After intravitreal aflibercept injection , a significant upregulation of systemic PlGF could be observed in all treated patients ( 38.0 [ 31.0-44 .0 ] pg/mL after 1 week [ P < 0.001 ] and 16.0 [ 0.0-19 .0 ] pg/mL [ P = 0.005 ] after 4 weeks ) .