The Macrophage‐Specific Serum Marker,Soluble CD163, Is Increased in Obesity and Reduced After Dietary‐Induced Weight Loss

Objective: Soluble CD163 (sCD163) is a new macrophage‐specific serum marker elevated in inflammatory conditions. sCD163 is elevated in obesity and found to be a strong predictor of the development of type 2 diabetes. We investigated whether dietary intervention and moderate exercise was related to changes in sCD163 and how sCD163 is associated to insulin resistance in obesity. Design and Methods: Ninety‐six obese subjects were enrolled: 62 followed a very low energy diet (VLED) program for 8 weeks followed by 3‐4 weeks of weight stabilization, 20 followed a moderate exercise program for 12 weeks, and 14 were included without any intervention. Fasting blood samples and anthropometric measures were taken at baseline and after intervention. Thirty‐six lean subjects were included in a control group. Results: sCD163 was significantly higher in obese subjects (2.3 ± 1.0 mg/l) compared with lean (1.6 ± 0.4 mg/l, P < 0.001). Weight loss (11%) induced by VLED resulted in a reduction and partial normalization of sCD163 to 2.0 ± 0.9 mg/l (P < 0.001). Exercise for 12 weeks had no effect on sCD163. At baseline, sCD163 was significantly correlated with BMI (r = 0.46), waist circumference (r = 0.40), insulin resistance measured by the homeostasis model assessment (HOMA‐IR; r = 0.41; all P < 0.001), and the leptin‐to‐adiponectin ratio (r = 0.28, P < 0.05). In a multivariate linear regression analysis with various inflammatory markers, sCD163 (β = 0.25), adiponectin (β = ?0.24), and high sensitivity C‐reactive protein (hs‐CRP; β = 0.20) remained independently and significantly associated to HOMA‐IR (all P < 0.05). After further adjustment for waist circumference, only sCD163 was associated with HOMA‐IR (P < 0.05). Conclusion: The macrophage‐specific serum marker sCD163 is increased in obesity and partially normalized by dietary‐induced weight loss but not by moderate exercise. Furthermore, we confirm that sCD163 is a good marker for obesity‐related insulin resistance.     

Characterization of a second highly conserved B-type lamin present in cells previously thought to contain only a single B-type lamin

Previous analyses of the nuclear lamina of mammalian cells have revealed three major protein components (lamins A, B and C) that have been identified by protein sequence homology as members of the intermediate filament (IF) protein family. It has been claimed that mammalian cells contain either all three lamins or lamin B alone. Using monoclonal antibodies specific for B-type lamins and cDNA cloning we identified a second major mammalian B-type lamin (murine lamin B₂), thus showing that lamin composition in mammals is more complex than previously thought. Lamin B₂ is coexpressed with lamin B₁ (formerly termed lamin B) in all somatic cells and mammalian species that we analysed, including a variety of cells currently believed to contain only a single lamin. This suggests that two B-type lamins are necessary to form a functional lamina in mammalian somatic cells. By cDNA cloning we found thatXenopus laevis lamin L_II is the amphibian homolog of mammalian lamin B₂. Lamin expression during embryogenesis of amphibians and mammals shows striking similarities. The first lamins expressed in the early embryo are the two B-type lamins, while A-type lamins are only detected much later in development. These findings indicate that the genomic differentiation into two B-type lamins occurred early in vertebrate evolution and has been maintained in both their primary structure and pattern of expression.     

Suppression of lamin A/C by short hairpin RNAs promotes adipocyte lineage commitment in mesenchymal progenitor cell line, ROB-C26

