Serum procollagen type 1 amino-terminal propeptide (P1NP) as an early predictor of the growth response to growth hormone treatment: Comparison of intrauterine growth retardation and idiopathic short stature

Bone Turnover Markers during Growth Hormone Therapy for Short Stature Children Born Small for Gestational Age

Growth hormone therapy (GHT) can improve growth velocity and final height, but can also accelerate the process of bone growth, which is related to structural bone modeling in both formation and resorption. This study evaluated the capacity of bone turnover markers to predict early growth response to one year of GHT in short stature children born small for gestational age (SGA). This study included 25 prepubertal children born SGA. We estimated P1NP (N-terminal procollagen type 1), CTX (C-terminal telopeptide of collagen type 1), P3NP (N-terminal procollagen type 3), NT-pro-CNP (amino-terminal C-type natriuretic peptide) and Ca-P metabolism using standard ECLIA (electrochemiluminescence), RIA (radioimmunoassay), and ELISA (enzyme-linked immunosorbent assay) methods. A statistically significant increase in bone resorption markers (CTX) was found at both 6 and 12 months. P1NP bone markers were increased at 6 months and after 12 months of therapy. The P3NP marker for collagen synthesis also increased after 12 months of therapy. We obtained significant increases in phosphorus levels at 6 and 12 months, and similar ALP (alkaline phosphatase) increases. We found a significant correlation between height (cm) and CTX after 6-12 months, as well as a P1NP/height (SD) correlation after 12 months. Calcium levels significantly correlated with height (SD) after 12 months. We found strong reactions of bone resorption and bone formation markers during growth hormone therapy, which may determine their selection as predictors of GHT outcome in children born SGA. However, the issue requires further research.

Bone Turnover Markers in Children: From Laboratory Challenges to Clinical Interpretation

Bone turnover markers (BTMs) have been developed many years ago to study, in combination with imaging techniques, bone remodeling in adults. In children and adolescents, bone metabolism differs from adults since it implies both growth and bone remodeling, suggesting an age- and gender-dependent BTM concentration. Therefore, specific studies have evaluated BTMs in not only physiological but also pathological conditions. However, in pediatrics, the use of BTMs in clinical practice is still limited due to these many children-related specificities. This review will discuss about physiological levels of BTMs as well as their modifications under pathological conditions in children and adolescents. A focus is also given on analytical and clinical challenges that restrain BTM usefulness in pediatrics.

Broad application prospects of bone turnover markers in pediatrics

BACKGROUND

Bone turnover markers (BTMs) have been studied for application in clinical medicine. However, BTMs in children are challenging, and few studies explore these BTMs in children. The application of BTMs is complicated mainly due to pre-analytical factors, variable reference intervals of age- and sex-related BTMs for adolescents and children in different regions and laboratories. Therefore, laboratory testing of BTMs is critical for understanding pediatric bone development and metabolism, which provides additional information about bone development and diseases.

METHODS

Literature search was conducted using the MeSH term "child" combined with the terms that bone turnover markers such as "osteocalcin," "Procollagen type I N-terminal propeptide," "procollagen type I C-terminal propeptide," "osteocalcin," "N-terminal cross-linked telopeptide," and "C-terminal cross-linked telopeptide," Several databases including Web of Science, Google Scholar, and PubMed were searched to obtain the relevant studies.

RESULTS

BTMs represent the combined effects of skeletal development, growth, and remodeling in children, which can be used in clinical pediatrics to assist in the diagnosis and prognosis of bone metabolic disorders.

CONCLUSION

BTMs are clearly helpful for diagnosis and monitoring of bone growth and development as well as bone metabolic disorders.

LCN2 is a new diagnostic biomarker and potential therapeutic target in idiopathic short stature

