Untersuchungen zu neuen diagnostischen und prognostischen Biomarkern bei Patienten mit entzündlichen und onkologischen Erkrankungen des gastrointestinalen Traktes

Für die chronisch entzündlichen Darmerkrankungen (CED) als auch für das kolorektale Karzinom (KRK) existieren wenige etablierte Biomarker mit Relevanz für Diagnose, Prognose oder Therapieansprechen. Bislang fehlt es an Biomarkern, die die Progression einer CED zu einem KRK sicher abbilden. Die Identifizierung von neuen krankheitsspezifischen Biomarkern könnte daher zum besseren pathomechanistischen Verständnis und zur Behandlungsoptimierung beitragen. So wurde FNDC4 als antiinflammatorischer Faktor beschrieben, der in CED hochreguliert ist. Der G-Protein-gekoppelte Rezeptor 116 (GPR116) wurde als potentieller FNDC4-Rezeptor gefunden. Das erste Ziel dieser Arbeit ist die Analyse der mRNA Expression der FNDC Familie und GPR116 in nicht-affektierten und affektierten Gewebeproben von Patienten mit CED oder KRK. Mukosaproben wurden von 30 Patienten im Rahmen von diagnostischen Koloskopien oder chirurgischen Resektionen von CED und KRK gewonnen. Die Genexpression wurde mittels quantitativer Real-Time PCR bestimmt. FNDC1 und FNDC4 waren in CED, im Vergleich zur nicht-affektierter Mukosa, signifikant hochreguliert. Keine der untersuchten FNDCs wurde im KRK different exprimiert. Die Versuche zur Etablierung einer Proteinfärbung von FNDC4 schlugen, bedingt durch eine fragliche Antikörperspezifität und Autofluoreszenz (AF) des verwendeten Gewebes, fehl. Allerdings konnten charakteristische AF-Musterstrukturen identifiziert werden. AF Signale wurden durch Lipofuszin verursacht und zeigten sich vermehrt in entzündetem Gewebe. Daher kann AF als diagnostischer Biomarker für intestinale Inflammation angesehen werden. In dieser Arbeit wird weiterhin das Wissen zu prognostischen Biomarkern im Blut von chirurgischen Patienten für eine optimale präoperative metabolische Vorbereitung erweitert. Bei Operationen des KRK bestehen bei Patienten oft präoperative Fastenperioden mit reduzierter postoperativer Rekonvaleszenz. An 50 Patienten mit elektiven Operationen am unteren und oberen GI-Trakt erfolgte eine Blutanalyse von möglichen Biomarkern im perioperativen Setting. Eine multivariate Regressionsanalyse zeigte Glutaminsäure und Valin als signifikante unabhängige Prädiktoren der präoperativen Fastenzeit. Zusammenfassend könnten FNDC1 und FNDC4 eine relevante Rolle in der Pathobiologie der CED spielen. Autofluoreszenz kann als diagnostischer Biomarker der CEDs angesehen werden, limitiert allerdings spezifische Immunfluoreszenzfärbungen. Im klinischen Kontext kann eine Messung des Aminosäurenprofils einen zeitgerechte Nahrungsunterstützung bei länger fastenden Patienten vor Operationen erlauben.A few common biomarkers exist for inflammatory bowel disease (IBD) and colorectal cancer (CRC) with relevance for diagnosis, prognosis und therapy. The identification of new disease specific biomarkers could reveal a better pathomechanistic understanding, thus optimizing treatment. FNDC4 was described as anti-inflammatory factor, upregulated in IBD. The G-protein-coupled receptor 116 (GPR116) was found to be a putative FNDC4 receptor. This work first aims to analyze the mRNA expression of the FNDC family and GPR116 in nonaffected and affected mucosal samples of patients with IBD or CRC. Mucosa samples were obtained from 30 patients undergoing diagnostic colonoscopy or from surgical resection of IBD or CRC. Gene expression was determined by quantitative real-time PCR. FNDC1 and FNDC4 were significantly upregulated in IBD, compared to unaffected mucosa. None of the investigated FNDCs was differentially expressed in CRC. The attempts to establish protein staining of FNDC4 failed due to questionable antibody specification and autofluorescence (AF) of assessed tissue. Although, specific AF-structures were identified. AF signals were related with lipofuscin accumulation and appeared more pronounced in inflamed tissues. Therefore, AF appeared as a diagnostic biomarker for colonic inflammation. Within this study, it is further sought to advance the knowledge on prognostic biomarkers in the plasma that allow the metabolic characterization of surgical patients for an optimized preoperative metabolic preparation. In CRC surgery, patients often suffer from preoperative fasting periods leading to decelerate recovery after surgery. In 50 patients with elective surgery of the upper and lower gastrointestinal tract blood analysis of potential biomarkers in the perioperative setting was performed. A multivariate regression analysis revealed glutamic acid and valine as significant independent predictors of preoperative fasting periods. Taken together, FNDC1 and FNDC4 may play a relevant role in the pathobiology of IBD. AF is a diagnostic biomarker for IBD, although it limits specific immunofluorescence staining. In clinical context measurement of amino acids profiles allows timely nutritional support for prolong fasted patient before surgery

