Soluble oligomers and fibrillar species of amyloid ß-peptide differentially affect cognitive functions and hippocampal inflammatory response.

Two major active species of ß-amyloid protein (Aß), fibrillar Aß1-42 (FAß) and soluble Aß1-42 oligomers (AßO), are known to play important roles in the pathogenesis of Alzheimer's disease. However, the differences between them are largely unknown. In this study, we explored the effects of FAß and AßO on cognitive functions and hippocampal inflammatory response through a 30-days infusion of FAß or AßO (144pmol/d) into the left lateral ventricles of the rat brain. Morris water maze showed that the impairment of learning and memory functions was much more significant in the AßO-infused rats, compared to the FAß-infused rats. AßO-induced neurodegeneration and ultrastructure damage in CA1 neurons were more remarkable than those induced by FAß. Compared to FAß, AßO exerted more potent effects on the expressions of inflammatory factors toll-like receptor 4 and TNF-α and activation of NF-κB signaling. Taken together, our results from in vivo model demonstrate that AßO is more neurotoxic than FAß, and this neurotoxicity may be related to NF-κB-medicated inflammatory response.

Individualized management of hepatic diseases in hereditary hemorrhagic telangiectasia.

Liver involvement in patients with hereditary hemorrhagic telangiectasia (HHT) has not been fully characterized in China. The clinical manifestations, imaging studies, results of treatment in six patients and symptomatic liver involvement were analyzed. Patients included three women and three men with age from 35 to 62 years old. Two patients presented with shortness of breath, one patient with anemia and splenomegaly, and one with chronic gastrointestinal bleeding; the remaining two were asymptomatic. CT and CT angiography (CTA) showed arterioportal and arteriovenous shunting in liver. CTA showed at least one enlarged hepatic artery in all patients. One patient received ligation of the enlarged arteries with subsequent disappearance of symptoms at 56-month follow-up. The patient with gastrointestinal bleeding received interventional embolotherapy and resolved; interventional therapy to embolize the enlarged hepatic arteries was unsuccessful in another patient and the patient died of heart failure and liver dysfunction 38 months later. The patient with splenomegaly received a splenectomy and bandage of an enlarged hepatic artery. One of the two patients with no symptoms died of liver dysfunction 41 months after diagnosis. The other showed abnormal liver function and ascites, and traditional Chinese medicinal herb was used with no effect 21 months later. The symptoms disappeared after systemic medical treatment. Individualized and active therapy is advantageous and proper for patients with HHT.

[Diffusion tensor imaging of elderly leukoaraiosis and its correlation with cognitive function].

OBJECTIVE: To apply diffusion tensor imaging (DTI) for investigating the correlation between leukoaraiosis (LA) lesion's fraction anisotropy (FA) as well as average diffusion coefficient (DCavg) and LA severity, so as to explore DTI changes in microstructure of white marrow with normal ordinary MRI and its correlation with cognitive function. METHODS: Sixty LA patients and 30 healthy elderly people accepted DTI examination to detect the value of DCavg and FA of LA lesion and normal white marrow. The Mini-Mental State Examination (MMSE) was used for assessing cognitive function. RESULTS: LA severity (0 grade to 3 grade) was positively associated with DCavg, i.e. the more severe was LA, the higher DCavg was (0.66 +/- 0.05 to 1.09 +/- 0.06, P < 0.05); and it was negatively associated with FA, i.e. the more severe was LA, the lower FA was (0.42 +/- 0.04 to 0.26 +/- 0.03, P < 0.05). Neuropsychology tests (Mini-Mental State Examination, MMSE) had a significant relationship with DCavg and FA of normal appearing white matter (NAWM) in LA patients (P < 0.05), especially in anterior horn (Pearson Correlation Coefficient 0.422, P < 0.05) and in centrum semiovale (Pearson Correlation Coefficient -0.495, P < 0.01). CONCLUSIONS: In DTI examination, DCavg and FA of LA displays characteristic changes. Therefore, DTI can detect the macrostructaral changes of white marrow with normal MRI and these changes are related to cognitive function.

[Experimental study of implantation of neurotropin-3 modified olfactory ensheathing cells in experimental allergic encephalomyelitis].

