Effect of deferiprone, an oral iron chelator, in diabetic and non-diabetic glomerular disease

The main molecular mechanisms of ferroptosis and its role in chronic kidney disease

The term ferroptosis, coined in 2012, has been widely applied in various disease research fields. Ferroptosis is a newly regulated form of cell death distinct from apoptosis, necrosis, and autophagy, the mechanisms of which have been extensively studied. Chronic kidney disease, characterized by renal dysfunction, is a common disease severely affecting human health, with its occurrence and development influenced by multiple factors and leading to dysfunction in multiple systems. It often lacks obvious clinical symptoms in the early stages, and thus, diagnosis is typically made in the later stages, complicating treatment. While research on ferroptosis and acute kidney injury has made continuous progress, studies on the association between ferroptosis and chronic kidney disease remain limited. This review aims to summarize chronic kidney disease, investigate the mechanism and regulation of ferroptosis, and attempt to elucidate the role of ferroptosis in the occurrence and development of chronic kidney disease.

Iron chelation mitigates mitochondrial dysfunction and oxidative stress by enhancing nrf2-mediated antioxidant responses in the renal cortex of a murine model of type 2 diabetes

Renal iron overload is a common complication of diabetes that leads to oxidative stress and mitochondrial dysfunction in the kidneys. This study investigated the effects of iron chelation using deferiprone on mitochondrial dysfunction and oxidative stress in the renal cortex of a murine model of type 2 diabetes. Diabetic rats were treated with deferiprone (50 mg/kg BW) for 16 weeks. Our results show that iron chelation with deferiprone significantly increased the nuclear accumulation of Nrf2, a transcription factor that regulates the expression of antioxidant enzymes. This led to enhanced antioxidant capacity, reduced production of reactive oxygen species, and improved mitochondrial bioenergetic function in diabetic rats. However, chronic iron chelation led to altered mitochondrial respiration and increased oxidative stress in non-diabetic rats. In conclusion, our findings suggest that iron chelation with deferiprone protects mitochondrial bioenergetics and mitigates oxidative stress in the renal cortex, involving the NRF2 pathway in type 2 diabetes.

Iron homeostasis, recycling and vulnerability in the stressed kidney: A neglected dimension of iron-deficient heart failure

The available evidence suggests that the kidney may contribute importantly to the development of an iron deficiency state in patients with heart failure and may be injured by therapeutic efforts to achieve iron repletion. The exceptional workload of the proximal renal tubule requires substantial quantities of iron for ATP synthesis, which it derives from Fe3+ bound to transferrin in the bloodstream. Following ferrireduction, Fe2+ is conveyed by divalent transporters (e.g. DMT1) out of the endosome of the proximal renal tubule, and highly reactive Fe2+ can be directed to the mitochondria, sequestered safely in a ferritin nanocage or exported through the actions of hepcidin-inhibitable ferroportin. The actions of ferroportin, together with transferrin endocytosis and DMT1-mediated transport, play a key role in the recycling of iron from the tubular fluid into the bloodstream and preventing the loss of filtered iron in the urine. Activation of endogenous neurohormonal systems and proinflammatory signalling in heart failure decrease megalin-mediated uptake and DMT1 expression, and increase hepcidin-mediated suppression of ferroportin, promoting the loss of iron in the urine and contributing to the development of an iron deficiency state. Furthermore, the failure of ferroportin-mediated efflux at the basolateral membrane heightens the susceptibility of the renal tubules to cytosolic excesses of Fe2+, causing lipid peroxidation and synchronized cell death (ferroptosis) through the iron-dependent free radical theft of electrons from lipids in the cell membrane. Ferroptosis is a central mechanism to most disorders that can cause acute and chronic kidney disease. Short-term bolus administration of intravenous iron can cause oxidative stress and is accompanied by markers of renal injury. Experimentally, long-term maintenance of an iron-replete state is accompanied by accelerated loss of nephrons, oxidative stress, inflammation and fibrosis. Intravenous iron therapy increases glomerular filtration rate rapidly in patients with heart failure (perhaps because of a haemodynamic effect) but not in patients with chronic kidney disease, and the effects of intravenous iron on the progression of renal dysfunction in the long-term trials - AFFIRM-AHF, IRONMAN and HEART-FID - have not yet been reported. Given the potential role of dysregulated renal iron homeostasis in the pathogenesis of iron deficiency and the known vulnerability of the kidney to intravenous iron, the appropriate level of iron repletion with respect to the risk of acute and chronic kidney injury in patients with heart failure requires further study.

Advances of Iron and Ferroptosis in Diabetic Kidney Disease

Diabetes mellitus presents a significant threat to human health because it disrupts energy metabolism and gives rise to various complications, including diabetic kidney disease (DKD). Metabolic adaptations occurring in the kidney in response to diabetes contribute to the pathogenesis of DKD. Iron metabolism and ferroptosis, a recently defined form of cell death resulting from iron-dependent excessive accumulation of lipid peroxides, have emerged as crucial players in the progression of DKD. In this comprehensive review, we highlight the profound impact of adaptive and maladaptive responses regulating iron metabolism on the progression of kidney damage in diabetes. We summarize the current understanding of iron homeostasis and ferroptosis in DKD. Finally, we propose that precise manipulation of iron metabolism and ferroptosis may serve as potential strategies for kidney management in diabetes.

The Importance and Essentiality of Natural and Synthetic Chelators in Medicine: Increased Prospects for the Effective Treatment of Iron Overload and Iron Deficiency

