• Amyloid arthropathy associated with multiple myeloma: polyarthritis without synovial infiltration of CD20+ or CD38+ cells.

      Pessler, Frank; Ogdie, Alexis R; Mayer, Christian T; Kretzschmar, Warren W; Dai, Lie; Elsaman, Ahmed M; Einhorn, Eugene; Krenn, Veit; Schumacher, H Ralph (2014-03)
      To describe histological, immunohistochemical and ultrastructural features of synovial biopsies of amyloid arthropathy associated with multiple myeloma (MM).
    • Analysis of contingency tables based on generalised median polish with power transformations and non-additive models

      Klawonn, Frank; Jayaram, Balasubramaniam; Crull, Katja; Kukita, Akiko; Pessler, Frank (2013-05-30)
      Abstract Contingency tables are a very common basis for the investigation of effects of different treatments or influences on a disease or the health state of patients. Many journals put a strong emphasis on p-values to support the validity of results. Therefore, even small contingency tables are analysed by techniques like t-test or ANOVA. Both these concepts are based on normality assumptions for the underlying data. For larger data sets, this assumption is not so critical, since the underlying statistics are based on sums of (independent) random variables which can be assumed to follow approximately a normal distribution, at least for a larger number of summands. But for smaller data sets, the normality assumption can often not be justified. Robust methods like the Wilcoxon-Mann-Whitney-U test or the Kruskal-Wallis test do not lead to statistically significant p-values for small samples. Median polish is a robust alternative to analyse contingency tables providing much more insight than just a p-value. Median polish is a technique that provides more information than just a p-value. It explains the contingency table in terms of an overall effect, row and columns effects and residuals. The underlying model for median polish is an additive model which is sometimes too restrictive. In this paper, we propose two related approach to generalise median polish. A power transformation can be applied to the values in the table, so that better results for median polish can be achieved. We propose a graphical method how to find a suitable power transformation. If the original data should be preserved, one can apply other transformations – based on so-called additive generators – that have an inverse transformation. In this way, median polish can be applied to the original data, but based on a non-additive model. The non-linearity of such a model can also be visualised to better understand the joint effects of rows and columns in a contingency table.
    • Anti-nuclear autoantibodies in the general German population: prevalence and lack of association with selected cardiovascular and metabolic disorders-findings of a multicenter population-based study.

      Akmatov, Manas K; Röber, Nadja; Ahrens, Wolfgang; Flesch-Janys, Dieter; Fricke, Julia; Greiser, Halina; Günther, Kathrin; Kaaks, Rudolf; Kemmling, Yvonne; Krone, Bastian; et al. (2017-06-06)
      We determined the prevalence of anti-nuclear autoantibodies (ANAs) in the German adult population and examined the association between ANAs and cardiovascular and metabolic disorders.
    • Comparison of response patterns in different survey designs: a longitudinal panel with mixed-mode and online-only design.

      Rübsamen, Nicole; Akmatov, Manas K; Castell, Stefanie; Karch, André; Mikolajczyk, Rafael T; Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2017)
      Increasing availability of the Internet allows using only online data collection for more epidemiological studies. We compare response patterns in a population-based health survey using two survey designs: mixed-mode (choice between paper-and-pencil and online questionnaires) and online-only design (without choice).
    • Congenital deficiency reveals critical role of ISG15 in skin homeostasis.

