Exploring the connection between HLA class I and class II genotypes and diabetic retinopathy: A comprehensive review of experimental evidence

Diabetic retinopathy (DR) is a microvascular complication associated with diabetes mellitus (DM). During the course of the disease, high blood glucose levels induce damage to the vasculature of the retina and promote neovascularization. Although numerous environmental risk factors have been associated with the emergence of DR, the role of genetics should not be underestimated. The human leukocyte antigen (HLA) plays a significant role in the regulation of the immune system. DR exhibits significant heterogeneity among patients, with differences in how the disease presents and progresses over time. The HLA gene, characterized by its extensive genetic variation, largely contributes to this diverse spectrum. Differences in HLA allele frequencies among healthy people, diabetic patients without retinopathy, and diabetic patients with different stages of retinopathy highlight the need for proper management of the disease. This comprehensive review outlines the current understanding of the relationship between HLA class I and class II variants and DR, shedding light on their potential significance as early onset indicators, prognostic indicators, and important risk factors for the development of this retinal condition.

DGHNE: network enhancement-based method in identifying disease-causing genes through a heterogeneous biomedical network

The identification of disease-causing genes is critical for mechanistic understanding of disease etiology and clinical manipulation in disease prevention and treatment. Yet the existing approaches in tackling this question are inadequate in accuracy and efficiency, demanding computational methods with higher identification power. Here, we proposed a new method called DGHNE to identify disease-causing genes through a heterogeneous biomedical network empowered by network enhancement. First, a disease-disease association network was constructed by the cosine similarity scores between phenotype annotation vectors of diseases, and a new heterogeneous biomedical network was constructed by using disease-gene associations to connect the disease-disease network and gene-gene network. Then, the heterogeneous biomedical network was further enhanced by using network embedding based on the Gaussian random projection. Finally, network propagation was used to identify candidate genes in the enhanced network. We applied DGHNE together with five other methods into the most updated disease-gene association database termed DisGeNet. Compared with all other methods, DGHNE displayed the highest area under the receiver operating characteristic curve and the precision-recall curve, as well as the highest precision and recall, in both the global 5-fold cross-validation and predicting new disease-gene associations. We further performed DGHNE in identifying the candidate causal genes of Parkinson's disease and diabetes mellitus, and the genes connecting hyperglycemia and diabetes mellitus. In all cases, the predicted causing genes were enriched in disease-associated gene ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways, and the gene-disease associations were highly evidenced by independent experimental studies.

The role of pharmacogenetics and advances in gene therapy in the treatment of diabetic retinopathy

Diabetic retinopathy (DR) and its complications such as diabetic macular edema continue to remain a major cause for legal blindness in the developed world. While the introduction of anti-tVEGF agents has significantly improved visual outcomes of patients with DR, unpredictable response, largely due to genetic polymorphisms, appears to be a challenge with this therapy. With advances in identification of various genetic biomarkers, novel therapeutic strategies consisting of gene transfer are being developed and tested for patients with DR. Application of pharmacogenetic principles appears to be a promising futuristic strategy to attenuate diabetes-mediated retinal vasculopathy. In this comprehensive review, data from recent studies in the field of pharmacogenomics for the treatment of DR have been provided.

[Susceptibility genes, HLA and diabetic retinopathy in the Algerian population]

BACKGROUND

Diabetic retinopathy (DR) is the most frequent microvascular complication of type I diabetes (T1D). Some well-controlled type I diabetics may develop DR, while other poorly-controlled diabetics do not develop DR. This might be explained by certain susceptibility genes or protective genes. The purpose of our study is to search for any association between the HLA class I and II markers and DR in the Algerian population.

PATIENTS AND METHODS

This study was carried out in 52 T1D subjects with and without DR compared to 140 healthy controls. HLA typing was performed using the "microlymphocytotoxicity" technique.

RESULTS

The frequency of HLA-A29 and HLA-DR9 antigens is higher in T1D with DR compared to T1D without DR and to controls with frequencies of HLA-A29 (59.26% vs. 0%, OR=∞, pc=4.6×10(-7)), (59.26% vs. 5.66%, OR=24.24, pc=7.6×10-10) and HLA-DR9 (29.63% vs. 0%, OR=∞, pc=1.310(-3)), (29.63% vs. 4.29%, OR=9.40, pc=7.010(-5)) respectively. However, the frequency of HLA-B49 antigen is significantly lower in T1D with DR than in T1D without DR (3.7% vs. 28%, OR=0.10, pc=8.8×10(-3)) and compared to controls (3.7% vs. 22.64%, OR=0.13, pc=0.011).

CONCLUSION

HLA-A29 and HLA-DR9 antigens are probably markers of susceptibility for DR while HLA-B49 antigen is probably associated with a protective effect in the Algerian population.