Overexpression of Hypoxia-Inducible Factor-1α in Primary Graft Dysfunction Developing in an Orthotopic Lung Transplantation Rat Model.

BACKGROUND: Primary graft dysfunction (PGD) is the major cause of early morbidity and mortality after transplantation. A high rate of PGD is a frequent complication in orthotopic lung transplantation (OLT) models, which are currently used to investigate acute and chronic rejection pathways. Hypoxia-inducible factor (HIF)-1α is a heterodimeric αß transcription factor that mediates tissue response to hypoxia. In other solid organ transplantations, a significant correlation between HIF-1α expression and PGD was detected. To our knowledge no data are available on HIF-1α expression in PGD developing in lung transplantation. The aims of this study were to investigate HIF-1α expression (using immunohistochemistry) and correlate it to the main histological parameters related to ischemia-reperfusion (IR) injury, including terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) -positive apoptotic cells). METHODS: OLT was performed in 32 inbred rat strains and 11 of them died in the early postoperative period (from day 0-3) for IR injury. The histological and molecular evaluations were done in all lung tissues. Unimplanted donor rat lungs were used as controls. HIF-1α expression was correlated with all morphological parameters. RESULTS: Lung samples of animals with IR injury showed high scores of HIF-1α expression, edema, blood extravasation, granulocyte margination, apoptotic index, and necrosis in 91% of cases. Tissue overexpression of HIF-1α was detected in all lung samples with high scores of histological parameters and with high apoptotic indexes. CONCLUSION: Our data demonstrate that HIF-1α was overexpressed in more severe rat lung IR injury. The use of HIF-1α inhibitors could provide a translatable route into manipulating this complex system in vivo.

Posttransplant Lymphoproliferative Disorders in Neuronal Xenotransplanted Macaques.

Posttransplant lymphoproliferative disorders (PTLDs) are a heterogeneous group of lymphoid proliferations that occur in the setting of depressed T-cell function due to immunosuppressive therapy used following solid organ transplantation, hematopoietic stem cell transplantation, and also xenotransplantation. In the present study, 28 immunosuppressed parkinsonian Macaca fascicularis were intracerebrally injected with wild-type or CTLA4-Ig transgenic porcine xenografts to identify a suitable strategy to enable long-term cell survival, maturation, and differentiation. Nine of 28 (32%) immunosuppressed primates developed masses compatible with PTLD, located mainly in the gastrointestinal tract and/or nasal cavity. The masses were classified as monomorphic PTLD according to the World Health Organization classification. Immunohistochemistry and polymerase chain reaction (PCR) analyses revealed that the PTLDs were associated with macaca lymphocryptovirus as confirmed by double-labeling immunohistochemistry for CD20 and Epstein-Barr nuclear antigen 2 (EBNA-2), where the viral protein was located within the CD20+ neoplastic B cells. In sera from 3 distinct phases of the experimental life of the primates, testing by quantitative PCR revealed a progression of the viral load that paralleled the PTLD progression and no evidence of zoonotic transmission of porcine lymphotropic herpesvirus through xenoneuronal grafts. These data suggest that monitoring the variation of macaca lymphocryptovirus DNA in primates could be used as a possible early diagnostic tool for PTLD progression, allowing preemptive treatment such as immunosuppression therapy reduction.

Cell Therapy for Parkinson's Disease: A Translational Approach to Assess the Role of Local and Systemic Immunosuppression.

Neural transplantation is a promising therapeutic approach for neurodegenerative diseases; however, many patients receiving intracerebral fetal allografts exhibit signs of immunization to donor antigens that could compromise the graft. In this context, we intracerebrally transplanted mesencephalic pig xenografts into primates to identify a suitable strategy to enable long-term cell survival, maturation, and differentiation. Parkinsonian primates received WT or CTLA4-Ig transgenic porcine xenografts and different durations of peripheral immunosuppression to test whether systemic plus graft-mediated local immunosuppression might avoid rejection. A striking recovery of spontaneous locomotion was observed in primates receiving systemic plus local immunosuppression for 6 mo. Recovery was associated with restoration of dopaminergic activity detected both by positron emission tomography imaging and histological examination. Local infiltration by T cells and CD80/86+ microglial cells expressing indoleamine 2,3-dioxigenase were observed only in CTLA4-Ig recipients. Results suggest that in this primate neurotransplantation model, peripheral immunosuppression is indispensable to achieve the long-term survival of porcine neuronal xenografts that is required to study the beneficial immunomodulatory effect of local blockade of T cell costimulation.

The immunological barriers to xenotransplantation.

The availability of cells, tissues and organs from a non-human species such as the pig could, at least in theory, meet the demand of organs necessary for clinical transplantation. At this stage, the important goal of getting over the first year of survival has been reported for both cellular and solid organ xenotransplantation in relevant preclinical primate models. In addition, xenotransplantation is already in the clinic as shown by the broad use of animal-derived medical devices, such as bioprosthetic heart valves and biological materials used for surgical tissue repair. At this stage, however, prior to starting a wide-scale clinical application of xenotransplantation of viable cells and organs, the important obstacle represented by the humoral immune response will need to be overcome. Likewise, the barriers posed by the activation of the innate immune system and coagulative pathway will have to be controlled. As far as xenogeneic nonviable xenografts, increasing evidence suggests that considerable immune reactions, mediated by both innate and adaptive immunity, take place and influence the long-term outcome of xenogeneic materials in patients, possibly precluding the use of bioprosthetic heart valves in young individuals. In this context, the present article provides an overview of current knowledge on the immune processes following xenotransplantation and on the possible therapeutic interventions to overcome the immunological drawbacks involved in xenotransplantation.

