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The treatment of diabetes can be complex and overwhelming for patients as it demands persistent attention to lifestyle management, adherence to medications, monitoring of side effects of drugs, and management of devices for glucose monitoring and/or insulin infusion. Therefore, understanding patient-reported outcomes (PROs) that provide direct insight into the patient's experience with diabetes is crucial for optimizing diabetes management.This review provides an overview of commonly used PRO questionnaires that assess different aspects of diabetes management.

Insulin signalling in the central nervous system regulates energy homeostasis by controlling metabolism in several organs and by coordinating organ crosstalk. Studies performed in rodents, non-human primates and humans over more than five decades using intracerebroventricular, direct hypothalamic or intranasal application of insulin provide evidence that brain insulin action might reduce food intake and, more importantly, regulates energy homeostasis by orchestrating nutrient partitioning. This Review discusses the metabolic pathways that are under the control of brain insulin action and explains how brain insulin resistance contributes to metabolic disease in obesity, the metabolic syndrome and type 2 diabetes mellitus. This Review critically evaluates the studies that support and refute the role of brain insulin in systemic nutrient partitioning. The authors discuss the role of brain insulin in metabolic control and the contribution of brain insulin resistance to metabolic disease and assess the therapeutic potential of enhancing or restoring brain insulin signalling in metabolic disease.

CONTEXT: Although glucocorticoids (GCs) have potent anti-inflammatory actions, patients with hypercortisolism due to Cushing disease (CD) have increased circulating proinflammatory cytokines that may contribute to their insulin resistance and cardiovascular disease. The mechanisms and tissues that account for the increased systemic inflammation in patients with CD are unknown. OBJECTIVE: To determine whether chronic endogenous GC exposure due to CD is associated with adipose tissue (AT) inflammation in humans. DESIGN, SETTING, PARTICIPANTS: Abdominal subcutaneous AT samples from 10 patients with active CD and 10 age-, sex-, and body mass index‒matched healthy subjects were assessed for macrophage infiltration and mRNA expression of proinflammatory cytokines. MAIN OUTCOME MEASURE: Using immunohistochemistry, AT samples were analyzed for the expression of vimentin, caspase, CD3, CD4, CD8, CD11c, CD20, CD31, CD56, CD68, and CD163. Quantitative PCR was used to assess the mRNA gene expression of arginase, CD11b, CD68, EMR-1, IL-6, IL-10, MCP-1, and TNF-α. RESULTS: Immunohistochemistry revealed higher mean percentage infiltration of CD68(+) macrophages and CD4(+) T lymphocytes, increased mean area of CD11c(+) M1 macrophages, higher number of CD11c(+) crownlike structures, and decreased vimentin in the AT of patients with active CD compared with controls. PCR revealed no differences in mRNA expression of any analyzed markers in patients with CD. CONCLUSIONS: Chronic exposure to GCs due to CD increases the presence of AT macrophages, a hallmark of AT inflammation. Hence, AT inflammation may be the source of the systemic inflammation seen in CD, which in turn may contribute to obesity, insulin resistance, and cardiovascular disease in these patients.

Both obesity and aging increase susceptibility to metabolic disease and type 2 diabetes where adipose tissue dysfunction is a hallmark. In both conditions, impaired autonomic control is believed to play a key role in disrupted CNS control of metabolism. However, the role of the sympathetic nervous system (SNS) and catecholaminergic signaling in metabolic disease has not been well defined in large part due to a lack of suitable animal models(1). Surgical denervation is not specific to the SNS and chemical sympathectomy through 6-hydroxydopamine causes inflammation due to toxic effects. Abrogation of catecholamine (CA) synthesis in the whole body due to genetic deletion of the gene for tyrosine hydroxylase (th), a key enzyme in CA synthesis, results in embryonic lethality likely due to the lack of dopamine and norepinephrine in the CNS where they serve as key neurotransmitters. Here we studied the role of the SNS and catecholaminergic signaling in metabolic control in both aging as well as high fat diet (HFD) induced obesity. We created a mouse model of inducible th gene deletion that is restricted to the periphery, including sympathetic fibers of the peripheral NS but spares the brain as a pharmaco-genetic model of sympathectomy(2). TH is deleted and CA levels were reduced more than 90% in peripheral tissues of TH KO mice, while intact in the CNS. TH KO mice are cold intolerant consistent with functional sympathectomy. Interestingly, TH KO mice are protected from HFD feeding induced glucose intolerance (AUC during GTT: WT1018.8±42.0 mg/dl/hr vs. TH KO 485.0±85.8 mg/dl/hr; p < 0.0001; n = 6) even though food intake increased in TH KO mice. In 20 months old TH KO mice glucose tolerance was improved and fasting blood glucose levels were reduced (AUC during GTT: WT 357.3±16.2 mg/dl/hr vs. TH KO 254.5±15.6 mg/dl/hr; p < 0.01; n = 12) with higher insulin levels (WT 0.35±0.07 μg/l vs. TH KO 1.28±0.28 μg/l; p < 0.001; n = 9). Of note, insulin tolerance tests did not show marked differences. Both obesity and aging are characterized by impaired adipose tissue function with reduced lipogenic capacity. TH KO mice fed a HFD exhibit increased WAT de novo lipogenesis, lower lipolysis, and trend to exhibit decreased adipose tissue inflammation, suggesting that the SNS is a major culprit for the impaired lipogenic capacity in adipose tissue. Our data provides support for the paradigm that impaired SNS function plays an important role in the dysmetabolic states of obesity and aging. Reference 1. Ryu V, Buettner C. Fat cells gobbling up norepinephrine? PLoS Biol. 2019;17(2):e3000138. 2. Fischer K, Ruiz HH, Jhun K, Finan B, Oberlin DJ, van der Heide V, et al. Alternatively activated macrophages do not synthesize catecholamines or contribute to adipose tissue adaptive thermogenesis. Nature medicine. 2017;23(5):623-30.

