A Multimodal Feature Fusion Framework for Sleep-Deprived Fatigue Detection to Prevent Accidents.

Sleep-deprived fatigued person is likely to commit more errors that may even prove to be fatal. Thus, it is necessary to recognize this fatigue. The novelty of the proposed research work for the detection of this fatigue is that it is nonintrusive and based on multimodal feature fusion. In the proposed methodology, fatigue is detected by obtaining features from four domains: visual images, thermal images, keystroke dynamics, and voice features. In the proposed methodology, the samples of a volunteer (subject) are obtained from all four domains for feature extraction, and empirical weights are assigned to the four different domains. Young, healthy volunteers (n = 60) between the age group of 20 to 30 years participated in the experimental study. Further, they abstained from the consumption of alcohol, caffeine, or other drugs impacting their sleep pattern during the study. Through this multimodal technique, appropriate weights are given to the features obtained from the four domains. The results are compared with k-nearest neighbors (kNN), support vector machines (SVM), random tree, random forest, and multilayer perceptron classifiers. The proposed nonintrusive technique has obtained an average detection accuracy of 93.33% in 3-fold cross-validation.

Hypobaric Hypoxia Induces Deficits in Adult Neurogenesis and Social Interaction via Cyclooxygenase-1/ EP1 Receptor Pathway Activating NLRP3 Inflammasome.

Low oxygen environments, like hypobaric hypoxia (HH), are common nodes in a number of diseases characterized by neuroinflammation, which is detrimental to the structural and functional aspects of hippocampal circuitry. Hypoxic conditions lead to elevation of inflammasome-mediated inflammation that may contribute to cognitive deficits. However, a systematic investigation of the impact of inflammasome-mediated neuroinflammation on the components of neurogenic niche during HH remains to be elusive. Cerebral hypoxia was induced in adult male Sprague Dawley rats via decreasing partial pressure of oxygen. The effect of HH (1, 3, and 7 days at 25,000 ft) on social memory, anxiety, adult neurogenesis, and NLRP3- (NLR family pyrin domain containing 3) mediated neuroinflammation in the dentate gyrus (DG) was explored in detail. Furthermore, we explored the therapeutic efficacy of cyclooxygenase-1 inhibitor (valeryl salicylate, 5 mg/kg/day, i.p.) and EP1 receptor (EP1R) antagonist (SC19220, 1 mg/kg/day, i.p.) on HH-induced deficits. Seven days of HH exposure induced alteration in social and anxiety-like behavior along with perturbation in adult neurogenesis. Elevation in NLRP3, caspase-1, and IL-1ß levels was observed during HH from day 1. A notable increase in the COX-1/EP1R pathway in activated glial cells in DG was evident during HH. COX-1 inhibitor and EP1R antagonist mitigated the detrimental effects of HH on social memory, adult neurogenesis via blunting NLRP3-mediated inflammation. Our data showed induction of the COX-1/EP1R pathway in the glial cells, which is detrimental to neurogenesis and social memory, opening up the possibility that the COX-1/EP1R pathway is a plausible target for inflammasome-related neurogenesis impairments.

TMT-Based Plasma Proteomics Reveals Dyslipidemia Among Lowlanders During Prolonged Stay at High Altitudes.

Acute exposure to high altitude perturbs physiological parameters and induces an array of molecular changes in healthy lowlanders. However, activation of compensatory mechanisms and biological processes facilitates high altitude acclimatization. A large number of lowlanders stay at high altitude regions from weeks to months for work and professional commitments, and thus are vulnerable to altitude-associated disorders. Despite this, there is a scarcity of information for molecular changes associated with long-term stay at high altitudes. In the present study, we evaluated oxygen saturation (SpO2), heart rate (HR), and systolic and diastolic blood pressure (SBP and DBP) of lowlanders after short- (7 days, HA-D7) and long-term (3 months, HA-D150) stay at high altitudes, and used TMT-based proteomics studies to decipher plasma proteome alterations. We observed improvements in SpO2 levels after prolonged stay, while HR, SBP, and DBP remained elevated as compared with short-term stay. Plasma proteomics studies revealed higher levels of apolipoproteins APOB, APOCI, APOCIII, APOE, and APOL, and carbonic anhydrases (CA1 and CA2) during hypoxia exposure. Biological network analysis also identified profound alterations in lipoprotein-associated pathways like plasma lipoprotein assembly, VLDL clearance, chylomicron assembly, chylomicron remodeling, plasma lipoprotein clearance, and chylomicron clearance. In corroboration, lipid profiling revealed higher levels of total cholesterol (TC), triglycerides (TGs), low-density lipoprotein (LDL) for HA-D150 whereas high density lipoproteins (HDL) levels were lower as compared with HA-D7 and sea-level indicating dyslipidemia. We also observed higher levels of proinflammatory cytokines IL-6, TNFα, and CRP for HA-D150 along with oxidized LDL (oxLDL), suggesting vascular inflammation and proartherogenic propensity. These results demonstrate that long-term stay at high altitudes exacerbates dyslipidemia and associated disorders.

