Jing-Hui Song

The influence of cytochrome oxidase CYP2A6, CYP2B6, and CYP2C9 polymorphisms on the plasma concentrations of valproic acid in epileptic patients.

OBJECTIVES To investigate influences of the functional polymorphisms of Cytochrome P450 isozymes 2A6 (CYP2A6), 2B6 (CYP2B6), and 2C9 (CYP2C9) on pharmacokinetics of VPA in vivo. PATIENTS AND METHODS In the study, we analyzed the genotypes of CYP2A6, CYP2B6, and CYP2C9 and their contribution to the steady-state standardized plasma VPA concentrations in 179 subjects with epilepsy of a Northern Han Chinese population. The genotypes were detected by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS The subjects with one or two variant CYP2A6*4 alleles showed higher mean plasma VPA concentrations compared with non-*4 alleles [(3.4+/-0.4)microg kg ml(-1)mg(-1) vs. (3.6+/-0.4)microg kg ml(-1)mg(-1), p=0.0055]. A significant difference [one-way ANOVA (p=0.0203)] was also found between mean plasma VPA concentrations and the CYP2B6 genotypes. In addition, subjects with the heterozygous genotype CYP2C9*3 had higher mean plasma VPA concentrations than did those subjects with the wild-type genotype [(3.9+/-0.4)microg kg ml(-1)mg(-1) vs. (3.4+/-0.4)microg kg ml(-1)mg(-1), p=0.0001]. CONCLUSION The presently evaluated variant alleles in the CYP2A6, CYP2B6, and CYP2C9 genes may explain part of the substantial variability in VPA pharmacokinetics between different subjects.

Role of the mTOR signaling pathway in epilepsy.

Epilepsy, a common neurological disorder and cause of significant morbidity and mortality, places an enormous burden on the individual and society. Presently, most drugs for epilepsy primarily suppress seizures as symptomatic therapies but do not possess actual antiepileptogenic or disease-modifying properties. The mTOR (mammalian target of rapamycin) signaling pathway is involved in major multiple cellular functions, including protein synthesis, cell growth and proliferation and synaptic plasticity, which may influence neuronal excitability and be responsible for epileptogenesis. Intriguing findings of the frequent hyperactivation of mTOR signaling in epilepsy make it a potential mechanism in the pathogenesis as well as an attractive target for the therapeutic intervention, and have driven the significant ongoing efforts to pharmacologically target this pathway. This review explores the relevance of the mTOR pathway to epileptogenesis and its potential as a therapeutic target in epilepsy treatment by presenting the current results on mTOR inhibitors, in particular, rapamycin, in animal models of diverse types of epilepsy. Limited clinical studies in human epilepsy, some paradoxical experimental data and outstanding questions have also been discussed.

Interleukin-18 promoter polymorphisms and risk of late onset Alzheimer's disease

Pro- and anti-inflammatory cytokines play an important role in Alzheimers disease (AD), and common polymorphisms of genes controlling their production have been shown to be associated with the susceptibility to sporadic AD. Interleukin (IL)-18 is a potent pro-inflammatory cytokine of the IL-1 superfamily, and increasing evidences indicate a crucial role for it in the pathogenesis of AD. To clarify the role of IL-18 as a potential cause for AD susceptibility, we investigated the effect of two functional polymorphisms in IL-18 promoter: -607 C/A (rs1946518) and -137 G/C (rs187238) for the risk of sporadic late onset Alzheimers disease (LOAD) in a Han Chinese population of 109 patients and 109 healthy controls matched for sex and age. All 218 subjects were also genotyped for the Apolipoprotein E (ApoE) polymorphisms. The results revealed that both -607 C allele and -137 G allele were associated with an increased risk of LOAD (odds ratios/OR=1.56, P=0.04, Power=0.96 and OR=1.85, P=0.03, Power=0.80, respectively), and these associations were influenced by the presence of ApoE epsilon4 alleles. Moreover, they showed a highly significant synergistical interaction with the ApoE epsilon4 allele (OR=5.70 and 4.64, respectively). Examination of the haplotypes identified the -607 C/-137 G haplotype to increase the risk of LOAD (OR=1.62, P=0.003, Power=0.97). These findings suggest that the functional polymorphisms in IL-18 promoter may be involved in the risk of developing sporadic LOAD in the Han Chinese population.

Brain-Derived Neurotrophic Factor in Alzheimer’s Disease: Risk, Mechanisms, and Therapy

Brain-derived neurotrophic factor (BDNF) has a neurotrophic support on neuron of central nervous system (CNS) and is a key molecule in the maintenance of synaptic plasticity and memory storage in hippocampus. However, changes of BDNF level and expression have been reported in the CNS as well as blood of Alzheimer’s disease (AD) patients in the last decade, which indicates a potential role of BDNF in the pathogenesis of AD. Therefore, this review aims to summarize the latest progress in the field of BDNF and its biological roles in AD pathogenesis. We will discuss the interaction between BDNF and amyloid beta (Aβ) peptide, the effect of BDNF on synaptic repair in AD, and the association between BDNF polymorphism and AD risk. The most important is, enlightening the detailed biological ability and complicated mechanisms of action of BDNF in the context of AD would provide a future BDNF-related remedy for AD, such as increment in the production or release of endogenous BDNF by some drugs or BDNF mimics.

