ICTP Concentrations Research Articles

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

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

Abstract 21208: Association Between Serum Collagen and Myocardial Fibrosis Assessed by Magnetic Resonance Imaging: The Multi-Ethnic Study of Atherosclerosis

Introduction: C-terminal telopeptide of procollagen type I (ICTP) and N-terminal propeptide of procollagen type III (PIIINP) are two of the major collagen turnover markers representing collagen degradation and synthesis. Cardiac magnetic resonance (CMR) using delayed enhancement (DE) and T1 mapping, provides a tool for detection and quantification of focal scar and diffuse interstitial myocardial fibrosis. Hypothesis: Levels of the serum biomarkers of ICTP and PIIINP at baseline are associated with the presence of myocardial scar and diffuse interstitial fibrosis at the 10-year follow-up. Methods: Of 3000 participants in a case(CVD)-cohort study that measured PIIINP and ICTP in baseline, 827 subjects with had CMRI at follow-up. Participants were initially aged 45-84 years and free of clinical CVD. Baseline serum PIIINP and ICTP concentrations were assayed using radio-immunoassay. DE-CMRI assessed myocardial scar at 10-year follow-up, with T1 mapping indices of extracellular volume fraction (ECV), pre-contrast T1, and T1 at 25 minutes post-contrast measuring diffuse interstitial fibrosis. Logistic (DE scar vs. absence as a dichotomous outcome) or linear (continuous values of T1 indices as outcomes) multivariable regression analysis with ICTP and PIIINP levels weighted for the design as continuous exposures were performed with adjustment for ACC-AHA ASCVD risk score and glomerular filtration rate at baseline (Model 1) and follow-up (Model 2). Results: Mean (SD) ICTP was 3.1 ± 0.9 μg/L; PIIINP was 5.4 ± 1.3 μg/L; ECV was 27.3 ± 3.1 %; and T1 at 25’ was 517 ± 42 ms. Among 827 participants, 68 had myocardial scar. Increased ICTP and PIIINP levels at baseline were associated with the presence of myocardial scar at follow-up (Table 1). ICTP showed no association with T1 mapping indices. Conclusions: Increased levels of collagen turnover markers were independently associated with the presence of myocardial scar 10 years later, but not with diffuse interstitial fibrosis.

Association Between Vitamin D and Carboxy-Terminal Cross-Linked Telopeptide of Type I Collagen in Children During Growth Hormone Replacement Therapy.

Growth hormone and insulin-like growth factor-1 (IGF-1) play a crucial role in the regulation of bone turnover. Adequate vitamin D status supports proper bone remodeling, leading to normal longitudinal bone growth and normal peak bone mass. The aim of this study was to evaluate the association between serum 25-hydroxyvitamin D [25(OH)D] and carboxy-terminal cross-linked telopeptide of type I collagen (ICTP) in children and adolescents with growth hormone deficiency at baseline and during recombinant human growth hormone (rhGH) replacement therapy. The study was prospective and included 30 children and adolescents aged 5 to 17years. Concentrations of 25(OH)D, ICTP, and IGF-1 were measured at baseline and during the first year of rhGH therapy. Baseline serum 25(OH)D concentration correlated with ICTP concentrations during the first trimester of rhGH therapy (r=0.38, p<0.050); the correlation was stronger in the second trimester of therapy (r=0.6, p=0.002). We conclude that proper vitamin D status is important in reaching the adequate dynamics of bone remodeling during growth, which is essential to achieve a catch-up growth during rhGH therapy.

Impact of a chronic smoking habit on the osteo-immunoinflammatory mediators in the peri-implant fluid of clinically healthy dental implants

