Effect of modernized collaborative care for depression on brain-derived neurotrophic factor (BDNF) and depressive symptom clusters: Data from the eIMPACT trial

Brain-derived neurotrophic factor (BDNF) levels are lower in people with depression and are normalized following pharmacological treatment. However, it is unknown if psychological treatments for depression improve BDNF and if change in BDNF is a mediator of intervention effects on depressive symptoms. Therefore, using data from the eIMPACT trial, we sought to determine the effect of modernized collaborative care for depression on 12-month changes in BDNF and cognitive/affective and somatic depressive symptom clusters and to examine whether BDNF changes mediate intervention effects on depressive symptoms. 216 primary care patients with depression from a safety net healthcare system were randomized to 12 months of the eIMPACT intervention (internet cognitive-behavioral therapy [CBT], telephonic CBT, and select antidepressant medications) or usual primary care. Plasma BDNF was measured with commercially available kits, and depressive symptom clusters were assessed by the Patient Health Questionnaire-9. The intervention did not influence BDNF but did improve both the cognitive/affective and somatic clusters over 12 months. Changes in BDNF did not mediate the intervention effect on either cluster. Our findings suggest that modernized collaborative care is an effective treatment for both the cognitive/affective and somatic symptoms of depression and that the mechanism of action is not improvements in BDNF. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02458690.

Effect of modernized collaborative care for depression on depressive symptoms and cardiovascular disease risk biomarkers: eIMPACT randomized controlled trial

Although depression is a risk and prognostic factor for cardiovascular disease (CVD), clinical trials treating depression in patients with CVD have not demonstrated cardiovascular benefits. We proposed a novel explanation for the null results for CVD-related outcomes: the late timing of depression treatment in the natural history of CVD. Our objective was to determine whether successful depression treatment before, versus after, clinical CVD onset reduces CVD risk in depression. We conducted a single-center, parallel-group, assessor-blinded randomized controlled trial. Primary care patients with depression and elevated CVD risk from a safety net healthcare system (N = 216, Mage = 59 years, 78% female, 50% Black, 46% with income <$10,000/year) were randomized to 12 months of the eIMPACT intervention (modernized collaborative care involving internet cognitive-behavioral therapy [CBT], telephonic CBT, and/or select antidepressants) or usual primary care for depression (primary care providers supported by embedded behavioral health clinicians and psychiatrists). Outcomes were depressive symptoms and CVD risk biomarkers at 12 months. Intervention participants, versus usual care participants, exhibited moderate-to-large (Hedges' g = -0.65, p < 0.01) improvements in depressive symptoms. Clinical response data yielded similar results - 43% of intervention participants, versus 17% of usual care participants, had a ≥ 50% reduction in depressive symptoms (OR = 3.73, 95% CI: 1.93-7.21, p < 0.01). However, no treatment group differences were observed for the CVD risk biomarkers - i.e., brachial flow-mediated dilation, high-frequency heart rate variability, interleukin-6, high-sensitivity C-reactive protein, β-thromboglobulin, and platelet factor 4 (Hedges' gs = -0.23 to 0.02, ps ≥ 0.09). Our modernized collaborative care intervention - which harnessed technology to maximize access and minimize resources - produced clinically meaningful improvements in depressive symptoms. However, successful depression treatment did not lower CVD risk biomarkers. Our findings indicate that depression treatment alone may not be sufficient to reduce the excess CVD risk of people with depression and that alternative approaches are needed. In addition, our effective intervention highlights the utility of eHealth interventions and centralized, remote treatment delivery in safety net clinical settings and could inform contemporary integrated care approaches. Trial Registration:ClinicalTrials.gov Identifier: NCT02458690.

A Reduced Pancreatic Polypeptide Response is Associated With New-onset Pancreatogenic Diabetes Versus Type 2 Diabetes

PURPOSE

Pancreatogenic diabetes refers to diabetes mellitus (DM) that develops in the setting of a disease of the exocrine pancreas, including pancreatic ductal adenocarcinoma (PDAC) and chronic pancreatitis (CP). We sought to evaluate whether a blunted nutrient response of pancreatic polypeptide (PP) can differentiate these DM subtypes from type 2 DM (T2DM).

METHODS

Subjects with new-onset DM (<3 years' duration) in the setting of PDAC (PDAC-DM, n = 28), CP (CP-DM, n = 38), or T2DM (n = 99) completed a standardized mixed meal tolerance test, then serum PP concentrations were subsequently measured at a central laboratory. Two-way comparisons of PP concentrations between groups were performed using Wilcoxon rank-sum test and analysis of covariance while adjusting for age, sex, and body mass index.

RESULTS

The fasting PP concentration was lower in both the PDAC-DM and CP-DM groups than in the T2DM group (P = 0.03 and <0.01, respectively). The fold change in PP at 15 minutes following meal stimulation was significantly lower in the PDAC-DM (median, 1.869) and CP-DM (1.813) groups compared with T2DM (3.283; P < 0.01 for both comparisons). The area under the curve of PP concentration was significantly lower in both the PDAC-DM and CP-DM groups than in T2DM regardless of the interval used for calculation and remained significant after adjustments.

CONCLUSIONS

Fasting PP concentrations and the response to meal stimulation are reduced in new-onset DM associated with PDAC or CP compared with T2DM. These findings support further investigations into the use of PP concentrations to characterize pancreatogenic DM and to understand the pathophysiological role in exocrine pancreatic diseases (NCT03460769).

Effect of changes in children's bedtime and sleep period on targeted eating behaviors and timing of caloric intake

Short sleep is associated with obesity risk. Experimental studies with adults and observational studies with children demonstrate that changes in eating, including increased caloric intake from energy-dense foods and sugar-sweetened beverages as well as increased caloric intake in the evening, may partially account for this increased risk. We therefore examined whether experimental changes in children's sleep period lead to changes in reported caloric intake from energy-dense snack foods and sugar-sweetened beverages, and in the evening. Thirty-seven children, 8-11 years old, completed a three-week study that used a within-subject randomized cross-over design. Children slept their typical amount for one week and were subsequently randomized to either increase or decrease their typical amount by 1.5 h/night for one week; the alternate schedule was completed during the third week of the study, creating a 3-h time in bed difference between the increase and decrease conditions. Sleep was monitored with actigraphy, and dietary intake was assessed with 24-hour dietary recalls. Participants reported consuming 35 kcal per day more from sugar-sweetened beverages during the decrease sleep than the increase sleep condition, p = .033. There were no reported differences between conditions from energy-dense snack foods. Although no differences in reported intake were observed earlier in the day, from 2000 h (8:00 PM) and later, children reported consuming 132 kcal more during the decrease sleep condition than the increase condition, p < 0.001. Shortened sleep achieved by delaying bedtimes led to increased caloric intake in the evening and from sugar-sweetened beverages. Clinical Trials Registration: clinicaltrials.gov Identifier: NCT01030107.

Saturated fat ingestion stimulates proatherogenic inflammation in polycystic ovary syndrome

Inflammation and dyslipidemia are often present in polycystic ovary syndrome (PCOS). We determined the effect of saturated fat ingestion on circulating heat shock protein-70 (HSP-70) and mononuclear cell (MNC) toll-like receptor-2 (TLR2) gene expression, activator protein-1 (AP-1) activation, and matrix matalloproteinase-2 (MMP-2) protein in women with PCOS. Twenty reproductive-age women with PCOS (10 lean, 10 with obesity) and 20 ovulatory controls (10 lean, 10 with obesity) participated in the study. HSP-70 was measured in serum and TLR2 mRNA and protein, AP-1 activation, and MMP-2 protein were quantified in MNC from blood drawn while fasting and 2, 3, and 5 h after saturated fat ingestion. Insulin sensitivity was derived from an oral glucose tolerance test (IS_OGTT). Androgen secretion was assessed from blood drawn while fasting and 24, 48, and 72 h after human chorionic gonadotropin (HCG) administration. In response to saturated fat ingestion, serum HSP-70, TLR2 gene expression, activated AP-1, and MMP-2 protein were greater in lean women with PCOS compared with lean controls and in women with PCOS and obesity compared with controls with obesity. Both PCOS groups exhibited lower IS_OGTT and greater HCG-stimulated androgen secretion compared with control subjects of their respective weight classes. Lipid-stimulated proatherogenic inflammation marker responses were negatively correlated with IS_OGTT and positively correlated with abdominal adiposity and HCG-stimulated androgen secretion. In PCOS, saturated fat ingestion stimulates proatherogenic inflammation independent of obesity. This effect is greater when PCOS is combined with obesity compared with obesity alone. Abdominal adiposity and hyperandrogenism may perpetuate proatherogenic inflammation.NEW & NOTEWORTHY This paper demonstrates that in polycystic ovary syndrome (PCOS), ingestion of saturated fat triggers a molecular pathway of inflammation known to drive atherogenesis. This effect is independent of obesity as it occurs in lean women with PCOS and not in lean ovulatory control subjects. Furthermore, the combined effects of PCOS and obesity are greater compared with obesity alone.

Inquiry into the short- and long-term effects of Roux-en-Y gastric bypass on the glomerular filtration rate

Bariatric surgery is known to attenuate glomerular hyperfiltration over the long term and thereby protect the kidney from mechanical damage. Whether this effect is directly related to weight loss or is independent of weight as are some of its other beneficial metabolic effects is not known. We explored this question in a preliminary study that directly measured glomerular filtration rate (GFR) before, immediately after, and again many months after Roux-en-Y gastric bypass after large weight loss had occurred. We simultaneously measured stimulated circulating glucagon-like peptide-1, which is upregulated after Roux-en-Y gastric bypass and is a putative mediator of GFR after bariatric surgery. We found no weight-independent effect of Roux-en-Y gastric bypass on GFR nor an association between circulating GLP-1 levels and GFR. These findings, if confirmed in larger studies, will help steer future enquiries in this area.

