Federica Crivellente

A cell-based approach for the early assessment of the phospholipidogenic potential in pharmaceutical research and drug development.

Phospholipidosis is a term commonly used to indicate a phospholipid storage disorder; in affected cells, phospholipids accumulate in lysosomes that acquire a multilamellar morphological appearance. Cationic amphiphilic drugs (CADs) are suggested to induce phospholipidosis by direct interaction of xenobiotics with intracellular phospholipids or by the action of xenobiotics on the synthesis and metabolism of phospholipids. To date, electron microscopy (EM) represents the most reliable and the preferred method for the demonstration of phospholipidotic cell damage. Nevertheless, EM has a low throughput, it is expensive, and it is not suitable for screening purposes.We discuss here the assessment of the the phospholipidogenic potential of drugs using a cell culture-based model. In this test, intracellular phospholipids of treated U-937 cells (a human monocyte-derived cell line) were measured using the fluorescent probe Nile red. Eleven CADs reported to induce phospholipidosisin vivo and eight nonphospholipidogenic drugs were tested. Results obtained with the U-937 model confirmed the phospholipidogenic potential of drugs tested as described in the literature. Results have also been correlated with data obtained with a physical-chemical model (chromatographic hydrophobicity index measurement). Good correlation was obtained, confirming that the physical-chemical properties of CADs play a crucial role in the development of phospholipidosis.This work demonstrates that the U-937 model is a rapid and sensitive method for the determination of phospholipidosis-mediated cell damage. The specificity and the predictive potency observed make this method suitable for screening purposes in pharmaceutical development.

Spontaneous Cardiomyopathy in Young Sprague-Dawley Rats: Evaluation of Biological and Environmental Variability

Cardiovascular safety signals in nonclinical studies remain among the main reasons for drug attrition during pharmaceutical research and development. Drug-induced changes can be functional and/or associated with morphological alterations in the normal heart histology. It is therefore crucial to understand the normal variations in histology to discriminate test article–related changes from background lesions. Rodent progressive cardiomyopathy is probably the most commonly encountered change in control animals of nonclinical toxicity studies. A multisite study mimicking standard short-term toxicity studies using young male Sprague-Dawley rats was performed to better characterize this finding. Using an enhanced sectioning method for this research study, it was observed that the incidence of background cardiomyopathy was 100%. The vast majority of the microscopic findings were inflammatory in nature, with associated necrotic changes (defined as necrosis/inflammatory cell infiltrate) and these changes were mainly located in the myocardium of the mid region of the ventricles (the left side being predominantly affected). The monitored environmental factors in this study (multiple facilities, study duration, handling) did not have an effect on the incidence or severity of the spontaneous cardiomyopathy. In addition, cardiac-specific serum troponin levels were measured and were within the published control range.

Analysis of mouse, rat, dog, marmoset, and human serum proteins by capillary electrophoresis: comparison with agarose gel electrophoresis

BACKGROUND Serum protein analysis in both humans and experimental animal species has so far been carried out by labor-intensive techniques, such as agarose gel electrophoresis (AGE). OBJECTIVE The objective of this study was to evaluate capillary electrophoresis (CE) as an alternative technique to AGE for the analysis of serum proteins from healthy animals. METHODS Blood samples were collected into tubes without anticoagulant from 6 fasted healthy male mice, rats, dogs, marmosets, and humans. Serum proteins were separated by CE using a technique standardized for the analysis of human proteins, and the results (efficiency, resolution, and precision) were compared with those obtained through AGE. RESULTS Compared with AGE, CE resulted in narrower peaks and more peaks. The efficiency of protein separation by CE was significantly higher for all species, and resolution (R) was significantly higher in samples from dogs. Using rat serum, intraday reproducibility was lower for all protein fractions, and interday reproducibility was lower for most peaks, compared with AGE. CONCLUSIONS We conclude that CE is a viable alternative to AGE for the determination of protein electrophoresis in a routine veterinary clinical pathology laboratory. The minimal sample requirement (2 microL), complete automation, and quantitative results make CE an especially valuable technique for protein analysis in experimental animal models.

Reduced progression of atherosclerosis in apolipoprotein E-deficient mice treated with lacidipine is associated with a decreased susceptibility of low-density lipoprotein to oxidation.

