Fetuin B in white adipose tissue induces inflammation and is associated with peripheral insulin resistance in mice and humans.

OBJECTIVE: Fetuin B is a steatosis-responsive hepatokine that causes glucose intolerance in mice, but the underlying mechanisms remain incompletely described. This study aimed to elucidate the mechanisms of action of fetuin B by investigating its putative effects on white adipose tissue metabolism. METHODS: First, fetuin B gene and protein expression was measured in multiple organs in mice and in cultured adipocytes. Next, the authors performed a hyperinsulinemic-euglycemic clamp in mice and in humans to examine the link between white adipose tissue fetuin B content and indices of insulin sensitivity. Finally, the effect of fetuin B on inflammation was investigated in cultured adipocytes by quantitative polymerase chain reaction and full RNA sequencing. RESULTS: This study demonstrated in adipocytes and mice that fetuin B was produced and secreted by the liver and taken up by adipocytes and adipose tissue. There was a strong negative correlation between white adipose tissue fetuin B content and peripheral insulin sensitivity in mice and in humans. RNA sequencing and polymerase chain reaction analysis revealed that fetuin B induced an inflammatory response in adipocytes. CONCLUSIONS: Fetuin B content in white adipose tissue strongly associated with peripheral insulin resistance in mice and humans. Furthermore, fetuin B induced a proinflammatory response in adipocytes, which might drive peripheral insulin resistance.

Viscoelastic Properties of Zona Pellucida of Oocytes Characterized by Transient Electrical Impedance Spectroscopy.

The success rate in vitro fertilization is significantly linked to the quality of the oocytes. The oocyte's membrane is encapsulated by a shell of gelatinous extracellular matrix, called zona pellucida, which undergoes dynamic changes throughout the reproduction cycle. During the window of highest fertility, the zona pellucida exhibits a softening phase, while it remains rigid during oocyte maturation and again after fertilization. These variations in mechanical properties facilitate or inhibit sperm penetration. Since successful fertilization considerably depends on the state of the zona pellucida, monitoring of the hardening process of the zona pellucida is vital. In this study, we scrutinized two distinct genetic mouse models, namely, fetuin-B wild-type and fetuin-B/ovastacin double deficient with normal and super-soft zona pellucida, respectively. We evaluated the hardening with the help of a microfluidic aspiration-assisted electrical impedance spectroscopy system. An oocyte was trapped by a microhole connected to a microfluidic channel by applying suction pressure. Transient electrical impedance spectra were taken by microelectrodes surrounding the microhole. The time-depending recovery of zona pellucida deflections to equilibrium was used to calculate the Young's modulus and, for the first time, absolute viscosity values. The values were obtained by fitting the curves with an equivalent mechanical circuit consisting of a network of dashpots and springs. The observer-independent electrical readout in combination with a fitting algorithm for the calculation of the viscoelastic properties demonstrates a step toward a more user-friendly and easy-to-use tool for the characterizing and better understanding of the rheological properties of oocytes.

Association of Fetuin-B with Subclinical Atherosclerosis in Obese Chinese Adults.

AIM: We aimed to explore the independent associations of serum Fetuin-B and common genetic variants in FETUB locus with subclinical atherosclerosis. METHODS: A cross-sectional study of 1,140 obese adults, who underwent serum Fetuin-B testing, hepatic ultrasonography scanning, genotyping on four tagging single nucleotide polymorphisms (SNPs) in FETUB locus and atherosclerosis detection, was conducted in Xiamen, China. RESULTS: Increasing tertiles of brachial ankle pulse wave velocity (ba-PWV) were significantly associated with higher prevalence of nonalcoholic fatty liver disease (NAFLD) (48.8%, 61.5%, and 70.5% for tertiles of 1-3, respectively, p＜0.001) and serum Fetuin-B (3.85±1.39, 4.09±1.40, and 4.27±1.46 µg/ml, p=0.047). Multivariable linear regression analyses with adjustment for potential confounding factors, even NAFLD per se, showed that serum Fetuin-B were significantly and positively associated with ba-PWV, with standardized regression coefficients (ß) ranging from 0.055 to 0.075 (all p-values ＜0.05) in different models. However, the significant relationship between serum Fetuin-B and ba-PWV disappeared with further adjustment for insulin resistance. Serum Fetuin-B was not significantly associated with ankle-brachial index (ABI). All genotypes of the four tested FETUB tagging SNPs were not significantly associated with either ba-PWV or ABI with adjustment for potential confounding factors. CONCLUSION: Serum Fetuin-B was positively associated with ba-PWV and may link liver fat accumulation to subclinical atherosclerosis via insulin resistance.

