@phdthesis{Joseph2011,
  author    = {Joseph, Julie},
  title     = {Studying the role of Th17 cells in autoimmune diabetes and generation of a beta cell reporter mouse by lentiviral transgenesis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-66571},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2011},
  abstract  = {Type 1 diabetes affects around 0.5\% of the population in developed countries and the incidence rates have been rising over the years. The destruction of beta cells is irreversible and the current therapy available to patients only manages the symptoms and does not prevent the associated pathological manifestations. The patients need lifelong therapy and intensive research is being carried out to identify ways to eliminate autoimmune responses directed against pancreatic beta cells and to replace or regenerate beta cells. The work presented herein aimed at analyzing the role of the Th17 T cell subset, characterized by secretion of the pro- inflammatory cytokine IL-17A, in autoimmune diabetes and also at generating a beta cell reporter mouse line in the NOD background, the most widely- used mouse model for type 1 diabetes. We generated IL- 17A knockdown (KD) NOD mice, using RNAi in combination with lentiviral transgenesis. We analyzed diabetes frequency in IL-17A deficient mice and found that the loss of IL-17A did not protect the transgenic mice from diabetes. Based on these observations, we believe that Th17 cells do not play a critical role in type 1 diabetes through the IL-17A pathway, though they might still be involved in the disease process through alternate pathways. We also generated NOD and NOD-SCID mice with a transgene that drives the beta cell specific expression of a luciferase reporter gene. We used a lentiviral construct, which combined a luciferase sequence and a short- hairpin RNA (shRNA) expression cassette, allowing gene- knockdown under the beta cell specific rat insulin promoter (RIP). These mice will be of use in studying beta cell phenotypes resulting from the knockdown of target genes, using non- invasive bioimaging. We believe that the generation of these reporter mouse lines for diabetes studies will prove valuable in future investigations. Furthermore, the demonstration that the loss of IL-17A does not alter susceptibility to type 1 diabetes should help clarify the controversial involvement of Th17 cells in this disease.},
  subject      = {Diabetes mellitus},
  language  = {en}
}
@phdthesis{Rikkala2015,
  author    = {Rikkala, Prashanth Reddy},
  title     = {Regulation of the Na+-D-glucose cotransporter SGLT1 in the small intestine in response to bariatric surgery and peptides derived from protein RS1 (RSC1A1)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130608},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2015},
  abstract  = {Bariatric surgery represents the first-line treatment for morbid obesity, resulting in weight loss and improved diabetes control. The positive effect of bariatric surgery on type-2 diabetes is unclear. Increased secretion of insulin regulating enterohormone glucagon-like-peptide 1 (GLP-1) has been observed in rats with experimental type 2-like diabetes following duodenal-jejunal bypass (DJB) and ileal transposition (IT). Sodium dependent glucose co-transporter (SGLT1) is involved in the secretion of GLP-1 that in turn regulates insulin secretion. In the present study, an attempt was made to elucidate the impact of DJB and IT on SGLT1 mediated glucose transport. Transport measurements using phlorizin inhibited uptake of SGLT1-specific glucose analogue [14C] α-Methyl-D-glucopyranoside (AMG) were performed to determine the changes in SGLT1 transport upon these surgical procedures. The data indicated that DJB decreased SGLT1-mediated glucose absorption in the small intestine which contributes to the body-weight independent improvement of type 2 diabetes. However, IT did not change the SGLT1-mediated glucose transport. Immunohistochemical analysis revealed that in IT, the transposed ileum showed increased diameter, increased villi length and increased number of GLP-1 secreting L-cells. The weight-independent improvement in glycemic control after IT is not related to SGLT1-mediated glucose absorption but may be linked to increased GLP-1 secretion. Along with this, the study also focused on the regulation of SGLT1 by several RS1 derived tripeptides in mouse and human intestinal tissues (ex vivo). Phlorizin inhibited uptake of AMG was measured without and with tripeptides. QEP and thiophosphorylated QSP down-regulated SGLT1 activity in small intestine in a concentration-dependent manner. Among the tested tripeptides, QEP showed higher activity and further analysis in various species demonstrated its universal role in SGLT1 regulation. The data thus indicates that RS1 derived tripeptides QEP and thiophosphorylated QSP may be employed for the treatment of type 2 diabetes.},
