Metabolomic profiling to dissect the role of visceral fat in cardiometabolic health

OBJECTIVE: Abdominal obesity is associated with increased risk of type 2 diabetes (T2D) and cardiovascular disease. The aim of this study was to assess whether metabolomic markers of T2D and blood pressure (BP) act on these traits via visceral fat (VF) mass.

METHODS: Metabolomic profiling of 280 fasting plasma metabolites was conducted on 2,401 women from TwinsUK. The overlap was assessed between published metabolites associated with T2D, insulin resistance, or BP and those that were identified to be associated with VF (after adjustment for covariates) measured by dual-energy X-ray absorptiometry.

RESULTS: In addition to glucose, six metabolites were strongly associated with both VF mass and T2D: lactate and branched-chain amino acids, all of them related to metabolism and the tricarboxylic acid cycle; on average, 38.5% of their association with insulin resistance was mediated by their association with VF mass. Five metabolites were associated with BP and VF mass including the inflammation-associated peptide HWESASXX, the steroid hormone androstenedione, lactate, and palmitate. On average, 29% of their effect on BP was mediated by their association with VF mass.

CONCLUSIONS: Little overlap was found between the metabolites associated with BP and those associated with insulin resistance via VF mass.

Treatment of lean and diet-induced obesity (DIO) mice with a novel stable obestatin analogue alters plasma metabolite levels as detected by untargeted LC–MS metabolomics

Introduction: Obestatin is a controversial gastrointestinal peptide purported to have metabolic actions.

Objectives: This study investigated whether treatment with a stable obestatin analogue (PEG-OB(Cys10, Cys13)) changed plasma metabolite levels firstly in lean and subsequently in diet-induced obesity (DIO) C57BL6/J mice.

Methods: Untargeted LC-HRMS metabolomics experiments were carried out in ESI + mode with plasma extracts from both groups of animals. Data were normalised, multivariate and univariate statistical analysis performed and metabolites of interest putatively identified.

Results: In lean mice, 39 metabolites were significantly changed by obestatin treatment and the majority of these were increased, including various C16 and C18 moieties of phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and monoacylglycerol, along with vitamin A, vitamin D3, tyrosine, acetylcarnitine and 2α-(hydroxymethyl)-5α-androstane-3β,17β-diol. Decreased concentrations of glycolithocholic acid, 3-dehydroteasterone and various phospholipids were observed. In DIO mice, 25 metabolites were significantly affected and strikingly, the magnitudes of changes here were generally much greater in DIO mice than in lean mice, and in contrast, the majority of metabolite changes were decreases. Four metabolites affected in both groups included glycolithocholic acid, and three different long-chain (C18) phospholipid molecules (phosphatidylethanolamine, platelet activating factor (PAF), and monoacylglycerol). Metabolites exclusively affected in DIO mice included various phosphatidylcholines, lysophosphatidylcholines and fatty acyls, as well as creatine and oxidised glutathione.

Conclusion: This investigation demonstrates that obestatin treatment affects phospholipid turnover and influences lipid homeostasis, whilst providing convincing evidence that obestatin may be acting to ameliorate diet-induced impairments in lipid metabolism, and it may influence steroid, bile acid, PAF and glutathione metabolism.

Glycosylation is an Androgen-Regulated Process Essential for Prostate Cancer Cell Viability

Steroid androgen hormones play a key role in the progression and treatment of prostate cancer, with androgen deprivation therapy being the first-line treatment used to control cancer growth. Here we apply a novel search strategy to identify androgen-regulated cellular pathways that may be clinically important in prostate cancer. Using RNASeq data, we searched for genes that showed reciprocal changes in expression in response to acute androgen stimulation in culture, and androgen deprivation in patients with prostate cancer. Amongst 700 genes displaying reciprocal expression patterns we observed a significant enrichment in the cellular process glycosylation. Of 31 reciprocally-regulated glycosylation enzymes, a set of 8 (GALNT7, ST6GalNAc1, GCNT1, UAP1, PGM3, CSGALNACT1, ST6GAL1 and EDEM3) were significantly up-regulated in clinical prostate carcinoma. Androgen exposure stimulated synthesis of glycan structures downstream of this core set of regulated enzymes including sialyl-Tn (sTn), sialyl Lewis(X) (SLe(X)), O-GlcNAc and chondroitin sulphate, suggesting androgen regulation of the core set of enzymes controls key steps in glycan synthesis. Expression of each of these enzymes also contributed to prostate cancer cell viability. This study identifies glycosylation as a global target for androgen control, and suggests loss of specific glycosylation enzymes might contribute to tumour regression following androgen depletion therapy.

