Pulmonary toxicity of e-cigarettes (e-cigs), particularly their combined effects with occupational exposures like crystalline silica (S), remains largely unexplored. This study evaluated the combined effects, molecular mechanisms, and differential responses in the lungs following co-exposure to e-cig aerosols and S. Subchronic silicosis was established by oropharyngeal aspiration of S (0.2 g/kg) into C57BL/6 mice. Mice were exposed to filtered air, S, or e-cig (E) + S with endpoints evaluated 28 days post-exposure. The count median diameter of e-cig aerosols generated for our mice exposure was 0.771 µm (GSD = 2.33). Enhanced pause (Penh) values increased significantly in male E + S group and female S and E + S groups, compared to their respective air controls, during the first and second weeks of exposure. Histological evaluations (hematoxylin and eosin and Masson’s trichrome staining) revealed significantly increased fibrosis scores in both male and female S and E + S groups compared to respective air controls. Hematological analysis revealed a significant decrease in neutrophil counts/percentage in female E + S mice compared to S alone. Cytokine analysis revealed a significant increase in keratinocyte chemoattractant (KC) levels in male S and E + S groups compared to air controls, while in female mice, KC expression increased significantly in the E + S group compared to S alone. Protein analysis revealed distinct sex-specific changes in key protein markers associated with fibrosis and epithelial-mesenchymal transition. Taken together, these findings indicate that S-induced lung fibrosis with or without e-cig exposure occurred in both male and female mice, with different underlying molecular mechanisms.

Maternal exposure to electronic cigarettes (Ecigs) is found to reduce litter size at birth andweaning in rodents. We have previously observed that febuxostat (a xanthine oxidase inhibitor) mediates recovery of vascular dysfunction in offspring with a history of in utero exposure to Ecigs from maternal vaping while pregnant. In this study, we tested the hypothesis that treatment of febuxostat concomitant with maternal vaping during pregnancy would prevent or mitigate adverse reproductive and/or offspring outcomes. We exposed time-mated pregnant C57Bl/6J mice to Ecig aerosol and febuxostat [Febx in drinking water 50 mg/L] from gestational day (GD)7 until GD21 (birth) and compared maternal/litter health to controls (both no-drug and air exposed, respectively). Daily aerosol concentration (resulting from 60-puffs/d, 17.5 watts, and e-liquid comprising 50:50 (v:v) VG:PG with no flavor or nicotine additive) was assessed and found to be 914±326 mg/m 3 (mean±SD). We observed no differences in maternal weight gain from GD1 to GD21 in Air (83%, n=7), Air+Febx (86%, n=6), Ecig (84%, n=7) and Ecig+Febx (81%, n=8) treated groups. The number of days on Febx treatment was similar in Air+Febx and Ecig+Febx (15.4 and 15.5 days, respectively). The number of uterine implantation sites (observed after weaning) was not different between any of the groups [range of 7-12 implant sites, with group means ranging from 7.2-9.2 (1.7-1.2 SD)]. However, the number of offspring born and the number alive at weaning was different between Febx-treated Air and Ecig groups (ANOVA interaction effect, p<0.05), where maternal Febx-treatment improved the number ofpups surviving at weaning in Ecig (from Ecig 5.8±1.3 to Ecig+Febx 8.0±1.3, p<0.05) but not in Air-exposed dams (from Air 6.8±1.7 to Air+Febx 4.7±3.8, p=ns). Survival at weaning was not different for male and female offspring. Body mass of pups at weaning was significantly lower in both male (-16.5%) and female (-17.4%) offspring in the Ecig+Febx group compared to all other groups (ANOVA p<0.001). These data suggest that XO inhibition during the second trimester may help to mitigate pup mortality seen at birth/weaning in association with maternal vaping. However, caution must be noted since the body mass of offspring in the Ecig+Febx group was lower compared to controls, and the long-term consequences to offspring health due to