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1.
Clin Genet ; 104(3): 334-343, 2023 09.
Article in English | MEDLINE | ID: mdl-37417318

ABSTRACT

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.


Subject(s)
Hypercholesterolemia , Hyperlipoproteinemia Type II , Humans , Hypercholesterolemia/diagnosis , Hypercholesterolemia/genetics , Hypercholesterolemia/complications , Cholesterol, LDL/genetics , Hyperlipoproteinemia Type II/genetics , Risk Factors , Cholesterol , Risk Assessment , Receptors, LDL/genetics
2.
Atherosclerosis ; 355: 15-29, 2022 08.
Article in English | MEDLINE | ID: mdl-35870306

ABSTRACT

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 approaches 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≤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.


Subject(s)
Hyperlipoproteinemia Type II , Cost-Benefit Analysis , Genetic Testing/methods , Humans , Hyperlipoproteinemia Type II/diagnosis , Hyperlipoproteinemia Type II/genetics , Infant, Newborn , Mass Screening/methods , Quality-Adjusted Life Years
3.
Dtsch Med Wochenschr ; 147(10): e50-e61, 2022 04.
Article in German | MEDLINE | ID: mdl-35545064

ABSTRACT

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.


Subject(s)
Hyperlipoproteinemia Type II , Hyperlipoproteinemias , Xanthomatosis , Humans , Hyperlipoproteinemia Type II/genetics , Hyperlipoproteinemias/complications , Lipid Metabolism/genetics , Triglycerides , Xanthomatosis/complications , Xanthomatosis/genetics
4.
Clin Chem Lab Med ; 60(2): 243-251, 2022 01 27.
Article in English | MEDLINE | ID: mdl-34850615

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.


Subject(s)
Carrier Proteins , Glycoproteins , Non-alcoholic Fatty Liver Disease , Serum Albumin, Human , Adult , Austria/epidemiology , Carrier Proteins/blood , Female , Finland/epidemiology , Glycoproteins/blood , Humans , Incidence , Male , Non-alcoholic Fatty Liver Disease/blood , Non-alcoholic Fatty Liver Disease/diagnosis , Non-alcoholic Fatty Liver Disease/epidemiology , Prevalence , Risk Factors
5.
Front Endocrinol (Lausanne) ; 12: 670425, 2021.
Article in English | MEDLINE | ID: mdl-34603196

ABSTRACT

Aim: Afamin 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. Methods: We 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). Results: Prediabetes 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. Conclusions: Subjects 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.


Subject(s)
Adiposity , Biomarkers/blood , Carrier Proteins/blood , Diabetes Mellitus, Type 2/diagnosis , Fatty Liver/diagnosis , Glycoproteins/blood , Obesity/physiopathology , Prediabetic State/diagnosis , Adult , Body Mass Index , Cross-Sectional Studies , Diabetes Mellitus, Type 2/blood , Fatty Liver/blood , Female , Follow-Up Studies , Humans , Insulin Resistance , Lipid Metabolism , Male , Prediabetic State/blood , Prognosis , Serum Albumin, Human
6.
Atherosclerosis ; 319: 108-117, 2021 02.
Article in English | MEDLINE | ID: mdl-33508743

ABSTRACT

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 pre- and 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 × 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 × 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.


Subject(s)
Hyperlipoproteinemia Type II , Proprotein Convertase 9 , Austria , Belgium , Child , Czech Republic/epidemiology , DNA Mutational Analysis , Europe , Greece , Humans , Hyperlipoproteinemia Type II/diagnosis , Hyperlipoproteinemia Type II/epidemiology , Hyperlipoproteinemia Type II/genetics , Lipids , Mutation , Netherlands/epidemiology , Norway , Portugal , Proprotein Convertase 9/genetics , Receptors, LDL/genetics
7.
Atherosclerosis ; 292: 178-187, 2020 01.
Article in English | MEDLINE | ID: mdl-31809987

