serum concentrations of sclerostin and bone turnover markers in

Developmental Period Medicine, 2013, XVII, 3
246
© IMiD, Wydawnictwo Aluna
Jadwiga Ambroszkiewicz1, Grażyna Rowicka2, Magdalena Chełchowska1,
Joanna Gajewska1, Małgorzata Strucińska2, Teresa Laskowska-Klita1
SERUM CONCENTRATIONS OF SCLEROSTIN
AND BONE TURNOVER MARKERS IN CHILDREN
WITH COW`S MILK ALLERGY
STĘŻENIA SKLEROSTYNY I MARKERÓW OBROTU KOSTNEGO
W SUROWICY KRWI DZIECI Z ALERGIĄ
NA BIAŁKA MLEKA KROWIEGO
Screening Department
Department of Nutrition
Institute of Mother and Child, Warsaw, Poland
1
2
Abstract
The aim of this study was to assess concentrations of sclerostin and biochemical markers of bone
metabolism in children with cow’s milk allergy.
Material and methods: The study included 45 children (age range 2-6 years) with diagnosed cow`s
milk allergy, who were on a dairy-free diet and under systematic medical and dietary control at the
Institute of Mother and Child in Warsaw. The control group consisted of 40 healthy children (2-6 years),
who did not have any symptoms of cow`s milk allergy nor any diseases influencing bone metabolism.
Their diets included milk and dairy products. Dietary intake of macro- and micronutrients was
assessed based on 3-day records using the Dietetyk2® nutritional program. In the serum samples, we
measured concentrations of calcium, phosphate and total alkaline phosphatase by standard methods,
25-hydroxyvitamin D3 by chemiluminescence method and bone metabolism markers by immunoenzymatic methods. The Statistica (version 10.0) computer software was used for statistical analysis.
Results: The nutritional status of studied children based on BMI value was normal. In all patients, the
average daily value of dietary energy and percentage of energy from protein, fat and carbohydrates were
consistent with the recommended values. The intake of calcium in the diets of all children was deficient,
however, the intake of vitamin D was consistent with recommendations in the children with allergy, while
in the healthy children it was below the recommended values. Mean serum concentrations of calcium,
phosphate, alkaline phosphatase, 25-hydroxyvitamin D3, osteocalcin and C-terminal telopeptide of type
I collagen were similar in both studied groups. We observed significantly lower sclerostin levels in children
with cow`s milk allergy (0.295±0.116 ng/ml) than in the healthy children (0.353±0.126 ng/ml) (p<0.05).
The ratio of cytokines RANKL/OPG (receptor activator of nuclear factor κB ligand/osteoprotegerin) was
significantly higher in children with allergy compared with their healthy counterparts (p<0.05).
Conclusions: Basic laboratory parameters related to bone turnover in children with cow`s milk allergy,
who were under medical and nutritional care, were normal. Reduced levels of sclerostin and increased
ratio of cytokines RANKL/OPG may suggest disturbances in the balance between bone formation and
bone resorption in these patients. Further research is needed on bone metabolism in children with food
allergy, who due to the use an elimination diet may be at risk of developing abnormalities in the skeletal
system.
Key words: sclerostin, RANKL/OPG, bone formation and resorption markers, cow`s milk allergy
Streszczenie
Cel: Celem pracy była ocena stężenia sklerostyny oraz markerów obrotu kostnego u dzieci z alergią na
białka mleka krowiego.
Serum concentrations of sclerostin and bone turnover markers in children with cow`s milk allergy
247
Materiał i metody: Badaniami objęto 45 dzieci w wieku od 2 do 6 lat z alergią na białka mleka krowiego, pozostających na diecie bezmlecznej, będących pod opieką Instytutu Matki i Dziecka w Warszawie. Grupę porównawczą stanowiło 40 zdrowych dzieci (2-6 lat), u których wykluczono uczulenie
na białka mleka krowiego i nie stwierdzono chorób mogących mieć wpływ na metabolizm kostny.
Były to dzieci pozostające na diecie z udziałem mleka i jego przetworów. Do oceny sposobu żywienia
posłużono się analizą 3-dniowych zapisów jadłospisu z wykorzystaniem programu Dietetyk2®. W surowicy krwi wszystkich badanych dzieci oznaczano stężenie wapnia, fosforanów i fosfatazy alkalicznej
standardowymi metodami na analizatorze biochemicznym, 25-hydroksywitaminy D3 − metodą
chemiluminescencyjną oraz markerów metabolizmu kostnego – metodami immunoenzymatycznymi.
