Salivary Melatonin Research Articles

Cooling lactating sows exposed to early summer heat wave alters circadian patterns of behavior and rhythms of respiration, rectal temperature, and saliva melatonin.

Heat stress (HS) exerts detrimental effects on animal production, with lactating sows being particularly vulnerable. Understanding the mechanisms involved in HS response could aid in developing effective strategies against the negative impacts on livestock. Recent genome wide association studies identified two core circadian clock genes as potential candidates in mediating HS response. The study aimed to investigate how cooling lactating sows under natural heat stress conditions impacted circadian patterns of respiration rate (RR), rectal temperature (RT), behavior, salivary melatonin and cortisol levels, and diurnal patterns of cytokines in saliva. Mixed parity lactating sows were assigned to one of two treatment groups: electronic cooling pad (C; n = 9) and heat-stressed (H; n = 9). The experiment spanned two 48 h periods of elevated ambient temperatures due to summer heat wave. In the first 48 h period, RR was recorded every 30 min, RT every 60 min, and behaviors (eating, standing, sitting, laying, sleeping, drinking, and nursing) every 5 min. In the second 48 h period, saliva samples were collected every 4 h. Cooling reduced RR and RT and altered circadian patterns (P < 0.05). Cooling did not affect amount of time engaged in any behavior over the 48 h period (P > 0.05), however, daily patterns of eating, standing and laying differed between the treatments (P < 0.05), with altered eating behavior related to RT increment in H sows (P < 0.05). Cooling increased and altered the circadian pattern of salivary melatonin (P < 0.05). Cooling also influenced the diurnal pattern of saliva cytokines. Cooling had no impact on saliva cortisol levels. In conclusion, cooling HS sows impacted circadian rhythms of physiology and behavior, supporting the need for further research to understand if circadian disruption underlies decreased production efficiency of HS animals.

Evaluation of salivary melatonin and MMP-9 levels in periodontal diseases

ObjectiveThe aim of this study was to evaluate salivary matrix metalloproteinase-9 (MMP-9) and melatonin levels in individuals with periodontal health, gingivitis, and periodontitis. DesignA total of 170 participants were enrolled in this study. They included 57 periodontally healthy individuals, 58 gingivitis patients, and 55 periodontitis patients. Saliva samples were collected by passive drool technique. The levels of MMP-9 and melatonin in saliva were measured biochemically using the ELISA method. ResultsSalivary MMP-9 levels in the periodontitis group were significantly higher than those in the gingivitis and periodontally healthy groups, while salivary melatonin levels were significantly lower (p<0.001). A positive correlation was observed between clinical periodontal parameters and salivary MMP-9 levels, while salivary melatonin levels were negatively correlated (p<0.001). A negative correlation was also observed between salivary MMP-9 levels and salivary melatonin levels (p<0.001). ConclusionThis study shows that the level of melatonin in saliva is associated with periodontal disease and with the level of MMP-9 in saliva, which plays a role in this disease.

Comparative evaluation of salivary melatonin levels in patients with bruxism: a case-control study.

Aim: To examine whether there is any difference in the levels of salivary melatonin between bruxism and nonbruxism groups and to compare the stress and anxiety levels between the two groups.Materials & methods: Patients meeting the probable bruxism criteria according to the International Consensus on the Assessment of Bruxism Criteria were included in the bruxism group. The salivary melatonin concentrations of both groups were measured using an ELISA kit. To determine the relationship between stress and bruxism, the State-Trait Anxiety Inventory (STAI) test was used.Results: The bruxism group had a significantly lower night-time salivary melatonin level than the control group (p<0.05). No significant difference was determined between the bruxism group and the control group in respect of the STAI-T scores (p>0.05).Conclusion: The study findings revealed a strong relationship between a low melatonin level and bruxism.

