Bone remodelling is reduced by recovery from iron-deficiency anaemia in premenopausal women

Fibroblast growth factor 23 is pumping iron: C-terminal-fibroblast growth factor 23 cleaved peptide and its function in iron metabolism

PURPOSE OF REVIEW

Iron deficiency regulates the production of the bone-derived phosphaturic hormone fibroblast growth factor 23 (FGF23) but also its cleavage, to generate both intact (iFGF23) and C-terminal (Cter)-FGF23 peptides. Novel studies demonstrate that independently of the phosphaturic effects of iFGF23, Cter-FGF23 peptides play an important role in the regulation of systemic iron homeostasis. This review describes the complex interplay between iron metabolism and FGF23 biology.

RECENT FINDINGS

C-terminal (Cter) FGF23 peptides antagonize inflammation-induced hypoferremia to maintain a pool of bioavailable iron in the circulation. A key mechanism proposed is the down-regulation of the iron-regulating hormone hepcidin by Cter-FGF23.

SUMMARY

In this manuscript, we discuss how FGF23 is produced and cleaved in response to iron deficiency, and the principal functions of cleaved C-terminal FGF23 peptides. We also review possible implications anemia of chronic kidney disease (CKD).

Iron status is associated with tibial structure and vitamin D metabolites in healthy young men

The influence of iron on collagen synthesis and vitamin D metabolism has implications for bone health. This cross-sectional observational study investigated associations between markers of iron status and tibial structure, vitamin D metabolites, and circulating biochemical markers of bone metabolism in young healthy men. A total of 343 male British Army recruits participated (age 22 ± 3 y, height 1.77 ± 0.06 m, body mass 75.5 ± 10.1 kg). Circulating biochemical markers of iron status, vitamin D metabolites, and bone metabolism, and tibial structure and density by high-resolution peripheral quantitative computed tomography scans (HRpQCT) were measured in participants during week 1 of basic military training. Associations between markers of iron status and HRpQCT outcomes, bone metabolism, and vitamin D metabolites were tested, controlling for age, height, lean body mass, and childhood exercise volume. Higher ferritin was associated with higher total, trabecular, and cortical volumetric bone mineral density, trabecular volume, cortical area and thickness, stiffness, and failure load (all p ≤ 0.037). Higher soluble transferrin receptor (sTfR) was associated with lower trabecular number, and higher trabecular thickness and separation, cortical thickness, and cortical pore diameter (all p ≤ 0.033). Higher haemoglobin was associated with higher cortical thickness (p = 0.043). Higher ferritin was associated with lower βCTX, PINP, total 25(OH)D, and total 24,25(OH)2D, and higher 1,25(OH)2D:24,25(OH)2D ratio (all p ≤ 0.029). Higher sTfR was associated with higher PINP, total 25(OH)D, and total 24,25(OH)2D (all p ≤ 0.025). The greater density, size, and strength of the tibia, and lower circulating concentrations of markers of bone resorption and formation with better iron stores (higher ferritin) are likely as a result of the direct role of iron in collagen synthesis.

Female rats consuming an iron and omega-3 fatty acid deficient diet preconception require combined iron and omega-3 fatty acid supplementation for the prevention of bone impairments in offspring

We previously showed in rats that pre- and postnatal deficiencies in iron and omega-3 (n-3) fatty acids can impair bone development, with additive and potentially irreversible effects when combined. This study aimed to investigate, in female rats consuming a combined iron and n-3 fatty acid deficient (ID + n-3 FAD) diet preconception, whether supplementation with iron and docosahexaenoic/eicosapentaenoic acid (DHA/EPA), alone and in combination, can prevent bone impairments in offspring. Using a 2 × 2 factorial design, female Wistar rats consuming an ID + n-3 FAD diet preconception were randomised to receive an: 1) iron supplemented (Fe + n-3 FAD), 2) DHA/EPA supplemented (ID + DHA/EPA), 3) Fe + DHA/EPA, or 4) ID + n-3 FAD diet from gestational day 10 throughout pregnancy and lactation. Post-weaning, offspring (n = 24/group; male:female = 1:1) remained on the respective experimental diets for three weeks until postnatal day 42-45. Offspring born to female rats consuming a control diet preconception and an Fe+DHA/EPA diet throughout pregnancy and lactation served as non-deficient reference group (Control+Fe+DHA/EPA). Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry and bone strength using three-point bending tests. Only offspring in the Fe+DHA/EPA group had significantly higher spine and femur BMD, and higher femur stiffness than offspring in the ID + n-3 FAD group, and had similar spine BMD and femur stiffness as the Control + Fe + DHA/EPA group. Offspring in the Fe + DHA/EPA group further had significantly higher femur strength (ultimate load) than the other experimental groups, and a similar femur strength as the Control + Fe + DHA/EPA group. This study shows that only combined iron and DHA/EPA supplementation can prevent bone impairments in offspring of female rats consuming an iron and n-3 FA deficient diet preconception.