Colorimetric Paper-Based Immunosensor for Simultaneous Determination of Fetuin B and Clusterin toward Early Alzheimer's Diagnosis.

Alzheimer's disease is a devastating condition characterized by a progressive and slow brain decay in elders. Here, we developed a paper-based lateral flow immunoassay for simultaneous and fast determination of Alzheimer's blood biomarkers, fetuin B and clusterin. Selective antibodies to targeted biomarkers were immobilized on gold nanoparticles (AuNPs) and deposited on paper pads. After adding the sample on the paper-based device, the biofluid laterally flows toward the selective antibody, permitting AuNP-Ab accumulation on the test zone, which causes a color change from white to pink. Image analysis was performed using a customized algorithm for the automatic recognition of the area of analysis and color clustering. Colorimetric detection was compared to electrochemical methods for the precise quantification of biomarkers. The best performance was found for the color parameter "L*". Good linearity (R2 = 0.988 and 0.998) and reproducibility (%RSD = 2.79% and 1.82%, N = 3) were demonstrated for the quantification of fetuin B and clusterin, respectively. Furthermore, the specificity of the immunosensor was tested on mixtures of proteins, showing negligible cross-reactivity and good performance in complex environments. We believe that our biosensor has a potential for early-stage diagnosis of Alzheimer's disease and toward a better understanding of Alzheimer's developing mechanisms.

Serum proteome changes and accelerated reduction of fat mass after laparoscopic gastric plication in morbidly obese patients.

Laparoscopic Gastric Plication (LGP) is a relatively new bariatric surgical procedure which no part of the stomach is removed. It is not clearly understood how LGP leads to fatty tissue reduction. We aimed to investigate the impact of LGP on serum proteome and understand molecular mechanisms of LGP-induced weight loss post-surgery. A Prospective observational study of 16 obese individuals who underwent LGP was performed. A Label-free quantitative shotgun proteomics approach was used to compare serum proteome of subjects before surgery with serum of the same individuals 1 to 2 months post-surgery (T1) and 4 to 5 months post-surgery (T2). The proteome analysis revealed that 48 proteins were differentially regulated between pre-surgery and T1, and seven proteins between pre-surgery and T2 of which six proteins were shared between the two timepoints. Among differentially regulated proteins, four proteins (SRGN, FETUB, LCP1 and CFP) have not previously been described in the context of BMI/weight loss. Despite few differences following LGP, most regulated serum proteins are in accordance with alternative weight loss procedures. Pathway analysis revealed changes to lipid- and inflammatory pathways, including PPARα/RXRα, LXR/RXR and FXR/RXR activation, especially at T1. At T2, the pathways related to inflammation and immune system are most affected. SIGNIFICANCE: Among the available clinical therapies for morbid obesity, bariatric surgery is considered as the most effective approach to achieve long-term weight loss, alongside a significant improvement in metabolic syndrome. However, very little is known about the underlying mechanism associated with significant weight loss post-surgery. Understanding such mechanisms could lead to development of safer non-surgical weight loss approaches. We here present the first analysis of the impact of LGP on the serum proteome, to bring new insights into the underlying molecular mechanism. Our findings indicate that LGP has a comprehensive systemic effect based on the blood serum proteome profile which might account for accelerated reduction of fat mass after surgery, thus, food restriction is not the only reason for weight loss following this unique surgical approach. As secretory regions of the stomach are preserved in LGP and it is associated with minimal physiological and anatomical changes, the findings are of high importance in the field of bariatric surgery and weight loss.

Increased levels of the novel hepatokine fetuin B in patients with intrahepatic cholestasis of pregnancy.

