Antagonic effect of ghrelin and LEAP-2 on hepatic stellate cell activation and liver fibrosis in obesity-associated nonalcoholic fatty liver disease.

BACKGROUND: Growing evidence suggests the key role of ghrelin in the onset and progression of nonalcoholic fatty liver disease (NAFLD). The potential participation of ghrelin and the ghrelin receptor antagonist, LEAP-2, in the onset of liver fibrosis in patients with severe obesity and NAFLD through the regulation of TGF-ß1-induced hepatic stellate cell (HSC) activation was investigated. METHODS: Circulating (n = 179) and hepatic expression (n = 95) of ghrelin and LEAP-2 were measured in patients with severe obesity and available liver pathology analysis undergoing Roux-en-Y gastric bypass (RYGB). The effect of ghrelin isoforms and LEAP-2 on TGF-ß1-induced HSC activation, fibrogenic response, and contractile properties was evaluated in vitro in human LX-2 cells. RESULTS: Plasma and hepatic ghrelin were negatively associated, while LEAP-2 exhibited a positive association with liver fibrosis in patients with obesity and NAFLD. Six months after RYGB, hepatic function was improved and, although acylated ghrelin and LEAP-2 concentrations remained unchanged, both hormones were inversely related to post-surgical levels of profibrogenic factors TGF-ß1 and TIMP-1. Acylated ghrelin treatment reversed TGF-ß1-induced myofibroblast-like phenotype, collagen contractile properties, and the upregulation of factors involved in HSC activation and fibrogenesis via PI3K/Akt/mTOR pathway. Moreover, acylated ghrelin inhibited the mild HSC activation induced by LEAP-2. CONCLUSIONS: Ghrelin is an anti-fibrogenic factor blocking HSC activation induced by the most potent fibrogenic cytokine, TGF-ß1, and LEAP-2. The imbalance between acylated ghrelin and ghrelin receptor antagonist LEAP-2 might contribute to maintain liver fibrosis in patients with obesity and NAFLD.

OSK-0028 in Patients With Esophageal Cancer Undergoing Esophagectomy: A Double-blind, Randomised Controlled Trial.

BACKGROUND/AIM: An excessive postoperative inflammatory response is correlated with the development of pneumonia and an unfavourable prognosis in patients undergoing esophagectomy for esophageal cancer. We assessed the influence of OSK-0028, a synthetic human ghrelin on inflammatory response and energy metabolism, on the postoperative course of patients following radical esophagectomy. PATIENTS AND METHODS: Esophageal cancer patients were randomly assigned to low-dose (LD; 0.25 µg/kg/h) or high-dose (HD; 0.5 µg/kg/h) intravenous OSK-0028 or placebo for 7 days after esophagectomy. The primary endpoint was serum interleukin-6 level on postoperative day (POD) 3. RESULTS: A total of 75 patients were enrolled (23 LD, 26 HD, 26 placebo). The median interleukin-6 levels on POD 3 were 40.95, 35.85, and 64.50 pg/ml in the placebo, LD, and HD groups, respectively, with no significant differences (p=0.78). Postoperative complications did not differ between groups. Bodyweight loss was significantly lower in patients receiving OSK-0028 than in those receiving placebo (-0.17% vs. 1.78%, p=0.043). CONCLUSION: Although OSK-0028 did not attenuate inflammatory response after esophagectomy, it prevented postoperative bodyweight loss.

Continuous ghrelin infusion attenuates the postoperative inflammatory response in patients with esophageal cancer.

PURPOSE: The aim of this study was to clarify whether ghrelin infusion is useful for suppressing inflammatory responses after esophagectomy. METHODS: A phase I study of ghrelin administration after esophagectomy was performed in 20 patients with esophageal cancer. The anti-inflammatory effect of ghrelin was compared with 20 consecutive patients who did not receive ghrelin infusion. Additionally, 10 patients with intermittent infusion for 10 days were compared with 10 patients with continuous infusion for 5 days. The primary endpoint was the duration of systemic inflammatory response syndrome (SIRS). Secondary endpoints included postoperative complications, serum C-reactive protein (CRP), interleukin-6 (IL-6), and growth hormone (GH) levels. RESULTS: No adverse events of ghrelin administration occurred. Patients with ghrelin infusion had higher plasma ghrelin levels on postoperative day (POD) 3 (p = 0.003) and shorter SIRS duration (p = 0.007) than patients without ghrelin infusion. Although SIRS duration was similar (p = 0.19), patients with continuous ghrelin infusion had significantly higher plasma ghrelin (p < 0.001) and GH levels (p = 0.002) on POD 3 than patients with intermittent ghrelin infusion. Serum CRP and IL-6 levels on POD 3 tended to be lower in the continuous infusion versus intermittent infusion group. CONCLUSIONS: Ghrelin was safely administered after esophagectomy and may reduce excess postoperative inflammatory responses. Continuous infusion is better for this purpose than intermittent infusion.