      Malik, Muhammad Nasir Hayat; Waqas, Syed F Hassnain; Zeitvogel, Jana; Cheng, Jingyuan; Geffers, Robert; Gouda, Zeinab Abu-Elbaha; Elsaman, Ahmed Mahrous; Radwan, Ahmed R; Schefzyk, Matthias; Braubach, Peter; et al. (Society of clinical investigation, 2021-11-30)
      Ulcerating skin lesions are manifestations of human ISG15 deficiency, a type I interferonopathy. However, chronic inflammation may not be their exclusive cause. We describe two siblings with recurrent skin ulcers that healed with scar formation upon corticosteroid treatment. Both had a homozygous nonsense mutation in the ISG15 gene, leading to unstable ISG15 protein lacking the functional domain. We characterized ISG15-/- dermal fibroblasts, HaCaT keratinocytes, and human induced pluripotent stem cell-derived vascular endothelial cells. ISG15-deficient cells exhibited the expected hyperinflammatory phenotype, but also dysregulated expression of molecules critical for connective tissue and epidermis integrity, including reduced collagens and adhesion molecules, but increased matrix metalloproteases. ISG15-/- fibroblasts exhibited elevated ROS levels and reduced ROS scavenger expression. As opposed to hyperinflammation, defective collagen and integrin synthesis was not rescued by conjugation-deficient ISG15. Cell migration was retarded in ISG15-/- fibroblasts and HaCaT keratinocytes, but normalized under ruxolitinib treatment. Desmosome density was reduced in an ISG15-/- 3D epidermis model. Additionally, there were loose architecture and reduced collagen and desmoglein expression, which could be reversed by treatment with ruxolitinib/doxycycline/TGF-β1. These results reveal critical roles of ISG15 in maintaining cell migration and epidermis and connective tissue homeostasis, whereby the latter likely requires its conjugation to yet unidentified targets.
    • Corticosteroid-induced spinal epidural lipomatosis in the pediatric age group: report of a new case and updated analysis of the literature

      Möller, Jana C; Cron, Randy Q; Young, Daniel W; Girschick, Hermann J; Levy, Deborah M; Sherry, David D; Kukita, Akiko; Saijo, Kaoru; Pessler, Frank (2011-02-01)
      Abstract Spinal epidural lipomatosis is a rare complication of chronic corticosteroid treatment. We report a new pediatric case and an analysis of this and 19 pediatric cases identified in the international literature. The youngest of these combined 20 patients was 5 years old when lipomatosis was diagnosed. Lipomatosis manifested after a mean of 1.3 (+/- 1.5) years (SD) (median, 0.8 years; range, 3 weeks - 6.5 years) of corticosteroid treatment. The corticosteroid dose at the time of presentation of the lipomatosis ranged widely, between 5 and 80 mg of prednisone/day. Back pain was the most common presenting symptom. Imaging revealed that lipomatosis almost always involved the thoracic spine, extending into the lumbosacral region in a subset of patients. Predominantly lumbosacral involvement was documented in only two cases. Although a neurological deficit at presentation was documented in about half of the cases, surgical decompression was not performed in the cases reported after 1996. Instead, reducing the corticosteroid dose (sometimes combined with dietary restriction to mobilize fat) sufficed to induce remission. In summary, pediatric spinal epidural lipomatosis remains a potentially serious untoward effect of corticosteroid treatment, which, if recognized in a timely manner, can have a good outcome with conservative treatment.
    • Corticosteroid-induced spinal epidural lipomatosis in the pediatric age group: report of a new case and updated analysis of the literature.

      Möller, Jana C; Cron, Randy Q; Young, Daniel W; Girschick, Hermann J; Levy, Deborah M; Sherry, David D; Kukita, Akiko; Saijo, Kaoru; Pessler, Frank; Helmholtz Centre for infection research, Inhoffenstr. 7, D-38124 Braunschweig, Germany. (2011)
      Spinal epidural lipomatosis is a rare complication of chronic corticosteroid treatment. We report a new pediatric case and an analysis of this and 19 pediatric cases identified in the international literature. The youngest of these combined 20 patients was 5 years old when lipomatosis was diagnosed. Lipomatosis manifested after a mean of 1.3 (+/- 1.5) years (SD) (median, 0.8 years; range, 3 weeks - 6.5 years) of corticosteroid treatment. The corticosteroid dose at the time of presentation of the lipomatosis ranged widely, between 5 and 80 mg of prednisone/day. Back pain was the most common presenting symptom. Imaging revealed that lipomatosis almost always involved the thoracic spine, extending into the lumbosacral region in a subset of patients. Predominantly lumbosacral involvement was documented in only two cases. Although a neurological deficit at presentation was documented in about half of the cases, surgical decompression was not performed in the cases reported after 1996. Instead, reducing the corticosteroid dose (sometimes combined with dietary restriction to mobilize fat) sufficed to induce remission. In summary, pediatric spinal epidural lipomatosis remains a potentially serious untoward effect of corticosteroid treatment, which, if recognized in a timely manner, can have a good outcome with conservative treatment.
    • Crystal structure of -aconitate decarboxylase reveals the impact of naturally occurring human mutations on itaconate synthesis.

