Metalloproteinase Changes in Diabetes

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.

Chemical tools to monitor bladder cancer progression

BackgroundBladder cancer (BCa) is the most common cancer of the urinary system. Due to its high incidence and recurrence, as well as limited progress in the effective treatment, BCa is a challenge for today's medicine.Materials and MethodsWe used a set of chromogenic substrates to differentiate between the stages of bladder cancer progression (G1 (n = 10), G2 (n = 10), G3 (n = 10)). The proteolytic activity in individual the urine samples was determined by absorbance measurements. Then inhibitors of particular classes of enzymes were used to determine which enzymes dominate at a given stage of the neoplastic disease.ResultsThe specific activity of enzymes in the urine of patients with confirmed bladder cancer was determined separately for three (G1, G2, G3) stages of the disease development. What is more, no activity was observed in urine of healthy people (n = 10).DiscussionResearch shows that specific enzymes are associated with the development of specific stages of cancer. We suspect that the differences in the proteolytic activity of urine samples are due to the presence of a different set of enzymes, that are directly related to the particular stage of the disease.ConclusionWe obtained three substrates for monitoring individual stages of bladder cancer development.

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.

DYNAMIC BIOREACTOR MODEL TO MIMIC EARLY CARDIAC FIBROSIS IN DIABETES

In clinical diabetic cardiomyopathy, hyperglycemia and dyslipidemia induce tissue injury, activation of cardiac fibroblasts and interstitial and perivascular fibrosis. Myofibroblasts repair the injured tissue by increasing collagen deposition in the cardiac interstitium and suppressing the activity of matrix metalloproteinases. The goal of this study was to find an ideal model to mimic the effect of high glucose concentration on human cardiac fibroblast activation. The profibrotic role of the transforming growth factor-[Formula: see text] (TGF-[Formula: see text]) and the protective modulation of nitric oxide were examined in two-dimensional and three-dimensional cell culture models, as well as tissue engineering models, that involved the use of cardiac fibroblasts cultured within myocardial matrix scaffolds mounted in a bioreactor that delivered biochemical and mechanical stimuli. Results showed that high glucose levels were potent pro-fibrotic stimuli. In addition, high glucose levels in concert with TGF-[Formula: see text] constituted very strong signals that induced human cardiac fibroblast activation. Cardiac fibroblasts cultured within decellularized myocardial scaffolds and exposed to biochemical and mechanical stimuli represented an adequate model for this pathology. In conclusion, the bioreactor platform was instrumental in establishing an in vitro model of early fibrosis; this platform could be used to test the effects of various agents targeted to mitigate the fibrotic processes.

Diabetes-related intestinal region-specific thickening of ganglionic basement membrane and regionally decreased matrix metalloproteinase 9 expression in myenteric ganglia

BACKGROUND

The importance of the neuronal microenvironment has been recently highlighted in gut region-specific diabetic enteric neuropathy. Regionally distinct thickening of endothelial basement membrane (BM) of intestinal capillaries supplying the myenteric ganglia coincide with neuronal damage in different intestinal segments. Accelerated synthesis of matrix molecules and reduced degradation of matrix components may also contribute to the imbalance of extracellular matrix dynamics resulting in BM thickening. Among the matrix degrading proteinases, matrix metalloproteinase 9 (MMP9) and its tissue inhibitor (TIMP1) are essential in regulating extracellular matrix remodelling.

AIM

To evaluate the intestinal segment-specific effects of diabetes and insulin replacement on ganglionic BM thickness, MMP9 and TIMP1 expression.

METHODS

Ten weeks after the onset of hyperglycaemia gut segments were taken from the duodenum and ileum of streptozotocin-induced diabetic, insulin-treated diabetic and sex- and age-matched control rats. The thickness of BM surrounding myenteric ganglia was measured by electron microscopic morphometry. Whole-mount preparations of myenteric plexus were prepared from the different gut regions for MMP9/TIMP1 double-labelling fluorescent immunohistochemistry. Post-embedding immunogold electron microscopy was applied on ultrathin sections to evaluate the MMP9 and TIMP1 expression in myenteric ganglia and their microenvironment from different gut segments and conditions. The MMP9 and TIMP1 messenger ribonucleic acid (mRNA) level was measured by quantitative polymerase chain reaction.

