Acute hypercortisolemia exerts depot-specific effects on abdominal and femoral adipose tissue function

Context Glucocorticoids have pleiotropic metabolic functions and acute glucocorticoid excess affects fatty acid metabolism, increasing systemic lipolysis. Whether glucocorticoids exert adipose tissue depot-specific effects remains unclear. Objective In vivo assessment of femoral and abdominal adipose tissue responses to acute glucocorticoid administration. Design and outcome measures Nine healthy male volunteers studied on two occasions, following a hydrocortisone infusion (0.2 mg.kg-1.min-1 for 14 hours) and saline, respectively, given in randomized double-blind order. Subjects were studied in the fasting state and following a 75g glucose drink with in vivo assessment of femoral adipose tissue blood flow (ATBF) using radioactive Xenon washout, and lipolysis and glucose uptake using the arterio-venous difference technique. In a separate study (same infusion design), 8 further healthy male subjects underwent assessment of fasting abdominal ATBF and lipolysis only. Lipolysis was assessed as the net release of non-esterified fatty acids (NEFA) from femoral and abdominal subcutaneous adipose tissue. Results Acute hypercortisolemia significantly increased basal and postprandial ATBF in femoral adipose tissue, but femoral net NEFA release did not change. In abdominal adipose tissue, hypercortisolemia induced significant increases in basal ATBF and NEFA release. Conclusions Acute hypercortisolemia induces differential lipolysis and ATBF responses in abdominal and femoral adipose tissue, suggesting depot-specific glucocorticoid effects. Abdominal, but not femoral, adipose tissue contributes to the hypercortisolemia-induced systemic NEFA increase, with likely contributions from other adipose tissue sources and intravascular triglyceride hydrolysis

Differential adipose tissue gene expression profiles in abacavir treated patients that may contribute to the understanding of cardiovascular risk: a microarray study

OBJECTIVE:To compare changes in gene expression by microarray from subcutaneous adipose tissue from HIV treatment naïve patients treated with efavirenz based regimens containing abacavir (ABC), tenofovir (TDF) or zidovidine (AZT). DESIGN:Subcutaneous fat biopsies were obtained before, at 6- and 18-24-months after treatment, and from HIV negative controls. Groups were age, ethnicity, weight, biochemical profile, and pre-treatment CD4 count matched. Microarray data was generated using the Agilent Whole Human Genome Microarray. Identification of differentially expressed genes and genomic response pathways was performed using limma and gene set enrichment analysis. RESULTS:There were significant divergences between ABC and the other two groups 6 months after treatment in genes controlling cell adhesion and environmental information processing, with some convergence at 18-24 months. Compared to controls the ABC group, but not AZT or TDF showed enrichment of genes controlling adherence junction, at 6 months and 18-24 months (adjusted p<0.05) and focal adhesions and tight junction at 6 months (p<0.5). Genes controlling leukocyte transendothelial migration (p<0.05) and ECM-receptor interactions (p = 0.04) were over-expressed in ABC compared to TDF and AZT at 6 months but not at 18-24 months. Enrichment of pathways and individual genes controlling cell adhesion and environmental information processing were specifically dysregulated in the ABC group in comparison with other treatments. There was little difference between AZT and TDF. CONCLUSION:After initiating treatment, there is divergence in the expression of genes controlling cell adhesion and environmental information processing between ABC and both TDF and AZT in subcutaneous adipose tissue. If similar changes are also taking place in other tissues including the coronary vasculature they may contribute to the increased risk of cardiovascular events reported in patients recently started on abacavir-containing regimens

Adopting a Citizen Science Approach in Translational Experimental Medicine Research in Non-Alcoholic Fatty Liver Disease: A Study Protocol