Analizę statystyczną uzyskanych wyników przeprowadzono z zastosowaniem programu komputerowego Statistica 10.0 PL.
Wyniki: Stan odżywienia badanych dzieci był prawidłowy. Średnia wartość energetyczna diet oraz procent energii pochodzącej z poszczególnych makroskładników w obu grupach dzieci były zgodne z zaleceniami. Średnia podaż wapnia w dietach dzieci była niedoborowa, natomiast witaminy D w dietach
dzieci z alergią na białka mleka krowiego zgodna, a w grupie dzieci zdrowych niższa w odniesieniu do
zaleceń. Stężenia wapnia, fosforanów, fosfatazy alkalicznej, 25-hydroksywitaminy D3 oraz osteokalcyny i C-końcowego telopeptydu kolagenu typu I w surowicy krwi były porównywalne w obu badanych
grupach. Stwierdzono istotnie niższe wartości sklerostyny w surowicy krwi dzieci z alergią w porównaniu z grupą kontrolną (0,295±0,116 ng/ml vs 0,353±0,126 ng/ml; p<0,05). Stosunek cytokin RANKL/OPG
(ligand aktywatora receptora jądrowego czynnika κB/osteoprotegeryna) był wyższy u dzieci z alergią
w porównaniu do dzieci zdrowych (p<0,05).
Wnioski: U dzieci z alergią na białka mleka krowiego będących pod ścisłą opieką medyczno-żywieniową
wartości podstawowych parametrów gospodarki wapniowo-fosforanowej są prawidłowe. Obniżone
poziomy sklerostyny oraz podwyższony stosunek cytokin RANKL/OPG świadczą o występowaniu u tych
pacjentów zaburzeń równowagi pomiędzy procesami tworzenia i resorpcji kości. Niezbędne są dalsze
badania nad metabolizmem kostnym u dzieci z alergią pokarmową, które ze względu na stosowanie
diety eliminacyjnej mogą być grupą ryzyka wystąpienia nieprawidłowości w układzie kostnym.
Słowa kluczowe: sklerostyna, RANKL/OPG, markery tworzenia i resorpcji kości, alergia na białka
mleka krowiego
DEV. PERIOD MED., 2013, XVII, 3, 246252
INTRODUCTION
Studies on bone metabolism have so far underestimated
the role of osteocytes, which are formed from osteoblasts
and are located in the mineralized bone matrix. Osteocytes
play an important role in the bone formation process,
receiving and transmitting mechanostatic signals. These
signals activate wingless-type signaling pathways (Wnt),
of which the most known is the β-catenin-dependent
pathway (Wnt/β-catenin) (1, 2). Activation of this pathway
is initiated by binding a Wnt glycoprotein to Frizzled family
of seven transmembrane-spanning receptors and LRP 5
or 6 (low-density lipoprotein receptor-related protein). As
a result of this binding, a series of reactions occur leading
to the stabilization of cytoplasmic β-catenin protein,
which binds with transcription factors after translocation
into the nucleus. Lack of a binding of the ligand with
a specific receptor results in the inactivation of the Wnt
pathway. This mechanism is universal for signaling in
each cell, and its proper functioning affects differentiation
and apoptosis. In bone metabolism, activation of the
Wnt pathway stimulates bone formation process by
increasing osteoblast differentiation and proliferation.
Regulation of Wnt signaling is dependent upon many
proteins, including sclerostin which is synthesized by
mature osteocytes. Sclerostin is a product of the SOST
gene, located on chromosome 17q12-21. It acts by binding
to receptors LRP5 and LRP6, preventing binding with
Wnt proteins, which results in inhibition of the bone
formation (3, 4, 5).
Data from studies on animal models as well as
observations on humans indicate significant participation
of sclerostin in the regulation of bone turnover. Increased
bone formation and higher bone mineral density (BMD)
were observed in mice with knockout SOST gene (6). In
humans, mutations in the gene encoding sclerostin cause
two genetically-determined diseases: osteosclerosis and
Van Buchem disease, characterized by increased bone
formation and high bone mass. Studies showed a correlation
between sclerostin and BMD in adult populations (6, 7).
Research on sclerostin in patients with osteoporosis is
of particular interest, but study results are inconclusive.
Both higher as well as reduced sclerostin concentrations
were observed in these patients (7, 8, 9).
The OPG/RANKL/RANK cytokine system, which
belongs to the tumor necrosis factor (TNFα) superfamily,
is also involved in the regulation of bone metabolism.
The key factors of this link are receptor activator
of nuclear factor ĸB (RANK) located on osteoclast
precursor cells and receptor activator of nuclear
factor ĸB ligand (RANKL) produced by osteoblasts.