      Chen, Fangfang; Lukat, Peer; Iqbal, Azeem Ahmed; Saile, Kyrill; Kaever, Volkhard; van den Heuvel, Joop; Blankenfeldt, Wulf; Büssow, Konrad; Pessler, Frank; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (National Academy of Sciences, 2019-09-23)
      cis-Aconitate decarboxylase (CAD, also known as ACOD1 or Irg1) converts cis-aconitate to itaconate and plays central roles in linking innate immunity with metabolism and in the biotechnological production of itaconic acid by Aspergillus terreus We have elucidated the crystal structures of human and murine CADs and compared their enzymological properties to CAD from A. terreus Recombinant CAD is fully active in vitro without a cofactor. Murine CAD has the highest catalytic activity, whereas Aspergillus CAD is best adapted to a more acidic pH. CAD is not homologous to any known decarboxylase and appears to have evolved from prokaryotic enzymes that bind negatively charged substrates. CADs are homodimers, the active center is located in the interface between 2 distinct subdomains, and structural modeling revealed conservation in zebrafish and Aspergillus We identified 8 active-site residues critical for CAD function and rare naturally occurring human mutations in the active site that abolished CAD activity, as well as a variant (Asn152Ser) that increased CAD activity and is common (allele frequency 20%) in African ethnicity. These results open the way for 1) assessing the potential impact of human CAD variants on disease risk at the population level, 2) developing therapeutic interventions to modify CAD activity, and 3) improving CAD efficiency for biotechnological production of itaconic acid.
    • Decreased plasma phospholipid concentrations and increased acid sphingomyelinase activity are accurate biomarkers for community-acquired pneumonia.

      Arshad, Haroon; Alfonso, Juan Carlos López; Franke, Raimo; Michaelis, Katina; Araujo, Leonardo; Habib, Aamna; Zboromyrska, Yuliya; Lücke, Eva; Strungaru, Emilia; Akmatov, Manas K; et al. (Wiley, 2019-11-11)
      BACKGROUND: There continues to be a great need for better biomarkers and host-directed treatment targets for community-acquired pneumonia (CAP). Alterations in phospholipid metabolism may constitute a source of small molecule biomarkers for acute infections including CAP. Evidence from animal models of pulmonary infections and sepsis suggests that inhibiting acid sphingomyelinase (which releases ceramides from sphingomyelins) may reduce end-organ damage. METHODS: We measured concentrations of 105 phospholipids, 40 acylcarnitines, and 4 ceramides, as well as acid sphingomyelinase activity, in plasma from patients with CAP (n = 29, sampled on admission and 4 subsequent time points), chronic obstructive pulmonary disease exacerbation with infection (COPD, n = 13) as a clinically important disease control, and 33 age- and sex-matched controls. RESULTS: Phospholipid concentrations were greatly decreased in CAP and normalized along clinical improvement. Greatest changes were seen in phosphatidylcholines, followed by lysophosphatidylcholines, sphingomyelins and ceramides (three of which were upregulated), and were least in acylcarnitines. Changes in COPD were less pronounced, but also differed qualitatively, e.g. by increases in selected sphingomyelins. We identified highly accurate biomarkers for CAP (AUC ≤ 0.97) and COPD (AUC ≤ 0.93) vs. Controls, and moderately accurate biomarkers for CAP vs. COPD (AUC ≤ 0.83), all of which were phospholipids. Phosphatidylcholines, lysophosphatidylcholines, and sphingomyelins were also markedly decreased in S. aureus-infected human A549 and differentiated THP1 cells. Correlations with C-reactive protein and procalcitonin were predominantly negative but only of mild-to-moderate extent, suggesting that these markers reflect more than merely inflammation. Consistent with the increased ceramide concentrations, increased acid sphingomyelinase activity accurately distinguished CAP (fold change = 2.8, AUC = 0.94) and COPD (1.75, 0.88) from Controls and normalized with clinical resolution. CONCLUSIONS: The results underscore the high potential of plasma phospholipids as biomarkers for CAP, begin to reveal differences in lipid dysregulation between CAP and infection-associated COPD exacerbation, and suggest that the decreases in plasma concentrations are at least partially determined by changes in host target cells. Furthermore, they provide validation in clinical blood samples of acid sphingomyelinase as a potential treatment target to improve clinical outcome of CAP
    • Determination of nasal and oropharyngeal microbiomes in a multicenter population-based study - findings from Pretest 1 of the German National Cohort.