RESULTS

Ten weeks after the onset of hyperglycaemia, the ganglionic BM was significantly thickened in the diabetic ileum, while it remained intact in the duodenum. The immediate insulin treatment prevented the diabetes-related thickening of the BM surrounding the ileal myenteric ganglia. Quantification of particle density showed an increasing tendency for MMP9 and a decreasing tendency for TIMP1 from the proximal to the distal small intestine under control conditions. In the diabetic ileum, the number of MMP9-indicating gold particles decreased in myenteric ganglia, endothelial cells of capillaries and intestinal smooth muscle cells, however, it remained unchanged in all duodenal compartments. The MMP9/TIMP1 ratio was also decreased in ileal ganglia only. However, a marked segment-specific induction was revealed in MMP9 and TIMP1 at the mRNA levels.

CONCLUSION

These findings support that the regional decrease in MMP9 expression in myenteric ganglia and their microenvironment may contribute to extracellular matrix accumulation, resulting in a region-specific thickening of ganglionic BM.

Responses of matrix metalloproteinases to hyperbaric oxygen treatment: changing for good or ill?

Background: Hyperbaric oxygen (HBO₂) is currently emerging as a promising therapeutic option for diseases involving impaired tissue repair and remodeling. In this regard, HBO₂ has been shown to modulate signaling pathways responsible for matrix metalloproteinases (MMPs) regulation, which makes the MMPs interesting targets for investigation. However, the understanding regarding how HBO₂ treatment affects the expression and activity of the MMP family members in different tissues and diseases needs to be clarified. The precise roles of MMPs in the physiopathology of various tissue repair disorders also remain unclear. Because of potential off-target systemic effects of the HBO₂ on MMPs, researchers and physicians should carefully consider whether their patients could be affected adversely by HBO₂ exposure. Aims: This narrative review provides an overview of MMP biology (structure, function, and regulation) and summarizes available data showing how MMPs respond to HBO₂ in different tissues and pathologies, also highlighting possible mechanisms.

The Roles of Matrix Metalloproteinases and Their Inhibitors in Human Diseases

Matrix metalloproteinases (MMPs) are a family of zinc-dependent extracellular matrix (ECM) remodeling endopeptidases that have the capacity to degrade almost every component of the ECM. The degradation of the ECM is of great importance, since it is related to embryonic development and angiogenesis. It is also involved in cell repair and the remodeling of tissues. When the expression of MMPs is altered, it can generate the abnormal degradation of the ECM. This is the initial cause of the development of chronic degenerative diseases and vascular complications generated by diabetes. In addition, this process has an association with neurodegeneration and cancer progression. Within the ECM, the tissue inhibitors of MMPs (TIMPs) inhibit the proteolytic activity of MMPs. TIMPs are important regulators of ECM turnover, tissue remodeling, and cellular behavior. Therefore, TIMPs (similar to MMPs) modulate angiogenesis, cell proliferation, and apoptosis. An interruption in the balance between MMPs and TIMPs has been implicated in the pathophysiology and progression of several diseases. This review focuses on the participation of both MMPs (e.g., MMP-2 and MMP-9) and TIMPs (e.g., TIMP-1 and TIMP-3) in physiological processes and on how their abnormal regulation is associated with human diseases. The inclusion of current strategies and mechanisms of MMP inhibition in the development of new therapies targeting MMPs was also considered.

