Gold(III)-dithiocarbamato complexes have recently gained increasing attention as potential anticancer agents because of their strong tumor cell growth-inhibitory effects, generally achieved by exploiting non-cisplatin-like mechanisms of action. The rationale of our research work is to combine the antitumor properties of the gold(III) metal center with the potential chemoprotective function of coordinated dithiocarbamates in order to reduce toxic side effects (in particular nephrotoxicity) induced by clinically established platinum-based drugs. In this context, [Au III Br 2 (ESDT)] (AUL12) was proved to exert promising and outstanding antitumor activity in vitro and to overcome both acquired and intrinsic resistance showed by some types of tumors toward cisplatin. As a subsequent extension of our previous work, we here report on detailed in vivo studies in rodents, including antitumor activity toward three transplantable murine tumor models, toxicity, nephrotoxicity and histopathological investigations. Remarkably, the gold(III) complex AUL12 stands out for higher anticancer activity than cisplatin toward all the murine tumor models examined, inducing up to 80% inhibition of tumor growth. In addition, it shows low acute toxicity levels (lethal dose, LD 50 5 30 mg kg 21 ) and reduced nephrotoxicity. Altogether, these results confirm the reliability of our drug design strategy and support the validation of this gold(III)-dithiocarbamato derivative as a suitable candidate for clinical trials.The accidental discovery of the anticancer properties of cisplatin (cis-dichlorodiammineplatinum(II), cis-[Pt II Cl 2 (NH 3 ) 2 ]; Fig. 1) in the mid-1960s 1 has triggered the development of both platinum 2 -and other metal-based 3,4 alternative compounds. Although well-established in current cancer chemotherapy, the use of platinum compounds for the treatment of tumor diseases is massively hampered by severe side effects such as nausea, alopecia, ototoxicity, neurotoxicity, myelosuppression, nephrotoxicity and tumor resistance, either intrinsic or acquired during cycles of therapy. 5 Consequently, the development of novel metallodrugs showing a different pharmacological profile is a major goal of modern medicinal chemistry and drug design.Among the non-platinum antitumor agents, gold complexes have recently gained increasing attention because of their strong inhibitory effects on tumor cell growth, generally achieved by exploiting non-cisplatin-like pharmacodynamic and pharmacokinetic properties and mechanisms of action. 6,7 Owing to their traditional use in medicine for the treatment of rheumatoid arthritis, gold derivatives are suitable candidates as potential alternatives to platinum drugs. In fact, the antiarthritic activity arises from their known immunosuppressive and anti-inflammatory actions, thus establishing, at least in principle, a connection between the two therapies. Moreover, gold(III) complexes show chemical features that are very close to those of clinically established platinum(II) derivatives, such as the pre...

Cardiovascular toxicity represents one of the major reasons for the termination of the development of drugs, even in late development phases. This growing issue is often not restricted to specific therapeutic areas, and it is gaining critical importance, in particular for chronically administered drugs, highlighting the limitations in terms of sensitivity of the current investigational paradigms. Furthermore, drug-related changes may become evident after long-term administration for different reasons, including accumulation of the drug in the heart. This article describes how the integrated use of investigational tools represents a powerful approach for the early identification and characterization of cardiotoxicity in preclinical development. Cardiac changes were observed in the dog after long-term oral administration of casopitant, a neurokinin 1 receptor antagonist, developed for the treatment of depression and anxiety. Different approaches and sensitive biomarkers were used in a time-course study to investigate the onset, progression, and reversibility of the lesion. The integrated evaluation of cardiovascular parameters, electron microscopy, troponin I, and natriuretic peptide results highlighted any minimal early changes, allowing the full and deep characterization of the lesion. The outcome of this study was the driver for drug development decision making on casopitant and backup drugs.

