Mechanisms of glucocorticoid-induced insulin resistance: focus on adipose tissue function and lipid metabolism

The glucocorticoid receptor agonistic modulators CpdX and CpdX-D3 do not generate the debilitating effects of synthetic glucocorticoids

Seventy years after the discovery of their anti-inflammatory properties, glucocorticoids (GCs) remain the mainstay treatment for major allergic and inflammatory disorders, such as atopic dermatitis, asthma, rheumatoid arthritis, colitis, and conjunctivitis, among others. However, their long-term therapeutical administration is limited by major debilitating side effects, e.g., skin atrophy, osteoporosis, Addison-like adrenal insufficiency, fatty liver, and type 2 diabetes syndrome, as well as growth inhibition in children. These undesirable side effects are mostly related to GC-induced activation of both the direct transactivation and the direct transrepression functions of the GC receptor (GR), whereas the activation of its GC-induced indirect tethered transrepression function results in beneficial anti-inflammatory effects. We have reported in the accompanying paper that the nonsteroidal compound CpdX as well as its deuterated form CpdX-D3 selectively activate the GR indirect transrepression function and are as effective as synthetic GCs at repressing inflammations generated in several mouse models of major pathologies. We now demonstrate that these CpdX compounds are bona fide selective GC receptor agonistic modulators (SEGRAMs) as none of the known GC-induced debilitating side effects were observed in the mouse upon 3-mo CpdX treatments. We notably report that, unlike that of GCs, the administration of CpdX to ovariectomized (OVX) mice does not induce a fatty liver nor type 2 diabetes, which indicates that CpdX could be used in postmenopausal women as an efficient "harmless" GC substitute.

Management of hyperglycaemia in persons with non-insulin-dependent type 2 diabetes mellitus who are started on systemic glucocorticoid therapy: a systematic review

OBJECTIVES

What is the most effective pharmacological intervention for glycaemic control in known type 2 diabetes mellitus (DM) without prior insulin treatment and newly started on systemic glucocorticoid therapy?

DESIGN

We conducted a systematic literature review.

DATA SOURCES

We searched MEDLINE, Embase and Cochrane Library databases and Google for articles from 2002 to July 2018.

ELIGIBILITY CRITERIA

We combined search terms relating to DM (patients, >16 years of age), systemic glucocorticoids, glycaemic control, randomised controlled trials (RCTs) and observational studies.

DATA EXTRACTION AND SYNTHESIS

We screened and evaluated articles, extracted data and assessed risk of bias and quality of evidence according to Grading of Recommendations Assessment, Development and Evaluation guidelines.

RESULTS

Eight of 2365 articles met full eligibility criteria. Basal-bolus insulin (BBI) strategy for patients under systemic glucocorticoid therapy was comparatively effective but provided insufficient glucose control, depending on time of day. BBI strategy with long-acting insulin and neutral protamin Hagedorn as basal insulin provided similar overall glycaemic control. Addition of various insulin strategies to standard BBI delivered mixed results. Intermediate-acting insulin (IMI) as additional insulin conferred no clear benefits, and glycaemic control with sliding scale insulin was inferior to BBI or IMI. No studies addressed whether anticipatory or compensatory insulin adjustments are better for glycaemic control.

CONCLUSION

The lack of suitably designed RCTs and observational studies, heterogeneity of interventions, target glucose levels and glucose monitoring, poor control of DM subgroups and low to moderate quality of evidence render identification of optimal pharmacological interventions for glycaemic control and insulin management difficult. Even findings on the widely recommended BBI regimen as intensive insulin therapy for patients with DM on glucocorticoids are inconclusive. High-quality evidence from studies with well-defined DM phenotypes, settings and treatment approaches is needed to determine optimal pharmacological intervention for glycaemic control.

PROSPERO REGISTRATION NUMBER

CRD42015024739.

Loss of the glucocorticoid receptor in zebrafish improves muscle glucose availability and increases growth

Chronic stress and the associated elevation in corticosteroid levels increase muscle protein catabolism. We hypothesized that the glucocorticoid receptor (GR)-regulated restriction of muscle glucose availability may play a role in the increased protein catabolism during chronic stress. To test this, we generated a ubiquitous GR knockout (GRKO) zebrafish to determine the physiological consequence of glucocorticoid stimulation on muscle metabolism and growth. Adult GRKO zebrafish had higher body mass, and this corresponded to an increased protein and lipid, but not carbohydrate, content. GRKO fish were hypercortisolemic, but they elicited a higher cortisol response to an acute stressor. However, the stressor-induced increase in plasma glucose level observed in the wild type was completely abolished in the GRKO fish. Also, the muscle, but not liver, capacity for glucose uptake was enhanced in the GRKO fish, and this corresponded with a higher hexokinase activity in the mutants. Zebrafish lacking GR also showed a higher capacity for protein synthesis, including increased phosphorylation of eukaryotic initiation factor 4B, higher expression of heat shock protein cognate 70, and total protein content. A chronic fasting stressor reduced body mass and muscle protein content in adult zebrafish, but this decrease was attenuated in the GRKO compared with the wild-type fish. Metabolomics analysis revealed that the free pool of amino acid substrates used for oxidation and gluconeogenesis were lower in the fasted GRKO fish muscle compared with the wild type. Altogether, chronic stressor-mediated GR signaling limits muscle glucose uptake, and this may play a role in protein catabolism, leading to the growth suppression in fish.

Redox TRPs in diabetes and diabetic complications: Mechanisms and pharmacological modulation

Transient receptor potential (TRP) channels have shown to be involved in a wide variety of physiological functions and pathophysiological conditions. Modulation of TRP channels reported to play a major role in number of disorders starting from central nervous system related disorders to cardiovascular, inflammatory, cancer, gastrointestinal and metabolic diseases. Recently, a subset of TRP ion channels called redox TRPs gained importance on account of their ability to sense the cellular redox environment and respond accordingly to such redox stimuli. Diabetes, the silent epidemic of the world is increasing at an alarming rate in spite of novel therapeutic interventions. Moreover, diabetes and its associated complications are reported to arise due to a change in oxidative status of cell induced by hyperglycemia. Such a change in cellular oxidative status can modulate the activities of various redox TRP channels (TRPA1, TRPC5, TRPMs and TRPV1). Targeting redox TRPs have potential in diabetes and diabetic complications like neuropathy, cardiomyopathy, retinopathy, cystopathy, and encephalopathy. Thus in this review, we have discussed the activities of different redox sensing TRPs in diabetes and diabetic complications and how they can be modulated pharmacologically, so as to consider them a potential novel therapeutic target in treating diabetes and its comorbidity.

Five-year incidence of common comorbidities, such as hypertension, dyslipidemia, diabetes mellitus, cardiovascular disease, cerebrovascular disease and cancer, in older Japanese patients with rheumatoid arthritis

AIM

To estimate the 5-year incidence of common comorbidities, including lifestyle-associated diseases, in older Japanese patients with rheumatoid arthritis (RA).

METHODS

We enrolled 129 consecutive patients with RA aged ≥65 years in this study. We examined all patients for the presence of hypertension, dyslipidemia, diabetes mellitus, cardiovascular disease, cerebrovascular disease and cancer at baseline (in 2013) and 5 years later (in 2018) using clinical records, self-reported questionnaires, interviews and medication records.

RESULTS

At baseline, hypertension was prevalent in 37.2% of the patients, dyslipidemia in 18.6%, diabetes mellitus in 9.3%, cardiovascular disease in 14.7%, cerebrovascular disease in 10.1% and cancer in 10.1%. Furthermore, the change of prevalence after 5 years from baseline of hypertension, dyslipidemia, diabetes mellitus, cardiovascular disease, cerebrovascular disease and cancer was 4.6%, 3.9%, 0.8%, 4.7%, 2.3% and 1.5%, respectively. The factors associated at baseline and/or after 5 years of hypertension, dyslipidemia, diabetes mellitus, cardiovascular disease and cancer included disease duration and body mass index, body mass index and anti-cyclic citrullinated peptide antibody, corticosteroid use, body mass index, and male and disease duration, respectively.