The supply and control of iron is essential for all cells and vital for many physiological processes. All functions and activities of iron are expressed in conjunction with iron-binding molecules. For example, natural chelators such as transferrin and chelator-iron complexes such as haem play major roles in iron metabolism and human physiology. Similarly, the mainstay treatments of the most common diseases of iron metabolism, namely iron deficiency anaemia and iron overload, involve many iron-chelator complexes and the iron-chelating drugs deferiprone (L1), deferoxamine (DF) and deferasirox. Endogenous chelators such as citric acid and glutathione and exogenous chelators such as ascorbic acid also play important roles in iron metabolism and iron homeostasis. Recent advances in the treatment of iron deficiency anaemia with effective iron complexes such as the ferric iron tri-maltol complex (feraccru or accrufer) and the effective treatment of transfusional iron overload using L1 and L1/DF combinations have decreased associated mortality and morbidity and also improved the quality of life of millions of patients. Many other chelating drugs such as ciclopirox, dexrazoxane and EDTA are used daily by millions of patients in other diseases. Similarly, many other drugs or their metabolites with iron-chelation capacity such as hydroxyurea, tetracyclines, anthracyclines and aspirin, as well as dietary molecules such as gallic acid, caffeic acid, quercetin, ellagic acid, maltol and many other phytochelators, are known to interact with iron and affect iron metabolism and related diseases. Different interactions are also observed in the presence of essential, xenobiotic, diagnostic and theranostic metal ions competing with iron. Clinical trials using L1 in Parkinson's, Alzheimer's and other neurodegenerative diseases, as well as HIV and other infections, cancer, diabetic nephropathy and anaemia of inflammation, highlight the importance of chelation therapy in many other clinical conditions. The proposed use of iron chelators for modulating ferroptosis signifies a new era in the design of new therapeutic chelation strategies in many other diseases. The introduction of artificial intelligence guidance for optimal chelation therapeutic outcomes in personalised medicine is expected to increase further the impact of chelation in medicine, as well as the survival and quality of life of millions of patients with iron metabolic disorders and also other diseases.

Astragaloside IV Mitigated Diabetic Nephropathy by Restructuring Intestinal Microflora and Ferroptosis

SCOPE

To investigate the underlying mechanism of Astragaloside IV (AS-IV) in ameliorating diabetic nephropathy (DN) by regulating intestinal microbiota ecology and intestinal mucosal barrier.

METHODS AND RESULTS

Genetically db/db mice are used to establish DN mouse model to monitor the therapeutic effects of AS-IV and fecal microbiota transplantation (FMT) against DN. Supplementation with AS-IV dramatically attenuates several clinical indicators of DN in db/db mice. In addition, AS-IV markedly improves intestinal barrier function, modifies intestinal permeability, and reduces inflammation. Moreover, AS-IV treatment remarkably improves intestinal dysbiosis in db/db mice, characterized by an elevated abundance of Akkermansia, Ligilactobacillus, and Lactobacillus, indicating the fundamental role of the microbiome in DN progression. Furthermore, FMT derived from AS-IV-treated db/db mice is potentially efficient in antagonizing renal dysfunction, rebalancing gut microbiota, and improving intestinal permeability in recipient db/db mice. AS-IV-enriched Akkermansia muciniphila dramatically alleviates DN and intestinal mucosal barrier dysfunction in db/db mice. Intriguingly, AS-IV intervention dramatically diminishes ferroptosis in the kidney and colon tissues. CONCLUSION : Intestinal microbiome alterations and ferroptosis modulation by AS-IV may play instrumental roles in this mechanism, providing compelling evidence for the role of the gut-renal axis in DN.

Drug Selection and Posology, Optimal Therapies and Risk/Benefit Assessment in Medicine: The Paradigm of Iron-Chelating Drugs

The design of clinical protocols and the selection of drugs with appropriate posology are critical parameters for therapeutic outcomes. Optimal therapeutic protocols could ideally be designed in all diseases including for millions of patients affected by excess iron deposition (EID) toxicity based on personalised medicine parameters, as well as many variations and limitations. EID is an adverse prognostic factor for all diseases and especially for millions of chronically red-blood-cell-transfused patients. Differences in iron chelation therapy posology cause disappointing results in neurodegenerative diseases at low doses, but lifesaving outcomes in thalassemia major (TM) when using higher doses. In particular, the transformation of TM from a fatal to a chronic disease has been achieved using effective doses of oral deferiprone (L1), which improved compliance and cleared excess toxic iron from the heart associated with increased mortality in TM. Furthermore, effective L1 and L1/deferoxamine combination posology resulted in the complete elimination of EID and the maintenance of normal iron store levels in TM. The selection of effective chelation protocols has been monitored by MRI T2* diagnosis for EID levels in different organs. Millions of other iron-loaded patients with sickle cell anemia, myelodysplasia and haemopoietic stem cell transplantation, or non-iron-loaded categories with EID in different organs could also benefit from such chelation therapy advances. Drawbacks of chelation therapy include drug toxicity in some patients and also the wide use of suboptimal chelation protocols, resulting in ineffective therapies. Drug metabolic effects, and interactions with other metals, drugs and dietary molecules also affected iron chelation therapy. Drug selection and the identification of effective or optimal dose protocols are essential for positive therapeutic outcomes in the use of chelating drugs in TM and other iron-loaded and non-iron-loaded conditions, as well as general iron toxicity.

The Vital Role Played by Deferiprone in the Transition of Thalassaemia from a Fatal to a Chronic Disease and Challenges in Its Repurposing for Use in Non-Iron-Loaded Diseases

The iron chelating orphan drug deferiprone (L1), discovered over 40 years ago, has been used daily by patients across the world at high doses (75-100 mg/kg) for more than 30 years with no serious toxicity. The level of safety and the simple, inexpensive synthesis are some of the many unique properties of L1, which played a major role in the contribution of the drug in the transition of thalassaemia from a fatal to a chronic disease. Other unique and valuable clinical properties of L1 in relation to pharmacology and metabolism include: oral effectiveness, which improved compliance compared to the prototype therapy with subcutaneous deferoxamine; highly effective iron removal from all iron-loaded organs, particularly the heart, which is the major target organ of iron toxicity and the cause of mortality in thalassaemic patients; an ability to achieve negative iron balance, completely remove all excess iron, and maintain normal iron stores in thalassaemic patients; rapid absorption from the stomach and rapid clearance from the body, allowing a greater frequency of repeated administration and overall increased efficacy of iron excretion, which is dependent on the dose used and also the concentration achieved at the site of drug action; and its ability to cross the blood-brain barrier and treat malignant, neurological, and microbial diseases affecting the brain. Some differential pharmacological activity by L1 among patients has been generally shown in relation to the absorption, distribution, metabolism, elimination, and toxicity (ADMET) of the drug. Unique properties exhibited by L1 in comparison to other drugs include specific protein interactions and antioxidant effects, such as iron removal from transferrin and lactoferrin; inhibition of iron and copper catalytic production of free radicals, ferroptosis, and cuproptosis; and inhibition of iron-containing proteins associated with different pathological conditions. The unique properties of L1 have attracted the interest of many investigators for drug repurposing and use in many pathological conditions, including cancer, neurodegenerative conditions, microbial conditions, renal conditions, free radical pathology, metal intoxication in relation to Fe, Cu, Al, Zn, Ga, In, U, and Pu, and other diseases. Similarly, the properties of L1 increase the prospects of its wider use in optimizing therapeutic efforts in many other fields of medicine, including synergies with other drugs.

