Metabolic profiling of plasma amino acids shows that histidine increases following the consumption of pork

Mediterranean Diet Combined with Regular Aerobic Exercise and Hemp Protein Supplementation Modulates Plasma Circulating Amino Acids and Improves the Health Status of Overweight Individuals

Plant protein is considered a sustainable health-promoting strategy to prevent metabolic syndrome. Lifestyle changes (including dietary patterns and exercise) have been demonstrated to exert an effect on human health by modulating the biochemical status in humans. The objective of this study was to assess whether supplementation with hemp protein within a Mediterranean diet context together with exercise could help to ameliorate the metabolic statuses of patients prone to developing metabolic syndrome. For this study, 23 patients followed with Mediterranean diet and engaged in aerobic exercise according to the WHO's recommendations, while also being supplemented with hemp protein, for 12 weeks. A comparison of anthropometric, biochemical, and mineral data as well as amino acid values was made between the start and the end of the study, with the subjects acting as their own control group. Statistical analyses included a paired t-test, Wilcoxon paired test, Pearson correlation coefficient, and Sparse Partial Least Squares Discriminant Analysis to evaluate significant differences and correlations among parameters. There were statistically significant changes in total cholesterol, HDL-C (+52.3%), LDL-C (-54.0%), and TAG levels (-49.8%), but not in glucose plasma levels. Following the intervention, plasma concentrations of some amino acids, including α-aminoadipic acid, phosphoethanolamine, and 1-metylhistidine, increased, whereas those of asparagine and alanine declined. Different correlations between amino acids and the other parameters evaluated were reported and discussed. A Mediterranean diet combined with regular aerobic exercise, together with protein supplementation, can highly improve the metabolic parameters and anthropometric parameters of subjects with obesity and impaired glucose levels, ameliorating their health status and likely delaying the development of metabolic syndrome.

Longitudinal characterization of the metabolome of dairy cows transitioning from one lactation to the next: Investigations in blood serum

The objective of this study was to characterize changes in the serum metabolome and various indicators of oxidative balance in dairy cows starting 2 wk before dry-off and continuing until wk 16 of lactation. Twelve Holstein dairy cows (body weight 745 ± 71 kg, body condition score 3.43 ± 0.66; mean ± SD) were housed in a tiestall barn from 10 wk before to 16 wk after parturition. Cows were dried off 6 wk before the expected calving date (mean dry period length = 42 d). From 8 wk before calving to 16 wk after calving, blood samples were taken weekly to study redox metabolism by determining antioxidant capacity, measured as the ferric-reducing ability of plasma, reactive oxidative metabolites, oxidative stress index, oxidative damage of lipids, measured as thiobarbituric acid reactive substances, and glutathione peroxidase activity. According to these results, dairy cows had the lowest serum antioxidant capacity and greater levels of oxidative stress during the dry-off period and the early postpartum period. For metabolomics, a subset of serum samples including wk -7 (before dry-off), -5 (after dry-off), -1, 1, 5, 10, and 15 relative to calving were used. A targeted metabolomics approach was performed using liquid chromatography and flow injection with electrospray ionization triple quadrupole mass spectrometry using the MxP Quant 500 kit (Biocrates Life Sciences AG). A total of 240 metabolites in serum were used in the final data analysis. Principal component analysis revealed a clear separation by days of sampling, indicating a remarkable shift in metabolic phenotype between the dry period and late and early lactation. Changes in many non-lipid metabolites associated with one-carbon metabolism, the tricarboxylic acid cycle, the urea cycle, and AA catabolism were observed in the study, with changes in AA serum concentrations likely related to factors such as energy and nitrogen balance, digestive efficiency, and changing diets. The study confirmed an extensive remodeling of the serum lipidome in peripartum dairy cows, highlighting the importance of changes in acylcarnitine (acylCN), phosphatidylcholines (PC), and triacylglycerols (TG), as they play a crucial role in lipid metabolism. Results showed that short-chain acylCN increased after dry-off and decreased thereafter, whereas lipid-derived acylCN increased around parturition, suggesting that more fatty acids could enter mitochondria. Phospholipids and sphingolipids in serum showed changes during lactation. In particular, concentrations of sphingomyelins, PC, and lysoPC decreased around calving but increased in mid- and late lactation. In contrast, concentrations of TG remained consistently low after parturition. The serum concentrations of bile acids fluctuated during the dry period and lactation, with glycocholic acid, cholic acid, glycodeoxycholic acid, and taurocholic acid showing the greatest concentrations. These changes are likely due to the interplay of diet, liver function, and the ability of the gut microbiota to convert primary to secondary bile acids. Overall, these descriptive results may aid in hypothesis generation and in the design and interpretation of future metabolite-based studies in dairy cows. Furthermore, they contribute to our understanding of the physiological ranges in serum metabolites relative to the lactation cycle of the dairy cow.

A Newly Developed Indicator of Overeating Saturated Fat Based on Serum Fatty Acids and Amino Acids and Its Association With Incidence of Type 2 Diabetes: Evidence From Two Randomized Controlled Feeding Trials and a Prospective Study

Objective

Hyper-caloric intake of saturated fatty acids (SFAs) is common in modern societies, probably contributing to the epidemic of type 2 diabetes mellitus (T2DM). This study conducted two randomized controlled trials (RCTs) for developing a new indicator that can assess the nutritional status and examined its association with incidence of T2DM.

Methods

In RCT 1, healthy participants were randomly assigned into three groups, namely, control group (n = 40), overfeeding group 1 (100 g butter per day, n = 37), and overfeeding group 2 (120 g butter per day, n = 37). In RCT 2, healthy subjects were randomly assigned into two groups, namely, control group (n = 52) and high-fat group (300-extra kcal/day from diet that was designed by high-fat diet, n = 58). In the prospective cohort, 4,057 participants aged 20–74 years were enrolled and followed up over 5.3 years. Serum profiles of fatty acids and amino acids were measured.

