PERIOD3 polymorphism is associated with sleep quality recovery after a mild traumatic brain injury

Genetic Variants and Persistent Impairment Following Mild Traumatic Brain Injury: A Systematic Review

OBJECTIVE

The purpose of this review is to systematically assess primary research publications on known genetic variants, which modify the risk for symptoms or dysfunction persisting 30 days or more following mild traumatic brain injury (mTBI).

SUMMARY OF REVIEW

A search of PubMed and Embase from inception through June 2022 identified 42 studies that associated genetic variants with the presence of symptoms or cognitive dysfunction 30 days or more following mTBI. Risk of bias was assessed for each publication using the Newcastle Ottawa Scale (NOS). Fifteen of the 22 studies evaluating apolipoprotein E ( APOE ) ɛ4 concluded that it was associated with worse outcomes and 4 of the 8 studies investigating the brain-derived neurotrophic factor ( BDNF ) reported the Val66Met allele was associated with poorer outcomes. The review also identified 12 studies associating 28 additional variants with mTBI outcomes. Of these, 8 references associated specific variants with poorer outcomes. Aside from analyses comparing carriers and noncarriers of APOE ɛ4 and BDNF Val66Met, most of the reviewed studies were too dissimilar, particularly in terms of specific outcome measures but also in genes examined, to allow for direct comparisons of their findings. Moreover, these investigations were observational and subject to varying degrees of bias.

CONCLUSIONS

The most consistent finding across articles was that APOE ɛ4 is associated with persistent post-mTBI impairment (symptoms or cognitive dysfunction) more than 30 days after mTBI. The sparsity of other well-established and consistent findings in the mTBI literature should motivate larger, prospective studies, which characterize the risk for persistent impairment with standardized outcomes in mTBI posed by other genetic variants influencing mTBI recovery.

Traumatic Brain Injury, Sleep, and Melatonin-Intrinsic Changes with Therapeutic Potential

Traumatic brain injury (TBI) is one of the most prevalent causes of morbidity in the United States and is associated with numerous chronic sequelae long after the point of injury. One of the most common long-term complaints in patients with TBI is sleep dysfunction. It is reported that alterations in melatonin follow TBI and may be linked with various sleep and circadian disorders directly (via cellular signaling) or indirectly (via free radicals and inflammatory signaling). Work over the past two decades has contributed to our understanding of the role of melatonin as a sleep regulator and neuroprotective anti-inflammatory agent. Although there is increasing interest in the treatment of insomnia following TBI, a lack of standardization and rigor in melatonin research has left behind a trail of non-generalizable data and ambiguous treatment recommendations. This narrative review describes the underlying biochemical properties of melatonin as they are relevant to TBI. We also discuss potential benefits and a path forward regarding the therapeutic management of TBI with melatonin treatment, including its role as a neuroprotectant, a somnogen, and a modulator of the circadian rhythm.

Circadian Rhythmicity of Vital Signs at Intensive Care Unit Discharge and Outcome of Traumatic Brain Injury

BACKGROUND

Physiological functions with circadian rhythmicity are often disrupted during illness.

OBJECTIVE

To assess the utility of circadian rhythmicity of vital signs in predicting outcome of traumatic brain injury (TBI).

METHODS

A retrospective single-center cohort study of adult intensive care unit (ICU) patients with largely isolated TBI to explore the relationship between the circadian rhythmicity of vital signs during the last 24 hours before ICU discharge and clinical markers of TBI severity and score on the Glasgow Outcome Scale 6 months after injury (GOS-6).

RESULTS

The 130 study participants had a median age of 39.0 years (IQR, 23.0-59.0 years), a median Glasgow Coma Scale score at the scene of 8.0 (IQR, 3.0-13.0), and a median Rotterdam score on computed tomography of the head of 3 (IQR, 3-3), with 105 patients (80.8%) surviving to hospital discharge. Rhythmicity was present for heart rate (30.8% of patients), systolic blood pressure (26.2%), diastolic blood pressure (20.0%), and body temperature (26.9%). Independent predictors of a dichotomized GOS-6 ≥4 were the Rotterdam score (odds ratio [OR], 0.38 [95% CI, 0.18-0.81]; P = .01), Glasgow Coma Scale score at the scene (OR, 1.22 [95% CI, 1.05-1.41]; P = .008), age (OR, 0.95 [95% CI, 0.92-0.98]; P = .003), oxygen saturation <90% in the first 24 hours (OR, 0.19 [95% CI, 0.05-0.73]; P = .02), serum sodium level <130 mmol/L (OR, 0.20 [95% CI, 0.05-0.70]; P = .01), and active intracranial pressure management (OR, 0.16 [95% CI, 0.04-0.62]; P = .008), but not rhythmicity of any vital sign.

