Gerhard Liebisch

Gerhard Liebisch
University Hospital Regensburg | Uni Regensburg · Klinische Chemie und Laboratoriumsmedizin

46.37
 · 
PD Dr. rer. nat.

About

380
Publications
35,804
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10,148
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Introduction
Gerhard Liebisch currently works at the Klinische Chemie und Laboratoriumsmedizin , University Hospital Regensburg. Gerhard does research in Clinical Chemistry, Analytical Chemistry with a focus on Lipidomics. Their current project is 'MyNewGut Project: Microbiome's influence on energy balance and brain development/function put into action to tackle diet-related diseases and behaviour.'
Research Experience
May 1999 - present
University Hospital Regensburg
Position

Publications

Publications (380)
Article
Nature provides an enormous diversity of lipid molecules that originate from various pathways. To gain insight into the metabolism and dynamics of lipid species, the application of stable isotope-labeled tracers combined with mass spectrometric analysis represents a perfect tool. This review provides an overview of strategies to track fatty acid, g...
Article
Compensation of matrix effects is the main obstacle to achieve accurate quantification in LC-MS/MS. Therefore, quantitative LC-MS/MS typically relies on addition of internal standards (ISs). Here, we present a systematic comparison of ISs from a routine LC-MS/MS method for bile acid (BA) analysis with a focus on tauro-conjugated. Both human serum b...
Article
Full-text available
There is a need for a standardized, practical annotation for structures of lipid species derived from mass spectrometric approaches, i.e., for high-throughput data obtained from instruments operating in either high- or low-resolution modes. This proposal is based on common, officially accepted terms, and builds upon the LIPID MAPS terminology. It a...
Article
Lipoproteins are of fundamental importance for the lipid transport and cardiovascular disease. The function and metabolism of lipoproteins is intimately linked to the biophysical properties of their surface lipids. Although a number of disease associations were found for lipid species in plasma, only a few studies reported lipid profiles of lipopro...
Article
Lipidomic analyses aim for absolute quantification of lipid species profiles in biological samples. In the past years, mass spectrometry (MS) methods based on high resolution accurate masses (HRAM) have increasingly been applied to identify and quantify lipid species on MS-level. This strategy requires consideration of isobaric overlaps which may a...
Preprint
MicroRNA-221-3p (miR-221-3p) is associated with both metabolic diseases and cancers. However, its role in terminal adipocyte differentiation, adipocyte lipid metabolism, and lipid signaling in human disease are uncharacterized. miR-221-3p or its inhibitor were transfected into differentiating or mature human adipocytes. Triglyceride (TG) content an...
Article
This study aimed to investigate the effects of a short-term (36h) fasting period combined with an acute bout of exercise on markers of immune function and inflammation in healthy human subjects. Fourteen moderately trained male subjects (aged 19-39 years) participated in a 36 hrs Fasting-Trial (FA-T) followed by an acute bout of moderate exercise (...
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Objectives: Imbalanced nutrition and obesity are risk factors for depression, a relationship that in rodents can be modeled by depression-like behavior in response to high-fat diet (HFD). In this work, we examined the role of the intestinal microbiota and the adipocytokine leptin as potential mediators of the effects of HFD to induce anhedonia-like...
Article
The intestinal microbiome plays an important role in human health and disease and fecal materials reflect the microbial activity. Thus, analysis of fecal metabolites provides insight in metabolic interactions between gut microbiota and host organism. In this work, we applied flow injection analysis coupled to Fourier transform mass spectrometry (FI...
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Background While the impact of metformin in hepatocytes leads to fatty acid (FA) oxidation and decreased lipogenesis, hepatic microRNAs (miRNAs) have been associated with fat overload and impaired metabolism, contributing to the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Methods We investigated the expression of hundreds of miRNAs...
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Background: The hypothesis was tested that insect meal (IM) as protein source influences intermediary metabolism of growing pigs. To test this, 30 male, 5-week-old crossbred pigs were randomly assigned to 3 groups of 10 pigs each with similar body weights (BW) and fed isonitrogenous diets either without (CON) or with 5% IM (IM5) or 10% IM (IM10) f...
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Mitotane is the only drug approved for the therapy of adrenocortical carcinoma (ACC). Its clinical use is limited by the occurrence of relapse during therapy. To investigate the underlying mechanisms in vitro, we here generated mitotane-resistant cell lines. After long-term pulsed treatment of HAC-15 human adrenocortical carcinoma cells with 70 µM...
