Homocysteine and diabetic retinopathy.

Area of Science:

• Ophthalmology
• Endocrinology
• Neuroscience

Background:

• Diabetic retinopathy (DR) is a leading cause of blindness.
• Chronic hyperglycemia is a known risk factor for DR.
• Emerging evidence suggests hyperhomocysteinemia (HHcy) also plays a critical role in DR progression.

Purpose of the Study:

• To review the multifaceted role of HHcy in the neurovascular complications of DR.
• To elucidate the molecular mechanisms by which HHcy contributes to retinal damage.
• To evaluate the therapeutic potential of targeting HHcy metabolism in DR.

Main Methods:

• Literature review of preclinical and clinical studies on HHcy and DR.
• Analysis of molecular pathways implicated in HHcy-induced retinal injury.
• Critical evaluation of translational evidence and therapeutic strategies.

Main Results:

• HHcy disrupts the retinal neurovascular unit, affecting endothelial cells, neurons, glial cells, and the retinal pigment epithelium.
• Molecular mechanisms include oxidative stress, inflammation, ER stress, mitochondrial dysfunction, and epigenetic changes.
• Preclinical studies show HHcy synergizes with hyperglycemia to cause retinal injury, but clinical evidence is inconsistent.

Conclusions:

• HHcy is a significant, yet under-recognized, factor in DR pathogenesis.
• Targeting HHcy metabolism with B vitamins or betaine shows therapeutic promise.
• Well-designed clinical trials are essential to validate HHcy as a modifiable risk factor and guide personalized DR interventions.