Hepatic and adipocyte cells respond differentially to iron overload, hypoxic and inflammatory challenge

Colonic Coffee Phenols Metabolites, Dihydrocaffeic, Dihydroferulic, and Hydroxyhippuric Acids Protect Hepatic Cells from TNF-α-Induced Inflammation and Oxidative Stress

Coffee presents beneficial health properties, including antiobesity effects. However, its effects on inflammation are controversial. Hydroxycinnamic acids are the main coffee phenolic bioactive compounds. In human bioavailability studies carried out with coffee, among the most abundant compounds found in urine and plasma were the colonic metabolites, dihydrocaffeic (DHCA), dihydroferulic (DHFA), and hydroxyhippuric (HHA) acids. To understand the hepato-protective potential of these three compounds, we tested whether treatment with realistic concentrations (0.5-10 µM) were effective to counteract inflammatory process and oxidative status induced by tumor necrosis factor α (TNF-α). First, we established a novel model of inflammation/oxidation using TNF-α and HepG2 cells. Afterwards, we evaluated the activity of DHCA, DHFA, and HHA against the inflammatory/oxidative challenge through the determination of the inflammatory mediators, interleukins (IL)-6, and IL-8 and chemokines, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1, as well as the levels of biomarkers of oxidative stress, such as reactive oxygen species, reduced glutathione, and the antioxidant enzymes glutathione peroxidase and reductase. Results showed that all three compounds have a potential hepato-protective effect against the induced inflammatory/oxidative insult.

Shuxie-1 Decoction Alleviated CUMS -Induced Liver Injury via IL-6/JAK2/STAT3 Signaling

Introduction: Chronic stress has been shown to cause liver damage in addition to psychological depression. Besides, drug-induced liver injury is frequently caused by antidepressants. Shuxie-1 decoction (SX-1) is a formula of traditional Chinese medicine commonly used in nourishing liver blood, and relieving depression. However, the underlying molecular mechanism remains unclear. Therefore, this study was designed to explore the effects and mechanisms of SX-1 in treating chronic stress-induced depression as well as liver injury.

Methods: Chronic unpredictable mild stress (CUMS) was applied to male Wistar rats for 4 weeks, with or without administration of SX-1 at low-dose and high-dose for 6 weeks, using Fluoxetine (Flu) as a positive control. Body weight was monitored once every 2 weeks. In the sixth week, the sugar preference test and open field test were carried out to evaluate the depression status. After that, the serum and liver tissues were collected. The quality control of SX-1 decoctions and drug-containing serum was controlled by UHPLC-QE-MS. The cell viability was measured by Cell Counting Kit-8 (CCK8). Enzyme-linked immunosorbent assay (Elisa), Western Blot and immunohistochemistrical staining was obtained to detect the protein levels in the plasma and the hepatic tissues, respectively.

Results: CUMS led to decreased 1) body weight, 2) the preference for sugar water, 3) the desire to explore in open field, and increased serum levels of corticosterone. All these factors were completely reversed by SX-1 treatment. Hematoxylin-eosin staining (HE) showed that SX-1 improved the hepatocyte vacuolization in CUMS treated rats, decreased the serum levels of alanine aminotransferase (ALT) and the deposition of type I collagen (Col I) in hepatocytes as well. CUMS increased the levels of hepatic Interleukin-6 (IL-6), and provoked the activation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), which was abrogated by SX-1 treatment. Cobalt chloride (CoCl₂) increased the protein expression of IL-6 and p-STAT3 in AML12 cells. Besides, nuclear pyknosis was observed under electron microscope, which were recovered after rat SX serum.

Conclusion: SX-1 effectively ameliorated CUMS-induced depression-like behaviors as well as hepatic injuries, probably by the blockade of hepatic IL-6/JAK2/STAT3 signaling.

Nutritional impact of bariatric surgery: a comparative study of Roux-en-Y Gastric Bypass and Sleeve gastrectomy between patients from the public and private health systems

PURPOSE

To compare the nutritional status follow up of patients who underwent Roux-en-Y gastric bypass (BGYR) and Sleeve gastrectomy (SG) in hospitals of the private and public health systems, in Pernambuco.

METHODS

This study included patients who underwent bariatric surgery in the public and private health systems, in Pernambuco, from 2008 to 2016. Anthropometric and biochemical (hemoglobin, B12, iron and ferritin) data were evaluated in the preoperative period and at 3, 6 and 12 months after the operation.

