Fatty liver predicts the risk for cardiovascular events in middle-aged population: a population-based cohort study.

OBJECTIVE: We investigated if the differences in liver fat content would predict the development of non-fatal and fatal atherosclerotic endpoints (coronary heart disease and stroke). DESIGN, SETTING AND PARTICIPANTS: Our study group is a population-based, randomly recruited cohort (Oulu Project Elucidating Risk of Atherosclerosis, OPERA), initiated in 1991. The cohort consisted of 988 middle-aged Finnish participants. INTERVENTION: Total mortality and hospital events were followed up to 2009 based on the registry of the National Institute for Health and Welfare and the National death registry. MAIN OUTCOME MEASURE: The severity of hepatic steatosis was measured by ultrasound and divided into three groups (0-2). Cox regression analysis was used in the statistical analysis. RESULTS: In the follow-up of years 1991-2009, 13.5% of the participants with non-fatty liver, 24.2% of participants having moderate liver fat content and 29.2% of the participants having severe fatty liver experienced a cardiovascular event during the follow-up time (p<0.001). Severe liver fat content predicted the risk for future risk of cardiovascular event even when adjusted for age, gender and study group (HR 1.92, CI 1.32 to 2.80, p<0.01). When further adjustments for smoking, alcohol consumption, low-density lipoprotein-cholesterol, body mass index and systolic blood pressure were conducted, the risk still remained statistically significant (HR 1.74, CI 1.16 to 2.63, p<0.01). Statistical significance disappeared with further adjustment for QUICKI. CONCLUSIONS: Liver fat content increases the risk of future cardiovascular disease event in long-term follow-up but it is seems to be dependent on insulin sensitivity.

Metabolic syndrome in the prediction of cardiovascular events: the potential additive role of hsCRP and adiponectin.

BACKGROUND: Highly prevalent metabolic syndrome (MS) is a major public health problem worldwide. Insulin resistance and central obesity are postulated to be the key components of this metabolic syndrome, and inflammation also plays a role in cardiovascular events. In previous years, many definitions of metabolic syndrome have emerged. DESIGN AND METHODS: The value of MS as a predictor of cardiovascular events in median 18-year follow-up was studied in a prospective study cohort that included 1004 Finnish males and females. Cardiovascular disease included major coronary heart disease and stroke (excluding subarachnoid hemorrhage)-whichever of these happened first. RESULTS: Subjects with metabolic syndrome had a 2.01-fold (95% CI 1.46-2.77) higher probability for any cardiovascular event compared with subjects with no MS. hsCRP seemed to increase the risk prediction, whereas adiponectin was not helpful. Those having five components of MS had hazard ratios of 7.89 (2.26-27.60) for any cardiovascular event in the follow-up when compared with those having no components and adjusting by traditional risk factors (p < 0.01). CONCLUSIONS: MS is an important predictor of cardiovascular events and is most harmful in combination with high plasma hsCRP. The clustering of components is especially harmful.

Leptin receptor Arg109 homozygotes display decreased total mortality as well as lower incidence of cardiovascular disease and related death.