Deferiprone and Iron-Maltol: Forty Years since Their Discovery and Insights into Their Drug Design, Development, Clinical Use and Future Prospects

The historical insights and background of the discovery, development and clinical use of deferiprone (L1) and the maltol-iron complex, which were discovered over 40 years ago, highlight the difficulties, complexities and efforts in general orphan drug development programs originating from academic centers. Deferiprone is widely used for the removal of excess iron in the treatment of iron overload diseases, but also in many other diseases associated with iron toxicity, as well as the modulation of iron metabolism pathways. The maltol-iron complex is a recently approved drug used for increasing iron intake in the treatment of iron deficiency anemia, a condition affecting one-third to one-quarter of the world's population. Detailed insights into different aspects of drug development associated with L1 and the maltol-iron complex are revealed, including theoretical concepts of invention; drug discovery; new chemical synthesis; in vitro, in vivo and clinical screening; toxicology; pharmacology; and the optimization of dose protocols. The prospects of the application of these two drugs in many other diseases are discussed under the light of competing drugs from other academic and commercial centers and also different regulatory authorities. The underlying scientific and other strategies, as well as the many limitations in the present global scene of pharmaceuticals, are also highlighted, with an emphasis on the priorities for orphan drug and emergency medicine development, including the roles of the academic scientific community, pharmaceutical companies and patient organizations.

New Iron Metabolic Pathways and Chelation Targeting Strategies Affecting the Treatment of All Types and Stages of Cancer

There is new and increasing evidence from in vitro, in vivo and clinical studies implicating the pivotal role of iron and associated metabolic pathways in the initiation, progression and development of cancer and in cancer metastasis. New metabolic and toxicity mechanisms and pathways, as well as genomic, transcription and other factors, have been linked to cancer and many are related to iron. Accordingly, a number of new targets for iron chelators have been identified and characterized in new anticancer strategies, in addition to the classical restriction of/reduction in iron supply, the inhibition of transferrin iron delivery, the inhibition of ribonucleotide reductase in DNA synthesis and high antioxidant potential. The new targets include the removal of excess iron from iron-laden macrophages, which affects anticancer activity; the modulation of ferroptosis; ferritin iron removal and the control of hyperferritinemia; the inhibition of hypoxia related to the role of hypoxia-inducible factor (HIF); modulation of the function of new molecular species such as STEAP4 metalloreductase and the metastasis suppressor N-MYC downstream-regulated gene-1 (NDRG1); modulation of the metabolic pathways of oxidative stress damage affecting mitochondrial function, etc. Many of these new, but also previously known associated iron metabolic pathways appear to affect all stages of cancer, as well as metastasis and drug resistance. Iron-chelating drugs and especially deferiprone (L1), has been shown in many recent studies to fulfill the role of multi-target anticancer drug linked to the above and also other iron targets, and has been proposed for phase II trials in cancer patients. In contrast, lipophilic chelators and their iron complexes are proposed for the induction of ferroptosis in some refractory or recurring tumors in drug resistance and metastasis where effective treatments are absent. There is a need to readdress cancer therapy and include therapeutic strategies targeting multifactorial processes, including the application of multi-targeting drugs involving iron chelators and iron-chelator complexes. New therapeutic protocols including drug combinations with L1 and other chelating drugs could increase anticancer activity, decrease drug resistance and metastasis, improve treatments, reduce toxicity and increase overall survival in cancer patients.

Deferiprone: A Forty-Year-Old Multi-Targeting Drug with Possible Activity against COVID-19 and Diseases of Similar Symptomatology

The need for preparing new strategies for the design of emergency drug therapies against COVID-19 and similar diseases in the future is rather urgent, considering the high rate of morbidity and especially mortality associated with COVID-19, which so far has exceeded 18 million lives. Such strategies could be conceived by targeting the causes and also the serious toxic side effects of the diseases, as well as associated biochemical and physiological pathways. Deferiprone (L1) is an EMA- and FDA-approved drug used worldwide for the treatment of iron overload and also other conditions where there are no effective treatments. The multi-potent effects and high safety record of L1 in iron loaded and non-iron loaded categories of patients suggests that L1 could be developed as a “magic bullet” drug against COVID-19 and diseases of similar symptomatology. The mode of action of L1 includes antiviral, antimicrobial, antioxidant, anti-hypoxic and anti-ferroptotic effects, iron buffering interactions with transferrin, iron mobilizing effects from ferritin, macrophages and other cells involved in the immune response and hyperinflammation, as well as many other therapeutic interventions. Similarly, several pharmacological and other characteristics of L1, including extensive tissue distribution and low cost of production, increase the prospect of worldwide availability, as well as many other therapeutic approach strategies involving drug combinations, adjuvant therapies and disease prevention.

Reduction in Ferritin Concentrations among Patients Consuming a Dark-Green Leafy Vegetable-Rich, Low Inflammatory Foods Everyday (LIFE) Diet

Background

Ferritin is an iron-containing protein and acute-phase reactant, which may be elevated due to systemic iron overload or inflammation. Various diseases are associated with excess iron, but therapeutic iron chelation is suboptimal. Prior studies suggest that several plant phytochemicals possess iron-chelating properties, indicating that a plant-based diet may benefit patients with iron overload.

Objectives

The aim was to investigate whether patients who consume a nutrient-dense, dark-green leafy vegetable-rich diet, called the Low Inflammatory Foods Everyday (LIFE) diet, experience reductions in ferritin concentrations.

Methods

This was a retrospective study in which patients were intensively counseled to follow the LIFE diet. Compliance was assessed by patient interviews and serum B-carotene measurements. Primary outcomes included changes in ferritin, B-carotene, and C-reactive protein (CRP). Patients with elevated CRP concentrations at baseline were excluded in order to separate the impact of inflammation from iron overload on ferritin concentrations. Premenopausal women, who lose iron from menstruation, were also excluded.

Results

Thirty-two patients met the inclusion criteria. The median follow-up was 183 d.   Following the dietary intervention, ferritin decreased (-81 μg/L, P = 0.006) and B-carotene increased (46 μg/L, P < 0.0001), whereas CRP remained unchanged (-0.02 mg/L, P = 0.86). Adherent patients had greater reductions in ferritin compared with nonadherent patients (-138 μg/L vs. 15 μg/L, P = 0.001). Among all patients, there was an inverse relation between B-carotene and ferritin (-2.02, P = 0.03).

