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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Renal disease is one of the most common and severe complications of diabetes mellitus. The hallmark of the disease, glomerulosclerosis, is characterized by an accumulation of extracellular matrix in the mesangial areas, leading to progressive obliteration of the vascular spaces. The role of the metabolic derangements of diabetes mellitus in the development of these lesions is incompletely understood. One of the consequences of hyperglycemia is the formation of advanced glycosylation end products (AGEs), which result from a series of rearrangements secondary to nonenzymatic reaction of glucose with proteins. Specific receptors for proteins modified by AGEs, present in several cell types, were recently described in human and rat mesangial cells. Furthermore, exposure of mesangial cells to AGEs was followed by an increase in fibronectin production. In the present study we show evidence that mouse mesangial cells exhibit an increase in collagen type IV mRNA and peptide synthesis after exposure to AGEs. Antibodies to AGE receptors prevent this increase, indicating that the response is AGE-receptor-mediated. In addition, anti-platelet-derived growth factor abrogates the AGE response, suggesting that platelet-derived growth factor acts as an intermediate factor. Transcription assay reveals that the elevated mRNA levels are due to an increase in the transcription rate, rather than to an increase in the stability of the message. Finally, the mRNAs coding for laminin and heparan sulfate proteoglycan are also increased after exposure to AGE, whereas glyceraldehyde 3-phosphate dehydrogenase mRNA levels remain constant. The increase in extracellular matrix mRNAs seen in the current study suggests that AGE formation in vivo may be one of the metabolic events leading to the development of diabetic glomerulosclerosis.
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PMID:Receptor-specific increase in extracellular matrix production in mouse mesangial cells by advanced glycosylation end products is mediated via platelet-derived growth factor. 131 71

The roles of growth factors in the pathogenesis of various forms of acute and chronic renal disease are largely putative. Nevertheless, there is a growing body of information that links specific growth factors to particular forms of renal injury. In all instances, it is supposed that such associations are not necessarily unique and that multiple cytokines probably interact to determine the pattern of injury or the regenerative response to such injury. Regeneration of tubular epithelium after acute tubular necrosis involves upregulation of the epidermal growth factor (EGF) receptor. Early studies of exogenously administered EGF indicate that the severity and duration of renal failure may be attenuated by this growth factor. Thus far, the observed responses have been limited and the role of EGF as a therapeutic agent requires more study. The mechanism of generation of tubulointerstitial injury in most forms of renal disease is difficult to understand. Early in vitro studies of growth factor production by tubular cells (in the absence of any infiltrating cells) indicate that platelet-derived growth factor produced by the medullary collecting duct is mitogenic for renal medullary fibroblasts, suggesting a paracrine growth system in this region of the kidney. Insulin-like growth factor I has also been shown to be produced by collecting duct cells. Its production is increased by EGF, and its association with certain forms of renal hypertrophy, i.e., diabetes and hypersomatotrophic states, implies its participation in the hypertrophic growth response. Platelet-derived growth factor is a potent mitogen for glomerular mesangial cells, and its production is regulated by a variety of cytokines.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evolving role of growth factors in the renal response to acute and chronic disease. 159 57

