Publications by authors named "Dirk Raddatz"

25 Publications

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The DIVE/DPV registries: evolution of empagliflozin use in clinical practice in Germany.

BMJ Open Diabetes Res Care 2020 07;8(1)

Freiburg University Hospital, Freiburg, Germany.

Introduction: Empagliflozin reduced morbidity and mortality in patients with type 2 diabetes mellitus (T2DM) in clinical trials. A registry study was undertaken to describe evolution of patient characteristics and assess the real-world effectiveness/safety of empagliflozin.

Research Design And Methods: Data from the Diabetes Patienten Verlaufsdokumentation (DPV)/Diabetes Versorgungsevaluation (DIVE) registries on 9571 adults with T2DM (registered in 2014-2019) receiving empagliflozin were used. Patients were grouped according to the following: early users (group 1; n=505) received empagliflozin before the EMPA-REG OUTCOME study publication (mid-September 2015); intermediate users (group 2; n=2961) started empagliflozin after the EMPA-REG OUTCOME publication but before the European Medicines Agency label change (from mid-September 2015 to mid-January 2017); and late users (group 3; n=6105) started empagliflozin after mid-January 2017. Data on clinical and treatment characteristics were collected.

Results: Over time, the proportion of recipients aged <65 years decreased (71.1% vs 54.4% among early and late adopters), male patients increased (from 50.9% to 66.5%), body mass index (mean±SD) decreased (from 35.5±6.7 to 32.7±6.6 kg/m), proportion with cardiovascular morbidities increased (from 20.4% to 26.4%), and mean estimated glomerular filtration rate decreased (from 83.2±19.5 to 78.5±21.1 mL/min/1.73 m) (all p<0.001). Patients increasingly received empagliflozin in combination with metformin (60.8% vs 68.6% of early and late adopters; p<0.001), glucagon-like peptide-1 (GLP-1) agonists (11.0 vs 14.1%; p<0.001) or insulin (34.3% vs 49.9%; p<0.001). Empagliflozin was generally added to existing antidiabetic regimens. Six months after empagliflozin initiation, the mean glycated hemoglobin (HbA1c) decreased by 0.4%, the proportion of patients with HbA1c <6.5% increased (19.2% vs 12.8%), and the mean fasting plasma glucose decreased (155.8±49.7 vs 168.0±55.1 mg/dL) (all p<0.001). No significant changes in rates of severe hypoglycemia and no cases of diabetic ketoacidosis were seen.

Conclusions: Over time, empagliflozin is being prescribed to a broader patient range in routine practice, is usually added to existing antidiabetic regimens, and is increasingly used in combination with metformin, GLP-1 agonists and/or insulin. Empagliflozin had a beneficial effect on glycemic control, with no increase in hypoglycemia.
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http://dx.doi.org/10.1136/bmjdrc-2020-001486DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7388887PMC
July 2020

Endoscopic intragastric balloon: a gimmick or a viable option for obesity?

Ann Transl Med 2020 Mar;8(Suppl 1):S8

Department of Gastroenterology and Gastrointestinal Oncology, Endocrine Unit, University Medical Center Göttingen, Göttingen, Germany.

Worldwide, the prevalence of obesity has doubled since 1980 in 70 countries. More than one in three adults now suffer from overweight or obesity. Health problems related to obesity include orthopedic problems, psychiatric conditions, metabolic and cardiovascular diseases, and of increasing concern, cancer. Thus, obesity has an enormous impact on the individual's wellbeing as well as on society's workforce and health care expenses. Medical efforts are ongoing to find safe and effective treatment options for obesity and its metabolic implications. At present, available treatment options include lifestyle interventions, pharmacotherapy, endoscopic applications, and bariatric surgery. Within the range of endoscopic treatment options, the intragastric balloon is the most widely used device. The idea is simple: the gastric volume is reduced by a balloon that is in most cases implanted by an endoscopic procedure similar to a gastroscopy. During the past decades, different models have been developed, which we will briefly introduce in this review. We aim at reviewing the pathophysiology underlying the effect of endoscopic intragastric balloon on weight loss and metabolic changes. We will assess expected short-term and long-term benefits for the patient, and we will discuss common side effects as well as rare complications. We will compare endoscopic intragastric balloon to conservative treatment options with or without pharmacological support on the one hand and to the spectrum of bariatric surgery on the other hand. In most patients, obesity must be considered a chronic disease that requires a lifelong treatment concept. In view of current treatment options for obesity, we will discuss whether endoscopic intragastric balloon is a viable treatment option, and who may be the right patient to benefit from it.
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http://dx.doi.org/10.21037/atm.2019.09.67DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7154325PMC
March 2020

Urine E-cadherin: A Marker for Early Detection of Kidney Injury in Diabetic Patients.

J Clin Med 2020 Feb 27;9(3). Epub 2020 Feb 27.

Clinic for Nephrology and Rheumatology, University Medical Center Göttingen 1, 37075 Göttingen, Germany.

Diabetic nephropathy (DN) is the main reason for end-stage renal disease. Microalbuminuria as the non-invasive available diagnosis marker lacks specificity and gives high false positive rates. To identify and validate biomarkers for DN, we used in the present study urine samples from four patient groups: diabetes without nephropathy, diabetes with microalbuminuria, diabetes with macroalbuminuria and proteinuria without diabetes. For the longitudinal validation, we recruited 563 diabetic patients and collected 1363 urine samples with the clinical data during a follow-up of 6 years. Comparative urinary proteomics identified four proteins Apolipoprotein A-I (APOA1), Beta-2-microglobulin (B2M), E-cadherin (CDH1) and Lithostathine-1-alpha (REG1A), which differentiated with high statistical strength ( < 0.05) between DN patients and the other groups. Label-free mass spectrometric quantification of the candidates confirmed the discriminatory value of E-cadherin and Lithostathine-1-alpha ( < 0.05). Immunological validation highlighted E-cadherin as the only marker able to differentiate significantly between the different DN stages with an area under the curve (AUC) of 0.85 (95%-CI: [0.72, 0.97]). The analysis of the samples from the longitudinal study confirmed the prognostic value of E-cadherin, the critical increase in urinary E-cadherin level was measured 20 ± 12.5 months before the onset of microalbuminuria and correlated significantly ( < 0.05) with the glomerular filtration rate measured by estimated glomerular filtration rate (eGFR).
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http://dx.doi.org/10.3390/jcm9030639DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7141221PMC
February 2020

Noninvasive assessment of liver fibrosis in a real-world cohort of patients with known or suspected chronic liver disease using 2D-shear wave elastography.

