Diabetic retinopathy (DR) frequently results in compromised visual function, with hyperglycemia-induced disruption of the blood-retinal barrier (BRB) through various pathways as a critical mechanism. Existing DR treatments fail to address early and potentially reversible microvascular alterations. This study examined the effects of empagliflozin (EMPA), a selective Sodium-glucose transporter 2 (SGLT2) inhibitor, on the retina of db/db mice. The objective of this study is to investigate the potential role of EMPA in the prevention and delay of DR.
Methods
db/db mice were randomly assigned to either the EMPA treatment group (db/db + Emp) or the model group (db/db), while C57 mice served as the normal control group (C57). Mice in the db/db + Emp group received EMPA for eight weeks. Body weight, fasting blood glucose (FBG), and blood VEGF were subsequently measured in all mice, along with the detection of specific inflammatory factors and BRB proteins in the retina. Retinal SGLT2 protein expression was compared using immunohistochemical analysis, and BRB structural changes were observed via electron microscopy.
Results
EMPA reduced FBG, blood VEGF, and retinal inflammatory factors TNF-α, IL-6, and VEGF levels in the eye tissues of db/db mice. EMPA also increased Claudin-1, Occludin-1, and ZO-1 levels while decreasing ICAM-1 and Fibronectin, thereby preserving BRB function in db/db mice. Immunohistochemistry revealed that EMPA reduced SGLT2 expression in the retina of diabetic mice, and electron microscopy demonstrated that EMPA diminished tight junction damage between retinal vascular endothelial cells and prevented retinal vascular basement membrane thickening in diabetic mice.
Conclusion
EMPA mitigates inflammation and preserves BRB structure and function, suggesting that it may prevent DR or serve as an effective early treatment for DR.
ZhengYHeMCongdonN. The worldwide epidemic of diabetic retinopathy. Indian J Ophthalmol2012; 60(5): 428–431.
2.
TakkarBDasTThamarangsiT, et al.Development of diabetic retinopathy screening guidelines in South-East Asia region using the context, challenges, and future technology. Semin Ophthalmol2022; 37(1): 97–104.
3.
DasAStroudSMehtaA, et al.New treatments of diabetic retinopathy. Diabetes Obes Metab2015; 17(3): 219–230.
4.
WangWLoACY. Diabetic retinopathy: pathophysiology and treatments. Int J Mol Sci2018; 19(6): 1816.
5.
WakisakaMNagaoT. Sodium glucose cotransporter 2 in mesangial cells and retinal pericytes and its implications for diabetic nephropathy and retinopathy. Glycobiology2017; 27(8): 691–695.
6.
ZaghloulMSElshalMAbdelmageedME. Preventive empagliflozin activity on acute acetic acid-induced ulcerative colitis in rats via modulation of SIRT-1/PI3K/AKT pathway and improving colon barrier. Environ Toxicol Pharmacol2022; 91: 103833.
7.
AminEFRifaaiRAAbdel-LatifRG. Empagliflozin attenuates transient cerebral ischemia/reperfusion injury in hyperglycemic rats via repressing oxidative-inflammatory-apoptotic pathway. Fundam Clin Pharmacol2020; 34(5): 548–558.
8.
LahnwongSChattipakornSCChattipakornN. Potential mechanisms responsible for cardioprotective effects of sodium-glucose co-transporter 2 inhibitors. Cardiovasc Diabetol2018; 17(1): 101.
9.
YaribeygiHButlerAEAtkinSL, et al.Sodium-glucose cotransporter 2 inhibitors and inflammation in chronic kidney disease: possible molecular pathways. J Cell Physiol2018; 234(1): 223–230.
10.
WakisakaM. Empagliflozin and progression of kidney disease in type 2 diabetes. N Engl J Med2016; 375(18): 1799–1800.
11.
KosiborodMCavenderMAFuAZ, et al.Lower risk of heart failure and death in patients initiated on sodium-glucose cotransporter-2 inhibitors versus other glucose-lowering drugs: the CVD-REAL study (comparative effectiveness of cardiovascular outcomes in new users of sodium-glucose cotransporter-2 inhibitors). Circulation2017; 136(3): 249–259.
12.
WakisakaMYoshinariMNakamuraS, et al.Suppression of sodium-dependent glucose uptake by captopril improves high-glucose-induced morphological and functional changes of cultured bovine retinal pericytes. Microvasc Res1999; 58(3): 215–223.
13.
KalraS. Sodium glucose co-transporter-2 (SGLT2) inhibitors: a review of their basic and clinical pharmacology. Diabetes Ther2014; 5(2): 355–366.
14.
LahotiSNashawiMSheikhO, et al.Sodium-glucose co-transporter 2 inhibitors and diabetic retinopathy: insights into preservation of sight and looking beyond. Cardiovasc Endocrinol Metab2021; 10(1): 3–13.
15.
MatthewsJHeratLRooneyJ, et al.Determining the role of SGLT2 inhibition with Empagliflozin in the development of diabetic retinopathy. Biosci Rep2022; 42(3): BSR20212209.
16.
FujiwaraAKanzakiYKimuraS, et al.En face image-based classification of diabetic macular edema using swept source optical coherence tomography. Sci Rep2021; 11(1): 7665.
17.
TakatsunaYIshibashiRTatsumiT, et al.Sodium-Glucose cotransporter 2 inhibitors improve chronic diabetic macular edema. Case Rep Ophthalmol Med2020; 2020: 8867079.
18.
TatsumiTOshitariTTakatsunaY, et al.Sodium-Glucose co-transporter 2 inhibitors reduce macular edema in patients with diabetes mellitus. Life (Basel)2022; 12(5): 692.
