Background: Exposure to tobacco or marijuana smoke, or e-cigarette aerosols, causes vascular endothelial dysfunction in humans and rats. We aimed to determine what constituent, or class of constituents, of smoke is responsible for endothelial functional impairment. Methods: We investigated several smoke constituents that we hypothesized to mediate this effect by exposing rats and measuring arterial flow-mediated dilation (FMD) pre- and post-exposure. We measured FMD before and after inhalation of sidestream smoke from research cigarettes containing normal and reduced nicotine level with and without menthol, as well as 2 of the main aldehyde gases found in both smoke and e-cigarette aerosol (acrolein and acetaldehyde), and inert carbon nanoparticles. Results: FMD was reduced by all 4 kinds of research cigarettes, with extent of reduction ranging from 20% to 46% depending on the cigarette type. While nicotine was not required for the impairment, higher nicotine levels in smoke were associated with a greater percent reduction of FMD (41.1±4.5% reduction versus 19.2±9.5%; P =0.047). Lower menthol levels were also associated with a greater percent reduction of FMD (18.5±9.8% versus 40.5±4.8%; P =0.048). Inhalation of acrolein or acetaldehyde gases at smoke-relevant concentrations impaired FMD by roughly 50% ( P =0.001). However, inhalation of inert carbon nanoparticles at smoke-relevant concentrations with no gas phase also impaired FMD by a comparable amount ( P <0.001). Bilateral cervical vagotomy blocked the impairment of FMD by tobacco smoke. Conclusions: There is no single constituent or class of constituents responsible for acute impairment of endothelial function by smoke; rather, we propose that acute endothelial dysfunction by disparate inhaled products is caused by vagus nerve signaling initiated by airway irritation.

MYBPC3, encoding cardiac myosin binding protein-C (cMyBP-C), is the most mutated gene known to cause hypertrophic cardiomyopathy (HCM). However, since little is known about the underlying etiology, additional in vitro studies are crucial to defining the underlying molecular mechanisms. Accordingly, this study aimed to investigate the molecular mechanisms underlying the pathogenesis of HCM associated with a polymorphic variant (D389V) in MYBPC3 by using isogenic human-induced pluripotent stem cell (hiPSC)-derived cardiac organoids (hCOs). The hiPSC-derived cardiomyocytes (hiPSC-CMs) and hCOs were generated from human subjects to define the molecular, cellular, functional, and energetic changes caused by the MYBPC3^D389V variant, which is associated with increased fractional shortening and highly prevalent in South Asian descendants. Recombinant C0-C2, N’ region of cMyBP-C (wild-type and D389V), and myosin S2 proteins were also utilized to perform binding and motility assays in vitro. Confocal and electron microscopic analyses of hCOs generated from noncarriers (NC) and carriers of the MYBPC3^D389V variant revealed the presence of highly organized sarcomeres. Furthermore, functional experiments showed hypercontractility, faster calcium cycling, and faster contractile kinetics in hCOs expressing MYBPC3^D389V than NC hCOs. Interestingly, significantly increased cMyBP-C phosphorylation in MYBPC3^D389V hCOs was observed, but without changes in total protein levels, in addition to higher oxidative stress and lower mitochondrial membrane potential (ΔΨm). Next, spatial mapping revealed the presence of endothelial cells, fibroblasts, macrophages, immune cells, and cardiomyocytes in the hCOs. The hypercontractile function was significantly improved after the treatment of the myosin inhibitor mavacamten (CAMZYOS^®) in MYBPC3^D389V hCOs. Lastly, various vitro binding assays revealed a significant loss of affinity in the presence of MYBPC3^D389V with myosin S2 region as a likely mechanism for hypercontraction. Conceptually, we showed the feasibility of assessing the functional and molecular mechanisms of HCM using highly translatable hCOs through pragmatic experiments that led to determining the MYBPC3^D389V hypercontractile phenotype, which was rescued by the administration of a myosin inhibitor.

Background: Marijuana leaf vaporizers, which heat plant material and sublimate Δ‐9‐tetrahydrocannabinol without combustion, are popular alternatives to smoking cannabis that are generally perceived to be less harmful. We have shown that smoke from tobacco and marijuana, as well as aerosol from e‐cigarettes and heated tobacco products, impair vascular endothelial function in rats measured as arterial flow‐mediated dilation (FMD). Methods and Results: We exposed 8 rats per group to aerosol generated by 2 vaporizer systems (Volcano and handheld Yocan) using marijuana with varying Δ‐9‐tetrahydrocannabinol levels, in a single pulsatile exposure session of 2 s/min over 5 minutes, and measured changes in FMD. To model secondhand exposure, we exposed rats for 1 minute to diluted aerosol approximating release of uninhaled Volcano aerosol into typical residential rooms. Exposure to aerosol from marijuana with and without cannabinoids impaired FMD by ≈50%. FMD was similarly impaired by aerosols from Yocan (237 °C), and from Volcano at both its standard temperature (185 °C) and the minimum sublimation temperature of Δ‐9‐tetrahydrocannabinol (157 °C), although the low‐temperature aerosol condition did not effectively deliver Δ‐9‐tetrahydrocannabinol to the circulation. Modeled secondhand exposure based on diluted Volcano aerosol also impaired FMD. FMD was not affected in rats exposed to clean air or water vapor passed through the Volcano system. Conclusions: Acute direct exposure and modeled secondhand exposure to marijuana leaf vaporizer aerosol, regardless of cannabinoid concentration or aerosol generation temperature, impair endothelial function in rats comparably to marijuana smoke. Our findings indicate that use of leaf vaporizers is unlikely to reduce the vascular risk burden of smoking marijuana.

Background and Objectives. This study proposes a novel urine collection device that can divide each urine collection into 20 parts and store and cool just one part. The aim of the current study is to compare measured biomarkers from the proposed urine collection device to those of conventional 24-hour sampling method. We also hypothesized that the new method would significantly increase patients’ adherence to the timed urine collection.Methods. Two 24-hour urine samples with the conventional method and with the new automated urine collection device that uses just one-twentieth of each void were obtained from 40 healthy volunteers. Urine parameters including volume, creatinine, and protein levels were compared between the two methods and the agreement of two measurements for each subject was reported through Bland-Altman plots.Results. Our results confirmed that for all three variables, there is a positive correlationP<0.001between the two measurements and high degree of agreement could be seen in Bland-Altman plots. Moreover, more subjects reported the new method as “more convenient” for 24-hour urine collection.Conclusions. Our results clearly indicate that a fixed proportion of each void may significantly reduce the urine volume in timed collections and this, in turn, may increase subjects’ adherence to this difficult sampling.