Survival of formalin intoxication in a 13-year-old Thoroughbred gelding

BACKGROUND

Formalin intoxication via the gastrointestinal route has not been previously reported in the horse. Whereas ingestion of formalin in humans, although rare, is well documented. Majority of human cases are either accidental, suicidal or homicidal and often lead to fatality, with a reported lethal formaldehyde dose equating to 0.12 - 0.16 g/kg bwt.

OBJECTIVES

To describe a single case report of the clinical management of an adult horse referred to a veterinary teaching hospital following accidental administration of 10% formalin via nasogastric tube.

METHODS

A 13-year-old Thoroughbred gelding originally presented to the referring veterinarian for colic where 1.8 L of 10% formalin was accidentally administered instead of mineral oil via nasogastric intubation, a potentially lethal dose of formaldehyde (0.12 g/kg bwt). Approximately 20-hours following 10% formalin administration the horse was admitted to the referral hospital with moderate tachycardia, occasional ectopic beats, tacky and hyperaemic mucous membranes, delayed capillary refill time, reduced borborygmi, and pronounced digital pulses. Diagnostic investigations included laboratory blood analysis, urinalysis, electrocardiogram, abdominal ultrasound, palpation per rectum and gastroscopy.

RESULTS

Patient assessment found evidence of toxicity to the gastrointestinal tract, hypovolaemia and risk for laminitis. Intensive care included fluid and electrolyte therapy, anti-inflammatories and analgesia, continuous digital cryotherapy, gastro-protectants and other methods of gastrointestinal support. The horse was discharged from hospital on day 14 with no long-term complications and the client-veterinarian relationship was preserved.

DISCUSSION

In human cases of ingestion, gastrointestinal injury is typically accompanied by severe metabolic acidosis and multiple organ dysfunction syndrome due to toxicity of other body systems that can contribute to non-survival. Formaldehyde toxicity in the present case predominantly affected the gastrointestinal tract, most likely a direct result of the route of administration. Aside from gastrointestinal injury, primary toxicity of other body systems was not confirmed. To prevent this medical error recurring, the referring veterinary clinic revised their labelling and storage of 10% formalin.

CONCLUSION

This is the first report of systemic formalin intoxication in the horse. Following a high dose of 10% formalin (0.12 g/kg bwt formaldehyde) enterally, the horse survived having received intensive supportive care based on human guidelines for ingested formalin.

Should Airway Hyper-Responsiveness Be Included in the Definition of Clinical Remission With Biologic Therapy in Severe Asthma

Airway hyper-responsiveness (AHR) is a tenet of the persistent asthma phenotype along with reversible airway obstruction and type 2 (T2) inflammation. Indirect acting challenges such as mannitol are more closely related to the underlying T2 inflammatory process as compared with direct challenges. In this review article, we summarise the current literature and explore the future role of mannitol AHR in clinical remission with biologics.

Intermittent hypoxic pretreatment exacerbates house dust mite-induced asthma airway inflammation

BACKGROUND

Asthma is widely recognized as an inflammatory disorder. In the context of this inflammatory microenvironment, the involvement of hypoxia and its impact on related pathways have drawn considerable attention. However, the exact role of hypoxia, a prevalent environmental factor, in the development and progression of asthma remains poorly understood.

METHODS

Mice were treated with house dust mite (HDM) extracts for 23 days to induce asthma. Mice were divided into room air (RA) group and intermittent hypoxic (IH) group by exposing to different conditions and IH preconditioning (IHP) were underwent to the above groups before the hypoxic regimen. Airway inflammation in mice was evaluated by airway hyperresponsiveness, excessive mucus secretion, and recruitment of inflammatory cells. Immunohistochemistry was employed to quantify the expression levels of NF-κB. Subsequently, the dose of allergen was modified to investigate whether the impact of hypoxia on asthma is affected by different doses of allergens.

RESULT

Compared to the RA and IH groups, HDM-treated mice in the IHP group exhibited aggravated inflammatory cell infiltration and airway hyperresponsiveness (p＜.05). Moreover, there was an increased release of inflammatory mediators and higher expression levels of NF-κB (p＜.05). Importantly, the impact ia on asthma was found to be influenced by high dose of allergen (p＜.05).

CONCLUSION

IHP treatment potentially exacerbates HDM-induced airway inflammation in asthma, with the involvement of NF-κB, particularly under high-dose allergen stimulation.

An umbrella review of the evidence associating occupational carcinogens and cancer risk at 19 anatomical sites

Occupational exposure to carcinogens of increasing cancer risk have been extensively suggested. A robust assessment of these evidence is needed to guide public policy and health care. We aimed to classify the strength of evidence for associations of 13 occupational carcinogens (OCs) and risk of cancers. We searched PubMed and Web of Science up to November 2022 to identify potentially relevant studies. We graded the evidence into convincing, highly suggestive, suggestive, weak, or not significant according to a standardized classification based on: random-effects p value, number of cancer cases, 95% confidence interval of largest study, heterogeneity between studies, 95% prediction interval, small study effect, excess significance bias and sensitivity analyses with credibility ceilings. The quality of meta-analysis was evaluated by AMSTAR 2. Forty-eight articles yielded 79 meta-analyses were included in current umbrella review. Evidence of associations were convincing (class I) or highly suggeastive (class II) for asbestos exposure and increasing risk of lung cancer among smokers (RR = 8.79, 95%CI: 5.81-13.25 for cohort studies and OR = 8.68, 95%CI: 5.68-13.24 for case-control studies), asbestos exposure and increasing risk of mesothelioma (RR = 4.61, 95%CI: 2.57-8.26), and formaldehyde exposure and increasing risk of sinonasal cancer (RR = 1.68, 95%CI: 1.38-2.05). Fifteen associations were supported by suggestive evidence (class III). In summary, the current umbrella review found strong associations between: asbestos exposure and increasing risk of lung cancer among smokers; asbestos exposure and increasing risk of mesothelioma; and formaldehyde exposure and higher risk of sinonasal cancer. Other associations might be genuine, but substantial uncertainty remains.

Formaldehyde Exposure Racial Disparities in Southeast Texas

Formaldehyde (HCHO) exposures during a full year were calculated for different race/ethnicity groups living in Southeast Texas using a chemical transport model tagged to track nine emission categories. Petroleum and industrial emissions were the largest anthropogenic sources of HCHO exposure in Southeast Texas, accounting for 44% of the total HCHO population exposure. Approximately 50% of the HCHO exposures associated with petroleum and industrial sources were directly emitted (primary), while the other 50% formed in the atmosphere (secondary) from precursor emissions of reactive compounds such as ethylene and propylene. Biogenic emissions also formed secondary HCHO that accounted for 11% of the total population-weighted exposure across the study domain. Off-road equipment contributed 3.7% to total population-weighted exposure in Houston, while natural gas combustion contributed 5% in Beaumont. Mobile sources accounted for 3.7% of the total HCHO population exposure, with less than 10% secondary contribution. Exposure disparity patterns changed with the location. Hispanic and Latino residents were exposed to HCHO concentrations +1.75% above average in Houston due to petroleum and industrial sources and natural gas sources. Black and African American residents in Beaumont were exposed to HCHO concentrations +7% above average due to petroleum and industrial sources, off-road equipment, and food cooking. Asian residents in Beaumont were exposed to HCHO concentrations that were +2.5% above average due to HCHO associated with petroleum and industrial sources, off-road vehicles, and food cooking. White residents were exposed to below average HCHO concentrations in all domains because their homes were located further from primary HCHO emission sources. Given the unique features of the exposure disparities in each region, tailored solutions should be developed by local stakeholders. Potential options to consider in the development of those solutions include modifying processes to reduce emissions, installing control equipment to capture emissions, or increasing the distance between industrial sources and residential neighborhoods.

A quantitative analysis of surgical smoke-derived particulate matter and formaldehyde exposure during spine surgery: a possible occupational hazard

OBJECTIVE

Since its introduction, electrocautery has served as a valuable surgical tool, enabling precise tissue cutting and effective hemostasis in spine surgery. While there have been numerous efforts to elucidate the possible hazardous effects of surgical smoke in various surgical fields, there has been very little discussion in the context of spine surgery. The objective of this study was to measure and conduct a quantitative analysis of the particulate matter (PM) of different sizes and of formaldehyde (HCHO) generated by smoke during spine surgeries.

METHODS

This study included a consecutive series of patients who underwent 1- or 2-level lumbar spinal fusion surgery between June and November 2021. Particle counts were measured using a particle counter, specifically focusing on six different sizes of PM (0.3, 0.5, 1, 2.5, 5, and 10 µm). Additionally, measurements were taken for HCHO in parts per million (ppm). Monopolar cautery was used in the surgical setting. Systematic measurements were conducted at specific time points during the surgical procedures to assess the levels of PM and HCHO. Furthermore, the efficacy of surgical smoke suction was evaluated by comparing the PM levels with and without adjacent placement of suction.

RESULTS

This study involved 35 patients, with measurements of both PM and HCHO taken in 27 cases. The remaining 8 cases had measurements only for PM. In this study, statistically significant quantitative changes in various PM sizes were observed when electrocautery was used during spine surgery (12.3 ± 1.7 vs 1975.7 ± 422.8, 3.4 ± 0.5 vs 250.1 ± 45.7, and 1.9 ± 0.2 vs 78.1 ± 13.3, respectively, for 2.5-, 5-, and 10-µm PM; p < 0.05). The level of HCHO was also significantly higher (0.085 ± 0.006 vs 0.131 ± 0.014 ppm, p < 0.05) with electrocautery use. Utilization of adjacent suction of surgical smoke during electrocautery demonstrated a statistically significant reduction in PM levels.

CONCLUSIONS

The findings of this study highlight the potential surgical smoke-related hazards that spine surgeons may be exposed to in the operating room. Implementing simple interventions, such as utilizing nearby suction, can effectively minimize the amount of toxic surgical smoke and mitigate these risks.

Risk prediction model construction for asthma after allergic rhinitis by blood immune T effector cells

BACKGROUND

Allergic rhinitis (AR) and asthma (AS) are prevalent and frequently co-occurring respiratory diseases, with mutual influence on each other. They share similar etiology, pathogenesis, and pathological changes. Due to the anatomical continuity between the upper and lower respiratory tracts, allergic inflammation in the nasal cavity can readily propagate downwards, leading to bronchial inflammation and asthma. AR serves as a significant risk factor for AS by potentially inducing airway hyperresponsiveness in patients. Currently, there is a lack of reliable predictors for the progression from AR to AS.

METHODS

In this exhaustive investigation, we reexamined peripheral blood single cell RNA sequencing datasets from patients with AS following AR and healthy individuals. In addition, we used the bulk RNA sequencing dataset as a validation lineup, which included AS, AR, and healthy controls. Using marker genes of related cell subtype, signatures predicting the progression of AR to AS were generated.

RESULTS

We identified a subtype of immune-activating effector T cells that can distinguish patients with AS after AR. By combining specific marker genes of effector T cell subtype, we established prediction models of 16 markers. The model holds great promise for assessing AS risk in individuals with AR, providing innovative avenues for clinical diagnosis and treatment strategies.

CONCLUSION

Subcluster T effector cells may play a key role in post-AR AS. Notably, ACTR3 and HSPA8 genes were significantly upregulated in the blood of AS patients compared to healthy patients.

