Rationale & Objective: Afamin is a vitamin Ebinding glycoprotein primarily expressed in the liver and kidney. This study investigated whether serum afamin concentrations are associated with kidney function and incident kidney failure. Study Design: Prospective cohort study with 6.5 years follow-up. Setting & Participants: 5,041 White patients enrolled in the German Chronic Kidney Disease (GCKD) study with measured afamin concentrations and either an estimated glomerular filtration rate (eGFR) of 30-60 mL/min/1.73 m2 or an eGFR > 60 mL/min/1.73 m2 with a urinary albumin-creatinine ratio (UACR) of >= 300 mg/g at study entry. Exposure: Serum afamin concentrations (mg/L). Outcome: Incident kidney failure (initiation of kidney replacement therapy or kidney-related death). Analytical Approach: Generalized linear regression and quantile regression models fit to investigate the association of afamin concentrations with eGFR and UACR. Adjusted Cox regression analysis to examine the association of afamin concentrations with incident kidney failure. Results: The mean +/- SD afamin concentration at study entry was 73.2 +/- 17.6 mg/L. Higher afamin concentrations were associated with better kidney function with a 2.60 mL/min/1.73 m2 higher eGFR (95% CI, 2.30-2.8 9) and a 5.97 mg/g lower UACR (95% CI, 3.04-8.9 0) for each 10 mg/L higher level of afamin concentration in adjusted analysis. During the follow-up period, each 10 mg/L higher level of afamin concentration was associated with a 14% lower risk of kidney failure (HR, 0.86 [95%CI, 0.810.92], P < 0.001). Limitations: Residual confounding, and potential limited generalizability to non-White populations and people with mild stages of chronic kidney disease (CKD) or no CKD. Conclusions: Higher serum afamin concentrations appear to be associated with a higher eGFR, less albuminuria, and a lower risk for future kidney failure in patients with CKD.

BACKGROUND:Previous studies suggest that afamin is associated with steatotic liver diseases (SLD). However, the exact role of afamin in SLD development and fibrogenesis remains unclear. Potential modifying effects of sex and glucose tolerance status have also not been examined. Therefore, we investigated the associations of afamin with steatotic liver diseases and fibrosis defined by non-invasive tests and assessed for possible effect modifications. METHODS:This study included 3080 participants from the population-based KORA F4/FF4 cohort. Cross-sectional and prospective associations (follow-up time 6.5 years) between afamin and NAFLD liver fat score (NAFLD LFS), hepatic steatosis index, fatty liver index and the fibrosis-4 index were assessed using multiple linear regression models. Models were adjusted for age, sex, body mass index, smoking status, alcohol consumption, physical activity, metabolic parameters, medication and subclinical inflammation. RESULTS:In the cross-sectional analysis, afamin concentrations were positively associated with NAFLD LFS (β = .32; 95% CI .27-.37), hepatic steatosis index (β = .33; 95% CI .26-.39) and fatty liver index (β = 1.78; 95% CI 1.47-2.08) (all p < .001), but not with fibrosis-4 index. In the prospective analysis, higher afamin levels were associated with a higher increase only in NAFLD LFS (p < .001). Cross-sectional and prospective associations between afamin and NAFLD LFS were more pronounced in men than in women (pinteraction < .001 and .022; respectively). Cross-sectional associations between afamin and NAFLD LFS were also stronger in individuals with prediabetes or diabetes compared to those with normal glucose tolerance (pinteraction < .001). CONCLUSION:Higher afamin concentrations are positively associated with NAFLD LFS with potential effect modification by sex and glucose tolerance status.

Lipoprotein(a) [Lp(a)] is a genetically determined causal risk factor for atherosclerotic diseases. In patients with various kidney diseases, Lp(a) plasma concentrations are, however, non-genetically elevated, secondary to the kidney insufficiency, suggesting a catabolic role of the kidney in Lp(a) metabolism. This review summarizes the complex interrelationship between Lp(a) concentrations and kidney function based upon epidemiological and genetic studies as well as results from in vitro experiments and work from animal models and in vivo kinetic studies in humans. Both biosynthesis and assembly as well as catabolism of Lp(a) are despite numerous investigations in various experimental model system, poorly understood. In contrast to low-density lipoproteins, no clear receptor-mediated clearance mechanism could be identified for Lp(a). Epidemiological studies with various patient groups of chronic kidney disease (CKD) revealed increased Lp(a) concentrations in CKD patients that normalize to values of healthy controls after kidney transplantation. In hemodialyzed patients, elevated Lp(a) concentrations could only be observed in those patients with high molecular weight apo(a) isoforms. In vivo kinetic studies in hemodialyzed patients resulted in reduced catabolic rates, compared to controls. Immunohistochemical experiments on healthy kidney tissue showed positive immunostaining for Lp(a). Together with the finding of arterio-venous renal gradients of Lp(a) concentrations and the discovery of substantial amounts of apo(a) fragments in the urine, these results strongly suggest a substantial role of the kidney in Lp(a) catabolism. As in the general population, cardiovascular disease is also a major cause of death in CKD patients. In line with the apo(a)-isoform-specific elevations of Lp(a) in CKD patients, the majority of studies revealed Lp(a) concentrations, in addition to the low molecular weight apo(a) isoforms, as independent risk factors for cardiovascular disease in CKD.