  subject      = {Glucosetransportproteine},
  language  = {en}
}
@article{RosenstockPerkovicAlexanderetal.2018,
  author    = {Rosenstock, Julio and Perkovic, Vlado and Alexander, John H. and Cooper, Mark E. and Marx, Nikolaus and Pencina, Michael J. and Toto, Robert D. and Wanner, Christoph and Zinman, Bernard and Baanstra, David and Pfarr, Egon and Mattheus, Michaela and Broedl, Uli C. and Woerle, Hans-J{\"u}rgen and George, Jyothis T. and von Eynatten, Maximilian and McGuire, Darren K.},
  title     = {Rationale, design, and baseline characteristics of the CArdiovascular safety and Renal Microvascular outcomE study with LINAgliptin - (CARMELINA®): a randomized, double-blind, placebo-controlled clinical trial in patients with type 2 diabetes and high cardio-renal risk},
  series = {Cardiovascular Diabetology},
  volume    = {17},
  journal   = {Cardiovascular Diabetology},
  doi       = {10.1186/s12933-018-0682-3},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226996},
  pages     = {39, 1-15},
  year      = {2018},
  abstract  = {Background: Cardiovascular (CV) outcome trials in type 2 diabetes (T2D) have underrepresented patients with chronic kidney disease (CKD), leading to uncertainty regarding their kidney efficacy and safety. The CARMELINA (R) trial aims to evaluate the effects of linagliptin, a DPP-4 inhibitor, on both CV and kidney outcomes in a study population enriched for cardio-renal risk. Methods: CARMELINA (R) is a randomized, double-blind, placebo-controlled clinical trial conducted in 27 countries in T2D patients at high risk of CV and/or kidney events. Participants with evidence of CKD with or without CV disease and HbA1c 6.5-10.0\% (48-86 mmol/mol) were randomized 1:1 to receive linagliptin once daily or matching placebo, added to standard of care adjusted according to local guidelines. The primary outcome is time to first occurrence of CV death, non-fatal myocardial infarction, or non-fatal stroke. The key secondary outcome is a composite of time to first sustained occurrence of end-stage kidney disease, >= 40\% decrease in estimated glomerular filtration rate (eGFR) from baseline, or renal death. CV and kidney events are prospectively adjudicated by independent, blinded clinical event committees. CARMELINA (R) was designed to continue until at least 611 participants had confirmed primary outcome events. Assuming a hazard ratio of 1.0, this provides 90\% power to demonstrate non-inferiority of linagliptin versus placebo within the pre-specified non-inferiority margin of 1.3 at a one-sided a-level of 2.5\%. If non-inferiority of linagliptin for the primary outcome is demonstrated, then its superiority for both the primary outcome and the key secondary outcome will be investigated with a sequentially rejective multiple test procedure. Results: Between July 2013 and August 2016, 6980 patients were randomized and took >= 1 dose of study drug (40.6, 33.1, 16.9, and 9.4\% from Europe, South America, North America, and Asia, respectively). At baseline, mean +/- SD age was 65.8 +/- 9.1 years, HbA1c 7.9 +/- 1.0\%, BMI 31.3 +/- 5.3 kg/m(2), and eGFR 55 +/- 25 mL/min/1.73 m(2). A total of 5148 patients (73.8\%) had prevalent kidney disease (defined as eGFR < 60 mL/min/1.73 m(2) or macroalbuminuria [albumin-to-creatinine ratio > 300 mg/g]) and 3990 patients (57.2\%) had established CV disease with increased albuminuria; these characteristics were not mutually exclusive. Microalbuminuria (n = 2896 [41.5\%]) and macroalbuminuria (n = 2691 [38.6\%]) were common. Conclusions: CARMELINA (R) will add important information regarding the CV and kidney disease clinical profile of linagliptin by including an understudied, vulnerable cohort of patients with T2D at highest cardio-renal risk.},
  language  = {en}
}
@phdthesis{Zheng2012,
  author    = {Zheng, Peilin},
  title     = {Ptpn22 silencing in the NOD model of type 1 diabetes indicates the human susceptibility allele of PTPN22 is a gain-of-function variant},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-73869},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2012},