Citizen science approaches are widely and successfully used in biological, environmental, and ecological sciences; however, they are rarely applied in other domains, such as translational health research, notably in the field of liver disease and metabolism. We have designed a study that aims to explore the application of the citizen science approach in a translational experimental medicine study on non-alcoholic fatty liver disease (NAFLD) and a 12-week lifestyle and weight loss program. In this methodological paper, we describe the process of involving citizen scientists in the study. We will recruit a convenience sample of 31 participants (with and without NAFLD) and a half-dozen citizen scientists (members of the public). Citizen scientists will work alongside clinical and non-clinical researchers in a translational experimental medicine study on NAFLD. Citizen scientists will be involved in the co-design and/or review of data collection tools (e.g., semi-structured open-ended questionnaire surveys and semi-structured wellbeing diaries completed by the participants), co-analysis of data on participants’ experiences and motivations, co-drafts of research findings and papers, and suggestions for policy recommendations. Citizen scientists will be trained in the research tasks they will undertake, and will be either co-authors or their names will be mentioned in the acknowledgements in research paper(s) based on the level of research contributions. Lessons learned from implementing citizen science in this study will help to reveal the advantages, limitations, and implications of involving citizen scientists in the translational medicine research. Knowing citizen scientists’ motivations, expectations, training needs, and overall experience of involvement in this study could provide insights, which could inform the planning and conduct of future translational research studies. Involving citizen scientists in translational medicine research is an important step in extending research opportunities for members of the public; however, there may be methodological challenges, which may be identified and resolved by more research studies

Assessing treatment adherence is crucial to determine adequacy of mineralocorticoid therapy

Background: There is no consensus strategy for mineralocorticoid (MC) therapy titration in patients with primary adrenal insufficiency (PAI). W e aim to measure serum fludrocortisone (sFC) and urine fludrocortisone (uFC) levels and to determine their utility, alongside clinical/biochemical variables and treatment adherence to guide MC replacement dose titration. Methods: Multi-centre, observational, cross-sectional study on 41 patients with PAI on MC replacement therapy. sFC and uFC levels (measured by liquid chr omatography-tandem mass spectrometry), plasma renin concentration (PRC), electrolytes (Na+, K+), mean arterial blood pressure (MAP), total daily glucocorticoid (dGC) and MC (dMC) dose, and assessment of treatment adherence were incorporated into statis tical models. Results: We observed a close relationship between sFC and uFC ( r = 0.434, P = 0.005) and between sFC and the time from the last fludrocortisone dose ( r = −0.355, P = 0.023). Total dMC dose was related to dGC dose ( r = 0.556, P < 0.001), K+ (r = −0.388, P = 0.013) as well as sFC (r = 0.356, P = 0.022) and uFC (r = 0.531, P < 0.001). PRC was related to Na+ (r = 0.517, P < 0.001) and MAP (r = −0.427, P = 0.006), but not to MC dose, sFC or uFC. Regression analyses did not support a role for sFC, uFC or PRC measurements and confirmed K+ (B = −44.593, P = 0.005) as the most important variable to guide dMC titration. Of the patients, 32% were non-adherent with replacem ent therapy. When adherence was inserted into the regression model, it was the on ly factor affecting dMC. Conclusions: sFC and uFC levels are not helpful in guiding dMC titration. T reatment adherence impacts on clinical variables used to assess MC replacement and should be included as part of routine care in patients with PAI

Glucagon-like peptide 1 decreases lipotoxicity in non-alcoholic steatophepatitis

OBJECTIVE: Insulin resistance and lipotoxicity are pathognomonic in non-alcoholic steatohepatitis (NASH). Glucagon-like peptide-1 (GLP-1) analogues are licensed for type 2 diabetes, but no prospective experimental data exists in NASH. This study determined the effect of a long-acting GLP-1 analogue, liraglutide, on organ-specific insulin sensitivity, hepatic lipid handling and adipose dysfunction in biopsy-proven NASH.DESIGN: 14 patients were randomised to 1.8mg liraglutide or placebo for 12-weeks of the mechanistic component of a double-blind, randomized, placebo-controlled trial (ClinicalTrials.gov-NCT01237119). Patients underwent paired hyperinsulinaemic euglycaemic clamps, stable isotope tracers, adipose microdialysis and serum adipocytokine/metabolic profiling. In vitro isotope experiments on lipid flux were performed on primary human hepatocytes.RESULTS: Liraglutide reduced BMI (-1.9 vs. +0.04 kg/m2;p&lt;0.001), HbA1c (-0.3 vs. +0.3%;p&lt;0.01), cholesterol-LDL (-0.7 vs. +0.05 mmol/L;p&lt;0.01), ALT (-54 vs -4.0 IU/L;p&lt;0.01) and serum leptin, adiponectin, and CCL-2 (all p&lt;0.05). Liraglutide increased hepatic insulin sensitivity (-9.36 vs. -2.54% suppression of hepatic endogenous glucose production with low-dose insulin;p&lt;0.05). Liraglutide increased adipose tissue insulin sensitivity enhancing the ability of insulin to suppress lipolysis both globally (-24.9 vs. +54.8 pmol/L insulin required to ½ maximally suppress serum NEFA; p&lt;0.05), and specifically within subcutaneous adipose tissue (p&lt;0.05). In addition, liraglutide decreased hepatic DNL in-vivo (-1.26 vs. +1.30%; p&lt;0.05); a finding endorsed by the effect of GLP-1 receptor agonist on primary human hepatocytes (24.6% decrease in lipogenesis vs. untreated controls; p&lt;0.01).CONCLUSIONS: Liraglutide reduces metabolic dysfunction, insulin resistance and lipotoxicity in the key metabolic organs in the pathogenesis of NASH. Liraglutide may offer the potential for a disease-modifying intervention in NASH.</p

