Effects of cigarette smoking and alcohol use on neurocognition and BDNF levels in a Chinese population

Alterations in Neurotrophins in Alcohol-Addicted Patients during Alcohol Withdrawal

BACKGROUND

Alcohol use disorder (AUD) is related to mental and somatic disorders that result in alcohol withdrawal syndrome (AWS), with 30% of AWS cases leading to life-threatening delirium tremens (DTs). Currently, studies do not support using any one biomarker in DTs. Neurotrophins affect neuromodulation, playing a role in the pathogenesis of AUD, AWS, and DTs.

METHODS

This review aims to summarize experimental and clinical data related to neurotrophins and S100B in neuroplasticity, as well as neurodegeneration in the context of AUD, AWS, and DTs. This work used publications that were selected based on the protocol consistent with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement.

RESULTS

The BDNF level could be a good candidate biomarker for relapse susceptibility, as it is significantly reduced during consumption and gradually increases during abstinence. GDNF influences AUD through its integral role in the function of dopaminergic neurons and ablates the return to alcohol-drinking behavior. NGF protects neurons from ethanol-induced cytotoxic damage and affects recovery from cognitive deficits after brain damage. The NT-3 level is decreased after alcohol exposure and is involved in compensatory mechanisms for cognitive decline in AUD. NT-4 affects oxidative stress, which is associated with chronic alcohol consumption. S100B is used as a biomarker of brain damage, with elevated levels in serum in AUD, and can protect 5-HT neurons from the damage caused by alcohol.

CONCLUSIONS

BDNF, GDNF, NT-3, NT-4, NGF, and S100B may be valuable markers for withdrawal syndrome. In particular, the most relevant is their association with the development of delirium complications. However, there are few data concerning some neurotrophins in AWS and DTs, suggesting the need for further research.

Association between the HHEX polymorphism and delayed memory in first-episode schizophrenic patients

The hematopoietically-expressed homeobox gene (HHEX) played a critical role in regulating the immune system that the abnormality of which was involved in the psychopathology and cognitive deficits of psychiatric disorders. The aim of this study was to investigate the effect of HHEX rs1111875 polymorphism on the susceptibility and cognitive deficits of first-episode schizophrenic patients (FSP). We assessed cognitive function in 239 first-episode patients meeting DSM-IV for schizophrenia, and 368 healthy controls using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The HHEX rs1111875 polymorphism was genotyped. Our results showed that the allelic and genotypic frequencies of HHEX rs1111875 polymorphism didn't differ between FSP and healthy controls (both p > 0.05) after adjusting for sex and age. Cognitive test scores in FSP were significantly lower than those in healthy controls on all scales (all p < 0.001) except for the visuospatial/constructional score (p > 0.05) after adjusting for covariates. There was a significant genotype (p < 0.05) rather than genotype × diagnosis (p > 0.05) effect on the delayed memory score after adjusting for covariates. The HHEX rs1111875 polymorphism was significantly associated with the delayed memory score in FSP (p < 0.05), but not in healthy controls (p > 0.05) after adjusting for covariates. Our findings supported that the HHEX rs1111875 polymorphism did not contribute to the susceptibility to FSP. However, this polymorphism might influence the delayed memory in FSP. Moreover, FSP had poorer cognitive function than healthy controls except for the visuospatial/constructional domain.

Effect of smoking on Brain-Derived Neurotrophic Factor (BDNF) blood levels: A systematic review and meta-analysis

BACKGROUND

Brain-Derived Neurotrophic Factor (BDNF) is a neurotrophin that plays a crucial role in neuronal survival and plasticity. Previous studies have suggested that smoking may influence BDNF levels, but the findings have been inconsistent.

METHODS

A comprehensive search of electronic databases was conducted to identify relevant studies. Inclusion criteria were applied to select studies that investigated the relationship between smoking and blood levels of BDNF. A random-effects model was used to estimate the overall effect size.

RESULTS

A total of 23 studies were included. The meta-analysis revealed a significant association between smoking and increased blood levels of BDNF (standardized mean difference [SMD] = -0.38, 95 % confidence interval [CI] 0.15 to 0.62, p = 0.002). Subgroup analyses based on BDNF source showed a significant increase in plasma-derived BDNF levels (SMD = 1.02, 95 % CI 0.50 to 1.53, p = 0.0001), while no significant difference was observed in serum-derived BDNF levels (SMD = 0.02, 95 % CI -0.19 to 0.22, p = 0.87). The pooled analysis revealed a non-significant difference in blood levels of BDNF between former smokers and non-smokers (random-effects model, SMD = 0.21, 95 % CI -0.04 to 0.46, p = 0.1).

CONCLUSION

Smokers exhibited significantly higher plasma levels of BDNF compared to non-smokers. Further research is needed to elucidate the underlying mechanisms and explore the potential therapeutic implications of targeting BDNF in smoking.

Effect of Glycemic Disorders and Habits on the Concentration of Selected Neurotrophic Factors in Patients with Lumbosacral Intervertebral Disc Degeneration

BACKGROUND

Unhealthy habits, such as overeating processed and high-calorie foods, alcohol abuse, and smoking, negatively impact human health. It has been suggested that the inflammatory process and the resulting growth of nerve fibers within the intervertebral disc (IVD) fissures is the main reason for the pain accompanying IVD degeneration (IVDD).

