Anti-inflammatory effect of glucagon-like Peptide-1 receptor agonist on the neurosensory retina in an acute optic nerve injury rat model.

PURPOSE: To explore the possibility of using glucagon-like peptide-1 receptor agonist (GLP-1RA) as a new treatment for neuroinflammation, by analyzing retinal pathological changes in an optic nerve crush rat model. METHODS: Eight-week-old male Sprague-Dawley rats were divided into lixisenatide (LIX, n = 10), traumatic control (T-CON, n = 10), and normal control (n = 5) groups. The optic nerves of left eyes in the LIX and T-CON groups were crushed in a standardized manner. The LIX group was treated with subcutaneous injections of lixisenatide (200 µg/kg/day) for 5 days. One week after initiating treatment, quantitative polymerase chain reaction, Western blot, and immunohistochemistry analyses were performed on the retinal tissues of each group to identify inflammatory markers. RESULTS: The LIX group showed significantly lower mRNA levels of interleukin 1 beta (IL-1ß), tumor necrosis factor-alpha (TNF-α), thioredoxin interacting protein (TXNIP), and glial fibrillary acidic protein (GFAP) than the T-CON group. Also, the LIX group exhibited decreased TXNIP and GFAP expression compared with the T-CON group, and similar expression to the normal control group, according to Western blot analysis. Significantly increased immunohistochemistry staining of Brn3a and decreased TUNEL staining were seen in the LIX group compared with the T-CON group, indicating that lixisenatide contributes to retinal ganglion cell survival in cases of acute optic nerve injury. CONCLUSIONS: Neuroinflammation was significantly reduced in lixisenatide-treated retinas compared with untreated retinas in our acute optic nerve injury rat model. The neuroprotective effect of lixisenatide indicates that it can serve a new treatment option against clinically intractable traumatic optic neuropathy.

Association between the use of allopurinol and risk of increased thyroid-stimulating hormone level.

Allopurinol is the first-line agent for patients with gout, including those with moderate-to-severe chronic kidney disease. However, increased thyroid-stimulating hormone (TSH) levels are observed in patients with long-term allopurinol treatment. This large-scale, nested case-control, retrospective observational study analysed the association between allopurinol use and increased TSH levels. A common data model based on an electronic medical record database of 19,200,973 patients from seven hospitals between January 1997 and September 2020 was used. Individuals aged > 19 years in South Korea with at least one record of a blood TSH test were included. Data of 59,307 cases with TSH levels > 4.5 mIU/L and 236,508 controls matched for sex, age (± 5), and cohort registration date (± 30 days) were analysed. An association between the risk of increased TSH and allopurinol use in participants from five hospitals was observed. A meta-analysis (I2 = 0) showed that the OR was 1.51 (95% confidence interval: 1.32-1.72) in both the fixed and random effects models. The allopurinol intake group demonstrated that increased TSH did not significantly affect free thyroxine and thyroxine levels. After the index date, some diseases were likely to occur in patients with subclinical hypothyroidism and hypothyroidism. Allopurinol administration may induce subclinical hypothyroidism.

The Anti-Inflammatory Effects of Glucagon-Like Peptide Receptor Agonist Lixisenatide on the Retinal Nuclear and Nerve Fiber Layers in an Animal Model of Early Type 2 Diabetes.

This study explored the anti-inflammatory effects of a glucagon-like peptide-1 receptor agonist (GLP-1RA), known as lixisenatide, on the eyes of early type 2 diabetic mice. Diabetic (db/db) mice were divided into three groups: GLP-1RA [lixisenatide (LIX)], insulin (INS) with controlled hyperglycemia based on the glucose concentration of lixisenatide, and diabetic control (D-CON). Nondiabetic control mice (db/dm) were also characterized for comparison. After 8 weeks of treatment, mRNA levels of inflammatory markers, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, immunohistochemical staining; Western blot of glial fibrillary acidic protein (GFAP) and thioredoxin-interacting protein; and retinal thickness were assessed in the central and peripheral neurosensory retina. LIX showed decreased immunohistochemical staining for both thioredoxin-interacting protein and GFAP in the central and peripheral neurosensory retina compared with D-CON and INS, and decreased expression of these proteins in the neurosensory retina and immunohistochemical staining in the optic nerve head for GFAP compared with D-CON. The inner nuclear layer in the peripheral retina in LIX was only thinner than those of D-CON and INS. In an early type 2 diabetic mouse model, lixisenatide treatment showed superior anti-inflammatory effects on the retina and optic nerve head independent of hyperglycemia. Thus, the neuroprotective effects of lixisenatide treatment in the peripheral inner nuclear layer should be evaluated in early type 2 diabetic retinopathy.

Surgical and sensory outcomes in patients with intermittent exotropia according to preoperative refractive error.