Glucagon-like peptide 1 decreases lipotoxicity in non-alcoholic steatophepatitis

Background & AimsInsulin resistance and lipotoxicity are pathognomonic in non-alcoholic steatohepatitis (NASH). Glucagon-like peptide-1 (GLP-1) analogues are licensed for type 2 diabetes, but no prospective experimental data exists in NASH. This study determined the effect of a long-acting GLP-1 analogue, liraglutide, on organ-specific insulin sensitivity, hepatic lipid handling and adipose dysfunction in biopsy-proven NASH.MethodsFourteen patients were randomised to 1.8mg liraglutide or placebo for 12-weeks of the mechanistic component of a double-blind, randomised, placebo-controlled trial (ClinicalTrials.gov-NCT01237119). Patients underwent paired hyperinsulinaemic euglycaemic clamps, stable isotope tracers, adipose microdialysis and serum adipocytokine/metabolic profiling. In vitro isotope experiments on lipid flux were performed on primary human hepatocytes.ResultsLiraglutide reduced BMI (−1.9 vs. +0.04kg/m2; p<0.001), HbA1c (−0.3 vs. +0.3%; p<0.01), cholesterol-LDL (−0.7 vs. +0.05mmol/L; p<0.01), ALT (−54 vs. −4.0IU/L; p<0.01) and serum leptin, adiponectin, and CCL-2 (all p<0.05). Liraglutide increased hepatic insulin sensitivity (−9.36 vs. −2.54% suppression of hepatic endogenous glucose production with low-dose insulin; p<0.05). Liraglutide increased adipose tissue insulin sensitivity enhancing the ability of insulin to suppress lipolysis both globally (−24.9 vs. +54.8pmol/L insulin required to ½ maximally suppress serum non-esterified fatty acids; p<0.05), and specifically within subcutaneous adipose tissue (p<0.05). In addition, liraglutide decreased hepatic de novo lipogenesis in vivo (−1.26 vs. +1.30%; p<0.05); a finding endorsed by the effect of GLP-1 receptor agonist on primary human hepatocytes (24.6% decrease in lipogenesis vs. untreated controls; p<0.01).ConclusionsLiraglutide reduces metabolic dysfunction, insulin resistance and lipotoxicity in the key metabolic organs in the pathogenesis of NASH. Liraglutide may offer the potential for a disease-modifying intervention in NASH

Characterisation of 11β-hydroxysteroid dehydrogenase 1 in human orbital adipose tissue: a comparison with subcutaneous and omental fat

