Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

Table 1 The ABCB1, ABCC2 and ABCG2 mRNA and protein levels in intestinal tissue from patients with ulcerative colitis

		Controls	Inactive disease				Active disease				Ref.
		Colon	Colon	P value	Rectum	P value	Colon	P value	Rectum	P value
Gene	ABCB11	1 (ref)	NA	NS	NA		22%	< 0.001	34%	< 0.01	[72]
	ABCC21	1 (ref)	NA	NS	NA		NA	NS	NA	NS	[72]
	ABCG21	1 (ref)	NA	NS	NA		11%	< 0.001	16%	< 0.001	[72]
Array	ABCB12	287	-1.5								[40]
	ABCC22	81	-8.6								[40]
Protein	ABCG23	100 (9/9)	80 (53/67)				24 (13/54)	0.01			[73]

¹The ABCB1, ABCC2 and ABCG2 mRNA levels in colon and rectum tissue from patients with ulcerative colitis in remission (n = 17) or with active disease (n = 16) compared to the levels in colon tissue from healthy controls (n = 17). mRNA levels are normalised to the villin mRNA level. P values compared to the expression in the controls;

²Microarray analyses of pooled cRNA from uninflamed colonic tissue from 4 patients with UC and 4 control subjects. Fold change expression in colon tissue compared to controls. Statistically significant expression levels of ABCB1 were found in UC patients compared to controls by RT-PCR analyses using 18S RNA as internal control (P < 0.05);

³Quantitative immunohistochemistry of formalin-fixed paraffin-embedded (FFPE) colonic biopsies from 9 healthy individuals and 36 patients with ulcerative colitis. The values are n % (samples with positive staining/total number). P value for active colitis compared to controls and inactive colitis, respectively. NA: Not available; NS: Not significant.