High Molecular Weight Adiponectin Levels Research Articles

Weight Loss Is More Important Than the Diet Type in Improving Adiponectin Levels Among Overweight/Obese Adults

Objective: The study objective was to compare the effect of a standard calorie- and fat-restricted diet (STD-D) and a calorie- and fat-restricted lacto-ovo-vegetarian diet (LOV-D) on total and high-molecular-weight (HMW) adiponectin levels after 6 months of behavioral intervention. Design: This study is an ancillary study to a randomized clinical trial. Subjects: Subjects included 143 overweight/obese adults (STD-D = 79; LOV-D = 64). Intervention: Both groups received the same standard behavioral intervention; the only difference was that LOV-D participants were instructed to eliminate meat, poultry, and fish from their diet. Measures: Weight, dietary intake with the 3-day food diary, and total and HMW adiponectin levels were measured. Results: Both groups significantly increased total (STD-D +7.2 ± 17.8%; LOV-D +9.4 ± 21.8%) and HMW adiponectin levels (STD-D +18.5 ± 32.9%; LOV-D +15.8 ± 34.5%; ps < 0.05) with no significant differences between the groups. We found significant associations between weight loss and increases in total (β (SE) = −.071(.27); p = 0.003) and HMW adiponectin (β (SE) = −1.37(.47); p = 0.001) levels independent of the diet type. Weight loss at the higher quartile was associated with improvements of adiponectin levels (p < 0.05). Conclusion: Weight loss was associated with increased total and HMW adiponectin levels regardless of the diet type. Enhancing weight loss may be a means to improve adiponectin levels.

Reduction of Intestinal Polyp Formation in Min Mice Fed a High-Fat Diet with Aloe Vera Gel Extract

Aloe vera gel supercritical CO2 extract (AVGE) has been shown to contain five phytosterols, reduce visceral fat accumulation, and influence the metabolism of glucose and lipids in animal model experiments. Recent epidemiologic studies have shown that obesity is an established risk factor for several cancers including colorectal cancer. Therefore, we examined the effects of AVGE on intestinal polyp formation in Apc-deficient Min mice fed a high-fat diet. Male Min mice were divided into normal diet (ND), high fat diet (HFD), low dose AVGE (HFD+LAVGE) and high dose AVGE (HFD+HAVGE) groups. The ND group received AIN-93G diet and the latter 3 groups were given modified high-fat AIN-93G diet (HFD) for 7 weeks. AVGE was suspended in 0.5% carboxymethyl cellulose (CMC) and administered orally to mice in HFD+LAVGE and HFD+HAVGE groups every day (except on Sunday) for 7 weeks at a dose of 3.75 and 12.5 mg/kg body weight, respectively. ND and HFD groups received 0.5% CMC alone. Between weeks 4 and 7, body weights in the HFD and HFD+LAVGE groups were reduced more than those in the ND group. However, body weights were not reduced in the HFD+HAVGE group. Mice were sacrificed at the end of the experiment and their intestines were scored for polyps. No significant differences were observed in either the incidence and multiplicity of intestinal polyps (≥0.5 mm in a diameter) among the three groups fed HFD. However, when intestinal polyps were categorized by their size into 0.5-1.4, 1.5-2.4, or ≥2.5 mm, the incidence and multiplicity of large polyps (≥2.5 mm) in the intestine in the HFD+HAVGE group were significantly lower than those in the HFD group. We measured plasma lipid (triglycerides and total cholesterol) and adipocytokine [interleukin-6 and high molecular weight (HMW) adiponectin] levels as possible indicators of mechanisms of inhibition. The results showed that HMW adiponectin levels in the HFD group were significantly lower than those in the ND group. However, the levels in the HFD+HAVGE group were significantly higher than those in the HFD group. These results indicate that HAVGE reduced large-sized intestinal polyps and ameliorated reduction in plasma HMW adiponectin levels in Min mice fed HFD.

