Determination of thiocyanate as a biomarker of tobacco smoke constituents in selected biological materials of human origin

Associations of Perchlorate, Nitrate, and Thiocyanate with Bone Mineral Density in the US General Population: A Multi-Cycle Study of NHANES 2011-2018

BACKGROUND

Perchlorate, nitrate, and thiocyanate are widely recognized as endocrine disrupting chemicals, which are closely related to thyroid function. Animal and human studies show a correlation between thyroid hormone and bone mineral density (BMD). However, it remains unknown whether perchlorate, nitrate, and thiocyanate were associated with BMD. This study aimed to explore the association between perchlorate, nitrate, and thiocyanate exposure with BMD.

METHOD

A cross-sectional analysis among 5607 participants from the 2011-2018 National Health and Nutrition Examination Survey (NHANES) was conducted in the present study. Perchlorate, nitrate, and thiocyanate were detected in urine by ion chromatography. Survey-weighted generalized linear regression, restricted cubic splines, and qgcomp models were used to assess the association of BMDs with single and mixed perchlorate, nitrate, and thiocyanate exposures. In addition, age, gender, and BMI stratified these associations.

RESULTS

Negative associations were found between perchlorate and nitrate with BMDs. Furthermore, based on the qgcomp model results, the combined association of perchlorate, nitrate, and thiocyanate exposure was negatively associated with BMDs (β = -0.017, 95% CI: -0.041, -0.024 for total BMD; β = -0.017, 95% CI: -0.029, -0.005 for lumbar BMD). Additionally, there was a significant effect after gender, age, and BMI stratification between perchlorate, nitrate, and thiocyanate with BMDs in the normal weight group (β = -0.015, 95% CI: -0.020, -0.011 for total BMD; β = -0.022, 95% CI: -0.028, -0.016 for lumbar BMD) and children and adolescents group (β = -0.025, 95% CI: -0.031, -0.019 for total BMD; β -0.017, 95% CI: -0.029, -0.005 for lumbar BMD).

CONCLUSIONS

The present study indicated a negative correlation between BMDs and urinary perchlorate, nitrate, and thiocyanate levels, with nitrate being the main contributor to the mixture effect. People with normal weight and children and adolescents were more likely to be affected.

Environmental perchlorate, thiocyanate, and nitrate exposures and bone mineral density: a national cross-sectional study in the US adults

Associations of perchlorate, thiocyanate, and nitrate exposures with bone mineral density (BMD) in adults have not previously been studied. This study aimed to estimate the associations of individual and concurrent exposure of the three chemicals with adult BMD. Based on National Health and Nutrition Examination Survey (NHANES, 2011-2018), 1618 non-pregnant adults (age ≥ 20 years and 47.0% female) were included in this study. Survey-weighted linear regression models were used to estimate individual urinary perchlorate, thiocyanate, and nitrate concentrations with lumbar spine BMD and total BMD in adults. Then, weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) models were conducted to evaluate associations of co-occurrence of the three chemicals with adult BMD. In all participants, nitrate exposure was inversely associated with lumbar spine BMD (β =  - 0.054, 95%CI: - 0.097, - 0.010). In stratification analyses, significant inverse associations were observed in female and participants older than 40 years old. In WQS regressions, significant negative associations of the weighted sum of the three chemicals with total and lumbar spine BMD (β =  - 0.014, 95%CI: - 0.021, - 0.007; β =  - 0.011, 95%CI: - 0.019, - 0.004, respectively) were found, and the dominant contributor was nitrate. In the BKMR models, non-linear dose-response associations of nitrate exposure with lumbar spine and total BMD were observed. These findings suggested that environmental perchlorate, thiocyanate, and nitrate exposure may reduce adult BMD and nitrate is the main contributor.

Simultaneous determination of cyanide and thiocyanate in milk by GC-MS/MS using cetyltrimethylammonium bromide as both phase transfer catalyst and protein precipitant

A method was developed for simultaneous determination of cyanide and thiocyanate in milk by gas chromatography-tandem quadrupole mass spectrometry (GC-MS/MS). Cyanide and thiocyanate were derivatized with pentafluorobenzyl bromide (PFBBr) as PFB-CN and PFB-SCN, respectively. Cetyltrimethylammonium bromide (CTAB) was employed both as a phase transfer catalyst and a protein precipitant in the sample pretreatment, which facilitates the separation of the organic and aqueous phases, and greatly simplifies the pretreatment procedures to achieve simultaneous and rapid determination of cyanide and thiocyanate. Under the optimized conditions, the limits of detection (LODs) of cyanide and thiocyanate in milk were 0.006 mg/kg and 0.015 mg/kg, and the spiked recoveries ranged from 90.1% to 98.2% and from 91.8% to 98.9% with relative standard deviations (RSDs) less than 18.9% and 15.2%, respectively. The proposed method was validated as a simple, fast and highly sensitive method for the determination of cyanide and thiocyanate in milk.

