Chicken eggshell powder more effectively alleviates bone loss comparted to inorganic calcium carbonate: an animal study performed on ovariectomized rats.

This study aimed to evaluate the effects of chicken eggshell powder rich in calcium and the inorganic form of calcium carbonate on osteoporotic bone structure using an animal model of ovariectomized rats. Animals were divided into four groups: sham-operated rats (SHAM group); ovariectomized rats untreated (OVX group); OVX rats treated with eggshell powder (Biomin H® OVX + ECa group; total Ca content 1.5%); and OVX rats receiving inorganic calcium carbonate (calcium carbonate precipitated, total Ca content 1.5%; OVX + ICa group) during 8 weeks. Ovariectomy increased total body weight, plasma alkaline phosphatase activity, cortical bone thickness, periosteal bone apposition, and considerably worsened the trabecular bone microarchitecture. Calcium supplementation in both OVX + ECa and OVX + ICa groups elevated blood supply in the cortical bone when compared to OVX rats. Treatment with eggshell powder, unlike the OVX + ICa group, significantly lowered bone resorption, increased plasma calcium level, relative volume of trabecular bone, and secondary osteon population density, which together contributes to the enhanced bone strength. In addition, sizes of Haversian canals and secondary osteons in OVX + ECa group reached the values of SHAM group. Our results suggest that chicken eggshell powder more effectively ameliorates bone loss in ovariectomized rats than precipitated calcium carbonate.

Pharmacological agents and natural compounds: available treatments for osteoporosis.

Osteoporosis, a systemic skeletal disease characterized by a decrease in bone mass and deterioration of bone structure leading to an increased risk of fragility fractures, represents one of the major health problems worldwide. Currently, there are numerous pharmacological products used for the treatment of osteoporosis. Anti-resorptive drugs include bisphosphonates, hormone therapy, selective estrogen-receptor modulators, calcitonin, denosumab, calcium and vitamin D supplementation. Anabolic drugs such as teriparatide, strontium ranelate, romosozumab have recently become available based on advanced clinical trials. In recent years, combination therapy of anabolic and anti-resorptive agents is expected to be ideal anti-osteoporosis option. The adverse side effects caused by the long-term administration of pharmacological drugs have prompted researchers to study natural therapeutic compounds to find an alternative and effective way for osteoporosis treatment. Natural compounds including phytoestrogens with estrogenic effects (e.g. genistein, daidzein, icariin, dioscin, Ginkgo biloba), antioxidant and anti-inflammatory agents (e.g. acteoside, curcumin, resveratrol, Camellia sinensis), treatments that exert their effects by multiple actions (e.g. kinsenoside, berberine, Olea europaea, Prunus domestica, Allium cepa) could provide a safer alternative to primary pharmacological strategies. In this review, both pharmacological agents and natural compounds as available treatments for osteoporosis are characterized. In addition, possible mechanisms of action of all aforementioned treatments associated with bone remodelling, osteoclastogenesis, osteoblastogenesis, bone cell activity, death, and oxidative stress are presented. Nevertheless, more high-quality clinical studies with natural compounds are needed to provide greater evidence of the beneficial and safer antiosteoporotic application for the candidate.

Subacute exposure to amygdalin influences compact bone remodeling of rabbits.

Amygdalin is most commonly occurring cyanogenic glycoside. It is found in seeds of many plant species. Our study was aimed to reveal whether pure intramuscularly injected amygdalin or apricot seeds peroral exposure cause changes in bone microstructure of rabbits. Twenty clinically healthy 5 months-old male rabbits were segregated into five groups. Animals from groups A1 and A2 were intramuscularly injected with amygdalin at doses of 0.6 and 3 mg/kg b.w. daily for 28 days. The groups S1 and S2 received commercial feed for rabbits mixed with crushed bitter apricot seeds at doses of 60 and 300 mg/kg b.w. during 28 days. The control (C) group did not receive any amygdalin. Intramuscular and peroral amygdalin administration did not affect total body weight, femoral length and femoral weight of rabbits. Similarly, microcomputed tomography (3D analysis) has shown that amygdalin had insignificant effect on relative bone volume, bone mineral density, cortical bone thickness, bone surface, trabecular thickness, trabecular number, trabecular separation. However, histological (2D analysis) revealed evident changes in compact bone microstructure of amygdalin-exposed rabbits consistent with a different vascularization and changed biomechanical properties. We can conclude that subacute exposure to amygdalin (both intramuscular and peroral) at the doses used in our study influenced compact bone remodeling.

