Atrial natriuretic peptide in the vitreous humor and epiretinal membranes of patients with proliferative diabetic retinopathy.
OBJECTIVE
Atrial natriuretic peptide (ANP) has been recently described as an endogenous inhibitor of the synthesis and angiogenic action of vascular endothelial growth factor (VEGF). Given VEGF's key role in promoting neovascularization in proliferative diabetic retinopathy (PDR), this study was designed to evaluate the possibility that ANP could be involved in the neovascular and fibrotic complications of PDR.


METHODS
We determined ANP by radioimmunoassay in plasma and vitreous humor samples collected from diabetic patients with and without PDR and from non-diabetic subjects. ANP was also immunohistochemically localized in the epiretinal membranes of patients with PDR.


RESULTS
Vitreous ANP concentrations were significantly higher in patients with active PDR compared to patients with quiescent PDR, diabetes without PDR or controls <0.05. Significant differences were also observed between vitreous ANP levels in diabetic patients without PDR and control subjects. There was no significant correlation between serum and vitreous ANP levels in any of the patient groups. ANP was detected in the fibrovascular epiretinal tissue of patients with PDR.


CONCLUSIONS
Diabetic patients with active neovascularization have significantly higher levels of ANP in the vitreous humor than those without active PDR. Diabetic patients without PDR were also found to have significantly higher vitreous ANP levels than non-diabetic patients. Since plasma and vitreous ANP concentrations were found to be unrelated, we suggest intraocular ANP synthesis and/or an increase in the release of ANP into the vitreous, as opposed to diffusion from the blood, as the main factors contributing to the high vitreous ANP levels observed in diabetic patients. In the fibrovascular epiretinal tissue of these patients, ANP was found to be localized in vascular, glial, fibroblast-like and retinal pigment epithelium cells. Our findings suggest a role for ANP in PDR.
Unidad de Investigación, Departamento de Medicina Interna III, Hospital Clinico San Carlos, Madrid, Spain.
Raquel
R
Rollin
Aránzazu
A
Mediero
Juan Carlos
JC
Martínez-Montero
Manuela
M
Roldán-Pallarés
Marta
M
Suárez-Leoz
Pilar
P
Vidal-Fernández
Carlos
C
Cortés-Valdés
Arturo
A
Fernández-Cruz
Raquel
R
Fernández-Durango
D000328:Adult; D000368:Aged; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000378:metabolism* / Q000601:surgery; D019773:Epiretinal Membrane / Q000378:metabolism* / Q000601:surgery; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D007633:Keratins / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D015861:Retinal Neovascularization / Q000378:metabolism; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism*
D005904:Glial Fibrillary Acidic Protein; D007633:Keratins; D009320:Atrial Natriuretic Factor