Although platelet-derived growth factor (PDGF) is thought to be a major mediator of atherosclerotic disease, the pathophysiology of diabetic vasculopathy, including atherosclerosis, is unclear. By means of an enzyme immunoassay that used a monoclonal antibody against human PDGF-B chain, PDGF-like immunoreactivity was determined in serum, platelet-poor plasma, and platelet lysate of 28 patients with non-insulin-dependent diabetes mellitus and 11 control subjects. Growth-promoting activity was also measured by tritiated thymidine incorporation into DNA of cultured human fibroblasts. The PDGF-like immunoreactivity in serum was correlated (r = 0.42; p less than 0.01) with that in platelet lysate prepared from a fixed volume of blood. Furthermore, a correlation (r = 0.70; p less than 0.001) was found between the PDGF-like immunoreactivity and the growth-promoting activity in platelet lysate but not in serum. There was no significant difference between patients with diabetes and control subjects with respect to the PDGF-like immunoreactivity in serum or in platelet lysate (38.2 +/- 2.2 vs 42.8 +/- 3.1 ng/ml or 49.1 +/- 2.4 vs 56.2 +/- 3.4 ng/mg protein; mean +/- SEM). In contrast, the serum growth-promoting activity was lower (p less than 0.05) in patients with diabetes than in control subjects (88.1% +/- 7.1% vs 117.4% +/- 6.9%) and there was a negative correlation (r = -0.39; p less than 0.05) between the serum growth-promoting activity and the fasting plasma glucose level. The growth-promoting activity in platelet lysate of patients with diabetes did not differ from that of the control subjects (59.9% +/- 11.6% vs 65.9% +/- 11.2%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Platelet-derived growth factor and growth-promoting activity in the serum samples and platelets of patients with non-insulin-dependent diabetes mellitus. 161 32

This study used 10-nm gold particles with 5-7 insulin molecules attached (Au10-Ins) to investigate the site of interaction of insulin with the nuclear envelope during insulin uptake into intact isolated nuclei. Despite its size, and in the absence of ATP, Au10-Ins entered nuclei through the nuclear pore and associated with the heterochromatin. Because Au10-Ins is essentially gold-bovine serum albumin (Au-BSA) with a few insulin molecules attached, the effect of insulin and other growth factors on the nuclear accumulation of BSA coupled to 10-, 15-, and 24-nm-diam colloidal gold particles (Au10-BSA, Au15-BSA, and Au24-BSA) was determined. The Au-BSA complexes were excluded from nuclei in the absence of insulin. Insulin (0.5-100 ng/ml) caused a dose-dependent accumulation of Au10-BSA in the nucleus. The nuclear membrane was shown to be intact by several criteria, therefore, accumulation of Au-BSA occurred via the nuclear pore and was not due to leakage across or through the membrane. Uptake of 15- and 24-nm Au-BSA molecules was not affected by insulin, suggesting the hormone had a limited effect in increasing the functional diameter of the nuclear pores. Glucagon, epidermal growth factor, platelet-derived growth factor, insulinlike growth factor I, and insulin A or B chains did not stimulate the accumulation of Au10-BSA. The insulin-stimulated accumulation of Au10-BSA was blocked by concanavalin A, mimicked by wheat-germ agglutinin, and did not require ATP. The Au10-BSA in the nucleus was associated with heterochromatin, suggesting it bound to a nuclear element.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetes 1992 Feb
PMID:Insulin stimulates accumulation and efflux of macromolecules in isolated nuclei from H35 hepatoma cells. 173 9

We review some key aspects of the maturation of stimulus-secretion coupling and the regulation of DNA replication in the fetal beta-cell. During fetal life, the beta-cell shows a poor insulin response to glucose, although it responds to several other nonnutrient stimuli. However, chronic exposure to glucose in excess of basal levels can induce maturation of the stimulus-secretion coupling. Studies of glucose metabolism and the transmembrane flow of K+ and Ca2+ indicate that the attenuated glucose-stimulated insulin release is due to an immature glucose metabolism resulting in impaired regulation of ATP-sensitive K+ channels in the plasma membrane of the fetal beta-cell. In late fetal life, glucose is also a strong stimulus to beta-cell replication, and metabolism of glucose is a prerequisite for this process. Glucose stimulates proliferation by recruiting beta-cells from a resting state into a proliferative compartment composed of cells in an active cell cycle. The proliferative compartment comprises less than 10% of the total islet cell population even at maximal stimulation. The proliferation of fetal beta-cells is also regulated by several peptide growth factors such as growth hormone, insulinlike growth factor I, and platelet-derived growth factor. The observation that glucose can both induce precocious maturation of the stimulus-secretion coupling and stimulate proliferation of the fetal beta-cell explains the intrauterine hyperinsulinemia and beta-cell hyperplasia of the offspring of diabetic mothers with relatively mild hyperglycemia. However, severe hyperglycemia, at least when induced in rats, seems to retard rather than stimulate beta-cell growth.
Diabetes 1991 Dec
PMID:Functional maturation and proliferation of fetal pancreatic beta-cells. 174 74

