Activation of the Adipose Tissue NLRP3 Inflammasome Pathway in Cancer Cachexia

The Molecular Mechanisms and Treatment of Cancer-Related Cachexia

Cancer cachexia is a multifactorial syndrome characterized by persistent skeletal muscle loss, with or without fat loss, which cannot be completely reversed by traditional nutritional support and leads to impaired organ function. Cachexia seriously reduces the quality of life of (QOL) patients, affects the therapeutic effect against cancers, increases the incidence of complications, and is an important cause of death for patients with advanced cancers. To date, no effective medical intervention has completely reversed cachexia, and no medication has been agreed upon. Here, we describe recent advances in the diagnosis, molecular mechanism and treatment of cancer-related cachexia.

Immune System Disorder and Cancer-Associated Cachexia

Cancer-associated cachexia (CAC) is a debilitating condition marked by muscle and fat loss, that is unresponsive to nutritional support and contributes significantly to morbidity and mortality in patients with cancer. Immune dysfunction, driven by cytokine imbalance, contributes to CAC progression. This review explores the potential relationship between CAC and anti-cancer immune response in pre-clinical and clinical studies. Pre-clinical studies showcase the involvement of cytokines like IL-1β, IL-6, IL-8, IFN-γ, TNF-α, and TGF-β, in CAC. IL-6 and TNF-α, interacting with muscle and adipose tissues, induce wasting through JAK/STAT and NF-κB pathways. Myeloid-derived suppressor cells (MDSCs) exacerbate CAC by promoting inflammation. Clinical studies confirm elevated pro-inflammatory cytokines (IL-6, IL-8, TNFα) and immune markers like the neutrophil-to-lymphocyte ratio (NLR) in patients with CAC. Thus, immunomodulatory mechanisms involved in CAC may impact the anti-neoplastic immune response. Inhibiting CAC mechanisms could enhance anti-cancer therapies, notably immunotherapy. R-ketorolac, a new immunomodulator, reversed the weight loss and increased survival in mice. Combining these agents with immunotherapy may benefit patients with cancer experiencing CAC. Further research is vital to understand the complex interplay between tumor-induced immune dysregulation and CAC during immunotherapy.

Immunoregulation in cancer-associated cachexia

BACKGROUND

Cancer-associated cachexia is a multi-organ disorder associated with progressive weight loss due to a variable combination of anorexia, systemic inflammation and excessive energy wasting. Considering the importance of immunoregulation in cachexia, it still lacks a complete understanding of the immunological mechanisms in cachectic progression.

AIM OF REVIEW

Our aim here is to describe the complex immunoregulatory system in cachexia. We summarize the effects and translational potential of the immune system on the development of cancer-associated cachexia and we attempt to conclude with thoughts on precise and integrated therapeutic strategies under the complex immunological context of cachexia.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review is focused on three main key concepts. First, we highlight the inflammatory factors and additional mediators that have been identified to modulate this syndrome. Second, we decipher the potential role of immune checkpoints in tissue wasting. Third, we discuss the multilayered insights in cachexia through the immunometabolic axis, immune-gut axis and immune-nerve axis.

Ectopic and visceral fat deposition in aging, obesity, and idiopathic pulmonary fibrosis: an interconnected role

Idiopathic pulmonary fibrosis (IPF) is considered an age-related disease. Age-related changes, along with other factors such as obesity, hormonal imbalances, and various metabolic disorders, lead to ectopic fat deposition (EFD). This accumulation of fat outside of its normal storage sites is associated with detrimental effects such as lipotoxicity, oxidative stress, inflammation, and insulin resistance. This narrative review provides an overview of the connection between ectopic and visceral fat deposition in aging, obesity, and IPF. It also elucidates the mechanism by which ectopic fat deposition in the airways and lungs, pericardium, skeletal muscles, and pancreas contributes to lung injury and fibrosis in patients with IPF, directly or indirectly. Moreover, the review discusses the impact of EFD on the severity of the disease, quality of life, presence of comorbidities, and overall prognosis in IPF patients. The review provides detailed information on recent research regarding representative lipid-lowering drugs, hypoglycemic drugs, and lipid-targeting drugs in animal experiments and clinical studies. This may offer new therapeutic directions for patients with IPF.

Role of CD14 in human disease

The cell surface antigen CD14 is primarily understood to act as a co-receptor for toll-like receptors (TLRs) to activate innate immunity responses to pathogens and tissue injury in macrophages and monocytes. However, roles for CD14 are increasingly being uncovered in disease responses in epithelial and endothelial cells. Consistent with these broader functions, CD14 expression is altered in a variety of non-immune cell types in response to a several of disease states. Moreover, soluble CD14 activated by factors from both pathogens and tissue damage may initiate signalling in a variety of non-immune cells. This review examined the current understanding CD14 in innate immunity as well as its potential functions in nonimmune cells and associated human diseases.