Zinc supplementation increases bone alkaline phosphatase in healthy men

Enhanced Mechanical Properties, Corrosion Resistance, Cytocompatibility, Osteogenesis, and Antibacterial Performance of Biodegradable Mg-2Zn-0.5Ca-0.5Sr/Zr Alloys for Bone-Implant Application

Magnesium (Mg) alloys are widely used in bone fixation and bone repair as biodegradable bone-implant materials. However, their clinical application is limited due to their fast corrosion rate and poor mechanical stability. Here, the development of Mg-2Zn-0.5Ca-0.5Sr (MZCS) and Mg-2Zn-0.5Ca-0.5Zr (MZCZ) alloys with improved mechanical properties, corrosion resistance, cytocompatibility, osteogenesis performance, and antibacterial capability is reported. The hot-extruded (HE) MZCZ sample exhibits the highest ultimate tensile strength of 255.8 ± 2.4 MPa and the highest yield strength of 208.4 ± 2.8 MPa and an elongation of 15.7 ± 0.5%. The HE MZCS sample shows the highest corrosion resistance, with the lowest corrosion current density of 0.2 ± 0.1 µA cm-2 and the lowest corrosion rate of 4 ± 2 µm per year obtained from electrochemical testing, and a degradation rate of 368 µm per year and hydrogen evolution rate of 0.83 ± 0.03 mL cm-2 per day obtained from immersion testing. The MZCZ sample shows the highest cell viability in relation to MC3T3-E1 cells among all alloy extracts, indicating good cytocompatibility except at 25% concentration. Furthermore, the MZCZ alloy shows good antibacterial capability against Staphylococcus aureus.

Recent Trends in Hydroxyapatite Supplementation for Osteoregenerative Purposes

Bone regeneration has gained attention in the biomedical field, which has led to the development of materials and synthesis methods meant to improve osseointegration and cellular bone activity. The properties of hydroxyapatite, a type of calcium phosphate, have been researched to determine its advantages for bone tissue engineering, particularly its biocompatibility and ability to interact with bone cells. Recently, the advantages of utilizing nanomolecules of hydroxyapatite, combined with various substances, in order to enhance and combine their characteristics, have been reported in the literature. This review will outline the cellular and molecular roles of hydroxypatite, its interactions with bone cells, and its nano-combinations with various ions and natural products and their effects on bone growth, development, and bone repair.

Aberrance of Zinc Metalloenzymes-Induced Human Diseases and Its Potential Mechanisms

Zinc, an essential micronutrient in the human body, is a component in over 300 enzymes and participates in regulating enzymatic activity. Zinc metalloenzymes play a crucial role in physiological processes including antioxidant, anti-inflammatory, and immune responses, as well as apoptosis. Aberrant enzyme activity can lead to various human diseases. In this review, we summarize zinc homeostasis, the roles of zinc in zinc metalloenzymes, the physiological processes of zinc metalloenzymes, and aberrant zinc metalloenzymes in human diseases. In addition, potential mechanisms of action are also discussed. This comprehensive understanding of the mechanisms of action of the regulatory functions of zinc in enzyme activity could inform novel zinc-micronutrient-supply strategies for the treatment of diseases.

Is Zinc an Important Trace Element on Bone-Related Diseases and Complications? A Meta-analysis and Systematic Review from Serum Level, Dietary Intake, and Supplementation Aspects

Bone-related diseases are very common problems, especially in the elderly population. Zinc takes part in the growth and maintenance of healthy bones. This meta-analysis aims to evaluate the effects of zinc supplementation or dietary zinc intake on serum zinc levels and bone turnover markers. A systematical research was performed with 2899 articles in PubMed, WoS, and Scopus for relevant articles in English which have mean/standard deviation values of serum zinc levels, dietary zinc intake/zinc supplementation (mg/day), and bone turnover markers up to February 2020. In the overall analysis, serum zinc level was significantly lower in patients with osteoporosis compared with controls (p 0.0002). Dietary zinc intake decreased in the fracture group compared with controls according to subgroup analysis patients with fracture (p 0.02). Zinc supplementation was effective on the femoral neck (p < 0.0001) and lumbar spine (p 0.05) bone mineral density (BMD). In the correlation analysis of the data obtained from all of the included studies, serum osteocalcin (p 0.0106, r - 0.9148) correlated with serum zinc level. In conclusion, serum zinc level and dietary zinc intake could have an essential role in preventing osteoporosis. Zinc supplementation might improve bone turnover markers for bone formation such as serum osteocalcin and serum alkaline phosphatase and also, BMD at the site of the femoral neck.

