Effects of sleep deprivation on cognitive functions

Unlocking Mysteries: Exploring the Dynamic Interplay among Sleep, the Immune System, and Curcumin in Contemporary Research

The scientific disciplines encompassing sleep, the immune system, and curcumin have garnered considerable interest due to their interconnectedness and potential implications for human health. Sleep is a crucial factor in maintaining optimal immune function, as it facilitates the release of cytokines, which are signaling molecules responsible for regulating immune responses. On the contrary, sleep deprivation has the potential of inhibiting immune function, thereby heightening the susceptibility to infection and disease. Curcumin, a naturally occurring polyphenol derived from the turmeric plant, has been observed to possess immunomodulatory characteristics through its ability to modulate the equilibrium between pro- and anti-inflammatory cytokines. It is worth noting that there is evidence suggesting that curcumin supplementation could enhance the quality of sleep. Scientific studies have indicated that curcumin supplementation has been associated with an increase in the duration of sleep and a decrease in wakefulness among individuals who are in good health. Additionally, curcumin supplementation has been found to enhance sleep quality and alleviate symptoms of depression in individuals diagnosed with major depressive disorder. The intricate interplay among sleep, the immune system, and curcumin is multifaceted, and scientific investigations indicate that curcumin may serve as a beneficial dietary adjunct to enhance immune function and optimize sleep quality. Nevertheless, additional investigation is required to fully comprehend the mechanisms through which curcumin alters the immune system and enhances sleep, as well as to ascertain the most effective dose and timing of curcumin supplementation.

Role of IGF-1 in neuroinflammation and cognition deficits induced by sleep deprivation

Sleep deprivation negatively influences cognition, however, the regulatory mechanisms to counteract this effect have not been identified. IGF-1 has been shown to be anti-inflammatory and neuroprotective in CNS injury models. In this study, we determined the impact of IGF-1 on brain injury and inflammation while modeling sleep deprivation. We found that IGF-1 was downregulated in human peripheral blood and in mice subjected to sleep deprivation for 5 days, with reduced activation of the downstream PI3K/AKT/GSK-3β pathway in mice brains. In addition, we found reduced levels of the anti-apoptosis enzyme Bcl-2 and increased levels of pro-apoptosis enzyme Caspase-9 expression, together with increased pro-inflammatory factors. The administration of IGF-1 after sleep deprivation induced activation of the PI3K/AKT/GSK-3β pathway, reversed changes in Bcl-2, Caspase-9, and pro-inflammatory factors, and alleviated cognitive impairment. Notably, IGF-1 also induced activation of the PI3K/AKT/GSK-3β pathway, and displayed anti-apoptosis and anti-inflammatory properties under normal sleep conditions,while IGF-1 did not improve the cognition under normal sleep conditions. These results suggest that the IGF-1/PI3K/AKT/GSK-3β pathway is involved in the regulation of cognitive function after sleep deprivation through modulation of apoptosis and inflammatory response. IGF-1 could be a viable therapeutic target, though further investigation is required to better understand its role in sleep deprivation.

Concussive head injury exacerbates neuropathology of sleep deprivation: Superior neuroprotection by co-administration of TiO2-nanowired cerebrolysin, alpha-melanocyte-stimulating hormone, and mesenchymal stem cells

Sleep deprivation (SD) is common in military personnel engaged in combat operations leading to brain dysfunction. Military personnel during acute or chronic SD often prone to traumatic brain injury (TBI) indicating the possibility of further exacerbating brain pathology. Several lines of evidence suggest that in both TBI and SD alpha-melanocyte-stimulating hormone (α-MSH) and brain-derived neurotrophic factor (BDNF) levels decreases in plasma and brain. Thus, a possibility exists that exogenous supplement of α-MSH and/or BDNF induces neuroprotection in SD compounded with TBI. In addition, mesenchymal stem cells (MSCs) are very portent in inducing neuroprotection in TBI. We examined the effects of concussive head injury (CHI) in SD on brain pathology. Furthermore, possible neuroprotective effects of α-MSH, MSCs and neurotrophic factors treatment were explored in a rat model of SD and CHI. Rats subjected to 48h SD with CHI exhibited higher leakage of BBB to Evans blue and radioiodine compared to identical SD or CHI alone. Brain pathology was also exacerbated in SD with CHI group as compared to SD or CHI alone together with a significant reduction in α-MSH and BDNF levels in plasma and brain and enhanced level of tumor necrosis factor-alpha (TNF-α). Exogenous administration of α-MSH (250μg/kg) together with MSCs (1×10⁶) and cerebrolysin (a balanced composition of several neurotrophic factors and active peptide fragments) (5mL/kg) significantly induced neuroprotection in SD with CHI. Interestingly, TiO₂ nanowired delivery of α-MSH (100μg), MSCs, and cerebrolysin (2.5mL/kg) induced enhanced neuroprotection with higher levels of α-MSH and BDNF and decreased the TNF-α in SD with CHI. These observations are the first to show that TiO₂ nanowired administration of α-MSH, MSCs and cerebrolysin induces superior neuroprotection following SD in CHI, not reported earlier. The clinical significance of our findings in light of the current literature is discussed.