Métabolisme des glucocorticoïdes dans le poumon murin en développement : la voie surrénalienne

Lorsqu’une femme est à risque d’accoucher prématurément, des glucocorticoïdes lui seront administrés afin d’accélérer la maturation pulmonaire du bébé. Après la naissance, différents protocoles peuvent être mis en place pour aider l’enfant à respirer dont l’administration du surfactant et la ventilation. Les glucocorticoïdes ont un effet positif sur la maturation pulmonaire. Par contre, ils nuisent au processus de la septation après la naissance. Les glucocorticoïdes retrouvés dans le poumon en développement peuvent provenir de deux sources, soit de la voie classique de la synthèse des glucocorticoïdes par les surrénales, soit des gènes exprimés dans le poumon. Les sites d’expression des gènes codant pour les enzymes de la synthèse des glucocorticoïdes dans le poumon sont inconnus ainsi que le gène de la 20α-hydroxystéroïde déshydrogénase (20α-HSD). Cette dernière inactive le substrat et le produit de la 21-hydroxylase. Des poumons de fœtus de souris au jour de gestation 15,5, 17,5 et 19,5 ainsi que de souriceaux âgés de 0, 5 et 15 jours ont été utilisés pour des hybridations in situ. Cette étude a montré qu’avant la naissance, l’ARNm de la 21-hydroxylase est situé au niveau des cellules épithéliales distales alors que l’ARNm de la 20α-HSD se retrouve plutôt au niveau des capillaires. Les gènes de la 21-hydroxylase et de la 20α-HSD sont exprimés dans les cellules épithéliales proximales ainsi que dans les cellules endothéliales de veines dans la période entourant la naissance. À la fin du stade sacculaire et pendant le stade alvéolaire, le gène de la 21-hydroxylase est exprimé seulement dans les septa et les parois minces tout comme le gène de la 20α-HSD sauf dans le stade alvéolaire où il n’y avait pas de signal significatif. Ainsi, ces résultats suggèrent que la 20α-HSD pourrait participer au contrôle du niveau d’activité de la 21-hydroxylase en modulant la disponibilité de son substrat.

Analysis of the role of the transcription factor C/EBPβ in controlling uterine functions during early pregnancy

Embryo implantation into the endometrium is a complex biological process involving the integration of steroid hormone signaling, endometrial tissue remodeling and maternal- fetal communications. A successful pregnancy is the outcome of the timely integration of these events during the early stages of implantation. The involvement of ovarian steroid hormones, estrogen (E) and progesterone (P), acting through their cognate receptors, is essential for uterine functions during pregnancy. The molecular mechanisms that control the process of implantation are undergoing active exploration. Through our recent efforts, we identified the transcription factor, CCAAT Enhancer Binding Protein Beta (C/EBPb) as a prominent target of estrogen and progesterone signaling in the uterus. The development of a C/EBPb-null mouse model, which is infertile, presented us with an opportunity to analyze the role of this molecule in uterine function. We discovered that C/EBPb functions in two distinct manners: (i) by acting as a mediator of E-induced proliferation of the uterine epithelium and (ii) by controlling uterine stromal cell differentiation, a process known as decidualization, during pregnancy. My studies have delineated important mechanisms by which E regulates C/EBPb expression to induce DNA replication and prevent apoptosis of uterine epithelial cells during E-induced epithelial growth. In subsequent studies, I analyzed the role of C/EBPb in decidualization and uncovered a unique mechanism by which C/EBPb regulates the synthesis of a unique laminin-containing extracellular matrix (ECM) that supports stromal cell differentiation and embryo invasion. In order to better define the role of laminin in implantation, we developed a laminin gamma 1-conditional knockout mouse model. This is currently an area of ongoing investigation. The information gained from our analysis of C/EBPb function in the uterus provides new insights into the mechanisms of steroid hormone action during early pregnancy. Ultimately, our findings may aid in the understanding of dysregulation of hormone-controlled pathways that underlie early pregnancy loss and infertility in women.

Developmental programming of polycystic ovary syndrome (PCOS): prenatal androgens establish pancreatic islet α/β cell ratio and subsequent insulin secretion

Exogenous androgenic steroids applied to pregnant sheep programmes a PCOS-like phenotype in female offspring. Via ultrasound guidance we applied steroids directly to ovine fetuses at d62 and d82 of gestation, and examined fetal (day 90 gestation) and postnatal (11 months old) pancreatic structure and function. Of three classes of steroid agonists applied (androgen - Testosterone propionate (TP), estrogen - Diethystilbesterol (DES) and glucocorticoid - Dexamethasone (DEX)), only androgens (TP) caused altered pancreatic development. Beta cell numbers were significantly elevated in prenatally androgenised female fetuses (P=0.03) (to approximately the higher numbers found in male fetuses), whereas alpha cell counts were unaffected, precipitating decreased alpha:beta cell ratios in the developing fetal pancreas (P=0.001), sustained into adolescence (P=0.0004). In adolescence basal insulin secretion was significantly higher in female offspring from androgen-excess pregnancies (P=0.045), and an exaggerated, hyperinsulinaemic response to glucose challenge (P=0.0007) observed, whereas prenatal DES or DEX treatment had no effects upon insulin secretion. Postnatal insulin secretion correlated with beta cell numbers (P=0.03). We conclude that the pancreas is a primary locus of androgenic stimulation during development, giving rise to postnatal offspring whose pancreas secreted excess insulin due to excess beta cells in the presence of a normal number of alpha cells.

