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

Insulin resistance is associated not only with the classic cardiovascular risk factors of hypertension and dyslipidemia, but also with several disorders of coagulation and fibrinolysis. Elevated concentrations of the fibrinolytic inhibitor plasminogen activator inhibitor-1 are associated with insulin resistance. In experimental systems, increased expression and secretion of plasminogen activator inhibitor-1 by hepatocyte and endothelial cell lines can be induced by insulin, proinsulin-like molecules, triglyceride-rich lipoproteins and oxidized LDL, as well as by inducing insulin resistance in isolated hepatocytes. Concentrations of the endothelial cell protein von Willebrand factor are elevated in insulin-resistant states, suggesting that abnormalities of capillary endothelium, as well as those reported for endothelium-dependent vasodilatation, may play a role in the etiology of insulin resistance. Levels of a third coagulation factor, fibrinogen, are elevated in insulin-resistant subjects, an association that suggests a possible role for acute-phase cytokines in the abnormalities of coagulation and endothelial function. It is proposed that the recent observations of secretion of interleukin-6 by adipose tissue, combined with the actions of adipose tissue-expressed tumor necrosis factor-alpha in obesity-induced insulin resistance, could underlie the associations of insulin resistance with endothelial dysfunction, coagulopathy, and coronary heart disease.
Diabetes Care 1999 Apr
PMID:Abnormalities of coagulation and fibrinolysis in insulin resistance. Evidence for a common antecedent? 1018 59

Women with diabetes mellitus have an increased risk of developing coronary heart disease which may be related at least partially to unfavourable changes in haemostasis. The effect of oestrogen replacement therapy on haemostasis has not been studied systematically in women with non-insulin-dependent diabetes mellitus (NIDDM) and therefore this study was performed for that purpose. Twenty-five postmenopausal women with NIDDM were treated with 2 mg of 17-beta-oestradiol orally for 3 months in a double-blind, crossover, placebo-controlled trial. During the last 16 days of active treatment, 1 mg of norethisterone acetate was added for 10 days for endometrial protection. Blood samples were taken at baseline and after 68 days of active or placebo treatment. Treatment with oestradiol was followed by a marked decrease in the activity of plasminogen activator inhibitor, compared with placebo. The activity of tissue plasminogen activator increased significantly. Levels of antithrombin decreased during treatment with oestradiol, whereas no changes were seen in levels of fibrinogen, von Willebrand factor, prothrombin fragment 1+2, protein S, protein C or resistance to activated protein C. In conclusion, oestrogen replacement therapy in postmenopausal women with NIDDM improved the fibrinolytic activity, while only clinically insignificant alterations in the clotting system were seen. These changes in haemostasis may have a favourable impact on the risk for coronary heart disease in diabetic women.
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PMID:The effects of oestrogen replacement therapy on haemostatic variables in postmenopausal women with non-insulin-dependent diabetes mellitus. 1019 56

