Abnormal anisotropic diffusion properties in pediatric myelomeningocele patients treated with fetal surgery: an initial DTI study.

PURPOSE: To investigate white matter microstructural abnormality based on diffusion tensor imaging (DTI) in pediatric patients with fetal repair for myelomeningocele (MMC). METHODS: This was a retrospective analysis of DTI data from 8 pediatric patients with prenatal MMC repair (age range 1.64-33.70 months; sex 3F/5M) and 8 age-matched controls (age 2.24-31.20 months; sex 5F/2M). All participants were scanned on 1.5T GE Signa MR scanner (GE Healthcare, Milwaukee, WI) with the same sequence specifications. Two DTI measures, including fractional anisotropy (FA) and mean diffusivity (MD), were calculated from the genu of corpus callosum (gCC) and the posterior limb of internal capsule (PLIC). DTI values and fronto-occipital horn ratio (FOHR) were tested for group difference based on two-tailed paired t test. RESULTS: The ventricle size based on FOHR in patients with prenatal MMC repair was significantly larger than that in the age-matched control group (p < 0.001). Statistically significant group difference in DTI (lower FA and higher MD in patient group) was found in gCC (p = 0.007 and 0.003, respectively). A trend level increase in MD was also found (p = 0.065) in PLIC in patients when compared with the age-matched controls. CONCLUSION: Our data showed white matter abnormality based on DTI in pediatric patient with fetal repair for MMC. The sensitivity of DTI in detecting white matter abnormality, as shown in the present study, may help to serve as an imaging biomarker for assessing hydrocephalus and improve and optimize decision making for the treatment of hydrocephalus in this patient population.

PDE5 inhibitors enhance celecoxib killing in multiple tumor types.

The present studies determined whether clinically relevant phosphodiesterase 5 (PDE5) inhibitors interacted with a clinically relevant NSAID, celecoxib, to kill tumor cells. Celecoxib and PDE5 inhibitors interacted in a greater than additive fashion to kill multiple tumor cell types. Celecoxib and sildenafil killed ex vivo primary human glioma cells as well as their associated activated microglia. Knock down of PDE5 recapitulated the effects of PDE5 inhibitor treatment; the nitric oxide synthase inhibitor L-NAME suppressed drug combination toxicity. The effects of celecoxib were COX2 independent. Over-expression of c-FLIP-s or knock down of CD95/FADD significantly reduced killing by the drug combination. CD95 activation was dependent on nitric oxide and ceramide signaling. CD95 signaling activated the JNK pathway and inhibition of JNK suppressed cell killing. The drug combination inactivated mTOR and increased the levels of autophagy and knock down of Beclin1 or ATG5 strongly suppressed killing by the drug combination. The drug combination caused an ER stress response; knock down of IRE1α/XBP1 enhanced killing whereas knock down of eIF2α/ATF4/CHOP suppressed killing. Sildenafil and celecoxib treatment suppressed the growth of mammary tumors in vivo. Collectively our data demonstrate that clinically achievable concentrations of celecoxib and sildenafil have the potential to be a new therapeutic approach for cancer.

Phosphodiesterase 5 inhibitors enhance chemotherapy killing in gastrointestinal/genitourinary cancer cells.