Lipid-induced mononuclear cell cytokine secretion in the development of metabolic aberration and androgen excess in polycystic ovary syndrome

STUDY QUESTION

What is the effect of saturated fat ingestion on mononuclear cell (MNC) TNFα, IL-6 and IL-1β secretion and circulating IL-6 levels in women with polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

Women with PCOS exhibit increases in MNC-derived TNFα, IL-6 and IL-1β secretion and circulating IL-6 following saturated fat ingestion even in the absence of obesity, and these increases are linked to metabolic aberration and androgen excess.

WHAT IS KNOWN ALREADY

Cytokine excess and metabolic aberration is often present in PCOS.

STUDY DESIGN, SIZE, DURATION

A cross-sectional design was used in this study of 38 reproductive-age women.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Groups of 19 reproductive-age women with PCOS (10 lean, 9 obese) and 19 ovulatory controls (10 lean, 9 obese) participated in this study that was performed at a tertiary academic medical centre. TNFα, IL-6 and IL-1β secretion was measured from cultured MNC, and IL-6 was measured in plasma from blood sampling while fasting and 2, 3 and 5 h after saturated fat ingestion. Insulin sensitivity was determined using the Matsuda index following an oral glucose tolerance test. Androgen secretion was evaluated with blood sampling while fasting and 24, 48 and 72 h after an HCG injection.

MAIN RESULTS AND THE ROLE OF CHANCE

Lean and obese women with PCOS exhibited lipid-induced incremental AUC increases in MNC-derived TNFα (489-611%), IL-6 (333-398%) and IL-1β (560-695%) secretion and in plasma IL-6 levels (426-474%), in contrast with lean control subjects. In both PCOS groups, insulin sensitivity was lower (42-49%) and androgen secretion after HCG injection was greater (63-110%) compared with control subjects. The MNC-derived TNFα, IL-6 and IL-1β and circulating IL-6 responses were inversely associated with insulin sensitivity and directly associated with fasting lipids and androgen secretion after HCG injection.

LIMITATIONS, REASONS FOR CAUTION

The sample size of each of the four study groups was modest following group assignment of subjects by body mass.

WIDER IMPLICATIONS OF THE FINDINGS

This study showcases the unique pro-inflammatory contribution of circulating MNC in the development of metabolic aberration and androgen excess in PCOS.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by grant R01 DK107605 to F.G. from the National Institutes of Health, the Indiana Clinical and Translational Sciences Institute Clinical Research Center which is funded in part by grant UL1TR002529 from the National Institutes of Health, National Center for Advancing Translational Sciences, Clinical and Translational Sciences Award, and the Indiana University Center for Diabetes and Metabolic Diseases funded by grant P30 DK097512 from the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. No conflicts of interest, financial or otherwise, are declared by the authors.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT01489319.

The linearized disposition index augments understanding of treatment effects in diabetes

The disposition index, calculated by multiplying measures of insulin secretion and insulin sensitivity, is widely applied as a sensitivity-adjusted measure of insulin secretion. We have recently shown that linearizing the underlying relationship uniquely permits identification of terms relating to maximal insulin secretion capacity and the secretion-coupling relationship, with both terms separately contributing to differences in the secretion-sensitivity relationship across gradations of glycemia. Here, we demonstrate the application of this linearized equation to the evaluation of treatment-induced changes in the insulin secretion-sensitivity relationship. We applied a combination of repeated-measures multivariate linear regression (evaluating treatment-induced changes in the joint relationship of insulin sensitivity and secretion) plus mixed-model repeated measures (evaluating treatment effects on maximal secretion capacity and on the secretion-sensitivity coupling slope) and compared against a usual application of the disposition index calculated from the same measurements. This novel approach allows a more informative description of treatment-induced changes compared with the usual disposition index, including isolating the source of change within the mutually adjusted relationship and identifying treatment-induced changes in the secretion-sensitivity coupling slope and in maximal insulin secretion. Application of this linearized approach provides an expanded understanding of treatment-induced changes in the insulin sensitivity-secretion relationship.NEW & NOTEWORTHY The linearized insulin secretion-sensitivity relationship allows separate evaluation of the secretion-sensitivity slope and of maximal insulin secretion. Here, we demonstrate the application of this methodology to the evaluation of clinical trial data, showing that it provides an expanded understanding of treatment-induced changes compared with the disposition index.

Salicylate administration suppresses the inflammatory response to nutrients and improves ovarian function in polycystic ovary syndrome

Oxidative stress (OS) and inflammation are often present in polycystic ovary syndrome (PCOS). We examined the effects of salsalate treatment on nutrient-induced OS and inflammation, ovarian androgen secretion, ovulation, and insulin sensitivity in PCOS. Eight lean insulin-sensitive women with PCOS and eight age- and body composition-matched ovulatory controls for baseline comparison participated in the study. The women with PCOS underwent a 12-wk treatment of salsalate, a nonsteroidal anti-inflammatory drug, at a dose of 3 g daily. Markers of OS and inflammation were quantified in mononuclear cells (MNC) and plasma from blood drawn fasting and 2 h after saturated fat ingestion before and after treatment. Ovarian androgen secretion was assessed from blood drawn fasting and 24, 48, and 72 h after human chorionic gonadotropin (HCG) administration before and after treatment. Ovulation was documented based on biphasic basal body temperatures and luteal range progesterone elevations. A two-step pancreatic clamp was performed pre- and posttreatment to measure basal endogenous glucose production (EGP) and the steady-state glucose disposal rate (GDR) during the euglycemic phase and markers of OS and inflammation in MNC and plasma during the hyperglycemic phase. Salsalate administration suppressed lipid- and glucose-stimulated reactive oxygen species generation, activated nuclear factor-κB and circulating tumor necrosis factor-α, normalized basal androgen levels, and lowered HCG-stimulated androgen secretion without altering EGP or GDR. Four salsalate-treated subjects responded with two consecutive ovulations. We conclude that in PCOS, salsalate-induced suppression of OS and inflammation ameliorates ovarian androgen hypersecretion and may induce ovulation while maintaining insulin action.

Oligomeric collagen as an encapsulation material for islet/β-cell replacement: effect of islet source, dose, implant site, and administration format

Replacement of islets/β-cells that provide long-lasting glucose-sensing and insulin-releasing functions has the potential to restore extended glycemic control in individuals with type 1 diabetes. Unfortunately, persistent challenges preclude such therapies from widespread clinical use, including cumbersome administration via portal vein infusion, significant loss of functional islet mass upon administration, limited functional longevity, and requirement for systemic immunosuppression. Previously, fibril-forming type I collagen (oligomer) was shown to support subcutaneous injection and in situ encapsulation of syngeneic islets within diabetic mice, with rapid (<24 h) reversal of hyperglycemia and maintenance of euglycemia for beyond 90 days. Here, we further evaluated this macroencapsulation strategy, defining effects of islet source (allogeneic and xenogeneic) and dose (500 and 800 islets), injection microenvironment (subcutaneous and intraperitoneal), and macrocapsule format (injectable and preformed implantable) on islet functional longevity and recipient immune response. We found that xenogeneic rat islets functioned similarly to or better than allogeneic mouse islets, with only modest improvements in longevity noted with dosage. Additionally, subcutaneous injection led to more consistent encapsulation outcomes along with improved islet health and longevity, compared with intraperitoneal administration, whereas no significant differences were observed between subcutaneous injectable and preformed implantable formats. Collectively, these results document the benefits of incorporating natural collagen for islet/β-cell replacement therapies.

Inflammation Triggered by Saturated Fat Ingestion Is Linked to Insulin Resistance and Hyperandrogenism in Polycystic Ovary Syndrome

CONTEXT

Inflammation and insulin resistance are often present in polycystic ovary syndrome (PCOS).

OBJECTIVE

We determined the effect of saturated fat ingestion on mononuclear cell (MNC) nuclear factor-κB (NFκB) activation; NFκB, inhibitory-κBα (IκBα), and tumor necrosis factor-α (TNFα) gene expression; and circulating C-reactive protein (CRP) in women with PCOS.

DESIGN

Cross-sectional study.

SETTING

Academic medical center.

PATIENTS

Twenty reproductive-age women with PCOS (10 lean, 10 with obesity) and 20 ovulatory controls (10 lean, 10 with obesity).

MAIN OUTCOME MEASURES

Activated NFκB, NFκB heterodimer subunits, IκBα and TNFα messenger ribonucleic acid content and NFκB p65 and IκBα protein content were quantified in mononuclear cells (MNC), and CRP was measured in plasma from blood drawn fasting and 2, 3, and 5 h after saturated fat ingestion. Insulin sensitivity was derived from oral glucose tolerance testing (ISOGTT). Androgen secretion was assessed from blood drawn fasting and 24, 48, and 72 h after human chorionic gonadotropin (HCG) administration.

RESULTS

In response to saturated fat ingestion, women with PCOS regardless of weight class exhibited lipid-induced increases in activated NFκB, NFκB, and TNFα gene expression and plasma CRP and decreases in IκBα protein compared with lean control subjects. Both PCOS groups exhibited lower ISOGTT and greater HCG-stimulated androgen secretion compared with control subjects. Lipid-stimulated NFκB activation was negatively correlated with ISOGTT, and positively correlated with HCG-stimulated androgen secretion.