ObjectiveThe aim of this study was to evaluate the influence of chronic cigarette smoking on the profile of osteo-immunoinflammatory markers in the peri-implant crevicular fluid (PICF) from clinically healthy implants DesignsTwenty-five smokers and 23 non-smoker subjects with a unitary screwed implant-supported crown in the molar or pre-molar region were enrolled in this study. The implants should have been in functioning for at least 12 months, and the peri-implant tissue should be clinically healthy [probing depth (PD)<4mm with no bleeding on probing (BoP) and no evidence of radiographic bone loss beyond bone remodeling]. The levels of interferon (INF)-γ, interleukin (IL)-4, IL-17, IL-1β, IL-10, IL-6, IL-8, tumor necrosis factor (TNF)-α, matrix metalloproteinase (MMP)-2, MMP-9, osteoprotegerin (OPG), soluble receptor activator of nuclear factor-κβ ligand (RANKL), osteocalcin (OC), osteopontin (OPN), transforming growth factor (TGF)-β, and cross-linked telopeptide of type I collagen (ICTP) in the PICF were quantified by a multiplexed bead immunoassay. ResultsThe smokers presented reduced levels of IL-4, IL-8, and TNF-α compared with the non-smoker individuals (p<0.05). In addition, although lower OPG levels were detected in the PICF of the smokers, the RANKL/OPG ratio did not show a significant difference (p>0.05). Moreover, higher ICTP concentrations and a higher TH1/TH2 ratio were observed in the PICF of the smoker patients (p<0.05). No differences between the groups were observed for the other markers evaluated (p>0.05). ConclusionsSmoking habit modulate peri-implant cytokine profile, leading to reductions in IL-4, -8 TNF-α, and OPG levels and an increased ICTP and TH1/TH2 ratio in peri-implant crevicular fluid.

Serum carboxy-terminal telopeptide of type I collagen levels are associated with carotid atherosclerosis in patients with cardiovascular risk factors.

Carboxy-terminal telopeptide of type I collagen (ICTP) is generated through matrix metalloproteinase (MMP)-dependent type I collagen digestion, and has been widely utilized as a biomarker for bone turnover. The fact that atherosclerotic lesions are rich in both type I collagen and MMP-producing macrophages led to the hypothesis that serum ICTP concentrations may serve as a non-invasive clinical biomarker for atherosclerosis. Therefore, the association of serum ICTP concentrations with the maximum intima-media thickness (IMT) of carotid arteries, a surrogate index of systemic atherosclerosis, or brachial-ankle pulse wave velocity (baPWV) in patients with atherosclerotic risk factors was evaluated. A total of 52 male and 65 female (mean age: 62.8 yrs) patients without renal failure, malignancies or bone diseases known to affect serum ICTP concentrations were recruited. Patients with max IMTs ≥1.1 mm showed significantly higher serum ICTP concentrations compared with patients with max IMTs <1.1 mm (3.33 ± 0.97 vs 2.82 ± 0.65 ng/mL, p<0.05). Serum ICTP concentration was also positively correlated with max IMT (p<0.001) or baPWV values (p<0.05). Multivariate analyses also revealed that serum ICTP concentrations were correlated with max IMT (p<0.001; 95% CI 0.200 to 0.454). These results suggest that serum ICTP concentrations can be used as a non-invasive biomarker for systemic atherosclerosis.

Evaluation of Salivary Levels of Pyridinoline Cross Linked Carboxyterminal Telopeptide of Type I Collagen (ICTP) in Periodontal Health and Disease.

Traditional parameters (Pocket depth, bleeding on probing, clinical attachment loss, radiographic findings) have been used for a long time for the assessment of periodontal disease conditions. However, these parameters only indicate towards the periodontal damage that has already taken place but do not give any idea regarding the current status of the periodontal health or disease. Hence, the present study is aimed at evaluating the concentration of the bone biomarker ICTP in saliva, which can give a better real time assessment of periodontal health and disease. Forty three patients were selected and divided into three groups based on the recorded clinical parameters of probing pocket depth, attachment loss and bleeding on probing. Group I (Healthy, n = 11), Group II (Gingivitis, n = 17), Group III (Periodontitis. n = 15). Salivary samples were collected before scaling and root planning to avoid contamination by blood. ICTP levels were evaluated in the salivary samples by using enzyme linked immunosorbent assay (ELISA). Kruskal Wallis test was used to compare the mean ICTP level of the three groups. ICTP was detected in all the samples. Highest mean ICTP concentrations in saliva were obtained for group III (periodontitis group) and the lowest mean ICTP concentrations were seen in group I (healthy group). This suggests that the level of ICTP in saliva increases proportionally from periodontal health to diseased conditions (gingivitis & periodontitis). There is a substantial increase in the salivary concentration of ICTP in chronic periodontitis patients than in gingivitis and healthy patients. Salivary ICTP levels were the maximum in chronic periodontitis patients followed by gingivitis patients and the least in healthy individuals. ICTP may be considered as a biomarker in periodontal disease progression.

