Building consensus for the medical management of children with moderate and severe acute spinal cord injury: a modified Delphi study.

OBJECTIVE: The focus of this modified Delphi study was to investigate and build consensus regarding the medical management of children with moderate and severe acute spinal cord injury (SCI) during their initial inpatient hospitalization. This impetus for the study was based on the AANS/CNS guidelines for pediatric SCI published in 2013, which indicated that there was no consensus provided in the literature describing the medical management of pediatric patients with SCIs. METHODS: An international, multidisciplinary group of 19 physicians, including pediatric neurosurgeons, orthopedic surgeons, and intensivists, were asked to participate. The authors chose to include both complete and incomplete injuries with traumatic as well as iatrogenic etiologies (e.g., spinal deformity surgery, spinal traction, intradural spinal surgery, etc.) due to the overall low incidence of pediatric SCI, potentially similar pathophysiology, and scarce literature exploring whether different etiologies of SCI should be managed differently. An initial survey of current practices was administered, and based on the responses, a follow-up survey of potential consensus statements was distributed. Consensus was defined as ≥ 80% of participants reaching agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree). A final meeting was held virtually to generate final consensus statements. RESULTS: Following the final Delphi round, 35 statements reached consensus after modification and consolidation of previous statements. Statements were categorized into the following eight sections: inpatient care unit, spinal immobilization, pharmacological management, cardiopulmonary management, venous thromboembolism prophylaxis, genitourinary management, gastrointestinal/nutritional management, and pressure ulcer prophylaxis. All participants stated that they would be willing or somewhat willing to change their practices based on consensus guidelines. CONCLUSIONS: General management strategies were similar for both iatrogenic (e.g., spinal deformity, traction, etc.) and traumatic SCIs. Steroids were recommended only for injury after intradural surgery, not after acute traumatic or iatrogenic extradural surgery. Consensus was reached that mean arterial pressure ranges are preferred for blood pressure targets following SCI, with goals between 80 and 90 mm Hg for children at least 6 years of age. Further multicenter study of steroid use following acute neuromonitoring changes was recommended.

Developing consensus for the management of pediatric cervical spine disorders and stabilization: a modified Delphi study.

OBJECTIVE: Cervical spine disorders in children are relatively uncommon; therefore, paradigms for surgical and nonsurgical clinical management are not well established. The purpose of this study was to bring together an international, multidisciplinary group of pediatric cervical spine experts to build consensus via a modified Delphi approach regarding the clinical management of children with cervical spine disorders and those undergoing cervical spine stabilization surgery. METHODS: A modified Delphi method was used to identify consensus statements for the management of children with cervical spine disorders requiring stabilization. A survey of current practices, supplemented by a literature review, was electronically distributed to 17 neurosurgeons and orthopedic surgeons experienced with the clinical management of pediatric cervical spine disorders. Subsequently, 52 summary statements were formulated and distributed to the group. Statements that reached near consensus or that were of particular interest were then discussed during an in-person meeting to attain further consensus. Consensus was defined as ≥ 80% agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree). RESULTS: Forty-five consensus-driven statements were identified, with all participants willing to incorporate them into their practice. For children with cervical spine disorders and/or stabilization, consensus statements were divided into the following categories: A) preoperative planning (12 statements); B) radiographic thresholds of instability (4); C) intraoperative/perioperative management (15); D) postoperative care (11); and E) nonoperative management (3). Several important statements reaching consensus included the following recommendations: 1) to obtain pre-positioning baseline signals with intraoperative neuromonitoring; 2) to use rigid instrumentation when technically feasible; 3) to provide postoperative external immobilization for 6-12 weeks with a rigid cervical collar rather than halo vest immobilization; and 4) to continue clinical postoperative follow-up at least until anatomical cervical spine maturity was reached. In addition, preoperative radiographic thresholds for instability that reached consensus included the following: 1) translational motion ≥ 5 mm at C1-2 (excluding patients with Down syndrome) or ≥ 4 mm in the subaxial spine; 2) dynamic angulation in the subaxial spine ≥ 10°; and 3) abnormal motion and T2 signal change on MRI seen at the same level. CONCLUSIONS: In this study, the authors have demonstrated that a multidisciplinary, international group of pediatric cervical spine experts was able to reach consensus on 45 statements regarding the management of pediatric cervical spine disorders and stabilization. Further study is required to determine if implementation of these practices can lead to reduced complications and improved outcomes for children.