248
Jadwiga Ambroszkiewicz i wsp.
Osteoblasts also synthesize osteoprotegerin (OPG), which
is a decoy receptor. RANKL binding to RANK triggers
a cascade of gene expression leading to differentiation
of preosteoclasts into mature cells and to activation
of the resorption process. Osteoprotegerin inhibits
bone resorption by blocking RANKL from binding
with receptor. Imbalance in the RANKL/OPG system
are associated with abnormalities in bone metabolism
leading to increased bone resorption, which may result
in a decrease in bone mass (10, 11).
In recent years, there has been a steady increase in the
prevalence of atopic diseases. The most common food
allergen responsible for allergies in younger children is
cow’s milk proteins. The treatment of choice for cow’s
milk allergy (CMA) is absolute avoidance of cow`s milk
antigens. In infants and young children it is necessary
to use substitute formulas. In most cases extensively
hydrolyzed cow`s milk-derived formulas can be safety
introduced, and these are efficient and clinically and
metabolically well tolerated. However, sometimes they
are not accepted by children, and therefore may lead to
deficiencies. Some children with CMA can be given soybased formulas. Nutritional deficiencies can adversely
affect bone metabolism, especially in a period of intense
growth and development (12, 13, 14). A few studies on
bone assessment in children with cow’s milk allergy
found both normal and reduced bone mineral density
and biochemical markers of bone metabolism (15, 16,
17, 18).
The aim of this study was to assess concentrations
of sclerostin, cytokines RANKL and OPG, and bone
turnover markers in children with CMA.
MATERIAL AND METHODS
The study included 45 children (30 girls, 15 boys)
aged 3-6 years (median 4.4 years) with cow’s milk allergy
recognized by generally accepted standards and confirmed
by open oral food challenge. We observed various symptoms
of allergy: 24 (53%) patients had symptoms of the respiratory
system, 23 (51%) digestive system, 4 (9%) central nervous
system, and 23 (51%) atopic dermatitis. Sixteen patients
(35%) had symptoms within one system of the body, while
29 (65%) within various systems. None of the children
were treated with glucocorticoids. Patients had been
on a dairy-free diet for at least a year, and were under
systematic medical and dietary control at the Institute of
Mother and Child in Warsaw. Patients with CMA used
an extensively hydrolyzed whey formula (n=17, 38%),
soy-based formula (n=18, 40%), extensively hydrolyzed
casein formula (n=5, 11%), gluten-free grain products
(n=2, 4.5%), and rice-based beverages (n=3, 6.5%).
The control group consisted of 40 healthy children
(23 girls, 17 boys) aged 3-6 years (median 4.6 years),
who did not have any symptoms of cow`s milk allergy
nor any diseases influencing bone metabolism. Their
diets included milk and dairy products.
The nutritional status of children was measured using
anthropometric data (their current weight and height) as
well as the relative body mass index (BMI). The results were
compared to data for a healthy population of children in
Warsaw (19). Dietary intake of macro- and micronutrients
was assessed based on 3-day records (including 1 weekend
day) using the Dietetyk2® nutritional program. We estimated
average energy values, percentage of energy intakes from
macronutrients (proteins, fats, carbohydrates), dietary
intake of selected minerals (calcium, phosphorus) and
vitamin D with reference to current dietary guidelines
for the Polish population (20).
For biochemical tests, venous blood samples was
taken in the morning hours. Concentrations of calcium,
phosphate and total alkaline phosphatase (ALP) were
measured in serum using standard laboratory methods.
25-hydroxyvitamin D3 concentrations were determined
by chemiluminescence method using a DiaSorin kit
(USA). The remaining serum was frozen at -20oC until
measurement of bone metabolism markers. Concentrations
of these markers were determined by immunoenzymatic
methods (ELISA). Serum concentrations of OC and CTX
were measured using N-Mid Osteocalcin and Serum
CrossLaps kits (IDS, UK), sclerostin − Human Sclerostin
kit from TecoMedical (Switzerland), OPG – kit from Quidel
(USA), and total sRANKL – kit from ImmunoDiagnostics
(Germany). The intra-assay CVs and inter-assay CVs of
these methods was less than 10%.
The study was conducted after obtaining approval from
the Bioethics Committee of the Institute of Mother and
Child and written consent from the children’s parents.
Statistical analysis of the obtained results was performed
using Statistica 10.0 PL software. Data are presented as
mean and standard deviation for normal or median and
range for non-normal distribution of variables. Student’s
t test, Mann-Whitney test, Pearson’s or Spearman’s rank
correlation coefficient were used. A level of p<0.05 was
considered statistically significant.
