Grażyna Rowicka

Biochemical markers of bone metabolism in children with cow's milk allergy

Introduction Patients with cows milk allergy (CMA) and following a cow milk protein-free diet for a long time are potentially at risk of developing bone abnormalities. To assess the balance between bone formation and resorption processes, we determined serum concentrations of osteocalcin (OC), bone alkaline phosphatase (BALP), C-terminal telopeptide of type I collagen (CTX), fetuin-A, osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) in children with CMA. Material and methods The study included 50 prepubertal children with diagnosed cows milk allergy, who were under systematic medical and nutritional care at the Institute of Mother and Child and 40 healthy counterparts as a control group. The concentrations of bone metabolism markers were determined by immunoenzymatic assays. Results The diets of all investigated children were correct in terms of phosphorus and magnesium contents but deficient in terms of calcium and vitamin D. Serum OC and CTX as well as fetuin-A concentrations were similar in both studied groups. The BALP activity was significantly (p < 0.05) higher in children with cows milk allergy than in the controls. Serum OPG concentration was comparable in both groups, but the RANKL level was higher (p < 0.05) in CMA children than in healthy ones. Hence, the ratio of OPG/RANKL was lower in children with CMA. Conclusions Our study demonstrates slight disturbances in the profile of bone metabolism markers in growing children with CMA. The increase in RANKL level and decrease in OPG/RANKL ratio may contribute to intensification of bone resorption in these patients.

Total Oxidant and Antioxidant Status in Prepubertal Children with Obesity

Aims Obesity is accompanied by the formation of oxygen free radicals, whose intensified activity without effective defense mechanisms can lead to oxidative stress and related complications. We evaluated the presence of oxidative stress in obese prepubertal children. Methods The study included 83 healthy children aged 2–10 years (62 with obesity and 21 nonobese controls). Total oxidant capacity (TOC), total antioxidant capacity (TAC), oxidized low-density lipoprotein (ox-LDL), lipid parameters, glucose, and C-reactive protein (CRP) were measured in serum. Oxidative stress index (OSI) was calculated. Results Serum TOC concentration was significantly higher (p < 0.05) and TAC concentration was lower (p < 0.05) in obese children. OSI was higher (p < 0.01) in obese subjects compared with controls. CRP levels were normal in all children, but median CRP value was higher (p < 0.01) and HDL cholesterol levels were lower (p < 0.05) in the obese group. We found a significant negative correlation between TAC and ox-LDL concentrations (r = −0.27, p < 0.05) in obese children. Furthermore, obesity duration was positively correlated with TOC level (r = 0.32, p < 0.05) in this group. Conclusions Obesity-related oxidative stress already occurs in prepubescence. Early obesity diagnosis and the necessary therapeutic activity implementation is a vital strategy for the prophylaxis of free radical damage and related multiorgan complications.

Comparison of body composition and adipokine levels between thin and normal-weight prepubertal children ☆

OBJECTIVE Thinness can have substantial consequences for child development and health. Adipokines, including leptin and adiponectin, play a significant role in the regulation of important metabolic functions. The aim of this study was to investigate associations between body composition and serum leptin and adiponectin levels in thin and normal-weight children. METHODS The authors examined 100 healthy prepubertal children, who were divided into two subgroups: thin (n=50) and normal-weight children (n=50). Body composition was assessed by dual-energy X-ray absorptiometry. Serum concentrations of adipokines were determined by immunoenzymatic assays. RESULTS Thin children had a similar body height but significantly lower (p<0.0001) body weight, body mass index, fat mass, lean mass, and bone mineral content compared with normal-weight children. Serum concentrations of leptin were about 2-fold lower (p<0.0001) in thin vs. normal-weight subjects. Serum levels of total adiponectin, adiponectin multimers, and soluble leptin receptor (sOB-R) were similar in both groups. The leptin/soluble leptin receptor ratio and leptin/adiponectin ratios were lower (p<0.0001) in thin vs. normal-weight children. In both groups of children, it was found that body composition parameters were positively related with leptin but not with adiponectin levels. Additionally, bone mineral content was positively related with body mass index, fat mass, lean mass, and leptin level in thin and normal-weight children. CONCLUSIONS Prepubertal thin children have disturbances in body composition and adipokine profile. Early recognition of thinness and determination of body composition parameters and adipokine levels can be useful in medical and nutritional care of thin children for the optimization of bone mineral accrual.

Body composition parameters and adipokines levels in relation to bone mineral density in patients with malignant bone tumors after treatment

Recent data support the concept that adipokines, which are secreted by fat cells, are important modulators of bone metabolism. The aim of this study was to assess the relationships between body composition parameters, adipokines (leptin, adiponectin) and bone mineral density (BMD) in patients with malignant bone tumors after anticancer therapy.

Oxidative and Antioxidative Status of Children with Celiac Disease Treated with a Gluten Free-Diet

Aims Oxidative stress is a factor involved in the pathogenesis of celiac disease (CD), possibly affecting the course of the disease and celiac-related complications. We assessed the intensity of oxidative processes and the efficiency of antioxidant defense in children with celiac disease. Methods. Group I (n = 32) consisted of children with CD treated with a gluten-free diet, and group II (n = 24) consisted of healthy children on a traditional diet. Antioxidative and oxidative status was assessed by measurement of serum total antioxidant capacity (TAC), total oxidant capacity (TOC), and oxidized low-density lipoprotein (ox-LDL) and on the basis of oxidative stress index (OSI). Results There were no significant differences in serum TAC, TOC, ox-LDL, and OSI between children with CD and healthy children. Cluster analysis showed that the group of children with CD is not homogeneous in terms of serum TAC and TOC levels. About 50% of these children had TAC levels < 1.3 mmol/L and TOC levels > 0.35 mmol/L. Conclusions Strict adherence to a gluten-free diet by children with CD seems to be important for maintaining oxidative-antioxidant balance. However, further research is needed to identify factors potentially responsible for increased oxidative stress in some children with celiac disease despite adherence to a gluten-free diet.

The Assessment of Bone Regulatory Pathways, Bone Turnover, and Bone Mineral Density in Vegetarian and Omnivorous Children

Vegetarian diets contain many beneficial properties as well as carry a risk of inadequate intakes of several nutrients important to bone health. The aim of the study was to evaluate serum levels of bone metabolism markers and to analyze the relationships between biochemical bone markers and anthropometric parameters in children on vegetarian and omnivorous diets. The study included 70 prepubertal children on a lacto-ovo-vegetarian diet and 60 omnivorous children. Body composition, bone mineral content (BMC), and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry. Biochemical markers—bone alkaline phosphatase (BALP), C-terminal telopeptide of type I collagen (CTX-I), osteoprotegerin (OPG), nuclear factor κB ligand (RANKL), sclerostin, and Dickkopf-related protein 1 (Dkk-1)—were measured using immunoenzymatic assays. In vegetarians, we observed a significantly higher level of BALP (p = 0.002) and CTX-I (p = 0.027), and slightly lower spine BMC (p = 0.067) and BMD (p = 0.060) than in omnivores. Concentrations of OPG, RANKL, sclerostin, and Dkk-1 were comparable in both groups of children. We found that CTX-I was positively correlated with BMC, total BMD, and lumbar spine BMD in vegetarians, but not in omnivores. A well-planned vegetarian diet with proper dairy and egg intake does not lead to significantly lower bone mass; however, children following a lacto-ovo-vegetarian diet had a higher rate of bone turnover and subtle changes in bone regulatory markers. CTX-I might be an important marker for the protection of vegetarians from bone abnormalities.

Anti-Inflammatory and Pro-Inflammatory Adipokine Profiles in Children on Vegetarian and Omnivorous Diets

Adipose tissue is a highly active endocrine organ that secrets many pro-inflammatory as well anti-inflammatory adipokines. The aim of the study was to assess serum adipokine profile in prepubertal vegetarian and omnivorous children. Sixty-two children on a vegetarian diet and fifty-five children on an omnivorous diet, aged 5 to 10 years, were studied. Dietary assessment was performed using a nutritional software program. Body composition was measured by dual-energy X-ray absorptiometry. Serum concentrations of adipokines: leptin, soluble leptin receptor (sOB-R), adiponectin (total and high molecular weight), resistin, visfatin, vaspin, and omentin were determined by immunoenzymatic assays. Both studied groups of children were comparable in terms of age, weight, height, body mass index, and body composition. Vegetarians had a lower (p = 0.017) leptin/sOB-R ratio and lower serum concentrations of resistin (p = 0.051), compared with omnivores. Average levels of other adipokines did not differ between both groups of children. However, we observed significantly higher ratios of anti-inflammatory to pro-inflammatory adipokines: adiponectin/leptin 0.70 (0.37–0.93) vs 0.39 (0.28–0.74), p = 0.005, and omentin/leptin 0.40 (0.23–0.83) vs. 0.33 (0.15–0.48), p = 0.011 in vegetarians compared with omnivores. A well-planned vegetarian diet might beneficially affect the adipokine profile and inflammatory status expressed by the ratios of anti-inflammatory to pro-inflammatory adipokines in prepubertal children.

Assessment of Biochemical Bone Turnover Markers and Bone Mineral Density in Thin and Normal-Weight Children

Objective There is scant research examining the prevalence of thinness in early childhood, despite its potential negative consequences for health and development across the life course. The objective of this study was to assess bone status through measurement of bone mineral density and biochemical bone turnover markers, with special attention paid to carboxylated (c-OC) as well as undercarboxylated (uc-OC) forms of osteocalcin, in the groups of thin and normal-weight children. Design The study included 80 healthy prepubertal children (median age 7.0 years), who were divided (according to Cole’s international cutoffs) into 2 subgroups: thin children (n = 40, body mass index [BMI] = 13.5 kg/m2) and normal-weight children (n = 40, BMI = 16.1 kg/m2). Bone mineral density (BMD) and bone mineral content (BMC) were assessed by dual-energy x-ray absorptiometry method. Serum concentrations of C-terminal telopeptide of collagen type I (CTX), total osteocalcin (OC), and c-OC, and uc-OC forms of osteocalcin were determined using enzyme-linked immunosorbent assays. Results In thin children, we observed higher levels of bone resorption marker CTX compared with normal-weight peers. Total osteocalcin concentrations were comparable in both groups of children; however, in thin children we observed higher median values of uc-OC (34.40 vs. 29.30 ng/mL, P < 0.05) and similar c-OC levels (25.65 vs. 28.80 ng/mL). The ratio of c-OC to uc-OC was significantly lower (P < 0.05) in thin than in normal-weight children. Total BMD and BMC were significantly decreased (P < 0.0001) in thin children compared with normal-weight peers (0.724 ± 0.092 vs. 0.815 ± 0.060 g/cm2 and 602.7 ± 159.2 vs. 818.2 ± 220.1 g, respectively). Conclusion Increased concentrations of CTX and uc-OC might lead to disturbances in bone turnover and a decrease in bone mineral density in thin children.

Response to Letter to the Editor: “Comment on “Serum Hepcidin and Soluble Transferrin Receptor in the Assessment of Iron Metabolism in Children on a Vegetarian Diet””

We read the comments on our article BSerum hepcidin and soluble transferrin receptor in the assessment of iron metabolism in children on a vegetarian diet^ written by Piotr Rzymski and Tomas Ganz with a great interest. First of all, we thank them very much for excellently reviewing our paper and presenting an interesting alternative point of view. In our paper, we suggested that inclusion of novel markers such as hepcidin and soluble transferrin receptor (sTfR) can be useful in precise assessment of iron metabolism. Due to the fact that iron deficiency in children is a global problem and that iron plays an important role in many metabolic processes, we decided to undertake this subject knowing that iron deficiency may concern both children following traditional as well as vegetarian diets. Some researchers claim that in vegetarians the intake of iron needs to be higher (up to 80%) to overcome the lower availability of iron from plant sources. Similar to Rzymski and Ganz, we also question this recommendation. On the basis of our results, we suggested in a classical manner that decreased serum hepcidin and elevated sTfR levels might be the reason for subclinical iron deficiency in the studied prepubertal vegetarian children. This is our hypothesis, and we intend to do a follow-up on our children in a few years to ascertain whether they have normal values of hematological and biochemical parameters related to iron metabolism. This research would be particularly important due to the fact that some of the children (especially girls) will be in pubertal period when the need for iron is increased. We thank the authors for presenting an alternative interpretation of lower hepcidin and higher sTfR which may reflect a clinically benign form of adaptation for more efficient iron absorption and utilization. It is a very interesting point of view, and we agree with the authors that this might be the case in vegetarians who consume high amounts of ascorbic acid in their diets. However, we are wondering if this compensation is not caused by subclinical iron deficiency. We know that in case of vegetarian diets, compensatory effect may exist. This situation concerns not only iron metabolism but also bone metabolism. In another one of our studies (not published yet), we observed higher serum level of carboxylated osteocalcin in vegetarian children compared with omnivorous children. Osteocalcin is the main noncollagenous protein, which reflects osteoblast activity and bone formation and which may exist in two forms: carboxylated osteocalcin and undercarboxylated osteocalcin. Fully carboxylated osteocalcin plays an active regulatory role in bone mineralization. Since in vegetarian diet intake of vitamin K is generally higher than in traditional diet, elevated level of carboxylated form of osteocalcin might be a compensatory effect of vegetarian diet on bone health.

Cord Blood Adiponectin and Visfatin Concentrations in relation to Oxidative Stress Markers in Neonates Exposed and Nonexposed In Utero to Tobacco Smoke

Aims. Maternal smoking is considered as a source of oxidative stress, which has been implicated to disrupted adipokines expression in adipose tissue. We examined the relationship between selected adipokines and markers of oxidative stress/antioxidant defence in the umbilical cord of neonates exposed and nonexposed in utero to tobacco smoke. Methods. Subjects including 85 healthy neonates (born to 41 smokers and 44 nonsmokers) were tested for adiponectin, visfatin, oxidized low density lipoprotein (ox-LDL), total oxidant capacity (TOC), and total antioxidant capacity (TAC). Results. Cord serum visfatin, ox-LDL, and TOC were significantly higher (p < 0.001) but adiponectin and TAC were lower (p < 0.001 and p < 0.05, resp.) in smoking group than in tobacco abstinents. In whole group of children (adjusted for smoking status, gender, and birth weight) adiponectin showed negative and visfatin positive correlations with ox-LDL. In the model estimated separately for smokers ox-LDL explained 36% of adiponectin and 35.5% of visfatin variance, while in the model of nonsmokers it explained 36.8% and 69.4%, respectively. Conclusion. Maternal smoking enhances oxidative status and depletes antioxidant potential in newborns. Lower level of adiponectin and higher visfatin concentration seem to be related with a less beneficial oxidative stress profile and higher level of lipid peroxidation in neonates exposed and nonexposed in utero to tobacco smoke.