ABSTRACT

BACKGROUND AND AIMS: For children with heterozygous familial hypercholesterolaemia (HeFH), European guidelines recommend consideration of statin therapy by age 8-10 years for those with a low density lipoprotein cholesterol (LDL-C) >3.5 mmol/l, and dietary and lifestyle advice. Here we compare the characteristics and lipid levels in HeFH children from Norway, UK, Netherlands, Belgium, Czech Republic, Austria, Portugal and Greece. METHODS: Fully-anonymized data were analysed at the London centre. Differences in registration and on treatment characteristics were compared by standard statistical tests. RESULTS: Data was obtained from 3064 children. The median age at diagnosis differed significantly between countries (range 3-11 years) reflecting differences in diagnostic strategies. Mean (SD) LDL-C at diagnosis was 5.70 (±1.4) mmol/l, with 88% having LDL-C>4.0 mmol/l. The proportion of children older than 10 years at follow-up who were receiving statins varied significantly (99% in Greece, 56% in UK), as did the proportion taking Ezetimibe (0% in UK, 78% in Greece). Overall, treatment reduced LDL-C by between 28 and 57%, however, in those >10 years, 23% of on-treatment children still had LDL-C>3.5 mmol/l and 66% of those not on a statin had LDL-C>3.5 mmol/l. CONCLUSIONS: The age of HeFH diagnosis in children varies significantly across 8 countries, as does the proportion of those >10 years being treated with statin and/or ezetimibe. Approximately a quarter of the treated children and almost three quarters of the untreated children older than 10 years still have LDL-C concentrations over 3.5 mmol/l. These data suggest that many children with FH are not receiving the full potential benefit of early identification and appropriate lipid-lowering treatment according to recommendations.


Subject(s)
Hydroxymethylglutaryl-CoA Reductase Inhibitors/therapeutic use , Hyperlipoproteinemia Type II/diagnosis , Hyperlipoproteinemia Type II/drug therapy , Child , Child, Preschool , Cholesterol, LDL/blood , Europe , Female , Heterozygote , Humans , Hyperlipoproteinemia Type II/blood , Hyperlipoproteinemia Type II/genetics , Male , Retrospective Studies
8.
Atherosclerosis ; 289: 206-213, 2019 10.
Article in English | MEDLINE | ID: mdl-31493849

ABSTRACT

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.


Subject(s)
Cardiovascular Diseases/blood , Clinical Laboratory Techniques/standards , Immunoassay/methods , Lipoprotein(a)/blood , Reagent Kits, Diagnostic/standards , Calibration , Clinical Laboratory Techniques/instrumentation , Humans , Immunoturbidimetry , Least-Squares Analysis , Myocardial Infarction/blood , Nephelometry and Turbidimetry , Phenotype , Reproducibility of Results , Risk Factors
9.
Endocr Connect ; 8(5): 616-624, 2019 May 01.
Article in English | MEDLINE | ID: mdl-30991357

ABSTRACT

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.

10.
Arch Gynecol Obstet ; 298(5): 1009-1016, 2018 11.
Article in English | MEDLINE | ID: mdl-30220025

ABSTRACT

PURPOSE: 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. METHODS: In this retrospective study, 137 serum samples from the first trimester of pregnancy were analysed in a case-control study design. 39 patients developed PE (10 patients with early-onset and 29 patients with late onset disease) and 98 women had an uncomplicated pregnancy. Mann-Whitney U test, t test, logistic regression and ROC analyses were performed for statistical evaluation. RESULTS: Pregnant women developing PE presented with higher afamin concentrations in the first trimester [median 101.81 mg/L; interquartile range (IQR) 88.94-113.26] compared to subjects with uncomplicated pregnancy (median 86.40; IQR 75.26-96.92; p < 0.001). After adjusting for confounders, the odds ratio per afamin standard deviation was 1.60 (95% CI: 1.04-2.58; p = 0.04). An afamin threshold concentration of 87.8 mg/L exhibited the best sensitivity (79.5%) and specificity (57.1%) in predicting PE. Subgroup analysis of early- and late-onset disease resulted in substantially higher afamin concentrations in women with developing late-onset PE compared to controls (p < 0.001) with an odds ratio per afamin standard deviation of 1.62 (95% CI: 0.98-2.70; p = 0.06). CONCLUSIONS: Serum afamin concentrations are elevated in the first trimester among patients developing PE compared to controls. Substantial differences were observed mainly among patients with late-onset PE.