Association between environmental exposure to perchlorate, nitrate, and thiocyanate and serum α-Klotho levels among adults from the National Health and nutrition examination survey (2007–2014)

Background & aims

Aging is a pathophysiological process driven by a diverse set of complex biological processes, and environmental pollution plays an important role in this process. This study aimed to explore the association between serum α-Klotho levels and urinary perchlorate, nitrate, and thiocyanate levels.

Methods

This secondary dataset analysis included 4875 participants (mean age, 57.69 year; male, 49.58%; non-Hispanic White, 47.67%) from the US National Health and Nutrition Examination Survey (2007–2014). Enzyme-linked immunosorbent assay was used to quantify α-Klotho levels, and ion chromatography coupled with electrospray tandem mass spectrometry was used to quantify thiocyanate, nitrate, and perchlorate levels. Multivariate linear regression models were applied to estimate the association between perchlorate, nitrate, and thiocyanate levels and serum α-Klotho levels.

Results

Urinary thiocyanate levels were negatively associated with α-Klotho levels (β = − 0.006; 95% confidence interval, − 0.010 to − 0.003; P = 0.0004) after adjusting for age, sex, body mass index, race, alcohol consumption, estimated glomerular filtration rate, underlying disease, physical activity, smoking status, usual energy intake, and urinary creatinine and serum cotinine levels and mutual adjustment of urinary perchlorate, urinary nitrate, and urinary thiocyanate levels. The α-Klotho level in participants in the highest quartile was higher by 50.567 ng/mL (β = 50.567; 95% confidence interval, 14.407 to 86.726; P = 0.009) than that in participants in the lowest quartile of urinary perchlorate. A linear relationship was observed between urinary thiocyanate and α-Klotho levels.

Conclusions

Urinary thiocyanate levels were negatively associated with serum α-Klotho levels. Urinary thiocyanate should be further investigated as a potential mediator of aging and age-related diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03444-2.

Recent advances in nanomaterials-based optical sensors for detection of various biomarkers (inorganic species, organic and biomolecules)

This review briefly emphasizes the different detection approaches (electrochemical sensors, chemiluminescence, surface-enhanced Raman scattering), functional nanostructure materials (quantum dots, metal nanoparticles, metal nanoclusters, magnetic nanomaterials, metal oxide nanoparticles, polymer-based nanomaterials, and carbonaceous nanomaterials) and detection mechanisms. Further, this review emphasis on the integration of functional nanomaterials with optical spectroscopic techniques for the identification of various biomarkers (nucleic acids, glucose, uric acid, oxytocin, dopamine, ascorbic acid, bilirubin, spermine, serotonin, thiocyanate, Pb²⁺ , Cu²⁺ , Hg²⁺ , F^- , peptides, and cancer biomarkers (mucin 1, prostate specific antigen, carcinoembryonic antigen, CA15-3, human epidermal growth factor receptor 2, C-reactive protein, and interleukin-6). Analytical characteristics of nanomaterials-based optical sensors are summarized in Tables, providing the insights of nanomaterials-based optical sensors for biomarkers detection. Finally, the opportunities and challenges of nanomaterials-based optical analytical approaches for the detection of various biomarkers (inorganic, organic, biomolecules, peptides and proteins) are discussed.

Antimicrobial Activity of Films and Coatings Containing Lactoperoxidase System: A Review

The production of safe and healthy foodstuffs is considered as one of the most important challenges in the food industry, and achieving this important goal is impossible without using various processes and preservatives. However, recently, there has been a growing concern about the use of chemical preservatives and attention has been focused on minimal process and/or free of chemical preservatives in food products. Therefore, researchers and food manufacturers have been induced to utilize natural-based preservatives such as antimicrobial enzymes in their production. Lactoperoxidase, as an example of antimicrobial enzymes, is the second most abundant natural enzyme in the milk and due to its wide range of antibacterial activities, it could be potentially applied as a natural preservative in various food products. On the other hand, due to the diffusion of lactoperoxidase into the whole food matrix and its interaction and/or neutralization with food components, the direct use of lactoperoxidase in food can sometimes be restricted. In this regard, lactoperoxidase can be used as a part of packaging material, especially edible and coating, to keep its antimicrobial properties to extend food shelf-life and food safety maintenance. Therefore, this study aims to review various antimicrobial enzymes and introduce lactoperoxidase as a natural antimicrobial enzyme, its antimicrobial properties, and its functionality in combination with an edible film to extend the shelf-life of food products.