Sex differences in iron status during military training: a prospective cohort study of longitudinal changes and associations with endurance performance and musculoskeletal outcomes

This study investigated sex differences in Fe status, and associations between Fe status and endurance and musculoskeletal outcomes, in military training. In total, 2277 British Army trainees (581 women) participated. Fe markers and endurance performance (2·4 km run) were measured at the start (week 1) and end (week 13) of training. Whole-body areal body mineral density (aBMD) and markers of bone metabolism were measured at week 1. Injuries during training were recorded. Training decreased Hb in men and women (mean change (-0·1 (95 % CI -0·2, -0·0) and -0·7 (95 % CI -0·9, -0·6) g/dl, both P < 0·001) but more so in women (P < 0·001). Ferritin decreased in men and women (-27 (95 % CI -28, -23) and -5 (95 % CI -8, -1) µg/l, both P ≤ 0·001) but more so in men (P < 0·001). Soluble transferrin receptor increased in men and women (2·9 (95 % CI 2·3, 3·6) and 3·8 (95 % CI 2·7, 4·9) nmol/l, both P < 0·001), with no difference between sexes (P = 0·872). Erythrocyte distribution width increased in men (0·3 (95 % CI 0·2, 0·4)%, P < 0·001) but not in women (0·1 (95 % CI -0·1, 0·2)%, P = 0·956). Mean corpuscular volume decreased in men (-1·5 (95 % CI -1·8, -1·1) fL, P < 0·001) but not in women (0·4 (95 % CI -0·4, 1·3) fL, P = 0·087). Lower ferritin was associated with slower 2·4 km run time (P = 0·018), sustaining a lower limb overuse injury (P = 0·048), lower aBMD (P = 0·021) and higher beta C-telopeptide cross-links of type 1 collagen and procollagen type 1 N-terminal propeptide (both P < 0·001) controlling for sex. Improving Fe stores before training may protect Hb in women and improve endurance and protect against injury.

Enhancing vitamin D3 - iron blends via twin-screw dry granulation: Microstructural properties and cellular uptake analysis of vitamin D3

The aim of this study was to develop vitamin D3 (VD3) and iron (Fe) blended granules using Neusilin® US2 as an excipient. A central composite design of experiments was used for the continuous manufacturing process, considering VD3 and iron as independent variables and the bulk density, flow index, oil holding capacity, and color difference as response variables. The addition of VD3 had a significant effect on the powder flow properties. The X-ray diffraction and Scanning electron microscopy-energy dispersive X-ray analysis validated the presence of VD3 and Fe in the granules, whereas the variations in porosity and roughness were demonstrated by tomography and atomic force microscopy, respectively. The in vitro cellular uptake profile confirmed the absorption of VD3 in the breast cancer cell line MCF-7 with apparent apoptosis. These results could help in scaling up the process from laboratory to pilot scale in twin-screw granulation and boost the intervention of VitD3/iron deficiencies.

Iron Deficiency and Iron Deficiency Anemia: Potential Risk Factors in Bone Loss

Iron is one of the essential mineral elements for the human body and this nutrient deficiency is a worldwide public health problem. Iron is essential in oxygen transport, participates in many enzyme systems in the body, and is an important trace element in maintaining basic cellular life activities. Iron also plays an important role in collagen synthesis and vitamin D metabolism. Therefore, decrease in intracellular iron can lead to disturbance in the activity and function of osteoblasts and osteoclasts, resulting in imbalance in bone homeostasis and ultimately bone loss. Indeed, iron deficiency, with or without anemia, leads to osteopenia or osteoporosis, which has been revealed by numerous clinical observations and animal studies. This review presents current knowledge on iron metabolism under iron deficiency states and the diagnosis and prevention of iron deficiency and iron deficiency anemia (IDA). With emphasis, studies related to iron deficiency and bone loss are discussed, and the potential mechanisms of iron deficiency leading to bone loss are analyzed. Finally, several measures to promote complete recovery and prevention of iron deficiency are listed to improve quality of life, including bone health.

Fighting age-related orthopedic diseases: focusing on ferroptosis

Ferroptosis, a unique type of cell death, is characterized by iron-dependent accumulation and lipid peroxidation. It is closely related to multiple biological processes, including iron metabolism, polyunsaturated fatty acid metabolism, and the biosynthesis of compounds with antioxidant activities, including glutathione. In the past 10 years, increasing evidence has indicated a potentially strong relationship between ferroptosis and the onset and progression of age-related orthopedic diseases, such as osteoporosis and osteoarthritis. Therefore, in-depth knowledge of the regulatory mechanisms of ferroptosis in age-related orthopedic diseases may help improve disease treatment and prevention. This review provides an overview of recent research on ferroptosis and its influences on bone and cartilage homeostasis. It begins with a brief overview of systemic iron metabolism and ferroptosis, particularly the potential mechanisms of ferroptosis. It presents a discussion on the role of ferroptosis in age-related orthopedic diseases, including promotion of bone loss and cartilage degradation and the inhibition of osteogenesis. Finally, it focuses on the future of targeting ferroptosis to treat age-related orthopedic diseases with the intention of inspiring further clinical research and the development of therapeutic strategies.

Emerging Potential Therapeutic Targets of Ferroptosis in Skeletal Diseases

Ferroptosis is a new programmed cell death characterized by the accumulation of lipid peroxidation mediated by iron and inflammation. Since the transcentury realization of ferroptosis as an iron-dependent modality of nonapoptotic cell death in 2012, there has been growing interest in the function of ferroptosis and its relationship to clinical diseases. Recent studies have shown that ferroptosis is associated with multiple diseases, including degenerative diseases, ischemia reperfusion injury, cardiovascular disease, and cancer. Cell death induced by ferroptosis has also been related to several skeletal diseases, such as inflammatory arthritis, osteoporosis, and osteoarthritis. Research on ferroptosis can clarify the pathogenesis of skeletal diseases and provide a novel therapeutic target for its treatment. In this review, we summarize current information about the molecular mechanism of ferroptosis and describe its emerging role and therapeutic potential in skeletal diseases.