Cardiac Acclimatization at High Altitude in Two Different Ethnicity Groups.

Gaur, Priya, Meerim Sartmyrzaeva, Abdirashit Maripov, Kubatbek Muratali Uulu, Supriya Saini, Koushik Ray, Krishna Kishore, Almaz Akunov, Akpay Sarybaev, Bhuvnesh Kumar, Shashi Bala Singh, and Praveen Vats. Cardiac acclimatization at high altitude in two different ethnicity groups. High Alt Med Biol. 22:58-69, 2021. Introduction: High altitude (HA) exposure causes substantial increase in pulmonary artery pressure (PAP) and resistance. However, the effects of HA hypoxia exposure on cardiac function remain incompletely understood. Studies evaluating interethnic differences in cardiac functions in response to HA exposure are lacking. We aimed to compare the cardiac performance in Indian versus Kyrgyz healthy lowland subjects over the course of a 3-week HA exposure at 4,111 m. Methodology: Ten Indians and 20 Kyrgyz subjects were studied to assess cardiac acclimatization noninvasively by echocardiography in two different ethnic groups for 3 weeks of stay at HA. Pulmonary hemodynamics, right and left ventricular functions were evaluated at basal and on days 3, 7, 14, and 21 of HA exposure and on day 3 of deinduction. Results: HA exposure significantly increased PAP, pulmonary vascular resistance, cardiac output (CO), and heart rates (HRs) in both groups. Tricuspid regurgitant gradient increased significantly in both the group at day 3 versus basal; 38.9 mmHg (31.8, 42.9) versus 21.9 mmHg (19.5, 22.6) in Kyrgyz; and 34.1 mmHg (30.2, 38.5) versus 20.4 mmHg (19.7, 21.3) in Indians. HR increased significantly in Indians at day 3 and 7, whereas in Kyrgyz throughout exposure. CO increased significantly in both groups at day 3 versus basal with 5.9 L/min (5.5, 6.4) versus 5.1 L/min (4.4, 5.9) in Kyrgyz, and 5.7 L/min (5.56, 5.98) versus 4.9 L/min (4.1, 5.3) in Indians. Both groups exhibited preserved right ventricular diastolic and systolic functions at HAs. HA exposure changed the left ventricular diastolic parameters only in Kyrgyz subjects with impaired mitral inflow E/A, but not in Indian subjects. All cardiac changes induced at HAs have been recovered fully upon deinduction in both, except lateral-septal A', which remained low in Indians. Conclusion: Although pulmonary hemodynamics responses were similar in both groups, there were differences in cardiac functional parameters between the two in response to HA exposure that may be accounted to ethnic variation.

Temporal transcriptome analysis suggest modulation of multiple pathways and gene network involved in cell-cell interaction during early phase of high altitude exposure.

High altitude (HA) conditions induce several physiological and molecular changes, prevalent in individuals who are unexposed to this environment. Individuals exposed towards HA hypoxia yields physiological and molecular orchestration to maintain adequate tissue oxygen delivery and supply at altitude. This study aimed to understand the temporal changes at altitude of 4,111m. Physiological parameters and transcriptome study was conducted at high altitude day 3, 7, 14 and 21. We observed changes in differentially expressed gene (DEG) at high altitude time points along with altered BP, HR, SpO2, mPAP. Physiological changes and unsupervised learning of DEG's discloses high altitude day 3 as distinct time point. Gene enrichment analysis of ontologies and pathways indicate cellular dynamics and immune response involvement in early day exposure and later stable response. Major clustering of genes involved in cellular dynamics deployed into broad categories: cell-cell interaction, blood signaling, coagulation system, and cellular process. Our data reveals genes and pathways perturbed for conditions like vascular remodeling, cellular homeostasis. In this study we found the nodal point of the gene interactive network and candidate gene controlling many cellular interactive pathways VIM, CORO1A, CD37, STMN1, RHOC, PDE7B, NELL1, NRP1 and TAGLN and the most significant among them i.e. VIM gene was identified as top hub gene. This study suggests a unique physiological and molecular perturbation likely to play a critical role in high altitude associated pathophysiological condition during early exposure compared to later time points.

