Suming Zhang

Lipoxin A4 inhibits the production of proinflammatory cytokines induced by β-amyloid in vitro and in vivo

Studies increasingly indicate that inflammation induced by β-amyloid (Aβ) contributes to the progression of Alzheimers disease (AD). How to inhibit the enhanced production of proinflammatory cytokines stimulated by Aβ is an important research subject for the treatment of AD. In this study, we investigated the inhibitory effect and the molecular mechanism of the lipoxin A(4) (LXA(4)) on the production of interleukin-1β (IL-1β) and tumor necrosis factorα (TNFα) induced by β-amyloid in the cortex and hippocampus of mice, and in Aβ-stimulated BV2 cells, a mouse microglial cell line. LXA(4) down-regulated the protein expression of IL-1β and TNFα, attenuated the gene expressions of IL-1β and TNFα, inhibited the degradation of IκBα, inhibited translocation of NF-κB p65 subunit into the nucleus induced by β-amyloid in the cortex and hippocampus of mice, and in Aβ-stimulated BV2 cells, and the inhibitory effects were dose dependently elevated. Our findings suggest that LXA(4) inhibits the production of IL-1β and TNFα induced by β-amyloid in the cortex and hippocampus of mice, and in BV2 microglial cells via the NF-κB signal pathway.

Fine structure analysis and sintering properties of Si-doped hydroxyapatite

Si-doped hydroxyapatite (Si-HA) has been intensively investigated as a promising bone biomaterial because of the biomineralization and bone formation benefit from silicon addition. In the current work, Si-HA samples were synthesized by the aqueous precipitation method. The sintering property of Si-HA was studied in terms of phase composition and transition, which was influenced by the Si doping percentage and sintering temperature. The results indicate that all the as-prepared and sintered low Si doping samples (Si% ≤ 1.6 wt%) possess HA phases; while the high Si doping samples (Si% ≥ 2 wt%) present amorphous phases as prepared, and largely or even completely transform to β-tricalcium phosphate (β-TCP) phase after sintering at 1250 °C. The Rietveld refinement on x-ray diffraction patterns was conducted to determine the particle sizes, microstrain factors and anisotropic distributions. According to the refined results, the calculated anisotropic particle sizes correspond to the observations made by transmission electron microscopy. The microstrains also present anisotropic distributions in all refinements. The accurate variation in the fine structure of Si-HA has been studied by the improved refinements after considering the anisotropic distribution.

Intracranial Hypertension Syndrome in Systemic Lupus Erythematosus： Clinical Analysis and Review of the Literature

In order to better understand the clinical manifestation of systemic lupus erythematosus (SLE) with intracranial hypertension syndrome (IHS), we analyzed the clinical features and treatment of a typical SLE patient with IHS. SLE is one of the most unpredictable autoimmune diseases involving multiple organ systems that is defined clinically and associated with antibodies directed against cell nuclei. IHS is an uncommon manifestation of neuropsychiatric SLE (NPSLE) and is characterized by an elevated intracranial pressure, papilledema, and headache with occasional abducens nerve paresis, absence of a space-occupying lesion or ventricular enlargement, and normal cerebrospinal fluid chemical and hematological constituents. IHS has been reported in a few sporadic cases in patients with SLE worldwide, but rarely has been reported in China. In this study, a 34-year-old female SLE patient with IHS was reported and pertinent literature reviewed. The clinical presentation, image logical features, and investigatory findings were discussed.SummaryIn order to better understand the clinical manifestation of systemic lupus erythematosus (SLE) with intracranial hypertension syndrome (IHS), we analyzed the clinical features and treatment of a typical SLE patient with IHS. SLE is one of the most unpredictable autoimmune diseases involving multiple organ systems that is defined clinically and associated with antibodies directed against cell nuclei. IHS is an uncommon manifestation of neuropsychiatric SLE (NPSLE) and is characterized by an elevated intracranial pressure, papilledema, and headache with occasional abducens nerve paresis, absence of a space-occupying lesion or ventricular enlargement, and normal cerebrospinal fluid chemical and hematological constituents. IHS has been reported in a few sporadic cases in patients with SLE worldwide, but rarely has been reported in China. In this study, a 34-year-old female SLE patient with IHS was reported and pertinent literature reviewed. The clinical presentation, image logical features, and investigatory findings were discussed.

