Table 3– Metabolites that significantly correlate with markers of emphysema (FV950) and systemic inflammation (C-reactive protein (CRP) and fibrinogen)#
Biochemical pathway/processBMIFFM
PosNegPosNegCRP PosFibrinogen PosFV950 Pos+
His metabolism, muscle protein catabolism§3MH, His3MH
BCAA degradationVal, Leu, Ile, 3HIB, ISBVal, Leu, IleVal, Leu, Ile, ISB, 3AIB
Cr biosynthesis/Gly degradation§Arg, GuanCn, DMGGly, CrCr, Cn, Gly, Guan, Bet, ChCn
Phe and Tyr metabolism§TyrPhe, Tyr, PAG (microbial)Phe
Ala, Asp+Glu/Gln+Glu metabolism§Ala, Asp, Glu, GlnGluAla, Asp, GluGln
Arg and Pro metabolism§ ArgPro
Lys degradation§Lys, AKAAKA
Energy metabolism including glycolysis, gluconeogenesis and TCA cycleLac, Pyr, GlcGlc, Cac,
Cit, Ac
Ketone bodies3HB3HIB, AcAc, Aco3HIB
Nicotinate/nicotinamide metabolismNMA
Acetylated glycoproteinsOAc, NAcOAc, NAcOAc, NAcNAc
VitaminsAscMyoAscScyllo
Lipid metabolismHDL, LDL/VLDL, TG, MG, Poly, GlclLDL/VLDL, PolyMG, GlyclTG, MG, PC, Glycl
Microbial metabolism (gut flora); TMA/methane metabolismTMAForm
  • No negative correlations were observed with CRP or fibrinogen. BMI: body mass index; FFM: fat-free mass; Pos: positive; Neg: negative; BCAA: branched-chain amino acids; Cr: creatine: Gly: glycine; Phe: phenylalanine; Tyr: tyrosine; Ala: alanine; Asp: aspartate; Glu: glutamate; Gln: glutamine; Arg: arginine; Pro: proline; Lys: lysine; TCA: tricarboxylic acid; TMA: trimethylamine; Val: valine; Leu: leucine; Ile: isoleucine; 3HIB: 3-hydroxyisobutyrate; ISB: isobutyrate; Guan: guanidinoacetate; Lac: lactate; Pyr: pyruvate; Glc: glucose; 3HB: 3-hydroxybutyrate; OAc: O-acetylglycoprotein; NAc: N-acetylglycoprotein; Asc: ascorbate; HDL: high-density lipoprotein; LDL: low-density lipoprotein; VLDL: very low-density lipoprotein; TG: triglyceride; MG: monoglycerides; Poly: polyunsaturated lipid; Glycl: glycerol; NMA: N-methylnicotinic acid; Cn: creatinine; DMG: N,N-dimethylglycine; 3MH: 3-methylhistidine; His: histidine; 3AIB: 3-aminoisobutyrate; Bet: betaine; Ch: choline; PAG: phenylacetylglycine; AKA: α-ketoadipate; Cac: cis-aconitate; Cit: citrate; Ac: acetate; AcAc: acetoacetate; Aco: aconitate; Myo: myo-inositol; PC: phosphorylcholine; Form: formate; Scyllo: scyllo-inositol; form: formate. #: full data including correlation coefficient values are shown in table S5; : percentage of lung pixels with low attenuation on the whole lung scans with attenuation values of <-950 HU; +: higher FV950 values indicated greater emphysema; §: amino acid metabolites generated and utilised during protein synthesis and degradation.