Bone marrow macrophage iron grade and survival of HIV-seropositive patients

Iron status among HIV-infected adults during the first year of antiretroviral therapy in Tanzania

BACKGROUND

The influence of inflammation on iron status among people living with HIV (PLWHIV) has not been well explored. We evaluated the trajectory of iron status among PLWHIV during the first year of highly active antiretroviral therapy (HAART), compared alternative approaches for inflammation correction, and assessed the associations of iron status with HIV-1 viral load and anthropometric outcomes.

METHODS

We conducted a secondary analysis of data from a randomized trial among 400 adults initiating HAART in Tanzania. Ferritin and C-reactive protein (CRP) were measured at baseline, 1, 6 or 12 months. Ferritin was considered in four ways: unadjusted, and adjusted for inflammation using higher cut-off (HC), Thurnham-corrected (TC) and regression-corrected (RC) approaches. For unadjusted, TC and RC ferritin, iron deficiency (ID) was defined using ferritin < 15 μg/L and elevated iron status was defined using ferritin > 150 μg/L among females and > 200 μg/L among males. For HC ferritin, elevated iron status was defined based on serum ferritin > 500 μg/L, while ID was defined using ferritin < 70 μg/L in the presence of inflammation and < 15 μg/L in the absence of inflammation. Regression models evaluated the trajectory of ferritin concentration across categories of baseline characteristics, and assessed the association of iron status with viral and anthropometric outcomes.

RESULTS

The prevalence of iron deficiency at HAART initiation was 9% for unadjusted, 17% for HC, 12% for TC and 22% for RC ferritin. The prevalence of elevated iron status was 42% for unadjusted, 18% for HC, 31% for TC, and 15% for RC ferritin. The prevalence of iron deficiency for all three methods increased during the first year of HAART, while the prevalence of elevated iron status decreased. Baseline elevated iron status defined using HC ferritin was associated with a greater risk of HIV-1 viral load > 1000 copies/mL [relative risk (RR) = 4.29, 95% CI: 1.38-13.3] and incidence of being underweight [body mass index (BMI) < 18.5 kg/m2 , hazard ratio (HR) = 3.65, 95% confidence interval (CI): 1.38-9.67]. Neither baseline-elevated iron status defined using TC or RC ferritin nor baseline iron deficiency defined using any of the three methods was associated with HIV-1 viral load or anthropometric outcomes.

CONCLUSIONS

Whether and how inflammation correction is done influences findings of studies of iron status among PLWHIV.

Asymptomatic Human Immunodeficiency Virus-1 Infection with High CD4+ T Cell Count Does Not Alter Iron Metabolism or Hepcidin Levels: The Pilot Study

INTRODUCTION

The purpose of the study was to assess hepcidin levels and iron metabolism in otherwise healthy human immunodeficiency virus-1 (HIV-1)-infected males and the influence of antiretroviral therapy on hepcidin production, as data in this group are scarce.

METHODS

A total of 89 HIV-1-infected males, 42 on effective antiretroviral therapy (ART)-group A, 47 treatment-naïve-group B, and 27 healthy controls-group C, were enrolled. Erythrocytes parameters, iron metabolism parameters, hepcidin, highly sensitive C-reactive protein (hsCRP), interleukin 6 (IL-6), and soluble transferrin receptor (sTfR) levels were assessed. Conditions related to inflammatory activity, systemic metabolic diseases and iron supplementation were exclusion criteria. Convenience sampling was used.

RESULTS

Median age in HIV-1 group was 33 years, and 27 years in the control group. Median CD4⁺ T-cell count was 724 cells/μl in group A, and 488 cells/μl in group B (p = 0.0000). Nadir CD4⁺ T-cell count was 397 cells/μl in group A and 475 cells/μl in group B (p = 0.0001). Median value of HIV-1 viral load (VL) in group B was 16 900 copies/mL. The hepcidin value was lower in group A than in groups B (p = 0.0008) or C (p = 0.0004), without differences between groups B and C. The hepcidin value correlated with ferritin in groups A (r² = 0.16; p = 0.008) and B (r² = 0.39; p = 0.000), but not in group C (r² = 0.11; p = 0.09). In group A, the hepcidin value correlated with current CD4⁺ count (r = 0.48, p = 0.0012), but there was no correlation in group B. There were no correlations of hepcidin values with CD4⁺ T cell nadir in group A (p = 0.371) or in group B (p = 0.477); ART period (p = 0.614); VL in group B (p = 0.71). No abnormalities of iron metabolism, hsCRP, IL-6, or sTfR were noted.

CONCLUSIONS

Asymptomatic HIV-1 infection does not cause clinically important iron metabolism alterations or increased hepcidin production. Hepcidin values decrease on effective antiretroviral therapy.

Host and Bacterial Iron Homeostasis, an Underexplored Area in Tuberculosis Biomarker Research

Mycobacterium tuberculosis (Mtb) "a human adapted pathogen" has found multiple ways to manipulate the host immune response during infection. The human immune response to Mtb infection is a highly complex cascade of reactions, with macrophages as preferred intracellular location. Interaction with the host through infection gives rise to expression of specific gene products for survival and multiplication within the host. The signals that the pathogens encounter during infection cause them to selectively express genes in response to signals. One strategy to identify Mtb antigens with diagnostic potential is to identify genes that are specifically induced during infection or in specific disease stages. The shortcomings of current immunodiagnostics include the failure to detect progression from latent infection to active tuberculosis disease, and the inability to monitor treatment efficacy. This highlights the need for new tuberculosis biomarkers. These biomarkers should be highly sensitive and specific diagnosing TB infection, specifically distinguishing between latent infection and active disease. The regulation of iron levels by the host plays a crucial role in the susceptibility and outcome of Mtb infection. Of interest are the siderophore biosynthetic genes, encoded by the mbt-1 and mbt-2 loci and the SUF (mobilization of sulphur) operon (sufR-sufB-sufD-sufC-csd-nifU-sufT), which encodes the primary iron-sulphur cluster biogenesis system. These genes are induced during iron limitation and intracellular growth of Mtb, pointing to their importance during infection.

Effect of Helicobacter pylori and Helminth Coinfection on the Immune Response to Mycobacterium tuberculosis

Tuberculosis remains one of the main causes of morbidity and mortality worldwide despite decades of efforts to eradicate the disease. Although the immune response controls the infection in most infected individuals (90%), the ability of the bacterium to persist throughout the host's life leads to a risk of reactivation. Underlying conditions including human immunodeficiency virus (HIV) infection, organ transplantation, and immunosuppressive therapies are considered risk factors for progression to active disease. However, many individuals infected with Mycobacterium tuberculosis may develop clinical disease in the absence of underlying immunosuppression. It is also possible that unknown conditions may drive the progression to disease. The human microbiota can be an important modulator of the immune system; it can not only trigger inflammatory disorders, but also drive the response to other infectious diseases. In developing countries, chronic mucosal infections with Helicobacter pylori and helminths may be particularly important, as these infections frequently coexist throughout the host's life. However, little is known about the interactions of these pathogens with the immune system and their effects on M. tuberculosis clinical disease, if any. In this review, we discuss the potential effects of H. pylori and helminth co-infections on the immune response to M. tuberculosis. This may contribute to our understanding of host-pathogen interactions and in designing new strategies for the prevention and control of tuberculosis.