Glucose Use in Fasted Rats Under Sevoflurane Anesthesia and Propofol Anesthesia

We previously reported the marked differences in the effects of sevoflurane anesthesia and propofol anesthesia on glucose use in fed rats; however, we could not elucidate mechanisms underlying the differences. We used fasted rats in this study. After surgical preparation under sevoflurane anesthesia, rats were divided into 3 groups: awake rats, rats under sevoflurane anesthesia, and rats under propofol anesthesia. All rats underwent the IV glucose tolerance test (IVGTT); 0.5 g/kg glucose was administered IV to rats. Just before IVGTT, some rats were pretreated with glibenclamide or diazoxide. We measured glucose, insulin, tumor necrosis factor-α (TNF-α), and high molecular weight adiponectin levels during IVGTT and calculated the quantitative insulin sensitivity check index (QUICKI) using glucose and insulin levels before glucose administration in each rat. Before glucose administration, rats under sevoflurane anesthesia showed similar glucose and insulin levels with significantly higher QUICKI compared with awake rats, while rats under propofol anesthesia showed similar glucose levels and significantly higher insulin levels with significantly lower QUICKI compared with awake rats. After glucose administration, rats under sevoflurane anesthesia showed significantly higher glucose levels and similar insulin levels compared with awake rats, while rats under propofol anesthesia showed similar glucose levels and significantly higher insulin levels compared with awake rats. Before glucose administration, TNF-α levels in rats under sevoflurane anesthesia and rats under propofol anesthesia were similar to those in awake rats. After glucose administration, TNF-α was undetectable in all awake rats and all rats under sevoflurane anesthesia, whereas TNF-α was detectable in all rats under propofol anesthesia; TNF-α levels in rats under propofol anesthesia were significantly higher than those in awake rats. High molecular weight adiponectin levels in rats under sevoflurane anesthesia and rats under propofol anesthesia were similar to those in awake rats throughout the experimental period. In rats under sevoflurane anesthesia, glibenclamide significantly decreased glucose levels and significantly increased insulin levels; however, diazoxide produced no significant effects on glucose and insulin levels. In rats under propofol anesthesia, glibenclamide significantly decreased glucose levels and significantly increased insulin levels, while diazoxide significantly decreased glucose levels without changing insulin levels. Sevoflurane anesthesia attenuates glucose-induced insulin secretion without affecting basic insulin secretion, while propofol anesthesia enhances insulin secretion. Propofol anesthesia exaggerates insulin-resistive conditions, whereas sevoflurane anesthesia dose not impair insulin sensitivity; there may be a possible association of TNF-α with insulin-resistive conditions under propofol anesthesia.

Difference in the ratio of high-molecular weight (HMW) to total adiponectin and HMW adiponectin in late post-menopausal women.

High-molecular weight (HMW) isoform level and HMW ratio have been shown to be better predictors of insulin sensitivity and metabolic syndrome than total adiponectin level.We examined the changes in circulating levels of HMW adiponectin and ratios of HMW to total adiponectin in women during the menopausal transition. We conducted a cross-sectional study in 217 healthy women and divided them into 4 stages: 58 women in pre-menopausal, 69 women in perimenopausal, 62 women in early post-menopausal and 28 women in late post-menopausal phase. Serum levels of total adiponectin and HMW adiponectin were measured by an enzyme-linked immunosorbent assay. In late post-menopausal women, HMW adiponectin level was significantly higher than that in peri-menopausal women and the HMW to total adiponectin ratio was significantly lower than that in early post-menopausal women. In peri-menopausal women, HMW adiponectin level was significantly lower than that in pre-menopausal women and HMW to total adiponectin ratio was significantly lower than the ratios in pre-menopausal and early post-menopausal women. The ratio of HMW to total adiponectin is low in late post-menopausal women, though both levels of total and HMW adiponectin were high after menopause in our cross-sectional study.

THU0120 Do High Molecular Weight Adiponectin Levels Associate with Radiographic Progression in Rheumatoid Arthritis and Hand Osteoarthritis?

