GH/IGF system, cirrhosis and liver transplantation

Probiotic supplementation affects IGF-1 and leptin levels in Nile tilapia hepatopancreatic tissue

ABSTRACT This work aimed to assess the effect of the probiotic strain, Lactobacillus plantarum, on the levels of leptin, IGF-1 and their receptors on the hepatopancreatic tissues of Nile tilapia (Oreochromis niloticus) and then correlate fish growth performance and gut microbiological parameters. Fish juveniles (±23g) were reared in a recirculation system with constant aeration and temperature (25°C). They were distributed into six polyethylene tanks (45L) and fed twice a day at 5% of the tank biomass with the respective diets: control (commercial diet without probiotic) and supplemented with L. plantarum inoculum (1 x 108 CFU mL-1), both in triplicate. After 30 days of feeding, L. plantarum-fed fishes showed greater weekly growth rate, final weight, and feed conversion rate, in addition to higher count of lactic-acid bacteria and lower count of pathogenic bacteria in the intestinal tract, when compared to the control group. The immunostaining intensity for IGF-1 and leptin hormones was lower after L. plantarum supplementation than in the control group, with no change in the level for receptors. This reduction could implicate important changes in fish metabolism and homeostasis.

Serum minerals (Ca, P, Co, Mn, Ni, Cd) and growth hormone (IGF-1 and IGF-2) levels in postmenopausal Saudi women with osteoporosis

Osteoporosis is reported to be common among Saudi women. Several minerals appear to be important determinants of insulin-like growth factor (IGF), the bioactivity of which regulates bone and mineral metabolism. Here we proposed that mineral status may alter the IGF system among individuals with osteoporosis. This study aims to evaluate the relationships between essential elements and IGF levels among postmenopausal Saudi women with osteoporosis. A total of 128 postmenopausal Saudi women aged ≥50 years old were recruited in this study. Diagnosis of osteoporosis was done by using dual-energy x-ray absorptiometry to determine the bone minerals density (BMD). Serum calcium and phosphate were determined using routine chemical analyzer. Serum Co, Mn, Ni, Cd were measured using inductively coupled plasma mass spectrometry. Serum IGF-1 and IGF-2 were determined using Luminex xMAP. Using stepwise linear regression analysis, only Cd was identified to be significantly associated with IGF1 in osteoporosis, explaining 3% (confidence interval 0.01-0.05; P = 0001) of the variance perceived. Our results suggest that Cd exposure indirectly affects BMD which may increase the risk of osteoporosis in postmenopausal women. Further longitudinal study using a larger sample size is recommended to determine causality of Cd levels and IGF-1.

Postoperative Insulin-Like Growth Factor 1 Levels Reflect the Graft's Function and Predict Survival after Liver Transplantation

Background

The reduction of insulin-like growth factor 1 (IGF-1) plasma levels is associated with the degree of liver dysfunction and mortality in cirrhotic patients. However, little research is available on the recovery of the IGF-1 level and its prognostic role after liver transplantation (LT).

Methods

From April 2010 to May 2011, 31 patients were prospectively enrolled (25/6 M/F; mean age±SEM: 55.2±1.4 years), and IGF-1 serum levels were assessed preoperatively and at 15, 30, 90, 180 and 365 days after transplantation. The influence of the donor and recipient characteristics (age, use of extended criteria donor grafts, D-MELD and incidence of early allograft dysfunction) on hormonal concentration was analyzed. The prognostic role of IGF-1 level on patient survival and its correlation with routine liver function tests were also investigated.

Results

All patients showed low preoperative IGF-1 levels (mean±SEM: 29.5±2.1), and on postoperative day 15, a significant increase in the IGF-1 plasma level was observed (102.7±11.7 ng/ml; p<0.0001). During the first year after LT, the IGF-1 concentration remained significantly lower in recipients transplanted with older donors (>65 years) or extended criteria donor grafts. An inverse correlation between IGF-1 and bilirubin serum levels at day 15 (r = -0.3924, p = 0.0320) and 30 (r = -0.3894, p = 0.0368) was found. After multivariate analysis, early (within 15 days) IGF-1 normalization [Exp(b) = 3.913; p = 0.0484] was the only prognostic factor associated with an increased 3-year survival rate.

Conclusion

IGF-1 postoperative levels are correlated with the graft’s quality and reflect liver function. Early IGF-1 recovery is associated with a higher 3-year survival rate after LT.

