Earwax: an innovative tool for assessment of tobacco use or exposure. A pilot study in young adults

Cancer evaluation in dogs using cerumen as a source for volatile biomarker prospection

Cancer is one of the deadliest diseases in humans and dogs. Nevertheless, most tumor types spread faster in canines, and early cancer detection methods are necessary to enhance animal survival. Here, cerumen (earwax) was tested as a source of potential biomarkers for cancer evaluation in dogs. Earwax samples from dogs were collected from tumor-bearing and clinically healthy dogs, followed by Headspace/Gas Chromatography-Mass Spectrometry (HS/GC-MS) analyses and multivariate statistical workflow. An evolutionary-based multivariate algorithm selected 18 out of 128 volatile metabolites as a potential cancer biomarker panel in dogs. The candidate biomarkers showed a full discrimination pattern between tumor-bearing dogs and cancer-free canines with high accuracy in the test dataset: an accuracy of 95.0% (75.1-99.9), and sensitivity and specificity of 100.0% and 92.9%, respectively. In summary, this work raises a new perspective on cancer diagnosis in dogs, being carried out painlessly and non-invasive, facilitating sample collection and periodic application in a veterinary routine.

Development and validation of an ultra-performance liquid chromatography-tandem mass spectrometric method for the determination of 25 psychoactive drugs in cerumen and its application to real postmortem samples

PURPOSE

In the present study, a method for the detection of 25 psychoactive substances in cerumen was developed and validated. This method targets opiates, cocaine, antidepressants, benzodiazepines, antipsychotics and antiparkinsons.

METHODS

Analysis was performed on a SCIEX Triple Quad 6500+ system after liquid-liquid extraction. Methanol with 1% acetic acid was chosen as the extraction solvent. After the addition of the solvent, samples were vortexed, sonicated, centrifuged and directly injected into the liquid chromatography-tandem mass spectrometry system.

RESULTS

The method was found to be selective and sensitive (limit of detection: 0.017 ng-0.33 ng/mg), the assay was linear for all analytes with linear regression coefficient ranging 0.9911-1.00. The values for intra-assay precision was between 4.34 and 14.6% and inter-assay precision between 5.81 and 17.7%, with accuracy within the acceptable criteria for all analytes. All analytes in cerumen specimens were stable for 48 h at 4 °C and 72 h at - 20 °C, whilst no significant matrix effect or carryover was observed. Applicability was proven by analyzing cerumen samples from 25 deceased with a history of drug abuse. All analytes were detected in real samples, thus confirming the sensitivity of the developed method.

CONCLUSIONS

According to our knowledge, it is the first time that a method for the simultaneous detection of 25 psychoactive drugs in cerumen was developed, fully validated and finally applied to 25 postmortem samples.

A cerumenolomic approach to bovine trypanosomosis diagnosis

INTRODUCTION

Trypanosomiasis caused by Trypanosoma vivax (T. vivax, subgenus Duttonella) is a burden disease in bovines that induces losses of billions of dollars in livestock activity worldwide. To control the disease, the first step is identifying the infected animals at early stages. However, convention tools for animal infection detection by T. vivax present some challenges, facilitating the spread of the pathogenesis.

OBJECTIVES

This work aims to develop a new procedure to identify infected bovines by T. vivax using cerumen (earwax) in a volatilomic approach, here named cerumenolomic, which is performed in an easy, quick, accurate, and non-invasive manner.

METHODS

Seventy-eight earwax samples from Brazilian Curraleiro Pé-Duro calves were collected in a longitudinal study protocol during health and inoculated stages. The samples were analyzed using Headspace/Gas Chromatography-Mass Spectrometry followed by multivariate analysis approaches.

RESULTS

The cerumen analyses lead to the identification of a broad spectrum of volatile organic metabolites (VOMs), of which 20 VOMs can discriminate between healthy and infected calves (AUC = 0.991, sensitivity = 0.967, specificity = 1.000). Furthermore, 13 VOMs can indicate a pattern of discrimination between the acute and chronic phases of the T. vivax infection in the animals (AUC = 0.989, sensitivity = 0.944, specificity = 1.000).