RESULTS

There were no significant difference between patients seen at the two health systems regarding the levels of hemoglobin, iron, anemia and vitamin B12. Patients who underwent the RYGB, presented with iron deficiency which was significantly lower for those in the private system, but only at the 3 month evaluation. Low levels of ferritin were observed at the 6 month evaluation, and patients in the private health system presented with the highest ferritin deficiency. The rate of surgical success was significantly higher in those patients undergoing the RYGB at the private system.

CONCLUSIONS

After a 12-month bariatric surgery follow-up, there was no statistically significant difference regarding micronutrient deficiency between patients followed up at the private and public health systems.

Quantitative magnetic resonance imaging evaluation of hepatic fat content with iron deposition: will it be disturbed?

Objective

To explore noninvasive assessment of liver fat content with iron deposition using magnetic resonance (MR) quantitative technology.

Methods

A water–fat phantom with iron deposition containing 63 vials with predetermined fat percentages and iron concentrations was constructed. Thirty-three patients underwent fat quantitative MR examinations. The fat fraction (FF) was determined by three Dixon techniques. Pathological evaluation findings and the steatosis area rate (SAR) were used as the gold standards.

Results

FF_IOP and FF_LAVA-Flex significantly differed from FF_TEST for iron concentrations of 1 to 30 µg/mL and fat components of 10% to 80%. Using the three Dixon techniques, FF_IOP was 15.76% ± 6.98%, FF_LAVA-Flex was 16.71% ± 6.77%, and FF_{IDEAL IQ} was 13.18% ± 6.42% in patients without liver cirrhosis; these values in patients with liver cirrhosis were 20.35% ± 6.11%, 20.89% ± 8.49%, and 12.86% ± 4.00%, respectively. The SAR in patients without and with liver cirrhosis was 11.31% ± 5.89% and 9.84% ± 4.17%, respectively. There were significant positive correlations between FF_{IDEAL IQ} and SAR with or without liver cirrhosis.

Conclusion

Iron deposition must be considered when using quantitative MR techniques to evaluate the hepatic fat content. Compared with the IOP and LAVA-Flex techniques, the IDEAL IQ technique has more stability and accuracy in measurement of the hepatic fat content, free from iron deposition.

Could de-stressing the brain be the solution for long-term weight loss?

The obese brain is stressed and inflamed. This is mainly at the level of neurons and glial cells in the hypothalamus: a brain region where the adipokine leptin acts to control feeding and body weight. Relieving hypothalamic neuronal endoplasmic reticulum (ER) stress with the natural small molecule drugs celastrol or withaferin-A reverses the leptin resistance commensurate with obesity, producing a degree of weight loss found only with bariatric surgery. Here, recent evidence from rodent models of vertical sleeve gastrectomy (VSG) is brought to the fore which suggests that this particular bariatric surgical procedure may work in a similar fashion to celastrol and withaferin-A alongside remedying hypothalamic inflammation and gliosis. Thus, restoring and preserving healthy hypothalamic neuronal and glial cell function, be it by pharmacological or surgical means, ensures a negative energy balance in an environment constructed to promote a one - possibly through re-establishing communication between adipose tissue and the brain.

Expression of genes associated with inflammation and iron metabolism in 3T3-L1 cells induced with macrophages-conditioned medium, glucose and iron

Obesity is characterized by a chronic inflammatory process, with an increased volume of total adipose tissue, especially visceral, which secretes pro-inflammatory cytokines such as TNF-α and IL-6. Hepcidin (Hpc), a main iron metabolism regulator, is synthetized by an IL-6 stimuli, among others, in liver and adipose tissue, favoring an association between the inflammatory process and iron metabolism. Still there are questions remain regarding the interaction of these factors. Our aim was to study the effect of a macrophage-conditioned medium (MCM) on adipocyte cells challenged with glucose and/or iron. We studied the mRNA relative abundance of genes related to inflammation in differentiated 3T3-L1 cells challenged with Fe (40 µM), glucose (20 mM) or Fe/glucose (40 µM/20 mM) with or without MCM for 24 h. We also measured the intracellular iron levels under these conditions. Our results showed that when adipocytes were challenged with MCM, glucose and/or Fe, the intracellular iron and mRNA levels of pro-inflammatory cytokines increased. These responses were higher when all the stimuli were combined with MCM from macrophages. Thus, we showed that combined high glucose/high Fe alone or with MCM may contribute to an increase on intracellular iron and inflammatory response in 3T3-L1 differentiated cells, by increased mRNA levels of IL-6, TNF-α, MCP-1, Hpc and reducing adiponectin levels, enhancing the inflammatory processes.

