Intraocular pharmacokinetics of anti-vascular endothelial growth factor agents by intraoperative subretinal versus intravitreal injection in silicone oil-filled eyes of proliferative diabetic retinopathy: a randomized controlled pilot study

Systematic review of the efficacy and safety of stage I or II IOL implantation in patients with diabetic retinopathy

BACKGROUND

Intraocular lens (IOL) implantation is required after vitrectomy combined with cataract surgery in diabetic retinopathy patients. However, the question of whether an IOL should be implanted in stage I after vitrectomy or stage II during silicone oil filling has been controversial, and there has been no systematic review of this clinical issue.

METHODS

WanFang, SinoMed CNKI, VIP, PubMed, Embase, and Cochrane Library databases were systematically searched for relevant studies. The deadline was May 8, 2021. All studies of stage I or II IOL implantation in patients with diabetes who underwent vitrectomy were included. Revman 5.3 software was used for the meta-analysis.

RESULTS

Four studies, involving 253 eyes, were included. This study analyzed the literature with a common outcome index by meta-analysis and systematically evaluated the literature without a common outcome index. Four studies compared the efficacy and safety of the 2 sequential surgical methods in patients with diabetic retinopathy. The results of the meta-analysis showed that there was no significant difference in the efficacy and safety of stage II IOL implantation when compared with stage I IOL implantation (P > .05). One study showed that stage II cataract surgery with oil extraction resulted in better postoperative visual acuity and fewer complications than stage I cataract surgery with vitrectomy. One study showed that stage II IOL implantation during oil extraction had better postoperative visual acuity than stage I IOL implantation during vitrectomy without increasing surgical complications.

CONCLUSION

Vitrectomy combined with stage II IOL implantation is safer and more effective than stage I in patients with diabetic retinopathy; however, more clinical studies are needed to verify this.

Subretinal Injection Techniques for Retinal Disease: A Review

Inherited retinal dystrophies (IRDs) affect an estimated 1 in every 2000 people, this corresponding to nearly 2 million cases worldwide. Currently, 270 genes have been associated with IRDs, most of them altering the function of photoreceptors and retinal pigment epithelium. Gene therapy has been proposed as a potential tool for improving visual function in these patients. Clinical trials in animal models and humans have been successful in various types of IRDs. Recently, voretigene neparvovec (Luxturna^®) has been approved by the US Food and Drug Administration for the treatment of biallelic mutations in the RPE65 gene. The current state of the art in gene therapy involves the delivery of various types of viral vectors into the subretinal space to effectively transduce diseased photoreceptors and retinal pigment epithelium. For this, subretinal injection is becoming increasingly popular among researchers and clinicians. To date, several approaches for subretinal injection have been described in the scientific literature, all of them effective in accessing the subretinal space. The growth and development of gene therapy give rise to the need for a standardized procedure for subretinal injection that ensures the efficacy and safety of this new approach to drug delivery. The goal of this review is to offer an insight into the current subretinal injection techniques and understand the key factors in the success of this procedure.

Mesenchymal Stem Cell Exosomal miR-146a Mediates the Regulation of the TLR4/MyD88/NF-κB Signaling Pathway in Inflammation due to Diabetic Retinopathy

Diabetic retinopathy (DR) is the main cause of vision loss in diabetic patients, which cannot be completely resolved by typical blood sugar control. Inflammation influences the development of DR, so reducing the inflammatory response in DR patients is crucial to the prevention of DR. Therefore, we explored the regulatory effect of bone marrow mesenchymal stem cell (BMSC) exosomes on inflammation in DR mice. In order to analyze the mechanism of action, we used BMSC exosomal miR-146a to treat microglias in DR mice to observe cellular changes and expression of inflammatory factors. It was found that BMSC exosomal miR-146a reduced the levels of proliferating cell antigen and B-cell lymphoma-2 in microglias of DR mice and increased Bcl-2-related X with cysteine aspartic protease-3. By analyzing the expression of inflammatory factors, we found that BMSC exosomal miR-146a reduced the levels of TNF-α, IL-1β, and IL-6, which suggested that miR-146a can alleviate inflammation in DR mice. Further exploration found that miR-146a reduced the activity of TLR4 and increased the activity of MyD88 and NF-κB. Furthermore, the overexpression of TLR4 reversed the effects of miR-146a on the proliferation, apoptosis, and inflammation of microglias. Our study demonstrated that BMSC exosomal miR-146a can regulate the inflammatory response of DR by mediating the TLR4/MyD88/NF-κB pathway, providing an experimental basis for the prevention and treatment of DR.