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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Blood levels of the clotting factor fibrinogen and tissue plasminogen activator inhibitor-1 (PAI-1), a primary inhibitor of fibrinolysis, have been positively linked to risk of coronary heart disease. The authors have reported previously that plasma fibrinogen appears to rise after menopause and to be reduced with use of postmenopausal hormonal therapy. There is also evidence to suggest that sex hormones may influence PAI-1. To examine whether plasma fibrinogen and PAI-1 antigen levels differ among older postmenopausal women according to use of hormone therapy and by blood level of estrogen and androgens, these variables were assessed among 277 healthy women aged 65-82 years, one half of whom were receiving therapy. The study population was drawn from the Study of Osteoporotic Fractures, Pittsburgh, Pennsylvania, during 1986-1988. Overall, results showed median PAI-1 levels to be lower on average with oral and transdermal use of hormone therapy (25.0 vs. 33.5 ng/ml, p < 0.01) and mean fibrinogen levels to be lower (279 vs. 295 mg/dl, p < 0.02) with use of oral estrogen (but not transdermal) therapy compared with women not receiving therapy. Among women not receiving therapy, PAI-1 and fibrinogen levels were not related to endogenous sex hormone levels, with the exception of a modest positive relation between PAI-1 and serum estrone concentrations (rs = 0.29). In addition, a markedly higher PAI-1 level was found for women with a preponderance of upper body fat, independent of obesity. In sum, results showed that older women receiving postmenopausal hormone therapy had more favorable plasma levels of the hemostatic factors PAI-1 and fibrinogen than did those not receiving therapy, which can be explained in large part by differences between the two groups in obesity and body fat distribution.
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PMID:Association of sex hormones and adiposity with plasma levels of fibrinogen and PAI-1 in postmenopausal women. 854 17

Plasminogen activator inhibitor-1 (PAI-1) is related to insulin resistance and several components of the insulin resistance syndrome, and PAI-1 levels are elevated in subjects with non-insulin-dependent diabetes mellitus. Many Pima Indians are obese, insulin-resistant, and hyperinsulinemic, and they have high rates of diabetes but a low risk of ischemic heart disease. In contrast to whites and Asians, PAI-1 activity is similar between nondiabetic and diabetic Pima Indians. We therefore examined the association of PAI-1 with hepatic and peripheral insulin action measured using the hyperinsulinemic-euglycemic clamp. To investigate if insulin per se has any effect on PAI-1 in vivo, we also assessed the effects of endogenous (during a 75-g oral glucose load) and exogenous (during hyperinsulinemic clamp) insulin on PAI-1 antigen. Twenty-one (14 men and seven women; mean age, 26.3 +/- 4.8 years) Pima Indians underwent a 75-g oral glucose tolerance test (OGTT) and a sequential hyperinsulinemic-euglycemic clamp. Peripheral insulin action was measured as absolute glucose uptake (M value) and normalized to estimated metabolic body size (EMBS). Hepatic insulin action was measured as percent suppression of basal hepatic glucose output during hyperinsulinemia. PAI-1 antigen was determined using a two-site enzyme-linked immunosorbent assay that detects only free PAI-1. PAI-1 antigen concentrations were significantly related to body mass index ([BMI] rs = .54, P = .012), waist (rs=.52, P=.016) and thigh (rs=.63, P=.002) circumference, and fasting plasma insulin concentration (rs=.59, P=.004). PAI-1 antigen concentrations were not significantly associated with peripheral glucose uptake (M value) during either low-dose (rs= -.01, P=NS) or high-dose (rs= -.11, P=NS) insulin infusion. PAI-1 antigen was negatively correlated with basal hepatic glucose output (rs= -.57, P=.013) and percent suppression of hepatic glucose output during hyperinsulinemia (rs= -.69, P=.005). However, this relationship was largely due to the confounding effects of BMI, waist and thigh girth, fasting insulin, and 2-hour postload glucose concentrations, and was not significant when controlled for these variables (partial rs= -.30, P=NS). There was no significant relationship of PAI-1 antigen concentration with glucose storage or glucose oxidation. Despite a threefold increase in plasma insulin concentrations during the OGTT, there were no significant changes in PAI-1 antigen concentrations (median, 57, 61, 55, and 44 ng/mL at 0, 60, 120, and 180 minutes, respectively; P=NS by ANOVA). During the hyperinsulinemic clamp, mean plasma insulin concentrations at the end of low-dose (240 pmol/m2/min) and high-dose (2,400 pmol/m2/min) infusions were 1,005 and 14,230 pmol/L, respectively. However, PAI-1 antigen concentrations at the end of low-dose and high-dose insulin infusions were similar to those at baseline (median, 63, 43, and 58 ng/mL, respectively; P=NS by ANOVA). PAI-1 antigen in Pima Indians is related to several components of the insulin resistance syndrome. However, direct measurement of insulin resistance indicates that hepatic but not peripheral insulin resistance is related to PAI-1 antigen. Neither endogenous nor exogenous hyperinsulinemia for short periods had any significant effect on PAI-1 antigen concentrations. Short-term hyperinsulinemia is unlikely to be an important regulator of PAI-1 in Pima Indians. The relationship of PAI-1 antigen to hepatic insulin resistance is largely dependent on the relationship of PAI-1 to indices of obesity and fasting insulin concentrations.
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PMID:Relationship of hepatic and peripheral insulin resistance with plasminogen activator inhibitor-1 in Pima Indians. 884 79