OBJECTIVES

The aim of this study was to determine whether smoking, alcohol consumption, overweight/obesity, or diabetes comorbidity contribute to the development of IVDD and how the aforementioned factors affect the levels of brain-derived neurotrophic factor (BDNF), glial cell-derived neurotrophic factor (GDNF), and growth associated protein 43 (GAP-43) in the study and control groups (intervertebral discs, IVDs from cadavers, and serum samples from voluntary blood donors).

METHODS

The study group comprised 113 patients diagnosed with IVDD who qualified for microdiscectomy. Two control groups (I and II) were used in this study. The first included 81 IVDs obtained from Caucasian human cadavers. Control group II, on the other hand, included serum samples obtained from 113 voluntary blood donors. The expression profiles of BDNF, GDNF, and GAP-43 were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Our statistical analysis confirmed that patients who were overweight/obese, smoked tobacco, consumed alcohol, or had diabetes had a higher risk of IVDD (OR > 1). Statistical analysis showed that BDNF, GAP-43, and GDNF concentrations were significantly higher in the IVDs and serum samples obtained from the study group compared to the control group (p < 0.05). In addition, higher levels of BDNF, GDNF, and GAP-43 were noted in IVDD patients who consumed alcohol, smoked tobacco, were overweight/obese, or had comorbid diabetes compared to patients without these risk factors (p < 0.05).

CONCLUSION

We showed that changes in energy metabolism, habits, and lifestyle, as well as the degenerative process of IVD in the lumbosacral spine contribute to changing the concentration profile of the analyzed neurotrophic factors.

Correlation between long-term glycemic variability and cognitive function in middle-aged and elderly patients with type 2 diabetes mellitus: a retrospective study

Objective

To investigate the correlation between long-term glycemic variability and cognitive function in middle-aged and elderly patients with type 2 diabetes mellitus (T2DM).

Methods

This retrospective analysis includes 222 patients hospitalized at Second Affiliated Hospital of Anhui Medical University from June 2021 to June 2023. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE). All patients were categorized into the MCI group and the non-MCI group based on their MoCA score. Long-term blood glucose fluctuations were measured using glycated hemoglobin A1c standard deviation (HbA1c-SD) and fasting plasma glucose standard deviation (FPG-SD). The study compared general clinical data, blood biochemical indicators, and glycemic variability indicators between the two groups. The differences between the groups were compared using t-test, Chi-Square Test, or Mann-Whitney U test. Kendall's correlation analysis, multivariate logistic regression analysis and ROC curve correlation analysis were further used to analyze the correlation and diagnostic power.

Results

The differences in age, MoCA scores, MMSE scores, HOMA-β, HbA1c-M, HbA1c-SD, FPG-M, FPG-SD, eGFR, Smoking, GLP-1RA and SGLT-2i usage were statistically significant between the two groups (P < 0.05). Kendall's correlation analysis showed that age, HbA1c-M, HbA1c-SD, FPG-M, and FPG-SD was negatively correlated with MoCA scores; meanwhile, the HOMA-β, and eGFR was positively correlated with MoCA scores. Multiple logistic regression analysis revealed that HbA1c-SD, FPG-SD and Smoking were risk factors for cognitive dysfunction, while eGFR, GLP-1RA and SGLT-2i usage was a protective effect. The area under the curve (AUC) values for predicting MCI prevalence were 0.830 (95% CI [0.774-0.877], P < 0.001) for HbA1c-SD, 0.791 (95% CI [0.655-0.808], P < 0.001) for FPG-SD, and 0.698 (95% CI [0.633-0.757], P < 0.001) for eGFR. The optimal diagnostic values were 0.91, 1.32, and 74.81 ml/min/1.73 m2 for HbA1c-SD, FPG-SD, and eGFR, respectively.

Conclusions

Cognitive function in middle-aged and elderly T2DM patients is influenced by long-term blood glucose variability, with poorer cognitive function observed in individuals with higher blood glucose variability. The impact of HbA1c-SD on MCI exhibited a greater magnitude compared to that of PFG-SD and smoking. Additionally, renal function, GLP-1RA and SGLT-2i usage exert positive effects on cognitive function.

Effect of alcohol on Brain-Derived Neurotrophic Factor (BDNF) blood levels: a systematic review and meta-analysis

Brain-Derived Neurotrophic Factor (BDNF) is a vital protein involved in neuronal development, survival, and plasticity. Alcohol consumption has been implicated in various neurocognitive deficits and neurodegenerative disorders. However, the impact of alcohol on BDNF blood levels remains unclear. This systematic review and meta-analysis aimed to investigate the effect of alcohol consumption on BDNF blood levels. A comprehensive search of electronic databases was conducted to identify relevant studies. Eligible studies were selected based on predefined inclusion criteria. Data extraction was performed, and methodological quality was assessed using appropriate tools. A meta-analysis was conducted to estimate the overall effect size of alcohol consumption on BDNF levels. A total of 25 studies met the inclusion criteria and were included in the final analysis. Alcohol use and BDNF blood levels were significantly correlated, according to the meta-analysis (p = 0.008). Overall, it was discovered that drinking alcohol significantly decreased BDNF levels (SMD: - 0.39; 95% CI: - 0.68 to - 0.10; I2: 93%). There was a non-significant trend suggesting that alcohol withdrawal might increase BDNF levels, with an SMD of 0.26 (95% CI: - 0.09 to 0.62; I2: 86%; p = 0.14). Subgroup analysis based on the source of BDNF demonstrated significant differences between the subgroups (p = 0.0008). No significant publication bias was observed. This study showed that alcohol consumption is associated with a significant decrease in BDNF blood levels. The findings suggest a negative impact of alcohol on BDNF levels regardless of alcohol dosage. Further studies are needed to strengthen the evidence and elucidate the underlying mechanisms.

