Increased iron in HCV infection: collateral damage or antiviral defense?

L-shaped association between dietary iron intake and HPV infection: a cross-sectional analysis based on national health and nutrition examination survey 2005-2016

Background

Human Papillomavirus (HPV) infection is a ubiquitous sexually transmitted infection globally, frequently associated with sexual behaviors characterized by increased frequency and multiple partnerships. The relationship between varying levels of dietary iron intake and the occurrence of Human Papillomavirus (HPV) infection remains an unresolved question in the scientific community. The objective of our study was to investigate the potential relationship between the consumption of dietary iron and HPV infection.

Methods

Our investigation drew upon comprehensive datasets from 7,819 participants enrolled in the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2016. Employing a cross-sectional analytical framework, we delved into the potential correlation between dietary iron consumption and Human Papillomavirus infection. To statistically assess this relationship, we utilized weighted multivariate logistic regression models. Additionally, we implemented smooth curve fitting and threshold effect analysis, to delineate the complex, nonlinear association between iron intake and HPV infection. Furthermore, we conducted subgroup analyses.

Results

After adjusting for multiple confounding variables, our results demonstrated a statistically significant inverse association between iron intake and HPV infection (OR = 0.988, 95% CI: 0.979-0.998, p = 0.018). It's worth noting that, in comparison to individuals in the quartile with the lowest iron intake, those in the highest quartile exhibited a 23.2% reduction in the odds of HPV infection for each incremental unit of iron intake (OR = 0.768, 95% CI: 0.634 to 0.930, p = 0.009). A refined analysis employing smoothing curve fitting techniques unveiled an L-shaped correlation, delineating a specific relationship between dietary iron intake and the incidence rate of Human Papillomavirus infection. When iron intake was <16.99 mg, a higher incidence of HPV infection was associated with lower levels of iron intake. (OR = 0.968, 95% CI: 0.956-0.980, p < 0.001).

Conclusion

The presence of an L-shaped association between iron intake and HPV infection underscores and emphasizes the possible beneficial effect of sufficient iron intake in reducing the likelihood of HPV infection.

Dynamic Changes in Brain Iron Metabolism in Neonatal Rats after Hypoxia-Ischemia

OBJECTIVES

The pathogenesis of hypoxic-ischemic white matter injury (WMI) in premature infants is still unclear, and the imbalance of cerebral iron metabolism may play an important role. Our study set out to investigate the changes in iron distribution, iron content and malondialdehyde (MDA) in disparate brain regions (parietal cortex, corpus callosum, hippocampus) within 84 days after hypoxia-ischemia (HI) in neonatal rats and to clarify the role of iron metabolism in WMI.

MATERIALS AND METHODS

We adopted a rat model of hypoxic-ischemic WMI. Alterations in iron metabolism were detected by iron staining and iron assay kits, and the degree of brain injury was determined by MDA assays.

RESULTS

Our results showed that different degrees of brain iron deposition occurred within 28 days after HI, and iron staining was the most obvious 3 days after HI. The iron content increased remarkably at 1-7 d after HI in the mixed tissues, especially at 3 d after HI. While the iron content in the parietal cortex and corpus callosum elevated obviously 14 days after HI. And the change trend of MDA was almost consistent with that of the iron content.

CONCLUSIONS

Our findings revealed that brain iron metabolism changed dynamically in 3-day-old neonatal rats suffering from HI, which may cause lipid peroxidation damage to brain tissues. This process may be one of the pathogeneses of hypoxic-ischemic WMI.

