Abstract Despite routine liver transplantation and supporting medical therapies, thousands of patients currently wait for an organ and there is an unmet need for more refined and widely available ...regenerative strategies to treat liver diseases. Cell transplants attempt to maximize the potential for repair and/or regeneration in liver and other organs. Over 40 years of laboratory pre-clinical research and 25 years of clinical procedures have shown that certain liver diseases can be treated by the infusion of isolated cells (hepatocyte transplant). However, like organ transplants, hepatocyte transplant suffers from a paucity of tissues useful for cell production. Alternative sources have been investigated, yet with limited success. The tumorigenic potential of pluripotent stem cells together with their primitive level of hepatic differentiation, have limited the use of stem cell populations. Stem cell sources from human placenta, and the amnion tissue in particular are receiving renewed interest in the field of regenerative medicine. Unlike pluripotent stem cells, human amnion epithelial (AE) cells are easily available without ethical or religious concerns; they do not express telomerase and are not immortal or tumorigenic when transplanted. In addition, AE cells have been reported to express genes normally expressed in mature liver, when transplanted into the liver. Moreover, because of the possibility of an immune-privileged status related to their expression of HLA-G, it might be possible to transplant human AE cells without immunosuppression of the recipient.
Three decades of hepatocyte transplantation have confirmed such a cell-based approach as an adjunct or alternative treatment to solid organ transplantation. Donor cell survival and engraftment were ...indirectly measured by hepatospecific secretive or released metabolites, such as ammonia metabolism in urea cycle defects. In cases of sepsis or viral infection, ammonia levels can significantly and abruptly increase in these recipients, erroneously implying rejection. Pro-inflammatory cytokines associated with viral or bacterial infections are known to affect many liver functions, including drug-metabolizing enzymes and hepatic transport activities. We examined the influence of pro-inflammatory cytokines in primary human hepatocytes, isolated from both normal donors or patients with metabolic liver diseases. Different measures of hepatocyte functions, including ammonia metabolism and phase 1-3 metabolism, were performed. All the hepatic functions were profoundly and significantly suppressed after exposure to concentrations of from 0.1 to 10 ng/mL of different inflammatory cytokines, alone and in combination. Our data indicate that, like phase I metabolism, suppression of phase II/III and ammonia metabolism occurs in hepatocytes exposed to pro-inflammatory cytokines in the absence of cell death. Such inflammatory events do not necessarily indicate a rejection response or loss of the cell graft, and these systemic inflammatory signals should be carefully considered when the immunosuppressant regiment is reduced or relieved in a hepatocyte transplantation recipient in response to such alleged rejection.
The beneficial health properties of the Mediter-ranean diet are well recognized. The principle source of fat in Mediterranean diet is extra-virgin olive oil (EVOO). Oleocanthal (OC) is a naturally ...occurring minor phenolic compound isolated from EVOO, which has shown a potent anti-inflammatory activity, by means of its ability to inhibit the cyclooxygenase (COX) enzymes COX-1 and COX-2. A large body of evidence indicates that phenols exhibit anticancer activities. The aim of the present study was to evaluate the potential anticancer effects of OC in hepatocellular carcinoma (HCC) and colorectal carcinoma (CRC) models. A panel of human HCC (HepG2, Huh7, Hep3B and PLC/PRF/5) and CRC (HT29, SW480) cell lines was used. Cells were treated with OC, and cell viability and apoptosis were evaluated. Compared with classical commercially available COX inhibitors (ibuprofen, indomethacin, nimesulide), OC was more effective in inducing cell growth inhibition in HCC and CRC cells. Moreover, OC inhibited colony formation and induced apoptosis, as confirmed by PARP cleavage, activation of caspases 3/7 and chromatin condensation. OC treatment in a dose dependent-manner induced expression of γH2AX, a marker of DNA damage, increased intracellular ROS production and caused mitochondrial depolarization. Moreover, the effects of OC were suppressed by the ROS scavenger N-acetyl-L-cysteine. Finally, OC was not toxic in primary normal human hepatocytes. In conclusion, OC treatment was found to exert a potent anticancer activity against HCC and CRC cells. Taken together, our findings provide preclinical support of the chemotherapeutic potential of EVOO against cancer.
Differentiation of stem cells to hepatocyte-like cells (HLCs) holds great promise for basic research, drug and toxicological investigations, and clinical applications. There are currently no ...protocols for the production of HLCs from stem cells, such as embryonic stem cells or induced pluripotent stem cells, that produce fully mature hepatocytes with a wide range of mature hepatic functions. This report describes a standard method to assess the maturation of stem cell-derived HLCs with a moderately high-throughput format, by analysing liver gene expression by quantitative RT-qPCR. This method also provides a robust data set of the expression of 62 genes expressed in normal liver, generated from 17 fetal and 25 mature human livers, so that investigators can quickly and easily compare the expression of these genes in their stem cell-derived HLCs with the values obtained in authentic fetal and mature human liver. The simple methods described in this study will provide a quick and accurate assessment of the efficacy of a differentiation protocol and will help guide the optimization of differentiation conditions.
