Ghrelin in chronic liver disease

Ghrelin regulating liver activity and its potential effects on liver fibrosis and Echinococcosis

Ghrelin widely exists in the central nervous system and peripheral organs, and has biological activities such as maintaining energy homeostasis, regulating lipid metabolism, cell proliferation, immune response, gastrointestinal physiological activities, cognition, memory, circadian rhythm and reward effects. In many benign liver diseases, it may play a hepatoprotective role against steatosis, chronic inflammation, oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress and apoptosis, and improve liver cell autophagy and immune response to improve disease progression. However, the role of Ghrelin in liver Echinococcosis is currently unclear. This review systematically summarizes the molecular mechanisms by which Ghrelin regulates liver growth metabolism, immune-inflammation, fibrogenesis, proliferation and apoptosis, as well as its protective effects in liver fibrosis diseases, and further proposes the role of Ghrelin in liver Echinococcosis infection. During the infectious process, it may promote the parasitism and survival of parasites on the host by improving the immune-inflammatory microenvironment and fibrosis state, thereby accelerating disease progression. However, there is currently a lack of targeted in vitro and in vivo experimental evidence for this viewpoint.

Molecular and cellular mechanisms underlying the hepatoprotective role of ghrelin against NAFLD progression

The underlying mechanisms for the development and progression of nonalcoholic fatty liver disease (NAFLD) are complex and multifactorial. Within the last years, experimental and clinical evidences support the role of ghrelin in the development of NAFLD. Ghrelin is a gut hormone that plays a major role in the short-term regulation of appetite and long-term regulation of adiposity. The liver constitutes a target for ghrelin, where this gut-derived peptide triggers intracellular pathways regulating lipid metabolism, inflammation, and fibrosis. Interestingly, circulating ghrelin levels are altered in patients with metabolic diseases, such as obesity, type 2 diabetes, and metabolic syndrome, which, in turn, are well-known risk factors for the pathogenesis of NAFLD. This review summarizes the molecular and cellular mechanisms involved in the hepatoprotective action of ghrelin, including the reduction of hepatocyte lipotoxicity via autophagy and fatty acid β-oxidation, mitochondrial dysfunction, endoplasmic reticulum stress and programmed cell death, the reversibility of the proinflammatory phenotype in Kupffer cells, and the inactivation of hepatic stellate cells. Together, the metabolic and inflammatory pathways regulated by ghrelin in the liver support its potential as a therapeutic target to prevent NAFLD in patients with metabolic disorders.

Role of the Ghrelin System in Colitis and Hepatitis as Risk Factors for Inflammatory-Related Cancers

It is not known exactly what leads to the development of colorectal cancer (CRC) and hepatocellular carcinoma (HCC), but there are specific risk factors that increase the probability of their occurrence. The unclear pathogenesis, too-late diagnosis, poor prognosis as a result of high recurrence and metastasis rates, and repeatedly ineffective therapy of both cancers continue to challenge both basic science and practical medicine. The ghrelin system, which is comprised of ghrelin and alternative peptides (e.g., obestatin), growth hormone secretagogue receptors (GHS-Rs), and ghrelin-O-acyl-transferase (GOAT), plays an important role in the physiology and pathology of the gastrointestinal (GI) tract. It promotes various physiological effects, including energy metabolism and amelioration of inflammation. The ghrelin system plays a role in the pathogenesis of inflammatory bowel diseases (IBDs), which are well known risk factors for the development of CRC, as well as inflammatory liver diseases which can trigger the development of HCC. Colitis-associated cancer serves as a prototype of inflammation-associated cancers. Little is known about the role of the ghrelin system in the mechanisms of transformation of chronic inflammation to low- and high-grade dysplasia, and, finally, to CRC. HCC is also associated with chronic inflammation and fibrosis arising from different etiologies, including alcoholic and nonalcoholic fatty liver diseases (NAFLD), and/or hepatitis B (HBV) and hepatitis C virus (HCV) infections. However, the exact role of ghrelin in the progression of the chronic inflammatory lesions into HCC is still unknown. The aim of this review is to summarize findings on the role of the ghrelin system in inflammatory bowel and liver diseases in order to better understand the impact of this system on the development of inflammatory-related cancers, namely CRC and HCC.

Protein Catabolism and the Dysregulation of Energy Intake-Related Hormones May Play a Major Role in the Worsening of Malnutrition in Hospitalized Cirrhotic Patients

Malnutrition in cirrhotic patients is extremely common and has a multifactorial aetiology, whose constitutive elements have not been completely elucidated yet. Protein depletion is particularly important and an imbalance of hormones regulating hunger and satiety may be an important additive factor. The diagnosis and treatment of malnutrition are extremely important since malnutrition is associated with higher complication rates and mortality. Our observational study aimed to study protein status and energy intake-related hormone levels in a cohort of hospitalized cirrhotic patients. We enrolled 50 hospitalized and clinically stable cirrhotic patients and assessed their nutritional status with anthropometric measurements and nitrogen balance. In a subgroup of 16 patients and 10 healthy controls, circulating ghrelin and leptin levels were studied. We observed that 60% of our patients were malnourished on the basis of the mid-arm muscle circumference values; the recorded daily protein intake was tendentially insufficient (mean protein intake of 0.7 ± 0.5 g protein/kg vs. recommended intake of 1.2–1.5 g of protein/kg/die). Cirrhotic patients had lower circulating levels of both ghrelin and leptin compared to healthy controls. In conclusion, hospitalized cirrhotic patients face a catabolic state and an imbalance in hormones regulating food intake and satiety, and these elements may play a major role in the genesis and/or the worsening of malnutrition.

Predictive and Diagnostic Value of Serum Adipokines in Pregnant Women with Intrahepatic Cholestasis

The objective of this study was to assess the value of serum leptin, adiponectin, apelin, and ghrelin as biomarkers for the prediction and diagnosis of intra-hepatic cholestasis (ICP). This prospective study included pregnant women in the third trimester of pregnancy: 63 with ICP, 48 and 15 of whom had mild and severe disease, respectively, and 32 as controls. ICP women had increased median levels of serum leptin, adiponectin, apelin, and ghrelin compared to the controls (p < 0.05). These biomarkers meaningfully changed regarding the severity of ICP: While leptin was reduced, apelin and ghrelin were increased, and adiponectin was increased somewhat. To predict and diagnose ICP, the predictive values of serum leptin, adiponectin, and apelin need to be accepted as comparable, with moderate to high sensitivity and specificity; however, the predictive value of serum ghrelin was somewhat lower. More research is needed to clarify the potential properties of adipokines to gain acceptance as a predictive or diagnostic biomarker for ICP.

Serum Ghrelin Concentration in Patients With Primary Biliary Cirrhosis (PBC)

INTRODUCTION

The appetite-modulating hormone ghrelin may have a role in the etiology of anorexia which is a serious concern in patients with primary biliary cirrhosis (PBC). This study aims to assess the difference in ghrelin level between cases of PBC and healthy controls matched for age and gender, and to evaluate the level of ghrelin in relation to clinical and laboratory findings among cases.

METHODS

Twenty patients with primary biliary cirrhosis and 30 healthy controls matched by gender and age were recruited. The severity of liver disease was determined using the Child-Pugh grading system. Clinical comorbidities such as a history of ascites, gastrointestinal bleeding, and encephalopathy were evaluated. A commercial enzyme-linked immunosorbent assay was used to measure total ghrelin.  Results: PBC cases had a significantly higher average level of ghrelin (2305.3 ± 639.4) pg/mL compared to controls (682 ± 197.3) pg/mL. Furthermore, the minimum reported level in cases was 1258 pg/mL compared to 326 pg/mL in controls, while the maximum level nearly tripled the control's maximum level. In PBC patients, plasma levels of total ghrelin showed a weak positive correlation with age, an inverse correlation with body mass index, and were not associated with gender. The level was significantly higher than those in the controls. Ghrelin was associated with the severity of cirrhosis. Levels of serum ghrelin were higher in patients with associated comorbidities such as a history of ascites, gastrointestinal bleeding, and encephalopathy.

CONCLUSIONS

Our study demonstrated elevated serum ghrelin levels in patients with primary biliary cirrhosis. Serum ghrelin was associated with the degree of severity and the presence of related comorbidities. Patients with primary biliary cirrhosis remain anorexic and catabolic despite elevated ghrelin levels, suggesting tissue resistance to this anabolic peptide which could be crucial to understanding anorexia and cachexia in primary biliary cirrhosis.

