Abstract
Purpose: :
In vivo human and animal studies demonstrate that bone marrow derived endothelial precursor cells (EPCs) play a critical role in neovascularisation and generalized vascular repair. In humans circulating EPCs are being used for therapy to promote vascularisation and correct tissue ischaemia. These bone marrow derived stem cells are recruited to murine choroidal neovascularisation (CNV) and participate in the repair process. The major chemokine for EPC recruitment is SDF. SDF’s only known ligand is CXCR4. To better understand the possible involvment of this axis, we investigated the presence and distribution of SDF and CXCR4 in human CNV.
Methods: :
Sections of 22 surgically excised CNVs were examined by histochemistry and by immunohistochemistry; the latter method employing antibodies to SDF, CXCR4, cytokeratins, CD34 or CD68. The specimens were placed into four aetiological categories, namely; CNV complicating age related macular degeneration (AMD) (9), uveal melanoma (UM) (5), choroidal inflammation (4), idiopathic CNV (4).
Results: :
CXCR4 staining was found in all specimens. SDF staining was found in 7 specimens (AMD 3, UM 2, idiopathic 2). By collating the data for all specimens the most intense staining for CXCR4 and SDF was in the retinal pigment epithelial (RPE), elements of the CNV.
Conclusions: :
Both the ligand and receptor of the SDF /CXCR4 axis exist in human CNV, most notably in the RPE component. Stem cell recruitment by the SDF / CXCR4 axis may be involved in the formation of CNV, irrespective of CNV aetiology.
Keywords: choroid: neovascularization • immunohistochemistry • pathology: human