Differences in plasminogen activator inhibitor 1 in subcutaneous versus omental adipose tissue in non-obese and obese subjects

Chronotype and Sleep Quality in Obesity: How Do They Change After Menopause?

PURPOSE OF REVIEW

This review primarily provides an overview of the current evidence on chronotype (which reflects an individual's preference for the timing of sleeping, eating, and activity in a 24-h period) and sleep quality changes in obesity in postmenopausal women. It also explores possible nutritional strategies to manage these changes in this phase of a woman's life.

RECENT FINDINGS

Menopause is a life stage frequently associated with sleep disturbances and changes in circadian rhythms. Sleep disturbances are one of the main symptoms of menopause and are caused by several factors such as hormonal changes, obesity, and melatonin reduction. In addition, the chronotype also changes following menopause. Nutritional strategies are essential because they could help manage menopausal sleep disturbances and circadian misalignment, particularly by tackling obesity and overweight. In the management of postmenopausal women, especially those experiencing obesity, careful assessment of sleep disturbances and chronotype and subsequent development of the most appropriate treatment, including nutritional management, should be part of the treatment routine.

Different body parts' fat mass and corrected QT interval on the electrocardiogram: The Fasa PERSIAN Cohort Study

Background

Previous studies suggested that obesity and fat mass are associated with QT interval prolongation, but the role of different body parts' fat mass is unclear. The associations between total and regional fat mass (FM) and corrected QT interval (QTc) were investigated for the first time in this study.

Methods

In this sub-analysis of Fasa PERSIAN cohort Study data, 3217 subjects aged 35–70 entered our study. Body fat mass was assessed by bioelectrical impedance analysis and QTc interval calculated by the QT interval measured by Cardiax^® software from ECGs and Bazett’s formula. Uni- and multi-variable linear and logistic regression was performed in IBM SPSS Statistics v23.

Results

In males, the fat mass to fat-free mass (FM/FFM) ratio in the trunk, arms, total body, and legs were significantly higher in the prolonged QTc group (QTc > 450 ms). Trunk (B = 0.148), total (B = 0.137), arms (B = 0.124), legs (B = 0.107) fat mass index (FMI) showed significant positive relationship with continuous QTc (P-value < 0.001). Also, just the fat-free mass index of legs had significant positive associations with QTc interval (P-value < 0.05). Surprisingly, in females, the mean of FM/FFM ratio in trunk and legs in the normal QTc group had higher values than the prolonged QTc group (QTc > 470 ms). Also, none of the body composition variables had a significant correlation with continuous QTc.

Conclusion

Our study suggested that FMI ratios in the trunk, total body, arms, and legs were positively associated with QTc interval in males, respectively, from a higher to a lower beta-coefficient. Such associations were not seen in females. Our study implies that body fat mass may be an independent risk factor for higher QTc interval and, consequently, more cardiovascular events that should be investigated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02095-2.

A practical nutritional guide for the management of sleep disturbances in menopause

Sleep disturbances (SD) represent one of the main symptoms of menopause and they are caused by several factors. Hormonal changes such as the reduction of oestrogen levels and the consequent vasomotor symptoms (VMS) along with psychiatric disorders such as depression and anxiety could contribute to the onset of SD. Furthermore, obesity per sè or through the obstructive sleep apnoea (OSA) could blunt sleep. Moreover, in menopause is usual a reduction in melatonin, that could contribute to SD. Nutritional strategies are paramount because they could contribute to manage menopause-related SD, in particular tackling obesity and overweight. Furthermore, some foods, such as soy, fish, whole grains, vegetables and fruit could decrease symptoms like depression and VMS, correlated with SD in postmenopausal women. Therefore, the aim of this review is to provide an overview of the current evidence on SD in menopause and to provide nutritional strategies for managing SD in this context.

Immunohistochemical expression of plasminogen activator inhibitor-1 in subcutaneous versus omental adipose tissue in patients after elective abdominal surgery

Plasminogen activator inhibitor-1 (PAI-1) is a biomarker of thrombosis. Adipose and vascular tissues are among the major sources of PAI-1 production. Previous studies indicated that fat deposits mediate increased cardiovascular risk among obese individuals. We investigated the immunohistochemical (IHC) expression of PAI-1 in adipose and vascular tissues from the omentum and the subcutaneous tissue. The pathology samples were selected from 37 random patients who underwent elective abdominal surgery between 2008-2009. PAI-1 expression was semi-quantitatively scored and compared between the groups. Significant differences were noted in the IHC expression of PAI-1 between the omental and the subcutaneous adipose tissues (1.1 ± 0.8 versus 0.8 ± 0.6, respectively (p=0.05)). Adipose tissue displayed higher IHC expression of PAI-1 compared to vascular wall tissue in both omentum and subcutaneous sections (1.1 ± 0.8 versus 0.5 ± 0.9 (p=0.004), and 0.8 ± 0.6 versus 0.4 ± 0.6 (p=0.003), respectively). In conclusion, our study compared PAI-1 expression in the omentum versus the subcutaneous tissue and adipose versus vascular tissues. IHC expression of PAI-1 level was significantly higher in the omental adipose tissue compared to the subcutaneous adipose tissue. Adipose tissue displayed significantly higher PAI-1 expression than vascular tissue. The study elucidates the biological differences of adipose and vascular tissue from subcutaneous versus omental sections.

Breast Lipofilling Does Not Pose Evidence of Chronic Inflammation in Rats

BACKGROUND

Laboratory reports on adipose tissue suggest that fat grafting to the breast may pose an oncologic risk. One possible reason for this is the theoretic chronic inflammation due to adipokynes released by grafted white adipose tissue (WAT).

OBJECTIVES

The aim of this study was to analyze inflammatory activity in lipofilled breast through the use of proinflammatory markers.

METHODS

Fifty-four paired-breasts of female rats were divided into 4 groups: control, sham, and breasts grafted with either autologous subcutaneous (SC) WAT or autologous omentum (OM). The WAT was prepared through centrifugation, and the grafting was performed with the use of 0.9-mm blunt-tip cannula. The rats were killed 8 weeks postoperatively, and their breasts were harvested for immunohistochemical staining for CD68-expressing macrophages, gene expression (real-time PCR) for monocyte chemoattractant protein 1 (MCP-1), F4/80, Cox-2, and IL-6.