Ghrelin Aggravates Prostate Enlargement in Rats with Testosterone-Induced Benign Prostatic Hyperplasia, Stromal Cell Proliferation, and Smooth Muscle Contraction in Human Prostate Tissues.

Epidemiologic studies revealed a context between lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) and metabolic syndrome. However, molecular mechanisms underlying this relationship are largely unknown. Prostate enlargement and increased prostate smooth muscle tone are important factors in the pathophysiology of LUTS suggestive of BPH. In the present study, we studied effects of the metabolic hormone ghrelin on prostate enlargement in rats with experimentally induced BPH, growth of cultured stromal cells from human prostate (WPMY-1), and smooth muscle contraction of human prostate tissues. Ghrelin (20 nmol/kg daily, p.o., 2 weeks) increased prostate size in rats with testosterone-induced BPH. Microarray identified 114 ghrelin-upregulated genes (2-fold or more) in these prostates, with possible roles in growth, smooth muscle contraction, or metabolism. 12 genes were selected for further analyses. In human prostate tissues, mRNA levels of 11 of them correlated positively with ghrelin receptor (GHSR) expression, but only two with the degree of BPH. Accordingly, no correlation was evident between GHSR expression level and BPH in human prostate tissues. In WPMY-1 cells, the GHRS agonist MK0677 upregulated 11 of the selected genes. MK0677 induced proliferation of WPMY-1 cells, shown by EdU assay, colony formation, proliferation markers, flow cytometry, and viability. In myographic measurements, GHSR agonists enhanced contractions of human prostate strips. Together, ghrelin may aggravate prostate enlargement, stromal cell growth, and prostate smooth muscle contraction in BPH. Ghrelin may deteriorate urethral obstruction independently from BPH, qualifying the ghrelin system as an attractive new target to be tested for LUTS treatment in BPH.

Acute intravenous acyl ghrelin infusion induces thirst but does not affect sodium excretion: two randomized, double-blind, placebo-controlled crossover studies in hypopituitary patients.

OBJECTIVE: Acyl ghrelin, which is the endogenous ligand for the growth hormone secretagogue receptor, potently stimulates pituitary growth hormone release, and to some degree adrenocorticotropic hormone and prolactin. Ghrelin is also orexigenic and has recently been shown to stimulate renal sodium absorption in rodent models. Increased thirst sensation has been observed as a side effect of acyl ghrelin administration in some human studies. The objective of this clinical trial was to investigate the direct effects of acyl ghrelin on thirst sensation and sodium excretion in hypopituitary patients. DESIGN: Hypopituitary patients on stable replacement with hydrocortisone and growth hormone were investigated in two double-blind and placebo-controlled crossover studies. The patients received a 5-h intravenous infusion of acyl ghrelin (5 pmol/kg/min in the first study and 1 pmol/kg/min in the second study). Thirst sensation was measured on a Visual Analog Scale (VAS). In the second study plasma osmolality, vasopressin, copeptin, water intake, diuresis and urinary excretion of sodium and creatinine were measured. RESULTS: In the initial study, acyl ghrelin (5 pmol/kg/min) increased thirst sensation (time × treatment analysis of variance for the effect of acyl ghrelin infusion P = 0.003). In the second study acyl ghrelin (1 pmol/kg/min) also increased thirst (P = 0.04) but did not affect urinary excretion of either sodium or water. CONCLUSIONS: We demonstrate that acyl ghrelin infusion increases thirst sensation, without affecting sodium excretion or diuresis in human subjects.

Ghrelin for the management of cachexia associated with cancer.