The present studies determined whether clinically relevant phosphodiesterase 5 (PDE5) inhibitors interacted with clinically relevant chemotherapies to kill gastrointestinal/genitourinary cancer cells. In bladder cancer cells, regardless of H-RAS mutational status, at clinically achievable doses, PDE5 inhibitors interacted in a greater than additive fashion with doxorubicin/mitomycin C/gemcitabine/cisplatin/paclitaxel to cause cell death. In pancreatic tumor cells expressing mutant active K-RAS, PDE5 inhibitors interacted in a greater than additive fashion with doxorubicin/gemcitabine/paclitaxel to cause cell death. The most potent PDE5 inhibitor was sildenafil. Knock down of PDE5 expression recapitulated the combination effects of PDE5 inhibitor drugs with chemotherapy drugs. Expression of cellular FLICE-like inhibitory protein-short did not significantly inhibit chemotherapy lethality but did significantly reduce enhanced killing in combination with sildenafil. Overexpression of B-cell lymphoma-extra large suppressed individual and combination drug toxicities. Knock down of CD95 or Fas-associated death domain protein suppressed drug combination toxicity. Combination toxicity was also abolished by necrostatin or receptor interacting protein 1 knock down. Treatment with PDE5 inhibitors and chemotherapy drugs promoted autophagy, which was maximal at ∼24 hour posttreatment, and 3-methyl adenine or knock down of Beclin1 suppressed drug combination lethality by ∼50%. PDE5 inhibitors enhanced and prolonged the induction of DNA damage as judged by Comet assays and γhistone 2AX (γH2AX) and checkpoint kinase 2 (CHK2) phosphorylation. Knock down of ataxia telangiectasia mutated suppressed γH2AX and CHK2 phosphorylation and enhanced drug combination lethality. Collectively our data demonstrate that the combination of PDE5 inhibitors with standard of care chemotherapy agents for gastrointestinal/genitourinary cancers represents a novel modality.

Giant cell reparative granuloma of the pediatric cranium: case report and review of the literature.

PURPOSE: Giant cell reparative granulomas are rare bone tumors. Although benign, these tumors are locally destructive and can be highly vascular. They seldom occur in the cranial vault. We describe a multidisciplinary approach to a case of giant cell reparative granuloma of the cranium in a 3-year-old patient. CASE REPORT: A 3-year-old girl female referred to the pediatric neurosurgery department for evaluation of a retro-auricular mass. She had a history of recurrent otitis media with two subsequent courses of antibiotics without resolution. CT imaging revealed an expansive lesion located in the right mastoid region. Open surgical biopsy revealed a hemorrhagic tumor consistent with a giant cell reparative granuloma. Angiography identified a hypervascular tumor blush that was supplied by the occipital artery. Preoperative transcatheter embolization was performed followed by a multidisciplinary surgical resection and reconstruction. Blood loss was minimal, and the patient recovered well after surgery. CONCLUSION: Preoperative endovascular embolization and a multidisciplinary intraoperative approach with primary resection and cranial vault reconstruction is an effective approach to hypervascular giant cell reparative granulomas.

Delayed fatal intracranial hemorrhage in a pediatric patient following resection and adjuvant cranial radiotherapy for ependymoma: illustrative case.

BACKGROUND: Cranial radiotherapy (CRT) is an important treatment modality for malignancies of the central nervous system. CRT has deleterious effects that are commonly classified into acute, early delayed, and late delayed. Late-delayed effects include weakening of the cerebral vasculature and the development of structurally abnormal vasculature, potentially leading to ischemic or hemorrhagic events within the brain parenchyma. Such events are not well reported in the pediatric population. OBSERVATIONS: The authors present the case of a 14-year-old patient 8.2 years after CRT who experienced intracerebral hemorrhage. Autopsy demonstrated minimal pathological change without evidence of vascular malformation or aneurysm. These findings were unexpected given the degree of hemorrhage in this case. However, in the absence of other etiologies, it was believed that late-delayed radiation effect was the cause of this patient's fatal hemorrhage. LESSONS: Although not all cases of pediatric spontaneous intracerebral hemorrhage will have a determined etiology, the authors' patient's previous CRT may represent a poorly defined risk for late-delayed hemorrhage. This correlation has not been previously reported and should be considered in pediatric patients presenting with spontaneous hemorrhage in a delayed fashion after CRT. Neurosurgeons must not be dismissive of unexpected events in the remote postoperative period.

PDE5 inhibitors enhance the lethality of standard of care chemotherapy in pediatric CNS tumor cells.

