Diabetic macular edema (DME) is a common ocular complication of diabetes patients. It mainly involve macular which is closely related with visual function, thus DME is one of the major reasons causing visual impairment or blindness for diabetes patients. How to reduce the visual damage of DME is always a big challenge in the ophthalmic practice. In the past three decades, there are tremendous developments in DME treatments, from laser photocoagulation, antiinflammation drugs to antivascular endothelial growth factor therapy. However, the mechanism of DME development is not yet completely clear; every existing treatment has its own advantages and weaknesses. Therefore DME treatment still challenges us to explore further to reduce the DME damages.
Objective To observe the effects of dual targets intervention on the expression of vascular endothelial growth factor (VEGF) and connective tissue growth factor (CTGF) in diabetic rat retina. Methods Forty-eight Sprague -Dawley rats were randomly divided into control group (CON1 group) and diabetes mellitus group (DM group). The rats of DM group were induced with streptozotocin injection creating a diabetic model. Retinas were obtained at eight, 10, 12 weeks after DM induction from both groups. CTGF and VEGF mRNA levels were examined by realtime reverse transcriptionpolymerase chain reaction (RT-PCR). Based on the results of above experiments, 60 rats with same conditions were selected. Fifty rats were induced with streptozotocin injection creating a diabetic model, and 10 rats comprised the control group (CON2 group). Then the 50 diabetic rats were randomly divided into ranibizumab and CTGF shRNA dual targets intervention group, ranibizumab singletarget intervention group, CTGF shRNA singletarget intervention group and nonintervention group. Retinas were obtained at one week after intervention from all the groups. CTGF and VEGF mRNA levels were examined by RT-PCR. Results The levels of CTGF mRNA were significantly higher in DM group than that in CON1 group at the 8th weeks after DM induction, and this upregulation was maintained through the 12th week (t=-2.49, -2.67, -2.42;P＜0.05). There was no difference on VEGF mRNA levels between DM group and CON1 group at the 8th weeks after DM induction(t=-0.443,P=0.669). VEGF mRNA levels of DM group started to be significantly elevated over those in the CON1 group at the 10th week, and remained to be higher at the 12th week (t=-2.35, -2.57;P＜0.05). The VEGF mRNA of ranibizumab single-target intervention group was significantly lower than that in non-intervention group (t=-3.44,P=0.014), which was similar to CON2 group (t=-1.37,P＞0.05); however, the CTGF mRNA level was significantly increased as compared to the nonintervention group (t=2.48,P＜0.05). In the CTGF shRNA single-target intervention group, the levels of CTGF and VEGF mRNA were decreased as compared to the non-intervention group (t=0.23, -2.92;P＜0.05). In the ranibizumab and CTGF shRNA dual targets intervention group, the levels of CTGF and VEGF mRNA were decreased as compared to the non-intervention group (t=-6.09, -5.11;P＜0.001), which was similar to CON2 group (t=-1.16, 1.139; P＞0.05). Conclusions Both CTGF and VEGF gene expression are up-regulated in early diabetic rat retina, and the level of CTGF increased earlier than VEGF. Ranibizumab combined with CTGF shRNA could simultaneously reduce the level of CTGF and VEGF mRNA in diabetic rat retina.
