cell migration activity of Marantodes pumilum (MP) crude extract has previously been reported. Through their antioxidant, epithelialization, collagen synthesis, and fibroblast migration activities, the authors hypothesise that naringin, eicosane and octacosane identified in the MP extract may have wound-healing properties. 2. The present study aims to identify the bioactive components present in the dichloromethane (DCM) extract of M. pumilum and evaluate their antioxidant and wound healing activity. Bioactive components were identified using LCMS, HPTLC and GCMS. Excision wound on STZ-induced diabetic rat model, human dermal fibroblast (HDF) cell line and colorimetric antioxidant assays were used to evaluate wound healing and antioxidant activities, respectively. Molecular docking and pkCMS software would be utilised to predict binding energy and affinity, as well as ADME parameters. 3. Naringin (NAR), eicosane (EIC), and octacosane (OCT) present in MP displayed antioxidant action and wound excision closure. Histological examination HDF cell line demonstrates epithelialization, collagen production, fibroblast migration, polymorphonuclear leukocyte migration (PNML), and fibroblast movement. The results of molecular docking indicate a substantial attraction and contact between MMPs. pkCMS prediction indicates inadequate blood-brain barrier permeability, low toxicity, and absence of hepatotoxicity. 4. Wound healing properties of (NEO) naringin, eicosane and octacosane may be the result of their antioxidant properties and possible interactions with MMP.

A Review on the Delivery of Plant-Based Antidiabetic Agents Using Nanocarriers: Current Status and Their Role in Combatting Hyperglycaemia

Diabetes mellitus is a prevalent metabolic syndrome that is associated with high blood glucose levels. The number of diabetic patients is increasing every year and the total number of cases is expected to reach more than 600 million worldwide by 2045. Modern antidiabetic drugs alleviate hyperglycaemia and complications that are caused by high blood glucose levels. However, due to the side effects of these drugs, plant extracts and bioactive compounds with antidiabetic properties have been gaining attention as alternative treatments for diabetes. Natural products are biocompatible, cheaper and expected to cause fewer side effects than the current antidiabetic drugs. In this review, various nanocarrier systems are discussed, such as liposomes, niosomes, polymeric nanoparticles, nanoemulsions, solid lipid nanoparticles and metallic nanoparticles. These systems have been applied to overcome the limitations of the current drugs and simultaneously improve the efficacy of plant-based antidiabetic drugs. The main challenges in the formulation of plant-based nanocarriers are the loading capacity of the plant extracts and the stability of the carriers. A brief review of lipid nanocarriers and the amphipathic properties of phospholipids and liposomes that encapsulate hydrophilic, hydrophobic and amphiphilic drugs is also described. A special emphasis is placed on metallic nanoparticles, with their advantages and associated complications being reported to highlight their effectiveness for treating hyperglycaemia. The present review could be an interesting paper for researchers who are working in the field of using plant extract-loaded nanoparticles as antidiabetic therapies.

Matrix Metalloproteinase-2 (MMP-2) and-9 (MMP-9) Gene Variants and Microvascular Complications in Type 2 Diabetes Patients

Vascular complications are the leading cause of increased morbidity and mortality of diabetic patients. It has been postulated that matrix metalloproteinases MMP-2 and MMP-9, zinc-dependent endopeptidases through remodeling of the extracellular matrix, can contribute to the onset and progression of diabetic vascular complications. The aim of our study was to assess whether there is a major difference in single nucleotide polymorphisms in the MMP-2 (at position -1306C˃T) and MMP-9 (at position -1562C˃T) gene in type 2 diabetic patients and healthy controls and to determine whether there is an association of these gene variants with the presence of microvascular complications in diabetic patients. Our study included 102 type 2 diabetes patients and a control group which was comprised of 56 healthy controls. All diabetic patients were screened for microvascular diabetes complications. Genotypes were detected by polymerase chain reactions followed by restriction analyses with specific endonucleases and their frequencies were determined. The MMP-2 variant -1306C>T showed a negative correlation with type 2 diabetes (p=0.028). It was also shown that the presence of the -1306C allele increases the probability of developing type 2 diabetes. This was a 2.2 fold increase and that the -1306 T allele has a protective role in regards to type 2 diabetes. The MMP-2 variant -1306T showed a negative correlation with diabetic polyneuropathy (p=0.017), meaning that allele-1306T has a protective role in regards to diabetic polyneuropathy while the presence of allele -1306C increases the probability of developing diabetic polyneuropathy by 3.4 fold. Our study showed that the MMP-2 gene variant (-1306C) doubles the risk of developing type 2 diabetes, and for the first time an association of this gene variant and the presence of diabetic polyneuropathy was shown.

Association of MMP-2 genes variants with diabetic retinopathy in Tunisian population with type 2 diabetes

AIMS

Few studies investigated the association of genetic difference in metalloproteinase-2 (MMP-2) gene with diabetic retinopathy but with mixed outcome. To investigate the association between a set of MMP-2 genetic variants and the risk of diabetic retinopathy in an Arab Tunisian population with type 2 diabetes.

SUBJECTS AND METHODS

A retrospective case-control study comprising a total of 779 type 2 diabetes patients with or without diabetic retinopathy was conducted. Genotyping was prepared by TaqMan® SNP genotyping qRT-PCR. The variants used were rs243865 (C/T), rs243864 (T/G), rs243866 (G/T) and rs2285053 (C/T).

RESULTS

The minor allele frequency (MAF) of the rs243864 MMP-2 variant was significantly higher among diabetic retinopathy patients. Setting homozygous wild type genotype carrier as reference, the rs243864T/G allele was associated with increased risk of diabetic retinopathy under the dominant, recessive, and additive models which persisted when key covariates were controlled for, while a reduced risk of diabetic retinopathy progression was seen after adjustment between non-proliferative and proliferative diabetic patients. Furthermore, the heterozygous genotype GT of the rs243866 variant is positively associated with the risk of proliferative diabetic retinopathy in the additive model. A limited linkage disequilibrium (LD) was revealed between the four-matrix metalloproteinase-2 variants. Four-loci haplotype analysis identified, GCTC, TTTC, and GCTT haplotypes to be positively associated with the risk of diabetic retinopathy.

CONCLUSION

Our findings demonstrate that the MMP-2 variant rs243864 and 243866 are related to the susceptibility to diabetic retinopathy and the progression of the disease in an Arab Tunisian population with type 2 diabetes.

Association of Matrix Metalloproteinases with Coronary Artery Calcification in Patients with CHD

This work is aimed at studying the relationship of matrix metalloproteinases with calcification of the coronary arteries. The study included 78 people with coronary heart disease (CHD) and 36 without CHD. Blood and samples of coronary arteries obtained as a result of endarterectomy were examined. Serum levels of metalloproteinases (MMP) MMP-1, MMP-2, MMP-3, MMP-7, MMP-9, MMP-10, MMP-12, and MMP-13 were determined by multiplex analysis. In blood vessel samples, MMP-1, MMP-3, MMP-7, and MMP-9 were determined by enzyme immunoassay; MMP-9 expression was evaluated by immunohistochemistry. Patients with CHD had higher serum levels of MMP-1, MMP-7, and MMP-12. Blood levels of MMP-1 and MMP-3 were associated with calcium levels, MMP-9 with osteoprotegerin and osteonectin, MMP-7 and MMP-10 with osteoprotegerin, MMP-12 with osteocalcin, and MMP-13 with osteopontin. Calcified plaques had higher levels of MMP-1 and MMP-9 compared to plaques without calcification. The relative risk of coronary arteries calcification was associated with MMP-9, which is confirmed by the results of immunohistochemistry. The results obtained indicate the participation of some MMPs, and especially MMP-9, in the calcification processes. The study can serve as a basis for the further study of the possibility of using MMP-1, MMP-7 and MMP-12 as potential biomarkers of CHD.

