A new clinically-relevant rat model of letrozole-induced chronic nociceptive disorders.

Among postmenopausal women with estrogen receptor-positive breast cancer, more than 80% receive hormone therapy including aromatase inhibitors (AIs). Half of them develop chronic arthralgia - characterized by symmetric articular pain, carpal tunnel syndrome, morning stiffness, myalgia and a decrease in grip strength - which is associated with treatment discontinuation. Only a few animal studies have linked AI treatment to nociception, and none to arthralgia. Thus, we developed a new chronic AI-induced nociceptive disorder model mimicking clinical symptoms induced by AIs, using subcutaneous letrozole pellets in ovariectomized (OVX) rats. Following plasma letrozole dosage at the end of the experiment (day 73), only rats with at least 90 ng/ml of letrozole were considered significantly exposed to letrozole (OVX + high LTZ group), whereas treated animals with less than 90 ng/ml were pooled in the OVX + low LTZ group. Chronic nociceptive disorder set in rapidly and was maintained for more than 70 days in the OVX + high LTZ group. Furthermore, OVX + high LTZ rats saw no alteration in locomotion, myalgia or experimental anxiety during this period. Bone parameters of the femora were significantly altered in all OVX rats compared to Sham+vehicle pellet. A mechanistic analysis focused on TRPA1, receptor suspected to mediate AI-evoked pain, and showed no modification in its expression in the DRG. This new long-lasting chronic rat model, efficiently reproduces the symptoms of AI-induced nociceptive disorder affecting patients' daily activities and quality-of-life. It should help to study the pathophysiology of this disorder and to promote the development of new therapeutic strategies.

Minimizing chemotherapy-induced peripheral neuropathy: preclinical and clinical development of new perspectives.

INTRODUCTION: Chemotherapy-induced peripheral neuropathies (CIPN) are a dose-limiting adverse effect of certain anticancer drugs (platinum salts, vinca alkaloids, taxanes, bortezomib, thalidomide, epothilones, eribulin). CIPN are mainly responsible for sensory disturbances and are associated with a decrease in quality of life. After the end of chemotherapy, CIPN can last for several months and even years. Unfortunately, recent meta-analyses of clinical trials have demonstrated that there is no univocal gold standard for the prevention and treatment of CIPN. AREAS COVERED: Using animal models of CIPN, several new strategies to prevent or treat CIPN are under development. These new strategies involve several pathways, including ion channels, neuroprotectants, glutamatergic neurotransmission, oxidative stress, cannabinoid system, inflammation, and mitochondrial functions. EXPERT OPINION: To date, based on meta-analyses of clinical trials, no drug can be proposed as a gold standard to prevent or treat CIPN. Consequently, there is a strong discrepancy between the optimistic results of animal studies and the poor outcomes of clinical trials. Pain assessment in preclinical and clinical studies is probably not the best outcome measurement tool and all these studies should include composite outcomes including the full complexity of CIPN symptoms, such as positive symptoms (pain, paresthesia, and dysesthesia) and negative ones (numbness).

Prevention of oxaliplatin-induced peripheral neuropathy by a polyamine-reduced diet-NEUROXAPOL: protocol of a prospective, randomised, controlled, single-blind and monocentric trial.

INTRODUCTION: Oxaliplatin remains the most widely used chemotherapeutic agent for treating advanced colorectal cancer but its efficacy is hampered by dose-limiting neurotoxicity manifested by a painful polyneuropathy. Oxaliplatin-induced peripheral neuropathy (OIPN) is characterised by acute and transient cold hyperaesthesia in the hours and days following oxaliplatin infusion (>90% of patients), but also by retarded chronic neuropathy due to the repetition of chemotherapy cycles (30-50% of patients). OIPN impairs the health-related quality of life (HRQOL) of patients and no preventive or curative strategies have as yet proven effective. A polyamine-reduced diet (PRD) has recently demonstrated its efficacy to prevent OIPN in animals without adverse effects. METHODS AND ANALYSIS: The NEUROXAPOL trial is a prospective, randomised, controlled, single-blind, monocentric and interventional study. This trial is aimed at evaluating the efficacy and feasibility of a PRD compared to a normal polyamine containing diet to prevent OIPN in patients treated by oxaliplatin-based chemotherapy. Patients (n=40 per group) will be randomly assigned to receive either a PRD or a normal diet before and during the chemotherapy regimen. The main objectives are to improve the cold pain thresholds, neuropathic pain symptoms, comorbidities (anxiety and depression) and HRQOL of patients. The primary end point is the assessment of cold pain thresholds 2 weeks after the third cycle of chemotherapy. The secondary end points are the evaluation of thermal pain thresholds, the grade of neuropathy, neuropathic pain, symptoms of anxiety and depression and HRQOL, until the 12th cycle of chemotherapy. ETHICS AND DISSEMINATION: The study was approved by an independent medical ethics committee 1 (CPP Sud Est 1, Saint Etienne, France) and registered by the competent French authority (ANSM, Saint Denis, France). The results will be disseminated in a peer-reviewed journal and presented at international congresses. TRIAL REGISTRATION NUMBER: NCT01775449.

