Dietary fat composition shapes bile acid metabolism and severity of liver injury in a pig model of pediatric NAFLD.

The objective of this study was to investigate the effect of dietary fatty acid (FA) composition on bile acid (BA) metabolism in a pig model of NAFLD, by using a multiomics approach combined with histology and serum biochemistry. Thirty 20-day-old Iberian pigs pair-housed in pens were randomly assigned to receive 1 of 3 hypercaloric diets for 10 wk: 1) lard-enriched (LAR; n = 5 pens), 2) olive oil-enriched (OLI; n = 5), and 3) coconut oil-enriched (COC; n = 5). Animals were euthanized on week 10 after blood sampling, and liver, colon, and distal ileum (DI) were collected for histology, metabolomics, and transcriptomics. Data were analyzed by multivariate and univariate statistics. Compared with OLI and LAR, COC increased primary and secondary BAs in liver, plasma, and colon. In addition, both COC and OLI reduced circulating fibroblast growth factor 19, increased hepatic necrosis, composite lesion score, and liver enzymes in serum, and upregulated genes involved in hepatocyte proliferation and DNA repair. The severity of liver disease in COC and OLI pigs was associated with increased levels of phosphatidylcholines, medium-chain triacylglycerides, trimethylamine-N-oxide, and long-chain acylcarnitines in the liver, and the expression of profibrotic markers in DI, but not with changes in the composition or size of BA pool. In conclusion, our results indicate a role of dietary FAs in the regulation of BA metabolism and progression of NAFLD. Interventions that aim to modify the composition of dietary FAs, rather than to regulate BA metabolism or signaling, may be more effective in the treatment of NAFLD.NEW & NOTEWORTHY Bile acid homeostasis and signaling is disrupted in NAFLD and may play a central role in the development of the disease. However, there are no studies addressing the impact of diet on bile acid metabolism in patients with NAFLD. In juvenile Iberian pigs, we show that fatty acid composition in high-fat high-fructose diets affects BA levels in liver, plasma, and colon but these changes were not associated with the severity of the disease.

Postprandial Dried Blood Spot-Based Nutritional Metabolomic Analysis Discriminates a High-Fat, High-Protein Meat-Based Diet from a High Carbohydrate Vegan Diet: A Randomized Controlled Crossover Trial.

BACKGROUND: Due to the challenges associated with accurate monitoring of dietary intake in humans, nutritional metabolomics (including food intake biomarkers) analysis as a complementary tool to traditional dietary assessment methods has been explored. Food intake biomarker assessment using postprandial dried blood spot (DBS) collection can be a convenient and accurate means of monitoring dietary intake vs 24-hour urine collection. OBJECTIVE: The objective of this study was to use nutritional metabolomics analysis to differentiate a high-fat, high-protein meat (HFPM) diet from a high-carbohydrate vegan (HCV) diet in postprandial DBS and 24-hour urine. DESIGN: This was a randomized controlled crossover feeding trial. PARTICIPANTS/SETTING: Participants were healthy young adult volunteers (n = 8) in California. The study was completed in August 2019. INTERVENTION: The standardized isocaloric diet interventions included an HFPM and an HCV diet. Participants attended 2 intervention days, separated by a 2-week washout. MAIN OUTCOME MEASURES: During each intervention day, a finger-prick blood sample was collected in the fasting state, 3 hours post breakfast, and 3 hours post lunch. Participants also collected their urine for 24 hours. DBS and urine samples were analyzed by ultra-performance liquid chromatography mass spectrometry to identify potential food intake biomarkers. STATISTICAL ANALYSES PERFORMED: Principal component analysis for discriminatory analysis and univariate analysis using paired t tests were performed. RESULTS: Principal component analysis found no discrimination of baseline DBS samples. In both the postprandial DBS and 24-hour urine, post-HFPM consumption had higher (P < 0.05) levels of acylcarnitines, creatine, and cis-trans hydroxyproline, and the HCV diet was associated with elevated sorbitol (P < 0.05). The HFPM diet had higher concentrations of triacylglycerols with fewer than 54 total carbons in DBS, and 24-hour urine had higher nucleoside mono- and di-phosphates (P < 0.05). CONCLUSIONS: Nutritional metabolomics profiles of postprandial DBS and 24-hour urine collections were capable of differentiating the HFPM and HCV diets. The potential use of postprandial DBS-based metabolomic analysis deserves further investigation for dietary intake monitoring.

Activation of Energy Metabolism through Growth Media Reformulation Enables a 24-Hour Workflow for Cell-Free Expression.

Cell-free protein synthesis (CFPS) platforms have undergone numerous workflow improvements to enable diverse applications in research, biomanufacturing, and education. The Escherichia coli cell extract-based platform has been broadly adopted due to its affordability and versatility. The upstream processing of cells to generate crude cell lysate remains time-intensive and technically nuanced, representing one of the largest sources of cost associated with the biotechnology. To overcome these limitations, we have improved the processes by developing a long-lasting autoinduction media formulation for CFPS that obviates human intervention between inoculation and harvest. The cell-free autoinduction (CFAI) media supports the production of robust cell extracts from high cell density cultures nearing the stationary phase of growth. As a result, the total mass of cells and the resulting extract volume obtained increases by 400% while maintaining robust reaction yields of reporter protein, sfGFP (>1 mg/mL). Notably, the CFAI workflow allows users to go from cells on a streak plate to completing CFPS reactions within 24 h. The CFAI workflow uniquely enabled us to elucidate the metabolic limits in CFPS associated with cells grown to stationary phase in the traditional 2× YTPG media. Metabolomics analysis demonstrates that CFAI-based extracts overcome these limits due to improved energy metabolism and redox balance. The advances reported here shed new light on the metabolism associated with highly active CFPS reactions and inform future efforts to tune the metabolism in CFPS systems. Additionally, we anticipate that the improvements in the time and cost-efficiency of CFPS will increase the simplicity and reproducibility, reducing the barriers for new researchers interested in implementing CFPS.