The adipokine preadipocyte factor-1 is downregulated in preeclampsia and expressed in placenta.

BACKGROUND: Adipokines contribute to the development of preeclampsia (PE), a severe pregnancy complication which increases the future risk for cardiovascular and metabolic disease in both mother and newborn. Pre-adipocyte factor-1 (Pref-1) was recently introduced as a novel antiangiogenic and antiadipogenic adipokine. MATERIAL AND METHODS: Pref-1 was quantified in patients with PE (n=51) and healthy pregnant controls (n=51) during pregnancy, as well as 6 months after delivery (study population 1). Furthermore, Pref-1 was investigated in the immediate peripartal period and the placenta in 40 healthy pregnant women undergoing elective cesarean section (study population 2). RESULTS: In study population 1, median Pref-1 serum concentrations during pregnancy were significantly lower in women with PE (0.5 µg/l) as compared to healthy pregnant controls (0.7 µg/l) (p<0.001). Furthermore, Pref-1 serum concentrations were independently predicted by PE, leptin levels, and gestational age in this population. In both study populations, Pref-1 serum levels significantly decreased after delivery as compared to prepartal levels. Moreover, significant expression of Pref-1 was detected in placental tissue. CONCLUSION: Maternal Pref-1 serum concentrations are significantly decreased in PE. The pathophysiological significance of this regulation needs to be studied in more detail in future experiments.

Serum levels of sclerostin in cardiometabolic disorders during pregnancy.

OBJECTIVE: Sclerostin has recently been introduced as a novel osteocyte-secreted factor which is associated with an adverse metabolic profile. However, regulation of circulating sclerostin in cardiometabolic disorders during pregnancy including gestational diabetes mellitus (GDM) and preeclampsia (PE) has not been comprehensively assessed, so far. METHODS: Serum levels of sclerostin were quantified in 72 women with GDM and in 72 healthy, pregnant, gestational age-matched controls (study population 1). Furthermore, circulating sclerostin was assessed in 51 women with PE as compared to 51 pregnant controls in a second cohort (study population 2). RESULTS: In the first study population (GDM), median [interquartile range] sclerostin levels were not significantly different in women with GDM as compared to controls (GDM: 19.2 [8.1]pmol/l; controls: 18.6 [7.1]pmol/l; p=0.906). Interestingly, C reactive protein was a negative and independent predictor of circulating sclerostin in the GDM cohort in multivariate analysis. In study population 2 (PE), serum levels of sclerostin were not different between women with PE and controls (PE: 18.8 [9.2]pmol/l; controls: 19.3 [8.8]pmol/l; p=0.504). Furthermore, the osteocyte-secreted factor was not related to any metabolic and gestational parameter in this cohort. CONCLUSIONS: Sclerostin serum levels are not associated with an adverse metabolic profile during pregnancy in women with GDM and PE. The physiological significance of different associations of circulating sclerostin between pregnancy and non-pregnant status needs to be determined in future experiments.

Serum levels of fibroblast growth factor-21 are increased in chronic and acute renal dysfunction.

OBJECTIVE: Fibroblast growth factor (FGF)-21 has recently been introduced as a circulating adipokine which reverses insulin resistance and obesity in rodents. In this study, regulation of FGF-21 in renal dysfunction was elucidated in both chronic kidney disease (CKD) and acute kidney dysfunction (AKD). STUDY DESIGN AND METHODS: Serum concentrations of total FGF-21 were quantified by enzyme-linked immunosorbent assay in 499 patients with CKD stages 1-5 (study population 1). Furthermore, total FGF-21 was determined before and within 30 h after unilateral nephrectomy, a model of AKD, in 32 patients (study population 2). FGF-21 levels were correlated to anthropometric and biochemical parameters of renal function, glucose and lipid metabolism, as well as inflammation, in both studies. RESULTS: In study population 1, median [interquartile range] circulating FGF-21 adjusted for age, gender and body mass index was significantly different between CKD stages with highest values detectable in stage 5 (stage 1: 86·4 [132·9]; 2: 206·4 [223·1]; 3: 289·8 [409·3]; 4: 591·3 [789·0]; 5: 1918·1 [4157·0] ng/l). Furthermore, estimated glomerular filtration rate remained a strong independent and negative predictor of FGF-21. In study population 2, FGF-21 increased significantly postsurgically (325·0 [984·0] ng/l) as compared to presurgical values (255·5 [243·0] ng/l). Furthermore, relative changes of FGF-21 were independently and positively predicted by relative changes of creatinine. CONCLUSIONS: We demonstrate that circulating FGF-21 is increased in both CKD and AKD. Our results suggest renal excretion as a major route for FGF-21 elimination. The pathophysiological significance of these findings needs to be elucidated in more detail.

