Metabolism of [U-(13)C]aspartate by astroglial cultures: nuclear magnetic resonance analysis of the culture media

1H-NMR-based metabolomic study of striatal injury in rats with copper-loaded Wilson's disease by Chinese and Western medicine intervention

OBJECTIVE

To investigate the metabolic mechanisms of Chinese and Western medicines on the metabolic network of striatal injury in a copper-loaded rat model of Wilson disease (WD) from a metabolomic perspective.

METHODS

We divided 60 rats into 4 groups of 15 rats each according to a random number table, namely the control group, the model group, the Bushen Huoxue Huazhuo Recipe group, and the penicillamine group, and subsequently replicated the WD copper-loaded rat model according to the literature method for a total of 12 weeks. From the 7th week onwards, each intervention group was given an equivalent dose of the corresponding drug, and the control and model groups were given an equal volume of saline gavage until the end of the model replication. We used ¹H NMR metabolomics techniques combined with multivariate statistical methods to describe the changes in the striatal metabolic profile of nerve injury in Wilson's disease and to analyze the effect of different treatments on their biomarker interventions.

RESULTS

Nerve cell damage was evident in the WD copper-loaded rat model and could be reduced to varying degrees by different methods of intervention in the striatal nerve cells. The content of glycine, serine metabolism, and valine metabolism decreased in WD copper-loaded rat model; aspartate content increased after penicillamine intervention; glycolytic metabolism, valine metabolism, taurine metabolism, and tyrosine metabolism increased in the group of Bushen Huoxue Huazhuo Recipe.

CONCLUSION

Different intervention methods of Chinese and Western medicine affect aspartate, glycolysis, taurine, tyrosine, valine, and carbon metabolism in striatal tissues of WD copper-loaded rats, and can regulate the metabolism of small molecules, which in turn have certain repairing effects on nerve damage in WD copper-loaded rats.

Chlorogenic Acid Ameliorates High-Fat and High-Fructose Diet-Induced Cognitive Impairment via Mediating the Microbiota-Gut-Brain Axis

Chlorogenic acid (CGA) displays cognition-improving properties, but the underlying mechanisms remain unclear. Herein, CGA supplementation (150 mg/kg body weight) for 14 weeks significantly prevented obesity and insulin resistance, cognitive-behavioral disturbances, and synaptic dysfunction induced by a high-fat and high-fructose diet (HFFD). Moreover, CGA supplementation enhanced the expression of genes enriched in the neuroactive ligand-receptor interaction pathway and reduced inflammatory factor expressions. Furthermore, CGA treatment increased gut microbiota diversity and the level of bacterial genera producing SCFAs. CGA also decreased the concentration of energy metabolism substrates, while it increased phosphorylcholine. Finally, we observed a significant correlation among synaptic transmission genes, gut microbiota, and neurotransmission in the CGA supplementation group by targeted multiomics analysis. Together, our results supported that the alteration of gut microbiota and metabolite composition is the underlying mechanism of CGA improving cognitive function. CGA is also a promising intervention strategy to prevent HFFD-induced cognitive impairment.

New perspectives on the roles of pyrimidines in the central nervous system

Since 1956, when exogenous uridine and cytidine were found to be necessary for the maintenance of perfused rat brain function, the co-existence of de novo synthesis, salvage pathways and removal of pyrimidine bases in the CNS has been a controversial subject. Here, we review studies on metabolites and enzymes of pyrimidine metabolism through more than 60 years. In view of known and newly-described inherited pyrimidine and purine disorders - some with complex clinical profiles of neurological impairments - we underline the necessity to investigate how the different pathways work together in the developing brain and then sustain plasticity, regeneration and neuro-transmission in the adult CNS. Experimentally, early incorporation studies in animal brain slices and homogenates with radio-labelled nucleosides or precursors demonstrated salvage activity or de novo synthesis. Later, the nucleoside transporters and organic anionic transporters underlying uptake of metabolites and anti-pyrimidine drugs in the CNS were identified. Recently, the expression of de novo enzymes in glial cells and neurons was verified using (immuno) histochemical and in-situ-hybridization techniques. Adult brain was shown to take up or produce all pyrimidine (deoxy) ribonucleosides or, after uptake and phosphorolysis of nucleosides, to make use of ribose for different purposes, including energy. More recently, non-canonical pyrimidine bases (5mC, 5hmC) have been found most notably in brain, pointing to considerable postreplicative DNA metabolism, with the need for pyrimidine-specific enzymes. Even more perspectives are emerging, with advances in genome analysis and in the manipulation of expression from the gene.

Correlation chemical shift imaging with low-power adiabatic pulses and constant-density spiral trajectories

In this work we introduce the concept of correlation chemical shift imaging (CCSI). Novel CCSI pulse sequences are demonstrated on clinical scanners for two-dimensional Correlation Spectroscopy (COSY) and Total Correlation Spectroscopy (TOCSY) imaging experiments. To date there has been limited progress reported towards a feasible and robust multivoxel 2D COSY. Localized 2D TOCSY imaging is shown for the first time in this work. Excitation with adiabatic GOIA-W(16,4) pulses (Gradient Offset Independent Adiabaticity Wurst modulation) provides minimal chemical shift displacement error, reduced lipid contamination from subcutaneous fat, uniform optimal flip angles, and efficient mixing for coupled spins, while enabling short repetition times due to low power requirements. Constant-density spiral readout trajectories are used to acquire simultaneously two spatial dimensions and f(2) frequency dimension in (k(x),k(y),t(2)) space in order to speed up data collection, while f(1) frequency dimension is encoded by consecutive time increments of t(1) in (k(x),k(y),t(1),t(2)) space. The efficient spiral sampling of the k-space enables the acquisition of a single-slice 2D COSY dataset with an 8 × 8 matrix in 8:32  min on 3 T clinical scanners, which makes it feasible for in vivo studies on human subjects. Here we present the first results obtained on phantoms, human volunteers and patients with brain tumors. The patient data obtained by us represent the first clinical demonstration of a feasible and robust multivoxel 2D COSY. Compared to the 2D J-resolved method, 2D COSY and TOCSY provide increased spectral dispersion which scales up with increasing main magnetic field strength and may have improved ability to unambiguously identify overlapping metabolites. It is expected that the new developments presented in this work will facilitate in vivo application of 2D chemical shift correlation MRS in basic science and clinical studies.