Anemia, Iron Status, and HIV: A Systematic Review of the Evidence

People living with HIV (PLWHIV) are at high risk of anemia due to inadequate iron intake, HIV and opportunistic infections, and inflammation, and as a side effect of antiretroviral therapy. Though iron supplementation can reduce iron deficiency anemia (IDA) in the general population, its role in anemia and in the health of PLWHIV is unclear due to concerns that iron supplementation may increase HIV replication and risk of opportunistic infections. We systematically reviewed the evidence on indicators of iron status, iron intake, and clinical outcomes among adults and children with HIV. The evidence suggests that anemia is associated with an increased risk of all-cause mortality and incident tuberculosis among HIV-infected individuals, regardless of anemia type, and the magnitude of the risk is greater with more severe anemia. High serum ferritin is associated with adverse clinical outcomes, although it is unclear if this is due to high iron or inflammation from disease progression. One large observational study found an increased risk of all-cause mortality among HIV-infected adults if they received iron supplementation. Published randomized controlled trials of iron supplementation among PLWHIV tend to have small sample sizes and have been inconclusive in terms of effectiveness and safety. Large randomized trials exploring approaches to safely and effectively provide iron supplementation to PLWHIV are warranted.

Impact of Anemia on Outcome of HIV-Infected Pediatric Patients: A Prospective Observational Study

Introduction

Anemia has been widely reported to predict a poorer prognosis for HIV-infected patients, both in terms of progression to AIDS and in survival. This study aimed to determine the etiology of anemia and its immunological correlation in HIV-infected children.

Materials and Methods

Four hundred and eighty-nine HIV-infected children were screened, of which 86 HIV-infected children with anemia were enrolled. Standard WHO definitions were used for anemia, HIV staging, and growth parameters. Chi-square test, t-tests, and univariate and multivariate logistic regression analyses were used to analyze the data.

Results

Anemia was present in 17.58% (86/489) of HIV-infected children, including 84.6% with moderate anemia, 11.5% with severe anemia, and 2.32% with mild anemia. The mean hemoglobin (Hb) among patients with CD4 count <350 cell/mm³ was lower (7.90 g%) (standard deviation 1.48) compared to those having CD4 >350 cell/mm³ (P = 0.02). Children with severe immunological stage had a significantly lower mean Hb (adjusted estimate: -1.61, 95% confidence interval: -2.65, -0.56) compared to those who had normal immune status. No statistically significant differences in mean Hb at baseline when compared to various demographic and clinical characteristics were observed in unadjusted and adjusted regression models.

Conclusion

Hb is an easy and inexpensive tool to measure and can be used for monitoring disease progression in a resource-limited setting.

Tuning the Anti(myco)bacterial Activity of 3-Hydroxy-4-pyridinone Chelators through Fluorophores

Controlling the sources of Fe available to pathogens is one of the possible strategies that can be successfully used by novel antibacterial drugs. We focused our interest on the design of chelators to address Mycobacterium avium infections. Taking into account the molecular structure of mycobacterial siderophores and considering that new chelators must be able to compete for Fe(III), we selected ligands of the 3-hydroxy-4-pyridinone class to achieve our purpose. After choosing the type of chelating unit it was also our objective to design chelators that could be monitored inside the cell and for that reason we designed chelators that could be functionalized with fluorophores. We didn’t realize at the time that the incorporation a fluorophore, to allow spectroscopic detection, would be so relevant for the antimycobacterial effect or to determine the affinity of the chelators towards biological membranes. From a biophysical perspective, this is a fascinating illustration of the fact that functionalization of a molecule with a particular label may lead to a change in its membrane permeation properties and result in a dramatic change in biological activity. For that reason we believe it is interesting to give a critical account of our entire work in this area and justify the statement “to label means to change”. New perspectives regarding combined therapeutic approaches and the use of rhodamine B conjugates to target closely related problems such as bacterial resistance and biofilm production are also discussed.

The Capacity of Mycobacterium tuberculosis To Survive Iron Starvation Might Enable It To Persist in Iron-Deprived Microenvironments of Human Granulomas

This study was conducted to investigate the role of iron deprivation in the persistence of Mycobacterium tuberculosis. We present evidence of iron restriction in human necrotic granulomas and demonstrate that under iron starvation M. tuberculosis persists, refractive to antibiotics and capable of restarting replication when iron is made available. Transcriptomics and metabolomic analyses indicated that the persistence of M. tuberculosis under iron starvation is dependent on strict control of endogenous Fe utilization and is associated with upregulation of pathogenicity and intrinsic antibiotic resistance determinants. M. tuberculosis mutants compromised in their ability to survive Fe starvation were identified. The findings of this study advance the understanding of the physiological settings that may underpin the chronicity of human tuberculosis (TB) and are relevant to the design of effective antitubercular therapies.

One-third of the world population may harbor persistent M. tuberculosis, causing an asymptomatic infection that is refractory to treatment and can reactivate to become potentially lethal tuberculosis disease. However, little is known about the factors that trigger and maintain M. tuberculosis persistence in infected individuals. Iron is an essential nutrient for M. tuberculosis growth. In this study, we show, first, that in human granulomas the immune defense creates microenvironments in which M. tuberculosis likely experiences drastic Fe deprivation and, second, that Fe-starved M. tuberculosis is capable of long-term persistence without growth. Together, these observations suggest that Fe deprivation in the lung might trigger a state of persistence in M. tuberculosis and promote chronic TB. We also identified vulnerabilities of iron-restricted persistent M. tuberculosis, which can be exploited for the design of new antitubercular therapies.

Human Leukocyte Antigen (HLA) and Immune Regulation: How Do Classical and Non-Classical HLA Alleles Modulate Immune Response to Human Immunodeficiency Virus and Hepatitis C Virus Infections?

The genetic factors associated with susceptibility or resistance to viral infections are likely to involve a sophisticated array of immune response. These genetic elements may modulate other biological factors that account for significant influence on the gene expression and/or protein function in the host. Among them, the role of the major histocompatibility complex in viral pathogenesis in particular human immunodeficiency virus (HIV) and hepatitis C virus (HCV), is very well documented. We, recently, added a novel insight into the field by identifying the molecular mechanism associated with the protective role of human leukocyte antigen (HLA)-B27/B57 CD8⁺ T cells in the context of HIV-1 infection and why these alleles act as a double-edged sword protecting against viral infections but predisposing the host to autoimmune diseases. The focus of this review will be reexamining the role of classical and non-classical HLA alleles, including class Ia (HLA-A, -B, -C), class Ib (HLA-E, -F, -G, -H), and class II (HLA-DR, -DQ, -DM, and -DP) in immune regulation and viral pathogenesis (e.g., HIV and HCV). To our knowledge, this is the very first review of its kind to comprehensively analyze the role of these molecules in immune regulation associated with chronic viral infections.