Physical activity and sleep problems in homeless adults

Background

For the estimated 554,000 homeless individuals on any given night in the United States, obtaining quality sleep is often challenging. This group is known to have multiple health disparities, potentially affected by sleep problems; therefore, identifying lifestyle factors–such as physical activity–that are associated with improving both quality and quantity of sleep has important implications for public health. Here, we examine associations of physical activity with subjective sleep problems within a large sample of homeless adults.

Methods

Participants were homeless adults recruited from Dallas and Oklahoma (N = 747; 66.1% men, M_age = 43.7±12.1). Participants self-reported insufficient sleep (number of days without sufficient rest/sleep in the last month; categorized as 0, 1–13, 14–29, or ≥30 days), sleep duration (over average 24 hours; categorized as ≤6 [short sleeper], 7–9 [optimal sleeper], or ≥10 hours [long sleeper]), and unintentional daytime sleep (number of days with unintentional sleep in the last month; categorized as 0 vs ≥30 days). Physical activity was assessed subjectively using the BRFSS Physical Activity Questionnaire. Regression analyses were performed to examine the associations between physical activity and sleep problems, controlling for age, sex, race, education, body mass, months homeless, at-risk drinking, self-rated health, serious mental illness, smoking status, and recruitment city.

Results

Failure to meet/exceed physical activity guidelines was associated with higher likelihood of being a long sleeper (OR = 2.64, 95% CI: 1.46, 4.78) but a lower likelihood of having ≥30 days of insufficient rest/sleep (OR = 0.52, 95% CI: 0.29, 0.93).

Conclusions

Findings suggest that physical activity promotion may hold promise for addressing the problem of too much sleep, but not other manifestations of sleep problems among this vulnerable group.

Inhibited Endogenous H2S Generation and Excessive Autophagy in Hippocampus Contribute to Sleep Deprivation-Induced Cognitive Impairment

Background and Aim: Sleep deprivation (SD) causes deficit of cognition, but the mechanisms remain to be fully established. Hydrogen sulfide (H₂S) plays an important role in the formation of cognition, while excessive and prolonged autophagy in hippocampus triggers cognitive disorder. In this work, we proposed that disturbances in hippocampal endogenous H₂S generation and autophagy might be involved in SD-induced cognitive impairment.

Methods: After treatment of adult male wistar rats with 72-h SD, the Y-maze test, object location test (OLT), novel object recognition test (NORT) and the Morris water maze (MWM) test were performed to determine the cognitive function. The autophagosome formation was observed with electron microscope. Generation of endogenous H₂S in the hippocampus of rats was detected using unisense H₂S microsensor method. The expressions of cystathionine-β-synthase (CBS), 3-mercaptopyruvate sulfurtransferase (3-MST), beclin-1, light chain LC3 II/LC3 I, and p62 in the hippocampus were assessed by western blotting.

Results: The Y-maze, OLT, NORT, and MWM test demonstrated that SD-exposed rats exhibited cognitive dysfunction. SD triggered the elevation of hippocampal autophagy as evidenced by enhancement of autophagosome, up-regulations of beclin-1 and LC3 II/LC3 I, and down-regulation of p62. Meanwhile, the generation of endogenous H₂S and the expressions of CBS and 3-MST (H₂S producing enzyme) in the hippocampus of SD-treated rats were reduced.

Conclusion: These results suggested that inhibition of endogenous H₂S generation and excessiveness of autophagy in hippocampus are involved in SD-induced cognitive impairment.

