1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine improves cognitive decline by enhancing long-term depression

Unlocking choline's potential in Alzheimer's disease: A narrative review exploring the neuroprotective and neurotrophic role of phosphatidylcholine and assessing its impact on memory and learning

BACKGROUND AND AIMS

Growing evidence suggests nutritional intervention may influence the development and progression of Alzheimer's Disease (AD). Choline, an essential dietary nutrient plays a critical role in neurological development and brain function, however, its effects on AD in humans is unclear. The research aims to investigate mechanistic links between dietary choline intake and cognitive functioning, focusing on the role of phosphatidylcholine (PC) in neuroplasticity and its interaction with amyloid beta (Aβ) peptides in neuron membranes. Additionally, human evidence on the potential benefits of PC interventions on AD, cognition, and proposed mechanisms are evaluated.

METHODS

A reproducible systematic literature search was performed using a three-tranche strategy, consisting of a review, mechanism, and intervention search. Using PubMed as the main database, 1254 titles and abstracts were screened, 149 papers were read in full and 65 peer-reviewed papers were accepted, critically appraised, and analysed in a narrative review.

RESULTS

Predominantly preclinical evidence demonstrated that PC enhances neuroplasticity, a key biological substrate for cognition, by activating intracellular neuronal signalling pathways or through neuron membrane function. Molecular dynamic simulation methods provided a mechanistic understanding of the interconnection between neuronal PC content and the potential behaviour and trajectory of Aβ peptide aggregation. The results indicate that the neuronal membrane composition of PC is critical to inhibiting Aβ aggregation and neuronal damage, protecting the neuron from Aβ toxicity. This might provide a foundation for optimising cellular PC which may prove beneficial in the treatment or prevention of neurodegenerative disease. Altered PC metabolism in AD was evidenced in observational studies; however, whether this relationship represents a cause or consequence of AD remains to be determined. Human intervention studies did not produce conclusive evidence supporting its effectiveness in enhancing cognitive function. This lack of consistency primarily stems from methodological constraints within the conducted studies. Human observational research provided the most compelling evidence linking a higher dietary PC intake to a reduced risk of dementia and significant improvements in cognitive testing.

CONCLUSION

Despite the lack of randomised control trials (RCTs) assessing the efficacy of lecithin/PC to improve cognition in AD patients, there exists promising evidence supporting its neuroprotective and neurotrophic role. This review establishes an evidence-based framework through chains of mechanistic evidence, that may provide potential strategies for enhanced neuroprotection and reduced neurodegeneration caused by AD. Considering the escalating global burden of AD and the current shortcomings in effective treatments, this review together with the limitations and gaps identified in the existing research presents valuable insights that emphasise the urgency of more comprehensive research into the relationship between PC and AD.

Sex Modifies the Impact of Type 2 Diabetes Mellitus on the Murine Whole Brain Metabolome

Type 2 diabetes mellitus (T2DM) leads to the development of cardiovascular diseases, cognitive impairment, and dementia. There are sex differences in the presentation of T2DM and its associated complications. We sought to determine the impact of sex and T2DM on the brain metabolome to gain insights into the underlying mechanisms of T2DM-associated cognitive complications. Untargeted metabolomic analysis was performed, using liquid chromatography-mass spectrometry, on whole brain tissue from adult male and female db/db mice (a T2DM model) compared to wild-type (WT) C57Bl6/J mice. Regardless of sex, T2DM increased free fatty acids and decreased acylcarnitines in the brain. Sex impacted the number (103 versus 65 in males and females, respectively), and types of metabolites shifted by T2DM. Many choline-containing phospholipids were decreased by T2DM in males. Female-specific T2DM effects included changes in neuromodulatory metabolites (γ-aminobutyric acid, 2-linoleoyl glycerol, N-methylaspartic acid, and taurine). Further, there were more significantly different metabolites between sexes in the T2DM condition as compared to the WT controls (54 vs. 15 in T2DM and WT, respectively). T2DM alters the murine brain metabolome in both sex-independent and sex-dependent manners. This work extends our understanding of brain metabolic sex differences in T2DM, cognitive implications, and potential sex-specific metabolic therapeutic targets.

