Both hepatic and body iron stores are increased in dysmetabolic iron overload syndrome. A case-control study

The Cellular Stability Hypothesis: Evidence of Ferroptosis and Accelerated Aging-Associated Diseases as Newly Identified Nutritional Pentadecanoic Acid (C15:0) Deficiency Syndrome

Ferroptosis is a newly discovered form of cell death caused by the peroxidation of fragile fatty acids in cell membranes, which combines with iron to increase reactive oxygen species and disable mitochondria. Ferroptosis has been linked to aging-related conditions, including type 2 diabetes, cardiovascular disease, and nonalcoholic fatty liver disease (NAFLD). Pentadecanoic acid (C15:0), an odd-chain saturated fat, is an essential fatty acid with the primary roles of stabilizing cell membranes and repairing mitochondrial function. By doing so, C15:0 reverses the underpinnings of ferroptosis. Under the proposed "Cellular Stability Hypothesis", evidence is provided to show that cell membranes optimally need >0.4% to 0.64% C15:0 to support long-term health and longevity. A pathophysiology of a newly identified nutritional C15:0 deficiency syndrome ("Cellular Fragility Syndrome") is provided that demonstrates how C15:0 deficiencies (≤0.2% total circulating fatty acids) can increase susceptibilities to ferroptosis, dysmetabolic iron overload syndrome, type 2 diabetes, cardiovascular disease, and NAFLD. Further, evidence is provided that C15:0 supplementation can reverse the described C15:0 deficiency syndrome, including the key components of ferroptosis. Given the declining dietary intake of C15:0, especially among younger generations, there is a need for extensive studies to understand the potential breadth of Cellular Fragility Syndrome across populations.

Association of Non-Invasive Markers with Significant Fibrosis in Patients with Nonalcoholic Fatty Liver Disease: A Cross-Sectional Study

Purpose

The identification of significant fibrosis is critical for predicting the prognosis of non-alcoholic fatty liver disease (NAFLD). This study aimed to compare the predictive value of chitinase-3-like protein 1 (CHl3L1) and other non-invasive biomarkers, as well as to establish a novel non-invasive diagnostic model for assessing the risk of significant fibrosis in NAFLD.

Patients and Methods

A total of 71 patients with confirmed NAFLD based on liver biopsy were included in this study. Serum CHI3L1 levels and other non-invasive fibrosis assessment measures were determined. The aspartate aminotransferase-to-platelet ratio index (APRI) and Fibrosis-4 Index (FIB-4) were calculated to assess the diagnostic superiority of serum CHI3L1 compared to other non-invasive fibrosis assessment measures. Multivariate logistic regression analysis was conducted to identify relevant variables for constructing a diagnostic model. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic accuracy of each index, including the area under ROC curve (AUC), sensitivity, and specificity. A nomogram was established based on the logistic regression model.

Results

Serum CHI3LI levels were found to be higher in NAFLD patients with significant fibrosis compared to those without significant fibrosis. Multivariate logistic regression analysis revealed that aspartate aminotransferase (AST), type IV collagen (IV-C), CHI3L1, and liver stiffness measurement (LSM) were identified as potential independent risk factors associated with significant fibrosis in patients. The AUC of CHI3L1 for diagnosing significant liver fibrosis was 0.716 (0.596,0.836), with the optimal cut-off point of 125.315. The nomogram incorporating CHI3LI, AST, IV-C, and LSM further improved the potential predictive value, with an AUC for diagnosing significant fibrosis of 0.864 (0.766,0.962). This was superior to IV-C, CHI3L1, LSM, and APRI (all p < 0.05).

Conclusion

The diagnostic model constructed by CHI3L1 combined with the existing non-invasive markers AST, IV-C, and LSM can help assess the risk of significant liver fibrosis in NAFLD.

