Publications by authors named "Fabio Marongiu"

51 Publications

Aging and Cancer: The Waning of Community Bonds.

Cells 2021 Aug 31;10(9). Epub 2021 Aug 31.

Department of Biomedical Sciences, University of Cagliari, 09124 Cagliari, Italy.

Cancer often arises in the context of an altered tissue landscape. We argue that a major contribution of aging towards increasing the risk of neoplastic disease is conveyed through effects on the microenvironment. It is now firmly established that aged tissues are prone to develop clones of altered cells, most of which are compatible with a normal histological appearance. Such increased clonogenic potential results in part from a generalized decrease in proliferative fitness, favoring the emergence of more competitive variant clones. However, specific cellular genotypes can emerge with reduced cooperative and integrative capacity, leading to disruption of tissue architecture and paving the way towards progression to overt neoplastic phenotypes.
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http://dx.doi.org/10.3390/cells10092269DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8468626PMC
August 2021

Cell competition, cooperation, and cancer.

Neoplasia 2021 Sep 6;23(10):1029-1036. Epub 2021 Sep 6.

Department of Biomedical Sciences, University of Cagliari, Italy. Electronic address:

Complex multicellular organisms require quantitative and qualitative assessments on each of their constitutive cell types to ensure coordinated and cooperative behavior towards overall functional proficiency. Cell competition represents one of the operating arms of such quality control mechanisms and relies on fitness comparison among individual cells. However, what is exactly included in the fitness equation for each cell type is still uncertain. Evidence will be discussed to suggest that the ability of the cell to integrate and collaborate within the organismal community represents an integral part of the best fitness phenotype. Thus, under normal conditions, cell competition will select against the emergence of altered cells with disruptive behavior towards tissue integrity and/or tissue pattern formation. On the other hand, the winner phenotype prevailing as a result of cell competition does not entail, by itself, any degree of growth autonomy. While cell competition per se should not be considered as a biological driving force towards the emergence of the neoplastic phenotype, it is possible that the molecular machinery involved in the winner/loser interaction could be hijacked by evolving cancer cell populations.
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http://dx.doi.org/10.1016/j.neo.2021.08.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8429595PMC
September 2021

Long-term moderate caloric restriction and social isolation synergize to induce anorexia-like behavior in rats.

Nutrition 2021 06 2;86:111177. Epub 2021 Feb 2.

Department of Biomedical Sciences - Unit of Experimental Medicine, University of Cagliari, Cagliari, Italy. Electronic address:

Moderate caloric restriction (CR) is an effective strategy to delay the onset of chronic disease states. Conversely, social isolation (SI) carries an increased risk of morbidity and mortality from several causes. The present studies were designed to investigate the long-term effect of the two combined exposures. Two-month-old male rats of the Fischer 344 strain were fed either ad libitum or under a regimen of CR, and each of the two animal sets were housed either in group or isolation. Food consumption and animal growth curves were as expected during the first 6 wk of observation. However, starting at 2 mo and continuing until the fifth month of follow up, rats exposed to both CR and SI showed signs of altered feeding behavior and were unable to complete their (already restricted) meal. Furthermore, altered behavior was accompanied by a corresponding decrease in growth rate until no further increase in body weight was observed. Restoration of group-housing conditions led to a reversal of this phenotype. We conclude that chronic moderate CR and SI synergize to induce anorexia-like behavior, representing a simple and reproducible model to study such an eating disorder.
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http://dx.doi.org/10.1016/j.nut.2021.111177DOI Listing
June 2021

Cell competition in liver carcinogenesis.

World J Hepatol 2020 Aug;12(8):475-484

Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari, Cagliari 09124, Italy.

Cell competition is now a well-established quality control strategy to optimize cell and tissue fitness in multicellular organisms. While pursuing this goal, it is also effective in selecting against altered/defective cells with putative (pre)-neoplastic potential, thereby edging the risk of cancer development. The flip side of the coin is that the molecular machinery driving cell competition can also be co-opted by neoplastic cell populations to expand unchecked, outside the boundaries of tissue homeostatic control. This review will focus on information that begins to emerge regarding the role of cell competition in liver physiology and pathology. Liver repopulation by normal transplanted hepatocytes is an interesting field of investigation in this regard. The biological coordinates of this process share many features suggesting that cell competition is a driving force for the clearance of endogenous damaged hepatocytes by normal donor-derived cells, as previously proposed. Intriguing analogies between liver repopulation and carcinogenesis will be briefly discussed and the potential dual role of cell competition, as a barrier or a spur to neoplastic development, will be considered. Cell competition is in essence a cooperative strategy organized at tissue level. One facet of such cooperative attitude is expressed in the elimination of altered cells which may represent a threat to the organismal community. On the other hand, the society of cells can be disrupted by the emergence of selfish clones, exploiting the molecular bar codes of cell competition, thereby paving their way to uncontrolled growth.
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http://dx.doi.org/10.4254/wjh.v12.i8.475DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7475782PMC
August 2020

Differential response to hepatic differentiation stimuli of amniotic epithelial cells isolated from four regions of the amniotic membrane.

J Cell Mol Med 2020 04 6;24(7):4350-4355. Epub 2020 Mar 6.

Department of Medicine and Ageing Sciences, Gabriele D'Annunzio University of Chieti-Pescara, Chieti, Italy.