Conclusions

The LIFE diet, or similar dark-green leafy vegetable-rich, whole-food plant-based diets, may benefit patients with disorders of iron overload and iron-induced oxidative stress.

Therapeutic Implications of Ferroptosis in Renal Fibrosis

Renal fibrosis is a common feature of chronic kidney disease (CKD), and can lead to the destruction of normal renal structure and loss of kidney function. Little progress has been made in reversing fibrosis in recent years. Ferroptosis is more immunogenic than apoptosis due to the release and activation of damage-related molecular patterns (DAMPs) signals. In this paper, the relationship between renal fibrosis and ferroptosis was reviewed from the perspective of iron metabolism and lipid peroxidation, and some pharmaceuticals or chemicals associated with both ferroptosis and renal fibrosis were summarized. Other programmed cell death and ferroptosis in renal fibrosis were also firstly reviewed for comparison and further investigation.

Kidney tubule iron loading in experimental focal segmental glomerulosclerosis

Kidney iron deposition may play a role in the progression of tubulointerstitial injury during chronic kidney disease. Here, we studied the molecular mechanisms of kidney iron loading in experimental focal segmental glomerulosclerosis (FSGS) and investigated the effect of iron-reducing interventions on disease progression. Thy-1.1 mice were injected with anti-Thy-1.1 monoclonal antibody (mAb) to induce proteinuria. Urine, blood and tissue were collected at day (D)1, D5, D8, D15 and D22 after mAb injection. Thy-1.1 mice were subjected to captopril (CA), iron-deficient (ID) diet or iron chelation (deferoxamine; DFO). MAb injection resulted in significant albuminuria at all time points (p < 0.01). Kidney iron loading, predominantly in distal tubules, increased in time, along with urinary kidney injury molecule-1 and 24p3 concentration, as well as kidney mRNA expression of Interleukin-6 (Il-6) and Heme oxygenase-1 (Ho-1). Treatment with CA, ID diet or DFO significantly reduced kidney iron deposition at D8 and D22 (p < 0.001) and fibrosis at D22 (p < 0.05), but not kidney Il-6. ID treatment increased kidney Ho-1 (p < 0.001). In conclusion, kidney iron accumulation coincides with progression of tubulointerstitial injury in this model of FSGS. Reduction of iron loading halts disease progression. However, targeted approaches to prevent excessive kidney iron loading are warranted to maintain the delicate systemic and cellular iron balance.

Serum catalytic iron and progression of chronic kidney disease: findings from the ICKD study

BACKGROUND

The non-transferrin bound catalytic iron moiety catalyses production of toxic reactive oxygen species and is associated with adverse outcomes. We hypothesized that serum catalytic iron (SCI) is associated with progression of chronic kidney disease (CKD).

METHODS

Baseline samples of the Indian Chronic Kidney Disease participants with at least one follow up visit were tested for total iron, iron binding capacity, transferrin saturation, SCI, ferritin and hepcidin. SCI was measured using the bleomycin-detectable iron assay that detects biologically active iron. Association with the incidence of major kidney endpoints, (MAKE, a composite of kidney death, kidney failure or > 40% loss of eGFR) was examined using Cox proportional hazards model adjusted for sex and age.

RESULTS

2002 subjects (49.9 ± 11.6 years, 68.1% males, baseline eGFR 41.01 ml/min/1.73m2) were enrolled. After a median follow up of 12.6 (12.2, 16.7) months, the composite MAKE occurred in 280 (14%). After adjusting for age and sex, increase from 25th to 75th percentile in SCI, transferrin saturation, ferritin and hepcidin were associated with 78% (43-122%), 34% (10-62%), 57% (24-100%) and 74% (35-124%) increase in hazard of MAKE, respectively. SCI was associated with MAKE and kidney failure after adjustment for occupational exposure, hypertension, diabetes, tobacco, alcohol use, history of AKI, baseline eGFR, uACR, and allowing baseline hazard to vary by centre.

CONCLUSIONS

SCI is strongly and independently associated with composite MAKE in patients with mild to moderate CKD. Confirmation in other studies will allow consideration of SCI as a risk marker and treatment target.

Antioxidant Activity of Deferasirox and Its Metal Complexes in Model Systems of Oxidative Damage: Comparison with Deferiprone

Deferasirox is an orally active, lipophilic iron chelating drug used on thousands of patients worldwide for the treatment of transfusional iron overload. The essential transition metals iron and copper are the primary catalysts of reactive oxygen species and oxidative damage in biological systems. The redox effects of deferasirox and its metal complexes with iron, copper and other metals are of pharmacological, toxicological, biological and physiological importance. Several molecular model systems of oxidative damage caused by iron and copper catalysis including the oxidation of ascorbic acid, the peroxidation of linoleic acid micelles and the oxidation of dihydropyridine have been investigated in the presence of deferasirox using UV-visible and NMR spectroscopy. Deferasirox has shown antioxidant activity in all three model systems, causing substantial reduction in the rate of oxidation and oxidative damage. Deferasirox showed the greatest antioxidant activity in the oxidation of ascorbic acid with the participation of iron ions and reduced the reaction rate by about a 100 times. Overall, deferasirox appears to have lower affinity for copper in comparison to iron. Comparative studies of the antioxidant activity of deferasirox and the hydrophilic oral iron chelating drug deferiprone in the peroxidation of linoleic acid micelles showed lower efficiency of deferasirox in comparison to deferiprone.

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.

Renal Iron Accumulation and Oxidative Injury With Aging: Effects of Treatment With an Iron Chelator

Dysregulation of iron metabolism in the kidney may contribute to age-related increases in renal oxidative stress and dysfunction. This study assessed the effects of short-term iron chelation on markers of iron status, oxidative stress, inflammation, and autophagy in the kidneys of old rats. Old Fischer 344 rats (24 months) were treated with deferoxamine (DFO; 200 mg/kg, twice daily for 4.5 days); saline-treated young (6 months) and old rats served as controls. Renal nonheme iron was significantly higher in the old rats, with iron localized in the renal cortex. Ferritin levels were elevated in the kidneys of old rats, while expression of several antioxidant enzymes and mitochondrial proteins were reduced and protein carbonyls increased compared to young rats. DFO treatment significantly reduced ferritin levels, and increased transferrin receptor-1 protein, but did not affect nonheme iron content or protein carbonyls, nor did it reverse age-related changes in antioxidant enzymes and mitochondrial proteins. Although short-term DFO treatment did not mitigate the age-related increase in iron content and oxidative damage, this work demonstrates that old rats respond appropriately to DFO, suggesting that optimization of iron chelation regimens could be useful in improving renal homeostasis with aging.

