The benefits of restraint: a pivotal role for IL-13 in hepatic glucose homeostasis

Disruption of gut barrier integrity and host-microbiome interactions underlie MASLD severity in patients with type-2 diabetes mellitus

Aberration of the "gut-liver axis" contributes to the development and progression of metabolic dysfunction-associated steatotic liver disease (MASLD). Here, we use multi-omics to analyze the gut microbiota composition and metabolic profile of patients with type-2 diabetes mellitus (T2DM). T2DM patients were screened for liver disease by blood tests, ultrasound, and liver stiffness measurements. Stool microbiota was analyzed by 16S rRNA gene sequencing; metabolomic profiling by Nuclear Magnetic Resonance spectroscopy and Ultra-High Performance-Mass Spectrometry. Microbiome and metabolic signatures were analyzed in the whole cohort and in matched subsets to identify signatures specific for steatosis (MASLD±) or fibrosis (Fibrosis±). Gut permeability was assessed in-vitro using monolayers of MDCK cells and trans-epithelial electric resistance (TEER). Cytokine profile was assessed in serum and stools.Overall, 285 patients were enrolled: 255 serum, 252 urine and 97 stool samples were analyzed. Anaeroplasma and Escherichia/Shigella ASVs were higher, while Butyricicoccus ASVs were lower in those with normal liver. In MASLD±, Butyricicoccus ASV was significantly higher in those with steatosis. In the Fibrosis±, Butyricicoccus ASV was significantly lower in those with fibrosis. Glycochenodeoxycholic acid-3-sulfate (G-UDCA-3S) appeared to be higher in MASLD with fibrosis. Fecal water from patients with MASLD and fibrosis caused the greatest drop in the TEER vs those with normal liver; this was reversed with protease inhibitors. Finally, fecal IL-13 was lower in MASLD with fibrosis. We identified microbiome signatures which were specific for steatosis and fibrosis and independent of other metabolic risk factors. Moreover, we conclude that protease-related gut permeability plays a role in those MASLD patients with fibrosis, and that disease progression is linked to a gut-liver axis which is at least partially independent of T2DM.

Combinatory Effect and Modes of Action of Chrysin and Bone Marrow-Derived Mesenchymal Stem Cells on Streptozotocin/Nicotinamide-Induced Diabetic Rats

The purpose of this study was to see how chrysin and/or bone marrow-derived mesenchymal stem cells (BM-MSCs) affected streptozotocin (STZ)/nicotinamide (NA)-induced diabetic rats as an animal model of type 2 diabetes mellitus (T2DM). Male Wistar rats were given a single intraperitoneal (i.p.) injection of 60 mg STZ/kg bodyweight (bw) 15 min after an i.p. injection of NA (120 mg/kg bw) to induce T2DM. The diabetic rats were given chrysin orally at a dose of 100 mg/kg bw every other day, BM-MSCs intravenously at a dose of 1 × 106 cells/rat/week, and their combination for 30 days after diabetes induction. The rats in the diabetic group displayed impaired oral glucose tolerance and a decrease in liver glycogen content and in serum insulin, C-peptide, and IL-13 levels. They also had significantly upregulated activities in terms of liver glucose-6-phosphatase and glycogen phosphorylase and elevated levels of serum free fatty acids, IL-1β, and TNF-α. In addition, the diabetic rats exhibited a significant elevation in the adipose tissue resistin protein expression level and a significant decrease in the expression of adiponectin, insulin receptor-beta subunit, insulin receptor substrate-1, and insulin receptor substrate-2, which were associated with a decrease in the size of the pancreatic islets and in the number of β-cells and insulin granules in the islets. The treatment of diabetic rats with chrysin and/or BM-MSCs significantly improved the previously deteriorated alterations, with chrysin combined with BM-MSCs being the most effective. Based on these findings, it can be concluded that combining chrysin with BM-MSCs produced greater additive therapeutic value than using them separately in NA/STZ-induced T2DM rats.

