Cytokeratin-19 positivity is acquired along cancer progression and does not predict cell origin in rat hepatocarcinogenesis

Although the expression of the stem/progenitor cell marker cytokeratin-19 (CK-19) has been associated with the worst clinical prognosis among all HCC subclasses, it is yet unknown whether its presence in HCC is the result of clonal expansion of hepatic progenitor cells (HPCs) or of de-differentiation of mature hepatocytes towards a progenitor-like cell phenotype. We addressed this question by using two rat models of hepatocarcinogenesis: the Resistant-Hepatocyte (R-H) and the Choline-methionine deficient (CMD) models. Our data indicate that the expression of CK-19 is not the result of a clonal expansion of HPCs (oval cells in rodents), but rather of a further step of preneoplastic hepatocytes towards a less differentiated phenotype and a more aggressive behavior. Indeed, although HCCs were positive for CK-19, very early preneoplastic foci (EPFs) were completely negative for this marker. While a few weeks later the vast majority of preneoplastic nodules remained CK-19 negative, a minority became positive, suggesting that CK-19 expression is the result of de-differentiation of a subset of EPFs, rather than a marker of stem/progenitor cells. Moreover, the gene expression profile of CK-19-negative EPFs clustered together with CK-19-positive nodules, but was clearly distinct from CK-19 negative nodules and oval cells. Conclusion: i) CK-19-positive cells are not involved in the early clonal expansion observed in rat hepatocarcinogenesis; ii) CK-19 expression arises in preneoplastic hepatocyte lesions undergoing malignant transformation; iii) CK-19 positivity in HCCs does not necessarily reflect the cell of origin of the tumor, but rather the plasticity of preneoplastic cells during the tumorigenic proces

Biomass supply for energetic purposes from some Cardueae species grown in Mediterranean farming systems

"In order to explore complementary biomass sources, field studies were conducted on Cynara cardunculus botanical varieties (globe artichoke and cultivated cardoon) for energy purposes. In addition, the potential of milk thistle (Silybum marianum L. Gaertn.) as a suitable energy crop for Southern Europe countries was investigated. The three different crops were compared over three years (2007-2010) in a Mediterranean environment (Sardinia, Southern Italy) for quantitative and qualitative (calorific value, ultimate and proximate analyses, ash composition) biomass characteristics. Annual biomass production across years averaged about 10, 4, and 16 Mg ha(-1) in cardoon, globe artichoke and milk thistle, respectively. The chemical analysis of biomass showed a similar composition among crops with a mean ash content of 14% and a higher calorific value of about 17 MJ kg(-1). Annual energy yield ranged between 64 GJ ha(-1) reached by globe artichoke and 275 GJ ha(-1) reached in milk thistle. The exploitation of globe artichoke crop residues for energetic purpose can represent a complementary income for farmers. The present study confirms the good biomass yield of cardoon in cultivation systems characterized by limited water input and indicate milk thistle as a promising crop for biomass production. Future work is necessary in order to investigate different genotypes of the three crops for potential biomass and grain yield and their chemical composition, to detect agronomic practices suitable to optimize qualitative crops performances and to set up specific cropping systems. (c) 2013 Elsevier B.V. All rights reserved.

LCA study of oleaginous bioenergy chains in a Mediterranean environment

This paper reports outcomes of life cycle assessments (LCAs) of three different oleaginous bioenergy chains (oilseed rape, Ethiopian mustard and cardoon) under Southern Europe conditions. Accurate data on field practices previously collected during a three-year study at two sites were used. The vegetable oil produced by oleaginous seeds was used for power generation in medium-speed diesel engines while the crop residues were used in steam power plants. For each bioenergy chain the environmental impact related to cultivation, transportation of agricultural products and industrial conversion for power generation was evaluated by calculating cumulative energy demand, acidification potential and global warming potential. For all three bioenergy chains, the results of the LCA study show a considerable saving of primary energy (from 70 to 86 GJ ha-1) and greenhouse gas emissions (from 4.1 to 5.2 t CO2 ha-1) in comparison to power generation from fossil fuels, although the acidification potential of these bioenergy chains may be twice that of conventional power generation. In addition, the study highlights that land use changes due to the cultivation of the abovementioned crops reduce soil organic content and therefore worsen and increase greenhouse gas emissions for all three bioenergy chains. The study also demonstrates that the exploitation of crop residues for energy production greatly contributes to avoid environmental impact of the three bioenergy chains