Association between uric acid and cognitive dysfunction: A cross-sectional study with newly diagnosed, drug-naïve with bipolar disorder

BACKGROUND

Cognitive impairment is one of the major symptoms of individuals with bipolar disorder (BD). Purine system disorders may play an important role in cognitive dysfunction. So far, the relationship between cognitive deficits and purinergic metabolism in BD has been seldom discussed in previous studies. This study aims to explore its relevance and potential biological mechanisms.

METHODS

In this cross-sectional study, 205 first time diagnosed drug-naive individuals with BD and 97 healthy volunteers were recruited. The uric acid(UA) level was measured using automatic biochemical analyzer, and cognitive function was assessed by Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Stroop color-word test. In addition, general information and clinical symptoms were collected and evaluated.

RESULTS

In this study, the UA level of BD group (U = 8475.000, p = 0.038) was found to be significantly higher than that of the healthy controls, but the scores of RBANS (t = -11.302, p < 0.001) and Stroop color-word test (t = -6.962, p < 0.001) were significantly lower than that of the healthy controls. In gender subgroup analysis, females had lower UA level and higher RBANS scores. In correlation analysis, the cognitive function of individuals with BD was found to present a significant negative correlation with UA level in attention (r = -0.23, p = 0.001) and delayed memory(r = -0.16, p = 0.022).

LIMITATIONS

This is a cross-sectional design.

CONCLUSION

Elevated UA levels may be a potential mechanism of cognitive impairment in BD. This provides a new possible strategy for the prevention and treatment of cognitive impairment in BD.

Role of BDNF in Neuroplasticity Associated with Alcohol Dependence

Abstract

Chronic alcohol consumption is characterized by disturbances of neuroplasticity. Brain-derived neurotrophic factor (BDNF) is believed to be critically involved in this process. Here we aimed to review actual experimental and clinical data related to BDNF participation in neuroplasticity in the context of alcohol dependence. As has been shown in experiments with rodents, alcohol consumption is accompanied by the brain region-specific changes of BDNF expression and by structural and behavioral impairments. BDNF reverses aberrant neuroplasticity observed during alcohol intoxication. According to the clinical data parameters associated with BDNF demonstrate close correlation with neuroplastic changes accompanying alcohol dependence. In particular, the rs6265 polymorphism within the BDNF gene is associated with macrostructural changes in the brain, while peripheral BDNF concentration may be associated with anxiety, depression, and cognitive impairment. Thus, BDNF is involved in the mechanisms of alcohol-induced changes of neuroplasticity, and polymorphisms within the BDNF gene and peripheral BDNF concentration may serve as biomarkers, diagnostic or prognostic factors in treatment of alcohol abuse.

Smoking affects the association between cognitive impairment and P50 inhibition defects in patients with chronic schizophrenia: A case-control study

OBJECTIVE

Smoking affects sensory gating, as assessed by the event related potential P50, which is evoked by auditory stimuli and is considered to be involved in the pathophysiology of schizophrenia (SCZ). However, few studies have compared sensory gating and cognitive performance between smoking and non-smoking SCZ patients in the Chinese Han population.

METHODS

We recruited two groups of Chinese subjects: 128 male chronic SCZ patients and 76 male healthy controls, measuring cognition with the MATRICS Consensus Cognitive Battery (MCCB) and sensory gating with the P50 EEG components. Based on their smoking status, they were further divided into 4 subgroups: smoking SCZ patients, non-smoking SCZ patients, smoking healthy controls, and non-smoking healthy controls. We assessed psychopathological symptoms of the patients using the Positive and Negative Syndrome Scale (PANSS).

RESULTS

Compared with healthy controls, SCZ patients had lower MCCB total score and scores of all 10 tests (all p < 0.05), while SCZ patients had higher S2 amplitudes and P50 ratios (both p < 0.05). When comparing smoking versus non-smoking SCZ patients, non-smokers had significantly better spatial span (p < 0.05). Furthermore, the S1 amplitude was negatively correlated with the Brief Visuospatial Memory Test (BVMT-R) in smoking patients (p < 0.05), while the S1 latency was negatively correlated with spatial span in non-smoking patients (p < 0.01).

CONCLUSIONS

Our finding shows a difference in the relationship between sensory gated P50 and cognition in smoking and non-smoking SCZ patients, suggesting that nicotine may improve cognitive and P50 deficits in SCZ patients.

Research progress on risk factors of delirium in burn patients: A narrative review

Delirium, an acute brain dysfunction, is a common and serious complication in burn patients. The occurrence of delirium increases the difficulty of patient treatment, is associated with various adverse outcomes, and increases the burden on the patient's family. Many scholars have studied the factors that cause delirium, but the causes, pathogenesis, and treatment of delirium in burn patients have not been fully revealed. There is no effective pharmacological treatment for delirium, but active preventive measures can effectively reduce the incidence of delirium in burn patients. Therefore, it is necessary to study the relevant factors affecting the occurrence of delirium in burn patients. This study was conducted on December 20, 2021 by searching the PubMed database for a narrative review of published studies. The search strategy included keywords related to "burns," "delirium," and "risk factors." We reviewed the characteristics of delirium occurrence in burn patients and various delirium assessment tools, and summarized the risk factors for the development of delirium in burn patients in terms of personal, clinical, and environmental factors, and we found that although many risk factors act on the development of delirium in burn patients, some of them, such as clinical and environmental factors, are modifiable, suggesting that we can estimate the exposure of burn patients to risk factors by assessing their likelihood of delirium occurring and to make targeted interventions that provide a theoretical basis for the prevention and treatment of burn delirium.

