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1.
MedEdPublish (2016) ; 8: 200, 2019.
Article in English | MEDLINE | ID: mdl-38089346

ABSTRACT

This article was migrated. The article was marked as recommended. Introduction: The initial history and examination is a fundamental aspect of clinical practice. Most medical students cultivate this skill through regular undertaking of 'clerkings' during their clinical placements. We designed a written, structured, proforma-based approach to delivery of feedback on student clerkings which also promoted the undertaking of a 'complete clerking' encouraging students to maintain a whole-system holistic approach. Within this paper, we present our findings following its introduction at a London teaching hospital. Methods: Sixty-one medical students on their first clinical attachment within acute medicine were asked to submit at least one full medical clerking for objective appraisal using the structured clerking feedback proforma by a clinical teaching fellow. Students completed a 'pre' and 'post' assessment using Likert Scales at the time of receiving their clerking feedback. Structured interviews of randomly selected students and senior medical educators were also undertaken. Results: Following introduction of the structured feedback proforma, there was a significant increase across all indices of student-perceived utility and satisfaction compared to previously received feedback (which was mostly ad-hoc verbal). Using Likert Scales (1 to 10: 1 representing least effect and 10 representing greatest effect) student assessment of usefulness was 9.0 (versus 6.34 for previous feedback); likelihood of influencing future practice was 8.8 (versus 6.47); extent to which it reinforced the message of a complete clerking was 9.5 (versus 6.13) and extent to which the feedback would encourage them to undertake complete clerkings was 9.0. Free text comments and subsequent interviews of randomly selected students and senior medical educators reinforced the positive perception of this approach. Conclusions: The introduction of a structured clerking feedback proforma can improve the quality and utility of the feedback delivered to medical students on their acute medical clerkings and can promote and reinforce the value of maintaining a whole-system holistic approach.

2.
Diabetologia ; 64(8): 1717-1724, 2021 08.
Article in English | MEDLINE | ID: mdl-33966090

ABSTRACT

AIMS/HYPOTHESIS: The aim of this work was to describe the clinical characteristics of adults with type 1 diabetes admitted to hospital and the risk factors associated with severe coronavirus disease-2019 (COVID-19) in the UK. METHODS: A retrospective cohort study was performed using data collected through a nationwide audit of people admitted to hospital with diabetes and COVID-19, conducted by the Association of British Clinical Diabetologists from March to October 2020. Prespecified demographic, clinical, medication and laboratory data were collected from the electronic and paper medical record systems of the participating hospitals by local clinicians. The primary outcome of the study, severe COVID-19, was defined as death in hospital and/or admission to the adult intensive care unit (AICU). Logistic regression models were used to generate age-adjusted ORs. RESULTS: Forty UK centres submitted data. The final dataset included 196 adults who were admitted to hospital and had both type 1 diabetes and COVID-19 on admission (male sex 55%, white 70%, with mean [SD] age 62 [19] years, BMI 28.3 [7.3] kg/m2 and last recorded HbA1c 76 [31] mmol/mol [9.1 (5.0)%]). The prevalence of pre-existing microvascular disease and macrovascular disease was 56% and 39%, respectively. The prevalence of diabetic ketoacidosis on admission was 29%. A total of 68 patients (35%) died or were admitted to AICU. The proportions of people that died were 7%, 38% and 38% of those aged <55, 55-74 and ≥75 years, respectively. BMI, serum creatinine levels and having one or more microvascular complications were positively associated with the primary outcome after adjusting for age. CONCLUSIONS/INTERPRETATION: In people with type 1 diabetes and COVID-19 who were admitted to hospital in the UK, higher BMI, poorer renal function and presence of microvascular complications were associated with greater risk of death and/or admission to AICU. Risk of severe COVID-19 is reassuringly very low in people with type 1 diabetes who are under 55 years of age without microvascular or macrovascular disease. IN PEOPLE WITH TYPE 1 DIABETES AND COVID-19 ADMITTED TO HOSPITAL IN THE UK, BMI AND ONE OR MORE MICROVASCULAR COMPLICATIONS HAD A POSITIVE ASSOCIATION AND LOW SERUM CREATINE LEVELS HAD A NEGATIVE ASSOCIATION WITH DEATH/ADMISSION TO INTENSIVE CARE UNIT AFTER ADJUSTING FOR AGE.


