Phosphatidylserine for the Treatment of Pediatric Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis

Phosphatidylserine: A Novel Target for Ischemic Stroke Treatment

Over the past 40 years, research has heavily emphasized stroke treatments that directly target ischemic cascades after stroke onset. Much attention has focused on studying neuroprotective drugs targeting one aspect of the ischemic cascade. However, the single-target therapeutic approach resulted in minimal clinical benefit and poor outcomes in patients. Considering the ischemic cascade is a multifaceted and complex pathophysiological process with many interrelated pathways, the spotlight is now shifting towards the development of neuroprotective drugs that affect multiple aspects of the ischemic cascade. Phosphatidylserine (PS), known as the "eat-me" signal, is a promising candidate. PS is involved in many pathophysiological changes in the central nervous system after stroke onset, including apoptosis, inflammation, coagulation, and neuronal regeneration. Moreover, PS might also exert various roles in different phases after stroke onset. In this review, we describe the synthesis, regulation, and function of PS under physiological conditions. Furthermore, we also summarize the different roles of PS after stroke onset. More importantly, we also discuss several treatment strategies that target PS. We aim to advocate a novel stroke care strategy by targeting PS through a translational perspective.

Phosphatidylserine: A comprehensive overview of synthesis, metabolism, and nutrition

Phosphatidylserine (PtdS) is classified as a glycerophospholipid and a primary anionic phospholipid and is particularly abundant in the inner leaflet of the plasma membrane in neural tissues. It is synthesized from phosphatidylcholine or phosphatidylethanolamine by exchanging the base head group with serine, and this reaction is catalyzed by PtdS synthase-1 and PtdS synthase-2 located in the endoplasmic reticulum. PtdS exposure on the outside surface of the cell is essential for eliminating apoptotic cells and initiating the blood clotting cascade. It is also a precursor of phosphatidylethanolamine, produced by PtdS decarboxylase in bacteria, yeast, and mammalian cells. Furthermore, PtdS acts as a cofactor for several necessary enzymes that participate in signaling pathways. Beyond these functions, several studies indicate that PtdS plays a role in various cerebral functions, including activating membrane signaling pathways, neuroinflammation, neurotransmission, and synaptic refinement associated with the central nervous system (CNS). This review discusses the occurrence of PtdS in nature and biosynthesis via enzymes and genes in plants, yeast, prokaryotes, mammalian cells, and the brain, and enzymatic synthesis through phospholipase D (PLD). Furthermore, we discuss metabolism, its role in the CNS, the fortification of foods, and supplementation for improving some memory functions, the results of which remain unclear. PtdS can be a potentially beneficial addition to foods for kids, seniors, athletes, and others, especially with the rising consumer trend favoring functional foods over conventional pills and capsules. Clinical studies have shown that PtdS is safe and well tolerated by patients.

Polar Lipids Supplementation Enhances Basal Excitatory Synaptic Transmission in Primary Cortical Neuron

SCOPE

Polar lipids, such as gangliosides and phospholipids, are fundamental structural components that play critical roles in the development and maturation of neurons in the brain. Recent evidence has demonstrated that dietary intakes of polar lipids in early life are associated with improved cognitive outcomes during infancy and adolescence. However, the specific mechanisms through which these lipids impact cognition remain unclear.

METHODS AND RESULTS

This study examines the direct physiological impact of polar lipid supplementation, in the form of buttermilk powder, on primary cortical neuron growth and maturation. The changes are measured with postsynaptic current response recordings, immunohistochemical examination of functional synapse localization and numbers, and the biochemical quantification of receptors responsible for neuronal synaptic neurotransmission. Chronic exposure to polar lipids increases primary mouse cortical neuron basal excitatory synapse response strength attributed to enhanced dendritic complexity and an altered expression of the excitatory α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit 2 (GluR2).

CONCLUSION

The present finding suggests that dietary polar lipids improve human cognition through an enhancement of neuronal maturation and/or function.

Milk Fat Globule Membranes for Mental Health across the Human Lifespan

The milk fat globule membrane (MFGM) contains bioactive proteins, carbohydrates, and lipids. Polar lipids found in the MFGM play a critical role in maintaining cell membrane integrity and neuronal signalling capacity, thereby supporting brain health. This review summarises the literature on the MFGM and its phospholipid constituents for improvement of mental health across three key stages of the human lifespan, i.e., infancy, adulthood, and older age. MFGM supplementation may improve mental health by reducing neuroinflammation and supporting neurotransmitter synthesis through the gut-brain axis. Fortification of infant formula with MFGMs is designed to mimic the composition of breastmilk and optimise early gut and central nervous system development. Early behavioural and emotional development sets the stage for future mental health. In adults, promising results suggest that MFGMs can reduce the negative consequences of situational stress. Preclinical models of age-related cognitive decline suggest a role for the MFGM in supporting brain health in older age and reducing depressive symptoms. While there is preclinical and clinical evidence to support the use of MFGM supplementation for improved mental health, human studies with mental health as the primary target outcome are sparce. Further high-quality clinical trials examining the potential of the MFGM for psychological health improvement are important.

A systematic meta-review of systematic reviews on attention deficit hyperactivity disorder

BACKGROUND

There are now hundreds of systematic reviews on attention deficit hyperactivity disorder (ADHD) of variable quality. To help navigate this literature, we have reviewed systematic reviews on any topic on ADHD.

METHODS

We searched MEDLINE, PubMed, PsycINFO, Cochrane Library, and Web of Science and performed quality assessment according to the Joanna Briggs Institute Manual for Evidence Synthesis. A total of 231 systematic reviews and meta-analyses met the eligibility criteria.

RESULTS

The prevalence of ADHD was 7.2% for children and adolescents and 2.5% for adults, though with major uncertainty due to methodological variation in the existing literature. There is evidence for both biological and social risk factors for ADHD, but this evidence is mostly correlational rather than causal due to confounding and reverse causality. There is strong evidence for the efficacy of pharmacological treatment on symptom reduction in the short-term, particularly for stimulants. However, there is limited evidence for the efficacy of pharmacotherapy in mitigating adverse life trajectories such as educational attainment, employment, substance abuse, injuries, suicides, crime, and comorbid mental and somatic conditions. Pharmacotherapy is linked with side effects like disturbed sleep, reduced appetite, and increased blood pressure, but less is known about potential adverse effects after long-term use. Evidence of the efficacy of nonpharmacological treatments is mixed.

CONCLUSIONS

Despite hundreds of systematic reviews on ADHD, key questions are still unanswered. Evidence gaps remain as to a more accurate prevalence of ADHD, whether documented risk factors are causal, the efficacy of nonpharmacological treatments on any outcomes, and pharmacotherapy in mitigating the adverse outcomes associated with ADHD.

Phosphatidylserine, inflammation, and central nervous system diseases

Phosphatidylserine (PS) is an anionic phospholipid in the eukaryotic membrane and is abundant in the brain. Accumulated studies have revealed that PS is involved in the multiple functions of the brain, such as activation of membrane signaling pathways, neuroinflammation, neurotransmission, and synaptic refinement. Those functions of PS are related to central nervous system (CNS) diseases. In this review, we discuss the metabolism of PS, the anti-inflammation function of PS in the brain; the alterations of PS in different CNS diseases, and the possibility of PS to serve as a therapeutic agent for diseases. Clinical studies have showed that PS has no side effects and is well tolerated. Therefore, PS and PS liposome could be a promising supplementation for these neurodegenerative and neurodevelopmental diseases.