Plasma fetuin-A concentrations in young and older high- and low-active men

Impacts of an 8-week regimen of aged garlic extract and aerobic exercise on the levels of Fetuin-A and inflammatory markers in the liver and visceral fat tissue of obese male rats

BACKGROUND & AIMS

Obesity-induced chronic low-grade systemic inflammation is linked to the development of numerous diseases. Fetuin-A is known to affect inflammation and insulin resistance in obesity conditions. Free fatty acid (FFA)-induced proinflammatory cytokine expression in adipocytes occurs only in the presence of both Fetuin-A and toll-like receptor 4 (TLR4) and removing either of them prevented FFA-induced insulin resistance. Aged garlic extract (AGE) and exercise training have anti-inflammatory effects; however, the impact of AGE on Fetuin-A is unknown. We examined the effects of AGE with or without aerobic training (AT) on Fetuin-A and inflammatory markers.

METHODS

Forty healthy male Sprague Dawley rats were randomly assigned to normal diet (ND) (n = 8) or high-fat diet (HFD) groups (n = 32) and fed for 9 weeks. After 9 weeks ND group continued normal diet, and the HFD group was randomly assigned to the HFD, HFD + AGE (600 mg/kg, once daily), HFD + AT (5 days/week), and HFD + AGE + AT groups that were continued for 8 weeks (n = 8). The significance of differences among groups was assessed using one-way analysis of variance followed by the post-hoc Tukey test. Statistically significant differences were considered for p < 0.05.

RESULTS

AGE, AT, and AGE + AT significantly decreased body weight, plasma Fetuin-A, HOMA-IR, mRNA and protein levels of Fetuin-A and NFƙB in the liver and mRNA and Protein levels of Fetuin-A, TLR4 and NFƙB in visceral adipose tissue (VAT) compared to HFD. However, only AGE + AT significantly decreased TLR4 protein levels in the liver.

CONCLUSION

Although AT and AGE reduce Fetuin-A and inflammatory markers, a combination of the two may be more effective at lowering inflammation.

Liver Fetuin-A at Initiation of Insulin Resistance

Hepatokines (liver secreted proteins with possible distant action) are emerging potential players in insulin resistance in type 2 diabetic patients. Here, we explored the effect of a high-fat diet on the expression of fetuin-A, one of those candidate liver proteins, and its relationship with liver macrophage activation. Mice were fed a normal diet or a high-fat diet for 3 days, known to initiate steatosis and liver insulin resistance. A preventive liver macrophage depletion was obtained by intravenous injection of clodronate-loaded liposomes. The mRNA and protein expression of fetuin-A was evaluated by qPCR, Western blot and immunofluorescence on different insulin-sensitive tissues (liver, adipose tissue, and muscle). Short-term high-fat diet-induced steatosis, liver macrophage activation, and hepatic insulin resistance together with a significantly increased expression of liver AHSG (α2-HS glycoprotein/fetuin-A) mRNA and serum fetuin-A concentration. On immunofluorescence, fetuin-A was mostly expressed in centrilobular hepatocytes. This increase in fetuin-A under high-fat diet was not evidenced in other peripheral insulin-sensitive tissues (skeletal muscle and adipose tissue). The mRNA expression of α2-HS glycoprotein was 800 times higher within the liver compared with the adipose tissue or the muscle. Liver macrophage depletion that significantly ameliorated insulin sensitivity was associated with a significant decrease in α2-HS glycoprotein mRNA expression. In conclusion, this study demonstrated liver fetuin-A overexpression at the initiation of high-fat diet feeding, concurrent with hepatic steatosis and insulin resistance. Targeting liver macrophages in this setting reduced liver α2-HS glycoprotein expression suggesting that fetuin-A acts as an hepatokine with proinsulin resistance effects.