in utero exposure to febuxostat are not yet known. NIH R56 ES035719-01A1 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Emerging studies find arteriolar dysfunction in offspring with in utero electronic-cigarette (Ecig) exposure, but the long-term effects on offspring's cerebrovascular and neurocognitive health are poorly understood. Ecigs provides a unique opportunity to directly evaluate the contributions of inhaled nicotine from the vehicle e-liquid, which was not possible with cigarettes. Moreover, many Ecigs have variable power settings, which can alter aerosol toxicity. We hypothesize that maternal vaping at different wattages will have variable effects on offspring cerebrovascular function and would be independent of nicotine. We used time-mated female Sprague-Dawley rats with Ecig exposure from gestation day (GD)2 to 21. We studied male and female offspring at 1, 3, 6 and 12 months of age, and found the magnitude of middle cerebral artery (MCA) impairment in offspring was greater at 30 W vs. 5 W, but that both conditions significantly impaired MCA function. Vascular dysfunction was evident with or without nicotine in the e-liquid, but nicotine exposure (50 mg/ml e-liquid) resulted in short-term memory deficits, evidence of neuronal damage, and increased astrocyte interaction with endothelial cells in 6- and 12-month-old offspring. We also observed altered expression of clock genes and antioxidant signalling pathways, along with a decrease in sirtuin-1 expression, a decreased ratio of beta-amyloid (Aβ) 42/40 protein expression, and an increase in NADPH oxidase 1, which are consistent with redox imbalance, neuroinflammation and advancing cellular senescence. These preclinical data provide evidence suggesting that in utero exposure to Ecigs from maternal vaping adversely affects the brain health of offspring in their adult life and that neurocognitive outcomes are worsened with exposure to nicotine. KEY POINTS: Cerebrovascular impairment in offspring with maternal electronic-cigarette (Ecig) exposure is dependent on the wattage of the Ecig device and not the presence of nicotine. While nicotine is not implicated in the aetiology of cerebrovascular impairment, it did contribute to neurocognitive deficits and the severity of neuronal damage. Offspring with Ecig exposure during pregnancy, regardless of wattage or nicotine presence, had decreased sirtuin 1 (SIRT1), elevated NADPH oxidase 1, and exhibited Alzheimer's like pathology. Rodent offspring with in utero exposure to Ecig exhibit long-lasting cerebrovascular and neurocognitive dysfunction into adult life, indicating the vaping during pregnancy is not harmless.

Gastric cancer is the fifth most common cancer and the fifth leading cause of cancer deaths worldwide. Chronic infection by the bacterium Helicobacter pylori is the most prominent gastric cancer risk factor, but only 1-3% of infected individuals will develop gastric cancer. Cigarette smoking is another independent gastric cancer risk factor, and H. pylori-infected smokers are at a 2-11-fold increased risk of gastric cancer development, but the direct impacts of cigarette smoke on H. pylori pathogenesis remain unknown. In this study, male C57BL/6 mice were infected with H. pylori and began smoking within one week of infection. The mice were exposed to cigarette smoke (CS) five days/week for 8 weeks. CS exposure had no notable impact on gross gastric morphology or inflammatory status compared to filtered-air (FA) exposed controls in mock-infected mice. However, CS exposure significantly blunted H. pylori-induced gastric inflammatory responses, reducing gastric atrophy and pyloric metaplasia development. Despite blunting these classic pathological features of H. pylori infection, CS exposures increased DNA damage within the gastric epithelial cells and accelerated H. pylori-induced dysplasia onset in the INS-GAS gastric cancer model. These data suggest that cigarette smoking may clinically silence classic clinical symptoms of H. pylori infection but enhance the accumulation of mutations and accelerate gastric cancer initiation.

