Bone turnover markers in sheep and goat: A review of the scientific literature

Clodronate disodium does not produce measurable effects on bone metabolism in an exercising, juvenile, large animal model

Bisphosphonates are commonly used to treat and prevent bone loss, but their effects in active, juvenile populations are unknown. This study examined the effects of intramuscular clodronate disodium (CLO) on bone turnover, serum bone biomarkers (SBB), bone mineral density (BMD), bone microstructure, biomechanical testing (BT), and cartilage glycosaminoglycan content (GAG) over 165 days. Forty juvenile sheep (253 ± 6 days of age) were divided into four groups: Control (saline), T0 (0.6 mg/kg CLO on day 0), T84 (0.6 mg/kg CLO on day 84), and T0+84 (0.6 mg/kg CLO on days 0 and 84). Sheep were exercised 4 days/week and underwent physical and lameness examinations every 14 days. Blood samples were collected for SBB every 28 days. Microstructure and BMD were calculated from tuber coxae (TC) biopsies (days 84 and 165) and bone healing was assessed by examining the prior biopsy site. BT and GAG were evaluated postmortem. Data, except lameness data, were analyzed using a mixed-effects model; lameness data were analyzed as ordinal data using a cumulative logistic model. CLO did not have any measurable effects on the skeleton of sheep. SBB showed changes over time (p ≤ 0.03), with increases in bone formation and decreases in some bone resorption markers. TC biopsies showed increasing bone volume fraction, trabecular spacing and thickness, and reduced trabecular number on day 165 versus day 84 (p ≤ 0.04). These changes may be attributed to exercise or growth. The absence of a treatment effect may be explained by the lower CLO dose used in large animals compared to humans. Further research is needed to examine whether low doses of bisphosphonates may be used in active juvenile populations for analgesia without evidence of bone changes.

Osseointegration of photodynamic active biomaterials for bone regeneration in an animal bone model over a period of 12 months

OBJECTIVES

Previous efforts led to the development of two different polymeric biomaterials for periodontal regeneration with antibacterial photodynamic surface activity. The present study aimed to investigate osseointegration and bone formation of both materials in an ovine model.

METHODS

Both biomaterials: 1) urethane dimethacrylate-based Biomaterial 1 (BioM1) and 2) tri-armed oligoester-urethane methacrylate-based Biomaterial 2 (BioM2) are enriched with beta-tri-calcium phosphate and the photosensitizer meso-tetra(hydroxyphenyl)chlorin (mTHPC). These materials were implanted in non-critical size bone defects in the sheep femur (n = 16) and tibia (n = 8). Empty defects served as controls (n = 16). Polyfluorochrome sequential bone labeling was carried out at baseline and after 3, 6, and 12 months. Animals were sacrificed after 12 months. Bone specimens (n = 40) were fixed and subjected to microtomographic analysis (µCT) for the evaluation of the bone-volume-fraction (BV/TV), trabecular number and trabecular thickness. Subsequently, histological sections were arranged and polyfluorochrome sequential bone labeling was analyzed by confocal laser scanning microscopy (cLSM).

RESULTS

cLSM analysis revealed that highest remodeling and bone formation activity occurred during the second half of the study period (6-12 months). Bone formation in the tibia was significantly lower for the control (2.71 ± 1.26%) as compared to BioM1 (6.01 ± 2.99%) and BioM2 (6.45 ± 2.12%); (p = 0.006, p = 0004). Micro-computed tomography revealed a BV/TV volume fraction of 44.72 ± 9.01% in femur defects filled with BioM1 which was significantly higher compared to the control (32.27 ± 7.02%; p = 0.01). Bone architecture (trabecular number, trabecular thickness) did not significantly differ from the self-healed defects.

SIGNIFICANCE

Both biomaterials, especially BioM1 showed good osseointegration and bone formation characteristics and can be recommended for further examination in periodontal regeneration studies.