Ghrelin reverses ductular reaction and hepatic fibrosis in a rodent model of cholestasis

The orexigenic peptide ghrelin (Ghr) stimulates hunger signals in the hypothalamus via growth hormone secretagogue receptor (GHS-R1a). Gastric Ghr is synthetized as a preprohormone which is proteolytically cleaved, and acylated by a membrane-bound acyl transferase (MBOAT). Circulating Ghr is reduced in cholestatic injuries, however Ghr's role in cholestasis is poorly understood. We investigated Ghr's effects on biliary hyperplasia and hepatic fibrosis in Mdr2-knockout (Mdr2KO) mice, a recognized model of cholestasis. Serum, stomach and liver were collected from Mdr2KO and FVBN control mice treated with Ghr, des-octanoyl-ghrelin (DG) or vehicle. Mdr2KO mice had lower expression of Ghr and MBOAT in the stomach, and lower levels of circulating Ghr compared to WT-controls. Treatment of Mdr2KO mice with Ghr improved plasma transaminases, reduced biliary and fibrosis markers. In the liver, GHS-R1a mRNA was expressed predominantly in cholangiocytes. Ghr but not DG, decreased cell proliferation via AMPK activation in cholangiocytes in vitro. AMPK inhibitors prevented Ghr-induced FOXO1 nuclear translocation and negative regulation of cell proliferation. Ghr treatment reduced ductular reaction and hepatic fibrosis in Mdr2KO mice, regulating cholangiocyte proliferation via GHS-R1a, a G-protein coupled receptor which causes increased intracellular Ca2+ and activation of AMPK and FOXO1, maintaining a low rate of cholangiocyte proliferation.

Exploration of the role of serum ghrelin in the diagnosis and treatment of digestive tract malignancies

OBJECTIVE

The incidence of digestive tract malignancies (DTMs) is increasing, early diagnosis is limited, and treatment effects are unsatisfactory. DTMs express ghrelin, which might be involved in tumor formation and development; whether serum ghrelin can provide useful guidance remains unknown.

METHODS

Sera of healthy individuals were obtained from October 2017 through March 2018; serum samples from patients with gastric (GC), colon (CC), and rectal (RC) cancers were collected during the same period. Serum ghrelin was tested by ELISA and correlated with clinicopathology of patients with DTMs.

RESULTS

Serum ghrelin was higher in patients (GC, 38 patients; CC, 24; RC, 26) than in 69 healthy individuals and decreased significantly after tumor resection. Nutrition Risk Screening 2002 score and neutrophil:lymphocyte ratio affected perioperative serum ghrelin levels. The epithelial cell marker AE1/AE3 (pan keratin) in patients with GC, tumor location in the colon in patients with CC, and age in patients with RC also affected perioperative serum ghrelin.

CONCLUSIONS

Serum ghrelin might provide early warning of occurrence and guide prognosis of DTMs. Ghrelin can be used when screening for nutritional risk and inflammation. The clinicopathological influence on serum ghrelin in patients with DTMs is related to tumor location in the digestive tract.

GHRELIN LEVEL IN PATIENTS WITH LIVER CIRRHOSIS

BACKGROUND

Ghrelin is a gastro-duodenal hormone which plays a major role in the regulation of food intake, energy balance and gastrokinesis. Ghrelin represents a novel biological marker for assessment of the presence as well as the severity of liver cirrhosis. We aimed to measure the level of plasma ghrelin in patients with liver cirrhosis (compensated and decompensated) and to correlate its level with different studied clinical and laboratory parameters.

SUBJECTS AND METHODS

40 cirrhotic patients were included in a cross-sectional study and divided equally according to the Child-Pugh classification into Group I: patients with compensated liver cirrhosis (Child A), and Group II: patients with decompensated liver cirrhosis (Child B|C). Also, 20 age and sex matched healthy subjects were included as a control group (Group III). All patients were subjected to: full history taking, full clinical examination, routine biochemical studies together with estimation of plasma ghrelin level, assessment of the severity of liver disease according to Child-Pugh classification, also, abdominal ultrasonography was done.

RESULTS

Plasma ghrelin level was low among cirrhotic patients (both compensated and decompensated) in comparison to normal control subjects.

CONCLUSION

Ghrelin can be used as a serum biomarker for detection and assessment of the severity of liver cirrhosis.

Ghrelin gene polymorphism as a genetic biomarker for prediction of therapy induced clearance in Egyptian chronic HCV patients

Ghrelin (GHRL) has important implications for liver disease. It has anti-inflammatory effects, regulates cell proliferation, modulates the fibrogenic response and protects liver tissue. Genetic variations in the GHRL gene may play a crucial role in the development of chronic hepatitis (CH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Therefore, we examined the association of GHRL gene polymorphisms (rs26312 and rs27647), and its serum level to virologic responses to combined sofosbuvir and Simeprevir therapy for a course of 12 successive weeks in Egyptian chronic hepatitis C (CHC) patients.

METHODS

Human genomic and clinical data were collected from 100 Egyptian participants in this study, 90 HCV patients who received sofosbuvir and Simeprevir and 10 non-HCV healthy subjects. Genotyping of GHRL rs26312 and rs27647, were determined with the TaqMan qRT-PCR allele detection assay. The serum GHRL concentrations were determined using enzyme-linked immunosorbent assay (ELISA).

RESULTS

GHRL polymorphisms (rs26312 and rs27647) genotype distributions and allele frequencies did not differ between HCV patients and normal healthy subjects or between patient groups when compared according to the therapeutic response. In addition, we found significant lower serum GHRL levels in CHC patients compared with the healthy controls. However, there was no significant association of the GHRL rs26312 and rs27647 polymorphisms with GHRL levels in CHC patients. We conclude that GHRL SNPs (rs26312 and rs27647) do not affect response to combined sofosbuvir and Simeprevir treatment in chronic Egyptian HCV patients.

Association of Ghrelin Gene Polymorphisms and Serum Ghrelin Levels with the Risk of Hepatitis B Virus-Related Liver Diseases in a Chinese Population

Background

The functions of ghrelin (GHRL) include anti-inflammatory effects, reduction of the fibrogenic response, protection of liver tissue, and regulation of cell proliferation. Genetic variations in the GHRL gene may play an important role in the development of chronic hepatitis B (CHB), liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Therefore, we investigated whether GHRL gene polymorphisms and its serum levels are associated with hepatitis B virus (HBV)-related diseases risk in a Chinese population.

Methods

176 patients with CHB, 106 patients with HBV-related LC, 151 patients with HBV-related HCC, and 167 healthy controls were recruited in the study. Genotyping of GHRL rs26311, rs27647, rs696217, and rs34911341 polymorphisms were determined with the polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and DNA sequencing. The serum GHRL concentrations were determined using enzyme-linked immunosorbent assay (ELISA).

Results

Binary logistic regression analyses adjusting for gender and age revealed that a significant increased risk of LC was found in the GHRL rs26311 GC genotype and combined GC+CC genotypes when compared with the GG genotype (GC vs. GG: OR = 1.671, 95% CI = 1.013–2.757, P = 0.044; GC+CC vs. GG: OR = 1.674, 95% CI = 1.040–2.696, P = 0.034). In subgroup analysis by gender, binary logistic regression analyses adjusting for age showed that the GHRL rs26311 C allele and combined GC+CC genotypes were associated with a significantly increased risk to LC in males (C vs. G OR = 1.416, 95% CI = 1.017–1.972, P = 0.040; GC+CC vs. GG: OR = 1.729, 95% CI = 1.019–2.933, P = 0.042). In addition, we found significant decreased serum GHRL levels in LC patients compared with the healthy controls. However, there was no significant association of the GHRL rs26311 polymorphism with serum GHRL levels in LC patients.

Conclusions

These observations suggest that the GHRL rs26311 polymorphism is associated with an increased risk to HBV-related LC, especially in men. We also found an inverse association of serum GHRL levels with LC.

Ghrelin reduces liver impairment in a model of concanavalin A-induced acute hepatitis in mice

Background and aims

Ghrelin is a 28-amino-acid gut hormone that was first discovered as a potent growth hormone secretagogue. Recently, it has been shown to exert a strong anti-inflammatory effect. The purpose of the study reported here was to explore the effect and mechanism of ghrelin on concanavalin (Con) A-induced acute hepatitis.

Methods

Balb/C mice were divided into four groups: normal control (NC) (mice injected with vehicle [saline]); Con A (25 mg/kg); Con A + 10 μg/kg ghrelin; and Con A + 50 μg/kg ghrelin (1 hour before Con A injection). Pro-inflammatory cytokine levels were detected. Protein levels of phosphoinositide 3-kinase (PI3K); phosphorylated Akt (p-Akt); caspase 3, 8, and 9; and microtubule-associated protein 1 light chain 3 (LC3) were also detected. Perifosine (25 mM) (an Akt inhibitor) was used to investigate whether the protective effect of ghrelin was interrupted by an Akt inhibitor. Protein levels of p-AKT; Bcl-2; Bax; and caspase 3, 8, and 9 were also detected.