Results

In RCT 1, serum fatty acids, including C14:0 and C18:0, increased, whereas C18:2, C20:4, C22:5, and C22:6 decreased; serum amino acids, including tyrosine, alanine, and aminobutyric acid, increased, whereas histidine and glycine decreased (p < 0.05). Among these serum fatty acids and amino acids, changes in C14:0, C20:4, tyrosine, histidine, and glycine were also observed in RCT 2. An indicator was developed based on the five fatty acids and amino acids, namely, C14:0 × tyrosine × 1,000/[C20:4 × (glycine + histidine)], and it significantly identified participants in the intervention group with area under the curve (AUC) (95% CI) being 0.85 (0.77–0.92). The indicator was significantly associated with incidence of T2DM in the prospective cohort with HRs (95% CIs) from bottom quartile to top quartile being 1,1.21 (0.82–1.77), 1.60 (1.12–2.30), 2.04 (1.42–2.94).

Conclusion

The newly developed indicator in RCTs can be used in assessing the nutritional status of hypercaloric intake of SFA and predicting the development of T2DM.

Mammalian target of rapamycin signaling and ubiquitin-proteasome-related gene expression in skeletal muscle of dairy cows with high or normal body condition score around calving

The objective of the current study was to investigate the effects of overconditioning around calving on gene expression of key components of the mammalian target of rapamycin (mTOR) pathway and ubiquitin-proteasome system (UPS) in skeletal muscle as well as the AA profiles in both serum and muscle of periparturient cows. Fifteen weeks antepartum, 38 multiparous Holstein cows were allocated to either a high body condition group (HBCS; n = 19) or a normal body condition group (NBCS; n = 19) and were fed different diets until dry-off (d -49 relative to calving) to amplify the difference. The groups were also stratified for comparable milk yields (NBCS: 10,361 ± 302 kg; HBCS: 10,315 ± 437 kg). At dry-off, the NBCS cows (parity: 2.42 ± 1.84; body weight: 665 ± 64 kg) had a body condition score (BCS) <3.5 and backfat thickness (BFT) <1.2 cm, whereas the HBCS cows (parity: 3.37 ± 1.67; body weight: 720 ± 57 kg) had a BCS >3.75 and BFT >1.4 cm. During the dry period and the subsequent lactation, both groups were fed identical diets but maintained the BCS and BFT differences. Blood samples and skeletal muscle biopsies (semitendinosus) were repeatedly (d -49, +3, +21, and +84 relative to calving) collected for assessing the concentrations of free AA and the mRNA abundance of various components of mTOR and UPS. The differences in BCS and BFT were maintained throughout the study. The circulating concentrations of most AA with the exception of Gly, Gln, Met, and Phe increased in early lactation in both groups. The serum concentrations of Ala (d +21 and +84) and Orn (d +84) were lower in HBCS cows than in NBCS cows, but those of Gly, His, Leu, Val, Lys, Met, and Orn on d -49 and Ile on d +21 were greater in HBCS cows than in NBCS cows. The serum concentrations of 3-methylhistidine, creatinine, and 3-methylhistidine:creatinine ratio increased after calving (d +3) but did not differ between the groups. The muscle concentrations of all AA (except for Cys) remained unchanged over time and did not differ between groups. The muscle concentrations of Cys were greater on d -49 but tended to be lower on d +21 in HBCS cows than in NBCS cows. On d +21, mTOR and eukaryotic translation initiation factor 4E binding protein 1 mRNA abundance was greater in HBCS cows than in NBCS cows, whereas ribosomal protein S6 kinase 1 was not different between the groups. The mRNA abundance of ubiquitin-activating enzyme 1 (d +21), ubiquitin-conjugating enzyme 1 (d +21), atrogin-1 (d +21), and ring finger protein-1 (d +3) enzymes was greater in HBCS cows than in NBCS cows, whereas ubiquitin-conjugating enzyme 2 was not different between the groups. The increased mRNA abundance of key components of mTOR signaling and of muscle-specific ligases of HBCS cows may indicate a simultaneous activation of anabolic and catabolic processes and thus increased muscle protein turnover, likely as a part of the adaptive response to prevent excessive loss of skeletal muscle mass during early lactation.

The interaction of zinc and the blood-brain barrier under physiological and ischemic conditions

Zinc is the second most abundant metal in human and serves as an essential trace element in the body. During the past decades, zinc has been found to play important roles in central nervous system, such as the development of neurons and synaptic activities. An imbalance of zinc is associated with brain diseases. The blood-brain barrier (BBB) maintains the homeostasis of the microenvironment, regulating the balance of zinc in the brain. A compromised BBB is the main cause of severe complications in cerebral ischemic patients, such as hemorrhage transformation, inflammation and edema. Recent studies reported that zinc in the brain may be a potential target for integrative protection against ischemic brain injury. Although zinc has long been regarded as important transmitters in central nervous system, the critical role of zinc dyshomeostasis in damage to the BBB has not been fully recognized. In this review, we summarize the role of the BBB in regulating homeostasis of zinc in physiological conditions and the effects of changes in zinc levels on the permeability of the BBB in cerebral ischemia. The integrity of BBB maintains the homeostasis of zinc in pathological conditions, while the balance of zinc in the brain and the circulation maintains the normal function of the BBB. Interrupting the zinc/BBB system will disturb the microenvironment in the brain, leading to pathological diseases. In stroke patients, zinc may serve as a potential target for protecting the BBB and reducing hemorrhage transformation, inflammation and edema.