Fibroproliferative disorders and diabetes: Understanding the pathophysiologic relationship between Peyronie's disease, Dupuytren disease and diabetes

Introduction

Fibrosis is characterized by dysregulation and accumulation of extracellular matrix. Peyronie's disease and Dupuytren disease are fibroproliferative disorders of the tunica albuginea of the penis and fascia of the hand, respectively. Chronic hyperglycaemia due to diabetes mellitus can also lead to tissue injury and fibrosis. A meta-analysis has shown a relationship between Dupuytren disease and diabetes (overall odds ratio, 3.1; 95% confidence interval, 2.7-3.5). This review explores commonalities in the pathogenesis of Peyronie's disease, Dupuytren disease and diabetes.

Methods

A search of the PubMed database was conducted using the search terms "diabetes" AND "Peyronie's disease"; and "diabetes" AND "Dupuytren."

Results

Genome-wide association and gene expression studies conducted with tissue from people with Peyronie's disease or Dupuytren disease identified signalling pathways associated with wingless-type mammary-tumour virus integration site signalling, extracellular matrix modulation and inflammation. Biochemical studies confirmed the importance of these pathways in the pathogenesis of fibrosis with Peyronie's disease and Dupuytren disease. Dysregulation of matrix metalloproteinase activity associated with extracellular matrix breakdown was implicated in fibroproliferative complications of diabetes and in the aetiology of Peyronie's disease and Dupuytren disease. A notable percentage of people with diabetes have comorbid Peyronie's disease and/or Dupuytren disease.

Conclusions

Studies have not been performed to identify fibroproliferative pathways that all 3 conditions might have in common, but data suggest that common pathways are involved in the fibroproliferative processes of Peyronie's disease, Dupuytren disease, and diabetes.

Hyperglycemic levels in early stage of diabetic nephropathy affect differentially renal expression of claudins-2 and -5 by oxidative stress

AIMS

This study attempts to elicit whether the level of hyperglycemia in an early stage of diabetic nephropathy changes the renal expression of claudins-2 and -5 and to determine the involvement of glucose-induced oxidative stress.

MAIN METHODS

Streptozotocin-induced type-1 and type-2 diabetic (DM1, DM2)-rat models were used. At 14-week old, the rats were placed in metabolic cages to evaluate proteinuria, creatinine clearance, and electrolyte excretion. Proximal tubules and glomeruli were isolated and analyzed by Western blot and immunofluorescence. Renal oxidative stress and metalloproteinase activities were evaluated.

KEY FINDINGS

We found that claudin-5 expression in glomeruli and claudin-2 expression in proximal tubules were significantly reduced in DM1 versus DM2 model, paralleling with higher proteinuria and loss of sodium and potassium reabsorption, increased malondialdehyde levels, but lower antioxidant capacity in both models. Enzymatic activity of MMP-2 and-9 was increased in both diabetic groups versus control being higher in DM1 than DM2, suggesting higher claudin's degradation.

SIGNIFICANCE

The level of hyperglycemia determines the time-dependent progression to diabetic nephropathy; hyperglycemia-induced oxidative stress parallels an increase in metalloproteinases (MMPs) activities consequently affecting the integrity of claudin-2 and -5 in glomerulus and proximal tubule. Our results suggest that chronic high-glycemia levels in early stages of diabetic nephropathy decrease expression of claudins-2 and -5, increase oxidative stress, and induce MMP-activity faster than chronic middle-glycemia levels.

Plasma levels of tissue inhibitor of metalloproteinase-1 in patients with type 1 diabetes mellitus associate with early diabetic neuropathy and nephropathy

BACKGROUND

Tissue inhibitor of metalloproteinase-1 (TIMP-1) has been suggested as a marker for abnormal regulation of tissue remodelling in type 1 diabetes. Metalloproteinase-9 (MMP-9) has been associated with matrix turnover, and Neutrophil gelatinase associated lipocalin (NGAL) is a marker of tubular injury in diabetic nephropathy. The aim was to analyse these biomarkers to unmask early diabetic complications.

METHODS

Thirty-three type 1 diabetes patients, aged 20-35 years, and disease duration 20 ± 5.3 years were included. Along with clinical examination, neurophysiological measurements, routine biochemistry, plasma concentrations of TIMP-1, MMP-9 and NGAL were determined with immunoenzymatic techniques.

RESULTS

TIMP-1 correlated with abnormal unilateral and bilateral vibratory sense foot perception (r = -0.49 and r = -0.51, respectively), foot neuropathy impairment assessment score (NIA; r = -0.55), neuropathy symptom assessment score (r = 0.42), microalbuminuria (r = 0.50) and eGFR (r = -0.45). MMP-9 correlated with impaired foot NIA (r = 0.51). Multiple regression analysis showed an association for TIMP-1 (p = 0.004) with impaired neurophysiological examinations and renal dysfunction along with NGAL (p = 0.016 and p = 0.015 respectively).

CONCLUSIONS

This study suggests that plasma levels of TIMP-1, MMP-9 and NGAL may serve as useful biomarkers in unravelling subclinical neuropathy and nephropathy in type 1 diabetes.

Matrix Metalloproteinases and Hypertension-Mediated Organ Damage: Current Insights

Matrix metalloproteinases (MMPs) are important extracellular enzymes involved in many physiological and pathological processes. Changes in the activity and concentration of specific MMPs, as well as the unbalance with their inhibitors (tissue inhibitors of metalloproteinases – TIMPs), have been described as a part of the pathogenic cascade promoted by arterial hypertension. MMPs are able to degrade various protein substrates in the extracellular matrix, to influence endothelial cells function, vascular smooth muscle cells migration, proliferation and contraction, and to stimulate cardiomyocytes changes. All these processes can be activated by chronically elevated blood pressure values. Animal and human studies demonstrated the key function of MMPs in the pathogenesis of hypertension-mediated vascular, cardiac, and renal damage, besides age and blood pressure values. Thus, the role of MMPs as biomarkers of hypertension-mediated organ damage and potential pharmacological treatment targets to prevent further cardiovascular and renal complications in hypertensive population is increasingly supported. In this review, we aimed to describe the main scientific evidence about the behavior of MMPs in the development of vascular, cardiac, and renal damage in hypertensive patients.

Ascorbic acid inhibits vascular remodeling induced by mental stress in overweight/obese men

BACKGROUND

Mental stress (MS) is related to endothelial dysfunction in overweight/obese men. It is believed that the pro-oxidant profile, associated with an imbalance in the vascular remodeling process, may contribute to deleterious effects of MS on endothelial function. However, it is unknown whether administration of ascorbic acid (AA), a potent antioxidant, can prevent oxidative and remodeling dysfunction during MS in these subjects.

METHODS

Fourteen overweight/obese grade I men (27 ± 7 years; 29.7 ± 2.6 kg·m^-2) underwent the Stroop Color Word Test for 5 min to induce MS after AA (3 g) or placebo (PL, 0.9% NaCl) intravenous infusions. Venous blood samples were collected at baseline and the last minute of MS to measure nitrite concentration (chemiluminescence), protein carbonylation, thiobarbituric acid reactive substances (TBARS) and catalase activity (colorimetric assays), superoxide dismutase (SOD; immunoenzymatic assay), activities of active/inactive (pro) forms of metalloproteinases-9 and -2 (MMP; zymography) and its respective tissue inhibitors concentration (TIMP-1 and TIMP-2; immunoenzymatic assays).

RESULTS

At baseline, MMP-9 activity (p < 0.01), the MMP-9/proMMP-9 ratio (p = 0.02) and TIMP-1 concentration (p = 0.05) were reduced, whereas proMPP-9 activity was increased (p = 0.02) after AA compared to PL infusion. After PL infusion, MS increased protein carbonylation (p < 0.01), catalase (p < 0.01), and the MMP-9/proMMP-9 ratio (p = 0.04) when compared to baseline. AA infusion reduced protein carbonylation (p = 0.02), MMP-9 activity (p < 0.01), and MMP-9/pro-MMP-9 ratio (p < 0.01), while SOD (p = 0.04 vs baseline), proMPP-9 (p < 0.01 vs PL), MMP-2 (p < 0.01 vs PL) and TIMP-2 (p = 0.02 vs baseline) remained elevated during MS.

CONCLUSIONS

AA appears to minimize the oxidative imbalance and vascular remodeling induced by MS.

