Retinal astrocytes and microglia activation in diabetic retinopathy rhesus monkey models

Dysregulated CD200-CD200R signaling in early diabetes modulates microglia-mediated retinopathy

Diabetic retinopathy (DR) is a neurovascular complication of diabetes. Recent investigations have suggested that early degeneration of the neuroretina may occur prior to the appearance of microvascular changes; however, the mechanisms underlying this neurodegeneration have been elusive. Microglia are the predominant resident immune cell in the retina and adopt dynamic roles in disease. Here, we show that ablation of retinal microglia ameliorates visual dysfunction and neurodegeneration in a type I diabetes mouse model. We also provide evidence of enhanced microglial contact and engulfment of amacrine cells, ultrastructural modifications, and transcriptome changes that drive inflammation and phagocytosis. We show that CD200-CD200R signaling between amacrine cells and microglia is dysregulated during early DR and that targeting CD200R can attenuate high glucose-induced inflammation and phagocytosis in cultured microglia. Last, we demonstrate that targeting CD200R in vivo can prevent visual dysfunction, microglia activation, and retinal inflammation in the diabetic mouse. These studies provide a molecular framework for the pivotal role that microglia play in early DR pathogenesis and identify a potential immunotherapeutic target for treating DR in patients.

Rodent Models of Diabetic Retinopathy as a Useful Research Tool to Study Neurovascular Cross-Talk

Diabetes is a group of metabolic diseases leading to dysfunction of various organs, including ocular complications such as diabetic retinopathy (DR). Nowadays, DR treatments involve invasive options and are applied at the sight-threatening stages of DR. It is important to investigate noninvasive or pharmacological methods enabling the disease to be controlled at the early stage or to prevent ocular complications. Animal models are useful in DR laboratory practice, and this review is dedicated to them. The first part describes the characteristics of the most commonly used genetic rodent models in DR research. The second part focuses on the main chemically induced models. The authors pay particular attention to the streptozotocin model. Moreover, this section is enriched with practical aspects and contains the current protocols used in research in the last three years. Both parts include suggestions on which aspect of DR can be tested using a given model and the disadvantages of each model. Although animal models show huge variability, they are still an important and irreplaceable research tool. Note that the choice of a research model should be thoroughly considered and dependent on the aspect of the disease to be analyzed.

The presence of diabetic retinopathy closely associated with the progression of non-alcoholic fatty liver disease: A meta-analysis of observational studies

Background and Objective: Although growing evidence indicates that non-alcoholic fatty liver disease is related to diabetic retinopathy (DR), research results significantly vary. Therefore, we conducted a meta-analysis to assess the association between the progression of non-alcoholic fatty liver disease and the onset of DR. Methods: PubMed, Embase, and Cochrane databases were searched until 7 November 2021. Combined odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the association. Results: We identified 18 studies involving 12,757 patients. The pooled effect assessment showed that liver fibrosis was positively correlated with DR (OR = 1.69, 95%CI 1.30-2.20; p < 0.0001); non-alcoholic fatty liver disease was not associated with the risk of DR (OR = 1.15, 95%CI 0.75-1.76; p = 0.51); non-alcoholic fatty liver disease was positively correlated with DR in patients with type 1 diabetes (OR = 2.96, 95%CI 1.48-5.94; p = 0.002). In patients with type 2 diabetes, there was no association between non-alcoholic fatty liver disease and DR (OR = 0.92, 95%CI 0.59-1.43; p = 0.70). Subgroup analysis showed no correlation in both Asian and Caucasian races. Conclusion: There is a significant correlation between liver fibrosis and DR. This suggests that the ocular examination of DR could be helpful in predicting whether patients with non-alcoholic fatty liver disease would progress to liver fibrosis.

Intense Pulsed Light on skin rejuvenation: a systematic review

Aged skin is characterized by appearance of wrinkles, vascular lesions, hyperpigmentation, lentignes, texture, rhytides, and pores. These changes occur under the influence of intrinsic and extrinsic factors, as hormone alterations and exposure to ultraviolet light (UV) irradiation, respectively. Skin changes associated with aging have been assuming an important role in nowadays and bring to affect the quality of life. Intense Pulsed Light (ILP) is a noncollimated, polychromatic, and noncoherent non-surgical cosmetic therapy to skin rejuvenation. This is the first systematic review evaluating ILP treatment on skin rejuvenation evaluated by digital photographs and self-reported treatment efficacy. A PRISMA compliant review includes a search of the databases Scopus and PubMed. Sixteen studies treating 637 participants (with Fitzpatrick skin types I to IV and age varying from 21 to 80 years) were included. Patients were treated a mean of 4.29 sessions (range 3-7). The most studies results showed the efficacy of IPL treatment in telangiectasia, wrinkles, pore, erythema, rhytids, texture, lentigines, hiperpigmentation, and photoaging score. Six studies showed IPL-positive effects in association with other treatment and seven studies showed superior effect of other treatment or association to IPL with other treatment related to IPL alone. Nine studies showed low methodological quality. In conclusion, ILP treatment is effective on skin rejuvenation. However, there is no consensus about the parameters and future studies are needed to sample size limitations, made RCTs with low risk of bias, and improve the methodological quality its. Trial registration: Prospero Systematic Review Registration ID: CRD42021237817.