BACKGROUND: Cancer sufferers are amongst the most malnourished of all the patient groups. Studies have shown that ghrelin, a gut hormone can be a potential therapeutic agent for cachexia (wasting syndrome) associated with cancer. A variety of mechanisms of action of ghrelin in people with cancer cachexia have been proposed. However, safety and efficacy of ghrelin for cancer-associated cachexia have not been systematically reviewed. The aim of this review was to assess whether ghrelin is associated with better food intake, body composition and survival than other options for adults with cancer cachexia. OBJECTIVES: To assess the efficacy and safety of ghrelin in improving food intake, body composition and survival in people with cachexia associated with cancer. SEARCH METHODS: We searched CENTRAL, MEDLINE and Embase without language restrictions up to July 2017. We also searched for ongoing studies in trials registers, performed handsearching, checked bibliographic references of relevant articles and contacted authors and experts in the field to seek potentially relevant research. We applied no restrictions on language, date, or publication status. SELECTION CRITERIA: We included randomised controlled (parallel-group or cross-over) trials comparing ghrelin (any formulation or route of administration) with placebo or an active comparator in adults (aged 18 years and over) who met any of the international criteria for cancer cachexia. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for eligibility. Two review authors then extracted data and assessed the risk of bias for individual studies using standard Cochrane methodology. For dichotomous variables, we planned to calculate risk ratio with 95% confidence intervals (CI) and for continuous data, we planned to calculate mean differences (MD) with 95% CI. We assessed the evidence using GRADE and created 'Summary of findings' tables. MAIN RESULTS: We screened 926 individual references and identified three studies that satisfied the inclusion criteria. Fifty-nine participants (37 men and 22 women) aged between 54 and 78 years were randomised initially, 47 participants completed the treatment. One study had a parallel design and two had a cross-over design. The studies included people with a variety of cancers and also differed in the dosage, route of administration, frequency and duration of treatment.One trial, which compared ghrelin with placebo, found that ghrelin improved food intake (very low-quality evidence) and had no adverse events (very low-quality evidence). Due to unavailability of data we were unable to report on comparisons for ghrelin versus no treatment or alternative experimental treatment modalities, or ghrelin in combination with other treatments or ghrelin analogues/ghrelin mimetics/ghrelin potentiators. Two studies compared a higher dose of ghrelin with a lower dose of ghrelin, however due to differences in study designs and great diversity in the treatment provided we did not pool the results. In both trials, food intake did not differ between participants on higher-dose and lower-dose ghrelin. None of the included studies assessed data on body weight. One study reported higher adverse events with a higher dose as compared to a lower dose of ghrelin.All studies were at high risk of attrition bias and bias for size of the study. Risk of bias in other domains was unclear or low.We rated the overall quality of the evidence for primary outcomes (food intake, body weight, adverse events) as very low. We downgraded the quality of the evidence due to lack of data, high or unclear risk of bias of the studies and small study size. AUTHORS' CONCLUSIONS: There is insufficient evidence to be able to support or refute the use of ghrelin in people with cancer cachexia. Adequately powered randomised controlled trials focusing on evaluation of safety and efficacy of ghrelin in people with cancer cachexia is warranted.

AZP-531, an unacylated ghrelin analog, improves food-related behavior in patients with Prader-Willi syndrome: A randomized placebo-controlled trial.

CONTEXT AND OBJECTIVE: Prader-Willi syndrome (PWS) is characterized by early-onset hyperphagia and increased circulating levels of the orexigenic Acylated Ghrelin (AG) hormone with a relative deficit of Unacylated Ghrelin (UAG). AZP-531, a first-in-class UAG analog, was shown to inhibit the orexigenic effect of AG in animals, to improve glycemic control and decrease body weight in humans. We aimed to investigate the safety and efficacy of AZP-531 in patients with PWS for whom no approved treatment for hyperphagia is currently available. METHODS AND DESIGN: Multi-center, randomized, double-blind, placebo-controlled trial. Forty-seven patients with genetically confirmed PWS and evidence of hyperphagia received daily subcutaneous injections of AZP-531 (3 and 4 mg for 50-70 kg and >70 kg body weight, respectively) or matching placebo for 14 days. Assessments included adverse events, vital signs, safety laboratory tests, the Hyperphagia Questionnaire (HQ), patient-reported appetite, body composition and glycemic measures. RESULTS: AZP-531 was well tolerated. There was a significant improvement with AZP-531 versus placebo in the mean total score, the 9-item score and the severity domain score of the HQ (p < .05). The highest reduction in the total and 9-item scores was observed in AZP-531 subjects with the highest hyperphagia score at baseline. Findings were supported by a reduction in appetite scores observed with AZP-531 only. Body weight did not change in both groups while a significant reduction in waist circumference and fat mass was observed only with AZP-531. AZP-531 significantly decreased post-prandial glucose levels in a baseline glucose dependent fashion. CONCLUSIONS: AZP-531 may constitute a new treatment strategy to improve hyperphagia and metabolic issues in patients with PWS. These findings support further investigation in longer-term clinical trials.

