Expression of placental growth factor, neuropilin-1, and neuropilin-2 in primary pterygium tissue

PURPOSE

The aim of this study was to evaluate the expression of placental growth factor (PLGF), neuropilin-1 (NP-1), and neuropilin-2 (NP-2) molecules in primary pterygium tissue compared with normal conjunctival tissue.

METHODS

The records of 42 patients who underwent excision surgery with autografts for primary pterygium (pterygium group) and 20 patients who underwent conjunctival nevus excision surgery (control group) in the same period were reviewed retrospectively. The samples obtained from the pterygium tissues in the pterygium group and the clean conjunctival tissues adjacent to the nevus in the control group were collected from the archive. Immunohistochemical stains of the primary antibodies-1/100 diluted PLGF, NP-1, and NP-2 (Abcam Cambridge Science Park, UK)-were applied to all groups. Staining intensities and the percentage of positive cells in epithelial, endothelial, stromal, and inflammatory cells were analyzed by an experienced pathologist.

RESULTS

The positivity rates of PLGF and NP-2 expression in epithelial, endothelial, stromal, and inflammatory cells were found to be higher in the pterygium group than in the control group (PLGF: p < 0.001, p < 0.001, p = 0.001, and p < 0.001, respectively; NP-2: p < 0.001 for all). Staining intensities for PLGF and NP-2 were higher in the pterygium group than in the control group (PLGF: p < 0.001, p < 0.001, p = 0.005, and p < 0.001, respectively; NP-2: p < 0.001, p < 0.001, p = 0.001, and p < 0.001, respectively). However, no significant differences were found in any cell type in terms of NP-1 expression positivity rates (p = 0.730, p = 0.121, p = 0.524, and p = 0.624, respectively) or staining intensity (p = 0.716, p = 0.147, p = 0.147, and p = 0.780, respectively).

CONCLUSION

PLGF and NP-2 levels were found to be higher in pterygium tissue, while there was no difference in NP-1. These results indicate the possible roles of NP-2 and PLGF in primary pterygium.

Isl1 is upstream of sonic hedgehog in a pathway required for cardiac morphogenesis

The LIM homeodomain transcription factor Islet1 (Isl1) is expressed in both foregut endoderm and cardiogenic mesoderm and is required for earliest stages of heart development. Here, we report that isl1 is also required upstream of Shh. We find that, in isl1 null mice, Sonic hedgehog (Shh) is downregulated in foregut endoderm. Shh signals through the unique activating receptor smoothened (Smo). To investigate the role of hedgehog signaling in the isl1 domain, we ablated smo utilizing isl1-cre. Isl1-cre;smo mutants exhibit cardiovascular defects similar to those observed in Shh null mice, defining a spatial requirement for hedgehog signaling within isl1 expression domains for aortic arch and outflow tract formation. Semaphorin signaling through neuropilin receptors npn1 and npn2 is required for aortic arch and outflow tract formation. We find that expression of npn2 is downregulated in isl1-cre;smo mutants, suggesting an isl1/Shh/npn pathway required to affect morphogenesis at the anterior pole of the heart.