RESULTS
Children in both groups were of similar age and
showed no significant differences in height, weight, or
BMI (table I). The average daily value of dietary energy and
percentage of energy from protein, fat and carbohydrates
were consistent with the recommended values (table II).
In both groups of children, the percentage of energy from
protein was similar. In allergic children, the percentage
of energy from carbohydrates was higher (56.6%), and
lower from fats (30.0%) than in the control group (52.1%
and 33.6%, respectively). Daily intake of phosphorus
in both groups was consistent with the recommended
values, and calcium was lower by about 40% than dietary
recommendations for children aged 4-6 years. Vitamin
D intake in children with CMA was consistent with
recommended values, but in children on a traditional
diet it was significantly lower at approximately 54% of
the daily requirement.
Serum concentrations of biochemical bone metabolism
parameters in both groups of children are presented in
table III. We observed significantly lower (about 20%)
concentrations of sclerostin in children with CMA
compared with the control group (p <0.05). However, the
ratio of cytokines RANKL/OPG was significantly higher
in children with CMA than in healthy children (p<0.05).
Serum concentrations of sclerostin and bone turnover markers in children with cow`s milk allergy
249
Table I. Characteris!c of studied children.
Tabela I. Charakterystyka badanych dzieci.
n
Age (years)
Gender (F/M)
Body weight (kg)
Body height (cm)
BMI (kg/m2)
Children with CMA
45
4.4±1.0
30/15
16.7±2.9
106.3±8.7
14.7±1.4
Healthy children
40
4.6±1.6
23/17
17.2±4.3
107.6±11.3
14.8±1.2
Data are presented as mean values ±SD.
Table II. Average daily energy and nutrients intake in diets of the studied children.
Tabela II. Zawartość energii oraz wybranych składników odżywczych całodziennej racji pokarmowej badanych dzieci.
Energy (kcal/day)a
Energy from protein (% )a
Energy from fat (%)a
Energy from carbohydrates (%)a
Calcium (mg/day)b
Phosphorus (mg/day)a
Vitamin D (µg/day)b
a
Children with CMA
1305±283
13.5±2.7
30.0±6.2
56.6±7.5
435.8 (321-598)
702.9±113.1
5.2 (2.8-6.9)
Healthy children
1394±309
14.3±2.9
33.6±5.4
52.1±5.9
464.0 (311-631)
714.5±196.1
2.7 (1.5-3.9)
p
0.3413
0.2312
0.0181
0.0391
0.2226
0.2345
0.0009
Data are shown as mean ± SD for normal or bmedian and range (25-75%) for non-normal variables.
Table III. Serum concentra!ons of biochemical bone metabolism parameters in children with CMA and in healthy
children.
Tabela III. Stężenia biochemicznych parametrów metabolizmu kostnego w surowicy krwi dzieci z CMA oraz u dzieci
zdrowych.
Scleros!n (ng/mL)a
RANKL/OPGb
OC (ng/mL)b
CTX (ng/mL)a
ALP (U/L)a
25-OH D3 (ng/mL)a
Calcium (mmol/L)a
Phosphate (mmol/L)a
a
Children with CMA
0.295±0.116
0.36 (0.29-0.50)
62.9 (50.1-75.9)
1.428±0.524
228.1±48.1
27.1±9.2
2.43±0.11
1.57±0.14
Healthy children
0.353±0.126
0.28 (0.11-0.43)
60.2 (49.4-79.1)
1.433±0.498
224.3±41.3
26.4±9.6
2.46±0.09
1.58±0.16
p
0.0201
0.0463
0.5989
0.9660
0.7040
0.6344
0.4397
0.4160
Data shown as mean ±SD for normal or bmedian and range (25-75%) for non-normal variables.
Concentrations of OC, CTX, ALP, 25-hydroxyvitamin
D3, calcium, and phosphate were similar in both groups
of children.
We found positive correlations between OC and CTX
in the group of children with CMA (r=0.513, p<0.001)
and in the control group (r=0.448, p<0.01). Moreover, we
observed correlations between concentrations of phosphates
and CTX (r=0.354, p<0.05 for CMA, r=0.356, p<0.05
for controls), and between phosphates and sclerostin
(r=0.397, p<0.01 for CMA, r=0.341, p<0.05 for controls).
