Serum PICP Research Articles

Abnormal bone turnover in monoclonal gammopathy of undetermined significance: analyses of type I collagen telopeptide, osteocalcin, bone-specific alkaline phosphatase and propeptides of type I and type III procollagens.

The main difference between monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) is the presence of lytic bone destructions in the latter. About 20% of MGUS patients develop MM, and histomorphometric studies have shown disturbed bone turnover rates in some of these patients. This study was performed in order to evaluate whether serum analyses of the C-terminal telopeptide of type I collagen (ICTP), as a reflector of bone degradation, and of osteocalcin, bone-specific alkaline phosphatase (bAP) and the C-terminal propeptide of type I procollagen (PICP), as markers of bone formation, might give information on disturbances of bone metabolism in MGUS. Furthermore, serum N-terminal propeptide of procollagen III (PIIINP) might give information on disturbances in collagen III metabolism in the bone marrow. In the 35 patients examined, serum ICTP was elevated in 12 patients (34%), serum PIIINP elevated in 6 patients (17%), serum osteocalcin elevated in 11 patients (31%), serum bAP elevated in 6 patients (17%), and serum PICP elevated in 4 patients (11%). Serum ICTP correlated significantly with PIIINP (r = 0.72, p < 0.001), and with serum osteocalcin (r = 0.57, p < 0.001) and serum bAP (r = 0.51, p = 0.002). These findings indicate disturbances of bone turnover and affected collagen metabolism in some MGUS patients. Follow-up observation may reveal any prognostic value of these findings.

Serum and urinary markers of types I and III collagen turnover during short-term prednisolone treatment in healthy adults

Wolthers OD, Heuck C, Hansen M, Kollerup G. Serum and urinary markers of types I and III collagen turnover during short-term prednisolone treatment in healthy adults. Scand J Clin Lab Invest 1997; 57: 133-140.During recent years new sensitive serum and urinary makers have been introduced for assessment of collagen turnover. The aim of the present study was to assess whether short-term prednisolone treatment is associated with any adverse effects on serum levels of the type I collagen synthesis marker, the carboxy terminal propeptide of type I procollagen (PICP); on the type I collagen degradation marker in serum, the carboxy terminal pyridinoline cross-linked telopeptide of type I collagen (ICTP); on a serum marker of type III collagen synthesis, the aminoterminal propeptide of type III procollagen (PIIINP), or on the type I collagen degradation markers urinary pyridinoline (PYD) and deoxypyridinoline (DPD) concentrations. We studied 12 men and 8 premeno-pausal women aged 19-45 years (mean 31). All subjects were healthy. The design was a randomized double-blind, placebo-controlled parallel group study with a 2-day run-in, a 3-day treatment period and a 4-day run-out. During run-in and run-out no medication was given. During the treatment period the subjects took either prednisolone, 40 mg per day, or placebo. Blood and urine were collected at the last day of each period. The intergroup comparisons of run-in treatment values showed that prednisolone suppressed PICP (p<0.001) and PIIINP (p<0.001). PICP levels remained suppressed during run-out, whereas PIIINP returned to pretreatment levels. No prednisolone-induced effects on ICTP or on urinary PYD or DPD were detected by the intergroup comparisons. Short-term prednisolone treatment is associated with suppressive effects on type I and III collagen turnover. Whether serum PICP is more sensitive than urinary PYD and DPD for detection of short-term suppressive effects on type I collagen turnover remains to be further evaluated

Serum markers of bone metabolism in multiple myeloma: prognostic value of the carboxy-terminal telopeptide of type I collagen (ICTP). Nordic Myeloma Study Group (NMSG).