Late Bedtime and Altered Diurnal Axial Length Rhythms of the Eye

Purpose Affecting one-third of the population worldwide and increasing, the sight-threatening condition myopia is causing a significant socio-economic burden. To better understand its etiology, recent studies investigated the role of ocular and systemic rhythms, yet results are conflicting. Here we profiled 24-h variations of axial length of the eye and salivary melatonin concentration in young adults with and without myopia and explored the potential impacts of bedtime on these rhythms. Methods A total of 25 healthy young adults (age 25.0 ± 4.8 years, 13 females) completed this study, including 13 myopes (mean spherical equivalent refractive error −2.93 ± 1.46 diopters) and 12 non-myopes (0.14 ± 0.42 diopters). Saliva sample collection and axial length measurements were repeated for seven times over 24 h starting from 8 am. Information on sleep and chronotype was collected at first visit with the Pittsburgh Sleep Quality Index and the Morningness-Eveningness Questionnaire. Results Significant diurnal rhythms of axial length and salivary melatonin concentration were identified in both refractive groups (both p < 0.001), with no myopia-related rhythm difference (interaction of measurement time-point × myopia, p = 0.9). Late bedtime was associated with altered rhythms (p = 0.009) and smaller diurnal change (p = 0.01) in axial length. Elevated melatonin levels were observed in myopes (p = 0.006) and in late sleepers (p = 0.017). Conclusions These findings suggest that sleep/wake cycles may be involved in the regulation of axial length rhythms. Further research is needed to determine if there exists a causal relationship between the two.

The Nurse-Implemented Chronotherapeutic Bundle in Critically Ill Children, RESTORE Resilience (R 2 ): Pilot Testing in a Two-Phase Cohort Study, 2017-2021.

Pilot test the nurse-led chronotherapeutic bundle in critically ill children, RESTORE Resilience (R 2 ). A two-phase cohort study was carried out from 2017 to 2021. Two similarly sized and organized PICUs in the United States. Children 6 months to 17 years old who were mechanically ventilated for acute respiratory failure. R 2 seven-item chronotherapeutic bundle, including: 1) replication of child's pre-hospital daily routine (i.e., sleep/wake, feeding, activity patterns); 2) cycled day-night light/sound modulation; 3) minimal effective sedation; 4) night fasting with bolus enteral daytime feedings; 5) early progressive mobility; 6) nursing care continuity; and 7) parent diaries. Children underwent environmental (light, sound) and patient (actigraphy, activity log, salivary melatonin, electroencephalogram) monitoring. Parents completed the Child's Daily Routine and Sleep Survey (CDRSS) and Family-Centered Care Scale. The primary outcome was post-extubation daytime activity consolidation (Daytime Activity Ratio Estimate [DARE]). Twenty baseline-phase (2017-2019) and 36 intervention-phase (2019-2021) participants were enrolled. During the intervention phase, nurses used the CDRSS to construct children's PICU schedules. Overall compliance with nurse-implemented R 2 elements 1-5 increased from 18% (interquartile range, 13-30%) at baseline to 63% (53-68%) during the intervention phase ( p < 0.001). Intervention participants were exposed to their pre-hospitalization daily routine ( p = 0.002), cycled day-night light/sound modulation ( p < 0.001), and early progressive mobility on more PICU days ( p = 0.02). Sedation target identification, enteral feeding schedules, and nursing care continuity did not differ between phases. Parent diaries were seldom used. DARE improved during the intervention phase and was higher pre-extubation (median 62% vs. 53%; p = 0.04) but not post-extubation (62% vs. 57%; p = 0.56). In the PICU, implementation of an individualized nurse-implemented chronotherapeutic bundle is feasible. Children who received the R 2 bundle had increased pre-extubation daytime activity consolidation compared to children receiving usual care. Given variation in protocol adherence, further R 2 testing should include interprofessional collaboration, pragmatic trial design, and implementation science strategies.

A Protocol to Determine Circadian Phase by At-Home Salivary Dim Light Melatonin Onset Assessment.

Internal circadian phase assessment is increasingly acknowledged as a critical clinical tool for the diagnosis, monitoring, and treatment of circadian rhythm sleep-wake disorders and for investigating circadian timing in other medical disorders. The widespread use of in-laboratory circadian phase assessments in routine practice has been limited, most likely because circadian phase assessment is not required by formal diagnostic nosologies, and is not generally covered by insurance. At-home assessment of salivary dim light melatonin onset (DLMO, a validated circadian phase marker) is an increasingly accepted approach to assess circadian phase. This approach may help meet the increased demand for assessments and has the advantages of lower cost and greater patient convenience. We reviewed the literature describing at-home salivary DLMO assessment methods and identified factors deemed to be important to successful implementation. Here, we provide specific protocol recommendations for conducting at-home salivary DLMO assessments to facilitate a standardized approach for clinical and research purposes. Key factors include control of lighting, sampling rate, and timing, and measures of patient compliance. We include findings from implementation of an optimization algorithm to determine the most efficient number and timing of samples in patients with Delayed Sleep-Wake Phase Disorder. We also provide recommendations for assay methods and interpretation. Providing definitive criteria for each factor, along with detailed instructions for protocol implementation, will enable more widespread adoption of at-home circadian phase assessments as a standardized clinical diagnostic, monitoring, and treatment tool.

