Implementation of low-dose CT screening in two different health care systems: Mount Sinai Healthcare System and Phoenix VA Health Care System.

Implementation of lung screening (LS) programs is challenging even among health care organizations that have the motivation, the resources, and more importantly, the goal of providing for life-saving early detection, diagnosis, and treatment of lung cancer. We provide a case study of LS implementation in different healthcare systems, at the Mount Sinai Healthcare System (MSHS) in New York City, and at the Phoenix Veterans Affairs Health Care System (PVAHCS) in Phoenix, Arizona. This will illustrate the commonalities and differences of the LS implementation process in two very different health care systems in very different parts of the United States. Underlying the successful implementation of these LS programs was the use of a comprehensive management system, the Early Lung Cancer Action Program (ELCAP) Management SystemTM. The collaboration between MSHS and PVAHCS over the past decade led to the ELCAP Management SystemTM being gifted by the Early Diagnosis and Treatment Research Foundation to the PVAHCS, to develop a "VA-ELCAP" version. While there remain challenges and opportunities to continue improving LS and its implementation, there is an increasing realization that most patients who are diagnosed with lung cancer as a result of annual LS can be cured, and that of all the possible risks associated with LS, the greater risk of all is for heavy cigarette smokers not to be screened. We identified 10 critical components in implementing a LS program. We provided the details of each of these components for the two healthcare systems. Most importantly, is that continual re-evaluation of the screening program is needed based on the ongoing quality assurance program and database of the actual screenings. At minimum, there should be an annual review and updating. As early diagnosis of lung cancer must be followed by optimal treatment to be effective, treatment advances for small, early lung cancers diagnosed as a result of screening also need to be assessed and incorporated into the entire screening and treatment program.

Insulin metabolism in human adipocytes from subcutaneous and visceral depots.

Subjects with the metabolic syndrome (insulin resistance, glucose intolerance, dyslipidemia, hypertension, etc.) have a relative increase in abdominal fat tissue compared to normal individuals and obesity has also been shown to be associated with a decrease in insulin clearance. The majority of the clearance of insulin is due to the action of insulin-degrading enzyme (IDE) and IDE is present throughout all tissues. Since abdominal fat is increased in obesity we hypothesized that IDE may be altered in the different fat depots. Adipocytes were isolated from fat samples obtained from subjects during elective abdominal surgery. Fat samples were taken from subcutaneous (SQ) and visceral (VIS) sites. Insulin metabolism was compared in adipocytes isolated from SQ and VIS fat tissue. Adipocytes from the VIS site degraded more insulin that those from SQ fat tissue. Inhibitors of cathepsins B and D has no effect on the degradation of insulin, while bacitracin, an inhibitor of IDE, inhibited degradation by approx. 33% in both SQ and VIS adipocytes. These data show that insulin metabolism is relatively greater in VIS than in SQ fat tissue and potentially due to IDE.

Pioglitazone inhibits the expression of inflammatory cytokines from both monocytes and lymphocytes in patients with impaired glucose tolerance.

OBJECTIVE: The current study determines whether pioglitazone (PIO) therapy reduces both monocyte and lymphocyte inflammatory activity and their ability to induce inflammation in other tissues. METHODS AND RESULTS: Monocyte and lymphocyte cytokine gene and protein expression of interleukin (IL)-6 were first shown to be greater in subjects with impaired glucose tolerance (IGT) than in subjects with normal glucose tolerance. Sixty-six IGT subjects were then randomized to 4,5 months of placebo or PIO therapy. After receiving PIO, subjects had lower triglycerides and higher HDL cholesterol (P<0.05) than did subjects receiving placebo. Monocyte gene and protein expression of IL-1 beta, IL-6, and IL-8 (and IL-2, IL-6 and IL-8 from lymphocytes) was significantly lower after PIO therapy in the resting state, as well as after lipopolysaccharide (LPS) stimulation (P<0.05 for all). Moreover, IL-6, IL-8, and MCP-1 gene expression were decreased by nearly 50% in human adipocytes exposed to conditioned media from monocytes or lymphocytes from PIO treated subjects. CONCLUSIONS: These results demonstrate that PIO therapy in IGT can reduce proinflammatory gene and protein expression from both monocytes and lymphocytes. This intervention also reduces the inflammatory cross-talk between these immune cells and adipose tissue, which could in turn contribute to the metabolic improvements resulting from PIO therapy.