Results

Aspartate aminotransferase, alanine aminotransferase, and pathological damage were significantly ameliorated by ghrelin pretreatment in Con A-induced hepatitis. Inflammatory cytokines were significantly reduced by ghrelin pretreatment. Bcl-2; Bax; and caspase 3, 8, and 9 expression were also clearly affected by ghrelin pretreatment, compared with the Con A-treated group. However, the Akt kinase inhibitor reversed the decrease of Bax and caspase 3, 8, 9, and reduced the protein level of p-Akt and Bcl-2. Ghrelin activated the PI3K/Akt/Bcl-2 pathway and inhibited activation of autophagy.

Conclusion

Our results demonstrate that ghrelin attenuates Con A-induced acute immune hepatitis by activating the PI3K/Akt pathway and inhibiting the process of autophagy, which might be related to inhibition of inflammatory cytokine release, and prevention of hepatocyte apoptosis. These effects could be interrupted by an Akt kinase inhibitor.

Perturbation of acyl ghrelin profile after liver transplantation

BACKGROUND

A significant problem to be solved for patients after liver transplantation (LT) is malnutrition with anorexia in the early posttransplant period. We hypothesized that this problem was due to the change in ghrelin metabolism during LT. The aim of this study was to examine the balance of acyl ghrelin (AG) and desacyl ghrelin and the dependence of the regulation mechanism on hepatic-related enzymes in patients during LT.

MATERIALS AND METHODS

AG, desacyl ghrelin, and acyl/total ghrelin (A/T) concentrations in blood samples were measured in 15 patients with liver failure (LF), 15 patients after LT, and 10 controls. The correlations between the participants' ghrelin profiles and hepatic function-related data, including liver enzymes, were evaluated. In vitro assays using synthetic AG for assessment of deacylation activity in serum were performed.

RESULTS

AG and A/T ratio were significantly higher in the LF patients than the patients after LT and controls (AG: 25.9 ± 12.6 versus 16.4 ± 12.6 and 9.8 ± 7.6 fmol/mL, P < 0.05; A/T ratio: 17.4 ± 4.1 versus 12.2 ± 5.5 and 11.8% ± 5.9%, P < 0.05). The serum cholinesterase level was inversely correlated with AG and A/T ratio (P < 0.01). In vitro assays showed that deacylation activity was significantly lower in patients with LF than controls (10.5% versus 42.4%, 90 min; P < 0.01). Degradation of AG was partially suppressed by a cholinesterase inhibitor.

CONCLUSIONS

Deacylation activity was lower in LF patients, which could cause elevation of AG levels. Serum cholinesterase may be responsible for deacylation in humans.

Diagnostic accuracy of acyl-ghrelin and it association with non-alcoholic fatty liver disease in type 2 diabetic patients

Background

Ghrelin is a hormone produced mainly by the cells lining the fundus of the stomach, which is involved in regulation of lipid and glucose metabolism. Two major forms of ghrelin can be found in circulation: an acylated form, and non-acylated form. Serum acyl-ghrelin (AG) concentration is significantly increased in patients with visceral obesity and insulin resistance. This study was conducted to evaluate changes in serum AG levels, its diagnostic accuracy and association with NAFLD in patients with type two diabetes (T2D).

Methods

In this cross-sectional study, 91 T2D patients, age of 40–80 years, were included. All patients were divided into 3 groups. The control group included 28 T2D patients without NAFLD. The main group included 63 T2D patients with NAFLD, which was divided in 2 subgroups depending on transaminase levels: normal (n = 37) and elevated (n = 26) transaminases group. To assess the diagnostic accuracy of AG for NAFLD we used ROC-analysis.

Results

We observed 1.5 (p = 0.016) and 2.5 (p < 0.001) fold increasing of serum AG levels in patients with NAFLD and normal or elevated transaminases compared to control groups. In multivariate logistic regression analysis high AG level was an independent, from transaminases activity, triglycerides (OR 1.791; 95 % CI 1.162–2.759; p = 0.008) and degree of IR (OR 1.599; 95 % CI 1.019–2.508; p = 0.044) predictor that associated with NAFLD. When serum AG used as non-invasive marker for NAFLD detection AUROC was 0.835 (95 % CI 0.752–0.918, p < 0.001). The cut-off value was >0.52 ng/ml, with sensitivity, specificity, PPV and NPV – 60.3 %, 92.8 %, 95.0 %, 50.9 % respectively. For distinguishing patients with NAFLD and elevated transaminases from patients with NAFLD and normal values AG was less effective.

Conclusions

Our study has demonstrated that elevated AG level were associated with NAFLD. Patients with elevated transaminases had significantly higher AG levels. An increase of AG over 0.52 ng/ml can be used as a diagnostic marker for NAFLD detection in patients with T2D.

Assessment of serum acylated ghrelin in children and adolescents with chronic liver diseases: relation to nutritional status

Because ghrelin is one of the key hormones in regulating feeding behavior and caloric status, it was suggested that ghrelin behavior might be closely associated with malnutrition state of patients with chronic liver disease (CLD). Thus, we aimed to assess serum ghrelin levels in children with CLD and its relation to anthropometric parameters and severity of CLD. Forty CLD patients were studied in comparison to 40 controls. All subjects were subjected to history, anthropometric, and laboratory assessment of liver functions and serum acylated ghrelin. Ghrelin was higher in patients than controls being higher with progress of Child's grade and with deterioration of liver functions. Hyperghrelinemia was detected in 62.5% of cases. Ghrelin correlated negatively with body mass index standard deviation score (BMISDS (r = −0.95, P < 0.001)), triceps skin fold thickness (TSFT (r = −0.88, P < 0.001)), and subscapular skin fold thickness (SSFT (r = 0.83, P < 0.001)) percentiles. In conclusion, hyperghrelinemia may represent a compensatory mechanism trying to overcome malnutrition state complicating CLD and can be used as a parameter for early detection and assessment of the severity of malnutrition in children with CLD.

Acylation of ghrelin is increased in heart failure and decreases post heart transplantation

OBJECTIVES

Ghrelin is an anabolic hormone that is elevated in heart failure (HF), with resistance to its anabolic effects. This resolves after heart transplantation (HTx). Ghrelin exists in acylated and des-acyl forms, with the acylated form being primarily responsible for endocrine actions. We tested the hypothesis that ghrelin derangements in HF are due to inadequate acylation and that this resolves post transplantation.

DESIGN

Plasma levels of des-acyl and acylated ghrelin and acylated/total ratios were assessed in HF (n = 20), post-HTx (n = 35), and healthy controls (n = 4), and correlated with each other and with clinical parameters.

RESULTS

Median (interquartile range) of des-acyl ghrelin level, was 167 (121-195) pg/ml in HF versus 149 (130-223) pg/ml in post-HTx, p = NS. Acylated ghrelin level was 76 (51-99) pg/ml versus 13 (0-30) pg/ml, p < 0.001. Acylated/total ratios were 0.33 (0.20-0.47) versus 0.08 (0-0.13), p < 0.001. The correlation between acylated and total ghrelin levels was greater in HF than that in HTx. Acyl ghrelin correlated inversely with body mass index in HF, but not in HTx.

CONCLUSION

Acylated ghrelin and the acylated/total ratio were dramatically higher in HF compared with those in HTx. Acylation rather than secretion of ghrelin is upregulated in HF and the resistance to ghrelin's anabolic and appetite-stimulating effects is not at the level of acylation, but downstream at the ghrelin-receptor level.

Satiety-related hormonal dysregulation in behavioral variant frontotemporal dementia

OBJECTIVE

To investigate whether patients with behavioral variant frontotemporal dementia (bvFTD) have dysregulation in satiety-related hormonal signaling using a laboratory-based case-control study.

METHODS

Fifty-four participants (19 patients with bvFTD, 17 patients with Alzheimer disease dementia, and 18 healthy normal controls [NCs]) were recruited from a tertiary-care dementia clinic. During a standardized breakfast, blood was drawn before, during, and after the breakfast protocol to quantify levels of peripheral satiety-related hormones (ghrelin, cortisol, insulin, leptin, and peptide YY) and glucose. To further explore the role of patients' feeding abnormalities on hormone levels, patients were classified into overeating and nonovereating subgroups based on feeding behavior during separate laboratory-based standardized lunch feeding sessions.

RESULTS

Irrespective of their feeding behavior in the laboratory, patients with bvFTD, but not patients with Alzheimer disease dementia, have significantly lower levels of ghrelin and cortisol and higher levels of insulin compared with NCs. Furthermore, while laboratory feeding behavior did not predict alterations in levels of ghrelin, cortisol, and insulin, only patients with bvFTD who significantly overate in the laboratory demonstrated significantly higher levels of leptin compared with NCs, suggesting that leptin may be sensitive to particularly severe feeding abnormalities in bvFTD.

CONCLUSIONS

Despite a tendency to overeat, patients with bvFTD have a hormonal profile that should decrease food intake. Aberrant hormone levels may represent a compensatory response to the behavioral or neuroanatomical abnormalities of bvFTD.

