Table 2 Summary of potential treatments for diabetic retinopathy (DR)

Neurotrophic factors

PEDF

• Neuroprotection

• Anti-oxidative stress

• Anti-inflammation

• Anti-angiogenesis

• Reduction of blood glucose, glutamate excitotoxicity, iNOS level

[120, 125, 129]

BDNF

[121, 130, 131]

Insulin & IGF-1

[122, 134, 138]

SST

[123, 139]

GLP-1

[124, 143, 146,147,148]

Anti-oxidants

Flavonoids (Quercetin, Curcumin)

• Anti-oxidative stress

• Anti-inflammation

• Anti-angiogenesis

• Decrease of retinal neurons apoptosis

[153,154,155,156,157,158]

Carotenoids (Lutein, Zeaxanthin)

[160,161,162,163,164]

Anti- inflammation agents

TNFα antagonist (Etanercept, Adalimumab, Infliximab)

• Decrease of retinal neurons, pericytes and endothelial cells loss

• Reduction of inflammatory cytokines level

• Inhibition of glial activation and PARP-1

[165,166,167]

SOCS 1

[170, 171]

Tetracycline derivatives (Minocycline, Doxycycline)

[172,173,174,175]

Cell replacement

MSC

• Anti-oxidative stress

• Anti-inflammation

• Decrease of retinal neurons, pericytes and endothelial cells loss

• Increase of neurotrophic factors

• Differentiation into retinal and vascular cells

[178,179,180,181]

EPC

[184,185,186]

HSC

[187]

iPSC

[188, 189]

Other treatments

Inhibition of iNOS (iNOS knockout Aminoguanidine, Sesamin)

• Decrease of retinal neurons, pericytes and endothelial cells loss

• Anti-inflammation

• Reduction of blood glucose

[195,196,197,198,199]

L-DOPA

• Preservation of retinal functions

[200,201,202]

ET-1 receptor antagonist (Atrasentan, bosentan )

• Decrease of retinal neurons, pericytes and endothelial cells loss

• Inhibition of glial activation

• Neuroprotection

[204,205,206]