Fetuin-A and risk of coronary heart disease: A Mendelian randomization analysis and a pooled analysis of AHSG genetic variants in 7 prospective studies

Fetuin-A and its genetic association with cardiometabolic disease

Fetuin-A acts as both an inhibitor of calcification and insulin signaling. Previous studies reported conflicting results on the association between fetuin-A and cardiometabolic diseases. We aim to provide further insights into the association between genetically predicted levels of fetuin-A and cardiometabolic diseases using a Mendelian randomization strategy. Genetic variants associated with fetuin-A and their effect sizes were obtained from previous genetic studies. A series of two-sample Mendelian randomization analyses in 412,444 unrelated individuals from the UK Biobank did not show evidence for an association of genetically predicted fetuin-A with any stroke, ischemic stroke, or myocardial infarction. We do find that increased levels of genetically predicted fetuin-A are associated with increased risk of type 2 diabetes (OR = 1.21, 95%CI 1.13-1.30, P =  < 0.01). Furthermore, genetically predicted fetuin-A increases the risk of coronary artery disease in individuals with type 2 diabetes, but we did not find evidence for an association between genetically predicted fetuin-A and coronary artery disease in those without type 2 diabetes (P for interaction = 0.03). One SD increase in genetically predicted fetuin-A decreases risk of myocardial infarction in women, but we do not find evidence for an association between genetically predicted fetuin-A and myocardial infarction in men (P for interaction =  < 0.01). Genetically predicted fetuin-A is associated with type 2 diabetes. Furthermore, type 2 diabetes status modifies the association of genetically predicted fetuin-A with coronary artery disease, indicating that fetuin-A increases risk in individuals with type 2 diabetes. Finally, higher genetically predicted fetuin-A reduces the risk of myocardial infarction in women, but we do not find evidence for an association between genetically predicted fetuin-A and myocardial infarction in men.

Tissue and plasma proteomic profiling indicates AHSG as a potential biomarker for ascending thoracic aortic aneurysms

BACKGROUND

Thoracic Aortic Aneurysms (TAAs) develop asymptomatically and are characterized by dilatation of the aorta. This is considered a life-threatening vascular disorder due to the risk of aortic dissection and rupture. There is an urgent need to identify blood-borne biomarkers for the early detection of TAA. The goal of the present study was to identify potential protein biomarkers associated with TAAs, using proteomic analysis of aortic tissue and plasma samples.

METHODS

Extracted proteins from 14 aneurysmal and 12 non-aneurysmal thoracic aortic tissue specimens as well as plasma samples from six TAA patients collected pre-and postoperatively and six healthy controls (HC), were analyzed by liquid chromatography-tandem mass spectrometry. Proteomic data were further processed and following filtering criteria, one protein was selected for verification and validation in a larger cohort of patients and controls using a targeted quantitative proteomic approach and enzyme-linked immunosorbent assay, respectively.

RESULTS

A total of 1593 and 363 differentially expressed proteins were identified in tissue and plasma samples, respectively. Pathway enrichment analysis on the differentially expressed proteins revealed a number of dysregulated molecular pathways that might be implicated in aneurysm pathology including complement and coagulation cascades, focal adhesion, and extracellular matrix receptor interaction pathways. Alpha-2-HS glycoprotein (AHSG) was selected for further verification in 36 TAA and 21 HC plasma samples using targeted quantitative proteomic approach. The results showed a significantly decreased concentration of AHSG (p = 0.0002) in the preoperative plasma samples compared with HC samples. Further analyses using a larger validation dataset revealed that AHSG protein levels were significantly lower (p = 0.03) compared with HC. Logistic regression analysis on the validation dataset revealed males, advanced age, hypertension and hyperlipidaemia as significant risk factors for TAA.

CONCLUSION

AHSG concentrations distinguish plasma samples derived from TAA patients and controls. The findings of this study suggest that AHSG may be a potential biomarker for TAA that could lead to better diagnostic capabilities.