Increased Expressions of Matrix Metalloproteinases (MMPs) in Prostate Cancer Tissues of Men with Type 2 Diabetes

Type 2 diabetes (T2D) is associated with worse prognosis of prostate cancer (PCa). The molecular mechanisms behind this association are still not fully understood. The aim of this study was to identify key factors, which contribute to the more aggressive PCa phenotype in patients with concurrent T2D. Therefore, we investigated benign and PCa tissue of PCa patients with and without diabetes using real time qPCR. Compared to patients without diabetes, patients with T2D showed a decreased E-cadherin/N-cadherin (CDH1/CDH2) ratio in prostate tissue, indicating a switch of epithelial-mesenchymal transition (EMT), which is a pivotal process in carcinogenesis. In addition, the gene expression levels of matrix metalloproteinases (MMPs) and CC chemokine ligands (CCLs) were higher in prostate samples of T2D patients. Next, prostate adenocarcinoma PC3 cells were treated with increasing glucose concentrations to replicate hyperglycemia in vitro. In these cells, high glucose induced expressions of MMPs and CCLs, which showed significant positive associations with the proliferation marker proliferating cell nuclear antigen (PCNA). These results indicate that in prostate tissue of men with T2D, hyperglycemia may induce EMT, increase MMP and CCL gene expressions, which in turn activate invasion and inflammatory processes accelerating the progression of PCa.

Retinal capillary basement membrane thickening: Role in the pathogenesis of diabetic retinopathy

Vascular basement membrane (BM) thickening has been hailed over half a century as the most prominent histological lesion in diabetic microangiopathy, and represents an early ultrastructural change in diabetic retinopathy (DR). Although vascular complications of DR have been clinically well established, specific cellular and molecular mechanisms underlying dysfunction of small vessels are not well understood. In DR, small vessels develop insidiously as BM thickening occurs. Studies examining high resolution imaging data have established BM thickening as one of the foremost structural abnormalities of retinal capillaries. This fundamental structural change develops, at least in part, from excess accumulation of BM components. Although BM thickening is closely associated with the development of DR, its contributory role in the pathogenesis of DR is coming to light recently. DR develops over several years before clinical manifestations appear, and it is during this clinically silent period that hyperglycemia induces excess synthesis of BM components, contributes to vascular BM thickening, and promotes structural and functional lesions including cell death and vascular leakage in the diabetic retina. Studies using animal models show promising results in preventing BM thickening with subsequent beneficial effects. Several gene regulatory approaches are being developed to prevent excess synthesis of vascular BM components in an effort to reduce BM thickening. This review highlights current understanding of capillary BM thickening development, role of BM thickening in retinal vascular lesions, and strategies for preventing vascular BM thickening as a potential therapeutic strategy in alleviating characteristic lesions associated with DR.

Accelerated degradation of collagen membranes in type 1 diabetic rats is associated with increased expression and production of several inflammatory molecules

BACKGROUND

Membrane durability is critical for regenerative procedures. We reported previously that type 1-like diabetes in rats accelerates the degradation of collagen membranes and we tested here whether this is associated with increased local production of inflammatory molecules as part of a diabetes-induced chronic inflammation around and within the membranes.

METHODS

Collagen membrane discs were implanted under the scalp in diabetic (streptozotocin-induced) and control rats, which were sacrificed after 2 or 3 weeks. Total RNA and proteins were isolated from the membrane and its surrounding tissues and the expression and production of six inflammatory molecules (interleukin-6 [IL-6], tumor necrosis factor alpha [TNFα], matrix metalloproteinase [MMP]-9, macrophage migration inhibitory factor [MIF], MIP-1α, and MIP-2α) was measured using real-time PCR and western blotting, respectively. Minimal histological analysis of the membranes was conducted to conform to previous studies.

RESULTS

Hyperglycemia resulted in reduced membrane thickness (by 10% to 25%) and increased mononuclear infiltrate inside the membrane. mRNA and protein levels of IL-6, TNFα, and MMP-9 were elevated in diabetic rats both 2 and 3 weeks post-surgery. The levels (both mRNA and protein) of MIF were increased at 2 weeks post-surgery and those of MIP-1α and MIP-2α at 3 weeks. There was a very good match in the temporal changes of all examined genes between the mRNA and protein levels.

CONCLUSIONS

Elevated local production of inflammatory cytokines and MMPs, together with apparent mononuclear infiltrate and increased collagenolysis confirm that hyperglycemia leads to a chronic inflammation in and around the implanted collagen membranes, which reduces membrane longevity.

