Synergy between TMZ and individualized multimodal immunotherapy to improve overall survival of IDH1 wild-type MGMT promoter-unmethylated GBM patients.

The prognosis of IDH1 wild-type MGMT promoter-unmethylated GBM patients remains poor. Addition of Temozolomide (TMZ) to first-line local treatment shifted the median overall survival (OS) from 11.8 to 12.6 months. We retrospectively analyzed the value of individualized multimodal immunotherapy (IMI) to improve OS in these patients. All adults meeting the criteria and treated 06/2015-06/2021 were selected. Thirty-two patients (12f, 20m) had a median age of 47 y (range 18-69) and a KPI of 70 (50-100). Extent of resection was complete (11),

Final results of the Choroid Plexus Tumor study CPT-SIOP-2000.

INTRODUCTION: Standards for chemotherapy against choroid plexus tumors (CPT) have not yet been established. METHODS: CPT-SIOP-2000 (NCT00500890) was an international registry for all CPT nesting a chemotherapy randomization for high-risk CPT with Carboplatin/Etoposide/Vincristine (CarbEV) versus Cyclophosphamide/Etoposide/Vincristine (CycEV). Patients older than three years were recommended to receive irradiation: focal fields for non-metastatic CPC, incompletely resected atypical choroid plexus papilloma (APP) or metastatic choroid plexus papilloma (CPP); craniospinal fields for metastatic CPC/APP and non-responsive CPC. High risk was defined as choroid plexus carcinoma (CPC), incompletely resected APP, and all metastatic CPT. From 2000 until 2010, 158 CPT patients from 23 countries were enrolled. RESULTS: For randomized CPC, the 5/10 year progression free survival (PFS) of patients on CarbEV (n = 20) were 62%/47%, respectively, compared to 27%/18%, on CycEV (n = 15), (intention-to-treat, HR 2.6, p = 0.032). Within the registry, histological grading was the most influential prognostic factor: for CPP (n = 55) the 5/10 year overall survival (OS) and the event free survival (EFS) probabilities were 100%/97% and 92%/92%, respectively; for APP (n = 49) 96%/96% and 76%/76%, respectively; and for CPC (n = 54) 65%/51% and 41%/39%, respectively. Without irradiation, 12 out of 33 patients with CPC younger than three years were alive for a median of 8.52 years. Extent of surgery and metastases were not independent prognosticators. CONCLUSIONS: Chemotherapy for Choroid Plexus Carcinoma is feasible and effective. CarbEV is superior to CycEV. A subset of CPC can be cured without irradiation.

Biological material collection to advance translational research and treatment of children with CNS tumours: position paper from the SIOPE Brain Tumour Group.

Paediatric CNS tumours are the most common cause of childhood cancer-related morbidity and mortality, and improvements in their diagnosis and treatment are needed. New genetic and epigenetic information about paediatric CNS tumours is transforming the field dramatically. For most paediatric CNS tumour entities, subgroups with distinct biological characteristics have been identified, and these characteristics are increasingly used to facilitate accurate diagnoses and therapeutic recommendations. Future treatments will be further tailored to specific molecular subtypes of disease, specific tumour predisposition syndromes, and other biological criteria. Successful biomaterial collection is a key requirement for the application of contemporary methodologies for the validation of candidate prognostic factors, the discovery of new biomarkers, the establishment of appropriate preclinical research models for targeted agents, a quicker clinical implementation of precision medicine, and for other therapeutic uses (eg, for immunotherapies). However, deficits in organisational structures and interdisciplinary cooperation are impeding the collection of high-quality biomaterial from CNS tumours in most centres. Practical, legal, and ethical guidelines for consent, storage, material transfer, biobanking, data sharing, and funding should be established by research consortia and local institutions to allow optimal collection of primary and subsequent tumour tissue, body fluids, and normal tissue. Procedures for the collection and storage of biomaterials and related data should be implemented according to the individual and organisational structures of the local institutions.

Characterization of PD-1 upregulation on tumor-infiltrating lymphocytes in human and murine gliomas and preclinical therapeutic blockade.

