Brain Iron Overload Research Articles

Aceruloplasminemia: MRI and Biochemical Profile Clue to Early Diagnosis in an Adolescent

AbstractAceruloplasminemia (ACP) is a rare autosomal recessive genetic disorder with systemic and brain iron overload, secondary to ceruloplasmin gene mutation, usually presents in adults with neurological manifestations. An abnormal biochemical profile may be the only clue in an adolescent patient, that is, microcytic anemia, low transferrin saturation, hyperferritinemia, and should warrant a possible diagnosis of ACP, which can be established by low serum ceruloplasmin levels and appropriate genetic testing. We present a case of an adolescent patient in whom ACP was suspected when brain magnetic resonance imaging showed iron overload in basal ganglia, thalami, red nuclei, dentate nuclei, and choroid plexus and later on confirmed by biochemical profile. The final diagnosis was confirmed by the presences of a novel mutation on genetic analysis. To the best of our knowledge, our case is the second description of ACP with choroid plexus hemosiderosis.We proposed in this article that the combination of parenchymal and choroid plexus iron overload should prompt the suspicion of ACP.

Non-invasive Quantitative MRI assessment of brain iron overload in patients with BThalassemia and Sickle cell disease

Abstract Background B-Thalassemia, sickle cell disease (SCD) and other inherited hemoglobin disorders are considered the most prevalent monogenic diseases worldwide. Secondary iron overload is one of the major complications in such groups of patients affecting many organs (e.g. liver, heart and endocrinal glands). Objective The current study will assess brain iron content ( using R2* values ) in the caudate and thalamic regions through quantitative brain MRI study in B-Thalassemia and SCD patients in comparison to age and sex-matched healthy controls. Also evaluation of the association with LIC (liver iron concentrations) and MIC (myocardial iron concentrations) was done. Methods A case control study on 30 patients (15 with B-thalassemia major and 15 with SCD) and 11 age and sex-matched healthy controls was carried out in the period between August 2018 till August 2019. Brain MRI study using multiecho fast gradient echo sequence was done for all the patients and controls. Brain R2* values of both caudate and thalamic regions (right and left sides) were calculated. Also brain R2* values were correlated with the LIC and HIC in B-thalassemia and SCD groups. Results 15 transfusion dependent B-thalassemia (mean-age: 19.40 ± 4.31 years, 53.3% females), 15 SCD patients (SCD; mean-age: 16.93 ± 3.41 years, 40.6% females) and 11 age and sex matched healthy controls (HC; mean age: 18.73 ± 4.84 years, 54.5% females) were enrolled in the study. No statistically significant differences were found between SCD and control group in all regions of interests No statistically significant differences were found between the three subgroups (p > 0.05) in right thalamus, left and right caudate regions. However, in B-thalassemia subgroup, patients had moderately significantly higher R2* values compared to the controls and SCD patients as regards the left thalamic region with mean R2* values (16.69 ± 1.34) Hz compared to (15.65 ± 1.10) Hz in the control group (p = 0.021) and (15.79 ± 0.77) Hz in the SCD group (p = 0.029). There were no significant correlations between LIC and HIC with brain R2* values of all regions of interests in both B-thalassemia and SCD subgroups. Conclusion MRI is a valuable, reliable, safe and noninvasive method for quantifying iron concentration (in cases of iron overload) in many organs as the liver and heart and it is now used internationally for regular follow up of LIC and HIC for monitoring of the chelation therapy in B-thalassemia and SCD patients. The results of our study showed that even in cases of iron overload which affects vital organs as the liver, cardiac and brain iron overload don't occur. This may be explained by heavy chelation therapy regimens given to our patients due to their poor compliance so as to keep the pre-transfusion hemoglobin level above 10mg/dl to prevent detrimental cardiac affection as cardiac siderosis, arrhythmias including heart block, or even heart failure.

Aceruloplasminemia: A novel splicing mutation preserving the globus pallidus from Iron accumulation

Hereditary aceruloplasminemia (HA) is a rare inherited disease caused by homozygous mutation of ceruloplasmin (CP) gene, characterized by brain iron overload. Hypointensity of MRI signal in thalami and basal ganglia, especially globus pallidus (GP) is considered a neuroimaging hallmark of this disease. Here, we report the case of two Italian cousins carrying a novel splicing homozygous mutation in intron 6 (IVS6 + 1 G > A) of CP gene.