Consensus Statement on the definition and classification of metabolic hyperferritinaemia

Hyperferritinaemia is a common laboratory finding that is often associated with metabolic dysfunction and fatty liver. Metabolic hyperferritinaemia reflects alterations in iron metabolism that facilitate iron accumulation in the body and is associated with an increased risk of cardiometabolic and liver diseases. Genetic variants that modulate iron homeostasis and tissue levels of iron are the main determinants of serum levels of ferritin in individuals with metabolic dysfunction, raising the hypothesis that iron accumulation might be implicated in the pathogenesis of insulin resistance and the related organ damage. However, validated criteria for the non-invasive diagnosis of metabolic hyperferritinaemia and the staging of iron overload are still lacking, and there is no clear evidence of a benefit for iron depletion therapy. Here, we provide an overview of the literature on the relationship between hyperferritinaemia and iron accumulation in individuals with metabolic dysfunction, and on the associated clinical outcomes. We propose an updated definition and a provisional staging system for metabolic hyperferritinaemia, which has been agreed on by a multidisciplinary global panel of expert researchers. The goal is to foster studies into the epidemiology, genetics, pathophysiology, clinical relevance and treatment of metabolic hyperferritinaemia, for which we provide suggestions on the main unmet needs, optimal design and clinically relevant outcomes.

Dysmetabolic Iron Overload Syndrome: Going beyond the Traditional Risk Factors Associated with Metabolic Syndrome

Dysmetabolic iron overload syndrome (DIOS) corresponds to the increase in iron stores associated with components of metabolic syndrome (MtS) and in the absence of an identifiable cause of iron excess. The objective of this work was to review the main aspects of DIOS. PUBMED and EMBASE were consulted, and PRISMA guidelines were followed. DIOS is usually asymptomatic and can be diagnosed by investigating MtS and steatosis. About 50% of the patients present altered hepatic biochemical tests (increased levels of γ-glutamyl transpeptidase itself or associated with increased levels of alanine aminotransferase). The liver may present parenchymal and mesenchymal iron overload, but the excess of iron is commonly mild. Steatosis or steatohepatitis is observed in half of the patients. Fibrosis is observed in about 15% of patients. Hyperferritinemia may damage the myocardium, liver, and several other tissues, increasing morbidity and mortality. Furthermore, DIOS is closely related to oxidative stress, which is closely associated with several pathological conditions such as inflammatory diseases, hypertension, diabetes, heart failure, and cancer. DIOS is becoming a relevant finding in the general population and can be associated with high morbidity/mortality. For these reasons, investigation of this condition could be an additional requirement for the early prevention of cardiovascular diseases.

Albuminuria Is Associated with Hepatic Iron Load in Patients with Non-Alcoholic Fatty Liver Disease and Metabolic Syndrome

Background: Increased albuminuria is associated with increased serum ferritin, insulin resistance, and non-alcoholic fatty liver disease (NAFLD). Liver iron accumulation is also related to hyperferritinemia, insulin resistance, and NAFLD; however, there is no evidence on its relationship with albuminuria. Aims: To assess the relationship between hepatic iron load and urine albumin-to-creatinine ratio (UACR) in patients with metabolic syndrome (MetS) and NAFLD. Methods: In total, 75 MetS and NAFLD patients (aged 40–60 years, BMI 27–40 kg/m²) were selected from a cohort according to available data on hepatic iron load (HepFe) by magnetic resonance imaging (MRI). Subjects underwent anthropometric measurements, biochemistry testing, and liver MRI. Increased albuminuria was defined by UACR. Results: UACR correlated with NAFLD, HepFe, triglycerides, serum ferritin, fasting insulin, insulin resistance (calculated using the homeostatic model assessment for insulin resistance—HOMA-IR- formula), and platelets (p < 0.05). Multiple regression analysis adjusted for gender, age, eGFR, HbA1c, T2DM, and stages of NAFLD, found that HepFe (p = 0.02), serum ferritin (p = 0.04), fasting insulin (p = 0.049), and platelets (p = 0.009) were associated with UACR (R² = 0.370; p = 0.007). UACR, liver fat accumulation, serum ferritin, and HOMA-IR increased across stages of HepFe (p < 0.05). Patients with severe NAFLD presented higher HepFe, fasting insulin, HOMA-IR, and systolic blood pressure as compared to patients in NAFLD stage 1 (p < 0.05). Conclusion: Hepatic iron load, serum ferritin, fasting insulin, and platelets were independently associated with albuminuria. In the context of MetS, increased stages of NAFLD presented higher levels of HepFe. Higher levels of HepFe were accompanied by increased serum ferritin, insulin resistance, and UACR. The association between iron accumulation, MetS, and NAFLD may represent a risk factor for the development of increased albuminuria.

Prevalence and Factors Associated with Hepatic Iron Overload in Obese Individuals Undergoing Bariatric Surgery: a Cross-Sectional Study

BACKGROUND

Slight to moderate hepatic iron overload (HIO) can be found in cases of liver disease, including non-alcoholic fatty liver disease (NAFLD), but the mechanism is not completely understood, as well as its relationship with obesity.

