Low plasma adiponectin levels are associated with increased hepatic lipase activity in vivo

Sex-Related Differences in the Associations between Adiponectin and Serum Lipoproteins in Healthy Subjects and Patients with Metabolic Syndrome

The strong associations between the serum levels of adiponectin and the lipoprotein subclasses observed in healthy subjects are much weaker in patients with metabolic syndrome (MS). However, the impact of sex on these associations remained unexplored. Therefore, in the present study, we examined associations between adiponectin and the lipoprotein subclasses, analyzed by nuclear magnetic resonance spectroscopy, separately in healthy females and males, as well as in females and males with MS. We observed negative correlations between adiponectin and VLDL, IDL, and small-dense LDL in healthy males, but neither in healthy females nor in females or males with MS. Additionally, adiponectin was positively correlated with some HDL subclasses in healthy males and females with MS, but not in healthy females or males with MS. Adjusting for age and either body mass index, waist circumference, C-reactive protein, or interleukin-6 weakened the associations between adiponectin and VLDL and IDL but not small-dense LDL. The adjustment weakened the associations between adiponectin and HDL in healthy males but not in females with MS. Based on our results, we conclude that sex and the presence of MS are strong determinants of the associations between adiponectin and serum lipoproteins and that the complex regulatory network comprising adiponectin and other molecular players involved in the regulation of lipoprotein metabolism is primarily operative in healthy males and females with MS.

Serum Levels of Adiponectin Are Strongly Associated with Lipoprotein Subclasses in Healthy Volunteers but Not in Patients with Metabolic Syndrome

Metabolic syndrome (MS) is a widespread disease in developed countries, accompanied, among others, by decreased adiponectin serum levels and perturbed lipoprotein metabolism. The associations between the serum levels of adiponectin and lipoproteins have been extensively studied in the past under healthy conditions, yet it remains unexplored whether the observed associations also exist in patients with MS. Therefore, in the present study, we analyzed the serum levels of lipoprotein subclasses using nuclear magnetic resonance spectroscopy and examined their associations with the serum levels of adiponectin in patients with MS in comparison with healthy volunteers (HVs). In the HVs, the serum levels of adiponectin were significantly negatively correlated with the serum levels of large buoyant-, very-low-density lipoprotein, and intermediate-density lipoprotein, as well as small dense low-density lipoprotein (LDL) and significantly positively correlated with large buoyant high-density lipoprotein (HDL). In patients with MS, however, adiponectin was only significantly correlated with the serum levels of phospholipids in total HDL and large buoyant LDL. As revealed through logistic regression and orthogonal partial least-squares discriminant analyses, high adiponectin serum levels were associated with low levels of small dense LDL and high levels of large buoyant HDL in the HVs as well as high levels of large buoyant LDL and total HDL in patients with MS. We conclude that the presence of MS weakens or abolishes the strong associations between adiponectin and the lipoprotein parameters observed in HVs and disturbs the complex interplay between adiponectin and lipoprotein metabolism.

Relationship between circulating adipokines and cholesterol efflux in subjects with severe carotid atherosclerosis

AIMS

Cholesterol efflux capacity (CEC) as a measure of high-density lipoprotein functionality is independently and inversely associated with increased risk of cardiovascular events and mortality, and advanced plaque morphology. Adipokines, adipose tissue-derived factors, can influence systemic lipoprotein metabolism, and participate in the regulation of vascular function and inflammation. We aimed to investigate the association between CEC and circulating adipokine levels (anti-inflammatory adiponectin, and pro-inflammatory chemerin and resistin) in subjects with severe carotid atherosclerotic disease and evaluate its impact on post-surgical outcomes.

METHODS AND RESULTS

This is a cross-sectional study with a 5-year follow-up component. Consecutive patients with severe carotid atherosclerosis scheduled for a carotid endarterectomy were recruited from hospital-based centres in Montreal, Canada (n = 285). Fasting blood samples were collected pre-operatively and used to measure plasma total and high-molecular weight (HMW) adiponectin, chemerin, and resistin, and to perform cholesterol efflux assays in J774 macrophage-like cells. Five-year post-surgery outcomes were obtained through medical chart review. Subjects had a mean age of 70.1 ± 9.4, were 67.0 % male, had various comorbidities (hypercholesterolemia [85.3 %], hypertension [83.5 %], type 2 diabetes [34.5 %], coronary artery disease [38.6 %]), and previously experienced cerebrovascular symptomatology (77.9 %). CEC was independently and positively associated with total and HMW adiponectin levels (ß [95 % confidence interval]; 0.216 [0.134-0.298] and 0.107 [0.037-0.176], respectively) but not with chemerin or resistin. Total adiponectin had the greatest association accounting for 8.3 % of the variance in CEC. Interaction regression models demonstrated a significant interaction between adiponectin and chemerin in increasing CEC. Notably, with each unit increase in CEC there was a 93.9 % decrease in the odds of having an ischemic cerebrovascular event 5 years post-surgery (0.061 [0.007-0.561]).

CONCLUSIONS

Our findings demonstrated circulating adiponectin to have a strong association with increased CEC in subjects with severe carotid atherosclerosis and high CEC to be associated with more favourable post-surgical outcomes. These findings reflect the importance of adipose tissue health in influencing CEC levels and atherosclerotic cardiovascular disease risk.

Relationships of adiponectin to regional adiposity, insulin sensitivity, serum lipids, and inflammatory markers in sedentary and endurance-trained Japanese young women

INTRODUCTION

This study aims to compare the differences in circulating adiponectin levels and their relationships to regional adiposity, insulin resistance, serum lipid, and inflammatory factors in young, healthy Japanese women with different physical activity statuses.

METHODS

Adipokines (adiponectin and leptin), full serum lipid, and inflammatory factors [white blood cell counts, C-reactive protein, tumor necrosis factor-α, tissue plasminogen activator inhibitor-1 (PAI-1)] were measured in 101 sedentary and 100 endurance-trained healthy Japanese women (aged 18-23 years). Insulin sensitivity was obtained through a quantitative insulin-sensitivity check index (QUICKI). Regional adiposity [trunk fat mass (TFM), lower-body fat mass (LFM), and arm fat mass (AFM)] was evaluated using the dual-energy X-ray absorptiometry method.

RESULTS

No significant difference was observed between the sedentary and trained women in terms of adiponectin levels. The LFM-to-TFM ratio and the high-density lipoprotein cholesterol (HDL-C) were the strong positive determinants for adiponectin in both groups. Triglyceride in the sedentary women was closely and negatively associated with adiponectin, as well as PAI-1 in the trained women. The QUICKI level was higher in the trained than sedentary women. However, no significant correlation between adiponectin and insulin sensitivity was detected in both groups. Furthermore, LFM was associated with a favorable lipid profile against cardiovascular diseases (CVDs) in the whole study cohort, but this association became insignificant when adiponectin was taken into account.

CONCLUSIONS

These findings suggest that adiponectin is primarily associated with regional adiposity and HDL-C regardless of insulin sensitivity and physical activity status in young, healthy women. The associations among adiponectin, lipid, and inflammatory factors are likely different in women with different physical activity statuses. The correlation of LFM and a favorable lipid profile against CVD and adiponectin is likely involved in this association.

Brown adipose tissue influences adiponectin and thyroid hormone changes during Graves' disease therapy

Thyroid hormones (TH), adiponectin and brown adipose tissue (BAT) are regulators of energy homoeostasis. Influence of BAT activity on the relationship between TH and adiponectin remains unexplored. The aim of the study was to identify the relationship between TH and adiponectin and to clarify the impact of active BAT on the metabolic effects of adiponectin before and after the correction of thyrotoxicosis. Twenty-one patients with newly diagnosed hyperthyroidism from Graves' disease were recruited. A titration dosing regimen of thionamide anti-thyroid drug (ATD) was used to establish euthyroidism over 12-24 weeks. Anthropometric, biochemical and adipocytokine parameters were measured before and after control of hyperthyroidism. BAT activity was quantified by fusion 18 F-fluorodeoxyglucose (18 F-FDG) PET/MR imaging, and patients were grouped based on BAT status. Plasma adiponectin level was significantly increased following correction of hyperthyroidism in the overall sample. Free thyroxine (FT4) was also identified as a predictor of adiponectin level in thyroid dysfunction. However, significant changes in adiponectin level and correlations involving adiponectin were absent in BAT-positive patients but maintained in BAT-negative patients. BAT activity diminishes the correlative relationship with body composition and abolishes TH and adiponectin relationships when transitioning from a hyperthyroid to euthyroid state.