Formaldehyde aggravates airway inflammation through induction of glycolysis in an experimental model of asthma exacerbated by lipopolysaccharide

Formaldehyde (FA) exposure has been reported to induce or aggravate allergic asthma. Infection is also a potential risk factor for the onset and aggravation of asthma. However, no study has addressed the effects of FA exposure on asthmatic patients with respiratory infection. FA is ubiquitous in environment and respiratory infections are common in clinics. Therefore, it is necessary to explore whether FA exposure leads to the further worsening of symptoms in asthma patients with existing respiratory infection. In the present study, ovalbumin (OVA) was used to establish the murine asthma model. Lipopolysaccharide (LPS) was intratracheal administrated to mimic asthma with respiratory infection. The mice were exposed to 0.5 mg/m3 FA. FA exposure did not induce a significant aggravation on OVA induced allergic asthma. However, the lung function of specific airway resistance (sRaw), histological changes and cytokines production were greatly aggravated by FA exposure in OVA/LPS induced murine asthma model. Monocyte-derived macrophages (MDMs) were isolated from asthmatic patients. Exposure of MDMs to FA and LPS resulted in increased TNF-α, IL-6, IL-1β, and nitric oxide (NO) production. Lactate produciton and lactate dehydrogenase A (LDHA) expression were found to be upregulated by FA in OVA/LPS induced asthmatic mice and LPS stimulated MDMs. Furthermore, glycolysis inhibitor 2-Deoxy-d-glucose attenuated FA and LPS induced TNF-α, IL-6, IL-1β, and NO production. We conclude that FA exposure can lead to the aggravation of allergic asthma with infection through induction of glycolysis. This study could offer some new insight into how FA promotes asthma development.

[Standard technical specifications for methacholine chloride (Methacholine) bronchial challenge test (2023)]

The methacholine challenge test (MCT) is a standard evaluation method of assessing airway hyperresponsiveness (AHR) and its severity, and has significant clinical value in the diagnosis and treatment of bronchial asthma. A consensus working group consisting of experts from the Pulmonary Function and Clinical Respiratory Physiology Committee of the Chinese Association of Chest Physicians, the Task Force for Pulmonary Function of the Chinese Thoracic Society, and the Pulmonary Function Group of Respiratory Branch of the Chinese Geriatric Society jointly developed this consensus. Based on the "Guidelines for Pulmonary Function-Bronchial Provocation Test" published in 2014, the issues encountered in its use, and recent developments, the group has updated the Standard technical specifications of methacholine chloride (methacholine) bronchial challenge test (2023). Through an extensive collection of expert opinions, literature reviews, questionnaire surveys, and multiple rounds of online and offline discussions, the consensus addressed the eleven core issues in MCT's clinical practice, including indications, contraindications, preparation of provocative agents, test procedures and methods, quality control, safety management, interpretation of results, and reporting standards. The aim was to provide clinical pulmonary function practitioners in healthcare institutions with the tools to optimize the use of this technique to guide clinical diagnosis and treatment.Summary of recommendationsQuestion 1: Who is suitable for conducting MCT? What are contraindications for performing MCT?Patients with atypical symptoms and a clinical suspicion of asthma, patients diagnosed with asthma requiring assessment of the severity of airway hyperresponsiveness, individuals with allergic rhinitis who are at risk of developing asthma, patients in need of evaluating the effectiveness of asthma treatment, individuals in occupations with high safety risks due to airway hyperresponsiveness, patients with chronic diseases prone to airway hyperresponsiveness, others requiring assessment of airway reactivity.Absolute contraindications: (1) Patients who are allergic to methacholine (MCh) or other parasympathomimetic drugs, with allergic reactions including rash, itching/swelling (especially of the face, tongue, and throat), severe dizziness, and dyspnea; (2) Patients with a history of life-threatening asthma attacks or those who have required mechanical ventilation for asthma attacks in the past three months; (3) Patients with moderate to severe impairment of baseline pulmonary function [Forced Expiratory Volume in one second (FEV1) less than 60% of the predicted value or FEV1<1.0 L]; (4) Severe urticaria; (5) Other situations inappropriate for forced vital capacity (FVC) measurement, such as myocardial infarction or stroke in the past three months, poorly controlled hypertension, aortic aneurysm, recent eye surgery, or increased intracranial pressure.Relative contraindications: (1) Moderate or more severe impairment of baseline lung function (FEV1%pred<70%), but individuals with FEV1%pred>60% may still be considered for MCT with strict observation and adequate preparation; (2) Experiencing asthma acute exacerbation; (3) Poor cooperation with baseline lung function tests that do not meet quality control requirements; (4) Recent respiratory tract infection (<4 weeks); (5) Pregnant or lactating women; (6) Patients currently using cholinesterase inhibitors (for the treatment of myasthenia gravis); (7) Patients who have previously experienced airway spasm during pulmonary function tests, with a significant decrease in FEV1 even without the inhalation of provocative.Question 2: How to prepare and store the challenge solution for MCT?Before use, the drug must be reconstituted and then diluted into various concentrations for provocation. The dilution concentration and steps for MCh vary depending on the inhalation method and provocation protocol used. It is important to follow specific steps. Typically, a specified amount of diluent is added to the methacholine reagent bottle for reconstitution, and the mixture is shaken until the solution becomes clear. The diluent is usually physiological saline, but saline with phenol (0.4%) can also be used. Phenol can reduce the possibility of bacterial contamination, and its presence does not interfere with the provocation test. After reconstitution, other concentrations of MCh solution are prepared using the same diluent, following the dilution steps, and then stored separately in sterile containers. Preparers should carefully verify and label the concentration and preparation time of the solution and complete a preparation record form. The reconstituted and diluted MCh solution is ready for immediate use without the need for freezing. It can be stored for two weeks if refrigerated (2-8 ℃). The reconstituted solution should not be stored directly in the nebulizer reservoir to prevent crystallization from blocking the capillary opening and affecting aerosol output. The temperature of the solution can affect the production of the nebulizer and cause airway spasms in the subject upon inhaling cold droplets. Thus, refrigerated solutions should be brought to room temperature before use.Question 3: What preparation is required for subjects prior to MCT?(1) Detailed medical history inquiry and exclusion of contraindications.(2) Inquiring about factors and medications that may affect airway reactivity and assessing compliance with medication washout requirements: When the goal is to evaluate the effectiveness of asthma treatment, bronchodilators other than those used for asthma treatment do not need to be discontinued. Antihistamines and cromolyn have no effect on MCT responses, and the effects of a single dose of inhaled corticosteroids and leukotriene modifiers are minimal, thus not requiring cessation before the test. For patients routinely using corticosteroids, whether to discontinue the medication depends on the objective of the test: if assisting in the diagnosis of asthma, differential diagnosis, aiding in step-down therapy for asthma, or exploring the effect of discontinuing anti-inflammatory treatment, corticosteroids should be stopped before the provocation test; if the patient is already diagnosed with asthma and the objective is to observe the level of airway reactivity under controlled medication conditions, then discontinuation is not necessary. Medications such as IgE monoclonal antibodies, IL-4Rα monoclonal antibodies, traditional Chinese medicine, and ethnic medicines may interfere with test results, and clinicians should decide whether to discontinue these based on the specific circumstances.(3) Explaining the test procedure and potential adverse reactions, and obtaining informed consent if necessary.Question 4: What are the methods of the MCT? And which ones are recommended in current clinical practice?Commonly used methods for MCT in clinical practice include the quantitative nebulization method (APS method), Forced Oscillalion method (Astograph method), 2-minute tidal breathing method (Cockcroft method), hand-held quantitative nebulization method (Yan method), and 5-breath method (Chai 5-breath method). The APS method allows for precise dosing of inhaled Methacholine, ensuring accurate and reliable results. The Astograph method, which uses respiratory resistance as an assessment indicator, is easy for subjects to perform and is the simplest operation. These two methods are currently the most commonly used clinical practice in China.Question 5: What are the steps involved in MCT?The MCT consists of the following four steps:(1) Baseline lung function test: After a 15-minute rest period, the subjects assumes a seated position and wear a nose clip for the measurement of pulmonary function indicators [such as FEV1 or respiratory resistance (Rrs)]. FEV1 should be measured at least three times according to spirometer quality control standards, ensuring that the best two measurements differ by less than 150 ml and recording the highest value as the baseline. Usually, if FEV1%pred is below 70%, proceeding with the challenge test is not suitable, and a bronchodilation test should be considered. However, if clinical assessment of airway reactivity is necessary and FEV1%pred is between 60% and 70%, the provocation test may still be conducted under close observation, ensuring the subject's safety. If FEV1%pred is below 60%, it is an absolute contraindication for MCT.(2) Inhalation of diluent and repeat lung function test for control values: the diluent, serving as a control for the inhaled MCh, usually does not significantly impact the subject's lung function. the higher one between baseline value and the post-dilution FEV1 is used as the reference for calculating the rate of FEV1 decline. If post-inhalation FEV1 decreases, there are usually three scenarios: ①If FEV1 decreases by less than 10% compared to the baseline, the test can proceed, continue the test and administer the first dose of MCh. ②If the FEV1 decreases by≥10% and<20%, indicating a heightened airway reactivity to the diluent, proceed with the lowest concentration (dose) of the provoking if FEV1%pred has not yet reached the contraindication criteria for the MCT. if FEV1%pred<60% and the risk of continuing the challenge test is considerable, it is advisable to switch to a bronchodilation test and indicate the change in the test results report. ③If FEV1 decreases by≥20%, it can be directly classified as a positive challenge test, and the test should be discontinued, with bronchodilators administered to alleviate airway obstruction.(3) Inhalation of MCh and repeat lung function test to assess decline: prepare a series of MCh concentrations, starting from the lowest and gradually increasing the inhaled concentration (dose) using different methods. Perform pulmonary function tests at 30 seconds and 90 seconds after completing nebulization, with the number of measurements limited to 3-4 times. A complete Forced Vital Capacity (FVC) measurement is unnecessary during testing; only an acceptable FEV1 measurement is required. The interval between two consecutive concentrations (doses) generally should not exceed 3 minutes. If FEV1 declines by≥10% compared to the control value, reduce the increment of methacholine concentration (dose) and adjust the inhalation protocol accordingly. If FEV1 declines by≥20% or more compared to the control value or if the maximum concentration (amount) has been inhaled, the test should be stopped. After inhaling the MCh, close observation of the subject's response is necessary. If necessary, monitor blood oxygen saturation and auscultate lung breath sounds. The test should be promptly discontinued in case of noticeable clinical symptoms or signs.(4) Inhalation of bronchodilator and repeat lung function test to assess recovery: when the bronchial challenge test shows a positive response (FEV1 decline≥20%) or suspiciously positive, the subject should receive inhaled rapid-acting bronchodilators, such as short-acting beta-agonists (SABA) or short-acting muscarinic antagonists (SAMA). Suppose the subject exhibits obvious symptoms of breathlessness, wheezing, or typical asthma manifestations, and wheezing is audible in the lungs, even if the positive criteria are not met. In that case, the challenge test should be immediately stopped, and rapid-acting bronchodilators should be administered. Taking salbutamol as an example, inhale 200-400 μg (100 μg per puff, 2-4 puffs, as determined by the physician based on the subject's condition). Reassess pulmonary function after 5-10 minutes. If FEV1 recovers to within 10% of the baseline value, the test can be concluded. However, if there is no noticeable improvement (FEV1 decline still≥10%), record the symptoms and signs and repeat the bronchodilation procedure as mentioned earlier. Alternatively, add Ipratropium bromide (SAMA) or further administer nebulized bronchodilators and corticosteroids for intensified treatment while keeping the subject under observation until FEV1 recovers to within 90% of the baseline value before allowing the subject to leave.Question 6: What are the quality control requirements for the APS and Astograph MCT equipment?(1) APS Method Equipment Quality Control: The APS method for MCT uses a nebulizing inhalation device that requires standardized flowmeters, compressed air power source pressure and flow, and nebulizer aerosol output. Specific quality control methods are as follows:a. Flow and volume calibration of the quantitative nebulization device: Connect the flowmeter, an empty nebulization chamber, and a nebulization filter in sequence, attaching the compressed air source to the bottom of the chamber to ensure airtight connections. Then, attach a 3 L calibration syringe to the subject's breathing interface and simulate the flow during nebulization (typically low flow:<2 L/s) to calibrate the flow and volume. If calibration results exceed the acceptable range of the device's technical standards, investigate and address potential issues such as air leaks or increased resistance due to a damp filter, then recalibrate. Cleaning the flowmeter or replacing the filter can change the resistance in the breathing circuit, requiring re-calibration of the flow.b. Testing the compressed air power source: Regularly test the device, connecting the components as mentioned above. Then, block the opening of the nebulization device with a stopper or hand, start the compressed air power source, and test its pressure and flow. If the test results do not meet the technical standards, professional maintenance of the equipment may be required.c. Verification of aerosol output of the nebulization chamber: Regularly verify all nebulization chambers used in provocation tests. Steps include adding a certain amount of saline to the chamber, weighing and recording the chamber's weight (including saline), connecting the nebulizer to the quantitative nebulization device, setting the nebulization time, starting nebulization, then weighing and recording the post-nebulization weight. Calculate the unit time aerosol output using the formula [(weight before nebulization-weight after nebulization)/nebulization time]. Finally, set the nebulization plan for the provocation test based on the aerosol output, considering the MCh concentration, single inhalation nebulization duration, number of nebulization, and cumulative dose to ensure precise dosing of the inhaled MCh.(2) Astograph method equipment quality control: Astograph method equipment for MCT consists of a respiratory resistance monitoring device and a nebulization medication device. Perform zero-point calibration, volume calibration, impedance verification, and nebulization chamber checks daily before tests to ensure the resistance measurement system and nebulization system function properly. Calibration is needed every time the equipment is turned on, and more frequently if there are significant changes in environmental conditions.a. Zero-point calibration: Perform zero-point calibration before testing each subject. Ensure the nebulization chamber is properly installed and plugged with no air leaks.b. Volume calibration: Use a 3 L calibration syringe to calibrate the flow sensor at a low flow rate (approximately 1 L/s).c. Resistance verification: Connect low impedance tubes (1.9-2.2 cmH2O·L-1·s-1) and high impedance tubes (10.2-10.7 cmH2O·L-1·s-1) to the device interface for verification.d. Bypass check: Start the bypass check and record the bypass value; a value>150 ml/s is normal.e. Nebulization chamber check: Check each of the 12 nebulization chambers daily, especially those containing bronchodilators, to ensure normal spraying. The software can control each nebulization chamber to produce spray automatically for a preset duration (e.g., 2 seconds). Observe the formation of water droplets on the chamber walls, indicating normal spraying. If no nebulization occurs, check for incorrect connections or blockages.Question 7: How to set up and select the APS method in MCT?The software program of the aerosol provocation system in the quantitative nebulization method can independently set the nebulizer output, concentration of the methacholine agent, administration time, and number of administrations and combine these parameters to create the challenge test process. In principle, the concentration of the methacholine agent should increase from low to high, and the dose should increase from small to large. According to the standard, a 2-fold or 4-fold incremental challenge process is generally used. In clinical practice, the dose can be simplified for subjects with good baseline lung function and no history of wheezing, such as using a recommended 2-concentration, 5-step method (25 and 50 g/L) and (6.25 and 25 g/L). Suppose FEV1 decreases by more than 10% compared to the baseline during the test to ensure subject safety. In that case, the incremental dose of the methacholine agent can be reduced, and the inhalation program can be adjusted appropriately. If the subject's baseline lung function declines or has recent daytime or nighttime symptoms such as wheezing or chest tightness, a low concentration, low dose incremental process should be selected.Question 8: What are the precautions for the operation process of the Astograph method in MCT?(1) Test equipment: The Astograph method utilizes the forced oscillation technique, applying a sinusoidal oscillating pressure at the mouthpiece during calm breathing. Subjects inhale nebulized MCh of increasing concentrations while continuous monitoring of respiratory resistance (Rrs) plots the changes, assessing airway reactivity and sensitivity. The nebulization system employs jet nebulization technology, comprising a compressed air pump and 12 nebulization cups. The first cup contains saline, cups 2 to 11 contain increasing concentrations of MCh, and the 12th cup contains a bronchodilator solution.(2) Provocation process: Prepare 10 solutions of MCh provocant with gradually increasing concentrations.(3) Operational procedure: The oscillation frequency is usually set to 3 Hz (7 Hz for children) during the test. The subject breathes calmly, inhales saline solution nebulized first, and records the baseline resistance value (if the subject's baseline resistance value is higher than 10 cmH2O·L-1·s-1, the challenge test should not be performed). Then, the subject gradually inhales increasing concentrations of methacholine solution. Each concentration solution is inhaled for 1 minute, and the nebulization system automatically switches to the next concentration for inhalation according to the set time. Each nebulizer cup contains 2-3 ml of solution, the output is 0.15 ml/min, and each concentration is inhaled for 1 minute. The dose-response curve is recorded automatically. Subjects should breathe tidally during the test, avoiding deep breaths and swallowing. Continue until Rrs significantly rises to more than double the baseline value, or if the subject experiences notable respiratory symptoms or other discomfort, such as wheezing in both lungs upon auscultation. At this point, the inhalation of the provocant should be stopped and the subject switchs to inhaling a bronchodilator until Rrs returns to pre-provocation levels. If there is no significant increase in Rrs, stop the test after inhaling the highest concentration of MCh.Question 9: How to interpret the results of the MCT?The method chosen for the MCT determines the specific indicators used for interpretation. The most commonly used indicator is FEV1, although other parameters such as Peak Expiratory Flow (PEF) and Rrs can also be used to assess airway hyperresponsiveness.Qualitative judgment: The test results can be classified as positive, suspiciously positive, or negative, based on a combination of the judgment indicators and changes in the subject's symptoms. If FEV1 decreases by≥20% compared to the baseline value after not completely inhaling at the highest concentration, the result can be judged as positive for Methacholine bronchial challenge test. If the patient has obvious wheezing symptoms or wheezing is heard in both lungs, but the challenge test does not meet the positive criteria (the highest dose/concentration has been inhaled), and FEV1 decreases between 10% and 20% compared to the baseline level, the result can also be judged as positive. If FEV1 decreases between 15% and 20% compared to the baseline value without dyspnea or wheezing attacks, the result can be judged as suspiciously positive. Astograph method: If Rrs rises to 2 times or more of the baseline resistance before reaching the highest inhalation concentration, or if the subject's lungs have wheezing and severe coughing, the challenge test can be judged as positive. Regardless of the result of the Methacholine bronchial challenge test, factors that affect airway reactivity, such as drugs, seasons, climate, diurnal variations, and respiratory tract infections, should be excluded.Quantitative judgment: When using the APS method, the severity of airway hyperresponsiveness can be graded based on PD20-FEV1 or PC20-FEV1. Existing evidence suggests that PD20 shows good consistency when different nebulizers, inhalation times, and starting concentrations of MCh are used for bronchial provocation tests, whereas there is more variability with PC20. Therefore, PD20 is often recommended as the quantitative assessment indicator. The threshold value for PD20 with the APS method is 2.5 mg.The Astograph method often uses the minimum cumulative dose (Dmin value, in Units) to reflect airway sensitivity. Dmin is the minimum cumulative dose of MCh required to produce a linear increase in Rrs. A dose of 1 g/L of the drug concentration inhaled for 1-minute equals 1 unit. It's important to note that with the continuous increase in inhaled provocant concentration, the concept of cumulative dose in the Astograph method should not be directly compared to other methods. Most asthma patients have a Dmin<10 Units, according to Japanese guidelines. The Astograph method, having been used in China for over twenty years, suggests a high likelihood of asthma when Dmin≤6 Units, with a smaller Dmin value indicating a higher probability. When Dmin is between 6 and 10 Units, further differential diagnosis is advised to ascertain whether the condition is asthma.Precautions:A negative methacholine challenge test (MCT) does not entirely rule out asthma. The test may yield negative results due to the following reasons:(1) Prior use of medications that reduce airway responsiveness, such as β2 agonists, anticholinergic drugs, antihistamines, leukotriene receptor antagonists, theophylline, corticosteroids, etc., and insufficient washout time.(2) Failure to meet quality control standards in terms of pressure, flow rate, particle size, and nebulization volume of the aerosol delivery device.(3) Poor subject cooperation leads to inadequate inhalation of the methacholine agent.(4) Some exercise-induced asthma patients may not be sensitive to direct bronchial challenge tests like the Methacholine challenge and require indirect bronchial challenge tests such as hyperventilation, cold air, or exercise challenge to induce a positive response.(5) A few cases of occupational asthma may only react to specific antigens or sensitizing agents, requiring specific allergen exposure to elicit a positive response.A positive MCT does not necessarily indicate asthma. Other conditions can also present with airway hyperresponsiveness and yield positive results in the challenge test, such as allergic rhinitis, chronic bronchitis, viral upper respiratory infections, allergic alveolitis, tropical eosinophilia, cystic fibrosis, sarcoidosis, bronchiectasis, acute respiratory distress syndrome, post-cardiopulmonary transplant, congestive heart failure, and more. Furthermore, factors like smoking, air pollution, or exercise before the test may also result in a positive bronchial challenge test.Question 10: What are the standardized requirements for the MCT report?The report should include: (1) basic information about the subject; (2) examination data and graphics: present baseline data, measurement data after the last two challenge doses or concentrations in tabular form, and the percentage of actual measured values compared to the baseline; flow-volume curve and volume-time curve before and after challenge test; dose-response curve: showing the threshold for positive challenge; (3) opinions and conclusions of the report: including the operator's opinions, quality rating of the examination, and review opinions of the reviewing physician.Question 11: What are the adverse reactions and safety measures of MCT?During the MCT, the subject needs to repeatedly breathe forcefully and inhale bronchial challenge agents, which may induce or exacerbate bronchospasm and contraction and may even cause life-threatening situations. Medical staff should be fully aware of the indications, contraindications, medication use procedures, and emergency response plans for the MCT.

