Correlation of serum Klotho, fetuin-A, and MGP levels with coronary artery calcification in maintenance hemodialysis patients.

OBJECTIVE: This study was to investigate the role of serum Klotho, fetuin-A, and Matrix Gla Protein (MGP) in Coronary Artery Calcification (CAC) in patients with Maintenance Hemodialysis (MHD) and their predictive value for CAC. METHODS: 100 patients receiving MHD were selected. Serum Klotho, fetuin-A, and MGP levels were detected by ELISA. CAC scores were assessed by coronary CT scan. Multifactor analysis was used to evaluate the risk factors affecting CAC. The ability of serum Klotho, fetuin-A, and MGP levels to diagnose CAC was evaluated by receiver operating characteristic curves. RESULTS: Serum Klotho, fetuin-A, and MGP were independent risk factors for CAC. Serum Klotho, fetuin-A, and MGP were valuable in the diagnosis of CAC in MHD patients. CONCLUSION: There is a close relationship between Klotho, fetuin-A, and MGP levels in MHD patients and CAC.

Fetuin-A: a relevant novel serum biomarker for non-invasive diagnosis of metabolic dysfunction-associated steatotic liver disease (MASLD): a retrospective case-control study.

OBJECTIVES: To determine how fetuin-A contributes to diagnosing and assessing MASLD severity. METHODS: Fifty MASLD patients and fifty healthy control participants were involved in this retrospective case-control research. Abdominal ultrasonography, fibroscan with controlled attenuated parameter scan (CAP scan), laboratory investigation (including fetuin-A assessment), clinical examination, and history-taking were performed on every case. RESULTS: Fetuin-A level was considerably higher in the Cases group (1154.85 ± 629.89) than in the Control group (505.29 ± 150.4) (p < 0.001). Fetuin-A had significant validity in the prediction of MASLD at a cut-off > 702.5 with 82% sensitivity, 90% specificity, and 86% overall accuracy. CONCLUSION: One possible marker for MASLD diagnosis could be fetuin-A. Furthermore, a substantial association between such marker and the severity of the disease as it revealed a significant correlation with ultrasound grading and fibroscan with controlled attenuated parameters. Trial registration 1- Pan African Clinical Trial Registry. Unique Identifying number/registration ID: PACTR202309644280965. URL: https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=26860 . Registration Approval date: 21/09/2023. 2- ClinicalTrials.gov. Unique Identifying number /registration ID: NCT06097039. URL: https://clinicaltrials.gov/study/NCT06097039?cond=NCT06097039&rank=1 . Registration Approval date: 25/10/2023.

Global O-glycoproteome enrichment and analysis enabled by a combinatorial enzymatic workflow.

A comprehensive analysis of site-specific protein O-glycosylation is hindered by the absence of a consensus O-glycosylation motif, the diversity of O-glycan structures, and the lack of a universal enzyme that cleaves attached O-glycans. Here, we report the development of a robust O-glycoproteomic workflow for analyzing complex biological samples by combining four different strategies: removal of N-glycans, complementary digestion using O-glycoprotease (IMPa) with/without another protease, glycopeptide enrichment, and mass spectrometry with fragmentation of glycopeptides using stepped collision energy. Using this workflow, we cataloged 474 O-glycopeptides on 189 O-glycosites derived from 79 O-glycoproteins from human plasma. These data revealed O-glycosylation of several abundant proteins that have not been previously reported. Because many of the proteins that contained unannotated O-glycosylation sites have been extensively studied, we wished to confirm glycosylation at these sites in a targeted fashion. Thus, we analyzed selected purified proteins (kininogen-1, fetuin-A, fibrinogen, apolipoprotein E, and plasminogen) in independent experiments and validated the previously unknown O-glycosites.

Apigenin targets fetuin-A to ameliorate obesity-induced insulin resistance.

