Metabolic-associated fatty liver disease and hepatocellular carcinoma: a prospective study of characteristics and response to therapy.

BACKGROUND AND AIM: The rising incidence of hepatocellular carcinoma (HCC) in Australia is related to increasing rates of metabolic-associated fatty liver disease (MAFLD). This study aimed to prospectively characterize the metabolic profile, lifestyle, biometric features, and response to treatment of HCC patients in an Australian population. METHOD: Multicenter prospective cohort analysis of newly diagnosed HCC patients at six multidisciplinary team meetings over a 2-year period. RESULTS: Three hundred and thirteen (313) newly diagnosed HCC patients with MAFLD (n = 77), MAFLD plus other liver disease (n = 57) (the "mixed" group), and non-MAFLD (n = 179) were included in the study. Alcohol-associated liver disease (ALD) (43%) and MAFLD (43%) were the most common underlying liver diseases. MAFLD-HCC patients were older (73 years vs 67 years vs 63 years), more likely to be female (40% vs 14% vs 20%), less likely to have cirrhosis (69% vs 88% vs 85%), showed higher ECOG, and were less likely to be identified by screening (29% vs 53% vs 45%). Metabolic syndrome was more prevalent in the MAFLD and mixed groups. The severity of underlying liver disease and HCC characteristics were the same across groups. While the MAFLD population self-reported more sedentary lifestyles, reported dietary patterns were no different across the groups. Dyslipidemia was associated with tumor size, and those taking statins had a lower recurrence rate. CONCLUSION: Equal to ALD, MAFLD is now the most common underlying liver disease seen in HCC patients in Australia. Future HCC prevention screening and treatment strategies need to take this important group of patients into consideration.

Rare coding variant analysis in a large cohort of Ashkenazi Jewish families with inflammatory bowel disease.

Rare variants are thought to contribute to the genetics of inflammatory bowel disease (IBD), which is more common amongst the Ashkenazi Jewish (AJ) population. A family-based approach using exome sequencing of AJ individuals with IBD was employed with a view to identify novel rare genetic variants for this disease. Exome sequencing was performed on 960 Jewish individuals including 513 from 199 multiplex families with up to eight cases. Rare, damaging variants in loci prioritized by linkage analysis and those shared by multiple affected individuals within the same family were identified. Independent evidence of association of each variant with disease was assessed. A number of candidate variants were identified, including in genes involved in the immune system. The ability to achieve statistical significance in independent case/control replication data was limited by power and was only achieved for variants in the well-established Crohn's disease gene, NOD2. This work demonstrates the challenges of identifying disease-associated rare damaging variants from exome data, even amongst a favorable cohort of familial cases from a genetic isolate. Further research of the prioritized rare candidate variants is required to confirm their association with the disease.

l-phenylalanine modulates gut hormone release and glucose tolerance, and suppresses food intake through the calcium-sensing receptor in rodents.

OBJECTIVE: High-protein diets (HPDs) are associated with greater satiety and weight loss than diets rich in other macronutrients. The exact mechanisms by which HPDs exert their effects are unclear. However, evidence suggests that the sensing of amino acids produced as a result of protein digestion may have a role in appetite regulation and satiety. We investigated the effects of l-phenylalanine (L-Phe) on food intake and glucose homeostasis in rodents. METHODS: We investigated the effects of the aromatic amino-acid and calcium-sensing receptor (CaSR) agonist l-phenylalanine (L-Phe) on food intake and the release of the gastrointestinal (GI) hormones peptide YY (PYY), glucagon-like peptide-1 (GLP-1) and ghrelin in rodents, and the role of the CaSR in mediating these effects in vitro and in vivo. We also examined the effect of oral l-Phe administration on glucose tolerance in rats. RESULTS: Oral administration of l-Phe acutely reduced food intake in rats and mice, and chronically reduced food intake and body weight in diet-induced obese mice. Ileal l-Phe also reduced food intake in rats. l-Phe stimulated GLP-1 and PYY release, and reduced plasma ghrelin, and also stimulated insulin release and improved glucose tolerance in rats. Pharmacological blockade of the CaSR attenuated the anorectic effect of intra-ileal l-Phe in rats, and l-Phe-induced GLP-1 release from STC-1 and primary L cells was attenuated by CaSR blockade. CONCLUSIONS: l-Phe reduced food intake, stimulated GLP-1 and PYY release, and reduced plasma ghrelin in rodents. Our data provide evidence that the anorectic effects of l-Phe are mediated via the CaSR, and suggest that l-Phe and the CaSR system in the GI tract may have therapeutic utility in the treatment of obesity and diabetes. Further work is required to determine the physiological role of the CaSR in protein sensing in the gut, and the role of this system in humans.