Human Amniotic Epithelial Cells (hAEC) isolated from term placenta are a promising source for regenerative medicine. However, it has long been debated whether the hAEC population consists of heterogeneous or homogeneous cells. In a previous study, we investigated the characteristics of hAEC isolated from four different regions of the amniotic membrane finding significant heterogeneity. The aim of this study was to evaluate the hepatic differentiation capability of hAEC isolated from these four regions. Human term placentae were collected after caesarean section and hAEC were isolated from four regions of the amniotic membrane (R1-R4, according to their relative distance from the umbilical cord) and treated in hepatic differentiation conditions for 14 days. hAEC-derived hepatocyte-like cells showed marked differences in the expression of hepatic markers: R4 showed higher levels of Albumin and Hepatocyte Nuclear Factor (HNF) 4α whereas R1 expressed higher Cytochrome P450 enzymes, both at the gene and protein level. These preliminary results suggest that hAEC isolated from R1 and R4 of the amniotic membrane are more prone to hepatic differentiation. Therefore, the use of hAEC from a specific region of the amniotic membrane should be taken into consideration as it could have an impact on the outcome of therapeutic applications.
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http://dx.doi.org/10.1111/jcmm.14928DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7171396PMC
April 2020

Cancer as a disease of old age: changing mutational and microenvironmental landscapes.

Br J Cancer 2020 03 11;122(7):943-952. Epub 2020 Feb 11.

Department of Biochemistry and Molecular Genetics, Integrated Department of Immunology, Department of Pediatrics, Department of Medicine (Section of Hematology), University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.

Why do we get cancer mostly when we are old? According to current paradigms, the answer is simple: mutations accumulate in our tissues throughout life, and some of these mutations contribute to cancers. Although mutations are necessary for cancer development, a number of studies shed light on roles for ageing and exposure-dependent changes in tissue landscapes that determine the impact of oncogenic mutations on cellular fitness, placing carcinogenesis into an evolutionary framework. Natural selection has invested in somatic maintenance to maximise reproductive success. Tissue maintenance not only ensures functional robustness but also prevents the occurrence of cancer through periods of likely reproduction by limiting selection for oncogenic events in our cells. Indeed, studies in organisms ranging from flies to humans are revealing conserved mechanisms to eliminate damaged or oncogenically initiated cells from tissues. Reports of the existence of striking numbers of oncogenically initiated clones in normal tissues and of how this clonal architecture changes with age or external exposure to noxious substances provide critical insight into the early stages of cancer development. A major challenge for cancer biology will be the integration of these studies with epidemiology data into an evolutionary theory of carcinogenesis, which could have a large impact on addressing cancer risk and treatment.
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http://dx.doi.org/10.1038/s41416-019-0721-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7109142PMC
March 2020

Aging and Caloric Restriction Modulate the DNA Methylation Profile of the Ribosomal RNA Locus in Human and Rat Liver.

Nutrients 2020 Jan 21;12(2). Epub 2020 Jan 21.

IRCCS Istituto delle Scienze Neurologiche di Bologna, 40 139 Bologna, Italy.

A growing amount of evidence suggests that the downregulation of protein synthesis is an adaptive response during physiological aging, which positively contributes to longevity and can be modulated by nutritional interventions like caloric restriction (CR). The expression of ribosomal RNA (rRNA) is one of the main determinants of translational rate, and epigenetic modifications finely contribute to its regulation. Previous reports suggest that hypermethylation of ribosomal DNA (rDNA) locus occurs with aging, although with some species- and tissue- specificity. In the present study, we experimentally measured DNA methylation of three regions (the promoter, the 5' of the 18S and the 5' of 28S sequences) in the rDNA locus in liver tissues from rats at two, four, 10, and 18 months. We confirm previous findings, showing age-related hypermethylation, and describe, for the first time, that this gain in methylation also occurs in human hepatocytes. Furthermore, we show that age-related hypermethylation is enhanced in livers of rat upon CR at two and 10 months, and that at two months a trend towards the reduction of rRNA expression occurs. Collectively, our results suggest that CR modulates age-related regulation of methylation at the rDNA locus, thus providing an epigenetic readout of the pro-longevity effects of CR.
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http://dx.doi.org/10.3390/nu12020277DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7070571PMC
January 2020

Fecal Metaproteomic Analysis Reveals Unique Changes of the Gut Microbiome Functions After Consumption of Sourdough Bread.

Front Microbiol 2019 30;10:1733. Epub 2019 Jul 30.

Department of Biomedical Sciences, University of Sassari, Sassari, Italy.

Sourdough-leavened bread (SB) is acknowledged for its great variety of valuable effects on consumer's metabolism and health, including a low glycemic index and a reduced content of the possible carcinogen acrylamide. Here, we aimed to investigate how these effects influence the gut microbiota composition and functions. Therefore, we subjected rats to a diet supplemented with SB, baker's yeast leavened bread (BB), or unsupplemented diet (chow), and, after 4 weeks of treatment, their gut microbiota was analyzed using a metaproteogenomic approach. As a result, diet supplementation with SB led to a reduction of specific members of the intestinal microbiota previously associated to low protein diets, namely and , or known as intestinal pathobionts, i.e., . Concerning functions, asparaginases expressed by were observed as more abundant in SB-fed rats, leading to hypothesize that in their colonic microbiota the enzyme substrate, asparagine, was available in higher amounts than in BB- and chow-fed rats. Another group of protein families, expressed by , was detected as more abundant in animal fed SB-supplemented diet. Of these, manganese catalase, small acid-soluble proteins (SASP), Ser/Thr kinase PrkA, and V-ATPase proteolipid subunit have been all reported to take part in sporulation, strongly suggesting that the diet supplementation with SB might promote environmental conditions inducing metabolic dormancy of spp. within the gut microbiota. In conclusion, our data describe the effects of SB consumption on the intestinal microbiota taxonomy and functions in rats. Moreover, our results suggest that a metaproteogenomic approach can provide evidence of the interplay between metabolites deriving from bread digestion and microbial metabolism.
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http://dx.doi.org/10.3389/fmicb.2019.01733DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6682701PMC
July 2019

Time-restricted feeding delays the emergence of the age-associated, neoplastic-prone tissue landscape.

