Potential biomarkers of primary open-angle glaucoma in patient serum in Nigeria

(image Credit: AdobeStock/kamiphotos)

Researchers in Nigeria found a number of biomarkers in the serum analyses of patients with primary open-angle glaucoma (POAG) that they believe have “high potential” and should be investigated further.¹ Abdulkabir Ayansiji Ayanniyi, MD, the first study author from the Departments of Ophthalmology, University of Abuja, and the University of Abuja Teaching Hospital, Gwagwalada, Abuja, Nigeria, shared the findings in International Ophthalmology.

A total of 235 adults who were ophthalmology patients were included; of these, 96 had been diagnosed with POAG and 139 did not. The mean patient ages with and without POAG were, respectively, 53.70 ± 13.15 years and 46.05±14.00 years (range, 18-85 years); 48.5% were men. All participants provided fasting blood samples and the samples were analyzed for urea and creatinine, electrolytes, enzymes, protein, bilirubin, and lipids, the researchers reported.

The investigators reported the following significant mean changes in the patients with POAG and the non-POAG patients, respectively: urea 37.04 ± 2.46 vs. 27.01 ± 1.00, P = 0.000; creatinine 1.08 ± 0.16 vs. 1.68 ± 0.15, P = 0.007; chloride 86.47 ± 2.91 vs. 78.63 ± 1.43, P = 0.017; alkaline phosphatase 17.47 ± 1.93 vs. 93.09 ± 13.87, P = 0.000; alanine aminotransferase 3.33 ± 0.61 vs. 14.95 ± 1.49, P = 0.000; total protein 5.60 ± 0.15 vs. 6.03 ± 0.09, P = 0.015; and globulin 2.34 ± 0.15 vs. 2.75 ± 0.09, P = 0.020.

The analyzed factors that did not reach significance were: sodium 140.16 ± 3.82 vs. 124.83 ± 3.17, P = 0.953; potassium 4.70 ± 0.19 vs. 4.67 ± 0.25, P = 0.29; aspartate aminotransferase 16.90 ± 1.57 vs. 21.37 ± 7.85, P = 0.258; albumin 3.26 ± 0.09 vs. 3.28 ± 0.05, P = 0.83; direct bilirubin 0.61 ± 0.04 vs. 0.57 ± 0.04, P = 0.32; total bilirubin 0.53 ± 0.06 vs. 0.90 ± 0.16, P = 0.14; cholesterol 169.39 ± 6.30 vs. 214.17 ± 4.60, P = 0.078; high density lipoprotein (HDL) 49.53 ± 2.58 vs. 45.11 ± 0.76, P = 0.104; and triglyceride 80.12 ± 4.79 vs. 91.44 ± 3.84, P = 0.271.

Ayanniyi and colleagues suggested that the significant serum parameters should be further investigated to determine their specificity as biomarkers for POAG.

Previous POAG research

In a previous study of POAG, lead co-authors Yaping Yang and Bo Qin, from the Department of Ophthalmology and Visual Science, Eye and Ear Nose Throat Hospital, Shanghai Medical College; the Key Laboratory of Myopia, Ministry of Health; and the Key Laboratory of Visual Impairment and Restoration, all in Fudan University, Shanghai, China, and colleagues also evaluated the serum lipid profiles of Chinese patients with POAG and assessed the disease correlation with the intraocular pressure (IOP). They compared the results to patients with primary angle-closure glaucoma (PACG).²

The study included 1,139, 1,248, and 356 Chinese individuals with, respectively, POAG, PACG, and controls. The lipids evaluated were HDL, low-density lipoproteins (LDL), triglycerides, cholesterol, and very low-density lipoproteins (VLDL). They also quantified the lipid levels of apolipoproteins A (APOA), B (APOB), E (APOE), and lipoprotein A (Lp(a)).

The authors reported that the patients with POAG had elevated serum levels of VLDL, APOA, and APOE but mitigated cholesterol levels compared with the control participants.

Significantly lower serum triglyceride, VLDL, and Lp(a) levels were seen in patients with PACG compared with the controls.

The authors also observed that the serum cholesterol (P = 0.019; β = -0.75, 95% confidence interval [CI]: -1.38 – -0.12) and HDL levels (P < 0.001; β = -2.91, 95% CI: -4.58 – -1.25) were inversely linked to IOP in patients with POAG, after adjusting for age, sex, and ocular metrics. In addition, serum Lp(a) levels were correlated with the average IOP (P = 0.023; β = -0.0039, 95% CI: -0.0073 – -0.006) and night peak (P = 0.027; β = -0.0061, 95% CI: -0.0113 – -0.0008) in patients with POAG.

“Significantly different serum lipid and lipoprotein profiles were observed in POAG and PACG patients. This study highlighted the differences in serum lipid and lipoprotein levels among Chinese POAG patients and their relationship with IOP and IOP fluctuation. Serum lipid and lipoprotein profiles should be considered while evaluating glaucoma risk,” the investigators concluded.

Further POAG study

In another POAG study, Mustafa Kalayci, MD, from the Department of Ophthalmology, Somalia Mogadishu - Turkey Education and Research Hospital, Mogadishu, Somalia, and the Department of Ophthalmology, Antalya Training and Research Hospital, University of Health Sciences, Antalya, Turkey, and colleagues, reported a high rate of development of POAG in Somalia in patients older than 40 years.³

Their prospective cross-sectional study included 1550 patients who were evaluated regarding age, gender, intraocular pressure, and optical cup/disk ratio, and central corneal thickness measurements.

The authors reported that the prevalence of glaucoma in the study population over 40 years of age was 7%.

Specifically, by decades of age they found that the prevalence rates increased with increasing age (P < 0.001): 40% in the 40- to 50-year group, 6.8% in the 50- to 60-year group, 7% in the 60- to 70-year group, 9.9% in the 70- to 80-year group, and 12.3% in the 80- to 90-year group.

The authors commented, “A high rate of POAG was seen in patients over 40 years of age in Somalia. The mechanism underlying POAG needs to be investigated in this population.”

References

1. Ayanniyi AA, Mahmoud AO, JohnSam YO, et al. Survey of eye patients’ serum for biomarkers of primary open angle glaucoma in Gwagwalada, Nigeria: serum biomarkers for primary open angle glaucoma. Int Ophthalmol. 2025;45:151. https://doi.org/10.1007/s10792-025-03519-0

2. Yang Y, Qin B, Ng TK, et al. Serum lipid and lipoprotein profiles and their association with intraocular pressure in primary open-angle glaucoma: an observational cross-sectional study in the Chinese population. Lipids Health Dis. 2024;23, 323. https://doi.org/10.1186/s12944-024-02316-5

3. Kalayci M, Cetinkaya E, Erol MK. Prevalence of primary open-angle glaucoma in a Somalia population. Int Ophthalmol. 2021;41:581–586. https://doi.org/10.1007/s10792-020-01612-0