Current application of proteomics in biomarker discovery for inflammatory bowel disease

Table 3 Proteomic studies for discovering inflammatory bowel disease management biomarkers

Ref.	Bio-sample	Sample size	Proteomic technique	Results
Disease activity biomarkers
Han et al[34]	Intestinal tissue	CD: 3	LC-QTOF	16 proteins distinguishing active/inactive CD
		UC: 4		4 proteins distinguishing active/inactive UC
		Inflammatory Polyps: 2
		Normal colon: 3
Wasinger et al[39]	Serum	UC: 27	MRM	SPP24 was able to differentiate active and quiescent disease in both UC and CD
		CD: 56
		Controls: 14
		RA controls: 12
Prognostic biomarkers
May et al[57]	Intestinal epithelial cells	Non-dysplastic tissue from non-progressors: 5	High-performance liquid chromatography quadrupole -TOF	155 candidate proteins were expressed differentially by > 2x between dysplastic/cancerous and non-dysplastic UC tissue. They were identified as mitochondrial, cytoskeletal, apoptotic and RAS superfamily proteins
		Non-dysplastic tissue from progressors: 5
		Highly dysplastic tissue from UC progressors: 5
Response to therapy biomarkers
Meuwis et al[37]	Serum	Infliximab responders: 40	SELDI-TOF	3 proteins (PF4, sCD40L and IL-6) were identified infliximab non-responders, although PF4 and sCD40L could not be confirmed or correlated with ELISA
		Infliximab non-responders: 40
Kanmura et al[23]	Blood samples	CD: 22	SELDI-TOF	Plasma concentration of HNP1, 2 and 3 decreased following successful corticosteroid therapy compared to non-responders
		UC: 48
		Colorectal cancer: 5
		Infectious colitis: 6
		Healthy controls: 13
Gazouli et al[38]	Serum	Infliximab responders: 6	2-DE, MALDI-TOF	7 proteins were increased in CD patients who did not achieve remission on infliximab. 4 were increased in patients who achieved remission. 3 proteins were lower in remission patients
		Infliximab non-responders: 6
		Infliximab partial responders: 6

CD: Crohn’s disease; UC: Ulcerative colitis; IBD: Inflammatory bowel disease; MRM: Multiple reaction monitoring.