It is unknown whether and to what extent changes in various endothelial functions and adrenergic responsiveness are related to the development of microvascular complications in type 1 diabetes. Therefore, endothelium-dependent and endothelium-independent vasodilatation, endothelium-dependent hemostatic factors, and one and two adrenergic vasoconstrictor responses were determined in type 1 patients with and without microvascular complications. A total of 34 patients with type 1 diabetes were studied under euglycemic conditions on two occasions (11 without microangiopathy, 10 with proliferative and preproliferative retinopathy previously treated by laser coagulation, 13 with microalbuminuria, and 12 healthy volunteers also were studied). Forearm vascular responses to brachial artery infusions of N(G)-monomethyl-L-arginine (L-NMMA), sodium nitroprusside, acetylcholine (ACh), clonidine, and phenylephrine were determined. The ACh infusions were repeated during coinfusion of L-arginine. Furthermore, plasminogen activator inhibitor type 1 (PAI-1) activity, tissue plasminogen activator antigen levels, von Willebrand factor antigen levels, tissue factor pathway inhibitor (TFPI) activity, and endothelin-1 levels were measured. No differences in endothelium-dependent or endothelium-independent vasodilatation or adrenergic constriction were observed between the diabetic patients and the healthy volunteers. In comparison to the first ACh infusion, the maximal response to repeated ACh during L-arginine administration was reduced in the diabetic patients, except in the patients with proliferative and preproliferative retinopathy previously treated by laser coagulation. In these patients, the combined infusion of L-arginine and ACh resulted in an enhanced response. TFPI activity was elevated, and PAI-1 activity was reduced in the type 1 diabetic patients. Furthermore, PAI-1 activity was positively correlated with urinary albumin excretion (r = 0.48, P < 0.01) and inversely correlated with the vasodilatory response to the highest ACh dose (r = -0.37, P < 0.05). The response to the highest ACh and L-NMMA dose were positively correlated with mean arterial blood pressure (r = 0.32, P < 0.01; r = 0.41, P < 0.01, respectively). Forearm endothelium-dependent and endothelium-independent vasodilatation and adrenergic responsiveness were unaltered in type 1 diabetic patients with and without microvascular complications. Relative to healthy control subjects, endothelium-dependent vasodilatation was depressed during a repeated ACh challenge (with L-arginine coinfusion) in the diabetic patients without complications or with microalbuminuria. In contrast, this vasodilatation was enhanced in the patients with retinopathy. Elevation of TFPI was the most consistent marker of endothelial damage of all the endothelial markers measured.
Diabetes 1999 Jun
PMID:Endothelium-dependent vasodilatation, plasma markers of endothelial function, and adrenergic vasoconstrictor responses in type 1 diabetes under near-normoglycemic conditions. 1034 20

The relationship between haematological factors and peripheral arterial disease (PAD) among diabetics has not been widely examined. 1592 men and women aged 55-74 years were selected from the general population. They underwent an assessment for PAD and a glucose tolerance test. 288 subjects (18.7%) were identified as having diabetes or impaired glucose tolerance (IGT). Among the diabetes/IGT group, median levels of fibrinogen, von Willebrand factor (VWF), tissue plasminogen activator (t-PA), fibrin D-dimer and plasma viscosity were higher in subjects with PAD than those without PAD (P </= 0.05). The prevalence of PAD was higher in those with diabetes/IGT (20.6%) compared to those with normal glucose tolerance (12.5%) (odds ratio 1.64; 95% CI 1.17, 2.31). After separate adjustment for fibrinogen, VWF, t-PA, fibrin D-dimer, leucocyte elastase, plasma viscosity and haematocrit, those with diabetes/IGT no longer had a significantly higher risk of PAD compared to those with a normal glucose tolerance test. Simultaneous adjustment for the first four of these haematological factors reduced the risk of PAD among subjects with diabetes/IGT to 1.11 (95% CI 0.76, 1.63). Increased levels of haemostatic factors may partly explain the higher prevalence of PAD in diabetic/IGT subjects compared to normal glucose-tolerant subjects. Future randomized controlled trials involving the indirect lowering of levels of haematological factors should help to explain whether the associations reported here are of causal significance.
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PMID:The role of haematological factors in diabetic peripheral arterial disease: the Edinburgh artery study. 1035 25

