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)

OT is a relevant biological pathway for generating peripheral tolerance against both self and external antigens with minimal side effects (fig. 3). This route might, therefore, contain promising potential for the treatment of autoimmune and allergic diseases in the human (fig. 3). Thus, oral administration of autoantigens suppresses experimental autoimmune diseases (EAE, EAU, AA, collagen-induced arthritis, NOD diabetes) in a disease- and antigen-specific manner, and oral administration of alloantigens has led to increase of allograft survival. OT might be important in treatment of immune complex diseases and food allergies. OT is mediated by T lymphocytes using at least two nonmutually exclusive mechanisms: suppression and anergy. Suppression can be adoptively transferred by CD8+ T lymphocytes which act by releasing TGF-beta and IL-4 following antigen-specific triggering. Antigen-driven tissue-directed suppression occurs following oral administration of an antigen from the target organ, even if it is not the disease-inducing antigen (bystander suppression). Thus, synthetic peptides can induce OT, and tolerogenic epitopes of antigen may be different from the autoreactive epitope. Due to the promising results in animal models, OT is being tested in clinical trials in multiple sclerosis, rheumatoid arthritis and uveitis [193, 194].
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PMID:Oral tolerance: a biologically relevant pathway to generate peripheral tolerance against external and self antigens. 801 Nov 55

Evaluations of glomerular mRNA levels encoding for PCNA, TNF-alpha, PDGF-A and -B chains, TGF-beta, IGF-I, bFGF, and EGF were made at 4, 12, and 24 wk after injection of STZ in Sprague-Dawley rats. The mRNA levels for PCNA, TNF-alpha, PDGF-B chain, TGF-beta, and bFGF increased with age in STZ-induced diabetic rats. At 24 wk after STZ injection, mRNA levels for PCNA, TNF-alpha, PDGF-B chain, TGF-beta, and bFGF were increased 3.8-fold, (P < 0.01), 4.2-fold (P < 0.01), 4.0-fold (P < 0.01), 5.2-fold (P < 0.001), and 3.6-fold (P < 0.01), respectively, in the glomeruli of diabetic rats when compared with control rats. In contrast, mRNA levels for IGF-I, PDGF-A chain, and EGF were not altered in glomeruli from diabetic and control rats throughout the experimental period. Insulin treatment partially ameliorated the increase in mRNA levels for PCNA, TNF-alpha, PDGF-B chain, TGF-beta, and bFGF in the glomeruli of diabetic rats. These data indicate that alterations in growth factor mRNA levels in glomeruli may be a manifestation of diabetic nephropathy, and that hyperglycemia or insulin deficiency may play a role in abnormal growth factor gene regulation.
Diabetes 1993 Mar
PMID:mRNA expression of growth factors in glomeruli from diabetic rats. 809 59

In vitro glomerular collagen synthesis and its response to various concentrations of transforming growth factor-beta 1 were studied in normal and diabetic rats. TGF-beta 1 increased collagen synthesis in normal glomeruli in a dose-dependent manner up to 5 ng/ml. Concentrations > 5 ng/ml showed a gradual decline in collagen synthesis. Basal collagen synthesis was increased in diabetic glomeruli, but addition of TGF-beta 1 had no effect. Antibody to TGF-beta 1 prevented this increase in collagen synthesis. Both circulating TGF-beta 1 concentration and its glomerular expression of mRNA were higher in diabetic than in normal rats. Although addition of TGF-beta 1 did not increase synthesis in vitro, the absence of an effect is consistent with downregulation of its receptors attributable to the high circulating levels. This study clearly indicates a regulatory role of TGF-beta 1 in renal glomerular collagen synthesis in the normal rat, and suggests a possible causal role for enhanced collagen synthesis in the diabetic rat.
Diabetes 1993 Nov
PMID:Transforming growth factor-beta 1 enhances glomerular collagen synthesis in diabetic rats. 840 11