BackgroundObesity has been associated with an altered radiographic progression in rheumatoid arthritis (RA) and hand osteoarthritis (OA). While the underlying mechanisms of these associations remain unclear, it has become clear...

Change of serum total and high molecular weight adiponectin levels in type 2 diabetic patients with nonalcoholic fatty liver disease

Objective To investigate the changes and clinical significance of serum total and high molecular weight adiponectin (HMW APN) levels in type 2 diabetic patients with non-alcoholic fatty liver disease (NAFLD).Methods Serum levels of total adiponectin and HMW APN were measured by ELISA,in 58 type 2 diabetic patients with nonalcoholic fatty liver disease (T2DM with NAFLD group),59 type 2 diabetic patients without nonalcoholic fatty liver disease (T2DM group),and 55 control subjects with normal glucose tolerance and without nonalcoholic fatty liver disease (NC group).Results (1) Alanine transaminase and total cholesterol levels were significantly higher in T2DM with NAFLD group than those in NC group(P＜0.01),while body mass index (BMI),aspartate aminotransferase,triglyceride (TG),and fasting insulin were also significantly increased (P＜0.05 or P＜ 0.01),and high density lipoprotein-cholesterol (HDL-C) were significantly decreased compared with those in NC and T2DM groups (P＜0.01).(2) Total adiponectin,HMW APN,and the ratio of HMW APN to total adiponectin in T2DM group were lower than those in NC group.Total adiponectin and HMW APN levels in T2DM with NAFLD group were significantly lower than those in T2DM group(P＜0.01).(3) Regression analysis showed that homeostasis model assessment insulin resistance index (HOMA-IR),TG,and HDL-C levels were independent predicting factors for total adiponectin and HMW APN levels.TG and BMI were independent risk factors for T2DM complicated with NAFLD,while total adiponectin and HMW APN levels were the protective ones (OR =0.701,0.489,respectively).Conclusions Hypoadiponectinemia may partially play an important role in the development and progression of NAFLD in T2DM. Key words: Adiponectin, high molecular weight ; Diabetes mellitus, type 2 ; Fatty liver, non-alcoholic

Total and high molecular weight adiponectin levels and risk of cardiovascular disease in individuals with high blood glucose levels

ObjectiveThe association of adiponectin levels with cardiovascular disease (CVD) may vary by age and health condition. It is unknown whether adiponectin predicts CVD events among individuals with high blood glucose levels. MethodsWe conducted a nested case–control study among 15,566 men and women aged 40–85 years from four communities, who were free of CVD at baseline. During 192,181 person-years of follow-up, 117 individuals subsequently developed coronary heart disease or ischemic stroke and had high plasma glucose concentrations (fasting/nonfasting ≥ 5.6/7.2 mmol/L or treated) at baseline. Controls were randomly selected at a 2:1 ratio and matched for sex, age, blood glucose, year of survey, fasting conditions, and community (n = 234). Baseline total and high molecular weight (HMW) adiponectin and their ratio were examined for total subjects and the association with CVD was compared between ages of 40–69 and 70–85 years. ResultsAfter adjustment for matched variables and traditional risk factors, total and HMW adiponectin and their ratio were not associated with overall risk of CVD. However, significant interactions of the associations between the age groups were found. The highest quartile for HMW adiponectin and HMW/total adiponectin ratio decreased risk of CVD compared with the lowest quartile among middle-aged individuals (multivariable-adjusted odds ratio = 0.33 [95%CI, 0.13–0.83] and 0.47 [0.22–0.98], respectively), while this association was not seen among the elderly. ConclusionsHigh HMW adiponectin levels may decrease the risk of CVD in middle-aged adults with high blood glucose.

