Concentration and composition of odd-chain fatty acids in phospholipids and triacylglycerols in Chinese human milk throughout lactation.

Human milk represents the gold standard for infant nutrition, with approximately 50% of the energy in human milk derived from lipids. Odd-chain fatty acids (OCFAs) have been recognized as a category of bioactive milk fatty acids in recent research; however, limited data exist on OCFAs in human milk. This study collected human milk samples spanning the postpartum period from 0 to 400 days. Phospholipids containing OCFAs (PL-OCFAs) were determined in 486 human milk samples using hydrophilic liquid chromatography-electrospray ionization-triquadrupole-mass spectrometry. Triacylglycerols containing OCFAs (TAG-OCFAs) were analyzed in 296 human milk samples using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. The average total concentration of PL-OCFA ranged from 30.89 ± 14.27 mg L-1 to 93.48 ± 36.55 mg L-1 during lactation, and the average total TAG-OCFA content ranged from 103.1 ± 147.15 mg L-1 to 965.41 ± 651.67 mg L-1. Despite the lower absolute concentration of PL-OCFA, its relative concentration (8.75%-11.75%) was significantly higher than that of TAG-OCFA (0.37%-1.85%) throughout lactation. PC-OCFA, SM-OCFA and PE-OCFA are major sub-classes of PL-OCFA. Furthermore, C17:0 was the major chain length in both PL-OCFA and TAG-OCFA, followed by C15:0. C17:1 was characteristic of TAG-OCFA, while long-chain fatty acids C19:0, C21:0 and C23:0 were characteristic of PL-OCFA. Our findings highlighted the importance of bioactive lipids in human milk, suggesting that OCFAs could be targeted in future studies in relation to the health and development of infants.

Trajectories of Human Milk Gangliosides during the First Four Hundred Days and Maternal-to-Offspring Transfer of Gangliosides: Results from a Chinese Cohort Study.

BACKGROUND: Gangliosides are crucial for early-life cognition and immunity development. However, limited data exist on gangliosides within the Chinese population, and maternal-to-fetal/infant ganglioside transport remains unclear. OBJECTIVES: This study aimed to investigate gangliosides concentrations and trajectories in Chinese human milk during the first 400 d of lactation, and seek to understand gangliosides transmission between mother and offspring. METHODS: This study involved 921 cross-sectional participants providing human milk samples across 0-400 d of lactation and 136 longitudinal participants offering maternal plasma, cord plasma, and human milk samples within the first 45 d postpartum. Ultrahigh-performance liquid chromatography-tandem mass spectrometry was used for the quantification of gangliosides. RESULTS: Human milk GM3 (Neu5Acα2-3Galß1-4GlcßCer) concentration increased from 2.29 ± 1.87 to 13.93 ± 4.82 µg/mL, whereas GD3 (Neu5Acα2-8Neu5Acα2-3Galß1-4GlcßCer) decreased from 17.94 ± 6.41 to 0.30 ± 0.50 µg/mL during the first 400 d postpartum (all P < 0.05). Consistent results were observed in cross-sectional and longitudinal participants. GD3 concentration gradually increased from maternal plasma (1.58 µg/mL) through cord plasma (2.05 µg/mL) to colostrum (21.35 µg/mL). Significant positive correlations were observed between maternal and cord plasma for both GM3 (r = 0.30, P < 0.001) and GD3 (r = 0.35, P < 0.001), and maternal plasma GD3 also correlated positively with colostrum concentrations (r = 0.21, P = 0.015). Additionally, in maternal and cord plasma, gangliosides were mainly linked with 16- and 18-carbon fatty acids. However, human milk GM3 showed a broad spectrum of fatty acid chain lengths, whereas GD3 was primarily tied to very long-chain fatty acids (≥20 carbon). CONCLUSIONS: We identified an increase in GM3 and a decrease in GD3 concentration in human milk, with GD3 notably more concentrated in cord plasma and colostrum. Importantly, ganglioside concentrations in maternal plasma positively correlated with those in cord plasma and colostrum. Our findings contribute to the existing Chinese data on gangliosides and enhance understanding of their transmission patterns from mother to offspring. This trial was registered at chictr.org.cn as ChiCTR1800015387.

Betaine alleviates cognitive impairment induced by homocysteine through attenuating NLRP3-mediated microglial pyroptosis in an m6A-YTHDF2-dependent manner.