Evaluation of brain iron content in Egyptian Patients with Sickle cell disease and its impact on Neurocognitive functions

Abstract Background Sickle cell disease (SCD) is considered the most prevalent monogenic diseases worldwide. Iron overload is one of the major complications in those patients, especially who in need for frequent transfusion, affecting many organs including the brain. MRI is a valuable, reliable and non-invasive method for quantifying iron concentration in many organs as the liver and heart and it is now used for monitoring of the chelation therapy in SCD patients. Several studies began reporting differences in global cognitive function, particularly for children with SCD, they are at a high risk for neurocognitive impairment they often scored lower on general IQ measures than healthy children which is due to iron overload in brain tissue from the chronic transfusions which can lead to strokes and may be a silent stroke. Objective The current study assessed brain iron content (using R2* values) in the caudate and thalamic regions through quantitative brain MRI study in SCD patients in comparison to age and sex-matched healthy controls. Methods A case-control study recruited 32 patients with SCD and 11 healthy controls. Brain MRI study using multi-echo fast gradient echo sequence was done for all the patients and controls. Brain R2* values of both caudate and thalamic regions (right and left sides) were calculated for only 15 SCD patients and the 11 controls. All recruited SCD patients and controls were examined for the neurocognitive functions by these tests: Wechsler IV Intelligence Scale for Adult shows (Verbal, Perceptual, Memory, Processing and Total IQ), their all normal values between 90 – 110. Benton Visual Retention Test have cut of point at (> 4 or = 4). Those values are the same for the difference between the obtained correct and the expected correct, and the difference between the obtained error and expected error. Results The fifteen patient with SCD who underwent brain MRI were age and sex matched with the eleven healthy control (15 SCD patients: mean-age: 16.93 ± 3.41 years, 40.6% females and 11healthy controls: mean age: 18.73 ± 4.84 years, 54.5% females) were enrolled in the study. As regards the brain MRI, there was no statistically significant differences between SCD and control group in all regions of interests (p > 0.05). Our study showed that 72.7% of our SCD patients had under threshold TIQ scores. Also18% of the patients showed moderate anxiety, 9% mild anxiety and 9% showed severe anxiety. Conclusion The results of our study showed that even in cases of iron overload which affects vital organs as the liver, cardiac and brain iron overload don't occur.

Hidden brain iron content in sickle cell disease: impact on neurocognitive functions

Children with sickle cell disease (SCD) are at a high risk for neurocognitive impairment. We aim to quantitatively measure cerebral tissue R2* to investigate the brain iron deposition in children and young adults with SCD in comparison to beta thalassemia major (BTM) and healthy controls and evaluate its impact on neurocognitive functions in patients with SCD. Thirty-two SCD, fifteen BTM, and eleven controls were recruited. Multi-echo fast-gradient echo sequence brain MRI was performed, and brain R2* values of both caudate and thalamic regions were calculated. SCD patients were examined for the neurocognitive functions. SCD had high iron overload 0.30 ± 0.12mg/kg/day. 68.9% of SCD had under-threshold IQ, 12.5% had moderate to severe anxiety, and 60.8% had depression. There were no differences between SCD, BTM, and controls in brain MRI except that left thalamus R2* higher in BTM than both SCD and controls (p = 0.032). Mean right caudate R2* was higher in female than male (p = 0.044). No significant association between brain R2* and LIC or heart R2* values in SCD. Left caudate R2* directly correlate with age and HbS%, and negatively correlate with HbA% while right thalamus R2* negatively correlate with transfusion index and among SCD patients.Conclusion: Neurocognitive dysfunction in SCD could not be explained solely by brain iron overload. What is Known: • Children with sickle cell disease are at great risk of brain damage due to their irregularly shaped red blood cells that can interrupt blood flow to the brain. • There are a number of factors that have negative brain effects that result in learning difficulties, and this not only due to increase brain iron content. What is New: • Assessment of quantitative brain iron content using MRI R2* in children and young adults with SCD in comparison to beta thalassemia major and healthy controls. • Impact of brain iron content on neurocognitive functions of children and young adults with SCD.

The Effect of TCM-Induced HAMP on Key Enzymes in the Hydrolysis of AD Model Cells.

