Search Results (10)

The hepatic crown-like structure (hCLS) is a shell-like aggregate of macrophages surrounding a large lipid-laden dying hepatocyte. This feature was initially assumed to simply be a response to increased inflammatory stress during steatotic liver disease, but recent studies have shown that the hCLS is a critical site for lipid processing, inflammation regulation, fibrosis modulation and macrophage development. Furthermore, advances in lineage tracing and transcriptomic analysis have provided information on the nature of the macrophage subtypes present in the hCLS. The hCLS consists of a heterogeneous mixture of macrophages that arise largely from bone marrow-derived infiltrating macrophages (IMs) but also have some of the properties of Kupffer cells (KCs). Most of the cells are variations of Lipid-Associated Macrophages (LAMs) expressing surface proteins such as GPNMB, TREM2, CD9, CD36, CD63 and CD11c. In addition, a class of LAM-like KCs is also present and these typically express many of the LAM proteins along with KC lineage proteins such as VSIG4 and CLEC4F. The hCLS plays an important role in lipid disposition and inflammation but conflicting evidence appears to support roles in fibrogenesis, extracellular matrix remodeling, and matrix degradation. This review aims to describe the critical findings and discoveries made regarding hCLSs and their role in macrophage development and function in steatotic liver diseases. Full article

Background: MASLD is a disorder linked to lipid metabolism and obesity, increasingly prevalent among sedentary people and leading to hepatic fibrosis. Cyclodipeptides (CDPs) have promising anti-obesogenic and liver-protective potential. Methods: CDP treatment was evaluated in a chronic MASLD model using female Wistar rats fed an obesogenic diet, with assessments of insulin resistance, glucose tolerance, liver damage, oxidative stress, and the expression of genes related to metabolic function. Results: MASLD CDP-treated rats showed low visceral adipose tissue (VAT) content, improved insulin responsiveness and glucose tolerance, reduced steatosis, and reversed oxidant stress and the NRF2, GPX1, and GCLC expression. Furthermore, MASLD-related dysregulation of genes involved in lipid metabolism was restored, including vLDL transport (MTTP, APOB, and RASAL2), β-oxidation (PPAR-α, ACOX1, and FOXO1), lipogenesis (ACC1 and SREBP 1C), and fatty acid transport (PSD3 and CD36). In accordance, genes of key signaling pathways were also restored, including mTOR, TSC1, and TSC2, along with fibrosis and inflammation TGF-β, Fas, NF-κB, and IL-6. In VAT of MASLD animals, crown-like structures and adiposity density were diminished by CDP treatment, with increased expression of genes associated with beige-like adipose tissue remodeling, including PGC-1α, UCP1, NRF1, ATP6v1, CEBP-α, COX4i1, PPARγ, and CS. Consistently, the UCP1 and PGC-1α protein expression was increased in the VAT of MASLD animals treated with CDPs. Conclusions: The anti-MASLD effects of CDPs were associated with reversal of key pathogenic markers in the liver and VAT, suggesting remodeling of white adipose tissue (WAT) toward a beige-like adipose tissue phenotype. The findings suggest that CDPs may modulate adipose tissue structure and adipogenesis, underscoring their therapeutic relevance for MASLD. Full article

