Investigation of prolactin-related vasoinhibin in sera from patients with diabetic retinopathy.
OBJECTIVE
In vitro experiments and in vivo studies on rodents demonstrate that N-terminal 14, 15, 16, 17, and 18 kDa fragments prolactin-related vasoinhibin (PRL-V) of human PRL are natural inhibitors of neovascularization in the retina and elsewhere. These N-terminal PRL fragments belong to a family of peptides named vasoinhibins, which act as endogenous regulators of angiogenesis and vascular function. These observations led to the hypothesis that PRL-V could play a role in the pathophysiology of diabetic retinopathy in humans. The purpose of this study was to investigate whether patients with diabetes mellitus and diabetic retinopathy have aberrant concentrations of PRL-V in the circulating blood.


METHODS
We performed a case-control study and developed a new technique to semi-quantitatively determine PRL-V in serum samples from 48 male subjects. The case group consisted of 21 patients with diabetes mellitus and proliferative or non-proliferative diabetic retinopathy. The control group consisted of 27 healthy subjects with no history of diabetes mellitus.


METHODS
For the detection of PRL-V, we developed a new analytical method, consisting of immunologic and laser-induced fluorescence techniques. Results The case group had significantly lower PRL-V serum concentrations than the control group (P=0.041). There was no significant difference between patients with proliferative and those with non-proliferative diabetic retinopathy.


CONCLUSIONS
We conclude that given the antiangiogenic and antivasopermeability actions of PRL-V, the decreased serum levels of PRL-V in patients with diabetes mellitus could contribute to the development and progression of diabetic retinopathy.
Triebel
Jakob
J
Department of Gastroenterology and Endocrinology, Center of Internal Medicine, Georg-August-University, Robert-Koch-Strasse 40, 37075 Göttingen, Germany. jakob.triebel@gmx.de
Huefner
Michael
M
Ramadori
Giuliano
G
D000368:Aged; D016022:Case-Control Studies; D018797:Cell Cycle Proteins / Q000097:blood*; D003920:Diabetes Mellitus / Q000097:blood*; D003930:Diabetic Retinopathy / Q000097:blood*; D018604:Epitope Mapping; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D008163:Luminescent Measurements / Q000379:methods; D008297:Male; D044085:Microfluidics / Q000379:methods; D008875:Middle Aged; D011388:Prolactin / Q000097:blood
D018797:Cell Cycle Proteins; C493181:VASH1 protein, human; D011388:Prolactin