Serum levels of irisin in gestational diabetes mellitus during pregnancy and after delivery.

OBJECTIVE: Irisin has recently been introduced as a novel an exercise-inducible myokine which improves glucose metabolism in mice. However, regulation of circulating irisin in gestational diabetes mellitus (GDM) and in the peripartal period has not been assessed so far. METHODS: Circulating irisin was quantified in 74 GDM patients and in 74 healthy, pregnant, gestational age-matched controls. In a subset of these patients (44 GDM, 41 controls), postpartum follow-up data were also available. In a second study population of 40 healthy women with singleton pregnancies undergoing elective Cesarean section, irisin was assessed in maternal serum before and within 24h after delivery, as well as in umbilical cord blood and in placental tissue. RESULTS: In the first study population, median [interquartile range] irisin levels were significantly higher in GDM patients as compared to controls after delivery (previous GDM: 446.3 [146.9]µg/l; controls: 378.0 [111.4]µg/l) but not during pregnancy (GDM: 482.1 [132.1]µg/l; controls: 466.6 [178.0]µg/l). Interestingly, fasting insulin (FI) was independently and positively associated with serum irisin in multivariate analysis during pregnancy. In agreement with these findings, relative changes (ratio) of FI independently and positively predicted relative changes of irisin (ratio) in the second study population. CONCLUSIONS: The myokine irisin is independently associated with FI in pregnancy. The physiological significance of these findings needs to be assessed in future experiments.

Serum levels of the adipokine fibroblast growth factor-21 are increased in preeclampsia.

BACKGROUND: Preeclampsia (PE) is a serious cardiovascular complication in pregnancy, which is associated with an increased future metabolic and cardiovascular risk for mother and newborn. Fibroblast growth factor (FGF)-21 was recently introduced as a novel adipokine improving glucose metabolism in vitro and in vivo. MATERIAL AND METHODS: We investigated serum FGF-21 levels in patients with PE (n=51) as compared to healthy, age-matched controls (n=51) during and 6 months after pregnancy. Furthermore, association of FGF-21 with markers of renal function, glucose and lipid metabolism, as well as inflammation, was elucidated in all individuals. RESULTS: Median maternal FGF-21 serum concentrations adjusted for body mass index and gestational age at blood sampling were significantly, almost 3-fold increased in PE patients (309.6 ng/l) as compared to healthy, age-matched pregnant women (105.2 ng/l) (p<0.001). Furthermore, FGF-21 concentrations were independently and positively correlated with triglycerides whereas an independent and negative association was observed with glomerular filtration rate and low density lipoprotein (LDL) cholesterol in pregnant women. Moreover, FGF-21 serum levels significantly decreased in former PE patients 6 months after pregnancy approaching levels found in control patients. CONCLUSIONS: Maternal FGF-21 serum concentrations are significantly increased in PE during pregnancy. Furthermore, triglycerides, glomerular filtration rate, and LDL cholesterol are independent predictors of circulating FGF-21 in pregnant women.

Association between TGFß1 Levels in Cord Blood and Weight Progress in the First Year of Life.

