The histological effects of copper and zinc on chick embryo skeletal tissues in organ culture

The impact of copper on bone metabolism

Copper is an essential trace element for the human body. Abnormalities in copper metabolism can lead to bone defects, mainly by directly affecting the viability of osteoblasts and osteoclasts and their bone remodeling function, or indirectly regulating bone metabolism by influencing enzyme activities as cofactors. Copper ions released from biological materials can affect osteoblasts and osteoclasts, either directly or indirectly by modulating the inflammatory response, oxidative stress, and rapamycin signaling. This review presents an overview of recent progress in the impact of copper on bone metabolism. Translational potential of this article: The impact of copper on bone metabolism can provide insights into clinical application of copper-containing supplements and biomaterials.

Metabolic bone disease heralding the diagnosis of Wilson's disease

We report a short-statured, young man in his 20s presenting with bilateral cataract, recurrent kidney stones, history of refractory rickets and bone deformity. He had been consuming calcium and vitamin D supplements and had been operated for cataract and renal stone disease, prior to reporting in our clinic without any significant laboratory or clinical improvement. The patient was diagnosed as having Fanconi's syndrome attributable to Wilson's disease. This patient highlights that in case of resistant rickets, a high index of suspicion must be invoked for Wilson's disease. Timely recognition of this entity results in prompt ministrations and prevention of disability.

Trace Metal Accumulation in Eggs of Wild Nile Crocodiles (Crocodylus niloticus) from Lake St Lucia, South Africa: Implications for Biomonitoring in a Global Biodiversity Hotspot

Nile crocodiles (Crocodylus niloticus) at Lake St Lucia, South Africa, have some of the highest blood lead (Pb) concentrations ever recorded in wildlife globally. Although exposure to Pb is known to pose major risks to wildlife reproductive success, potential impacts on crocodile reproduction at Lake St Lucia have yet to be examined. In this study, we investigated the accumulation of Pb and other trace metals (Al, V, Cr, Co, Cu, Ni, Zn and Cd) in eggs (n = 20) collected from five wild crocodile nests at Lake St Lucia. All metals analysed in this study were detected in egg contents, although concentrations varied considerably among nests and within clutches. Lead was detected in the contents of all eggs, but only at relatively low concentrations (43 ± 26 ng g^-1 dry weight). Although sampling limitations commonly associated with wild population surveys prevent a complete assessment of exposure variability, our findings suggest maternal transfer may not be a significant depuration pathway for Pb and females possibly clear Pb through other mechanisms (e.g. sequestration into claws, bone and osteoderms). Metal concentrations in eggshells and shell membranes were poorly correlated with concentrations measured in egg content and thus do not provide viable non-lethal indicators for monitoring metal exposure in Nile crocodiles. Intra-clutch variability accounted for a considerable proportion of the total variance in egg content metal concentrations, suggesting the "one egg" sampling strategy often applied in reptile studies may not be an effective biomonitoring tool for wild crocodilian populations. Although maternally derived Pb does not appear to present widespread toxicological concern at Lake St Lucia, adverse effects of Pb exposure on other reproductive functions (e.g. spermatogenesis) cannot be discounted and warrant further investigation.

Zinc as a Therapeutic Agent in Bone Regeneration

Zinc is an essential mineral that is required for normal skeletal growth and bone homeostasis. Furthermore, zinc appears to be able to promote bone regeneration. However, the cellular and molecular pathways through which zinc promotes bone growth, homeostasis, and regeneration are poorly understood. Zinc can positively affect chondrocyte and osteoblast functions, while inhibiting osteoclast activity, consistent with a beneficial role for zinc in bone homeostasis and regeneration. Based on the effects of zinc on skeletal cell populations and the role of zinc in skeletal growth, therapeutic approaches using zinc to improve bone regeneration are being developed. This review focuses on the role of zinc in bone growth, homeostasis, and regeneration while providing an overview of the existing studies that use zinc as a bone regeneration therapeutic.

Quantitation and distribution of metallic elements in sequestra of medication-related osteonecrosis of jaw (MRONJ) using inductively coupled plasma atomic emission spectroscopy and synchrotron radiation X-ray fluorescence analysis

Medication-related osteonecrosis of the jaw (MRONJ) is a serious adverse effect of antiresorptive agents like bisphosphonates. Abnormal concentrations of various trace metallic elements contained in bone minerals have been associated with MRONJ. In this study, we focused on trace metallic elements contained in the MRONJ sequestrum; their content and distribution were compared to those in osteomyelitis and non-inflammatory bones using inductively coupled plasma atomic emission spectroscopy (ICP-AES) and synchrotron radiation X-ray fluorescence analysis (SR-XRF). On ICP-AES analyses, various trace elements (Co, Cr, Cu, Fe, K, Mg, Ni, Sb, Ti, V, Pb) were significantly more in MRONJ sequestra than non-inflammatory bones. The Cu content was significantly higher in MRONJ sequestra than osteomyelitis and non-inflammatory bones. The Cu content in MRONJ sequestra was high even after decalcification. Additionally, Cu was distributed along the trabecular structures in decalcified MRONJ specimens, as observed using SR-XRF analysis. Therefore, this study was indicative of the characteristic behavior of Cu in MRONJ.