  abstract  = {PTPN22 encodes the lymphoid tyrosine phosphatase Lyp that can dephosphorylate Lck, ZAP-70 and Fyn to attenuate TCR signaling. A single-nucleotide polymorphism (C1858T) causes a substitution from arginine (R) to tryptophan (W) at 620 residue (R620W). Lyp-620W has been confirmed as a susceptible allele in multiple autoimmune diseases, including type 1 diabetes (T1D). Several independent studies proposed that the disease-associated allele is a gain-of-function variant. However, a recent report found that in human cells and a knockin mouse containing the R620W homolog that Ptpn22 protein degradation is accelerated, indicating Lyp-620W is a loss-of-function variant. Whether Lyp R620W is a gain- or loss-of-function variant remains controversial. To resolve this issue, we generated two lines (P2 and P4) of nonobese diabetic (NOD) mice in which Ptpn22 can be inducibly silenced by RNAi. We found long term silencing of Ptpn22 increased spleen cellularity and regulatory T (Treg) cell numbers, replicating the effect of gene deletion reported in the knockout (KO) B6 mice. Notably, Ptpn22 silencing also increased the reactivity and apoptotic behavior of B lymphocytes, which is consistent with the reduced reactivity and apoptosis of human B cells carrying the alleged gain-of-function PTPN22 allele. Furthermore, loss of Ptpn22 protected P2 KD mice from spontaneous and Cyclophosphamide (CY) induced diabetes. Our data support the notion that Lyp-620W is a gain-of-function variant. Moreover, Lyp may be a valuable target for the treatment of autoimmune diseases.},
  subject      = {Diabetes mellitus},
  language  = {en}
}
@phdthesis{Dirimanov2019,
  author    = {Dirimanov, Stoyan Dinkov},
  title     = {Molecular Effects of Polyphenols in Experimental Type 2 Diabetes Mellitus and Metabolic Syndrome},
  doi       = {10.25972/OPUS-18570},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-185701},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2019},
  abstract  = {The growing prevalence of type 2 diabetes mellitus (T2DM) demands novel therapeutic and adjuvant strategies. Polyphenols (PPs) are plant secondary metabolites. Epidemiological studies demonstrate an inverse relationship between their increased intake and the risk of development of T2DM and cardiovascular complications. However, the PPs' mechanism of action remains largely unknown. The present work aimed to expand knowledge regarding the effects of PPs on diabetes relevant molecular targets. Pycnogenol® (PYC) is a standardized pine bark extract which consists of oligomeric and monomeric PPs. Its anti-diabetic effects have been demonstrated in clinical trials. As a part of a human study involving 20 healthy volunteers, the extract's effects on dipeptidyl peptidase IV (DPP IV) were investigated. This protease terminates the insulin secretagogue action of incretins. Its inhibition is a promising strategy in T2DM treatment. This study uncovered that PYC-intake of 100 mg daily over 14 days statistically significantly reduced DPP IV serum concentrations by 8.2 \% (n= 38, p= 0.032). Contrary to expectations, this decrease was not paralleled by a reduction in the serum DPP IV enzymatic activity. To the best of our knowledge, the present study was the first investigating the effects of PPs on DPP IV serum concentrations and activities in humans. The finding that PYC is capable of reducing DPP IV serum concentrations might be important with regard to diabetes, where DPP IV levels are increased. Screenings for PPs' in vitro effects on DPP IV activity were performed employing a purified enzyme. The effects of tested PPs (among which PYC ingredients) at a physiologically relevant concentration of 5 µM were weak (< 10 \%) and too small compared to the reference compound sitagliptin, and thus not likely to be clinically relevant. This result is in discordance with some published data, but consistent with the outcome from the present human study. In addition, fluorescence interactions with the experimental setup were registered: under certain conditions urolithin B exhibited an autofluorescence which might mask eventual inhibitory activity. Quercetin quenched the fluorescence slightly which might contribute to false positive results. No statistically significant effects of selected constituents and metabolites of PYC on the total DPP IV protein expression were observed in 3T3-L1 adipocytes. Thus, the lower DPP IV in vivo concentrations after intake of PYC cannot be explained with down-regulation of the DPP IV expression in adipocytes. Akt kinase is responsible for the transmission of insulin signals and its dysregulation is related to insulin resistance and plays an important role in development of cardiovascular complications in T2DM. Thus, the modulation of the phosphorylation status of endothelial Akt-kinase, respectively its activity, might be a promising strategy in the management of these pathologies. This work aimed to uncover the effects of PPs from different structural subclasses on Akt-phosphorylation (pAkt) in endothelial cells (Ea.hy926). Short-term effects (5 - 30 min) were investigated at a concentration of 10 µM. In a pilot study two model PPs induced a moderate, but reproducible inhibition of pAkt