Subject(s)
COVID-19/epidemiology , COVID-19/pathology , Diabetes Mellitus, Type 1/epidemiology , Patient Admission/statistics & numerical data , Adult , Aged , Aged, 80 and over , COVID-19/complications , COVID-19/therapy , Diabetes Mellitus, Type 1/complications , Diabetes Mellitus, Type 1/therapy , Female , Hospitals/statistics & numerical data , Humans , Male , Middle Aged , Retrospective Studies , Risk Factors , SARS-CoV-2/physiology , Severity of Illness Index , United Kingdom/epidemiology
3.
Case Rep Infect Dis ; 2021: 6649717, 2021.
Article in English | MEDLINE | ID: mdl-33747578

ABSTRACT

BACKGROUND: Infections have long been linked to psychosis and categorised within "secondary" psychoses. To date, there have been few reports of psychosis linked to brucellosis. This case report aims to present one such case. Case Presentation. A 31-year-old man was admitted to a general hospital with pyrexia, severe right upper quadrant pain, and an acute psychosis following a two-week holiday in South East Asia and the Mediterranean. Serological tests revealed that he had brucellosis. Following antibiotic treatment, the psychotic symptoms abated and he was discharged within ten days of hospitalisation. CONCLUSIONS: This case of organic psychosis highlights the importance of considering brucellosis as a rare cause of acute psychosis. The exact mechanism of Brucella-induced psychosis remains unclear.

5.
BMJ Case Rep ; 13(1)2020 Jan 21.
Article in English | MEDLINE | ID: mdl-31969408

ABSTRACT

Methaemoglobinaemia is an extremely rare condition with multiple causes, both genetic and acquired. We present a severe case of methaemoglobinaemia occurring in a Brazilian hairdresser working in the UK. She presented after several days of preparing popular 'Brazilian blowdry' treatments for customers at a hair salon. She had been exposed to multiple volatile chemicals, including formaldehyde, without any respiratory protection, and we postulate that this may have caused her illness. If so, this would be the first published case of methaemoglobinaemia caused by exposure to the volatile components of beauty products.


Subject(s)
Air Pollutants, Occupational/adverse effects , Hair Preparations/adverse effects , Methemoglobinemia/chemically induced , Methemoglobinemia/drug therapy , Methylene Blue/therapeutic use , Occupational Exposure/adverse effects , Enzyme Inhibitors/therapeutic use , Female , Humans , Middle Aged
9.
Blood ; 124(11): 1748-64, 2014 Sep 11.
Article in English | MEDLINE | ID: mdl-25006125

ABSTRACT

Acute inflammation is traditionally characterized by polymorphonuclear leukocytes (PMN) influx followed by phagocytosing macrophage (Mφs) that clear injurious stimuli leading to resolution and tissue homeostasis. However, using the peritoneal cavity, we found that although innate immune-mediated responses to low-dose zymosan or bacteria resolve within days, these stimuli, but not hyperinflammatory stimuli, trigger a previously overlooked second wave of leukocyte influx into tissues that persists for weeks. These cells comprise distinct populations of tissue-resident Mφs (resMφs), Ly6c(hi) monocyte-derived Mφs (moMφs), monocyte-derived dendritic cells (moDCs), and myeloid-derived suppressor cells (MDSCs). Postresolution mononuclear phagocytes were observed alongside lymph node expansion and increased numbers of blood and peritoneal memory T and B lymphocytes. The resMφs and moMφs triggered FoxP3 expression within CD4 cells, whereas moDCs drive T-cell proliferation. The resMφs preferentially clear apoptotic PMNs and migrate to lymph nodes to bring about their contraction in an inducible nitric oxide synthase-dependent manner. Finally, moMφs remain in tissues for months postresolution, alongside altered numbers of T cells collectively dictating the magnitude of subsequent acute inflammatory reactions. These data challenge the prevailing idea that resolution leads back to homeostasis and asserts that resolution acts as a bridge between innate and adaptive immunity, as well as tissue reprogramming.