High prevalence of gram-negative and multiorganism surgical site infections after pediatric complex tethered spinal cord surgery: a multicenter study.

OBJECTIVE: Complex tethered spinal cord (cTSC) release in children is often complicated by surgical site infection (SSI). Children undergoing this surgery share many similarities with patients undergoing correction for neuromuscular scoliosis, where high rates of gram-negative and polymicrobial infections have been reported. Similar organisms isolated from SSIs after cTSC release were recently demonstrated in a single-center pilot study. The purpose of this investigation was to determine if these findings are reproducible across a larger, multicenter study. METHODS: A multicenter, retrospective chart review including 7 centers was conducted to identify all cases of SSI following cTSC release during a 10-year study period from 2007 to 2017. Demographic information along with specific microbial culture data and antibiotic sensitivities for each cultured organism were collected. RESULTS: A total of 44 SSIs were identified from a total of 655 cases, with 78 individual organisms isolated. There was an overall SSI rate of 6.7%, with 43% polymicrobial and 66% containing at least one gram-negative organism. Half of SSIs included an organism that was resistant to cefazolin, whereas only 32% of SSIs were completely susceptible to cefazolin. CONCLUSIONS: In this study, gram-negative and polymicrobial infections were responsible for the majority of SSIs following cTSC surgery, with approximately half resistant to cefazolin. Broader gram-negative antibiotic prophylaxis should be considered for this patient population.

Development of best practices in the utilization and implementation of pediatric cervical spine traction: a modified Delphi study.

OBJECTIVE: Cervical traction in pediatric patients is an uncommon but invaluable technique in the management of cervical trauma and deformity. Despite its utility, little empirical evidence exists to guide its implementation, with most practitioners employing custom or modified adult protocols. Expert-based best practices may improve the care of children undergoing cervical traction. In this study, the authors aimed to build consensus and establish best practices for the use of pediatric cervical traction in order to enhance its utilization, safety, and efficacy. METHODS: A modified Delphi method was employed to try to identify areas of consensus regarding the utilization and implementation of pediatric cervical spine traction. A literature review of pediatric cervical traction was distributed electronically along with a survey of current practices to a group of 20 board-certified pediatric neurosurgeons and orthopedic surgeons with expertise in the pediatric cervical spine. Sixty statements were then formulated and distributed to the group. The results of the second survey were discussed during an in-person meeting leading to further consensus. Consensus was defined as ≥ 80% agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree). RESULTS: After the initial round, consensus was achieved with 40 statements regarding the following topics: goals, indications, and contraindications of traction (12), pretraction imaging (6), practical application and initiation of various traction techniques (8), protocols in trauma and deformity patients (8), and management of traction-related complications (6). Following the second round, an additional 9 statements reached consensus related to goals/indications/contraindications of traction (4), related to initiation of traction (4), and related to complication management (1). All participants were willing to incorporate the consensus statements into their practice. CONCLUSIONS: In an attempt to improve and standardize the use of cervical traction in pediatric patients, the authors have identified 49 best-practice recommendations, which were generated by reaching consensus among a multidisciplinary group of pediatric spine experts using a modified Delphi technique. Further study is required to determine if implementation of these practices can lead to reduced complications and improved outcomes for children.

High Prevalence of Gram-Negative Rod and Multi-Organism Surgical Site Infections after Pediatric Complex Tethered Spinal Cord Surgery: Preliminary Report from a Single-Center Study.