Concentrations of sclerostin correlated with calcium
intake in the studied group (r=0.327, p<0.05) and in the
controls (r=0.385, p<0.01). We also observed a statistically
significant correlation between body weight and the
sclerostin concentrations (r=0.310, p<0.05 in the studied
group, r=0.396, p<0.01 in the control group). We found
no correlation between concentration of sclerostin and
bone turnover markers.
DISCUSSION
The presented results, just as in our previous studies,
showed comparable concentrations of biochemical
parameters associated with calcium and phosphate
metabolism in children with cow’s milk allergy and in
healthy children (18). Our findings are partly consistent
with the data obtained by Hidvegi et al. (17), who observed
concentrations of osteocalcin in children with CMA
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Jadwiga Ambroszkiewicz i wsp.
similar to those in the control group, but higher alkaline
phosphatase, and reduced C-terminal telopeptide of
type I collagen. The nutritional status of our children
with CMA, assessed on the basis of anthropometric
parameters, was normal. Analysis of diet in children
with CMA showed similar concentrations of calcium
and phosphorus and higher vitamin D compared with
the control group.
There are no studies in the literature on bone
metabolism regulation parameters in children with
CMA. Also, there are no studies evaluating the RANKL/
RANK/OPG cytokines and sclerostin associated with the
Wnt signaling pathway in these patients. The increased
ratio of RANKL/OPG, which we observed in children
with CMA may indicate intensified resorption. Other
authors showed higher concentrations of RANKL and
decreased OPG in patients with rheumatic diseases and
with anorexia nervosa, which may in part explain the
increased resorption and decreased bone mass observed
in these patients (21, 22, 23).
Recently, intensive studies have been conducted to
assess serum sclerostin concentrations in adults, but
there are few articles on sclerostin levels in children. In
healthy adults, the authors observed significantly higher
concentrations of sclerostin in men than in women,
and a positive correlation between sclerostin and age,
BMI, and BMD (24, 25). They found no correlation
between serum sclerostin and markers of bone turnover
in young adults; however, in groups of the elderly they
found negative correlations between some of the bone
parameters (BALP, PINP – N-terminal propeptide of
type I procollagen). The researchers demonstrated lower
sclerostin concentrations in individuals with increased
physical activity and postmenopausal women undergoing
hormone replacement therapy (24, 26).
In the available literature, there are only two studies on
sclerostin levels in healthy children populations. Kirmani
et al. (27) found significantly higher serum concentrations
of sclerostin in boys than girls, and demonstrated that
concentrations of this protein depended on age and sex.
Maximum sclerostin concentrations were observed in
girls around the age of 10 years, and in boys around 14
years, and a decline occurred in later stages of puberty.
This is consistent with previous data on other markers
of bone metabolism (28, 29). In addition, the authors
found a positive correlation between sclerostin and
markers of bone turnover (PINP and CTX). However,
Fischer et al. (30) did not observe correlations between
sclerostin concentrations and age and sex in children
and adolescents. The authors found positive correlations
between concentrations of sclerostin and calcium as well
as markers of bone metabolism (BALP and TRACP5b
– tartrate-resistant acid phosphatase 5b). Differences in
the above-mentioned results may be due to the use of
different kits to determine sclerostin. It was found that
sclerostin levels determined by two commercially available
kits showed statistically significant differences (31). We
can compare our results in a group of healthy children
to study conducted by Fisher, because we used the same
assay kit to determine sclerostin. (30). In our study we
found no difference between the mean concentrations of
this protein in the subgroup of healthy boys (0.356±0.111
ng/ml) and girls (0.349±0.109 ng/ml). However, our data
pertain to a narrow age range, 3-6 years, and a small
group of children. We found no significant correlation
between sclerostin and markers of bone turnover (OC,
ALP, CTX). Data on negative correlations of sclerostin
and markers of bone turnover in the elderly and positive
correlations in children may indicate a difference in bone
metabolism during development and adulthood.
We found significantly lower mean sclerostin levels
in the group of children with CMA compared with
healthy children. We did not observe differences in
sclerostin concentrations between the subgroups of boys
(0.316±0.128 ng/ml) and girls (0.283±0.072 ng/ml) with
CMA. Furthermore, we found positive correlations between
sclerostin concentrations and the serum concentrations
of phosphate, supply of calcium in the diet, and body
weight. We did not observe correlations between levels
of sclerostin and bone metabolism markers.
There are no studies in the literature evaluating sclerostin
in children with cow`s milk allergy or children with other
diseases. The researchers identified lower concentrations
of sclerostin in adult patients with chronic infections
and in patients treated with glucocorticoids (32, 33).