Idiopathic short stature (ISS) is the most common paediatric endocrine disease. However, the underlying pathology of ISS remains unclear. Currently, there are no effective diagnostic markers or therapeutic strategies available for ISS. In this study, we aimed to identify differential plasma protein expression and novel biomarkers in patients with ISS, and elucidate the biological functions of candidate proteins in ISS pathogenesis. Four specimen pairs from four ISS children and age‐/sex‐matched control individuals were subjected to proteomics analysis, and 340 samples of children with a mean age 9.73 ± 0.24 years were utilized to further verify the differentially expressed proteins by enzyme‐linked immunosorbent assay (ELISA). The receiver‐operating characteristic (ROC) curve and the area under the ROC curve (AUC) were plotted. A total of 2040 proteins were identified, of which 84 were differentially expressed. In vitro and in vivo experiments confirmed the biological functions of these candidate proteins. LCN2 overexpression in ISS was verified using ELISA. Meanwhile, LCN2 showed high sensitivity and specificity in discriminating children with ISS from those with growth hormone deficiency, precocious puberty and normal control individuals. The upregulated expression of LCN2 not only suppressed food intake but also impaired chondrocyte proliferation and bone growth in chondrocytes and rats. As a result, the rats presented a short‐stature phenotype. Subsequently, we found that bone growth inhibition recovered after LCN2 overexpression was stopped in immature rats. To our knowledge, this is the first study to report that LCN2 may be a significant target for ISS diagnosis and treatment.

Correlation between bone turnover and metabolic markers with age and gender: a cross-sectional study of hospital information system data

BACKGROUND

Bone turnover and metabolic indicators are related to age and gender. Age and gender should be matched in subjects in disease control research of bone turnover and metabolism, but strict matching of gender and age increases the difficulty and cost of the research. Therefore, the aim of this study was to solve it is necessary to strictly match age and gender in clinical research in bone metabolism.

METHODS

A cross-sectional study was conducted from the data were extracted from the HIS of ZhuJiang Hospital. Data relating to seven bone turnover and metabolic indicators from 1036 patients between January 2018 and October 2019 were analyzed.

RESULTS

P1NP, β-CTx and 25(OH)D were significant different in individuals younger than 20 years of age. ALP was significantly higher in those under 20 years of age and lower at age 20-39 compared with other age groups. The concentrations of Ca and P were different among the groups aged 0-19, 20-39, and 40-59 years of age groups but exhibited no difference above 60 years of age. PTH expression was not dependent on age. P1NP, β-CTx and PTH concentrations were not significantly different between the genders within the same age group. ALP was significantly different between genders within the age range 20-59 years. Ca and 25(OH)D were significantly different between the genders for those older than 60. Serum P was significantly different in the two genders for those aged 40-79. Patients received both alfacalcidol and calcium treatment differently from the others in P1NP, β-CTx, Serum Ca, P and ALP.

CONCLUSION

P1NP and β-CTx were highly correlated with age. If these two indictors require analysis in a case control study, the patients and controls should be strictly matched by age under 20 years. The demarcation point for ALP was 40 years of age. Ca and P were strongly recommended strict matching according to age in disease research. The difference in P1NP, β-CTx, 25(OH)D and ALP between genders depends on age differences. Medication history should be considered in bone turnover and metabolic clinical research.

Variation of bone acquisition during growth hormone treatment in children can be explained by proteomic biomarkers, bone formation markers, body composition and nutritional factors

OBJECTIVE

Growth hormone (GH) regulates both longitudinal growth and bone acquisition in children, and has profound metabolic effects. The aim was to investigate the association between proteomic biomarkers, body fat, nutrition and bone formation markers, and longitudinal growth in response to GH during the first year of treatment. The degree to which changes in these factors could explain variations in GH-dependent longitudinal growth and bone mineralization was also assessed.

METHODS

The individualized GH dose trial included 128 short prepubertal children with either normal (non-GH-deficient) or reduced levels of GH secretion (GH-deficient) (mean age ± SD, 8.6 ± 2.6 years; 90 boys), i.e., with a broad range of GH-secretion and GH-responsiveness, receiving GH treatment (mean 43 μg/kg/day). Blood samples were taken and dual-energy X-ray absorptiometry (DXA) measured at baseline and 1 year of treatment. Step-wise multiple regression models were constructed including three steps with different independent variables added at each step to explain the variance in outcome variables (height_SDS, bone mineral content (BMC) and bone mineral density (BMD). Independent variables included in Step I were previously identified proteomic markers related to GH treatment response, bone formation markers (intact PINP, bone-specific alkaline phosphatase and osteocalcin), variables at treatment start (GH dose mU/kg/day, GH maximum secretion, and difference between child's current and mid-parental height_SDS). Step II explored the added influence of body composition data (body mass index or DXA). Step III explored the added influence of serum nutritional markers and hormones.