Metabolic responses to exogenous ghrelin in obesity and early after Roux-en-Y gastric bypass in humans.

AIMS: Ghrelin is a gastric-derived hormone that stimulates growth hormone (GH) secretion and has a multi-faceted role in the regulation of energy homeostasis, including glucose metabolism. Circulating ghrelin concentrations are modulated in response to nutritional status, but responses to ghrelin in altered metabolic states are poorly understood. We investigated the metabolic effects of ghrelin in obesity and early after Roux-en-Y gastric bypass (RYGB). MATERIALS AND METHODS: We assessed central and peripheral metabolic responses to acyl ghrelin infusion (1 pmol kg-1 min-1 ) in healthy, lean subjects (n = 9) and non-diabetic, obese subjects (n = 9) before and 2 weeks after RYGB. Central responses were assessed by GH and pancreatic polypeptide (surrogate for vagal activity) secretion. Peripheral responses were assessed by hepatic and skeletal muscle insulin sensitivity during a hyperinsulinaemic-euglycaemic clamp. RESULTS: Ghrelin-stimulated GH secretion was attenuated in obese subjects, but was restored by RYGB to a response similar to that of lean subjects. The heightened pancreatic polypeptide response to ghrelin infusion in the obese was attenuated after RYGB. Hepatic glucose production and hepatic insulin sensitivity were not altered by ghrelin infusion in RYGB subjects. Skeletal muscle insulin sensitivity was impaired to a similar degree in lean, obese and post-RYGB individuals in response to ghrelin infusion. CONCLUSIONS: These data suggest that obesity is characterized by abnormal central, but not peripheral, responsiveness to ghrelin that can be restored early after RYGB before significant weight loss. Further work is necessary to fully elucidate the role of ghrelin in the metabolic changes that occur in obesity and following RYGB.

Ghrelin administration for chronic respiratory failure: a randomized dose-comparison trial.

BACKGROUND: Repeated ghrelin administration leads to improvements in symptoms, muscle wasting and exercise tolerance in cachectic patients with pulmonary disease. We investigated the optimal ghrelin dose for underweight patients with chronic respiratory failure. METHODS: In this multicenter, randomized, dose-comparison exploratory study, 44 cachectic patients with chronic respiratory failure were randomly assigned pulmonary rehabilitation with intravenous twice-daily administration of 1 or 2 µg/kg ghrelin for 3 weeks. The primary endpoint was improvement in 6-min walking distance (6 MWD). The secondary endpoint was change in peak VO2. RESULTS: Twenty-one patients were assigned to the 1 µg/kg ghrelin group and 23 to the 2 µg/kg ghrelin group. Change from baseline 6 MWD after treatment was similar between groups(1 µg/kg: 53.9 m, 2 µg/kg: 53.9 m, p = 0.99). Mean change in peak VO2 was significantly greater in the 2 µg/kg group (63.1 ml/min) than in the 1 µg/kg group (-63.8 ml/min, p = 0.048). Food intake and lean body mass significantly increased in both groups, and the St. George Respiratory Questionnaire score, body weight, and body mass index were remarkably improved in only the 2 µg/kg group, although there was no significant difference between groups. No treatment-related serious events were reported for either group. CONCLUSION: Improvements in the oxygen uptake capacity were greater in patients receiving 2 µg/kg ghrelin twice daily for 3 weeks than in those receiving 1 µg/kg, although exercise tolerance was similar between groups at the end of the 3-week treatment period. Thus, a twice daily dose of 2 µg/kg ghrelin is recommended over 1 µg/kg ghrelin for patients with chronic respiratory failure and weight loss.

Clinical effects of ghrelin on gastrointestinal involvement in patients with systemic sclerosis.

