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

Fetal malformation associated with maternal diabetes occurs before the seventh week of pregnancy. Current hypotheses suggest that the diabetic milieu causes a reduction in phosphatidylinositol turnover, leading to a disruption in the arachidonic acid cascade and resulting in a deficiency of prostaglandins, particularly prostaglandin E2. This in turn results in a wide variety of congenital anomalies. This hypothesis has not been tested experimentally in humans. The yolk sac is thought to be the most important source of nutrition in early pregnancy. We sought to compare yolk sac prostaglandin levels in normal and diabetic women. Under ultrasonographic guidance, yolk sacs were aspirated form 8 normal and 12 diabetic women ranging from 8 to 10 weeks gestational age prior to elective abortion. Prostaglandin E2 levels were determined using RIA. The mean prostaglandin E2 level in normal controls was 3605 pg/mL, and was undetected in all of the yolk sacs aspirated from diabetic women (P < 0.001). Yolk sac diameter in diabetic pregnancies was 1.2 mm larger than that of normal pregnancies. The functional and morphological changes demonstrated in this study may increase our understanding of the pathophysiology of diabetic embryopathy.
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PMID:Yolk sac concentration of prostaglandin E2 in diabetic pregnancy: further clues to the etiology of diabetic embryopathy. 875 Feb 8

The arachidonic acid cascade leading to prostaglandins has been implicated in diabetic embryopathy. Both arachidonic acid and prostaglandin E2 reverse the teratogenic effects of high glucose concentrations on neural tube development in mouse embryos in culture. Arachidonic acid supplementation also protects against diabetes-induced neural tube defects in vivo. In the present study, prostaglandin E2 was measured directly in embryos from normal and diabetic mice. In normal mice a clear developmental pattern was seen. Prostaglandin E2 levels were high during early formation of the cranial neural folds (day 8), declined during convergence and fusion of the cranial neural folds to form the neural tube (day 9), and were low after neurulation was complete (days 10 and 11). In addition, evidence in this study indicates that embryos have cyclooxygenase activity capable of generating prostaglandin E2 during a brief developmental period preceding neural tube closure. In embryos from mice made diabetic (> 13.9 mmol/l glucose) with streptozotocin, prostaglandin E2 levels were significantly lower than normal during early development of the cranial neural folds (day 8), but similar to normal after the cranial neural tube had closed (late day 9 and day 10). The findings suggest that diabetes mellitus, as ascertained by high blood glucose, promotes cranial neural tube malformations by causing a functional deficiency of prostaglandin E2 during early neurulation. Whether the altered PGE2 pattern in the embryo indicates a diabetic effect on the arachidonic acid-prostaglandin cascade in cells of the embryo or in cells of extraembryonic or maternal tissues is uncertain.
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PMID:Diabetes mellitus affects prostaglandin E2 levels in mouse embryos during neurulation. 885 13

Injury of endothelial cells (EC) has been postulated as the initial trigger of the progression of atherosclerosis in patients with diabetes mellitus. We previously reported that decrease in a novel endothelium-specific growth factor, hepatocyte growth factor (HGF), by high D-glucose might be a trigger of endothelial injury. However, the physiological role of the local vascular HGF system has not yet been clarified. To investigate the role of HGF in endothelial injury, we initially examined the effects of HGF on endothelial injury induced by serum deprivation. Decrease in EC number by serum deprivation was significantly attenuated by addition of HGF as well as recombinant basic fibroblast growth factor, whereas vascular endothelial growth factor showed no effect. Apoptotic changes in EC induced by serum deprivation were also significantly attenuated by addition of HGF (p < 0.01). Given the protective action of HGF, we next studied the physiological role of local HGF production in endothelial regulation. We focused on the protective actions of prostaglandin (PG) I2, PGE and a phosphodiesterase type 3 inhibitor (cilostazol) on endothelial injury by high glucose, since these agents are widely used in the treatment of peripheral arterial disease which is frequently observed in diabetic patients. Treatment of human aortic EC with PGE1, PGE2, and a PGI2 analogue (beraprost sodium) as well as cilostazol stimulated EC growth. HGF concentration in conditioned medium from EC treated with PGE1, PGE2 or PGI2 analogue as well as cilostazol was significantly higher than that with vehicle (p < 0.01). Interestingly, treatment with PGI2 analogue or cilostazol attenuated high D-glucose-induced EC death, which was abolished by neutralizing anti-HGF antibody. Moreover, decreased local HGF production by high D-glucose was also significantly attenuated by PGI2 analogue or cilostazol. Finally, we tested the effects of PGE, PGI2 analogue and cilostazol on local HGF production in human aortic vascular smooth muscle cells (VSMC). Although high D-glucose treatment resulted in a significant increase in VSMC number, PGI2 analogue and/or cilostazol treatment had no effects on VSMC growth. However, the decrease in local HGF production by high D-glucose was significantly attenuated by addition of PGI2 analogue or cilostazol. Overall, this study demonstrated that treatment with PGE, PGI2 analogue or cilostazol prevented aortic EC death induced by high D-glucose, probably through the activation of local HGF production. Increased local vascular HGF production by prostaglandins and cilostazol may prevent endothelial injury, potentially resulting in the improvement of peripheral arterial disease.
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PMID:Role of hepatocyte growth factor in endothelial regulation: prevention of high D-glucose-induced endothelial cell death by prostaglandins and phosphodiesterase type 3 inhibitor. 930 Feb 42

