Radiotherapy Utilization and Outcomes on a Contemporary Trial for Pediatric High-Risk Hodgkin Lymphoma Study

PURPOSE/OBJECTIVE(S)

Contemporary trials in pediatric Hodgkin lymphoma (cHL) evaluate strategies to reduce radiotherapy (RT) utilization while maintaining excellent progression-free survival (PFS). An alternative strategy is to irradiate selective sites at higher risk of relapse, and/or use proton therapy (PT) to minimize exposure to healthy tissue. We investigated the use of PT and photon therapy (XRT) and associated early outcomes among patients receiving involved site RT (ISRT) to high-risk sites on the Children's Oncology Group (COG) trial AHOD1331 (NCT021664643).

MATERIALS/METHODS

This multicenter randomized, open-label phase 3 study enrolled patients 2-21 years (yrs) with previously untreated cHL: stages IIB + bulk, IIIB, IVA, IVB. Patients were randomized to 5 cycles of either ABVE-PC (doxorubicin, bleomycin, vincristine, etoposide, prednisone, cyclophosphamide) or the brentuximab vedotin (BV) containing regimen BV-AVE-PC given every 21 days. ISRT to 21 Gy was given to bulky mediastinal adenopathy and slow responding lesions (SRL) defined by 5-point score 4 or 5 on PET-CT after 2 cycles. ISRT could be delivered as 3D conformal XRT (3D), intensity modulated XRT (IMRT), or proton therapy (PT). Utilization of RT was compared by mode and by study enrollment midpoint among irradiated patients. Severe acute toxicity assessment included any incident grade 3 or higher toxicity during the ISRT period, except for neuropathy.

RESULTS

Among 587 eligible patients who were enrolled across 153 institutions between March 2015 and August 2019 with a median follow up of 43.1 months, the 3-yr PFS was 82.5% (90% CI, 78.3%-85.9%) with ABVE-PC and 92.5% (90% CI 89.5%-94.6%) with BV-AVE-PC (p = 0.0002). There was no difference in ISRT receipt or modality by study arm (p = 0.33). Among those who received RT 69.7% received it due to bulky mediastinal adenopathy, 6.6% due to SRL, and 23.7% for both. Overall, 317 (54.0%) patients received protocol RT of which 28.7% received 3D, 44.8% received IMRT, and 26.5% received PT. PT utilization increased over the course of the study from 21.5% among the first 50% of irradiated patients to 31.5% in the second half of irradiated patients (p = 0.045). The 3-yr progression-free survival rates overall by RT were comparable: PT (88.0%, 90% CI 80.6% - 92.7%%); XRT (87.1%, 90% CI 82.9%-90.4%) (p = 0.85). No difference in PFS was observed between 3D versus IMRT (p = 0.65). No differences were observed in severe acute toxicities (8.33% vs. 8.15%, p = 0.96) between PT and XRT.

CONCLUSION

Selective use of RT results in excellent outcomes for pediatric patients with high-risk HL and combination chemotherapy inclusive of the novel agent BV. Over the course of the study, PT utilization increased as an RT modality. Early results suggest that PT does not compromise disease control and has similar acute toxicity as XRT. Long term follow-up (>10 years) is needed to evaluate for secondary malignancies and cardiac toxicity among the different RT modalities.

Hepatocyte-derived exosomes deliver H2AFJ to hepatic stellate cells and promote liver fibrosis via the MAPK/STMN1 axis activation

Hepatic stellate cells (HSCs) activate and acquire proliferative features in response to liver injury. However, mechanisms involved in the activation of fibrotic HSCs remain uncharacterized. This study aims at elaborating the mechanistic basis by which exosomal H2AFJ derived from hepatocytes might affect the activation of HSCs and liver fibrosis. Bioinformatics analysis based on transcriptomic RNA-seq data was used to screen out the downstream regulatory genes and pathways of H2AFJ. Mouse hepatocytes AML-12 cells were stimulated with CCl₄ to mimic an in vitro microenvironment of liver fibrosis, from which exosomes were isolated. Next, HSCs were co-cultured with hepatocyte-derived exosomes followed by detection of HSC migration and invasion in the presence of manipulated H2AFJ and STMN1 expression and MAPK pathway inhibitor. It was found that H2AFJ was highly expressed in hepatocyte-derived exosomes after CCl₄ stimulation. Hepatocyte-derived exosomal H2AFJ promoted HSC migration and invasion. H2AFJ upregulated c-jun-mediated STMN1 by activating the MAPK signaling pathway. Furthermore, in vivo experiments verified that silencing of H2AFJ attenuated liver fibrosis in mice, while restoration of STMN1 negated its effect. Collectively, hepatocyte-derived exosomal H2AFJ aggravated liver fibrosis by activating the MAPK/STMN1 signaling pathway. This study provides a potential therapeutic target for alleviating liver fibrosis.

Construction of a Prognostic Signature of 10 Autophagy-Related lncRNAs in Gastric Cancer

Background

Autophagy plays a double-edged sword role in cancers. LncRNAs could regulate cancer initiation and development at various levels. However, the role of autophagy-related lncRNAs (ARlncs) in gastric cancer (GC) remains indistinct.

Methods

GC gene expression profile and clinical data were acquired from the Cancer Genome Atlas (TCGA). The prognostic signature composed of ARlncs was established via cox regression analysis. Kaplan–Meier (K-M) survival curve was adopted to show overall survival (OS). Independence and reliability of risk signature were visualized by cox regression analysis and ROC curve. A nomogram was constructed and the reliability was analyzed by ROC curve. Immune infiltrating cells and check points were also analyzed.

Results

A prognostic signature was constructed which stratified GC patients into high- and low-risk groups according to risk score calculated via the 10 ARlncs including LINC01094, AC068790.7, AC090772.1, AC005165.1, PVT1, LINC00106, AC026368.1, AC090912.3, AC013652.1, UICLM. Patients in high-risk group showed a poor prognosis (p<0.001). Cox regression analysis showed signature was an independent prognostic factor (p<0.001). Areas under curves (AUC) of ROC for risk signature for predicting OS outweighed age, gender, grade, T, M and N, which suggested the reliability of the signature. A nomogram was constructed with risk signature, T, M, N and age and its AUC of ROC for 1-, 3-, and 5-year was 0.700, 0.730, 0.757 respectively, which showed good reliability. Macrophage M2, T cell CD8+ and T cell CD4+ memory resting had greatest difference between the two risk groups according to CIBERSORE-ABS algorithm (p<0.001). CD274 (PD-L1), PDCD1 (PD-1) and PDCD1LG2 (PD-L2) were expressed higher in the high-risk group (p<0.05), which implied that immunotherapy may be a good choice for these patients.