CONCLUSION

In PCOS, increases in NFκB activation and circulating CRP and decreases in IκBα protein following saturated fat ingestion are independent of obesity. Circulating MNC and excess adipose tissue are separate and distinct contributors to inflammation in this disorder.

Treatment With Treprostinil and Metformin Normalizes Hyperglycemia and Improves Cardiac Function in Pulmonary Hypertension Associated With Heart Failure With Preserved Ejection Fraction

OBJECTIVE

Pulmonary hypertension (PH) due to left heart disease (group 2), especially in the setting of heart failure with preserved ejection fraction (HFpEF), is the most common cause of PH worldwide; however, at present, there is no proven effective therapy available for its treatment. PH-HFpEF is associated with insulin resistance and features of metabolic syndrome. The stable prostacyclin analog, treprostinil, is an effective and widely used Food and Drug Administration-approved drug for the treatment of pulmonary arterial hypertension. While the effect of treprostinil on metabolic syndrome is unknown, a recent study suggests that the prostacyclin analog beraprost can improve glucose intolerance and insulin sensitivity. We sought to evaluate the effectiveness of treprostinil in the treatment of metabolic syndrome-associated PH-HFpEF. Approach and Results: Treprostinil treatment was given to mice with mild metabolic syndrome-associated PH-HFpEF induced by high-fat diet and to SU5416/obese ZSF1 rats, a model created by the treatment of rats with a more profound metabolic syndrome due to double leptin receptor defect (obese ZSF1) with a vascular endothelial growth factor receptor blocker SU5416. In high-fat diet-exposed mice, chronic treatment with treprostinil reduced hyperglycemia and pulmonary hypertension. In SU5416/Obese ZSF1 rats, treprostinil improved hyperglycemia with similar efficacy to that of metformin (a first-line drug for type 2 diabetes mellitus); the glucose-lowering effect of treprostinil was further potentiated by the combined treatment with metformin. Early treatment with treprostinil in SU5416/Obese ZSF1 rats lowered pulmonary pressures, and a late treatment with treprostinil together with metformin improved pulmonary artery acceleration time to ejection time ratio and tricuspid annular plane systolic excursion with AMPK (AMP-activated protein kinase) activation in skeletal muscle and the right ventricle.

CONCLUSIONS

Our data suggest a potential use of treprostinil as an early treatment for mild metabolic syndrome-associated PH-HFpEF and that combined treatment with treprostinil and metformin may improve hyperglycemia and cardiac function in a more severe disease.

Oxidative Stress in Response to Saturated Fat Ingestion Is Linked to Insulin Resistance and Hyperandrogenism in Polycystic Ovary Syndrome

CONTEXT

Oxidative stress and insulin resistance are often present in polycystic ovary syndrome (PCOS).

OBJECTIVE

We determined the effect of saturated fat ingestion on leukocytic reactive oxygen species (ROS) generation, p47phox expression, and circulating thiobarbituric acid-reactive substances (TBARS) in women with PCOS.

DESIGN

Cross-sectional study.

SETTING

Academic medical center.

PATIENTS

Twenty women of reproductive age with PCOS (10 lean, 10 with obesity) and 19 ovulatory control subjects (10 lean, 9 with obesity).

MAIN OUTCOME MEASURES

ROS generation and p47phox mRNA and protein content were quantified in leukocytes, and TBARS was measured in plasma from blood drawn while the subjects were fasting and 2, 3, and 5 hours after saturated fat ingestion. Insulin sensitivity was derived from an oral glucose tolerance test (ISOGTT). Androgen secretion was assessed from blood drawn while the subjects were fasting and 24, 48, and 72 hours after human chorionic gonadotropin (HCG) administration.

RESULTS

Regardless of weight class, women with PCOS exhibited lipid-induced increases in leukocytic ROS generation and p47phox mRNA and protein content as well as plasma TBARS compared with lean control subjects. Both PCOS groups exhibited lower ISOGTT and greater HCG-stimulated androgen secretion compared with control subjects. The ROS generation, p47phox, and TBARS responses were negatively correlated with ISOGTT and positively correlated with HCG-stimulated androgen secretion.

CONCLUSION

In PCOS, increases in ROS generation, p47phox gene expression, and circulating TBARS in response to saturated fat ingestion are independent of obesity. Circulating mononuclear cells and excess adipose tissue are separate and distinct contributors to oxidative stress in this disorder.

MIND food and speed of processing training in older adults with low education, the MINDSpeed Alzheimer's disease prevention pilot trial

BACKGROUND

Multiple national organizations and leaders have called for increased attention to dementia prevention in those most vulnerable, for example persons with limited formal education. Prevention recommendations have included calls for multicomponent interventions that have the potential to improve both underlying neurobiological health and the ability to function despite neurobiological pathology, or what has been termed cognitive reserve.

OBJECTIVES

Test feasibility, treatment modifier, mechanism, and cognitive function effects of a multicomponent intervention consisting of foods high in polyphenols (i.e., MIND foods) to target neurobiological health, and speed of processing training to enhance cognitive reserve. We refer to this multicomponent intervention as MINDSpeed.

DESIGN

MINDSpeed is being evaluated in a 2 × 2 randomized factorial design with 180 participants residing independently in a large Midwestern city. Qualifying participants are 60 years of age or older with no evidence of dementia, and who have completed 12 years or less of education. All participants receive a study-issued iPad to access the custom study application that enables participants, depending on randomization, to select either control or MIND food, and to play online cognitive games, either speed of processing or control games.

METHODS

All participants complete informed consent and baseline assessment, including urine and blood samples. Additionally, up to 90 participants will complete neuroimaging. Assessments are repeated immediately following 12 weeks of active intervention, and at 24 weeks post-randomization. The primary outcome is an executive cognitive composite score. Secondary outcomes include oxidative stress, pro-inflammatory cytokines, and neuroimaging-captured structural and functional metrics of the hippocampus and cortical brain regions.

SUMMARY

MINDSpeed is the first study to evaluate the multicomponent intervention of high polyphenol intake and speed of processing training. It is also one of the first dementia prevention trials to target older adults with low education. The results of the study will guide future dementia prevention efforts and trials in high risk populations.

Saturated Fat Ingestion Promotes Lipopolysaccharide-Mediated Inflammation and Insulin Resistance in Polycystic Ovary Syndrome

Context

Inflammation and insulin resistance (IR) are often present in polycystic ovary syndrome (PCOS).

Objective

We determined the effect of saturated fat ingestion on circulating lipopolysaccharide (LPS) and mononuclear cell (MNC) toll-like receptor-4 (TLR-4) and suppressor of cytokine signaling-3 (SOCS-3) in women with PCOS.

Design

Cross-sectional study.

Setting

Academic medical center.

Patients

Nineteen reproductive-age women with PCOS (10 lean, 9 obese) and 19 ovulatory control subjects (10 lean, 9 obese).

Main Outcome Measures

LPS and TNFα levels were measured in plasma. TLR-4 and SOCS-3 mRNA and protein content were quantified in MNC from blood collected after fasting and 2, 3, and 5 hours after saturated fat ingestion. Insulin sensitivity was derived from an oral glucose tolerance test (ISOGTT). Androgen secretion was assessed from blood collected after fasting and 24, 48, and 72 hours after human chorionic gonadotropin (HCG) administration.

Results

Regardless of PCOS status, subjects who were obese had lipid-induced increases in circulating LPS and TLR-4 protein content compared with subjects who were lean. Lean and obese women with PCOS had lipid-induced increases in plasma TNFα and SOCS-3 mRNA and protein content compared with lean control subjects. Both PCOS groups had lower ISOGTT and greater HCG-stimulated androgen secretion compared with control subjects. The LPS and SOCS-3 responses were negatively correlated with ISOGTT and positively correlated with HCG-stimulated androgen secretion.

Conclusion

In PCOS, lipid-induced LPS-mediated inflammation through TLR-4 is associated with obesity and worsened by PCOS, whereas lipid-induced increases in SOCS-3 may represent an obesity-independent, TNFα-mediated mechanism of IR.

Proinsulin Secretion Is a Persistent Feature of Type 1 Diabetes

OBJECTIVE

Abnormally elevated proinsulin secretion has been reported in type 2 and early type 1 diabetes when significant C-peptide is present. We questioned whether individuals with long-standing type 1 diabetes and low or absent C-peptide secretory capacity retained the ability to make proinsulin.

RESEARCH DESIGN AND METHODS

C-peptide and proinsulin were measured in fasting and stimulated sera from 319 subjects with long-standing type 1 diabetes (≥3 years) and 12 control subjects without diabetes. We considered three categories of stimulated C-peptide: 1) C-peptide positive, with high stimulated values ≥0.2 nmol/L; 2) C-peptide positive, with low stimulated values ≥0.017 but <0.2 nmol/L; and 3) C-peptide <0.017 nmol/L. Longitudinal samples were analyzed from C-peptide-positive subjects with diabetes after 1, 2, and 4 years.

RESULTS

Of individuals with long-standing type 1 diabetes, 95.9% had detectable serum proinsulin (>3.1 pmol/L), while 89.9% of participants with stimulated C-peptide values below the limit of detection (<0.017 nmol/L; n = 99) had measurable proinsulin. Proinsulin levels remained stable over 4 years of follow-up, while C-peptide decreased slowly during longitudinal analysis. Correlations between proinsulin with C-peptide and mixed-meal stimulation of proinsulin were found only in subjects with high stimulated C-peptide values (≥0.2 nmol/L). Specifically, increases in proinsulin with mixed-meal stimulation were present only in the group with high stimulated C-peptide values, with no increases observed among subjects with low or undetectable (<0.017 nmol/L) residual C-peptide.