Imbalance between Neutrophil Elastase and its Inhibitor α1-Antitrypsin in Obesity Alters Insulin Sensitivity, Inflammation, and Energy Expenditure

The molecular mechanisms involved in the development of obesity and related complications remain unclear. Here, we report that obese mice and human subjects have increased activity of neutrophil elastase (NE) and decreased serum levels of the NE inhibitor α1-antitrypsin (A1AT, SerpinA1). NE null (Ela2(-/-)) mice and A1AT transgenic mice were resistant to high-fat diet (HFD)-induced body weight gain, insulin resistance, inflammation, and fatty liver. NE inhibitor GW311616A reversed insulin resistance and body weight gain in HFD-fed mice. Ela2(-/-) mice also augmented circulating high molecular weight (HMW) adiponectin levels, phosphorylation of AMP-activated protein kinase (AMPK), and fatty acid oxidation (FAO) in the liver and brown adipose tissue (BAT) and uncoupling protein (UCP1) levels in the BAT. These data suggest that the A1AT-NE system regulates AMPK signaling, FAO, and energy expenditure. The imbalance between A1AT and NE contributes to the development of obesity and related inflammation, insulin resistance, and liver steatosis.

Do high molecular weight adiponectin levels associate with radiographic progression in early rheumatiod arthritis and hand osteoarthritis?

Do high molecular weight adiponectin levels associate with radiographic progression in early rheumatiod arthritis and hand osteoarthritis?

Correlation of circulating C1q and C1q-binding adiponectin concentrations with aging in males: a preliminary report

BackgroundAtherosclerosis is an age-related disease. Adiponectin and C1q form a protein complex in human blood, and that serum C1q and C1q-binding adiponectin (C1q-APN) concentrations can be measured. We investigated circulating C1q and C1q-APN levels in Japanese men including elderly men.FindingsThe study subjects were 509 Japanese men including elderly men. Serum levels of total adiponectin (Total-APN), high-molecular weight-adiponectin (HMW-APN), C1q-APN and C1q were measured by enzyme-linked immunosorbent assay. Total-APN, HMW-APN and C1q-APN, but not C1q, correlated significantly and positively with aging (r=0.26, r=0.24, r=0.17, p<0.01, respectively). The HMW-APN/Total-APN ratio correlated significantly and positively with aging (r=0.14, p<0.01). The C1q-APN/Total-APN ratio and C1q-APN/HMW-APN ratio correlated significantly and negatively with aging (r=−0.17, p<0.01, r=−0.12, p=0.01). C1q-APN/C1q correlated significantly and positively with aging (r=0.09, p=0.03). Multiple regression analysis identified age and body mass index as significant determinants of C1q-APN.ConclusionsThe present study demonstrates that serum HMW-APN, C1q-APN, and Total-APN, but not C1q, correlated positively with aging. These preliminary results could form the basis for future research.Trial registrationClinical Trial Registration Number: UMIN000004318

Abstract P291: Adipocytokines, Lipoproteins &amp; Obesity Among Black &amp; White Postmenopausal Women from the Women’s Health Initiative

Background: Despite the prevalence of severe obesity, particularly among women and African-American women, there is little data on CV risk factor differences across the BMI spectrum including extreme obesity. Methods: Participants were 1200 black and white postmenopausal women sampled from the Women’s Health Initiative Observational Study according to BMI categories and waist circumference tertiles: 300 black and 300 white women with BMI 40-65 kg/m 2 and 75 black and 75 white women in BMI categories 8.5-&lt;25, 25-&lt;30, 30-&lt;35 and 35-&lt;40 kg/m 2 . Using stored baseline serum, total and high molecular-weight (HMW) adiponectin, leptin, ghrelin and insulin were measured by immunoassay; plasma lipoproteins and subclasses were measured by NMR spectroscopy. Race-ethnicity differences were tested in linear regression models adjusted for age, diabetes, BMI, waist, hip, hormone therapy and lipid-lowering medication. Results: Compared with white women, black women had lower levels of total and HMW adiponectin and ghrelin, and higher levels of insulin and leptin. Despite similar levels of total LDL particles (LDL-P), black women had lower levels of small LDL-P and higher levels of large LDL-P and larger mean LDL size. Levels of large HDL particles (HDL-P) and small HDL-P were also similar for black and white women, but black women had lower levels of total and medium HDL-P and larger mean HDL particle size. Black women also had lower levels of total, large, medium and small VLDL particles (VLDL-P) which increased little across BMI category, such that mean levels of total or large VLDL-P among black women with BMI≥ 40 kg/m 2 were lower than white women of normal BMI (&lt;25 kg/m 2 ) (Figure). Among white, but not black women, total LDL-P was higher and total HDL-P was lower with higher BMI category (Figure). Conclusions: Among postmenopausal women of similar BMI and waist circumference, black women have lower levels of ghrelin and total and HMW adiponectin, but better lipoprotein levels that are less related to obesity compared with white women.