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The tumor inhibitory potential of the highly active chemerin-156 isoform was described in orthotopic models of hepatocellular carcinoma (HCC). The majority of HCC arises in the fibrotic liver, which was not reproduced in these studies. Here, a potential therapeutic activity of chemerin-156 was evaluated in diethylnitrosamine (DEN)-induced liver can...
Article
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High-density lipoproteins (HDL) contain hundreds of lipid species and proteins and exert many potentially vasoprotective and anti-diabetogenic activities on cells. To resolve structure-function-disease relationships of HDL we characterized HDL of 51 healthy subjects and 98 patients with diabetes (T2DM), coronary heart disease (CHD), or both for pro...
Article
Background: Non-alcoholic steatohepatitis (NASH) is a common disease and feeding mice a methionine-choline-deficient (MCD) diet is a frequently used model to study its pathophysiology. Genetic and environmental factors influence NASH development and liver lipid content, which was studied herein using C57BL/6 J mice bred in two different animal fac...
Article
Lipids are essential for all facets of life. They play three major roles: energy metabolism, structural, and signaling. They are dynamic molecules strongly influenced by endogenous and exogenous factors including genetics, diet, age, lifestyle, drugs, disease and inflammation. As precision medicine starts to become mainstream, there is a huge burge...
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Low whole grain consumption is a risk factor for the development of non-communicable diseases such as type 2 diabetes. Dietary fiber and phytochemicals are bioactive grain compounds, which could be involved in mediating these beneficial effects. These compounds are not equally distributed in the wheat grain, but are enriched in the bran and aleuron...
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Background: Group VIA calcium-independent phospholipase A2 (iPla2β) regulates homeostasis and remodeling of phospholipids (PL). We previously showed that iPla2β−/− mice fed with a methionine-choline-deficient diet (MCD) exhibited exaggerated liver fibrosis. As iPla2β is located in the endoplasmic reticulum (ER), we investigated the mechanisms for t...
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Lipid species patterns are conserved within cells to maintain physicochemical properties of membranes and cellular functions. We present the lipidome, including sterols, glycerolipids (GLs), glycerophospholipids (GPLs), and sphingolipids (SLs), of primary ex vivo differentiated (I) white, (II) brite, and (III) brown adipocytes derived from primary...
Article
Modern mass spectrometric technologies provide quantitative readouts for a wide variety of lipid specimens. However, many studies do not report absolute lipid concentrations and differ vastly in methodologies, workflows and data presentation. Therefore, we encourage researchers to engage with the Lipidomics Standards Initiative to develop common st...
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Long-term consumption of dietary fiber is generally considered beneficial for weight management and metabolic health, but the results of interventions vary greatly depending on the type of dietary fibers involved. This study provides a comprehensive evaluation of the effects of a specific dietary fiber consisting of a wheat-bran extract enriched in...
Article
Rationale: Pulmonary alveolar proteinosis (PAP) is characterized by filling of the alveolar spaces by lipoprotein-rich material of ill-defined composition, and is caused by molecularly different and often rare diseases that occur from birth to old age.Objectives: To perform a quantitative lipidomic analysis of lipids and the surfactant proteins A,...
Article
Ezetimibe (EZE) and glucuronidated EZE (EZE‐Glu) differentially target Niemann‐Pick C1‐like 1 (NPC1L1) and CD13 (aminopeptidase‐N) to inhibit intestinal cholesterol absorption and cholesterol processing in other cells, although the precise molecular mechanisms are not fully elucidated. Cellular effects of EZE, EZE‐Glu, and the low‐absorbable EZE‐an...
Article
Background: Balanced composition of a well-functioning pulmonary surfactant is crucial and essential for normal breathing. Here, we explored whether the composition of lipids recovered by broncho-alveolar lavage (BAL) in children with cystic fibrosis (CF) differ from children with protracted bacterial bronchitis (PBB) and controls. We wanted to di...
Article
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Short chain fatty acids (SCFAs) are generated by the degradation and fermentation of complex carbohydrates, (i.e., dietary fiber) by the gut microbiota relevant for microbe–host communication. Here, we present a method for the quantification of SCFAs in fecal samples by liquid chromatography tandem mass spectrometry (LC-MS/MS) upon derivatization t...