Conclusion

The risk signature based on 10 ARlncs can serve as an efficacious prognostic predictor and guide the immunotherapies and precise treatment for GC patients.

Pocket-creation method versus conventional method of endoscopic submucosal dissection for superficial colorectal neoplasms: a meta-analysis

BACKGROUND AND AIMS

The pocket-creation method (PCM) is a newly developed strategy for colorectal endoscopic submucosal dissection (ESD). However, its superiority over the conventional method (CM) has not been established. The aim of this meta-analysis was to evaluate the efficacy and safety of PCM-ESD compared with CM-ESD for superficial colorectal neoplasms (SCNs).

METHODS

Literature searches were conducted using the Pubmed, Embase, and Cochrane Library databases, and a meta-analysis was performed. The primary outcome was the R0 resection rate, and the secondary outcomes were the en bloc resection rate, dissection speed, procedure time, and adverse event rate.

RESULTS

Five studies (2 randomized controlled trials and 3 retrospective studies) with 1481 patients were included in our meta-analysis. The pooled analysis showed that PCM-ESD achieved a higher R0 resection rate (93.5% vs 78.1%; odds ratio [OR], 3.4; 95% confidence interval [CI], 1.3-8.9; I² = 58%), a higher en bloc resection rate (99.8% vs 92.8%; OR, 9.9; 95% CI, 2.7-36.2; I² = 0), a shorter procedure time (minutes) (mean difference [MD], -11.5; 95% CI, -19.9 to -3.1; I² = 72%), a faster dissection speed (mm²/min) (MD, 3.6; 95% CI, 2.8-4.5; I² = 0), and a lower overall adverse event rate (4.4% vs 6.6%; OR, 0.6; 95% CI, 0.3-1.0; I² = 0) compared with CM-ESD.

CONCLUSIONS

This meta-analysis showed that PCM-ESD improves the efficacy and safety compared with CM-ESD for superficial colorectal neoplasms.

Long noncoding RNA SNHG14 accelerates cell proliferation, migration, invasion and suppresses apoptosis in colorectal cancer cells by targeting miR-944/KRAS axis through PI3K/AKT pathway

OBJECTIVE

Colorectal cancer (CRC) is a gastrointestinal tract cancer, which threatens the well-being of million of patients due to high metastasis. Recently, numerous studies have recognized nuclear RNA host gene 14 (SNHG14) as a remarkable oncogene in different cancers. However, the regulatory mechanism of SNHG14 in CRC development is mostly unclear.

PATIENTS AND METHODS

The expression of SNHG14, miR-944 and Kirsten rat sarcoma (KRAS) in tissues and cells was measured by quantitative Real-time polymerase chain reaction (qRT-PCR). Cell viability and apoptosis were evaluated by cell counting kit-8 (CCK-8) and flow cytometry assay, respectively. Cell migration and invasion were assessed using transwell assay. Protein expression of KRAS, AKT, phosphorylated AKT (p-AKT), phosphatidylinositol-3-kinase (PI3K) and phosphorylated PI3K (p-PI3K) was detected by Western blot. Animal models were constructed by subcutaneously injecting SW620 cells stably transfected with sh-SNHG14 and sh-NC. The interaction among SNHG14, miR-944 and KRAS was determined by luciferase reporter assay and RIP assay.

RESULTS

The expression of SNHG14 and KRAS was up-regulated whereas miR-944 was down-regulated in CRC tumors and cells compared with normal tissues and cells. In addition, SNHG14 silencing attenuated cell proliferation, migration and invasion, while accelerated apoptosis in CRC cells by suppressing PI3K/AKT pathway. Consistently, SNHG14 knockdown hindered tumor growth in vivo. MiR-944 was a target of SNHG14 and directly targeted KRAS. Moreover, miR-944 inhibitor abrogated silenced SNHG14-mediated inhibition on proliferation, migration and invasion, as well as promotion on apoptosis in CRC cells. Similarly, miR-944 regulated CRC cell progression by targeting KRAS through PI3K/AKT pathway.

CONCLUSIONS

SNHG14 contributed to cell proliferation, migration and invasion, while suppressed apoptosis in CRC cells by targeting miR-944/KRAS axis through PI3K/AKT pathway, representing novel biomarkers for CRC therapy.

[Clinical characteristics of 6 patients with blastic plasmacytoid dendritic cell neoplasm]

目的

探讨母细胞性浆细胞样树突细胞肿瘤（BPDCN）的临床特征、治疗和预后。

方法

回顾性分析2008年1月至2016年5月北京协和医院确诊的6例BPDCN患者的临床资料。

结果

6例患者起病时均有皮肤受累，常见表现包括骨髓受累（5例）、淋巴结肿大（4例）、脾大（4例）和肝大（3例）。皮肤外的结外器官受累包括乳腺、上颌窦、椎体和中枢神经系统各1例。肿瘤细胞特征性的免疫表型CD4、CD56、CD123均为阳性。治疗均采用急性淋巴细胞白血病样方案，4例达到完全缓解。中位随访9.5（7~37）个月，中位无进展生存期7个月，中位总生存期9个月。死亡3例，均在诊断后1年内死于原发病复发或进展。

结论

BPDCN侵袭性强，常以皮肤受累为首发症状，骨髓受累、淋巴结和肝脾大较为常见；特征性免疫标志包括CD4、CD56和CD123；目前缺乏有效、标准的治疗方案，预后不良。

Endoscopic mucosal resection with suction vs. endoscopic submucosal dissection for small rectal neuroendocrine tumors: a meta-analysis

OBJECTIVE

There are no guidelines or consensus on the optimal treatment measures for small rectal neuroendocrine tumors (NETs) at present. This meta-analysis was conducted to compare the efficacy and safety of endoscopic mucosal resection (EMR) with suction and endoscopic submucosal dissection (ESD) for the small rectal NETs.