CONCLUSION

The cerumen volatile metabolites present alterations in their occurrence during the T.vivax infection, which may lead to identifying the infection in the first weeks of inoculation and discriminating between the acute and chronic phases of the illness. These results may be a breakthrough to avoid the T. vivax outbreak and provide a faster clinical approach to the animal.

Determination of fentanyl and norfentanyl in cerumen in the setting of postmortem investigation

Cerumen is an emerging alternative biological matrix in the field of forensic toxicology. An ultra-high-pressure liquid chromatography-mass spectrometry/mass spectrometry [UHPLC-MS/MS] method for the determination of fentanyl and norfentanyl in cerumen was developed and applied in a mixed drug toxicity fatal case. The method was found to be selective and sensitive (LOQ: 0.05 ng/mg for fentanyl and 0.02 ng/mg for norfentanyl), while validation included recovery, carryover, short-term stability, matrix effect, accuracy, and precision (RSD%). Accuracy ranged from 83.1% to 103.5%, while intra- and inter-day precision ranged from 8.6% to 13.1% and from 8.3% to 15.8%, respectively. Matrix effect experiments showed that matrix did not significantly affect signal intensity (82.3%-96.8%). Short-term stability concerning sample extracts was found satisfactory. Fentanyl and norfentanyl were detected in cerumen at a concentration of 1.17 and 0.36 ng/mg respectively. The findings in cerumen corroborate the cause of death and suggest that cerumen is a potential specimen for detecting drugs of abuse in forensic cases.

Identification of cattle poisoning by Bifenthrin via earwax analysis by HS/GC-MS

The use of pyrethroids has increased over recent years, and corresponds to a higher exposure of animals to pesticide residues in the environment and diet. Here, an outbreak of pyrethroid poisoning in beef cattle was reported occurring in Midwestern Brazil. After veterinary evaluation, it was observed that the bovines presented common pyrethroid intoxication symptoms. Aiming to identify the cattle poising by pyrethroid, earwax samples were collected from two groups: exposed and nonexposed animals from the same farm. Blind earwax analyses of the bovines were carried out using headspace/gas chromatography-mass spectrometry (HS/GC-MS). The HS/GC-MS analysis detected the presence of bifenthrin in the earwax analysis of the exposed animals, confirmed by the comparison of its MS fragments with a bifenthrin standard, and also by its retention time relative to the internal standard. In summary, HS/GC-MS analysis of earwax emerges as a tool that can be used in the detection and monitoring of bifenthrin poisoning in cattle, as a useful veterinary diagnosis that ensures animal health and the safety of their products.

A volatolomic approach using cerumen as biofluid to diagnose bovine intoxication by Stryphnodendron rotundifolium

An innovative volatolomic approach employs the detection of biomarkers present in cerumen (earwax) to identify cattle intoxication by Stryphnodendron rotundifolium Mart., Fabaceae (popularly known as barbatimão). S. rotundifolium is a poisonous plant with the toxic compound undefined and widely distributed throughout the Brazilian territory. Cerumen samples from cattle of two local Brazilian breeds ('Curraleiro Pé-Duro' and 'Pantaneiro') were collected during an experimental intoxication protocol and analyzed using headspace (HS)/GC-MS followed by multivariate analysis (genetic algorithm for a partial least squares, cluster analysis, and classification and regression trees). A total of 106 volatile organic metabolites were identified in the cerumen samples of bovines. The intoxication by S. rotundifolium influenced the cerumen volatolomic profile of the bovines throughout the intoxication protocol. In this way, it was possible to detect biomarkers for cattle intoxication. Among the biomarkers, 2-octyldecanol and 9-tetradecen-1-ol were able to discriminate all samples between intoxicated and nonintoxicated bovines. The cattle intoxication diagnosis by S. rotundifolium was accomplished by applying the cerumen analysis using HS/GC-MS, in an easy, accurate, and noninvasive way. Thus, the proposed bioanalytical chromatography protocol is a useful tool in veterinary applications to determine this kind of intoxication.

