Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One of the early features of diabetic retinopathy is the alteration of the blood-retinal barrier (BRB), which may involve the breakdown of endothelial cell tight junctions. The aim of this study was to examine the expression of extracellular proteinases in an animal model of early diabetic retinopathy and to determine their role in the alteration of the BRB. Matrix metalloproteinase (MMP) expression was studied in the retinas of rats with 12 weeks of diabetes. The role of MMPs in regulating tight junction function was investigated in retinal endothelial and pigment epithelial cells by measuring transepithelial electrical resistance (TER). The retinas of diabetic animals demonstrated elevated levels of MMP-2, MMP-9 and MMP-14 messenger RNA. A significant increase in the production of MMP-9 was seen when cells were exposed to high glucose conditions. Both cell types treated with purified MMP-2 or MMP-9 were found to have alterations of tight junction function as shown by decreased TER. Western blot analysis of cell extracts treated with MMP-2 or MMP-9, revealed specific degradation of the tight junction protein, occludin. Results suggest that elevated expression of MMPs in the retina may facilitate an increase in vascular permeability by a mechanism involving proteolytic degradation of the tight junction protein occludin followed by disruption of the overall tight junction complex.
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PMID:Matrix metalloproteinases in early diabetic retinopathy and their role in alteration of the blood-retinal barrier. 1571 67

Accumulation of oxidized-matrix (fibrosis) between the endothelium (the endothelial cells embedded among the myocytes) and cardiomyocytes is a hallmark of diabetes mellitus and causes diastolic impairment. In diabetes mellitus, elevated levels of homocysteine activate matrix metalloproteinase and disconnect the endothelium from myocytes. Extracellular matrix functionally links the endothelium to the cardiomyocyte and is important for their synchronization. However, in diabetes mellitus, a disconnection is caused by activated metalloproteinase, with subsequent accumulation of oxidized matrix between the endothelium and myocyte. This contributes to endothelial-myocyte uncoupling and leads to impaired diastolic relaxation of the heart in diabetes mellitus. Elevated levels of homocysteine in diabetes are attributed to impaired homocysteine metabolism by glucose and insulin and decreased renal clearance. Homocysteine induces oxidative stress and is inversely related to the expression of peroxisome proliferators activated receptor (PPAR). Several lines of evidence suggest that ablation of the matrix metalloproteinase (MMP-9) gene ameliorates the endothelial-myocyte uncoupling in diabetes mellitus. Homocysteine competes for, and decreases the PPARgammaactivity. In diabetes mellitus, endothelial-myocyte uncoupling is associated with matrix metalloproteinase activation and decreased PPARgamma activity. The purpose of this review is to discuss the role of endothelial-myocyte uncoupling in diabetes mellitus and increased levels of homocysteine, causing activation of latent metalloproteinases, decreased levels of thioredoxin and peroxiredoxin, and cardiac tissue inhibitor of metalloproteinase (CIMP) in response to antagonizing PPARgamma.
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PMID:Hyperhomocysteinemic diabetic cardiomyopathy: oxidative stress, remodeling, and endothelial-myocyte uncoupling. 1582 33

Matrix metalloproteinases (MMPs) are involved in placental remodelling throughout pregnancy. Diabetes mellitus induces alterations in tissue production of NO, a regulator of MMPs activity. The present work evaluates placental and fetal MMPs and NO levels during midpregnancy in neonatal streptozotocin-induced diabetic rats. MMP-2 and MMP-9 immunolabelling was increased both in the labyrinth zone (p<0.001) and in the giant trophoblast cells of the junctional zone (p<0.001) from diabetic placenta, when compared with controls. Also MMP-2 (p<0.01) and MMP-9 (p<0.005) activities were increased in both maternal and fetal sides of diabetic placenta when related to controls. In both sides of the diabetic placenta, nitrate/nitrite concentrations (which indicate NO production) were higher than in controls (p<0.05). An intense immunostaining for nitrotyrosine, indicating peroxynitrite-induced damage, was found in both labyrinth (p<0.001) and junctional zones (p<0.001) of diabetic placenta. Enhanced MMP-2 activity (p<0.05) and NO production were also higher in the fetuses from diabetic rats when compared to controls (p<0.005). These findings demonstrate alterations in MMPs and NO in the feto-placental unit of diabetic rats, anomalies that are likely to be involved in the developmental alterations induced by maternal diabetes.
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PMID:Increased matrix metalloproteinases 2 and 9 in placenta of diabetic rats at midgestation. 1582 20