Transforming growth factor beta-1 (TGFß1) is an adipokine secreted from adipose tissue, placental tissue and immune cells with a role in cell proliferation, cell apoptosis and angiogenic proliferation. The role of TGFß1 in pregnancy and child growth and the source of cord TGFß1 are yet unknown. In this study, we sought to clarify the correlation of TGFß1 levels with parameters of intrauterine growth and child growth during the first year of life, and to determine whether their source is primarily of fetal or maternal origin. Serum samples and anthropometric measurements were obtained from the LIFE Child cohort of 79 healthy mother-child pairs. Measurements were conducted using enzyme-linked immunosorbent assays. Statistical analyses including Mann-Whitney U-test, correlation analyses and linear regression analyses were performed using GraphPad Prism and R. TGFß1 levels were significantly higher in cord than in maternal serum, suggesting a fetal origin. Multivariate regression analyses revealed strong positive associations between cord TGFß1 levels at birth and child weight at U6. Furthermore, cord TGFß1 was significantly correlated with child weight at approximately one year of age. An increase of 10,000 pg/mL in cord TGFß1 concentrations at birth was associated with a higher body weight of 201 g at roughly one year of age when adjusted for sex.

Leptin Improves Parameters of Brown Adipose Tissue Thermogenesis in Lipodystrophic Mice.

Lipodystrophy syndromes (LD) are a heterogeneous group of very rare congenital or acquired disorders characterized by a generalized or partial lack of adipose tissue. They are strongly associated with severe metabolic dysfunction due to ectopic fat accumulation in the liver and other organs and the dysregulation of several key adipokines, including leptin. Treatment with leptin or its analogues is therefore sufficient to reverse some of the metabolic symptoms of LD in patients and in mouse models through distinct mechanisms. Brown adipose tissue (BAT) thermogenesis has emerged as an important regulator of systemic metabolism in rodents and in humans, but it is poorly understood how leptin impacts BAT in LD. Here, we show in transgenic C57Bl/6 mice overexpressing sterol regulatory element-binding protein 1c in adipose tissue (Tg (aP2-nSREBP1c)), an established model of congenital LD, that daily subcutaneous administration of 3 mg/kg leptin for 6 to 8 weeks increases body temperature without affecting food intake or body weight. This is associated with increased protein expression of the thermogenic molecule uncoupling protein 1 (UCP1) and the sympathetic nerve marker tyrosine hydroxylase (TH) in BAT. These findings suggest that leptin treatment in LD stimulates BAT thermogenesis through sympathetic nerves, which might contribute to some of its metabolic benefits by providing a healthy reservoir for excess circulating nutrients.

Adipocyte Fatty Acid-Binding Protein 4 is Altered in Growth Discordant Dichorionic, but not in Monochorionic Twins.

CONTEXT: The fetal period has a critical and long-lasting impact on the regulation of metabolic processes and a life-long predisposition for obesity and metabolic syndrome. The exact mechanisms are unknown, but epigenetic regulation likely plays a major role. Twins represent an excellent model to study these mechanisms, as they share the same intrauterine environment and similar or even the same genetic information. We examined cord blood levels of adipocyte fatty-acid binding protein 4 (A-FABP or FABP4), a novel adipokine correlated with obesity and metabolic disease in children and adults. OBJECTIVE: To examine A-FABP levels in the cord blood of twins with concordant and discordant growth and in singletons with intrauterine growth restriction (IUGR). DESIGN: Cohort study of 36 twin pairs (25 growth concordant and 11 growth discordant), and 42 singleton pregnancies (28 IUGR and 13 normally grown controls, 1 HELLP). OUTCOME MEASURES: Cord blood A-FABP levels measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: A-FABP levels were higher in the smaller of growth discordant dichorionic (DC) twins versus their co-twins (109.46 ±â€…62.80 ng/mL vs. 72.93 ±â€…36.66 ng/mL, P = 0.028). A-FABP was negatively correlated with birth weight and gestational age (P < 0.001), but not with birth weight z-score (P = 0.37). CONCLUSIONS: Increased A-FABP levels might be associated with an increased metabolic risk in growth-restricted (twins) and prematurely born infants.

Lipocalin-2 is induced by interleukin-1beta in murine adipocytes in vitro.