Increased Secreted Frizzled-Related Protein 5 mRNA Expression in the Adipose Tissue of Women with Nonalcoholic Fatty Liver Disease Associated with Obesity

Secreted frizzled-related protein 5 (SFRP5) is an anti-inflammatory adipocytokine secreted by adipocytes that seems to be linked with nonalcoholic fatty liver disease (NAFLD). We aimed to evaluate the role of the SFRP5-wingless-MMTV integration site family member 5a (WNT5A) pathway, closely related to adipogenesis, in subcutaneous (SAT) and visceral adipose tissues (VAT) and its relationship with obesity-related NAFLD. Our cohort was composed of 60 women with morbid obesity (MO), who underwent hypocaloric diet, subclassified according to their hepatic histopathology and 15 women with normal weight. We observed increased SFRP5 mRNA expression in VAT and lower WNT5A expression in SAT in MO compared to normal weight. We found elevated SFRP5 expression in nonalcoholic steatohepatitis (NASH) in SAT and in mild simple steatosis (SS) and NASH in VAT. We observed higher WNT5A expression in SS compared to normal liver in SAT, and a peak of WNT5A expression in mild SS. To conclude, we reported increased SFRP5 mRNA expression in SAT and VAT of NAFLD-related to obesity subjects, suggesting an implication of the SFRP5-WNT5A pathway in NAFLD pathogenesis, probably due to the adipose tissue-liver axis. Since the mechanisms by which this potential interaction takes place remain elusive, more research in this field is needed.

Chronic inflammation involves CCL11 and IL-13 to facilitate the development of liver cirrhosis and fibrosis in chronic hepatitis B virus infection

The pathogenesis involving non-alcoholic fatty liver disease (NAFLD) in the context of chronic HBV (CHB) virus infection requires to be understood for developing improved modalities of diagnosis and treatment. We retrospectively investigated the association between NAFLD and CHB virus infection in the context of liver fibrosis. Among the 522 consecutive CHB patients who underwent transient elastography between years 2013 and 2016, we studied 455 subjects in the current investigation. Controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) scores were generally higher in patients with steatosis and fibrosis or cirrhosis. Antiviral treatment had significantly reduced the hepatitis B virus (HBV) viral load. Other liver function markers showed a significant positive correlation with both CAP and LSM scores. Plasma IL-13 was independently associated with increased CAP score where every increase of 1 unit of IL-13 was associated with an increase in CAP score by 0.98 unit. CCL11 was independently associated with LSM with every increase of CCL11 by a unit that, in turn, was associated with an increase of LSM score. We found that there was a high concurrence of NAFLD among patients with CHB virus infection. The presence of metabolic syndrome and chronic inflammation in CHB virus-infected patients were two independent factors that led to the progression of liver cirrhosis, with IL-13 playing the key role in linking the metabolic with the inflammatory components.

Limiting Dietary Sugar Improves Pediatric Sinonasal Symptoms and Reduces Inflammation

Excessive sugar consumption is associated with many chronic inflammatory diseases in adults. The effects of excessive sugar consumption in children have not been determined. In this study, we hypothesized that sinonasal symptoms and proinflammatory cytokine levels would be related and could be altered through reduction in sugar-sweetened beverage (SSB) consumption. To test this, we conducted a pilot study involving behavior modification and a 2-week follow-up. Seventeen children participants were recruited, and eleven completed the study. The experimental group presented with chronic nasal congestion or rhinorrhea defined by daily symptoms without acute illness for at least 3 months. The control group presented for non-nasal problems. Both groups received counseling to decrease SSB consumption. The Sinus and Nasal Quality of Life (SN-5) Survey was administered, and a blood sample was obtained by venipuncture at baseline and 2 weeks after counseling. Participants kept a 2-week food diary to document sugar intake. Serum lipid profile and inflammatory cytokines were measured. The experimental group reduced daily sugar intake, 46% versus 11% in the control. Baseline SN-5 scores were significantly worse in the experimental group and normalized to controls after intervention. Inflammatory cytokine levels were not different at baseline, but the experimental group significantly reduced in proinflammatory markers and increased the levels of anti-inflammatory markers after intervention. Our pilot data demonstrate higher sugar consumption may be associated with increased inflammatory stress and sinonasal symptoms. Reducing SSB and controlling inflammation in early childhood may have future health benefits.

Modulation of the IL-33/IL-13 Axis in Obesity by IL-13Rα2

In obesity, IL-13 overcomes insulin resistance by promoting anti-inflammatory macrophage differentiation in adipose tissue. Endogenous IL-13 levels can be modulated by the IL-13 decoy receptor, IL-13Rα2, which inactivates and depletes the cytokine. In this study, we show that IL-13Rα2 is markedly elevated in adipose tissues of obese mice. Mice deficient in IL-13Rα2 had high expression of IL-13 response markers in adipose tissue, consistent with increased IL-13 activity at baseline. Moreover, exposure to the type 2 cytokine-inducing alarmin, IL-33, enhanced serum and tissue IL-13 concentrations and elevated tissue eosinophils, macrophages, and type 2 innate lymphoid cells. IL-33 also reduced body weight, fat mass, and fasting blood glucose levels. Strikingly, however, the IL-33–induced protection was greater in IL-13Rα2–deficient mice compared with wild-type littermates, and these changes were largely attenuated in mice lacking IL-13. Although IL-33 administration improved the metabolic profile in the context of a high fat diet, it also resulted in diarrhea and perianal irritation, which was enhanced in the IL-13Rα2–deficient mice. Weight loss in this group was associated with reduced food intake, which was likely related to the gastrointestinal effects. These findings outline both potentially advantageous and deleterious effects of a type 2–skewed immune response under conditions of metabolic stress, and identify IL-13Rα2 as a critical checkpoint in adipose tissues that limits the protective effects of the IL-33/IL-13 axis in obesity.