Subject(s)
Carrier Proteins/blood , Glycoproteins/blood , Pre-Eclampsia/blood , Adult , Biomarkers/blood , Case-Control Studies , Female , Humans , Odds Ratio , Pregnancy , Pregnancy Trimester, First/blood , Retrospective Studies , Serum Albumin, Human
11.
Reprod Biol Endocrinol ; 16(1): 30, 2018 Mar 27.
Article in English | MEDLINE | ID: mdl-29587878

ABSTRACT

BACKGROUND: 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. METHODS: In a first-trimester cohort from a prospective observational study of adverse pregnancy outcomes we secondarily analyzed afamin concentrations in 59 patients diagnosed with GDM and 51 controls. Additionally, afamin concentrations were cross-sectionally examined in a mid-trimester cohort of 105 women and compared with results from a simultaneously performed oral glucose tolerance test (OGTT). Subgroup analysis comparing patients treated with either insulin (iGDM) or dietary intervention (dGDM) was performed in both cohorts. Patients were recruited at the University Hospital Essen, Germany, between 2003 and 2016. RESULTS: Results were adjusted for body-mass-index (BMI) and gestational age. First and mid-trimester cohorts yielded significantly elevated afamin concentrations in patients with pathological OGTT compared to patients without GDM (first trimester cohort: mean, 113.4 mg/l; 95% CI, 106.4-120.5 mg/l and 87.2 mg/l; 95% CI, 79.7-94.7 mg/l; mid-trimester cohort: mean, 182.9 mg/l; 95% CI, 169.6-196.2 mg/l and 157.3 mg/l; 95% CI, 149.1-165.4 mg/l, respectively). In the first-trimester cohort, patients developing iGDM later in pregnancy presented with significantly higher afamin concentrations compared to patients developing dGDM and compared to patients without GDM. In the mid-trimester cohort, mean concentrations of afamin differed significantly between patients with dGDM compared to controls and between patients with iGDM and controls. Patients with iGDM showed only slightly higher afamin levels compared to patients with dGDM. CONCLUSION: Afamin may serve as a new early biomarker for pathological glucose metabolism during pregnancy. Further research is needed to determine afamin's concentrations during pregnancy, its predictive value for early detection of pregnancies at high risk to develop GDM and its diagnostic role during the second trimester.


Subject(s)
Biomarkers/blood , Carrier Proteins/blood , Diabetes, Gestational/blood , Glycoproteins/blood , Adult , Diabetes, Gestational/diet therapy , Diabetes, Gestational/drug therapy , Female , Germany , Gestational Age , Glucose Tolerance Test , Humans , Insulin/therapeutic use , Pilot Projects , Pregnancy , Pregnancy Trimester, First/blood , Pregnancy Trimester, Second , Prospective Studies , Serum Albumin, Human
12.
J Proteome Res ; 17(3): 1269-1277, 2018 03 02.
Article in English | MEDLINE | ID: mdl-29441788

ABSTRACT

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.


Subject(s)
Antibodies, Monoclonal/chemistry , Antigen-Antibody Complex/chemistry , Carrier Proteins/chemistry , Glycoproteins/chemistry , Immunoglobulin Fab Fragments/chemistry , Protein Processing, Post-Translational , Serum Albumin, Human/chemistry , Amino Acid Sequence , Animals , Antibodies, Monoclonal/metabolism , Antigen-Antibody Complex/metabolism , CHO Cells , Carrier Proteins/genetics , Carrier Proteins/metabolism , Cloning, Molecular , Cricetulus , Escherichia coli/genetics , Escherichia coli/metabolism , Gene Expression , Genetic Vectors/chemistry , Genetic Vectors/metabolism , Glycoproteins/genetics , Glycoproteins/metabolism , Glycosylation , HEK293 Cells , Humans , Immunoglobulin Fab Fragments/metabolism , Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase/chemistry , Polysaccharides/chemistry , Polysaccharides/metabolism , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Serum Albumin, Human/genetics , Serum Albumin, Human/metabolism
13.
Placenta ; 62: 9-15, 2018 02.
Article in English | MEDLINE | ID: mdl-29405972

ABSTRACT

OBJECTIVE: Aim of the study was to assess the correlation of first trimester serum afamin levels with three-dimensional placental bed vascularization in pregnant women and its prognostic value for predicting pre-eclampsia and future fetal and maternal complications during pregnancy. METHODS: In this nested case-control study all pregnant women registered for delivery during a period of 3 years were routinely screened in the first trimester. Serum afamin levels were assessed in 764 women and correlated to 5 pregnancy outcome groups: gestational hypertension (n = 76), pre-eclampsia (n = 33), intrauterine growth restriction (n = 91), pre-term birth (n = 39), gestational diabetes mellitus (n = 170); In addition, measurements of first trimester myometrial vascularization index were performed and, in combination with afamin tested as a possible screening method to detect women at-risk for the development of adverse complications in low-risk pregnancies at the time of the first trimester. RESULTS: The results showed significantly higher serum afamin levels in women with pre-eclampsia (P<.05) and gestational diabetes mellitus (P<.05) compared to healthy pregnant women. There was no significant difference in serum afamin levels between all other pregnancy outcome groups and healthy controls. In women developing pre-eclampsia during pregnancy, afamin (OR = 1.0197, P < .05) and myometrial vascular index (OR = 0.9235, P < .001) were verified to have a significant prognostic value. Detection of pre-eclampsia in first trimester screening by a combination of afamin and myometrial vascular index performed best (AUC = 0.818). DISCUSSION: Hence, first trimester screening for pre-eclampsia could be provided by a combination of afamin and placental bed vascularization. Moreover, the combination of first trimester serum afamin levels with BMI could provide a possible screening for gestational diabetes mellitus.


