Perinatal Iron Deficiency-Induced Hypothyroxinemia Impairs Early Brain Development Regardless of Normal Iron Levels in the Neonatal Brain

Neurovascular unit impairment in iron deficiency anemia

Iron is one of the crucial elements for CNS development and function and its deficiency (ID) is the most common worldwide nutrient deficit in the world. Iron deficiency anemia (IDA) in pregnant women and infants is a worldwide health problem due to its high prevalence and its irreversible long-lasting effects on brain development. Even with iron supplementation, IDA during pregnancy and/or breastfeeding can result in irreversible cognitive, motor, and behavioral impairments. The neurovascular unit (NVU) plays an important role in iron transport within the CNS as well as in the blood brain-barrier (BBB) formation and maturation, vasculogenesis/angiogenesis, neurovascular coupling and metabolic waste clearance. In animal models of IDA, significant changes have been observed at the capillary level, including alterations in iron transport, vasculogenesis, astrocyte endfeet, and pericytes. Despite these findings, the role of the NVU in IDA remains poorly understood. This review summarizes the potential effects of ID/IDA on brain development, myelination and neuronal function and discusses the role of NVU cells in iron metabolism, BBB, vasculogenesis/angiogenesis, neurovascular coupling and metabolic waste clearance. Furthermore, it emphasizes the need to view the NVU as a whole and as a potential target for ID/IDA. However, it remains unclear to what extent NVU alterations contribute to neuronal dysfunction, myelination abnormalities, and synaptic disturbances described in IDA.

Cellular Iron Deficiency Disrupts Thyroid Hormone Regulated Gene Expression in Developing Hippocampal Neurons

BACKGROUND

Developing neurons have high thyroid hormone and iron requirements to support their metabolically demanding growth. Early-life iron and thyroid-hormone deficiencies are prevalent and often coexist, and each independently increases risk of permanently impaired neurobehavioral function in children. Early-life dietary iron deficiency reduces thyroid-hormone concentrations and impairs thyroid hormone-responsive gene expression in the neonatal rat brain, but it is unclear whether the effect is cell-intrinsic.

OBJECTIVES

This study determined whether neuronal-specific iron deficiency alters thyroid hormone-regulated gene expression in developing neurons.

METHODS

Iron deficiency was induced in primary mouse embryonic hippocampal neuron cultures with the iron chelator deferoxamine (DFO) beginning at 3 d in vitro (DIV). At 11DIV and 18DIV, thyroid hormone-regulated gene messenger ribonucleic acid (mRNA)concentrations indexing thyroid hormone homeostasis (Hairless, mu-crystallin, Type II deiodinase, solute carrier family member 1c1, and solute carrier family member 16a2) and neurodevelopment (neurogranin, Parvalbumin, and Krüppel-like factor 9) were quantified. To assess the effect of iron repletion, DFO was removed at 14DIV from a subset of DFO-treated cultures, and gene expression and adenosine 5'-triphosphate (ATP) concentrations were quantified at 21DIV.

RESULTS

At 11DIV and 18DIV, neuronal iron deficiency decreased neurogranin, Parvalbumin, and mu-crystallin, and by 18DIV, solute carrier family member 16a2, solute carrier family member 1c1, Type II deiodinase, and Hairless were increased, suggesting cellular sensing of a functionally abnormal thyroid hormone state. Dimensionality reduction with Principal component analysis reveals that thyroid hormone homeostatic genes strongly correlate with and predict iron status. Iron repletion from 14-21DIV did not restore ATP concentration, and Principal component analysis suggests that, after iron repletion, cultures maintain a gene expression signature indicative of previous iron deficiency.

CONCLUSIONS

These novel findings suggest there is an intracellular mechanism coordinating cellular iron/thyroid hormone activities. We speculate this is a part of the homeostatic response to acutely match neuronal energy production and growth signaling. However, the adaptation to iron deficiency may cause permanent deficits in thyroid hormone-dependent neurodevelopmental processes even after recovery from iron deficiency.