Association of Serum Adiponectin Biomarker with Metabolic Syndrome Components in Koreans with Extremely High HDL Cholesterol Levels in General Health Checkup

Adiponectin and high-density lipoprotein cholesterol (HDL-C) are negative predictors for cardio-metabolic disorders. This study explored adiponectin's role in predicting multiple metabolic syndrome components (multi-MetSC) in subjects with extremely high HDL-C levels overall and by sex. We enrolled adults with extremely high HDL-C levels (≥90 mg/dL) in general health checkups and compared adiponectin levels in subjects with and without multi-MetSC. Among 274 subjects (median 44 years, female 79.6%), 19 (6.9%) had a multi-MetSC. The adiponectin level was significantly lower in subjects with multi-MetSC than without (females: 9.2 [6.2-13.3] vs. 12.0 [9.7-15.9] µg/mL, p = 0.039; males: 6.9 ± 2.4 vs. 10.0 ± 5.2 µg/mL, p = 0.013). The optimal cutoff values to predict multi-MetSC were 9.7 µg/mL (sensitivity 64%, specificity 74%) in females and 9.6 µg/mL (sensitivity 100%, specificity 44%) in males. Compared with the high adiponectin group, the low group revealed higher fasting glucose in females and higher waist circumference, visceral fat area, and HDL-C levels in males. Multiple logistic regression analysis confirmed adiponectin as an independent predictor of multi-MetSC (OR 0.85, 95% CI 0.71-0.97). Adiponectin could be a potential biomarker for multi-MetSC in general health checkup subjects with extremely high HDL-C levels. There were sex differences in the metabolic risk factors between low and high adiponectin groups.

Associations of Abdominal and Cardiovascular Adipose Tissue Depots With HDL Metrics in Midlife Women: the SWAN Study

CONTEXT

The menopause transition is accompanied by declines in the atheroprotective features of high-density lipoprotein (HDL), which are linked to deleterious cardiovascular (CV) outcomes.

OBJECTIVE

This work aimed to assess the relationship between abdominal and CV visceral adipose tissues (VAT) with future HDL metrics in midlife women, and the role of insulin resistance (IR) on these associations.

METHODS

Temporal associations compared abdominal and CV fat with later measures of HDL metrics. This community-based cohort comprised 299 women, baseline mean age 51.1 years (SD: 2.8 years), 67% White, 33% Black, from the Study of Women's Health Across the Nation (SWAN) HDL ancillary study. Exposures included volumes of abdominal VAT, epicardial AT (EAT), paracardial AT (PAT), or perivascular AT (PVAT). Main outcomes included HDL cholesterol efflux capacity (HDL-CEC); HDL phospholipids (HDL-PL), triglycerides (HDL-Tgs), and cholesterol (HDL-C); apolipoprotein A-I (ApoA-I), and HDL particles (HDL-P) and size.

RESULTS

In multivariable models, higher abdominal VAT was associated with lower HDL-CEC, HDL-PL, HDL-C, and large HDL-P and smaller HDL size. Higher PAT was associated with lower HDL-PL, HDL-C, and large HDL-P and smaller HDL size. Higher EAT was associated with higher small HDL-P. Higher PVAT volume was associated with lower HDL-CEC. The Homeostatic Model Assessment of Insulin Resistance partially mediated the associations between abdominal AT depots with HDL-CEC, HDL-C, large HDL-P, and HDL size; between PVAT with HDL-CEC; and PAT with HDL-C, large HDL-P, and HDL size.

CONCLUSION

In midlife women, higher VAT volumes predict HDL metrics 2 years later in life, possibly linking them to future CV disease. Managing IR may preclude the unfavorable effect of visceral fat on HDL metrics.

Adiponectin Concentration and Chronic Stroke Individuals, Associations with Body Composition, Physical Activity Levels and Lipid Profile: A Cross-Sectional Explorative Study

OBJECTIVE

Higher adiponectin concentration has been associated with the presence of sarcopenia in individuals with cardiovascular diseases. Post-stroke individuals presented higher adiponectin concentrations than non-stroke ones. However, no previous study has investigated the association between the adiponectin concentration and skeletal muscle mass in post-stroke individuals. On the other hand, higher adiponectin concentration has been associated with a more favorable lipid profile and the physical activity level might regulate adiponectin concentration. These associations have not been studied in this population. Thus, the main objective of this study was to determine whether the adiponectin concentration is associated with: (1) body composition; (2) lipid profile; and (3) physical activity level in chronic post-stroke individuals.

MATERIALS AND METHODS

This study was a correlational, cross-sectional exploratory study. Data on body composition and lipid profile were collected using a bioelectrical impedance analyzer (InBody® 720) and an automated method analyzer (CELL-DYN Ruby), respectively. The physical activity level was measured by the StepWatch® Activity Monitor and the serum adiponectin concentration was analyzed using an enzyme-linked immunosorbent assay kit. Correlation analyses were made using Spearman's rank correlation coefficient (r_s).

RESULTS

Twenty-one post-stroke participants took part in the study. The adiponectin concentration was associated with the following: skeletal muscle mass (r_s = -0.78), skeletal muscle mass index (r_s = -0.75) and high-density lipoprotein (r_s = 0.43).

CONCLUSIONS

A greater adiponectin concentration is associated with a lower skeletal muscle mass and a higher high-density lipoprotein level in chronic post-stroke individuals, but not with physical activity levels.

Obesity Affects HDL Metabolism, Composition and Subclass Distribution

Background: Obesity increases the risk of coronary heart disease, partly due to its strong association with atherogenic dyslipidemia, characterized by high triglycerides and low high-density lipoprotein (HDL) cholesterol levels. Functional impairment of HDL may contribute to the increased cardiovascular mortality, but the effect of obesity on composition, structure, and function of HDL is not well understood. Design and Methods: We determined HDL composition, HDL subclass distribution, parameters of HDL function, and activities of most important enzymes involved in lipoprotein remodeling, including lecithin–cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) in relatively young normal weight (n = 26), overweight (n = 22), and obese (n = 20) women. Results: Obesity (body mass index (BMI) ≥ 30) was associated with noticeable changes in LCAT and CETP activities and altered HDL composition, such as decreased apolipoprotein A-I, cholesterol, and phospholipid content, while pro-inflammatory HDL serum amyloid a content was increased. We observed a marked shift towards smaller HDL subclasses in obesity linked to lower anti-oxidative capacity of serum. LCAT activity, HDL subclass distribution, and HDL-cholesterol were associated with soluble leptin receptor, adiponectin, and liver enzyme activities. Of note, most of these alterations were only seen in obese women but not in overweight women. Conclusions: Obesity markedly affects HDL metabolism, composition, and subclass distribution linked to changes in liver and adipose tissue. HDL dysfunction may contribute to increased cardiovascular risk in obesity.

Biomarkers of cardiometabolic complications in survivors of childhood acute lymphoblastic leukemia

Survivors of childhood acute lymphoblastic leukemia (cALL) are at higher risk of developing cardiometabolic complications. We aimed at exploring the associations between biomarkers of inflammation, oxidative stress, endothelial function, endotoxemia and cardiometabolic risk factors. We conducted a cross-sectional analysis in 246 cALL survivors (mean age, 22.1 ± 6.3 years; mean time since diagnosis, 15.5 ± 5.2 years) and evaluated the associations using a series of logistic regressions. Using structural equation models, we also tested if the relationship between endotoxemia and cardiometabolic complications was mediated by the latent (unobserved) variable inflammation inferred from the observed biomarkers CRP, TNF-α and IL-6. High leptin-adiponectin ratio was associated with obesity [adjusted OR = 15.7; 95% CI (6.2–39.7)], insulin resistance [20.6 (5.2–82.1)] and the metabolic syndrome [11.2 (2.6–48.7)]. Higher levels of plasminogen activator inhibitor-1 and tumor necrosis factor-α were associated with obesity [3.37 (1.6–7.1) and 2.34 (1.3–4.2), respectively] whereas high C-reactive protein levels were associated with insulin resistance [3.3 (1.6–6.8)], dyslipidemia [2.6 (1.4–4.9)] and MetS [6.5 (2.4–17.9)]. Our analyses provided evidence for a directional relationship between lipopolysaccharide binding protein, related to metabolic endotoxemia, inflammation and cardiometabolic outcomes. Identification of biomarkers and biological mechanisms could open new avenues for prevention strategies to minimize the long-term sequelae, improve follow-up and optimize the quality of life of this high-risk population.

