Diurnal variation of plasma bone markers in Japanese black calves

Circadian rhythm of markers of bone turnover in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) have a high risk of bone fractures. A circadian rhythmicity in turnover and mineralization of bone appears to be of importance for bone health. In CKD disturbances in the circadian rhythm of various functions has been demonstrated and indeed the circadian rhythm in the mineral metabolism is disturbed. The aim of the present study was to compare the circadian rhythm of bone turnover markers in ten patients with CKD to ten healthy controls. Bone turnover markers (C-terminal telopeptide of type I collagen, tartrate-resistant acid phosphatase 5b, N-terminal propeptide of type I procollagen, bone alkaline phosphatase and osteocalcin) were measured every third hour for 24 h. All bone turnover markers displayed a significant circadian rhythm in both groups and there were no significant differences in the rhythmicity between the two groups (no group*time interaction). As expected, due to the reduced renal clearance, the overall level of C-terminal telopeptide of type I collagen and osteocalcin was higher in CKD compared to the healthy controls. The present study suggests that disturbances in the circadian rhythm of bone turnover do not explain the metabolic bone disease and increased risk of fractures in CKD.

Prepartum measurement of serum biomarkers reflecting osteoclastic and osteoblastic bone metabolism for predicting the risk of milk fever in dairy cows

We investigated whether prepartum levels of serum bone biomarkers are related to the degree of parturient hypocalcaemia and risk of milk fever (MF) in dairy cows with advancing parity. A total of 58 late-pregnant cattle were assigned to four groups: nulliparous, primiparous, multiparous in the 2nd lactation and multiparous in the 3rd-5th lactation. The multiparous cows were further assigned to MF and non-MF groups according to the onset of MF. Serum samples were obtained from the cows during the 3 weeks prepartum to 5 d postpartum period for the measurement of serum calcium (Ca) and three bone biomarkers: tartrate-resistant acid phosphatase isoform 5b (TRAP5b), osteoprotegerin (OPG) and bone isoenzyme of alkaline phosphatase (ALP3). The ratios of OPG to TRAP5b (O/T ratio) and ALP3 to TRAP5b (A/T ratio) were calculated. The data from all cattle showed that the severity of hypocalcaemia at parturition increased with advancing parity/age. The MF cows had elevated serum TRAP5b activity and a decreased O/T ratio after parturition, suggesting an increased number of osteoclasts due to osteoclastogenesis, in response to severe hypocalcaemia. The MF cows showed lower serum ALP3 activity during the 3 weeks prepartum than the non-MF cows, therefore, prepartum osteoblast function was likely weak in the MF cows. During the 2-3 weeks prepartum, serum ALP3 activity and the A/T ratio had moderate associations with the serum Ca concentration at day 0 (day of calving) in the multiparous cows, and receiver operating characteristic curve analysis revealed that ALP3 activity had excellent ability to predict MF. In conclusion, prepartum serum ALP3 activity is a promising biomarker to predict MF in multiparous cows.

Blood markers of osteoclastic differentiation in periparturient dairy cows at different parities, with and without milk fever

Osteoprotegerin (OPG) inhibits osteoclast (OC) differentiation. TRAP5b (tartrate-resistant acid phosphatase 5b) secreted by OCs reflects the numbers of mature OCs. This study assessed these OC-related markers around parturition in cows of different parities and in cows with milk fever (MF). The blood OPG and TRAP5b concentrations, as well as the ratio of OPG to TRAP5b (O/T), were measured beginning 3 weeks before (-21 d) and over a few days after calving in 49 Holstein Friesian cows at first (n = 8), second (n = 17), third (n = 12), and fourth or greater (n = 12) parities. The ratio of O/T at -21 d to O/T at calving (PreCOT) was also calculated. In the third and greater parities, seven cows developed MF (non-MF, n = 17). Regardless of the development of MF, the serum OPG started to decline in the last week of gestation only in the cows entering the second lactation, while the blood TRAP5b increased at calving in all cows. O/T decreased toward parturition only in multiparous cows. The decrease in O/T at caving was less pronounced in MF cows. PreCOT was negatively correlated with lactation number only in multiparous cows (n = 41, ρ = -0.50, P < .01). This study implied that OC differentiation toward calving was tapered in cows with advanced parities, and these indexes predict the risk of MF.