Is bronchial provocation test positivity associated with blood eosinophil count and cut-off value?

OBJECTIVE

Asthma is characterized by airway hyperresponsiveness due to chronic inflammation in the airways. One of the main cells involved in airway inflammation is eosinophils. In the current study, a bronchial provocation test (BPT) was performed to demonstrate airway hyperresponsiveness. We investigated the relationship between BPT and blood eosinophil count and the cut-off value of blood eosinophil count.

PATIENTS AND METHODS

In this study, we retrospectively evaluated the data of 246 patients who visited our immunology and allergy clinic, a tertiary reference center, with asthma symptoms between May 2017 and March 2020 and underwent BPT with methacholine for the diagnosis of asthma. The cases were grouped according to the level of BPT positivity and negativity.

RESULTS

Of 246 patients, BPT was positive in 90 (36.6%) and negative in 156 (63.4%). The blood eosinophil measurement of the BPT-positive cases was found to be statistically significantly higher than that of the BPT-negative cases (135 vs. 119 cells/µl, respectively, p=0.029). When BPT is grouped according to positivity levels, there was no statistically significant difference in blood eosinophil measurements between subgroups (p=0.174). As a result of the evaluations, the cut-off point obtained for the blood eosinophil count was determined as ≥226 cells/µl. For the blood eosinophil count, for the cut-off value of ≥226 cells/µl, sensitivity was 30.0%, specificity 87.7%, positive predictive value 58.7%, and negative predictive value 68.3%.

CONCLUSIONS

This study shows that BPT positivity is associated with blood eosinophil count. The cut-off value (≥226 cells/µl) determined for blood eosinophil count may be helpful when planning BPT and evaluating the diagnosis of asthma.