Ser473 of 52.37 ± 21.01 \% (quercetin; p= 0.006, n= 3) and 37.79 ± 7.14 \% (resveratrol; p= 0.021, n= 4) compared to the negative control. A primary screening with Western blot analysis investigated the effects of eight compounds from different subclasses on pAkt Ser473 and Thr308 to reveal whether the observed inhibition PPs a group effect or specific to certain compounds. In addition to resveratrol and quercetin, statistically significant inhibitions of pAkt Ser473 were induced by luteolin (29.96 ± 11.06 \%, p< 0.01, n= 6) and apigenin (22.57 ± 10.30 \%, p< 0.01, n= 6). In contrast, genistein, 3,4,5-trimethoxystilbene, taxifolin and (+)-catechin caused no inhibition. A strong positive and statistically significant correlation between the mean inhibitory effects of the tested PPs on both Akt-residues Ser473 and Thr308 (r= 0.9478, p= 0.0003) was determined. A comprehensive secondary screening via ELISA involving 44 compounds from nine structural groups quantified the effects of PPs on pAkt Ser473 to uncover potential structure-activity features. The most potent inhibitors were luteolin (44.31 ± 17.95 \%), quercetin (35.71 ± 8.33 \%), urolithin A (35.28 ± 11.80 \%), apigenin (31.79 ± 6.16 \%), fisetin (28.09 ± 9.09 \%), and resveratrol (26.04 ± 5.58 \%). These effects were statistically significant (p< 0.01, n= 3 to 6). Further lead structure optimization might be based on the fact that the effects of luteolin and resveratrol also differed statistically significantly from each other (p= 0.008). To the best of our knowledge, the present study is the first to compare quantitatively the short term effects of PPs from different subclasses on pAkt in endothelial cells. Basic structure-activity relationships revealed that for flavones and flavonols the presence of a C2=C3 double bond (ring C) was essential for inhibitory activity and hydroxylation on the m- and p- positions in the ring B contributed to it. For stilbenoids, three free OH-groups appeared to be optimal. The comparison of the inhibitory potentials of ellagic acid and its microbial metabolites showed that urolithin A was statistically significantly more effective than its progenitor compound. Despite their structural similarities, the only active compound among all urolithins tested was urolithin A, hydroxylated at the C3 and C8 positions. This suggested a specific effect for urolithin A. Based on the common structural determinants and molecular geometry of the most active PPs a pharmacophore model regarding Akt-inhibition was proposed. In summary, the effects of a wide variety of PPs from diverse structural subclasses on the in vitro phosphorylation of endothelial Akt were quantitatively analyzed for the first time, the effects of previously undescribed compounds were determined and structure activity relationships were elucidated. The inhibitory potential of individual PPs might be beneficial in cases of sustained over-activation of Akt-kinase and its substrates such as S6 kinase as reported for certain T2DM-related pathological states, such as insulin resistance, endothelial dysfunction, excessive angiogenesis, vascular calcification, and insulin triggered DNA-damage. The results of the present work suggest potential molecular mechanisms of action of PP involving Akt-inhibition and DPP IV-down-regulation and thus contribute to the understanding of anti-diabetic effects of these compounds on the molecular level.},
  subject      = {Polyphenole},
  language  = {en}
}
@phdthesis{Muehlemann2018,
  author    = {M{\"u}hlemann, Markus},
  title     = {Intestinal stem cells and the Na\(^+\)-D-Glucose Transporter SGLT1: potential targets regarding future therapeutic strategies for diabetes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169266},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2018},
  abstract  = {The pancreas and the small intestine are pivotal organs acting in close synergism to regulate glucose metabolism. After absorption and processing of dietary glucose within the small intestine, insulin and glucagon are released from pancreatic islet cells to maintain blood glucose homeostasis. Malfunctions affecting either individual, organ-specific functions or the sophisticated interplay of both organs can result in massive complications and pathologic conditions. One of the most serious metabolic diseases of our society is diabetes mellitus (DM) that is hallmarked by a disturbance of blood glucose homeostasis. Type 1 (T1DM) and type 2 (T2DM) are the main forms of the disease and both are characterized by chronic hyperglycemia, a condition that evokes severe comorbidities in the long-term. In the past, several standard treatment options allowed a more or less adequate therapy for diabetic patients. Albeit there is much