Hypobaric hypoxia induced fear and extinction memory impairment and effect of Ginkgo biloba in its amelioration: Behavioral, neurochemical and molecular correlates.

Regulated fear and extinction memory is essential for balanced behavioral response. Limbic brain regions are susceptible to hypobaric hypoxia (HH) and are putative target for fear extinction deficit and dysregulation. The present study aimed to examine the effect of HH and Ginkgo biloba extract (GBE) on fear and extinction memory with the underlying mechanism. Adult male Sprague-Dawley rats were evaluated for fear extinction and anxious behavior following GBE administration during HH exposure. Blood and tissue (PFC, hippocampus and amygdala) samples were collected for biochemical, morphological and molecular studies. Results revealed deficit in contextual and cued fear extinction following 3 days of HH exposure. Increased corticosterone, glutamate with decreased GABA level was found with marked pyknosis, decrease in apical dendritic length and number of functional spines. Decline in mRNA expression level of synaptic plasticity genes and immunoreactivity of BDNF, synaptophysin, PSD95, spinophilin was observed following HH exposure. GBE administration during HH exposure improved fear and extinction memory along with decline in anxious behavior. It restored corticosterone, glutamate and GABA levels with an increase in apical dendritic length and number of functional spines with a reduction in pyknosis. It also improved mRNA expression level and immunoreactivity of neurotrophic and synaptic proteins. The present study is the first which demonstrates fear extinction deficit and anxious behavior following HH exposure. GBE administration ameliorated fear and extinction memory dysregulation by restoration of neurotransmitter levels, neuronal pyknosis and synaptic connections along with improved neurotrophic and synaptic protein expressions.

Fear memory is impaired in hypobaric hypoxia: Role of synaptic plasticity and neuro-modulators in limbic region.

AIMS: Evidence suggests that hypobaric hypoxia (HH) exposure causes biochemical and molecular level perturbations in brain resulting in associated cognitive dysfunction. However, the possible effect of HH on amygdala and the associated limbic regions based functions remains elusive. Regulated fear expression is essential for quick adaptations and optimal behavioral response. Therefore, the present study aims to investigate the effect of HH on biochemical and molecular mechanisms in amygdala involved in fear memory regulation along with the hippocampus and prefrontal cortex based fear memory. MATERIALS AND METHODS: Adult male Sprague Dawley rats were subjected to cued and contextual fear memory assessment following simulated HH exposure (25,000 ft) for 3 and 7 days. Plasma and limbic tissue (Prefrontal cortex, hippocampus and amygdala) samples were collected for biochemical and molecular studies. KEY FINDINGS: Results revealed a decrease in contextual and cued fear memory retrieval, indicating fear memory dysregulation under HH exposure. Increased level of norepinephrine, dopamine, corticosterone and glutamate along with a decline in serotonin and GABA level was observed in plasma and limbic tissue after 3 and 7 days of HH exposure. Dysregulation of neuromodulation, neuronal survival and synaptic homeostasis was also evident from observed decline in tryptophan hydroxylase, BDNF, synaptophysin, synapsin1, PSD95 and an increase in tyrosine hydroxylase immunoreactivity in limbic region under HH exposure. SIGNIFICANCE: Dysregulation of limbic region signaling molecules associated with survival and maintenance of synaptic plasticity (Synaptophysin, synapsin1 and PSD95), neurotrophic factor (BDNF) and shift in monoamines, corticosterone, glutamate and GABA levels may contribute to the HH induced fear memory impairment.

Complement activation sustains neuroinflammation and deteriorates adult neurogenesis and spatial memory impairment in rat hippocampus following sleep deprivation.

