Sulfur dioxide, a double-faced molecule in mammals

Air pollution mixture associated with oxidative stress exacerbation and symptoms deterioration in allergic rhinitis patients: Evidence from a panel study

With allergic rhinitis (AR) on the rise globally, there has been a growing focus on the role of environmental pollutants in the onset of AR. However, the potential mechanisms by how and which these pollutants exacerbate AR conditions remain unknown. This panel study of 49 patients diagnosed with AR over one year aimed to assess the individual and combined effects of short-term exposure to multiple ambient pollutants on oxidative stress, symptoms, and quality of life among patients with AR. All participants underwent four repeated assessments of health conditions and personal environmental exposures (PM2.5, O3, SO2, and NO2) over warm and cold seasons during 2017-2018. We evaluated two oxidative stress biomarkers (malondialdehyde [MDA], and superoxide dismutase [SOD]) via nasal lavage. We collected information on self-reported symptoms and quality of life using the Rhinitis Symptom Scale (SRS), the Visual Analog Scale (VAS), and the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) through in-person interviews. Bayesian kernel machine regression (BKMR) was used to evaluate the joint effects of pollutant mixture and identify key contributors. The results revealed a significant association of the pollutant mixture when all four pollutants were at or above their median levels, with increased oxidative stress. This was evidenced by elevated MDA and reduced SOD. We found a joint detrimental effect of the pollutant mixture on AR symptoms with a strong association with increased SRS scores, but a non-significant positive association with VAS and RQLQ scores. PM2.5, O3, and SO2 presented as the potentially primary contributors to the adverse health effects associated with the pollutant mixture in Taiyuan city. Patients with AR exposed to short-term air pollutant mixture are more likely to have greater nasal symptoms and worse quality of life from increased oxidative stress and reduced antioxidant capacity. Further research is warranted to better elucidate the underlying mechanisms.

The effect of air pollution exposure on the risk of outpatient visits for periodontitis: a time-series study

This study aimed to determine if air pollution affected the risk of periodontitis outpatient visits. We collected the records of 56,456 periodontitis outpatient visits in Hefei, China, from January 1, 2014 to December 31, 2021. The relationship between air pollution and periodontitis outpatient visits was evaluated using distributed lag nonlinear and generalized linear models. Additional analyses were performed, stratifying the data by age, season, and sex. Subgroup analyses showed a significantly higher risk of periodontitis outpatient visits due to NO2 exposure during the warm season compared with the cold season. Moreover, O3 exposure was associated with a lower risk of periodontitis outpatient visits in the cold season. The findings suggest that NO2 exposure is associated with an increased risk of periodontitis outpatient visits, whereas O3 exposure is associated with a decreased risk of periodontitis outpatient visits. Season is found to be an effect modifier in these associations.

Repetitive sulfur dioxide exposure in mice models post-deployment respiratory syndrome

Soldiers deployed to Iraq and Afghanistan have a higher prevalence of respiratory symptoms than nondeployed military personnel and some have been shown to have a constellation of findings on lung biopsy termed post-deployment respiratory syndrome (PDRS). Since many of the subjects in this cohort reported exposure to sulfur dioxide (SO2), we developed a model of repetitive exposure to SO2 in mice that phenocopies many aspects of PDRS, including adaptive immune activation, airway wall remodeling, and pulmonary vascular (PV) disease. Although abnormalities in small airways were not sufficient to alter lung mechanics, PV remodeling resulted in the development of pulmonary hypertension and reduced exercise tolerance in SO2-exposed mice. SO2 exposure led to increased formation of isolevuglandins (isoLGs) adducts and superoxide dismutase 2 (SOD2) acetylation in endothelial cells, which were attenuated by treatment with the isoLG scavenger 2-hydroxybenzylamine acetate (2-HOBA). In addition, 2-HOBA treatment or Siruin-3 overexpression in a transgenic mouse model prevented vascular remodeling following SO2 exposure. In summary, our results indicate that repetitive SO2 exposure recapitulates many aspects of PDRS and that oxidative stress appears to mediate PV remodeling in this model. Together, these findings provide new insights regarding the critical mechanisms underlying PDRS.NEW & NOTEWORTHY We developed a mice model of "post-deployment respiratory syndrome" (PDRS), a condition in Veterans with unexplained exertional dyspnea. Our model successfully recapitulates many of the pathological and physiological features of the syndrome, revealing involvement of the ROS-isoLGs-Sirt3-SOD2 pathway in pulmonary vasculature pathology. Our study provides additional knowledge about effects and long-term consequences of sulfur dioxide exposure on the respiratory system, serving as a valuable tool for future PDRS research.

Glutathione-triggered release of SO2 gas to augment oxidative stress for enhanced chemodynamic and sonodynamic therapy

Recently, gas therapy has emerged as a promising alternative treatment for deep-seated tumors. However, some challenges regarding insufficient or uncontrolled gas generation as well as unclear therapeutic mechanisms restrict its further clinical application. Herein, a well-designed nanoreactor based on intracellular glutathione (GSH)-triggered generation of sulfur dioxide (SO2) gas to augment oxidative stress has been developed for synergistic chemodynamic therapy (CDT)/sonodynamic therapy (SDT)/SO2 gas therapy. The nanoreactor (designed as CCM@FH-DNs) is constructed by employing iron-doped hollow mesoporous silica nanoparticles as carriers, the surface of which was modified with the SO2 prodrug 2,4-dinitrobenzenesulfonyl (DNs) and further coated with cancer cell membranes for homologous targeting. The CCM@FH-DNs can not only serve as a Fenton-like agent for CDT, but also as a sonosensitizer for SDT. Importantly, CCM@FH-DNs can release SO2 for SO2-mediated gas therapy. Both in vitro and in vivo evaluations demonstrate that the CCM@FH-DNs nanoreactor performs well in augmenting oxidative stress for SO2 gas therapy-enhanced CDT/SDT via GSH depletion and glutathione peroxidase-4 enzyme deactivation as well as superoxide dismutase inhibition. Moreover, the doped iron ions ensure that the CCM@FH-DNs nanoreactors enable magnetic resonance imaging-guided therapy. Such a GSH-triggered SO2 gas therapy-enhanced CDT/SDT strategy provides an intelligent paradigm for developing efficient tumor microenvironment-responsive treatments.

A Thermally Stable SO2-Releasing Mechanophore: Facile Activation, Single-Event Spectroscopy, and Molecular Dynamic Simulations

Polymers that release small molecules in response to mechanical force are promising candidates as next-generation on-demand delivery systems. Despite advancements in the development of mechanophores for releasing diverse payloads through careful molecular design, the availability of scaffolds capable of discharging biomedically significant cargos in substantial quantities remains scarce. In this report, we detail a nonscissile mechanophore built from an 8-thiabicyclo[3.2.1]octane 8,8-dioxide (TBO) motif that releases one equivalent of sulfur dioxide (SO2) from each repeat unit. The TBO mechanophore exhibits high thermal stability but is activated mechanochemically using solution ultrasonication in either organic solvent or aqueous media with up to 63% efficiency, equating to 206 molecules of SO2 released per 143.3 kDa chain. We quantified the mechanochemical reactivity of TBO by single-molecule force spectroscopy and resolved its single-event activation. The force-coupled rate constant for TBO opening reaches ∼9.0 s-1 at ∼1520 pN, and each reaction of a single TBO domain releases a stored length of ∼0.68 nm. We investigated the mechanism of TBO activation using ab initio steered molecular dynamic simulations and rationalized the observed stereoselectivity. These comprehensive studies of the TBO mechanophore provide a mechanically coupled mechanism of multi-SO2 release from one polymer chain, facilitating the translation of polymer mechanochemistry to potential biomedical applications.