A circadian-informed lighting intervention accelerates circadian adjustment to a night work schedule in a submarine lighting environment.

Night work has detrimental impacts on sleep and performance, primarily due to misalignment between sleep-wake schedules and underlying circadian rhythms. This study tested whether circadian-informed lighting accelerated circadian phase delay, and thus adjustment to night work, compared to blue-depleted standard lighting under simulated submariner work conditions. Nineteen healthy sleepers (12 males; mean±SD aged 29 ±10 y) participated in two separate 8-day visits approximately one month apart to receive, in random order, circadian-informed lighting (blue-enriched and dim, blue-depleted lighting at specific times) and standard lighting (dim, blue-depleted lighting). After an adaptation night (day 1), salivary dim light melatonin onset (DLMO) assessment was undertaken from 18:00-02:00 on days 2-3. During days 3-7, participants completed simulated night work from 00:00-08:00 and a sleep period from 10:00-19:00. Post-condition DLMO assessment occurred from 21:00-13:00 on days 7-8. Ingestible capsules continuously sampled temperature to estimate daily core body temperature minimum (Tmin) time. Tmin and DLMO circadian delays were compared between conditions using mixed effects models. There were significant condition-by-day interactions in Tmin and DLMO delays (both p<0.001). After four simulated night shifts, circadian-informed lighting produced a mean [95%CI] 4.3 [3.3 to 5.4] h greater delay in Tmin timing and a 4.2 [3 to 5.6] h greater delay in DLMO timing compared to standard lighting. Circadian-informed lighting accelerates adjustment to shiftwork in a simulated submariner work environment. Circadian lighting interventions warrant consideration in any dimly lit and blue-depleted work environments where circadian adjustment is relevant to help enhance human performance, safety, and health.

Sleep disturbance in children with attention-deficit hyperactivity disorder: relationship with melatonin and behavior

ABSTRACT Aim To evaluate the prevalence and types of sleep problems and their correlations with melatonin content and behavior in Attention-Deficit Hyperactivity Disorder (ADHD) children. Method Sleep in ADHD children and typically developing children (TD) aged 6–14 was assessed by the Sleep Disorders Scale for Children (SDSC) and actigraphy, salivary melatonin quantified by ELISA, and behavior was analyzed using the Strengths and Difficulties Questionnaire. Results ADHD children showed a higher frequency of sleep disturbances, higher sleep latency, and lower sleep efficiency than in the TD group. The ADHD group presented lower melatonin nocturnal content compared to the TD group. Disorders of Initiating and Maintaining Sleep (DIMS) was moderately associated with nocturnal melatonin. The total behavior difficulties were correlated with Disorders of Initiating and Maintaining Sleep (DIMS), Sleep/Wake Transition Disorders (SWTD), Disorders of Excessive Somnolence (DES), Sleep Hyperhidrosis (SHY) and Total SDSC Score. The behavior was the only determinant of the total SDSC score (R2 = 0.499; p < 0.002). Conclusion This study provides, for the first time, evidence that among the frequent sleep disturbances in ADHD, the disorders in initiating and maintaining sleep are associated with the low levels of melatonin found in this population. Additionally, these, along with other sleep disturbances, are linked to behavioral problems in ADHD.

The dark side of apnea: altered 24-hour melatonin secretion in obstructive sleep apnea (OSAS) is disease severity dependent

PurposeMelatonin aids in the synchronization of the circadian rhythm to the external environment. Few studies have tried to elucidate the relationship between melatonin and obstructive sleep apnea syndrome (OSAS). These often include few patients, do not differentiate between OSAS severity and/or do not analyse a 24-h melatonin profile. This study set out to investigate disease severity dependent differences in 24-h salivary melatonin secretion of OSAS patients compared to a reference population in a retrospective design.Methods24-h salivary melatonin profiles of 169 OSAS patients were analysed (55 light, 66 moderate, 48 severe) as well as 91 reference patients. Several aspects of the melatonin curve were analysed and stratified according to OSAS severity. Parameters included: dim light melatonin onset (DLMO), time of returning below DLMO (DLMOoff), peak melatonin concentration and time, and total melatonin exposure.ResultsSignificant effects were corrected for confounding by age and sex using linear regression. Our analysis shows that, compared to reference and in a disease dependent manner, OSAS patients have a significantly lower 24-h melatonin curve, lower melatonin peak concentration, lower total melatonin exposure and a smaller proportion of patients reach DLMO. The differences in peak melatonin production and total melatonin exposure were resistant to confounding by age and/or sex.ConclusionThis study describes clear OSAS severity dependent abnormalities in melatonin production in OSAS patients, independent of sex and/or age. Future research should indicate whether oral melatonin supplementation has beneficial effects in OSAS patients with attenuated endogenous melatonin production.

