The role of mesenchymal stem cells in hematopoietic stem cell transplantation: prevention and treatment of graft-versus-host disease.

BACKGROUND: The use and effectiveness of hematopoietic stem cell transplantation (HSCT) are limited by lethal complications, i.e., acute and chronic graft-versus-host disease (aGVHD and cGVHD, respectively), in which immune cells from the donor attack healthy recipient tissues. GVHD presents both prophylactic and therapeutic challenges, and overall survival is poor. Mesenchymal stem cells (MSCs) show considerable promise in the treatment of GVHD because of their potential immunomodulatory activity. Multiple studies have been performed to explore the possible benefit of MSCs in GVHD, but the results of these studies are sometimes conflicting. Therefore, we performed a systematic review and meta-analysis to estimate the effect of MSC infusion on GVHD treatment and prevention. METHODS: We systematically searched the MEDLINE (PubMed), Cochrane Library, EMBASE, ClinicalTrials.gov, and SinoMed CBM databases to identify studies published before February 2018 involving patients with hematologic malignancies undergoing HSCT and receiving MSC-based or conventional therapy. We included studies if they reported on the outcomes of interest. RESULTS: Ultimately, 10 studies were selected from among 413 candidates. According to our meta-analyses, compared with conventional treatment, MSC therapy demonstrated substantial improvements in terms of complete response (CR) and overall survival for cGVHD. However, MSC therapy did not show substantial improvements in terms of engraftment, the incidence of aGVHD, relapse, death, death due to relapse, or death due to infection. Subgroup analyses showed that MSCs derived from the umbilical cord (U-MSCs) and MSC infusion after HSCT substantially improved engraftment and cGVHD incidence, whereas MSCs derived from bone marrow (B-MSCs) and MSC infusion before HSCT shows no improvement. In addition, B-MSCs and MSC infusion before HSCT tend to prolong engraftment time, as well as increase the rates of relapse and death. CONCLUSIONS: MSC infusion can reduce cGVHD but not aGVHD incidence and showed a positive effect in patients who already had aGVHD. For GVHD prevention, the use of U-MSCs and MSC infusion after HSCT were optimal for reducing cGVHD incidence and promoting engraftment, and might help decrease the incidence rate of relapse and death. However, B-MSCs and MSC infusion before HSCT may be harmful to patients and thus require serious consideration. A lack of robust evidence, owing to the small number of studies and small sample sizes, indicates a need for further high-quality clinical trials including large numbers of patients to validate our findings

Geochemistry of soil gas in the seismic fault zone produced by the Wenchuan Ms 8.0 earthquake, southwestern China

The spatio-temporal variations of soil gas in the seismic fault zone produced by the 12 May 2008 Wenchuan Ms 8.0 earthquake were investigated based on the field measurements of soil gas concentrations after the main shock. Concentrations of He, H2, CO2, CH4, O2, N2, Rn, and Hg in soil gas were measured in the field at eight short profiles across the seismic rupture zone in June and December 2008 and July 2009. Soil-gas concentrations of more than 800 sampling sites were obtained. The data showed that the magnitudes of the He and H2 anomalies of three surveys declined significantly with decreasing strength of the aftershocks with time. The maximum concentrations of He and H2 (40 and 279.4 ppm, respectively) were found in three replicates at the south part of the rupture zone close to the epicenter. The spatio-temporal variations of CO2, Rn, and Hg concentrations differed obviously between the north and south parts of the fault zone. The maximum He and H2 concentrations in Jun 2008 occurred near the parts of the rupture zone where vertical displacements were larger. The anomalies of He, H2, CO2, Rn, and Hg concentrations could be related to the variation in the regional stress field and the aftershock activity

Preseismic deformation associated with the 2014 Ms7. 3 Yutian earthquake derived from GPS data

Based on analysis of the GPS data during 1999–2007, 2009–2011, and 2011–2013 mainly from the Crustal Motion Obseration Network of China, we obtained the GPS horizontal velocity field, the GPS strain rate field, and the profiles across the southwestern segment of the Altyn Tagh Fault zone and its adjacent regions and identified the different characteristics of horizontal crustal deformation fields and profiles during different perods. The results show that, before the Februar 12, 2014, Ms7. 3 Yutian earhquake, the laevorotation deformation along the southwestern segment of the Altyn Tagh Fault zone increased about 3. 3 mm/a during 2011–2013, relative to that in 2009–2011, and the GPS strain rate field distributed in the southeastern segment of the Altyn Tagh Fault during 2011–2013 increased obviously. These abnormal changes may be regarded as precursors to the Ms7. 3 Yutian earhquake

Dynamics of Structural Dry Matter, Water Soluble Carbohydrates and Leaf Senescence Mediate the Response of Winter Wheat Yield to Soil Cover and Water Availability

Plastic film mulching often increases the yield of winter wheat in the Loess Plateau of China, but the physiological mechanisms are unclear, especially in response to the interaction between mulch and water supply. In this study, we investigated the interactive effects of initial soil water (dry, moderate, and wet), soil cover (plastic mulch, bare soil), and seasonal conditions on the dynamics of dry matter partitioning, water-soluble carbohydrates (WSC), and flag leaf senescence, and their relations with yield and its components. Plastic mulch increased dry matter accumulation at anthesis and maturity relative to bare soil, with no interaction with season or initial soil water. Allocation of dry matter to leaf, stem, and spike did not change with soil cover. Compared with bare soil, mulch increased WSC accumulation by 14% at anthesis and its translocation by 16%. Soil cover did not influence the senescence of flag leaf after anthesis as indicated by similar dynamics of the C:N ratio. Grain yield was higher under plastic mulch than bare soil in two out of three seasons, and was associated with a higher translocation amount of WSC and post-anthesis dry matter that linked grain weight, grain number, and harvest index

Dynamics of Structural Dry Matter, Water Soluble Carbohydrates and Leaf Senescence Mediate the Response of Winter Wheat Yield to Soil Cover and Water Availability

Plastic film mulching often increases the yield of winter wheat in the Loess Plateau of China, but the physiological mechanisms are unclear, especially in response to the interaction between mulch and water supply. In this study, we investigated the interactive effects of initial soil water (dry, moderate, and wet), soil cover (plastic mulch, bare soil), and seasonal conditions on the dynamics of dry matter partitioning, water-soluble carbohydrates (WSC), and flag leaf senescence, and their relations with yield and its components. Plastic mulch increased dry matter accumulation at anthesis and maturity relative to bare soil, with no interaction with season or initial soil water. Allocation of dry matter to leaf, stem, and spike did not change with soil cover. Compared with bare soil, mulch increased WSC accumulation by 14% at anthesis and its translocation by 16%. Soil cover did not influence the senescence of flag leaf after anthesis as indicated by similar dynamics of the C:N ratio. Grain yield was higher under plastic mulch than bare soil in two out of three seasons, and was associated with a higher translocation amount of WSC and post-anthesis dry matter that linked grain weight, grain number, and harvest index