Two leptin receptor single nucleotide polymorphisms, Lys109Arg and Gln223Arg, have been shown to associate with several risk factors for cardiovascular disease. In addition, we have previously shown that Arg109 and Arg223 homozygotes displayed lower intima-media thickness in our well-defined OPERA (Oulu Project Elucidating Risk of Atherosclerosis) study. This current research investigated the impact of these LEPR polymorphisms on cardiovascular events and related death as well as to total mortality in the 19-year follow-up of OPERA. Subjects were randomly selected, middle-aged drug-treated hypertensives and their age- and sex-matched control subjects recruited to the OPERA study between 1990 and 1993. Mortality and hospital events of 1045 subjects were followed up until 2009. A total of 151 coronary heart disease (CHD) and 211 cardiovascular disease (CVD) events or deaths including 58 CHD and 69 CVD deaths occurred. Furthermore, during this follow-up, a total of 165 subjects died. Logistic regression analysis was performed to assess the impact of Lys109Arg and Gln223Arg on the events and death. Further modeling was performed with Cox regression for Lys109Arg. The logistic regression analysis revealed a significant protective impact of Arg109Arg genotype on CHD (OR 0.433; CI 95% 0.217-0.863) and CVD (OR 0.540; CI 95% 0.309-0.942) events or death as well as on total mortality (OR 0.390; CI 95% 0.196-0.775) when adjusted with age, sex and study group. Even after further adjustment with BMI, smoking status, systolic blood pressure and low-density lipoprotein cholesterol, the protective effect of Arg109Arg on CHD events or death and total mortality still remained statistically significant (OR 0.463; CI 95% 0.230-0.931 and OR 0.442; CI 95% 0.218-0.896, respectively). Arg109Arg was also shown to confer protection against CHD mortality (HR 0.224; CI95% 0.055-0.919) and overall mortality (HR 0.413; CI95% 0.218-0.783) also in Cox regression analysis. In conclusion, the Arg109Arg genotype of LEPR seems to be protective from cardiovascular events and death and this phenomenon seems to be independent of the traditional risk factors for atherosclerosis.

Long-term fructose feeding changes the expression of leptin receptors and autophagy genes in the adipose tissue and liver of male rats: a possible link to elevated triglycerides.

Long-term fructose consumption has been shown to evoke leptin resistance, to elevate triglyceride levels and to induce insulin resistance and hepatic steatosis. Autophagy has been suggested to function in processes such as lipid storage in adipose tissue and inflammation in liver. Autophagy and the leptin system have also been suggested to regulate each other. This study aimed to identify the changes caused by fetal undernourishment and postnatal fructose diet in the gene expression of leptin, its receptors (LEPR-a, LEPR-b, LEPR-c, LEPR-e and LEPR-f) and autophagy genes in the white adipose tissue (WAT) and liver of adult male rats in order to clarify the mechanism behind the metabolic alterations. The data clearly revealed that the long-term postnatal fructose diet decreased leptin levels (p < 0.001), LEPR (p < 0.001), especially LEPR-b (p = 0.011) and LEPR-f (p = 0.005), as well as SOCS3 (p < 0.001), ACC (p = 0.006), ATG7 (p < 0.001), MAP1LC3ß (p < 0.001) and LAMP2 (p = 0.004) mRNA expression in WAT. Furthermore, LEPR (p < 0.001), especially LEPR-b (p = 0.001) and LEPR-f (p < 0.001), ACC (p = 0.010), ATG7 (p = 0.024), MAP1LC3ß (p = 0.003) and LAMP2 (p < 0.001) mRNA expression in the liver was increased in fructose-fed rats. In addition, the LEPR expression in liver and MAP1LC3ß expression in WAT together explained 55.7 % of the variation in the plasma triglyceride levels of the rats (R adj. (2)  = 0.557, p < 0.001). These results, together with increased p62 levels in WAT (p < 0.001), could indicate decreased adipose tissue lipid storing capacity as well as alterations in liver metabolism which may represent a plausible mechanism through which fructose consumption could disturb lipid metabolism and result in elevated triglyceride levels.

Plasma lipid levels and body weight altered by intrauterine growth restriction and postnatal fructose diet in adult rats.

BACKGROUND: Intrauterine growth restriction (IUGR) is known to affect the risk of adult diseases. Consumption of lipogenic fructose is increasing, and it is used as an enhancer of metabolic syndrome in rat experiments. The effects of IUGR, postnatal fructose diet, and their interaction on the lipid profile and adiposity were studied in adult rats. METHODS: IUGR was induced by providing pregnant rats with 50% of daily food intake. From 1 mo onward, half of the offspring received a fructose-rich diet and were then followed to the age of 1 and 6 mo, when plasma lipid, glucose, and insulin levels were measured. The adipose tissue was visualized by magnetic resonance imaging at the age of 6 mo. RESULTS: IUGR and fructose diet decreased body weight in adult rats. IUGR increased low-density lipoprotein cholesterol in 6-mo-old rats. The fructose diet evoked hypertriglyceridemia and hyperinsulinemia in both the sexes and decreased fasting glucose levels in female rats. Postnatal fructose diet increased lipid content percentage in the retroperitoneal and intra-abdominal adipose tissues in male rats. Interactions between IUGR and postnatal fructose diet were observed in adult weight in males. CONCLUSION: These results demonstrate the importance of IUGR and fructose diet in adverse changes in lipid and glucose metabolism.