Validity of bone marker measurements for monitoring response to bisphosphonate therapy with zoledronic acid in metastatic breast cancer

Bone is the most common site of metastasis in breast cancer. Detection relies on imaging technology which is costly and can only be performed to a certain degree. Bone markers are non-invasive, inexpensive and may potentially serve as predictive and prognostic surrogate endpoints in detecting bone metastases and response to bisphosphonates. This study analyzed the value of the serum bone turnover markers PINP and ICTP for bone metastases in metastatic breast cancer patients receiving zoledronic acid. The results were compared with the serum levels of CEA and CA 15-3, and analyzed with respect to the number of bone metastases as well as clinical response. Forty patients with confirmed bone metastases who received chemotherapy and/or hormonal therapy and zoledronic acid i.v. q4 weeks participated in the present study. blood (5 ml) was collected at the start of the study and q3 months for a period of one year for the analysis of PINP, ICTP, CEA and CA 15-3 using radioimmunoassays and ELISA, respectively. Imaging of bone metastases was performed at the same time points. In 29 out of 40 patients, more than 3 bone metastases were confirmed by imaging and 11 out of 40 patients presented with 3 or less. At the start of the study, the median value for ICTP was 6 µg/l and for PINP 58.7 µg/l. At the end of the study the median values were 4.5 µg/l for ICTP and 21 µg/l for PINP. When patients were stratified into responders and non-responders, a decrease in both PINP (P<0.0001) and ICTP (P=0.048) was observed for the responders, while the level of ICTP (P=0.02) increased for the non-responders. Serum PINP and ICTP concentrations were significantly different when patients were stratified into groups of those having more than 3 bone metastases and 3 or less, respectively (P<0.05). CEA and CA 15-3 levels did not differ with respect to the number of bone metastases, while the tumor marker levels determined at the end of the study significantly distinguished responders from non-responders (P=0.002 and P=0.004). In conclusion, in contrast to serum tumor markers, the determination of PINP and ICTP allows inferences to the number of bone metastases and appears to be a useful tool for prediction and monitoring metastatic breast cancer patients undergoing bisphosphonate therapy with zoledronic acid for the treatment of bone metastases.

Perinatal collagen turnover markers in intrauterine growth restriction

Objective: To investigate bone and connective tissue collagen turnover in intrauterine growth restricted (IUGR) pregnancies, by determining circulating markers of type I collagen synthesis (carboxy-terminal propeptide of type I procollagen [PICP], representing bone formation) and degradation (cross-linked telopeptide of type I collagen [ICTP], representing bone resorption) as well as type III collagen synthesis (N-terminal propeptide of type-III procollagen [PIIINP], reflecting growth and tissue maturity).Methods: Plasma PICP, ICTP and PIIINP concentrations were measured in 40 mothers and their 20 asymmetric IUGR and 20 appropriate for gestational age (AGA) full-term fetuses and neonates on postnatal day 1-(N1) and 4-(N4).Results: Fetal PICP, fetal and N4 ICTP, as well as fetal, N1 and N4 PIIINP concentrations were higher in the IUGR group (p ≤ 0.038, in all cases). In both groups, maternal PICP, ICTP and PIIINP concentrations were lower than fetal, N1 and N4 ones (p < 0.001, in each case).Conclusions: Type I collagen turnover is enhanced in IUGR than AGA fetuses/neonates. Similarly, fetal/neonatal PIIINP concentrations are elevated in IUGR, probably due to stress, responsible for induction of tissue maturation, and/or to impaired excretory renal function, leading to reduced protein clearance. Fetal/neonatal PICP, ICTP and PIIINP concentrations are higher than maternal concentrations, possibly reflecting increased skeletal growth and collagen turnover in the former.

382 The Effect of Intrauterine Growth Restriction on Circulating Concentrations of Bone Collagen Markers in Full-Term Pregnancies