Background/Objectives: A high-fat diet (HFD) promotes hepatic steatosis, inflammation, and systemic metabolic imbalance. Notably, HFDs can affect the gut–liver axis and adipose tissue homeostasis. Galectin-3 (Gal-3) binds to β-galactosides and plays regulatory roles in the gut–liver axis, connecting metabolic stress with inflammation and tissue remodelling. The objective of this study was to investigate whether Gal-3 affects the gut–liver axis and adipose tissue biology after HFD supplementation. Methods: Six-week-old C57BL/6 mice were randomly divided into either wild-type (Lgals3^+/+) or knockout (Lgals3^−/−) groups. Both groups received an HFD orally for 12 weeks, along with their respective control groups. Physiological measurements and microscopic examination of the gut, liver, and fat tissue were conducted using optical microscopy. Results: The HFD induced obesity in Lgals3^+/+ mice, but not in Lgals3^−/− mice, which exhibited lower weight gain, food intake, daily energy intake, and energy efficiency than Lgals3^+/+ mice. Moreover, Lgals3^−/− HFD mice had hyperglycaemia and hyperinsulinemia. Histological analysis revealed hypertrophied adipose tissue in Lgals3^+/+ HFD mice with abundant Gal-3⁺ crown-like structures, rarely observed in Lgals3^−/− HFD mice. In the jejunum, Lgals3^+/+ HFD mice showed a significant reduction in Gal-3 expression in intestinal epithelial cells, whereas inflammatory signals were increased in Lgals3^−/− HFD mice. In the liver, Lgals3^+/+ HFD mice showed significant steatosis and macrophages expressing Gal-3. In contrast, Lgals3^−/− HFD mice showed pronounced hepatocyte ballooning, suggesting a more progressive stage of metabolic dysfunction-associated steatotic liver disease (MASLD). Conclusions: Together, these data suggest that Gal-3 protects the gut–liver axis and adipose tissue against cytotoxic effects caused by HFD. Full article

The potential roles of the gut microbiota in the pathogenesis of non-alcoholic fatty liver disease, including non-alcoholic steatohepatitis (NASH), have attracted increased interest. We have investigated the links between gut microbiota and NASH development in Tsumura-Suzuki non-obese mice fed a high-fat/cholesterol/cholate-based (iHFC) diet that exhibit advanced liver fibrosis using antibiotic treatments. The administration of vancomycin, which targets Gram-positive organisms, exacerbated the progression of liver damage, steatohepatitis, and fibrosis in iHFC-fed mice, but not in mice fed a normal diet. F4/80⁺-recruited macrophages were more abundant in the liver of vancomycin-treated iHFC-fed mice. The infiltration of CD11c⁺-recruited macrophages into the liver, forming hepatic crown-like structures, was enhanced by vancomycin treatment. The co-localization of this macrophage subset with collagen was greatly augmented in the liver of vancomycin-treated iHFC-fed mice. These changes were rarely seen with the administration of metronidazole, which targets anaerobic organisms, in iHFC-fed mice. Finally, the vancomycin treatment dramatically modulated the level and composition of bile acid in iHFC-fed mice. Thus, our data demonstrate that changes in inflammation and fibrosis in the liver by the iHFC diet can be modified by antibiotic-induced changes in gut microbiota and shed light on their roles in the pathogenesis of advanced liver fibrosis. Full article

Macrophages play critical roles in the pathogenesis of non-alcoholic steatohepatitis (NASH). However, it is unclear which macrophage subsets are critically involved in the development of inflammation and fibrosis in NASH. In TSNO mice fed a high-fat/cholesterol/cholate-based diet, which exhibit advanced liver fibrosis that mimics human NASH, we found that Kupffer cells (KCs) were less abundant and recruited macrophages were more abundant, forming hepatic crown-like structures (hCLS) in the liver. The recruited macrophages comprised two subsets: CD11c⁺/Ly6C⁻ and CD11c⁻/Ly6C⁺ cells. CD11c⁺ cells were present in a mesh-like pattern around the lipid droplets, constituting the hCLS. In addition, CD11c⁺ cells colocalized with collagen fibers, suggesting that this subset of recruited macrophages might promote advanced liver fibrosis. In contrast, Ly6C⁺ cells were present in doughnut-like inflammatory lesions, with a lipid droplet in the center. Finally, RNA sequence analysis indicates that CD11c⁺/Ly6C⁻ cells promote liver fibrosis and hepatic stellate cell (HSC) activation, whereas CD11c⁻/Ly6C⁺ cells are a macrophage subset that play an anti-inflammatory role and promote tissue repair in NASH. Taken together, our data revealed changes in liver macrophage subsets during the development of NASH and shed light on the roles of the recruited macrophages in the pathogenesis of advanced fibrosis in NASH. Full article