Aging (Albany NY) 2019 06;11(11):3851-3863

Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy.

Aging increases the risk of cancer partly through alterations in the tissue microenvironment. Time-restricted feeding (TRF) is being proposed as an effective strategy to delay biological aging. In the present studies, we assessed the effect of long-term exposure to TRF on the emergence of the age-associated, neoplastic-prone tissue landscape. Animals were exposed to either feeding (ALF) or TRF for 18 months and then transplanted with hepatocytes isolated from pre-neoplastic nodules. Both groups were continued ALF and the growth of transplanted cells was evaluated 3 months later. A significant decrease in frequency of larger size clusters of pre-neoplastic hepatocytes was seen in TRF-exposed group compared to controls. Furthermore, TRF modified several parameters related to both liver and systemic aging towards the persistence of a younger phenotype, including a decrease in liver cell senescence, diminished fat accumulation and up-regulation of SIRT1 in the liver, down-regulation of plasma IGF-1, decreased levels of plasma lipoproteins and up-regulation of hippocampal brain-derived growth factor (BDNF).These results indicate that TRF was able to delay the onset of the neoplastic-prone tissue landscape typical of aging. To our knowledge, this is the first investigation to describe a direct beneficial effect of TRF on early phases of carcinogenesis.
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http://dx.doi.org/10.18632/aging.102021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6594823PMC
June 2019

Caloric restriction promotes functional changes involving short-chain fatty acid biosynthesis in the rat gut microbiota.

Sci Rep 2018 10 3;8(1):14778. Epub 2018 Oct 3.

Porto Conte Ricerche, Science and Technology Park of Sardinia, Tramariglio, Alghero, Italy.

Caloric restriction (CR) is known to promote health and longevity, likely via modification of the gut microbiota (GM). However, functional and metabolic changes induced in the GM during CR are still unidentified. Here, we investigated the short- and long-term effects of CR on the rat GM using a metaproteogenomic approach. We show that a switch from ad libitum (AL) low fat diet to CR in young rats is able to induce rapid and deep changes in their GM metaproteomic profile, related to a reduction of the Firmicutes/Bacteroidetes ratio and an expansion of lactobacilli. Specifically, we observed a significant change in the expression of the microbial enzymes responsible for short-chain fatty acid biosynthesis, with CR boosting propionogenesis and limiting butyrogenesis and acetogenesis. Furthermore, these CR-induced effects were maintained up to adulthood and started to be reversed after a short-term diet change. We also found that CR alters the abundance of an array of host proteins released in stool, mainly related to epithelial barrier integrity and inflammation. Hence, our results provide thorough information about CR-induced modifications to GM and host functional activity, and might constitute the basis for novel GM-based approaches aimed at monitoring the effectiveness of dietary interventions.
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http://dx.doi.org/10.1038/s41598-018-33100-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6170429PMC
October 2018

Development versus Evolution in Cancer Biology.

Trends Cancer 2018 05 7;4(5):342-348. Epub 2018 Apr 7.

Unit of Experimental Medicine, Department of Biomedical Sciences, University of Cagliari, Via Porcell 4, 09124 Cagliari, Italy. Electronic address:

The terms 'development' and 'evolution' are both used to describe the unfolding of the carcinogenic process. However, there is increasing awareness of an essential difference in the meanings of these two terms with reference to cancer. We discuss evidence suggesting that the concepts of development and evolution are both pertinent to the description of carcinogenesis; however, they appropriately apply to distinct phases of a multistep process. Such a distinction bears important implications for the study and management of cancer.
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http://dx.doi.org/10.1016/j.trecan.2018.03.007DOI Listing
May 2018

Evidence of Amniotic Epithelial Cell Differentiation toward Hepatic Sinusoidal Endothelial Cells.

Cell Transplant 2018 01;27(1):23-30

1 Experimental Medicine Unit, Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy.

Amniotic epithelial cells (AECs) represent a useful and noncontroversial source for liver-based regenerative medicine, as they can differentiate into hepatocytes upon transplantation into the liver. However, the possibility that AECs can differentiate into other liver cell types, such as hepatic sinusoidal endothelial cells (HSECs), has never been assessed. In order to test this hypothesis, rat- and human-derived AECs (rAECs and hAECs, respectively) were subjected to endothelial cell tube formation assay in vitro. Moreover, to evaluate differentiation in vivo, the retrorsine (RS) model of liver repopulation was used. Pyrrolizidine alkaloids (including RS) are known to target both hepatocytes and endothelial cells, inducing cell enlargement and inhibition of cell cycle progression. rAECs and hAECs were able to form capillary-like structures when cultured under proangiogenic conditions. For in vivo experiments, rAECs were obtained from dipeptidyl peptidase type IV (DPP-IV, CD26) donors and were transplanted into the liver of recipient CD26 negative animals pretreated with RS. rAEC-derived cells were engrafted in between hepatocytes and resembled HSECs as assessed by morphological analysis and the pattern of expression of CD26. Donor-derived CD26 cells coexpressed HSEC markers RECA-1 and SE-1, while they lacked expression of typical hepatocyte markers (i.e., cytochrome P450, hepatocyte nuclear factor 4α). As such, these results provide the first evidence that AECs can respond to proangiogenic signals in vitro and differentiate into HSECs in vivo. Furthermore, they support the conclusion that AECs possesses great plasticity and represents a promising tool in the field of regenerative medicine both in the liver and in other organs.
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http://dx.doi.org/10.1177/0963689717727541DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6434484PMC
January 2018

[Accurate compiling of the hospital discharge records according to clinicians' perception: critical issues and perspectives].