Expansion of the mesangial matrix in diabetes occurs after prolonged exposure to the diabetic milieu. To mimic the long-term hyperglycemia of diabetes mellitus we developed tissue culture systems that might approximate the chronic state. This was accomplished in two ways: (1) by growing mesangial cells on extracellular matrix glycated and crosslinked in vitro and (2) by continuously growing cells on their own matrix on filters in elevated glucose medium (500 mg/dl) for up to eight weeks without passage. Synthesis of collagen and proteoglycans was evaluated in cells grown under these conditions. In both these situations, 3H-proline incorporation into collagenase sensitive protein and 35S incorporation into sulfated proteins were reduced compared to control cultures. Despite reduction in 35S incorporation into proteoglycans in the high glucose cultures, total glycosaminoglycan content was unchanged. However, proteoglycans generated by mesangial cells grown in elevated glucose media were of a lower negative charge than controls. In mesangial cells continuously grown on filters, the levels of messenger RNA for collagen types I and IV, biglycan and TGF-beta were not different in cells grown at elevated or standard glucose concentrations for two and four weeks. We conclude that crosslinking of mesangial matrix or continuous culture of cells for prolonged periods of time in high glucose medium, which may also crosslink matrix, suppresses collagen synthesis and reduces the negative charges on matrix proteoglycans without altering mRNA levels.
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PMID:Nonenzymatic glycation of mesangial matrix and prolonged exposure of mesangial matrix to elevated glucose reduces collagen synthesis and proteoglycan charge. 847 21

The actions of transforming growth factor-beta isoforms as potent regulators of growth and differentiation have led to the examination of their presence in the human pancreas. The cellular localization of TGF-beta 1, TGF-beta 2, and TGF-beta 3 was assessed in the normal human pancreas by using immunohistochemical and in situ hybridization techniques. Although cytoplasmic immunoreactivity for TGF-beta 1, TGF-beta 2, and TGF-beta 3 was found in islet cells, acinar cells, and ductal cells, a differential immunostaining pattern for TGF-beta isoforms was observed. In the endocrine pancreas, the islet cells demonstrated diffuse cytoplasmic immunostaining for TGF-beta 1, TGF-beta 2, and TGF-beta 3. However, only TGF-beta 2 and TGF-beta 3 exhibited an intense pattern of immunostaining in a few endocrine cells. Most of the positive islet cells coexpressed insulin. In contrast, in the exocrine pancreas, a greater number of acinar cells showed immunoreactivity for TGF-beta 1 than for TGF-beta 2 and TGF-beta 3. In the ductal cells, all three TGF-beta isoforms showed a similar intensity and pattern of immunostaining and were observed more frequently in the smaller distal ductules than in the larger pancreatic ducts. TGF-beta 1 and TGF-beta 3, but not TGF-beta 2, immunostaining was detected strongly in the smooth muscle cells and weakly in the endothelial cells of the blood vessels, whereas the fibroblasts of the interstitium were completely negative. In situ hybridization revealed that mRNA encoding all three TGF-beta isoforms colocalized with their respective proteins in islets, acinar cells, and ductal cells. In contrast, mRNA expression was absent in the smooth muscle cells and endothelium of the vessels. These results suggest that TGF-beta isoforms may act by both autocrine and paracrine mechanisms in the pancreas. The differential pattern of expression observed for each TGF-beta isoform implies unique roles for these proteins in the regulation of the endocrine and exocrine pancreas.
Diabetes 1993 May
PMID:Synthesis and expression of transforming growth factor beta-1, beta-2, and beta-3 in the endocrine and exocrine pancreas. 848 32

