Dietary Complex and Slow Digestive Carbohydrates Prevent Fat Deposits During Catch-Up Growth in Rats

Comprehensive analysis of lncRNA and mRNA expression in triploid rainbow trout (Oncorhynchus mykiss) liver in response to chronic hypoxia

Long non-coding RNAs (lncRNAs) play a crucial role in response to environmental stresses (e.g. hypoxia) in triploid rainbow trout. However, the action mechanism of lncRNAs in triploid rainbow trout liver in chronic hypoxia is still not fully understood. Therefore, we investigated the mechanism of lncRNA and its target genes in response to chronic hypoxia in triploid rainbow trout using high-throughput RNA sequencing and bioinformatics analysis in this study. Results showed that 37 differentially expressed lncRNAs (DElncRNAs) and 780 differentially expressed mRNAs (DEmRNAs) were found in hypoxic group compared to normoxic group. Target genes of DElncRNAs were mainly enriched in Ferroptosis, One carbon pool by folate, Gluconeogenesis and Retinol metabolism pathways. GSEA enrichment of DEmRNA showed significant enrichment for retinol metabolism and steroid hormone biosynthesis. There were 9 key proteins in above pathways forming a protein-protein interaction (PPI) network. As a result of co-expression of DElncRNAs with DEmRNAs, 9 key DEmRNAs and 13 DElncRNAs were screened. Based on the Pearson correlation coefficient > 0.99 and the co-expression relationship between DElncRNAs and DEmRNAs, 3 pairs (MSTRG.5664.2-pck1, XR_002475125.2-pck1, and XR_005052355.1-pck1) of key target gene pairs were screened. Finally, qRT-PCR verified the expression of critical genes. These results provide basic data for rainbow trout to cope with chronic hypoxia and technical support for the development of rainbow trout feeds adapted to hypoxic environments.

High glucose-induced alternative splicing of MEF2D in macrophages promotes vascular chronic inflammation in type 2 diabetes mellitus by mediating M1 macrophage polarization

OBJECTIVES

To investigate the effects of a high-glucose environment in type 2 diabetes mellitus (T2DM) on Myocyte enhancer factor 2d (MEF2D) selective splicing and its impact on the disease process and mechanism.

METHODS

Human monocyte (THP-1) cells were induced into macrophages with phorbol 12-myristate 13-acetate (PMA), and treated with high glucose for 24 h. PCR confirmed MEF2D splicing products. MEF2D or MEF2D-AS overexpression vectors were transfected into macrophages, and ELISA detected inflammatory factors; flow cytometry analyzed MI/M2 phenotypes; and levels of LC3, PI3K, and LAMP2 were measured. Autophagic flux detection; co-immunoprecipitation detected MEF2D and KCNMA1 interaction; WB and RT-qPCR assessed KCNMA1 expression. Macrophages co-cultured with endothelial cells were analyzed by ELISA for vascular inflammation factors MMP-9, Cys-C, and hsCRP.

RESULTS

High glucose-induced alternative splicing of MEF2D at 86-132 aa. MEF2D-AS group showed higher inflammatory factors, increased M1 phenotype, lower autophagy gene expression, and higher vascular inflammation factors compared to MEF2D group. Autophagy activator Rapamycin or KCNMA1 overexpression reversed these effects. MEF2D targeted KCNMA1, and MEF2D-AS overexpression led to decreased KCNMA1, increased inflammatory factors, M1 polarization, autophagy inhibition, and higher vascular inflammation factors.

CONCLUSION

High glucose induces MEF2D alternative splicing in macrophages, inhibiting autophagy and promoting M1 polarization via KCNMA1 down-regulation, thus promoting chronic inflammation in T2DM vessels.

Moderating carbohydrate digestion rate in mice promotes fat oxidation and metabolic flexibility revealed through a new approach to assess metabolic substrate utilization

PURPOSE

Superior metabolic flexibility, or the ability to efficiently switch between oxidation of carbohydrate and fat, is inversely associated with obesity and type 2 diabetes. The influence of dietary factors on metabolic flexibility is incompletely understood. This study examined the impact of dietary carbohydrate digestion rate on metabolic flexibility and metabolic substrate utilization.