Naringenin ameliorates diabetic neuropathic pain by modulation of oxidative-nitrosative stress, cytokines and MMP-9 levels

Diabetes mellitus is a serious debilitating epidemic affecting all social strata, imposing huge health, social and economic burdens.

Coagulatory Defects in Type-1 and Type-2 Diabetes

Diabetes (both type-1 and type-2) affects millions of individuals worldwide. A major cause of death for individuals with diabetes is cardiovascular diseases, in part since both types of diabetes lead to physiological changes that affect haemostasis. Those changes include altered concentrations of coagulatory proteins, hyper-activation of platelets, changes in metal ion homeostasis, alterations in lipid metabolism (leading to lipotoxicity in the heart and atherosclerosis), the presence of pro-coagulatory microparticles and endothelial dysfunction. In this review, we explore the different mechanisms by which diabetes leads to an increased risk of developing coagulatory disorders and how this differs between type-1 and type-2 diabetes.

The Connection of Periodontal Disease and Diabetes Mellitus: The Role of Matrix Metalloproteinases and Oxidative Stress

Diabetes mellitus, a chronic disease considered by the World Health Organization to be an epidemic, is now recognized as one of the factors behind the onset of periodontal disease. The connection between periodontal disease, which is an irreversible inflammatory disease of the supporting tissue of the teeth, and systemic diseases is reflected in the existence of common risk factors, subgingival dental biofilm, as a constant source of proinflamma-tory cytokines synthesized intensely in inflammatory periodontium. Diabetes mellitus leads to increased oxidative stress in periodontal tissues causing worsening of the disease and periodontopathy exacerbates deficiency of pancreatic β-cells. The most important role in primary inflammatory response in the pathogenesis of periodontopathy is played by neutrophils. Neutrophils cause periodontium destruction by the release of enzymes (matrix metalloproteinases), cytotoxic substances (free radicals, reactive oxygen and nitrogen species) and the expression of membrane receptors. Matrix metalloproteinases within the “protease network” are critical to many physiological and pathological processes, including immunity, inflammation, bone resorption and wound healing. Matrix metalloproteinases levels are elevated in patients with metabolic syndrome and diabetes mellitus, which may contribute to more frequent complications. In this paper, the review of available literature data shows the correlation between periodontal disease and diabetes mellitus, as well as the role of matrix metalloproteinases and oxidative stress in these. In this regard, determining the value of matrix metalloproteinases may be helpful in the diagnosis of periodontal disease complicated by diabetes mellitus. Also, the parameters of oxidative stress could help to clarify the mechanisms of pathogenesis and etiology of periodontal disease, or indicate the potential benefit of antioxidant supplementation in these individuals. As the role of matrix metalloproteinases has not been fully clarified in the pathogenesis of periodontopathy, additional studies will be needed to indicate their importance.

Does Arterial Hypertension Affect Plasma Levels of Matrix Metalloproteinases and Their Tissue Inhibitors in Patients with Stable Coronary Artery Disease? A Preliminary Study

Background

Arterial hypertension (HT) is a serious and prevalent epidemiological factor in the development of coronary artery disease (CAD). Metalloproteinases (MMPs), especially MMP-2 and MMP-9, and their natural endogenous tissue inhibitors (TIMPs) are involved in the pathogenesis of HT and its complications. MMPs are also involved in the development of diabetes (DM), a risk factor for CAD. The aim of the study was to explore the influence of CAD, HT, and DM on changes in plasma levels of MMP-2 and MMP-9 and their inhibitor TIMP-4.

Methods and Results

The study involved 70 patients with stable CAD admitted for coronary angiography and 15 healthy subjects. Whole blood samples were collected prior to angiography. MMP-2, MMP-9, and TIMP-4 levels in plasma were estimated using ELISA tests. CAD patients showed a significantly increased level of TIMP-4 and decreased level of MMP-2 in comparison to healthy controls (p=0.011 and p=0.037, respectively). Concentration of MMP-2, MMP-9, and TIMP-4 did not differ in the group with and without hypertension. Patients with DM presented higher MMP-2 level than patients without DM (p < 0.001). Multiple regression analysis of the influence of independent variables such as CAD stage, DM, and HT on MMP-2, MMP-9, and TIMP-4 showed that only DM was independently associated with a higher level of MMP-2 (β = 0.42, R² = 0.17, p < 0.001).

Conclusion

Data showed that patients with CAD presented higher TIMP-4 and lower MMP-2 concentration regardless of HT and DM. HT had no effect on MMP-2, MMP-9, and TIMP-4 levels in serum. DM was independently associated with higher MMP-2 concentration; however, co-occurrence of CAD and DM was associated with the balance in the MMP-2 level. Concentration of MMP-9 did not change significantly in any of the analysed groups.

Adipose-derived Stem Cells Attenuates Diabetic Osteoarthritis via Inhibition of Glycation-mediated Inflammatory Cascade

Diabetes mellitus (DM) is well-known to exert complications such as retinopathy, cardiomyopathy and neuropathy. However, in recent years, an elevated osteoarthritis (OA) complaints among diabetics have been observed, portending the risk of diabetic OA. Since formation of advanced glycation end products (AGE) is believed to be the etiology of various diseases under hyperglycemic conditions, we firstly established that streptozotocin-induced DM could potentiate the development of OA in C57BL/6J mouse model, and further explored the intra-articularly administered adipose-derived stem cell (ADSC) therapy focusing on underlying AGE-associated mechanism. Our results demonstrated that hyperglycemic mice exhibited OA-like structural impairments including a proteoglycan loss and articular cartilage fibrillations in knee joint. Highly expressed levels of carboxymethyl lysine (CML), an AGE and their receptors (RAGE), which are hallmarks of hyperglycemic microenvironment were manifested. The elevated oxidative stress in diabetic OA knee-joint was revealed through increased levels of malondialdehyde (MDA). Further, oxidative stress-activated nuclear factor kappa B (NF-κB), the marker of proinflammatory signalling pathway was also accrued; and levels of matrix metalloproteinase-1 and 13 were upregulated. However, ADSC treatment attenuated all OA-like changes by 4 weeks, and dampened levels of CML, RAGE, MDA, NF-κB, MMP-1 and 13. These results suggest that during repair and regeneration, ADSCs inhibited glycation-mediated inflammatory cascade and rejuvenated cartilaginous tissue, thereby promoting knee-joint integrity in diabetic milieu.

Cardiovascular organ damage in type 2 diabetes mellitus: the role of lipids and inflammation

Background

The relationship between dyslipidemia, inflammation and CV organ damage in type 2 diabetes mellitus (T2DM) is complex. Insulin resistance and inflammatory cytokines interleukins (ILs) increase plasma triglycerides (TG). ILs also up-regulate expression of matrix-metalloproteinases (MMPs) that, together with TG, decrease high density lipoprotein cholesterol (HDL) levels. High TG, low HDL, increased ILs and MMPs trigger structural and functional changes in different parts of cardiovascular (CV) system. To understand better the role of lipids and inflammation in CV organ damage, the present study investigated the inter-relationships between lipids, ILs and MMPs, as well as the associations of lipids, ILs and MMPs with various CV measures, both in diabetic and non-diabetic population (nonT2DM).

Methods

In T2DM patients (N = 191) and nonT2DM subjects (N = 94) were assessed carotid intima-media thickness (cIMT) and inter-adventitial diameter (IADiam), carotid wave speed (ccaWS), carotid-femoral pulse wave velocity (cfPWV), left ventricular (LV) mass, LV systolic (s′) and early diastolic (e′) longitudinal velocities of mitral annulus, together with glycemic control, lipid profile, IL-6, IL-18 and MMP-12.

Results

T2DM patients, as compared to nonT2DM subjects, had significantly higher plasma levels of IL-6, IL-18, MMP-12 and lower HDL (P < 0.05–0.0001). They had also higher cIMT, IADiam, ccaWS, cfPWV and LV mass, and lower e′ velocity (P < 0.005–0.0001). Both in T2DM patients and nonT2DM subjects, MMP-12 increased with IL-6 (r = 0.43 and 0.39; P < 0.0001) and IL-18 (r = 0.32 and 0.42; P < 0.0001), and HDL decreased with MMP-12 (r = − 0.29 and − 0.42; P < 0.0001). In both populations, MMP-12 was directly associated with IADiam, ccaWS, cfPWV and LV mass (r = 0.42, 0.32, 0.26 and 0.29; P < 0.0001 in T2DM patients, and r = 0.39, 0.28, 0.32 and 0.27; P < 0.01–0.0001 in nonT2DM subjects). In multivariate analysis, MMP-12 remained independently related to IADiam, ccaWS, cfPWV and LV mass in T2DM patients, and to IADiam only in nonT2DM subjects.