METHODS

The literature searches were conducted using Pubmed and Embase databases, and then a meta-analysis was performed. The primary outcome was complete resection rate, and the secondary outcomes were complication rate, procedure time, and recurrence rate.

RESULTS

Fourteen studies with 823 patients were included in our meta-analysis. The overall complete resection rates in EMR with suction and ESD procedure were 93.65% (472/504) and 84.08% (243/289), respectively. The pooled analysis showed that EMR with suction could achieve a higher complete resection rate than ESD with significance (OR: 4.08, 95% CI: 2.42-6.88, p < .00001) when the outlier study was excluded, and procedure time was significantly shorter in the EMR with suction group than in the ESD group (SMD: -1.59, 95% CI: -2.27 to -0.90, p < .00001). Moreover, there was no significant difference in overall complication rate (OR: 0.56, 95% CI: 0.28-1.14, p = .11) and overall recurrence rate (OR: 0.76, 95% CI: 0.11-5.07, I²=48%) between EMR with suction and ESD group.

CONCLUSIONS

The present meta-analysis mostly based on retrospective studies show that EMR with suction is superior to ESD for small rectal NETs (≤10 mm) with higher complete resection rate, shorter procedure time, and similar overall complication rate and recurrence.

Endoscopic ultrasonography for staging depth of invasion in early gastric cancer: A meta-analysis

BACKGROUND AND AIM

Endoscopic ultrasonography (EUS) is a widely used imaging modality for detecting the depth of early gastric cancer (EGC) invasion. However, the studies pertaining to EUS for staging early gastric cancer have reported widely varied sensitivities and specificities. This study was conducted to estimate the overall diagnostic accuracy of EUS for staging the depth in EGCs.

METHODS

The literatures were identified by searching in PubMed, Embase, and Web of Knowledge databases. Two reviewers independently extracted the information from the literatures for constructing 2 × 2 table. A random-effect model or a fixed-effect model was used to estimate the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio. A summary receiver operating characteristic curve also was constructed. Meta-regression and subgroup analysis were used to explore the sources of heterogeneity.

RESULTS

The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of EUS for M staging were 76% (95% confidence interval [CI], 74-78%), 72% (95% CI, 69-75%), 3.67 (95% CI, 2.48-5.44), and 0.31 (95% CI, 0.24-0.40), respectively. For SM staging, these results were 62% (95% CI, 59-66%), 78% (95% CI, 76-80%), 2.99 (95% CI, 2.26-3.96), and 0.43 (95% CI, 0.32-0.57), respectively. For M/SM1 staging, they were 90% (95% CI, 88-92%), 67% (95% CI, 61-72%), 3.14 (95% CI, 2.08-4.73), and 0.12 (95% CI, 0.07-0.22), respectively. The area under the curve for mucosal, submucosal, and mucosal/minimal submucosal invasion staging were 0.85, 0.82, and 0.81, respectively.

CONCLUSIONS

Endoscopic ultrasonography only has a relatively low accuracy for staging the depth of invasion in EGCs. Accordingly, EUS may be not indispensable in the staging of EGCs.

Gemcitabine sensitizes pancreatic cancer cells to the CTLs antitumor response induced by BCG-stimulated dendritic cells via a Fas-dependent pathway

BACKGROUND/OBJECTIVES

There are increasing evidences suggesting that chemotherapeutic agents can enhance the cytotoxic T lymphocytes (CTLs) antitumor effect, but the precise mechanism is not fully explained. This study aims to investigate whether gemcitabine (GEM) can sensitize pancreatic cancer cells to the CTLs antitumor response, and explore the potential mechanism.

METHODS

Cell counting kit-8 assays (CCK-8) were performed to determine the tumor cell proliferation. Flow cytometric analysis was conducted to analyze maturation of DCs and the expression of Fas. An Annexin V FITC Apoptosis Detection Kit was performed to detect tumor cell apoptosis. CytoTox 96 Nonradioactive Cytotoxicity assays were used to determine T cell-mediated tumor cell lysis.

RESULTS

First, it was demonstrated that Bacillus Calmette Guérin (BCG) could be used to induce effective CTLs antitumor response. Then, GEM inhibited the growth of SW1990 cells, induced apoptosis and upregulated the Fas expression even at a low concentration. When antagonistic anti-Fas mAb ZB4 was preincubated with GEM-treated SW1990 cells, the lysis induced by CTLs was reduced. Moreover, agonistic anti-Fas mAb CH11 induced more apoptosis of GEM-treated SW1990 cells.

CONCLUSION

Our results show that GEM sensitizes pancreatic cancer cells to the CTLs antitumor response, and the sensitization is associated with upregulation of Fas on pancreatic cancer cells.

Triptolide induces apoptotic cell death of human cholangiocarcinoma cells through inhibition of myeloid cell leukemia-1

BACKGROUND

Cholangiocarcinoma (CCA), a devastating neoplasm, is highly resistant to current chemotherapies. CCA cells frequently overexpress the antiapoptotic protein myeloid cell leukemia-1(Mcl-1), which is responsible for its extraordinary ability to evade cell death. Triptolide, a bioactive ingredient extracted from Chinese medicinal plant, has been shown to inhibit cell proliferation and induce apoptosis in several cancers.

METHODS

CCK-8 assay was performed to detect cell survival rate in vitro. DAPI staining and Flow cytometry were used to analyze apoptosis. Western blot was performed to determine the expression levels of caspase-3, caspase-7, caspase-9, PARP, and Mcl-1. Quantitative real-time PCR and immunofluorescence were used to detect the expression levels of Mcl-1. The nude mice xenograft model was used to evaluate the antitumor effect of triptolide in vivo.

RESULTS

Triptolide reduced cell viability in cholangiocarcinoma cell lines in a dose- and time-dependent manner, with IC50 values of 12.6 ± 0.6 nM, 20.5 ± 4.2 nM, and 18.5 ± 0.7 nM at 48 h for HuCCT1, QBC939, and FRH0201 respectively. Triptolide induced apoptosis in CCA cell lines in part through mitochondrial pathway. Using quantitative real-time PCR, western blot and immunofluorescence, we have shown that triptolide downregulates Mcl-1 mRNA and protein levels. Furthermore, triptolide inhibited the CCA growth in vivo.