Chocolate and chocolate constituents influence bone health and osteoporosis risk

Bone loss resulting in increased risk for osteoporosis is a major health issue worldwide. Chocolate is a rich source of antioxidant and antiinflammatory flavonoids and dietary minerals with the potential to benefit bone health. However, other chocolate constituents such as cocoa butter, sugar, and methylxanthines may be detrimental to bone. Human studies investigating the role of chocolate consumption on serum bone markers and bone mineral density (BMD) have been inconsistent. A contributing factor is likely the different composition and thereby the nutrient and bioactive content among chocolate types. White and milk chocolate are high in sugar and low in flavonoids and most minerals. Dark chocolate (45-85% cocoa solids) is high in flavonoids, most minerals, and low in sugar with ≥70% cocoa solids resulting in higher fat and methylxanthine content. The aim of this review was to examine the relationship between chocolate consumption and its constiuents, including flavonoid content, on bone health and osteoporosis risk. Studies showed postmenopausal women had no bone effects at moderate chocolate intakes, whereas adolescents consuming chocolate had greater longitudinal bone growth. Based on flavonoid and mineral content, unsweetened cocoa powder appeared to be the best option followed by dark chocolate with higher cocoa content in terms of supporting and preserving bone health. Determining dietary recommendations for chocolate consumption relative to bone health is important because of the growing popularity of chocolate, particularly dark chocolate, and an expected increase in consumption owing to suggestions of health benefits against various degenerative diseases.

Effects of dietary dosage forms of copper supplementation on growth, antioxidant capacity, innate immunity enzyme activities and gene expressions for juvenile Litopenaeus vannamei

The experiment was conducted to evaluate the effects of different dietary dosage forms of copper supplementation on growth performance, hematological characteristics, antioxidant capacity, immune responses and gene expressions related to innate immune of juvenile Pacific white shrimp Litopenaeus vannamei. Three isonitrogenous and isolipidic diets were formulated to contain three dosage forms of copper: copper sulfate (Diet I-Cu), copper sulfate + copper amino acid complex (1: 1, Diet M-Cu) and copper amino acid complex from Availa^®Cu100 (Diet Availa-Cu), respectively. 360 Pacific white shrimp juveniles (initial weight 1.86 ± 0.03 g) were randomly allocated in 12 tanks corresponding to quadruplicate tanks of the three dietary treatments, and the 8-week feeding trail was conducted. The results indicated that percent weight gain (PWG) and specific growth rate (SGR) in shrimp fed M-Cu diet were significantly higher than that fed I-Cu diet. Survival, feed efficiency (FE), protein efficiency ratio (PER) of shrimp were not significantly different between all treatment groups. High contents of total protein (TP) and glucose (GLU) were found in shrimp fed the diet containing M-Cu, whereas contents of cholesterol (CHOL) and triacylglycerol (TAG) in shrimp fed M-Cu diet were significantly lower than that in I-Cu diet group. In hemolymph, shrimp fed M-Cu diet had high activities of phenoloxidase (PO), alkaline phosphatase (ALP) and acid phosphatase (ACP). While, Cu/Zn superoxide dismutase (Cu/Zn SOD), ceruloplasmin (CP) and lysozyme (LZM) in hemolymph were not significantly affected by different dietary dosage forms of copper. High activities of Cu/Zn SOD, ALP, ACP and LZM in hepatopancreas were observed in shrimp fed M-Cu diet. Shrimp fed diet supplemented with Availa-Cu showed a significantly higher gene expression levels of Cu/Zn sod, alp, acp and lzm in hepatopancreas than that fed I-Cu diet. This study indicated that copper amino acid complex was more effective than copper sulfate to improve growth performance and enhance antioxidant ability and innate immune system.