RESULTS

The weights of the rats that underwent a procedure differed from those of the unmanipulated control group (P < 0.01). The macrophage counts of CD68 differed only between breasts lipofilled with OM and control (P < 0.01). MCP-1, F4/80, and Cox-2 were similarly expressed among the groups (P = 0.422, P = 0.143, and P = 0.209, respectively). The expression of IL-6 differed between breast samples grafted with SC and OM WAT (P = 0.015), but not between samples of control and OM (P = 0.752), and control and SC (P = 0.056).

CONCLUSIONS

No inflammation activity was identified in the microenvironment of lipofilled breasts, indicating that chronic inflammation does not seem to be triggered by the breast lipofilling procedure.

Plasminogen Activator Inhibitor-1 is Regulated Through Dietary Fat Intake and Heritability: Studies in Twins

In different pathophysiological conditions plasminogen activator inhibitor-1 (PAI-1) plasma concentrations are elevated. As dietary patterns are considered to influence PAI-1 concentration, we aimed to determine active PAI-1 plasma concentrations and mRNA expression in adipose tissue before and after consumption of a high-fat diet (HFD) and the impact of additive genetic effects herein in humans. For 6 weeks, 46 healthy, non-obese pairs of twins (aged 18–70) received a normal nutritionally balanced diet (ND) followed by an isocaloric HFD for 6 weeks. Active PAI-1 plasma levels and PAI-1 mRNA expression in subcutaneous adipose tissue were assessed after the ND and after 1 and 6 weeks of HFD. Active PAI-1 plasma concentrations and PAI-1 mRNA expression in adipose tissue were significantly increased after both 1 and 6 weeks of HFD when compared to concentrations determined after ND (p< .05), with increases of active PAI-1 being independent of gender, age, or changes of BMI and intrahepatic fat content, respectively. However, analysis of covariance suggests that serum insulin concentration significantly affected the increase of active PAI-1 plasma concentrations. Furthermore, the increase of active PAI-1 plasma concentrations after 6 weeks of HFD was highly heritable (47%). In contrast, changes in PAI-1 mRNA expression in fatty tissue in response to HFD showed no heritability and were independent of all tested covariates. In summary, our data suggest that even an isocaloric exchange of macronutrients — for example, a switch to a fat-rich diet — affects PAI-1 concentrations in humans and that this is highly heritable.

Plasminogen activator inhibitor links obesity and thrombotic cerebrovascular diseases: The roles of PAI-1 and obesity on stroke

One of the global socioeconomic phenomena occurred during the last decades is the increased prevalence of obesity, with direct consequence on the risk of developing thrombotic disorders. As the physiological inhibitor of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA), plasminogen activator inhibitor-1 (PAI-1) is well known for its role in fibrinolysis. More and more evidences have shown that PAI-1 involves in physiopathologic mechanisms of many diseases and metabolic disorder. Increased serum level of PAI-1 has been observed in obesity and it also contributes to the development of adipose tissue and then has effects on obesity. Meantime, obesity affects also the PAI-1 levels. These evidences indicate the complicated interaction between PAI-1 and obesity. Many clinic studies have confirmed that obesity relates to the stroke outcome although there are many contradictory results. Simultaneously, correlation is found between plasma PAI-1 and thrombotic cerebrovascular diseases. This article reviews contemporary knowledge regarding the complex interplay of obesity, PAI-1 and stroke.

Obesity and Its Potential Effects on Antidepressant Treatment Outcomes in Patients with Depressive Disorders: A Literature Review

Accumulating evidence regarding clinical, neurobiological, genetic, and environmental factors suggests a bidirectional link between obesity and depressive disorders. Although a few studies have investigated the link between obesity/excess body weight and the response to antidepressants in depressive disorders, the effect of weight on treatment response remains poorly understood. In this review, we summarized recent data regarding the relationship between the response to antidepressants and obesity/excess body weight in clinical studies of patients with depressive disorders. Although several studies indicated an association between obesity/excess body weight and poor antidepressant responses, it is difficult to draw definitive conclusions due to the variability of subject composition and methodological differences among studies. Especially, differences in sex, age and menopausal status, depressive symptom subtypes, and antidepressants administered may have caused inconsistencies in the results among studies. The relationship between obesity/excess body weight and antidepressant responses should be investigated further in high-powered studies addressing the differential effects on subject characteristics and treatment. Moreover, future research should focus on the roles of mediating factors, such as inflammatory markers and neurocognitive performance, which may alter the antidepressant treatment outcome in patients with comorbid obesity and depressive disorder.

Body fat, especially visceral fat, is associated with electrocardiographic measures of sympathetic activation

OBJECTIVE

Obesity is associated with sympathetic activation, but the role of different fat depots is unclear. The association between body fat, specifically visceral fat, and electrocardiographic measures of sympathetic activation in a population with structurally normal hearts was investigated.

METHODS

In this cross-sectional baseline analysis of the Netherlands Epidemiology of Obesity study, body fat percentage was assessed with BIA and abdominal subcutaneous (SAT) and visceral adipose tissue (VAT) with magnetic resonance (MR) imaging. Mean heart rate (HR) and five other electrocardiographic measures of sympathetic activation were calculated. We performed multivariate linear regression analyses.

RESULTS

In 868 participants with a mean age(SD) of 55(6) years, BMI of 26(4) kg/m(2) , 47% men, body fat was associated with HR and two other measures of sympathetic activation. Per sex-specific SD total body fat, the difference in HR was 1.9 beats/min (95% CI: 1.0, 2.9; P < 0.001) and per SD waist circumference 2.1 beats/min (95% CI: 1.3, 2.9; P < 0.001). The difference in HR per SD VAT was 2.1 beats/min (95% CI: 1.3, 3.0; P < 0.001).

CONCLUSIONS

Body fat, especially visceral fat, was associated with electrocardiographic measures of sympathetic activation. Our study implies that already before the onset of cardiovascular disease, excess (visceral) body fat is associated with sympathetic activation.

