Mónica Luján López

Platelet increases survival in a model of 90% hepatectomy in rats.

Ninety per cent hepatectomy in rodents is a model for acute liver failure. It has been reported that platelets have a strong effect enhancing liver regeneration, because of the production of several growth factors such as serotonin. The aim of this study was to investigate the role of microencapsulated platelets on 90% hepatectomy in rats.

Recommendations on Reintroduction of Agalsidase Beta for Patients with Fabry Disease in Europe, Following a Period of Shortage

The interruption of the manufacturing process of agalsidase beta has led to a worldwide shortage of this drug. In the EU, nearly all patients initially reduced their agalsidase beta dose, and many of these switched to agalsidase alfa (Replagal Shire HGT). The clinical consequences of this period of drug shortage need to be further evaluated. A gradual increase of agalsidase beta supply is now expected. This implies that patients could resume or even commence agalsidase beta treatment. Guidance for prioritization of patients is needed to support equitable distribution of agalsidase beta to EU member states. To achieve this, in absence of level I clinical evidence, a draft consensus proposal was initiated and distributed. No full consensus was achieved, as there is disagreement regarding the indications for switching patients from agalsidase alfa to agalsidase beta. Some physicians support the concept that the 1.0 mg/kg EOW dose of agalsidase beta is more effective than agalsidase alfa at 0.2 mg/kg EOW, while others believe that at recommended dose, the preparations are equivalent. In light of these difficulties and the uncertainties with respect to supply of agalsidase beta, recommendations were agreed upon by a subgroup of physicians. These current recommendations focus on prioritization of criteria indicative of disease progression.

Bone Marrow-Derived Mononuclear Cells Differentiate into Hepatocyte-Like Cells within Few Hrs without Fusion

Background: Cell therapy using Bone Marrow Mononuclear Cells (BMMC) has been shown as a potential treatment for liver diseases. BMMC can act by fusion, differentiation into hepatocyte-like cells and/or secretion of paracrine factors. Here, we used encapsulated BMMC in a model of Carbon Tetrachloride (CCl4)-induced acute liver injury to study in vivo and in vitro differentiation of BMMC. Methods: Both in vitro and in vivo studies were conducted in Wistar rats submitted to CCl4-induced acute liver injury. BMMC were isolated from Wistar rats and encapsulated in sodium alginate microcapsules. For in vivo experiments, animals received encapsulated BMMC 24 hrs after CCl4 administration and capsules were collected within 6, 24 and 48 hrs (tCCl4 group). For in vitro experiments, isolated hepatocytes from animals with CCl4-induced liver injury were co-cultured with encapsulated BMMC for 6 h (cCCl4 group). Control groups were not submitted to CCl4 administration. The content of intracellular lipid droplets in hepatocytes was used to evaluate liver injury. BMMC differentiation was assessed by RT-PCR for hepatic genes and ability to produce and secrete urea. Results: Liver damage was confirmed in CCl4 treated animals by the presence of intracellular lipid droplets in hepatocytes and the characteristic nutmeg aspect of the liver. Retrieved encapsulated BMMC from tCCl4 group expressed hepatocyte markers, such as Cytokeratin 18 and Albumin 48 hrs after treatment. On the other hand, BMMC from cCCl4 group showed Albumin expression 6 hrs after co-culture. Urea production was increased in BMMC from cCCl4 group but not in cControl. BMMC from tControl or cControl groups did not express hepatocyte markers at any time point. Conclusions: In this study we show that BMMC differentiate into hepatocyte-like cells in a short period of time both in vivo and in vitro. This differentiation is triggered by paracrine factors present only in injured liver.

Encapsulated whole bone marrow cells improve survival in wistar rats after 90% partial hepatectomy

Background and Aims. The use of bone marrow cells has been suggested as an alternative treatment for acute liver failure. In this study, we investigate the effect of encapsulated whole bone marrow cells in a liver failure model. Methods. Encapsulated cells or empty capsules were implanted in rats submitted to 90% partial hepatectomy. The survival rate was assessed. Another group was euthanized at 6, 12, 24, 48, and 72 hours after hepatectomy to study expression of cytokines and growth factors. Results. Whole bone marrow group showed a higher than 10 days survival rate compared to empty capsules group. Gene expression related to early phase of liver regeneration at 6 hours after hepatectomy was decreased in encapsulated cells group, whereas genes related to regeneration were increased at 12, 24, and 48 hours. Whole bone marrow group showed lower regeneration rate at 72 hours and higher expression and activity of caspase 3. In contrast, lysosomal-β-glucuronidase activity was elevated in empty capsules group. Conclusions. The results show that encapsulated whole bone marrow cells reduce the expression of genes involved in liver regeneration and increase those responsible for ending hepatocyte division. In addition, these cells favor apoptotic cell death and decrease necrosis, thus increasing survival.

Encapsulated platelets modulate kupffer cell activation and reduce oxidative stress in a model of acute liver failure.