Lipocalin-2 (Lcn2) has recently been isolated as an adipocyte-secreted acute phase reactant that plays a role in insulin resistance, obesity, and atherosclerotic disease. In the current study, we determined regulation of Lcn2 by the proinflammatory and insulin resistance-inducing cytokine interleukin (IL)-1beta in 3T3-L1 and brown adipocytes by relative real-time reverse transcription-polymerase chain reaction. Interestingly, IL-1beta dramatically induced Lcn2 mRNA in both adipocyte models. Furthermore, Lcn2 protein secretion was dramatically upregulated in 3T3-L1 adipocytes after 24 h of IL-1beta treatment. Experiments using pharmacological inhibitors indicated that IL-1beta-induced Lcn2 expression is mediated via nuclear factor kappaB and janus kinase 2. Taken together, our results show an upregulation of Lcn2 by IL-1beta in fat cells implicating a potential role of this adipocyte-secreted acute phase reactant in the development of insulin resistance, obesity, and associated disorders including cardiovascular disease.

Amyloid precursor protein expression is induced by tumor necrosis factor alpha in 3T3-L1 adipocytes.

Amyloid precursor protein (APP) has been characterized as an adipocyte-secreted protein that might contribute to obesity-related insulin resistance, inflammation, and dementia. In the current study, regulation of APP by the proinflammatory and insulin resistance-inducing cytokine tumor necrosis factor (TNF) alpha was determined in 3T3-L1 adipocytes. Interestingly, APP protein synthesis and mRNA expression were significantly increased by TNFalpha in a time-dependent manner with maximal induction observed after 24 h of treatment. Furthermore, TNFalpha induced APP mRNA expression dose-dependently with maximal 6.4-fold upregulation seen at 100 ng/ml effector. Moreover, inhibitor experiments suggested that TNFalpha-induced APP expression was mediated by nuclear factor kappa B. Taken together, we show for the first time a potent upregulation of APP by TNFalpha suggesting a potential role of this adipocyte-secreted protein in TNFalpha-induced insulin resistance and inflammatory disease.

Secretory products from human adipocytes stimulate proinflammatory cytokine secretion from human endothelial cells.

Hyperplasia and hypertrophy of fat cells can be found in obesity and increased adiposity is associated with endothelial dysfunction as an early event of atherosclerosis. However, it is unclear whether human adipocytes directly influence endothelial protein secretion. To study the crosstalk between fat and endothelial cells, human umbilical venous endothelial cells (HUVECs) were cultured in infranatants (Adipo) of primary differentiated human adipocytes. Interestingly, significantly increased secretion of 23 cytokines and chemokines from HUVECs was detected in four independent experiments after Adipo stimulation by protein array analysis detecting a total of 174 different proteins. Among those, time-dependent Adipo-induced upregulation of cytokine secretion in HUVECs was confirmed by ELISA for interleukin (IL)-8, monokine induced by gamma interferon, macrophage inflammatory protein (MIP)-1beta, MIP-3alpha, monocyte chemoattractant protein-1, and IL-6. Factors besides adiponectin, leptin, resistin, and tumor necrosis factor alpha appear to mediate these stimulatory effects. Our findings suggest that endothelial cell secretion is significantly influenced towards a proinflammatory pattern by adipocyte-secreted factors.

Interleukin-1beta induces the novel adipokine chemerin in adipocytes in vitro.

Chemerin has recently been characterized as a novel adipokine playing a crucial role in adipocyte differentiation and insulin signalling. In the current study, the impact of insulin resistance-inducing and proinflammatory interleukin (IL)-1beta on chemerin protein secretion and mRNA expression was determined in 3T3-L1 adipocytes. Interestingly, IL-1beta significantly induced chemerin protein secretion almost 1.3-fold from 5.89 ng/ml (basal) to 7.52 ng/ml. Furthermore, chemerin mRNA synthesis was significantly stimulated by IL-1beta in a dose-dependent fashion with 1.5-fold induction seen at IL-1beta concentrations as low as 0.07 ng/ml and maximal 2.6-fold upregulation found at 2 ng/ml effector. Induction of chemerin mRNA by IL-1beta was time-dependent in both 3T3-L1 adipocytes and brown fat cells. Signalling studies suggested that Janus kinase 2, nuclear factor kappa B, p44/42 mitogen-activated protein kinase, and phosphatidylinositol 3-kinase are involved in IL-1beta-induced chemerin mRNA expression. Furthermore, recombinant chemerin downregulated insulin-stimulated glucose uptake. Taken together, we show that chemerin is upregulated in fat cells by IL-1beta and might modulate the effects of IL-1beta on adipocyte metabolism and insulin sensitivity.