Excessive Endoplasmic Reticulum Stress Correlates with Impaired Mitochondrial Dynamics, Mitophagy and Apoptosis, in Liver and Adipose Tissue, but Not in Muscles in EMS Horses

Nowadays, endocrine disorders have become more frequent in both human and veterinary medicine. In horses, reduced physical activity combined with carbohydrate and sugar overload may result in the development of the so-called equine metabolic syndrome (EMS). EMS is characterized by insulin resistance, hyperinsulinemia, elevated blood triglyceride concentrations and usually obesity. Although the phenotypic features of EMS individuals are well known, the molecular mechanism underlying disease development remains elusive. Therefore, in the present study, we analyzed insulin-sensitive tissues, i.e., muscles, liver and adipose tissue in order to evaluate insulin resistance and apoptosis. Furthermore, we assessed mitochondrial dynamics and mitophagy in those tissues, because mitochondrial dysfunction is linked to the development of metabolic syndrome. We established the expression of genes related to insulin resistance, endoplasmic reticulum (ER) stress and mitochondria clearance by mitophagy using RT-PCR and Western blot. Cell ultrastructure was visualized using electron transmission microscopy. The results indicated that adipose tissue and liver of EMS horses were characterized by increased mitochondrial damage and mitophagy followed by triggering of apoptosis as mitophagy fails to restore cellular homeostasis. However, in muscles, apoptosis was reduced, suggesting the existence of a protective mechanism allowing that tissue to maintain homeostasis.

Praziquantel treatment after Schistosoma japonicum infection maintains hepatic insulin sensitivity and improves glucose metabolism in mice

BACKGROUND

Epidemiological studies in China have revealed that Schistosoma japonicum infection is inversely correlated with metabolic syndrome, even after repeated chemotherapy with praziquantel (PZQ). We investigated the effect of chronic S. japonicum infection, PZQ chemotherapy, and soluble egg antigen (SEA) treatment on whole-body metabolic homeostasis and hepatic insulin sensitivity in mouse models.

RESULTS

Infection with S. japonicum was found to increase whole-body and hepatic insulin sensitivity in mice. PZQ chemotherapy significantly improved the physiological status of infected mice, maintaining Th2 immune-deviation and enhancing hepatic insulin sensitivity. Multiple linear regression analysis revealed positive correlations between anti-inflammatory cytokine expression and insulin signalling-related genes in the liver, as demonstrated by an in vitro stimulated hepatic cell line with IL-13 and IL-22. SEA treatment also improved the glucose tolerance and insulin sensitivity in Lepr ^db/db mice.

CONCLUSIONS

This study indicated that chronic S. japonicum infection with PZQ chemotherapy and SEA treatment can regulate metabolic homeostasis and protect against metabolic syndrome by promoting Th2 and regulatory responses in the liver.

IL-4 mRNA Is Downregulated in the Liver of Pancreatic Cancer Patients Suffering from Cachexia

BACKGROUND

Interleukin-4 (IL-4) together with interleukin-13 (IL-13) play an important role in inflammation and wound repair, and are known to be upregulated in human skeletal muscle after strenuous physical exercise. Additionally, these cytokines may act as autocrine growth factors in pancreatic cancer cells. We hypothesize that IL-4, IL-13, and their corresponding receptors are involved in mechanism of cancer cachexia.

METHODS

Tissue samples from human skeletal muscle, white fat, liver, healthy pancreas, and pancreatic ductal adenocarcinoma were analyzed by quantitative real-time polymerase chain reaction for mRNA expression levels of IL-4, IL-13, IL-4 receptor α, and IL-13 receptor α1.

RESULTS

We demonstrate for the first time that liver IL-4 mRNA is downregulated in vivo in patients with pancreatic cancer and cachexia. Additionally, IL-4 mRNA in the liver inversely correlated with musculus psoas thickness.

CONCLUSION

We speculate that suppression of IL-4 is involved in cancer cachexia, although the exact mechanisms have to be further elucidated.