Combined ethanol extract of grape pomace and omija fruit ameliorates adipogenesis, hepatic steatosis, and inflammation in diet-induced obese mice

The aim of this study was to evaluate the long-term effects of grape pomace ethanol extract (GPE) with or without omija fruit ethanol extract (OFE) on adiposity, hepatic steatosis, and inflammation in diet-induced obese mice. Male C57BL/6J mice were fed a high-fat diet (HFD) as the control diet and HFD plus GPE (0.5%, w/w) with or without OFE (0.05%, w/w) as the experimental diet for 12 weeks. GPE alone did not significantly affect adipogenesis and hepatic steatosis. However, the supplementation of GPE + OFE significantly lowered body weight gain, white adipose tissue weight, adipocyte size, and plasma free fatty acid and adipokines (leptin, PAI-1, IL-6, and MCP-1) levels in HFD-fed mice compared to those of the control group. These beneficial effects of GPE + OFE were partly related to the decreased expression of lipogenic and inflammatory genes in white adipose tissue. GPE + OFE supplementation also significantly lowered liver weight and ameliorated fatty liver by inhibiting expression of hepatic genes involved in fatty acid and cholesterol syntheses as well as inflammation and by activating hepatic fatty acid oxidation. These findings suggest that the combined ethanol extract of grape pomace and omija fruit has the potential to improve adiposity and fatty liver in diet-induced obese mice.

Pathophysiology of human visceral obesity: an update

Excess intra-abdominal adipose tissue accumulation, often termed visceral obesity, is part of a phenotype including dysfunctional subcutaneous adipose tissue expansion and ectopic triglyceride storage closely related to clustering cardiometabolic risk factors. Hypertriglyceridemia; increased free fatty acid availability; adipose tissue release of proinflammatory cytokines; liver insulin resistance and inflammation; increased liver VLDL synthesis and secretion; reduced clearance of triglyceride-rich lipoproteins; presence of small, dense LDL particles; and reduced HDL cholesterol levels are among the many metabolic alterations closely related to this condition. Age, gender, genetics, and ethnicity are broad etiological factors contributing to variation in visceral adipose tissue accumulation. Specific mechanisms responsible for proportionally increased visceral fat storage when facing positive energy balance and weight gain may involve sex hormones, local cortisol production in abdominal adipose tissues, endocannabinoids, growth hormone, and dietary fructose. Physiological characteristics of abdominal adipose tissues such as adipocyte size and number, lipolytic responsiveness, lipid storage capacity, and inflammatory cytokine production are significant correlates and even possible determinants of the increased cardiometabolic risk associated with visceral obesity. Thiazolidinediones, estrogen replacement in postmenopausal women, and testosterone replacement in androgen-deficient men have been shown to favorably modulate body fat distribution and cardiometabolic risk to various degrees. However, some of these therapies must now be considered in the context of their serious side effects. Lifestyle interventions leading to weight loss generally induce preferential mobilization of visceral fat. In clinical practice, measuring waist circumference in addition to the body mass index could be helpful for the identification and management of a subgroup of overweight or obese patients at high cardiometabolic risk.

Conditioned media from (pre)adipocytes stimulate fibrinogen and PAI-1 production by HepG2 hepatoma cells

Background:

Obesity is associated with a prothrombotic state, which may contribute to the increased risk of thrombotic events.

Objective:

To assess the effects of (pre)adipocyte-derived adipokines on fibrinogen, plasminogen activator inhibitor-1 (PAI-1) and tissue factor (TF) production by hepatocytes.

Methods:

HepG2 hepatocytes were incubated with conditioned media (CM) derived from preadipocytes and adipocytes, which had been untreated or prestimulated with tumor necrosis factor (TNF)-α, interleukin (IL)-1β or IL-6. After 24 h, supernatants and cell lysates were harvested for measurement of fibrinogen, PAI-1 and TF.

Results:

(Pre)adipocyte CM significantly enhanced the production of PAI-1 by HepG2 cells 2.5- to 4.4-fold. CM from cytokine-stimulated (pre)adipocytes significantly induced fibrinogen secretion 1.5- to 4.2-fold. TF production was not affected by the CM. After specific depletion of TNF-α, IL-1β or IL-6 from the CM, IL-6 was shown to be the most prominent stimulus of fibrinogen secretion and IL-1β of PAI-1 secretion. In addition, fibrinogen, PAI-1 and tissue factor production was evaluated by direct stimulation of HepG2 cells with TNF-α, IL-1β or IL-6. IL-6 enhanced fibrinogen synthesis 4.3-fold (P<0.01), whereas IL-1β induced PAI-1 production 5.0-fold (P<0.01). Gene expression analyses showed that TNF-α and IL-1β stimulate the adipocyte expression of TNF-α, IL-1β and IL-6. Cytokine stimulation of adipocytes may thus have induced an inflammatory response, which may have stimulated fibrinogen and PAI-1 production by HepG2 cells more potently.

Conclusions:

SGBS (pre)adipocytes release cytokines that increase the production of fibrinogen and PAI-1 by HepG2 cells. IL-6 and IL-1β produced by (pre)adipocytes were the strongest inducers of fibrinogen and PAI-1 secretion, respectively.

Plasminogen activator inhibitor 1 and visceral obesity during pronounced weight loss after bariatric surgery

BACKGROUND AND AIMS

Elevated plasminogen activator inhibitor 1 (PAI-1) concentrations are a hallmark of obesity and are considered to contribute to the development of cardiovascular disease. As adipose tissue constitutes a major source for PAI-1 in obesity, we investigated the individual contribution of subcutaneous and intra-abdominal fat on PAI-1 concentrations during pronounced weight loss after bariatric surgery.

METHODS AND RESULTS

Thirty-seven obese adults were examined before and 18 months after surgery. Abdominal fat distribution was determined by ultrasound, metabolic parameters and plasma PAI-1 levels by standard methods. BMI was reduced by 9.2 ± 4.9 kg/m(2), while total fat mass and visceral fat diameter (VFD) decreased by 20.7 ± 11.9 kg and 4.2 ± 2.3 cm, respectively. Concomitantly, PAI-1 levels diminished by 3.2 ± 5.6 ng/ml (all p ≤ 0.015). Change in PAI-1 levels was correlated with change in VFD (r = 0.441, p = 0.008), but not with subcutaneous fat diameter. In stepwise multiple regression analysis change in VFD was an independent predictor of change in PAI-1 concentrations. When adjusted for age and sex or total fat mass associations between PAI-1 and VFD remained significant.

CONCLUSION

We demonstrate that VFD is a major determinant for PAI-1 concentrations during pronounced weight loss after bariatric surgery. Thus, significant reduction of visceral fat mass may contribute to the reduced cardiovascular morbidity and mortality after bariatric surgery by a concomitant decrease in PAI-1 concentrations.