Increased fat accumulation in liver may link insulin resistance with subcutaneous abdominal adipocyte enlargement, visceral adiposity, and hypoadiponectinemia in obese individuals.

BACKGROUND: Enlargement of adipocytes from subcutaneous abdominal adipose tissue (SAT), increased intrahepatic lipid content (IHL), intramyocellular lipid content (IMCL), and low circulating adiponectin concentrations are associated with insulin resistance. OBJECTIVE: Because adiponectin increases fat oxidation in skeletal muscle and liver, and the expression of the adiponectin gene in SAT is inversely associated with adipocyte size, we hypothesized that hypoadiponectinemia links hypertrophic obesity with insulin resistance via increased IMCL and IHL. DESIGN: Fifty-three obese Pima Indians with a mean (+/-SD) age of 27 +/- 8 y, body fat of 35 +/- 5%, and normal glucose regulation (normal fasting and 2-h glucose concentration per WHO 1999 criteria) underwent euglycemic-hyperinsulinemic clamp, biopsies of SAT and vastus lateralis muscle, and magnetic resonance imaging of the abdomen. RESULTS: Adipocyte diameter (AD) correlated positively with body fat (P < 0.0001) and IHL (estimated from magnetic resonance imaging intensity of liver; P = 0.047). No association was found between AD and plasma adiponectin or IMCL. Plasma adiponectin negatively correlated with type II IMCL (IIA, P = 0.004; IIX, P = 0.009) or IHL (P = 0.02). In a multivariate analysis, plasma adiponectin, AD, and visceral adipose tissue (VAT) independently predicted IHL. Low insulin-mediated glucose disposal was associated with low plasma adiponectin (P = 0.02) and high IHL (P = 0.0003), SAT (P = 0.02), and VAT (P = 0.04). High IHL was the only predictor of reduced insulin-mediated suppression of hepatic glucose production (P = 0.02) and the only independent predictor of insulin-mediated glucose disposal in a multivariate analysis. CONCLUSIONS: Increased lipid content in the liver may independently link hypoadiponectinemia, hypertrophic obesity, and increased visceral adiposity with peripheral and hepatic insulin resistance.

Gamma-synuclein is an adipocyte-neuron gene coordinately expressed with leptin and increased in human obesity.

Recently, we characterized tumor suppressor candidate 5 (Tusc5) as an adipocyte-neuron PPARgamma target gene. Our objective herein was to identify additional genes that display distinctly high expression in fat and neurons, because such a pattern could signal previously uncharacterized functional pathways shared in these disparate tissues. gamma-Synuclein, a marker of peripheral and select central nervous system neurons, was strongly expressed in white adipose tissue (WAT) and peripheral nervous system ganglia using bioinformatics and quantitative PCR approaches. Gamma-synuclein expression was determined during adipogenesis and in subcutaneous (SC) and visceral adipose tissue (VAT) from obese and nonobese humans. Gamma-synuclein mRNA increased from trace levels in preadipocytes to high levels in mature 3T3-L1 adipocytes and decreased approximately 50% following treatment with the PPARgamma agonist GW1929 (P < 0.01). Because gamma-synuclein limits growth arrest and is implicated in cancer progression in nonadipocytes, we suspected that expression would be increased in situations where WAT plasticity/adipocyte turnover are engaged. Consistent with this postulate, human WAT gamma-synuclein mRNA levels consistently increased in obesity and were higher in SC than in VAT; i.e. they increased approximately 1.7-fold in obese Pima Indian adipocytes (P = 0.003) and approximately 2-fold in SC and VAT of other obese cohorts relative to nonobese subjects. Expression correlated with leptin transcript levels in human SC and VAT (r = 0.887; P < 0.0001; n = 44). Gamma-synuclein protein was observed in rodent and human WAT but not in negative control liver. These results are consistent with the hypothesis that gamma-synuclein plays an important role in adipocyte physiology.