Pregnancy is a vulnerable time with significant cardiovascular changes that can lead to adverse outcomes, which can extend into the postpartum window. Exposure to emissions from electronic cigarettes (Ecig), commonly known as “vaping,” has an adverse impact on cardiovascular function during pregnancy and post-natal life of offspring, but the postpartum effects on maternal health are poorly understood. We used a Sprague Dawley rat model, where pregnant dams are exposed to Ecigs between gestational day (GD)2-GD21 to examine postpartum consequences. Litter and dam health were monitored during the weaning period, and maternal vascular and endocrine function were assessed after weaning. Exposure to Ecig emissions during pregnancy led to fetal losses (i.e., reabsorption in utero) and reduced survival of pups during weaning compared to controls (air-exposed dams). We find that maternal vaping during pregnancy, with or without nicotine (or flavoring) results in maternal vascular and hormonal dysfunction (i.e., reduced prolactin, increased expression of sirtuin 1 deacetylase in the brain). Both 5 and 30W Ecig aerosol exposures resulted in significant impairment of middle cerebral artery reactivity to acetylcholine-mediated dilation (decreasing 22 and 50

Emerging evidence indicates maternal electronic cigarette (Ecig) exposure during gestation can cause adverse effects on behavior and brain development. Rodent models show an increase in anxiety like behavior and short-term memory deficits when exposed to Ecig aerosol in utero. Neurons are vital to maintaining brain homeostasis and behavior. We used the 10X Genomics platform for single-nucleus (sn)-RNA sequencing and snATAC sequencing to assess differential gene expression and differences in chromatin openness. Pregnant Sprague Dawley rats were exposed from gestational day 2 to 21 to the base Ecig liquid with 50:50 (v:v) ratio of vegetable glycerin and propylene glycol with no nicotine and no flavorings aerosolized at 5 watts or 30 watts power setting. Differing device power was used to create a cloud density corresponding to low (5w = 163 mg/m 3 ) and high (30w = 917 mg/m 3 ) exposure dose groups. After birth, offspring were aged to 6-months and then brain samples from the cerebral cortex were collected and analyzed. Seven cell types were detected (i.e. inhibitory neurons, excitatory neurons, oligodendrocytes, oligodendrocyte progenitor cells, vasculature associated cells, astrocytes, and microglia) using established cell-specific marker genes. We hypothesized that there would be differences in chromatin accessibility and transcription of excitatory and inhibitory neurons corresponding to behavioral changes in adult (6-month) rat offspring with gestational Ecig exposure compared to controls (i.e. offspring from dams exposed only to ambient air). The threshold |log2 fold change|>1.00 (p-value <0.01) was applied to the differentially expressed genes. Excitatory neuron cluster exhibited 11 upregulated and 154 downregulated genes in the 5 watt exposure group and 977 downregulated genes in the 30 watt group. The inhibitory neuron cluster showed 80 upregulated and 202 downregulated genes in the 5 watt exposure group and 6 upregulated and 949 downregulated genes in the 30 watt group. Gene ontology enrichment analysis (ShinyGo 0.80) revealed there were only a few pathways differentially regulated with Ecigs compared to Air in excitatory neurons. In contrast, changes in gene expression corresponding to multiple neurodegenerative conditions (including Alzheimer's, Prion, and Parkinson disease) were found with inhibitory neurons collected from the 30W exposure group. These data suggest gestational exposure from maternal vaping during pregnancy affects neuronal development in a way which causes long-lasting effects that may increase risk for several neurodegenerative conditions. AHA CSA 20CSA35320107 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Abstract The long‐term consequences of electronic cigarette (Ecig) use in humans are not yet known, but it is known that Ecig aerosols contain many toxic compounds of concern. We have recently shown that Ecig exposure impairs middle cerebral artery (MCA) endothelial function and that it takes 3 days for MCA reactivity to return to normal. However, the sources contributing to impairment of the endothelium were not investigated. We hypothesized that the increased levels of oxidative stress markers in the blood are correlated with impaired MCA reactivity. We used electron paramagnetic resonance (EPR) spectroscopy to examine plasma from 4‐month‐old male Sprague–Dawley rats that were exposed to either air (n = 5) or 1 h Ecig exposure, after which blood samples were collected at varying times after exposure (i.e., 1–4, 24, 48 and 72 h postexposure, n = 4 or 5 in each time group). The EPR analyses were performed using the redox‐sensitive hydroxylamine spin probe 1‐hydroxy‐3‐carboxymethyl‐2,2,5,5‐tetramethyl‐pyrrolidine (CMH) to measure the level of reactive oxidant species in the plasma samples. We found that EPR signal intensity from the CM• radical was significantly increased in plasma at 1‐4, 24 and 48 h (P < 0.05, respectively) and returned to control (air) levels by 72 h. When evaluating the EPR results with MCA reactivity, we found a significant negative correlation (Pearson's P = 0.0027). These data indicate that impaired cerebrovascular reactivity resulting from vaping is associated with the oxidative stress level (measured by EPR from plasma) and indicate that a single 1 h vaping session can negatively influence vascular health for up to 3 days after vaping. Highlights What is the central question of this study? Does the time course of oxidative stress triggered by electronic cigarette exposure follow the cerebral vascular dysfunction? What is the main finding and its importance? Electron paramagnetic resonance analysis shows that the oxidative stress induced after a single 1 h exposure to electronic cigarette aerosol takes ≤72 h to return to normal, which mirrors the time course for vascular dysfunction in the middle cerebral artery that we have reported previously.