The majority of patients with systemic sclerosis (SSc) have gastrointestinal (GI) tract involvement, but therapies using prokinetic agents are usually unsatisfactory. Ghrelin stimulates gastric motility in healthy human volunteers. In this study, we investigated whether ghrelin could improve gastric emptying in patients with gastrointestinal symptoms due to SSc. The study was performed in a randomized, double-blind, placebo-controlled crossover fashion on two occasions. Ten SSc patients with GI tract involvement received an infusion of either ghrelin (5.0 µg/kg) or saline, and gastric emptying rate was evaluated by ¹³C-acetic acid breath test. Gastric emptying was significantly accelerated by ghrelin infusion in patients with SSc (ghrelin vs. saline: 43.3 ± 11.4 min vs. 53.4 ± 5.4 min, P=0.03). No serious adverse effects were observed. Our results suggest that ghrelin might represent a new therapeutic approach for GI tract involvement in patients with SSc.

Short-term estradiol supplementation potentiates low-dose ghrelin action in the presence of GHRH or somatostatin in older women.

CONTEXT: Ghrelin is a potent gastric-derived GH-releasing peptide. How ghrelin interacts with sex steroids, GHRH, and somatostatin (SS) is not known. OBJECTIVE: Our objective was to test the hypotheses that ghrelin's interactions with GHRH (synergistic) and SS (disinhibitory) are ghrelin dose-dependent and amplified by estrogen. SUBJECTS, SETTING, AND DESIGN: Healthy postmenopausal women were treated with placebo (n=12) or 17ß-estradiol (E2) (n=12) at the Center for Translational Science Activities in a randomized double-blind prospective study. METHODS: Ghrelin dose-dependence was assessed by nonlinear curve fitting of the relationship between deconvolved GH secretory-burst mass and 5 randomly ordered ghrelin doses (0, 0.03, 0.135, 0.6, and 2.7 µg/kg bolus iv) during saline, GHRH, and SS infusion. RESULTS: Under placebo, neither GHRH nor SS altered the ED50 of ghrelin (range 0.64-0.67 µg/kg). Under E2 (median E2 88 pg/mL), the ED50 of ghrelin declined in the presence of GHRH to 0.52 µg/kg. In contrast, the efficacy of ghrelin rose markedly during GHRH vs saline exposure with and without E2: placebo and saline 52±1.0 vs GHRH 173±3.8 µg/L; and E2 and saline 56±0.90 vs GHRH 174±3.7 µg/L. Sensitivity to ghrelin was similar under all conditions. SUMMARY: Short-term E2 supplementation in postmenopausal women reduces the ED50 (increases the potency) of ghrelin when GHRH is present, without altering ghrelin efficacy (maximal effect) or hypothalamo-pituitary sensitivity (slope of dose response) to ghrelin. The data suggest possible physiological interactions among sex steroids (endogenous), ghrelin, and GHRH during E2 replacement in postmenopausal women.

Growth hormone axis and aging.

Growth hormone (GH) and/or ghrelin mimetics represent potential treatment and/or prevention options for musculoskeletal impairment associated with aging. Use of improvement in muscle function as an outcome in studies of GH and ghrelin mimetics is complicated by the lack of a standardized definition for clinically meaningful efficacy of this end point. Based on preliminary study results, the use of ghrelin mimetics may be more suitable for use in this age group than GH itself. There are still several unanswered questions related to the use of ghrelin mimetics in the elderly, which prevents recommendation for its use at the current time.

Physiologic concentrations of exogenously infused ghrelin reduces insulin secretion without affecting insulin sensitivity in healthy humans.

BACKGROUND: Infusion of ghrelin to supraphysiologic levels inhibits glucose-stimulated insulin secretion, reduces insulin sensitivity, and worsens glucose tolerance in humans. OBJECTIVE: The purpose of this study was to determine the effects of lower doses of ghrelin on insulin secretion and insulin sensitivity in healthy men and women. METHODS: Acyl ghrelin (0.2 and 0.6 nmol kg(-1) h(-1)) or saline was infused for 225 minutes in 16 healthy subjects on 3 separate occasions in randomized order. An i.v. glucose tolerance test was performed, and the insulin sensitivity index (SI) was derived from the minimal model. Insulin secretion was measured as the acute insulin response to glucose (AIRg) and the disposition index was computed as AIRg × SI. RESULTS: Ghrelin infusions at 0.2 and 0.6 nmol kg(-1) h(-1) raised steady-state plasma total ghrelin levels 2.2- and 6.1-fold above fasting concentrations. Neither dose of ghrelin altered fasting plasma insulin, glucose, or SI, but both doses reduced insulin secretion compared with the saline control, computed either as AIRg (384 ± 75 and 354 ± 65 vs 520 ± 110 pM · min [mean ± SEM], respectively; P < .01 for both low- and high-dose vs saline) or disposition index (2238 ± 421 and 2067 ± 396 vs 3339 ± 705, respectively; P < .02 for both comparisons). The high-dose ghrelin infusion also decreased glucose tolerance. CONCLUSIONS: Ghrelin infused to levels occurring in physiologic states such as starvation decreases insulin secretion without affecting insulin sensitivity. These findings are consistent with a role for endogenous ghrelin in the regulation of insulin secretion and suggest that ghrelin antagonism could improve ß-cell function.

