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)

Diabetes increases susceptibility to chronic ulceration. The cause of chronic wound formation in diabetic individuals is multifactorial but may be accelerated by changes in the structure and function of the skin secondary to impaired fibroblast proliferation, decreased collagen synthesis, and increased matrix metalloproteinase (MMP) expression. This study explored cellular and biochemical changes in organ cultures of skin from streptozotocin-diabetic (STZ-D) rats and the effects of all-trans retinoic acid (RA) on these changes. STZ-D rats were killed after 6 weeks. The skin was cut into 2-mm pieces and incubated in organ culture for 3 or 6 days in the absence or presence of 3 micromol/l RA. After organ culture incubation, control and RA-treated tissue was examined histologically after staining with hematoxylin and eosin. In parallel, organ culture-conditioned medium was assayed for MMPs. Additional organ cultures were examined for collagen synthesis using (3)H-proline incorporation into trichloroacetic acid-precipitable material and for glycosaminoglycan production based on interaction with the cationic dye 1,9-dimethylmethylene blue and by staining of tissue sections with periodic acid Schiff reagents. Skin from 6-week STZ-D rats demonstrated features of dermal atrophy including thinning and disorganization of connective tissue bundles and increased space between bundles. The addition of RA resulted in cellular reactivation and partially reversed the histological features of dermal atrophy. Levels of latent and active MMP-9 and MMP-13 were elevated 4- and 10-fold, respectively, in STZ-D skin and reduced by 50-75% (P < 0.05) by RA. Collagen synthesis was increased by 30% (P < 0.05) by RA, whereas glycosaminoglycan expression was increased by only 9% (NS). RA also increased proliferation of STZ-D skin fibroblasts (approximately threefold over control; P < 0.05). Together, these data suggest that RA has the capacity to improve structure and function of diabetic skin.
Diabetes 2002 Dec
PMID:All-trans retinoic acid improves structure and function of diabetic rat skin in organ culture. 1245 8

Circulating and vascular endothelin-1 (ET-1) levels are elevated in diabetes, but the molecular components of the enzymatic activation of ET-1 in the vasculature remains unknown. Furthermore, the distribution of ET receptors favors a contractile phenotype in African Americans with diabetes. Whether there is any difference in local ET-1 activation in this population is unknown. This study examined the expression and activity of ET converting enzyme-1 subisoforms (ECE-1) in the internal mammary artery specimens obtained from patients undergoing coronary artery bypass grafting. The study groups included African-American (AA) and Caucasian (CA), nondiabetic (ND) and diabetic (D) patients: AAND N = 10, CAND N = 9, AAD N = 9, and CAD N = 11. The expression of ECE-1 a, ECE-1 b and ECE-1c subisoforms was studied by RT-PCR. ECE-1 a was upregulated 2- and 4-fold in the CAD and MD groups, respectively (P < .05). In African-American patient groups, ECE-1 activity (fmol/ mg protein.h) was augmented from 2,804 +/- 185 in nondiabetic tissue samples to 6,857 +/- 393 in the diabetic tissue (P < .05). There was a similar increase in the CAD group, which did not significantly differ from AA diabetics. ECE-1 inhibitors, phosphoramidon and FR-901533, inhibited vascular ECE-1 activity by more than 80%. While neutral endopeptidase (NEP) and matrix metalloproteinase-2 (MMP-2) are able to process big ET-1, inhibitors of NEP (thiorphan) and MMP (batimistat) did not affect ECE-1 activity. In conclusion, the enzymatic pathway essential for generating vascular ET-1 is activated in the vasculature of both AA and CA diabetic patients and this activation is highly specific for ECE-1.
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PMID:Vascular endothelin converting enzyme-1 expression and activity is upregulated in clinical diabetes. 1247 47