Glycerophospholipid Supplementation as a Potential Intervention for Supporting Cerebral Structure in Older Adults

Modifying nutritional intake through supplementation may be efficacious for altering the trajectory of cerebral structural decline evident with increasing age. To date, there have been a number of clinical trials in older adults whereby chronic supplementation with B vitamins, omega-3 fatty acids, or resveratrol, has been observed to either slow the rate of decline or repair cerebral tissue. There is also some evidence from animal studies indicating that supplementation with glycerophospholipids (GPL) may benefit cerebral structure, though these effects have not yet been investigated in adult humans. Despite this paucity of research, there are a number of factors predicting poorer cerebral structure in older humans, which GPL supplementation appears to beneficially modify or protect against. These include elevated concentrations of homocysteine, unbalanced activity of reactive oxygen species both increasing the risk of oxidative stress, increased concentrations of pro-inflammatory messengers, as well as poorer cardio- and cerebrovascular function. As such, it is hypothesized that GPL supplementation will support cerebral structure in older adults. These cerebral effects may influence cognitive function. The current review aims to provide a theoretical basis for future clinical trials investigating the effects of GPL supplementation on cerebral structural integrity in older adults.

Preparation and Evaluation of Phospholipid-Based Complex of Standardized Centella Extract (SCE) for the Enhanced Delivery of Phytoconstituents

In the present study, a phospholipid-based complex of standardized Centella extract (SCE) was developed with a goal of improving the bioavailability of its phytoconstituents. The SCE-phospholipid complex was prepared by solvent evaporation method and characterized for its physicochemical and functional properties. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), photomicroscopy, and powder x-ray diffraction (PXRD) were used to confirm the formation of Centella naturosome (CN). The prepared complex was functionally evaluated by apparent solubility, in vitro drug release, ex vivo permeation, and in vivo efficacy studies. The prepared CN exhibited a significantly higher (12-fold) aqueous solubility (98.0 ± 1.4 μg/mL), compared to the pure SCE (8.12 ± 0.44 μg/mL), or the physical mixture of SCE and the phospholipid (13.6 ± 0.4 μg/mL). The in vitro dissolution studies revealed a significantly higher efficiency of CN in releasing the SCE (99.2 ± 4.7, % w/w) in comparison to the pure SCE (39.2 ± 2.3, % w/w), or the physical mixture (42.8 ± 2.09, % w/w). The ex vivo permeation studies with the everted intestine method showed that the prepared CN significantly improved the permeation of SCE (82.8 ± 3.7, % w/w), compared to the pure SCE (26.8 ± 2.4, % w/w), or the physical mixture (33.0 ± 2.7, % w/w). The in vivo efficacy studies using the Morris Water Maze test indicated a significant improvement of the spatial learning and memory in aged mice treated with CN. Thus, drug-phospholipid complexation appears to be a promising strategy to improve the aqueous solubility and bioavailability of bioactive phytoconstituents.

Anti-depressant effects of Xiaoyaosan on rat model of chronic unpredictable mild stress: a plasma metabonomics study based on NMR spectroscopy

OBJECTIVES

To investigate the antidepressant effects of Xiaoyaosan (XYS) in a chronic unpredictable mild stress (CUMS) depression model.

METHODS

The changes in behaviour and plasma metabolic profiles were investigated after four-week CUMS exposure and treatment. Drugs were administered during the four-week period of CUMS, with the healthy group serving as negative controls, and the fluoxetine and venlafaxine groups serving as positive controls. Plasma samples were collected at 28th day, and the plasma metabolic profiling was measured using NMR, followed by multivariate analysis.

KEY FINDINGS

Exposure to CUMS for four weeks caused depression-like behaviour in rats, as indicated by significant decreases in weight gain, sucrose consumption and locomotor activity. Eleven potential biomarkers, including seven in the Carr-Purcell-Meiboom-Gill spectra, five in the diffusion-edited spectra, and one in both were identified. It was found that trimethylamine-N-oxide, alanine, β-hydroxybutyrate, valine, leucine/isoleucine, low-density lipoprotein/very low-density lipoprotein and lipids were lower and phosphatidylcholine, high-density lipoprotein, choline and N-acetyl glycoproteins were higher in CUMS-treated rats, as compared with controls. XYS significantly suppressed behavioural changes and attenuated plasma metabolite changes.

CONCLUSIONS

XYS produced an obvious antidepressant effect, and the metabonomic approach benefits estimation of the pharmacodynamic action of traditional Chinese medicine prescriptions.