CONCLUSION

Circadian rhythmicity of vital signs at ICU discharge is not predictive of GOS-6 in patients with TBI.

Prevalence of insomnia and insomnia symptoms following mild-traumatic brain injury: A systematic review and meta-analysis

Sleep is commonly disrupted following mild traumatic brain injury (mTBI), however there is a lack of consensus in the existing literature regarding the prevalence of insomnia/insomnia symptoms after injury. The aim of this review was to conduct a systematic review and meta-analysis of insomnia and insomnia symptoms' prevalence following mTBI. Full-text articles published in English in peer-reviewed journals, including adults with a clinical or self-reported mild traumatic brain injury diagnosis, were eligible for inclusion. Studies that assessed insomnia/insomnia symptoms after injury were included. Of the 2091 records identified, 20 studies were included in the review. 19 of these were meta-analysed (n = 95,195), indicating high heterogeneity among studies. Subgroup analyses indicated pooled prevalence estimates of post-mTBI insomnia disorder of 27.0% (95% CI 6.49-54.68) and insomnia symptoms of 71.7% (95% CI 60.31-81.85). The prevalence of insomnia is significantly higher in individuals who have sustained mild traumatic brain injury compared to prevalence estimates reported in the general population but high heterogeneity and methodological differences among studies make it difficult to provide reliable prevalence estimates. Future research should continue to advance our understanding of the onset, progression and impact of post-mild traumatic brain injury insomnia to promote the recovery and wellbeing of affected individuals. PROSPERO registration CRD42020168563.

Influence of Sleep Dysfunction on Concussion Assessment Outcomes Among Adolescent Athletes After Concussion and Healthy Controls

BACKGROUND

Sleep dysfunction (SD) is associated with a high symptom burden and lower neurocognitive performance after concussion and on baseline testing without injury. However, few studies have compared concussed athletes and controls with and without SD on clinical outcomes.

OBJECTIVE

To evaluate differences in clinical outcomes among both concussed athletes and matched controls with and without SD.

DESIGN

Retrospective cross-sectional study.

PARTICIPANTS

Participants aged 12 to 20 years were recruited from a concussion clinic (n = 50 patients) and research registry/flyers (n = 50 healthy age-/sex-matched controls). Participants were categorized by self-reported SD into one of 4 groups: sport-related concussion (SRC) + SD, SRC only, SD only, and controls.

MAIN OUTCOME MEASURES

Post-Concussion Symptom Scale (PCSS), Vestibular/Oculomotor Screening (VOMS), and neurocognitive testing (Immediate Postconcussion Assessment Cognitive Test).

RESULTS

Compared with the SRC only group, the SRC + SD group performed worse on all neurocognitive domains, had a higher total symptom score, and endorsed more symptoms on most VOMS items. In addition, the SRC + SD group was at an increased likelihood of having at least 1 abnormal VOMS item compared with SRC only group. The SRC only group had neurocognitive test scores and symptom reports statistically similar to the SD only group.

CONCLUSION

Sleep dysfunction after concussion is related to worse neurocognitive performance and higher concussion symptom reporting. This study extended findings to suggest vestibular symptomology is worse among athletes with SD after injury compared to injured athletes without SD. Similar performances on concussion assessments for the SRC only and SD only groups suggest SD may appear similar to clinical presentation of concussion, even at baseline in the absence of SRC.

Sleep Disturbances in the Acute Stage of Concussion are Associated With Poorer Long-Term Recovery: A Systematic Review

OBJECTIVE

To examine the association between sleep during the acute stage of concussion and long-term outcomes.

LITERATURE SURVEY

Literature searches were performed 1 July 2018 to 1 August 2018 in Ovid MEDLINE, CINAHL, and Web of Science, along with hand searching for gray literature and cited references. Of the 610 search results, 359 unique references were reviewed after duplicates were removed.

METHODOLOGY

Two reviewers independently reviewed and came to consensus on which titles/abstracts met inclusion/exclusion criteria (n = 23). The 23 full-text articles were assessed independently by the same two reviewers for eligibility. Consensus was achieved, leaving four articles for quality assessment and data extraction. One person extracted relevant data from each study using a standard data-extraction table. The data extraction table was reviewed by two reviewers and consensus was achieved for completeness and accuracy. Quality appraisal was conducted to assess the risk for potential bias and quality of included articles.

SYNTHESIS

Two of the articles included children younger than 16 years old and two included a wide age range. In general, poorer sleep was associated with poorer outcomes following concussion at reassessments across any age population. In addition, poorer sleep in the acute stage of concussion was associated with poorer long-term outcomes and recovery.