OBJECTIVES: To investigate liver-derived plasma protein fetuin B levels in healthy pregnant women and pregnant women with intrahepatic cholestasis of pregnancy (ICP). MATERIALS AND METHODS: Forty women with ICP and 40 healthy pregnant women were included in this cross-sectional study. The serum fetuin B levels of these patients were analyzed. The patients were followed up to delivery. RESULTS: Maternal age, gravida, parity, BMI at assessment, and gestational age at blood sampling were similar between the ICP and control groups (p > .05). However, the gestational age at delivery and the birth weight were significantly lower in the ICP group (p < .05). Total bile acid (TBA) levels and liver function tests were significantly higher in the ICP group than in the control group (p < .0001 and < .0001, respectively). In addition, serum fetuin B concentrations were significantly higher in the ICP group than in the control group (p < .0001). The best cutoff for fetuin B serum concentration was 5540.2 pg/mL. Serum values greater than this threshold had 80% sensitivity and 65% specificity for the diagnosis of ICP. CONCLUSIONS: Serum fetuin B was higher in patients with ICP compared to healthy pregnant women and might be a new biomarker.

Fetuin-B links nonalcoholic fatty liver disease to type 2 diabetes via inducing insulin resistance: Association and path analyses.

OBJECTIVE: Laboratory models suggested that Fetuin-B impaired insulin action in myotubes and hepatocytes and caused glucose intolerance in mice. We aimed to explore the independent associations and pathways among serum Fetuin-B, nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2D). METHODS: A cross-sectional study of 1318 obese adults who underwent serum Fetuin-B test and hepatic ultrasonography scanning was conducted in Xiamen, China. Multivariable logistic regression was used to calculate adjusted odds ratio (OR) and 95% confidence intervals (CI) of serum Fetuin-B level and NAFLD for T2D in different models with adjustment for potential confounders. Structural equation modeling (SEM) was used to examine the paths among NAFLD, serum Fetuin-B, metabolic/insulin resistance syndrome and T2D. RESULTS: Subjects with T2D or NAFLD showed significantly increased serum Fetuin-B levels compared to their controls (4.25 ±â€¯1.35 vs. 4.08 ±â€¯1.38 µg/ml for diabetes; and 4.26 ±â€¯1.41 vs. 4.07 ±â€¯1.33 µg/ml for NAFLD; both p-values < 0.05). NAFLD and higher serum Fetuin-B were significantly associated with higher risk of T2D with adjustment for sociodemographic and lifestyle habits; and the adjusted ORs (95%CIs) were 2.90 (2.17-3.87, p < 0.001) and 1.16 (1.01-1.32, p = 0.032), respectively. With further adjustment for metabolic/insulin resistance syndrome (BMI, systolic and diastolic BP, triglyceride, total cholesterol, HDL- and LDL-cholesterol, HOMA-IR and serum uric acid), NAFLD but not serum Fetuin-B was significantly associated with increased risk of T2D (ORs (95%CIs): 1.58 (1.12-2.21, p = 0.009) and 1.07 (0.92-1.23, p = 0.384), respectively). A one pathway model by using SEM fitted well (χ2 = 497.92, p < 0.001; CFI = 0.965; TLI = 0.926; and RMSEA = 0.097) and showed that NAFLD increased serum Fetuin-B and elevated Fetuin-B increased fasting insulin level, which in turn induced insulin resistance and T2D. Besides, NAFLD increased the risk of T2D directly in addition to its indirect effects of inducing metabolic/insulin resistance syndrome which in turn increased the risk of T2D. CONCLUSIONS: Fetuin-B links NAFLD to T2D via inducing insulin resistance, and NAFLD contributes to the pathogenesis of T2D via multiple mechanisms.

Plasma fetuin-B concentrations are associated with insulin resistance and first-phase glucose-stimulated insulin secretion in individuals with different degrees of glucose tolerance.