Epidemiol Prev 2018 Jan-Feb;42(1):34-39

Azienda ospedaliero-universitaria, Cagliari.

Objectives: to explore clinicians vision on hospital discharge records in order to identify useful elements to foster a more accurate compiling.

Design: qualitative research with phenomenological approach.

Setting And Participants: participants were selected through purposive sampling among clinicians of two hospitals located in Sardinia; the sample included 76 people (32 medical directors and 44 doctors in training).

Main Outcome Measures: identified codes for themes under investigation: vision of accurate compiling, difficulties, and proposals.

Results: collected data highlighted two prevailing visions, respectively focused on the importance of an accurate compiling and on the burden of such activity. The accurate compiling is hindered by the lack of motivation and training, by the limits of the registration system and the information technology, by the distortions induced by the prominent role of the hospital discharge records in the evaluation processes. Training, timely updating of the information system accompanied by a proper cross-cultural validation process, improvement of the computer system, and activation of support services could promote more accurate compiling.

Conclusions: the implementation of services, unconnected with evaluation and control processes, dedicated to training and support in the compiling of the hospital discharge records and in the conduction of related epidemiological studies would facilitate the compliance to the compilation. Such services will make tangible the benefits obtainable from this registration system, increasing skills, motivation, ownership, and facilitating greater accuracy in compiling.
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http://dx.doi.org/10.19191/EP18.1.P034.013DOI Listing
March 2019

Regenerative Medicine: Shedding Light on the Link between Aging and Cancer.

Cell Transplant 2017 09;26(9):1530-1537

1 Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari, Cagliari, Italy.

The evidence linking aging and cancer is overwhelming. Findings emerging from the field of regenerative medicine reinforce the notion that aging and cancer are profoundly interrelated in their pathogenetic pathways. We discuss evidence to indicate that age-associated alterations in the tissue microenvironment contribute to the emergence of a neoplastic-prone tissue landscape, which is able to support the selective growth of preneoplastic cell populations. Interestingly, tissue contexts that are able to select for the growth of preneoplastic cells, including the aged liver microenvironment, are also supportive for the clonal expansion of normal, homotypic, transplanted cells. This suggests that the growth of normal and preneoplastic cells is possibly driven by similar mechanisms, implying that strategies based on principles of regenerative medicine might be applicable to modulate neoplastic disease.
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http://dx.doi.org/10.1177/0963689717721224DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5680953PMC
September 2017

A GC-MS untargeted metabolomics analysis in the plasma and liver of rats lacking dipeptidyl-peptidase type IV enzyme activity.

J Physiol Biochem 2017 Nov 11;73(4):575-582. Epub 2017 Sep 11.

Dipartimento di Scienze Biomediche, Università degli Studi di Cagliari, Via Porcell 4, 09124, Cagliari, Italy.

This study was achieved with the aim to find metabolic changes between Fischer rats with different dipeptidyl peptidase-type 4 (DPPIV) expression. The DPPIV is an enzyme expressed in several tissues and is critically involved in the regulation of meal-related insulin secretion in healthy individuals. The metabolic consequences of chronic DPPIV inhibition were analyzed in a surrogate animal model of genetic enzyme deficiency. Hyphenated gas chromatography-mass spectrometry (GC-MS) and multivariate data analysis techniques were used to study the metabolic aqueous fraction profile of 18 plasma and liver samples in two syngeneic rat strains differing in DPPIV activity (DPPIV vs. DPPIV). The hyperglycemic response following oral glucose administration was attenuated in DPPIV rats, as expected. Statistical significant differences between the two strains were observed among the low molecular weight polar metabolites analyzed from plasma and liver.These included a decrease in malic acid and glutamine and an increase in pyroglutamic acid, serine, and alanine in plasma of DPPIV rats. In addition, palmitic acid, L-proline, and ribitol were decreased in the liver of DPPIV strain. Such alterations were compatible with a normal phenotype. These results suggest that long-term exposure to DPPIV inhibitors looks compatible with an overall balanced metabolism.
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http://dx.doi.org/10.1007/s13105-017-0588-7DOI Listing
November 2017

Caloric restriction promotes rapid expansion and long-lasting increase of Lactobacillus in the rat fecal microbiota.

Gut Microbes 2018 03 21;9(2):104-114. Epub 2017 Sep 21.

a Porto Conte Ricerche , Science and Technology Park of Sardinia , Tramariglio, Alghero , Italy.

Previous studies indicated that caloric restricted diet enables to lower significantly the risk of cardiovascular and metabolic diseases. In experimental animal models, life-long lasting caloric restriction (CR) was demonstrated to induce changes of the intestinal microbiota composition, regardless of fat content and/or exercise. To explore the potential impact of short and long-term CR treatment on the gut microbiota, we conducted an analysis of fecal microbiota composition in young and adult Fisher 344 rats treated with a low fat feed under ad libitum (AL) or CR conditions (70%). We report here significant changes of the rat fecal microbiota that arise rapidly in young growing animals after short-term administration of a CR diet. In particular, Lactobacillus increased significantly after 8 weeks of CR treatment and its relative abundance was significantly higher in CR vs AL fed animals after 36 weeks of dietary intervention. Taken together, our data suggest that Lactobacillus intestinal colonization is hampered in AL fed young rats compared to CR fed ones, while health-promoting CR diet intervention enables the expansion of this genus rapidly and persistently up to adulthood.
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http://dx.doi.org/10.1080/19490976.2017.1371894DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5989789PMC
March 2018

Caloric restriction delays early phases of carcinogenesis via effects on the tissue microenvironment.