Eur J Gastroenterol Hepatol 2020 12;32(12):1559-1565

Department of Gastroenterology and Gastrointestinal Oncology.

Objectives: We aimed to investigate the diagnostic accuracy of liver stiffness measurement (LSM) by 2D-shear wave elastography (2D-SWE, GE, Logiq E9) in patients with known or suspected chronic liver disease and to define cutoff values for the different stages of fibrosis.

Methods: First, we retrospectively enrolled 21 patients in a pilot study and validated the results in a prospective cohort of 70 patients between May 2017 and February 2019. In all patients, LSM and liver biopsy were performed. We analyzed the diagnostic accuracy of LSM for the different fibrosis stages and examined the impact of additional clinical parameters on LSM.

Results: The success rate of LSM was 88.6%. In the prospective cohort, optimal cutoff values for F ≥ 1, F ≥ 2, F ≥ 3 and F = 4 were 6.24, 7.86, 8.05 and 10.74 kPa [area under the receiver operating characteristic curve (AUROC) 0.831, 0.913, 0.996 and 0.954]. In both cohorts and in the subgroup of patients with nonalcoholic fatty liver disease (NAFLD) (n = 35), a cutoff value of 8.05 kPa differentiates patients with advanced fibrosis (F ≥ 3) and patients with no or mild fibrosis (F0-F2) with high diagnostic accuracy (AUROC 0.995-1.000). Parameters such as age, sex, BMI, bilirubin- and alanine aminotransferase-level had no significant impact on LSM.

Conclusion: LSM by 2D-SWE is an excellent method to differentiate between patients with advanced fibrosis (F ≥ 3) and patients with no or mild fibrosis (F ≤ 2). We were able to show this also in a subgroup of patients with NAFLD.
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http://dx.doi.org/10.1097/MEG.0000000000001675DOI Listing
December 2020

Favorable 90-Day Mortality in Obese Caucasian Patients with Septic Shock According to the Sepsis-3 Definition.

J Clin Med 2019 Dec 24;9(1). Epub 2019 Dec 24.

Department of Anesthesiology, University Medical Center, Georg August University, D-37075 Goettingen, Germany.

Septic shock is a frequent life-threatening condition and a leading cause of mortality in intensive care units (ICUs). Previous investigations have reported a potentially protective effect of obesity in septic shock patients. However, prior results have been inconsistent, focused on short-term in-hospital mortality and inadequately adjusted for confounders, and they have rarely applied the currently valid Sepsis-3 definition criteria for septic shock. This investigation examined the effect of obesity on 90-day mortality in patients with septic shock selected from a prospectively enrolled cohort of septic patients. A total of 352 patients who met the Sepsis-3 criteria for septic shock were enrolled in this study. Body-mass index (BMI) was used to divide the cohort into 24% obese (BMI ≥ 30 kg/m) and 76% non-obese (BMI < 30 kg/m) patients. Kaplan-Meier survival analysis revealed a significantly lower 90-day mortality (31% vs. 43%; = 0.0436) in obese patients compared to non-obese patients. Additional analyses of baseline characteristics, disease severity, and microbiological findings outlined further statistically significant differences among the groups. Multivariate Cox regression analysis estimated a significant protective effect of obesity on 90-day mortality after adjustment for confounders. An understanding of the underlying physiologic mechanisms may improve therapeutic strategies and patient prognosis.
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http://dx.doi.org/10.3390/jcm9010046DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7019854PMC
December 2019

Comparing clinical characteristics of pediatric patients with pancreatic diabetes to patients with type 1 diabetes: A matched case-control study.

Pediatr Diabetes 2019 11 23;20(7):955-963. Epub 2019 Jul 23.

Institute of Epidemiology and Medical Biometry, ZIBMT, University of Ulm, Ulm, Germany.

Background: Only few studies have been conducted on pancreatic diabetes and data from large epidemiological studies are missing. Our main objective was to study the most important differences and similarities between pediatric individuals with pancreatic diabetes and type 1 diabetes (T1D).

Methods: Patients <20 years of age were identified from the diabetes patient follow-up registry (DPV). Data of the most recent treatment year between January 2000 and March 2018 were aggregated. Propensity score was used to match individuals with pancreatic diabetes to individuals with T1D. Matching was conducted one-to-one by sex, age, diabetes duration, body mass index SD score (BMI-SDS), and migration background.

Results: We studied 731 individuals with pancreatic diabetes and 74 460 with T1D. In the matched cohort of 631 pairs, HbA1c was significantly lower in pancreatic diabetes (7.4% [95% confidence interval: 7.2; 7.5%]) compared to T1D patients (8.7% [8.5; 8.8%]). Daily insulin dose (0.80 IU/kg [0.77; 0.84] vs 0.86 IU/kg [0.82; 0.90]) and insulin pump use (13.3% [10.7; 16.4] vs 22.1% [19.0; 25.6%]) were lower in patients with pancreatic diabetes. However, event rates of severe hypoglycemia were similar between pancreatic and T1D patients (8.8 [5.4; 14.2] vs 9.6 [5.9; 15.6] events per 100 patient years).

Conclusions: With the use of robust epidemiological data, our study improves the knowledge on clinical characteristics in pediatric individuals with pancreatic diabetes. Moreover, our results serve as a basis to reconsider treatment options and for discussing clinical practice guidelines for patients with this rare medical condition.
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http://dx.doi.org/10.1111/pedi.12894DOI Listing
November 2019

Metabolic Endoscopy: Development and Perspectives.

Authors:
Dirk Raddatz

Digestion 2019 7;100(3):147-151. Epub 2019 Feb 7.

Department of Gastroenterology and Endocrinology, University Medical Center Goettingen, Goettingen, Germany,

Background: Obesity and its metabolic sequelae are among the most serious challenges faced by health systems today and they are expected to pose a serious threat in the future as well. Therapy ranges from lifestyle modification to drug treatment to surgery. Metabolic endoscopy (ME) might close the gap between invasive "metabolic" surgery and conservative, less effective treatment. In recent years, several endoscopic approaches have emerged, promising a safe and effective approach to cope with obesity. Data on metabolic endpoints is scarce. This article will therefore highlight procedures with data on type 2 diabetes mellitus (T2DM) as the most prominent component of the metabolic syndrome.