Serum iron, Folate, Ferritin and CD4 Count in HIV Seropositive Women

HIV infects cluster of differentiation 4 (CD4) T-lymphocytes, monocytes and macrophages resulting in decreased number and function of CD4 cells, changes that affect both cell mediated and humoral immunity. Hematological abnormalities are a common complication of human immune virus (HIV) infection and these abnormalities increase as the disease advances. Anemia is the most common haematological abnormality in HIV seropositive patients and its incidence is strongly associated with the progression of the disease. The aim of present study was to assess the haematological profile of HIV seropositive women and compare them with CD4 count. Two hundred seropositive females (age 18-25 years) attending antiretroviral therapy clinic were selected. Routine gynaecological and haematological investigations were carried out, study samples were drawn and serum iron, folate and ferritin were analysed by chemiluminiscence and CD4 count was determined by using flow-cytometry. Anemia was prevalent in seropositive women especially in those with low CD4 levels. Serum folate and ferritin levels were significantly lower in females with lower CD4 levels. Serum iron levels were higher at low CD4 levels. The mean CD4 count in HIV seropositive anaemic women were lower as compared to non anaemics suggesting that anaemia improves with higher CD4 cell counts. Plasma folate and ferritin levels are sensitive predictor of anaemia in early HIV infections and these patients should have a regular monitoring of their folate and ferritin levels especially with lower CD4 levels.

Plasma Concentrations of Hepcidin in Anemic Zimbabwean Infants

OBJECTIVE

Anemia in infancy is a global public health problem. We evaluated the relative contributions of iron deficiency and inflammation to infant anemia.

METHODS

We measured plasma hepcidin, ferritin, soluble transferrin receptor (sTfR), alpha-1-acid glycoprotein and C-reactive protein (CRP) by ELISA on archived plasma from 289 HIV-unexposed anemic or non-anemic Zimbabwean infants at ages 3 mo, 6 mo and 12 mo. Among anemic infants, we determined the proportion with iron-deficiency anemia (IDA) and anemia of inflammation (AI). We undertook regression analyses of plasma hepcidin and anemia status, adjusting for sex, age and birthweight.

RESULTS

Anemic infants at 3 mo were more stunted and had higher CRP (median 0.45 vs 0.21 mg/L; P = 0.037) and hepcidin (median 14.7 vs 9.7 ng/mL; P = 0.022) than non-anemic infants, but similar levels of ferritin and sTfR; 11% infants had IDA and 15% had AI. Anemic infants at 6 mo had higher hepcidin (median 7.9 vs 4.5 ng/mL; P = 0.016) and CRP (median 2.33 vs 0.32 mg/L; P<0.001), but lower ferritin (median 13.2 vs 25.1 μg/L; P<0.001) than non-anemic infants; 56% infants had IDA and 12% had AI. Anemic infants at 12 mo had lower ferritin (median 3.2 vs 22.2 μg/L; P<0.001) and hepcidin (median 0.9 vs 1.9 ng/mL; P = 0.019), but similar CRP levels; 48% infants had IDA and 8% had AI. Comparing anemic with non-anemic infants, plasma hepcidin was 568% higher, 405% higher and 64% lower at 3 mo, 6 mo and 12 mo, respectively, after adjusting for sex and birthweight (all p<0.01). Plasma hepcidin declined significantly with age among anemic but not non-anemic infants. Girls had 61% higher hepcidin than boys, after adjusting for age, anemia and birthweight (p<0.001).

CONCLUSION

Anemia is driven partly by inflammation early in infancy, and by iron deficiency later in infancy, with plasma hepcidin concentrations reflecting the relative contribution of each. However, there is need to better characterize the drivers of hepcidin during infancy in developing countries.

Minimal impact of an iron-fortified lipid-based nutrient supplement on Hb and iron status: a randomised controlled trial in malnourished HIV-positive African adults starting antiretroviral therapy

Anaemia, redistribution of Fe, malnutrition and heightened systemic inflammation during HIV infection confer an increased risk of morbidity and mortality in HIV patients. We analysed information on Fe status and inflammation from a randomised, double blind, controlled phase-III clinical trial in Lusaka, Zambia and Mwanza, Tanzania. Malnourished patients (n 1815) were recruited at referral to antiretroviral therapy (ART) into a two-stage nutritional rehabilitation programme, randomised to receive a lipid-based nutrient supplement with or without added micronutrients. Fe was included in the intervention arm during the second stage, given from 2 to 6 weeks post-ART. Hb, serum C-reactive protein (CRP), serum ferritin and soluble transferrin receptor (sTfR) were measured at recruitment and 6 weeks post-ART. Multivariable linear regression models were used to assess the impact of the intervention, and the effect of reducing inflammation from recruitment to week 6 on Hb and Fe status. There was no effect of the intervention on Hb, serum ferritin, sTfR or serum CRP. A one-log decrease of serum CRP from recruitment to week 6 was associated with a 1.81 g/l increase in Hb (95% CI 0.85, 2.76; P< 0.001), and a 0.11 log decrease in serum ferritin (95% CI - 0.22, 0.03; P= 0.012) from recruitment to week 6. There was no association between the change in serum CRP and the change in sTfR over the same time period (P= 0.78). In malnourished, HIV-infected adults receiving dietary Fe, a reduction in inflammation in the early ART treatment period appears to be a precondition for recovery from anaemia.

Short communication: high cellular iron levels are associated with increased HIV infection and replication

HIV is a pandemic disease, and many cellular and systemic factors are known to alter its infectivity and replication. Earlier studies had suggested that anemia is common in HIV-infected patients; however, higher iron was also observed in AIDS patients prior to the introduction of antiretroviral therapy (ART). Therefore, the relationship between iron and viral infection is not well delineated. To address this issue, we altered the levels of cellular iron in primary CD4(+) T cells and showed that higher iron is associated with increased HIV infection and replication. In addition, HIV infection alone leads to increased cellular iron, and several ART drugs increase cellular iron independent of HIV infection. Finally, HIV infection is associated with increased serum iron in HIV-positive patients regardless of treatment with ART. These results establish a relationship between iron and HIV infection and suggest that iron homeostasis may be a viable therapeutic target for HIV.

Iron homeostasis and progression to pulmonary tuberculosis disease among household contacts

Early identification of individuals at risk for progressing to active tuberculosis (TB) disease may limit new transmission and improve clinical outcomes. Evidence indicates altered iron homeostasis may identify those at greater risk of disease progression in HIV co-infection. We aimed to investigate iron homeostasis biomarkers as risk factors for progression to TB. Archived plasma samples were analyzed from household contacts of pulmonary TB index cases in The Gambia. Contacts were classified as asymptomatic non-progressors (n = 17) or TB-progressors (n = 10), which included two HIV-infected participants. Iron homeostasis (hemoglobin, ferritin, hepcidin, soluble transferrin receptor, transferrin) was assessed in all contacts at study recruitment. Plasma was collected a median of 910 days prior to TB diagnosis. Low transferrin around the time of known exposure to infectious TB was a disease progression risk factor among all TB-progressors (Poisson incidence rate ratio: 0.55; 95% CI: 0.35-0.89). Iron homeostasis also differed between early and delayed TB-progressors, with higher ferritin and hepcidin concentrations observed among early TB-progressors (mean ferritin 50.2 vs. 26.2 ng/ml; P = 0.027; mean hepcidin 37.7 vs. 5.6 ng/ml; P = 0.036). Iron homeostasis is associated with progression to TB among household contacts. Further studies are needed to elucidate mechanisms and determine the clinical utility of monitoring iron homeostasis biomarkers.