Significantly lower concentrations of this protein were
observed in adults with increased physical activity (9,
26). We did not assess intensity of physical activity in our
studied children. The authors of some studies suggest an
effect of estrogen on lowering sclerostin concentrations
(34). Approximately 40% of the studied children with
CMA consumed soy beverages that contain isoflavones
(compounds with a chemical structure similar to estrogen),
which may affect the stimulation of bone formation.
However, in the subgroups of children using and not
using soy products, we found no difference in sclerostin
concentrations (0.286±0.113 ng/ml vs 0.296±0.123 ng/ml,
respectively).
Although sclerostin has been studied for many years,
the exact mechanism of its activity is unknown. In in
vivo studies, authors found that sclerostin synthesis
depends on the mineralization process. No sclerostin
expression was observed in newly created osteocytes
(with unmineralized osteoid), but it was found shortly
after the first mineralization (35). It is possible that lower
concentrations of this protein in the studied children
with CMA should be explained by disorders of the
mineralization process. Other authors suggest that the
bone formation process may not be directly dependent
on sclerostin, but associated with bone morphogenetic
proteins (BMP) (36). The study by van Bezooijen et
al. (37) demonstrated that while sclerostin is seen as
an inhibitor of bone formation, it does not inhibit the
activity of ALP, one of the markers of bone formation.
We found no correlation between concentrations of
sclerostin and markers of bone formation, similarly to
Modder et al. (24) and Amrein et al. (25). According to
recent reports, sclerostin may also affect the functions of
osteoclasts and their activation in a RANKL-dependent
manner, which means that it is involved in the regulation
of osteoblastogenesis as well as osteoclastogenesis (38). The
increased ratio of RANKL/OPG we observed in children
Serum concentrations of sclerostin and bone turnover markers in children with cow`s milk allergy
with CMA may indicate intensified resorption. This was
confirmed in studies by Infante et al. (15), Jensen et al.
(16), and Hidvegi et al. (17), who documented reduced
bone mineral density in children with allergy.
In summary, this is the first report on biochemical markers
associated with bone metabolism regulation, including
sclerostin and cytokines OPG and RANKL in children
with cow’s milk allergy. Our results indicate that despite
normal concentrations of bone turnover markers, there are
abnormalities in the balance between bone formation and
resorption processes in these patients. This is supported by
a reduction in sclerostin concentrations associated with
regulation by the Wnt pathway, but also elevated concentrations
of RANKL in relation to OPG. Further research is needed
on bone metabolism in children with food allergy, who due
to the use of an elimination diet may be at risk of developing
abnormalities in the skeletal system.
REFERENCES
1. Kular J., Tickner J., Chim S.M., Xu J.: An overview of the
regulation of bone remodeling at the cellular level. Clin.
Biochem. 2012, 45(12), 863-873.
2. Sims N.A., Walsh N.C.: Intercellular cross-talk among
bone cells: New factors and pathways. Curr. Osteoporos.
Rep. 2012, 10(2), 109-117.
3. Moester M.J.C., Papapoulos S.E., Lowik C.W., van Bezooijen R.L.:
Sclerostin: Current knowledge and future perspectives.
Calcif. Tissue Int. 2010, 87(2), 99-107.
4. Devarajan-Ketha H., Craig T.A., Madden B.J., Robert-Bergen H.,
Kumar R.: The sclerostin-bone protein interactome. Biochem.
Biophys. Res. Commun. 2012, 417(2), 830-835.
5. Silverman S.L.: Sclerostin. J. Osteoporos. 2010, doi:
10.4061/2010/941419.
6. Li X., Ominsky M.S., Niu Q.T., Sun N., Daugherty B., D`Agostin D.,
Kurahara C., Gao J., Cao J., Gong J., Asuncion F., Barrero M.,
Warmington K., Dwyer D., Stolina M., Morony S., Sarosi I.,
Kostenuik P.J., Lacey D.L., Simonet W.S., Ke H.Z., Paszty C.:
Targeted deletion of the sclerostin gene in mice results
in increased bone formation and bone strength. J. Bone
Miner. Res. 2008, 23(6), 860-869.
7. Garnero P., Sornay-Rendu E., Munoz F., Borel O., Chapurlat R.D.:
Association of serum sclerostin with bone mineral density,
bone turnover, steroid and parathyroid hormones, and
fracture risk in postmenopausal women: the OFELY study.
Osteoporos. Int. 2013, 24(2), 489-494.
8. Szulc P., Bertholon C., Borel O., Marchand F., Chapurlat R.:
Lower fracture risk in older men with higher sclerostin
concentration – A prospective analysis from the MINOS
study. J. Bone Miner. Res. 2013, 28(4), 855-864.
