lemon balm, sleep, Alzheimer's, locus coeruleus, REM behavior disorder - brief notes

 Lemon balm (Melissa officinalis) was found to improve sleep in a fly model of Alzheimer's disease.


Screening of sleep assisting drug candidates with a Drosophila model (2020)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7390450/

 

"Overall, female flies were more vulnerable to DD stimulation considering total sleep time, but not in the sleep frequency. Therefore, female flies were chosen for the following drug screening study.

...

the administration of melatonin shortened sleep latency but did not increase the total sleep time during sleep deprivation (Fig 4A, 4B and 4F), indicating that melatonin may only induce flies to sleep faster but not longer. Such results are consistent with human clinical trials that have reported that the prescription of melatonin helps induce sleep but does not enhance total sleep time []. Moreover, the activity index shows no change after melatonin treatment (Fig 4G), suggesting that melatonin has a limited effect on activity during wake time.

...

For instance, the treatment of P. notoginseng can increase total sleep in control flies but not in AD; while the extract from M. officinalis has limited effects on control flies but greatly enhances total sleep time in AD."

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Impaired cerebral microcirculation in isolated REM sleep behaviour disorder (2021)

https://academic.oup.com/brain/advance-article/doi/10.1093/brain/awab054/6242260



"During the prodromal period of Parkinson’s disease and other α-synucleinopathy-related parkinsonisms, neurodegeneration is thought to progressively affect deep brain nuclei, such as the locus coeruleus, caudal raphe nucleus, substantia nigra, and the forebrain nucleus basalis of Meynert. Besides their involvement in the regulation of mood, sleep, behaviour, and memory functions, these nuclei also innervate parenchymal arterioles and capillaries throughout the cortex, possibly to ensure that oxygen supplies are adjusted according to the needs of neural activity. The aim of this study was to examine whether patients with isolated REM sleep behaviour disorder, a parasomnia considered to be a prodromal phenotype of α-synucleinopathies, reveal microvascular flow disturbances consistent with disrupted central blood flow control.
...

The locus coeruleus has long been implicated as a component of neurodegeneration in both Parkinson’s and Alzheimer’s diseases.19 Previous studies using neuromelanin sensitive MRI have reported significant reductions in the locus coeruleus hyperintensity signal in iRBD patients, suggesting that neuronal damage is present in these patients.52,53 Animal studies suggest that noradrenergic fibres from the locus coeruleus play a key role in providing trophic support for both astrocytes and neurons, and in suppressing inflammation and oxidative stress.19 Control of microvascular flow by the noradrenergic locus coeruleus might provide part of this trophic support by helping to match oxygen availability to cellular oxidative phosphorylation in brain tissue. The locus coeruleus also plays a key role in maintaining blood–brain barrier integrity.54 "

See also previous post on locus coeruleus


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Safety and efficacy of Melissa officinalis extract containing rosmarinic acid in the prevention of  Alzheimer’s disease progression (2020)

https://www.nature.com/articles/s41598-020-73729-2.pdf

"No differences in vital signs or physical and neurologic examination results were detected between the M. officinalis and placebo groups. No serious adverse events occurred. There were no significant differences in cognitive measures; however, the mean Neuropsychiatric Inventory Questionnaire (NPI‑Q) score improved by 0.5 points in the M. officinalisgroup and worsened by 0.7 points in the placebo group between the baseline and 24‑week visit, indicating a significant difference (P = 0.012). No significant differences were apparent in disease‑related biomarkers between the groups. M. officinalis extract containing 500 mg of RA taken daily was safe and well‑tolerated by patients with mild dementia due to AD.

The mean NPI-Q scores improved by 0.5 points in the M. officinalis group and worsened by 0.7 points in the placebo group between baseline and the 24-week visit. On further analyzing each NPI-Q subscale, time × treatment variable of “Irritability/Lability” was signifi-cant (F = 4.539, P = 0.006); the mean scores of “Irritability/Lability” improved by 0.32 points in the M. officinalisgroup and worsened by 0.23 points in the placebo group between baseline and the 24-week visit."

No mention of sleep; the NPI-Q has a question regarding 'Nightime behavior' - 'Does the patient awaken you during the night, rise too early in the morning, or take excessive naps during the day?'

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