Muscle atrophy in aging and chronic diseases: is it sarcopenia or cachexia?

Cachexia and sarcopenia present several analogies in both the pathogenic mechanisms and the clinical picture. The loss of muscle mass and strength is a hallmark of these two clinical conditions. Although frequently overlapping and often indistinguishable, especially in old individuals, these two conditions should be considered distinct clinical entities. A prompt and accurate patient evaluation, guiding the physician through a proper differential diagnostic procedure and providing the best therapeutic options, is recommended. Given the several commonalities between cachexia and sarcopenia, it is likely that the therapeutic approaches may prove effective in both conditions. This review focuses on the most recent available literature and aims at providing physicians with the correct tools that are available to aid in diagnosing these two different entities that often clinically overlap. Currently available or proposed therapeutic strategies for pre-cachexia, cachexia and sarcopenia are also briefly described

The prostaglandin D2 receptor 2 pathway in asthma: a key player in airway inflammation

Abstract Asthma is characterised by chronic airway inflammation, airway obstruction and hyper-responsiveness. The inflammatory cascade in asthma comprises a complex interplay of genetic factors, the airway epithelium, and dysregulation of the immune response. Prostaglandin D2 (PGD2) is a lipid mediator, predominantly released from mast cells, but also by other immune cells such as TH2 cells and dendritic cells, which plays a significant role in the pathophysiology of asthma. PGD2 mainly exerts its biological functions via two G-protein-coupled receptors, the PGD2 receptor 1 (DP1) and 2 (DP2). The DP2 receptor is mainly expressed by the key cells involved in type 2 immune responses, including TH2 cells, type 2 innate lymphoid cells and eosinophils. The DP2 receptor pathway is a novel and important therapeutic target for asthma, because increased PGD2 production induces significant inflammatory cell chemotaxis and degranulation via its interaction with the DP2 receptor. This interaction has serious consequences in the pulmonary milieu, including the release of pro-inflammatory cytokines and harmful cationic proteases, leading to tissue remodelling, mucus production, structural damage, and compromised lung function. This review will discuss the importance of the DP2 receptor pathway and the current understanding of its role in asthma