      Akmatov, Manas K; Koch, Nadine; Vital, Marius; Ahrens, Wolfgang; Flesch-Janys, Dieter; Fricke, Julia; Gatzemeier, Anja; Greiser, Halina; Günther, Kathrin; Illig, Thomas; et al. (2017-05-12)
      We examined acceptability, preference and feasibility of collecting nasal and oropharyngeal swabs, followed by microbiome analysis, in a population-based study with 524 participants. Anterior nasal and oropharyngeal swabs were collected by certified personnel. In addition, participants self-collected nasal swabs at home four weeks later. Four swab types were compared regarding (1) participants' satisfaction and acceptance and (2) detection of microbial community structures based on deep sequencing of the 16 S rRNA gene V1-V2 variable regions. All swabbing methods were highly accepted. Microbial community structure analysis revealed 846 phylotypes, 46 of which were unique to oropharynx and 164 unique to nares. The calcium alginate tipped swab was found unsuitable for microbiome determinations. Among the remaining three swab types, there were no differences in oropharyngeal microbiomes detected and only marginal differences in nasal microbiomes. Microbial community structures did not differ between staff-collected and self-collected nasal swabs. These results suggest (1) that nasal and oropharyngeal swabbing are highly feasible methods for human population-based studies that include the characterization of microbial community structures in these important ecological niches, and (2) that self-collection of nasal swabs at home can be used to reduce cost and resources needed, particularly when serial measurements are to be taken.
    • Development of a Bead-Based Multiplex Assay for the Analysis of the Serological Response against the Six Pathogens HAV, HBV, HCV, CMV, T. gondii, and H. pylori.

      Filomena, Angela; Pessler, Frank; Akmatov, Manas K; Krause, Gérard; Duffy, Darragh; Gärtner, Barbara; Gerhard, Markus; Albert, Matthew L; Joos, Thomas O; Schneiderhan-Marra, Nicole; et al. (2017-10-30)
      The spread of infectious diseases and vaccination history are common subjects of epidemiological and immunological research studies. Multiplexed serological assays are useful tools for assessing both current and previous infections as well as vaccination efficacy. We developed a serological multi-pathogen assay for hepatitis A, B and C virus, cytomegalovirus (CMV),
    • Differentiation of Human Pluripotent Stem Cells into Functional Endothelial Cells in Scalable Suspension Culture.

      Olmer, Ruth; Engels, Lena; Usman, Abdulai; Menke, Sandra; Malik, Muhammad Nasir Hayat; Pessler, Frank; Göhring, Gudrun; Bornhorst, Dorothee; Bolten, Svenja; Abdelilah-Seyfried, Salim; et al. (2018-05-08)
      Endothelial cells (ECs) are involved in a variety of cellular responses. As multifunctional components of vascular structures, endothelial (progenitor) cells have been utilized in cellular therapies and are required as an important cellular component of engineered tissue constructs and in vitro disease models. Although primary ECs from different sources are readily isolated and expanded, cell quantity and quality in terms of functionality and karyotype stability is limited. ECs derived from human induced pluripotent stem cells (hiPSCs) represent an alternative and potentially superior cell source, but traditional culture approaches and 2D differentiation protocols hardly allow for production of large cell numbers. Aiming at the production of ECs, we have developed a robust approach for efficient endothelial differentiation of hiPSCs in scalable suspension culture. The established protocol results in relevant numbers of ECs for regenerative approaches and industrial applications that show in vitro proliferation capacity and a high degree of chromosomal stability.
    • Discovery of Leptospira spp. seroreactive peptides using ORFeome phage display.