Maternal mortality rates are at an all-time high across the world and are set to increase in subsequent years. Cardiovascular disease is the leading cause of death during pregnancy and postpartum, especially in the United States. Therefore, understanding the physiological changes in the cardiovascular system during normal pregnancy is necessary to understand disease-related pathology. Significant systemic and cardiovascular physiological changes occur during pregnancy that are essential for supporting the maternal-fetal dyad. The physiological impact of pregnancy on the cardiovascular system has been examined in both experimental animal models and in humans. However, there is a continued need in this field of study to provide increased rigor and reproducibility. Therefore, these guidelines aim to provide information regarding best practices and recommendations to accurately and rigorously measure cardiovascular physiology during normal and cardiovascular disease-complicated pregnancies in human and animal models.

Endothelial dysfunction is a predictor for cardiovascular disease. Preclinical data suggest longstanding cardiovascular and cerebrovascular dysfunction occurs in offspring with perinatal electronic cigarette (Ecig) exposure. Furthermore, direct use of Ecigs increases reactive oxygen species and impairs cerebrovascular function, but the combined effect of direct use in offspring with a history of perinatal exposure (i.e. double-hit condition) is not known. We tested the hypothesis that offspring with double-hit Ecig exposure will lead to greater cerebrovascular and neurocognitive dysfunction compared with in utero exposure only. Male and female offspring were obtained from time-mated Sprague Dawley female rats exposed to air (n = 5 dams) or Ecig exposed (n = 5 dams) and studied at either 3 or 6 mo after birth. Ecig exposure for double-hit offspring began at 1-mo before the timepoints and lasted 4 wk (5 days/wk with 90-min exposure/day). We found double-hit offspring (Ecig:Ecig = exposure dam:offspring) sustained further blunted middle cerebral artery (MCA) reactivity, increased severity of neuronal damage, and increased interactions of astrocytes and endothelial cells compared with offspring with maternal (Ecig:Air) or direct (Air:Ecig) exposure only. Circulating extracellular vesicles (EVs) were increased, whereas sirtuin 1 (SIRT1) was decreased, in all Ecig-exposed groups compared with controls (Air:Air), with Ecig:Ecig group showing the greatest respective change for each. Electron paramagnetic resonance (EPR) spectroscopy revealed oxidative stress was the highest in the plasma of Ecig:Ecig group (P < 0.05) than the other groups. These data show that a double-hit exposure in adolescent or adult offspring results in a greater decline in cerebrovascular function, biomarkers of neuronal dysfunction, and increased circulation of EVs compared with a single-hit exposure. NEW & NOTEWORTHY These data add to the growing body of literature demonstrating that electronic cigarette (Ecig) use during pregnancy (even without nicotine) is not safe, and primes offspring to have worse cardiovascular health outcomes in early and adult life. A key finding from this work is that a second insult from direct vaping in offspring with prior in utero exposure induces greater vascular dysfunction, increased oxidative stress, and shows evidence of neuronal dysfunction compared with either direct- or maternal-only exposure.