BACKGROUND: An association between neuroinflammation, reduced adult neurogenesis, and cognitive impairment has been established in sleep deprivation (SD). Complement receptors are expressed on neuronal and glial cells, thus, regulate the neuroinflammation, neurogenesis and learning/memory. However, understanding of the effect of SD on the brain-immune system interaction associated with cognitive dysfunction and its mechanisms is obscure. We hypothesized that complement activation induced changes in inflammatory and neurogenesis related proteins might be involved in the cognitive impairment during SD. METHODOLOGY: Adult male Sprague Dawley rats were used. Rats were sleep deprived for 48 h using a novel automated SD apparatus. Dosage of BrdU (50 mg/kg/day, i.p. in 0.07 N NaOH), complement C3a receptor antagonist (C3aRA; SB290157; 1 mg/kg/day, i.p.) in 1.16% v/v PBS and complement C5a receptor antagonist (C5aRA; W-54011; 1 mg/kg/day, i.p.) in normal saline were used. Rats were subjected to spatial memory evaluation following SD. Hippocampal tissue was collected for biochemical, molecular, and immunohistochemical studies. T-test and ANOVA were used for the statistical analysis. RESULTS: An up-regulation in the levels of complement components (C3, C5, C3a, C5a) and receptors (C3aR and C5aR) in hippocampus, displayed the complement activation during SD. Selective antagonism of C3aR/C5aR improved the spatial memory performance of sleep-deprived rats. C3aR antagonist (C3aRA) or C5aR antagonist (C5aRA) treatment inhibited the gliosis, maintained inflammatory cytokines balance in hippocampus during SD. Complement C3aR/C5aR antagonism improved hippocampal adult neurogenesis via up-regulating the BDNF level following SD. Administration of C3aRA and C5aRA significantly maintained synaptic homeostasis in hippocampus after SD. Gene expression analysis showed down-regulation in the mRNA levels of signal transduction pathways (Notch and Wnt), differentiation and axogenous proteins, which were found to be improved after C3aRA/C5aRA treatment. These findings were validated at protein and cellular level. Changes in the corticosterone level and ATP-adenosine-NO pathway were established as the key mechanisms underlying complement activation mediated consequences of SD. CONCLUSION: Our study suggests complement (C3a-C3aR and C5a-C5aR) activation as the novel mechanism underlying spatial memory impairment via promoting neuroinflammation and adult neurogenesis decline in hippocampus during SD, thereby, complement (C3aR/C5aR) antagonist may serve as the novel therapeutics to improve the SD mediated consequences.

A Temporal Study on Learning and Memory at High Altitude in Two Ethnic Groups.

Introduction: Cognitive function has been compromised during high-altitude (HA) exposure due to slowing of mental processing. Materials and Methods: A total of 20 Indian and 20 Kyrgyz soldiers were studied at 4111 m to assess cognitive function in two different ethnic groups. Paired associate learning, pattern recognition memory, spatial span (SSP), spatial working memory (SWM), choice reaction time (CRT), and simple reaction time (SRT) were evaluated at sea level and on days 3, 7, 14, and 21 of HA stay and on day 3 of deinduction. Results: All the parameters were significantly affected at HA. Indian soldiers were acclimatized by 7 days but Kyrgyz soldiers required 21 days for acclimatization. A slow impairment in SWM, CRT, and SRT was observed in Kyrgyz soldiers than in Indian soldiers and it continues throughout 21 days of HA stay, but for Indian soldiers the deterioration was maximum on day 7 and improvement in SWM, CRT, and SRT was observed on day 14 and close to baseline value on day 21. After deinduction, although Indian soldiers attained the normal value, Kyrgyz soldiers had higher value than baseline in SSP, SWM, CRT, and SRT. Conclusion: Difference in the cognitive performances of Indian and Kyrgyz soldiers may be due to the ethnogenetic diversity of these two groups.

Reduced expression of Kalirin-7 contributes to working memory deficit during chronic hypobaric hypoxia exposure.

Hypobaric hypoxia (HH) is an environmental stress encountered at high altitude. It has been shown that HH resulted in spine atrophy and working memory deficits. Kalirin-7, a postsynaptic density protein, plays an important and key role in regulating spine dynamics and its plasticity. Spine atrophy is implicated in HH induced memory deficits but role of Kalirin-7 in this phenomenon is not studied. Present study is therefore designed to investigate the effect of chronic HH exposure on Kalirin-7 expression in hippocampus and its role in spatial working memory deficits. Adult rats (n = 12, 3 months old) were exposed to a simulated altitude of 25,000 feet for 7 days. Following HH exposure, spatial working memory was assessed with Radial arm maze and T maze. Hippocampal expression of Kalrin-7 was estimated at mRNA and protein levels. Results of behavioural experiments showed that HH causes significant decrease in the spatial working memory. There was a significant reduction in the protein expression of Kalirin-7 in the hippocampus of hypoxia exposed rats (43.89 ± 7.43) as compared to the control (69.54 ± 10.99). The mRNA expression of Kalrin-7 also exhibits significant reduction (0.59 ± 0.05) in the exposed group as compared to the control (0.98 ± 0.07). Immunohistochemistry showed that Kalirin-7 is decreased significantly in CA1, CA3 and DG regions of the hippocampus. Moreover, memory deficits are significantly correlated with decreased immunoreactivity of the hippocampal Kalirin-7. In conclusion, it can be said therefore, that change in Kalirin-7 expression in the hippocampus is associated with HH induced working memory deficit.