METHODS

We employed percent relative cumulative frequency (PRCF) analyses coupled with a new application of modeling using the Mixed Weibull Cumulative Distribution function to examine respiratory exchange ratio (RER) data from adult wild-type mice and mice lacking the mucosal maltase-glucoamylase enzyme (Mgam) under different dietary carbohydrate conditions, with diets matched for total carbohydrate contents and containing different ratios of slowly digestible starch (SDS) and resistant starch (RS), or that were high in sucrose or fat. Fungal amyloglucosidase (AMG) was administered in drinking water to increase carbohydrate digestion rate. We devised a Metabolic Flexibility Factor (MFF) to quantitate metabolic flexibility for each dietary condition and mouse genotype, with higher MFF indicating higher metabolic flexibility.

RESULTS

Diets high in SDS exhibited lower average RER and higher metabolic flexibility (MFF) than diets high in resistant starch, sucrose, or fat. Diets containing high and intermediate amounts of SDS led to a more complete shift to fat oxidation. While mouse genotype had minimal effects on substrate oxidation and MFF, AMG supplementation shifted substrate utilization to carbohydrate oxidation and generally decreased MFF.

CONCLUSIONS

Consumption of slowly digestible carbohydrates improved measures of metabolic substrate utilization at the whole-body level in adult mice.

Preparation, Structural Characterisation, and Bioactivities of Fructans: A Review

Polysaccharides are important components of higher plants and have attracted increasing attention due to their many nutraceutical benefits in humans. Fructans, heterogeneous fructose polymers that serve as storage carbohydrates in various plants, represent one of the most important types of natural polysaccharides. Fructans have various physiological and therapeutic effects, which are beneficial to health, and have the ability to prevent or treat various diseases, allowing their wide use in the food, nutraceutical, and pharmaceutical industries. This article reviews the occurrence, metabolism, preparation, characterisation, analysis, and bioactivity of fructans. Further, their molecular weight, monosaccharide composition, linkages, and structural determination are described. Taken together, this review provides a theoretical foundation for further research into the structure-function relationships of fructans, as well as valuable new information and directions for further research and application of fructans in functional foods.

Intake of slow-digesting carbohydrates is related to changes in the microbiome and its functional pathways in growing rats with obesity induced by diet

INTRODUCTION

The main cause of insulin resistance in childhood is obesity, which contributes to future comorbidities as in adults. Although high-calorie diets and lack of exercise contribute to metabolic disease development, food quality rather than the quantity of macronutrients is more important than food density. The purpose of the present study was to examine the effects of changing the quality of carbohydrates from rapidly to slowly digestible carbohydrates on the composition of the gut microbiota and the profiles of the functional pathways in growing rats with obesity due to a high-fat diet (HFD).

METHODS

During the course of 4 weeks, rats growing on an HFD-containing carbohydrates with different digestive rates were fed either HFD-containing carbohydrates with a rapid digestion rate (OBE group) or HFD-containing carbohydrates with a slow digestion rate (OBE-ISR group). A non-obese group (NOB) was included as a reference, and rats were fed on a rodent standard diet (AIN93G). An analysis of gut microbiota was conducted using 16S rRNA-based metagenomics; a linear mixed-effects model (LMM) was used to determine changes in abundance between baseline and 4 weeks of treatment, and functional pathways were identified. Gut microbiota composition at bacterial diversity and relative abundance, at phylum and genus levels, and functional profiles were analyzed by integrating the Integrated Microbial Genomes (IMG) database.

RESULTS

The groups showed comparable gut microbiota at baseline. At the end of the treatment, animals from the ISR group exhibited differences at the phylum levels by decreasing the diversity of Fisher's index and Firmicutes (newly named as Bacillota), and increasing the Pielou's evenness and Bacteroidetes (newly named as Bacteroidota); at the genus level by increasing Alistipes, Bifidobacterium, Bacteroides, Butyricimonas, Lachnoclostridium, Flavonifractor, Ruminiclostridium 5, and Faecalibaculum and decreasing Muribaculum, Blautia, and Ruminiclostridium 9. Remarkably, relative abundances of genera Tyzzerella and Angelakisella were higher in the OBE group compared to NOB and OBE-ISR groups. In addition, some microbiota carbohydrate metabolism pathways such as glycolysis, glucuronic acid degradation, pentose phosphate pathway, methanogenesis, and fatty acid biosynthesis exhibited increased activity in the OBE-ISR group after the treatment. Higher levels of acetate and propionate were found in the feces of the ISR group compared with the NOB and OBE groups.