Oncotarget 2017 May;8(22):36020-36032

Department of Biomedical Sciences, Unit of Experimental Medicine University of Cagliari-Italy, Cagliari, Italy.

Caloric restriction (CR) is an effective and consistent means to delay aging and the incidence of chronic diseases related to old age, including cancer. However, the precise mechanisms responsible for the beneficial effect of CR on carcinogenic process are yet to be identified.In the present studies the hypothesis was tested that the CR might delay carcinogenesis via modulatory effects exerted on the age-associated, neoplastic-prone tissue microenvironment. Using a well characterized, orthotopic cell transplantation (Tx) system in the rat, preneoplastic hepatocytes isolated from liver nodules were injected into either old syngeneic rats fed ad libitum (AL) or animals of the same age given a CR diet (70% of AL feeding). Analysis of donor-derived cell clusters performed at 10 weeks post-Tx revealed a significant shift towards smaller class sizes in the group receiving CR diet. Clusters comprising more than 50 cells, including large hepatic nodules, were thrice more frequent in AL vs. CR animals. Incidence of spontaneous endogenous nodules was also decreased by CR. Markers of cell senescence were equally expressed in the liver of AL and CR groups. However, higher levels of SIRT1 and FOXO1 proteins were detected in CR-exposed livers, while expression of HDAC1 and C/EBPβ were decreased. These results are interpreted to indicate that CR delays the emergence of age-associated neoplastic disease through effects exerted, at least in part, on the tissue microenvironment. Nutrient-sensing pathways might mediate such modulatory effect.
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http://dx.doi.org/10.18632/oncotarget.16421DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5482635PMC
May 2017

Differentiation of amniotic epithelial cells into various liver cell types and potential therapeutic applications.

Placenta 2017 Nov 30;59:139-145. Epub 2017 Mar 30.

University of Cagliari, Department of Biomedical Sciences, Unit of Experimental Medicine, Cagliari, Italy. Electronic address:

The aim of Regenerative Medicine is to replace or regenerate human cells, tissues or organs in order to restore normal function. Among all organs, the liver is endowed with remarkable regenerative capacity. Nonetheless, there are conditions in which this ability is impaired, and the use of isolated cells, including stem cells, is being considered as a possible therapeutic tool for the management of chronic hepatic disease. Placenta holds great promise for the field of regenerative medicine. It has long been used for the treatment of skin lesions and in ophthalmology, due to its ability to modulate inflammation and promote healing. More recently, cells isolated from the amniotic membrane are being considered as a possible resource for tissue regeneration, including in the context liver disease. Two cell types can be easily isolated from human amnion: epithelial cells (hAEC) and mesenchymal stromal cells (hAMSC). However only the first cell population has been demonstrated to be a possible source of proficient hepatic cells. This review will summarize current knowledge on the differentiation of hAEC into liver cells and their potential therapeutic application.
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http://dx.doi.org/10.1016/j.placenta.2017.03.020DOI Listing
November 2017

Hyperplasia hypertrophy in tissue regeneration after extensive liver resection.

World J Gastroenterol 2017 Mar;23(10):1764-1770

Fabio Marongiu, Michela Marongiu, Antonella Contini, Monica Serra, Erika Cadoni, Riccardo Murgia, Ezio Laconi, Experimental Medicine Unit, Department of Biomedical Sciences, University of Cagliari, 09124 Cagliari, Italy.

Aim: To address to what extent hypertrophy and hyperplasia contribute to liver mass restoration after major tissue loss.

Methods: The ability of the liver to regenerate is remarkable on both clinical and biological grounds. Basic mechanisms underlying this process have been intensively investigated. However, it is still debated to what extent hypertrophy and hyperplasia contribute to liver mass restoration after major tissue loss. We addressed this issue using a genetically tagged system. We were able to follow the fate of single transplanted hepatocytes during the regenerative response elicited by 2/3 partial surgical hepatectomy (PH) in rats. Clusters of transplanted cells were 3D reconstructed and their size distribution was evaluated over time after PH.

Results: Liver size and liver DNA content were largely recovered 10 d post-PH, as expected (., total DNA/liver/100 g b.w. was 6.37 ± 0.21 before PH and returned to 6.10 ± 0.36 10 d after PH). Data indicated that about 2/3 of the original residual hepatocytes entered S-phase in response to PH. Analysis of cluster size distribution at 24, 48, 96 h and 10 d after PH revealed that about half of the remnant hepatocytes completed at least 2 cell cycles. Average size of hepatocytes increased at 24 h (248.50 μm ± 7.82 μm, = 0.0015), but returned to control values throughout the regenerative process (up to 10 d post-PH, 197.9 μm ± 6.44 μm, = 0.11). A sizeable fraction of the remnant hepatocyte population does not participate actively in tissue mass restoration.

Conclusion: Hyperplasia stands as the major mechanism contributing to liver mass restoration after PH, with hypertrophy playing a transient role in the process.
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http://dx.doi.org/10.3748/wjg.v23.i10.1764DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5352916PMC
March 2017

Aging promotes neoplastic disease through effects on the tissue microenvironment.

Aging (Albany NY) 2016 12;8(12):3390-3399

Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari, 09124, Cagliari, Italy.