Blockade of the immune checkpoint molecule programmed-cell-death-protein-1 (PD-1) yielded promising results in several cancers. To understand the therapeutic potential in human gliomas, quantitative data describing the expression of PD-1 are essential. Moreover, due the immune-specialized region of the brain in which gliomas arise, differences between tumor-infiltrating and circulating lymphocytes should be acknowledged. In this study we have used flow cytometry to quantify PD-1 expression on tumor-infiltrating T cells of 25 freshly resected glioma cell suspensions (10 newly and 5 relapsed glioblastoma, 10 lower grade gliomas) and simultaneously isolated circulating T cells. A strong upregulation of PD-1 expression in the tumor microenvironment compared to the blood circulation was seen in all glioma patients. Additionally, circulating T cells were isolated from 15 age-matched healthy volunteers, but no differences in PD-1 expression were found compared to glioma patients. In the murine GL261 malignant glioma model, there was a similar upregulation of PD-1 on brain-infiltrating lymphocytes. Using a monoclonal PD-1 blocking antibody, we found a marked prolonged survival with 55% of mice reaching long-term survival. Analysis of brain-infiltrating cells 21 days after GL261 tumor implantation showed a shift in infiltrating lymphocyte subgroups with increased CD8+ T cells and decreased regulatory T cells. Together, our results suggest an important role of PD-1 in glioma-induced immune escape, and provide translational evidence for the use of PD-1 blocking antibodies in human malignant gliomas.

CD28/CTLA-4/B7 costimulatory pathway blockade affects regulatory T-cell function in autoimmunity.

Naïve T cells require B7/CD28 costimulation in order to be fully activated. Attempts to block this pathway have been effective in preventing unwanted immune reactions. As B7 blockade might also affect Treg cells and interfere with negative signaling through membrane CTLA-4 on effector T (Teff) cells, its immune-modulatory effects are potentially more complex. Here, we used the mouse model of multiple sclerosis (MS), EAE, to study the effect of B7 blockade. An effective therapy for MS patients has to interfere with ongoing inflammation, and therefore we injected CTLA-4Ig at day 7 and 9 after immunization, when myelin-reactive T cells have been primed and start migrating toward the CNS. Surprisingly, B7 blockade exacerbated disease signs and resulted in more severe CNS inflammation and demyelination, and was associated with an enhanced production of the inflammatory cytokines IL-17 and IFN-γ. Importantly, CTLA-4Ig treatment resulted in a transient reduction of Ki67 and CTLA-4 expression and function of peripheral Treg cells. Taken together, B7 blockade at a particular stage of the autoimmune response can result in the suppression of Treg cells, leading to a more severe disease.

Immunotherapy in atypical teratoid-rhabdoid tumors: Data from a survey of the HGG-Immuno Group.

BACKGROUND AIMS: Atypical rhabdoid/teratoid tumors (AT/RT) are the most common brain tumors in infants and associated with a dismal prognosis. Although intensification of first-line therapy has resulted in improvement of overall survival, novel treatment strategies are needed. Because immunotherapy has resulted in remarkable results in several adult tumor entities, incorporation of immunotherapy into AT/RT treatment offers a novel alternative. METHODS: We retrospectively analyzed data from 7 AT/RT patients from five countries treated within the HGG-Immuno Consortium. Two patients were ≤1 year and 4 patients were ≤2 years of age at diagnosis. All received immunotherapy with autologous, tumor-lysate-loaded dendritic cells (DCs) on a compassionate use basis using a schedule of three to four weekly DC vaccinations with up to 2 × 10(7) DCs per vaccine, followed by three lysate boosts each 1 month apart. RESULTS: Monocyte collections (median age at apheresis 31.5, range 20-143 months) and vaccinations were uneventful without any severe adverse event related to the vaccine, demonstrating feasibility and safety in this very young age group. Two children received immunotherapy during their primary and the remaining five during second- or third-line therapy. Three of seven patients survived long term with a follow-up of 143, 138 and 46 months, with at least two of them harboring somatic mutations. One long-term survivor was vaccinated during primary treatment and the other two after first or second relapse/progression. Two analyzed patients showed positive CD8(+) T-cell responses after vaccination. DISCUSSION: Our data demonstrate that anti-tumor immunotherapy with autologous DCs is feasible and safe in young children with ATRTs and that this approach warrants further investigation in controlled clinical trials.

Diverse Cutaneous Presentations of Langerhans Cell Histiocytosis in Children: A Retrospective Cohort Study.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare disease, frequently affecting young children. PROCEDURE: We performed a retrospective study in patients younger than 16 years old manifesting with skin symptoms, and documented their different cutaneous lesions and systemic symptoms. We compared subgroups of children with single-system, skin-only, and multisystem disease and sought signs predictive for multisystem disease. In a small sample of patients, BRAF mutations were analyzed in archived biopsies. RESULTS: A wide spectrum of cutaneous presentations varying from crusted nodules and papules, blisters, vascular tumor-like lesions, scaling orange to red macules (frequently in seborrheic regions) to purpuric macules, and papules was documented in our cohort of 32 children. Otitis externa was a common manifestation and mucosal lesions were seen in three patients. A novel manifestation was a red-blue nodule that appeared in a patient after a vaccination. None of the cutaneous lesions was predictive for the classification or final outcome as a single-system or multisystem disease. However, later onset and a more protracted course of skin lesions were more frequent findings in multisystem LCH. Mucosal lesions and otitis externa were almost exclusively seen in patients with multisystem disease, a finding that warrants further investigation. Both wild-type (WT) and mutated BRAF were found not only in multisystem LCH, but also in skin-only LCH. Two cases with rapidly resolving congenital lesions had WT BRAF. CONCLUSIONS: Late onset and a protracted course of skin lesions are associated with MS-LCH, whereas WT BRAF is found in rapidly resolving skin lesions.