Application of DNA microarray to the study of human adipose tissue/cells.

Adipose tissue is increasingly recognized as a metabolically active endocrine organ with multiple functions beyond its lipid storage capability. Various constituents of the tissue, such as mature adipocytes and stromal vascular cells, have distinct functions. For example, they express and secrete different kinds of bioactive molecules collectively called adipokines. Altered adipokine secretion patterns characterize obesity and insulin resistance, which are major risk factors for type 2 diabetes mellitus. The contribution of dysregulated adipokine expression to these diseases may be assembled from transcriptomic profiles of the tissue and/or its cellular constituents. The gene expression profiles may also complement genetic approaches to identify disease susceptibility genes. Here, we describe an application of gene expression profiling using DNA microarrays to study human adipose tissue, adipocytes, and stromal vascular cells.

Overweight and obesity in postpartum Hispanic women.

Overweight and obesity vary in prevalence among particular groups, and are especially problematic for childbearing Hispanic women. The complex interaction between physical changes associated with pregnancy, role changes accompanying birth, and family and cultural values related to childbearing are superimposed upon the underlying mechanisms that create or perpetuate obesity. In this article we review biological and behavioral research on obesity in postpartum Hispanic women to identify critical components for intervention studies focused on weight management. Recommendations are offered for health care providers and researchers.

Differential expression of matrix metalloproteinase 3 (MMP3) in preadipocytes/stromal vascular cells from nonobese nondiabetic versus obese nondiabetic Pima Indians.

Prior microarray studies comparing global gene expression patterns in preadipocytes/stromal vascular cells isolated from nonobese nondiabetic versus obese nondiabetic Pima Indians showed that matrix metalloproteinase 9 (MMP9) is upregulated in obese subjects. The current study targeted analysis of nine additional MMP genes that cluster to a region on chromosome 11q22 that is linked to BMI and percent body fat. Differential-display PCR showed that MMP3 is downregulated in preadipocytes/stromal vascular cells from obese subjects, and real-time PCR showed that MMP3 expression levels are negatively correlated with percent body fat. To determine whether variants within MMP3 are responsible for its altered expression, MMP3 was sequenced, and seven representative variants were genotyped in 1,037 Pima subjects for association analyses. Two variants were associated with both BMI and type 2 diabetes, and two additional variants were associated with type 2 diabetes alone; however, none of these variants were associated with MMP3 expression levels. We propose that the MMP3 pathway is altered in human obesity, but this alteration may be the result of a combination of genetic variation within the MMP3 locus itself, as well as variation in additional factors, either primary or secondary to obesity, that regulate expression of the MMP3 gene.

Regulation of protein degradation by insulin-degrading enzyme: analysis by small interfering RNA-mediated gene silencing.

Proteins are vital to the overall structure of cells and to the function of cells in the form of enzymes. Thus the control of protein metabolism is among the most important aspects of cellular metabolism. Insulin's major effect on protein metabolism in the adult animal is inhibition of protein degradation. This is via inhibition of proteasome activity via an interaction with insulin-degrading enzyme (IDE). IDE is responsible for the majority of cellular insulin degradation. We hypothesized that a reduction in IDE would reduce insulin degradation and insulin's ability to inhibit protein degradation. HepG2 cells were transfected with siRNA against human IDE and insulin degradation and protein degradation measured. Both IDE mRNA and protein were reduced by >50% in the IDE siRNA transfected cells. Insulin degradation was reduced by approximately 50%. Cells were labeled with [3H]-leucine to investigate protein degradation. Short-lived protein degradation was unchanged in the cells with reduced IDE expression. Long-lived and very-long-lived protein degradation was reduced in the cells with reduced IDE expression (14.0+/-0.16 vs. 12.5+/-0.07%/4h (long-lived), 9.6+/-2.2% vs. 7.3+/-0.2%/3h (very-long-lived), control vs. IDE transfected, respectively, P<0.005). The inhibition of protein degradation by insulin was reduced 37-76% by a decreased expression of IDE in HepG2 cells. This shows that IDE is involved in cellular insulin metabolism and provides further evidence that insulin inhibits protein degradation via an interaction with IDE.