This study was performed to evaluate the prognostic significance of serum markers of bone and collagen metabolism in multiple myeloma. Serum C-terminal telopeptide of type I collagen (ICTP) reflects degradation of bone, whereas serum osteocalcin, together with serum C-terminal propeptide of procollagen type I (PICP) and serum bone-specific alkaline phosphatase (bAP) reflect synthesis of bone matrix. The N-terminal propeptide of procollagen type III (PIIINP) in serum reflects synthesis of type III collagen. We analysed frozen sera from 109 patients with newly diagnosed multiple myeloma. Serum ICTP was elevated (> 5.0 micrograms/l) in most patients (median 6.6 micrograms/l range 1.4-29.4 micrograms/l). Serum PIIINP was elevated (> 4.2 micrograms/l) in 46% (median 4.0 micrograms/l, range 1.4-20.1 micrograms/l). Serum PICP was generally within the reference limits, whereas serum osteocalcin and serum bAP were elevated in 19% and 37%, respectively. Serum ICTP correlated with serum PIIINP, serum beta 2-microglobulin (beta 2m), serum calcium, performance status, and stage. In univariate analysis, the test variables serum ICTP (P = 0.026) and serum osteocalcin (P = 0.036) were found to be of prognostic value, but PIIINP, PICP, or bAP in serum were not. Serum ICTP and serum beta 2m had a similar prognostic value. In multivariate analysis, serum calcium showed the highest prognostic significance, and serum beta 2m was the only other variable of independent prognostic value. However, in normocalcaemic patients, serum ICTP showed the highest prognostic significance, followed by serum osteocalcin. Thus, the serum levels of ICTP and osteocalcin seem related to bone turnover and calcium metabolism, and provide further information about myeloma activity, particularly in normocalcaemic patients.

Dose-dependent effects of recombinant human growth hormone on biochemical markers of bone and collagen metabolism in adult growth hormone deficiency

Administration of growth hormone (GH) to patients with growth hormone deficiency (GHD) has beneficial effects, but so far has been employed only empirically. We have, therefore, investigated the dose-dependent effect of GH on target tissue by studying biochemical markers of bone and collagen turnover in GHD. Then patients with GHD (nine males and one female aged 21-43 years, mean age 28 years) participated in the study. Growth hormone deficiency was defined as a peak serum GH response of less than 15 mU/l in two provocation tests. After a 4-week run-in period, the study population received increasing doses of GH at 4-week intervals (1, 2 and 4 U/m2). Blood samples were collected in the fasting state at 7.00 h on the last day of each period and assayed for serum levels of osteocalcin (S-BGP), bone alkaline phosphatase (B-ALP), C-terminal propeptide of type I collagen (S-PICP), carboxy-terminal pyridinoline cross-linked telopeptide of type I collagen (S-ICTP) and N-terminal propeptide of type III collagen (S-PIIINP). Following replacement therapy, serum insulin-like growth factor I and insulin-like growth factor binding protein 3 increased sequentially with time (p < 0.001 and p < 0.001, MANOVA) and the values were elevated significantly over baseline levels after treatment with 1 U/m2. Serum BGP values were below normal at the start of the study and increased gradually following GH treatment to levels in the low-normal range. Baseline values for serum bone alkaline phosphatase (B-ALP), PICP and PIIINP were within the normal range. The collagen parameters increased with GH replacement (p < 0.001, MANOVA) to levels above normal, whereas B-ALP stayed within normal limits. Serum ICTP values were elevated above the normal range at baseline, indicating increased bone resorption in GHD. A linear increase in values was observed with GH treatment (p < 0.001, MANOVA). Serum ICTP did not correlate significantly with the bone formative parameters but was correlated positively to PIIINP. The sensitivity of S-ICTP as a bone resorptive marker is thus questioned. In conclusion, a dose-dependent increase in markers of growth hormone metabolism and in biochemical markers of both bone and non-bone collagen synthesis was seen following incremental doses of GH in GHD.

Significance of serum levels of type I procollagen peptide and intact osteocalcin and bone mineral density in patients with ossification of the posterior longitudinal ligaments.

This study was performed to evaluate the correlation between serum biochemical marker levels of bone metabolism and bone mineral density (BMD) in patients with ossification of the posterior longitudinal ligaments (OPLL). In addition, the efficacy of these markers in the prediction of the progression of OPLL was also examined. In 40 patients with OPLL, and in age- and gender-matched controls (n = 36), the levels of C-terminal extension peptide of type I procollagen (PICP) and intact osteocalcin were quantitated by a sandwich enzyme-linked immunosorbent assay as serum markers of bone formation. BMD of the whole body was measured using dual-energy X-ray absorptiometry. Serum PICP and intact osteocalcin levels were significantly increased in patients with OPLL. There was a significant correlation between serum bone formation marker levels and BMD in both the OPLL and the control groups. Patients with radiological progression of OPLL showed a level higher than the mean + 2 SD of controls in PICP, intact osteocalcin, and BMD. In addition, the levels of serum PICP and intact osteocalcin increased in correspondence with the progression of OPLL without statistical significance. In patients without any growth of OPLL, however, all the parameters were below the mean + 2 SD of controls. Thus, aggravation of bone formation activity was suggested to be closely correlated with the development of OPLL. In addition, serial measurements of these parameters might be useful for estimating the progression of OPLL.