The antimetastatic drug NAMI-A potentiates the phenylephrine-induced contraction of aortic smooth muscle cells and induces a transient increase in systolic blood pressure.

The ruthenium-based drug imidazolium trans-imidazoledimethylsulphoxidetetrachlorido ruthenate (NAMI-A) is a novel antitumour drug under clinical evaluation. In this study, NAMI-A is tested on aortic rings in vitro and on the systolic blood pressure in vivo with the aim of evaluating its effects on smooth muscle cells and, more in general, on the vascular system. Pre-incubation of aortic rings with 10 µM NAMI-A for 10 min potentiates the contraction induced by phenylephrine (PE). The reduction of the B max value of [(3)H]-prazosin bound to NAMI-A-treated aortic rings and the ability of NAMI-A to displace [(3)H]-prazosin and [(3)H]-IP3 binding by 25 and 42%, respectively, suggest the involvement of α1-adrenoceptor in mediating the effects on smooth muscle cells. NAMI-A also decreases the number of maximal sites of [(3)H]-prazosin bound to kidney membrane preparation from 34 to 24 fmol/mg proteins. A single i.p. dose (105 mg/kg) or a repeated treatment for 6 consecutive days (17 mg/kg/day) in Wistar rats increases the systolic blood pressure, respectively, 1 h and 3 days after treatment, and the responsiveness of rat aortic rings to PE. Atomic absorption spectroscopy confirms the presence of ruthenium in the aortic rings excised from the treated rats. These findings suggest monitoring the cardiovascular parameters when the drug is used in humans for treating cancer patients, particularly if the drug is associated with chemicals that are potentially active at the cardiovascular level.

5-aryl-imidazo[2,1-c][1,4]benzodiazepine derivatives as tricyclic constrained analogues of diazepam and Ro5-4864. Synthesis and binding properties at peripheral and central benzodiazepine receptors.

Four series of 5-aryl-imidazo[2,-c][1,4]benzodiazepine derivatives 1a-f, 2a-f, 3a-f, and 4a-f were synthesized and tested for their affinity at both the peripheral and central benzodiazepine receptors. Among the four series, only N-10 and C-11 sites were changed, mainly [N(CH3)-CO], [N=CH], [NH-CO], [NH-CH2], and in each series the halogen site was varied at the positions C-7, C-2', and C-4'. In particular, 10-methyl-benzodiazepinones 1a and 1b were designed as tricyclic constrained analogues of diazepam and Ro5-4864. All the tested compounds did not show significant binding activity at central benzodiazepine receptors, but relatively good PBzR binding affinities were found for 10-methyl-benzodiazepinone 1c and benzodiazepines 2b, c. Benzodiazepinones 3a-f were prepared by cyclization with 1,1'-carbonyldiimidazole of the corresponding 2-(aryl-imidazol-1-yl-methyl)-arylamines, obtained from the suitable (2-amino-aryl)-aryl-methanols with 1,1'-carbonyldiimidazole in different conditions. N-Alkylation of 3a-f to 1a-f was achieved using dimethylformamide-dimethylacetal. Reduction of 3a-f to 4a-f was accomplished with lithium aluminum hydride or borane and oxidation of 4a-f to 2a-f was performed with manganese (IV) oxide.

Isolation of a murine metastatic cell line and preliminary test of sensitivity to the anti-metastasis agent NAMI-A.

We have isolated a new cell line (metGM) obtained from the spontaneous lung metastases of the mouse MCa mammary carcinoma. MetGM is a stable cell line which, after one year from its isolation, grows in vitro in suspension, forming cell aggregates, with cells that show irregular blabbing borders, active protein synthesis and convoluted nuclei and which have the capacity of invading matrigel membranes on which they give rise to a network of branching colonies. The preliminary study of the effects of the anti-metastasis ruthenium complex NAMI-A on metGM showed no direct cytotoxicity, with a mild reduction of cell proliferation, independent of the concentration of the ruthenium complex and not evident before 24 hours from treatment. A 10% DNA fragmentation was also measured on metGM cells 24 hours after challenge for 1 hour with 10(-5)M NAMI-A, suggesting that this compound is probably capable of apoptosis in a metastasis-derived cell line. Besides these effects on a limited percent of the cell population, NAMI-A changed the shape of the metGM cells and these alterations might account for the non-cytotoxic anti-metastatic properties of this innovative ruthenium complex. Thus MetGM appears to be a novel cell line suitable for the in vitro study of compounds endowed with anti-metastatic properties and for the development of new drugs with this activity.

In vitro down regulation of ICAM-1 and E-cadherin and in vivo reduction of lung metastases of TS/A adenocarcinoma by a lysozyme derivative.

The aim of the present investigation was to examine the effects of the lysozyme derivative mPEG-lyso (hen egg-white lysozyme coupled with polyoxyethylenglycol), on TS/A adenocarcinoma cell line in vivo and in vitro. mPEG-lyso reduces the number of ICAM-1+ and E-cadherin+ cells of TS/A adenocarcinoma cell line in vitro, and causes a marked decrease of spontaneous lung metastases in vivo. In both cases, mPEG-lyso reduces the number of tumour cells in sythesis and pre-mitotic phases. In connection with the reduction of cells expressing adhesion molecules, mPEG-lyso reduces the number of infiltrating leukocytes in the primary tumour in vivo and reduces the binding capacity of splenocytes to tumour cells in vitro. These data stress, for the first time, that the in vivo control of mPEG-lyso on lung metastasis formation of solid metastasising tumours may be due to a combination of effects on tumour cells in addition to those on host's immune system.