The Potential Role of Iron and Copper in Pediatric Obesity and Nonalcoholic Fatty Liver Disease

Pro- and anti-inflammatory cytokines are the game-changers in childhood obesity-associated metabolic disorders (diabetes and non-alcoholic fatty liver diseases)

Childhood obesity is a chronic inflammatory epidemic that affects children worldwide. Obesity affects approximately 1 in 5 children worldwide. Obesity in children can worsen weight gain and raise the risk of obesity-related comorbidities like diabetes and non-alcoholic fatty liver disease (NAFLD). It can also negatively impact the quality of life for these children. Obesity disrupts immune system function, influencing cytokine (interleukins) balance and expression levels, adipokines, and innate and adaptive immune cells. The altered expression of immune system mediators, including interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-17 (IL-17), interleukin-18 (IL-18), transforming growth factor (TGF), tumor necrosis factor (TNF), and others, caused inflammation, progression, and the development of pediatric obesity and linked illnesses such as diabetes and NAFLD. Furthermore, anti-inflammatory cytokines, including interleukin-2 (IL-2), have been shown to have anti-diabetes and IL-1 receptor antagonist (IL-1Ra) anti-diabetic and pro-NAFLFD properties, and interleukin-10 (IL-10) has been shown to have a dual role in managing diabetes and anti-NAFLD. In light of the substantial increase in childhood obesity-associated disorders such as diabetes and NAFLD and the absence of an effective pharmaceutical intervention to inhibit immune modulation factors, it is critical to consider the alteration of immune system components as a preventive and therapeutic approach. Thus, the current review focuses on the most recent information regarding the influence of pro- and anti-inflammatory cytokines (interleukins) and their molecular mechanisms on pediatric obesity-associated disorders (diabetes and NAFLD). Furthermore, we discussed the current therapeutic clinical trials in childhood obesity-associated diseases, diabetes, and NAFLD.

Overweight, Obesity, Hypertriglyceridemia, and Insulin Resistance Are Positively Associated with High Serum Copper Levels in Mexican Adults

Recently, the role of trace elements in the pathophysiology of obesity, insulin resistance (IR), and metabolic diseases has been explored. In this cross-sectional study, we aimed to assess the association of overweight, obesity, and cardiometabolic traits with serum copper (Cu) levels in 346 Mexican adults. Serum Cu level was measured by inductively coupled plasma mass spectrometry (ICP-MS). Anthropometrical data were collected, and biochemical parameters were measured. The triglyceride-glucose (TyG) index was used as a surrogate marker to evaluate IR. Overweight and obesity status was positively associated with the serum Cu level (β = 19.434 ± 7.309, p = 0.008). Serum Cu level was observed to have a positive association with serum triglycerides level (β = 0.160 ± 0.045, p < 0.001) and TyG (β = 0.001 ± 0.001, p < 0.001). Additionally, high serum Cu level was positively associated with overweight and obesity status (odds ratio [OR] = 1.9, 95% confidence interval [95% CI] 1.1-3.4, p = 0.014), hypertriglyceridemia (OR = 3.0, 95% CI 1.7-5.3, p < 0.001), and IR (OR = 2.6, 95% CI 1.4-4.6, p = 0.001). In conclusion, our results suggest that overweight, obesity, hypertriglyceridemia, and IR are positively associated with serum Cu levels in Mexican adults.

Elucidating cuproptosis in metabolic dysfunction-associated steatotic liver disease

Emerging research into metabolic dysfunction-associated steatotic liver disease (MASLD) up until January 2024 has highlighted the critical role of cuproptosis, a unique cell death mechanism triggered by copper overload, in the disease's development. This connection offers new insights into MASLD's complex pathogenesis, pointing to copper accumulation as a key factor that disrupts lipid metabolism and insulin sensitivity. The identification of cuproptosis as a significant contributor to MASLD underscores the potential for targeting copper-mediated pathways for novel therapeutic approaches. This promising avenue suggests that managing copper levels could mitigate MASLD progression, offering a fresh perspective on treatment strategies. Further investigations into how cuproptosis influences MASLD are essential for unraveling the detailed mechanisms at play and for identifying effective interventions. The focus on copper's role in liver health opens up the possibility of developing targeted therapies that address the underlying causes of MASLD, moving beyond symptomatic treatment to tackle the root of the problem. The exploration of cuproptosis in the context of MASLD exemplifies the importance of understanding metal homeostasis in metabolic diseases and represents a significant step forward in the quest for more effective treatments. This research direction lights path for innovative MASLD management and reversal.

Arbutin alleviates fatty liver by inhibiting ferroptosis via FTO/SLC7A11 pathway

Non-alcoholic fatty liver disease (NAFLD) is a potentially serious disease that affects 30 % of the global population and poses a significant risk to human health. However, to date, no safe, effective and appropriate treatment modalities are available. In recent years, ferroptosis has emerged as a significant mode of cell death and has been found to play a key regulatory role in the development of NAFLD. In this study, we found that arbutin (ARB), a natural antioxidant derived from Arctostaphylos uva-ursi (L.), inhibits the onset of ferroptosis and ameliorates high-fat diet-induced NAFLD in vivo and in vitro. Using reverse docking, we identified the demethylase fat mass and obesity-related protein (FTO) as a potential target of ARB. Subsequent mechanistic studies revealed that ARB plays a role in controlling methylation of the SLC7A11 gene through inhibition of FTO. In addition, we demonstrated that SLC7A11 could alleviate the development of NAFLD in vivo and in vitro. Our findings identify the FTO/SLC7A11 axis as a potential therapeutic target for the treatment of NAFLD. Specifically, we show that ARB alleviates NAFLD by acting on the FTO/SLC7A11 pathway to inhibit ferroptosis.