A slightly elevated urinary albumin excretion rate (UAER), above 5-10 microgram/min, is a predictor of atherosclerotic cardiovascular disease. Endothelial dysfunction is an important early feature of atherosclerosis. The plasma concentration of von Willebrand factor (vWF), a potential marker of endothelial dysfunction, predicts a subsequent increase of UAER in patients with diabetes. The aim of this study is to test the hypothesis that high concentrations of vWF as well as other haemostatic factors predict progression of UAER in clinically healthy subjects. UAER was measured together with selected markers of haemostatic function-vWF, tissue plasminogen activator (tPA), plasminogen activator inhibitor, factor VII and fibrinogen-in healthy volunteers aged 40-65 years. After a mean follow-up of 4.1 years, 64 of 74 agreed to a re-examination including re-measurement of UAER. Baseline vWF and tPA were both positively correlated to the change in UAER during follow-up (r=0.26, P=0.04 and r=0.40, P=0.001 respectively). The mean UAER increased significantly by 7.6 microgram/min and 7.5 microgram/min respectively in subjects with vWF and tPA above the medians at baseline (P=0.01 and P=0.003 respectively), whereas no changes in UAER were seen in subjects with vWF and tPA below the medians. Subjects with high tPA were also characterized by an excess of other cardiovascular risk factors at baseline. No significant differences in these risk factors were present between subjects with high or low vWF. High plasma concentrations of vWF and tPA are associated with progression of UAER in clinically healthy subjects. Both vWF and tPA are secreted by endothelial cells and the results suggest that endothelial dysfunction leads to progression of UAER.
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PMID:Endothelial haemostatic factors are associated with progression of urinary albumin excretion in clinically healthy subjects: a 4-year prospective study. 1036 4

Before de novo synthesized von Willebrand factor (vWF) leaves the endothelial cell, it undergoes endoproteolytic cleavage of its propeptide (vW antigen II). The processed vWF and propeptide are either released constitutively or, following activation of the endothelium, released through the regulated pathway. In a recent study (Borchiellini et al, Blood 88:2951, 1996), we showed that the half-life of mature vWF and of its propeptide differ fourfold to fivefold. We postulated that the molar ratio of the propeptide to mature vWF could serve as a tool to assess the extent of endothelial cell activation under physiologic and clinical conditions. To test this hypothesis, we measured mature vWF and propeptide in patients with documented acute and chronic vascular disease, including patients with thrombotic thrombocytopenic purpura (TTP), acute septicemia, and diabetes mellitus. These data were compared with experimental conditions in healthy subjects in which perturbation of the endothelium was simulated by physical exercise or by administration of 1-deamino-8-D-arginine vasopressin (DDAVP) or endotoxin. In all individuals of the latter study group, both vWF and propeptide levels were elevated during the acute phase of the experimentally induced vascular perturbation; at later time points after stimulation, only vWF levels remained elevated. In patients with sepsis and TTP, both vWF and propeptide were elevated several-fold. Thus, this pattern can readily be explained in terms of acute perturbation of the endothelium. In contrast, in patients with diabetes mellitus propeptide levels were only slightly elevated, whereas vWF levels were elevated twofold to threefold. This pattern is a typical feature of chronic, low-grade activation of the endothelium. These observations support our hypothesis that measurement of both propeptide and vWF levels allows to discriminate between chronic and acute phases of endothelial cell activation in vivo. Measurement of only vWF is less indicative in this respect.
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PMID:von Willebrand factor propeptide in vascular disorders: A tool to distinguish between acute and chronic endothelial cell perturbation. 1038 11

Of the threats to health and life that beset the person with diabetes, cardiovascular disease (CVD), particularly coronary heart disease (CHD) but also cerebrovascular and peripheral vascular disease, represent the heaviest burden. The relative risk for CVD is very high for Type 1 diabetes, but the absolute risk, in terms of numbers, is much higher for Type 2. In all societies, diabetes increases cardiovascular risk twofold or more, compared with the local non-diabetic population. Some of the evidence for this diabetes-related increase in cardiovascular risk is reviewed and its relationship to recognised cardiovascular risk factors considered. The explanation of the enhanced susceptibility to atherosclerotic disease in diabetes remains a matter of contention. How much can be explained by greater prevalence in diabetes of such risk factors as hypertension and dyslipidaemia? To what extent is the impact of a given level of risk factor magnified by a co-existing diabetic state? Is the increased cardiovascular morbidity and mortality secondary to risk factors specifically related to the diabetic state itself? Does the explanation lie in altered coagulability due to changes in platelet activation and aggregability, fibrinogen levels, Factor VII, von Willebrand factor or PAI-1, in the concentration or composition of plasma lipoproteins, in defective endothelial cell function or other metabolic abnormalities of the arterial wall? To what extent is cardiovascular risk related to the degree of hyperglycaemia, protein glycation, relative hyperinsulinaemia and insulin resistance? Data from recent epidemiological, intervention and laboratory investigations bearing on causation, management and prevention of CVD in diabetes are reviewed. Evidence for the impact of correction of glycaemia, dyslipidaemia and raised arterial pressure is considered and reasons are adduced for a broad and proactive therapeutic approach with early identification and vigorous correction of key risk factors.
Diabetes Metab Res Rev
PMID:Reducing the burden of diabetes: managing cardiovascular disease. 1044 Oct 41