Determinants of self-medication with NSAIDs in a Portuguese community pharmacy

Background: Non-steroid anti-inflammatory drugs (NSAIDs) are a widely used therapeutic group in the world, and particularly in the Portuguese population. Objective: To compare NSAID’s use by prescription and self-medication acquisition and to determine the pattern of indication of NSAIDs, their usage profile and possible implications for patients’ safety. Methods: A cross-sectional design was used where individuals presenting at a community pharmacy requesting NSAIDs during the study period (one month) were invited to answer a face-to-face interview where socio-demographic characteristics, the indication pattern and previous experience of side effects were assessed. A follow-up interview was performed one week later to assess the incidence of adverse effects. The study was ethically approved. Results: A sample of 130 NSAIDs users was recruited, comprising mostly women (n=87; 66.9%), actively employed (n=77; 59.2%) and presenting a mean age of 49.5 years old (SD=20.49). An equal proportion of individuals acquired NSAIDs by self-medication and with medical prescription (n=65; 50%). Over 4/5 of patients (n=57; 87.7%) acquiring NSAIDs without a prescription were self-medicated by their own initiative, and only 10.8% (n=7) had been advised by the pharmacist. The most commonly acquired active substances were ibuprofen and diclofenac. Self-medicated users more frequently resorted to topical NSAIDs following short term treatments. The major underlying condition motivating NSAIDs sought were musculoskeletal disorders (45.0%), regardless of the regimen. An important proportion of prevalent users of NSAIDs reported previous experience of adverse effects (11.3%). One week after initiating NSAID therapy, a small proportion of patients reported incidence of adverse effects. Conclusion: Self-medication with NSAIDs is sought for numerous medical conditions. Reported adverse effects (prevalent and incident) confirm the need for a more rational use of NSAIDs and ongoing pharmacovigilance.

Caracterização genotípica de doentes portugueses com patologias associadas ao complexo multienzimático lisossomal: sialidose e galactosialidose

Dissertação de mestrado em Biologi apresentada à Faculdade de Ciências da Universidade do Porto, 2008

Hashimoto’s Encephalopathy: An Unusual Cause of Autoimmune Encephalopathy in a Clinically and Biochemically Euthyroid Patient

Objectives: To highlight the occurrence of Hashimoto’s encephalopathy – a steroid-responsive encephalopathy associated with elevated antithyroid antibodies. Material and methods: We describe a clinically and biochemically euthyroid patient with an encephalopathy presenting with headache, mild confusion and personality changes for 6 weeks and tonic–clonic seizures upon admission Results: There was no obvious infective or metabolic cause. The patient had a high titre of antithyroid antibodies and responded to steroid therapy. Conclusion: This uncommon disease needs to be considered in patients presenting with neurological symptoms that remain unexplained after routine standard investigations, even when the patient is euthyroid. Early diagnosis is important, as this is a treatable condition.

Iatrogenic Cushing’s syndrome and Secondary Adrenal Insufficiency in an HIV Patientreceiving Fluticasone and Ritonavir

Objectives: To illustrate that the protease inhibitor (PI) ritonavir, widely used as part of the treatment for HIV, might cause drug–drug interactions with inhaled corticosteroids. Material and methods: A case report is presented. Results: An HIV-positive patient presented with gradually changing body composition that was ascribed to lipodystrophy. Finally, iatrogenic Cushing's syndrome with secondary adrenal insufficiency was diagnosed due to a drug–drug interaction of ritonavir and fluticasone. Conclusion: Lipodystrophy might mimic Cushing's syndrome. The combination of ritonavir and inhaled fluticasone may lead to systemic steroid excess causing Cushing's syndrome and secondary adrenal insufficiency.

Hepcidin and Ferritin Levels in Fever of Unknown Origin: Is There a New Biomarker?

Background and objectives: Significantly elevated serum ferritin levels are associated with both iron overload and some inflammatory conditions. Hepcidin is a protein that interferes with iron absorption in inflammatory states and acts as an acute-phase reactant. Materials and methods: Here we report the case a 33-year-old patient who presented with high fever, skin lesions and arthralgia lasting for 2 weeks. His ferritin level was 13,800 µg/l and his hepcidin level was 61 ng/dl. Results: The final diagnosis was adult onset Still's disease. The condition evolved satisfactorily with steroid treatment, but after several weeks the patient presented with an unexpected recurrence. Conclusions: Hepcidin is a good inflammatory marker that could be useful in the differential diagnosis of hyperferritinaemia.