Group III secreted phospholipase A2 -driven lysophospholipid pathway protects against allergic asthma

Asthma is a chronic inflammatory disease of the airways characterized by recurrent episodes of airway obstruction, hyperresponsiveness, remodeling, and eosinophilia. Phospholipase A2 s (PLA2 s), which release fatty acids and lysophospholipids from membrane phospholipids, have been implicated in exacerbating asthma by generating pro-asthmatic lipid mediators, but an understanding of the association between individual PLA2 subtypes and asthma is still incomplete. Here, we show that group III-secreted PLA2 (sPLA2 -III) plays an ameliorating, rather than aggravating, role in asthma pathology. In both mouse and human lungs, sPLA2 -III was expressed in bronchial epithelial cells and decreased during the asthmatic response. In an ovalbumin (OVA)-induced asthma model, Pla2g3-/- mice exhibited enhanced airway hyperresponsiveness, eosinophilia, OVA-specific IgE production, and type 2 cytokine expression as compared to Pla2g3+/+ mice. Lipidomics analysis showed that the pulmonary levels of several lysophospholipids, including lysophosphatidylcholine, lysophosphatidylethanolamine, and lysophosphatidic acid (LPA), were decreased in OVA-challenged Pla2g3-/- mice relative to Pla2g3+/+ mice. LPA receptor 2 (LPA2 ) agonists suppressed thymic stromal lymphopoietin (TSLP) expression in bronchial epithelial cells and reversed airway hyperresponsiveness and eosinophilia in Pla2g3-/- mice, suggesting that sPLA2 -III negatively regulates allergen-induced asthma at least by producing LPA. Thus, the activation of the sPLA2 -III-LPA pathway may be a new therapeutic target for allergic asthma.

Steroid-Insensitive Gene Expression of Extracellular Matrix Components and Pro-fibrotic Factors in the Lung Associated with Airway Hyperresponsiveness in Murine Asthma

Between 5 and 10% of asthma patients do not respond to glucocorticoid therapy. Experimental animal models are indispensable for investigating the pathogenesis of steroid-resistant asthma; however, the majority of murine asthma models respond well to glucocorticoids. We previously reported that multiple intratracheal administration of ovalbumin (OVA) at a high dose (500 µg/animal) induced steroid-insensitive airway eosinophilia and remodeling with lung fibrosis, whereas a low dose (5 µg/animal) caused steroid-sensitive responses. The aims of the present study were as follows: 1) to clarify whether airway hyperresponsiveness (AHR) in the two models is also insensitive and sensitive to a glucocorticoid, respectively, and 2) to identify steroid-insensitive genes encoding extracellular matrix (ECM) components and pro-fibrotic factors in the lung. In comparisons with non-challenged group, the 5- and 500-µg OVA groups both exhibited AHR to methacholine. Daily intraperitoneal treatment with dexamethasone (1 mg/kg) significantly suppressed the development of AHR in the 5-µg OVA group, but not in the 500-µg OVA group. Among genes encoding ECM components and pro-fibrotic factors, increased gene expressions of fibronectin and collagen types I, III, and IV as ECM components as well as 7 matrix metalloproteinases, tissue inhibitor of metalloproteinase-1, transforming growth factor-β1, and activin A/B as pro-fibrotic factors were insensitive to dexamethasone in the 500-µg OVA group, but were sensitive in the 5-µg OVA group. In conclusion, steroid-insensitive AHR developed in the 500-µg OVA group and steroid-insensitive genes encoding ECM components and pro-fibrotic factors were identified. Drugs targeting these molecules have potential in the treatment of steroid-resistant asthma.

Impact of obesity in asthma: Possible future therapies

Obesity is one of the factors associated with the severity of asthma. Obesity is associated with aggravation of the pathophysiology of asthma, including exacerbations, airway inflammation, decreased pulmonary function, and airway hyperresponsiveness. The present review addresses the characteristics of asthma with obesity, focusing especially on the heterogeneity caused by the degree of type 2 inflammation, sex differences, the onset of asthma, and race differences. To understand the severity mechanisms in asthma and obesity, such as corticosteroid resistance, fatty acids, gut microbiome, and cytokines, several basic research studies are evaluated. Finally, possible future therapies, including weight reduction, microbiome-targeted therapies, and other molecular targeted therapies are addressed. We believe that the present review will contribute to better understanding of the severity mechanisms and the establishment of novel treatments for severe asthma patients with obesity.

Influence of formaldehyde exposure on the molecules of the NO/cGMP-cAMP signaling pathway in different brain regions of Balb/c mice

This toxicology study was conducted to assess the impact of formaldehyde, a common air pollutant found in Chinese gymnasiums, on the brain function of athletes. In this research, a total of 24 Balb/c male mice of SPF-grade were divided into four groups, each consisting of six mice. The mice were exposed to formaldehyde at different concentrations, including 0 mg/m3, 0.5 mg/m3, 3.0 mg/m3, and 3.0 mg/m3 in combination with an injection of L-NMMA (NG-monomethyl-L-arginine), which is a nitric oxide synthase antagonist. Following a one-week test period (8 h per day, over 7 days), measurements of biomarkers related to the nitric oxide (NO)/cGMP-cAMP signaling pathway were carried out on the experimental animals post-treatment. The study found that: (1) Exposure to formaldehyde can lead to brain cell apoptosis and neurotoxicity; (2) Additionally, formaldehyde exposure was found to alter the biomarkers of the NO/cGMP-cAMP signaling pathway, with some changes being statistically significant (p < 0.05 or p < 0.01); (3) The use of L-NMMA, an antagonist of the NO/cGMP-cAMP signaling pathway, was found to prevent these biomarker changes and had a protective effect on brain cells. The study suggests that the negative impact of formaldehyde on the brain function of mice is linked to the regulation of the NO/cGMP-cAMP signaling pathway.

The Expression of Semaphorin3E in Vagal Ganglion and Lung Tissue Is Related to Airway Hyperresponsiveness in Murine Asthma Model

Objective

Semaphorin3E (Sema3E) mediates reorganization of the actin cytoskeleton, and plays an important role in ensuring the specificity of synapse formation and angiogenesis. However, the role of Sema3E in allergic asthma (AS) and eosinophilic bronchitis (EB) is still elusive. This study aimed to investigate the relationship between Sema3E in vagal ganglion and lung tissue, airway reactivity, and eosinophilic inflammation.

Methods

The frequency of coughs and airway reactivity as well as the airway inflammation were observed in ovalbumin- (OVA-) induced AS and EB mouse models. The expression of Sema3E was examined in the vagal ganglion and lung tissues by immunofluorescence staining and western blotting analyses. In the Sema3E treatment protocol, exogenous Sema3E was administrated intranasally before challenge in AS model to study the effect of Sema3E on airway hyperresponsiveness, airway inflammation, mucus production, and collagen deposition.

Results

The similar higher frequency of coughs and airway eosinophilic inflammation could be seen in AS and EB groups compared with nasal saline (NS) and dexamethasone (DXM) groups. The absence of the airway hyperresponsiveness was observed in EB and DXM group, while AS group showed increase in airway reactivity to methacholine. The expression of Sema3E in vagal ganglion and lung tissue was remarkably decreased in AS and DXM group compared with EB group. Sema3E-treated asthma mice displayed ameliorated airway hyperresponsiveness, mucus production, and collagen deposition.

Conclusion

Sema3E in lungs and vagal ganglia is related to eosinophilic inflammation and has a protective effect on OVA-induced AHR in asthma.

Stigmasterol alleviates allergic airway inflammation and airway hyperresponsiveness in asthma mice through inhibiting substance-P receptor

CONTEXT

Stigmasterol has significant anti-arthritis and anti-inflammatory effects, but its role in immune and inflammatory diseases is still unclear.

OBJECTIVE

The potential advantages of stigmasterol in asthma were explored in IL-13-induced BEAS-2B cells and asthmatic mice.

MATERIALS AND METHODS

The optimal target of stigmasterol was confirmed in asthma. After detecting the cytotoxicity of stigmasterol in BEAS-2B cells, 10 μg/mL and 20 μg/mL stigmasterol were incubated with the BEAS-2B cell model for 48 h, and anti-inflammation and antioxidative stress were verified. Asthmatic mice were induced by OVA and received 100 mg/kg stigmasterol for 7 consecutive days. After 28 days, lung tissues and BAL fluid were collected for the following study. To further verify the role of NK1-R, 0.1 μM WIN62577 (NK1-R specific antagonist), and 1 μM recombinant human NK1-R protein were applied.

RESULTS

NK1-R was the potential target of stigmasterol. When the concentration of stigmasterol is 20 μg/mL, the survival rate of BEAS-2B cells is about 98.4%, which is non-toxic. Stigmasterol exerted anti-inflammation and antioxidant stress in a dose-dependent manner and decreased NK1-R expression in IL-13-induced BEAS-2B. Meanwhile, in vivo assay also indicated the anti-inflammation and antioxidant stress of stigmasterol after OVA challenge. Stigmasterol inhibited inflammation infiltration and mucus hypersecretion, and NK1-R expression.

DISCUSSION AND CONCLUSIONS

The protective effect of stigmaterol on asthma and its underlying mechanism have been discussed in depth, providing a theoretical basis and more possibilities for its treatment of asthma.

Allergy to fungi: Advances in the understanding of fungal allergens

Allergic diseases are a major health problem due to their increasing incidence and high prevalence worldwide. Asthma has several aetiologies, and allergy plays an important role in its development in approximately 60% of adults and 80% of children and adolescents. Although the link between aeroallergen sensitization and asthma exacerbations has been long recognized, the investigations of the triggering allergens may be superficial in many asthma cases. The main allergenic sources related to asthma, and other allergic diseases, are pollens, mites, fungi, and animal epithelia. Fungi are considered the third most frequent cause of respiratory pathologies. Asthma caused by several fungi species may have a bad prognosis in some cases due to its severity and difficulty in avoidance methods. Despite the recognised relevance of fungi in respiratory allergies, the knowledge about fungal allergens seems to be scarce, with few descriptions of new allergens, compared to other allergenic sources. The study of major, minor, and cross-reactive fungal allergens, and their relevance in the allergic disease, might be crucial, not only to accurately diagnose these allergies, but also to predict exacerbations and responses to therapies, as well as for the development of personalized treatment plans in a fast-changing climate scenario.

Mediation of endoplasmic reticulum stress and NF-κB signaling pathway in DINP-exacerbated allergic asthma: A toxicological study with Balb/c mice

Epidemiological evidence indicates a significant relationship between exposure to diisononyl phthalate and allergic asthma. Despite this, the mechanism underlying this association remains unclear. Previous toxicological researches have suggested that the development of allergic asthma may involve the activation of endoplasmic reticulum stress (ERS) and the nuclear factor κ-B (NF-κB) pathways. Nevertheless, it is currently unknown whether these specific signaling pathways are implicated in diisononyl phthalate (DINP)-induced allergic asthma. The objective of this research was to understand how DINP exacerbates allergic asthma in Balb/c mice through ERS and NF-κB pathways. To systematically examine the aggravated effects of DINP in Balb/c mice, we measured airway hyperresponsiveness (AHR), lung tissue pathology, cytokines, and ERS and NF-κB pathway biomarkers. Additionally, we applied the ERS antagonist phenylbutyric acid (4-PBA) or the NF-κB antagonist pyrrolidine dithiocarbamate (PDTC) to verify the mediating effects of ERS and NF-κB on DINP-exacerbated allergic asthma. The results of our experiment show that oral DINP exposure may exacerbate airway hyperresponsiveness and airway remodeling. This deterioration is accompanied by an imbalance in immunoglobulin levels, Th17/Treg cells, ERS, and NF-κB biomarkers, leading to the activation of pro-inflammatory pathways. Furthermore, our study found that the blocking effect of 4-PBA or PDTC can inhibit the Th17/Treg imbalance and effectively alleviate symptoms resembling allergic asthma. In conclusion, ERS and NF-κB signaling pathways play an important role in regulating DINP-induced allergic asthma exacerbations.