CONCLUSIONS

The Japanese population is aging and so is the population of patients with RA. In older patients with RA, hypertension and cardiovascular disease should be particularly considered. Therefore, although the therapeutic agents for RA have improved, a better understanding of the comorbidities in older patients with RA should impact the treatment of RA. Geriatr Gerontol Int 2019; 19: 577-581.

Acute stress response to a cognitive task in patients with major depressive disorder: potential metabolic and proinflammatory biomarkers

Responses of the hypothalamic-pituitary-adrenal axis (HPAA), immune system and metabolic pathways are involved in adaptation to stress, while alterations in these responses have been implicated in the development of major depressive disorder (MDD). Multiple laboratory indices are known to react in response to the acute stress, however, no valid biomarkers have been reported, which can differentiate stress response in depressed individuals. The aim of this study was to assess changes in a set of laboratory parameters in patients with MDD in response to a moderate mental stress and to find potential markers of altered stress reactivity associated with depression. A group of 33 MDD patients and 43 control subjects underwent clinical evaluation to assess depression and anxiety symptoms, as well as heart rate variability (HRV) analysis. Participants were asked to perform a time constrained cognitive task, and selected hormones (cortisol, ACTH), cytokines (IL-6, IL-1β, TNF-α), neurotrophic factors (BDNF, CNTF) and metabolic parameters (glucose, cholesterol, triglycerides) were measured before and 60 min after the task performance. HRV analysis showed increased sympathetic input in MDD patients. The MDD group manifested an elevated HPAA activity as well as IL-6 and CNTF levels at baseline. A specific stress-induced increase in glucose and TNF-α was revealed in the MDD group, which was absent in control subjects. The data confirm the impairments of stress response in MDD and suggest that the reaction of simple metabolic and pro-inflammatory indices to a mild stressogenic challenge may be indicative of a depressive state.

Adipose glucocorticoid action influences whole-body metabolism via modulation of hepatic insulin action

The connection between adipose glucocorticoid action and whole-body metabolism is incompletely understood. Thus, we generated adipose tissue-specific glucocorticoid receptor-knockout (Ad-GcR^-/-) mice to explore potential mechanisms. Ad-GcR^-/- mice had a lower concentration of fasting plasma nonesterified fatty acids and less hepatic steatosis. This was associated with increased protein kinase B phosphorylation and increased hepatic glycogen synthesis after an oral glucose challenge. High-fat diet (HFD)-fed Ad-GcR^-/- mice were protected against the development of hepatic steatosis and diacylglycerol-PKCε-induced impairments in hepatic insulin signaling. Under hyperinsulinemic-euglycemic conditions, hepatic insulin response was ∼10-fold higher in HFD-fed Ad-GcR^-/- mice. Insulin-mediated suppression of adipose lipolysis was improved by 40% in Ad-GcR^-/- mice. Adipose triglyceride lipase expression was decreased and insulin-mediated perilipin dephosphorylation was increased in Ad-GcR^-/- mice. In metabolic cages, food intake decreased by 3 kcal/kg per hour in Ad-GcR^-/- mice. Therefore, physiologic adipose glucocorticoid action appears to drive hepatic lipid accumulation during stressors such as fasting. The resultant hepatic insulin resistance prevents hepatic glycogen synthesis, preserving glucose for glucose-dependent organs. Absence of adipose glucocorticoid action attenuates HFD-induced hepatic insulin resistance; potential explanations for reduction in hepatic steatosis include reductions in adipose lipolysis and food intake.-Abulizi, A., Camporez, J.-P., Jurczak, M. J., Høyer, K. F., Zhang, D., Cline, G. W., Samuel, V. T., Shulman, G. I., Vatner, D. F. Adipose glucocorticoid action influences whole-body metabolism via modulation of hepatic insulin action.

Coumarins ameliorate diabetogenic action of dexamethasone via Akt activation and AMPK signaling in skeletal muscle

Glucocorticoids are widely prescribed for lots of pathological conditions, however, can produce 'Cushingoid' side effects including central obesity, glucose intolerance, insulin resistance and so forth. Our study is intended to investigate the improving effects of coumarins on diabetogenic action of dexamethasone in vivo and in vitro and elucidate potential mechanisms. ICR mice treated with dexamethasone for 21 days exhibited decreased body weight, increased blood glucose and impaired glucose tolerance, which were prevented by fraxetin (40 mg/kg/day), esculin (40 mg/kg/day) and osthole (20 mg/kg/day), respectively. Esculin, fraxetin and osthole also could promote glucose uptake in normal C2C12 myotubes, and improve insulin resistance in myotubes induced by dexamethasone. Western blotting results indicated that esculin, fraxetin and osthole could boost Akt activation, stimulate GLUT4 translocation, thus alleviate insulin resistance. Esculin and osthole also could activate AMPK, thereby phosphorylate TBC1D1 at Ser237, and consequently ameliorate diabetogenic action of dexamethasone. Our study indicates coumarins as potential anti-diabetic candidates or leading compounds for drug development.

Aspalathus linearis (Rooibos) - a functional food targeting cardiovascular disease

Increasing consumer bias toward natural products and the considerable wealth of indigenous knowledge has precipitated an upturn in market-driven research into potentially beneficial medicinal plants. In this context, Aspalathus linearis (Rooibos) has been identified to be a promising candidate which may impact cardiovascular disease (CVD), which is one of the most widely studied chronic diseases of modern times. Despite these efforts, ischemic heart disease remains the number one cause of mortality globally. Apart from genetic predisposition and other aetiological mechanisms specific to particular types of CVD, co-factors from interlinked systems contribute significantly to disease development and the severity of its clinical manifestation. The bioactivity of Rooibos is directed towards multiple therapeutic targets. Experimental data to date include antioxidant, anti-inflammatory and anti-diabetic effects, as well as modulatory effects in terms of the immune system, adrenal steroidogenesis and lipid metabolism. This review integrates relevant literature on the therapeutic potential of Rooibos in the context of CVD, which is currently the most common of non-communicable diseases. The therapeutic value of whole plant extracts versus isolated active ingredients are addressed, together with the potential for overdose or herb-drug interaction. The body of research undertaken to date clearly underlines the benefits of Rooibos as both preventative and complementary therapeutic functional food in the context of CVD.

Obesity as the Main Risk Factor for Metabolic Syndrome in Children

Obesity in childhood is the main determinant of whole body reduced insulin sensitivity. This association has been demonstrated in multiple adult and pediatric cohorts. The mechanistic link explaining this association is the pattern of lipid partitioning in the face of excess calories and energy surplus. A tight relation exists between typical lipid deposition patterns, specifically within the skeletal muscle and liver, as well as the intra-abdominal compartment and whole body insulin sensitivity. The impact of lipid deposition within insulin responsive tissues such as the liver and skeletal muscle relates to the ability of fatty acid derivates to inhibit elements of the insulin signal transduction pathway. Strengthening the relation of obesity and reduced insulin sensitivity are the observations that weight gain reduces insulin sensitivity while weight loss increases it. This manifests as the appearance of cardiovascular risk factor clustering with weight gain and its recovery in the face of weight loss. Both obesity per se, via the adipocytokine profile it induces, and low insulin sensitivity, are independent determinants of the adverse metabolic phenotype characteristic of the metabolic syndrome.

