Human matrix metalloproteinases: An ubiquitarian class of enzymes involved in several pathological processes

Human matrix metalloproteinases (MMPs) belong to the M10 family of the MA clan of endopeptidases. They are ubiquitarian enzymes, structurally characterized by an active site where a Zn(2+) atom, coordinated by three histidines, plays the catalytic role, assisted by a glutamic acid as a general base. Various MMPs display different domain composition, which is very important for macromolecular substrates recognition. Substrate specificity is very different among MMPs, being often associated to their cellular compartmentalization and/or cellular type where they are expressed. An extensive review of the different MMPs structural and functional features is integrated with their pathological role in several types of diseases, spanning from cancer to cardiovascular diseases and to neurodegeneration. It emerges a very complex and crucial role played by these enzymes in many physiological and pathological processes

Die Entwicklung und Anwendung neuer Methoden und Strategien fuer das 'Monitoring' von Nephrotoxizitaet und die Studie der Nierenphysiologie: Auf Proteom- und Metabonomanalyse basierende Studien

A Key for avoiding the negative effects of immunosuppressant caused nephropathy after transplantation is early detection. This study shows a set of biomarkers, which could serve for the early detection of nephrotoxicity. Systematic development of a new model enables for the evaluation of drug induced nephrotoxicity and could be used for the development of new drugs in an early phase. We found indicators for the drug induced formation of reactive oxygen species, which could be causing the toxicity. The NMR-based model correlated with the 8-isoprostaglandin-F2aplha levels and the glomerular filtration rates showing the trend in toxicity:control<sirolimus<=tacrolimus<Sirl. Tac.<cyclosporine<Sirl. cylosporine. The combination of calcineurin inhibitors with sirolimus shows synergistic toxicity and that the combination of tacrolimus with sirolimus is favorable compared to cyclosporine with sirolimus.Investigations on changes caused by hyperosmotic stress in inner medullary collecting duct cells showed the importance of sorbitol and the polyol pathway as the most important mechanism in an environment of 900 mOsm/KgH2O media tonicit

The Development and Use of New Methods and Strategies for the Monitoring of Nephrotoxicity and the Study of Renal Physiology: Proteomics- and Metabonomics-based Studies

A Key for avoiding the negative effects of immunosuppressant caused nephropathy after transplantation is early detection. This study shows a set of biomarkers, which could serve for the early detection of nephrotoxicity. Systematic development of a new model enables for the evaluation of drug induced nephrotoxicity and could be used for the development of new drugs in an early phase. We found indicators for the drug induced formation of reactive oxygen species, which could be causing the toxicity. The NMR-based model correlated with the 8-isoprostaglandin-F2aplha levels and the glomerular filtration rates showing the trend in toxicity:control<sirolimus<=tacrolimus<Sirl. Tac.<cyclosporine<Sirl. cylosporine. The combination of calcineurin inhibitors with sirolimus shows synergistic toxicity and that the combination of tacrolimus with sirolimus is favorable compared to cyclosporine with sirolimus.Investigations on changes caused by hyperosmotic stress in inner medullary collecting duct cells showed the importance of sorbitol and the polyol pathway as the most important mechanism in an environment of 900 mOsm/KgH2O media tonicit

Mycophenolate mofetil enhances the negative effects of sirolimus and tacrolimus on rat kidney cell metabolism.

Mycophenolate mofetil (MMF) per se is not known to have negative effects on the kidney. MMF alone or in combination with sirolimus, can be the basis of calcineurin inhibitor (CNI)-free, kidney sparing drug protocols. However, long-term outcomes in patients on MMF/SRL seem to be inferior to those treated with regimens that include the CNI tacrolimus (TAC) due to an increased risk of allo-immune reactions. Interestingly, potential enhancement of the negative effects of SRL and TAC on the kidney by MMF has never been considered.It was our aim to study the effects of TAC, SRL and MMF alone and evaluate their interactions when combined on the rat kidney. For this purpose we used a comprehensive molecular marker approach including measurements of urinary 8-isoprostane concentrations (oxidative stress marker) and changes of urinary metabolite patterns ((1)H-NMR spectroscopy) and comparing these markers to renal function (glomerular filtration rate (GFR)) and morphologic alterations (histology).While MMF alone did not impact GFR, its interaction with SRL and TAC led to a significant decrease of rats' renal function. The decline went in parallel with a significant increase in urinary isoprostane concentrations and an enhancement of negative effects on urinary metabolite patterns.In broad summary, the present study showed that MMF may enhance the negative effects of TAC on kidney function and may even display nephrotoxic properties when combined with SRL

Identification and Characterization of Cannabichromene’s Major Metabolite Following Incubation with Human Liver Microsomes

Cannabichromene (CBC) is a minor cannabinoid within the array of over 120 cannabinoids identified in the Cannabis sativa plant. While CBC does not comprise a significant portion of whole plant material, it is available to the public in a purified and highly concentrated form. As minor cannabinoids become more popular due to their potential therapeutic properties, it becomes crucial to elucidate their metabolism in humans. Therefore, the goal of this was study to identify the major CBC phase I-oxidized metabolite generated in vitro following incubation with human liver microsomes. The novel metabolite structure was identified as 2′-hydroxycannabicitran using gas chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy. Following the identification, in silico molecular modeling experiments were conducted and predicted 2′-hydroxycannabicitran to fit in the orthosteric site of both the CB1 and CB2 receptors. When tested in vitro utilizing a competitive binding assay, the metabolite did not show significant binding to either the CB1 or CB2 receptors. Further work necessitates the determination of potential activity of CBC and the here-identified phase I metabolite in other non-cannabinoid receptors

The Fatty Acid Desaturation Index in Human Plasma: Comparison of Different Analytical Methodologies for the Evaluation of Dietary Effects

Abstract (252 words) Background: Stearoyl-CoA Desaturase (SCD1) plays a role in the development of obesity and related conditions, such as insulin resistance, and potentially also in neurological and heart diseases. The activity of SCD1 can be monitored using the desaturation index (DI), the ratio of product (16:1n-7 and 18:1n-9) to precursor (16:0 and 18:0) fatty acids. Here we analyzed the DI in the plasma total triglyceride fraction and very low density lipoproteins (VLDL) in volunteers on a high carbohydrate diet using a dual ultra-high pressure liquid chromatography – mass spectrometry (UHPLC-MS) strategy. Methods: One assay was based on a simple extraction followed by neutral loss triglyceride – fatty acid analysis, the other on saponification of triglycerides followed by fatty acid analysis (specific for the position of the double bond within monosaturated fatty acids (MUFA). Both assays were applied to the isolated VLDL or to the plasma total triglyceride fraction. Assays were compared using plasma from a study in which 8 lean and obese healthy individuals received a high carbohydrate diet for 3 days. Results: All assays showed acceptable accuracies (75-125) and precisions (<20%) for the analysis of fatty acids in VLDL and plasma. Analysis of human plasma samples revealed increased DI (up to 136% of control, p< 0.05 after a high carbohydrate diet of 3 days. Conclusion: Only the specific fatty acid UHPLC-MS analysis of human plasma VLDL samples reflects the complete biological pathway and showed that a significant increase in DI and associated SCD1 activity –in healthy individuals after just 3 days of high carbohydrate diet