CONCLUSIONS

In individuals with long-duration type 1 diabetes, the ability to secrete proinsulin persists, even in those with undetectable serum C-peptide.

In situ type I oligomeric collagen macroencapsulation promotes islet longevity and function in vitro and in vivo

Widespread use of pancreatic islet transplantation for treatment of type 1 diabetes (T1D) is currently limited by requirements for long-term immunosuppression, limited donor supply, and poor long-term engraftment and function. Upon isolation from their native microenvironment, islets undergo rapid apoptosis, which is further exacerbated by poor oxygen and nutrient supply following infusion into the portal vein. Identifying alternative strategies to restore critical microenvironmental cues, while maximizing islet health and function, is needed to advance this cellular therapy. We hypothesized that biophysical properties provided through type I oligomeric collagen macroencapsulation are important considerations when designing strategies to improve islet survival, phenotype, and function. Mouse islets were encapsulated at various Oligomer concentrations (0.5 -3.0 mg/ml) or suspended in media and cultured for 14 days, after which viability, protein expression, and function were assessed. Oligomer-encapsulated islets showed a density-dependent improvement in in vitro viability, cytoarchitecture, and insulin secretion, with 3 mg/ml yielding values comparable to freshly isolated islets. For transplantation into streptozotocin-induced diabetic mice, 500 islets were mixed in Oligomer and injected subcutaneously, where rapid in situ macroencapsulation occurred, or injected with saline. Mice treated with Oligomer-encapsulated islets exhibited rapid (within 24 h) diabetes reversal and maintenance of normoglycemia for 14 (immunocompromised), 90 (syngeneic), and 40 days (allogeneic). Histological analysis showed Oligomer-islet engraftment with maintenance of islet cytoarchitecture, revascularization, and no foreign body response. Oligomer-islet macroencapsulation may provide a useful strategy for prolonging the health and function of cultured islets and has potential as a subcutaneous injectable islet transplantation strategy for treatment of T1D.

Combination GLP-1 and Insulin Treatment Fails to Alter Myocardial Fuel Selection vs. Insulin Alone in Type 2 Diabetes

CONTEXT

It is unclear if effects of glucagon-like peptide-1 (GLP-1) and clinically available GLP-1 agonists on the heart occur at clinical doses in humans, possibly contributing to reduced cardiovascular disease risk.

OBJECTIVE

To determine whether liraglutide, at clinical dosing, augments myocardial glucose uptake (MGU) alone or combined with insulin compared with insulin alone in metformin-treated type 2 diabetes mellitus (T2D).

DESIGN

In a randomized clinical trial of patients with T2D treated with metformin plus oral agents or basal insulin, myocardial fuel use was compared after 3 months of treatment with insulin detemir, liraglutide, or combination detemir plus liraglutide added to background metformin.

MAIN OUTCOME MEASURES

Myocardial blood flow (MBF), fuel selection, and rates of fuel use were evaluated using positron emission tomography, powered to demonstrate large effects.

RESULTS

MBF was greater in the insulin-treated groups [median (25th, 75th percentile): detemir, 0.64 mL/g/min (0.50, 0.69); liraglutide, 0.52 mL/g/min (0.46, 0.58); detemir plus liraglutide, 0.75 mL/g/min (0.55, 0.77); P = 0.035 comparing three groups, P = 0.01 comparing detemir groups to liraglutide alone]. There were no evident differences among groups in MGU [detemir, 0.040 µmol/g/min (0.013, 0.049); liraglutide, 0.055 µmol/g/min (0.019, 0.105); detemir plus liraglutide, 0.037 µmol/g/min (0.009, 0.046); P = 0.68 comparing three groups]. There were no treatment-group differences in measures of myocardial fatty acid uptake or handling, and no differences in total oxidation rate.

CONCLUSION

These observations argue against large effects of GLP-1 agonists on myocardial fuel metabolism as mediators of beneficial treatment effects on myocardial function and ischemia protection.

Aspartame Consumption for 12 Weeks Does Not Affect Glycemia, Appetite, or Body Weight of Healthy, Lean Adults in a Randomized Controlled Trial

Background

Low-calorie sweeteners are often used to moderate energy intake and postprandial glycemia, but some evidence indicates that they may exacerbate these aims.

Objective

The trial's primary aim was to assess the effect of daily aspartame ingestion for 12 wk on glycemia. Effects on appetite and body weight were secondary aims.

Methods

One hundred lean [body mass index (kg/m2): 18-25] adults aged 18-60 y were randomly assigned to consume 0, 350, or 1050 mg aspartame/d (ASP groups) in a beverage for 12 wk in a parallel-arm design. At baseline, body weight and composition were determined, a 240-min oral-glucose-tolerance test (OGTT) was administered, and measurements were made of appetite and selected hormones. Participants also collected a 24-h urine sample. During the intervention, the 0-mg/d ASP group consumed capsules containing 680 mg dextrose and 80 mg para-amino benzoic acid. For the 350-mg/d ASP group, the beverage contained 350 mg aspartame and the 1050-mg/d ASP group consumed the same beverage plus capsules containing 680 mg dextrose and 700 mg aspartame. Body weight, blood pressure, heart rate, and waist circumference were measured weekly. At weeks 4, 8, and 12, participants collected 24-h urine samples and kept appetite logs. Baseline measurements were repeated at week 12.

Results

With the exception of the baseline OGTT glucose concentration at 60 min (and resulting area under the curve value), there were no group differences for glucose, insulin, resting leptin, glucagon-like peptide 1, or gastric inhibitory peptide at baseline or week 12. There also were no effects of aspartame ingestion on appetite, body weight, or body composition. Compliance with the beverage intervention was ∼95%.

Conclusions

Aspartame ingested at 2 doses for 12 wk had no effect on glycemia, appetite, or body weight among healthy, lean adults. These data do not support the view that aspartame is problematic for the management of glycemia, appetite, or body weight. This trial was registered at www.clinicaltrials.gov as NCT02999321.

Comparison of β-Cell Function Between Overweight/Obese Adults and Adolescents Across the Spectrum of Glycemia

OBJECTIVE

Type 2 diabetes is a growing health problem among both adults and adolescents. To better understand the differences in the pathogenesis of diabetes between these groups, we examined differences in β-cell function along the spectrum of glucose tolerance.

RESEARCH DESIGN AND METHODS

We evaluated 89 adults and 50 adolescents with normal glucose tolerance (NGT), dysglycemia, or type 2 diabetes. Oral glucose tolerance test results were used for C-peptide and insulin/glucose minimal modeling. Model-derived and direct measures of insulin secretion and insulin sensitivity were compared across glycemic stages and between age-groups at each stage.

RESULTS

In adolescents with dysglycemia, there was marked insulin resistance (insulin sensitivity index: adolescents, median [interquartile range] 1.8 [1.1-2.4] × 10^-4; adults, 5.0 [2.3-9.9]; P = 0.01). The nature of β-cell dysfunction across stages of dysglycemia differed between the groups. We observed higher levels of secretion among adolescents than adults (total insulin secretion: NGT, 143 [103-284] × 10^-9/min adolescent vs. 106 [71-127], P = 0.001); adults showed stepwise impairments in static insulin secretion (NGT, 7.5 [4.0-10.3] × 10^-9/min; dysglycemia, 5.0 [2.3-9.9]; type 2 diabetes, 0.7 [0.1-2.45]; P = 0.003), whereas adolescents showed diabetes-related impairment in dynamic secretion (NGT, 1,905 [1,630-3,913] × 10^-9; dysglycemia, 2,703 [1,323-3,637]; type 2 diabetes, 1,189 [269-1,410]; P = 0.001).

CONCLUSIONS

Adults and adolescents differ in the underlying defects leading to dysglycemia, and in the nature of β-cell dysfunction across stages of dysglycemia. These results may suggest different approaches to diabetes prevention in youths versus adults.

Family history of alcoholism and the human brain response to oral sucrose

A heightened hedonic response to sweet tastes has been associated with increased alcohol preference and alcohol consumption in both humans and animals. The principal goal of this study was to examine blood oxygenation level dependent (BOLD) activation to high- and low-concentration sweet solutions in subjects who are either positive (FHP) or negative (FHN) for a family history of alcoholism. Seventy-four non-treatment seeking, community-recruited, healthy volunteers (22.8 ± 1.6 SD years; 43% men) rated a range of sucrose concentrations in a taste test and underwent functional magnetic resonance imaging (fMRI) during oral delivery of water, 0.83 M, and 0.10 M sucrose. Sucrose compared to water produced robust activation in primary gustatory cortex, ventral insula, amygdala, and ventral striatum. FHP subjects displayed greater bilateral amygdala activation than FHN subjects in the low sucrose concentration (0.10 M). In secondary analyses, the right amygdala response to the 0.10 M sucrose was greatest in FHP women. When accounting for group differences in drinks per week, the family history groups remained significantly different in their right amygdala response to 0.10 M sucrose. Our findings suggest that the brain response to oral sucrose differs with a family history of alcoholism, and that this response to a mildly reinforcing primary reward might be an endophenotypic marker of alcoholism risk.

•

Studies in humans and animals have suggested sweet tastes as a trait correlate of alcohol risk.

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Oral sucrose resulted in robust BOLD activation of gustatory and limbic areas.

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Amygdala responses to 0.10 M sucrose were greatest in drinkers with family histories of alcoholism.

