Original Article

Application of Topical/Subconjunctival Bevacizumab and Topical Fluorometholone Acetate in Alkali Burn-induced Model of Corneal Angiogenesis

10.4274/tjo.40.318

  • Ayşen Topalkara
  • Mustafa İlker Toker
  • Feyza Dursun
  • Ayşe Vural Özeç
  • Mustafa Kemal Arıcı
  • Ayhan Dursun

Turk J Ophthalmol 2010;40(6):318-322

Objective:

Insulin resistance (IR) and associated metabolic abnormalities are increasingly being reported in the adolescent population. Cut-off value of homeostasis model of assessment IR (HOMA-IR) as an indicator of metabolic syndrome (MS) in adolescents has not been established. This study aimed to investigate IR by HOMA-IR in urban Indian adolescents and to establish cut-off values of HOMA-IR for defining MS.

Methods:

A total of 691 apparently healthy adolescents (295 with normal body mass index (BMI), 205 overweight, and 199 obese) were included in this cross-sectional study. MS in adolescents was defined by International Diabetes Federation (IDF) and Adult Treatment Panel III (ATP III) criteria. IR was calculated using the HOMA model.

Results:

Mean height, waist circumference (WC), waist/hip ratio (WHR), waist/height ratio (WHtR), and blood pressure were significantly higher in boys as compared to girls. The HOMA-IR values increased progressively from normal weight to obese adolescents in both sexes. Mean HOMA-IR values increased progressively according to sexual maturity rating in both sexes. HOMA-IR value of 2.5 had a sensitivity of >70% and specificity of >60% for MS. This cut-off identified larger number of adolescents with MS in different BMI categories (19.7% in normal weight, 51.7% in overweight, and 77.0% in obese subjects) as compared to the use of IDF or ATP III criteria for diagnosing MS. Odds ratio for having IR (HOMA-IR of >2.5) was highest with WHtR (4.9, p <0.0001) and WC (4.8, p <0.0001), compared to WHR (3.3, p <0.0001).

Conclusions:

In Indian adolescents, HOMA-IR increased with sexual maturity and with progression from normal to obese. A HOMA-IR cut-off of 2.5 provided the maximum sensitivity and specificity in diagnosing MS in both genders as per ATP III and IDF criteria.

Material and Method:

Twenty-four Wistar albino rats were used in our study. After chemical cauterization of the cornea, the rats were divided randomly into four groups. Group 1 (control group) received artificial tears twice a day, group 2 received topical fluorometholone acetate twice a day, in group 3, a single dose of bevacizumab (2.5 mg) was administered by a subconjunctival injection, and group 4 received topical bevacizumab 5mg/ml twice a day. Three weeks later, the rat corneas were evaluated by slit-lamp biomicroscopy and corneal photographs were taken with a digital camera, followed by sacrifice of the subjects. The proportional area of vascularized cornea, length of the longest neovascular sprout, corneal oedema and corneal opacity score were assessed.

Result:

The analysis of digital photographs showed less corneal neovascularization, corneal oedema, corneal opacity score and shorter length of the longest neovascular sprout in the three drug groups than in the control one (p<0.05). The area of corneal neovascularization in groups 3 and 4 was less than in group 2 (p=0.035 and p=0.027, respectively). Corneal neovascularization, corneal oedema and corneal opacity did not differ significantly between the subconjunctival and topical bevacizumab groups. However, statistically significant decrease was observed in the length of the longest neovascular sprout in the topical bevacizumab group (p=0.029).

Discussion:

Subconjunctival/topical bevacizumab treatment is an effective method in reducing corneal neovascularization. However, we observed that topical bevacizumab is more efficient than subconjunctival bevacizumab and fluorometholone acetate in preventing corneal neovascularization.

Keywords: Corneal neovascularization, bevacizumab, vascular endothelial growth factor VEGF, fluorometholone acetatet

Full Text (Turkish)