Matrix metalloproteinase-2 dysregulation in type 1 diabetes

Plasma matrix metalloproteinases and tissue inhibitors of metalloproteinases explored in relation to the severity and progression of diabetic retinopathy in patients with type 1 diabetes: baseline and prospective analyses

AIMS

To explore whether circulating matrix metalloproteinase-2 (MMP-2), MMP-9, MMP-9/neutrophil gelatinase-associated lipocalin, MMP-9/tissue inhibitor of metalloproteinase-1 (TIMP-1), MMP-14, TIMP-2 and TIMP-3 were associated with the severity and progression of diabetic retinopathy (DR) in patients with type 1 diabetes (T1D).

METHODS

Baseline and prospective analyses were conducted over a period of 10.5 person-years. In 2009, recruitment and biochemical analyses (MMPs, TIMPs, glycated haemoglobin (HbA1c), serum creatinine, macroalbuminuria) were performed. Fundus photography, performed at baseline and at follow-up in accordance with the regional screening programme, was compared after being categorised according to the International Clinical Diabetic Retinopathy Disease Severity Scale. 'DR progression at least one leve' was calculated. High MMP-2 was defined as ≥178 ng/mL (≥75th percentile) and high TIMP-2 as ≥205 ng/mL (≥75th percentile). DR was dichotomised as 'at least moderate DR' or 'no/mild DR'.

RESULTS

The study included 267 participants, 57% of whom were men. At baseline, the prevalence of high MMP-2 (p=0.001) and high TIMP-2 (p=0.008) increased with the severity of DR. 'At least moderate DR' (adjusted OR (AOR) 2.4, p=0.008) and macroalbuminuria (AOR 3.6, p=0.025) were independently associated with high MMP-2. 'At least moderate DR' (AOR 2.3, p=0.009) and macroalbuminuria (3.4, p=0.031) were independently associated with high TIMP-2. DR progression occurred in 101 (46%) patients (p<0.001). HbA1c≥53 mmol/mol was associated with the progression of DR (crude OR 3.8, p=0.001). No other MMPs or TIMPs were linked to the severity or the progression of DR.

CONCLUSIONS

High levels of MMP-2 and TIMP-2 indicated more severe DR or diabetic nephropathy. Only HbA1c was associated with the progression of DR in 267 patients with T1D.

Improvement effects of transplanting pancreatic islet that previously incubated with biomaterials on the diabetic nephropathy in STZ- diabetic rats

BACKGROUND

Islet transplantation is an effective treatment for diabetes or even its complications. Aim of this study is to investigate efficacy of biomaterial treated islet transplantation on treating diabetic nephropathy.

METHODS

Male rats were randomly divided into 6 groups; Control, diabetic control, diabetic transplanted with untreated islets, with platelet rich plasma treated islets, with pancreatic islets homogenate treated islets, or with these biomaterials combination treated islets. Islets cultured with biomaterials and transplanted to diabetic rats. After 60 days, biochemical, oxidative stress, and stereological parameters were assessed.

RESULTS

Serum albumin and BUN concentration, decreased and increased respectively, Oxidative stress of kidney impaired, kidney weight, volume of kidney, cortex, medulla, glomerulus, proximal and distal tubules, collecting ducts, vessels, inflammatory, necrotic and fibrotic tissue in diabetic group increased compared to control group (p < 0.001). In treated groups, especially pancreatic islets homogenate treated islets transplanting animals, there was significant changes in kidney weight, and volume of kidney, proximal and distal tubules, Henle's loop and collecting ducts compared with diabetic group (p = 0.013 to p < 0.001). Combination treated islets animals showed significant increase in vessel volume compared to diabetic group (p < 0.001). Necrotic and fibrotic tissue significantly decreased in islets treated than untreated islet animals, it was higher in pancreatic islets homogenate, and combination treated islets groups (p = 0.001).

CONCLUSIONS

Biomaterials treated islets transplanting could improve diabetic nephropathy. Improvement of oxidative stress followed by controlling glucose level, and effects of growth factors presenting in biomaterials can be considered as capable underlying mechanism of ameliorating inflammatory, necrotic and fibrotic tissue volume.

Knockout of Matrix Metalloproteinase 2 Opposes Hypertension- and Diabetes-induced Nephropathy

ABSTRACT

The progression of chronic kidney disease results from the accumulation of extracellular matrix leading to end-stage renal disease. We previously demonstrated that a broad-spectrum matrix metalloproteinase (MMP) inhibitor reduced renal injury in rat models of hypertension and diabetes. However, the isoforms and mechanisms involved are unclear. This study examined the role of MMP2 during the development of proteinuria and renal injury after induction of hypertension or diabetes in Dahl salt-sensitive (SS) and MMP2 knockout (KO) rats. Mean arterial pressure rose from 115 ± 2 to 145 ± 2 mm Hg and 116 ± 1 to 152 ± 3 mm Hg in MMP2 KO and SS rats fed a high-salt (8% NaCl) diet for 3 weeks. The degree of proteinuria, glomerular injury, renal fibrosis, and podocyte loss was lower in MMP2 KO rats than in SS rats. Blood glucose and HbA1c levels, and mean arterial pressure rose to the same extent in streptozotocin-treated SS and MMP2 KO rats. However, the degree of proteinuria, glomerulosclerosis, renal fibrosis, renal hypertrophy, glomerular permeability to albumin, and the renal expression of MMP2 and TGFβ1 were significantly reduced in MMP2 KO rats. Glomerular filtration rate fell by 33% after 12 weeks of diabetes in streptozotocin-treated SS rats compared with time-control rats, but glomerular filtration rate only fell by 12% in MMP2 KO rats. These results indicate that activation of MMP2 plays an essential role in the pathogenesis of hypertensive and diabetic nephropathy and suggests that an MMP2 inhibitor might slow the progression of chronic kidney disease.

Coupling hCG-based protease sensors with a commercial pregnancy test strip for simple analyses of protease activities

Proteases play an essential role in many cellular processes, and consequently, abnormalities in their activities are related to various diseases. Methods have been developed to measure the activity of these enzymes, but most involve sophisticated instruments or complicated procedures, which hampers the development of a point-of-care test (POCT). Here, we propose a strategy for developing simple and sensitive methods to analyze protease activity using commercial pregnancy test strips that detect human chorionic gonadotropin (hCG). hCG was engineered to have site-specific conjugated biotin and a peptide sequence, which can be cleaved by a target protease, between hCG and biotin. hCG protein was immobilized on streptavidin-coated beads, resulting in a protease sensor. The hCG-immobilized beads were too large to flow through the membrane of the hCG test strip and yielded only one band in the control line. When the peptide linker was hydrolyzed by the target protease, hCG was released from the beads, and the signal appeared in both the control and test lines. Three protease sensors for matrix metalloproteinase-2, caspase-3, and thrombin were constructed by replacing the protease-cleavable peptide linker. The combination of the protease sensors and a commercial pregnancy strip enabled the specific detection of each protease in the picomolar range, with a 30-min incubation of the hCG-immobilized beads and samples. The modular design of the protease sensor and simple assay procedure will facilitate the development of POCTs for various protease disease markers.

Diabetic Nephropathy and Gaseous Modulators

Diabetic nephropathy (DN) remains the leading cause of vascular morbidity and mortality in diabetes patients. Despite the progress in understanding the diabetic disease process and advanced management of nephropathy, a number of patients still progress to end-stage renal disease (ESRD). The underlying mechanism still needs to be clarified. Gaseous signaling molecules, so-called gasotransmitters, such as nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H₂S), have been shown to play an essential role in the development, progression, and ramification of DN depending on their availability and physiological actions. Although the studies on gasotransmitter regulations of DN are still emerging, the evidence revealed an aberrant level of gasotransmitters in patients with diabetes. In studies, different gasotransmitter donors have been implicated in ameliorating diabetic renal dysfunction. In this perspective, we summarized an overview of the recent advances in the physiological relevance of the gaseous molecules and their multifaceted interaction with other potential factors, such as extracellular matrix (ECM), in the severity modulation of DN. Moreover, the perspective of the present review highlights the possible therapeutic interventions of gasotransmitters in ameliorating this dreaded disease.

Long-Term Neuromodulatory Effects of Repetitive Transcranial Magnetic Stimulation (rTMS) on Plasmatic Matrix Metalloproteinases (MMPs) Levels and Visuospatial Abilities in Mild Cognitive Impairment (MCI)

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation technique that is used against cognitive impairment in mild cognitive impairment (MCI) and Alzheimer's disease (AD). However, the neurobiological mechanisms underlying the rTMS therapeutic effects are still only partially investigated. Maladaptive plasticity, glial activation, and neuroinflammation, including metalloproteases (MMPs) activation, might represent new potential targets of the neurodegenerative process and progression from MCI to AD. In this study, we aimed to evaluate the effects of bilateral rTMS over the dorsolateral prefrontal cortex (DLPFC) on plasmatic levels of MMP1, -2, -9, and -10; MMPs-related tissue inhibitors TIMP1 and TIMP2; and cognitive performances in MCI patients. Patients received high-frequency (10 Hz) rTMS (MCI-TMS, n = 9) or sham stimulation (MCI-C, n = 9) daily for four weeks, and they were monitored for six months after TMS. The plasmatic levels of MMPs and TIMPs and the cognitive and behavioral scores, based on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Beck Depression Inventory II, Beck Anxiety Inventory, and Apathy Evaluation Scale, were assessed at baseline (T0) and after 1 month (T1) and 6 months (T2) since rTMS. In the MCI-TMS group, at T2, plasmatic levels of MMP1, -9, and -10 were reduced and paralleled by increased plasmatic levels of TIMP1 and TIMP2 and improvement of visuospatial performances. In conclusion, our findings suggest that targeting DLPFC by rTMS might result in the long-term modulation of the MMPs/TIMPs system in MCI patients and the neurobiological mechanisms associated with MCI progression to dementia.

