Does the melatonin receptor 1B gene polymorphism have a role in postoperative delirium?

Preventive Effects of Ramelteon, Suvorexant, and Lemborexant on Delirium in Hospitalized Patients With Physical Disease: A Retrospective Cohort Study

BACKGROUND

New sleep-inducing drugs (eg, ramelteon, suvorexant, and lemborexant) have been shown to prevent delirium in high-risk groups. However, no single study has simultaneously evaluated the delirium-preventing effects of all novel sleep-inducing drugs in hospitalized patients. Therefore, this study aimed to clarify the relationship between sleep-inducing drugs and delirium prevention in patients hospitalized in general medical-surgical settings for nonpsychiatric conditions who underwent liaison interventions for insomnia.

METHODS

This retrospective cohort study included patients treated in general medical-surgical settings for nonpsychiatric conditions with consultation-liaison psychiatry consult for insomnia. Delirium was diagnosed by fully certified psychiatrists using the Diagnostic and Statistical Manual of Mental Disorders 5 th edition. The following items were retrospectively examined from medical records as factors related to delirium development: type of sleep-inducing drugs, age, sex, and delirium risk factors. The risk factors of delirium development were calculated using adjusted odds ratios (aORs) via multivariate logistic regression analysis.

RESULTS

Among the 710 patients analyzed, 257 (36.2%) developed delirium. Suvorexant (aOR, 0.61; 95% confidence interval [CI], 0.40-0.94; P = 0.02) and lemborexant (aOR, 0.23; 95% CI, 0.14-0.39; P < 0.0001) significantly reduced the risk of developing delirium. Benzodiazepines (aOR, 1.90; 95% CI, 1.15-3.13; P = 0.01) significantly increased this risk. Ramelteon (aOR, 1.30; 95% CI, 0.84-2.01; P = 0.24) and Z-drugs (aOR, 1.27; 95% CI, 0.81-1.98; P = 0.30) were not significantly associated with delirium development.

CONCLUSIONS

The use of suvorexant and lemborexant may prevent delirium in patients with a wide range of medical conditions.

Prophylactic effect of exogenous melatonin and melatonin receptor agonists on postoperative delirium in elderly patients: a systemic review and meta-analysis of randomized controlled trials

BACKGROUND

The prophylactic effect of exogenous melatonin and melatonin receptor agonists (MMRAs) on postoperative delirium (POD) in elderly patients remains controversial.

OBJECTIVE

This study aimed to assess the prophylactic effect of MMRAs on POD by conducting a systemic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

We systematically searched four electronic databases including PubMed, Web of Science, Cochrane Library, and Embase for the eligible studies up to February 28, 2023. The Cochrane risk of bias tool was used for assessing the risk of bias in the included RCTs. The occurrence of POD was the primary outcome. The quality of evidence was evaluated by Grading of Recommendations Assessment, Development, and Evaluation.

RESULTS

A total of 11 RCTs comprising patients (MMRA group: 777 patients and placebo group: 781 patients) were included. The results of the meta-analysis showed that the MMRA group had a lower occurrence of POD than the placebo group (risk ratio = 0.70, 95% confidence interval: 0.51-0.97, P < 0.05, I2 = 59%). The subgroup analysis showed that melatonin significantly reduced the occurrence of POD (moderate-quality evidence), whereas ramelteon and tryptophan had no significant impact (moderate-quality evidence).

CONCLUSION

Existing evidence suggested that perioperative use of melatonin can prevent POD in elderly patients.