Studies have shown cerebrovascular dysfunction in offspring with full-gestational electronic cigarette (Ecig) exposure, but little is known about how individual trimester exposure impacts offspring health. This study aimed to determine if there is a critical window during gestation that contributes to vascular and anxiety-like behavioural changes seen with full-term exposure. To test this, rats were time-mated, and the pregnant dams were randomly assigned to Ecig exposure during first trimester (gestational day, GD2-7), second trimester (GD8-14), third trimester (GD15-21) or full-term gestation (GD2-21). We also assessed the effect of maternal preconception exposure. Both male and female offspring from all maternal exposure conditions were compared to offspring from dams under ambient air (control) conditions. Ecig exposure consisted of 60-puffs/day (5 days/week) using either 5 or 30 watts for each respective exposure group. We found that maternal exposure to Ecig in the second and third trimesters resulted in a decrease (23-38%) in vascular reactivity of the middle cerebral artery (MCA) reactivity in 3- and 6-month-old offspring compared to Air offspring. Further, the severity of impairment was comparable to the full-term exposure (31-46%). Offspring also displayed changes in body composition, body mass, anxiety-like behaviour and locomotor activity, indicating that Ecigs influence neurodevelopment and metabolism. Maternal preconception exposure showed no impact on offspring body mass, anxiety-like behaviour, or vascular function. Thus, the critical exposure window where Ecig affects vascular development in offspring occurs during mid- to late-gestation in pregnancy, and both 5 W and 30 W exposure produce significant vascular dysfunction compared to Air. KEY POINTS: Exposure to electronic cigarettes (Ecigs) is known to increase risk factors for cardiovascular disease in both animals and humans. Maternal Ecig use during pregnancy in rodents is found to impair the vascular health of adolescent and adult offspring, but the critical gestation window for Ecig-induced vascular impairment is not known. This study demonstrates Ecig exposure during mid- and late-gestation (i.e. second or third trimester) results in impaired endothelial cell-mediated dilatation (i.e. middle cerebral artery reactivity) and alters anxiety-like behaviour in offspring. Maternal exposure prior to conception did not impact offspring's vascular or anxiety-like behavioural outcomes. Rodent models have been a reliable and useful predictor of inhalation-induced harm to humans. These data indicate maternal use of Ecigs during pregnancy should not be considered safe, and begin to inform clinicians and women about potential long-term harm to their offspring.

Despite claims of safety or harm reduction for electronic cigarettes (E-cig) use (also known as vaping), emerging evidence indicates that E-cigs are not likely safe, or necessarily safer than traditional cigarettes, when considering the user's risk of developing vascular dysfunction/disease. E-cigs are different from regular cigarettes in that E-cig devices are highly customizable, and users can change the e-liquid composition (such as the base solution, flavors, and nicotine level). Since the effects of E-cigs on the microvascular responses in skeletal muscle are poorly understood, we used intravital microscopy with an acute (one-time 10 puff) exposure paradigm to evaluate the individual components of e-liquid on vascular tone and endothelial function in the arterioles of the gluteus maximus muscle of anesthetized C57Bl/6 mice. Consistent with the molecular responses seen with endothelial cells, we found that the peripheral vasoconstriction response was similar between mice exposed to E-cig aerosol or cigarette smoke (i.e., 3R4F reference cigarette); this response was not nicotine dependent, and endothelial cell-mediated vasodilation was not altered within this acute exposure paradigm. We also report that, regardless of the base solution component [i.e., vegetable glycerin (VG)-only or propylene glycol (PG)-only], the vasoconstriction responses were the same in mice with inhalation exposure to 3R4F cigarette smoke or E-cig aerosol. Key findings from this work reveal that some component other than nicotine, in inhaled smoke or aerosol, is responsible for triggering peripheral vasoconstriction in skeletal muscle, and that regardless of one's preference for an E-cig base solution composition (i.e., ratio of VG-to-PG), the acute physiological response to blood vessels appears to be the same. The data suggest that vaping is not likely to be 'safer' than smoking towards blood vessels and can be expected to produce and/or result in the same adverse vascular health outcomes associated with smoking cigarettes.