Molecular profiling of urinary extracellular vesicles in chronic kidney disease and renal fibrosis

Chronic kidney disease (CKD) is a long-term kidney damage caused by gradual loss of essential kidney functions. A global health issue, CKD affects up to 16% of the population worldwide. Symptoms are often not apparent in the early stages, and if left untreated, CKD can progress to end-stage kidney disease (ESKD), also known as kidney failure, when the only possible treatments are dialysis and kidney transplantation. The end point of nearly all forms of CKD is kidney fibrosis, a process of unsuccessful wound-healing of kidney tissue. Detection of kidney fibrosis, therefore, often means detection of CKD. Renal biopsy remains the best test for renal scarring, despite being intrinsically limited by its invasiveness and sampling bias. Urine is a desirable source of fibrosis biomarkers as it can be easily obtained in a non-invasive way and in large volumes. Besides, urine contains biomolecules filtered through the glomeruli, mirroring the pathological state. There is, however, a problem of highly abundant urinary proteins that can mask rare disease biomarkers. Urinary extracellular vesicles (uEVs), which originate from renal cells and carry proteins, nucleic acids, and lipids, are an attractive source of potential rare CKD biomarkers. Their cargo consists of low-abundant proteins but highly concentrated in a nanosize-volume, as well as molecules too large to be filtered from plasma. Combining molecular profiling data (protein and miRNAs) of uEVs, isolated from patients affected by various forms of CKD, this review considers the possible diagnostic and prognostic value of uEVs biomarkers and their potential application in the translation of new experimental antifibrotic therapeutics.

Elevated IgG and IgM Autoantibodies to Advanced Glycation End Products of Vascular Elastin in Hypertensive Patients with Type 2 Diabetes: Relevance to Disease Initiation and Progression

The increased glycation of elastin is an important factor in vascular changes in diabetes. Using the ELISA method, we determined serum levels of IgM and IgG autoantibodies to advanced glycation end products of vascular elastin (anti-AGE EL IgM and anti-AGE EL IgG) in 59 hypertensive patients with type 2 diabetes (T2D) and 20 healthy controls. Serum levels of matrix metalloproteinases-2 and -9 (MMP-2 and MMP-9) and the C-reactive protein (CRP) were also determined. The levels of anti-AGE EL IgM antibodies in the T2D group were similar to those in the control group, while those of anti-AGE EL IgG antibodies were significantly higher (p = 0.017). Significant positive correlations were found between the levels of anti-AGE EL IgM antibodies and MMP-2 (r = 0.322; p = 0.013) and between the levels of anti-AGE EL IgG antibodies and CRP (r = 0.265; p = 0.042). Our study showed that elevated anti-AGE EL IgG antibody levels may be an indicator of the enhanced AGE-modification and inflammatory-mediated destruction of vascular elastin in hypertensive patients with T2D. Anti-AGE EL IgM antibodies may reflect changes in vascular MMP-2 activity, and their elevated levels may be a sign of early vascular damage.

Anti-Hyperglycemic Effect of Magnesium-Enhanced Alkaline-Reduced Water on High Glucose-Induced Oxidative Stress in Renal Tubular Epithelial Cells

Diabetes is coupled with hyperglycemia, a state in which elevated glucose levels trigger oxidative stress (OS) in various body functions. One of the organs most afflicted by diabetes is the kidney. Despite this, specific treatments to mitigate the harmful effects of hyperglycemia-induced OS in the kidney have not been extensively explored. This study evaluates the anti-hyperglycemic efficacy of magnesium-enhanced alkaline-reduced water (MARW) in human kidney-2 (HK-2) cells. OS, mitogen-activated protein kinase (MAPK) signaling and fibrosis markers were assessed in high glucose (HG)-induced HK-2 cells, followed by treatment with experimental water for 24 h. Surprisingly, MARW rescued the vitality of HG-induced HK-2 cells, in contrast to that seen with other experimental waters. Additionally, MARW maintained reactive oxygen species, nitric oxide, catalase, glutathione peroxidase, hepatocyte growth factor and glucose uptake in HG-induced HK-2 cells but not in tap water and mineral water. Similarly, MARW downregulated the expression of MAPK and fibrosis-linked signaling proteins such as p-p38, phospho-c-Jun N-terminal kinase, α-smooth muscle actin, matrix metalloproteinase-3 and cleaved caspase 3 in HG-induced HK-2 cells. In conclusion, MARW protects HK-2 cells from the deleterious effects of HG by stabilizing antioxidant defenses and by signaling cascades related to metabolism, apoptosis and fibrosis.

Swimming training modulates lung injury induced by ovariectomy in diabetic rats: involvement of inflammatory and fibrotic biomarkers

CONTEXT

Previous studies have noted that the incidence of inflammatory and fibrotic diseases is higher in diabetic menopausal women.

OBJECTIVE

In the present study, we evaluated effects of swimming training on inflammatory and fibrotic biomarkers in the lung of ovariectomized diabetic rats.

MATERIALS AND METHODS

Forty female rats were assigned into four groups: sham; rats underwent surgery without ovariectomies, OVX: rats that underwent ovariectomies, OVX.Dia: ovariectomized rats with high-fat diet, OVX.Dia. Exe: ovariectomized diabetic rats with 8 weeks of swimming training. At the end of experiment, protein expressions were assessed with western blot. Lung sections were subjected to immunohistochemical and haematoxylin eosin staining.

RESULTS

There was a significant difference in the protein expressions between exercise and ovariectomized diabetic groups (p < .05).

CONCLUSION

The present study showed strong potential of swimming training on oestrogen deficient diabetic lung. These data encourage further investigation into the inclusive effects of exercise in menopausal diabetic women.

Adiponectin accumulation in the retinal vascular endothelium and its possible role in preventing early diabetic microvascular damage

Adiponectin (APN), a protein abundantly secreted from adipocytes, has been reported to possess beneficial effects on cardiovascular diseases in association with its accumulation on target organs and cells by binding to T-cadherin. However, little is known about the role of APN in the development of diabetic microvascular complications, such as diabetic retinopathy (DR). Here we investigated the impact of APN on the progression of early retinal vascular damage using a streptozotocin (STZ)-induced diabetic mouse model. Our immunofluorescence results clearly showed T-cadherin-dependent localization of APN in the vascular endothelium of retinal arterioles, which was progressively decreased during the course of diabetes. Such reduction of retinal APN accompanied the early features of DR, represented by increased vascular permeability, and was prevented by glucose-lowering therapy with dapagliflozin, a selective sodium-glucose co-transporter 2 inhibitor. In addition, APN deficiency resulted in severe vascular permeability under relatively short-term hyperglycemia, together with a significant increase in vascular cellular adhesion molecule-1 (VCAM-1) and a reduction in claudin-5 in the retinal endothelium. The present study demonstrated a possible protective role of APN against the development of DR.

Matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases in kidney disease

Matrix metalloproteinases (MMPs) are a group of zinc and calcium endopeptidases which cleave extracellular matrix (ECM) proteins. They are also involved in the degradation of cell surface components and regulate multiple cellular processes, cell to cell interactions, cell proliferation, and cell signaling pathways. MMPs function in close interaction with the endogenous tissue inhibitors of matrix metalloproteinases (TIMPs), both of which regulate cell turnover, modulate various growth factors, and participate in the progression of tissue fibrosis and apoptosis. The multiple roles of MMPs and TIMPs are continuously elucidated in kidney development and repair, as well as in a number of kidney diseases. This chapter focuses on the current findings of the significance of MMPs and TIMPs in a wide range of kidney diseases, whether they result from kidney tissue changes, hemodynamic alterations, tubular epithelial cell apoptosis, inflammation, or fibrosis. In addition, the potential use of these endopeptidases as biomarkers of renal dysfunction and as targets for therapeutic interventions to attenuate kidney disease are also explored in this review.

Cardiac extracellular matrix modulation in a rat-diabetic model: biochemical and anti-oxidant beneficial effect of pomegranate (Punica granatum) peel extract

CONTEXT

Disorders associated with diabetes and the beneficial effects of pomegranate peel extract (PPE) were widely reported. However effect of diabetes and PPE on extracellular matrix (ECM) remodelling needs further investigation.

OBJECTIVES

The focus of this study was to investigate the involvement of diabetes in cardiac ECM and the beneficial effects of PPE.

METHODS

Diabetes was induced by alloxan. PPE group was injected with 100 mg/kg of PPE. The phenolic profile of PPE was analyzed by HPLC. ECM was detected by ELISA. MMP-1, -8, -13 were determined by a colorimetric assay.

RESULTS

Compared to control fibronectin and laminin plasma content was higher respectively by 69% and 42% (p < 0.05) in diabetes. LV content of hydroxyproline and total collagen was higher by 195% (p < 0.01) and 56% (p < 0.05) in the diabetic group compared to control and restored at a similar level to controls in the PPE group. Compared to control, collagenase activity was significantly reduced by 32% (p < 0.05) and 35% (p < 0.05) respectively in ALX and PPF groups. There is no significant difference in collagenase activities in diabetic rats after and before PPE injection.

CONCLUSION

Diabetes is involved in cardiac ECM remodelling which can be improved by PPE. These findings will be useful for more understanding diabetes-induced cardiac disorders.

Herbal Infusions as a Valuable Functional Food

Herbal infusions are an underestimated and easy to intake a source of biologically active natural compounds (polyphenols), which, in the dissolved form, are more easily absorbed. Therefore, this study aimed to assess the potential of herbal infusions as a functional food to reduce postprandial hyperglycemia (inhibition of α-amylase and α-glucosidase) and to reduce the effects of increased blood glucose level (antioxidant effect-DPPH, CUPRAC, and Fe²⁺ chelating assays, as well as anti-inflammatory activity-inhibition of collagenase). We showed that polyphenols are present in the examined aqueous herbal infusions (including chlorogenic and gallic acids). Subsequently, our research has shown that herbal infusions containing cinnamon bark, mulberry leaves, and blackberry fruits most strongly inhibit glucose release from complex carbohydrates, and that all herbal infusions can, to different degrees, reduce the effects of elevated blood sugar. In conclusion, infusions prepared from herbal blends could be recommended to prevent type II diabetes.

Galectin-3, metalloproteinase-2 and cardiovascular disease were independently associated with metalloproteinase-14 in patients with type 1 diabetes: a cross sectional study

BACKGROUND

Type 1 diabetes (T1D) is a major risk factor for cardiovascular disease (CVD). Matrix metalloproteinase-14 (MMP-14) is involved in the development of atherosclerosis and CVD. The main aim was to explore the associations between MMP-14 and selected inflammatory and metabolic variables, CVD, depression, physical activity, smoking and medication in patients with T1D. The secondary aim was to explore associations with CVD.

METHODS

Cross-sectional design. The participants were consecutively recruited from one specialist diabetes out-patient clinic. Depression was assessed by a self-report instrument. Blood samples, anthropometrics and blood pressure were collected, supplemented with data from electronic health records. High MMP-14 was defined as  ≥  5.81 ng/mL. Non-parametric tests, Chi² tests and multiple logistic regression analyses were performed.

RESULTS

Two hundred and sixty-eighth T1D patients aged 18-59 years participated (men 58%, high MMP-14 25%, CVD 3%). Sixty-seven patients with high MMP-14, compared to 201 patients with lower MMP-14, had higher prevalence of CVD (8% versus 1%, p  =  0.012), and had higher levels of galectin-3 (p  <  0.001) and MMP-2 (p  =  0.018). Seven patients with CVD, compared to 261 without, were older (p  =  0.003), had longer diabetes duration (p  =  0.027), and had higher prevalence of high MMP-14 (71% versus 24%, p  =  0.012), abdominal obesity (p  =  0.014), depression (p  =  0.022), usage of antidepressants (p  =  0.008), antihypertensive drugs (p  =  0.037) and statins (p  =  0.049). Galectin-3 (per ng/mL) [adjusted odds ratio (AOR) 2.19, p  <  0.001], CVD (AOR 8.1, p  =  0.027), and MMP-2 (per ng/mL) (AOR 1.01, p  =  0.044) were associated with high MMP-14. Depression (AOR 17.4, p  =  0.006), abdominal obesity (15.8, p  =  0.006), high MMP-14 (AOR 14.2, p  =  0.008), and diabetes duration (AOR 1.10, p  =  0.012) were associated with CVD.

CONCLUSIONS

The main findings of this study were that galecin-3, MMP-2, and CVD were independently associated with high levels of MMP-14 in T1D patients. The association between MMP-14 and galectin-3 is a new finding. No traditional risk factors for CVD were associated with MMP-14. Depression, abdominal obesity and MMP-14 were independently associated with CVD.

Serum Anti-Collagen IV IgM and IgG Antibodies as Indicators of Low Vascular Turnover of Collagen IV in Patients with Long-Term Complications of Type 2 Diabetes

Thickening of the vascular basement membrane (BM) is a fundamental structural change in the small blood vessels in diabetes. Collagen type IV (CIV) is a major component of the BMs, and monitoring the turnover of this protein in type 2 diabetes (T2D) can provide important information about the mechanisms of vascular damage. The aim of the study was through the use of non-invasive biomarkers of CIV (autoantibodies, derivative peptides, and immune complexes) to investigate vascular turnover of CIV in patients with long-term complications of T2D. We measured serum levels of these biomarkers in 59 T2D patients with micro- and/or macrovascular complications and 20 healthy controls using an ELISA. Matrix metalloproteinases-2 and -9 (MMP-2 and MMP-9) were also tested. In the T2D group, significantly lower levels of CIV markers and significantly higher levels of MMP-2 and MMP-9 were found compared to controls. A significant positive correlation was found between IgM antibody levels against CIV and MMP-2. These findings suggest that vascular metabolism of CIV is decreased in T2D with long-term complications and show that a positive linear relationship exists between MMP-2 levels and CIV turnover in the vascular wall.

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.

Joint Entropy-Assisted Graphene Oxide-Based Multiplexing Biosensing Platform for Simultaneous Detection of Multiple Proteases

Due to the limited clinical utility of individual biomarkers, there is growing recognition of the need for combining multiple biomarkers as a panel to improve the accuracy and efficacy of disease diagnosis and prognosis. The conventional method to detect multiple analyte species is to construct a sensor array, which consists of an array of individual selective probes for different species. In this work, by using cancer biomarker matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinases (ADAMs) as model analytes and functionalized nanographene oxide (nGO) as a sensing element, we developed a multiplexing fluorescence sensor in a nonarray format for simultaneous measurement of the activities of multiple proteases. The constructed nGO-based biosensor was rapid, sensitive, and selective and was also utilized for the successful profiling of ADAMs/MMPs in simulated serum samples. Furthermore, we showed that joint entropy and programming could be utilized to guide experiment design, especially in terms of the selection of a subset of proteases from the entire MMPs/ADAMs family as an appropriate biomarker panel. Our developed nGO-based multiplex sensing platform should find useful application in early cancer detection and diagnosis.

Subgingival endotoxin and lipoteichoic acid modulate cytokine production in diabetic subjects: A Case-control Study

BACKGROUND

Periodontal disease and diabetes mellitus (DM) are highly prevalent and interrelated diseases, resulting in altered host response microbiota. Thus, this study aimed to evaluate the impact of DM on local levels of lipopolysaccharide (LPS) and lipoteichoic acid (LTA) and their relationship with cytokines and matrix metalloproteinases' (MMPs) profile.

METHODS

This case-control study included diabetic (n = 15) and non-diabetic (n = 15) subjects presenting Stage 3-4, Grade C, Periodontitis. Gingival crevicular fluid (GCF) was collected, and LPS and LTA levels were analyzed by enzyme-linked immunosorbent assay (ELISA), while IFN-γ, IL-10, IL-17, IL-1β, IL-4, MMP-2, and MMP-9 were measured by LUMINEX/MAGpix. Mann-Whitney and Spearman's correlation tests were used to compared and to correlate variables (p < 0.05).

RESULTS

Higher levels of LTA, LPS, IL-10, IL-1β, and MMP-2 (p < 0.05) and lower levels of IL-17 were found in the DM group (p < 0.05). Non-diabetic subjects presented higher LPS, IFN-γ, IL-17, and MMP-2 levels and lower IL-10 concentration (p < 0.05). No significant correlation was seen between LPS and cytokine profile in non-diabetic. Local levels of LTA were positively correlated with IL-17 and MMP-2 and negatively with IL-10.

CONCLUSION

LTA and LPS drove the inflammatory profile through the modulation of cytokines and MMPs in a different manner in DM and non-diabetic subjects.