Independent factors associated with altered plasma active ghrelin levels in HCV-infected patients

BACKGROUND & AIMS

Metabolic disorders are frequently seen in hepatitis C virus (HCV)-infected patients. Ghrelin, a gut hormone, regulates hepatic metabolisms, and must be activated to exert its biological effects. The aims of this study were to investigate changes in plasma active ghrelin levels and identify independent factors associated with plasma active ghrelin levels in HCV-infected patients.

METHODS

We enrolled patients with HCV infection (n = 96), hepatitis B virus (HBV) infection (n = 49), non-alcoholic fatty liver disease (NAFLD; n = 20) and healthy subjects (CON; n = 16). Plasma active ghrelin levels were measured using ELISA. Factors associated with plasma active ghrelin levels were assessed by multivariate and Spearman's correlation analyses.

RESULTS

Plasma active ghrelin levels were significantly lower in relation to the severity of liver disease in both the HBV and HCV groups. Furthermore, HCV infection was identified as an independent factor associated with decreased plasma active ghrelin levels in the multivariate analysis (OR -3.05; 95% CI -0.93 to -19.51; P = 0.0192). Plasma active ghrelin levels were significantly correlated with serum albumin levels in the HCV group (ρ = 0.497, P < 0.0001).

CONCLUSIONS

We demonstrated that liver cirrhosis and HCV infection were independent factors associated plasma active ghrelin levels. Moreover, plasma active ghrelin levels were positively correlated with serum albumin levels among HCV-infected patients. Therefore, active ghrelin levels may be regulated by both progression of liver disease and HCV infection and could be involved in the regulation of serum albumin levels in HCV-infected patients.

Genetic variants associated with the progression of hepatocellular carcinoma in hepatitis C Egyptian patients

BACKGROUND

Hepatocellular carcinoma (HCC) associated to infection with hepatitis C virus (HCV) has become the fastest-rising cause of cancer-related deaths. Genetic variations may play an important role in the development of HCC in HCV patients. Ghrelin exerts anti-inflammatory, antifibrotic and hepatoprotective effects on chronically injured hepatic tissues. Ghrelin gene shows several single nucleotide polymorphisms (SNPs) including -604G/A, Arg51Gln, and Leu72Met. Hemochromatosis gene (HFE) mutations namely C282Y and H63D may cause hepatic iron overload, thus increasing the risk of HCC in HCV patients.

AIM

To investigate the association of progression of HCC with ghrelin and HFE gene polymorphisms in HCV Egyptian patients.

METHODS

Seventy-nine chronic HCV patients (thirty-nine developed HCC and forty did not), and forty healthy control subjects were included in the study. The polymorphisms were evaluated by PCR/RFLP analysis, and related protein levels were measured by either ELISA or colorimetric assays.

RESULTS

The three tested SNPs on ghrelin gene were detected in the studied groups, only one SNP (Arg51Gln) showed significantly higher GA, AA genotypes and A allele frequencies in hepatitis C patients who developed HCC than in hepatitis C patients without HCC and controls. Of the two mutations studied on HFE gene only H63D heterozygous allele was detected, and its frequency did not statistically differ among studied groups.

CONCLUSION

Our results suggest that A allele at position 346 of the ghrelin gene is associated with susceptibility to HCC in hepatitis C patients.

Plasma insulin, leptin, adiponectin, resistin, ghrelin, and melatonin in nonalcoholic steatohepatitis patients treated with melatonin

Insulin resistance, oxidative stress, and an abnormal production of adipokines and cytokines are implicated in the pathogenesis of nonalcoholic steatohepatitis (NASH). Recently, we reported a significant improvement in plasma liver enzymes among patients with NASH treated with melatonin. In this study, we investigated the effect of melatonin, administered at a dose of 10 mg/day for 28 days to 16 patients with histologically proven NASH on insulin resistance (HOMA-IR), on the plasma levels of adiponectin, leptin, ghrelin, and resistin. Additionally, plasma levels of aminotransferases and gamma glutamyltranspeptidase as well as plasma concentrations of melatonin were evaluated. Median baseline values of HOMA-IR, leptin (ng/mL), and resistin (pg/mL) in patients with NASH were significantly higher in comparison with controls: 4.90 versus 1.60, 10.70 versus 4.30, and 152 versus 91, respectively. Median adiponectin level (μg/mL) was decreased in patients compared to controls: 6.40 versus 16.25; no significant difference in ghrelin levels between patients and controls was found. After melatonin treatment, the median value of HOMA-IR was significantly reduced by 60% as compared to baseline values, whereas adiponectin, leptin, and ghrelin plasma levels rose significantly by 119%, 33%, and 20%, respectively; the difference between pre-/posttreatment in plasma resistin levels was not significant. These findings make melatonin a suitable candidate for testing in patients with NASH in the large controlled clinical trials.

Ghrelin, acylated ghrelin, leptin and PYY-3 levels in hyperemesis gravidarum

OBJECTIVE

To assess the serum levels of gut and adipocyte-derived metabolic hormones that control appetite, adipocity, weight gain and energy hemostasis, namely total ghrelin (TG), acylated ghrelin (AG), leptin and PYY-3 in hyperemesis gravidarum (HG).

METHODS

Plasma samples of 86 women in their first trimester pregnancies with HG (n = 30), morning sickness of pregnancy (MSP) (n = 34) and control (n = 22) groups were obtained. Serum levels of TG, AG, leptin and PYY-3 were compared between the groups, and the correlations with severity of symptoms using modified PUQE (Pregnancy Unique Quantification of Emesis) scoring, BMI, E2, hCG and TSH were calculated.

RESULTS

Levels of TG, AG, PYY-3 and the TG/leptin ratio were significantly higher in HG group compared to MSP and the control groups (p ≤ 0.017). AG/TG ratio was significantly lower in the HG group compared to both MSP and control groups (p ≤ 0.017). There were either weak or no significant statistical correlations between the gut and adipose-related hormones and the modified PUQE scores, BMI, E2, hCG and TSH.

CONCLUSION

Gut-derived metabolic hormones ghrelin, AG and PYY-3 may be involved in the HG pathophysiology.

Protective effects of lipocalin-2 (LCN2) in acute liver injury suggest a novel function in liver homeostasis

Lipocalin-2 is expressed under pernicious conditions such as intoxication, infection, inflammation and other forms of cellular stress. Experimental liver injury induces rapid and sustained LCN2 production by injured hepatocytes. However, the precise biological function of LCN2 in liver is still unknown. In this study, LCN2(-/-) mice were exposed to short term application of CCl4, lipopolysaccharide and Concanavalin A, or subjected to bile duct ligation. Subsequent injuries were assessed by liver function analysis, qRT-PCR for chemokine and cytokine expression, liver tissue Western blot, histology and TUNEL assay. Serum LCN2 levels from patients suffering from liver disease were assessed and evaluated. Acute CCl4 intoxication showed increased liver damage in LCN2(-/-) mice indicated by higher levels of aminotransferases, and increased expression of inflammatory cytokines and chemokines such as IL-1β, IL-6, TNF-α and MCP-1/CCL2, resulting in sustained activation of STAT1, STAT3 and JNK pathways. Hepatocytes of LCN2(-/-) mice showed lipid droplet accumulation and increased apoptosis. Hepatocyte apoptosis was confirmed in the Concanavalin A and lipopolysaccharide models. In chronic models (4weeks bile duct ligation or 8weeks CCl4 application), LCN2(-/-) mice showed slightly increased fibrosis compared to controls. Interestingly, serum LCN2 levels in diseased human livers were significantly higher compared to controls, but no differences were observed between cirrhotic and non-cirrhotic patients. Upregulation of LCN2 is a reliable indicator of liver damage and has significant hepato-protective effect in acute liver injury. LCN2 levels provide no correlation to the degree of liver fibrosis but show significant positive correlation to inflammation instead.

Ghrelin, leptin and insulin in cirrhotic children and adolescents: relationship with cirrhosis severity and nutritional status

OBJECTIVE

Ghrelin, leptin, and insulin concentrations are involved in the control of food intake and they seem to be associated with anorexia-cachexia in cirrhotic patients. The present study aimed to investigate the relationship between the nutritional status and fasting ghrelin, leptin and insulin concentrations in pediatric cirrhotic patients.

METHODS

Thirty-nine patients with cirrhosis and 39 healthy controls aged 0-15 years matched by sex and age were enrolled. Severity of liver disease was assessed by Child-Pugh classification, and Pediatric for End Stage Liver Disease (PELD) or Model for End-stage Liver Disease (MELD) scores. Blood samples were collected from patients and controls to assay total ghrelin, acyl ghrelin, leptin and insulin by using a commercial ELISA kit. Anthropometry parameters used were standard deviation score of height-for-age and triceps skinfold thickness-for-age ratio. A multiple linear regression analysis was used to determine the correlation between dependent and independent variables.