Polymorphisms in the gene encoding 11B-hydroxysteroid dehydrogenase type 1 (HSD11B1) and lifetime cognitive change.

A rare polymorphism in the gene encoding 11B-hydroxysteroid dehydrogenase type 1 (HSD11B1: rs846911-C/A) has been associated with an increased risk of Alzheimer's disease. We tested the hypothesis that this and 2 other HSD11B1 polymorphisms (rs12086634-G/T and rs846910-A/G) were associated with lifetime cognitive change in humans. Subjects were 194 participants of the Scottish Mental Survey of 1932 who took the same well-validated mental test at age 11 and age 79. The subjects represented the highest and lowest quintiles with respect to cognitive decline between ages 11 and 79. Despite having non-significantly different IQs at age 11, by age 79 the groups had mean (S.D.) IQs of 80.3 (14.1) and 109.6 (9.1), respectively (p<.001). The polymorphism rs846911-C/A was absent from both groups. There were no significant differences in the frequency of polymorphisms of rs12086634-G/T (p=.91) and rs846910-A/G (p=.90) between the groups. We conclude that these variants in HSD11B1 are not significant contributors to the range of cognitive ageing examined here.

Polymorphisms in the oxygen-regulated protein 150 gene (ORP150) are associated with insulin resistance in Pima Indians.

The ORP150 gene that encodes the human oxygen-regulated protein (150 kDa) maps to chromosome 11q23, a region previously reported to be linked to type 2 diabetes and obesity in Pima Indians. This gene was also found to be differentially expressed in global gene expression studies comparing muscle mRNA from insulin-resistant versus insulin-sensitive subjects. Therefore, ORP150 was analyzed as a candidate gene for susceptibility to diabetes. Twelve variants were identified, and three unique representative polymorphisms were genotyped in 1,338 Pima Indians. None of these polymorphisms were associated with diabetes, but two polymorphisms were significantly associated with measures of insulin resistance. These data indicate that ORP150 has a role in insulin action but does not have a major role in determining susceptibility to type 2 diabetes in Pima Indians.

Metabolic effects of the Gly1057Asp polymorphism in IRS-2 and interactions with obesity.

Insulin receptor substrate (IRS)-2 plays an important role in insulin signaling and its disruption results in diabetes in mice. In humans, the IRS-2 Gly1057Asp substitution was associated with lower risk of type 2 diabetes in lean individuals, but with a higher risk in obese individuals. To clarify the role of IRS-2 on the development of type 2 diabetes and obesity in Pima Indians, and particularly to investigate whether the effects of the Gly1057Asp polymorphism on metabolism are mediated by obesity, molecular scanning of the gene for mutations was performed and interaction of the polymorphism with obesity was tested. We identified the previously described Gly1057Asp mutation as well as a rare Asp819His mutation and four silent polymorphisms. The effect of the Gly1057Asp mutation on type 2 diabetes and obesity was tested in a large cohort of Pima Indians (n = 998). A subgroup of nondiabetic full-heritage Pima Indians (n = 233) had measurements of body composition, glucose tolerance, insulin action (M), endogenous glucose production (EGP; hyperinsulinemic clamp), acute insulin response (AIR, 25-g intravenous glucose tolerance test, n = 118 normal glucose-tolerant subjects), and percutaneous fat biopsy specimens from the periumbilical region (n = 160). A total of 132 nondiabetic subjects were included in longitudinal analyses. The frequency of the Asp1057 allele was 0.6. In cross-sectional analyses, subjects homozygous for the Asp1057 allele (Asp/Asp) had a higher prevalence of type 2 diabetes than heterozygote individuals and subjects homozygous for the Gly1057 allele (X/Gly, P = 0.04). There was no effect on BMI (P = 0.78) or gene-BMI interaction on the prevalence of type 2 diabetes (P = 0.57). In the nondiabetic subgroup, subjects with Asp/Asp had higher percent body fat (P = 0.01), BMI (P = 0.02), and waist circumference (P = 0.004), but there was no difference in metabolic characteristics (all P > 0.2). However, the relationship between percent body fat and fasting glucose, basal EGP, EGP during the clamp, AIR, and subcutaneous abdominal adipocyte size was significantly different in the Asp/Asp group (P for interaction = 0.02, 0.06, 0.0007, 0.08, and 0.006, respectively) compared with the X/Gly group, suggesting a more detrimental effect of Asp homozygosity on these traits with increasing percent body fat. In longitudinal analyses, among subjects in the upper tertile of change in percent body fat, those with Asp/Asp had a larger increase in fasting and postprandial glycemia and basal EGP and a larger decrease in M and AIR than subjects with X/Gly, independent of change in obesity (all P < 0.05). In conclusion, our findings suggest that the association of homozygosity for the Asp1057 allele in IRS-2 with type 2 diabetes in Pima Indians may be mediated by interaction of the polymorphism with obesity on several diabetes-related traits.