ONOO- Activatable Fluorescent Sulfur Dioxide Donor for a More Accurate Assessment of Cell Ferroptosis

Ferroptosis is critical in the treatment of tumor therapies. Thus, monitoring reactive oxygen species (ROS) is of great significance for accurate assessment in ferroptosis without any interference. However, current probes for monitoring ROS during ferroptosis suffer from a drawback in that the probes consume ROS during detection, which inhibits the ferroptosis process and thus affects the accuracy and effectiveness of monitoring the process of ferroptosis. Herein, a new fluorescent donor probe, TFMU-SO2D, with the combination of the moiety of the SO2 donor is designed and synthesized by introducing the aryl boronate moieties that could give it the ability to effectively recognize ONOO-. The released SO2 could consume excess glutathione and regulate oxidative stress by elevating ROS levels, which would offset the ROS depletion by TFMU-SO2D and ensure accuracy in monitoring the ferroptosis process. The experimental results demonstrated that TFMU-SO2D possessed satisfactory performance for monitoring ONOO- as well as simultaneously releasing SO2 in oxidative stress stimulated by monensin and ferroptosis stimulated by erastin and RSL3. Additionally, the capability of SO2 synergized with ferroptosis to inhibit the viability of cancer cells was demonstrated by the CCK8 assay, which may be due to the fact that SO2 can potentiate ferroptosis cell death by increasing the ROS level. Overall, these combined results indicated that TFMU-SO2D possesses the excellent ability to precisely monitor ONOO- during ferroptosis without interference, which is significant for accurately accessing ferroptosis, cancer treatment, and drug development.

Recent advances in sulfur dioxide releasing nanoplatforms for cancer therapy

Sulfur dioxide (SO2), long considered to be a harmful atmospheric pollutant, has recently been posited as the fourth gasotransmitter, as it is produced endogenously in mammals and has important pathophysiological effects. The field of tumor therapy has witnessed a paradigm shift with the emergence of SO2-based gas therapy. This has been possible because SO2 is a potent glutathione consumer that can promote the production of reactive oxygen species, eventually leading to oxidative-stress-induced cancer cell death. Nevertheless, this therapeutic gas cannot be directly administrated in gaseous form. Thus, various nano formulations incorporating SO2 donors or prodrugs capable of storing and releasing SO2 have been developed in an attempt to achieve active/passive intratumoral accumulation and SO2 release in the tumor microenvironment. In this review article, the advances over the past decade in nanoplatforms incorporating sulfur SO2 prodrugs to provide controlled release of SO2 for cancer therapy are summarized. We first describe the synthesis of polypeptide SO2 prodrugs to overcome multiple drug resistance that was pioneered by our group, followed by other macromolecular SO2 prodrug structures that self-assemble into nanoparticles for tumor therapy. Second, we describe nanoplatforms composed of various small-molecule SO2 donors with endogenous or exogenous stimuli responsiveness, including thiol activated, acid-sensitive, and ultraviolet or near-infrared light-responsive SO2 donors, which have been used for tumor inhibition. Combinations of SO2 gas therapy with photodynamic therapy, chemotherapy, photothermal therapy, sonodynamic therapy, and nanocatalytic tumor therapy are also presented. Finally, we discuss the current limitations and challenges and the future outlook for SO2-based gas therapy. STATEMENT OF SIGNIFICANCE: Gas therapy is attracting increasing attention in the scientific community because it is a highly promising strategy against cancer owing to its inherent biosafety and avoidance of drug resistance. Sulfur dioxide (SO2) is recently found to be produced endogenously in mammals with important pathophysiological effects. This review summarizes recent advances in SO2 releasing nanosystems for cancer therapy, including polymeric prodrugs, endogenous or exogenous stimulus-activated SO2 donors delivered by nanoplatform and combination therapy strategies.

Small molecule probes as versatile energy acceptors: A breakthrough in photoelectrochemical sensing for sulfur dioxide recording in rat brain

Microelectrode-based photoelectrochemical (PEC) sensing is a newly developed and promising analytical technique for in vivo analysis. However, the inadequate specificity in complex environment of living bodies restricted its further in vivo application. Herein, we utilized a small molecule probe as the energy acceptor to quench the photocurrent of CdTe quantum dots through energy transfer. The efficiency of energy transfer was modulated by the concentration of target SO2, resulting in changes in photocurrent. The chemical recognition reaction between small molecule probes and SO2 enhanced the specificity of PEC sensing, thus guaranteeing its in vivo applications. Furthermore, with the use of light addressing strategy, simultaneous detection in the multiple brain regions was implemented. The energy transfer based light addressable PEC microsensor achieved monitoring fluctuations of SO2 levels in multiple brain regions of rats with epilepsy.

Fire and Brimstone: SO2 as a Chemical Weapon in History

Sulfur dioxide (SO2), a chemical produced from the burning of sulfur-containing materials, has a long history in chemical warfare. While it was largely used during ancient sieges, there were numerous proposals to weaponize it for the open battlefield in the early modern age.

Thiol-Responsive Polypeptide Sulfur Dioxide Prodrug Nanoparticles for Effective Tumor Inhibition

Sulfur dioxide (SO2) based gas therapy has emerged as a novel anticancer therapeutic strategy because of its high therapeutic efficacy and biosafety. To precisely adjust the SO2 content and control gas release, herein, a thiol-responsive polypeptide SO2 prodrug mPEG-block-poly(2-amino-6-(2,4-dinitrophenylsulfonamido)hexanoic acid) (PEG-b-PLys-DNs) was designed and facilely synthesized by polymerization of a novel N-carboxyanhydride SO2-NCA. The anticancer potential of the self-assembled nanoparticles (SO2-NPs) was investigated in detail. First, PEG-b-PLys-DNs were synthesized by ring-opening polymerization of SO2-NCA, which self-assembled into NPs sized 88.4 nm in aqueous. Subsequently, SO2-NPs were endocytosed into 4T1 cells and quickly released SO2 under a high concentration of glutathione in tumor cells. This process depleted cellular glutathione, generated reactive oxygen species, and dramatically increased oxidative stress, which led to cancer cell apoptosis. Finally, the in vivo anticancer efficacy of SO2-NPs was verified in 4T1-tumor-bearing mice. Our results indicated that this novel SO2 polymeric prodrug has great potential in eradicating tumors.

Association between ambient air pollutant interaction with kidney function in a large Taiwanese population study

The associations and interactions between kidney function and other air pollutants remain poorly defined. Therefore, the aim of this study was to evaluate associations among air pollutants, including particulate matter (PM) with a diameter ≤ 2.5 μm (PM_2.5), PM₁₀ (PM with a diameter ≤ 10 μm), carbon monoxide (CO), nitrogen oxide (NO), nitrogen oxides (NO_x), sulfur dioxide (SO₂), and ozone (O₃) with kidney function, and explore interactions among these air pollutants on kidney function. We used the Taiwan Air Quality Monitoring and Taiwan Biobank databases to derive data on community-dwelling individuals in Taiwan and daily air pollution levels, respectively. We enrolled 26,032 participants. Multivariable analysis showed that high levels of PM_2.5, PM₁₀, O₃ (all p < 0.001), and SO₂ (p = 0.001) and low levels of CO, NO (both p < 0.001), and NO_x (p = 0.047) were significantly correlated with low estimated glomerular filtration rate (eGFR). With regard to negative effects, the interactions between PM_2.5 and PM₁₀ (p < 0.001), PM_2.5 and PM₁₀ (p < 0.001), PM_2.5 and SO₂, PM₁₀ and O₃ (both p = 0.025), PM₁₀ and SO₂ (p = 0.001), and O₃ and SO₂ (p < 0.001) on eGFR were significantly negatively. High PM₁₀, PM_2.5, O₃, and SO₂ were associated with a low eGFR, whereas high CO, NO, and NO_x were associated with a high eGFR. Furthermore, negative interactions between PM_2.5 and PM₁₀, O₃ and SO₂, PM₁₀ and O₃, PM_2.5 and SO₂, and PM₁₀ and SO₂ on eGFR were observed. The findings of this study have important implications for public health and environmental policy. Specifically, the results of this study may be useful in individuals and organizations to take action to reduce air pollution and promote public health.

Association between ambient air pollutants and upper respiratory tract infection and pneumonia disease burden in Thailand from 2000 to 2022: a high frequency ecological analysis

BACKGROUND

A pertinent risk factor of upper respiratory tract infections (URTIs) and pneumonia is the exposure to major ambient air pollutants, with short term exposures to different air pollutants being shown to exacerbate several respiratory conditions.

METHODS

Here, using disease surveillance data comprising of reported disease case counts at the province level, high frequency ambient air pollutant and climate data in Thailand, we delineated the association between ambient air pollution and URTI/Pneumonia burden in Thailand from 2000 - 2022. We developed mixed-data sampling methods and estimation strategies to account for the high frequency nature of ambient air pollutant concentration data. This was used to evaluate the effects past concentrations of fine particulate matter (PM_2.5), sulphur dioxide (SO₂), and carbon monoxide (CO) and the number of disease case count, after controlling for the confounding meteorological and disease factors.

RESULTS

Across provinces, we found that past increases in CO, SO_2, and PM_2.5 concentration were associated to changes in URTI and pneumonia case counts, but the direction of their association mixed. The contributive burden of past ambient air pollutants on contemporaneous disease burden was also found to be larger than meteorological factors, and comparable to that of disease related factors.

CONCLUSIONS

By developing a novel statistical methodology, we prevented subjective variable selection and discretization bias to detect associations, and provided a robust estimate on the effect of ambient air pollutants on URTI and pneumonia burden over a large spatial scale.

Repetitive Sulfur Dioxide Exposure in Mice Models Post-Deployment Respiratory Syndrome

Soldiers deployed to Iraq and Afghanistan have a higher prevalence of respiratory symptoms than non-deployed military personnel and some have been shown to have a constellation of findings on lung biopsy termed post-deployment respiratory syndrome (PDRS). Since many of the deployers in this cohort reported exposure to sulfur dioxide (SO 2 ), we developed a model of repetitive exposure to SO 2 in mice that phenocopies many aspects of PDRS, including adaptive immune activation, airway wall remodeling, and pulmonary vascular disease (PVD). Although abnormalities in small airways were not sufficient to alter lung mechanics, PVD was associated with the development of pulmonary hypertension and reduced exercise tolerance in SO 2 exposed mice. Further, we used pharmacologic and genetic approaches to demonstrate a critical role for oxidative stress and isolevuglandins in mediating PVD in this model. In summary, our results indicate that repetitive SO 2 exposure recapitulates many aspects of PDRS and that oxidative stress may mediate PVD in this model, which may be helpful for future mechanistic studies examining the relationship between inhaled irritants, PVD, and PDRS.

Association between air pollutants with calcaneus ultrasound T-score change in a large Taiwanese population follow-up study

Exposure to ambient air pollution has been associated with increased rates of mortality and morbidity and a shorter life expectancy. Few studies have evaluated the associations between air pollution and change in calcaneus ultrasound T-score (∆T-score). Therefore, in this longitudinal study, we explored these associations in a large group of Taiwanese participants. We used data from the Taiwan Biobank database and Taiwan Air Quality Monitoring Database, which contains detailed daily data on air pollution. We identified 27,033 participants in the Taiwan Biobank database who had both baseline and follow-up data. The median follow-up period was 4 years. The studied ambient air pollutants included particulates of 2.5 μm or less (PM_2.5), particulates of 10 μm or less (PM₁₀), ozone (O₃), carbon monoxide (CO), sulfur dioxide (SO₂), nitric oxide (NO), nitrogen dioxide (NO₂), and nitrogen oxide (NO_x). Multivariable analysis showed that PM_2.5 (β, -0.003; 95% confidence interval (CI), -0.004 to -0.001; p < 0.001), PM₁₀ (β, -0.005; 95% CI, -0.006 to -0.004, p < 0.001), O₃ (β, -0.008; 95% CI, -0.011 to -0.004; p < 0.001), and SO₂ (β, -0.036; 95% CI, -0.052 to -0.020; p < 0.001) were negatively associated with ∆T-score, and that CO (β, 0.344; 95% CI, 0.254, 0.433; p < 0.001), NO (β, 0.011; 95% CI, 0.008 to 0.015; p < 0.001), NO₂ (β, 0.011; 95% CI, 0.008 to 0.014; p < 0.001), and NO_x (β, 0.007; 95% CI, 0.005 to 0.009; p < 0.001) were positively significantly associated with ∆T-score. Furthermore, PM_2.5 and SO₂ (β, -0.014; 95% CI, -0.016 to -0.013; p < 0.001) and PM₁₀ and SO₂ (β, -0.008; 95% CI, -0.009 to -0.007; p < 0.001) had synergistic negative effects on ∆T-score. In conclusion, we found that high PM_2.5, PM₁₀, O₃, and SO₂ were associated with a rapid decline in T-score, whereas high CO, NO, NO₂, and NO_x were associated with a slow decline in T-score. Furthermore, PM_2.5 and SO₂ and PM₁₀ and SO₂ had synergistic negative effects on ∆T-score, causing an acceleration in T-score decline. These findings may be helpful when developing policies on air pollution regulation.

The Role of Gasotransmitter-Dependent Signaling Mechanisms in Apoptotic Cell Death in Cardiovascular, Rheumatic, Kidney, and Neurodegenerative Diseases and Mental Disorders

Cardiovascular, rheumatic, kidney, and neurodegenerative diseases and mental disorders are a common cause of deterioration in the quality of life up to severe disability and death worldwide. Many pathological conditions, including this group of diseases, are based on increased cell death through apoptosis. It is known that this process is associated with signaling pathways controlled by a group of gaseous signaling molecules called gasotransmitters. They are unique messengers that can control the process of apoptosis at different stages of its implementation. However, their role in the regulation of apoptotic signaling in these pathological conditions is often controversial and not completely clear. This review analyzes the role of nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H₂S), and sulfur dioxide (SO₂) in apoptotic cell death in cardiovascular, rheumatic, kidney, and neurodegenerative diseases. The signaling processes involved in apoptosis in schizophrenia, bipolar, depressive, and anxiety disorders are also considered. The role of gasotransmitters in apoptosis in these diseases is largely determined by cell specificity and concentration. NO has the greatest dualism; scales are more prone to apoptosis. At the same time, CO, H₂S, and SO₂ are more involved in cytoprotective processes.

Interactive effects of meteorological factors and air pollutants on hand, foot, and mouth disease in Chengdu, China: a time-series study

OBJECTIVES

Hand, foot, and mouth disease (HFMD) is a viral infectious disease that poses a substantial threat in the Asia-Pacific region. It is widely reported that meteorological factors are associated with HFMD. However, the relationships between air pollutants and HFMD are still controversial. In addition, the interactive effects between meteorological factors and air pollutants on HFMD remain unknown. To fill this research gap, we conducted a time-series study.