Downregulation of Mitofusin 2 in Placenta Is Related to Preeclampsia

Background. Mitofusin 2 (Mfn2) is a novel mitochondrial protein that is implicated in cellular proliferation and metabolism; however, the role of Mfn2 in preeclampsia (PE) remains unknown. This study aimed to explore the relationship between Mfn2 and PE. Method. Preeclamptic and normal pregnancies were enrolled in a comparative study. The expression of Mfn2 in placenta was detected by qRT-PCR. And the mitochondrial function was detected by ATP assay. Then TEV-1 cells were cultured in hypoxic conditions. mRNA and protein expressions of Mfn2 were detected by qRT-PCR and western blot separately. Cells' viability was detected by MTT. And the mitochondrial function was detected by ATP and mitochondrial membrane potential (MMP) assay. We further knocked down the Mfn2 gene in TEV-1 cells and evaluated the cells' viability. Results. Mfn2 and ATP expressions were significantly decreased in preeclamptic placentae compared to normal placentae. Mfn2 expression level and the viability of TEV-1 cells were reduced during hypoxic conditions. TEV-1 cells' viability, ATP, and MMP levels were also significantly decreased after knockdown of the Mfn2 gene. Conclusions. These results suggest that defects in Mfn2 could cause mitochondrial dysfunction and decrease trophoblastic cells' viability. Therefore, Mfn2 may be functionally involved in the pathogenesis of PE.

Iron primes 3T3-L1 adipocytes to a TLR4-mediated inflammatory response

OBJECTIVE

Iron participates in several mechanisms involving inflammation and innate immunity, yet the dysregulation of its homeostasis is a major cause of metabolic syndrome. Adipocytes should play a major role in iron metabolism, as an impairment in iron turnover is closely related to insulin resistance, obesity, and type 2 diabetes. The aim of this study was to investigate the role of iron in an in vitro-inflamed adipocyte model.

METHODS

Gene expression of tumor necrosis factor-α, interleukin-6, inflammatory chemokines (CCL3, CCL4, and CXCL12), and molecules involved in iron metabolism were evaluated in an in vitro mouse 3T3-L1 cell model. Cells underwent treatment with FeSO4 heptahydrate and lipopolysaccharide (LPS) stimulation. Toll-like receptor 4 (TLR4) membrane expression, lipid droplet immunohystochemistry, and lipolysis were also evaluated.

RESULTS

Iron sulphate heptahydrate elicited gene expression of hepcidin, hemojuvelin, and ferroportin at different time courses. Additionally, it activated lipolysis but did not trigger any adipokine gene expression. When cells treated with physiological doses of iron were also stimulated with LPS, an enhancement in the LPS-induced gene expression of cytokines and chemokines was observed. The enhancement occurred with different patterns depending on different time courses and investigated genes, showing its maximal effect for IL-6 gene expression.

CONCLUSIONS

FeSO4 heptahydrate at a relatively physiological dose, induced gene expression of iron modulatory proteins and also enhanced RNA transcripts of several inflammatory cytokines and chemokines through a priming/synergistic mechanism involving membrane TLR4.

Dysregulated iron homeostasis is strongly associated with multiorgan failure and early mortality in acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is an ailment with high incidence of multiorgan failure (MOF) and consequent mortality. Dysregulated iron homeostasis and macrophage dysfunction are linked to increased incidence of MOF. We investigated whether a panel of circulating iron-regulating proteins are associated with development of MOF and can predict 15- or 30-day mortality in ACLF patients. One hundred twenty patients with ACLF, 20 patients with compensated cirrhosis, and 20 healthy controls were studied. Relative protein expression profiling was performed in the derivative cohort and confirmed in the validation cohort. A panel of iron regulators and indices were determined. Multiparametric flow cytometry for quantitation of labile iron pool (LIP) was performed. Validation studies confirmed lower serum transferrin (Tf) and ceruloplasmin levels in ACLF and ACLF-MOF, compared to patients with cirrhosis and controls (P < 0.01). Serum iron and ferritin levels were markedly elevated (P < 0.001; P < 0.05) and hepcidin levels were lower (P < 0.001) in ACLF patients with MOF than those without and other groups (P < 0.001). Percentage Tf saturation (%SAT) was higher in ACLF-MOF (39.2%; P < 0.001) and correlated with poor outcome (hazard ratio: 6.970; P < 0.01). Intracellular LIP indices were significantly elevated in the subsets of circulating macrophages in ACLF-MOF, compared to other groups (P < 0.01). Whereas expression of iron-regulatory genes was markedly down-regulated, genes related to endoplasmic reticulum stress, apoptosis, and inflammation were up-regulated in ACLF patients, compared to patients with cirrhosis. Severe dysregulation of autophagy mechanisms was also observed in the former.