Inter-tissue communication in cancer cachexia

Cachexia is a systemic condition that occurs during many neoplastic diseases, such as cancer. Cachexia in cancer is characterized by loss of body weight and muscle and by adipose tissue wasting and systemic inflammation. Cancer cachexia is often associated with anorexia and increased energy expenditure. Even though the cachectic condition severely affects skeletal muscle, a tissue that accounts for ~40% of total body weight, it represents a multi-organ syndrome that involves tissues and organs such as white adipose tissue, brown adipose tissue, bone, brain, liver, gut and heart. Indeed, evidence suggests that non-muscle tissues and organs, as well as tumour tissues, secrete soluble factors that act on skeletal muscle to promote wasting. In addition, muscle tissue also releases various factors that can interact with the metabolism of other tissues during cancer. In this Review, we examine the effect of non-muscle tissues and inter-tissue communication in cancer cachexia and discuss studies aimed at developing novel therapeutic strategies for the condition.

Dynamic changes in the distribution of facial and abdominal adipose tissue correlated with surgical treatment in acromegaly

PURPOSE

Acromegaly is a systemic metabolic disease. Growth hormone (GH) have a significant impact on adipose tissue (AT). A huge reduction of serum GH after surgical treatment may cause substantial AT redistribution. The objective of this study was to illustrate the dynamic changes in distribution of facial and abdominal AT correlated with surgical treatment in patients with acromegaly.

METHODS

Abdominal AT in 17 acromegaly patients (group 1) was studied longitudinally preoperatively and 1 month to 1 year postoperatively. The facial and abdominal subcutaneous AT (fSAT and aSAT) of another 17 acromegaly patients (group 2) were compared with 7 nonfunctional pituitary adenoma (NFPA) controls. The areas of fSAT, aSAT, and visceral adipose tissue (VAT) were obtained by MRI and quantified by image analysis software, and intrahepatic lipid (IHL) was assessed by 1H magnetic resonance spectroscopy (MRS).

RESULTS

Abdominal adipose tissue (aSAT, VAT, and IHL) increased overall after surgical treatment. However, IHL first decreased and then continuously increased during the follow-up. Compared with the increased amount of aSAT, the fSAT amount decreased after surgical treatment. The inconsistency of this phenomenon did not appear in the NFPA control subjects.

CONCLUSION

The perioperative dynamic distribution of the facial and abdominal fat in acromegaly revealed regional differences in the intricate effect of GH on adipose tissue. Reduction of serum GH after surgical treatment of acromegaly was associated with dynamic increases of IHL, abdominal visceral, and subcutaneous fat, but a reduction of facial subcutaneous fat.

Diurnal profile of interstitial glucose following dexamethasone prophylaxis for chemotherapy treatment of gynaecological cancer

AIMS

Hyperglycaemia, a side-effect of acute glucocorticoid exposure, is associated with poor outcome in those undergoing chemotherapy. The incidence, risk factors and diurnal profile of glucocorticoid-induced glucose dysregulation in the context of chemotherapy treatment remain incompletely understood.

METHODS

Blinded continuous interstitial glucose monitoring was performed on 16 women without diabetes for 24 h prior to and 5 days following carboplatin/paclitaxel chemotherapy combined with dexamethasone treatment for gynaecological cancer. At the end of the treatment period, glucose data were analysed and integrated with baseline metabolic and anthropomorphic variables.

RESULTS

15/16 (94%) women exhibited elevated glucose levels (> 11.1 mmol/l). Peak glucose levels were highest on the day of treatment (median 14.45 mmol/l, range 10.2-22.2 mmol/l) and total time spent with an elevated interstitial glucose level was highly variable (median 3.6 h, range 0.0-55.1 h). Peak interstitial glucose levels occurred predominantly, but not exclusively, in the afternoon (13.00-15.00) and evening (19.00-22.00); however elevated levels were noted throughout the 24-h period. Baseline HbA_1c was independently associated with severity and duration of elevated glucose levels in a regression adjusted for baseline BMI.

CONCLUSIONS

These data report for the first time that high glucose levels are encountered by nearly all women following this regimen, the severity and duration of which are independently associated with HbA_1c . Further work is required to determine if controlling glucose levels during treatment influences outcome.

Psychological stress and type 1 diabetes mellitus: what is the link?

INTRODUCTION

Type 1 diabetes mellitus (T1DM) is a chronic disease characterized by the destruction of insulin-producing β-cells of the pancreas. The current paradigm in this disease's etiopathogenesis points toward the interplay of genetic and environmental factors. Among the environmental variables, dietary factors, intestinal microbiota, toxins, and psychological stress have been implicated in disease onset. Areas covered: This review aims to investigate the relationship between psychological stress and T1DM by presenting evidence from epidemiological studies, animal models, and to provide the mechanism involved in this association. The literature search was conducted through PubMed to identify studies that investigate the connection between stress and T1DM. Experimental designs, such as case-control, and retrospective and prospective cohorts studies, were included. Expert commentary: A wide array of evidence, ranging from epidemiological to animal models, points toward the role of psychological stressors in T1DM pathogenesis. Various mechanisms have been proposed, including the hypothalamic-pituitary-adrenal (HPA) axis, influence of the nervous system on immune cells, and insulin resistance. Further research could investigate the gene-stress interactions to evaluate the risk of T1DM development.

Cognitive effects of mifepristone in overweight, euthymic adults with depressive disorders

BACKGROUND

Previous studies have shown that individuals with mood disorders have a higher prevalence of both hypercortisolemia and insulin resistance. Insulin resistance is posited to contribute to the cognitive deficits observed in individuals who have depression. However, the mechanistic relationship between cortisol and insulin within the central nervous system remains to be further elucidated. This study aimed to evaluate the effects of the antiglucocorticoid agent, mifepristone, on metabolic function and cognitive performance in individuals receiving treatment for depressive disorders who were euthymic at baseline.

METHODS

Participants were administered a 600 mg/day dose of mifepristone for 28 days. Oral glucose tolerance tests (OGTTs) and cognitive assessments measuring verbal memory and executive functioning were administered at baseline and after 28 days of treatment.

RESULTS

Improvements in attention and verbal learning were associated with reduction of fasting plasma glucose (FPG) in response to mifepristone treatment.

LIMITATIONS

Limitations include the open-label design of this study and a small sample size.

CONCLUSIONS

The findings from this study suggest that improvement in fasting plasma glucose levels, upon administration of mifepristone, is associated with the improvement in early input of verbal information. Further studies are warranted in order to better evaluate the use of mifepristone or other antiglucocorticoid agents in treatment of mood disorders characterized by metabolic dysfunction.

FKBP5 expression in human adipose tissue: potential role in glucose and lipid metabolism, adipogenesis and type 2 diabetes

PURPOSE

Here, we explore the involvement of FKBP51 in glucocorticoid-induced insulin resistance (IR) in human subcutaneous adipose tissue (SAT), including its potential role in type 2 diabetes (T2D). Moreover, we assess the metabolic effects of reducing the activity of FKBP51 using the specific inhibitor SAFit1.

METHODS

Human SAT was obtained by needle biopsies of the lower abdominal region. FKBP5 gene expression was assessed in fresh SAT explants from a cohort of 20 T2D subjects group-wise matched by gender, age and BMI to 20 non-diabetic subjects. In addition, human SAT was obtained from non-diabetic volunteers (20F/9M). SAT was incubated for 24 h with or without the synthetic glucocorticoid dexamethasone and SAFit1. Incubated SAT was used to measure the glucose uptake rate in isolated adipocytes.

RESULTS

FKBP5 gene expression levels in SAT positively correlated with several indices of IR as well as glucose area under the curve during oral glucose tolerance test (r = 0.33, p < 0.05). FKBP5 gene expression levels tended to be higher in T2D subjects compared to non-diabetic subjects (p = 0.088). Moreover, FKBP5 gene expression levels were found to inversely correlate with lipolytic, lipogenic and adipogenic genes. SAFit1 partly prevented the inhibitory effects of dexamethasone on glucose uptake.

