Citoquinas séricas proinflamatorias en retinopatía diabética

Interleukin-6 and Diabetic Retinopathy: A Systematic Review and Meta-Analysis

BACKGROUND

Interleukin-6 (IL-6) is produced by a variety of cells involved in inflammation and acts as local intensification signals in pathological processes associated with chronic eye inflammation. This meta-analysis was performed to provide a better understanding of the relationship between IL-6 and diabetic retinopathy.

METHODS

The study was started with systematic search for literatures by using the PubMed, Web of Science and Embase online databases. The standard mean difference (SMD) and its 95% confidence intervals (CIs) were was included and then pooled with a random effects model.

RESULTS

Thirty-one articles, containing1099 DR patients and 1010 controls, were included in this meta-analysis. The level of IL-6 in the DR group was found to be higher than that in the control group (SMD: 2.12, 95% CI: 1.53-2.70, p < 0.00001).Obvious heterogeneity existed between the studies (p < 0.00001, I² = 96%). So a subgroup analysis and sensitivity analysis were performed. Removing the sensitivity studies, the stability of the overall treatment effect was good. Subgroup analysis showed that the levels of IL-6 in case group were observed to be higher than those in the control group; and the IL-6 levels in the proliferative diabetic retinopathy (PDR) group were also higher than those in the non-proliferative diabetic retinopathy (NPDR) group. (SMD: 0.78, 95% CI: 0.26-1.31, p=  0.003) Conclusion: The results from this current meta-analysis indicated that increased level of IL-6 generally exist in DR patients. And it may associated with the severity of DR. However, large-scale and high-quality studies in future are required to confirm the present findings.

Tumor necrosis factor-α and diabetic retinopathy: Review and meta-analysis

BACKGROUND

Tumor necrosis factor-alpha (TNF-α) is produced by multinuclear giant cells and acts as local intensification signals in pathological processes associated with chronic eye inflammation. This meta-analysis was performed to provide a better understanding of the relationship between TNF-α and diabetic retinopathy (DR).

METHOD

Online electric databases were searched to retrieve all relevant articles published before October 2017. The standard mean difference (SMD) and their 95% confidence intervals (CI) were included and then pooled with a random effects model.

RESULTS

A total of 16 articles with 1286 participants were included in this meta-analysis. No difference in the level of TNF-α was found between DR patients and healthy controls (SMD = 0.39, 95% CI = -0.09 to 0.68, P = 0.01). Subgroup analysis showed that with respect to the level of TNF-α, the association was significant for studies conducted in Europe (SMD: 0.57, 95% CI: 0.11-1.02, P = 0.01), patients with type 1 DM (SMD: 1.06, 95% CI: 0.09-2.04, P = 0.03), studies based on serum samples (SMD: 0.57, 95% CI: 0.12-1.02, P = 0.01) and studies with a sample size >50 (SMD: 0.39, 95% CI: 0.03-0.75, P = 0.04).

CONCLUSION

The results this meta-analysis indicated that the level of TNF-α in DR patients was significantly different from that in the healthy controls, so TNF-α represents a candidate biomarker for DR.

Effects of fenofibrate on inflammatory cytokines in diabetic retinopathy patients

The role of cytokines in diabetic retinopathy (DR) and effects of fenofibrate on cytokines were explored by observing changes in serum IL-1β, TNF-α, VEGF, and Lp-PLA2 in different stages of DR and the intervention effect of oral fenofibrate on cytokines.In total, 190 patients with type 2 DR were enrolled and divided into 3 groups: diabetic without retinopathy (NDR) group (n = 30), nonproliferative diabetic retinopathy (NPDR) group (n = 80), and proliferative diabetic retinopathy (PDR) group (n = 80). According to whether or not to accept fenofibrate treatment, NPDR and PDR groups were further divided into the NPDR control (NPDR1) group (n = 40) and the NPDR treatment (NPDR2) group (n = 40), and the proliferative diabetic retinopathy control (PDR1, n = 40) group and the proliferative diabetic retinopathy treatment (PDR2) group (n = 40). At 12 weeks after fenofibrate treatment, serum IL-1β, TNF-α, VEGF, and Lp-PLA2 levels were detected.In PDR and NPDR patients, levels of serum cytokines such as IL-1β (120.56 ± 27.32 pg/mL vs 112.34 ± 19.45 pg/mL vs 82.9 ± 13.8 pg/mL), TNF-α (125.86 ± 25.57 pg/mL vs 109.48 ± 20.15 pg/mL vs 80.7 ± 12.8 pg/mL), VEGF (166.65 ± 37.74 pg/mL vs 148.54 ± 36.27 pg/mL vs 88.97 ± 24.86 pg/mL), and Lp-PLA2 (172.34 ± 45.22 μg/L vs 154.66 ± 40.98 μg/L vs 125.88 ± 38.87 μg/L) were significantly higher than in diabetes patients without retinopathy. After fenofibrate treatment, serum IL-1β, TNF-α, VEGF, and Lp-PLA2 significantly decreased in NPDR and PDR patients.Serum IL-1β, TNF-α, VEGF, and Lp-PLA2 play an important role in occurrence and development of diabetic retinopathy. Fenofibrate can reduce cytokine levels in DR patients and improve inflammatory response.