CONCLUSIONS

Iron metabolism and transport are severely deranged in ACLF patients and more so in those with MOF. %SAT, circulating hepcidin, and LIP in macrophages correlate with disease severity and %SAT could be used for early prognostication in ACLF patients.

Neurotoxic effects of iron overload under high glucose concentration

Iron overload can lead to cytotoxicity, and it is a risk factor for diabetic peripheral neuropathy. However, the underlying mechanism remains unclear. We conjectured that iron overload-induced neurotoxicity might be associated with oxidative stress and the NF-E2-related factor 2 (Nrf2)/ARE signaling pathway. As an in vitro cellular model of diabetic peripheral neuropathy, PC12 cells exposed to high glucose concentration were used in this study. PC12 cells were cultured with ferric ammonium citrate at different concentrations to create iron overload. PC12 cells cultured in ferric ammonium citrate under high glucose concentration had significantly low cell viability, a high rate of apoptosis, and elevated reactive oxygen species and malondialdehyde levels. These changes were dependent on ferric ammonium citrate concentration. Nrf2 mRNA and protein expression in the ferric ammonium citrate groups were inhibited markedly in a dose-dependent manner. All changes could be inhibited by addition of deferoxamine. These results indicate that iron overload aggravates oxidative stress injury in neural cells under high glucose concentration and that the Nrf2/ARE signaling pathway might play an important role in this process.

Design considerations of iron-based nanoclusters for noninvasive tracking of mesenchymal stem cell homing

Stem-cell-based therapies have attracted considerable interest in regenerative medicine and oncological research. However, a major limitation of systemic delivery of stem cells is the low homing efficiency to the target site. Here, we report a serendipitous finding that various iron-based magnetic nanoparticles (MNPs) actively augment chemokine receptor CXCR4 expression of bone-marrow-derived mesenchymal stem cells (MSCs). On the basis of this observation, we designed an iron-based nanocluster that can effectively label MSCs, improve cell homing efficiency, and track the fate of the cells in vivo. Using this nanocluster, the labeled MSCs were accurately monitored by magnetic resonance imaging and improved the homing to both traumatic brain injury and glioblastoma models as compared to unlabeled MSCs. Our findings provide a simple and safe method for imaging and targeted delivery of stem cells and extend the potential applications of iron-based MNPs in regenerative medicine and oncology.

The role of adipocytes in the modulation of iron metabolism in obesity

A tight relationship between iron deficiency and obesity is known to exist. The chronic low-grade inflammation that characterizes obesity enhances hepcidin production, the principal regulator of iron availability. Adipose tissue is known to secret interleukin-6 and leptin that triggers hepcidin production. It was found that adipose tissue also expresses hepcidin and hemojuvelin, a regulator of hepcidin production. These recent findings suggest that adipose tissue may have an important role in erythropoiesis particularly on obesity that is still poorly clarified. This paper discusses these findings and how they can modulate erythropoiesis.

Excess iron undermined bone load-bearing capacity through tumor necrosis factor-α-dependent osteoclastic activation in mice

Iron overload has been associated with bone mass loss. To elucidate the effects of excess iron on bone metabolism, an iron-overloading mouse model was established by administering iron-dextran at 250 mg/kg to female BALB/c mice. After 4 weeks, the mice were sacrificed and the biomechanical properties of the femurs were examined. The results suggested a notable decrease of the maximal bending stress and the modulus of bending elasticity in the femurs obtained from the excess iron-treated mice compared to the control mice. The levels of the serum osteocalcin, C-telopeptide of type I collagen (CTX-1) and tumor necrosis factor-α (TNF-α) were measured in order to investigate the underlying mechanism responsible for the excess iron-induced bone strength reduction. Overall, the results suggested that iron overload resulted in a marked reduction of bone load-bearing capacity through a TNF-triggered osteoclast differentiation and resorption mechanism.