Alzheimer's disease (AD) process is characterized classically by two hallmark pathologies: β-amyloid (Aβ) plaque deposition and neurofibrillary tangles of hyperphosphorylated tau. Aβ peptides play an important role in AD, but despite much effort the molecular mechanisms of how Aβ contributes to AD remain unclear. The present study evaluated the effects of the active components of Epimedium, Astragalus and Radix Puerariae induced HAMP on key enzymes in the hydrolysis of APP in HT22 cells. The active components of Epimedium, Astragalus and Radix Puerariae could effectively up-regulate the expression of HAMP, alleviate the iron overload in the brain tissues of mice, significantly improve the learning and memory ability of AD, down-regulate the expression of Aβ and reduce the deposition of SP in an APPswe/PS1ΔE9 transgenic mouse model of AD. HAMP and Aβ25-35 induced HT22 cells are used as AD cell models in this study to investigate the effect of the compound consisting of the effective components of Epimedium, Astragalus and Pueraria on the key enzymes in the hydrolysis of APP. After the administration of traditional Chinese medicine (TCM), the expression levels of ADAM10 and ADAM17 were increased while the expression level of BACE1 decreased. This indicates that TCM can promote the expression level of ADAM10 and ADAM17, inhibit the expression level of BACE1, thus further inhibiting the production of amyloid protein and reducing the production of Aβ and SP. Compared with RNAi group, the expression level of ADAM10 and ADAM17 in Aβ + RNAi group was decreased while the expression level of BACE1 increased. Compared with the Aβ + RNAi group the expression level of ADAM10 and ADAM17 in the Aβ + RNAi + TCM group was increased while the expression level of BACE1 was decreased. The present study indicated the effects of the active components of Epimedium, Astragalus and Radix Puerariae may alleviate AD by up-regulating the expression of HAMP, thus reducing brain iron overload, promoting the expression of ADAM10 and ADAM17, inhibiting the expression of BACE1, and reducing the deposition of Aβ.

Elevated neuroinflammation contributes to the deleterious impact of iron overload on brain function in aging

Intracellular iron is essential for many neurobiological mechanisms. However, at high concentrations, iron may induce oxidative stress and inflammation. Brain iron overload has been shown in various neurodegenerative disorders and in normal aging. Elevated brain iron in old age may trigger brain dysfunction and concomitant cognitive decline. However, the exact mechanism underlying the deleterious impact of iron on brain function in aging is unknown. Here, we investigated the role of iron on brain function across the adult lifespan from 187 healthy participants (20–79 years old, 99 women) who underwent fMRI scanning while performing a working-memory n-back task. Iron content was quantified using R2* relaxometry, whereas neuroinflammation was estimated using myo-inositol measured by magnetic resonance spectroscopy. Striatal iron increased non-linearly with age, with linear increases at both ends of adulthood. Whereas higher frontostriatal activity was related to better memory performance independent of age, the link between brain activity and iron differed across age groups. Higher striatal iron was linked to greater frontostriatal activity in younger, but reduced activity in older adults. Further mediation analysis revealed that, after age 40, iron provided unique and shared contributions with neuroinflammation to brain activations, such that neuroinflammation partly mediated brain-iron associations. These findings promote a novel mechanistic understanding of how iron may exert deleterious effects on brain function and cognition with advancing age.

Association of Brain Iron Overload With Brain Edema and Brain Atrophy After Intracerebral Hemorrhage.

Objective: This study evaluated iron overload after intracerebral hemorrhage (ICH) using ESWAN sequences.Methods: This single-center prospective observational cohort study enrolled supratentorial ICH patients. MRI was obtained with a 3.0-T scanner at day 1, day 14, day 30, and follow-up (300 days or later). R2* mapping was generated based on the ESWAN. R2* value of the ipsilateral side represented iron deposition, and the R2* value of the contralateral side served as control. R2* value was adjusted by volume and used to assess total iron overload. Brain edema was measured on T2 FLAIR-weighted images. Brain atrophy was calculated as the contralateral hemisphere volume minus the injured hemisphere volume.Results: Twnety-seven patients with a spontaneous supratentorial ICH were included in this analysis. The ipsilateral R2* value was 40.27 ± 11.62, 41.92 ± 13.56, and 60.89 ± 14.09 at days 1, 14, and 30, respectively. The R2* value was significantly higher in the ICH side than the contralateral side (p < 0.01). Increased R2* value was seen on day 30 compared to day 14 (p < 0.01). The R2* value showed logistic decay with the distance to the hematoma margin (p < 0.01). Brain edema at day 14 and brain atrophy at follow-up correlated with R2* value adjusted by volume at day 14 (p < 0.01).Conclusions: After ICH, the iron deposition in the perihematomal region was progressively increased during the first month. R2* value adjusted by volume predicted acute brain edema and chronic brain atrophy.

