Evaluation of potential immune response and in vivo survival of riboflavin-ultraviolet light-treated red blood cells in baboons.

BACKGROUND: Pathogen reduction methods have the potential to modify blood components, resulting in immunologic reactions or compromised blood components. This study evaluated the hypothesis that there is no immune response to riboflavin-and-ultraviolet [UV]-light-treated red blood cells (RBCs), as observed by serology and by survival of RBCs in circulation. STUDY DESIGN AND METHODS: Three baboons were in each treatment group: 1) untreated (negative control), 2) quinacrine mustard (QM)-treated (positive control), and 3) riboflavin-and-UV light-treated (test group) RBCs. In the immunization phase, autologous test or control RBCs were injected subcutaneously on Days 0, 21, 42, and 49. Plasma samples from these days were tested against test or control RBCs by flow cytometry and standard serology. On Day 56, autologous (51)Cr-labeled test or control RBCs were injected. Blood samples were taken over 21 days after injection to determine RBC survival (t(1/2)). RESULTS: Untreated and riboflavin-and-UV-light-treated RBCs showed no evidence of significant immunoglobulin G (IgG) binding after incubation with autologous plasma. RBC-bound IgG was detected on QM-treated RBCs after incubation with autologous plasma. This antibody was inhibited by QM, as demonstrated by a hapten inhibition study. t(1/2) values for the untreated and riboflavin-and-UV-light-treated RBCs were 7.3 +/- 0.8 and 7.5 +/- 1.7 days, respectively; the t(1/2) value for QM-treated RBCs was 2.3 +/- 2.9 days. CONCLUSION: Treatment with riboflavin and UV light did not render RBCs immunogenic. Positive controls indicated that immunization promoted an immune response. In the (51)Cr-labeled RBC survival phase of the study, riboflavin-and-UV-light-treated RBCs exhibited behavior similar to negative control RBCs. Detrimental immunologic or functional side effects were not observed.

Reduction of prion infectivity in packed red blood cells.

The link between a new variant form of Creutzfeldt-Jakob disease (vCJD) and the consumption of prion contaminated cattle meat as well as recent findings showing that vCJD can be transmitted by blood transfusion have raised public health concerns. Currently, a reliable test to identify prions in blood samples is not available. The purpose of this study was to evaluate the possibility to remove scrapie prion protein (PrP(Sc)) and infectivity from red blood cell (RBC) suspensions by a simple washing procedure using a cell separation and washing device. The extent of prion removal was assessed by Western blot, PMCA and infectivity bioassays. Our results revealed a substantial removal of infectious prions (3 logs of infectivity) by all techniques used. These data suggest that a significant amount of infectivity present in RBC preparations can be removed by a simple washing procedure. This technology may lead to increased safety of blood products and reduce the risk of further propagation of prion diseases.

Generation of tyrosine hydroxylase positive neurons from human embryonic stem cells after coculture with cellular substrates and exposure to GDNF.

Tyrosine hydroxylase (TH)-positive neurons were generated from human embryonic stem (hES) cells by coculturing on astrocytes or PA6 stromal cells. After 3 to 4 weeks in culture, TH-positive cells with neuronal morphology developed. Coculture with astrocytes from the embryonic striatum produced a larger number of TH-positive cells than did coculture with astrocytes from embryonic mesencephalon (329 +/- 149 versus 33 +/- 16 TH-positive cells per well, p < .05). In other experiments using PA6 cells as a substrate, glial-derived neurotrophic factor (GDNF) was added to the media of differentiating hES cells, and this led to a doubling of the number of TH-positive cells (PA6: 443 +/- 105 TH-positive cells per well versus PA6 + GDNF: 934 +/- 136, p < .05). We conclude that substrates of striatal astrocytes and PA6 cells can promote differentiation of human embryonic stem cells to a TH-positive phenotype and that GDNF can increase the number of cells expressing that phenotype.

Propentofylline after focal cortical lesion in the rat: impact on functional recovery and basic fibroblast growth factor expression.

The effects of propentofylline, a xanthine derivative and adenosine transport inhibitor, were evaluated following anteromedial cortex lesion in the rat. Propentofylline (2x/10 mg/kg, intraperitoneally) was administered for 7 days post-insult and basic fibroblast growth factor (bFGF) immunoreactivity measured at designated time points in the peri-lesional cortex and ipsilateral dorsal striatum. The spatiotemporal pattern of bFGF expression was then compared to functional recovery patterns. Propentofylline-treated animals displayed increased bFGF expression in the peri-lesional cortex which may have contributed to the observed early facilitation of functional recovery. Drug administration did not, however, produce a change in bFGF expression in the ipsilateral dorsal striatum compared to saline-treated animals. These findings taken together with other positive findings regarding propentofylline, support the drug's therapeutic potential.