Cross-reactivity between halogenated platinum salts in an immediate-type respiratory hypersensitivity model

Induction of cell death by sodium hexachloroplatinate (IV) in the HEI-OC1 cell line, primary rat spiral ganglion cells and rat organ of Corti explants

Although cochlear implants have become a well-established method for patients with sensory neural hearing loss, clinical results indicate that in some cases, corrosion of electrode contacts leads to high impedance that interferes with successful stimulation of the auditory nerve. As it is unclear whether corrosion products induce cell damage, we focused on cell culture models of the organ of Corti cell line (HEI-OC1), rat spiral ganglion cells (SGC) and rat organ of Corti explant (OCex) cultivated from neonatal rat cochleae to characterize the cytotoxicity of sodium hexachloroplatinate (IV) (Na2(PtCl6)). The oxidative activity in HEI-OC1 cells decreased with increasing Na2(PtCl6) concentrations between 8 and 16 ng/μl, and live cell staining with Calcein acetoxymethyl/Ethidium homodimer III revealed an increasing number of cells with disrupted membranes. Ultrastructural evidence of mitophagy followed by necroptosis was detected. Additionally, exposure of the SGC to 15-35 ng/μl Na2(PtCl6) dose-dependently reduced neuronal survival and neuritogenesis, as determined by neurofilament antigen staining. In parallel, staining glial cells and fibroblasts with specific antibodies confirmed the dose-dependent induction of cell death by Na2(PtCl6). Exposure of the OCex to 25-45 ng/μl Na2(PtCl6) resulted in severe concentration-dependent hair cell loss. Our data show for the first time that Na2(PtCl6) induces cell death in a concentration-dependent manner in inner ear cell types and tissues.

Update on occupational allergy, including asthma, to soluble platinum salts

PURPOSE OF REVIEW

This review aims to evaluate recent literature on occupational platinum salt exposure and allergy and asthma in the context of existing evidence.

RECENT FINDINGS

A major recent development is that large quantitative platinum salt exposure datasets have become available and are finding applications in epidemiological studies. These exposure data are expected to lead to higher quality epidemiological studies focusing on exposure response relations, modifiers of exposure and sensitization risk. The exposure data might also improve medical referral advice as part of medical surveillance studies and contribute to improved evidence on the effectiveness of exposure referral.

SUMMARY

Hopefully, the availability of exposure databases form a stimulus for more exposure response studies and risk assessments leading to science based primary prevention approaches. The availability of more detailed exposure data can guide job transfer decisions in occupational clinical practice.

Exposure to soluble platinum salts in precious metal refinery workers over a 17-year period

BACKGROUND

Occupational exposure to soluble chlorinated platinum (Pt) salts, commonly called chloroplatinates, is a known cause of Pt salt sensitisation (PSS) and occupational asthma. We aimed to model inhalable soluble Pt salts exposure levels based on measurements in precious metal refineries for use in a retrospective cohort study on PSS.

METHODS

Five platinum refineries located in the United Kingdom (3 sites), United States, and South Africa provided time weighted average inhalable soluble Pt salts exposure data, measured in 2,982 personal air samples over a 17-year period (2000-2016). We used a Bayesian hierarchical model to estimate geometric mean (GM) exposure levels for each refinery and job title over time.

RESULTS

The GM of measured exposure levels over all facilities was 92 ng/m3 with a geometric standard deviation (GSD) of 9.07. Facility-specific GMs ranged from 48 ng/m3 (GSD 15.3) to 242 ng/m3 (GSD 5.99). Exposure modelling showed that soluble Pt salts exposure levels declined approximately 10% per year in two of the five facilities, but there were no clear time trends in the other facilities. A priori specified exposure groups captured most of the between-jobs differences, which helps to accurately predict exposures for jobs with no measurement data available.

CONCLUSIONS

We applied exposure modelling to estimate time, refinery, and job-specific soluble Pt salts exposures. A significant annual decline in exposure levels was observed in two of the five participating facilities. Modelled exposure levels can be linked to individual workers' job history for exposure-response analysis of PSS in an epidemiological study.

Occupational Exposure to Metals and Solvents: Allergy and Airway Diseases

PURPOSE OF REVIEW

Occupational allergic diseases (OAD) such as occupational contact dermatitis (OCD), occupational asthma (OA), and occupational rhinitis (OR) are the most prevalent occupational diseases in industrialized countries. The purpose of this review is to provide an update about the main occupational metal and solvent exposures related to allergy and airway diseases and to discuss newly defined causative agents and industries in this field.

RECENT FINDINGS

Currently for over 400 causative agents for OA and OCD, several hundreds of agents for OR have been identified. Although many studies have reported an overall decline in OAD related to known agents after implementation of efficient and effective workplace preventive measures, the constant development of new products continuously introduces to the market potential unknown respiratory hazards. Workplace allergens are often high molecular weight (HMW) agents that are > 10 kDa molecular weight and capable of eliciting IgE sensitization. Sensitizing low molecular weight (LMW) agents are often reactive chemicals. Metals and solvents are two large causative agent groups related to OADs that mainly behave as LMW (< 10 kDa) sensitizers and/or irritants. Avoidance of causative exposures through control strategies is the primary prevention approach for OADs. These strategies must be applied and covered for all known and newly defined causative agents. This review aims to summarize current status of known occupational metal and solvent exposures related to allergy and airway diseases and to discuss newly defined causative agents and industries in this field.

Physiological responses to cisplatin using a mouse hypersensitivity model

Background: The physiological mechanisms underlying the development of respiratory hypersensitivity to cisplatin (CDDP) are not well-understood. It has been suggested that these reactions are likely the result of type I hypersensitivity, but other explanations are plausible and the potential for CDDP to induce type I hypersensitivity responses has not been directly evaluated in an animal model. Objectives and Methods: To investigate CDDP hypersensitivity, mice were topically sensitized through application of CDDP before being challenged by oropharyngeal aspiration (OPA) with CDDP. Before and immediately after OPA challenge, pulmonary responses were assessed using whole body plethysmography (WBP). Results: CDDP did not induce an immediate response or alter the respiratory rate in sensitized mice. Two days later, baseline enhanced pause (Penh) values were significantly elevated (p < 0.05) in mice challenged with CDDP. When challenged with methacholine (Mch) aerosol, Penh values were significantly elevated (p < 0.05) in sensitized mice and respiratory rate was reduced (p < 0.05). Lymph node cell counts and immunoglobulin E levels also indicated successful sensitization to CDDP. Irrespective of the sensitization state of the mice, the number of neutrophils increased significantly in bronchoalveolar lavage fluid (BALF) following CDDP challenge. BALF from sensitized mice also contained 2.46 (±0.8) × 10⁴ eosinophils compared to less than 0.48 (±0.2) × 10⁴ cells in non-sensitized mice (p < 0.05). Conclusions: The results from this study indicate that dermal exposure to CDDP induces immunological changes consistent with type I hypersensitivity and that a single respiratory challenge is enough to trigger pulmonary responses in dermally sensitized mice. These data provide previously unknown insights into the mechanisms of CDDP hypersensitivity.