CONCLUSIONS

Triptolide has profound antitumor effect on CCA, probably by inducing apoptosis through inhibition of Mcl-1. Triptolide would be a promising therapeutic agent for CCA.

Serum lipid abnormalities are not associated with apoB 3' VNTR polymorphism in nephrotic children

Apolipoprotein B (apoB) gene 3' variable number of tandem repeat (VNTR) is highly variable, and therefore can be an informative marker for associative analysis of lipid metabolism. This is the first report focusing on a possible association of apoB VNTR polymorphism with nephrotic hyperlipidemia. Genomic DNA was extracted from 500 children with primary nephrotic syndrome (PNS) and 500 healthy controls. The apoB genotype was determined by PCR analysis. Allele size distribution followed a unimodal curve, with the main peak at the hypervariable element 35 (HVE35); the most prevalent genotype was HVE35/35 in both control and PNS children. The genotype and allele distributions of apoB variants in PNS children were not significantly different from controls. There was significant variation in serum lipid profiles among different genotypes in control children. Individuals with the long (L) allele exhibited significantly higher total cholesterol, low-density lipoprotein cholesterol (LDL-C) and apoB levels than those with the medium (M) or short (S) allele; consequently, M/L carriers had significantly higher total cholesterol, LDL-C and apoB concentrations than did S/S, S/M, S/L, or M/M carriers. However, in PNS children, no significant differences in serum lipid levels were observed among individuals with different genotypes and alleles of apoB 3' VNTR. We conclude that hyperlipidemia in nephrotic children is not associated with apoB 3' VNTR polymorphism.

Diagnostic value of EUS elastography in differentiation of benign and malignant solid pancreatic masses: a meta-analysis

BACKGROUND/AIMS

EUS elastography is a novel technique that can be used for distinguishing benign from malignant lymph nodes and focal pancreatic masses. However, the studies pertaining to EUS elastography for differential diagnosis of solid pancreatic masses have reported widely varied sensitivities and specificities. A meta-analysis of all relevant articles was performed to estimate the overall diagnostic accuracy of EUS elastography for differentiating benign and malignant solid pancreatic masses.

METHODS

The literatures were identified by searching in PubMed and Embase databases. Two reviewers independently extracted the information from the literatures for constructing 2 × 2 table. A random-effect model or a fixed-effect model was used to estimate the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio. A summary receiver operating characteristic curve (SROC) also was constructed. Meta-regression and subgroup analysis were used to explore the sources of heterogeneity.

RESULTS

13 studies including a total of 1042 patients with solid pancreatic masses were selected for meta-analysis. The pooled sensitivity and specificity of EUS elastography for differentiating benign and malignant solid pancreatic masses were 95% (95% confidence interval [CI], 93%-96%), 69% (95% CI, 63%-75%), respectively. The area under SROC (AUC) was 0.8695. Two significant variables were associated with heterogeneity: color pattern and blinding.

CONCLUSION

As a less invasive modality, EUS elastography is a promising method for differentiating benign and malignant solid pancreatic masses with a high sensitivity, and it can prove to be a valuable supplement to EUS-FNA.

Polymer light-emitting electrochemical cells

A device configuration for light emission from electroactive polymers is described. In these light-emitting electrochemical cells, a p-n junction diode is created in situ through simultaneous p-type and n-type electrochemical doping on opposite sides of a thin film of conjugated polymer that contains added electrolyte to provide the necessary counterions for doping. Light-emitting devices based on conjugated polymers have been fabricated that operate by the proposed electrochemical oxidation-reduction mechanism. Blue, green, and orange emission have been obtained with turn-on voltages close to the band gap of the emissive material.

Glutamate receptor activation is involved in 5-HT2 agonist-induced Arc gene expression in the rat cortex

Brain 5-HT regulates the expression of gene transcription factor as well as novel effector immediate early genes (IEGs). The 5-HT regulation of the gene transcription factor IEG, c-fos, involves activation of 5-HT2A and ionotropic glutamate receptors. Here, we investigate whether these receptors are also involved in the regulation of the effector IEG, Arc. In rats, the 5-HT2 agonist DOI induced a marked increase in expression of Arc mRNA in a variety of cortical regions. This effect was blocked by the selective 5-HT2A receptor antagonist, MDL 100,907, but not the 5-HT(2B/2C) receptor antagonist, SB206553. The AMPA receptor antagonist GYKI 52466 also attenuated DOI-induced Arc mRNA expression, as did the NMDA receptor antagonist MK801 in some regions. Immunofluorescence studies showed that DOI increased Arc-immunoreactivity in cortical cells that expressed AMPA and NMDA receptor subunits but not the 5-HT2A receptor. Finally, DOI-induced Arc-immunoreactivity in cortical cells was extensively co-localised with c-fos-immunoreactivity. These results suggest that, as with c-fos expression, ionotropic glutamate receptors (AMPA and NMDA) are involved in 5-HT2A receptor-induced Arc expression. This finding, together with evidence of extensive Arc and c-fos co-localisation, suggests that 5-HT2A receptor activation may induce the expression of both effector and transcription factor IEGs via common molecular and cellular substrates.

Antidepressant drug treatment induces Arc gene expression in the rat brain

The mechanism underlying the therapeutic effect of antidepressants is not known but neuroadaptive processes akin to long-term potentiation have been postulated. Arc (Activity-regulated, cytoskeletal-associated protein) is an effector immediate early gene implicated in LTP and other forms of neuroplasticity. Recent data show that Arc expression is regulated by brain 5-hydroxytryptamine neurones, a target of many antidepressants. Here in situ hybridisation and immunohistochemistry were used to examine whether Arc expression in rat brain is altered by antidepressant drug treatment. Repeated administration of the monoamine reuptake inhibitors paroxetine, venlafaxine or desipramine induced region-specific increases in Arc mRNA. These increases were greatest in regions of the cortex (frontal and parietal cortex) and hippocampus (CA1 layer) and absent in the caudate putamen. Repeated treatment with the monoamine oxidase inhibitor, tranylcypromine, increased Arc mRNA in a similar fashion to the monoamine reuptake inhibitors. The antidepressant drugs also increased the number of Arc-immunoreactive cells in the parietal cortex. Acute antidepressant injection, and repeated administration of the antipsychotic drug chlorpromazine, produced either limited or no changes in Arc mRNA. The data suggest that chronic treatment with antidepressant drugs induces Arc gene expression in specific regions across the rat forebrain. Up-regulation of Arc expression may be part of the process by which antidepressant drugs achieve long-term changes in synaptic function in the brain.