AIMS: To assess circulating fetuin-B concentrations in subjects with different degrees of glucose tolerance and to analyze the association of fetuin-B concentrations with insulin resistance and the first phase of glucose-stimulated insulin secretion. METHODS: Plasma fetuin-B concentrations were analyzed in 149 subjects with normal glucose tolerance (NGT, n=54), impaired glucose regulation (preDM, n=42) and newly diagnosed type-2 diabetes mellitus (nT2DM, n=53). Intravenous glucose tolerance tests (IVGTTs) and biochemical parameters were also assessed in all participants. RESULTS: Plasma fetuin-B concentrations were significantly higher in nT2DM patients compared with NGT and preDM subjects (both P<0.001) and positively correlated with FPG, 2hPG, HOMA-IR, HbA1c, hsCRP, FINS and TG (P<0.05), but negatively correlated with AIR, AUC, GDI and fasting Belfiore index (P<0.01). After adjusting for age and gender, all correlations remained statistically significant (P<0.05). Multivariate logistic regression analysis revealed that plasma fetuin-B concentrations were significantly correlated with nT2DM after controlling for age, gender, BMI, WHR, blood pressure and lipid profiles. CONCLUSION: Patients with nT2DM have significantly higher concentrations of plasma fetuin-B compared with NGT subjects and plasma fetuin-B is strongly associated with glucose and lipid metabolism, chronic inflammation and first-phase glucose-stimulated insulin secretion and insulin resistance.

Serum fetuin-B is positively associated with intrahepatic triglyceride content and increases the risk of insulin resistance in obese Chinese adults: A cross-sectional study.

BACKGROUND: Fetuin-B impairs insulin action in myotubes and hepatocytes and causes glucose intolerance in mice. This study explored the correlation between serum fetuin-B and intrahepatic triglyceride (IHTG) content, and the association between fetuin-B and the risk of insulin resistance in the general adult population. METHODS: A cross-sectional study of 1318 obese adults who underwent serum fetuin-B testing and hepatic ultrasonography was conducted in Xiamen, China. The IHTG content was determined in 428 subjects by magnetic resonance spectroscopy. RESULTS: Non-alcoholic fatty liver disease prevalence was significantly higher in those with the highest serum fetuin-B concentrations and the highest IHTC content (Tertile 3) than in subjects in Tertiles 1 and 2 (62.6% vs 60.7% and 54.3%, respectively [P = 0.032], and 15.3% vs 12.8% and 12.7%, respectively [P = 0.049]). There was a significant association between increasing serum fetuin-B tertiles and both increasing fasting insulin concentrations (mean [± SD] 11.9 ± 6.8, 12.7 ± 7.6, and 13.3 ± 6.4 mIU/L in Tertiles 1, 2 and 3, respectively; P = 0.006) and prevalence of insulin resistance (54.4%, 58.9%, and 64.5% in Tertiles 1, 2 and 3, respectively; P = 0.010). In linear regression analysis, IHTG content was independently and positively correlated with serum fetuin-B (regression coefficient 0.015; P = 0.045). With adjustment for potential confounders, serum fetuin-B was independently associated with increased risk of insulin resistance, with an adjusted odds ratio per standard deviation increase in fetuin-B of 1.14 (95% confidence interval 1.01-1.30; P = 0.031). CONCLUSIONS: The results demonstrate the role of fetuin-B linking liver fat accumulation to insulin resistance in humans.

The hepatokines fetuin-A and fetuin-B are upregulated in the state of hepatic steatosis and may differently impact on glucose homeostasis in humans.

The liver is a central regulator of whole body glucose, and lipid homeostasis and hepatokines, like fetuin-A, have been identified as markers and mediators of fatty liver-induced cardiometabolic risk. The closely related protein fetuin-B was shown to be upregulated in the fatty liver and to impact on glucose homeostasis in mice. In the present study we aimed to test the relevance of these findings in humans. In 55 subjects, hepatic mRNA expression of both hepatokines, fetuin-A and fetuin-B, associated positively with liver triglyceride content, whereas only fetuin-A expression associated with the homeostatic model assessment of insulin resistance. In 220 subjects who underwent precise metabolic phenotyping, circulating fetuin-A, but not fetuin-B, associated positively with liver fat content, and negatively with insulin sensitivity, measured during the oral glucose tolerance test (OGTT) and during the euglycemic, hyperinsulinemic clamp. Both circulating fetuin-A and fetuin-B correlated positively with the glucose area under the curve during the OGTT, but after additional adjustment for insulin sensitivity this relationship remained significant only for fetuin-B. In conclusion, despite the fact that the two hepatokines, fetuin-A and fetuin-B, are upregulated in the state of hepatic steatosis in humans, it appears that they differently impact on glucose homeostasis. Our data are in agreement with observations that fetuin-A can alter insulin signaling and that fetuin-B may regulate glucose homeostasis via so far unknown effects, possibly on glucose effectiveness.