      Ramli, Siti Roszilawati; Moreira, Gustavo M S G; Zantow, Jonas; Goris, Marga G A; Nguyen, Van Kinh; Novoselova, Natalia; Pessler, Frank; Hust, Michael; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (PLOS, 2019-01-01)
      Leptospirosis is the most common zoonotic disease worldwide. The diagnostic performance of a serological test for human leptospirosis is mainly influenced by the antigen used in the test assay. An ideal serological test should cover all serovars of pathogenic leptospires with high sensitivity and specificity and use reagents that are relatively inexpensive to produce and can be used in tropical climates. Peptide-based tests fulfil at least the latter two requirements, and ORFeome phage display has been successfully used to identify immunogenic peptides from other pathogens. Two ORFeome phage display libraries of the entire Leptospira spp. genomes from five local strains isolated in Malaysia and seven WHO reference strains were constructed. Subsequently, 18 unique Leptospira peptides were identified in a screen using a pool of sera from patients with acute leptospirosis. Five of these were validated by titration ELISA using different pools of patient or control sera. The diagnostic performance of these five peptides was then assessed against 16 individual sera from patients with acute leptospirosis and 16 healthy donors and was compared to that of two recombinant reference proteins from L. interrogans. This analysis revealed two peptides (SIR16-D1 and SIR16-H1) from the local isolates with good accuracy for the detection of acute leptospirosis (area under the ROC curve: 0.86 and 0.78, respectively; sensitivity: 0.88 and 0.94; specificity: 0.81 and 0.69), which was close to that of the reference proteins LipL32 and Loa22 (area under the ROC curve: 0.91 and 0.80; sensitivity: 0.94 and 0.81; specificity: 0.75 and 0.75). This analysis lends further support for using ORFeome phage display to identify pathogen-associated immunogenic peptides, and it suggests that this technique holds promise for the development of peptide-based diagnostics for leptospirosis and, possibly, of vaccines against this pathogen.
    • Early Lymphocyte Loss and Increased Granulocyte/Lymphocyte Ratio Predict Systemic Spread of in a Mouse Model of Acute Skin Infection.

      Loof, Torsten G; Sohail, Aaqib; Bahgat, Mahmoud M; Tallam, Aravind; Arshad, Haroon; Akmatov, Manas K; Pils, Marina C; Heise, Ulrike; Beineke, Andreas; Pessler, Frank; et al.
      Group A streptococci may induce lymphopenia, but the value of lymphocyte loss as early biomarkers for systemic spread and severe infection has not been examined systematically. We evaluated peripheral blood cell indices as biomarkers for severity and spread of infection in a mouse model of skin infection, using two isolates of greatly differing virulence. Internal organs were examined histologically. After subcutaneous inoculation, strain AP1 disseminated rapidly to peripheral blood and internal organs, causing frank sepsis. In contrast, seeding of internal organs by 5448 was mild, this strain could not be isolated from blood, and infection remained mostly localized to skin. Histopathologic examination of liver revealed microvesicular fatty change (steatosis) in AP1 infection, and examination of spleen showed elevated apoptosis and blurring of the white pulp/red pulp border late (40 h post infection) in AP1 infection. Both strains caused profound lymphopenia, but lymphocyte loss was more rapid early in AP1 infection, and lymphocyte count at 6 h post infection was the most accurate early marker for AP1 infection (area under the receiver operator curve [AUC] = 0.93), followed by the granulocyte/lymphocyte ratio (AUC = 0.89). The results suggest that virulence of correlates with the degree of early lymphopenia and underscore the value of peripheral blood indices to predict severity of bacterial infections in mice. Early lymphopenia and elevated granulocyte/lymphocyte ratio merit further investigation as biomarkers for systemic spread of skin infections in humans and, possibly, related pyogenic streptococci in humans and animals.
    • An Egyptian HPAI H5N1 isolate from clade 2.2.1.2 is highly pathogenic in an experimentally infected domestic duck breed (Sudani duck).