An evaluation of the feasibility and validity of a patient-administered malnutrition universal screening tool ('MUST') compared to healthcare professional screening in an inflammatory bowel disease (IBD) outpatient clinic.

BACKGROUND: Malnutrition is common in inflammatory bowel disease (IBD) and is associated with poor health outcomes. Despite this, screening for malnutrition in the outpatient-setting is not routine and research in the area is limited. The present study aimed to evaluate whether agreement between malnutrition screening completed by patients and healthcare professionals (HCPs) could be achieved by comparing patient self-administered 'MUST' ('MUST'-P) with HCP administered 'MUST' ('MUST'-HCP) in a single tertiary IBD outpatient clinic. METHODS: We conducted a feasibility and validity study on adult outpatients with IBD. We collected anthropometric, nutritional and clinical data from patients. All patients completed 'MUST'-P using a self-administered questionnaire, followed by 'MUST'-HCP. 'MUST'-P was timed and feedback on ease-of-use was obtained. The risk of malnutrition was classified as low (score = 0), medium (score = 1) and high (score ≥ 2) and agreement was tested using kappa statistics (κ). RESULTS: Eighty patients were recruited (Crohn's disease: n = 49, ulcerative colitis: n = 29, unclassified: n = 2), with a mean (SD) age of 39.9 (15.1) years (51.2% were males). Seventy-one (92%) of patients found 'MUST'-P either easy or very easy. The mean (SD) time to complete 'MUST'-P was 3.1  (1.8) min (range 1-10 min). Sixty-eight (85%) of patients were at low risk of malnutrition when screened by the HCP. There was moderate agreement (κ = 0.486, P < 0.001) between 'MUST'-P and 'MUST'-HCP, with 100% agreement in scoring for medium- and high-risk categories. CONCLUSIONS: The results of the present study suggests that self-screening using 'MUST' could be effectively used in an IBD outpatient clinic to identify those at medium and high risk of malnutrition. The patient friendly version of 'MUST' ('MUST'-P) was considered quick and easy to use by patients. Implementation of self-screening with 'MUST' could improve the nutritional management of IBD patients.

Novel circulating placental markers prokineticin-1, soluble fms-like tyrosine kinase-1, soluble endoglin and placental growth factor and association with late miscarriage.