Suppressed immune profile in children with combined type 1 diabetes and celiac disease

Children diagnosed with a combination of type 1 diabetes (T1D) and celiac disease (CD) show a dysregulated T helper type 1 (Th1)/Th17 response. Besides the cellular involvement, several soluble immune markers are involved in the autoimmune process of both T1D and CD. Only few studies have examined the peripheral pattern of different cytokines, chemokines and acute-phase proteins (APP) in children with combined T1D and CD. To our knowledge, no studies have evaluated the serum levels of adipocytokines and matrix metalloproteinases (MMPs) in this context. The purpose of the present study was to acquire more knowledge and to gain deeper understanding regarding the peripheral immunoregulatory milieu in children with both T1D and CD. The study included children diagnosed with both T1D and CD (n = 18), children with T1D (n = 27) or CD (n = 16) and reference children (n = 42). Sera were collected and analysis of 28 immune markers (cytokines, chemokines, APPs, adipocytokines and MMPs) was performed using the Luminex technique. The major findings showed that children with a double diagnosis had lower serum levels of interleukin (IL)-22, monocyte chemoattractant protein (MIP)-1α, monocyte chemoattractant protein (MCP)-1, procalcitonin, fibrinogen, visfatin and matrix metalloproteinase (MMP)-2. These results indicate a suppressed immune profile in children with combined T1D and CD, including Th17 cytokines, chemokines, APPs, adipocytokines and MMPs. We conclude that, besides cytokines and chemokines, other immune markers, e.g. APPs, adipocytokines and MMPs, are of importance for further investigations to elucidate the heterogeneous immune processes present in patients diagnosed with T1D in combination with CD.

Selected Metal Matrix Metalloproteinases and Tissue Inhibitors of Metalloproteinases as Potential Biomarkers for Tubulointerstitial Fibrosis in Children with Unilateral Hydronephrosis

Renal tubulointerstitial fibrosis caused by congenital ureteropelvic junction obstruction (UPJO) may lead to the development of obstructive nephropathy (ON) and the impairment of kidney function. Hence, the identification of early biomarkers of this condition might be of assistance in therapeutic decisions. This study evaluates serum and urinary metalloproteinases MMP-1, MMP-2, and MMP-9 and tissue inhibitors of metalloproteinases TIMP-1 and TIMP-2 as potential biomarkers of ON in children with congenital unilateral hydronephrosis (HN) caused by UPJO. Forty-five (45) children with congenital HN of different grades of severity and twenty-one (21) healthy controls were enrolled in the study. Urinary and serum concentrations of MMP-1, MMP-2, MMP-9, TIMP-1 and TIMP-2 were measured using specific ELISA kits. The urinary excretions were expressed as biomarker/creatinine (Cr) ratios. To evaluate the extracellular matrix remodelling process activity, the serum and urinary MMP-1, -2, -9/TIMP-1, -2 ratios were also calculated. In comparison with the controls, patients with HN, independent of the grade, showed significantly increased median serum MMP-9, TIMP-1, and TIMP-2, median urinary MMP-9/Cr, and TIMP-2/Cr ratios. Lower median values of serum MMP-2/TIMP-1, MMP-9/TIMP-1 in patients with HN were also revealed. Additionally, higher urinary MMP-2/Cr, lower urinary MMP-2/TIMP-2, and lower serum MMP-9/TIMP-2 ratios were observed in patients with HN grades 3 and 4. Patients with ON diagnosed by renal scintigraphy had a significantly higher median serum MMP-9 concentration and lower median serum MMP-9/TIMP-1, -2 ratios in comparison with those without this condition. Patients with nonglomerular proteinuria had a significantly higher median serum TIMP-1 concentration, a higher median urinary TIMP-2/Cr ratio, and a lower serum MMP-9/TIMP-1 ratio compared to those without this symptom. The relationship between the measured biomarkers and the relative function of the obstructed kidney showed no correlations. The ROC curve analysis showed a promising diagnostic profile for the detection of ON for serum MMP-9 and the serum MMP-9/TIMP-1 and MMP-9/TIMP-2 ratios. In conclusion, the results of this study suggest that patients with HN, particularly with grades 3 and 4, are at higher risk of renal tubulointerstitial fibrosis. The noninvasive markers of this condition considered are urinary MMP-2/Cr and MMP-9/Cr, serum MMP-9, serum and urinary MMP-2, MMP-9/TIMP-1, -2. Additionally, serum MMP-9 and MMP-9/TIMP-1, -2 may become promising markers of ON.

Use of Glycated Hemoglobin (A1c) as a Biomarker for Vascular Risk in Type 2 Diabetes: Its Relationship with Matrix Metalloproteinases-2, -9 and the Metabolism of Collagen IV and Elastin

Background and objectives: HbA1c measurements may be useful not only in optimizing glycemic control but also as a tool for managing overall vascular risk in patients with diabetes. In the present study, we investigate the clinical significance of HbA1c as a biomarker for hyperglycemia-induced vascular damages in type 2 diabetes (T2D) based on the levels of matrix metalloproteinases-2, -9 (MMP-2, MMP-9), anti-collagen IV (ACIV), and anti-elastin (AE) antibodies (Abs) IgM, IgG, and IgA, and CIV-derived peptides (CIV-DP) reflecting collagen and elastin turnover in the vascular wall. The aim is to show the relationship of hyperglycemia with changes in the levels of vascular markers and the dynamics of this relationship at different degrees of glycemic control reported by HbA1c levels. Materials and Methods: To monitor elastin and collagen IV metabolism, we measured serum levels of these immunological markers in 59 patients with T2D and 20 healthy control subjects with an ELISA. Results: MMP-2, MMP-9, and the AEAbs IgA levels were significantly higher in diabetic patients than in control subjects, whereas those of the AEAbs IgM, ACIVAbs IgM, and CIV-DP were significantly lower. MMP-9 levels were significantly lower at HbA1c values >7.5%. Conclusions: A set of three tested markers (MMP-2, MMP-9, and AEAbs IgA) showed that vascular damages from preceding long-term hyperglycemia begin to dominate at HbA1c values ≥7.5%, which is the likely cut-point to predict increased vascular risk.

Blocking matrix metalloproteinase-mediated syndecan-4 shedding restores the endothelial glycocalyx and glomerular filtration barrier function in early diabetic kidney disease

The endothelial glycocalyx is a key component of the glomerular filtration barrier. We have shown that matrix metalloproteinase (MMP)-mediated syndecan 4 shedding is a mechanism of glomerular endothelial glycocalyx damage in vitro, resulting in increased albumin permeability. Here we sought to determine whether this mechanism is important in early diabetic kidney disease, by studying streptozotocin-induced type 1 diabetes in DBA2/J mice. Diabetic mice were albuminuric, had increased glomerular albumin permeability and endothelial glycocalyx damage. Syndecan 4 mRNA expression was found to be upregulated in isolated glomeruli and in flow cytometry-sorted glomerular endothelial cells. In contrast, glomerular endothelial luminal surface syndecan 4 and Marasmium oreades agglutinin lectin labelling measurements were reduced in the diabetic mice. Similarly, syndecan 4 protein expression was significantly decreased in isolated glomeruli but increased in plasma and urine, suggesting syndecan 4 shedding. Mmp-2, 9 and 14 mRNA expression were upregulated in isolated glomeruli, suggesting a possible mechanism of glycocalyx damage and albuminuria. We therefore characterised in detail the activity of MMP-2 and 9 and found significant increases in kidney cortex, plasma and urine. Treatment with MMP-2/9 inhibitor I for 21 days, started six weeks after diabetes induction, restored endothelial glycocalyx depth and coverage and attenuated diabetes-induced albuminuria and reduced glomerular albumin permeability. MMP inhibitor treatment significantly attenuated glomerular endothelial and plasma syndecan 4 shedding and inhibited plasma MMP activity. Thus, our studies confirm the importance of MMPs in endothelial glycocalyx damage and albuminuria in early diabetes and demonstrate that this pathway is amenable to therapeutic intervention. Hence, treatments targeted at glycocalyx protection by MMP inhibition may be of benefit in diabetic kidney disease.

The Effect of Nano-Epigallocatechin-Gallate on Oxidative Stress and Matrix Metalloproteinases in Experimental Diabetes Mellitus

Background: The antioxidant properties of epigallocatechin-gallate (EGCG), a green tea compound, have been already studied in various diseases. Improving the bioavailability of EGCG by nanoformulation may contribute to a more effective treatment of diabetes mellitus (DM) metabolic consequences and vascular complications. The aim of this study was to test the comparative effect of liposomal EGCG with EGCG solution in experimental DM induced by streptozotocin (STZ) in rats. Method: 28 Wistar-Bratislava rats were randomly divided into four groups (7 animals/group): group 1—control group, with intraperitoneal (i.p.) administration of 1 mL saline solution (C); group 2—STZ administration by i.p. route (60 mg/100 g body weight, bw) (STZ); group 3—STZ administration as before + i.p. administration of EGCG solution (EGCG), 2.5 mg/100 g b.w. as pretreatment; group 4—STZ administration as before + i.p. administration of liposomal EGCG, 2.5 mg/100 g b.w. (L-EGCG). The comparative effects of EGCG and L-EGCG were studied on: (i) oxidative stress parameters such as malondialdehyde (MDA), indirect nitric oxide (NOx) synthesis, and total oxidative status (TOS); (ii) antioxidant status assessed by total antioxidant capacity of plasma (TAC), thiols, and catalase; (iii) matrix-metalloproteinase-2 (MMP-2) and -9 (MMP-9). Results: L-EGCG has a better efficiency regarding the improvement of oxidative stress parameters (highly statistically significant with p-values < 0.001 for MDA, NOx, and TOS) and for antioxidant capacity of plasma (highly significant p < 0.001 for thiols and significant for catalase and TAC with p < 0.05). MMP-2 and -9 were also significantly reduced in the L-EGCG-treated group compared with the EGCG group (p < 0.001). Conclusions: the liposomal nanoformulation of EGCG may serve as an adjuvant therapy in DM due to its unique modulatory effect on oxidative stress/antioxidant biomarkers and MMP-2 and -9.