Insights into cerumen and application in diagnostics: past, present and future prospective

Cerumen or earwax is an emerging bio-fluid in clinical diagnosis that has been very little exploited during the past decades in spite of its high diagnostic potential. It is highly abundant in diagnostic biomarkers such as genetic material, lipids, proteins, chemical elements, internal and external metabolites (e.g. hormones, volatile organic compounds, amino acids, xenobiotics etc.) reaching earwax from the blood circulation. Thus, it is able to reflect not only physiology, pathophysiology of the human body but can also detect recent and long term exposure to environmental pollutants, without the need of invasive blood tests and in the same time overcoming many disadvantages faced by using other diagnostic biological fluids. This review discusses the biology, functions, chemistry of earwax, past and current approaches for the study of its chemical composition, emphasizing how a detected variation in its composition can offer information of high clinical value, which can be useful in diagnosis of many diseases such as metabolic disorders and tumours as well as in forensic applications. It also presents details about techniques of sample collection, storage, and analysis. Moreover, it highlights concerns about the use of earwax for diagnostic purposes, which should be addressed to make earwax diagnostics a reality in the future.

An Evaluation of Hair, Oral Fluid, Earwax, and Nasal Mucus as Noninvasive Specimens to Determine Livestock Exposure to Teratogenic Lupine Species

The livestock industry in the western United States loses an estimated $500 million annually from livestock production losses due to poisonous plants. Poisoning of livestock by plants often goes undiagnosed because there is a lack of appropriate or available specimens for analysis. The Lupinus species represent an important toxic plant in western North America that can be toxic and/or teratogenic to livestock species due to the quinolizidine alkaloids. The objective of this study was to evaluate the potential of using earwax, hair, oral fluid, and nasal mucus as noninvasive specimens to determine livestock exposure to the teratogenic Lupinus species. Quinolizidine alkaloids were detected in these four matrices in cattle that were administered a single dose of Lupinus leucophyllus. In addition, quinolizidine alkaloids from lupine were detected in the earwax of cattle that grazed on lupine-infested rangelands. This study demonstrates the potential of earwax, hair, oral fluid, and nasal mucus as noninvasive specimens for chemical analyses to aid in the diagnosis of livestock that may have been exposed to and poisoned by plants.

Earwax metabolomics: An innovative pilot metabolic profiling study for assessing metabolic changes in ewes during periparturition period

Important metabolic changes occur during transition period of late pregnancy and early lactation to meet increasing energy demands of the growing fetus and for milk production. The aim of this investigation is to present an innovative and non-invasive tool using ewe earwax sample analysis to assess the metabolic profile in ewes during late pregnancy and early lactation. In this work, earwax samples were collected from 28 healthy Brazilian Santa Inês ewes divided into 3 sub-groups: 9 non-pregnant ewes, 6 pregnant ewes in the last 30 days of gestation, and 13 lactating ewes ≤ 30 days postpartum. Then, a range of metabolites including volatile organic compounds (VOC), amino acids (AA), and minerals were profiled and quantified in the samples by applying headspace gas chromatography/mass spectrometry, high performance liquid chromatography/tandem mass spectrometry, and inductively coupled plasma-optical emission spectrometry, respectively. As evident in our results, significant changes were observed in the metabolite profile of earwax between the studied groups where a remarkable elevation was detected in the levels of non-esterified fatty acids, alcohols, ketones, and hydroxy urea in the VOC profile of samples obtained from pregnant and lactating ewes. Meanwhile, a significant decrease was detected in the levels of 9 minerals and 14 AA including essential AA (leucine, phenyl alanine, lysine, isoleucine, threonine, valine), conditionally essential AA (arginine, glycine, tyrosine, proline, serine), and a non-essential AA (alanine). Multivariate analysis using robust principal component analysis and hierarchical cluster analysis was successfully applied to discriminate the three study groups using the variations of metabolites in the two stress states (pregnancy and lactation) from the healthy non-stress condition. The innovative developed method was successful in evaluating pre- and post-parturient metabolic changes using earwax and can in the future be applied to recognize markers for diagnosis, prevention, and intervention of pregnancy complications in ewes.