Broncho-Vaxom bacterial lysate prevents asthma via acetate enhancement in mouse model

PURPOSE

Broncho-Vaxom (BV) is known to attenuate allergic airway inflammation and chronic bronchitis in humans, but the underlying mechanism of this gut-mediated immunity remains unclear. This study investigated the effects of an oral BV on gut and systemic short-chain fatty acids (SCFAs) and immune responses.

METHODS

Oral BV was administered daily for 15 days prior to commencing the study in an asthma mouse model. Asthma was induced by ovalbumin (OVA) sensitization followed by a challenge with 1% OVA by inhalation. Asthmatic phenotypes, gut- and systemic- immune responses, and SCFAs in the cecum and blood were then investigated.

RESULTS

Airway hyperresponsiveness, total immunoglobulin E production, and pulmonary inflammation were all significantly suppressed by BV. The interleukin-13 level was also suppressed, whereas TGF-β expression was increased, in the lungs of the BV-treated mice. The regulatory T (Treg) cell numbers were increased in the small intestine, and the acetate level was increased in the cecum and serum after BV treatment. The levels of acetate in the cecum and serum were negatively correlated with airway hyperresponsiveness and with the eosinophil numbers in the BAL fluid of the OVA-induced mice. There was a positive correlation between the acetate levels in the feces and serum and the lung expression of TGF-β in the asthma mice.

CONCLUSIONS

Oral BV administration appears to prevent allergic inflammation by enhancing Treg cell proliferation and acetate production in an asthmatic mouse model.

A Survey of Airborne Fungi and Their Sensitization Profile in Wuhan, China

INTRODUCTION

Airborne fungi induce allergic symptoms in 3-10% of the population worldwide. To better prevent and manage fungi-related allergic diseases, it is essential to identify the genus and the distribution profile of airborne fungi.

METHODS

With this purpose in mind, we carried out a 12-month volumetric sampling study to monitor the airborne fungi and retrospectively analyzed the sensitization profile of four dominant fungi (Cladosporium, Alternaria, Aspergillus, and Penicillium) among respiratory allergies during the same study period in Wuhan, China.

RESULTS

A total of 29 different fungal genuses were identified, and the peak fungal concentration period was found to be in September and October, followed by May and June. The most prevalent fungi in this area were Cladosporium (36.36%), Ustilago (20.12%), and Alternaria (13.87%). In addition, the skin prick test data from 1,365 respiratory allergies patients showed that 202 (14.80%) of them were sensitized to fungi. The sensitization rates to Cladosporium, Alternaria, Aspergillus, and Penicillium were 11.72%, 4.69%, 1.98%, and 4.76%, respectively. The seasonal fluctuation of Alternaria and Aspergillus correlated with their sensitization rates. Among the fungal sensitized patients, 76 (37.62%) were sensitized to two or more kinds of fungi. The serum-specific IgE tests suggested low to high correlations existed between these fungi; however, these correlations were not found between fungi and other allergens.

CONCLUSION

Our study provides the distribution profile and reveals the clinical significance of the airborne fungi in Wuhan, which will facilitate the precise management of fungal allergy.

Maternal high-fat diet increases airway sensory innervation and reflex bronchoconstriction in adult offspring

Children born to obese mothers are prone to develop asthma and airway hyperresponsiveness, but the mechanisms behind this are unclear. Here we developed a mouse model of maternal diet-induced obesity that recapitulates metabolic abnormalities seen in humans born to obese mothers. Offspring of dams fed a high-fat diet (HFD) showed increased adiposity, hyperinsulinemia, and insulin resistance at 16 wk of age despite being fed only a regular diet (RD). Bronchoconstriction induced by inhaled 5-hydroxytriptamine was also significantly increased in offspring of HFD-fed versus RD-fed dams. Increased bronchoconstriction was blocked by vagotomy, indicating this reflex was mediated by airway nerves. Three-dimensional (3-D) confocal imaging of tracheas collected from 16-wk-old offspring showed that both epithelial sensory innervation and substance P expression were increased in the offspring of HFD-fed dams compared with offspring of RD-fed dams. For the first time, we show that maternal high-fat diet increases airway sensory innervation in offspring, leading to reflex airway hyperresponsiveness.NEW & NOTEWORTHY Our study reveals a novel potential mechanism, by which maternal high-fat diet increases the risk and severity of asthma in offspring. We found that exposure to maternal high-fat diet in mice leads to hyperinnervation of airway sensory nerves and increased reflex bronchoconstriction in offspring fed a regular diet only. These findings have important clinical implications and provide new insights into the pathophysiology of asthma, highlighting the need for preventive strategies in this patient population.

Distinct Epithelial-Innate Immune Cell Transcriptional Circuits Underlie Airway Hyperresponsiveness in Asthma

Rationale: Indirect airway hyperresponsiveness (AHR) is a highly specific feature of asthma, but the underlying mechanisms responsible for driving indirect AHR remain incompletely understood. Objectives: To identify differences in gene expression in epithelial brushings obtained from individuals with asthma who were characterized for indirect AHR in the form of exercise-induced bronchoconstriction (EIB). Methods: RNA-sequencing analysis was performed on epithelial brushings obtained from individuals with asthma with EIB (n = 11) and without EIB (n = 9). Differentially expressed genes (DEGs) between the groups were correlated with measures of airway physiology, sputum inflammatory markers, and airway wall immunopathology. On the basis of these relationships, we examined the effects of primary airway epithelial cells (AECs) and specific epithelial cell-derived cytokines on both mast cells (MCs) and eosinophils (EOS). Measurements and Main Results: We identified 120 DEGs in individuals with and without EIB. Network analyses suggested critical roles for IL-33-, IL-18-, and IFN-γ-related signaling among these DEGs. IL1RL1 expression was positively correlated with the density of MCs in the epithelial compartment, and IL1RL1, IL18R1, and IFNG were positively correlated with the density of intraepithelial EOS. Subsequent ex vivo modeling demonstrated that AECs promote sustained type 2 (T2) inflammation in MCs and enhance IL-33-induced T2 gene expression. Furthermore, EOS increase the expression of IFNG and IL13 in response to both IL-18 and IL-33 as well as exposure to AECs. Conclusions: Circuits involving epithelial interactions with MCs and EOS are closely associated with indirect AHR. Ex vivo modeling indicates that epithelial-dependent regulation of these innate cells may be critical in indirect AHR and modulating T2 and non-T2 inflammation in asthma.

[Risk factors for the development of airway hyperresponsiveness in patients with allergic rhinitis]

Allergic rhinitis（AR） is an independent risk factor for allergic asthma. Some AR patients may have developed airway hyperresponsiveness（AHR） in the absence of asthma symptoms. In this stage, AHR is often neglected due to the absence of typical asthma symptoms. Exploring the clinically relevant risk factors for AHR in patients with AR, as well as the clinical indicators and biomarkers to predict AHR in patients with AR, is of great significance to the prevention of the occurrence of AHR and asthma. This review summarized the risk factors for the development of AHR in AR patients, and gave hints to the prevention of AHR in AR patients.

Delayed Microbial Maturation Durably Exacerbates Th17-driven Asthma in Mice

Microbial maturation disrupted by early-life dysbiosis has been linked with increased asthma risk and severity; however, the immunological mechanisms underpinning this connection are poorly understood. We sought to understand how delaying microbial maturation drives worsened asthma outcomes later in life and its long-term durability. Drinking water was supplemented with antibiotics on Postnatal Days 10-20. To assess the immediate and long-term effects of delaying microbial maturation on experimental asthma, we initiated house dust mite exposure when bacterial diversity was either at a minimum or had recovered. Airway hyperresponsiveness, histology, pulmonary leukocyte recruitment, flow cytometric analysis of cytokine-producing lymphocytes, and assessment of serum IgG1 (Immunoglobulin G1) and IgE (Immunoglobulin E) concentrations were performed. RT-PCR was used to measure IL-13 (Interleukin 13)-induced gene expression in sequentially sorted mesenchymal, epithelial, endothelial, and leukocyte cell populations from the lung. Delayed microbial maturation increased allergen-driven airway hyperresponsiveness and Th17 frequency compared with allergen-exposed control mice, even when allergen exposure began after bacterial diversity recovered. Blockade of IL-17A (Interleukin 17A) reversed the airway hyperresponsiveness phenotype. In addition, allergen exposure in animals that experienced delayed microbial maturation showed signs of synergistic signaling between IL-13 and IL-17A in the pulmonary mesenchymal compartment. Delaying microbial maturation in neonates promotes the development of more severe asthma by increasing Th17 frequency, even if allergen exposure is initiated weeks after microbial diversity is normalized. In addition, IL-17A-aggravated asthma is associated with increased expression of IL-13-induced genes in mesenchymal, but not epithelial cells.

Lacticaseibacillus paracasei GM-080 Ameliorates Allergic Airway Inflammation in Children with Allergic Rhinitis: From an Animal Model to a Double-Blind, Randomized, Placebo-Controlled Trial

Background: Probiotics may facilitate the clinical management of allergic diseases. However, their effects on allergic rhinitis (AR) remain unclear. We examined the efficacy and safety of Lacticaseibacillus paracasei GM-080 in a mouse model of airway hyper-responsiveness (AHR) and in children with perennial AR (PAR) by using a double-blind, prospective, randomized, placebo-controlled design. Methods: The production of interferon (IFN)-γ and interleukin (IL)-12 was measured by using an enzyme-linked immunosorbent assay. GM-080 safety was evaluated via the whole-genome sequencing (WGS) of virulence genes. An ovalbumin (OVA)-induced AHR mouse model was constructed, and lung inflammation was evaluated by measuring the infiltrating leukocyte content of bronchoalveolar lavage fluid. A clinical trial was conducted with 122 children with PAR who were randomized to receive different doses of GM-080 or the placebo for 3 months, and their AHR symptom severity scores, total nasal symptom scores (TNSSs), and Investigator Global Assessment Scale scores were examined. Results: Among the tested L. paracasei strains, GM-080 induced the highest IFN-γ and IL-12 levels in mouse splenocytes. WGS analysis revealed the absence of virulence factors or antibiotic-resistance genes in GM-080. The oral administration of GM-080 at 1 × 10⁷ colony forming units (CFU)/mouse/day for 8 weeks alleviated OVA-induced AHR and reduced airway inflammation in mice. In children with PAR, the oral consumption of GM-080 at 2 × 10⁹ CFU/day for 3 months ameliorated sneezing and improved Investigator Global Assessment Scale scores significantly. GM-080 consumption led to a nonsignificant decrease in TNSS and also nonsignificantly reduced IgE but increased INF-γ levels. Conclusion: GM-080 may be used as a nutrient supplement to alleviate airway allergic inflammation.

Treatment with Helicobacter pylori-derived VacA attenuates allergic airway disease

Background

Asthma is an incurable heterogeneous disease with variations in clinical and underlying immunological phenotype. New approaches could help to support existing therapy concepts. Neonatal infection of mice with Helicobacter pylori or administration of H. pylori-derived extracts or molecules after birth have been shown to prevent the development of allergic airway disease later in life. This study evaluated the potential therapeutic efficacy of H. pylori vacuolating cytotoxin A (VacA) in allergic airway inflammation and investigated the underlying immunological mechanisms for its actions.

Methods

Murine models of allergic airway diseases, and murine and human in vitro models were used.

Results

In both an acute model and a therapeutic house dust mite model of allergic airway disease, treatment with H. pylori-derived VacA reduced several asthma hallmarks, including airway hyperresponsiveness, inflammation and goblet cell metaplasia. Flow cytometry and ELISA analyses revealed induction of tolerogenic dendritic cells (DC) and FoxP3 positive regulatory T cells (Tregs), and a shift in the composition of allergen-specific immunoglobulins. Depletion of Tregs during treatment with VacA reversed treatment-mediated suppression of allergic airway disease. Human monocyte derived DCs (moDC) that were exposed to VacA induced Tregs in co-cultured naïve autologous T cells, replicating key observations made in vivo.