Subject(s)
Carrier Proteins/blood , Diabetes, Gestational/diagnosis , Glycoproteins/blood , Neovascularization, Pathologic/diagnostic imaging , Placenta/blood supply , Pre-Eclampsia/diagnosis , Adult , Biomarkers/blood , Case-Control Studies , Diabetes, Gestational/blood , Female , Humans , Placenta/diagnostic imaging , Pre-Eclampsia/blood , Pregnancy , Pregnancy Outcome , Pregnancy Trimester, First , Retrospective Studies , Serum Albumin, Human , Ultrasonography, Prenatal , Young Adult
14.
Clin Chim Acta ; 476: 160-166, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29191735

ABSTRACT

OBJECTIVE: Aim of this study was to assess the prognostic capability of afamin to predict pregnancy complications. METHOD: First-trimester screening was consecutively performed in 4948 pregnant women, of whom 474 women developed pregnancy complications [gestational hypertension (n=84), pre-eclampsia (n=30), intrauterine growth restriction (n=107), preterm birth (n=44), and gestational diabetes mellitus (n=209)]. To each woman with pregnancy complications an uncomplicated pregnancy was matched for body mass index. Afamin serum concentrations were measured in 948 pregnant women at the first-trimester screening. RESULTS: Median afamin concentrations were significantly higher in women developing pre-eclampsia or gestational diabetes mellitus when compared to women with uncomplicated pregnancies (76mg/L vs. 65mg/L, p=0.001 and 80mg/L vs. 69mg/L, p<0.001). There was no difference in median afamin values between all other pregnancy complications and their matched controls. Increased afamin (i.e. >65mg/L) was a strong and independent predictor for the development of pre-eclampsia (risk ratio, 24.58; 95%CI, 2.82-214.12; p=0.004) as well as gestational diabetes mellitus (risk ratio, 2.07; 95%CI, 1.33-3.22; p=0.001). CONCLUSION: In this large nested case-control study increased afamin concentrations were a strong and independent predictor for pre-eclampsia and gestational diabetes mellitus, suggesting a potential role of afamin as predictive marker for pregnancy-related metabolic disorders.


Subject(s)
Carrier Proteins/blood , Diabetes, Gestational/blood , Glycoproteins/blood , Pre-Eclampsia/blood , Pregnancy Trimester, First/blood , Adult , Case-Control Studies , Female , Humans , Pregnancy , Pregnancy Complications/blood , Serum Albumin, Human , Young Adult
15.
Structure ; 25(12): 1907-1915.e5, 2017 12 05.
Article in English | MEDLINE | ID: mdl-29153507

ABSTRACT

Afamin, a human plasma glycoprotein and putative transporter of hydrophobic molecules, has been shown to act as extracellular chaperone for poorly soluble, acylated Wnt proteins, forming a stable, soluble complex with functioning Wnt proteins. The 2.1-Å crystal structure of glycosylated human afamin reveals an almost exclusively hydrophobic binding cleft capable of harboring large hydrophobic moieties. Lipid analysis confirms the presence of lipids, and density in the primary binding pocket of afamin was modeled as palmitoleic acid, presenting the native O-acylation on serine 209 in human Wnt3a. The modeled complex between the experimental afamin structure and a Wnt3a homology model based on the XWnt8-Fz8-CRD fragment complex crystal structure is compelling, with favorable interactions comparable with the crystal structure complex. Afamin readily accommodates the conserved palmitoylated serine 209 of Wnt3a, providing a structural basis how afamin solubilizes hydrophobic and poorly soluble Wnt proteins.