Administration of brain-derived neurotrophic factor in the ventral tegmental area produces a switch from a nicotine nondependent D1R-mediated motivational state to a nicotine dependent-like D2R-mediated motivational state

Brain-derived neurotrophic factor (BDNF) has been implicated in the transition from a nondependent motivational state to a drug-dependent and -withdrawn motivational state. Chronic nicotine can increase BDNF in the rodent brain and is associated with smoking severity in humans; however, it is unknown whether this increased BDNF is linked functionally to the switch from a nicotine-nondependent to a nicotine-dependent state. We used a place conditioning paradigm to measure the conditioned responses to nicotine, showing that a dose of acute nicotine that nondependent male mice find aversive is found rewarding in chronic nicotine-treated mice experiencing withdrawal. A single BDNF injection in the ventral tegmental area (in the absence of chronic nicotine treatment) caused mice to behave as if they were nicotine-dependent and in withdrawal, switching the neurobiological substrate mediating the conditioned motivational effects from dopamine D1 receptors to D2 receptors. Quantification of gene expression of BDNF and its receptor, tropomyosin-receptor-kinase B (TrkB), revealed an increase in TrkB mRNA but not BDNF mRNA in the VTA in nicotine-dependent and -withdrawn mice. These results suggest that BDNF signaling in the VTA is a critical neurobiological substrate for the transition to nicotine dependence. The modulation of BDNF signaling may be a promising new pharmacological avenue for the treatment of addictive behavior.

Effects of Cigarette Smoking on Resting-State Functional Connectivity of the Nucleus Basalis of Meynert in Mild Cognitive Impairment

Background: Mild cognitive impairment (MCI) is the prodromal phase of Alzheimer’s disease (AD) and has a high risk of progression to AD. Cigarette smoking is one of the important modifiable risk factors in AD progression. Cholinergic dysfunction, especially the nucleus basalis of Meynert (NBM), is the converging target connecting smoking and AD. However, how cigarette smoking affects NBM connectivity in MCI remains unclear.

Objective: This study aimed to evaluate the interaction effects of condition (non-smoking vs. smoking) and diagnosis [cognitively normal (CN) vs. MCI] based on the resting-state functional connectivity (rsFC) of the NBM.

Methods: After propensity score matching, we included 86 non-smoking CN, 44 smoking CN, 62 non-smoking MCI, and 32 smoking MCI. All subjects underwent structural and functional magnetic resonance imaging scans and neuropsychological tests. The seed-based rsFC of the NBM with the whole-brain voxel was calculated. Furthermore, the mixed effect analysis was performed to explore the interaction effects between condition and diagnosis on rsFC of the NBM.

Results: The interaction effects of condition × diagnosis on rsFC of the NBM were observed in the bilateral prefrontal cortex (PFC), bilateral supplementary motor area (SMA), and right precuneus/middle occipital gyrus (MOG). Specifically, the smoking CN showed decreased rsFC between left NBM and PFC and increased rsFC between left NBM and SMA compared with non-smoking CN and smoking MCI. The smoking MCI showed reduced rsFC between right NBM and precuneus/MOG compared with non-smoking MCI. Additionally, rsFC between the NBM and SMA showed a significant negative correlation with Wechsler Memory Scale-Logical Memory (WMS-LM) immediate recall in smoking CN (r = −0.321, p = 0.041).

Conclusion: Our findings indicate that chronic nicotine exposure through smoking may lead to functional connectivity disruption between the NBM and precuneus in MCI patients. The distinct alteration patterns on NBM connectivity in CN smokers and MCI smokers suggest that cigarette smoking has different influences on normal and impaired cognition.

Ceftriaxone Reduces Waterpipe Tobacco Smoke Withdrawal-induced Anxiety in rats via Modulating the Expression of TNF-α/NFĸB, Nrf2, and GLT-1

Tobacco exposure has been linked to neuroinflammation and adaptive/maladaptive changes in neurotransmitter systems, including in glutamatergic systems. We examined the effects of waterpipe tobacco smoke (WTS) on inflammatory mediators and astroglial glutamate transporters in mesocorticolimbic brain regions including the prefrontal cortex (PFC), nucleus accumbens (NAc) and ventral tegmental area (VTA). The behavioral consequences of WTS exposure on withdrawal-induced anxiety-like behavior were assessed using elevated plus maze (EPM) and open field (OF) tests. Male Sprague-Dawley rats were randomly assigned to 3 experimental groups: a control group exposed only to standard room air, a WTS exposed group treated with saline vehicle, and a WTS exposed group treated with ceftriaxone. WTS exposure was performed for 2 h/day, 5 days/week, for 4 weeks. Behavioral tests (EPM and OF) were conducted weekly 24 h after WTS exposure, during acute withdrawal. During week 4, rats were given either saline or ceftriaxone (200 mg/kg i.p.) 30 min before WTS exposure. WTS increased withdrawal-induced anxiety, and ceftriaxone attenuated this effect. WTS exposure increased the relative mRNA levels for nuclear factor ĸB (NFĸB), tumor necrosis factor-α (TNF-α), and brain-derived neurotrophic factor (BDNF) in the PFC, NAc and VTA, and ceftriaxone treatment reversed these effects. In addition, WTS decreased the relative mRNA of nuclear factor erythroid 2 related factor 2 (Nrf2), glutamate transporter 1 (GLT-1) and cystine-glutamate transporter (xCT) in PFC, NAc and VTA, and ceftriaxone treatment normalized their expression. WTS caused neuroinflammation, alteration in relative mRNA glutamate transport expression, and increased anxiety-like behavior, and these effects were attenuated by ceftriaxone treatment.