Clinical review: The human experience with ghrelin administration.

CONTEXT: Ghrelin is an endogenous stimulator of GH and is implicated in a number of physiological processes. Clinical trials have been performed in a variety of patient populations, but there is no comprehensive review of the beneficial and adverse consequences of ghrelin administration to humans. EVIDENCE ACQUISITION: PubMed was utilized, and the reference list of each article was screened. We included 121 published articles in which ghrelin was administered to humans. EVIDENCE SYNTHESIS: Ghrelin has been administered as an infusion or a bolus in a variety of doses to 1850 study participants, including healthy participants and patients with obesity, prior gastrectomy, cancer, pituitary disease, diabetes mellitus, eating disorders, and other conditions. There is strong evidence that ghrelin stimulates appetite and increases circulating GH, ACTH, cortisol, prolactin, and glucose across varied patient populations. There is a paucity of evidence regarding the effects of ghrelin on LH, FSH, TSH, insulin, lipolysis, body composition, cardiac function, pulmonary function, the vasculature, and sleep. Adverse effects occurred in 20% of participants, with a predominance of flushing and gastric rumbles and a mild degree of severity. The few serious adverse events occurred in patients with advanced illness and were not clearly attributable to ghrelin. Route of administration may affect the pattern of adverse effects. CONCLUSIONS: Existing literature supports the short-term safety of ghrelin administration and its efficacy as an appetite stimulant in diverse patient populations. There is some evidence to suggest that ghrelin has wider ranging therapeutic effects, although these areas require further investigation.

Ghrelin counteracts salt-induced hypertension via promoting diuresis and renal nitric oxide production in Dahl rats.

Ghrelin is the endogenous ligand for the growth hormone-secretagogue receptor expressed in various tissues including the heart, blood vessels and kidney. This study sought to determine the effects of long-term treatment with ghrelin (10 nmol/kg, twice a day, intraperitoneally) on the hypertension induced by high salt (8.0% NaCl) diet in Dahl salt-sensitive hypertensive (DS) rats. Systolic blood pressure (SBP) was measured by a tail cuff method. During the treatment period for 3 weeks, high salt diet increased blood pressure compared to normal salt (0.3% NaCl) diet, and this hypertension was partly but significantly (P<0.01) attenuated by simultaneous treatment with ghrelin. Ghrelin significantly increased urine volume and tended to increase urine Na⁺ excretion. Furthermore, ghrelin increased urine nitric oxide (NO) excretion and tended to increase renal neuronal nitric oxide synthase (nNOS) mRNA expression. Ghrelin did not alter the plasma angiotensin II level and renin activity, nor urine catecholamine levels. Furthermore, ghrelin prevented the high salt-induced increases in heart thickness and plasma ANP mRNA expression. These results demonstrate that long-term ghrelin treatment counteracts salt-induced hypertension in DS rats primarily through diuretic action associated with increased renal NO production, thereby exerting cardio-protective effects.

Therapeutic potential of anamorelin, a novel, oral ghrelin mimetic, in patients with cancer-related cachexia: a multicenter, randomized, double-blind, crossover, pilot study.

