ABSTRACT
BACKGROUND: Here, we ask whether platelet GPIb and GPIIb/IIIa receptors modulate platelet sequestration and activation during GalTKO.hCD46 pig lung xenograft perfusion. METHODS: GalTKO.hCD46 transgenic pig lungs were perfused with heparinized fresh human blood. Results from perfusions in which αGPIb Fab (6B4, 10 mg/l blood, n = 6), αGPIIb/IIIa Fab (ReoPro, 3.5 mg/l blood, n = 6), or both drugs (n = 4) were administered to the perfusate were compared to two additional groups in which the donor pig received 1-desamino-8-d-arginine vasopressin (DDAVP), 3 µg/kg (to pre-deplete von Willebrand Factor (pVWF), the main GPIb ligand), with or without αGPIb (n = 6 each). RESULTS: Platelet sequestration was significantly delayed in αGPIb, αGPIb+DDAVP, and αGPIb+αGPIIb/IIIa groups. Median lung "survival" was significantly longer (>240 vs. 162 min reference, p = 0.016), and platelet activation (as CD62P and ßTG) were significantly inhibited, when pigs were pre-treated with DDAVP, with or without αGPIb Fab treatment. Pulmonary vascular resistance rise was not significantly attenuated in any group, and was associated with residual thromboxane and histamine elaboration. CONCLUSIONS: The GPIb-VWF and GPIIb/IIIa axes play important roles in platelet sequestration and coagulation cascade activation during GalTKO.hCD46 lung xenograft injury. GPIb blockade significantly reduces platelet activation and delays platelet sequestration in this xenolung rejection model, an effect amplified by adding αGPIIb/IIIa blockade or depletion of VWF from pig lung.
Subject(s)
Blood Platelets/cytology , Lung/metabolism , Platelet Aggregation/genetics , Platelet Glycoprotein GPIIb-IIIa Complex/metabolism , Platelet Glycoprotein GPIb-IX Complex/metabolism , von Willebrand Factor/metabolism , Animals , Animals, Genetically Modified , Graft Survival/immunology , Heterografts/immunology , Humans , Lung/immunology , Lung Transplantation/methods , Platelet Activation/physiology , Platelet Aggregation/immunology , Platelet Glycoprotein GPIb-IX Complex/genetics , Swine , Thrombocytopenia/etiology , Transplantation, Heterologous/methods , von Willebrand Factor/geneticsABSTRACT
We report enrichment in the efficiency of generating mice transgenic for expression of a human protein in their milk using GFP-mediated preimplantation screening. The transgene array consisted of a functional gene (human alpha-1 antitrypsin under the control of the ovine BLG promoter) linked 5' to a reporter gene (GFP under the control of the murine Oct-4 promoter). GFP expression was detected in blastocysts by fluorescence microscopy and green and nongreen embryos were transferred to recipients in separate groups. In the first experiment, of seven pups that resulted from the transfer of blastocysts expressing GFP, five (71%) were transgenic. The experiment was repeated and of 12 pups that resulted from transfer of GFP-expressing blastocysts, 11 were transgenic (92%). The presence of the reporter cassette used for preimplantation screening did not affect the expression level of alpha-1-antitrypsin in the milk of the transgenic mice. In addition, in a related experiment wherein the GFP reporter gene was co-injected with a second mammary-specific transgene, pINC, no effect on transgene expression was observed. For mice transgenic for the mammary-specific gene alone, expression levels for four different lines were 192, 197, 382, and 415 microg/mL. For mice transgenic for both the mammary-specific transgene and the Oct4-GFP reporter cassette, expression levels for seven different lines were 282, 321, 468, 497, 499, 516, and 806 microg/mL.
Subject(s)
Blastocyst/physiology , Gene Expression Profiling , Luminescent Proteins/genetics , Mice, Transgenic/genetics , Promoter Regions, Genetic , Transcription Factors , Animals , Cattle , DNA-Binding Proteins/genetics , Female , Green Fluorescent Proteins , Humans , Lactoglobulins/genetics , Male , Mice , Mice, Transgenic/physiology , Octamer Transcription Factor-3 , Pregnancy , alpha 1-Antitrypsin/geneticsABSTRACT
Since the first report of live mammals produced by nuclear transfer from a cultured differentiated cell population in 1995 (ref. 1), successful development has been obtained in sheep, cattle, mice and goats using a variety of somatic cell types as nuclear donors. The methodology used for embryo reconstruction in each of these species is essentially similar: diploid donor nuclei have been transplanted into enucleated MII oocytes that are activated on, or after transfer. In sheep and goat pre-activated oocytes have also proved successful as cytoplast recipients. The reconstructed embryos are then cultured and selected embryos transferred to surrogate recipients for development to term. In pigs, nuclear transfer has been significantly less successful; a single piglet was reported after transfer of a blastomere nucleus from a four-cell embryo to an enucleated oocyte; however, no live offspring were obtained in studies using somatic cells such as diploid or mitotic fetal fibroblasts as nuclear donors. The development of embryos reconstructed by nuclear transfer is dependent upon a range of factors. Here we investigate some of these factors and report the successful production of cloned piglets from a cultured adult somatic cell population using a new nuclear transfer procedure.