Matrix Metalloproteinases in Diabetic Kidney Disease

Around the world diabetic kidney disease (DKD) is the main cause of chronic kidney disease (CKD), which is characterized by mesangial expansion, glomerulosclerosis, tubular atrophy, and interstitial fibrosis. The hallmark of the pathogenesis of DKD is an increased extracellular matrix (ECM) accumulation causing thickening of the glomerular and tubular basement membranes, mesangial expansion, sclerosis, and tubulointerstitial fibrosis. The matrix metalloproteases (MMPs) family are composed of zinc-dependent enzymes involved in the degradation and hydrolysis of ECM components. Several MMPs are expressed in the kidney; nephron compartments, vasculature and connective tissue. Given their important role in DKD, several studies have been performed in patients with DKD proposing that the measurement of their activity in serum or in urine may become in the future markers of early DKD. Studies from diabetic nephropathy experimental models suggest that a balance between MMPs levels and their inhibitors is needed to maintain renal homeostasis. This review focuses in the importance of the MMPs within the kidney and their modifications at the circulation, kidney and urine in patients with DKD. We also cover the most important studies performed in experimental models of diabetes in terms of MMPs levels, renal expression and its down-regulation effect.

Novel Biochemical Markers of Neurovascular Complications in Type 1 Diabetes Patients

Type 1 diabetes mellitus (T1DM) is associated with chronic complications, which are the result of neurovascular changes. There is still a lack of universal biochemical markers of microvascular damage. The present study aimed to investigate whether selected inflammatory proteins are related to the prevalence of microvascular complications in adult T1DM patients. The following markers were determined in a group of 100 T1DM participants: epidermal growth factor (EGF), metalloproteinase 2 (MMP-2), growth/differentiation factor 15 (GDF-15), and interleukin 29 (IL-29). Screening for microvascular complications, such as autonomic and peripheral neuropathy, diabetic kidney disease, and retinopathy, was conducted. The group was divided according to the occurrence of microvascular complications. At least one complication was required for the patient to be included in the microangiopathy group. The median EGF concentration in the microangiopathy group was higher than in the group without microangiopathy (p = 0.03). Increasing EGF concentration was a statistically significant predictor of the presence of microangiopathy in multivariate logistic regression analysis (p < 0.0001). Additionally, a higher GDF-15 level was associated with diabetic kidney disease, peripheral neuropathy, and proliferative retinopathy vs. nonproliferative retinopathy. GDF-15 concentration correlated negatively with estimated glomerular filtration rate (eGFR) (r = −0.28; p = 0.02). To conclude, higher EGF concentration is an independent predictor of the presence of microvascular complications in T1DM patients. Besides the relation between GDF-15 and diabetic kidney disease, it may be also associated with peripheral neuropathy and retinopathy.

MMP-10 is Increased in Early Stage Diabetic Kidney Disease and can be Reduced by Renin-Angiotensin System Blockade

Matrix metalloproteinases have been implicated in diabetic microvascular complications. However, little is known about the pathophysiological links between MMP-10 and the renin-angiotensin system (RAS) in diabetic kidney disease (DKD). We tested the hypothesis that MMP-10 may be up-regulated in early stage DKD, and could be down-regulated by angiotensin II receptor blockade (telmisartan). Serum MMP-10 and TIMP-1 levels were measured in 268 type 2 diabetic subjects and 111 controls. Furthermore, histological and molecular analyses were performed to evaluate the renal expression of Mmp10 and Timp1 in a murine model of early type 2 DKD (db/db) after telmisartan treatment. MMP-10 (473 ± 274 pg/ml vs. 332 ± 151; p = 0.02) and TIMP-1 (573 ± 296 ng/ml vs. 375 ± 317; p < 0.001) levels were significantly increased in diabetic patients as compared to controls. An early increase in MMP-10 and TIMP-1 was observed and a further progressive elevation was found as DKD progressed to end-stage renal disease. Diabetic mice had 4-fold greater glomerular Mmp10 expression and significant albuminuria compared to wild-type, which was prevented by telmisartan. MMP-10 and TIMP-1 are increased from the early stages of type 2 diabetes. Prevention of MMP-10 upregulation observed in diabetic mice could be another protective mechanism of RAS blockade in DKD.

Cheiroarthropathy and tendinopathy in diabetes

Joint problems commonly occur in people with diabetes. Cheiroarthropathy affects the hands and results in painless limited finger joint extension, appearing to be associated with longer diabetes duration and the presence of microvascular complications. The prevalence of cheiroarthropathy seems to be falling, perhaps as a result of improvements in glycaemic management. Non-enzymatic glycation of collagen results in abnormally crosslinked protein resistant to degradation with subsequent increased build-up of collagen in joints. The management of cheiroarthropathy is predominantly conservative, with occupational and hand therapy at the forefront. Tendinopathy is more common in people with diabetes than those without, and is associated with obesity and insulin resistance. As with cheiroarthropathy, the exact causative mechanism of tendinopathy in diabetes is not known, but may be linked to inflammation, apoptosis and increased vascularity of affected tendons, driven by hyperinsulinaemia. Local fat pads have also been suggested to play a role in the pathogenesis of tendinopathy.

Matrix Metalloproteinases in Renal Diseases: A Critical Appraisal

Matrix metalloproteinases (MMPs) are endopeptidases within the metzincin protein family that not only cleave extracellular matrix (ECM) components, but also process the non-ECM molecules, including various growth factors and their binding proteins. MMPs participate in cell to ECM interactions, and MMPs are known to be involved in cell proliferation mechanisms and most probably apoptosis. These proteinases are grouped into six classes: collagenases, gelatinases, stromelysins, matrilysins, membrane type MMPs, and other MMPs. Various mechanisms regulate the activity of MMPs, inhibition by tissue inhibitors of metalloproteinases being the most important. In the kidney, intrinsic glomerular cells and tubular epithelial cells synthesize several MMPs. The measurement of circulating MMPs can provide valuable information in patients with kidney diseases. They play an important role in many renal diseases, both acute and chronic. This review attempts to summarize the current knowledge of MMPs in the kidney and discusses recent data from patient and animal studies with reference to specific diseases. A better understanding of the MMPs' role in renal remodeling may open the way to new interventions favoring deleterious renal changes in a number of kidney diseases.

Urine Levels of Matrix Metalloproteinases and Tissue Inhibitor of Metalloproteinases in Children with Type 1 Diabetes Mellitus

Objective

Histopathological changes in the kidney in type 1 diabetes mellitus (T1DM) begin before detection of microalbuminuria. Therefore, there is interest in finding a better biomarker for the early detection of diabetic kidney injury. The aim of this present study was to determine whether urinary indicators of fibrosis are detectable early in the development of T1DM in children and if they may predict progressive renal injury.

Methods

Urinary matrix metalloproteinase 2 and 9 (MMP2 and MMP9), tissue inhibitor of metalloproteinase 1 and 2 (TIMP1 and TIMP2) and transforming growth factor-β1 (TGF-β1) were assessed in 33 patients with T1DM with normal renal functions and in 24 healthy controls. Microalbuminuria was not present in the patient group with the exception of three patients. The results were adjusted to urine creatinine (Cr) and the differences between patients and controls were evaluated. These measurements were repeated after one year and the results were compared with the first year results.

Results

Urine MMP2/Cr, MMP9/Cr, TIMP1/Cr, TIMP2/Cr, TGF-β1/Cr were not different between the patient and control groups (p>0.05). There were also no significant differences between the first and second year results for these biomarkers (p>0.05). None of these parameters were correlated with hemoglobin A1c, body mass index and duration of T1DM. Interestingly, all parameters were negatively correlated to age of onset of T1DM (p<0.05).

Conclusion

Our findings suggest that urinary biomarkers of fibrosis do not show an increase in diabetic children without microalbuminuria. The results also indicate that the risk of early fibrosis may increase as age of onset of T1DM decreases.

MMP targeting in the battle for vision: Recent developments and future prospects in the treatment of diabetic retinopathy

Matrix metalloproteinases (MMPs) are enzymes capable of degrading nearly all types of extracellular matrix. They perform a wide range of roles in physiological processes, which is the reason for their strict regulation by numerous mechanisms including natural tissue inhibitors of metalloproteinases (TIMP). Research only started to shed light on more troublesome aspects of MMPs function, like cancer progression, Alzheimer's disease, atherosclerosis, ageing. Moreover, their profound role in diabetes is being carefully investigated including one of its most debilitating complications - diabetic retinopathy (DR), the leading cause of acquired blindness worldwide. Traditional treatment of this condition seems to be only mildly satisfactory, which elicited substantial interest in the field of new therapeutic methods including MMP targeting. So far, significant roles of MMP-2 and MMP-9 in the development of retinopathy have been established, with special attention given to the process of blood-retinal barrier impairment. Further exploration revealed MMP-10 and MMP-14 involvement as well as changes in MMP/TIMP ratio. In this review, we provide insight into MMPs role in diabetic retinopathy with a clarification of various mechanisms regulating MMP activity in the light of the recent studies. We conclude with an overview of novel DR therapies targeting MMPs and point to the need of further examination of their usefulness in clinical setting, with an eye towards future research.