CONCLUSIONS

FKBP5 gene expression in human SAT tends to be increased in T2D subjects and is related to elevated glucose levels. Moreover, FKBP5 gene expression is inversely associated with the expression of lipolytic, lipogenic and adipogenic genes. SAFit1 can partly prevent glucose uptake impairment by glucocorticoids, suggesting that FKBP51 might be a key factor in glucocorticoid-induced IR.

Management of hyperglycaemia and steroid (glucocorticoid) therapy: a guideline from the Joint British Diabetes Societies (JBDS) for Inpatient Care group

Glucocorticoids (steroids) are widely used across many medical specialities for their anti-inflammatory and immunosuppressive properties. However, one of their major side effects is the development of hyperglycaemia. It is well recognized that high glucose levels in people with diabetes in hospital are associated with harm and increased lengths of hospital stay. The use of glucocorticoid (steroid) treatment in people with pre-existing diabetes will undoubtedly result in worsening glucose control, and this may be termed 'steroid-induced hyperglycaemia', and will warrant temporary additional, and more active, glycaemic management. A rise in glucose may occur in people without a known diagnosis of diabetes, and this may be termed 'steroid-induced diabetes'. There is a lack of evidence to guide how people with hyperglycaemia should be managed, and much of the guidance given here is a consensus based on best practice collated from around the United Kingdom. Where evidence is available, this is referenced. These guidelines on the management of people with diabetes treated with steroids has been adapted specifically for Diabetic Medicine. The full version of the guidelines can be found on line at: www.diabetes.org.uk/joint-british-diabetes-society or https://abcd.care/joint-british-diabetes-societies-jbds-inpatient-care-group.

Physiopathological relationship between chronic obstructive pulmonary disease and insulin resistance

PURPOSE

Chronic obstructive pulmonary disease (COPD) is characterized by persistent and progressive airflow obstruction that is associated with an abnormal chronic inflammatory response in the airways and lungs to noxious particles. COPD often leads to physical inactivity and deconditioning that added to inappropriate/excessive inflammatory responses leads to systemic consequences. Studies have shown that metabolic syndrome and manifested diabetes are more frequent in COPD than in healthy subjects; a possible explanation is that different pathophysiological aspects of COPD can lead to insulin resistance. Thus, this mini-review aims to present the main studies suggesting a pathophysiological relationship between COPD and insulin resistance.

METHODS

A review of literature was conducted using PubMed and Web of Science databases with the aim of searching for studies supporting a relationship between COPD and insulin resistance.

RESULTS

A physiopathological relationship between COPD and insulin resistance was found, supported in part due to common risk factors presented by these two conditions, such as smoking and physical inactivity. Also, systemic effects (worsening of physical inactivity and sedentary behavior, inflammation and oxidative stress, body composition abnormalities) and the corticosteroid treatment of patients with COPD may play a role.

CONCLUSION

Patients with COPD should be screened for abnormalities in insulin sensitivity in order to reduce morbidity and improve health status in this population.

Local Cortisol Elevation Contributes to Endometrial Insulin Resistance in Polycystic Ovary Syndrome

CONTEXT

Endometrial insulin resistance (IR) may account for the endometrial dysfunction in polycystic ovary syndrome (PCOS). The underlying mechanism remains to be elucidated.

OBJECTIVE

To investigate whether the abundance of 11β-hydroxysteroid dehydrogenases (11β-HSDs) 1 and 2 and cortisol as well as the insulin signaling pathway are altered in PCOS endometrium and to clarify the relationship between endometrial IR and local cortisol.

DESIGN

We measured cortisol and cortisone concentrations, 11β-HSD1 and 11β-HSD2, and core insulin signaling molecules in endometrial biopsies collected from non-PCOS and PCOS with or without IR patients on the seventh day after human chorionic gonadotropin injection. We also studied the effects of cortisol on glucose uptake and the insulin signaling pathway in primary cultured endometrial epithelial cells (EECs).

RESULTS

The cortisol concentration was elevated, whereas 11β-HSD2 expression was diminished in endometrial biopsies obtained from PCOS with IR patients compared with those from non-PCOS and PCOS without IR patients. The implantation rate was relatively impaired and the endometrial insulin signaling pathway was defective in PCOS with IR patients. In addition, cortisol attenuated insulin-stimulated glucose uptake in EECs, which was mediated by inhibition of Akt phosphorylation and glucose transporter type 4 translocation via induction of phosphatase and tensin homolog deleted on chromosome ten (PTEN).

CONCLUSIONS

Decreased oxidation of cortisol and defects of insulin signaling in endometrium were observed in PCOS with IR patients. The excessive cortisol level, derived from the reduction of 11β-HSD2, might contribute to the development of endometrial IR by inhibiting the insulin signaling pathway via induction of PTEN expression in EECs.

FGF21 regulates insulin sensitivity following long-term chronic stress

Objective

Post-traumatic stress disorder (PTSD) increases type 2 diabetes risk, yet the underlying mechanisms are unclear. We investigated how early-life exposure to chronic stress affects long-term insulin sensitivity.

Methods

C57Bl/6J mice were exposed to chronic variable stress for 15 days (Cvs) and then recovered for three months without stress (Cvs3m).

Results

Cvs mice showed markedly increased plasma corticosterone and hepatic insulin resistance. Cvs3m mice exhibited improved whole-body insulin sensitivity along with enhanced adipose glucose uptake and skeletal muscle mitochondrial function and fatty acid oxidation. Plasma FGF21 levels were substantially increased and associated with expression of genes involved in fatty acid oxidation and formation of brown-like adipocytes. In humans, serum FGF21 levels were associated with stress coping long time after the exposure.

Conclusions

Early-life exposure to chronic stress leads to long term improvements in insulin sensitivity, oxidative metabolism and adipose tissue remodeling. FGF21 contributes to a physiological memory mechanism to maintain metabolic homeostasis.

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Early-life exposure of mice to stress (CVS) causes acute insulin resistance but improves long-term insulin sensitivity.

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3 months after stress, mice had enhanced adipose glucose uptake and higher skeletal muscle mitochondrial function.

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Plasma FGF21 and gene expression for formation of brown-like adipocytes were substantially increased long after stress.

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In humans, serum FGF21 levels were associated with the ability to cope with stress long time after the exposure.

MicroRNA-190b regulates lipid metabolism and insulin sensitivity by targeting IGF-1 and ADAMTS9 in non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is characterized by ectopic lipid accumulation and insulin resistance, yet the underlying molecular mechanisms are poorly understood. MiR-190b is thought to play a role in hepatocellular carcinoma by modulating insulin resistance; however, its role in NAFLD remains unknown. Here, we found that miR-190b expression was significantly increased in the liver tissues of patients with NAFLD, compared to normal tissues. Moreover, miR-190b was upregulated in a high-fat diet NAFLD mouse model and a free fatty acid-induced NAFLD cellular model. Knockdown of miR-190b decreased aspartate transaminase (AST), alanine transaminase (ALT), triglyceride (TG), and total cholesterol (TC). It also reduced expression of the lipogenic genes fatty acid synthase (FAS) and 3-hydroxy-3-methylglutarylCoA reductase (HMGCR), alleviated hepatic steatosis, improved glucose tolerance, elevated insulin sensitivity, and activated insulin receptor substrate (IRS)2/Akt signaling in vivo and/or in vitro. Furthermore, we confirmed that miR-190b directly targeted IGF-1 and ADAMTS9. MiR-190b overexpression suppressed expression of IGF-1 and ADAMTS9, which were increased by miR-190b inhibition. Expression of IGF-1 and ADAMTS9 was inversely correlated with miR-190b in liver tissues of patients with NAFLD, respectively. We also found that IGF-1 or ADAMTS9 inhibition partially reversed the effects of miR-190b on lipid metabolism and insulin signaling in vitro. Taken together, the data reveal that miR-190b inhibition suppressed lipid accumulation and improved insulin sensitivity by targeting IGF-1 and ADAMTS9, suggesting that miR-190b inhibition may be a therapeutic strategy against NAFLD.