DESIGN

A time-series study.

SETTING AND PARTICIPANTS

Daily cases of HFMD as well as meteorological and air pollution data were collected in Chengdu from 2011 to 2017. A total of 184 610 HFMD cases under the age of 15 were included in our study.

OUTCOME MEASURES

Distributed lag nonlinear models were used to investigate the relationships between HFMD and environmental factors, including mean temperature, relative humidity, SO₂, NO₂, and PM₁₀. Then, the relative excess risk due to interaction (RERI) and the proportion attributable to interaction were calculated to quantitatively evaluate the interactions between meteorological factors and air pollutants on HFMD. Bivariate response surface models were used to visually display the interactive effects.

RESULTS

The cumulative exposure-response curves of SO₂ and NO₂ were inverted 'V'-shaped and 'M'-shaped, respectively, and the risk of HFMD gradually decreased with increasing PM₁₀ concentrations. We found that there were synergistic interactions between mean temperature and SO₂, relative humidity and SO₂, as well as relative humidity and PM₁₀ on HFMD, with individual RERIs of 0.334 (95% CI 0.119 to 0.548), 0.428 (95% CI 0.214 to 0.642) and 0.501 (95% CI 0.262 to 0.741), respectively, indicating that the effects of SO₂ and PM₁₀ on HFMD were stronger under high temperature (>17.3°C) or high humidity (>80.0%) conditions.

CONCLUSIONS

There were interactive effects between meteorological factors and air pollutants on HFMD. Our findings could provide guidance for targeted and timely preventive and control measures for HFMD.

Chain-shattering polymeric sulfur dioxide prodrug micelles for redox-triggered gas therapy of osteosarcoma

Sulfur dioxide (SO₂) based gas therapy has received great attention recently. Nevertheless, it is still a challenge to fabricate a SO₂ delivery system to achieve effective delivery and on-demand stimuli triggered release at tumor sites. Herein, a chain-shattering polymeric SO₂ prodrug micelle system was fabricated for effective SO₂ based gas therapy. First, an amphiphilic polymer (mPEG-P(HDI-DN)) was prepared by polycondensation of poly(ethylene glycol) methyl ether, hexamethylene diisocyanate and monomer containing SO₂. mPEG-P(HDI-DN) can self-assemble into spherical micelles with a diameter of around 50-90 nm. Triggered release of SO₂ from micelles can be achieved in the presence of GSH with the degradation of mPEG-P(HDI-DN) into small molecules. The in vitro experiment proved that mPEG-P(HDI-DN) micelles can enter into osteosarcoma cells and inhibit the growth of osteosarcoma cells by increasing the ROS level in cells. The in vivo experiments demonstrate that mPEG-P(HDI-DN) micelles can inhibit the growth of osteosarcoma effectively without obvious tissue toxicity. These results indicate that this chain-shattering polymeric SO₂ prodrug micelle system is a promising candidate for effective SO₂ based gas therapy.

Short-term effect of sulfur dioxide (SO2) change on the risk of tuberculosis outpatient visits in 16 cities of Anhui Province, China: the first multi-city study to explore differences in occupational patients

A growing number of biological studies suggest that exogenous sulfur dioxide (SO₂) at a certain concentration may promote human resistance to Mycobacterium tuberculosis. However, the results of most relevant studies are inconsistent, and few studies have explored the relationship between SO₂ exposure and tuberculosis risk at provincial level. In addition, occupational exposure has long been considered to have a certain impact on the human body, so for the first time, we discussed the differences between different occupations in the study on the relationship between air pollutant exposure and tuberculosis risk, and evaluated the impact of occupational exposure. This study aimed to explore the association between short-term SO₂ exposure and the risk of outpatient visits to tuberculosis in Anhui province and 16 prefecture-level cities from 2015 to 2020. We used several models for multi-stage analysis, including distributed lag nonlinear model (DLNM), Poisson generalized linear regression model, and random-effects model. The association was assessed using the 28-day cumulative lag effect RR and 95%CI for each 10-unit increase in SO₂ concentration. We divided all patients into the following six occupations: Worker, Farmer, Retired people, Children and Students, Cadre and Office clerk, and Service staff (catering, business, etc.). Sex, age, and season were analyzed by subgroup. Finally, the robustness of the multi-pollutant model was tested. At provincial level, the overall effect value of SO₂ was RR=0.8191 (95%CI: 07702~0.8712); after grouping all patients by occupation, the association found only among Farmers (RR = 0.7150, 95%CI: 0.6699-0.7632, lag 0-28 days) and Workers (RR = 0.8566, 95%CI: 0.7930-0.9930, lag 0-4 days) was still statistically significant. Estimates for individual cities and using random-effects models to estimate average associations showed that SO₂ exposure was associated with a reduced risk of outpatient TB visits in 14 municipalities, which remained significant when aggregated (RR = 0.9030, 95%CI: 0.8730-0.9340). Analysis of patients grouped by occupation in each municipality showed that statistical significance was again observed only in the Farmer (RR = 0.8880, 95%CI: 0.8610-0.9160) and Worker (RR = 0.8250, 95%CI: 0.7290-0.9340) groups. Stratified analysis of age, sex, and season showed that the effect of SO₂ exposure was greater for middle-aged people (18-64 years old) and males, and less for seasonal changes. In summary, we found that exposure to SO₂ reduces the risk of outpatient visits to tuberculosis, with farmers and workers more susceptible to SO₂. Gender and age had a greater impact on the risk of TB outpatient visits than seasonal variations.

Association between maternal exposure to gaseous pollutants and atrial septal defect in China: A nationwide population-based study

BACKGROUND

The association between maternal exposure to gaseous air pollutants and congenital heart defects (CHD) remains unclear. The concentration-response relationship and the time windows of susceptibility to gaseous pollutants may vary by pollutant species and CHD subtypes.

OBJECTIVE

We aimed to examine the relationship between maternal exposures to four species of gaseous pollutants (NO₂, O₃, SO₂, and CO) and atrial septal defect (ASD), which is a common subtype of CHD, and to determine the critical time windows of susceptibility for each gaseous pollutant.

METHODS

Among 1,253,633 infants born between October 1, 2013 and December 31, 2016 in China, 1937 newborns were diagnosed with isolated ASD, a prevalence of 1.55‰. Maternal exposures to the gaseous pollutants were estimated by matching the geocoded maternal addresses with the gridded ambient concentrations. The adjusted odds ratios (aOR) between exposures and ASD were quantified by using mixed-effects logistic regression models.

RESULTS

We found significantly positive associations between ASD and maternal exposures to NO₂, O₃, SO₂, and CO during entire pregnancy, first-, second-, and third-trimester. However, no statistically significant association was found between maternal exposure to PM_2.5, PM_2.5-10 and ASD risk (P > 0.05). In the fully adjusted model with respect to average exposure over entire pregnancy, the adjusted odds ratios (aOR) for each 10 μg/m³ increment of NO₂, O₃, SO₂ were 1.33 (95% CI: 1.22-1.45), 1.13 (95% CI: 1.10-1.16), 1.28 (95% CI: 1.20-1.35), respectively; the aOR for each 100 μg/m³ increment of CO was 1.10 (95% CI: 1.06-1.15). The observed concentration-response relationships varied by exposure periods and pollutants, with the strongest association for NO₂ during the 1st-8th embryology weeks, for O₃ during the third trimester, for SO₂ during the second trimester, and for CO without obvious variation.

CONCLUSIONS

The findings suggest an increased risk of ASD in association with maternal exposures to four common gaseous pollutants. From the perspective of birth defects prevention and ASD risk mitigation, it is critical to reduce maternal exposure to gaseous pollutants especially during the most susceptible time windows.

Environmental Air Pollutants Inhaled during Pregnancy Are Associated with Altered Cord Blood Immune Cell Profiles

Air pollution exposure during pregnancy may be a risk factor for altered immune maturation in the offspring. We investigated the association between ambient air pollutants during pregnancy and cell populations in cord blood from babies born to mothers with asthma enrolled in the Breathing for Life Trial. For each patient (n = 91), daily mean ambient air pollutant levels were extracted during their entire pregnancy for sulfur dioxide (SO₂), nitric oxide, nitrogen dioxide, carbon monoxide, ozone, particulate matter <10 μm (PM₁₀) or <2.5 μm (PM_2.5), humidity, and temperature. Ninety-one cord blood samples were collected, stained, and assessed using fluorescence-activated cell sorting (FACS). Principal Component (PC) analyses of both air pollutants and cell types with linear regression were employed to define associations. Considering risk factors and correlations between PCs, only one PC from air pollutants and two from cell types were statistically significant. PCs from air pollutants were characterized by higher PM_2.5 and lower SO₂ levels. PCs from cell types were characterized by high numbers of CD8 T cells, low numbers of CD4 T cells, and by high numbers of plasmacytoid dendritic cells (pDC) and low numbers of myeloid DCs (mDCs). PM_2.5 levels during pregnancy were significantly associated with high numbers of pDCs (p = 0.006), and SO₂ with high numbers of CD8 T cells (p = 0.002) and low numbers of CD4 T cells (p = 0.011) and mDCs (p = 4.43 × 10⁻⁶) in cord blood. These data suggest that ambient SO₂ and PM_2.5 exposure are associated with shifts in cord blood cell types that are known to play significant roles in inflammatory respiratory disease in childhood.

Semen quality and windows of susceptibility: A case study during COVID-19 outbreak in China

BACKGROUND

To evaluate the impact of air pollution exposure on semen quality parameters during COVID-19 outbreak in China, and to identify potential windows of susceptibility for semen quality.

METHODS

A retrospective observational study was carried out on 1991 semen samples collected between November 23, 2019 and July 23, 2020 (a period covering COVID-19 lock-down in China) from 781 sperm donor candidates at University-affiliated Sichuan Provincial Human Sperm Bank. Multivariate mixed-effects regression models were constructed to investigate the relationship between pollution exposure, windows of susceptibility, and semen quality, while controlling for biographic and meteorologic confounders.

RESULT(S)

The results indicated multiple windows of susceptibility for semen quality, especially sperm motility, due to ambient pollution exposure. Exposure to particulate matters (PM_2.5 and PM₁₀), O₃ and NO₂ during late stages of spermatogenesis appeared to have weak but positive association with semen quality. Exposure to CO late in sperm development appeared to have inverse relationship with sperm movement parameters. Exposure to SO₂ appeared to influence semen quality throughout spermatogenesis.

CONCLUSION(S)

Potential windows of susceptibility for semen quality varied depending on air pollutants. Sperm motility was sensitive to pollution exposure. Findings from current study further elucidate the importance of sensitive periods during spermatogenesis and provide new evidence for the determinants of male fertility.

FRET Modulated Signaling: A Versatile Strategy to Construct Photoelectrochemical Microsensors for In Vivo Analysis

Microelectrode-based electrochemical (EC) and photoelectrochemical (PEC) sensors are promising candidates for in vivo analysis of biologically important chemicals. However, limited selectivity in complicated biological systems and poor adaptability to electrochemically non-active species restrained their applications. Herein, we propose the concept of modulating the PEC output by a fluorescence resonance energy transfer (FRET) process. The emission of energy donor was dependent on the concentration of target SO₂ , which in turn served as the modulator of the photocurrent signal of the photoactive material. The employment of optical modulation circumvented the problem of selectivity, and the as-fabricated PEC microelectrode showed good stability and reproducibility in vivo. It can monitor fluctuations of SO₂ levels in brains of rat models of cerebral ischemia-reperfusion and febrile seizure. More significantly, such a FRET modulated signaling strategy can be extended to diverse analytes.

Nanomedicines for combating multidrug resistance of cancer

Chemotherapy typically involves the use of specific chemodrugs to inhibit the proliferation of cancer cells, but the frequent emergence of a variety of multidrug-resistant cancer cells poses a tremendous threat to our combat against cancer. The fundamental causes of multidrug resistance (MDR) have been studied for decades, and can be generally classified into two types: one is associated with the activation of diverse drug efflux pumps, which are responsible for translocating intracellular drug molecules out of the cells; the other is linked with some non-efflux pump-related mechanisms, such as antiapoptotic defense, enhanced DNA repair ability, and powerful antioxidant systems. To overcome MDR, intense efforts have been made to develop synergistic therapeutic strategies by introducing MDR inhibitors or combining chemotherapy with other therapeutic modalities, such as phototherapy, gene therapy, and gas therapy, in the hope that the drug-resistant cells can be sensitized toward chemotherapeutics. In particular, nanotechnology-based drug delivery platforms have shown the potential to integrate multiple therapeutic agents into one system. In this review, the focus was on the recent development of nanostrategies aiming to enhance the efficiency of chemotherapy and overcome the MDR of cancer in a synergistic manner. Different combinatorial strategies are introduced in detail and the advantages as well as underlying mechanisms of why these strategies can counteract MDR are discussed. This review is expected to shed new light on the design of advanced nanomedicines from the angle of materials and to deepen our understanding of MDR for the development of more effective anticancer strategies. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

SO2 derivatives induce dysfunction in human trophoblasts via inhibiting ROS/IL-6/STAT3 pathway

BACKGROUND

Epidemiological studies have revealed that sulfur dioxides (SO₂) can increase the risk of pregnancy complications such as missed abortion in the first trimester, stillbirth, preterm birth, small for gestational age, gestational diabetes mellitus and preeclampsia, but the mechanisms underlying these findings remains unknown. What is known, however, is that trophoblasts, a type of fetal cell exerting vital immunologic functions to maintain a successful pregnancy, are usually involved in the pathogenic mechanism of pregnancy complications.

OBJECTIVE

To study the effect of SO₂ derivatives (bisulfite and sulfite, 1:3 M/M) on the function of trophoblasts.

METHODS

Swan.71 trophoblast cells were treated with various concentrations of SO₂ derivatives to determine the effect of SO₂ derivatives on cellular viability by CKK8. Flow cytometry was performed to analyze the effect of SO₂ derivatives on apoptosis, cell cycle and intracellular ROS. Wound healing assay and transwell assay were conducted to examine the migration and invasion of Swan.71 cells. Inflammation-related cytokines in the supernatant (IL-1β, IL-6, IL-8, IL-10 and TNF-α) were measured by IMMULITE®1000 Systems (SIEMENS). The expression level of NLRP3, Caspase1, MMP9, MMP2, STAT3, and p-STAT3 were evaluated by Western Blotting.