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This study is first to suggest endophenotypic brain responses to sucrose in familial alcoholism.

Metabolic improvements following Roux-en-Y surgery assessed by solid meal test in subjects with short duration type 2 diabetes

BACKGROUND

Glucose homeostasis improves within days following Roux-en-Y gastric bypass (RYGB) surgery. The dynamic metabolic response to caloric intake following RYGB has been assessed using liquid mixed meal tolerance tests (MMTT). Few studies have evaluated the glycemic and hormonal response to a solid mixed meal in subjects with diabetes prior to, and within the first month following RYGB.

METHODS

Seventeen women with type 2 diabetes of less than 5 years duration participated. Fasting measures of glucose homeostasis, lipids and gut hormones were obtained pre- and post-surgery. MMTT utilizing a solid 4 oz chocolate pudding performed pre-, 2 and 4 weeks post-surgery. Metabolic response to 4 and 2 oz MMTT assessed in five diabetic subjects not undergoing surgery.

RESULTS

Significant reductions in fasting glucose and insulin at 3 days, and in fasting betatrophin, triglycerides and total cholesterol at 2 weeks post-surgery. Hepatic insulin clearance was greater at 3 days post-surgery. Subjects exhibited less hunger and greater feelings of fullness and satisfaction during the MMTT while consuming 52.9 ± 6.5% and 51.0 ± 6.5% of the meal at 2 and 4 weeks post-surgery respectively. At 2 weeks post-surgery, glucose and insulin response to MMTT were improved, with greater GLP-1 and PYY secretion. Improved response to solid MMTT not replicated by consumption of smaller pudding volume in diabetic non-surgical subjects.

CONCLUSIONS

With a test meal of size and composition representative of the routine diet of post-RYGB subjects, improved glycemic and gut hormone responses occur which cannot be replicated by reducing the size of the MMTT in diabetic subjects not undergoing surgery.

TRIAL REGISTRATION

Clinical Trials.gov Identifier: NCT00957957 August 11, 2009.

Retinopathy predicts progression of fasting plasma glucose: An Early Diabetes Intervention Program (EDIP) analysis

BACKGROUND

Retinopathy is increasingly recognized in prediabetic populations, and may herald increased risk of metabolic worsening. The Early Diabetes Intervention Program (EDIP) evaluated worsening of glycemia in screen-detected Type 2 diabetes, following participants for up to 5years. Here we have evaluated whether the presence of retinopathy at the time of detection of diabetes was associated with accelerated progression of glycemia.

METHODS

We prospectively studied 194 participants from EDIP with available baseline retinal photographs. Retinopathy was determined at baseline using 7-field fundus photography and defined as an Early Treatment of Diabetic Retinopathy Study Scale grading score of ≥20.

RESULTS

At baseline, 12% of participants had classical retinal lesions indicating retinopathy. In univariate Cox proportional hazard analysis, the presence of retinopathy at baseline was associated with a doubled risk of progression of fasting plasma glucose (HR 2.02; 95% CI 1.05-3.89). The retinopathy effect was robust to individual adjustment for age and glucose, the most potent determinants of progression in EDIP.

CONCLUSION

Retinopathy was associated with increased risk of progression of fasting plasma glucose among adults with screen-detected, early diabetes. Early detection of retinopathy may help individualize more aggressive therapy to prevent progressive metabolic worsening in early diabetes.

Changes in Weight and Glucose Can Protect Against Progression in Early Diabetes Independent of Improvements in β-Cell Function

CONTEXT

Evidence-based strategies to prevent progression of dysglycemia in newly diagnosed type 2 diabetes are needed.

OBJECTIVE

To undertake a secondary analysis of the Early Diabetes Intervention Program (EDIP) in order to understand the features that were protective against worsening glycemia.

DESIGN

EDIP was a randomized, placebo-controlled trial.

SETTING

Two university diabetes centers.

PATIENTS

A total of 219 overweight individuals with fasting glucose < 7.8 mmol/L and 2-hour oral glucose tolerance test (OGTT) glucose > 11.1 mmol/L.

INTERVENTIONS

Acarbose versus placebo, on a background of dietary recommendations, with quarterly visits to assess glycemia and intervention adherence for up to 5 years.

MAIN OUTCOME MEASURES

Progression of fasting glucose ≥ 7.8 mmol/L on two consecutive quarterly visits. Cox proportional hazards modeling and ANOVA were performed to evaluate determinants of progression.

RESULTS

Progression-free status was associated with reductions in weight, fasting glucose, 2-hour OGTT glucose, and increases in the high-density lipoprotein/triglyceride ratio. The reduction in fasting glucose was the only effect that remained significantly associated with progression-free status in multivariable Cox modeling. The reduction in fasting glucose was in turn primarily associated with reductions in weight and in 2-hour OGTT glucose. Acarbose treatment did not explain these changes.

CONCLUSIONS

In early diabetes, reductions in glucose, driven by reductions in weight, can delay progressive metabolic worsening. These observations underscore the importance of lifestyle management including weight loss as a tool to mitigate worsening of glycemia in newly diagnosed diabetes.

Assessment of myocardial metabolic flexibility and work efficiency in human type 2 diabetes using 16-[18F]fluoro-4-thiapalmitate, a novel PET fatty acid tracer

Altered myocardial fuel selection likely underlies cardiac disease risk in diabetes, affecting oxygen demand and myocardial metabolic flexibility. We investigated myocardial fuel selection and metabolic flexibility in human type 2 diabetes mellitus (T2DM), using positron emission tomography to measure rates of myocardial fatty acid oxidation {16-[(18)F]fluoro-4-thia-palmitate (FTP)} and myocardial perfusion and total oxidation ([(11)C]acetate). Participants underwent paired studies under fasting conditions, comparing 3-h insulin + glucose euglycemic clamp conditions (120 mU·m(-2)·min(-1)) to 3-h saline infusion. Lean controls (n = 10) were compared with glycemically controlled volunteers with T2DM (n = 8). Insulin augmented heart rate, blood pressure, and stroke index in both groups (all P < 0.01) and significantly increased myocardial oxygen consumption (P = 0.04) and perfusion (P = 0.01) in both groups. Insulin suppressed available nonesterified fatty acids (P < 0.0001), but fatty acid concentrations were higher in T2DM under both conditions (P < 0.001). Insulin-induced suppression of fatty acid oxidation was seen in both groups (P < 0.0001). However, fatty acid oxidation rates were higher under both conditions in T2DM (P = 0.003). Myocardial work efficiency was lower in T2DM (P = 0.006) and decreased in both groups with the insulin-induced increase in work and shift in fuel utilization (P = 0.01). Augmented fatty acid oxidation is present under baseline and insulin-treated conditions in T2DM, with impaired insulin-induced shifts away from fatty acid oxidation. This is accompanied by reduced work efficiency, possibly due to greater oxygen consumption with fatty acid metabolism. These observations suggest that improved fatty acid suppression, or reductions in myocardial fatty acid uptake and retention, could be therapeutic targets to improve myocardial ischemia tolerance in T2DM.

Adipocytes enhance murine pancreatic cancer growth via a hepatocyte growth factor (HGF)-mediated mechanism

INTRODUCTION

Obesity accelerates the development and progression of pancreatic cancer, though the mechanisms underlying this association are unclear. Adipocytes are biologically active, producing factors such as hepatocyte growth factor (HGF) that may influence tumor progression. We therefore sought to test the hypothesis that adipocyte-secreted factors including HGF accelerate pancreatic cancer cell proliferation.

MATERIAL AND METHODS

Murine pancreatic cancer cells (Pan02 and TGP-47) were grown in a) conditioned medium (CM) from murine F442A preadipocytes, b) HGF-knockdown preadipocyte CM, c) recombinant murine HGF at increasing doses, and d) CM plus HGF-receptor (c-met) inhibitor. Cell proliferation was measured using the MTT assay. ANOVA and t-test were applied; p < 0.05 considered significant.

RESULTS

Wild-type preadipocyte CM accelerated Pan02 and TGP-47 cell proliferation relative to control (59 ± 12% and 34 ± 12%, p < 0.01, respectively). Knockdown of preadipocyte HGF resulted in attenuated proliferation vs. wild type CM in Pan02 cells (35 ± 5% vs. 68 ± 14% greater than control; p < 0.05), but proliferation in TGP-47 cells remained unchanged. Recombinant HGF dose-dependently increased Pan02, but not TGP-47, proliferation (p < 0.05). Inhibition of HGF receptor, c-met, resulted in attenuated proliferation versus control in Pan02 cells, but not TGP-47 cells.

CONCLUSIONS

These experiments demonstrate that adipocyte-derived factors accelerate murine pancreatic cancer proliferation. In the case of Pan02 cells, HGF is responsible, in part, for this proliferation.

Profound defects in β-cell function in screen-detected type 2 diabetes are not improved with glucose-lowering treatment in the Early Diabetes Intervention Program (EDIP)

BACKGROUND

Few studies have measured the ability of interventions to affect declining β-cell function in screen-detected type 2 diabetes. The Early Diabetes Intervention Programme (ClinicalTrials.gov NCT01470937) was a randomized study based on the hypothesis that improving postprandial glucose excursions with acarbose would slow the progression of fasting hyperglycaemia in screen-detected type 2 diabetes. In the Early Diabetes Intervention Programme, the effect of acarbose plus lifestyle advice on progression of fasting hyperglycaemia over a 5-year period was not greater than that of placebo. However, there was an early glucose-lowering effect of the trial. The objective of the current secondary analysis was to describe β-cell function changes in response to glucose lowering.