Bi-phasic change in BDNF gene expression following antidepressant drug treatment

The gene for brain derived neurotrophic factor (BDNF) has recently received attention in relation to the therapeutic action of antidepressant treatment. This study aimed to clarify the influence of post drug interval on the effect of acute and repeated treatment with antidepressant drugs on BDNF gene expression in the rat brain. It was found that repeated administration of either the monoamine oxidase inhibitor tranylcypromine (TCP) or 5-hydroxytryptamine (5-HT) re-uptake inhibitors (fluoxetine, paroxetine and sertraline), evoke a bi-phasic and time-dependent effect on BDNF gene expression in the rat hippocampus (especially dentate gyrus). A down-regulation of the BDNF gene was detected at 4 h (TCP and fluoxetine) and an up-regulation at 24 h (TCP, paroxetine, fluoxetine, sertraline) after the last of twice daily injections for 14 days. After a single injection the down-regulation was detected at 4 h (TCP, fluoxetine, paroxetine and sertraline) but BDNF mRNA levels were not altered at 24 h post drug (TCP, fluoxetine and paroxetine). Administration of inhibitors of noradrenaline re-uptake (desipramine and maprotiline) or the atypical antidepressant mianserin had no effect on BDNF mRNA levels at either single (4 h post drug, desipramine) or repeated (24 h post drug, desipramine, maprotiline, mianserin) treatment. The gene expression for NT-3, which is distributed in a high density in the dentate gyrus, was not affected by single or repeated injections of antidepressant drugs (TCP, fluoxetine, paroxetine, sertraline, desipramine, maprotiline or mianserin) at 4 or 24 h post drug. In conclusion, these data show that the effect of antidepressant drugs on BDNF gene expression may be more complex and less widespread across treatments than previously thought. Thus, in this study drugs interacting with the central 5-HT system altered BDNF expression but the effect was bi-phasic over the 24 h post drug period.

Effect of different 5-HT1A receptor antagonists in combination with paroxetine on expression of the immediate-early gene Arc in rat brain

Selective 5-HT(1A) receptor antagonists enhance the effect of selective serotonin reuptake inhibitors (SSRIs) on presynaptic 5-HT function, and have potential as antidepressant augmentation therapies. The present study tested the effect of different selective 5-HT(1A) receptor antagonists (WAY 100635, NAD-299, p-MPPI and LY 426965) in combination with a SSRI (paroxetine), on postsynaptic 5-HT function measured by increased expression of the immediate early gene, Arc. Paroxetine (5 mg/kg s.c.) combined with WAY 100635 (0.3 mg/kg s.c.) increased Arc mRNA in frontal, parietal and piriform cortices, and caudate putamen. Paroxetine (5 mg/kg s.c.) plus NAD-299 (1 or 5 mg/kg s.c.) had a similar effect. None of these drugs increased Arc mRNA when administered alone. Paroxetine (5 mg/kg s.c.) plus p-MPPI (8.5 mg/kg s.c.) also increased Arc mRNA but p-MPPI itself elevated Arc mRNA in many regions. Whilst LY 426965 (3 or 10 mg/kg s.c.) had no effect alone, when combined with paroxetine (5 mg/kg s.c.), the drug increased Arc mRNA in caudate putamen but not cortical regions.In conclusion, this study demonstrates that four 5-HT(1A) receptor antagonists augment the effect of an SSRI on Arc mRNA expression, which is suggestive of increased postsynaptic 5-HT function. However, the data reveal certain differences in the 5-HT(1A) receptor antagonists not recognised in models of presynaptic 5-HT function.

Serotonergic cells of the rat raphe nuclei express mRNA of tyrosine kinase B (trkB), the high-affinity receptor for brain derived neurotrophic factor (BDNF)

Here we have studied the distribution of mRNA for tyrosine kinase B (trkB), the high-affinity receptor for brain-derived neurotrophic factor (BDNF) amongst serotonergic cell bodies of the raphe nuclei and their ascending projections into the dorsal hippocampus in the rat brain. Previous studies have shown that BDNF has got trophic action on serotonergic neurons. In the present study, we provide evidence that serotonergic neurons express mRNA for the functional receptor of BDNF, trkB. Intracerebro-ventricular (i.c.v.) injection of the 5-HT-specific neurotoxin, 5,7-dihydroxytryptamine, which lesions serotonergic cell bodies in the raphe nuclei as well as their ascending projections into the dorsal hippocampus, caused a dramatic loss of trkB mRNA from serotonergic cell bodies of the dorsal raphe nucleus. In contrast, there was no change in the abundance of trkB mRNA within the dorsal hippocampus. These findings provide direct evidence for the expression of trkB mRNA by serotonergic neurons and suggest distinct mechanisms of action of BDNF upon serotonergic neurons at the levels of their cell bodies and terminal projection sites.

Influence of thyroid hormone on 5-HT(1A) and 5-HT(2A) receptor-mediated regulation of hippocampal BDNF mRNA expression

The aim of the present study was to determine the influence of thyroid hormone, T3, on the regulation of hippocampal BDNF expression by 5-HT receptor agonists. Chronic T3 administration prior to treatment with the 5-HT(1A) agonist, 8-OH-DPAT, significantly decreased BDNF mRNA in the dentate gyrus region of the hippocampus. Administration of 8-OH-DPAT did not alter hippocampal BDNF mRNA expression in naive, euthyroid rats. Pretreatment with the 5-HT(1A) antagonist, WAY 100635, completely blocked the 8-OH-DPAT-induced down-regulation of BDNF mRNA in chronic T3-treated rats. Acute T3 administration prior to 8-OH-DPAT treatment led to a small, but significant, decrease in hippocampal dentate gyrus BDNF mRNA. Acute or chronic administration of T3 did not alter the decrease in hippocampal BDNF mRNA induced by the 5-HT(2A/2C) receptor agonist, DOI. The influence of 8-OH-DPAT and DOI on hippocampal BDNF mRNA was also unaltered in rats rendered hypothyroid by propylthiouracil administration. Chronic T3 treatment or hypothyroidism did not influence the basal expression of hippocampal BDNF mRNA. The affinity and density of 5-HT(1A) receptors, and the hippocampal expression of 5-HT(1A) mRNA were also not influenced by chronic T3 treatment. The results of this study clearly demonstrate a powerful interaction between thyroid hormone and the 5-HT(1A) receptor in the regulation of hippocampal BDNF expression. Crosstalk between signal transduction cascades influenced by T3 and 5-HT(1A) receptors may mediate the synergistic effects of these systems on hippocampal BDNF expression.