The role of hepatokines in NAFLD

Non-alcoholic fatty liver disease (NAFLD) is not only a consequence of insulin resistance, but it is also an important cause of insulin resistance and major non-communicable diseases (NCDs). The close relationship of NAFLD with visceral obesity obscures the role of fatty liver from visceral adiposity as the main pathomechanism of insulin resistance and NCDs. To overcome this limitation, in analogy to the concept of adipokines, in 2008 we introduced the term hepatokines to describe the role of fetuin-A in metabolism. Since then, several other hepatokines were tested for their effects on metabolism. Here we address the dysregulation of hepatokines in people with NAFLD. Then, we discuss pathophysiological mechanisms of cardiometabolic diseases specifically related to NAFLD by focusing on hepatokine-related organ crosstalk. Finally, we propose how the determination of major hepatokines and adipokines can be used for pathomechanism-based clustering of insulin resistance in NAFLD and visceral obesity to better implement precision medicine in clinical practice.

Development of a cyclic-inverso AHSG/Fetuin A-based peptide for inhibition of calcification in osteoarthritis

OBJECTIVE

Ectopic calcification is an important contributor to chronic diseases, such as osteoarthritis. Currently, no effective therapies exist to counteract calcification. We developed peptides derived from the calcium binding domain of human Alpha-2-HS-Glycoprotein (AHSG/Fetuin A) to counteract calcification.

METHODS

A library of seven 30 amino acid (AA) long peptides, spanning the 118 AA Cystatin 1 domain of AHSG, were synthesized and evaluated in an in vitro calcium phosphate precipitation assay. The best performing peptide was modified (cyclic, retro-inverso and combinations thereof) and evaluated in cellular calcification models and the rat Medial Collateral Ligament Transection + Medial Meniscal Tear (MCLT + MMT) osteoarthritis model.

RESULTS

A cyclic peptide spanning AA 1-30 of mature AHSG showed clear inhibition of calcium phosphate precipitation in the nM-pM range that far exceeded the biological activity of the linear peptide variant or bovine Fetuin. Biochemical and electron microscopy analyses of calcium phosphate particles revealed a similar, but distinct, mode of action in comparison with bFetuin. A cyclic-inverso variant of the AHSG 1-30 peptide inhibited calcification of human articular chondrocytes, vascular smooth muscle cells and during osteogenic differentiation of bone marrow derived stromal cells. Lastly, we evaluated the effect of intra-articular injection of the cyclic-inverso AHSG 1-30 peptide in a rat osteoarthritis model. A significant improvement was found in histopathological osteoarthritis score and animal mobility. Serum levels of IFNγ were found to be lower in AHSG 1-30 peptide treated animals.

CONCLUSIONS

The cyclic-inverso AHSG 1-30 peptide directly inhibits the calcification process and holds the potential for future application in osteoarthritis.

Genetic Determinants of Serum Calcification Propensity and Cardiovascular Outcomes in the General Population

Background:

Serum calciprotein particle maturation time (T50), a measure of vascular calcification propensity, is associated with cardiovascular morbidity and mortality. We aimed to identify genetic loci associated with serum T50 and study their association with cardiovascular disease and mortality.

Methods:

We performed a genome-wide association study of serum T50 in 2,739 individuals of European descent participating in the Prevention of REnal and Vascular ENd-stage Disease (PREVEND) study, followed by a two-sample Mendelian randomization (MR) study to examine causal effects of T50 on cardiovascular outcomes. Finally, we examined associations between T50 loci and cardiovascular outcomes in 8,566 community-dwelling participants in the Rotterdam study.

Results:

We identified three independent genome-wide significant single nucleotide polymorphism (SNPs) in the AHSG gene encoding fetuin-A: rs4917 (p = 1.72 × 10−101), rs2077119 (p = 3.34 × 10−18), and rs9870756 (p = 3.10 × 10−8), together explaining 18.3% of variation in serum T50. MR did not demonstrate a causal effect of T50 on cardiovascular outcomes in the general population. Patient-level analyses revealed that the minor allele of rs9870756, which explained 9.1% of variation in T50, was associated with a primary composite endpoint of all-cause mortality or cardiovascular disease [odds ratio (95% CI) 1.14 (1.01–1.28)] and all-cause mortality alone [1.14 (1.00–1.31)]. The other variants were not associated with clinical outcomes. In patients with type 2 diabetes or chronic kidney disease, the association between rs9870756 and the primary composite endpoint was stronger [OR 1.40 (1.06–1.84), relative excess risk due to interaction 0.54 (0.01–1.08)].

Conclusions:

We identified three SNPs in the AHSG gene that explained 18.3% of variability in serum T50 levels. Only one SNP was associated with cardiovascular outcomes, particularly in individuals with type 2 diabetes or chronic kidney disease.