Subject(s)
Adaptive Immunity/physiology , Phagocytosis/physiology , Adaptive Immunity/drug effects , Animals , CD4-Positive T-Lymphocytes/cytology , CD4-Positive T-Lymphocytes/immunology , Cell Movement/drug effects , Cell Movement/genetics , Cell Movement/immunology , Cell Proliferation/drug effects , Dendritic Cells/cytology , Dendritic Cells/immunology , Forkhead Transcription Factors/genetics , Forkhead Transcription Factors/immunology , Inflammation/chemically induced , Inflammation/genetics , Inflammation/immunology , Macrophages, Peritoneal/cytology , Macrophages, Peritoneal/immunology , Mice , Monocytes/cytology , Monocytes/immunology , Phagocytosis/drug effects , Zymosan/toxicity
10.
Obes Surg ; 24(2): 241-52, 2014 Feb.
Article in English | MEDLINE | ID: mdl-23996294

ABSTRACT

Laparoscopic Roux-en-Y gastric bypass (LRYGBP) reduces appetite and induces significant and sustainable weight loss. Circulating gut hormones changes engendered by LRYGBP are implicated in mediating these beneficial effects. Laparoscopic sleeve gastrectomy (LSG) is advocated as an alternative to LRYGBP, with comparable short-term weight loss and metabolic outcomes. LRYGBP and LSG are anatomically distinct procedures causing differential entero-endocrine cell nutrient exposure and thus potentially different gut hormone changes. Studies reporting the comparative effects of LRYGBP and LSG on appetite and circulating gut hormones are controversial, with no data to date on the effects of LSG on circulating peptide YY3-36 (PYY3-36) levels, the specific PYY anorectic isoform. In this study, we prospectively investigated appetite and gut hormone changes in response to LRYGBP and LSG in adiposity-matched non-diabetic patients. Anthropometric indices, leptin, fasted and nutrient-stimulated acyl-ghrelin, active glucagon-like peptide-1 (GLP-1), PYY3-36 levels and appetite were determined pre-operatively and at 6 and 12 weeks post-operatively in obese, non-diabetic females, with ten undergoing LRYGBP and eight adiposity-matched females undergoing LSG. LRYGBP and LSG comparably reduced adiposity. LSG decreased fasting and post-prandial plasma acyl-ghrelin compared to pre-surgery and to LRYGBP. Nutrient-stimulated PYY3-36 and active GLP-1 concentrations increased post-operatively in both groups. However, LRYGBP induced greater, more sustained PYY3-36 and active GLP-1 increments compared to LSG. LRYGBP suppressed fasting hunger compared to LSG. A similar increase in post-prandial fullness was observed post-surgery following both procedures. LRYGBP and LSG produced comparable enhanced satiety and weight loss. However, LSG and LRYGBP differentially altered gut hormone profiles.


Subject(s)
Appetite , Gastrectomy , Gastric Bypass , Ghrelin/metabolism , Glucagon-Like Peptide 1/metabolism , Laparoscopy , Obesity, Morbid/surgery , Peptide Fragments/metabolism , Peptide YY/metabolism , Adolescent , Adult , Body Mass Index , Female , Humans , Middle Aged , Obesity, Morbid/metabolism , Prospective Studies , Treatment Outcome , Weight Loss
11.
PLoS One ; 8(8): e70735, 2013.
Article in English | MEDLINE | ID: mdl-23950990

