title: Laughter regulates gene expression in patients with type 2 diabetes.
abstract: BACKGROUND
  Positive emotions influence endocrinological and immunological response. This study examined the effect of laughter,as an expression of positive emotion, in terms of gene expression changes.
  
  
  METHODS
  Using a microarray technique, we analyzed the changes in expression of 18,716 genes from peripheral blood leukocytes in patients with type 2 diabetes, which were induced by laughter.
  
  
  RESULTS
  Of the 18,716 genes, 23 genes showed significantly different expression changes after listening to the comic story compared to the lecture. Eight were relatively upregulated and 15 were downregulated 1.5 h after the laughing episode. However, these genes did not include genes that are directly involved in blood glucose metabolism. Among the 23 genes discriminated, all 4 genes encoding proteins involved in the immune response and all 4 signal transduction genes were downregulated. Moreover, it is noteworthy that 5 of the 8 relatively upregulated genes were related to the cell cycle, apoptosis, and cell adhesion.
  
  
  CONCLUSIONS
  We demonstrated that laughter, which is an expression of positive emotion, is linked to gene expression. However, the finding of this study does not allow reasonable interpretation for the regulation of gene expression by laughter. A more focused study is needed that may identify the candidate genes for the association between physical condition and positive emotion.
authors.affiliation: Foundation for Advancement of International Science, Bio-Laboratory, Tsukuba, Japan. hayashi@fais.or.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Hayashi
authors.forename: Osamu
authors.initials: O
authors.lastname: Urayama
authors.forename: Koichi
authors.initials: K
authors.lastname: Kawai
authors.forename: Keiko
authors.initials: K
authors.lastname: Hayashi
authors.forename: Shizuko
authors.initials: S
authors.lastname: Iwanaga
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ohta
authors.forename: Toshiro
authors.initials: T
authors.lastname: Saito
authors.forename: Kazuo
authors.initials: K
authors.lastname: Murakami
mesh_terms: D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics*; D015536:Down-Regulation; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007845:Laughter; D008297:Male; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D015398:Signal Transduction