Comparative Proteomic Assessment of Normal vs. Polyhydramnios Amniotic Fluid Based on Computational Analysis

Mass spectrometry-based proteomics have become a valued tool for conducting comprehensive analyses in amniotic fluid samples with pathologies. Our research interest is the finding and characterization of proteins related to normal vs. polyhydramnios (non-immune hydrops) pregnancy. Proteomic analysis was performed on proteins isolated from fresh amniotic fluid samples. Proteins were fractionated by 2DE using a different pI range (pI 3–11, pI 4–7) and analyzed with MALDI-TOF-MS. Furthermore, by using computational analysis, identified proteins in protein maps specific to normal vs. polyhydramnios pregnancy were compared and the quantities of expressed proteins were evaluated mathematically. Comparative analysis of proteome characteristic for the same polyhydramnios pregnancy fractionated by 2DE in different pI range (3–11 and 4–7) was performed and particular protein groups were evaluated for the quantification of changes within the same protein level. Proteins of normal and polyhydramnios pregnancies were fractionated by 2DE in pI range 3–11 and in pI range 4–7. Mass spectrometry analysis of proteins has revealed that the quantity changes of the main identified proteins in normal vs. polyhydramnios pregnancy could be assigned to immune response and inflammation proteins, cellular signaling and regulation proteins, metabolic proteins, etc. Specifically, we have identified and characterized proteins associated with heart function and circulatory system and proteins associated with abnormalities in prenatal medicine. The following are: serotransferrin, prothrombin, haptoglobin, transthyretin, alpha-1-antitrypsin, zinc-alpha-2-glycprotein, haptoglobin kininogen-1, hemopexin, clusterin, lumican, afamin, gelsolin. By using computational analysis, we demonstrated that some of these proteins increased a few times in pathological pregnancy. Computer assistance analysis of 2DE images suggested that, for the better isolation of the proteins’ isoforms, those levels increased/decreased in normal vs. polyhydramnios pregnancy, and the fractionation of proteins in pI rage 3–11 and 4–7 could be substantial. We analyzed and identified by MS proteins specific for normal and polyhydramnios pregnancies. Identified protein levels increased and/or modification changed in case of non-immune hydrops fetus and in cases of cardiovascular, anemia, growth restriction, and metabolic disorders. Computational analysis for proteomic characterization empower to estimate the quantitative changes of proteins specific for normal vs. polyhydramnios pregnancies.

Serum fetuin-A and Ser312 phosphorylated fetuin-A responses and markers of insulin sensitivity after a single bout of moderate intensity exercise

Fetuin‐A (Fet‐A), secreted by the liver and adipose tissue, inhibits insulin receptor tyrosine kinase activity and modulates insulin action. Numerous studies have shown association of elevated serum Fet‐A concentrations with obesity, non‐alcoholic fatty liver disease, and type 2 diabetes. Both moderate body weight loss (5%–10%) and significant body weight loss have been shown to decrease serum Fet‐A and improve insulin sensitivity. Currently, there are no studies examining the effects of a single bout of exercise on serum Fet‐A or Ser312‐pFet‐A (pFet‐A) responses. We hypothesized that a single bout of moderate‐intensity exercise will lower serum Fet‐A and that these changes will be associated with an improvement in insulin sensitivity. Thirty‐one individuals with obesity and 11 individuals with normal body weight were recruited. Participants underwent a single bout of treadmill walking, expending 500 kcal at 60%–70% VO_2max. Oral glucose tolerance tests (OGTT) were administered before the single bout of exercise (Pre Ex) and 24 h after exercise (24h Post Ex). In individuals with obesity, we observed a transient elevation of serum Fet‐A concentrations, but not pFet‐A, immediately after exercise (Post Ex). Further, a single bout of exercise decreased glucose_AUC, insulin_AUC, and insulin resistance index in individuals with obesity. Consistent with this improvement in insulin sensitivity, we observed that Fet‐A_AUC, pFet‐A_AUC, 2 h pFet‐A, and 2 h pFet‐A/Fet‐A were significantly lower following a single bout of exercise. Further, reductions in serum Fet‐A_AUC 24h Post Ex were correlated with a reduction in insulin resistance index. Together, this suggests that alterations in serum Fet‐A following a single bout of moderate‐intensity endurance exercise may play a role in the improvement of insulin sensitivity.