Examining the Role of a Functional Deficiency of Iron in Lysosomal Storage Disorders with Translational Relevance to Alzheimer's Disease

The recently presented Azalea Hypothesis for Alzheimer's disease asserts that iron becomes sequestered, leading to a functional iron deficiency that contributes to neurodegeneration. Iron sequestration can occur by iron being bound to protein aggregates, such as amyloid β and tau, iron-rich structures not undergoing recycling (e.g., due to disrupted ferritinophagy and impaired mitophagy), and diminished delivery of iron from the lysosome to the cytosol. Reduced iron availability for biochemical reactions causes cells to respond to acquire additional iron, resulting in an elevation in the total iron level within affected brain regions. As the amount of unavailable iron increases, the level of available iron decreases until eventually it is unable to meet cellular demands, which leads to a functional iron deficiency. Normally, the lysosome plays an integral role in cellular iron homeostasis by facilitating both the delivery of iron to the cytosol (e.g., after endocytosis of the iron-transferrin-transferrin receptor complex) and the cellular recycling of iron. During a lysosomal storage disorder, an enzyme deficiency causes undigested substrates to accumulate, causing a sequelae of pathogenic events that may include cellular iron dyshomeostasis. Thus, a functional deficiency of iron may be a pathogenic mechanism occurring within several lysosomal storage diseases and Alzheimer's disease.

Cellular Iron Deficiency Disrupts Thyroid Hormone Regulated Gene Expression in Developing Hippocampal Neurons

Background

Developing neurons have high thyroid hormone and iron requirements to support their metabolism and growth. Early-life iron and thyroid hormone deficiencies are prevalent, often coexist, and increase the risk of permanently impaired neurobehavioral function in children. Early-life dietary iron deficiency reduces thyroid hormone levels and impairs thyroid hormone-responsive gene expression in the neonatal rat brain.

Objective

This study determined whether neuronal-specific iron deficiency alters thyroid hormone-regulated gene expression in developing neurons.

Methods

Iron deficiency was induced in primary mouse embryonic hippocampal neuron cultures with the iron chelator deferoxamine (DFO) beginning at 3 days in vitro (DIV). At 11DIV and 18DIV, mRNA levels for thyroid hormone-regulated genes indexing thyroid hormone homeostasis (Hr, Crym, Dio2, Slco1c1, Slc16a2) and neurodevelopment (Nrgn, Pvalb, Klf9) were quantified. To assess the effect of iron repletion, DFO was removed at 14DIV from a subset of DFO-treated cultures and gene expression and ATP levels were quantified at 21DIV.

Results

At 11DIV and 18DIV, neuronal iron deficiency decreased Nrgn, Pvalb, and Crym, and by 18DIV, Slc16a2, Slco1c1, Dio2, and Hr were increased; collectively suggesting cellular sensing of a functionally abnormal thyroid hormone state. Dimensionality reduction with Principal Component Analysis (PCA) reveals that thyroid hormone homeostatic genes strongly correlate with and predict iron status (Tfr1 mRNA). Iron repletion from 14-21DIV restored neurodevelopmental genes, but not all thyroid hormone homeostatic genes, and ATP concentrations remained significantly altered. PCA clustering suggests that cultures replete with iron maintain a gene expression signature indicative of previous iron deficiency.

Conclusions

These novel findings suggest there is an intracellular mechanism coordinating cellular iron/thyroid hormone activities. We speculate this is a part of homeostatic response to match neuronal energy production and growth signaling for these important metabolic regulators. However, iron deficiency may cause permanent deficits in thyroid hormone-dependent neurodevelopmental processes even after recovery from iron deficiency.

Iodine Deficiency, Maternal Hypothyroxinemia and Endocrine Disrupters Affecting Fetal Brain Development: A Scoping Review

This scoping review critically discusses the publications of the last 30 years on the impact of mild to moderate iodine deficiency and the additional impact of endocrine disrupters during pregnancy on embryonal/fetal brain development. An asymptomatic mild to moderate iodine deficiency and/or isolated maternal hypothyroxinemia might affect the development of the embryonal/fetal brain. There is sufficient evidence underlining the importance of an adequate iodine supply for all women of childbearing age in order to prevent negative mental and social consequences for their children. An additional threat to the thyroid hormone system is the ubiquitous exposure to endocrine disrupters, which might exacerbate the effects of iodine deficiency in pregnant women on the neurocognitive development of their offspring. Ensuring adequate iodine intake is therefore essential not only for healthy fetal and neonatal development in general, but it might also extenuate the effects of endocrine disruptors. Individual iodine supplementation of women of childbearing age living in areas with mild to moderate iodine deficiency is mandatory as long as worldwide universal salt iodization does not guarantee an adequate iodine supply. There is an urgent need for detailed strategies to identify and reduce exposure to endocrine disrupters according to the "precautional principle".