Electronic cigarettes (e-cigs) are customizable tobacco products that allow users to select e-liquid composition, flavors, and (in some devices) adjust wattage or heat used to generate e-cig aerosol. This study compared vascular outcomes in a conducting vessel (thoracic aorta) and a resistance artery (middle cerebral artery, MCA) in C57Bl/6 mice exposed to e-cig aerosol generated from either pure vegetable glycerin (VG) or pure propylene glycol (PG) over 60-min (Study 1), and separately the effect of using 5- vs. 30-watt settings with an exposure of 100-min (Study 2). In Study 1, aortic endothelial-dependent-dilation (EDD) was only impaired with PG- exposure (p < 0.05) compared with air. In the MCA, EDD response was impaired by ∼50% in both VG and PG groups compared with air (p < 0.05). In Study 2, the aortic EDD responses were not different for either 5- or 30-watt exposed groups compared with air controls; however, in the MCA, both 5- and 30-watt groups were impaired by 32% and 55%, respectively, compared with air controls (p < 0.05). These pre-clinical data provide evidence that chronic exposure to aerosol produced by either VG or PG, and regardless of the wattage used, leads to vascular dysfunction at multiple levels within the arterial system. For all exposures, we observed greater impairment of arterial reactivity in a resistance artery (i.e. MCA) compared with the aorta. These data could suggest the smaller arteries may be more sensitive or first to be affected, or that different mechanism(s) for impairment may be involved depending on arterial hierarchy.

We observe a significant alteration in arterial structure and function in adolescent and adult offspring due to developmental exposure to toxicants resulting from perinatal maternal vaping. Taken together with previous work that described lasting dysfunction in cerebral microvasculature in offspring, these data underscore the adverse consequences of maternal exposure to electronic cigarette aerosol in conduit and resistance vessels alike, irrespective of nicotine content.

Electronic cigarettes (E-cigs) have been strategically marketed as a safer alternative to smoking even during pregnancy. Previous literature suggests that direct exposure to E-cigs disrupts insulin sensitivity and mitochondrial function. Yet, there are few studies looking into maternal E-cig exposure and the metabolic function of offspring, especially separating out the role of nicotine. We hypothesize that maternal vaping would induce vascular and metabolic disruption in offspring leading to obesity in adulthood. Female rats (N=25) were time-mated, and randomly assigned to the following exposure groups, ambient air (control, N=5), Ecig with no nicotine at either 5 (w)att or 30w (Ecig0-5w, n=5; Ecig0-30w, n=5) or Ecig with 50mg of nicotine (Ecig50-5w, n=5; Ecig50-30w, n=5). Exposure was 60 puffs/day (1.5hr/day, 5 days/week) beginning on gestational day 2-4 using whole-body chambers. E-liquid composition 50:50 vegetable glycerin, propylene glycol with no flavoring. Postnatal day ((PD)21) offspring were weighed and body composition was measured using an EchoMRI. Total fat, lean, and water content were measured. As the animal's aged body mass was recorded at 1-, 3-, 6-, and 12-months. Body weight at PD21 was significantly decreased in female (-16%±4%) and male (-18%±4%) offspring with all Ecig0 groups (independent of wattage) (p<0.05). In fat, lean and water mass this statistically significant decrease held true for Ecig0 offspring compared to controls (p<0.05). Surprisingly, the Ecig50 offspring overall did not follow a similar trend. Only the female 30w offspring showed a significant decrease (-15%±10%) in body weight compared to controls (p<0.05). As the offspring aged, the Ecig0 groups caught up in weight to air controls by 1-month. At 6-months, female and male offspring in both Ecig0 and Ecig50 groups were larger (18-28%) than air controls (p<0.05). This continued to 12-months of age with Ecig0 at a greater (range of 19-21%) than controls. At 12-months we also observed significant cerebrovascular impairment in Ecig0 groups, where middle cerebral artery reactivity (using pressure myography) as reduced in both 5- and 30-watt groups (24±6% and 53±5% change compared to Air; respectively; ANOVA exposure, p<0.05). Metabolic and vascular data from Ecig50 at 12-months are not yet available. These data