Exogenous melatonin's effect on salivary cortisol and amylase: A randomized controlled trial.

This study aimed to examine the effect of acute exogenous melatonin administration on salivary cortisol and alpha-amylase (sCort and sAA) as representatives of the HPA axis and the sympathetic nervous system, respectively. A single-dose prolonged-release melatonin (2 mg) or a placebo tablet was given to healthy volunteers (n = 64) at 20:00 h in a crossover design. The saliva was collected at six time points (20:00, 21:00, awakening, 30 min after awakening, 10:00, and 12:00 h) and was measured for sCort, sAA, and salivary melatonin (sMT) levels. Pulse rates and sleep parameters were also collected. Melatonin was effective in improving sleep onset latency by 7:04 min (p = .037) and increasing total sleep time by 24 min (p = .006). Participants with poor baseline sleep quality responded more strongly to melatonin than participants with normal baseline sleep quality as they reported more satisfaction in having adequate sleep (p = .017). Melatonin administration resulted in higher sCort levels at awakening time point (p = .023) and a tendency of lower sAA levels but these were not significant. Melatonin ingestion at 20:00 h resulted in a marked increase in sMT levels at 21:00 h and remained higher than baseline up to at least 10:00 h (p < .001). Melatonin increases sCort levels at certain time point with a tendency to lower sAA levels. These opposing effects of melatonin suggested a complex interplay between melatonin and these biomarkers. Also, the results confirmed the positive acute effect of a single-dose melatonin on sleep quality.

Lower Melatonin Indicates Poor Short-term Prognosis in Patients with Acute Ischemic Stroke.

We evaluated endogenous melatonin levels in the acute phase of cerebral infarction and explored the impact of possible changes in melatonin levels on the prognosis of patients. This study recruited acute ischemic stroke (AIS) patients from the Department of the Second Affiliated Hospital of Soochow University between December 2019 and June 2021, along with healthy control subjects. Salivary melatonin samples were collected from each participant between 7 pm and 10 pm, and fasting plasma was collected the following morning to measure the levels of inflammatory markers. The prognosis was assessed through follow-up three months after discharge. The relationship between melatonin levels and plasma inflammatory markers was assessed, followed by an analysis of the effect of melatonin levels on patient prognosis. The study enrolled a total of 160 participants, including 120 AIS patients aged 50 years or older (61.7% male) and 40 age-matched controls (55.0% male). The AIS group exhibited lower salivary melatonin levels at 19 (P = 0.002), 20 (P < 0.001), 21 (P < 0.001), and 22 (P < 0.001) o'clock, and the average melatonin level was also lower (P < 0.001). Logistic regression analysis models indicated an association between low melatonin levels and poor prognosis. Salivary melatonin levels demonstrated good predictive ability for the prognosis of AIS patients. Melatonin levels were lower in AIS patients compared to controls. In addition, lower melatonin levels were associated with a poorer prognosis among AIS patients.

0398 Impact of an Over-The-Counter "Sleep Lotion" on Salivary Melatonin Levels and Sleep Quality

0398 Impact of an Over-The-Counter "Sleep Lotion" on Salivary Melatonin Levels and Sleep Quality

Alteration of circadian sleep-wake rhythm and salivary melatonin secretion in idiopathic/isolated REM sleep behavior disorder: Preliminary evidence