Conclusion

H. pylori-derived VacA suppressed allergic airway inflammation via induction of Tregs in both allergic airway disease models. These data suggest that the immunomodulatory activity of VacA could potentially be exploited for the prevention and treatment of allergic airway disease.

Rno_circRNA_008646 regulates formaldehyde induced lung injury through Rno-miR-224 mediated FOXI1/CFTR axis

Formaldehyde (FA) serves as a prevailing air pollutant, which has seriously threatened public health in recent years. Of all the known health effects, lung injury is one of the most severe risks. However, little is known about the circRNAs related molecular mechanism in the development of lung injury induced by FA. This study was designed to explore the potential roles of dysregulated circRNAs as well as its mechanism in FA-induced lung injury. In the present study, 24 male SD rats were exposed to formaldehyde (control, 0.5, 2.46 and 5 mg/m³) for 8 h per day for 8 weeks to induce lung injury. We used H&E staining to evaluate the histopathological changes of lung injury indifferent groups. The expression of circRNAs in lung tissue was detected by real-time PCR. Meanwhile, circRNA/miRNA/mRNA interaction networks were predicted by bioinformatics analysis. Our study revealed that formaldehyde exposure resulted in abnormal histopathological changes in lung tissues. Moreover, the expression of rno_circRNA_008646 was significantly higher in lung tissues of formaldehyde exposure rats than in control. Bioinformatics analysis showed that one potential target miRNA/mRNA for rno_circRNA_008646 was rno-miR-224/Forkhead Box I1 (FOXI1). Besides, luciferase report gene confirmed that there was targeted binding relationship between rno_circRNA_008646 and rno-miR-224, rno-miR-224 and FOXI1. Further verification experiments indicated that the expression of rno_circRNA_008646 was negatively correlated rno-miR-224, while it was positively correlated with FOXI1. JASPAR database showed transcription factor FOXI1 located in promotor of CF Transmembrane Conductance Regulator (CFTR). Both FOXI1 and CFTR were up-regulated in lung tissues after formaldehyde exposure. In conclusion, our findings suggested that formaldehyde may induce lung injury, and this may be caused by up-regulatedrno_circRNA_008646, which medicated rno-miR-224/FOXI1/CFTR axis.

Ambient ozone, and urban PM2.5 co-exposure, aggravate allergic asthma via transient receptor potential vanilloid 1-mediated neurogenic inflammation

Allergic asthma is the most common pulmonary inflammatory disease, and epidemiological studies have revealed that PM_2.5 or ambient ozone (O₃) exposure contribute to the higher prevalence of allergic asthma. Current experimental evidence focus principally on the pathogenic effect of exposure to a single air pollutant, ignoring the possible synergistic effect of combined exposure to a mix of these pollutants, which is a more realistic scenario. In this study, allergic mice and a nociceptor antagonist were used to explore the mechanisms of co-exposure to these two important air pollutants. Compared with exposure to either PM_2.5 or O₃, combined exposure to both greatly aggravated allergic asthma in a dose dependent manner, including increased airway hyperresponsiveness, goblet cell metaplasia, more severe airway inflammation and higher oxidative stress levels. In addition, co-exposure in the allergic mice resulted in elevation of the expression of transient receptor potential vanilloid 1 (TRPV1), and of the production of substance P (SP), which exacerbated lung inflammation by neurogenic inflammation. TRPV1 antagonist (capsazepine, CPZ) treatment for the co-exposed allergic mice, markedly attenuated TRPV1 expression and SP release, and reduced airway inflammation and oxidative damage, further alleviating airway hyperresponsiveness. We conclude that neuro-immune interactions might be involved in PM_2.5 and O₃ co-exposure aggravated allergic asthma.

Evaluation of formaldehyde exposure among gross dissection after modified embalming solution and health assessment

Mainly embalming fixative contains formaldehyde which is classified as a carcinogen. People who work with cadavers have been at higher risk of cancer after formaldehyde exposure. We have formulated a less-formalin fixative (contained 3.6% formaldehyde,23.8% ethanol, 15% glycerin, and 0.2% phenol in the water) for preserving cadavers. Therefore, the objective of the present study was to evaluate the level of atmospheric formaldehyde indoors and the breathing exposure of medical students during dissection classes. We also analyzed the pulmonary parameters and effects of formaldehyde. The levels of atmospheric formaldehyde indoors and personal breathing exposure were sampled during anatomy dissection classes (musculoskeletal system, respiratory system, and abdominopelvic organ system) using sorbent tubes with air sampling pumps. Samples were then analyzed using Gas Chromatography with Flame Ionization Detector (GC-FID). The mean level of formaldehyde indoor air among the three classes was 0.518 ± 0.156 ppm whereas the formaldehyde level in the personal breathing zone was 0.956±0.408 ppm, which exceeded the recommended exposure standards of international agencies, including NIOSH agency and PEL of Thailand legislation. The laboratory had high humidity, high room temperature, and poor air ventilation. There was a significant difference in FVC, FEV1, and PEF (p < 0.05) between the sexes of students. Comparison pulmonary parameters between students and instructors showed that all parameters of the pulmonary function test had no significant differences. General fatigue and burnings of eyes and nose associated with strong odor were the most common symptoms reported during the dissection classes. The modified embalming fixative was used less formalin with ethanol-glycerin mixture, and it was suitable for the study of medical students, with few side effects of respiratory problems. However, the modified exhaust ventilation with local table-exhaust ventilation and heating-ventilation-air conditioning system performance were urgent issues for reducing levels of formaldehyde indoor air in the dissection room.

Semen Quality Following Long-term Occupational Exposure to Formaldehyde in China

IMPORTANCE

The potential effects of long-term occupational exposure to formaldehyde (FA) on human semen quality is not clear.

OBJECTIVE

To assess whether long-term occupational exposure to FA is associated with semen quality.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study was conducted from June 1 to June 30, 2021, in Xi'an, China. Participants were adults aged 23 to 40 years who had lived in the study area for 24 months or longer. Data analysis was performed from September 1 to October 1, 2021.

EXPOSURES

Long-term occupational exposure to FA was measured using a formaldehyde detector, and the FA exposure index (FEI) was calculated as follows: FEI = final concentration of FA (mg/m3) × work time during a workday (hour) × cumulative workdays (year).

MAIN OUTCOMES AND MEASURES

Semen samples were collected by masturbation after 3 to 7 days of abstinence and were then assessed by the computer-automated semen analysis system, Baso-Papanicolaou staining, and sperm-chromatin structure assay.

RESULTS

A total of 205 men (mean [SD] age, 29.49 [3.64] years), with 124 individuals in the FA exposure group (mean [SD] FEI, 73.72 [54.86]) and 81 age-matched controls, were included in the final analysis. Long-term personal occupational exposure to FA was significantly associated with poor semen quality. Specifically, a 1-unit increase in FEI was associated with a change of -0.99% (95% CI, -1.00% to -0.98%) in total sperm motility, -0.99% (95% CI, -0.99% to -0.97%) in progressive sperm motility, -0.05% (95% CI, -0.08% to -0.02%) in curvilinear velocity, -0.07% (95% CI, -0.10% to -0.04%) in straight line velocity, -0.07% (95% CI, -0.10% to -0.04%) in time-average velocity, -0.98% (95% CI, -0.99% to -0.93%) in normal sperm morphology, -0.24% (95% CI, -0.35% to -0.11%) in seminal neutral glucosidase, -0.61% (95% CI, -0.66% to -0.56%) in seminal plasma zinc, 0.52% (95% CI, 0.15% to 1.02%) in beat cross frequency, and 0.10% (95% CI, 0.06% to 0.14%) in the DNA fragmentation index. These associations remained significant after adjusting for confounding factors. Furthermore, subgroup analysis found that high levels of oxidative stress might promote the associations between FA exposure and semen quality.

CONCLUSIONS AND RELEVANCE

This study found an association between long-term occupational exposure to FA and semen quality. This deterioration was dose and time dependent and might be induced by oxidative stress.

Assessment of formaldehyde exposures under contemporary embalming conditions in U.S. funeral homes

The funeral service profession has used formaldehyde-containing embalming solutions for the preparation of decedents since the early 1900s. The available literature regarding funeral director exposure to formaldehyde largely consists of data collected prior to 2000, with most studies reporting task-length exposure concentrations rather than full-shift time-weighted average concentrations. As formaldehyde undergoes review in the U.S. Environmental Protection Agency Toxic Substances Control Act (TSCA) risk evaluation process, accurately characterizing long-term exposure potential in this profession is critical. This study presents passive badge sampling and air change rate measurement results conducted at 13 funeral home locations across the United States. Full-shift (approximately 8-hr) samples were collected on one embalmer per day in each funeral home and on one occupational non-user (ONU), e.g., a receptionist. Additionally, task-length samples were collected during each embalming that occurred during the shift, were one to occur. Full-shift concentrations ranged from 0.007 to 1.1 ppm and 0.007 to 0.042 ppm for embalmers and ONUs, respectively. Task-length formaldehyde concentrations ranged from 0.058 to 1.4 ppm, with the average embalming taking 72.8 min to complete. Air change rates in the preparation rooms ranged from 2.8 to 28.3 air changes per hour; however, no correlation between task-length formaldehyde concentrations and air change rate was observed. Following empirical data collection, a Monte Carlo analysis of estimated annual 8-hr time-weighted average (TWA) exposure was conducted to determine the potential exposure distribution for embalmers employed at private funeral homes. Inputs to the simulation were derived from responses to a National Funeral Directors Association survey and from empirical measurements collected during the study. With respect to the reconstructed 8-hr TWAs, the median 8-hr TWA was 0.037 ppm, with 93.6% of the predicted concentrations below 0.1 ppm. This study provides a robust characterization of contemporary formaldehyde exposures in the funeral service profession. Further, it provides a strategy for interpreting the results along with surveyed responses regarding embalming frequency to better inform risks associated with formaldehyde exposure in this profession.

Toxicological Mechanism of Individual Susceptibility to Formaldehyde-Induced Respiratory Effects

Understanding the mechanisms of individual susceptibility to exposure to environmental pollutants has been a challenge in health risk assessment. Here, an integrated approach combining a CRISPR screen in human cells and epidemiological analysis was developed to identify the individual susceptibility to the adverse health effects of air pollutants by taking formaldehyde (FA) and the associated chronic obstructive pulmonary disease (COPD) as a case study. Among the primary hits of CRISPR screening of FA in human A549 cells, HTR4 was the only gene genetically associated with COPD susceptibility in global populations. However, the association between HTR4 and FA-induced respiratory toxicity is unknown in the literature. Adverse outcome pathway (AOP) network analysis of CRISPR screen hits provided a potential mechanistic link between activation of HTR4 (molecular initiating event) and FA-induced lung injury (adverse outcome). Systematic toxicology tests (in vitro and animal experiments) were conducted to reveal the HTR4-involved biological mechanisms underlying the susceptibility to adverse health effects of FA. Functionality and enhanced expression of HTR4 were required for susceptibility to FA-induced lung injury, and FA-induced epigenetic changes could result in enhanced expression of HTR4. Specific epigenetic and genetic characteristics of HTR4 were associated with the progression and prevalence of COPD, respectively, and these genetic risk factors for COPD could be potential biomarkers of individual susceptibility to adverse respiratory effects of FA. These biomarkers could be of great significance for defining subpopulations susceptible to exposure to FA and reducing uncertainty in the next-generation health risk assessment of air pollutants. Our study delineated a novel toxicological pathway mediated by HTR4 in FA-induced lung injury, which could provide a mechanistic understanding of the potential biomarkers of individual susceptibility to adverse respiratory effects of FA.

