Autophagy activation and the mechanism of retinal microvascular endothelial cells in hypoxia

AIM： To explore the state of autophagy and related mechanisms in the murine retinal microvascular endothelial cells（RMECs） under hypoxia stimulation.METHODS： The murine RMECs were primarily cultured and randomly divided into three groups： hypoxia group（cultured in 1% O_2 environment）, hypoxia＋autophagy inhibition group [pretreated with 5 mmol/L 3-methyladenine（3-MA） for 4 h followed by incubation in 1% O_2] and control group（cultured under normoxic condition）. The state of autophagy in RMECs was examined by assaying the turnover of light chain 3 B（LC3BB） and expression of Beclin-1, Atg3 and Atg5 proteins with Western blotting, by detecting formation of autophagosomes with transmission electron microscopy（TEM） and by counting the number of GFP＋ puncta in RMECs. The protein levels of AMPK, P-AMPK, Akt, P-Akt, m-TOR and P-m TOR were also assayed by Western blotting.RESULTS： Primary murine RMECs were successfully cultured. Under hypoxic conditions, the ratio of LC3BB-Ⅱ/Ⅰ and the expression of Beclin-1, Atg3 and Atg5 proteins were increased when compared with the control group. In addition, the numbers of autophagosome and the GFP＋ puncta were also increased under hypoxia. However, pretreatment with 3-MA obviously attenuated these changes in autophagy in RMECs under hypoxia. Protein expression of P-Akt and P-AMPK was increased but P-m TOR level was decreased in cells exposed to hypoxia. CONCLUSION： In murine RMECs autophagy is activated under hypoxia possibly through activation of the AMPK/mTOR signaling pathway.

Neovascular Glaucoma: An Update on Etiopathogenesis, Diagnostics and Management

Neovascular glaucoma (NVG) is a severe secondary and refractory *severe secondary conditio, that accounts for a varying prevalence between 0.01% to 5.1% of all glaucoma those studied in different regions of the world. **This is a pathological condition, which is caused by the new vessels over iris surface and followed by fibrovascular membrane formation over the trabecular meshwork, secondary to a local angiogenic stimulus. The fibrovascular membrane over trabecular meshwork obstructs the aqueous outflow at an angle of the anterior chamber. ***The obstruction in outflow of the aqueous results increase of intraocular pressure (IOP), within the eyeball. NVG results from a number of ocular and systemic conditions with retinal ischemia leading to anoxia as a mediator in over 95% of cases. Most of them are affected with proliferative diabetic retinopathy (PDR) followed by central retinal venous occlusion (CRVO), and ocular ischemic syndrome (OIS) along with other uncommon causes or all those causes that causes retinal anoxia which led to angiogenic activity in retina and iris of eye. Although NVG overall prevalence is low, but it is a dreadful condition led to blindness. The objective of this review is to provide detailed information on its basic and clinical aspects, to enable us to manage it logically. Here its etiopathogenesis, methods of early diagnosis and management are discussed. It was concluded that if NVG is detected earlier and managed systematically (both medical and surgical) along with an eye on alleviation of different aggravating factors of the retinal hypoxia, it could be a sight-saving measure to the affected person.