The American journal of pathology
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Idiopathic pulmonary fibrosis (IPF) is characterized by excessive scarring of the lung parenchyma, resulting in a steady decline of lung function and ultimately respiratory failure. The disease course of IPF is extremely variable, with some patients exhibiting stability of symptoms for prolonged periods of time, whereas others exhibit rapid progression and loss of lung function. Viral infections have been implicated in IPF and linked to disease severity; however, whether they directly contribute to progression is unclear. ⋯ Results showed induction of TLR9 expression by TGF-β in lung myofibroblasts and a distinct profibrotic myofibroblast phenotype driven by stimulation with the TLR9 agonist, CpG-DNA. Chronic TLR9 stimulation resulted in stably differentiated α-smooth muscle actin(+)/platelet-derived growth factor receptor α(+)/CD44(+)/matrix metalloproteinase-14(+)/matrix metalloproteinase-2(+) myofibroblasts, which secrete inflammatory cytokines, invade Matrigel toward platelet-derived growth factor, and resist hypoxia-induced apoptosis. These results suggest a mechanism by which TGF-β and TLR9 responses in myofibroblasts collaborate to drive rapid progression of IPF.
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Small animal models of chronic obstructive pulmonary disease (COPD) have several limitations for identifying new therapeutic targets and biomarkers for human COPD. These include a pulmonary anatomy that differs from humans, the limited airway pathologies and lymphoid aggregates that develop in smoke-exposed mice, and the challenges associated with serial biological sampling. Thus, we assessed the utility of cigarette smoke (CS)-exposed cynomolgus macaque as a nonhuman primate (NHP) large animal model of COPD. ⋯ Although CS-exposed NHPs did not develop emphysema over the study time, they exhibited pathologies that precede emphysema development, including increases in the following: i) matrix metalloproteinase-9 and proinflammatory mediator levels in bronchoalveolar lavage fluid, ii) lung parenchymal leukocyte counts and lymphoid aggregates, iii) lung oxidative stress levels, and iv) alveolar septal cell apoptosis. CS-exposed NHPs can be used as a model of airway disease occurring in COPD patients. Unlike rodents, NHPs can safely undergo longitudinal sampling, which could be useful for assessing novel biomarkers or therapeutics for COPD.
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Visceral fat necrosis has been associated with severe acute pancreatitis (SAP) for over 100 years; however, its pathogenesis and role in SAP outcomes are poorly understood. Based on recent work suggesting that pancreatic fat lipolysis plays an important role in SAP, we evaluated the role of pancreatic lipases in SAP-associated visceral fat necrosis, the inflammatory response, local injury, and outcomes of acute pancreatitis (AP). For this, cerulein pancreatitis was induced in lean and obese mice, alone or with the lipase inhibitor orlistat and parameters of AP induction (serum amylase and lipase), fat necrosis, pancreatic necrosis, and multisystem organ failure, and inflammatory response were assessed. ⋯ Lipase inhibition reduced fat necrosis, UFAs, organ failure, and mortality but not the parameters of AP induction. Pancreatic lipase expression increased lipolysis in 3T3-L1 cells. We conclude that UFAs generated via lipolysis of visceral fat by pancreatic lipases convert mild AP to SAP independent of pancreatic necrosis and the inflammatory response.