Objective/BackgroundIdiopathic/isolated REM sleep behavior disorder (iRBD) is widely regarded as an early sign of neurodegeneration leading to synucleinopathies. While circadian rhythm alterations in iRBD have been preliminarily demonstrated, evidence on melatonin secretion patterns in this clinical condition is limited. To address this knowledge gap, this exploratory study aimed to integrate salivary melatonin measurement with actigraphic monitoring in individuals with iRBD and age-matched healthy controls (HC) under real-life conditions. MethodsParticipants diagnosed with iRBD and HC underwent clinical evaluation and wore an actigraph for seven days and nights. Salivary melatonin concentrations were measured at five time points during the last night of recording. Comparative analyses were conducted on clinical data, actigraphic parameters, and melatonin levels between the two groups. ResultsiRBD participants (n = 18) showed greater motor (p < 0.01) and non-motor symptoms (p < 0.001), alongside disruptions in circadian sleep-wake rhythm compared to HC (n = 10). Specifically, actigraphy revealed a delayed central phase measurement (p < 0.05), reduced activity during the most active hours (p < 0.001), and decreased relative amplitude (p < 0.05). Total salivary melatonin concentration was significantly lower in iRBD (p < 0.05), with a slight but non-significant phase delay in dim light melatonin onset. ConclusionsThis exploratory study highlights a dysregulation of circadian sleep-wake rhythm coupled with reduced melatonin secretion in iRBD. Future research could add to these preliminary findings to evaluate novel treatment approaches to regulate the sleep-wake cycle and elucidate the implications of circadian dysregulation in the conversion from iRBD to neurodegeneration.

Sleep Disturbance During Post-Traumatic Amnesia and Early Recovery After Traumatic Brain Injury.

After moderate to severe traumatic brain injury (TBI), sleep disturbance commonly emerges during the confused post-traumatic amnesia (PTA) recovery stage. However, the evaluation of early sleep disturbance during PTA, its recovery trajectory, and influencing factors is limited. This study aimed to evaluate sleep outcomes in patients experiencing PTA using ambulatory gold-standard polysomnography (PSG) overnight and salivary endogenous melatonin (a hormone that influences the sleep-wake cycle) assessment at two time-points. The relationships between PSG-derived sleep-wake parameters and PTA symptoms (i.e., agitation and cognitive disturbance) were also evaluated. In a patient subset, PSG was repeated after PTA had resolved to assess the trajectory of sleep disturbance. Participants with PTA were recruited from Epworth HealthCare's inpatient TBI Rehabilitation Unit. Trained nurses administered overnight PSG at the patient bedside using the Compumedics Somté portable PSG device (Compumedics, Ltd., Australia). Two weeks after PTA had resolved, PSG was repeated. On a separate evening, two saliva specimens were collected (at 24:00 and 06:00) for melatonin testing. Results of routine daily hospital measures (i.e., Agitated Behavior Scale and Westmead PTA Scale) were also collected. Twenty-nine patients were monitored with PSG (mean: 41.6 days post-TBI; standard deviation [SD]: 28.3). Patients' mean sleep duration was reduced (5.6 h, SD: 1.2), and was fragmented with frequent awakenings (mean: 27.7, SD: 15.0). Deep, slow-wave restorative sleep was reduced, or completely absent (37.9% of patients). The use of PSG did not appear to exacerbate patient agitation or cognitive disturbance. Mean melatonin levels at both time-points were commonly outside of normal reference ranges. After PTA resolved, patients (n = 11) displayed significantly longer mean sleep time (5.3 h [PTA]; 6.5 h [out of PTA], difference between means: 1.2, p = 0.005). However, disturbances to other sleep-wake parameters (e.g., increased awakenings, wake time, and sleep latency) persisted after PTA resolved. This is the first study to evaluate sleep disturbance in a cohort of patients as they progressed through the early TBI recovery phases. There is a clear need for tailored assessment of sleep disturbance during PTA, which currently does not form part of routine hospital assessment, to suggest new treatment paradigms, enhance patient recovery, and reduce its long-term impacts.

An LC-MS/MS-based method for the simultaneous quantification of melatonin, cortisol and cortisone in saliva

Disturbances in the diurnal pattern are associated with several clinical and psychological conditions, including depression and fatigue. Salivary sampling for melatonin, cortisol and cortisone provides a non-invasive method for frequent sampling and obtaining biochemical insight into the diurnal pattern of individuals. Therefore, a new liquid chromatography-tandem mass spectrometry-based method for the measurement of salivary melatonin, cortisol and cortisone was developed and validated. The method required 250 μl saliva, used isotope dilution methodology and was based on a liquid-liquid extraction for sample preparation, reversed-phase chromatography and multiple reaction monitoring on a mass spectrometer for quantitation. The lower limits of quantification obtained were 0.010 nmol/L for melatonin, 0.5 nmol/L for cortisol and 1.00 nmol/L for cortisone and the limits of detection were 0.003 nmol/L, 0.15 nmol/L and 0.1 nmol/L respectively. The method imprecision was ≤14% for all measurands, and the method comparison showed highly comparable results with high correlation coefficients (all ≥0.964). Potential interference of cortisol and cortisone by prednisolone was observed and could be detected by chromatogram review. Typical diurnal patterns for melatonin, cortisol and cortisone were observed in the saliva of 20 cancer survivors who collected saliva throughout the day.