METHODS

Participants were overweight adult subjects with screen-detected type 2 diabetes. β-cell function was measured using hyperglycaemic clamps and oral glucose tolerance testing. The primary outcome was the change in β-cell function from baseline to year 1, the time point where the maximal glucose-lowering effect was seen.

RESULTS

At baseline, participants exhibited markedly impaired first-phase insulin response. Despite significant reductions in weight, fasting plasma glucose (PG) and 2-h PG, there was no clinically significant improvement in the first-phase insulin response. Late-phase insulin responses declined despite beneficial glycaemic effects of interventions.

CONCLUSIONS

Insulin secretion is already severely impaired in early, screen-detected type 2 diabetes. Effective glucose-lowering intervention with acarbose was not sufficient to improve insulin secretion or halt the decline of β-cell function.

The apéritif effect: Alcohol's effects on the brain's response to food aromas in women

OBJECTIVE

Consuming alcohol prior to a meal (an apéritif) increases food consumption. This greater food consumption may result from increased activity in brain regions that mediate reward and regulate feeding behavior. Using functional magnetic resonance imaging, we evaluated the blood oxygenation level dependent (BOLD) response to the food aromas of either roast beef or Italian meat sauce following pharmacokinetically controlled intravenous infusion of alcohol.

METHODS

BOLD activation to food aromas in non-obese women (n = 35) was evaluated once during intravenous infusion of 6% v/v EtOH, clamped at a steady-state breath alcohol concentration of 50 mg%, and once during infusion of saline using matching pump rates. Ad libitum intake of roast beef with noodles or Italian meat sauce with pasta following imaging was recorded.

RESULTS

BOLD activation to food relative to non-food odors in the hypothalamic area was increased during alcohol pre-load when compared to saline. Food consumption was significantly greater, and levels of ghrelin were reduced, following alcohol.

CONCLUSIONS

An alcohol pre-load increased food consumption and potentiated differences between food and non-food BOLD responses in the region of the hypothalamus. The hypothalamus may mediate the interplay of alcohol and responses to food cues, thus playing a role in the apéritif phenomenon.

Failure of hyperglycemia and hyperinsulinemia to compensate for impaired metabolic response to an oral glucose load

OBJECTIVE

To evaluate whether the augmented insulin and glucose response to a glucose challenge is sufficient to compensate for defects in glucose utilization in obesity and type 2 diabetes, using a breath test measurement of integrated glucose metabolism.

METHODS

Non-obese, obese normoglycemic and obese type 2 diabetic subjects were studied on 2 consecutive days. A 75g oral glucose load spiked with ¹³C-glucose was administered, measuring exhaled breath ¹³CO₂ as an integrated measure of glucose metabolism and oxidation. A hyperinsulinemic euglycemic clamp was performed, measuring whole body glucose disposal rate. Body composition was measured by DEXA. Multivariable analyses were performed to evaluate the determinants of the breath ¹³CO₂.

RESULTS

Breath ¹³CO₂ was reduced in obese and type 2 diabetic subjects despite hyperglycemia and hyperinsulinemia. The primary determinants of breath response were lean mass, fat mass, fasting FFA concentrations, and OGTT glucose excursion. Multiple approaches to analysis showed that hyperglycemia and hyperinsulinemia were not sufficient to compensate for the defect in glucose metabolism in obesity and diabetes.

CONCLUSIONS

Augmented insulin and glucose responses during an OGTT are not sufficient to overcome the underlying defects in glucose metabolism in obesity and diabetes.

Acute Changes in Sleep Duration on Eating Behaviors and Appetite-Regulating Hormones in Overweight/Obese Adults

There is considerable interest in the role of sleep in weight regulation, yet few studies have examined this relationship in overweight/obese (OW/OB) adults. Using a within-subject, counterbalanced design, 12 OW/OB women were studied in lab with two nights of short (5 hr time in bed [TIB]) and two nights of long (9 hr TIB) sleep. Hunger, consumption at a buffet, and fasting hormone levels were obtained. Significant polysomnographic differences occurred between conditions in total sleep time and sleep architecture (ps < .001). Percent energy from protein at the buffet increased following short sleep. No differences were observed for total energy intake or measured hormones. Further research is needed to determine how lengthening sleep impacts weight regulation in OW/OB adults.

Genetic and environmental influences on the prospective correlation between systemic inflammation and coronary heart disease death in male twins

OBJECTIVE

Because of lack of evidence, we aimed to examine to what degree low-grade systemic inflammation and coronary heart disease (CHD) death shared common genetic and environmental substrates.

APPROACH AND RESULTS

From the 41-year prospective National Heart, Lung, and Blood Institute Twin Study, we included 950 middle-aged male twins at baseline (1969-1973). Low-grade systemic inflammation was measured with plasma levels of interleukin-6 (IL-6) and C-reactive protein. Univariate and bivariate structural equation models were used, adjusted for a risk score for CHD death. The score-adjusted heritability was 19% for IL-6, 27% for C-reactive protein, and 22% for CHD death. The positive phenotypic correlation of IL-6 with CHD death (radjusted=0.27; 95% confidence interval [CI], 0.08-0.43) was driven by additive genetic factors (contribution [relative contribution], 0.30 [111%]) but attenuated by unique environment (-0.03 [-11%]). The genetic correlation between IL-6 and CHD death was 0.74 (95% CI, 0.21-1.00), whereas the unique environmental correlation was -0.05 (95% CI, -0.35 to 0.25). The proportion of genetic variance for CHD death shared with that for IL-6 was 74%. The phenotypic correlation of C-reactive protein with CHD death (radjusted=0.10; 95% CI, -0.02 to 0.22) was explained by additive genetic factors (0.20 [149%]) but was attenuated by the unique environment (-0.09 [-49%]). The genetic correlation of C-reactive protein with CHD death was 0.63 (95% CI, -0.07 to 1.00), whereas the unique environmental correlation was -0.07 (95% CI, -0.29 to 0.17).

CONCLUSIONS

Low-grade systemic inflammation, measured by IL-6, and long-term CHD death share moderate genetic substrates that augment both traits.

Ventral frontal satiation-mediated responses to food aromas in obese and normal-weight women

BACKGROUND

Sensory properties of foods promote and guide consumption in hunger states, whereas satiation should dampen the sensory activation of ingestive behaviors. Such activation may be disordered in obese individuals.

OBJECTIVE

Using functional magnetic resonance imaging (fMRI), we studied regional brain responses to food odor stimulation in the sated state in obese and normal-weight individuals targeting ventral frontal regions known to be involved in coding for stimulus reward value.

DESIGN

Forty-eight women (25 normal weight; 23 obese) participated in a 2-day (fed compared with fasting) fMRI study while smelling odors of 2 foods and an inedible, nonfood object. Analyses were conducted to permit an examination of both general and sensory-specific satiation (satiation effects specific to a given food).

RESULTS

Normal-weight subjects showed significant blood oxygen level-dependent responses in the ventromedial prefrontal cortex (vmPFC) to food aromas compared with responses induced by the odor of an inedible object. Normal-weight subjects also showed general (but not sensory-specific) satiation effects in both the vmPFC and orbitofrontal cortex. Obese subjects showed no differential response to the aromas of food and the inedible object when fasting. Within- and between-group differences in satiation were driven largely by changes in the response to the odor of the inedible stimulus. Responses to food aromas in the obese correlated with trait negative urgency, the tendency toward negative affect-provoked impulsivity.

CONCLUSIONS

Ventral frontal signaling of reward value may be disordered in obesity, with negative urgency heightening responses to food aromas. The observed nature of responses to food and nonfood stimuli suggests that future research should independently quantify each to fully understand brain reward signaling in obesity.

[13C]glucose breath testing provides a noninvasive measure of insulin resistance: calibration analyses against clamp studies

BACKGROUND

Exhaled (13)CO2 following ingestion of [(13)C]glucose with a standard oral glucose tolerance load correlates with blood glucose values but is determined by tissue glucose uptake. Therefore exhaled (13)CO2 may also be a surrogate measure of the whole-body glucose disposal rate (GDR) measured by the gold standard hyperinsulinemic euglycemic clamp.

SUBJECTS AND METHODS

Subjects from across the glycemia range were studied on 2 consecutive days under fasting conditions. On Day 1, a 75-g oral glucose load spiked with [(13)C]glucose was administered. On Day 2, a hyperinsulinemic euglycemic clamp was performed. Correlations between breath parameters and clamp-derived GDR were evaluated, and calibration analyses were performed to evaluate the precision of breath parameter predictions of clamp measures.

RESULTS

Correlations of breath parameters with GDR and GDR per kilogram of fat-free mass (GDRffm) ranged from 0.54 to 0.61 and 0.54 to 0.66, respectively (all P<0.001). In calibration analyses the root mean square error for breath parameters predicting GDR and GDRffm ranged from 2.32 to 2.46 and from 3.23 to 3.51, respectively. Cross-validation prediction error (CVPE) estimates were 2.35-2.51 (GDR) and 3.29-3.57 (GDRffm). Prediction precision of breath enrichment at 180 min predicting GDR (CVPE=2.35) was superior to that for inverse insulin (2.68) and the Matsuda Index (2.51) but inferior to that for the log of homeostasis model assessment (2.21) and Quantitative Insulin Sensitivity Check Index (2.29) (all P<10(-5)). Similar patterns were seen for predictions of GDRffm.