Effects of dietary dihydroartemisinin supplementation on growth performance, hepatic inflammation, and lipid metabolism in weaned piglets with intrauterine growth retardation

The aims of this study were to investigate the effects of dietary supplementation with dihydroartemisinin (DHA) on growth performance, hepatic inflammation, and lipid metabolism in intrauterine growth retardation (IUGR)-affected weaned piglets. Eight piglets with normal birth weight (NBW) and 16 IUGR-affected piglets were selected and fed either a basal diet (NBW and IUGR groups) or the basal diet supplemented with 80 mg/kg DHA (IUGR-DHA group) from 21 to 49 day of age. Blood and liver samples were collected on day 49. DHA supplementation significantly alleviated the compromised growth performance and liver damage in IUGR-affected piglets. Additionally, DHA supplementation decreased the activities of alanine aminotransferase and aspartate aminotransferase, as well as the serum levels of non-esterified fatty acids (NEFA), very-low-density lipoprotein, and total cholesterol. In the liver, the concentrations of interleukin 1 beta, interleukin 6, tumor necrosis factor alpha, triglycerides, and NEFA were decreased. Fatty acid synthesis was decreased by DHA supplementation, whereas the activities of lipoprotein lipase, hepatic lipase, and total lipase were increased. Dietary DHA supplementation led to upregulation of the expression of AMPK/SIRT1 signaling pathway-related genes, whereas that of inflammatory factor-related genes were downregulated. In conclusion, dietary inclusion of 80 mg/kg DHA can alleviate IUGR-induced impairments in piglets.

Age-Related Changes in Serum Lipid Levels, Hepatic Morphology, Antioxidant Status, Lipid Metabolism Related Gene Expression and Enzyme Activities of Domestic Pigeon Squabs (Columba livia)

The objective of this study was to evaluate the age-related changes in antioxidant status and the lipid metabolism of pigeon squabs (Columba livia), by determining the BW, antioxidant indices, serum lipid levels, lipid metabolism-related enzyme activities, lipid metabolism-related gene expression, and liver morphology in squabs. Ten squabs were randomly selected and sampled on the day of hatching (DOH), days 7 (D7), 14 (D14) and 21 (D21) post-hatch, respectively. The results showed that BW of squabs increased linearly from DOH to D21. The minimum fold of BW gain was observed in the phase from D14 to D21. Serum triglyceride and free fatty acid levels displayed linear and quadratic trends as age increased, with these maximum responses in D14. Serum low-density lipoprotein cholesterol level responded to age linearly and quadratically with the minimum in D14. Serum high-density lipoprotein cholesterol level and the ratio of high-density lipoprotein cholesterol to low-density lipoprotein cholesterol increased linearly with age, whereas the very low-density lipoprotein cholesterol level decreased linearly. The activities of glutathione peroxidase, catalase, and superoxide dismutase in liver displayed linear and quadratic trends as age increased, with these minimum responses in D14. Hepatic malondialdehyde concentration responded to age linearly and quadratically, with the maximum in D14. Activities of lipoprotein lipase, hepatic lipase, and 3-hydroxy-3-methyl glutaryl coenzyme A reductase in liver responded to age linearly and quadratically, with these minimum responses in D14. Hepatic hormone-sensitive lipase activity displayed linear and quadratic trends as age increased with the maximum in D14. Hepatic acetyl CoA carboxylase activity on D14 was significantly lower than squabs on DOH and D7. Hepatic carnitine palmitoyltransferase 1 mRNA expression responded to age linearly and quadratically, with minimum response in D14. Hepatic mRNA expression of acetyl CoA carboxylase and fatty acid synthetase increased linearly with age. Hepatic Oil-Red-O staining area displayed a quadratic trend as age increased, with the maximum response in D14. In conclusion, the phase from DOH to D14 was a crucial development stage for growth, antioxidant status and lipid metabolism in pigeon squabs. The results suggest it is better to take nutritional manipulation in squabs before D14.

Links Between Adiponectin and Dementia: From Risk Factors to Pathophysiology

With the aging population, dementia is becoming one of the most serious and troublesome global public health issues. Numerous studies have been seeking for effective strategies to delay or block its progression, but with little success. In recent years, adiponectin (APN) as one of the most abundant and multifunctional adipocytokines related to anti-inflammation, regulating glycogen metabolism and inhibiting insulin resistance (IR) and anti-atherosclerosis, has attracted widespread attention. In this article, we summarize recent studies that have contributed to a better understanding of the extent to which APN influences the risks of developing dementia as well as its pathophysiological progression. In addition, some controversial results interlinked with its effects on cognitive dysfunction diseases will be critically discussed. Ultimately, we aim to gain a novel insight into the pleiotropic effects of APN levels in circulation and suggest potential therapeutic target and future research strategies.

The role of adiponectin in cholesterol efflux and HDL biogenesis and metabolism

Cholesterol efflux is the initial step in the reverse cholesterol transport pathway by which excess cholesterol in peripheral cells is exported and subsequently packaged into high-density lipoprotein (HDL) particles. Adiponectin is the most abundantly secreted adipokine that possesses anti-inflammatory and vasculoprotective properties via interaction with transmembrane receptors, AdipoR1 and AdipoR2. Evidence suggests that low levels of adiponectin may be a useful marker for atherosclerotic disease. A proposed anti-atherogenic mechanism of adiponectin involves its ability to promote cholesterol efflux. We performed a systematic review of the role of adiponectin in cholesterol efflux and HDL biogenesis, and of the proteins and receptors believed to be implicated in this process. Nineteen eligible studies (7 clinical, 11 fundamental, 1 clinical + fundamental) were identified through Ovid Medline, Ovid Embase, and Pubmed, that support the notion that adiponectin plays a key role in promoting ABCA1-dependent cholesterol efflux and in modulating HDL biogenesis via activation of the PPAR-γ/LXR-α signalling pathways in macrophages. AdipoR1 and AdipoR2 are suggested to also be implicated in this process, however the data are conflicting/insufficient to establish any firm conclusions. Once the exact mechanisms are unravelled, adiponectin may be critical in defining future treatment strategies directed towards increasing HDL functionality and ultimately reducing atherosclerotic disease.

Beneficial Effects of Adiponectin on Glucose and Lipid Metabolism and Atherosclerotic Progression: Mechanisms and Perspectives

Circulating adiponectin concentrations are reduced in obese individuals, and this reduction has been proposed to have a crucial role in the pathogenesis of atherosclerosis and cardiovascular diseases associated with obesity and the metabolic syndrome. We focus on the effects of adiponectin on glucose and lipid metabolism and on the molecular anti-atherosclerotic properties of adiponectin and also discuss the factors that increase the circulating levels of adiponectin. Adiponectin reduces inflammatory cytokines and oxidative stress, which leads to an improvement of insulin resistance. Adiponectin-induced improvement of insulin resistance and adiponectin itself reduce hepatic glucose production and increase the utilization of glucose and fatty acids by skeletal muscles, lowering blood glucose levels. Adiponectin has also β cell protective effects and may prevent the development of diabetes. Adiponectin concentration has been found to be correlated with lipoprotein metabolism; especially, it is associated with the metabolism of high-density lipoprotein (HDL) and triglyceride (TG). Adiponectin appears to increase HDL and decrease TG. Adiponectin increases ATP-binding cassette transporter A1 and lipoprotein lipase (LPL) and decreases hepatic lipase, which may elevate HDL. Increased LPL mass/activity and very low density lipoprotein (VLDL) receptor and reduced apo-CIII may increase VLDL catabolism and result in the reduction of serum TG. Further, adiponectin has various molecular anti-atherosclerotic properties, such as reduction of scavenger receptors in macrophages and increase of cholesterol efflux. These findings suggest that high levels of circulating adiponectin can protect against atherosclerosis. Weight loss, exercise, nutritional factors, anti-diabetic drugs, lipid-lowering drugs, and anti-hypertensive drugs have been associated with an increase of serum adiponectin level.

The role of inflammatory markers following Ramadan Fasting

Objectives:

The aim of present study was to investigate the effect of fasting during Ramadan on plasma adiponectin and TNF-α levels.

Methods:

This is a cross sectional study, conducted at Federal Urdu University of Arts, Science & Technology (FUUAST), Karachi, comprising a total of 55 (50%) females and 55 (50%) males whose ages ranged between 20 and 40 years, and fasted during Ramadan (June-July 2014) were enrolled in the study. Subjects were separated into normal weight, overweight and obese males and females. Anthropometric measurements and Fasting venous blood samples were taken at first and last (29^th) day of Ramadan. Plasma adiponectin and TNF-alpha levels were assayed with ELISA kits. All values were calculated and presented as mean ± standard error of the mean (SEM) and by using analysis of variance (ANOVA) for repeated measures. P values < 0.05 were accepted as significant.