“Ferrocrinology”—Iron Is an Important Factor Involved in Gluco- and Lipocrinology

“Ferrocrinology” is the term used to describe the study of iron effects on the functioning of adipose tissue, which together with muscle tissue makes the largest endocrine organ in the human body. By impairing exercise capacity, reducing AMP-activated kinase activity, and enhancing insulin resistance, iron deficiency can lead to the development of obesity and type 2 diabetes mellitus. Due to impaired browning of white adipose tissue and reduced mitochondrial iron content in adipocytes, iron deficiency (ID) can cause dysfunction of brown adipose tissue. By reducing ketogenesis, aconitase activity, and total mitochondrial capacity, ID impairs muscle performance. Another important aspect is the effect of ID on the impairment of thermogenesis due to reduced binding of thyroid hormones to their nuclear receptors, with subsequently impaired utilization of norepinephrine in tissues, and impaired synthesis and distribution of cortisol, which all make the body’s reactivity to stress in ID more pronounced. Iron deficiency can lead to the development of the most common endocrinopathy, autoimmune thyroid disease. In this paper, we have discussed the role of iron in the cross-talk between glucocrinology, lipocrinology and myocrinology, with thyroid hormones acting as an active bystander.

Iron: Not Just a Passive Bystander in AITD

Autoimmune thyroid disease (AITD) is the most prevalent autoimmune disease all over the world and the most frequent cause of hypothyroidism in areas of iodine sufficiency. The pathogenesis of AITD is multifactorial and depends on complex interactions between genetic and environmental factors, with epigenetics being the crucial link. Iron deficiency (ID) can reduce the activities of thyroid peroxidase and 5′-deiodinase, inhibit binding of triiodothyronine to its nuclear receptor, and cause slower utilization of T3 from the serum pool. Moreover, ID can disturb the functioning of the immune system, increasing the risk of autoimmune disorders. ID can be responsible for residual symptoms that may persist in patients with AITD, even if their thyrometabolic status has been controlled. The human lifestyle in the 21st century is inevitably associated with exposure to chemical compounds, pathogens, and stress, which implies an increased risk of autoimmune disorders and thyroid dysfunction. To summarize, in our paper we discuss how iron deficiency can impair the functions of the immune system, cause epigenetic changes in human DNA, and potentiate tissue damage by chemicals acting as thyroid disruptors.

Can Iron Play a Crucial Role in Maintaining Cardiovascular Health in the 21st Century?

In the 21st century the heart is facing more and more challenges so it should be brave and iron to meet these challenges. We are living in the era of the COVID-19 pandemic, population aging, prevalent obesity, diabetes and autoimmune diseases, environmental pollution, mass migrations and new potential pandemic threats. In our article we showed sophisticated and complex regulations of iron metabolism. We discussed the impact of iron metabolism on heart diseases, treatment of heart failure, diabetes and obesity. We faced the problems of constant stress, climate change, environmental pollution, migrations and epidemics and showed that iron is really essential for heart metabolism in the 21st century.

Iron Deficiency Is a Risk Factor for Thyroid Dysfunction During Pregnancy: A Population-Based Study in Belgium

Background: Iron deficiency affects thyroid hormone synthesis by impairing the activity of the heme-dependent thyroid peroxidase. The prevalence of iron deficiency is elevated particularly in pregnant women. This study aimed to investigate the effects of iron status on thyroid function in a nationally representative sample of mildly iodine-deficient pregnant women. Methods: The study population comprised a sample of pregnant women in Belgium during the first and third trimesters of pregnancy (n = 1241). Women were selected according to a multistage proportional-to-size stratified and clustered sampling design. Urine and blood samples were collected, and a questionnaire was completed face to face with the study nurse. Concentrations of free thyroxine (fT4), total thyroxine (T4), free triiodothyronine, thyrotropin (TSH), thyroglobulin (Tg), thyroid peroxidase antibodies, Tg antibodies, hemoglobin, serum ferritin (SF), soluble transferrin receptor, urinary iodine concentrations (UICs) were measured and body iron stores (BIS) were calculated. Results: Median UICs were 117 and 132 μg/L in the first and third trimesters of pregnancy, respectively (p < 0.05). The frequency of SF <15 μg/L was 6.2% in the first trimester and 39.6% in the third trimester of pregnancy (p < 0.05). UIC was a significant predictor of serum Tg concentrations (p < 0.01) but not of thyroid hormone or TSH concentrations. The frequency of fT4<percentile 10th in the third trimester of pregnancy was 24% and 14% in pregnant women with negative BIS and positive BIS, respectively (p < 0.05). SF and BIS were significant predictors of fT4 and T4 in the first trimester of pregnancy (p < 0.05). Hemoglobin was a significant predictor of fT4 in both trimesters (p < 0.01) and for T4 in the third trimester (p = 0.015). Conclusion: Iron deficiency, but not mild iodine deficiency, is a determinant of serum fT4 and T4 in pregnant women. Correcting iron deficiency may help to maintain optimal thyroid function, in addition to preventing anemia during pregnancy.