ABSTRACT

The prevalence of severe obesity, defined as body mass index (BMI) ≥ 35.0 kg/m(2), is rising rapidly. Given the disproportionately high health burden and healthcare costs associated with this condition, understanding the underlying aetiology, including predisposing genetic factors, is a biomedical research priority. Previous studies have suggested that severe obesity represents an extreme tail of the population BMI variation, reflecting shared genetic factors operating across the spectrum. Here, we sought to determine whether a panel of 32 known common obesity-susceptibility variants contribute to severe obesity in patients (n = 1,003, mean BMI 48.4 ± 8.1 kg/m(2)) attending bariatric surgery clinics in two European centres. We examined the effects of these 32 common variants on obesity risk and BMI, both as individual markers and in combination as a genetic risk score, in a comparison with normal-weight controls (n = 1,809, BMI 18.0-24.9 kg/m(2)); an approach which, to our knowledge, has not been previously undertaken in the setting of a bariatric clinic. We found strong associations with severe obesity for SNP rs9939609 within the FTO gene (P = 9.3 × 10(-8)) and SNP rs2815752 near the NEGR1 gene (P = 3.6 × 10(-4)), and directionally consistent nominal associations (P<0.05) for 12 other SNPs. The genetic risk score associated with severe obesity (P = 8.3 × 10(-11)) but, within the bariatric cohort, this score did not associate with BMI itself (P = 0.264). Our results show significant effects of individual BMI-associated common variants within a relatively small sample size of bariatric patients. Furthermore, the burden of such low-penetrant risk alleles contributes to severe obesity in this population. Our findings support that severe obesity observed in bariatric patients represents an extreme tail of the population BMI variation. Moreover, future genetic studies focused on bariatric patients may provide valuable insights into the pathogenesis of obesity at a population level.


Subject(s)
Cell Adhesion Molecules, Neuronal/genetics , Genetic Predisposition to Disease/genetics , Obesity, Morbid/genetics , Polymorphism, Single Nucleotide , Proteins/genetics , Adult , Alpha-Ketoglutarate-Dependent Dioxygenase FTO , Bariatric Surgery , Body Mass Index , Case-Control Studies , Female , GPI-Linked Proteins/genetics , Gene Frequency , Genetic Predisposition to Disease/ethnology , Genome-Wide Association Study , Genotype , Humans , Italy , Logistic Models , London , Male , Middle Aged , Models, Genetic , Obesity, Morbid/ethnology , Obesity, Morbid/surgery , Referral and Consultation , White People/genetics
12.
Appl Physiol Nutr Metab ; 38(9): 947-52, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23905660

ABSTRACT

High-intensity intermittent exercise induces physiological adaptations similar to energy-matched continuous exercise, but the comparative appetite and energy balance responses are unknown. Twelve healthy males (mean ± SD: age, 22 ± 3 years; body mass index, 23.7 ± 3.0 kg·m(-2); maximum oxygen uptake, 52.4 ± 7.1 mL·kg(-1)·min(-1)) completed three 8 h trials (control, steady-state exercise (SSE), high-intensity intermittent exercise (HIIE)) separated by 1 week. Trials commenced upon completion of a standardized breakfast. Exercise was performed from hour 2 to hour 3. In SSE, 60 min of cycling at 59.5% ± 1.6% of maximum oxygen uptake was performed. In HIIE, ten 4-min cycling intervals were completed at 85.8% ± 4.0% of maximum oxygen uptake, with a 2-min rest between each interval. A standardized lunch and an ad libitum afternoon meal were provided at hours 3.75 and 7, respectively. Appetite ratings and peptide YY3-36 concentrations were measured throughout each trial. Appetite was acutely suppressed during exercise, but more so during HIIE (p < 0.05). Peptide YY3-36 concentrations increased significantly upon cessation of exercise in SSE (p = 0.002), but were highest in the hours after exercise in HIIE (p = 0.05). Exercise energy expenditure was not different between HIIE and SSE (p = 0.649), but perceived exertion was higher in HIIE (p < 0.0005). Ad libitum energy intake did not differ between trials (p = 0.833). Therefore, relative energy intake (energy intake minus the net energy expenditure of exercise) was lower in the SSE and HIIE trials than in the control trial (control, 4759 ± 1268 kJ; SSE, 2362 ± 1224 kJ; HIIE, 2523 ± 1402 kJ; p < 0.0005). An acute bout of energy-matched continuous exercise and HIIE were equally effective at inducing an energy deficit without stimulating compensatory increases in appetite.


