Involvement of Ghrelin Dynamics in Stress-Induced Eating Disorder: Effects of Sex and Aging

Central neural mechanisms of cancer cachexia

PURPOSE OF REVIEW

Cachexia is a devasting syndrome which impacts a large number of patients with cancer. This review aims to provide a comprehensive overview of the central mechanisms of cancer cachexia. In particular, it focuses on the role of the central nervous system (CNS), the melanocortin system, circulating hormones and molecules which are produced by and act on the CNS and the psychological symptoms of cancer cachexia.

RECENT FINDINGS

A growing body of evidence suggests that a central mechanism of action underpins this multi-system disorder. Recent research has focused on the role of neuroinflammation that drives the sickness behaviour seen in cancer cachexia, with emphasis on the role of the hypothalamus. Melanocortin receptor antagonists are showing promise in preclinical studies. There are also new pharmacological developments to overcome the short half-life of ghrelin. GDF-15 has been identified as a core target and trials of compounds that interfere with its signalling or its central receptor are underway.

SUMMARY

Understanding the central mechanisms of cancer cachexia is pivotal for enhancing treatment outcomes in patients. While emerging pharmacological interventions targeting these pathways have shown promise, further research is essential.

Emerging Relevance of Ghrelin in Programmed Cell Death and Its Application in Diseases

Ghrelin, comprising 28 amino acids, was initially discovered as a hormone that promotes growth hormones. The original focus was on the effects of ghrelin on controlling hunger and satiation. As the research further develops, the research scope of ghrelin has expanded to a wide range of systems and diseases. Nevertheless, the specific mechanisms remain incompletely understood. In recent years, substantial studies have demonstrated that ghrelin has anti-inflammatory, antioxidant, antiapoptotic, and other effects, which could affect the signaling pathways of various kinds of programmed cell death (PCD) in treating diseases. However, the regulatory mechanisms underlying the function of ghrelin in different kinds of PCD have not been thoroughly illuminated. This review describes the relationship between ghrelin and four kinds of PCD (apoptosis, necroptosis, autophagy, and pyroptosis) and then introduces the clinical applications based on the different features of ghrelin.

Clinical correlates and prognostic impact of binge-eating symptoms in major depressive disorder

Binge-eating (BE) symptoms are relatively common in major depressive disorder (MDD), but their prognostic role is not fully understood. This study compared two groups of patients with MDD experiencing or not BE symptoms to ascertain differences in terms of clinical manifestations, presence of bipolar features, and antidepressant treatment outcomes. The study involved 482 outpatients collected within the Combining Medications to Enhance Depression Outcomes (CO-MED) trial, who were assessed with scales for depressive and hypomanic symptomatology, suicidality, comorbid mental disorders, and childhood traumas. BE symptoms were reported in 95 patients (20%). Patients with MDD experiencing BE symptoms were characterized by higher scores of negative self-outlook ( P = 0.0018), negative outlook of future ( P = 0.0014), irritability ( P = 0.0043), comorbid anxiety disorders (generalized anxiety disorder: P = 0.0006; panic disorder: P < 0.0001; social phobia: P < 0.0001), obsessive-compulsive disorder ( P = 0.0053), hypomanic symptoms (increased talkativeness: P = 0.0029; reduced need for sleep: P = 0.0171), and suicidality (suicidal propensity: P = 0.0013; suicidal risk: P = 0.0148; lifetime suicidal behavior: P = 0.0052). BE symptoms (OR = 2.02; 95% CI = 1.06-3.84) and depression severity (OR = 1.04; 95% CI = 1.00-1.08) were independently associated with lifetime attempted suicide. The presence of BE symptoms might indicate higher severity of depressive disorder. Suicidal risk is a major issue in these patients, whereas the association between BE and bipolar features needs further research.

Role of the Ghrelin System in Colorectal Cancer

The ghrelin system contains several components (e.g., ghrelin with growing number of alternative peptides, growth hormone secretagogue receptors (GHS-Rs), and ghrelin-O-acyl-transferase (GOAT) and participates in regulation of a number of key processes of gastrointestinal (GI) tract cancer progression, including cell proliferation, migration, invasion, apoptosis, inflammation, and angiogenesis. However, its exact role in promoting or inhibiting cancer progression is still unclear. Colorectal cancer (CRC) is one of the most common human malignancies worldwide. Molecular studies suggest an autocrine/paracrine mechanism for the secretion of ghrelin in colorectal carcinogenesis and its contribution to its initial stages. However, the signalling pathways of CRC development involving the ghrelin system are poorly understood. Potential mechanisms of colon carcinogenesis involving components of the ghrelin system were previously described in an animal model and in in vitro studies. However, the diagnostic–prognostic role of serum ghrelin concentrations, tissue expression, or genetic changes of this system in various stages of CRC progression remains an open case. Thus, the aim of this study is to discuss the role of the ghrelin system in colon carcinogenesis, diagnostics and CRC prognostics, as well as the results of studies on the use of ghrelin and its analogues in the therapy of CRC-related syndromes (e.g., cachexia and sarcopenia).