Proliferation and differentiation of neural stem cells co-cultured with cerebral microvascular endothelial cells after oxygen-glucose deprivation

Various stem cells, including neural stem cells (NSCs), have been extensively studied in stroke models, but how to increase neuronal differentiation rate of NSCs remains unresolved, particularly in a damaged environment. The purpose of this study was to investigate the effects of cerebral microvascular endothelial cells (CMECs) on the neurogenesis of NSCs with or without oxygen-glucose deprivation (OGD). The NSCs acquired from primary culture were immunostained to prove cell purity. Survival and proliferation of NSCs were determined after the co-culture with CMECs for 7 days. After removing the CMECs, NSCs were randomly divided into two groups as follows: OGD and non-OGD groups. Both groups were maintained in differentiation culture for 4 days to evaluate the differentiation rate. Mouse embryo fibroblast (MEF) cells co-cultured with NSCs served as control group. NSCs co-cultured with CMECs had an increase in size (on the 7th day: 89.80±26.12 μm vs. 73.08±15.01 μm, P<0.001) (n=12) and number [on the 7th day: 6.33±5.61/high power objective (HP) vs. 2.23±1.61/HP, P<0.001] (n=12) as compared with those co-cultured with MEF cells. After further differentiation culture for 4 days, NSCs co-cultured with CMECs had an increase in neuronal differentiation rate in OGD and non-OGD groups, but not in the control group (15.16% and 16.07% vs. 8.81%; both P<0.001) (n=6). This study provided evidence that OGD could not alter the effects of CMECs in promoting the neuronal differentiation potential of NSCs. These findings may have important implications for the development of new cell therapies for cerebral vascular diseases.SummaryVarious stem cells, including neural stem cells (NSCs), have been extensively studied in stroke models, but how to increase neuronal differentiation rate of NSCs remains unresolved, particularly in a damaged environment. The purpose of this study was to investigate the effects of cerebral microvascular endothelial cells (CMECs) on the neurogenesis of NSCs with or without oxygen-glucose deprivation (OGD). The NSCs acquired from primary culture were immunostained to prove cell purity. Survival and proliferation of NSCs were determined after the co-culture with CMECs for 7 days. After removing the CMECs, NSCs were randomly divided into two groups as follows: OGD and non-OGD groups. Both groups were maintained in differentiation culture for 4 days to evaluate the differentiation rate. Mouse embryo fibroblast (MEF) cells co-cultured with NSCs served as control group. NSCs co-cultured with CMECs had an increase in size (on the 7th day: 89.80±26.12 μm vs. 73.08±15.01 μm, P<0.001) (n=12) and number [on the 7th day: 6.33±5.61/high power objective (HP) vs. 2.23±1.61/HP, P<0.001] (n=12) as compared with those co-cultured with MEF cells. After further differentiation culture for 4 days, NSCs co-cultured with CMECs had an increase in neuronal differentiation rate in OGD and non-OGD groups, but not in the control group (15.16% and 16.07% vs. 8.81%; both P<0.001) (n=6). This study provided evidence that OGD could not alter the effects of CMECs in promoting the neuronal differentiation potential of NSCs. These findings may have important implications for the development of new cell therapies for cerebral vascular diseases.

Effects of Allopurinol on Arterial Stiffness: A Meta-Analysis of Randomized Controlled Trials.

Background Several studies have tested the effects of allopurinol on arterial stiffness, but the results have been inconclusive. We aimed to conduct a meta-analysis to investigate the impacts of allopurinol treatment on arterial stiffness, as measured by pulse wave velocity (PWV) and augmentation index (AIx). Material/Methods Randomized controlled trials (RCTs) assessing the effects of allopurinol on arterial stiffness were identified through searching PubMed, Web of Science, EMBASE, the Cochrane Library for Central Register of Clinical Trials, and China National Knowledge Infrastructure up to December 2015. The primary endpoints were the change of PWV and AIx after allopurinol treatment. The weighted mean difference (WMD) or standardized mean difference (SMD) and the 95% confidence interval (CI) of each study were pooled for meta-analysis. Results A total of 11 RCTs met the inclusion criteria and were included in the final meta-analysis. Eight RCTs with 1,111 patients were pooled for PWV; eight RCTs with 397 patients were pooled for PWV. Allopurinol administration did not significantly change PWV (WMD=−0.19 m/s, 95% CI: −0.49 to 0.12, Z=1.21, p=0.23), but significantly reduced AIx (SMD=−0.34, 95% CI: −0.54 to −0.14, Z=3.35, p=0.0008). Conclusions Although our meta-analysis showed some favorable effects of allopurinol treatment on improving AIx, its impact on arterial stiffness must be tested in more large-scale RCTs.