DL- and PO-phosphatidylcholines as a promising learning and memory enhancer

In the water maze test, oral administration with 1,2-dilynoleoyl-sn-glycero-3-phosphocholine (DLPhtCho)(5 mg/kg) alone or DLPhtCho (5 mg/kg) plus 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPhtCho)(5 mg/kg) significantly shortened the prolonged acquisition latency for rats intraperitoneally injected with scopolamine, with more efficient effect than (POPhtCho)(5 mg/kg) alone, arachidonic acid (AA)(5 mg/kg) alone, docosahexaenoic acid (DHA)(5 mg/kg) alone, or 1-palmitoyl-2-linoleil-sn-glycero-3-phosphoserine (PLPhtSer)(5 mg/kg) alone. POPhtCho (5 mg/kg) alone or DLPhtCho (5 mg/kg) plus POPhtCho (5 mg/kg) also significantly shortened the prolonged retention latency for rats intraperitoneally injected with scopolamine, but otherwise no significant effect was obtained with DLPhtCho (5 mg/kg) alone, AA (5 mg/kg) alone, DHA (5 mg/kg) alone, or PLPhtSer (5 mg/kg) alone. Oral co-administration with DLPhtCho (5 mg/kg) and POPhtCho (5 mg/kg) significantly shortened the acquisition latency for rats untreated with scopolamine as compared with the latency for administration with polyethylene glycol (PEG), DLPhtCho alone at doses of 5 and 10 mg/kg, or POPhtCho alone at doses of 5 and 10 mg/kg, while no efficient effect on the retention latency was obtained. To assess the effect of DLPhtCho and POPhtCho on cognitive functions for humans, Mini Mental State Examination (MMSE) test was performed in subjects with cognitive disorders (the average MMSE score, 15). Oral co-intake with DLPhtCho (50 mg) and POPhtCho (45 mg) once after breakfast everyday raised the score to over 20, corresponding to normal cognitive functions, throughout 5 months after intake, and the increase in the score was significantly greater than that for oral intake with DLPhtCho (100 mg/day) alone or POPhtCho (90 mg/kg) alone. Taken together, the results of the present study show that co-intake with DLPhtCho and POPhtCho could enhance learning and memory ability and improve cognitive disorders for both the animals and humans with a promising efficacy.

1,2-dilinoleoyl-sn-glycero-3-phosphoethanolamine ameliorates age-related spatial memory deterioration by preventing neuronal cell death

BACKGROUND

Accumulating evidence has pointed that a variety of lipids could exert their beneficial actions against dementia including Alzheimer disease and age-related cognitive decline via diverse signaling pathways. Endoplasmic reticulum (ER) stress-induced neuronal apoptosis, on the other hand, is a critical factor for pathogenesis of neurodegenerative diseases such as Alzheimer disease and Parkinson disease, senile dementia, and ischemic neuronal damage. The present study examined the effects of 1,2-dilinoleoyl-sn-glycero-3-phosphoethanolamine (DLPhtEtn), a phospholipid, on ER stress-induced neuronal death and age-related cognitive disorders.

METHODS

PC-12 cell viability was assayed before and after treatment with amyloid-β(1-40) peptide or thapsigargin in the presence and absence of DLPhtEtn. A series of behavioral tests were performed for senescence-accelerated mouse-prone 8 (SAMP8) mice after 7-month oral administration with polyethylene glycol (PEG) or DLPhtEtn and then, the number of hippocampal neurons was counted.

RESULTS

Amyloid-β(1-40) peptide or thapsigargin is capable of causing ER stress-induced apoptosis. DLPhtEtn (30 μM) significantly inhibited PC-12 cell death induced by amyloid-β(1-40) peptide or thapsigargin. In the water maze test, oral administration with DLPhtEtn (1 mg/kg) for 7 months (three times a week) significantly shortened the prolonged retention latency for SAMP8 mice. In contrast, DLPhtEtn had no effect on the acquisition and retention latencies in both the open field test and the passive avoidance test for SAMP8 mice. Oral administration with DLPhtEtn (1 mg/kg) for 7 months prevented a decrease in the number of hippocampal neurons for SAMP8 mice.

CONCLUSION

The results of the present study show that DLPhtEtn ameliorates age-related spatial memory decline without affecting motor activities or fear memory, possibly by protecting hippocampal neuronal death. DLPhtEtn, thus, might exert its beneficial action against senile dementia and neurodegenerative diseases such as Alzheimer disease.