      Samir, M; Hamed, M; Abdallah, F; Kinh Nguyen, V; Hernandez-Vargas, E A; Seehusen, F; Baumgärtner, W; Hussein, A; Ali, A A H; Pessler,, F; et al. (2018-01-24)
      The highly pathogenic avian influenza (HPAI) H5N1 viruses continue to cause major problems in poultry and can, although rarely, cause human infection. Being enzootic in domestic poultry, Egyptian isolates are continuously evolving, and novel clades vary in their pathogenicity in avian hosts. Considering the importance of domestic ducks as natural hosts of HPAI H5N1 viruses and their likelihood of physical contact with other avian hosts and humans, it is of utmost importance to characterize the pathogenicity of newly emerged HPAI strains in the domestic duck. The most recently identified Egyptian clade 2.2.1.2 HPAI H5N1 viruses have been isolated from naturally infected pigeons, turkeys and humans. However, essentially nothing is known about their pathogenicity in domestic ducks. We therefore characterized the pathogenicity of an Egyptian HPAI H5N1 isolate A/chicken/Faquos/amn12/2011 (clade 2.2.1.2) in Sudani duck, a domestic duck breed commonly reared in Egypt. While viral transcription (HA mRNA) was highest in lung, heart and kidney peaking between 40 and 48 hpi, lower levels were detected in brain. Weight loss of infected ducks started at 16 hpi and persisted until 120 hpi. The first severe clinical signs were noted by 32 hpi and peaked in severity at 72 and 96 hpi. Haematological analyses showed a decline in total leucocytes, granulocytes, platelets and granulocyte/lymphocyte ratio, but lymphocytosis. Upon necropsy, lesions were obvious in heart, liver, spleen and pancreas and consisted mainly of necrosis and petechial haemorrhage. Histologically, lungs were the most severely affected organs, whereas brain only showed mild neuronal degeneration and gliosis at 48 hpi despite obvious neurological clinical signs. Taken together, our results provide first evidence that this HPAI H5N1 isolate (clade 2.2.1.2) is highly pathogenic to Sudani ducks and highlight the importance of this breed as potential reservoir and disseminator of HPAI strains from this clade.
    • Electro-Microbiology as a Promising Approach Towards Renewable Energy and Environmental Sustainability

      Ali, Jafar; Sohail, Aaqib; Wang, Lei; Rizwan Haider, Muhammad; Mulk, Shahi; Pan, Gang; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (MDPI AG, 2018-07-12)
      Microbial electrochemical technologies provide sustainable wastewater treatment and energy production. Despite significant improvements in the power output of microbial fuel cells (MFCs), this technology is still far from practical applications. Extracting electrical energy and harvesting valuable products by electroactive bacteria (EAB) in bioelectrochemical systems (BESs) has emerged as an innovative approach to address energy and environmental challenges. Thus, maximizing power output and resource recovery is highly desirable for sustainable systems. Insights into the electrode-microbe interactions may help to optimize the performance of BESs for envisioned applications, and further validation by bioelectrochemical techniques is a prerequisite to completely understand the electro-microbiology. This review summarizes various extracellular electron transfer mechanisms involved in BESs. The significant role of characterization techniques in the advancement of the electro-microbiology field is discussed. Finally, diverse applications of BESs, such as resource recovery, and contributions to the pursuit of a more sustainable society are also highlighted.
    • Elevated Free Phosphatidylcholine Levels in Cerebrospinal Fluid Distinguish Bacterial from Viral CNS Infections.

