A Review of Biomarkers in Feline Hyperthyroidism: From Traditional Hormones to Emerging Omics

Background: Feline hyperthyroidism (FHT) is the most common endocrine disorder in middle-aged and geriatric cats. Early diagnosis is often difficult due to limitations of conventional biomarkers and the frequent presence of subclinical disease. Methods: A structured literature review (۲۰۰۰–۲۰۲۵) was conducted through PubMed, PMC, Web of Science, and Scopus. Classical hormonal biomarkers (TT۴, fT۴, TSH), systemic biomarkers (cardiac, renal, oxidative stress), and emerging omics biomarkers (metabolomics, proteomics, transcriptomics) were evaluated. Diagnostic sensitivity, specificity, assay methodology, and clinical relevance were extracted and analyzed. Results: TT۴ and fT۴ remain reliable for diagnosing overt FHT but often fail in early or borderline cases. The TSH-BAW assay provides improved sensitivity (۹۰.۵%) and specificity (۹۸.۹%), particularly for cats with borderline TT۴. Systemic biomarkers such as NT-proBNP and cTnI reveal cardiac involvement, whereas SDMA allows early detection of renal dysfunction masked by hyperthyroidism-induced muscle loss. Metabolomic analyses demonstrate persistent metabolic dysregulation post-radioiodine therapy, highlighting metabolites such as mevalonate, ribose, and creatine phosphate as potential clinical indicators. Limitations include small cohort sizes, variability in assays, and influences of diet or concurrent diseases. Conclusion: Integrating hormonal, systemic, and omics biomarkers offers a comprehensive strategy for early diagnosis, individualized treatment, and post-treatment monitoring of FHT. Further studies should focus on longitudinal validation, assay standardization, and translational application of omics findings in clinical practice.

کلیدواژه ها:

feline hyperthyroidism ، biomarkers ، TSH-BAW ، NT-proBNP ، metabolomics