Conclusions

This cross-sectional study demonstrated a direct association between ILs and MMP-12, as well as an inverse association between MMP-12 and HDL, both in T2DM patients and in nonT2DM subjects. In T2DM patients, who had higher levels of ILs and MMP-12, the latter was independently related to several structural and functional markers of preclinical CV organ damage.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0865-6) contains supplementary material, which is available to authorized users.

Liposomal Curcumin is Better than Curcumin to Alleviate Complications in Experimental Diabetic Mellitus

Curcumin (CC) is known to have anti-inflammatory and anti-oxidative properties and has already been tested for its efficiency in different diseases including diabetes mellitus (DM). New formulations and route administration were designed to obtain products with higher bioavailability. Our study aimed to test the effect of intraperitoneal (i.p.) administration of liposomal curcumin (lCC) as pre-treatment in streptozotocin(STZ)-induced DM in rats on oxidative stress, liver, and pancreatic functional parameters. Forty-two Wistar-Bratislava rats were randomly divided into six groups (seven animals/group): control (no diabetes), control-STZ (STZ-induced DM —60 mg/100g body weight a single dose intraperitoneal administration, and no CC pre-treatment), two groups with DM and CC pre-treatment (1mg/100g bw—STZ + CC1, 2 mg/100g bw—STZ + CC2), and two groups with DM and lCC pre-treatment (1 mg/100g bw—STZ + lCC1, 2 mg/100g bw—STZ + lCC1). Intraperitoneal administration of Curcumin in diabetic rats showed a significant reduction of nitric oxide, malondialdehyde, total oxidative stress, and catalase for both evaluated formulations (CC and lCC) compared to control group (p < 0.005), with higher efficacy of lCC formulation compared to CC solution (p < 0.002, excepting catalase for STZ + CC2vs. STZ + lCC1when p = 0.0845). The CC and lCC showed hepatoprotective and hypoglycemic effects, a decrease in oxidative stress and improvement in anti-oxidative capacity status against STZ-induced DM in rats (p < 0.002). The lCC also proved better efficacy on MMP-2, and -9 plasma levels as compared to CC (p < 0.003, excepting STZ + CC2 vs. STZ + lCC1 comparison with p = 0.0553). The lCC demonstrated significantly better efficacy as compared to curcumin solution on all serum levels of the investigated markers, sustaining its possible use as adjuvant therapy in DM.

Role of matrix metalloproteinases and histone deacetylase in oxidative stress-induced degradation of the endothelial glycocalyx

The glycocalyx is crucial for normal endothelial function. It also tethers extracellular superoxide dismutase (SOD3), which protects the endothelium against oxidative damage. Proteolytic enzymes [matrix metalloproteinases (MMPs)] are capable of disrupting endothelial cell surface proteins, such as syndecans, resulting in derangements of the endothelial glycocalyx. We sought to test the role of MMPs in oxidative stress-mediated disruption of the endothelial glycocalyx and examine the effect of pharmacological inhibition of MMPs on mitigating this detrimental effect. We also examined the role of histone deacetylase (HDAC) in the oxidative stress-mediated MMP induction and glycocalyx remodeling. Oxidative stress was experimentally induced in human adipose microvascular endothelial cells using H₂O₂ and buthionine sulfoximine in the presence and absence of potent MMP and HDAC inhibitors. H₂O₂ and buthionine sulfoximine resulted in a notable loss of the endothelial glycocalyx; they also increased the expression and proteolytic activity of MMP-2 and MMP-9 and subsequently increased the shedding of syndecan-1 and SOD3 from the endothelial cell surface. MMP upregulation was accompanied by a decline in mRNA and protein levels of their inhibitors, tissue inhibitors of metalloproteinase (TIMPs; TIMP-1 and TIMP-3). Furthermore, oxidative stress induced HDAC activity. Inhibition of MMPs and HDAC reversed syndecan-1 and SOD3 shedding and maintained endothelial glycocalyx integrity. HDAC inhibition increased TIMP expression and reduced MMP expression and activity in endothelial cells. Our findings shed light on MMPs and HDAC as therapeutically targetable mechanisms in oxidative stress-induced glycocalyx remodeling. NEW & NOTEWORTHY Oxidative stress, a hallmark of many diseases, damages the endothelial glycocalyx, resulting in vascular dysfunction. Studying the mechanistic link between oxidative stress and endothelial glycocalyx derangements might help discover new therapeutic targets to preserve vascular function. In this study, we investigated the involvement of matrix metalloproteinases and histone deacetylase in oxidative stress-induced endothelial glycocalyx degradation.

Metalloproteinase Changes in Diabetes

Matrix metalloproteinases (MMPs) constitute a group of over 20 structurally-related proteins which include a Zn(++) ion binding site that is essential for their proteolytic activities. These enzymes play important role in extracellular matrix turnover in order to maintain a proper balance in its synthesis and degradation. MMPs are associated to several physiological and pathophysiological processes, including diabetes mellitus (DM). The mechanisms of DM and its complications is subject of intense research and evidence suggests that MMPs are implicated with the development and progression of diabetic microvascular complications such as nephropathy, cardiomyopathy, retinopathy and peripheral neuropathy. Recent data has associated DM to changes in the tendon structure, including abnormalities in fiber structure and organization, increased tendon thickness, volume and disorganization obtained by image and a tendency of impairing biomechanical properties. Although not fully elucidated, it is believed that DM-induced MMP dysregulation may contribute to structural and biomechanical alterations and impaired process of tendon healing.

Crocus sativus L. aqueous extract reduces atherogenesis, increases atherosclerotic plaque stability and improves glucose control in diabetic atherosclerotic animals

BACKGROUND AND AIMS

We aimed to evaluate a possible atheroprotective effect of saffron aqueous extract (SFE), and its potential anti-inflammatory mechanisms, in apoE knockout (ApoE^-/-) mice.

METHODS

Fifty male, ApoE^-/- mice, fed a high-fat diet (HFD) for 12 weeks, were randomized into 5 groups: (1) baseline group, euthanatized, without intervention, (2) three saffron groups, receiving HFD and 30,60,90 mg/kg/day of SFE, respectively, for four weeks, per os through gavage, after reconstitution in water for injection (WFI), (3) control group (COG), receiving daily HFD and the same volume of WFI (four weeks). After blood sampling and euthanasia, aortic roots were excised and analyzed for gene expression and/or percentage of aortic stenosis, relative content of macrophages, smooth muscle cells (SMCs), connective tissue, tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinases-2,-3,-9 (MMP-2,-3,-9) and their inhibitor (TIMP-2) and IL-6. SFE doses were determined by a pilot serum pharmacokinetic study in C57BL/6J wild-type mice.

RESULTS

SFE did not affect body weight and total cholesterol levels (p > 0.05), while high SFE dose significantly ameliorated glucose and triglycerides profiles compared to other groups (p < 0.05). SFE considerably decreased aortic stenosis in a dose-dependent manner (p < 0.05). Furthermore, increasing SFE doses proportionally reduced macrophages content and increased within plaques content of collagen, elastin, and SMCs, promoting more stable plaque phenotype compared to COG (p < 0.05). Those effects seemed to be associated with a considerable reduction (>30%) in IL-6, TNF-α, MCP-1, MMP-2,-3,-9 (p < 0.05) and MMP-2/TIMP-2 ratio.

CONCLUSIONS

SFE exerted dose-dependent anti-atherosclerotic and plaque-stabilizing effects in Apo-E^-/- mice, probably mediated by a favorable modification of inflammatory mechanisms, which requires further investigation.

Bone disease in diabetes: another manifestation of microvascular disease?