Background Type 2 diabetes (T2D) is a recognized risk factor for the development of cognitive impairment (CI) and/or dementia, although the exact nature of the molecular pathology of T2D-associated CI remains obscure. One link between T2D and CI might involve decreased insulin signaling in brain and/or neurons in either animal or postmortem human brains as has been reported as a feature of Alzheimer’s disease (AD). Here we asked if neuronal insulin resistance is a cell autonomous phenomenon in a familial form of AD. Methods We have applied a newly developed protocol for deriving human basal forebrain cholinergic neurons (BFCN) from skin fibroblasts via induced pluripotent stem cell (iPSC) technology. We generated wildtype and familial AD mutant PSEN2N141I (presenilin 2) BFCNs and assessed if insulin signaling, insulin regulation of the major AD proteins Aβ and/or tau, and/or calcium fluxes is altered by the PSEN2N141I mutation. Results We report herein that wildtype, PSEN2N141I and CRISPR/Cas9-corrected iPSC-derived BFCNs (and their precursors) show indistinguishable insulin signaling profiles as determined by the phosphorylation of canonical insulin signaling pathway molecules. Chronic insulin treatment of BFCNs of all genotypes led to a reduction in the Aβ42/40 ratio. Unexpectedly, we found a CRISPR/Cas9-correctable effect of PSEN2N141I on calcium flux, which could be prevented by chronic exposure of BFCNs to insulin. Conclusions Our studies indicate that the familial AD mutation PSEN2N141I does not induce neuronal insulin resistance in a cell autonomous fashion. The ability of insulin to correct calcium fluxes and to lower Aβ42/40 ratio suggests that insulin acts to oppose an AD-pathophysiology. Hence, our results are consistent with a potential physiological role for insulin as a mediator of resilience by counteracting specific metabolic and molecular features of AD. Electronic supplementary material The online version of this article (10.1186/s13024-018-0265-5) contains supplementary material, which is available to authorized users.

Considerable overlap has been identified in the risk factors, comorbidities and putative pathophysiological mechanisms of Alzheimer disease and related dementias (ADRDs) and type 2 diabetes mellitus (T2DM), two of the most pressing epidemics of our time. Much is known about the biology of each condition, but whether T2DM and ADRDs are parallel phenomena arising from coincidental roots in ageing or synergistic diseases linked by vicious pathophysiological cycles remains unclear. Insulin resistance is a core feature of T2DM and is emerging as a potentially important feature of ADRDs. Here, we review key observations and experimental data on insulin signalling in the brain, highlighting its actions in neurons and glia. In addition, we define the concept of ‘brain insulin resistance’ and review the growing, although still inconsistent, literature concerning cognitive impairment and neuropathological abnormalities in T2DM, obesity and insulin resistance. Lastly, we review evidence of intrinsic brain insulin resistance in ADRDs. By expanding our understanding of the overlapping mechanisms of these conditions, we hope to accelerate the rational development of preventive, disease-modifying and symptomatic treatments for cognitive dysfunction in T2DM and ADRDs alike.

Objective The transcription factor Kruppel-like factor 14 (KLF14) has been associated with type 2 diabetes and high-density lipoprotein-cholesterol (HDL-C) through genome-wide association studies. The mechanistic underpinnings of KLF14's control of metabolic processes remain largely unknown. We studied the physiological roles of KLF14 in a knockout (KO) mouse model. Methods Male whole body Klf14 KO mice were fed a chow or high fat diet (HFD) and diet induced phenotypes were analyzed. Additionally, tissue-specific expression of Klf14 was determined using RT-PCR, RNA sequencing, immunoblotting and whole mount lacZ staining. Finally, the consequences of KLF14 loss-of-function were studied using RNA sequencing in tissues with relatively high Klf14 expression levels. Results KLF14 loss-of-function did not affect HFD-induced weight gain or insulin resistance. Fasting plasma concentrations of glucose, insulin, cholesterol, HDL-C and ApoA-I were also comparable between Klf14 +/+ and Klf14 −/− mice on chow and HFD. We found that in mice expression of Klf14 was the highest in the anterior pituitary (adenohypophysis), lower but detectable in white adipose tissue and undetectable in liver. Loss of KLF14 function impacted on the pituitary transcriptome with extracellular matrix organization as the primary affected pathway and a predicted link to glucocorticoid receptor signaling. Conclusions Whole body loss of KLF14 function in male mice does not result in metabolic abnormalities as assessed under chow and HFD conditions. Mostly likely there is redundancy for the role of KLF14 in the mouse and a diverging function in humans.

