Inhibiting Histamine Signaling Ameliorates Vertigo Induced by Sleep Deprivation

The relationship between psychological conditions and recurrence of benign paroxysmal positional vertigo: a retrospective cohort study

BACKGROUND

Psychological conditions have been found to be associated with an increased risk of incident benign paroxysmal positional vertigo (BPPV). However, much less is known on whether and how psychological conditions such as anxiety, insomnia and obsessive-compulsive disorder (OCD) affect the recurrence of BPPV.

METHODS

A retrospective cohort study of 2,612 outpatients and inpatients diagnosed with BPPV between September 2012 and August 2020. BPPV recurrence was followed up until February 2021. The Cox proportional hazard regression was used to analyze the association between psychological conditions and the risk of the first recurrence. Poisson regression was applied to analyze the association between psychological conditions and the number of recurrences in patients with at least one relapse.

RESULTS

During the follow-up, 391 patients had at least one BPPV recurrence. Female BPPV patients were more likely than male patients to experience relapses than male patients, but the characteristics of BPPV recurrence (number of recurrences and duration between recurrences) did not differ between men and women. After adjustment for sex, age and comorbidities, a heightened risk of first BPPV recurrence was found to be associated with anxiety (hazard ratio [HR]: 1.30, 95% confidence interval [CI]: 1.01, 1.68) and OCD (HR: 2.15, 95% CI: 1.31, 3.52). An increased risk of first BPPV recurrence associated with insomnia was only observed in male patients (HR: 2.22, 95% CI: 1.24, 3.98) but not in female patients (HR: 0.91, 95% CI: 0.63, 1.31). None of these psychological conditions were associated with the number of recurrences in patients who experienced recurrence.

CONCLUSIONS

The presence of anxiety and OCD increased the risk of first BPPV recurrence, as well as insomnia for male patients. These psychological conditions were not associated with the number of BPPV recurrences. Diagnosis and treatment of these psychological conditions could be a useful strategy to prevent the recurrence of BPPV.

A review on pathophysiological aspects of Sleep Deprivation

Sleep deprivation (SD) (also referred as insomnia) is a condition in which peoples fails to get enough sleep due to excessive yawning, facing difficulty to learn new concepts, forgetfulness as well as depressed mood. This could be occurs due to several possible reasons including medications, stress (caused by shift work). Despite the fact that sleep is important for the normal physiology, it currently affects millions of people around the world US (70 million) and Europe (45 million). Due to increase work demand nowadays lots of peoples experiencing sleep deprivation hence, this could be the reason for several car accident followed by death and morbidity. This review highlighted the impact of SD on neurotransmitter release and functions, theories (Flip-flop theory, oxidative stress theory, neuroinflammation theory, neurotransmitter theory, and hormonal theory) associated with SD pathogenesis apart from this it also demonstrate the molecular pathways underlying SD (PI3K and Akt , NF-κB, Nrf2, and adenosine pathway. However, this study also elaborates the SD induced changes in the level of neurotransmitters, hormonal, and mitochondrial functions. Along with this, it also covers several molecular aspects associated with SD as well. Through this study a link is made between SD and associated causes, which will further help to develop potential therapeutic strategy against SD.

[Study on the relationship between benign paroxysmal positional vertigo and sleep disturbance]

Objective:To explore the relationship between benign paroxysmal positional vertigo （BPPV） and sleep disorders through the analysis of subjective and objective sleep conditions. Methods:Forty-five patients with BPPV and fifty controls who met the inclusion and exclusion criteria were selected for Pittsburgh sleep quality index （PSQI） questionnaire survey and polysomnography （PSG） check, and SPSS 23.0 was used to compare and analyze the results. Results:Compared with the control group, patients with BPPV had changes in sleep structure, high apnea hypopnea index （AHI） and significantly decreased subjective sleep quality （P<0.05）, and there were significant differences in the PQSI scores of patients with BPPV before and after treatment （P<0.05）.Binary logistic regression analysis of BPPV and AHI showed that for every 1 increase in AHI index, the probability of BPPV increased by 1.8 times （OR=2.80, 95%CI=2.25-3.66）.After grouping AHI and performing regression analysis, it was found that the risk of BPPV in patients with AHI≥5 was 3.94 times that of patients with AHI <5（OR=3.94，95%CI=1.63-9.48）. Conclusion:Patients with BPPV have decreased sleep quality and altered sleep structure, and in this study, AHI is found to be a risk indicator for BPPV.

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.

Histaminergic neurons in the tuberomammillary nucleus as a control centre for wakefulness

Histamine plays pleiotropic roles as a neurotransmitter in the physiology of brain function, this includes the maintenance of wakefulness, appetite regulation and memory retrieval. Since numerous studies have revealed an association between histaminergic dysfunction and diverse neuropsychiatric disorders, such as Alzheimer's disease and schizophrenia, a large number of compounds acting on the brain histamine system have been developed to treat neurological disorders. In 2016, pitolisant, which was developed as a histamine H₃ receptor inverse agonist by Schwartz and colleagues, was launched for the treatment of narcolepsy, emphasising the prominent role of brain histamine on wakefulness. Recent advances in neuroscientific techniques such as chemogenetic and optogenetic approaches have led to remarkable progress in the understanding of histaminergic neural circuits essential for the control of wakefulness. In this review article, we summarise the basic knowledge about the histaminergic nervous system and the mechanisms underlying sleep/wake regulation that are controlled by the brain histamine system. LINKED ARTICLES: This article is part of a themed issue on Neurochemistry in Japan. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.4/issuetoc.