      Al-Mekhlafi, Amani; Sühs, Kurt-Wolfram; Schuchardt, Sven; Kuhn, Maike; Müller-Vahl, Kirsten; Trebst, Corinna; Skripuletz, Thomas; Klawonn, Frank; Stangel, Martin; Pessler, Frank; et al. (MDPI, 2021-05-06)
      The identification of CSF biomarkers for bacterial meningitis can potentially improve diagnosis and understanding of pathogenesis, and the differentiation from viral CNS infections is of particular clinical importance. Considering that substantial changes in CSF metabolites in CNS infections have recently been demonstrated, we compared concentrations of 188 metabolites in CSF samples from patients with bacterial meningitis (n = 32), viral meningitis/encephalitis (n = 34), and noninflamed controls (n = 66). Metabolite reprogramming in bacterial meningitis was greatest among phosphatidylcholines, and concentrations of all 54 phosphatidylcholines were significantly (p = 1.2 × 10-25-1.5 × 10-4) higher than in controls. Indeed, all biomarkers for bacterial meningitis vs. viral meningitis/encephalitis with an AUC ≥ 0.86 (ROC curve analysis) were phosphatidylcholines. Four of the five most accurate (AUC ≥ 0.9) phosphatidylcholine biomarkers had higher sensitivity and negative predictive values than CSF lactate or cell count. Concentrations of the 10 most accurate phosphatidylcholine biomarkers were lower in meningitis due to opportunistic pathogens than in meningitis due to typical meningitis pathogens, and they correlated most strongly with parameters reflecting blood-CSF barrier dysfunction and CSF lactate (r = 0.73-0.82), less so with CSF cell count, and not with blood CRP. In contrast to the elevated phosphatidylcholine concentrations in CSF, serum concentrations remained relatively unchanged. Taken together, these results suggest that increased free CSF phosphatidylcholines are sensitive biomarkers for bacterial meningitis and do not merely reflect inflammation but are associated with local disease and a shift in CNS metabolism.
    • Establishment, Validation, and Initial Application of a Sensitive LC-MS/MS Assay for Quantification of the Naturally Occurring Isomers Itaconate, Mesaconate, and Citraconate.

      Winterhoff, Moritz; Chen, Fangfang; Sahini, Nishika; Ebensen, Thomas; Kuhn, Maike; Kaever, Volkhard; Bähre, Heike; Pessler, Frank; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (MDPI, 2021-04-26)
      Itaconate is derived from the tricarboxylic acid (TCA) cycle intermediate cis-aconitate and links innate immunity and metabolism. Its synthesis is altered in inflammation-related disorders and it therefore has potential as clinical biomarker. Mesaconate and citraconate are naturally occurring isomers of itaconate that have been linked to metabolic disorders, but their functional relationships with itaconate are unknown. We aimed to establish a sensitive high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) assay for the quantification of itaconate, mesaconate, citraconate, the pro-drug 4-octyl-itaconate, and selected TCA intermediates. The assay was validated for itaconate, mesaconate, and citraconate for intra- and interday precision and accuracy, extended stability, recovery, freeze/thaw cycles, and carry-over. The lower limit of quantification was 0.098 µM for itaconate and mesaconate and 0.049 µM for citraconate in 50 µL samples. In spike-in experiments, itaconate remained stable in human plasma and whole blood for 24 and 8 h, respectively, whereas spiked-in citraconate and mesaconate concentrations changed during incubation. The type of anticoagulant in blood collection tubes affected measured levels of selected TCA intermediates. Human plasma may contain citraconate (0.4-0.6 µM, depending on the donor), but not itaconate or mesaconate, and lipopolysaccharide stimulation of whole blood induced only itaconate. Concentrations of the three isomers differed greatly among mouse organs: Itaconate and citraconate were most abundant in lymph nodes, mesaconate in kidneys, and only citraconate occurred in brain. This assay should prove useful to quantify itaconate isomers in biomarker and pharmacokinetic studies, while providing internal controls for their effects on metabolism by allowing quantification of TCA intermediates.
    • Exhaled breath analysis in childhood rheumatic disorders--a longitudinal study.

