Different physiological parameters of the skin will be measured before, during and after the six-month space mission by non-invasive instruments. The series of skin physiological measurements were carried out on a single astronaut. The study investigated possible changes in skin parameters like hydration (via Corneometry), barrier function (via measurements of the trans epidermal water loss - TEWL) and skin topography (via SELS – Surface Evaluation of the Living Skin, VisioScan). In addition to these epidermal measurements which were regularly done on the ISS by the astronaut, before and after the mission dermal parameters like the elasticity (by Cutometry) and the density of the skin were recorded. For the latter ultrasound device (DermaScan C) with a frequency of 20 MHz was used.
Volare mission during ISS Expeditions 35/36 and 37/38
Skin B experiment
Results of the space experiment show changes in the skin as follows:
Concerning the epidermal parameters in space, an apparently slight increase of hydration could be shown; it is also a common phenomenon in aging skin. This can be interpreted in relation to the thinning of corneal layers in aging skin and the measuring principle of Corneometry by means of the condensator method. Due to the thinning, deeper parts of the epidermis with more water are measured, which leads to higher hydration values. But overall pre-flight values compared to postflight values showed a slight decrease in skin hydration. The transepidermal water loss increased during the space mission, which shows an impairment of the barrier function of the skin and implies a loss of integrity of the basal lamina. With respect to the Surface Structure of the skin, an increased coarsening of the skin fields has been found. This is also found in aging skin . This could be due to a decreased turnover of epidermal cells from the basal layer up to the stratum corneum and would also explain why the epidermis gets thinner. An explanation of these phenomena might be the flattening of the interface between dermis and epidermis which causes less surface area for proliferative stem cells in the stratum basale [1,8]. In contrast to the epidermal effects which are reminiscent of aging effects both the biological elasticity and the elastic properties of the dermis increased. This might be due to fluid shifts in weightlessness . However the far more important change observed after the mission was a severe degradation of the dermal connective tissue. This gets apparent through large amorphous low-echo zones on ultrasound images of the skin obtained two weeks after the end of the mission. This is considered not to be due to inactivity like in paraplegia, since corresponding ultrasound images would happen to look different .
Due to logistical and technical reasons and also because the measurements were carried out on only one subject, further tests with more test subjects, using optimised test conditions and additional measuring methods (e.g. for the determination of capillary blood flow and oxygen saturation of hemoglobin) are necessary. This way, the general medical risks can be determined via skin physiological parameters and the side effects on the skin due to long-term stay in space can be minimised (Tronnier et al. 2008).
R.M. Lavker, P.S. Zheng, G. Dong, (1987), "Aged skin: a study by light, transmission electron, and scanning electron microscopy", Journal of Investigative Dermatology, 88, 3 Suppl, pp. 44s-51s.
K.A. Kirsch, F.J. Baartz, H.C. Gunga, L. Röcker, (1993), "Fluid shifts into and out of superficial tissues under microgravity and terrestrial conditions", Journal of Clinical Investigation, 71, 9, pp. 687-689.
H. Tronnier, M. Wiebusch, U. Heinrich, R. Stute, (1999), "Surface evaluation of living skin", Advances in Experimental Medicine and Biology, 455, pp. 507-516.
K. Ivanova, N.H. Zadeh, I. Block, P.K. Das, R. Gerzer, (2004), "Stimulation of cyclic GMP efflux in human melanocytes by hypergravity generated by centrifugal acceleration", Pigment Cell Research, 17, 5, pp. 471-479.
D. Risin, (2008), "Evidence Report on: Risk of Inability to Adequately Treat an Ill or Injured Crewmember", Human Research Evidence Book 2008, Exploration Medical Capability (ExMC) Element, NASA, Johnson Space Center, Houston, Texas, http://humanresearchroadmap.nasa.gov/Evidence/reports/ExMC.pdf.
H. Tronnier, M. Wiebusch, U. Heinrich, (2008), "Change in Skin Physiological Parameters in Space - Report on and Results of the First Study on Man", Skin Pharmacology and Physiology, 21, pp. 283-292.
H. Tronnier, M. Wiebusch, U. Heinrich, (2008), "First Skin Physiological Tests in Weightlessness in the ISS Space Station", International Federation of the Societies of Cosmetic Chemists, 11, 3, pp. 231-238.
S. Mine, N.O. Fortunel, H. Pageon, D. Asselineau, (2008), "Aging alters functionally human dermal papillary fibroblasts but not reticular fibroblasts: a new view of skin morphogenesis and aging", Public Library of Science ONE, 3, 12, pp. e4066.
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Demonstration of the use of the Corneometer device (ground model). Photo: ISS Lab Ruhr GmbH
Demonstration of the use of the VisioScan device (ground model). Photo: ISS Lab Ruhr GmbH
The ground model of the Tewameter hardware. Photo: ISS Lab Ruhr GmbH