Interleukin-1beta (IL-1beta) has been implicated as an effector molecule of beta-cell destruction in autoimmune diabetes. IL-1beta inhibits insulin secretion from pancreatic beta-cells by stimulating the expression of inducible nitric oxide synthase (iNOS) that generates the free radical nitric oxide. IL-1beta also induces the coexpression of the inducible isoform of cyclooxygenase (COX-2) that results in the overproduction of proinflammatory prostaglandins. The current studies were designed to characterize the involvement of protease(s) in the signaling pathway of IL-1beta-induced iNOS and COX-2 expression by rat islets and transformed rat pancreatic beta-cells. Because of the limitations of cell numbers of purified primary beta-cells obtained from rat islets, biochemical and molecular studies were performed using the rat insulinoma beta-cell line RINm5F. A serine protease inhibitor, Nalpha-P-tosyl-L-lysine chloromethyl ketone (TLCK), and a proteasome complex (26S) inhibitor, MG 132, inhibited IL-1beta-induced nitrite formation, an oxidation product of nitric oxide produced by iNOS, in a concentration-dependent manner, with complete inhibition observed at 100 micromol/l and 10 micromol/l, respectively. Both TLCK and MG 132 also inhibited iNOS gene expression at the level of mRNA and protein. In an analogous manner, TLCK (100 micromol/l) and MG 132 (10 micromol/l) inhibited IL-1beta-induced COX-2 enzyme activity (PGE2 formation) and COX-2 gene expression at the level of mRNA and protein. In human islets, the proteasome inhibitor MG 132 also inhibited the formation of the products of iNOS and COX-2 enzyme activity, nitrite, and PGE2, respectively. These findings suggest that the inhibitory action of TLCK and MG 132 on iNOS and COX-2 expression precedes transcription. The transcription factor NFkappaB is essential for activation of a number of cytokine-inducible enzymes and was evaluated as a possible site of protease action necessary for IL-1beta-induced coexpression of iNOS and COX-2. TLCK and MG 132 inhibited both IL-1beta-induced activation of NFkappaB and degradation of IkappaBalpha by islets and RINm5F cells. These results implicate protease activation as an early signaling event in IL-1beta-induced inhibition of beta-cell function. This study also suggests that IL-1beta-induced iNOS and COX-2 coexpression by pancreatic beta-cells share a common signaling pathway in utilizing the proteasome complex (26S) and the transcription factor NFkappaB, and it identifies sites of intervention to prevent the overproduction of their inflammatory products.
Diabetes 1998 Apr
PMID:Evidence for involvement of the proteasome complex (26S) and NFkappaB in IL-1beta-induced nitric oxide and prostaglandin production by rat islets and RINm5F cells. 956 91