RESULTS

Exposure to SO₂ derivatives significantly decreased cellular viability, arrested cell cycle at S/G2/M phase and induced cell apoptosis of Swan.71 trophoblasts. In addition, the migration and invasion of Swan.71 cell were significantly inhibited. SO₂ derivatives also significantly increased IL-1β secretion while it is NLRP3/Caspase1 independent. IL-6 secretion was significant inhibited accompanied by decreased STAT3 phosphorylation and expression of MMP2 and MMP9. The intracellular ROS level was significantly suppressed by SO₂ derivatives.

CONCLUSION

SO₂ derivatives exert toxic effects on trophoblasts which results in: suppressing cellular viability and intracellular ROS level, interfering with cell proliferation through arresting cell cycle, inducing cell apoptosis, disturbing inflammation-related cytokines secretion and inhibiting motility. Decreased ROS/IL-6/STAT3 levels play a role in inhibited cell viability, cell cycle arrest, apoptosis and defective motility.

A novel fluorescent probe for rapid detection of sulfur dioxide in living cells

Sulfur dioxide is one of the reactive sulfur species, which has significant physiological functions in cells. Some physiological processes are closely related to SO₂ in organisms, and the high concentration of SO₂ in living cells can cause many diseases. In order to investigate the unique function of SO₂ at the subcellular level, developing a molecular tool which could detect of SO₂ within organelles is imperative. Hence, we developed a cationic dye named HQ-SO₂ as a new fluorescent probe to specifically monitor SO₂ , which was easy to obtain through one-step reaction. It took Michael addition reaction as the mechanism of reaction for detection of SO₂ . In addition, this probe showed a series of highly favorable properties such as rapid response rate, low cytotoxicity, high selectivity, low detection limit, and good photostability, which enabled the probe to track SO₂ in living cells.

A Rare Presentation of Acquired Laryngomalacia and Tracheomalacia in a Child Associated with Apricot Sulfurization

Sulfur fumigation has come to replace traditional sun drying methods for drying fruits over the years around the world as it is a cheaper and faster method because of its pesticidal and anti-bacterial properties. We report the case of an 11-year-old boy with acquired severe biphasic stridor who was exposed to extremely high concentrations of sulfur dioxide (SO2) during apricot sulfurization processes with his mother. The patient's bronchoscopy revealed severe glottic and subglottic damage. Exposure to SO2 is a health risk, particularly for individuals who are sulfide-sensitive, especially in childhood. The pulmonary epithelium may be directly injured by inhaled toxic substances at various levels of the respiratory system. To the best of our knowledge, this is the first case reported of acquired airway damage associated with sulfurization in a pediatric patient without a known history of any respiratory disease or symptoms.

A ratiometric fluorescent probe for the rapid and specific detection of HSO3 - in water samples

Hydrosulphite (HSO₃ ^- ), as a common and important chemical reagent, is widely used in everyday life, however excessive use and abuse of HSO₃ ^- can cause potential harmful effects on the environment and in biological health. In this paper, we describe the design and preparation of a colorimetric and ratiometric fluorescence probe for the visual detection of HSO₃ ^- (excitation wavelengths were, respectively, 336 nm and 520 nm). This method showed some advantages including simple preparation, high selectivity, fast response, and significant colour and fluorescence ratio (F₄₅₀ /F₅₉₄ ) changes in the presence of HSO₃ ^- . In addition, this probe was used successfully for the detection of HSO₃ ^- in real water samples and showed a good recovery rate range.

Mercapto-responsive polymeric nano-carrier capable of releasing sulfur dioxide

This article reports platform to prepare polymeric nano-carriers capable of releasing SO₂ and hydrophobic payloads upon triggering by mercapto-containing species.

Air Pollutants Interaction and Gender Difference on Bone Mineral Density T-Score in Taiwanese Adults

Osteoporosis is defined as a systemic skeletal disease characterized by a reduction in bone mass and microarchitectural deterioration of bone tissue. Previous studies have reported associations between air pollution and lower bone mineral density; however, few studies have investigated the association between air pollution and osteoporosis. In this study, we combined two databases, the first including 5000 individuals registered in the Taiwan Biobank, and the second containing detailed daily data on air pollution. After multivariable adjustments, ozone (O3) (unstandardized coefficient β, 0.015; p = 0.008) was significantly positively associated with T-score, whereas carbon monoxide (CO) (unstandardized coefficient β, -0.809; p < 0.001), sulfur dioxide (SO2) (unstandardized coefficient β, -0.050; p = 0.005), nitric oxide (NO) (unstandardized coefficient β, -0.040; p < 0.001), nitrogen dioxide (NO2) (unstandardized coefficient β, -0.023; p < 0.001), and nitrogen oxide (NOx) (unstandardized coefficient β, -0.017; p < 0.001) were significantly negatively associated with T-score. The interactions between CO and NOx (p = 0.001) and SO2 and NO2 (p = 0.004) on T-score were statistically significant. An increase in exposure to CO, NO and NOx was associated with a faster decline in T-score in the female participants compared to the male participants. In addition, an increase in O3 was associated with a faster increase in T-score in the female participants compared to the male participants. In conclusion, the air pollutants CO, SO2, NO, NO2, and NOx were associated with osteoporosis. In addition, there were interaction and synergetic effects between CO and NOx and SO2 and NO2 on T-score. We also observed differences in the associations between air pollutants and T-score between the female and male participants.

Reduction-responsive sulfur dioxide polymer prodrug nanoparticles loaded with irinotecan for combination osteosarcoma therapy

Combination therapy can boost the therapeutic effectiveness of monotherapies by achieving synergy between therapeutic agents. Herein, a reduction-responsive sulfur dioxide (SO₂) polymer prodrug was synthesized as a nanocarrier to load irinotecan (IRN) to be used in combination osteosarcoma therapy. The SO₂ prodrug (denoted as mPEG-PLG (DNs)) was synthesized by coupling a small-molecule SO₂ donor, N-(3-azidopropyl)-2,4-dinitrobenzenesulfonamide (AP-DNs), to the side chains of methoxy poly (ethylene glycol)-block-poly (γ-propargyl-_L-glutamate) block copolymer. The mPEG-PLG (DNs) had the ability to self-assemble into micelles while simultaneously encapsulating IRN in aqueous media. The formed micelles led to enhanced SO₂ and IRN release in reductive conditions. Using nile red as a model drug, the loaded micelles were efficiently internalized by cancer cells, demonstrated by confocal laser scanning microscopy and flow cytometry. The release of SO₂ within nanoparticles (NPs) in tumor cells led to enhanced intracellular reactive oxygen species amounts together with induced oxidative destruction to cancer cells. Furthermore, the IRN-loaded SO₂ polymer prodrug NPs mediated synergistic therapeutic effects against osteosarcoma cells, leading to improved biodistribution and enhanced tumor growth inhibition over control groups in a murine osteosarcoma model. Taken together, this work highlights the potential of SO₂ polymer prodrugs as reduction-responsive nanocarriers to load chemotherapeutics for effective combination osteosarcoma therapy.

An AIE probe for imaging mitochondrial SO2-induced stress and SO2 levels during heat stroke

A probe, MITO-TPE, was developed for imaging mitochondrial SO₂ with good selectivity, high sensitivity, and a fast response time. Cell imaging indicated that SO₂-induced oxidative stress may cause damage to cells through O₂˙^- bursting. MITO-TPE has here been used to image the misregulation of SO₂ levels in mitochondria during heat stroke for the first time.