Article
FATP4 expression is upregulated in acquired obesity and polymorphisms in the FATP4 gene are associated with increased blood triglycerides (TG). Since non‐alcoholic fatty liver disease (NAFLD) is a manifestation of obesity, it is of interest to understand how FATP4 upon fat overload mediates alterations of lipids that lead to pathogenesis of fatty l...
Article
The quantification of free cholesterol (FC) and cholesteryl ester (CE) in mammalian samples is of great interest for basic science and clinical lipidomics. Here, we evaluated the feasibility of direct flow injection analysis (FIA) coupled to elec-trospray ionization-high resolution mass spectrometry (ESI-HRMS) to quantify FC and CE in lipid extract...
Article
Group VIA calcium-independent phospholipase A2 (iPla2β) is among modifier genes of non-alcoholic fatty liver disease which leads to non-alcoholic steatohepatitis (NASH). Consistently, iPla2β deletion protects hepatic steatosis and obesity in genetic ob/ob and obese mice chronically fed with high-fat diet by replenishing the loss of hepatic phosphol...
Article
A defect of hepatic remodeling of phospholipids (PL) is seen in non-alcoholic fatty liver disease and steatohepatitis (NASH) indicating pivotal role of PL metabolism in this disease. The deletion of group VIA calcium-independent phospholipase A2 (iPla2β) protects ob/ob mice from hepatic steatosis (BBAlip 1861, 2016, 440–461), however its role in hi...
Article
Background & aims: Gut microbiota composition is linked to obesity and metabolic syndrome. The nutrients and doses required to modulate the gut microbiota towards beneficially influence components of the metabolic syndrome are unclear. This study aimed to investigate diet-induced effects on the gut microbiota and metabolic markers in overweight in...
Article
Scope : The hypothesis was tested that insect meal, which has a low methionine content, reduces the hepatic phosphatidylcholine (PC):phosphatidylethanolamine (PE) ratio, which is a critical determinant of hepatic lipid synthesis, by decreasing availability of the methionine metabolite S‐adenosylmethionine (SAM). Methods and results : Obese rats (n...
Article
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Phospholipids (PLs) possess the unique ability to contribute to synovial joint lubrication. The aim of our study was to determine for the first time the effect of dexamethasone and some adrenergic and cholinergic agonists on the biosynthesis and release of PLs from human fibroblast-like synoviocytes (FLS). Osteoarthritic human knee FLS were treated...
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Total fatty acid analysis is a routine method in many areas, including lipotyping of individuals in personalized medicine, analysis of foodstuffs, and optimization of oil production in biotechnology. This analysis is commonly done by converting fatty acyl (FA) chains of intact lipids into FA methyl esters (FAMEs) and monitoring these by gas-chromat...
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Background: As the gut microbiota contributes to metabolic health, it is important to determine specific diet-microbiota interactions that influence host metabolism. Bile acids and dietary fat source can alter phenotypes of diet-induced obesity, but the interplay with intestinal microorganisms is unclear. Here, we investigated metabolic consequenc...
Article
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Interactions between the gut microbial ecosystem and host lipid homeostasis are highly relevant to host physiology and metabolic diseases. We present a comprehensive multi-omics view of the effect of intestinal microbial colonization on hepatic lipid metabolism, integrating transcriptomic, proteomic, phosphoproteomic, and lipidomic analyses of live...
Article
Fatty acid transport protein4 (FATP4) is upregulated in acquired and central obesity and its polymorphisms are associated with blood lipids and insulin resistance. Patients with FATP4 mutations and mice with global FATP4 deletion exhibit skin abnormalities characterized as ischthyosis prematurity syndrome (IPS). Cumulating data have shown that an a...
Article
Cholestasis represents pathophysiologic syndromes defined as an impaired bile flow from the liver. As an outcome, bile acids accumulate and promote hepatocytes injury followed by liver cirrhosis and liver failure. Bile acids induce apoptosis, ER stress and mitochondrial membrane instability. In this study we aimed to investigate the role of cytosol...
Article
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Background Plasmalogens are either phosphatidylcholine (PC P) or phosphatidylethanolamine (PE P) glycerophospholipids containing a vinyl ether moiety in sn-1-position and an esterified fatty acid in sn-2 position. Multiple functions have been proposed, including reservoir of precursors for inflammatory mediators, modulation of membrane fluidity, an...