The matrix metalloproteinase system (MMP and the TIMP inhibitors), and the ADAM metalloproteinases, have roles in maintaining vascular plaque stability and the shedding of cell surface molecules, such as TNF-alpha and adhesion molecules; aspirin suppresses MMP expression and ADAM activity from some cell lines in vitro. In a randomised prospective controlled study, we examined peripheral venous monocyte MMP-9, TIMP-1 and ADAM mRNA levels, and protein expression, in subjects with type 2 diabetes (n=10) and controls (n=14) before and after oral aspirin therapy (150mg daily for 14 days) or no active intervention. Baseline monocyte TIMP-1 mRNA levels were significantly lower in the diabetes group (p=0.0014), although monocyte MMP-9 mRNA, and MMP-9 and TIMP-1 protein expression after culture did not differ significantly between groups. Plasma MMP-9 (p=0.027) and TIMP-1 (p=0.016) concentrations were significantly greater, and the ratio of plasma TIMP-1:MMP-9 concentrations significantly lower, in the diabetes group (p=0.023). ADAM mRNA levels did not differ significantly between groups and oral aspirin therapy had no significant effect on any variable. Type 2 diabetes is characterised by reduced monocyte TIMP-1 mRNA levels, and a lower plasma MMP-9 to TIMP-1 protein ratio compared to controls, a pattern that would promote coronary plaque instability if reproduced within vascular plaque. Monocyte ADAM mRNA levels do not differ between group and oral aspirin has no significant effect on these variables.
Diabetes Res Clin Pract 2006 Jan
PMID:Monocyte matrix and ADAM metalloproteinase expression in type 2 diabetes after aspirin therapy. 1602 59

Degradation of extracellular matrix proteins by matrix metalloproteinases (MMPs) is integral to cell migration and tissue remodeling in diabetes mellitus and its complications. MMPs also regulate the function of leukocytes via proteolytic processing of cytokines/chemokines. In this study, we measured the production of MMP-9 and its natural tissue inhibitor (TIMP)-1 by leukocytes isolated from human type I diabetic patients. MMP-9 was also detected in serum and splenocytes from non-obese diabetic (NOD) and BALB/c mice. MMP-9 was markedly elevated in leukocytes from diabetics compared to non-diabetic controls. TIMP-1 production was also enhanced in leukocytes from diabetics, but substantially less than MMP-9, with the MMP-9/TIMP-1 ratio being 1.6-fold higher in neutrophils and 3-fold higher in monocytes than controls. Interleukin (IL)-2 or lipopolysaccharide (LPS) treatment increased MMP-9 production in leukocytes from both diabetics and normal controls, whereas insulin decreased MMP-9 expression. Recombinant MMP-9 stimulated the proliferation of mouse splenocytes from NOD or BALB/c and a MMP-9 inhibitor dose-dependently inhibited splenocyte proliferation. In conclusion, our results demonstrate firstly that MMP-9 expression is elevated in leukocytes from type I diabetic patients and NOD mice and secondly, that MMP-9 elevates proliferation of mouse splenocytes. These data suggest that elevated leukocyte MMP-9 may contribute to the pathogenesis of type I diabetes and its associated complications.
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PMID:Leukocyte matrix metalloproteinase-9 is elevated and contributes to lymphocyte activation in type I diabetes. 1605 58