Clinical Trial Registration

NCT03478046; https://clinicaltrials.gov/ct2/show/NCT03478046.

Glioblastoma: Is There Any Blood Biomarker with True Clinical Relevance?

Glioblastoma (GBM) is the most frequent malignant primary brain tumor in adults, characterized by a highly aggressive, inflammatory and angiogenic phenotype. It is a remarkably heterogeneous tumor at several levels, including histopathologically, radiographically and genetically. The 2016 update of the WHO Classification of Tumours of the Central Nervous System highlighted molecular parameters as paramount features for the diagnosis, namely IDH1/2 mutations that distinguish primary and secondary GBM. An ideal biomarker is a molecule that can be detected/quantified through simple non- or minimally invasive methods with the potential to assess cancer risk; promote early diagnosis; increase grading accuracy; and monitor disease evolution and treatment response, as well as fundamentally being restricted to one aspect. Blood-based biomarkers are particularly attractive due to their easy access and have been widely used for various cancer types. A number of serum biomarkers with multiple utilities for glioma have been reported that could classify glioma grades more precisely and provide prognostic value among these patients. At present, screening for gliomas has no clinical relevance. This is because of the low incidence, the lack of sensitive biomarkers in plasma, and the observation that gliomas may develop apparently de novo within few weeks or months. To the best of our knowledge, there is no routine use of a serum biomarker for clinical follow-up. The purpose of this paper is to review the serum biomarkers described in the literature related to glioblastoma and their possible relationship with clinical features.

Effects of exercise training on Fetuin-a in obese, type 2 diabetes and cardiovascular disease in adults and elderly: a systematic review and Meta-analysis

Background

Elevated levels of fetuin-A are associated with increased risks of metabolic syndrome, type 2 diabetes and nonalcoholic fatty liver disease. This meta-analysis investigated whether exercise interventions can reduce fetuin-A in adults.

Methods

We searched clinical trials that objectively assessed fetuin-A and included study arms with exercise intervention. The pre-intervention and post-intervention data were used for meta-analysis. The effect sizes were calculated as standardized mean differences or changes in fetuin-A and expressed as Hedges’ g using random-effects models.

Results

The overall Hedges’ g for fetuin-A in all included interventions was − 0.640 (95%CI − 1.129 to − 0.151; n = 9), but this effect was not observed in obese (g = − 0.096; 95%CI, − 0.328 to 0.135) and type 2 diabetes/dysglycemia (g = − 0.56; 95%CI, − 1.348 to 0.236) individuals. Additionally, the random-effects meta-regression analysis showed that there was not a greater decrease in fetuin-A in individuals who achieved greater body mass index reductions (regression coefficient = 0.065; 95%CI, − 0.185 to 0.315).

Conclusion

Supervised exercise is associated with reductions in fetuin-A levels in adults and elderly. However, the results of the present meta-analysis should be interpreted with caution because of the variety of type of exercises and individual obesity related-disorders involve. Therefore, additional high-quality randomized controlled trials describing the effect of supervised exercise interventions on fetuin-A in adults are still needed. 

Electronic supplementary material

The online version of this article (10.1186/s12944-019-0962-2) contains supplementary material, which is available to authorized users.

The association between fetuin-A and testosterone levels and markers of arterial stiffness in Saudi subjects with type 2 diabetes mellitus

BACKGROUND

Inconsistent results have been described regarding the part of fetuin-A and testosterone in arterial stiffness in type 2 diabetes mellitus (T2DM).