Results:

Body mass index (BMI) (Kg/m2) in over-weight and obese male subjects exhibited considerable reduction (P<0.05; P<0.05), post Ramadan when compared to their respective pre Ramadan fasting weights. Noticeable and significant reduction was also observed in BMI of obese females (P<0.05). Post Ramadan Overweight Males (P<0.05) and Post Ramadan Obese Males (P<0.001) exhibited significantly elevated plasma adiponectin (μg/mL) values. While plasma adiponectin mean concentration of only obese females were significantly improved at last week of Ramadan (P<0.01). Fasting in Ramadan significantly decreased TNF-α (pg/mL) levels of post obese males and females than Pre-Ramadan-groups (P<0.05; P<0.01) respectively.

Conclusion:

The study reports of noticeable changes with Ramadan fasting resulting increase of plasma adiponectin and decrease of TNF-α levels as well as body weight. The study strongly suggests further investigations on larger sample sizes with possible association of dietary restrictions and weight loss on mechanism of enhanced adiponectin and reduced TNF-α in obese and overweight persons who fast on Ramadan pattern.

Hypolipidemic effect and protection ability of liver-kidney functions of melanin from Lachnum YM226 in high-fat diet fed mice

In the present study, we investigated the hypolipidemic properties of melanin from Lachnum YM226 (LM) in high-fat diet induced hyperlipidemic mice. After the hyperlipidemic model was established, mice were randomly divided into six groups, as follows: normal control group (NC), hyperlipidemic control group (HC), positive control group (7 mg kg^-1 d^-1 simvastatin) (PC) and LM groups (50, 100 and 200 mg kg^-1 d^-1 denoted as LM-50, LM-100 and LM-200, respectively). Subsequently, the body weight, organ indices, lipid metabolism, antioxidant properties and liver-kidney functions of the mice were examined. Moreover, the activities of lipoprotein metabolism enzymes in serum and liver tissue were examined to study the feasible mechanism. The results imply that LM could effectively reduce body weight, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and atherogenic index (AI), and increase high density lipoprotein cholesterol (HDL-C). Moreover, treatment with LM also increased the antioxidant enzymes activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) and reduced malondialdehyde (MDA) content relative to the HC group. In addition, the liver and kidney damage indices such as alanine aminotransferase (ALT), aspartate aminotransaminase (AST), alkaline phosphatase (ALP), creatinine (CRE), blood urea nitrogen (BUN) and uric acid were lowered. LM administration also significantly corrected disturbances of liver-kidney functions with no fatty deposits in the liver, resulting in a protective effect against renal histological alteration. The hypolipidemic effect occurred partly due to the regulation of hepatic lipase (HL) and lipoprotein lipase (LPL) in serum and liver to markedly decrease TG. This confirms the important role of LM in the prevention of hyperlipidemia.

Metabolomic profiling implicates adiponectin as mediator of a favorable lipoprotein profile associated with NT-proBNP

Background

The N-terminal prohormone of brain natriuretic peptide (NT-proBNP) is an important biomarker for the diagnosis of heart failure. Apart from this and only recently recognized, NT-proBNP levels associate with higher HDL- and lower LDL-cholesterol levels comprising a favorable blood lipid profile. To further examine this observation, the lipoprotein profile in relation to NT-proBNP was examined in-depth by proton nuclear magnetic resonance spectroscopy (¹H-NMR). We complemented this investigation with a state-of-the-art untargeted metabolomics approach.

Methods

Lipoprotein particles were determined by ¹H-NMR spectroscopy in 872 subjects without self-reported diabetes from the population-based Study of Health in Pomerania (SHIP)-TREND with available NT-proBNP measurements. Comprehensive metabolomics data for plasma and urine samples were obtained. Linear regression models were performed to assess the associations between serum concentrations of NT-proBNP and the metabolites/lipoprotein particles measured in plasma or urine.

Results

An increase in serum NT-proBNP was associated with a benefical lipoprotein profile, including a decrease in VLDL, IDL and LDL-particles along with an increase in large HDL particles. These findings were replicated in a second independent cohort. Serum concentrations of NT-proBNP showed significant inverse associations with seven plasma metabolites while associations with 39 urinary metabolites, mostly comprising amino acids and related intermediates, were identified. Mediation analyses revealed adiponection as mediating factor for the associations observed with lipoproteins particles.

Conclusions

Most of the metabolic changes associated with NT-proBNP implicate significant influence on the blood lipid profile besides vasodilatory and the diuretic action of BNP signaling. Our data suggest that the more favorable lipoprotein profile as associated with elevated NT-proBNP concentrations in mainly cardiac healthy individuals might relate to adiponectin signaling indicating even indirect cardio-protective effects for NT-proBNP.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0765-1) contains supplementary material, which is available to authorized users.

Adiponectin Predicts High-Density Lipoprotein Cholesterol Efflux Capacity in Adults Irrespective of Body Mass Index and Fat Distribution

CONTEXT

Obesity is associated with hypoadiponectemia, dyslipidemia, and increased risk of cardiovascular disease (CVD). Mechanisms linking these conditions remain to be fully understood. Cholesterol efflux capacity (CEC) is a crucial functional property of high-density lipoprotein (HDL) that strongly predicts CVD incidence.

OBJECTIVE

We investigated whether age, fat distribution, and other obesity-related factors affect CEC in juvenile and adult overweight/obese participants of the STYJOBS/EDECTA cohort (NCT00482924).

DESIGN

We performed an observational study.

MAIN OUTCOME MEASURES

CEC and its association with body measures and related metabolic parameters was assessed in 683 participants (281 juveniles, of whom 227 were overweight/obese; 402 adults, of whom 197 were overweight/obese).

RESULTS

Pearson correlation analysis showed that, after Bonferroni correction, CEC was significantly inversely correlated with body mass index (BMI), carotid diameter, waist circumference, waist-to-hip, waist-to-height ratio, oxidized low-density lipoprotein, and uric acid and with the liver markers alanine-aminotransferase and choline esterase. CEC was positively correlated with HDL cholesterol, total cholesterol, apolipoprotein A1, and adiponectin in adults, whereas in juveniles only apolipoprotein A1 showed a significant positive correlation with CEC. Age-stratified linear regression analyses with CEC as the outcome variable identified adiponectin as the most significant predictor of CEC in adults. The results did not change when either BMI or waist-to-hip ratio as a factor of fat distribution was included in the models.

CONCLUSIONS

Hypoadiponectemia is a robust predictor of reduced cholesterol efflux capacity in adults irrespective of BMI and fat distribution. Further investigations are needed to assess whether adiponectin is a causal determinant of CEC.

A New Optimized Percutaneous Access System for CIPII

In recent years, continuous intraperitoneal insulin infusion (CIPII) has become a favored treatment alternative for patients with subcutaneous insulin resistance, mainly due to its ability of mimicking physiological conditions of insulin absorption. CIPII has been shown to improve glycemic control as well as to reduce hypoglycemic events and to lead to increased patient satisfaction and quality of life (QoL). Among CIPII delivery systems, Diaport stands out due to its low side effects, its demonstrated clinical efficacy and the potential for integration into closed-loop systems.

Adipose tissue: an endocrine organ playing a role in metabolic regulation

Adipose tissue is a complex endocrine organ with an intricate role in whole body homeostasis. Beyond storing energy, adipose tissue is fundamental in numerous processes including, but not limited to, metabolism, food intake and immune cell function. Adipokines and cytokines are the signaling factors from adipose tissue. These factors play a role in maintaining health, but are also candidates for pathologies associated with obesity. Indeed excessive adiposity causes dysregulation of these factors which negatively affect health and contribute to numerous obesity-induced co-morbidities. In particular, adipokines are fundamental in regulation of glucose homeostasis and insulin signaling, thus aberrant production of these adipose derived hormones correlates with the development and progression of type 2 diabetes. Therefore, elucidation of adipose regulation is crucial for understanding the pathophysiological basis of obesity and metabolic diseases such as type 2 diabetes. In the present review, we summarize current data on the relation between adipokines and adipose depot derived cytokines in the maintenance of glucose homeostasis. Specifically, physiological and molecular functions of several adipokines are defined with particular focus on interactions within the insulin-signaling pathway and subsequent regulation of glucose uptake in both standard and obesity-induced dysregulated conditions. This same relation will be discussed for cytokines and inflammation as well.