Diabetes mellitus is associated with a marked increase in the risk of coronary events but with an altered circadian distribution that demonstrates an absent morning peak and higher infarction rate during the evening hours. To elucidate the mechanism of this phenomenon, the circadian pattern of heart rate variability was evaluated in 22 type I diabetic patients with diabetic autonomic neuropathy in conjunction with circadian changes of fibrinolytic and hemostatic factors. The circadian pattern (6 A.M. to 10 P.M. vs 10 P.M. to 6 A.M.) of 3 indexes of parasympathetic tone was evaluated using 24-hour heart rate variability analysis. The high-frequency power (3.0 +/- 0.2 vs 3.3 +/- 0.2 ms2, p = 0.08) and the percentage of RR intervals with >50 ms variation (0.47 +/- 0.18 vs 0.69 +/- 0.33 ms, p = 0.52) demonstrated no significant circadian variation. The square root of mean squared differences of successive RR intervals showed a small but significant increase during nighttime (8.5 +/- 0.7 vs 9.7 +/- 1.1 ms, p = 0.02). Fibrinolytic activity was significantly lower at 8 A.M. than at 4 P.M. (166.4 +/- 12.5 to 200.2 +/- 9.3 mm2, p = 0.0003), but with a low amplitude. Plasminogen activator inhibitor 1 showed no circadian variation. Factor VII and fibrinogen demonstrated a significant reduction from 8 A.M. to 4 P.M., but both peak and nadir values were elevated. The von Willebrand factor was markedly elevated with no circadian variation. Thus, diabetic autonomic neuropathy is associated with a loss of both the nocturnal predominance of parasympathetic activity and a prothrombotic state that persists throughout the day. These abnormalities may attenuate the relative protection from coronary events during the afternoon and nighttime.
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PMID:Circadian patterns of heart rate variability, fibrinolytic activity, and hemostatic factors in type I diabetes mellitus with cardiac autonomic neuropathy. 1046 85

There is a microcirculation system within the islets of Langerhans. However, little is known about the phenotypic and functional characterization of islet microvascular endothelial cells (MVEC). In this study, we purified MVEC from human pancreatic islets by using Ulex europaeus (Sigma, St. Louis, MO) agglutinin-1 (UEA-1)-coated dynabeads (Dynal A.S., Oslo, Norway). These purified human islet MVEC (HI-MVEC) express von Willebrand factor, take up high levels of acetylated LDL, and upregulate endothelial cell leukocyte adhesion molecule 1 in response to tumor necrosis factor-alpha. Ultrastructure examination shows the presence of microvilli and fenestrations on the cell surface, Weibel-Palade bodies in the cytoplasm, and tight junctions between cells. Furthermore, we show that vascular endothelial cell growth factor contributes to the formation of surface fenestrations on cultured HI-MVEC. After purification, HI-MVEC exhibit a very low proliferation capacity and are strongly resistant to trypsin, compared with other original MVEC. We also demonstrate that alpha-1 proteinase inhibitor (Api) is expressed on HI-MVEC and specifically located at the area of cell-cell junctions. By reverse transcription-polymerase chain reaction, a significant messenger RNA band of Api was found only in HI-MVEC, but not in other organ-derived MVEC, indicating that expression of Api is islet MVEC specific. Antibodies to Api significantly reversed the resistance to trypsin and promoted proliferation of HI-MVEC, suggesting that these specific functional characteristics of HI-MVEC are related to the expression of Api. These results indicate that HI-MVEC exhibit some specific morphological and functional characteristics that differ from MVEC derived from other organs.
Diabetes 1999 Sep
PMID:Expression of alpha-1 proteinase inhibitor in human islet microvascular endothelial cells. 1048 Jun 7

