TABLE 6.

Fold changes in fasted serum metabolite concentrations in astronauts with and without pathologic optical changes after flight

Outcome and metabolic pathway	Metabolite	Change
Disc edema, total n = 48
Histidine metabolism	1-Methylhistidine	1.30
	Imidazole propionate	1.64
	1-Methylimidazoleacetate	1.45
Methionine metabolism	2-Aminobutyrate	1.29
	Hypotaurine	1.80
	N-acetyltaurine	1.28
Lipid metabolism	2-Hydroxyadipate	1.63
	1-Palmitoylglycerophosphocholine (16:0)	1.26
	2-Palmitoylglycerophosphocholine	1.16
	1-Stearoylglycerophosphocholine (18:0)	1.28
	2-Stearoylglycerophosphocholine	1.22
	1-Oleoylglycerophosphocholine (18:1)	1.39
	1-Arachidonoylglycerophosphocholine (20:4n6)	1.27
	1-Stearoylglycerophosphoethanolamine	1.30
	1-Arachidonoylglycerophosphate	1.28
	Palmitoyl-arachidonoyl-glycerophosphocholine (2)	1.26
	Pimelate	1.52
Change in diopters, total n = 31
Carbohydrate metabolism	Mannose	1.21
	Galactonate	2.41
	Glucuronate	1.25
	N-acetylneuraminate	1.41
Inositol metabolism	Myo-inositol	1.27
	Chiro-inositol	2.42
	Scyllo-inositol	1.40
	Myo-inositol:chiro-inositol	0.52
Cotton wool spots, total n = 39
Steroid metabolism	Epiandrosterone sulfate	1.15
	5α-Androstan-3β,17β-diol monosulfate (2)	1.12
	5α-Androstan-3β,17β-diol disulfate	1.47
	5α-Androstan-3α,17β-diol monosulfate (2)	2.30
Xanthine metabolism	3,7-Dimethylurate	1.49
	3-Methylxanthine	1.62
	7-Methylxanthine	1.39

All of the fold changes in this table were significant at q < 0.2, or the metabolite was in a metabolic pathway in which at least 2 other metabolites were significant. P < 0.05.