The effect of smoking on cognition as measured by Cambridge Neuropsychological Test Automated Battery (CATNAB) and brain-derived neurotrophic factor plasma levels

OBJECTIVES

 To establish an association between cigarette smoking, cognition, and plasma brain-derived neurotrophic factor (BDNF) levels in healthy young adults.

METHODS

 This was an ex post facto analytic cross-sectional study conducted between March and November 2018. Participants were 73 healthy males (31 smokers and 42 non-smokers), 17-33 years old. The cognitive function of the participants was assessed through the Cambridge neuropsychological test automated battery (CANTAB). Blood samples were taken to measure the plasma levels of BDNF and the results were compared to identify the association between smoking related variables and cognitive test scores and plasma BDNF levels. A p-value of less than 0.05 was considered statistically significant.

RESULTS

 Smokers performed significantly worse than non-smokers in the multitasking test, including reaction time and rapid visual information processing. However, no significant association was observed between smoking related variables and cognitive test scores. The only significant positive correlation was found between plasma BDNF levels and the number of cigarettes smoked per day (r=0.480, p=0.024). No correlation was observed between other smoking related variables and plasma BDNF levels.

CONCLUSION

 Plasma BDNF level is positively related to the number of cigarettes smoked per day. Young smokers have significantly impaired sustained attention and less ability to manage conflicting information as compared to age-matched non-smokers.

Evolution of BDNF serum levels during the first six months after alcohol withdrawal

OBJECTIVES

Brain-Derived Neurotrophic Factor (BDNF) has been associated with alcohol dependence and appear to vary after withdrawal, although the link with the withdrawal outcome on the long term is unknown. We aimed to assess the evolution of BDNF levels during the six months following withdrawal and determine the association with the status of alcohol consumption.

METHODS

Serum BDNF levels of alcohol-dependent patients (n = 248) and biological and clinical parameters were determined at the time of alcohol cessation (D0), 14 days (D14), 28 days (D28), and 2, 4, and 6 months after (M2, M4, M6).

RESULTS

Abstinence decreased during follow-up and was 31.9% after six months. BDNF levels increased by 14 days after withdrawal and remained elevated throughout the six-month period, independently of alcohol consumption. Serum BDNF levels evolved over time (p < 0.0001), with a correlation between BDNF and GGT levels. The prescription of baclofen at the time of withdrawal was associated with higher serum BDNF levels throughout the follow-up and that of anti-inflammatory drugs with lower BDNF levels.

CONCLUSIONS

A link between BDNF levels, liver function, and the inflammatory state in the context of alcohol abuse and not only with alcohol dependence itself is proposed.

One-day tropisetron treatment improves cognitive deficits and P50 inhibition deficits in schizophrenia

The core features of schizophrenia (SCZ) include cognitive deficits and impaired sensory gating represented by P50 inhibition deficits, which appear to be related to the α7 nicotinic acetylcholine receptor (nAChR). An agonist of nAChR receptor may improve these defects. This study aimed to investigate how administering multiple doses of tropisetron, a partial agonist of nAChR, for 1 day would affect cognitive deficits and P50 inhibition deficits in SCZ patients. We randomized 40 SCZ non-smokers into a double-blind clinical trial with four groups: placebo, 5 mg/d, 10 mg/d, and 20 mg/d of oral tropisetron. Their P50 ratios were all more than 0.5 and they took risperidone at 3-6 mg/day for at least a month before participating in the experiment. We measured the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and P50 inhibition before and one day after treatment. After one day of treatment, the total RBANS scores of the 20 mg and 5 mg tropisetron groups, and the immediate memory of the 10 mg group were significantly higher than placebo group. The P50 ratio was smaller in the 5 mg and 10 mg groups than in the placebo group (both p < 0.05) after treatment. Furthermore, the improvement in RBANS total score was correlated with increased S1 latency (p < 0.05), and the increase in immediate memory score was correlated with decreased S2 amplitude. One day of treatment with tropisetron improved both cognitive and P50 inhibition deficits, suggesting that longer term treatment with α7 nAChR agonists for these deficits in SCZ may be promising.

Effect of Cigarette and Shisha smoking on cognitive functions impairment: A cross sectional study

Objectives:

Cigarette and Shisha smoking is becoming a common practice in young generation worldwide. Since, this is a growing threat to public health, our study aims to investigate the cognitive function responses of cigarette and Shisha inhalation in adolescents.

Methods:

This retrospective cross sectional study comprised three groups, cigarette smoker, Shisha smoker, and nonsmoker control group (each n=25). All the participants were apparently healthy male volunteers aged 21-24 years. Cognitive functions were assessed by employing “Cambridge Neuropsychological Test Automated Battery”. The cognitive functions outcome variables were response time tasks (attention switching task (AST) and the percentage of correct answers pattern recognition memory (PRM) task.

Results:

Cigarette and Shisha smokers exhibited a considerable decline in cognitive performance parameters, AST mean correct latency (p=0.001), AST mean correct latency (congruent) (p=0.001), AST mean correct latency (incongruent) (p=0.001) and AST mean correct latency (switching) (p=0.001) compared to matched control group.