Elevated body mass index and risk of postoperative CSF leak following transsphenoidal surgery

OBJECT

Postoperative CSF leakage can be a serious complication after a transsphenoidal surgical approach. An elevated body mass index (BMI) is a significant risk factor for spontaneous CSF leaks. However, there is no evidence correlating BMI with postoperative CSF leak after transsphenoidal surgery. The authors hypothesized that patients with elevated BMI would have a higher incidence of CSF leakage complications following transsphenoidal surgery.

METHODS

The authors conducted a retrospective review of 121 patients who, between August 2005 and March 2010, underwent endoscopic endonasal transsphenoidal surgeries for resection of primarily sellar masses. Patients requiring extended transsphenoidal approaches were excluded. A multivariate statistical analysis was performed to investigate the association of BMI and other risk factors with postoperative CSF leakage.

RESULTS

In 92 patients, 96 endonasal endoscopic transsphenoidal surgeries were performed that met inclusion criteria. Thirteen postoperative leaks occurred and required subsequent treatment, including lumbar drainage and/or reoperation. The average BMI of patients with a postoperative CSF leak was significantly greater than that in patients with no postoperative CSF leak (39.2 vs 32.9 kg/m(2), p = 0.006). Multivariate analyses indicate that for every 5-kg/m(2) increase in BMI, patients undergoing a transsphenoidal approach for a primarily sellar mass have 1.61 times the odds (95% CI 1.10-2.29, p = 0.016, by multivariate logistic regression) of having a postoperative CSF leak.

CONCLUSIONS

Elevated BMI is an independent predictor of postoperative CSF leak after an endonasal endoscopic transsphenoidal approach. The authors recommend that patients with BMI greater than 30 kg/m(2) have meticulous sellar reconstruction at surgery and close monitoring postoperatively.

Role of surrogate markers of atherosclerosis in clinical and subclinical thyroidism

Background. Data on the relationship between homocysteine, plasminogen activator inhibitor 1, hs-CRP, fibrinogen, and carotid intima media thickness (CA-IMT) is plenty but contradicting and the majority of the studies investigated this issue in only specific thyroidism groups. The aim of this paper was to investigate these relations in patients with subclinical and clinical hypo- and hyperthyroidism. Methods. In this cross-sectional study, 16 patients from each thyroidism group and 20 healthy cases were enrolled. Fibrinogen levels and plasminogen activator inhibitor 1 (PAI-1) activity were assessed. CA-IMT was determined by gray-scale high-resolution color Doppler ultrasound. Results. Serum homocysteine levels were higher in hypothyroidic patients compared to the control (P = 0.003). Fibrinogen levels were higher in patients with subclinical hypothyroidism compared to other groups (P < 0.05). There was no difference between groups regarding PAI-1. Whereas total cholesterol, homocysteine, and LDL were correlated with CAIMT, hs-CRP, PAI-1, and fibrinogen were not. In the clinical hypothyroidism group, the correlation of homocysteine with CA-IMT was derived from the correlation between CA-IMT and homocysteine. Conclusions. Homocysteine and fibrinogen levels are higher in patients with clinical and subclinical hypothyroidism, respectively. Homocysteine level is associated with CA-IMTonly in patients with clinical hypothyroidism.

New strategies in pancreatic cancer: emerging epidemiologic and therapeutic concepts

Pancreatic cancer (PC) is a highly lethal disease with complex etiology involving both environmental and genetic factors. Although cigarette smoking is known to explain 25% of cases, data from recent studies suggest that obesity and long-term type II diabetes are two major modifiable risk factors for PC. Furthermore, obesity and diabetes seem to affect the clinical outcome of patients with PC. Understanding the mechanistic effects of obesity and diabetes on the pancreas may identify new strategies for prevention or therapy. Experimental and epidemiologic evidence suggests that the antidiabetic drug metformin has protective antitumor activity in PC. In addition to insulin resistance and inflammation as mechanisms of carcinogenesis, obesity and diabetes are linked to impairments in endothelial function and coagulation status, which increase the risks of thrombosis and angiogenesis and, in turn, the risk of PC development and progression. The associations of the ABO blood group gene and NR5A2 gene variants with PC discovered by recent genome-wide association studies may link insulin resistance, inflammation, and thrombosis to pancreatic carcinogenesis. These exciting findings open new avenues for understanding the etiology of PC and provide opportunities for developing novel strategies for prevention and treatment of this disease.

Release of inflammatory mediators by human adipose tissue is enhanced in obesity and primarily by the nonfat cells: a review

This paper considers the role of putative adipokines that might be involved in the enhanced inflammatory response of human adipose tissue seen in obesity. Inflammatory adipokines [IL-6, IL-10, ACE, TGFbeta1, TNFalpha, IL-1beta, PAI-1, and IL-8] plus one anti-inflammatory [IL-10] adipokine were identified whose circulating levels as well as in vitro release by fat are enhanced in obesity and are primarily released by the nonfat cells of human adipose tissue. In contrast, the circulating levels of leptin and FABP-4 are also enhanced in obesity and they are primarily released by fat cells of human adipose tissue. The relative expression of adipokines and other proteins in human omental as compared to subcutaneous adipose tissue as well as their expression in the nonfat as compared to the fat cells of human omental adipose tissue is also reviewed. The conclusion is that the release of many inflammatory adipokines by adipose tissue is enhanced in obese humans.

Plasminogen activator inhibitor-1 is associated with coronary artery calcium in Type 1 diabetes

BACKGROUND

Elevated levels of plasminogen activator inhibitor-1 (PAI-1), the major inhibitor of fibrinolysis, is associated with coronary artery disease (CAD). This association may not be independent of factors related to insulin resistance (IR). Patients with Type 1 diabetes mellitus have increased CAD and an increase in sub-clinical CAD which develops earlier in life. It is not known if PAI-1 is associated with sub-clinical CAD in Type 1 diabetes or if this association is independent of IR.

METHODS AND RESULTS

Type 1 diabetes patients (n=560) and participants without diabetes (n=693) were assessed for coronary artery calcium (CAC), a surrogate for subclinical CAD, by electron-beam computed tomography. PAI-1 was associated with CAC in both Type 1 diabetes (OR=1.32, 95% CI=1.12-1.58) and non-diabetes (OR=1.34, 95% CI=1.13-1.58), after controlling for traditional risk factors not associated with IR. In Type 1 diabetes, the relationship between PAI-1 and CAC was strongest for younger participants (P=.02 for PAI-1-by-age interaction) after controlling for factors related to IR. PAI-1 was positively associated with CAC for Type 1 diabetes participants younger than 45 years of age.

