Short Communication - Journal of Clinical Ophthalmology (2022) Ocular infections: Immunology, Pathogenesis and Interventions
Biomarkers discovery for glaucoma: Future challenges and opportunities
Department of Ophthalmology, University of Lisboa, Lisbon, Portugal
- Corresponding Author:
- Dr. San Arrie
Department of Ophthalmology
University of Lisboa
E-mail: [email protected]
Received: 02-Feb-2022, Manuscript No. AACOVS-22-57992; Editor assigned: 04-Feb-2022, PreQC No. AACOVS-22-57992 (PQ); Reviewed: 18-Feb-2022, QC No. AACOVS-22-57992; Revised: 22-Feb-2022, Manuscript No. AACOVS-22-57992 (R); Published: 01-Mar-2022, DOI: 10.35841/aacovs.6.S7.525-526.
Citation: Arrie S. Biomarkers discovery for glaucoma: Future challenges and opportunities. J Clin Ophthalmol 2022;6(S7):525-526.
Biomarkers provide a powerful and dynamic approach to improve our understanding of the mechanisms underlying ocular diseases with applications in diagnosis, disease modulation or for predicting and monitoring of clinical response to treatment. Defined as measurable indicator of normal or pathological processes, biomarker evaluation has been used extensively in drug development within clinical settings to better comprehend effectiveness of treatment in glaucoma diseases. Biomarkers can change qualitatively (mutation/s) or quantitatively (expression level). An ultimate goal is the application of such information for diagnostic and potentially even for screening purposes. New technologies such as disease proteomics and transcriptomics open new perspectives for the development of rapid molecular diagnostics and follow-up in glaucoma. This article describes the usage of biomarkers with respect to commonly sampled glaucoma in clinic: Primary Open Angle Glaucoma, Angle Closure Glaucoma, Normal Tension Glaucoma, and Secondary Glaucoma.
Glaucoma, Biomarkers, Optic nerve, Vision loss.
The eye is a complex sensory organ that receives light and converts it into electrical impulses that are transmitted to the brain by the optic nerve, resulting in visual perception. Broadly speaking, it can be divided into anterior and posterior sections. The anterior part contains the cornea, conjunctiva, aqueous humor, iris, ciliary body and lens, while the posterior segment contains the sclera, choroid, retina and vitreous. Glaucoma is a group of eye diseases that damage the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, which has a drainage angle open for fluid inside the eye, less common types including close-angle (narrow angle, acute circulatory) glaucoma and normal-tension glaucoma. Open-angle glaucoma develops slowly over time and is painless. Peripheral vision begins to decline, followed by central vision, which can lead to blindness if left untreated. Closed angle glaucoma can be gradual or sudden. Sudden onset may include severe eye pain, blurred vision, mid-enlarged pupil, redness of the eye and nausea. Vision loss from glaucoma, once it occurs, is permanent. Glaucoma-infected eyes are referred to as glaucomatous .
Molecular biomarkers in glaucoma have not yet been explored. Currently, glaucoma management examines the structure and function of nerve tissue in the back of the eye. The ophthalmologists try to diagnose whether the patient's retinal or optic nerve tissue is lost and in addition there is a reduced sensitivity to light in the visual fields. Identifying molecular biomarkers for glaucoma promises many possible benefits. These important areas of clinical practice are still being actively researched and continue to yield promising results.
However, the benefit of detecting molecular biomarkers that are active when a patient's nerve tissue is injured is to provide the clinician with a new tool to track progress before the tissue is permanently lost and the visual field deteriorates further . There may be hypothetical use of a molecular biomarker to help guide more specific treatment in some glaucoma patients. For example, it may help a glaucoma physician to know when to intervene first. In addition, a biomarker can be used to demonstrate the efficacy of pharmacological activity, accelerating federal approval for glaucoma drugs, especially those that protect the retina and optic nerve.
The new technologies like transcrptomics and proteomics biomarkers are promising tools for identification of glaucoma disease. Transcriptomics refers to the large-scale analysis of a transcriptome, a set of all mRNA molecules transcribed from a gene. The evaluation of transcriptomes in eye diseases has so far been done primarily through RNA microarray experiments, although this is likely to shift more towards RNA sequencing (RNA seq). RNA seq is currently more expensive than microarrays, but has the advantage of identifying nonannotated sequences and alternative splice variants next to expression levels. Recently, studies examining the expression of noncoding, regulatory RNAs, micro RNAs (mRNAs) and long-noncoding RNAs (LncRNAs) have also been reported in ophthalmology. miRNAs specifically target mRNAs and affect the level of these targets and subsequent protein production . LncRNAs control both transcription and translation through various mechanisms. Disease-specific miRNA and lncRNA profiles have been extensively studied in many diseases over the past few years and miRNAs and lncRNAs, unlike other RNAs, are interesting biomarker candidates because they are stable in circulation. In addition, evaluating their target mRNAs provides insight into pathogenic processes [4-5].
Recently, proteomic studies characterized glaucoma-specific proteomes in tears, which might be an interesting source to further explore in the future, particularly because of the noninvasive nature of tear collection. The higher presence of immune-related proteins in serum of glaucoma patients was already known, and serum antibodies with target antigens in eye tissues were the main proteins screened for biomarker discovery in the past. Furthermore, mass spectrometric analyzes of oxidative changes might be valuable because these changes are common in glaucoma patients and act as biomarkers. Overall, several biomarkers have been proposed based on proteomic analysis, but still require further verification in large integrations and their clinical needs to be confirmed. Early stage biomarkers are especially valuable contributors to the clinic because glaucoma is often not detected until irreversible damage to the optic nerve has already occurred [6-8].
The Glaucoma Research Foundation will be emphasizing research into biomarkers for glaucoma to stimulate activity in this area. The identification of a metabolic marker indicating tissue injury with accuracy could potentially help predict glaucoma in patients who do not yet show symptoms of vision loss. Such a marker could help doctors treating glaucoma know whether the patient is likely to progress and therefore treat the disease more aggressively or whether treatment is even required in certain patients. In the search for a glaucoma biomarker, we hope to find a tool to predict accurately and early if tissue is damaged and with greater sensitivity than the diagnostic tools currently available. Such a biomarker might serve as an early indicator for disease monitoring and intervention.
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