Normal serum indices of bone collagen biosynthesis and degradation in small for gestational age infants.

Serum carboxyterminal propeptide of type I procollagen (PICP) and cross-linked carboxyterminal telopeptide of type I collagen (ICTP), new markers of bone collagen type I biosynthesis and degradation, have not been studied in small for gestational age (SGA) infants. In an earlier study, we found a lower bone mineral content (BMC) and decreased serum osteocalcin in SGA than in appropriate for gestational age (AGA) infants, supporting the thesis that decreased fetal bone formation is a cause of lower BMC in SGA. In view of the role of insulin-like growth factor-I (IGF-I) in the regulation of collagen type I synthesis and degradation, and low serum IGF-I concentrations in SGA infants, we hypothesized that serum PICP would be lower and serum ICTP would be higher in SGA than in AGA infants, reflecting decreased bone collagen type I biosynthesis or enhancement of bone collagen type I degradation in SGA. We studied 19 term SGA and 38 term AGA infants that were matched specifically 1:2 by gestation and birth month. There were no differences between SGA and AGA infants in serum PICP nor ICTP concentrations. Serum ICTP was correlated with osteocalcin and with PICP in SGA infants but not in AGA infants. Thus, serum biochemical indices of bone collagen type I biosynthesis and degradation in term SGA infants are similar to those in term AGA infants. These findings are not consistent with the thesis of altered fetal bone collagen type I biosynthesis or degradation in SGA. We suggest that the reduced bone mineral content in SGA infants is predominantly related to a lower supply of minerals rather than defective regulation of bone collagen type I metabolism.

Serum biochemical markers of bone turnover in healthy infants and children.

Serum osteocalcin (OC), bone alkaline phosphatase (BAP), carboxyterminal propeptide of type I procollagen (PICP), carboxyterminal telopeptide of type I collagen (ICTP), parathyroid hormone (PTH) and 1,25 dihydroxyvitamin D [1,25(OH)2D] were measured in 241 normal infants and children (134 males and 107 females aged 1.9 months-14 years, 1.8 months-12 years, respectively). Regarding the analysis of data for children above 2 yrs, we chose data with the following normalization: data/body surface x standard body surface, to eliminate biological variations not exclusively related to chronological age. The increase in serum OC occurred at the expected age of growth spurts in both sexes: in the first year of life OC values (mean +/- SD) were 82.6 +/- 34.3 and 60.2 +/- 32.9 OC ng/ml in males and females, respectively; during puberty, peak values occurred at the age of 10-12 yrs in girls (76.6 +/- 25.8) and at the age of 12-14 yrs in boys (113 +/- 48.3). Furthermore, significant positive correlations with age were found for males from 2 to 14 yrs (p < 0.00001) and for females from 2 to 12 yrs (p < 0.001). Elevated levels of BAP occurred in the first year, 70.4 +/- 28.2 and 71.8 +/- 28.5, and in the second year, 69.4 +/- 26.7 and 67.4 +/- 33.8 ng/ml, for males and females, respectively. For children older than 2 yrs, a positive correlation with age (p < 0.01) was found for females only, with a peak value of 67.2 +/- 13.9 at the age of 10-12 yrs. For ages 2-14 yrs the reference values (mean +/- 2SD) were 15.5 - 90.3 and 17.2 - 95.2 ng/ml for males and females, respectively. The highest PICP levels (1354 +/- 680 ng/ml in males and 1041 +/- 766 in females) were observed in infants less than 1 year of age, decreasing by about 60% at the age of 2. There was no significant change in serum PICP for children older than 2 yrs with values covering a range (mean +/- 2SD) of 52 - 544 and 18 - 546 ng/ml in males and females, respectively. Similarly, the highest ICTP values were seen in infants younger than 1 year (29.7 +/- 11.7 and 29.5 +/- 20.1 ng/ml in males and females, respectively). In the ages from 2 to 14 yrs there did not seem to be any systematic age-correlated changes, with values covering a range (mean +/- 2SD) of 6.06 - 24.5 in boys and 6.84 - 22.9 ng/ml in girls. Serum PTH concentrations (mean +/- SD) in infancy were 27.2 +/- 19.3 pg/ml for males and 25.8 +/- 10.8 for females. Normal ranges (mean +/- 2SD) in the older group were 5.77 - 53.1 and 6.71 - 57.3 pg/ml for males and females, respectively. Serum 1,25(OH)2D presented values of 47.3 +/- 28.1 and 38.7 +/- 18.2 pg/ml under 2 yrs for males and females, respectively. The ranges (mean +/- 2SD) in children above 2 yrs were 9.5 - 101 pg/ml in boys and 10.9 - 88.4 in girls. The results of this study contribute to the establishment of reference values in normal children for these biochemical assays; these reference values are needed when the above biological markers will be applied in the monitoring of metabolic bone diseases.