Correlation of Circadian Rhythms and Improvement of Depressive Symptoms in Acute Ischemic Stroke Patients

To investigate the correlation between evening melatonin timing secretion, dim light melatonin onset (DLMO), and post-stroke depression (PSD) in acute ischemic stroke patients and their influence on the improvement of depressive symptoms. 120 patients with a recent magnetic resonance imaging confirmed stroke were included. Salivary melatonin samples were collected at 5 time points within 1 week after hospitalization (7 p.m.-11 p.m., 1 sample per hour). The circadian phase was defined by calculating DLMO secretion. Post-stroke depressive symptoms were evaluated by the 17-item Hamilton Rating Scale for Depression (HRSD) both on day 7 of hospitalization and 3 months after stroke. Patients were divided into PSD and non-PSD groups based on whether the acute phase HRSD score was ≥8. Similarly, patients were divided into the improved depressive symptoms (IDS) and no improvement in depressive symptoms (non-IDS) groups based on whether the HRSD score at 3 months was lower than at baseline. Neurological recovery at 3 months was assessed using the modified Rankin Scale (mRS). The difference in DLMO between PSD and non-PSD patients was not statistically significant (p =0.173). In the non-IDS group, there was a significant decrease in melatonin secretion at 10 p.m. (p =0.012), and DLMO was significantly later than in the IDS group (p =0.017). Logistic regression analysis showed that DLMO (OR 1.91, 95%CI:1.13-3.23, p = 0.016) was an independent risk factor for persistent no improvement in depressive symptoms, which was associated with a markedly worse prognosis (p <.001). Our findings suggest possible interventions for the very early identification of non-IDS patients.

Stress and sleep deprivation-related biomarkers in saliva in patients with retinitis pigmentosa.

Patients with Retinitis Pigmentosa (RP) commonly experience sleep-related issues and are susceptible to stress. Moreover, variatiaons in their vision are often linked to anxiety, stress and drowsiness, indicating that stress and sleep deprivation lead to a decline in vision, and vision improves when both are mitigated. The objective of this study was to investigate the utility of salivary biomarkers as biochemical indicators of anxiety and sleep deprivation in RP patients. Seventy-eight RP patients and 34 healthy controls were included in this observational study. Anxiety and sleep-quality questionnaires, a complete ophthalmological exam for severity grading and, the collection of salivary samples from participants were assessed for participants. The activity of biomarkers was estimated by ELISA, and statistical analysis was performed to determine associations between the parameters. Associations between underlying psychological factors, grade of disease severity, and biomarkers activity were also examined. Fifty-two (67%) of patients had a severe RP, and 26 (33%) had a mild-moderate grade. Fifty-eight (58,9%) patients reported severe levels of anxiety and 18 (23.,1%) a high level. Forty-six (59%) patients obtained pathological values in sleep-quality questionaries and 43 (55.1%) in sleepiness. Patients with RP exhibited significant differences in testosterone, cortisol, sTNFαRII, sIgA and melatonin as compared to controls and patients with a mild-moderate and advanced stage of disease showed greater differences. In covariate analysis, patients with a severe anxiety level also showed greater differences in mean salivary cortisol, sTNFαRII and melatonin and male patients showed lower IgA levels than female. The present findings suggest that salivary biomarkers could be suitable non-invasive biochemical markers for the objective assessment of sleep deprivation and anxiety in RP patients. Further research is needed to characterize the effects of untreated negative psychological states and sleep deprivation on increased variability of vision and disease progression, if any.