Micronutrient Deficiency in Children and Adolescents with Obesity-A Narrative Review

Childhood obesity represents a serious public health burden. Despite excessive dietary consumption, children with obesity present high rates of micronutrient deficiencies, such as deficiencies in minerals and specific vitamins; micronutrient deficiencies may have a pathogenic role in obesity-related metabolic comorbidities. In this narrative review, we analyzed the main deficiencies associated with obesity, their clinical consequences, and the evidence about a possible supplementation. Iron; vitamins A, B, C, D, and E; folic acid; zinc; and copper deficiencies represent the most common deficient microelements. The relationship between obesity and multiple micronutrient deficiencies remains unclear, and different mechanisms have been proposed. The medical care plan for pediatric obesity should include food choices with high nutritional content as part of a crucial approach to obesity-related complications. Unfortunately, only a few studies are available regarding the efficacy of oral supplementation or weight loss for treating them; thus, continuous nutritional monitoring is necessary.

Recent advances in the application of ionomics in metabolic diseases

Trace elements and minerals play a significant role in human health and diseases. In recent years, ionomics has been rapidly and widely applied to explore the distribution, regulation, and crosstalk of different elements in various physiological and pathological processes. On the basis of multi-elemental analytical techniques and bioinformatics methods, it is possible to elucidate the relationship between the metabolism and homeostasis of diverse elements and common diseases. The current review aims to provide an overview of recent advances in the application of ionomics in metabolic disease research. We mainly focuses on the studies about ionomic or multi-elemental profiling of different biological samples for several major types of metabolic diseases, such as diabetes mellitus, obesity, and metabolic syndrome, which reveal distinct and dynamic patterns of ion contents and their potential benefits in the detection and prognosis of these illnesses. Accumulation of copper, selenium, and environmental toxic metals as well as deficiency of zinc and magnesium appear to be the most significant risk factors for the majority of metabolic diseases, suggesting that imbalance of these elements may be involved in the pathogenesis of these diseases. Moreover, each type of metabolic diseases has shown a relatively unique distribution of ions in biofluids and hair/nails from patients, which might serve as potential indicators for the respective disease. Overall, ionomics not only improves our understanding of the association between elemental dyshomeostasis and the development of metabolic disease but also assists in the identification of new potential diagnostic and prognostic markers in translational medicine.

Characterization of the Plasmatic and Erythroid Multielemental Biodistribution in Childhood Obesity Using a High-Throughput Method for Size Fractionation of Metal Species

In this chapter, we describe a metallomics method based on protein precipitation under non-denaturing conditions and further analysis by inductively coupled plasma mass spectrometry for high-throughput metal speciation in plasma and erythrocyte samples. This methodology enables to study the total multielemental profile of these biological matrices, as well as to quantify the metal fractions conforming the metallometabolome and the metalloproteome. Furthermore, the analytical coverage comprises several essential and toxic metal elements, namely aluminum, arsenic, cadmium, cobalt, chromium, copper, iron, lithium, manganese, molybdenum, nickel, lead, selenium, vanadium, and zinc. Altogether, the metallomics method here proposed represents an excellent approach to comprehensively characterize the metal biodistribution in human peripheral blood, which would enable to decipher the role of metal homeostasis in health and disease, and particularly in childhood obesity.

Iron overload accelerated lipid metabolism disorder and liver injury in rats with non-alcoholic fatty liver disease

Background/aims

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide. Iron overload has been implicated in chronic non-communicable liver diseases, but its relationship with NAFLD remains unclear. This study aimed to investigate the underlying roles of iron overload in the development of NAFLD.

Methods

Male Sprague Dawley rats were fed with a high-fat diet (HFD) and/or iron for 8, 12, and 20 weeks. Some rats fed with HFD plus iron also received intraperitoneal injection of deferoxamine (DFO) for 8 weeks. Liver steatosis, lipid metabolism and injury were evaluated.

Results

A NAFLD model, including typical liver steatosis, was established by feeding rats with a HFD, while iron overload alone is not enough to induce severe NAFL. Compared with rats fed a HFD, excess iron further increased lipid accumulation, serum levels of lipids, enzymes of liver function, and expression levels of CD36 and FAS in rat liver. In addition, iron overload decreased the activities of antioxidative enzymes in liver compared with HFD rats. The levels of CPT1 and the ratios of p-ACC/ACC were also decreased by iron overload. DFO effectively reversed the abnormal lipid metabolism and liver damage induced by a high-fat, high-iron diet.

Conclusion

A HFD plus iron overload might synergistically aggravate lipid metabolism disorders, liver injury, and oxidative damage, compared with a HFD alone. DFO might help to alleviate lipid metabolism dysfunction and improve the pathogenesis of NAFLD.

