CD44 proteins are cell surface receptors for hyaluronic acid (HA), a component of the extracellular matrix that has multiple effects on cell behavior. CD44 can be shed from the cell surface by proteolytic cleavage. The resulting soluble form can interfere with the interaction between HA and membrane-bound CD44. Soluble CD44 can abolish the cell proliferation-promoting effect of HA on melanoma cell lines, suggesting that a better understanding of the shedding process might identify ways of blocking tumor cell proliferation. ADAM10, ADAM17, and MMP14 have previously been implicated in the shedding of CD44 from various tumor cells. Using immunohistochemistry we demonstrate that ADAM10 and ADAM17 but not MMP14 are significantly expressed on melanoma cells in histological sections. In human melanoma cell lines expression of these proteases could be blocked by transfection with appropriate siRNAs. However, only blocking of ADAM10 expression led to decreased shedding of CD44. In parallel, cell proliferation was promoted. Confocal microscopy demonstrated that ADAM10 and CD44 colocalize on the cell surface. We conclude that ADAM10 is the predominant protease involved in the constitutive shedding of endogenous CD44 from melanoma cells, and that enhancement of ADAM10 activity could be an approach to decrease the proliferation of melanoma cells.

IntroductionThe model for end-stage liver disease (MELD) score is used in many countries to prioritize organ allocation for the majority of patients who require orthotopic liver transplantation. This score is calculated based on the following laboratory parameters: creatinine, bilirubin and the international normalized ratio (INR). Consequently, high measurement accuracy is essential for equitable and fair organ allocation. For serum creatinine measurements, the Jaffé method and enzymatic detection are well-established routine diagnostic tests.MethodsA total of 1,013 samples from 445 patients on the waiting list or in evaluation for liver transplantation were measured using both creatinine methods from November 2012 to September 2013 at the university hospital Leipzig, Germany. The measurements were performed in parallel according to the manufacturer’s instructions after the samples arrived at the institute of laboratory medicine. Patients who had required renal replacement therapy twice in the previous week were excluded from analyses.ResultsDespite the good correlation between the results of both creatinine quantification methods, relevant differences were observed, which led to different MELD scores. The Jaffé measurement led to greater MELD score in 163/1,013 (16.1%) samples with differences of up to 4 points in one patient, whereas differences of up to 2 points were identified in 15/1,013 (1.5%) samples using the enzymatic assay. Overall, 50/152 (32.9%) patients with MELD scores >20 had higher scores when the Jaffé method was used.DiscussionUsing the Jaffé method to measure creatinine levels in samples from patients who require liver transplantation may lead to a systematic preference in organ allocation. In this study, the differences were particularly pronounced in samples with MELD scores >20, which has clinical relevance in the context of urgency of transplantation. These data suggest that official recommendations are needed to determine which laboratory diagnostic methods should be used when calculating MELD scores.

ZusammenfassungDie Weiterbildung in der Klinischen Chemie und Laboratoriumsmedizin ist in Europa heterogen. Mediziner, Naturwissenschaftler und Pharmazeuten können sich in Europa in der Klinischen Chemie und Laboratoriumsmedizin weiterbilden. Die Weiterbildungszeiten und -inhalte sowie Abschlussmodalitäten unterscheiden sich jedoch voneinander. Mit dem Ziel der Harmonisierung und Qualitätssicherung der Weiterbildung in Europa veröffentlichten sowohl die Sektion „Laboratory Medicine/Medical Biopathology“ der „European Union of Medical Specialists“ (UEMS) als auch die „European Federation of Clinical Chemistry and Laboratory Medicine“ (EFLM) 2012 ein überarbeitetes Curriculum für die postgraduale Weiterbildung in der Klinischen Chemie und Laboratoriumsmedizin. Die EFLM führte die Berufsbezeichnung „Specialist in Laboratory Medicine“ (ehemals „European Specialist in Clinical Chemistry and Laboratory Medicine“) ein. Die UEMS vergibt den polyvalenten Titel „Specialist in General Laboratory Medicine – Polyvalent Medical Biopathology“ sowie 4 monovalente Titel. Die vorliegende Arbeit gibt eine Übersicht zum aktuellen Stand der Weiterbildung in der Klinischen Chemie und Laboratoriumsmedizin in den EU-Staaten im Vergleich zu Deutschland. Die Ziele der UEMS und EFLM als Dachorganisationen der Klinischen Chemie und Laboratoriumsmedizin in der EU werden diskutiert.