We determined whether clinically relevant phosphodiesterase 5 (PDE5) inhibitors interacted with clinically relevant chemotherapies to kill medulloblastoma cells. In medulloblastoma cells PDE5 inhibitors interacted in a greater than additive fashion with vincristine/etoposide/cisplatin to cause cell death. Knockdown of PDE5 expression recapitulated the combination effects of PDE5 inhibitor drugs with chemotherapy drugs. Expression of dominant negative caspase 9 did not significantly inhibit chemotherapy lethality but did significantly reduce enhanced killing in combination with the PDE5 inhibitor sildenafil. Overexpression of BCL-XL and c-FLIP-s suppressed individual and combination drug toxicities. Knockdown of CD95 or FADD suppressed drug combination toxicity. Treatment with PDE5 inhibitors and chemotherapy drugs promoted autophagy which was maximal at ~12 h post-treatment, and in a cell type-dependent manner knockdown of Beclin1 or ATG5 either suppressed or enhanced drug combination lethality. PDE5 inhibitors enhanced the induction of chemotherapy-induced DNA damage in a nitric oxide synthase-dependent fashion. In conclusion, our data demonstrate that the combination of PDE5 inhibitors with standard of care chemotherapy agents for medulloblastoma represents a possible novel modality for future treatment of this disease.

HDAC inhibitors enhance the lethality of low dose salinomycin in parental and stem-like GBM cells.

The present studies determined whether the antibiotic salinomycin interacted with HDAC inhibitors to kill primary human GBM cells. Regardless of PTEN, ERBB1, or p53 mutational status salinomycin interacted with HDAC inhibitors in a synergistic fashion to kill GBM cells. Inhibition of CD95/Caspase 8 or of CD95/RIP-1/AIF signaling suppressed killing by the drug combination. Salinomycin increased the levels of autophagosomes that correlated with increased p62 and LC3II levels; valproate co-treatment correlated with reduced LC3II and p62 expression, and increased caspase 3 cleavage. Molecular inhibition of autophagosome formation was protective against drug exposure. The drug combination enhanced eIF2α phosphorylation and decreased expression of MCL-1 and phosphorylation of mTOR and p70 S6K. Activation of p70 S6K or mTOR promoted cell survival in the face of combined drug exposure. Overexpression of BCL-XL or c-FLIP-s was protective. Collectively our data demonstrate that the lethality of low nanomolar concentrations of salinomycin are enhanced by HDAC inhibitors in GBM cells and that increased death receptor signaling together with reduced mitochondrial function are causal in the combinatorial drug necro-apoptotic killing effect.

Very early hypothermia induction in patients with severe brain injury (the National Acute Brain Injury Study: Hypothermia II): a randomised trial.

BACKGROUND: The inconsistent effect of hypothermia treatment on severe brain injury in previous trials might be because hypothermia was induced too late after injury. We aimed to assess whether very early induction of hypothermia improves outcome in patients with severe brain injury. METHODS: The National Acute Brain Injury Study: Hypothermia II (NABIS: H II) was a randomised, multicentre clinical trial of patients with severe brain injury who were enrolled within 2·5 h of injury at six sites in the USA and Canada. Patients with non-penetrating brain injury who were 16-45 years old and were not responsive to instructions were randomly assigned (1:1) by a random number generator to hypothermia or normothermia. Patients randomly assigned to hypothermia were cooled to 35°C until their trauma assessment was completed. Patients who had none of a second set of exclusion criteria were either cooled to 33°C for 48 h and then gradually rewarmed or treated at normothermia, depending upon their initial treatment assignment. Investigators who assessed the outcome measures were masked to treatment allocation. The primary outcome was the Glasgow outcome scale score at 6 months. Analysis was by modified intention to treat. This trial is registered with ClinicalTrials.gov, NCT00178711. FINDINGS: Enrolment occurred from December, 2005, to June, 2009, when the trial was terminated for futility. Follow-up was from June, 2006, to December, 2009. 232 patients were initially randomised a mean of 1·6 h (SD 0·5) after injury: 119 to hypothermia and 113 to normothermia. 97 patients (52 in the hypothermia group and 45 in the normothermia group) did not meet any of the second set of exclusion criteria. The mean time to 35°C for the 52 patients in the hypothermia group was 2·6 h (SD 1·2) and to 33°C was 4·4 h (1·5). Outcome was poor (severe disability, vegetative state, or death) in 31 of 52 patients in the hypothermia group and 25 of 56 in the normothermia group (relative risk [RR] 1·08, 95% CI 0·76-1·53; p=0·67). 12 patients in the hypothermia group died compared with eight in the normothermia group (RR 1·30, 95% CI 0·58-2·52; p=0·52). INTERPRETATION: This trial did not confirm the utility of hypothermia as a primary neuroprotective strategy in patients with severe traumatic brain injury.

