Table 4.

The potential functional relevance of identified metabolites associated with diabetes and pre-term delivery

Metabolite	Association	Potential relevance to pathophysiological aspects of diabetes and pre-term delivery	References
Glu	Increased in DM	Activates N-methyl-D-aspartate receptors in β-cells, leading to acceleration of β-cell dysfunction and apoptosis induced by hyperglycemia	[36]
BCAA (valine, leucine, isoleucine)	Increased in DM	Promotes insulin resistance by modulating fatty acid oxidation, mTOR, JNK and IRS1 pathways	[39, 40]
Phosphatidylcholines	Decreased in DM	Serum antioxidants preventing lipoprotein oxidation	[41]
AA	Increased in DM	Arachidonic acid triggers insulin secretion, potentially increasing risk of insulin resistance	[42]
GCDCA	Increased in DM	Bile acids control gut bacteria overgrowth, species population, and protect the integrity of the intestinal barrier. Alterations in GCDCA can trigger diabetes	[43]
DG and TG containing C18:1 and C18:2	Increased in pre-term delivery	Serum linoleic acid is negatively correlated with visceral fat accumulation and risk of insulin resistance	[48]
TG17.2/36.4 and TG18.1/34.1	Best predictors of pre-term delivery	Remains to be investigated

Glu, glutamate; BCAA, branched chain amino acids; mTOR, The mammalian target of rapamycin; JNK, c-Jun N-terminal kinase; IRS-1, insulin receptor substrate 1; AA, arachidonic acid; GCDCA, Glycochenodeoxycholic Acid; DG, diacylglycerols; TG, triacylglycerols