Obesity-related dysmetabolic conditions are amongst the most common causes of death globally. Indicaxanthin, a bioavailable betalain pigment from Opuntia ficus-indica fruit, has been demonstrated to modulate redox-dependent signalling pathways, exerting significant anti-oxidative and anti-inflammatory effects in vitro and in vivo. In light of the strict interconnections between inflammation, oxidative stress and insulin resistance (IR), a nutritionally relevant dose of indicaxanthin has been evaluated in a high-fat diet (HFD) model of obesity-related IR. To this end, biochemical and histological analysis, oxidative stress and inflammation evaluations in liver and adipose tissue were carried out. Our results showed that indicaxanthin treatment significantly reduced body weight, daily food intake and visceral fat mass. Moreover, indicaxanthin administration induced remarkable, beneficial effects on HFD-induced glucose dysmetabolism, reducing fasting glycaemia and insulinaemia, improving glucose and insulin tolerance and restoring the HOMA index to physiological values. These effects were associated with a reduction in hepatic and adipose tissue oxidative stress and inflammation. A decrease in RONS, malondialdehyde and NO levels, in TNF-α, CCL-2 and F4-80 gene expression, in p65, p-JNK, COX-2 and i-NOS protein levels, in crown-like structures and hepatic inflammatory foci was, indeed, observed. The current findings encourage further clinical studies to confirm the effectiveness of indicaxanthin to prevent and treat obesity-related dysmetabolic conditions. Full article

The development of obesity is characterized by the metabolic overload of tissues and subsequent organ inflammation. The health effects of krill oil (KrO) on obesity-associated inflammation remain largely elusive, because long-term treatments with KrO have not been performed to date. Therefore, we examined the putative health effects of 28 weeks of 3% (w/w) KrO supplementation to an obesogenic diet (HFD) with fat derived mostly from lard. The HFD with KrO was compared to an HFD control group to evaluate the effects on fatty acid composition and associated inflammation in epididymal white adipose tissue (eWAT) and the liver during obesity development. KrO treatment increased the concentrations of EPA and DHA and associated oxylipins, including 18-HEPE, RvE₂ and 14-HDHA in eWAT and the liver. Simultaneously, KrO decreased arachidonic acid concentrations and arachidonic-acid-derived oxylipins (e.g., HETEs, PGD₂, PGE₂, PGF₂α, TXB₂). In eWAT, KrO activated regulators of adipogenesis (e.g., PPARγ, CEBPα, KLF15, STAT5A), induced a shift towards smaller adipocytes and increased the total adipocyte numbers indicative for hyperplasia. KrO reduced crown-like structures in eWAT, and suppressed HFD-stimulated inflammatory pathways including TNFα and CCL2/MCP-1 signaling. The observed eWAT changes were accompanied by reduced plasma leptin and increased plasma adiponectin levels over time, and improved insulin resistance (HOMA-IR). In the liver, KrO suppressed inflammatory signaling pathways, including those controlled by IL-1β and M-CSF, without affecting liver histology. Furthermore, KrO deactivated hepatic REL-A/p65-NF-κB signaling, consistent with increased PPARα protein expression and a trend towards an increase in IkBα. In conclusion, long-term KrO treatment increased several anti-inflammatory PUFAs and oxylipins in WAT and the liver. These changes were accompanied by beneficial effects on general metabolism and inflammatory tone at the tissue level. The stimulation of adipogenesis by KrO allows for safe fat storage and may, together with more direct PPAR-mediated anti-inflammatory mechanisms, attenuate inflammation. Full article

We have shown that prebiotic xylo-oligosaccharides (XOS) increased beneficial gut microbiota (GM) and prevented high fat diet-induced hepatic steatosis, but the mechanisms associated with these effects are not clear. We studied whether XOS affects adipose tissue inflammation and insulin signaling, and whether the GM and fecal metabolome explain associated patterns. XOS was supplemented or not with high (HFD) or low (LFD) fat diet for 12 weeks in male Wistar rats (n = 10/group). Previously analyzed GM and fecal metabolites were biclustered to reduce data dimensionality and identify interpretable groups of co-occurring genera and metabolites. Based on our findings, biclustering provides a useful algorithmic method for capturing such joint signatures. On the HFD, XOS-supplemented rats showed lower number of adipose tissue crown-like structures, increased phosphorylation of AKT in liver and adipose tissue as well as lower expression of hepatic miRNAs. XOS-supplemented rats had more fecal glycine and less hypoxanthine, isovalerate, branched chain amino acids and aromatic amino acids. Several bacterial genera were associated with the metabolic signatures. In conclusion, the beneficial effects of XOS on hepatic steatosis involved decreased adipose tissue inflammation and likely improved insulin signaling, which were further associated with fecal metabolites and GM. Full article