Adiponectin levels in patients with psoriasis: A meta‐analysis

Conflicting results regarding adiponectin levels in patients with psoriasis have been reported. We carried out a meta-analysis on studies which compared adiponectin levels of psoriatic patients with controls. A published work search was performed through PubMed (MEDLINE), EMBASE and the Cochrane Library for articles published in English. Pooled standardized mean difference (SMD) and 95% confidence intervals (95% CI) were calculated by using random effects and fixed effect models. Heterogeneity between studies was assessed using the Cochran's Q and I(2) statistics. A total of nine studies were enrolled (389 cases and 360 controls) for adiponectin, and three studies were included (132 cases and 132 controls) for high-molecular weight (HMW) adiponectin. Adiponectin and HMW adiponectin levels were not significantly different in patients with psoriasis compared with controls (SMD, -0.151 [95% CI, -0.616 to 0.315]; P = 0.526 for adiponectin; SMD, 0.999 [95% CI, -2.626 to 4.624]; P = 0.589 for HMW adiponectin). The associations were borderline significantly different in the stratum of those with a mean age of less than 40 years (SMD, -0.516 [95% CI: -1.032 to 0]; P = 0.050). Sensitivity analyses were not substantially altered in the direction of effect when any one study was excluded. No publication bias was detected. The level of adiponectin and HMW adiponectin may not be associated with psoriasis. The relationship between psoriasis and adipokines needs more in-depth studies with larger sample sizes.

Lower ratio of high-molecular-weight adiponectin level to total may be associated with coronary high-risk plaque

BackgroundAlthough high-molecular-weight (HMW) adiponectin is believed to protect against atherosclerosis, the association between HMW adiponectin and the composition of coronary plaques is unknown. We evaluated whether the HMW to total adiponectin ratio was associated with the presence of coronary plaque and its composition using multi-slice computed tomography coronary angiography (MSCTCA).MethodsSerum total and HMW adiponectin levels were measured in 53 consecutive patients (age, 71) with >50% coronary artery stenosis detected by MSCTCA. A low-attenuation coronary plaque was defined as a plaque with a mean CT density <50 Hounsfield units. Multivariate logistic regression analyses were performed to evaluate the predictors of the presence of low-attenuation coronary plaques, which is thought to be high risk, on CT.ResultsDecreased serum levels of total as well as HMW adiponectin were significantly associated with the presence of at least one calcified or non-calcified coronary artery plaque (total adiponectin level: odds ratio 0.76, 95% CI 0.58–0.99, P = 0.048; HMW adiponectin level: odds ratio 0.65, 95% CI 0.42–0.99, P = 0.047). A low ratio of HMW to total adiponectin was significantly associated with the presence of low-attenuation coronary plaques (4.55, 1.94–21.90, P = 0.049). However, neither the total adiponectin nor the HMW adiponectin level was associated with the presence of low-attenuation coronary plaques.ConclusionLower total or HMW adiponectin levels are associated with the presence of calcified and non-calcified coronary plaques, whereas a lower ratio of HMW to total adiponectin associated with the presence of low-attenuation coronary plaques (thought to be high risk). Measurement of total and HMW adiponectin levels and the HMW to total adiponectin ratio may be useful for risk stratification of coronary artery plaques.

