Low-grade chronic inflammation induces behavioral stereotypy in rats

The role of cytokines as predictors for NAFLD-related diseases: A bidirectional Mendelian randomization study

BACKGROUND

Prior research has highlighted associations between inflammatory cytokines and non-alcoholic fatty liver disease (NAFLD), but causal relationships remain unclear. Employing the Mendelian randomization (MR) approach, this investigation aims to explore the connection between 41 inflammatory cytokines and NAFLD-related diseases.

METHODS

Our research implemented bidirectional study focusing on 41 cytokines in 8,293 Finns, predicting genetic associations with NAFLD, nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. We primarily utilized the inverse variance weighted (IVW) method to evaluate the bidirectional relationships. Additionally, a sensitivity analysis was carried out to ensure the reliability of our findings.

RESULTS

An elevated risk for NAFLD was correlated with both IL-2 (OR = 1.226, 95 % CI = 1.018-1.477, p = 0.031) and TNF-β (OR = 1.151, 95 % CI = 1.011-1.310, p = 0.033). IL-16 is associated with decreased NAFLD risk (OR = 0.820, 95 % CI = 0.719-0.934, p = 0.033). β-NGF (OR = 2.495, 95 % CI = 1.019-6.108, p = 0.045) and SCGFβ (OR = 1.541, 95 % CI = 1.052-2.256, p = 0.026) are linked to higher NASH risk. No significant associations were found for fibrosis and cirrhosis. Furthermore, the causal relationship between genetic predisposition to NAFLD-related diseases and various inflammatory cytokines was established.

CONCLUSIONS

Our MR analysis identifies specific cytokines as genetic predictors for NAFLD and NASH. IL-2 and TNF-β increase NAFLD risk, IL-16 appears protective, and β-NGF and SCGFβ are associated with greater NASH risk. These insights are crucial for understanding the etiology and treatment of NAFLD-related diseases.

Non-alcoholic Fatty Liver Disease: Also a Disease of the Brain? A Systematic Review of the Preclinical Evidence

Non-alcoholic fatty liver disease (NAFLD) currently affects 25% of the global adult population. Cognitive impairment is a recently recognised comorbidity impeding memory, attention, and concentration, affecting the patients' activities of daily living and reducing their quality of life. This systematic review provides an overview of the evidence for, and potential pathophysiological mechanisms behind brain dysfunction at a neurobiological level, in preclinical NAFLD. We performed a systematic literature search for animal models of NAFLD studying intracerebral conditions using PubMed, Embase and Scopus. We included studies that reported data on neurobiology in rodent and pig models with evidence of steatosis or steatohepatitis assessed by liver histology. 534 unique studies were identified, and 30 studies met the selection criteria, and were included. Findings of neurobiological changes were divided into five key areas: (1) neuroinflammation, (2) neurodegeneration, (3) neurotransmitter alterations, (4) oxidative stress, and (5) changes in proteins and synaptic density. Despite significant heterogeneity in the study designs, all but one study of preclinical NAFLD reported changes in one or more of the above key areas when compared to control animals. In conclusion, this systematic review supports an association between all stages of NAFLD (from simple steatosis to non-alcoholic steatohepatitis (NASH)) and neurobiological changes in preclinical models.

Effects of a Functional Food Made with Salvia hispanica L. (Chia Seed), Amaranthus hypochondriacus L. (Amaranth), and an Ethanolic Extract of Curcuma longa L. (Curcumin) in a Rat Model of Childhood Obesity

Obesity is a global health problem and is increasing in prevalence in most countries. Although obesity affects all age groups, children are the most vulnerable sector. Functional foods are novel formulated foods containing substances (i.e., nutrients, phytochemicals, probiotics, etc.) that have potential health-enhancing or disease-preventing value. The research objective was to study the possible beneficial effects of providing a functional food made with amaranth flour, chia seed, and curcumin extract on the metabolism and behavior of a rat model of childhood obesity. Male Wistar rat pups from two litters of different sizes, a normal litter (NL) (10 pups) and a small litter (SL) (4 pups), were used. After weaning, the rats were fed a hypercaloric diet (HD) or an HD supplemented with the functional food mixture. Body weight and energy intake were measured for seven weeks, and locomotor activity, learning, and memory tests were also performed. At the end of the experiment, glucose and lipid metabolism parameters were determined. The results showed that in this model of obesity produced by early overfeeding and the consumption of a hypercaloric diet, anxiety-like behaviors and metabolic alterations occurred in the rat offspring; however, the provision of the functional food failed to reduce or prevent these alterations, and an exacerbation was even observed in some metabolic indicators. Interestingly, in the NL rats, the provision of the functional food produced some of the expected improvements in health, such as significant decreases in body weight gain and liver cholesterol and non-significant decreases in adipose tissue and leptin and insulin serum levels.