Bone microstructure of mice after prolonged taurine treatment.

Taurine, a sulphur - containing amino acid, has been termed a functional nutrient. Its synthetic form is a common ingredient in supplements and energy drinks. There is no information concerning taurine impact on bone microstructure after prolonged supplemental use. Also, differences in bone parameters of mice following taurine exposure are unknown. In this study, a detailed microstructure of compact and trabecular bone tissues of mice subchronically exposed to taurine was determined. Animals (n=12) were segregated into three groups: E1 group - mice received 20 mg/kg b.w. of taurine per day during 8 weeks; E2 group - mice were fed by taurine at a dose of 40 mg/kg b.w. for 8 weeks and a control (C) group. Decreased density of secondary osteons, increased sizes of primary osteon's vascular canals (P<0.05) were observed in taurine - treated animals. Cortical bone thickness, trabecular thickness were decreased (P<0.05) in E1 group, and relative volume of trabecular bone was lower (P<0.05) in E2 group as compared to C group. According to our results, prolonged taurine exposure at the doses used in this study can negatively affect both compact and trabecular bone tissues microstructure.

Subacute exposure to alcohol in relation to bone microstructure of mice.

Our study aimed to investigate subacute exposure to alcohol in relation to bone microstructure of mice. Animals from experimental (E) group drank a solution composed of 15 % ethanol and water for 14 days (one remodeling cycle), while those from control (C) group drank only water. In the compact bone of E group, decreased bone formation and increased porosity were observed which corresponds with lower levels of serum alkaline phosphatase and glutathione. Alcohol significantly increased sizes of primary osteon's vascular canals and decreased those of secondary osteons, Haversian canals. Relative bone volume, bone mineral density (BMD), relative bone volume without marrow cavity were also lower in E group. On the contrary, trabecular bone microstructure did not differ significantly between E and C groups. Liver function test showed higher levels of alanine aminotransferase, aspartate aminotransferase in alcohol-fed mice. Serum calcium, phosphate were significantly lower in E group. According to our study, only changes in compact bone microstructure of mice following one remodeling cycle were observed due to both direct and indirect effects of alcohol.

Acrylamide-induced changes in femoral bone microstructure of mice.

Acrylamide (AA) is one of the most common toxins in foods. Its effect on bone microstructure has not been investigated. The aim of our study was to analyze the impact of acute exposure to AA on femoral bone microstructure in mice. Adult animals were treated perorally with 2 doses of AA (E1 group, 1 mg/kg b.w.) in a 24-h period and with 3 doses of AA (E2 group, 1 mg/kg b.w.) in a 48-h period. Mice exposed to AA had smaller sizes of primary osteon's vascular canals. Secondary osteons were significantly smaller in mice from E2 group; however their increased number (from 38 % to 77 %) was identified in both E1 and E2 groups. In these groups, a higher number of resorption lacunae (from 100 % to 122 %) was also found. The values for bone volume, trabecular number were increased and that for trabecular separation was decreased in mice administered AA. Significantly higher value of bone surface was observed in mice from E1 group whereas trabecular thickness was increased in E2 group. The effect of AA on microstructure of compact and trabecular bone tissues is different. In our study, one dose of AA was used and acute effects of AA were investigated. Therefore, further studies are needed to study mechanisms by which AA acts on bone.

Acrylamide: a common food toxin related to physiological functions and health.