Background and aims: Intrauterine-growthrestriction (IUGR) is associated with impaired fetal skeletal development. We aimed to investigate the effect of IUGR on bone turnover in mother/infant pairs, by determining circulating bone markers of type I collagen in full-term IUGR and appropriatefor- gestational-age-(AGA) pregnancies. Methods: Circulating markers of bone formation (carboxy-terminal propeptide of type I procollagen- PICP) and resorption (cross-linked telopeptide of type I collagen-ICTP) were measured by EIA and RIA, respectively, in 40 mothers and their 20 asymmetric IUGR and 20 AGA full-term fetuses and neonates on postnatal day 1-(N1) and 4-(N4). Results: Fetal PICP, as well as fetal and N4 ICTP concentrations were higher in the IUGR group (p=0.036, p=0.038 and p< 0.001, respectively). In both groups, maternal PICP and ICTP concentrations were lower than fetal, N1 and N4 ones (p< 0.001 in each case). In a combined group, N4 PICP concentrations were elevated compared to N1 ones (p=0.012). Fetal ICTP concentrations were higher in females (p=0.008). Conclusions: Type I collagen synthesis and degradation are higher in IUGR fetuses/neonates. Thus, we may speculate that IUGR may affect bone mineral density and bone protein matrix in opposite directions. Higher fetal/neonatal PICP and ICTP concentrations, as compared to maternal ones, may be attributed to the high rate of skeletal growth in the former. The postnatal rapid increase in bone metabolism may account for the gradual elevation in PICP concentrations during the first days of life. Finally, the higher fetal ICTP concentrations in females may be explained by gender-related differences in bone mass.

Salivary MMP‐8, TIMP‐1, and ICTP as markers of advanced periodontitis

Salivary matrix metalloproteinase (MMP)-8 and -14, tissue inhibitor of matrix metalloproteinase (TIMP)-1, and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) were analysed aiming to detect potential markers of advanced periodontitis in saliva. In addition, we compared two MMP-8 detection methods, a time-resolved immunofluorometric assay (IFMA) and an enzyme-linked immunoassay (ELISA), to differentiate periodontitis subjects from controls. Concentrations of MMP-8, MMP-14, TIMP-1, and ICTP were analysed from salivary specimens of 165 subjects, including 84 subjects having at least 14 teeth with periodontal pocket (pocket depth > or =4 mm) and 81 subjects without pocket depth as their controls. Salivary MMP-8 detection by IFMA differentiated periodontitis subjects from controls more strongly than by ELISA. Salivary MMP-8, TIMP-1, and ICTP concentrations were higher in periodontitis subjects than those in controls. When only smokers were included in the analysis these differences were lost. The MMP-8/TIMP-1 ratio and the combination of MMP-8 and ICTP differentiated periodontitis and control groups even in smoker subjects. Salivary MMP-8, TIMP-1, ICTP, and especially their ratios and combinations are potential candidates in the detection of advanced periodontitis. Differentiating periodontitis and control subjects with salivary MMP-8 detection is dependent on the selected techniques.

Measurement of serum carboxyterminal cross-linked telopeptide of type I collagen concentration in dogs with osteosarcoma

To evaluate the usefulness of carboxyterminal cross-linked telopeptide of type I collagen (ICTP) concentrations for screening dogs for the presence of osteosarcoma. 32 client-owned dogs with osteosarcoma (27 dogs with osteosarcoma of the appendicular skeleton and 5 dogs with osteosarcoma of the axial skeleton) and 44 non-tumor-bearing control dogs. Serum was obtained from blood samples collected from dogs with osteosarcoma and from clinically normal dogs. The serum ICTP concentration was determined by use of a commercially available radioimmunoassay for ICTP. Mean +/- SD serum ICTP concentration in the tumor-bearing dogs was 7.32 +/- 2.88 ng/mL, and in clinically normal dogs, it was 6.77 +/- 2.31 ng/mL; values did not differ significantly. Mean serum ICTP concentration in dogs with appendicular osteosarcoma, compared with that of clinically normal dogs, was not significantly different. Mean serum ICTP concentration in dogs with axial skeletal tumor location was 10.82 +/- 2.31 ng/mL, compared with a value of 6.73 +/- 2.28 ng/mL in dogs with appendicular osteosarcoma. On the basis of the results of this study, serum ICTP concentrations are not a clinically useful screening tool for the detection of appendicular osteosarcoma in dogs. Despite the observation that serum ICTP concentration was higher in dogs with axial osteosarcoma than in clinically normal dogs, serum ICTP concentration determination is not a suitable screening test for osteosarcoma.