Does thiamine protect the brain from iron overload and alcohol-related dementia?

Alcohol‐related dementia (ARD) is a common and severe co‐morbidity in alcohol use disorder (AUD). We propose brain iron overload (BIO) to be an important and previously neglected pathogenic process, accelerating cognitive decline in AUD. Furthermore, we suggest thiamine, which is frequently depleted in AUD, to be a key modulator in this process: Thiamine deficiency impairs the integrity of the blood‐brain barrier, thereby enabling iron to pass through and accumulate in the brain. This hypothesis is based on findings from animal, translational, and neuroimaging studies, discussed in this article. To validate this hypothesis, translational studies focusing on brain iron homeostasis in AUD, as well as prospective clinical studies investigating prevalence and clinical impact of BIO in AUD, should be conducted. If proven right, this would change the understanding of ARD and may lead to novel therapeutic interventions in prevention and treatment of ARD.

WDR45 Contributes to Iron Accumulation Through Dysregulation of Neuronal Iron Homeostasis

Abstract Objectives Neurodegeneration with brain iron accumulation (NBIA) is a clinically and genetically heterogeneous group of neurodegenerative diseases characterized by an abnormal accumulation of brain iron and progressive degeneration of the nervous system. β-propeller protein-associated neurodegeneration (BPAN) (OMIM #300,894) is a recently identified subtype of NBIA. BPAN is caused by de novo mutations in the WD repeat domain 45 (WDR45) gene. WDR45 deficiency in BPAN patients and animal models has shown defects in autophagic flux, suggesting a role for WDR45 in autophagy. How WDR45 deficiency leads to brain iron overload remains unclear. The goal of the present study is to identify the pathogenic mechanisms of WDR45 deficiency that cause iron overload and neurodegeneration. Methods To elucidate the role of WDR45 in dopaminergic neuronal cells, we generated a WDR45-knockout (KO) SH-SY5Y cell line by CRISPR/Cas9-mediated genome editing. To identify mechanisms underlying iron homeostasis and transport, we examined two cellular iron acquisition pathways in these cells using radioactive isotope 59Fe: 1) the canonical transferrin-bound iron (TBI) uptake pathway and 2) the nontransferrin-bound iron (NTBI) pathway. Results Loss of WDR45 increased total iron levels with a concomitant increase in the iron storage protein ferritin in neuronal cells. Specifically, WDR45-KO cells preferentially took up NTBI compared to wild-type cells. Concordant with these functional data, the level of divalent metal transporter-1 (DMT1) expression was upregulated in WDR45-KO cells, providing a causal link to iron overload in WDR45 deficiency. In addition, loss of WDR45 led to defects in autophagic flux and impaired ferritinophagy, a lysosomal process that promotes ferritin degradation, suggesting that iron overload is driven by impaired ferritinophagy. Interestingly, WDR45 deficiency increased iron accumulation in the mitochondria, impaired mitochondrial function, and in turn, elevated reactive oxygen species generation. Conclusions Our study provides the first evidence that WDR45 deficiency alters cellular iron acquisition pathways thereby leading to iron accumulation in neuronal cells. These findings will serve as a basis for developing therapeutic strategies for patients with NBIA. Funding Sources NIH, NBIA Disorder Association.

Huperzine A, reduces brain iron overload and alleviates cognitive deficit in mice exposed to chronic intermittent hypoxia