A better understanding of the complex relationship between aging and cancer will provide important tools for the prevention and treatment of neoplasia. In these studies, the hypothesis was tested that aging may fuel carcinogenesis via alterations imposed in the tissue microenvironment. Preneoplastic hepatocytes isolated from liver nodules were orthotopically injected into either young or old syngeneic rats and their fate was followed over time using the dipeptidyl-peptidase type IV (DPPIV) system to track donor-derived-cells. At 3 months post-Tx, the mean size of donor-derived clusters was 11±3 cells in young vs. 42±8 in old recipients. At 8 months post-Tx, no visible lesion were detected in any of 21 young recipients, while 17/18 animals transplanted at old age displayed hepatic nodules, including 7 large tumors. All tumors expressed the DPPIV marker enzyme, indicating that they originated from transplanted cells. Expression of senescence-associated β-galactosidase was common in liver of 18-month old animals, while it was a rare finding in young controls. Finally, both mRNA and IL6 protein were found to be increased in the liver of aged rats compared to young controls. These results are interpreted to indicate that the microenvironment of the aged liver promotes the growth of pre-neoplastic hepatocytes.
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http://dx.doi.org/10.18632/aging.101128DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5270675PMC
December 2016

The Use of Induced Pluripotent Stem Cells for the Study and Treatment of Liver Diseases.

Curr Protoc Toxicol 2016 Feb 1;67:14.13.1-14.13.27. Epub 2016 Feb 1.

McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania.

Liver disease is a major global health concern. Liver cirrhosis is one of the leading causes of death in the world and currently the only therapeutic option for end-stage liver disease (e.g., acute liver failure, cirrhosis, chronic hepatitis, cholestatic diseases, metabolic diseases, and malignant neoplasms) is orthotropic liver transplantation. Transplantation of hepatocytes has been proposed and used as an alternative to whole organ transplant to stabilize and prolong the lives of patients in some clinical cases. Although these experimental therapies have demonstrated promising and beneficial results, their routine use remains a challenge due to the shortage of donor livers available for cell isolation, variable quality of those tissues, the potential need for lifelong immunosuppression in the transplant recipient, and high costs. Therefore, new therapeutic strategies and more reliable clinical treatments are urgently needed. Recent and continuous technological advances in the development of stem cells suggest they may be beneficial in this respect. In this review, we summarize the history of stem cell and induced pluripotent stem cell (iPSC) technology in the context of hepatic differentiation and discuss the potential applications the technology may offer for human liver disease modeling and treatment. This includes developing safer drugs and cell-based therapies to improve the outcomes of patients with currently incurable health illnesses. We also review promising advances in other disease areas to highlight how the stem cell technology could be applied to liver diseases in the future. © 2016 by John Wiley & Sons, Inc.
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http://dx.doi.org/10.1002/0471140856.tx1413s67DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4795152PMC
February 2016

Gas-phase fragmentation of the N-oxide and N-hydroxylated derivatives of retrorsine using liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

Rapid Commun Mass Spectrom 2015 Oct;29(19):1733-48

Chemistry Department, Memorial University of Newfoundland, Saint John's, Canada.

Rationale: We report the electrospray ionization mass spectrometry and low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS) analysis of a pyrrolizidine alkaloid extract containing both retrorsine [C18H25NO6] and its N-oxide [C18H25NO7] and N-hydroxyl [C18H26NO7] derivatives measured with a QqTOFMS hybrid instrument.

Methods: A solution of the pyrrolizidine alkaloid extract containing retrorsine and its N-oxide and N-hydroxyl derivatives was directly infused into an electrospray ionization-quadrupole-time-of-flight (ESI-QTOF) mass spectrometer and product ion scans of the protonated molecules of each species were acquired. Labile protons of each compound were deuterated and computational energy calculations of the proposed structures of the product ions were used to determine the fragmentation pathways of retrorsine and its N-oxide and N-hydroxyl derivatives.

Results: ESI-MS of the pyrrolizidine alkaloid extract containing retrorsine and its N-oxide and N-hydroxyl derivatives afforded the protonated retrorsine [M1 + H](+) at m/z 352.1760 and the protonated retrorsine N-oxide [M2 + H](+) at m/z 368.1631 in addition to the formation of the unexpected protonated N-hydroxyl radical [M3 + H](+•) at m/z 369.1686. CID-MS/MS of this series of protonated molecules allowed the evaluation of their gas-phase fragmentations and the establishment of their fragmentation pathways. It was also found that several product ions could be assigned to different structures. Deuterium exchange and computational energy calculations allowed us to determine the most probable structures for the characterized product ions.

Conclusions: To our knowledge, the identification of the protonated retrorsine N-hydroxyl radical [M3 + H](+•) is reported for the first time. In addition, the MS/MS results can be used for the identification of retrorsine and its N-oxide and N-hydroxyl derivatives in different complex biological matrices.
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http://dx.doi.org/10.1002/rcm.7276DOI Listing
October 2015

Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

Carcinogenesis 2015 Jun;36 Suppl 1:S254-96

Superfund Research Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27560, USA.

Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology.
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http://dx.doi.org/10.1093/carcin/bgv039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480130PMC
June 2015

The effect of environmental chemicals on the tumor microenvironment.

Carcinogenesis 2015 Jun;36 Suppl 1:S160-83

Center for Experimental Molecular Medicine (CEMM), Academic Medical Center (AMC), Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.