OBJECTIVE

To determine the prevalence of HIO assessed through histopathological examination in obese individuals undergoing bariatric surgery and to identify correlations between this condition and demographic, anthropometric, clinical, laboratory, and NAFLD-related aspects.

METHODS

This is a cross-sectional study which enrolled individuals undergoing bariatric surgery from January 2018 to February 2019 at a tertiary university hospital. NAFLD and HIO were assessed through histological examination.

RESULTS

Of 125 individuals, 87.2% were female and the average age was 38.8 ± 9.2 years. The average BMI was 37.2 ± 3.1 kg/m². NAFLD was present in 66.4% and HIO in 17.6%, with 63.6% of patients with overload classified as mild (grade I) and 22.7% moderate (grade II). HIO was significantly more frequent in males (p = 0.003) and was significantly associated with higher levels of glucose (92.1 ± 28.4 vs. 80.7 ± 39.6; p = 0.02), ferritin (385.5 ± 290.9 vs. 131.6 ± 99.7; p < 0.0001), serum iron (82.4 ± 35.7 vs. 66.6 ± 25.1; p = 0.03), glutamic-oxaloacetic transaminase (27.3 ± 19.5 vs. 20.6 ± 8.8; p = 0.02), and glutamic-pyruvic transaminase (37.6 ± 36.4 vs. 24.6 ± 16.3; p = 0.01). Multivariate analysis showed that HIO intensity was significant and independently associated with ferritin levels (R = 0.19; p = 0.01), serum iron (R = 0.25; p < 0.0001), blood glucose (R = 0.16; p = 0.001), and total cholesterol (R = - 0.17; p < 0.0001).

CONCLUSION

In obese individuals, HIO presented a high prevalence and was associated with higher levels of ferritin, serum iron, glucose, and transaminases; lower levels of total cholesterol; and male gender.

Liver iron concentration in dysmetabolic hyperferritinemia: Results from a prospective cohort of 276 patients

INTRODUCTION AND OBJECTIVES

We aimed to study the liver iron concentration in patients referred for hyperferritinemia to six hospitals in the Basque Country and to determine if there were differences between patients with or without metabolic syndrome.

PATIENTS AND METHODS

Metabolic syndrome was defined by accepted criteria. Liver iron concentration was determined by magnetic resonance imaging.

RESULTS

We obtained the data needed to diagnose metabolic syndrome in 276 patients; a total of 135 patients (49%), 115/240 men (48%), and 20/36 women (55.6%) presented metabolic syndrome. In all 276 patients, an MRI for the determination of liver iron concentration (mean±SD) was performed. The mean liver iron concentration was 30.83±19.38 for women with metabolic syndrome, 38.84±25.50 for men with metabolic syndrome, and 37.66±24.79 (CI 95%; 33.44-41.88) for the whole metabolic syndrome group. In 141 patients (51%), metabolic syndrome was not diagnosed: 125/240 were men (52%) and 16/36 were women (44.4%). The mean liver iron concentration was 34.88±16.18 for women without metabolic syndrome, 44.48±38.16 for men without metabolic syndrome, and 43.39±36.43 (CI 95%, 37.32-49.46) for the whole non-metabolic syndrome group. Comparison of the mean liver iron concentration from both groups (metabolic syndrome vs non-metabolic syndrome) revealed no significant differences (p=0.12).

CONCLUSIONS

Patients with hyperferritinemia and metabolic syndrome presented a mildly increased mean liver iron concentration that was not significantly different to that of patients with hyperferritinemia and non-metabolic syndrome.

Increased adiposity by feeding growing rats a high-fat diet results in iron decompartmentalisation