CONCLUSION

PAI-1 levels are independently related to CAC in younger Type 1 diabetes participants. PAI-1 levels were not independently related to CAC in non-diabetes participants.

Role of adipose tissue in haemostasis, coagulation and fibrinolysis

Obesity is associated with an increased incidence of insulin resistance (IR), type 2 diabetes mellitus and cardiovascular diseases. The increased risk for cardiovascular diseases could partly be caused by a prothrombotic state that exists because of abdominal obesity. Adipose tissue induces thrombocyte activation by the production of adipose tissue-derived hormones, often called adipokines, of which some such as leptin and adiponectin have been shown to directly interfere with platelet function. Increased adipose tissue mass induces IR and systemic low-grade inflammation, also affecting platelet function. It has been demonstrated that adipose tissue directly impairs fibrinolysis by the production of plasminogen activator inhibitor-1 and possibly thrombin-activatable fibrinolysis inhibitor. Adipose tissue may contribute to enhanced coagulation by direct tissue factor production, but hypercoagulability is likely to be primarily caused by affecting hepatic synthesis of the coagulation factors fibrinogen, factor VII, factor VIII and tissue factor, by releasing free fatty acids and pro-inflammatory cytokines (tumour necrosis factor-alpha, interleukin-1beta and interleukin-6) into the portal circulation and by inducing hepatic IR. Adipose tissue dysfunction could thus play a causal role in the prothrombotic state observed in obesity, by directly and indirectly affecting haemostasis, coagulation and fibrinolysis.

The omentum: anatomical, metabolic, and surgical aspects

INTRODUCTION

The omentum is acknowledged to have diverse functions in the pathophysiology of intra-abdominal disease. Its angiogenic properties act as a natural defense mechanism in peritonitis and intra-abdominal sepsis. With advancing technology the omentum is revealing itself as a new player in the field of molecular surgery with special reference to cancer, obesity and tissue reconstruction.

MATERIALS AND METHODS

This article reviews the existing and potential surgical applications of the omentum.

Getting the message across: mechanisms of physiological cross talk by adipose tissue

Obesity is associated with resistance of skeletal muscle to insulin-mediated glucose uptake, as well as resistance of different organs and tissues to other metabolic and vascular actions of insulin. In addition, the body is exquisitely sensitive to nutrient imbalance, with energy excess or a high-fat diet rapidly increasing insulin resistance, even before noticeable changes occur in fat mass. There is a growing acceptance of the fact that, as well as acting as a storage site for surplus energy, adipose tissue is an important source of signals relevant to, inter alia, energy homeostasis, fertility, and bone turnover. It has also been widely recognized that obesity is a state of low-grade inflammation, with adipose tissue generating substantial quantities of proinflammatory molecules. At a cellular level, the understanding of the signaling pathways responsible for such alterations has been intensively investigated. What is less clear, however, is how alterations of physiology, and of signaling, within one cell or one tissue are communicated to other parts of the body. The concepts of cell signals being disseminated systemically through a circulating "endocrine" signal have been complemented by the view that local signaling may similarly occur through autocrine or paracrine mechanisms. Yet, while much elegant work has focused on the alterations in signaling that are found in obesity or energy excess, there has been less attention paid to ways in which such signals may propagate to remote organs. This review of the integrative physiology of obesity critically appraises the data and outlines a series of hypotheses as to how interorgan cross talk takes place. The hypotheses presented include the "fatty acid hypothesis,", the "portal hypothesis,", the "endocrine hypothesis,", the "inflammatory hypothesis,", the "overflow hypothesis,", a novel "vasocrine hypothesis," and a "neural hypothesis," and the strengths and weaknesses of each hypothesis are discussed.

Adipokines, inflammation, and visceral adiposity across the menopausal transition: a prospective study

CONTEXT

Postmenopausal women have greater visceral adiposity compared with premenopausal women. Adipokines are associated with increased adiposity, insulin resistance, and atherosclerosis.

OBJECTIVE

The objective of the study was to assess changes in adipokines and inflammatory markers through the menopausal transition and correlate them with changes in visceral adiposity.

DESIGN AND SETTING

This was a prospective cohort study of women through the menopausal transition conducted at the University of Washington.

PARTICIPANTS

Sixty-nine healthy women were followed up longitudinally from premenopausal (aged 45-55 yr) to postmenopausal status (aged 49-60 yr).

OUTCOME

On premenopausal and postmenopausal visits, fasting blood was drawn for adiponectin, leptin, serum amyloid A (SAA), C-reactive protein (CRP), monocyte-chemotactic protein-1, tissue plasminogen activator antigen (tPA), IL-6, and TNF-alpha. Body composition measures were assessed by body mass index, whole-body dual x-ray absorptiometry scan, and computed tomography scan of the abdomen at the lumbar 4-5 level.

RESULTS

Women had a statistically significant increase in SAA, tPA, monocyte-chemotactic protein-1, and adiponectin between the two measurement occasions (P = 0.04, P = 0.02, P = 0.001, and P < 0.001, respectively). The increase in intraabdominal fat was correlated positively with the change in SAA (r = 0.31, P = 0.02), CRP (r = 0.56, P < 0.001), tPA (r = 0.40, P = 0.002), and leptin (r = 0.41, P = 0.002) and negatively correlated with the change in adiponectin (r = -0.37, P = 0.005). After adjustment for change in sc abdominal fat, the correlation between change in CRP, tPA, leptin, and adiponectin remained significantly associated with change in intraabdominal fat.

CONCLUSIONS

Women going through the menopausal transition have deleterious changes in inflammatory markers and adipokines that correlate with increased visceral adiposity.