MMP-2 salivary activity in type 2 diabetes mellitus patients

BACKGROUND

Type 2 diabetes mellitus (T2DM) and periodontitis are chronic inflammatory diseases with a bidirectional relationship. The uncontrolled levels of glucose in T2DM patients change the pathophysiology and balance of inflammatory mediators. Matrix Metalloproteinase-2 (MMP-2) is a zinc-dependent endopeptidase that is responsible for tissue remodeling and degradation of the extracellular matrix in periodontal tissue. Therefore, the uncontrolled levels of glucose in T2DM could lead to an imbalance in MMP-2 activity in saliva, favoring the development of periodontitis.

METHODS

Ninety-seven T2DM patients from Hospital Dr. Donato Alarcon were included in the study. Following clinical examination, the patients were classified into four groups according to the presence and degree of periodontal disease and glycemic control. Blood and whole saliva samples (WSS) were collected from each patient. Blood samples were used for Hba1c and polymorphonuclear cells count determination, while WSS were used to determine MMP-2 activity, TIMP-1 and nitrite. MMP-2 activity was determined by zymography. TIMP-1 were determined by Western blotting, and nitric oxide (NO) levels were determined by the Griess method.

RESULTS

Of the 97 patients with T2DM, 66 had periodontitis of different severities: 18 patients had mild periodontitis, 15 had moderate and 33 had severe. Salivary MMP-2 activity, HbA1c and TIMP-1 were positively correlated with the severity of periodontitis. On the other hand, the increase in HbA1c was negatively correlated with MMP-2 activity and quantity of TIMP-1 but was positively correlated with nitrite levels.

CONCLUSIONS

T2DM with glycemic uncontrol conditions, distinct clinical alterations in periodontal tissue were identified, including a decrease in the gingival redness, increased the clinical attachment loss and imbalance of MMP-2/TIMP-1, as the possible causes of disorders promoting the progression of periodontitis. Accelerated periodontitis development with poor glycemic uncontrol likely results from the altered response of host defenses and decreased activity of polymorphonuclear cells. Taken together, these findings identify MMP-2 as a promising molecular market for periodontitis.

Effect of Irbesartan on AGEs-RAGE and MMPs systems in rat type 2 diabetes myocardial-fibrosis model

IMPACT STATEMENT

There are about 425 million diabetes patients (20-79 years) in the world according to the International Diabetes Federation Diabetes Atlas - 8th Edition. The cardiovascular complication is one of the major causes of death in diabetes patients. Myocardial fibrosis is one of the serious pathological changes, so investigating the pathogenesis of myocardial fibrosis has the significant value. Our study aims to investigate the effect of Irbesartan (the angiotensin II receptor antagonist) on the changes of AGE-RAGE system and MMP family components, and analyzes the potential mechanisms in type 2 diabetes-induced myocardial fibrosis. Our results provide the theoretical base for better understanding the pathogenesis in type 2 diabetes-induced myocardial complication. It is useful for clinicians to select the effective therapeutic measures for treatment of type 2 diabetes-induced organ fibrosis.

Effect of photobiomodulation and exercise on early remodeling of the Achilles tendon in streptozotocin-induced diabetic rats

