تنظیم بیان ژن های یوگا، مدیتیشن و شیوه های مربوط: مروری بر مطالعات اخیر

Integrative medicine (IM) approaches have gained significant interest in recent years to provide a solution for the health care challenges we face today. Yogic cognitive-behavioral practices are among the most widely used IM approaches and include diverse practices such as yoga asanas, meditation, breathing exercises, Qi Gong, Tai Chi Chih, and various others. Studies to date suggest that these yogic/meditative practices have significant positive effects on the mind–body system and thereby can increase wellness and support the healing process from disease. Previous work has provided evidence for both psychological and physiological effects of these practices; however, the mechanisms of these effects, especially at the molecular level, have largely been missing. Three recent studies started to provide some of this information through gene expression profiling in circulating immune cells, which support the hypothesis that yogic/meditative practices have a measurable effect at the molecular level. These studies are reviewed herein and some future perspectives are considered.

The current health care delivery systems in the Western world have significant challenges, not only in terms of the dramatically escalating costs, but also in terms of the quality of health care provided (America, 2001, Blendon et al., 2001, Taylor, 2001 and Snyderman and Weil, 2002). This is, at least in part, the reason for the increasing interest in integrative medicine (IM) approaches to health and wellness (Snyderman and Weil, 2002, Barnes et al., 2008 and Nahin et al., 2009). In addition to providing the best possible conventional care, IM focuses on preventive maintenance of health with emphasis on diet, lifestyle, stress management, and emotional well-being (Snyderman and Weil, 2002). IM encourages patients to be active participants in their health care, as well as asking physicians to view patients with all aspects of their being, and not only physical bodies (Snyderman and Weil, 2002). To achieve these goals, in addition to depending on the latest in scientific findings and evidence based approaches, IM taps on time-tested traditional modalities to increase health and wellness, as well as helping treat disease states, at least as adjunct regimens. One of the most widely used IM approaches is yogic cognitive-behavioral practices, including yoga asanas, meditation, breathing exercises, Qi Gong, Tai Chi Chih, etc. (referred to as yogic/meditative practices from now on). In general, these practices stem from Asia, although similar practices may be found in many traditions in other parts of the world. The increasingly wide use of these practices triggered numerous research studies, especially in recent decades, which suggest that yogic/meditative practices have significant positive effects on the mind–body system and thereby can increase wellness and support the healing process from disease (for reviews, see Astin et al., 2003, Arias et al., 2006, Bushell et al., 2009 and Kuntsevich et al., 2010). For example, studies on meditative therapies suggested that they can effectively reduce psychological distress which in turn can have important clinical implications in nonpsychotic mood and anxiety disorders (for reviews, see da Silva et al., 2009, Gangadhar and Varambally, 2011 and Chen et al., 2012). The general understanding is that psychosocial distress is linked to various disease states, such as depression, cardiovascular disease, and cancer, as well as its more well-appreciated role in psychiatric disorders (Cohen et al., 2007); yogic/meditative practices effectively counter psychological distress and thereby support healing and wellness (Arias et al., 2006, Chen et al., 2012, da Silva et al., 2009 and Gangadhar and Varambally, 2011). The effects of yogic/meditative practices extend to physiological parameters such as humoral factors, the nervous system and the immune system (for reviews, see Arias et al., 2006, Ospina et al., 2007 and Kuntsevich et al., 2010). For example, these practices were shown to have positive effects on the heart rate, blood pressure, and low density lipoprotein (LDL) cholesterol, and decrease the levels of salivary cortisol, the ‘stress hormone’. These findings are consistent with a downregulation of the hypothalamic–pituitary–adrenal (HPA) axis and the sympathetic nervous system (SNS) both of which are known to be over activated by our western lifestyle. In addition, yogic/meditative practices increase vagal activity (Bernardi et al., 2001); together with the effects on the HPA axis and SNS, they could thus have favorable immune and endocrine outcomes. For example, a two-month hatha yoga intervention resulted in a 22% and 20% reduction, respectively, in the proinflammatory cytokine interleukin-6 (IL-6) and C-reactive protein (CRP), compared to minimal changes in chronic heart failure patients receiving standard medical care (Pullen et al., 2008). Furthermore, a yoga breathing based program resulted in increased antioxidant enzyme production (Sharma et al., 2003). Despite these and numerous other studies, the exact physiological mechanisms that may give rise to the psychological and physiological effects of yogic/meditative practices are currently unknown. In particular, the molecular and cellular mechanisms of these wide-ranging effects, from psychological states to brain activity to immune function, are not known and a systems biology approach is required to precisely map the exact pathways involved. Recent studies started to provide some of this information through pathway specific or global gene expression profiling in polymorphonuclear cells (PBMCs) or neutrophils from the blood, the tissue which is most easily available for this type of investigation in humans. Below is a brief overview of this approach and a description of the three published studies to date on yogic/meditative practices using gene expression profiling, their comparative analysis, and some future perspectives.

It is now well established that there are distinct gene expression changes induced by the environment, not only by physical influences, but also via psychological, social, and cultural components, studied by the emerging field of pscyhosocial genomics (for a review, see Garland and Howard, 2009). For example, previous work on social genomics has suggested that adverse life experiences give rise to significant changes in gene expression in circulating immune cells (for a review, see Cole, 2010). The first set of studies on yogic/meditative practices reviewed above are consistent with this framework and suggest that these practices positively affect gene expression profiles in immune cells in the circulation demonstrating that the ‘mind–body’ practices may benefit the physiology at its most fundamental level. More detailed studies are required to evaluate the validity of these findings and the precise molecular networks that are responsible for the gene expression patterns that are observed upon yogic/meditative practices and their possible therapeutic efficacy. Gene expression profiling can also have utility in comparative analysis of different practices, such as different types of meditation, and help delineate the different effects that they may induce at the molecular to systemic levels.