STUDY QUESTION: Are novel circulating placental markers prokineticin-1 (PK-1), soluble fms-like tyrosine kinase-1 (sFlt-1), soluble endoglin (sEng) and placental growth factor (PlGF) associated with late miscarriage in asymptomatic first trimester pregnant women? SUMMARY ANSWER: Increased serum sFlt-1 or PlGF, but not sEng or PK-1, were significantly associated with reduced miscarriage risk after adjustment for age, BMI, gestational age, smoking and blood pressure. WHAT IS KNOWN ALREADY: Abnormal placental development is observed in two-thirds of miscarriages. Identifying women at high risk of late miscarriage could help diagnose potentially treatable causes of miscarriage such as infection, thrombosis or immunological disease. Recently, the circulating placental markers PK-1, sFlt-1, sEng and PlGF have been identified; however, it is not known if circulating levels of these markers are associated with late miscarriage. STUDY DESIGN, SIZE, DURATION: A single-centre observational cohort study with prospectively collected data was carried out at a tertiary care centre 2010-2012, in 993 asymptomatic pregnant women. Plasma PK-1, and serum sEng, sFlt-1 and PlGF were measured once in each patient during the antenatal booking visit, and pregnancy outcome was monitored prospectively. Less than 1% of patients were lost to follow-up. Multiples of median (MOM) levels were calculated to adjust for gestational age. PARTICIPANTS/MATERIALS, SETTING, METHODS: Nine-hundred and ninety-three asymptomatic pregnant women attending antenatal clinic for a routine booking antenatal appointment were recruited to the study, of whom 12 were lost to follow-up and excluded from analysis. Of the cohort, 50 of the remaining 981 women suffered late miscarriage. MAIN RESULTS AND THE ROLE OF CHANCE: Gestation-adjusted sEng, sFlt-1 and PlGF levels were 11% (P < 0.01), 36% (P < 0.001) and 30% (P < 0.001), respectively, lower in women who later suffered miscarriage compared with unaffected pregnancies, while PK-1 did not differ significantly. Logistic regression modelling suggested that increased sFlt-1 (odds ratio (OR) 0.15 95% confidence interval [0.08-0.26], P = 0.0001) and PlGF (OR 0.02 [0.01-0.05], P = 0.0001), but not sEng, were associated with reduced miscarriage risk after adjustment for age, BMI, gestational age, smoking and blood pressure. The combination of sFlt-1 and PlGF did not improve the diagnostic accuracy beyond the use of sFlt-1. LIMITATIONS, REASONS FOR CAUTION: First trimester levels of sFlt-1 and PlGF, but not sEng or PK-1, were associated with late miscarriage risk in asymptomatic women. However, a new prospective study is now required to investigate the utility of these markers to predict early (<10 weeks) and late miscarriage, as well as to predict other complications of pregnancy. WIDER IMPLICATIONS OF THE FINDINGS: Our data suggest that circulating sFlt-1 and PlGF, but not sEng or PK-1, are independently associated with late miscarriage risk in asymptomatic pregnant women attending their antenatal visit. Therefore, sFlt-1 and PlGF may represent novel markers of placental viability. These data further our understanding of placental function, and have important potential implications for utilizing novel hormonal markers to detect adverse clinical outcomes during pregnancy. STUDY FUNDING/COMPETING INTERESTS: The authors have no competing interests. The Section of Investigative Medicine is funded by grants from the MRC, BBSRC, NIHR, an Integrative Mammalian Biology (IMB) Capacity Building Award, an FP7-HEALTH-2009-241592 EuroCHIP grant and is supported by the NIHR Imperial Biomedical Research Centre Funding Scheme. This project was funded by an NIHR grant (reference: CDF-2009-02-05). The following authors are also funded as follows: CNJ is supported by an NIHR Clinical Lectureship and AMS/ Wellcome Starter Grant for Clinical Lecturers. AA and ANC are supported by NIHR academic clinical lectureships. CI-E is supported by an Imperial College Healthcare NHS Trust Charity Research Fellowship. WSD is supported by an NIHR Career Development Fellowship. TRIAL REGISTRATION NUMBER: Q0406/80.

Glucagon increases energy expenditure independently of brown adipose tissue activation in humans.

AIMS: To investigate, for a given energy expenditure (EE) rise, the differential effects of glucagon infusion and cold exposure on brown adipose tissue (BAT) activation in humans. METHODS: Indirect calorimetry and supraclavicular thermography was performed in 11 healthy male volunteers before and after: cold exposure; glucagon infusion (at 23 °C); and vehicle infusion (at 23 °C). All volunteers underwent (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET)/CT scanning with cold exposure. Subjects with cold-induced BAT activation on (18)F-FDG PET/CT (n = 8) underwent a randomly allocated second (18)F-FDG PET/CT scan (at 23 °C), either with glucagon infusion (n = 4) or vehicle infusion (n = 4). RESULTS: We observed that EE increased by 14% after cold exposure and by 15% after glucagon infusion (50 ng/kg/min; p < 0.05 vs control for both). Cold exposure produced an increase in neck temperature (+0.44 °C; p < 0.001 vs control), but glucagon infusion did not alter neck temperature. In subjects with a cold-induced increase in the metabolic activity of supraclavicular BAT on (18)F-FDG PET/CT, a significant rise in the metabolic activity of BAT after glucagon infusion was not detected. Cold exposure increased sympathetic activation, as measured by circulating norepinephrine levels, but glucagon infusion did not. CONCLUSIONS: Glucagon increases EE by a similar magnitude compared with cold activation, but independently of BAT thermogenesis. This finding is of importance for the development of safe treatments for obesity through upregulation of EE.

L-arginine promotes gut hormone release and reduces food intake in rodents.