Lower serum copper concentrations are associated with higher prevalence of nonalcoholic steatohepatitis: a matched case-control study

BACKGROUND AND AIM

Copper is an essential trace element involved in oxidative stress reactions and energy metabolism. While nonalcoholic fatty liver disease (NAFLD) is closely related to metabolic dysfunction, the role of copper in the development of simple steatosis (NAFL) and nonalcoholic steatohepatitis (NASH) is still unclear. We aimed to compare serum copper levels between patients with simple steatosis and those with NASH.

METHODS AND RESULTS

We studied 102 patients with biopsy-proven NASH (cases) and 102 NAFL controls, who were matched for age, sex, and residential city. Multivariable conditional logistic analysis was performed to explore associations between serum copper levels and the presence of NASH. Serum copper levels were significantly lower in patients with NASH than in those with matched NAFL controls (15.53 ± 2.41 μmol/l vs. 16.34 ± 3.23 μmol/l; P = 0.029). This intergroup difference in serum copper levels was more pronounced in men than in women. The per unit, per SD, and per doubling of serum copper levels were associated, respectively, with an approximately 20, 40, and 90% decrease in risk of having NASH, even after adjustment for potential confounding factors.

CONCLUSION

Lower serum copper concentrations are significantly associated with higher prevalence of NASH among biopsied-proven NAFLD patients, particularly in men.

Sedentary time has a stronger impact on metabolic health than moderate to vigorous physical activity in adolescents with obesity: a cross-sectional analysis of the Beta-JUDO study

BACKGROUND

Relationships between movement-related behaviours and metabolic health remain underexplored in adolescents with obesity.

OBJECTIVES

To compare profiles of sedentary time (more sedentary, SED+ vs. less sedentary, SED-), moderate to vigorous physical activity (MVPA) time (more active, MVPA+ vs. less active, MVPA-) and combinations of behaviours (SED-/MVPA+, SED-/MVPA-, SED+/MVPA+, SED+/MVPA-) in regard to metabolic health.

METHODS

One hundred and thirty-four subjects (mean age 13.4 ± 2.2 yrs, mean body mass index [BMI] 98.9 ± 0.7 percentile, 48.5% females) underwent 24 h/7 day accelerometry, anthropometric, body composition, blood pressure (BP), lipid profile and insulin resistance (IR) assessments.

RESULTS

Metabolic health was better in SED- [lower fat mass (FM) percentage (p < 0.05), blood pressure (BP) (p < 0.05), homeostasis model assessment of insulin resistance (HOMA-IR) (p < 0.001) and metabolic syndrome risk score (MetScore) (p < 0.001), higher high-density lipoprotein-cholesterol (HDL-c) (p = 0.001)] vs. SED+ group and in MVPA+ [lower triglyceridemia (TG), (p < 0.05), HOMA-IR (p < 0.01) and MetScore (p < 0.001), higher HDL-c (p < 0.01)] vs. MVPA- group after adjustment with age, gender, maturation and BMI. SED-/MVPA+ group had the best metabolic health. While sedentary (p < 0.001) but also MVPA times (p < 0.001) were lower in SED-/MVPA- vs. SED+/MVPA+, SED-/MVPA- had lower FM percentage (p < 0.05), HOMA-IR (p < 0.01) and MetScore (p < 0.05) and higher HDL-c (p < 0.05), independently of BMI. Sedentary time was positively correlated with HOMA-IR and Metscore and negatively correlated with HDL-c after adjustment with MVPA (p < 0.05). MVPA was negatively correlated with HOMA-IR, BP and MetScore and positively correlated with HDL-c after adjustment with sedentary time (p < 0.05).

CONCLUSION

Lower sedentary time is associated with a better metabolic health independently of MVPA and might be a first step in the management of pediatric obesity when increasing MVPA is not possible.

Association between Metabolic Syndrome Diagnosis and the Physical Activity-Sedentary Profile of Adolescents with Obesity: A Complementary Analysis of the Beta-JUDO Study

Metabolic syndrome (MetS) is highly prevalent in children and adolescents with obesity and places them at an increased risk of cardiovascular-related diseases. However, the associations between objectively measured movement-related behaviors and MetS diagnosis remain unexplored in youths with obesity. The aim was to compare profiles of sedentary (SED) time (more sedentary, SED+ vs. less sedentary, SED−), moderate to vigorous physical activity (MVPA) time (more active, MVPA+ vs. less active, MVPA−) and combinations of behaviors (SED−/MVPA+, SED−/MVPA−, SED+/MVPA+, SED+/MVPA−) regarding the MetS diagnosis. One hundred and thirty-four adolescents with obesity (13.4 ± 2.2 years) underwent 24 h/7 day accelerometry, waist circumference (WC), blood pressure (BP), high-density lipoprotein-cholesterol (HDL-c), triglycerides (TG) and insulin-resistance (IR) assessments. Cumulative cardiometabolic risk was assessed by using (i) MetS status (usual dichotomic definition) and (ii) cardiometabolic risk z-score (MetScore, mean of standardized WC, BP, IR, TG and inverted HDL-c). SED− vs. SED+ and MVPA+ vs. MVPA− had lower MetS (p < 0.01 and p < 0.001) and MetScore (p < 0.001). SED−/MVPA+ had the lowest risk. While SED and MVPA times were lower in SED−/MVPA− vs. SED+/MVPA+ (p < 0.001), MetScore was lower in SED−/MVPA− independently of body mass index (BMI) (p < 0.05). MVPA, but not SED, time was independently associated with MetS diagnosis (p < 0.05). Both MVPA (p < 0.01) and SED times (p < 0.05) were associated with MetScore independently of each other. A higher MVPA and lower SED time are associated with lower cumulative cardiometabolic risk.