      Hendel, N; Akmatov, M K; Hamel, J; Vogelberg, C; Pessler, F; TWINCORE Centre for Experimental and Clinical Infection Research Feodor-Lynen-Str. 7 30625 Hannover, Germany. (2016-06)
      We aimed to evaluate the fraction of exhaled nitric oxide (FENO50) and deaerated exhaled breath condensate pH (dEBCpH) as non-invasive markers of subclinical airway inflammation in pediatric patients with rheumatologic disorders. We determined FENO50 and dEBCpH in a prospective study spanning at least 12 months, comprising 85 pediatric patients with rheumatologic disorders, including juvenile idiopathic arthritis (JIA, n  =  63), chronic recurrent multifocal osteomyelitis (CRMO, n  =  6), systemic lupus erythematosus (SLE, n  =  3), juvenile dermatomyositis (JDM, n  =  1) and other rheumatic disorders (n  =  12). dEBCpH was determined once in a group of children without evidence of rheumatologic or pulmonary disease (controls, n  =  90). Findings were correlated with results of pulmonary function tests. Atopic sensitization was assessed by RAST or skin prick test in 76 patients. Atopic sensitization was detected in 34% (26/76) of patients. Neither FENO50 nor dEBCpH correlated with disease activity, but intermediately (20-35 ppb) or highly elevated (>35 ppb) levels were observed at least once in 26 patients (31%), 19 of whom had atopic sensitization. Median dEBCpH did not differ between cases and controls (8.05 versus 8.02; p  =  0.48). Median dEBCpH decreased slightly over the study period (p  =  0.02), whereas FENO50 values did not change significantly (p  =  0.89). There were several patients with significantly abnormal dEBCpH values that could not be readily explained by diagnosis, higher disease activity, medications, or atopic sensitization. Thus, there were no consistent abnormalities in FENO50 or dEBCpH in this cohort of Caucasian patients with relatively stable rheumatologic disorders, but there were some patients with abnormal values of unknown significance.
    • Gene Regulatory Network Inference of Immunoresponsive Gene 1 (IRG1) Identifies Interferon Regulatory Factor 1 (IRF1) as Its Transcriptional Regulator in Mammalian Macrophages.

      Tallam, Aravind; Perumal, Thaneer M; Antony, Paul M; Jäger, Christian; Fritz, Joëlle V; Vallar, Laurent; Balling, Rudi; Del Sol, Antonio; Michelucci, Alessandro; Twincore Centre of Experimental and Clinical Infection Research; a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover 30625, Germany. (2016)
      Immunoresponsive gene 1 (IRG1) is one of the highest induced genes in macrophages under pro-inflammatory conditions. Its function has been recently described: it codes for immune-responsive gene 1 protein/cis-aconitic acid decarboxylase (IRG1/CAD), an enzyme catalysing the production of itaconic acid from cis-aconitic acid, a tricarboxylic acid (TCA) cycle intermediate. Itaconic acid possesses specific antimicrobial properties inhibiting isocitrate lyase, the first enzyme of the glyoxylate shunt, an anaplerotic pathway that bypasses the TCA cycle and enables bacteria to survive on limited carbon conditions. To elucidate the mechanisms underlying itaconic acid production through IRG1 induction in macrophages, we examined the transcriptional regulation of IRG1. To this end, we studied IRG1 expression in human immune cells under different inflammatory stimuli, such as TNFα and IFNγ, in addition to lipopolysaccharides. Under these conditions, as previously shown in mouse macrophages, IRG1/CAD accumulates in mitochondria. Furthermore, using literature information and transcription factor prediction models, we re-constructed raw gene regulatory networks (GRNs) for IRG1 in mouse and human macrophages. We further implemented a contextualization algorithm that relies on genome-wide gene expression data to infer putative cell type-specific gene regulatory interactions in mouse and human macrophages, which allowed us to predict potential transcriptional regulators of IRG1. Among the computationally identified regulators, siRNA-mediated gene silencing of interferon regulatory factor 1 (IRF1) in macrophages significantly decreased the expression of IRG1/CAD at the gene and protein level, which correlated with a reduced production of itaconic acid. Using a synergistic approach of both computational and experimental methods, we here shed more light on the transcriptional machinery of IRG1 expression and could pave the way to therapeutic approaches targeting itaconic acid levels.