Pathogenesis of ocular tuberculosis: New observations and future directions

Abstract

Ocular tuberculosis (OTB) encompasses all forms of intra-and extra-ocular inflammation associated with Mycobacterium tuberculosis (Mtb) infection. However, the organism is rarely found in ocular fluid samples of diseased eyes, rendering the pathomechanisms of the disease unclear. This confounds clinical decision-making in diagnosis and treatment of OTB.Here, we critically review existing human and animal data related to ocular inflammation and TB pathogenesis to unravel likely pathomechanisms of OTB. Broadly there appear to be two fundamental mechanisms that may underlie the development of TB-associated ocular inflammation: a. inflammatory response to live/ replicating Mtb in the eye, and b. immune mediated ocular inflammation induced by non-viable Mtb or its components in the eye. This distinction is significant as in direct Mtb-driven mechanisms, diagnosis and treatment would be aimed at detection of Mtb-infection and its elimination; while indirect mechanisms would primarily require anti-inflammatory therapy with adjunctive anti-TB therapy. Further, we discuss how that most clinical phenotypes of OTB likely represent a combination of both mechanisms, with one being predominant than the other.

Role of extracellular mycobacteria in blood-retinal barrier invasion in a zebrafish model of ocular TB

“…Our results would have implications on the early events that decide the clinical phenotype and the time to onset of disease in ocular TB. Ocular TB has distinct phenotypes that are known to affect tissues that are either inside or outside the BRB though occasionally both could be affected [29] Government of India, were followed for zebrafish maintenance and experimentation.…”

Role of Extracellular Mycobacteria in Blood-Retinal Barrier Invasion in a Zebrafish Model of Ocular TB

“…Our results have implications for the early events that decide the clinical phenotype and time to onset of disease in ocular TB. Ocular TB has distinct phenotypes that are known to affect tissues either inside or outside the BRB, and occasionally both [29]. The former include retinitis and retinal vasculitis, whereas choroiditis, cyclitis, and iritis are examples of the latter.…”

Histologisch diagnostizierte okuläre und periokuläre Tuberkulose von 1945 bis 2020

“…2 ), insgesamt handelte es sich bei diesem Kriterium jedoch um das am wenigsten häufige und bei der Nachbefundung am wenigsten konsistent bewertete Gewebemerkmal. Eine aktuelle Übersichtsarbeit beschreibt eine Nekrose als Diagnosemerkmal im hinteren, jedoch nicht im vorderen Augenabschnitt bei intraokularer Tbc 20 . Eine weitere Arbeit legt den Fokus auf systemische Tbc-Diagnostik.…”