Clinical usefulness of serum carboxyterminal propeptide of type I procollagen and pyridinoline cross-linked carboxyterminal telopeptide of type I collagen in patients with prostate cancer.

A study was undertaken to evaluate the clinical usefulness of measurements of serum concentrations of the carboxyterminal propeptide of type I procollagen (PICP) and the pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) as parameters of bone metastasis in patients with prostate cancer. Serum PICP, ICTP, prostate-specific antigen (PSA), and alkaline phosphatase (ALP) were evaluated in 82 patients with prostate cancer and 26 patients with benign prostatic hyperplasia (BPH). These markers were measured serially in 16 prostate cancer patients during treatment. The serum levels of PICP, ICTP, ALP, and PSA were significantly higher in prostate cancer patients with bone metastasis than in patients with either BPH or prostate cancer without bone metastasis. Although the rate of detection of bone metastasis with PICP and ICTP was slightly lower than that with PSA determined by the receiver operating characteristic curve, the correlation between both PICP and ICTP and the extent of disease was much higher than that of PSA. PICP and ICTP levels varied with ALP and PSA levels, the patient's clinical course after the start of endocrine therapy and the progression of bone metastasis. The levels of PICP and ICTP did not change substantially in patients who developed local regrowth or lymph node metastasis, and decreased as bone metastases responded to radiotherapy. PICP and ICTP thus reflect the metastatic burden in bone and are useful for monitoring the response of bone metastasis to therapy.

Bone density change and biochemical indices of skeletal turnover

Although biochemical markers of skeletal turnover cannot replace bone density scanning for the diagnosis of osteoporosis, it is thought that they may help add to prediction of fracture risk and help determine adequacy of osteoporosis therapy. Nevertheless, whether biochemical markers in the serum or urine can predict individual rates of bone loss in the spine or hip region is unknown. We studied a heterogeneous group of women (n = 81) who were premenopausal, untreated postmenopausal, and estrogen-treated postmenopausal with baseline determination of body mass index (BMI), calcium intake, biochemical measurements, and serial bone densitometry over 3 years. Serum assays included bone Gla protein (BGP), total and bone-specific alkaline phosphatase (AP, BSAP), carboxyterminal propeptide of type I procollagen (PICP), carboxyterminal telopeptide of type I collagen (ICTP) and tartrate-resistant acid phosphatase (TRAP). Urine assays included hydroxyproline (OHP), calcium, total pyridinoline, and total deoxypyridinoline. Individual biochemical markers and calcium intake were modestly correlated with bone density changes but were inconsistent regarding the spine versus the hip. All of the formation variables were significantly correlated to spine density change (r = -0.24 to -0.49) whereas the only resorption variable that correlated was urine OHp/Cr (r = -0.31). The only formation variable that correlated with hip density change was serum PICP whereas all of the resorption variables except serum TRAP were correlated (r = -0.23 to -0.35). "High turnover" individuals were defined at those with levels of biochemical variables at least 1 SD above the mean young normal for each variable. Higher bone loss rates were seen in this group for several of the turnover markers compared with bone loss rates in all other individuals. However, the sensitivity of this "high turnover" status for identifying high bone losers did not exceed 60% for any of the variables. In untreated postmenopausal women, a model using urine OHp, serum ICTP, serum BSAP, and calcium intake was able to predict 42% of the variance of change in BMD of the lumbar spine. A model using BMI, serum ICTP, and serum BGP could predict 32% of the variance of change in BMD of the femoral neck. No combination of markers could predict variance in bone density change at either site in estrogenized women (premenopausal and estrogen-treated postmenopausal). We conclude that measuring individual serum and urine markers of bone turnover cannot accurately predict bone loss rates in the spine and hip; however, combinations of demographic and biochemical variables could predict some of the variance in untreated postmenopausal women. Biochemical markers cannot replace serial bone densitometry for accurate determination of change in bone mass at the most clinically relevant sites.