Five Constituents in Psoralea corylifolia L. Attenuate Palmitic Acid-Induced Hepatocyte Injury via Inhibiting the Protein Kinase C-α/Nicotinamide-Adenine Dinucleotide Phosphate Oxidase Pathway

Psoralea corylifolia L. (PC) is a traditional Chinese herb used to treat yang deficiency of the spleen and kidney in pediatric disease. Our previous studies have found that PC can alleviate the liver oxidative stress of juvenile mice with nonalcoholic steatohepatitis (NASH), and its mechanism is related to the inhibition of the protein kinase C-α (PKC-α)/nicotinamide-adenine dinucleotide phosphate oxidase (NOX) signaling pathway. The aim of this study was to confirm the aforementioned drug target in vitro and to conduct preliminary screening for some effective compounds of PC on the treatment of NASH. A primary hepatocyte model of non alcoholic fatty liver disease was established by palmitic acid. The existence of Psoralen, Isopsoralen, Neobavaisoflavone, Isobavachalcone, and Bakuchiol were identified by ultra-performance liquid chromatography. Then, five PC compounds were administered. Intracellular triglyceride and total cholesterol content, the cell supernatant alanine aminotransferase and aspartate aminotransferase, and hepatocellular superoxide anion were examined. The changes of PKC-α/NOX signaling pathways in hepatocytes were also determined. Furthermore, PKC-α activator phorbol 12-myristate 13-acetate was administered for 4 h before Psoralen intervention was conducted again to detect the changes of PKC-α/NOX signaling pathways. Our data demonstrated that Psoralen, Isopsoralen, and Isobavachalcone decreased intracellular content of triglyceride while all five PC compounds improved hepatocellular total cholesterol accumulation and hepatocyte damage in palmitic acid-induced primary hepatocyte model of non alcoholic fatty liver disease. All five PC compounds could also reduce hepatocytic superoxide anion levels, nicotinamide-adenine dinucleotide phosphate/reduced nicotinamide-adenine dinucleotide phosphate ratio, NOX activity as well as p47^phox protein expression and PKCα activation in hepatocytes. Psoralen exhibited the best efficacy but the effectiveness was lost when pre-stimulated by phorbol 12-myristate 13-acetate. The results suggest that Psoralen, Isopsoralen, and Isobavachalcone could improve hepatocyte steatosis; five PC compounds could ameliorate hepatocyte injury, relieve oxidative stress, and downregulate the PKC-α/NOX signaling pathway of hepatocytes. In addition, Psoralen exhibits the best efficacy and a prospective PKC-α inhibitor pharmaceutical activity.

Microarray Expression Profiling and Raman Spectroscopy Reveal Anti-Fatty Liver Action of Berberine in a Diet-Induced Larval Zebrafish Model

Background: The prevalence of non-alcohol fatty liver disease (NAFLD) is increasing in children and adolescents who are mostly resulted from overfeeding. Previous studies demonstrate that berberine (BBR), a compound derived from plant, has beneficial effects on NAFLD in adults but poorly understood in the pediatric population. This study employed a larval zebrafish model to mimic the therapeutic effects of BBR in the pediatric population and the mechanisms underlying its hepatoprotection. Methods: High-cholesterol diet (HCD)-fed zebrafish exposed to BBR at doses of 0, 1, 5, and 25 μM. After the larvae were treated with BBR for 10 days, its effect on hepatic steatosis was evaluated. We introduced Raman imaging and three-dimensional (3D) molecular imaging to detect changes in the biochemical composition and reactive oxygen species (ROS) levels of zebrafish liver. Gene expression microarray was performed to identify differentially expressed genes (DEGs) followed by gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and functional category analysis. Results: BBR (5 and 25 μM) administration prevented HCD-induced liver lipid accumulation in larval zebrafish. The result was further confirmed by the pathological observation. Raman mapping indicated that the biochemical composition in the liver of BBR-treated group shifted to the control. The quantitative analysis of 3D imaging showed that the ROS level was significantly decreased in the liver of BBR-treated larvae. In the livers of the BBR group, we found 468 DEGs, including 172 genes with upregulated expression and 296 genes with downregulated expression. Besides, GO enrichment, KEGG pathway, and functional category analysis showed that various processes related to glucolipid metabolism, immune response, DNA damage and repair, and iron were significantly enriched with DEGs. The expression levels of the crucial genes from the functional analysis were also confirmed by quantitative PCR (qPCR). Conclusion: BBR can significantly improve hepatic steatosis in HCD-fed zebrafish larvae. Its mechanisms might be associated with the regulation of lipid metabolism, oxidative stress, and iron homeostasis. Raman imaging in larval zebrafish might become a useful tool for drug evaluation. Mainly, the gene expression profiles provide molecular information for BBR on the prevention and treatment of pediatric NAFLD.