Electroconvulsive shock increases tachykinin NK(1) receptors, but not the encoding mRNA, in rat cortex

Recent studies have suggested that the substance P (tachykinin NK(1)) receptor may be a pharmacological target for the treatment of mood disorders. Here, the effects of electroconvulsive shock on tachykinin NK(1) receptor gene expression in the rat brain was investigated. Rats received either a single electroconvulsive shock or five shocks on alternate days. Quantitative autoradiography with [(125)I]Bolton Hunter-substance P, and in situ hybridisation histochemistry, were used to measure tachykinin NK(1) receptor-binding site densities and mRNA abundance, respectively. Densities of tachykinin NK(1) receptor-binding sites were significantly increased in the cerebral cortex following repeated electroconvulsive shock compared to sham treated animals. Densities remained unchanged in the hippocampus, striatum and amygdala. Neither single nor repeated electroconvulsive shock altered tachykinin NK(1) receptor mRNA in the brain regions examined. Hence, repeated electroconvulsive shock increases tachykinin NK(1) receptors in the rat brain in a regionally specific way. Upregulation of receptor-binding sites without a change in mRNA indicates that translational or post-translational mechanisms underlie this process.

Repeated electroconvulsive shock promotes the sprouting of serotonergic axons in the lesioned rat hippocampus

This study reports the effect of repeated electroconvulsive shock on the sprouting of 5-hydroxytryptamine neurons in the partly lesioned rat dorsal hippocampus. We have adopted a 5-hydroxytryptamine homotypic collateral sprouting model to examine whether electroconvulsive shock administration altered the rate of 5-hydroxytryptamine axonal reinnervation of the dorsal hippocampus. The 5-hydroxytryptamine innervation of hippocampus originates from the median raphe via the cingulum bundle and the fimbria-fornix. Lesioning of the cingulum bundle has previously been shown to cause sprouting of intact 5-hydroxytryptamine afferents originating from the unharmed fimbria-fornix. Rats were unilaterally injected with the 5-hydroxytryptamine neurotoxin, 5,7-dihydroxytryptamine, into the right cingulum bundle and 5-hydroxytryptamine immunoreactivity in the dorsal hippocampus was investigated 1, 3, 6 and 12weeks after the injection. The lowest level of 5-hydroxytryptamine-immunoreactivity in the hippocampus was detected at three weeks after the lesion. At six weeks, 5-hydroxytryptamine immunoreactive fibres started to reappear, and at 12weeks the level of 5-hydroxytryptamine immunoreactivity was similar to that observed on the unlesioned side. Based on this time-course, six weeks was chosen as the time-point to investigate the action of a course of repeated electroconvulsive shock administrations. Repeated electroconvulsive shock (five shocks over 10days) doubled the number of sprouting 5-hydroxytryptamine-immunoreactive fibres and significantly increased levels of the 5-hydroxytryptamine metabolite, 5-hydroxyindoleacetic acid. The present data provide the first direct evidence that electroconvulsive shock enhances 5-hydroxytryptamine axon sprouting in the partly lesioned hippocampus. This is an effect which may contribute to the therapeutic effect of electroconvulsive therapy in major depression.

High-speed electrically actuated elastomers with strain greater than 100%

Electrical actuators were made from films of dielectric elastomers (such as silicones) coated on both sides with compliant electrode material. When voltage was applied, the resulting electrostatic forces compressed the film in thickness and expanded it in area, producing strains up to 30 to 40%. It is now shown that prestraining the film further improves the performance of these devices. Actuated strains up to 117% were demonstrated with silicone elastomers, and up to 215% with acrylic elastomers using biaxially and uniaxially prestrained films. The strain, pressure, and response time of silicone exceeded those of natural muscle; specific energy densities greatly exceeded those of other field-actuated materials. Because the actuation mechanism is faster than in other high-strain electroactive polymers, this technology may be suitable for diverse applications.

Serotonergic regulation of mRNA expression of Arc, an immediate early gene selectively localized at neuronal dendrites

Arc (activity regulated, cytoskeleton associated protein) is an effector immediate early gene that is selectively localized in the neuronal dendrites. Elevation of brain 5-HT by the combined administration of the monoamine oxidase inhibitor, tranylcypromine (TCP, 5 mg/kg, i.p.), and the 5-HT precursor L-tryptophan (L-TP, 100 mg/kg, i.p.), increased Arc mRNA abundance in the cingulate, orbital, frontal and parietal cortices as well as in the striatum but a reduction was observed in the CA1 region of the hippocampus. The 5-HT releasing agent p-chloroamphetamine (PCA, 5 mg/kg, s.c.) also increased Arc mRNA in the cortical and striatal areas. Depleting brain 5-HT with the tryptophan hydroxylase inhibitor, p-chlorophenylalanine (pCPA, 300 mg/kg, i.p. for two days), on the other hand, significantly attenuated the increase in Arc mRNA induced by tranylcypromine and L-tryptophan (TCP/L-TP). Pretreatment with the 5-HT2 receptor antagonist ketanserin (2 mg/kg, i.p.) significantly attenuated the effect of TCP/L-TP in the cortex but only partially in striatum and did not affect the reduction in the CA1 region. The 5-HT2 agonist DOI (0.2, 1 and 2 mg/kg, i.p.) dose-dependently increased Arc mRNA abundance in cortical areas with a pattern similar to that of TCP/L-TP and PCA. DOI, however, had much weaker effects on Arc mRNA in the striatum and did not have any significant effect in the CA1, CA3 and the dentate gyms (DG) of the hippocampus. Pretreatment with ketanserin completely blocked the effect of DOI on Arc expression. These data suggest that Arc mRNA expression can be induced in the cortex by increases in extracellular 5-HT and that 5-HT2 receptors play a major part in mediating such effects. Additional 5-HT receptors as well as other neurotransmitters may also be involved, particularly in the striatum and in CA1 subfield of the hippocampus. Overall, our data suggest that expression of Arc mRNA is highly responsive to changes in brain 5-HT functions, and may provide a sensitive marker of postsynaptic 5-HT2(2A and 2C) receptor functions.