Efficacy of a genetically modified yeast phytase on phosphorus bioavailability in a corn‐soybean meal based diet for growing pigs

ABSTRACTWe investigated the efficacy of genetically modified yeast (GMY) phytase on phosphorus (P) bioavailability in growing pigs fed a corn–soybean meal based diet. Crossbred barrows were fed a P‐adequate, a low‐P or a P‐deficient diet containing 0.37, 0.27 and 0.14% non‐phytate‐P, respectively. The P‐deficient diet was supplemented with wild‐type yeast (WTY), Aspergillus (ASP) or GMY phytase at 750 PU per kilogram of food. Dietary ASP and GMY phytases increased plasma inorganic P (Pi) concentration and the apparent absorption of P, and decreased the concentration of a bone resorption marker, plasma type‐I collagen C‐terminal telopeptide (ICTP). Wild‐type yeast phytase also increased the apparent absorption of P, but the changes in plasma Pi and ICTP concentrations were not significant. Although the dietary Pi‐equivalencies based on plasma Pi and ICTP concentrations did not differ between WTY and ASP phytases, the equivalency of ASP phytase based on apparent absorption of P was higher than that of WTY phytase. The equivalency of GMY phytase calculated from each parameter was higher than that of WTY phytase, and did not differ from that of ASP phytase. These results suggest that efficacy of GMY phytase on P bioavailability was higher than WTY phytase, and as effective as ASP phytase in growing pigs.

Immunoassays for the measurement of IGF-II, IGFBP-2 and -3, and ICTP as indirect biomarkers of recombinant human growth hormone misuse in sport: Values in selected population of athletes

Insulin-like growth factor-II (IGF-II), insulin-like growth factor binding proteins (IGFBPs) -2 and -3 and C-terminal telopeptide of type I collagen (ICTP) have been proposed, among others, as indirect biomarkers of the recombinant human growth hormone misuse in sport. An extended intra- and inter-laboratory validation of commercially available immunoassays for biomarkers detection was performed. ELISA assays for total IGF-II, IGFBP-2 and IGFBP-3 (IGF-II/ELISA1: DSLabs, IGFBP-2/ELISA2: Biosource, and IGFBP-3/ELISA3: BioSource) and an EIA assay for ICTP (ICTP/EIA: Orion Diagnostica) were evaluated. The inter- and intra-laboratory precision values were acceptable for all evaluated assays (maximum imprecision of 30% and 66% were found only for the lowest quality control samples of IGF-II and IGFBP-3). Correct accuracy was obtained for all inter-laboratory immunoassays and for IGFBP-2 intra-laboratory immunoassay. The range of concentrations found in serum samples under investigation was always covered by the calibration curves of the studied immunoassays. However, 11% and 15% of the samples felt below the estimated LOQ for IGF-II and ICTP, respectively, in the zone where lower precision was obtained. Although the majority of evaluated assays showed an overall reliability not always suitable for antidoping control analysis, relatively high concordances between laboratory results were obtained for all assays. Evaluated immunoassays were used to measure serum concentrations of IGF-II, IGFBP-2 and -3 and ICTP in elite athletes of various sport disciplines at different moments of the training season; in recreational athletes at baseline conditions and finally in sedentary individuals. Serum IGF-II was statistically higher both in recreational and elite athletes compared to sedentary individuals. Elite athletes showed lower IGFBP-2 and higher IGFBP-3 concentration with respect to recreational athletes and sedentary people. Among elite athletes, serum IGFBP-3 (synchronized swimming), and ICTP (rhythmic gymnastics) concentrations were sport-dependent. Over the training season, within athlete variability was observed for IGFBP-2 in case of taekwondo and IGFBP-2 and -3 in case of weightlifting. Variations due to those aspects should be taken in careful consideration in the hypothesis of setting reference concentration ranges for doping detection.

Effects of antiepileptic drug therapy on vitamin D status and biochemical markers of bone turnover in children with epilepsy