Why Animal Experiments Are Still Indispensable in Bone Research: A Statement by the European Calcified Tissue Society

Major achievements in bone research have always relied on animal models and in vitro systems derived from patient and animal material. However, the use of animals in research has drawn intense ethical debate and the complete abolition of animal experimentation is demanded by fractions of the population. This phenomenon is enhanced by the reproducibility crisis in science and the advance of in vitro and in silico techniques. 3D culture, organ-on-a-chip, and computer models have improved enormously over the last few years. Nevertheless, the overall complexity of bone tissue cross-talk and the systemic and local regulation of bone physiology can often only be addressed in entire vertebrates. Powerful genetic methods such as conditional mutagenesis, lineage tracing, and modeling of the diseases enhanced the understanding of the entire skeletal system. In this review endorsed by the European Calcified Tissue Society (ECTS), a working group of investigators from Europe and the US provides an overview of the strengths and limitations of experimental animal models, including rodents, fish, and large animals, as well the potential and shortcomings of in vitro and in silico technologies in skeletal research. We propose that the proper combination of the right animal model for a specific hypothesis and state-of-the-art in vitro and/or in silico technology is essential to solving remaining important questions in bone research. This is crucial for executing most efficiently the 3R principles to reduce, refine, and replace animal experimentation, for enhancing our knowledge of skeletal biology, and for the treatment of bone diseases that affect a large part of society. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

The influence of sex and age on bone turnover markers in the adult to geriatric Kangal shepherd dogs

OBJECTIVES

The objective of this research was to learn more about bone metabolism in intact female and male Kangal shepherd dogs during the aging process following skeletal maturity. It also evaluated the potential application of biochemical bone indicators in veterinary clinical practice.

METHODS

Bone markers were determined as bone alkaline phosphatase (BALP), osteocalcin (OC), C-terminal telopeptide of type I collagen (CTX), and cross-linked C-telopeptide of type I collagen (ICTP) in this study. Kangal shepherd dogs of different age (adult, senior, and geriatric) and sex (male and female) groups were split into six groups of equal numbers (n = 8/group).

RESULTS

In this study, the effect of age was observed on serum BALP, OC, CTX, and ICTP concentrations. Specifically, BALP was highest in geriatric female Kangal shepherd dogs, while serum OC, CTX, and ICTP concentrations were highest in geriatric male Kangal shepherd dogs. However, no effects of sex and age-sex interactions were identified. Moreover, the effects of age, sex, and age-sex interactions had no significant effect on serum creatinine, CK, LDH, Mg, and P concentrations or ALT activities. However, only sex was found to affect serum AST activities and gradually decreased with age in females. The effect of age and age-sex interactions on serum Ca concentrations was significant (the lowest serum Ca concentrations were in geriatric females), but the effect of sex was not.

CONCLUSIONS

These results show the effect of age and sex on bone turnover in Kangal shepherd dogs and provide information about bone biomarkers.

The Contribution of the Sheep and the Goat Model to the Study of Ovarian Ageing

Ovarian ageing stands as the major contributor towards fertility loss. As such, there is an urge for studies addressing the mechanisms that promote ovarian ageing and new strategies aiming to delay it. Recently, the presence of a unique population of multinucleated giant cells has been identified in the ovaries of reproductively aged mice. These cells have been considered hallmarks of ovarian ageing. However, up to date multinucleated giant cells have only been described in the ovaries of the mice. Therefore, the aim of the present work was to evaluate and characterize the presence of such hallmarks of ovarian ageing in the sheep and the goat. In this study, ovaries from juvenile (6 months) and mature animals (18-24 months) were used. The hematoxylin and eosin technique was performed to describe the ovarian morphology and evaluate the ovarian follicle reserve pool. Sudan black B staining and the detection of autofluorescence emission were used to identify and characterize the presence of multinucleated giant cells. Statistical analyses were performed with GraphPad Prism 9.0.0. A decrease in the follicle reserve pool and the presence of multinucleated giant cells, with lipofuscin accumulation and the emission of autofluorescence, were observed in the ovaries of the mature animals of both species. Our results support the interest in the use of the ovine and the caprine model, that share physiological and pathophysiological characteristics with humans, in future studies addressing ovarian ageing.