Manipulations of brain 5-HT levels affect gene expression for BDNF in rat brain

The aim of the present study was to investigate whether changes in brain 5-HT concentrations affect the expression of BDNF mRNA in rat brain. Brain 5-HT concentration in the rat was elevated by combined treatment with tranylcypromine and L-tryptophan, tranylcypromine alone, by a single dose of the 5-HT releasing agent p-chloroamphetamine (PCA) or by the selective 5-HT reuptake inhibitor paroxetine. 5-HT was depleted by either multiple p-chlorophenylalanine (pCPA) or PCA injections. The extent of 5-HT depletion following pCPA or PCA was monitored using 5-HT immunocytochemistry. BDNF mRNA abundance in treated rats and the corresponding vehicle injected control rats was studied by in situ hybridization histochemistry (ISHH). Two hours after the combined administration of tranylcypromine and L-tryptophan BDNF mRNA abundance in the dentate gyrus was significantly decreased but increased in the frontal cortex. Tranylcypromine alone or a single injection of PCA had similar effects on BDNF mRNA expression to the combination of tranylcypromine and L-tryptophan, i.e. they caused significant reductions of BDNF mRNA expression in dentate gyrus and increased it in frontal cortex. Paroxetine also reduced BDNF mRNA in DG but was without effect in frontal cortex. Multiple injections of both pCPA or PCA resulted in marked reductions of 5-HT immunoreactive axons in the hippocampus, pCPA being more effective. Both drugs significantly increased BDNF mRNA abundances in the dentate gyrus. Multiple PCA injections also increased BDNF mRNA expression in parietal cortex, while pCPA induced 5-HT depletion was ineffective. These results suggests that 5-HT modulates BDNF mRNA levels in rat brain.

Alteration in expression of G-protein-activated inward rectifier K+-channel subunits GIRK1 and GIRK2 in the rat brain following electroconvulsive shock

G-protein-activated inward rectifier potassium channels are coupled to a number of neurotransmitter receptors, including some monoamine receptors. In the present study we have investigated the effect of electroconvulsive shock on gene expression of the G-protein-activated inward rectifier potassium channel subunits G-protein-coupled inward rectifier K+-channel (GIRK1) and GIRK2 in the rat brain using in situ hybridization and immunocytochemistry. Acute electroconvulsive shock (a single shock) increased GIRK2 expression while causing a transient reduction of the messenger RNA abundance of GIRK1 in granule cells of the dentate gyrus. Chronic electroconvulsive shock (five shocks over 10 days) caused a larger increase in GIRK2 messenger RNA abundance, which was accompanied by an increase in GIRK2 immunoreactivity in the molecular layer of the dentate gyrus. Unlike for acute electroconvulsive shock, GIRK1 messenger RNA abundance in the dentate gyrus was significantly increased after chronic electroconvulsive shock. No significant alterations in GIRK1 and GIRK2 messenger RNA abundance were detected in the other brain regions studied, including the CA1 and CA3 subfields of the hippocampus, the frontal-parietal cortex and piriform cortex. The neuroanatomically specific changes in expression of the potassium channel subunits may directly influence neuronal excitability as well as the functions of G-protein-coupled neurotransmitter receptors.

[Dynamic changes of nitric oxide and biochemistry in rats with intrahepatic cholestasis]

OBJECTIVE

To investigate the correlation between nitric oxide and biochemical changes of intrahepatic cholestasis.

METHODS

Studies were made on endogenous NO, biochemical changes of cholestasis, liver mitochondrial function and renal excretion in a rat model at different time points after ANIT administration.

RESULTS

In acute reactive phase, serum bilirubin, ALT, AKP, and bile acids significantly increased, accompanied by enhanced plasma NO and renal excretion. Liver NO increased and mitochondrial SDH activity decreased for 2-6 days after ANIT. There was a high negative correlation between liver NO and mitochondrial SDH activity (r = -0.92).

CONCLUSION

These results show that higher liver NO may be an important mediator of intrahepatic cholestasis. However, plasma NO increase may play a role in rapidly decreasing serum bilirubin and restoring bile acids, ALT, and AKP to control levels by mediating enhanced renal excretion.

Effect of antidepressant drugs on dopamine D1 and D2 receptor expression and dopamine release in the nucleus accumbens of the rat

This study examined the effect of repeated treatment with the antidepressant drugs, fluoxetine, desipramine and tranylcypromine, on dopamine receptor expression (mRNA and binding site density) in sub-regions of the nucleus accumbens and striatum of the rat. The effect of these treatments on extracellular levels of dopamine in the nucleus accumbens was also measured. Experiments using in situ hybridisation showed that the antidepressants caused a region-specific increase in D2 mRNA, this effect being most prominent in the nucleus accumbens shell. In contrast, none of the treatments increased D1 mRNA in any of the regions examined. Measurement of D2-like binding by receptor autoradiography, using the ligand [3H]YM-09151-2, revealed that both fluoxetine and desipramine increased D2-like binding in the nucleus accumbens shell; fluoxetine had a similar effect in the nucleus accumbens core. Tranylcypromine, however, had no effect on D2-like binding in the nucleus accumbens but decreased binding in the striatum. In micro-dialysis experiments, our data showed that levels of extracellular dopamine in the nucleus accumbens were not altered in rats treated with either fluoxetine or desipramine, but increased by tranylcypromine. From our findings, we propose that the antidepressant drugs tested enhance dopamine function in the nucleus accumbens through either increased expression of post-synaptic D2 receptors (fluoxetine and desipramine) or increased dopamine release (tranylcypromine).