Bone metabolic marker levels in residents of a rural community in Japan

The sex and age distributions of values of bone metabolic markers were investigated among the inhabitants of a mountain village in Wakayama Prefecture, Japan. The survey was carried out in Miyama village, which has a population of 2372 (1129 men and 1243 women) based on the resident registration of 1990. In this village, all residents aged 40 years or over are eligible for general mass health examinations once a year. In the present study, bone metabolic markers were measured in recruited participants in the health examinations conducted in 1992 in each of four age strata: 40–49, 50–59, 60–69, and 70–79 years. The bone metabolic markers measured were osteocalcin (BGP), carboxyterminal peptide of type I procollagen (PICP), alkaline phosphatase (ALP), crosslinked carboxyterminal telopeptide region of type I collagen (ICTP), pyridinoline (Pyr), and deoxypyridinoline (D-Pyr). In men in their 40s, 50s, 60s, and 70s, the mean serum BGP level was 6.15, 7.04, 7.65, and 7.69 ng/ml, respectively; the level in men in their 40s was significantly lower than that in those in their 60s. The serum PICP level in the 40- to 49-year age group was significantly higher than those in the other age groups, while that of serum ICTP tended to increase with age. The mean values of urinary Pyr and D-Pyr were higher in the older groups. In women, the mean values of all bone metabolic markers were all higher among those in the 50–59, 60–69, and 70–79 age groups compared to those in the 40–49 age group. These findings suggest that active bone metabolic turnover occurs even in the older age groups in both men and women.

Increased degradation of type I collagen in patients with inflammatory bowel disease.

To assess the mechanisms of osteopenia in inflammatory bowel disease (IBD), the serum markers of bone formation (osteocalcin and carboxyterminal propeptide of type I procollagen (PICP)) and bone degradation (carboxyterminal telopeptide of type I collagen (ICTP)), the bone mineral density (BMD) of the lumbar spine and the proximal femur and calcium intake of 150 unselected IBD patients and 73 healthy controls were investigated. The patients had higher ICTP values (3.69 (SD 1.40) microgram/l) than the healthy controls (3.25 (1.00) microgram/l, p = 0.035), but no differences in serum PICP and osteocalcin between these groups were detected. In the patients, the ICTP, PICP, and osteocalcin values did not have any significant correlation with BMD, but the patients with ICTP values above 3.6 microgram/l had significantly lower Z scores than those with lower ICTP. In the controls, however, a positive correlation between serum ICTP and BMD was found. The ulcerative colitis patients with total colitis had higher values of ICTP (3.96 (1.58) microgram/l) than those with a left sided disease (3.04 (0.86) micrograms/l, p = 0.009). The patients with a history of clinically active disease (n = 20) had higher ICTP (4.58 (1.55) microgram/l) and osteocalcin (12.56 (5.64) microgram/l) values than the patients (n = 130) with quiescent disease (ICTP 3.56 (1.33), p = 0.002, and osteocalcin 9.76 (3.62), p = 0.017). Increased serum osteocalcin, PICP, and ICTP concentrations and reduced BMD Z scores were found in a subgroup of Crohn's disease patients with a history of an active disease (n = 11). Raised serum ICTP and normal values of osteocalcin and PICP in IBD patients show increased breakdown of type I collagen without a compensatory increase in its synthesis suggesting an increased rate of bone degradation as a probable mechanism for osteopenia in IBD. Raised ICTP values are related to reduced bone mineral densities.

Concentrations of serum markers of type I collagen synthesis and degradation and serum osteocalcin in maternal and umbilical circulation.

Measurement was made of the serum carboxyl-terminal propeptide of type I procollagen (PICP), carboxyl terminal cross-linked telopeptide of type I collagen (ICTP) and osteocalcin in 17 full-term mother-infant pairs and 17 age-matched nonpregnant women. Serum PICP and ICTP of term women at the time of delivery were significantly higher (P < 0.025, P < 0.01, respectively) and serum osteocalcin was significantly lower (P < 0.001) than in nonpregnant women. The ratio of PICP to ICTP was essentially the same for term and nonpregnant women. Serum PICP, ICTP, and osteocalcin were virtually the same in the umbilical arteries and vein. PICP, ICTP, and osteocalcin were much higher in fetal than maternal circulation (P < 0.001). The fetal levels of these proteins were not correlated with maternal levels, nor with birth weight. Thus, during pregnancy, either osteoclastic or osteoblastic activity would appear to increase slightly, but the balance between bone formation and resorption is maintained. During fetal life, bone turnover may be greatly accelerated and bone metabolism may occur independently of maternal bone metabolism.