Germline ablation of VGF, a secreted neuronal, neuroendocrine, and endocrine peptide precursor, results in lean, hypermetabolic, and infertile adult mice that are resistant to diet-, lesion-, and genetically-induced obesity and diabetes (Hahm et al., 1999, 2002). To assess whether this phenotype is predominantly driven by reduced VGF expression in developing and/or adult neurons, or in peripheral endocrine and neuroendocrine tissues, we generated and analyzed conditional VGF knockout mice, obtained by mating loxP-flanked (floxed) Vgf mice with either pan-neuronal Synapsin-Cre- or forebrain alpha-CaMKII-Cre-recombinase-expressing transgenic mice. Adult male and female mice, with conditional ablation of the Vgf gene in embryonic neurons had significantly reduced body weight, increased energy expenditure, and were resistant to diet-induced obesity. Conditional forebrain postnatal ablation of VGF in male mice, primarily in adult excitatory neurons, had no measurable effect on body weight nor on energy expenditure, but led to a modest increase in adiposity, partially overlapping the effect of AAV-Cre-mediated targeted ablation of VGF in the adult ventromedial hypothalamus and arcuate nucleus of floxed Vgf mice (Foglesong et al., 2016), and also consistent with results of icv delivery of the VGF-derived peptide TLQP-21 to adult mice, which resulted in increased energy expenditure and reduced adiposity (Bartolomucci et al., 2006). Because the lean, hypermetabolic phenotype of germline VGF knockout mice is to a great extent recapitulated in Syn-Cre+/−,Vgfflpflox/flpflox mice, we conclude that the metabolic profile of germline VGF knockout mice is largely the result of VGF ablation in embryonic CNS neurons, rather than peripheral endocrine and/or neuroendocrine cells, and that in forebrain structures such as hypothalamus, VGF and/or VGF-derived peptides play uniquely different roles in the developing and adult nervous system.

Insulin is a key regulator of adipose tissue lipolysis, and impaired adipose tissue insulin action results in unrestrained lipolysis and lipotoxicity, which are hallmarks of the metabolic syndrome and diabetes. Insulin regulates adipose tissue metabolism through direct effects on adipocytes and through signaling in the central nervous system by dampening sympathetic outflow to the adipose tissue. Here we examined the role of insulin signaling in agouti-related protein (AgRP) and pro-opiomelanocortin (POMC) neurons in regulating hepatic and adipose tissue insulin action. Mice lacking the insulin receptor in AgRP neurons (AgRP IR KO) exhibited impaired hepatic insulin action because the ability of insulin to suppress hepatic glucose production (hGP) was reduced, but the ability of insulin to suppress lipolysis was unaltered. To the contrary, in POMC IR KO mice, insulin lowered hGP but failed to suppress adipose tissue lipolysis. High-fat diet equally worsened glucose tolerance in AgRP and POMC IR KO mice and their respective controls but increased hepatic triglyceride levels only in POMC IR KO mice, consistent with impaired lipolytic regulation resulting in fatty liver. These data suggest that although insulin signaling in AgRP neurons is important in regulating glucose metabolism, insulin signaling in POMC neurons controls adipose tissue lipolysis and prevents high-fat diet–induced hepatic steatosis.

Insulin replacement is the cornerstone of type 1 diabetes (T1D) treatment; however, glycemic control remains a challenge. Leptin has been shown to effectively restore euglycemia in rodent models of T1D; however, the mechanism or mechanisms by which leptin exerts glycemic control are unclear. In this issue of the JCI, Perry and colleagues provide evidence that suppression of lipolysis is a key facet of leptin-mediated restoration of euglycemia. However, more work remains to be done to fully understand the antidiabetic mechanisms of leptin.

This study suggests that agents able to enhance the activity of β-arrestin-1 in AgRP neurons may be useful as antidiabetic drugs., β-Arrestin-1 and β-arrestin-2 have emerged as important signaling molecules that modulate glucose fluxes in several peripheral tissues. The potential roles of neuronally expressed β-arrestins in regulating glucose homeostasis remain unknown. We here report that mice lacking β-arrestin-1 (barr1) selectively in AgRP neurons displayed impaired glucose tolerance and insulin sensitivity when consuming an obesogenic diet, while mice overexpressing barr1 selectively in AgRP neurons were protected against obesity-associated metabolic impairments. Additional physiological, biochemical, and electrophysiological data indicated that the presence of barr1 is essential for insulin-mediated hyperpolarization of AgRP neurons. As a result, barr1 expressed by AgRP neurons regulates efferent neuronal pathways that suppress hepatic glucose production and promote lipolysis in adipose tissue. Mice lacking β-arrestin-2 (barr2) selectively in AgRP neurons showed no substantial metabolic phenotypes. Our data suggest that agents able to enhance the activity of barr1 in AgRP neurons may prove beneficial as antidiabetic drugs.

Background: Dichlorodiphenyltrichloroethane (DDT) was used extensively to control malaria, typhus, body lice, and bubonic plague worldwide, until countries began restricting its use in the 1970s. However, the use of DDT to control vector-borne diseases continues in developing countries. Prenatal DDT exposure is associated with elevated blood pressure in humans. Objective: We hypothesized that perinatal DDT exposure causes hypertension in adult mice. Methods: DDT was administered to C57BL/6J dams from gestational day 11.5 to postnatal day 5. Blood pressure (BP) and myocardial wall thickness were measured in male and female adult offspring. Adult mice were treated with an angiotensin converting enzyme (ACE) inhibitor, captopril, to evaluate sensitivity to amelioration of DDT-associated hypertension by ACE inhibition. We further assessed the influence of DDT exposure on the expression of mRNAs that regulate BP through renal ion transport. Results: Adult mice perinatally exposed to DDT exhibited chronically increased systolic BP, increased myocardial wall thickness, and elevated expression of mRNAs of several renal ion transporters. Captopril completely reversed hypertension in mice perinatally exposed to DDT. Conclusions: These data demonstrate that perinatal exposure to DDT causes hypertension and cardiac hypertrophy in adult offspring. A key mechanism underpinning this hypertension is an overactivated renin angiotensin system because ACE inhibition reverses the hypertension induced by perinatal DDT exposure. Citation: La Merrill M, Sethi S, Benard L, Moshier E, Haraldsson B, Buettner C. 2016. Perinatal DDT exposure induces hypertension and cardiac hypertrophy in adult mice. Environ Health Perspect 124:1722–1727; http://dx.doi.org/10.1289/EHP164