Ultrasound-Assisted Extraction of Micro- and Macroelements in Fruit Peel Powder Mineral Supplement for Osteoporosis Patients and Their Determination by Flame Atomic Absorption Spectrometry

Osteoporosis is a worldwide disease depicted by the reduced bone mass, an adequate supply of minerals is needed to support bone remodeling, and their deficiency causes bone-related diseases, osteoporosis in particular, and has osteoprotective effects. The aim of this recent research was to quantify the micro- (Mn, Fe, Cu, and Zn) and macroelements (Mg, K, and Ca) in the peel powder of some common fruits (pomegranate, orange, lemon, mango, and grapefruit) by flame atomic absorption spectrometer (FAAS). The extraction of micro- and macroelements in peel powder was done by using dilute acids in an ultrasonic bath. Apple leaves were used as standard reference material (SRM, NIST 1515) to optimize the ultrasound-assisted extraction (UAE) method at varied operating parameters. Maximum response was obtained for extracting of minerals in 500 mg SRM at 60°C temperature, setting a vortexing time of 5 min while using 5.0 mL extracting agent HNO3 (0.5 M)-H2O2 (10%) at 90% sonication amplitude of ultrasound bath for 6 min. While analyzing the SRM, the percentage recovery was obtained in a range between 96.8 and 102.7% to assure the accuracy whereas repeatability (n = 10) study in terms of % RSD yielding ≤2.29 supports well the precision of the proposed method, and limits of quantitation (μg/g) were 0.034, 0.061, 0.065, 0.057, 0.017, 0.175, and 0.053 for Mn, Fe, Cu, Zn, Mg, K, and Ca, respectively. The proposed UAE method was reliable, efficient, and advantageous over the conventionally employed acid digestion method with regard to less consumption of reagents and short analysis time for the determination of micro- and macroelements in fruit peel powder.

Rapid and Effective Vitamin D Supplementation May Present Better Clinical Outcomes in COVID-19 (SARS-CoV-2) Patients by Altering Serum INOS1, IL1B, IFNg, Cathelicidin-LL37, and ICAM1

Background: We aimed to establish an acute treatment protocol to increase serum vitamin D, evaluate the effectiveness of vitamin D3 supplementation, and reveal the potential mechanisms in COVID-19. Methods: We retrospectively analyzed the data of 867 COVID-19 cases. Then, a prospective study was conducted, including 23 healthy individuals and 210 cases. A total of 163 cases had vitamin D supplementation, and 95 were followed for 14 days. Clinical outcomes, routine blood biomarkers, serum levels of vitamin D metabolism, and action mechanism-related parameters were evaluated. Results: Our treatment protocol increased the serum 25OHD levels significantly to above 30 ng/mL within two weeks. COVID-19 cases (no comorbidities, no vitamin D treatment, 25OHD <30 ng/mL) had 1.9-fold increased risk of having hospitalization longer than 8 days compared with the cases with comorbidities and vitamin D treatment. Having vitamin D treatment decreased the mortality rate by 2.14 times. The correlation analysis of specific serum biomarkers with 25OHD indicated that the vitamin D action in COVID-19 might involve regulation of INOS1, IL1B, IFNg, cathelicidin-LL37, and ICAM1. Conclusions: Vitamin D treatment shortened hospital stay and decreased mortality in COVID-19 cases, even in the existence of comorbidities. Vitamin D supplementation is effective on various target parameters; therefore, it is essential for COVID-19 treatment.

The Ideal Time for Iron Administration in Anemia Secondary to Blood Loss-An Experimental Animal Model

BACKGROUND

Anemia and iron deficiency are two of the main public health problems worldwide, associated with negative outcomes in surgical patients. This experimental study aimed to create a model of acute iron deficiency with anemia through blood loss and extensive surgery. Afterwards, intravenous iron was administered to correct the iron deficiency and to improve the hematological parameters in distinct moments regarding the surgical time. To assess the optimum time for therapeutic intervention, experimental subjects were compared, performing clinical, paraclinical, and histological examinations, as well.

METHODS

Male rats (n = 35), aged 11-13 months, were randomly designated into six groups. Anemia and iron deficiency were obtained through a 15% blood volume loss, followed by major surgical intervention (femur fracture and osteosynthesis using Kirschner wire). Therapeutic intervention was obtained with an intravenous ferric carboxymaltose infusion, as follows: group II: intraoperative (n = 7), group III: 48 h after surgery (n = 7), group IV: 48 h before surgery (n = 5), and group V: seven days before surgery (n = 6). Group I (n = 5) was left anemic, while group 0 (n = 5) was nonanemic without therapeutic intervention.