Routine genetic testing in hypercholesterolemia patients reveals a causative monogenic variant in less than 50% of affected individuals. Incomplete genetic characterization is partly due to polygenic factors influencing low-density-lipoprotein-cholesterol (LDL-C). Additionally, functional variants in the LPA gene affect lipoprotein(a)-associated cholesterol concentrations but are difficult to determine due to the complex structure of the LPA gene. In this study we examined whether complementing standard sequencing with the analysis of genetic scores associated with LDL-C and Lp(a) concentrations improves the diagnostic output in hypercholesterolemia patients. 1.020 individuals including 252 clinically diagnosed hypercholesterolemia patients from the FH Register Austria were analyzed by massive-parallel-sequencing of candidate genes combined with array genotyping, identifying nine novel variants in LDLR. For each individual, validated genetic scores associated with elevated LDL-C and Lp(a) were calculated based on imputed genotypes. Integrating these scores especially the score for Lp(a) increased the proportion of individuals with a clearly defined disease etiology to 68.8% compared to 46.6% in standard genetic testing. The study highlights the major role of Lp(a) in disease etiology in clinically diagnosed hypercholesterolemia patients, of which parts are misclassified. Screening for monogenic causes of hypercholesterolemia and genetic scores for LDL-C and Lp(a) permits more precise diagnosis, allowing individualized treatment.

Background and Aims: To identify, characterize and evaluate individuals with familial hypercholesterolemia (FH). Methods: Patients were enrolled at 14 clinical centres across Austria following signed informed consent based on Dutch Lipid Clinic Network scores (≥6), modified Simon-Broome criteria, or results from cascade screening. The study was approved by local research ethics committees. Results: A total of 1158 individuals enrolled since inception in 2015, with 21% of participants <18 years. In total, 20% were identified through cascade screening. Genetic and clinical diagnosis of FH was available for 44%, while 25% were included based solely on clinical diagnosis, and 13% had a genetic diagnosis without the clinical features of FH. For 18% complete data were still missing. Two percent had homozygous FH. Among adult and paediatric participants, the mean age (± SD) at diagnosis was 45 ± 17 and 7 ± 4 years, respectively. Sixteen percent had already experienced a myocardial infarction. At baseline, 77% of adults and 30% of the paediatric population were on lipid-lowering medication (LLM). Overall, 40% were on combination therapy, with statins and ezetimibe being the most prevalent combination (40%), followed by statins, ezetimibe plus PCSK9 inhibitors (23%). At inclusion, 11% of adults attained LDL-Cholesterol levels <70 mg/dl, while 34% of 10- to 17-year-old participants reached their goal (<130 mg/dl). Follow-up visits were available for 138 participants, in which 15% of adults attained target LDL-Cholesterol. Conclusions: Compared to recent global data, a higher proportion of Austrian FH patients takes combination LLM, and more individuals achieve LDL-Cholesterol targets. However, FH remains underdiagnosed and undertreated.