Clinical Practice Guideline: Hoarseness (Dysphonia) (Update)

Objective

This guideline provides evidence-based recommendations on treating patients who present with dysphonia, which is characterized by altered vocal quality, pitch, loudness, or vocal effort that impairs communication and/or quality of life. Dysphonia affects nearly one-third of the population at some point in its life. This guideline applies to all age groups evaluated in a setting where dysphonia would be identified or managed. It is intended for all clinicians who are likely to diagnose and treat patients with dysphonia.

Purpose

The primary purpose of this guideline is to improve the quality of care for patients with dysphonia, based on current best evidence. Expert consensus to fill evidence gaps, when used, is explicitly stated and supported with a detailed evidence profile for transparency. Specific objectives of the guideline are to reduce inappropriate variations in care, produce optimal health outcomes, and minimize harm. For this guideline update, the American Academy of Otolaryngology—Head and Neck Surgery Foundation selected a panel representing the fields of advanced practice nursing, bronchoesophagology, consumer advocacy, family medicine, geriatric medicine, internal medicine, laryngology, neurology, otolaryngology–head and neck surgery, pediatrics, professional voice, pulmonology, and speech-language pathology.

Action Statements

The guideline update group made strong recommendations for the following key action statements (KASs): (1) Clinicians should assess the patient with dysphonia by history and physical examination to identify factors where expedited laryngeal evaluation is indicated. These include, but are not limited to, recent surgical procedures involving the head, neck, or chest; recent endotracheal intubation; presence of concomitant neck mass; respiratory distress or stridor; history of tobacco abuse; and whether the patient is a professional voice user. (2) Clinicians should advocate voice therapy for patients with dysphonia from a cause amenable to voice therapy. The guideline update group made recommendations for the following KASs: (1) Clinicians should identify dysphonia in a patient with altered voice quality, pitch, loudness, or vocal effort that impairs communication or reduces quality of life (QOL). (2) Clinicians should assess the patient with dysphonia by history and physical examination for underlying causes of dysphonia and factors that modify management. (3) Clinicians should perform laryngoscopy, or refer to a clinician who can perform laryngoscopy, when dysphonia fails to resolve or improve within 4 weeks or irrespective of duration if a serious underlying cause is suspected. (4) Clinicians should perform diagnostic laryngoscopy, or refer to a clinician who can perform diagnostic laryngoscopy, before prescribing voice therapy and document/communicate the results to the speech-language pathologist (SLP). (5) Clinicians should advocate for surgery as a therapeutic option for patients with dysphonia with conditions amenable to surgical intervention, such as suspected malignancy, symptomatic benign vocal fold lesions that do not respond to conservative management, or glottic insufficiency. (6) Clinicians should offer, or refer to a clinician who can offer, botulinum toxin injections for the treatment of dysphonia caused by spasmodic dysphonia and other types of laryngeal dystonia. (7) Clinicians should inform patients with dysphonia about control/preventive measures. (8) Clinicians should document resolution, improvement or worsened symptoms of dysphonia, or change in QOL of patients with dysphonia after treatment or observation. The guideline update group made a strong recommendation against 1 action: (1) Clinicians should not routinely prescribe antibiotics to treat dysphonia. The guideline update group made recommendations against other actions: (1) Clinicians should not obtain computed tomography (CT) or magnetic resonance imaging (MRI) for patients with a primary voice complaint prior to visualization of the larynx. (2) Clinicians should not prescribe antireflux medications to treat isolated dysphonia, based on symptoms alone attributed to suspected gastroesophageal reflux disease (GERD) or laryngopharyngeal reflux (LPR), without visualization of the larynx. (3) Clinicians should not routinely prescribe corticosteroids for patients with dysphonia prior to visualization of the larynx. The policy level for the following recommendation about laryngoscopy at any time was an option: (1) Clinicians may perform diagnostic laryngoscopy at any time in a patient with dysphonia.

Disclaimer

This clinical practice guideline is not intended as an exhaustive source of guidance for managing dysphonia (hoarseness). Rather, it is designed to assist clinicians by providing an evidence-based framework for decision-making strategies. The guideline is not intended to replace clinical judgment or establish a protocol for all individuals with this condition, and it may not provide the only appropriate approach to diagnosing and managing this problem. Differences from Prior Guideline (1) Incorporation of new evidence profiles to include the role of patient preferences, confidence in the evidence, differences of opinion, quality improvement opportunities, and any exclusion to which the action statement does not apply (2) Inclusion of 3 new guidelines, 16 new systematic reviews, and 4 new randomized controlled trials (3) Inclusion of a consumer advocate on the guideline update group (4) Changes to 9 KASs from the original guideline (5) New KAS 3 (escalation of care) and KAS 13 (outcomes) (6) Addition of an algorithm outlining KASs for patients with dysphonia

Chronic hyperinsulinemia induced miR-27b is linked to adipocyte insulin resistance by targeting insulin receptor

Defect in insulin signaling leads to the development of insulin resistance followed by type 2 diabetes. Exploiting our previously developed physiological chronic hyperinsulinemia (CI)-mediated insulin resistance (IR) model, we wanted to understand how miRNAs contribute to the development of IR. Amongst the identified and validate miRNAs, the expression of miR-27b was found to be highly upregulated during CI-induced IR in 3T3-L1 adipocytes. We also validated the expression of miR-27b in CI-induced IR in human mesenchymal stem cell (hMSC)-derived adipocytes and in vivo high fat diet (HFD)-induced IR mice model. Bioinformatics target prediction softwares and luciferase reporter assay identified insulin receptor (INSR) as one of a prime target of miR-27b. Lentiviral mediated overexpression of miR-27b impairs insulin signaling by modulating INSR expression that in turn led to decreased glucose uptake in both 3T3-L1 and hMSC-derived adipocytes. Conversely, inhibition of miR-27b reversed CI-mediated suppression of target protein INSR and improved phosphorylation of Akt, a nodal protein of insulin signaling that is impaired by CI treatment. Lentiviral mediated overexpression of miR-27b in in vivo C57BL/6 mice impaired whole body glucose tolerance and adipose tissue insulin sensitivity. Furthermore, inhibition of miR-27b in HFD-induced insulin resistance mice model improved glucose tolerance and adipose tissue insulin sensitivity by increasing the expression of its target gene INSR in eWAT. Thus, our results indicate that miR-27b functions as a prime modulator of CI-induced IR via regulating the expression of INSR. KEY MESSAGES: miR-27b is upregulated in different in vitro and in vivo models of insulin resistance. miR-27b directly suppresses the expression of INSR by targeting 3'UTR of INSR. Modulation of miR-27b expression regulates insulin sensitivity by targeting INSR.

The prevalence and etiology of extreme hypertriglyceridemia in children: Data from a tertiary children's hospital

BACKGROUND

Extreme hypertriglyceridemia (eHTG; serum triglycerides ≥ 2000 mg/dL) poses a significant risk for acute pancreatitis. There is paucity of data regarding the prevalence and etiology of eHTG in children.

OBJECTIVE

To determine the prevalence, clinical features and etiologies of patients with eHTG at a tertiary children's hospital in the United States and in the United States National Health and Nutrition Examination Survey (NHANES).

METHODS

A retrospective analysis was conducted of the electronic medical records of the Children's Medical Center, Dallas, from 2000-2015, and the NHANES data from 2005-2014 for eHTG.