Role of leukaemia inhibitory factor in the induction of pluripotent stem cells in mice

iPS (induced pluripotent stem) cells can be induced from somatic cells in mice by genetic manipulation. Most previously established mouse iPS cell lines have been derived using feeder layers supplemented with exogenous LIF (leukaemia inhibitory factor). Although a feeder‐free induction system has been developed in recent studies, LIF is still required for reprogramming, but its role in the generation of mouse iPS cells has remained elusive. In this study, we investigated its contribution to the induction of pluripotency. Our results showed that LIF activates AP (alkaline phosphatase) through a c‐Myc‐dependent mechanism. Moreover, it acts as a protective factor during the transition from AP‐positive colonies to Oct3/4‐positive cells. These findings illustrate a mechanism by which LIF may integrate signalling into reprogramming.

Transient folate deprivation in combination with small-molecule compounds facilitates the generation of somatic cell-derived pluripotent stem cells in mice

Induced pluripotent stem cells (iPSCs) can be propagated indefinitely, while maintaining the capacity to differentiate into all cell types in the body except for the extra-embryonic tissues. This iPSC technology not only represents a new way to use individual-specific stem cells for regenerative medicine but also constitutes a novel method to obtain large numbers of disease-specific cells for biomedical research. However, the low efficiency of reprogramming and genomic integration of oncogenes and viral vectors limit the potential application of iPSCs. Chemical-induced reprogramming offers a novel approach to generating iPSCs. In this study, a new combination of small-molecule compounds (SMs) (sodium butyrate, A-83-01, CHIR99021, Y-27632) under conditions of transient folate deprivation was used to generate iPSC. It was found that transient folate deprivation combined with SMs was sufficient to permit reprogramming from mouse embryonic fibroblasts (MEFs) in the presence of transcription factors, Oct4 and Klf4, within 25 days, replacing Sox2 and c-Myc, and accelerated the generation of mouse iPSCs. The resulting cell lines resembled mouse embryonic stem (ES) cells with respect to proliferation rate, morphology, pluripotency-associated markers and gene expressions. Deprivation of folic acid, combined with treating MEFs with SMs, can improve the inducing efficiency of iPSCs and reduce their carcinogenicity and the use of exogenous reprogramming factors.SummaryInduced pluripotent stem cells (iPSCs) can be propagated indefinitely, while maintaining the capacity to differentiate into all cell types in the body except for the extra-embryonic tissues. This iPSC technology not only represents a new way to use individual-specific stem cells for regenerative medicine but also constitutes a novel method to obtain large numbers of disease-specific cells for biomedical research. However, the low efficiency of reprogramming and genomic integration of oncogenes and viral vectors limit the potential application of iPSCs. Chemical-induced reprogramming offers a novel approach to generating iPSCs. In this study, a new combination of small-molecule compounds (SMs) (sodium butyrate, A-83-01, CHIR99021, Y-27632) under conditions of transient folate deprivation was used to generate iPSC. It was found that transient folate deprivation combined with SMs was sufficient to permit reprogramming from mouse embryonic fibroblasts (MEFs) in the presence of transcription factors, Oct4 and Klf4, within 25 days, replacing Sox2 and c-Myc, and accelerated the generation of mouse iPSCs. The resulting cell lines resembled mouse embryonic stem (ES) cells with respect to proliferation rate, morphology, pluripotency-associated markers and gene expressions. Deprivation of folic acid, combined with treating MEFs with SMs, can improve the inducing efficiency of iPSCs and reduce their carcinogenicity and the use of exogenous reprogramming factors.

Effect of VEGF on neural differentiation of human embryonic stem cells in vitro.

The effects of vascular endothelial growth factor (VEGF) on neural differentiation of human embryonic stem cells (hESCs) in vitro and the possible mechanism were observed. The hESCs lines, TJMU1 and TJMU2, were established and stored by our laboratory. hESCs differentiated into neuronal cells through embryonic body formation. In this induction process, hESCs were divided into three groups: group A, routine induction; group B, routine induction+10 ng/mL VEGF; group C, routine induction+10 ng/mL VEGF+10 ng/mL VEGFR2/Fc. OCT4, Nestin and GFAP in each group were detected by RT-PCR, and the cells expressing Nestin and GFAP were counted by immunofluorescence. The percentage of Nestin positive cells in group B was significantly higher than in groups A and C, while the percentage of GFAP positive cells in group B was significantly lower than in groups A and C (P<0.01). There was no significant difference between groups A and C (P>0.05). It was concluded that VEGF, via VEGFR2, stimulated the neural differentiation of hESCs in vitro.SummaryThe effects of vascular endothelial growth factor (VEGF) on neural differentiation of human embryonic stem cells (hESCs) in vitro and the possible mechanism were observed. The hESCs lines, TJMU1 and TJMU2, were established and stored by our laboratory. hESCs differentiated into neuronal cells through embryonic body formation. In this induction process, hESCs were divided into three groups: group A, routine induction; group B, routine induction+10 ng/mL VEGF; group C, routine induction+10 ng/mL VEGF+10 ng/mL VEGFR2/Fc. OCT4, Nestin and GFAP in each group were detected by RT-PCR, and the cells expressing Nestin and GFAP were counted by immunofluorescence. The percentage of Nestin positive cells in group B was significantly higher than in groups A and C, while the percentage of GFAP positive cells in group B was significantly lower than in groups A and C (P<0.01). There was no significant difference between groups A and C (P>0.05). It was concluded that VEGF, via VEGFR2, stimulated the neural differentiation of hESCs in vitro.

Protective effects of overexpression of bcl-xl gene on local cerebral infarction in transgenic mice undergoing permanent occlusion of middle cerebral artery

In order to investigate the protective effects of the overexpression of bcl-xl gene on local cerebral infarction in the transgenic mice subject to permanent occlusion of middle cerebral artery, the models of bcl-xl transgenic mice were established and subjected to cerebral infarction by intraluminal occlusion of the middle cerebral artery. The infarct volume and the neurological scores were observed and comparison between the wild type mice and the transgenic mice was made. It was found that the infarct volume and the neurological scores in the transgenic mice were significantly decreased as compared with those in the wild type mice. It was suggested that the overexpression of bcl-xl gene in transgenic mice could reduce the infarct volume and improve the neurological function of the mice.SummaryIn order to investigate the protective effects of the overexpression of bcl-xl gene on local cerebral infarction in the transgenic mice subject to permanent occlusion of middle cerebral artery, the models of bcl-xl transgenic mice were established and subjected to cerebral infarction by intraluminal occlusion of the middle cerebral artery. The infarct volume and the neurological scores were observed and comparison between the wild type mice and the transgenic mice was made. It was found that the infarct volume and the neurological scores in the transgenic mice were significantly decreased as compared with those in the wild type mice. It was suggested that the overexpression of bcl-xl gene in transgenic mice could reduce the infarct volume and improve the neurological function of the mice.

Delayed administration of guanosine improves long‑term functional recovery and enhances neurogenesis and angiogenesis in a mouse model of photothrombotic stroke

Guanosine (GUO) is neuroprotective when administered acutely for the treatment of cerebral ischemia. The aim of the present study was to investigate whether delayed administration of GUO improved long-term functional recovery following stroke, as well as to explore the potential underlying mechanisms. GUO (8 mg/kg) or a vehicle was administered intraperitoneally for 7 consecutive days beginning 24 h prior to photothrombosis-induced stroke in male C57/B6J mice. Behaviour tests were performed at days 1, 3, 7, 14 and 28 post-stroke. Infarct volume was measured using Nissl staining at day 7 post-stroke. Neurogenesis and angiogenesis were evaluated by co-labelling bromodeoxyuridine (BrdU) with doublecortin (DCX), neuronal nuclei (NeuN) and von Willebrand factor, in immunohistochemical studies. Brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) levels in the ipsilesional brain at day 28 post-stroke were detected by western blot analysis. Delayed administration of GUO did not reduce infarct volume or affect neurological function at day 7 post-stroke; however, it did improve functional recovery from day 14 post-stroke, when compared with the vehicle group. GUO significantly increased the number of BrdU+ and BrdU+/DCX+ cells in the subventricular zone and subgranular zone at all examined time points, the number of Brdu+/NeuN+ cells in the peri-infarction region at days 14 and 28 post-stroke and microvessel density in the peri-infarction region at day 28 post-stroke compared with the vehicle group. In addition, the BDNF and VEGF levels in the ipsilesional brain were significantly elevated. Delayed administration of GUO at 24 h post-stroke enhanced neurogenesis and angiogenesis, and increased BDNF and VEGF levels, which likely contributes to long-term functional recovery following stroke.