Calves, as a model for juvenile horses, need only one sprint per week to experience increased bone strength

Previous research has determined that maintaining young animals in stalls is detrimental to their bone health, while the addition of 50 to 82-m sprints 5 d/week aids in counteracting the reduction of bone strength from confinement. The current research aims to determine if 1 or 3 d/week of sprinting affords the same benefits to bone as 5 d/week of sprinting compared to animals confined with no sprinting. Twenty-four Holstein bull calves were obtained from the Michigan State University Dairy Cattle Teaching and Research Center. At 9 wk of age, calves were randomly assigned to treatments of 1, 3, or 5 d/week of sprint exercise, or to the confined control group sprinted 0 d/week. Each treatment had 6 calves. Individual sprinting bouts included a single sprint down a 71-m concrete aisle. For the duration of the 6-wk study, calves were housed at the MSU Beef Cattle Teaching and Research Center in stalls which afforded calves room to stand, lay down, and turn around. Serum was collected weekly via jugular venipuncture to obtain concentrations of osteocalcin (OC) and C-telopeptide crosslaps of type I collagen (CTX-1)—markers of bone formation and degradation, respectively. Sprints were videotaped weekly to determine stride frequency and sprint velocity. On day 42, calves were humanely euthanized at the Michigan State University Meat Lab and both front limbs were immediately harvested. Computed tomography scans and mechanical testing were performed on the left fused third and fourth metacarpal bones. Serum OC concentration was greatest for calves sprinted 5 d/week (P < 0.001). Calves sprinted 5 d/week had both greater stride frequency (P < 0.05) and lower sprint velocity (P < 0.05). All exercise treatments experienced greater dorsal cortical widths compared to control animals (P < 0.01). Through mechanical testing, fracture forces of all sprinting treatments were determined to be greater than the control treatment (P < 0.02). Results from this study support that sprinting 1, 3, or 5 d/week during growth can increase bone health and cause favorable alterations in bone markers. While all exercise treatments had over a 20% increase to fracture force, calves sprinted 1 d/week sprinted only 426 m over the 6-wk study and still experienced over a 20% increase in bone strength compared to confined calves. This study demonstrates the remarkably few strides at speed needed to enhance bone strength and emphasizes the danger to skeletal strength if sprinting opportunities are not afforded.

Molecular biology of periodontal ligament fibroblasts and orthodontic tooth movement : Evidence and possible role of the circadian rhythm

PURPOSE

The circadian clock plays an important role in many physiological states and pathologies. The significance of its core genes in bone formation and tooth development has already been demonstrated. However, regulation of these genes and their influence on periodontal and bone remodeling in periodontal ligament (PDL) fibroblasts remains to be elucidated. Our hypothesis was that the circadian clock influences markers for periodontal and bone remodeling and therefore orthodontic tooth movement itself.

MATERIALS AND METHODS

Human PDL fibroblasts were cultured and synchronized in circadian rhythms with the help of a dexamethasone shock. Cells were harvested at 4 h intervals. Reverse transcription and quantitative RT PCR (real time polymerase chain reaction) were performed to assess the mRNA levels of the clock genes ARNTL, CLOCK1, PER1, and PER2. Subsequently, mRNA expression of important marker genes for periodontal and bone remodeling, OPG, RANKL, OCN, OPN, RUNX2, COL1A1, IL1β, KI67, and POSTN, were examined at time points of ARNTL amplitude expression.

RESULTS

Gene expression of core clock genes varied over 48 h in accordance with the circadian rhythm. Functional markers, except KI67, showed significant differences at time points of maximum fluctuation especially of ARNTL.

CONCLUSIONS

PDL fibroblasts express circadian clock genes. Our results suggest that genes associated with bone and periodontal remodeling are influenced by the circadian rhythm. Further research will have to refine the understanding of this influence for orthodontic treatment.

The effect of colostrum intake on osteoprotegerin and bone metabolic markers in the blood of newborn calves during the first week of life

The aim of this study was to elucidate the bone metabolic status after taking colostrum in newborn calves. Fourteen neonatal calves were randomly allocated to two groups fed either unheated or heated (60°C, 30 min) colostrum three times on the first day (2 l every 10 hr; 6 l in total). Heat treatment on colostrum was to reduce the bone metabolic markers assumed as heat-sensitive. The concentrations of four bone metabolic markers (the enzymes from bone cells or the bone collagen fragments) and a bone protective protein, osteoprotegerin (OPG), were measured in the blood of calves during a week after the birth and in the colostrum. The colostral concentrations of four bone metabolic markers were reduced by heating. Then those circulatory markers peaked after colostrum intake in the calves fed unheated colostrum; whereas those fed heated colostrum did not show such changes. However, the plasma tartrate resistant acid phosphatase 5b (TRAP5b) activity was transiently increased after taking colostrum in both groups. Meanwhile, heating did not decrease colostral OPG and there was no significant rise in the serum OPG concentrations after the first colostrum intake in both groups. The study revealed that the blood concentrations of studied bone metabolic markers depended on those colostral values except for TRAP5b. Based on the plasma TRAP5b changes, accelerated formation of premature osteoclast cells may be induced by colostrum intake. Meanwhile, colostral OPG absorption is less likely to impact on its circulating levels.