Plasminogen activator inhibitor-1 is elevated in obesity and may be a risk factor for obesity/NIDDM related cardiovascular disease. In spite of this, little is known about the tissue and cellular origin of elevated PAI-1 in obesity or of the mediators and molecular mechanisms that regulate it. We have begun to systematically address these issues using genetically obese (ob/ob, db/db) mice. Plasma PAI-1 levels were 5-fold higher in obese mice compared to their lean counterparts. Subsequent RT-PCR and in situ hybridization studies suggest that the increased plasma PAI-1 originates primarily from the adipocyte in response to chronically elevated levels of tumor necrosis factor-alpha (TNF-alpha), insulin, and transforming growth factor-beta (TGF-beta). Thus, the signals and mechanisms that lead to elevated plasma PAI-1 observed in obesity are complex, and appear to involve interactions between multiple mediators and the adipose tissue itself.
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PMID:The fat mouse: a powerful genetic model to study elevated plasminogen activator inhibitor 1 in obesity/NIDDM. 919 33

One of the most robust observations in the biology of aging is that caloric restriction (CR) extends life in a variety of species. Although CR results in a severalfold decrease in fat mass (FM), the role of fat on life extension was considered to be minimal. Two main reasons accounted for this belief. First, although increased FM is associated with changes in substrate oxidation and in glucose homeostasis, in part through the effects of free fatty acids (FFA) and glycerol, several studies have suggested that longevity is determined independent of FM. Second, CR has systemic effects on a range of functions including neurological, endocrine, reproductive, immunological and antineoplastic, none of which have been historically linked to fat. In the last few years, an explosion of evidence has demonstrated that fat tissue is a very active endocrine gland which secretes a variety of peptides (such as leptin and plasminogen activating inhibitor-1), cytokines (such as tumor necrosis factor), and complement factors (such as D, C3, and B). This is in addition to the presence of substrates, such as glycerol and FFA, which are stored and released by fat cells and are known to have a major role in hepatic and peripheral glucose metabolism. We propose that many of the systemic effects of CR can now be explained by the chronic effects related to decreased plasma levels of peptides, cytokines, complement factors, and substrates. In fact, all of the benefits of CR on the neuroendocrine system and those related to the improvement in glucose homeostasis can be attributed to decrease in adipose cells and their products. Other evidence from epidemiological data in human obesity supports the role of fat mass and its body distribution as a risk factor for morbidity and mortality in humans due to impaired glucose metabolism (similar to rodents), for cancer (similar to rodents), and for the development of atherosclerotic vascular disease (in humans). If all or most of the life-extending benefits of CR can be attributed to decreased fat stores, the expression of specific candidate proteins may be explored and manipulated in the search for the most powerful adipose-dependent signals that modulate life expectancy.
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PMID:Revisiting the role of fat mass in the life extension induced by caloric restriction. 1019 31