The role of insulin receptor substrate-1 gene (IRS1) in type 2 diabetes in Pima Indians.

The insulin receptor substrate-1 (IRS1) is a critical element in insulin-signaling pathways, and mutations in the IRS1 gene have been reported to have a role in determining susceptibility to traits related to type 2 diabetes. In gene expression studies of tissue biopsies from nondiabetic Pima Indians, IRS1 mRNA levels were reduced in adipocytes from obese subjects compared with lean subjects, and IRS1 mRNA levels were also reduced in skeletal muscle from insulin-resistant subjects compared with insulin-sensitive subjects (all P < 0.05). Based on these expression differences and the known physiologic role of IRS1, this gene was investigated as a candidate gene for susceptibility to type 2 diabetes in Pima Indians, a population with an extremely high incidence and prevalence of type 2 diabetes. Thirteen variants were identified, and among these variants, several were in complete linkage disequilibrium. Four genotypically unique variants were further genotyped in 937 DNA samples from full-heritage Pima Indians. Three of the variants were modestly associated with type 2 diabetes (P < 0.05), one of which was additionally associated with 2-h plasma insulin and glucose as well as insulin action at physiologic and maximally stimulating insulin concentrations (all P < 0.05). The association of variants in IRS1 with type 2 diabetes and type 2 diabetes-related phenotypes and the differential expression of IRS1 in adipocytes and skeletal muscle suggest a role of this gene in the pathogenesis of type 2 diabetes in Pima Indians.

Subcutaneous adipose 11 beta-hydroxysteroid dehydrogenase type 1 activity and messenger ribonucleic acid levels are associated with adiposity and insulinemia in Pima Indians and Caucasians.

Metabolic effects of cortisol may be critically modulated by glucocorticoid metabolism in tissues. Specifically, active cortisol is regenerated from inactive cortisone by the enzyme 11 beta-hydroxysteroid dehydrogenase type 1 (11-HSD1) in adipose and liver. We examined activity and mRNA levels of 11-HSD1 and tissue cortisol and cortisone levels in sc adipose tissue biopsies from 12 Caucasian (7 males and 5 females) and 19 Pima Indian (10 males and 9 females) nondiabetic subjects aged 28 +/- 7.6 yr (mean +/- SD; range, 18-45). Adipose 11-HSD1 activity and mRNA levels were highly correlated (r = 0.51, P = 0.003). Adipose 11-HSD1 activity was positively related to measures of total (body mass index, percentage body fat) and central (waist circumference) adiposity (P < 0.05 for all) and fasting glucose (r = 0.43, P = 0.02), insulin (r = 0.60, P = 0.0005), and insulin resistance by the homeostasis model (r = 0.70, P < 0.0001) but did not differ between sexes or ethnic groups. Intra-adipose cortisol was positively associated with fasting insulin (r = 0.37, P = 0.04) but was not significantly correlated with 11-HSD1 mRNA or activity or with other metabolic variables. In this cross-sectional study, higher adipose 11-HSD1 activity is associated with features of the metabolic syndrome. Our data support the hypothesis that increased regeneration of cortisol in adipose tissue influences metabolic sequelae of human obesity.