AIMS: To investigate the anorectic effect of L-arginine (L-Arg) in rodents. METHODS: We investigated the effects of L-Arg on food intake, and the role of the anorectic gut hormones glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), the G-protein-coupled receptor family C group 6 member A (GPRC6A) and the vagus nerve in mediating these effects in rodents. RESULTS: Oral gavage of L-Arg reduced food intake in rodents, and chronically reduced cumulative food intake in diet-induced obese mice. Lack of the GPRC6A in mice and subdiaphragmatic vagal deafferentation in rats did not influence these anorectic effects. L-Arg stimulated GLP-1 and PYY release in vitro and in vivo. Pharmacological blockade of GLP-1 and PYY receptors did not influence the anorectic effect of L-Arg. L-Arg-mediated PYY release modulated net ion transport across the gut mucosa. Intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) administration of L-Arg suppressed food intake in rats. CONCLUSIONS: L-Arg reduced food intake and stimulated gut hormone release in rodents. The anorectic effect of L-Arg is unlikely to be mediated by GLP-1 and PYY, does not require GPRC6A signalling and is not mediated via the vagus. I.c.v. and i.p. administration of L-Arg suppressed food intake in rats, suggesting that L-Arg may act on the brain to influence food intake. Further work is required to determine the mechanisms by which L-Arg suppresses food intake and its utility in the treatment of obesity.

The short chain fatty acid propionate stimulates GLP-1 and PYY secretion via free fatty acid receptor 2 in rodents.

BACKGROUND AND OBJECTIVES: The gut hormones peptide YY (PYY) and glucagon-like peptide 1 (GLP-1) acutely suppress appetite. The short chain fatty acid (SCFA) receptor, free fatty acid receptor 2 (FFA2) is present on colonic enteroendocrine L cells, and a role has been suggested for SCFAs in appetite regulation. Here, we characterise the in vitro and in vivo effects of colonic propionate on PYY and GLP-1 release in rodents, and investigate the role of FFA2 in mediating these effects using FFA2 knockout mice. METHODS: We used Wistar rats, C57BL6 mice and free fatty acid receptor 2 knockout (FFA(-/-)) mice on a C57BL6 background to explore the impact of the SCFA propionate on PYY and GLP-1 release. Isolated colonic crypt cultures were used to assess the effects of propionate on gut hormone release in vitro. We subsequently developed an in vivo technique to assess gut hormone release into the portal vein following colonic infusion of propionate. RESULTS: Propionate stimulated the secretion of both PYY and GLP-1 from wild-type primary murine colonic crypt cultures. This effect was significantly attenuated in cultures from FFA2(-/-) mice. Intra-colonic infusion of propionate elevated PYY and GLP-1 levels in jugular vein plasma in rats and in portal vein plasma in both rats and mice. However, propionate did not significantly stimulate gut hormone release in FFA2(-/-) mice. CONCLUSIONS: Intra-colonic administration of propionate stimulates the concurrent release of both GLP-1 and PYY in rats and mice. These data demonstrate that FFA2 deficiency impairs SCFA-induced gut hormone secretion both in vitro and in vivo.

L-cysteine suppresses ghrelin and reduces appetite in rodents and humans.

BACKGROUND: High-protein diets promote weight loss and subsequent weight maintenance, but are difficult to adhere to. The mechanisms by which protein exerts these effects remain unclear. However, the amino acids produced by protein digestion may have a role in driving protein-induced satiety. METHODS: We tested the effects of a range of amino acids on food intake in rodents and identified l-cysteine as the most anorexigenic. Using rodents we further studied the effect of l-cysteine on food intake, behaviour and energy expenditure. We proceeded to investigate its effect on neuronal activation in the hypothalamus and brainstem before investigating its effect on gastric emptying and gut hormone release. The effect of l-cysteine on appetite scores and gut hormone release was then investigated in humans. RESULTS: l-Cysteine dose-dependently decreased food intake in both rats and mice following oral gavage and intraperitoneal administration. This effect did not appear to be secondary to behavioural or aversive side effects. l-Cysteine increased neuronal activation in the area postrema and delayed gastric emptying. It suppressed plasma acyl ghrelin levels and did not reduce food intake in transgenic ghrelin-overexpressing mice. Repeated l-cysteine administration decreased food intake in rats and obese mice. l-Cysteine reduced hunger and plasma acyl ghrelin levels in humans. CONCLUSIONS: Further work is required to determine the chronic effect of l-cysteine in rodents and humans on appetite and body weight, and whether l-cysteine contributes towards protein-induced satiety.

Direct comparison of the effects of intravenous kisspeptin-10, kisspeptin-54 and GnRH on gonadotrophin secretion in healthy men.

