Hui-Dong Tang

PPARγ Agonist Curcumin Reduces the Amyloid-β-Stimulated Inflammatory Responses in Primary Astrocytes

Alzheimers disease (AD) is the most common age-related neurodegenerative disorder. Accumulating data indicate that astrocytes play an important role in the neuroinflammation related to the pathogenesis of AD. It has been shown that microglia and astrocytes are activated in AD brain and amyloid-beta (Abeta) can increase the expression of cyclooxygenase 2 (COX-2), interleukin-1, and interleukin-6. Suppressing the inflammatory response caused by activated astrocytes may help to inhibit the development of AD. Curcumin is a major constituent of the yellow curry spice turmeric and proved to be a potential anti-inflammatory drug in arthritis and colitis. There is a low age-adjusted prevalence of AD in India, a country where turmeric powder is commonly used as a culinary compound. Curcumin has been shown to suppress activated astroglia in amyloid-beta protein precursor transgenic mice. The real mechanism by which curcumin inhibits activated astroglia is poorly understood. Here we report that the expression of COX-2 and glial fibrillary acidic protein were enhanced and that of peroxisome proliferator-activated receptor gamma (PPARgamma) was decreased in Abeta(25-35)-treated astrocytes. In line with these results, nuclear factor-kappaB translocation was increased in the presence of Abeta. All these can be reversed by the pretreatment of curcumin. Furthermore, GW9662, a PPARgamma antagonist, can abolish the anti-inflammatory effect of curcumin. These results show that curcumin might act as a PPARgamma agonist to inhibit the inflammation in Abeta-treated astrocytes.

Plasma metabolite profiles of Alzheimer's disease and mild cognitive impairment.

Previous studies have demonstrated altered metabolites in samples of Alzheimers disease (AD) patients. However, the sample size from many of them is relatively small and the metabolites are relatively limited. Here we applied a comprehensive platform using ultraperformance liquid chromatography-time-of-flight mass spectrometry and gas chromatography-time-of-flight mass spectrometry to analyze plasma samples from AD patients, amnestic mild cognitive impairment (aMCI) patients, and normal controls. A biomarker panel consisting of six plasma metabolites (arachidonic acid, N,N-dimethylglycine, thymine, glutamine, glutamic acid, and cytidine) was identified to discriminate AD patients from normal control. Another panel of five plasma metabolites (thymine, arachidonic acid, 2-aminoadipic acid, N,N-dimethylglycine, and 5,8-tetradecadienoic acid) was able to differentiate aMCI patients from control subjects. Both biomarker panels had good agreements with clinical diagnosis. The 2 panels of metabolite markers were all involved in fatty acid metabolism, one-carbon metabolism, amino acid metabolism, and nucleic acid metabolism. Additionally, no altered metabolites were found among the patients at different stages, as well as among those on anticholinesterase medication and those without anticholinesterase medication. These findings provide a comprehensive global plasma metabolite profiling and may contribute to making early diagnosis as well as understanding the pathogenic mechanism of AD and aMCI.

Disrupted functional brain connectivity and its association to structural connectivity in amnestic mild cognitive impairment and Alzheimer's disease.

Although anomalies in the topological architecture of whole-brain connectivity have been found to be associated with Alzheimer’s disease (AD), our understanding about the progression of AD in a functional connectivity (FC) perspective is still rudimentary and few study has explored the function-structure relations in brain networks of AD patients. By using resting-state functional MRI (fMRI), this study firstly investigated organizational alternations in FC networks in 12 AD patients, 15 amnestic mild cognitive impairment (aMCI) patients, and 14 age-matched healthy aging subjects and found that all three groups exhibit economical small-world network properties. Nonetheless, we found a decline of the optimal architecture in the progression of AD, represented by a more localized modular organization with less efficient local information transfer. Our results also show that aMCI forms a boundary between normal aging and AD and represents a functional continuum between healthy aging and the earliest signs of dementia. Moreover, we revealed a dissociated relationship between the overall FC and structural connectivity (SC) in AD patients. In this study, diffusion tensor imaging tractography was used to map the structural network of the same individuals. The decreased FC-SC coupling may be indicative of more stringent and less dynamic brain function in AD patients. Our findings provided insightful implications for understanding the pathophysiological mechanisms of brain dysfunctions in aMCI and AD patients and demonstrated that functional disorders can be characterized by multimodal neuroimaging-based metrics.