Role of salivary and plasma melatonin levels in oral squamous cell carcinoma

Objectives: The present research aims to look into the variations in levels of plasma and saliva melatonin with the sleep-wake cycle in healthy individuals and its correlation with the levels in oral squamous cell carcinoma (OSCC) patients and to explore the possibility of the use of plasma and saliva, as reliable, minimally-invasive/ non-invasive, and biofluids for measuring the levels of melatonin as biomarkers for the diagnosis of OSCC. Material and Methods: This comparative case–control prospective study was conducted on histopathologically proven 10 patients suffering from OSCC (Group II) and 10 healthy individuals (Group I) belonging to the age group of 25–65 years. The antecubital fossa region was used to draw peripheral venous blood, which was then centrifuged, and the plasma was kept at −200C. Using the passive drool technique, approximately 5 mL of unstimulated saliva samples were obtained, and the samples were kept at −200C. Both the samples were assayed as early as possible. Results: The result obtained was that the salivary and plasma melatonin levels were much higher during evening hours than morning interval in the healthy group (Group I). A similar trend was shown in Group II, compared to patients with OSCC, healthy patients have much higher levels of melatonin in their saliva and plasma. Conclusion: Hence, we conclude that the evaluation of the salivary melatonin level of patients suffering from OSCC may be considered reliable as well as non-invasive methods in the early diagnosis of OSCC. Saliva may be considered more advantageous over plasma for being non-invasive, less technique sensitive procedure, and having good patient compliance.

Salivary Cortisol and Melatonin, Sleep, and Behavioral Patterns in Older Adults Living With Dementia.

Over half of the older adults living with dementia have behavioral and psychological symptoms of dementia (BPSD), including sleep disturbance; however, little is known about physiological markers. Salivary cortisol and melatonin have been identified as potential biomarkers of BPSD, with evidence suggesting a relationship between these biomarkers and various behavioral factors, as well as sleep and activity patterns. The aim of this study was to investigate the time-dependent changes in salivary cortisol and melatonin levels in older adults with dementia, their relationship with the sleep-wake cycle, and their correlation with BPSD symptoms and behavioral factors. This observational study conducted in Seoul and Gyeonggi-do, South Korea, used data from 172 older adults with dementia, measuring sleep and activity patterns for 2 weeks using a wearable device, in addition to administering questionnaires for neuropsychiatric and psychological symptoms-the Neuropsychiatric Inventory, Cohen-Mansfield Agitation Inventory, and Cornell Scale for Depression in Dementia. Salivary cortisol and melatonin levels were measured at four time points and divided into four groups based on a dual-trajectory model. Differences among the groups were analyzed using one-way analysis of variance. The participants showed normal but heterogeneous patterns of salivary cortisol and melatonin levels. Dual-trajectory pattern analysis showed that higher levels of melatonin during the daytime were correlated with poor nighttime sleep efficiency and decreased disinhibited behaviors, and higher levels of cortisol at all four time points were associated with decreased physical activity. Measuring and analyzing periodic changes in cortisol and melatonin levels can predict various behavioral symptoms (e.g., sleep disturbances, activity counts, and disinhibition) in older adults with dementia. A study with an experimental design is needed to discover the direct physiological interactions between cortisol, melatonin, and these symptoms.

An independent comparison of the Novolytix salivary melatonin radioimmunoassay with the new Novolytix salivary melatonin enzyme-linked immunosorbent assay.

The dim light melatonin onset (DLMO) is the current gold standard biomarker of the timing of the central circadian clock in humans and is often assessed from saliva samples. To date, only one commercially available salivary melatonin assay is considered accurate at the low daytime levels required to accurately detect the DLMO (Novolytix RIA RK-DSM2). The aim of this study was to conduct the first independent evaluation of a newly improved enzyme-linked immunosorbent assay (ELISA; Novolytix MLTN-96) and compare it with the recommended radioimmunoassay (RIA)-both in terms of melatonin concentrations and derived DLMOs. Twenty participants (15 females, 18-59 years old) provided saliva samples every 30 min in dim light starting 6 h before their habitual bedtime, yielding a total of 260 saliva samples. Both the RIA and ELISA yielded daytime melatonin concentrations <2 pg/mL, indicating adequate accuracy to detect the DLMO. The melatonin concentrations from the two assays were highly correlated (r = .94, p < .001), although the RIA yielded lower levels of melatonin concentration than the ELISA, on average by 0.70 pg/mL (p = .006). Seventeen DLMOs were calculated from the melatonin profiles and the DLMOs from both assays were not statistically different (p = .36) and were highly correlated (r = .97, p < .001). Two DLMOs derived from the RIA occurred more than 30 min earlier than the DLMO derived from the ELISA. These results indicate that the new Novolytix ELISA is an appropriate assay to use if the Novolytix RIA is not feasible or available.