STUDY QUESTION: How potently does the novel hypothalamic stimulator of reproduction, kisspeptin, increase gonadotrophin secretion when compared with GnRH in healthy men? SUMMARY ANSWER: At the doses tested, intravenous administration of either of two major kisspeptin isoforms, kisspeptin-10 and -54, was associated with similar levels of gonadotrophin secretion in healthy men; however, GnRH was more potent when compared with either kisspeptin isoform. WHAT IS KNOWN ALREADY: Kisspeptin-10 and -54 are naturally occurring hormones in the kisspeptin peptide family which potently stimulates endogenous GnRH secretion from the hypothalamus, so have the potential to treat patients with reproductive disorders. Rodent studies suggest that kisspeptin-54 is more potent when compared with kisspepitn-10; however, their effects have not previously been directly compared in humans, or compared with direct pituitary stimulation of gonadotrophin secretion using GnRH. STUDY DESIGN, SIZE AND DURATION: A single-blinded placebo controlled physiological study was performed from January to December 2013. Local ethical approval was granted, and five participants were recruited to each dosing group. PARTICIPANTS/MATERIALS, SETTING, METHODS: Healthy men were administered vehicle, kisspeptin-10, kisspeptin-54 and GnRH intravenously for 3 h on different study days. Each hormone was administered at 0.1, 0.3 and 1.0 nmol/kg/h doses (n = 5 subjects per group). Regular blood sampling was conducted throughout the study to measure LH and FSH. Study visits were conducted at least a week apart. MAIN RESULTS AND THE ROLE OF CHANCE: Serum LH and FSH levels were ∼3-fold higher during GnRH infusion when compared with kisspeptin-10 and ∼2-fold higher when compared with kisspeptin-54 [mean area under the curve serum LH during infusion (in hours times international units per litre, h.IU/l): 10.81 ± 1.73, 1.0 nmol/kg/h kisspeptin-10; 14.43 ± 1.27, 1.0 nmol/kg/h kisspeptin-54; 34.06 ± 5.18, 1.0 nmol/kg/h GnRH, P < 0.001 versus kisspeptin-10, P < 0.01 versus kisspeptin-54]. LIMITATIONS, REASONS FOR CAUTION: This study had a small sample size. WIDER IMPLICATIONS OF THE FINDINGS: Kisspeptin offers a novel means of stimulating the reproductive axis. Our data suggest that kisspeptin stimulates gonadotrophin secretion less potently when compared with GnRH; however, kisspeptin may stimulate gonadotrophins in a more physiological manner when compared with current therapies. Kisspeptin is emerging as a future therapeutic agent, so it is important to establish which kisspeptin hormones could be used to treat patients with infertility. Results of this study suggest that either isoform has similar effects on reproductive hormone secretion in healthy men when administered intravenously. STUDY FUNDING/COMPETING INTERESTS: This work is funded by grants from the MRC and NIHR and is supported by the NIHR Imperial Biomedical Research Centre Funding Scheme. C.N.J. is supported by an NIHR Clinical Lectureship. A.A. is supported by Wellcome Trust Research Training Fellowships. A.N.C. is supported by Wellcome Trust Translational Medicine Training Fellowship. W.S.D. is supported by an NIHR Career Development Fellowship.

Portal hypertension: pathophysiology, diagnosis and management.

Portal hypertension is an important complication of liver disease. As a result of elevated pressures within the portal vein several complications can arise, including the development of oesophageal and gastric varices, ascites, hepatic encephalopathy as well as complications secondary to circulatory dysfunction, such as hepatorenal syndrome, portopulmonary syndrome and hepatopulmonary syndrome. This review outlines the pathogenesis and diagnosis of portal hypertension and outlines the management of these various important clinical sequelae. The management of oesophageal and gastric varices is particularly important, and both the emergency management together with prophylactic management of this condition are described.

Seasonal recurrence of food bolus obstruction in eosinophilic esophagitis.