Acrylamide (AA) is a highly reactive organic compound capable of polymerization to form polyacrylamide, which is commonly used throughout a variety of industries. Given its toxic effect on humans and animals, the last 20 years have seen an increased interest in research devoted to the AA. One of the main sources of AA is food. AA appears in heated food following the reaction between amino acids and reduced sugars. Large concentrations of AA can be found in popular staples such as coffee, bread or potato products. An average daily consumption of AA is between 0.3-2.0 microg/kg b.w. Inhalation of acrylamide is related with occupational exposure. AA delivered with food is metabolized in the liver by cytochrome P450. AA biotransformation and elimination result in formation of toxic glycidamide (GA). Both, AA and GA can be involved in the coupling reaction with the reduced glutathione (GSH) forming glutathione conjugates which are excreted with urine. Biotransformation of AA leads to the disturbance in the redox balance. Numerous research proved that AA and GA have significant influence on physiological functions including signal propagation in peripheral nerves, enzymatic and hormonal regulation, functions of muscles, reproduction etc. In addition AA and GA show neurotoxic, genotoxic and cancerogenic properties. In 1994, International Agency for Research on Cancer (IARC) classified acrylamide as a potentially carcinogenic substance to human.

Concentrations of selected heavy metals in bones and femoral bone structure of bank (Myodes glareolus) and common (Microtus arvalis) voles from different polluted biotopes in Slovakia.

Concentrations of selected heavy metals in the femora and femoral bone structure of bank (Myodes glareolus) and common (Microtus arvalis) voles from different polluted biotopes in Slovakia (Kolínany and Nováky sites) were investigated. Length, weight, and histological structure of vole bones were also analyzed. We observed higher concentrations of lead (Pb), iron (Fe), copper (Cu), and zinc (Zn) in the bones of both species from the Kolínany site. Significant differences were observed in the concentration of Fe in bank and common voles (p<0.05) and in the concentration of Zn (p<0.05) in common voles. The animals from Nováky had higher concentrations of cadmium (Cd) and nickel (Ni) in their bones; however, the differences were not significant. The measured values for bone length and weight were higher in both species from Nováky (p<0.05). We did not identify differences in qualitative histological characteristics of the femora between the voles (M. glareolus and M. arvalis separately) between the two biotopes. In addition, no statistically significant differences for any the measured variables of primary osteons' vascular canals were observed. Correlation analysis in M. glareolus showed a strong positive relation between Cd and Ni (r=0.52), Pb and bone weight (r=0.53), Fe and bone weight (r=0.52), and Fe and perimeter size of primary osteons' vascular canals (r=0.55). In common voles, a strong positive relation was found between Fe and Cu (r=0.60) and between Fe and perimeter size of vascular canals of primary osteons (r=0.55). Our results indicate that accumulation of some heavy metals is slightly increased in the femora of both species at Kolínany.

Femoral bone microstructure in 1-month-old non-transgenic versus transgenic rabbits with the WAP-hFVIII gene construct.

Differences in microscopic structure of the femur between 1-month-old transgenic rabbits carrying the hFVIII gene and non-transgenic rabbits were investigated. Bone microstructure was evaluated from the point of view of qualitative and quantitative histological characteristics. We identified fibrolamellar bone tissue only in the transgenic animals. Measured values for area, perimeter of the Haversian canals and minimum diameter of the primary osteons' vascular canals were higher in 1-month-old transgenic individuals (P < 0.05; P < 0.001). We also observed lower concentrations of Ca, P, K, solids, and total mineral content in femora of transgenic rabbits. A statistically significant difference was observed for the concentration of Ca (P < 0.05). Our results indicate evident changes in both qualitative and quantitative histological characteristics of the femur, which result especially in better blood supply and slightly reduced mineralization process in 1-month-old transgenic rabbits.

Comparative study of compact bone tissue microstructure between non-transgenic and transgenic rabbits with WAP-hFVIII gene construct.