Matrix metalloproteinases (MMPs) 2 and 9 are responsible for extracellular matrix breakdown and their abnormal circulating levels may pre-date clinical evidence of diabetic angiopathy. We detected by ELISA, plasma MMP-2 and MMP-9 levels and associated activity in 25 children and adolescents with T1DM. Thirteen male and 12 female patients were evaluated at the clinical diagnosis and onset of T1DM and again at a 5-year follow-up. Twelve patients had developed microangiopathic complications at the follow-up evaluation. MMP-2 and MMP-9 levels and activity were detected in samples obtained at T1DM diagnosis and at the 5-year follow-up. As controls, 19 healthy subjects who were the same age as the patients were also evaluated at baseline and again after 5 years. MMP-2 levels and activity were significantly higher in the patients than in the controls at disease onset. This was particularly evident when patients who developed microangiopathic complications were compared to controls and patients without complications. At the 5-year follow-up, a significant increase in MMP-2 levels and a significant decrease in MMP-2 activity were found only in the control group compared to the baseline levels. MMP-2 levels and activity were higher in patients with microangiopathy. MMP-9 levels and activity were increased in all groups compared to baseline levels. MMP-9 levels were lower in patients with microangiopathy compared to controls, but no difference was found between the two patient groups. It is well known that MMP-9 is an index of the severity and stability of macroangiopathy while our results allow us to postulate that MMP-2 may be a marker of microangiopathy.
Diabetes Res Clin Pract 2005 Nov
PMID:Matrix metalloproteinase 2 may be a marker of microangiopathy in children and adolescents with type 1 diabetes mellitus. 1618 74

Increased levels of metalloproteinase (MMP)-9 have been shown in hypertensive patients. Lercanidipine is a calcium channel blocker with antioxidant actions. We examined whether lercanidipine produces antioxidant effects and reduces MMP-9 activity in hypertensive patients in a placebo-controlled, crossover, single-blinded design study including 18 healthy volunteers (control group), and 14 hypertensive patients without (N = 7) or with (N = 7) diabetes mellitus. Hypertensive patients were randomized to treatment with placebo (15 days) or lercanidipine 20 mg/d (15 days). Arterial blood pressure was evaluated with ambulatory blood pressure monitoring. Plasma thiobarbituric acid reactive species (TBA-RS) levels were measured to assess oxidative stress, and plasma MMP-2 and MMP-9 were assayed by gel zymography before and after treatment with placebo or lercanidipine. Plasma concentrations of tissue inhibitor of metalloproteinases (TIMP)-1 were measured by ELISA. Lercanidipine reduced mean arterial pressure by 7% in hypertensive patients without diabetes (P < 0.05), but not in hypertensive patients with diabetes. It significantly decreased plasma TBA-RS levels in hypertensive patients without and with diabetes (95% confidence interval [CI], -26 to -46%, P = 0.048, and -22 to -33%, P = 0.036, respectively). In addition, lercanidipine decreased activated MMP-9 in hypertensive patients without and with diabetes (95% CI, -19 to -47%, P = 0.047, and -80 to -96%, P = 0.010, respectively). No effects were seen on MMP-2. No significant differences or changes in plasma TIMP-1 concentrations were found. Therefore, we demonstrate for the first time that lercanidipine consistently decreased MMP-9 activity and reduced oxidative stress in hypertensive patients, thus suggesting a mechanism probably involved in the pleotropic actions of lercanidipine.
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PMID:Lercanidipine reduces matrix metalloproteinase-9 activity in patients with hypertension. 1642 95

Calcification of vascular elastin occurs in patients with arteriosclerosis, renal failure, diabetes, and vascular graft implants. We hypothesized that pathological elastin calcification is related to degenerative and osteogenic mechanisms. To test this hypothesis, the temporal expression of genes and proteins associated with elastin degradation and osteogenesis was examined in the rat subdermal calcification model by quantitative real-time reverse transcription-polymerase chain reaction and specific protein assays. Purified elastin implanted subdermally in juvenile rats exhibited progressive calcification in a time-dependent manner along with fibroblast and macrophage infiltration. Reverse transcription-polymerase chain reaction analysis showed that relative gene expression levels of matrix metalloproteinases (MMP-2 and MMP-9) and transforming growth factor-beta1 were increased in parallel with calcification. Gelatin zymography showed strong MMP activities at early time points, which were associated with high levels of soluble elastin peptides. Gene expression of core binding factor alpha-1, an osteoblast-specific transcription factor, increased in parallel with elastin calcification and attained approximately 9.5-fold higher expression at 21 days compared to 3 days after implantation. Similarly, mRNA levels of the bone markers osteopontin and alkaline phosphatase also increased progressively, but osteocalcin levels remained unchanged. We conclude that degenerative and osteogenic processes may be involved in elastin calcification.
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PMID:Elastin calcification in the rat subdermal model is accompanied by up-regulation of degradative and osteogenic cellular responses. 1643 63