Long telomeres in blood leukocytes are associated with a high risk of ascending aortic aneurysm.

Ascending aortic aneurysm is a connective tissue disorder. Even though multiple novel gene mutations have been identified, risk profiling and diagnosis before rupture still represent a challenge. There are studies demonstrating shorter telomere lengths in the blood leukocytes of abdominal aortic aneurysm patients. The aim of this study was to measure whether relative telomere lengths are changed in the blood leukocytes of ascending aortic aneurysm patients. We also studied the expression of telomerase in aortic tissue samples of ascending aortic aneurysms. Relative lengths of leukocyte telomeres were determined from blood samples of patients with ascending aortic aneurysms and compared with healthy controls. Telomerase expression, both at the level of mRNA and protein, was quantified from the aortic tissue samples. Mean relative telomere length was significantly longer in ascending aortic aneurysm blood samples compared with controls (T/S ratio 0.87 vs. 0.61, p<0.001). Expressions of telomerase mRNA and protein were elevated in the aortic aneurysm samples (p<0.05 and p<0.01). Our study reveals a significant difference in the mean length of blood leukocyte telomeres in ascending aortic aneurysm and controls. Furthermore, expression of telomerase, the main compensating factor for telomere loss, is elevated at both the mRNA and protein level in the samples of aneurysmal aorta. Further studies will be needed to confirm if this change in telomere length can serve as a tool for assessing the risk of ascending aortic aneurysm.

Adiponectin concentration in plasma is associated with muscle fiber size in healthy middle-aged men.

Obesity and ectopic fat deposition are major risk factors for many diseases ranging from insulin resistance to type 2 diabetes and atherosclerosis. In obese individuals, the size of muscle fibers is increased mainly because of the ectopic fat present in skeletal muscle. The aim of the study was to investigate if adipokines would associate with muscle fiber characteristics and if muscle fiber characteristics and expression of the skeletal muscle adiponectin receptor (ADIPOR) would be associated with overweight and other components of the metabolic syndrome. This is a population-based, epidemiological cross-sectional study where normotensive, non-smoking men with normal OGTT provided a muscle biopsy (N = 54). Body mass index was higher in the group with the largest muscle fiber size (p for trend < 0.05) compared to medium (p < 0.05) or small (p < 0.05) muscle fiber size. Plasma adiponectin level (p < 0.05) was negatively and concentrations of leptin (p < 0.05) and hs-CRP (p < 0.05) positively associated with muscle fiber size before adjustments. The inverse association between the plasma adiponectin level and muscle fiber size tertile remained significant (p < 0.05) when adjusted for age and total adiposity. No associations were observed between the expression of muscle adiponectin receptors (ADIPOR) and features of the metabolic syndrome. Skeletal muscle fiber characteristics are related to overweight. In addition, a correlation was observed between low adiponectin and large muscle fiber size and this was not dependent on the amount of total fatness.

Plasma adiponectin--an independent indicator of liver fat accumulation.

Proinflammatory cytokines and adipokines have a significant role in the development and progression of fatty liver. The aim of our current study was to explore the major indicators for hepatic fat determined as liver brightness. In addition to peptide hormones, several known cardiovascular and metabolic risk factors were included in the model. This is a population-based, epidemiological, cross-sectional study where 1200 subjects (600 men and 600 women, aged 40-59 years) were randomly selected, half of them having hypertension and half of them being controls. The severity of liver adiposity was measured by ultrasound and based on the brightness of the liver estimated as a numerical value ranging from 0 to 2. With respect to the studied peptide hormones, the associations between liver brightness and plasma adiponectin (P < .001), leptin (P < .001), ghrelin (P = .005), and highly sensitive C-reactive protein concentrations (P < .001) were significant before adjustments. When several other risk factors (age, sex, body mass index, waist circumference, quantitative insulin sensitivity check index, smoking, and alcohol consumption) and novel risk markers (adiponectin, leptin, ghrelin, and highly sensitive C-reactive protein concentrations) were considered simultaneously, of the peptide hormones, adiponectin remained the strongest independent indicator of the brightness of the liver (P = .025). Adiponectin is a very strong predictor for liver brightness, even after adjustment for the numerous other metabolic risk factors, markers of inflammation, and novel obesity-related peptide hormones. Whether low adiponectin levels predict to liver fat accumulation remains to be explored in a future prospective follow-up of this cohort.