BACKGROUND: Surgical site infections (SSIs) are one of the most common complications following pediatric complex tethered spinal cord release. This patient population is similar in some ways to the neuromuscular scoliosis population, in which higher-than-expected rates of gram-negative SSIs have been identified. METHODS: We conducted a single-center retrospective chart review of all patients who underwent complex tethered spinal cord release over a 10-year period between 2007 and 2017. RESULTS: A total of 69 patients were identified, with 10 documented SSIs (14%). 50% of the SSIs were polymicrobial or included at least 1 gram-negative organism. Among the organisms isolated, 3 were fully or -partially resistant to cefazolin, the most common antibiotic prophylaxis in this population. CONCLUSION: Among children undergoing complex tethered spinal cord release, gram-negative and polymicrobial infections are a significant cause of SSIs. Although further multicenter data are needed, these findings suggest that standard antibiotic prophylaxis with cefazolin may not be sufficient.

Pediatric Spine Trauma: A Brief Review.

Pediatric spinal trauma is a broad topic with nuances specific to each anatomic region of the spinal column. The purpose of this report is to provide a brief review highlighting the most important and common clinical issues regarding the diagnosis and management of pediatric spine trauma. Detailed descriptions of imaging findings along with specific operative and nonoperative management of each fracture and dislocation type are beyond the scope of this review.

Multimodal Analgesia After Posterior Fossa Decompression With and Without Duraplasty for Children With Chiari Type I.

BACKGROUND: Multimodal analgesia (MMA) may reduce opioid use after surgery for Chiari malformation type I. An MMA protocol was implemented after both posterior fossa decompression without dural opening (PFD) and posterior fossa decompression with duraplasty (PFDD). METHODS: Scheduled nonsteroidal antiinflammatory drugs (ketorolac or ibuprofen) and diazepam were alternated with acetaminophen, and as-needed oxycodone or intravenous morphine. The primary outcome was total opioid requirement over postoperative days 0 to 2. RESULTS: From 2012 to 2017, 49 PFD and 29 PFDD procedures were performed, and 46 of 78 patients used the protocol. Patients with PFD required less opioids than patients with PFDD. Among patients with PFDD, patients with MMA protocol usage had a lower mean opioid requirement than patients with no MMA protocol usage (0.53 ± 0.49 mgEq/kg versus 1.4 ± 1.0 mgEq/kg, P = .0142). In multivariable analysis, MMA protocol usage status independently predicted a mean decrease in opioid requirement of 0.146 mg equivalents/kg (P = .0497) after adjustment for procedure and surgeon. Statistically significant differences were not demonstrated in antiemetic requirements, discharge opioid prescriptions, total direct cost, and length of stay. CONCLUSIONS: A protocol of scheduled nonsteroidal antiinflammatory drugs alternating with scheduled acetaminophen and diazepam was associated with opioid use reductions.

Opioid-Sparing Multimodal Analgesia After Selective Dorsal Rhizotomy.

OBJECTIVES: Multimodal analgesia (MMA) may reduce opioid use among children who are hospitalized, and may contribute toward enhanced recovery after selective dorsal rhizotomy (SDR) for patients with spasticity in pediatric cerebral palsy. In this retrospective cohort study, we assess an MMA protocol consisting of scheduled nonsteroidal antiinflammatory drug doses (ketorolac or ibuprofen), alternating with scheduled acetaminophen and diazepam doses, with as-needed opioids. It was hypothesized that protocol use would be associated with reductions in opioid requirements and other clinical improvements. METHODS: Data were obtained for 52 patients undergoing SDR at an academic tertiary care pediatric hospital (2012-2017, with the protocol implemented in 2014). Using a retrospective cohort design, we compared outcomes between protocol and nonprotocol patients, employing both univariate t test and Wilcoxon rank test comparisons as well as multivariable regression methods. The primary outcome was total as-needed opioid requirements over postoperative days (PODs) 0 to 2, measured in oral morphine milligram equivalents per kilogram. Additional outcomes included antiemetic medication doses, discharge opioid prescriptions, total direct cost, and length of stay. RESULTS: Twelve patients received the MMA protocol, and 40 patients did not. POD-0 MMA initiation was independently associated with a reduction of 0.14 morphine milligram equivalents per kilogram in mean opioid requirements over PODs 0 to 2 in the multiple regression analysis (95% confidence interval 0.01 to 0.28; P = .04). No statistically significant differences were demonstrated in doses of antiemetic medications, discharge opioid prescriptions, total direct cost, and length of stay. CONCLUSIONS: This MMA protocol may help reduce opioid use after SDR. Improving protocol implementation in a prospective, multisite study will help elucidate further MMA effects on pain, costs, and recovery.