RESULTS

Step I variables explained 71% of the variation in first year height_SDS gain, median (minimum-maximum) 0.8 (0.24-1.67); and the proportion explained rose to 73% following inclusion of step II variables and 75% following step III. Corresponding values for total body BMC were 58%, 78%, and 80%, respectively. Proportions fell by approximately 20% when BMC was adjusted for height; 33%, 57%, and 57% for steps I, II, and III, respectively. Corresponding values for total body BMD were 29%, 39%, and 45%, respectively.

CONCLUSION

For total BMC, as much as 80% of the variation during the first year of GH treatment could be explained by proteomic biomarkers, body fat, nutrition and bone formation markers, whereas for height-adjusted BMC 57% could be explained. The inclusion of information about either body composition (fat/lean mass) or nutritional markers contributed with approximately 20%. The variation in height_SDS gain could be explained to 75%. Hence, information of fat or nutrition markers was needed for explaining the variation in bone acquisition to the same magnitude as explaining the variation in height response.

Short-term changes in bone formation markers following growth hormone (GH) treatment in short prepubertal children with a broad range of GH secretion

OBJECTIVES

Growth hormone (GH) promotes longitudinal growth and bone modelling/remodelling. This study investigated the relationship between levels of bone formation markers and growth during GH treatment in prepubertal children with widely ranging GH secretion levels.

METHODS

The study group comprised 113 short prepubertal children (mean age ± SD, 9·37 ± 2·13 years; 99 boys) on GH treatment (33·0 ± 0·06 μg/kg/day) for 1 year. Blood samples were taken at baseline and 1 and 2 weeks, 1 and 3 months, and 1 year after treatment start. Intact amino-terminal propeptide of type I procollagen (PINP), bone-specific alkaline phosphatase (BALP) and osteocalcin were measured using an automated IDS-iSYS immunoassay system.

RESULTS

Intact amino-terminal propeptide of type I procollagen (PINP), BALP and osteocalcin, increased in the short-term during GH treatment. PINP after 1 week (P = 0·00077), and BALP and osteocalcin after 1 month (P < 0·0001 and P = 0·0043, respectively). PINP levels at 1 and 3 months correlated positively, and osteocalcin levels at 1 week and percentage change after 1 month correlated negatively, with first year growth response. No significant correlations were found between BALP and first year growth. Multiple regression analysis showed that bone marker levels together with auxological data and insulin-like growth factor binding protein-3 explained the variation in first year growth response to 36% at start, 32% after 2 weeks and 48% at 3 months.

CONCLUSION

Short-term increases in levels of the bone formation markers PINP, BALP and osteocalcin showed different temporal patterns, but all correlated with first year growth response during GH treatment. These markers may be a useful addition to existing prediction models for growth response.

Consumption of vitamin D-and calcium-fortified soft white cheese lowers the biochemical marker of bone resorption TRAP 5b in postmenopausal women at moderate risk of osteoporosis fracture

The prevention of increased bone remodeling in postmenopausal women at low 10-y risk of osteoporotic fractures essentially relies on reinforcement of environmental factors known to positively influence bone health, among which nutrition plays an important role. In institutionalized women in their mid-eighties, we previously found that consumption of fortified soft plain cheese increased vitamin D, calcium, and protein intakes, reduced bone resorption biochemical markers, particularly the serum bone specific acid phosphatase tartrate resistant acid phosphatase, isoform 5b (TRAP 5b) that reflects osteoclast activity, and stimulated the serum bone anabolic factor insulin-like growth factor-I (IGF-I). Whether these effects occur in much younger women was tested in a prospective control study. Seventy-one healthy postmenopausal women aged 56.6 ± 3.9 y (mean ± SD) with low spontaneous supply of both Ca and vitamin D were randomized to consume daily (treated, n = 36) or not (controls, n = 35) two servings (2 × 100 g) of skimmed-milk, soft plain cheese for 6 wk. The vitamin D and Ca-fortified dairy product provided daily: 661 kJ, 2.5 μg vitamin D, 400 mg calcium, and 13.8 g protein. At the end of the intervention, the decrease in TRAP 5b and the increase in IGF-I were greater in the treated than in the control group (P < 0.02). The changes in serum carboxy terminal crosslinked telopeptide of type I collagen did not differ significantly between the two groups. In conclusion, like in elderly women, consumption by healthy postmenopausal women of a vitamin D and calcium-fortified dairy product that also increases the protein intake, reduces the serum concentration of the bone resorption biomarker TRAP 5b. This response, combined with the increase in serum IGF-I, is compatible with a nutrition-induced reduction in postmenopausal bone loss rate.