Adiponectin induced placental cell apoptosis could be mediated via the ADIPOR1-receptor in pre-eclampsia with IUGR.

AIMS: Adiponectin and leptin are members of the adipocytokine family. Adiponectin promotes and leptin inhibits apoptosis and both are regulators of angiogenesis. Adipocytokines and their receptors are expressed in the placenta, and in the pre-eclamptic (PE) mother the serum levels of both are higher than in healthy ones. Our aim was to study the expression of adiponectin, leptin, their receptor genes and apoptosis in severely PE and normal placentas. METHODS: The study group comprised 13 PE mothers and their 16 healthy controls. Placental biopsies were taken during cesarean section, the RNA was extracted and micro-array study was performed, followed by PCR and apoptosis studies. RESULTS: The placental expression level of the leptin and adiponectin receptor 1 genes was significantly higher in PE mothers than in controls. No significant changes were observed in the levels of the adiponectin, adiponectin receptor 2 and Leptin receptor genes. The expression of the Adiponectin gene was low. The rate of apoptosis was higher in the PE placentas. CONCLUSIONS: The activity of placental adipocytokines and their receptor genes in severe PE may suggest an important role in placental angiogenesis. Placental apoptosis induced by adiponectin could be mediated via the ADIPOR1-receptor.

The effect of energy restriction during pregnancy on obesity-related peptide hormones in rat offspring.

It has been proposed that fetal exposure to environmental stressors, such as undernutrition, during critical periods of development may lead to adaptations that permanently change the structure and function of the body. These adaptations may be important for immediate survival during fetal development, but can predispose to disease in later life. We designed a pilot study investigating the effect of fetal undernutrition on the obesity-related peptides adiponectin, ghrelin, leptin and resistin levels in rat. We also wanted to explore changes in lipid and insulin metabolism. Sprague-Dawley rats were randomly assigned to three dietary treatment groups on day 4 of gestation. The control group was fed ad libitum and the food-restricted rats received either 75% or 50% of ad libitum food intake until parturition. Serum levels of obesity-related peptides as well as lipid and insulin levels were measured from 1-month-old pups. Serum resistin concentrations were higher in both food-restricted groups and serum adiponectin concentration was lower in the 50% food-restricted group compared to the control group. Serum total cholesterol levels were significantly higher in both food-restricted groups. These results indicate that undernutrition during fetal development may lead to unfavorable changes in obesity-related peptide hormones as well as evoking adverse changes in serum cholesterol levels. The observed changes may predispose to insulin resistance and significantly increase the risk of developing cardiovascular disease in later life.

Gene expression profiles in fetal and neonatal rat offspring of energy-restricted dams.

BACKGROUND/AIMS: Nutrition during fetal and early postnatal development can have permanent effects on physiology resulting in an increased risk for disease in later life. The aim of this study was to explore changes in gene expression related to maternal energy restriction during pregnancy in rat fetuses and in neonatal rat offspring. METHODS: From day 4 of gestation until parturition, energy-restricted dams received either 75 or 50% of ad libitum food intake. Microarray analyses were performed on whole 13- and 17-day fetuses and 1-day-old pups. Protein and fat contents of the dams' milk were analyzed in the different feeding groups. RESULTS: A surprisingly small number of genes were differentially expressed between the groups, probably due to the strict control of fetal development. Interestingly, the expressions of many pancreatic digestion enzymes were reduced in the 1-day-old pups of the energy-restricted dams. A statistically significant difference in milk protein content was observed on day 1 post-partum between the gestationally food-restricted groups. CONCLUSIONS: The expressions of several genes that may have an important role in the normal development of organs were affected by undernutrition during fetal development. In addition, undernutrition may have affected the function of the exocrine pancreas.