OBJECTIVE: To investigate the therapeutic effect of neurotrophin-3 (NT-3) modified olfactory ensheathing cell (OEC) upon experimental allergic encephalomyelitis (EAE). METHODS: OEC-NT-3 gene engineering cell, constructed by neurotrophin-3 transinfecting GEC inducted by retrovirus, was transplanted into lateral ventricle. The migration and distribution were observed and compared with control group and OEC transplantation group. Then myelin repairing and axon regeneration were evaluated from conical somatosensory evoked potential (CSEP), function score and ultrastructural morphology. RESULTS: (1) OEC-NT-3 could survive, migrate within axons and spread diffusely away from the focus at Day 28 post-transplantation; (2) as compared with other two groups, more nerve fibers, better myelin repair and more distinct myelin structure were observed in the transgene group; (3) as compared with other two groups, the latent time was obviously shortened and the amplitude higher in the transplantation group (P < 0.05); (4) the transcription level of NT-3mRNA in the transgene group was significantly higher than the GEC group and the contrast group (212.32 +/- 16.14) x 10(-2) vs. (1.98 +/- 0.19) x 10(-2), (1.23 +/- 0.13) x 10(-2) (P < 0.01). CONCLUSION: OEC-NT-3 cell expresses NT-3 stably and effectively in EAE. It may contribute to the repairing of myelin and the regeneration of axon.

Lingo-1 inhibited by RNA interference promotes functional recovery of experimental autoimmune encephalomyelitis.

Lingo-1 is a negative regulator of myelination. Repairment of demyelinating diseases, such as multiple sclerosis (MS)/experimental autoimmune encephalomyelitis (EAE), requires activation of the myelination program. In this study, we observed the effect of RNA interference on Lingo-1 expression, and the impact of Lingo-1 suppression on functional recovery and myelination/remyelination in EAE mice. Lentiviral vectors encoding Lingo-1 short hairpin RNA (LV/Lingo-1-shRNA) were constructed to inhibit Lingo-1 expression. LV/Lingo-1-shRNA of different titers were transferred into myelin oligodendrocyte glycoprotein-induced EAE mice by intracerebroventricular (ICV) injection. Meanwhile, lentiviral vectors carrying nonsense gene sequence (LVCON053) were used as negative control. The Lingo-1 expression was detected and locomotor function was evaluated at different time points (on days 1,3,7,14,21, and 30 after ICV injection). Myelination was investigated by luxol fast blue (LFB) staining.LV/Lingo-1-shRNA administration via ICV injection could efficiently down-regulate the Lingo-1 mRNA and protein expression in EAE mice on days 7,14,21, and 30 (P < 0.01), especially in the 5 × 10(8) TU/mL and 5 × 10(9) TU/mL LV/Lingo-1-shRNA groups. The locomotor function score in the LV/Lingo-1-shRNA treated groups were significantly lower than the untreated or LVCON053 group from day 7 on. The 5 × 10(8) TU/mL LV/Lingo-1-shRNA group achieved the best functional improvement (0.87 ± 0.11 vs. 3.05 ± 0.13, P < 0.001). Enhanced myelination/remyelination was observed in the 5 × 10(7) , 5 × 10(8) , 5 × 10(9) TU/mL LV/Lingo-1-shRNA groups by LFB staining (P < 0.05, P < 0.01, and P < 0.05).The data showed that administering LV/Lingo-1-shRNA by ICV injection could efficiently knockdown Lingo-1 expression in vivo, improve functional recovery and enhance myelination/remyelination. Antagonism of Lingo-1 by RNA interference is, therefore, a promising approach for the treatment of demyelinating diseases, such as MS/EAE.

Effects of fibrillar Aß(1-40) on the viability of primary cultures of cholinergic neurons and the expression of insulin signaling-related proteins.

To investigate the effects of fibrillar Aß(1-40) on the morphology and viability of cholinergic neurons and the involvement of the insulin-signaling pathway, we established primary cultures of rat basal forebrain cholinergic neurons and observed their responses to treatment with fibrillar Aß(1-40) at different concentrations for different durations. Cell morphology was examined under microscope after immunofluorescence staining for neurofilament protein, cell vitality accessed by the Methyl thiazolyl tetrazolium assay, and expressions of a panel of insulin signaling-related proteins was detected by Western blot analysis. We show here that, at low concentrations of 0.1-1.0 micromol/L, fibrillar Aß(1-40) had little effects on the cells; however, at higher concentrations of 2-10 µmicromol/L, it caused pathological changes, decreased the cell viability, and reduced the expression of insulin receptor, insulin receptor substrate-I, Protein Kinase B, and B cell lymphoma/leukemia-2 in a dose- and time-dependent manner. These results demonstrate that fibrillar Aß(1-40) not only decreases the viability of cholinergic neuron but also down regulates the expression of important proteins in the insulin signal transduction pathway. We speculate that fibrillar Aß(1-40) may contribute to the pathogenesis of Alzheimer's through disrupting the insulin signaling pathway, therefore decreasing neuronal activity and eventually leading to the apoptosis and cell loss.