Relevance of TNF-α gene polymorphisms in nonalcoholic fatty liver disease

Cadmium Pollution Deteriorates the Muscle Quality of Labeo rohita by Altering Its Nutrients and Intestinal Microbiota Diversity

The detrimental effects of cadmium (Cd), a hazardous heavy metal, on fish have triggered global concerns. While the ecotoxicity of Cd on fish has been investigated, the impact of Cd on muscle quality and its correlation with the gut microbiota in fish remains scarce. To comprehensively uncover Cd effects based on preliminary muscle Cd deposition, relevant studies, and ecological Cd pollution data, we exposed Labeo rohita to Cd under concentrations of 0.00 (control), 0.05, and 0.40 mg/L for 30 days and assessed fish health, muscle quality, and intestinal bacterial diversity. We observed significant Cd bioaccumulation in the fish muscle and intestine at 0.40 mg/L treatment, adversely impacting fish health with lower growth indices, higher mortality, behavioral aberrations, and clinical anomalies. More interestingly, Cd exposure decreased muscle quality by reducing nutrient levels, including fat, protein, iron, zinc, mono and polyunsaturated fatty acids, and increasing free amino acids and saturated fatty acids. Elevated oxidative stress markers, including total superoxide dismutase (T-SOD), catalase (CAT), and hydrogen peroxide (H2O2), were detected in the muscles, indicating degraded quality as a result of damage to cellular structures including proteins, lipids, and DNA. Simultaneously, we found Cd exposure altered fish intestinal microbial diversity, impairing muscle nutrient assimilation, thereby influencing muscle quality. Functional predictions suggested a decrease in pathways related to fermentation and chemoheterotrophy in the exposed groups. Overall, this study highlights how Cd toxicity jeopardizes fish health and deteriorates muscle quality which needs to be addressed for human benefit.

Rice-shrimp culture: a better intestinal microbiota, immune enzymatic activities, and muscle relish of crayfish (Procambarus clarkii) in Sichuan Province

Intestinal microbiota play an important role in the intestinal immunity and nutrient absorption, even muscle nutritional components, and the composition and function were affected by environment. In this study, the intestinal microbiota and immune enzyme, nutritional flavor of muscle of crayfish in rice field, and pond cultivation model were compared in summer and autumn. The results of Shannon diversity and Chao 1 index of intestinal microbiota based on 16S sequencing analysis showed that the diversity and abundance in autumn were higher than in summer. And the diversity and abundance of intestinal microbiota of different model in the same season were different. Four dominant phyla (relative abundance > 5% at least in one sample) of the intestinal microbiota were Bacteroidetes, Firmicutes, Proteobacteria, and Tenericutes. From summer to autumn, the intestinal immune enzyme activity of crayfish in both models showed a decreasing trend. In summer, the activity of catalase and alkaline phosphatase of crayfish cultured in the pond was significantly higher than that in rice field (P < 0.05). In autumn, the activity of catalase and lysozyme of crayfish cultured in rice field was significantly higher than that in pond (P < 0.05). The contents of umami and sweetish amino acids of muscle were higher in rice field than in pond, and the percentage of glutamic acid and alanine was significantly higher in rice field than in pond (P < 0.05). Thus, rice field model can make crayfish a more stable intestinal environment and a better intestinal immune enzyme activity and muscular flavor. Key points • The intestinal microbiota of crayfish in rice field had tended to stabilize from summer to autumn. • The crayfish had better nutrient absorption and stronger immune abilities in the rice field. • The crayfish cultured in rice field had higher overall umami concentration than in pond.

Different susceptibility to insulin resistance and fatty liver depending on the combination of TNF-α C-857T and adiponectin G+276T gene polymorphisms in Japanese subjects with type 2 diabetes

The C-857T promoter polymorphism of TNF-α gene is associated with obese type 2 diabetes, while the adiponectin G+276T gene polymorphism in intron 2 may influence the fat accumulation in the liver. In this study, we examined effects of these polymorphisms on clinical markers of insulin resistance and fatty liver (a liver/spleen CT ratio < 0.9). These polymorphisms were determined in 342 Japanese subjects with type 2 diabetes. The liver/spleen CT ratio was lower in the subjects with the adiponectin +276G/G genotype than that in the subjects with the +276T allele (P < 0.05), indicating that fat accumulation in the liver is associated with the +276G/G genotype. Multiple comparisons among the 4 combinations of each polymorphism of the TNF-α and adiponectin genes revealed a significant difference in the liver/spleen CT ratio (P < 0.05) among the 4 groups, indicating that the gene combinations influence the degree of fat accumulation in the liver. The subjects carrying the TNF-α -857T allele (C/T or T/T genotype) and the adiponectin +276G/G genotype had greater risks for fatty liver and insulin resistance that was evaluated by higher levels of fasting insulin and homeostasis model assessment of insulin resistance, as compared with the other groups. Therefore, Japanese subjects with the TNF-α -857T allele and the adiponectin +276G/G genotype may be more susceptible to insulin resistance and fatty liver. The present study provides the evidence for the interaction between TNF-α and adiponectin genes in the insulin resistance and fatty liver in Japanese subjects with type 2 diabetes.

Role of mitochondria in nonalcoholic fatty liver disease--from origin to propagation

OBJECTIVES

Mitochondria play a major role in cell energy-generating processes and integrate several signalling pathways to control cellular life and death.

DESIGN AND METHODS

Several liver diseases are characterized by mitochondrial alterations which are directly or indirectly dependent on the activation of intracellular stress cascades or receptor-mediated pathways. This article examines the role of mitochondrial dysfunction in critical initiating or propagating events in fatty liver infiltration and nonalcoholic fatty liver disease (NAFLD). Genetic variants and the role of drug-induced toxicity have been considered.

RESULTS

Key alterations of mitochondrial physiology associated with hepatocyte fatty changes are described. The value of novel non-invasive diagnostic methods to detect mitochondrial metabolic alterations is also discussed.

CONCLUSIONS

Mitochondrial metabolic remodeling is a predominant factor in the appearance and perpetuation of hepatocyte fat accumulation. Non-invasive techniques to identify mitochondrial dysfunction and proper mitochondria protection are two necessary clinical steps for an efficient management of NAFLD.

Association of tumor necrosis factor-α gene promoter polymorphism at sites -308 and -238 with non-alcoholic fatty liver disease: a meta-analysis

BACKGROUND AND AIM

Environmental and genetic factors play a role in the pathogenesis and natural history of non-alcoholic fatty liver disease (NAFLD). The objective of this study was to quantitatively evaluate the association between tumor necrosis factor (TNF)-α gene promoter polymorphism at sites -308 and -238 and NAFLD susceptibility.

METHODS

We performed an extensive search of relevant studies and made a meta-analysis, including eight studies with 837 NAFLD cases and 990 controls in the association between TNF-α -308 polymorphism and NAFLD; and seven studies with 771 cases and 787 controls in TNF-α -238 polymorphism.

RESULTS

The combined results showed that there was a significant difference in TNF-α-238 genotype distribution between NAFLD and control based on all studies (GA/AA vs GG [odds ratio = 2.06, 95% confidence interval = 1.58-2.69, P < 0.000,01]). However, the combined results based on all studies showed there was no evidence of association of TNF-α-308 genotype distribution between NAFLD cases and controls (GA/AA vs GG [odds ratio = 1.08, 95% confidence interval = 0.82-1.42, P = 0.60]). When stratifying for race, the significant results did not change materially compared with whole populations.

CONCLUSION

This meta-analysis suggested that TNF-α gene promoter polymorphism at position -238 but not -308 might be a risk factor for NAFLD.