Characterizing retinal structure injury in African-Americans with multiple sclerosis

Area of Science:

• Ophthalmology
• Neuroscience
• Immunology

Background:

• Multiple Sclerosis (MS) affects individuals of diverse ethnicities, with varying disease progression and severity.
• Retinal structure, particularly the nerve fiber layer, can serve as a biomarker for neurological damage in MS.
• Previous research suggests potential ethnic differences in MS pathology, but specific retinal structure impacts in African-Americans (AA) versus Caucasians (CA) require further investigation.

Purpose of the Study:

• To compare retinal structure injury, assessed via optical coherence tomography (OCT), between African-American (AA) and Caucasian (CA) patients with Multiple Sclerosis (MS).
• To investigate differences in specific retinal layers, including the peripapillary retinal nerve fiber layer (pRNFL) and macular volume, between ethnic groups with MS.
• To determine if these ethnic differences in retinal injury persist even in MS patients without a history of optic neuritis.

Main Methods:

• A cross-sectional study utilizing spectral domain optical coherence tomography (OCT) to measure retinal layers in 234 MS patients (149 CA; 85 AA) and 74 healthy controls (HC).
• Detailed intra-retinal segmentation was performed to quantify volumes of the retinal nerve fiber (RNFL), ganglion cell (GCL), inner plexiform (IPL), inner nuclear (INL), outer plexiform (OPL), outer nuclear (ONL), retinal pigment epithelium (RPE), and photoreceptor (PR) layers.
• Statistical analyses compared pRNFL thickness and macular volume between AA and CA MS patients, and between MS patients and HC, including a sub-analysis for patients with and without a history of anterior optic neuritis (AON).

Main Results:

• Healthy AA controls exhibited thicker pRNFL compared to healthy CA controls (100.9 vs 97.00μm).
• MS patients, across both ethnicities, showed significantly thinner pRNFL, reduced total macular volume (TMV), and decreased macular RNFL, GCL, and IPL volumes compared to HC.
• African-American MS (AAMS) patients demonstrated significantly thinner pRNFL and lower TMV, macular RNFL, and GCL volumes compared to Caucasian MS (CAMS) patients, even after excluding those with a history of AON.

Conclusions:

• This study provides evidence of greater retinal structure injury in African-American MS patients compared to Caucasian MS patients.
• The findings suggest that ethnic differences in CNS tissue injury may be reflected in the retina of MS patients.
• Retinal OCT parameters may offer valuable insights into disease severity and ethnic disparities in Multiple Sclerosis progression.