Distribution of structural and trace elements in human temporal bone

The Effect of Sensory Innervation on the Inorganic Component of Bones and Teeth; Experimental Denervation - Review

The effect of the nervous system on bone remodelling has been described by many studies. Sensory and autonomic nerves are present in the bone. Immunohistochemical analysis of the bone have indicated the presence of neuropeptides and neurotransmitters that act on bone cells through receptors. Besides carrying sensory information, sensory neurons produce various neuropeptides playing an important role in maintaining bone and tooth pulp homeostasis, and dentin formation. Bone tissue and teeth contain organic and inorganic components. Bone cells enable bone mineralization and ensure its formation and resorption. Studies focused on the effects of the nervous system on the bone are proceeded using various ways. Sensory denervation itself can be achieved using capsaicin causing chemical lesion to the nerve. Surgical ways of causing only sensory lesion to nerves are substantially limited because many peripheral nerves are mixed and contain a motor component as well. From this point of view, the experimental model with transection of inferior alveolar nerve is appropriate. This nerve provides sensory innervation of the bone and teeth of the mandible. The purpose of our paper is to provide an overview of the effects exerted by the nervous system on the inorganic component of the bone and teeth, and also to present an overview of the used experimental models. As we assume, the transection of inferior alveolar nerve could be reflected in changed contents and distribution of chemical elements in the bone and teeth of rat mandible. This issue has not been studied so far.

The influence of the place of residence, smoking and alcohol consumption on bone mineral content in the facial skeleton

BACKGROUND

Environmental factors exert their influence on the living organism throughout ontogeny. More and more often, researchers find correlations between specific environmental factors and the so-called diseases of affluence. Deficits and excess of essential elements also leave their mark on the skeleton.

AIM

To investigate the influence of alcohol consumption, tobacco smoking and place of residence, according to sex and calendar age, on the concentrations of micro-, macro- and toxic elements in human facial bones.

MATERIAL & METHODS

Patients undergoing surgical treatment were examined for the mineral content in the collected bone material. The bone contents of the following elements were determined: Ca, K, Mg, Na, P, Fe, Zn, Mo, Ba, Mn, Li, Be, Co, B, Sr, Cr, Pb, Cd, Ni, and Al, depending on the type of facial bone, sex, calendar age, alcohol consumption, tobacco smoking and place of residence.

RESULTS

Sex and alcohol consumption showed the highest degree of correlation with the content of the minerals included in the study. Alcohol drinking was found to exert the strongest influence on women's bodies, the highest number of statistically significant correlations was demonstrated between the content of minerals in the examined bones and alcohol drinking in women. Other factors included in the analysis had a different impact on men and women, the concentrations of elements included in the study differed depending on age, tobacco smoking and place of residence.

CONCLUSIONS

The observed differences in the element mineral composition of the human facial skeleton may be explained by developmental specifics and functional adaptation. However, general biological characteristics (sex, age), environmental factors (place of residence), as well as smoking and alcohol use may exert significant influence on the concentrations of micro-, macro- and toxic elements in particular regions of the human skeleton. The impact of environmental factors is a very complex phenomenon, which may be stronger or more subtle, leaving its mark on the bone structure. The environmental factors included in the analysis had a different influence on men than women.

Strontium distribution and interactions with bone mineral in monkey iliac bone after strontium salt (S 12911) administration

The analysis of the interaction of strontium (Sr) with bone mineral is of interest because a new agent containing Sr (S 12911) has shown positive effects on bone mass in various animal models of osteoporosis and is currently being developed for preventive and curative treatment of postmenopausal osteoporosis. Iliac bone samples were obtained from 20 male monkeys: 4 untreated control animals, 12 animals sacrificed at the end of a 13-week treatment with high dose levels of S 12911 (750, 275, or 100 mg/kg/day orally), and 4 animals sacrificed 6 weeks after the end of a 13-week treatment with S 12911 (750 or 100 mg/kg/day orally). The distribution of Sr was determined and quantified by X-ray microanalysis. Changes at the crystal level were evaluated by X-ray diffraction and Raman microspectrometry. In the control animals, traces of Sr were found to be homogeneously distributed throughout the bone tissue. In the treated monkeys, Sr could only be detected in calcified matrix. In monkeys sacrificed at the end of the treatment, Sr was found to be dose-dependently incorporated into the mineral substance of the compact and cancellous bone. Sr was heterogeneously distributed with three to four times more Sr in new than in old compact bone, and approximately two and a half times more Sr in new than in old cancellous bone. The bone Sr content dramatically decreased in the animals sacrificed 6 weeks after the end of the treatment. Diffraction showed no significant changes in the characteristics of the crystal lattice. Sr appeared to be easily exchangeable from bone mineral and was slightly linked to mature crystals through ionic substitutions. Even at the highest dose level tested, less than 1 calcium ion out of 10 was substituted by 1 Sr ion in each crystal. In conclusion, taken up by bone, Sr was heterogeneously distributed with a higher concentration in new than in old bone but induced no major modifications of the bone mineral (crystallinity, crystal structure) at the crystal level. As a result, a treatment with S 12911 Sr salt should not induce any alteration of bone mineral.