Validation of an effective implantable pump-infusion system for chronic convection-enhanced delivery of intracerebral topotecan in a large animal model.

OBJECTIVE: Intracerebral convection-enhanced delivery (CED) has been limited to short durations due to a reliance on externalized catheters. Preclinical studies investigating topotecan (TPT) CED for glioma have suggested that prolonged infusion improves survival. Internalized pump-catheter systems may facilitate chronic infusion. The authors describe the safety and utility of long-term TPT CED in a porcine model and correlation of drug distribution through coinfusion of gadolinium. METHODS: Fully internalized CED pump-catheter systems were implanted in 12 pigs. Infusion algorithms featuring variable infusion schedules, flow rates, and concentrations of a mixture of TPT and gadolinium were characterized over increasing intervals from 4 to 32 days. Therapy distribution was measured using gadolinium signal on MRI as a surrogate. A 9-point neurobehavioral scale (NBS) was used to identify side effects. RESULTS: All animals tolerated infusion without serious adverse events. The average NBS score was 8.99. The average maximum volume of distribution (Vdmax) in chronically infused animals was 11.30 mL and represented 32.73% of the ipsilateral cerebral hemispheric volume. Vdmax was achieved early during infusions and remained relatively stable despite a slight decline as the infusion reached steady state. Novel tissue TPT concentrations measured by liquid chromatography mass spectroscopy correlated with gadolinium signal intensity on MRI (p = 0.0078). CONCLUSIONS: Prolonged TPT-gadolinium CED via an internalized system is safe and well tolerated and can achieve a large Vdmax, as well as maintain a stable Vd for up to 32 days. Gadolinium provides an identifiable surrogate for measuring drug distribution. Extended CED is potentially a broadly applicable and safe therapeutic option in select patients.

Development of best practices to minimize wound complications after complex tethered spinal cord surgery: a modified Delphi study.

OBJECTIVEComplications after complex tethered spinal cord (cTSC) surgery include infections and cerebrospinal fluid (CSF) leaks. With little empirical evidence to guide management, there is variability in the interventions undertaken to limit complications. Expert-based best practices may improve the care of patients undergoing cTSC surgery. Here, authors conducted a study to identify consensus-driven best practices.METHODSThe Delphi method was employed to identify consensual best practices. A literature review regarding cTSC surgery together with a survey of current practices was distributed to 17 board-certified pediatric neurosurgeons. Thirty statements were then formulated and distributed to the group. Results of the second survey were discussed during an in-person meeting leading to further consensus, which was defined as ≥ 80% agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree).RESULTSSeventeen consensus-driven best practices were identified, with all participants willing to incorporate them into their practice. There were four preoperative interventions: (1, 2) asymptomatic AND symptomatic patients should be referred to urology preoperatively, (3, 4) routine preoperative urine cultures are not necessary for asymptomatic AND symptomatic patients. There were nine intraoperative interventions: (5) patients should receive perioperative cefazolin or an equivalent alternative in the event of allergy, (6) chlorhexidine-based skin preparation is the preferred regimen, (7) saline irrigation should be used intermittently throughout the case, (8) antibiotic-containing irrigation should be used following dural closure, (9) a nonlocking running suture technique should be used for dural closure, (10) dural graft overlay should be used when unable to obtain primary dural closure, (11) an expansile dural graft should be incorporated in cases of lipomyelomeningocele in which primary dural closure does not permit free flow of CSF, (12) paraxial muscles should be closed as a layer separate from the fascia, (13) routine placement of postoperative drains is not necessary. There were three postoperative interventions: (14) postoperative antibiotics are an option and, if given, should be discontinued within 24 hours; (15) patients should remain flat for at least 24 hours postoperatively; (16) routine use of abdominal binders or other compressive devices postoperatively is not necessary. One intervention was prioritized for additional study: (17) further study of additional gram-negative perioperative coverage is needed.CONCLUSIONSA modified Delphi technique was used to develop consensus-driven best practices for decreasing wound complications after cTSC surgery. Further study is required to determine if implementation of these practices will lead to reduced complications. Discussion through the course of this study resulted in the initiation of a multicenter study of gram-negative surgical site infections in cTSC surgery.