Serum levels of carboxyterminal propeptide of type I procollagen and pyridinoline crosslinked telopeptide of type I collagen in normal children and children with growth hormone (GH) deiciency during GH therapy

In this study, we investigated age-related changes in serum levels of both the carboxyterminal propeptide of type I procollagen (PICP) and the pyridinoline crosslinked telopeptide of type I collagen (ICTP) to elucidate bone formation and resorption, respectively, in 200 normal Japanese children (141 males and 59 females, age range 0–16 years). Furthermore, to clarify the effect of GH on bone turnover, we measured serum PICP and ICTP in 26 growth hormone (GH)-deficient children (20 males and 6 females, age range 4–15 years) who showed significant bone growth during recombinant human GH therapy. In the normal children, the curves for age-related changes in both serum PICP and ICTP levels almost paralleled that of the standard height velocity curve in both sexes. The serum levels of both peptides were higher than those in adults, and the peak increases corresponded with the timing of the adolescent growth spurt. Furthermore, the serum levels of PICP and ICTP were significantly correlated with the height velocity. In the GH-deficient patients, the serum ICTP levels before GH therapy were lower than those in age- and sex-matched controls. Both PICP and ICTP levels in serum increased significantly at the beginning of GH therapy. Furthermore, the percent increase in PICP after 1 month of GH treatment was positively correlated with the percent increase in height velocity during 1 year of GH treatment. These results suggest that bone turnover is high in normal children, particularly during infancy and puberty, and that GH could affect bone resorption as well as formation. The serum level of PICP is a potential marker for predicting the growth response to long-term GH therapy. ( Bone 17:397-401; 1995)

Collagen derived serum markers in carcinoma of the prostate.

Three new collagen markers deriving from the collagenous matrix, e.g. carboxyterminal propeptide of type I procollagen (PICP), carboxy-terminal pyridinoline cross-linked telopeptide of type I collagen (ICTP), and aminoterminal propeptide of type III procollagen (PIIINP) were used for the diagnose of prostatic bone metastases. Blood samples were obtained prior to biopsy or TURP. Serum PICP, PIIINP and ICTP were measured with commercial available RIAs and PSA by IRMA. Serum PSA was increased in patients with local prostatic cancer compared with patients with hyperplasia (p < 0.05). The level of PIIINP, ICTP, and PICP did not differ between these two groups. In patients with metastatic prostatic cancer all five markers were increased compared to the level measured in patients with localized cancer (p < 0.0001). All variables showed a significant positive relationship with alkaline phosphatase. The sensitivity ranged from 0.53 to 0.62 and specificity from 0.91 to 0.95. The sensitivity for alkaline phosphatase and PSA was 0.69 and 0.66 and specificity 0.91 and 0.68, respectively.

Carboxy-terminal propeptide of human type I collagen and pyridinium cross-links as markers of bone growth in infants 1 to 18 months of age

Serum carboxy-terminal propeptide of human type I collagen (PICP) concentrations, as a marker for bone formation, and urinary pyridinium (Pyd) cross-link concentrations, as a marker of bone resorption, were determined in 66 healthy infants aged 1-18 months who are being studied longitudinally. We hypothesized that there would be a positive correlation of growth velocity, increase in bone area, and bone mass accretion rates with PICP and Pyd cross-link concentrations. Since osteocalcin is currently used as a marker of bone formation, serum osteocalcin concentrations were also measured. Mean serum PICP and urinary Pyd cross-link concentrations were significantly greater than adult concentrations. Future growth velocity, increase in bone area, and bone mass accretion rates were not associated with PICP, Pyd cross-link, or osteocalcin concentrations. Growth velocity during the 3 months preceding sample collection correlated with serum PICP, Pyd/kg, and osteocalcin concentrations (r = 0.474, p < 0.001; r = 0.379, p < 0.001; and r = 0.516, p < 0.001, respectively). Previous increase in bone area correlated with serum PICP concentrations (r = 0.359, p = 0.01). The relationship between the infant's previous bone mass accretion rate and PICP was of borderline significance (r = 0.281, p = 0.055). In summary, normative data for PICP, Pyd cross-link concentrations, and parameters of bone growth are provided for infants 1-18 months of age and indicate that these markers reflect past and current bone metabolism and may be helpful in monitoring bone disorders in infants.