Global expression profiling and pathway analysis in two different population groups in relation to high altitude.

High altitude (HA) is associated with number of stresses. Response of these stresses may vary in different populations depending upon altitude, duration of residency, ancestry, geographical variation, lifestyle, and ethnicities. For understanding population variability in transcriptome, array-based global gene expression profiling was performed on extracted RNA of male volunteers of two different lowland population groups, i.e., Indians and Kyrgyz, at baseline and day 7 of HA exposure (3200 m). A total of 97 genes were differentially expressed at basal in Kyrgyz as compared to Indians (82 downregulated and 15 upregulated), and 196 were differentially expressed on day 7 of HA (118 downregulated and 78 upregulated). Ingenuity Pathway Analysis and gene ontology highlighted eIF2 signaling with most significant negative activation z score at basal in Kyrgyz compared to Indians with downregulation of various L- and S-ribosomal proteins indicating marked translational repression. On day 7, cAMP-mediated signaling is most enriched with positive activation z score in Kyrgyz compared to Indians. Plasma cAMP levels were higher in Kyrgyz on day 7 compared to Indians. Extracellular adenosine levels were elevated in both the groups upon HA, but higher in Kyrgyz compared to Indians. Valedictory qRT-PCR showed upregulation of ADORA2B and CD73 along with downregulation of ENTs in Kyrgyz compared to Indians indicating elevated levels of extracellular nucleotides mainly adenosine and activation of extracellular cAMP-adenosine pathway which as per literature triggers endogenous protective mechanisms under stress conditions like hypoxia. Thus, transcriptome changes at HA are population-specific, and it may be necessary to take care while interposing similar results in different populations.

Distinct influence of COX-1 and COX-2 on neuroinflammatory response and associated cognitive deficits during high altitude hypoxia.

High-altitude hypoxia (HH) causes a spectrum of pathophysiological effects, including headaches, gliovascular dysfunction, and cognitive slowing. Previous studies have shown arachidonic acid (AA) metabolism due to cyclooxygenase (COX) activity before clinical manifestations in many diseases. AA metabolites, including COXs and prostaglandin E2 (PGE2), are well known immunomodulators. However, the relative contribution of COX-2 and COX-1 isoforms in the downstream proinflammatory responses and cognitive deficit in HH remains unknown. In the present study, AA metabolism via the COX pathway was investigated in Sprague Dawley rats after 0, 1, 3, and 7 days of HH exposure. Furthermore, we investigated the inflammatory response and cell-type-specific induction of both COXs. Our data revealed that AA metabolites peaked on day 3 of HH exposure. Interestingly, we observed endothelial and microglial activation on day 1, accompanied by an increase in the levels of proinflammatory cytokines, followed by astrocyte activation on day 3. We showed that the increase in COX activity during HH culminated in a significant increase in hippocampal inflammation, concomitant with spatial memory impairment and neuronal injury at day 7 of HH. We showed HH induced distinct COX-1 expression in endothelial and microglial cells, whereas it induced COX-2 expression predominantly in neurons, endothelial cells, and astrocytes. Notably, our data showed that the inhibition of COX-1 using valeryl salicylate had a prominent role in containing hippocampal inflammation by reducing microglial activation. COX-2 inhibition using celecoxib, along with COX-1 inhibition, ameliorated spatial memory impairment, astrocyte activation, and neurodegeneration after HH exposure.

Phosphorylated delta sleep inducing peptide restores spatial memory and p-CREB expression by improving sleep architecture at high altitude.