Subarachnoid hemorrhage then thrombosis of posterior inferior cerebellar artery dissection: is early surgical exploration warranted?

The natural history of spontaneous cerebral artery dissection and thrombosis remains uncertain. Concurrent subarachnoid hemorrhage further complicates the therapeutic approach. Thus the best strategy for managing patients with acute vessel thrombosis in the setting of subarachnoid hemorrhage is unclear. Here we present a case of spontaneous posterior inferior cerebellar artery dissection presenting with subarachnoid hemorrhage and acute thrombosis. Although the patient was initially managed conservatively, angiographic follow-up demonstrated recanalization of the diseased vessel, necessitating definitive treatment. Thus we propose that angiographic follow-up is necessary in the management of patients with subarachnoid hemorrhage in association with apparent vessel thrombosis.

MMP14 as a novel downstream target of VEGFR2 in migratory glioma-tropic neural stem cells.

Neural stem cell (NSC)-based carriers have been presented as promising therapeutic tools for the treatment of infiltrative brain tumors due to their intrinsic tumor homing property. They have demonstrated the ability to migrate towards distant tumor microsatellites and effectively deliver the therapeutic payload, thus significantly improving survival in experimental animal models for brain tumor. Despite such optimistic results, the efficacy of NSC-based anti-cancer therapy has been limited due to the restricted tumor homing ability of NSCs. To examine this issue, we investigated the mechanisms of tumor-tropic migration of an FDA-approved NSC line, HB1.F3.CD, by performing a gene expression analysis. We identified vascular endothelial growth factor-A (VEGFA) and membrane-bound matrix metalloproteinase (MMP14) as molecules whose expression are significantly elevated in migratory NSCs. We observed increased expression of VEGF receptor 2 (VEGFR2) in the focal adhesion complexes of migratory NSCs, with downstream activation of VEGFR2-dependent kinases such as p-PLCγ, p-FAK, and p-Akt, a signaling cascade reported to be required for cellular migration. In an in vivo orthotopic glioma xenograft model, analysis of the migratory trail showed that NSCs maintained expression of VEGFR2 and preferentially migrated within the perivascular space. Knockdown of VEGFR2 via shRNAs led to significant downregulation of MMP14 expression, which resulted in inhibited tumor-tropic migration. Overall, our results suggest, the involvement of VEGFR2-regulated MMP14 in the tumor-tropic migratory behavior of NSCs. Our data warrant investigation of MMP14 as a target for enhancing the migratory properties of NSC carriers and optimizing the delivery of therapeutic payloads to disseminated tumor burdens.

Subarachnoid hemorrhage then thrombosis of posterior inferior cerebellar artery dissection: is early surgical exploration warranted?