Data
Modulation of gene expression in lipoprotein treated macrophages. Hypergeometrical scores were calculated for each lipoprotein treatment versus untreated control cells as well as for HDL3 deloaded cells in comparison to loaded controls. A hypergeometrical score of >6 can been regarded as statistically significant. (XLSX)
Data
PANTHER overrepresentation test results, annotated with Reactome pathways. Regulated transcripts with a hypergeometrical score (HG) of more than six were analyzed for overrepresentation in Reactome pathways using the PANTHER engine. Resulting p-values were corrected for multiple testing. Pathways are listed in tables separated by lipoprotein (eLDL...
Article
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Species of the genus Wolffia are traditionally used as human food in some of the Asian countries. Therefore, all 11 species of this genus, identified by molecular barcoding, were investigated for ingredients relevant to human nutrition. The total protein content varied between 20 and 30% of the freeze-dry weight, the starch content between 10 and 2...
Article
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Lipids play very important roles in lung biology, mainly reducing the alveolar surface tension at the air-liquid interface thereby preventing end-expiratory collapse of the alveoli. In the present study we performed an extensive quantitative lipidomic analysis of mouse lung to provide the i) total lipid quantity, ii) distribution pattern of the maj...
Data
Molar ratios of lipid classes. Displayed are the values of molar ratios of lipid classes. Values are represented as mean ± SD. (DOC)
Data
Total lipid composition of mouse lung during postnatal development. The displayed values are mol% of the respective lipid class of all analyzed lipids. Panel A) Glycerophospholipids (GP), sphingolipids (SP), cholesteryl esters (CE) and cholesterol. Panel B) only GP, SP without CE and cholesterol. Values are represented as mean ± SD, p-value summary...
Data
Lipid profiling of mouse lung during postnatal development used in this study. The list of identified and quantified lipid molecules, experimental protocol, abbreviations and statistics. (XLS)
Data
Quantitative analyses of individual lipid classes in mouse lung during postnatal development. Values are expressed as nmol/mg wet weight and represented as mean ± SD. (DOC)
Data
Distribution of glycerophospholipids according to carbon chain length (total number of carbon atoms) and alkenyl chain (PE P) during postnatal development of mouse lung. Values are represented as nmol/mg wet weight. (DOC)
Data
Distribution of glycerophospholipids according to degree of unsaturation (total number of double bonds) during postnatal development of mouse lung. Saturated (total number of double bonds = 0), Monounsaturated (total number of double bonds = 1), Polyunsaturated (total number of double bonds ≥2) lipids. (TIF)
Article
Full-text available
Human blood is a self-regenerating, lipid-rich biologic fluid that is routinely collected in hospital settings. The inventory of lipid molecules found in blood plasma (plasma lipidome) offers insights into individual metabolism and physiology in health and disease. Disturbances in lipid metabolism also occur in conditions that are not directly link...
Article
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Sphingolipids are bioactive molecules associated with oxidative stress, inflammation, and neurodegenerative diseases, but poorly studied in the context of age-related macular degeneration (AMD), a prevalent sight-threatening disease of the ageing retina. Here, we found higher serum levels of hexosylceramide (HexCer) d18:1/16:0 in patients with chor...
Data
Selected SNPs for the sensitivity analysis with reference papers. (DOC)
Data
Corroboration of malondialdehyde-acetaldehyde protein adducts synthesis. (A) Native PAGE of bovine serum albumin (BSA), BSA treated with 1.33 or 20 mM malondialdehyde (MDA-BSA), and BSA modified with 20 mM MDA and 20 mM acetaldehyde (MAA-BSA) stained with Coomassie Blue. (B) Fluorescence intensity of 10 μg of unmodified BSA, MDA-BSA and MAA-BSA pro...
Data
Influence of acetylated-BSA (acetyl-BSA) in gene expression of WERI-Rb1 cells. (A) Native PAGE of bovine serum albumin (BSA) and BSA treated with 2 μL of acetic anhydride per mg of protein to produce acetyl-BSA. The gel was stained with Coomassie Blue. The table shows the retention factor relative to BSA (RfBSA) calculated as the ratio of the dista...
Data
Expression of selected genes in the ceramide metabolism in WERI-Rb1 cells. Expression of 15 genes from the ceramide metabolism evaluated by RT-PCR in retinoblastoma cell line WERI-Rb1. CERS3 presented a very low expression and was not included in later experiments. Ctrl lanes for each gene represent a control without cDNA addition. The lower molecu...
Data
Linear regression association of serum sphingolipid species to late age-related macular degeneration (AMD) stages. (DOC)
Data
Sequence of primers used for PCR analysis. (DOC)