AIMS: Sleep loss at high altitude (HA) play major role in worsening of neuropsychological functions, such as attention, memory and decision making. This study investigates the role of phosphorylated delta sleep inducing peptide (p-DSIP) in improving sleep architecture during chronic hypobaric hypoxia (HH) exposure and restoration of spatial navigational memory. METHODS: Morris water maze (MWM) trained rats were exposed to HH at 7620 m. p-DSIP was injected intra-peritoneally (10 µg/Kg bw) during HH exposure as an intervention against sleep alteration. Sleep architecture was recorded telemetrically before and during HH exposure. Monoamines were estimated by high performance liquid chromatography from brain stem (BS) and hypothalamus. CREB and p-CREB level in hippocampus was studied by western blotting and expression of different monoamine regulatory enzymes in BS was measured by flow cytometry. Naloxone (1 mg/kg bw), a µ opioid receptor antagonist of sleep inducing effect of DSIP was also studied. KEY FINDINGS: p-DSIP injection daily in circadian active period (18.30 h) during chronic HH enhanced non rapid eye movement sleep, rapid eye movement sleep as well as improved MWM performance of rats. p-DSIP treatment showed lower monoamine level and tyrosine hydroxylase (TH) expression and increased monoamine oxidase A (MAO A), glutamic acid decarboxylase (GAD) and Choline acetyltransferase (ChAT) expression. Further, naloxone altered navigational memory by decreasing the CREB and p-CREB level in hippocampus suggesting suppression of sleep inducing effect of p-DSIP. SIGNIFICANCE: Our study demonstrates that improvement of sleep quality by p-DSIP restores spatial memory by up regulating CREB phosphorylation during simulated high altitude hypoxia.

Hypobaric hypoxia impairs cued and contextual fear memory in rats.

Fear memory is essential for survival, and its dysregulation leads to disorders. High altitude hypobaric hypoxia (HH) is known to induce cognitive decline. However, its effect on fear memory is still an enigma. We aimed to investigate the temporal effect of HH on fear conditioning and the underlying mechanism. Adult male Sprague-Dawley rats were trained for fear conditioning and exposed to simulated HH equivalent to 25,000 ft for different durations (1, 3, 7, 14 and 21 days). Subsequently, rats were tested for cued and contextual fear conditioning. Neuronal morphology, apoptosis and DNA fragmentation were studied in the medial prefrontal cortex (mPFC), hippocampus and basolateral amygdala (BLA). We observed significant deficit in cued and contextual fear acquisition (at 1, 3 and 7 days) and consolidation (cued at 1 and 3 days and contextual fear at 1, 3 and 7 days) under HH. HH exposure with retraining showed the earlier restoration of contextual fear memory. Further, we found a gradual increase in the number of pyknotic and apoptotic neurons together with the increase in DNA fragmentation in mPFC, hippocampus, and BLA up to 7 days of HH exposure. The present study concludes that HH exposure equivalent to 25,000 ft induced cued and contextual fear memory deficit (acquisition and consolidation) which is found to be correlated with the neurodegenerative changes in the limbic brain regions.

Caffeine and Modafinil Ameliorate the Neuroinflammation and Anxious Behavior in Rats during Sleep Deprivation by Inhibiting the Microglia Activation.

Background: Sleep deprivation (SD) plagues modern society due to the professional demands. It prevails in patients with mood and neuroinflammatory disorders. Although growing evidence suggests the improvement in the cognitive performance by psychostimulants during sleep-deprived conditions, the impending involved mechanism is rarely studied. Thus, we hypothesized that mood and inflammatory changes might be due to the glial cells activation induced modulation of the inflammatory cytokines during SD, which could be improved by administering psychostimulants. The present study evaluated the role of caffeine/modafinil on SD-induced behavioral and inflammatory consequences. Methods: Adult male Sprague-Dawley rats were sleep deprived for 48 h using automated SD apparatus. Caffeine (60 mg/kg/day) or modafinil (100 mg/kg/day) were administered orally to rats once every day during SD. Rats were subjected to anxious and depressive behavioral evaluation after SD. Subsequently, blood and brain were collected for biochemical, immunohistochemical and molecular studies. Results: Sleep deprived rats presented an increased number of entries and time spent in closed arms in elevated plus maze test and decreased total distance traveled in the open field (OF) test. Caffeine/modafinil treatment significantly improved these anxious consequences. However, we did not observe substantial changes in immobility and anhedonia in sleep-deprived rats. Caffeine/modafinil significantly down-regulated the pro- and up-regulated the anti-inflammatory cytokine mRNA and protein expression in the hippocampus during SD. Similar outcomes were observed in blood plasma cytokine levels. Caffeine/modafinil treatment significantly decreased the microglial immunoreactivity in DG, CA1 and CA3 regions of the hippocampus during SD, however, no significant increase in immunoreactivity of astrocytes was observed. Sholl analysis signified the improvement in the morphological alterations of astrocytes and microglia after caffeine/modafinil administration during SD. Stereological analysis demonstrated a significant improvement in the number of ionized calcium binding adapter molecule I (Iba-1) positive cells (different states) in different regions of the hippocampus after caffeine or modafinil treatment during SD without showing any significant change in total microglial cell number. Eventually, the correlation analysis displayed a positive relationship between anxiety, pro-inflammatory cytokines and activated microglial cell count during SD. Conclusion: The present study suggests the role of caffeine or modafinil in the amelioration of SD-induced inflammatory response and anxious behavior in rats. Highlights - SD induced mood alterations in rats. - Glial cells activated in association with the changes in the inflammatory cytokines. - Caffeine or modafinil improved the mood and restored inflammatory changes during SD. - SD-induced anxious behavior correlated with the inflammatory consequences.