Leptin decreases circulating inflammatory IL-6 and MCP-1 in mice.

Leptin influences inflammation and immune response. Dose-dependent effects of leptin on biomarkers of inflammation have not been studied in vivo, so far. Leptin-deficient low-density lipoprotein receptor (LDLR) knockout (LDLR-/- ;ob/ob) female mice were treated with three different leptin doses or saline for 12 weeks. The effect of leptin on plasma interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1 concentrations and Il-6 and Mcp-1 mRNA expression in vivo were assessed. Macrophage infiltration in epididymal adipose tissue (epiAT) after leptin treatment was determined by quantitative immunohistochemical analysis. Aortic root atherosclerotic lesions were analyzed by oil red O staining. Mean plasma IL-6 and MCP-1 decreased significantly in the 3.0 mg/kg BW/day group as compared to control mice (both P < 0.01). Messenger RNA expression of Il-6 and Mcp-1 was significantly down-regulated by leptin treatment in different adipose tissues in vivo. Characteristic crown-like structures formed by adipose tissue macrophages were significantly reduced by leptin treatment in epiAT. Recombinant leptin dose-dependently diminished plaque area in the aortic root. Leptin administration within the subphysiological to physiological range diminishes circulating pro-inflammatory IL-6 and MCP-1. Reduction of Il-6 and Mcp-1 gene expression in adipose tissue, as well as decreased adipose tissue macrophage infiltration might contribute. © 2018 BioFactors, 45(1):43-48, 2019.

Serum levels of the adipokine vaspin in relation to metabolic and renal parameters.

CONTEXT: Recently, vaspin was identified as an insulin-sensitizing adipokine. However, regulation of this adipocyte-secreted factor in human disease has not been determined. OBJECTIVE: We investigated vaspin serum concentrations in diabetic and nondiabetic patients on chronic hemodialysis (CD) as compared with controls with a glomerular filtration rate (GFR) above 50 ml/min. DESIGN: Vaspin was quantified by ELISA in control (n = 60) and CD (n = 60) patients and correlated to clinical and biochemical measures of renal function, glucose, and lipid metabolism, as well as inflammation, in both groups. RESULTS: Mean serum vaspin concentrations were not significantly different between CD patients and controls. Circulating vaspin was significantly lower in males (0.6 +/- 0.9 microg/liter) as compared with females (1.3 +/- 1.5 microg/liter) and was decreased in insulin-treated subjects. In univariate analyses, vaspin levels positively correlated with age and high-density lipoprotein cholesterol and negatively with waist-to-hip ratio and GFR in control patients, whereas the adipokine was negatively associated with GFR and C-reactive protein (CRP) in CD patients. In multivariate analyses, age and gender were independently associated with vaspin in controls, whereas gender, GFR, and CRP independently predicted circulating vaspin in CD patients. CONCLUSIONS: Vaspin levels are significantly higher in women, and gender is an independent predictor of circulating vaspin in both control and CD patients. In addition, age independently predicts vaspin in control patients, whereas GFR and CRP are independently associated with this adipokine in CD patients. In contrast, circulating vaspin is not independently associated with markers of glucose and lipid metabolism.

The adipokine SAA3 is induced by interleukin-1beta in mouse adipocytes.

Serum amyloid A (SAA) 3 has been characterized as an inflammatory adipocyte-secreted acute-phase reactant. In the current study, regulation of SAA3 by the proinflammatory and insulin resistance-inducing cytokine interleukin (IL)-1beta was determined in 3T3-L1 and brown adipocytes. Interestingly, SAA3 mRNA and protein synthesis were dramatically increased by IL-1beta in a time-dependent fashion with maximal induction after 24 h. Furthermore, IL-1beta significantly induced SAA3 mRNA expression dose-dependently with maximal 36.4-fold upregulation seen at 2 ng/ml effector. Moreover, IL-1beta-induced SAA3 expression was mediated by nuclear factor-kappaB and janus kinase 2. Taken together, our data show a potent upregulation of SAA3 by IL-1beta.