Fetuin-A and risk of diabetes-related vascular complications: a prospective study

BACKGROUND

Fetuin-A is a hepatokine which has the capacity to prevent vascular calcification. Moreover, it is linked to the induction of metabolic dysfunction, insulin resistance and associated with increased risk of diabetes. It has not been clarified whether fetuin-A associates with risk of vascular, specifically microvascular, complications in patients with diabetes. We aimed to investigate whether pre-diagnostic plasma fetuin-A is associated with risk of complications once diabetes develops.

METHODS

Participants with incident type 2 diabetes and free of micro- and macrovascular disease from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort (n = 587) were followed for microvascular and macrovascular complications (n = 203 and n = 60, respectively, median follow-up: 13 years). Plasma fetuin-A was measured approximately 4 years prior to diabetes diagnosis. Prospective associations between baseline fetuin-A and risk of complications were assessed with Cox regression.

RESULTS

In multivariable models, fetuin-A was linearly inversely associated with incident total and microvascular complications, hazard ratio (HR, 95% CI) per standard deviation (SD) increase: 0.86 (0.74; 0.99) for total, 0.84 (0.71; 0.98) for microvascular and 0.92 (0.68; 1.24) for macrovascular complications. After additional adjustment for cardiometabolic plasma biomarkers, including triglycerides and high-density lipoprotein, the associations were slightly attenuated: 0.88 (0.75; 1.02) for total, 0.85 (0.72; 1.01) for microvascular and 0.95 (0.67; 1.34) for macrovascular complications. No interaction by sex could be observed (p > 0.10 for all endpoints).

CONCLUSIONS

Our data show that lower plasma fetuin-A levels measured prior to the diagnosis of diabetes may be etiologically implicated in the development of diabetes-associated microvascular disease.

Fetuin-A to adiponectin ratio is an independent indicator of subclinical atherosclerosis in patients with newly diagnosed type 2 diabetes mellitus

AIMS

The purpose of this research was to explore the associations of fetuin-A, adiponectin, and fetuin-A/adiponectin ratio (F/A ratio) with subclinical atherosclerosis as evaluated by carotid intima-media thickness (CIMT) in cases with newly diagnosed type 2 diabetes mellitus (T2DM).

METHODS

A total of 283 newly diagnosed T2DM patients were enrolled in this study. Serum fetuin-A and adiponectin levels were determined with an ELISA method. Other clinical and biochemical parameters were also collected.

RESULTS

Significant linear increases in waist-to-hip ratio (WHR), systolic blood pressure (SBP), diastolic blood pressure, homoeostasis model assessment of insulin resistance, C-reactive protein (CRP) and F/A ratio, and a significant linear decrease in adiponectin with increasing tertiles of CIMT were observed (P for trends <0.05). However, no significant correlation between fetuin-A and CIMT was detected (P > 0.05). In multivariate logistic regression models, WHR, SBP and F/A ratio were independently correlated with higher CIMT. Receiver operating characteristic curve analysis indicated that F/A ratio had a better predictive power for higher CIMT than adiponectin and fetuin-A, with an area under the curve of 0.802, 0.713 and 0.646, respectively.

CONCLUSION

F/A ratio is an independent indicator of subclinical atherosclerosis in patients with newly diagnosed T2DM.

The relationship between fetuin-A and coronary atherosclerotic heart disease (CHD) and CHD-related risk factors: A retrospective study

Fetuin-A plays an important role in antivascular calcification and inflammatory response, it is necessary to explore the relationship between fetuin-A and coronary atherosclerotic heart disease (CHD) and CHD-related risk factors.A total of 92 patients with CHD as the research group, and 60 healthy persons as the control group were enrolled from May 2019 to May 2020. Fetuin-A levels were determined by enzyme-linked immunosorbent assay, and the characteristics and clinical data were collected and compared. Logistic regression was used to analyze the factors influencing CHD.The age, proportion of males, patients with hypertension and diabetes, as well as fetuin-A level in the research group were significantly higher than those in the control group, but the high-density lipoprotein cholesterol level was significantly lower than that in the control group (P < .05). Logistic regression analysis and correction showed that gender, age, blood pressure, and diabetes were related to the onset of CHD, and there was a significant correlation between the level of fetuin-A and age (P < .05).Serum fetuin-A was related to the onset risk of CHD, and showed a significant correlation with age.

