Exposure to cigarette smoke disturbs adipokines secretion causing intercellular damage and insulin resistance in high fructose diet-induced metabolic disorder mice

Inhaled exposure to air fresheners aggravated liver injury in a murine model of nonalcoholic fatty acid liver disease

At present, the consumption and use of air fresheners (AFs) is rapidly increasing worldwide for the purposes of odor removal and to create a pleasant odor. Many recent studies have strongly suggested that the potentially hazardous chemicals emitted from AFs may be the primary source of indoor air pollutants and may cause adverse health effects. Despite the presence of hazardous chemicals in AFs, potential adverse health effects and risk assessment of AFs have not yet been established. The incidence of nonalcoholic fatty acid liver disease (NAFLD) around the world is rapidly increasing, as with obesity and diabetes, and is one of the most common causes of liver disease worldwide. Based on the demonstrated evidence that NAFLD could eventually develop into further health complications such as liver failure, cardiovascular disease, liver cirrhosis, or liver cancer, the current study was performed to clarify the relationship between inhaled AF exposure and NAFLD using a high-fructose diet (HFr)-induced murine model. The results from current study clearly demonstrated that AF exposure further exacerbated liver injury in NAFLD-induced mice. Interestingly, the increased expression of fibrosis-related factors and collagen accumulation in the liver of AF-exposed NAFLD-induced mice resulted in nonalcoholic steatohepatitis (NASH)-like phenotype and fibrosis. Taken together, these results strongly suggest that AF exposure may not only induce liver injury but may also exacerbate NAFLD to lead to NASH-like symptoms. Further study is needed to shed light on the detailed mechanisms behind AF-induced liver effects and its potential role in exacerbating NAFLD to more detrimental disease in order to better scientific evidence for risk assessments of indoor AF exposure.

Association between environmental tobacco smoke exposure and risk of type 2 diabetes mellitus in Chinese female never smokers: A population-based cohort study

BACKGROUND

Evidence for the association between environmental tobacco smoke (ETS) exposure and the risk of type 2 diabetes mellitus (T2DM) is limited. The aim of this study was to investigate this association in female never smokers.

METHODS

We analyzed 28 177 female participants of the China Kadoorie Biobank (CKB) in the Suzhou area, who were never smokers and had no diabetes. ETS exposure was defined as being exposed to other people's tobacco smoke either at home, workplace, or in public places at least 1 d/wk. Cox proportional hazard regression models were used to assess the association between ETS exposure and incident T2DM according to the frequency and duration of ETS exposure.

RESULTS

A total of 774 incident cases of T2DM were identified during a median 7.3-year follow-up. Compared with no ETS exposure, hazard ratios (95% CIs) for all ETS exposure, daily, and ≥14 h/wk ETS exposure were 1.17 (1.00-1.37), 1.23 (1.04-1.46), and 1.25 (1.03-1.53), respectively. Moreover, a positive dose-response relationship was observed between ETS exposure level and T2DM (all P <.05 for trend).

CONCLUSIONS

This prospective study suggests that ETS exposure increases the risk of T2DM incidence with dose-response relationship in female never smokers. Thus, reducing ETS exposure may help decrease the burden of T2DM in Chinese females.

Effect of present versus previous smoking on non-invasive haemodynamics

We examined cardiovascular function in 637 volunteers (19-72 years) without antihypertensive medication in never smokers (n = 365), present smokers (n = 81) and previous smokers (n = 191, median abstinence 10 years). Haemodynamics during passive head-up tilt were recorded using whole-body impedance cardiography and radial pulse wave analysis. Results were adjusted for age, sex, body mass index, LDL cholesterol and alcohol use. Systolic and diastolic blood pressure, heart rate, and pulse wave velocity were not different between the groups. Supine aortic reflection times did not differ, while upright values were shorter in present versus previous smokers (p = 0.04). Heart rate adjusted augmentation index was increased in the supine position in present smokers versus controls (p = 0.045), and in present (p < 0.001) and previous (p = 0.031) smokers versus controls in the upright position. Supine and upright cardiac output was higher (p ≤ 0.016) and systemic vascular resistance lower (p ≤ 0.001) in present versus previous smokers. In spite of the long abstinence, in the upright position previous smokers had lower cardiac output (p = 0.032) and higher systemic vascular resistance (p = 0.014) than never smokers. In the absence of differences in blood pressure and arterial stiffness, present smokers presented with hyperdynamic circulation and enhanced wave reflection compared with previous smokers.

In type 2 diabetes induced by cigarette smoking, activation of p38 MAPK is involved in pancreatic β-cell apoptosis

Type 2 diabetes (T2D) is a chronic disease caused by pancreatic β-cell dysfunction and insulin resistance. Exposure to smoke is a risk factor for diabetes; however, its mechanisms are unclear. In an epidemiological study, we determined the relationship between cigarette smoking and β-cell function. T2D patients had a history of heavier smoking than people without T2D, and heavy smokers had more abnormal glucose metabolism. For various smoking populations, there was a dose-effect relationship between decreases of homeostatic model assessment (HOMA)-β levels or the increases of HOMA-insulin resistance (IR) levels and amount of smoking (pack-years), which indicated that smoking induced β-cell dysfunction. For MIN6 cells, cigarette smoke extract (CSE) decreased insulin secretion and content; enhanced apoptosis, as illustrated by decreases of BCL-2 levels, increases of BAX and cleaved caspase-3 levels, and an increased apoptotic index; and activated the p38 MAPK pathway. For MIN6 cells, inhibition of p-p38 MAPK by SB203580 prevented enhanced apoptosis and the dysfunction of insulin secretion induced by CSE. In sum, activation of p38 MAPK is involved in the apoptosis of pancreatic β-cells induced by cigarette smoking, which is a possible mechanism for induction of T2D by cigarette smoke.