Hepatic steatosis is common in obesity and insulin resistance and results from a net retention of lipids in the liver. A key mechanism to prevent steatosis is to increase secretion of triglycerides (TG) packaged as VLDLs. Insulin controls nutrient partitioning via signaling through its cognate receptor in peripheral target organs such as liver, muscle, and adipose tissue and via signaling in the central nervous system (CNS) to orchestrate organ cross talk. While hepatic insulin signaling is known to suppress VLDL production from the liver, it is unknown whether brain insulin signaling independently regulates hepatic VLDL secretion. Here, we show that in conscious, unrestrained male Sprague Dawley rats the infusion of insulin into the third ventricle acutely increased hepatic TG secretion. Chronic infusion of insulin into the CNS via osmotic minipumps reduced the hepatic lipid content as assessed by noninvasive 1H-MRS and lipid profiling independent of changes in hepatic de novo lipogenesis and food intake. In mice that lack the insulin receptor in the brain, hepatic TG secretion was reduced compared with wild-type littermate controls. These studies identify brain insulin as an important permissive factor in hepatic VLDL secretion that protects against hepatic steatosis.

Targeted deletion of VGF, a secreted neuronal and endocrine peptide precursor, produces lean, hypermetabolic, and infertile mice that are resistant to diet-, lesion-, and genetically-induced obesity and diabetes. Previous studies suggest that VGF controls energy expenditure (EE), fat storage, and lipolysis, whereas VGF C-terminal peptides also regulate reproductive behavior and glucose homeostasis. To assess the functional equivalence of human VGF1–615 (hVGF) and mouse VGF1–617 (mVGF), and to elucidate the function of the VGF C-terminal region in the regulation of energy balance and susceptibility to obesity, we generated humanized VGF knockin mouse models expressing full-length hVGF or a C-terminally deleted human VGF1–524 (hSNP), encoded by a single nucleotide polymorphism (rs35400704). We show that homozygous male and female hVGF and hSNP mice are fertile. hVGF female mice had significantly increased body weight compared with wild-type mice, whereas hSNP mice have reduced adiposity, increased activity- and nonactivity-related EE, and improved glucose tolerance, indicating that VGF C-terminal peptides are not required for reproductive function, but 1 or more specific VGF C-terminal peptides are likely to be critical regulators of EE. Taken together, our results suggest that human and mouse VGF proteins are largely functionally conserved but that species-specific differences in VGF peptide function, perhaps a result of known differences in receptor binding affinity, likely alter the metabolic phenotype of hVGF compared with mVGF mice, and in hSNP mice in which several C-terminal VGF peptides are ablated, result in significantly increased activity- and nonactivity-related EE.

Proapoptotic BCL-2 proteins converge upon the outer mitochondrial membrane (OMM) to promote mitochondrial outer membrane permeabilization (MOMP) and apoptosis. Here we investigated the mechanistic relationship between mitochondrial shape and MOMP and provide evidence that BAX requires a distinct mitochondrial size to induce MOMP. We utilized the terminal unfolded protein response pathway to systematically define proapoptotic BCL-2 protein composition after stress and then directly interrogated their requirement for a productive mitochondrial size. Complementary biochemical, cellular, in vivo, and ex vivo studies reveal that Mfn1, a GTPase involved in mitochondrial fusion, establishes a mitochondrial size that is permissive for proapoptotic BCL-2 family function. Cells with hyperfragmented mitochondria, along with size-restricted OMM model systems, fail to support BAX-dependent membrane association and permeabilization due to an inability to stabilize BAXα9·membrane interactions. This work identifies a mechanistic contribution of mitochondrial size in dictating BAX activation, MOMP, and apoptosis.

Menopause is associated with bone loss and enhanced visceral adiposity. A polyclonal antibody that targets the β-subunit of the pituitary hormone follicle-stimulating hormone (Fsh) increases bone mass in mice. Here, we report that this antibody sharply reduces adipose tissue in wild-type mice, phenocopying genetic haploinsufficiency for the Fsh receptor gene Fshr. The antibody also causes profound beiging, increases cellular mitochondrial density, activates brown adipose tissue and enhances thermogenesis. These actions result from the specific binding of the antibody to the β-subunit of Fsh to block its action. Our studies uncover opportunities for simultaneously treating obesity and osteoporosis.

Context Nonalcoholic fatty liver disease and elevated circulating branched-chain amino acids (BCAAs) are common characteristics of obesity and type 2 diabetes. In rodents, brain insulin signaling controls both hepatic triglyceride secretion and BCAA catabolism. Whether brain insulin signaling controls similar metabolic pathways in humans is unknown. Objective Here we assessed if intranasal insulin, a method to preferentially deliver insulin to the central nervous system, is able to modulate hepatic lipid content and plasma BCAAs in humans. Design/Setting We conducted a randomized, double-blind, placebo-controlled trial at the Medical University of Vienna. Participants/Intervention We assessed if a chronic 4-week intranasal insulin treatment (40 IU, 4 times daily) reduces hepatic triglyceride content and circulating BCAAs in 20 healthy male volunteers. Main Outcome Measures Hepatic lipid content was assessed noninvasively by 1H-magnetic resonance spectroscopy, and BCAAs were measured by gas chromatography mass spectrometry at defined time points during the study. Results Chronic intranasal insulin treatment did not alter body weight, body mass index, and hepatic lipid content but reduced circulating BCAA levels. Conclusions These findings support the notion that brain insulin controls BCAA metabolism in humans. Thus, brain insulin resistance could account at least in part for the elevated BCAA levels observed in the insulin-resistant state.

