In order to mount an appropriate immune response to infection, the macrophage must alter its metabolism by increasing aerobic glycolysis and concomitantly decreasing oxidative phosphorylation; a process known as the Warburg effect. Consequently, lactate, the end-product of glycolysis, accumulates in the extracellular environment. The subsequent effect of lactate on surrounding macrophages is poorly understood. Mycobacterium tuberculosis (Mtb), the causative organism of Tuberculosis (TB), is phagocytosed by macrophages in the airways. Mtb infected macrophages upregulate aerobic glycolysis and effector functions to try to kill the bacteria. Our lab has previously shown that human macrophages produce lactate in response to infection with Mtb. Although lactate has largely been considered a waste product of aerobic glycolysis, we hypothesised that the presence of extracellular lactate would impact subsequent immunometabolic responses and modulate macrophage function. We demonstrate that the presence of exogenous lactate has an immediate effect on the cellular metabolism of resting human macrophages; causing a decrease in extracellular acidification rate (ECAR; analogous to the rate of glycolysis) and an increase in the oxygen consumption rate (OCR; analogous to oxidative phosphorylation). When lactate-treated macrophages were stimulated with Mtb or LPS, glycolysis proceeds to increase immediately upon stimulation but oxidative phosphorylation remains stable compared with untreated cells that display a decrease in OCR. This resulted in a significantly reduced ECAR/OCR ratio early in response to stimulation. Since altered metabolism is intrinsically linked to macrophage function, we examined the effect of lactate on macrophage cytokine production and ability to kill Mtb. Lactate significantly reduced the concentrations of TNF and IL-1β produced by human macrophages in response to Mtb but did not alter IL-10 and IL-6 production. In addition, lactate significantly improved bacillary clearance in human macrophages infected with Mtb, through a mechanism that is, at least in part, mediated by promoting autophagy. These data indicate that lactate, the product of glycolysis, has a negative feedback effect on macrophages resulting in an attenuated glycolytic shift upon subsequent stimulation and reduced pro-inflammatory cytokine production. Interestingly, this pro-resolution effect of lactate is associated with increased capacity to kill Mtb.
A 58‐year old lady under active follow‐up with the respiratory services at our institution for bronchiectasis secondary to hypogammaglobulinaemia presented with hoarseness and haemoptysis. She was also receiving rituximab maintenance therapy for follicular lymphoma. Bronchoscopy demonstrated vesicular lesions on her vocal cords and trachea, confirmed as herpes simplex virus (HSV) on cytological analysis of brushings. She responded well to intravenous valacyclovir. Rituximab is increasingly utilised in the treatment of haematological and auto‐immune disorders. This case highlights the potential of this drug to potentiate susceptibility to infection in an already immunocompromised individual.
Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive fibrosing interstitial lung disease that occurs predominantly in the older population. There is increasing incidence and prevalence in IPF globally. The emergence of anti-fibrotic therapies in the last decade have improved patient survival though a cure is yet to be developed. In this review article, we aim to summarize the existing and novel pharmacotherapies for the treatment of IPF (excluding treatments for acute exacerbations), focusing on the current knowledge on the pathophysiology of the disease, mechanism of action of the drugs, and clinical trials.
CNSS. It is an ancient human habit to give something a name and then feel master of it. (Genesis 2-19: Now the LORD God had formed out of the ground all the wild animals and all the birds in the sky. He brought them to the man to see what he would name them; and whatever the man called each living creature, that was its name.) All the attention for sepsis may have led to framing in the direction of infection 4,5 ; however, although not consistent, there are differences found between the negative and positive cohort involving comorbidity, severity of illness, and outcome. 1,3 This suggests that the etiology also might be different and not solely related to undetected infection. In fact, we do not know the etiology of CNSS. The unjustified feeling of confidence because we think we know what we are dealing with might lead to diagnostic and research slackness.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.