Evidence of Renal Iron Accumulation in a Male Mouse Model of Lupus

Lupus nephritis represents a common and serious complication of the autoimmune disease Systemic Lupus Erythematosus (SLE). Clinical studies suggest that several proteins related to iron metabolism, including transferrin, serve as urinary biomarkers of lupus nephritis. We previously reported that in female NZBWF1 mice, a commonly used mouse model of SLE with a female sex bias, increased urinary transferrin excretion and renal iron accumulation occur around the onset of albuminuria. The current study investigated whether similar findings occur in male mice of a different mouse model of SLE, the MRL/lpr mouse. Two different cohorts were studied: MRL/lpr mice at an early, pre-albuminuric age (8 weeks), and after developing albuminuria (>100 mg/dL, confirmed by ELISA); age-matched MRL/MpJ control strain mice served for comparison. Urinary transferrin excretion was dramatically increased in the older, albuminuric MRL/lpr mice compared to the age-matched MRL/MpJ (P < 0.05), but there was no significant difference between strains at 8 weeks of age. Similarly, there were no significant differences between strains in renal cortical or outer medullary non-heme iron concentrations at 8 weeks. In the older, albuminuric MRL/lpr mice, renal cortical and outer medullary non-heme iron concentrations were significantly increased compared with age-matched MRL/MpJ mice, as was the expression of the iron storage protein ferritin (P < 0.01). Together, these data show that increased urinary transferrin excretion and renal tissue iron accumulation also occurs in albuminuric male MRL/lpr mice, suggesting that renal iron accumulation may be a feature of multiple mouse models of SLE.

Iron and Chelation in Biochemistry and Medicine: New Approaches to Controlling Iron Metabolism and Treating Related Diseases

Iron is essential for all living organisms. Many iron-containing proteins and metabolic pathways play a key role in almost all cellular and physiological functions. The diversity of the activity and function of iron and its associated pathologies is based on bond formation with adjacent ligands and the overall structure of the iron complex in proteins or with other biomolecules. The control of the metabolic pathways of iron absorption, utilization, recycling and excretion by iron-containing proteins ensures normal biologic and physiological activity. Abnormalities in iron-containing proteins, iron metabolic pathways and also other associated processes can lead to an array of diseases. These include iron deficiency, which affects more than a quarter of the world's population; hemoglobinopathies, which are the most common of the genetic disorders and idiopathic hemochromatosis. Iron is the most common catalyst of free radical production and oxidative stress which are implicated in tissue damage in most pathologic conditions, cancer initiation and progression, neurodegeneration and many other diseases. The interaction of iron and iron-containing proteins with dietary and xenobiotic molecules, including drugs, may affect iron metabolic and disease processes. Deferiprone, deferoxamine, deferasirox and other chelating drugs can offer therapeutic solutions for most diseases associated with iron metabolism including iron overload and deficiency, neurodegeneration and cancer, the detoxification of xenobiotic metals and most diseases associated with free radical pathology.

The History of Deferiprone (L1) and the Paradigm of the Complete Treatment of Iron Overload in Thalassaemia

Deferiprone (L1) was originally designed, synthesised and screened in vitro and in vivo in 1981 by Kontoghiorghes G. J. following his discovery of the novel alpha-ketohydroxypyridine class of iron chelators (1978–1981), which were intended for clinical use. The journey through the years for the treatment of thalassaemia with L1 has been a very difficult one with an intriguing turn of events, which continue until today. Despite many complications, such as the extensive use of L1 suboptimal dose protocols, the aim of chelation therapy-namely, the complete removal of excess iron in thalassaemia major patients, has been achieved in most cases following the introduction of specific L1 and L1/deferoxamine combinations. Many such patients continue to maintain normal iron stores. Thalassemia has changed from a fatal to chronic disease; also thanks to L1 therapy and thalassaemia patients are active professional members in all sectors of society, have their own families with children and grandchildren and their lifespan is approaching that of normal individuals. No changes in the low toxicity profile of L1 have been observed in more than 30 years of clinical use and prophylaxis against the low incidence of agranulocytosis is maintained using mandatory monitoring of weekly white blood cells’ count. Thousands of thalassaemia patients are still denied the cardioprotective and other beneficial effects of L1 therapy. The safety of L1 in thalassaemia and other non-iron loaded diseases resulted in its selection as one of the leading therapeutics for the treatment of Friedreich’s ataxia, pantothenate kinase-associated neurodegeneration and other similar cases. There are also increasing prospects for the application of L1 as a main, alternative or adjuvant therapy in many pathological conditions including cancer, infectious diseases and as a general antioxidant for diseases related to free radical pathology.

The multifaceted role of iron in renal health and disease

Iron is an essential element that is indispensable for life. The delicate physiological body iron balance is maintained by both systemic and cellular regulatory mechanisms. The iron-regulatory hormone hepcidin assures maintenance of adequate systemic iron levels and is regulated by circulating and stored iron levels, inflammation and erythropoiesis. The kidney has an important role in preventing iron loss from the body by means of reabsorption. Cellular iron levels are dependent on iron import, storage, utilization and export, which are mainly regulated by the iron response element-iron regulatory protein (IRE-IRP) system. In the kidney, iron transport mechanisms independent of the IRE-IRP system have been identified, suggesting additional mechanisms for iron handling in this organ. Yet, knowledge gaps on renal iron handling remain in terms of redundancy in transport mechanisms, the roles of the different tubular segments and related regulatory processes. Disturbances in cellular and systemic iron balance are recognized as causes and consequences of kidney injury. Consequently, iron metabolism has become a focus for novel therapeutic interventions for acute kidney injury and chronic kidney disease, which has fuelled interest in the molecular mechanisms of renal iron handling and renal injury, as well as the complex dynamics between systemic and local cellular iron regulation.