Endogenous soluble receptor for advanced glycation endproducts is increased in preeclampsia.

OBJECTIVE: Preeclampsia is a serious complication in pregnancy with an increased future cardiovascular risk for both mother and newborn. Recently, low levels of endogenous soluble receptor for advanced glycation endproducts (esRAGE) have been associated with increased cardiovascular risk. In the current study, we investigated esRAGE serum levels in patients with preeclampsia as compared to healthy gestational age-matched controls. METHODS: esRAGE was quantified by enzyme-linked immunosorbent assay in controls and patients with preeclampsia during pregnancy (control: n = 20, preeclampsia: n = 16) and 6 months after delivery (control: n = 19, preeclampsia: n = 15). Furthermore, esRAGE was correlated to clinical and biochemical measures of renal function, glucose and lipid metabolism, as well as inflammation. RESULTS: During pregnancy, median maternal serum esRAGE concentrations were more than three-fold higher in patients with preeclampsia (200 ng/l) than in controls (63 ng/l) (P < 0.01). Furthermore, esRAGE levels positively correlated with age, blood pressure, creatinine, adiponectin, and C-reactive protein, whereas a negative correlation existed with fasting insulin and the homeostasis model assessment of insulin resistance index. In multivariate analyses, homeostasis model assessment of insulin resistance and C-reactive protein independently predicted esRAGE serum levels and explained 44% of the variation in esRAGE concentrations. Surprisingly, median esRAGE concentrations 6 months after delivery were significantly lower in former patients with preeclampsia (270 ng/l) than in controls (342 ng/l) in contrast to the results obtained during pregnancy. CONCLUSION: We showed that maternal esRAGE concentrations are significantly increased in patients with preeclampsia during pregnancy. Here, insulin sensitivity and inflammatory status independently predict serum esRAGE levels.

Serum levels of adipocyte fatty acid-binding protein (AFABP) are increased in chronic haemodialysis (CD).

OBJECTIVE: Adipocyte fatty acid-binding protein (AFABP) was recently introduced as an adipocyte-expressed factor, serum levels of which independently correlate with the development of the metabolic syndrome and cardiovascular disease in humans. In the current study, we investigated renal elimination of this protein by comparing circulating AFABP levels in patients on chronic haemodialysis (CD) with controls. We hypothesized that if renal filtration is a significant route of elimination of AFABP, it would accumulate in CD patients. PATIENTS AND MEASUREMENTS: AFABP was determined by ELISA in control (n = 60) and CD (n = 60) patients and correlated to clinical and biochemical measures of renal function, glucose and lipid metabolism, as well as inflammation, in both groups. RESULTS: Median serum AFABP levels were more than 10-fold higher in CD patients (510.9 +/- 294.7 microg/l) as compared to controls (44.3 +/- 35.2 microg/l). Furthermore, CD independently predicted AFABP concentrations in multiple regression analysis. In addition, body mass index and free fatty acids were independently associated with circulating AFABP. CONCLUSIONS: Renal filtration appears as an important route of elimination of AFABP. Future studies should elucidate whether this adipocyte-expressed factor contributes to the increased risk of cardiovascular disease found in end-stage renal disease.

Serum levels of the adipokine visfatin are increased in pre-eclampsia.