RESULTS

Of 30,623 children, 36 (∼ 1 in 1000) had eHTG and one-third of them developed acute pancreatitis. They tended to be female (61%), Hispanic (39%), and nonobese (median body mass index z-score 1.60 and 1.25 in males and females, respectively). Most patients had secondary causes such as uncontrolled diabetes mellitus (30%), L-asparaginase and high-dose corticosteroid therapy for acute lymphoblastic leukemia (28%), and sirolimus/tacrolimus therapy after solid organ transplantation (14%). Five patients (14%) had type 1 hyperlipoproteinemia (T1HLP; familial chylomicronemia syndrome). The NHANES data revealed that none of the 2362 children had eHTG, and the prevalence in adults was 0.02%.

CONCLUSIONS

Extreme HTG is rare in children and majority of the children had secondary causes. Patients with diabetes mellitus or receiving drugs, such as, L-asparaginase, corticosteroids, and sirolimus, should be closely monitored for eHTG. Prevalence of T1HLP is approximately 1 in 6000 at a tertiary care center with an estimated population prevalence of 1 in 3,00,000. Early neonatal screening and intervention for T1HLP can prevent life-threatening morbidities such as acute pancreatitis.

The effects of hydroalcoholic extract of Allium elburzense Wendelbo bulb on dexamethasone-induced dyslipidemia, hyperglycemia, and oxidative stress in rats

Recent evidences have suggested the beneficial cardiovascular effects of some plants belonging to the genus Allium. The present study is an attempt to investigate the effects of hydroalcoholic extract of Allium elburzense bulb on dexamethasone-induced dyslipidemia in rats. Total phenolic content of A. elburzense bulb hydroalcoholic extract was determined using Folin-Ciocalteu method. Thirty-six male Wistar albino rats in 6 groups were studied. Group 1 (dyslipidemic control) received dexamethasone (10 mg/kg/day, s.c.) for 7 days, groups 2-4 (treated) received dexamethasone and simultaneously treated orally with 100, 200, or 400 mg/kg of A. elburzense extract, group 5 (normal control) received a single daily injection of normal saline (1 mL/kg, s.c.) and the vehicle orally, and group 6 (reference) received dexamethasone and atorvastatin (40 mg/kg) orally. At the end of experiment, blood glucose, lipid profile, and malondialdehyde (MDA) levels were assessed in serum samples. Livers were processed for histopathological examination. Total phenolic content of A. elburzense extract was estimated to be 33.52 ± 1.3% mg gallic acid equivalent/g of the dried plant extract. The plant extract significantly reduced serum blood glucose, triglyceride, total cholesterol, low-density lipoprotein-cholesterol, and MDA levels and increased the high density lipoprotein-cholesterol level and also improved liver steatosis compared to the dyslipidemic control group. These results suggest the hydroalcoholic extract of A. elburzense bulb has anti-dyslipidemic, anti-hyperglycemic, and antioxidant effects on rats receiving high doses of dexamethasone.

Telmisartan is effective to ameliorate metabolic syndrome in rat model - a preclinical report

BACKGROUND

Metabolic syndrome (MS) is known to be associated with hypertension, insulin resistance, and dyslipidemia, and it raises the risk for cardiovascular diseases and diabetes mellitus. Telmisartan is used in clinic as an angiotensin II receptor blocker and it is also identified as activating peroxisome proliferator-activated receptors δ (PPARδ). Activation of PPARδ produced beneficial effects on fatty acid metabolism and glucose metabolism. This study aims to investigate the effects of telmisartan on the modulation of MS in rats fed a high-fat/high-sodium diet.

METHODS

Rats were fed with a high-fat/high-sodium diet and received injections of streptozotocin at low dose to induce MS. Then, rats with MS were treated with telmisartan. The weight, glucose tolerance, and insulin sensitivity were measured. The lipid profiles were also obtained. The weights of retroperitoneal and epididymal fat pads were determined. The role of PPARδ in telmisartan treatment was identified in rats pretreated with the specific antagonist GSK0660.

RESULTS

The results showed that telmisartan, but not losartan, significantly reduced plasma glucose and plasma insulin, and improved insulin resistance in rats with MS. Telmisartan also decreased blood pressure and lipids more significantly than losartan. Moreover, GSK0660 effectively reversed the effects of telmisartan in the MS rats. In the MS group, telmisartan activated PPARδ to enhance the levels of phosphorylated GLUT4 in muscle or the expression of phosphoenolpyruvate carboxykinase (PEPCK) in the liver, which was also abolished by GSK0660. Telmisartan is useful to ameliorate hypertension and insulin resistance in rats with MS. Telmisartan improves the insulin resistance through increased expression of GLUT4 and down-regulation of PEPCK via PPARδ-dependent mechanisms.

CONCLUSION

Telmisartan has been proven to ameliorate MS, particularly in the prediabetes state. Therefore, telmisartan is suitable to develop for the management of MS in clinics.

Insulin Resistance, Prediabetes, Metabolic Syndrome: What Should Every Pediatrician Know?

The Metabolic syndrome describes a clustering of typical cardiovascular risk factors. The syndrome is also known as "Insulin Resistance syndrome" as a substantial part of the pathophysiology is driven by resistance to the metabolic effects of insulin. The major cause of insulin resistance in childhood is a typical lipid partitioning pattern characterized by increased deposition of lipids within insulin responsive tissues, such as the liver and skeletal muscle and within the viscera. This lipid deposition pattern is also associated with infiltration of intra-abdominal tissues with cells of the immune system, inducing systemic, low-grade inflammation typically observed in insulin resistant obese children and adolescents. Several clues derived from a careful history and physical examination, along with a basic laboratory workup, provide clues in regards to risk stratification in obese children.

Insulin resistance enhances the mitogen-activated protein kinase signaling pathway in ovarian granulosa cells

The ovary is the main regulator of female fertility. Granulosa cell dysfunction may be involved in various reproductive endocrine disorders. Here we investigated the effect of insulin resistance on the metabolism and function of ovarian granulosa cells, and dissected the functional status of the mitogen-activated protein kinase signaling pathway in these cells. Our data showed that dexamethasone-induced insulin resistance in mouse granulosa cells reduced insulin sensitivity, accompanied with an increase in phosphorylation of p44/42 mitogen-activated protein kinase. Furthermore, up-regulation of cytochrome P450 subfamily 17 and testosterone and down-regulation of progesterone were observed in insulin-resistant mouse granulosa cells. Inhibition of p44/42 mitogen-activated protein kinase after induction of insulin resistance in mouse granulosa cells decreased phosphorylation of p44/42 mitogen-activated protein kinase, downregulated cytochrome P450 subfamily 17 and lowered progesterone production. This insulin resistance cell model can successfully demonstrate certain mechanisms such as hyperandrogenism, which may inspire a new strategy for treating reproductive endocrine disorders by regulating cell signaling pathways.

Molecular Integration of Incretin and Glucocorticoid Action Reverses Immunometabolic Dysfunction and Obesity

Chronic inflammation has been proposed to contribute to the pathogenesis of diet-induced obesity. However, scarce therapeutic options are available to treat obesity and the associated immunometabolic complications. Glucocorticoids are routinely employed for the management of inflammatory diseases, but their pleiotropic nature leads to detrimental metabolic side effects. We developed a glucagon-like peptide-1 (GLP-1)-dexamethasone co-agonist in which GLP-1 selectively delivers dexamethasone to GLP-1 receptor-expressing cells. GLP-1-dexamethasone lowers body weight up to 25% in obese mice by targeting the hypothalamic control of feeding and by increasing energy expenditure. This strategy reverses hypothalamic and systemic inflammation while improving glucose tolerance and insulin sensitivity. The selective preference for GLP-1 receptor bypasses deleterious effects of dexamethasone on glucose handling, bone integrity, and hypothalamus-pituitary-adrenal axis activity. Thus, GLP-1-directed glucocorticoid pharmacology represents a safe and efficacious therapy option for diet-induced immunometabolic derangements and the resulting obesity.