Ferritin in Kidney and Vascular Related Diseases: Novel Roles for an Old Player

Iron is at the forefront of a number of pivotal biological processes due to its ability to readily accept and donate electrons. However, this property may also catalyze the generation of free radicals with ensuing cellular and tissue toxicity. Accordingly, throughout evolution numerous pathways and proteins have evolved to minimize the potential hazardous effects of iron cations and yet allow for readily available iron cations in a wide variety of fundamental metabolic processes. One of the extensively studied proteins in the context of systemic and cellular iron metabolisms is ferritin. While clinicians utilize serum ferritin to monitor body iron stores and inflammation, it is important to note that the vast majority of ferritin is located intracellularly. Intracellular ferritin is made of two different subunits (heavy and light chain) and plays an imperative role as a safe iron depot. In the past couple of decades our understanding of ferritin biology has remarkably improved. Additionally, a significant body of evidence has emerged describing the significance of the kidney in iron trafficking and homeostasis. Here, we briefly discuss some of the most important findings that relate to the role of iron and ferritin heavy chain in the context of kidney-related diseases and, in particular, vascular calcification, which is a frequent complication of chronic kidney disease.

Precision Healthcare of Type 2 Diabetic Patients Through Implementation of Haptoglobin Genotyping

It is well-recognized that there is a need for medicine to migrate to a platform of delivering preventative care based on an individual's genetic make-up. The US National Research Council, the National Institute of Health and the American Heart Association all support the concept of utilizing genomic information to enhance the clinical management of patients. It is believed this type of precision healthcare will revolutionize health management. This current attitude of some of the most respected institutes in healthcare sets the stage for the utilization of the haptoglobin (Hp) genotype to guide precision management in type 2 diabetics (DM). There are three main Hp genotypes: 1-1, 2-1, 2-2. The Hp genotype has been studied extensively in (DM) and from the accumulated data it is clear that Hp should be considered in all DM patients as an additional independent cardiovascular disease (CVD) risk factor. In DM patients Hp2-2 generates five times increased risk of CVD compared to Hp1-1 and three times increased risk compared to Hp2-1. Data has also shown that carrying the Hp2-2 gene in DM compared to carrying an Hp1-1 genotype can increase the risk the microvascular complications of nephropathy and retinopathy. In addition, the Hp2-2 gene enhances post percutaneous coronary intervention (PCI) complications such as, in stent restenosis and need for additional revascularization during the first-year post PCI. Studies have demonstrated significant mitigation of CVD risk in Hp2-2 DM patients with administration of vitamin E and maintaining tight glycemic control. CVD is the leading cause of death and disability in DM as well-representing a huge financial burden. As such, evaluating the Hp genotype in DM patients can enhance the predictability and management of CVD risk.

Inhibition of prostate cancer proliferation by Deferiprone

Cancer growth and proliferation rely on intracellular iron availability. We studied the effects of Deferiprone (DFP), a chelator of intracellular iron, on three prostate cancer cell lines: murine, metastatic TRAMP-C2; murine, non-metastatic Myc-CaP; and human, non-metastatic 22rv1. The effects of DFP were evaluated at different cellular levels: cell culture proliferation and migration; metabolism of live cells (time-course multi-nuclear magnetic resonance spectroscopy cell perfusion studies, with 1-¹³ C-glucose, and extracellular flux analysis); and expression (Western blot) and activity of mitochondrial aconitase, an iron-dependent enzyme. The 50% and 90% inhibitory concentrations (IC₅₀ and IC₉₀ , respectively) of DFP for the three cell lines after 48 h of incubation were within the ranges 51-67 μM and 81-186 μM, respectively. Exposure to 100 μM DFP led to: (i) significant inhibition of cell migration after different exposure times, ranging from 12 h (TRAMP-C2) to 48 h (22rv1), in agreement with the respective cell doubling times; (ii) significantly decreased glucose consumption and glucose-driven tricarboxylic acid cycle activity in metastatic TRAMP-C2 cells, during the first 10 h of exposure, and impaired cellular bioenergetics and membrane phospholipid turnover after 23 h of exposure, consistent with a cytostatic effect of DFP. At this time point, all cell lines studied showed: (iii) significant decreases in mitochondrial functional parameters associated with the oxygen consumption rate, and (iv) significantly lower mitochondrial aconitase expression and activity. Our results indicate the potential of DFP to inhibit prostate cancer proliferation at clinically relevant doses and plasma concentrations.

Deferiprone attenuates inflammation and myocardial fibrosis in diabetic cardiomyopathy rats

We attempted to investigate the therapeutic effects of deferiprone on DC rats and explore the underlying mechanism. Total 24 6-week-old male Wistar rats (weighing from 180 g to 220 g) were subjected to DC model construction and then randomly divided to three groups (8 rats per group): DC group, DC + 50 mg, and DC + 100 mg deferiprone treatment group. The 8 normal rats were considered as controls. After deferiprone treatment for 20 weeks, the blood samples were collected for the biochemical parameters test, including fasting glucose, HOMA-IR (homeostasis model assessment of the insulin resistance), serum iron, ferritin and transferrin saturation (TS). The oxidative stress was assessed by detecting the level of malondialdehyde (MDA) and superoxide dismutase (SOD). Histopathologic changes were determined by Masson's trichrome staining and electron microscopy imaging. The expression levels of NF-κB (nuclear factor kappa B), COX2 (cytochrome c oxidase), tenascin C, collagen IV were measured by RT-PCR and western blotting. The expression of nitrotyrosine and MCP-1 (monocyte chemotactic protein 1) were determined by immunohistochemistry. Deferiprone treatment reduced iron deposition and IR in DC rats except for blood glucose. After deferiprone treatment, MDA level was significantly decreased and SOD level was increased significantly. The level of NF-κB, cyclooxygenase-2, tenascin C, collagen IV MCP-1 and nitrotyrosine were significantly reduced. There was no significant difference in the effect of deferiprone at 50 and 100 mg doses. Deferiprone showed therapeutic effects on DC by regulating the pro-inflammatory and pro-fibrotic factors.

Role of Haptoglobin in Health and Disease: A Focus on Diabetes

In Brief Prospective identification of individuals with diabetes who are at greatest risk for developing complications would have considerable public health importance by allowing appropriate resources to be focused on those who would benefit most from aggressive intervention. Haptoglobin (Hp) is an acute-phase protein that is crucial for the elimination of free hemoglobin and the neutralization of oxidative damage. In the past two decades, associations have been made between polymorphisms in Hp and complications arising from diabetes. Individuals with polymorphism in Hp have been shown to have significantly higher risk of developing cardiovascular disease. This review summarizes the current literature on the role of Hp in health and disease, with a focus on diabetes.