Subject(s)
Appetite , Energy Intake , Energy Metabolism , Exercise , Humans , Rest
13.
J Clin Invest ; 123(8): 3539-51, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23867619

ABSTRACT

Polymorphisms in the fat mass and obesity-associated gene (FTO) are associated with human obesity and obesity-prone behaviors, including increased food intake and a preference for energy-dense foods. FTO demethylates N6-methyladenosine, a potential regulatory RNA modification, but the mechanisms by which FTO predisposes humans to obesity remain unclear. In adiposity-matched, normal-weight humans, we showed that subjects homozygous for the FTO "obesity-risk" rs9939609 A allele have dysregulated circulating levels of the orexigenic hormone acyl-ghrelin and attenuated postprandial appetite reduction. Using functional MRI (fMRI) in normal-weight AA and TT humans, we found that the FTO genotype modulates the neural responses to food images in homeostatic and brain reward regions. Furthermore, AA and TT subjects exhibited divergent neural responsiveness to circulating acyl-ghrelin within brain regions that regulate appetite, reward processing, and incentive motivation. In cell models, FTO overexpression reduced ghrelin mRNA N6-methyladenosine methylation, concomitantly increasing ghrelin mRNA and peptide levels. Furthermore, peripheral blood cells from AA human subjects exhibited increased FTO mRNA, reduced ghrelin mRNA N6-methyladenosine methylation, and increased ghrelin mRNA abundance compared with TT subjects. Our findings show that FTO regulates ghrelin, a key mediator of ingestive behavior, and offer insight into how FTO obesity-risk alleles predispose to increased energy intake and obesity in humans.


Subject(s)
Appetite , Ghrelin/blood , Proteins/genetics , Acyltransferases/genetics , Acyltransferases/metabolism , Adolescent , Adult , Alpha-Ketoglutarate-Dependent Dioxygenase FTO , Animals , Brain/physiology , Eating/psychology , Food , Functional Neuroimaging , Gene Expression , Gene Expression Regulation , Genetic Association Studies , HEK293 Cells , Humans , Magnetic Resonance Imaging , Male , Methylation , Mice , Mice, Knockout , Polymorphism, Single Nucleotide , Proteins/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism , Reward , Ribosomal Proteins/genetics , Ribosomal Proteins/metabolism , Young Adult
14.
PLoS One ; 8(3): e59407, 2013.
Article in English | MEDLINE | ID: mdl-23527188

