Thilo Welsch

Recalling superior mesenteric artery syndrome.

Background: Superior mesenteric artery syndrome is uncommon and characterized by postprandial epigastric pain, nausea, vomiting, anorexia and weight loss. The syndrome is caused by compression of the third part of the duodenum in the angle between the aorta and the superior mesenteric artery. This review updates etiology, epidemiology, diagnosis, treatment and outcome of the superior mesenteric artery syndrome. Methods: Review of the literature. Results: Frequently, predisposing medical conditions associated with catabolic states or rapid weight loss result in a decrease of the aortomesenteric angle and subsequent duodenal obstruction. External cast compression, anatomic variants and surgical alteration of the anatomy following spine surgery or ileoanal pouch anastomosis can also precipitate the syndrome. Once radiologic studies have established diagnosis, first-line treatment is usually conservative with jejunal or parenteral nutrition for restoration of the aortomesenteric fatty tissue. If conservative management fails, surgical options include open or laparoscopic duodenojejunostomy or duodenal mobilization and division of the ligament of Treitz. Conclusion: Superior mesenteric artery syndrome is clearly defined and frequently associated with a wide range of predisposing conditions and surgical procedures; clinicians have to consider this syndrome in such a setting. Larger studies are needed to better define the optimal treatment for this disease.

Molecular pathogenesis of pancreatic cancer: advances and challenges.

Pancreatic ductal adenocarcinoma (PDAC) is still a devastating and incurable disease with a median survival of 3-6 months and a 5-year survival rate of 1-4% when all stages are considered. Although crucial advances in our understanding of the molecular pathogenesis of the disease have been made, the exceptional aggressiveness of PDAC remains largely unexplained. Some key results will probably direct future PDAC research activities. For example, recent identification of pancreatic tumor stem cells has stimulated the debate over the cell of origin. Further, powerful new genetically engineered mouse models support the concept that stepwise progression of epithelial precursor lesions leads to invasive PDAC as a result of accumulating mutations in K-ras, INK4A/ARF, TP53 and DPC4; these models accentuate the initiating function of the K-ras mutation. Established PDAC exhibits all the classic hallmarks of cancer, including self-sufficiency in growth signals, insensitivity to anti-growth signals, evasion of apoptosis, limitless replicative potential, sustained angiogenesis, tissue invasion, and metastasis. This review provides an overview of the molecular machinery that PDAC utilizes to acquire these tumorigenic capacities. Moreover, recent advances have identified essential elements of key pathways partly recapitulating developmental signals, and of the tumor microenvironment that promotes tumor growth through the complex interplay of its different cellular components. In spite of progress in molecular research, there is still a dichotomy between the encouraging results obtained with targeted interference of numerous oncogenic pathways in vitro and a lack of significant improvement in clinical detection and survival. Thus our primary challenge remains to translate the solid knowledge of genetic and epigenetic alterations in PDAC into clinical tools which can be used for early diagnosis and effective therapy.

Low expression of aldehyde deyhdrogenase 1A1 (ALDH1A1) is a prognostic marker for poor survival in pancreatic cancer

BackgroundAldehyde deyhdrogenase 1 (ALDH1) has been characterised as a cancer stem cell marker in different types of tumours. Additionally, it plays a pivotal role in gene regulation and endows tumour cells with augmented chemoresistance. Recently, ALDH1A1 has been described as a prognostic marker in a pancreatic cancer tissue microarray. The aim of this study was to reevaluate the expression of ALDH1A1 as a prognostic marker on whole-mount tissue sections.MethodsReal-time-quantitative-PCR (qRT-PCR) and Western blotting were used to evaluate the expression profile of ALDH1A1 in seven pancreatic cancer cell lines and one non-malignant pancreatic cell line. Immunostaining against ALDH1A1 and Ki-67 was performed on paraffin-embedded samples from 97 patients with pancreatic cancer. The immunohistochemical results were correlated to histopathological and clinical data.ResultsqRT-PCR and Western blotting revealed a different expression pattern of ALDH1A1 in different malignant and non-malignant pancreatic cell lines. Immunohistochemical analysis demonstrated that ALDH1A1 was confined to the cellular cytoplasm and occurred in 72 cases (74%), whereas it was negative in 25 cases (26%). High expression of ALDH1A1 was significantly correlated to an increased proliferation rate (Spearman correlation, p = 0.01). Univariate and multivariate analyses showed that decreased expression of ALDH1A1 is an independent adverse prognostic factor for overall survival.ConclusionsImmunonhistochemical analysis on whole-mount tissue slides revealed that ALDH1A1 is more abundantly expressed in pancreatic cancer than initially reported by a tissue microarray analysis. Moreover, high expression of ALDH1A1 correlated significantly with the proliferation of tumour cells. Intriguingly, this study is the first which identifies low expression of ALDH1A1 as an independent adverse prognostic marker for overall survival in pancreatic cancer.