Nutritional approach for inhibiting bone resorption in institutionalized elderly women with vitamin D insufficiency and high prevalence of fracture

BACKGROUND

Nutritional approach to the deterioration of bone integrity and increased fracture risk appears to be particularly appropriate in elderly women living in nursing homes.

OBJECTIVE

To investigate the beneficial effect of the consumption of soft plain cheese on bone resorption markers in institutionalized elderly women.

DESIGN

Prospective, randomized crossover controlled study.

SETTING

Six French nursing homes or other institutions for elderly.

PARTICIPANTS

Institutionalized women ≥ 65 years old with low vitamin D status and calcium intake below 700 mg/day.

INTERVENTION

Consumption of soft plain cheese made of semi-skimmed milk which was fortified by both vitamin D3 (+1.25 µg/100g) and milk extracted Ca, thus achieving a total Ca content of 151 mg/100g as compared to about 118 mg/100g for standard fresh cheese. Two servings were taken every day during the 6 weeks that preceded or followed a period of 6 weeks without soft plain cheese consumption.

MEASUREMENTS

The primary end point was the change in serum carboxy terminal cross-linked telopeptide of type I collagen (CTX) selected as a marker of bone resorption.

RESULTS

29 women aged 73-94 yr were selected, 21 of them with mean age 87.2±6.1 years remained compliant. The intervention increased calcium and protein intakes by 51% (904±228 vs. 599±122 mg/d) and 33 % (74.2±17.1 vs. 55.6±12.7 g/d, mean±SD), respectively. The dietary intervention was associated with a statistically significant increase in serum levels of both 25OHD and IGF-I, while those of [corrected] CTX and TRAP5b were significantly reduced. Compliance was 93,4 %. The daily consumption of two servings of soft plain cheese was well accepted in terms of tastiness and appetite suited portion size.

CONCLUSION

This randomized crossover controlled trial demonstrates that in elderly women living in nursing homes, the consumption of soft plain cheese increasing the supply of vitamin D, calcium and proteins, could reduce bone resorption and thereby reduce the risk of incidental fragility fractures in the long term.

Inhibition of markers of bone resorption by consumption of vitamin D and calcium-fortified soft plain cheese by institutionalised elderly women

Acceleration of bone remodelling increases the risk of fragility fractures. The objective of the present study was to explore in elderly women whether a vitamin D and Ca-fortified dairy product providing about 17-25 % of the recommended intakes in vitamin D, Ca and proteins would reduce secondary hyperparathyroidism and bone remodelling in a way that may attenuate age-related bone loss in the long term. Thirty-seven institutionalised women, aged 84.8 (sd 8.1) years, with low serum 25-hydroxyvitamin D (5.5 (sd 1.7) ng/ml) were enrolled into a multicentre open trial to consume during 1 month two servings of soft plain cheese made of semi-skimmed milk providing daily 686 kJ (164 kcal), 2.5 microg vitamin D, 302 mg Ca and 14.2 g proteins. The primary endpoint was the change in serum carboxy terminal cross-linked telopeptide of type I collagen (CTX), selected as a marker of bone resorption. Thirty-five subjects remained compliant. Mean serum changes were: 25-hydroyvitamin D, +14.5 % (P = 0.0051); parathyroid hormone (PTH), - 12.3 % (P = 0.0011); CTX, - 7.5 % (P = 0.01); tartrate-resistant acid phosphatase isoform 5b (TRAP 5b), - 9.9 % (P < 0.0001); albumin, +6.2 % (P < 0.0001); insulin-like growth factor-I (IGF-I),+16.9 % (P < 0.0001); osteocalcin, +8.3 % (P = 0.0166); amino-terminal propeptide of type 1 procollagen (P1NP),+19.3 % (P = 0.0031). The present open trial suggests that fortified soft plain cheese consumed by elderly women with vitamin D insufficiency can reduce bone resorption markers by positively influencing Ca and protein economy, as expressed by decreased PTH and increased IGF-I, respectively. The rise in the bone formation marker P1NP could be explained by a protein-mediated increase in IGF-I. Thus, such a dietary intervention might uncouple, at least transiently, bone resorption from bone formation and thereby attenuate age-related bone loss.

