Association of plasminogen activator inhibitor-1 with insulin resistance in Japan where obesity is rare

The Impact of Insulin Resistance and Chronic Kidney Disease on Inflammation and Cardiovascular Disease

There is extensive evidence showing that insulin resistance (IR) is associated with chronic low-grade inflammation. Furthermore, IR has been shown to increase the risk for cardiovascular disease (CVD), even in nondiabetic patients, and is currently considered as a “nontraditional” risk factor contributing to CVD by promoting hypertension, oxidative stress, endothelial dysfunction, dyslipidemia, and type 2 diabetes mellitus. However, chronic kidney disease (CKD) is also considered a state of low-grade inflammation. In addition, CKD is considered an IR state and has been described as an independent risk factor for the development of CVD, as even early-stage CKD is associated with an estimated 40% to 100% increase in CVD risk. There is also strong evidence indicating that inflammation per se plays a crucial role in both the initiation and progression of CVD. Given the above, the combined effect of IR and CKD may significantly increase the risk of inflammation and CVD. This review aims to focus on the complex interplay between IR, CKD, inflammation, and CVD and will present and discuss the current clinical and scientific data pertaining to the impact of IR and CKD on inflammation and CVD.

Relation of antioxidant capacity of diet and markers of oxidative status with C-reactive protein and adipocytokines: a prospective study

BACKGROUND

The role of dietary antioxidants and plasma oxidant-antioxidant status in low-grade chronic inflammation and adipocytokine levels is not established yet.

OBJECTIVES

We aimed to evaluate whether total dietary antioxidant capacity (assessed by dietary ferric reducing antioxidant potential (FRAP)), serum uric acid (UA) and gamma glutamyltransferase (GGT) were associated with low-grade chronic inflammation and circulating adipocytokines.

METHODS

Data of 4506 participants aged ≥55years from the Rotterdam Study were analyzed. Baseline (1990-1993) FRAP score was assessed by a food frequency questionnaire. Baseline UA and GGT levels were assessed in non-fasting serum samples. Serum high sensitivity C-reactive protein (hs-CRP) was measured at baseline and 10years later. Plasma leptin, adiponectin, plasminogen activator inhibitor-1 (PAI-1) and resistin levels were assessed 10years later.

RESULTS

A high FRAP score was associated with lower levels of UA and GGT. Overall, no association was found between FRAP and hs-CRP levels. FRAP score was associated with lower levels of leptin and PAI-1, higher levels of adiponectin, and no difference in resistin levels. Increased levels of UA were associated with higher levels of hs-CRP, PAI-1 and leptin; lower levels of adiponectin and no difference in resistin levels. Similarly, GGT was associated with higher levels of hs-CRP whereas no association was observed between GGT and adipocytokines.

CONCLUSION

These findings suggest that overall antioxidant capacity of diet and low levels of UA are associated with circulating adipocytokines whereas no consistent association was found with hs-CRP.

Effects of Two Different Dietary Patterns on Inflammatory Markers, Advanced Glycation End Products and Lipids in Subjects without Type 2 Diabetes: A Randomised Crossover Study

Epidemiological studies suggest that consumption of red and processed meat and refined grains are associated with type 2 diabetes and metabolic syndrome and increased inflammatory and fibrinolytic markers. We hypothesised that a diet high in red and processed meat and refined grains (HMD) would increase inflammatory markers and advanced glycation end products (AGEs) compared with a diet high in dairy, whole grains, nuts and legumes (HWD). We performed a randomised crossover study of two four-week interventions in 51 participants without type 2 diabetes (15 men and 36 women aged 35.1 ± 15.6 years; body mass index: 27.7 ± 6.9 kg/m²). No baseline measurements were performed. Plasma fluorescent AGEs, carboxymethyllysine, glucose, insulin, lipids, hs-CRP, interleukin 6 (IL-6) and plasminogen activator inhibitor-1 (PAI-1) were analysed after four weeks on each diet. IL-6, hs-CRP, AGEs and carboxymethyllysine were not different between diets but PAI-1 was higher after the HMD than after HWD ((median and interquartile range) 158, 81 vs. 121, 53 ng/mL p < 0.001). PAI-1 on the HWD diet was inversely correlated with whole grains intake (p = 0.007). PAI-1 was inversely correlated with insulin sensitivity index (r = −0.45; p = 0.001) and positively correlated with serum total cholesterol (r = 0.35; p = 0.012) and serum triglyceride (r = 0.32; p = 0.021) on HMD. This trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12614000519651).