Subject(s)
Carrier Proteins/chemistry , Glycoproteins/chemistry , Serum Albumin, Human/chemistry , Wnt3A Protein/metabolism , Acetylation , Binding Sites , Carrier Proteins/metabolism , Glycoproteins/metabolism , Humans , Lipoylation , Molecular Docking Simulation , Protein Binding , Protein Processing, Post-Translational , Protein Stability , Protein Transport , Serum Albumin, Human/metabolism , Wnt3A Protein/chemistry
16.
Diabetes Care ; 40(10): 1386-1393, 2017 10.
Article in English | MEDLINE | ID: mdl-28877915

ABSTRACT

OBJECTIVE: The human vitamin E-binding glycoprotein afamin is primarily expressed in the liver and has been associated with prevalent and incident metabolic syndrome. These data were in line with observations in transgenic mice. We thus investigated whether afamin concentrations are associated with prediabetes, type 2 diabetes, and insulin resistance (IR). RESEARCH DESIGN AND METHODS: Individual-level baseline (n = 20,136) and follow-up data (n = 14,017) of eight prospective cohort studies were investigated. Study-level data were combined using random-effects meta-analyses. Main outcomes were prevalent and incident type 2 diabetes, prediabetes, and IR. Discrimination and reclassification of participants was analyzed for incident type 2 diabetes. RESULTS: Mean afamin concentrations between studies ranged from 61 to 73 mg/L. The eight studies included 1,398 prevalent and 585 incident cases of type 2 diabetes. Each increase of afamin by 10 mg/L was associated with prevalent type 2 diabetes (odds ratio [OR] 1.19 [95% CI 1.12-1.26], P = 5.96 × 10-8). Afamin was positively associated with IR assessed by HOMA-IR (ß 0.110 [95% CI 0.089-0.132], P = 1.37 × 10-23). Most importantly, afamin measured at baseline was an independent predictor for 585 incident cases of type 2 diabetes (OR 1.30 [95% CI 1.23-1.38], P = 3.53 × 10-19) and showed a significant and valuable gain in risk classification accuracy when added to this extended adjustment model. CONCLUSIONS: This pooled analysis in >20,000 individuals showed that afamin is strongly associated with IR, prevalence, and incidence of type 2 diabetes independent of major metabolic risk factors or parameters. Afamin might be a promising novel marker for the identification of individuals at high risk for the development of type 2 diabetes.


Subject(s)
Carrier Proteins/blood , Diabetes Mellitus, Type 2/epidemiology , Glycoproteins/blood , Metabolic Syndrome/epidemiology , Prediabetic State/epidemiology , Adult , Aged , Aged, 80 and over , Biomarkers/blood , Body Mass Index , Cholesterol/blood , Diabetes Mellitus, Type 2/blood , Female , Follow-Up Studies , Glycated Hemoglobin/metabolism , Humans , Incidence , Insulin Resistance , Male , Metabolic Syndrome/blood , Middle Aged , Prediabetic State/blood , Prevalence , Prospective Studies , Risk Factors , Serum Albumin, Human , Triglycerides/blood
17.
Acta Crystallogr D Struct Biol ; 72(Pt 12): 1267-1280, 2016 12 01.
Article in English | MEDLINE | ID: mdl-27917827

ABSTRACT

The monoclonal antibody N14 is used as a detection antibody in ELISA kits for the human glycoprotein afamin, a member of the albumin family, which has recently gained interest in the capture and stabilization of Wnt signalling proteins, and for its role in metabolic syndrome and papillary thyroid carcinoma. As a rare occurrence, the N14 Fab is N-glycosylated at Asn26L at the onset of the VL1 antigen-binding loop, with the α-1-6 core fucosylated complex glycan facing out of the L1 complementarity-determining region. The crystal structures of two non-apparent (pseudo) isomorphous crystals of the N14 Fab were analyzed, which differ significantly in the elbow angles, thereby cautioning against the overinterpretation of domain movements upon antigen binding. In addition, the map quality at 1.9 Šresolution was sufficient to crystallographically re-sequence the variable VL and VH domains and to detect discrepancies in the hybridoma-derived sequence. Finally, a conservatively refined parsimonious model is presented and its statistics are compared with those from a less conservatively built model that has been modelled more enthusiastically. Improvements to the PDB validation reports affecting ligands, clashscore and buried surface calculations are suggested.