RESULTS AND DISCUSSION

In group I, serum iron lower than in group 0 (27.04 ± 6.92 μg/dL versus 60.5 ± 2.34 μg/dL), as well as hemoglobin (10.4 ± 0.54 g/dL versus 14.32 ± 2.01 g/dL) and ferritin values (22.52 ± 0.53 ng/mL versus 29.86 ± 3.97 ng/mL), validated the experimental model. Regarding wound healing after surgical trauma, we observed that neovascularization was more significant in group III, followed by group V, with fewer neutrophils, a well-represented and rich in lymphomonocytes inflammatory infiltrate associated with the biggest collagen fiber dimensions. The periosteal reaction and callus area presented thicker trabeculae in groups II and III compared to the anemic group.

CONCLUSIONS

This original experimental study assessed the effect of perioperative intravenous iron administration at a specific time by comparing the weight, hematological, and iron status-defining parameters, as well as histological characteristics of the included subjects. The present findings highlight that correcting the iron deficiency in emergency settings through intravenous iron administration intraoperatively or 48 h postoperatively could determine the improved bioumoral parameters, as well as a better evolution of the postoperative wound and bone healing compared to the anemic group or subjects that received therapeutic intervention 48 h before surgery.

The critical roles of iron during the journey from fetus to adolescent: Developmental aspects of iron homeostasis

Iron is indispensable for human life. However, it is also potentially toxic, since it catalyzes the formation of harmful oxidative radicals in unbound form and may facilitate pathogen growth. Therefore, iron homeostasis needs to be tightly regulated. Rapid growth and development require large amounts of iron, while (especially young) children are vulnerable to infections with iron-dependent pathogens due to an immature immune system. Moreover, unbalanced iron status early in life may have effects on the nervous system, immune system and gut microbiota that persist into adulthood. In this narrative review, we assess the critical roles of iron for growth and development and elaborate how the body adapts to physiologically high iron demands during the journey from fetus to adolescent. As a first step towards the development of clinical guidelines for the management of iron disorders in children, we summarize the unmet needs regarding the developmental aspects of iron homeostasis.

Changes in Bone Turnover, Inflammatory, Oxidative Stress, and Metabolic Markers in Women Consuming Iron plus Vitamin D Supplements: a Randomized Clinical Trial

We aimed to investigate whether combination of vitamin D and iron supplementation, comparing vitamin D alone, could modify bone turnover, inflammatory, oxidative stress, and metabolic markers. Eighty-seven women with hemoglobin (Hb) ≤ 12.7 g/dL and 25OHD ≤ 29 ng/mL vitamin D deficiency/insufficiency aged 18-45 years were randomly assigned into two groups: (1) receiving either 1000 IU/day vitamin D3 plus 27 mg/day iron (D-Fe); (2) vitamin D3 plus placebo supplements (D-P), for 12 weeks. In D-Fe group, significant decrease in red blood cells (RBC) (P = 0.001) and hematocrit (Hct) (P = 0.004) and increases in mean corpuscular hemoglobin concentration (MCHC) (P = 0.001), 25OHD (P < 0.001), osteocalcin (P < 0.001), high-density cholesterol (HDL) (P = 0.041), and fasting blood sugar (FBS) (P < 0.001) were observed. D-P group showed significant decrease in RBC (P < 0.001), Hb (P < 0.001), Hct (P < 0.001), mean corpuscular volume (MCV) (P = 0.004), mean corpuscular hemoglobin (MCH) (P < 0.001), MCHC (P = 0.005), serum ferritin (P < 0.001), and low-density cholesterol (LDL) (P = 0.016) and increases of 25OHD (P < 0.001), osteocalcin (P < 0.001), C-terminal telopeptide (CTX) (P = 0.025), triglyceride (TG) (P = 0.004), FBS (P < 0.001), and interleukin-6 (IL-6) (P = 0.001) at week 12. After the intervention, the D-P group had between-group increases in mean change in the osteocalcin (P = 0.007) and IL-6 (P = 0.033), and decreases in the RBC (P < 0.001), Hb (P < 0.001), Hct (P < 0.001), and MCV (P = 0.001), compared with the D-Fe group. There were significant between-group changes in MCH (P < 0.001), MCHC (P < 0.001), ferritin (P < 0.001), and serum iron (P = 0.018). Iron-vitamin D co-supplementation does not yield added benefits for improvement of bone turnover, inflammatory, oxidative stress, and metabolic markers, whereas, vitamin D alone may have some detrimental effects on inflammatory and metabolic markers. IRCT registration number: IRCT201409082365N9.

The associations between serum trace elements and bone mineral density in children under 3 years of age

We examined the associations of age and serum magnesium, iron, lead, copper, and zinc levels with bone mineral density (BMD) in 2412 children under 3 years of age in order to find a tool to monitor BMD in children without the use of expensive imaging techniques. One-way ANOVA and chi-square tests were used to determine the associations of age and serum trace elements with BMD. Multivariable logistic regression analysis was used to test the correlation of five serum trace elements with BMD after adjustments for potential confounding factors in children under 3 years of age. Significant associations between age and four serum trace elements and BMD were found. Compared to the group with the lowest serum levels detected, the adjusted odds ratio (OR) for the incidence of normal bone mineral density in the third magnesium concentration tertile, the third iron concentration tertile, the fifth copper concentration quintile, the third zinc concentration quintile, and the fifth zinc concentration quintile were 1.30 (95% confidence interval (CI) 1.02–1.67), 1.43 (95% CI 1.11–1.84), 1.42 (95% CI 1.04–1.94), 1.46 (95% CI 1.05–2.04), and 1.48 (95% CI 1.06–2.06), respectively. However, there was no significant correlation between serum lead level and BMD in this study. Age and serum magnesium, iron, copper, and zinc levels are positively associated with BMD in children under 3 years old.