Orexin A attenuates the sleep-promoting effect of adenosine in the lateral hypothalamus of rats

Orexin neurons within the lateral hypothalamus play a crucial role in the promotion and maintenance of arousal. Studies have strongly suggested that orexin neurons are an important target in endogenous adenosine-regulated sleep homeostasis. Orexin A induces a robust increase in the firing activity of orexin neurons, while adenosine has an inhibitory effect. Whether the excitatory action of orexins in the lateral hypothalamus actually promotes wakefulness and reverses the sleep-producing effect of adenosine in vivo is less clear. In this study, electroencephalographic and electromyographic recordings were used to investigate the effects of orexin A and adenosine on sleep and wakefulness in rats. We found that microinjection of orexin A into the lateral hypothalamus increased wakefulness with a concomitant reduction of sleep during the first 3 h of post-injection recording, and this was completely blocked by a selective antagonist for orexin receptor 1, SB 334867. The enhancement of wakefulness also occurred after application of the excitatory neurotransmitter glutamate in the first 3 h post-injection. However, in the presence of the NMDA receptor antagonist APV, orexin A did not induce any change of sleep and wakefulness in the first 3 h. Further, exogenous application of adenosine into the lateral hypothalamus induced a marked increase of sleep in the first 3-h post-injection. No significant change in sleep and wakefulness was detected after adenosine application followed by orexin A administration into the same brain area. These findings suggest that the sleep-promoting action of adenosine can be reversed by orexin A applied to the lateral hypothalamus, perhaps by exciting glutamatergic input to orexin neurons via the action of orexin receptor 1.

Sleep duration and self-rated health: the national health interview survey 2008

BACKGROUND

Self-rated health (SRH) has been shown to consistently predict overall mortality and cardiovascular mortality in several population-based studies across the world. Similarly sleep duration have been found to be associated with cardiovascular disease (CVD) and mortality. However, relatively few studies have examined the association between sleep duration and SRH, and the results have not been consistent.

METHODS

We conducted a cross-sectional study of n = 20,663 National Health Interview Survey 2008 participants ≥ 18 years of age (56.2% women). Sleep duration was categorized as ≤ 5 h, 6 h, 7 h, 8 h, and ≥ 9 h. The main outcome interest was fair/poor SRH (n = 3043).

RESULTS

We found both short and long sleep duration to be independently associated with fair/poor SRH, independent of age, sex, race-ethnicity, smoking, alcohol intake, body mass index, physical activity, depression, diabetes mellitus, hypertension, and CVD. Compared with a sleep duration of 7 h (referent), the multivariate odds ratio (95% confidence interval) of fair/poor SRH was 2.29 (1.86-2.83), 1.68 (1.42-2.00), 1.38 (1.18-1.61), and 1.98 (1.63-2.40) for sleep duration ≤ 5, 6, 8, and ≥ 9 h. This association persisted in subgroup analyses by gender, race-ethnicity, and body mass index categories.

CONCLUSION

Compared with sleep duration of 7 h, there was a positive association between both shorter and longer sleep duration and fair/poor self-rated health in a representative sample of US adults.

Default network response to a working memory challenge after withdrawal of continuous positive airway pressure treatment for obstructive sleep apnea

Lower working memory performance and altered brain activity have been reported in studies of obstructive sleep apnea (OSA) patients. However, little is known about the effect of treatment of OSA on brain function, particularly effects on default network processing. We previously reported increased brain response to a working memory challenge in active regions and decreased response in relatively deactivated a priori regions of interest (ROIs) following withdrawal of continuous positive airway pressure (CPAP) treatment. This follow-up analysis was conducted to examine the effects of CPAP withdrawal on default network processing using empirically defined ROIs analyses (i.e., in ROIs exhibiting significant deactivation in the sample). Ten OSA patients performed a 2-Back working memory task during functional magnetic resonance imaging in two separate conditions, following regular CPAP use, and after two nights of CPAP withdrawal. Eleven clusters of significant 2-Back-related deactivation consistent with the default network were identified and further examined for CPAP withdrawal effects. Significant further deactivation relative to the treatment adherent baseline was observed in the majority of these ROIs during the withdrawal condition. The magnitude of deactivation during withdrawal was significantly associated with better working memory performance in the posterior cingulate and right postcentral gyrus, and greater sleepiness in the left and right medial frontal gyrus. Results suggest that default network functions are further suspended as a result of a shifting of attention towards a more difficult active task in the context of lowered attentional capacity related to sleepiness.