Previous studies have suggested that the metabolism of arachidonic acid and radical oxygen species (ROS) are altered in diabetes and that these disturbances may induce severe embryonic dysmorphogenesis in diabetic pregnancy. We tested this hypothesis by studying whether an inhibition of the rate-limiting enzyme of prostaglandin biosynthesis, cyclooxygenase (COX), caused developmental disturbances analogous to those seen in embryos exposed to high glucose concentration. Whether antioxidants could prevent such developmental alterations was also investigated. Whole embryo culture was used in which day-9 embryos were exposed to high concentrations of glucose, arachidonic acid, prostaglandin (PG)E2, COX inhibitors, and antioxidants for 48 h. Increased glucose concentration (from 10 to 30 mmol/l) caused embryonic dysmorphogenesis, and addition of either 60 pmol/l arachidonic acid or 280 nmol/l PGE2 largely protected the embryo from this maldevelopment. Furthermore, exposure to the COX inhibitors indomethacin (200 micromol/l) or acetylsalicylic acid (700 micromol/l) in 10 mmol/l glucose concentration yielded embryonic dysmorphogenesis similar to that caused by 30 mmol/l glucose. Supplementation of either arachidonic acid or PGE2 to the culture medium with COX inhibitors in low glucose rectified the embryonic development, and PGE2 supplementation also normalized the development of embryos cultured with COX inhibitors in high glucose concentration. Interestingly, the antioxidants superoxide dismutase (SOD) and N-acetylcysteine (NAC) were each able to diminish the dysmorphogenesis induced by the COX inhibitors, at doses previously shown to diminish glucose-induced embryonic damage in the same in vitro culture system. In conclusion, the present study shows that a high glucose concentration disturbs embryonic development and that this disturbance may be partly mediated via altered metabolism of arachidonic acid and ROS in the embryo.
Diabetes 1998 Apr
PMID:Antioxidants diminish developmental damage induced by high glucose and cyclooxygenase inhibitors in rat embryos in vitro. 956 3

When aiming at preventing IDDM in man, knowledge of the molecular mechanisms leading to beta cell destruction may facilitate identification of new possible intervention modalities. A model of IDDM pathogenesis in man suggests that cytokines, and IL-1 in particular, are of major importance in the initial events (Nerup et al 1994) (Fig. 1). In vitro rat experiments demonstrated that rhIL-1 beta inhibits beta cell function and induces beta cell death both in isolated islets of Langerhans and in the isolated perfused pancreatic gland. With the long term goal of identifying new modalities capable of preventing IDDM in man, the aim af this review was to investigate the effects of rhIL-1 beta on beta-cell function and viability in normal rats. This review discussed 1) the pharmacokinetics of IL-1 beta in rats as the basis for choice of route of administration and dose of rhIL-1 beta, 2) the effects and molecular mechanisms of IL-1 beta on temperature and food intake used as control parameters for successful injection of rhIL-1 beta in rats, 3) the effects of one or more injection of IL-1 beta on rat beta cell function, 4) the molecular mechanisms leading to IL-1 beta induced beta cell inhibition in vivo, and some possible intervention modalities based on the molecular mechanisms, 5) the effects of IL-1 beta on spontaneous diabetes mellitus in DP BB rats, and 6) the effects and molecular mechanisms of IL-1 beta induced inhibition of thyroid epithelial cell function and aggravated thyroiditis in DP BB rats, compared to the effects of IL-1 beta on rat beta cell function. Finally, this review discussed the effects of IL-1 beta on human beta cells in vitro, and the clinical relevance of these experiments, with special reference to a clinical trial with the aim of preventing IDDM in man. The pharmacokinetic studies suggested that IL-1 beta is distributed according to a two-compartment model with a first-order elimination. Interleukin-1 beta reached all the investigated organs in the rats, was accumulated in kidneys and was excreted in the urine. The data suggested that IL-1 beta also accumulated in the islets of Langerhans. After injection of 4.0 micrograms/kg pathophysiologically relevant concentrations of rhIL-1 beta were reached and intact rhIL-1 beta persisted for up to 5 hrs in plasma. Peripheral injections of IL-1 beta dose-dependently induced fever and anorexia in rats, probably via induction of PGE2 in the brain or in peripheral tissues thereafter passing the blood-brain barrier. Nitric oxide produced by cNOS seems to be a molecular mediator of IL-1 beta induced fever but not of anorexia. Fever and anorexia are well described effects of IL-1 beta in rats, and are as such usefull control parameters of the absorption and biological activity of IL-1 beta after peripheral injection. Injections of rhIL-1 beta to normal, non-diabetes prone rats induced initial beta cell stimulation followed by inhibition, in accordance with in vitro data. Furthermore, induction of peripheral insulin resistance coincided with beta cell inhibition after one daily injection for 5 days, leading to a transient diabetes mellitus-like state, characterized by hyperglycemia and hypoinsulinemia. At this time point, electron-microscopy did not demonstrate beta cell destruction. However, IL-1 beta induced intercellularly edema and microvillous processes on the beta cells, which might be early evidence of apoptosis. The diabetes mellitus-like state was not aggravated if the daily injections were continued beyond 5 days. Daily injections of rhIL-1 beta for 2 to 4 weeks induced formation of blocking IL-1 beta-antibodies in normal rats. Hence, injections exceeding 2 weeks should only be performed using species homologous IL-1 beta. The molecular mechanism of IL-1 beta induced beta cell inhibition in rats in vivo as in vitro, are likely to involve binding of IL-1 beta to the IL-1RtI, since the IL-1RtII is considered to be a decoy receptor. (ABSTRACT TRUNCATED)
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PMID:Interleukin-1 beta induced transient diabetes mellitus in rats. A model of the initial events in the pathogenesis of insulin-dependent diabetes mellitus? 958 1