The aim of this study was to investigate differences in compact bone tissue microstructure between New Zealand White transgenic rabbits with human blood clotting factor VIII gene and the non-transgenic ones. The transgene was under the transcriptional control of the whey acidic protein (WAP) promoter. Altogether, 42 femora were analysed. Specimens were prepared using standard histological equipment, producing thin sections approximately 80-100 microm. Areas, perimeters, minimum and maximum diameters of vascular canals of primary osteons, Haversian canals and secondary osteons were measured. Our results indicate the basic structural pattern of the bone tissue was primary vascular longitudinal in both groups of rabbits. However, a fibrolamellar bone tissue was identified only in the transgenic rabbits. The measured variables of the vascular canals of the primary osteons, the Haversian canals and the secondary osteons were higher in transgenic rabbits in comparison with non-transgenic ones in most cases and the differences were often statistically significant (P < 0.01; P < 0.001). More significant differences were noticed in males (transgenic versus non-transgenic). However, it is not easy to find the real cause of the changes. Despite the fact that no hFVIII mRNA expression was found in the analysed bone of transgenic rabbits, we presume that the observed differences could be associated with transgenesis. In this article, we discuss possible associations between transgene integration as well as aneuploidy and/or observed microstructural changes in compact bone tissue.

Differences in femoral compact bone tissue microscopic structure between adult cows (Bos taurus) and pigs (Sus scrofa domestica).

The purpose of this investigation was to study in detail compact bone tissue microscopic structure of adult cows and pigs with an emphasis to find an adequate key for the species identification. Altogether 18 femurs were analysed. Each of the bones was sectioned at the smallest breadth of their diaphysis. Specimens were prepared using standard histological equipment, producing thin sections approximately 80-100 mum thick. The qualitative differences between investigated species were examined in anterior, posterior, medial and lateral views of thin sections. The quantitative ones were counted using the specific computer software Scion Image. We measured the area, perimeter, minimal and maximal diameter of the Haversian canals, the Haversian systems and the vascular canals of primary osteons. After that a discriminant function analysis was used for the species identification. According to our results the basic structural pattern of femur diaphysis was primary vascular plexiform in both species. However, non-vascular bone tissue was identified in cows and resorption lacunae were found between the secondary osteons in pigs. The measured variables of the Haversian canals, the Haversian systems and the primary osteon's vascular canals were higher in most cases in cows. Classification functions for investigated species give a correct classification of 64.69% of cases. This percentage value can be increased by integrating conclusions from the qualitative analysis.

Changes of femoral bone tissue microstructure in transgenic rabbits.

Bone tissue microstructure of femur was investigated in transgenic New Zealand White rabbits with human factor VIII gene. Altogether 42 bones (24 from transgenic rabbits and 18 from non-transgenic ones) were analysed. Specimens were prepared using standard histological equipment, producing thin sections of approximately 80-100 microm. For histomorphometrical analysis areas, perimeters, minimum and maximum diameters of osteons' vascular canals and of osteons were measured. We found out that the basic structural pattern of femoral bone tissue was primary vascular longitudinal in both groups of rabbits. However, a new type of the bone tissue--fibrolamellar--was identified only in the transgenic rabbits. The measured variables of the osteons' vascular canals were higher in transgenic individuals in comparison with the nontransgenic ones (except for maximal diameter) and the differences were statistically significant (P < 0.05; P < 0.01). We suppose that the observed differences could be associated with transgenesis. In an effort to explain these differences we compared the cytogenetic profile of bone marrow cells between transgenic and non-transgenic rabbits. A significantly higher rate of aneuploidy was observed in c-metaphase spreads of transgenic individuals as compared to non-transgenic ones (P < 0.001). Despite the fact that no hFVIII mRNA expression was found in the femur of transgenic rabbits, we discussed an association of transgene integration into the genome and microstructural changes in the bone. In any case, the results indicate that transgenesis can also produce changes in other tissues than in the target ones.