Adverse Impact of Heavy Metals on Bone Cells and Bone Metabolism Dependently and Independently through Anemia

Mounting evidence is revealing that heavy metals can incur disordered bone homeostasis, leading to the development of degenerative bone diseases, including osteoporosis, osteoarthritis, degenerative disk disease, and osteomalacia. Meanwhile, heavy metal-induced anemia has been found to be intertwined with degenerative bone diseases. However, the relationship and interplay among these adverse outcomes remain elusive. Thus, it is of importance to shed light on the modes of action (MOAs) and adverse outcome pathways (AOPs) responsible for degenerative bone diseases and anemia under exposure to heavy metals. In the current Review, the epidemiological and experimental findings are recapitulated to interrogate the contributions of heavy metals to degenerative bone disease development which may be attributable dependently and independently to anemia. A few likely mechanisms are postulated for anemia-independent degenerative bone diseases, including dysregulated osteogenesis and osteoblastogenesis, imbalanced bone formation and resorption, and disturbed homeostasis of essential trace elements. By contrast, remodeled bone microarchitecture, inhibited erythropoietin production, and disordered iron homeostasis are speculated to account for anemia-associated degenerative bone disorders upon heavy metal exposure. Together, this Review aims to elaborate available literature to fill in the knowledge gaps in understanding the detrimental effects of heavy metals on bone cells and bone homeostasis through different perspectives.

Iron Deficiency in Menstruating Adult Women: Much More than Anemia

Background: Iron deficiency anemia (IDA) is highly prevalent in women of child-bearing age. However, their nonhematological symptoms have been overlooked. This study aims to analyze the nonhematological features and symptoms of IDA in a group of women of reproductive age and the changes occurred during iron therapy. Materials and Methods: IDA women underwent dietary, physical activity, menstrual blood loss, and cognitive function assessment at baseline. Hematological and biochemical parameters were analyzed. Executive attention was tested by the flanker task and working memory by the 2-back task. Oral iron therapy (ferrous sulfate) was given to 35 women for 8 weeks and the changes in iron status, biochemical markers, cognitive function, and nonhematological symptoms were evaluated. Results: Patients presented nonhematological symptoms: pica, 32.4%; cheilitis, 20.6%; restless legs syndrome (RLS), 20.6%; diffuse hair loss, 55.9%; and ungual alterations, 38.2%. Two or more symptoms were present in 58.8% of women. Serum iron and working memory were correlated at baseline. Multivariate analyses show associations (odds ratio [OR], 95% confidence interval [CI]) between pica and reaction time in the working memory test (OR 2.14, 95% CI 1.19-3.87, p = 0.012); RLS with total serum protein (OR 0.08, 95% CI 0.06-0.92, p = 0.043); and cheilitis with mean corpuscular hemoglobin (OR 0.388, 95% CI 0.189-0.799, p = 0.01). Pica, cheilitis, and RLS completely resolved with iron therapy, and ungual alterations and hair loss improved in 92.3% and 84.2% of women, respectively. Better performance in executive attention and working memory was observed after iron therapy. Conclusions: More attention should be given to the nonhematological manifestations of IDA to improve the quality of life of menstruating women.

Vitamin D Status in Egyptian Adolescent Females with Iron Deficiency Anemia and Its Correlation with Serum Iron Indices

Background:

In Egypt, it seems that adolescent girls are a candidate for Vitamin D Deficiency (VDD), mostly due to inadequate sun exposure as a result of the culture and social dress codes and dietary factors. Currently, there is growing evidence that VDD is associated with Iron Deficiency Anemia (IDA).

Aim:

To investigate the frequency of VDD in adolescent females with IDA in comparison to healthy control and demonstrate whether VD level was correlated with serum iron indices.

Subjects and Methods:

Forty adolescent females with known cases of IDA (group 1) and 30 healthy females matched for age as a control (group 2) were selected. We compared the differences between the two groups to determine the degree of VD level; where VDD was defined as 25-hydroxyvitamin D [25(OH)D] ≤20 ng/mL, vitamin D insufficiency (VDI) as 25(OH) D of 20-30 ng/mL, and vitamin D sufficiency (VDS) as 25(OH)D >30 ng/mL. Body mass index (BMI), complete blood count (CBC), serum iron, total iron binding capacity (TIBC), serum ferritin, serum creatinine, ionized calcium and 25(OH)D were measured for all participants.

Results:

We found that subnormal vitamin D (VDD and VDI) was more frequent in the IDA group (75%) than control (40%), (p = 0.025); where 19 adolescent female patients (47.5%) were VDD, 11 (27.5%) were VDI and 10 (25%) were VDS, while in the control group, VDD was present in 4 (20%), VDI in 4 (20%) and VDS in 12 (60%) respectively. There was not any significant correlation between serum VD and serum iron indices (r =0.168, p < 0.05) and Hb (r = 0.360, p < 0.001). There was no significant difference in serum hemoglobin level between IDA patients with subnormal VD and those with VDS. The mean level of serum 25(OH) D was significantly lower in winter months than summer in both groups; (16.87 vs. 31.57 mg/dL, p < 0.001) and (31.9 vs. 35.04 mg/dL, p < 0.001) respectively. BMI, Iron, TIBC and seasonal variation were not predictors of 25(OH) D levels in adolescent girls with IDA.

