Background We have previously demonstrated the presence of an embryonic stem cell (ESC)-like population localised to the endothelium of the microvessels and perivascular within keloid-associated lymphoid tissues (KALTs) in keloid lesions (KLs). We have also shown that this ESC-like population expresses components of the renin-angiotensin system (RAS). The observation of the association of vitamin D deficiency, hypertension and keloid disorder (KD) led us to investigate the expression of vitamin D receptor (VDR) by the ESC-like population in KLs.
Methods 11 formalin-fixed paraffin-embedded sections of KLs underwent 3,3-diminobenzidine (DAB) immunohistochemical (IHC) staining for VDR. Immunofluorescence (IF) dual IHC staining of CD34/VDR and OCT4/VDR was performed on two of these samples of KLs. Transcript expression of VDR was investigated in four representative snap-frozen KLs using reverse-transcription quantitative polymerase chain reaction (RT-qPCR).
Results DAB IHC staining demonstrated the presence of VDR on the KALTs within the keloid tissue samples. RT-qPCR confirmed transcript expression of VDR. IF IHC staining demonstrated expression of VDR on the CD34+ and the OCT4+ endothelium of the microvessels, and the OCT4+ perivascular cells, within the KALTs.
Discussion/Conclusions This study demonstrated the expression of VDR by the ESC-like population within the KALTs in KLs. Further work is needed to elucidate the precise interaction between VDR and the RAS in regulating the primitive population within KALTs.