Pioglitazone reduces inflammatory responses of human adipocytes to factors secreted by monocytes/macrophages.

Infiltration of monocyte-derived macrophages into adipose tissue may contribute to tissue and systemic inflammation and insulin resistance. We hypothesized that pioglitazone (Pio) could specifically reduce the inflammatory response of adipocytes to factors released by monocytes/macrophages. We show that macrophage factors (Mphi-factors) greatly increase expression levels of proinflammatory adipokines, chemokines, and adhesion molecules in human subcutaneous and visceral adipose tissue (SAT and VAT) as well as in adipocytes (up to several hundredfold of control). Compared with SAT, VAT showed enhanced basal and Mphi-factor-induced inflammatory responses. Mphi-factors also induced greater lipolysis in adipocytes, as assessed by concentrations of glycerol released from the cells (196 +/- 13 vs. 56 +/- 7 microM in control, P < 0.05). Pretreatment of adipose tissue or adipocytes with Pio reduced these responses to Mphi-factors (by 13-86%, P < 0.05) and prevented Mphi-factor suppression of adiponectin expression. Furthermore, Pio pretreatment of adipocytes and macrophages tended to further reduce inflammatory responses of adipocytes to Mphi-factors and monocyte adhesion to Mphi-factor-activated adipocytes. In support of these in vitro data, media conditioned by monocytes isolated from impaired glucose-tolerant subjects treated with Pio (compared with placebo) induced release of lower concentrations of proinflammatory adipokines and glycerol (100 +/- 7 vs. 150 +/- 15 microM, P < 0.05) from adipocytes. In summary, Pio decreases inflammatory responses in adipose tissue/cells induced by monocytes/macrophages by acting on either or both cell types. These beneficial effects of Pio may attenuate proinflammatory responses resulting from monocyte/macrophage infiltration into adipose tissue and suppress tissue inflammation resulting from the interaction between both cell types.

Amyloid precursor protein expression is upregulated in adipocytes in obesity.

The aim of this study was to determine whether amyloid precursor protein (APP) is expressed in human adipose tissue, dysregulated in obesity, and related to insulin resistance and inflammation. APP expression was examined by microarray expression profiling of subcutaneous abdominal adipocytes (SAC) and cultured preadipocytes from obese and nonobese subjects. Quantitative real-time PCR (QPCR) was performed to confirm differences in APP expression in SAC and to compare APP expression levels in adipose tissue, adipocytes, and stromal vascular cells (SVCs) from subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) specimens. Adipose tissue samples were also examined by western blot and immunofluorescence confocal microscopy. Microarray studies demonstrated that APP mRNA expression levels were higher in SAC (approximately 2.5-fold) and preadipocytes (approximately 1.4) from obese subjects. Real-time PCR confirmed increased APP expression in SAC in a separate group of obese compared with nonobese subjects (P=0.02). APP expression correlated to in vivo indices of insulin resistance independently of BMI and with the expression of proinflammatory genes, such as monocyte chemoattractant protein-1 (MCP-1) (R=0.62, P=0.004), macrophage inflammatory protein-1alpha (MIP-1alpha) (R=0.60, P=0.005), and interleukin-6 (IL-6) (R=0.71, P=0.0005). Full-length APP protein was detected in adipocytes by western blotting and APP and its cleavage peptides, Abeta40 and Abeta42, were observed in SAT and VAT by immunofluorescence confocal microscopy. In summary, APP is highly expressed in adipose tissue, upregulated in obesity, and expression levels correlate with insulin resistance and adipocyte cytokine expression levels. These data suggest a possible role for APP and/or Abeta in the development of obesity-related insulin resistance and adipose tissue inflammation.