Non-alcoholic fatty liver disease and cardiovascular disease: assessing the evidence for causality

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent among individuals with type 2 diabetes. Although epidemiological studies have shown that NAFLD is associated with cardiovascular disease (CVD), it remains unknown whether NAFLD is an active contributor or an innocent bystander. Plasma lipids, low-grade inflammation, impaired fibrinolysis and hepatokines are potential mediators of the relationship between NAFLD and CVD. The Mendelian randomisation approach can help to make causal inferences. Studies that used common variants in PNPLA3, TM6SF2 and GCKR as instruments to investigate the relationship between NAFLD and coronary artery disease (CAD) have reported contrasting results. Variants in PNPLA3 and TM6SF2 were found to protect against CAD, whereas variants in GCKR were positively associated with CAD. Since all three genes have been associated with non-alcoholic steatohepatitis, the second stage of NAFLD, the question of whether low-grade inflammation is an important mediator of the relationship between NAFLD and CAD arises. In contrast, the differential effects of these genes on plasma lipids (i.e. lipid-lowering for PNPLA3 and TM6SF2, and lipid-raising for GCKR) strongly suggest that plasma lipids account for their differential effects on CAD risk. This concept has recently been confirmed in an extended set of 12 NAFLD susceptibility genes. From these studies it appears that plasma lipids are an important mediator between NAFLD and CVD risk. These findings have important clinical implications, particularly for the design of anti-NAFLD drugs that also affect lipid metabolism.

Association of AHSG gene polymorphisms with serum Fetuin-A levels in individuals with cardiovascular calcification in west of Iran

Fetuin-A (AHSG) is a multifunctional secretory protein and acts as an ectopic valve and artery calcification inhibitor. We assessed the correlation between serum levels of Fetuin-A and both exon 6 (248 C/T) and exon 7 (256 C/G) mutations in patients with coronary artery calcification (CAC), mitral annular calcification (MAC), and aortic valve calcification (AVC). 184 patients and 184 healthy individuals as control group were included. The genetic variants of rs4917 and rs4918 for the AHSG gene were determined by PCR-RFLP and T-ARMS PCR techniques. Fetuin-A levels, fasting blood sugar (FBS), urea, creatinine, calcium phosphorus, and lipid profile were measured. Fetuin-A levels were remarkedly lower in individuals with AVC, MAC, and CAC comparing to the control group (p < 0.001). The CT + TT genotypes and the T allele (AHSG Thr248Met) were associated with the risk of calcification of heart valves and coronary artery by 1.31 and 1.27 times in the patient group, respectively. The frequency of CT genotype and T allele was considerably higher in the patient group comparing to the control group. Patients with T allele (CT + TT) had higher levels of FBS, urea, low-density lipoproteins (LDL)-C, phosphorus, systolic blood pressure (SBP), diastolic blood pressure (DBP) while decreased levels of triglyceride, high-density lipoproteins (HDL)-C, calcium and fetuin-A in comparison to control group. Additionally, there was a positive correlation between serum FBS, urea, creatinine, HDL-C, calcium with fetuin-A, and a negative correlation between phosphorous level, SBP, and DBP with fetuin-A. T allele in rs4917 Single nucleotide polymorphism (SNP) is the risk allele of calcification of heart valves and coronary arteries and fetuin-A levels correlates negatively with the occurrence of the disease.

Fetuin-A – Alpha2-Heremans-Schmid Glycoprotein: From Structure to a Novel Marker of Chronic Diseases Part 2. Fetuin-A – A Marker of Insulin Resistance and Related Chronic Diseases

Fetuin-A is a secretory liver glycoprotein with multiple physiological functions such as regulation of insulin resistance, tissue calcification, bone metabolism, cellular proteolytic activity, and self-proliferative signaling.

Fetuin-A is a unique molecule which binds to the insulin receptor, modulating its sensitivity, and transducing “the physiological conditions” (serum levels of the metabolites like glucose, free fatty acids, inflammatory signals) from outside into inside the cells. Plasma fetuin-A levels correlate with reduced glucose tolerance and insulin resistance. Impaired insulin sensitivity leads to the development of metabolic syndrome, an increased risk for type 2 diabetes (T2DM), dyslipidaemias and cardiovascular diseases (CVDs). Furthermore, fetuin-A inversely correlates with inflammatory and activation biomarkers, e.g. in patients with T2DM. Thus, circulatory fetuin-A levels may have plausible predictive importance as a biomarker of risk of diabetes and negative acute phase protein. Dysregulated, it plays a crucial role in the pathogenesis of some metabolic disorders and clinical inflammatory conditions like metabolic syndrome, T2DM, CVDs, polycystic ovary syndrome (PCOS), etc.