KIBRA, MTNR1B, and FKBP5 genotypes are associated with decreased odds of incident delirium in elderly post-surgical patients

Despite the association between cognitive impairment and delirium, little is known about whether genetic differences that confer cognitive resilience also confer resistance to delirium. To investigate whether older adults without postoperative delirium, compared with those with postoperative delirium, are more likely to have specific single nucleotide polymorphisms (SNPs) in the FKBP5, KIBRA, KLOTHO, MTNR1B, and SIRT1 genes known to be associated with cognition or delirium. This prospective nested matched exploratory case-control study included 94 older adults who underwent orthopedic surgery and screened for postoperative delirium. Forty-seven subjects had incident delirium, and 47 age-matched controls were not delirious. The primary study outcome was genotype frequency for the five SNPs. Compared with participants with delirium, those without delirium had higher adjusted odds of KIBRA SNP rs17070145 CT/TT [vs. CC; adjusted odds ratio (aOR) 2.80, 95% confidence interval (CI) 1.03, 7.54; p = 0.04] and MTNR1B SNP rs10830963 CG/GG (vs. CC; aOR 4.14, 95% CI 1.36, 12.59; p = 0.01). FKBP5 SNP rs1360780 CT/TT (vs. CC) demonstrated borderline increased adjusted odds of not developing delirium (aOR 2.51, 95% CI 1.00, 7.34; p = 0.05). Our results highlight the relevance of KIBRA, MTNR1B, and FKBP5 in understanding the complex relationship between delirium, cognition, and sleep, which warrant further study in larger, more diverse populations.

Membrane Melatonin Receptors Activated Cell Signaling in Physiology and Disease

The pineal hormone melatonin has attracted great scientific interest since its discovery in 1958. Despite the enormous number of basic and clinical studies the exact role of melatonin in respect to human physiology remains elusive. In humans, two high-affinity receptors for melatonin, MT1 and MT2, belonging to the family of G protein-coupled receptors (GPCRs) have been cloned and identified. The two receptor types activate Gi proteins and MT2 couples additionally to Gq proteins to modulate intracellular events. The individual effects of MT1 and MT2 receptor activation in a variety of cells are complemented by their ability to form homo- and heterodimers, the functional relevance of which is yet to be confirmed. Recently, several melatonin receptor genetic polymorphisms were discovered and implicated in pathology-for instance in type 2 diabetes, autoimmune disease, and cancer. The circadian patterns of melatonin secretion, its pleiotropic effects depending on cell type and condition, and the already demonstrated cross-talks of melatonin receptors with other signal transduction pathways further contribute to the perplexity of research on the role of the pineal hormone in humans. In this review we try to summarize the current knowledge on the membrane melatonin receptor activated cell signaling in physiology and pathology and their relevance to certain disease conditions including cancer.

The complex interaction of genetics and delirium: a systematic review and meta-analysis

The objective is to understand genetic predisposition to delirium. Following PRISMA guidelines, we undertook a systematic review of studies involving delirium and genetics in the databases of Pubmed, Scopus, Cochrane Library and PsycINFO, and performed a meta-analysis when appropriate. We evaluated 111 articles, of which 25 were finally included in the analysis. The studies were assessed by two independent researchers for methodological quality using the Downs and Black Tool and for genetic analysis quality. We performed a meta-analysis of 10 studies of the Apolipoprotein E (APOE) gene, obtaining no association with the presence of delirium (LOR 0.18, 95% CI - 0.10-0.47, p = 0.21). Notably, only 5 out of 25 articles met established criteria for genetic studies (good quality) and 6 were of moderate quality. Seven studies found an association with APOE4, the dopamine transporter gene SCL6A3, dopamine receptor 2 gene, glucocorticoid receptor, melatonin receptor and mitochondrial DNA haplotypes. One genome-wide association study found two suggestive long intergenic non-coding RNA genes. Five studies found no association with catechol-o-methyltransferase, melatonin receptor or several interleukins genes. The studies were heterogenous in establishing the presence of delirium. Future studies with large samples should further specify the delirium phenotype and deepen our understanding of interactions between genes and other biological factors.

Effects of Ramelteon on the Prevention of Postoperative Delirium in Older Patients Undergoing Orthopedic Surgery: The RECOVER Randomized Controlled Trial

OBJECTIVES

Postoperative delirium, associated with negative consequences including longer hospital stays and worse cognitive and physical outcomes, is frequently accompanied by sleep-wake disturbance. Our objective was to evaluate the efficacy and short-term safety of ramelteon, a melatonin receptor agonist, for the prevention of postoperative delirium in older patients undergoing orthopedic surgery.