Diet, Exercise, and C-Reactive Protein Levels in People With Abdominal Obesity: The ATTICA Epidemiological Study

We evaluated the association of physical activity and diet with C-reactive protein (CRP) levels among subjects with abdominal obesity. During 2001-2002, we enrolled 625 men (18 to 87 years old) and 712 women (18 to 89 years old) with abdominal obesity (waist-to-hip ratio ≥0.95 in men and ≥0.8 in women) from the Attica area, Greece. The sampling was stratified by the age-gender distribution of the region (census 2001). Among several variables, we also measured plasma high-sensitivity CRP, physical activity status, dietary habits, blood lipids, and blood pressure levels. Adherence to the Mediterranean diet was evaluated through a diet score (0 to 55) that assessed the inherent characteristics of the diet. Compared with those with low CRP levels, subjects with high CRP levels (ie, >3.0 mg/L) were physically inactive (P = .01), were less likely to adopt the Mediterranean diet (P = .008), had higher glucose levels, had a higher prevalence of hypertension, had a lower high-density lipoprotein cholesterol, and had increased smoking habits and higher anthropometric indices (all P < .05). Moreover, adoption of the Mediterranean diet in combination with medium physical activity seems to reduce the likelihood of having high CRP levels by 72% (P = .018), irrespective of smoking and various clinical and biological characteristics. Among subjects with abdominal obesity, low-grade systemic inflammation appears to be associated with the adoption of an unfavorable lifestyle, including physical inactivity and unhealthy dietary habits, as well as increased blood pressure levels and low high-density lipoprotein cholesterol.

The Associations Between Helicobacter pylori Infection, Serum Vitamin D, and Metabolic Syndrome: A Community-Based Study

The associations between Helicobacter pylori infection, serum vitamin D level, and metabolic syndrome (MS) are controversial. The present community-based study aimed to investigate the effect of H pylori infection and serum vitamin D deficiency on MS development.Individuals from the northeastern region of Taiwan were enrolled in a community-based study from March, 2014 to August, 2015. All participants completed a demographic survey and underwent the urea breath test (UBT) to detect H pylori infection as well as blood tests to determine levels of vitamin D, adiponectin, leptin, and high-sensitivity C-reactive protein. The ATP III criteria for MS were used in this study.A total of 792 men and 1321 women were enrolled. The mean age was 56.4 ± 13.0 years. After adjusting for age and sex, the estimated odds of MS development for a UBT-positive subject were 1.503 (95% confidence interval [CI]: 1.206-1.872, P < 0.001) when compared to a UBT-negative subject. For participants with vitamin D deficiency (<20 ng/mL), the odds of MS development were 1.423 (95% CI: 1.029-1.967, P = 0.033) when compared to those with sufficient vitamin D level (>30 ng/mL). For participants with both H pylori infection and vitamin D deficiency, the odds of MS development were 2.140 (95% CI: 1.348-3.398, P = 0.001) when compared to subjects without H pylori infection and with sufficient vitamin D levels.H pylori infection and vitamin D deficiency could be predictors of MS. For individuals with both H pylori infection and vitamin D deficiency, the odds of MS development were 2.140 when compared to individuals without H pylori infection and with sufficient vitamin D levels.

Potential Anti-Atherosclerotic Properties of Astaxanthin

Astaxanthin is a naturally occurring red carotenoid pigment classified as a xanthophyll, found in microalgae and seafood such as salmon, trout, and shrimp. This review focuses on astaxanthin as a bioactive compound and outlines the evidence associated with its potential role in the prevention of atherosclerosis. Astaxanthin has a unique molecular structure that is responsible for its powerful antioxidant activities by quenching singlet oxygen and scavenging free radicals. Astaxanthin has been reported to inhibit low-density lipoprotein (LDL) oxidation and to increase high-density lipoprotein (HDL)-cholesterol and adiponectin levels in clinical studies. Accumulating evidence suggests that astaxanthin could exert preventive actions against atherosclerotic cardiovascular disease (CVD) via its potential to improve oxidative stress, inflammation, lipid metabolism, and glucose metabolism. In addition to identifying mechanisms of astaxanthin bioactivity by basic research, much more epidemiological and clinical evidence linking reduced CVD risk with dietary astaxanthin intake is needed.

Oral L-Arginine Administration Improves Anthropometric and Biochemical Indices Associated With Cardiovascular Diseases in Obese Patients: A Randomized, Single Blind Placebo Controlled Clinical Trial

BACKGROUND

Recently, the potential of L-arginine supplementation as a novel and effective strategy for weight loss and improving biochemical parameters in obese patients has been under consideration.

OBJECTIVES

To evaluate the influence of 8-week oral L-arginine supplementation on body mass index (BMI), waist circumference (WC), triceps skinfold (TS), subscapular skinfold (SS), systolic blood pressure (SBP), diastolic blood pressure (DBP), plasma fasting blood sugar (FBS), glycated hemoglobin (HbA1c), triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and malondialdehyde (MDA) in patients with BMI values > 29.9 or visceral obesity (WC > 102 cm in men or > 88 cm in women).

PATIENTS AND METHODS

Ninety obese patients were included in a single-blind randomized controlled trial. Patients were randomized to receive either L-arginine (3 or 6 g thrice daily) or placebo for 8 weeks. Anthropometric and biochemical indices, dietary intake, and blood pressure values were measured at the baseline and after the 8-week intervention.

RESULTS

Significant decreases in anthropometric parameters, blood pressure (SBP, DBP), FBS, HbA1c, LDL, MDA (P < 0.001), TG (P = 0.02), and TC (P = 0.002) and a significant increase in HDL (P < 0.001) were observed in the intervention group, compared to the control group. In the control group, no significant differences were found between the baseline and end-of-intervention measurements.

CONCLUSIONS

In conclusion, oral L-Arginine supplementation appears to improve anthropometric parameters, blood pressure values, and some blood biochemical indices associated with cardiovascular disease prevention.

ADIPOQ single nucleotide polymorphism: Association with adiponectin and lipoproteins levels restricted to men

Adiponectin is an adipokine inversely correlated with obesity, which has beneficial effect on insulin resistance and lipid metabolism. Considering its potential as a therapeutic target in the metabolic disorder contexts, and in order to add knowledge in the area, our study evaluated the ADIPOQ 276G > T polymorphism effect on adiponectin levels, and on lipoproteins of clinical interest in a population sample composed of 211 healthy individuals. Significant effects were observed only among men: the carriers of heterozygous genotype (GT) showed high levels of adiponectin (p = 0.018), while the rare homozygous genotype (TT) gave its carriers a negative phenotype, represented by higher levels of low density lipoprotein cholesterol (LDL-C) (p = 0.004 and p = 0.005) and total cholesterol (TC) (p = 0.010 and p = 0.005) compared to carriers of other genotypes (GG and GT respectively), the independent effect of SNP on LDL-C and TC levels was confirmed by multiple regression analysis (p = 0.008 and p = 0.044). We found no evidence of correlation between circulating adiponectin levels and biochemical markers, which suggests, therefore, an SNP 276G > T independent effect on adiponectin levels and on lipoprotein metabolism in men enrolled in this study.

Hepatic Lipase: a Comprehensive View of its Role on Plasma Lipid and Lipoprotein Metabolism

Hepatic lipase (HL) is a key enzyme catalyzing the hydrolysis of triglycerides (TG) and phospholipids (PLs) in several lipoproteins. It is generally recognized that HL is involved in the remodeling of remnant, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and the production of small, dense low-density lipoproteins (sd-LDLs).On the other hand, it is unclear whether HL accelerates or retards atherosclerosis. From the clinical point of view, HL deficiency may provide useful information on answering this question, but the rarity of this disease makes it impossible to conduct epidemiological study.In this review, we describe a comprehensive and updated view of the clinical significance of HL on lipid and lipoprotein metabolism.

Elevated Lipoprotein Lipase Activity Does Not Account for the Association Between Adiponectin and HDL in Type 1 Diabetes

CONTEXT

Increased high-density lipoprotein cholesterol (HDL-C) is common in type 1 diabetes (T1D) and is associated both with hyperadiponectinemia and with elevated lipoprotein lipase activity (LPL). Because adiponectin has been shown to increase LPL expression, elevated LPL may link the hyperadiponectinemia in T1D with increased HDL.

OBJECTIVE

The purpose of this study was to determine whether LPL activity accounts for the association between adiponectin and HDL in T1D.

DESIGN, PARTICIPANTS, AND SETTING

A cohort of 127 patients with T1D attending the Diabetes Clinic at the University of Miami and 103 healthy control subjects were recruited.

MAIN OUTCOME MEASURE

HDL-C and adiponectin were measured in the full cohort and in a subgroup, HDL subfractions were obtained by ultracentrifugation, and LPL and hepatic lipase were measured in postheparin plasma.

RESULTS

Total HDL-C and the lowest density HDL subfraction, apolipoprotein A-I, LPL activity, and adiponectin levels were higher in subjects with T1D than in control subjects (P < .05). Both adiponectin and LPL activity were directly associated with total HDL-C and its lowest density subfraction, but adiponectin and LPL were not correlated (P = 0.13). Adiponectin alone explained 11.6% and adiponectin plus LPL explained 23.8% of the HDL-C variance. In a multivariate model, adiponectin remained an independent predictor of HDL-C along with LPL and serum creatinine, explaining together 27% of HDL-C variance.