Although it is known that systemic diseases such as diabetes result in impaired wound healing, the mechanism for this impairment is not understood. Because fibroblasts are essential for wound repair, we compared the in vitro behavior of fibroblasts cultured from diabetic, leptin receptor-deficient (db/db) mice with wild-type fibroblasts from mice of the same genetic background in processes important during tissue repair. Adult diabetic mouse fibroblast migration exhibited a 75% reduction in migration compared to normal fibroblasts (P < 0.001) and was not significantly stimulated by hypoxia (1% O(2)), whereas wild-type fibroblast migration was up-regulated nearly twofold in hypoxic conditions (P < 0.05). Diabetic fibroblasts produced twice the amount of pro-matrix metalloproteinase-9 as normal fibroblasts, as measured by both gelatin zymography and enzyme-linked immunosorbent assay (P < 0.05). Adult diabetic fibroblasts exhibited a sevenfold impairment in vascular endothelial growth factor (VEGF) production (4.5 +/- 1.3 pg/ml versus 34.8 +/- 3.3 pg/ml, P < 0.001) compared to wild-type fibroblasts. Moreover, wild-type fibroblast production of VEGF increased threefold in response to hypoxia, whereas diabetic fibroblast production of VEGF was not up-regulated in hypoxic conditions (P < 0.001). To address the question whether these differences resulted from chronic hyperglycemia or absence of the leptin receptor, fibroblasts were harvested from newborn db/db mice before the onset of diabetes (4 to 5 weeks old). These fibroblasts showed no impairments in VEGF production under basal or hypoxic conditions, confirming that the results from db/db fibroblasts in mature mice resulted from the diabetic state and were not because of alterations in the leptin-leptin receptor axis. Markers of cellular viability including proliferation and senescence were not significantly different between diabetic and wild-type fibroblasts. We conclude that, in vitro, diabetic fibroblasts show selective impairments in discrete cellular processes critical for tissue repair including cellular migration, VEGF production, and the response to hypoxia. The VEGF abnormalities developed concurrently with the onset of hyperglycemia and were not seen in normoglycemic, leptin receptor-deficient db/db mice. These observations support a role for fibroblast dysfunction in the impaired wound healing observed in human diabetics, and also suggest a mechanism for the poor clinical outcomes that occur after ischemic injury in diabetic patients.
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PMID:Cellular dysfunction in the diabetic fibroblast: impairment in migration, vascular endothelial growth factor production, and response to hypoxia. 1250 13

Statins exert pleiotropic effects on several other cellular functions besides lipid-lowering. Previously, it was found that cerivastatin is a very potent inhibitor of human arterial smooth muscle cell (haSMC) growth. However, because increased extracellular matrix (ECM) synthesis also accounts mainly for intimal plaque formation, the effects of cerivastatin on ECM expression was examined in this study. Furthermore, the influence of varying glucose and low-density lipoprotein (LDL) levels on cerivastatin-treated haSMCs was analyzed to mimic the conditions in patients with diabetes or hypercholesterolemia. The haSMCs were treated with 0.001-5.0 microM cerivastatin in the presence of 5.5-18.9 m glucose and 10-1000 microg/ml LDL. After 3 days, the messenger RNA (mRNA) expression of eight ECM proteins was analyzed and, after 7 days, mitotic and mitochondrial activities and thrombospondin (TSP)-1 protein expression were analyzed. TSP-1 and TSP-2 mRNA expression was inhibited highly significantly at cerivastatin doses >or=0.01 microM with maximums of 72% and 35%, respectively, at high glucose levels. The mRNA signals of the third glycoprotein fibronectin were not influenced. Furthermore, collagen-1 mRNA was inhibited highly significantly up to 71% and biglycan mRNA was similarly inhibited up to 45%. The mRNA expression of the matrix-stimulating transforming growth factor (TGF)-beta1 and matrix metalloproteinase (MMP)-2 was not altered significantly, whereas mRNA expression of the tissue inhibitor of metalloproteinase (TIMP)-2 was stimulated clearly up to 150%. Mevalonate, but not LDL replacement, reversed the effects. Immunofluorescence staining showed an unaltered TSP-1 pattern with cerivastatin doses up to 0.1 microM whereas higher doses impaired TSP-1 excretion. The effects of cerivastatin on haSMC growth and mRNA expression of the eight ECM components were not diminished by the increase in LDL and glucose levels. Since accelerated SMC growth and ECM formation contribute mainly to intimal thickening, cerivastatin may be protective against the development of atherosclerotic and restenotic lesions by its direct cellular effects. Increased LDL and glucose levels, as in diabetes, do not mitigate the beneficial effects of cerivastatin on cell growth and ECM formation in vitro.
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PMID:Effects of cerivastatin on human arterial smooth muscle cell growth and extracellular matrix expression at varying glucose and low-density lipoprotein levels. 1260 21

