Pretreatment with perfluorohexane vapor attenuates fMLP-induced lung injury in isolated perfused rabbit lungs

The role of FPR2-mediated ferroptosis in formyl peptide-induced acute lung injury against endothelial barrier damage and protective effect of the mitochondria-derived peptide MOTS-c

BACKGROUND

Acute lung injury (ALI) has garnered significant attention in the field of respiratory and critical care due to its high mortality and morbidity, and limited treatment options. The role of the endothelial barrier in the development of ALI is crucial. Several bacterial pathogenic factors, including the bacteria-derived formyl peptide (fMLP), have been implicated in damaging the endothelial barrier and initiating ALI. However, the mechanism by which fMLP causes ALI remains unclear. In this study, we aim to explore the mechanisms of ALI caused by fMLP and evaluate the protective effects of MOTS-c, a mitochondrial-derived peptide.

METHODS

We established a rat model of ALI and a human pulmonary microvascular endothelial cell (HPMVEC) model of ALI by treatment with fMLP. In vivo experiments involved lung histopathology assays, assessments of inflammatory and oxidative stress factors, and measurements of ferroptosis-related proteins and barrier proteins to evaluate the severity of fMLP-induced ALI and the type of tissue damage in rats. In vitro experiments included evaluations of fMLP-induced damage on HPMVEC using cell activity assays, assessments of inflammatory and oxidative stress factors, measurements of ferroptosis-related proteins, endothelial barrier function assays, and examination of the key role of FPR2 in fMLP-induced ALI. We also assessed the protective effect of MOTS-c and investigated its mechanism on the fMLP-induced ALI in vivo and in vitro.

RESULTS

Results from both in vitro and in vivo experiments demonstrate that fMLP promotes the expression of inflammatory and oxidative stress factors, activates ferroptosis and disrupts the vascular endothelial barrier, ultimately contributing to the development and progression of ALI. Mechanistically, ferroptosis mediated by FPR2 plays a key role in fMLP-induced injury, and the Nrf2 and MAPK pathways are involved in this process. Knockdown of FPR2 and inhibition of ferroptosis can attenuate ALI induced by fMLP. Moreover, MOTS-c could protect the vascular endothelial barrier function by inhibiting ferroptosis and suppressing the expression of inflammatory and oxidative stress factors through Nrf2 and MAPK pathways, thereby alleviating fMLP-induced ALI.

CONCLUSION

Overall, fMLP disrupts the vascular endothelial barrier through FPR2-mediated ferroptosis, leading to the development and progression of ALI. MOTS-c demonstrates potential as a protective treatment against ALI by alleviating the damage induced by fMLP.

Use of nonhuman primates in obstructive lung disease research - is it required?

In times of increasing costs for health insurances, obstructive lung diseases are a burden for both the patients and the economy. Pulmonary symptoms of asthma and chronic obstructive pulmonary disease (COPD) are similar; nevertheless, the diseases differ in pathophysiology and therapeutic approaches. Novel therapeutics are continuously developed, and nonhuman primates (NHPs) provide valuable models for investigating novel biologicals regarding efficacy and safety.

This review discusses the role of nonhuman primate models for drug development in asthma and COPD and investigates whether alternative methods are able to prevent animal experiments.

Formyl peptide receptor modulators: a patent review and potential applications for inflammatory diseases (2012-2015)