RESULTS

Acyl ghrelin was significantly lower in cirrhotic patients than in controls [142 (93-278) pg/mL vs 275 (208-481) pg/mL, P=0.001]. After multiple linear regression analysis, total ghrelin and acyl ghrelin showed an inverse correlation with age; acyl ghrelin was associated with the severity of cirrhosis and des-acyl ghrelin with PELD or MELD scores ≥15. Leptin was positively correlated with gender and anthropometric parameters. Insulin was not associated with any variable.

CONCLUSION

Low acyl ghrelin and high des-acyl ghrelin concentrations were associated with cirrhosis severity, whereas low leptin concentration was associated with undernourishment in children and adolescents with cirrhosis.

Therapeutic potential of ghrelin in restricting-type anorexia nervosa

Anorexia nervosa (AN) is an eating disorder characterized by a decrease in caloric intake and malnutrition. It is associated with a variety of medical morbidities as well as significant mortality. Nutritional support is of paramount importance to prevent impaired quality of life later in life in affected patients. Some patients with restricting-type AN who are fully motivated to gain body weight cannot increase their food intake because of malnutrition-induced gastrointestinal dysfunction. Chronicity of AN prevents participation in social activities and leads to increased medical expenses. Therefore, there is a pressing need for effective appetite-stimulating therapies for patients with AN. Ghrelin is the only orexigenic hormone that can be given intravenously. Intravenous infusion of ghrelin is reported to increase food intake and body weight in healthy subjects as well as in patients with poor nutritional status. Here, we introduce the results of a pilot study that investigated the effects of ghrelin on appetite, energy intake, and nutritional parameters in five patients with restricting-type AN, who are fully motivated to gain body weight but could not increase their food intake because of malnutrition-induced gastrointestinal dysfunction.

Serum leptin and ghrelin in chronic hepatitis C patients with steatosis

AIM: To determine the associations between leptin and ghrelin concentrations and sustained virological response (SVR) in chronic hepatitis C patients with steatosis.

METHODS: We retrospectively assessed 56 patients infected with hepatitis C virus (HCV) genotype-1 and 40 with HCV genotype-3. Patients with decompensated cirrhosis, and those with other causes of chronic liver disease, were excluded. Serum HCV-RNA concentrations were measured before the initiation of treatment; at weeks 12 (for genotype 1 patients), 24 and 48 during treatment; and 24 wk after the end of treatment. Genotype was determined using INNO-LIPA HCV assays, and serum leptin and ghrelin concentrations were measured using enzyme-linked immunosorbent assay. Biopsy specimens were scored according to the Ishak system and steatosis was graded as mild, moderate, or severe, according to the Brunt classification.

RESULTS: Overall, SVR was positively related to the presence of genotype-3, to biopsy-determined lower histological stage of liver disease, and lower grade of steatosis. Patients ≥ 40 years old tended to be less responsive to therapy. In genotype-1 infected patients, SVR was associated with a lower grade of liver steatosis, milder fibrosis, and an absence of insulin resistance. Genotype-1 infected patients who did not achieve SVR had significantly higher leptin concentrations at baseline, with significant increases as the severity of steatosis worsened, whereas those who achieved SVR had higher ghrelin concentrations. In genotype-3 infected patients, SVR was associated only with fibrosis stage and lower homeostasis model assessment insulin resistance at baseline, but not with the degree of steatosis or leptin concentrations. Genotype-3 infected patients who achieved SVR showed significant decreases in ghrelin concentration at end of treatment. Baseline ghrelin concentrations were elevated in responders of both genotypes who had moderate and severe steatosis.

CONCLUSION: Increased serum leptin before treatment may predict non-SVR, especially in HCV genotype-1 infected patients, whereas increased ghrelin may predict SVR in genotype-1.

Study of serum ghrelin changes and its correlation with malnutrition in liver cirrhosis in Egypt

Egypt has the highest prevalence of hepatitis C virus (HCV) all over the world, with an estimated 8-10 million among a population of 68 million having been exposed to the virus and 5-7 million active infections (Frank et al., 2000). It is considered the most common aetiology of chronic liver disease (CLD) in Egypt, where prevalence of antibodies to HCV (anti-HCV) is 10-fold greater than in the United States and Europe (Goldstone et al., 2002; Strickland et al., 2002). We have studied the role of plasma ghrelin, an orexigenic hormone that was found to correlate with malnourishment in CLD depending on Child classification. Sixty patients were divided in three groups according to Child classification and were compared to normal healthy controls (20 subjects). There was a highly significant correlation of plasma ghrelin and body mass index (BMI), mid arm circumference (MAC), waist circumference (WC) and tricuspid skin fold thickness (TSF). Also plasma ghrelin was specific and sensitive by the ROC curve analysis to BMI, which would indicate a new marker for malnourishment and possibility of a novel therapeutic approach.

Ghrelin and reproductive disorders

Ghrelin is an important factor involved in most of the metabolic and hormonal signals which adapt the reproductive functions in conditions of altered energy balance. Moreover, the coordinated role of leptin and ghrelin appears in fact to have a specific role in the regulation of puberty. Systemic action of ghrelin on the reproductive axis involves the control of the hypothalamic-pituitary-gondal axis. In addition, it has been shown that ghrelin may directly act at a gonadal level in both females and males. Available data also demonstrate that sex steroid hormones and gonadotropins may in turn regulate the gonadal effect of ghrelin, as documented by studies performed in females with the polycystic ovary syndrome and in hypogonadal men. Notably, recent studies also confirm a potentially important role for ghrelin in fetal and neonatal energy balance, and specifically in allowing fetal adaptation to an adverse intrauterine environment.

Y-box protein-1/p18 fragment identifies malignancies in patients with chronic liver disease

Background

Immunohistochemical detection of cold shock proteins is predictive for deleterious outcome in various malignant diseases. We recently described active secretion of a family member, denoted Y-box (YB) protein-1. We tested the clinical and diagnostic value of YB-1 protein fragment p18 (YB-1/p18) detection in blood for malignant diseases.

Methods

We used a novel monoclonal anti-YB-1 antibody to detect YB-1/p18 by immunoblotting in plasma samples of healthy volunteers (n = 33), patients with non-cancerous, mostly inflammatory diseases (n = 60), hepatocellular carcinoma (HCC; n = 25) and advanced solid tumors (n = 20). YB-1/p18 was then tested in 111 patients with chronic liver diseases, alongside established tumor markers and various diagnostic measures, during evaluation for potential liver transplantation.

Results

We developed a novel immunoblot to detect the 18 kD fragment of secreted YB-1 in human plasma (YB-1/p18) that contains the cold-shock domains (CSD) 1-3 of the full-length protein. YB-1/p18 was detected in 11/25 HCC and 16/20 advanced carcinomas compared to 0/33 healthy volunteers and 10/60 patients with non-cancerous diseases. In 111 patients with chronic liver disease, YB-1/p18 was detected in 20 samples. Its occurrence was not associated with advanced Child stages of liver cirrhosis or liver function. In this cohort, YB-1/p18 was not a good marker for HCC, but proved most powerful in detecting malignancies other than HCC (60% positive) with a lower rate of false-positive results compared to established tumor markers. Alpha-fetoprotein (AFP) was most sensitive in detecting HCC, but simultaneous assessment of AFP, CA19-9 and YB-1/p18 improved overall identification of HCC patients.

Conclusions

Plasma YB-1/p18 can identify patients with malignancies, independent of acute inflammation, renal impairment or liver dysfunction. The detection of YB-1/p18 in human plasma may have potential as a tumor marker for screening of high-risk populations, e.g. before organ transplantation, and should therefore be evaluated in larger prospective studies.

CXCL5 plasma levels decrease in patients with chronic liver disease

BACKGROUND AND AIMS

CXCL5 (chemokine [C-X-C motif] ligand 5, also known as epithelial neutrophil-activating peptide 78 [ENA78]) belongs to the CXC chemokine family and has been shown to have promitotic effects on hepatocytes. The aim of our study was to assess CXCL5 plasma levels in patients with chronic liver disease.

METHODS

CXCL5 plasma levels were measured in 111 patients with chronic liver disease and 98 healthy controls. The gene expression of CXCL5 and its main receptor, CXC receptor-2, were also determined in liver biopsies from 46 patients.

RESULTS

CXCL5 levels were correlated with clinical presentation, laboratory parameters, and liver histology. Plasma CXCL5 levels in patients with liver cirrhosis were lower than those in healthy controls, and correlated with hepatic biosynthetic capacity, Child-Pugh and model for end-stage liver disease scores. Patients with hepatic necroinflammation and fibrosis on liver histology showed lower plasma CXCL5 levels. In patients with typical clinical complications of cirrhosis, CXCL5 levels were found to be decreased. Intrahepatically, CXCL5 expression was increased in patients with advanced fibrosis and cirrhosis. The isolation of different cellular compartments from mouse livers suggested that hepatic stellate cells and sinusoidal endothelial cells are the main sources of hepatic CXCL5.