CONCLUSIONS

Adiponectin was strongly associated with HDL-C in T1D, suggesting that hyperadiponectinemia is linked to the elevated HDL-C in this population. However, this relationship is independent of the association between LPL and HDL-C. Thus, elevated adiponectin and LPL activity are independently related to increased HDL-C in T1D.

Intraperitoneal insulin infusion: treatment option for type 1 diabetes resulting in beneficial endocrine effects beyond glycaemia

Continuous intraperitoneal insulin infusion (CIPII) is a treatment option for patients with type 1 diabetes mellitus who fail to reach adequate glycaemic control despite intensive subcutaneous (SC) insulin therapy. CIPII has clear advantages over SC insulin administration in terms of pharmacokinetic and pharmacodynamic properties and has been shown to improve glycaemic regulation. Due to the delivery of insulin predominantly in the portal vein, as opposed to systemically, CIPII offers a unique research model to investigate the effects of insulin on endocrine and metabolic parameters in vivo. The aim of the present article is to provide an overview of the literature with respect to the effects of CIPII on glucose management, quality of life, complications and costs, with additional focus on metabolic and endocrine aspects. Finally, future use and research objectives are discussed.

The metabolic and pharmacologic bases for treating atherogenic dyslipidaemia

Dyslipoproteinaemia is a cardinal feature of the metabolic syndrome that accelerates atherosclerosis. It is characterized by high plasma concentrations of triglyceride-rich and apolipoprotein (apo) B-containing lipoproteins, with depressed high-density lipoprotein (HDL) and increased small dense low-density lipoprotein (LDL) particle concentrations. Dysregulation of lipoprotein metabolism in the metabolic syndrome may be due to a combination of overproduction of very-low density lipoprotein (VLDL) apoB, decreased catabolism of apoB-containing particles, and increased catabolism of HDL apoA-I particles. These abnormalities are due to a global metabolic effect of insulin resistance and visceral obesity. Lifestyle modifications (dietary restriction and increased exercise) and pharmacological treatments favourably alter lipoprotein transport by decreasing the hepatic secretion of VLDL-apoB and the catabolism of HDL apoA-I, as well as by increasing the clearance of LDL-apoB. The safety and tolerability of combination drug therapy based on statins is important and merits further investigation. There are several pipeline therapies for correcting triglyceride-rich lipoprotein and HDL metabolism. However, their clinical efficacy, safety and cost-effectiveness remain to be demonstrated.

Obesity and its metabolic complications: the role of adipokines and the relationship between obesity, inflammation, insulin resistance, dyslipidemia and nonalcoholic fatty liver disease

Accumulating evidence indicates that obesity is closely associated with an increased risk of metabolic diseases such as insulin resistance, type 2 diabetes, dyslipidemia and nonalcoholic fatty liver disease. Obesity results from an imbalance between food intake and energy expenditure, which leads to an excessive accumulation of adipose tissue. Adipose tissue is now recognized not only as a main site of storage of excess energy derived from food intake but also as an endocrine organ. The expansion of adipose tissue produces a number of bioactive substances, known as adipocytokines or adipokines, which trigger chronic low-grade inflammation and interact with a range of processes in many different organs. Although the precise mechanisms are still unclear, dysregulated production or secretion of these adipokines caused by excess adipose tissue and adipose tissue dysfunction can contribute to the development of obesity-related metabolic diseases. In this review, we focus on the role of several adipokines associated with obesity and the potential impact on obesity-related metabolic diseases. Multiple lines evidence provides valuable insights into the roles of adipokines in the development of obesity and its metabolic complications. Further research is still required to fully understand the mechanisms underlying the metabolic actions of a few newly identified adipokines.

Major components of metabolic syndrome and adiponectin levels: a cross-sectional study

BACKGROUND

Adiponectin is a major regulator of glucose and lipid homeostasis by its insulin sensitizer properties. Since decreased insulin sensitivity is linked to metabolic syndrome (MS), decreased adiponectin levels may be related to its development. The purpose of the study was to investigate the relationship between adiponectin levels and MS.

METHODS

Firstly, we cross-sectionally examined subjects with or without MS submitted to an oral glucose tolerance test at Hospital de Clínicas de Porto Alegre (n = 172). A replication analysis was performed in subjects (n = 422) undergoing cardiac angiography at Hospital São Paulo. Subchronic inflammation (US-CRP), coagulation marker (fibrinogen), insulin sensitivity and resistance (Matsuda ISI and HOMA-IR) were estimated. Plasma total and high molecular weight (HMW) adiponectin were measured.

RESULTS

Total and HMW adiponectin levels were lower in MS subjects (P < 0.05). Total adiponectin levels were lower in the presence of high waist circumference, low HDL-cholesterol and elevated triglyceride criteria in both samples and by elevated blood pressure and glucose criteria in Porto Alegre. HMW adiponectin levels were lower in the presence of low HDL-cholesterol, elevated triglycerides, and glucose criteria. Total adiponectin levels were positively related with HDL-cholesterol and ISI Matsuda, negatively related with waist circumference, glucose, triglycerides, HOMA-IR, and US-CRP and not related with blood pressure. While adjusting for sex and age, increased adiponectin levels remained associated with a reduced prevalence ratio for MS in both cohorts (P = 0.001).

CONCLUSIONS

Adiponectin levels decreased with increasing number of MS criteria, and it is in part determined by its relationship with HDL, triglycerides and abdominal adiposity.

Modulation of adiponectin as a potential therapeutic strategy

Adiponectin is produced predominantly by adipocytes and plays an important role in metabolic and cardiovascular homeostasis through its insulin-sensitizing actions and anti-inflammatory and anti-atherogenic properties. Recently, it has been observed that lower levels of adiponectin can substantially increase the risk of developing type 2 diabetes, metabolic syndrome, atherosclerosis, and cardiovascular disease in patients who are obese. Circulating adiponectin levels are inversely related to the inflammatory process, oxidative stress, and metabolic dysregulation. Intensive lifestyle modifications and pharmacologic agents, including peroxisome proliferator-activated receptor-γ or α agonists, some statins, renin-angiotensin-aldosterone system blockers, some calcium channel blockers, mineralocorticoid receptor blockers, new β-blockers, and several natural compounds can increase adiponectin levels and suppress or prevent disease initiation or progression, respectively, in cardiovascular and metabolic disorders. Therefore, it is important for investigators to have a thorough understanding of the interventions that can modulate adiponectin. Such knowledge may lead to new therapeutic approaches for diseases such as type 2 diabetes, metabolic syndrome, cardiovascular disease, and obesity. This review focuses on recent updates regarding therapeutic interventions that might modulate adiponectin.

Role of SN1 lipases on plasma lipids in metabolic syndrome and obesity

OBJECTIVE

To assess the phospholipase activity of endothelial (EL) and hepatic lipase (HL) in postheparin plasma of subjects with metabolic syndrome (MS)/obesity and their relationship with atherogenic and antiatherogenic lipoproteins. Additionally, to evaluate lipoprotein lipase (LPL) and HL activity as triglyceride (TG)-hydrolyses to complete the analyses of SN1 lipolytic enzymes in the same patient.

APPROACH AND RESULTS

Plasma EL, HL, and LPL activities were evaluated in 59 patients with MS and 36 controls. A trend toward higher EL activity was observed in MS. EL activity was increased in obese compared with normal weight group (P=0.009) and was negatively associated with high-density lipoprotein-cholesterol (P=0.014 and P=0.005) and apolipoprotein A-I (P=0.045 and P=0.001) in control and MS group, respectively. HL activity, as TG-hydrolase, was increased in MS (P=0.025) as well as in obese group (P=0.017); directly correlated with low-density lipoprotein-cholesterol (P=0.005) and apolipoprotein B (P=0.003) and negatively with high-density lipoprotein-cholesterol (P=0.021) in control group. LPL was decreased in MS (P<0.001) as well as in overweight and obese compared with normal weight group (P=0.015 and P=0.004, respectively); inversely correlated %TG-very low-density lipoproteins (P=0.04) and TG/apolipoprotein B index (P=0.013) in control group. These associations were not found in MS.

CONCLUSIONS

We describe for the first time EL and HL activity as phospholipases in MS/obesity, being both responsible for high-density lipoprotein catabolism. Our results elucidate part of the remaining controversies about SN1 lipases activity in MS and different grades of obesity. The impact of insulin resistance on the activity of the 3 enzymes determines the lipoprotein alterations observed in these states.