OBJECTIVE: Pre-eclampsia (PE) is a serious cardiovascular complication in pregnancy which shares risk factors with the metabolic syndrome including insulin resistance and obesity. Recently, visfatin was introduced as a novel insulin-mimetic adipokine which is up-regulated when weight is gained. In the current study, we investigated visfatin serum levels in pre-eclamptic patients as compared to healthy gestational age-matched controls. PATIENTS AND MEASUREMENTS: Visfatin was quantified by ELISA in control (n = 20) and PE (n = 15) patients. Furthermore, visfatin was correlated to clinical and biochemical measures of renal function, glucose and lipid metabolism, as well as inflammation. RESULTS: Mean maternal visfatin serum levels adjusted for maternal age were about twofold up-regulated in PE (31.1 +/- 23.4 microg/l) as compared to controls (15.7 +/- 23.1 microg/l). Furthermore, visfatin concentrations correlated positively with age, blood pressure, creatinine, free fatty acids (FFA), IL-6 and C reactive protein (CRP), whereas a negative correlation was found with fasting insulin and the HOMA-insulin resistance index (HOMA-IR). In multivariate analyses, HOMA-IR and CRP remained independently associated with visfatin serum levels and explained 58% of the variation in visfatin concentrations. CONCLUSIONS: We show that maternal visfatin levels are significantly increased in PE patients. Furthermore, insulin sensitivity and inflammatory status independently predict serum visfatin levels.

Serum levels of the adipokine adipocyte fatty acid-binding protein are increased in preeclampsia.

BACKGROUND: Preeclampsia (PE) is a serious complication of pregnancy which is associated with an increased future metabolic and cardiovascular risk for both mother and newborn. Recently, adipocyte fatty acid-binding protein (AFABP) was introduced as a novel adipokine, serum levels of which independently correlate with the development of the metabolic syndrome and cardiovascular disease in humans. In this study, we investigated serum concentrations of the adipokine AFABP in patients with PE as compared to healthy controls of similar gestational age. METHODS: AFABP serum levels were quantified by enzyme-linked immunosorbent assay (ELISA) in control (n = 20) and PE (n = 16) patients. Furthermore, AFABP was correlated to clinical and biochemical measures of renal function, glucose, and lipid metabolism, as well as inflammation. RESULTS: Mean maternal AFABP concentrations were significantly elevated in PE (24.5 +/- 9.7 microg/l) as compared to controls (14.8 +/- 7.1 microg/l). Furthermore, AFABP serum levels correlated positively with age, body mass index (BMI), blood pressure, serum creatinine, free fatty acids (FFAs), leptin, and C-reactive protein (CRP). In multivariate analyses, BMI and serum creatinine remained independently associated with AFABP concentrations and explained 58% of the variation in AFABP levels. CONCLUSION: We demonstrate that maternal AFABP serum concentrations are significantly increased in PE. Furthermore, BMI and serum creatinine are independent predictors of circulating AFABP.

Leptin restores markers of female fertility in lipodystrophy.

OBJECTIVES: Female reproductive dysfunction occurs in patients with pathological loss of adipose tissue, i.e. lipodystrophy (LD). However, mechanisms remain largely unclear and treatment effects of adipocyte-derived leptin have not been assessed in LD animals. METHODS: In the current study, C57Bl/6 LD mice on a low-density lipoprotein receptor knockout background were treated with leptin or saline for 8 weeks and compared to non-LD controls. RESULTS: The number of pups born was 37% lower in breeding pairs consisting of LD female mice x non-LD male mice (n = 3.3) compared to LD male mice x non-LD female mice (n = 5.2) (p < 0.05). Mean uterus weight was significantly lower in the saline-treated LD group (18.8 mg) compared to non-LD controls (52.9 mg; p < 0.0001) and increased significantly upon leptin treatment (46.5 mg; p < 0.001). The mean number of corpora lutea per ovary was significantly lower in saline-treated LD animals compared to non-LD controls (p < 0.01) and was restored to non-LD control levels by leptin (p < 0.05). Mechanistically, mRNA expression of ovarian follicle-stimulating hormone receptor (p < 0.01) and estrogen receptor ß (p < 0.05), as well as of pituitary luteinizing hormone ß subunit (p < 0.001) and follicle-stimulating hormone ß subunit (p < 0.05), was significantly upregulated in LD mice compared to non-LD controls. In addition, mean time to vaginal opening as a marker of puberty onset was delayed by 12.5 days in LD mice (50.9 days) compared to non-LD controls (38.4 days; p < 0.001). CONCLUSIONS: Female LD animals show impaired fertility which is restored by leptin. Future studies should assess leptin as a subfertility treatment in human leptin-deficiency disorders.