Effects of pravastatin on serum adiponectin levels in female patients with type 2 diabetes mellitus

ObjectivePravastatin has been reported to elevate circulating adiponectin levels in patients with various insulin resistant state, hypertension, coronary artery disease, and hypercholesterolemia. This study aimed to evaluate whether pravastatin increase serum total and high molecular weight adiponectin levels and improve insulin sensitivity in female patients with type 2 diabetes mellitus and hypercholesterolemia. Patients and designThis study was designed as a multicenter, double-blind, placebo-controlled, factorial randomized trial (placebo and pravastatin at 20 or 40 mg per day). A total of 73 female patients with type 2 diabetes and hypercholesterolemia were enrolled. Changes in total and high molecular weight (HMW) serum adiponectin levels, the ratio of HMW adiponectin to total adiponectin, insulin sensitivity measured by homeostasis model assessment of insulin resistance (HOMA-IR) and lipid profiles were evaluated after 16 weeks in each group. ResultsTotal cholesterol and low-density lipoprotein (LDL) cholesterol levels were significantly reduced after 16 weeks in the pravastatin 20 mg and 40 mg treatment groups compared with the placebo group (P = 0.008 and P = 0.004, respectively). However, there were no significant differences between the 20 mg and 40 mg pravastatin treatment groups in terms of total adiponectin and HMW adiponectin serum levels, as well as insulin sensitivity (P = 0.348 and P = 0.991). ConclusionsIn female patients with type 2 diabetes and hypercholesterolemia, 16 weeks pravastatin therapy did not affect on serum total adiponectin or HMW adiponectin levels.

Breast-feeding vs Formula-feeding for Infants Born Small-for-Gestational-Age: Divergent Effects on Fat Mass and on Circulating IGF-I and High-Molecular-Weight Adiponectin in Late Infancy

Fetal growth restraint, if followed by rapid weight gain, confers risk for adult disease including diabetes. How breast-feeding may lower such risk is poorly understood. OBJECTIVE, STUDY PARTICIPANTS, INTERVENTION, OUTCOMES: In infants born small-for-gestational-age (SGA), we studied the effects of nutrition in early infancy (breast-feeding vs formula-feeding; BRF vs FOF) on weight partitioning and endocrine markers in late infancy. Body composition (by absorptiometry), fasting glycemia, insulin, IGF-I, and high-molecular-weight (HMW) adiponectin were assessed at 4 and 12 months in BRF controls born appropriate-for-GA (N = 31) and in SGA infants receiving BRF (N = 48) or FOF (N = 51), the latter being randomized to receive a standard formula (FOF1) or a protein-rich formula (FOF2). The study was conducted in a University Hospital. SGA-BRF infants maintained a low fat mass and normal levels of IGF-I and HMW adiponectin. In contrast, SGA-FOF infants normalized their body composition by gaining more fat; this normalization was accompanied by a marked fall in HMW adiponectinemia and, in FOF2 infants, by elevated IGF-I levels. In late infancy, SGA-BRF infants were most sensitive to insulin, even more sensitive than appropriate-for-GA-BRF controls. Because the health perspectives are better for SGA-BRF than for SGA-FOF infants, the present results suggest that FOF for SGA infants should aim at maintaining normal IGF-I and HMW-adiponectin levels rather than at normalizing body composition. Nutriceutical research for SGA infants may thus have to be redirected.

Genetic background (DDD/Sgn versus C57BL/6J) strongly influences postnatal growth of male mice carrying the Ay allele at the agouti locus: identification of quantitative trait loci associated with diabetes and body weight loss