Newcastle disease virotherapy induces long-term survival and tumor-specific immune memory in orthotopic glioma through the induction of immunogenic cell death.

The oncolytic features of several naturally oncolytic viruses have been shown on Glioblastoma Multiforme cell lines and in xenotransplant models. However, orthotopic glioma studies in immunocompetent animals are lacking. Here we investigated Newcastle disease virus (NDV) in the orthotopic, syngeneic murine GL261 model. Seven days after tumor induction, mice received NDV intratumorally. Treatment significantly prolonged median survival and 50% of animals showed long-term survival. We demonstrated immunogenic cell death (ICD) induction in GL261 cells after NDV infection, comprising calreticulin surface exposure, release of HMGB1 and increased PMEL17 cancer antigen expression. Uniquely, we found absence of secreted ATP. NDV-induced ICD occurred independently of caspase signaling and was blocked by Necrostatin-1, suggesting the contribution of necroptosis. Autophagy induction following NDV infection of GL261 cells was demonstrated as well. In vivo, elevated infiltration of IFN-γ(+) T cells was observed in NDV-treated tumors, along with reduced accumulation of myeloid derived suppressor cells. The importance of a functional adaptive immune system in this paradigm was demonstrated in immunodeficient Rag2(-/-) mice and in CD8(+) T cell depleted animals, where NDV slightly prolonged survival, but failed to induce long-term cure. Secondary tumor induction with GL261 cells or LLC cells in mice surviving long-term after NDV treatment, demonstrated the induction of a long-term, tumor-specific immunological memory response by ND virotherapy. For the first time, we describe the therapeutic activity of NDV against GL261 tumors, evidenced in an orthotopic mouse model. The therapeutic effect relies on the induction of ICD in the tumor cells, which primes adaptive antitumor immunity.

Glioma-derived galectin-1 regulates innate and adaptive antitumor immunity.

Galectin-1 is a glycan-binding protein, which is involved in the aggressiveness of glioblastoma (GBM) in part by stimulating angiogenesis. In different cancer models, galectin-1 has also been demonstrated to play a pivotal role in tumor-mediated immune evasion especially by modulating cells of the adaptive immune system. It is yet unknown whether the absence or presence of galectin-1 within the glioma microenvironment also causes qualitative or quantitative differences in innate and/or adaptive antitumor immune responses. All experiments were performed in the orthotopic GL261 mouse high-grade glioma model. Stable galectin-1 knockdown was achieved via transduction of parental GL261 tumor cells with a lentiviral vector encoding a galectin-1-targeting miRNA. We demonstrated that the absence of tumor-derived but not of host-derived galectin-1 significantly prolonged the survival of glioma-bearing mice as such and in combination with dendritic cell (DC)-based immunotherapy. Both flow cytometric and pathological analysis revealed that the silencing of glioma-derived galectin-1 significantly decreased the amount of brain-infiltrating macrophages and myeloid-derived suppressor cells (MDSC) in tumor-bearing mice. Additionally, we revealed a pro-angiogenic role for galectin-1 within the glioma microenvironment. The data provided in this study reveal a pivotal role for glioma-derived galectin-1 in the regulation of myeloid cell accumulation within the glioma microenvironment, the most abundant immune cell population in high-grade gliomas. Furthermore, the prolonged survival observed in untreated and DC-vaccinated glioma-bearing mice upon the silencing of tumor-derived galectin-1 strongly suggest that the in vivo targeting of tumor-derived galectin-1 might offer a promising and realistic adjuvant treatment modality in patients diagnosed with GBM.

Foxp3+ regulatory T cells are activated in spite of B7-CD28 and CD40-CD40L blockade.

