Edi Simoni

Correlation of adverse effects of cisplatin administration in patients affected by solid tumours: A retrospective evaluation

Cisplatin is the most common antineoplastic drug used for the therapy of solid tumours. To date, researchers have focused on the dosage to be administered for each specific tumour, mainly considering the local adverse effects. The aim of this study was to correlate the severity of the adverse effects with: i) the dosage of cisplatin; ii) the specific site of the tumour; iii) the association with other drugs; and iv) the symptoms. We analysed data from 123 patients with 11 different tumour classes undergoing therapy from 2007 to 2008 at St. Anna Hospital (Ferrara, Italy), using the Spearman non-parametric correlation index. Even though significant correlations were found among the variables, the overall results showed that the main factor influencing the severity of the adverse effects was the dosage of cisplatin administered.

Cochlear implants and drug delivery: In vitro evaluation of dexamethasone release.

Anti-inflammatory drugs can minimize the trauma and inflammation in the inner ear caused by cochlear implantation surgery. For this reason, much effort has recently been devoted to finding the best way to administer these anti-inflammatory drugs for a prolonged time and in a personalized dosage. One solution is constructing an electrode with a dispenser filled with anti-inflammatory drugs with a dosage adapted to suit each new cochlear implant user. The purpose of this study was to measure in vitro, by high-performance liquid chromatography-mass spectrometry assay, the amount of dexamethasone released in 78 days in a physiological solution by a filled dispenser. The drug release continued for more than 2 months in three different phases: (1) during the first 1-5 days, (2) within about 2 weeks, and (3) from about 3 weeks until the end of experiment. This release trend is in accordance with the 3 main phases of damage caused by the cochlear implantation: (1) insertion trauma within the first 2 days, (2) inflammation within 2 weeks, and finally (3) an intracochlear chronic fibrosis reaction. Future animal model studies should consider using this dispenser in order to establish its effectiveness in preventing damage caused by cochlear implantation.

Association between idiopathic hearing loss and mitochondrial DNA mutations: a study on 169 hearing-impaired subjects.

Mutations in mitochondrial DNA (mtDNA) have been shown to be an important cause of sensorineural hearing loss (SNHL). In this study, we performed a clinical and genetic analysis of 169 hearing-impaired patients and some of their relatives suffering from idiopathic SNHL, both familial and sporadic. The analysis of four fragments of their mtDNA identified several polymorphisms, the well known pathogenic mutation, A1555G, and some novel mutations in different genes, implying changes in the aminoacidic sequence. A novel sporadic mutation in 12S rRNA (MT-RNR1), not previously reported in the literature, was found in a case of possible aminoglycoside-induced progressive deafness.

Coenzyme Q10 plus Multivitamin Treatment Prevents Cisplatin Ototoxicity in Rats

Cisplatin (Cpt) is known to induce a high level of oxidative stress, resulting in an increase of reactive oxygen species damaging the inner ear and causing hearing loss at high frequencies. Studies on animal models show that antioxidants may lower Cpt-induced ototoxicity. The aim of this study is to evaluate the ototoxic effects of two different protocols of Cpt administration in a Sprague-Dawley rat model, and to test in the same model the synergic protective effects of a solution of coenzyme Q10 terclatrate and Acuval 400®, a multivitamin supplement containing antioxidant agents and minerals (Acu-Qter). The Cpt was administered intraperitoneally in a single dose (14 mg/kg) or in three daily doses (4.6 mg/kg/day) to rats orally treated or untreated with Acu-Qter for 5 days. The auditory function was assessed by measuring auditory brainstem responses from 2 to 32 kHz at day 0 and 5 days after treatment. Similar hearing threshold and body weight alterations were observed in both Cpt administration protocols, but mortality reduced to zero when Cpt was administered in three daily doses. The Acu-Qter treatment was able to prevent and completely neutralize ototoxicity in rats treated with three daily Cpt doses, supporting the synergic protective effects of coenzyme Q terclatrate and Acuval 400® against Cpt-induced oxidative stress. The administration protocol involving three Cpt doses is more similar to common human chemotherapy protocols, therefore it appears more useful for long-term preclinical studies on ototoxicity prevention.

Regenerative medicine in hearing recovery

Hearing loss, or deafness, affects 360 million people worldwide of which about 32 million are children. Deafness is irreversible when it involves sensory hair cell death because the regenerative ability of these cells is lost in mammals after embryo development. The therapeutic strategies for deafness include hearing aids and/or implantable devices. However, not all patients are eligible or truly benefit from these medical devices. Regenerative medicine based on stem cell application could play a role in both improvement of extant medical devices and in vivo recovery of auditory function by regeneration of inner ear cells and neurons. A review of recent literature on the subject indicates that two promising approaches to renewal and differentiation of cochlear tissues are transplantation of stem cells and in situ administration of growth factors. Rather than directly regenerating dead cells, these procedures apparently induce, through various pathways, differentiation of resident cochlear cells. More studies on the possible adverse effects of transplanted cells and the recovery of tonotopic sensorineural activity or required. To date, no reliable clinical results have been obtained in the field of cochlear regeneration.