[Correlation of fetuin-B concentrations in serum and follicular fluid with outcomes of in vitro fertilization].

OBJECTIVE: To investigate the relationship between serum/follicular fluid fetuin B levels and outcome of in vitro fertilization (IVF). METHODS: Infertility women (28 with low fertilization rates, 44 with normal fertilization rates) receiving IVF in Women's Hospital of Zhejiang University School of Medicine during June and December 2016 were enrolled in the study. Serum/follicular fluid fetuin B levels were measured with ELISA method. Correlations of serum and follicular fetuin B level with fertilization outcome of IVF were analyzed with Pearson correlation coefficient and receiver operating characteristic (ROC) curve. RESULTS: A positive correlation between serum fetuin B and follicular fluid fetuin B levels was observed (r=0.675, P<0.01). Both serum and follicular fluid fetuin B levels in women with low fertilization rates of IVF were lower than those in women with normal fertilization rates[(6.09±1.31) µg/mL vs. (7.13±1.47) µg/mL, t=3.050, P<0.05; (5.13±0.96)µg/mL vs. (6.22±1.33) µg/mL, t=3.755, P<0.01]. ROC analysis showed that the area under curve (AUC) of serum fetuin B level in predicting fertilization rate was 0.832 (95% CI:0.729-0.934, P<0.01), and 6.08 µg/mL could be used as cut-off value. CONCLUSIONS: Serum fetuin B level is correlated with follicular fluid fetuin B level, and it may be used for predicting the fertilization outcome of IVF.

Association of fetuin B with markers of liver fibrosis in nonalcoholic fatty liver disease.

OBJECTIVE: The liver-derived plasma protein fetuin B is associated with nonalcoholic fatty liver disease (NAFLD) and impaired glucose homeostasis in mice. However, its association with non-invasive ultrasound- and magnetic resonance (MR)-based markers of liver fibrosis and steatosis, the enhanced liver fibrosis (ELF) score, liver biopsy, as well as rs738409 in PNPLA3, has not been elucidated in NAFLD, so far. DESIGN AND METHODS: The association of circulating fetuin B and transient elastography (TE), controlled attenuation parameter (CAP), 1H-MR-spectroscopy, the ELF score, liver biopsy, as well as risk alleles in rs738409 in PNPLA3, was studied in 101 NAFLD patients as compared to 15 healthy controls. RESULTS: Serum fetuin B levels did not differ between NAFLD patients and controls (p = 0.863). Fetuin B was independently and negatively associated with transient elastography liver stiffness measurement (LSM) (p = 0.002), but not with the steatosis markers CAP or 1H-MR-spectroscopy. Fetuin B serum concentrations were significantly lower in individuals with LSM > 7.0 kPa as compared to patients with LSM < 7.0 kPa (p = 0.024). Furthermore, the ELF score and histologically proven fibrosis were independent and negative predictors of circulating fetuin B. Moreover, serum fetuin B significantly depended on number of rs738409 risk alleles (p = 0.026). CONCLUSIONS: Fetuin B is independently and negatively associated with non-invasive markers of liver fibrosis and PNPLA3 status in NAFLD patients but does not show a correlation with the hepatic lipid content. Future studies need to elucidate the pathophysiological significance of fetuin B in NAFLD and its potential value as predictor for disease severity.

Increased serum levels of fetuin B in patients with coronary artery disease.

