National Report on Space Medicine Progress in 2010—2012

Accompanying the flourishing developments of China's manned spaceflight,space medicine has achieved great development during the past two years in China.In this paper,scientific research of space medicine and its application in China during 2010-2012 have been briefly introduced.

Progress of Space Medicine Research in China

With the approaching of the Chinese Space Station(CSS)era,the focus of space medicine applications and related research has shifted to addressing the astronauts’health support in long-duration spaceflights,including nutrition,countermeasure against the physiological effects of weightlessness,medical monitoring and support,psychology status,etc.,and accordingly the human experiments to simulate long-duration weightlessness have been carried out.Increasingly,basic research has been put forward in the key areas,such as space bone loss,cardiovascular dysfunction and the molecular mechanisms underlying radiobiological effects.Moreover,specific novel research fields,such as hypometabolism technology,were explored.The research projects in the field of space medicine experiment,as an important aspect of the Chinese Space Station’s application,have been officially approved and launched.

Peptidic Alginate-Based Hydrogels Demonstrate Chemotaxis and Expansion to Adipose Tissue Derived and Blood Derived Stem Cells

Biodegradable scaffolds have a major therapeutic advantage in regenerative medicine with their ability to include multiple compounds of drugs, growth factors and more recently, stem cells within the matrix. The scaffold can be programmed with mechanoresistive parameters targeted to the tissue to be replaced. Direct chemoattraction of in vivo stem cells to the implanted scaffold would be advantageous in the clinical setting. Large peptides such as vasculo-endothelial growth factor have demonstrated chemotaxis for angiogenesis from endothelial cells. This suggests other endogenous peptides may be present to directly attract stem cells to a scaffold. This exploratory study assessed if peptides from the blood peptidome would display chemotaxis to stem cells. Results showed that several short N-mer peptides demonstrated remarkable chemotaxis to blood and adipose tissue derived stem cells. Sodium alginate hydrogel was placed into 6-well, 24-well plate, and partitioned plates with channels between the wells. Connected wells were in series and spiked with peptides, biofluids containing stem cells and control wells. Images were recorded between three and nine days after incubation at 37°C. There were rapid migration and expansion of stem cells into the peptide wells. Cell analysis revealed activated stem cells on a number of parameters including autophagy, Ki67 and nitric oxide. Potentially, this enhanced method to bioscaffold design utilizing peptide chemoattraction could result in an improved approach for stem cell therapy and regenerative medicine applications. Specific patient groups (e.g. blood coagulation disorders) where surgery to acquire adipose tissue or bone marrow is contraindicated may benefit. In addition, the technology is portable and safe by using “on demand” peripheral blood derived stem cells and would be particularly suitable for specialized environments such as space medicine.

Human Adipose Stem Cells Exposed to Gamma Radiation and Inactivity (Stasis) Show Increased Cancer Markers and DNA Damage. A Preliminary Assessment of a Pharmaceutical Formulation to Reverse These Effects and Its Applications for Medical Radiotherapy and the Space Industry

Gamma radiation exposure and physical inactivity occur in medical radiotherapy patients and astronauts resulting in substantial deterioration of their health. At the molecular level, the radiation triggers elevated markers for DNA double-strand breaks and tumorigenicity. Cell stasis is a potential phenomenon associated with low physical activity in recovering cancer patients and astronauts. This preliminary study assessed parameters of stasis and gamma radiation on human adipose stem cells (ADSCs) that have important regenerative functions for the body. A prototype pharmaceutical formulation (PF) was tested to prevent and reverse the effects of radiation and stasis. ADSCs were subjected to short-term (1 - 5 days) and longer-term (8 - 25 days) stasis and radiation with a combined total exposure of alpha, beta and gamma radiation measured at 455 microSv/hr on the Geiger counter. Cell health markers were grouped for characteristics of cellular health (annexin, H2A.X, NO, ROS) and tumorigenicity potential (P13, Ki67, MAPK) that were measured with flow cytometry. Results showed PF to improve cell health in days 1 - 5 compared to stasis (p = 0.01) and radiation (p = 0.02), and PF reduced tumorigenicity compared with stasis (p = 0.018) and radiation (p = 0.03). For longer exposure (8 - 25 days) PF improved cellular health compared with stasis (p = 0.038) and showed a non-significant trend for decreasing radiation effects (p = 0.07). There was decreased tumorigenicity compared with stasis (p = 0.003) and radiation (p = 0.005). This preliminary evaluation of the PF showed it to have 88% (66/75) positive assay results (p < 0.00001 Chi-square) indicating three promising beneficial effects: 1) prevent cell/DNA damage, 2) reduce cancer risk, and 3) recover damaged and precancerous stem cells. The PF could have important applications for medical radiotherapy patients, astronauts and future space mining personnel. PF reduced carcinogenesis and DNA damage of stem cells by approximately 50% from radiation that was the microSievert equivalent of 4 months on board the International Space Station.