A study has been carried out in the apolipoprotein (apo) E‐deficient mouse to investigate the activity of lacidipine (a calcium antagonist with antioxidant properties) in inhibiting the development of atherosclerotic lesions; of particular interest were changes in the susceptibility of low‐density lipoproteins (LDL) to oxidation. Mice receiving a Western‐type diet to accelerate the development of atherosclerosis were treated orally with vehicle or lacidipine at 3 or 10 mg/kg/day for 8 weeks. Lacidipine treatment (at 3 or 10 mg/kg) had no effect on the plasma lipid profile. However, a significant (P < 0.01) dose‐related reduction of 43 and 50% of the aortic lesion area in respect to vehicle‐treated mice was observed. Moreover, the resistance of mouse plasma LDL to undergo lipid peroxidation was significantly (P < 0.01) increased in apo E‐deficient mice treated with lacidipine. The native LDL‐like particle, derived from apo E‐deficient mice treated with lacidipine, contained significantly lower concentrations of malonyldialdehyde than the vehicle‐treated control group (P < 0.01). After exposure to human umbilical vein endothelial cells, LDL‐like particle vitamin E levels (expressed as area under the curve; AUC), were significantly higher (P < 0.01) in both the 3 and 10 mg/kg lacidipine‐treated groups, in comparison with the vehicle‐treated control animals. We conclude that lacidipine reduced the extent of the atherosclerotic area in hypercholesterolaemic apo E‐deficient mice, and that this reduction may be associated with the capacity of the drug to decrease the susceptibility of LDL to oxidation.

Involvement of the nitric oxide system in the anti-atherosclerotic potential of lacidipine in the ApoE-deficient mouse: A morphological, functional, and electrochemical study

The present study investigated the anti-atherosclerotic activity of lacidipine, a calcium antagonist with antioxidant properties in apoE-deficient mice. These mice show widespread vascular lesions which closely resemble the inflammatory-fibrous plaques seen in humans in atherosclerosis. Mice were fed a Western-type diet (WTD), and treated for 8 weeks with either vehicle or lacidipine at 3 or 10 mg/kg/day. In parallel with histological studies of atherosclerotic lesions in the aorta, functional studies on vascular acetylcholine (ACh) reactivity and analysis of voltammetric levels of nitric oxide (NO) were performed. Recent work has suggested that dihydropyridines (DHPs) modulate vascular relaxation via an increase in the release of NO. Lacidipine treatment had no effect on the plasma lipid profile. However, a significant (p < 0.01) dose-related reduction of 36.4% and 43.3% of the aortic lesion area in respect to methocel-treated mice was observed. Moreover, the aortic ring from control apoE-deficient mice fed a WTD for 8 weeks showed a lower relaxation in response to ACh in comparison to wild-type C57BL/6J mice; on the contrary, lacidipine-treated apoE-deficient mice lacidipine-treated displayed a response similar to that of wildtype C57BL/6J mice. Voltammetric analyses demonstrated a significant decrease of NO release in apoE-deficient mice, while lacidipine-treated mice showed enhanced activity of the NO system. We conclude that lacidipine reduced the extent of atherosclerotic area in hypercholesterolemic apoE-deficient mice, and this reduction may be associated with the capacity of the drug to maintain endothelial NO levels at concentrations useful to protect against vascular damage.

Molecular biomarkers of phospholipidosis in rat blood and heart after amiodarone treatment

Phospholipidosis (PLD) is characterized by an intracellular accumulation of phospholipids in lysosomes and concurrent development of concentric lamellar bodies. It is induced in humans and in animals by drugs with a cationic amphiphilic structure. The purpose of the present study was to identify a set of molecular biomarkers of PLD in rat blood and heart, hypothetically applicable in preclinical screens within the drug development process. A toxicological study was set up in rats orally treated up to 11 days with 300 mg kg–1 per day–1 amiodarone (AMD). Light and transmission electron microscopy investigations were performed to confirm the presence of lamellar bodies indicative of phospholipid accumulation. The effects of AMD upon the transcriptome of these tissues were estimated using DNA microarray technology. Microarray data analysis showed that a total of 545 and 8218 genes were modulated by AMD treatment in heart and blood, respectively. Some genes implicated in the phospholipid accumulation in cells, such as phospholipase A2, showed similar alterations of gene expression. After transcriptome criteria of analysis and target selection, including also the involvement in the onset of PLD, 7 genes (Pla2g2a, Pla2g7, Gal, Il1b, Cebpb, Fcgr2b, Acer 2) were selected as candidate biomarkers of PLD in heart and blood tissues, and their potential usefulness as a sensitive screening test was screened and confirmed by quantitative Real‐Time PCR analysis. Collectively, these data underscore the importance of transcriptional profiling in drug discovery and development, and suggest blood as a surrogate tissue for possible phospholipid accumulation in cardiomyocytes. Copyright