Summary: Most procedures showed beneficial effects in terms of weight reduction. For gastric procedures, there were no systematic studies primarily addressing parameters of glucose metabolism or diabetes outcomes. Metabolic benefit, if there is any, is most likely a by-product of weight loss. By contrast, duodenal-jejunal bypass sleeve (DJBS) is conceptually an antidiabetic procedure. Although adverse events are frequent, recent data points to a positive benefit-risk ratio. Key Messages: ME has the potential to constitute a growing field in the treatment of obesity and associated T2DM. While data published on glycaemic parameters in restrictive approaches is not sufficient, there is strong evidence that malabsorptive DJBS has an antidiabetic "plus" effect. Further studies are necessary to define the role of ME within a lifelong concept of treating obesity and T2DM.
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http://dx.doi.org/10.1159/000494428DOI Listing
February 2020

Regional differences in type 2 diabetes treatment and outcomes in Germany-An analysis of the German DPV and DIVE registries.

Diabetes Metab Res Rev 2018 11 19;34(8):e3049. Epub 2018 Sep 19.

Institute of Epidemiology and Medical Biometry, ZIBMT, University of Ulm, Ulm, Germany.

Aims: On the basis of the Diabetes Versorgungs-Evaluation (DIVE) and Diabetes-Patienten-Verlaufsdokumentation (DPV) datasets, we aimed to explore the impact of differences in treatment modalities on outcomes in Germany and put these into a global context.

Methods: The 2014 to 2016 DIVE and DPV databases were combined, and a total of 127 838 patients 18 years and older was analysed with respect to demographics, cardiovascular risk factors, comorbidities, treatments, and outcomes, separately for each German state. Estimates were expressed as adjusted least squares means together with 95% confidence intervals.

Results: Saarland dataset recorded the lowest mean HbA (6.7%; 6.6%-6.8%; 50 mmol/mol, 49-51 mmol/mol), Saxony-Anhalt showed the highest (8.3%; 8.2%-8.3%; 67 mmol/mol, 66-67 mmol/mol). The highest percentage of hypoglycaemic events was reported in Mecklenburg-West Pomerania (MWP) (4.7%; 3.9%-5.7%), the lowest in Thuringia (0.9%; 0.2%-3.4%). Metformin and sulfonylurea accounted for 36.4% to 53.3% of anti-diabetic treatments across states; other antihyperglycaemic drugs such as DPP-4 inhibitors, SGLT2 inhibitors, and GLP-1 analogues were used most often in MWP (40.0%; 37.8%-42.1%) and least in Rhineland-Palatinate (13.6%; 13.0%-14.2%). Treatment with insulin (alone or in combination) was reported most often in MWP (78.2%; 76.4%-80.0%) and least in Thuringia (26.0%; 20.1%-32.9%).

Conclusions: Federal states in Germany are heterogeneous concerning diabetes treatment and associated outcomes. These data should stimulate further discussion about how optimal diabetes care can be implemented in all areas of Germany, to achieve good treatment outcomes in all federal states.
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http://dx.doi.org/10.1002/dmrr.3049DOI Listing
November 2018

Lack of correlation between Treg quantification assays in inflammatory bowel disease patients.

World J Gastroenterol 2015 Mar;21(11):3325-9

Gunnar Brandhorst, Darinka Todorova Petrova, Sebastian Weigand, Christoph Eberle, Nicolas von Ahsen, Department of Clinical Chemistry, University Medical Center, 37075 Goettingen, Germany.

Aim: To compare the number of regulatory T-cells (Tregs) measured by flow cytometry with those obtained using a real-time quantitative PCR (qPCR) method in patients suffering from inflammatory bowel disease (IBD).

Methods: Tregs percentages obtained by both flow cytometry and qPCR methods in 35 adult IBD patients, 18 out of them with Crohn´s disease (CD) and 17 with ulcerative colitis (UC) were compared to each other as well as to scores on two IBD activity questionnaires using the Harvey Bradshaw Index (HBI) for CD patients and the Simple Colitis Clinical Activity Index (SCCAI) for UC patients. The Treg percentages by flow cytometry were defined as CD4(+)CD25(high)CD127(low)FOXP3(+) cells in peripheral blood mononuclear cells, whereas the Treg percentages by qPCR method were determined as FOXP3 promoter demethylation in genomic DNA.

Results: We found an average of 1.56% ± 0.78% Tregs by using flow cytometry, compared to 1.07% ± 0.53% Tregs by using qPCR in adult IBD patients. There were no significant correlations between either the percentages of Tregs measured by flow cytometry or qPCR and the HBI or SCCAI questionnaire scores in CD or UC patients, respectively. In addition, there was no correlation between Treg percentages measured by qPCR and those measured by flow cytometry (r = -0.06, P = 0.73; Spearman Rho). These data suggest that, either Treg-related immune function or the clinical scores in these IBD patients did not accurately reflect actual disease activity. Until the cause(s) for these differences are more clearly defined, the results suggest caution in interpreting studies of Tregs in various inflammatory disorders.

Conclusion: The two methods did not produce equivalent measures of the percentage of total Tregs in the IBD patients studied which is consistent with the conclusion that Tregs subtypes are not equally detected by these two assays.
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http://dx.doi.org/10.3748/wjg.v21.i11.3325DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4363763PMC
March 2015

Prednisolone and azathioprine are effective in DPPX antibody-positive autoimmune encephalitis.

Neurol Neuroimmunol Neuroinflamm 2015 Jun 12;2(3):e86. Epub 2015 Mar 12.

Clinic for Neurology (K.S., P.-O.C., J.S.), Division of Gastroenterology and Endocrinology (D.R.), Department of Internal Medicine, and Department of Neuroimmunology (J.S.), Institute for Multiple Sclerosis Research and Hertie Foundation, University Medical Center Göttingen, Germany; Molecular Neuroimmunology (S.J., B.W.), Department of Neurology, University of Heidelberg, Germany; and Institute of Experimental Immunology (W.S.), Euroimmun AG, Lübeck, Germany.

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http://dx.doi.org/10.1212/NXI.0000000000000086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4360797PMC
June 2015

Combination of alcohol and fructose exacerbates metabolic imbalance in terms of hepatic damage, dyslipidemia, and insulin resistance in rats.

PLoS One 2014 7;9(8):e104220. Epub 2014 Aug 7.

