The role of mTOR signalling pathway in hypoxia-induced cognitive impairment

Natural products targeting macroautophagy signaling in hepatocellular carcinoma therapy: Recent evidence and perspectives

Hepatocellular carcinoma (HCC), presently the second leading cause of global cancer-related mortality, continues to pose significant challenges in the realm of medical oncology, impacting both clinical drug selection and mechanistic research. Recent investigations have unveiled autophagy-related signaling as a promising avenue for HCC treatment. A growing body of research has highlighted the pivotal role of autophagy-modulating natural products in inhibiting HCC progression. In this context, we provide a concise overview of the fundamental autophagy mechanism and delineate the involvement of autophagic signaling pathways in HCC development. Additionally, we review pertinent studies demonstrating how natural products regulate autophagy to mitigate HCC. Our findings indicate that natural products exhibit cytotoxic effects through the induction of excessive autophagy, simultaneously impeding HCC cell proliferation by autophagy inhibition, thereby depriving HCC cells of essential energy. These effects have been associated with various signaling pathways, including PI3K/AKT, MAPK, AMPK, Wnt/β-catenin, Beclin-1, and ferroautophagy. These results underscore the considerable therapeutic potential of natural products in HCC treatment. However, it is important to note that the present study did not establish definitive thresholds for autophagy induction or inhibition by natural products. Further research in this domain is imperative to gain comprehensive insights into the dual role of autophagy, equipping us with a better understanding of this double-edged sword in HCC management.

Neurotrophins in the Neuropathophysiology, Course, and Complications of Obstructive Sleep Apnea-A Narrative Review

Obstructive sleep apnea (OSA) is a disorder characterized by chronic intermittent hypoxia and sleep fragmentation due to recurring airway collapse during sleep. It is highly prevalent in modern societies, and due to its pleiotropic influence on the organism and numerous sequelae, it burdens patients and physicians. Neurotrophins (NTs), proteins that modulate the functioning and development of the central nervous system, such as brain-derived neurotrophic factor (BDNF), have been associated with OSA, primarily due to their probable involvement in offsetting the decline in cognitive functions which accompanies OSA. However, NTs influence multiple aspects of biological functioning, such as immunity. Thus, extensive evaluation of their role in OSA might enlighten the mechanism behind some of its elusive features, such as the increased risk of developing an immune-mediated disease or the association of OSA with cardiovascular diseases. In this review, we examine the interactions between NTs and OSA and discuss their contribution to OSA pathophysiology, complications, as well as comorbidities.

A bibliometric analysis of the studies in high-altitude induced sleep disturbances and cognitive impairment research

Background: The two main symptoms at high altitude, sleep abnormalities and cognitive impairments, interact with each other. These two dysfunctions are also closely related to systemic multisystem diseases, including cerebrovascular diseases, psychiatric disorders, and immune regulatory diseases. Purpose: To systematically analyze and visualize research on sleep disturbances and cognitive impairment at high altitudes using a bibliometrics method, and to determine future research directions by analyzing research trends and the latest hotspots. Methods: Publications from 1990 to 2022 on sleep disturbances and cognitive impairment at high altitudes were retrieved from the Web of Science. Using the R Bibliometrix software and Microsoft Excel, all data were examined statistically and qualitatively. For network visualization, the data were later exported into VOSviewer 1.6.17 and CiteSpace 6.1.R6. Results: A total of 487 articles in this area were published from 1990 to 2022. In this period, there was an overall increase in the number of publications. The United States has shown considerable importance in this sector. Bloch Konrad E was the most prolific and valuable author. The most prolific journal was High Altitude Medicine & Biology, and it has been the first choice for publishing in this field in recent years. Analysis of keyword co-occurrences suggested that research interest in the clinical manifestations of sleep disturbances and cognitive impairment caused by altitude hypoxia was mainly focused on "acute mountain-sickness," "insomnia," "apnea syndrome," "depression," "anxiety," "Cheyne-strokes respiration," and "pulmonary hypertension." The mechanisms of disease development related to "oxidative stress," "inflammation," "hippocampus," "prefrontal cortex," "neurodegeneration," and "spatial memory" in the brain have been the focus of recent research. According to burst detection analysis, "mood" and "memory impairment," as terms with high strength, are expected to remain hot topics in the coming years. High-altitude-induced pulmonary hypertension is also in the emerging stage of research, and the treatments will continue to receive attention in the future. Conclusion: More attention is being focused on sleep disturbances and cognitive impairment at high altitudes. This work will serve as a useful reference for the clinical development of treatments for sleep disturbances and cognitive impairment induced by hypobaric hypoxia at high altitudes.

BDNF and proBDNF Serum Protein Levels in Obstructive Sleep Apnea Patients and Their Involvement in Insomnia and Depression Symptoms

Introduction: Obstructive sleep apnea (OSA) is a disorder that, apart from somatic sequelae, increases the risk of developing psychiatric conditions. Brain-derived neurotrophic factor (BDNF) signaling pathway is involved in the pathophysiology of depression and insomnia. Therefore, the study aimed to investigate differences in concentrations of BDNF and proBDNF in patients with OSA and healthy individuals, to evaluate diurnal changes of these proteins, and to assess the correlations with psychiatric symptoms. Methods: Sixty individuals following polysomnography (PSG) were divided into two groups based on the apnea-hypopnea index (AHI): OSA patients (AHI ≥ 30; n = 30) and control group (AHI < 5; n = 30). Participants filled out questionnaires: Beck Depression Inventory (BDI), Athens Insomnia Scale (AIS), and Pittsburgh Sleep Quality Index (PSQI). Peripheral blood was collected before and after PSG. Protein concentrations were measured using ELISA. OSA group was divided into subgroups: AIS (−)/AIS (+) (AIS > 5), PSQI (−)/PSQI (+) (PSQI > 5), and BDI (−)/BDI (+) (BDI > 19). Results: No differences in BDNF and proBDNF protein levels were observed between OSA and the control groups. However, BDNF and proBDNF evening protein concentrations were higher in the AIS (+) and PSQI (+) groups (p < 0.001 for all). The BDI (+) group was characterized by lower morning levels of both proteins (p = 0.047 and p = 0.003, respectively). Conclusions: BDNF signaling pathway might be involved in the pathophysiology of depression and insomnia in patients with OSA. BDNF and proBDNF protein levels might be useful in defining OSA phenotypes.

Hypoxia, Oxidative Stress, and Inflammation: Three Faces of Neurodegenerative Diseases

The cerebral hypoxia-ischemia can induce a wide spectrum of biologic responses that include depolarization, excitotoxicity, oxidative stress, inflammation, and apoptosis, and result in neurodegeneration. Several adaptive and survival endogenous mechanisms can also be activated giving an opportunity for the affected cells to remain alive, waiting for helper signals that avoid apoptosis. These signals appear to help cells, depending on intensity, chronicity, and proximity to the central hypoxic area of the affected tissue. These mechanisms are present not only in a large list of brain pathologies affecting commonly older individuals, but also in other pathologies such as refractory epilepsies, encephalopathies, or brain trauma, where neurodegenerative features such as cognitive and/or motor deficits sequelae can be developed. The hypoxia inducible factor 1α (HIF-1α) is a master transcription factor driving a wide spectrum cellular response. HIF-1α may induce erythropoietin (EPO) receptor overexpression, which provides the therapeutic opportunity to administer pharmacological doses of EPO to rescue and/or repair affected brain tissue. Intranasal administration of EPO combined with other antioxidant and anti-inflammatory compounds could become an effective therapeutic alternative, to avoid and/or slow down neurodegenerative deterioration without producing adverse peripheral effects.