Cognitive impairment using education‐based cutoff points for CMMSE scores in elderly Chinese people of agricultural and rural Shanghai China

Cui G‐H, Yao Y‐H, Xu R‐F, Tang H‐D, Jiang G‐X, Wang Y, Wang G, Chen S‐D, Cheng Q. Cognitive impairment using education‐based cutoff points for CMMSE scores in elderly Chinese people of agricultural and rural Shanghai China.
Acta Neurol Scand: 2011: 124: 361–367.
© 2011 John Wiley & Sons A/S.

Association Study of Clusterin Polymorphism rs11136000 With Late Onset Alzheimer’s Disease in Chinese Han Population

Objective: We conducted a case–control study to investigate whether clusterin polymorphism (rs11136000) was associated with late-onset Alzheimer’s disease in Chinese Han population. Methods: Polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) assay was performed on genotype rs11136000 and APOEε4 in 127 patients with late-onset Alzheimer’s disease and 143 control individuals. Previous published data from other Chinese samples was also included for further meta-analysis. Results: APOEε4 was demonstrated to increase the risk of Alzheimer’s disease in Chinese population (odds ratio = 2.35, 95% confidence interval: 1.40-3.96). There is no significant association between clusterin rs11136000 with late-onset sporadic AD in our small cohort. However, meta-analysis revealed significant allele and genotype differences between Alzheimer’s disease and controls following a recessive model. Conclusion: Clusterin (rs11136000) was associated with Alzheimer’s disease in Chinese Han population.

Four novel mutations in the GCH1 gene of Chinese patients with dopa-responsive dystonia

Mutation detection in the guanosine triphosphate cyclohydrolase I gene (GCH1) was performed from 4 female patients with dopa‐responsive dystonia (DRD). DNA sequencing revealed the presence of four novel mutations including c.2T>C(M1T), c.239G>A(S80N), c.245T>C(L82P), and IVS5+3 del AAGT. These four mutations were not found in 100 genetically unrelated healthy controls with the same ethnic background band. In all 3 childhood‐onset patients, DRD started in the legs, and missense mutations were located in the coding region of GCH1. Deletion mutation in the fifth exon–intron boundary of GCH1 was detected in the adult‐onset patient. Although the data presented here do not provide sufficient evidence to establish a genotype–phenotype correlation of DRD, it is important to know the clinic features and genetic defects of DRD patients, which will help prenatal diagnosis, early diagnosis, evaluate the prognosis, and facilitate causal therapy with levodopa.

CALHM1 P86L Polymorphism is a Risk Factor for Alzheimer's Disease in the Chinese Population

We conducted a case-control study to determine the prevalence of the CALHM1 P86L polymorphism (rs2986017) in patients with Alzheimers disease (AD) in the Chinese population of mainland China, and also to clarify whether this polymorphism is a risk factor for AD. Fourteen heterozygous P86L carriers were identified among 198 AD patients. One control subject was also found to be a P86L heterozygous carrier. The allelic frequencies of the AD patients and control subjects were found to be significantly different. Our study indicates that the CALHM1-P86L polymorphism is associated with AD in the ethnic Chinese Han.

Association study of TREM2 polymorphism rs75932628 with late-onset Alzheimer’s disease in Chinese Han population

Abstract Objective: We conducted a case–control study to investigate whether TREM2 polymorphism (rs75932628-T) was associated with late onset Alzheimer’s disease in Chinese Southern Han population. Methods: PCR-restriction fragment length polymorphism assay was performed to genotype rs75932628 in 279 cases with late onset Alzheimer’s diseases patients and 346 control subjects in Shanghai and Nanjing. Results: There was no rs75932628-T variant detected in our sample. However, APOEϵ4 was shown closely associated with the risk of Alzheimer’s disease (Chi-square = 60·288, P = 0·000). Conclusion: Our study suggested that TREM2 (rs75932628-T) was rare in Chinese Han population. Further association studies with large samples are needed to further study the association of TREM2 with late-onset Alzheimer’s disease.

Genetic Polymorphisms in Sigma-1 Receptor and Apolipoprotein E Interact to Influence the Severity of Alzheimers Disease

Apolipoprotein E (APOE) ε4 allele and sigma-1 receptor (SIGMAR1) c.5C (Q2P) polymorphisms have been acknowledged as risk factors for developing Alzheimers disease (AD). However, whether these polymorphisms influence the disease process is unclear. Therefore, two cohorts with a clinical diagnosis of AD were recruited, a postmortem confirmed Australian cohort (82 cases) from the Australian Brain Bank Network, and a Chinese cohort with detailed clinical assessments recruited through an epidemiology study in Shanghai and through the neurology department outpatients clinic of Shanghai Ruijin Hospital (330 cases). SIGMAR1 Q2P and APOE genotyping was performed on all cases. Dementia severity in the Chinese cohort was assessed using MMSE scores, and the stages of senile plaques and neurofibrillary tangles (NFT) assessed in the Australian cohort. Associations between SIGMAR1 Q2P and APOE genotypes and disease severity were assessed using SPSS. Results confirmed that APOE 4 allele associated with increased NFT stages and cognitive decline, with carriers with one APOE ε2 or ε3 allele often having better clinical outcomes compared to carriers with none or two ε2 or ε3 alleles respectively. SIGMAR1 c.5C polymorphism alone did not associate with MMSE score variability in Chinese or with pathological stages in Caucasians. However, the association studies revealed a significant genetic interaction between the APOE ε4 allele and SIGMAR1 2P carriers in both populations, i.e., in APOE non ε4 allele carriers, SIGMAR1 2P variant had increased cognitive dysfunction and more advanced stages of NFT. Our data demonstrate that SIGMAR1 and APOE interact to influence AD severity across ethnic populations.

Validation of the Chinese Version of Addenbrooke's Cognitive Examination-Revised for Screening Mild Alzheimer's Disease and Mild Cognitive Impairment

Background/Aims: As a suitable test to screen for Alzheimers disease (AD) or mild cognitive impairment (MCI), studies to validate the Chinese version of Addenbrookes Cognitive Examination-Revised (ACE-R) are rare. Methods: A total of 151 subjects were recruited and the neuropsychological assessments were employed. One-way analysis of variance and Bonferroni correction were used to compare scores of different psychometric scales. Intraclass correlation coefficient (ICC) and Cronbachs coefficient α were used to evaluate the reliability of psychometric scales. The validity of ACE-R to screen for mild AD and amnestic subtype of MCI (a-MCI) was assessed by receiver operating characteristic (ROC) curves. Results: The Chinese ACE-R had good reliability (inter-rater ICC = 0.994; test-retest ICC = 0.967) as well as reliable internal consistency (Cronbachs coefficient α = 0.859). With its cutoff of 67/68, the sensitivity (0.920) and specificity (0.857) were lower than for the Mini-Mental State Examination (MMSE) cutoff (sensitivity 1.000 and specificity 0.937) to screen for mild AD. However, the sensitivity of ACE-R to screen for a-MCI was superior to the MMSE with a cutoff of 85/86. The specificity of ACE-R was lower than that of the MMSE to screen for a-MCI. The area under the ROC curve of ACE-R was much larger than that of the MMSE (0.836 and 0.751) for detecting a-MCI rather than mild AD. Conclusion: The Chinese ACE-R is a reliable assessment tool for cognitive impairment. It is more sensitive and accurate in screening for a-MCI rather than for AD compared to the MMSE.