BACKGROUND: Recent evidence indicates a pivotal role for fetuin B, one of the cystatin superfamily of cysteine protease inhibitors, in the pathogenesis of metabolic diseases. This study investigated whether serum fetuin B levels are associated with the presence of coronary artery disease. METHODS: Serum fetuin B levels were assessed in 87 patients with coronary artery disease (41 with acute coronary syndromes and 46 with stable angina pectoris) and 87 healthy controls using an enzyme-linked immunosorbent assay. The association of serum fetuin B levels with cardiac risk factors was analyzed. RESULTS: Serum fetuin B levels were significantly higher in patients with coronary artery disease than those in healthy controls (90.7 ± 32.1 vs. 110.0 ± 32.7 µg/ml, P < 0.001), extremely elevated in group with acute coronary syndromes (115.0 ± 35.2 µg/ml). Pearson correlation analysis showed that serum fetuin B levels were positively associated with the levels of total cholesterol (r = 0.276, P < 0.001), low-density lipoprotein cholesterol (r = 0.363, P < 0.001), and fasting blood glucose (r = 0.159, P < 0.05). In addition, multiple logistic regression analyses revealed that fetuin B was independently associated with the presence of coronary artery disease (OR, 1.019; 95% CI, 1.009 to 1.029; P < 0.001) and acute coronary syndromes (OR, 1.017; 95% CI, 1.006 to 1.028; P < 0.01). CONCLUSIONS: Our data revealed that high fetuin B levels are associated with the presence of coronary artery disease and acute coronary syndromes, and that fetuin B may serve as a potential biomarker for coronary artery disease.

Fetuin-B (FETUB): a Plasma Biomarker Candidate Related to the Severity of Lung Function in COPD.

Biomarkers for the progression of lung function in COPD are currently scarce. Plasma fetuin-B (FETUB) was identified by iTRAQ-based proteomics and was verified by ELISA in another group. Information regarding acute exacerbation (AE) was collected in a one-year follow-up programme. FETUB concentrations (1652 ± 427 ng/ml) were greater in COPD patients than in controls (1237 ± 77 ng/ml). The concentrations of FETUB in GOLD II (1762 ± 427 ng/ml), III (1650 ± 375 ng/ml) and IV (1800 ± 451 ng/ml) groups were greater than those in the controls (1257 ± 414 ng/ml) and the GOLD I (1345 ± 391 ng/ml) group. ROCs indicated that FETUB distinguished COPD patients from controls (AUC 0.747, 95% CI: 0.642-0.834) and also GOLD II, III and IV from GOLD I COPD patients (AUC: 0.770, 95% CI: 0.634-0.874). The combination of FETUB and fibrinogen performed better (AUC: 0.804, 95% CI: 0.705-0.881). FETUB also predicted the occurrence of AE (AUC: 0.707, 95% CI: 0.566-0.824) or frequent AE (AUC: 0.727, 95% CI: 0.587-0.840). FETUB concentrations were negatively correlated with FEV1%pred (r = -0.446, p = 0.000) and positively correlated with RV%pred (r = 0.317, p = 0.004), RV/TLC% (r = 0.360, p = 0.004), CT emphysema% (r = 0.322, p = 0.008) and grades of lung function (r = 0.437, p = 0.000). In conclusion, FETUB is likely to assist the diagnosis and management of COPD as a complement for other markers.

Toxicological effects of cationic nanobubbles on the liver and kidneys: biomarkers for predicting the risk.

Nanobubbles with acoustical activity are used as both diagnostic and therapeutic carriers for detecting and treating diseases. We aimed to prepare nanobubbles and assess toxic responses to them in the liver and kidneys. The cytotoxicity of nanobubbles was determined by examining the viability of liver (HepG2) and kidney (293T) cell lines after a 24-h treatment at various concentrations (0.01-2%). Toxic effects of different formulations were compared by determining functional markers such as γ-glutamyl transferase (γ-GT) and blood urea nitrogen (BUN) after intravenous administration of nanobubbles. Cationic nanobubbles caused concentration-dependent cytotoxicity against cultured cells with a more significant effect in the liver than in the kidneys. A significant reduction of viability was revealed at a concentration as low as 0.1%. Cational systems with soyaethyl morpholinium ethosulfate (SME) exhibited the greatest γ-GT level at 6-fold higher than the control. Immunohistochemistry detected liver fibrosis and inflammation with nanobubbles treatment, especially SME-containing ones at higher doses. According to plasma proteomic profiles, gelsolin and fetuin-B were significantly downregulated 3-fold in the high-dose SME-treated group. Transthyretin decreased by 6-fold in this group. The fibrinogen gamma chain expression was highly elevated. The results suggest that these protein biomarkers are sensitive for assessing the risk of nanobubble exposure. This study is the first to systematically evaluate the possible toxicity of nanobubbles in the liver and kidneys.