The known metabolic cardiovascular disease risk factors associated with insulin resistance syndrome (IRS) do not adequately explain the excess cardiovascular disease risk attributed to this syndrome, and abnormalities in hemostatic variables may contribute to this excess risk. Using data from 322 nondiabetic elderly men and women (aged 65-100 years) participating in the Cardiovascular Health Study during 1989-1990, the authors performed factor analysis on 10 metabolic risk factors associated with IRS and 11 procoagulation, inflammation, and fibrinolysis variables to examine the clustering of the metabolic and hemostatic risk markers. Factor analysis of the metabolic variables confirmed four uncorrelated factors: body mass, insulin/glucose, lipids, and blood pressure. Adding the hemostatic variables yielded three new factors interpreted as inflammation, vitamin K-dependent proteins, and procoagulant activity. Plasminogen activator inhibitor-1 clustered with the body mass factor, supporting the hypothesis that obesity is related to impaired fibrinolysis. Fibrinogen clustered with the inflammation summary factor rather than procoagulant activity, supporting the position that fibrinogen principally reflects underlying inflammation rather than procoagulant potential. The authors conclude that should hemostatic variables be shown to contribute to IRS-related cardiovascular disease, apart from plasminogen activator inhibitor-1, they may do so independently of the established metabolic abnormalities.
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PMID:Clustering of procoagulation, inflammation, and fibrinolysis variables with metabolic factors in insulin resistance syndrome. 1128

The present study represents a new insight into the Biguanides and the Prevention of the Risk of Obesity (BIGPRO) 1 study population at inclusion. This population, selected basically on the basis of a high waist-to-hip ratio (>/=0.95 for men and >/=0.80 for women), is supposed to represent a group of patients with insulin resistance. The present study was undergone to establish whether apolipoprotein C-III (apoC-III) and apolipoprotein E (apoE) associated with apo B (apoC-III LpB and apoE LpB, respectively), considered to be markers of remnant accumulation, play a role in the hypertriglyceridemia associated with insulin resistance and whether they are related to other biological abnormalities frequently observed in this syndrome. In this population, the concentration of the markers of remnant accumulation increases with triglyceride levels. Therefore, correlation studies were realized to assess the relative effect of insulin and the markers of remnant accumulation on triglyceride plasma level. As a first attempt, a simple correlation analysis revealed that insulin is positively related to the markers of remnant accumulation only in hypertriglyceridemic patients (triglycerides >/=1.7 mmol/L). To assess the independent contribution of these markers, insulin, and other parameters related to the plasma triglyceride concentration, a stepwise multiple regression analysis was run. Results revealed that insulin and the markers of remnant accumulation (specifically, apoE LpB) are independent contributors to the plasma triglyceride concentration. Markers of the endothelial damage, plasminogen activator inhibitor-1, tissue plasminogen activator, and von Willebrand factor, which are often increased in the case of insulin resistance, were tested for their correlation with the markers of remnant accumulation. Plasminogen activator inhibitor-1 is positively correlated with these markers only in hypertriglyceridemic male subjects. It is concluded that increased insulin levels found in insulin resistance syndrome are associated with an increased production of triglyceride-rich lipoproteins enriched in apoC-III and apoE. The accumulation of these remnants and/or their abnormal composition in apoC-III and apoE could be an explanation for the development of hypertriglyceridemia in this syndrome.
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PMID:Accumulation of triglyceride-rich lipoprotein in subjects with abdominal obesity: the biguanides and the prevention of the risk of obesity (BIGPRO) 1 study. 1123 21

Human adipose tissue has an important protein secretory function. Cytokines, hormones, prohormones and enzymes are secreted from fat cells and act in an endocrine or paracrine fashion. The production of several of these proteins is affected by obesity; normally there is an increase in the obese state. Protein production is, as a metabolic activity, subject to regional variations. In particular, the production of leptin, angiotensinogen, interleukin-6 and plasmin activator inhibitor-1 differs between subcutaneous and visceral adipose tissue sites, but no regional differences have been reported in the production of tumour necrosis factor alpha. It is possible that regional variations in protein production by adipose tissue are of importance in some of the endocrine and metabolic disturbances seen in various forms of obesity, such as visceral and upper-body obesity.
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PMID:Regional differences in protein production by human adipose tissue. 1135 30

Low fibrinolytic activity may increase the risk of thrombosis. Plasminogen activator inhibitor-1 (PAI-1) is an inhibitor of the fibrinolytic system. We examined the PAI-1 levels in patients with ischemic stroke. Plasma levels of PAI-1 were measured using enzyme-linked immunosorbent assay (ELISA) in 55 consecutive patients (age 60.2 +/- 11.4, 40 males and 15 females) with ischemic stroke. The PAI-1 assessments as well as neurological examinations using validated stroke scales were conducted at admission and 1 week, 1 month, and 3 months after stroke. Sex- and age-matched controls (+/- 4 years) underwent plasma PAI-1 measurement once. Etiology of the stroke was classified using the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. All pertinent stroke risk factors were recorded. All patients were contacted 3 years after stroke for recurrent vascular thrombotic disease. The plasma PAI-1 levels were 17.2 +/- 7.8 IU at admission, 11.2 +/- 9.2 IU at 1 week, 14.4 +/- 7.9 IU at 1 month, and 17.8 +/- 7.8 IU at 3 months among patients and 11.8 +/- 9.5 IU among controls (p values are < .002, .7, .12, and < .0005, respectively). As a rule, the neurological scores did not show a correlation to the PAI-1 levels. Presence of diabetes, hypertension, obesity, smoking, anticoagulant treatment, and sleep apnea did not affect the PAI-1 levels at any time point. Females had slightly higher PAI-1 levels. Age was a strong determinant for PAI-1 levels being higher in younger patients at every sampling time point (p values .02, .02, .02, and .03 respectively). The etiology of the ischemic stroke did not have an impact on PAI-1 levels. In 16 patients recurrent thrombosis had occurred. The high PAI-1 levels at admittance may reflect either an acute phase response or a chronic state. Normalized levels at 1 week and 1 month may be due to hospital diet, antithrombotic medication, weight loss, active physical therapy, and better care for diabetes. PAI-1 levels at 3 months after stroke did not predict recurrent thrombosis.
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PMID:Plasminogen activator inhibitor-1 in patients with ischemic stroke. 1145 24

Adipokines such as Plasminogen activator inhibitor-1 (PAI-1), interleukin (IL)-8, and tumor necrosis factor (TNF)-alpha are elevated in patients with obesity, insulin resistance, and type 2 diabetes. In the present study, we investigated whether glucose affected the production of these adipokines in human adipose tissue in vitro. Glucose (up to 35mM) increased secretion of PAI-1 (p<0.01) and IL-8 (p<0.01), but not TNF-alpha, in a dose- and time-dependent manner. Half-maximal stimulatory concentration of glucose was about 1mM. Glucosamine (5mM) decreased production of PAI-1 (p<0.05) and IL-8 (p<0.05), indicating that the hexosamine biosynthesis pathway is not involved in the glucose-induced increment in adipokine secretion. The present data demonstrate that glucose increases PAI-1 and IL-8 secretion. However, glucose concentrations above 5mM had no additional effects on adipokine secretion, suggesting that mechanisms other than diabetes/insulin resistance-related hyperglycemia may be involved in the observed elevation of these adipokines.
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PMID:Stimulation of PAI-1 and adipokines by glucose in human adipose tissue in vitro. 1455 Feb 86

Plasminogen activator inhibitor-1 (PAI-1) levels were found to be associated with obesity indicating that adipocytes influence PAI-1 plasma levels. In addition, the 4 G/5 G promoter polymorphism of the PAI-1 gene may modulate PAI-1 transcription. We investigated the transcriptional regulation of the human PAI-1 gene in adipocytes and analyzed the genetic contribution of the 4 G/5 G polymorphism. The PAI-1 promoter was analyzed using electrophoretic mobility shift assays (EMSAs) and luciferase reporter gene assays. A putative binding site for the upstream stimulatory factor-1/2 (USF-1/2) at the polymorphic region of the PAI-1 promoter was identified. The binding of USF-1/2 was studied using nuclear extracts prepared from adipocytes and was similar in all the promoter variants as analyzed by EMSA. A 257 bp PAI-1 promoter fragment including the 4 G/5 G site was transcriptionally active in adipocytes and was not influenced by the polymorphism. The present data indicate for the first time that USF-1/2 is transcriptionally active in differentiated adipocytes. However, USF-1/2 binding activity and PAI-1 transcription are not influenced by the 4 G/5 G-allele. These data possibly explain the observation that PAI-1 secretion from adipose tissue is not influenced by the PAI-1 promoter polymorphism.
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PMID:Plasminogen activator inhibitor-1 promoter activity in adipocytes is not influenced by the 4 G/5 G promoter polymorphism and is regulated by a USF-1/2 binding site immediately preceding the polymorphic region. 1476 99


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