BACKGROUND: Eosinophilic esophagitis (EoE) is a newly recognised condition that is apparently increasing in prevalence, and the aetiology is poorly understood. The role of aeroallergens in EoE is controversial, given the success of dietary therapy. Massive aeroallergen exposure leading to food bolus obstruction events (FBOE) has been described, and the diagnosis of EoE by esophageal biopsy noted to be more common in the pollen season according to previous case series. AIM: To determine if a seasonal variation and a geographical variation occurred in EoE presenting as FBOE in adults, and to track the prevalence of FBOE and EoE over time. METHOD: A retrospective case-control study analysis was performed from January 2002 to January 2012 to identify all FBOE in adults presenting to five tertiary hospitals in Melbourne, Australia. Endoscopy, histopathological reports, case notes and blood tests were examined, and postcodes recorded. Records of pollen counts were obtained. Cases were defined according to esophageal biopsy and grouped based on month of diagnosis. All other causes of FBOE served as controls. RESULTS: One thousand, one hundred and thirty-two FBOE were identified. Biopsies were only performed in 278 of these cases, and 85 patients were found to have EoE after biopsy. Patients with EoE were younger (mean age 38 years, range 18-72) compared with those with alternative diagnosis (mean age 64.4 range 22-92), more likely to be male (M : F = 4:1 compared with 1.68:1 ) and had a higher eosinophil count in venous blood. Overall no seasonality was demonstrated in FBOE secondary to any diagnosis, although the six cases of recurrent FBOE secondary to EoE mainly occurred in the grass pollen season in subsequent years. FBOE cases were evenly distributed throughout metropolitan Melbourne irrespective of population density. EoE as a percentage of FBOE increased over time. CONCLUSION: Seasonal aeroallergens may be important for a subgroup of patients with EoE presenting as recurrent FBOE. Esophageal biopsies are performed in a minority of patients, representing a significant departure from ideal management and contributing to recurrent unnecessary FBOE. EoE is an increasingly important cause of FBOE.

Can Bayliss and Starling gut hormones cure a worldwide pandemic?

Bayliss and Starling first coined the term 'hormone' with reference to secretin, a substance they found that was produced by the gut, but released into the blood stream to act at a distance. The intestine is now known as the largest endocrine organ in the body, and it produces numerous hormones with a wide range of functions. These include controlling appetite and energy homeostasis. Obesity is one of the greatest health threats facing the world today. At present, the only successful treatment is surgery. Bariatric procedures such as the Roux-en-Y bypass work by elevating gut hormones that induce satiety. Significant research has gone into producing versions of these hormones that can be delivered therapeutically to treat obesity. This review looks at the role of gut hormones in obesity, and the development of gut hormone-derived obesity treatments.

Intra-islet glucagon signalling regulates beta-cell connectivity, first-phase insulin secretion and glucose homoeostasis.

OBJECTIVE: Type 2 diabetes (T2D) is characterised by the loss of first-phase insulin secretion. We studied mice with ß-cell selective loss of the glucagon receptor (Gcgrfl/fl X Ins-1Cre), to investigate the role of intra-islet glucagon receptor (GCGR) signalling on pan-islet [Ca2+]I activity and insulin secretion. METHODS: Metabolic profiling was conducted on Gcgrß-cell-/- and littermate controls. Crossing with GCaMP6f (STOP flox) animals further allowed for ß-cell specific expression of a fluorescent calcium indicator. These islets were functionally imaged in vitro and in vivo. Wild-type mice were transplanted with islets expressing GCaMP6f in ß-cells into the anterior eye chamber and placed on a high fat diet. Part of the cohort received a glucagon analogue (GCG-analogue) for 40 days and the control group were fed to achieve weight matching. Calcium imaging was performed regularly during the development of hyperglycaemia and in response to GCG-analogue treatment. RESULTS: Gcgrß-cell-/- mice exhibited higher glucose levels following intraperitoneal glucose challenge (control 12.7 mmol/L ± 0.6 vs. Gcgrß-cell-/- 15.4 mmol/L ± 0.0 at 15 min, p = 0.002); fasting glycaemia was not different to controls. In vitro, Gcgrß-cell-/- islets showed profound loss of pan-islet [Ca2+]I waves in response to glucose which was only partially rescued in vivo. Diet induced obesity and hyperglycaemia also resulted in a loss of co-ordinated [Ca2+]I waves in transplanted islets. This was reversed with GCG-analogue treatment, independently of weight-loss (n = 8). CONCLUSION: These data provide novel evidence for the role of intra-islet GCGR signalling in sustaining synchronised [Ca2+]I waves and support a possible therapeutic role for glucagonergic agents to restore the insulin secretory capacity lost in T2D.

The regulation of food intake by the gut-brain axis: implications for obesity.