Chronic intermittent hypoxia (CIH) is a consequence of obstructive sleep apnea (OSA), which increases reactive oxygen species (ROS) generation, resulting in oxidative damage and neurocognitive impairment. This study was designed to determine whether abnormal iron metabolism occurs in the brain under conditions of CIH and whether Huperzine A (HuA) could improve abnormal iron metabolism and neurological damage. The mouse model of CIH was established by reducing the percentage of inspired O2 (FiO2) from 21% to 9% 20 times/h for 8 h/day, and Huperzine A (HuA, 0.1 mg/kg, i.p.) was administered during CIH exposure for 21 days. HuA significantly improved cognitive impairment and neuronal damage in the hippocampus of CIH mice via increasing the ratio of Bcl-2/Bax and inhibiting caspase-3 cleavage. HuA considerably decreased ROS levels by downregulating the high levels of NADPH oxidase (NOX 2, NOX 4) mediated by CIH. There was an overload of iron, which was characterized by high levels of ferritin (FTL and FTH) and transferrin receptor 1 (TfR1) and low levels of ferroportin 1 (FPN1) in the hippocampus of CIH mice. Decreased levels of TfR1 and FTL proteins observed in HuA treated CIH group, could reduce iron overload in hippocampus. HuA increased PSD 95 protein expression, CREB activation and BDNF protein expression to protect against synaptic plasticity impairment induced by CIH. HuA acts as an effective iron chelator to attenuate apoptosis, oxidative stress and synaptic plasticity mediated by CIH.

Iron chelation by deferiprone does not rescue the Niemann-Pick Disease Type C1 mouse model.

Niemann-Pick Disease Type C (NP-C) is a fatal lysosomal storage disorder with progressive neurodegeneration. In addition to the characteristic cholesterol and lipid overload phenotype, we previously found that altered metal homeostasis is also a pathological feature. Increased brain iron in the Npc1-/- mouse model of NP-C may potentially contribute to neurodegeneration, similar to neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Deferiprone (DFP) is a brain penetrating iron chelator that has demonstrated effectiveness in preventing neurological deterioration in Parkinson's disease clinical trials. Therefore, we hypothesized that DFP treatment, targeting brain iron overload, may have therapeutic benefits for NP-C. Npc1-/- mice were assigned to four experimental groups: (1) pre-symptomatic (P15) + 75 mg/kg DFP; (2) pre-symptomatic (P15) + 150 mg/kg DFP; (3) symptomatic (P49) + 75 mg/kg DFP; (4) symptomatic (P49) + 150 mg/kg DFP. Our study found that in Npc1-/- mice, DFP treatment did not offer any improvement over the expected disease trajectory and median lifespan. Moreover, earlier treatment and higher dose of DFP resulted in adverse effects on body weight and onset of ataxia. The outcome of our study indicated that, despite increased brain iron, Npc1-/- mice were vulnerable to pharmacological iron depletion, especially in early life. Therefore, based on the current model, iron chelation therapy is not a suitable treatment option for NP-C.

Iron Metabolism, Ferroptosis, and the Links With Alzheimer's Disease.

Iron is an essential transition metal for numerous biologic processes in mammals. Iron metabolism is regulated via several coordination mechanisms including absorption, utilization, recycling, and storage. Iron dyshomeostasis can result in intracellular iron retention, thereby damaging cells, tissues, and organs through free oxygen radical generation. Numerous studies have shown that brain iron overload is involved in the pathological mechanism of neurodegenerative disease including Alzheimer’s disease (AD). However, the underlying mechanisms have not been fully elucidated. Ferroptosis, a newly defined iron-dependent form of cell death, which is distinct from apoptosis, necrosis, autophagy, and other forms of cell death, may provide us a new viewpoint. Here, we set out to summarize the current knowledge of iron metabolism and ferroptosis, and review the contributions of iron and ferroptosis to AD.

Deferiprone and efonidipine mitigated iron-overload induced neurotoxicity in wild-type and thalassemic mice

AimsWe previously demonstrated that iron-overload in non-thalassemic rats induced neurotoxicity and cognitive decline. However, the effect of iron-overload on the brain of thalassemic condition has never been investigated. An iron chelator (deferiprone) provides neuroprotective effects against metal toxicity. Furthermore, a T-type calcium channels blocker (efonidipine) effectively attenuates cardiac dysfunction in thalassemic mice with iron-overload. However, the effects of both drugs on brain of iron-overload thalassemia has not been determined. We hypothesize that iron-overload induces neurotoxicity in Thalassemic and wild-type mice, and not only deferiprone, but also efonidipine, provides neuroprotection against iron-overload condition. Main methodsMice from both wild-type (WT) and β-thalassemic type (HT) groups were assigned to be fed with a standard-diet or high-iron diet containing 0.2% ferrocene/kg of diet (HFe) for 4 months consecutively. After three months of HFe, 75-mg/kg/d deferiprone or 4-mg/kg/d efonidipine were administered to the HFe-fed WT and HT mice for 1 month. Key findingsHFe consumption caused an equal impact on circulating iron-overload, oxidative stress, and inflammation in WT and HT mice. Brain iron-overload and iron-mediated neurotoxicity, such as oxidative stress, inflammation, glial activation, mitochondrial dysfunction, and Alzheimer's like pathologies, were observed to an equal degree in HFe fed WT and HT mice. These pathological conditions were mitigated by both deferiprone and efonidipine. SignificanceThese findings indicate that iron-overload itself caused neurotoxicity, and T-type calcium channels may play a role in this condition.