Serum Ferritin Correlates With Liver Fat in Male Adolescents With Obesity

Non-alcoholic fatty liver disease (NAFLD) contributes essentially to the burden of obesity and can start in childhood. NAFLD can progress to cirrhosis and hepatocellular carcinoma. The early phase of NAFLD is crucial because during this time the disease is fully reversible. Pediatric NAFLD shows unique features of histology and pathophysiology compared to adults. Changes in serum iron parameters are common in adult NAFLD and have been termed dysmetabolic iron overload syndrome characterized by increased serum ferritin levels and normal transferrin saturation; however, the associations of serum ferritin, inflammation, and liver fat content have been incompletely investigated in children. As magnetic resonance imaging (MRI) is an excellent measure for the degree of liver steatosis, we applied this method herein to clarify the interaction between ferritin and fatty liver in male adolescents. For this study, one hundred fifty male pediatric patients with obesity and who are overweight were included. We studied a subgroup of male patients with (n = 44) and without (n = 18) NAFLD in whom we determined liver fat content, visceral adipose tissue, and subcutaneous adipose tissue extent with a 1.5T MRI (Philips NL). All patients underwent a standardized oral glucose tolerance test. We measured uric acid, triglycerides, HDL-, LDL-, total cholesterol, liver transaminases, high sensitive CRP (hsCRP), interleukin-6, HbA1c, and insulin. In univariate analysis, ferritin was associated with MRI liver fat, visceral adipose tissue content, hsCRP, AST, ALT, and GGT, while transferrin and soluble transferrin receptor were not associated with ferritin. Multivariate analysis identified hsCRP and liver fat content as independent predictors of serum ferritin in the pediatric male patients. Our data indicate that serum ferritin in male adolescents with obesity is mainly determined by liver fat content and inflammation but not by body iron status.

Macrophage Function in the Pathogenesis of Non-alcoholic Fatty Liver Disease: The Mac Attack

Obesity is a prevalent predisposing factor to non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease in the developed world. NAFLD spectrum of disease involves progression from steatosis (NAFL), to steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). Despite clinical and public health significance, current FDA approved therapies for NAFLD are lacking in part due to insufficient understanding of pathogenic mechanisms driving disease progression. The etiology of NAFLD is multifactorial. The induction of both systemic and tissue inflammation consequential of skewed immune cell metabolic state, polarization, tissue recruitment, and activation are central to NAFLD progression. Here, we review the current understanding of the above stated cellular and molecular processes that govern macrophage contribution to NAFLD pathogenesis and how adipose tissue and liver crosstalk modulates macrophage function. Notably, the manipulation of such events may lead to the development of new therapies for NAFLD.

Adipocyte-specific disruption of ATPase copper transporting α in mice accelerates lipoatrophy

AIMS/HYPOTHESIS

ATPase copper transporting α (ATP7A), also known as Menkes disease protein, is a P-type ATPase that transports copper across cell membranes. The critical role of ATP7A-mediated copper homeostasis has been well recognised in various organs, such as the intestine, macrophages and the nervous system. However, the importance of adipocyte ATP7A-mediated copper homeostasis on fat metabolism is not well understood. Here, we sought to reveal the contribution of adipose ATP7A to whole-body fat metabolism in mice.

METHODS

We generated adipocyte-specific Atp7a-knockout (ASKO) mice using the Cre/loxP system, with Cre expression driven by the adiponectin promoter. ASKO mice and littermate control mice were aged on a chow diet or fed with a high-fat diet (HFD); body weight, fat mass, and glucose and insulin metabolism were analysed. Histological analysis, transmission electron microscopy and RNA-sequencing (RNA-Seq) analysis of white adipose tissue (WAT) were used to understand the physiological and molecular changes associated with loss of copper homeostasis in adipocytes.

RESULTS

Significantly increased copper concentrations were observed in adipose tissues of ASKO mice compared with control mice. Aged or HFD-fed ASKO mice manifested a lipoatrophic phenotype characterised by a progressive generalised loss of WAT. Dysfunction of adipose tissues in these ASKO mice was confirmed by decreased levels of both serum leptin and adiponectin and increased levels of triacylglycerol and insulin. Systemic metabolism was also impaired in these mice, as evidenced by a pronounced glucose intolerance, insulin resistance and hepatic steatosis. Moreover, we demonstrate a significant induction of lipolysis and DNA-damage signalling pathways in gonadal WAT from aged and HFD-fed ASKO mice. In vitro studies suggest that copper overload is responsible for increased lipolysis and DNA damage.

CONCLUSIONS/INTERPRETATION

Our results show a previously unappreciated role of adipocyte Atp7a in the regulation of ageing-related metabolic disease and identify new metallophysiologies in whole-body fat metabolism.

DATA AVAILABILITY

The datasets generated during the current study are available in the Genome Sequence Archive in BIG Data Center, Beijing Institute of Genomics (BIG), Chinese Academy of Sciences, under accession number CRA001769 (http://bigd.big.ac.cn/gsa).