Potentially carcinogenic compounds may cause cancer through direct DNA damage or through indirect cellular or physiological effects. To study possible carcinogens, the fields of endocrinology, genetics, epigenetics, medicine, environmental health, toxicology, pharmacology and oncology must be considered. Disruptive chemicals may also contribute to multiple stages of tumor development through effects on the tumor microenvironment. In turn, the tumor microenvironment consists of a complex interaction among blood vessels that feed the tumor, the extracellular matrix that provides structural and biochemical support, signaling molecules that send messages and soluble factors such as cytokines. The tumor microenvironment also consists of many host cellular effectors including multipotent stromal cells/mesenchymal stem cells, fibroblasts, endothelial cell precursors, antigen-presenting cells, lymphocytes and innate immune cells. Carcinogens can influence the tumor microenvironment through effects on epithelial cells, the most common origin of cancer, as well as on stromal cells, extracellular matrix components and immune cells. Here, we review how environmental exposures can perturb the tumor microenvironment. We suggest a role for disrupting chemicals such as nickel chloride, Bisphenol A, butyltins, methylmercury and paraquat as well as more traditional carcinogens, such as radiation, and pharmaceuticals, such as diabetes medications, in the disruption of the tumor microenvironment. Further studies interrogating the role of chemicals and their mixtures in dose-dependent effects on the tumor microenvironment could have important general mechanistic implications for the etiology and prevention of tumorigenesis.
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http://dx.doi.org/10.1093/carcin/bgv035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4565612PMC
June 2015

Rat-derived amniotic epithelial cells differentiate into mature hepatocytes in vivo with no evidence of cell fusion.

Stem Cells Dev 2015 Jun 6;24(12):1429-35. Epub 2015 Mar 6.

1Experimental Medicine Unit, Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy.

Amniotic epithelial cells (AEC) derived from human placenta represent a useful and noncontroversial source for liver-based regenerative medicine. Previous studies suggested that human- and rat-derived AEC differentiate into hepatocyte-like cells upon transplantation. In the retrorsine (RS) model of liver repopulation, clusters of donor-derived cells engrafted in the recipient liver and, importantly, showed characteristics of mature hepatocytes. The aim of the current study was to investigate the possible involvement of cell fusion in the emergence of hepatocyte clusters displaying a donor-specific phenotype. To this end, 4-week-old GFP(+)/DPP-IV(-) rats were treated with RS and then transplanted with undifferentiated AEC isolated from the placenta of DPP-IV(+) pregnant rats at 16-19 days of gestational age. Results indicated that clusters of donor-derived cells were dipeptidyl peptidase type IV (DPP-IV) positive, but did not express the green fluorescent protein (GFP), suggesting that rat amniotic epithelial cells (rAEC) did not fuse within the host parenchyma, as no colocalization of the two tags was observed. Moreover, rAEC-derived clusters expressed markers of mature hepatocytes (eg, albumin, cytochrome P450), but were negative for the expression of biliary/progenitor markers (eg, epithelial cell adhesion molecule [EpCAM]) and did not express the marker of preneoplastic hepatic nodules glutathione S-transferase P (GST-P). These results extend our previous findings on the potential of AEC to differentiate into mature hepatocytes and suggest that this process can occur in the absence of cell fusion with host-derived cells. These studies support the hypothesis that amnion-derived epithelial cells can be an effective cell source for the correction of liver disease.
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http://dx.doi.org/10.1089/scd.2014.0532DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4486142PMC
June 2015

Cell-autonomous decrease in proliferative competitiveness of the aged hepatocyte.

J Hepatol 2015 Jun 21;62(6):1341-8. Epub 2015 Jan 21.

University of Cagliari, Department of Biomedical Sciences, Unit of Experimental Medicine, Cagliari, Italy. Electronic address:

Background & Aims: The regenerative potential of the liver declines with age, this might be dependent on a decrease in the intensity of the stimulus and/or an increased refractoriness of the target. In the present study, we compared the in vivo growth capacity of young and old hepatocytes transplanted into the same host.

Methods: We utilized the retrorsine (RS)-based model for liver repopulation, which provides a specific and effective stimulus for transplanted hepatocytes. Rats of the dipeptidyl-peptidase type IV (DPP-IV)-deficient strain were given RS and were injected with a mix of hepatocytes isolated from either a 2-month old or an 18-month old donor. To follow the fate of transplanted cells, they were each identified through a specific tag: young hepatocytes expressed the green fluorescent protein (GFP(+)), while those from old donors were DPP-IV-positive.

Results: At 1 month post-transplantation, DPP-IV-positive clusters (derived from old donor) were consistently smaller than those GFP(+) (young donor); the cross sectional area of clusters was decreased by 50%, while the mean volume was reduced to 1/3. Furthermore, when 2/3 partial hepatectomy (PH) was performed, the S-phase response of old hepatocyte-derived clusters was only 30-40% compared to that observed in cluster originating from young hepatocytes. No markers of cell senescence were expressed in clusters of transplanted hepatocytes.

Conclusions: This is the first direct evidence in vivo that hepatocytes in the aged liver express a cell-autonomous decline in their replicative capacity and in their regenerative response to PH compared to those from a young animal.
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http://dx.doi.org/10.1016/j.jhep.2015.01.015DOI Listing
June 2015

The history and use of human hepatocytes for the treatment of liver diseases: the first 100 patients.

Curr Protoc Toxicol 2014 Nov 6;62:14.12.1-23. Epub 2014 Nov 6.

Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania.