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in chronic kidney disease and acute kidney injury: a systematic review of the literature

INTRODUCTION

Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteinases involved in remodeling the extracellular matrix. Tissue inhibitors of metalloproteinases (TIMPs) are a family of four proteins that act to limit the degradative actions of MMPs. Chronic kidney disease (CKD) and acute kidney injury (AKI) are public health problems worldwide, the prevalence of which has been increasing. Recent concept considers MMPs and TIMPs as critical factors before the onset of microalbuminuria, as well as accelerating factors associated with the breakdown of the glomerular basement membrane, renal scarring, and fibrosis during the progression of kidney diseases. Here we reviewed studies of the expression of MMPs and TIMPs in humans, using as clinical samples serum, plasma, and urine, with a focus on their potential role as molecular markers in CKD and AKI, as non-invasive markers.

MATERIAL AND METHODS

We used as data sources, studies at Medline database using combinations of the following keywords: CKD, AKI, MMP, TIMP, serum, plasma, and urine.

RESULTS

Evidence suggests that MMPs/TIMPs could be potential targets for therapeutic intervention in kidney diseases; future studies should attempt to improve the diagnostic or prognostic power of these families.

DISCUSSION

Considering published guides, such as biospecimen reporting for improved study quality (BRISQ), strengthening the reporting of observational studies in epidemiology (STROBE), an updated list of essential items for reporting diagnostic accuracy studies (STARD), transparent reporting of a multivariate prediction model for individual prognosis or diagnosis (TRIPOD), and on the studies reviewed here, we have adapted published recommendations and proposed other news in order to enhance the transparency and quality of MMPs/TIMPs research in CKD and AKI. This review reinforces the complexities of MMPs/TIMPs in the pathobiology of the kidney and the need for well-designed and transparent biomedical studies. HIPPOKRATIA 2018, 22(3): 99-104.

Anti-apoptotic activity of human matrix metalloproteinase-2 attenuates diabetes mellitus

BACKGROUND

Chronic progression of diabetes is associated with decreased pancreatic islet mass due to apoptosis of β-cells. Patients with diabetes have increased circulating matrix metalloproteinase-2 (MMP2); however, the physiological significance has remained elusive. This study tested the hypothesis that MMP2 inhibits cell apoptosis, including islet β-cells.

METHODS

Samples from diabetic patients and newly developed transgenic mice overexpressing human MMP2 (hMMP2) were harnessed, and diabetes was induced with streptozotocin.

RESULTS

Circulating hMMP2 was significantly increased in diabetic patients compared to controls and significantly correlated with the serum C-peptide levels. The diabetic hMMP2 transgenic mice showed significant improvements in glycemia, glucose tolerance and insulin secretion compared to diabetic wild type mice. Importantly, the increased hMMP2 levels in mice correlated with significant reduction in islet β-cell apoptosis compared to wild-type counterparts, and an inhibitor of hMMP2 reversed this mitigating activity against diabetes. The increased activation of Akt and BAD induced by hMMP2 in β-cells compared to controls, links this signaling pathway to the anti-apoptotic activity of hMMP2, a property that was reversible by both an hMMP2 inhibitor and antibody against integrin-β3.

CONCLUSION

Overall, this study demonstrates that increased expression of hMMP2 may attenuate the severity of diabetes by protecting islet β-cells from apoptosis through an integrin-mediated activation of the Akt/BAD pathway.

Urinary metalloproteinases and tissue inhibitors of metalloproteinases as potential early biomarkers for renal fibrosis in children with nephrotic syndrome

In chronic glomerulopathies, renal fibrosis (RF) results from extracellular matrix remodeling processes regulated by matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP). We assessed urinary (u-) and serum (s-) MMP-1, -2, -9, TIMP-1, -2 concentrations and MMP-1, -2, -9/TIMP-1, -2 ratios in children with nephrotic syndrome. Steroid-dependent and steroid-resistant nephrotic patients (SDNS-Ps and SRNS-Ps, respectively) were compared with respect to measured parameters. The correlations of measured parameters with magnitude of proteinuria and histopathological diagnosis were determined.The study comprised of 39 children with nephrotic syndrome and 20 healthy controls. Twenty-three patients had SDNS and 16 ones-SRNS. The concentrations MMPs and TIMPs were measured using enzyme-linked immunosorbent assay.In nephrotic patients, higher u-MMP-1, -2, -9/creatinine ratios and u-TIMP-1, -2/creatinine ratios were observed as compared with controls. Nephrotic children were also characterized by lower MMP-1, -2, -9/TIMP-1 ratios. In SRNS-Ps, u-MMP-2/creatinine ratio and u-TIMP-1/creatinine ratio were higher as compared with SDNS-Ps. Magnitude of proteinuria correlated positively with u-MMP-2/creatinine ratio and negatively with u-MMP-2/TIMP-1. In minimal change disease (MCD) patients as compared with those with other glomerulopathies, there was higher u-MMP-2/TIMP-1 ratio. No significant differences in s-MMPs, s-TIMPs, and s-MMPs/TIMPs ratios between nephrotic patients and controls were observed.Children with nephrotic syndrome are characterized by increased u-fibrotic biomarkers excretions. U-MMP-1, -2, -9 excretions and u-MMP-2/TIMP-1 ratio may become potential early biomarkers for RF. SRNS-Ps, those with heavier proteinuria and other than MCD glomerulopathies, seem to be more susceptible to early RF.

Proteins of TNF-α and IL6 Pathways Are Elevated in Serum of Type-1 Diabetes Patients with Microalbuminuria

Soluble cytokine receptors may play an important role in development of microalbuminuria (MA) in type-1 diabetes (T1D). In this study, we measured 12 soluble receptors and ligands from TNF-α/IL6/IL2 pathways in T1D patients with MA (n = 89) and T1D patients without MA (n = 483) participating in the PAGODA study. Twelve proteins in the sera from T1D patients with and without MA were measured using multiplex Luminex assays. Ten serum proteins (sTNFR1, sTNFR2, sIL2Rα, MMP2, sgp130, sVCAM1, sIL6R, SAA, CRP, and sICAM1) were significantly elevated in T1D patients with MA. After adjusting for age, duration of diabetes, and sex in logistic regression, association remained significant for seven proteins. MA is associated with increasing concentrations of all 10 proteins, with the strongest associations observed for sTNFR1 (OR = 108.3, P < 10⁻³²) and sTNFR2 (OR = 65.5, P < 10⁻³⁷), followed by sIL2Rα (OR = 12.9, P < 10⁻¹³), MMP2 (OR = 5.5, P < 10⁻⁶), sgp130 (OR = 5.2, P < 10⁻³), sIL6R (OR = 4.6, P < 10⁻⁴), and sVCAM1 (OR = 3.3, P < 10⁻⁴). We developed a risk score system based on the combined odds ratios associated with each quintile for each protein. The risk scores cluster MA patients into three subsets, each associated with distinct risk for MA attributable to proteins in the TNF-α/IL6 pathway (mean OR = 1, 13.5, and 126.3 for the three subsets, respectively). Our results suggest that the TNF-α/IL6 pathway is overactive in approximately 40% of the MA patients and moderately elevated in the middle 40% of the MA patients. Our results suggest the existence of distinct subsets of MA patients identifiable by their serum protein profiles.

Matrix metalloproteinase 14 modulates diabetes and Alzheimer's disease cross-talk: a meta-analysis

Diabetes mellitus is associated with dementia, but whether diabetes is associated with Alzheimer's disease remains controversial. Alzheimer's disease is characterized by amyloid beta aggregation. We hypothesized that genes, involved in amyloid beta degradation, may be altered due to diabetes and thus participate in progression of Alzheimer's disease. Expression profiling of amyloid beta-degrading enzymes in streptozotocin-induced diabetic mice and their correlation with expression of amyloid precursor protein in hippocampus of Alzheimer's disease patients were accessed. We found that matrix metalloproteinase 14 decreased in brain but not in other tissues of streptozotocin-induced diabetic mice, and was negatively correlated with expression of amyloid precursor protein in hippocampus of Alzheimer's disease patients. These findings suggested matrix metalloproteinase 14 may link insulin-deficient diabetes to Alzheimer's disease.