In dogs Helicobacter spp. are found in all gastric regions usually localized in the surface mucus, gastric glands and parietal cells. The aim of this study was to detail the distribution of Helicobacter spp. in the fundic mucosa of asymptomatic Beagle dogs and their intracellular localization within parietal cells, in order to evaluate species-specific pathogenetic effects on gastric cells. The presence of Helicobacter spp. was investigated by immunohistochemistry, TEM, and PCR in the fundic mucosa of six Beagle dogs. Helicobacter spp. were found in all dogs examined, and H. bizzozeronii and H. felis were identified by PCR and confirmed by TEM. In the lumen of the fundic glands, co-localization was common. H. bizzozeronii was present in larger numbers than H. felis in both intraluminal and intraparietal localization. The amounts of H. bizzozeronii were similar in superficial and basal portions of the glands. H. felis was predominantly localized in the superficial portions of gastric glands but almost absent from the base. Within parietal cells, most Helicobacter organisms were intracanalicular, but intact and degenerate Helicobacter organisms were also visualized free in the cytoplasm or in secondary lysosomes. No specific degenerative lesions were found in infected parietal cells. Helicobacter organisms were also observed within macrophages in the lamina propria. In conclusion, there is a differential distribution of H. bizzozeronii and H. felis in the fundic mucosa of Beagle dogs, and their intracellular localization in parietal cells and macrophages suggests novel pathogenic scenarios for the development of immune response and maintenance of chronic gastritis in dogs.

Although occurring in aged laboratory rodents, spontaneous renal tumour are unknown in animals younger than 18 weeks. A survey on renal preneoplastic and neoplastic lesions has been performed on Sprague-Dawley rats from general toxicology studies over the period January 2004 - May 2006. Data from 2249 rats necropsied and 1206 rats (688 males and 518 females) examined microscopically from 52 studies, are reported. The age range at necropsy was between 12 and 18 weeks and all the animals were obtained from the same supplier. Three cases of tubular carcinoma, 1 tubular adenoma, and 4 cases of atypical tubular hyperplasia were observed in 5 females and 3 males from both control and treated groups from 6 studies with unrelated test compounds. In treated rats, the lesions were considered spontaneous in nature, rather than related to treatment, because of: (1) their sporadic incidence, (2) the short duration of the studies, and (3) the absence of similar lesions in other rats given the same test compound. These lesions are considered a recently occurring spontaneous finding, and the similarities with the familial renal cancer models, namely the Eker and the Nihon models, strongly suggest genetic factors as responsible for the lesions.

A flow cytometry method, to monitor peripheral lymphocytes phospholipidosis, has been set up using a single staining with Nile red and double staining with Nile red and anti-CD3 monoclonal antibody. Blood has been collected from rats treated with amiodarone (phospholipidogenic antiarrhythmic drug). By flow cytometer, it is possible to detect phospholipids, using Nile red, a probe for intracellular lipids staining, changing its fluorescence on the stained lipid basis. CD3 antigen has been selected to focus on T cells, to evaluate whether these cells are the target of phospholipidosis amiodarone-dependent. In the study A, Sprague-Dawley rats were treated with three different doses (75, 150, and 300 mg kg(-1) day(-1)) of amiodarone or vehicle alone, for 14 days, followed by 14 days of recovery: Data obtained show that by flow cytometry, with Nile red alone, it is possible to detect a dose- and time-related response of phospholipidosis-positive lymphocytes; a partial recovery is also assessed. In the study B, Sprague-Dawley rats were treated with a single dose (300 mg kg(-1) day(-1)) of amiodarone, for 14 days: Data obtained show that animals treated with amiodarone have a significant increase of phospholipidosis-positive lymphocytes (p = 0.008), in particular of CD3+ cells (p = 0.0056). Transmission electron microscopy analysis confirmed data obtained by flow cytometry. This work shows that flow cytometry with Nile red could be a good tool to monitor ex vivo phospholipidosis in lymphocyte cells of animals treated with amiodarone: The phospholipidogenic effect is more evident focusing on CD3+ T lymphocytes, thus suggesting that these cells are probably the target of phospholipidosis.