The metabolic syndrome and inflammation

The metabolic syndrome (MS) is a clustering of cardiovascular risk factors, with insulin resistance as a major feature. This syndrome has been variously defined, but generally consists of 3 or more of the following components: hyperglycemia, hypertension, hypertriglyceridemia, low HDL, and increased abdominal circumference and/or BMI at >30 kg/m(2). The WHO criteria require the presence of insulin resistance to make the diagnosis. The current review focuses particularly on the association of the MS and the proinflammatory state as well as treatment options to prevent the development of coronary heart disease (CHD). Chronic inflammation is frequently associated with the MS. Inflammatory markers that have been associated with MS include hs-CRP, TNF-alpha, fibrinogen, and IL-6, among others. The link between inflammation and the MS is not fully understood. One postulated mechanism is that these cytokines are released into the circulation by adipose tissue, stimulating hepatic CRP production. The prothrombotic molecule PAI-1 is also increased in the MS. Adiponectin, produced exclusively by adipocytes, is decreased in obesity. The association of these proinflammatory and prothrombotic markers with the MS is discussed in detail. The general goals of treatment of the MS are prevention of CHD events and diabetes if not already present. The approach to treatment of those with the MS should include lifestyle changes, including weight loss and exercise as well as appropriate pharmacological therapies. Certain medications, which may be used in persons with MS, have been shown to have beneficial effects on clinical outcome and/or anti-inflammatory effects.

Intake of phenol-rich virgin olive oil improves the postprandial prothrombotic profile in hypercholesterolemic patients

BACKGROUND

Oxidative stress associated with postprandial lipemia contributes to endothelial dysfunction, which shifts hemostasis to a more thrombogenic state.

OBJECTIVE

We investigated whether a high concentration of phenols in olive oil can partly reverse this phenomenon.

DESIGN

Twenty-one hypercholesterolemic volunteers received 2 breakfasts rich in olive oils with different phenolic contents (80 or 400 ppm) according to a randomized, sequential crossover design. Plasma concentrations of lipid fractions, factor VII antigen (FVIIag), activated factor VII (FVIIa), and plasminogen activator inhibitor-1 (PAI-1) activity were measured at baseline and postprandially.

RESULTS

Concentrations of FVIIa increased less (P = 0.018) and plasma PAI-1 activity decreased more (P = 0.021) 2 h after the high-phenol meal than after the low-phenol meal. FVIIa concentrations 120 min after intake of the olive oil with a high phenol content correlated positively with fasting plasma triacylglycerols (P = 0.001), area under the curve (AUC) of triacylglycerols (P = 0.001), and AUC of nonesterified fatty acids (P = 0.024) and negatively with hydroxytyrosol plasma concentrations at 60 min (P = 0.039) and fasting HDL-cholesterol concentrations (P = 0.005). PAI-1 positively correlated with homeostasis model assessment of insulin resistance (P = 0.005) and fasting triacylglycerols (P = 0.025) and inversely with adiponectin (P = 0.026). In a multivariate analysis, the AUCs of nonesterified fatty acids (R(2) = 0.467; beta: 0.787; SE: 0.02; P < 0.001) and adiponectin (R(2) = 0.232; beta: -1.594; SE: 0.629; P < 0.05) were the strongest predictors of plasma FVIIa and PAI-1, respectively.

CONCLUSIONS

A virgin olive oil with a high content of phenolic compounds changes the postprandial hemostatic profile to a less thrombogenic state.

Differences in the association of PAI-1 activity with the metabolic syndrome between African and Caucasian women

BACKGROUND AND AIMS

The association between PAI-1(act) and markers of the metabolic syndrome is well established in Caucasian populations, but data on African subjects is lacking. The aim of this study was to investigate possible differences between the association of PAI-1(act) and markers of the metabolic syndrome in Caucasian and African women.

METHODS AND RESULTS

Cross-sectional data were collected from 95 African and 114 Caucasian women in the Potchefstroom district of the North West Province, South Africa. Plasma PAI-1(act) was almost twice as high in Caucasians compared to Africans (10.2 versus 5.2 U/mL, p<0.001). Correlations between markers of the metabolic syndrome and PAI-1(act) were remarkably stronger in Caucasians than in Africans. In multivariate regression analyses 56% of the variance of PAI-1(act) could be explained by metabolic syndrome variables in the Caucasian group compared to 12% in the African women. Waist circumference was the strongest independent predictor of PAI-1(act) in both groups.

CONCLUSION

This study showed lower PAI-1(act) in African than in Caucasian women, along with less associations of PAI-1(act) with markers of the metabolic syndrome in the African than in the Caucasian women. The role of PAI-1(act) in the metabolic syndrome may be less prominent in Africans than in Caucasians.

Insulin resistance and atherosclerosis

The epidemic of obesity in the developed world over the last two decades is driving a large increase in type 2 diabetes and consequentially setting the scene for an impending wave of cardiovascular morbidity and mortality. It is only now being recognized that the major antecedent of type 2 diabetes, insulin resistance with its attendant syndrome, is the major underlying cause of the susceptibility to type 2 diabetes and cardiovascular disease. In metabolic tissues, insulin signaling via the phosphatidylinositol-3-kinase pathway leads to glucose uptake so that in insulin resistance a state of hyperglycemia occurs; other factors such as dyslipidemia and hypertension also arise. In cardiovascular tissues there are two pathways of insulin receptor signaling, one that is predominant in metabolic tissues (mediated by phosphatidylinositol-3-kinase) and another being a growth factor-like pathway (mediated by MAPK); the down-regulation of the former and continued activity of the latter pathway leads to atherosclerosis. This review addresses the metabolic consequences of the insulin resistance syndrome, its relationship with atherosclerosis, and the impact of insulin resistance on processes of atherosclerosis including insulin signaling in cells of the vasculature.