From genome-wide association studies to Mendelian randomization: novel opportunities for understanding cardiovascular disease causality, pathogenesis, prevention, and treatment

The Mendelian randomization approach is an epidemiological study design incorporating genetic information into traditional epidemiological studies to infer causality of biomarkers, risk factors, or lifestyle factors on disease risk. Mendelian randomization studies often draw on novel information generated in genome-wide association studies on causal associations between genetic variants and a risk factor or lifestyle factor. Such information can then be used in a largely unconfounded study design free of reverse causation to understand if and how risk factors and lifestyle factors cause cardiovascular disease. If causation is demonstrated, an opportunity for prevention of disease is identified; importantly however, before prevention or treatment can be implemented, randomized intervention trials altering risk factor levels or improving deleterious lifestyle factors needs to document reductions in cardiovascular disease in a safe and side-effect sparse manner. Documentation of causality can also inform on potential drug targets, more likely to be successful than prior approaches often relying on animal or cell studies mainly. The present review summarizes the history and background of Mendelian randomization, the study design, assumptions for using the design, and the most common caveats, followed by a discussion on advantages and disadvantages of different types of Mendelian randomization studies using one or more samples and different levels of information on study participants. The review also provides an overview of results on many of the risk factors and lifestyle factors for cardiovascular disease examined to date using the Mendelian randomization study design.

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 impact of the AHSG genetic polymorphism on the risk of ischemic stroke: a case-control study

Ischemic stroke (IS) is a complex disease caused by an obstruction within a brain-supplying blood vessel that involves both genetic and environmental factors. In this study, we evaluated the association of genetic polymorphisms in the AHSG gene with ischemic stroke risk in the Chinese population. A case-control study was conducted that included 477 nephropathy patients and 490 healthy controls. Chi-squared tests and a genetic model were used to evaluate associations. In the genetic model analysis, we identified that the SNP of rs2070634 in the AHSG gene was associated with a 1.37-fold increase the risk of stroke in the co-dominant model (adjusted, the "G/T" genotype), and a 1.40-fold increase the risk of stroke in the Over-dominant model (adjusted, the "G/T" genotype), respectively. The rs2518136 in the AHSG gene was associated with a 1.37-fold increase the risk of stroke in the co-dominant model (adjusted, the "T/C" genotype) and a 1.41-fold decrease the risk of stroke in the over-dominant model (adjusted, the "T/C" genotype), respectively. We found four SNPs (rs2248690, rs2070634, rs4917 and rs2518136) show a strong linkage, but the AHSG haplotype was not found to be associated with a risk of ischemic stroke. The present study suggests that the AHSG polymorphism may contribute to an increased risk of ischemic stroke.

Clinical effects of electrical stimulation therapy on lumbar disc herniation-induced sciatica and its influence on peripheral ROS level

OBJECTIVE

To study the clinical effects of electrical stimulation therapy on lumbar disc herniation-induced sciatica and its influence on peripheral reactive oxygen species (ROS) level.

METHODS

100 patients with lumbar disc herniation-induced sciatica were selected, and were randomly divided into the control and research group. The control group was treated with traction and other basic therapies, while the research group was treated with electrical stimulation. The pain degrees, peripheral ROS levels and clinical effects prior to treatment and at 4 weeks after treatment were examined.

RESULTS

The total cure-remarkable-effectiveness rate of patients in research group was higher than that in control group (p<0.05). Before treatment, the pain rating index (PRI), present pain intensity (PPI) and visual analogue scale (VAS) score had no statistically significant differences between the two groups. After treatment, PRI, PPI and VAS scores in the two groups were lower than those prior to treatment; these indexes in research group were lower than those in control group, and the differences were statistically significant (p<0.05). After treatment, the peripheral ROS levels in the two groups were lower than those before treatment; it was lower in research group than that in control group (p<0.05).

CONCLUSION

Electrical stimulation has a significant effect in the treatment of lumbar disc herniation-induced sciatica, which can effectively reduce the pain, alleviate the clinical symptoms and signs of patients, regulate the peripheral ROS level, and prevent the oxidative damage of myocardial tissues.

