Inflammatory orbital diseases encompass a broad range of conditions that affect the ocular orbit, often leading to vision impairment and discomfort. A recent review explored the significance of orbital fat in the pathogenesis of inflammatory orbital diseases, as well as its diagnostic implications and potential treatment approaches, and showed its protective and structural roles.
The researchers’ methods included a comprehensive literature review of articles identified through database searches in PubMed, MEDLINE, and other ophthalmology and pathology repositories. Studies were selected based on their focus on orbital fat metabolism, inflammation, imaging, and treatment approaches. Inclusion criteria prioritized original research, clinical studies, and systematic reviews related to inflammatory orbital diseases.
Orbital fat serves as a protective cushion for the vital structures housed in the orbit, including the eye, optic nerve, and extraocular muscles. While orbital fat has historically been regarded as a passive tissue, recent findings suggest it plays an active role in inflammatory processes. Indeed, “Inflammatory orbital diseases (IOD) account for up to 6% of orbital diseases, affecting patients across all age groups…A key feature of IOD is the diffuse infiltration of inflammatory cells within the orbital fat compartment,” wrote Prince Dadson, MD, PhD, MPH, of the Turku PET Centre, University of Turku and Turku University Hospital in Finland, with colleagues.
In their Ophthalmology and Therapy article, the researchers described the distinct metabolic properties that orbital fat exhibits compared with other adipose tissues including the production of pro-inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interleukin-1β (IL-1β); as well as macrophages, T cells, and B cells that are contained in orbital fat, among many others. These properties may contribute to immune responses and inflammation in conditions such as Graves' orbitopathy ophthalmopathy, sarcoidosis, and IgG4-related disease.
Advancements in imaging techniques, including computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET), have improved the detection of inflammatory orbital conditions. MRI is particularly useful in differentiating normal orbital fat from inflamed tissue, while PET scans offer the potential for early diagnosis by identifying metabolic activity associated with inflammation. Orbital fat biopsies have also been proposed as a diagnostic tool for assessing infiltrative lesions.
Management of inflammatory orbital diseases often involves corticosteroids, immunosuppressive agents, and surgical interventions, but the researchers also highlighted the emerging role of orbital fat-derived stem cells, which possess regenerative and anti-inflammatory properties. These stem cells are being investigated for potential uses in tissue repair and treatment of ocular surface injuries. Novel approaches such as orbital decompression surgery, targeted monoclonal antibody therapy, and radiotherapy are also being explored as therapeutic strategies for conditions involving orbital fat.
Further research into the immunologic activity and structural properties of orbital fat could lead to improved management of these complex conditions.
Full author disclosure information can be found in the published research