Department Gastroenterology and Endocrinology, University Medical Center Goettingen, Goettingen, Germany.

Although both alcohol and fructose are particularly steatogenic, their long-term effect in the development of a metabolic syndrome has not been studied in vivo. Consumption of fructose generally leads to obesity, whereas ethanol can induce liver damage in the absence of overweight. Here, Sprague-Dawley rats were fed ad libitum for 28 days on five diets: chow (control), liquid Lieber-DeCarli (LDC) diet, LDC +30%J of ethanol (L-Et) or fructose (L-Fr), and LDC combined with 30%J ethanol and 30%J fructose (L-EF). Body weight (BW) and liver weight (LW) were measured. Blood and liver samples were harvested and subjected to biochemical tests, histopathological examinations, and RT-PCR. Alcohol-containing diets substantially reduced the food intake and BW (≤3rd week), whereas fructose-fed animals had higher LW than controls (P<0.05). Additionally, leukocytes, plasma AST and leptin levels were the highest in the fructose-administered rats. Compared to the chow and LDC diets, the L-EF diet significantly elevated blood glucose, insulin, and total-cholesterol levels (also vs. the L-Et group). The albumin and Quick-test levels were the lowest, whereas ALT activity was the highest in the L-EF group. Moreover, the L-EF diet aggravated plasma triglyceride and reduced HDL-cholesterol levels more than 2.7-fold compared to the sum of the effects of the L-Et and L-Fr diets. The decreased hepatic insulin clearance in the L-EF group vs. control and LDC groups was reflected by a significantly decreased C-peptide:insulin ratio. All diets except the control caused hepatosteatosis, as evidenced by Nile red and H&E staining. Hepatic transcription of insulin receptor substrate-1/2 was mainly suppressed by the L-Fr and L-EF diets. The L-EF diet did not enhance the mitochondrial β-oxidation of fatty acids (Cpt1α and Ppar-α expressions) compared to the L-Et or L-Fr diet. Together, our data provide evidence for the coaction of ethanol and fructose with a high-fat-diet on dyslipidemia and insulin resistance-accompanied liver damage.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0104220PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4125190PMC
November 2015

Melanocortin receptors in rat liver cells: change of gene expression and intracellular localization during acute-phase response.

Histochem Cell Biol 2012 Mar 20;137(3):279-91. Epub 2011 Dec 20.

Division of Gastroenterology and Endocrinology, Department of Internal Medicine, University Medical Center Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany.

MCRs are known to be expressed predominantly in the brain where they mediate metabolic and anti-inflammatory functions. Leptin plays an important role in appetite and energy regulation via signaling through melanocortin receptors (MCRs) in the brain. As serum levels of MCR ligands are elevated in a clinical situation [acute-phase response (APR)] to tissue damage, where the liver is responsible for the metabolic changes, we studied hepatic gene expression of MCRs in a model of muscle tissue damage induced by turpentine oil (TO) injection in rats. A significant increase in gene expression of all five MCRs (MC4R was the highest) in liver at the RNA and protein level was detected after TO injection. A similar pattern of increase was also found in the brain. Immunohistology showed MC4R in the cytoplasm, but also in the nucleus of parenchymal and non-parenchymal liver cells, whereas MC3R-positivity was mainly cytoplasmic. A time-dependent migration of MC4R protein from the cytoplasm into the nucleus was observed during APR, in parallel with an increase in α-MSH and leptin serum levels. An increase of MC4R was detected at the protein level in wild-type mice, while such an increase was not observed in IL-6ko mice during APR. Moreover, treatment of isolated liver cells with melanocortin agonists (α-MSH and THIQ) inhibited the endotoxin-induced upregulation of the acute-phase cytokine (IL-6, IL1β and TNF-α) gene expression in Kupffer cells and of chemokine gene expression in hepatocytes. MCRs are expressed not only in the brain, but also in liver cells and their gene expression in liver and brain tissue is upregulated during APR. Due to the presence of specific ligands in the serum, they may mediate metabolic changes and exert a protective effect on liver cells.
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http://dx.doi.org/10.1007/s00418-011-0899-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3312751PMC
March 2012

A TNF-regulated recombinatorial macrophage immune receptor implicated in granuloma formation in tuberculosis.

PLoS Pathog 2011 Nov 17;7(11):e1002375. Epub 2011 Nov 17.

Department of Surgery, University of Göttingen, Göttingen, Germany.

Macrophages play a central role in host defense against mycobacterial infection and anti- TNF therapy is associated with granuloma disorganization and reactivation of tuberculosis in humans. Here, we provide evidence for the presence of a T cell receptor (TCR) αβ based recombinatorial immune receptor in subpopulations of human and mouse monocytes and macrophages. In vitro, we find that the macrophage-TCRαβ induces the release of CCL2 and modulates phagocytosis. TNF blockade suppresses macrophage-TCRαβ expression. Infection of macrophages from healthy individuals with mycobacteria triggers formation of clusters that express restricted TCR Vβ repertoires. In vivo, TCRαβ bearing macrophages abundantly accumulate at the inner host-pathogen contact zone of caseous granulomas from patients with lung tuberculosis. In chimeric mouse models, deletion of the variable macrophage-TCRαβ or TNF is associated with structurally compromised granulomas of pulmonary tuberculosis even in the presence of intact T cells. These results uncover a TNF-regulated recombinatorial immune receptor in monocytes/macrophages and demonstrate its implication in granuloma formation in tuberculosis.
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http://dx.doi.org/10.1371/journal.ppat.1002375DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3219713PMC
November 2011

The anti-TNF-α antibody infliximab indirectly regulates PECAM-1 gene expression in two models of in vitro blood cell activation.

Lab Invest 2012 Feb 31;92(2):166-77. Epub 2011 Oct 31.

Department of Internal Medicine, Division of Gastroenterology and Endocrinology, University Hospital, Georg-August University Göttingen, Göttingen, Germany.