A crosstalk between myeloma cells and marrow stromal cells stimulates production of DKK1 and interleukin-6: a potential role in the development of lytic bone disease and tumor progression in multiple myeloma.

Multiple myeloma (MM) is a malignancy of antibody-secreting plasma cells. B-cell plasmacytomas stimulate bone resorption and angiogenesis, resulting in osteolytic lesions in the skeleton which persist upon successful treatment of the malignancy with chemotherapy. We found that an interaction between MM cells and mesenchymal stem cells (MSCs) from bone marrow stroma results in the formation and persistence of osteolytic bone lesions. It is known that MM cells activate osteoclast activity and secrete high levels of the Wnt inhibitor, Dickkopf-1, which prevents MSCs from differentiating into osteoblasts. We show that the Wnt signaling activator 6-bromoindirubin-3'-monoxime (BIO) releases MSCs from the osteoinhibitory effects of Dickkopf-1, whereas LiCl treatment does not. Additionally, we show that the >5-kDa fraction of MSC-conditioned medium promotes the proliferation of Dickkopf-1-secreting MM cells and that an interleukin-6 (IL-6)-neutralizing antibody blocks this effect. IL-6 expression levels were higher in undifferentiated MSCs than in MSCs treated with osteogenic medium, remained high in the presence of Dkk1, and were reduced by BIO treatment. Therefore, BIO treatment reduces the MSC-stimulated proliferation of MM cells and may enable MSCs to repair existing osteolytic lesions.

Dkk-1-derived synthetic peptides and lithium chloride for the control and recovery of adult stem cells from bone marrow.

It is established that human mesenchymal stem cells (hMSCs) from bone marrow are a source of osteoblast progenitors in vivo and under appropriate conditions, differentiate into osteoblasts ex vivo. Because hMSCs are recovered by iliac crest aspirate and enriched by virtue of their adherence to tissue culture plastic, the cells provide a convenient ex vivo model for the study of osteogenic tissue repair in an experimentally accessible system. Recent advances in the field of skeletal development and osteogenesis have demonstrated that signaling through the canonical wingless (Wnt) pathway is critical for the differentiation of progenitor cell lines into osteoblasts. Inhibition of such signals can predispose MSCs to cell cycle entry and inhibit osteogenesis. Here, we report that synthetic peptides derived from the second cysteine-rich domain of the canonical Wnt inhibitor Dickkopf-1 (Dkk-1) have utility in controlling the growth and recovery of hMSCs from bone marrow stroma. Three peptides corresponding to residues 217-269 in Dkk-1 were each found to enhance the proliferation of hMSCs in culture over 2 days. The most active peptide exhibited agonistic characteristics in that it ablated the proliferation lag observed when cultures of hMSCs receive fresh medium. It also reduced the expression of endogenous Dkk-1 (Gregory, C. A., Singh, H., and Prockop, D. J. (2003) J. Biol. Chem. 278, 28067-28078). When the cytosolic level of beta-catenin was elevated by addition of LiCl to cultures of hMSCs, the peptide also accelerated degradation of beta-catenin on withdrawal of lithium. A second peptide, corresponding to residues 184-204 had preferential and high affinity for hMSCs in the log phase of proliferation. Peptide overlay assays on hMSC lysates confirmed that the peptide bound to a 184-kDa protein corresponding to the molecular mass of LRP6. Cells recovered by this peptide had enhanced osteogenic potential but less chondrogenic potential compared with controls. Because Wnt antagonists increase the number of non-committed hMSCs in culture, they may be of use in increasing the rate of osseous wound healing in vivo by increasing the level of systemically migrating hMSCs. Therefore, such molecules could contribute to the development of a novel family of pharmaceutical agents for the improvement of the healing process in humans.