Table 1.

Summary of microbially produced uremic toxins, class, precursor, property, and related toxic effect.

Name	Class	Precursor	Characteristics	Conventional HD Reduction Rate (%)	Effect of PBUTs	Ref
Indoxyl sulfate	Indoles	Tryptophan	PBUT	30%	CVD, vascular injury, bone disease, and nephrotoxicity	[46,47,48,49]
Indole3 Acetic Acid	Indoles	Tryptophan	PBUT	40%	Cardiovascular dysfunction, endothelial damage, and cognitive impairment	[50,51,52]
Kynurenine, kynurenic acid, quinolinic acid	Kinurenine pathway	Tryptophan	PBUT	20%	Cardiovascular dysfunction and cognitive impairment	[53,54]
Hippuric Acid	Hippurates	Benzoic acid	PBUT	60–70%	Renal fibrosis and endothelial dysfunction	[55,56]
P-cresyl sulfate	Phenols	Tyrosine	PBUT	30%	Cardiovascular damage, renal tubular injury, and insulin resistance	[57,58,59]
P-cresyl glucuronide	Phenols	Tyrosine	PBUT	70%	Vascular damage	[60]
TMAO	Amine oxide	Choline, betaine, carnitine	Water-soluble compound	80%	CVD and renal inflammation	[61,62,63]

Abbreviations: HD, hemodialysis; PBUTs, protein-bound uremic toxins; CVD, cardiovascular disease.