Airborne Magnetite- and Iron-Rich Pollution Nanoparticles: Potential Neurotoxicants and Environmental Risk Factors for Neurodegenerative Disease, Including Alzheimer's Disease.

Fewer than 5% of Alzheimer's disease (AD) cases are demonstrably directly inherited, indicating that environmental factors may be important in initiating and/or promoting the disease. Excess iron is toxic to cells; iron overload in the AD brain may aggressively accelerate AD. Magnetite nanoparticles, capable of catalyzing formation of reactive oxygen species, occur in AD plaques and tangles; they are thought to form in situ, from pathological iron dysfunction. A recent study has identified in frontal cortex samples the abundant presence of magnetite nanoparticles consistent with high-temperature formation; identifying therefore their external, not internal source. These magnetite particles range from ∼10 to 150 nm in size, and are often associated with other, non-endogenous metals (including platinum, cadmium, cerium). Some display rounded crystal morphologies and fused surface textures, reflecting cooling and crystallization from an initially heated, iron-bearing source material. Precisely-matching magnetite 'nanospheres' occur abundantly in roadside air pollution, arising from vehicle combustion and, especially, frictional brake-wear. Airborne magnetite pollution particles < ∼200 nm in size can access the brain directly via the olfactory and/or trigeminal nerves, bypassing the blood-brain barrier. Given their toxicity, abundance in roadside air, and nanoscale dimensions, traffic-derived magnetite pollution nanoparticles may constitute a chronic and pernicious neurotoxicant, and hence an environmental risk factor for AD, for large population numbers globally. Olfactory nerve damage displays strong association with AD development. Reported links between AD and occupational magnetic fields (e.g., affecting welders, machinists) may instead reflect inhalation exposure to airborne magnetic nanoparticles.

Iron in Health and Disease: An Update.

Iron is an essential micronutrient for oxygen transport, cellular energy metabolism, and manyenzymatic reactions. Complex physiological processes have evolved for iron acquisition to meet metabolic needs while avoidingtoxicity from iron-generated free radicals. Systemic iron homeostasis is centered around the regulation of iron absorption from duodenum and ironrelease from stores by hepcidin. Intracellular iron is maintained under tight controlby ironregulatory proteinsacting atpost-transcriptional level. Despitethese elaborate mechanisms, iron status is frequentlyaltered by environmental or genetic influences. Iron deficiencyanemia is the most common nutritional disorder affecting a quarter of the world population. Iron deficiency is associated with impaired cognitive development and reduced capacity for physical work, makingit a high priority for public health initiatives. Chronic inflammation from infections or other causes limits iron availability and contributes to anemia of chronic disease. At the opposite end are conditions where iron overloadleads toserious complications from organ damage. Mutations in HFEgene are the most frequent cause of hereditary hemochromatosis in European population, but rare elsewhere in the world. Iron overload develops in dyserythropoieticanemias fromincreasedintestinal absorption. Transfusional iron overload, most often observed in thalassemia, is increasing amongcancer survivors due to the use of protocolsrequiring intensive transfusion support. Tissue-specific brain iron overload is observed in somedegenerative neurologicaldiseaseswithout an increase in systemic iron. New insights into iron metabolism are guiding the development of novel therapies for iron deficiency and iron overload.