Chronic inflammatory bowel diseases can be successfully treated with antibodies against the acute phase mediator TNF-α. The process of activation and of extravasation of inflammatory cells from the blood into the 'stressed' tissue site is controlled by cytokines and chemokines, which attract leukocytes and by adhesion molecules, which mediate their attachment and transmigration toward the affected cell(s). The changes in the gene expression of adhesion molecules taking place in those cells before attachment have been less investigated. Changes of PECAM-1, ICAM-1 and vascular cell adhesion molecule-1 (VCAM-1) gene expression were studied in phytohaemagglutinin (PHA)- and lipolysaccharide (LPS)-treated human peripheral blood leukocytes (PBLs), granulocytes and the human monocyte cell line U-937. Cells were treated either with PHA or with LPS in the presence or absence of infliximab and incubated with TNF-α, IFN-γ and/or transforming growth factor beta (TGF-β) and treated as above. Activation of PBLs by PHA or LPS treatment triggered a sharp upregulation of ICAM-1, VCAM-1 gene expression and a time-dependent downregulation of PECAM-1 gene expression reaching a minimum 4 h from start of the experiment. The anti-TNF-α antibody infliximab, by neutralizing TNF-α and IFN-γ production, completely reversed PECAM-1 mRNA downregulation and ICAM-1 and VCAM-1 upregulation. Immunostaining of PBLs cytospins with antibodies against PECAM-1 and ICAM-1 confirmed RT-PCR and western blot results. PBLs IFN-γ or TNF-α treatment downregulated PECAM-1 in parallel with the upregulation of ICAM-1 and VCAM-1 gene expression, whereas TGF-β upregulated PECAM-1- and downregulated ICAM-1 and VCAM-1 gene expression counteracting the effect of TNF-α or IFN-γ. Similar results were obtained in human U937 cells and in granulocyte cultures by TNF-α or IFN-γ treatment. Taken together, these results suggest that infliximab, blocking TNF-α and IFN-γ production, exerts its anti-inflammatory effect through inhibiting downregulation of PECAM-1 gene expression and upregulation of ICAM-1 and VCAM-1 expression in leukocytes of the peripheral blood. These results also suggest that TGF-β may thus be of therapeutic importance as an anti-inflammatory agent.
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http://dx.doi.org/10.1038/labinvest.2011.160DOI Listing
February 2012

Preserved Na(+)/H(+) exchanger isoform 3 expression and localization, but decreased NHE3 function indicate regulatory sodium transport defect in ulcerative colitis.

Inflamm Bowel Dis 2010 Jul;16(7):1149-61

Department of Gastroenterology, Hannover Medical School, Hannover, Germany.

Background: A major causative factor of diarrhea in ulcerative colitis (UC) patients is the loss of Na(+) absorptive capacity of the inflamed colonic mucosa. Potential contributing mechanisms include reduced driving force for active transport, and impaired expression, mislocalization, or defective transport function of Na(+) absorptive proteins. We therefore studied the expression, brush border membrane (BBM) localization, and transport capacity of the major intestinal Na(+) absorptive protein, the Na(+)/H(+) exchanger isoform 3 (NHE3) in biopsies from UC patients.

Methods: In UC and control biopsies, inflammation was graded histologically, NHE3, tumor necrosis factor alpha (TNF-alpha), villin, as well as other housekeeping genes were analyzed by quantitative real-time polymerase chain reaction (PCR), BBM localization of NHE3 determined by immunohistochemistry, and confocal microscopy. Na(+) absorptive capacity was assessed by (22)Na(+) isotope fluxes and NHE3 transport activity measured microfluorometrically in BCECF-loaded surface colonocytes within isolated crypts.

Results: In mildly, moderately, and severely inflamed sigmoid colon of UC patients, neither NHE3 mRNA expression nor the abundance of NHE3 in the BBM was significantly altered compared to other structural components of the BBM. However, Na(+) absorption was strongly reduced by approximately 80% and acid-activated NHE3 transport activity was significantly decreased in the surface cells of sigmoid colonic crypts even in moderately inflamed mucosa.

Conclusions: In the colonic mucosa of patients with active UC, NHE3 transport capacity was found significantly decreased despite correct NHE3 location and abundance in the brush border, independent of current treatment. These findings suggest functional NHE3 transport as a novel factor for inflammatory diarrhea in UC patients.
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http://dx.doi.org/10.1002/ibd.21183DOI Listing
July 2010

Effect of radiation on gene expression of rat liver chemokines: in vivo and in vitro studies.

Radiat Res 2008 Feb;169(2):162-9

Department of Gastroenterology and Endocrinology, Gottingen University, 37075 Goettingen, Germany.

The aim of the study was to analyze the effect of a single irradiation on chemokine gene expression in the rat liver and in isolated rat hepatocytes. RNA extracted from livers and from hepatocytes within the first 48 h after irradiation was analyzed by real-time PCR and the Northern blot assay. The chemokine concentrations in the serum of irradiated rats were measured quantitatively by ELISA. A significant radiation-induced increase of CINC1, IP10, MCP1, MIP3alpha, MIP3beta, MIG and ITAC gene expression could be detected at the RNA level in the liver. CINC1, MCP1 and IP10 serum levels were significantly increased. In rat hepatocytes in vitro, only MIP3alpha showed a radiation-induced increase in expression, while CINC1, IP10, MIP3beta, MIG, MIP1alpha, ITAC and SDF1 RNA levels were significantly down-regulated. However, incubation of irradiated hepatocytes in vitro with either TNF-alpha, IL1beta, or IL6 plus TNF-alpha led to up-regulation of MCP1, IP10 and MCP1 or CINC1 and MIP3beta, respectively. Irradiation of the liver induces up-regulation of the genes of the main proinflammatory chemokines, probably through the action of locally synthesized proinflammatory cytokines. The reason for the lack of liver inflammation in this model has still to be clarified.
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http://dx.doi.org/10.1667/RR1006.1DOI Listing
February 2008

NF-kappaB-dependent synergistic regulation of CXCL10 gene expression by IL-1beta and IFN-gamma in human intestinal epithelial cell lines.

Int J Colorectal Dis 2008 Mar 28;23(3):305-17. Epub 2007 Nov 28.

Centre for Internal Medicine, Department of Gastroenterology and Endocrinology, University of Göttingen, Goettingen, Germany.

Background And Aims: Little is known about the intestinal epithelial expression and secretion of CXCL10 (IP-10), a chemokine involved in recruiting T cells and monocytes. We aimed to study CXCL10 gene expression and regulation by the pro-inflammatory cytokines interleukin (IL)-1beta, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha in intestinal epithelial cell lines.