Relationship between GH/IGF-1 axis, graft recovery, and early survival in patients undergoing liver transplantation

Background. High levels of IGF-1 have been reported in patients with initial poor function of the graft after liver transplantation (LT). Correlation with other clinical variables or early survival has not been extensively investigated. Aim. To evaluate the GH/IGF-1 profile as a function of liver recovery and patients' early survival after LT. Methods. 30 transplanted patients (23 survivors and 7 nonsurvivors), were retrospectively enrolled in the study. GH and IGF-1 serum levels were assessed at baseline, graft reperfusion, and 1, 7, 15, 30 , 90, and 360 days after LT. Individual biochemical variables were also recorded. Results. After grafting, IGF-1 in blood linearly correlated with cholesterol (r = 0.6, P = 0.001). IGF-1 levels from day 15 after surgery were statistically higher in survivors as compared to nonsurvivors. ROC curves analysis identified an IGF-1 cut-off >90 μg/L, from day 15 after surgery, as a good predictor of survival (sensitivity 86%, specificity 95%, and P < 0.001). Conclusions. After LT, GH levels correlate with the extent of cytolysis, while IGF-1 is an indicator of liver synthetic function recovery. IGF-1 levels >90 μg/L (day 15–30) seem to be an indicator of short-term survival.

Effects of administration of subtoxic doses of acetaminophen on liver and blood levels of insulin-like growth factor-1 in rats

Acetaminophen (APAP) is widely used in the treatment of pain. Toxic doses of APAP cause acute liver failure, but therapeutic doses are believed to be safe. The purpose of this study is to investigate the effects of administration of subtoxic doses of APAP on liver and blood levels of insulin-like growth factor-1 (IGF-1) in rats. Low dose (100 mg/kg) and high dose (250 mg/kg) of APAP were intraperitoneally injected into Wistar albino rats. Following administration of therapeutic doses of APAP, there were no significant changes in serum transaminases and liver glutathione levels. Both doses of APAP induced a decrease in liver and blood levels of IGF-1 when compared with the controls. There was no significant difference in liver IGF-1 levels between the high-dose and low-dose APAP groups; however, there was a significant difference in blood IGF-1 levels between both the groups. The histological examination showed that low dose of APAP induced mild degree of structural change, while high dose of APAP induced severe structural damage. In conclusion, these results suggest that blood IGF-1 levels may have a value in predicting hepatic damage resulting from therapeutic doses of APAP.

Serum IGF-1 levels correlate negatively to liver damage in diabetic rats

Diabetes and insulin resistance frequently cause liver damage. Diabetes also causes reduction in liver and blood IGF-1 levels. We investigated the relation between liver damage and IGF-1 levels in diabetic rats. Fourteen Wistar albino rats were divided into control and diabetic groups. Diabetes was induced by streptozotocin. Rats were sacrificed for biochemical and histologic examinations 2 weeks after streptozotocin injection. Serum and liver IGF-1 levels were decreased, liver malondialdehyde (MDA) levels were increased, glutathione peroxidase (GPx) enzymes activities were decreased and serum alanine aminotransferase (ALT) levels were increased in diabetic group. Microscopic examination of liver revealed that normal tissue organization was disrupted in streptozotocin-induced diabetic rats. There was a strongly positive correlation between blood glucose levels and liver injury, and blood and liver IGF-1 levels. There was a strongly negative correlation between blood IGF-1 levels and hepatic injury. Our results suggest that reduction of blood IGF-1 levels correlates with hepatic injury and circulating IGF-1 levels may have predictive value for determining hepatic damage that results from diabetes. In addition, circulating IGF-1 levels are correlated with glutathione levels and the oxidative stress status of diabetic rat liver.

Evaluation of growth after liver transplantation in Turkish children

AIMS

Currently, the main interest in childhood liver transplantation (LT) is to prevent long-term complications and optimize growth. The aim of this study is to analyze (1) nutritional status in the pretransplantation period, and (2) posttransplantation growth and associated factors in children.

PATIENTS AND METHODS

Eighty children were included in the study. Height (Z (H)) and weight (Z (W)) Z scores were calculated before transplantation and postoperatively at the 6th month and 1st, 2nd, 3rd, 4th, and 5th year.

RESULTS

Patients' Z (H) and Z (W) scores at LT were -1.6 ± 1.3 and -1.5 ± 1.4, respectively. Both Z (H) and Z (W) scores increased after LT, especially in the first 6 months, and then continued to rise gradually. Both reached beyond -1 Z score at 2nd year and -0.5 at 4th year. Age, primary diagnosis, total steroid dose (<1,000 mg), and absence of rejection episodes had positive impact on posttransplantation growth, whereas gender, immunosuppression type, surgical complications, and presence of tumor had no impact on posttransplantation growth. Age at time of LT was negatively correlated with Z (W) score at 5th year (P = 0.02, r = -0.43). Both Z (W) and Z (H) scores at time of LT were positively correlated with Z (W) and Z (H) scores and negatively correlated with ∆Z (W) and ∆Z (H) scores at 5th year.