The determinants of plasma plasminogen activator inhibitor-1 levels differ for American and Japanese men aged 40-49

BACKGROUND

Elevated plasma plasminogen activator inhibitor-1 (PAI-1) levels were associated with higher incidence of type II diabetes. Elucidating the determinants of PAI-1 in various ethnicities may help to understand the susceptibility to developing diabetes. The aim of our study was to compare PAI-1 levels between Americans and the Japanese in the post-war generation and to elucidate the determinants of the PAI-1 levels.

METHODS

We conducted a cross-sectional study on a total of 198 men aged 40-49 in the US (Body mass index (BMI): 27.0+/-3.3 kg/m(2)) and Japan (BMI: 23.3+/-3.1 kg/m(2)). Examination included physique measurement (BMI and waist girth), blood analysis (lipid profiles, glucose, insulin, C-reactive protein, and PAI-1), and life-style assessment by self-administered questionnaires.

RESULTS

PAI-1 levels were significantly lower in American than in Japanese men, even after adjustment for age, waist girth, cigarette smoking, habitual alcohol drinking, and other factors. In the Americans, waist girth, insulin, and cigarette smoking were significantly associated with PAI-1 levels, while waist girth and triglycerides were significantly associated with PAI-1 levels in the Japanese.

CONCLUSIONS

PAI-1 levels were significantly lower in American than in Japanese men and the determinants of PAI-1 levels differ for American and Japanese men aged 40-49.

Cryptogenic cirrhosis in the region where obesity is not prevalent

AIM: Recent studies have demonstrated that obesity is the common feature of cryptogenic cirrhosis (CC) and non-alcoholic steatohepatitis. However, there is little information on CC in the region where obesity is not prevalent.

METHODS: The clinical features, and the liver-related morbidity and mortality of CC were analyzed in Japan where the prevalence of obesity is low. Among 652 cirrhotic patients, we identified 29 patients (4.4%) with CC. Of these, 24 CC patients who were followed up for more than 6 months were compared in a case-control study with age-, sex-, and Child-Pugh score-matched controls having cirrhosis of viral etiology.

RESULTS: Obesity (BMI≥25 kg/m²), diabetes mellitus, and hypertriglyceridemia were more frequent, and the visceral fat area was larger in the CC patients than in the controls. The indices of insulin resistance were higher and the serum aminotransferase levels were lower in the CC patients than in the controls. Logistic regression analysis identified the elevated hemoglobin A1c, BMI ≥ 25 kg/m², and normal aminotransferase levels as independent predictors of CC. Kaplan-Meier analysis demonstrated lower occurrence of hepatocellular carcinoma and higher survival rate in the CC than in the controls in contrast to the similar cumulative probability of liver-related morbidity between those groups.

CONCLUSION: CC more frequently presents with the clinical features suggestive of non-alcoholic steatohepatitis compared with controls even in the region where obesity is not prevalent. The lower occurrence of hepatocellular carcinoma and higher survival rate may indicate an indolent clinical course in CC as compared with viral cirrhosis.

Detecting insulin resistance in polycystic ovary syndrome: purposes and pitfalls

Approximately 50% to 70% of all women with polycystic ovary syndrome (PCOS) have some degree of insulin resistance, and this hormone insensitivity probably contributes to the hyperandrogenism that is responsible for the signs and symptoms of PCOS. Although uncertainty exists, early detection and treatment of insulin resistance in this population could ultimately reduce the incidence or severity of diabetes mellitus, dyslipidemia, hypertension, and cardiovascular disease. Even if that proves to be the case, there are still several problems with our current approach to insulin sensitivity assessment in PCOS, including the apparent lack of consensus on what defines PCOS and "normal" insulin sensitivity, ethnic and genetic variability, the presence of other factors contributing to insulin resistance such as obesity, stress, and aging, and concern about whether simplified models of insulin sensitivity have the precision to predict treatment needs, responses, and future morbidity. Although the hyperinsulinemic-euglycemic clamp technique is the gold standard for measuring insulin sensitivity, it is too expensive, time-consuming, and labor-intensive to be of practical use in an office setting. Homeostatic measurements (fasting glucose/insulin ratio or homeostatic model assessment [HOMA] value) and minimal model tests (particularly the oral glucose tolerance test [OGTT]) represent the easiest office-based assessments of insulin resistance in the PCOS patient. The OGTT is probably the best simple, office-based method to assess women with PCOS because it provides information about both insulin resistance and glucose intolerance. The diagnosis of glucose intolerance holds greater prognostic and treatment implications. All obese women with PCOS should be screened for the presence of insulin resistance by looking for other stigmata of the insulin resistance syndrome such as hypertension, dyslipidemia, central obesity, and glucose intolerance.