Background Understanding the dynamics from the gut-brain axis has clinical implications for physical and Nepicastat HCl mental health issues including weight problems and stress and anxiety. at 18-27 a few months of age. It had been hypothesized that kids would differ within their gut microbial framework as indicated by procedures of alpha and beta variety predicated on their temperamental features. Outcomes Among both boys and girls greater Surgency/Extraversion was associated greater phylogenetic diversity. In addition among boys only subscales loading on this composite scale were associated with differences in phylogenetic diversity the Shannon Diversity index (SDI) beta diversity and differences in abundances of and were observed in relation to Fear. Some differences in dietary patterns were observed in relation to temperament but these did not account for the observed differences in the microbiome. Conclusions Differences in gut microbiome composition including alpha diversity beta diversity and abundances of specific bacterial species were observed in association with temperament in toddlers. This study was cross-sectional and observational and therefore does not permit determination of the causal direction of Nepicastat HCl effects. However if bidirectional brain-gut relationships are present in humans in early life this may represent an opportunity for intervention relevant to physical as well as mental health disorders. Introduction Our bodies are colonized by trillions of bacteria known as the microbiome which reside in many niches of the human body including the gut skin vagina and oral cavity. There are remarkable differences in microbial communities across individuals (Huttenhower et al. 2012 The role of the gut microbiome in health is rapidly gaining attention; overall bacterial diversity as well as specific bacterial abundances in the gut have been implicated in not only obesity but also allergy asthma and inflammatory bowel disease among other conditions (Kinross et al. 2011 In addition to Rabbit Polyclonal to DNL3. affecting physical health a central role of the gut microbiome in regulating mood and behavior is emerging. Via communication along the gut-brain axis bacterial communities may affect both the hypothalamic-pituitary-adrenal (HPA) axis and central nervous system via cytokine and neurotransmitter production among other mediators (for review see Collins and Bercik 2009 Forsythe et al. 2010 Foster and McVey Neufeld 2013 Relatedly there is interest in the possibility of intervening on the gut microbiome to affect mental health disorders (Dinan and Cryan 2012 Foster and McVey Neufeld 2013 Conversely a causal direction from behavior to gut is also now clearly established. Stressor-induced activation of the autonomic nervous system affects gastric acid bile and mucus secretion as well as gut motility (Beckh and Arnold 1991 Shigeshiro et al. 2012 Soderholm and Perdue 2001 all factors that impact gut microbes (Boesjes and Brufau 2014 Drasar et al. 1969 Santos et al. 1999 Saunders et al. 2002 Sommer et al. 2014 Sommer and Backhed 2013 Tache and Perdue 2004 Moreover and studies demonstrate that microbial composition can Nepicastat HCl be altered through a direct recognition of stress hormones including norepinephrine and epinephrine (Freestone et al. 1999 Freestone et al. 2002 Lyte 2004 Lyte and Bailey 1997 Lyte et al. 2003 Lyte et al. 2011 Determining the dynamics of the behavior-gut associations in early life is important because many physical Nepicastat HCl and mental health conditions (e.g. obesity anxiety) have early life antecedents (Caspi et al. 1996 Parsons et al. 1999 and the gut microbiome may be more malleable in early versus later life (Clarke et al. 2013 Considerable changes in the structure of the gut microbiota occur during the first year of life in response to changing diet (i.e. introduction of solid foods) and environmental exposures (Dominguez-Bello et al. 2010 Favier et al. 2003 However by approximately two years of age profiles of gut microbiota resemble profiles found in adults (Koenig et al. 2011 Palmer et al. 2007 Once established these profiles are relatively stable; although the gut microbiome changes in response to illness diet and exposures such as antibiotics overall profiles and the majority of dominant microbes tend to revert back to the pre-exposure state after a given disruption has passed (David et al. 2014 De La Cochetiere et al. 2005 Dethlefsen et al. 2008 Nepicastat HCl Thus.