Bevacizumab reverts serous retinal detachment caused by tuberculosis-associated immune reconstitution inflammatory syndrome

The first-in-class pyrazole-based dual InhA-VEGFR inhibitors towards integrated antitubercular host-directed therapy

Several facets of the host response to tuberculosis have been tapped for clinical investigation, especially targeting angiogenesis mediated by VEGF signaling from infected macrophages. Herein, we rationalized combining the antiangiogenic effects of VEGFR-2 blockade with direct antitubercular InhA inhibition in single hybrid dual inhibitors as advantageous alternatives to the multidrug regimens. Inspired by expanded triclosans, the ether ligation of triclosan was replaced by rationalized linkers to assemble the VEGFR-2 inhibitors thematic scaffold. Accordingly, new series of 3-(p-chlorophenyl)-1-phenylpyrazole derivatives tethered to substituted ureas and their isosteres were synthesized, evaluated against Mycobacterium tuberculosis virulent cell line H37Rv, and assessed for their InhA inhibitory activities. The urea derivatives 8d and 8g exhibited the most promising antitubercular activity (MIC = 6.25 µg/mL) surpassing triclosan (MIC = 20 µg/mL) with potential InhA inhibition, thus identified as the study hits. Interestingly, both compounds inhibited VEGFR-2 at nanomolar IC50 (15.27 and 24.12 nM, respectively). Docking and molecular dynamics simulations presumed that 8d and 8g could bind to their molecular targets InhA and VEGFR-2 posing essential stable interactions shared by the reference inhibitors triclosan and sorafenib. Finally, practical LogP, Lipinski's parameters and in silico ADMET calculations highlighted their drug-likeness as novel leads in the arsenal against TB.

Host-directed therapies targeting the tuberculosis granuloma stroma

Mycobacteria have co-evolved with their hosts resulting in pathogens adept at intracellular survival. Pathogenic mycobacteria actively manipulate infected macrophages to drive granuloma formation while subverting host cell processes to create a permissive niche. Granuloma residency confers phenotypic antimicrobial resistance by physically excluding or neutralising antibiotics. Host-directed therapies (HDTs) combat infection by restoring protective immunity and reducing immunopathology independent of pathogen antimicrobial resistance status. This review covers innovative research that has discovered ‘secondary’ symptoms of infection in the granuloma stroma are actually primary drivers of infection and that relieving these stromal pathologies with HDTs benefits the host. Advances in our understanding of the relationship between tuberculosis and the host vasculature, haemostatic system and extracellular matrix reorganisation are discussed. Preclinical and clinical use of HDTs against these stromal targets are summarised.

Revisiting hypoxia therapies for tuberculosis

The spectre of the coming post-antibiotic age demands novel therapies for infectious diseases. Tuberculosis (TB), caused by Mycobacterium tuberculosis, is the single deadliest infection throughout human history. M. tuberculosis has acquired antibiotic resistance at an alarming rate with some strains reported as being totally drug resistant. Host-directed therapies (HDTs) attempt to overcome the evolution of antibiotic resistance by targeting relatively immutable host processes. Here, I hypothesise the induction of hypoxia via anti-angiogenic therapy will be an efficacious HDT against TB. I argue that anti-angiogenic therapy is a modernisation of industrial revolution era sanatoria treatment for TB, and present a view of the TB granuloma as a 'bacterial tumour' that can be treated with anti-angiogenic therapies to reduce bacterial burden and spare host immunopathology. I suggest two complementary modes of action, induction of bacterial dormancy and activation of host hypoxia-induced factor (HIF)-mediated immunity, and define the experimental tools necessary to test this hypothesis.

Tuberculous Uveitis Presenting with a Bullous Exudative Retinal Detachment: A Case Report and Systematic Literature Review

Purpose: To describe tuberculous uveitis (TU) presenting as a bullous retinal detachment (RD) and to perform a comprehensive literature review on TU with similar features. Methods: Observational case report and systematic literature review. Results: An 84-year-old woman presented with bilateral granulomatous uveitis and bullous RD in the left eye. The interferon gamma release assay was strongly positive, but all other tests were unremarkable. The patient was diagnosed with TU and started on anti-tubercular therapy (ATT) and systemic steroids with excellent treatment response. Twenty-six articles (32 cases) reported TU with exudative RD. Choroidal tuberculoma was the most common clinical manifestation, followed by optic disc edema and retinal exudate. Systemic steroids with ATT improved vision in more patients (78.6%) than ATT alone (50.0%) or oral steroids followed by ATT (50.0%). Conclusion: Atypical presentations of TU make diagnosis and treatment difficult. A high level of suspicion for TU is needed to minimize ocular morbidity.

Bevacizumab for paradoxical worsening treatment adjunct in HIV patient with choroidal tuberculoma

The use of anti-tubercular therapy (ATT) along with anti-retroviral therapy (ART) in human immunodeficiency virus-tuberculosis (HIV-TB) co-infected individuals could at times lead to paradoxical worsening due to an increase in the inflammatory activity due to immune reconstitution inflammatory syndrome (IRIS) in the eye. This is characterized by anterior and posterior segment inflammatory reactions which may occur in the form of serous retinal detachment. We describe a case where the use of intravitreal anti-vascular endothelial growth factor (anti-VEGF) agent led to resolution of the serous retinal detachment, which had failed to respond to other common modalities of treatment.

An HIV-TB co-infected 18-year-old, male patient, who was started on ART and ATT developed IRIS in the form of worsening of serous retinal detachment around a pre-existent asymptomatic tuberculoma. The patient was initially treated with oral and topical steroids without a satisfactory response. Intravitreal bevacizumab was then tried for this patient. Serial fundus photos and optical coherence tomography (OCT) taken before and after treatment showed complete resolution of the serous retinal detachment with two doses of intravitreal bevacizumab.

Intravitreal anti-VEGF agents may have a role in the reversal of serous retinal detachment, which occurs as a part of IRIS in HIV-tuberculosis co-infected individuals who have been started on anti-tubercular and anti-retroviral therapies.