Table 1.

Alterations in TRPV1 and TRPA1 transcription/expression in Crohn’s disease (CD) patients with fold-changes where available. (IHC: immunohistochemistry, IF: immunofluorescence).

Disease Activity	Ion Channel	Sampling Method/Location	Methods	Results; Number of Patients	Relation to Abdominal Complaints and/or Disease severity	Ref
Active CD	TRPV1	Resection (colectomy)	IHC (computerized image analysis)	upregulated in submucosa; n = 6	Not reported	[31]
		Colon biopsy–affected and non-affected regions	IHC (computerized image analysis)	upregulated in mucosa and infiltrating inflammatory cells; n = 30	No significant correlation between disease severity and TRPV1 expression	[32]
		Distal colon biopsy	IHC, qPCR	downregulated mRNA n = not reported	Not reported	[33]
		Colon biopsy	IF	downregulated mRNA n = 6	Not reported	[37]
	TRPA1	Distal colon biopsy	IHC, qPCR	upregulated mRNA n = not reported	Not reported	[33]
		Colon biopsy	IF	upregulated mRNA n = 7	Not reported	[37]
CD in remission	TRPV1	Distal colon biopsy	IHC, qPCR	downregulated mRNA n = not reported	Not reported	[33]
		Rectosigmoid biopsy	IHC	upregulated in symptomatic quiescent patients; 3.9-fold increase in median number of TRPV1-immunoreactive fibers (CD and UC combined) n = 9	Significant correlation between TRPV1 expression and abdominal pain score	[35]
CD – disease activity unknown	TRPA1	Surgical samples of fibrotic regions (colon)	IHC	Denser immunoreactivity in mucosal and submucosal layers n = 3	Not reported	[38]
		Biopsy from fibrotic regions (colon)	IHC, RT-PCR	upregulated mRNA and protein levels n = 8	Not reported	[39]