Our understanding of the regulation of appetite has improved considerably over the last few decades. Recent work, stimulated by efforts aimed at curbing the current obesity epidemic, has unravelled some of the complex pathways regulating energy homeostasis. Key factors to this progress have been the discovery of leptin and the neuronal circuitry involved in mediating its effects, as well as the identification of gut hormones that have important physiological roles relating to energy homeostasis. Despite these advances in research, there are currently no effective treatments for the growing problem of obesity. In this article, we summarise the regulatory pathways controlling appetite with a special focus on gut hormones. We detail how recent findings have contributed to our knowledge regarding the pathogenesis and treatment of common obesity. A number of barriers still need to be overcome to develop safe and effective anti-obesity treatments. We outline problems highlighted by historical failures and discuss the potential of augmenting natural satiety signals, such as gut hormones, to treat obesity.

Glucagon and GLP-1 inhibit food intake and increase c-fos expression in similar appetite regulating centres in the brainstem and amygdala.

BACKGROUND: Glucagon and glucagon-like peptide-1 (GLP-1) are evolutionarily related anorectic hormones. Glucagon also increases energy expenditure. The combination of glucagon and GLP-1 could cause weight loss through a simultaneous reduction in food intake and increased energy expenditure. However, the effect of combined administration of glucagon and GLP-1 on food intake and neuronal activation has not previously been studied. Furthermore, the effect of glucagon on neuronal activation in appetite regulating centres has not been assessed. Characterisation of the effects of glucagon when administered singly and in combination with GLP-1 on neuronal activation will be important for determining the mechanism of action of related potential antiobesity therapies. OBJECTIVES: To investigate the effects of peripherally administered GLP-1 and glucagon on food intake, neuronal activation and blood glucose in mice when administered individually and in combination. METHODOLOGY: Food intake, blood glucose and c-fos expression in the hypothalamus, amygdala and brainstem were measured in response to GLP-1 and glucagon, alone and in combination. RESULTS: Peripherally administered GLP-1 and glucagon decreased food intake and increased c-fos expression in the brainstem and amygdala. Doses of GLP-1 and glucagon that individually did not significantly affect feeding, in combination were anorectic and stimulated neuronal activation in the area postrema (AP) and central nucleus of the amygdala. Combined administration of GLP-1 and glucagon prevented the acute hyperglycemic effect of glucagon alone. CONCLUSION: Anorectic doses of glucagon and GLP-1 induced similar patterns of c-fos expression. Combined administration of low dose GLP-1 and glucagon inhibited food intake and induced c-fos expression in the AP and amygdala. The combination of both hormones may offer the opportunity to utilise the beneficial effects of reduced food intake and increased energy expenditure, and may therefore be a potential treatment for obesity.

A single injection of kisspeptin-54 temporarily increases luteinizing hormone pulsatility in healthy women.

BACKGROUND: Kisspeptin is a novel hypothalamic peptide which stimulates endogenous gonadotrophin releasing hormone (GnRH) secretion. A single subcutaneous bolus injection of kisspeptin-54 increases circulating luteinizing hormone (LH) levels in women, but its acute effects on LH pulsatility are not known. AIMS: To investigate the effects of a single subcutaneous (sc) injection of kisspeptin-54 administration on LH pulsatility in healthy female volunteers. METHODS: Six healthy female adult volunteers underwent 10-minute blood sampling for serum LH measurement for 8 h during the follicular phase of menstrual cycle. Sc bolus injection of saline or kisspeptin-54 (0·15, 0·30 or 0·60 nmol/kg) was administered 4 h after commencing the study. A previously described, blinded deconvolution method was used to detect LH pulses. RESULTS: Mean number of LH pulses was increased significantly following 0·30 and 0·60 nmol/kg kisspeptin-54 when compared with saline (mean increase in number of LH pulses per 4 h, following injection: -0·17 ± 0·54, saline; +2·33 ± 0·56, 0·30 nmol/kg kisspeptin-54, P < 0·05 vs saline; +2·33 ± 0·80, 0·60 nmol/kg kisspeptin-54, P < 0·05 vs saline). LH pulse secretory mass increased following injection of 0·60 nmol/kg in five of six subjects, but the mean change in all subjects was non-significant when compared with saline (mean increase in pulse secretory mass in IU/l following injection: +0·35 ± 0·40, saline; +2·61 ± 1·17, 0·60 nmol/kg kisspeptin-54, P = 0·10 vs saline). CONCLUSIONS: A single injection of kisspeptin-54 temporarily stimulates the number of LH pulses in healthy women. Further studies are required to investigate the therapeutic potential of kisspeptin-54 injection to restore LH pulsatility in patients with reproductive disorders caused by impaired GnRH secretion.

Hepcidin levels in diabetes mellitus and polycystic ovary syndrome.