Conclusions:

Cigarette and Shisha smokers exhibited significant impairment in their cognitive functions. The present study findings convince that cigarette and Shisha smokers should quit smoking.

Association of Brain-Derived Neurotrophic Factor With Cognitive Function: An Investigation of Sex Differences in Patients With Type 2 Diabetes

OBJECTIVE

Although a reduction in brain-derived neurotrophic factor (BDNF) has been implicated as a cause of cognitive impairment in type 2 diabetes mellitus (T2DM), the role of sex in moderating this effect has not been explored.

METHODS

We compared the difference in serum BDNF and performance on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) between 96 men and 134 women with T2DM. We compared this with the difference in serum BDNF and performance in the control group (104 men, 144 women).

RESULTS

Patients with T2DM performed worse on most RBANS indices (η = 0.372, all p < .05); within T2DM patients, men performed worse than women on the delayed memory score (74.1 (12.1) versus 79.9 (11.5), p = .002) and on the total score (71.4 (11.5) versus 76.5 (10.8), p = .025). Serum BDNF was lower in patients with T2DM versus controls (7.5 (2.7) ng/ml versus 11.5 (2.7) ng/ml, p < .001), and in men compared with women (6.9 (2.4) versus 7.9 (2.8), p = .024). Serum BDNF levels positively correlated with delayed memory score in patients with T2DM (β = 0.19, p = .007). However, this association was only observed in women, not in men (pinteraction = 0.04). Among healthy controls, no sex differences were noted in either RBANS or BDNF levels (η = 0.04, Cohen's d < 0.163, all p > .05).

CONCLUSIONS

Our results show sex differences in poorer cognitive performance, lower BDNF concentration, and their relationship in T2DM patients, suggesting that female sex may be a protective factor for cognitive decline in T2DM patients. However, the findings should be regarded as preliminary because of the cross-sectional design and chronicity of the diabetes.

A review of peripheral brain-derived neurotrophic factor levels in alcohol-dependent patients: Current understanding

Brain-derived neurotrophic factor (BDNF) plays a crucial role in neuroplasticity of the brain, and its role in alcohol dependence has been explored in the recent past. Animal studies suggest that BDNF may function as a protective factor in transition from social drinking to an alcohol use disorder. However, clinical studies have not been able to establish similar findings and have shown mixed results. In order to obtain a comprehensive understanding, the current review aims to evaluate the existing literature on the role of BDNF in alcohol dependence. Articles were retrieved using search engines PubMed and Google Scholar. Original research studies focusing on human participants, published in English till October 2018 were reviewed. Studies which measured BDNF levels in serum or plasma or both were included in this study. A total of 13 studies were found which compared BDNF levels in alcohol-dependent patients with control population. The studies have mixed findings. Seven studies measured BDNF levels across the abstinence period, and most of the studies show improving BDNF levels across the abstinence. The current review supports the notion that BDNF plays an important role in the neuroplasticity of alcohol dependence. However, it is premature at this stage to draw conclusions that BDNF may be used as a biomarker, as there have been inconclusive findings when compared with control population. Future studies with longer follow-ups, larger sample size, comparing early and late periods of alcohol abstinence are required for better understanding of the role BDNF in alcohol dependence.

The Evaluation of Cognitive Impairment in Alcohol-Dependent Patients Through RBANS Combined With ERPs

Background: Recently, the cognitive impairment of patients with alcohol dependence has attracted more and more attention. The combination of Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and event-related potentials (ERPs) for evaluating the degree of cognitive impairment in patients with alcohol dependence has not undergone enough in-depth investigation. Method: Sixty patients with alcohol dependence were selected as alcohol-dependence group, whereas 40 healthy volunteers served as a normal control group. The original scores of the RBANS sub-items, the incubation period, and volatility of ERPs between the two groups were compared, and the correlation among the above indicators in the alcohol-dependence group was further analyzed. Results: The RBANS test showed that the original scores of speech function, attention function, delayed memory, and immediate attention in the alcohol-dependence group were significantly lower than those in the normal control group. Compared with the normal control group, the latencies of P200 and P300 in the alcohol-dependence group were significantly prolonged, and the amplitude of P200 and P300 was significantly reduced. Correlation analysis between RBANS and ERPs in alcohol-dependence group showed that immediate attention score was positively correlated with P300 and P200 amplitude, visual breadth score was positively correlated with P200 latency, and attention function score was negatively correlated with P300 latency. Conclusion: As RBANS scale was highly correlated with the results of ERPs, the combined use of these two scales may serve as an objective basis for early diagnosis of cognitive impairment in patients with alcohol dependence.

Cognitive Impairments in First-Episode Drug-Naïve Versus Medicated Depressive Patients: RBANS in a Chinese Population

Cognitive deficits are a core feature of major depressive disorder (MDD). However, there are no previous studies that directly compare cognitive performance between first-episode drug-naive depressive patients (FDDP) and medicated depressive patients (MDP). Therefore, the aim of this study was to investigate whether there were the differences in cognitive functions between FDDP and MDP. Sixty-two FDDP, 111 MDP and 90 healthy controls were enrolled in a Chinese population. Cognitive functions were assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). There were the differences in the RBANS total score (F = 26.55, p < 0.001), subscales of immediate memory (F = 3.95, p = 0.02), language (F = 54.11, p < 0.001) and delayed memory (F = 11.19, p = 0.001) among the three groups after controlling for gender, education, smoking and body mass index (BMI). These differences in the RBANS total score, subscales of language and delayed memory passed the Bonferroni corrections (all, p < 0.05). Compared to healthy controls, FDDP and MDP had poorer cognitive performance including the RBANS total score, and subscales of language and delayed memory (all, p < 0.05) after controlling for the variables. FDDP experienced greater language deficits than MDP (p < 0.05) after controlling for the variables. Education was correlated with the language score in FDDP (r = 0.61, p < 0.001). Multivariate regression analysis indicated that education was an independent contributor to the language score in FDDP (ß = 3.11, t = 5.48, p < 0.001). Our findings indicated that FDDP had poorer language performance than MDP. Moreover, education could influence the language performance in FDDP.