Systemic Effects of Repeated Intraocular Dexamethasone Intravitreal Implant in Diabetic Patients: A Retrospective Study

INTRODUCTION

The objective of this study is to evaluate the influence of repeated intraocular dexamethasone implant (Ozurdex) injections on metabolic control in type 2 diabetic patients.

METHODS

Retrospective study of 165 type 2 diabetic patients starting Ozurdex treatment who received no less than three consecutive injections. Glycated hemoglobin (HbA1c), serum creatinine, total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides (TGs) were evaluated during 15 months of follow-up after Ozurdex treatment onset.

RESULTS

Fifty-seven patients met inclusion criteria. Mean baseline values for HbA1c, creatinine, total cholesterol, HDL cholesterol, and TGs before treatment (7.1%, 1.3, 176.7, 51.1, and 125.6 mg/dl, respectively) were similar to mean values after Ozurdex onset (Wilcoxon test p values were 0.68, 0.41, 0.06, 0.87, and 0.33, respectively) and remained stable during the follow-up period. Mean LDL cholesterol levels increased slightly after Ozurdex treatment onset (90.1 vs 88.2 mg/dl, p = 0.04) but after 15 months of follow-up they had returned to baseline values. Transient increase in LDL cholesterol was remarkable in the group of 24 bilaterally treated patients (96.8 vs 88.4 mg/dl, p = 0.03). A third of these patients increased their baseline LDL values by more than 20%. Even with continuous injections of Ozurdex, LDL cholesterol levels also declined back to baseline by month 15.

CONCLUSION

Ozurdex injections had no influence on HbA1c or renal function. Lipid profile changes were mild and transient. However, a significant temporary increase has been found in LDL cholesterol levels in patients receiving simultaneous bilateral injections. Lipid levels should be monitored in patients starting with bilateral Ozurdex injections especially in those with recent history of acute myocardial infarction.

Comparison of Pioglitazone and Metformin Efficacy against Glucocorticoid Induced Atherosclerosis and Hepatic Steatosis in Insulin Resistant Rats

INTRODUCTION

Insulin Resistance is a major cause of Atherosclerosis (AS) and Non Alcoholic Fatty Liver Disease (NAFLD). These lipid alterations in blood vessels and liver may progress to cardiovascular abnormalities and cirrhosis respectively. Drugs like pioglitazone (PIO) and metformin (MET) are effective insulin sensitizers used in T2DM. But their efficacy and tolerability needs to be compared in IR associated abnormalities.

AIM

To compare the efficacy of PIO and MET in glucocorticoid induced AS, Hepatic Steatosis (HS) and IR in albino rats.

MATERIALS AND METHODS

Male Wistar albino rats were randomized into four groups (n=6). Group 1 (Normal control) rats consumed 2% gum acacia orally for 12 days. Group 2 {dexamethasone (DEX) control} rats were administered 2% gum acacia orally for 12 days and DEX (8 mg/kg) intraperitoneally (i.p.) from 7th to 12th day during the study period. Group 3 and 4 (PIO and MET control) rats received oral administration of PIO (45 mg/kg) and MET (1000 mg/kg) for 12 days respectively. Both groups were treated with DEX (8 mg/kg/i.p.) from 7th to 12th day during the study period. On last day, fasting blood was collected and rats were sacrificed by cervical dislocation; aorta and liver tissues were isolated for the histopathological examination. Body weight, liver weight and liver volume were measured. Blood samples were processed for biochemical parameters. The data were analysed by One-way Analysis of variance (ANOVA) followed by Scheffe's multiple comparison post-hoc test. The statistical significance was assumed at p<0.05.

RESULTS

Our results established the possible role of DEX in the development of AS and HS. Histopathological examination of Group 2 rats treated with DEX showed a marked lipid accumulation in the aorta and liver. Administration of MET and PIO resulted in partial to complete restoration of DEX induced fatty changes in aorta and liver. Both drugs significantly (p<0.05) prevented the elevation of insulin, lipid, glucose levels, liver weight and liver volume in DEX treated rats. They had significantly (p<0.05) improved body weight and insulin sensitivity. However, PIO was highly significant (p<0.05) compared to MET in reducing DEX induced IR complications.

CONCLUSION

These findings suggest that PIO was more effective insulin sensitizer compared to MET in reducing AS, HS and IR induced by glucocorticoids.

Impact of Adrenal Steroids on Regulation of Adipose Tissue

Corticosteroids are secreted by the adrenal glands and control the functions of adipose tissue via the activation of mineralocorticoid receptor (MR) and glucocorticoid receptor (GR). In turn, adipocytes release a large variety of adipokines into the bloodstream, regulating the function of several organs and tissues, including the adrenal glands, hereby controlling corticosteroid production. In adipose tissue, the activation of the MR by glucocorticoids (GC) and aldosterone affects important processes such as adipocyte differentiation, oxidative stress, autophagic flux, adipokine expression as well as local production of GC through upregulation of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Notably, the proinflammatory responses induced by the MR are counteracted by activation of the GR, whose activity inhibits the expression of inflammatory adipokines. Both GR and MR are deeply involved in adipogenesis and adipose expansion; hence pharmacological blockade of these two receptors has proven effective against adipose tissue dysfunction in experimental models of obesity and metabolic syndrome (MetS), suggesting a potential use for MR and GR antagonists in these clinical settings. Importantly, obesity and Cushing's syndrome (CS) share metabolic similarities and are characterized by high levels of circulating corticosteroids, which in turn are able to deeply affect adipose tissue. In addition, pharmacological approaches aimed at reducing aldosterone and GC levels, by means of the inhibition of CYP11B2 (aldosterone synthase) or 11β-HSD1, represent alternative strategies to counter the detrimental effects of excessive levels of corticosteroids, which are often observed in obesity and, more general, in MetS. © 2017 American Physiological Society. Compr Physiol 7:1425-1447, 2017.

Curcumin limits weight gain, adipose tissue growth, and glucose intolerance following the cessation of exercise and caloric restriction in rats

Weight regain, adipose tissue growth, and insulin resistance can occur within days after the cessation of regular dieting and exercise. This phenomenon has been attributed, in part, to the actions of stress hormones as well as local and systemic inflammation. We investigated the effect of curcumin, a naturally occurring polyphenol known for its anti-inflammatory properties and inhibitory action on 11β-HSD1 activity, on preserving metabolic health and limiting adipose tissue growth following the cessation of daily exercise and caloric restriction (CR). Sprague-Dawley rats (6-7 wk old) underwent a "training" protocol of 24-h voluntary running wheel access and CR (15-20 g/day; ~50-65% of ad libitum intake) for 3 wk ("All Trained") or were sedentary and fed ad libitum ("Sed"). After 3 wk, All Trained were randomly divided into one group which was terminated immediately ("Trained"), and two detrained groups which had their wheels locked and were reintroduced to ad libitum feeding for 1 wk. The wheel locked groups received either a daily gavage of a placebo ("Detrained + Placebo") or curcumin (200 mg/kg) ("Detrained + Curcumin"). Cessation of daily CR and exercise caused an increase in body mass, as well as a 9- to 14-fold increase in epididymal, perirenal, and inguinal adipose tissue mass, all of which were attenuated by curcumin ( P < 0.05). Insulin area under the curve (AUC) during an oral glucose tolerance test, HOMA-IR, and C-reactive protein (CRP) were elevated 6-, 9-, and 2-fold, respectively, in the Detrained + Placebo group vs. the Trained group (all P < 0.05). Curcumin reduced insulin AUC, HOMA-IR, and CRP vs. the placebo group (all P < 0.05). Our results indicate that curcumin has a protective effect against weight regain and impaired metabolic control following a successful period of weight loss through diet and exercise, perhaps via inhibition of glucocorticoid action and inflammation. NEW & NOTEWORTHY Weight regain after dieting and exercise is a common phenomenon plaguing many individuals. The biological mechanisms underlying weight regain are incompletely understood and are likely multifactorial. In this paper, we examined the metabolic implications of curcumin, a compound known for its anti-inflammatory properties and inhibitory action on the enzyme 11β-HSD1, in a rodent model of adiposity rebound after the cessation of diet and exercise.