The present study reports the effects of a high-fat (HF) diet of over 8 weeks on the Fe status of growing rats. Tissue Fe levels were analysed by atomic absorption spectrophotometry, and whole-body adiposity was measured by dual-energy X-ray absorptiometry. Histopathology and morphometry of adipose tissue were performed. Liver homogenates were used for measuring ferroportin-1 protein levels by immunoblotting, and transcript levels were used for Fe genes measured by real-time PCR. Tissue Fe pools were fit to a compartmental biokinetic model in which Fe was assessed using fourteen compartments and twenty-seven transfer constants (kj,i from tissue 'i' to tissue 'j') adapted from the International Commission on Radiological Protection (ICRP) 69. Ten kj,i were calculated from the experimental data using non-linear regression, and seventeen were estimated by allometry according to the formula ${k_{i,j}} = a \times {M^b}$. Validation of the model was carried out by comparing predicted and analysed Fe pool sizes in erythrocytes, the liver and the spleen. Body adiposity was negatively associated with serum Fe levels and positively associated with liver Fe stores. An inferred increase in Fe transfer from bone marrow to the liver paralleled higher hepatic Fe concentrations and ferritin heavy-chain mRNA levels in the HF diet-fed animals, suggesting that liver Fe accumulation occurred at least in part due to a favoured liver erythrocyte uptake. If this feeding condition was to be prolonged, impaired Fe decompartmentalisation may occur, ultimately resulting in dysmetabolic Fe overload.

Dysmetabolic iron overload syndrome (DIOS)

Dysmetabolic iron overload syndrome (DIOS) corresponds to mild increase in both liver and body iron stores associated with various components of metabolic syndrome in the absence of any identifiable cause of iron excess. It is characterized by hyperferritinemia with normal or moderately increased transferrin saturation, one or several metabolic abnormalities (increased body mass index with android distribution of fat, elevated blood pressure, dyslipidaemia, abnormal glucose metabolism, steatohepatitis), and mild hepatic iron excess at magnetic resonance imaging or liver biopsy. Alteration of iron metabolism in DIOS likely results from a multifactorial and dynamic process triggered by an excessively rich diet, facilitated by environmental and genetic cofactors and implying a cross-talk between the liver and visceral adipose tissue. Phlebotomy therapy cannot be currently considered as a valuable option in DIOS patients. Sustained modification of diet and life-style habits remains the first therapeutic intervention in these patients together with drug control of increased blood pressure, abnormal blood glucose and dyslipidaemia when necessary.

Metabolic and hepatic effects of bloodletting in dysmetabolic iron overload syndrome: A randomized controlled study in 274 patients

Dysmetabolic iron overload syndrome (DIOS) is a common cause of hyperferritinemia, accounting for a mild increase of iron stores in insulin-resistant subjects. Iron removal could improve insulin sensitivity. We performed a prospective, randomized, controlled trial (NCT01015525) in nondiabetic DIOS patients with hepatic iron >50 μmol/g at magnetic resonance imaging to compare the metabolic and hepatic outcomes of 1-year maintenance of serum ferritin levels <50 μg/L by bloodletting associated with lifestyle and diet advice (LFDA) to those of LFDA only. Patients were randomly assigned (1:1) with stratification by center (n = 8) and hyperglycemia (>5.6 mmol/L). Sample size was calculated to provide 90% power and a difference in fasting glycemia of 0.25 mmol/L. Analysis was done in an intention-to-treat population. In 2010-2014, 146 patients were randomly assigned to receive venesections with LFDA and 128 to LFDA only. At the end of the study, comparison of iron-depleted patients and controls showed ferritin levels 71 ± 48 μg/L after removal of 4.9 ± 1.6 L of blood versus 733 ± 277 μg/L (P < 0.0001), glycemia 5.44 ± 0.7 versus 5.49 ± 0.7 mmol/L (P = 0.57), body weight +0.5 ± 4.3% versus -0.6 ± 3.3% (P = 0.03), homeostasis model of assessment of insulin resistance 3.39 versus 2.40 (P = 0.002), alanine aminotransaminase 33 ± 22 versus 37 ± 21 IU/L (P = 0.10), aspartate aminotransaminase 27 ± 13 versus 27 ± 10 IU/L (P = 0.81), gamma-glutamyl transferase 54 ± 138 versus 49 ± 35 IU/L (P = 0.72), Fatty Liver Index 58.9 ± 24.6 versus 61.2 ± 22.9 (P = 0.37), and Fibrosis-4 score 1.5 ± 0.6 versus 1.30 ± 0.6 (P = 0.51). Fatigue occurred in 25.3% of venesected patients versus 2.3% of controls (P < 0.0001). In the subgroup of patients who lost weight, glycemia, homeostasis model of assessment of insulin resistance, serum ferritin, lipid profile, and liver function tests improved irrespective of bloodletting.

CONCLUSION

In DIOS patients, iron depletion by bloodletting does not improve metabolic and hepatic features, is associated with weight gain, and is not as well tolerated as expected; sustained modification of diet and lifestyle habits remains the first therapeutic intervention in DIOS. (Hepatology 2017;65:465-474).