Sandra Freitag-Wolf

Dr. Sandra Freitag-Wolf

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Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 May 2019 in Nature Genetics
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LSLifelines Cohort Study
Lifelines Cohort Study
MWMatthias Wuttke
Matthias Wuttke
VPV. A. Million Veteran Program
V. A. Million Veteran Program
YLYong Li
Yong Li
MLMan Li
Man Li
CPCristian Pattaro
Cristian Pattaro
Chronic kidney disease (CKD) is responsible for a public health burden with multi-systemic complications. Through trans-ancestry meta-analysis of genome-wide association studies of estimated glomerular filtration rate (eGFR) and independent replication (n = 1,046,070), we identified 264 associated loci (166 new). Of these, 147 were likely to be relevant for kidney function on the basis of associations with the alternative kidney function marker blood urea nitrogen (n = 416,178). Pathway and enrichment analyses, including mouse models with renal phenotypes, support the kidney as the main target organ. A genetic risk score for lower eGFR was associated with clinically diagnosed CKD in 452,264 independent individuals. Colocalization analyses of associations with eGFR among 783,978 European-ancestry individuals and gene expression across 46 human tissues, including tubulo-interstitial and glomerular kidney compartments, identified 17 genes differentially expressed in kidney. Fine-mapping highlighted missense driver variants in 11 genes and kidney-specific regulatory variants. These results provide a comprehensive priority list of molecular targets for translational research.

11 September 2019 in Nature Communications
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ATAlexander Teumer
Alexander Teumer
YLYong Li
Yong Li
SGSahar Ghasemi
Sahar Ghasemi
BPBram Peter Prins
Bram Peter Prins
MWMatthias Wuttke
Matthias Wuttke
AKAnna Köttgen
Anna Köttgen
Increased levels of the urinary albumin-to-creatinine ratio (UACR) are associated with higher risk of kidney disease progression and cardiovascular events, but underlying mechanisms are incompletely understood. Here, we conduct trans-ethnic (n = 564,257) and European-ancestry specific meta-analyses of genome-wide association studies of UACR, including ancestry- and diabetes-specific analyses, and identify 68 UACR-associated loci. Genetic correlation analyses and risk score associations in an independent electronic medical records database (n = 192,868) reveal connections with proteinuria, hyperlipidemia, gout, and hypertension. Fine-mapping and trans-Omics analyses with gene expression in 47 tissues and plasma protein levels implicate genes potentially operating through differential expression in kidney (including TGFB1, MUC1, PRKCI, and OAF), and allow coupling of UACR associations to altered plasma OAF concentrations. Knockdown of OAF and PRKCI orthologs in Drosophila nephrocytes reduces albumin endocytosis. Silencing fly PRKCI further impairs slit diaphragm formation. These results generate a priority list of genes and pathways for translational research to reduce albuminuria.

22 November 2006 in BMC Gastroenterology
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CSClemens Schafmayer
Clemens Schafmayer
JHJürgen Hartleb
Jürgen Hartleb
JTJürgen Tepel
Jürgen Tepel
SAStefan Albers
Stefan Albers
SFSandra Freitag-Wolf
Sandra Freitag-Wolf
JHJochen Hampe
Jochen Hampe
Background: Gallstones represent a prevalent and costly health problem. The changing epidemiology and the emerging non-surgical interventions for gallstone disease necessitate the definition of target populations for future therapies. This study aimed to define patterns of gallstone composition and identify demographic predictors of gallstone composition in a large sample of symptomatic gallstones from Northern Germany. Methods: One thousand and seventy-four post-cholecystectomy gallstone specimens were obtained. Demographic and clinical information was provided by questionnaire (N = 1025 independent individuals with complete information). Two samples from each gallstone were analyzed using Fourier transformed infrared spectrometry. Results: The most prevalent substance was cholesterol, which was detected in 95.0% of gallstone specimens. Bilirubin and bilirubinate were present in 30.0% and calcium was detected in 10.0% of the spectra. Ninety-two percent of measurements from the same stone yielded the same "main" substances, indicating a homogenous stone composition in most cases. Female sex and higher body mass index (BMI) were associated with the presence of cholesterol as a main substance in the gallstones (p < 0.001). Conclusion: The changing epidemiology of gallstone disease is reflected by a marked shift in stone composition: Only two percent of stones in this study were pigment stones as compared to 91% percent of stones containing cholesterol as a main substance. Obese individuals from Germany with a BMI > 30 kg/m2 have in 95% cholesterol-dominant gallstones and represent a potential target population for non-surgical interventions for the prevention or treatment of cholesterol stones.