Inhibition of bone turnover by milk intake in postmenopausal women

Increased postmenopausal bone turnover leads to bone loss and fragility fracture risk. In the absence of osteoporosis, risk preventive measures, particularly those modifying nutritional lifestyle, are appropriate. We tested the hypothesis that milk supplementation affects bone turnover related to biochemical markers in a direction that, in the long term, may be expected to reduce postmenopausal bone loss. Thirty healthy postmenopausal women aged 59·3 (sd3·3) years were enrolled in a prospective crossover trial of 16 weeks. After a 4-week period of adaptation with diet providing 600 mg calcium plus 300 mg ingested as 250 ml semi-skimmed milk, participants were maintained during 6 weeks under the same 600 mg calcium diet and randomized to receive either 500 ml semi-skimmed milk, thus providing a total of 1200 mg calcium, or no milk supplement. In the next 6 weeks they were switched to the alternative regimen. At the end of the each period, i.e. after 4, 10 and 16 weeks, blood and urinary samples were collected. The changes in blood variables between the periods of 6 weeks without and with milk supplementation were: for parathyroid hormone, − 3·2 pg/ml (P = 0·0054); for crosslinked telopeptide of type I collagen, − 624 pg/ml (P < 0·0001); for propeptide of type I procollagen, − 5·5 ng/ml (P = 0·0092); for osteocalcin, − 2·8 ng/ml (P = 0·0014). In conclusion, a 6-week period of milk supplementation induced a decrease in several biochemical variables compatible with diminished bone turnover mediated by reduction in parathyroid hormone secretion. This nutritional approach to postmenopausal alteration in bone metabolism may be a valuable measure in the primary prevention of osteoporosis.

Idiopathic short stature: management and growth hormone treatment

In the management of ISS auxological, biochemical, psychosocial and ethical elements have to be considered. In boys with constitutional delay of growth and puberty androgens are effective in increasing height and sexual characteristics, but adult height is unchanged. GH therapy is efficacious in increasing height velocity and adult height, but the inter-individual variation is considerable. The effect on psychosocial status is uncertain. Factors affecting final height gain include GH dose, height deficit in comparison to midparental height, age and first year height velocity. In case of a low predicted adult height at the onset of puberty, addition of a GnRH analogue can be considered. Although GH therapy appears safe, long-term monitoring is recommended.

Recombinant human growth hormone for children born small for gestational age: meta-analysis confirms the consistent dose-effect relationship on catch-up growth

BACKGROUND

The optimal treatment regimen of recombinant human GH (r-hGH) for short children born small for gestational age (SGA) is still under discussion.

METHODS

A meta-analysis was performed of existing clinical trials that investigated the treatment of r-hGH in short children diagnosed SGA or with intrauterine growth retardation to determine the relationship between the daily r-hGH dose (placebo/no treatment; 0.033 mg/kg/day; 0.067 mg/kg/day) and the effect on growth [change in height-SD score (SDS) for chronological age]. A mathematical model describing the dose-response relationship was produced, and growth response (gain in height-SDS) to 2 yr of r-hGH 0.033 mg/kg/day [somatropin (rDNA origin) for injection; Serono] was estimated and compared with the response to other r-hGH formulations.

RESULTS

The relationship between r-hGH dose and 2-yr growth response was described by an equation. The equation yielded a mean difference in height- SDS gain of 0.48 (0.35) between r-hGH 0.033 and 0.067 mg/kg/day in favor of the higher dose. The height-SDS gain after 2 yr of Serono r-hGH formulation, 0.033 mg/kg/day was estimated as 1.2. Comparison of this estimate to the growth response to 2-yr treatment at 0.033 mg/kg/day of other r-hGH formulations (mean difference in height-SDS 0.05, lower limit of the 95% confidence interval=-0.15) confirmed that growth response to Serono r-hGH formulation 0.033 mg/kg/day is an inferred response estimated to be within the range of observed responses to a (non-Serono formulation) r-hGH dose of 0.033 mg/kg/day.

CONCLUSION

There is a clear dose-response relationship for r-hGH in the treatment of short children born SGA and the analysis confirmed that treatment with Serono r-hGH formulation 0.033 mg/kg/day should provide a meaningful therapeutic response.