BackgroundMice carrying the Ay allele at the agouti locus become obese and are heavier than their non-Ay littermates. However, this does not hold true for the genetic background of the DDD mouse strain. At 22 weeks of age, DDD.Cg-Ay females are heavier than DDD females, whereas DDD.Cg-Ay males are lighter than DDD males. This study aimed to determine the possible cause and identify the genes responsible for the lower body weight of DDD.Cg-Ay males.ResultsGrowth curves of DDD.Cg-Ay mice were analyzed and compared with those of B6.Cg-Ay mice from 5 to 25 weeks. In DDD.Cg-Ay males, body weight gain stopped between 16 and 17 weeks and the body weight gradually decreased; thus, the lower body weight was a consequence of body weight loss. Quantitative trait locus (QTL) mapping was performed in backcrossed (BC) males of DDD × (B6 × DDD.Cg-Ay) F1-Ay mice. For the body weight at 25 weeks, significant QTLs were identified on chromosomes 1 and 4. The DDD allele was associated with a lower body weight at both loci. In particular, the QTL on chromosome 4 interacted with the Ay allele. Furthermore, suggestive QTLs for plasma glucose and high molecular weight adiponectin levels were coincidentally mapped to chromosome 4. The DDD allele was associated with increased glucose and decreased adiponectin levels. When the body weight at 25 weeks and plasma glucose levels were considered as dependent and independent variables, respectively, BC Ay males were classified into two groups according to statistical analysis using the partition method. Mice of one group had significantly higher glucose and lower adiponectin levels than those of the other group and exhibited body weight loss as observed with DDD-Ay males.ConclusionsThe lower body weight of DDD.Cg-Ay male mice was a consequence of body weight loss. Diabetes mellitus has been suggested to be a possible contributory factor causing body weight loss. The QTL on distal chromosome 4 contained the major responsible genes. This QTL interacted with the Ay allele, implying the reason why body weight loss occurs in DDD.Cg-Ay but not in DDD males.

Ratiometric Measurements of Adiponectin by Mass Spectrometry in Bottlenose Dolphins (Tursiops truncatus) with Iron Overload Reveal an Association with Insulin Resistance and Glucagon

High molecular weight (HMW) adiponectin levels are reduced in humans with type 2 diabetes and insulin resistance. Similar to humans with insulin resistance, managed bottlenose dolphins (Tursiops truncatus) diagnosed with hemochromatosis (iron overload) have higher levels of 2 h post-prandial plasma insulin than healthy controls. A parallel reaction monitoring assay for dolphin serum adiponectin was developed based on tryptic peptides identified by mass spectrometry. Using identified post-translational modifications, a differential measurement was constructed. Total and unmodified adiponectin levels were measured in sera from dolphins with (n = 4) and without (n = 5) iron overload. This measurement yielded total adiponectin levels as well as site specific percent unmodified adiponectin that may inversely correlate with HMW adiponectin. Differences in insulin levels between iron overload cases and controls were observed 2 h post-prandial, but not during the fasting state. Thus, post-prandial as well as fasting serum adiponectin levels were measured to determine whether adiponectin and insulin would follow similar patterns. There was no difference in total adiponectin or percent unmodified adiponectin from case or control fasting animals. There was no difference in post-prandial total adiponectin levels between case and control dolphins (mean ± SD) at 763 ± 298 and 727 ± 291 pmol/ml, respectively (p = 0.91); however, percent unmodified adiponectin was significantly higher in post-prandial cases compared to controls (30.0 ± 6.3 versus 17.0 ± 6.6%, respectively; p = 0.016). Interestingly, both total and percent unmodified adiponectin were correlated with glucagon levels in controls (r = 0.999, p < 0.001), but not in cases, which is possibly a reflection of insulin resistance. Although total adiponectin levels were not significantly different, the elevated percent unmodified adiponectin follows a trend similar to HMW adiponectin reported for humans with metabolic disorders.