MRI imaging and histopathological study of brain iron overload of β-thalassemic mice

Brain iron overload is chronic and slow progressing and plays an important role in the pathogenesis of neurodegenerative disorders. Magnetic resonance imaging (MRI) is a useful noninvasive tool for determining liver iron content, but it has not been proven to be adequate for evaluating brain iron overload. We evaluated the usefulness of MRI-derived parameters to determine brain iron concentration in β-thalassemic mice and the effects of the membrane permeable iron chelator, deferiprone. Sixteen β-thalassemic mice underwent 1.5T MRI of the brain that included a multiecho T2*-weighted sequence. Brain T2* values ranged from 28 to 31ms for thalassemic mice. For the iron overloaded thalassemic mice, brain T2* values decreased, ranging from 8 to 12ms, which correlated with the iron overload status of the animals. In addition, brain T2* values increased in the group with the treatment of deferiprone, ranging from 18 to 24ms. Our results may be useful to understand brain pathology in iron overload. Moreover, data could lead to an earlier diagnosis, assist in following disease progression, and demonstrate the benefits of iron chelation therapy.

Iron Pathophysiology in Neurodegeneration with Brain Iron Accumulation.

Neurodegeneration with brain iron accumulation (NBIA) is a group of seriously devastating and life-threatening rare monogenic diseases characterized by focal iron accumulation in the brain. The main symptoms of NBIA comprise progressive movement disorder, often including painful dystonia, parkinsonism, mental disability, and early death. Currently, a single established therapy is not available to reverse the progression of these debilitating disorders. The complexity of NBIA emerged from the identification of various causative genes, and up to 15 genes have been identified to date. Although the NBIA genes are involved in different cellular biochemical pathways, they show the common characteristic of generating severe iron accumulation in the basal ganglia of the patients' brains. Thus, the molecular events that lead to brain iron overload and their important roles in the pathophysiology of the diseases are not easy to identify and are poorly understood. This review summarizes the current knowledge on NBIA disorders, with a particular focus on the data describing the role of iron in the pathogenic mechanisms.

Antiapoptotic effects of cannabidiol in an experimental model of cognitive decline induced by brain iron overload

Iron accumulation in the brain has been recognized as a common feature of both normal aging and neurodegenerative diseases. Cognitive dysfunction has been associated to iron excess in brain regions in humans. We have previously described that iron overload leads to severe memory deficits, including spatial, recognition, and emotional memory impairments in adult rats. In the present study we investigated the effects of neonatal iron overload on proteins involved in apoptotic pathways, such as Caspase 8, Caspase 9, Caspase 3, Cytochrome c, APAF1, and PARP in the hippocampus of adult rats, in an attempt to establish a causative role of iron excess on cell death in the nervous system, leading to memory dysfunction. Cannabidiol (CBD), the main non-psychotropic component of Cannabis sativa, was examined as a potential drug to reverse iron-induced effects on the parameters analyzed. Male rats received vehicle or iron carbonyl (30 mg/kg) from the 12th to the 14th postnatal days and were treated with vehicle or CBD (10 mg/kg) for 14 days in adulthood. Iron increased Caspase 9, Cytochrome c, APAF1, Caspase 3 and cleaved PARP, without affecting cleaved Caspase 8 levels. CBD reversed iron-induced effects, recovering apoptotic proteins Caspase 9, APAF1, Caspase 3 and cleaved PARP to the levels found in controls. These results suggest that iron can trigger cell death pathways by inducing intrinsic apoptotic proteins. The reversal of iron-induced effects by CBD indicates that it has neuroprotective potential through its anti-apoptotic action.

Minocycline Effects on Intracerebral Hemorrhage-Induced Iron Overload in Aged Rats

Brain iron overload is a key factor causing brain injury after intracerebral hemorrhage (ICH). This study quantified brain iron levels after ICH with magnetic resonance imaging R2* mapping. The effect of minocycline on iron overload and ICH-induced brain injury in aged rats was also determined. Aged (18 months old) male Fischer 344 rats had an intracerebral injection of autologous blood or saline, and brain iron levels were measured by magnetic resonance imaging R2* mapping. Some ICH rats were treated with minocycline or vehicle. The rats were euthanized at days 7 and 28 after ICH, and brains were used for immunohistochemistry and Western blot analyses. Magnetic resonance imaging (T2-weighted, T2* gradient-echo, and R2* mapping) sequences were performed at different time points. ICH-induced brain iron overload in the perihematomal area could be quantified by R2* mapping. Minocycline treatment reduced brain iron accumulation, T2* lesion volume, iron-handling protein upregulation, neuronal cell death, and neurological deficits (P<0.05). Magnetic resonance imaging R2* mapping is a reliable and noninvasive method, which can quantitatively measure brain iron levels after ICH. Minocycline reduced ICH-related perihematomal iron accumulation and brain injury in aged rats.