BackgroundSuccessful treatment of acute radiation syndromes relies on immediate supportive care. In patients with limited hematopoietic recovery potential, hematopoietic stem cell (HSC) transplantation is the only curative treatment option. Because of time consuming donor search and uncertain outcome we propose MSC treatment as an alternative treatment for severely radiation-affected individuals.Methods and FindingsMouse mesenchymal stromal cells (mMSCs) were expanded from bone marrow, retrovirally labeled with eGFP (bulk cultures) and cloned. Bulk and five selected clonal mMSCs populations were characterized in vitro for their multilineage differentiation potential and phenotype showing no contamination with hematopoietic cells. Lethally irradiated recipients were i.v. transplanted with bulk or clonal mMSCs. We found a long-term survival of recipients with fast hematopoietic recovery after the transplantation of MSCs exclusively without support by HSCs. Quantitative PCR based chimerism analysis detected eGFP-positive donor cells in peripheral blood immediately after injection and in lungs within 24 hours. However, no donor cells in any investigated tissue remained long-term. Despite the rapidly disappearing donor cells, microarray and quantitative RT-PCR gene expression analysis in the bone marrow of MSC-transplanted animals displayed enhanced regenerative features characterized by (i) decreased proinflammatory, ECM formation and adhesion properties and (ii) boosted anti-inflammation, detoxification, cell cycle and anti-oxidative stress control as compared to HSC-transplanted animals.ConclusionsOur data revealed that systemically administered MSCs provoke a protective mechanism counteracting the inflammatory events and also supporting detoxification and stress management after radiation exposure. Further our results suggest that MSCs, their release of trophic factors and their HSC-niche modulating activity rescue endogenous hematopoiesis thereby serving as fast and effective first-line treatment to combat radiation-induced hematopoietic failure.

Summary. Plants attacked by herbivorous insects emit a blend of volatile compounds that serve as important host location cues for parasitoid wasps. Variability in the released blend may exist on the whole-plant and within-plant level and can affect the foraging efficiency of parasitoids. We comprehensively assessed the kinetics of herbivore-induced volatiles in soybean in the context of growth stage, plant organ, leaf age, and direction of signal transport. The observed patterns were used to test the predictions of the optimal defence hypothesis (OD). We found that plants in the vegetative stage emitted 10-fold more volatiles per biomass than reproductive plants and young leaves emitted >2.6 times more volatiles than old leaves. Systemic induction in single leaves was stronger and faster by one day in acropetal than in basipetal direction while no systemic induction was found in pods.Herbivore-damaged leaves had a 200-fold higher release rate than pods. To some extent these findings support the OD: i) indirect defence levels were increased in response to herbivory and ii) young leaves, which are more valuable, emitted more volatiles. However, the fact that reproductive structures emitted no constitutive or very few inducible volatiles is in seeming contrast to the OD predictions.We argue that in case of volatile emission the OD can only partially explain the patterns of defence allocation due to the peculiarity that volatiles act as signals not as toxins or repellents.2

The combination of angiogenic inhibitors was superior to single factors, suggesting additive activity. These data support the strategy of combining angiogenic inhibitors to accomplish a complete angiogenic blockade.