Distinct patterns of hepcidin and iron regulation during HIV-1, HBV, and HCV infections

During HIV type-1 (HIV-1), hepatitis C virus (HCV), and hepatitis B virus (HBV) infections, altered iron balance correlates with morbidity. The liver-produced hormone hepcidin dictates systemic iron homeostasis. We measured hepcidin, iron parameters, cytokines, and inflammatory markers in three cohorts: plasma donors who developed acute HIV-1, HBV, or HCV viremia during the course of donations; HIV-1-positive individuals progressing from early to chronic infection; and chronically HIV-1-infected individuals (receiving antiretroviral therapy or untreated). Hepcidin increased and plasma iron decreased during acute HIV-1 infection, as viremia was initially detected. In patients transitioning from early to chronic HIV-1 infection, hepcidin in the first 60 d of infection positively correlated with the later plasma viral load set-point. Hepcidin remained elevated in individuals with untreated chronic HIV-1 infection and in subjects on ART. In contrast to HIV-1, there was no evidence of hepcidin up-regulation or hypoferremia during the primary viremic phases of HCV or HBV infection; serum iron marginally increased during acute HBV infection. In conclusion, hepcidin induction is part of the pathogenically important systemic inflammatory cascade triggered during HIV-1 infection and may contribute to the establishment and maintenance of viral set-point, which is a strong predictor of progression to AIDS and death. However, distinct patterns of hepcidin and iron regulation occur during different viral infections that have particular tissue tropisms and elicit different systemic inflammatory responses. The hypoferremia of acute infection is therefore a pathogen-specific, not universal, phenomenon.

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.

Potent antimycobacterial activity of the pyridoxal isonicotinoyl hydrazone analog 2-pyridylcarboxaldehyde isonicotinoyl hydrazone: a lipophilic transport vehicle for isonicotinic acid hydrazide

The rise in drug-resistant strains of Mycobacterium tuberculosis is a major threat to human health and highlights the need for new therapeutic strategies. In this study, we have assessed whether high-affinity iron chelators of the pyridoxal isonicotinoyl hydrazone (PIH) class can restrict the growth of clinically significant mycobacteria. Screening a library of PIH derivatives revealed that one compound, namely, 2-pyridylcarboxaldehyde isonicotinoyl hydrazone (PCIH), exhibited nanomolar in vitro activity against Mycobacterium bovis bacille Calmette-Guérin and virulent M. tuberculosis. Interestingly, PCIH is derived from the condensation of 2-pyridylcarboxaldehyde with the first-line antituberculosis drug isoniazid [i.e., isonicotinic acid hydrazide (INH)]. PCIH displayed minimal host cell toxicity and was effective at inhibiting growth of M. tuberculosis within cultured macrophages and also in vivo in mice. Further, PCIH restricted mycobacterial growth at high bacterial loads in culture, a property not observed with INH, which shares the isonicotinoyl hydrazide moiety with PCIH. When tested against Mycobacterium avium, PCIH was more effective than INH at inhibiting bacterial growth in broth culture and in macrophages, and also reduced bacterial loads in vivo. Complexation of PCIH with iron decreased its effectiveness, suggesting that iron chelation may play some role in its antimycobacterial efficacy. However, this could not totally account for its potent efficacy, and structure-activity relationship studies suggest that PCIH acts as a lipophilic vehicle for the transport of its intact INH moiety into the mammalian cell and the mycobacterium. These results demonstrate that iron-chelating agents such as PCIH may be of benefit in the treatment and control of mycobacterial infection.

Lentiviral Nef suppresses iron uptake in a strain specific manner through inhibition of Transferrin endocytosis

BACKGROUND

Increased cellular iron levels are associated with high mortality in HIV-1 infection. Moreover iron is an important cofactor for viral replication, raising the question whether highly divergent lentiviruses actively modulate iron homeostasis. Here, we evaluated the effect on cellular iron uptake upon expression of the accessory protein Nef from different lentiviral strains.

RESULTS

Surface Transferrin receptor (TfR) levels are unaffected by Nef proteins of HIV-1 and its simian precursors but elevated in cells expressing Nefs from most other primate lentiviruses due to reduced TfR internalization. The SIV Nef-mediated reduction of TfR endocytosis is dependent on an N-terminal AP2 binding motif that is not required for downmodulation of CD4, CD28, CD3 or MHCI. Importantly, SIV Nef-induced inhibition of TfR endocytosis leads to the reduction of Transferrin uptake and intracellular iron concentration and is accompanied by attenuated lentiviral replication in macrophages.

CONCLUSION

Inhibition of Transferrin and thereby iron uptake by SIV Nef might limit viral replication in myeloid cells. Furthermore, this new SIV Nef function could represent a virus-host adaptation that evolved in natural SIV-infected monkeys.

Inverse relationship of serum hepcidin levels with CD4 cell counts in HIV-infected patients selected from an Indonesian prospective cohort study

BACKGROUND

Distortion of iron homeostasis may contribute to the pathogenesis of human immunodeficiency virus (HIV) infection and tuberculosis (TB). We studied the association of the central iron-regulatory hormone hepcidin with the severity of HIV and the association between hepcidin and other markers of iron homeostasis with development of TB.

METHODS

Three groups of patients were selected from a prospective cohort of HIV-infected subjects in Bandung, Indonesia. The first group consisted of HIV-infected patients who started TB treatment more than 30 days after cohort enrollment (cases). The second group consisted of HIV-infected patients who were matched for age, gender and CD4 cell count to the cases group (matched controls). The third group consisted of HIV-infected patients with CD4 cell counts above 200 cells/mm(3) (unmatched controls). Iron parameters including hepcidin were compared using samples collected at cohort enrollment, and compared with recently published reference values for serum hepcidin.

RESULTS

A total of 127 HIV-infected patients were included, 42 cases together with 42 matched controls and 43 unmatched controls. Patients with advanced HIV infection had elevated serum hepcidin and ferritin levels. Hepcidin levels correlated inversely with CD4 cells and hemoglobin. Cases had significantly higher hepcidin and ferritin concentrations at cohort enrollment compared to matched controls, but these differences were fully accounted for by the cases who started TB treatment between day 31 and 60 after enrollment. Hepcidin levels were not different in those with or without hepatitis C infection.

CONCLUSION

Iron metabolism is distorted in advanced HIV infection with CD4 cell counts correlating inversely with serum hepcidin levels. High serum hepcidin levels and hyperferritinemia were found in patients starting TB treatment shortly after cohort enrollment, suggesting that these parameters have a predictive value for development of manifest TB in HIV-infected patients.

Iron biology, immunology, aging, and obesity: four fields connected by the small peptide hormone hepcidin

Iron status and immune response become impaired in situations that involve chronic inflammation, such as obesity or aging. Little is known, however, about the additional burden that obesity may place on the iron status and immune response in the elderly. This question is relevant given the rising numbers of elderly obese (BMI >30 kg/m(2)) individuals and the high prevalence of iron deficiency worldwide. Iron is necessary for proper function of both the innate and adaptive immune system. Hepcidin, a peptide hormone that regulates cellular iron export, is essential for the maintenance of iron homeostasis. Therefore, since immune cells require iron for proper function hepcidin may also play an important role in immune response. In this review, we summarize the evidence for hepcidin as a link between the fields of gerontology, obesity, iron biology, and immunology. We also identify several gaps in knowledge and unanswered questions pertaining to iron homeostasis and immunity in obese populations. Finally, we review studies that have shown the impact of weight loss, focusing on calorie restriction, iron homeostasis, and immunity. These studies are important both in elucidating mechanistic links between obesity and health impairments and identifying possible approaches to target immune impairment and iron deficiency as comorbidities of obesity.