The Effects of Early-Life Iron Deficiency on Brain Energy Metabolism

Iron deficiency (ID) is one of the most prevalent nutritional deficiencies in the world. Iron deficiency in the late fetal and newborn period causes abnormal cognitive performance and emotional regulation, which can persist into adulthood despite iron repletion. Potential mechanisms contributing to these impairments include deficits in brain energy metabolism, neurotransmission, and myelination. Here, we comprehensively review the existing data that demonstrate diminished brain energetic capacity as a mechanistic driver of impaired neurobehavioral development due to early-life (fetal-neonatal) ID. We further discuss a novel hypothesis that permanent metabolic reprogramming, which occurs during the period of ID, leads to chronically impaired neuronal energetics and mitochondrial capacity in adulthood, thus limiting adult neuroplasticity and neurobehavioral function. We conclude that early-life ID impairs energy metabolism in a brain region- and age-dependent manner, with particularly strong evidence for hippocampal neurons. Additional studies, focusing on other brain regions and cell types, are needed.

Impairment of the Developing Human Brain in Iron Deficiency: Correlations to Findings in Experimental Animals and Prospects for Early Intervention Therapy

Due to the necessity of iron for a variety of cellular functions, the developing mammalian organism is vulnerable to iron deficiency, hence causing structural abnormalities and physiological malfunctioning in organs, which are particularly dependent on adequate iron stores, such as the brain. In early embryonic life, iron is already needed for proper development of the brain with the proliferation, migration, and differentiation of neuro-progenitor cells. This is underpinned by the widespread expression of transferrin receptors in the developing brain, which, in later life, is restricted to cells of the blood–brain and blood–cerebrospinal fluid barriers and neuronal cells, hence ensuring a sustained iron supply to the brain, even in the fully developed brain. In embryonic human life, iron deficiency is thought to result in a lower brain weight, with the impaired formation of myelin. Studies of fully developed infants that have experienced iron deficiency during development reveal the chronic and irreversible impairment of cognitive, memory, and motor skills, indicating widespread effects on the human brain. This review highlights the major findings of recent decades on the effects of gestational and lactational iron deficiency on the developing human brain. The findings are correlated to findings of experimental animals ranging from rodents to domestic pigs and non-human primates. The results point towards significant effects of iron deficiency on the developing brain. Evidence would be stronger with more studies addressing the human brain in real-time and the development of blood biomarkers of cerebral disturbance in iron deficiency. Cerebral iron deficiency is expected to be curable with iron substitution therapy, as the brain, privileged by the cerebral vascular transferrin receptor expression, is expected to facilitate iron extraction from the circulation and enable transport further into the brain.

Iron Deficiency May Predict Greater Risk for Hypothyroxinemia: A Retrospective Cohort Study of Pregnant Women in China

BACKGROUND

Pregnant women are highly vulnerable to iron deficiency (ID) due to the increased iron needs during pregnancy. ID decreases circulating thyroid hormone concentrations likely through impairment of iron-dependent thyroid peroxidase. The present study aimed to explore the association between ID and hypothyroxinemia in a retrospective cohort of pregnant women in China.

METHODS

To investigate the relationship between ID and hypothyroxinemia, 723 pregnant women were retrospectively analyzed, including 675 and 309 women in the second and third trimesters, respectively. Trimester-specific hypothyroxinemia was defined as free thyroxine (fT4) levels below the 2.5th percentile of the reference range with normal serum thyrotropin (TSH) or TSH higher than the 97.5th percentile of the reference range in each trimester of pregnancy. Serum TSH, fT4, thyroid peroxidase antibodies, thyroglobulin antibodies, serum ferritin, soluble transferrin receptor, and urinary iodine concentrations were measured. Serum ferritin, soluble transferrin receptor, and total body iron were used to indicate the nutritional iron status.