Inhibiting the microglia activation improves the spatial memory and adult neurogenesis in rat hippocampus during 48 h of sleep deprivation.

BACKGROUND: Sleep deprivation (SD) leads to cognitive impairment. Neuroinflammation could be a significant contributing factor in the same. An increase in regional brain pro-inflammatory cytokines induces cognitive deficits, however, the magnitude of the effect under SD is not apparent. It is plausible that microglia activation could be involved in the SD-induced cognitive impairment by modulation of neuronal cell proliferation, differentiation, and brain-derived neuronal factor (BDNF) level. The present study aimed to evaluate the possible beneficial effect of minocycline in amelioration of spatial memory decline during SD by its anti-inflammatory and neuroprotective actions. We scrutinized the effect of minocycline on the inflammatory cytokine levels associated with glial cells (microglia and astrocytes) activity and neurogenesis markers crucial for behavioral functions during SD. METHODS: Male Sprague-Dawley rats weighing 230-250 g were sleep deprived for 48 h using automated cage shaking apparatus. The spatial memory was tested using MWM apparatus immediately after completion of SD with and without minocycline. The animals were euthanized, blood was collected, and brain was extracted for neuroinflammation and neurogenesis studies. The set of experiments were also conducted with use of temozolomide, a neurogenesis blocker. RESULTS: Minocycline treatment increased the body weight, food intake, and spatial memory performance which declined during SD. It reduced the pro-inflammatory and increased the anti-inflammatory cytokine levels in hippocampus and plasma and inhibited the reactive gliosis in the hippocampus evidenced by improved cell count, morphology, and immunoreactivity. Additionally, minocycline administration promoted neurogenesis at different stages: proliferation (BrdU, Ki-67), differentiation (DCX) cells and growth factor (BDNF). However, no significant change was observed in maturation (NeuN) during SD. In addition, molecules related to behavior, inflammation, and neurogenesis were shown to be more affected after temozolomide administration during SD, and changes were restored with minocycline treatment. We observed a significant correlation of neurogenesis with microglial activation, cytokine levels, and spatial memory during SD. CONCLUSION: The present study demonstrated that the SD-induced decline in spatial memory, neuronal cells proliferation, differentiation, and BDNF level could be attributed to upregulation of neuroinflammatory molecules, and minocycline may be an effective intervention to counteract these changes. Microglial activation is involved in SD-induced changes in inflammatory molecules, neurogenesis, and spatial memory.

Sleep deprivation induces spatial memory impairment by altered hippocampus neuroinflammatory responses and glial cells activation in rats.

We aimed to investigate the glial cells activation as a potential mechanism involved in the sleep deprivation (SD) induced cognitive impairment through changes in inflammatory cytokines. We analyzed the spatial memory, inflammatory cytokine levels, and gliosis during SD. SD induced spatial memory impairment, imbalance of inflammatory (increased pro- and decreased anti-) cytokines in both hippocampus and plasma in association with glial cells activation in the hippocampus of sleep-deprived rats were observed. Further analysis of the data presented a correlation between spatial memory impairment and activated microglia induced increased pro-inflammatory cytokines after 48h of SD.

Tyrosine ameliorates heat induced delay in event related potential P300 and contingent negative variation.