New developments and controversies in iron metabolism and iron chelation therapy

Iron is essential for all organisms including microbial, cancer and human cells. More than a quarter of the human population is affected by abnormalities of iron metabolism, mainly from iron deficiency and iron overload. Iron also plays an important role in free radical pathology and oxidative damage which is observed in almost all major diseases, cancer and ageing. New developments include the complete treatment of iron overload and reduction of morbidity and mortality in thalassaemia using deferiprone and selected deferiprone/deferoxamine combinations and also the use of the maltol iron complex in the treatment of iron deficiency anaemia. There is also a prospect of using deferiprone as a universal antioxidant in non iron overloaded diseases such as neurodegenerative, cardiovascular, renal, infectious diseases and cancer. New regulatory molecules of iron metabolism such as endogenous and dietary chelating molecules, hepcidin, mitochondrial ferritin and their role in health and disease is under evaluation. Similarly, new mechanisms of iron deposition, removal, distribution and toxicity have been identified using new techniques such as magnetic resonance imaging increasing our understanding of iron metabolic processes and the targeted treatment of related diseases. The uniform distribution of iron in iron overload between organs and within each organ is no longer valid. Several other controversies such as the toxicity impact of non transferrin bound iron vs injected iron, the excess levels of iron in tissues causing toxicity and the role of chelation on iron absorption need further investigation. Commercial interests of pharmaceutical companies and connections to leading journals are playing a crucial role in shaping worldwide medical opinion on drug sales and use but also patients' therapeutic outcome and safety. Major controversies include the selection criteria and risk/benefit assessment in the use of deferasirox in thalassaemia and more so in idiopathic haemochromatosis, thalassaemia intermedia and ex-thalassaemia transplanted patients who are safely treated with venesection. Iron chelating drugs can override normal regulatory pathways, correct iron imbalance and minimise iron toxicity. The use of iron chelating drugs as main, alternative or adjuvant therapy is in progress in many conditions, especially those with non established or effective therapies.

Efficacy and safety of iron-chelation therapy with deferoxamine, deferiprone, and deferasirox for the treatment of iron-loaded patients with non-transfusion-dependent thalassemia syndromes

The prevalence rate of thalassemia, which is endemic in Southeast Asia, the Middle East, and the Mediterranean, exceeds 100,000 live births per year. There are many genetic variants in thalassemia with different pathological severity, ranging from a mild and asymptomatic anemia to life-threatening clinical effects, requiring lifelong treatment, such as regular transfusions in thalassemia major (TM). Some of the thalassemias are non-transfusion-dependent, including many thalassemia intermedia (TI) variants, where iron overload is caused by chronic increase in iron absorption due to ineffective erythropoiesis. Many TI patients receive occasional transfusions. The rate of iron overloading in TI is much slower in comparison to TM patients. Iron toxicity in TI is usually manifested by the age of 30-40 years, and in TM by the age of 10 years. Subcutaneous deferoxamine (DFO), oral deferiprone (L1), and DFO-L1 combinations have been effectively used for more than 20 years for the treatment of iron overload in TM and TI patients, causing a significant reduction in morbidity and mortality. Selected protocols using DFO, L1, and their combination can be designed for personalized chelation therapy in TI, which can effectively and safely remove all the excess toxic iron and prevent cardiac, liver, and other organ damage. Both L1 and DF could also prevent iron absorption. The new oral chelator deferasirox (DFX) increases iron excretion and decreases liver iron in TM and TI. There are drawbacks in the use of DFX in TI, such as limitations related to dose, toxicity, and cost, iron load of the patients, and ineffective removal of excess iron from the heart. Furthermore, DFX appears to increase iron and other toxic metal absorption. Future treatments of TI and related iron-loading conditions could involve the use of the iron-chelating drugs and other drug combinations not only for increasing iron excretion but also for preventing iron absorption.

Phytochelators Intended for Clinical Use in Iron Overload, Other Diseases of Iron Imbalance and Free Radical Pathology

Iron chelating drugs are primarily and widely used in the treatment of transfusional iron overload in thalassaemia and similar conditions. Recent in vivo and clinical studies have also shown that chelators, and in particular deferiprone, can be used effectively in many conditions involving free radical damage and pathology including neurodegenerative, renal, hepatic, cardiac conditions and cancer. Many classes of phytochelators (Greek: phyto (φυτό)—plant, chele (χηλή)—claw of the crab) with differing chelating properties, including plant polyphenols resembling chelating drugs, can be developed for clinical use. The phytochelators mimosine and tropolone have been identified to be orally active and effective in animal models for the treatment of iron overload and maltol for the treatment of iron deficiency anaemia. Many critical parameters are required for the development of phytochelators for clinical use including the characterization of the therapeutic targets, ADMET, identification of the therapeutic index and risk/benefit assessment by comparison to existing therapies. Phytochelators can be developed and used as main, alternative or adjuvant therapies including combination therapies with synthetic chelators for synergistic and or complimentary therapeutic effects. The development of phytochelators is a challenging area for the introduction of new pharmaceuticals which can be used in many diseases and also in ageing. The commercial and other considerations for such development have great advantages in comparison to synthetic drugs and could also benefit millions of patients in developing countries.

Association between renal iron accumulation and renal interstitial fibrosis in a rat model of chronic kidney disease

Iron accumulation is associated with the pathophysiology of chronic kidney disease (CKD). Renal fibrosis is a final common feature that contributes to the progression of CKD; however, little is known about the association between renal iron accumulation and renal interstitial fibrosis in CKD. Here we investigate the effects of iron chelation on renal interstitial fibrosis in a rat model of CKD. CKD was induced by 5/6 nephrectomy in Sprague-Dawley rats. At 8 weeks after operation, 5/6 nephrectomized rats were administered an oral iron chelator, deferasirox (DFX), in chow for 8 weeks. Other CKD rats were given a normal diet. Sham-operative rats given a normal diet served as a control. CKD rats exhibited hypertension, glomerulosclerosis and renal interstitial fibrosis. Iron chelation with DFX did not change hypertension and glomerulosclerosis; however, renal interstitial fibrosis was attenuated in CKD rats. Consistent with these findings, renal gene expression of collagen type III and transforming growth factor-β was increased in CKD rats compared with the controls, while iron chelation suppressed these increments. In addition, a decrease in vimentin along an increase in E-cadherin in renal gene expression was observed in CKD rats with iron chelation. CKD rats also showed increased CD68-positive cells in the kidney, whereas its increase was attenuated by iron deprivation. Similarly, increased renal gene expression of CD68, tumor necrosis factor-α and monocyte chemoattractant protein-1 was suppressed in CKD rats with iron chelation. Renal iron accumulation seems to be associated with renal interstitial fibrosis in a rat model of CKD.