Serum Levels of the Carboxy-Terminal Cross-Linked Telopeptide of Type I Collagen and Laminin Are Elevated in Graves' Disease but Not in Toxic Nodular Goiter

We determined serum levels of laminin, carboxyterminal cross-linked telopeptide, and carboxyterminal propeptide of type I collagen (ICTP and PICP) in 27 patients with Graves' disease (GD) and in 31 patients with toxic nodular goiter (TNG). Elevated levels of soluble laminin and ICTP were observed in patients with GD prior to treatment (mean ± SD concentration 1444 ± 404 and 8.6 ± 3.5 ng/ml, respectively), compared to patients with TNG (476 ± 103 and 4.2 ± 1.5 ng/ml) and normal controls (492 ± 112 and 3.1 ± 1.3 ng/ml, n = 34). In contrast, serum PICP concentrations were not different between patients with GD or TNG and normal controls. In GD patients serum ICTP and laminin levels decreased during thiamazole treatment and normalized within 4 and 8 weeks of therapy. There was no correlation between serum ICTP and laminin levels and serum levels of thyroid hormones and/or autoantibodies, respectively. Serum ICTP and laminin could be markers for alterations of extracellular matrix during GD and release of matrix components in the circulation and/or reflect an impaired clearance.

Effects of Short-Term Maximal Work on Plasma Calcium, Parathyroid Hormone, Osteocalcin and Biochemical Markers of Collagen Metabolism

Physical activity is most probably an important factor to increase bone mass. The exact mechanisms by which this takes place are not completely understood. During the last years methods have become available making it possible to study the metabolism of type I collagen in bone in more detail. In this study seven male athletes were studied before and after a short-term maximal work (a modified Wingate test at a retardation of 7.5% of body weight) during 30 seconds. Blood samples were drawn before the test and 5 and 60 minutes after. Serum concentrations of type I procollagen carboxyterminal propeptide (PICP) and carboxyterminal telopeptide of type I collagen (ICTP) were measured, as were serum calcium, parathyroid hormone and osteocalcin. Serum PICP and ICTP reflect synthesis and degradation of type I collagen, respectively and mainly bone collagen metabolism. A significant increase of ionized calcium and lactate was noted while PTH and total serum calcium did not change. No significant alterations of either ICTP, PICP or osteocalcin were registered. We conclude from this study that the short-term maximal work performed by means of the modified Wingate test failed to show any significant changes in bone metabolism (osteocalcin and metabolites of type I collagen). A short experimental period and lactacidosis might contribute to the unaltered bone metabolism. The results mainly indicate that there is no pool of bone biochemical markers in young athletic males that is washed out by short bursts of intense exercise.

Influence of age, sex, and insulin on osteoblast function: osteoblast dysfunction in diabetes mellitus.

The osteoblast function was evaluated in normal and diabetic children and adults by measurements of the serum concentration of the carboxy-terminal extension peptide of procollagen (PICP), total and skeletal alkaline phosphatase (ALP), and osteocalcin. Moreover, the osteoblast-stimulating growth factor, insulin-like growth factor I (IGF-I), was measured in the same samples. In normal children (n = 420; age, 5-20 yr), a marked pubertal increase of serum IGF-I (peak values at age 14-16 yr in both sexes), osteocalcin, and total and skeletal ALP (peak values earlier in girls than in boys) and a small increase in PICP were observed. All osteoblast markers and IGF-I were markedly lower in normal adults (n = 229; age, 21-69 yr) than in children. All osteoblast parameters showed a high degree of correlation (P < 0.001) with each other. In adolescents (n = 104) treated for insulin-dependent diabetes mellitus (IDDM), serum IGF-I (-19%), osteocalcin (-28%), and skeletal ALP (-28%) were markedly decreased, whereas total ALP was significantly increased (29%), and serum PICP remained normal. In adult IDDM (n = 125), both serum IGF-I (-41%) and osteocalcin (-24%) were decreased, but skeletal ALP and PICP remained normal. A similar abnormality in serum IGF-I and osteocalcin was observed in white (n = 61) and Pima Indian (n = 16) non-IDDM patients. The concentration of skeletal ALP was highly significantly correlated (r > or = 0.9) with total ALP in both normal and diabetic subjects, but the slope of the regression was significantly different, indicating the presence of other, probably intestinal, ALP in all types of diabetes. In conclusion, the osteoblast function is significantly decreased in diabetic patients, which can best be characterized as a maturation defect, since the early osteoblast marker, PICP, remained normal in all types of diabetes, whereas a later marker, skeletal ALP, is frankly abnormal only in diabetic children. The most mature osteoblast marker, osteocalcin, is decreased in all types of diabetes irrespective of age.