Atrial natriuretic peptides in Han Wistar, Sprague–Dawley and spontaneously Hypertensive rats

The atrial natriuretic peptide (ANP) and its precursor (N‐terminal fragment of atrial natriuretic peptide, NT‐proANP) are natriuretic peptides released into the circulation as a consequence of an acute atrial stretch. As for the brain natriuretic peptide and its N‐terminal fragment, the biological significance of ANP and NT‐proANP has been widely studied in humans, but the literature is lacking information about the determination of these biomarkers in veterinary medicine and, in particular, in the toxicological species used in preclinical pharmaceutical drug development. This paper describes the evaluation of ANP and NT‐proANP levels in a healthy population of Han Wistar and Sprague–Dawley rats, as well as in a rodent model of hypertension (Spontaneously Hypertensive rats). Both biomarkers were measured by mean of two commercially available enzyme immunoassays and serum levels were correlated with heart weight and histopathological findings in the heart, with the aim of building an integrated assessment of the significance of these biomarkers. Results obtained demonstrated that NT‐proANP and ANP can be accurately measured in the different rat strains, with NT‐proANP concentrations higher than those of ANP, as expected because of its longer half‐life. In addition, both correlated well with cardiac hypertrophy evaluated by means of heart weight and histopathological examination. NT‐proANP and ANP represent reliable markers of cardiac hypertrophy in the rat. Copyright

Peer review of the pesticide risk assessment for the triazole derivative metabolites in light of confirmatory data submitted

Abstract The conclusions of EFSA following the peer review of the initial risk assessment carried out by the competent authority of the rapporteur Member State, the United Kingdom, for the pesticide risk assessment for the triazole derivative metabolites are reported. The context of the peer review was that requested by the European Commission following the submission and evaluation of confirmatory data in relation to mammalian toxicology, metabolism and residue data. The conclusions were reached on the basis of the evaluation of various uses for a number of triazole fungicides. Recommendations are proposed. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Capillary electrophoresis for the detection of bilirubin in rat serum

BACKGROUND The rat is used often to assess the toxicity of new chemical entities in preclinical drug development. Bilirubin concentration in rat serum is routinely determined by colorimetric methods, but false positive results due to hemolyzed serum or direct interferences by test compounds may occur. Capillary electrophoresis (CE) is an automated method that requires small sample volume and facilitates the direct detection of bilirubin. OBJECTIVE The purpose of this study was to evaluate a CE method for detecting bilirubin and albumin-bound bilirubin in rat serum and to measure potential interference by hemolysis and specific test compounds. METHODS Serum samples from male Sprague Dawley rats (n=20) were used in the study. Results obtained on a Beckman P/ACE MDQ CE instrument equipped with a UV-detector were compared with those obtained using a colorimetric method on a Hitachi 912 analyzer. Bilirubin standards were used to evaluate the detection and stability of bilirubin in rat serum, and vials with ultrafiltration membranes were used to separate albumin-bound bilirubin. Intraday and interday coefficients of variation (CV), linearity, and the effects of added hemoglobin and a test compound on CE results were determined. RESULTS The CE method was capable of detecting bilirubin and albumin-bound bilirubin in rat serum samples with reproducible results and good accuracy. CVs were <3% and linearity of the CE assay was high (R(2)=0.9951). Abnormally high bilirubin peaks due to the presence of hemoglobin or the test compound were easily distinguished by means of CE. CONCLUSION CE is a good alternative to the colorimetric methods currently used for the determination of bilirubin in rat serum.

Peer review of the targeted hazard assessment of the pesticide active substance quinoxyfen

Abstract The conclusions of EFSA following the peer review of the initial assessments carried out by the competent authorities of the rapporteur Member State, the United Kingdom, and co‐rapporteur Member State, Austria, for the pesticide active substance quinoxyfen are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. The conclusions were reached on the basis of the evaluation of information targeted at the assessment of the potential persistent, bioaccumulative and toxic (PBT), very persistent and very bioaccumulative (vPvB) and persistent organic pollutant (POP) properties of quinoxyfen according to Article 11(2) of Regulation (EC) No 1107/2009. The reliable end points, appropriate for use in these regulatory hazard cut off assessments are presented. Missing information identified as being required by the regulatory framework is listed. The concern is identified that quinoxyfen may be considered to exhibit the hazard properties of both a PBT and vPvB substance considering the triggers specified in Annex II of Regulation (EC) No 1107/2009.