Effects of smoking on cognition and BDNF levels in a male Chinese population: relationship with BDNF Val66Met polymorphism

Recent studies demonstrate that brain-derived neurotrophic factor (BDNF) might be associated with nicotine addiction, and circulating BDNF is a biomarker of memory and general cognitive function. Moreover, studies suggest that a functional polymorphism of the BDNF Val66Met may mediate hippocampal-dependent cognitive functions. We aimed to explore the relationships between smoking, cognitive performance and BDNF in a normal Chinese Han population. We recruited 628 male healthy subjects, inducing 322 smokers and 306 nonsmokers, and genotyped them the BDNF Val66Met polymorphism. Of these, we assessed 114 smokers and 98 nonsmokers on the repeatable battery for the assessment of neuropsychological status (RBANS), and 103 smokers and 89 nonsmokers on serum BDNF levels. Smokers scored lower than the nonsmokers on RBANS total score (p = 0.002), immediate memory (p = 0.003) and delayed memory (p = 0.021). BDNF levels among the smokers who were Val allele carriers were correlated with the degree of cognitive impairments, especially attention, as well as with the carbon monoxide concentrations. Our findings suggest that smoking is associated with cognitive impairment in a male Chinese Han population. The association between higher BDNF levels and cognitive impairment, mainly attention in smokers appears to be dependent on the BDNF Val66Met polymorphism.

Peripheral Blood Brain-Derived Neurotrophic Factor as a Biomarker of Alzheimer's Disease: Are There Methodological Biases?

Mounting evidence that alterations in brain-derived neurotrophic factor (BDNF) levels and signaling may be involved in the etiopathogenesis of Alzheimer's disease (AD) has suggested that its blood levels could be used as a biomarker of the disease. However, higher, lower, or unchanged circulating BDNF levels have all been described in AD patients compared to healthy controls. Although the reasons for such different findings are unclear, methodological issues are likely to be involved. The heterogeneity of participant recruitment criteria and the lack of control of variables that influence circulating BDNF levels regardless of dementia (depressive symptoms, medications, lifestyle, lack of overlap between serum and plasma, and experimental aspects) are likely to bias result and prevent study comparability. The present work reviews a broad panel of factors, whose close control could help reduce the inconsistency of study findings, and offers practical advice on their management. Research directed at elucidating the weight of each of these variables and at standardizing analytical methodologies is urgently needed.

Is Perineural Invasion of Head and Neck Squamous Cell Carcinomas Linked to Tobacco Consumption?

Perineural invasion (PNI) is an underrecognized path of cancer spread, and its causes and mechanisms are poorly understood. Recent research indicates a mutual attraction of neuronal and cancer cells, largely dependent on neurotrophic factors and their receptors. Interestingly, the release of neurotrophic factors occurs upon cigarette smoke/nicotine exposure in a dose-dependent manner, and serum levels correlate with current smoking, number of smoking years, and smoking severity. Among cell types capable of neurotrophic factors secretion are lung and oral fibroblasts. In our study of 178 patients with head and neck squamous cell carcinoma, tumors of current and former smokers showed PNI significantly more often than tumors of never smokers. Moreover, PNI was a marker for aggressive tumor growth. Surprisingly, PNI was more significant for survival than p16 status. Our study warrants further research on PNI in head and neck squamous cell carcinoma with special emphasis on the impact of tobacco consumption to identify suitable candidates for therapeutic interventions.

Association of serum BDNF levels with psychotic symptom in chronic patients with treatment-resistant depression in a Chinese Han population

The neurotrophic hypothesis of depression is supported by consistent findings of lower serum BDNF levels in depressed patients. Increasing evidence shows different clinical characteristics of patients with psychotic major depression versus nonpsychotic major depression. However, the possible association between BDNF and psychotic symptoms in depression has not been investigated. We recruited 90 treatment-resistant depression (TRD) patients and 90 gender- and age-matched healthy control subjects and examined serum BDNF in both groups. Patients' depressive symptoms were assessed using the 17-item Hamilton Depression Rating Scale (HDRS-17), and psychopathological symptoms by the 18-item Brief Psychiatric Rating Scale (BPRS-18). Our results showed that BDNF levels were significantly lower in patients than controls. Correlation analysis revealed a significantly positive correlation between BDNF and the thought disturbance subscale of BPRS-18 (p < 0.05), and a trend toward a significantly positive correlation between BDNF and the BPRS-18 total score (p = 0.06). Stepwise multiple regression analyses confirmed BDNF as the influencing factor for the thought disturbance subscales of the BPRS-18. Our findings suggest that BDNF may be involved in the pathophysiology of TRD, and its associated psychotic symptoms, especially thought disturbance.

Prospective association between tobacco smoking and death by suicide: a competing risks hazard analysis in a large twin cohort with 35-year follow-up

BACKGROUND

The relationship between smoking and suicide remains controversial.