CONCLUSIONS

LT is not only a modern, life-saving treatment technique but also an efficient method of facilitating growth, an indispensable component of childhood and the best indicator of health.

Insulin-like growth factor-I and the liver

Insulin-like growth factors (IGFs) play an essential role in growth and development, as well as in the overall cellular regulation and metabolism in the human body. In chronic liver disease, IGF levels are decreased, and the circulating levels correlate to the extent of hepatocellular dysfunction. Patients with cirrhosis are characterised by a variety of metabolic disturbances, including nutritional and metabolic complications such as insulin resistance, malnutrition, osteopenia and hypogonadism, all related to IGF-I deficiency. The complex process of hepatic fibrogenesis and the systemic consequences in cirrhosis are only partly understood. Disruption of the growth hormone (GH)-IGF-I axis seems to be closely associated with the development of liver disease, and treatment with recombinant human IGF (rhIGF)-I has been shown to halt, and even reverse, the fibrotic degeneration. IGF-I in itself has a strong antifibrotic effect that acts directly through the GH/IGF system and indirectly by the regulation of hepatoprotective and profibrogenic factors. It is most likely that IGF-I deficiency contributes to the diverse metabolic complications of cirrhosis. At present, liver transplantation remains the only efficient treatment of cirrhosis, and thus new methods of managing the disease are called for. RhIGF-I supplementation and IGF-I gene therapy may represent future perspectives of treatment.

Male hypogonadism in cirrhosis and after liver transplantation

Liver is deeply involved in the metabolism of proteins, hormones, enzymes, cytokines, as well as in sex hormones catabolism. Gonadal function requires a normal liver function, and it is well known that clinical signs of hypogonadism are common in patients with liver cirrhosis. Few studies have focused on hypothalamic- pituitary-gonadal alterations in male cirrhotic patients or after orthotopic liver transplantation (OLT). The pathogenesis of hypogonadism in cirrhotic patients is complex and not well explained. It involves both a gonadal and a hypothalamic- pituitary dysfunction. After OLT the hypothalamic-pituitary-gonadal function partially improves, showing that the hepatic dysfunction before OLT is deeply involved in its pathogenesis. After OLT some alterations persist in some patients, both because of pre-existing gonadal alterations (toxic-metabolic damage) and immunosuppressive pharmacological side effects. Further studies will explain the relationship between hypogonadism and OLT outcome, and the role of androgen therapy in hypogonadism after OLT, in the early months and in the long term.

Liver transduction with a simian virus 40 vector encoding insulin-like growth factor I reduces hepatic damage and the development of liver cirrhosis

Liver transplantation is the only treatment for advanced liver cirrhosis. Therapies halting the progression of the disease are urgently needed. Administration of recombinant insulin-like growth factor-I (rIGF-I) induces hepatoprotective effects in experimental cirrhosis. Therefore, we analyzed the efficacy of a recombinant simian virus 40 vector (rSV40) encoding IGF-I (rSVIGF-I) to prevent cirrhosis progression. First, transgene expression was evaluated in mice injected with rSV40 encoding luciferase, which showed long-term hepatic expression of the transgene. Interestingly, luciferase expression increased significantly in CCl(4)-damaged livers and upon IGF-I administration, thus liver injury and IGF-I expression from rSVIGF-I should favor transgene expression. rSVIGF-I therapeutic efficacy was studied in rats where liver cirrhosis was induced by CCl(4) inhalation during 36 weeks. At the end of the study, the hepatic levels of IGF-I and IGF-binding protein 3 were higher in rSVIGF-I-treated rats than in control cirrhotic animals. Cirrhotic rats treated with rSVIGF-I had reduced serum bilirubin, transaminases and liver fibrosis scores and increased hepatic expression of hepatocyte growth factor and STAT3alpha as compared to cirrhotic animals. Furthermore, cirrhotic animals showed testis atrophy and altered spermatogenesis, whereas testicular size and histology were normal in cirrhotic rats that received rSVIGF-I. Therefore, rSV40-mediated sustained expression of IGF-I in the liver slowed cirrhosis progression.