The natural history of spontaneous cerebral artery dissection and thrombosis remains uncertain. Concurrent subarachnoid hemorrhage further complicates the therapeutic approach. Thus the best strategy for managing patients with acute vessel thrombosis in the setting of subarachnoid hemorrhage is unclear. Here we present a case of spontaneous posterior inferior cerebellar artery dissection presenting with subarachnoid hemorrhage and acute thrombosis. Although the patient was initially managed conservatively, angiographic follow-up demonstrated recanalization of the diseased vessel, necessitating definitive treatment. Thus we propose that angiographic follow-up is necessary in the management of patients with subarachnoid hemorrhage in association with apparent vessel thrombosis.

A preclinical evaluation of neural stem cell-based cell carrier for targeted antiglioma oncolytic virotherapy.

BACKGROUND: Oncolytic adenoviral virotherapy (OV) is a highly promising approach for the treatment of glioblastoma multiforme (GBM). In practice, however, the approach is limited by poor viral distribution and spread throughout the tumor mass. METHODS: To enhance viral delivery, replication, and spread, we used a US Food and Drug Administration-approved neural stem cell line (NSC), HB1.F3.CD, which is currently employed in human clinical trials. HB1.F3.CD cells were loaded with an oncolytic adenovirus, CRAd-Survivin-pk7, and mice bearing various human-derived GBMs were assessed with regard to NSC migration, viral replication, and therapeutic efficacy. Survival curves were evaluated with Kaplan-Meier methods. All statistical tests were two-sided. RESULTS: Antiglioma activity of OV-loaded HB1.F3.CD cells was effective against clinically relevant human-derived glioma models as well as a glioma stem cell-enriched xenograft model. Median survival was prolonged by 34% to 50% compared with mice treated with OV alone (GBM43FL model median survival = 19.5 days, OV alone vs NSC + OV, hazard ratio of survival = 2.26, 95% confidence interval [CI] = 1.21 to 12.23, P = .02; GBM12 model median survival = 43.5 days, OV alone vs NSC + OV, hazard ratio of survival = 2.53, 95% CI = 1.21 to 10.38, P = .02). OV-loaded HB1.F3.CD cells were shown to effectively migrate to the contralateral hemisphere and hand off the therapeutic payload of OV to targeted glioma cells. In vivo distribution and migratory kinetics of the OV-loaded HB1.F3.CD cells were successfully monitored in real time by magnetic resonance imaging. OV-loaded NSCs retained their differentiation fate and were nontumorigenic in vivo. CONCLUSIONS: HB1.F3.CD NSCs loaded with CRAd-Survivin-pk7 overcome major limitations of OV in vivo and warrant translation in a phase I human clinical trial for patients with GBM.

A comparative study of neural and mesenchymal stem cell-based carriers for oncolytic adenovirus in a model of malignant glioma.

Glioblastoma multiforme is a primary malignancy of the central nervous system that is universally fatal due to its disseminated nature. Recent investigations have focused on the unique tumor-tropic properties of stem cells as a novel platform for targeted delivery of anticancer agents to the brain. Neural stem cells (NSCs) and mesenchymal stem cells (MSCs) both have the potential to function as cell carriers for targeted delivery of a glioma restricted oncolytic virus to disseminated tumor due to their reported tumor tropism. In this study, we evaluated NSCs and MSCs as cellular delivery vehicles for an oncolytic adenovirus in the context of human glioma. We report the first preclinical comparison of the two cell lines and show that, while both stem cell lines are able to support therapeutic adenoviral replication intracellularly, the amount of virus released from NSCs was a log higher than the MSC (p < 0.001). Moreover, only virus loaded NSCs that were administered intracranially in an orthotopic glioma model significantly prolonged the survival of tumor bearing animals (median survival for NSCs 68.5 days vs 44 days for MSCs, p < 0.002). Loading oncolytic adenovirus into NSCs and MSCs also led to expression of both pro- and anti-inflammatory genes and decreased vector-mediated neuroinflammation. Our results indicate that, despite possessing a comparable migratory capacity, NSCs display superior therapeutic efficacy in the context of intracranial tumors. Taken together, these findings argue in favor of NSCs as an effective cell carrier for antiglioma oncolytic virotherapy.