Adaptive thermogenesis is the process of heat generation in response to cold stimulation. It is under the control of the sympathetic nervous system, whose chief effector is the catecholamine norepinephrine (NE). NE enhances thermogenesis through β3-adrenergic receptors to activate brown adipose tissue and by 'browning' white adipose tissue. Recent studies have reported that alternative activation of macrophages in response to interleukin (IL)-4 stimulation induces the expression of tyrosine hydroxylase (TH), a key enzyme in the catecholamine synthesis pathway, and that this activation provides an alternative source of locally produced catecholamines during the thermogenic process. Here we report that the deletion of Th in hematopoietic cells of adult mice neither alters energy expenditure upon cold exposure nor reduces browning in inguinal adipose tissue. Bone marrow-derived macrophages did not release NE in response to stimulation with IL-4, and conditioned media from IL-4-stimulated macrophages failed to induce expression of thermogenic genes, such as uncoupling protein 1 (Ucp1), in adipocytes cultured with the conditioned media. Furthermore, chronic treatment with IL-4 failed to increase energy expenditure in wild-type, Ucp1(-/-) and interleukin-4 receptor-α double-negative (Il4ra(-/-)) mice. In agreement with these findings, adipose-tissue-resident macrophages did not express TH. Thus, we conclude that alternatively activated macrophages do not synthesize relevant amounts of catecholamines, and hence, are not likely to have a direct role in adipocyte metabolism or adaptive thermogenesis.

SummaryCirculating branched-chain amino acid (BCAA) levels are elevated in obesity/diabetes and are a sensitive predictor for type 2 diabetes. Here we show in rats that insulin dose-dependently lowers plasma BCAA levels through induction of hepatic protein expression and activity of branched-chain α-keto acid dehydrogenase (BCKDH), the rate-limiting enzyme in the BCAA degradation pathway. Selective induction of hypothalamic insulin signaling in rats and genetic modulation of brain insulin receptors in mice demonstrate that brain insulin signaling is a major regulator of BCAA metabolism by inducing hepatic BCKDH. Short-term overfeeding impairs the ability of brain insulin to lower BCAAs in rats. High-fat feeding in nonhuman primates and obesity and/or diabetes in humans is associated with reduced BCKDH protein in liver. These findings support the concept that decreased hepatic BCKDH is a major cause of increased plasma BCAAs and that hypothalamic insulin resistance may account for impaired BCAA metabolism in obesity and diabetes.

Glucocorticoids (GCs) are critical in the regulation of the stress response, inflammation and energy homeostasis. Excessive GC exposure results in whole-body insulin resistance, obesity, cardiovascular disease, and ultimately decreased survival, despite their potent anti-inflammatory effects. This apparent paradox may be explained by the complex actions of GCs on adipose tissue functionality. The wide prevalence of oral GC therapy makes their adverse systemic effects an important yet incompletely understood clinical problem. This article reviews the mechanisms by which supraphysiologic GC exposure promotes insulin resistance, focusing in particular on the effects on adipose tissue function and lipid metabolism.

Context Inflammation contributes to the development of metabolic and cardiovascular disease. Cushing's disease (CD), a state of chronic glucocorticoid (GC) excess characterized by visceral obesity and insulin resistance, may be associated with increased systemic inflammation. Cardiovascular mortality in CD remains elevated even after successful remission. It is unclear if a chronic low grade inflammatory state persists even after remission of CD, which may account for the increased CVD mortality. Purpose 1) To assess circulating pro-inflammatory cytokines in active CD patients and BMI-matched controls; 2) to prospectively follow plasma cytokine concentrations in CD patients before and after surgical remission; and 3) to assess if plasma cytokine concentrations correlate with adipose tissue distribution and ectopic lipid content in liver and muscle. Methods Plasma cytokines from prospectively enrolled CD patients (N=31) were quantified during active disease (v1) vs. controls (N=18), and 19.5±12.9 months after surgical remission (v2). Fasting plasma IL-6, IL-1β, TNF-α, IL-8, IL-17 and IL-10 were quantified using a multiplex assay. Total and regional fat masses were measured by whole-body MRI. Results Circulating IL-6 and IL-1β were elevated in active CD patients vs. controls (p

Insulin controls fatty acid (FA) release from white adipose tissue (WAT) through direct effects on adipocytes and indirectly through hypothalamic signaling by reducing sympathetic nervous system outflow to WAT. Uncontrolled FA release from WAT promotes lipotoxicity, which is characterized by inflammation and insulin resistance that leads to and worsens type 2 diabetes. Here we tested whether early diet-induced insulin resistance impairs the ability of hypothalamic insulin to regulate WAT lipolysis and thus contributes to adipose tissue dysfunction. To this end we fed male Sprague-Dawley rats a 10% lard diet (high fat diet (HFD)) for 3 consecutive days, which is known to induce systemic insulin resistance. Rats were studied by euglycemic pancreatic clamps and concomitant infusion of either insulin or vehicle into the mediobasal hypothalamus. Short term HFD feeding led to a 37% increase in caloric intake and elevated base-line free FAs and insulin levels compared with rats fed regular chow. Overfeeding did not impair insulin signaling in WAT, but it abolished the ability of mediobasal hypothalamus insulin to suppress WAT lipolysis and hepatic glucose production as assessed by glycerol and glucose flux. HFD feeding also increased hypothalamic levels of the endocannabinoid 2-arachidonoylglycerol after only 3 days. In summary, overfeeding impairs hypothalamic insulin action, which may contribute to unrestrained lipolysis seen in human obesity and type 2 diabetes.