effort to develop new therapeutic interventions to treat diabetic patients in a more efficient way, no cure is available so far. In view of the urgent need for alternative treatment options, a more systemic look on whole organ systems, their biological relation and complex interplay is needed when developing new therapeutic strategies for DM. T1DM is hallmarked by an autoimmune-mediated destruction of the pancreatic β-cell mass resulting in a complete lack of insulin that is in most patients restored by applying a life-long recombinant insulin therapy. Therefore, novel regenerative medicine-based concepts focus on the derivation of bioartificial β-like cells from diverse stem cell sources in vitro that survive and sustain to secrete insulin after implantation in vivo. In this context, the first part of this thesis analyzed multipotent intestinal stem cells (ISCs) as alternative cell source to derive bioartificial, pancreatic β-like cells in vitro. From a translational perspective, intestinal stem cells pose a particularly attractive cell source since intestinal donor tissues could be obtained via minimal invasive endoscopy in an autologous way. Furthermore, intestinal and pancreatic cells both derive from the same developmental origin, the endodermal gut tube, favoring the differentiation process towards functional β-like cells. In this study, pancreas-specific differentiation of ISCs was induced by the ectopic expression of the pancreatic transcription factor 1 alpha (Ptf1a), a pioneer transcriptional regulator of pancreatic fate. Furthermore, pancreatic lineage-specific culture media were applied to support the differentiation process. In general, ISCs grow in vitro in a 3D Matrigel®-based environment. Therefore, a 2D culture platform for ISCs was established to allow delivery and ectopic expression of Ptf1a with high efficiency. Next, several molecular tools were applied and compared with each other to identify the most suitable technology for Ptf1a delivery and expression within ISCs as well as their survival under the new established 2D conditions. Success of differentiation was investigated by monitoring changes in cellular morphology and induction of pancreatic differentiation-specific gene expression profiles. In summary, the data of this project part suggest that Ptf1a harbors the potential to induce pancreatic differentiation of ISCs when applying an adequate differentiation media. However, gene expression analysis indicated rather an acinar lineage-determination than a pancreatic β-cell-like specification. Nevertheless, this study proved ISCs not only as interesting stem cell source for the generation of pancreatic cell types with a potential use in the treatment of T1DM but alsoPtf1a as pioneer factor for pancreatic differentiation of ISCs in general. Compared to T1DM, T2DM patients suffer from hyperglycemia due to insulin resistance. In T2DM management, the maintenance of blood glucose homeostasis has highest priority and can be achieved by drugs affecting the stabilization of blood glucose levels. Recent therapeutic concepts are aiming at the inhibition of the intestinal glucose transporter Na+-D-Glucose cotransporter 1 (SGLT1). Pharmacological inhibition of SGLT1 results in reduced postprandial blood glucose levels combined with a sustained and increased Glucagon-like peptide 1 (GLP-1) secretion. So far, systemic side effects of this medication have not been addressed in detail. Of note, besides intestinal localization, SGLT1 is also expressed in various other tissues including the pancreas. In context of having a closer look also on the interplay of organs when developing new therapeutic approaches for DM, the second part of this thesis addressed the effects on pancreatic islet integrity after loss of SGLT1. The analyses comprised the investigation of pancreatic islet size, cytomorphology and function by the use of a global SGLT1 knockout (SGLT1-/-) mouse model. As SGLT1-/- mice develop the glucose-galactose malabsorption syndrome when fed a standard laboratory chow, these animals derived a glucose-deficient, fat-enriched (GDFE) diet. Wildtype mice on either standard chow (WTSC) or GDFE (WTDC) allowed the discrimination between diet- and knockout-dependent effects. Notably, GDFE fed mice showed decreased expression and function of intestinal SGLT1, while pancreatic SGLT1 mRNA levels were unaffected. Further, the findings revealed increased isled sizes, reduced proliferation- and apoptosis rates as well as an increased α-cell and reduced β-cell proportion accompanied by a disturbed cytomorphology in islets when SGLT1 function is lost or impaired. In addition, pancreatic islets were dysfunctional in terms of insulin- and glucagon-secretion. Moreover, the release of intestinal