Postbiotics: emerging therapeutic approach in diabetic retinopathy.

Diabetic retinopathy (DR) is a prevalent microvascular complication in diabetic patients that poses a serious risk as it can cause substantial visual impairment and even vision loss. Due to the prolonged onset of DR, lengthy treatment duration, and limited therapeutic effectiveness, it is extremely important to find a new strategy for the treatment of DR. Postbiotic is an emerging dietary supplement which consists of the inactivate microbiota and its metabolites. Numerous animal experiments have demonstrated that intervention with postbiotics reduces hyperglycemia, attenuates retinal peripapillary and endothelial cell damage, improves retinal microcirculatory dysfunction, and consequently delays the progression of DR. More strikingly, unlike conventional probiotics and prebiotics, postbiotics with small molecules can directly colonize the intestinal epithelial cells, and exert heat-resistant, acid-resistant, and durable for storage. Despite few clinical significance, oral administration with postbiotics might become the effective management for the prevention and treatment of DR. In this review, we summarized the basic conception, classification, molecular mechanisms, and the advances in the therapeutic implications of postbiotics in the pathogenesis of DR. Postbiotics present great potential as a viable adjunctive therapy for DR.

COMPARISON OF PROJECTION-RESOLVED OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY-BASED METRICS FOR THE EARLY DETECTION OF RETINAL MICROVASCULAR IMPAIRMENTS IN DIABETES MELLITUS.

PURPOSE: To determine the ability of nonperfusion, vessel density, and morphologic measurements using projection-resolved optical coherence tomography angiography to detect early retinal microvasculature impairments in diabetes mellitus. METHODS: A retrospective review was performed on Type 2 diabetes mellitus patients with no diabetic retinopathy (DR) or mild nonproliferative DR and age-matched controls imaged with optical coherence tomography angiography. Foveal avascular zone-related metrics and extrafoveal avascular area were measured in optical coherence tomography angiography images. Vessel density and fractal dimension were calculated with and without a skeletonization process. The vessel diameter index and vessel tortuosity were computed. The area under the receiver operating characteristic curve (AUC) estimated diagnostic performances. RESULTS: Dilated capillary diameter was observed in the deep capillary plexus in the diabetic groups. Vessel density and fractal dimension of skeletonized deep capillary plexus significantly and progressively decreased in the no DR and mild nonproliferative DR groups compared with controls. Superficial extrafoveal avascular area, vessel density, and fractal dimension of the skeletonized deep capillary plexus had the highest diagnostic performance to differentiate mild nonproliferative DR from control eyes, with AUCs of 0.885, 0.876, and 0.876, respectively. CONCLUSION: Vessel density and fractal dimension from the skeletonized deep capillary network may be the most sensitive for detecting early retinal capillary loss in diabetes mellitus.

Comparison of outcomes between overlapping-spot and single-spot photodynamic therapy for circumscribed choroidal hemangioma.

AIM: To compare the efficacy and safety of photodynamic therapy (PDT) with overlapping multiple spots and single spot for treating circumscribed choroidal hemangioma. METHODS: Twenty-two patients (22 eyes) with symptomatic circumscribed choroidal hemangioma received PDT treatment. Fourteen patients received overlapping spots (two to three spots) PDT, whereas eight patients received single-spot PDT. Laser was used at 50J/cm(2) for 83s in the overlapping-spot group and 50J/cm(2) for 166s in the single-spot group. Clinical examination, funduscopy, fluorescein angiography, and ultrasonography were performed at baseline and after treatment. RESULTS: The mean follow-up time was 28.5±8.0 months in the overlapping-spot group and 27.0±5.0 months in the single-spot group. Nine patients (64.2%) had their vision improved over two lines on the Snellen chart, and five patients showed stable visual acuity in the overlapping-spot group. The mean thickness of tumor decreased from 2.7±0.8mm to 1.2±0.9mm, and the mean greatest tumor linear dimension decreased from 7.4±1.5mm to 4.5±3.5mm after treatment. In the single-spot group, two patients (25%) had their vision improved over two lines on the Snellen chart, and six patients had unchanged stable vision. The mean tumor thickness in this group decreased from 2.5±0.7mm to 1.4±1.0mm, and the mean greatest tumor linear dimension decreased from 7.2±1.3mm to 4.7±3.6mm. No significant differences in visual improvement and tumor regression were found between the two groups. CONCLUSION: Overlapping-spot PDT under appropriate treatment parameters and strategies is as effective and safe as single-spot PDT for treating symptomatic circumscribed choroidal hemangioma. Improved or stabilized visual acuity was achieved as a result of tumor regression.

[Adverse reactions during fluorescence fundus angiography in special patients].

OBJECTIVE: To determine the incidence rate and correlation factors of the adverse reactions during fluorescence fundus angiography (FFA) in special patients. METHODS: 256 special patients were performed FFA with Heidelberg Retinal Angiography. Fluorescein Sodium was given according to the body weight and adverse reactions during FFA were observed. The special patients enrolled in this study include those with drug allergy history, system disease, light adverse reactions such as nausea, vomiting and pruritus during the fist FFA or patients over 80 years old. RESULTS: Adverse reactions were observed in 69 of 256 (27.0%) cases and the majority is at a mild to moderate degree. Nausea, sneezing, vomiting or pruritus occurred in 10 of 73 (13.7%) patients with drug allergy history. Nausea or vomiting occurred in 4 of 78 (5.1%) patients with systemic diseases. Different degrees of adverse reactions occurred in 54 of 56 (94.6%) cases who had nausea, vomiting or pruritus during the first FFA. Nausea occurred in 1 of 49 (2.0%) patients over 80 years old. CONCLUSION: FFA is a safe examination for the above special patients. The incidence rate of adverse reaction due to FFA in these special patients is similar to that in the healthy population. Observing the patients closely and strengthening the containment and salvage measures are important to improve the safety of FFA in these special patients.