Regulation of Microvascular Function by Adipose Tissue in Obesity and Type 2 Diabetes: Evidence of an Adipose-Vascular Loop

In recent years, the general concept has emerged that chronic low-grade inflammation is the condition linking excessive development of adipose tissue and obesity-associated pathologies such as type 2 diabetes and cardiovascular diseases. Obesity and type 2 diabetes are characterized by a diminished production of protective factors such as adiponectin and increased detrimental adipocytokines such as leptin, resistin, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNFα), and monocyte chemoattractant protein-1 (MCP-1) by adipose tissue. Moreover, the evidence that the growth of the fat mass is associated with an accumulation of adipose tissue macrophages and T-lymphocytes has raised the hypothesis that the development of an inflammatory process within the growing fat mass is a primary event involved in the genesis of systemic metabolic and vascular alterations. This crosstalk of adipocyte, macrophage, lymphocyte, endothelial cells, and vascular smooth muscle cells contribute to the production of various cytokines, chemokines, and hormone-like factors, which actively participate in the regulation of vascular function by an endocrine and/or paracrine pattern. Thus, the signaling from perivascular adipose to the blood vessels is emerging as a potential therapeutic target for obesity and diabetes-associated vascular dysfunction.

Correlation between omental TNF-α protein and plasma PAI-1 in obesity subjects

BACKGROUND

The role of TNF-alpha in contributing to obesity-associated cardiovascular and metabolic risk has gained much attention.

MATERIALS AND METHODS

Paired biopsies of omental and subcutaneous fat were collected from 16 lean subjects and 32 central obesity subjects. The expression of TNF-alpha in omental and subcutaneous fat was quantified by western blotting method, and correlations with plasma PAI-1, homeostasis model assessment insulin resistance (HOMA-IR), and lipid were investigated.

RESULTS

In obese female, TNF-alpha expression was higher in the omental than in the subcutaneous fat tissue. There was no significant difference in the levels of TNF-alpha between subcutaneous and visceral fat in obese male. Significant positive correlations were found between omental TNF-alpha protein and plasma PAI-1 levels in obesity. In obese female subjects, omental TNF-alpha protein levels showed a close association with most of the parameters studied: fasting glucose (r=0.541, P<0.05); fasting insulin (r=0.599, P<0.01); HOMA-IR (r=0.546, P<0.05); triglycerides (r=0.469, P<0.05); HDL-cholesterol (r=-0.759, P<0.01). In obese male population, correlations between omental TNF-alpha protein levels and fasting glucose (r=0.762, P<0.01); fasting insulin (r=0.622, P<0.05); triglycerides (r=0.650, P<0.05); HDL-cholesterol (r=-0.880, P<0.01) were found.

CONCLUSION

Omental TNF-alpha may play a key role in contributing to cardiovascular risk in central obesity subjects.

Visceral adiposity is associated with serum retinol binding protein-4 levels in healthy women

OBJECTIVE

Retinol binding protein-4 (RBP4) has been reported to impair insulin sensitivity throughout the body. We investigated the relationship between serum RBP4 levels and adiposity indices as well as metabolic risk variables.

RESEARCH METHODS AND PROCEDURE

We recruited a total of 102 healthy women 21 to 67 years old. We assessed body composition by computed tomography and divided the study population into four groups based on body weight and visceral fat area (non-obese without visceral adiposity, non-obese with visceral adiposity, obese without visceral adiposity, and obese with visceral adiposity). Serum RBP4 levels were measured by radioimmunoassay.

RESULTS

Despite similar levels of total body fat, non-obese women had lower systolic blood pressure, total cholesterol, triglyceride (TG), low-density lipoprotein (LDL)-cholesterol levels, insulin resistance indices, and RBP4 levels than non-obese women with visceral adiposity and had higher high-density lipoprotein-cholesterol levels. Similarly, obese women without visceral adiposity had lower blood pressure, total cholesterol, TG levels, insulin resistance indices, and RBP4 levels than obese women with visceral adiposity. In addition, despite having increased body fat, obese women without visceral adiposity had lower TGs, insulin resistance indices, and serum RBP4 levels than non-obese women with visceral adiposity. By step-wise multiple regression analysis, visceral fat areas and LDL-cholesterol levels independently affected RBP4 levels.

DISCUSSION

We determined that serum RBP4 levels are independently associated with visceral fat and LDL-cholesterol levels. These results suggest that, irrespective of body weight, visceral obesity is an independent predictor of serum RBP4 levels, and RBP4 may represent a link between visceral obesity and cardiovascular disease.

Review: Peroxisome proliferator-activated receptor gamma and adipose tissue--understanding obesity-related changes in regulation of lipid and glucose metabolism

CONTEXT

Adipose tissue is a metabolically dynamic organ, serving as a buffer to control fatty acid flux and a regulator of endocrine function. In obese subjects, and those with type 2 diabetes or the metabolic syndrome, adipose tissue function is altered (i.e. adipocytes display morphological differences alongside aberrant endocrine and metabolic function and low-grade inflammation).

EVIDENCE ACQUISITION

Articles on the role of peroxisome proliferator-activated receptor gamma (PPARgamma) in adipose tissue of healthy individuals and those with obesity, metabolic syndrome, or type 2 diabetes were sourced using MEDLINE (1990-2006).

EVIDENCE SYNTHESIS

Articles were assessed to provide a comprehensive overview of how PPARgamma-activating ligands improve adipose tissue function, and how this links to improvements in insulin resistance and the progression to type 2 diabetes and atherosclerosis.

CONCLUSIONS

PPARgamma is highly expressed in adipose tissue, where its activation with thiazolidinediones alters fat topography and adipocyte phenotype and up-regulates genes involved in fatty acid metabolism and triglyceride storage. Furthermore, PPARgamma activation is associated with potentially beneficial effects on the expression and secretion of a range of factors, including adiponectin, resistin, IL-6, TNFalpha, plasminogen activator inhibitor-1, monocyte chemoattractant protein-1, and angiotensinogen, as well as a reduction in plasma nonesterified fatty acid supply. The effects of PPARgamma also extend to macrophages, where they suppress production of inflammatory mediators. As such, PPARgamma activation appears to have a beneficial effect on the relationship between the macrophage and adipocyte that is distorted in obesity. Thus, PPARgamma-activating ligands improve adipose tissue function and may have a role in preventing progression of insulin resistance to diabetes and endothelial dysfunction to atherosclerosis.