Experimental Exposure to Bisphenol A Has Minimal Effects on Bone Tissue in Growing Rams—A Preliminary Study

Simple Summary

Bisphenol A (BPA) is a well-known synthetic compound that belongs to the group of chemicals that disrupt the endocrine system in humans and animals. Although bones represent a potential target for these compounds, studies investigating BPA-related effects in bones in large farm animals are limited. We exposed young rams aged 9–12 months to BPA through feed for 64 days and investigated the effects of BPA on bone length, mass, microscopic structure, mineral content, strength, and serum bone parameters. We discovered that BPA had no significant effects on most of the parameters studied. Only manganese was decreased, and copper increased in the femurs of the BPA-exposed rams. These results suggest that a 2-month, low-dose exposure to BPA in growing rams did not affect the macro- and microstructure, metabolism, and biomechanical behavior of femur bones; however, it did affect the composition of microelements in bone, which could affect the bone in the long term.

Abstract

Bisphenol A (BPA) is a well-known synthetic compound that belongs to the group of endocrine-disrupting chemicals. Although bone tissue is a target for these compounds, studies on BPA-related effects on bone morphology in farm animals are limited. In this preliminary study, we investigated the effects of short-term dietary BPA exposure on femoral morphology, metabolism, mineral content, and biomechanical behavior in rams aged 9–12 months. Fourteen rams of the Istrian Pramenka breed were randomly divided into a BPA group and a control group (seven rams/group) and exposed to 25 µg BPA/kg bw for 64 days in feed. Blood was collected for determination of bone turnover markers (procollagen N-terminal propeptide, C-terminal telopeptide), and femurs were assessed via computed tomography, histomorphometry, three-point bending test, and mineral analysis. BPA had no significant effects on most of the parameters studied. Only mineral analysis showed decreased manganese (50%; p ≤ 0.05) and increased copper content (25%; p ≤ 0.05) in the femurs of BPA-exposed rams. These results suggest that a 2-month, low-dose exposure to BPA in growing rams did not affect the histomorphology, metabolism, and biomechanical behavior of femurs; however, it affected the composition of microelements, which could affect the histometric and biophysical properties of bone in the long term.

A review on bioceramics scaffolds for bone defect in different types of animal models: HA and β -TCP

Increased life expectancy has led to an increase in the use of bone substitutes in numerous nations, with over two million bone-grafting surgeries performed worldwide each year. A bone defect can be caused by trauma, infections, and tissue resections which can self-heal due to the osteoconductive nature of the native extracellular matrix components. However, natural self-healing is time-consuming, and new bone regeneration is slow, especially for large bone defects. It also remains a clinical challenge for surgeons to have a suitable bone substitute. To date, there are numerous potential treatments for bone grafting, including gold-standard autografts, allograft implantation, xenografts, or bone graft substitutes. Tricalcium phosphate (TCP) and hydroxyapatite (HA) are the most extensively used and studied bone substitutes due to their similar chemical composition to bone. The scaffolds should be testedin vivoandin vitrousing suitable animal models to ensure that the biomaterials work effectively as implants. Hence, this article aims to familiarize readers with the most frequently used animal models for biomaterials testing and highlight the available literature for in vivo studies using small and large animal models. This review summarizes the bio ceramic materials, particularly HA and β-TCP scaffolds, for bone defects in small and large animal models. Besides, the design considerations for the pre-clinical animal model selection for bone defect implants are emphasized and presented.

Evaluation of in vitro corrosion resistance and in vivo osseointegration properties of a FeMnSiCa alloy as potential degradable implant biomaterial

In vitro electrochemical characterization and in vivo implantation in an animal model were employed to evaluate the degradation behaviour and the biological activity of FeMnSi and FeMnSiCa alloys obtained using UltraCast (Ar atmosphere) melting. Electrochemical characterization was based on open circuit potential measurement, electrochemical impedance spectroscopy and potentiodynamic polarization techniques while the alloys were immersed in Ringer's solution at 37 °C for 7 days. Higher corrosion rates were measured for the Ca-containing material, resulting from inefficient passivation of the metal surface by oxy-hydroxide products. In vivo osseointegration was investigated on a tibia implant model in rabbits by referring to a standard control (AISI 316 L) stainless steel using standard biochemical, histological and radiological methods of investigation. Changes in the biochemical parameters were related to the main stages of the bone defect repair, whereas implantation of the alloys in rabbit's tibia provided the necessary mechanical support to the injured bone area and facilitated the growth of the newly connective tissue, as well as osteoid formation and mineralization, as revealed by either histological sections or computed tomography reconstructed images and validated by the bone morphometric indices. The present study highlighted that the FeMnSiCa alloy promotes better osteoinduction and osseconduction processes when compared to the base FeMnSi alloy or with AISI 316 L, and in vivo degradation rates correlate well with corrosion resistance measurements in Ringer's solution.