Reports of decreased serum 25-hydroxyvitamin D (25-OHD) and altered bone metabolism associated with antiepileptic drug (AED) treatment are inconsistent and predominantly restricted to adults. In this cross-sectional observational study, the aim was to evaluate the influence of AED treatment on vitamin D status and markers of bone turnover in children with epilepsy. In 38 children taking AEDs and 44 healthy control subjects, blood samples were collected to determine the levels of serum 25-OHD, intact parathyroid hormone (iPTH), calcium (Ca), phosphate (P), bone alkaline phosphatase (BAP), osteocalcin (OC) and C terminal telopeptide of type I collagen (ICTP). More than 75% of the patients were vitamin D deficient (serum 25-OHD<20 ng/mL) and 21% of the patients had an insufficient vitamin D status (serum 25-OHD=20-30 ng/mL). In the patients, the serum levels of OC (p = 0.002) and BAP (p < 0.001) were significantly increased, but ICTP (p = 0.002) concentrations were significantly decreased compared with the control group. When patients where divided into two groups according to their medication (mono- or polytherapy), significantly lower 25-OHD (p = 0.038) and ICTP (p = 0.005) levels and elevated BAP (p = 0.023) concentrations were found in patients under polytherapy. An association between 25-OHD and the measured bone markers could not be determined. Our results indicate that the prevalence of vitamin D deficiency in epilepsy patients under AED treatment is high, especially under polytherapy, and alteration markers of bone formation and resorption suggests an accelerated skeletal turnover. The routine monitoring of serum 25-OHD and vitamin D supplementation on an individual basis should be considered.

The effect of carprofen on selected markers of bone metabolism in dogs with chronic Osteoarthritis

The purpose of this study was to investigate the effect of the nonsteroidal anti-inflammatory drug carprofen on bone turnover and to monitor the progress of chronic osteoarthritic dogs by measuring different bone markers and radiographic evalutation of the corresponding joints. For this purpose 20 dogs of different ages and weight were devided into 2 groups. Ten dogs were assigned to Group R, treated with carprofen, and ten dogs to Group C, which had no treatment. Radiographs of the affected joints were reviewed initially and six months later at the end of the experiment. Blood was taken 8 times from each dog. Four bone markers (Osteocalcin (OC), bone-specific alkaline phosphatase (bAP), carboxyterminal telopeptide of type I collagen (ICTP), serum CrossLaps (CTX) as well as 1,25-(OH)2-Vitamin D and parathyroid hormone (PTH) were monitored for 6 months. No significant group effects on bone markers were notied. In Group R a decrease in ICTP concentrations during the first three months and a significant decrease in CTX concentrations in the first two months of the study were observed. The bone formation marker bAP revealed a significant decrease throughout the experiment. Three dogs of Group C and one dog of Group R showed osteoarthritic progression in the radiographs. The significant decrease of CTX indicates that carprofentreatment could have a retarding effect on the progression of osteoarthritis. Radiological findings suggest that carprofen may delay osteophyte formation. The monitoring of focal metabolic processes as in bone of a osteoarthrotic joint is difficult, since the bone mass is very active and metabolic processes may have an influence on the monitoring.

Bone metabolism of milk goats and sheep during second pregnancy and lactation in comparison to first lactation

Substantial losses of skeletal tissue occur during late pregnancy and lactation. The goal of the present study was to follow these changes in pregnant and lactating goats and sheep, compare these two species during their second lactation, and also compare the results to the first lactation. Blood samples were collected from 12 adult dairy goats (Saanen goat) and sheep (Ostfriesen milk sheep) monthly during gestation, 2 or 3 days postpartum (pp), 2 weeks pp, 4 weeks pp, and then monthly during lactation until 7 months after parturition. Total bone mineral content (BMC) and total bone mineral density (BMD) were quantified using peripheral quantitative computed tomography (pQCT) at the same intervals as the blood was taken. Bone resorption was assessed in serum using two different domains of the carboxyterminal telopeptide of type I collagen (ICTP and crosslaps). Bone formation was quantified in serum with osteocalcin (OC) and bone-specific alkaline phosphatase (bAP). In addition, Ca and 1,25 dihydroxy vitamin D (VITD) were determined in serum. The same procedure was done during the first and second gestation and lactation. Mean ICTP and crosslaps concentrations of the two animal species showed an increase in the last month of gestation. In contrast, mean OC concentrations decreased slowly from the 2nd month of pregnancy until the first week pp. Also mean bAP activities showed a similar time course. Total BMC and BMD decreased until the first week pp in both species. Afterwards, BMC increased again during lactation. BMD levels of sheep and goats returned to prepartum levels during lactation. Vitamin D concentrations peaked in the first week pp. Only VITD concentrations in goats stayed elevated compared with prepartum values throughout the whole lactation during the second lactation. Around parturition and at the beginning of lactation, the bone resorptive phase of bone remodelling is accelerated, but is uncoupled from the process of bone formation. The mineral decrease in bone of these lactating animals seems to be reversible. Since during lactation, bone remodelling has bone resorption and formation phases tightly coupled. Interestingly, in these species, the bone loss in the second pregnancy and lactation measured with BMC and BMD is not as prominent as in the first lactation, but shows almost the same course, although the animals gave more milk in the second lactation. It seems that the organism adapts to the circumstances more easily in the second lactation compared to the first lactation in these two species.