High-fat diet (HFD) induces inflammation and microbial dysbiosis, which are components of the metabolic syndrome. Nutritional strategies can be a valid tool to prevent metabolic and inflammatory diseases. The aim of the present study was to evaluate if the chronic intake of pistachio prevents obesity-associated inflammation and dysbiosis in HFD-fed mice. Three groups of male mice (four weeks old; n = 8 per group) were fed for 16 weeks with a standard diet (STD), HFD, or HFD supplemented with pistachios (HFD-P; 180 g/kg of HFD). Serum, hepatic and adipose tissue inflammation markers were analyzed in HFD-P animals and compared to HFD and STD groups. Measures of inflammation, obesity, and intestinal integrity were assessed. Fecal samples were collected for gut microbiota analysis. Serum TNF-α and IL-1β levels were significantly reduced in HFD-P compared to HFD. Number and area of adipocytes, crown-like structure density, IL-1β, TNF-α, F4-80, and CCL-2 mRNA expression levels were significantly reduced in HFD-P subcutaneous and visceral adipose tissues, compared to HFD. A significant reduction in the number of inflammatory foci and IL-1β and CCL-2 gene expression was observed in the liver of HFD-P mice compared with HFD. Firmicutes/Bacteroidetes ratio was reduced in HFD-P mice in comparison to the HFD group. A pistachio diet significantly increased abundance of healthy bacteria genera such as Parabacteroides, Dorea, Allobaculum, Turicibacter, Lactobacillus, and Anaeroplasma, and greatly reduced bacteria associated with inflammation, such as Oscillospira, Desulfovibrio, Coprobacillus, and Bilophila. The intestinal conductance was lower in HFD-P mice than in the HFD mice, suggesting an improvement in the gut barrier function. The results of the present study showed that regular pistachio consumption improved inflammation in obese mice. The positive effects could be related to positive modulation of the microbiota composition. Full article

Epidemiological studies provide strong evidence that obesity and the associated adipose tissue inflammation are risk factors for breast cancer; however, the molecular mechanisms are poorly understood. We evaluated the effect of a high-fat/high-calorie diet on mammary carcinogenesis in the immunocompetent MMTV-PyMT murine model. Four-week old female mice (20/group) were randomized to receive either a high-fat (HF; 60% kcal as fat) or a low-fat (LF; 16% kcal) diet for eight weeks. Body weights were determined, and tumor volumes measured by ultrasound, each week. At necropsy, the tumors and abdominal visceral fat were weighed and plasma collected. The primary mammary tumors, adjacent mammary fat, and lungs were preserved for histological and immunohistochemical examination and quantification of infiltrating macrophages, crown-like structure (CLS) formation, and microvessel density. The body weight gains, visceral fat weights, the primary mammary tumor growth rates and terminal weights, were all significantly greater in the HF-fed mice. Adipose tissue inflammation in the HF group was indicated by hepatic steatosis, pronounced macrophage infiltration and CLS formation, and elevations in plasma monocyte chemoattractant protein-1 (MCP-1), leptin and proinflammatory cytokine concentrations. HF intake was also associated with higher tumor-associated microvascular density and the proangiogenic factor MCP-1. This study provides preclinical evidence in a spontaneous model of breast cancer that mammary adipose tissue inflammation induced by diet, enhances the recruitment of macrophages and increases tumor vascular density suggesting a role for obesity in creating a microenvironment favorable for angiogenesis in the progression of breast cancer. Full article