Conclusion:

VDD has a higher frequency in Egyptian adolescent females with IDA than healthy control. However, vitamin D levels were not significantly correlated with iron indices. Our result might direct the attention for measuring vitamin D level in patients with IDA with the possibility of VD supplementation with iron.

The Impact of Trace Minerals on Bone Metabolism

Bone is a metabolically active tissue that responds to alterations in dietary intake and nutritional status. It is ~ 35% protein, mostly collagen which provides an organic scaffolding for bone mineral. The mineral is the remaining ~ 65% of bone tissue and composed mostly of calcium and phosphate in a form that is structurally similar to mineral within the apatite group. The skeletal tissue is constantly undergoing turnover through resorption by osteoclasts coupled with formation by osteoblasts. In this regard, the overall bone balance is determined by the relative contribution of each of these processes. In addition to macro minerals such as calcium, phosphorus, and magnesium which have well-known roles in bone health, trace elements such as boron, iron, zinc, copper, and selenium also impact bone metabolism. Effects of trace elements on skeletal metabolism and tissue properties may be indirect through regulation of macro mineral metabolism, or direct by affecting osteoblast or osteoclast proliferation or activity, or finally through incorporation into the bone mineral matrix. This review focuses on the skeletal impact of the following trace elements: boron, iron, zinc, copper, and selenium, and overviews the state of the evidence for each of these minerals.

The Unexplored Crossroads of the Female Athlete Triad and Iron Deficiency: A Narrative Review

Despite the severity and prevalence of iron deficiency in exercising women, few published reports have explored how iron deficiency interacts with another prevalent and severe condition in exercising women: the 'female athlete triad.' This review aims to describe how iron deficiency may interact with each component of the female athlete triad, that is, energy status, reproductive function, and bone health. The effects of iron deficiency on energy status are discussed in regards to thyroid function, metabolic fuel availability, eating behaviors, and energy expenditure. The interactions between iron deficiency and reproductive function are explored by discussing the potentially impaired fertility and hyperprolactinemia due to iron deficiency and the alterations in iron metabolism due to menstrual blood loss and estrogen exposure. The interaction of iron deficiency with bone health may occur via dysregulation of the growth hormone/insulin-like growth factor-1 axis, hypoxia, and hypothyroidism. Based on these discussions, several future directions for research are presented.

Influence of Iron on Bone Homeostasis

Bone homeostasis is a complex process, wherein osteoclasts resorb bone and osteoblasts produce new bone tissue. For the maintenance of skeletal integrity, this sequence has to be tightly regulated and orchestrated. Iron overload as well as iron deficiency disrupt the delicate balance between bone destruction and production, via influencing osteoclast and osteoblast differentiation as well as activity. Iron overload as well as iron deficiency are accompanied by weakened bones, suggesting that balanced bone homeostasis requires optimal-not too low, not too high-iron levels. The goal of this review is to summarize our current knowledge about how imbalanced iron influence skeletal health. Better understanding of this complex process may help the development of novel therapeutic approaches to deal with the pathologic effects of altered iron levels on bone.

The Association between Iron and Vitamin D Status in Female Elite Athletes

Vitamin D may influence iron metabolism and erythropoiesis, whereas iron is essential for vitamin D synthesis. We examined whether vitamin D deficiencies (VDD) are associated with reduced iron status and whether progressive iron deficiency (ID) is accompanied by inferior vitamin D status. The study included 219 healthy female (14–34 years old) athletes. VDD was defined as a 25(OH)D concentration < 75 nmol/L. ID was classified based on ferritin, soluble transferrin receptor (sTfR), total iron binding capacity (TIBC) and blood morphology indices. The percentage of ID subjects was higher (32%) in the VDD group than in the 25(OH)D sufficient group (11%) (χ² = 10.6; p = 0.001). The percentage of VDD subjects was higher (75%) in the ID than in the normal iron status group (48%) (χ² = 15.6; p = 0.001). The odds ratios (ORs) for VDD increased from 1.75 (95% CI 1.02–2.99; p = 0.040) to 4.6 (95% CI 1.81–11.65; p = 0.001) with progressing iron deficiency. ID was dependent on VDD in both VDD groups (25(OH)D < 75 and < 50 nmol/L). The ID group had a lower 25(OH)D concentration (p = 0.000). The VDD group had lower ferritin (p = 0.043) and iron (p = 0.004) concentrations and higher values of TIBC (p = 0.016) and sTfR (p = 0.001). The current results confirm the association between vitamin D and iron status in female athletes, although it is difficult to assess exactly which of these nutrients exerts a stronger influence over the other.