ABSTRACT

BACKGROUND: Neuronatin (NNAT) is an endoplasmic reticulum proteolipid implicated in intracellular signalling. Nnat is highly-expressed in the hypothalamus, where it is acutely regulated by nutrients and leptin. Nnat pre-mRNA is differentially spliced to create Nnat-α and -ß isoforms. Genetic variation of NNAT is associated with severe obesity. Currently, little is known about the long-term regulation of Nnat. METHODS: Expression of Nnat isoforms were examined in the hypothalamus of mice in response to acute fast/feed, chronic caloric restriction, diet-induced obesity and modified gastric bypass surgery. Nnat expression was assessed in the central nervous system and gastrointestinal tissues. RTqPCR was used to determine isoform-specific expression of Nnat mRNA. RESULTS: Hypothalamic expression of both Nnat isoforms was comparably decreased by overnight and 24-h fasting. Nnat expression was unaltered in diet-induced obesity, or subsequent switch to a calorie restricted diet. Nnat isoforms showed differential expression in the hypothalamus but not brainstem after bypass surgery. Hypothalamic Nnat-ß expression was significantly reduced after bypass compared with sham surgery (P = 0.003), and was positively correlated with post-operative weight-loss (R(2) = 0.38, P = 0.01). In contrast, Nnat-α expression was not suppressed after bypass surgery (P = 0.19), and expression did not correlate with reduction in weight after surgery (R(2) = 0.06, P = 0.34). Hypothalamic expression of Nnat-ß correlated weakly with circulating leptin, but neither isoform correlated with fasting gut hormone levels post- surgery. Nnat expression was detected in brainstem, brown-adipose tissue, stomach and small intestine. CONCLUSIONS: Nnat expression in hypothalamus is regulated by short-term nutrient availability, but unaltered by diet-induced obesity or calorie restriction. While Nnat isoforms in the hypothalamus are co-ordinately regulated by acute nutrient supply, after modified gastric bypass surgery Nnat isoforms show differential expression. These results raise the possibility that in the radically altered nutrient and hormonal milieu created by bypass surgery, resultant differential splicing of Nnat pre-mRNA may contribute to weight-loss.


Subject(s)
Gastric Bypass , Gene Expression Regulation/physiology , Hypothalamus/metabolism , Membrane Proteins/metabolism , Nerve Tissue Proteins/metabolism , Obesity/metabolism , RNA Splicing/physiology , Adipose Tissue/metabolism , Analysis of Variance , Animals , Caloric Restriction , Gastrointestinal Tract/metabolism , Gene Expression Profiling , Membrane Proteins/genetics , Mice , Nerve Tissue Proteins/genetics , Protein Isoforms/metabolism , Reverse Transcriptase Polymerase Chain Reaction
15.
Br J Hosp Med (Lond) ; 73(8): C119-23, 2012 Aug.
Article in English | MEDLINE | ID: mdl-22875534
16.
Diabetes ; 60(3): 810-8, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21292870

ABSTRACT

OBJECTIVE: Bariatric surgery causes durable weight loss. Gut hormones are implicated in obesity pathogenesis, dietary failure, and mediating gastrointestinal bypass (GIBP) surgery weight loss. In mice, we determined the effects of diet-induced obesity (DIO), subsequent dieting, and GIBP surgery on ghrelin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). To evaluate PYY's role in mediating weight loss post-GIBP, we undertook GIBP surgery in PyyKO mice. RESEARCH DESIGN AND METHODS: Male C57BL/6 mice randomized to a high-fat diet or control diet were killed at 4-week intervals. DIO mice underwent switch to ad libitum low-fat diet (DIO-switch) or caloric restriction (CR) for 4 weeks before being killed. PyyKO mice and their DIO wild-type (WT) littermates underwent GIBP or sham surgery and were culled 10 days postoperatively. Fasting acyl-ghrelin, total PYY, active GLP-1 concentrations, stomach ghrelin expression, and colonic Pyy and glucagon expression were determined. Fasting and postprandial PYY and GLP-1 concentrations were assessed 30 days postsurgery in GIBP and sham pair-fed (sham.PF) groups. RESULTS: DIO progressively reduced circulating fasting acyl-ghrelin, PYY, and GLP-1 levels. CR and DIO-switch caused weight loss but failed to restore circulating PYY to weight-appropriate levels. After GIBP, WT mice lost weight and exhibited increased circulating fasting PYY and colonic Pyy and glucagon expression. In contrast, the acute effects of GIBP on body weight were lost in PyyKO mice. Fasting PYY and postprandial PYY and GLP-1 levels were increased in GIBP mice compared with sham.PF mice. CONCLUSIONS: PYY plays a key role in mediating the early weight loss observed post-GIBP, whereas relative PYY deficiency during dieting may compromise weight-loss attempts.