Low Alkaline Phosphatase (ALP) In Adult Population an Indicator of Zinc (Zn) and Magnesium (Mg) Deficiency

Alkaline Phosphatase (ALP) enzyme activity is usually measured as a part of liver function test (LFT) to detect increases in its activity. Less attention has been put to know the conditions associated with decreases in its activity. Micronutrients like Zinc (Zn) and Magnesium (Mg) are important causes of low ALP activity. Our Objective is to find out Zn and Mg deficiencies as important cause of decrease in ALP activity and to initiate supplementation of these minerals. The study was done to assess Zn and Mg deficiency in 42 persons having low ALP activity and 45 healthy controls. Correlation between minerals and ALP activities were also carried out. It was found that 52.38% of cases are Mg deficient and 47.62% cases are Zn deficient. A significant decrease in Zn and Mg was observed in low ALP cases when compared with control (p<0.001, p<0.05). Significant positive correlation was found between the minerals and ALP. Serum Zn and Mg are essential for human body and by screening their deficiency, supplementation of minerals can be initiated.

Facile microwave-assisted synthesis of Te-doped hydroxyapatite nanorods and nanosheets and their characterizations for bone cement applications

In this work, the authors have fabricated the nanorods and nanosheets of pure and Te-doped HAp with different Te concentrations (0.04, 0.08, 0.16, 0.24wt%) by microwave-assisted technique at low temperature. The crystallite size, degree of crystallinity and lattice parameters are calculated. FE-SEM study confirms that the fabricated nanostructures are nanorods of diameter about 10nm in undoped and at low concentration of Te doping. However, at and higher concentration, it becomes nanosheets of about 5nm thickness. X-ray diffraction, FT-IR and FT-Raman studies shows that the prepared products are of HAp and Te has been successfully incorporated. From EDX the Ca/P molar ratio of the pure HAp is about 1.740, while this ratio for 0.04, 0.08, 0.16, 0.24 wt% Te doped is about 1.53, 1.678, 1.724, 1.792, respectively. Crystallite size was found to be increased with Te doping from 15nm to 62nm. The value of dielectric constant is found to be enhanced at higher concentrations of Te. The values of linear absorption coefficient were also determined and show that the prepared material with Te doping is more absorbable than pure and will be highly applicable in radiation detection applications. Furthermore, the antimicrobial potential of pure and Te doped HAp was examined against some Gram- negative and positive bacteria and fungi by agar disk diffusion method. The results demonstrated that the antimicrobial activity of Te doped HAp is stronger than that of pure HAp where it exhibited the highest activity against Bacillus subtilis>Candida albicans>Shigella dysenteriae.

Effects of thirty elements on bone metabolism

The human skeleton, made of 206 bones, plays vital roles including supporting the body, protecting organs, enabling movement, and storing minerals. Bones are made of organic structures, intimately connected with an inorganic matrix produced by bone cells. Many elements are ubiquitous in our environment, and many impact bone metabolism. Most elements have antagonistic actions depending on concentration. Indeed, some elements are essential, others are deleterious, and many can be both. Several pathways mediate effects of element deficiencies or excesses on bone metabolism. This paper aims to identify all elements that impact bone health and explore the mechanisms by which they act. To date, this is the first time that the effects of thirty minerals on bone metabolism have been summarized.

Effect of zinc supplementation on bone formation in hemodialysis patients with normal or low turnover bone

