[Relative analysis of platelet activation with bleeding risk in patients with primary immune thrombocytopenia]

目的

研究原发免疫性血小板减少症（ITP）患者血小板活化状态和出血程度的相关性。

方法

采用ITP特异性出血评价工具（ITP-BAT）对43例ITP患者进行出血评分及出血程度分级，应用流式细胞术检测二磷酸腺苷（ADP）激活前后血小板膜糖蛋白（GP）Ⅰb、Ⅱb/Ⅲa和P选择素表达。分析GPⅠb、GPⅡb/Ⅲa、P选择素表达与血小板计数、未成熟血小板比例的相关性；分析GPⅠb、GPⅡb/Ⅲa、P选择素表达与ITP患者出血程度的相关性，以及对中度以上出血患者风险评估的应用价值。

结果

ITP患者激活前血小板GPⅡb/Ⅲa、P选择素表达均高于正常对照组（65.69±10.73对7.16±0.99，t=4.130，P<0.001；15.43±1.41对12.55±1.03，t=2.070，P=0.043），GPⅠb表达低于正常对照组（240.11±24.93对295.11±22.15，t=2.417，P=0.020）。ITP患者ADP激活后血小板GPⅡb/Ⅲa表达高于正常对照组（133.96±12.17对39.67±4.99，t=5.256，P<0.001），而P选择素、GPⅠb表达低于正常对照组（37.09±3.94对109.77±23.66，t=3.901，P<0.001；149.06±19.14对205.73±21.00，t=2.070，P=0.043）。ADP激活后GPⅠb表达、ADP激活前后P选择素表达及ADP激活前后GPⅠb、P选择素表达比值与血小板计数相关（P<0.05）。ADP激活后P选择素表达、ADP激活前后P选择素表达比值与未成熟血小板比例相关（P<0.05）。ITP患者ADP激活后GPⅠb表达、ADP激活前后P选择素表达及ADP激活前后P选择素、GPⅡb/Ⅲa、GPⅠb表达比值在不同出血程度之间差异有统计学意义（P<0.05）。ADP激活前后GPⅠb表达比值是ITP患者中度以上出血的正性影响因素（OR=3.05，P=0.011），ADP激活前后P选择素、GPⅡb/Ⅲa表达比值是ITP患者中度以上出血的负性影响因素（OR=0.32，P=0.023；OR=0.04，P=0.006）。

结论

血小板活化指标能较准确地评估ITP患者出血程度，可以作为治疗参考指标和疗效观察指标。

Tumor-associated immune factors are associated with recurrence and metastasis in non-small cell lung cancer

Dynamic interaction between tumor cells and the microenvironment is critical for tumorigenesis, and cancer immunosurveillance plays an important role in the tumor evolution. In some tumors (such as esophageal cancer, pancreatic cancer and colorectal cancer), studies have shown that the number of tumor-infiltrating lymphocytes (TILs) has a significant relationship with the prognosis, but there is little research on the prognosis of TILs and non-small cell lung cancer (NSCLC) has been performed. Therefore, it is necessary to discover the relationship between the TILs and cytokines with NSCLC prognosis and metastasis in patients. Tumor samples were carefully examined for tissue preservation and complete follow-up. A total of 107 tumor samples from NSCLC patients with radical surgical resection were enrolled for the analysis. All samples were subjected to immunohistochemistry for detection of CD3, CD4, CD8, CD28, forkhead box protein P3 (Foxp3), cytotoxic T lymphocyte-associated protein-4, cyclooxygenase2 (COX-2), transforming growth factor β 1, interleukin-2 (IL-2), interleukin-6, interleukin-10, interleukin-12 receptor and hypoxia inducible factor 1a (HIF-1a). The number, function and location of the targets were analyzed to determine their correlation with disease-free survival (DFS) and overall survival (OS). Immunhistochemical results from 107 samples indicated that the FoxP3+ regulatory TIL (HR=1.336, P=0.031), IL-2 (HR=0.595, P=0.007) and HIF-1a (HR=1.510, P=0.002) levels in tumor cells closely correlated with DFS in a COX analysis model. FoxP3+ regulatory TILs (HR=1.566, P=0.002) significantly correlated with OS and tumor node metastasis staging. The patients were divided into two groups due to the coexpression pattern of the IL-2, FoxP3+ and HIF-1a. The high-risk group had an overall worse survival than those at low risk. We confirmed that Foxp3 expression in lymphocyte and IL-2 expression in tumor cells were associated with recurrence or transfer. Furthermore, we also observed that HIF-1a expression significantly correlated with DFS and OS.

High-Dose Linoleic Acid Activated JAK2-STAT3 Signaling Pathway Involved in Cytokine Production and Lipogenesis in Pancreatic Exocrine Cells

BACKGROUND

Linoleic acid has been implicated in the pathogenesis of acute pancreatitis. However, molecular mechanisms underlying adverse effects of large-dose linoleic acid remain unclear. Current study aimed to explore the impact of high-dose linoleic acid on the activation of Janus kinase 2 (JAK2)-signal transducers and activators of transcription 3 (STAT3) pathway, cytokine production, and lipogenesis in pancreatic exocrine cells.

METHODS

MTT assay was used to detect the viability of AR42J rat pancreatic exocrine cells, and lactate dehydrogenase assay was utilized to detect cytotoxicity. Concentrations of interleukin (IL)-6 and tumor necrosis factor (TNF)-α were detected by ELISA, and protein expression of JAK2, p-JAK2, STAT3, p- STAT3, and fatty acid synthase (FAS) was examined by Western Blot. The impact of highdose linoleic acid on JAK2-STAT3 pathway was also examined when JAK2 was inhibited by AG490, and STAT3 expression was interrupted by siRNA.

RESULTS

The cell viability of AR42J rat pancreatic exocrine cells was inhibited, and cytotoxicity was increased by high-dose linoleic acid. JAK2 and STAT3 proteins in pancreatic exocrine cells were activated by high-dose linoleic acid via phosphorylation and nuclear localization of phosphorylated STAT3. Moreover, the expression of downstream proteins in JAK2-STAT3 pathway (IL-6, TNF-α and FAS) was up-regulated by high-dose linoleic acid. The increased levels of IL-6 and TNF-α caused by high-dose linoleic acid were attenuated by JAK2 inhibitor AG490. p-JAK2 protein was up-regulated, whereas p-STAT3, STAT3 and FAS proteins were down-regulated by high-dose linoleic acid in the presence of STAT3-siRNA.

CONCLUSION

The cytotoxicity was increased and JAK2-STAT3 signaling pathway was activated by high-dose linoleic acid through cytokine production and lipogenesis in rat pancreatic exocrine cells.

[Pathology and differential diagnosis of immunotactoid glomerulopathy]

Objective: To study the morphologic changes of immunotactoid glomerulopathy and to investigate the clinical pathological features and differential diagnosis. Methods: Renal biopsy was observed under the light microscope, immunofluorescence and electron microscopy in a case of newly diagnosed immunotactoid glomerulopathy. Results: This patient clinically presented with nephrotic syndrome and hypertension, without family history of renal diseases. Light microscopy showed that diffusely massive and specific protein deposition in the glomerulus in Masson staining. Immunofluorescence revealed IgG, C3 and κ were deposited along the capillary walls and mesangial regions. Electron microscopic examination showed that a large amount of microtubule like substances and a small amount of long bar-shaped and dense crystal-like substances were deposited in the subendothelial spaces and mesangial areas. Conclusions: Light microscopy and immunofluorescence of immunotactoid glomerulopathy show no specifically pathological changes. Under electron microscope, a large amount of microtubule like substances is deposited in the glomerulus, which is the key point to distinguish this disease from other glomerular diseases. Except for the microtubule-like substances, the present case is accompanied by the deposition of long bar-shaped and dense crystal-like substance, which has not been reported in previous studies.

Correlation of the TCF7L2 (rs7903146) polymorphism with an enhanced risk of type 2 diabetes mellitus: a meta-analysis

Increasing evidence has demonstrated that a transcription factor 7-like 2 (TCF7L2) polymorphism (rs7903146) is significantly associated with type 2 diabetes mellitus (T2DM); however, limited sample size and variance of ethnicity in the studies investigating this association have led to conflicting reports regarding its role. Therefore, a comprehensive meta-analysis was conducted to quantitatively assess the association between the TCF7L2 polymorphism (rs7903146) and T2DM including published case-control studies in global populations. We searched the PubMed, EMbase, CNKI, and Wanfang databases for publications that studied correlation between TCF7L2 polymorphism (rs7903146) and risk of T2DM. Thirty-six studies from 30 eligible papers were identified. After data extraction and reference quality assessment, summary odds ratio and 95% confidence intervals (95%CI) of the TCF7L2 (rs7903146) polymorphism were calculated and combined using the fixed-effect model. Hardy-Weinberg equilibrium was evaluated to determine selection bias of the control subjects. Heterogeneity among studies was examined using the Q-test and the I² test. Publication bias in studies was assessed using Begg's plots and the Egger test. The results showed that the rs7903146 T allele of the TCF7L2 gene was positively correlated with an enhanced risk of T2DM in the allelic, heterozygote, homozygote, dominant, and recessive models, with odds ratios of 1.35 (T vs C, 95%CI = 1.31-1.39), 1.32 (CT vs CC, 95%CI = 1.27-1.38), 1.74 (TT vs CC, 95%CI = 1.63-1.87), 1.40 (TT+CT vs CC, 95%CI = 1.35-1.46), and 1.59 (TT vs CT+CC, 95%CI = 1.49-1.69), respectively. No obvious publication bias was observed using the Egger linear test.

Characterization and identification of ISSR markers associated with oil content in sea buckthorn berries

Bioactive oils extracted from sea buckthorn (Hippophae rhamnoides) berries contain highly nutritional and medicinal compounds; however, the oil contents of sea buckthorn berries are very low. Thirteen inter-simple sequence repeat (ISSR) primers were used to identify markers associated with oil content of dry pulp in 51 cultivars and lines, which clustered into three major groups based on 137 polymorphic markers. Dry pulp oil contents in 45 cultivars and lines in Group I ranged from 6.6 to 33.1%; these accessions belonged to H. rhamnoides ssp mongolica and its hybrids with H. rhamnoides ssp sinensis. Three lines (H. rhamnoides ssp mongolica) in Group II had high dry pulp oil contents (33.7 to 37.5%), whereas three lines of hybrids in Group III had low dry pulp oil contents (10.9 to 17.5%). The dry pulp oil content of H. rhamnoides ssp mongolica (27.2 ± 0.9%) was higher than that of hybrids (12.0 ± 1.2%) (P < 0.01). Four ISSR markers (881₃₄₀, 825₁₀₀₀, 817₃₈₀, and 807₁₁₀₀) had positive association with high dry pulp oil content (P < 0.01) using stepwise multiple regression analysis. The use of these ISSR markers is a potential strategy to select genotypes with high dry pulp oil content and suitable parental combinations for improvement of sea buckthorn berries.

Global DNA methylation in gonads of adult zebrafish Danio rerio under bisphenol A exposure

Altered DNA methylation is pervasively associated with changes in gene expression and signal transduction after exposure to a wide range of endocrine disrupting chemicals. As a weak estrogenic chemical, bisphenol A (BPA) has been extensively studied for reproductive toxicity. In order to explore the effects of BPA on epigenetic modification in gonads of zebrafish Danio rerio, we measured the global DNA methylation together with the gene expression of DNA methyltransferase (dnmts), glycine N-methyltransferase (gnmt), and ten-eleven translocation (tets) in gonads of D. rerio under BPA exposure by ELISA and quantitative real-time PCR method, respectively. The global level of DNA methylation was significantly decreased in ovaries after exposed to BPA for 7 days, and testes following 35-day exposure. Moreover, the global level of DNA methylation was also significantly reduced in testes after exposed to 15μg/L BPA for 7 days. Besides the alteration of the global level of DNA methylation, varying degrees of transcriptional changes of dnmts, gnmt and tets were detected in gonads of D. rerio under BPA exposure. The present study suggested that BPA might cause the global DNA demethylation in gonads of zebrafish by regulating the transcriptional changes of the DNA methylation/demethylation-associated genes (dnmts, gnmt, and tets).

Cardiomyocyte-specific TβR2 knockout mice are more susceptible to cardiac hypertrophy induced by adrenergic agonist stimulation

TGF-β signaling is shown to be involved in cardiac remodeling, but the detailed function and underlying mechanism are still incompletely understood. In this study, we generated cardiomyocyte-specific TGF-β type 2 receptor (TβR2) knockout mice to study the function of TGF-β signaling in cardiac hypertrophy. Although the mutant mice displayed no obvious physiological abnormality, they developed severer cardiac hypertrophy in response to isoproterenol (ISO) stimulation than control mice did. The expression of p-Smad2 was markedly reduced, while the concentration of p-ERK was increased in the hearts of mutant mice. In addition, we also found that cardiomyocyte-specific Smad2 knockout mice did not demonstrate cardiac phenotype as observed on TβR2 knockout mice, while inhibition of MEK-1-mediated activation of MAPK using PD98059 partially rescued the phenotype of TβR2-deleted cardiomyocytes, indicating that activation of TGF- noncanonical signaling might contribute to cardiac phenotype observed in TβR2 knockout mice. Thus, our data provided the first in vivo genetic evidence to show that TβR2 may function as an anti-hypertrophic factor of cardiac hypertrophy subjected to adrenergic stimulation, suggesting the complex role of TβR2 in cardiac hypertrophy under stimulation of different stresses.

Effect of low-dose malathion on the gonadal development of adult rare minnow Gobiocypris rarus

Malathion is an organophosphorus pesticide that extensively used in agriculture and veterinary practices. To investigate the effects of low dose malathion on rare minnow Gobiocypris rarus gonadal development, we exposed adult rare minnow to environmentally relevant concentration malathion (2 and 20μg/L) for 21 days. Gonadal histology, sex hormone levels and mRNA expressions of steroidogenic genes were investigated. Malathion at both 2 and 20μg/L significantly up-regulated rare minnow testicular weight and promoted the progression of spermatogenesis. Neither ovarian weight nor process of ovary development was markedly changed. In testis, 2μg/L malathion significantly down-regulated testosterone and 11-ketotestosterone levels, and up-regulated mRNA expression of steroidogenic genes. In ovaries, 2 and 20μg/L malathion significantly inhibited estradiol17β levels and induced testosterone levels, both in concentration dependent manners; mRNA expressions of almost all the detected ovarian steroidogenic genes were up-regulated. The present result suggested that malathion even at low dose could pose a potential threat to adult rare minnow gonadal development.

Effects of bisphenol A on lipid metabolism in rare minnow Gobiocypris rarus

As one of the most abundant endocrine disrupting compounds (EDCs), bisphenol A (BPA) exists ubiquitously in an aquatic environment. Many studies on fish have focused on the reproductive toxicity effects of BPA. However, few has involved the effects of BPA on lipid metabolism. To evaluate the effects of BPA on lipid metabolism, we determine the hepato-somatic index, triglyceride contents in the liver and serum, the activities of acetyl-CoA carboxylase (ACC), fatty acid synthase (FASN), carnitine palmitoyltransferase (CPT1), and glycerol-3-phosphate acyltransferase (GPAT) enzymes and the mRNA expression of acaca, acacb, fasn, gpat1 and cpt1α in Gobiocypris rarus after exposure to BPA for 28days. BPA induced increasing tendency of triglyceride contents in male fish, possibly due to up-regulated lipid synthesis. Although in this process, fatty acid β-oxidation was up-regulated, it might be compensated by increasing lipogenesis. Our result also revealed that the GPAT enzyme might play a key role in lipid metabolism disturbance by BPA in females. Besides, the effect of BPA on the fatty acid β-oxidation pathway might be gender-dependent in G. rarus. Further studies are needed to investigate BPA's effects on the signaling pathway of lipid metabolism.

Adolescent exposure to cocaine increases anxiety-like behavior and induces morphologic and neurochemical changes in the hippocampus of adult rats

Repeated exposure to cocaine during adolescence may affect both physical and psychological conditions in the brain, and increase the risk of psychiatric disorders and addiction behaviors in adulthood. Adolescence represents a critical development period for the hippocampus. Moreover, different regions of the hippocampus are involved in different functions. Dorsal hippocampus (dHP) has been implicated in learning and memory, whereas ventral hippocampus (vHP) plays an important role in emotional processing. In this study, the rats that were exposed to cocaine during adolescence (postnatal days, P28-P42) showed higher anxiety-like behavior in the elevated plus maze test in adulthood (P80), but displayed normal spatial learning and memory in the Morris water maze test. Furthermore, repeated exposure to cocaine during adolescence lead to alterations in morphology of pyramidal neurons, activities of astrocytes, and levels of proteins that involved in synaptic transmission, apoptosis, inflammation and addiction in both dHP and vHP of adult rats. These findings suggest that repeated exposure to cocaine during adolescence in rats may elicit morphologic and neurochemical changes in the hippocampus when the animals reach adulthood. These changes may contribute to the increased susceptibility for psychiatric disorders and addiction seen in adults.

Socioeconomic inequalities in dental caries among 5-year-olds in four Chinese provinces

OBJECTIVE

To explore socioeconomic inequalities in dental caries among 5-year-olds in four Chinese provinces.

METHODS

This study used data from 1,732 children living in Guangxi, Hubei, Jilin and Shanxi who participated in the Third National Oral Health Survey in 2005. Questionnaires were completed by parents to collect information on family socioeconomic position (parental education and household income) and children's dental behaviours (toothbrushing frequency, sugar intake frequency and last dental visit). Children were clinically examined for dental caries, which was reported using the dmft index. Socioeconomic inequalities in children's caries experience were assessed in negative binomial regression models.

RESULTS

There were significant gradients in children's dmft by household income. Children's dmft increased from 2.63 in the highest income group to 4.70 in the lowest income group. However, parental education was not significantly related to childhood dental caries.

CONCLUSION

Clear social gradients in caries experience of deciduous teeth were found by household income but not parental education.

Impairment of Endothelial Cell Function Induced by Hemoglobin A(1c) and the Potential Mechanisms

OBJECTIVE

Hemoglobin A(1c) (HbA(1c)) concentrations reflect glycemic control and diabetic complications. However, there is little evidence supporting the pathological role of HbA(1c) in the development and progression of diabetic complications. We investigated the impact of HbA(1c) on endothelial cell function and the potential mechanisms.

METHODS

The effects of HbA(1c) on the viability and migration of human umbilical vein endothelial cells (HUVECs) were measured by the Cell Counting Kit-8 and a wound healing scratch assay, respectively. Production of nitric oxide (NO) and reactive oxygen species was measured by the nitrate reductase colorimetric method and flow cytometry, respectively. The expression of endothelial nitric oxide synthase (eNOS) mRNA was quantitated by reverse-transcriptase PCR. The expression of eNOS, p-AMPK, and NOX4 proteins was detected by Western blot.

RESULTS

High concentrations of HbA(1c) reduced the viability and migration of HUVECs in a dose- and time-dependent manner. High concentrations of HbA(1c) inhibited production of NO but increased production of ROS. Incubation with increasing concentrations of HbA(1c) downregulated the expression of eNOS mRNA, decreased expression of eNOS and p-AMPK, and upregulated expression of NOX4.

CONCLUSION

These findings provide direct evidence that HbA(1c) is involved in the development and progression of the cardiovascular complications of diabetes.

The inhibition of high-voltage-activated calcium current by activation of MrgC11 involves phospholipase C-dependent mechanisms

High-voltage-activated (HVA) calcium channels play an important role in synaptic transmission. Activation of Mas-related G-protein-coupled receptor subtype C (MrgC; mouse MrgC11, rat homolog rMrgC) inhibits HVA calcium current (ICa) in small-diameter dorsal root ganglion (DRG) neurons, but the intracellular signaling cascade underlying MrgC agonist-induced inhibition of HVA ICa in native DRG neurons remains unclear. To address this question, we conducted patch-clamp recordings in MrgA3-eGFP-wild-type mice, in which most MrgA3-eGFP(+) DRG neurons co-express MrgC11 and can be identified for recording. We found that the inhibition of HVA ICa by JHU58 (0.001-100nM, a dipeptide, MrgC-selective agonist) was significantly reduced by pretreatment with a phospholipase C (PLC) inhibitor (U73122, 1μM), but not by its inactive analog (U73343) or vehicle. Further, in rats that had undergone spinal nerve injury, pretreatment with intrathecal U73122 nearly abolished the inhibition of mechanical hypersensitivity by intrathecal JHU58. The inhibition of HVA ICa in MrgA3-eGFP(+) neurons by JHU58 (100nM) was partially reduced by pretreatment with a Gβγ blocker (gallein, 100μM). However, applying a depolarizing prepulse and blocking the Gαi and Gαs pathways with pertussis toxin (PTX) (0.5μg/mL) and cholera toxin (CTX) (0.5μg/mL), respectively, had no effect. These findings suggest that activation of MrgC11 may inhibit HVA ICa in mouse DRG neurons through a voltage-independent mechanism that involves activation of the PLC, but not Gαi or Gαs, pathway.

Activation of p38 MAPK in the rostral ventromedial medulla by visceral noxious inputs transmitted via the dorsal columns may contribute to pelvic organ cross-sensitization in rats with endometriosis

Whether visceral organ cross-sensitization is involved in endometriosis-associated pain remains elusive. Previous studies have shown that visceral noxious stimuli may trigger a cascade of signal transductions in the rostral ventromedial medulla (RVM) via the spinal dorsal column (DC) pathway and the RVM plays a critical role in the descending control of visceral nociception. In the current study, we hypothesized that the p38 mitogen-activated protein kinase (MAPK) activation in the RVM by noxious visceral inputs from ectopic growths via the DC was involved in the development of pelvic organ cross-sensitization in established endometriosis. A rat model of experimental endometriosis was established. To examine ectopic growths-to-colon cross-sensitization, graded colorectal distention (CRD) was performed and abdominal withdrawal reflex (AWR) scores were recorded in female rats at 8weeks after the uterine or fat (control) auto-transplantation. Western blot study was carried out to examine the phosphorylated form and the total level of p38 MAPK protein in the RVM. Our results showed that lesions of bilateral DCs immediately following uterine or fat auto-transplantation in female rats significantly attenuated the later development of ectopic growths-to-colon cross-sensitization and the increased p38 MAPK activation in the RVM, as compared to sham DC lesions. Furthermore, intra-RVM microinjection of a p38 MAPK inhibitor (SB 203580), but not vehicle, in female rats with established endometriosis significantly attenuated ectopic growths-to-colon cross-sensitization and the increased activation of p38 MAPK in the RVM. These findings suggest that the noxious inputs from ectopic growths may activate p38 MAPK in the RVM via the DC, which may contribute to the development of ectopic growths-to-colon cross-sensitization in established endometriosis.

Development of functional in vivo imaging of cerebral lenticulostriate artery using novel synchrotron radiation angiography

The lenticulostriate artery plays a vital role in the onset and development of cerebral ischemia. However, current imaging techniques cannot assess the in vivo functioning of small arteries such as the lenticulostriate artery in the brain of rats. Here, we report a novel method to achieve a high resolution multi-functional imaging of the cerebrovascular system using synchrotron radiation angiography, which is based on spatio-temporal analysis of contrast density in the arterial cross section. This method provides a unique tool for studying the sub-cortical vascular elasticity after cerebral ischemia in rats. Using this technique, we demonstrated that the vascular elasticity of the lenticulostriate artery decreased from day 1 to day 7 after transient middle cerebral artery occlusion in rats and recovered from day 7 to day 28 compared to the controls (p < 0.001), which paralleled with brain edema formation and inversely correlated with blood flow velocity (p < 0.05). Our results demonstrated that the change of vascular elasticity was related to the levels of brain edema and the velocity of focal blood flow, suggesting that reducing brain edema is important for the improvement of the function of the lenticulostriate artery in the ischemic brain.

Collateral circulation prevents masticatory muscle impairment in rat middle cerebral artery occlusion model

The rat suture middle cerebral artery occlusion (MCAO) is a frequently used animal model for investigating the mechanisms of ischemic brain injury. During suture MCAO, transection of the external carotid artery (ECA) potentially restrains blood flow and impairs masticatory muscle and other ECA-supported territories, consequently influencing post-operation animal survival. This study was aimed at investigating the effect of ECA transection on the hemodynamic alterations using a novel synchrotron radiation (SR) angiography technique and magnetic resonance imaging in live animals. Fifteen male adult Sprague-Dawley rats were used in this study. Animals underwent MCAO, in which the ECA was transected. SR angiography was performed before and after MCAO. Rats then underwent magnetic resonance imaging (MRI) to detect the tissue lesion both intra- and extra-cranially. Animals with SR angiography without other manipulations were used as control. High-resolution cerebrovascular morphology was analyzed using a novel technique of SR angiography. The masticatory muscle lesion was further examined by hematoxylin and eosin staining. MRI and histological results showed that there was no masticatory muscle lesion at 1, 7 and 28 days following MCAO with ECA transection. In normal condition, the ECA and its branch external maxillary artery were clearly detected. Following ECA transection, the external maxillary artery was still observed and the blood supply appeared from the anastomotic branch from the pterygopalatine artery. SR angiography further revealed the inter-relationship of hemisphere extra- and intra-cranial vasculature in the rat following MCAO. Transection of the ECA did not impair masticatory muscles in rat suture MCAO. Interrupted blood flow could be compensated by the collateral circulation from the pterygopalatine artery.

Blood versus crystalloid cardioplegia for pediatric cardiac surgery: a meta-analysis

OBJECTIVE

Blood and crystalloid cardioplegia are the main myocardial protective solutions used in pediatric cardiac surgery. However, the effectiveness of these two solutions on myocardial metabolism, reperfusion injury and clinical outcomes in pediatric patients is still under debate. The purpose of this meta-analysis was to compare the efficacy of these two cardioplegia solutions in pediatric cardiac surgery.

METHODS

Keyword searches were performed on PUBMED, EMBASE and The Cochrane Library for randomized, controlled, clinical studies which were primarily comparing blood and crystalloid cardioplegia in pediatric cardiac surgery and provided data of postoperative cardiac troponin I (cTnI), lactate, mechanical ventilation time, length of intensive care unit (ICU) stay and inotropic support. Databases were searched from 1966 to June 2013 and were restricted to peer-reviewed English language publications of human subjects. We summarized the combined results of the data as mean difference (MD, when outcome measurements were made on the same scale) or standard mean difference (SMD, when the studies assess the same outcome with different scales), with 95% confidence intervals.

RESULTS

Five studies were identified, with a total of 323 patients. Lactate level after cardiopulmonary bypass (CPB) was significantly lower after blood cardioplegia compared with crystalloid cardioplegia (SMD 1.09, 95%CI 0.12 to 2.06, p=0.03); cTnI release postoperatively at 4-6 h (MD 0.92 ng/ml, 95%CI -0.13 to 1.97, p=0.09), 12 h (MD 0.2 ng/ml, 95% CI -0.43 to 0.84, p=0.53) and 24 h (MD 0.98 ng/ml, 95%CI -0.26 to 2.22, p=0.12) was not significantly different between the groups; ventilation duration (MD 5.15 hours, 95%CI -7.51 to 17.81, p=0.42) and length of ICU stay (SMD -0.3, 95%CI -0.80 to 0.21, p=0.25) were not significantly different between the groups either.

CONCLUSION

Myocardial metabolism was better in the blood cardioplegia group compared with the crystalloid cardioplegia group. However, there was no evidence of improvement in myocardial damage or clinical outcome for either cardioplegia solution.

Genetic tuning of the novel avian influenza A(H7N9) virus during interspecies transmission, China, 2013

A novel avian influenza A(H7N9) virus causing human infection emerged in February 2013 in China. To elucidate the mechanism of interspecies transmission, we compared the signature amino acids of avian influenza A(H7N9) viruses from human and non-human hosts and analysed the reassortants of 146 influenza A(H7N9) viruses with full genome sequences. We propose a genetic tuning procedure with continuous amino acid substitutions and reassorting that mediates host adaptation and interspecies transmission. When the early influenza A(H7N9) virus, containing ancestor haemagglutinin (HA) and neuraminidase (NA) genes similar to A/Shanghai/05 virus, circulated in waterfowl and transmitted to terrestrial poultry, it acquired an NA stalk deletion at amino acid positions 69 to 73. Then, receptor binding preference was tuned to increase the affinity to human-like receptors through HA G186V and Q226L mutations in terrestrial poultry. Additional mammalian adaptations such as PB2 E627K were selected in humans. The continual reassortation between H7N9 and H9N2 viruses resulted in multiple genotypes for further host adaptation. When we analysed a potential association of mutations and reassortants with clinical outcome, only the PB2 E627K mutation slightly increased the case fatality rate. Genetic tuning may create opportunities for further adaptation of influenza A(H7N9) and its potential to cause a pandemic.

Seroepidemiology of Middle East respiratory syndrome (MERS) coronavirus in Saudi Arabia (1993) and Australia (2014) and characterisation of assay specificity

The pseudoparticle virus neutralisation test (ppNT) and a conventional microneutralisation (MN) assay are specific for detecting antibodies to Middle East respiratory syndrome coronavirus (MERS-CoV) when used in seroepidemiological studies in animals. Genetically diverse MERS-CoV appear antigenically similar in MN tests. We confirm that MERS-CoV was circulating in dromedaries in Saudi Arabia in 1993. Preliminary data suggest that feral Australian dromedaries may be free of MERS-CoV but larger confirmatory studies are needed.

Highly pathogenic avian influenza A H5N1 and pandemic H1N1 virus infections have different phenotypes in Toll-like receptor 3 knockout mice

Toll-like receptors (TLRs) play an important role in innate immunity to virus infections. We investigated the role of TLR3 in the pathogenesis of H5N1 and pandemic H1N1 (pH1N1) influenza virus infections in mice. Wild-type mice and those defective in TLR3 were infected with influenza A/HK/486/97 (H5N1) or A/HK/415742/09 (pH1N1) virus. For comparison, mice defective in the gene for myeloid differential factor 88 (MyD88) were also infected with the viruses, because MyD88 signals through a TLR pathway different from TLR3. Survival and body weight loss were monitored for 14 days, and lung pathology, the lung immune-cell profile, viral load and cytokine responses were studied. H5N1-infected TLR3(-/-) mice had better survival than H5N1-infected WT mice, evident by significantly faster regain of body weight, lower viral titre in the lung and fewer pathological changes in the lung. However, this improved survival was not seen upon pH1N1 infection of TLR3(-/-) mice. In contrast, MyD88(-/-) mice had an increased viral titre and decreased leukocyte infiltration in the lungs after infection with H5N1 virus and poorer survival after pH1N1 infection. In conclusion, TLR3 worsens the pathogenesis of H5N1 infection but not of pH1N1 infection, highlighting the differences in the pathogenesis of these two viruses and the different roles of TLR3 in their pathogenesis.

Diallyl disulfide inhibits proliferation and transdifferentiation of lung fibroblasts through induction of cyclooxygenase and synthesis of prostaglandin E₂

Platelet-derived growth factor-BB (PDGF-BB) and transforming growth factor-β1 (TGF-β1) are critically involved in idiopathic pulmonary fibrosis by inducing the proliferation and transdifferentiation of lung fibroblasts. In the present study, we examined the impact of diallyl disulfide (DADS), a garlic-derived compound, on such pathological conditions. DADS showed profound inhibitory effects on the PDGF-BB-induced proliferation of human and mouse lung fibroblasts. DADS also abrogated the TGF-β1-induced expression of α-smooth muscle actin, type I collagen and fibronectin. Following treatment with DADS, the expression of cyclooxygenase-2 (COX-2) and the synthesis of prostaglandin E₂ (PGE₂) were found to be markedly enhanced, which in turn led to elevated cAMP levels in lung fibroblasts. Notably, the effect of DADS was largely abolished in the presence of either COX inhibitor indomethacin or siRNA-targeting COX-2, or in the absence of the PGE₂ receptor EP2, supporting an essential role for the COX-2-PGE₂-cAMP autocrine loop. Furthermore, we demonstrated that the upregulated expression of COX-2 was a result of increased level of histone 3 acetylation at COX-2 locus in DADS-treated cells. Together, these results suggest that DADS, by inducing COX-2 expression, may have therapeutic potential in treating lung fibrosis.

Subretinal transplantation of rat MSCs and erythropoietin gene modified rat MSCs for protecting and rescuing degenerative retina in rats

For degenerative retinal diseases, like the acquired form exemplified by age-related macular degeneration (AMD), there is currently no cure. This study was to explore a stem cell therapy and a stem cell based gene therapy for sodium iodate (SI)-induced retinal degeneration in rats. Three cell types, i.e., rat mesenchymal stem cells (rMSCs) alone, erythropoietin (EPO) gene modified rMSCs (EPO-rMSCs) or doxycycline (DOX) inducible EPO expression rMSCs (Tet-on EPO-rMSCs), were transplanted into the subretinal spaces of SI-treated rats. The rMSCs were prepared for transplantation after 3 to 5 passages or modified with EPO gene. During the 8 weeks after the transplantation, the rats treated with rMSCs alone or with two types of EPO-rMSCs were all monitored with fundus examination, fundus fluorescein angiography (FFA) and electroretinogram. The transplantation efficiency of donor cells was examined for their survival, integration and differentiation. Following the transplantation, labeled donor cells were observed in subretinal space and adopted RPE morphology. EPO concentration in vitreous and retina of SI-treated rats which were transplanted with EPO-rMSCs or Tet-on EPO-rMSCs was markedly increased, in parallel with the improvement of retinal morphology and function. These findings suggest that rMSCs transplantation could be a new therapy for degenerative retinal diseases since it can protect and rescue RPE and retinal neurons, while EPO gene modification to rMSCs could be an even better option.

Comparison of intensity-dependent inhibition of spinal wide-dynamic range neurons by dorsal column and peripheral nerve stimulation in a rat model of neuropathic pain

BACKGROUND

Spinal cord stimulation (SCS) and peripheral nerve stimulation (PNS) are thought to reduce pain by activating a sufficient number of large myelinated (Aβ) fibres, which in turn initiate spinal segmental mechanisms of analgesia. However, the volume of neuronal activity and how this activity is associated with different treatment targets is unclear under neuropathic pain conditions.

METHODS

We sought to delineate the intensity-dependent mechanisms of SCS and PNS analgesia by in vivo extracellular recordings from spinal wide-dynamic range neurons in nerve-injured rats. To mimic therapeutic SCS and PNS, we used bipolar needle electrodes and platinum hook electrodes to stimulate the dorsal column and the tibial nerve, respectively. Compound action potentials were recorded to calibrate the amplitude of conditioning stimulation required to activate A-fibres and thus titrate the volume of activation.

RESULTS

Dorsal column stimulation (50 Hz, five intensities) inhibited the windup (a short form of neuronal sensitization) and the C-component response of wide-dynamic range neurons to graded intracutaneous electrical stimuli in an intensity-dependent manner. Tibial nerve stimulation (50 Hz, three intensities) also suppressed the windup in an intensity-dependent fashion but did not affect the acute C-component response.

CONCLUSIONS

SCS and PNS may offer similar inhibition of short-term neuronal sensitization. However, only SCS attenuates spinal transmission of acute noxious inputs under neuropathic pain conditions. Our findings begin to differentiate peripheral from spinal-targeted neuromodulation therapies and may help to select the best stimulation target and optimum therapeutic intensity for pain treatment.

Aryl hydrocarbon receptor exogenous ligand 3-methylchoranthrene inhibited endometrial cancer cells proliferation

OBJECTIVE

Endometrial cancer (EC) is the most prevalent gynecologic malignancy among women worldwide. Increasing evidence has disclosed the potential role of aryl hydrocarbon receptor (AhR) in the cancer development; however, little is known about its roles in the EC development. In the present study, we evaluated AhR expression in EC tissues as well as cell lines, and investigated the effects of AhR knockdown and exogenous ligand 3-methylchoranthrene (3-MC) on EC cells proliferation and invasion using Ishikawa and ECC-1 cells lines.

MATERIALS AND METHODS

In this study, tissue microarray and immunohistochemistry were used to investigate the expression and localization of AhR in EC tissues. RT-PCR and Western blot were performed to detect the AhR expression. AhR specific siRNA was used to knockdown the AhR expression. MTT and transwell assay were carried out to study the EC cells proliferation and invasion, respectively.

RESULTS

Our results showed that AhR was highly expressed in the EC tissues and cell lines when compared with its expression in the normal endometrial tissues. AhR siRNA significantly decreased (p < 0.05) AhR protein expression in both Ishikawa and ECC-1 cells. Knockdown of AhR did not alter EC cells proliferation and invasion. However, 3-MC dose-dependently inhibited (p < 0.05) EC cells proliferation via AhR-mediated pathway.

CONCLUSIONS

The results from the current application will provide critical information on roles of 3-MC/AhR pathway in mediating EC growth, which could be useful for future therapeutic intervention in this lethal human disease.

Sitagliptin and pioglitazone provide complementary effects on postprandial glucose and pancreatic islet cell function

AIMS

The effects of sitagliptin and pioglitazone, alone and in combination, on α- and β-cell function were assessed in patients with type 2 diabetes.

METHODS

Following a 6-week diet/exercise period, 211 patients with HbA1c of 6.5-9.0% and fasting plasma glucose of 7.2-14.4 mmol/l were randomized (1 :1 :1 : 1) to sitagliptin, pioglitazone, sitagliptin + pioglitazone or placebo. At baseline and after 12 weeks, patients were given a mixed meal followed by frequent blood sampling for measurements of glucose, insulin, C-peptide and glucagon.

RESULTS

After 12 weeks, 5-h glucose total area under the curve (AUC) decreased in all active treatments versus placebo; reduction with sitagliptin + pioglitazone was greater versus either monotherapy. The 5-h insulin total AUC increased with sitagliptin versus all other treatments and increased with sitagliptin + pioglitazone versus pioglitazone. The 3-h glucagon AUC decreased with sitagliptin versus placebo and decreased with sitagliptin + pioglitazone versus pioglitazone or placebo. Φ(s), a measure of dynamic β-cell responsiveness to above-basal glucose concentrations, increased with either monotherapy versus placebo and increased with sitagliptin + pioglitazone versus either monotherapy. The insulin sensitivity index (ISI), a composite index of insulin sensitivity, improved with pioglitazone and sitagliptin + pioglitazone versus placebo. The disposition index, a measure of the relationship between β-cell function and insulin sensitivity, improved with all active treatments versus placebo.

CONCLUSIONS

Sitagliptin and pioglitazone enhanced β-cell function (increasing postmeal Φ(s)), and sitagliptin improved α-cell function (decreasing postmeal glucagon) after 12 weeks in patients with type 2 diabetes. Through these complementary mechanisms of action, the combination of sitagliptin and pioglitazone reduced postmeal glucose more than either treatment alone.

Seroepidemiology for MERS coronavirus using microneutralisation and pseudoparticle virus neutralisation assays reveal a high prevalence of antibody in dromedary camels in Egypt, June 2013

We describe a novel spike pseudoparticle neutralisation assay (ppNT) for seroepidemiological studies on Middle East respiratory syndrome coronavirus (MERS-CoV) and apply this assay together with conventional microneutralisation (MN) tests to investigate 1,343 human and 625 animal sera. The sera were collected in Egypt as a region adjacent to areas where MERS has been described, and in Hong Kong, China as a control region. Sera from dromedary camels had a high prevalence of antibody reactive to MERS-CoV by MERS NT (93.6%) and MERS ppNT (98.2%) assay. The antibody titres ranged up to 1,280 and higher in MN assays and 10,240 and higher in ppNT assays. No other investigated species had any antibody reactivity to MERS-CoV. While seropositivity does not exclude the possibility of infection with a closely related virus, our data highlight the need to attempt detection of MERS-CoV or related coronaviruses in dromedary camels. The data show excellent correlation between the conventional MN assay and the novel ppNT assay. The newly developed ppNT assay does not require Biosafety Level 3 containment and is thus a relatively high-throughput assay, well suited for large-scale seroepidemiology studies which are needed to better understand the ecology and epidemiology of MERS-CoV.

Tropism and innate host responses of a novel avian influenza A H7N9 virus: an analysis of ex-vivo and in-vitro cultures of the human respiratory tract

BACKGROUND

Since March, 2013, an avian-origin influenza A H7N9 virus has caused severe pneumonia in China. The aim of this study was to investigate the pathogenesis of this new virus in human beings.

METHODS

We obtained ex-vivo cultures of the human bronchus, lung, nasopharynx, and tonsil and in-vitro cultures of primary human alveolar epithelial cells and peripheral blood monocyte-derived macrophages. We compared virus tropism and induction of proinflammatory cytokine responses of two human influenza A H7N9 virus isolates, A/Shanghai/1/2013 and A/Shanghai/2/2013; a highly pathogenic avian influenza H5N1 virus; the highly pathogenic avian influenza H7N7 virus that infected human beings in the Netherlands in 2003; the 2009 pandemic influenza H1N1 virus, and a low pathogenic duck H7N9 virus that was genetically different to the human disease causing A H7N9 viruses.

FINDINGS

Both human H7N9 viruses replicated efficiently in human bronchus and lung ex-vivo cultures, whereas duck/H7N9 virus failed to replicate in either. Both human A H7N9 viruses infected both ciliated and non-ciliated human bronchial epithelial cells and replicated to higher titres than did H5N1 (p<0.0001 to 0.0046) and A/Shanghai/1/2013 replicated to higher titres than did H7N7 (p=0.0002-0.01). Both human A H7N9 viruses predominantly infected type II alveolar epithelial cells and alveolar macrophages in the human lung and replicated to higher titres than did H5N1 (p<0.0001 to 0.0078); A/Shanghai/1/2013 replicated to higher titres than did H1N1 (p=0.0052-0.05) and H7N7 (p=0.0031-0.0151). Human H7N9 viruses were less potent inducers of proinflammatory cytokines compared with H5N1 virus.

INTERPRETATION

Collectively, the results suggest that the novel H7N9 viruses are better adapted to infect and replicate in the human conducting and lower airways than are other avian influenza viruses, including H5N1, and pose an important pandemic threat.

FUNDING

Area of Excellence Scheme of the University Grants Committee (AoE/M-12/96), Hong Kong Special Administrative Region.

Resistance to neuraminidase inhibitors conferred by an R292K mutation in a human influenza virus H7N9 isolate can be masked by a mixed R/K viral population

We characterized the A/Shanghai/1/2013 virus isolated from the first confirmed human case of A/H7N9 disease in China. The A/Shanghai/1/2013 isolate contained a mixed population of R (65%; 15/23 clones) and K (35%; 8/23 clones) at neuraminidase (NA) residue 292, as determined by clonal sequencing. A/Shanghai/1/2013 with mixed R/K at residue 292 exhibited a phenotype that is sensitive to zanamivir and oseltamivir carboxylate by the enzyme-based NA inhibition assay. The plaque-purified A/Shanghai/1/2013 with dominant K292 (94%; 15/16 clones) showed sensitivity to zanamivir that had decreased by >30-fold and to oseltamivir carboxylate that had decreased by >100-fold compared to its plaque-purified wild-type counterpart possessing dominant R292 (93%, 14/15 clones). In Madin-Darby canine kidney (MDCK) cells, the plaque-purified A/Shanghai/1/2013-NAK292 virus exhibited no reduction in viral titer under conditions of increasing concentrations of oseltamivir carboxylate (range, 0 to 1,000 µM) whereas the replication of the plaque-purified A/Shanghai/1/2013-NAR292 and the A/Shanghai/2/2013 viruses was completely inhibited at 250 µM and 31.25 µM of oseltamivir carboxylate, respectively. Although the plaque-purified A/Shanghai/1/2013-NAK292 virus exhibited lower NA enzyme activity and a higher Km for 2'-(4-methylumbelliferryl)-α-d-N-acetylneuraminic acid than the wild-type A/Shanghai/1/2013-NAR292 virus, the A/Shanghai/1/2013-NAK292 virus formed large plaques and replicated efficiently in vitro. Our results confirmed that the NA R292K mutation confers resistance to oseltamivir, peramivir, and zanamivir in the novel human H7N9 viruses. Importantly, detection of the resistance phenotype may be masked in the clinical samples containing a mixed population of R/K at NA residue 292 in the enzyme-based NA inhibition assay.

IMPORTANCE

The neuraminidase (NA) inhibitors oseltamivir and zanamivir are currently the front-line therapeutic options against the novel H7N9 influenza viruses, which possess an S31N mutation that confers resistance to the M2 ion channel blockers. It is therefore important to evaluate the sensitivity of the clinical isolates to NA inhibitors and to monitor for the emergence of resistant variants. We characterized the A/Shanghai/1/2013 (H7N9) isolate which contained a mixed population of R/K at NA residue 292. While the clinical isolate exhibited a phenotype of sensitivity to NA inhibitors using the enzyme-based NA inhibition assay, the plaque-purified A/Shanghai/1/2013 virus with dominant K292 was resistant to zanamivir, peramivir, and oseltamivir. Resistance to NA inhibitors conferred by the R292K mutation in a human influenza virus H7N9 isolate can be masked by a mixed R/K viral population, and this should be taken into consideration while monitoring antiviral resistance in patients with H7N9 infection.

Infectivity, transmission, and pathology of human-isolated H7N9 influenza virus in ferrets and pigs

The emergence of the H7N9 influenza virus in humans in Eastern China has raised concerns that a new influenza pandemic could occur. Here, we used a ferret model to evaluate the infectivity and transmissibility of A/Shanghai/2/2013 (SH2), a human H7N9 virus isolate. This virus replicated in the upper and lower respiratory tracts of the ferrets and was shed at high titers for 6 to 7 days, with ferrets showing relatively mild clinical signs. SH2 was efficiently transmitted between ferrets via direct contact, but less efficiently by airborne exposure. Pigs were productively infected by SH2 and shed virus for 6 days but were unable to transmit the virus to naïve pigs or ferrets. Under appropriate conditions, human-to-human transmission of the H7N9 virus may be possible.

Tropism of and innate immune responses to the novel human betacoronavirus lineage C virus in human ex vivo respiratory organ cultures

Since April 2012, there have been 17 laboratory-confirmed human cases of respiratory disease associated with newly recognized human betacoronavirus lineage C virus EMC (HCoV-EMC), and 7 of them were fatal. The transmissibility and pathogenesis of HCoV-EMC remain poorly understood, and elucidating its cellular tropism in human respiratory tissues will provide mechanistic insights into the key cellular targets for virus propagation and spread. We utilized ex vivo cultures of human bronchial and lung tissue specimens to investigate the tissue tropism and virus replication kinetics following experimental infection with HCoV-EMC compared with those following infection with human coronavirus 229E (HCoV-229E) and severe acute respiratory syndrome coronavirus (SARS-CoV). The innate immune responses elicited by HCoV-EMC were also investigated. HCoV-EMC productively replicated in human bronchial and lung ex vivo organ cultures. While SARS-CoV productively replicated in lung tissue, replication in human bronchial tissue was limited. Immunohistochemistry revealed that HCoV-EMC infected nonciliated bronchial epithelium, bronchiolar epithelial cells, alveolar epithelial cells, and endothelial cells. Transmission electron microscopy showed virions within the cytoplasm of bronchial epithelial cells and budding virions from alveolar epithelial cells (type II). In contrast, there was minimal HCoV-229E infection in these tissues. HCoV-EMC failed to elicit strong type I or III interferon (IFN) or proinflammatory innate immune responses in ex vivo respiratory tissue cultures. Treatment of human lung tissue ex vivo organ cultures with type I IFNs (alpha and beta IFNs) at 1 h postinfection reduced the replication of HCoV-EMC, suggesting a potential therapeutic use of IFNs for treatment of human infection.

The evolutionary dynamics of influenza A virus adaptation to mammalian hosts

Few questions on infectious disease are more important than understanding how and why avian influenza A viruses successfully emerge in mammalian populations, yet little is known about the rate and nature of the virus' genetic adaptation in new hosts. Here, we measure, for the first time, the genomic rate of adaptive evolution of swine influenza viruses (SwIV) that originated in birds. By using a curated dataset of more than 24 000 human and swine influenza gene sequences, including 41 newly characterized genomes, we reconstructed the adaptive dynamics of three major SwIV lineages (Eurasian, EA; classical swine, CS; triple reassortant, TR). We found that, following the transfer of the EA lineage from birds to swine in the late 1970s, EA virus genes have undergone substantially faster adaptive evolution than those of the CS lineage, which had circulated among swine for decades. Further, the adaptation rates of the EA lineage antigenic haemagglutinin and neuraminidase genes were unexpectedly high and similar to those observed in human influenza A. We show that the successful establishment of avian influenza viruses in swine is associated with raised adaptive evolution across the entire genome for many years after zoonosis, reflecting the contribution of multiple mutations to the coordinated optimization of viral fitness in a new environment. This dynamics is replicated independently in the polymerase genes of the TR lineage, which established in swine following separate transmission from non-swine hosts.

Real-time imaging of mouse lenticulostriate artery following brain ischemia

Detection of microvascular changes in experimental stroke models is limited by current technologies. Using state-of-the-art synchrotron radiation (SR), we explored the feasibility of detecting the normal morphological variations of lenticulostriate arteries (LSAs) and the changes to LSAs following middle cerebral artery occlusion (MCAO). Cerebral microvessels of ICR mice were imaged with synchrotron radiation microangiography using nonionic iodine and barium sulfate as contrast agents. Using SR we reproducibly observed the detailed cerebral microvasculature of LSAs arising from the origin of middle cerebral artery (MCA) with a resolution of approximately 5 micrometers, at least a 20-fold greater resolution compared to CT or MRI imaging. Notably, SR microangiography was able to reveal ischemia/reperfusion induced leakage in the lenticulostriate artery territory. To our knowledge this is the first time that the three-dimensional morphology of LSAs and real time visualization of LSA hemorrhage have been characterized in live mice. This work demonstrates that SR microangiography can provide a unique tool for furthering experimental stroke research to examine the efficacy of neuroprotective therapies on parameters such as angiogenesis and vascular integrity.

Delayed administration of a PTEN inhibitor BPV improves functional recovery after experimental stroke

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) inhibitors administered prior to or immediately after experimental stroke confer acute neuroprotection. However, it remains unclear if delayed treatment with a PTEN inhibitor improves long-term functional recovery after stroke. We addressed the issue in this study. Adult male mice were subjected to 1h of middle cerebral artery occlusion (MCAO) followed by treatment with a well-established PTEN inhibitor BPV or saline daily for 14 days, starting at 24h after MCAO. Functional recovery was assessed with behavioral tests and acute infarct volumes were analyzed histologically. Delayed BPV treatment did not reduce infarction during the acute phase, but significantly improved long-term functional recovery after MCAO. Since PTEN is a critical intrinsic inhibitory factor in axonal regeneration, we further examined BPV effects on axonal densities following MCAO using bielschowsky silver staining and immunohistochemistry with antibodies against myelin basic protein. Delayed BPV treatment significantly increased axon densities in the ischemic brain at 14 days after MCAO. Moreover, PTEN expression persistently remained high in the ischemic brain over 14 days after MCAO, and BPV treatment increased post-ischemic activation of Akt and mTOR in the ischemic brain. Akt and mTOR activation are the well-established cascades downstream to PTEN inhibition and have been shown to contribute to post-injury axonal regrowth in response to PTEN inhibition. Consistently, in an in vitro neuronal ischemia model, BPV enhanced axonal outgrowth of primary cortical neurons after oxygen-glucose deprivation and the enhancing effects were abolished by Akt/mTOR inhibition. In conclusion, delayed BPV treatment improved functional recovery from experimental stroke possibly via enhancing axonal growth and Akt/mTOR activation contributed to BPV-enhanced post-stroke axon growth.