Abstract Objectives In the general population, increased afamin concentrations are associated with the prevalence and incidence of metabolic syndrome as well as type 2 diabetes. Although metabolic syndrome is commonly associated with nonalcoholic fatty liver disease (NAFLD), there exist no information on afamin and NAFLD. Methods Afamin concentrations were cross-sectionally measured in 146 Austrian patients with NAFLD, in 45 patients without NAFLD, and in 292 age- and sex-matched healthy controls. Furthermore, the feasibility of afamin to predict incident NAFLD was evaluated in 1,434 adult participants in the population-based Cardiovascular Risk in Young Finns Study during a 10-year follow-up. Results Median afamin concentrations were significantly higher in NAFLD patients (83.6 mg/L) than in patients without NAFLD (61.6 mg/L, p<0.0001) or in healthy controls (63.9 mg/L, p<0.0001). In age- and sex-adjusted logistic regression analyses a 10 mg/L increase of afamin was associated with a 1.5-fold increase of having NAFLD as compared with patients without NAFLD and the risk was even two-fold when compared with healthy controls. In the population-based cohort, afamin concentrations at baseline were significantly lower in participants without NAFLD (n=1,195) than in 239 participants who developed NAFLD (56.5 vs. 66.9 mg/L, p<0.0001) during the 10-year follow up, with highest afamin values observed in individuals developing severe forms of NAFLD. After adjustment for several potentially confounding parameters, afamin remained an independent predictor for the development of NAFLD (OR=1.37 [95% CI 1.23–1.54] per 10 mg/L increase, p<0.0001). Conclusions Afamin concentrations are increased in patients with NAFLD and independently predict the development of NAFLD in a population-based cohort.

An angeborene Störungen des Fettstoffwechsels ist zu denken, wenn bei jungen Individuen die Konzentrationen des LDL-C über 190 mg/dl (4,9 mmol/l) und/oder der Triglyzeride über 200 mg/dl (2,3 mmol/l) liegen, eine sekundäre Hyperlipoproteinämie (HLP) ausgeschlossen ist oder sich bei Angehörigen ebenfalls erhöhte Lipidkonzentrationen oder frühzeitige Herzinfarkte finden. Für eine primäre HLP spricht auch das Auftreten von Xanthelasmen, Arcus lipoides, Xanthomen und abdominellen Beschwerden. Diese Übersicht fasst den Stand der Kenntnisse zur Ätiologie und Pathogenese dieser primären HLP zusammen.

Congenital disorders of lipid metabolism are characterised by LDL-C concentrations > 190 mg/dl (4.9 mM) and/or triglycerides > 200 mg/dl (2.3 mM) in young individuals after having excluded a secondary hyperlipoproteinemia. Further characteristics of this primary hyperlipoproteinemia are elevated lipid values or premature myocardial infarctions within families or xantelasms, arcus lipoides, xanthomas and abdominal pain. This overview summarises our current knowledge of etiology and pathogenesis of primary hyperlipoproteinemia.

Background and aims: FH is still underdiagnosed. Cost-effectiveness results of preventive screening strategies vary. We aimed at systematically assessing the benefits, harms and cost effectiveness of screening for familial hypercholesterolemia (FH) and at providing an overview of the main characteristics and methodological ap-proaches of applied decision-analytic models. Methods: A systematic literature search was conducted in MEDLINE, EconLit, CRD-databases and the CEA-registry for FH screening starting 2012. Earlier studies were included from a published systematic review. Results were reported in standardized semi-quantitative evidence tables. Costs were converted to current euros. Incremental cost-effectiveness ratios (ICERs) were recalculated according to economic guidelines.Results: Out of our 211 retrieved studies, eight were included in the review in addition to six studies from an earlier review. Studies were conducted in Europe (UK, The Netherlands, Spain, Poland), USA and Australia evaluating cascade (CS), opportunistic (OS), universal screening (UniS), or combinations using genetic testing, clinical criteria or combinations. Studies evaluating only CS identified strategies with an ICER of up to 37,100 EUR/quality-adjusted life-year (QALY) but some strategies were dominated depending on test combinations. UniS of newborns in combination with CS had an ICER & LE;15,000 EUR/QALY for sequential cholesterol-genetic screening. In other studies, UniS was dominated by OS/CS. Conclusions: Our systematic review demonstrates the values of FH screening and provides an overview of potentially relevant screening strategies to be tested using a decision-analytic model for the respective country or region. Future research is needed on the transferability of results to other countries and modeling spillover effects to newborns.