Type I diabetes appears to be a T cell dependent disease. T cell reactivity is regulated by antigen presenting cells (APCs). In animal models of type I diabetes, abnormal reactivity of APCs, in particular of macrophages, probably is responsible for the progression of islet inflammation from T helper type 2 dependent benign periinsulitis to T helper type I dependent destructive intrainsulitis. The functional state of APCs during preferential stimulation of Th1 reactivities (APC1 state) is characterized by the release of TNFalpha, IL-12 and/or IL-18. The bias towards APC1 reactivity has been found due to defective inhibition via IL-10 and PGE2.
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PMID:The APC1 concept of type I diabetes. 960 35

The interaction of cells with the surrounding extracellular matrix (ECM) or basement membrane (BM) brings about profound changes in cellular biological responses, such as cell differentiation, proliferation, and gene expression. We studied the effect of ECM on PTH receptor binding and on biological responses mediated by PTH, in two cell preparations: 1) the proximal tubular OK opossum kidney cell line; and 2) MC3T3-E1 cells, a clonal line of nontransformed murine osteoblasts. Cells were plated on either plastic surfaces or on tissue culture dishes coated with specific ECM components. In both cell types plated on collagen-type IV (Col-IV), PTH receptor binding, on day 4 of culture, was markedly diminished, when compared with cells on plastic (approximately 45% inhibition, P < 0.01). In addition, Col-IV dose dependently inhibited cAMP generation stimulated by PTH (P < 0.001 vs. plastic), whereas cAMP generation by PGE2, cholera toxin, and forskolin was not altered. In Northern blot analysis, a PTH/PTH-related-protein receptor messenger RNA transcript was detected in both the kidney and bone cells. However, only OK cells manifested a decreased abundance of receptor messenger RNA when plated on Col-IV, compared with plastic. The physiological significance of inhibited cAMP production by Col-IV was evaluated by measuring the influence of different matrices on the activity of Na+/H+ exchanger (NHE) in OK cells and cell mitogenic activity in MC3T3-E1 cells (both responses are negatively modulated by cAMP). OK cells plated on Col-IV showed 70% inhibition of NHE, compared with cells plated on plastic (P < 0.01). PTH inhibits NHE activity in cells on plastic but stimulates exchanger activity by 40% in cells plated on Col-IV. In MC3T3-E1 cells grown on plastic, PTH exerts a dose-dependent antiproliferative effect, which is mediated by cAMP. This effect is mitigated when cells are grown on Col-IV (40-50% less antiproliferative effect). In summary, Col-IV, a maj or BM constituent, has a profound inhibitory effect on PTH binding and PTH-mediated biological responses in both kidney tubular cells and osteoblasts. Altered cellular function by Col-IV may be of physiological relevance in states associated with altered composition of BM or expansion of ECM (e.g. diabetes mellitus and interstitial fibrosis).
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PMID:The effect of cell-matrix interaction on parathyroid hormone (PTH) receptor binding and PTH responsiveness in proximal renal tubular cells and osteoblast-like cells. 964 78