PURPOSE: Cachexia in cancer adversely affects patients' perception of symptoms, well-being, and response to therapy, and shortens survival. Anamorelin, an oral mimetic of ghrelin, has been shown to increase body weight and anabolic hormone levels in healthy volunteers and is being investigated to treat cancer cachexia. METHODS: This multicenter, double-blind, placebo-controlled, crossover study evaluated the effects of anamorelin in 16 patients with different cancers and cachexia. Patients were randomly assigned to anamorelin 50 mg/day or placebo for 3 days. A 3- to 7-day washout period followed and then treatments were switched. Assessments included body weight, appetite, food intake, growth hormone (GH) levels, patient-reported symptom assessments (e.g., the Anderson Symptom Assessment Scale [ASAS] and also an inclusion criterion), and safety. RESULTS: Anamorelin significantly increased body weight compared with placebo (0.77 kg vs. -0.33 kg). Food intake increased compared with placebo, but not significantly. GH significantly increased at all time points (0.5-4 h postdose). Insulin-like growth factor-1 (IGF-1) significantly increased by 54.09 ng/mL with anamorelin treatment compared with -3.56 ng/mL for placebo; significant changes in insulin-like growth factor-binding protein 3 (IGFBP-3) were 0.75 µg/mL vs. -0.19 µg/mL, respectively. Patient-reported symptoms, including appetite as measured by ASAS, significantly improved with anamorelin (8.1 vs. 1.0 for placebo). Adverse events (AEs) in four patients were possibly or probably related to anamorelin: hyperglycemia (two patients), nausea (one patient), and dizziness (one patient). Most AEs were mild; no patients withdrew due to AEs. CONCLUSIONS: Anamorelin showed significant metabolic, clinical, and patient-rated effects in cancer cachexia. Further studies are warranted.

Implications of gastrointestinal hormones in the pathogenesis of obesity in prepubertal children.

BACKGROUND: There is a worsening high prevalence of global obesity. Special attention has been paid to the gut-endocrine system, represented by the regulators of appetite. In particular, it has been suggested that ghrelin ("hunger" peptide), and obestatin and glucagon-like peptide-1 (GLP-1) ("satiety" peptides) could play important roles in the pathogenesis of obesity. OBJECTIVES: The aims of this study were to compare fasting plasma ghrelin, obestatin, and GLP-1 levels between obese and nonobese prepubertal children, and to assess their relations with fatness indexes and insulin resistance (IR). SUBJECTS AND METHODS: Fifty-two prepubertal obese children and 22 controls were enrolled. Fasting levels of gastrointestinal hormones (ghrelin, obestatin, and GLP-1), glucose, and insulin were evaluated. IR was assessed using the homeostasis model assessment of IR (HOMA-IR) index. Analysis was performed by Mann-Whitney U-test, Kruskal-Wallis test, and Spearman's correlation. RESULTS: Obese prepubertal children and normal-weight controls had similar age distribution. Obese children were more insulin resistant when compared to controls (HOMA-IR: p < 0.01 ). GLP-1 levels were significantly lower in obese children than in controls (p < 0.01). Obestatin was significantly higher in obese than normal-weight children (p < 0.01), while ghrelin was not different. There was a negative correlation between GLP-1 and standard deviation score-body mass index (r = -0.36, p = 0.009) and between GLP-1 and waist circumference (r = -0.45, p = 0.001), while no association was observed with HOMA-IR. CONCLUSIONS: GLP-1 levels have been shown to be correlated with adiposity indexes, but not with HOMA-IR, suggesting that this hormone could play an important role in the early development of obesity.

Ghrelin treatment of cachectic patients with chronic obstructive pulmonary disease: a multicenter, randomized, double-blind, placebo-controlled trial.

BACKGROUND: Pulmonary cachexia is common in advanced chronic obstructive pulmonary disease (COPD), culminating in exercise intolerance and a poor prognosis. Ghrelin is a novel growth hormone (GH)-releasing peptide with GH-independent effects. The efficacy and safety of adding ghrelin to pulmonary rehabilitation (PR) in cachectic COPD patients were investigated. METHODOLOGY/PRINCIPAL FINDINGS: In a multicenter, randomized, double-blind, placebo-controlled trial, 33 cachectic COPD patients were randomly assigned PR with intravenous ghrelin (2 µg/kg) or placebo twice daily for 3 weeks in hospital. The primary outcomes were changes in 6-min walk distance (6-MWD) and the St. George Respiratory Questionnaire (SGRQ) score. Secondary outcomes included changes in the Medical Research Council (MRC) scale, and respiratory muscle strength. At pre-treatment, serum GH levels were increased from baseline levels by a single dose of ghrelin (mean change, +46.5 ng/ml; between-group p<0.0001), the effect of which continued during the 3-week treatment. In the ghrelin group, the mean change from pre-treatment in 6-MWD was improved at Week 3 (+40 m, within-group p = 0.033) and was maintained at Week 7 (+47 m, within-group p = 0.017), although the difference between ghrelin and placebo was not significant. At Week 7, the mean changes in SGRQ symptoms (between-group p = 0.026), in MRC (between-group p = 0.030), and in maximal expiratory pressure (MEP; between-group p = 0.015) were better in the ghrelin group than in the placebo group. Additionally, repeated-measures analysis of variance (ANOVA) indicated significant time course effects of ghrelin versus placebo in SGRQ symptoms (p = 0.049) and MEP (p = 0.021). Ghrelin treatment was well tolerated. CONCLUSIONS/SIGNIFICANCE: In cachectic COPD patients, with the safety profile, ghrelin administration provided improvements in symptoms and respiratory strength, despite the lack of a significant between-group difference in 6-MWD. TRIAL REGISTRATION: UMIN Clinical Trial Registry C000000061.

