Absorption Kinetics of Ethanolamine Plasmalogen and Its Hydrolysate in Mice

Lymphatic absorption characteristics of eicosapentaenoic acid -enriched phosphoethanolamine plasmalogen and its gastric and intestinal hydrolysates

The aim of this work was to study the lymphatic absorption characteristics of gastric hydrolysates and intestinal hydrolysates of eicosapentaenoic acid-enriched phosphoethanolamine plasmalogen (EPA-pPE) with focusing on the fate of EPA and vinyl ether bonds in the lymph fluid using lymphatic intubation and lipidomics. The results showed that the EPA peak occurred earlier in the gastric (1.5 h) and intestinal (1 h) hydrolysates than in the EPA-pPE group (3 h) with EPA peak content being 2.03 and 1.46 times higher, suggesting pre-hydrolysis contributed to lymphatic absorption. Further, duodenal injection of gastric hydrolysates sn2 EPA-lysoPE produced higher levels of EPA-LPC, PC, PE, and PG. Meanwhile, intestinal hydrolysates free EPA and sn1 lyso-pPE enriched the sn1 + 2 + 3 TG (20:5_20:5_20:5) and increased the vinyl ether bond-containing lipids, such as PE (18:0p_18:0) and PE (18:0p_20:4). This study provides insight into dietary molecular structures of EPA and plasmalogen.

Marine Plasmalogens: A Gift from the Sea with Benefits for Age-Associated Diseases

Aging increases oxidative and inflammatory stress caused by a reduction in metabolism and clearance, thus leading to the development of age-associated diseases. The quality of our daily diet and exercise is important for the prevention of these diseases. Marine resources contain various valuable nutrients, and unique glycerophospholipid plasmalogens are found abundantly in some marine invertebrates, including ascidians. One of the major classes, the ethanolamine class (PlsEtn), exists in a high ratio to phospholipids in the brain and blood, while decreased levels have been reported in patients with age-associated diseases, including Alzheimer's disease. Animal studies have shown that the administration of marine PlsEtn prepared from marine invertebrates improved PlsEtn levels in the body and alleviated inflammation. Animal and human studies have reported that marine PlsEtn ameliorates cognitive impairment. In this review, we highlight the biological significance, relationships with age-associated diseases, food functions, and healthcare materials of plasmalogens based on recent knowledge and discuss the contribution of marine plasmalogens to health maintenance in aging.

Plasmalogens Eliminate Aging-Associated Synaptic Defects and Microglia-Mediated Neuroinflammation in Mice

Neurodegeneration is a pathological condition in which nervous system or neuron losses its structure, function, or both leading to progressive neural degeneration. Growing evidence strongly suggests that reduction of plasmalogens (Pls), one of the key brain lipids, might be associated with multiple neurodegenerative diseases, including Alzheimer’s disease (AD). Plasmalogens are abundant members of ether-phospholipids. Approximately 1 in 5 phospholipids are plasmalogens in human tissue where they are particularly enriched in brain, heart and immune cells. In this study, we employed a scheme of 2-months Pls intragastric administration to aged female C57BL/6J mice, starting at the age of 16 months old. Noticeably, the aged Pls-fed mice exhibited a better cognitive performance, thicker and glossier body hair in appearance than that of aged control mice. The transmission electron microscopic (TEM) data showed that 2-months Pls supplementations surprisingly alleviate age-associated hippocampal synaptic loss and also promote synaptogenesis and synaptic vesicles formation in aged murine brain. Further RNA-sequencing, immunoblotting and immunofluorescence analyses confirmed that plasmalogens remarkably enhanced both the synaptic plasticity and neurogenesis in aged murine hippocampus. In addition, we have demonstrated that Pls treatment inhibited the age-related microglia activation and attenuated the neuroinflammation in the murine brain. These findings suggest for the first time that Pls administration might be a potential intervention strategy for halting neurodegeneration and promoting neuroregeneration.

Enrichment of n-3 containing ether phospholipids in plasma after 30 days of krill oil compared with fish oil supplementation

There are conflicting findings over the bioavailability of long-chain n-3 polyunsaturated fatty acids (n-3 PUFA) from krill oil (KO) compared with fish oil (FO) in short- and long-term studies. The aim of this study was to compare the effects of KO versus FO on the enrichment of molecular species of plasma phospholipids in young women following a 30-day consumption of the n-3 oils. Eleven healthy women aged 18-45 years consumed seven capsules of KO per day (containing a total of 1.27 g n-3 PUFA) or five capsules of FO per day (total of 1.44 g n-3 PUFA) for 30 days in a randomized crossover study, separated by at least a 30-day washout period. Fasting blood samples were collected at day zero (baseline), day 15 and day 30 and analyzed by HPLC-MS/MS for molecular species of phospholipids. Supplementation increased n-3 PUFA in main phospholipids classes in both groups. After 30 days of supplementation, 35 out of 70 molecular species containing eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPAn-3) had a significantly greater concentration in KO group compared with the FO treated group. The majority (89%) of the differentiated molecular species were choline and ethanolamine ether-phospholipids. These data reveal that analysis of plasma phospholipids following 30 days of consumption of KO (a marine oil rich in phospholipids, including ether phospholipids) resulted in an enrichment of n-3 PUFA in molecular species of ether-phospholipids compared with FO (a triacylglycerol-rich marine oil).

Dietary Sphingolipids Contribute to Health via Intestinal Maintenance

As sphingolipids are constituents of the cell and vacuole membranes of eukaryotic cells, they are a critical component acquired from our daily diets. In the present review, we highlight the knowledge regarding how dietary sphingolipids affect our health, particularly our intestinal health. Animal- and plant-derived foods contain, respectively, sphingomyelin (SM) and glucosylceramide (GlcCer) as their representative sphingolipids, and the sphingoid base as a specific structure of sphingolipids also differs depending upon the source and class. For example, sphingosine is predominant among animal sphingolipids, and tri-hydroxy bases are present in free ceramide (Cer) from plants and fungi. Dietary sphingolipids exhibit low absorption ratios; however, they possess various functions. GlcCer facilitates improvements in intestinal impairments, lipid metabolisms, and skin disorders, and SM can exert both similar and different effects compared to those elicited by GlcCer. We discuss the digestion, absorption, metabolism, and function of sphingolipids while focused on the structure. Additionally, we also review old and new classes in the context of current advancements in analytical instruments.

Ethanolamine Plasmalogen Suppresses Apoptosis in Human Intestinal Tract Cells in Vitro by Attenuating Induced Inflammatory Stress

Ethanolamine plasmalogen (PlsEtn) is a subtype of ethanolamine glycerophospholipids (EtnGpl). Recently, PlsEtn has attracted increasing research interest due to its beneficial effects in health and disease; however, its functional role in colonic health has not been well established. This study was conducted to determine the mechanism underlying the antiapoptotic effect of PlsEtn in human intestinal tract cells under induced inflammatory stress. Lipopolysaccharide induced apoptosis of differentiated Caco-2 cells, which was suppressed by EtnGpl in a dose-dependent manner. Cells treated with ascidian muscle EtnGpl containing high levels of PlsEtn demonstrated a lower degree of apoptosis, and downregulated TNF-α and apoptosis-related proteins compared to those treated with porcine liver EtnGpl containing low PlsEtn. This indicates that PlsEtn exerted the observed effects, which provided protection against induced inflammatory stress. Overall, our results suggest that PlsEtn with abundant vinyl ether linkages is potentially beneficial in preventing the initiation of inflammatory bowel disease and colon cancer.