Vitamin D deficiency and anemia risk in children: a review of emerging evidence

There has been renewed scientific interest in the sequelae of vitamin D deficiency, given the emerging evidence on the diverse biologic functions of vitamin D, besides its fundamental role in bone and mineral metabolism. For the past decade, the evidence in the medical literature pointing to a relationship between anemia risk and vitamin D deficiency has been accumulating. This paper critically reviews the current evidence linking vitamin D deficiency to anemia risk in children. The synthesized evidence indicates that the studies, which were preponderantly conducted among the adult population, not only reported a bidirectional relationship between vitamin D deficiency and anemia but also showed a racial effect. In studies conducted among children, similar results were reported. Although the causal association of vitamin D deficiency with anemia risk (especially iron-deficiency anemia) remains debatable, the noncalcemic actions of the vitamin and its analogs hold prospects for several novel clinical applications. There is, however, unanimity in many reports suggesting that vitamin D deficiency is directly associated with anemia of chronic disease or inflammation. Despite the advances in unraveling the role of vitamin D in iron homeostasis, further research is still required to validate causality in the relationship between vitamin D deficiency and anemia, as well as to determine its optimal dosing, the ideal recipients for therapeutic intervention, and the preferred analogs to administer.

Trace elements have beneficial, as well as detrimental effects on bone homeostasis

The protective role of nutrition factors such as calcium, vitamin D and vitamin K for the integrity of the skeleton is well understood. In addition, integrity of the skeleton is positively influenced by certain trace elements (e.g. zinc, copper, manganese, magnesium, iron, selenium, boron and fluoride) and negatively by others (lead, cadmium, cobalt). Deficiency or excess of these elements influence bone mass and bone quality in adulthood as well as in childhood and adolescence. However, some protective elements may become toxic under certain conditions, depending on dosage (serum concentration), duration of treatment and interactions among individual elements. We review the beneficial and toxic effects of key elements on bone homeostasis.

Effects of Iron on Vitamin D Metabolism: A Systematic Review

Vitamin D is a prohormone nutrient, which is involved in skeletal and extra-skeletal functions. Iron is another essential nutrient that is necessary for the production of red blood cells and oxygen transport. This element plays important roles in enzymatic systems including those required for Vitamin D activation. To the best of our knowledge, there is no exclusive review on the relationship between iron deficiency anemia (IDA), as the most prevalent type of anemia, and Vitamin D deficiency and the effect of recovery from iron deficiency on Vitamin D status. The aim of this study was to conduct a systematic search of observational and clinical trials in this field. The databases of PubMed, ProQuest, Cochrane Library, ISI Web of Knowledge, and SCOPUS were searched comprehensively. English-language human studies conducted on iron deficient patients or interventions on the effect of iron therapy on Vitamin D were extracted (n = 10). Our initial search yielded 938 articles. A total of 23 papers met the inclusion criteria. Thirteen studies were excluded because they were not relevant or not defining anemia types. The final analysis was performed on ten articles (3 cross-sectional and 7 interventional studies). Observational data indicated a positive relationship between iron status and Vitamin D, while trials did not support the effectiveness of iron supplementation on improving Vitamin D status. The mechanism underlying this association may involve the reduction of the activation of hydroxylases that yield calcitriol. Future randomized controlled trials with large sample sizes and proper designs are needed to highlight underlying mechanisms.

Effect of vitamin D3 supplementation on iron status: a randomized, double-blind, placebo-controlled trial among ethnic minorities living in Norway

BACKGROUND

Both vitamin D and iron deficiencies are widespread globally, and a relationship between these deficiencies has been suggested. However, there is a paucity of randomised controlled trials assessing the effect of vitamin D supplementation on iron status.

PURPOSE

We aimed to investigate whether 16 weeks of daily vitamin D3 supplementation had an effect on serum ferritin, haemoglobin, serum iron and transferrin saturation.

METHODS

Overall, 251 participants from South Asia, Middle East and Africa aged 18-50 years who were living in Norway were randomised to receive daily oral supplementation of 10 μg vitamin D3, 25 μg vitamin D3, or placebo for 16 weeks during the late winter. Blood samples from baseline and after 16 weeks were analysed for serum 25-hydroxyvitamin D (s-25(OH) D), serum ferritin, haemoglobin and serum iron. In total, 214 eligible participants completed the intervention (86 % of those randomised). Linear regression analysis were used to test the effect of vitamin D3 supplementation combined (10 or 25 μg) and separate doses 10 or 25 μg compared to placebo on change (T2-T1) in each outcome variable adjusted for baseline s-25(OH)D values.

RESULTS

There was no difference in change in the levels of s-ferritin (1.9 μg/L, 95 % CI: -3.2, 7.0), haemoglobin (-0.02 g/dL, 95 % CI: -0.12, 0.09), s-iron (0.4 μg/L, 95 % CI: -0.5, 1.3) or transferrin saturation (0.7 %, 95 % CI: -0.6.1, 2.0) between those receiving vitamin D3 or those receiving placebo. Serum 25-hydroxyvitamin D increased from 29 nmol/L at baseline to 49 nmol/L after the intervention, with little change in the placebo group.

CONCLUSIONS

In this population of healthy ethnic minorities from South Asia, the Middle East and Africa who had low vitamin D status, 16 weeks of daily supplementation with 10 or 25 μg of vitamin D3 did not significantly affect the haemoglobin levels or other markers of iron status.