Recent Advances and the Potential for Clinical Use of Autofluorescence Detection of Extra-Ophthalmic Tissues

The autofluorescence (AF) characteristics of endogenous fluorophores allow the label-free assessment and visualization of cells and tissues of the human body. While AF imaging (AFI) is well-established in ophthalmology, its clinical applications are steadily expanding to other disciplines. This review summarizes clinical advances of AF techniques published during the past decade. A systematic search of the MEDLINE database and Cochrane Library databases was performed to identify clinical AF studies in extra-ophthalmic tissues. In total, 1097 articles were identified, of which 113 from internal medicine, surgery, oral medicine, and dermatology were reviewed. While comparable technological standards exist in diabetology and cardiology, in all other disciplines, comparability between studies is limited due to the number of differing AF techniques and non-standardized imaging and data analysis. Clear evidence was found for skin AF as a surrogate for blood glucose homeostasis or cardiovascular risk grading. In thyroid surgery, foremost, less experienced surgeons may benefit from the AF-guided intraoperative separation of parathyroid from thyroid tissue. There is a growing interest in AF techniques in clinical disciplines, and promising advances have been made during the past decade. However, further research and development are mandatory to overcome the existing limitations and to maximize the clinical benefits

Expression Analysis of Fibronectin Type III Domain-Containing (FNDC) Genes in Inflammatory Bowel Disease and Colorectal Cancer

Background. Fibronectin type III domain-containing (FNDC) proteins fulfill manifold functions in tissue development and regulation of cellular metabolism. FNDC4 was described as anti-inflammatory factor, upregulated in inflammatory bowel disease (IBD). FNDC signaling includes direct cell-cell interaction as well as release of bioactive peptides, like shown for FNDC4 or FNDC5. The G-protein-coupled receptor 116 (GPR116) was found as a putative FNDC4 receptor. We here aim to comprehensively analyze the mRNA expression of FNDC1, FNDC3A, FNDC3B, FNDC4, FNDC5, and GPR116 in nonaffected and affected mucosal samples of patients with IBD or colorectal cancer (CRC). Methods. Mucosa samples were obtained from 30 patients undergoing diagnostic colonoscopy or from surgical resection of IBD or CRC. Gene expression was determined by quantitative real-time PCR. In addition, FNDC expression data from publicly available Gene Expression Omnibus (GEO) data sets (GDS4296, GDS4515, and GDS5232) were analyzed. Results. Basal mucosal expression revealed higher expression of FNDC3A and FNDC5 in the ileum compared to colonic segments. FNDC1 and FNDC4 were significantly upregulated in IBD. None of the investigated FNDCs was differentially expressed in CRC, just FNDC3A trended to be upregulated. The GEO data set analysis revealed significantly downregulated FNDC4 and upregulated GPR116 in microsatellite unstable (MSI) CRCs. The expression of FNDCs and GPR116 was independent of age and sex. Conclusions. FNDC1 and FNDC4 may play a relevant role in the pathobiology of IBD, but none of the investigated FNDCs is regulated in CRC. GPR116 may be upregulated in advanced or MSI CRC. Further studies should validate the altered FNDC expression results on protein levels and examine the corresponding functional consequences