CONCLUSIONS

(13)CO2 appearance in exhaled breath following a standard oral glucose load with added [(13)C]glucose provides a valid surrogate index of clamp-derived measures of whole-body insulin resistance, with good accuracy and precision. This noninvasive breath test-based approach can provide a useful measure of whole-body insulin resistance in physiologic and epidemiologic studies.

Oncostatin m is produced in adipose tissue and is regulated in conditions of obesity and type 2 diabetes

CONTEXT

Adipose tissue is a highly active endocrine organ that secretes many factors that affect other tissues and whole-body metabolism. Adipocytes are responsive to several glycoprotein 130 (gp130) cytokines, some of which have been targeted as potential antiobesity therapeutics.

OBJECTIVE

Oncostatin M (OSM) is a gp130 family member known to inhibit adipocyte differentiation in vitro, but its effects on other adipocyte properties are not characterized. The expression of OSM in white adipose tissue (WAT) has not been evaluated in the context of obesity. Thus, our objective was to examine the expression of adipose tissue OSM in obese animals and humans.

DESIGN

OSM expression was examined in adipose tissues from mice with diet-induced and genetic obesity and in obese humans as well as in fractionated adipose tissue from mice. Murine adipocytes were used to examine OSM receptor expression and the effects of OSM on adipocytes, including the secretion of factors such as plasminogen activator inhibitor 1 and IL-6, which are implicated in metabolic diseases.

RESULTS

OSM expression is increased in rodent and human obesity/type 2 diabetes mellitus. In humans, OSM levels correlate with body weight and insulin and are inversely correlated with glucose disposal rate as measured by hyperinsulinemic-euglycemic clamp. OSM is not produced from the adipocytes in WAT but derives from cells in the stromovascular fraction, including F4/80(+) macrophages. The specific receptor of OSM, OSM receptor-β, is expressed in adipocytes and adipose tissue and increased in both rodent models of obesity examined. OSM acts on adipocytes to induce the expression and secretion of plasminogen activator inhibitor 1 and IL-6.

CONCLUSIONS

These data indicate that WAT macrophages are a source of OSM and that OSM levels are significantly induced in murine and human obesity/type 2 diabetes mellitus. These studies suggest that OSM produced from immune cells in WAT acts in a paracrine manner on adipocytes to promote a proinflammatory phenotype in adipose tissue.

Hepatocyte growth factor regulates neovascularization in developing fat pads

In this study, we used lentiviral-delivered shRNA to generate a clonal line of 3T3-F442A preadipocytes with stable silencing of hepatocyte growth factor (HGF) expression and examined the long-term consequence of this modification on fat pad development. HGF mRNA expression was reduced 94%, and HGF secretion 79% (P < 0.01), compared with preadipocytes treated with nontargeting shRNA. Fat pads derived from HGF knockdown preadipocytes were significantly smaller (P < 0.01) than control pads beginning at 3 days postinjection (0.022 ± 0.003 vs. 0.037 ± 0.004 g), and further decreased in size at day 7 (0.015 ± 0.004 vs. 0.037 ± 0.003 g) and day 14 (0.008 ± 0.002 vs. 0.045 ± 0.007 g). Expression of the endothelial cell genes TIE1 and PECAM1 increased over time in control fat pads (1.6 ± 0.4 vs. 11.4 ± 1.7 relative units at day 3 and 14, respectively; P < 0.05) but not in HGF knockdown fat pads (1.1 ± 0.5 vs. 5.9 ± 2.2 relative units at day 3 and 14). Contiguous vascular structures were observed in control fat pads but were much less developed in HGF knockdown fat pads. Differentiation of preadipocytes to mature adipocytes was significantly attenuated in HGF knockdown fat pads. Fat pads derived from preadipocytes with knockdown of the HGF receptor c-MET were smaller than control pads at day 3 postinjection (0.034 ± 0.002 vs. 0.049 ± 0.004 g; P < 0.05), and remained the same size through day 14. c-MET knockdown fat pads developed a robust vasculature, and preadipocytes differentiated to mature adipocytes. Overall these data suggest that preadipocyte-secreted HGF is an important regulator of neovascularization in developing fat pads.

Changes in children's sleep duration on food intake, weight, and leptin

OBJECTIVE

To examine the effect of experimental changes in children's sleep duration on self-reported food intake, food reinforcement, appetite-regulating hormones, and measured weight.

METHODS

Using a within-subjects, counterbalanced, crossover design, 37 children, 8 to 11 years of age (27% overweight/obese) completed a 3-week study. Children slept their typical amount at home for 1 week and were then randomized to either increase or decrease their time in bed by 1.5 hours per night for 1 week, completing the alternate schedule on the third week. Primary outcomes were dietary intake as assessed by 24-hour dietary recalls, food reinforcement (ie, points earned for a food reward), and fasting leptin and ghrelin. The secondary outcome was child weight.

RESULTS

Participants achieved a 2 hour, 21 minute difference in the actigraph defined sleep period time between the increase and decrease sleep conditions (P < .001). Compared with the decrease sleep condition, during the increase condition, children reported consuming an average of 134 kcal/day less (P < .05), and exhibited lower fasting morning leptin values (P < .05). Measured weights were 0.22 kg lower during the increase sleep than the decrease sleep condition (P < .001). There were no differences in food reinforcement or in fasting ghrelin.

CONCLUSIONS

Compared with decreased sleep, increased sleep duration in school-age children resulted in lower reported food intake, lower fasting leptin levels, and lower weight. The potential role of sleep duration in pediatric obesity prevention and treatment warrants further study.

Adaptive changes of the Insig1/SREBP1/SCD1 set point help adipose tissue to cope with increased storage demands of obesity

The epidemic of obesity imposes unprecedented challenges on human adipose tissue (WAT) storage capacity that may benefit from adaptive mechanisms to maintain adipocyte functionality. Here, we demonstrate that changes in the regulatory feedback set point control of Insig1/SREBP1 represent an adaptive response that preserves WAT lipid homeostasis in obese and insulin-resistant states. In our experiments, we show that Insig1 mRNA expression decreases in WAT from mice with obesity-associated insulin resistance and from morbidly obese humans and in in vitro models of adipocyte insulin resistance. Insig1 downregulation is part of an adaptive response that promotes the maintenance of SREBP1 maturation and facilitates lipogenesis and availability of appropriate levels of fatty acid unsaturation, partially compensating the antilipogenic effect associated with insulin resistance. We describe for the first time the existence of this adaptive mechanism in WAT, which involves Insig1/SREBP1 and preserves the degree of lipid unsaturation under conditions of obesity-induced insulin resistance. These adaptive mechanisms contribute to maintain lipid desaturation through preferential SCD1 regulation and facilitate fat storage in WAT, despite on-going metabolic stress.

Effect of acarbose to delay progression of carotid intima-media thickness in early diabetes

BACKGROUND

The anti-diabetic agent acarbose reduces postprandial glucose excursions. We have evaluated the effect of randomized treatment with acarbose on the progression of carotid intima-media thickness (IMT) in early diabetes.

METHODS

The Early Diabetes Intervention Program was a randomized trial of acarbose versus placebo in 219 participants with early diabetes characterized by glucose values over 11.1 mmol/L 2 h after a 75 g oral glucose load and a mean HbA1c of 6.3%. IMT was measured at baseline and yearly. Follow-up was discontinued if participants progressed to the study glucose endpoints; IMT readings were available for a median of 2 years, with 72 subjects followed for 5 years.

RESULTS

Progressive increases in IMT were seen in both treatment groups, but progression was reduced in participants randomized to acarbose (p = 0.047). In age, sex and smoking-adjusted analyses, IMT progression was associated with greater fasting and oral glucose tolerance test-excursion glucose, fasting insulin, cholesterol and glycated low-density lipoprotein concentrations. IMT progression was reduced with study-related changes in weight, insulin and non-esterified fatty acids; these features were more strongly associated with reduced IMT progression than acarbose treatment. Despite strong associations of baseline glycemia with IMT progression, study-related changes in glucose were not important determinants of IMT progression.

CONCLUSIONS

Acarbose can delay progression of carotid intima-media thickness in early diabetes defined by an oral glucose tolerance test. Glucose, weight, insulin and lipids contributed to risk of progression but reductions in glycemia were not major determinants of reduced rate of IMT progression. Vascular benefits of acarbose may be independent of its glycemic effects.

Impaired cardiometabolic responses to glucagon-like peptide 1 in obesity and type 2 diabetes mellitus

Glucagon-like peptide 1 (GLP-1) has insulin-like effects on myocardial glucose uptake which may contribute to its beneficial effects in the setting of myocardial ischemia. Whether these effects are different in the setting of obesity or type 2 diabetes (T2DM) requires investigation. We examined the cardiometabolic actions of GLP-1 (7-36) in lean and obese/T2DM humans, and in lean and obese Ossabaw swine. GLP-1 significantly augmented myocardial glucose uptake under resting conditions in lean humans, but this effect was impaired in T2DM. This observation was confirmed and extended in swine, where GLP-1 effects to augment myocardial glucose uptake during exercise were seen in lean but not in obese swine. GLP-1 did not increase myocardial oxygen consumption or blood flow in humans or in swine. Impaired myocardial responsiveness to GLP-1 in obesity was not associated with any apparent alterations in myocardial or coronary GLP1-R expression. No evidence for GLP-1-mediated activation of cAMP/PKA or AMPK signaling in lean or obese hearts was observed. GLP-1 treatment augmented p38-MAPK activity in lean, but not obese cardiac tissue. Taken together, these data provide novel evidence indicating that the cardiometabolic effects of GLP-1 are attenuated in obesity and T2DM, via mechanisms that may involve impaired p38-MAPK signaling.