Lamin A/C gene encodes a nuclear membrane protein, and mutations in this gene are associated with diverse degenerative diseases that are linked to premature aging. While lamin A/C is involved in the regulation of tissue homeostasis, the distinct expression patterns are poorly understood in the mesenchymal cells differentiating into adipocytes. Here, we examined the expression of lamin A/C in a rat mesenchymal progenitor cell-line, ROB-C26 (C26). Immunocytochemical analysis showed that lamin A/C was transiently down-regulated in immature adipocytes, but its expression increased with terminal differentiation. To elucidate the role of lamin A/C expression on mesenchymal cell differentiation, lamin A/C expression was suppressed using short hairpin RNA (shRNA) molecules in C26 cells. In the absence of adipogenic stimuli, lamin A/C shRNA decreased alkaline phosphatase (ALP) activity, but induced preadipocyte factor -1 (Pref-1) mRNA expression. In the presence of adipogenic stimuli, lamin A/C knockdown promotes adipocytes differentiation, as assessed by the detection of an increase in Oil Red O staining. RT-PCR analysis showed that lamin A/C shRNA resulted in increased mRNA expression of PPARγ2 and aP2 during adipocyte differentiation. These results suggest that decreased lamin A/C expression levels not only suppress osteoblast phenotypes but also promote adipocyte differentiation in C26 cells.     

Leisure‐Time Physical Activity and Reduced Plasma Levels of Obesity‐Related Inflammatory Markers

Objective: This study investigated the relationship between physical activity and the obesity‐related inflammatory markers C‐reactive protein, interleukin‐6, and soluble tumor necrosis factor receptors (sTNF‐Rs) 1 and 2. Furthermore, we examined the relationship between physical activity and insulin sensitivity (insulin, C‐peptide, and hemoglobin A_1c levels) and whether inflammatory markers mediate this association. Research Methods and Procedures: Biomarkers were measured in 405 healthy men and 454 healthy women from two large ongoing prospective studies. Information about physical activity and other variables was assessed by questionnaires. Results: After adjustment for other predictors of inflammation, physical activity was inversely associated with plasma levels of sTNF‐R1, sTNF‐R2, interleukin‐6, and C‐reactive protein (p = 0.07, p = 0.004, p = 0.04, and p = 0.009). After further adjustment for BMI and leptin, as a surrogate for fat mass, most of these associations were no longer significant. Physical activity was also inversely related to insulin and C‐peptide levels (p = 0.008 and p < 0.001); however, in contrast to BMI and leptin, levels of inflammatory markers explained only very little of this inverse relationship. Discussion: These results suggest that frequent physical activity is associated with lower systemic inflammation and improved insulin sensitivity. These associations can partially be explained by a lower degree of obesity in physically active subjects. Although inflammatory markers may mediate obesity‐dependent effects of physical activity on inflammatory related diseases such as type 2 diabetes or coronary heart disease, our study suggests that they do not directly account for the beneficial effects of physical activity on insulin resistance.     

Age-related changes in lamin A/C expression in cardiomyocytes

Lamin A and C (A/C) are type V intermediate filaments that form the nuclear lamina. Lamin A/C mutations lead to reduced expression of lamin A/C and diverse phenotypes such as familial cardiomyopathies and accelerated aging syndromes. Normal aging is associated with reduced expression of lamin A/C in osteoblasts and dermal fibroblasts but has never been assessed in cardiomyocytes. Our objective was to compare the expression of lamin A/C in cardiomyocytes of old (24 mo) versus young (4 mo) C57Bl/6J mice using a well-validated mouse model of aging. Lamin B1 was used as a control. Immunohistochemical and immunofluorescence analyses showed reduced expression of lamin A/C in cardiomyocyte nuclei of old mice (proportion of nuclei expressing lamin A/C, 9% vs. 62%, P < 0.001). Lamin A/C distribution was scattered peripherally and perinuclear in old mice, whereas it was homogeneous throughout the nuclei in young mice. Western blot analyses confirmed reduced expression of lamin A/C in nuclear extracts of old mice (ratio of lamin A/C to B1, 0.6 vs. 1.2, P < 0.01). Echocardiographic studies showed increased left ventricular wall thickness with preserved cavity size (concentric remodeling), increased left ventricular mass, and a slight reduction in fractional shortening in old mice. This is the first study to show that normal aging is associated with reduced expression and altered distribution of lamin A/C in nuclei of cardiomyocytes.     