Differential effects of electroconvulsive shock on the glutamate receptor mRNAs for NR2A, NR2B and mGluR5b

We have studied the effects of single and repeated electroconvulsive shock (ECS) treatment on the mRNA levels of several glutamate receptors in the dentate gyrus and CA1 regions of the rat brain. In the dentate gyrus, such treatment elevated the mRNAs for the NMDA subunits NR2A and NR2B, but it reduced the mRNA for the metabotropic glutamate receptor mGlu5b. With the exception of NR2A, this effect was specific to the dentate gyrus. The changes in NR2B mRNA lasted the longest, but all changes had returned to control values after 48 h. The possible significance of such changes to the antidepressant effect of ECT is discussed.

Repeated electroconvulsive shock extends the duration of enhanced gene expression for BDNF in rat brain compared with a single administration

Brain-derived neurotrophic factor (BDNF) is known to modulate synaptic function as well as to promote neuronal growth in the adult brain. The aim of the present study was to compare the duration of electroconvulsive shock (ECS)-induced BDNF gene expression following a single shock (acute ECS) to the more clinically relevant situation, where repeated shocks (chronic ECS) are administered. For this purpose, we have used quantitative in situ hybridisation with a 35S-labelled oligonucleotide probe complementary to mRNAs encoding genes for all forms of BDNF. The results confirm previous studies that the administration of ECS increases BDNF mRNA abundance in parts of rat brain with particularly marked changes in the granule cell layer of the dentate gyrus. We also for the first time show the long lasting nature of the increase in BDNF mRNA abundance measured after chronic ECS, i.e., significant increases in BDNF mRNA persisted up to 48 h after the last shock. Acute ECS at 6 h after the shock produced a slightly more pronounced effect on BDNF mRNA abundance than chronic ECS 6 h after the last shock. However, this change was not detectable already 24 h after a single ECS. These results indicate that repeated ECS induces adaptive changes in BDNF mRNA expression.

Changes in mRNA abundance of microtubule-associated proteins in the rat brain following electroconvulsive shock

Microtubule-associated proteins (MAPs) are involved in the maintenance of mature neuronal morphology, neurite outgrowth and neuronal plasticity. Alteration in MAP expression may underlie neuronal structural changes in response to seizure activity. The aim of the present study was to investigate whether electroconvulsive shock (ECS), an animal model of electroconvulsive therapy (ECT) in clinical treatment of depression, affected gene expression of MAPs in the rat brain. Using in situ hybridization, we studied the expression of encoding mRNA for MAPs in the brains of rats treated with ECS 5 times over 10 days. The abundance of mRNA encoding microtubule-associated protein 2 (MAP2), a dendritic MAP, was significantly increased (142% compared with controls) in the dentate gyrus 6 and 24 h after the last shock, and had returned to baseline levels within 48 h. These changes were confined to the dentate gyrus no significant changes were observed in CA1 and CA3 of the hippocampus. The increase in MAP2 expression was accompanied by an increase in MAP2 immunoreactivity in the molecular layer of the dentate gyrus. The abundance of mRNA encoding for tau, an axon-specific MAP, and MAP1B, an embryonic MAP, was unaffected by ECS. These data demonstrate that ECS specifically altered the mRNA and protein expression of MAP2 but had no effect on tau or MAP1B, and suggest that changes in MAP2 expression may be related to morphological changes in the dentate gyrus, particularly in the dendrites.

Differential effects of acute and chronic electroconvulsive shock on the abundance of messenger RNAs for voltage-dependent potassium channel subunits in the rat brain

The effect of acute and chronic electroconvulsive shock on the abundance of messenger RNAs encoding voltage-dependent potassium channel subunits in the rat brain was determined by in situ hybridization histochemistry with [35S]dATP-labelled oligonucleotides at 6 h, 24 h and three weeks following the last shock. The messenger RNA abundance of two voltage-dependent potassium channel subunits, Kv1.2 and Kv4.2, was altered by electroconvulsive shock but in different ways. In acute electroconvulsive shock experiments, Kv1.2 and Kv4.2 messenger RNA abundance in the dentate gyrus were reduced 6 h following the shock and returned to control levels after 24 h. In chronic electroconvulsive shock-treated rats, Kv1.2 messenger RNA abundance showed similar changes to those in acute electroconvulsive shock: it was reduced 6 h after the last shock and had recovered after 24 h. Kv4.2 messenger RNA abundance in chronic electroconvulsive shock-treated rats, however, showed adaptive changes: 6 h after the last shock there were no changes in its abundance while 24 h after the last shock there was a significant increase in the dentate gyrus. The changes in Kv1.2 and Kv4.2 messenger RNA abundance following electroconvulsive shock were only observed in the dentate gyrus and not in cornu ammonis 1 and cornu ammonis 3 of hippocampus or frontal-parietal cortex. Two other potassium channel subunits, Kv1.1 and Kv1.4, were not affected by either acute or chronic electroconvulsive shock. These findings indicate that acute and chronic electroconvulsive shock affect the gene expression of voltage-dependent potassium channel subunits with specificities for channel type, anatomical region and timing.

The nicotinic receptor agonists (-)-nicotine and isoarecolone differ in their effects on dopamine release in the nucleus accumbens

This study compared the effect of the nicotinic receptor agonists, (-)-nicotine and isoarecolone, on the mesolimbic dopamine system of the rat using in vivo microdialysis. Previous studies showed that (-)-nicotine but not isoarecolone produced a locomotor activating effect, and that this was probably mediated by increased concentrations of dopamine in the nucleus accumbens. Nicotine (0.4 mg/kg s.c.) significantly increased extracellular concentrations of dopamine and of dihydroxyphenylacetic acid (DOPAC) by 75-80% in nucleus accumbens of rats. Isoarecolone (3.2-32 mg/kg s.c.) had no significant effect on either dopamine or DOPAC levels in this brain region and neither drug affected extracellular levels of 5-hydroxy indole acetic acid. Both nicotine and isoarecolone induced head-bobbing behaviour. Pretreatment with ketanserin reduced nicotine-induced head-bobbing suggesting a serotonergic mechanism. In conclusion, the absence of locomotor activation after administration of isoarecolone may be related to its failure to activate the mesolimbic dopamine system.