Epidermal and platelet-derived growth factors are potent mitogens for many types of cells, including smooth muscle cells. Epidermal growth factor in blood of humans is present both in platelets (as reflected in its serum level) and in plasma, the source(s) of which remains unknown. We assayed its level in 82 diabetic patients and 53 age-matched controls. In diabetes, epidermal growth factor level was increased in serum (191 +/- 43 vs 155 +/- 64 pmol/l, p = 0.0002) and plasma (53 +/- 9 vs 38 +/- 14 pmol/l, p less than 0.0001), without any difference between the patients with and without complications. Platelet-derived growth factor level was assayed only in serum of 19 patients with uncomplicated diabetes and found elevated (222 +/- 47) as compared with 13 controls (160 +/- 26 pmol/l), (p = 0.0002). Type of diabetes, its duration, mode of therapy, control, presence of retinopathy or albuminuria (in case of epidermal growth factor), as well as C-peptide age and sex did not correlate with epidermal or platelet-derived growth factor levels. Serum but not plasma epidermal and platelet-derived growth factor were negatively correlated with serum creatinine (correspondingly, r = -0.373, p = 0.0008 and r = -0.564, p = 0.0285). It is concluded that diabetes itself and not its complications cause increased levels of epidermal growth factor in plasma and serum and of platelet-derived growth factor in serum.
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PMID:Epidermal growth factor and platelet-derived growth factor in blood in diabetes mellitus. 223 81

Diabetes and aging are commonly accompanied by arterio- and atherosclerosis. Infiltration of the arterial subendothelial intima by macrophages/monocytes is an important early event preceding the development of atheromatous lesions; these macrophages are known to produce mitogenic factors in early atherosclerotic lesions. It has been previously shown that, over time, vascular matrix accumulates proteins nonenzymatically modified by advanced glycosylation end products (AGEs). In view of the fact that macrophages/monocytes have AGE-specific receptors associated with the expression of several growth factors, we investigated the possibility that AGEs mediate initial monocyte-vessel wall interactions that occur before overt formation of vascular lesions. This study demonstrates that (i) in vitro- and in vivo-formed AGEs are chemotactic for human blood monocytes, (ii) sub-endothelial AGEs can selectively induce monocyte migration across an intact endothelial cell monolayer, and (iii) subsequent monocyte interaction with AGE-containing matrix results in the expression of platelet-derived growth factor. These results support the existing hypothesis that in vivo-forming glucose-derived protein adducts can act as signals for the normal turnover of senescent tissue protein by means of the AGE-specific receptor system. Time-dependent glucose-induced deposition of AGEs on matrix proteins may promote monocyte infiltration into the subendothelium. Subsequent AGE-triggered macrophage activation and consequent elaboration of proliferative factors may normally coordinate remodeling but may also lead to the diverse pathogenic changes typical of arterio- and atherosclerosis in diabetic or aging populations.
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PMID:Advanced protein glycosylation induces transendothelial human monocyte chemotaxis and secretion of platelet-derived growth factor: role in vascular disease of diabetes and aging. 224 77

