Abstract
Purpose :
Chronic ocular graft-versus-host disease (oGvHD) is mainly an ocular surface disease associated with severe dry eye and inflammation. Patients with oGvHD often present with dilated (blood) vessels of conjunctiva and lid margins. In a murine model of Sjögren’s syndrome an increase in lymphatic vessels (LV) in the conjunctiva was observed. Since these mice show marked phenotypic similarities with mice with graft-versus-host disease (GvHD) including pronounced lid margin alterations, we analyzed LV in a murine model of GvHD in order to determine whether lymphangiogenesis is involved in the pathogenesis of oGvHD.
Methods :
After lethal total body irradiation (TBI, 13 Gy), CB6F1 hosts received 2.5 x 106 bone marrow cells from haploidentical BALB/c mice either alone (BMT mice), or in combination with 5 x 106 splenocytes for induction of GvHD (GvHD mice). 35 eyes were harvested with appending upper and lower lid margin and embedded in paraffin on day 11-12 (n=4 eyes), day 18-21 (n=17) and day 25-28 (n=14) after BMT. 2 µm sections of the lid margins were incubated with polyclonal anti-LYVE1 primary antibody as specific lymphatic endothelial marker and AP-conjugated secondary antibody. Four visual fields (40x) were photographed from each section, two from the upper and lower lid margin, respectively. In each visual field, the number of LV was manually counted and the area covered by LV (including lumina) analyzed using Image J.
Results :
The area covered by LV in the lid margins of GvHD mice was significantly increased in eyes harvested on day 11-12 (p=0.05), day 18-21 (p=0.007) and day 25-28 (p=0.013) after BMT compared to BMT mice without GVHD. However, the number of LV was not significantly different in both groups. Neither group showed significant progression over time for number or area of LV.
Conclusions :
LV seem to be altered in ocular GvHD as we demonstrated in a murine model of GvHD. The increase in LV area, but not in LV number comparing GvHD mice to BMT controls without GvHD, might be related to dilatation of the existent LV. However, the BMT itself may also lead to vessel alterations due to the TBI. Further investigations will have to show, if ocular GvHD is associated with active lymphangiogenesis.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.