Zinc (Zn) is an essential trace element, which has been shown to stimulate osteoblastic bone formation and to inhibit osteoclastic bone resorption in vitro. In thalassemia, major patients Zn supplementation was reported to increase whole-body bone mineral content and areal bone mineral density. Therefore, we investigated the effect of Zn supplementation on bone formation in hemodialysis (HD) patients. Nine male patients with age of 66 (35-78) years indicated by median (range), HD vintage of 57 (4-97) months and serum intact parathyroid hormone (PTH) of 113 (6-310) pg/mL were supplemented with polaprezinc containing 34 mg Zn/day for 18 months. Doses of vitamin D were not changed during supplementation. Blood was collected at baseline, 3, 6, 12 and 18 months. Serum Zn increased significantly from 58 (52-65) μg/dL to 71 (57-93) μg/dL at three months and remained unchanged until 18 months. No changes were observed in serum intact PTH during supplementation. Although we found no changes in serum bone alkaline phosphatase (BAP) during Zn supplementation analyzed by Friedman test and Scheffe post hoc test, a significant trend of increase in serum BAP was verified by Jonckheere-Terpstra test (p = 0.0409). On the contrary, there was no trend in serum TRACP5b by Jonckheere-Terpstra test. Therefore, we suggested the effect of Zn supplementation on promoting bone formation, not affected by the status of PTH and vitamin D, in HD patients with normal or low turnover bone.

Zinc supplementation does not alter sensitive biomarkers of copper status in healthy boys

The tolerable upper intake levels (UL) for zinc for children were based on limited data and there is concern that the UL may be set too low. The first effect of excessive zinc intake is a reduction in copper status. The primary objective of this study was to examine the effect of zinc supplementation on copper status in children. Healthy, 6- to 8-y-old boys from Ontario, Canada were assigned to take a placebo (n = 10) or 5 mg (n = 10), 10 mg (n = 9), or 15 mg (n = 8) of zinc supplement daily for 4 mo in a double-blinded, placebo-controlled, randomized trial. Biochemical measures were evaluated at baseline and after 2 and 4 mo of supplementation. Food records were completed near the baseline and 4-mo visits. Age and anthropometric measurements did not differ (P > 0.05) between treatment groups at baseline. Mean zinc intakes from food alone (10.9-14.8 mg zinc/d) approached or exceeded the UL of 12 mg/d. Compared with the placebo group, the zinc groups had a greater change in the urine zinc:creatinine ratio at 4 mo (P = 0.02). Traditional (plasma copper and ceruloplasmin activity) and more sensitive biomarkers of copper status, including erythrocyte SOD1 activity and the erythrocyte CCS:SOD1 protein ratio, were unchanged in zinc-supplemented boys, demonstrating that copper status was not depressed. Serum lipid measures and hemoglobin concentrations were also unaffected and gastrointestinal symptoms were not reported. These data provide evidence in support of the need for reexamining the current UL for zinc for children.

Oral zinc supplementation does not improve oxidative stress or vascular function in patients with type 2 diabetes with normal zinc levels

OBJECTIVE

There is considerable controversy about what constitutes optimal zinc intakes in patients with type 2 diabetes mellitus. Several studies suggest that higher zinc intakes improve vascular function and decrease oxidative damage. We aimed to assess the effects of zinc supplementation using a range of reliable biomarkers of oxidative damage and vascular function in patients with type 2 diabetes.

METHODS

Forty male type 2 diabetic patients were supplemented either with 240 mg/day of zinc as zinc gluconate (n=20) or with placebo (n=20) for 3 months. Blood and spot urine samples were taken at baseline, days 3 and 7, months 1, 2 and 3 during supplementation and 1 month after cessation. Serum zinc, reliable biomarkers of oxidative damage (F(2)-isoprostanes, neuroprostanes, cholesterol oxidation products, allantoin) as well as hydroxyeicosatetraenoic acid products and vascular-related indices (augmentation index, pulse wave velocity and aortic pressure) were measured.

RESULTS

Despite significantly higher levels of serum zinc in the treatment group, markers of oxidative damage, levels of hydroxyeicosatetraenoic acid products and vascular indices were unchanged by zinc supplementation during the four-month study period.

CONCLUSION

Improving the zinc status in patients with type 2 diabetes with normal zinc levels did not have any impact on oxidative damage and vascular function, and such supplementation may not be generally beneficial in these individuals.

Determinants of serum zinc concentrations in a population of French middle-age subjects (SU.VI.MAX cohort)

BACKGROUND/OBJECTIVES

Few studies have been conducted on determinants of serum zinc concentration, especially in France. The aim of this study was to investigate the relationships between serum zinc concentrations, and age, education, living area and life style in a large sample cohort of French adults.

