Nerve growth factor involvement in liver cirrhosis and hepatocellular carcinoma

AIM: To define NGF (nerve growth factor) and its high- affinity receptor trkANGF presence and distribution in fibrotic liver and in HCC, and to verify if NGF might have a role in fibrosis and HCC. METHODS: Intracellular distribution of NGF and trkANGF were assessed by immunohistochemistry and immuno- electron microscopy in liver specimens from HCC, cirrhosis or both. ELISA was used to measure circulating NGF levels. RESULTS: NGF and trkANGF were highly expressed in HCC tissue, mainly localized in hepatocytes, endothelial and some Kupffer cells. In the cirrhotic part of the liver they were also markedly expressed in bile ducts epithelial and spindle-shaped cells. Surprisingly, in cirrhotic tissue from patients without HCC, both NGF and trkANGF were negative. NGF serum levels in cirrhotic and/or HCC patient were up to 25-fold higher than in controls. CONCLUSION: NGF was only detected in liver tissue with HCC present. Intracellular distribution suggests paracrine and autocrine mechanisms of action. Better definition of mechanisms may allow for therapeutic and diagnostic/prognostic use of NGF.

Pediatric nonalcoholic fatty liver disease:A clinical and laboratory challenge

The true prevalence of pediatric nonalcoholic fatty liver disease (NAFLD) is unknown. Challenges in determin ing the population prevalence of NAFLD include the type of test (and the reference intervals used to define normal and abnormal), the type of population (general population, hospital series), the demographic characteristics of the population sampled, and the nat ure of the study design. The natural history of pediat ric NAFLD remains uncertain. The issue of when to perform a liver biopsy in children with suspected NAFLD remains controversial. Children with NAFLD but normal alanine aminotransferase are rarely investigated. However, evidence of alterations in glucose metabolism parameters should prompt a better understanding of the natural history of pediatric NAFLD not only in terms of the progression of liver disease but also regarding its potential relationship with other health outcomes such as type 2 diabetes mellitus and cardiovascular disease. This evidence could make liver biopsy mandatory in the majority of cases at risk of progressive and severe hepatic and extrahepatic disease. This conclusion, however, raises the question of the feasibility of liver biopsy assessment in an extremely large at risk popul ation, and of the cost/effectiveness of this policy. There is a considerable, continuous interest in reliable, noninv asive alternatives that will allow the prognosis of pediat ric NAFLD to be followed in large community or populat ionbased studies.

DNA end binding activity and Ku70/80 heterodimer expression in human colorectal tumor

AIM: To determine the DNA binding activity and protein levels of the Ku70/80 heterodimer, the functional mediator of the NHEJ activity, in human colorectal carcinogenesis.METHODS: The Ku70/80 DNA-binding activity was determined by electrophoretic mobility shift assays in 20 colon adenoma and 15 colorectal cancer samples as well as matched normal colonic tissues. Nuclear and cytoplasmic protein expression was determined by immunohistochemistry and Western blot analysis.RESULTS: A statistically significant difference was found in both adenomas and carcinomas as compared to matched normal colonic mucosa (P＜0.00). However,changes in binding activity were not homogenous with approximately 50% of the tumors showing a clear increase in the binding activity, 30% displaying a modest increase and 15% showing a decrease of the activity.Tumors, with increased DNA-binding activity, also showed a statistically significant increase in Ku70 and Ku86nuclear expression, as determined by Western blot and immunohistochemical analyses (P＜0.001). Cytoplasmic protein expression was found in pathological samples,but not in normal tissues either from tumor patients or from healthy subjects.CONCLUSION: Overall, our DNA-binding activity and protein level are consistent with a substantial activation of the NHEJ pathway in colorectal tumors. Since the NHEJ is an error prone mechanism, its abnormal activation can result in chromosomal instability and ultimately lead to tumorigenesis.

Tissue with high intelligence quotient Adipose-derived stem cells in neural regeneration

The aim of the present review is to highlight the possible neuroregenerative potential ol adipose-derived stem cells. The key property of stem cells is plasticity including self-renewal, multilineage differentiation, and migration, whereas the required property is transplantability. For a long time, embryonic stem cells were thought to be the only source of pluripotency, a dogma that has been challenged during the last decade. Today, an alternative option might be adipose-derived stem cells, as easily accessible, ethical and autologous cellular source. Recent knowledge of adipobiology increasingly recognizes that adipose tissue is the major endo- and paracrine organ of the human body. Likewise, numerous neuropetides, neurotrophic factors, neurotransmitters, hypothalamic and steroid hormones and their receptors are shared by adipose tissue and brain. Accordingly, the regenerative potential of neuroprotective factor-secreting adipose-derived stem cells is outlined. Whether the possible benefits of adipose stem cell-based therapy may be mediated via cell transdifferentiation and/or paracrine mechanisms remains to further be evaluated.