Oral peroxidases: From antimicrobial agents to ecological actors (Review)

Sialoperoxidase and myeloperoxidase are the two main peroxidase enzymes found in the oral cavity. Sialoperoxidase is present in salivary secretions and in the biofilms that line the oral surfaces, while myeloperoxidase is abundant in the dento-gingival sulcus area. In the presence of hydrogen peroxide (H₂O₂), oral peroxidases catalyze the oxidation of the pseudohalide anion thiocyanate (SCN⁻) to hypothiocyanite (OSCN⁻), a strong oxidant that serves an antimicrobial role. Furthermore, oral peroxidases consume bacteria-produced H₂O₂ and could help inactivate toxic carcinogenic and genotoxic substances. Numerous in vitro studies have reported the antibacterial, antimycotic and antiviral role of peroxidases, suggesting possible applications in oral therapy. However, the use of oral hygiene products incorporating peroxidase systems has not yet been shown to be beneficial for the treatment or prevention of oral infections. This paradox reflects our incomplete knowledge of the physiological role of peroxidases in a complex environment, such as the oral region. While hygiene is crucial for restoring oral microbiota to a symbiotic state, there are no data to suggest that the addition of a peroxidase per se can create a dysbiotic state. Recent investigations have associated the presence of peroxidase activity with gram-positive cocci microbial flora, and its insufficiency with dysbiosis has been linked to pathologies, such as caries, periodontitis or infections of the oral mucosa. Therefore, oxidants generated by oral peroxidases appear to be an essential ecological determinant for oral health through the selection of a symbiotic microbiota capable of resisting oxidative stress. The objective of the present review was to update the current knowledge of the physiological aspects and applications of oral peroxidases in clinical practice.

How to identify a smoker: a salient crystallographic approach to detect thiocyanate content

There is an increasing demand for monitoring environmental pollutants and the control requires new sensing materials with better sensitivity, selectivity and reliability. In this study, a series of Co₇ clusters incorporating various flexible polyhydroxyamine ligands are explored, with the first report of thiocyanate recognition triggered by crystal formation using a Co₇ crystal (1). For this, we have fortunately synthesized three new mixed metal Co₇ clusters with fascinating structural features. The clusters were characterized by spectroscopic and single crystal X-ray diffraction methods and later by DFT calculations. Due to its better emission spectrum, 1 was further utilized for evaluating its sensing ability towards various anions in water. Surprisingly, 1 shows better quenching ability towards the recognition of SCN⁻ with a better binding constant. The luminescence quenching towards SCN⁻ detection was further verified by the single crystal method, HSAB principle (symbiosis) and theoretical calculations such as DFT studies. The SCXRD data clearly suggest that the Co₇ (1) can be converted into Co₁₄ (1a) by direct reaction with NaSCN under ambient conditions. Besides the soft/hard acid–base concept (symbiosis), the energies of formation, and Co–NCS and Co–OH₂ bond energies (as unravelled by DFT) are responsible for this transformation. Therefore, 1 can be used as a selective and sensitive sensor for the detection of thiocyanate anions based on the fluorescence amplification and quenching method. Further, the designed cluster has also been utilized to detect anions in human blood samples to differentiate a smoker and a non-smoker. It has been concluded that the samples of smokers have a high degree of thiocyanate (∼12 or 9.5 mg L⁻¹) in comparison to those of non-smokers (2–3 mg L⁻¹). Thus, this kind of cluster material has high potentiality in the field of bio-medical science in future endeavours for identification of the extent of thiocyanate content in smokers.

A new Co based sensor for thiocyanate recognition by formation of the dimeric crystals is designed to distinguish a smoker from a non-smoker.

Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review

Environmental tobacco smoke exposure (ETS) and smoking have been described as the most prevalent factors in the development of certain diseases worldwide. According to the World Health Organization, more than 8 million people die every year due to exposure to tobacco, around 7 million due to direct ETS and the remaining due to exposure to second-hand smoke. Both active and second-hand exposure can be measured and controlled using specific biomarkers of tobacco and its derivatives, allowing the development of more efficient public health policies. Exposure to these compounds can be measured using different methods (involving for instance liquid- or gas-chromatographic procedures) in a wide range of biological specimens to estimate the type and degree of tobacco exposure. In recent years, a lot of research has been carried out using different extraction methods and different analytical equipment; this way, liquid-liquid extraction, solid-phase extraction or even miniaturized procedures have been used, followed by chromatographic analysis coupled mainly to mass spectrometric detection. Through this type of methodologies, second-hand smokers can be distinguished from active smokers, and this is also valid for e-cigarettes and vapers, among others, using their specific biomarkers. This review will focus on recent developments in the determination of tobacco smoke biomarkers, including nicotine and other tobacco alkaloids, specific nitrosamines, polycyclic aromatic hydrocarbons, etc. The methods for their detection will be discussed in detail, as well as the potential use of threshold values to distinguish between types of exposure.

