Promising Metabolite Profiles in the Plasma and CSF of Early Clinical Parkinson's Disease

Parkinson's disease (PD) shows high heterogeneity with regard to the underlying molecular pathogenesis involving multiple pathways and mechanisms. Diagnosis is still challenging and rests entirely on clinical features. Thus, there is an urgent need for robust diagnostic biofluid markers. Untargeted metabolomics allows establishing low-molecular compound biomarkers in a wide range of complex diseases by the measurement of various molecular classes in biofluids such as blood plasma, serum, and cerebrospinal fluid (CSF). Here, we applied untargeted high-resolution mass spectrometry to determine plasma and CSF metabolite profiles. We semiquantitatively determined small-molecule levels (≤1.5 kDa) in the plasma and CSF from early PD patients (disease duration 0-4 years; n = 80 and 40, respectively), and sex- and age-matched controls (n = 76 and 38, respectively). We performed statistical analyses utilizing partial least square and random forest analysis with a 70/30 training and testing split approach, leading to the identification of 20 promising plasma and 14 CSF metabolites. These metabolites differentiated the test set with an AUC of 0.8 (plasma) and 0.9 (CSF). Characteristics of the metabolites indicate perturbations in the glycerophospholipid, sphingolipid, and amino acid metabolism in PD, which underscores the high power of metabolomic approaches. Further studies will enable to develop a potential metabolite-based biomarker panel specific for PD

Critical role of the disintegrin metalloprotease ADAM17 for intestinal inflammation and regeneration in mice

The protease a disintegrin and metalloprotease (ADAM) 17 cleaves tumor necrosis factor (TNF), L-selectin, and epidermal growth factor receptor (EGF-R) ligands from the plasma membrane. ADAM17 is expressed in most tissues and is up-regulated during inflammation and cancer. ADAM17-deficient mice are not viable. Conditional ADAM17 knockout models demonstrated proinflammatory activities of ADAM17 in septic shock via shedding of TNF. We used a novel gene targeting strategy to generate mice with dramatically reduced ADAM17 levels in all tissues. The resulting mice called ADAM17ex/ex were viable, showed compromised shedding of ADAM17 substrates from the cell surface, and developed eye, heart, and skin defects as a consequence of impaired EGF-R signaling caused by failure of shedding of EGF-R ligands. Unexpectedly, although the intestine of unchallenged homozygous ADAM17ex/ex mice was normal, ADAM17ex/ex mice showed substantially increased susceptibility to inflammation in dextran sulfate sodium colitis. This was a result of impaired shedding of EGF-R ligands resulting in failure to phosphorylate STAT3 via the EGF-R and, consequently, in defective regeneration of epithelial cells and breakdown of the intestinal barrier. Besides regulating the systemic availability of the proinflammatory cytokine TNF, our results demonstrate that ADAM17 is needed for vital regenerative activities during the immune response. Thus, our mouse model will help investigate ADAM17 as a potential drug target

Prozeßüberwachung bei der Laseroberflächenbehandlung durch Reflexions- und Temperaturmessung

Das Ziel dieser Arbeit bestand in der Entwicklung und Auslegung einer Sensoreinheit zur Überwachung der umschmelzenden Verfahren der Laseroberflächenbehandlung. Die sensorspezifische Detektion und Auswertung von Prozeßkenngrößen direkt aus der Wechselwirkungszone zwischen Laserstrahl und Werkstückoberfläche soll den Prozeß beschreiben und gibt die Möglichkeit, eine online-Prozeßüberwachung aufzubauen und somit die Sicherheit und Qualität der Oberflächenbehandlung mit Laserstrahlung zu erhöhen