Human amniotic cells (hAC) possess multiple unique immunomodulatory properties. They are believed to be a very appealing and safe material for clinical applications. Primary hAC have been proposed as ...an efficient source of immunomodulatory factors that could be used as alternative or supporting to classical drug immunosuppression. The aim of this study was to evaluate hAC immunomodulatory properties post-activation by inflammatory cytokines as Interleukin 1β and Interferon γ.
hAC were isolated and characterized by the expression of pluripotency marker SSEA4, epithelial marker CK7, HLA-G antigen, mRNA for PTGS2, NOS2 and HLA-G gene, and secretion of soluble mediators as HLA-G and PGE2 in the culture medium in presence or absence of INF-γ and IL-1β.
Heterogeneity of the cultured hAC was proved, with 50 ± 8% of cells positive for epithelial marker (CK7), and 73 ± 3% expressing SSEA4 pluripotency marker. Priming effect by in vitro exposure to INF-γ and IL-1β resulted in a significant increase in expression of PTGS2, NOS2 and HLA-G gene, with a peak between 32 and 64 h. The highest PGE2 concentration was measured in the culture medium at 48 h. At 96 h, a significant difference in the percentage of SSEA4+ hAC between activated and non-activated cells, as well as the highest expression of HLA-G - especially in SSEA4+ cells, and highly elevated concentration of soluble HLA-G (sHLA-G) in the medium of activated cells, were found.
The prolonged exposure of primary human amnion-derived cells to inflammatory cytokines INF-γ and IL-1β may result in enhanced expression and secretion of immunomodulatory molecules important in allogenic therapies.
Organ and tissue shortage are known as a crucially important public health problem as unfortunately a small percentage of patients receive transplants. In the context of emerging regenerative ...medicine, researchers are trying to regenerate and replace different organs and tissues such as the liver, heart, skin, and kidney. Liver tissue engineering (TE) enables us to reproduce and restore liver functions, fully or partially, which could be used in the treatment of acute or chronic liver disorders and/or generate an appropriate functional organ which can be transplanted or employed as an extracorporeal device. In this regard, a variety of techniques (e.g., fabrication technologies, cell-based technologies, microfluidic systems and, extracorporeal liver devices) could be applied in tissue engineering in liver regenerative medicine. Common TE techniques are based on allocating stem cell-derived hepatocyte-like cells or primary hepatocytes within a three-dimensional structure which leads to the improvement of their survival rate and functional phenotype. Taken together, new findings indicated that developing liver tissue engineering-based techniques could pave the way for better treatment of liver-related disorders. Herein, we summarized novel technologies used in liver regenerative medicine and their future applications in clinical settings.
Toll-like receptors (TLRs) represent one of the bridges that regulate the cross-talk between the innate and adaptive immune systems. TLRs interact with molecules shared and preserved by the pathogens ...of origin but also with endogenous molecules (damage/danger-associated molecular patterns (DAMPs)) that derive from injured tissues. This is probably why TLRs have been found to be expressed on several kinds of stem/progenitor cells (SCs). In these cells, the role of TLRs in the regulation of the basal motility, proliferation, differentiation processes, self-renewal, and immunomodulation has been demonstrated. In this review, we analyze the many different functions that the TLRs assume in SCs, pointing out that they can have different effects, depending on the background and on the kind of ligands that they recognize. Moreover, we discuss the TLR involvement in the response of SC to specific tissue damage and in the reparative processes, as well as how the identification of molecules mediating the differential function of TLR signaling could be decisive for the development of new therapeutic strategies. Considering the available studies on TLRs in SCs, here we address the importance of TLRs in sensing an injury by stem/progenitor cells and in determining their behavior and reparative activity, which is dependent on the conditions. Therefore, it could be conceivable that SCs employed in therapy could be potentially exposed to TLR ligands, which might modulate their therapeutic potential in vivo. In this context, to modulate SC proliferation, survival, migration, and differentiation in the pathological environment, we need to better understand the mechanisms of action of TLRs on SCs and learn how to control these receptors and their downstream pathways in a precise way. In this manner, in the future, cell therapy could be improved and made safer.
Introduction Increased free-radical production, decreased antioxidant capacity, and excessive inflammation are well-known features in the pathogenesis of inflammatory bowel disease. Melatonin is a ...powerful antioxidant and a scavenger of hydroxyl radicals. Melatonin has also been shown to have anti-inflammatory activities in tissues. Our study objective is to investigate the effects of melatonin on tissue inflammatory activities using an ulcerative colitis (UC) model induced by acetic acid (AA) in rats. Methods Wistar rats (n = 32) were divided into four groups. AA-induced colitis was performed in two of the groups, while the other two groups were injected with saline intrarectally. One of the AA-induced colitis groups and one of the control groups were administered 100 mg/kg/day melatonin intraperitoneally, and the pair groups were given saline. After 4 days, colonic changes were evaluated biochemically by measuring proinflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, myeloperoxidase (MPO), malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) levels in tissue homogenates and by histopathological examination. Results AA caused colonic mucosal injury, whereas melatonin suppressed these changes in the AA-induced colitis group (P < 0.001). AA administration resulted in increased TNF-α, IL-1β, IL-6, MPO, and MDA levels, and decreased GSH and SOD levels, whereas melatonin administration reversed these effects (all P < 0.001). Conclusions The present study proposes that melatonin has a dual action as an effective anti-inflammatory and an antioxidant, and may be a hopeful therapeutic agent for UC.
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