Osteoporosis is less common in individuals with high fat mass. This putative osteoprotection is likely an adaptive mechanism that allows obese individuals to better carry their increased body mass. Recent studies have focused on hormones that link fat to bone. Adipokines, such as leptin, modulate bone cells through both direct and indirect actions, whereas molecules activating peroxisome proliferator-activated receptor γ drive mesenchymal stem cell differentiation towards adipocytes away from the osteoblastic lineage. There is emerging evidence that bone-derived osteocalcin regulates insulin release and insulin sensitivity and, hence, might indirectly affect fat mass. Despite these molecular connections between fat and bone, animal and human studies call into question a primary role for body fat in determining bone mass. Mice devoid of fat do not have a skeletal phenotype, and in humans, the observed correlations between bone and body mass are not just due to adipose tissue. An improved understanding of the integrative physiology at the fat-bone interface should allow us develop therapies for both osteoporosis and obesity.

Dysregulation of endoplasmic reticulum (ER) Ca(2+) homeostasis triggers ER stress leading to the development of insulin resistance in obesity and diabetes. Impaired function of the sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) has emerged as a major contributor to ER stress. We pharmacologically activated SERCA2b in a genetic model of insulin resistance and type 2 diabetes (ob/ob mice) with a novel allosteric activator, CDN1163, which markedly lowered fasting blood glucose, improved glucose tolerance, and ameliorated hepatosteatosis but did not alter glucose levels or body weight in lean controls. Importantly, CDN1163-treated ob/ob mice maintained euglycemia comparable with that of lean mice for6 weeks after cessation of CDN1163 administration. CDN1163-treated ob/ob mice showed a significant reduction in adipose tissue weight with no change in lean mass, assessed by magnetic resonance imaging. They also showed an increase in energy expenditure using indirect calorimetry, which was accompanied by increased expression of uncoupling protein 1 (UCP1) and UCP3 in brown adipose tissue. CDN1163 treatment significantly reduced the hepatic expression of genes involved in gluconeogenesis and lipogenesis, attenuated ER stress response and ER stress-induced apoptosis, and improved mitochondrial biogenesis, possibly through SERCA2-mediated activation of AMP-activated protein kinase pathway. The findings suggest that SERCA2b activation may hold promise as an effective therapy for type-2 diabetes and metabolic dysfunction.

De novo lipogenesis (DNL), the synthesis of saturated and monounsaturated fatty acids from acetyl-CoA, occurs in most, if not all mammalian cell types. The liver and the adipose tissue are the major sites of DNL where excess nutrients are converted into DNL-derived fatty acids that then become the energy supply of other organs or are stored as triglycerides. DNL in the adipose tissue has been studied to a lesser extent than hepatic DNL. Similar to hepatic DNL, it appears that insulin and a systemic surplus of monosaccharides are powerful stimulants of DNL in white and brown adipose tissue. Although DNL in the liver and adipose tissues share regulatory mechanisms, adipose tissue DNL appears to be a marker of metabolic health whereas hepatic DNL often is increased in unfavorable metabolic states. Here we will discuss mechanisms orchestrating DNL in WAT and BAT and in the liver in physiology and the dysregulation of DNL in obesity and related disorders. We will also review several bioactive lipids that are products of adipose tissue DNL and their role in metabolic health.

Fatty acids released from white adipose tissue ( WAT) provide important energy substrates during fasting. However, uncontrolled fatty acid release from WAT during non-fasting states causes lipotoxicity and promotes inflammation and insulin resistance, which can lead to and worsen type 2 diabetes (DM2). WAT is also a source for insulin sensitizing fatty acids such as palmitoleate produced during de novo lipogenesis. Insulin and leptin are two major hormonal adiposity signals that control energy homeostasis through signaling in the central nervous system. Both hormones have been implicated to regulate both WAT lipolysis and de novo lipogenesis through the mediobasal hypothalamus (MBH) in an opposing fashion independent of their respective peripheral receptors. Here, we review the current literature on brain leptin and insulin action in regulating WAT metabolism and discuss potential mechanisms and neuro-anatomical substrates that could explain the opposing effects of central leptin and insulin. Finally, we discuss the role of impaired hypothalamic control of WAT metabolism in the pathogenesis of insulin resistance, metabolic inflexibility and type 2 diabetes.

OBJECTIVE The endocannabinoid (EC) system has been implicated as an important regulator of energy homeostasis. In obesity and type 2 diabetes, EC tone is elevated in peripheral tissues including liver, muscle, fat, and also centrally, particularly in the hypothalamus. Cannabinoid receptor type 1 (CB1) blockade with the centrally and peripherally acting rimonabant induces weight loss and improves glucose homeostasis while also causing psychiatric adverse effects. The relative contributions of peripheral versus central EC signaling on glucose homeostasis remain to be elucidated. The aim of this study was to test whether the central EC system regulates systemic glucose fluxes. RESEARCH DESIGN AND METHODS We determined glucose and lipid fluxes in male Sprague-Dawley rats during intracerebroventricular infusions of either WIN55,212-2 (WIN) or arachidonoyl-2'-chloroethylamide (ACEA) while controlling circulating insulin and glucose levels through hyperinsulinemic, euglycemic clamp studies. Conversely, we fed rats a high-fat diet for 3 days and then blocked central EC signaling with an intracerebroventricular infusion of rimonabant while assessing glucose fluxes during a clamp. RESULTS Central CB1 activation is sufficient to impair glucose homeostasis. Either WIN or ACEA infusions acutely impaired insulin action in both liver and adipose tissue. Conversely, in a model of overfeeding-induced insulin resistance, CB1 antagonism restored hepatic insulin sensitivity. CONCLUSIONS Thus central EC tone plays an important role in regulating hepatic and adipose tissue insulin action. These results indicate that peripherally restricted CB1 antagonists, which may lack psychiatric side effects, are also likely to be less effective than brain-permeable CB1 antagonists in ameliorating insulin resistance.