Type 1 and type 2 diabetes are generally accepted to be associated with increased bone fracture risk. However, the pathophysiological mechanisms of diabetic bone disease are poorly understood, and whether the associated increased skeletal fragility is a comorbidity or a complication of diabetes remains under debate. Although there is some indication of a direct deleterious effect of microangiopathy on bone, the evidence is open to question, and whether diabetic osteopathy can be classified as a chronic, microvascular complication of diabetes remains uncertain. Here, we review the current knowledge of potential contributory factors to diabetic bone disease, particularly the association between diabetic microangiopathy and bone mineral density, bone structure, and bone turnover. Additionally, we discuss and propose a pathophysiological model of the effects of diabetic microvascular disease on bone, and examine the progression of bone disease alongside the evolution of diabetes.

Matrix Metalloproteinases, Vascular Remodeling, and Vascular Disease

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that degrade various proteins in the extracellular matrix (ECM). Typically, MMPs have a propeptide sequence, a catalytic metalloproteinase domain with catalytic zinc, a hinge region or linker peptide, and a hemopexin domain. MMPs are commonly classified on the basis of their substrates and the organization of their structural domains into collagenases, gelatinases, stromelysins, matrilysins, membrane-type (MT)-MMPs, and other MMPs. MMPs are secreted by many cells including fibroblasts, vascular smooth muscle (VSM), and leukocytes. MMPs are regulated at the level of mRNA expression and by activation through removal of the propeptide domain from their latent zymogen form. MMPs are often secreted in an inactive proMMP form, which is cleaved to the active form by various proteinases including other MMPs. MMPs degrade various protein substrates in ECM including collagen and elastin. MMPs could also influence endothelial cell function as well as VSM cell migration, proliferation, Ca²⁺ signaling, and contraction. MMPs play a role in vascular tissue remodeling during various biological processes such as angiogenesis, embryogenesis, morphogenesis, and wound repair. Alterations in specific MMPs could influence arterial remodeling and lead to various pathological disorders such as hypertension, preeclampsia, atherosclerosis, aneurysm formation, as well as excessive venous dilation and lower extremity venous disease. MMPs are often regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and the MMP/TIMP ratio often determines the extent of ECM protein degradation and tissue remodeling. MMPs may serve as biomarkers and potential therapeutic targets for certain vascular disorders.

MMP-2, MMP-9, and TIMP-4 and Response to Aspirin in Diabetic and Nondiabetic Patients with Stable Coronary Artery Disease: A Pilot Study

Background

High on-aspirin treatment platelets reactivity (HPR) is a significant problem in long-term secondary prevention of cardiovascular events. We hypothesize that imbalance between platelets MMPs/TIMPs results in cardiovascular disorders. We also explored whether chronically elevated blood glucose affects MMP-2/TIMP-4 release from platelets.

Materials and Methods

Seventy patients with stable coronary artery disease, supplemented with aspirin, participated in this pilot study. The presence of HPR and/or diabetes mellitus was considered as the differentiating factor. Light aggregometry, impedance aggregometry, and ELISA tests for TXB2, MMP-2, MMP-9, and TIMP-4 were performed in serum, plasma, platelet-rich plasma, and platelets-poor plasma, as appropriate.

Results

Aspirin-HPR did not affect plasma MMP-2, MMP-9, and TIMP-4. Arachidonic acid-induced aggregation of platelets from aspirin-HPR patients did not lead to increased release of MMP-2, MMP-9, and TIMP-4. Studying patients at the lowest TXB2 serum concentration quartile revealed that high concentration of plasma TIMP-4 and TIMP-4 negatively correlated with TXB2 and platelet aggregation. Diabetics showed an increased plasma MMP-2 as well as an increased MMP-2 in supernatants after platelet aggregation. However, diabetes mellitus did not affect MMP-9 and TIMP-4.

Conclusion

Aspirin-HPR did not affect the translocation and release of MMPs and TIMP-4 from platelets. TIMP-4 may serve as a marker of TXA2-mediated platelet aggregation. Chronically elevated plasma glucose increases plasma MMP-2, and HPR potentiates this phenomenon.

Effect of crocetin on vascular smooth muscle cells migration induced by advanced glycosylation end products

Crocetin is a major active constituent of Gardenia jasminoides J. Ellis, and can aid in the prevention of cardiovascular disease. The effect and possible mechanism of crocetin on the migration of vascular smooth muscle cells (VSMCs) induced by advanced glycosylation end products (AGEs) were investigated. VSMCs were pre-incubated with or without crocetin and exposed to AGEs subsequently. The invasion of the cells was investigated using a 24-well Cell Invasion Chamber. The anti-proliferative activity of crocetin was evaluated by MTT assay and VSMCs cell-cycle distribution was examined by flow cytometry. Cytokine TNF-α and IL-6 secreted by VSMCs and the amount of matrix metalloproteinase MMP-2 and MMP-9 in the culture supernatant were detected by ELISA. The expression level of RAGE (AGEs receptor), in cells was analyzed by western blot. The results demonstrated that AGEs increased about two-fold migration of VSMCs compared with control (OD=0.778±0.191 vs OD=0.413±0.214, P<0.01), and the proliferation increased by about 20% (OD=0.335±0.043 vs OD=0.281±0.037, P<0.01). Pre-treatment with crocetin (1.0μM) or RAGE antibody (10μg/ml) could inhibit the AGEs triggered migration of VSMCs obviously. Furthermore, both crocetin and RAGE antibody inhibited the increase of RAGE protein in VSMCs stimulated by AGEs. The levels of TNF-α and IL-6 decreased in the crocetin (1.0μM) pre-treated group compared to the AGEs (without pre-treated) group (37.60±3.08pg/ml vs 46.59±1.92pg/ml, 32.11±4.69pg/ml vs 49.99±8.84pg/ml, respectively). Crocetin (1.0μM) also reduced the value of MMP-2 and MMP-9 compared with the AGEs group (2.81±0.35ng/ml vs 6.40±0.85ng/ml, 2.69±0.25ng/ml vs 4.32±0.57ng/ml, respectively). In summary, crocetin inhibits the migration of VSMCs induced by AGEs through RAGE-dependent signaling pathway. And it is meaningful to diabetic vascular complications.

Matrix Metalloproteinase Inhibitors as Investigational and Therapeutic Tools in Unrestrained Tissue Remodeling and Pathological Disorders

Matrix metalloproteinases (MMPs) are zinc-dependent proteolytic enzymes that degrade various proteins in the extracellular matrix (ECM). MMPs may also regulate the activity of membrane receptors and postreceptor signaling mechanisms and thereby affect cell function. The MMP family includes collagenases, gelatinases, stromelysins, matrilysins, membrane-type MMPs, and other MMPs. Inactive proMMPs are cleaved by other MMPs or proteases into active MMPs, which interact with various protein substrates in ECM and cell surface. MMPs regulate important biological processes such as vascular remodeling and angiogenesis and may be involved in the pathogenesis of cardiovascular disorders such as hypertension, atherosclerosis, and aneurysm. The role of MMPs is often assessed by measuring their mRNA expression, protein levels, and proteolytic activity using gel zymography. MMP inhibitors are also used to assess the role of MMPs in different biological processes and pathological conditions. MMP activity is regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and the MMP/TIMP balance could determine the net MMP activity, ECM turnover, and tissue remodeling. Also, several synthetic MMP inhibitors have been developed. Synthetic MMP inhibitors include a large number of zinc-binding globulins (ZBGs), in addition to non-ZBGs and mechanism-based inhibitors. MMP inhibitors have been proposed as potential tools in the management of osteoarthritis, cancer, and cardiovascular disorders. However, most MMP inhibitors have broad-spectrum actions on multiple MMPs and could cause undesirable musculoskeletal side effects. Currently, doxycycline is the only MMP inhibitor approved by the Food and Drug Administration. New generation biological and synthetic MMP inhibitors may show greater MMP specificity and fewer side effects and could be useful in targeting specific MMPs, reducing unrestrained tissue remodeling, and the management of MMP-related pathological disorders.