19.
HanaguriJYokotaHKushiyamaA, et al.The effect of sodium-dependent glucose cotransporter 2 inhibitor tofogliflozin on neurovascular coupling in the retina in type 2 diabetic mice. Int J Mol Sci2022; 23(3): 1422–0067.
20.
HeratLYMatthewsJROngWE, et al.Determining the role of SGLT2 inhibition with dapagliflozin in the development of diabetic retinopathy. Front Biosci (Landmark Ed)2022; 27(12): 321.
21.
ZahraouiALouvardDGalliT. Tight junction, a platform for trafficking and signaling protein complexes. J Cell Biol2000; 151(5): F31–F36.
22.
FörsterC. Tight junctions and the modulation of barrier function in disease. Histochem Cell Biol2008; 130(1): 55–70.
23.
HaseloffRFDithmerSWinklerL, et al.Transmembrane proteins of the tight junctions at the blood-brain barrier: structural and functional aspects. Semin Cell Dev Biol2015; 38: 16–25.
24.
KlaassenIVan NoordenCJSchlingemannRO. Molecular basis of the inner blood-retinal barrier and its breakdown in diabetic macular edema and other pathological conditions. Prog Retin Eye Res2013; 34: 19–48.
25.
TentolourisAEleftheriadouITzeraviniE, et al.Endothelium as a therapeutic target in diabetes Mellitus: from basic mechanisms to clinical practice. Curr Med Chem2020; 27(7): 1089–1131.
26.
TaharaATakasuTYokonoM, et al.Characterization and comparison of SGLT2 inhibitors: part 3. Effects on diabetic complications in type 2 diabetic mice. Eur J Pharmacol2017; 809: 163–171.
27.
SabanerMCDumanRDoganM, et al.Do SGLT2 inhibitors prevent preclinical diabetic retinopathy? A prospective pilot optical coherence tomography angiography study. J Fr Ophtalmol2021; 44(8): 1159–1167.
28.
WaiKMSarojNBoucherN, et al.Evaluating the effect of hypoglycemic agents on diabetic retinopathy progression. Ophthalmic Surg Lasers Imaging Retina2023; 54(3): 158–165.
29.
RoySBaeEAminS, et al.Extracellular matrix, gap junctions, and retinal vascular homeostasis in diabetic retinopathy. Exp Eye Res2015; 133: 58–68.
30.
LenselinkEA. Role of fibronectin in normal wound healing. Int Wound J2015; 12(3): 313–316.
31.
RoySNasserSYeeM, et al.A long-term siRNA strategy regulates fibronectin overexpression and improves vascular lesions in retinas of diabetic rats. Mol Vis2011; 17: 3166–3174. PMID： 22171163.
32.
OshitariTPolewskiPChaddaM, et al.Effect of combined antisense oligonucleotides against high-glucose- and diabetes-induced overexpression of extracellular matrix components and increased vascular permeability. Diabetes2006; 55(1): 86–92.
33.
SaadRTadmorHErtrachtO, et al.The molecular effects of SGLT2i empagliflozin on the autophagy pathway in diabetes Mellitus type 2 and its complications. J Diabetes Res2022; 2022: 8337823.
34.
AbbasNATEl SalemAAwadMM. Empagliflozin, SGLT(2) inhibitor, attenuates renal fibrosis in rats exposed to unilateral ureteric obstruction: potential role of klotho expression. Naunyn Schmiedebergs Arch Pharmacol2018; 391(12): 1347–1360.
35.
MohammadGMairaj SiddiqueiMImtiaz NawazM, et al.The ERK1/2 inhibitor U0126 attenuates diabetes-induced upregulation of MMP-9 and biomarkers of inflammation in the retina. J Diabetes Res2013; 2013: 658548.
36.
SimóRSundstromJMAntonettiDA. Ocular anti-VEGF therapy for diabetic retinopathy: the role of VEGF in the pathogenesis of diabetic retinopathy. Diabetes Care2014; 37(4): 893–899.
BehlYKrothapalliPDestaT, et al.Diabetes enhanced tumor necrosis factor-alpha production promotes apoptosis and the loss of retinal microvascular cells in type 1 and type 2 models of diabetic retinopathy. Am J Pathol2008; 172(5): 1411–1418.
39.
HuangHGandhiJKZhongX, et al.TNFalpha is required for late BRB breakdown in diabetic retinopathy, and its inhibition prevents leukostasis and protects vessels and neurons from apoptosis. Invest Ophthalmol Vis Sci2011; 52(3): 1336–1344.
40.
CohenTNahariDCeremLW, et al.Interleukin 6 induces the expression of vascular endothelial growth factor. J Biol Chem1996; 271(2): 736–741.
41.
MaruoNMoritaIShiraoM, et al.IL-6 increases endothelial permeability in vitro. Endocrinology1992; 131(2): 710–714.
42.
ScisciolaLCataldoVTaktazF, et al.Anti-inflammatory role of SGLT2 inhibitors as part of their anti-atherosclerotic activity: data from basic science and clinical trials. Front Cardiovasc Med2022; 9: 1008922.
43.
OelzeMKröller-SchönSWelschofP, et al.The sodium-glucose co-transporter 2 inhibitor empagliflozin improves diabetes-induced vascular dysfunction in the streptozotocin diabetes rat model by interfering with oxidative stress and glucotoxicity. PLoS One2014; 9(11): e112394.
44.
GanbaatarBFukudaDShinoharaM, et al.Empagliflozin ameliorates endothelial dysfunction and suppresses atherogenesis in diabetic apolipoprotein E-deficient mice. Eur J Pharmacol2020; 875: 173040.