Coinfection with HIV-1 alleviates iron accumulation in patients with chronic hepatitis C virus infection

Most chronically-infected hepatitis C virus (HCV) patients have increased levels of iron in the liver. Iron overload reduces sustained responses to antiviral therapy, leading to more rapid progression to liver cirrhosis and the development of hepatocellular carcinoma. However, it is still unclear how HIV-1 infection affects iron status in patients chronically infected with HCV. The present study recruited 227 patients from a village in central China. These patients were either monoinfected with HCV (n = 129) or coinfected with HCV/HIV-1 (n = 98). Healthy controls (n = 84) were also recruited from the same village. Indicators of iron status, such as serum levels of iron, ferritin, and transferrin, total iron-binding capacity (TIBC), transferrin saturation (Tfs), and hepcidin, were analyzed and compared across the three groups. The results showed that serum levels of iron (p = 0.001) and ferritin (p = 0.009) and the Tfs (p = 0.002) were significantly higher in HCV-monoinfected patients than in the healthy controls; however, there were no differences in iron levels and Tfs between HCV/HIV-1 coinfected patients and healthy controls. Additionally, although serum hepcidin levels in HCV-monoinfected and HCV/HIV-1-coinfected patients were lower (p<0.001) than those in health controls, the levels in coinfected patients were higher (p = 0.025) than those in HCV-monoinfected patients. Serum iron and ferritin levels in HCV-monoinfected patients were positively correlated with serum ALT/AST. Serum transferrin levels were negatively correlated with ALT/AST levels. The levels of iron in the serum of coinfected patients with a CD4+T-cell count <500/µl were lower than those in patients with a CD4+T-cell count ≥500/µl, whereas serum hepcidin levels showed the opposite trend. Taken together, these results suggest that coinfection with HIV-1 alleviates iron accumulation caused by chronic HCV infection. Our study indicated that determining the status of serum iron and other iron-associated parameters will be helpful to understand the complexity of alternations in iron distribution in HCV/HIV-1-coinfected patients.

Hepatitis C virus infection causes iron deficiency in Huh7.5.1 cells

Patients with chronic hepatitis C virus (HCV) infection frequently develop systemic iron overload, which exacerbates morbidity. Nevertheless, iron inhibits HCV replication in cell culture models and thereby exerts antiviral activity. We hypothesized that the cellular iron status is crucial for the establishment of HCV infection. We show that HCV infection of permissive Huh7.5.1 hepatoma cells promotes an iron deficient phenotype. Thus, HCV leads to increased iron regulatory protein (IRP) activity, accumulation of IRP2 and suppression of transferrin receptor 1 (TfR1) and divalent metal transporter 1 (DMT1) in the host. These data suggest that HCV regulates cellular iron levels to bypass iron-mediated inhibition in viral replication.

Inhibition of hepcidin transcription by growth factors

The hepatic peptide hormone hepcidin controls the duodenal absorption of iron, its storage, and its systemic distribution. Hepcidin production is often insufficient in chronic hepatitis C and alcoholic liver disease, leading to hyperabsorption of iron and its accumulation in the liver. Hepatocyte growth factor (HGF) and epidermal growth factor (EGF) mediate hepatic regeneration after liver injury. We examined the effect of these growth factors on hepcidin synthesis by hepatocytes. HGF and EGF treatment of primary mouse hepatocytes, as well as EGF administration in mice, suppressed hepcidin messenger RNA (mRNA) synthesis. The suppression of hepcidin by these growth factors was transcriptional, and was mediated by a direct effect of HGF and EGF on the bone morphogenetic protein (BMP) pathway regulating hepcidin synthesis. We further show that growth factors interfered with nuclear localization of activated sons of mothers against decapentaplegic (Smad) and increased the nuclear pool of the BMP transcriptional corepressor TG-interacting factor (TGIF). In a kinase screen with small-molecule kinase inhibitors, inhibitors in the PI3 kinase pathway and in the mitogen-activated ERK kinase/extracellular signal-regulated kinase (MEK/ERK) pathway prevented HGF suppression of hepcidin in primary mouse hepatocytes.

CONCLUSION

HGF and EGF suppress hepatic hepcidin synthesis, in part through PI3 kinase MEK/ERK kinase pathways which may be modulating the nuclear localization of BMP pathway transcriptional regulators including activated Smads1/5/8 and the corepressor TGIF. EGF, HGF, and possibly other growth factors that activate similar pathways may contribute to hepcidin suppression in chronic liver diseases, promote iron accumulation in the liver, and exacerbate the destructive disease processes.