The role of exercise training and the endocannabinoid system in atherosclerotic plaque burden and composition in Apo-E-deficient mice

INTRODUCTION

We investigated the effect of combining exercise training and treatment with an endocannabinoid receptor 1 inhibitor (Rimonabant) on atherosclerosis burden and composition.

METHODS

Forty-eight apolipoprotein E-deficient (ApoE-/-) mice were kept on a 16-week high-fat diet. Mice were then placed on a normal diet and were randomized to the following groups with n=12 mice for 6 more weeks: 1) Control (Co) - no intervention; 2) Exercise (Ex) - exercise training on treadmill; 3) Rimonabant (Ri) - oral administration of rimonabant (10 mg/kg/day); or 4) Rimonabant+Exercise (RiEx) - combination of Ri and Ex groups treatment. At the end, all animals were sacrificed, and blood samples, as well as aortic root specimens, were obtained for histomorphometric analysis and quantification of the serum and plaque content of matrix metalloproteinases (MMPs).

RESULTS

The mean plaque area was significantly smaller (RiEx: 43.18±1.72%, Ri: 44.66±3.1%, Ex: 49±4.10%, Co: 70.43±2.83%) in all active treatment groups relative to the Co group (p<0.01). Conversely, the relative concentrations of collagen and elastin were increased significantly across all treatment groups compared to Co (p<0.05). Immunohistochemical analysis revealed significantly reduced macrophage content within plaques after all interventions, with the most pronounced effect observed after combined treatment (RiEx: 9.4±3.92%, Ri: 15±2.45%, Ex: 19.78±2.79%, Co: 34.25±4.99%; p<0.05). Within plaques, the TIMP-1 concentration was significantly upregulated in exercise-treated groups. MMP-3 and MMP-9 concentrations were equivalently decreased in all three active treatment groups compared to controls (p<0.001).

DISCUSSION

Both exercise and rimonabant treatments induced plaque regression and promoted plaque stability. The combined treatment failed to show additive or synergistic benefits relative to either intervention alone.

Substrate-zymography: a still worthwhile method for gelatinases analysis in biological samples

Matrix metallo-proteinases (MMPs) are a family of zinc-dependent endopeptidases, capable of degrading all the molecular components of extracellular matrix. A class of MMPs is gelatinases which includes gelatinase A or MMP-2 (72 kDa) and gelatinase B or MMP-9 (92 kDa), which have been shown to play critical roles in pathophysiology of many human disease and, in particular, cancer progression. For these reasons they obtained a great interest as potential non-invasive biomarker in providing useful clinical information in cancer diagnosis and therapy. A sensitive and unexpensive method for analysis of gelatinases is the gelatine zymography, which allows to measure the relative amounts of active and inactive enzymes in body fluids and tissue extracts. The procedure involves the electrophoretic separation of proteins under denaturing but non reducing conditions through a polyacrylamide gel containing a synthetic substrate (gelatin). The aim of this mini-review has been to describe the general principles of gelatine zymography technique, underling the main advantages and disadvantages. Even though an improvement of this method is necessary for a better applicability in laboratory medicine, gelatine zymography represents the most convenient method to detect the activity of the different gelatinases from a wide range of biological samples.

Association of potential salivary biomarkers with diabetic retinopathy and its severity in type-2 diabetes mellitus: a proteomic analysis by mass spectrometry

AIM/HYPOTHESIS

The aim of our study was to characterize the human salivary proteome and determine the changes in protein expression in two different stages of diabetic retinopathy with type-2 diabetes mellitus: (1) with non-proliferative diabetic retinopathy (NPDR) and (2) with proliferative diabetic retinopathy (PDR). Type-2 diabetes mellitus without diabetic retinopathy (XDR) was designated as control.

METHOD

In this study, 45 saliva samples were collected (15 samples from XDR control group, 15 samples from NPDR disease group and 15 samples from PDR disease group). Salivary proteins were extracted, reduced, alkylated, trypsin digested and labeled with an isobaric tag for relative and absolute quantitation (iTRAQ) before being analyzed by an Orbitrap fusion tribrid mass spectrometer. Protein annotation, fold change calculation and statistical analysis were interrogated by Proteome Discoverer. Biological pathway analysis was performed by Ingenuity Pathway Analysis. Data are available via ProteomeXchange with identifiers PXD003723-PX003725.

RESULTS

A total of 315 proteins were identified from the salivary proteome and 119 proteins were found to be differentially expressed. The differentially expressed proteins from the NPDR disease group and the PDR disease group were assigned to respective canonical pathways indicating increased Liver X receptor/Retinoid X receptor (LXR/RXR) activation, Farnesoid X receptor/Retinoid X receptor (FXR/RXR) activation, acute phase response signaling, sucrose degradation V and regulation of actin-based motility by Rho in the PDR disease group compared to the NPDR disease group.

CONCLUSIONS/INTERPRETATION

Progression from non-proliferative to proliferative retinopathy in type-2 diabetic patients is a complex multi-mechanism and systemic process. Furthermore, saliva was shown to be a feasible alternative sample source for diabetic retinopathy biomarkers.

Effects of various stages of nephropathy on wound healing in patients with diabetes: an observational cohort study encompassing 731 diabetics

BACKGROUND AND OBJECTIVE

In diabetics genetic predisposition, poor glycemic control and arterial hypertension contribute to nephropathy development in patients affected by diabetes mellitus. We set up the hypothesis that diabetic nephropathy and incisional hernia formation may have in common alterations of collagen composition and tested whether the occurrence of diabetic nephropathy coincides with wound healing disturbance (incisional herniation) or connective tissue diseases (inguinal herniation, umbilical herniation, aortic aneurysm, varicose veins, disc herniation).

DESIGN

A questionnaire on surgical procedures, wound healing and connective tissue disorders was performed with 731 diabetics. Furthermore, test results for kidney function and damage (creatinine clearance, proteinuria) and blood sugar control (HbA1c) were recorded. Correlations between aforementioned connective tissue diseases and "advanced" diabetic nephropathy were calculated. "Advanced" diabetic nephropathy was assumed in patients with macroproteinuria, CKD stage 5 and/or end-stage renal disease. All diabetics with CKD stages 1 and 2 without proteinuria were included in the "control" group. A subgroup analysis on incisional hernia formation coinciding with diabetic nephropathy was performed in patients with previously performed abdominal surgery.

RESULTS

In patients with advanced nephropathy, some diseases with connective tissue alterations, such as inguinal herniation, aortic aneurysms and varicose veins, did not occur more frequently than in patients without nephropathy. In diabetics with nephropathy, umbilical herniation (3 vs. 8.2 %, p = 0.04) and disc herniation rates (5.7 vs. 16.1 %, p = 0.002) were significantly lower. Subgroup analysis of patients with previously performed abdominal surgery (n = 381) revealed significantly higher incisional herniation rates when "advanced" diabetic nephropathy was present (16 % compared to 5.7 % without nephropathy, p = 0.016).

CONCLUSION

Our findings support the hypothesis that incisional hernia formation and diabetic nephropathy are positively correlated. Conversely, umbilical and disc herniation pathomechanisms are distinct, as these negatively correlate with the presence of advanced diabetic nephropathy.

Decreases in plasma MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios in uremic patients during hemodialysis

BACKGROUND

Matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors (TIMPs) play important roles in the pathophysiology of renal diseases. Imbalanced MMPs/TIMPs are implicated in the vascular alterations of uremic patients on hemodialysis (HD). We have investigated the plasma levels of MMP-2, MMP-9, TIMP-1 and TIMP-2 in uremic patients and the effects of a course of HD on the changes in these factors.

METHODS

There were 382 uremic patients on regular HD treatment and 50 healthy controls enrolled in this study. The plasma MMP-2 and MMP-9 levels were detected by gelatin zymography, and TIMP-1 and TIMP-2 concentrations were determined by ELISA assay.

RESULTS

Significantly higher plasma MMP-2 and MMP-9 and decreased TIMP-1 in the uremic patients were detected compared with those in the controls. Therefore, there were markedly higher MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios in the uremic patients. In the course of a single HD session, the plasma MMP-2 level was significantly decreased from pre-HD to post-HD. TIMP-1 concentration was significantly increased from pre-HD to post-HD. Although the HD session did not have a significant effect on the levels of plasma MMP-9 and TIMP-2, both plasma MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios were significantly decreased from pre-HD to post-HD levels.