Clinical significance of serum IGF-I, IGF-II and IGFBP-3 in liver cirrhosis

AIM: To investigate the relationship between insulin-like growth factor-I, -II (IGF-I and IGF-II), IGF-binding protein 3 (IGFBP-3) and Child-Pugh score in patients with liver cirrhosis, and to search for potential clinical markers of liver function.

METHODS: Forty-four patients with advanced liver cirrhosis of viral origin were divided into 3 groups according to severity of cirrhosis (Child-Pugh score) and 38 healthy subjects served as controls. Serum levels of IGF-I, IGF-II and IGFBP-3 were measured by immunoradiometric assay.

RESULTS: Serum IGF-I, IGF-II and IGFBP-3 levels were significantly lower in patients with cirrhosis than in controls, and serum concentrations of IGF-I, IGF-II and IGFBP-3 were associated with the severity of liver dysfunction, and dropped sharply during the progression of liver failure. Among these 3 parameters, serum IGF-II was the most sensitive and effective indicator for liver dysfunction. Concentrations of IGF-I < 30 ng/mL, IGF-II < 200 ng/mL and IGFBP-3 < 6 ng/mL implied a negative prognosis for patients with liver cirrhosis.

CONCLUSION: Serum IGF-I, IGF-II and IGFBP-3 may provide a new dimension in the assessment of liver dysfunction. Combined detection of serum IGF-I, IGF-II and IGFBP-3 with Child-Pugh score is more effective in predicting prognosis than Child-Pugh score alone.

Growth hormone/insulin-like growth factor 1 axis recovery after liver transplantation: a preliminary prospective study

Many studies on cirrhotic patients have shown that insulin-like growth factor 1 (IGF-1) plasma levels are related to the severity of liver dysfunction. This result suggests that IGF-1 is probably useful for monitoring liver function in the perioperative course of orthotopic liver transplantation (OLT). Growth hormone (GH), IGF-1 plasma levels, and routine liver function tests were measured in 15 adult cirrhotic patients undergoing OLT. Measurements were made at the beginning of the operation; during OLT; 24 hours after reperfusion; and in the morning on days 7, 30, and 90. Twenty age-matched healthy volunteers with normal liver function served as controls. The study group had significantly higher GH levels and lower IGF-1 levels in the preoperative period compared with the controls. All patients achieved a complete functional hepatic recovery 1 month after OLT, although in 6 of them, the graft had an initial poor function (Group-IPF). GH and IGF-1 levels achieved near normal range within 1 week after OLT, and they had no significant correlations with other routine biochemistry tests in this period. IGF-1 levels in Group-IPF rose more slowly than in the group with a normal recovery of graft function. Surprisingly, 24 hours after reperfusion, IGF-1 levels were higher in Group-IPF than in the group with normal graft function. In conclusion, the severe GH/IGF-1 axis impairment found in patients with end-stage cirrhosis reverted very rapidly in the first days after successful OLT. Such a quick, postoperative modulation of IGF-1 plasma level by the graft suggests that this hormone has the potential to become one of the early indicators of post-OLT liver function recovery.

Ghrelin in chronic liver disease

BACKGROUND/AIMS

Ghrelin is a novel endogenous ligand for the growth hormone (GH) secretagogue receptor involved in energy metabolism, glucose homeostasis and food intake. We investigated the role of ghrelin and insulin-like growth factor-1 (IGF-1), the mediator of the GH axis, in patients with chronic liver diseases (CLD).

METHODS

Ghrelin and IGF-1 serum levels were determined in 105 CLD patients and 97 healthy controls and correlated with clinical and biochemical parameters.

RESULTS

Ghrelin was significantly elevated and IGF-1 reduced in CLD patients compared with healthy controls. IGF-1 serum levels inversely correlated with Child's classification. Ghrelin levels were significantly elevated in Child C cirrhosis patients independent of the aetiology of liver disease. Ghrelin levels did not correlate with liver function. In contrast, there was a correlation of ghrelin with clinical (gastrointestinal bleeding, ascites, encephalopathy) and biochemical (anaemia, inflammatory markers, hypoglycaemia, renal dysfunction) parameters. In a subgroup of patients with CLD and hepatocellular carcinoma (HCC), we observed a strong inverse correlation between alpha-fetoprotein (AFP) and ghrelin levels.

CONCLUSIONS

Unlike IGF-1, ghrelin is not correlated with liver function, but increases in Child C cirrhosis and with complications of CLD. The inverse correlation with AFP in HCC patients requires further studies on the potential impact of ghrelin on the pathogenesis of anorexia-cachexia syndrome.