GLP-1, an incretin hormone that stimulates insulin-secretion in the islet, was abnormal after glucose stimulatory conditions. In summary, these data show that intestinal SGLT1 expression and function is nutrient dependent. The data obtained from the islet studies revealed an additional and new role of SGLT1 for maintaining pancreatic islet integrity in the context of structural, cytomorphological and functional aspects. With special emphasis on SGLT1 inhibition in diabetic patients, the data of this project indicate an urgent need for analyzing systemic side effects in other relevant organs to prove pharmacological SGLT1 inhibition as beneficial and safe. Altogether, the findings of both project parts of this thesis demonstrate that focusing on the molecular and cellular relationship and interplay of the small intestine and the pancreas could be of high importance in context of developing new therapeutic strategies for future applications in DM patients.},
  subject      = {Stammzelle},
  language  = {en}
}
@phdthesis{Kehlenbrink2010,
  author    = {Kehlenbrink, Sylvia},
  title     = {Inhibiting Gluconeogenesis (GNG) Prevents the Effects of Free Fatty Acids (FFA) on Hepatic Glucose Effectiveness (GE)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-48389},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2010},
  abstract  = {Free fatty acids (FFA) modulate the effectiveness of glucose to suppress endogenous glucose production (EGP), and increased FFA levels contribute importantly to the loss of glucose effectiveness in type 2 diabetes mellitus (T2DM). Elevating FFA levels in nondiabetic (ND) subjects for at least 6h both increases gluconeogenesis (GNG) and impairs glucose effectiveness. Therefore, we wished to define the extent to which an increase in GNG is responsible for the loss of glucose effectiveness and whether EGP can be inhibited in the presence of elevated plasma FFA by inhibiting GNG with ethanol. To determine the effect of inhibiting GNG on glucose effectiveness, EGP ([3-3H]-glucose) was measured during three separate 7h normoglycemic/hyperglycemic pancreatic clamp studies (somatostatin; basal glucagon/GH/insulin replacement) in n=7 ND subjects (1F/6M; age=45±5 yr; BMI=27.6±3.0 kg/m2). Following an initial 210 min interval of euglycemia (5 mmol/l), blood glucose levels were raised to hyperglycemic levels (10 mmol/l) from t=210-420 min. The first pancreatic clamp study was a baseline study with saline infusions (Lip-/Et-). Lipid emulsion (Liposyn 20\%) was infused throughout the second and third study types (Lip+ and Lip+/Et+) to increase FFA to T2DM levels (~ 500 mmol/l). In addition to Liposyn, ethanol (Et) was infused during hyperglycemia in the third study type (Lip+/Et+), using a pharmacokinetic algorithm to attain GNG-inhibiting ethanol levels of 80 mg/dl within 20 min. Under baseline conditions, hyperglycemia suppressed EGP by 61\%. After raising plasma FFA to T2DM levels, suppression of EGP by hyperglycemia was impaired in Lip+ (34\% decrease). During the Lip+/Et+ co-infusion studies the infusion of ethanol enhanced suppression of EGP by hyperglycemia (65.8\% decrease, P=0.004 vs. Lip+) and thus restored glucose effectiveness (P=0.6 vs. Lip-/Et-). Thus, our results confirm the striking effects of elevated plasma FFA to impair glucose effectiveness and suggest that increased GNG contributes importantly to this loss of regulation. Inhibiting GNG could be an effective means of lowering EGP and improving glucose effectiveness in T2DM.},
  subject      = {Gluconeogenese},
  language  = {en}
}
@phdthesis{Bartl2012,
  author    = {Bartl, Jasmin},
  title     = {Impairment of insulin signaling pathway in Alzheimer's disease},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-74197},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2012},
  abstract  = {The neurodegenerative disorder Alzheimer's disease (AD) is the cause of approximately 60\% of the world's 35 million patients suffering from dementia. Current research focuses here are on association with other diseases such as diabetes type 2 (T2DM), possible genetic markers, specific signal transduction pathways within the brain and potential protein modification, because the pathogenesis and etiology of AD are still not fully understood. Specifically association of T2DM with AD came to the focus with the so-called "Rotterdam study" in 1999, indicating that T2DM doubles the risk of developing AD. In the meantime, it is known that the prevalence rate in patients with T2DM is 30\%. Drugs commonly used in the treatment of T2DM such as peroxisome proliferator-activated receptors gamma (PPARγ) agonists show improvement of the cognitive abilities in patients with early stage of dementia, with potential