The liver: a large endocrine gland

Beneficial and Deleterious Effects of Female Sex Hormones, Oral Contraceptives, and Phytoestrogens by Immunomodulation on the Liver

The liver is considered the laboratory of the human body because of its many metabolic processes. It accomplishes diverse activities as a mixed gland and is in continuous cross-talk with the endocrine system. Not only do hormones from the gastrointestinal tract that participate in digestion regulate the liver functions, but the sex hormones also exert a strong influence on this sexually dimorphic organ, via their receptors expressed in liver, in both health and disease. Besides, the liver modifies the actions of sex hormones through their metabolism and transport proteins. Given the anatomical position and physiological importance of liver, this organ is evidenced as an immune vigilante that mediates the systemic immune response, and, in turn, the immune system regulates the hepatic functions. Such feedback is performed by cytokines. Pro-inflammatory and anti-inflammatory cytokines are strongly involved in hepatic homeostasis and in pathological states; indeed, female sex hormones, oral contraceptives, and phytoestrogens have immunomodulatory effects in the liver and the whole organism. To analyze the complex and interesting beneficial or deleterious effects of these drugs by their immunomodulatory actions in the liver can provide the basis for either their pharmacological use in therapeutic treatments or to avoid their intake in some diseases.

Alteration of Trace Elements during Pathogenesis of N-Nitrosodimethylamine Induced Hepatic Fibrosis

The biochemical abnormalities and oxidative stress during pathogenesis of hepatic fibrosis could lead to alteration of trace elements. We studied the alteration of major trace elements during the pathogenesis of N-nitrosodimethylamine (NDMA)-induced hepatic fibrosis in rats. The biochemical and pathological indices of liver functions and hepatic fibrosis were evaluated. Serum and liver levels of copper, iron and zinc were determined using atomic absorption spectrophotometry. Cobalt, manganese, and molybdenum in the serum and liver were estimated by inductively coupled plasma mass spectrometry. Serial administrations of NDMA resulted in decreased serum albumin, biochemical abnormalities, increase of total liver collagen, and well-developed fibrosis and early cirrhosis. Serum and liver zinc content significantly decreased on all the days following NDMA administration. When copper and molybdenum markedly increased in the serum, liver molybdenum decreased dramatically. Both iron and manganese content significantly increased in the liver following NDMA-induced fibrosis. The results of the present study indicate that alteration of trace elements during pathogenesis of hepatic fibrosis is due to metabolic imbalance, biochemical abnormalities, decreased serum albumin, and ascites following NDMA-induced liver injury. The modulation of trace elements during hepatic fibrosis could play a prominent role in progression of the disease.

Molecular mechanisms in the pathogenesis of N-nitrosodimethylamine induced hepatic fibrosis

Hepatic fibrosis is marked by excessive synthesis and deposition of connective tissue proteins, especially interstitial collagens in the extracellular matrix of the liver. It is a result of an abnormal wound healing in response to chronic liver injury from various causes such as ethanol, viruses, toxins, drugs, or cholestasis. The chronic stimuli involved in the initiation of fibrosis leads to oxidative stress and generation of reactive oxygen species that serve as mediators of molecular events involved in the pathogenesis of hepatic fibrosis. These processes lead to cellular injury and initiate inflammatory responses releasing a variety of cytokines and growth factors that trigger activation and transformation of resting hepatic stellate cells into myofibroblast like cells, which in turn start excessive synthesis of connective tissue proteins, especially collagens. Uncontrolled and extensive fibrosis results in distortion of lobular architecture of the liver leading to nodular formation and cirrhosis. The perpetual injury and regeneration process could also results in genomic aberrations and mutations that lead to the development of hepatocellular carcinoma. This review covers most aspects of the molecular mechanisms involved in the pathogenesis of hepatic fibrosis with special emphasize on N-Nitrosodimethylamine (NDMA; Dimethylnitorsmaine, DMN) as the inducing agent.

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.

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.

Dietary supplementation of selenium in inorganic and organic forms differentially and commonly alters blood and liver selenium concentrations and liver gene expression profiles of growing beef heifers

In geographic regions where selenium (Se) soil concentrations are naturally low, the addition of Se to animal feed is necessary. Even though it is known that Se in grass and forage crops is primarily present in organic forms (especially as L-selenomethionine, L-selenocystine, and L-selenocystathionine), the feeding of Se in the naturally occurring organic selenium (OSe) compounds produces higher blood and tissue Se levels than the inorganic Se (ISe) salts, and that animal metabolism of OSe and ISe is fundamentally different. Se is commonly added in inorganic form as sodium selenite to cattle feeds because it is a less expensive source of supplemental Se then are OSe forms. A trial was conducted with growing cattle to determine if the addition of OSe versus ISe forms of Se in beef cattle feed produces differences in hepatic gene expression, thereby gaining insight into the metabolic consequence of feeding OSe versus ISe. Thirty maturing Angus heifers (261 ± 6 days) were fed a corn silage-based diet with no Se supplementation for 75 days. Heifers (body weight = 393 ± 9 kg) then were randomly assigned (n = 10) and fed Se supplements that contained none (control) or 3 mg Se/day in ISe (sodium selenite) or OSe (Sel-Plex®) form and enough of a common cracked corn/cottonseed hull-based diet (0.48 mg Se/day) to support 0.5 kg/day growth for 105 or 106 days. More Se was found in jugular whole blood and red blood cells and biopsied liver tissue of ISe and OSe treatment animals than control animals, and OSe animals contained more Se in these tissues than did ISe. Microarray and bioinformatic analyses of liver tissue gene expression revealed that the content of at least 80 mRNA were affected by ISe or OSe treatments, including mRNA associated with nutrient metabolism; cellular growth, proliferation, and immune response; cell communication or signaling; and tissue/organ development and function. Overall, three Se supplement-dependent gene groups were identified: ISe-dependent, OSe-dependent, and Se form-independent. More specifically, both forms of supplementation appeared to upregulate mitochondrial gene expression capacity, whereas gene expression of a protein involved in antiviral capacity was downregulated in ISe-supplemented animals, and OSe-supplemented animals had reduced levels of mRNA encoding proteins known to be upregulated during oxidative stress and cancerous states.