Orthotopic liver transplantation remains the only curative treatment for many end-stage liver diseases, yet the number of patients receiving liver transplants remains limited by the number of organs available for transplant. There is a need for alternative therapies for liver diseases. The transplantation of isolated hepatocytes (liver cells) has been used as an experimental therapy for liver disease in a limited number of cases. Recently, the 100th case of hepatocyte transplantation was reported. This review discusses the history of the hepatocyte transplant field, the major discoveries that supported and enabled the first hepatocyte transplants, and reviews the cases and outcomes of the first 100 clinical transplants. Some of the problems that limit the application or efficacy of hepatocyte transplantation are discussed, as are possible solutions to these problems. In conclusion, hepatocyte transplants have proven effective particularly in cases of metabolic liver disease where reversal or amelioration of the characteristic symptoms of the disease is easily quantified. However, no patients have been completely corrected of a metabolic liver disease for a significant amount of time by hepatocyte transplantation alone. It is likely that future developments in new sources of cells for transplantation will be required before this cellular therapy can be fully implemented and available for large numbers of patients.
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http://dx.doi.org/10.1002/0471140856.tx1412s62DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4343212PMC
November 2014

Hepatocyte senescence induced by radiation and partial hepatectomy in rat liver.

Int J Radiat Biol 2014 Oct 25;90(10):876-83. Epub 2014 Jun 25.

Department of Biomedical Sciences, University of Cagliari , Italy.

Purpose: Exposure to radiation primes the liver for extensive replacement of the resident parenchymal cells by transplanted hepatocytes. The mechanisms underlying this repopulation remain to be clarified. In these studies, we examined the possible occurrence of cell senescence in vivo following radiation-associated preconditioning of the host liver.

Materials And Methods: Fischer 344 rats underwent external-beam, computed-tomography-based partial liver irradiation. A single dose of 25 Gy was delivered to the right liver lobes (40% of liver mass). An additional group of animals received a 1/3 partial hepatectomy (removal of the left anterior lobe) four days after irradiation. Non-irradiated groups served as controls. All rats were sacrificed four weeks after the initial treatment.

Results: The irradiated livers displayed several markers of cell senescence, including expression of senescence-associated-β-galactosidase (SA-β-gal), increase in cell size, and up-regulation of cyclin-dependent kinase inhibitors (CDK-I) p16 and p21. Furthermore, quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) analysis revealed activation of the senescence-associated secretory phenotype (SASP), including the cytokines interleukin 6 (IL6) and 1α (IL1α). The senescence-related changes were more prominent in rats undergoing partial hepatectomy (PH) following irradiation (IR).

Conclusions: We conclude that priming with radiation for liver repopulation results in the induction of cell senescence and the up-regulation of a senescence-associated secretory phenotype. The latter can contribute to the extensive growth of transplanted cells in this system.
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http://dx.doi.org/10.3109/09553002.2014.922714DOI Listing
October 2014

Cell turnover in the repopulated rat liver: distinct lineages for hepatocytes and the biliary epithelium.

Cell Tissue Res 2014 May 1;356(2):333-40. Epub 2014 Apr 1.

Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari School of Medicine, Via Porcell 4, 3rd Floor, Cagliari, 09124, Italy.

The dynamics of cell renewal in the normal adult liver remains an unresolved issue. We investigate the possible contribution of a common biliary precursor cell pool to hepatocyte turnover in the chimeric long-term repopulated rat liver. The retrorsine (RS)-based model of massive liver repopulation was used. Animals not expressing the CD26 marker (CD26(-)) were injected with RS, followed by transplantation of 2 million syngeneic hepatocytes isolated from a normal CD26-expressing donor. Extensive (80-90%) replacement of resident parenchymal cells was observed at 1 year post-transplantation and persisted at 2 years, as expected. A panel of specific markers, including cytokeratin 7, OV6, EpCAM, claudin 7 and α-fetoprotein, was employed to locate the in situ putative progenitor and/or biliary epithelial cells in the stably repopulated liver. No overlap was observed between any of these markers and the CD26 tag identifying transplanted cells. Exposure to RS was not inhibitory to the putative progenitor and/or biliary epithelial cells, nor did we observe any evidence of cell fusion between these cells and the transplanted cell population. Given the long-term (>2 years) stability of the donor cell phenotype in this model of liver repopulation, the present findings suggest that hepatocyte turnover in the repopulated liver is fuelled by a cell lineage distinct from that of the biliary epithelium and relies largely on the differentiated parenchymal cell population. These results support the solid biological foundation of liver repopulation strategies based on the transplantation of isolated hepatocytes.
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http://dx.doi.org/10.1007/s00441-014-1800-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4015059PMC
May 2014

Clearance of senescent hepatocytes in a neoplastic-prone microenvironment delays the emergence of hepatocellular carcinoma.

Aging (Albany NY) 2014 Jan;6(1):26-34

Department of Biomedical Sciences, Unit of Experimental Medicine, University of Cagliari, 09124 Cagliari, Italy.

Increasing evidence indicates that carcinogenesis is dependent on the tissue context in which it occurs, implying that the latter can be a target for preventive or therapeutic strategies. We tested the possibility that re-normalizing a senescent, neoplastic-prone tissue microenvironment would exert a modulatory effect on the emergence of neoplastic disease. Rats were exposed to a protocol for the induction of hepatocellular carcinoma (HCC). Using an orthotopic and syngeneic system for cell transplantation, one group of animal was then delivered 8 million normal hepatocytes, via the portal circulation. Hepatocytes transplantation resulted in a prominent decrease in the incidence of both pre-neoplastic and neoplastic lesions. At the end of 1 year 50% of control animals presented with HCC, while no HCC were observed in the transplanted group. Extensive hepatocyte senescence was induced by the carcinogenic protocol in the host liver; however, senescent cells were largely cleared following infusion of normal hepatocytes. Furthermore, levels of Il-6 increased in rats exposed to the carcinogenic protocol, while they returned to near control values in the group receiving hepatocyte transplantation. These results support the concept that strategies aimed at normalizing a neoplastic-prone tissue landscape can modulate progression of neoplastic disease.
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http://dx.doi.org/10.18632/aging.100631DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3927807PMC
January 2014
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