Gene Expression Microarrays in Microgravity Research: Toward the Identification of Major Space Genes

Crewmembers of space flights commonly experience certain health condition changes such as immune system dysregulation, musculoskeletal changes (e.g., significant bone and muscle loss), and neurological alterations. Since the space exploration of the 1960s and 1970s, physiological changes in several organ systems due to weightlessness have been identified. Some of the adverse effects are a decline in cellular immune responses (Leach et al, 1990; Cogoli 1993; Pippia et al; 1996; Borchers et al, 2002;), cardiovascular deconditioning (Fritsch-Yelle, et al 1996), bone deterioration (Mack et al 1967; Vose et al 1974; Atkov 1992; Schneider et al, 1995; Collet et al, 1997) and muscular atrophy (Thomason and Booth 1990; Aubers et al, 2005; Trappe et al, 2009). Human exposure to microgravity has been demonstrated to be a major environmental factor during space flight (Cogoli et al 1993; Ullrich et al, 2008). Many of the adverse effects of microgravity have much in common with earthbound health problems related to low physical activity or less mechanical loading. For example, bone and muscle loss as well as immune system dysfunction are some of the main consequences common to both extended spaceflight and physical inactivity such as that associated with the aging population and people suffering from degenerative disorders. In a recent review article, mechanotransduction is attributed as the possible convergence point for all the “abnormalities” associated with aging and microgravity because human adaptation to microgravity has all the features of accelerated aging (reviewed by Vernikos & Schneider 2010). More recently, similarities between the clinical presentation (such as atrophy in muscle and bone, cardiovascular disturbances, and alterations in renal, immune and sensory motor systems) of individuals living with spinal cord injury (SCI) and those who experience prolonged gravity unloading (especially astronauts) are reviewed (Scott et al, 2011). It is evident that continued effort in microgravity research will deeper our understanding of space adaptation response and improve many of our health-related problems on earth. Thus, microgravity based research can further our understanding of human diseases such as SCI, diabetes, osteoporosis and premature aging that are related to physical inactivity. Most effective counter measures can then be formulated to ensure safe experience in microgravity and promote healthy beings especially at the senior level.