AIM

To look into the links of serum fetuin-A and testosterone levels with brachial-Ankle pulse wave velocity (baPWV), a marker of arteriosclerosis and common carotid intima media thickness (ccIMT), a marker of early atherosclerosis, in diabetic Saudi men patients.

SUBJECTS AND METHODS

One hundred and fifty adult male patients with T2DM and 60 non-diabetic control subjects were enrolled from different Saudi Arabia Taif hospitals. Biochemical analysis, anthropometric measurements, blood pressure, baPWV and ccIMT were investigated.

RESULTS

Stepwise regression in diabetic patients revealed that the most important predictor of ba-PWV was serum fetuin-A followed by serum glucose and the most important predictor of ccIMT was serum fetuin-A followed by serum HDL then serum triglycerides.

CONCLUSIONS

Only fetuin-A levels not testosterone are negatively associated with early markers of atherosclerosis.

The association between circulating fetuin-A levels and type 2 diabetes mellitus risk: systematic review and meta-analysis of observational studies

BACKGROUND AND OBJECTIVE

Fetuin-A is a liver-derived circulating protein that is associated with insulin resistance and diabetes. The objective of this systematic review and meta-analysis of published observational studies was to investigate mean levels of fetuin-A in T2D patients and the relationship between blood fetuin-A levels and T2D risk.

MATERIALS AND METHODS

PubMed, Embase, Google Scholar, Web of Science, and The Cochrane Library were systematically searched for potential relevant studies up to 1 December 2016. Natural logarithm-transformed estimate risks, standard mean differences on the basis of Hedges's adjusted g, and 95% confidence intervals (CIs) were calculated for all eligible studies and were combined to measure the pooled data using random-effects model.

RESULTS

A total of 32 studies including 27 case-control and 5 cohort studies were included in the current study. Fetuin-A levels in T2D patients were significantly higher than control groups [Hedges' g = 1.73, 95% CI (1.25-2.22), P < 0.001], with significant heterogeneity across studies (P < 0.001, I ² = 98.46%). Findings from meta-analyses of cohort studies showed a statistically significant association between fetuin-A levels and T2D risk [rate ratio = 1.62, 95% CI (1.26-2.08), P < 0.001], with no significant heterogeneity (P = 0.10, I ² = 46.06%).

CONCLUSION

We found a significant relationship between the fetuin-A levels with T2D risk. Although fetuin-A may be as a potential screening and prediction biomarker or a therapeutic target in T2D patients, further studies are required in this regard.

Fetuin-A: A negative acute-phase protein linked to adipose tissue function in periparturient dairy cows

Fetuin-A (FetA) is a free fatty acid transporter and an acute-phase protein that enhances cellular lipid uptake and lipogenesis. In nonruminants, FetA is involved in lipid-induced inflammation. Despite FetA importance in lipid metabolism and inflammation, its expression and dynamics in adipose tissue (AT) of dairy cows are unknown. The objectives of this study were to (1) determine serum and AT FetA dynamics over the periparturient period and in mid-lactation cows in negative energy balance (NEB) after a feed restriction protocol and (2) characterize how an inflammatory challenge affects adipocyte FetA expression. Blood and subcutaneous AT were collected from 16 cows with high (≥3.75, n = 8) or moderate (≤3.5, n = 8) body condition score (BCS) at -26 ± 7 d (far off) and -8 ± 5 d (close up) before calving and at 10 ± 2 d after parturition (early lactation) and from 14 nonpregnant mid-lactation cows (>220 d in milk) after a feed restriction protocol. Serum FetA concentrations were 0.89 ± 0.13 mg/mL at far off, 0.96 ± 0.13 mg/mL at close up, and 0.77 ± 0.13 mg/mL at early lactation and were 1.09 ± 0.09 and 1.17 ± 0.09 mg/mL in feed-restricted and control cows, respectively. Serum and AT FetA contents decreased at the onset of lactation when lipolysis was higher. No changes in AT and serum FetA were observed after feed restriction induced NEB in mid-lactation cows. Prepartum BCS had no effect on serum FetA, but AT expression of AHSG, the gene encoding FetA, was reduced in periparturient cows with high BCS at dry-off throughout all time points. Circulating FetA was positively associated with serum albumin and calcium and with BCS variation over the periparturient period. The dynamics of AHSG expression were analogous to the patterns of lipogenic markers ABDH5, ELOVL6, FABP4, FASN, PPARγ, and SCD1. Expression of AHSG and FetA protein in AT was inversely correlated with AT proinflammatory markers CD68, CD44, SPP1, and CCL2. In vitro, bovine adipocytes challenged with lipopolysaccharide downregulated FetA protein expression. Adipocytes treated with FetA had lower CCL2 expression compared with those exposed to lipopolysaccharide. Overall, FetA is a systemic and local AT negative acute-phase protein linked to AT function in periparturient cows. Furthermore, FetA may support physiological adaptations to NEB in periparturient cows.

