Adverse drug reactions: analysis of spontaneous reporting system in Europe in 2007-2009.

PURPOSE: Spontaneous reporting systems in European countries are crucial for collecting adverse drug reaction (ADR) reports. The aim of this study was to evaluate reporting activity among countries and their strategy to increase the number of reports. We also established the best measure for assessment quantity of reports. METHODS: This was a retrospective observational study based on questionnaires and annual reports. The most reliable measure of reporting was determined by Spearman correlation coefficients. RESULTS: Data collected in spontaneous reporting systems in 26 European countries were analysed. In 2007, 2008 and 2009, the average value of reports per year per million inhabitants based on the safety databases of countries was 208, 236, 286, respectively; in comparison, that of Eudra- Vigilance was 311, 453 and 435, respectively. Twelve countries reached a significant level for signal detection of ADRs in 2009. The population-based reporting ratio (PBRR) was correlated to the total expenditure on health (ρ=0.499, p=0.023, n=21), public expenditure on health (ρ=0.477, p=0.035, n=20), density of physicians (ρ=0.336, p=0.136, n=21) and expenditure on pharmaceuticals (ρ=0.365, p=0.114, n=20). Strategies of regulatory authorities to increase reporting were determined. CONCLUSIONS: The results of this study make several noteworthy contributions regarding national spontaneous reporting systems. The relevance of the PBRR for the measurement reporting activity is clearly supported by the current findings. This study also shows that there is a general trend towards increased reporting activity. This is maintained by regional centres and encouragement of reporting. A further study would be helpful to assess the effectiveness of reporting systems at both the national and European level.

IrCL1 - the haemoglobinolytic cathepsin L of the hard tick, Ixodes ricinus.

Intracellular proteolysis of ingested blood proteins is a crucial physiological process in ticks. In our model tick, Ixodes ricinus, cathepsin L (IrCL1) is part of a gut-associated multi-peptidase complex; its endopeptidase activity is important in the initial phase of haemoglobinolysis. We present the functional and biochemical characterisation of this enzyme. We show, by RNA interference (RNAi), that cathepsin L-like activity that peaks during the slow feeding period of females is associated with IrCL1. Recombinant IrCL1 was expressed in bacteria and yeast. Activity profiling with both peptidyl and physiological protein substrates (haemoglobin and albumin) revealed that IrCL1 is an acidic peptidase with a very low optimum pH (3-4) being unstable above pH 5. This suggests an endo/lysosomal localisation that was confirmed by indirect fluorescence microscopy that immunolocalised IrCL1 inside the vesicles of digestive gut cells. Cleavage specificity determined by a positional scanning synthetic combinatorial library and inhibition profile indicated that IrCL1 has the ligand-binding characteristics of the cathepsin L subfamily of cysteine peptidases. A non-redundant proteolytic function was demonstrated when IrCL1-silenced ticks had a decreased ability to feed compared with controls. The data suggest that IrCL1 may be a promising target against ticks and tick-borne pathogens.

Hemoglobin digestion in blood-feeding ticks: mapping a multipeptidase pathway by functional proteomics.

Hemoglobin digestion is an essential process for blood-feeding parasites. Using chemical tools, we deconvoluted the intracellular hemoglobinolytic cascade in the tick Ixodes ricinus, a vector of Lyme disease and tick-borne encephalitis. In tick gut tissue, a network of peptidases was demonstrated through imaging with specific activity-based probes and activity profiling with peptidic substrates and inhibitors. This peptidase network is induced upon blood feeding and degrades hemoglobin at acidic pH. Selective inhibitors were applied to dissect the roles of the individual peptidases and to determine the peptidase-specific cleavage map of the hemoglobin molecule. The degradation pathway is initiated by endopeptidases of aspartic and cysteine class (cathepsin D supported by cathepsin L and legumain) and is continued by cysteine amino- and carboxy-dipeptidases (cathepsins C and B). The identified enzymes are potential targets to developing novel anti-tick vaccines.