CONCLUSION

The results of this study demonstrate that replacing rapidly digestible carbohydrates with slowly digestible carbohydrates within an HFD improve the composition of the gut microbiota. Consequently, metabolic disturbances associated with obesity may be prevented.

Dietary Complex and Slow Digestive Carbohydrates Promote Bone Mass and Improve Bone Microarchitecture during Catch-Up Growth in Rats

Catch-up growth is a process that promotes weight and height gains to recover normal growth patterns after a transient period of growth inhibition. Accelerated infant growth is associated with reduced bone mass and quality characterized by poor bone mineral density (BMD), content (BMC), and impaired microarchitecture. The present study evaluated the effects of a diet containing slow (SDC) or rapid (RDC) digestible carbohydrates on bone quality parameters during the catch-up growth period in a model of diet-induced stunted rats. The food restriction period negatively impacted BMD, BMC, and microarchitecture of appendicular and axial bones. The SDC diet was shown to improve BMD and BMC of appendicular and axial bones after a four-week refeeding period in comparison with the RDC diet. In the same line, the micro-CT analysis revealed that the trabecular microarchitecture of tibiae and vertebrae was positively impacted by the dietary intervention with SDC compared to RDC. Furthermore, features of the cortical microstructure of vertebra bones were also improved in the SDC group animals. Similarly, animals allocated to the SDC diet displayed modest improvements in growth plate thickness, surface, and volume compared to the RDC group. Diets containing the described SDC blend might contribute to an adequate bone formation during catch-up growth thus increasing peak bone mass, which could be linked to reduced fracture risk later in life in individuals undergoing transient undernutrition during early life.

Impact of slow versus rapid digesting carbohydrates on substrate oxidation in pre-pubertal children: A randomized crossover trial

BACKGROUND & AIMS

Consumption of rapid digesting sugars by children are under increased scrutiny because of their contribution to unhealthy weight gain. Previous studies in adults and children have suggested that altering the blend of carbohydrates (CHOs) consumed may cause shifts in substrate utilization. The purpose of this study was to examine the effects of consuming a slow digesting carbohydrate (SDC) and rapid digesting carbohydrate (RDC) on CHO and fat oxidation, glucose, and insulin responses at rest, during exercise, and post-exercise rest in pre-pubescent children.

METHODS

A randomized, double-blind, crossover design was used. Nineteen pre-pubescent children (n = 10 boys, n = 9 girls, mean ± standard error, age = 9.84 ± 0.37-yrs) participated. Visits to the laboratory began with a 30-min measurement of resting metabolism followed by consumption of either an RDC or SDC drink. Postprandial resting metabolism was recorded for 60-min, immediately followed by 60-min of submaximal cycling exercise while metabolism was recorded, which was immediately followed by another 60-min recording of post-exercise metabolism. Total CHO and fat oxidation, endogenous and exogenous CHO oxidation, blood glucose, and insulin were assessed.

RESULTS

Total CHO oxidation rate (g∙min-1) was greater after the RDC drink at 60 min (p = 0.032). Endogenous CHO oxidation rate (g∙min-1) was greater after the SDC drink at 15 min (p ≤ 0.010). Cumulative endogenous CHO oxidation (g) was greater after the SDC drink at 45 min (p = 0.009). Endogenous CHO oxidation accounted for a greater proportion of substrate oxidation after the first 60-min rest period (p = 0.028), while exogenous CHO oxidation accounted for a greater proportion of substrate oxidation for the RDC at all time points (p ≤ 0.019).

CONCLUSIONS

The present study provides novel data suggesting that an SDC promotes greater endogenous substrate utilization in pre-pubertal children, which may have beneficial health impacts on energy intake and carbohydrate regulation/metabolism during growth and development.

CLINICAL TRIALS REGISTRY NUMBER

NCT03185884, clinicaltrials.gov.