Hepcidin and the iron-infection axis

Iron lies at the center of a battle for nutritional resource between higher organisms and their microbial pathogens. The iron status of the human host affects the pathogenicity of numerous infections including malaria, HIV-1, and tuberculosis. Hepcidin, an antimicrobial-like peptide hormone, has emerged as the master regulator of iron metabolism. Hepcidin controls the absorption of dietary iron and the distribution of iron among cell types in the body, and its synthesis is regulated by both iron and innate immunity. We describe how hepcidin integrates signals from diverse physiological inputs, forming a key molecular bridge between iron trafficking and response to infection.

Does venesection reduce HIV viral load in patients with hereditary haemochromatosis?

It is recognized that iron overload is associated with excess mortality in HIV/AIDS, and that this may be due to iron acting as an HIV-1 transcriptional activator. In vitro evidence using iron chelators suggests that therapeutic iron depletion may be beneficial in HIV-1 infection. We describe the clinical course of a Caucasian man with hereditary haemochromatosis and HIV infection where a significant drop in HIV viral load accompanied venesection over an 18-month period in the absence of HAART. We propose that further research should be undertaken to explore the relationship between HIV viral load and serum iron markers in hereditary haemochromatosis, with a view to evaluating the therapeutic benefit of venesection on HIV viral load in this setting.

Development of a sensitive HPLC method to measure in vitro permeability of E- and Z-isomeric forms of thiosemicarbazones in Caco-2 monolayers

In the current study, we developed a HPLC method to quantitatively measure the permeability of the BpT-based chelators, 2-benzoylpyridine 4-ethyl-3-thiosemicarbazone (Bp4eT) and 2-benzoylpyridine 4-allyl-3-thiosemicarbazone (Bp4aT), across human colorectal adenocarcinoma (Caco-2) monolayers as a model of gut absorption. In aqueous solution, Bp4eT and Bp4aT formed inter-convertible Z and E isomers that were resolved by HPLC. Peak area was linear with respect to chelator concentration. Acceptable within-day and between-day precision (<22%) and accuracy (85-115% of true values) were obtained over a range of 1.0-100μM for Bp4eT and 1.5-300μM for Bp4aT. Limits of detection were 0.3μM and 1μM for Bp4eT and Bp4aT, respectively, while corresponding limits of quantification were 1μM and 5μM. Both chelators showed significant ability to chelate iron in THP-1 cells using a calcein-based assay and no apparent cytotoxicity was observed within 24h. Ratios of the apical to basolateral and basolateral to apical transport for Bp4eT were 1.10 and 0.89 at 100μM and 300μM respectively, indicating equal bi-directional movement of the compounds. Similarly, ratios were 0.77 and 0.92 for Bp4aT, respectively. This study demonstrates that Bp4eT and Bp4aT can be efficiently transported through Caco-2 cells and can potentially be formulated for oral delivery.

Transferrin polymorphism and opportunistic infections in HIV-infected women in Rwanda

OBJECTIVE

We investigated the prevalence of opportunistic infections in HIV-infected women according to transferrin (TF) phenotype.

METHODS

We conducted a cross-sectional study among 200 HIV-positive women in the Butare University Teaching Hospital in Rwanda. TF phenotypes were determined using starch gel electrophoresis.

RESULTS

Phenotype frequencies of TF CD, CB and CC were 14.5, 3 and 82.5%, respectively. The homozygous TF DD phenotype was not found. Subjects with TF CD phenotype had a significantly higher prevalence of opportunistic infections than subjects with TF CC phenotype, 76 and 52%, respectively (p = 0.026). In logistic regression, there was a significant correlation between TF phenotypes and opportunistic infections (p = 0.012). Subjects with TF CD phenotype had significantly lower values for TF (p = 0.006) than TF CC subjects. Hematological parameters (RBC, RBC indices, hemoglobin, hematocrit, WBC, neutrophils, lymphocytes, platelets and erythrocyte sedimentation rate), iron, ferritin, TF saturation, C-reactive protein and CD4 count did not differ according to TF phenotype.

CONCLUSION

Subjects with TF CC phenotype have a lower prevalence of opportunistic infections. Iron status may play a role in this association.

Iron status predicts treatment failure and mortality in tuberculosis patients: a prospective cohort study from Dar es Salaam, Tanzania

Background

Experimental data suggest a role for iron in the course of tuberculosis (TB) infection, but there is limited evidence on the potential effects of iron deficiency or iron overload on the progression of TB disease in humans. The aim of the present analysis was to examine the association of iron status with the risk of TB progression and death.

Methodology/Principal Findings

We analyzed plasma samples and data collected as part a randomized micronutrient supplementation trial (not including iron) among HIV-infected and HIV-uninfected TB patients in Dar es Salaam, Tanzania. We prospectively related baseline plasma ferritin concentrations from 705 subjects (362 HIV-infected and 343 HIV-uninfected) to the risk of treatment failure at one month after initiation, TB recurrence and death using binomial and Cox regression analyses. Overall, low (plasma ferritin<30 µg/L) and high (plasma ferritin>150 µg/L for women and>200 µg/L for men) iron status were seen in 9% and 48% of patients, respectively. Compared with normal levels, low plasma ferritin predicted an independent increased risk of treatment failure overall (adjusted RR = 1.95, 95% CI: 1.07 to 3.52) and of TB recurrence among HIV-infected patients (adjusted RR = 4.21, 95% CI: 1.22 to 14.55). High plasma ferritin, independent of C-reactive protein concentrations, was associated with an increased risk of overall mortality (adjusted RR = 3.02, 95% CI: 1.95 to 4.67).

Conclusions/Significance

Both iron deficiency and overload exist in TB patients and may contribute to disease progression and poor clinical outcomes. Strategies to maintain normal iron status in TB patients could be helpful to reduce TB morbidity and mortality.

The prevalence and etiology of anemia among HIV-infected children in India

In this report, the prevalence and multifactorial etiology of anemia among Indian human immunodeficiency virus (HIV)-infected children are described. HIV-infected children aged 2-12 years were prospectively enrolled in 2007-2008. Measured parameters included serum ferritin, vitamin B(12), red-cell folate, soluble transferrin receptor, and C-reactive protein. Children received antiretroviral therapy (ART), iron and, folate supplements as per standard of care. Among 80 enrolled HIV-infected children (mean age 6.8 years), the prevalence of anemia was 52.5%. Etiology of anemia was found to be iron deficiency alone in 38.1%, anemia of inflammation alone in 38.1%, combined iron deficiency and anemia of inflammation alone in 7.1%, vitamin B(12) deficiency in 7.1%, and others in 9.5%. Median iron intake was 5.7 mg/day (recommended dietary allowance 18-26 mg/day). Compared to nonanemic children, anemic children were more likely to be underweight (weight Z-score -2.5 vs. -1.9), stunted (height Z-score -2.6 vs. -1.9), with lower CD4 counts (18% vs. 24%, p < 0.01), and higher log viral load (11.1 vs. 7.1, p < 0.01). Hemoglobin (Hb) improved significantly among those who started ART (baseline Hb 11.6 g/dl, 6-month Hb 12.2 g/dl, p = 0.03). Children taking ART combined with iron supplements experienced a larger increase in Hb compared to those receiving neither ART nor iron supplements (mean Hb change 1.5 g/dl, p < 0.01).