Subject(s)
Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Carrier Proteins/immunology , Glycoproteins/immunology , Immunoglobulin Fab Fragments/chemistry , Immunoglobulin Fab Fragments/immunology , Serum Albumin/immunology , Animals , Antigen-Antibody Complex , Complementarity Determining Regions , Crystallography, X-Ray , Glycosylation , Humans , Immunoglobulin Variable Region/chemistry , Immunoglobulin Variable Region/immunology , Mice , Models, Molecular , Serum Albumin, Human
18.
Atheroscler Suppl ; 22: 1-32, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27939304

ABSTRACT

BACKGROUND: The potential for global collaborations to better inform public health policy regarding major non-communicable diseases has been successfully demonstrated by several large-scale international consortia. However, the true public health impact of familial hypercholesterolaemia (FH), a common genetic disorder associated with premature cardiovascular disease, is yet to be reliably ascertained using similar approaches. The European Atherosclerosis Society FH Studies Collaboration (EAS FHSC) is a new initiative of international stakeholders which will help establish a global FH registry to generate large-scale, robust data on the burden of FH worldwide. METHODS: The EAS FHSC will maximise the potential exploitation of currently available and future FH data (retrospective and prospective) by bringing together regional/national/international data sources with access to individuals with a clinical and/or genetic diagnosis of heterozygous or homozygous FH. A novel bespoke electronic platform and FH Data Warehouse will be developed to allow secure data sharing, validation, cleaning, pooling, harmonisation and analysis irrespective of the source or format. Standard statistical procedures will allow us to investigate cross-sectional associations, patterns of real-world practice, trends over time, and analyse risk and outcomes (e.g. cardiovascular outcomes, all-cause death), accounting for potential confounders and subgroup effects. CONCLUSIONS: The EAS FHSC represents an excellent opportunity to integrate individual efforts across the world to tackle the global burden of FH. The information garnered from the registry will help reduce gaps in knowledge, inform best practices, assist in clinical trials design, support clinical guidelines and policies development, and ultimately improve the care of FH patients.


Subject(s)
Delivery of Health Care, Integrated , Hyperlipoproteinemia Type II/therapy , International Cooperation , Professional Practice Gaps , Registries , Research Design , Access to Information , Cooperative Behavior , Data Mining , Delivery of Health Care, Integrated/organization & administration , Humans , Hyperlipoproteinemia Type II/diagnosis , Hyperlipoproteinemia Type II/genetics , Hyperlipoproteinemia Type II/mortality , Information Storage and Retrieval , Organizational Objectives , Treatment Outcome
20.
Am J Cardiovasc Drugs ; 16(5): 323-36, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27430233

ABSTRACT

Decreasing low-density lipoprotein cholesterol (LDL-C) is one of the few established and proven principles for the prevention and treatment of atherosclerosis. The higher the individual cardiovascular risk, the higher the benefit of lipid-lowering pharmacotherapy. Therefore, treatment options are chosen based on a patient's total cardiovascular risk. The latter depends not only on the levels of LDL-C but also on the presence of cardiovascular disease (CVD) and on the number and severity of other risk factors. Current guidelines recommend the lowering of LDL-C to 115 mg/dl (3 mmol/l) in patients with low and moderate risk. The LDL-C treatment target is <100 mg/dl (2.6 mmol/l) for patients at high risk and <70 mg/dl (1.8 mmol/l) for patients at very high risk. Although lifestyle measures remain a fundamental part of treatment, many patients require drug therapy to achieve their LDL-C targets. Statins are the drugs of choice, with other options including ezetimibe and the newly available monoclonal antibodies against PCSK9 (proprotein convertase subtilisin/kexin type 9). In some cases, bile acid-binding sequestrants and fibrates can also be considered. Nicotinic acid is no longer available in Germany. PCSK9 antibodies decrease LDL-C about 50-60 % and are well tolerated. Their effects on clinical endpoints are being investigated in large randomized trials. The aim of the present review is to summarize the current guidelines and treatment options for hypercholesterolemia. Moreover, we provide an appraisal of PCSK9 antibodies and propose their use in selected patient populations, particularly in those at very high cardiovascular risk whose LDL-C levels under maximally tolerated lipid-lowering therapy are significantly over their treatment target.


Subject(s)
Anticholesteremic Agents/therapeutic use , Cholesterol, LDL/metabolism , Hypercholesterolemia/drug therapy , Hypercholesterolemia/metabolism , Antibodies, Monoclonal/therapeutic use , Cardiovascular Diseases/blood , Cardiovascular Diseases/metabolism , Cardiovascular Diseases/prevention & control , Cholesterol, LDL/blood , Germany , Humans , Hypercholesterolemia/blood , Proprotein Convertase 9/metabolism , Randomized Controlled Trials as Topic , Risk Factors
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