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 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.

[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.