DESIGN

A quadruple-masked randomized placebo-controlled trial (Clinical Trials.gov NCT02324153) conducted from March 2017 to June 2019.

SETTING

Tertiary academic medical center.

PARTICIPANTS

Patients aged 65 years or older, undergoing elective primary or revision hip or knee replacement.

INTERVENTION

Ramelteon (8 mg) or placebo MEASUREMENTS: Eighty participants were randomized to an oral gel cap of ramelteon or placebo for 3 consecutive nights starting the night before surgery. Trained research staff conducted delirium assessments for 3 consecutive days starting on postoperative day (POD) 0, after recovery from anesthesia, and on to POD2. A delirium diagnosis was based upon DSM-5 criteria determined by expert panel consensus.

RESULTS

Of 80 participants, five withdrew consent (one placebo, four ramelteon) and four were excluded (four ramelteon) after randomization. Delirium incidence during the 2 days following surgery was 7% (5 of 71) with no difference between the ramelteon versus placebo: 9% (3 of 33) and 5% (2 of 38), respectively. The adjusted odds ratio for postoperative delirium as a function of assignment to the ramelteon treatment arm was 1.28 (95% confidence interval: 0.21-7.93; z-value 0.27; p-value = 0.79). Adverse events were similar between the two groups.

CONCLUSION

In older patients undergoing elective primary or revision hip or knee replacement, ramelteon was not efficacious in preventing postoperative delirium.

The Role of Perioperative Sleep Disturbance in Postoperative Neurocognitive Disorders

Postoperative neurocognitive disorder (PND) increases the length of hospital stay, mortality, and risk of long-term cognitive impairment. Perioperative sleep disturbance is prevalent and commonly ignored and may increase the risk of PND. However, the role of perioperative sleep disturbances in PND remains unclear. Nocturnal sleep plays an indispensable role in learning, memory, and maintenance of cerebral microenvironmental homeostasis. Hospitalized sleep disturbances also increase the incidence of postoperative delirium and cognitive dysfunction. This review summarizes the role of perioperative sleep disturbances in PND and elucidates the potential mechanisms underlying sleep-deprivation-mediated PND. Activated neuroinflammation and oxidative stress; impaired function of the blood-brain barrier and glymphatic pathway; decreased hippocampal brain-derived neurotrophic factor, adult neurogenesis, and sirtuin1 expression; and accumulated amyloid-beta proteins are associated with PND in individuals with perioperative sleep disorders. These findings suggest that the improvement of perioperative sleep might reduce the incidence of postoperative delirium and postoperative cognitive dysfunction. Future studies should further investigate the role of perioperative sleep disturbance in PND.

MTNR1B gene on susceptibility to gestational diabetes mellitus: a two-stage hospital-based study in Southern China

Large-scale studies on genetic risk loci for melatonin receptor 1B (MTNR1B) gene and GDM risk have not been well generalized to the Chinese population. In this study, we performed two-stage case-control study: 1.429 pregnant women: 753 GDM/676 controls in the Southern Chinese population by genotyping 5 SNPs (rs10830963, rs1387153, rs2166706, rs1447352, and rs4753426) in MTNR1B. Genotypes were determined using the Sequenom MassARRAY platform and TaqMan allelic discrimination assay. Interactions between genetic variants and age/BMI as predictors of GDM risk were evaluated under the logistic regression model. In the first stage, the SNP rs10830963 was discovered to be potentially related to GDM risk (additive model: OR = 1.27, 95%CI = 1.05-1.55, P = 0.025), which was further confirmed in the second stage with a similar effect (additive model: OR = 1.53, 95%CI = 1.19-1.98, P = 0.005). In the combined stage, the G allele of rs10830963 was potentially associated with GDM risk (additive model: OR = 1.36, 95%CI = 1.17-1.59, P < 0.001; dominant model: OR = 1.45, 95%CI = 1.15-1.83, P = 0.005). The rs10830963 interacted with age and BMI to contribute to GDM risk in the combined participants. And, the similar interactive effects for the other four SNPs also exist. These findings offer the potential to improve our understanding of the etiology of GDM, and particularly of biological mechanisms.