METHOD

A total of 16 282 twin pairs born before 1958 in Finland and alive in 1974 were queried with detailed health and smoking questionnaires in 1975 and 1981, with response rates of 89% and 84%. Smoking status and dose, marital, employment, and socio-economic status, and indicators of psychiatric and somatic illness were assessed at both time points. Emergent psychiatric and medical illness and vital status, including suicide determined by forensic autopsy, were evaluated over 35-year follow-up through government registries. The association between smoking and suicide was determined in competing risks hazard models. In twin pairs discordant for smoking and suicide, the prospective association between smoking and suicide was determined using a matched case-control design.

RESULTS

Smokers had a higher cumulative suicide incidence than former or never smokers. Heavy smokers had significantly higher suicide risk [hazard ratio (HR) 3.47, 95% confidence interval (CI) 2.31-5.22] than light smokers (HR 2.30, 95% CI 1.61-3.23) (p = 0.017). Compared with never smokers, smokers, but not former smokers, had increased suicide risk (HR 2.56, 95% CI 1.43-4.59), adjusting for depressive symptoms, alcohol and sedative-hypnotic use, and excluding those who developed serious somatic or psychiatric illness. In twin pairs discordant for smoking and suicide, suicide was more likely in smokers [odds ratio (OR) 6.0, 95% CI 2.06-23.8].

CONCLUSIONS

Adults who smoked tobacco were more likely to die by suicide, with a large, dose-dependent effect. This effect remained after consideration of many known predictors of suicide and shared familial effects, consistent with the hypothesis that exposure to tobacco smoke increases the risk of suicide.

Association between DBH 19bp insertion/deletion polymorphism and cognition in schizophrenia with and without tardive dyskinesia

Long-term antipsychotic treatment for schizophrenia is associated with the development of tardive dyskinesia (TD), which is involved in increased cognitive impairment. Dopamine beta-hydroxylase (DBH) gene associated with dopamine and norepinephrine systems influences cognition. Schizophrenia with TD have higher DBH activity than those without TD. This study examined whether DBH5'-insertion/deletion (-Ins/Del) polymorphism could influence cognitive function in schizophrenia with and without TD. The presence of DBH5'-Ins/Del polymorphism was determined in 345 schizophrenia with TD and 397 schizophrenia without TD. The Abnormal Involuntary Movement Scale and Repeatable Battery for Assessment of Neuropsychological Status (RBANS) were used to assess TD severity and cognition. The allele and genotype frequencies of DBH5'-Ins/Del polymorphism did not differ between patients with and without TD (both p>0.05). RBANS total score and subscales did not differ by DBH5'-Ins/Del genotype groups in patients with TD (all p>0.05). However, attention score significantly differed by DBH5'-Ins/Del genotype groups in those without TD (p<0.05). Patients without TD who were Del homozygous had significantly lower attention score than those without TD who were Ins alleles (p<0.05). Immediate memory and attention scores were lower in patients with TD than without TD (both p<0.05). This study indicated that DBH5'-Ins/Del polymorphism may not play a role in the susceptibility to TD and cognitive deficits in schizophrenia with TD, but it may influence cognitive function in schizophrenia with non-TD. Moreover, schizophrenia with TD experienced greater cognitive deficits than those with non-TD, especially in immediate memory and attention.

Increased BDNF may not be associated with cognitive impairment in heroin-dependent patients

A growing number of evidence suggests that brain-derived neurotrophic factor (BDNF) plays an important part in modulating the activities on the basis of hippocampus neural plasticity, such as learning and memory. Heroin addiction has a series of cognitive impairments that may be associated with BDNF. In this study, we explored the association of BDNF with cognitive function in heroin-dependent patients.We enrolled 86 heroin-dependent patients and 238 normal control subjects and examined their cognition by the repeatable battery for the assessment of neuropsychological status (RBANS) and serum BDNF levels in 2 groups.BDNF levels were significantly higher in patients than controls (P < .001). Cognitive scores of the RBANS showed that attention and language index (P < .05) were significantly lower in heroin-dependent patients than control groups. Unfortunately, we found no positive association between BDNF and cognitive function in patients, except that BDNF was positively associated with visuospatial/constructional index in control groups.Our findings suggest that BDNF may not be involved in the pathophysiology of heroin dependence, but more studies about cognitive impairment in heroin addiction are needed.

Effect of Smoking on Cognitive Functioning in Young Saudi Adults

BACKGROUND Smoking is the predominant form of tobacco consumption and is growing worldwide, particularly in the younger generation in the Middle-East. We aimed to determine the effects of tobacco smoking on cognitive functions among young Saudi adults. MATERIAL AND METHODS We recruited a group of cigarette smokers (N=22) and a group of controls (non-smokers) (N=30) from apparently healthy male volunteers aged 18-29 years. Cognitive function was assessed by using the Cambridge Neuropsychological Automated Battery (CANTAB). The cognitive functions outcome variables were the response time (attention-switching task [AST]), and the percentage of correct response (pattern recognition memory [PRM] task). Clinical, demographic, blood markers (brain-derived neurotrophic factor (BDNF) and apolipoprotein E) were assessed between groups. RESULTS The 2 groups were matched for age and educational status. In comparison to the control group, smokers showed significant cognitive impairments in AST-Latency (p=0.001), AST-Congruent (p=0.001), and AST-Incongruent condition (p=0.001). There was not significant difference in BDNF APOE serum level between the 2 groups. CONCLUSIONS These results indicate that attention and alertness were significantly impaired in smokers compared to non-smokers.