Elevated prolidase activity in keloids: correlation with type I collagen turnover

Keloid pathogenesis involves an altered balance of extracellular matrix metabolism, mainly accumulation of type I collagen. This could be due to excessive synthesis or decreased degradation of matrix, or a combination of both processes. Prolidase, an imidodipeptide-cleaving cytosolic enzyme, plays an important role in the collagen catabolic process by recycling proline for collagen synthesis. Collagen accumulation in keloids is due to an imbalance in the steady state of collagen turnover. To investigate prolidase activity and its role in the steady state of collagen turnover between normal skin and keloid tissue and their derived fibroblasts. Ten sets of keloid and normal skin tissues and their derived fibroblasts were employed. Measurements were made of tissue prolidase activity, free proline level, and concentrations of the collagen synthesis product aminoterminal propeptide of type I procollagen (PINP) and the collagen degradative product carboxyterminal telopeptide of type I collagen (ICTP). Also, synthesis of collagens type I and III and matrix metalloproteinases 1 and 2 was investigated using Western blot analysis. Keloid tissues had a significant increase in prolidase activity, up to fourfold that in normal skin. The elevated prolidase activity was accompanied by an increase in tissue PINP and ICTP concentrations in keloid; in addition, the collagen turnover index (PINP/ICTP) was higher in keloids. The combination of elevated prolidase activity and associated higher collagen synthesis to degradation ratio in keloids suggests a possible metabolic process for the excessive accumulation of type I collagen in keloids.

The effects of first gestation and lactation on bone metabolism in dairy goats and milk sheep

The goal of the present study was to compare mobilization rate of calcium (Ca) from bone in pregnant and lactating goats and sheep. Blood samples were collected from goats and sheep monthly during pregnancy and at 1, 2, and 4 weeks postpartum (pp) and monthly during lactation until 6 months after parturition. Total bone mineral content (BMC) and total bone mineral density (BMD) were quantified using peripheral quantitative computed tomography at the same intervals as the blood was taken. Bone resorption was assessed by immunoassays quantitating two epitopes of the carboxyterminal telopeptide of type I collagen (ICTP, CTX). Bone formation was estimated by quantifying serum osteocalcin (OC) and bone-specific alkaline phosphatase (bAP). In addition, Ca and 1,25-dihydroxy vitamin D (1,25-VITD) concentrations were determined in serum. Mean ICTP and CTX concentrations of both animal species increased the first week after parturition. By the second week pp, the concentrations of both markers had decreased toward early gestation levels. In contrast, mean OC concentrations continually decreased until the 1st week pp. By the 2nd week pp, the mean concentrations of OC started to increase again. Mean bAP activities decreased during gestation and reached a nadir in the first week pp in goats and 4 weeks pp in sheep. Afterwards, mean bAP activities increased again in goats and sheep. 1,25-VITD concentrations peaked the first week pp and returned to early gestation values thereafter. Total BMC and BMD decreased from the 4th month of pregnancy until the 1st week pp in both species. Afterwards, BMC increased throughout the first month pp in goats and the first 3 months pp in sheep. BMD levels of sheep and goats returned to prepartum levels during lactation. The resorptive phase of bone remodeling is accelerated at parturition and in early lactation and is uncoupled from the process of bone formation. This allows the animal to achieve Ca homeostasis at the expense of bone. Increased bone remodeling during lactation may represent physiological mechanisms to help replace the maternal skeleton lost as the animal adapted to enormously increased Ca losses to the fetus and milk in late gestation and early lactation.

