Dose of intravitreal bevacizumab (Avastin) used as preoperative adjunct therapy for proliferative diabetic retinopathy.
ABSTRACT The purpose of this study was to examine the effect of lower than usual doses of intravitreal bevacizumab (Avastin) on vitreous vascular endothelial growth factor (VEGF) concentration and intraoperative bleeding when used as preoperative adjunct therapy in patients undergoing vitrectomy for proliferative diabetic retinopathy.
Fifty-two eyes (52 patients) with indications for vitrectomy were studied; 12 received bevacizumab, and 40 did not. The bevacizumab group was given a single intravitreal injection of bevacizumab (0.16-1.25 mg) 3 days before vitrectomy. Numbers of intraoperative coagulation spots administered for hemostasis were compared between the two groups. In both groups, vitreous samples were collected during vitrectomy, and VEGF levels were measured by enzyme-linked immunosorbent assay.
The VEGF concentration was 1880.1 +/- 1927.5 in the nonbevacizumab group and 24.9 +/- 25.1 in the bevacizumab group, and the difference was significant (P = 0.0001). Although VEGF concentrations were apparently lower at higher bevacizumab doses, no significant correlation was observed (r = 0.366, P = 0.2425). Numbers of intraoperative coagulation spots differed significantly between the bevacizumab (3.2 +/- 0.8) and nonbevacizumab (5.7 +/- 1.0) groups (P < 0.0001). In the bevacizumab group, there was no correlation between the number of intraoperative coagulation spots and the bevacizumab dose (r = 0.272, P = 0.3919).
When intravitreal bevacizumab was administered as preoperative adjunct therapy to patients undergoing vitrectomy for proliferative diabetic retinopathy, the lowest dose tested (0.16 mg) was as effective as the standard dose (1.25 mg) in reducing vitreous VEGF concentrations and also decreasing intraoperative bleeding as measured by the reduced number of coagulation spots.
Article: Angiofibrotic response to vascular endothelial growth factor inhibition in diabetic retinal detachment: report no. 1.[show abstract] [hide abstract]
ABSTRACT: OBJECTIVES To assess the effect of bevacizumab injection on connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF) in the ocular fluids of patients with diabetic traction retinal detachment, and to determine whether intraoperative and postoperative complications are decreased in eyes given adjunctive preoperative bevacizumab injection. METHODS Twenty eyes of 19 patients were randomized to receive intravitreal bevacizumab or sham injection 3 to 7 days before vitrectomy for severe proliferative diabetic retinopathy. We collected aqueous samples before injection and at the time of vitrectomy and extracted undiluted vitreous samples. RESULTS Five eyes had decreased vascularization of membranes from preinjection to the time of vitrectomy (all in the bevacizumab treatment arm). Median visual acuities were 20/400 in control eyes at baseline and postoperative month 3 (POM3) and 8/200 in the bevacizumab-treated group at baseline and 20/100 at POM3 (P = .30 between control and bevacizumab-treated groups at POM3). All retinas were attached at POM3. Vitreous levels of VEGF were significantly lower in the bevacizumab group than in the control group (P = .03). Vitreous levels of CTGF were slightly lower in the bevacizumab group compared with the control group, but this difference was not statistically significant (P = .38). Levels of CTGF in the aqueous were strongly correlated with CTGF levels in the vitreous of controls (Spearman correlation coefficient, 0.95 [P < .001]). CONCLUSIONS Intravitreal bevacizumab injection reduces vitreous levels of VEGF and produces a clinically observable alteration in diabetic fibrovascular membranes. Ocular fluid levels of CTGF are not significantly affected within the week after VEGF inhibition. Retinal reattachment rates and visual acuity are not significantly altered by preoperative intravitreal bevacizumab injection at POM3. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01270542.Archives of ophthalmology 09/2012; 130(9):1127-34. · 3.86 Impact Factor
Article: Expression of endoplasmic reticulum stress-related factors in the retinas of diabetic rats.[show abstract] [hide abstract]
ABSTRACT: Recent reports show that ER stress plays an important role in diabetic retinopathy (DR), but ER stress is a complicated process involving a network of signaling pathways and hundreds of factors, What factors involved in DR are not yet understood. We selected 89 ER stress factors from more than 200, A rat diabetes model was established by intraperitoneal injection of streptozotocin (STZ). The expression of 89 ER stress-related factors was found in the retinas of diabetic rats, at both 1- and 3-months after development of diabetes, by quantitative real-time polymerase chain reaction arrays. There were significant changes in expression levels of 13 and 12 ER stress-related factors in the diabetic rat retinas in the first and third month after the development of diabetes, Based on the array results, homocysteine- inducible, endoplasmic reticulum stress-inducible, ubiquitin-like domain member 1(HERP), and synoviolin(HRD1) were studied further by immunofluorescence and Western blot. Immunofluorescence and Western blot analyses showed that the expression of HERP was reduced in the retinas of diabetic rats in first and third month. The expression of Hrd1 did not change significantly in the retinas of diabetic rats in the first month but was reduced in the third month.Experimental Diabetes Research 01/2012; 2012:743780. · 1.20 Impact Factor