Peroxisome proliferator-activated receptor-gamma agonists for management and prevention of vascular disease in patients with and without diabetes mellitus

Inflammation is known to have a pathogenic role in atherosclerosis and the genesis of acute coronary syndromes. The peroxisome proliferator-activated receptor (PPAR)-gamma, which is expressed in many constituent cells of atheromatous plaques, inhibits the activation of several proinflammatory genes responsible for atheromatous plaque development and maturation. Agonists of this receptor, such as rosiglitazone and pioglitazone, are currently available for the treatment of type 2 diabetes mellitus, and several lines of evidence have shown that these drugs have antiatherogenic effects. Insulin resistance is associated with inflammation and has a key role in atherogenesis. The antiatherogenic and insulin sensitizing effects of the thiazolidinediones in patients with type 2 diabetes mellitus may be associated with this action. However, in recent years there has been growing evidence that the antiatherogenic effects of PPAR-gamma agonists are not confined to patients with diabetes mellitus. PPAR-gamma agonists have been shown to downregulate the expression of endothelial activation markers, reduce circulating platelet activity, improve flow-mediated dilatation and attenuate atheromatous plaque progression in patients without diabetes mellitus. These effects of PPAR-gamma agonists appear to result from both insulin sensitization and a direct modulation of transcriptional activity in the vessel wall. This review summarizes the current understanding of the role of PPAR-gamma agonists in atherogenesis and discusses their potential role in the treatment of coronary artery disease in patients with type 2 diabetes mellitus and in nondiabetic patients.

Biology of stem cells in human umbilical cord stroma: in situ and in vitro surveys

Cells in the umbilical cord stroma have gained attention in recent years; however, differentiation to certain lineages in humans has been demonstrated in few studies. Unlike bone marrow MSCs, human umbilical cord stroma cells (HUCSCs) are far from being well characterized. This study attempts to describe proliferation, structural, and differentiation properties of these cells to account for their exceptional nature in many aspects. Cellular dynamics, cellular structure, and the degree of transformations during expansion and differentiation into mesenchymal and neuronal lineages were examined in vitro over a 10-month period. Comparisons with human bone marrow MSCs regarding differentiation were performed. HUCSCs in culture revealed two distinct cell populations, type 1 and type 2 cells, that possessed differential vimentin and cytokeratin filaments. Corresponding cells were encountered in cord sections displaying region-specific localization. alpha-Smooth muscle actin and desmin filaments, which were evident in cord sections, diminished through passages. No difference was noted regarding type 1 and type 2 cells in differentiation to chondrogenic, adipogenic, and osteogenic lineages, whereas a preferential differentiation was noted in neuronal lineage. Relative success was achieved by production of chondrocytic spheres and osteogenic monolayers, whereas adipocytes were immature compared with bone marrow MSCs. The presence of neuronal markers suggests that they transform into a certain state of maturity under neurogenic induction. Conclusively, HUCSCs retain their original phenotype in culture without spontaneous differentiation, have a limited lifespan, and bear multipotent stem cell characteristics. Given these characteristics, they may be generally considered progenitor cells if manipulated under appropriate conditions and deserve further study to be potentially used in cell-based therapies.

Bone Marrow Plasminogen Activator Inhibitor-1 Influences the Development of Obesity

Plasma levels of plasminogen activator inhibitor-1 (PAI-1) are elevated in obesity and correlate with body mass index. The increase in PAI-1 associated with obesity likely contributes to increased cardiovascular risk and may predict the development of type 2 diabetes mellitus. Although adipocytes are capable of synthesizing PAI-1, the bulk of evidence indicates that cells residing in the stromal fraction of visceral fat are the primary source of PAI-1. We hypothesized that bone marrow-derived PAI-1, e.g. derived from macrophages located in visceral fat, contributes to the development of diet-induced obesity. To test this hypothesis, male C57BL/6 wild-type mice and C57BL/6 PAI-1 deficient mice were transplanted with either PAI-1(-/-), PAI-1(+/-), or PAI-1(+/+) bone marrow. The transplanted animals were subsequently fed a high fat diet for 24 weeks. Our findings show that only the complete absence of PAI-1 protects from the development of diet-induced obesity, whereas the absence of bone marrow-derived PAI-1 protects against expansion of the visceral fat mass. Remarkably, there is a link between the PAI-1 levels, the degree of inflammation in adipose tissue, and the development of obesity. Based on these findings we suggest that bone marrow-derived PAI-1 has an effect on the development of obesity through its effect on inflammation.

Plasminogen activator inhibitor type 1 (PAI-1) in plasma and adipose tissue in HIV-associated lipodystrophy syndrome. Implications of adipokines

BACKGROUND

PAI-1, an important inhibitor of fibrinolysis, is increased in obese subjects and has been shown to be an independent risk factor for cardiovascular disease. In the present study, we investigated the association between circulating levels of PAI-1 and locally produced PAI-1 in adipose tissue and body fat distribution and adipokines (TNF-alpha, TNF receptors, IL-6, IL-8) in patients with and without HIV-associated lipodystrophy syndrome (HALS).

MATERIALS AND METHODS

Eighteen men with HALS and 18 men with HIV but without HALS were investigated. DEXA and computed tomography scan were performed to determine total body fat and visceral adipose tissue mass. Insulin sensitivity was determined by the euglycaemic clamp technique. Plasma levels of PAI-1 and cytokines were determined. In addition, PAI-1, TNF-alpha, IL-6 and IL-8 mRNA levels in subcutaneous adipose tissue were measured by real-time reverse transcriptase polymerase chain reaction.

RESULTS

HALS patients were characterized by a 3-fold increased visceral adipose tissue (P < 0.001) and reduced limb fat (P < 0.01) as compared with non-HALS patients but with no difference in total fat mass between the groups. Plasma PAI-1 was increased in HALS patients (16.7 ng mL(-1) vs. 8.2 ng mL(-1), P < 0.05). Plasma PAI-1 was positively correlated with BMI (r = 0.74, P < 0.01), plasma TNF-alpha level (r = 0.64, P < 0.01), sTNFR-I (r = 0.38, P < 0.05), and visceral fat (r = 0.67, P < 0.01). Moreover, plasma PAI-1 was negatively associated with insulin sensitivity (r = -0.57, P < 0.01) and the percentage of limb fat (r = -0.57, P < 0.01). A positive correlation was found between plasma PAI-1 and TNF-alpha mRNA level. No association was, however, found between plasma PAI-1 and PAI-1 mRNA level in adipose tissue.

CONCLUSION

Plasma PAI-1 is increased in HALS patients and it is suggested that dysregulation of the TNF-system (high TNFalpha and high sTNFR1) may play a role in up-regulating PAI-1 in HALS.