therapeutically relevance. Therefore it is important not only to investigate a link between these diseases, but also to investigate the insulin signaling pathway in the brain of AD patients. In order to investigate this complex issue in more details and demonstrate additional links between T2DM and AD, the present study used several basic biological methods to clarify the question: "Is impaired insulin signaling pathway within the brain crucial for the development of AD?" from several points of view. The methods used in this work have been i) an analysis of single nucleotide (SNP) polymorphism of the insulin-degrading enzyme gene (IDE) in relation to risk of AD and / or of T2DM, ii) post-mortem histochemical studies of brain tissue of patients with only AD, with AD combined with T2DM and with only T2DM compared with an age-matched control group, and iii.) investigations of neurochemical pathways and gene/protein expression changes of a human cell culture as a consequences of amyloid β (Aβ) treatment. After analysis of the IDE SNP polymorphism in the selected VITA (Vienna Trans Danube Aging) cohort disease-specific effects were discovered. The upstream polymorphism (IDE2) was found to influence AD risk in a protective manner, while the downstream polymorphism (IDE7) modified the T2DM risk. Based on the SNP results, the presented study delineate the model that IDE promoter and 3‟ untranslated region/downstream variation can have different effects on IDE expression, maybe a relevant endophenotype with disorder-specific effects on AD and T2DM susceptibility. Furthermore, the human post-mortem studies could show that both AD as well as T2DM patients had a significantly lower density of the insulin receptor (IR) in the hippocampus, whereas a significantly increased density of inactive phosphorylated PPARγ has been found and this persisted even in patients with both diseases. Summarizing the histological study, it was possible to reveal common histological features of AD and T2DM, but no direct connection between the two diseases. Although AD is nowadays not only characterized by amyloid-containing plaque deposits and by the hyperphosphorylation of tau protein, the excessive Aβ42 presence in the brains of AD patients is still playing a key role. Up to date it is still not entirely clear which physical form of Aβ42 is responsible for the development of AD. The present work investigated, what impact has the state of aggregation of Aβ42 on genes and proteins of the insulin signaling pathway and the amyloid cascade. It could be shown that the oligomeric variant enhanced specifically the gene and protein expression of glycogen synthase kinase (GSK) 3β and also the enzyme activity was significantly increased, but has in turn strongly inhibited the IR gene and protein expression. Additionally, the effect of Aβ42 on monoamine oxidase B (MAO-B) was examined. An effect of both aggregated forms of Aβ42 had on enzyme activity was discovered. However, the fibrillar variants led to significantly increased activity of MAO-B while the oligomeric variants inhibited the enzyme activity. Several previous studies have demonstrated the involvement of increased MAO-B activity in AD, but the present work provides for the first time a direct link between the states of aggregation of Aβ42 to enzyme activity. Finally the results of the presented thesis can be summarized to following conclusion: Although AD and T2DM sharing some degrees of common features, still there is a lack of direct association, and therefore the diseases must be considered more independent rather than linked. But the impaired cerebral insulin signaling pathway seems to be another manifested hallmark of AD.},
  subject      = {Alzheimer-Krankheit},
  language  = {en}
}
@article{BuschNadalSchmidetal.2016,
  author    = {Busch, Martin and Nadal, Jennifer and Schmid, Matthias and Paul, Katharina and Titze, Stephanie and H{\"u}bner, Silvia and K{\"o}ttgen, Anna and Schultheiss, Ulla T. and Baid-Agrawal, Seema and Lorenzen, Johan and Schlieper, Georg and Sommerer, Claudia and Krane, Vera and Hilge, Robert and Kielstein, Jan T. and Kronenberg, Florian and Wanner, Christoph and Eckardt, Kai-Uwe and Wolf, Gunter},
  title     = {Glycaemic control and antidiabetic therapy in patients with diabetes mellitus and chronic kidney disease - cross-sectional data from the German Chronic Kidney Disease (GCKD) cohort},
  series = {BMC Nephrology},
  volume    = {17},
  journal   = {BMC Nephrology},
  number    = {59},
  doi       = {10.1186/s12882-016-0273-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-164687},
  year      = {2016},