EAES recommendations on methodology of innovation management in endoscopic surgery

BackgroundUnder the mandate of the European Association for Endoscopic Surgery (EAES) a guideline on methodology of innovation management in endoscopic surgery has been developed. The primary focus of this guideline is patient safety, efficacy, and effectiveness.MethodsAn international expert panel was invited to develop recommendations for the assessment and introduction of surgical innovations. A consensus development conference (CDC) took place in May 2009 using the method of a nominal group process (NGP). The recommendations were presented at the annual EAES congress in Prague, Czech Republic, on June 18th, 2009 for discussion and further input. After further Delphi processes between the experts, the final recommendations were agreed upon.ResultsThe development and implementation of innovations in surgery are addressed in five sections: (1) definition of an innovation, (2) preclinical and (3) clinical scientific development, (4) scientific approval, and (5) implementation along with monitoring. Within the present guideline each of the sections and several steps are defined, and several recommendations based on available evidence have been agreed within each category. A comprehensive workflow of the different steps is given in an algorithm. In addition, issues of health technology assessment (HTA) serving to estimate efficiency followed by ethical directives are given.ConclusionsInnovations into clinical practice should be introduced with the highest possible grade of safety for the patient (nil nocere: do no harm). The recommendations can contribute to the attainment of this objective without preventing future promising diagnostic and therapeutic innovations in the field of surgery and allied techniques.

Validation of the International Study Group of Rectal Cancer definition and severity grading of anastomotic leakage.

BACKGROUND The International Study Group of Rectal Cancer (ISREC) has proposed a generally applicable definition and severity grading of (AL) after sphincter-preserving resection of the rectum. This work has been carried out to test for validity. METHODS A total of 746 patients who were identified from a prospective rectal cancer database underwent sphincter-preserving anterior resection of the rectum between October 2001 and January 2011. The incidence and severity of AL was determined using the criteria established by the ISREC. Patients with AL were categorized according to the ISREC scheme. The clinical outcomes were analyzed and compared between the groups. RESULTS The overall AL rate was 7.5% (56/746). The 56 patients with AL were distributed among the different groups as follows: Grade A, 16%; grade B, 23%; and grade C, 61%. Compared with the grade A patients, grades B and C patients had significantly elevated serum C-reactive protein levels (P < .01). None of the grade A patients were transferred to the intensive care unit (ICU). Their further hospital stay was uneventful. The length of stay in the ICU was significantly longer for grade C patients compared with grade B patients (P < .001). The median hospital stay of grade C patients was significantly longer than that of grades A and B patients (P < .001). CONCLUSION The definition and severity grading of AL after anterior resection of the rectum proposed by the ISREC provides a simple, easily applicable, and valid classification. Using this classification system may facilitate comparison of results from different studies on AL after sphincter-preserving rectal surgery.

Palladin is a dynamic actin-associated protein in podocytes

Palladin, a cytoskeletal protein with essential functions for stress fiber formation, is found in developing and mature tissues, including the kidney. To define its role in the kidney, we measured its expression in mouse kidney and found it co-localized with F-actin in smooth muscle cells of renal arterial vessels, mesangial cells, and podocytes but not in tubular epithelium. Using immunoelectron microscopy, we confirmed that palladin was present in podocytes. In cultured mouse podocytes, palladin co-localized with F-actin in dense regions of stress fibers, focal adhesions, cell-cell contacts and motile cell margins. Transfection with the N-terminal half of palladin targeted it to F-actin-containing structures in podocytes while the C-terminal half accumulated in the nucleus, a result also found for endogenous palladin in cultured cells after leptomycin B was used to block nuclear export. Green fluorescent protein (GFP)-tagged palladin was found in dynamic ring-like F-actin structures and ruffles in cultured podocytes after stimulation with epidermal growth factor. Inhibition of palladin expression by transfection of an antisense construct reduced the formation of ring-like structures. Photo-bleaching analysis showed that GFP-palladin turned over with a half-time of 10 s in focal adhesions and dense regions of stress fibers, suggesting that palladin is a dynamic scaffolding protein. Our study shows that palladin is expressed in podocytes and plays an important role in actin dynamics.

Actinin-4 expression in primary and metastasized pancreatic ductal adenocarcinoma.

Objectives: Actinin-4 is an actin-bundling protein that probably has a tumor-promoting potential in several solid tumors. The present study analyzed the expression of actinin-4 in the pancreas, in localized and metastasized pancreatic ductal adenocarcinoma (PDAC), and the correlation with clinical outcome. Methods: Pancreatic ductal adenocarcinoma tissue from 38 patients, 15 lymph node and 10 liver metastases, normal pancreas, and 4 PDAC cell lines, were examined by immunohistochemistry, and actinin-4 expression was quantified by immunofluorescence analysis. Results: In the normal pancreas, actinin-4 was most prominently expressed in ductal cells. In PDAC, tumor cells exhibited strong but differential cytoplasmic immunoreactivity for actinin-4. A multivariate analysis revealed actinin-4 immunoreactivity, advanced age, and undifferentiated grade as significant prognostic factors associated with worse survival after PDAC resection. Cells metastasized to lymph nodes or to the liver exhibited no significant increase of actinin-4 compared with the primary tumors. A nuclear staining was observed neither in any of the PDAC samples nor in the 4 cell lines. In PDAC cells, actinin-4 localized to dynamic actin structures and to invadopodia. Conclusions: Actinin-4 expression levels significantly correlate with worse survival after PDAC resection. Although actinin-4 has been reported to promote lymph node metastases, there was no enhanced expression in PDAC metastases.

