Brain Structure Alterations in Respect to Tobacco Consumption and Nicotine Dependence: A Comparative Voxel-Based Morphometry Study.

The main purpose of this study is to examine the lifetime tobacco consumption and the degree of nicotine dependence related gray matter (GM) and white matter (WM) volume alterations in young adult-male smokers. Fifty-three long-term male smokers and 53 well-matched male healthy non-smokers participated in the study, and the smokers were respectively categorized into light and heavy tobacco consumption subgroups by pack-years and into moderate and severe nicotine dependence subgroups using the Fagerström Test for Nicotine Dependence (FTND). Voxel-based morphometry analysis was then performed, and ANCOVA analysis combined with subsequent post hoc test were used to explore the between-group brain volume abnormalities related to the smoking amount and nicotine dependence. Light and heavy smokers displayed smaller GM and WM volumes than non-smokers, while heavy smokers were found with more significant brain atrophy than light smokers in GM areas of precuneus, inferior and middle frontal gyrus, superior temporal gyrus, cerebellum anterior lobe and insula, and in WM areas of cerebellum anterior lobe. However, the contrary trend was observed regarding alterations associated with severity of nicotine dependence. Severe nicotine dependence smokers rather demonstrated less atrophy levels compared to moderate nicotine dependence smokers, especially in GM areas of precuneus, superior and middle temporal gyrus, middle occipital gyrus, posterior cingulate and insula, and in WM areas of precuneus, posterior cingulate, cerebellum anterior lobe and midbrain. The results reveal that the nicotine dependence displays a dissimilar effect on the brain volume in comparison to the cigarette consumption. Our study could provide new evidences to understand the adverse effects of smoking on the brain structure, which is helpful for further treatment of smokers.

Proteomic analysis for detecting serum biomarkers related to smoking in humans.

BACKGROUND: Smoking is the leading cause of death in the world. This study focused on the difference of the serum proteomic profiling between healthy smokers and nonsmokers in order to find smoking-specific serum biomarkers. METHODS: Pattern-based proteomic profiling of 100 serum samples (from 50 Chinese male smokers and 50 matched nonsmokers) was performed through magnetic bead fractionation coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis (MALDI-TOF-MS) and resulting data were statistically analyzed by Ciphergen ProteinChip software 3.0.2. RESULTS: We found 72 serum peaks were significantly different between smokers and nonsmokers (P < 0.05). Marker peaks of mass-to-charge ratio (m/z) 3159.13, 7561.03 and 9407.32 were smoking-specific. CONCLUSION: The preliminary data suggested that smoking-specific serum biomarkers could be detected in humans.

Association between 5-hydroxytryptamine transporter gene-linked polymorphic region and smoking behavior in Chinese males.

BACKGROUND: Tobacco use is the major risk factor for numerous health problems. However, only 5% of smokers can successfully quit without therapy owing to the highly addictive properties of nicotine. The serotoninergic system may be involved in smoking behavior because nicotine increases brain serotonin secretion, nicotine withdrawal decreases serotonin levels, and a selective serotonin reuptake inhibitor antagonizes the response to nicotine withdrawal. Serotonin transporter (5-HTT) is the most important protein, as it adjusts the serotonin concentration in the synaptic cleft. There is a polymorphism in the upstream regulatory region of the 5-HTT gene, named 5-hydroxytryptamine transporter gene-linked polymorphic region (5-HTTLPR). Compared with the L allele, the S allele of the polymorphism is associated with decreased transcription efficiency of the 5-HTT gene. In this study, we investigated the relationship between this gene polymorphism and smoking behavior in Chinese males. METHODS: Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to find 5-HTTLPR gene polymorphisms in 144 smokers and 135 age-matched healthy non-smokers. A questionnaire was completed in all recruited subjects. RESULTS: The proportion of L/L (15.3% vs 5.2%) and S/L (50.0% vs 33.3%) genotypes was significantly higher in the smokers than that in the non-smokers (chi(2) = 21.9; P < 0.01). The odds ratio (OR) adjusted by age, education, effects of family members and friends who smoke, and alcohol intake was 2.9 (95% CI 1.78 +/- 4.80). In smokers, the number of cigarettes/day (L/L vs S/L vs S/S: 28 +/- 12 vs 20 +/- 8 vs 16 +/- 6, chi(2) = 18.5, P < 0.01), smoking index (L/L vs S/L vs S/S: 561 +/- 446 vs 393 +/- 341 vs 237 +/- 201, chi(2) = 12.5, P < 0.01) and score on the Fagerström test for nicotine dependence (FTND) (L/L vs S/L vs S/S: 7.8 +/- 1.6 vs 6.2 +/- 2.5 vs 3.5 +/- 2.1, chi(2) = 48.3, P < 0.01) were significantly higher in smokers with an L/L or S/L genotype than that in the smokers with the S/S genotype. There were no significant differences in the proportion of starting smoking before 20 years old (P = 0.219) and those who succeeded in quitting smoking for more than 1 month (P = 0.456) between individuals with different 5-HTTLPR genotypes in smokers. CONCLUSIONS: 5-HTTLPR polymorphism may be associated with susceptibility to cigarette smoking in Chinese males. The proportion of the L/L and S/L genotype in smokers was higher than that in non-smokers. In smokers, the level of nicotine dependence and resultant cigarettes consumption may be much higher in individuals with an L/L or S/L genotype than those with the S/S genotype.