Objective To observe the therapeutic effect of ultrasonic microbubble combined with bevacizumab (Avastin) on choroidal neovascularization induced by photocoagulation in rabbits.Methods CNV was induced by photocoagulation with argon laser in 30 rabbits (60 eyes).All of the rabbits underwent fundus fluorecein angiography (FFA) 21 days after photocoagulation; 6-8 hours later, 3 rabbits were randomly chosen to be executed to having the immunohistochemical examination.Twenty one days after photocoagulation, 27 rabbits were divided randomly into 3 groups: bevacizumb, ultrasonic microbubble + bevacizumb,and control group; each group has 9 rabbits (18 eyes).The rabbits in control group had no interference treatment; while the rats in bevacizumb and ultrasonic microbubble + bevacizumb group underwent injection with bevacizumb or ultrasonic microbubble + bevacizumb respectively.FFA was performed on all of the rabbits 7,14,and 28 days after photocoagulation to observe the inhibition of CNV; immunofluorecence and Western blot were used to detect the expression of VEGF in retina and choroid.Twentyeight days is the time point to determine the therapeutic efficacy. The expression of VEGF and the results of FFA were the sdandards of the judgement of therapeutic efficacy.Results Proliferaion of CNV to the retinal inner layer and the obvious leakage of fluoresein in the photocoagulation area indicated that the model of CNV was set up successfully. Twenty eight days after injection,obvious fluorescent leakage was found in the control group, and the average fluorescent leakage in bevacizumab group differed much from the control group（t=16.2952，Plt;0.05）; while the difference between ultrasonic microbubble + bevacizumb group and bevacizumab group was also significant (t=4.7955，Plt;0.05) . At the same time point, the expression of VEGF in bevacizumab group detected by immunofluorecent assay and Western blot differed much from the control group (t=7.0327，9.2596；Plt;0.05),and the difference of VEGF between ultrasonic microbubble + bevacizumb group and bevacizumab group was significant（t=2.9724,17.1937；Plt;0.05）. this experiment show that ultrasound combined bevacizumab intravitreal injection of the therapeutic effect of CNV superior to other groups(Plt;0.01).Conclusion Ultrasound microbubble combined with bevacizumab injection may improve the therapeutic effect on CNV by inhibiting the expression of VEGF.
Objective To observe the clinical efficacy of intravitreal Ranibizumab on exudative agerelated macular degeneration (AMD).Methods The clinical data of 46 patients（52 eyes）with exudative AMD were analyzed retrospectively. All patients were diagnosed by examination of early treatment of diabetic retinopathy study (ETDRS) charts, color fundus photograph，fluorescein angiography（FFA）or indocyanine green angiography（ICGA）and optical coherence tomography（OCT）.They received intravitreal injection of 0.05 ml (10 mg/ml) Ranibizumab, once per month for 3 months. Further injection may be required if the monthly followup indicated. A total of 52 eyes received 214 times of injections, each eye received 2-6 injections (mean 4.12). The Followup duration was 12 months. Vision acuity, fovea thickness and CNV leakage before and after treatment were analyzed.Results At the 12th month after treatment, the mean letter of ETDRS charts was 37.80 (11.40 letters more that pretreatment index,Plt;0.01). FFA and (or) ICGA showed complete closures choroidal neovascularization (CNV) in 11 eyes（21.20%），partial closures in 34 eyes (65.40%)，no change in four eyes (7.70%)，lesion growth in two eyes（3.80%）and new lesion in one eye (1.90%).OCT indicated the average of fovea thickness was 187.50 mu;m (122.80 mu;m less than the pretreatment index, Plt;0.01).Conclusion Intravitreal injection of Ranibizumab for exudative AMD according to this therapeutic schedule was well tolerated，with an improvement in visual acuity，FFA or ICGA and OCT.
The introduction of anti-vascular endothelial growth factor (VEGF) therapy represents a landmark in the management of wet age-related macular degeneration (AMD). However, as a new therapy, several problems such as durability of the therapeutic effects, medication side effects, and medication selection have emerged. We should make appoint of improving the therapeutic effect and safety by realizing the limitation of the therapy, monitoring the clinical potential adverse reactions of anti-VEGF agents, and recommending individualized treatment.
Anti-vascular dndothelial growth factor (VEGF) drugs have open up a new treatment channel for ocular neovascular diseases. A lots of clinical data has proved that anti-VEGF drugs are effective and safe. But we should also notice that long-term and excessive usage of anti-VEGF drugs brings some new problems and complications, and even affect the normal ocular physiological process of the angiogenesis and retinal blood flow. So, it is necessary to pay attention to the problems and potential risks of excessive usage of anti-VEGF therapies for ocular neovascular disease.