Subject(s)
Diet, Reducing , Ghrelin/metabolism , Obesity/metabolism , Obesity/surgery , Peptide YY/metabolism , Weight Loss/physiology , Analysis of Variance , Animals , Colon/metabolism , Diet, Fat-Restricted , Enzyme-Linked Immunosorbent Assay , Gastric Bypass , Gastric Mucosa/metabolism , Glucagon/metabolism , Glucagon-Like Peptide 1/metabolism , Leptin/blood , Male , Mice , Radioimmunoassay , Random Allocation , Reverse Transcriptase Polymerase Chain Reaction
17.
Trends Endocrinol Metab ; 21(6): 337-44, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20133150

ABSTRACT

Bariatric surgery is the most effective treatment modality for obesity, resulting in durable weight loss and amelioration of obesity-associated comorbidities, particularly type 2 diabetes mellitus (T2DM). Moreover, the metabolic benefits of bariatric surgery occur independently of weight loss. There is increasing evidence that surgically induced alterations in circulating gut hormones mediate these beneficial effects of bariatric surgery. Here, we summarise current knowledge on the effects of different bariatric procedures on circulating gut hormone levels. We also discuss the theories that have been put forward to explain the weight loss and T2DM resolution following bariatric surgery. Understanding the mechanisms mediating these beneficial outcomes of bariatric surgery could result in new non-surgical treatment strategies for obesity and T2DM.


Subject(s)
Bariatric Surgery , Caloric Restriction , Diabetes Mellitus, Type 2/metabolism , Obesity/surgery , Weight Loss/physiology , Bariatric Surgery/classification , Bariatric Surgery/methods , Diabetes Mellitus, Type 2/surgery , Energy Metabolism , Ghrelin/metabolism , Glucagon-Like Peptide 1/metabolism , Humans , Obesity/metabolism , Peptide YY/metabolism
18.
Mol Cell Endocrinol ; 316(2): 120-8, 2010 Mar 25.
Article in English | MEDLINE | ID: mdl-19563862

ABSTRACT

Obesity is one of the greatest public health challenges of the 21st century with 1.6 billion adults currently classified as being overweight and 400 million as obese. Obesity is causally associated with type 2 diabetes, hypertension, cardiovascular disease, obstructive sleep apnoea and certain forms of cancer and is now one of the leading causes of mortality and morbidity worldwide. The gastrointestinal tract is the largest endocrine organ in the body producing hormones that have important sensing and signaling roles in regulating body weight and energy expenditure. The last decade has witnessed a marked increase in our understanding of the role of gut hormones in energy homeostasis. Consequently, strategies aimed at modulating circulating gut hormone concentrations or targeting their receptors are being developed as potential pharmacotherapies for obesity. This review summarizes the current knowledge regarding the mechanisms, sites of action and effects of the anorectic gut hormones peptide tyrosine-tyrosine (PYY), pancreatic polypeptide (PP), oxyntomodulin, and amylin and of the unique orexigenic hormone, ghrelin.


Subject(s)
Body Weight/physiology , Energy Metabolism/physiology , Gastrointestinal Hormones/metabolism , Homeostasis/physiology , Amyloid/genetics , Amyloid/metabolism , Animals , Gastrointestinal Hormones/genetics , Gastrointestinal Tract/anatomy & histology , Gastrointestinal Tract/metabolism , Ghrelin/genetics , Ghrelin/metabolism , Humans , Islet Amyloid Polypeptide , Obesity/complications , Obesity/physiopathology , Obesity/surgery , Oxyntomodulin/genetics , Oxyntomodulin/metabolism , Pancreatic Polypeptide/genetics , Pancreatic Polypeptide/metabolism , Peptide YY/genetics , Peptide YY/metabolism
19.
Gastroenterology ; 136(7): 2115-26, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19233179