[Combination facula photodynamic therapy for circumscribed choroidal hemangioma].

OBJECTIVE: To assess the clinical effect of combination facula photodynamic therapy (PDT) on patients with circumscribed choroidal hemangioma. METHODS: It was a retrospective case series. Ten cases of circumscribed choroidal hemangioma were diagnosed by ophthalmoscopy, fundus fluorescein angiography and B-scanning ultrasound examination. Clinical data of these cases were retrospectively analyzed. All of these patients had undergone combination facula PDT. The best corrected visual acuity before PDT was FC to 0.3. The maximum diameter of the tumor was 5.5-9.9 mm and averaged 6-8 mm. The maximum thickness of the tumor was 1.1-3.8 mm and averaged 2.7 mm. Four patients suffered from retinal detachment The intravenous injection of visudyne (6 mg/m2) was performed in 10 minutes. Five minutes later, laser irradiation (wave length 689 nm) was performed with the parameters of 50 J/cm2, 83 s, and 2 to 3 spots. The follow-up period was 3.0 to 15.0 months (mean 8.5 months). RESULTS: The visual acuity in the last examination after treatment was FC-1.0, which was 2-line increased in 7 patients and was steady in 3 patients. B-scanning ultrasound examination showed that the hemangioma was undetectable in 2 patients, and in the other 8 patients,the hemangioma had the diameter of 4.2 to 8.3 mm (average 6.4 mm) and the thickness was 0.5 to 2.7 mm (average 1.9 mm). Retina detachment disappeared in 2 patients CONCLUSIONS: Combination facula PDT may lead to the shrinking of choroidal hemangioma, disappearance of subretinal fluid, reattachment of retina and the increase or saving of the visual acuity. It is a effective and safe treatment for the macular circumscribed choroidal hemangioma.

[Evaluation of photodynamic therapy in idiopathic choroidal neovascularization].

OBJECTIVE: To evaluate the effectiveness of photodynamic therapy (PDT) in the treatment of idiopathic choroidal neovascularization (CNV). METHODS: Sixty-one cases (61 eyes) of CNV were treated with PDT and the fundus appearance, visual acuity, retina thickness as well as the fundus angiographic imaging were observed before and after the therapy. PDT was performed 1.2 times in average and the follow-up period was 6 - 36 months (mean 19 months). RESULTS: At the last follow up, the visual acuity was improved in 41 eyes (67.2%), unchanged in 15 eyes (24.6%) and slightly decreased in 5 eyes (8.2%). Macular hemorrhage and exudation reduced in all cases after PDT. Fundus angiography showed complete closure of CNV in 38 eyes (62.3%), partial closure in 4 eyes (6.6%), incomplete closure in 14 eyes (23.0%) and recurrence in 5 eyes (8.2%). In 6 eyes CNV was complete closed after single PDT with diminish of macular edema and neuronal retinal epithelial detachment. No recurrent CNV was observed during three years' follow-up and the visual acuity remained stable. Our results also demonstrated that the therapeutic effect decreased with patient's age (t = 0.476, P = 0.016). The decrease of visual acuity averaged 0.008 per year. CONCLUSION: Photodynamic therapy is a potential treatment for idiopathic CNV and better outcomes are achieved in younger patients.

[Indocyanine green and fluorescein angiography study of glaucomatous peripapillary atrophy].

OBJECTIVE: To investigate the incidence of glaucomatous peripapillary atrophy (PPA) and choroidal circulation of glaucomatous patients. METHODS: The subjects of glaucoma groups included 43 (43 eyes) glaucomatous patients including 16 (16 eyes) chronic angle-closure glaucoma (CACG), 27 (27 eyes) open-angle glaucoma. Control group included 33 (33 eyes) cases. Indocyanine green angiography and fundus fluorescein angiography were performed on glaucoma groups and control group with Heidelberg retinal angiography (HRA) to observe alpha zone and beta zone of PPA. RESULTS: The frequency of beta zone in CACG, open-angle glaucoma and control group was 31.3%, 77.8% and 21.9%, respectively, with statistically significant difference between these groups (chi(2) = 19.915, P = 0.000). Beta zone showed ICG hypofluorescence in all eyes. There were no statistically significant difference in the frequency of alpha zone between glaucoma groups and control group. However, there were two different types of indocyanine green filling in alpha zone: normal or decreased choroid filling. Decreased choroid filling in alpha zone was observed in 53.8% of eyes with chronic angle-closure glaucoma, 66.7% of open-angle glaucoma and 32.1% of in control, the difference was significant (chi(2) = 6.648, P = 0.036). CONCLUSIONS: The frequency of zone beta with no choroidal filling in open-angle glaucoma group is the highest among these three groups. Zone alpha in glaucomatous eyes show decreased choroidal circulation, which may be the early sign for the extension of beta zone.