RESULTS

Cross-sectional multiple linear regression analysis showed that iron status was positively associated with serum fT4 levels in the first and second trimesters of pregnancy, but not in the third trimester. Logistic regression analysis showed that ID was an independent risk factor for hypothyroxinemia (odds ratio = 14.86 [confidence interval 2.31-95.81], p = 0.005 in the first trimester and odds ratio = 3.36 [confidence interval 1.01-11.21], p = 0.048 in the second trimester). The prospective analysis showed that pregnant women with ID during the first trimester of pregnancy had lower serum fT4 levels and a higher rate of hypothyroxinemia in the second or third trimester than those without ID.

CONCLUSIONS

ID appears to be a risk factor to predict hypothyroxinemia in the first and second trimesters of pregnancy, but not in the third trimester. Pregnant women with ID in the first and second trimesters should be regarded as a high-risk group for maternal hypothyroxinemia.

Gestational Hypothyroxinemia Affects Its Offspring With a Reduced Suppressive Capacity Impairing the Outcome of the Experimental Autoimmune Encephalomyelitis

Hypothyroxinemia (Hpx) is a thyroid hormone deficiency (THD) condition highly frequent during pregnancy, which although asymptomatic for the mother, it can impair the cognitive function of the offspring. Previous studies have shown that maternal hypothyroidism increases the severity of experimental autoimmune encephalomyelitis (EAE), an autoimmune disease model for multiple sclerosis (MS). Here, we analyzed the immune response after EAE induction in the adult offspring gestated in Hpx. Mice gestated in Hpx showed an early appearance of EAE symptoms and the increase of all parameters of the disease such as: the pathological score, spinal cord demyelination, and immune cell infiltration in comparison to the adult offspring gestated in euthyroidism. Isolated CD4⁺CD25⁺ T cells from spleen of the offspring gestated in Hpx that suffer EAE showed reduced capacity to suppress proliferation of effector T cells (T_Eff) after being stimulated with anti-CD3 and anti-CD28 antibodies. Moreover, adoptive transfer experiments of CD4⁺CD25⁺ T cells from the offspring gestated in Hpx suffering EAE to mice that were induced with EAE showed that the receptor mice suffer more intense EAE pathological score. Even though, no significant differences were detected in the frequency of T_reg cells and IL-10 content in the blood, spleen, and brain between mice gestated in Hpx or euthyroidism, T cells CD4⁺CD25⁺ from spleen have reduced capacity to differentiate in vitro to T_reg and to produce IL-10. Thus, our data support the notion that maternal Hpx can imprint the immune response of the offspring suffering EAE probably due to a reduced capacity to trigger suppression. Such “imprints” on the immune system could contribute to explaining as to why adult offspring gestated in Hpx suffer earlier and more intense EAE.

Iron deficiency is associated with Hypothyroxinemia and Hypotriiodothyroninemia in the Spanish general adult population: Di@bet.es study

Previous studies have suggested that iron deficiency (ID) may impair thyroid hormone metabolism, however replication in wide samples of the general adult population has not been performed. We studied 3846 individuals free of thyroid disease, participants in a national, cross sectional, population based study representative of the Spanish adult population. Thyroid stimulating hormone (TSH), free thyroxin (FT4) and free triiodothyronine (FT3) were analyzed by electrochemiluminescence (E170, Roche Diagnostics). Serum ferritin was analyzed by immunochemiluminescence (Architect I2000, Abbott Laboratories). As ferritin levels decreased (>100, 30–100, 15–30, <15 µg/L) the adjusted mean concentrations of FT4 (p < 0.001) and FT3 (p < 0.001) descended, whereas TSH levels remained unchanged (p = 0.451). In multivariate logistic regression models adjusted for age, sex, UI, BMI and smoking status, subjects with ferritin levels <30 µg/L were more likely to present hypothyroxinemia (FT4 < 12.0 pmol/L p5): OR 1.5 [1.1–2.2] p = 0.024, and hypotriiodothyroninemia (FT3 < 3.9 pmol/L p5): OR 1.8 [1.3–2.6] p = 0.001 than the reference category with ferritin ≥30 µg/L. There was no significant heterogeneity of the results between men, pre-menopausal and post-menopausal women or according to the iodine nutrition status. Our results confirm an association between ID and hypothyroxinemia and hypotriiodothyroninemia in the general adult population without changes in TSH.

Serum Trace Elements Profile in Graves' Disease Patients with or without Orbitopathy in Northeast China

Objective

The purpose of the present study was to investigate serum trace elements in Graves' disease (GD) patients with or without orbitopathy in Northeast China.

