Translational Approaches and Preclinical Modeling to Address the Unmet Needs of Ards/Vili

Abstract

Acute Respiratory Distress Syndrome (ARDS) is a serious critical care illness that occurs as a complication of predisposing conditions such as sepsis, trauma, acid aspiration, and bacteria- and virus-induced pneumonias. ARDS has high mortality rate of 30-40% (pre-COVID 19 pandemic). As the unprecedented pandemic of COVID-19 has increased the need to find effective FDA-approved ARDS therapies, the goal of the current study is to address three key unmet needs in ARDS/ventilation-induced lung injury (VILI). The first unmet need is to find novel FDA-approved ARDS therapeutics that reduce the severity and mortality of ARDS/VILI. The second unmet need is to develop large animal models of ARDS/VILI that recapitulate features of human ARDS/VILI and allow for effective validation of potential biomarkers and testing of novel therapeutics. The third unmet need is to obtain novel phenotypic tools to fully assess preclinical lung fluid imbalance and multi-organ dysfunction. Numerous potential ARDS therapeutics, based upon preclinical rodent studies that utilized lipopolysaccharide (LPS) as the insult without further lung injury related to mechanical ventilation (MV), have failed in human clinical trials. Previously, we utilized preclinical multispecies ARDS models coupled with genomic-intensive approaches to identify novel ARDS biomarkers and targetable pathways. We identified nicotinamide phosphoribosyltransferase (NAMPT) as a novel damage-associated molecular pattern (DAMP) protein and attractive ARDS target. Our data demonstrated that the intravenous administration of an eNAMPT-neutralizing polyclonal antibody (pAb) significantly attenuated the severity of murine VILI. In the current study, we examine humanized eNAMPT-neutralizing monoclonal antibodies (mAbs) for potential therapeutic efficacy in rodent LPS/VILI models and apply the lead mAb, ALT-100 mAb, in an innovative ARDS/VILI porcine model that we have developed. In addition, we evaluate phenotypic tools, such as chest ultrasound and radiograph, to fully assess the lung fluid imbalance in the preclinical models and evaluate the eNAMPT ALT-100 mAb efficacy on ARDS-induced acute kidney injury (AKI), as part of the ARDS multi-organ dysfunction. Methods. Sprague Dawley (SD) rats were challenged with intratracheal (IT) LPS. Eighteen hours (18 hr) later, animals were either harvested “one-hit model” or connected to high tidal volume (Vt) mechanical ventilation (MV) for 4 hr before harvesting “two-hit model”. Animals received eNAMPT ALT-100 mAb concurrently with LPS instillation and prior to exposure to MV. In the porcine ARDS model, we utilized Yucatan minipigs receiving either IV LPS to induce septic shock, or both IT- and IV-delivered LPS to induce the pneumonia/septic shock/ARDS. Animals were intubated and connected to high Vt mechanical ventilation for 12 hr. Animals received the eNAMPT ALT-100 mAb IV at either 2 hr or 6 hr after initiation of septic shock and VILI. Animals were monitored continuously for 12 hr. Chest ultrasound and chest X-ray images were captured at time zero, 2 hr, and 12 hr after the start of LPS/MV exposure. BAL fluid, blood, urine, lung, and kidney tissues were collected at the end of study. Results. Compared to sepsis/ARDS-exposed, PBS-treated animals, - rats and pigs treated with the eNAMPT-neutralizing ALT-100 mAb (0.4 mg/kg, 2 hr or 6 hr after injury initiation) demonstrated significantly diminished severity of lung injury (histology, BAL PMNs, plasma cytokines), and reduced biochemical/genomic evidence of NF-kB/MAP kinase/cytokine receptor signaling, and AKI (histology, plasma lipocalin). ALT-100 mAb treatment effectively preserved lung fluid balance in pigs reflected by reduced BAL protein/tissue albumin levels, lung wet/dry tissue weight ratios, ultrasound-derived B lines, and chest radiograph opacities. ALT-100 treatment also decreased lung/renal injury indices in LPS/VILI-exposed rats and pigs when delivered 2 hr or 6 hr after injury initiation. Conclusions. These studies indicate that delivery of the eNAMPT-neutralizing ALT-100 mAb, even at a delayed time point after initial injury, directly mitigates the serious unmet need for novel ARDS therapeutics. The ALT-100 mAb reduced inflammatory lung injury, preserved lung fluid balance, and reduced multi-organ dysfunction. Moreover, the porcine preclinical ARDS model proved to be a robust tool to assess ALT-100 mAb efficacy and the therapeutic potential of other ARDS therapeutic candidates. Chest ultrasound and chest X-ray images may provide simple and inexpensive methods to longitudinally assess lung fluid imbalance and surrogate responses to ARDS therapeutics.