Association of Urinary Activity of MMP-2 with Microalbuminuria in an Isolated Sample of Subjects Living in High Altitude Rural Locations in México

Hernández-Hernández, Magda Elena, Jaime Morales-Romero, Clara Luz Sampieri, Diego Jesús Luna Lozano, Isidra del Carmen Valencia Lezama, Mónica Janett Muñoz Contreras, and Arturo Rodríguez Hernández. Association of urinary activity of MMP-2 with microalbuminuria in an isolated sample of subjects living in high altitude rural locations in México. High Alt Med Biol. 18:209-218, 2017.-Matrix metalloproteinases (MMP) are implicated in remodeling of the renal extracellular matrix. In a cross-sectional study we evaluated renal impairment in general population of high-altitude rural locations in México. Multivariable analysis was performed to identify the association between MMP-2 and MMP-9 and microalbuminuria. Twenty-eight (20.9%) subjects with renal impairment (WRI) and 106 (79.1%) without renal impairment were included. No differences were found relating to sex, location, marital status, current habits, weight, height, body mass index, waist size in males, creatinine in males, and uric acid. In contrast, differences were found among age, level of education, waist size in general and in females, creatinine in general and in females, urinary albumin, urea, glucose, total cholesterol, and triglycerides. Proportions of hypertension, type 2 diabetes mellitus, central abdominal obesity, hypertriglyceridemia, and hypercholesterolemia were greater in the group WRI. Presence of urinary MMP-2 or of both urinary gelatinases and arbitrary unit (AU) values ≥P₉₀ were associated with microalbuminuria. We conclude that AU values ≥P₉₀ of urinary MMP-2 (OR = 20.1, p = 0.002) is associated with microalbuminuria.

Plasma matrix metalloproteinases are associated with incident cardiovascular disease and all-cause mortality in patients with type 1 diabetes: a 12-year follow-up study

Background

Altered regulation of extracellular matrix remodeling by matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase (TIMP) may contribute to vascular complications in type 1 diabetes. We investigated associations between plasma MMP-1, -2, -3, -9, -10 and TIMP-1, and cardiovascular events and all-cause mortality in type 1 diabetic patients.

Methods

We prospectively followed 337 type 1 diabetic patients [mean age 41.4 years (9.6), 39% female], 170 with and 167 without diabetic nephropathy, with median follow-up of 12.3 years. Survival analyses were applied to investigate differences in plasma MMP-1, -2, -3, -9, -10, and TIMP-1-levels in patients with and without a cardiovascular event and in those who died vs survivors. All analyses were adjusted for age, sex, duration of diabetes, HbA1c, nephropathy and for other conventional cardiovascular risk factors.

Results

After adjustment for potential confounders, higher MMP-2 plasma levels were significantly associated with higher incidence of cardiovascular events [HR 1.49 (95% CI 1.11; 1.99)], and higher plasma levels of MMP-1 [1.38 (1.07; 1.78)], MMP-2 [1.60 (1.19; 2.15)] and MMP-3 [1.39 (1.05; 1.85)] were associated with all-cause mortality. All associations were independent of low-grade inflammation and endothelial dysfunction as estimated by plasma markers. Associations between MMP-2 and cardiovascular events and between MMP-3 and mortality were attenuated after further adjustment for eGFR and changes in eGFR.

Conclusions

Higher levels of MMP-2 are associated with CVD and higher MMP-1, -2 and -3 with all-cause mortality. In addition, associations between MMP-2 and CVD, and MMP-3 and mortality were attenuated after adjustment for eGFR while both MMPs were associated with eGFR decline, indicating a possible mediating role of eGFR.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-017-0539-1) contains supplementary material, which is available to authorized users.

Systems Biology-Derived Biomarkers to Predict Progression of Renal Function Decline in Type 2 Diabetes

OBJECTIVE

Chronic kidney disease (CKD) in diabetes has a complex molecular and likely multifaceted pathophysiology. We aimed to validate a panel of biomarkers identified using a systems biology approach to predict the individual decline of estimated glomerular filtration rate (eGFR) in a large group of patients with type 2 diabetes and CKD at various stages.

RESEARCH DESIGN AND METHODS

We used publicly available "omics" data to develop a molecular process model of CKD in diabetes and identified a representative parsimonious set of nine molecular biomarkers: chitinase 3-like protein 1, growth hormone 1, hepatocyte growth factor, matrix metalloproteinase (MMP) 2, MMP7, MMP8, MMP13, tyrosine kinase, and tumor necrosis factor receptor-1. These biomarkers were measured in baseline serum samples from 1,765 patients recruited into two large clinical trials. eGFR decline was predicted based on molecular markers, clinical risk factors (including baseline eGFR and albuminuria), and both combined, and these predictions were evaluated using mixed linear regression models for longitudinal data.

RESULTS

The variability of annual eGFR loss explained by the biomarkers, indicated by the adjusted R² value, was 15% and 34% for patients with eGFR ≥60 and <60 mL/min/1.73 m², respectively; variability explained by clinical predictors was 20% and 31%, respectively. A combination of molecular and clinical predictors increased the adjusted R² to 35% and 64%, respectively. Calibration analysis of marker models showed significant (all P < 0.0001) but largely irrelevant deviations from optimal calibration (calibration-in-the-large: -1.125 and 0.95; calibration slopes: 1.07 and 1.13 in the two groups, respectively).

CONCLUSIONS

A small set of serum protein biomarkers identified using a systems biology approach, combined with clinical variables, enhances the prediction of renal function loss over a wide range of baseline eGFR values in patients with type 2 diabetes and CKD.

The restorative role of annexin A1 at the blood-brain barrier

Annexin A1 is a potent anti-inflammatory molecule that has been extensively studied in the peripheral immune system, but has not as yet been exploited as a therapeutic target/agent. In the last decade, we have undertaken the study of this molecule in the central nervous system (CNS), focusing particularly on the primary interface between the peripheral body and CNS: the blood-brain barrier. In this review, we provide an overview of the role of this molecule in the brain, with a particular emphasis on its functions in the endothelium of the blood-brain barrier, and the protective actions the molecule may exert in neuroinflammatory, neurovascular and metabolic disease. We focus on the possible new therapeutic avenues opened up by an increased understanding of the role of annexin A1 in the CNS vasculature, and its potential for repairing blood-brain barrier damage in disease and aging.

Rethinking glomerular basement membrane thickening in diabetic nephropathy: adaptive or pathogenic?

Diabetic nephropathy (DN) is the leading cause of chronic kidney disease in the United States and is a major cause of cardiovascular disease and death. DN develops insidiously over a span of years before clinical manifestations, including microalbuminuria and declining glomerular filtration rate (GFR), are evident. During the clinically silent period, structural lesions develop, including glomerular basement membrane (GBM) thickening, mesangial expansion, and glomerulosclerosis. Once microalbuminuria is clinically apparent, structural lesions are often considerably advanced, and GFR decline may then proceed rapidly toward end-stage kidney disease. Given the current lack of sensitive biomarkers for detecting early DN, a shift in focus toward examining the cellular and molecular basis for the earliest structural change in DN, i.e., GBM thickening, may be warranted. Observed within one to two years following the onset of diabetes, GBM thickening precedes clinically evident albuminuria. In the mature glomerulus, the podocyte is likely key in modifying the GBM, synthesizing and assembling matrix components, both in physiological and pathological states. Podocytes also secrete matrix metalloproteinases, crucial mediators in extracellular matrix turnover. Studies have shown that the critical podocyte-GBM interface is disrupted in the diabetic milieu. Just as healthy podocytes are essential for maintaining the normal GBM structure and function, injured podocytes likely have a fundamental role in upsetting the balance between the GBM's synthetic and degradative pathways. This article will explore the biological significance of GBM thickening in DN by reviewing what is known about the GBM's formation, its maintenance during health, and its disruption in DN.

Matrix Metalloproteinase-1 and Matrix Metalloproteinase-9 in the Aqueous Humor of Diabetic Macular Edema Patients

Purpose

To assess the concentrations of matrix metalloproteinase (MMP)-1 and MMP-9 in the aqueous humor of diabetic macular edema (DME) patients.

Method

The concentrations of MMP-1 and MMP-9 in the aqueous humors of 15 cataract patients and 25 DME patients were compared. DME patients were analyzed according to the diabetic retinopathy (DR) stage, diabetes mellitus (DM) duration, pan-retinal photocoagulation (PRP) treatment, recurrence within 3 months, HbA1C (glycated hemoglobin) level, and axial length.

Results

The concentrations of MMP-1 and MMP-9 of the DME groups were higher than those of the control group (p = 0.005 and p = 0.002, respectively). There was a significant difference in MMP-1 concentration between the mild non-proliferative diabetic retinopathy (NPDR) group and the proliferative diabetic retinopathy (PDR) group (p = 0.012). MMP-1 concentrations were elevated in PRP-treated patients (p = 0.005). There was a significant difference in MMP-9 concentrations between the mild NPDR group and the PDR group (p < 0.001), and between the moderate and severe NPDR group and the PDR group (p < 0.001). The MMP-9 concentrations in PRP treated patients, DM patients with diabetes ≥ 10 years and recurrent DME within 3months were elevated (p = 0.023, p = 0.011, and p = 0.027, respectively). In correlation analyses, the MMP-1 level showed a significant correlation with age (r = -0.48, p = 0.01,), and the MMP-9 level showed significant correlations with axial length (r = -0.59, p < 0.01) and DM duration (r = 049, p = 0.01).