9 June 2021 in European Heart Journal
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Achille AnselmoAchille Anselmo
Achille Anselmo
DFDerk Frank
Derk Frank
LPLaura Papa
Laura Papa
CAChiara Viviani Anselmi
Chiara Viviani Anselmi
EPElisa Di Pasquale
Elisa Di Pasquale
Gerolama CondorelliGerolama Condorelli
Gerolama Condorelli
Increased shedding of extracellular vesicles (EVs)—small, lipid bilayer-delimited particles with a role in paracrine signalling—has been associated with human pathologies, e.g. atherosclerosis, but whether this is true for cardiac diseases is unknown. Here, we used the surface antigen CD172a as a specific marker of cardiomyocyte (CM)-derived EVs; the CM origin of CD172a+ EVs was supported by their content of cardiac-specific proteins and heart-enriched microRNAs. We found that patients with aortic stenosis, ischaemic heart disease, or cardiomyopathy had higher circulating CD172a+ cardiac EV counts than did healthy subjects. Cellular stress was a major determinant of EV release from CMs, with hypoxia increasing shedding in in vitro and in vivo experiments. At the functional level, EVs isolated from the supernatant of CMs derived from human-induced pluripotent stem cells and cultured in a hypoxic atmosphere elicited a positive inotropic response in unstressed CMs, an effect we found to be dependent on an increase in the number of EVs expressing ceramide on their surface. Of potential clinical relevance, aortic stenosis patients with the highest counts of circulating cardiac CD172a+ EVs had a more favourable prognosis for transcatheter aortic valve replacement than those with lower counts. We identified circulating CD172a+ EVs as cardiac derived, showing their release and function and providing evidence for their prognostic potential in aortic stenosis patients. Cermaides contained in CD172+ extracellular vesicles that are released by cardiomyocytes upon hypoxic stress may exert a positive inotropic effect on unstressed areas of the heart (top), and aortic stenosis patients with higher counts of these vesicles have better prognosis for valve replacement (bottom).

7 October 2021 in Biology
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RFRegina Fölster-Holst
Regina Fölster-Holst
RRRahel Reimer
Rahel Reimer
CNClaudia Neumann
Claudia Neumann
EPEhrhardt Proksch
Ehrhardt Proksch
ERElke Rodríguez
Elke Rodríguez
SFSandra Freitag-Wolf
Sandra Freitag-Wolf
A deficient epidermal barrier is a key feature of atopic dermatitis (AD) and comprises altered lipid and protein content and composition of the stratum corneum resulting in disturbed water balance. Clinically, eczematous lesions on dry skin and pruritus develop. Pruritic nodules occur in prurigo nodularis (PN), another chronic skin disease, which can be associated with atopy. We aimed at comparing the three clinical pictures, classic AD, atopic prurigo (AP), and non-atopic PN, to healthy controls regarding the epidermal barrier. We determined clinical parameters and performed biophysical measurements, histology/immunohistochemistry, electron microscopy, and molecular biological analysis. We found distinctively elevated clinical scores, reduced hydration and increased transepidermal water loss, epidermal hyperplasia and inflammation reduced filaggrin and increased loricrin and involucrin expression, as well as reduced intercellular lipid lamellae in all three disease groups. These findings show a severe disruption in epidermal barrier structure and function in all three disorders so that epidermal barrier impairment is now proven not only for AD but also for PN.

18 August 2021 in Journal of Clinical Periodontology
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SFSandra Freitag-Wolf
Sandra Freitag-Wolf
MMMatthias Munz
Matthias Munz
OJOlaf Junge
Olaf Junge
CGChristian Graetz
Christian Graetz
YJYvonne Jockel-Schneider
Yvonne Jockel-Schneider
ASArne S Schaefer
Arne S Schaefer
Aims: Various studies have reported that young European women are more likely to develop early‐onset periodontitis compared to men. A potential explanation for the observed variations in sex and age of disease onset is the natural genetic variation within the autosomal genomes. We hypothesized that genotype‐by‐sex (G × S) interactions contribute to the increased prevalence and severity.Materials and methods: Using the case‐only design, we tested for differences in genetic effects between men and women in 896 North‐West European early‐onset cases, using imputed genotypes from the OmniExpress genotyping array. Population‐representative 6823 controls were used to verify that the interacting variables G and S were uncorrelated in the general population.Results: In total, 20 loci indicated G × S associations (P < 0.0005), 3 of which were previously suggested as risk genes for periodontitis (ABLIM2, CDH13, and NELL1). We also found independent G × S interactions of the related gene paralogs MACROD1/FLRT1 (chr11) and MACROD2/FLRT3 (chr20). G × S‐associated SNPs at CPEB4, CDH13, MACROD1, and MECOM were genome‐wide‐associated with heel bone mineral density (CPEB4, MECOM), waist‐to‐hip ratio (CPEB4, MACROD1), and blood pressure (CPEB4, CDH13).Conclusions: Our results indicate that natural genetic variation affects the different heritability of periodontitis among sexes and suggest genes that contribute to inter‐sex phenotypic variation in early‐onset periodontitis.