Monocyte chemoattractant protein-1 in obesity and type 2 diabetes. Insulin sensitivity study

Objective: Our goal was to test any association between human plasma circulating levels of monocyte chemoattractant protein‐1 (cMCP‐1) and insulin resistance and to compare monocyte chemoattractant protein‐1 (MCP‐1) adipose tissue gene expression and cMCP‐1 in relation with inflammatory markers. Research Methods and Procedures: cMCP‐1 was measured in n = 116 consecutive control male subjects to whom an insulin sensitivity (S_i) test was performed. Circulating levels of soluble CD14, soluble tumor necrosis factor receptor type 2 (sTNFR2), soluble interleukin‐6 (sIL‐6), and adiponectin also were measured. Subcutaneous adipose tissue samples were obtained from n = 107 non‐diabetic and type 2 diabetic subjects with different degrees of obesity. Real‐time polymerase chain reaction was used to measure gene expression of MCP‐1, CD68, tumor necrosis factor‐α (TNF‐α), and its receptor TNFR2. Results: In the S_i study, no independent effect of cMCP‐1 levels on insulin sensitivity was observed. In the expression study, in non‐diabetic subjects, MCP‐1 mRNA had a positive correlation with BMI (r = 0.407, p = 0.003), TNF‐α mRNA (r = 0.419, p = 0.002), and TNFR2 mRNA (r = 0.410, p = 0.003). In these subjects, cMCP‐1 was found to correlate with waist‐to‐hip ratio (r = 0.322, p = 0.048). In patients with type 2 diabetes, MCP‐1 mRNA was up‐regulated compared with non‐diabetic subjects. TNF‐α mRNA was found to independently contribute to MCP‐1 mRNA expression. In this group, CD68 mRNA was found to correlate with BMI (r = 0.455, p = 0.001). Discussion: cMCP‐1 is not associated with insulin sensitivity in apparently healthy men. TNF‐α is the inflammatory cytokine associated with MCP‐1 expression in subcutaneous adipose tissue.     

Impact of Information About Obesity Genomics on the Stigmatization of Overweight Individuals: An Experimental Study

Advances in genomic technologies are rapidly leading to new understandings of the roles that genetic variations play in obesity. Increasing public dissemination of information regarding the role of genetics in obesity could have beneficial, harmful, or neutral effects on the stigmatization of obese individuals. This study used an online survey and experimental design to examine the impact of genetic versus non‐genetic information on obesity stigma among self‐perceived non‐overweight individuals. Participants (n = 396) were randomly assigned to read either genetic, non‐genetic (environment), or gene—environment interaction obesity causal information. A total of 48% of participants were female; mean age was 42.7 years (range = 18–86 years); 75% were white; 45.2% had an annual household income of less than $40,000; mean BMI was 23.4 kg/m². Obesity stigma was measured using the Fat Phobia Scale — short form (FPS‐S). After reading the experimental information, participants in the genetic and gene—environment conditions were more likely to believe that genetics increase obesity risk than participants in the non‐genetic condition (both P < 0.05), but did not differ on obesity stigma. Obesity stigma was higher among whites and Asians than Hispanics and African Americans (P = 0.029), and associated with low self‐esteem (P = 0.036). Obesity stigma was also negatively associated with holding 'germ or virus' (P = 0.033) and 'overwork' (P = 0.016) causal beliefs about obesity, and positively associated with 'diet or eating habits' (P = 0.001) and 'lack of exercise' (P = 0.004) causal beliefs. Dissemination of brief information about the role of genetics in obesity may have neither a beneficial nor a harmful impact on obesity stigmatization compared with non‐genetic information among self‐perceived non‐overweight individuals.     

ADIPOQ Polymorphisms,Monounsaturated Fatty Acids,and Obesity Risk: The GOLDN Study