Estrogen replacement therapy decreases plasma adiponectin but not resistin in postmenopausal women.

The effects of estrogen replacement therapy (ERT) to cardiovascular disease risk are still unclear. Low adiponectin and high resistin plasma concentrations are reported to be associated with atherosclerosis. However, it is not known how ERT affects plasma adiponectin and resistin concentrations. Seventy-three hysterectomized, nondiabetic, postmenopausal women were randomized in a double-blind, double-dummy study to receive either peroral estradiol valerate or transdermal 17beta-estradiol gel for 6 months. Biochemical measurements were determined from samples taken before and after the therapy. Peroral estradiol valerate therapy decreased adiponectin concentrations from 13.6 to 11.6 mg/L (P = .008), whereas transdermal 17beta-estradiol gel had no effect (12.7 vs 12.2 mg/L). Neither treatment changed the resistin concentrations significantly. Plasma concentrations of estradiol and estrone did not correlate with adiponectin or resistin concentrations before or after therapy. The change in adiponectin concentration correlated significantly with the changes in waist-hip ratio, very low-density lipoprotein triglycerides, and insulin-like growth factor 1 in the peroral estradiol valerate group. The changes in these variables and the change in estradiol concentration explained 43.1% (P = .001) of the variability in the change of plasma adiponectin, the change in very low-density lipoprotein triglycerides being the strongest determinant (beta = -.407, P = .011). The results show that peroral ERT can decrease plasma adiponectin levels. However, ERT does not seem to influence plasma resistin concentrations.

Low serum adiponectin level as a predictor of impaired glucose regulation and type 2 diabetes mellitus in a middle-aged Finnish population.

Low levels of adiponectin are associated with obesity and type 2 diabetes mellitus (DM2). However, only few studies on this topic have used the most recent World Health Organization 1999 criteria, which include a definition of impaired glucose regulation (IGR). Our objective was to find out if a baseline low adiponectin level in initially normoglycemic subjects predicted IGR or DM2 during a mean follow-up period of 5.1 years. A population-based cohort study was carried out in Oulu, Northern Finland. Subjects born in 1935 and living in Oulu in 1990 were invited to participate in a follow-up study. At baseline, oral glucose tolerance tests and measurements of adiponectin, lipids, blood pressure, and body mass index were performed; and oral glucose tolerance tests were repeated at follow-up. Analyses were performed for 201 subjects who were normoglycemic at baseline. Low adiponectin level was defined as the lowest quartile of adiponectin levels. During the follow-up, 47 (23%) of the 201 subjects developed IGR or DM2. Impaired glucose regulation or DM2 developed in 15 of 41 (37%) subjects with low adiponectin level at baseline, whereas the corresponding proportion was 32 of 160 (20%) subjects with higher adiponectin levels (P = .025). In logistic regression analysis, the adjusted odds ratio for IGR or DM2 was 2.1 (95% confidence interval, 1.0-4.5) when adjustment was made for sex and body mass index. Low concentrations of adiponectin predicted subsequent development of IGR and DM2 in initially normoglycemic middle-aged Finnish subjects. Our findings support the hypothesis that adiponectin may play a role in the pathogenesis of abnormal glucose metabolism.

Low plasma adiponectin concentration is an indicator of the metabolic syndrome.