Effect of dietary difructose anhydride III supplementation on bone mineral density and calcium metabolism in late-lactation dairy cows

The aim of the present study was to examine the effect of 28 days of dietary difructose anhydride (DFA) III supplementation on calcium (Ca) metabolism in late-lactation dairy cows. Twenty-four multiparous pregnant Holstein cows were divided into two groups. The DFA group was fed total mixed ration (TMR) supplemented with 40 g of DFA III, and the control group was fed TMR only. The replenishment of bone Ca reserves was evaluated by measuring bone mineral density (BMD) and blood biochemical bone markers. Serum Ca concentrations, urinary Ca-to-creatinine (Cre) (Ca/Cre) ratios, and milk Ca concentrations were also analyzed. The BMD of the 4th caudal vertebra in the DFA group was higher than in the control group on day 28. With respect to bone markers, the ratios of undercarboxylated osteocalcin (ucOC) to osteocalcin (OC) in the DFA group were significantly lower than those in the control group on days 21 and 28. Milk Ca concentrations in the DFA group were also higher than those in the control group on days 14, 21, and 28, whereas serum Ca concentrations and urinary Ca/Cre ratios were unchanged in both groups. These results suggest that dietary supplementation with DFA III increased BMD and decreased serum ucOC/OC ratios in late-lactation dairy cows; this indicates that the replenishment of bone Ca reserves may be enhanced by dietary DFA III supplementation.

Serum activities of two bone markers in captive Asian elephants (Elephas maximus) at different ages

The blood biochemical analysis of bone markers could have a role in the early diagnosis of metabolic bone disease in animals; however, there is limited information on bone markers in captive Asian elephants (Elephas maximus). Serum samples from ten captive Asian elephants were obtained to clarify the relationship between age and the blood bone markers tartrate-resistant acid phosphatase isoform 5b (TRAP5b) and bone specific alkaline phosphatase (BALP). Serum TRAP5b and BALP activities were negatively correlated with age. A positive correlation was observed between TRAP5b activity and BALP activity. These results may contribute to the health management of captive Asian elephants.

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.

Changes in the plasma levels of several bone markers in newborn calves during the first two days of life

The fluctuations in the plasma levels of several bone markers were investigated in newborn calves. Experiment 1 monitored the postnatal changes in the plasma levels of tartrate-resistant acid phosphatase isoform 5b (TRAP5b), total alkaline phosphatase (t-ALP) and bone-specific alkaline phosphatase (BAP) in four calves. These markers increased significantly from 9−20 hr after the first colostrum-suckling compared with the values immediately after birth. Experiment 2 evaluated changes in the plasma TRAP5b, t-ALP, BAP and type I collagen cross-linked N-telopeptide (NTx) levels within 2 days post-birth in five calves with successful passive immunization via colostrum (non-deficient group) and five others with poor colostrum intake (deficient group). The non-deficient group had significantly higher plasma levels of the four parameters around 12 hr of life compared with the deficient group. The results suggest that the increase in plasma bone markers in calves in the first day of life is related to the colostrum intake.

Plasma fluctuation in estradiol-17β and bone resorption markers around parturition in dairy cows

Blood samples were obtained sequentially from 10 dairy cows around the time of parturition to assess plasma fluctuations in estradiol-17β (E₂) levels in association with those of several bone resorption markers. Plasma E₂ concentration increased sharply a few days prepartum and decreased quickly after parturition. In terms of bone resorption markers, the plasma level of tartrate-resistant acid phosphatase isoform 5b (TRAP5b) rose significantly, commencing 1 week prepartum, and was maintained at this level to a few days postpartum. The plasma concentration of carboxyterminal collagen cross-links of type-I collagen (CTx) increased significantly after parturition. These observations suggest that osteoclast-mediated bone resorption was activated after parturition when plasma E₂ concentrations decreased.

Set-up of a multivariate approach based on serum biomarkers as an alternative strategy for the screening evaluation of the potential abuse of growth promoters in veal calves

A chemometric class modelling strategy (unequal dispersed classes - UNEQ) was applied for the first time as a possible screening method to monitor the abuse of growth promoters in veal calves. Five serum biomarkers, known to reflect the exposure to classes of compounds illegally used as growth promoters, were determined from 50 untreated animals in order to design a model of controls, representing veal calves reared under good, safe and highly standardised breeding conditions. The class modelling was applied to 421 commercially bred veal calves to separate them into 'compliant' and 'non-compliant' with respect to the modelled controls. Part of the non-compliant animals underwent further histological and chemical examinations to confirm the presence of either alterations in target tissues or traces of illegal substances commonly administered for growth-promoting purposes. Overall, the congruence between the histological or chemical methods and the UNEQ non-compliant outcomes was approximately 58%, likely underestimated due to the blindness nature of this examination. Further research is needed to confirm the validity of the UNEQ model in terms of sensitivity in recognising untreated animals as compliant to the controls, and specificity in revealing deviations from ideal breeding conditions, for example due to the abuse of growth promoters.