Human mesenchymal stromal cell therapy for damaged cochlea repair in nod-scid mice deafened with kanamycin

BACKGROUND Kanamycin, mainly used in the treatment of drug-resistant-tuberculosis, is known to cause irreversible hearing loss. Using the xeno-transplant model, we compared both in vitro and in vivo characteristics of human mesenchymal stromal cells (MSCs) derived from adult tissues, bone marrow (BM-MSCs) and adipose tissue (ADSCs). These tissues were selected for their availability, in vitro multipotency and regenerative potential in vivo in kanamycin-deafened nod-scid mice. METHODS MSCs were isolated from informed donors and expanded ex vivo. We evaluated their proliferation capacity in vitro using the hexosaminidase assay, the phenotypic profile using flow-cytometry of a panel of surface antigens, the osteogenic potential using alkaline phosphatase activity and the adipogenic potential using oil-red-O staining. MSCs were intravenously injected in deafened mice and cochleae, liver, spleen and kidney were sampled 7 and 30 days after transplantation. The dissected organs were analyzed using lectin histochemistry, immunohistochemistry, polymerase chain reaction (PCR) and dual color fluorescence in situ hybridization (DC-FISH). RESULTS MSCs showed similar in vitro characteristics, but ADSCs appeared to be more efficient after prolonged expansion. Both cell types engrafted in the cochlea of damaged mice, inducing regeneration of the damaged sensory structures. Several hybrid cells were detected in engrafted tissues. DISCUSSION BM-MSCs and ADSCs showed in vitro characteristics suitable for tissue regeneration and fused with resident cells in engrafted tissues. The data suggest that paracrine effect is the prevalent mechanism inducing tissue recovery. Overall, BM-MSCs and ADSCs appear to be valuable tools in regenerative medicine for hearing loss recovery.

OC-k3 cells, an in vitro model for cochlear implant biocompatibility

Objective: In patients with severe or deep hypoacousis, the cochlear implant represents the only way to recover the ability to hear. Nevertheless, the insertion of a silicone-embedded electrode in the cochlea may produce damage through pressure, shock, bleeding and tissue perforation, which could cause apoptosis and necrosis in the organ of Corti. Another variable is the use of different silicone materials. Although all embedding silicone compounds are medical grade biocompatible, their effects in the inner ear environment have never been tested. Our aim was to assess whether polydimethylsiloxane (PDMS) compounds employed in cochlear implants could be cytotoxic to inner ear cells, by exposing an in vitro organ of Corti cell line (OC-k3) to four PMDS compounds (three fluid and one elastomere) and verifying whether or not any one of these compounds could lead to cell death by apoptosis or necrosis. Study design: To obtain a toxicity curve, OC-k3 cells were exposed to PDMS compounds (octadimethylsiloxane, hexadimethylsiloxane, decamethylcyclopentasiloxane and a silicon rod) at different dilutions and time of exposure, testing vitality by flux cytofluorometry and fluorescence microscopy. Investigations were extended to molecular interactions between OC-k3 cells and PDMS, testing cell death markers by immunocytochemistry and real-time PCR. Results: Among the fluid PDMS compounds, decamethylcyclopentasiloxane induced the highest significant cell mortality (at 1:100 dilution) after 48 h of treatment, followed by octadimethylsiloxane (1:10) and hexadimethylsiloxane (1:5) at 24 h. The silicon rod did not show any inner ear cell toxicity. Conclusion: In our experimental conditions, the observed cell mortality was not caused by release of cytotoxic molecules by PDMS on OC-k3 cells, but by the formation by PMDS of a surface film preventing air exchange. From a biomolecular point of view, PDMS compounds appear suitable for electrode coating in cochlear implants.

Evaluation of toxicity of glycerol monooleate nanoparticles on PC12 cell line

An innovative approach to improve drug delivery is the use of glycerol monooleate nanoparticles. Numerous studies describe their high versatility, low toxicity and ability to carry relatively high loads of conjugated compounds including scarcely soluble ones, providing sustained drug release and increasing drug diffusion and half-life. Despite a growing interest in their potential use for therapeutic applications, there are surprisingly few literature data concerning the toxic effects of these nanoparticles at high concentrations in vitro and in vivo, and their effects on cell metabolism. We produced and characterized from a physical-chemical point of view glycerol monooleate nanoparticles and tested them on the PC12 cell line, a rat model of neuronal differentiation. The toxicity of these nanoparticles was evaluated by molecular methods on cell viability, cell cycle, nanoparticle uptake and induction of apoptosis. The results showed that glycerol monooleate nanoparticles up to 100 μg/mL had no toxic effects on PC12 cells, did not induce significant changes in the cell cycle nor cause apoptosis. The nanoparticles entered PC12 cells 8 h after treatment, successfully delivering the conjugate compound inside cells. Overall, glycerol monooleate nanoparticles did not exhibit significant toxicity on PC12 cell line in concentrations up to 100 µg/mL, supporting their therapeutic use as drug delivery systems.