Xanthine oxidase-lactoperoxidase system and innate immunity: Biochemical actions and physiological roles

The innate immune system in mammals is the first-line defense that plays an important protective role against a wide spectrum of pathogens, especially during early life before the adaptive immune system develops. The enzymes xanthine oxidase (XO) and lactoperoxidase (LPO) are widely distributed in mammalian tissues and secretions, and have a variety of biological functions including in innate immunity, provoking much interest for both in vitro and in vivo applications. The enzymes are characterized by their generation of reactive oxygen and nitrogen species, including hydrogen peroxide, hypothiocyanite, nitric oxide, and peroxynitrite. XO is a major generator of hydrogen peroxide and superoxide that subsequently trigger a cascade of oxidative radical pathways, including those produced by LPO, which have bactericidal and bacteriostatic effects against pathogens including opportunistic bacteria. In addition to their role in host microbial defense, reactive oxygen and nitrogen species play important physiological roles as second messenger cell signaling molecules, including cellular proliferation, differentiation and gene expression. There are several indications that the reactive species generated by peroxide have positive effects on human health, particularly in neonates; however, some important in vivo aspects of this system remain obscure. The primary dependence of the system on hydrogen peroxide has led us to propose it is particularly relevant to neonate mammals during milk feeding.

The Significance of Lactoperoxidase System in Oral Health: Application and Efficacy in Oral Hygiene Products

Lactoperoxidase (LPO) present in saliva are an important element of the nonspecific immune response involved in maintaining oral health. The main role of this enzyme is to oxidize salivary thiocyanate ions (SCN^-) in the presence of hydrogen peroxide (H₂O₂) to products that exhibit antimicrobial activity. LPO derived from bovine milk has found an application in food, cosmetics, and medical industries due to its structural and functional similarity to the human enzyme. Oral hygiene products enriched with the LPO system constitute an alternative to the classic fluoride caries prophylaxis. This review describes the physiological role of human salivary lactoperoxidase and compares the results of clinical trials and in vitro studies of LPO alone and complex dentifrices enriched with bovine LPO. The role of reactivators and inhibitors of LPO is discussed together with the possibility of using nanoparticles to increase the stabilization and activity of this enzyme.

Application of ion chromatography with pulsed amperometric detection for the determination of trace cyanide in biological samples, including breast milk

Cyanide (CN) is the biomarker of exposure to the components of tobacco smoke, although its presence in biological samples is also due to the consumption of products containing cyanogenic glycosides. In this work, we determine the concentration of the free cyanide in urine, saliva and breast milk matrices, using ion chromatography with pulsed amperometric detection (IC-PAD). IC-PAD is an emerging method, with only few documented applications in urine and saliva, and the presented determination in breast milk is its first published report for any method. The biological samples, which were obtained from women staying in a maternity ward, showed cyanide concentrations spanning 1.82-98.47 μg L^-1. Under the optimized chromatographic conditions, the IC-PAD system exhibited satisfactory repeatability (R < 3%, n = 3) and good linearity in the range of 1-100 μg L^-1. Thus, it proved to be an effective tool for monitoring trace cyanide concentration in a series of human body fluid matrices, including breast milk. This last matrix is especially important due to the possible effect on infant health related to the mothers' smoking habits.

Silicon Quantum Dot-Based Fluorescent Probe: Synthesis Characterization and Recognition of Thiocyanate in Human Blood

Allylamine-functionalized silicon quantum dots (ASQDs) of high photostability are synthesized by a robust inverse micelle method to use the material as a fluorescent probe for selective recognition of thiocyanate (a biomarker of a smoker and a nonsmoker). The synthesized ASQDs were characterized by absorption, emission, and Fourier transform infrared spectroscopy. Surface morphology is studied by transmission electron microscopy and dynamic light scattering. The synthesized material exhibits desirable fluorescence behavior with a high quantum yield. A selective and accurate (up to 10-10 M) method of sensing of thiocyanate anion is developed based on fluorescence amplification and quenching of ASQDs. The sensing mechanism is investigated and interpreted with a crystal clear mechanistic approach through the modified Stern-Volmer plot. The developed material and the method is applied to recognize the anion in the human blood sample for identification of the degree of smoking. The material deserves high potentiality in the field of bio-medical science.