Exposure to arsenic in drinking water is associated with an increased rate of lung cancer. The objective of this study was to determine whether arsenic exposure at relatively low concentrations (approximately 20 microg/L) is associated with changes in biomarkers of lung inflammation, as measured by the ratio of sputum metalloproteinase and antiproteinase activity. A total of 73 subjects residing in Ajo and Tucson, Arizona were recruited for this cross-sectional study. Tap water and first morning void urine were analyzed for arsenic. Matrix metalloproteinase 2 (MMP-2), 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) were measured in induced sputum. Household tap water arsenic levels in Ajo (20.3+/-3.7 microg/L) were higher than in those Tucson (4.0+/-2.3 microg/L), as were mean urinary total inorganic arsenic levels (29.1+/-20.4 and 11.0+/-12.0 microg/L, respectively). Log-normalized MMP-2, MMP-9, and TIMP-1 concentrations in sputum were not significantly different between towns. However, after adjusting for town, asthma, diabetes, urinary monomethylarsonic acid/inorganic arsenic, and smoking history, total urinary arsenic was negatively associated with MMP-2 and TIMP-1 levels in sputum and positively associated with the ratio of MMP-2/TIMP-1 and MMP-9/TIMP-1 in sputum. Increased sputum proteinase/antiproteinase activity suggests a potential toxic mechanism for low-level arsenic exposure.
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PMID:Environmental arsenic exposure and sputum metalloproteinase concentrations. 1648 58

The role of ubiquitin-proteasome system in the accelerated atherosclerotic progression of diabetic patients is unclear. We evaluated ubiquitin-proteasome activity in carotid plaques of asymptomatic diabetic and nondiabetic patients, as well as the effect of rosiglitazone, a peroxisome proliferator-activated receptor (PPAR)-gamma activator, in diabetic plaques. Plaques were obtained from 46 type 2 diabetic and 30 nondiabetic patients undergoing carotid endarterectomy. Diabetic patients received 8 mg rosiglitazone (n = 23) or placebo (n = 23) for 4 months before scheduled endarterectomy. Plaques were analyzed for macrophages (CD68), T-cells (CD3), inflammatory cells (HLA-DR), ubiquitin, proteasome 20S activity, nuclear factor (NF)-kappaB, inhibitor of kappaB (IkappaB)-beta, tumor necrosis factor (TNF)-alpha, nitrotyrosine, matrix metalloproteinase (MMP)-9, and collagen content (immunohistochemistry and enzyme-linked immunosorbent assay). Compared with nondiabetic plaques, diabetic plaques had more macrophages, T-cells, and HLA-DR+ cells (P < 0.001); more ubiquitin, proteasome 20S activity (TNF-alpha), and NF-kappaB (P < 0.001); and more markers of oxidative stress (nitrotyrosine and O2(-) production) and MMP-9 (P < 0.01), along with a lesser collagen content and IkappaB-beta levels (P < 0.001). Compared with placebo-treated plaques, rosiglitazone-treated diabetic plaques presented less inflammatory cells (P < 0.01); less ubiquitin, proteasome 20S, TNF-alpha, and NF-kappaB (P < 0.01); less nitrotyrosine and superoxide anion production (P < 0.01); and greater collagen content (P < 0.01), indicating a more stable plaque phenotype. Similar findings were obtained in circulating monocytes obtained from the two groups of diabetic patients and cultured in the presence or absence of rosiglitazone (7.0 micromol/l). Ubiquitin-proteasome over-activity is associated with enhanced inflammatory reaction and NF-kappaB expression in diabetic plaques. The inhibition of ubiquitin-proteasome activity in atherosclerotic lesions of diabetic patients by rosiglitazone is associated with morphological and compositional characteristics of a potential stable plaque phenotype, possibly by downregulating NF-kappaB-mediated inflammatory pathways.
Diabetes 2006 Mar
PMID:The ubiquitin-proteasome system and inflammatory activity in diabetic atherosclerotic plaques: effects of rosiglitazone treatment. 1650 24


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