Macrophage-secreted factors induce adipocyte inflammation and insulin resistance.

Macrophage infiltration into adipose tissue increases with obesity, a condition associated with low-grade inflammation and insulin resistance. We investigated the direct effects of macrophage-secreted factors on adipocyte inflammation and insulin resistance. 3T3-L1 adipocytes incubated with media conditioned by RAW264.7 macrophages (RAW-CM) showed dramatically increased transcription of several inflammation-related genes, greater nuclear factor kappa B (NF-kappaB) activity, and enhanced binding of U937 monocytes. All of these effects were prevented by co-incubation with pyrrolidinedithiocarbamate, an NF-kappaB inhibitor. Adipocytes incubated with RAW-CM also released more non-esterified fatty acids and this increased lipolysis was not suppressed by insulin. In addition, RAW-CM treatment decreased insulin-stimulated glucose uptake in adipocytes. Taken together, these results indicate that macrophage-secreted factors induce inflammatory responses and reduce insulin responsiveness in adipocytes. These effects of macrophage-secreted factors on adipocytes may contribute significantly to the systemic inflammation and insulin resistance associated with obesity.

11beta-hydroxysteroid dehydrogenase type 1 in adipose tissue and prospective changes in body weight and insulin resistance.

OBJECTIVE: Increased mRNA and activity levels of 11beta-hydroxysteroid dehydrogenase type 1 (11betaHSD1) in human adipose tissue (AT) are associated with obesity and insulin resistance. The aim of our study was to investigate whether 11betaHSD1 expression or activity in abdominal subcutaneous AT of non-diabetic subjects are associated with subsequent changes in body weight and insulin resistance [homeostasis model assessment of insulin resistance (HOMA-IR)]. RESEARCH METHODS AND PROCEDURES: Prospective analyses were performed in 20 subjects (two whites and 18 Pima Indians) who had baseline measurements of 11betaHSD1 mRNA and activity in whole AT (follow-up, 0.3 to 4.9 years) and in 47 Pima Indians who had baseline assessments of 11betaHSD1 mRNA in isolated adipocytes (follow-up, 0.8 to 5.3 years). RESULTS: In whole AT, although 11betaHSD1 mRNA levels showed positive associations with changes in weight and HOMA-IR, 11betaHSD1 activity was associated with changes in HOMA-IR but not in body weight. 11betaHSD1 mRNA levels in isolated adipocytes were not associated with follow-up changes in any of the anthropometric or metabolic variables. DISCUSSION: Our results indicate that increased expression of 11betaHSD1 in subcutaneous abdominal AT may contribute to risk of worsening obesity and insulin resistance. This prospective relationship does not seem to be mediated by increased 11betaHSD1 expression in adipocytes.

UCP5/BMCP1 transcript isoforms in human skeletal muscle: relationship of the short-insert isoform with lipid oxidation and resting metabolic rates.

Uncoupling protein 5 (UCP5) or brain mitochondrial carrier protein-1 (BMCP1) enhances mitochondrial proton leak in vitro and its hepatic and brain expression profiles are modulated by diet and cold exposure in mice. Alternative splicing generates three isoforms: a long form (UCP5L), a short form (UCP5S), and a short form with a 31 amino acid insert (UCP5SI). We investigated the relationship between skeletal muscle UCP5 expression and in vivo energy metabolism in 36 non-diabetic Pima Indians. We determined the expression levels of total UCP5 (UCP5T), and the isoforms UCP5L, UCP5S, and UCP5SI (66.8, 32.5, and 0.8% of UCP5T, respectively). None correlated with body weight or percent body fat. The transcript level of UCP5SI, but not the others, was positively correlated with resting metabolic rate (r=0.38, P=0.02, adjusted for age, sex, fat mass, and fat-free mass) and lipid oxidation rate (adjusted for age, sex, and percent body fat) during a euglycemic clamp with infusion of insulin at a physiologic concentration (r=0.42, P=0.01).