In cultured human glomerular epithelial cells (HGEC), 25 mM glucose resulted in decreased expression of alpha(3)-, alpha(2)-, and beta(1)-integrins and increased expression of alpha(5)- and alpha(v)beta(3)-integrins. This change was accompanied by decreased binding of HGEC to type IV collagen. In the presence of normal (5 mM) glucose concentration, cell binding to type IV collagen was primarily mediated by alpha(2)beta(1)- and alpha(5)beta(1)-integrins, as indicated by experiments in which cell adhesion to type IV collagen was competed by specific anti-integrin monoclonal antibodies. In the presence of high (25 mM) glucose, the upregulated alpha(5)- and alpha(v)beta(3)-integrins were mainly involved in cell binding to type IV collagen. Furthermore, high glucose decreased expression of matrix metalloproteinase-2 (MMP-2), a collagenase regulated in part by alpha(3)beta(1)-integrin, as suggested by the use of ligand-mimicking antibodies against these integrins, which resulted in release of increased amounts of MMP-2 in the culture medium. Finally, tissue inhibitor of metalloproteinase-2, the specific inhibitor of MMP-2, was upregulated in high glucose and could contribute to matrix accumulation. These changes could help explain basement membrane thickening in diabetes.
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PMID:Glucose-induced changes in integrins and matrix-related functions in cultured human glomerular epithelial cells. 1262 Sep 21

Genetic, endocrine, and environmental factors contribute to the development of diabetes. Much information has been gathered on the homeostasis mechanisms of glucose regulation by insulin-producing pancreatic beta cells. Here we demonstrate high expression levels of gelatinase B (matrix metalloproteinase-9, MMP-9) by neutrophils in acute pancreatitis and by ductular epithelial cells in chronic pancreatitis. Because gelatinase B processes cytokines and chemokines, we investigated whether and how gelatinase B cleaves insulin. Pure human neutrophil gelatinase B was found to destroy insulin by cleavage at 10 sites. Pancreatic islet and ductular cells are relatively spared in comparison with the complete destruction of acinar cells of the exocrine pancreas in chronic pancreatitis. High expression levels of gelatinase B are maintained in the immediate proximity of insulin-secreting beta cells. Consequently, diabetes may be worsened by enzymatic degradation of insulin by gelatinase B and by the consequent enhancement of the autoimmune process. Gelatinase B is diabetogenic in acute and chronic pancreatitis by cleaving insulin.
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PMID:Gelatinase B is diabetogenic in acute and chronic pancreatitis by cleaving insulin. 1262 33

Accumulation of oxidized-matrix between the endothelium and myocytes is associated with endocardial endothelial (EE) dysfunction in diabetes and heart failure. High levels of circulating homocysteine (Hcy) have been demonstrated in diabetes mellitus (DM). These high levels of Hcy (hyperhomocysteinemia, HHcy) have a negative correlation with peroxisome proliferator activated receptor (PPAR) expression. Studies have demonstrated that Hcy decreases bioavailability of endothelial nitric oxide (eNO), generates nitrotyrosine, and activates latent matrix metalloproteinase (MMP), instigating EE dysfunction. PPAR ligands ameliorate endothelial dysfunction and DM. In addition Hcy competes with PPAR ligands. The understanding of molecular, cellular, and extracellular mechanisms by which Hcy amplifies DM will have therapeutic ramifications for diabetic cardiomyopathy.
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PMID:Role of nitric oxide in matrix remodeling in diabetes and heart failure. 1265 56