Cognitive Functions, Neurotransmitter Alterations, and Hippocampal Microstructural Changes in Mice Caused by Feeding on Western Diet

Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD) is the most common chronic liver disease in Western countries. It is becoming increasingly evident that peripheral organ-centered inflammatory diseases, including liver diseases, are linked with brain dysfunctions. Therefore, this study aims to unravel the effect of MASLD on brain histology, cognitive functions, and neurotransmitters. For this purpose, mice fed for 48 weeks on standard (SD) or Western diet (WD) were evaluated by behavioral tests, followed by sacrifice and analysis of the liver-brain axis including histopathology, immunohistochemistry, and biochemical analyses. Histological analysis of the liver showed features of Metabolic Dysfunction-Associated Steatohepatitis (MASH) in the WD-fed mice including lipid droplet accumulation, inflammation, and fibrosis. This was accompanied by an elevation of transaminase and alkaline phosphatase activities, increase in inflammatory cytokine and bile acid concentrations, as well as altered amino acid concentrations in the blood. Interestingly, compromised blood capillary morphology coupled with astrogliosis and microgliosis were observed in brain hippocampus of the WD mice, indicating neuroinflammation or a disrupted neurovascular unit. Moreover, attention was impaired in WD-fed mice along with the observations of impaired motor activity and balance, enhanced anxiety, and stereotyped head-twitch response (HTR) behaviors. Analysis of neurotransmitters and modulators including dopamine, serotonin, GABA, glutamate, and acetylcholine showed region-specific dysregulation in the brain of the WD-fed mice. In conclusion, the induction of MASH in mice is accompanied by the alteration of cellular morphology and neurotransmitter expression in the brain, associated with compromised cognitive functions.

Non-alcoholic fatty liver disease (NAFLD) and mental illness: Mechanisms linking mood, metabolism and medicines

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the world and one of the leading indications for liver transplantation. It is one of the many manifestations of insulin resistance and metabolic syndrome as well as an independent risk factor for cardiovascular disease. There is growing evidence linking the incidence of NAFLD with psychiatric illnesses such as schizophrenia, bipolar disorder and depression mechanistically via genetic, metabolic, inflammatory and environmental factors including smoking and psychiatric medications. Indeed, patients prescribed antipsychotic medications, regardless of diagnosis, have higher incidence of NAFLD than population norms. The mechanistic pharmacology of antipsychotic-associated NAFLD is beginning to emerge. In this review, we aim to discuss the pathophysiology of NAFLD including its risk factors, insulin resistance and systemic inflammation as well as its intersection with psychiatric illnesses.

The live biotherapeutic Blautia stercoris MRx0006 attenuates social deficits, repetitive behaviour, and anxiety-like behaviour in a mouse model relevant to autism

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterised by deficits in social behaviour, increased repetitive behaviour, anxiety and gastrointestinal symptoms. The aetiology of ASD is complex and involves an interplay of genetic and environmental factors. Emerging pre-clinical and clinical studies have documented a potential role for the gut microbiome in ASD, and consequently, the microbiota represents a potential target in the development of novel therapeutics for this neurodevelopmental disorder. In this study, we investigate the efficacy of the live biotherapeutic strain, Blautia stercoris MRx0006, in attenuating some of the behavioural deficits in the autism-relevant, genetic mouse model, BTBR T+ Itpr3tf/J (BTBR). We demonstrate that daily oral administration with MRx0006 attenuates social deficits while also decreasing repetitive and anxiety-like behaviour. MRx0006 administration increases the gene expression of oxytocin and its receptor in hypothalamic cells in vitro and increases the expression of hypothalamic arginine vasopressin and oxytocin mRNA in BTBR mice. Additionally at the microbiome level, we observed that MRx0006 administration decreases the abundance of Alistipes putredinis, and modulates the faecal microbial metabolite profile. This alteration in the metabolite profile possibly underlies the observed increase in expression of oxytocin, arginine vasopressin and its receptors, and the consequent improvements in behavioural outcomes. Taken together, these findings suggest that the live biotherapeutic MRx0006 may represent a viable and efficacious treatment option for the management of physiological and behavioural deficits associated with ASD.

Bioinformatics study of the potential therapeutic effects of ginsenoside Rf in reversing nonalcoholic fatty liver disease

OBJECTIVE

Ginsenoside Rf, a tetracyclic triterpenoid only present in Panax ginseng, has been proven to relieve lipid metabolism and inflammatory reactions, which can be a potential treatment for nonalcoholic fatty liver disease (NAFLD). Therefore, this study aimed to reveal the underlying mechanisms of ginsenoside Rf in the treatment of early-stage NAFLD (NAFL) by using a bioinformatics method and biological experiments.

METHODS

Target genes associated with NAFL were screened from the Gene Expression Omnibus (GEO) database, a database repository of high-throughput gene expression data and hybridization arrays, chips, and microarrays. Subsequently, gene set enrichment analysis was performed by using Gene Ontology enrichment analysis tool. Then, the binding capacity between ginsenoside Rf and NAFL-related targets was evaluated by molecular docking. Finally, the FFA-induced HepG2 cell model treated with ginsenoside Rf was adopted to verify the effect of ginsenoside Rf and the related mechanisms.

