Intravital Imaging of Pulmonary Immune Response in Inflammation and Infection

Abstract

Intravital microscopy (IVM) is a unique imaging method providing insights in cellular functions and interactions in real-time, without the need for tissue extraction from the body. IVM of the lungs has specific challenges such as restricted organ accessibility, respiratory movements, and limited penetration depth. Various surgical approaches and microscopic setups have been adapted in order to overcome these challenges. Among others, these include the development of suction stabilized lung windows and the use of more advanced optical techniques. Consequently, lung IVM has uncovered mechanisms of leukocyte recruitment and function in several models of pulmonary inflammation and infection. This review focuses on bacterial pneumonia, aspiration pneumonia, sepsis-induced acute lung Injury, and cystic fibrosis, as examples of lung inflammation and infection. In addition, critical details of intravital imaging techniques of the lungs are discussed.

Neutrophil Recruitment in Pneumococcal Pneumonia

“…Improved models of neutrophil recruitment throughout infection may help elucidate our understanding of the contribution of these immune effectors to the pathophysiology of Spn infection. Although murine models have allowed us to gain a better understanding of neutrophil recruitment, the application of other physiologically relevant models such as human organoids (Gkatzis et al, 2018), intravital microscopy (Alizadeh-Tabrizi et al, 2021), and humanized mice (Zheng et al, 2022) to the study of pneumococcal pneumonia will be indispensable in developing our understanding of human infection.…”

Selective CB2 Receptor Agonist, HU-308, Reduces Systemic Inflammation in Endotoxin Model of Pneumonia-Induced Acute Lung Injury

“…In an intranasal model, LPS solution enters the lungs via proximal airways. Conversely, the low penetration depth of conventional fluorescence imaging limits lung IVM to distal airway regions, i.e., the subpleural microvasculature [ 47 ]. Thus, it is quite possible that inflammation does not spread to the imaged region, which is therefore not representative of the sought-after immune response.…”

Multimodal imaging and deep learning unveil pulmonary delivery profiles and acinar migration of tissue-resident macrophages in the lung

“…Direct imaging of phagocytosis and patrolling of TRMs could supplement the static information on macrophage uptake, migratio, and associated NP relocation. Lung IVM was recently used to unveil cellular circuits during e.g., viral infection, bacterial clearance, disease progression, tissue inflammation, and immune responses in the lungs of living mice 24,45,46 . This study adapted in vivo (Figure 5a) and ex vivo living tissue microscopy 47 (Figure 5b) to observe cellular dynamics of TRMs during NP ingestion after both administrations.…”