Oxidation of lipoproteins, and, in particular, low-density lipoproteins (LDL), has been shown to play a significant role in the pathogenesis of atherosclerosis. Oxidized LDL are endocytosed via scavenger receptors to form lipid-laden foam cells. The non-enzymatic reaction of glucose with proteins and lipoproteins results in a modified LDL involved in the pathogenesis of late complications in diabetes mellitus. In the present paper, the influence of various E-series prostaglandins (PGE1; 13,14-dihydro PGE1; 13,14-dihydro 15-keto PGE1; and PGE2) on oxidation of native and glycated LDL was investigated. The effect of these agents in the concentration range from 1 pg/mL to 1.6 micrograms/mL on copper-induced oxidation of native and glycated LDL was tested. The concentration of each agent causing the maximal effect on oxidation of native LDL, as measured by the formation of thiobarbituric acid-reacting substances, was chosen to estimate the effect on 2, 4, 8, and 24 h oxidation of glycated LDL. The study was performed with LDL isolated by sequential ultracentrifugation from normolipidemic individuals. LDL (0.25 mg protein/mL) was oxidatively modified with 5 microM CuSO4. The glycosylation of LDL was performed by incubation of LDL with 500 mM glucose for varying periods of time ranging from 10 to 31 days. Our results show that only 13,14-dihydro PGE1 significantly inhibits copper-induced oxidation of native LDL, while the other examined E-series prostaglandins in vitro are ineffective as reducing agents in LDL-oxidation.
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PMID:Do E-series prostaglandins and their metabolites influence oxidation of native and glycated low-density lipoproteins? 966 Dec 19

Diabetes mellitus is a systemic disease that affects more than 12 million people in the United States and represents a risk factor for periodontitis with odds ratios of 2.1 to 3.0. New data support the concept that in diabetes-associated periodontitis, the altered host inflammatory response plays a critical role. We have recently examined the gingival crevicular fluid (GCF) mediator level, monocytic secretion, and clinical presentation of 39 insulin-dependent diabetes mellitus (IDDM) patients and 64 non-diabetic patients with various degrees of periodontal health and disease. First, we found that there was an unexpected high level of GCF mediators among the IDDM subjects, even in the gingivitis and mild periodontitis patients. Furthermore, the GCF and monocytic mediator responses were obviously bimodal in distribution with respect to periodontal status. Gingivitis patients and mild periodontitis patients represented one low response group, and the moderate and severe periodontitis subjects the high response group. Accordingly, these 4 periodontal subgroups were pooled to form 2 main groups for analyses--group A (AAP Types I-II) and group B (AAP Types III-IV). Diabetics had significantly higher GCF levels of both PGE2 and IL-1 beta when compared to non-diabetic controls with similar periodontal status. Within the diabetic group, the GCF levels of these inflammatory mediators were almost 2-fold higher in group B subjects when compared to diabetics from group A. Among diabetics, GCF TNF-alpha levels were only marginally detectable and no significant difference was found between group A and group B patients. Insulin-dependent diabetic patients with gingivitis or mild periodontitis (group A) and moderate to severe periodontitis (group B) have abnormal monocytic inflammatory secretion in response to LPS challenge from Porphyromonas gingivalis (P. gingivalis) as compared to non-diabetic periodontal patients. Data suggest that the diabetic state results in a significantly upregulated monocytic secretion of PGE2 (4.2-fold), IL-1 beta (4.4-fold), and TNF-alpha (4.6-fold) when compared to non-diabetic controls. Within diabetics, LPS dose-response curves demonstrated that monocytes from group B patients secreted approximately 3 times more PGE2 and 6.2 times more TNF-alpha than those from group A; however, there was no significant difference in monocytic IL-1 beta secretion between the 2 diabetic groups. This upregulated monocytic trait is thought to exist independently of the presence of severe periodontal disease since, in non-diabetic patients with adult periodontitis, Gram-negative bacterial infections alone are not sufficient to elicit a systemic hyperresponsive monocytic trait. Between group A and group B diabetics, there was no significant difference in metabolic control as expressed by mean level of glycosylated hemoglobin (HbA1c). In conclusion, our data suggest that diabetic patients have exaggerated inflammatory responses when compared to non-diabetic controls. Furthermore, within diabetics, individuals with moderate to severe periodontitis (group B) have significantly elevated monocytic secretion of PGE2 and TNF-alpha upon LPS challenge and significantly higher GCF levels of PGE2 and IL-1 beta when compared to patients with gingivitis or mild periodontal disease (group A). Thus, we suggest that insulin-dependent diabetes mellitus is a significant risk factor for more severe periodontal disease because, as compared to non-diabetics, diabetic subjects react with an abnormally high degree of inflammation to an equivalent bacterial burden.
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PMID:PGE2, IL-1 beta, and TNF-alpha responses in diabetics as modifiers of periodontal disease expression. 972 89


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