INTRODUCTION

The activation of leukocytes and the subsequent immune cascade play an essential role in sterile and infectious inflammation. Dysregulation of these immune responses or excess leukocyte activation can induce tissue damage, organ dysfunction and mortality. Formyl peptide receptors (FPRs) are functionally diverse pattern recognition receptors responsible for recognizing different endogenous damage-associated molecular patterns or exogenous pathogen-associated molecular patterns. FPRs mediate leukocyte activation during inflammation. FPR1 antagonists and FPR2 agonists have demonstrated significant anti-inflammatory effects based on in vitro and in vivo studies. An increasing number of synthesized compounds targeting FPRs, especially potential FPR1 antagonists and FPR2 agonists, have been disclosed in patents. Areas covered: This article summarizes the current pharmacology patents related to FPR family modulators and their therapeutic indications based on a review of patent applications disclosed between 2012 and 2015. Expert opinion: In this review, FPR1 modulators comprise β-1,3-glucan synthase inhibitors containing an FPR ligand moiety, template-fixed peptidomimetics, cyclosporin H, and dipeptide derivatives. FPR2 modulators include phenylurea, bridged spiro[2.4]heptane ester, naphthalene, aminotriazole, polycyclic pyrrolidine-2,5-dione, imidazolidine-2,4-dione, (2-ureidoacetamido)alkyl, amide, oxazolyl-methylether, oxazole, thiazole, and crystalline potassium salt derivatives. These compounds have potential applications for human conditions such as inflammatory lung diseases, ischemia-reperfusion injury, sepsis, inflammatory bowel disease, and wound healing. FPRs are emerging as important targets for treating leukocyte-dominant inflammation.

In vitro, in vivo and ex vivo models for studying particle deposition and drug absorption of inhaled pharmaceuticals

Delivery of therapeutic agents via the pulmonary route has gained significant attention over the past few decades because this route of administration offers multiple advantages over traditional routes that include localized action, non-invasive nature and favorable lung-to-plasma ratio. However, assessment of post administration behavior of inhaled pharmaceuticals-such as deposition of particles over the respiratory airways, interaction with the respiratory fluid and movement across the air-blood barrier-is challenging because the lung is a very complex organs that is composed of airways with thousands of bifurcations with variable diameters. Thus, much effort has been put forward to develop models that mimic human lungs and allow evaluation of various pharmaceutical and physiological factors that influence the deposition and absorption profiles of inhaled formulations. In this review, we sought to discuss in vitro, in vivo and ex vivo models that have been extensively used to study the behaviors of airborne particles in the lungs and determine the absorption of drugs after pulmonary administration. We have provided a summary of lung cast models, cascade impactors, noninvasive imaging, intact animals, cell culture and isolated perfused lung models as tools to evaluate the distribution and absorption of inhaled particles. We have also outlined the limitations of currently used models and proposed future studies to enhance the reproducibility of these models.

Aerosolized semifluorinated alkanes as excipients are suitable for inhalative drug delivery--a pilot study

Semifluorinated alkanes (SFAs) have been described as potential excipients for pulmonary drug delivery, but proof of their efficacy is still lacking. We tested whether SFA formulations with the test drug ibuprofen can be nebulised and evaluated their pharmacokinetics. Physico-chemical properties of five different ibuprofen formulations were evaluated: an aqueous solution (H2O), two different SFAs (perfluorohexyloctane (F6H8), perfluorobutylpentane (F4H5)) with and without ethanol (SFA/EtOH). Nebulisation was performed with a jet catheter system. Inhalative characteristics were evaluated by laser diffraction. A confirmative animal study with an inhalative single-dose (6 mg/kg) of ibuprofen with each formulation was performed in anaesthetised healthy rabbits. Plasma samples at defined time points and lung tissue harvested after the 6-h study period were analyzed by HPLC-MS/MS. Pharmacokinetics were calculated using a non-compartment model. All formulations were nebulisable. No differences in aerodynamic diameters (MMAD) were detected between SFA and SFA/EtOH. The ibuprofen plasma concentration-time curve (AUC) was highest with F4H5/EtOH. In contrast, F6H8/EtOH had the highest deposition of ibuprofen into lung tissue but the lowest AUC. All tested SFA and SFA/EtOH formulations are suitable for inhalation. F4H5/EtOH formulations might be used for rapid systemic availability of drugs. F6H8/EtOH showed intrapulmonary deposition of the test drug.