CONCLUSIONS

Plasma CXCL5 levels are lower in patients with chronic liver disease, suggesting that CXCL5 might be involved in the pathogenesis of chronic liver disease. CXCL5 could serve as an additional biomarker for hepatic necroinflammation and fibrosis.

Altered fasting and postprandial plasma ghrelin levels in patients with liver failure are normalized after liver transplantation

CONTEXT

Anorexia is a problem of paramount importance in patients with advanced liver failure. Ghrelin has important actions on feeding and weight homeostasis. Experimental data exist, which suggest that ghrelin could protect hepatic tissue. Both fasting and post-oral glucose tolerance test (OGTT) ghrelin concentrations are controversial in liver cirrhosis and are unknown after liver transplantation.

OBJECTIVE

Our aim was to study fasting ghrelin concentrations and their response to an OGTT in liver failure patients before and after liver transplantation.

DESIGN AND METHODS

We included 21 patients with severe liver failure studied before (pretransplantation, PreT) and 6 months after liver transplantation (posttransplantation, PostT), and 10 age- and body mass index-matched healthy or overweight subjects as the control group (Cont). After an overnight fast, 75 g of oral glucose were administered; glucose, insulin, and ghrelin were obtained at baseline and at times 30, 60, 90, and 120 min.

RESULTS

Fasting ghrelin (median and range, pg/ml) levels were lower in PreT: 539 (309-1262) than in Cont: 643 (523-2163), P=0.045. Fasting ghrelin levels increased after liver transplantation, 539 (309-1262) vs 910 (426-3305), for PreT and PostT respectively, P=0.001. The area under the curve (AUC) of ghrelin (pg/ml min) was lower in PreT: 63,900 (37,260-148,410) than in Cont: 76,560 (56,160-206,385), P=0.027. The AUC of ghrelin increased in PostT, 63,900 (37,260-148,410) vs 107,595 (59,535-357,465), for PreT and PostT respectively, P=0.001. Fasting levels and the AUC of ghrelin were similar in PosT and Cont.

CONCLUSIONS

Decreased fasting and post-OGTT ghrelin levels in liver failure patients were normalized after liver transplantation.

Dysregulation of plasma ghrelin in alcoholic cirrhosis

OBJECTIVE

Abnormalities in circulating ghrelin have been reported in chronic liver disease. This study assessed the response of anabolic peptides ghrelin, growth hormone (GH) and insulin-like growth factor 1 (IGF-1) in patients with alcoholic cirrhosis and healthy subjects to oral glucose. In a previous study, using oral glucose we identified loss of ghrelin regulation in nonalcoholic steato-hepatitis. PATIENTS/DESIGN/MEASUREMENTS: Fourteen patients with alcoholic cirrhosis were compared with 11 healthy subjects. Patients with cirrhosis were studied when adjudged clinically stable in hospital. After an overnight fast, they ingested 100-g glucose dissolved in 250 ml of water. Blood was sampled before and every 20 minutes after ingestion for 120 minutes. Plasma acylated and des-acyl ghrelin, GH, IGF-1 and insulin were assayed by ELISA.

RESULTS

Expressed as median (95% CI): 120-minutes integrated acylated ghrelin was 26 (19-66) in controls compared to 170 (129-252) pg/ml per hour in patients with cirrhosis; P < 0.001. Both groups exhibited a normal postglucose plasma total ghrelin profile. Among patients with cirrhosis (compared to controls), growth hormone was increased 15-fold and IGF-1 decreased 4-fold. Acylated ghrelin correlated with GH (Spearman r = 0.69, P = 0.0015) in control subjects but not in patients with cirrhosis.

CONCLUSIONS

Acylated ghrelin is markedly increased in alcoholic cirrhosis, with apparent preservation of normal postprandial mechanisms of gastric ghrelin secretion. GH is also increased; however, its correlation with acylated ghrelin (confirmed in healthy subjects) is absent in patients with cirrhosis. Despite increased ghrelin and GH, patients with alcoholic cirrhosis remain anorexic and catabolic suggesting potential tissue resistance to the actions of these anabolic peptides.

Total and acylated ghrelin in liver cirrhosis: correlation with clinical and nutritional status

OBJECTIVES

The pathogenesis of anorexia in cirrhotic patients is complex and the appetite-modulating hormone ghrelin could be involved. Acylated ghrelin is the biologically active form that modifies insulin sensitivity and body composition. The aim of the present study was to compare acylated and total ghrelin concentration in patients with liver cirrhosis and to investigate the possible relationship between ghrelin and clinical and nutritional parameters.

DESIGN AND METHODS

Sixty patients with viral liver cirrhosis who did not have hepatocellular carcinoma or acute infections were studied. Twenty healthy volunteers were recruited after matching for age, gender, and body mass index with the patients and served as controls. Fasting levels of total, acylated ghrelin, leptin, TNF-alpha and insulin were measured in all subjects, in addition, clinical and nutrition parameters were assessed.

RESULTS

In cirrhotic patients, plasma levels of both acylated and total ghrelin were significantly higher than those in the controls. The mean plasma acylated ghrelin levels were significantly higher in Child C cirrhosis compared to Child A and B. Ghrelin (total and acylated) were negatively correlated with leptin in cirrhotic patients confirming the fact that leptin acts as a physiological counterpart of ghrelin.

CONCLUSIONS

Nutritional and metabolic abnormalities in cirrhotic patients may be dependent on the changes in the ghrelin/leptin systems, mainly the acylated form of ghrelin.

Functional contribution of elevated circulating and hepatic non-classical CD14CD16 monocytes to inflammation and human liver fibrosis

Background

Monocyte-derived macrophages critically perpetuate inflammatory responses after liver injury as a prerequisite for organ fibrosis. Experimental murine models identified an essential role for the CCR2-dependent infiltration of classical Gr1/Ly6C⁺ monocytes in hepatic fibrosis. Moreover, the monocyte-related chemokine receptors CCR1 and CCR5 were recently recognized as important fibrosis modulators in mice. In humans, monocytes consist of classical CD14⁺CD16⁻ and non-classical CD14⁺CD16⁺ cells. We aimed at investigating the relevance of monocyte subpopulations for human liver fibrosis, and hypothesized that ‘non-classical’ monocytes critically exert inflammatory as well as profibrogenic functions in patients during liver disease progression.

Methodology/Principal Findings

We analyzed circulating monocyte subsets from freshly drawn blood samples of 226 patients with chronic liver disease (CLD) and 184 healthy controls by FACS analysis. Circulating monocytes were significantly expanded in CLD-patients compared to controls with a marked increase of the non-classical CD14⁺CD16⁺ subset that showed an activated phenotype in patients and correlated with proinflammatory cytokines and clinical progression. Correspondingly, CD14⁺CD16⁺ macrophages massively accumulated in fibrotic/cirrhotic livers, as evidenced by immunofluorescence and FACS. Ligands of monocyte-related chemokine receptors CCR2, CCR1 and CCR5 were expressed at higher levels in fibrotic and cirrhotic livers, while CCL3 and CCL4 were also systemically elevated in CLD-patients. Isolated monocyte/macrophage subpopulations were functionally characterized regarding cytokine/chemokine expression and interactions with primary human hepatic stellate cells (HSC) in vitro. CD14⁺CD16⁺ monocytes released abundant proinflammatory cytokines. Furthermore, CD14⁺CD16⁺, but not CD14⁺CD16⁻ monocytes could directly activate collagen-producing HSC.

Conclusions/Significance

Our data demonstrate the expansion of CD14⁺CD16⁺ monocytes in the circulation and liver of CLD-patients upon disease progression and suggest their functional contribution to the perpetuation of intrahepatic inflammation and profibrogenic HSC activation in liver cirrhosis. The modulation of monocyte-subset recruitment into the liver via chemokines/chemokine receptors and their subsequent differentiation may represent promising approaches for therapeutic interventions in human liver fibrosis.

Regulation and prognostic relevance of serum ghrelin concentrations in critical illness and sepsis

Introduction

Ghrelin has been recently identified as a mediator of various beneficial effects in animal models of sepsis. At present, no data are available concerning specific properties of ghrelin in critically ill patients from large cohorts. In order to identify possible pathogenic functions of ghrelin in critically ill patients and human sepsis from a clinical point of view, we aimed at analyzing ghrelin serum concentrations in a large cohort of well characterized patients with critical illness.

Methods

A total of 170 critically ill patients (122 with sepsis, 48 without sepsis) were studied prospectively on admission to the Medical intensive care unit (ICU) and compared to 60 healthy controls. Careful assessment of clinical data, various laboratory parameters, metabolic and endocrine functions as well as investigational inflammatory cytokine profiles have been performed, and patients were followed for approximately three years.