CONCLUSION

Anemia, particularly iron deficiency anemia and anemia of inflammation, is highly prevalent among children with HIV infection. Micronutrient supplements combined with ART improved anemia in HIV-infected children.

Iron deficiency and anemia predict mortality in patients with tuberculosis

Many studies have documented a high prevalence of anemia among tuberculosis (TB) patients and anemia at TB diagnosis has been associated with an increased risk of death. However, little is known about the factors contributing to the development of TB-associated anemia and their importance in TB disease progression. Data from a randomized clinical trial of micronutrient supplementation in patients with pulmonary TB in Tanzania were analyzed. Repeated measures of anemia with iron deficiency, anemia without iron deficiency, and iron deficiency without anemia were assessed as risk factors for treatment failure, TB recurrence, and mortality. The prevalence of anemia (hemoglobin < 110 g/L) at baseline was 64%, more than one-half of which was related to iron deficiency (mean corpuscular volume , 80 fL). We found no evidence of an association between anemia (with or without iron deficiency) or iron deficiency without anemia at baseline and the risk of treatment failure at 1 mo after initiation. Anemia without iron deficiency was associated with an independent, 4-fold increased risk of TB recurrence [adjusted RR = 4.10 (95% CI = 1.88, 8.91); P < 0.001]. Iron deficiency and anemia (with and without iron deficiency) were associated with a 2- to nearly 3-fold independent increase in the risk of death [adjusted RR for iron deficiency without anemia = 2.89 (95% CI = 1.53, 5.47); P = 0.001; anemia without iron deficiency = 2.72 (95% CI = 1.50, 4.93); P = 0.001; iron deficiency anemia = 2.13 (95% CI = 1.10, 4.11); P = 0.02]. Efforts to identify and address the conditions contributing to TB-associated anemia, including iron deficiency, could play an important role in reducing morbidity and mortality in areas heavily affected by TB.

Superinfection in malaria: Plasmodium shows its iron will

After the bite of a malaria-infected mosquito, the Plasmodium sporozoite infects liver cells and produces thousands of merozoites, which then infect red blood cells, causing malaria. In malaria-endemic areas, several hundred infected mosquitoes can bite an individual each year, increasing the risk of superinfection. However, in infants that are yet to acquire immunity, superinfections are infrequent. We have recently shown that blood-stage parasitaemia, above a minimum threshold, impairs the growth of a subsequent sporozoite infection of liver cells. Blood-stage parasites stimulate the production of the host iron-regulatory factor hepcidin, which redistributes iron away from hepatocytes, reducing the development of the iron-dependent liver stage. This could explain why Plasmodium superinfection is not often found in young nonimmune children. Here, we discuss the impact that such protection from superinfection might have in epidemiological settings or in programmes for controlling malaria, as well as how the induction of hepcidin and redistribution of iron might influence anaemia and the outcome of non-Plasmodium co-infections.

Pharmacokinetic/pharmacodynamic-based treatment of disseminated Mycobacterium avium

Disseminated Mycobacterium avium complex (MAC) is treated with a macrolide and ethambutol. However, the kill rates are extremely slow so that therapy takes many months to years to achieve and even then more than 40% of patients are not completely cured. Recent studies have demonstrated that assays that detect extracellular MAC have a limited predictive value. Antibiotics kill at a much slower and more disappointing rate against bacilli within macrophages. Use of pharmacodynamic/pharmacokinetic models has resulted in design of new doses and dosing schedules for disseminated MAC, as well as new susceptibility breakpoints for ethambutol and moxifloxacin.

War-Fe-re: iron at the core of fungal virulence and host immunity

Iron acquisition is a bona fide virulence determinant. The successful colonization of the mammalian host requires that microorganisms overcome the Fe aridity of this milieu in which the levels of circulating Fe are maintained exceedingly low both through the compartmentalization of this nutrient within cells as well as the tight binding of Fe to host circulating proteins and ligands. Microbes notoriously employ multiple strategies for high affinity Fe acquisition from the host that rely either on the expression of receptors for host Fe-binding proteins and ligands, its reduction by cell surface reductases or the utilization of siderophores, small organic molecules with very high affinity for Fe(3+). This review will discuss the multiple mechanisms deployed by fungal pathogens in Fe acquisition focusing on the role of siderophore utilization in virulence as well as host immune strategies of iron withholding and emerging clinical evidence that human disorders of Fe homeostasis can act as modifiers of infectious disease.

Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples

Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.

Micronutrients and HIV infection

The immune system requires several essential micronutrients to maintain an effective immune response. HIV infection destroys the immune system and promotes nutritional deficiencies, which further impair immunity. This article reviews the role of several micronutrients (vitamins A, C, E and D, the B vitamins, and minerals, selenium, iron and zinc) that are relevant for maintaining immune function. In addition, the deficiencies of these micronutrients have been associated with faster progression of HIV-1 disease. This review examines the evidence from observational studies of an association between micronutrient status and HIV disease, as well as the effectiveness of micronutrient supplementation on HIV-disease progression, pregnancy outcomes and nutritional status, among others, utilizing randomized clinical trials. Each micronutrient is introduced with a summary of its functions in human physiology, followed by the presentation of studies conducted in HIV-infected patients in relation to this specific micronutrient. Overall findings and recommendations are then summarized.

Micronutrients, N-acetyl cysteine, probiotics and prebiotics, a review of effectiveness in reducing HIV progression

Low serum concentrations of micronutrients, intestinal abnormalities, and an inflammatory state have been associated with HIV progression. These may be ameliorated by micronutrients, N-acetyl cysteine, probiotics, and prebiotics. This review aims to integrate the evidence from clinical trials of these interventions on the progression of HIV. Vitamin B, C, E, and folic acid have been shown to delay the progression of HIV. Supplementation with selenium, N-acetyl cysteine, probiotics, and prebiotics has considerable potential, but the evidence needs to be further substantiated. Vitamin A, iron, and zinc have been associated with adverse effects and caution is warranted for their use.

Anemia and growth failure among HIV-infected children in India: a retrospective analysis

Background

Anemia and poor nutrition have been previously described as independent risk factors for death among HIV-infected children. We sought to describe nutritional status, anemia burden and HIV disease correlates among infected children in India.

Methods

We analyzed retrospective data from 248 HIV-infected children aged 1–12 years attending three outpatient clinics in South India (2004–2006). Standard WHO definitions were used for anemia, HIV staging and growth parameters. Statistical analysis included chi square, t tests, univariate and multivariate logistic regression analyses.

Results

The overall prevalence of anemia (defined as hemoglobin < 11 gm/dL) was 66%, and 8% had severe anemia (Hb < 7 gm/dL). The proportion of underweight and stunted children in the population was 55% and 46% respectively. Independent risk factors of anemia by multivariate analysis included the pre-school age group (age younger than 6 years) (OR: 2.87; 95% CI: 1.45, 5.70; p < 0.01), rural residence (OR: 12.04; 95% CI: 5.64, 26.00; p < 0.01), advanced HIV disease stage (OR: 6.95; 95% CI: 3.06, 15.79; p < 0.01) and presence of stunting (Height-for-age Z Score < -2) (OR: 3.24; 95% CI: 1.65, 6.35; p < 0.01). Use of iron/multivitamin supplementation was protective against risk of anemia (OR: 0.44; 95% CI: 0.22, 0.90; p = 0.03). Pulmonary tuberculosis was an independent risk factor in multivariate analysis (OR: 3.36; 95% CI: 1.43, 7.89; p < 0.01) when correlated variables such as HIV disease stage and severe immunodeficiency, and nutritional supplement use were not included. Use of antiretroviral therapy (ART) was associated with a reduced risk of anemia (OR: 0.29; 95% CI: 0.16, 0.53; p < 0.01). No significant association was found between anemia and gender, cotrimoxazole, or ART type (zidovudine versus stavudine).