Emerging Human Fetuin A Assays for Biomedical Diagnostics

Human fetuin A (HFA) plays a prominent pathophysiological role in numerous diseases and pathophysiological conditions with considerable biomedical significance; one example is the formation of calciprotein particles in osteoporosis and impaired calcium metabolisms. With impressive advances in in vitro diagnostic assays during the last decade, ELISAs have become a workhorse in routine clinical diagnostics. Recent diagnostic formats involve high-sensitivity immunoassay procedures, surface plasmon resonance, rapid immunoassay chemistries, signal enhancement, and smartphone detection. The current trend is toward fully integrated lab-on-chip platforms with smartphone readouts, enabling health-care practitioners and even patients to monitor pathological changes in biomarker levels. This review provides a critical analysis of advances made in HFA assays along with the challenges and future prospects.

Exercise-induced lowering of fetuin-A may increase hepatic insulin sensitivity

INTRODUCTION

Fetuin-A is a novel hepatokine, and there is preliminary evidence that it may contribute to the pathogenesis of type 2 diabetes. Exercise reduces fetuin-A, but the specific metabolic effects particularly as they relate to the regulation of insulin resistance are unknown. This led us to examine the effect of exercise training on circulating fetuin-A in relation to skeletal muscle and/or hepatic insulin resistance in obese adults.

METHODS

Twenty older adults (66.3 ± 0.9 yr; body mass index, 34.1 ± 1.2 kg · m(-1)) participated in this prospective 12-wk study and underwent supervised exercise training (5 d · wk(-1), 60 min · d(-1) at approximately 85% HRmax). Insulin resistance was assessed using the euglycemic-hyperinsulinemic clamp (40 mU · m(-2) · min(-1)) with isotope dilution ([6,6-H2]-glucose). Skeletal muscle insulin sensitivity (rate of glucose disposal), hepatic insulin resistance (rate of glucose appearance × fasting insulin), metabolic flexibility (respiratory quotient clamp - respiratory quotient fasting), fetuin-A, high-molecular weight adiponectin, high-sensitivity C-reactive protein, leptin, and body fat (dual energy x-ray absorptiometry) were measured before and after the intervention.

RESULTS

Exercise reduced body fat, high-sensitivity C-reactive protein, leptin and hepatic as well as skeletal muscle insulin resistance (each, P < 0.05). Fetuin-A was decreased by approximately 8% (pre, 1.01 ± 0.08, vs post, 0.89 ± 0.06 g · L(-1); P < 0.05) after the intervention, and lower fetuin-A after exercise correlated with lower hepatic insulin resistance (r = -0.46, P < 0.01), increased metabolic flexibility (r = -0.70, P < 0.01) and high-molecular weight adiponectin (r = -0.57, P < 0.01).