Background and aims: Familial hypercholesterolaemia (FH) is commonly caused by mutations in the LDLR, APOB or PCSK9 genes, with untreated mean low density lipoprotein-cholesterol (LDL-C) concentrations being elevated in APOB mutation carriers, even higher in LDLR mutation and highest in those with a PCSK9 mutation. Here we examine this in children with FH from Norway, UK, The Netherlands, Belgium, Czech Republic, Austria, Portugal and Greece. Methods: Differences in characteristics and preand post-treatment lipid concentrations in those with different molecular causes were compared by standard statistical tests. Results: Data were obtained from 2866 children, of whom 2531 (88%) carried a reported LDLR/APOB/PCSK9 variant. In all countries, the most common cause of FH was an LDLR mutation (79% of children, 297 different), but the prevalence of the APOB p.(Arg3527Gln) mutation varied significantly (ranging from 0% in Greece to 39% in Czech Republic, p < 2.2 x 10(-16)). The prevalence of a family history of premature CHD was significantly higher in children with an LDLR vs APOB mutation (16% vs 7% p=0.0005). Compared to the LDLR mutation group, mean (+/- SD) concentrations of pre-treatment LDL-C were significantly lower in those with an APOB mutation (n = 2260 vs n = 264, 4.96 (1.08)mmol/l vs 5.88 (1.41)mmol/l, p < 2.2 x 10(-16)) and lowest in those with a PCSK9 mutation (n = 7, 4.71 (1.22)mmol/l). Conclusions: The most common cause of FH in children from eight European countries was an LDLR mutation, with the prevalence of the APOB p.(Arg3527Gln) mutation varying significantly across countries. In children, LDLR-FH is associated with higher concentrations of LDL-C and family history of CHD compared to those with APOB-FH.

AimAfamin is a liver-produced glycoprotein, a potential early marker of metabolic syndrome. Here we investigated regulation of afamin in a course of the metabolic disease development and in response to 3-month exercise intervention.MethodsWe measured whole-body insulin sensitivity (euglycemic hyperinsulinemic clamp), glucose tolerance, abdominal adiposity, hepatic lipid content (magnetic resonance imaging/spectroscopy), habitual physical activity (accelerometers) and serum afamin (enzyme-linked immunosorbent assay) in 71 middle-aged men with obesity, prediabetes and newly diagnosed type 2 diabetes. Effects of 3-month exercise were investigated in 22 overweight-to-obese middle-aged individuals (16M/6F).ResultsPrediabetes and type 2 diabetes, but not obesity, were associated with increased serum afamin (p<0.001). Afamin correlated positively with hepatic lipids, fatty liver index and liver damage markers; with parameters of adiposity (waist circumference, %body fat, adipocyte diameter) and insulin resistance (fasting insulin, C-peptide, HOMA-IR; p<0.001 all). Moreover, afamin negatively correlated with whole-body insulin sensitivity (M-value/Insulin, p<0.001). Hepatic lipids and fasting insulinemia were the most important predictors of serum afamin, explaining >63% of its variability. Exercise-related changes in afamin were paralleled by reciprocal changes in insulinemia, insulin resistance and visceral adiposity. No significant change in hepatic lipid content was observed.ConclusionsSubjects with prediabetes and type 2 diabetes had the highest serum afamin levels. Afamin was more tightly related to hepatic lipid accumulation, liver damage and insulin resistance than to obesity.

BACKGROUND AND AIMS:Lipoprotein (a) [Lp(a)] is an established causal risk factor for cardiovascular disease (CVD), independently of low-density lipoproteins (LDL) and other risk factors. The recognition of Lp(a) as an atherogenic molecule has raised the demand for reliable quantification methods in the clinical laboratory. The aim of this work is to compare commercial immunochemical assays. METHODS:We measured Lp(a) serum concentrations using six different assays, providing Lp(a) in mg/dl (Denka Seiken, Abbott Quantia, Beckman, Diasys 21FS, and Siemens N Latex) or in nmol/l (Roche TinaQuant, Diasys 21 FS) in 144 serum samples covering the clinically relevant range of Lp(a) concentrations. All assays relied on five-point calibrations using calibrators provided by the manufacturers. Apolipoprotein(a) phenotyping was performed by sodium dodecyl sulfate-agarose gel electrophoresis (SDS-agarose) followed by immunoblotting. RESULTS:Most bivariate correlation coefficients were greater than 0.90. Compared to an established IFCC-proposed reference material, the results of the different assays diverged from the target values (43.3 mg/dl or 96.6 nmol/l) by -8% (Siemens N Latex) and +22% (Abbott Quantia). Stratification of the samples into five groups with increasing Lp(a) concentrations and difference plots showed that the differences among assays were concentration-dependent. Some assays overestimated Lp(a) at high concentrations compared to the Denka Seiken assay. CONCLUSIONS:Current commercial immunological assays for measuring Lp(a) concentrations are differently calibrated. Their biases differ significantly across the clinically relevant concentration range in a non-linear manner. This is not conclusively explained by apolipoprotein (a) phenotypes. Further international efforts to harmonize assays for Lp(a) are needed.