Dementia, with homocysteine (Hcy) as an important risk factor, is a severe public health problem in the aging society. Betaine serves as a methyl donor and plays an important role in reducing Hcy. However, the effects and mechanisms of betaine on Hcy-induced cognitive impairment remain unclear. Firstly, SD rats were injected with Hcy (400 µg/kg) through vena caudalis, and betaine (2.5 % w/v) was supplemented via drinking water for 14 days. Betaine supplementation could attenuate Hcy-induced cognitive impairment in the Y maze and novel object recognition tests by repairing brain injury. Meanwhile, microglial activation was observed to be inhibited by betaine supplementation using immunofluorescence and sholl analysis. Secondly, HMC3 cells were treated with betaine, which was found to decrease the ROS level, ameliorate cell membrane rupture, reduce the release of LDH, IL-18 and IL-1ß, and attenuate the damage of microglia to neurons. Mechanistically, betaine alleviates cognitive impairment by inhibiting microglial pyroptosis via reducing the expressions of NLRP3, ASC, pro-caspase-1, cleaved-caspase-1, GSDMD, GSDMD-N, IL-18 and IL-1ß. Betaine treatment can increase SAM/SAH ratio, confirming its enhancement on methylation capacity. Furthermore, betaine treatment was found to enhance N6-methyladenosine (m6A) modification of NLRP3 mRNA, and reduced the NLRP3 mRNA stability through increasing the expression of the m6A reader YTH N6-methyladenosine RNA binding protein 2 (YTHDF2). Finally, silencing YTHDF2 could reverse the inhibitory effect of betaine on pyroptosis. Our data demonstrated that betaine attenuated Hcy-induced cognitive impairment by suppressing microglia pyroptosis via inhibiting the NLRP3/caspase-1/GSDMD pathway in an m6A-YTHDF2-dependent manner.

Longitudinal changes in choline concentration and associated factors in human breast milk.

BACKGROUND: Human breast milk is the primary source of choline and choline-containing compounds for infants at early stages of life. Choline data across lactation in Chinese human milk were limited. OBJECTIVE: This study aimed to quantify the five choline compounds in Chinese human breast milk and explore associated factors. METHODS: A total of 540 lactating mothers from the MUAI (Maternal Nutrition and Infant Investigation) study were included. The content of water-soluble choline (free choline, phosphocholine, glycerophosphocholine) and lipid-soluble choline (phosphatidylcholine, sphingomyelin) in 892 human milk samples collected from 0 to 400 days postpartum were examined, and associated factors were explored. RESULTS: Choline concentrations in human milk varied from postpartum day 0-400 (92.06 ± 65.22 to 171.01 ± 47.84 mg/L). Water-soluble choline was the major component (88.6%-93.8%) in human milk and ranged from 793.03 (659.22) to 1544.43 (443.32) µmol/L. Its trajectory followed that of total choline, increasing from colostrum to transitional milk and then declining in mature milk. In contrast, lipid-soluble choline accounted for 6.2%-11.4% over lactation and had an opposite trajectory. Choline composition varied by delivery mode and parity history. CONCLUSION: The concentrations of individual choline and choline-containing compounds during lactation in Chinese human breast milk were described for the first time. Our results address gaps in extant Chinese human milk choline data and support tailored dietary reference intakes for Chinese lactating women and infants. Our data describes the level and profile of choline from 0 to 400 days postpartum in Chinese human breast milk. This is the most updated data on choline and also the first report of water-soluble choline as the predominant type in Chinese human milk. Our results compensate for the deficiencies in data on choline in Chinese human milk. CLINICAL TRIAL REGISTRATION: Clinical Trial Registry number: ChiCTR1800015387. Web link to study on registry: https://www.chictr.org.cn/index.aspx.

Effects of low-dose B vitamins plus betaine supplementation on lowering homocysteine concentrations among Chinese adults with hyperhomocysteinemia: a randomized, double-blind, controlled preliminary clinical trial.

PURPOSE: To test the hypothesis that daily supplementation with low-dose B vitamins plus betaine could significantly reduce plasma homocysteine concentrations in Chinese adults with hyperhomocysteinemia and free from background mandatory folic acid fortification. METHODS: One hundred apparently healthy adults aged 18-65 years with hyperhomocysteinemia were recruited in South China from July 2019 to June 2021. They were randomly assigned to either the supplement group (daily supplementation: 400 µg folic acid, 8 mg vitamin B6, 6.4 µg vitamin B12 and 1 g betaine) or the placebo group for 12 weeks. Fasting venous blood was collected at baseline, week 4 and week 12 to determine the concentrations of homocysteine, folate, vitamin B12 and betaine. Generalized estimation equations were used for statistical analysis. RESULTS: Statistically significant increments in blood concentrations of folate, vitamin B12 and betaine after the intervention in the supplement group indicated good participant compliance. At baseline, there were no significant differences in plasma homocysteine concentration between the two groups (P = 0.265). After 12-week supplementation, compared with the placebo group, there was a significant reduction in plasma homocysteine concentrations in the supplement group (mean group difference - 3.87; covariate-adjusted P = 0.012; reduction rate 10.1%; covariate-adjusted P < 0.001). In the supplement group, the decreased concentration of plasma homocysteine was associated with increments of blood concentrations of both folate (ß = -1.680, P = 0.004) and betaine (ß = -1.421, P = 0.020) after 12 weeks of supplementation. CONCLUSIONS: Daily supplementation with low-dose B vitamins plus betaine for 12 weeks effectively decreased plasma homocysteine concentrations in Chinese adults with hyperhomocysteinemia. TRIAL REGISTRATION: This trial was registered at clinicaltrials.gov as NCT03720249 on October 25, 2018. Website: https://clinicaltrials.gov/ct2/show/NCT03720249 .