Adiponectin and lipoprotein metabolism

Adiponectin is secreted by the adipose tissue and it has been shown to be down-regulated in states of insulin resistance and in cardiovascular disease. It has also been found to be correlated with various parameters of lipoprotein metabolism, and in particular, it is associated with the metabolism of high-density lipoprotein (HDL) and triglycerides; adiponectin appears to induce an increase in serum HDL, and conversely, HDL can up-regulate adiponectin levels, and in addition, adiponectin lowers serum triglycerides through enhancement of the catabolism of triglyceride-rich lipoproteins. Studies investigating whether adiponectin is causally linked with lipoprotein metabolism have yielded conflicting data, and the mechanisms underlying the interplay between adiponectin and lipoproteins remain to be elucidated. The adiponectin-HDL relationship can explain at least in part the presumed protective role of adiponectin in cardiovascular disease and the adiponectin changes observed after dieting, exercise and lipid-lowering treatment. Statins, fibrates, niacin and n-3 fatty acids may influence circulating adiponectin levels, indicating that adiponectin may mediate some of the metabolic effects of these agents. Further studies to investigate more thoroughly the role of adiponectin in lipoprotein metabolism in the human setting should be carefully planned, focusing on causality and the possible impact of adiponectin on the pathogenesis of cardiovascular disease.

Assessment of adiponectin level in obese and lean Nepalese population and its possible correlation with lipid profile: A cross-sectional study

OBJECTIVE

Adiponectin- one of the most important adipokines plays a pivotal role in carbohydrate and lipid metabolism and vascular biology. Changing food trend and lifestyle has tremendously affected the health status of Nepalese population. Studies have shown that between 1996 and 2006 obesity in Nepal has increased from 1.6% to 10%. Studies have been conducted in Nepal on the prevalence of obesity and its correlation with lipid profile. But based on our knowledge, this is the first study correlating adiponectin with obesity and lipid profile in Nepal. This piece of work will certainly help to assess the impact of obesity in Nepalese population.

MATERIALS AND METHODS

Fifty four obese and Thirty six normal/lean participants were included from different locations of Kathmandu Valley. Anthropometric measurements like age, BMI, Waist circumference, hip circumference, waist to hip ratio, mid thigh circumference and chest circumferences were taken from each participant. Blood glucose, lipid profile and serum adiponectin levels were measured from overnight fasting samples.

RESULTS

Significant differences were observed in BMI, Waist Circumference, Hip Circumference, Waist to Hip Ratio (WHR) and Chest circumference between obese and normal groups. Fasting Blood Glucose, Serum Triglyceride, HDL Cholesterol, LDL Cholesterol, Total Cholesterol/HDL ratio, Non-HDL Cholesterol and Adiponectin Levels were significant between the groups. Inverse correlations were observed between adiponectin level and BMI, Waist Circumference, Hip Circumference, Waist to Hip ratio, Chest Circumference, Fasting Blood Glucose, Triglyceride, Total Cholesterol/HDL ratio, LDL/HDL Cholesterol ratio and Non-HDL Cholesterol levels. Positive correlation was found between adiponectin and HDL Cholesterol levels.

CONCLUSION

Our study showed significant inverse association of serum adiponectin with obesity and lipid profile parameters except for Serum HDL Cholesterol level in Nepalese population.

Hypoadiponectinemia: a useful marker of dyslipidemia in women with polycystic ovary syndrome

OBJECTIVE

Adiponectin plays a role in obesity, lipid metabolism, and anti-inflammation. Women with polycystic ovary syndrome (PCOS) are also at risk for dyslipidemia. Therefore, we investigated the association between adiponectin levels and the lipid profile including high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TGs) in women with PCOS and contemplated what role adiponectin might play in dyslipidemia with PCOS.

MATERIALS AND METHODS

We recruited 118 young Taiwanese women with PCOS. The women enrolled were not taking any medication and those with other systemic diseases of nonovarian origin, which could have affected the hypothalamic-pituitary-ovarian axis, were excluded. The serum lipid profile, metabolic and hormonal parameters, and adiponectin were measured. The lipid profile and adiponectin were analyzed and adjusted for age, body mass index (BMI), homeostasis model assessment-insulin resistance (HOMA-IR), and sex hormone-binding globulin (SHBG).

RESULTS

In a simple linear regression, adiponectin was significantly inversely related to LDL-C and TGs, but positively related to HDL-C (all p < 0.001) after logarithmic transformation. In the multiple linear regression, adiponectin was significantly related to HDL-C (p < 0.001) independent of age, BMI, HOMA-IR, and SHBG after logarithmic transformation. Using a logistic regression, the odds ratio was 0.088 between the association of increased adiponectin and abnormal HDL-C (≤ 50 mg/dL).

CONCLUSIONS

We demonstrated that adiponectin is an independent biomarker that is positively and evidently related to HDL-C and TGs in women with PCOS. Hypoadiponectinemia may be a useful marker of dyslipidemia in women with PCOS.

Metabolic risk susceptibility in men is partially related to adiponectin/leptin ratio

BACKGROUND

High adiponectin/leptin ratio may be protective from metabolic risks imparted by high triglyceride, low HDL, and insulin resistance.

METHODS

This cross-sectional study examines plasma adipokine levels in 428 adult men who were subgrouped according to low (<6.5  μ g/mL)and high (≥6.5  μ g/mL)adiponectin levels or a low or high ratio of adiponectin/leptin.

RESULTS

Men with high adiponectin/leptin ratio had lower plasma triglyceride and higher HDL cholesterol than those with low ratio. Similarly, those with high adiponectin/leptin ratio had lower TG/HDL cholesterol ratio and HOMA2-IR than those with low ratio. In contrast, levels of adiponectin or the ratio of adiponectin/leptin did not associate with systolic blood pressure. But the ratio of adiponectin/leptin decreased progressively with the increase in the number of risk factors for metabolic syndrome.

CONCLUSION

Adipokine levels may reflect adipose tissue triglyceride storage capacity and insulin sensitivity. Leptin is an index of fat mass, and adiponectin is a biomarker of triglyceride metabolism and insulin sensitivity. Men with high adiponectin/leptin ratios have better triglyceride profile and insulin sensitivity than men with a low ratio regardless of waist girth.

Endothelial Lipase Activity Predicts High-Density Lipoprotein Catabolism in Hemodialysis

Objective—

A novel phospholipase assay was used to measure for the first time the behavior of endothelial and hepatic phospholipase activities in postheparin human plasma of hemodialyzed patients and its relationship with atherogenic and antiatherogenic lipoprotein levels.

Methods and Results—

Endothelial and hepatic phospholipase activity was assessed in a total SN1-specific phospholipase assay, using (1-decanoylthio-1-deoxy-2-decanoyl-sn-glycero-3-phosphoryl) ethylene glycol as the substrate. Hemodialyzed patients presented lower values of total and hepatic phospholipase activity than controls: 4.4 (1.9–9.0) versus 7.5 (3.6–18.0) and 2.6 (0.7–6.2) versus 6.6 (1.3–15.2) μmol of fatty acid released per milliliter of postheparin plasma per hour, respectively ( P <0.001); however, endothelial lipase (EL) phospholipase activity was increased in patients: 1.7 (0.8–3.0) versus 1.1 (0.1–2.7) μmol of fatty acid released per milliliter of postheparin plasma per hour ( P =0.008). EL was negatively associated with high-density lipoprotein (HDL)-cholesterol ( r =–0.427; P =0.001), and apolipoprotein A-I levels, total phospholipase, and hepatic lipase activity were directly associated with low-density lipoprotein-cholesterol and apolipoprotein B. The association of EL and HDL-cholesterol remained significant when adjusting for waist circumference (β=–0.26; P =0.05), and the effect of hepatic lipase on low-density lipoprotein-cholesterol continued after adjusting for age (β=0.46; P = 0.001).

Conclusion—

Our results support the hypothesis that EL is the predominant enzyme responsible for lipolytic catabolism of HDLs in hemodialyzed patients and resolve the apparent paradox observed between low hepatic lipase activity and decreased HDL-cholesterol levels observed in these patients. In addition, the ability to assess total hepatic lipase and EL phospholipase activity in plasma will increase our knowledge of the mechanisms involved in controlling HDL levels and cardiovascular risk in hemodialyzed patients, as well as other populations with low levels of HDL-cholesterol.

Hepatic lipase activity is increased in non-alcoholic fatty liver disease beyond insulin resistance

BACKGROUND AND OBJECTIVE

Hepatic lipase is a lipolytic enzyme mostly synthesized and localized at the surface of liver sinusoidal capillaries, which hydrolyses triglycerides and phospholipids of intermediate density, large low density (LDL) and high density lipoproteins. Hepatic lipase activity is increased in insulin resistant states. Non-alcoholic fatty liver disease (NAFLD) is characterized by insulin resistance. However, at present, no data are available regarding the behaviour of hepatic lipase with regard to the degree of hepatic steatosis. Our aim was to evaluate hepatic lipase activity in NAFLD patients and its relationship to the severity of hepatic steatosis.