High-fat diet effects on metabolic responses to chronic stress

CONTEXT

High-fat diets and chronic stress are prevalent risk factors for various chronic diseases in modern societies.

OBJECTIVE

This study investigated the effect of high-fat diet on glucose-related metabolic responses to chronic foot-shock stress.

MATERIALS AND METHODS

Male rats were divided into high-fat diet (containing 54.21% saturated and 44.89% unsaturated fatty acids) and normal diet groups and then into stress and non-stress subgroups. The diets were applied for 5 weeks, and stress was induced during the last week of the diet course. Plasma levels of metabolic parameters, HOMA-IR index, intra-abdominal fat weight, and islets' insulin secretion were assessed.

RESULTS

High-fat diet increased abdominal fat weight and plasma leptin, and insulin levels in response to stress without affecting HOMA-IR index and islets' insulin secretion.

CONCLUSIONS

High proportion of unsaturated fat may not lead to deleterious metabolic responses; however combined with chronic stress has a synergistic and adverse effect on visceral adiposity and results in elevated plasma leptin.

Glucose Metabolism Abnormalities in Cushing Syndrome: From Molecular Basis to Clinical Management

An impaired glucose metabolism, which often leads to the onset of diabetes mellitus (DM), is a common complication of chronic exposure to exogenous and endogenous glucocorticoid (GC) excess and plays an important part in contributing to morbidity and mortality in patients with Cushing syndrome (CS). This article reviews the pathogenesis, epidemiology, diagnosis, and management of changes in glucose metabolism associated with hypercortisolism, addressing both the pathophysiological aspects and the clinical and therapeutic implications. Chronic hypercortisolism may have pleiotropic effects on all major peripheral tissues governing glucose homeostasis. Adding further complexity, both genomic and nongenomic mechanisms are directly induced by GCs in a context-specific and cell-/organ-dependent manner. In this paper, the discussion focuses on established and potential pathologic molecular mechanisms that are induced by chronically excessive circulating levels of GCs and affect glucose homeostasis in various tissues. The management of patients with CS and DM includes treating their hyperglycemia and correcting their GC excess. The effects on glycemic control of various medical therapies for CS are reviewed in this paper. The association between DM and subclinical CS and the role of screening for CS in diabetic patients are also discussed.

Glucocorticoid-Induced Diabetes Mellitus: An Important but Overlooked Problem

Glucocorticoids are widely used as potent anti-inflammatory and immunosuppressive drugs to treat a wide range of diseases. However, they are also associated with a number of side effects, including new-onset hyperglycemia in patients without a history of diabetes mellitus (DM) or severely uncontrolled hyperglycemia in patients with known DM. Glucocorticoid-induced diabetes mellitus (GIDM) is a common and potentially harmful problem in clinical practice, affecting almost all medical specialties, but is often difficult to detect in clinical settings. However, scientific evidence is lacking regarding the effects of GIDM, as well as strategies for prevention and treatment. Similarly to nonsteroid-related DM, the principles of early detection and risk factor modification apply. Screening for GIDM should be considered in all patients treated with medium to high doses of glucocorticoids. Challenges in the management of GIDM stem from wide fluctuations in postprandial hyperglycemia and the lack of clearly defined treatment protocols. Together with lifestyle measures, hypoglycemic drugs with insulin-sensitizing effects are indicated. However, insulin therapy is often unavoidable, to the point that insulin can be considered the drug of choice. The treatment of GIDM should take into account the degree and pattern of hyperglycemia, as well as the type, dose, and schedule of glucocorticoid used. Moreover, it is essential to instruct the patient and/or the patient's family about how to perform the necessary adjustments. Prospective studies are needed to answer the remaining questions regarding GIDM.

Adipose stem cells from obese patients show specific differences in the metabolic regulators vitamin D and Gas5

Adipose tissue is a significant source of mesenchymal stem cells for regenerative therapies; however, caution should be taken as their environmental niche can affect their functional properties. We have previously demonstrated the negative impact of obesity on the function of adipose-derived stem cells (ASCs). Here we have evaluated other possible properties and targets that are altered by obesity such as the recently described long non-coding molecule Gas5, which is involved in glucocorticoid resistance. Using ASCs isolated from obese (oASCs) and control subjects (cASCs), we have analyzed additional metabolic and inflammatory conditions that could be related with their impaired therapeutic potential and consequently their possible usefulness in the clinic.

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Altered genetic and metabolic targets by obesity in adipose stem cells population

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Gas5 involved in glucocorticoid resistance such as altered target

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Additional metabolic and inflammation conditions on obese adipose stem cells

Reduced water intake deteriorates glucose regulation in patients with type 2 diabetes

Epidemiological research has demonstrated that low daily total water intake is associated with increased diagnosis of hyperglycemia. Possible mechanisms for this increase include hormones related to the hypothalamic pituitary axis as well as the renin-angiotensin-aldosterone system (RAAS). Therefore, the hypothesis of the present study was that acute low water intake would result in differential hormonal profiles and thus impaired blood glucose regulation during an oral glucose tolerance test (OGTT) in people with type 2 diabetes mellitus (T2DM). Nine men (53 ± 9 years, 30.0 ± 4.3 m∙kg^-2, 32% ± 6% body fat) diagnosed with T2DM completed OGTTs in euhydrated (EUH) and hypohydrated (HYP) states in counterbalanced order. Water restriction led to hypohydration of -1.6% of body weight, with elevated plasma (EUH: 288 ± 4, HYP: 298 ± 6 mOsm·kg^-1; P < .05) and urine (EUH: 512 ± 185, HYP: 994 ± 415 mOsm·kg^-1; P < .05) osmolality. There was a significant main effect of condition for serum glucose (at time 0 minute 9.5 ± 4.2 vs 10.4 ± 4.4 mmol∙L^-1 and at time 120 minutes 19.1 ± 4.8 vs 21.0 ± 4.1 mmol∙L^-1 for EUH and HYP, respectively; P < .001) but not insulin (mean difference between EUH and HYP -12.1 ± 44.9 pmol∙L^-1, P = .390). An interaction between time and condition was observed for cortisol: decrease from minute 0 to 120 in EUH (-85.3 ± 82.1 nmol∙L^-1) vs HYP (-25.0 ± 43.0 nmol∙L^-1; P = .017). No differences between conditions were found within RAAS-related hormones. Therefore, we can conclude that 3 days of low total water intake in people with T2DM acutely impairs blood glucose response during an OGTT via cortisol but not RAAS-mediated glucose regulation.

The effects of aging in the hippocampus and cognitive decline

Aging is a natural process that is associated with cognitive decline as well as functional and social impairments. One structure of particular interest when considering aging and cognitive decline is the hippocampus, a brain region known to play an important role in learning and memory consolidation as well as in affective behaviours and mood regulation, and where both functional and structural plasticity (e.g., neurogenesis) occur well into adulthood. Neurobiological alterations seen in the aging hippocampus including increased oxidative stress and neuroinflammation, altered intracellular signalling and gene expression, as well as reduced neurogenesis and synaptic plasticity, are thought to be associated with age-related cognitive decline. Non-invasive strategies such as caloric restriction, physical exercise, and environmental enrichment have been shown to counteract many of the age-induced alterations in hippocampal signalling, structure, and function. Thus, such approaches may have therapeutic value in counteracting the deleterious effects of aging and protecting the brain against age-associated neurodegenerative processes.