Biochemical markers of bone metabolism and risk of dorsal metacarpal disease in 2‐year‐old Thoroughbreds

Dorsal metacarpal disease (DMD) is a common problem in 2-year-old racehorses and results in loss of a significant number of days from training. Biochemical markers of bone cell activity measured early in the training season could have value for identifying 2-year-old Thoroughbred racehorses that develop DMD. To determine the association between serum concentrations of osteocalcin, the carboxyterminal propeptide of type I collagen (PICP) and the carboxyterminal cross-linked telopeptide of type I collagen (ICTP) measured early in the training season and the risk of DMD. Blood samples were collected from 165 two-year-old Thoroughbreds during late November/early December. Osteocalcin and PICP were measured as markers of bone formation, and ICTP as a marker of bone resorption. Training and veterinary records for each horse were monitored over the following training/racing season (10 months). Cases were defined as an episode where signs of DMD were sufficiently severe for a horse to miss at least 5 consecutive days of training. Classification tree and logistic regression analysis were used to identify the most important factors suitable for prediction of DMD risk. There were 24 cases of DMD during the season (14.6% cumulative incidence), with an average time to recognition of approximately 6 months (May). The earliest recognised case was in February and the latest in September. Osteocalcin and ICTP concentrations in the early stages of the training season were significantly higher in horses that subsequently developed DMD (P = 0.017 and 0.019, respectively). DMD cases were also significantly older compared to noncases (21.04 vs. 20.44 months, P = 0.023). Using a multivariable logistic regression model, it was possible to postulate a set of diagnostic rules to predict the likelihood of DMD injury during the season. This suggested that horses with ICTP concentrations above 12365 ug/l and older than 20.5 months are 2.6 times more likely to develop DMD. The measurement of the bone resorption marker ICTP could be useful for identification of 2-year-olds at increased risk of developing DMD. These findings, together with other strategies such as modification of training regimens, e.g. early introduction of short distances of high-speed exercise into the training programme, could help reduce the days lost to training as a result of DMD.

Elite volunteer athletes of different sport disciplines may have elevated baseline GH levels divorced from unaltered levels of both IGF-I and GH-dependent bone and collagen markers: a study on-the-field.

Seventy-seven Italian eliteathletes(42 M, 35 F, mean age +/- SE: 24.4-0.7 yr, age range: 17-47 yr) of different sport disciplines (sprinters, triathletes, middle-distance runners, road-walkers, cyclists, rowing athletes, skiers, roller hockey players, swimmers) were sampled on-the-field (before a training session) for the determination of basal GH, IGF-I, C-terminal cross-linked telopeptide of type I collagen (ICTP) and amino-terminal propeptide of type III procollagen (PIIINP) levels, two GH-dependent peripheral markers of bone and collagen turnover, respectively. Basal GH concentrations were significantly higher (p<0.001) in female (5.8 +/- 1.0 ng/ml) vs male athletes (1.8 +/- 0.5 ng/ml), with a large spread of values in either gender. Mean GH levels of athletes were significantly higher than those recorded in age-matched sedentary controls (females: 2.5 +/- 0.5 ng/ml, p<0.001; males: 0.5 +/- 0.2 ng/ml, p<0.05). Among female athletes, 7/35 had basal GH values higher than the upper limit of control values (>9.5 ng/ml), while among males 7/42 had values higher than the upper limit of male sedentary controls (>3.6 ng/ml). No significant differences in basal GH concentrations were found between females taking oral contraceptives (OC) and those who did not receive this treatment (5.0 +/- 2.1 vs 6.0 +/- 1.2 ng/ml). IGF-I levels (236.4 +/- 7.8 ng/ml) were in the normal range for age in all athletes (except for 1 athlete with slightly increased levels), no significant correlation being found between GH and IGF-I levels (R2=0.0393). Mean ICTP (4.6 +/- 0.2 ng/ml) and PIIINP (4.4-0.1 ng/ml) concentrations of elite athletes were not significantly different from those recorded in age and matched healthy sedentary subjects; 4 athletes showed increased PIIINP levels and 2 had increased ICTP levels. ICTP and PIIINP levels were positively correlated with chronological age (p<0.001), a positive correlation being also found between the two markers (p<0.001). On the contrary, no significant correlation was found between basal GH/IGF-I levels and ICTP/PIIINP levels. In conclusion, the present study demonstrates that: 1) elite athletes (particularly females), which have frequently increased basal GH on-the-field, have actually normal IGF-I levels; 2) ICTP and PIIINP levels of athletes are similar to those recorded in healthy sedentary, being significantly higher in younger subjects of both groups; 3) the presence of increased basal GH levels, being associated with normal IGF-I, ICTP and PIIINP levels, is probably the result of a transient GH peak in this study group. Further additional studies are requested to verify the possible use of these peripheral GH-dependent markers for detecting exogenous chronic administration of recombinant GH in athletes.