Profiling of triacylglycerol composition in the breast milk of Chinese mothers at different lactation stages.

Triacylglycerol (TAG) is the primary constituent of human milk fat and plays a vital role in the healthy development of infants. But few studies reported the sophisticated profile of TAG molecular species in human breast milk and its temporal changes during a prolonged lactation period. An efficient ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) method was adopted to examine TAGs. A total of 128 TAGs in 296 human breast milk samples collected during postnatal 0 to 400 days were identified. The changes in the human milk TAG profile mainly took place in the early stages of lactation (postnatal 0-45 days), and the TAG profile became stable in mature milk after 200 days of lactation. Odd chain fatty acids (OC-FAs) may be important markers for identifying human breast milk of different lactation stages. This study could provide evidence for developing safe and efficacious human-milk substitutes for children without access to human breast milk.

Lactational Changes of Phospholipids Content and Composition in Chinese Breast Milk.

Phospholipids are pivotal polar lipids in human milk and essential for infants' growth and development, especially in the brain and cognitive development. Its content and composition are affected by multiple factors and there exist discrepancies in different studies. In this study, we determined five major phospholipids classes (phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, phosphatidylcholine, and sphingomyelin) in 2270 human milk samples collected from 0 to 400 days postpartum in six regions of China. The high-performance liquid chromatography coupled with an evaporative light scattering detector (HPLC-ELSD) was performed to quantify the phospholipids. Total phospholipid median (IQR) content was in a range between 170.38 ± 96.52 mg/L to 195.69 ± 81.80 mg/L during lactation and was higher concentrated in colostrum milk and later stage of lactation (after 200 days postpartum) compared with that in the samples collected between 10 to 45 days postpartum. Variations in five major sub-class phospholipids content were also observed across lactation stages (phosphatidylethanolamine: 52.61 ± 29.05 to 59.95 ± 41.74 mg/L; phosphatidylinositol: 17.65 ± 10.68 to 20.38 ± 8.55 mg/L; phosphatidylserine: 15.98 ± 9.02 to 22.77 ± 11.17 mg/L; phosphatidylcholine: 34.13 ± 25.33 to 48.64 ± 19.73 mg/L; sphingomyelin: 41.35 ± 20.31 to 54.79 ± 35.26 mg/L). Phosphatidylethanolamine (29.18-32.52%), phosphatidylcholine (19.90-25.04%) and sphingomyelin (22.39-29.17%) were the dominant sub-class phospholipids in Chinese breast milk during the whole lactation period. These results updated phospholipids data in Chinese human milk and could provide evidence for better development of secure and effective human milk surrogates for infants without access to breast milk.

Profiling of phospholipid molecular species in human breast milk of Chinese mothers and comprehensive analysis of phospholipidomic characteristics at different lactation stages.

Phospholipids are critical for milk digestion and infant development. But the profile of phospholipid molecular species in human milk and its dynamic changes during the lactation period have never been reported. The present study elucidated precise qualitative and quantitative analysis of 258 phospholipid molecular species in 486 human milk samples. Phosphatidylcholine is the most abundant class, followed by phosphatidylserine, phosphatidylethanolamine and sphingomyelin as the second abundant class in different lactation period. The plasmalogens declined along the lactation period, and the polyunsaturated-phospholipids decreased after 10-15 days. The decrease of phosphatidylcholines and phosphatidylglycerols, and the increase of lysophosphatidylethanolamines and lysophosphatidylcholines are critical changes from 0 to 5 days to 10-15 days; increase of phosphatidylinositols, phosphatidylserines, lysophosphatidylethanolamines and lysophosphatidylcholines is the key changes from 10-15 days to 40-45 days; the decrease of most phospholipid molecular species is the characteristic change from 40-45 days to 200-240 days; and the phospholipid profile achieved stability after 200 days.