Materials And Methods: CXCL10 expression and secretion kinetics were assessed in Caco-2, HT-29 and DLD1 human colon epithelial cells, treated with IL-1beta, TNF-alpha, IFN-gamma alone or in combination with each other by real-time polymerase chain reaction (PCR), Northern blotting and enzyme-linked immunoabsorbent assay (ELISA). Transient transfections with TGL-IP10 (CXCL10 promoter) and TGL-IP10-kappaB2 mutant promoter and gelshifts and supershifts for nuclear factor (NF)-kappaB were also performed.

Results: Real-time PCRs and ELISA experiments revealed that IL-1beta was the strongest and earliest inducer of CXCL10 messenger ribonucleic acid (mRNA) expression and protein secretion in Caco-2 cell line, whereas INF-gamma had a delayed kinetics. There was a strong synergistic effect of either TNF-alpha or IL-1beta with IFN-gamma both on CXCL10 mRNA expression and protein secretion in all three cell lines. Real-time PCR and ELISA experiments using a specific NF-kappaB inhibitor and transfection experiments with a NF-kappaB-binding defective CXCL10 promoter construct revealed that the induction of CXCL10 by IL-1beta and its synergism with IFN-gamma is NF-kappaB dependent.

Conclusion: These data demonstrate that in colonic epithelial cells, depending on the cellular context and utilizing the NF-kappaB pathway, IL-1beta alone and/or in synergism with IFN-gamma may play a major role in the induction of CXCL10.
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http://dx.doi.org/10.1007/s00384-007-0396-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2225996PMC
March 2008

Quantitative gene expression of cytokines in peripheral blood leukocytes stimulated in vitro: modulation by the anti-tumor nerosis factor-alpha antibody infliximab and comparison with the mucosal cytokine expression in patients with ulcerative colitis.

Transl Res 2007 Oct 11;150(4):223-32. Epub 2007 May 11.

Department of Internal Medicine, Section of Gastroenterology and Endocrinology, Georg-August University, Göttingen, Germany.

Emerging data indicate that alterations in cytokine synthesis play a role in inflammatory bowel disease (IBD) pathogenesis. In this study, we quantified mRNA expression of the main acute-phase cytokines and T-cell cytokines in biopsies from patients with established ulcerative colitis (UC) and compared it with that obtained in biopsies from normal controls. Quantification of cytokine gene expression was also evaluated in in vitro phytohemagglutinin (PHA)-treated peripheral blood leukocytes (PBLs) at the RNA and protein levels. The in vitro influence of the anti-tumor necrosis factor-alpha (TNF-alpha) antibody infliximab (INFL) on PHA-treated PBLs was also evaluated. Analyzing inflamed specimens from UC patients compared with control samples, interleukin (IL)-6 was sharply the most induced cytokine. Interestingly, similar results were found in activated PBLs, where acute-phase cytokines were more abundantly expressed compared with T-cell cytokines. IL-6 was confirmed to be the most induced with a maximum increase of 1110-fold after 4 h of PHA stimulation, followed by TNF-alpha and IL-1beta as well as interferon-gamma (IFN-gamma). Surprisingly, analyzing cytokine-mRNA expression from activated PBLs, the time kinetics and quantity of IFN-gamma was more similar to that of the acute-phase proteins than to that of the T-cell cytokines, which were upregulated after 1 h. The upregulation of cytokine-mRNA was translated into protein as demonstrated by enzyme-linked immunosorbent assay. IFN-gamma was also strongly expressed in the RNA from UC biopsies. TNF-alpha protein was not detectable at all in INFL-treated cultures. INFL did not induce a reduction of TNF-alpha-mRNA nor of IL-1beta-mRNA, but it reduced IFN-gamma- mRNA and, to a lesser extent, IL-6-mRNA; it also reduced the T-cell-derived cytokine IL-2. The in vitro model of PHA-stimulated PBLs may mimic inflammation processes observed in vivo. INFL may reduce inflammation in vivo through inhibition of both monocyte and T-cell activation.
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http://dx.doi.org/10.1016/j.trsl.2007.04.004DOI Listing
October 2007

Negative inotropy of the gastric proton pump inhibitor pantoprazole in myocardium from humans and rabbits: evaluation of mechanisms.

Circulation 2007 Jul 18;116(1):57-66. Epub 2007 Jun 18.

Herzzentrum, Kardiologie und Pneumologie, Georg-August Universitaet Goettingen, Robert-Koch Strasse 40, 37099 Goettingen, Germany.

Background: Proton pump inhibitors are used extensively for acid-related gastrointestinal diseases. Their effect on cardiac contractility has not been assessed directly.

Methods And Results: Under physiological conditions (37 degrees C, pH 7.35, 1.25 mmol/L Ca2+), there was a dose-dependent decrease in contractile force in ventricular trabeculae isolated from end-stage failing human hearts superfused with pantoprazole. The concentration leading to 50% maximal response was 17.3+/-1.3 microg/mL. Similar observations were made in trabeculae from human atria, normal rabbit ventricles, and isolated rabbit ventricular myocytes. Real-time polymerase chain reaction demonstrated the expression of gastric H+/K+-adenosine triphosphatase in human and rabbit myocardium. However, measurements with BCECF-loaded rabbit trabeculae did not reveal any significant pantoprazole-dependent changes of pH(i). Ca2+ transients recorded from field-stimulated fluo 3-loaded myocytes (F/F0) were significantly depressed by 10.4+/-2.1% at 40 microg/mL. Intracellular Ca2+ fluxes were assessed in fura 2-loaded, voltage-clamped rabbit ventricular myocytes. Pantoprazole (40 microg/mL) caused an increase in diastolic [Ca2+]i by 33+/-12%, but peak systolic [Ca2+]i was unchanged, resulting in a decreased Ca2+ transient amplitude by 25+/-8%. The amplitude of the L-type Ca2+ current (I(Ca,L)) was reduced by 35+/-5%, and sarcoplasmic reticulum Ca2+ content was reduced by 18+/-6%. Measurements of oxalate-supported sarcoplasmic reticulum Ca2+ uptake in permeabilized cardiomyocytes indicated that pantoprazole decreased Ca2+ sensitivity (Kd) of sarcoplasmic reticulum Ca2+ adenosine triphosphatase: control, Kd=358+/-15 nmol/L; 40 microg/mL pantoprazole, Kd=395+/-12 nmol/L (P<0.05). Pantoprazole also acted on cardiac myofilaments to reduced Ca2+-activated force.