CONCLUSIONS

The variability in sleep assessments used, symptoms assessed, length of time to reassessments, and comparator group included made data synthesis challenging. The use of standard valid and reliable sleep assessments is recommended. Future studies may consider if addressing sleep disturbances early following concussion will improve longer-term outcomes.

The Association of Polymorphisms in Circadian Clock and Lipid Metabolism Genes With 2nd Trimester Lipid Levels and Preterm Birth

Deregulation of the circadian system in humans and animals can lead to various adverse reproductive outcomes due to genetic mutations and environmental factors. In addition to the clock, lipid metabolism may also play an important role in influencing reproductive outcomes. Despite the importance of the circadian clock and lipid metabolism in regulating birth timing few studies have examined the relationship between circadian genetics with lipid levels during pregnancy and their relationship with preterm birth (PTB). In this study we aimed to determine if single nucleotide polymorphisms (SNPs) in genes from the circadian clock and lipid metabolism influence 2^nd trimester maternal lipid levels and if this is associated with an increased risk for PTB. We genotyped 72 SNPs across 40 genes previously associated with various metabolic abnormalities on 930 women with 2^nd trimester serum lipid measurements. SNPs were analyzed for their relationship to levels of total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL) and triglycerides (TG) using linear regression. SNPs were also evaluated for their relationship to PTB using logistic regression. Five SNPs in four genes met statistical significance after Bonferroni correction (p < 1.8 × 10^-4) with one or more lipid levels. Of these, four SNPs were in lipid related metabolism genes: rs7412 in APOE with total cholesterol, HDL and LDL, rs646776 and rs599839 in CELSR2-PSRC1-SORT1 gene cluster with total cholesterol, HDL and LDL and rs738409 in PNPLA3 with HDL and TG and one was in a circadian clock gene: rs228669 in PER3 with TG. Of these SNPs only PER3 rs228669 was marginally associated with PTB (p = 0.02). In addition, PER3 rs228669 acts as an effect modifier on the relationship between TG and PTB.

Genetic Influences on Patient-Oriented Outcomes in Traumatic Brain Injury: A Living Systematic Review of Non-Apolipoprotein E Single-Nucleotide Polymorphisms

There is a growing literature on the impact of genetic variation on outcome in traumatic brain injury (TBI). Whereas a substantial proportion of these publications have focused on the apolipoprotein E (APOE) gene, several have explored the influence of other polymorphisms. We undertook a systematic review of the impact of single-nucleotide polymorphisms (SNPs) in non–apolipoprotein E (non-APOE) genes associated with patient outcomes in adult TBI). We searched EMBASE, MEDLINE, CINAHL, and gray literature from inception to the beginning of August 2017 for studies of genetic variance in relation to patient outcomes in adult TBI. Sixty-eight articles were deemed eligible for inclusion into the systematic review. The SNPs described were in the following categories: neurotransmitter (NT) in 23, cytokine in nine, brain-derived neurotrophic factor (BDNF) in 12, mitochondrial genes in three, and miscellaneous SNPs in 21. All studies were based on small patient cohorts and suffered from potential bias. A range of SNPs associated with genes coding for monoamine NTs, BDNF, cytokines, and mitochondrial proteins have been reported to be associated with variation in global, neuropsychiatric, and behavioral outcomes. An analysis of the tissue, cellular, and subcellular location of the genes that harbored the SNPs studied showed that they could be clustered into blood–brain barrier associated, neuroprotective/regulatory, and neuropsychiatric/degenerative groups. Several small studies report that various NT, cytokine, and BDNF-related SNPs are associated with variations in global outcome at 6–12 months post-TBI. The association of these SNPs with neuropsychiatric and behavioral outcomes is less clear. A definitive assessment of role and effect size of genetic variation in these genes on outcome remains uncertain, but could be clarified by an adequately powered genome-wide association study with appropriate recording of outcomes.

Update on Insomnia after Mild Traumatic Brain Injury

Sleep disturbance after traumatic brain injury (TBI) has received growing interest in recent years, garnering many publications. Insomnia is highly prevalent within the mild traumatic brain injury (mTBI) population and is a subtle, frequently persistent complaint that often goes undiagnosed. For individuals with mTBI, problems with sleep can compromise the recovery process and impede social reintegration. This article updates the evidence on etiology, epidemiology, prognosis, consequences, differential diagnosis, and treatment of insomnia in the context of mild TBI. This article aims to increase awareness about insomnia following mTBI in the hopes that it may improve diagnosis, evaluation, and treatment of sleeping disturbance in this population while revealing areas for future research.