Serum adiponectin levels have been positively associated with insulin sensitivity and are decreased in type 2 diabetes (T2D) and obesity. Genetic and environmental factors influence serum adiponectin and may contribute to risk of metabolic syndrome and T2D. Therefore, we investigated the effect of ADIPOQ single‐nucleotide polymorphisms (SNPs), ?11377C>G and ?11391G>A, on metabolic‐related traits, and their modulation by dietary fat in white Americans. Data were collected from 1,083 subjects participating in the Genetics of Lipid Lowering Drugs and Diet Network study. Mean serum adiponectin concentration was higher for carriers of the ?11391A allele (P = 0.001) but lower for the ?11377G allele carriers (P = 0.017). Moreover, we found a significant association with obesity traits for the ?11391G>A SNP. Carriers of the ?11391A allele had significantly lower weight (P = 0.029), BMI (P = 0.019), waist (P = 0.003), and hip circumferences (P = 0.004) compared to noncarriers. Interestingly, the associations of the ?11391G>A with BMI and obesity risk were modified by monounsaturated fatty acids (MUFAs) intake (P‐interaction = 0.021 and 0.034 for BMI and obesity risk, respectively). In subjects with MUFA intake above the median (≥13% of energy intake), ?11391A carriers had lower BMI (27.1 kg/m² for GA+AA vs. 29.1 kg/m² for GG, P = 0.002) and decreased obesity risk (odds ratio for ?11391A = 0.52, 95% confidence interval (CI); 0.28–0.96; P = 0.031). However, we did not detect genotype‐related differences for BMI or obesity in subjects with MUFA intake <13%. Our findings support a significant association between the ?11391G>A SNPs and obesity‐related traits and the potential to moderate such effects using dietary modification.     

Association of Obesity,but not Diabetes or Hypertension,with Glucocorticoid Receptor N363S Variant

Objective: To determine whether the N363S variant in the glucocorticoid receptor (encoded by nuclear receptor subfamily 3, group C, member 1: NR3C1) is associated with obesity, type 2 diabetes, or hypertension. Research Methods and Procedures: This was a cross‐sectional case‐control study involving 951 Anglo‐Celtic/Northern European subjects from Sydney. This study consisted of the following: 1) an obesity clinic group, most of whom had “morbid obesity” (mean BMI for group = 43 ± 8 kg/m²; n = 152); 2) a type 2 diabetes clinic group (n = 356); 3) patients with essential hypertension who had a strong family history (n = 141); and 4) normal healthy controls (n = 302). N363S genotype, BMI, and a range of other parameters relevant to each group were measured. Results: Compared with the frequency of 0.04 in nonobese healthy subjects, the S363 allele was significantly higher in obesity clinic patients (0.17; p = 5.6 × 10^?8), subjects with diabetes who were also obese (0.09; p = 0.0045), subjects with hypertension who were also overweight (0.08; p = 0.0016), and overweight healthy subjects (0.12; p = 0.0004). Discussion: The NR3C1 N363S variant is associated with obesity and overweight in a range of patient settings but is not associated with hypertension or type 2 diabetes.     

BMI and Rates of Suicide in the United States: An Ecological Analysis

BMI has been inversely associated with risk of completed suicide in several cohort studies, but putative mechanisms for this association and its generalizability throughout the United States are uncertain. We ascertained recent population‐based, state‐level data on rates of obesity, completed suicide (by method), firearm ownership, smoking, major depression, income, education, white race, and nonmetropolitan residence, compiled from federal agencies and surveys, and determined the adjusted population‐weighted correlations of statewide obesity rates with measures of completed and attempted suicide. Statewide prevalence of obesity was strongly inversely correlated with age adjusted suicide rate (multivariable‐adjusted r = ?0.66; P < 0.001). The correlation was somewhat stronger for rates of nonfirearm‐related (r = ?0.75; P < 0.001) than firearm‐related suicides (r = ?0.53; P < 0.001), and was of similar magnitude as the positive correlations of firearm prevalence with suicide rate (r = 0.75; P < 0.001) or of obesity with prevalence of diabetes (r = 0.41; P = 0.006). In analyses of fatal and nonfatal suicidal acts, obesity rates were inversely correlated with rates of suicidal acts using firearms (r = ?0.53; P = 0.02) and suffocation (r = ?0.76; P < 0.001) but not other methods. Obesity rates were also inversely correlated with the case–fatality ratios of acts using poisoning (r = ?0.51; P = 0.01). Thus, statewide rates of obesity are strongly inversely correlated with rates of completed suicide in multivariable analyses, a finding that appears to relate to fewer attempts by suffocation and a lower case–fatality ratio for poisonings, although the mechanism for the inverse correlation with firearm‐related suicides requires further elucidation.     

Which Obesity Index Best Explains Prevalence Differences in Type 2 Diabetes Mellitus?