Diabetic nephropathy is characterized by renal hypertrophy, thickening of basement membranes, and accumulation of extracellular matrix in the glomerular mesangium and the interstitium. Our previous investigations have shown that high glucose concentration increases transforming growth factor (TGF)-beta1 mRNA in mesangial and proximal tubule cells and that treatment with anti-TGF-beta antibody results in prevention of the effects of high glucose on cell growth (e.g., induction of cellular hypertrophy) and the stimulation of collagen biosynthesis. We evaluated in vivo the functional role of the renal TGF-beta system in diabetic kidney disease by treatment of streptozotocin-induced diabetic mice with either a neutralizing monoclonal antibody against TGF-beta1, -beta2, and -beta3 (alphaT) or nonimmune murine IgG for 9 days. Diabetic mice given IgG demonstrated total kidney and glomerular hypertrophy, significantly elevated urinary TGF-beta1 protein, and increased mRNAs encoding TGF-beta1, type II TGF-beta receptor, alpha1(IV) collagen, and fibronectin. Treatment of diabetic mice with alphaT prevented glomerular hypertrophy, reduced the increment in kidney weight by approximately 50%, and significantly attenuated the increase in mRNA levels without having any effect on blood glucose. The antibody was without significant effect on mRNA levels in nondiabetic mice. This is the first demonstration that the early characteristic features of diabetic renal involvement, which include hypertrophy and increased matrix mRNAs, are largely mediated by increased endogenous TGF-beta activity in the kidney and that they can be significantly attenuated by treatment with neutralizing anti-TGF-beta antibodies.
Diabetes 1996 Apr
PMID:Neutralization of TGF-beta by anti-TGF-beta antibody attenuates kidney hypertrophy and the enhanced extracellular matrix gene expression in STZ-induced diabetic mice. 860 76

Decreased systemic immune responsiveness to a specific antigen following exposure to that antigen by the enteric route is termed 'oral tolerance.' Oral tolerance is revealed when attempts are made to parenterally immunize the host to the same antigen that was previously administered orally or intragastrically. A similar phenomenon is also seen following antigen exposure via the nasal mucosa and a related phenomenon is seen following antigen exposure in the upper respiratory tract. There has been a marked renewal of interest in the mechanisms that underlie oral tolerance because of its potential role for preventing and treating autoimmune and inflammatory diseases and IgE-mediated allergic disorders. The specific factors that determine whether or not the host develops mucosal tolerance to an antigen administered by the mucosal route are also of substantial importance for those involved in mucosal vaccine development. Furthermore, putative abnormalities in the ability of the host to develop mucosal tolerance may play a pathogenetic role in certain autoimmune and allergic diseases and disorders. Several well-defined immunological mechanisms mediate oral tolerance. These include the induction, following mucosal antigen exposure, of regulatory populations of T-cells that can down-regulate specific immune responses (e.g. DTH) via the production of specific cytokines (e.g. TGF-beta 1, IL-10 and IL-4). In addition, clonal anergy, clonal deletion and antibody-mediated suppression can be shown to play a role in the induction and maintenance of mucosal tolerance in several experimental systems. In animal studies, the onset of collagen-induced, adjuvant-induced, antigen-induced and pristane-induced arthritis has been delayed and the severity of ongoing disease diminished following feeding collagen type II. Mucosal tolerance has been clearly demonstrated in humans and clinical studies have been undertaken to treat rheumatoid arthritis using a similar approach. Results of initial clinical studies in rheumatoid arthritis indicated a modest improvement and further studies are ongoing in this and other autoimmune diseases (e.g. multiple sclerosis, autoimmune uveitis and insulin-dependent diabetes). This approach, if successful, could offer a new and novel therapeutic modality for preventing autoimmune and allergic disorders, and modulating ongoing disease.
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PMID:Oral tolerance: mechanisms and possible role in inflammatory joint diseases. 867 48