CONCLUSIONS

Fetuin-A may contribute to exercise training-induced improvements in hepatic insulin resistance, CHO utilization, and inflammation in older obese adults. Further work is required to determine the cellular mechanism(s) of action for fetuin-A because this hepatokine is related to type 2 diabetes risk.

Circulating alanine transaminase (ALT) and γ-glutamyl transferase (GGT), but not fetuin-A, are associated with metabolic risk factors, at baseline and at two-year follow-up: the prospective Cyprus Metabolism Study

OBJECTIVE

To comparatively evaluate traditional liver tests and fetuin A as predictors of cardiometabolic risk, we studied associations between serum alanine transaminase (ALT), γ-glutamyl transferase (GGT), aspartate aminotransferase (AST) and fetuin-A and anthropometric, metabolic, and cardiovascular parameters cross-sectionally at baseline, and prospectively, after 2-years of follow-up.

RESEARCH DESIGN AND METHODS

616 randomly enrolled young healthy participants in the Cyprus Metabolism Study, including all 93 subjects who participated in the follow-up study 2 years after baseline assessment, were included in this study.

RESULTS

In the cross-sectional study, serum ALT and GGT were strongly correlated with anthropometric, cardiovascular, and metabolic variables, while serum AST was only correlated with waist circumference and waist-to-hip ratio. Fetuin-A was correlated with anthropometric variables, systolic blood pressure (SBP), insulin, and homeostasis model of assessment-insulin resistance (HOMA-IR) in the unadjusted model. In the fully adjusted model, both serum ALT and GGT levels remained positively correlated with total and low-density lipoprotein (LDL) cholesterol. GGT levels also remained correlated with triglycerides. ALT levels remained strongly positively correlated with insulin (r=0.17, p<.0001) and HOMA-IR (r=0.16, p=0.0001). Serum fetuin-A levels were no longer significantly correlated with any variables. Prospectively, ALT and GGT were predictors of anthropometric variables and LDL cholesterol, while baseline levels of AST and fetuin-A were not predictors of any variables at 2-year follow-up.

CONCLUSIONS

We confirmed associations of ALT and GGT levels but failed to demonstrate an independent association between fetuin-A and cardiometabolic risk factors in young healthy men. Traditional liver tests (LFTs) are thus better than fetuin-A predictors of metabolic risk factors cross-sectionally and prospectively in young healthy adults.

AMP-activated Protein Kinase (AMPK): Does This Master Regulator of Cellular Energy State Distinguish Insulin Sensitive from Insulin Resistant Obesity?

Although a correlation exists between obesity and insulin resistance, roughly 25 % of obese individuals are insulin sensitive. AMP-activated protein kinase (AMPK) is a cellular energy sensor that among its many actions, integrates diverse physiological signals to restore energy balance. In addition, in many situations it also increases insulin sensitivity. In this context, AMPK activity is decreased in very obese individuals undergoing bariatric surgery who are insulin resistant compared to equally obese patients who are insulin sensitive. In this review, we will both explore what distinguishes these individuals, and evaluate the evidence that diminished AMPK is associated with insulin resistance and metabolic syndrome-associated disorders in other circumstances.

Fetuin-A is linked to improved glucose tolerance after short-term exercise training in nonalcoholic fatty liver disease