Sulfur dioxide derivatives produce antidepressant- and anxiolytic-like effects in mice

Sulfur dioxide (SO₂) can be endogenously generated from sulfur-containing amino acids in animals and humans. Increasing evidence shows that endogenous SO₂ may act as a gaseous molecule to participate in many physiological and pathological processes. However, the role of SO₂ and its derivatives in the central nervous system remains poorly understood. The present study explored the protective effects of exogenous SO₂ derivatives (Na₂SO₃:NaHSO₃, 3:1 M/M) on cellular injury in vitro by using the cell proliferation assay (MTS), cell counting kit 8 assay (CCK-8), and cyto-flow assay in the corticosterone (CORT)-induced PC12 cell injury model. We also examined the antidepressant and anxiolytic effects of SO₂ derivatives on the chronic mild stress (CMS)-induced depression mouse model by using the open field test, novelty suppressed feeding test, forced swimming test, tail suspension test, and sucrose preference test. In the MTS and CCK-8 assays, we found that preexposure of SO₂ derivatives significantly blocked CORT-induced decrease of cellular survival without causing any negative effects. Results from the cyto-flow assay indicated that treatment with SO₂ derivatives could reverse CORT-induced early and late apoptosis of PC12 cells. Systemic treatment with SO₂ derivatives produced markedly antidepressant- and anxiolytic-like activities in mice under normal condition and rapidly reversed CMS-induced depressive- and anxiety-like behaviors. In conclusion, these findings indicate that exogenous SO₂ derivatives show protective properties against the detrimental effects of stress and exert antidepressant- and anxiolytic-like actions. The present study suggests that exogenous SO₂ derivatives are potential therapeutic agents for the treatment of depression, anxiety, and other stress-related diseases.

Azithromycin ameliorates sulfur dioxide-induced airway epithelial damage and inflammatory responses

Background

The airway epithelium (AE) forms the first line of defence against harmful particles and pathogens. Barrier failure of the airway epithelium contributes to exacerbations of a range of lung diseases that are commonly treated with Azithromycin (AZM). In addition to its anti-bacterial function, AZM has immunomodulatory effects which are proposed to contribute to its clinical effectiveness. In vitro studies have shown the AE barrier-enhancing effects of AZM. The aim of this study was to analyze whether AE damage caused by inhalation of sulfur dioxide (SO₂) in a murine model could be reduced by pre-treatment with AZM.

Methods

The leakiness of the AE barrier was evaluated after SO₂ exposure by measuring levels of human serum albumin (HSA) in bronchoalveolar lavage fluid (BALF). Protein composition in BALF was also assessed and lung tissues were evaluated across treatments using histology and gene expression analysis.

Results

AZM pre-treatment (2 mg/kg p.o. 5 times/week for 2 weeks) resulted in reduced glutathione-S-transferases in BALF of SO₂ injured mice compared to control (without AZM treatment). AZM treated mice had increased intracellular vacuolization including lamellar bodies and a reduction in epithelial shedding after injury in addition to a dampened SO₂-induced inflammatory response.

Conclusions

Using a mouse model of AE barrier dysfunction we provide evidence for the protective effects of AZM in vivo, possibly through stabilizing the intracellular microenvironment and reducing inflammatory responses. Our data provide insight into the mechanisms contributing to the efficacy of AZM in the treatment of airway diseases.

Associations between the incidence and mortality rates of type 2 diabetes mellitus and long-term exposure to ambient air pollution: A 12-year cohort study in northern China

BACKGROUND

Ambient air pollution has recently been related to type 2 diabetes mellitus (T2DM), a disease that has caused an economic and health burden worldwide. Evidence of an association between air pollution and T2DM was reported in the United States and Europe. However, few studies have focused on the association with high levels of air pollutants in a developing country.

OBJECTIVES

We conducted a 12-year cohort study to assess the incidence and mortality of T2DM associated with long-term exposure to PM₁₀, SO₂, and NO₂.

METHODS

A retrospective cohort with participants from four cities in northern China was conducted to assess mortality and incidence of T2DM from 1998 to 2009. Incidence of T2DM was self-reported, and incident intake of an antidiabetic drug or injection of insulin simultaneously and mortality of T2DM was obtained from a family member and double checked against death certificates provided from the local center for disease control and prevention. Individual pollution exposures were the mean concentrations of pollutants estimated from the local environmental monitoring centers over the survival years. Hazard ratios (HRs) were estimated using Cox regression models after adjusting for potential confounding factors.

RESULTS

A total of 39 054 participants were recruited into the mortality cohort, among which 59 subjects died from T2DM; 38 529 participants were analyzed in the incidence cohort, and 1213 developed new cases of T2DM. For each 10 μg/m³ increase in PM₁₀, SO₂, and NO₂, the adjusted HRs and 95% confidence interval (CI) for diabetic incidence were 1.831 (1.778, 1.886), 1.287 (1.256, 1.318), and 1.472 (1.419, 1.528), respectively. Similar results can be observed in the analysis of diabetic mortality with HRs (95% CI) up to 2.260 (1.732, 2.950), 1.130 (1.042, 1.225), and 1.525 (1.280, 1.816), respectively.

CONCLUSIONS

Our results suggested that long-term exposure to high levels of PM₁₀, SO₂, and NO₂ increase risk of incident and mortality of T2DM in China.

Association between long-term exposure to Sulfur dioxide pollution and hypertension incidence in northern China: a 12-year cohort study

Several studies have researched the short-term effect of sulfur dioxide (SO₂) exposure on hypertension. However, no evidence has provided the relationship between long-term high pollution exposure of SO₂ and morbidity of hypertension in cohort studies in China. This retrospective cohort study aimed to evaluate this association. We used Cox proportional hazards regression models to examine the hazard ratios (HR) for hypertension risks from 1998 to 2009 associated with accumulative exposure of air SO₂ among adults in northern China. Annual average concentrations of sulfur dioxide (SO₂) were obtained from 15 local environmental monitoring centers. Hypertension was identified according to self-reported diagnostic time and treatment for hypertension with anti-hypertensive medication. Among 37,386 participants, 2619 new cases of hypertension were identified during 426,334 person-years. In the fully adjusted model, HR and 95% confidence interval (CI) of hypertension incidence for each 10 μg/m³ increase in SO₂ were 1.176 (1.163 and 1.189). Results from stratified analyses suggested that effects of SO₂ on hypertension morbidity were more pronounced in participants < 60 years old, tea drinkers, and those with high education, high poultry consumption, and active (occasional and frequent) exercise. We found that long-term exposure to high levels of SO₂ increased the risk of incidence of hypertension in China.

A bond energy transfer based difunctional fluorescent sensor for Cys and bisulfite

In living cells, cysteine (Cys) and bisulfite are involved in many important physiological processes. Their unbalance in vivo would lead to multiple diseases. So, it is vital to develop difuntional sensor for Cys and bisulfite. As we known, cysteine could metabolized into bisulfite by the metabolic processes of cysteine in the animal level. Therefore, we designed and synthesized a mitochondria-targeted long-wavelength ratio fluorescence sensor Z2 for Cys and bisulfite simultaneous detection. Z2 exhibitted excellent selectivity, good anti-interference, fast response and low detection limit. The sensor exhibited obviously two channels fluorescence response for Cys and bisulfite orderly. Z2 is widely used for imaging Cys and bisulfite in MCF-7 cells, zebrafish, and mice, and successfully imaging Cys metabolism in these livings. We hope this bifunctional ratio fluorescence sensor Z2 will be a useful tool to monitor Cys and SO₂ levels in living systems.

GSH-triggered release of sulfur dioxide gas to regulate redox balance for enhanced photodynamic therapy

Herein, a promising strategy is explored to regulate redox balance in tumor cells by simultaneously consuming GSH and releasing SO₂ gas for enhanced photodynamic therapy.