ABSTRACT

BACKGROUND & AIMS: Gut hormones represent attractive therapeutic targets for the treatment of obesity and type 2 diabetes. However, controversy surrounds the effects that adiposity, dietary manipulations, and bariatric surgery have on their circulating concentrations. We sought to determine whether these discrepancies are due to methodologic differences. METHODS: Ten normal-weight males participated in a 4-way crossover study investigating whether fasting appetite scores, plasma acyl-ghrelin, active glucagon-like peptide-1 (GLP-1), and peptide YY3-36 (PYY3-36) levels are altered by study-induced stress, prior food consumption, and sample processing. RESULTS: Study visit order affected anxiety, plasma cortisol, and temporal profiles of appetite and plasma PYY3-36, with increased anxiety and cortisol concentrations on the first study day. Plasma cortisol area under the curve (AUC) correlated positively with plasma PYY3-36 AUC. Despite a 14-hour fast, baseline hunger, PYY3-36 concentrations, temporal appetite profiles, PYY3-36 AUC, and active GLP-1 were affected by the previous evening's meal. Sample processing studies revealed that sample acidification and esterase inhibition are required when measuring acyl-ghrelin and dipeptidyl-peptidase IV inhibitor addition for active GLP-1. However, plasma PYY3-36 concentrations were unaffected by addition of dipeptidyl-peptidase IV. CONCLUSIONS: Accurate assessment of appetite, feeding behavior, and gut hormone concentrations requires standardization of prior food consumption and subject acclimatization to the study protocol. Moreover, because of the labile nature of acyl-ghrelin and active GLP-1, specialized sample processing needs to be undertaken.


Subject(s)
Appetite/physiology , Ghrelin/metabolism , Glucagon-Like Peptide 1/metabolism , Hunger/physiology , Hydrocortisone/metabolism , Peptide YY/metabolism , Adaptation, Psychological , Adult , Analysis of Variance , Area Under Curve , Body Weight , Cross-Over Studies , Feeding Behavior , Gastrointestinal Hormones/analysis , Gastrointestinal Hormones/metabolism , Humans , Male , Probability , Reference Standards , Reference Values , Risk Factors , Sampling Studies , Sensitivity and Specificity , Stress, Psychological
20.
J Physiol ; 587(1): 19-25, 2009 Jan 15.
Article in English | MEDLINE | ID: mdl-19064614

ABSTRACT

The last decade has witnessed a marked increase in our understanding of the importance of gut hormones in the regulation of energy homeostasis. In particular, the discovery that the gut hormone peptide YY 3-36 (PYY3-36) reduced feeding in obese rodents and humans fuelled interest in the role of PYY3-36 in body weight regulation. Pharmacological and genetic approaches have revealed that the Y2-receptor mediates the anorectic effects of PYY3-36 whilst mechanistic studies in rodents identified the hypothalamus, vagus and brainstem regions as potential sites of action. More recently, using functional brain imaging techniques in humans, PYY3-36 was found to modulate neuronal activity within hypothalamic and brainstem, and brain regions involved in reward processing. Several lines of evidence suggest that low circulating PYY concentrations predispose towards the development and or maintenance of obesity. Subjects with reduced postprandial PYY release exhibit lower satiety and circulating PYY levels that correlate negatively with markers of adiposity. In addition, mice lacking PYY are hyperphagic and become obese. Conversely, chronic PYY3-36 administration to obese rodents reduces adiposity, and transgenic mice with increased circulating PYY are resistant to diet-induced obesity. Moreover, there is emerging evidence that PYY3-36 may partly mediate the reduced appetite and weight loss benefits observed post-gastric bypass surgery. Taken together these findings, coupled with the retained responsiveness of obese subjects to the effects of PYY3-36, suggest that targeting the PYY system may offer a therapeutic strategy to help treat obesity.


Subject(s)
Appetite Regulation/physiology , Obesity/physiopathology , Peptide YY/physiology , Animals , Eating/drug effects , Eating/physiology , Energy Metabolism/drug effects , Gastric Bypass , Humans , Obesity/drug therapy , Obesity/surgery , Peptide Fragments , Peptide YY/administration & dosage , Receptors, Gastrointestinal Hormone/drug effects , Receptors, Gastrointestinal Hormone/physiology , Weight Loss/physiology
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