Transition of Thalassaemia and Friedreich ataxia from fatal to chronic diseases

Thalassaemia major (TM) and Friedreich’s ataxia (FA) are autosomal recessive inherited diseases related to the proteins haemoglobin and frataxin respectively. In both diseases abnormalities in iron metabolism is the main cause of iron toxicity leading to increased morbidity and mortality. Major efforts are directed towards the prevention of these diseases and also in their treatment using iron chelation therapy. Both TM and FA are endemic in Cyprus, where the frequency per total population of asymptomatic heterozygote carriers and patients is the highest worldwide. Cyprus has been a pioneering nation in preventing and nearly eliminating the birth of TM and FA patients by introducing an organized health structure, including prenatal and antenatal diagnosis. Effective iron chelation therapy, improved diagnostic methods and transfusion techniques as well as supportive therapy from other clinical specializations have improved the survival and quality of life of TM patients. Despite the tiresome clinical management regimes many TM patients are successful in their professional lives, have families with children and some are now living well into their fifties. The introduction of deferiprone led to the elimination of cardiac failure induced by iron overload toxicity, which was the major cause of mortality in TM. Effective combinations of deferiprone with deferoxamine in TM patients caused the fall of body iron to normal physiological ranges. In FA different mechanisms of iron metabolism and toxicity apply to that of TM, which can be targeted with specific iron chelation protocols. Preliminary findings from the introduction of deferiprone in FA patients have increased the hopes for improved and effective therapy in this untreatable condition. New and personalised treatments are proposed in TM and FA. Overall, advances in treatments and in particular of chelation therapy using deferiprone are transforming TM and FA from fatal to chronic conditions. The paradigm of Cyprus in the prevention and treatment of TM can be used for application worldwide.

World health dilemmas: Orphan and rare diseases, orphan drugs and orphan patients

According to global annual estimates hunger/malnutrition is the major cause of death (36 of 62 million). Cardiovascular diseases and cancer (5.44 of 13.43 million) are the major causes of death in developed countries, while lower respiratory tract infections, human immunodeficiency virus infection/acquired immunodeficiency syndrome, diarrhoeal disease, malaria and tuberculosis (10.88 of 27.12 million) are the major causes of death in developing countries with more than 70% of deaths occurring in children. The majority of approximately 800 million people with other rare diseases, including 100000 children born with thalassaemia annually receive no treatment. There are major ethical dilemmas in dealing with global health issues such as poverty and the treatment of orphan and rare diseases. Of approximately 50000 drugs about 10% are orphan drugs, with annual sales of the latter approaching 100 billion USD. In comparison, the annual revenue in 2009 from the top 12 pharmaceutical companies in Western countries was 445 billion USD and the top drug, atorvastatin, reached 100 billion USD. In the same year, the total government expenditure for health in the developing countries was 410 billion USD with only 6%-7% having been received as aid from developed countries. Drugs cost the National Health Service in the United Kingdom more than 20 billion USD or 10% of the annual health budget. Uncontrollable drug prices and marketing policies affect global health budgets, clinical practice, patient safety and survival. Fines of 5.3 billion USD were imposed on two pharmaceutical companies in the United States, the regulatory authority in France was replaced and clinicians were charged with bribery in order to overcome recent illegal practises affecting patient care. High expenditure for drug development is mainly related to marketing costs. However, only 2 million USD was spent developing the drug deferiprone (L1) for thalassaemia up to the stage of multicentre clinical trials. The criteria for drug development, price levels and use needs to be readdressed to improve drug safety and minimise costs. New global health policies based on cheaper drugs can help the treatment of many categories of orphan and rare diseases and millions of orphan patients in developing and developed countries.

Effects of iron overload on chronic metabolic diseases

Iron can affect the clinical course of several chronic metabolic diseases such as type 2 diabetes, obesity, non-alcoholic fatty liver disease, and atherosclerosis. Iron overload can affect major tissues involved in glucose and lipid metabolism (pancreatic β cells, liver, muscle, and adipose tissue) and organs affected by chronic diabetic complications. Because iron is a potent pro-oxidant, fine-tuned control mechanisms have evolved to regulate entry, recycling, and loss of body iron. These mechanisms include the interplay of iron with transferrin, ferritin, insulin, and hepcidin, as well as with adipokines and proinflammatory molecules. An imbalance of these homoeostatic mechanisms results in systemic and parenchymal siderosis that contributes to organ damage (such as β-cell dysfunction, fibrosis in liver diseases, and atherosclerotic plaque growth and instability). Conversely, iron depletion can exert beneficial effects in patients with iron overload and even in healthy frequent blood donors. Regular assessment of iron balance should be recommended for patients with chronic metabolic diseases, and further research is needed to produce guidelines for the identification of patients who would benefit from iron depletion.

Potential clinical applications of chelating drugs in diseases targeting transferrin-bound iron and other metals

INTRODUCTION

Iron is essential for normal, neoplasmic and microbial cells. Transferrin (Tf) is responsible for iron transport and its interactions with chelators are of physiological and toxicological importance and could lead to new therapeutic applications.

AREAS COVERED

Differential interactions of Tf with chelators such as deferiprone (L1) could be used to modify toxicity and disease pathways in relation to iron and other metal metabolism. Iron mobilization by L1 could achieve normal body iron stores in thalassemia patients. Iron mobilization from the reticuloendothelial system by L1 and exchange with Tf could be used to increase the production of hemoglobin in the anemia of chronic disease. Iron accumulation is pathogenic in neurodegenerative, acute kidney and other diseases and could be removed by L1 with therapeutic implications. Deprivation of iron from neoplasmic and microbial cells by chelators could increase the prospect of improved treatments in cancer and infectious diseases. Other applications include metal detoxification and inhibition of oxidative stress-related conditions.

EXPERT OPINION

Specific mechanisms apply in the interactions of chelators with Tf, which could be used in the design of targeted therapeutic strategies in many conditions. In each case specific chelator protocols have to be designed for achieving optimum therapeutic activity.