Iron Chelation Inhibits Osteoclastic Differentiation In Vitro and in Tg2576 Mouse Model of Alzheimer's Disease

Patients of Alzheimer's disease (AD) frequently have lower bone mineral density and higher rate of hip fracture. Tg2576, a well characterized AD animal model that ubiquitously express Swedish mutant amyloid precursor protein (APPswe), displays not only AD-relevant neuropathology, but also age-dependent bone deficits. However, the underlying mechanisms remain poorly understood. As APP is implicated as a regulator of iron export, and the metal chelation is considered as a potential therapeutic strategy for AD, we examined iron chelation's effect on the osteoporotic deficit in Tg2576 mice. Remarkably, in vivo treatment with iron chelator, clinoquinol (CQ), increased both trabecular and cortical bone-mass, selectively in Tg2576, but not wild type (WT) mice. Further in vitro studies showed that low concentrations of CQ as well as deferoxamine (DFO), another iron chelator, selectively inhibited osteoclast (OC) differentiation, without an obvious effect on osteoblast (OB) differentiation. Intriguingly, both CQ and DFO's inhibitory effect on OC was more potent in bone marrow macrophages (BMMs) from Tg2576 mice than that of wild type controls. The reduction of intracellular iron levels in BMMs by CQ was also more dramatic in APPswe-expressing BMMs. Taken together, these results demonstrate a potent inhibition on OC formation and activation in APPswe-expressing BMMs by iron chelation, and reveal a potential therapeutic value of CQ in treating AD-associated osteoporotic deficits.

Chronic iron deficiency as an emerging risk factor for osteoporosis: a hypothesis

Iron is essential in oxygen transport and participates in many enzymatic systems in the body, with important roles in collagen synthesis and vitamin D metabolism. The relationship between iron and bone health comes from clinical observations in iron overload patients who suffered bone loss. The opposite scenario—whether iron deficiency, with or without anemia, affects bone metabolism—has not been fully addressed. This is of great interest, as this nutrient deficiency is a worldwide public health problem and at the same time osteoporosis and bone alterations are highly prevalent. This review presents current knowledge on nutritional iron deficiency and bone remodeling, the biomarkers to evaluate iron status and bone formation and resorption, and the link between iron and bone metabolism. Finally, it is hypothesized that chronic iron deficiency induces bone resorption and risk of osteoporosis, thus complete recovery from anemia and its prevention should be promoted in order to improve quality of life including bone health. Several mechanisms are suggested; hence, further investigation on the possible impact of chronic iron deficiency on the development of osteoporosis is needed.

High dose intravenous iron, mineral homeostasis and intact FGF23 in normal and uremic rats

BACKGROUND

High iron load might have a number of toxic effects in the organism. Recently intravenous (iv) iron has been proposed to induce elevation of fibroblast growth factor 23 (FGF23), hypophosphatemia and osteomalacia in iron deficient subjects. High levels of FGF23 are associated with increased mortality in the chronic kidney disease (CKD) population. CKD patients are often treated with iv iron therapy in order to maintain iron stores and erythropoietin responsiveness, also in the case of not being iron depleted. Therefore, the effect of a single high iv dose of two different iron preparations, iron isomaltoside 1000 (IIM) and ferric carboxymaltose (FCM), on plasma levels of FGF23 and phosphate was examined in normal and uremic iron repleted rats.

METHODS

Iron was administered iv as a single high dose of 80 mg/kg bodyweight and the effects on plasma levels of iFGF23, phosphate, Ca2+, PTH, transferrin, ferritin and iron were examined in short and long term experiments (n = 99). Blood samples were obtained at time 0, 30, 60, 180 minutes, 24 and 48 hours and in a separate study after 1 week. Uremia was induced by 5/6-nephrectomy.

RESULTS

Nephrectomized rats had significant uremia, hyperparathyroidism and elevated FGF23. Iron administration resulted in significant increases in plasma ferritin levels. No significant differences were seen in plasma levels of iFGF23, phosphate and PTH between the experimental groups at any time point within 48 hours or at 1 week after infusion of the iron compounds compared to vehicle.

CONCLUSIONS

In non-iron depleted normal and uremic rats a single high dose of either of two intravenous iron preparations, iron isomaltoside 1000, and ferric carboxymaltose, had no effect on plasma levels of iFGF23 and phosphate for up to seven days.

Changes in blood pressure and lipid levels in young women consuming a vitamin D-fortified skimmed milk: a randomised controlled trial

Vitamin D exerts a variety of extra-skeletal functions.

AIM

to know the effects of the consumption of a vitamin D-fortified skimmed milk on glucose, lipid profile, and blood pressure in young women.

METHODS

a randomised, placebo-controlled, double-blind parallel-group trial of 16 weeks duration was conducted in young women with low iron stores who consumed a skimmed milk fortified with iron and 200 IU/day (5 μg) of vitamin D (D-fortified group, n = 55), or a placebo without vitamin D (D-placebo group, n = 54). A reference group (n = 56) of iron-sufficient women was also recruited.

RESULTS

baseline serum 25-hydroxyvitamin D was inversely correlated with total-cholesterol (r = -0.176, p = 0.023) and low density lipoprotein-cholesterol (LDL-chol) (r = -0.176, p = 0.024). During the assay, LDL-cholesterol increased in the D-placebo group (p = 0.005) while it tended to decrease in the D-fortified group (p = 0.07). Neither group displayed changes in total-cholesterol, high density lipoprotein-cholesterol (HDL-chol), triglycerides or glucose levels. Systolic (p = 0.017) and diastolic (p = 0.010) blood pressure decreased during the assay in the D-fortified group without significant differences compared to the D-placebo.

CONCLUSION

consumption of a dairy product fortified with vitamin D reduces systolic and diastolic blood pressure but does not change lipid levels in young women.