Transforming growth factor-beta 1 (TGF-beta 1) is a primary determinant of the mesangial expansion observed in diabetic nephropathy. In this study, we quantitated the levels of intraglomerular TGF-beta 1 mRNA in patients with diabetes mellitus using a competitive polymerase chain reaction (PCR) method. Renal biopsy specimens were obtained from 29 patients with non-insulin-dependent diabetes mellitus. Total RNA was extracted from the glomeruli and reverse transcribed into cDNA with reverse transcriptase. To prepare samples containing identical amounts of beta-actin cDNA (8 pg), we performed competitive PCR by co-amplifying mutant templates of beta-actin with a unique EcoRI site. We also used this competitive PCR method to measure TGF-beta 1 cDNA by co-amplifying mutant templates of TGF-beta 1. We observed higher expression of TGF-beta 1 mRNA in glomeruli of patients with diabetic nephropathy as compared with normal glomeruli. Intraglomerular TGF-beta 1 mRNA was elevated, even in the early stage of diabetic nephropathy. Moreover, levels of intraglomerular TGF-beta 1 mRNA correlated with values of HbA1c. These data suggest that hyperglycemia induces intraglomerular TGF-beta 1 mRNA expression in vivo, and that TGF-beta 1 overproduction may be associated with the progression of diabetic nephropathy.
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PMID:Quantification of glomerular TGF-beta 1 mRNA in patients with diabetes mellitus. 977 81

We have examined the regulation of endothelial IGFBP-3 production by IGF-I and TGF-beta, two growth factors thought to play a major roles in the complications of diabetes mellitus. In addition, we developed a sensitive method for IGFBP-3 mRNA quantitation by adapting the fluorescent modification of the competitive PCR strategy. Our results using both Northern analysis and the fluorescent competitive PCR method indicate that: (1) IGFBP-3 mRNA is increased 2- to 10-fold by IGF-I and maximally reduced to 20% of control by TGF-beta; (2) the changes in mRNA levels correlate with the levels of IGFBP-3 protein secreted into the media by these cells; (3) the induction of IGFBP-3 mRNA and protein by IGF-I analogs was directly related to their ability to bind to the type I IGF receptor, reflecting an IGF-I receptor-mediated process; and (4) steady state IGFBP-3 mRNA levels did not change significantly after a 6 h incubation with actinomycin D in the presence or absence of the growth factors suggesting that the observed IGF-I/TGF-beta effects occur at the level of gene transcription rather than mRNA stability.
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PMID:Regulation of endothelial IGFBP-3 synthesis and secretion by IGF-I and TGF-beta. 871 44

Impaired wound healing is a well-documented phenomenon in diabetes mellitus, yet little is known of the fundamental cause of this pathology. This study examined the effects of streptozotocin (STZ)-induced diabetes on the healing process using three wound models: (i) a linear skin incision (tensile strength), (ii) subcutaneously implanted polyvinyl alcohol sponge PVAs (collagen deposition), and (iii) stainless steel mesh chamber (TGF-beta, IGF-I and its binding proteins, extracellular matrix remodeling enzymes). RIA specific for IGF-I revealed that diabetes induced a 42% (wound fluid) and a 48% (serum) reduction in IGF-I levels. IGF-II western ligand blots found that diabetes produced a marked reduction in the level of a wound fluid 46 kDa IGF binding proteins. A proliferation-based bioassay indicates that TGF-beta level is also reduced in diabetic wound fluid (55%). Diabetes of graded metabolic severity induced by variable doses of STZ (25 mg-200 mg/kg) showed stepwise reduction in wound tensile strength and PVAs collagen deposition. In contrast, zymographic analysis of extracellular matrix proteases revealed that the diabetic wound fluid contains increased levels of 21, 69, and 72 kDa gelatinases. A single dose of TGF-beta (2 micrograms) in a collagen vehicle partially reversed the diabetes-related decrease in the tensile strength of standardized incisions. These data support the premise that wound-healing impairment in diabetes is due, at least in part, to a deficiency in growth factor activity within the wound environment.
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PMID:Transforming growth factor-beta and insulin-like growth factor-I in relation to diabetes-induced impairment of wound healing. 876 52


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