AIM: Increased body iron is associated with insulin resistance. Hepcidin is the key hormone that negatively regulates iron homeostasis. We hypothesized that individuals with insulin resistance have inadequate hepcidin levels for their iron load. METHODS: Serum concentrations of the active form of hepcidin (hepcidin-25) and hepcidin:ferritin ratio were evaluated in participants with Type 2 diabetes (n = 33, control subjects matched for age, gender and BMI, n = 33) and participants with polycystic ovary syndrome (n = 27, control subjects matched for age and BMI, n = 16). To investigate whether any changes observed were associated with insulin resistance rather than insulin deficiency or hyperglycaemia per se, the same measurements were made in participants with Type 1 diabetes (n = 28, control subjects matched for age, gender and BMI, n = 30). Finally, the relationship between homeostasis model assessment of insulin resistance and serum hepcidin:ferritin ratio was explored in overweight or obese participants without diabetes (n = 16). RESULTS: Participants with Type 2 diabetes had significantly lower hepcidin and hepcidin:ferritin ratio than control subjects (P < 0.05 and P < 0.01, respectively). Participants with polycystic ovary syndrome had a significantly lower hepcidin:ferritin ratio than control subjects (P < 0.05). There was no significant difference in hepcidin or hepcidin:ferritin ratio between participants with Type 1 diabetes and control subjects (P = 0.88 and P = 0.94). Serum hepcidin:ferritin ratio inversely correlated with homeostasis model assessment of insulin resistance (r = -0.59, P < 0.05). CONCLUSION: Insulin resistance, but not insulin deficiency or hyperglycaemia per se, is associated with inadequate hepcidin levels. Reduced hepcidin concentrations may cause increased body iron stores in insulin-resistant states.

Exogenous peptide YY3-36 and Exendin-4 further decrease food intake, whereas octreotide increases food intake in rats after Roux-en-Y gastric bypass.

BACKGROUND: Patients show an elevated postprandial satiety gut hormone release after Roux-en-Y Gastric bypass (gastric bypass). The altered gut hormone response appears to have a prominent role in the reduction of appetite and body weight (BW) after gastric bypass. Patients with insufficient BW loss after gastric bypass have an attenuated postprandial gut hormone response in comparison with patients who lost an adequate amount of BW. The effects of additional gut hormone administration after gastric bypass are unknown. METHODS: The effects of peripheral administration of peptide YY3-36 (PYY3-36; 300 nmol kg(-1)), glucagon-like peptide-1 (GLP-1) analogue Exendin-4 (20 nmol kg(-1)) and somatostatin analogue octreotide (10 µg kg(-1)) on feeding and BW were evaluated in rats after gastric bypass. RESULTS: Gastric bypass rats weighed (P<0.01) and ate less on postoperative day 5 (P<0.001) and thereafter, whereas postprandial plasma PYY and GLP-1 levels were higher compared with sham-operated controls (P<0.001). Administration of both PYY3-36 and Exendin-4 led to a further decrease in food intake in bypass rats compared with saline treatment (P=0.02 and P<0.0001, respectively). Similar reduction in food intake was observed in sham rats (P=0.02 and P<0.001, respectively). Exendin-4 treatment resulted in a significant BW loss in bypass (P=0.03) and sham rats (P=0.04). Subsequent treatment with octreotide led to an increase in food intake in bypass (P=0.007), but not in sham rats (P=0.87). CONCLUSION: Peripheral administration of PYY3-36 and Exendin-4 reduces short-term food intake, whereas octreotide increases short-term food intake in rats after gastric bypass. The endogenous gut hormone response after gastric bypass can thus potentially be further enhanced by additional exogenous therapy with pharmacological doses of gut hormones in patients with insufficient weight loss or weight regain after surgery.

CCK, PYY and PP: the control of energy balance.

The control of food intake consists of neural and hormonal signals between the gut and central nervous system (CNS). Gut hormones such as CCK, PYY and PP signal to important areas in the CNS involved in appetite regulation to terminate a meal. These hormones can act directly via the circulation and activate their respective receptors in the hypothalamus and brainstem. In addition, gut vagal afferents also exist, providing an alternative pathway through which gut hormones can communicate with higher centres through the brainstem. Animal and human studies have demonstrated that peripheral administration of certain gut hormones reduces food intake and leads to weight loss. Gut hormones are therefore potential targets in the development of novel treatments for obesity and analogue therapies are currently under investigation.