Conclusions: Pantoprazole depresses cardiac contractility in vitro by depression of Ca2+ signaling and myofilament activity. In view of the extensive use of this agent, the effects should be evaluated in vivo.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.106.666008DOI Listing
July 2007

Isopropanolic extract of black cohosh stimulates osteoprotegerin production by human osteoblasts.

J Bone Miner Res 2005 Nov 18;20(11):2036-43. Epub 2005 Jul 18.

Department of Obstetrics and Gynecology, Georg-August-University of Göttingen, Göttingen, Germany.

Unlabelled: An isopropanolic extract (iCR) from the rhizomes of Cimicifuga racemosa (black cohosh) is used an alternative in the treatment of menopausal symptoms, and animal studies suggest positive skeletal effects. iCR stimulated osteoblastic OPG protein secretion by 3- to 5-fold as early as 12 h without affecting RANKL expression. The iCR effect, abrogated by the pure estrogen receptor antagonist ICI 182,780, also enhanced ALP activity (4-fold) and osteocalcin expression (3-fold), possibly contributing to the skeletal effects of black cohosh.

Introduction: Despite its positive effects on the skeleton, estrogen replacement therapy is no longer recommended as first-line therapy for the prevention and treatment of postmenopausal osteoporosis because it increases cardiovascular, thromboembolic, and breast cancer risk. Recently, herbal therapeutics such as an isopropanolic extract (iCR) from the rhizomes of Cimicifuga (=Actaea) racemosa (black cohosh) are gaining interest as an alternative in the treatment of menopausal symptoms. Whereas animal studies in rats suggest positive skeletal effects, the mechanism of its actions on bone cells remain unclear. RANKL is essential for osteoclast formation and activation, while osteoprotegerin (OPG) neutralizes RANKL.

Materials And Methods: In this study, we assessed the effects of iCR on OPG and RANKL mRNA steady-state levels by semiquantitative RT-PCR and on protein production by an ELISA system in human osteoblasts (hOBs).

Results: Under serum-free conditions, treatment with iCR increased OPG mRNA levels and protein secretion of hOBs by 2- to 3-fold in a dose-dependent manner, with a maximum effect at a 10(6)-fold dilution of iCR (p < 0.001) after 24-48 h. Time-course experiments indicated a stimulatory effect of iCR on osteoblastic OPG protein secretion by 3- to 5-fold (p < 0.001) as early as 12 h, whereas RANKL expression was very low and was not found to be modulated by iCR. Of note, the stimulatory effect of iCR on OPG production was abrogated by the pure estrogen receptor antagonist ICI 182,780. Moreover, iCR enhanced two osteoblastic differentiation markers, bone-specific alkaline phosphatase activity and osteocalcin expression, by up to 4- and 3-fold, respectively (p < 0.001).

Conclusions: Our data suggest that iCR enhances differentiation and increases the OPG-to-RANKL ratio of normal human osteoblasts. These effects may contribute to the positive skeletal effects of black cohosh.
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http://dx.doi.org/10.1359/JBMR.050716DOI Listing
November 2005

Quantitative measurement of cytokine mRNA in inflammatory bowel disease: relation to clinical and endoscopic activity and outcome.

Eur J Gastroenterol Hepatol 2005 May;17(5):547-57

Medical Clinic, Department of Gastroenterology and Endocrinology, Georg-August University, Göttingen, Germany.

Objective: The objective of this study was to quantitatively determine cytokine mRNA expression in inflammatory bowel disease under different clinical conditions including active disease, remission or an impaired response to a glucocorticoid (GC) therapy.

Methods: Mucosal biopsies were taken from 33 patients with ulcerative colitis (UC), 21 patients with Crohn's disease (CD) and 11 controls. Peripheral blood mononuclear cells (PBMNC) were isolated from 24 CU patients, 18 CD patients and 11 controls. Cytokine-mRNA [interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-10, interferon gamma (IFN-gamma), tumour necrosis factor alpha (TNF-alpha)] expression was measured by quantitative reverse transcriptase-polymerase chain reaction in biopsies and PBMNC, and correlated to endoscopic findings, clinical activity and outcome after 6 months GC therapy.

Results: IL-1beta, IL-6 and TNF-alpha were the largely dominating cytokines. In contrast to IL-1beta and TNF-alpha-, IL-6 expression was restricted to inflamed mucosa and correlated with the clinical activity and C-reactive protein levels in cases of pancolitis ulcerosa. TNF-alpha was elevated in CD even in endoscopic normal tissue. IL-2 and IFN-gamma were downregulated in PBMNC from CD and UC. No Th1 or Th2 specificity could be detected. Cytokine mRNA levels did not correlate with the response to a GC therapy.

Conclusion: IL-6 sharply distinguishes between inflamed and non-inflamed mucosa, and is therefore a suitable marker of intestinal inflammation. Its selective expression in the inflammatory site makes it an interesting target for future therapeutic strategies. TNF-alpha overexpression even in remission suggests a key role of this cytokine in CD pathogenesis and is possibly a feature that allows one to differentiate CD from UC.
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http://dx.doi.org/10.1097/00042737-200505000-00012DOI Listing
May 2005

Quality of life and outcome of ultrasound-guided laser interstitial thermo-therapy for non-resectable liver metastases of colorectal cancer.

Eur J Gastroenterol Hepatol 2004 Apr;16(4):389-95

Abteilung für Gastroenterologie und Endokrinologie, Zentrum Innere Medizin, Georg-August-Universität, Göttingen, Germany.

Objective: Patients with non-resectable liver metastases of colorectal cancer have poor prognosis and are mainly treated by palliative chemotherapy. Laser interstitial thermo-therapy is an innovative minimal invasive procedure for local tumour destruction within solid organs. The aim of the study was to investigate quality of life and outcome of ultrasound-guided laser interstitial thermo-therapy (US-LITT) in patients with liver metastases of colorectal cancer.

Methods: In this prospective non-randomized study, 45 patients with liver metastases of colorectal cancer were palliatively treated by US-LITT. Patient survival was analysed by the Kaplan-Meier method and the quality of life by questionnaire C30 of the European Organisation for Research and Treatment of Cancer before, and 1 week, 1 month, and 6 months after initiation of US-LITT.

Results: Median survival after initiation of US-LITT was 8.5 +/- 0.7 months with a range of 1.5-18 months. Body weight was constant 1 month after US-LITT. In the multivariate analyses, quality-of-life symptoms and functioning scales did not deteriorate in patients alive at 6 months after initiation of US-LITT. Univariate analyses outlined a significant increase of the pain subscale before and at 1 week after US-LITT.