CONCLUSION

HD session could decrease MMP-2 and increase TIMP-1 level in the circulation of uremic patients. The physiological significance of reduced MMPs/TIMPs ratio due to a single HD session is required to further validate.

Loss of survival factors and activation of inflammatory cascades in brain sympathetic centers in type 1 diabetic mice

Neuroinflammation and neurodegeneration have been observed in the brain in type 1 diabetes (T1D). However, little is known about the mediators of these effects. In T1D mice with 12- and 35-wk duration of diabetes we examined two mechanisms of neurodegeneration, loss of the neuroprotective factors insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) and changes in indoleamine 2,3-dioxygenase (IDO) expression in the brain, and compared the response to age-matched controls. Furthermore, levels of matrix metalloproteinase-2 (MMP-2), nucleoside triphosphate diphosphohydrolase-1 (CD39), and ionized calcium-binding adaptor molecule 1 (Iba-1) were utilized to assess inflammatory changes in astrocytes, microglia, and blood vessels. In the diabetic hypothalamus (HYPO), we observed 20% reduction in neuronal soma diameter (P<0.05) and reduced neuronal expression of IGFBP-3 (-32%, P<0.05) and IGF-I (-15%, P<0.05) compared with controls at 35 wk. In diabetic HYPO, MMP-2 expression was increased in astrocytes (46%, P<0.01), and IDO⁺ cell density rose by (62%, P<0.05). CD39 expression dropped by 30% (P<0.05) in microglia and blood vessels. With 10 wk of systemic treatment using minocycline, an anti-inflammatory agent that crosses the blood-brain barrier, MMP-2, IDO, and CD39 levels normalized (P<0.05). Our results suggest that increased IDO and early loss of CD39⁺ protective cells lead to activation of inflammation in sympathetic centers of the CNS. As a downstream effect, the loss of the neuronal survival factors IGFBP-3 and IGF-I and the neurotoxic products of the kynurenine pathway contribute to the loss of neuronal density observed in the HYPO in T1D.

A glimpse of matrix metalloproteinases in diabetic nephropathy

Matrix metalloproteinases (MMPs) are proteolytic enzymes belonging to the family of zinc-dependent endopeptidases that are capable of degrading almost all the proteinaceous components of the extracellular matrix (ECM). It is known that MMPs play a role in a number of renal diseases, such as, various forms of glomerulonephritis and tubular diseases, including some of the inherited kidney diseases. In this regard, ECM accumulation is considered to be a hallmark morphologic finding of diabetic nephropathy, which not only is related to the excessive synthesis of matrix proteins, but also to their decreased degradation by the MMPs. In recent years, increasing evidence suggest that there is a good correlation between the activity or expression of MMPs and progression of renal disease in patients with diabetic nephropathy and in various experimental animal models. In such a diabetic milieu, the expression of MMPs is modulated by high glucose, advanced glycation end products (AGEs), TGF-β, reactive oxygen species (ROS), transcription factors and some of the microRNAs. In this review, we focused on the structure and functions of MMPs, and their role in the pathogenesis of diabetic nephropathy.

Volumetric femoral BMD, bone geometry, and serum sclerostin levels differ between type 2 diabetic postmenopausal women with and without fragility fractures

While type 2 diabetes (T2D) is associated with higher skeletal fragility, specific risk stratification remains incompletely understood. We found volumetric bone mineral density, geometry, and serum sclerostin differences between low-fracture risk and high-fracture risk T2D women. These features might help identify T2D individuals at high fracture risk in the future.

INTRODUCTION

Diabetic bone disease, an increasingly recognized complication of type 2 diabetes mellitus (T2D), is associated with high skeletal fragility. Exactly which T2D individuals are at higher risk for fracture, however, remains incompletely understood. Here, we analyzed volumetric bone mineral density (vBMD), geometry, and serum sclerostin levels in two specific T2D subsets with different fracture risk profiles. We examined a T2D group with prior history of fragility fractures (DMFx, assigned high-risk group) and a fracture-free T2D group (DM, assigned low-risk group) and compared their results to nondiabetic controls with (Fx) and without fragility fractures (Co).

METHODS

Eighty postmenopausal women (n = 20 per group) underwent quantitative computed tomography (QCT) to compute vBMD and bone geometry of the proximal femur. Additionally, serum sclerostin, vitamin D, parathyroid hormone (PTH), HbA1c, and glomerular filtration rate (GFR) levels were measured. Statistical analyses employed linear regression models.

RESULTS

DMFx subjects exhibited up to 33 % lower femoral neck vBMD than DM subjects across all femoral sites (-19 % ≤ ΔvBMD ≤ -33 %, 0.008 ≤ p ≤0.021). Additionally, DMFx subjects showed significantly thinner cortices (-6 %, p = 0.046) and a trend toward larger bone volume (+10 %, p = 0.055) relative to DM women and higher serum sclerostin levels when compared to DM (+31.4 %, p = 0.013), Fx (+25.2 %, p = 0.033), and control (+22.4 %, p = 0.028) subjects.

CONCLUSION

Our data suggest that volumetric bone parameters by QCT and serum sclerostin levels can identify T2D individuals at high risk of fracture and might therefore show promise as clinical tools for fracture risk assessment in T2D. However, future research is needed to establish diabetes-specific QCT- and sclerostin-reference databases.

Collaterals: Implications in cerebral ischemic diseases and therapeutic interventions

Despite the tremendous progress made in the treatment of cerebrovascular occlusive diseases, many patients suffering from ischemic brain injury still experience dismal outcomes. Although rehabilitation contributes to post-stroke functional recovery, there is no doubt that interventions that promote the restoration of blood supply are proven to minimize ischemic injury and improve recovery. In response to the acutely decreased blood perfusion during arterial occlusion, arteriogenesis, the compensation of blood flow through the collateral circulation during arterial obstructive diseases can act not only in a timely fashion but also much more efficiently compared to angiogenesis, the sprouting of new capillaries, and a mechanism occurring in a delayed fashion while increases the total resistance of the vascular bed of the affected territory. Interestingly, despite the vast differences between the two vascular remodeling mechanisms, some crucial growth factors and cytokines involved in angiogenesis are also required for arteriogenesis. Understanding the mechanisms underlying vascular remodeling after ischemic brain injury is a critical step towards the development of effective therapies for ischemic stroke. The present article will discuss our current views in vascular remodeling acutely after brain ischemia, namely arteriogenesis, and some relevant clinical therapies available on the horizon in augmenting collateral flow that hold promise in treating ischemic brain injury. This article is part of a Special Issue entitled SI: Cell Interactions In Stroke.

Plasma levels of matrix metalloproteinase-2, -3, -10, and tissue inhibitor of metalloproteinase-1 are associated with vascular complications in patients with type 1 diabetes: the EURODIAB Prospective Complications Study

BACKGROUND

Impaired regulation of extracellular matrix remodeling by matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase (TIMP) may contribute to vascular complications in patients with type 1 diabetes. We investigated associations between plasma MMP-1, -2, -3, -9, -10 and TIMP-1, and cardiovascular disease (CVD) or microvascular complications in type 1 diabetic patients. We also evaluated to which extent these associations could be explained by low-grade inflammation (LGI) or endothelial dysfunction (ED).

METHODS

493 type 1 diabetes patients (39.5 ± 9.9 years old, 51% men) from the EURODIAB Prospective Complications Study were included. Linear regression analysis was applied to investigate differences in plasma levels of MMP-1, -2, -3, -9, -10, and TIMP-1 between patients with and without CVD, albuminuria or retinopathy. All analyses were adjusted for age, sex, duration of diabetes, Hba1c and additionally for other cardiovascular risk factors including LGI and ED.

RESULTS

Patients with CVD (n = 118) showed significantly higher levels of TIMP-1 [β = 0.32 SD (95%CI: 0.12; 0.52)], but not of MMPs, than patients without CVD (n = 375). Higher plasma levels of MMP-2, MMP-3, MMP-10 and TIMP-1 were associated with higher levels of albuminuria (p-trends were 0.028, 0.004, 0.005 and 0.001, respectively). Severity of retinopathy was significantly associated with higher levels of MMP-2 (p-trend = 0.017). These associations remained significant after further adjustment for markers of LGI and ED.