OBJECTIVE: Adiponectin is an adipocytokine known to be decreased in obesity. It functions in glucose and fatty acid metabolism and also has an anti-inflammatory role in microvasculature. We wanted to investigate the role of adiponectin as a biomarker of metabolic syndrome (MS) and see how the plasma adiponectin levels relate to new criteria of MS proposed by the International Diabetes Federation. METHODS: Plasma adiponectin concentrations were measured from total of 1041 Finnish subjects with an ELISA - a novel method planned in our laboratory. RESULTS: In both the sexes, the plasma adiponectin levels were lower in subjects with MS when compared with subjects with no diagnosis of MS (P< 0.001). Plasma adiponectin levels did not differ between subjects with National Cholesterol Education Program (ATPIII) and International Diabetes Federation-defined MS. Lower adiponectin levels were associated with different components of the MS and there was a trend towards decreasing adiponectin levels with an increasing number of components of MS in both the sexes. Subjects in the lowest adiponectin quartile had a significantly higher probability of having MS (P< 0.001), 4.4-fold in males and 7.5-fold in females, when compared with the corresponding individuals in the highest quartile. The probability increased in every lowering quartile of adiponectin level and was independent of body mass index. CONCLUSION: We conclude that adiponectin levels correlate with most of the components of the MS and the metabolic cluster per se.

Adiponectin polymorphisms, adiposity and insulin metabolism: HERITAGE family study and Oulu diabetic study.

AIMS/HYPOTHESIS: Adiponectin is an adipocytokine with lowered blood levels in obesity and Type 2 diabetes mellitus. We sought to define the specific effects of different alleles of the gene encoding adiponectin. METHODS: We studied the associations of adiponectin gene sequence variations with body fat distribution and insulin indices in 503 White and 276 Black subjects of the HERITAGE Family Study cohort and subjects from a Finnish population. RESULTS: The His111 allele frequency of the Tyr111 His polymorphism in Finnish Type 2 diabetic subjects (n=254) was higher (5.1%) than in control subjects (n=270) (2.6%; P = 0.033). In the HERITAGE cohort, the His111 allele was associated with a lower insulin sensitivity index (P = 0.018) and a higher acute insulin response to glucose (P = 0.0098) in Whites. Other variants showed associations with adiposity and plasma lipid values only in Blacks. Among Blacks, the IVS2+G62T variant was associated with body fat (P = 0.002) and total cholesterol values (P = 0.005), and the Gly15Gly variant with cholesterol (P = 0.009) and triglyceride (P = 0.05) levels. The haplotype derived from these two polymorphisms was associated with total body fat, while the IVS2+G62T and Tyr111His-haplotype was associated with body fat and disposition index. CONCLUSIONS: The carriers of the His111 allele may have a higher risk of developing Type 2 diabetes mellitus. Racial differences were found between Blacks and Whites in body composition and lipids according to ACDC genotypes. Sequence variants in the adiponectin gene appear to be associated with diabetes and diabetes-related phenotypes.

Adiponectin: a link between excess adiposity and associated comorbidities?

Adiponectin is a novel polypeptide that is highly specific to adipose tissue. In contrast to other adipocytokines, adiponectin levels are decreased in obesity and associated comorbidities, such as type 2 diabetes. Decreased expression of adiponectin is correlated with insulin resistance. It has been suggested that several agents, such as tumor necrosis factor alpha, could mediate their effects on insulin metabolism through modulating adiponectin secretion from adipocytes. The mechanisms for the development of atherosclerotic vascular disease in obese individuals are largely unknown. Several findings support the interesting hypothesis that adiponectin could be a link between obesity and related atherosclerosis. First, adiponectin levels are lower in patients with coronary artery disease. Second, adiponectin modulates endothelial function and has an inhibitory effect on vascular smooth muscle cell proliferation. Moreover, adiponectin is accumulated more preferably to the injured vascular wall than intact vessels and has been shown to suppress macrophage-to-foam cell transformation. Adiponectin may also be involved in the modulation of inflammation. Thiazolidinediones, antiatherogenic and other effects have been explained by their direct enhancing effect on adiponectin. In conclusion, adiponectin has anti-inflammatory and antiatherogeneic effects as well as multiple beneficial effects on metabolism. Therefore it is not a surprise that adiponectin therapy has been tested in animal models of obesity, and it has been shown to ameliorate hyperglycemia and hyperinsulinemia without inducing weight gain or even inducing weight loss in some studies. Unlike agents that exert their effects centrally, adiponectin's effects seem to be peripherally mediated. The evidence of an association between adiponectin and the metabolic and cardiovascular complications of obesity is growing all the time.