Fetuin-A, a hepatokine secreted by hepatocytes, binds to insulin receptors and consequently impairs the activation of the insulin signaling pathway, leading to insulin resistance. Apigenin, a flavonoid isolated from plants, has beneficial effects on insulin resistance; however, its regulatory mechanisms are not fully understood. In the present study, we investigated the molecular mechanisms underlying the protective effects of apigenin on insulin resistance. In Huh7 cells, treatment with apigenin decreased the mRNA expression of fetuin-A by decreasing reactive oxygen species-mediated casein kinase 2α (CK2α)-nuclear factor kappa-light-chain-enhancer of activated B activation; besides, apigenin decreased the levels of CK2α-dependent fetuin-A phosphorylation and thus promoted fetuin-A degradation through the autophagic pathway, resulting in a decrease in the protein levels of fetuin-A. Moreover, apigenin prevented the formation of the fetuin-A-insulin receptor (IR) complex and thereby rescued the PA-induced impairment of the insulin signaling pathway, as evidenced by increased phosphorylation of IR substrate-1 and Akt, and translocation of glucose transporter 2 from the cytosol to the plasma membrane. Similar results were observed in the liver of HFD-fed mice treated with apigenin. Collectively, our findings revealed that apigenin ameliorates obesity-induced insulin resistance in the liver by targeting fetuin-A.

Vildagliptin inhibits high fat and fetuin-A mediated DPP-4 expression, intracellular lipid accumulation and improves insulin secretory defects in pancreatic beta cells.

Dipeptidyl peptidase-4 (DPP-4), a ubiquitous proteolytic enzyme, inhibits insulin secretion from pancreatic beta cells by inactivating circulating incretin hormones GLP-1 and GIP. High circulating levels of DPP-4 is presumed to compromise insulin secretion in people with type 2 diabetes (T2D). Our group recently reported lipid induced DPP-4 expression in pancreatic beta cells, mediated by the TLR4-NFkB pathway. In the present study, we looked at the role of Vildagliptin on pancreatic DPP-4 inhibition, preservation of islet mass and restoration of insulin secretion. MIN6 mouse insulinoma cells incubated with palmitate and fetuin-A, a proinflammatory organokine associated with insulin resistance, showed activation of TLR4-NFkB pathway, which was rescued on Vildagliptin treatment. In addition, Vildagliptin, by suppressing palmitate-fetuin-A mediated DPP-4 expression in MIN6, prevented the secretion of IL-1beta and fetuin-A in the culture media. DPP-4 siRNA abrogated TLR4-NFkB pathway mediated islet cell inflammation. Vildagliptin also reduced palmitate-fetuin-A mediated intracellular lipid accumulation in MIN6 and isolated islets from high fat fed (HFD) mice as observed by Oil O Red staining with downregulation of CD36 and PPARgamma. Vildagliptin also preserved islet mass and rescued insulin secretory defect in HFD mice. Our results suggest that inhibition of DPP-4 by Vildagliptin protects pancreatic beta cells from the deleterious effects of lipid and fetuin-A, preserves insulin secretory functions and improves hyperglycemia.

Does fetuin-A mediate the association between pro-inflammatory diet and type-2 diabetes mellitus risk? / ¿Fetuína-A media en la asociación entre la dieta proinflamatoria y el riesgo de diabetes mellitus tipo 2?

Introduction: recent studies indicate that diet increases T2DM risk via inflammation. Fetuin-A, identified as an acute-phase protein, plays a role in insulin resistance and is an independent predictor of type-2 diabetes. Objectives: the present study aimed to examine the association between diet and T2DM risk, and whether said association is mediated by fetuin-A, and to determine the effect of fetuin-A on T2DM risk. Methods: the case group included 40 individuals with T2DM, whereas 40 individuals without T2DM comprised the control group. The Dietary Inflammatory Index (DII), was used to determine the inflammatory potential of diet. A simple mediation analysis was used to investigate whether diet was associated with T2DM risk and whether the association was mediated by fetuin-A. Results: subjects who consumed a high pro-inflammatory diet had 2.0 times higher risk of developing T2DM (OR = 2.043; 95 % CI: 0.955 to 4.371, p = 0.066). In addition, subjects who had higher levels of fetuin-A had a 1,2 times higher risk of developing T2DM (OR = 1.155; 95 % CI: 1.030 to 1.296, p = 0.014). Both fetuin-A and hs-CRP had a significant full mediator role on the association between DII and HOMA-IR [respectively; β = 0.371 (95 % CI: -0.029-0.770), β = 0.424 (95 % CI: -0.007-0.856)]. Conclusion: these findings suggest that a pro-inflammatory diet, by creating an environment of increased inflammatory markers, affects in particular insulin resistance through these markers and ultimately causes T2DM. In addition, fetuin-A also acts as an important novel mediator between diet and T2DM by inducing insulin resistance (AU)