DESIGN AND PATIENTS

We studied 48 patients with NAFLD (diagnosed by ultrasonography and confirmed by liver biopsy) and 30 controls. Steatosis was semi-quantitatively assessed and considered as mild or grade 1, moderate or grade 2 and severe or grade 3.

MEASUREMENTS

hepatic lipase activity, lipid and lipoprotein profile (including intermediate density lipoproteins and dense LDL), adiponectin, insulin, glucose and high sensitivity C-reactive protein were measured. Homeostasis model assessment for insulin resistance (HOMA) index was calculated.

RESULTS

Patients with hepatic steatosis presented with higher hepatic lipase activity, HOMA and dense LDL and lower levels of adiponectin, high density lipoproteins, cholesterol and apoA-I. Hepatic lipase activity positively correlated significantly with the severity of hepatic steatosis. Hepatic lipase correlated with a more atherogenic profile and persisted higher in patients even after corrected for age, gender, body mass index, HOMA and adiponectin.

CONCLUSION

The higher hepatic lipase activity in NAFLD patients contributes to a more atherogenic profile linked to increased cardiovascular risk, beyond the insulin resistance and the reduction in adiponectin.

Unacylated Ghrelin is associated with the isolated low HDL-cholesterol obese phenotype independently of insulin resistance and CRP level

BACKGROUND

Low plasma high-density lipoprotein-cholesterol (HDL-c) level is commonly present in obesity and represents an independent cardiovascular risk factor. However, obese patients are a very heterogeneous population and the factors and mechanisms that contribute to low HDL-c remain unclear. The aim of this study was to investigate the association between plasma HDL-c levels and plasma hormonal profiles (insulin, adiponectin, resistin, leptin and ghrelin) in subsets of class II and III obese patients.

METHODS

Fasting plasma levels of glucose, total cholesterol, LDL-c, HDL-c, triglycerides, free fatty acids, apoproteins A-I, B-100, B-48, C-II, C-III, insulin, hs-CRP, adipocytokines (adiponectin, resistin, leptin), unacylated ghrelin, body composition (DXA) and resting energy expenditure were measured in three subsets of obese patients: 17 metabolically abnormal obese (MAO) with metabolic syndrome and the typical metabolic dyslipidaemia, 21 metabolically healthy obese (MHO) without metabolic syndrome and with a normal lipid profile, and 21 isolated low HDL-c obese patients (LHO) without metabolic syndrome, compared to 21 healthy lean control subjects.

RESULTS

Insulin resistance (HOMA-IR) increased gradually from MHO to LHO and from LHO to MAO patients (p < 0.05 between MHO and MAO and between LHO and MAO). In multiple regression analysis, serum unacylated ghrelin levels were only positively and independently associated with HDL-c levels in the LHO group (p = 0.032).

CONCLUSIONS

These results suggest that, in class II and III obese patients with an isolated low HDL-c phenotype, unacylated ghrelin is positively associated with HDL-c level independently of insulin resistance and CRP levels, and may contribute to the highly prevalent low HDL-c level seen in obesity.

Adiponectin and risk of coronary heart disease in apparently healthy men and women (from the EPIC-Norfolk Prospective Population Study)

The objective of the present study was to evaluate the association between adiponectin levels and incidence of coronary heart disease (CHD). We performed a prospective case-control analysis nested in the EPIC-Norfolk cohort. Participants were apparently healthy men and women 45 to 79 years of age who developed fatal or nonfatal CHD during an average follow-up period of 7.7 ± 1.1 years. In total 1,035 participants with incident CHD were matched for age, gender, and enrollment time to 1,920 controls who remained free of CHD over the study follow-up. Baseline nonfasting plasma adiponectin concentrations were determined by enzyme-linked immunosorbent assay. Adiponectin levels were lower in participants with CHD than in matched controls (men 8.74 vs 9.13 μg/ml, p = 0.01; women 12.6 vs 13.4 μg/ml, p = 0.03). A 1-μg/ml increment in adiponectin was associated with decreased CHD risk (odds ratio 0.78, 95% confidence interval 0.63 to 0.96, p = 0.02, in men; odds ratio 0.73, 95% confidence interval 0.55 to 0.96, p = 0.03, in women). However, this association was no longer significant after adjustment for established cardiovascular risk factors. Stratification of participants according to metabolic syndrome status showed that men and women with metabolic syndrome had a higher CHD risk, irrespective of their adiponectin levels. In conclusion, although a low adiponectin concentration is associated with an increased CHD risk, findings of the present study do not suggest that its measurement is useful to refine CHD risk assessment once traditional risk factors and clinical features of the metabolic syndrome have been considered.

Adiponectin and lipid profiles compared with insulins in relation to early growth of British South Asian and European children: the Manchester children's growth and vascular health study

CONTEXT

Adiponectin, high-density lipoprotein cholesterol (HDL-C) and insulin concentrations may be important in the pathophysiology of cardiovascular disease.

OBJECTIVE

We tested the hypothesis that serum adiponectin rather than insulin differs from early life, between South Asians and Europeans, with a potentially key role in excess cardiovascular risk characteristic of adult South Asians.

DESIGN AND PARTICIPANTS

We conducted a longitudinal study of 215 British-born children of European (n = 138) and South Asian (n = 77) origin, from birth to 3 yr.

MAIN OUTCOME MEASURE

Serum adiponectin, insulin, proinsulin and HDL-C concentrations were assessed in relation to ethnic group and growth in anthropometric variables from 0-3 yr of age.

RESULTS

Serum adiponectin was lower in South Asian children, despite their smaller size, notable at age 3-6 months (9.5 vs. 11.8 mg/liter; P = 0.04), with no ethnic differences in serum lipids or insulin or proinsulin. In mixed-effects longitudinal models for HDL-C, determinants were adiponectin (P = 0.034), age (P < 0.001), and body mass index (P < 0.001) but not ethnicity. None of these or growth variables affected either insulin or proinsulin. In a fully adjusted mixed-effects longitudinal model including age, sex, insulin, and proinsulin, the independent determinants of serum adiponectin were height [21.3 (95% confidence interval = 31.7-10.8 cm lower, for every 1 mmol/liter increase in adiponectin, P < 0.001], HDL-C [2.8 (1.3-4.2) mmol/liter higher, P < 0.0001], body mass index (lower, P = 0.03), and South Asian ethnicity (lower, P = 0.01).

CONCLUSIONS

These British South Asian-origin infants have lower serum adiponectin but no differences in HDL-C or insulin molecules. In South Asians, factors affecting adiponectin metabolism in early life, rather than insulin resistance, likely determine later excess cardiovascular risk.

Plasma apo/lipoproteins disturbances as a precondition for metabolic syndrome in HCV seronegative heroin addicts

BACKGROUND

Dyslipidemia in heroin addicts is considered to be a precondition for developing metabolic syndrome.

OBJECTIVES

The aim was to evaluate the frequency in serum lipid disturbances of hepatitis C virus (HCV) seronegative heroin addicts; the capacity of high-density lipoprotein (HDL)-C and apolipoprotein B (apoB)/apolipoprotein A-I (apoA-I) for predicting hypertriglyceridemia/low HDL-C profile; correlation of HDL-C with the apoB/apoA-I and their correlation to plasma apo/lipoproteins.

MATERIALS AND METHODS

Sixty-six heroin addicts, seronegative for HCV and HIV, without liver morphological changes were divided into two groups according to their decreased/normal HDL-C concentrations.

RESULTS

We registered decreased HDL-C in 58.8% of the addicts; decreased apoA-I in 50.9%, increased triglyceride (TGL) in 35.9%, and increased apoB/apoA-I in 3.8% of the patients; and 25.7% had hypertriglyceridemia/low HDL profile. Addicts with low HDL-C had higher TGL (1.73 ± .91 vs. 1.31 ± .71, pр = .02) compared with addicts with normal HDL-C and the controls. Low HDL-C group had higher apoB/apoA-I compared with addicts with normal HDL-C (.62 ± .28 vs. .42 ± .11, pр = .000). HDL-C inversely correlated to apoB/apoA-I (p = -.452, pр = .001). ApoB/apoA-I showed stronger correlation with the observed apo/lipoproteins than the HDL-C. The logistic regression model showed that apoB/apoA-I index (OR 89.1, 95% CI 1.3-5971.2) is more significant predictor in developing hypertriglyceridemia/low HDL profile than HDL-C.

CONCLUSION

Heroin addiction is associated with decreased plasma concentrations of HDL-C, apoA-I, apoB, and increased TGL concentrations. In heroin addicts, HDL-C concentrations are significantly associated with the apoB/apoA-I index, which correlates to all lipid fractions and is a stronger predictor of metabolic syndrome lipid profile in heroin addicts.