Use of domperidone as a galactagogue drug: a systematic review of the benefit-risk ratio.

Breastfeeding is the optimal method for feeding a newborn. However, some mothers may have difficulties lactating. Domperidone is widely used as a galactagogue but to the best of our knowledge has not been approved by any health authority. The objective of this review was to assess the benefit-risk ratio of domperidone for stimulating lactation. The benefit-risk ratio of domperidone as a galactagogue was assessed following a literature search of the PubMed database up to July 2013. Four studies were selected to assess domperidone efficacy and demonstrated an increased milk production. The limited data (60 mother-baby pairs) and the moderate methodological quality of 1 study remain insufficient to conclude on domperidone efficacy. Regarding the safety of domperidone, 7 studies were selected that exposed 113 infants to domperidone through breastfeeding. No adverse effects were observed in 85 infants, and no information was provided for the remaining 28. The limited data available remain in favor of a safe domperidone profile in infants and mothers. However, in large studies focused on gastrointestinal disorders, domperidone is responsible for drug-induced long QT syndrome and sudden cardiac death. The use of domperidone as a galactagogue is worrisome as drug-induced long QT syndrome occurred mostly in women. In these circumstances, an improvement of breastfeeding practices seems to be more effective and safer than the use of an off-label domperidone treatment.

Bioaccumulation of chlorophacinone in strains of rats resistant to anticoagulants.

BACKGROUND: Anticoagulants are the only available compounds in the EU to control rat populations. Resistance to anticoagulant rodenticides (antivitamin K or AVK) is described and widespread across Europe. The present objective was to determine whether resistance was associated with an increased potential for bioaccumulation of AVK in the liver. Rats were selected from three major resistant genetically identified strains across Europe: Y139C (Germany), Y139F (France) and L120Q (United Kingdom). The rats were housed in individual cages and fed chlorophacinone wheat bait (50 mg kg(-1) ). Animals were assigned to groups for euthanasia either on day 1, 4, 9 or 14 (resistant rats) or on days 1 and 4 (susceptible rats). RESULTS: Chlorophacinone accumulated from day 1 to day 4 in all strains (maximum 160 µg liver(-1)) and remained stable thereafter. There was no significant difference between strains. Extensive metabolism of chlorophacinone was also found, and was similar (in nature and proportion of metabolites) across strains (3 OH-metabolites identified). Only the survival time differed significantly (L120Q > Y139C = Y139F > susceptible). CONCLUSIONS: Accumulation of chlorophacinone occurs from day 1 to day 4, and an equilibrium is reached, suggesting rapid elimination. Resistant and susceptible rats accumulate chlorophacinone to the same extent and only differ in terms of survival times. Resistant rats may then be a threat for non-target species for prolonged periods of time.

Adaptation of a real-time PCR method for the detection and quantification of pathogenic leptospires in environmental water.

Leptospirosis is a major zoonotic disease that affects humans and animals in all continents, in both rural and urban areas. In Europe, metropolitan France is the most affected country, with about 300 human cases declared per year. In France, although leptospirosis is now mostly considered as a recreational disease related to freshwater areas, isolation of pathogenic leptospires from environmental water samples still remains difficult. It thus seemed important to set up an efficient method to detect and quantify these bacteria in this environment. We determined a DNA extraction method suitable for freshwater samples and adapted a real-time quantitative PCR based on the detection of the LipL32 gene using the SYBR green chemistry. The method developed is specific for pathogenic Leptospira. It permits the detection of all the pathogenic strains tested and none of the saprophytic strains. Quantification is possible between 10 and 10(7) bacteria/mL, and therefore, the method represents a tool that could be integrated into future public health surveillance programs for recreational freshwater areas.

Are water vole resistant to anticoagulant rodenticides following field treatments?

The anti-vitamin Ks (AVKs) are widely used to control rodent populations. They inhibit Vitamin K regeneration by the Vitamin K Epoxide Reductase (VKOR) and cause a fatal hemorrhagic syndrome. Because of repeated use, some populations of commensal rodents have expressed resistance to these compounds. In Franche-Comté (France), the water vole exhibits cyclic population outbreaks. A second generation AVK, bromadiolone, has been used for the last 20 years to control vole populations. The aim of this study is to determine whether these repeated treatments could have led to the development of resistance to AVKs in water vole populations. We conducted enzymatic and genetic studies on water voles trapped in treated and non treated plot. The results indicate that voles from the most heavily treated area exhibit enzymatic changes in VKOR activity hence arguing for resistance to AVKs and that an intronic haplotype on the vkorc1 gene seems to be associated with these enzymatic changes.