Conclusion

The high prevalence and strong interrelationship of anemia and poor nutrition among HIV-infected children in India, particularly those living in rural areas underscores the need for incorporating targeted nutritional interventions during national scale up of care, support and treatment among HIV-infected children.

Iron-related proteins: candidate urine biomarkers in childhood HIV-associated renal diseases

BACKGROUND

Because of the risk of performing renal biopsies in children with co-morbid conditions, we carried out this study to identify candidate protein biomarkers in the urine of HIV-infected children with renal disease.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

Urine samples from HIV-infected children with biopsy proven HIV-nephropathy (HIVAN; n = 4), HIV-associated Hemolytic Uremic Syndrome (HIV-HUS; n = 2), or no renal disease (n = 3) were analyzed by two-dimensional electrophoresis (2-DE) and proteomic methods. Positive findings were confirmed in HIV-infected children with (n = 20) and without (n = 10) proteinuria using commercially available assays.

RESULTS

By 2-DE analysis, a single urine marker was not sufficient to distinguish children with HIVAN from the others. High urine levels of beta(2)-microglobulin and retinol-binding protein (RBP) suggested the presence of tubular injury. In addition, we found elevated urine levels of iron and the iron-related proteins, transferrin, hemopexin, haptoglobin, lactoferrin, and neutrophil gelatinase-associated lipocalin (NGAL), in children with HIVAN and HIV-HUS. Furthermore, we detected a significant accumulation of iron in the urine and kidneys of HIV-transgenic (Tg) rats with renal disease.

CONCLUSION

These findings suggest that iron and iron-related proteins might be promising candidate urine biomarkers to identify HIV-infected children at risk of developing HIVAN and HIV-HUS. Moreover, based on the results of previous studies, we speculate that the release or accumulation of iron in the kidney of HIV-infected children may contribute to the rapid progression of their renal disease, and could become a new therapeutic target against HIVAN and HIV-HUS.

Iron supplementation for reducing morbidity and mortality in children with HIV

BACKGROUND

The most prevalent haematologic disturbance associated with HIV in children (apart from CD4 lymphocytopenia) is anaemia. Anaemia associated with HIV arises from multiple mechanisms, including the direct inhibitory effect of HIV on red cell precursors, other locally prevalent and/or opportunistic infections, micronutrient deficiency, anaemia of chronic disease, and as a consequence of medicines given for HIV and/or other concurrent illnesses. Iron deficiency is the most common cause of nutritional anaemia globally. There is significant geographical overlap of areas of the world where iron deficiency anaemia (IDA) and paediatric HIV are distributed. Given the high prevalence of IDA, it is likely that many HIV-infected children also are iron deficient. The contribution of iron deficiency to anaemia in HIV-infected children has been described but is incompletely understood. Currently, iron supplementation for anaemic infants and children is routinely practiced without any obvious effect in most developing countries, which bear most of the burden of global paediatric HIV infections.Because iron deficiency and IDA are common in HIV-infected children in high-prevalence areas and because there are concerns about possible deleterious effects of iron, this review aims to assess the evidence for iron supplementation for reducing morbidity and mortality in HIV-infected children.

OBJECTIVES

To determine whether iron supplementation improves clinical, immunologic, and virologic outcomes in children infected with HIV SEARCH STRATEGY: We used the comprehensive search strategy developed specifically by the Cochrane HIV/AIDS Review Group to identify HIV/AIDS randomised controlled trials, and searched the following electronic databases: MEDLINE (searched November 2007); Embase (searched December 2007); and CENTRAL (December 2007). This search was supplemented with a search of AIDSearch (searched December 2007) and NLM Gateway (searched December 2007) to identify relevant conference abstracts, as well as a search of the reference lists of all eligible articles. The search was not limited by language or publication status.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of iron supplementation in any form and dose in HIV-infected children aged 12 years and younger.

DATA COLLECTION AND ANALYSIS

We independently screened the results of the search to select potentially relevant studies and to retrieve the full articles. We independently applied the inclusion criteria to the potentially relevant studies. No studies were identified that fulfilled the selection criteria.

MAIN RESULTS

No RCTs of iron supplementation in HIV-infected children were found.

IMPLICATIONS FOR CLINICAL PRACTICE

The current clinical practice of iron supplementation in HIV-infected children is based on weak evidence comprising observational studies and expert opinions.

IMPLICATIONS FOR RESEARCH

High-quality RCTs of iron supplementation are urgently required, especially in areas with significant overlap of high prevalence of HIV, iron deficiency anaemia, and malaria. Policy makers should prioritise funding for these trials.

Elevated iron stores are associated with HIV disease severity and mortality among postpartum women in Zimbabwe

OBJECTIVES

The relationship between Fe status and HIV infection is complex and poorly understood. While anaemia is a major complication of HIV infection, higher Fe stores may be associated with disease progression. There is limited and conflicting data available from Africa.

DESIGN

Cross-sectional and prospective cohort study. SETTING, SUBJECTS AND METHODS: We examined the association between postpartum Fe status (Hb, serum ferritin (SF) and transferrin receptor (TfR)) and viral load (VL) and HIV-related mortality in 643 HIV-positive Zimbabwean women over a period of 12 months.

RESULTS

In non-anaemic women a log10 increase in SF was associated with a 2.3-fold increase in VL (P = 0.019); this association was absent in anaemic women. In prospective analyses, a log10 increase in SF was associated with a 4-fold increase in mortality by 12 months (P = 0.002). Hb was negatively associated with VL (P = 0.001) and mortality (P = 0.047). The adverse associations between SF and both VL and mortality were found at SF concentrations > 45 microg/l (P < 0.05). Controlling for alpha1 acid glycoprotein, a marker of inflammation, attenuated the association between both SF and VL and mortality, but these remained significant.

CONCLUSIONS

These results are consistent with the hypothesis that high Fe stores have adverse consequences in HIV infection. If adverse consequences are real, our data suggest that they occur at SF concentrations exceeding those consistent with adequate Fe nutriture.

Viral infection and iron metabolism

Fundamental cellular operations, including DNA synthesis and the generation of ATP, require iron. Viruses hijack cells in order to replicate, and efficient replication needs an iron-replete host. Some viruses selectively infect iron-acquiring cells by binding to transferrin receptor 1 during cell entry. Other viruses alter the expression of proteins involved in iron homeostasis, such as HFE and hepcidin. In HIV-1 and hepatitis C virus infections, iron overload is associated with poor prognosis and could be partly caused by the viruses themselves. Understanding how iron metabolism and viral infection interact might suggest new methods to control disease.

Elevated iron status strongly predicts mortality in West African adults with HIV infection

OBJECTIVE

To comprehensively assess iron status and determine whether elevated iron status, like anemia, predicts mortality.

METHODS

We followed 1362 Gambian adults (53% female) in an HIV-seroprevalent clinic-based cohort over 11.5 years to ascertain all-cause mortality. Baseline iron status (iron, soluble transferrin receptor [sTfR], transferrin, ferritin, transferrin saturation, log [transferrin receptor: ferritin]), age, gender, ethnicity, hemoglobin, body mass index, HIV type, absolute CD4 count, malaria status, and [alpha]-(1)-antichymotrypsin were measured.