Endoplasmic reticulum stress in airway hyperresponsiveness

Airway hyperresponsiveness(AHR) is a major clinical phenomenon in lung diseases (asthma, COPD and pulmonary fibrosis) and not only a high-risk factor for perioperative airway spasm leading to hypoxaemia, haemodynamic instability and even "silent lung", but also a potential risk for increased mortality from underlying diseases (e.g. asthma, COPD). Airway reactivity is closely linked to airway inflammation, remodelling and increased mucus secretion, and endoplasmic reticulum stress is an important mechanism for the development of these pathologies. This review, therefore, focuses on the effects of endoplasmic reticulum stress on the immune cells involved in airway hyperreactivity (epithelial cells, dendritic cells, eosinophils and neutrophils) in inflammation and mucus & sputum secretion; and on the differentiation and remodelling of airway smooth muscle cells and epithelial cells. The aim is to clarify the mechanisms associated with endoplasmic reticulum stress in airway hyperresponsiveness and to find new ideas and methods for the prevention of airway hyperresponsiveness in the perioperative period.

Fisetin Suppresses the Inflammatory Response and Oxidative Stress in Bronchial Epithelial Cells

Fisetin is isolated from many fruits and vegetables and has been confirmed to improve airway hyperresponsiveness in asthmatic mice. However, whether fisetin reduces inflammatory response and oxidative stress in bronchial epithelial cells is unclear. Here, BEAS-2B human bronchial epithelial cells were treated with various concentrations of fisetin and then stimulated with tumor necrosis factor-α (TNF-α) or TNF-α/interleukin-4. In addition, ovalbumin-sensitized mice were treated with fisetin to detect inflammatory mediators and oxidative stress expression. Fisetin significantly reduced the levels of inflammatory cytokines and chemokines in TNF-α-stimulated BEAS-2B cells. Fisetin also attenuated intercellular adhesion molecule-1 expression in TNF-α-stimulated BEAS-2B cells, suppressing THP-1 monocyte adhesion. Furthermore, fisetin significantly suppressed airway hyperresponsiveness in the lungs and decreased eosinophil numbers in the bronchoalveolar lavage fluid of asthmatic mice. Fisetin decreased cyclooxygenase-2 expression, promoted glutathione levels, and decreased malondialdehyde levels in the lungs of asthmatic mice. Our findings indicate that fisetin is a potential immunomodulator that can improve the pathological features of asthma by decreasing oxidative stress and inflammation.

Singlet oxygen -derived nerve growth factor exacerbates airway hyperresponsiveness in a mouse model of asthma with mixed inflammation

BACKGROUND

Refractory asthma, which is caused by several factors including neutrophil infiltration is a serious complication of bronchial asthma. We previously reported that nerve growth factor (NGF) is involved in AHR. NGF-derived induction of hyperalgesia is dependent on neutrophils; however, this relationship remains unclear in respiratory disease. In this study, we examined the roles of neutrophils and NGF in refractory asthma.

METHODS

Using intranasal house dust mite sensitization, we established a mouse model of asthma with mixed inflammation (Mix-in). AHR, NGF production and hyperinnervation of the lungs were examined with or without different inhibitory treatments. The levels of the singlet oxygen markers, 10- and 12-(Z,E)-hydroxyoctadecadienoic acids (HODE) in the lungs, were measured by liquid chromatography-tandem mass spectrometry. An in vitro experiment was also performed to evaluate the direct effect of singlet oxygen on NGF production.

RESULTS

NGF production and hyperinnervation were higher in Mix-in mice than in conventional eosinophilic-asthmatic mice and were positively correlated with AHR. Asthmatic parameters were inhibited by NGF neutralizing Abs and myeloperoxidase (MPO) inhibition. The 10- and 12-(Z,E)-HODEs levels were increased in the lungs and were positively correlated with MPO activity and NGF production. NGF was produced by bronchial epithelial cells in vitro upon stimulation with singlet oxygen.

CONCLUSIONS

Our findings suggest that neutrophil MPO-derived singlet oxygen induces increased NGF production, leading to AHR and 10- and 12-(Z,E)-HODEs production. These findings may help to develop new therapies targeting this mechanism and to establish a new biomarker for non-type 2 and refractory asthma.

Measurement of Airway Hyperresponsiveness in Mice

Asthma has been the most prevalent chronic respiratory disease (Mensah et al. J Allergy Clin Immunol 142:744-748, 2018). To explore pathogenic mechanism or new treatments of asthma, mice have been utilized to model the disease. Eosinophilic airway inflammation, allergen specific-IgE, and airway hyperresponsiveness have been characteristic features of allergic asthma (Drake et al. Pulm Ther 5:103-115, 2019). In mouse models, airway hyperresponsiveness to inhaled broncho-constrictor agents such as methacholine chloride (MCh) has been a key disease marker (Alessandrini et al. Front Immunol 11:575936, 2020). A variety of systems to assess airway reactivity in mice are currently available. Here, three distinct systems are described as these have been used in many publications. In the first system, an invasive system in which mice are anesthetized and intubated followed by mechanical ventilation, lung resistance (R), dynamic compliance (C), and other respiratory parameters with MCh challenge are measured. In the second system, a noninvasive system equipped with a chamber in which mice can move freely and spontaneously breathe, changes in airways with MCh challenge are measured as enhanced pause (Penh) values. In the third system, in vitro airway smooth muscle (ASM) reactivity is monitored in an extracted mouse tracheal duct with a cholinergic agonist challenge or electrical stimulation. Each of these systems has unique features, benefits, or disadvantages.

Occupational scenarios and exposure assessment to formaldehyde: A systematic review

The objectives of the systematic review were to: identify the work sectors at risk for exposure to formaldehyde; investigate the procedures applied to assess occupational exposure; evaluate the reported exposure levels among the different settings. An electronic search of Pubmed, Scopus, Web of Science and ToxNet was carried out for collecting all the articles on the investigated issue published from January 1, 2004 to September 30, 2019. Forty-three papers were included in the review, and evidenced a great number of occupational scenarios at risk for formaldehyde exposure. All the included studies collected data on formaldehyde exposure levels by a similar approach: environmental and personal sampling followed by chromatographic analyses. Results ranged from not detectable values until to some mg m^-3 of airborne formaldehyde. The riskiest occupational settings for formaldehyde exposure were the gross anatomy and pathology laboratories, the hairdressing salons and some specific productive settings, such as wooden furniture factories, dairy facilities and fish hatcheries. Notice that formaldehyde, a well-known carcinogen, was recovered in air at levels higher than outdoor in almost all the studied scenarios/activities; thus, when formaldehyde cannot be removed or substituted, targeted strategies for exposure elimination or mitigation must be adopted.

Inhibiting ATG5 mediated autophagy to regulate endoplasmic reticulum stress and CD4+ T lymphocyte differentiation: Mechanisms of acupuncture's effects on asthma

OBJECTIVE

Asthma is characterized by airway hyperresponsiveness(AHR), inflammation and remodeling. Autophagy and endoplasmic reticulum stress(ERS) are dysregulated in asthma, and ATG5 has attracted wide attentions a representative gene of autophagy. Previous evidence shows that acupuncture may treat asthma by regulating the immune environment.However,the precise mechanism involved in acupuncture's effects on asthma is unclear. Thus, we investigated the inner-relationships of acupuncture and ATG5-mediated autophagy, ERS and CD4+ T lymphocyte differentiation in asthma.

METHODS

Ovalbumin (OVA)-sensitized and challenged ATG5+/- and ATG5-/-mice with asthma were treated by acupuncture at Dazhui(GV14),Feishu(BL13) and Zusanli(ST36),and sacrificed the next day.Then blood and bronchoalveolar lavage fluid (BALF)samples were collected to determine inflammatory cell counts and cytokine levels. Lung tissue samples were obtained for histological examination, and the spleen was harvested for flow cytometry.

RESULTS

Compared with the untreated group, acupuncture decreased BALF inflammatory cell counts and AHR in OVA-induced mice.Acupuncture decreased autophagy-related protein and mRNA (ATG5,Beclin-1,p62 and LC3B)amounts and ERS-related protein (p-PERK, p-IRE-1,Grp78, and ATF6)levels as well as autophagosome formation in lung tissue, concomitant with increased IFN-γ and decreased IL-4, IL-17 and TGF-β amounts in BALF.Consistently, the imbalance of CD4+ T lymphocyte subsets(Th1/Th2 and Treg/Th17) was also corrected by acupuncture.Meanwhile, AHR and inflammation were decreased in ATG5-/- mice compared with ATG+/-animals,without affecting the therapeutic effect of acupuncture.

CONCLUSION

Acupuncture reduces airway inflammation and AHR in asthma by inhibiting ATG5-mediated autophagy to regulate endoplasmic reticulum stress and CD4+T lymphocyte differentiation.

Formaldehyde exposure and atmospheric biomonitoring with lichen Cladonia verticillaris in an anatomy laboratory

Formaldehyde is one of the most toxic contaminants of indoor environments and very common in the anatomy laboratory. In this work, we investigated the level of formaldehyde exposure to staff and students who attended an anatomy lab and in nearby environments in the same university building. We also performed atmospheric biomonitoring of the sites with the lichen Cladonia verticillaris. Quantification samplings were performed over four weeks, on 7 days with and 7 days without practical classes, totaling 70 samples. The samples were collected in five different locations, three points inside the laboratory and two points outside the laboratory, representing nearby and susceptible environments to contamination. The results showed CHOH concentrations from 0.20-3.76 ppmv for days with practical courses and 0.17-3.06 ppmv for days without practical classes. Although the laboratory was more contaminated than the surrounding environments, the concentration of formaldehyde in these areas is not negligible, showing a dispersion of formaldehyde from the laboratory. Potential dose (PD) and cancer risk (CR) were calculated for an individual exposed to the same levels analyzed for 8 h daily and 30 years of work. The study on C. verticillaris lasted 90 days and evaluated the variation of chlorophyll and pheophytin (photosynthetic pigments). The results showed a significant difference in the production of chlorophylls a and b and total chlorophyll when compared to control, and there was also a progressive increase of the total pheophytin/total chlorophyll ratio. The results also showed the correlation between the increase in chlorophylls and the studied environments with less ventilation since these places provided greater accumulation of formaldehyde in the long run. Thus, measurable evidence was obtained of biological disorders in a living organism caused by exposure to formaldehyde.

Arterial stiffness and carotid distensibility following acute formaldehyde exposure in female adults

Formaldehyde (FA) is a ubiquitous organic preservative used in several industries and represents an occupational health hazard. Short-term exposure to FA can increase oxidative stress and cause a decrease in conduit vessel function. These decrements in vascular function may extend to the arterial architecture, predisposing individuals to increased risk of cardiovascular disease. The purpose of this study was to investigate the impact of an acute 90-minute FA exposure period (259 ± 95 ppb) on indices of arterial architecture. Arterial stiffness and carotid distensibility as determined by central pressures, augmentation index (AIx), and carotid-femoral pulse wave velocity (cfPWV) (n=13F, 24 ± 1 year) as well as carotid stiffness and intima media thickness (IMT) (n = 9F, 23 ± 1 year) were assessed prior to (Pre-FA) and immediately following (Post-FA) exposure to FA in human cadaver dissection laboratories. Central pressures and cfPWV (Pre-FA: 5.2 ± 0.8 m.s^-1, Post-FA: 5.2 ± 1.1 m s^-1) were unchanged by acute FA exposure (p > 0.05). Carotid stiffness parameters and distension were unchanged by acute FA exposure (p > 0.05), although distensibility (Pre-FA: 33.9 ± 10.5[10-3*kPa^-1], Post-FA: 25.9 ± 5.5[10-3*kPa-1], p < 0.05), and IMT (Pre-FA: 0.42 ± 0.05 mm, Post-FA: 0.51 ± 0.11 mm, p < 0.05) decreased and increased, respectively. Individual Pre- to Post-FA changes in these markers of arterial architecture did not correlate with levels of FA exposure ([FA]: 20-473 ppb) (p > 0.05). Our group previously found vascular function decrements following acute FA exposure in human cadaver laboratories; here we found that carotid distensibility and intima media thickness are altered following FA exposure.