Fetuin-A is synthesized in the liver and may be associated with nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes. Lifestyle-induced weight loss reduces fetuin-A, but the effect of exercise alone is unknown. We determined the effect of short-term exercise training on plasma fetuin-A in 13 (50.5 ± 3.4 yr) obese adults (body mass index, 33.3 ± 0.9 kg/m(2)) with clinically diagnosed NAFLD. Subjects participated in 7 days of supervised exercise training (60 min/day at ∼85% maximum heart rate) and were instructed to maintain their normal caloric and macronutrient intake. Insulin resistance was assessed by an oral glucose tolerance test. Hepatic triglyceride content (HTGC) was determined by proton MRI. We used C2C12 skeletal muscle cells to examine the direct effect of fetuin-A on 2-deoxyglucose uptake, insulin signaling [phosphorylation of Akt and AS160 (pAkt and pAS160, respectively)], and glucose transporter-4 (GLUT-4) translocation. Insulin resistance was reduced by 29% (P < 0.05), and glucose area under the curve (AUC) was decreased by 13% (P < 0.01) after the 7 days of exercise. Furthermore, circulating fetuin-A was decreased by 11% (4.2 ± 03 vs. 3.6 ± 0.2 nM; P < 0.02), and this change correlated with reduced insulin resistance (r = 0.62; P < 0.04) and glucose AUC (r = 0.58; P < 0.04). Importantly, the exercise program did not change body weight (P = 0.12), HTGC (P = 0.73), or aerobic capacity (P = 0.14). In vitro experiments revealed that fetuin-A decreased skeletal muscle glucose uptake by downregulating pAkt and pAS160 and subsequent GLUT-4 translocation to the plasma membrane. Together, our findings highlight a role for fetuin-A in skeletal muscle insulin resistance and suggest that part of the exercise-induced improvement in glucose tolerance in patients with NAFLD may be due to lowering fetuin-A.

Fetuin-A and angiopoietins in obesity and type 2 diabetes mellitus

Although type 2 diabetes mellitus (DM) is a chronic metabolic disorder with multiple etiologies, obesity has been constantly linked with insulin resistance and manifestation of type 2 DM. In addition, obesity is associated with hypertension, dyslipidemia, and fatty liver disease and is regarded as a subclinical inflammatory condition characterized by release of pro-inflammatory mediators such as cytokines from adipose tissue. Both, type 2 DM and obesity are considered as major risks for developing micro- and macrovascular diseases. Recent studies showed that impaired circulating levels of fetuin-A, which is involved in propagating insulin resistance as well as circulating levels of angiopoietins, which are growth factors promoting angiogenesis, were observed in patients with obesity, metabolic syndrome, and type 2 DM. However, independent of type 2 DM and obesity, defective regulation of fetuin-A and angiopoietin are playing a critical role in predisposing to coronary and peripheral vascular diseases. Therefore, mechanisms linking type 2 DM and obesity with fetuin-A and angiopoietins seem to be complex and are in need of further exploration. In this review, we aimed to present a summary concerning associations of type 2 diabetes, obesity, and vascular diseases with circulating levels of angiopoietins and fetuin-A. Furthermore, we aimed to focus on roles of fetuin-A and angiopoietins and to highlight the most plausible mechanisms that might explain their associations with type 2 DM and obesity.

Fetuin A concentration in the second trimester amniotic fluid of fetuses with trisomy 21 appears to be lower: phenotypic considerations

OBJECTIVE

We investigated whether the concentration of the glycoprotein fetuin A is altered in the second trimester amniotic fluid of trisomy 21 pregnancies compared with euploid pregnancies.

METHODS

25 pregnancies with an extra chromosome 21 were matched for maternal and gestational age with 25 pregnancies with normal karyotype. Levels of fetuin A in amniotic fluid were measured by a commercially available enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

The median concentration of fetuin A in amniotic fluid of trisomy 21 pregnancies (5.3 ng/ml) was statistically significantly lower (P value = 0.008) compared with that in euploid pregnancies (6.8 ng/mL).

CONCLUSION

Lower levels of fetuin A in trisomy 21 may indicate an association with altered metabolic pathways in this early stage that could potentially be associated with features of the syndrome, such as growth restriction or impaired osteogenesis.

Age, weight and obesity

The western world is facing the consequences of higher standards of medical care and improved living conditions. While people are living longer the prevalence of overweight and obesity is escalating which increases the risk of developing non-communicable diseases. However it must be noted that there is a U shaped relationship between weight and mortality with both under and overweight increasing risk. This review examines possible contributory factors for overweight and obesity in older people: life style, depression, changes in body composition, endocrine alterations, sympathetic tone, oxidative stress and concomitant disease.