Glucocorticoids (GCs) have a profound effect on adipose biology increasing tissue mass causing central obesity. The pre-receptor regulation of GCs by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) that activates cortisol from cortisone has been postulated as a fundamental mechanism underlying the metabolic syndrome mediating adipocyte hyperplasia and hypertrophy in the omental (OM) depot. Orbital adipose tissue (OF) is the site of intense inflammation and tissue remodelling in several orbital inflammatory disease states. In this study, we describe features of the GC metabolic pathways in normal human OF depot and compare it with subcutaneous (SC) and OM depots. Using an automated histological characterisation technique, OF adipocytes were found to be significantly smaller (parameters: area, maximum diameter and perimeter) than OM and SC adipocytes (P<0·001). Although immunohistochemical analyses demonstrated resident CD68+ cells in all three whole tissue adipose depots, OF CD68 mRNA and protein expression exceeded that of OM and SC (mRNA, P<0·05; protein, P<0·001). In addition, there was higher expression of glucocorticoid receptor (GR)α mRNA in the OF whole tissue depot (P<0·05). Conversely, 11β-HSD1 mRNA together with the markers of late adipocyte differentiation (FABP4 and G3PDH) were significantly lower in OF. Primary cultures of OF preadipocytes demonstrated predominant 11β-HSD1 oxo-reductase activity with minimal dehydrogenase activity. Orbital adipocytes are smaller, less differentiated, and express low levels of 11β-HSD1 but abundant GRα compared with SC and OM. OF harbours a large CD68+ population. These characteristics define an orbital microenvironment that has the potential to respond to sight-threatening orbital inflammatory disease

Nonclassic lipoid congenital adrenal hyperplasia masquerading as familial glucocorticoid deficiency

Context: Familial glucocorticoid deficiency (FGD) is an autosomal recessive disorder resulting from resistance to the action of ACTH on the adrenal cortex. Affected individuals are deficient in cortisol and, if untreated, are likely to succumb to hypoglycemia and/or overwhelming infection. Mutations of the ACTH receptor (MC2R) and the melanocortin 2 receptor accessory protein (MRAP), FGD types 1 and 2 respectively, account for approximately 45% of cases. Objective: A locus on chromosome 8 has previously been linked to the disease in three families, but no underlying gene defect has to date been identified. Design: The study design comprised single-nucleotide polymorphism genotyping and mutation detection. Setting: The study was conducted at secondary and tertiary referral centers. Patients: Eighty probands from families referred for investigation of the genetic cause of FGD participated in the study. Interventions: There were no interventions. Results: Analysis by single-nucleotide polymorphism array of the genotype of one individual with FGD previously linked to chromosome 8 revealed a large region of homozygosity encompassing the steroidogenic acute regulatory protein gene, STAR. We identified homozygous STAR mutations in this patient and his affected siblings. Screening of our total FGD patient cohort revealed homozygous STAR mutations in a further nine individuals from four other families. Conclusions: Mutations in STAR usually cause lipoid congenital adrenal hyperplasia, a disorder characterized by both gonadal and adrenal steroid deficiency. Our results demonstrate that certain mutations in STAR (R192C and the previously reported R188C) can present with a phenotype indistinguishable from that seen in FGD

Hepatic and adipose phenotype in Alström syndrome

BACKGROUND AND AIMS: Alström syndrome (AS) is a recessive monogenic syndrome characterized by obesity, extreme insulin resistance and multi-organ fibrosis. Despite phenotypically being high risk of non-alcoholic fatty liver disease (NAFLD), there is a lack of data on the extent of fibrosis in the liver and its close links to adipose in patients with AS. Our aim was to characterize the hepatic and adipose phenotype in patients with AS. METHODS: Observational cohort study with comprehensive assessment of metabolic liver phenotype including liver elastography (Fibroscan® ), serum Enhanced Liver Fibrosis (ELF) Panel and liver histology. In addition, abdominal adipose histology and gene expression was assessed. We recruited 30 patients from the UK national AS clinic. A subset of six patients underwent adipose biopsies which was compared with control tissue from nine healthy participants. RESULTS: Patients were overweight/obese (BMI 29.3 (25.95-34.05) kg/m2 ). A total of 80% (24/30) were diabetic; 74% (20/27) had liver ultrasound scanning suggestive of NAFLD. As judged by the ELF panel, 96% (24/25) were categorized as having fibrosis and 10/21 (48%) had liver elastography consistent with advanced liver fibrosis/cirrhosis. In 7/8 selected cases, there was evidence of advanced NAFLD on liver histology. Adipose tissue histology showed marked fibrosis as well as disordered pro-inflammatory and fibrotic gene expression profiles. CONCLUSIONS: NAFLD and adipose dysfunction are common in patients with AS. The severity of liver disease in our cohort supports the need for screening of liver fibrosis in AS.Alström UKThis is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1111/liv.1316