Previous investigations have provided evidence that the Nterminal peptide of annexin 1 (peptide Ac2-26) has the capacity of reproducing the anti-inflammatory actions of the full-length protein in many systems. In the current study, we report the effectiveness of the peptide Ac2-26 as an antiallergic tool in a model of rat pleurisy and provide indication for some of the mechanisms involved. In rats inflamed by injection of ovalbumin into the pleural cavity 14 days postsensitization, peptide Ac2-26 (50 -200 g/cavity) inhibited mast cell degranulation, plasma protein leakage, and the accumulation of both neutrophils and eosinophils. Treatment with either peptide Ac2-26 (200 g/cavity) or dexamethasone (1 mg/kg i.p.) inhibited ovalbumin-induced eotaxin release in the pleural effluents. In vitro, peptide Ac2-26 inhibited ovalbumin-evoked histamine release from subcutaneous tissue fragments obtained from sensitized rats (33-66 M) and interleukin-13-evoked eotaxin generation from cultured rat mesothelial cells (16 -33 M) but not eosinophil chemotaxis. This work demonstrates that the annexin 1 mimetic peptide Ac2-26 prevents allergen-evoked eosinophilic inflammatory response in rats. Combined analysis of the in vivo and in vitro experiments presented herein suggests that the blockade of secretion of pivotal mediators for the allergic response, such as histamine and eotaxin, could be responsible for the inhibitory actions displayed by peptide Ac2-26.

The treatment of acute and chronic liver failure is still a challenge despite modern therapeutic innovations. While liver transplantation can restore liver function and improve patient survival, donor shortages limit this treatment to a small number of patients. Cellular xenotransplantation has emerged as an alternative for treating liver failure. Xenohepatocytes could be readily available in sufficient quantities to treat patients in critical condition and thereby reduce the donor shortage. The use of isolated encapsulated or non-encapsulated cells can reduce the immunorejection response. Several studies using animal models of acute or chronic liver failure have demonstrated improved survival and recovery of liver function after xenotransplantation of adult hepatocytes. Porcine liver cells are a potential source of xenohepatocytes due to similarities with human physiology and the great number of hepatocytes that can be obtained. The recent development of less immunogenic transgenic pigs, new immunosuppressive drugs, and cellular encapsulation systems represents important advances in the field of cellular xenotransplantation. In this study, we review the work carried out in animal models that deals with the advantages and limitations of hepatocyte xenotransplantation, and we propose new studies needed in this field.

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ATP physiologically activates the P2X7 receptor (P2X7R), a member of the P2X ionotropic receptor family. When activated by high concentrations of ATP (i.e., at inflammation sites), this receptor is capable of forming a pore that allows molecules of up to 900 Da to pass through. This receptor is upregulated in several diseases, particularly leukemia, rheumatoid arthritis and Alzheimer's disease. A selective antagonist of this receptor could be useful in the treatment of P2X7R activation-related diseases. In the present study, we have evaluated several parameters using in vitro protocols to validate a high-throughput screening (HTS) method to identify P2X7R antagonists. We generated dose-response curves to determine the EC50 value of the known agonist ATP and the ICs50 values for the known antagonists Brilliant Blue G (BBG) and oxidized ATP (OATP). The values obtained were consistent with those found in the literature (0.7 ± 0.07 mM, 1.3-2.6 mM and 173-285 μM for ATP, BBG and OATP, respectively). The Z-factor, an important statistical tool that can be used to validate the robustness and suitability of an HTS assay, was 0.635 for PI uptake and 0.867 for LY uptake. No inter-operator variation was observed, and the results obtained using our improved method were reproducible. Our data indicate that our assay is suitable for the selective and reliable evaluation of P2X7 activity in multiwell plates using spectrophotometry-based methodology. This method might improve the high-throughput screening of conventional chemical or natural product libraries for possible candidate P2X7R antagonist or agonist