Association of genetic variants with fatigue in patients with malignant glioma

Background

Fatigue is a consistently reported, severe symptom among patients with gliomas throughout the disease trajectory. Genomic pathways associated with fatigue in glioma patients have yet to be identified.

Methods

Clinical factors (performance status, tumor details, age, gender) were collected by chart review on glioma patients with fatigue ("I have lack of energy" on Functional Assessment of Cancer Therapy-Brain), as well as available genotyping data. Candidate genes in clock and inflammatory pathways were identified from a literature review, of which 50 single nucleotide polymorphisms (SNPs) in 7 genes were available. Clinical factors and SNPs identified by univariate analyses were included in a multivariate model for moderate-severe fatigue.

Results

The study included 176 patients (median age = 47 years, 67% males). Moderate-severe fatigue was reported by 43%. Results from multivariate analysis revealed poor performance status and 2 SNPs were associated with fatigue severity. Moderate-severe fatigue was more common in patients with poor performance status (OR = 3.52, P < .01). For each additional copy of the minor allele in rs934945 (PER2) the odds of fatigue decreased (OR = 0.51, P < .05). For each additional copy of the minor allele in rs922270 (ARTNL2) the odds of fatigue increased (OR = 2.38, P < .01). Both of these genes are important in the circadian clock pathway, which has been implicated in diurnal preference, and duration and quality of sleep. No genes in the inflammatory pathway were associated with fatigue in the current study.

Conclusions

Identifying patients at highest risk for fatigue during treatment allows for improved clinical monitoring and enrichment of patient selection for clinical trials.

Sleep-wake disturbance in patients with brain tumors

Sleep-wake disturbances are defined as perceived or actual alterations in sleep that result in impaired daytime functioning. Unlike other cancers, there is limited information about sleep-wake disturbances in adults with primary brain tumors throughout the illness trajectory. Sleep-wake disturbance is among the most severe and common symptoms reported by primary brain-tumor patients, particularly those undergoing radiation therapy. As with other cancers and neurologic illness, sleep-wake disturbance may also be clustered or related to other symptoms such as fatigue, depression, and cognitive impairment. There is increasing evidence for a genetic basis of normal sleep and sleep regulation in healthy adults. Specific mutations and single nucleotide variants have been reported to be associated with both fatigue and sleep-wake disorders, and both inflammation and alterations in circadian rhythms have been postulated to have a potential role. Guidelines for assessment and interventions have been developed, with cognitive behavioral therapy, exercise, and sleep hygiene demonstrating benefit in patients with other solid tumors. Further research is needed to identify risk and appropriate treatment in the brain-tumor patient population.

Hypocretinergic and cholinergic contributions to sleep-wake disturbances in a mouse model of traumatic brain injury

Disorders of sleep and wakefulness occur in the majority of individuals who have experienced traumatic brain injury (TBI), with increased sleep need and excessive daytime sleepiness often reported. Behavioral and pharmacological therapies have limited efficacy, in part, because the etiology of post-TBI sleep disturbances is not well understood. Severity of injuries resulting from head trauma in humans is highly variable, and as a consequence so are their sequelae. Here, we use a controlled laboratory model to investigate the effects of TBI on sleep-wake behavior and on candidate neurotransmitter systems as potential mediators. We focus on hypocretin and melanin-concentrating hormone (MCH), hypothalamic neuropeptides important for regulating sleep and wakefulness, and two potential downstream effectors of hypocretin actions, histamine and acetylcholine. Adult male C57BL/6 mice (n=6-10/group) were implanted with EEG recording electrodes and baseline recordings were obtained. After baseline recordings, controlled cortical impact was used to induce mild or moderate TBI. EEG recordings were obtained from the same animals at 7 and 15 days post-surgery. Separate groups of animals (n=6-8/group) were used to determine effects of TBI on the numbers of hypocretin and MCH-producing neurons in the hypothalamus, histaminergic neurons in the tuberomammillary nucleus, and cholinergic neurons in the basal forebrain. At 15 days post-TBI, wakefulness was decreased and NREM sleep was increased during the dark period in moderately injured animals. There were no differences between groups in REM sleep time, nor were there differences between groups in sleep during the light period. TBI effects on hypocretin and cholinergic neurons were such that more severe injury resulted in fewer cells. Numbers of MCH neurons and histaminergic neurons were not altered under the conditions of this study. Thus, we conclude that moderate TBI in mice reduces wakefulness and increases NREM sleep during the dark period, effects that may be mediated by hypocretin-producing neurons and/or downstream cholinergic effectors in the basal forebrain.