show maternal vaping during pregnancy results in smaller offspring at weaning for the Ecig without nicotine, but not Ecig with nicotine; but as offspring age (regardless of nicotine) they gain more weight compared to controls. The wattage level used during vaping did not change this outcome. Taken together these data suggest maternal vaping during pregnancy (regardless of nicotine or wattage level) can negatively influence vascular function and alter body composition and metabolism in offspring resulting in greater weight gain (i.e. obesity) in adult offspring compared to controls. AHA Collaborative Science Award This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Despite the perception that e-cigarettes are safer than conventional cigarettes, numerous findings demonstrated that e-cigarette aerosol (EC) exposure induced compromised immune functionality, vascular changes even after acute exposure, and lung injury. Notably, altered neutrophil functionality and platelet hemodynamics have been observed post-EC exposure. It was hypothesized that EC exposure initiates an inflammatory response resulting in altered neutrophil behavior and increased neutrophil-platelet interaction in the pulmonary microvasculature. Neutrophil and platelet responses were examined up to 48 hrs following whole-body, short-term EC exposure without flavorants or nicotine in a murine model, which most closely modeled secondhand exposure. This study is the first to investigate the impact of EC exposure through lung intravital imaging. Compared to room air-exposed mice, EC-exposed mice displayed significantly increased 1.7‒1.9-fold number of neutrophils in the pulmonary microvasculature associated with no marked change in neutrophils within whole blood or bronchoalveolar lavage fluid (BALF). Neutrophil-platelet interactions were also significantly elevated 1.9‒2.5-fold in exposed mice. Plasma concentration of myeloperoxidase was markedly reduced 1.5-fold 48 hr following exposure cessation, suggesting suppressed neutrophil antimicrobial activity. Cytokine expression exhibited changes indicating vascular damage. Effects persisted for 48 hr post-EC exposure. Data demonstrated that EC exposure repeated for 3 consecutive days in 2.5 hr intervals in the absence of flavorants or nicotine resulted in modified pulmonary vasculature hemodynamics, altered immune functionality, and a pro-inflammatory state in female BALB/cJ mice.

The hypoxic ventilatory response (HVR) is the increase in breathing in response to reduced arterial oxygen pressure. Over several decades, studies have revealed substantial population-level differences in the magnitude of the HVR as well as significant inter-individual variation. In particular, low HVRs occur frequently in Andean high-altitude native populations. However, our group conducted hundreds of HVR measures over several years and commonly observed low responses in sea-level populations as well. As a result, we aimed to determine the normal HVR distribution, whether low responses were common, and to what extent variation in study protocols influence these findings. We conducted a comprehensive search of the literature and examined the distributions of HVR values across 78 studies that utilized step-down/steady-state or progressive hypoxia methods in untreated, healthy human subjects. Several studies included multiple datasets across different populations or experimental conditions. In the final analysis, 72 datasets reported mean HVR values and 60 datasets provided raw HVR datasets. Of the 60 datasets reporting raw HVR values, 35 (58.3%) were at least moderately positively skewed (skew > 0.5), and 21 (35%) were significantly positively skewed (skew > 1), indicating that lower HVR values are common. The skewness of HVR distributions does not appear to be an artifact of methodology or the unit with which the HVR is reported. Further analysis demonstrated that the use of step-down hypoxia versus progressive hypoxia methods did not have a significant impact on average HVR values, but that isocapnic protocols produced higher HVRs than poikilocapnic protocols. This work provides a reference for expected HVR values and illustrates substantial inter-individual variation in this key reflex. Finally, the prevalence of low HVRs in the general population provides insight into our understanding of blunted HVRs in high-altitude adapted groups.