Acute liver failure (ALF) is characterized by massive hepatocyte cell death. Kupffer cells (KC) are the first cells to be activated after liver injury. They secrete cytokines and produce reactive oxygen species, leading to apoptosis of hepatocytes. In a previous study, we showed that encapsulated platelets (PLTs) increase survival in a model of ALF. Here, we investigate how PLTs exert their beneficial effect. Wistar rats submitted to 90% hepatectomy were treated with PLTs encapsulated in sodium alginate or empty capsules. Animals were euthanized at 6, 12, 24, 48, and 72 hours after hepatectomy, and livers were collected to assess oxidative stress, caspase activity, and gene expression related to oxidative stress or liver function. The number of KCs in the remnant liver was evaluated. Interaction of encapsulated PLTs and KCs was investigated using a coculture system. PLTs increase superoxide dismutase and catalase activity and reduce lipid peroxidation. In addition, caspase 3 activity was reduced in animals receiving encapsulated PLTs at 48 and 72 hours. Gene expression of endothelial nitric oxide synthase and nuclear factor kappa B were elevated in the PLT group at each time point analyzed. Gene expression of albumin and factor V also increased in the PLT group. The number of KCs in the PLT group returned to normal levels at 12 hours but remained elevated in the control group until 72 hours. Finally, PLTs modulate interleukin (IL) 6 and IL10 expression in KCs after 24 hours of coculture. In conclusion, these results indicate that PLTs interact with KCs in this model and exert their beneficial effect through reduction of oxidative stress that results in healthier hepatocytes and decreased apoptosis. Liver Transplantation 22 1562–1572 2016 AASLD.

Injured hepatocyte-released microvesicles induce bone marrow-derived mononuclear cells differentiation

The ability of bone marrow-derived mononuclear cells (BMMCs) to differentiate into hepatocyte-like cells under different conditions has been demonstrated previously. In the present study, we investigated the effect of CCl4-injured hepatocytes on the differentiation of the non-adherent (NAD) fraction of BMMCs. Differentiation (cell fate) was analyzed after 2, 6 and 24h of co-culture by gene and protein expression and by urea production. We also evaluated the presence of microvesicles (MVs) in the supernatant of differentiated cells, their content and the ability of these cells to absorb them. Hepatocyte-like characteristics were observed in the NAD cells after 24h of co-culture with injured hepatocytes. Cells that were co-cultured with healthy hepatocytes did not present signs of differentiation at any analyzed time point. Analysis of the supernatant from differentiated cells revealed the presence of MVs carrying hepatocyte-specific mRNAs, including Albumin, Coagulation factor V, Alpha-fetoprotein, and Cytokeratin 18. The incorporation of injured hepatocyte-derived MVs by NAD cells was shown at 24h, suggesting a possible role for MVs in the induction of cell plasticity.

Paracrine Effects of Bone Marrow Mononuclear Cells in Survival and Cytokine Expression after 90% Partial Hepatectomy

Acute liver failure is a complex and fatal disease. Cell-based therapies are a promising alternative therapeutic approach for liver failure due to relatively simple technique and lower cost. The use of semipermeable microcapsules has become an interesting tool for evaluating paracrine effects in vivo. In this study, we aimed to assess the paracrine effects of bone marrow mononuclear cells (BMMC) encapsulated in sodium alginate to treat acute liver failure in an animal model of 90% partial hepatectomy (90% PH). Encapsulated BMMC were able to increase 10-day survival without enhancing liver regeneration markers. Gene expression of Il-6 and Il-10 in the remnant liver was markedly reduced at 6 h after 90% PH in animals receiving encapsulated BMMC compared to controls. This difference, however, was neither reflected by changes in the number of CD68+ cells nor by serum levels of IL6. On the other hand, treated animals presented increased caspase activity and gene expression in the liver. Taken together, these results suggest that BMMC regulate immune response and promote apoptosis in the liver after 90% PH by paracrine factors. These changes ultimately may be related to the higher survival observed in treated animals, suggesting that BMMC may be a promising alternative to treat acute liver failure.

ERK 1/2 activation does not contribute to increased survival mediated by bone marrow cells after 90% partial hepatectomy in wistar rats

We investigated the influence of bone marrow cells upon activation of ERK ½ in an animal model of 90% PH. Phosphorylated ERK 1/2 was evaluated by western blot. No differences were found between the groups. Thus, increased survival does not appear to be mediated by ERK 1/2 activation. Keywords: MAP Kinase Signaling System; stem cells; acute liver failure

The challenges of organizing an international course in Latin America

The Latin American School of Human and Medical Genetics (ELAG) is the main course of its kind in the genetics field in Latin America. Here we describe the main challenges regarding the organization of such event, including how we obtain funding and how we proceed with student selection. Thus, we aim to share our experience with other groups that intend to follow this format to create similar events in other areas in this region of the world.