Conclusions: This study first describes the quality of life in patients with liver metastases of colorectal cancer treated by US-LITT. Potential benefits of the minimal invasive procedure could be prolonged survival time by preserved quality of life, but this first impression needs to be verified in a comparative study.
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http://dx.doi.org/10.1097/00042737-200404000-00004DOI Listing
April 2004

Raloxifene concurrently stimulates osteoprotegerin and inhibits interleukin-6 production by human trabecular osteoblasts.

J Clin Endocrinol Metab 2003 Sep;88(9):4206-13

Department of Obstetrics and Gynecology, Georg-August-University of Goettingen, Goettingen, Germany D-37075.

Raloxifene reduces bone loss and prevents vertebral fractures in postmenopausal women. Its skeletal effects are mediated by estrogen receptors (ER) and their modulation of paracrine osteoblastic factors. Receptor activator of nuclear factor-kappa B ligand is essential for osteoclasts and enhances bone resorption, whereas osteoprotegerin (OPG) neutralizes receptor activator of nuclear factor-kappa B ligand. Here, we assessed the effects of raloxifene on OPG production in human osteoblasts (hOB). Raloxifene enhanced gene expression of ER-alpha and progesterone receptor. Moreover, raloxifene increased OPG mRNA levels and protein secretion by hOB in a dose- and time-dependent fashion by 2- to 4-fold with a maximum effect at 10(-7) M and after 72 h (P < 0.001). Treatment with the ER antagonist ICI 182,780 abrogated the effects of raloxifene on OPG production. Moreover, raloxifene enhanced osteoblastic differentiation markers, type 1 collagen secretion, and alkaline phosphatase activity by 3- and 2-fold, respectively (P < 0.001). In addition, raloxifene inhibited expression of the bone-resorbing cytokine IL-6 by 25-45% (P < 0.001). In conclusion, our data suggest that raloxifene stimulates OPG production and inhibits IL-6 production by hOB. Because OPG production increases with osteoblastic maturation, enhancement of OPG production by raloxifene could be related to its stimulatory effects on osteoblastic differentiation.
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http://dx.doi.org/10.1210/jc.2002-021877DOI Listing
September 2003

Cytokines, osteoprotegerin, and RANKL in vitro and histomorphometric indices of bone turnover in patients with different bone diseases.

J Bone Miner Res 2003 Mar;18(3):529-38

Department for Gastroenterology and Endocrinology, University Clinic of Göttingen, Göttingen, Germany.

Cytokines are supposed to play an essential role in the regulation of the bone metabolic unit. However, information on cytokine production of primary human osteoblasts from patients with metabolic bone disease is scarce, and few attempts have been made to correlate such data to histomorphometric parameters of individual patients. We investigated 11 patients with metabolic bone disease referred to our outpatient department for bone biopsy and analyzed interleukin (IL)-1, IL-6, and TNF-alpha protein release and gene expression in primary osteoblast cultures. Compared with four controls, five patients showed normal cytokine protein release, whereas six patients showed much higher levels of interleukin-6 (26-fold) and TNF-alpha (84-fold). All three cytokines were strongly correlated concerning gene expression and/or protein levels (r = 0.72-0.96). Histomorphometric analysis of the bone samples showed that eroded surface (ES/BS) as a parameter of bone resorption was significantly associated with TNF-a. In addition, RANKL gene expression was positively associated with ES/BS and osteoclast surface (Oc.S/BS). Finally, the formation parameters osteoid volume and osteoid surface were negatively associated with TNF-alpha. In conclusion, in an in vitro-ex vivo model of bone cells obtained from a group of 11 patients with different forms of metabolic bone disease, cytokine release in conditioned medium was significantly associated with bone resorption and bone formation, as quantified by histomorphometry. TNF-alpha seemed to be the more important cytokine; its effect on bone resorption could be mediated by RANKL.
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http://dx.doi.org/10.1359/jbmr.2003.18.3.529DOI Listing
March 2003

Differential regulation of Cbfa1/Runx2 and osteocalcin gene expression by vitamin-D3, dexamethasone, and local growth factors in primary human osteoblasts.

J Cell Biochem 2002 ;86(2):348-56

Department of Obstetrics and Gynecology, University of Goettingen, Germany.

Core binding factor alpha 1 (Cbfa1) is an osteoblast-specific transcription factor essential to develop a mature osteoblast phenotype. However, its exact role in the signaling of various osteotropic-differentiating agents is still unclear. In this study, we assessed the effects of 1,25-(OH)(2)-D3 (D3), ascorbic acid, bone morphogenetic protein-2 (BMP-2), dexamethasone (Dex), and transforming growth factor-beta (TGF-beta) on Cbfa1 and osteocalcin (OCN) mRNA steady state levels (by semiquantitative RT-PCR) in an in vitro model of osteoblast differentiation. TGF-beta increased Cbfa1 mRNA levels in normal primary human osteoblasts (pHOB) by 2.6-fold in a time-dependent fashion with maximum effect on day 28 (P < 0.001). Similarly, the glucocorticoid Dex enhanced Cbfa1 gene expression by pHOB in a time-dependent fashion by up to 4.6-fold (P < 0.001). In contrast, Dex inhibited OCN gene expression levels by 68% (P < 0.01). Treatment with BMP-2 resulted in an earlier enhancement of Cbfa1 and led to a 4.2-fold increase with a maximum on day 21 (P < 0.001). Ascorbic acid did not modulate Cbfa1 and OCN gene expression. The effect of vitamin D (D3) on Cbfa1 mRNA expression was influenced by the duration of treatment, being inhibitory after 1 h and having a stimulatory effect after 48 h. Time course experiments indicated a stimulatory effect of D3 on Cbfa1 mRNA levels (by 2.5-fold after 48 h; P < 0.01). Analysis of the late cellular differentiation marker osteocalcin revealed that D3 increased OCN gene expression by 14-fold (P < 0.001). In conclusion, in normal primary human osteoblasts, the rapid and pronounced increase of OCN after treatment with D3 seems not to be mediated by Cbfa1. These data imply that Cbfa1 gene expression is differentially regulated by various osteoblastic differentiating agents and is dependent on the stage of maturation.
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http://dx.doi.org/10.1002/jcb.10220DOI Listing
December 2002