Dietary Iron Modulates Glucose and Lipid Homeostasis in Diabetic Mice

Imbalance of iron homeostasis has been involved in clinical courses of metabolic diseases such as type 2 diabetes mellitus, obesity, and nonalcoholic fatty liver, through mechanisms not yet fully elucidated. Herein, we evaluated the effect of dietary iron on the development of diabetic syndromes in genetically obese db/db mice. Mice (aged 7 weeks) were fed with high-iron (HI) diets (1000 mg/kg chow) or low-iron (LI) diets (12 mg/kg) for 9 weeks. HI diets increased hepatic iron threefold and led to fourfold higher mRNA levels of hepcidin. HI also induced a 60% increase in fasting glucose due to insulin resistance, as confirmed by decreased hepatic glycogen deposition eightfold and a 21% decrease of serum adiponectin level. HI-fed mice had lower visceral adipose tissue mass estimated by epididymal and inguinal fat pad, associated with iron accumulation and smaller size of adipocytes. Gene expression analysis of liver showed that HI diet upregulated gluconeogenesis and downregulated lipogenesis. These results suggested that excess dietary iron leads to reduced mass, increased fasting glucose, decreased adiponectin level, and enhancement of insulin resistance, which indicated a multifactorial role of excess iron in the development of diabetes in the setting of obesity.

Influence of endurance and endurance-strength training on mineral status in women with abdominal obesity: a randomized trial

BACKGROUND

Obesity and exercise are associated with disturbances of mineral metabolism, which can lead to physical inefficiency. Our study aimed to compare the influence of endurance and endurance-strength training on mineral status in women with abdominal obesity.

METHODS

Thirty-eight abdominally obese women were randomized into groups A and B and underwent 3 months long training: group A-endurance training and group B-endurance-strength training. Anthropometric and body composition measurements were carried out and the Graded Exercise Test was performed. Blood, urine, and hair samples were collected for mineral content analysis.

RESULTS

Endurance training decreased serum Fe and Zn concentrations as well as hair Zn and Cu content, and increased urine Zn concentration. Endurance-strength training increased serum Mg and Cu concentrations, decreased serum Fe and Zn concentrations, decreased hair Ca and Mg content, and increased urine Ca and Zn concentrations. After training, serum and urine Fe concentration was higher in group A, while urine Ca concentration was higher in group B. A number of correlations was found.

CONCLUSIONS

Both endurance and endurance-strength training have a significant effect on mineral metabolism in obese women; the favorable effects of endurance-strength exercise predominate in iron, magnesium, zinc, and copper balance.

Cross-sectional correlation between hepatic R2* and proton density fat fraction (PDFF) in children with hepatic steatosis

PURPOSE

To determine the relationship between hepatic proton density fat fraction (PDFF) and R2* in vivo.

MATERIALS AND METHODS

In this Health Insurance Portability and Accountability Act (HIPAA)-compliant, Institutional Review Board (IRB)-approved, cross-sectional study, we conducted a secondary analysis of 3T magnetic resonance imaging (MRI) exams performed as part of prospective research studies in children in whom conditions associated with iron overload were excluded clinically. Each exam included low-flip-angle, multiecho magnitude (-M) and complex (-C) based chemical-shift-encoded MRI techniques with spectral modeling of fat to generate hepatic PDFF and R2* parametric maps. For each technique and each patient, regions of interest were placed on the maps in each of the nine Couinaud segments, and composite whole-liver PDFF and R2* values were calculated. Pearson's correlation coefficients between PDFF and R2* were computed for each MRI technique. Correlations were compared using Steiger's test.

RESULTS

In all, 184 children (123 boys, 61 girls) were included in this analysis. PDFF estimated by MRI-M and MRI-C ranged from 1.1-35.4% (9.44 ± 8.76) and 2.1-38.1% (10.1 ± 8.7), respectively. R2* estimated by MRI-M and MRI-C ranged from 32.6-78.7 s-1 (48.4 ± 9.8) and 27.2-71.5 s-1 (42.2 ± 8.6), respectively. There were strong and significant correlations between hepatic PDFF and R2* values estimated by MRI-M (r = 0.874; P < 0.0001) and MRI-C (r = 0.853; P < 0.0001). The correlation coefficients (0.874 vs. 0.853) were not significantly different (P = 0.15).

CONCLUSION

Hepatic PDFF and R2* are strongly correlated with each other in vivo. This relationship was observed using two different MRI techniques.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:418-424.

Low Hepatic Tissue Copper in Pediatric Nonalcoholic Fatty Liver Disease

OBJECTIVE

Animal models and studies in adults have demonstrated that copper restriction increases severity of liver injury in nonalcoholic fatty liver disease (NAFLD). This has not been studied in children. We aimed to determine if lower tissue copper is associated with increased NAFLD severity in children.

METHODS

This was a retrospective study of pediatric patients who had a liver biopsy including a hepatic copper quantitation. The primary outcome compared hepatic copper concentration in NAFLD versus non-NAFLD. Secondary outcomes compared hepatic copper levels against steatosis, fibrosis, lobular inflammation, balloon degeneration, and NAFLD activity score (NAS).

RESULTS

The study analysis included 150 pediatric subjects (102 with NAFLD and 48 non-NAFLD). After adjusting for age, body mass index z score, gamma glutamyl transferase, alanine aminotransferase, and total bilirubin, NAFLD subjects had lower levels of hepatic copper than non-NAFLD (P = 0.005). In addition, tissue copper concentration decreased as steatosis severity increased (P < 0.001). Copper levels were not associated with degree of fibrosis, lobular inflammation, portal inflammation, or balloon degeneration.