Conclusions

Concentrations of MMP-1 and MMP-9 were higher in the DME groups than in the control group. MMP-9 concentrations also differed depending on DR staging, DM duration, PRP treatment, and degree of axial myopia. MMP-9 may be more important than MMP-1 in the induction of DM complications in eyes.

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.

The serum protein fetuin-B is involved in the development of acute myocardial infarction

Fetuin-B was one of highly expressed serum proteins in AMI compared with stable angina. This protein affected vascular plaque-stabilizing components in monocytes, macrophages and vascular smooth muscle cells. Fetuin-B may be a possible contributor to AMI.

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.

Biofluid proteases profiling in diabetes mellitus

The investigation of protease relevance in biologic systems beyond catabolism of proteins and peptides to amino acids has stimulated interest as to their role in the pathogenesis of several disorders including diabetes mellitus (DM). Evaluation of proteases and the assessment of their activity in biofluids are fundamental to elucidate these proteolytic systems in DM and its related complications. In contrast to traditional immunoassay or substrate based approaches that targeted specific proteases and their inhibitors, the field of degradomics has provided a comprehensive approach to study these enzymes. Although the degradome contains over 500 proteases, very few have been associated with DM and its micro- and macrovascular complications. In this paper, we review these proteases and their respective inhibitors with emphasis on DM. It is likely that future research will expand these initial studies and look to develop high throughput automated technologies to identify and characterize biofluid proteases of diagnostic and prognostic value in other pathologies.

Advanced glycation end products induce glomerular endothelial cell hyperpermeability by upregulating matrix metalloproteinase activity

The present study aimed to investigate the effects of advanced glycation end‑products (AGEs) on the permeability of glomerular endothelial cells (GEnCs) and determine whether enhanced permeability was due to degradation of tight junction (TJ) complexes by matrix metalloproteinases (MMPs). Cultured monolayers of GEnCs were exposed to AGEs at different doses and treatment durations in the presence or absence of the organic MMP‑2/9 inhibitor (2R)‑2‑((4‑biphenyl sulfony‑l)amino)‑3‑phenylproprionic acid) (BiPs). Expression of the TJ proteins occludin and claudin‑5 was determined by western blot analysis and immunofluorescence, while the permeability of the GEnCs was measured using transendothelial electrical resistance and by diffusion of 4 kDa fluorescein isothiocyanate (FITC)‑dextran. The activities of MMP‑2 and MMP‑9 were assayed using gelatin zymography. The results indicated that AGE‑treated cultures significantly reduced occludin and claudin‑5 immunoreactivity. Similarly, the surface expression of these proteins was significantly reduced and rows of TJs which normally connect endothelial cells became discontinuous or fractured following AGE exposure. Disruption of TJs was accompanied by significantly reduced transendothelial resistance and hyperpermeability to FITC‑dextran. Treatment with AGEs evoked a dose‑ and time‑dependent upregulation of MMP‑2 and MMP‑9. However, co‑administration of AGEs and BiPS, an inhibitor of MMP‑2/MMP‑9, inhibited the downregulation of occludin and claudin‑5, with a concomitant reversal of GEnC monolayer hyperpermeability. In conclusion, AGEs promoted glomerular hyperpermeability in vitro by the MMP‑mediated disruption of TJs. Chronic elevation of endothelial cell AGEs in diabetes mellitus may contribute to glomerular hyperpermeability by inducing the overexpression of MMPs, which degrade TJs, leading to proteinuria.

Effect of a Novel, Orally Active Matrix Metalloproteinase-2 and -9 Inhibitor in Spinal and Trigeminal Rat Models of Neuropathic Pain

AIMS

To study the effects of a novel matrix metalloproteinase-2 (MMP-2) and MMP-9 inhibitor, AQU-118, on mechanical allodynia in the spinal nerve ligation (SNL) model of neuropathic pain and the chronic constriction injury of the infraorbital nerve (CCI-IoN) model of neuropathic orofacial pain.

METHODS

Five groups of SNL rats were given daily oral doses of AQU-118 (5, 10, 20 mg/kg), gabapentin (100 mg/kg), or vehicle (0.5% methylcellulose) and then paw withdrawal threshold was measured with von Frey filaments (VF). Three groups of CCI-IoN rats were given daily oral doses of either AQU-118 (40 mg/kg), gabapentin (100 mg/kg), or vehicle (0.5% methylcellulose) and then mechanical allodynia was measured with facial VF and non-reflex-based orofacial stimulation test (OFST) assay. Naïve rats were also tested for the effect of AQU-118 (40 mg/kg) on basal sensitivity to mechanical stimulation/locomotive activity.

RESULTS

Mechanical allodynia in SNL rats was attenuated by gabapentin (100 mg/kg) and AQU-118 (in a dose-dependent manner). Mechanical allodynia in CCI-IoN rats was also attenuated (in an equipotent manner) by both AQU-118 (40 mg/ kg) and gabapentin (100 mg/kg) as measured by both facial VF and OFST assay. Upon cessation of either AQU-118 or gabapentin, VF-related responses in both models and OFST assay times reverted to levels observed in vehicle-treated rats. No statistically significant change was observed in locomotive activity/paw withdrawal threshold by AQU-118 (40 mg/kg) in naïve rats.

CONCLUSION

The results demonstrated that oral AQU-118 attenuates mechanical allodynia in both neuropathic pain models and with efficacies that mirror gabapentin at the 40 mg/kg dose used in the CCI-IoN model but without effect on basal sensitivity to mechanical stimulation/locomotive activity. These findings support a possible role for MMP-2/-9 in the etiology of neuropathic pain and also suggest that inhibition strategies represent a viable treatment option.

Renal dysfunction and intragraft proMMP9 activity in renal transplant recipients with interstitial fibrosis and tubular atrophy

Chronic renal allograft injury is reflected by interstitial fibrosis and tubular atrophy (IF/TA) and by the accumulation of extracellular matrix (ECM). Metalloproteinases (MMPs) are renal physiologic regulators of ECM degradation. Changes in MMPs expression or activity may disturb ECM turnover leading to glomerular scarring and worsening renal function. Our goal was to investigate intragraft MMP2 and MMP9 activities and their correlation with renal dysfunction. Plasma MMP2 and MMP9 activities were analyzed as noninvasive markers of renal allograft deterioration. Transplanted patients were biopsied and histopathologically characterized as IF/TA+ or IF/TA-. Renal function was evaluated by serum creatinine, glomerular filtration rate (GFR) estimated by Modification of Diet in Renal Disease equation and urinary protein/creatinine ratio. Kidney and plasma MMP2 and MMP9 activities were analyzed by zymography. A significant renal dysfunction was observed in IF/TA+ patients. Intragraft proMMP9 showed a significant higher activity in IF/TA+ than in IF/TA- samples and was inversely correlated with the GFR. Intragraft proMMP2 activity tended to increase in IF/TA+ samples, although no statistic significance was reached. Circulating proMMP2 and proMMP9 activities did not show significant differences between groups. Our data provide evidence that correlates intragraft proMMP9 activity with the fibrotic changes and renal dysfunction observed in IF/TA.

Effects of reduced β2-glycoprotein I on the expression of aortic matrix metalloproteinases and tissue inhibitor matrix metalloproteinases in diabetic mice

Background

Reduced β₂-glycoprotein I (reduced β₂GP I), which has free sulfhydryl groups, is present in plasma and serum; it can protect vascular endothelial cells from damage due to oxidative stress in vitro. We investigated the effects of reduced β₂GP I on the expression of various matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in the aortas of diabetic mice.

Methods

We provided 120 female 8-week-old Balb/c mice with a high sugar, high fat diet. After 8 weeks they were injected with streptozotocin to induce diabetes. We treated mice in the mono dose groups with β₂GP I, reduced β₂GP I, or phosphate-buffered saline (PBS) on day 1 and fed them for 3 weeks. The mice in the complex dose groups were treated with β₂GP I, reduced β₂GP I, or PBS on days 1 and 22 and fed for 6 weeks. Control mice were given a standard chow diet. Blood lipids were measured at the end of 3 or 6 weeks, and aortas removed to observe morphological and molecular biological changes.

Results

The low-density lipoprotein cholesterol levels in mice of the reduced β₂GP I group were lower than those in the diabetic group. Aortic lipid deposition in the reduced β₂GP I group was significantly less than in the diabetic control group. In the aortas, reduced β₂GP I decreased MMP2/TIMP2 mRNA and protein expression levels, and MMP9/TIMP1 expression levels compared with those in diabetic controls. Reduced β₂GP I down-regulated p38 mitogen-activated protein kinase (p38MAPK) mRNA expression and phosphorylated p38MAPK protein expression compared with those in diabetic controls of the complex dose group.

Conclusions

Reduced β₂GP I plays a role in diabetic mice related to vascular protection, inhibiting vascular lipid deposition, and plaque formation by reducing MMPs/TIMPs expression through down-regulation of the p38MAPK signaling pathway.