9. Ardawi M.S., Rouzi A.A., Qari M.H.: Physical activity in
relation to serum sclerostin, insulin-like growth factor-1,
and bone turnover markers in healthy premenopausal
women: a cross-sectional and a longitudinal study. J. Clin.
Endocrinol. Metab. 2012, 97(10), 3691-3699.
10. Boyce B.F., Lianping X.: Functions of RANKL/RANK/
OPG in bone modeling and remodeling. Arch. Biochem.
Biophys. 2008, 473, 139-146.
11. Wagner D., Fahrleitner-Pammer A.: Levels of osteoproteregin
(OPG) and receptor activator for nuclear factor kappa B
ligand (RANKL) in serum: are they of any help? Wien.
Med. Wochenschr. 2010, 160(17-18), 452-457.
251
12. Kneepkens C.M.F., Meijer Y.: Clinical practice. Diagnosis
and treatment of cow`s milk allergy. Eur. J. Pediatr. 2009,
168, 891-896.
13. Vieira M.C., Morais M.B., Spolidoro J.V., Toporovski M.S.,
Cardoso A.L., Araujo G.T., Nudelman V., Fonseca M.C.:
A survey on clinical presentation and nutritional status of
infants with suspected cow`s milk allergy. BMC Pediatr.
2010, 10, 25.
14. De Greef E., Hauser B., Devreker T., Veereman-Wauters G.,
Vandenplas Y.: Diagnosis and management of cow`s milk
protein allergy in infants. World J. Pediatr. 2012, 8(1),
19-24.
15. Infante D., Tormo R.: Risk of inadequate bone mineralization
in diseases involving long-term suppression of dairy products.
J. Pediatr. Gastroenterol. Nutr. 2000, 30(3), 310-313.
16. Jensen V.B., Jorgensen I.M., Rasmussen K.B., Molgaard C.,
Prahl P.: Bone mineral status in children with cow milk
allergy. Pediatr. Allergy Immunol. 2004, 15, 562-565.
17. Hidvegi E., Arato A., Cserhati E., Horvath C., Szabo A.,
Szabo A.: Slight decrease in bone mineralization in cow
milk-sensitive children. JPGN 2003, 36, 44-49.
18. Rowicka G., Ambroszkiewicz J., Strucińska M., Dyląg H.,
Gołębiowska-Wawrzyniak M.: The evaluation of selected
parameters of calcium and phosphorus metabolism in
children with cow`s milk allergy. Med. Wieku Rozwoj.
2012, 16(2), 109-116.
19. Palczewska I., Niedźwiecka A.: Somatic development
indices in children and youth of Warsaw. Med. Wieku
Rozwoj. 2001, 5(2 Suppl), 17-118.
20. Jarosz M., Bułhak-Jachymczyk B.: Normy Żywienia Człowieka.
Podstawy prewencji otyłości i chorób zależnych. PZWL,
Warszawa 2008.
21. Xu S., Wang Y., Lu J., Xu J.: Osteoprotegerin and RANKL
in the pathogenesis of rheumatoid arthritis-induced
osteoporosis. Rheumatol. Int. 2012, 32(11), 3397-3403.
22. Munoz-Calvo M.T., Barrios V., Garcia de Alvaro M.T.,
Lefort M., Mendez-Davila C., Argente J., de la Piedra C.:
Maintained malnutrition produces a progressive decrease
in (OPG)/RANKL ratio and leptin levels in patients with
anorexia nervosa. Scand. J. Clin. Lab. 2007, 67(4), 387393.
23. Ostrowska Z., Ziora K., Oświęcimska J., Świętochowska E.,
Szapska B., Wołkowska-Pokrywa K., Dyduch A.: RANKL/
RANK/OPG system and bone status in females with anorexia
nervosa. Bone 2012, 50(1), 156-160.
24. Modder U.I., Hoey K.A., Amin S., McCready L.K., Achenbach S.J.,
Riggs B.L., Melton L.J., Khosla S.: Relation of age, gender,
and bone mass to circulating sclerostin levels in women
and men. J. Bone Miner. Res. 2011, 26(2), 373-379.
25. Amrein K., Amrein S., Drexler C., Dimai H.P., Dobnig H.,
Pfeifer K., Tomaschitz A., Pieber T.R., Fahrleitner-Pammer A.:
Sclerostin and its association with physical activity, age,
gender, body composition, and bone mineral content in
healthy adults. J. Clin. Endocrinol. Metab. 2012, 97(1),
148-154.