Alpha-lipoic acid promotes the growth of rat hepatic preneoplastic lesions in the choline deficient model

alpha-lipoic acid (alpha-LA) is an antioxidant used in a number of conditions related to liver diseases. Herein, we investigated the effect of alpha-LA on the development of rat pre-neoplastic lesions generated by a model of hepatocarcinogenesis, which has similarities in its histopathological sequence to human hepatocellular carcinoma development with cirrhosis. Initiation of hepatocytes was achieved by treatment with a single dose of diethylnitrosamine and promotion by feeding a choline-methionine-deficient diet (CMD), with or without alpha-LA. Pre-neoplastic lesions were identified by their positivity to the placental form of glutathione S-transferase (GSTP) or to gamma glutamyl transpeptidase. alpha-LA given to rats fed a CMD for 6 weeks dramatically increased the number of GSTP-positive foci as compared with rats fed a CMD alone (96/cm(2) versus 7/cm(2)), the mean foci area (0.033 versus 0.008 mm(2)) and the percentage of GSTP-positive liver tissue (3.01 versus 0.07%). Essentially similar results were obtained after 10 weeks of treatment. Co-treatment with CMD + alpha-LA also resulted in the enhancement of fat accumulation, lipid peroxidation and hepatocyte death; increased expression of tumor necrosis factor-alpha, cytochrome 2E1 and cyclooxygenase-2, enhanced activation of c-jun N-terminal kinase and signal transducer activator of transcription 3, and chronic hepatocyte proliferation was also observed. No such effects were observed when alpha-LA was added to a choline-supplemented diet. In conclusion, administration of alpha-LA in conditions associated with hepatic damage aggravates liver injury and stimulates the development of pre-neoplastic lesions; the results also suggest caution in its use in the presence of chronic liver injur

Combined effects of microenvironment and land use on C fluxes in a Mediterranean agro-silvopastoral system

none7noAppropriate agroforestry practices might contribute to carbon sequestration and cope with climate change by modulating ecosystem services. It is known that land use change might affect soil-atmosphere carbon dioxide (CO2) effluxes of agro-silvopastoral systems. However, little information is available at single microenvironment level. Across four years, fortnightly measurements of soil respiration were carried out at different microenvironment (beneath tree cover vs open areas) and land use (native understorey vs its conversion into improved pasture) within a high-density evergreen cork oak forest of Sardinia (Italy). We also monitored aboveground dry matter yields and soil carbon stocks. Measurements revealed that the two investigated microenvironments widely differed for the amounts of photosynthetically active radiation and microclimatic traits such as soil water content, air humidity, soil and air temperature. High seasonal and inter-annual variability in soil respiration rates was recorded (range 0.3–12.6 CO2 μmol m−2 s-1) and the peak values were reached in the summer of the third year in the improved pasture beneath tree cover. The conversion of the native understorey into improved pasture beneath cork oak increased significantly the annual cumulative soil respiration for three consecutive years, reaching values of about 71, 36 and 100 t CO2 ha−1 yr−1, which were from 38 to 88 % higher than the remaining treatments. On average, heterotrophic component represented from 68–76% of soil respiration. An extreme drought event, which was emblematic of a climate change context, was experienced in the second year. It countered the increase in the heterotrophic component of soil respiration and minimized up to 20-fold the forage on offer from pasture swards. Based on measured CO2 effluxes, the study demonstrated that the effects of the land use change at the microenvironment beneath tree cover were substantially unbalanced in terms of soil organic carbon stocks. Therefore, results suggest avoiding the soil mechanical disturbance beneath cork oak in the investigated ecosystem to reduce anthropogenic carbon fluxes to the atmosphere.mixedSanna F.; Campesi G.; Deligios P.; Ledda L.; Piluzza G.; Sulas L.; Re G.A.Sanna, F.; Campesi, G.; Deligios, P.; Ledda, L.; Piluzza, G.; Sulas, L.; Re, G. A

Inoculation and N fertilization affect the dry matter, N fixation, and bioactive compounds in Sulla leaves

Sulla (Sulla coronaria [L.] Medik), a Mediterranean short-lived legume with tolerance to drought-prone environments, requires inoculation outside its natural habitat. Its leaves are appreciated for the bromatological composition and content of bioactive compounds. However, no information is available regarding the distinct effects of inoculation and nitrogen (N) applications on leaf dry matter (DM), fixed N, and bioactive compounds. Sulla leaves were sampled from the vegetative stage to seed set in Sardinia (Italy) during 2013–2014 and leaf DM, N content, and fixed N were determined. Compared to the best performing inoculated treatments, DM yield and fixed N values of the control only represented 8% to 20% and 2% to 9%, respectively. A significant relationship between fixed N and leaf DM yield was established, reaching 30 kg fixed N t–1 at seed set. Significant variations in leaf atom% 15N excess and %Ndfa quantified decreases in leaf N fixation coupled with N application. Moreover, the petiole content of phenolic compounds markedly increased in the uninoculated control, suggesting deeper investigations on the relationship between bioactive compounds and inoculation treatments. Results highlighted substantial variation in DM, N yields, N-fixation ability, and content of bioactive compounds of sulla leaves caused by inoculation and N fertilization