BACKGROUND/OBJECTIVES: To analyze the surgical and sensory outcomes of intermittent exotropia according to refractive errors and the factors associated with surgical success. SUBJECTS/METHODS: A total of 326 children were divided into three groups according to preoperative refractive error; hyperopic eyes with SE ≥+2D (hyperopic group), eyes with SE between -1D and +2D (emmetropic group), and myopic eyes with SE ≤-1D (myopic group). The surgical outcomes and the sensory outcomes measured by near and distant stereoacuity were compared among the three groups. RESULTS: The surgical success rate in hyperopic group was significantly lower compared to myopic group at last follow-up (P = 0.012). Preoperative near stereopsis was not different among three groups, however, the distance stereopsis was significantly deteriorated in the hyperopic group compared to the other two groups (Titmus; P = 0.168, FD2; P < 0.001, DR; P = 0.048). There was postoperative improvement in both near and distant stereopsis in all three groups (Titmus; P = 0.009, FD2; P = 0.021, DR; P = 0.036) and no significant difference was found in the postoperative distant stereopsis among the three groups. CONCLUSIONS: Preoperative refractive error is a prognostic factor of surgical success in patients with intermittent exotropia. Patients with hyperopia achieved less favorable surgical outcome compared to myopic patients. The preoperative distant stereoacuity was decreased in hyperopic patients compared to myopic patients, which eventually improved after surgery and showed no significant difference at postoperative measurements.

Effect of trapping vascular endothelial growth factor-A in a murine model of dry eye with inflammatory neovascularization.

AIM: To evaluate whether trapping vascular endothelial growth factor A (VEGF-A) would suppress angiogenesis and inflammation in dry eye corneas in a murine corneal suture model. METHODS: We established two groups of animals, one with non-dry eyes and the other with induced dry eyes. In both groups, a corneal suture model was used to induce inflammation and neovascularization. Each of two groups was again divided into three subgroups according to the treatment; subgroup I (aflibercept), subgroup II (dexamethasone) and subgroup III (phosphate buffered saline, PBS). Corneas were harvested and immunohistochemical staining was performed to compare the extents of neovascularization and CD11b+ cell infiltration. Real-time polymerase chain reaction was performed to quantify the expression of inflammatory cytokines and VEGF-A in the corneas. RESULTS: Trapping VEGF-A with aflibercept resulted in significantly decreased angiogenesis and inflammation compared with the dexamethasone and PBS treatments in the dry eye corneas (all P<0.05), but with no such effects in non-dry eyes. The anti-inflammatory and anti-angiogenic effects of VEGF-A trapping were stronger than those of dexamethasone in both dry eye and non-dry eye corneas (all P<0.05). The levels of RNA expression of VEGF-A, TNF-alpha, and IL-6 in the aflibercept subgroup were significantly decreased compared with those in the PBS subgroup in the dry eye group. CONCLUSION: Compared with non-dry eye corneas, dry eye corneas have greater amounts of inflammation and neovascularization and also have a more robust response to anti-inflammatory and anti-angiogenic agents after ocular surface surgery. Trapping VEGF-A is effective in decreasing both angiogenesis and inflammation in dry eye corneas after ocular surface surgery.

Comparison of postoperative corneal changes between dry eye and non-dry eye in a murine cataract surgery model.

AIM: To compare the effects of the surgical insult of cataract surgery on corneal inflammatory infiltration, neovascularization (NV) and lymphangiogenesis (LY) between the dry eye and non-dry eye in murine cataract surgery models. METHODS: We established two groups of animals, one with normal eyes (non-dry eye) and the second with induced dry eyes. In both groups, we used surgical insults to mimic human cataract surgery, which consisted of lens extraction, corneal incision and suture. After harvesting of corneas on the 9(th) postoperative day and immunohistochemical staining, we compared NV, LY and CD11b+ cell infiltration in the corneas. RESULTS: Dry eye group had significantly more inflammatory infiltration (21.75%±7.17% vs 3.65%±1.49%; P=0.049). The dry eye group showed significantly more NV (48.21%±4.02% vs 26.24%±6.01%; P=0.016) and greater levels of LY (9.27%±0.48% vs 4.84%±1.15%; P=0.007). In corneas on which no surgery was performed, there was no induction of NV in both the dry and non-dry group, but dry eye group demonstrated more CD11b+ cells infiltration than the non-dry eye group (0.360%±0.160% vs 0.023%±0.006%; P=0.068). Dry eye group showed more NV than non-dry eye group in both topical PBS application and subconjunctival PBS injection (P=0.020 and 0.000, respectively). CONCLUSION: In a murine cataract surgery model, preexisting dry eye can induce more postoperative NV, LY, and inflammation in corneal tissue.

The effect of topical cyclosporine 0.05% on dry eye after cataract surgery.

PURPOSE: To evaluate the effectiveness of cyclosporine 0.05% for dry eye after cataract surgery. METHODS: Thirty-two newly diagnosed patients with dry eye syndrome 1 week after cataract surgery received a twice-daily treatment of cyclosporine 0.05% for one eye and normal saline 0.9% for the other. Disease severity was measured at 2 weeks, 1 month, 2 months, and 3 months by Schirmer test I (ST-I), tear film break-up time (tBUT), corneal temperature and dry eye symptom questionnaire (Ocular Surface Disease Index). RESULTS: Both groups increased in ST-I and tBUT over time. ST-I in the cyclosporine 0.05% group showed a significant increase at 3 months and tBUT in the cyclosporine 0.05% group showed an increase at 2 and 3 months. The dry eye symptom score was significantly reduced in the cyclosporine 0.05% group. CONCLUSIONS: Cyclosporine 0.05% can also be an effective treatment for dry eye after cataract surgery.