CONCLUSIONS

In this cohort of pediatric subjects with NAFLD, we observed decreased tissue copper levels in subjects with NAFLD when compared with non-NAFLD subjects. In addition, tissue copper levels were lower in subjects with nonalcoholic steatohepatitis, a more severe form of the disease, when compared with steatosis alone. Further studies are needed to explore the relationship between copper levels and NAFLD progression.

Fat content, fatty acid pattern and iron content in livers of turkeys with hepatic lipidosis

BACKGROUND

The so-called "hepatic lipidosis" in turkeys is an acute progressive disease associated with a high mortality rate in a very short time. Dead animals show a massive fatty degeneration of the liver. The cause is still unclear. Previous findings suggest that there may be parallels to human non-alcoholic fatty liver disease. The object of the study was to examine the changes in the fat contents, the fatty acid composition and the iron content in livers of animals, which have died from hepatic lipidosis.

METHODS

The conspicuous livers (n = 85) were collected from 20 flocks where the phenomenon of massive increased animal losses accompanied by marked macroscopically visible pathological liver steatosis suddenly occurred. For comparison and as a reference, livers (n = 16) of two healthy flocks were taken. Healthy and diseased flocks were fed identical diets concerning official nutrient recommendations and were operating under standardized, comparable conventional conditions.

RESULTS

Compared to livers of healthy animals, in the livers of turkeys died from hepatic lipidosis there were found massively increased fat levels (130 ± 33.2 vs. 324 ± 101 g/kg dry matter-DM). In all fatty livers, different fatty acids concentrations were present in significantly increased concentrations compared to controls (palmitic acid: 104 g/kg DM, +345%; palmitoleic acid: 18.0 g/kg DM, + 570%; oleic acid: 115 g/kg DM, +437%). Fatty acids concentrations relevant for liver metabolism and inflammation were significantly reduced (arachidonic acid: 2.92 g/kg DM, -66.6%; eicosapentaenoic acid: 0.141 g/kg DM, -78.3%; docosahexaenoic acid: 0.227 g/kg DM, -90.4%). The ratio of certain fatty acids to one another between control and case livers changed analogously to liver diseases in humans (e.g.: C18:0/C16:0 - 0.913 against 0.311; C16:1n7/C16:0 - 0.090 against 0.165; C18:1/C18:0 - 0.938 against 4.03). The iron content in the liver tissue also increased massively (271 ± 51.5 vs 712 ± 214 mg/kg DM).

CONCLUSION

The hepatic lipidosis has a massive impact on the lipid content, the lipid composition and the iron content in the liver. The character of the metabolic disorder includes parallels to the non-alcoholic steatohepatitis in humans.

Clinical implications of understanding the association between oxidative stress and pediatric NAFLD

Oxidative stress is central to the pathogenesis of non-alcoholic steatohepatitis. The reactive oxygen species (ROS) that characterise oxidative stress are generated in several cellular sites and their production is influence by multi-organ interactions. Areas covered: Mitochondrial dysfunction is the main source of ROS in fatty liver and is closely related to endoplasmic reticulum stress. Both are caused by lipotoxicity and together these three factors form a cycle of progressive organelle damage, resulting in sterile inflammation and apoptosis. Adipose tissue inflammation and intestinal dysbiosis provide substrates for ROS formation and trigger immune activation. Obstructive sleep apnea and abnormal divalent metal metabolism may also play a role. Expert commentary: The majority of available high-quality data originates from studies in adults and there are fewer therapeutic trials performed in pediatric cohorts, therefore conclusions are generalised to children. Establishing the role of organelle interactions, and its relationship with oxidative stress in steatohepatitis, is a rapidly evolving area of research.

Early High-Fat Feeding Induces Alteration of Trace Element Content in Tissues of Juvenile Male Wistar Rats

The primary objective of the current study was to assess the influence of early high-fat feeding on tissue trace element content in young male Wistar rats. Twenty weanling male Wistar rats were divided into two groups fed standard (STD) or high-fat diet (HFD) containing 10 and 31.6 % of total calories from fat, respectively, for 1 month. Serum lipid spectrum, apolipoproteins, glucose, insulin, adiponectin, and leptin levels were assessed. The level of trace elements was estimated using inductively coupled plasma mass spectrometry. High-fat feeding significantly increased epidydimal (EDAT) and retroperitoneal adipose tissue (RPAT), as well as total adipose tissue mass by 34, 103, and 59 %, respectively. Serum leptin levels in HFD animals were twofold higher than those in the control rats. No significant difference in serum lipid spectrum, apolipoproteins, glucose, adiponectin, and insulin was detected between the groups. HFD significantly altered tissue trace element content. In particular, HFD-fed animals were characterized by significantly lower levels of Cu, I, Mn, Se, and Zn in the liver; Cr, V, Co, Cu, Fe, and I content of EDAT; Co, Cu, I, Cr, V, Fe, and Zn concentration in RPAT samples. At the same time, only serum Cu was significantly depressed in HFD-fed animals as compared to the control ones. Hair Co, Mn, Si, and V levels were significantly increased in comparison to the control values, whereas Se and I content was decreased. HFD feeding induced excessive adiposity and altered tissue trace element content in rats without insulin resistance, adiponectin deficiency, and proatherogenic state. Hypothetically, trace element disbalance may precede obesity-associated metabolic disturbances.