RESULTS

There were 41 common differentially expressed genes in the GEO dataset. Gene Ontology and Reactome pathway enrichment analysis of the differentially expressed genes showed that many pathways could be related to the pathogenesis of NAFL, including those participating in the cytokine-mediated signaling pathway, G protein-coupled receptor signaling pathway, and response to lipopolysaccharide. Finally, the qRT-PCR analysis results indicated that ginsenoside Rf therapy could ameliorate the transcription of ANXA2, BAZ1A, DNMT3L and MMP9.

CONCLUSION

Our research discovered the relevant mechanisms and basic pharmacological effects of ginsenoside Rf in the treatment of NAFL. These results might facilitate the development of ginsenoside Rf as an alternative medication for NAFL.

Effect of Advanced Glycation End-Products and Excessive Calorie Intake on Diet-Induced Chronic Low-Grade Inflammation Biomarkers in Murine Models

Chronic Low-Grade Inflammation (CLGI) is a non-overt inflammatory state characterized by a continuous activation of inflammation mediators associated with metabolic diseases. It has been linked to the overconsumption of Advanced Glycation End-Products (AGEs), and/or macronutrients which lead to an increase in local and systemic pro-inflammatory biomarkers in humans and animal models. This review provides a summary of research into biomarkers of diet-induced CLGI in murine models, with a focus on AGEs and obesogenic diets, and presents the physiological effects described in the literature. Diet-induced CLGI is associated with metabolic endotoxemia, and/or gut microbiota remodeling in rodents. The mechanisms identified so far are centered on pro-inflammatory axes such as the interaction between AGEs and their main receptor AGEs (RAGE) or increased levels of lipopolysaccharide. The use of murine models has helped to elucidate the local and systemic expression of CLGI mediators. These models have enabled significant advances in identification of diet-induced CLGI biomarkers and resultant physiological effects. Some limitations on the translational (murine → humans) use of biomarkers may arise, but murine models have greatly facilitated the testing of specific dietary components. However, there remains a lack of information at the whole-organism level of organization, as well as a lack of consensus on the best biomarker for use in CLGI studies and recommendations as to future research conclude this review.

Atorvastatin has therapeutic potential for the fatty liver-induced memory dysfunction in rats, likely via its antioxidant and anti-inflammatory properties

This study aimed to evaluate the memory function in a rat model of fatty liver and to investigate the effects of statins on fatty liver, neuronal inflammation, oxidative stress and memory. In this study, 24 male rats were used and were divided into four groups consisting of 6 animals in each. Of them, 12 rats received liquid diet containing 35% fructose for 8 weeks in order to induce hepatosteatosis, while other animals had a normal nutrition. Group 1 served as controls and had a normal nutrition with no drug treatment. The animals in Group 2 had a normal nutrition and treated with atorvastatin. Group 3 received high-fructose diet with no drug treatment and Group 4 received high-fructose diet followed by atorvastatin treatment. After the two weeks of treatment period, passive avoidance tasks evaluating the memory were performed in both the study and control groups. The liver and brain were then removed for histologic, pathologic, and biochemical evaluation. In the non-treated rats with hepatosteatosis (Group 3), the lowest mean latency time and the highest mean histopathologic liver score, and brain TNF- α and MDA (Measurement of lipid peroxidation) were found (p < 0.00001). On the other hand, in the animals treated with atorvastatin, all these parameters were significantly higher than that of controls and significantly lower than that of Group 3 (p < 0.05). Fatty liver can increase inflammation and cause memory disorders, and atorvastatin may have a positive effect on cognitive disorders.

Similarities and interactions between the ageing process and high chronic intake of added sugars

In our societies, the proportions of elderly people and of obese individuals are increasing. Both factors are associated with high health-related costs. During obesity, many authors suggest that it is a high chronic intake of added sugars (HCIAS) that triggers the shift towards pathology. However, the majority of studies were performed in young subjects and only a few were interested in the interaction with the ageing process. Our purpose was to discuss the metabolic effects of HCIAS, compare with the effects of ageing, and evaluate how deleterious the combined action of HCIAS and ageing could be. This effect of HCIAS seems mediated by fructose, targeting the liver first, which may lead to all subsequent metabolic alterations. The first basic alterations induced by fructose are increased oxidative stress, protein glycation, inflammation, dyslipidaemia and insulin resistance. These alterations are also present during the ageing process, and are closely related to each other, one leading to the other. These basic alterations are also involved in more complex syndromes, which are also favoured by HCIAS, and present during ageing. These include non-alcoholic fatty liver disease, hypertension, neurodegenerative diseases, sarcopenia and osteoporosis. Cumulative effects of ageing and HCIAS have been seldom tested and may not always be strictly additive. Data also suggest that some of the metabolic alterations that are more prevalent during ageing could be related more with nutritional habits than to intrinsic ageing. In conclusion, it is clear that HCIAS interacts with the ageing process, accelerates the accumulation of metabolic alterations, and that it should be avoided.