Polymorphisms at the β2-adrenergic receptor gene influence Alzheimer's disease susceptibility

Increasing evidence indicates that the beta2-adrenergic receptor (beta2-AR) may play an important role in Alzheimers disease (AD). We investigated the effect of two polymorphisms in the beta2-AR gene: Gly16Arg and Gln27Glu for the risk of sporadic Late Onset Alzheimers Disease (LOAD) in 109 patients and 109 healthy controls matched for sex and age in a Han Chinese population. Results revealed that both the 16Gly allele and the 27Glu allele of the beta2-AR gene were associated with an increased risk of LOAD (P=0.009, OR=1.652 and P=0.002, OR=2.846, respectively), and they also showed a highly significant interaction with the Apolipoprotein E gene (APOE) epsilon4 allele (OR=4.200 and 9.441, respectively). Examination of the haplotypes identified the Gly16Glu27 haplotype to increase the risk of LOAD (P=0.004). Our results suggest that variations in the beta2-AR gene play an important role in the pathogenesis of sporadic LOAD, and interact with the epsilon4 allele to markedly increase the LOAD risk.

Implication of IL-33 gene polymorphism in Chinese patients with Alzheimer's disease

Interleukin-33 (IL-33), a newly described member of the IL-1 family, is located on chromosome 9p24, a chromosomal region of interest in Alzheimers disease (AD) defined by many genome-wide studies. Three intronic rs1157505, rs11792633, and rs7044343 single nucleotide polymorphisms (SNPs) within IL-33 have recently been reported to be associated with risk of AD in Caucasian populations. In order to assess the involvement of the IL-33 polymorphisms in the risk of developing late onset AD (LOAD), we analyzed the genotype and allele distributions of these 3 polymorphisms in 704 Han Chinese subjects. The minor alleles of the rs11792633 polymorphism within IL-33 was significantly associated with a reduced risk of LOAD (odds ratio [OR] = 0.73, p = 0.005). Furthermore, rs11792633 polymorphism was still strongly associated with LOAD (dominant model: OR = 0.67, p = 0.015; recessive model: OR 0.57, p = 0.021; additive model: OR = 0.71, p = 0.004) after adjusting for age, gender, and the apolipoprotein E (APOE) ε4 status. Our results support the evidence that genetic variants of IL-33 affect susceptibility to LOAD in Han Chinese.

Neuropeptide Y polymorphisms and ischemic stroke in Chinese population

BACKGROUND Stroke is the second most common cause of death in developed countries and a major cause of adult disability and mortality worldwide. New data strongly suggest that neuropeptide Y (NPY) may be a candidate gene for ischemic stroke. METHODS We investigated 450 ischemic stroke patients and 423 healthy controls matched for sex and age in a Han Chinese population. Three functional polymorphisms (-883TGins/del, -602G/T and -399 T/C) located in NPY gene promoter were genotyped using DNA sequencing methods. RESULTS Of 3 NPY polymorphisms investigated in our study, the -399CC genotype (OR: 1.699, 95% CI: 1.124-2.567, P=0.011) and the -399C allele (OR: 1.254, 95% CI: 1.031-1.524, P=0.023) were more frequent among ischemic stroke patients than in controls, especially in the small vessel disease (SVD) subtype patients. The similar results were observed in multivariable logistic regression analysis. Haplotype analysis revealed that the -883ins/-399C haplotype was a risk marker for ischemic stroke (P=0.008). CONCLUSIONS The C allele of -399 T/C polymorphism in the promoter regions of NPY is an independent risk factor for ischemic stroke, suggesting that NYP system may involve in the mechanisms of stroke pathology.

Interleukin-18 promoter polymorphisms and risk of ischemic stroke

Ischemic stroke (IS) is a major cause of morbidity and mortality around the world. Interleukin-18 (IL-18) plays an important role in the pathogenesis of IS and IL-18 promoter polymorphisms have been shown to be associated with levels of expression of IL-18. We investigated the association of two functional polymorphisms in IL-18 promoter, -607C/A (rs1946518) and -137G/C (rs187238), with the risk of ischemic stroke in a Han Chinese population of 423 patients and 384 healthy controls matched for sex and age. The results revealed that the -607C allele was associated with an increased risk of IS with an odds ratios (OR) of 1.358 (P = 0.002, power = 100%) and the presence of the -137G allele was correlated with increased the risk of IS in the subtype of patients with large artery atherosclerosis (LAA) (OR = 1.583, P = 0.02, power = 94%). Patients with the -607C/-137G haplotype also had significantly increased risk of IS compared to controls (OR = 1.341, P = 0.005, power = 100%). Our findings suggest that these functional polymorphisms in the IL-18 promoter are involved in development of IS in the Han Chinese population.