In vivo bioluminescence imaging reveals copper deficiency in a murine model of nonalcoholic fatty liver disease

Copper is a required metal nutrient for life, but global or local alterations in its homeostasis are linked to diseases spanning genetic and metabolic disorders to cancer and neurodegeneration. Technologies that enable longitudinal in vivo monitoring of dynamic copper pools can help meet the need to study the complex interplay between copper status, health, and disease in the same living organism over time. Here, we present the synthesis, characterization, and in vivo imaging applications of Copper-Caged Luciferin-1 (CCL-1), a bioluminescent reporter for tissue-specific copper visualization in living animals. CCL-1 uses a selective copper(I)-dependent oxidative cleavage reaction to release d-luciferin for subsequent bioluminescent reaction with firefly luciferase. The probe can detect physiological changes in labile Cu+ levels in live cells and mice under situations of copper deficiency or overload. Application of CCL-1 to mice with liver-specific luciferase expression in a diet-induced model of nonalcoholic fatty liver disease reveals onset of hepatic copper deficiency and altered expression levels of central copper trafficking proteins that accompany symptoms of glucose intolerance and weight gain. The data connect copper dysregulation to metabolic liver disease and provide a starting point for expanding the toolbox of reactivity-based chemical reporters for cell- and tissue-specific in vivo imaging.

Pediatric non-alcoholic fatty liver disease: Recent solutions, unresolved issues, and future research directions

Non-alcoholic fatty liver disease (NAFLD) in children is becoming a major health concern. A “multiple-hit” pathogenetic model has been suggested to explain the progressive liver damage that occurs among children with NAFLD. In addition to the accumulation of fat in the liver, insulin resistance (IR) and oxidative stress due to genetic/epigenetic background, unfavorable lifestyles, gut microbiota and gut-liver axis dysfunction, and perturbations of trace element homeostasis have been shown to be critical for disease progression and the development of more severe inflammatory and fibrotic stages [non-alcoholic steatohepatitis (NASH)]. Simple clinical and laboratory parameters, such as age, history, anthropometrical data (BMI and waist circumference percentiles), blood pressure, surrogate clinical markers of IR (acanthosis nigricans), abdominal ultrasounds, and serum transaminases, lipids and glucose/insulin profiles, allow a clinician to identify children with obesity and obesity-related conditions, including NAFLD and cardiovascular and metabolic risks. A liver biopsy (the “imperfect” gold standard) is required for a definitive NAFLD/NASH diagnosis, particularly to exclude other treatable conditions or when advanced liver disease is expected on clinical and laboratory grounds and preferably prior to any controlled trial of pharmacological/surgical treatments. However, a biopsy clearly cannot represent a screening procedure. Advancements in diagnostic serum and imaging tools, especially for the non-invasive differentiation between NAFLD and NASH, have shown promising results, e.g., magnetic resonance elastography. Weight loss and physical activity should be the first option of intervention. Effective pharmacological treatments are still under development; however, drugs targeting IR, oxidative stress, proinflammatory pathways, dyslipidemia, gut microbiota and gut liver axis dysfunction are an option for patients who are unable to comply with the recommended lifestyle changes. When morbid obesity prevails, bariatric surgery should be considered.

Targeting endoplasmic reticulum stress in liver disease

INTRODUCTION

The accumulation of unfolded protein in the endoplasmic reticulum (ER) initiates an unfolded protein response (UPR) via three signal transduction cascades, which involve protein kinase RNA-like ER kinase (PERK), inositol requiring enzyme-1α (IRE1α) and activating transcription factor-6α (ATF6α). An ER stress response is observed in nearly all physiologies related to acute and chronic liver disease and therapeutic targeting of the mechanisms implicated in UPR signaling have attracted considerable attention.

AREAS COVERED

This review focuses on the correlation between ER stress and liver disease and the possible targets which may drive the potential for novel therapeutic intervention. Expert Commentary: We describe pathways which are involved in UPR signaling and their potential correlation with various liver diseases and underlying mechanisms which may present opportunities for novel therapeutic strategies are discussed.

Study of Serum Hepcidin as a Potential Mediator of the Disrupted Iron Metabolism in Obese Adolescents

BACKGROUND & AIMS

The prevalence of obesity continues to rise in both developed and developing nations. An association between iron status and obesity has been described in children and adults. We aimed to study the relation between serum hepcidin level and both iron as well as high sensitive CRP status in obese adolescents.

MATERIALS & METHODS

This work was conducted on 80 adolescents aging 12-14 years old, divided into two equal groups; obese and non-obese. Anthropometric measurements, determination of haemoglobin, serum iron, total iron binding capacity (TIBC), transferrin saturation, serum ferritin, soluble serum transferrin receptor (sTfR), high sensitive CRP (hs -CRP) and serum hepcidin were performed.

RESULTS

Obese adolescents showed significantly lower levels of haemoglobin, serum iron, serum ferritin and transferrin saturation. Significant higher diastolic blood pressure, higher mean TIBC, sTfR, serum hepcidin and hs -CRP were also found. Serum hepcidin level correlated positively with BMI and hs- CRP, but negatively with iron level in obese group.

CONCLUSION

These data suggest that hepcidin is an important modulator of anemia in obese patients. Obesity can be considered as a low grade inflammatory state, that stimulates the production of inflammatory markers such as CRP which can up-regulate hepcidin synthesis.