Abnormalities in vascular reactivity in the micro- and macrocirculation are well established in type 2 diabetes. However, little is known about changes in vascular reactivity in those at risk for developing type 2 diabetes. To address this situation, the vascular reactivity in both the micro- and macrocirculation was studied in four age and sex comparable groups: 30 healthy normoglycemic subjects with no history of type 2 diabetes in a first-degree relative (controls), 39 healthy normoglycemic subjects with a history of type 2 diabetes in one or both parents (relatives), 32 subjects with impaired glucose tolerance (IGT), and 42 patients with type 2 diabetes without vascular complications (diabetes). Laser Doppler perfusion imaging was used to measure vasodilation in the forearm skin in response to iontophoresis of 1% acetylcholine chloride (Ach) (endothelium-dependent) and 1% sodium nitroprusside (SNP) (endothelium-independent), whereas high-resolution ultrasound images were used to measure brachial artery diameter changes during reactive hyperemia. Plasma concentrations of endothelin-1 (ET-1), von Willebrand factor (vWF), soluble intercellular adhesion molecule (sICAM), and soluble vascular cell adhesion molecule (sVCAM) were also measured as indicators of endothelial cell activation. The vasodilatory responses to Ach, expressed as percent increase of blood flow over baseline, were reduced in relatives (98 +/- 48, mean +/- SD), IGT (94 +/- 52), and diabetes (74 +/- 45) compared with controls (126 +/- 67) (P < 0.001 controls versus relatives, IGT, and diabetes). The responses to SNP were similarly reduced: controls (123 +/- 46), relatives (85 +/- 46), IGT (83 +/- 48), and diabetes (65 +/- 31) (P < 0.001 controls versus relatives, IGT, and diabetes) as were the responses in the brachial artery diameter during reactive hyperemia: controls (13.7 +/- 6.1), relatives (10.5 +/- 6.7), IGT (9.8 +/- 4.5), and diabetes (8.4 +/- 5.0) (P < 0.01 controls versus relatives, IGT, and diabetes). Women had greater responses than men in both the micro- and macrovascular circulatory tests, but a similar progressive reduction was observed in both sexes with increasing degrees of glucose intolerance. A significant inverse correlation was found between microvascular reactivity and systolic blood pressure, fasting plasma glucose, HDL cholesterol, fasting plasma insulin, and homeostasis model assessment (HOMA) values, an index of insulin resistance. BMI and diastolic blood pressure had a significant inverse correlation only with endothelium-dependent vasodilation. In the macrocirculation, systolic blood pressure, HbA1c, HDL cholesterol, and HOMA had significant correlation with brachial artery diameter changes. Compared with control subjects, ET-1 was significantly higher in all groups, vWF was higher only in the diabetic group, sICAM levels were higher in the IGT and diabetic groups, while sVCAM concentrations were higher in the relatives and those with diabetes (P < 0.05). On stepwise multivariate analysis, age, sex, fasting plasma glucose, and BMI were the most important contributing factors to the variation of vascular reactivity. Addition of all clinical and biochemical measures explained only 32-37% of the variation in vascular reactivity. These results suggest that abnormalities in vascular reactivity and biochemical markers of endothelial cell activation are present early in individuals at risk of developing type 2 diabetes, even at a stage when normal glucose tolerance exists, and that factors in addition to insulin resistance may be operative.
Diabetes 1999 Sep
PMID:Microvascular and macrovascular reactivity is reduced in subjects at risk for type 2 diabetes. 1048 Jun 19


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