Methods

Patients with newly diagnosed Graves' disease (HyGD) (n = 66), GD patients with euthyroid status or subclinical thyroidism after treatment (EUGD) (n = 55), GO patients with euthyroid status or subclinical thyroidism after treatment (GO) (n = 57), and normal controls (NC) (n = 66) were enrolled in this study. Serum trace elements were measured with ICP-MS.

Results

Serum selenium (Se) levels in EUGD group (median: 7.53 µg/dL), HyGD group (median: 6.76 µg/dL), and GO group (median: 7.40 µg/dL) were significantly lower than those in NC group (median: 9.20 µg/dL, all P < 0.01). Serum copper (Cu) levels in GO group (median: 95.93 µg/dL) were significantly lower than those in the NC group (median: 113.59 µg/dL, P = 0.015). After being adjusted for multivariables, thyroid-specific antibodies grade was associated with low Se levels. Hyperthyroidism and thyroid-specific antibodies grade were associated with high Cu levels. In addition, orbitopathy was associated with low Cu levels.

Conclusions

Thyroid autoimmunity was associated with low Se levels. Hyperthyroidism and thyroid autoimmunity may be associated with relatively high serum Cu levels. Alternatively, ophthalmopathy may be related to low serum Cu levels.

Elevated Thyroid Peroxidase Antibody Increases Risk of Post-partum Depression by Decreasing Prefrontal Cortex BDNF and 5-HT Levels in Mice

Post-partum depression (PPD) is a common mental disease in the perinatal period that profoundly affects mothers and their offspring. Some clinical studies have found that PPD is related to thyroid peroxidase antibodies (TPOAbs); however, the mechanism underlying this relationship is unclear. Female C57BL/6 mice immunized with adenovirus encoding the cDNA of the full-length mTPO (mTPO-Ad) were used to establish the isolated TPOAb-positive mouse model in the present study. Maternal depressive-like behaviors were assessed using the forced swimming test (FST), sucrose preference test (SPT), and tail suspension test (TST) post-partum. The serum TPOAb titer was measured by enzyme-linked immunosorbent assay (ELISA) before pregnancy and post-partum. Furthermore, in the prefrontal cortex, the mRNA and protein expression levels of brain-derived neurotrophic factor (BDNF) were measured, serotonin (5-HT) levels were measured by ultra-high-performance liquid chromatography–tandem mass-spectrometry (UHPLC–MS/MS), and total thyroxine (TT4) levels were determined by ELISA. Compared with the controls, the mice immunized with mTPO-Ad displayed depressive behaviors, with a significantly lower sucrose preference (SP) at the 12-h time point and a longer immobility time in the FST and TST, which were accompanied by a lower expression of BDNF and 5-HT but no change in the TT4 concentration in the prefrontal cortex. Together, these findings suggest that elevated TPOAb may increase the risk of subsequent PPD and decrease the concentration of BDNF and 5-HT in the prefrontal cortex.

The role of cord blood BDNF in infant cognitive impairment induced by low-level prenatal manganese exposure: LW birth cohort, China

This study aimed to examine the potential association between low-level prenatal manganese (Mn) exposure and 1-year-old children's neurodevelopment quotient (DQ) by using the Gesell Developmental Inventory (GDI) (motor, adaptive, language, and social domains) and explored the role of brain-derived neurotrophic factor (BDNF) in Mn-induced cognitive impairments. A total of 377 mothers were recruited from a prospective birth cohort in rural northern China. Cord serum concentrations of Mn and BDNF were measured and children's DQ was evaluated. The median serum Mn concentration was 3.4 μg/L. After adjusting for confounding factors, Mn level was significantly associated with gross motor scores (β = -6.0, 95% CI: -11.8 to -0.2, p < 0.05) and personal-social scores (β = -4.2, 95% CI: -8.4 to 0.1, p < 0.05). BDNF level was positively correlated with personal-social score (β = 0.7, 95% CI: 0-1.4, p < 0.05). A significant correlation was found between Mn and BDNF (r = -0.13, 95% CI: -0.23 to -0.03, p < 0.01). Furthermore, the interaction between cord serum Mn and BDNF was significant (p < 0.001). In conclusion, elevated low-level prenatal Mn exposure impaired infant's neurodevelopment, and BDNF plays an important role in cognitive impairment, especially in the personal-social ability.