Personal formaldehyde exposure during the transportation of embalmed cadavers

Occupational exposure to the known carcinogen formaldehyde during embalming (the preservation of cadavers) has been well documented. Cadavers may be transported to universities on loan for training medical professionals in human anatomy courses. However, occupational formaldehyde exposure levels associated with the transportation of cadavers have not previously been published. Therefore, the current pilot study examined formaldehyde exposure during this process. Preserved intact cadavers (room temperature or cooled) were loaded into cargo vans at the source (lending) lab, driven to the destination (borrowing) lab, and unloaded. Dissected cadavers (room temperature) were picked up and loaded into the cargo vans at the destination lab and driven to and unloaded at the source lab. Formaldehyde samples were collected in the breathing zone of employees engaged in cadaver transportation and handling. The number of intact cadavers or dissected cadavers in each cargo van ranged from 4 to 13 bodies. Sample collection times associated with cadaver transportation and handling tasks ranged from 15 to 216 min per sample with formaldehyde concentrations up to 1.6 ppm. Median exposure levels during cadaver transportation tasks were (1) 1.4 ppm (intact room temperature cadavers); (2) 0.13 ppm (dissected room temperature cadavers); and (3) 0.018 ppm (intact cooled cadavers). The median exposure during cadaver handling (loading/unloading) was 0.05 ppm. The 8-hr time-weighted averages during cadaver transportation and handling ranged from 0.030 ppm (intact cooled cadavers and dissected room temperature cadavers) to 0.51 ppm (intact room temperature cadavers, and dissected room temperature cadavers), the latter of which exceeded the American Conference of Governmental Industrial Hygienists recommended time-weighted average threshold limit value of 0.1 ppm. It is recommended that cadavers be transported cooled, however not all facilities may have access to or utilize specialized cadaver storage such as a walk-in cooler. Therefore, alternate exposure prevention approaches should also be identified and implemented.

Applying genome-wide CRISPR to identify known and novel genes and pathways that modulate formaldehyde toxicity

Formaldehyde (FA), a ubiquitous environmental pollutant, is classified as a Group I human carcinogen by the International Agency for Research on Cancer. Previously, we reported that FA induced hematotoxicity and chromosomal aneuploidy in exposed workers and toxicity in bone marrow and hematopoietic stem cells of experimental animals. Using functional toxicogenomic profiling in yeast, we identified genes and cellular processes modulating eukaryotic FA cytotoxicity. Although we validated some of these findings in yeast, many specific genes, pathways and mechanisms of action of FA in human cells are not known. In the current study, we applied genome-wide, loss-of-function CRISPR screening to identify modulators of FA toxicity in the human hematopoietic K562 cell line. We assessed the cellular genetic determinants of susceptibility and resistance to FA at 40, 100 and 150 μM (IC10, IC20 and IC60, respectively) at two time points, day 8 and day 20. We identified multiple candidate genes that increase sensitivity (e.g. ADH5, ESD and FANC family) or resistance (e.g. FASN and KDM6A) to FA when disrupted. Pathway analysis revealed a major role for the FA metabolism and Fanconi anemia pathway in FA tolerance, consistent with findings from previous studies. Additional network analyses revealed potential new roles for one-carbon metabolism, fatty acid synthesis and mTOR signaling in modulating FA toxicity. Validation of these novel findings will further enhance our understanding of FA toxicity in human cells. Our findings support the utility of CRISPR-based functional genomics screening of environmental chemicals.

Airway hyperresponsiveness development and the toxicity of PM2.5

Airway hyperresponsiveness (AHR) is characterized by excessive bronchoconstriction in response to nonspecific stimuli, thereby leading to airway stenosis and increased airway resistance. AHR is recognized as a key characteristic of asthma and is associated with significant morbidity. At present, many studies on the molecular mechanisms of AHR have mainly focused on the imbalance in Th1/Th2 cell function and the abnormal contraction of airway smooth muscle cells. However, the specific mechanisms of AHR remain unclear and need to be systematically elaborated. In addition, the effect of air pollution on the respiratory system has become a worldwide concern. To date, numerous studies have indicated that certain concentrations of fine particulate matter (PM2.5) can increase airway responsiveness and induce acute exacerbation of asthma. Of note, the concentration of PM2.5 does correlate with the degree of AHR. Numerous studies exploring the toxicity of PM2.5 have mainly focused on the inflammatory response, oxidative stress, genotoxicity, apoptosis, autophagy, and so on. However, there have been few reviews systematically elaborating the molecular mechanisms by which PM2.5 induces AHR. The present review separately sheds light on the underlying molecular mechanisms of AHR and PM2.5-induced AHR.

Indoor Formaldehyde Concentration, Personal Formaldehyde Exposure and Clinical Symptoms during Anatomy Dissection Sessions, University of Medicine 1, Yangon

The formaldehyde (FA) embalming method, the world's most common protocol for the fixation of cadavers, has been consistently used in medical universities in Myanmar. This study was designed to examine the indoor FA concentrations in anatomy dissection rooms, an exposed site, and lecture theater, an unexposed control site, and to access personal exposure levels of FA and clinical symptoms of medical students and instructors. In total, 208 second year medical students (1/2019 batch) and 18 instructors from Department of Anatomy, University of Medicine 1, participated. Thirteen dissection sessions were investigated from February 2019 to January 2020. Diffusive sampling devices were used as air samplers and high-performance liquid chromatography was used for measurement of FA. Average indoor FA concentration of four dissection rooms was 0.43 (0.09-1.22) ppm and all dissection rooms showed indoor concentrations above the occupational exposure limits and short-term exposure limit for general population. Personal FA exposure values were higher than indoor FA concentrations and the instructors (0.68, 0.04-2.11 ppm) had higher exposure than the students (0.44, 0.06-1.72 ppm). Unpleasant odor, eye and nose irritations and inability to concentrate were frequently reported FA-related symptoms, and the students were found to have significantly higher risks (p < 0.05) of having these symptoms during the dissection sessions than during lecture.

Interdisciplinary Significance of Food-Related Adverse Reactions in Adulthood

Background: Adults frequently interpret food-associated adverse reactions as indicators of a food allergy. However, the public perception of food allergy may differ from a clinician's point of view. The prevalence of patient-reported food allergy tends to be higher than physician-confirmed cases. Dermatological manifestations (urticaria, pruritus, dermatitis, and edema) are frequently reported by patients. Objective: The aim of this study was to describe patient-reported symptoms related to suspected food allergies and particularly to characterize and highlight the volume of patients who visit Budapest allergy clinics with suspected food allergies. Methods: In this prospective study, adult (≥18 years) patients were examined at the Allergology Outpatient Unit of the Dept. of Dermatology, Venereology, and Dermatooncology, Semmelweis University, Budapest. The examination included a detailed medical history; physical examination; and when necessary the measurement of allergen-specific serum immunoglobulin E (IgE) levels. Results: Data from 501 patients (393 women, 108 men) were analyzed. Intolerance to dietary biogenic amines occurred in 250 cases (250/501, 50%). Oral allergy syndrome was confirmed in 71 patients (71/501, 14%). Allergy to food preservatives was diagnosed in 14 (14/501, 3%) cases by a dermatologist-allergist specialist. Five individuals (5/501, 1%) were diagnosed with IgE-mediated food allergy. In some cases (28/501, 6%), edema-inducing/enhancing side effects of drugs were observed which patients had misattributed to various foods. Among the food groups considered to be provoking factors, the most frequently mentioned were fruits (198/501, 40%), milk/dairy products (174/501, 35%), and nuts/oilseeds (144/501, 29%). Overwhelmingly, urticaria (47%) was the most common dermatological diagnosis, followed by dermatitis (20%) and allergic contact dermatitis (8%). Conclusion: Improvement is needed in food allergy, food intolerance, and general nutritional knowledge among the general public. According to our data, perceived/self-reported food allergies were overestimated by adults when compared against physician-confirmed food allergies; however, other diseases potentially responsible for food-related problems were underestimated. The prevalence of oral allergy syndrome was high in the cohort. Intolerance to dietary biogenic amines was common, and although the role of dietary histamine and biogenic amine is not entirely understood in eliciting patients' symptoms, improvements in complaints were reported during the control visits.

The relationship between impaired lung functions and cytokine levels in formaldehyde exposure

Exposure to formaldehyde (FA) causes detrimental effects on respiratory system. Inflammation is one of the mechanisms responsible for these effects. Our aim is to demonstrate the possible effect of formaldehyde on inflammation biomarkers and pulmonary function tests. One hundred ninety-eight male workers in a fiber production factory are included. Eighty two of them were not exposed to FA. Thirty nine workers were exposed to FA for 4 h or more in a work shift and 77 workers were exposed less than 4 h. Statistically significant differences were found for FA, TNF-α, and IL-6 levels and pulmonary function test parameters (FEV1 and FVC) between no exposure and exposure groups. The results revealed a correlation between decrement in pulmonary function tests and an increase in cytokine levels concordant with the duration of FA exposure. The results may emphasize that FA exposure shows its effect on pulmonary system via inflammatory pathways.

Intermittent hypercapnic hypoxia induces respiratory hypersensitivity to fentanyl accompanied by tonic respiratory depression by endogenous opioids

KEY POINTS

Sleep apnoea increases susceptibility to opioid-induced respiratory depression (OIRD). Endogenous opioids are implicated as a contributing factor in sleep apnoea. Rats exposed to sleep-phase chronic intermittent hypercapnic hypoxia (CIHH) for 7 days exhibited exaggerated OIRD to systemic fentanyl both while anaesthetized and artificially ventilated and while conscious and breathing spontaneously, implicating heightened CNS inhibitory efficacy of fentanyl. CIHH also induced tonic endogenous opioid suppression of neural inspiration. Sleep-related episodes of hypercapnic hypoxia, as in sleep apnoea, promote hypersensitivity to OIRD, with tonic respiratory depression by endogenous opioids implicated as a potential underlying cause.

ABSTRACT

Sleep apnoea (SA) increases opioid-induced respiratory depression (OIRD) and lethality. To test the hypothesis that this results from chronic intermittent bouts of hypercapnic hypoxia (CIHH) accompanying SA, we compared OIRD across continuously normoxic control rats and rats exposed to sleep-phase (8 h/day) CIHH for 1 week. OIRD sensitivity was first assessed in anaesthetized (urethane/α-chloralose), vagotomized and artificially ventilated rats by recording phrenic nerve activity (PNA) to index neural inspiration and quantify PNA burst inhibition to graded doses (0, 2, 20, 50 μg kg-1 , i.v.) of the synthetic opioid fentanyl. Fentanyl dose-dependently reduced PNA burst frequency (P = 0.0098-0.0001), while increasing the duration of burst quiescence at 50 μg kg-1 (P < 0.0001, n = 5-6/group/dose). CIHH shifted the fentanyl dose-phrenic burst frequency response curve to the left (P = 0.0163) and increased the duration of burst quiescence (P < 0.0001). During fentanyl recovery, PNA burst width was increased relative to baseline in normoxic and CIHH rats. Systemic naloxone (1 mg kg-1 , i.v.) reversed fentanyl-induced PNA arrest in both groups (P = 0.0002), and increased phrenic burst amplitude above baseline (P = 0.0113) in CIHH rats only. Differential sensitivity to anaesthesia as a cause of CIHH-related OIRD hypersensitivity was excluded by observing in conscious spontaneously breathing rats that fentanyl at 20 μg kg-1 (i.v.), which silenced PNA in anaesthetized rats, differentially increased breathing variability in normoxic versus CIHH rats (P = 0.0427), while significantly reducing breathing frequency (P < 0.0001) and periodicity (P = 0.0003) in CIHH rats only. Findings indicate that CIHH increased OIRD sensitivity, with tonic inspiratory depression by endogenous opioids as a likely contributing cause.