ABSTRACT
Disrupted sleep, including daytime hypersomnolence, is a core symptom reported by primary brain tumor patients and often manifests after radiotherapy. The biological mechanisms driving the onset of sleep disturbances after cranial radiation remains unclear but may result from treatment-induced injury to neural circuits controlling sleep behavior, both circadian and homeostatic. Here, we develop a mouse model of cranial radiation-induced hypersomnolence which recapitulates the human experience. Additionally, we used the model to explore the impact of radiation on the brain. We demonstrated that the DNA damage response following radiation varies across the brain, with homeostatic sleep and cognitive regions expressing higher levels of γH2AX, a marker of DNA damage, than the circadian suprachiasmatic nucleus (SCN). These findings were supported by in vitro studies comparing radiation effects in SCN and cortical astrocytes. Moreover, in our mouse model, MRI identified structural effects in cognitive and homeostatic sleep regions two-months post-treatment. While the findings are preliminary, they suggest that homeostatic sleep and cognitive circuits are vulnerable to radiation and these findings may be relevant to optimizing treatment plans for patients.
Subject(s)
Circadian Rhythm , Disorders of Excessive Somnolence , Animals , Brain , Circadian Rhythm/physiology , Disease Models, Animal , Mice , Sleep/physiology , Suprachiasmatic Nucleus/physiologyABSTRACT
Background: Patients with primary brain tumors (PBT) face significant mobility issues related to their disease and/or treatment. Here, the authors describe the preliminary utility and feasibility of two established mobility measures, the Timed-Up-and-Go (TUG) and Five-Times Sit-to-Stand (TSS) tests, in quickly and objectively assessing the mobility status of PBT patients at a single institution's neuro-oncology clinic. Methods: Adult patients undergoing routine PBT care completed the TUG/TSS tests and MD Anderson Symptom Inventory-Brain Tumor module (MDASI-BT), which assessed symptom burden and interference with daily life, during clinic visits over a 6-month period. Research staff assessed feasibility metrics, including test completion times/rates, and collected demographic, clinical, and treatment data. Mann-Whitney tests, Kruskal-Wallis tests, and Spearman's rho correlations were used to interrogate relationships between TUG/TSS test completion times and patient characteristics. Results: The study cohort included 66 PBT patients, 59% male, with a median age of 47 years (range: 20-77). TUG/TSS tests were completed by 62 (94%) patients. Older patients (P < .001) and those who were newly diagnosed (P = .024), on corticosteroids (P = .025), or had poor (≤80) KPS (P < .01) took longer to complete the TUG/TSS tests. Worse activity-related (work, activity, and walking) interference was associated with longer TUG/TSS test completion times (P < .001). Conclusions: The TUG/TSS tests are feasible for use among PBT patients and may aid in clinical care. Older age, being newly diagnosed, using corticosteroids, poor (≤80) KPS, and high activity-related interference were associated with significant mobility impairment, highlighting the tests' potential clinical utility. Future investigations are warranted to longitudinally explore feasibility and utility in other practice and disease settings.
ABSTRACT
Circadian clock genes have been linked to clinical outcomes in cancer, including gliomas. However, these studies have not accounted for established markers that predict the prognosis, including mutations in Isocitrate Dehydrogenase (IDH), which characterize the majority of lower-grade gliomas and secondary high-grade gliomas. To demonstrate the connection between circadian clock genes and glioma outcomes while accounting for the IDH mutational status, we analyzed multiple publicly available gene expression datasets. The unsupervised clustering of 13 clock gene transcriptomic signatures from The Cancer Genome Atlas showed distinct molecular subtypes representing different disease states and showed the differential prognosis of these groups by a Kaplan-Meier analysis. Further analyses of these groups showed that a low period (PER) gene expression was associated with the negative prognosis and enrichment of the immune signaling pathways. These findings prompted the exploration of the relationship between the microenvironment and clock genes in additional datasets. Circadian clock gene expression was found to be differentially expressed across the anatomical tumor location and cell type. Thus, the circadian clock expression is a potential predictive biomarker in glioma, and further mechanistic studies to elucidate the connections between the circadian clock and microenvironment are warranted.
ABSTRACT
Age plays a critical role in disease development and tolerance to cancer treatment, often leading to an increased risk of developing negative symptoms including sleep disturbances. Circadian rhythms and sleep become disrupted as organisms age. In this study, we explored the behavioral alterations in sleep, circadian rhythms, and masking using a novel video system and interrogate the long-term impact of age-based changes in the non-image forming visual pathway on brain anatomy. We demonstrated the feasibility and utility of the novel system and establish that older mice have disruptions in sleep, circadian rhythms, and masking behaviors that were associated with major negative volume alterations in the non-imaging forming visual system, critical for the induction and rhythmic expression of sleep. These results provide important insights into a mechanism, showing brain atrophy is linked to age in distinct non-image forming visual regions, which may predispose older individuals to developing circadian and sleep dysfunction when further challenged by disease or treatment.