OBJECTIVE An increase in the rate of hepatic glucose production is the major determinant of fasting hyperglycemia in type 2 diabetes. A better understanding of the signaling pathways and molecules that regulate hepatic glucose metabolism is therefore of great clinical importance. Recent studies suggest that an increase in vagal outflow to the liver leads to decreased hepatic glucose production and reduced blood glucose levels. Since acetylcholine (ACh) is the major neurotransmitter of the vagus nerve and exerts its parasympathetic actions via activation of muscarinic ACh receptors (mAChRs), we examined the potential metabolic relevance of hepatocyte mAChRs. RESEARCH DESIGN AND METHODS We initially demonstrated that the M3 mAChR is the only mAChR subtype expressed by mouse liver/hepatocytes. To assess the physiological role of this receptor subtype in regulating hepatic glucose fluxes and glucose homeostasis in vivo, we used gene targeting and transgenic techniques to generate mutant mice lacking or overexpressing M3 receptors in hepatocytes only. RESULTS Strikingly, detailed in vivo phenotyping studies failed to reveal any significant metabolic differences between the M3 receptor mutant mice and their control littermates, independent of whether the mice were fed regular or a high-fat diet. Moreover, the expression levels of genes for various key transcription factors, signaling molecules, and enzymes regulating hepatic glucose fluxes were not significantly altered in the M3 receptor mutant mice. CONCLUSIONS This rather surprising finding suggests that the pronounced metabolic effects mediated by activation of hepatic vagal nerves are mediated by noncholinergic signaling pathways.

We report that oxytocin (OT), a primitive neurohypophyseal hormone, hitherto thought solely to modulate lactation and social bonding, is a direct regulator of bone mass. Deletion of OT or the OT receptor (Oxtr) in male or female mice causes osteoporosis resulting from reduced bone formation. Consistent with low bone formation, OT stimulates the differentiation of osteoblasts to a mineralizing phenotype by causing the up-regulation of BMP-2, which in turn controls Schnurri-2 and 3 , Osterix , and ATF-4 expression. In contrast, OT has dual effects on the osteoclast. It stimulates osteoclast formation both directly, by activating NF-κB and MAP kinase signaling, and indirectly through the up-regulation of RANK-L. On the other hand, OT inhibits bone resorption by mature osteoclasts by triggering cytosolic Ca 2+ release and NO synthesis. Together, the complementary genetic and pharmacologic approaches reveal OT as a novel anabolic regulator of bone mass, with potential implications for osteoporosis therapy.

Endocannabinoids (ECs) are small lipid mediators that play a critical role in energy metabolism. Human studies have shown that the EC tone in peripheral tissues positively correlates with increased adiposity. Furthermore, pharmacological inhibition of EC signaling results in weight loss in humans. However, the mechanisms that cause the dysregulation of the EC system in obesity are not well-understood. Since the clinical utility of currently available EC blockers is severely limited due to their side effects like depression and suicidal ideation that are caused by central effects, it is important to delineate the role of central and peripheral effects of EC signaling in regulating glucose and lipid metabolism.

The liver plays a pivotal role in the regulation of glucose metabolism because it is the key organ that maintains glucose levels during fasting. An emerging body of literature has demonstrated the important role of the hypothalamus in controlling hepatic glucose production (HGP). The hypothalamus senses circulating nutrients and hormones, conveying the energy status to the central nervous system, which, in turn, controls HGP in part by way of the autonomic nervous system. Overfeeding results in the failure of the hypothalamus to sense circulating nutrients and hormones, and in a loss of the central control of HGP.

Introduction Insulin resistance and type 2 diabetes mellitus (T2D) are associated with increased risk for cognitive impairment, Alzheimer’s disease (AD) and vascular dementia. SORCS1 encodes a protein-sorting molecule genetically linked to both T2D and AD. The association of SORCS1 with both AD and T2D is sexually dimorphic in humans, with both disease associations showing more robust effects in females. Based on published evidence that manipulation of the mouse genome combining multiple genes related to cerebral amyloidosis, to T2D, or both, might provide novel mouse models with exacerbated amyloid and/or diabetes phenotypes, we assessed memory, glucose homeostasis, and brain biochemistry and pathology in male and female wild-type, Sorcs1 -/-, APP/PSEN1, and Sorcs1 -/- X APP/PSEN1 mice. Results Male mice with either the APP/PSEN1 or Sorcs1 -/- genotype displayed earlier onset and persistent impairment in both learning behavior and glucose homeostasis. Unlike prior examples in the literature, the behavioral and metabolic abnormalities in male mice were not significantly exacerbated when the two disease model mice (Sorcs1 -/- models T2D; APP/PSEN1 models AD) were crossed. However, female Sorcs1 -/- X APP/PSEN1 mice exhibited worse metabolic dysfunction than Sorcs1 -/- knockout mice and worse memory than wild-type mice. The deletion of Sorcs1 from APP/PSEN1 mutant mice led to no obvious changes in brain levels of total or oligomeric amyloid-beta (Aβ) peptide. Conclusions In general, unexpectedly, there was a trend for gene targeting of Sorcs1-/- to partially mitigate, not exacerbate, the metabolic and amyloid pathologies. These results indicate that crossing AD model mice and T2D model mice may not always cause exacerbation of both the amyloidosis phenotype and the metabolic phenotype and highlight the unexpected pitfalls of creating mixed models of disease. Electronic supplementary material The online version of this article (doi:10.1186/s40478-016-0282-y) contains supplementary material, which is available to authorized users.

