Biochemical measurements regarding mineral-vitamins status and bone metabolism markers in CF and control children are shown in Tab. 2. Mean serum calcium and phosphate levels were within normal range in both studied groups, but the concentration of 25-hydroxyvitamin D was lower in patients with CF compared to control children (p<0.05). <a href="http://www.selleckchem.com/products/obeticholic-acid.html
">Obeticholic Acid solubility dmso Plasma A and E vitamin levels were significantly (p<0.01 and p<0.05, respectively) lower in children with CF than in the healthy ones but stayed within the reference range. CF children, compared to controls, had significantly (p<0.01) lower osteocalcin level and similar CTX and TRACP5b concentrations. The serum level of OPG was significantly (p<0.05) lower and RANKL nearly 2-fold higher in patients with CF than in the healthy ones. Hence, the ratio of OPG to RANKL was about 2-fold lower in children with <a href="http://en.wikipedia.org/wiki/FARP1
">FARP1 CF compared to healthy peers (p<0.01). We observed significant negative correlation between serum concentrations of TRACP5b and OPG (r=-0.3603, p<0.05) in CF group and in healthy children (r=-0.3866, p<0.05). Additionally, we showed significant positive relation between OC and CTX (r=0.4924, p<0.01) in control group. So far, data regarding biochemical bone metabolism markers in pediatric population are limited, sometimes conflicting and until recently not fully explained [19, 20, 21, 22?and?23]. We found decreased concentration of bone formation marker (osteocalcin) in children with CF and comparable to controls levels of bone resorption markers (CTX and TRACP5b). This condition results in uncoupling of balance between bone formation and resorption processes and are unfavourable for bone development in these patients. Baroncelli et al.  in prepubertal CF children showed similar levels of bone formation and elevated bone resorption markers compared to controls. Other researchers observed similar or reduced values of OC and higher levels of bone alkaline phosphatase in CF patients <a href="http://www.selleckchem.com/products/Adriamycin.html
">selleck screening library [8, 20, 21?and?25]. Regarding bone resorption markers, similar levels of deoxypyridinoline and hydroxyproline or elevated levels of ICTP (carboxyterminal telopeptide of type I collagen) and NTX (N-terminal cross-linking telopeptide of type I collagen) in CF children compared to the healthy controls have been reported [19, 20?and?22]. The differences in the above results are probably due to the different nutritional status, lung disease severity of studied patients, as well as blood sample collection and problems with interpretation of bone marker results in children. In our study, only a few significant correlations between bone metabolism markers were detected. We observed weak negative correlation between serum concentrations of TRACP5b and OPG in both groups of children and positive correlation between OC and CTX in controls. Other correlations were not statistically significant, as bone metabolism markers reflect different biological processes during skeletal growth.