Objective: Obesity drives the diabetes epidemic. However, it is not known which obesity index best explains variations in type 2 diabetes mellitus prevalence across populations. Research Methods and Procedures: We analyzed three cross‐sectional studies from San Antonio, TX, (Mexican‐Americans and non‐Hispanic whites, n = 2839), Mexico City (n = 2233), and Spain (n = 2161) (age range, 35 to 64 years). We used the area under the receiver operating characteristic curve (AUC) to assess performance for identifying diabetic subjects and logistic regression analysis to examine differences in diabetes prevalence. Results: AUCs for waist circumference and BMI were similar in white subjects, but the AUC for waist circumference was greater in Mexican‐origin subjects (Mexican men, 0.594 vs. 0.549, p = 0.008; and women, 0.605 vs. 0.557, p = 0.002; Mexican‐American men, 0.648 vs. 0.600, p < 0.001; and women, 0.744 vs. 0.693, p < 0.001). The AUC for waist‐to‐height ratio tended to be greater than that for waist circumference, but statistical significance was demonstrated only in Mexican women (0.628 vs. 0.613, p = 0.044), Mexican‐American women (0.774 vs. 0.758, p < 0.001), and Spanish women (0.734 vs. 0.715, p = 0.039). No obesity index was consistently superior to the others for explaining differences in diabetes prevalence among populations. Conclusions: In white and Mexican‐origin men, waist circumference may be the preferred marker for identifying diabetic subjects on account of its simplicity; in women, waist‐to‐height ratio may be better. Differences in diabetes prevalence among these populations cannot be attributed to a single measure of obesity.     

Plasma MR‐proADM Correlates to BMI and Decreases in Relation to Leptin After Gastric Bypass Surgery

Adrenomedullin (ADM) is a vasoactive peptide found to be related to obesity and its comorbidities: type 2 diabetes, hypertension, atherosclerosis, and coronary heart disease. ADM is increased both in plasma and in adipose tissue of obese individuals when compared to lean subjects and is considered as a member of the adipokine family. We determined plasma midregional proadrenomedullin (MR‐proADM) concentrations in a cohort of 357 subjects with BMI ranging from 17.5 to 42.3 kg/m² and no additional medical history. In parallel, 28 severely obese patients scheduled to undergo laparoscopic Roux‐en‐Y gastric bypass (RYGB) surgery were studied at two time points: before and 1 year after surgery. Outcome measurements were: MR‐proADM, cortisol, leptin, C‐reactive protein (CRP) thyroid‐stimulating hormone (TSH), creatinine and metabolic parameters. BMI correlated significantly to plasma MR‐proADM levels (r = 0.714, P < 0.001), also after adjustment for age and gender (r = 0.767, P < 0.001). In obese subjects, there was a positive relationship between MR‐proADM and leptin (r = 0.511, P = 0.006). Following RYGB, plasma MR‐proADM decreased from 0.76 ± 0.03 to 0.62 ± 0.02 pg/ml (P < 0.0001). RYGB‐induced changes in MR‐proADM correlated significantly to changes in leptin (r = 0.533, P = 0.004) and in CRP (r = 0.429, P = 0.023). We conclude that BMI is an independent predictor of circulating MR‐proADM levels. Weight loss after RYGB is associated with a significant decrease in plasma MR‐proADM, which is related to surgery‐induced changes in both circulating leptin and systemic inflammation.     

Epigallocatechin‐3‐gallate suppresses the lipid deposition through the apoptosis during differentiation in bovine bone marrow mesenchymal stem cells

Epigallocatechin gallate (EGCG), a major component of tea, has known effects on obesity, fatty liver, and obesity‐related cancer. We explored the effects of EGCG on the differentiation of bovine mesenchymal stem cells (BMSCs, which are multipotent) in a dose‐ and time‐dependent manner. Differentiating BMSCs were exposed to various concentrations of EGCG (0, 10, 50, 100, and 200 µM) for 2, 4, and 6 days. BMSCs were cultured in Dulbecco's modified Eagle's medium (DMEM)/high‐glucose medium with adipogenic inducers for 6 days, and the expression levels of various genes involved in adipogenesis were measured using real‐time polymerase chain reaction (PCR) and Western blotting. We assessed apoptosis by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick‐end labeling (TUNEL) staining of control and EGCG‐exposed cells. We found that EGCG significantly suppressed fat deposition and cell viability (P < 0.05). The mRNA and protein levels of various adipogenic factors were measured. Expression of the genes encoding peroxisome proliferator‐activated receptor gamma (PPARG), CCAAT/enhancer‐binding protein alpha (CEBPA), fatty acid‐binding protein 4 (FABP4), and stearoyl‐CoA desaturase (SCD) were diminished by EGCG during adipogenic differentiation (P < 0.05). We also found that EGCG lowered the expression levels of the adipogenic proteins encoded by these genes (P < 0.05). EGCG induced apoptosis during adipogenic differentiation (P < 0.05). Thus, exposure to EGCG potentially inhibits adipogenesis by triggering apoptosis; the data suggest that EGCG inhibits adipogenic differentiation in BMSCs.     