AMPEROMETRIC ENZYME ELECTRODES FOR NAD(P)H AND UREA

Amperometric enzyme electrodes for NAD(P)H as well as bienzyme electrodes for dehydrogenase substrates have been developed on the basis of the horseradish peroxidase catalyzed aerobic oxidation of reduced pyridine nucleotides. Limits of detection are: 20 ymol/l NADH or 30 umol/1 NADPH in the HRP electrode and 0.8 umol/1 NAD(P)H, 80 pmol/l glucose, 100 ywmol/l ethanol and 200 umol/l isocitrate in HRP-dehydrogenase bienzyme electrodes with cofactor recycling. Relative standard deviations are 4 %, measuring frequencies 6-8 samples/h. Other types of amperometric biosensors are based on the electrochenical hydrazine oxidation. The dependence of the anodic current on the hydrazine concentration at constant pH values was used to determine enzyme activities of human serum and bovine eye lens leucine aminopeptidase (LAP) and of human serum alanine aminopeptidase (AAP). Detection limits were 5 units/l, the correlation of the results in serum with the respective optical method was better for AAP then for LAP. Kinetic constants of bovine lens LAP were found in the same range as with the optical method. At constant hydrazine concentration its oxidation current is a linear function of the hydroxyl ion concentration. This dependence was used to develop an amperomeric urea electrode. Typical parameters are: linear range 0.8-35 mmol/l, response time 20s, relative standard deviation 1%, frequency 40 samples/h and operational stability two weeks. The urea content in pure solutions, in dialysates of artificial kidneys and in human serum was determined in good correlation with Berthelot’s method. Buffer influences were eliminated by two electrode difference measurements

Rotigotine is a potent agonist at dopamine D-1 receptors as well as at dopamine D-2 and D-3 receptors

Background and PurposeRotigotine acts as a dopamine receptor agonist with high affinity for the dopamine D-2, D-3, D-4 and D-5 receptors but with a low affinity for the dopamine D-1 receptor. We have investigated this further in radioligand binding and functional studies and compared the profile of rotigotine with that of other drugs used in the treatment of Parkinson's disease (PD). Experimental ApproachThe binding of rotigotine to human dopamine D-1, D-2, D-3, D-4 and D-5 receptors was determined in radioligand binding studies using [H-3]rotigotine and compared with that of standard antagonist radioligands. Functional interactions of rotigotine with human dopamine receptors was also determined. Key Results[H-3]rotigotine can be used as an agonist radioligand to label all dopamine receptor subtypes and this can be important to derive agonist affinity estimates. Rotigotine maintains this high affinity in functional studies at all dopamine receptors especially D-1, D-2 and D-3 receptors and, to a lesser extent, D-4 and D-5 receptors. Rotigotine, like apomorphine but unlike ropinirole and pramipexole, was a potent agonist at all dopamine receptors. Conclusions and ImplicationsRotigotine is a high-potency agonist at human dopamine D-1, D-2 and D-3 receptors with a lower potency at D-4 and D-5 receptors. These studies differentiate rotigotine from conventional dopamine D-2 agonists, used in the treatment of PD, such as ropinirole and pramipexole which lack activity at the D-1 and D-5 receptors, but resembles that of apomorphine which has greater efficacy in PD than other dopamine agonists but has suboptimal pharmacokinetic properties

Unprecedented therapeutic potential with a combination of A2A/NR2B receptor antagonists as observed in the 6-OHDA lesioned rat model of Parkinson's disease.

In Parkinson's disease, the long-term use of dopamine replacing agents is associated with the development of motor complications; therefore, there is a need for non-dopaminergic drugs. This study evaluated the potential therapeutic impact of six different NR2B and A2A receptor antagonists given either alone or in combination in unilateral 6-OHDA-lesioned rats without (monotherapy) or with (add-on therapy) the co-administration of L-Dopa: Sch-58261+ Merck 22; Sch-58261+Co-101244; Preladenant + Merck 22; Preladenant + Radiprodil; Tozadenant + Radiprodil; Istradefylline + Co-101244. Animals given monotherapy were assessed on distance traveled and rearing, whereas those given add-on therapy were assessed on contralateral rotations. Three-way mixed ANOVA were conducted to assess the main effect of each drug separately and to determine whether any interaction between two drugs was additive or synergistic. Additional post hoc analyses were conducted to compare the effect of the combination with the effect of the drugs alone. Motor activity improved significantly and was sustained for longer when the drugs were given in combination than when administered separately at the same dose. Similarly, when tested as add-on treatment to L-Dopa, the combinations resulted in higher levels of contralateral rotation in comparison to the single drugs. Of special interest, the activity observed with some combinations could not be described by a simplistic additive effect and involved more subtle synergistic pharmacological interactions. The combined administration of A2A/NR2B-receptor antagonists improved motor behaviour in 6-OHDA rats. Given the proven translatability of this model such a combination may be expected to be effective in improving motor symptoms in patients