Introducción: estudios recientes indican que la dieta aumenta el riesgo de T2DM mediante la inflamación. La fetuína-A,identificada como proteína de fase aguda, desempeña un papel en la resistencia a la insulina y es un predictor independiente de la diabetes de tipo 2. Objetivos: el presente estudio pretende examinar la asociación entre la dieta y el riesgo de DMT2 y si la asociación está mediada por la fetuína-A y determinar el efecto de la fetuína-A sobre el riesgo de DMT2. Métodos: en el grupo de casos se incluyeron 40 individuos con DMT2, mientras que 40 individuos sin DMT2 se incluyeron en el grupo de control. El índice de inflamación de la dieta (DII) se usó para determinar el potencial inflamatorio de la dieta. El análisis de mediación simple se usó para investigar si la dieta estaba asociada con el riesgo de DMT2 y si la asociación estaba mediada por la fetuína-A. Resultados: los sujetos que consumieron una dieta más proinflamatoria tuvieron 2 veces más riesgo de desarrollar DMT2. Además, los sujetos que tenían niveles más altos de fetuína-A tuvieron 1,2 veces más riesgo de desarrollar DMT2. Tanto la fetuína-Acomo la hs-CRP tuvieron un papel significativo como mediadores completos sobre la asociación entre DII y HOMA-IR. Conclusión: estos hallazgos sugieren que la dieta proinflamatoria, al crear un ambiente con marcadores inflamatorios aumentados, afecta en particular a la resistencia a la insulina a través de estos marcadores y, finalmente, causa DMT2. Además, la fetuína-A también actúa como mediador novedoso importante entre la dieta y la DMT2 al inducir la resistencia a la insulina (AU)

Effects of Lowering Dialysate Calcium Concentrations on Arterial Stiffness in Patients Undergoing Hemodialysis

BACKGROUND/AIMS: We assessed changes in hemodynamic and arterial stiffness parameters following reductions of dialysate calcium concentrations in patients undergoing hemodialysis. METHODS: In this prospective study, 20 patients on maintenance hemodialysis (10 females, 10 males) with dialysate calcium concentrations of 1.75 mmol/L were enrolled. At the start of the study, the dialysate calcium level was lowered to 1.50 mmol/L. Serial changes in biochemical, hemodynamic, and arterial stiffness parameters, including pulse wave velocity (PWV) and augmentation index (AIx), were assessed every 2 months for 6 months. We also examined changes in the calcification-inhibitory protein, serum fetuin-A. RESULTS: During the 6-month study period, serum total calcium and ionized calcium decreased consistently (9.5 +/- 1.0 to 9.0 +/- 0.7, p = 0.002 vs. 1.3 +/- 0.1 to 1.1 +/- 0.1, p = 0.035). Although no apparent changes in blood pressure were observed, heart-femoral PWW (hf-PWV) and AIx showed significant improvement (p = 0.012, 0.043, respectively). Repeated-measures ANOVA indicated a significant effect of lowering dialysate calcium on hf-PWV (F = 4.58, p = 0.004) and AIx (F = 2.55, p = 0.049). Accompanying the change in serum calcium, serum fetuin-A levels significantly increased (95.8 +/- 45.8 pmol/mL at baseline to 124.9 +/- 82.2 pmol/mL at 6 months, p = 0.043). CONCLUSIONS: Lowering dialysate calcium concentration significantly improved arterial stiffness parameters, which may have been associated with upregulation of serum fetuin-A.

Discovery of the serum biomarker proteins in severe preeclampsia by proteomic analysis

Preeclapsia (PE) is a severe disorder that occurs during pregnancy, leading to maternal and fetal morbidity and mortality. PE affects about 3-8% of all pregnancies. In this study, we conducted liquid chromatographymass spectrometry/mass spectrometry (LC-MS/MS) to analyze serum samples depleted of the six most abundant proteins from normal and PE-affected pregnancies to profile serum proteins. A total of 237 proteins were confidently identified with < 1% false discovery rate from the two groups of duplicate analysis. The expression levels of those identified proteins were compared semiquantitatively by spectral counting. To further validate the candidate proteins with a quantitative mass spectrometric method, selective reaction monitoring (SRM) and enzyme linked immune assay (ELISA) of serum samples collected from pregnant women with severe PE (n = 8) or normal pregnant women (n = 5) was conducted. alpha2-HS-glycoprotein (AHSG), retinol binding protein 4 (RBP4) and alpha-1-microglobulin/bikunin (AMBP) and Insulin like growth factor binding protein, acid labile subunit (IGFBP-ALS) were confirmed to be differentially expressed in PE using SRM (P < 0.05). Among these proteins, AHSG was verified by ELISA and showed a statistically significant increase in PE samples when compared to controls.