Gene delivery system of pDNA using the blood glycoprotein fetuin

Fetuin is a biocompatible plasma protein and strongly enhances phagocytosis of bacteria, DNA and apoptotic cells by peripheral blood cells such as monocytes, macrophages and dendritic cells. We developed a novel gene delivery system: ternary complexes constructed with pDNA, polyethylenimine (PEI) and fetuin. Without covalent binding, fetuin was able to coat pDNA-PEI complexes, and stable anionic nanoparticles formed at a weight ratio greater than 30. Optimised pDNA-PEI-fetuin complexes significantly decreased the cytotoxicity of pDNA-PEI complexes in the melanoma cell line B16F10. Furthermore, the pDNA-PEI-fetuin complexes had higher transgene efficiency compared to that of commercial lipofectin previously reported in B16F10 cells despite an anionic surface. The pDNA-PEI-fetuin complexes did not agglutinate with erythrocytes. The pDNA-PEI-fetuin complexes had high gene expression in the spleen after intravenous administration in mice. Thus, the pDNA-PEI-fetuin complexes were a useful in vivo gene delivery system with tropism for the spleen.

Detection of genetic loci associated with plasma fetuin-A: a meta-analysis of genome-wide association studies from the CHARGE Consortium

Plasma fetuin-A is associated with type 2 diabetes, and AHSG, the gene encoding fetuin-A, has been identified as a susceptibility locus for diabetes and metabolic syndrome. Thus far, unbiased investigations of the genetic determinants of plasma fetuin-A concentrations have not been conducted. We searched for single nucleotide polymorphisms (SNPs) related to fetuin-A concentrations by a genome-wide association study in six population-based studies. We examined the association of fetuin-A levels with ∼ 2.5 million genotyped and imputed SNPs in 9,055 participants of European descent and 2,119 African Americans. In both ethnicities, the strongest associations were centered in a region with a high degree of LD near the AHSG locus. Among 136 genome-wide significant (P < 0.05 × 10-8) SNPs near the AHSG locus, the top SNP was rs4917 (P =1.27 × 10-303), a known coding SNP in exon 6 that is associated with a 0.06 g/l (∼13%) lower fetuin-A level. This variant alone explained 14% of the variation in fetuin-A levels. Analyses conditioned on rs4917 indicated that the strong association with the AHSG locus stems from additional independent associations of multiple variants among European Americans. In conclusion, levels of fetuin-A in plasma are strongly associated with SNPs in its encoding gene, AHSG, but not elsewhere in the genome. Given the strength of the associations observed for multiple independent SNPs, the AHSG gene is an example of a candidate locus suitable for additional investigations including fine mapping to elucidate the biological basis of the findings and further functional experiments to clarify AHSG as a potential therapeutic target.

Fetuin-A, glycemic status, and risk of cardiovascular disease: The Multi-Ethnic Study of Atherosclerosis

AIMS

Fetuin-A is a hepatic secretory protein that both promotes insulin resistance and inhibits arterial calcification. Previous studies have suggested that the association of fetuin-A with incident cardiovascular disease (CVD) might be modified by glycemic status.

METHODS AND RESULTS

We conducted a case-cohort study of fetuin-A and incident non-fatal CVD nested in the Multi-Ethnic Study of Atherosclerosis with follow-up from 2000 to 2007. Fetuin-A concentrations were measured from baseline serum samples among 2505 randomly selected subcohort members and 142 incident cases. In weighted multivariable Cox regression models, no association was observed between fetuin-A and incident CVD in the total study population (HR per SD = 1.01; 95% CI: 0.84, 1.23). Although associations with CVD events were not statistically significant within categories of glycemic status, our results tended to support the interaction with glycemic status observed in other studies, with a positive trend restricted to participants with impaired fasting glucose or diabetes (HR per SD = 1.20; 95% CI: 0.89, 1.63) and an inverse trend among normoglycemic individuals (HR = 0.89; 95% CI: 0.69-1.13) (p-interaction = 0.04). In addition, we observed significant interaction between fasting glucose and fetuin-A when both were treated continuously in the subset of participants not using diabetes medication (p-interaction = 0.006).

CONCLUSION

Our results suggest that fetuin-A is not associated with an overall risk of CVD, but support prior evidence indicating that the association might be modified by glycemic status.