SUBJECTS/METHODS

Blood samples were collected after 12-h fasting in French adults (7448 women, 35-65 years old and 4926 men, 45-65 years old) participating to the SUpplementation in AntioXidant VItamins and Minerals cohort at enrolment. Serum zinc was determined by flame atomic absorption.

RESULTS

Serum zinc concentration was lower in women (mean: 12.9 μmol/l, 95% confidence interval: 9.2-16.6 μmol/l) compared with men (mean: 13.4 μmol/l, 95% confidence interval: 9.7-17.1 μmol/l, P<0.0001). In total, 10% of the women showed serum zinc values <10.7 μmol/l and 10% of the men showed serum zinc values <11.3 μmol/l. Age was negatively associated with serum zinc only in men (P=0.001). In women, a positive association between smoking and serum zinc concentration (P=0.0003), and a negative relationship between highest education level and serum zinc concentration (P=0.01) were observed. With regard to geographical areas, the highest serum zinc concentrations were found in the Center, and the lowest in the Southwest of France for both men and women. The association between serum zinc concentrations and food categories or macronutrient intake disappeared after stratifying by gender.

CONCLUSIONS

Age, gender and geographic area seem the main determinants of serum zinc concentrations in this study.

Mechanism of Zn stabilization in hydroxyapatite and hydrated (0 0 1) surfaces of hydroxyapatite

A basic understanding of Zn incorporation on bulk and hydrated (0 0 1) surfaces of hydroxyapatite (HA) is attained through electronic structure calculations which use a combined first principles density functional (DFT) and extended Hückel tight binding (EHTB) methodology. A Zn substituted hydroxyapatite relaxed structure is obtained through a periodic cell DFT geometry optimization method. Electronic structure properties are calculated by using both cluster DFT and periodic cell EHTB methods. Bond order calculations show that Zn preference for the Ca2 vacancy, near the OH channel and with greater structural flexibility, is associated with the formation of a four-fold (bulk) and nearly four-fold (surface) coordination, as in ZnO. When occupying the octahedral Ca1 vacancy, Zn remains six-fold in the bulk, but coordination decreases to five-fold in the surface. In the bulk and surface, Zn2 is found to be more covalent than Zn1, due to a decrease in bond lengths at the four-fold site, which approach the 1.99 Å ZnO value. Zn is however considerably less bound in the biomaterial than in the oxide, where calculated bond orders are twice as large as in HA. Surface phosphate groups (PO(4)) and hydroxide ions behave as compact individual units as in the bulk; no evidence is found for the presence of HPO(4). Ca-O bond orders decrease at the surface, with a consequent increase in ionicity. Comparison between DFT and EHTB results show that the latter method gives a good qualitative account of charge and bonding in these systems.

The optimum zinc content in set calcium phosphate cement for promoting bone formation in vivo

The final aim of our study is to develop a novel calcium phosphate cement based on zinc-containing α-tricalcium phosphate (αZnTCP) and evaluate its potential as bonegraft material in vivo. In the present study, in vivo efficacy of zinc in hardened bodies of αZnTCP was explored. The hardened bodies prepared from αZnTCP with zinc content of 0.00, 0.04, 0.08, 0.11 and 0.19 wt % were prepared by mixing pure αTCP or αZnTCP powder with 12 wt% sodium succinate solution at a solid-to-liquid ratio of 2.0. Due to the release of zinc ions into the physiological salt solution during curing, the zinc content in the hardened bodies was calculated to be 0.00, 0.03, 0.06, 0.10 and 0.18 wt%, respectively. The hardened bodies were implanted in the femora and tibia of white rabbits for 4 weeks. Histological and histomorphometric evaluation showed that the hardened body containing 0.03 wt% zinc, significantly promoted more new bone formation without evoking adverse tissue reactions than that without zinc. The hardened bodies containing 0.06 and 0.10 wt% zinc also resulted in the increase in numbers of active osteoblasts surrounding the new bone but caused inflammation at the implant sites. Results of this study indicate that the hardened body prepared with αZnTCP is superior to that prepared with αTCP in promoting new bone formation due to the release of zinc ions. This study also indicates that the optimum amount of zinc in the hardened body is about 0.03 wt % to avoid inflammatory reaction.