Age-related modification of antioxidant enzyme activities in relation to cardiovascular risk factors

BACKGROUND

Since oxidative stress might cause and promote cardiovascular risk factors such as oxidized low-density lipoproteins (oxLDL), apolipoprotein(a) [apo(a)], asymmetric dimethylarginine (ADMA) and fetuin A, we investigated antioxidant enzyme activities in relation to the vascular redox balance and these risk factors in elderly people.

MATERIALS AND METHODS

For this observational study, a total of 102 subjects were recruited and divided into three groups: A (70-74 years/n = 48), B (75-79 years/n = 35) and C (≥ 80 years/n = 19). Activities of the erythrocyte antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were determined photometrically oxLDL, apo(a), ADMA and fetuin A by ELISA. Plasma concentrations of the lipid peroxidation products malondialdehyde (MDA) and conjugated dienes (CD) were analysed with HPLC.

RESULTS

There were no significant age-associated alterations in apo(a) levels, but there was a significant age-related decrease in activities of SOD (A>C, B>C: P < 0·01), CAT (A>C: P < 0·05) and GSH-Px (A>C: P < 0·05), accompanied by a significant increase in oxLDL (A<C: P < 0·001; B<C: P < 0·05), ADMA (A<B: P < 0·05; A<C: P < 0·001), MDA (A<C, B<C: P < 0·01) and CD (A<C, B<C: P < 0·01), and a significant decrease in fetuin A (A>C: P < 0·01; B>C: P < 0·05). Consequently, all groups showed significant negative age-associated correlations between CAT and MDA (A, B, C: P < 0·05), GSH-Px and CD (A, C: P < 0·01; B: P < 0·05), SOD and oxLDL (A, B: P < 0·05; C: P < 0·01), and fetuin A and MDA (A: P < 0·01; B, C: P < 0·05), and a significant positive correlation between oxLDL and ADMA (A, B: P < 0·05; C: P < 0·01).

CONCLUSIONS

This study indicates a significant age-related decrease in antioxidant enzyme activities accompanied by significantly increased systemic oxidative stress, which promotes the cardiovascular risk factors oxLDL, ADMA and fetuin A in elderly people.

Serum fetuin-A levels are associated with vascular calcifications and predict cardiovascular events in renal transplant recipients

BACKGROUND AND OBJECTIVES

Vascular calcifications predict cardiovascular disease, the major cause of death in renal transplant recipients (RTRs). We studied the determinants of fetuin-A, a potent circulating calcification inhibitor encoded by the AHSG gene, and tested its association with vascular calcifications and long-term survival and cardiovascular events (CVEs) in RTRs.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Two hundred seventy-seven prevalent RTRs from a single center were included. CVEs and deaths were prospectively recorded during a 5-year follow-up.

RESULTS

Independent determinants of lower serum fetuin-A levels were lower plasma cholesterol, the AHSG rs4918 G allele, and history of smoking. Low serum fetuin-A level was a determinant of aortic calcifications (assessed using spiral CT). Low fetuin-A levels (≤0.47 g/L, first quintile) were independently associated with CVEs and deaths (hazard ratio=1.83; 95% confidence interval, 1.07 to 3.04). The association was confirmed for all-cause mortality, and the major adverse cardiovascular endpoints were analyzed separately. Patients with low fetuin-A and high high-sensitivity C-reactive protein (>4.36 mg/L, fourth quintile) levels had a 3.5-fold increased risk of all-cause mortality and CVEs. In the presence of inflammation, CVE-free survival was influenced by common variants in the AHSG gene.

CONCLUSIONS

These data show that low fetuin-A levels are independently associated with aortic calcifications and a higher risk of CVEs and mortality. They support fetuin-A as a circulating biomarker able to identify RTRs at risk for vascular calcifications and CVEs.