Results

Ghrelin serum concentrations are elevated in critically ill patients as compared to healthy controls, but do not differ between sepsis and non-sepsis patients. The underlying etiologies of critical diseases are not associated with ghrelin serum levels. Neither pre-existing diabetes mellitus nor body mass index is correlated to serum ghrelin concentrations. Ghrelin is not correlated to markers of inflammation or hepatic function in critically ill patients. In the subgroup of non-sepsis patients, ghrelin correlates inversely with renal function and markers of carbohydrate metabolism. High ghrelin levels are an indicator for a favourable prognosis concerning mortality at the ICU in sepsis patients. Furthermore, ghrelin is significantly associated with the necessity of ventilation in critically ill patients.

Conclusions

Ghrelin serum concentrations are elevated in all circumstances of critical disease, including sepsis and non-sepsis patients. High ghrelin levels are a positive predictor of ICU-survival in sepsis patients, matching previous results from animal models. Future experimental and clinical studies are needed to evaluate ghrelin as a novel prognostic tool in ICU patients and its potential therapeutic use in sepsis.

Ghrelin gene products and the regulation of food intake and gut motility

A breakthrough using "reverse pharmacology" identified and characterized acyl ghrelin from the stomach as the endogenous cognate ligand for the growth hormone (GH) secretagogue receptor (GHS-R) 1a. The unique post-translational modification of O-n-octanoylation at serine 3 is the first in peptide discovery history and is essential for GH-releasing ability. Des-acyl ghrelin, lacking O-n-octanoylation at serine 3, is also produced in the stomach and remains the major molecular form secreted into the circulation. The third ghrelin gene product, obestatin, a novel 23-amino acid peptide identified from rat stomach, was found by comparative genomic analysis. Three ghrelin gene products actively participate in modulating appetite, adipogenesis, gut motility, glucose metabolism, cell proliferation, immune, sleep, memory, anxiety, cognition, and stress. Knockdown or knockout of acyl ghrelin and/or GHS-R1a, and overexpression of des-acyl ghrelin show benefits in the therapy of obesity and metabolic syndrome. By contrast, agonism of acyl ghrelin and/or GHS-R1a could combat human anorexia-cachexia, including anorexia nervosa, chronic heart failure, chronic obstructive pulmonary disease, liver cirrhosis, chronic kidney disease, burn, and postsurgery recovery, as well as restore gut dysmotility, such as diabetic or neurogenic gastroparesis, and postoperative ileus. The ghrelin acyl-modifying enzyme, ghrelin O-Acyltransferase (GOAT), which attaches octanoate to serine-3 of ghrelin, has been identified and characterized also from the stomach. To date, ghrelin is the only protein to be octanylated, and inhibition of GOAT may have effects only on the stomach and is unlikely to affect the synthesis of other proteins. GOAT may provide a critical molecular target in developing novel therapeutics for obesity and type 2 diabetes.

Ghrelin attenuates hepatocellular injury and liver fibrogenesis in rodents and influences fibrosis progression in humans

There are no effective antifibrotic therapies for patients with liver diseases. We performed an experimental and translational study to investigate whether ghrelin, an orexigenic hormone with pleiotropic properties, modulates liver fibrogenesis. Recombinant ghrelin was administered to rats with chronic (bile duct ligation) and acute (carbon tetrachloride) liver injury. Hepatic gene expression was analyzed by way of microarray analysis and quantitative polymerase chain reaction. The hepatic response to chronic injury was also evaluated in wild-type and ghrelin-deficient mice. Primary human hepatic stellate cells were used to study the effects of ghrelin in vitro. Ghrelin hepatic gene expression and serum levels were assessed in patients with chronic liver diseases. Ghrelin gene polymorphisms were analyzed in patients with chronic hepatitis C. Recombinant ghrelin treatment reduced the fibrogenic response, decreased liver injury and myofibroblast accumulation, and attenuated the altered gene expression profile in bile duct-ligated rats. Moreover, ghrelin reduced the fibrogenic properties of hepatic stellate cells. Ghrelin also protected rats from acute liver injury and reduced the extent of oxidative stress and inflammation. Ghrelin-deficient mice developed exacerbated hepatic fibrosis and liver damage after chronic injury. In patients with chronic liver diseases, ghrelin serum levels decreased in those with advanced fibrosis, and ghrelin gene hepatic expression correlated with expression of fibrogenic genes. In patients with chronic hepatitis C, polymorphisms of the ghrelin gene (-994CT and -604GA) influenced the progression of liver fibrosis.

CONCLUSION

Ghrelin exerts antifibrotic effects in the liver and may represent a novel antifibrotic therapy.

Ghrelin in the regulation of body weight and metabolism

Ghrelin, a peptide hormone predominantly produced by the stomach, was isolated as the endogenous ligand for the growth hormone secretagogue receptor. Ghrelin is a potent stimulator of growth hormone (GH) secretion and is the only circulatory hormone known to potently enhance feeding and weight gain and to regulate energy homeostasis following central and systemic administration. Therapeutic intervention with ghrelin in catabolic situations may induce a combination of enhanced food intake, increased gastric emptying and nutrient storage, coupled with an increase in GH thereby linking nutrient partitioning with growth and repair processes. These qualities have fostered the idea that ghrelin-based compounds may have therapeutic utility in treating malnutrition and wasting induced by various sub-acute and chronic disorders. Conversely, compounds that inhibit ghrelin action may be useful for the prevention or treatment of metabolic syndrome components such as obesity, impaired lipid metabolism or insulin resistance. In recent years, the effects of ghrelin on glucose homeostasis, memory function and gastrointestinal motility have attracted considerable amount of attention and revealed novel therapeutic targets in treating a wide range of pathologic conditions. Furthermore, discovery of ghrelin O-acyltransferase has also opened new research opportunities that could lead to major understanding of ghrelin physiology. This review summarizes the current knowledge on ghrelin synthesis, secretion, mechanism of action and biological functions with an additional focus on potential for ghrelin-based pharmacotherapies.

Serum ghrelin, adipokine and insulin levels in children with acute hepatitis

OBJECTIVES

Recent reports suggest that adipokines are potent modulators of inflammation. We tested the hypothesis that the decreased food intake and the acute liver disease might be associated with changes of serum ghrelin, adipokines and insulin levels.

METHODS

Fasting ghrelin, adiponectin, leptin, resistin and insulin were measured in 25 children suffering from acute viral hepatitis, caused by either hepatitis A or Epstein-Barr viruses. The age of the patients ranged from 2.2 to 17.2 years (mean: 10.4 years); 10 male and 15 female. Samples for hormones and liver function tests were drawn at 08 : 00 to 09 : 00 h after an overnight fast. The first samples were collected in the morning after the day of admission, the second samples after 2 months of recovery.

RESULTS

Ghrelin and adiponectin levels were significantly higher during hepatitis than after recovery (831.4+/-276.44 vs. 736.21+/-274.91 pg/ml, P<0.0001; and 22.91+/-12.93 vs. 15.16+/-8.81 microg/ml, P<0.001, respectively). Adiponectin levels correlated significantly with age-specific and sex-specific body mass index-matched percentile values as well (P=0.0062). Linear regression analysis confirmed that there was a significant association of changes in serum ghrelin and resistin levels and the severity of hepatitis (P=0.005; P<0.05). We could verify a marginal relationship of the changes of serum leptin and the severity of the disease (P=0.0646).

CONCLUSION

This study confirms that there are significant changes in serum levels of ghrelin, and adipokines in disease-associated malnutrition and acute hepatitis.

Fasting and postprandial plasma ghrelin levels are decreased in patients with liver failure previous to liver transplantation

Anorexia is a problem of paramount importance in patients with advanced liver failure. Ghrelin has important actions on feeding and weight homeostasis. Concentrations of ghrelin are controversial in liver cirrhosis. Our aim was to study fasting ghrelin and their response to an oral glucose tolerance test (OGTT) in liver failure patients and normal subjects.

METHODS

We included 16 patients with severe liver failure prior to liver transplantation. As a control group we included 10 age- and BMI-matched healthy subjects. After an overnight fast, 75 g of oral glucose were administered; glucose, insulin, and ghrelin were obtained at baseline and at times 30, 60, 90, and 120 min, respectively.

RESULTS

Fasting ghrelin (median and range) were statistically significantly lower for patients compared to the controls, 527 (377-971) pg/ml vs. 643 (523-2163) pg/ml, P = 0.045, for patients and controls, respectively. The area under the curve for total ghrelin post-OGTT were lower in end-stage liver failure patients than in the control group, 58815 (44730-87420) pg/ml min vs. 76560 (56160-206385) pg/ml min, for patients and controls, respectively, P = 0.027.