Low-molecular-weight adiponectin is more closely associated with episodes of asthma than high-molecular-weight adiponectin

Adiponectin is divided into high-molecular-weight (HMW), middle-molecular-weight (MMW) and low-molecular-weight (LMW) types. While HMW adiponectin has been studied by many researchers, the roles of MMW and LMW adiponectin have not yet been sufficiently elucidated. In addition, there are conflicting findings regarding the role of adiponectin in chronic inflammatory diseases, especially asthma. Therefore, we compared patients who suffered episodes of asthma in the past (=asthmatics) with those who did not (=non-asthmatics) in order to investigate the relationship between asthma and HMW, MMW and LMW adiponectin. The subjects in this study included 76 university students. None of the subjects were smokers, on regular medications or seeing a doctor regularly at the time. Fourteen subjects reported past histories of asthma. We also measured and compared the levels of leptin and ghrelin to that of adiponectin, as these hormones are connected with inflammatory conditions. Although the physical data of the asthmatics were similar to those of the non-asthmatics, the levels of ghrelin and all fractions of adiponectin tended to be lower in the asthmatics than in the non-asthmatics. While the levels of MMW and LMW adiponectin in the asthmatics were found to be significantly low, the levels of ghrelin and HMW adiponectin were not clear. According to a multivariate regression analysis of the MMW and LMW adiponectin levels, asthma was found to be more significantly associated with the LMW adiponectin level than age, waist circumference or HDL-C. The results suggest that LMW adiponectin may be associated with episodes of asthma in males.

Adiponectin in mice with altered GH action: links to insulin sensitivity and longevity?

Adiponectin is positively correlated with longevity and negatively correlated with many obesity-related diseases. While there are several circulating forms of adiponectin, the high-molecular-weight (HMW) version has been suggested to have the predominant bioactivity. Adiponectin gene expression and cognate serum protein levels are of particular interest in mice with altered GH signaling as these mice exhibit extremes in obesity that are positively associated with insulin sensitivity and lifespan as opposed to the typical negative association of these factors. While a few studies have reported total adiponectin levels in young adult mice with altered GH signaling, much remains unresolved, including changes in adiponectin levels with advancing age, proportion of total adiponectin in the HMW form, adipose depot of origin, and differential effects of GH vs IGF1. Therefore, the purpose of this study was to address these issues using assorted mouse lines with altered GH signaling. Our results show that adiponectin is generally negatively associated with GH activity, regardless of age. Further, the amount of HMW adiponectin is consistently linked with the level of total adiponectin and not necessarily with previously reported lifespan or insulin sensitivity of these mice. Interestingly, circulating adiponectin levels correlated strongly with inguinal fat mass, implying that the effects of GH on adiponectin are depot specific. Interestingly, rbGH, but not IGF1, decreased circulating total and HMW adiponectin levels. Taken together, these results fill important gaps in the literature related to GH and adiponectin and question the frequently reported associations of total and HMW adiponectin with insulin sensitivity and longevity.

Gender differences in serum high-molecular-weight adiponectin levels in metabolic syndrome

The objective of this study was to estimate gender-specific associations between metabolic syndrome (MS) and high-molecular-weight (HMW) adiponectin in an Estonian adult population. Plasma HMW adiponectin was measured in 458 subjects (191 men) who participated in a population-based cross-sectional multicenter study (n=495) on the prevalence of metabolic disorders in Estonia. MS was defined according to National Cholesterol Education Program Adult Treatment Panel III criteria. Median HMW adiponectin levels (μg/ml) were significantly lower among all subjects with MS compared with subjects without MS: 2.1 vs 2.8 in men (P=0.002) and 3.1 vs 5.1 in women (P<0.001). In a fully adjusted, logistic regression model containing HMW adiponectin, homeostasis model assessment of insulin resistance (HOMA-IR), BMI, and age, HMW adiponectin was significantly associated with MS only in women. Comparison of HMW adiponectin and HOMA-IR as markers for MS indicated that HOMA-IR predicted MS better than did HMW adiponectin in both genders. However, after adjusting for age and BMI, HOMA-IR was a significantly better predictor only in men. HMW adiponectin and HOMA-IR predicted the presence of MS at the same level in women. Areas under the receiver operating characteristic curves for HMW adiponectin and HOMA-IR were 0.833 vs 0.88 in men (P=0.02) and 0.897 vs 0.907 in women (P=0.5). These data suggest that the association between low HMW adiponectin levels and presence of MS might be stronger in women compared with men.