Abstract
Purpose: :
To assess intraocular levels of VEGF in response to intravitreal Bevacizumab in different stages of Proliferative Diabetic Retinopathy (PDR) and in exudative Age related Macular Degeneration (eAMD).
Methods: :
Aqueous humour levels of VEGF (pg/ml) were measured prior to- and 21 days post intravitreal Bevacizumab (1.25 mg/injection) by using an ELISA Kit, in different stages of activity of PDR (n=43 eyes) and in eAMD (n=10 eyes).
Results: :
Aqueous humour VEGF levels were lower in controls 160.53±62.61 than in PDR 428.25±249.81 or eAMD 301.14±219.86. VEGF levels were correlated to the disease severity in PDR groups: severe PDR without severe exudation 678.19±199.23, severe PDR with severe exudation 3230.66±1935.99, moderate PDR (mPDR) 322.06±101.21, mild PDR (rPDR) 192.84±56.38. Laser treatment (LT) decreased VEGF level in PDR lasered groups: not LT mPDR 322.06±101.21 - lasered mPDR 204.8±24.29, not LT rPDR 192.84±56.38 - lasered rPDR 149.06±35.02. After 21 days, intravitreal Bevacizumab decreased intraocular VEGF levels in PDR group from 626.17±221.72 to 246.02±222.03 (p=0.016) and in eAMD group from 303.23±187.31 to 131.19±34.47 (p=0.019). However, individual values suggested that this evolution is not observed when VEGF levels are under certain limits. Compensatory mechanisms are suspected to protect VEGF.
Conclusions: :
Intraocular VEGF activity reflects disease activity. Bevacizumab decreases the intraocular VEGF levels in PDR and eAMD, possibly when VEGF exceeds a physiologic level. Further studies will correlate alterations in VEGF activity to changes in the activity of other intraocular growth factors.
Clinical Trial: :
www.clinicaltrials.gov NCT00776763
Keywords: clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials