Adiponectin, adipocyte fatty acid binding protein, and epidermal fatty acid binding protein: proteins newly identified in human breast milk.
Although the substances responsible for the effects of breast milk have not been identified, leptin, an adipose tissue-derived cytokine that reflects the total amount of body fat and is a key player in the regulation of the nutritional status of the organism, is present in human colostrum and full breast milk (7). We investigated proteins present in human breast milk that are produced by adipose tissue and are related to lipid metabolism, adiponectin, adipocyte fatty acid binding protein (AFABP), and epidermal fatty acid binding protein (EFABP) (8-23).
Materials and Methods
The study included breastfeeding mothers who gave birth to a single healthy newborn at the Department of Neonatology, University Hospital Motol, Prague. Exclusion criteria were complications during delivery and/or the perinatal period requiring intensive care for the mother or newborn.
We collected breast milk samples 48 h after the beginning of lactation from 59 mothers by manual expression of 5 mL breast milk into tubes containing EDTA and protease inhibitor (aprotinin). The samples were collected after the end of the first morning breastfeeding (after 7:00 am) from the same breast used for breastfeeding the newborn and immediately frozen at -20[degrees]C. All participants gave written informed consent. The study was performed according to conditions of the Helsinki declaration and approved by the hospital ethics committee.
We obtained additional data from questionnaires and medical records. Maternal data included age, height, weight before pregnancy and at the time of delivery, weight gain during pregnancy, the number of previous pregnancies and deliveries, and complications of pregnancy. We calculated the body mass index (BMI) as (kg/[m.sup.2]). Data on newborns included sex, gestational age, body weight, and length at delivery. We counted the percentiles and SD score (SDS) of body weight according to gestational age and the ponderal index of newborns, defined as birth weight divided by cubic birth length (kg/[m.sup.3]).
Mean (SE) age of mothers was 28.9 (0.6) years, mean BMI before pregnancy was 21.4 (0.4) kg/[m.sup.2] and at the time of delivery 26.8 (0.4) kg/[m.sup.2]. Mean gestational age of newborns was 39.2 (0.2) weeks, mean SDS of birth weight was 0.08 (0.12) and mean body length 50.1 (0.3) cm. Thirty-two mothers delivered girls and 27 mothers delivered boys. Two mothers had a history of GDM, 1 with hypertension. Eleven newborns were delivered by caesarian section. Five children developed benign neonatal icterus, treated by phototherapy. Two boys were hypotrophic (below the 5th percentile of body weight for gestational age) and 1 boy was hypertrophic (above the 95th percentile). Eight newborns (2 boys and 6 girls) were delivered preterm (at 265 days or less), but all of them had adequate body weight (above the 5th percentile).
Samples. Whole breast milk samples were stored frozen until analysis. We assayed adiponectin in whole milk and leptin, AFABP, and EFABP in skim milk. Samples were thawed at 4-6[degrees]C overnight and centrifuged at 25008 at 4[degrees]C for 20 min to separate the fat milk. We removed the fat layer with a spatula and used the liquid for assays. The centrifugation step was repeated for turbid samples. We used the BCA (BCA-1, Sigma) method to measure total protein concentrations in skim breast milk samples.
Assays. We performed all determinations of adiponectin, leptin, and AFABP with commercially available ELISA kits (Biovendor-Laboratory Medicine).
Adiponectin assay. The adiponectin ELISA uses specific goat polyclonal antihuman adiponectin antibody coated in microtiter wells and native adiponectin prepared from human serum as a calibrator and biotin-labeled specific goat polyclonal antibody with streptavidin-HRP for detection. The antibody was raised against whole adiponectin (aa 15-244) and reacts with the whole molecule, including the globular domain (aa 104-244). Whole breast milk samples were diluted 3 times with a dilution buffer and assayed according to the manufacturer's instructions. The detection range of the assay was 1.0-50.0 [micro]g/L. Intraassay CVs were 3.8% for samples with low concentrations of protein (11.8 [micro]g/L) and 5.4% for high concentrations (22.2 [micro]g/L), and interassay CVs were 5.1% and 7.6%,respectively. The limit of detection reported by the manufacturer is 0.5 [micro]g/L.
To validate the assay, we used 2 whole breast milk samples with baseline adiponectin concentrations of 8.1 and 9.4 [micro]g/L enriched with various amounts of adiponectin calibrator to increase the original adiponectin concentration by +2.0 and +5.0 [micro]g/L. We obtained a mean recovery of 91.6%. Moreover, by diluting the samples 3-, 6-, 9-, and 12-fold, we tested whole breast milk samples from another 2 women with baseline adiponectin concentrations of 22.6 and 21.4 [micro]g/L. The mean recovery after dilution was 111.2%. To perform the correlation analysis, we ran the assay on 6 samples each of whole and skim breast milk.
Leptin assay. We measured leptin concentrations by ELISA as previously described (24). To improve the lower limit of detection, we modified the manufacturer's protocol. Skim milk samples were diluted 1:1 with dilution buffer; the range of calibrators was 0.2-10.0 [micro]g/L, and the incubation time of calibrators and samples in plate was 2 h. Intraassay CVs were 7.6% for samples with low protein concentrations (0.43 [micro]g/L) and 6.4% for high concentrations (1.03 [micro]g/L), and interassay CVs were 9.1% and 8.4%,respectively. The limit of detection reported by the manufacturer is 0.05 [micro]g/L.
AFABP assay. The AFABP ELISA (25) uses specific goat polyclonal antihuman AFABP antibody coated in microtiter wells, recombinant AFABP as a calibrator, and biotinlabeled specific rabbit polyclonal antibody used with streptavidin-HRP for detection.
Skim milk samples were diluted 5 times with dilution buffer and assayed according to the procedure recommended by the manufacturer. Assay results were 0.5-20.0 [micro]g/L, with an intraassay CV of 4.6% for a sample with low concentration of protein (4.5 [micro]g/L) and 3.9% for a sample with high concentration of protein (36.6 [micro]g/L). The interassay CVs were 6.6% and 5.1%, respectively. The limit of detection reported by the manufacturer is 0.1 [micro]g/L. The assay has no detectable cross-reactivity to human EFABP, HFABP, IFABP, LFABP, leptin, leptin receptor, adiponectin, resistin, RELM-(3 at 100.0 [micro]g/L, or IL-6 at 2.0 [micro]g/L.
To validate the assay, 2 skim breast milk samples with the baseline AFABP concentrations of 8.4 and 6.5 [micro]g/L were enriched with various amounts of AFABP calibrator to increase the AFABP concentrations by +2.0 and +5.0 [micro]g/L. The mean recovery was 92.7%. In addition, we tested skim breast milk samples from another 2 mothers with baseline AFABP concentrations of 11.1 and 15.1 [micro]g/L after the samples were diluted 5-, 10-, 15-, and 20-fold. The mean recovery for the diluted samples was 115.0%.
EFABP assay. We established the first immunoassay intended for quantitative measurement of EFABP and evaluated it for skim breast milk samples. We used specific sheep polyclonal antihuman EFABP antibody (Biovendor) coated in microtiter wells (Corning Costar, High Binding type): 100 [micro]L/well, 4 [micro]g/L in 0.1 mol/L carbonate buffer (pH 9.0) overnight at 4[degrees]C. The plate was washed once with TBS-Tw [0.05 mol/L Tris-HCI; 0.15 mol/L NaCI; pH = 7.2; 0.05% (w/v) Tween 20] on the washer Columbus (Tecan). Nonspecific biding sites were blocked with 250 [micro]L/we111%BSA (w/v) in TBS-Tw for 30-min at 25[degrees]C. After aspiration, diluted samples [50 [micro]L of skim breast milk sample diluted with 200 [micro]L of 5% BSA (w/v) in TBS-Tw] were pipetted in duplicates at 100 [micro]L/well. The plate was incubated for 1 h at 25[degrees]C. After 3 washes with TBS-Tw, 100 [micro]L/well of biotin-labeled specific rabbit polyclonal antibody (Biovendor), 0.13 [micro]g/mL in 1% BSA (w/v) in TBS-Tw was added and the plate was incubated for 1 h at 25[degrees]C. After 3 washes, we added 100 [micro]L/well of streptavidin-HRP conjugate (Research Diagnostics) 0.05 [micro]g/mL in 1% BSA (w/v) in TBS-Tw, incubated the plate for 30-min at 25[degrees]C, and then washed it. We then added 100 [micro]L/well of TMB substrate (KPL) and incubated the plate for another 10-min at 25[degrees]C. The reaction was stopped with 100 [micro]L/well sulfuric acid (0.2 mol/L). The developed color was determined by reading the plate on the microplate reader MRX II (Dynex) at a wavelength of 450 mn.
The protein content was determined by the Bradford method (Sigma-Aldrich) with recombinant EFABP (Biovendor) with >95% purity confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (data not shown) as a calibrator, prepared at concentrations of 40, 20, 10, 5, 2, and 1 [micro]g/L in 5% BSA (w/v) in TBS-Tw and 100 [micro]L directly pippeted into the wells.
The specificity of the immunoassay was confirmed by reactivity with recombinant EFABP (Abnova). No crossreactivity was found with recombinant human AFABP (Biovendor), IFABP (R&D Systems), LFABP (Abnova), or other related proteins: leptin, leptin receptor, adiponectin, resistin, and RELM-(3 at 100 [micro]g/L and IL-6 at 2 [micro]g/L (all provided by Biovendor). We observed 0.15% cross-reactivity with HAFBP (Prospec). No signal was found to the following animal sera: rabbit, horse, pig, chicken, sheep, and bovine.
To validate the assay we tested the accuracy and the precision. Skim breast milk samples from 2 participants with baseline EFABP concentrations of 5.8 and 12.4 [micro]g/L were enriched with increasing amounts of recombinant EFABP (+2.0, +4.0 and +10.0 [micro]g/L) and assayed. The mean recovery was 98%. We also tested by dilution skim breast milk samples from another 2 participants with baseline EFABP concentrations of 18.3 and 10.5 [micro]g/L (Fig. 1). The mean recovery was 112.4%.
The limit of detection was 0.5 [micro]g/L; intraassay CVs were 5.6% for low protein concentration samples (4.2 [micro]g/L) and 7.4% for a high protein concentrations (21.4 [micro]g/L); and interassay CVs were 6.2% and 8.1%, respectively.
[FIGURE 1 OMITTED]
We performed statistical analysis with Prism 4.0 statistical software (Graph Pad). Results are reported as mean (SE). We used tested correlations with Pearson correlation coefficient and determined differences between groups with the unpaired t-test. When biochemical values did not show gaussian distributions, we used Spearman correlation coefficient and Mann-Whitney test for comparison between groups. We used Welch's correction for significantly different variances, 1-sample t-test to compare single values in the hypertrophic newborn with the rest of the group, and 1-way ANOVA to compare differences in relation to the number of previous pregnancies or deliveries and for comparison between groups of children of various percentiles of birth weight. A P value of <0.05 was considered statistically significant.
Newborn boys had considerably higher absolute body weight at birth than girls (P = 0.025), but there was no difference in SDS of body weight, body length, ponderal index, or gestational age with respect to sex. Mothers of boys vs girls showed no statistically significant differences in age, body height, body weight, BMI before pregnancy or at the time of delivery, or body weight gain.
Mean (SE) adiponectin breast milk concentrations (n = 59) were 13.7 (0.8) [micro]g/L, range 3.9-30.4 [micro]g/L. Concentrations did not differ significantly in mothers who delivered boys (n = 27) vs girls (n = 32) [12.8 (1.0) vs 14.5 (1.1) [micro]g/L, P = 0.276], (Fig. 2). We found a positive correlation between adiponectin concentrations and the body weight of mothers before pregnancy (r = 0.288, P = 0.027), but no correlation was found with body weight at the time of delivery nor with the birth weight of newborns, either in absolute values (r = -0.119, P = 0.371, see Fig. 3A), or in SDS. There was no relationship with the number of previous pregnancies or deliveries or any other variable in mothers or newborns, nor with AFABP, EFABP, or leptin milk concentrations. We found a strong correlation between adiponectin concentrations before and after the second freezing/thawing cycle (n = 25, r = 0.894, P <0.0001) and a correlation between adiponectin concentrations in full breast milk and skim breast milk (n = 6, r = 0.958, P = 0.003).
[FIGURE 2 OMITTED]
[FIGURE 3 OMITTED]
Mean (SE) AFABP breast milk concentrations (n = 57) were 26.7 (4.4) [micro]g/L, range 1.2 to 137.0 [micro]g/L. AFABP concentrations were not gaussian in distribution (P = 0.002). Concentrations were not significantly different in mothers who delivered boys (n = 25) or girls (n = 32) [25.1 (5.2) vs 27.9 (6.8) [micro]g/L, P = 0.469]. We found a strong positive correlation between AFABP and EFABP (r = 0.593, P <0.0001) (Fig. 3B) but not between AFABP and leptin. We found a significant decrease in AFABP concentrations in mothers with a higher number of previous deliveries (1-way ANOVA, P = 0.040) (Fig. 4) but not pregnancies. No correlation was found between AFABP and birth weight of newborns either in absolute values or in SDS.
Mean (SE) EFABP breast milk concentrations (n = 57) were 18.1 (1.4) [micro]g/L, range 0.8 to 47.0 [micro]g/L. Concentrations were significantly higher in mothers who delivered boys (n = 25) than those who delivered girls (n = 32) [21.7 (2.3) vs 15.4 (1.7) [micro]g/L, P = 0.028] (Fig. 2). In the weight-selected group of newborns (2500-3500g, 15 boys and 29 girls), we did not see any difference between sexes in EFABP concentrations. An interesting finding was the positive correlation between EFABP and the birth weight of newborns (r = 0.266, P = 0.045) (Fig. 3C) and borderline correlation with SDS of birth weight (r = 0.237, P = 0.076). Correlations between EFABP and leptin, the number of previous pregnancies or deliveries, were not significant.
[FIGURE 4 OMITTED]
Mean (SE) leptin breast milk concentrations (n = 56) were 0.50 (0.05) [micro]g/L, range 0 to 1.37 [micro]g/L, (6 samples were below measurable range). One sample was excluded (4.42 [micro]g/L, more than 10 SD from the mean). Leptin concentrations were slightly, but not considerably, higher in mothers who delivered boys (n = 25) than girls (n = 31) [0.60 (0.07) vs 0.50 (0.07) ~g/L, P = 0.062] (Fig. 2). We found positive correlation between leptin breast milk concentrations and the body weight of mothers before pregnancy (r = 0.272, P = 0.043) and at the time of delivery (r = 0.370, P = 0.005); BMI before pregnancy (r = 0.397, P = 0.003) and at the time of delivery (r = 0.498, P <0.0001), and body weight gain during pregnancy (r = 0.267, P = 0.047) (Fig. 5A,B). There was no relationship between body weight or BMI before pregnancy and body weight gain during pregnancy. We found a positive correlation between leptin concentrations and the gestational age of the newborns (r = 0.266, P = 0.048) (Fig. 5C), and we found lower leptin concentrations in breast milk of mothers who delivered preterm babies (n = 8) than in those who delivered at term (n = 48) [0.30 (0.09) vs 0.60 (0.05) [micro]g/L, P = 0.026] (Fig. 6). We found a borderline correlation between leptin and birth weight of newborns in absolute values (r = 0.242, P = 0.072) but not in SDS (r = 0.066, P = 0.646).
TOTAL PROTEIN CONCENTRATION IN SKIM BREAST MILK SAMPLES
The mean (SE) total protein concentration in skim breast milk samples (n = 57) was 13.7 (0.5) g/L, ranging from 1 to 34.3 g/L. The values were not gaussian in distribution. There was a strong positive correlation with both AFABP (r = 0.482, P = 0.0001) and EFABP (r = 0.354, P = 0.007) but no correlation with adiponectin (r = -0.442, P = 0.744) or leptin (r = 0.206, P = 0.152).
After correction to total protein content in breast milk, we found a positive correlation between adiponectin and leptin (r = 0.320, P = 0.023). Moreover, there were similar appreciable Correlations found, as mentioned above (AFABP vs EFABP, r = 0.471, P = 0.0002; EFABP vs birth weight, r = 0.289, P = 0.029; and leptin vs body weight before pregnancy, r = 0.418, P = 0.003; at the time of delivery, r = 0.410, P = 0.003; BMI before pregnancy, r = 0.513, P = 0.0001; and at the time of delivery, r = 0.487, P = 0.0003).
We found no relationship between adiponectin, AFABP, EFABP, or leptin and age, body height of mothers, or ponderal index of newborns. Measurement results did not considerably differ for babies born by caesarian section (n = 11) compared with those born vaginally. Breast milk protein concentrations in mothers of newborns who developed neonatal icterus (n = 5), mothers with a history of GDM (n = 2), and mothers of hypotrophic newborns (n = 2) did not differ considerably from those of the rest of the study group, except in 1 mother with GDM who had a significantly higher concentration of leptin (P = 0.0049). In 1 hypertrophic boy, we found a significantly decreased concentration of adiponectin (P = 0.0134) and increased concentrations of leptin (P <0.0001) and EFABP (P <0.0001).
[FIGURE 5 OMITTED]
[FIGURE 6 OMITTED]
We demonstrated, for the first time, the presence of adiponectin, AFABP, and EFABP in human breast milk. Adiponectin serum concentrations are higher in women than in men (10,26,27), but in breast milk we did not find any considerable difference in adiponectin concentrations related to the sex of the newborn. Mean serum adiponectin concentrations reported by various authors (11-16,28,29) vary from 10 to 30 mg/L, 1000-fold higher than the concentrations in breast milk measured in this study, suggesting that adiponectin probably does not pass to breast milk from serum by simple diffusion. The composition of breast milk changes in the course of lactation, particularly during the first week after delivery, within one breastfeeding, and according to the gestational age of the newborn. Thus, adiponectin concentrations should be measured in various kinds of breast milk (preterm milk, colostrum, full milk during a longer period of lactation, foremilk, and hindmilk). Studies of the distribution and kinetics of adiponectin ingested by newborns should be conducted to show whether adiponectin survives the acid environment in the stomach and whether receptors are present in the gastrointestinal tract of newborns.
We found a positive correlation of adiponectin breast milk concentrations and the body weight of mothers before pregnancy. We do not have any explanation for this phenomenon, which we consider unlikely to be clinically important. Previous studies have shown that serum adiponectin concentrations correlate negatively with body weight, BMI, and the amount of body fat in adult humans (10), although Kotani et al. showed a positive correlation of adiponectin plasma concentrations with birth weight in newborns (15).
Although women with a history of GDM have hypoadiponectinaemia (30), a recent study did not show any relationship between adiponectin concentrations and glucose loading response or insulin sensitivity in pregnant women (31), and we did not find any difference in adiponectin breast milk concentrations in 2 mothers with GDM.
Adiponectin might be involved in fetal growth and development (27,32), but we did not find any remarkable difference in adiponectin breast milk concentrations in mothers who delivered hypotrophic or hypertrophic newborns. Nevertheless, because the nutritional programming hypothesis regarding the protective effects of breastfeeding is generally tested on preterm newborns (33), we suggest that adiponectin breast milk concentrations should be measured in these high-risk patients. Moreover, long-term follow-up studies are needed to assess the development of symptoms of metabolic syndrome in relationship to adiponectin breast milk concentrations.
Birth weight correlated positively with EFABP concentrations in breast milk. Results of an animal model study suggested that FABP deficiency increases the ratio of short (C14) to long (C18) fatty acid in adipose and muscle tissues and in circulating lipids and that absence of both FABPs led to significant protection against obesity, insulin resistance, type 2 diabetes mellitus, and fatty liver diseases (34,35). Low EFABP in human breast milk might be related to increasing concentrations of long chain fatty acids in breast milk, influencing the risk of insulin resistance.
The stoichiometry of AFABP:EFABP in breast milk was 1.5:1 in our study, which is very different from adipose tissue and surprisingly similar to the stoichiometry found in macrophages (36). We found a positive correlation between AFABP and EFABP rather than a compensatory regulation as reported in adipose tissue (36), indicating an important role for EFABP.
We demonstrated significantly higher EFABP concentrations in breast milk of mothers who delivered boys, but when we corrected for body weight regardless of sex we found that the positive correlation between EFABP concentrations and the body weight of newborns was not related to sex but to higher body weight in boys.
Our study corresponds to previous studies showing that leptin in human breast milk is related to maternal plasma leptin concentration and adiposity (37, 38), but other studies did not confirm this relationship (39). Although previous studies have shown that leptin concentrations did not considerably differ in preterm and fullterm breast milk (40), we found significant differences. Our findings may be attributable to the small number of mothers in the preterm group. On the other hand, these data are supported by the positive correlation between leptin and gestational age in our study. Dundar et al. (41) showed decreased breast milk leptin concentrations in mothers of children small for gestational age. We could not confirm their results because the majority of the children in our study were eutrophic.
In conclusion, it is well known that regulatory proteins may influence human growth and development (42). Identification and characterization of additional regulatory proteins in breast milk may lead to changes in the composition of infant formulas to ensure better nutritional support for newborns to improve their health later in adulthood.
This study was supported by research grants VZ MZO 00064203/6903 and GAUK 59/2004C. We thank Mrs. Tumlirova for excellent laboratory work.
Fax: 420-22443- 2020; e-mail firstname.lastname@example.org. Received November 1, 2005; accepted July 3, 2006.
(1.) Barker DJP, Clark PM. Fetal undernutrition and disease in later life. J Reprod Fertil 1997;2:105-12.
(2.) Lucas A. Programming by early nutrition: an experimental approach. J Nutr 1998;128:401S-406S.
(3.) Leeson CPM, Kattenhorn M, Deanfield JE, Lucas A. Duration of breast feeding and arterial distensibility in early adult life: population based study. BMJ 2001;322:643-7.
(4.) Das UN. Is obesity an inflammatory condition? Nutrition 2001;17: 953-66.
(5.) Plagemann A, Harder T, Franke K, Kohlhoff R. Long-term impact of neonatal breast feeding on body weight and glucose tolerance in children of diabetic mothers. Diabetes Care 2002;25:16-22.
(6.) Srinivasan M, Laychock SG, Hill DJ, Patel MS. Neonatal nutrition: metabolic programming of pancreatic islets and obesity. Exp Biol Med 2003;228:15-23.
(7.) Bonnet M, Delavaud C, Laud K, Gourdou I, Leroux C, Djiane J, et al. Mammary leptin synthesis, milk leptin and their putative physiological roles. Reprod Nutr Dev 2002;42:399-413.
(8.) Yamamoto Y, Hirose H, Saito I, Tomita M, Taniyama M, Matsubara K, et al. Correlation of the adipocyte derived protein adiponectin with insulin resistance index and serum high-density lipoproteincholesterol, independent of body mass index, in the Japanese population. Clin Sci 2002;103:137-42.
(9.) Haluzik M, Parizkova J, Haluzik MM. Adiponectin and its role in the obesity induced insulin resistance and related complications. Physiol Res 2004;53:123-9.
(10.) Nedvidkova J, Smitka K, Kopsky V, Hainer V. Adiponectin, an adipocyte-derived protein. Physiol Res 2005;54:133-40.
(11.) Iniguez G, Soto N, Avila A, Salazar T, Ong K, Dunger D, et al. Adiponectin levels in the first two years of life in a prospective cohort: Relations with weight gain, leptin levels and insulin sensitivity. J Clin Endocrinol Metab 2004;89:5500-3.
(12.) Cianflone K, Lu H, Smith J, Yu W, Wang H. Adiponectin, acylation stimulating protein and complement C3 are altered in obesity in very young children. Clin Endocrinol 2005;62:567-72.
(13.) Stefan N, Bunt JC, Salbe AD, Funahashi T, Matsuzawa Y, Tataranni PA. Plasma adiponectin concentrations in children: relationships with obesity and insulinemia. J Clin Endocrinol Metab 2002;87:4652-6.
(14.) Dunger D, Ong K. Abundance of adiponectin in the newborn. Clin Endocrinol 2004;61:416-7.
(15.) Kotani Y, Yokota I, Kitamura S, Matsuda J, Naito E, Kuroda Y. Plasma adiponectin levels in newborns are higher than those in adults and positively correlated with birth weight. Clin Endocrinol 2004;61:418-23.
(16.) Kamoda T, Saitoh H, Saito M, Sugiura M, Matsui A. Serum adiponectin concentrations in newborn infants in early postnatal life. Pediatr Res 2004;56:690-3.
(17.) Maeda N, Takahashi M, Funahashi T, Kihara S, Nishizawa H, Kishida K, et al. PPARy ligands increase expression and plasma concentrations of adiponectin, an adipose derived protein. Diabetes 2001;50:2094-9.
(18.) Lihn A, Yunk-Wook KK, Bruun J, Pedersen S, Richelsen B. Human in vitro and in vivo effects of thiazolidinediones on adiponectin. Obes Res 2003;11:A 35.
(19.) Ouchi N, Kobayashi H, Kihara S, Kumada M, Sato K, Inoue T, et al. Adiponectin stimulates angiogenesis by promoting cross-talk between AMP-activated protein kinase and Akt signaling in endothelial cells. J Biol Chem 2004;279:1304-9.
(20.) Haunerland NH, Spener F. Fatty acid-binding proteins-insights from genetic manipulations. Prog Lipid Res 2004;43:328-49.
(21.) Yang Y, Spitzer E, Kenney N, Zschiesche W, Li M, Kromminga A, et al. Members of the fatty acid binding protein family are differentiation factors for the mammary gland. J Cell Biol 1994; 127:1097-109.
(22.) Specht B, Bartetzko N, Hohoff C, Kuhl H, Franke R, Borchers T, et al. Mammary derived growth inhibitor is not a distinct protein but a mix of heart-type and adipocyte-type fatty acid-binding protein. J Biol Chem 1996;271:19943-9.
(23.) Shi YE, Ni J, Xiao G, Liu YE, Fuchs A, Yu G, et al. Antitumor activity of the novel human breast cancer growth inhibitor, mammaryderived growth inhibitor-related gene, MRG. Cancer Res 1997;57: 3084-91.
(24.) Hrebicek J, Janout V, Malincikova J, Horakova D, Cizek L. Detection of insulin resistance by simple quantitative insulin sensitivity check index QUICKI for epidemiological assessment and prevention. J Clin Endocrinol Metab 2002;87:144-7.
(25.) Xu A, Wang Y, Xu JY, Stejskal D, Tam S, Zhang J, et al. Adipocyte fatty acid binding protein is a plasma biomarker closely associated with obesity and metabolic syndrome. Clin Chem 2006;52: 405-13.
(26.) Das UN. Pathophysiology of metabolic syndrome X and its links to the perinatal period. Nutrition 2005;21:762-73.
(27.) Caminos JE, Nogueiras R, Gallego R, Bravo S, Tovar S, GarciaCaballero T, et al. Expression and regulation of adiponectin and receptor in human and rat placenta. J Clin Endocrinol Metab 2005;90:4276-86.
(28.) Fatouros IG, Tournis S, Leontsini D, Jamurtas AZ, Sxina M, Thomakos P, et al. Leptin and adiponectin responses in overweight inactive elderly following resistance training and detraining are intensity-related. J Clin Endocrinol Metab 2005;90:5970-7. epub ahead of print.
(29.) Suominen P. Evaluation of an enzyme immunometric assay to measure serum adiponectin concentrations. Clin Chem 2004;50: 219-21.
(30.) Heitritter SM, Solomon CG, Mitchell GF, Skali-Ounis N, Seely EW. Subclinical inflammation and vascular dysfunction in women with previous gestational diabetes mellitus. J Clin Endocrinol Metab 2005;90:3983-8.
(31.) Verhaeghe J, van Bree R, Lambin S, Caluwaerts S. Adipokine profile and C-reactive protein in pregnancy: effects of glucose challenge response versus body mass index. J Soc Gynecol Investig 2005;12:330-4.
(32.) Mazaki-Tovi S, Kanety H, Sivan E. Adiponectin and human pregnancy. Curr Diab Rep 2005;5:278-81.
(33.) Lucas A, Morley RM, Cole TJ, Gore SM. A randomised multicentre study of human milk versus formula and later development in preterm infants. Arch Dis Child 1994;70:F141-F146.
(34.) Maeda K, Cao H, Kono K, Gorgun CZ, Furuhashi M, Uysal KT, et al. Adipocyte/macrophage fatty acid binding proteins control integrated metabolic responses in obesity and diabetes. Cell Metab 2005;1:107-19.
(35.) Chavez JA, Summers SA. Characterizing the effects of saturated fatty acids on insulin signaling and ceramide and diacylglycerol accumulation in 3T3-L1 adipocytes and C2C12 myotubes. Arch Biochem Biophys 2003;419:101-9.
(36.) Hertzel AV, Bennaars-Eiden A, Bernlohr DA. Increased lipolysis in transgenic animals overexpressing the epithelial fatty acid binding protein in adipose cells. J Lipid Res 2002;43:2105-11.
(37.) Houseknecht KL, McGuire MK, Portocarrero CP, McGuire MA, Beerman K. Leptin is present in human milk and is related to maternal plasma leptin concentration and adiposity. Biochem Biophys Res Commun 1997;240:742-7.
(38.) Uysal FK, Onal EE, Aral YZ, Adam B, Dilmen U, Ardicolu Y. Breast milk leptin: its relationship to maternal and infant adiposity. Clin Nutr 2002;21:157-60.
(39.) Ucar B, Kirel B, Bor 0, Kilic FS, Dogruel N, Aydogdu SD, et al. Breast milk leptin concentrations in initial and terminal milk samples: relationships to maternal and infant plasma leptin concentrations, adiposity, serum glucose, insulin, lipid and lipoprotein levels. J Pediatr Endocrinol Metab 2000;13:149-56.
(40.) Resto M, O'Connor D, Leef K, Funanage V, Spear M, Locke R. Leptin levels in preterm human breast milk and infant formula. Pediatrics 2001;108:E15.
(41.) Dundar N0, Anal O, Dundar B, Ozkan H, Caliskan S, Buyukgebiz A. Longitudinal investigation of the relationship between breast milk leptin levels and growth in breast-fed infants. J Pediatr Endocrinol Metab 2005;18:181-7.
(42.) Bronsky J, Prusa R. Amylin fasting plasma levels are decreased in patients with osteoporosis. Osteopor Int 2004;15:243-7. D01: 10.1373/clinchem.2005.063032
JIRI BRONSKY, [1,2] * MICHAL KARPISEK,  EVA BRONSKA  MARTA PECHOVA  BARBORA JANCIKOVA,  HANA KOTOLOVA,  DAVID STEJSKAL,  RICHARD PRUTSA  AND JIRI NEVORAL, 
 Pediatric Gastroenterology Unit, Pediatric Clinic, 2nd Medical Faculty, Charles University and University Hospital Motol, Prague, Czech Republic.
 Department of Clinical Biochemistry and Pathobiochemistry, 2nd Medical Faculty, Charles University and University Hospital Motol, Prague, Czech Republic.
 Department of Human Pharmacology and Toxicology, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic.
 Nafional Institute of Public Health and 3rd Medical Faculty, Charles University and University Hospital Bulovka, Prague, Czech Republic.
 Department of Neonatology, 2nd Medical Faculty, Charles University and University Hospital Motol, Prague, Czech Republic.
 Department of Laboratory Medicine, Hospital Sternberk, Sternberk, Czech Republic.
 Nonstandard abbreviations: GDM, gestational diabetes mellitus; AFABP, adipocyte fatty acid binding protein; EFABP, epidermal fatty acid binding protein; BMI, body mass index; SDS, SD score.
* Address correspondence to this author at: Department of Pediatric Gastroenterology, Pediatric Clinic, 2nd Medical Faculty, Charles University and University Hospital Motol, V Uvalu 84, 150 06, Prague 5, Czech Republic.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||Endocrinology and Metabolism|
|Author:||Bronsky, Jiri; Karpisek, Michal; Bronska, Eva; Pechova, Marta; Jancikova, Barbora; Kotolova, Hana; S|
|Date:||Sep 1, 2006|
|Previous Article:||Multicapillary electrophoresis analysis of single-nucleotide sequence variations in the deoxycytidine kinase gene.|
|Next Article:||Lack of comparability of intact parathyroid hormone measurements among commercial assays for end-stage renal disease patients: implication for...|