Restenosis after percutaneous transluminal coronary angioplasty (PTCA) probably results from pathophysiological mechanisms that are initiated during PTCA. Platelet deposition or exposed subendothelial connective tissue initiates complex blood element and vessel wall interactions that are not completely understood and leads to a proliferative response at the site of injury. The incidence of restenosis is also related to clinical, anatomic, and procedural variables. An increased frequency of restenosis is seen in patients who have recent onset of angina, unstable angina, or vasospastic angina, and in those who have diabetes. Stenoses in the proximal left anterior descending coronary artery, the ostium of the right coronary artery, and the proximal portion of a bypass vein graft have higher rates of restenosis than lesions at other sites. Restenosis can be predicted by an incomplete PTCA, which is identified by a high residual pressure gradient across the stenosis. Mechanical and pharmacological methods of preventing restenosis are under investigation. Intravascular stenting with expandable metal sleeves and laser angioplasty have shown encouraging results. Longer balloon inflation time can help prevent early elastic recoil. Platelet inhibitors (e.g., aspirin, dipyridamole, and sulfinpyrazone) do not appear to have an effect on restenosis. Agents, however, that interfere with platelet deposition at the PTCA site and that modify the effect of platelet-derived growth factor and medial cell proliferation show promise for control of restenosis.
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PMID:Restenosis after percutaneous transluminal coronary angioplasty--anatomic and pathophysiological mechanisms. Strategies for prevention. 240 72

Insulin is a potent mitogen for many cell types in vitro. During tissue culture, supraphysiological concentrations of insulin are necessary to promote cell replication in connective or musculoskeletal tissues. Insulin promotes the growth of these cells by binding, with low affinity, to the type I insulin-like growth factor (IGF) receptor, not through the high affinity insulin receptor. In other cell types, such as hepatocytes, embryonal carcinoma cells, or mammary tumor cells, the type I IGF receptor is virtually absent, and insulin stimulates the growth of these cells at physiological concentrations by binding to the high affinity insulin receptor. Both receptor systems activate phosphorylation reactions within the cell which extend to ribosomal proteins. Insulin acts synergistically with other factors, such as platelet-derived growth factor and epidermal growth factor, to stimulate the progression of cells through the cycle of proliferation. Abnormal insulin secretion or action, before or after birth, often is associated with disordered growth suggesting that insulin may function as a growth factor in vivo. Poor growth follows impaired insulin secretion in diabetes mellitus. This is associated with reduced circulating levels of IGF's which may be partly responsible for the growth failure. Insulin has a direct action on release of IGF's from the liver in vitro, but during experimental diabetes there is a reduced number of hepatic somatotropic receptors which could limit the ability of growth hormone to regulate IGF release. Diabetic children, treated conventionally, have normal circulating IGF levels, but both growth rate and serum IGF concentration may increase dramatically when diabetic control is optimized.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Insulin as a growth factor. 241 20

Diabetes mellitus is associated with premature senescence of cultured dermal fibroblasts. The present study investigated the effect of elevated glucose concentrations on cultured human fibroblasts from normal donors. Mean population doubling times, population doublings until senescence, saturation density at confluence (cells/cm2), tritiated thymidine incorporation, and response to platelet-derived growth factor (PDGF) were inhibited with the increasing glucose concentrations (11.0, 22, 44, or 55 mM glucose) (P less than 0.05). Replicative life span was markedly diminished by multiple passages in high glucose medium (5.5 mM glucose: 62.4 +/- 7.9 population doublings; 22 mM glucose: 22.8 +/- 3.4 population doublings: P less than 0.05). Aldose reductase activity was present in the cultured fibroblasts (3.9 +/- 0.5 nmol/min per mg protein), and inhibitors of aldose reductase, including sorbinil (10(-4) M--10(-6) M) and tolrestat (10(-6) M--10(-8) M), completely prevented glucose-mediated inhibition of fibroblast proliferation, restored the response to PDGF, and allowed a normal replicative life span. Myo-inositol (11 microM--5.5 mM) also reversed the adverse effects of glucose. These in vitro data demonstrate that elevated concentrations of glucose inhibit cell growth and promote premature senescence, effects which can be prevented with inhibitors of aldose reductase or supplemental myo-inositol. These aldose reductase-related effects may explain the impaired growth and premature senescence of cultured connective tissue from diabetic patients.
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PMID:Glucose inhibition of human fibroblast proliferation and response to growth factors is prevented by inhibitors of aldose reductase. 249 84


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