The efficacy of tyrosine, a catecholamine precursor, as a countermeasure in the reduction of cognitive decline during heat exposure (HE) using event-related potential P300, and contingent negative variation (CNV) was evaluated. Ten healthy males, age 20-30years participated in the study. Volunteers received placebo or tyrosine (6.5g) 90min prior to HE (1.5h in 45°C+30% RH). P300 latency was significantly increased (p<0.01) during exposure with placebo, which was reduced significantly (p<0.01) after tyrosine supplementation. There was an increase in CNV M100 latency (p<0.05) and reaction time (p<0.01) and decrease in M100 amplitude (p<0.01) during HE with placebo, which returns to near normal level with the tyrosine administration. A significantly higher plasma norepinephrine (p<0.05), dopamine and epinephrine levels were detected in tyrosine supplemented group post heat exposure. HE increases the brain catecholamine activity thereby reduces the plasma norepinephrine and dopamine level leading to a reduction in cognitive performances. Tyrosine supplementation increases the catecholamine level and reduces the impairment of cognitive performance during HE.

Caffeine and modafinil promote adult neuronal cell proliferation during 48 h of total sleep deprivation in rat dentate gyrus.

It has been established that sleep deprivation (SD) reduces the proliferation of neuronal precursors in the adult hippocampus. It has also been reported that psychostimulant drugs modulate adult neurogenesis. We examined the modulatory role of two psychostimulant drugs modafinil and caffeine on adult neuronal cell proliferation (NCP) during 48 h of total SD. A novel automated cage shaking stimulus was used to induce SD based on animal activity. 5-Bromo-2″-deoxyuridine (BrdU; 50mg/kg/day i.p.) was injected at the onset of the light phase for two days. Rats were successfully sleep deprived for 85-94% of total time. Stereological analysis showed that both caffeine and modafinil treatments during SD improved the number of BrdU positive cells as compared to the SD group. Caffeine treatment during SD, significantly increased early proliferative and post-mitotic stages of doublecortin (DCX) positive cells while modafinil treatment during SD, increased intermediate and post-mitotic stages of DCX positive cells compared to SD+Vehicle group. Brain-Derived Neurotrophic Factor (BDNF) expression on BrdU positive cells as well as in the dentate gyrus (DG) region was decreased significantly after sleep deprivation. Both caffeine and modafinil significantly improved BDNF expression in the DG region. Modafinil, but not caffeine, significantly decreased hippocampal adenosine level during SD in comparison to the SD+Vehicle group. It may be concluded that caffeine or modafinil treatment during 48 h of SD prevents the SD induced decline in neuronal proliferation and differentiation. Caffeine and modafinil induced alterations of NCP during SD may involve modulation of BDNF and adenosine levels.

Changes in cardiovascular functions, lipid profile, and body composition at high altitude in two different ethnic groups.

High altitude (HA) presents inhospitable environmental conditions that adversely affects human physiology and metabolism. Changes in physiological functions are reported during high altitude exposure, but the changes vary with physical state, culture habits, geographical locations, and genetic variation of individual. The present study was carried out to explore the variation in acclimatization pattern of two different ethnic groups in relation to cardiovascular functions, lipid profile and body composition. The study was carried out on 30 human volunteers (20 Indian and 10 Kyrgyz) initially at Bishkek for basal recording and on day 3, 7, 14, and 21 of high altitude (3200 m) induction and again on day 3 of de-induction. On altitude exposure significant decrease in body weight was observed both in Indian (day 14, p<0.001) and Kyrgyz (day 3, p<0.01) subjects. Decreased levels of total body water, extra cellular and intra cellular body water were also observed in both the groups. Significant reduction in body mass index (p<0.01), fat free mass (p<0.01), body cell mass (p<0.01) and body volume (p<0.01) was also observed in Kyrgyz subjects, whereas in Indian subjects the changes were not significant in these variables on high altitude exposure. Diastolic blood pressure and heart rate increased significantly on day 3 (p<0.001 and p<0.01, respectively) of induction in Indian subjects; whereas in Kyrgyz significant increase was observed on day 14 (p<0.05) in both the cases. High density lipoprotein (HDL) cholesterol levels increased significantly on day 7 of HA exposure in both the groups. Results indicate that the Indian and Kyrgyz groups report differently, in relation to changes in cardiovascular functions, lipid profiles, and body composition, when exposed to HA. The difference observed in acclimatization pattern in the two groups may be due to ethnic/genetic variation of two populations.