Meta‐analysis Added Power to Identify Variants in FTO Associated With Type 2 Diabetes and Obesity in the Asian Population

Several common variants in the intron 1 of FTO (fat mass and associated obesity) gene have been reliably associated with BMI and obesity in European populations. We analyzed two variants (rs9939609 and rs8050136) in 4,189 Chinese Han individuals and conducted a meta‐analysis of published studies in Asian population to investigate whether these variants are associated with type 2 diabetes (T2D) and obesity in Asian population. In this study, both the minor allele A of rs9939609 and the minor allele A of rs805136 were associated with increased risk of T2D, independent of measures of BMI; the odds ratios (ORs) per copy of the risk allele were 1.19 for rs9939609 (95% confidence interval (CI), 1.04–1.37; P = 0.01) and 1.22 for rs8050136 (95% CI, 1.07–1.40; P = 0.004) after adjusting for age, sex, and BMI. Our results also showed association with risk of obesity (rs9939609: OR = 1.39 (95% CI 1.04–1.85), P = 0.02; rs8050136: OR = 1.45 (95% CI 1.09–1.93), P = 0.01) but no association with overweight. These results were consistent with the pooled results from our meta‐analysis study (for diabetes, rs8050136, P = 1.3 × 10^?3; rs9939609, P = 9.8 × 10^?4; for obesity, rs8050136, P = 2.2 × 10^?7; rs9939609, P = 9.0 × 10^?9). Our findings indicate that the two variants (rs9939609 and rs8050136) in the FTO gene contribute to obesity and T2D in the Asian populations.     

The Lipid Accumulation Product and All‐cause Mortality in Patients at High Cardiovascular Risk: A PreCIS Database Study

The BMI is the most frequently used marker to evaluate obesity‐associated risks. An alternative continuous index of lipid over accumulation, the lipid accumulation product (LAP), has been proposed, which is computed from waist circumference (WC, cm) and fasting triglycerides (TGs) (mmol/l): (WC ? 65) × TG (men) and (WC ? 58) × TG (women). We evaluated LAP and BMI as predictors of mortality in a high‐risk cohort. Study population included 5,924 new consecutive patients seen between 1995 and 2006 at a preventive cardiology clinic. Fifty‐eight percent of patients were discordant for their LAP and BMI quartiles. Patients whose LAP quartile was greater than BMI quartile had higher mortality compared with those with LAP quartile was lower than BMI quartile (8.2 vs. 5.4% at 6 years, P = 0.007). After adjustment for age, gender, smoking, diabetes mellitus, blood pressure, low‐density lipoprotein‐cholesterol (LDL‐C) and high‐density lipoprotein‐cholesterol (HDL‐C), (ln)LAP was independently associated with mortality (hazard ratio (HR) = 1.46, P < 0.001). BMI was not associated with increased mortality (HR = 1.06, P = 0.39). Adding LAP to a model including traditional risk factors for atherosclerosis increased its predictive value (C statistic 0.762 vs. 0.750, P = 0.048). Adding BMI to the same model did not change its predictive value (0.749 vs. 0.750, P = 0.29). Subgroup analyses showed that LAP predicted mortality in the nondiabetic patients (adjusted HR for (ln)LAP 1.64, P < 0.001), but did not reach significance in the diabetic patients (HR = 1.21, P = 0.11). In conclusion, LAP and not BMI predicted mortality in nondiabetic patients at high risk for cardiovascular diseases. LAP may become a useful tool in clinical practice to stratify the risk of unfavorable outcome associated with obesity.