Role of macrophage tissue infiltration in metabolic diseases

PURPOSE OF REVIEW

White adipose tissue is necessary for optimal energy homeostasis and the excessive development of fat mass is clearly associated with the metabolic syndrome. The fact that adipocytes secrete a number of specific factors or 'adipokines' has forced a reassessment of the involvement of adipose tissue in a wide range of physiological and pathophysiological processes. Obesity has recently been described as a 'low-grade' inflammatory condition, a state proposed to represent a common determinator in the genesis of obesity-associated pathologies, i.e. diabetes and atherosclerosis.

RECENT FINDINGS

Recent reports of an increase in the number of macrophages that infiltrate the fat mass in obese individuals led to the suggestion that adipose tissue itself is a source and site of inflammation.

SUMMARY

This review summarizes recent data on the characterization of the macrophage population in fat tissue. Their origin, fate and activation will be considered. The potential involvement of adipose tissue macrophages in the development of insulin resistance and vascular pathologies, as well as in the control of adipose tissue growth and metabolism, will be examined.

Inflammatory Cytokines Interleukin-6 and Oncostatin M Induce Plasminogen Activator Inhibitor-1 in Human Adipose Tissue

Background— Adipose tissue is a prominent source of plasminogen activator inhibitor-1 (PAI-1), the primary physiological inhibitor of plasminogen activation. Increased PAI-1 expression acts as a cardiovascular risk factor, and plasma levels of PAI-1 strongly correlate with body mass index (BMI). Elevated serum levels of interleukin-6 (IL-6), an inflammatory cytokine and a member of the glycoprotein 130 (gp130) ligand family, are found in obese patients and might indicate low-grade systemic inflammation. Another gp130 ligand, oncostatin M (OSM), upregulates PAI-1 in cardiac myocytes, astrocytes, and endothelial cells. We used tissue explants and primary cultures of preadipocytes and adipocytes from human subcutaneous and visceral adipose tissue to investigate whether IL-6 and OSM affect PAI-1 expression in fat.

Methods and Results— Human subcutaneous and visceral adipose tissue responded to treatment with IL-6 and OSM with a significant increase in PAI-1 production. Human preadipocytes were isolated from subcutaneous and visceral adipose tissue. Adipocyte differentiation was induced by hormone supplementation. All cell types expressed receptors for IL-6 and OSM and produced up to 12-fold increased levels of PAI-1 protein and up to 9-fold increased levels of PAI-1 mRNA on stimulation with IL-6 and OSM. AG-490, a janus kinase/signal transducer and activator of transcription inhibitor, abolished the OSM-dependent PAI-1 induction almost completely.

Conclusions— We have for the first time established a link between the gp130 ligands, the proinflammatory mediators IL-6 and OSM, and the expression of PAI-1 in human adipose tissue. Thus, we speculate that IL-6 and OSM, by upregulating PAI-1 in adipose tissue, can contribute to the increased cardiovascular risk of obese patients.

Comparison of Gene Expression in Intra-Abdominal and Subcutaneous Fat: A Study of Men with Morbid Obesity and Nonobese Men Using Microarray and Proteomics

Extent of intra-abdominal fat had significant linear relations with six metabolic coronary risk factors: systolic and diastolic blood pressure, fasting blood concentrations of glucose, high density lipoprotein (HDL) cholesterol, triglyceride, and plasminogen activator inhibitor-1. Tumor necrosis factor-alpha and adiponectin can be biological mediators from the intra-abdominal fat to the metabolic coronary risk factors. Complementarily, we describe a new study that will analyze the gene expression in intra-abdominal and subcutaneous fat on mRNA and protein level using high throughput methods. The study will elucidate further whether intra-abdominal obesity is the common denominator for the different components of the metabolic syndrome.

Lower expression of adiponectin mRNA in visceral adipose tissue in lean and obese subjects

Adiponectin is an adipocyte-specific protein suggested to play a role in mediating the metabolic effects of obesity. In the present study, we investigated adiponectin mRNA levels in both visceral and subcutaneous abdominal adipose tissue (AT) from lean and obese subjects. Investigations on both "fresh" fat biopsies and incubations of AT fragments were performed. Regional differences in the effects of the cytokine interleukin-1beta (IL-1beta) were investigated. Adiponectin gene expression was 33% lower in visceral AT than in subcutaneous AT of lean subjects (P < 0.05), and 28% lower in obese subjects, albeit non-significant (P = 0.3). In both lean and obese subjects adiponectin mRNA expression in incubated AT fragments was significantly lower in visceral AT than in subcutaneous AT (lean: P < 0.01; obese: P < 0.05). No difference was found in adiponectin mRNA levels in gluteal compared to abdominal subcutaneous AT. IL-1beta suppressed adiponectin mRNA levels substantially in both subcutaneous and visceral AT. In conclusion, adiponectin gene expression is lower in visceral AT than in subcutaneous abdominal AT, suggesting subcutaneous AT to be more important for circulating adiponectin levels.

Is plasminogen activator inhibitor-1 a cardiovascular risk factor in young women with polycystic ovary syndrome?

This study aimed to evaluate plasminogen activator inhibitor-1 (PAI-1) activity in PCOS. Thirty women with PCOS - 15 normal-weight and 15 obese - and 30 healthy women matched as a group for age and body mass index (BMI) were recruited. The homeostasis model assessment (HOMA) score was significantly elevated in obese compared with normal-weight women, in both PCOS women and controls. HOMA score was significantly higher in both PCOS groups relative to controls. After further adjustment for BMI, PAI-1 activity (IU/ml +/- SD) was significantly higher in the PCOS groups compared with controls. A significant positive correlation was found between HOMA score and BMI in PCOS and control groups. Serum PAI-1 activity was significantly related to BMI and HOMA score. When considering two BMI subgroups, there was no significant difference in the relationship between serum PAI-1 activity and HOMA score in both the control and PCOS groups. No other significant relationship was found between serum PAI-1 activity and any other hormonal or metabolic parameter. In conclusion, women with PCOS have significantly elevated PAI-1 activity independent of obesity, and it is speculated that elevated PAI-1 activity may be a factor in the increased cardiovascular morbidity seen in PCOS.

Stimulation of PAI-1 and adipokines by glucose in human adipose tissue in vitro

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.