The aim of this study was to compare the treatment effects of laser photobiomodulation (LPBM) therapy and aerobic exercise on the biomechanical properties, tissue morphology and the expression of tendon matrix molecules during early remodeling of Achilles tendon (AT) injury in diabetic rats. Animals were randomly assigned to five groups: injured non diabetic (I, n = 15), injured diabetic (ID, n = 15), injured diabetic plus LPBM (IDL, n = 16), injured diabetic plus aerobic exercise (IDE, n = 16) and injured diabetic plus aerobic exercise and LPBM (IDEAL, n = 17). Type 1 diabetes was induced via a single intravenous injection of Streptozotocin at a dose of 40 mg/kg. A partial tenotomy was performed in the right AT. LPBM was performed with an indium-gallium-aluminum-phosphide 660 nm 10 mW laser device (spot size 0.04 cm2, power density 250 mW/cm2, irradiation duration 16 s, energy 0.16 J, energy density 4 J/cm2) on alternate days for a total of 9 sessions over 3 weeks (total energy 1.44 J), using a stationary contact technique to a single point over the dorsal aspect of the AT. Moderate aerobic exercise was performed on a motorized treadmill (velocity 9 m/min for 60 minutes). At 3 weeks post-injury, biomechanical analyzes as well as assessment of fibroblast number and orientation were performed. Collagen 1 (Col1) and 3 (Col3) and matrix metalloproteinases (MMPs) -3 and 13 protein distributions were studied by immunohistochemistry; while Col1 and Col3 and MMP-2 and 9 gene expression were assessed by quantitative RT-PCR (qRT-PCR). IDEAL exhibited significant increases in several biomechanical parameters in comparison to the other groups. Moreover, IDEAL presented stronger Col1 immunoreactivity when compared to ID, and weaker Col3 immunoreactivity than IDE. Both IDL and IDEAL demonstrated weaker expression of MMP-3 in comparison to I, while IDL presented no expression of MMP-13 when compared to ID. ID, IDL and IDE showed an increased number of fibroblasts in comparison to I, while IDEAL decreased the number of these cells in comparison to ID and IDE. IDL and IDEAL groups exhibited decreased angular dispersion among the fibroblasts when compared to I. The gene expression results showed that IDE demonstrated a downregulation in Col1 mRNA expression in comparison to I and ID. IDEAL demonstrated upregulation of Col1 mRNA expression when compared to IDL or IDE alone and increased MMP-2 expression when compared to IDL and IDE. MMP-9 expression was upregulated in IDEAL when compared to I, IDL and IDE. Our results suggest a beneficial interaction of combining both treatment strategies i.e., aerobic exercise and LPBM, on the biomechanical properties, tissue morphology and the expression of matrix molecules in diabetic tendons.

Serum Zn/Cu Ratio Is Associated with Renal Function, Glycemic Control, and Metabolic Parameters in Japanese Patients with and without Type 2 Diabetes: A Cross-sectional Study

BACKGROUND

Zinc (Zn) and copper (Cu) may play a pivotal role in the pathogenesis of diabetes and diabetic complications by mediating oxidative stress. Both Zn deficiency and excess of Cu are associated with an increased risk of type 2 diabetes and cardiovascular disease. We aimed to investigate the relationships between serum Zn/Cu ratio and glycemic status, renal function, and metabolic parameters in patients with and without type 2 diabetes.

METHODS

We conducted a cross-sectional study on 355 subjects (149 type 2 diabetic and 206 non-diabetic) in whom serum Zn and Cu levels were measured at the same time. Associations between serum Zn/Cu ratio and clinical data were evaluated using multiple regression analysis. We also evaluated associations between serum Zn/Cu ratio and the prevalence of type 2 diabetes and glycemic control by multivariate logistic regression analysis.

RESULTS

Serum Zn/Cu ratio was positively associated with estimated glomerular filtration rate after adjustment for body mass index (BMI) (β = 0.137, p = 0.014). Plasma B-type natriuretic peptide levels were negatively associated with serum Zn/Cu ratio after adjustment for age, sex, and BMI (β = -0.258, p = 0.032). In patients with type 2 diabetes, serum Zn/Cu ratio was negatively associated with plasma HbA1c levels after adjustment for age, sex, and BMI (β = -0.239, p = 0.003). In addition, multivariate logistic regression analysis revealed that the highest quartile of serum Zn/Cu ratio was associated with a reduced risk of poor (HbA1c ≥ 7%) glycemic control (odds ratio = 0.382; 95% confidence interval, 0.165-0.884; p = 0.025) in patients with type 2 diabetes.

CONCLUSION

Serum Zn/Cu ratio was favorably associated with renal function in all subjects and glycemic control in patients with type 2 diabetes. The Zn/Cu ratio, in addition to the individual serum levels of trace elements, is important for metabolism in humans.