Background: Patients suffering from polycystic ovary syndrome (PCOS) are often insulin resistant and at elevated risk for developing gestational diabetes mellitus (GDM). The aim of this study was to explore afamin, which can be determined preconceptionally to indicate patients who will subsequently develop GDM. Serum concentrations of afamin are altered in conditions of oxidative stress like insulin resistance (IR) and correlate with the gold standard of IR determination, the HOMA index. Methods: Afamin serum concentrations and the HOMA index were analyzed post hoc in 63 PCOS patients with live births. Patients were treated at Essen University Hospital, Germany, between 2009 and 2018. Mann-Whitney U test, T test, Spearman's correlation, linear regression models and receiver-operating characteristic (ROC) analyses were performed for statistical analysis. Results: Patients who developed GDM showed significantly higher HOMA and serum afamin values before their pregnancy (P < 0.001, respectively). ROCS for afamin concentrations showed an area under the curve of 0.78 (95% confidence interval (CI) 0.65-0.90) and of 0.77 (95% CI 0.64-0.89) for the HOMA index. An afamin threshold of 88.6 mg/L distinguished between women who will develop GDM and those who will not with a sensitivity of 79.3% and a specificity of 79.4%. A HOMA index of 2.5 showed a sensitivity of 65.5% and a specificity of 88.2%. Conclusion: The HOMA index and its surrogate parameter afamin are able to identify pre-pregnant PCOS patients who are at risk to develop GDM. Serum afamin concentrations are independent of fasting status and therefore an easily determinable biomarker.

Afamin is an 87 kDa glycoprotein with five predicted N-glycosylation sites. Afamin's glycan abundance contributes to conformational and chemical inhomogeneity presenting great challenges for molecular structure determination. For the purpose of studying the structure of afamin, various forms of recombinantly expressed human afamin (rhAFM) with different glycosylation patterns were thus created. Wild-type rhAFM and various hypoglycosylated forms were expressed in CHO, CHO-Lec1, and HEK293T cells. Fully nonglycosylated rhAFM was obtained by transfection of point-mutated cDNA to delete all N-glycosylation sites of afamin. Wild-type and hypo/nonglycosylated rhAFM were purified from cell culture supernatants by immobilized metal ion affinity and size exclusion chromatography. Glycan analysis of purified proteins demonstrated differences in micro- and macro-heterogeneity of glycosylation enabling the comparison between hypoglycosylated, wild-type rhAFM, and native plasma afamin. Because antibody fragments can work as artificial chaperones by stabilizing the structure of proteins and consequently enhance the chance for successful crystallization, we incubated a Fab fragment of the monoclonal anti-afamin antibody N14 with human afamin and obtained a stoichiometric complex. Subsequent results showed sufficient expression of various partially or nonglycosylated forms of rhAFM in HEK293T and CHO cells and revealed that glycosylation is not necessary for expression and secretion.

In search of potential early biomarkers for timely prediction of gestational diabetes mellitus (GDM), we focused on afamin, a vitamin E–binding protein in human plasma.. Afamin plays a role in anti-apoptotic cellular processes related to oxidative stress and is associated with insulin resistance and other features of metabolic syndrome. During uncomplicated pregnancy its serum concentrations increase linearly. The aim of this study was to investigate the suitability of afamin as early marker for predicting GDM.

•Early predictive serum biomarkers for pregnancy complications are missing.•First trimester afamin concentrations predict pre-eclampsia and gestational diabetes mellitus.•Potential clinical implications for appropriate treatment of these conditions.

Oxidative stress is involved in the pathogenesis of hypertensive disorders such as preeclampsia (PE) and associated with the human vitamin E-binding protein afamin. The aim of this study was, therefore, to analyse afamin in the first trimester of patients developing PE later in pregnancy and in control subjects without pregnancy complications.

Oxidativer Stress stellt einen Risikofaktor für Herz-Kreislauf-Erkrankungen und das metabolische Syndrom dar, ist mit Adipositas, Insulinresistenz und Schwangerschaftskomplikationen assoziiert. Vitamin E ist ein bedeutsames Antioxidans und wird im Plasma an sein Bindeprotein Afamin gebunden. Erhöhte Afaminserumspiegel konnten bei Insulinresistenz, Adipositas, Hypertension und Hyperlipidämie nachgewiesen werden. Afamin könnte somit einen Indikator für oxidativen Stress und damit assoziierte Schwangerschaftskomplikationen darstellen.