Autoimmune Pancreatocholangitis, Non-Autoimmune Pancreatitis and Primary Sclerosing Cholangitis: A Comparative Morphological and Immunological Analysis

Background Autoimmune pancreatocholangitis (AIPC) is an emerging, not completely characterized disease. Aim of this study was the comprehensive evaluation of a series of AIPC patients, who were diagnosed and treated in a European institution between January 2003 and July 2006. Methodology/Principal Findings Thirty-three patients with histologically confirmed AIPC were analyzed and compared to 20 patients with non-autoimmune chronic pancreatitis (CP) and 14 patients with primary sclerosing cholangitis (PSC). Clinical features and conventional histopathology were taken into account. Immunohistochemistry and real-time quantitative PCR were used for the characterization of the inflammatory infiltrate and the stromal reaction. AIPC was localized in the pancreatic head in 94% of the patients. Intra- and/or extrapancreatic biliary tract involvement was present in 64% of the cases. The number of infiltrating T-lymphocytes, macrophages and total plasma cells was significantly higher in AIPC than in CP (3-, 4- and 8-fold increase, respectively). The absolute number of IgG4-positive plasma cells was higher in AIPC than in CP and PSC (7-fold and 35-fold increase, respectively), but significance was only reached in comparison with PSC. CXCR5- and CXCL13-positive cells were almost exclusively detected in AIPC. Conclusions/Significance AIPC is mainly a disease of the pancreatic head with possible extension into the periphery of the gland and/or into the biliary tract/gallbladder. The morphology of AIPC, as well as the immune- and stromal reaction is characteristic and comparable between cases with and without biliary tract involvement. Immunological markers (IgG4, CXCR5, CXCL13) can be of diagnostic relevance in specific settings.

Update on pancreatic cancer and alcohol-associated risk

Ductal adenocarcinoma of the pancreas is characterized by extremely aggressive behavior, with an overall 5‐year survival of <4%. Because conventional and specifically tailored therapeutic regimens have little impact on patient survival, epidemiological and molecular research aims at identifying and reducing risk factors. Cigarette smoking, obesity, diabetes mellitus, and chronic pancreatitis are amenable to medical prevention or therapy. Heavy alcohol consumption is an inconsistent single risk factor for pancreatic cancer but may promote carcinogenesis by increasing the risk of diabetes mellitus or chronic pancreatitis. For various agents, the key carcinogenic effect is probably an inflammatory response in the pancreatic tissue. On the molecular level, mutations of oncogenes and tumor suppressor genes, as well as various epigenetic alterations, such as overexpression of growth factors and their receptors, are important in tumorigenesis. Complete and safe surgical resection, together with adjuvant therapy, offers prolonged survival, with 5‐year survival rates of approximately 25%. However, for unresectable or disseminated disease, which constitutes the vast majority of cases, treatment is palliative. Despite increasing knowledge about the molecular pathology of pancreatic cancer and despite advances in treatment, the overall course of the disease is dismal, and reinforced efforts to reduce incidence and improve outcome are needed desperately.

Elevated L1CAM expression in precursor lesions and primary and metastastic tissues of pancreatic ductal adenocarcinoma.

The promigratory molecule L1CAM is overexpressed in various tumors, often representing an unfavorable prognostic marker. Recently, we identified L1CAM expression in pancreatic ductal adenocarcinoma (PDAC) cells accounting for chemoresistance and increased cell migration. Thus, the present study aims at further elucidating the role of L1CAM in a larger cohort of PDAC specimens including precursor lesions and metastasis. L1CAM expression was determined by immunohistochemistry in tissues of 123 patients including tissues of 110 primary PDACs, 15 lymph node metastases and 14 liver metastases. The immunohistochemical analyses revealed L1CAM expression in 92.7% of primary PDACs, 80% of lymph node metastases and 100% of liver metastases. Furthermore, we have investigated PDAC precursors, pancreatic intraepithelial neoplasia (PanIN) lesions, revealing a significant increase of L1CAM expression with the PanIN grade (6.4 and 6.8% in PanIN 1A and B, 35% in PanIN 2 and 20% in PanIN 3). The elevated expression of L1CAM already found in PanINs points to a role of L1CAM quite early in tumorigenesis of PDAC. Furthermore, its broad expression in primary tumors as well as in metastases of PDAC patients provide a rationale to further explore the value of L1CAM as a therapeutic target in the treatment of this highly malignant tumor.