A mitochondrion-targeted dual-site fluorescent probe for the discriminative detection of SO32− and HSO3− in living HepG-2 cells

Sulfur dioxide, known as an environmental pollutant, produced during industrial productions is also a common food additive that is permitted worldwide. In living organisms, sulfur dioxide forms hydrates of sulfite (SO₂·H₂O), bisulfite (HSO₃⁻) and sulfite (SO₃²⁻) under physiological pH conditions; these three exist in a dynamic balance and play a role in maintaining redox balance, further participating in a wide range of physiological and pathological processes. On the basis of the differences in nucleophilicity between SO₃²⁻ and HSO₃⁻, for the first time, we built a mitochondrion-targeted dual-site fluorescent probe (Mito-CDTH-CHO) based on benzopyran for the highly specific detection of SO₃²⁻ and HSO₃⁻ with two diverse emission channels. Mito-CDTH-CHO can discriminatively respond to the levels of HSO₃⁻ and SO₃²⁻. Besides, its advantages of low cytotoxicity, superior biocompatibility and excellent mitochondrial enrichment ability contribute to the detection and observation of the distribution of sulfur dioxide derivatives in living organisms as well as allowing further studies on the physiological functions of sulfur dioxide.

Rational design and sensing mechanism of a dual-site fluorescence probe for HSO₃⁻ and SO₃²⁻.

pH/glutathione-responsive release of SO2 induced superoxide radical accumulation for gas therapy of cancer

A pH/glutathione (GSH)-responsive SO₂ generation nanoplatform (BODS NPs) is established to achieve lysosomal escape and GSH depletion in tumors to sensitize the SO₂-mediated oxidative stress.

Small-molecule fluorescent probes for specific detection and imaging of chemical species inside lysosomes

In the past few years, the preparation of novel small-molecule fluorescent probes for specific detection and imaging of chemical species inside lysosomes has attracted considerable attention because of their wide applications in chemistry, biology, and medical science. This feature article summarizes the recent advances in the design and preparation of small-molecule fluorescent probes for specific detection of chemical species inside lysosomes. In addition, their properties and applications for the detection and imaging of pH, H2O2, HOCl, O2˙-, lipid peroxidation, H2S, HSO3-, thiols, NO, ONOO-, HNO, Zn2+, Cu2+, enzymes, etc. in lysosomes are discussed as well.

Arsenic and sulfur dioxide co-exposure induce renal injury via activation of the NF-κB and caspase signaling pathway

Although emerging evidence suggests positive association of arsenic (As) or sulfur dioxide (SO₂) exposure with human diseases, reports concerning the effects of co-exposure of As and SO₂ are lacking. Moreover, there is insufficient information in the literature about As and SO₂ co-exposure to renal injury. In this study, we focus on the environmental problems of excessive As and SO₂ that co-exist in many coal consumption areas. We used both C57BL/6 mice and 293T cells to detect toxicities of As and SO₂ exposure alone or in combination. Our results showed that co-exposure significantly increased the hazard compared with exposure to As or SO₂ alone. Mouse kidney tissue slices showed that co-exposure caused more severe diffuse sclerosing glomerulonephritis than As and SO₂ exposure alone. Meanwhile experiments showed that apoptosis was aggravated by co-exposure of As and SO₂ in 293T cells. Because As and SO₂ cause cell toxicity through increasing oxidative stress, next we detected ROS and other oxidative stress parameters, and the results showed oxidative stress was increased by co-exposure compared with the other three groups. The expression levels of downstream genes in the NF-κB and caspase pathways were higher in the co-exposure group than in the groups of As or SO₂ exposure alone in mice and 293T cells. Based on the above results, co-exposure could induce higher toxicity in vitro and in vivo compared with single exposure to As or SO₂, indicating that people living in places that contaminated by As and SO₂ may have higher chance to get renal injury.

Vive la Difference! The Effects of Natural and Conventional Wines on Blood Alcohol Concentrations: A Randomized, Triple-Blind, Controlled Study

Different alcoholic beverages can have different effects on blood alcohol concentration (BAC) and neurotoxicity, even when equalized for alcohol content by volume. Anecdotal evidence suggested that natural wine is metabolized differently from conventional wines. This triple-blind study compared the BAC of 55 healthy male subjects after consuming the equivalent of 2 units of alcohol of a natural or conventional wine over 3 min in two separate sessions, one week apart. BAC was measured using a professional breathalyzer every 20 min after consumption for 2 h. The BAC curves in response to the two wines diverged significantly at twenty minutes (interval T20) and forty minutes (interval T40), and also at their maximum concentrations (peaks), with the natural wine inducing a lower BAC than the conventional wine [T20 = 0.40 versus 0.46 (p < 0.0002); T40 = 0.49 versus 0.53 (p < 0.0015); peak = 0.52 versus 0.56 (p < 0.0002)]. These differences are likely related to the development of different amino acids and antioxidants in the two wines during their production. This may in turn affect the kinetics of alcohol absorption and metabolism. Other contributing factors could include pesticide residues, differences in dry extract content, and the use of indigenous or selected yeasts. The study shows that with the same quantity and conditions of intake, natural wine has lower pharmacokinetic and metabolic effects than conventional wine, which can be assumed due to the different agronomic and oenological practices with which they are produced. It can therefore be hypothesized that the consumption of natural wine may have a different impact on human health from that of conventional wine.

Efficient synthesis of 3-sulfolenes from allylic alcohols and 1,3-dienes enabled by sodium metabisulfite as a sulfur dioxide equivalent

We present herein an efficient and practical method for a gram scale synthesis of 3-sulfolenes using sodium metabisulfite as a safe, inexpensive, and easy to handle sulfur dioxide equivalent. Diversely-substituted 3-sulfolenes can be prepared by reacting a variety of 1,3-dienes or allylic alcohols with sodium metabisulfite in aqueous hexafluoroisopropanol (HFIP) or in aqueous methanol in the presence of potassium hydrogen sulfate. Advantageously, the method enables conversion of allylic alcohols directly to 3-sulfolenes, bypassing intermediate 1,3-dienes.

Gas-Generating Nanoplatforms: Material Chemistry, Multifunctionality, and Gas Therapy

The fast advances of theranostic nanomedicine enable the rational design and construction of diverse functional nanoplatforms for versatile biomedical applications, among which gas-generating nanoplatforms (GGNs) have emerged very recently as unique theranostic nanoplatforms for broad gas therapies. Here, the recent developments of the rational design and chemical construction of versatile GGNs for efficient gas therapies by either exogenous physical triggers or endogenous disease-environment responsiveness are reviewed. These gases involve some therapeutic gases that can directly change disease status, such as oxygen (O₂ ), nitric oxide (NO), carbon monoxide (CO), hydrogen (H₂ ), hydrogen sulfide (H₂ S) and sulfur dioxide (SO₂ ), and other gases such as carbon dioxide (CO₂ ), dl-menthol (DLM), and gaseous perfluorocarbon (PFC) for supplementary assistance of the theranostic process. Abundant nanocarriers have been adopted for gas delivery into lesions, including poly(d,l-lactic-co-glycolic acid), micelles, silica/mesoporous silica, organosilica, MnO₂ , graphene, Bi₂ Se₃ , upconversion nanoparticles, CaCO₃ , etc. Especially, these GGNs have been successfully developed for versatile biomedical applications, including diagnostic imaging and therapeutic use. The biosafety issue, challenges faced, and future developments on the rational construction of GGNs are also discussed for further promotion of their clinical translation to benefit patients.