Hyaluronic Acid Stimulates Osseointegration of β-TCP in Young and Old Ewes

Cross-linked hyaluronic acid (HyAR) increases the local concentration of growth factors. We compared β-TCP osseointegration in old and young ewes with/without HyAR addition. A blind tunnel was drilled on the medial femoral condyle of each knee in nine young and nine old ewes and was filled with β-TCP, β-TCP + HyAR or left unfilled. Double labeling with calcein allowed histodynamic analysis. Ewes were sacrificed at 84 days and the knees were harvested. MicroCT provided histomorphometric parameters: trabecular bone volume, residual volume of biomaterial. Histodynamic parameters were: mineralization rate, mineralized surfaces, bone formation rate. A non-parametric ANOVA and post hoc test analyzed differences between subgroups. Osseointegration of β-TCP was similar in the aged/young grafted groups. Trabecular bone volume was significantly increased versus ungrafted animals (p < 0.001). There were no significant difference for bone volume, residual volume of biomaterial and histodynamic parameters when a single parameter was considered but additional effects of β-TCP and HyAR were evidenced by 3D analysis. Addition of HyAR to ß-TCP does not significantly increase bone volume but tends to increase histodynamic parameters. However, considering the reduction of osteoblastic activity in aged animals, β-TCP, and HyAR boosts osteoblastic activity. HyAR leads to an equivalent response between young and old animals.

Curcumin Promotes Femoral Fracture Healing in a Rat Model by Activation of Autophagy

BACKGROUND The aim of this study was to use a rat model of femoral fracture healing to study the effects of curcumin on cell autophagy, compared with treatment with 3-methyladenine (3-MA), an inhibitor of autophagy. MATERIAL AND METHODS Thirty-six Sprague-Dawley rats with right mid-femoral fracture were divided into three groups: the curcumin-treated group (N=12) (gavage with curcumin 400 mg/kg/day); the curcumin + 3-MA-treated group (gavage with curcumin 400 mg/kg/day + 3-MA 30 mg/kg/day); and the control group (N=12) (gavage normal saline). Each group underwent femoral bone imaging using anteroposterior X-ray and micro-computed tomography (CT) at two weeks and six weeks following bone fracture. All rats were euthanized at the end of the study. Histology of the bone was performed to compare bone healing. Immunofluorescence and immunohistochemical tissue staining and Western blots were performed, to compare the expression of autophagy-related proteins, Beclin-1 and LC3-II. RESULTS Autophagy of rat femoral bone tissue was activated following fracture, increasing with time, reaching a peak at 24 hours. Imaging and histology showed that curcumin promoted the fracture healing in rats, which was reduced by treatment with 3-MA. Immunohistochemistry, immunofluorescence, and Western blot showed that curcumin treatment increased the expression of Beclin-1 and LC3-II, which were reduced by treatment with the autophagy inhibitor, 3-MA. CONCLUSIONS The findings of this study, in a rat model of femoral bone fracture healing, showed that curcumin promoted bone healing and autophagy, which were reduced by treatment with 3-MA, a known inhibitor of autophagy.

New candidate markers of phosphorus status in beef breeder cows

Determining the phosphorus (P) status of cattle grazing P-deficient rangelands in northern Australia is important for improving animal production in these areas. Plasma inorganic P concentration is currently the best diagnostic marker of dietary P deficiency in growing cattle but is not suitable for assessing the P status of breeder cows, which often mobilise substantial bone and soft tissue reserves in late pregnancy and lactation. Markers of bone turnover offer potential as markers of P status in cattle, as they reflect bone mobilisation or bone formation. Recent experiments investigating the physiology of beef breeder cows during diet P deficiency have indicated that the ratio of plasma total calcium concentration to plasma inorganic P concentration might be suitable as a simple index of P deficiency. However, a more specific measure of increased bone mobilisation in P-deficient breeders is plasma concentration of C-terminal telopeptide of Type 1 collagen. Also, plasma concentration of bone alkaline phosphatase is a marker of defective bone mineralisation in dietary P deficiency. These candidate markers warrant further investigation to determine their predictive value for P deficiency in cattle.