Diabetes is a major risk factor for atherosclerosis. Hyperglycemia is an underlying contributing factor; however, the mechanisms that mediate the vascular complications are not yet fully understood. In the present study, we provide evidence that elevated glucose induces discordant matrix metalloproteinase (MMP) expression from two key vascular cells, endothelial cells and macrophages. Our results clearly indicate that high glucose (25 mM) induced endothelial cell expression and activity of the collagenase, MMP-1 and the gelatinase, MMP-2, whilst reducing expression of the stromelysin, MMP-3 (P<0.05). Similarly, our results show that high glucose (25 mM) induces expression and activity of MMP-9 from monocyte-derived macrophages (P<0.05). High glucose culture did not affect metalloproteinase inhibitor (TIMP-1) expression. Our results suggest for the first time that high glucose exposure induced discordant regulation of the MMP/TIMP system in vascular cells. The increased MMP-1, MMP-2 and MMP-9 activities induced by high glucose exposure could promote matrix degradation thereby accelerating atherogenesis and potentially reducing plaque stability in diabetes.
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PMID:High glucose alters matrix metalloproteinase expression in two key vascular cells: potential impact on atherosclerosis in diabetes. 1280 9

We have employed microarray technology using RNA from normal 3T3-L1 adipocytes and from 3T3-L1 adipocytes made insulin-resistant by treatment with tumor necrosis factor-alpha to identify a new class of insulin-responsive genes. These genes continued to respond normally to insulin even though the adipocytes themselves were metabolically insulin-resistant, i.e. they displayed a significantly decreased rate of insulin-stimulated glucose uptake. Approximately 12,000 genes/expressed sequence tags (ESTs) were screened. Of these, 40 genes/ESTs were identified that became insulin-resistant as expected (e.g. Socs-3, junB, and matrix metalloproteinase-11). However, 61 genes/ESTs continued to respond normally to insulin. Although some of these genes were previously shown to be regulated by insulin (e.g. Glut-1 and beta3-adrenergic receptor), other novel insulin-sensitive genes were also identified (e.g. Egr-1, epiregulin, Fra-1, and ABCA1). Real-time reverse transcription-PCR analysis confirmed the expression patterns of several of the differentially expressed genes. One gene that remained insulin-sensitive in the insulin-resistant adipocytes is the transcription factor Egr-1. Using an antisense strategy, we show that tissue factor and macrophage colony-stimulating factor, two cardiovascular risk factors, are downstream EGR-1 target genes in the adipocyte. Taken together, these data support the hypothesis that some signaling pathways remain insulin-sensitive in metabolically insulin-resistant adipocytes. These pathways may promote abnormal gene expression in hyperinsulinemic states like obesity and type II diabetes and thus may contribute to pathologies associated with these conditions.
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PMID:Expression profiling identifies genes that continue to respond to insulin in adipocytes made insulin-resistant by treatment with tumor necrosis factor-alpha. 1453 Feb 83

Patients with diabetes mellitus (DM) may develop chronic inflammatory demyelinating polyneuropathy (CIDP), which may be difficult to distinguish from diabetic neuropathy (DNP). Here the authors show that immunoreactivity for matrix metalloproteinase-9 on sural nerve biopsies may help to identify CIDP-DM. In a pilot study on 10 CIDP-DM patients with IV immunoglobulins and tight glycemic control, the CIDP-DM patients had a better outcome than DNP patients treated with tight glycemic control only.
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PMID:Diagnostic value of sural nerve matrix metalloproteinase-9 in diabetic patients with CIDP. 1466 52


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