Insulin infusion reduces hepatocyte growth factor in lean humans

OBJECTIVE

Plasma Hepatocyte Growth Factor (HGF) is significantly elevated in obesity and may contribute to vascular disease, metabolic syndrome or cancer in obese individuals. The current studies were done to determine if hyperinsulinemia increases plasma HGF.

MATERIALS/METHODS

Twenty-two participants (10 women/12 men, BMI 20.6-34.5 kg/m(2), age 18-49 years) underwent a hyperinsulinemic euglycemic clamp with measurement of HGF at baseline and steady state. Relationships between baseline HGF, anthropometrics, triglycerides, liver enzymes, c-reactive protein and adiponectin were also evaluated.

RESULTS

Fasting HGF was positively correlated (P<0.050) with weight (r=0.63), BMI (r=0.55), waist circumference (r=0.68), WHR (r=0.48), triglycerides (r=0.44), alanine aminotransferase (r=0.74) and γ-glutamyl transpeptidase (r=0.56), but not c-reactive protein or adiponectin. In stepwise regression, alanine aminotransferase and insulin sensitivity accounted for significant variation in fasting HGF. A significant effect of insulin to suppress HGF during the clamp (P=0.029) was found after adjustment for BMI. HGF was reduced 7% at steady state in the lean subjects only (437.1 ±57.8 vs 405.4±72.0 pg/ml; P=0.030).

CONCLUSIONS

The positive correlation of HGF with hepatic enzymes suggests liver may be a significant source of circulating HGF in lean subjects. The strong correlation of plasma HGF with adiposity and the lack of an effect of insulin to increase HGF during the clamp in obese subjects suggest that adiposity, rather than elevated insulin levels, may be the major contributor to plasma HGF in obese subjects. Thus, a reduction in plasma HGF through weight loss is likely the best way to decrease comorbidities mediated by this angiogenic and mitogenic factor.

The angiogenic inhibitor TNP-470 decreases caloric intake and weight gain in high-fat fed mice

The angiogenic inhibitor TNP-470 attenuates high-fat diet-induced obesity; however, it is not clear how the compound alters energy balance to prevent weight gain. Five-week-old C57BL/6J mice were fed high-fat diet (45% energy from fat) for 6.5 weeks and treated with TNP-470 (20 mg/kg body weight; n = 7) or vehicle (saline; n = 7). Control mice (n = 8) received standard chow and sham injection. TNP-470 mice initially gained weight, but by day 5 body weight was significantly less than high-fat fed (HFF) mice and not different from that of chow-fed mice, an effect maintained to the end of the study (28.6 ± 0.6 vs. 22.4 ± 0.6 and 22.2 ± 0.5 g). Percent body fat was reduced in TNP-470 compared to HFF mice, but was greater than that of chow mice (34.0 ± 1.5, 23.9 ± 1.5, and 17.0 ± 1.4%, P < 0.05). Food intake in TNP-470-treated mice was less (P < 0.05) than that in HFF mice by day 5 of treatment (2.5 ± 0.1 vs. 2.8 ± 0.1 g/mouse/day) and remained so to the end of the study. Twenty-four hours energy expenditure was greater (P < 0.05) in TNP-470 than HFF or chow mice (7.05 ± 0.07 vs. 6.69 ± 0.08 vs. 6.79 ± 0.09 kcal/kg/h), an effect not explained by a difference in energy expended in locomotion. Despite normalization of body weight, TNP-470 mice exhibited impaired glucose tolerance (area under the curve 30,556 ± 1,918 and 29,290 ± 1,584 vs. 24,421 ± 903 for TNP, HFF, and chow fed, P < 0.05). In summary, the angiogenic inhibitor TNP-470 attenuates weight gain in HFF mice via a reduction in caloric intake and an increase in energy expenditure.

Insulin and Endothelin in the Acute Regulation of Adiponectin in Vivo in Humans

OBJECTIVE

In vitro, insulin and endothelin (ET) both modulate adiponectin secretion from adipocyte cell lines. The current studies were performed to assess whether endogenous ET contributes to the acute action of insulin infusions on adiponectin levels in vivo in humans.

RESEARCH METHODS AND PROCEDURES

We studied 17 lean and 20 obese subjects (BMI 21.8 +/- 2.2 and 34.0 +/- 5.0 kg/m(2), respectively). Hyperinsulinemic euglycemic clamp studies were performed using insulin infusion rates of 10, 30, or 300 mU/m(2) per minute alone or with concurrent infusion of BQ123, an antagonist of type A ET receptors. Circulating adiponectin levels were assessed at baseline and after achievement of steady-state glucose with the insulin infusion.

RESULTS

Adiponectin levels were lower in obese than lean subjects (6.76 +/- 3.66 vs. 8.37 +/- 2.79 microg/mL, p = 0.0148 adjusted for differences across gender). Insulin infusions suppressed adiponectin by a mean of 7.8% (p < 0.0001). In a subset of 13 lean and 14 obese subjects for whom data with and without BQ123 were available, there was no evident effect of BQ123 to modulate clamp-associated suppression of adiponectin (p = 0.16). Surprisingly, there was no evident relationship between steady-state insulin concentrations and adiponectin suppression (r = 0.14, p = 0.30), and again no effect of BQ123 to modify this relationship was seen.

DISCUSSION

Despite baseline differences in adiponectin levels, we observed equal suppression of adiponectin with insulin infusions in lean and obese subjects. ET receptor antagonism with BQ123 did not modulate this effect, suggesting that endogenous ET does not have a role in modifying the acute effects of insulin on adiponectin production and/or disposition.

Lower Serum Adiponectin Levels in African-American Boys

OBJECTIVE

To examine adiponectin, an adipocyte-secreted hormone with anti-inflammatory and insulin-sensitizing effects, in relation to race or gender in younger subjects.

RESEARCH METHODS AND PROCEDURES

The relationship of adiponectin, quantitated by radioimmunoassay, to anthropometric and metabolic factors (fasting insulin, glucose, and leptin) and reproductive hormones was examined in 46 healthy African Americans (25 girls/21 boys) and 40 whites (20 girls/20 boys) ranging in age from 12 to 21 years.

RESULTS

There was no statistical difference in BMI or in BMI percentile among the four groups. Sums of skinfolds, but not skinfold percentile, were significantly lower in boys than girls (p = 0.001 and p = 0.896, respectively), whereas there was no difference between racial groups. Leptin was significantly greater in girls (p = 0.0002). There was no difference in fasting serum glucose, insulin, or homeostasis model assessment score among any of the groups. There was a significant negative univariate relationship between serum adiponectin and both BMI and BMI percentile for the entire group (p = 0.006 and p = 0.005). In a multivariate model, BMI percentile (p = 0.005) and the interaction between race and gender (p = 0.026) were significant predictors of serum adiponectin. In this model, African-American boys had the lowest serum adiponectin level, 37% less than white boys, who had the highest adiponectin levels.

DISCUSSION

Serum adiponectin levels are reduced in young obese subjects (African Americans and whites) and are lower in African-American boys than white boys. A lower adiponectin level in African-American boys may predispose this group to a greater risk of diabetes and cardiovascular disease.

Serum leptin, parathyroid hormone, 1,25-dihydroxyvitamin D, fibroblast growth factor 23, bone alkaline phosphatase, and sclerostin relationships in obesity

BACKGROUND

Obesity is associated with hyperparathyroidism and increased bone mass and turnover, but their pathogeneses are unclear.

AIMS

Our aim was to determine in obesity interrelationships among serum levels of leptin, the mineral-regulating hormones, bone turnover markers, and sclerostin.

METHODS

This case-control study was performed in 20 women having bariatric surgery and 20 control women matched for race and age. Anthropometrics and fasting serum biochemistries were measured in controls and in bariatric patients the morning of surgery.

RESULTS

Body mass index (48.9 vs. 25.4 kg/m(2)), weight (128.6 vs. 71.9 kg), serum leptin (74.6 vs. 25.2 ng/ml), PTH (44.5 vs. 28.8 pg/ml), fibroblast growth factor 23 (FGF23) (42.4 vs. 25.9 pg/ml), and bone alkaline phosphatase (BAP) (25.8 vs. 17.5 U/liter) were higher, but height (162.3 vs. 167.7 cm) and 1,25-dihydroxyvitamin D (1,25D) (39.2 vs. 48.7 pg/ml) were lower in bariatric surgery patients than controls. There was no difference in serum sclerostin, amino-terminal collagen cross-links, 25-hydroxyvitamin D (25D), calcium, phosphate, and creatinine between groups. In the combined sample, leptin was positively related to PTH, FGF23, and BAP but not to 1,25D or sclerostin. Multiple regression analysis demonstrated that PTH was predicted by leptin and Ca (R(2) = 0.39); 1,25D by 25D, FGF23, and phosphate (R(2) = 0.43); FGF23 by leptin and 1,25D (R(2) = 0.27); BAP by leptin, PTH, and Ca (R(2) = 0.39); and sclerostin by leptin and PTH (R(2) = 0.20).

CONCLUSIONS

Women having bariatric surgery had higher leptin, PTH, FGF23, and BAP and lower 1,25D than controls. Leptin predicted the serum levels of PTH, 1,25D, and FGF23, the mineral-regulating hormones, and BAP, a bone formation marker, in women with body mass index ranging from 13.9-65.8 kg/m(2). The results suggest that leptin has an endocrine or paracrine effect on PTH and FGF23 production and that PTH may be one of the signals in obesity that leads to increased bone mass.