Introduction Epidemiologic studies have demonstrated an association between diabetes and dementia. Insulin signaling within the brain, in particular within the hypothalamus regulates carbohydrate, lipid, and branched chain amino acid (BCAA) metabolism in peripheral organs such as the liver and adipose tissue. We hypothesized that cerebral amyloidosis impairs central nervous system control of metabolism through disruption of insulin signaling in the hypothalamus, which dysregulates glucose and BCAA homeostasis resulting in increased susceptibility to diabetes. Methods We examined whether APP/PS1 mice exhibit increased susceptibility to aging or high-fat diet (HFD)-induced metabolic impairment using metabolic phenotyping and insulin-signaling studies. Results APP/PS1 mice were more susceptible to high-fat feeding and aging-induced metabolic dysregulation including disrupted BCAA homeostasis and exhibited impaired hypothalamic insulin signaling. Discussion Our data suggest that AD pathology increases susceptibility to diabetes due to impaired hypothalamic insulin signaling, and that plasma BCAA levels could serve as a biomarker of hypothalamic insulin action in patients with AD.

SummaryLeptin has pleiotropic effects on glucose homeostasis and feeding behavior. Here, we validate the use of a cell-permeable phosphopeptide that blocks STAT3 activation in vivo. The combination of this biochemical approach with stereotaxic surgical techniques allowed us to pinpoint the contribution of hypothalamic STAT3 to the acute effects of leptin on food intake and glucose homeostasis. Leptin's ability to acutely reduce food intake critically depends on intact STAT3 signaling. Likewise, hypothalamic signaling of leptin through STAT3 is required for the acute effects of leptin on liver glucose fluxes. Lifelong obliteration of STAT3 signaling via the leptin receptor in mice (s/s mice) results in severe hepatic insulin resistance that is comparable to that observed in db/db mice, devoid of leptin receptor signaling. Our results demonstrate that the activation of the hypothalamic STAT3 pathway is an absolute requirement for the effects of leptin on food intake and hepatic glucose metabolism.

A variety of human cancers, including nonsmall cell lung (NSCLC), breast, and colon cancers, are driven by the human epidermal growth factor receptor (HER) family of receptor tyrosine kinases. Having shown that bisphosphonates, a class of drugs used widely for the therapy of osteoporosis and metastatic bone disease, reduce cancer cell viability by targeting HER1, we explored their potential utility in the prevention and therapy of HER-driven cancers. We show that bisphosphonates inhibit colony formation by HER1(ΔE746-A750)-driven HCC827 NSCLCs and HER1(wt)-expressing MB231 triple negative breast cancers, but not by HER(low)-SW620 colon cancers. In parallel, oral gavage with bisphosphonates of mice xenografted with HCC827 or MB231 cells led to a significant reduction in tumor volume in both treatment and prevention protocols. This result was not seen with mice harboring HER(low) SW620 xenografts. We next explored whether bisphosphonates can serve as adjunctive therapies to tyrosine kinase inhibitors (TKIs), namely gefitinib and erlotinib, and whether the drugs can target TKI-resistant NSCLCs. In silico docking, together with molecular dynamics and anisotropic network modeling, showed that bisphosphonates bind to TKIs within the HER1 kinase domain. As predicted from this combinatorial binding, bisphosphonates enhanced the effects of TKIs in reducing cell viability and driving tumor regression in mice. Impressively, the drugs also overcame erlotinib resistance acquired through the gatekeeper mutation T790M, thus offering an option for TKI-resistant NSCLCs. We suggest that bisphosphonates can potentially be repurposed for the prevention and adjunctive therapy of HER1-driven cancers.

Insulin exerts its potent effects on hepatic glucose fluxes via direct and indirect mechanisms. Whereas a liver-specific insulin receptor (IR) knockout (LIRKO) mouse exhibits glucose intolerance as well as insulin resistance, it is unclear whether a more acute decrease in the expression of hepatic IR would be sufficient to induce hepatic insulin resistance. Here we report that the downregulation of hepatic IR expression by up to 95% does not modify hepatic insulin action. The i.p. administration (2 injections over 1 week) of an antisense oligodeoxynucleotide (ASO) directed to reduce insulin expression downregulated hepatic IR expression in C57BL6J mice. A high dose of IR-ASO decreased IR protein approximately 95%, while a control-ASO failed to modify IR expression. At this dose, the IR-ASO also decreased IR expression in adipose tissue but did not significantly decrease IR expression in hypothalamus or skeletal muscle. Insulin action was assessed with insulin clamp studies in conscious mice. The rate of glucose infusion during the clamp studies was comparable in control-ASO- and IR-ASO-treated mice. Importantly, the depletion of liver IR protein markedly impaired downstream insulin signaling in the liver, but it failed to modify the rate of glucose production. Thus, near ablation of liver IR does not alter insulin action on glucose production.