CONCLUSIONS

Ghrelin levels are significantly decreased both fasting and post-OGTT in patients with liver failure candidates for transplantation. Decreased ghrelin levels could contribute to anorexia in patients with cirrhosis.

Altered basal and postprandial plasma melatonin, gastrin, ghrelin, leptin and insulin in patients with liver cirrhosis and portal hypertension without and with oral administration of melatonin or tryptophan

This investigation was designed to assess the effects of oral administration of melatonin (10 mg) and tryptophan (Trp) (500 mg) on fasting and postprandial plasma levels of melatonin, gastrin, ghrelin, leptin and insulin in 10 healthy controls and in age-matched patients with liver cirrhosis (LC) and portal hypertension. Fasting plasma melatonin levels in LC patients were about five times higher (102 +/- 15 pg/mL) than in healthy controls (22 +/- 3 pg/mL). These levels significantly increased postprandially in LC patients, but significantly less so in controls. Treatment with melatonin or L-Trp resulted in a further significant rise in plasma melatonin, both under fasting and postprandial conditions, particularly in LC patients. Moreover, plasma gastrin, ghrelin, leptin and insulin levels under fasting and postprandial conditions were significantly higher in LC subjects than in healthy controls and they further rose significantly after oral application of melatonin or Trp. This study shows that: (a) patients with LC and portal hypertension exhibit significantly higher fasting and postprandial plasma melatonin levels than healthy subjects; (b) plasma ghrelin, both in LC and healthy controls reach the highest values under fasting conditions, but decline postprandially, especially after oral application of melatonin or Trp; and (c) plasma melatonin, gastrin, ghrelin and insulin levels are altered significantly in LC patients with portal hypertension compared with that in healthy controls possibly due to their portal systemic shunting and decreased liver degradation.

Levels of ghrelin, GH, GRH and their clinical significances in patients with hepatitis B related liver cirrhosis

AIM: To investigate the relationship between serum growth hormone (GH) and ghrelin, growth releasing hormone (GRH) and its clinical significance, and to study the expression of gastric ghrelin in patients with hepatitis B-related liver cirrhosis.

METHODS: Fifty-two patients with hepatitis B-related liver cirrhosis (LC) and 17 chronic HBV-infected patients as controls were enrolled in this study. The gender and average age were comparable between LC and control patients. Fasting plasma ghrelin levels, GRH and GH were measured using ELISA. The gastric expression of ghrelin was determined using immunohistochemistry staining.

RESULTS: Plasma ghrelin levels were slightly but not significantly decreased in hepatitis B related LC patients when compared with controls. The Plasma ghrelin levels in Child C patients were significantly decreased compared with Child A patients(0.75 ± 0.479 ng/L vs 1.38 ± 1.064 ng/L, P < 0.05). The Plasma ghrelin levels showed negative but not significant correlation to plasma GH levels, and positive correlations to serum GRH (r = 0.868, P < 0.001), blood urea nitrogen, albumin and hemoglobin (r = 0.357, 0.377, 0.367, all P < 0.05) in hepatitis B related LC patients.

CONCLUSION: The increased serum growth hormone levels in hepatitis B-related liver cirrhosis patients may be related to the increased GRH. These data suggest that fasting plasma ghrelin levels may be a useful indicator reflecting malnutrition in liver cirrhosis patients.

Long-term effects of ghrelin and ghrelin receptor agonists on energy balance in rats

Ghrelin, an endogenous ligand of the growth hormone secretagogue receptor (GHS-R), is the only circulating agent to powerfully promote a positive energy balance. Such action is mediated predominantly by central nervous system pathways controlling food intake, energy expenditure, and nutrient partitioning. The ghrelin pathway may therefore offer therapeutic potential for the treatment of catabolic states. However, the potency of the endogenous hormone ghrelin is limited due to a short half-life and the fragility of its bioactivity ensuring acylation at serine 3. Therefore, we tested the metabolic effects of two recently generated GHS-R agonists, BIM-28125 and BIM-28131, compared with ghrelin. All agents were administered continuously for 1 mo in doses of 50 and 500 nmol x kg(-1) x day(-1) using implanted subcutaneous minipumps in rats. High-dose treatment with single agonists or ghrelin increased body weight gain by promoting fat mass, whereas BIM-28131 was the only one also increasing lean mass significantly. Food intake increased during treatment with BIM-28131 or ghrelin, whereas no effects on energy expenditure were detected. With the lower dose, only BIM-28131 had a significant effect on body weight. This also held true when the compound was administered by subcutaneous injection three times/day. No symptoms or signs of undesired effects were observed in any of the studies or treated groups. These results characterize BIM-28131 as a promising GHS-R agonist with an attractive action profile for the treatment of catabolic disease states such as cachexia.

The role of ghrelin and ghrelin analogues in wasting disease

PURPOSE OF REVIEW

The purpose of this review is to summarize recent studies that investigated the role of ghrelin and ghrelin analogs in wasting conditions.

RECENT FINDINGS

Numerous studies have demonstrated potential beneficial effects exerted by ghrelin in a number of diseases associated with wasting. Besides ghrelin's orexigenic effect, anabolic as well as anti-inflammatory activity mediated by ghrelin have been investigated in wasting conditions such as cancer, diabetes mellitus, malabsorptive diseases, chronic obstructive pulmonary disease, anorexia nervosa, renal failure, liver failure, and chronic heart failure. Encouraging results have been obtained from experimental studies and a few clinical trials using subcutaneous administration of ghrelin and ghrelin agonists in cachexia. In-vitro studies have shown ghrelin and des-acyl ghrelin biological activities on proliferation of tumor cells and abnormal tissues.

SUMMARY

The recent studies support the possible positive effects of ghrelin in therapeutic approaches and adjunct treatment of a number of diseases associated with wasting. Utilization of agonists of the ghrelin receptor growth hormone secretagogue-1a is a promising approach for clinical use. Randomized and placebo-controlled studies, including large number of patients are further required.

Ghrelin in pathological conditions

The recently identified gastric hormone ghrelin was initially described as a natural Growth Hormone Secretagogue Receptor ligand. Apart from ghrelin's first discovered action, which was the stimulation of Growth Hormone release, implications for many other functions have been reported. It seems that ghrelin exhibits an important role in conditions related to processes regulating nutrition, body composition and growth, as well as heart, liver, thyroid or kidney dysfunction. In this review, current available knowledge about ghrelin's role in various pathological conditions is presented.

Serum levels of ghrelin, leptin, IGF-I, IGFBP-3, insulin, thyroid hormones and cortisol in prepubertal children with iron deficiency

The aim of the present study is to investigate possible alterations in ghrelin and other hormone levels related to appetite and somatic growth in children with iron deficiency anemia. Twenty-five patients and 25 healthy controls that were prepubertal and within normal limits regarding height and BMI standard deviation scores were recruited. Ghrelin, leptin, IGF-I, IGFBP-3, insulin, thyroid hormones and cortisol levels were studied. Ghrelin, insulin and IGF-I levels were significantly low in the study group (ghrelin 13.58 +/- 16.32 vs. 35.39 +/- 23.69 ng/ml, p<.001; insulin 3.41 +/- 2.42 vs. 5.67 +/- 1.09 mU/ml, p = .008 and IGF-I 126.94 +/- 92.82 vs. 203 +/- 105.1 ng/ml, p = .015). We concluded that low ghrelin and insulin levels might be causes of the appetite loss in iron deficiency and as a result of appetite loss and undernutrition as well as by direct effects they might be related with growth retardation, which could be also influenced by low IGF-I levels.

Bone morphogenetic protein 7 is elevated in patients with chronic liver disease and exerts fibrogenic effects on human hepatic stellate cells

Hepatic stellate cells (HSCs) are the main extracellular matrix (ECM)-producing cells in liver fibrogenesis. The excessive synthesis of ECM proteins deteriorates hepatic architecture and results in liver fibrosis and cirrhosis. This study investigated the role of bone morphogenetic protein 7 (BMP7) as a member of the transforming growth factor (TGF)-beta superfamily in chronic liver disease. Plasma levels of BMP7 were significantly elevated in patients with chronic liver disease compared with healthy controls. Immunohistochemistry of cirrhotic human liver demonstrated upregulated BMP7 protein expression in hepatocytes as compared with normal human liver. Because gene expression for all putative BMP7 receptors was induced during the culture activation process of primary human HSCs, we studied the effects of BMP7 on hTERT immortalized human HSCs in vitro. BMP7, as expressed and secreted after infection with adenoviruses encoding BMP7 (AdBMP7), increased proliferation of HSCs. The mRNA and protein expression of type I collagen and fibronectin was increased in BMP7-stimulated HSCs. Elevated systemic and hepatic levels of BMP7 in patients with chronic liver disease may contribute to progression of liver fibrogenesis in vivo.