Urinary excretion of deoxypyridinolin during treatment with pamidronate in post-menopausal osteoporosis

This longitudinal study evaluated bone turnover and the interrelationship between changes in bone biomarkers and habitual dietary calcium intake during pregnancy in a group of women ranging widely with regard to dietary calcium intake. Thirty-nine healthy pregnant and 30 nonpregnant women were studied. Calcium, phosphorus, 1α,25-dihydroxyvitamin D (1,25diHOD), bone alkaline phosphatase (bALP), carboxyterminal propeptides of type I procollagen (PICP) and carboxyterminal telopeptides of type I collagen (βCTX and ICTP) were measured in serum and calcium, and creatinine and aminoterminal telopeptide (NTX) were determined in urine. Serum calcium and phosphorus did not change but the urinary Ca/Creat ratio and 1,25diHOD increased throughout pregnancy (P < 0.001 and P < 0.0001, respectively). Serum b-ALP and PICP increased during the last two trimesters (P < 0.0001 and P < 0.001, respectively). All studied bone resorption markers increased compared to nonpregnant values throughout pregnancy. The highest increment was observed in the third trimester. The level of significance decreased as follows: βCTX > NTX >ICTP. Serum 1,25 diHOD versus calcium intake showed a positive and significant correlation (r = 0.51, P < 0.02). A negative correlation between the absolute change in βCTX, NTX, and b-ALP between the third and second trimester and calcium intake at the end of pregnancy was observed in pregnant women who did not cover adequately calcium intake requirements (r = −0.47, P < 0.03; r = −0.41, P < 0.05; and r = −0.43, P < 0.05, respectively). These results suggest that skeletal response to pregnancy may not be entirely independent of maternal calcium intake, especially in women with usually low calcium intake. In summary, not only hormonal changes in calcium metabolism that occur during pregnancy but also other considerations, such as low dietary calcium intake, may lead to an increment in the biological activity of the skeleton. Additional studies must be conducted to confirm our findings and to gain a better understanding of skeletal response to a low calcium intake during pregnancy.

Effects of infusion of parathyroid hormone and primary hyperparathyroidism on formation and breakdown of type I collagen

The influence of chronic and acute exposure to parathyroid hormone (PTH) on formation and breakdown of type I collagen, using two recently developed radioimmunoassays for serum PICP (the carboxyterminal propeptide of type I procollagen) and serum ICTP (the carboxyterminal telopeptide of type I collagen), have been evaluated. Fasting morning values were obtained from 18 women with primary hyperparathyroidism (HPT) and an equal number of age-matched, healthy controls. A 24-hour infusion of synthetic human parathyroid hormone (PTH 1-38) was performed in 14 healthy females. The patients with HPT had higher values for serum ICTP than the controls (6.0 +/- 3.0 and 4.1 +/- 2.1 micrograms/liter; P < 0.05), whereas the serum PICP concentrations were not different (170 +/- 72 and 151 +/- 65 micrograms/liter; n.s.). During infusion of PTH in healthy subjects, there was an increase of the serum ICTP concentrations (from 3.6 +/- 1.3 to 4.4 +/- 1.8 micrograms/liter; P < 0.001) whereas those of serum PICP decreased (from 185 +/- 78 to 118 +/- 42 micrograms/liter; P < or = 0.0001). The increase of serum ICTP during infusion of PTH was positively related to the increase of serum calcium and other indices of bone resorption, i.e., fasting urinary excretions of hydroxyproline and calcium. The decrease of serum PICP was also related to the changes of serum ICTP and hydroxyproline in urine, serum calcium, and alkaline phosphatase but not to osteocalcin, an established marker of osteoblastic activity. The findings support the fact that serum ICTP is a valuable method for evaluating bone resorption and is also easy to perform.(ABSTRACT TRUNCATED AT 250 WORDS)