Burn-induced oxidative stress is altered by a low zinc status: kinetic study in burned rats fed a low zinc diet

As an initial subdeficient status of zinc, considered as an essential antioxidant trace element, is frequent in burned patients, we aim to assess the effects of low zinc dietary intakes on burn-induced oxidative stress, in an animal model. After 8 weeks of conditioning diets containing 80 ppm (control group) or 10 ppm of zinc (depleted group), Wistar rats were 20% TBSA burned and sampled 1-10 days after injury. Kinetic evolutions of zinc status, plasma oxidative stress parameters, and antioxidant enzymes were also studied in blood and organs. The zinc-depleted diet induced, before injury, a significant decrease in zinc bone level and the increase of oxidative stress markers without stimulation of antioxidant enzyme activity. After burn, more markedly in zinc depleted animals than in controls, zinc levels decreased in plasma and bone, while increasing in liver. The decrease of thiol groups and GSH/GSSG ratio and the depression of GPx activity in liver are also moderately emphasized. Nevertheless, depleted zinc status could not be considered as determining for oxidative damages after burn injury. Further investigations must also be done to enlighten the mechanism of beneficial effects of zinc supplementation reported in burned patients.

Zinc deficiency negatively affects alkaline phosphatase and the concentration of Ca, Mg and P in rats

Zn is an essential nutrient that is required in humans and animals for many physiological functions, including immune and antioxidant function, growth, and reproduction. The present study evaluated whether Zn deficiency would negatively affect bone-related enzyme, ALP, and other bone-related minerals (Ca, P and Mg) in rats. Thirty Sprague Dawley rats were assigned to one of the three different Zn dietary groups, such as Zn adequate (ZA, 35 mg/kg), pair fed (PF, 35 mg/kg), Zn deficient (ZD, 1 mg/kg) diet, and fed for 10 weeks. Food intake and body weight were measured daily and weekly, respectively. ALP was measured by spectrophotometry and mineral contents were measured by inductively coupled plasma-mass spectrophotometer (ICP-MS). Zn deficient rats showed decreased food intake and body weight compared with Zn adequate rats (p<0.05). Zn deficiency reduced ALP activity in blood (RBC, plasma) and the tissues (liver, kidney and small intestine) (p<0.05). Also, Zn deficiency reduced mineral concentrations in rat tissues (Ca for muscle and liver, and Mg for muscle and liver) (p<0.05). The study results imply the requirement of proper Zn nurture for maintaining bone growth and formation.

Zinc status and bone mineralisation in adolescent girls

The aim of the project was to assess the relationship between zinc status and bone mineralisation in pre-menarcheal adolescent girls. One hundred and thirty-nine healthy pre-menarcheal girls (Tanner pubic hair stage < or = 4), aged 12.4 +/- 1.0 years, had two visits at an interval of 2 years. Serum and urine zinc concentrations (Zn S; Zn U; Zn U/ creatinine), insulin-like growth factor 1 (IGF-I), and markers of bone turn-over, i.e. osteocalcin and parathormone (PTH), concentrations were measured at the first visit. Lumbar (L2-L4) bone mineral content and density (BMC, BMD) were measured at both visits. BMC and BMD and their increase at the follow-up after 2 years were compared with biochemical data by multiple regression. The stage of puberty was added as a covariable in the analysis. At the first visit, a significant correlation was found between sexual maturity and initial BMC, BMD, height, weight, and IGF-I. Zn S was negatively correlated with osteocalcin. Zn U showed a positive correlation with BMC, BMD, IGF-I, height, weight, and PTH. At the second visit, sexual maturity showed a positive correlation with BMD and weight increments and a negative one with BMC and height gains. Zn S was significantly related with BMD increase. These correlations suggest that zinc plays a role in normal growth and bone mineralisation during puberty onset.