Effects of ghrelin on pulmonary NOD2 mRNA expression and NF-κB activation when protects against acute lung injury in rats challenged with cecal ligation and puncture.

BACKGROUND: Many studies have shown that ghrelin can down-regulate inflammatory cytokine expression via the inhibition of NF-κB activity and therefore, its administration to septic patients is considered beneficial. However, our knowledge of ghrelin's effects on the upstream activators of the NF-κB pathway, such as NOD2, is still limited. This study aimed to investigate the possible involvement of the NOD2 signaling pathway in the anti-inflammatory effects of ghrelin. METHODS: Twenty-four male SD rats received cecal ligation and puncture (CLP) or sham operation, followed by infusion of saline or ghrelin. The lungs were harvested 6h after CLP or sham operation and analyzed for lung histopathology, neutrophil infiltration, inflammatory cytokines (TNF-α, and IL-6), NOD2 mRNA expression, and activation of NF-κB. Furthermore, survival was recorded for ten days in additional groups of rats. RESULTS: Compared with sham group, neutrophil infiltration, TNF-α and IL-6 levels, NOD2 mRNA expression, as well as NF-κB activation in lungs from rats undergoing CLP were significantly increased. After the administration of ghrelin, all inflammatory parameters analyzed were lower than those without ghrelin following CLP. In addition, ghrelin improved survival after CLP. CONCLUSION: Our results indicate that in a CLP model of sepsis, the beneficial effects that ghrelin has on inflammatory outcomes are mediated at least in part through inhibition of NOD2 expression upstream of NF-κB.

Effects of ghrelin, growth hormone-releasing peptide-6, and growth hormone-releasing hormone on growth hormone, adrenocorticotropic hormone, and cortisol release in type 1 diabetes mellitus.

In type 1 diabetes mellitus (T1DM), growth hormone (GH) responses to provocative stimuli are normal or exaggerated, whereas the hypothalamic-pituitary-adrenal axis has been less studied. Ghrelin is a GH secretagogue that also increases adrenocorticotropic hormone (ACTH) and cortisol levels, similarly to GH-releasing peptide-6 (GHRP-6). Ghrelin's effects in patients with T1DM have not been evaluated. We therefore studied GH, ACTH, and cortisol responses to ghrelin and GHRP-6 in 9 patients with T1DM and 9 control subjects. The GH-releasing hormone (GHRH)-induced GH release was also evaluated. Mean fasting GH levels (micrograms per liter) were higher in T1DM (3.5 ± 1.2) than in controls (0.6 ± 0.3). In both groups, ghrelin-induced GH release was higher than that after GHRP-6 and GHRH. When analyzing Δ area under the curve (ΔAUC) GH values after ghrelin, GHRP-6, and GHRH, no significant differences were observed in T1DM compared with controls. There was a trend (P = .055) to higher mean basal cortisol values (micrograms per deciliter) in T1DM (11.7 ± 1.5) compared with controls (8.2 ± 0.8). No significant differences were seen in ΔAUC cortisol values in both groups after ghrelin and GHRP-6. Mean fasting ACTH values were similar in T1DM and controls. No differences were seen in ΔAUC ACTH levels in both groups after ghrelin and GHRP-6. In summary, patients with T1DM have normal GH responsiveness to ghrelin, GHRP-6, and GHRH. The ACTH and cortisol release after ghrelin and GHRP-6 is also similar to controls. Our results suggest that chronic hyperglycemia of T1DM does not interfere with GH-, ACTH-, and cortisol-releasing mechanisms stimulated by these peptides.