Neural stem cell-based cell carriers enhance therapeutic efficacy of an oncolytic adenovirus in an orthotopic mouse model of human glioblastoma.

The potential utility of oncolytic adenoviruses as anticancer agents is significantly hampered by the inability of the currently available viral vectors to effectively target micrometastatic tumor burden. Neural stem cells (NSCs) have the ability to function as cell carriers for targeted delivery of an oncolytic adenovirus because of their inherent tumor-tropic migratory ability. We have previously reported that in vivo delivery of CRAd-S-pk7, a glioma-restricted oncolytic adenovirus, can enhance the survival of animals with experimental glioma. In this study, we show that intratumoral delivery of NSCs loaded with the CRAD-S-pk7 in an orthotopic xenograft model of human glioma is able to not only inhibit tumor growth but more importantly to increase median survival by ~50% versus animals treated with CRAd-S-pk7 alone (P = 0.0007). We also report that oncolytic virus infection upregulates different chemoattractant receptors and significantly enhances migratory capacity of NSCs both in vitro and in vivo. Our data further suggest that NSC-based carriers have the potential to improve the clinical efficacy of antiglioma virotherapy by not only protecting therapeutic virus from the host immune system, but also amplifying the therapeutic payload selectively at tumor sites.

Intracerebral estrogen provision increases cytogenesis and neurogenesis in the injured zebra finch brain.

To determine whether or not local, injury-induced aromatization and/or estrogen provision can affect cyto- or neuro-genesis following mechanical brain damage, two groups of adult male zebra finches sustained bilateral penetrating brain injuries. The first received contralateral injections of vehicle or the aromatase inhibitor fadrozole. The second group received contalateral injections of fadrozole, or fadrozole with 17ß-estradiol. Subsequent to injury, birds were injected with the thymidine analog 5-bromo-2'-deoxyuridine (BrdU). Two weeks following injury, the birds were perfused, and coronal sections were labeled using antibodies against BrdU and the neuronal proteins HuC/HuD. In a double blind fashion, BrdU positive cells and BrdU/Hu double-labeled cells in the subventricular zone (SVZ) and at the injury site (INJ) were imaged and sampled. The average numbers of cells per image were compared across brain regions and treatments using repeated measures ANOVAs and, where applicable, post-hoc, pairwise comparisons. Fadrozole administration had no detectable effect on cytogenesis or neurogenesis, however, fadrozole coupled with estradiol significantly increased both measures. The dorsal SVZ had the greatest proportion of new cells that differentiated into neurons, though the highest numbers of BrdU labeled and BrdU, Hu double-labeled cells were detected at the INJ. In the adult zebra finch brain, local estradiol provision can increase cytogenesis and neurogenesis, however, whether or not endogenous glial aromatization is sufficient to similarly affect these processes remains to be seen.

The use of neural stem cells in cancer gene therapy: predicting the path to the clinic.

Gene therapy is a novel means of anticancer treatment that has led to preliminary positive results in the preclinical setting, as well as in clinical trials; however, successful clinical application of this approach has been hampered by the inability of gene delivery systems to target tumors and to deliver a therapeutic payload to disseminated tumor foci efficiently. Along with viral vector systems, various mammalian cells with tropism for tumor cells have been considered as vehicles for delivery of anticancer therapeutics. The discovery of the inherent tumor-tropic properties of neural stem cells (NSCs) has provided a unique opportunity to develop targeted therapies that use NSCs as a vehicle to track invasive tumor cells and deliver anticancer agents selectively to diseased areas. Many in vivo and in vitro studies have demonstrated that the targeted migration of NSCs to infiltrative brain tumors, including malignant glioma, provides a potential therapeutic approach. In this review, the development of NSCs as targeted carriers for anticancer gene therapy is discussed, and barriers in the path to the clinic, as well as approaches to overcoming such barriers are presented.