CONCLUSIONS

These data support the hypothesis that impaired regulation of matrix remodeling by actions of MMP-2, -3 and-10 and TIMP-1 contributes to the pathogenesis of vascular complications in type 1 diabetes.

Central Pulse Pressure and Variability in Matrix Metalloproteinases Genes and Their Inhibitors in Patients With Ischemic Heart Disease

Matrix metalloproteinases (MMPs) as well as their inhibitors (TIMPs) play a crucial role in controlling extracellular matrix turnover and have recently been associated with atherosclerosis, myocardial and vascular injury. Moreover, the genetic variability of MMP genes has been suggested to play an important role in vascular remodeling and age-related arterial stiffening. This study aims to describe associations of 14 selected polymorphisms in genes for MMPs and TIMPs with selected cardiovascular parameters (including central pulse pressure), clinical conditions and drug treatment profiles in 411 stable ischemic patients with preserved systolic function of the left ventricle. The genotyping of 14 single-nucleotide polymorphisms in 8 genes was carried out either using 5′ exonuclease (TaqMan®) reagents or by restriction analysis. Numerous associations of the investigated polymorphisms with systolic and diastolic blood pressure, maximum left ventricular end diastolic pressure and ejection fraction were observed. While some of the observed effects were found to be age-dependent, associations with clinical conditions (hypertension, diabetes mellitus, angina pectoris) were only observed in women and associations with four groups of drugs (statins, nitrates, calcium channel blockers, anti-aggregation drugs) were only observed in men. The results of this study indicate that the genetic variability of MMPs and TIMPs is an important factor which influences cardiovascular functions and may have important consequences for individual therapy customization in the future.

The complementary effects of atorvastatin and exercise treatment on the composition and stability of the atherosclerotic plaques in ApoE knockout mice

Aim

This study aimed to investigate the effects of combined atorvastatin and exercise treatment on the composition and stability of the atherosclerotic plaques in apolipoproteinE (apoE) knockout mice.

Methods

Forty male, apoE^−/− mice were fed a high-fat diet for 16 weeks. Thereafter, while maintained on high-fat diet, they were randomized into four (n = 10) groups for 8 additional weeks: Group CO: Control. Group AT: Atorvastatin treatment (10 mg/Kg/day). Group EX: Exercise-training on treadmill. Group AT+EX: Atorvastatin and simultaneous exercise training. At the study’s end, plasma cholesterol levels, lipids and triglycerides were measured, along with the circulating concentrations of matrix-metalloproteinases (MMP-2,3,8,9) and their inhibitors (TIMP-1,2,3). Plaque area and the relative concentrations of collagen, elastin, macrophages, smooth muscle cells, MMP-2,3,8,9 and TIMP-1,2,3 within plaques were determined. Lastly, MMP activity was assessed in the aortic arch.

Results

All intervention groups showed a lower degree of lumen stenosis, with atheromatous plaques containing more collagen and elastin. AT+EX group had less stenosis and more elastin compared to single intervention groups. MMP-3,-8 -9 and macrophage intra-plaque levels were reduced in all intervention groups. EX group had increased TIMP-1 levels within the lesions, while TIMP-2 was decreased in all intervention groups. The blood levels of the above molecules increased during atherosclerosis development, but they did not change after the therapeutic interventions in accordance to their intra-plaque levels.

Conclusion

The two therapeutic strategies act with synergy regarding the extent of the lesions and lumen stenosis. They stabilize the plaque, increasing its content in elastin and collagen, by influencing the MMP/TIMP equilibrium, which is mainly associated with the macrophage amount. While the increased MMP-2,-3,-8 -9, as well as TIMP-1 and TIMP-2 circulating levels are markers of atherosclerosis, they are not correlated with their corresponding concentrations within the lesions after the therapeutic interventions, and cannot serve as markers for the disease development/amelioration.

Matrix metalloproteinases: potential therapeutic target for diabetic neuropathic pain

INTRODUCTION

MMPs are zinc-dependent endopeptidases that play a key role in the remodeling of extracellular matrix (ECM). Various pathogenic mediators trigger abnormal MMP activity that leads to ECM abnormality. Hyperglycemia is one of the strong stimuli among oxidative stress and inflammation that upregulate MMP expression in the central and peripheral nervous system. MMP-mediated ECM abnormality hypersensitizes peripheral as well as central nerves that precipitate neuropathic pain in diabetic patients.

AREAS COVERED

Molecular mechanisms associated with MMP-mediated diabetic neuropathic pain have been discussed. Various endogenous, natural and synthetic MMP inhibitors are also explored.

EXPERT OPINION

In diabetes, hyperglycemia activates MMPs that along with the other pathogenic mediators cause neuronal injury and precipitates neuropathic pain. Thus, MMPs play a crucial role in the development of neuropathic pain among diabetics. However, MMPs are not only responsible for deleterious ECM abnormalities but are also required for beneficial remodeling of ECM under normal physiological conditions. Therefore, highly selective and specific inhibitors must be designed and explored for their clinical potential for treatment/prevention of diabetic neuropathic pain.

Regulatory mechanism of gallic acid against advanced glycation end products induced cardiac remodeling in experimental rats

Advanced glycation end products (AGEs) play a major role in the development of cardiovascular disorders in diabetic patients. Recent studies evidenced the beneficial role of phytochemicals in reducing the risk of cardiovascular diseases. Hence the present study was framed to investigate the protective role of Gallic acid (GA) on AGEs induced cardiac fibrosis. Rats were infused with in vitro prepared AGEs (50mg/kg BW-intravenous injection) for 30 days. Further, GA (25mg/kgBW) was administered to rats along with AGEs. On infusion of AGEs, induction of fibrotic markers, collagen deposition, oxidative marker NADPH oxidase (NOX-p47 phox subunit), AGE receptor (RAGE) and cytokines expression was evaluated in the heart tissues using RT-PCR, Western blot and immunostaining methods. AGEs infusion significantly (P<0.01) increased the HW/BW ratio and fibrosis (4-fold) with increased expression of matrix genes MMP-2 and -9 (P<0.01, respectively) in the heart tissues. Whereas, administration of GA along with AGEs infusion prevented the fibrosis induced by AGEs. Further, GA treatment effectively prevented the AGEs mediated up-regulation of pro-fibrotic genes and ECM proteins such as TNF-α, TGF-β, MMP-2 and -9 expression. In addition, the increased expression of NOX (P<0.01), RAGE (P<0.01), NF-κB (P<0.01) and ERK 1/2 on AGEs infusion were normalized by GA treatment. Thus the present study shows the protective effect of GA on the fibrotic response and cardiac remodeling process induced by advanced glycation end products from external sources.

Vascular remodeling after ischemic stroke: mechanisms and therapeutic potentials

The brain vasculature has been increasingly recognized as a key player that directs brain development, regulates homeostasis, and contributes to pathological processes. Following ischemic stroke, the reduction of blood flow elicits a cascade of changes and leads to vascular remodeling. However, the temporal profile of vascular changes after stroke is not well understood. Growing evidence suggests that the early phase of cerebral blood volume (CBV) increase is likely due to the improvement in collateral flow, also known as arteriogenesis, whereas the late phase of CBV increase is attributed to the surge of angiogenesis. Arteriogenesis is triggered by shear fluid stress followed by activation of endothelium and inflammatory processes, while angiogenesis induces a number of pro-angiogenic factors and circulating endothelial progenitor cells (EPCs). The status of collaterals in acute stroke has been shown to have several prognostic implications, while the causal relationship between angiogenesis and improved functional recovery has yet to be established in patients. A number of interventions aimed at enhancing cerebral blood flow including increasing collateral recruitment are under clinical investigation. Transplantation of EPCs to improve angiogenesis is also underway. Knowledge in the underlying physiological mechanisms for improved arteriogenesis and angiogenesis shall lead to more effective therapies for ischemic stroke.