RESULTS

The mortality rate was 25.9/100 person-years. Elevated iron universally predicted greater mortality compared to normal iron status for all iron status indices, with the exception of sTfR in unadjusted models. In fully adjusted models, transferrin (elevated vs. normal, hazard ratio [HR]: 1.77; 95% confidence interval [CI]: 1.30 to 2.42; P < 0.001), ferritin (elevated vs. normal, HR: 1.40; 95% CI: 1.07 to 1.83; P = 0.014), and the combined iron status index (highly elevated vs. normal, HR: 2.20; 95% CI: 1.16 to 4.18; P = 0.016) remained significant predictors. As expected, hemoglobin (Hb) concentration and absolute CD4 counts were each inversely associated with mortality.

CONCLUSIONS

Elevated iron status predicts mortality in HIV infection, even after adjustment for immunosuppression and other confounders. This finding has implications in the clinical monitoring of disease progression and for iron-supplementation practices in areas of high HIV prevalence.

Ferritin levels during structured treatment interruption of highly active antiretroviral therapy

OBJECTIVE

The aim of the study was to investigate the influence of highly active antiretroviral therapy (HAART) on iron status and, conversely, the influence of iron status on the response to HAART.

METHODS

Ferritin levels were retrospectively determined in stored plasma from 138 HAART-naïve, moderately immunosuppressed HIV-infected Thai patients participating in a structured treatment interruption trial. Ferritin levels were determined at three predefined time-points: (1) HAART initiation; (2) HAART discontinuation; and (3) HAART resumption.

RESULTS

At baseline, 31% and 16% of the HIV-infected patients included in the study had high (>200 ng/mL) and low (<30 ng/mL) ferritin levels, respectively. Ninety-five per cent of patients with low ferritin levels were female. Ferritin decreased significantly during the interruption phase of HAART (-8.8 ng/mL; P=0.0005) but remained elevated in 62% of the patients with high baseline levels. A low baseline ferritin level was associated with a shorter time (P=0.041) to reach the CD4 cell target for HAART interruption (350 cells/microL), compared with a normal or high baseline ferritin level. Moreover, in a multivariate model, the relative risk (RR) of arriving at this CD4 cell target was significantly higher [RR 1.81; 95% confidence interval (CI) 1.05-3.14] in patients with low baseline ferritin. It is unlikely that inflammation affected ferritin in our patients, as mean levels of C-reactive protein were not elevated in patients with either high or low ferritin levels.

CONCLUSIONS

Both high and low ferritin levels were highly prevalent in moderately immunosuppressed HIV-positive Thai patients. Structured treatment interruption of HAART resulted in a significant decrease in overall ferritin levels. Furthermore, subjects with low baseline ferritin levels had a faster and greater CD4 response to HAART, suggesting a potential beneficial effect of iron deficiency on immunological recovery after initiation of HAART.

Iron status is an important cause of anemia in HIV-infected Tanzanian women but is not related to accelerated HIV disease progression

In HIV-infected populations from developing countries, it is unclear what proportion of anemia is attributable to iron deficiency (ID) and whether high body iron stores worsen HIV disease progression. We therefore evaluated these research questions in 584 HIV-infected Tanzanian women. Hemoglobin (Hb), serum ferritin (SF), serum transferrin receptor (sTfR), and C-reactive protein (CRP) concentrations were evaluated between 13 and 43 wk after women gave birth. ID was defined as SF or sTfR outside normal ranges, and ID anemia (IDA) as ID plus low Hb. In multivariate Cox regression models, the association between SF and HIV disease progression was assessed. Participants received iron + folate supplements during pregnancy. Hb (r = -0.159; P = 0.0001), SF (r = 0.355; P < 0.0001), and sTfR/log SF index (r = -0.119; P = 0.004) were related to CRP, whereas sTfR (r = 0.029; P = 0.48) was not. Prevalence estimates were 39.7% for ID and 23.6% for IDA. ID was associated with 48.9% of anemia cases. Categories of SF were not significantly associated with HIV-related mortality or progression to stage 4. Nevertheless, SF > 150.0 microg/L was related to a nonsignificantly elevated risk of progression to stage 4 (rate ratio = 1.78; 95% CI = 0.68-4.64; P = 0.24) compared with SF < 12.0 microg/L. In HIV-infected, parous women from sub-Saharan Africa, ID is of moderately high prevalence and is an important underlying cause of anemia. High storage iron does not appear to be related to HIV disease progression in this population, but more research on the role of iron during HIV disease is needed.

Effect of micronutrients and iron supplementation on hemoglobin, iron status, and plasma hepatitis C and HIV RNA levels in female injection drug users: a controlled clinical trial

BACKGROUND

Iron deficiency is common among female injection drug users, but it is unclear whether iron supplementation can reduce anemia and improve iron status without increasing plasma hepatitis C virus (HCV) or HIV RNA levels.

METHODS

We conducted a phase 3, double-blind, randomized, controlled clinical trial of daily micronutrients with 18 mg of iron (iron group) versus micronutrients without iron (control group) for 12 months among hepatitis C-positive female injection drug users in Baltimore, Maryland. The main outcome measures were hemoglobin, markers of iron status, plasma HCV RNA, plasma HIV RNA, and liver enzymes at 6 and 12 months of follow-up.

RESULTS

Four hundred fifty-eight women (320 HIV-negative and 138 HIV-positive) enrolled in the trial. There were no significant differences in the proportion of women with anemia, ferritin<30 ng/mL, log10 plasma HCV RNA, or log10 plasma HIV RNA between treatment groups at enrollment. The proportion with anemia in the iron and control groups, respectively, was 20.7% versus 31.3% (P=0.026) at 6 months and 26.2% versus 30.4% (P=0.5) at 12 months; with ferritin<30 ng/mL, the proportion was 29.2% versus 55.5% (P<0.0001) at 6 months and 26.2% versus 46.9% (P=0.0018) at 12 months. In the iron and control groups, respectively, mean log10 plasma HCV RNA (IU/mL) was 5.2 versus 5.2 (P=0.86) at 6 months and 5.4 versus 5.3 (P=0.6) at 12 months. Among HIV-positive subjects, mean log10 plasma RNA (copies/mL) in the iron and placebo groups, respectively, was 3.8 versus 3.7 (P=0.75) at 6 months and 3.7 versus 4.1 (P=0.19) at 12 months. There were no significant differences in liver enzyme levels between the treatment groups at enrollment, 6 months, and 12 months.

CONCLUSIONS

A daily micronutrient supplement with iron can reduce anemia and improve iron status in female injection drug users without increasing plasma HCV or HIV RNA levels or altering liver enzymes.

Host-pathogen interactions: the role of iron

Iron is essential for both host and pathogen, and complex systems of acquisition and utilization have evolved in competition. Our increasing knowledge of the basic mechanisms of homeostasis and their adaptation during deficiency, overload, and infection indicate that iron is a key regulator of host pathogen interactions. This review concentrated on the clinical and public health aspects of the interaction between the iron acquisition mechanisms of select pathogens of public health importance with host iron homeostasis. Knowledge of these interactions is essential in assessing likely morbidity responses to supplementation.