26. Czarkowska-Pączek B., Wesołowska K., Przybylski J.: Wysiłek
fizyczny w profilaktyce osteoporozy. Przegl. Lek. 2011,
68(2), 103-106.
27. Kirmani S., Amin S., McCready L.K., Atkinson E.J., Melton
L.J., Muller R., Khosla S.: Sclerostin levels during growth
in children. Osteoporos. Int. 2012, 23(3), 1123-1130.
252
Jadwiga Ambroszkiewicz i wsp.
28. Rauchenzauner M., Schmid A., Heinz-Erian P., Kapelari K.,
Falkensammer G., Griesmacher A., Finkenstedt G., Hogler W.:
Sex- and age specific reference curves for serum markers
of bone turnover in healthy children from 2 months to 18
years. J. Clin. Endocrinol. Metab. 2007, 92, 443-449.
29. Jurimae J.: Interpretation and application of bone turnover
markers in children and adolescents. Curr. Opin. Pediatr.
2010, 22(4), 494-500.
30. Fischer D.C., Mischek A., Wolf S., Rahn A., Salweski B., Kundt G.,
Haffner D.: Paediatric reference values for the C-terminal
fragment of fibroblast-growth factor-23, sclerostin, bonespecific alkaline phosphatase and isoform 5b of tartrateresistant acid phosphatase. Ann. Clin. Biochem. 2012,
49(Pt 6), 546-553.
31. McNulty M., Singh R.J., Li X., Bergstralh E.J., Kumar R.:
Determination of serum and plasma sclerostin concentrations
by enzyme-linked immunoassays. J. Clin. Endocrinol.
Metab. 2011, 96(7), 1159-1162.
32. Saad C.G., Ribeiro A.C., Moraes J.C., Takayama L., Goncalves C.R.,
Rodrigues M.B., Oliveira R.M., Silva C.A., Bonfa E., Pereira R.M.:
Low sclerostin levels: a predictive marker of persistent
inflammation in ankylosing spondylitis during anti-tumor
necrosis factor therapy? Arthritis Res. Ther. 2012, 14(5),
R216 [Epub ahead of print].
33. Brabnikova Maresova K., Pavelka K., Stepan J.: Acute effect of
glucocorticoids on serum markers of osteoclasts, osteoblasts,
and osteocytes. Calcif. Tissue Int. 2013, 92(4), 354-361.
34. Van Lierop A.H., van der Eeden A.W., Hamdy N.A.,
Hermus A.R., den Heijer M., Papapoulos S.E.: Circulating
sclerostin levels are decreased in patients with endogenous
hypercortisolism and increase after treatment. J. Clin.
Endocrinol. Metab. 2012, 97(10), 1953-1957.
35. Poole K.E., Bezooijen R.L., Loveridge N., Hamersma H.,
Papapoulos S.E., Lowik C.W., Reeve J.: Sclerostin is a delayed
secreted product of osteocytes that inhibits bone formation.
FASEB J. 2005, 19, 1842-1844.
36. Kamiya N., Ye L., Kobayashi T., Mochida Y., Yamauchi M.,
Kronenberg H.M., Feng J.Q., Mishina Y.: BMP signaling
negatively regulates bone mass through sclerostin by
inhibiting the canonical Wnt pathway. Development 2008,
135, 3801-3811.
37. Van Bezooijen R.L., Roelen B.A., Visser A., van der Wee-Pals L.,
de Witt E., Karperien M., Hamersma H., Papapoulos S.E.,
Dijke P., Lowik C.W.: Sclerostin is an osteocyte-expressed
negative regulator of bone formation, but not a classical
BMP antagonist. J. Exp. Med. 2004, 199(6), 805-814.
38. Wijenayaka A.R., Kogawa M., Lim H.P., Bonewald L.F.,
Findlay D.M., Atkins G.J.: Sclerostin stimulates osteocyte
support of osteoclast activity by a RANKL-dependent
pathway. PLoS One 2011, 6(10), e25900 [Epub ahead of
print].
Author’s contributions/Wkład Autorów
According to the order of the Authorship/Według kolejności
Conflicts of interest/Konflikt interesu
The Authors declare no conflict of interest.
Autorzy pracy nie zgłaszają konfliktu interesów.
Received/Nadesłano: 23.04.2013 r.
Accepted/Zaakceptowano: 28.05.2013 r.
Published online/Dostępne online
Address for correspondence:
Jadwiga Ambroszkiewicz
Screening Department
Institute of Mother and Child
Kasprzaka 17a, 01-211 Warsaw
tel./fax: (48 22) 3277260
e-mail: [email protected]