Effects of parenteral nutrition without and with growth hormone on growth hormone/insulin-like growth factor-1 axis after hepatectomy in hepatocellular carcinoma with liver cirrhosis

BACKGROUND

Complex alterations in the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis are thought to play an important role in the protein catabolism that complicates major surgical procedures. The aim of this study was to evaluate the potential roles of recombinant human growth hormone (rhGH) therapy after hepatectomy in hepatocellular carcinoma (HCC) with liver cirrhosis, and to investigate whether postoperative administration of rhGH increases the risk of tumor recurrences.

METHODS

Twenty-four patients with HCC in the setting of cirrhosis who underwent hepatectomy were randomly divided into 2 groups: parenteral nutrition (PN) group (n = 12) and rhGH + parenteral nutrition group (n = 12). Liver function, serum GH, IGF-1, and IGF binding protein-3 (IGFBP-3) were measured before operation, at postoperative days (POD) 1 and 6. IGF-1 and IGFBP-3 mRNA in liver tissue was measured by reverse transcriptase polymerase chain reaction. Liver Ki67 immunohistochemistry staining was studied. At the same time, 12 patients with cholelithiasis or liver hemangioma who underwent operation were segregated as a normal control.

RESULTS

On POD 6, compared with the PN group, serum prealbumin, GH, IGF-1, IGFBP-3, hepatic IGF-1 mRNA, IGFBP-3 mRNA, and liver Ki67 LI were higher in rhGH + PN group. The 6- and 12-month tumor-free survival rates, a median tumor-free survival time, were not different between the PN and rhGH + PN group.

CONCLUSIONS

rhGH + PN can ameliorate changes in the GH/IGF-1 axis after hepatectomy for HCC in the setting of cirrhosis.

Effects of parenteral nutrition with and without GH on the GH/IGF-1 axis after hepatectomy in hepatocellular carcinoma with liver cirrhosis

Postoperative hepatic insulin-like growth factor-1 (IGF-1) production may be severely disturbed in patients with liver cirrhosis. Complex alterations in the GH/IGF-1 axis are thought to play an important role in the protein catabolism that complicates major surgical procedures. The aim of this study was to explore the effects of parenteral nutrition (PN) with and without growth hormone (GH) on the GH/IGF-1 axis after hepatectomy for hepatocellular carcinoma (HCC) with cirrhosis and evaluate the potential roles of recombinant human GH (rhGH) therapy. Twenty-four patients with HCC with cirrhosis who underwent hepatectomy were randomly divided into two groups: a PN group (n = 12) and an rhGH + PN group (n = 12). Liver function, serum GH, IGF-1 and IGFBP-3 were measured before the operation and at post-operative days (POD) 1 and 6. Insulin-like growth factor-1 and IGFBP-3 mRNA in the liver tissue was detected by RT-PCR. The liver Ki67 immunohistochemistry staining was studied. At the same time, 12 patients with cholelithiasis or liver hemangioma who underwent operation served as normal control group. On POD 6, serum prealbumin, GH, IGF-1, IGFBP-3, hepatic IGF-1 mRNA, IGFBP-3 mRNA and liver Ki67 LI were higher in the rhGH + PN group than in the PN group. There was no significant difference in the 6-and 12-month tumor-free survival rate and the median tumor-free survival time between the PN group and the rhGH + PN group (P>0.05). These data indicate that rhGH + PN could ameliorate the changes in the GH/IGF-1 axis after hepatectomy for HCC in the setting of cirrhosis.

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.

The insulin-like growth factor binding protein 3 ternary complex is reduced in cirrhosis

BACKGROUND/AIMS

In healthy adults, serum insulin-like growth factor I (IGF-I), IGF binding protein 3 (IGFBP-3) and acid labile subunit (ALS) form a 150-kDa ternary complex under the control of growth hormone (GH). Approximately 80-90% of circulating IGF-I is bound to the ternary complex. In cirrhosis the GH/IGF axis is severely disturbed and the individual components of the ternary complex are reduced. However, the degree of ternary complex formation in cirrhosis has not previously been described.

METHODS

Serum IGF-I, IGFBP-3, ALS, the 150-kDa ternary complex and IGFBP-3 proteolysis were all measured in six compensated and six decompensated cirrhotic patients and compared to six healthy controls.

RESULTS

Patients with compensated cirrhosis had decreased levels of IGF-I (55%), IGFBP-3 (64%) and ALS (53%), and in the decompensated patients these levels were decreased even further: IGF-I (32%), IGFBP-3 (37%) and ALS (27%) compared to healthy controls. The levels of the ternary complex followed this pattern, with low levels seen in the compensated patients (66%) and a further reduction in the decompensated patients (27%). Ternary complex levels correlated negatively with the Child-Pugh score. No increase in IGFBP-3 proteolysis was found in cirrhotic patients compared to healthy controls.

CONCLUSION

Cirrhosis is associated with reduced levels of the 150-kDa ternary IGFBP-3 complex correlating with the degree of liver disease.