  abstract  = {Background Diabetes mellitus (DM) is the leading cause of end-stage renal disease. Little is known about practice patterns of anti-diabetic therapy in the presence of chronic kidney disease (CKD) and correlates with glycaemic control. We therefore aimed to analyze current antidiabetic treatment and correlates of metabolic control in a large contemporary prospective cohort of patients with diabetes and CKD. Methods The German Chronic Kidney Disease (GCKD) study enrolled 5217 patients aged 18-74 years with an estimated glomerular filtration rate (eGFR) between 30-60 mL/min/1.73 m2 or proteinuria >0.5 g/d. The use of diet prescription, oral anti-diabetic medication, and insulin was assessed at baseline. HbA1c, measured centrally, was the main outcome measure. Results At baseline, DM was present in 1842 patients (35 \%) and the median HbA1C was 7.0 \% (25th-75th percentile: 6.8-7.9 \%), equalling 53 mmol/mol (51, 63); 24.2 \% of patients received dietary treatment only, 25.5 \% oral antidiabetic drugs but not insulin, 8.4 \% oral antidiabetic drugs with insulin, and 41.8 \% insulin alone. Metformin was used by 18.8 \%. Factors associated with an HbA1C level >7.0 \% (53 mmol/mol) were higher BMI (OR = 1.04 per increase of 1 kg/m2, 95 \% CI 1.02-1.06), hemoglobin (OR = 1.11 per increase of 1 g/dL, 95 \% CI 1.04-1.18), treatment with insulin alone (OR = 5.63, 95 \% CI 4.26-7.45) or in combination with oral antidiabetic agents (OR = 4.23, 95 \% CI 2.77-6.46) but not monotherapy with metformin, DPP-4 inhibitors, or glinides. Conclusions Within the GCKD cohort of patients with CKD stage 3 or overt proteinuria, antidiabetic treatment patterns were highly variable with a remarkably high proportion of more than 50 \% receiving insulin-based therapies. Metabolic control was overall satisfactory, but insulin use was associated with higher HbA1C levels.},
  language  = {en}
}
@article{AppeltshauserMessingerStarzetal.2022,
  author    = {Appeltshauser, Luise and Messinger, Julia and Starz, Katharina and Heinrich, David and Brunder, Anna-Michelle and Stengel, Helena and Fiebig, Bianca and Ayzenberg, Ilya and Birklein, Frank and Dresel, Christian and Dorst, Johannes and Dvorak, Florian and Grimm, Alexander and Joerk, Alexander and Leypoldt, Frank and M{\"a}urer, Mathias and Merl, Patrick and Michels, Sebastian and Pitarokoili, Kalliopi and Rosenfeldt, Mathias and Sperfeld, Anne-Dorte and Weihrauch, Marc and Welte, Gabriel Simon and Sommer, Claudia and Doppler, Kathrin},
  title     = {Diabetes Mellitus Is a Possible Risk Factor for Nodo-paranodopathy With Antiparanodal Autoantibodies},
  series = {Neurology: Neuroimmunology \& Neuroinflammation},
  volume    = {9},
  journal   = {Neurology: Neuroimmunology \& Neuroinflammation},
  number    = {3},
  doi       = {10.1212/NXI.0000000000001163},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300551},
  year      = {2022},
  abstract  = {Background and Objectives Nodo-paranodopathies are peripheral neuropathies with dysfunction of the node of Ranvier. Affected patients who are seropositive for antibodies against adhesion molecules like contactin-1 and neurofascin show distinct clinical features and a disruption of the paranodal complex. An axoglial dysjunction is also a characteristic finding of diabetic neuropathy. Here, we aim to investigate a possible association of antibody-mediated nodo-paranodopathy and diabetes mellitus (DM). Methods We retrospectively analyzed clinical data of 227 patients with chronic inflammatory demyelinating polyradiculoneuropathy and Guillain-Barr{\´e} syndrome from multiple centers in Germany who had undergone diagnostic testing for antiparanodal antibodies targeting neurofascin-155, pan-neurofascin, contactin-1-associated protein 1, and contactin-1. To study possible direct pathogenic effects of antiparanodal antibodies, we performed immunofluorescence binding assays on human pancreatic tissue sections. Results The frequency of DM was 33.3\% in seropositive patients and thus higher compared with seronegative patients (14.1\%, OR = 3.04, 95\% CI = 1.31-6.80). The relative risk of DM in seropositive patients was 3.4-fold higher compared with the general German population. Seropositive patients with DM most frequently harbored anti-contactin-1 antibodies and had higher antibody titers than seropositive patients without DM. The diagnosis of DM preceded the onset of neuropathy in seropositive patients. No immunoreactivity of antiparanodal antibodies against pancreatic tissue was detected. Discussion We report an association of nodo-paranodopathy and DM. Our results suggest that DM may be a potential risk factor for predisposing to developing nodo-paranodopathy and argue against DM being induced by the autoantibodies. Our findings set the basis for further research investigating underlying immunopathogenetic connections.},
  language  = {en}
}