Development of a standardized new cigarette smoke generating (SNCSG) system for the assessment of chemicals in the smoke of new cigarette types (heat-not-burn (HNB) tobacco and electronic cigarettes (E-Cigs))

Development and validation of a method for preparing heated tobacco product aerosol condensate (HTPAC) for large-scale toxicity data acquisition

A method of preparing heated tobacco product aerosol condensate (HTPAC) was developed to expedite HTP toxicity evaluation, and the effectiveness was assessed. To prepare HTPAC, HTP aerosol was generated and collected using a Cambridge filter (particulate phase) and Dulbecco's phosphate buffered saline (DPBS; gaseous phase). The aerosol collected on the Cambridge filter was extracted using methanol, which was thereafter removed by nitrogen purging. The HTP aerosol residue was mixed with DPBS loaded with the collected HTP vapor, ultimately yielding HTPAC. Nicotine and formaldehyde, key harmful compounds in HTP aerosol, were detected in HTPAC (901 ± 224 and 22.2 ± 3.90 µg stick-1, respectively, comparable to those in HTP aerosol (990-1350 (nicotine) and 2.33-21.9 µg stick-1 (formaldehyde)). Propylene glycol and vegetable glycerin, which influence the amount of HTP aerosol, were detected at similar levels in HTPAC and HTP aerosol (propylene glycol = 616 ± 57.1 (HTPAC) and 320-630 µg stick-1 (aerosol) and vegetable glycerin = 2418 ± 224 (HTPAC) and 1667-4000 µg stick-1 (aerosol)). Known components of HTP aerosol (hydroxyacetone, acetic acid, triacetin, and 2-furanmethanol) were also detected in HTPAC. Consequently, HTPAC offers an effective method for concentrating harmful compounds found in HTP aerosols. This, in turn, facilitates comprehensive toxicity assessments, paving the way for guidelines ensuring the safe utilization of HTP.

Protein kinase Cβ is involved in cigarette smoke gas phase-induced ferroptosis in J774 macrophages

Cigarette smoking is a risk factor for respiratory infection caused by immune cell dysfunction. Cigarette smoke is divided into tar and gas phases. Although the gas phase induces cell death in various cell types, the mechanism for gas phase-induced cell death remains to be clarified. In this study, we have examined the effects of cigarette smoke gas phase on J774 macrophages. Cigarette smoke gas phase and cytotoxic factors in the gas phase induced protein kinase C (PKC)-dependent ferroptosis. Pharmacological studies using isoform-specific PKC inhibitors have revealed that PKCβ is involved in cigarette smoke gas phase-induced ferroptosis in J774 macrophages.

The Emission of VOCs and CO from Heated Tobacco Products, Electronic Cigarettes, and Conventional Cigarettes, and Their Health Risk

The differences in aerosol composition between new tobacco types (heated tobacco products and electronic cigarettes) and conventional cigarettes have not been systematically studied. In this study, the emissions of volatile organic compounds (VOCs), carbon monoxide (CO), nicotine, and tar from heated tobacco products (HTPs), electronic cigarettes (e-cigarettes) and conventional cigarettes were compared, and their health risks were evaluated by applying the same smoking regime and a loss mechanism of smoking. Twenty VOCs were identified in aerosols from HTPs, 18 VOCs were identified in aerosols from e-cigarettes, and 97 VOCs were identified in aerosols from cigarettes by GC–MS and HPLC analysis. The concentrations of total VOCs (TVOCs) emitted by the three types of tobacco products decreased as follows: e-cigarettes (795.4 mg/100 puffs) > cigarettes (83.29 mg/100 puffs) > HTPs (15.65 mg/100 puffs). The nicotine content was 24.63 ± 2.25 mg/100 puffs for e-cigarettes, 22.94 ± 0.03 mg/100 puffs for cigarettes, and 8.817 ± 0.500 mg/100 puffs for HTPs. When using cigarettes of the same brand, the mass concentrations of VOCs, tar, and CO emitted by HTPs were approximately 81.2%, 95.9%, and 97.5%, respectively, lower than the amounts emitted by cigarettes. The health risk results demonstrated that the noncarcinogenic risk of the three types of tobacco products decreased as follows: cigarettes (3609.05) > HTPs (2449.70) > acceptable level (1) > e-cigarettes (0.91). The lifetime cancer risk (LCR) decreased as follows: cigarettes (2.99 × 10⁻⁴) > HTPs (9.92 × 10⁻⁵) > e-cigarettes (4.80 × 10⁻⁵) > acceptable level (10⁻⁶). In general, HTPs and e-cigarettes were less harmful than cigarettes when the emission of VOCs and CO was considered.

Fabrication and Properties of Electrospun and Electrosprayed Polyethylene Glycol/Polylactic Acid (PEG/PLA) Films

Polylactic acid (PLA) film is an alternative filter material for heat-not-burn (HNB) tobacco, but its controllability in cooling performance is limited. In this work, polyethylene glycol (PEG) was introduced to form a polyethylene glycol/polylactic acid (PEG/PLA) film by electrospinning or electrospraying techniques to enhance the cooling performance, due to its lower glass transition and melting temperatures. The PEG/PLA films with typical electrospun or electrosprayed morphologies were successfully fabricated. One typical endothermic peak at approximately 65 °C was clearly observed for the melting PEG phase in the heating process, and the re-crystallization temperature represented by an exothermic peak was effectively lowered to 90–110 °C during the cooling process, indicating that the cooling performance is greatly enhanced by the introduction of the PEG phase. Additionally, the wetting properties and adsorption properties were also intensively studied by characterizing the contact angles, and the as-prepared PEG/PLA films all showed good affinity to water, 1,2-propandiol and triglyceride. Furthermore, the PEG/PLA film with a PLA content of 35 wt.% revealed the largest elasticity modulus of 378.3 ± 68.5 MPa and tensile strength of 10.5 ± 1.1 MPa. The results achieved in this study can guide the development of other filter materials for HNB tobacco application.