Costimulatory signals are required for priming and activation of naive T cells, while it is less clear how they contribute to induction of regulatory T (Treg)-cell activity. We previously reported that the blockade of the B7-CD28 and CD40L-CD40 interaction efficiently suppresses allogeneic T-cell activation in vivo. This was characterized by an initial rise in Foxp3(+) cells, followed by depletion of host-reactive T cells. To further investigate effects of costimulatory blockade on Treg cells, we used an in vitro model of allogeneic CD4(+) cell activation. When CTLA-4Ig and anti-CD40L mAb (MR1) were added to the cultures, T-cell proliferation and IL-2 production were strongly reduced. However, Foxp3(+) cells proliferated and acquired suppressive activity. They suppressed activation of syngeneic CD4(+) cells much more efficiently than did freshly isolated Treg cells. CD4(+) cells activated by allogeneic cells in the presence of MR1 and CTLA-4Ig were hyporesponsive on restimulation, but their response was restored to that of naive CD4(+) cells when Foxp3(+) Treg cells were removed. We conclude that natural Treg cells are less dependent on B7-CD28 or CD40-CD40L costimulation compared with Foxp3(-) T cells. Reduced costimulation therefore alters the balance between Teff and Treg-cell activation in favor of Treg-cell activity.

Development and validation of a fully GMP-compliant production process of autologous, tumor-lysate-pulsed dendritic cells.

BACKGROUND AND AIMS: One of the major challenges of dendritic cell (DC) vaccination is the establishment of harmonized DC production protocols. Here, we report the transfer and validation of a successfully used open DC manufacturing method into a closed system, good manufacturing practice (GMP)-compatible protocol. METHODS: All production steps (lysate generation, monocyte selection, DC culture and cryopreservation) were standardized and validated. RESULTS: Tumor lysate was characterized by histology, mechanically homogenized and avitalized. This preparation yielded a median of 58 ± 21 µg protein per milligram of tumor tissue. Avitality was determined by trypan blue staining and confirmed in an adenosine triphosphate release assay. Patient monocytes were isolated by elutriation or CD14 selection, which yielded equivalent results. DCs were subsequently differentiated in Teflon bags for an optimum of 7 days in CellGro medium supplemented with interleukin (IL)-4 and granulocyte macrophage colony stimulating factor and then matured for 48 h in tumor necrosis factor-α and IL-1ß after pulsing with tumor lysate. This protocol resulted in robust and reproducible upregulation of DC maturation markers such as cluster of differentiation (CD)80, CD83, CD86, human leukocyte antigen-DR and DC-SIGN. Functionality of these DCs was shown by directed migration toward C-C motif chemokine ligand 19/21, positive T-cell stimulatory capacity and the ability to prime antigen-specific T cells from naive CD8(+) T cells. Phenotype stability, vitality and functionality of DCs after cryopreservation, thawing and washing showed no significant loss of function. Comparison of clinical data from 146 patients having received vaccinations with plate-adherence versus GMP-grade DCs showed no inferiority of the latter. CONCLUSIONS: Our robust, validated and approved protocol for DC manufacturing forms the basis for a harmonized procedure to produce cancer vaccines, which paves the way for larger multi-center clinical trials.

Methods behind oncolytic virus-based DC vaccines in cancer: Toward a multiphase combined treatment strategy for Glioblastoma (GBM) patients.

Glioblastoma (GBM) remains an orphan cancer disease with poor outcome. Novel treatment strategies are needed. Immunotherapy has several modes of action. The addition of active specific immunotherapy with dendritic cell vaccines resulted in improved overall survival of patients. Integration of DC vaccination within the first-line combined treatment became a challenge, and immunogenic cell death immunotherapy during chemotherapy was introduced. We used a retrospective analysis using real world data to evaluate the complex combined treatment, which included individualized multimodal immunotherapy during and after standard of care, and which required adaptations during treatment, and found a further improvement of overall survival. We also discuss the use of real world data as evidence. Novel strategies to move the field of individualized multimodal immunotherapy forward for GBM patients are reviewed.

Immunological characteristics of human mesenchymal stem cells and multipotent adult progenitor cells.

Somatic, also termed adult, stem cells are highly attractive biomedical cell candidates because of their extensive replication potential and functional multilineage differentiation capacity. They can be used for drug and toxicity screenings in preclinical studies, as in vitro model to study differentiation or for regenerative medicine to aid in the repair of tissues or replace tissues that are lost upon disease, injury or ageing. Multipotent adult progenitor cells (MAPCs) and mesenchymal stem cells (MSCs) are two types of adult stem cells derived from bone marrow that are currently being used clinically for tissue regeneration and for their immunomodulatory and trophic effects. This review will give an overview of the phenotypic and functional differences between human MAPCs and MSCs, with a strong emphasis on their immunological characteristics. Finally, we will discuss the clinical studies in which MSCs and MAPCs are already used.

Reproducibility of rapid short echo time CSI at 3 tesla for clinical applications.

PURPOSE: To validate the reproducibility of a chemical shift imaging (CSI) acquisition protocol with parallel imaging, using automated repositioning software. MATERIALS AND METHODS: Ten volunteers were imaged three times on two different 3 Tesla (T) MRI scanners, receiving anatomical imaging and two identical CSI measurements, using automated repositioning software for consistent repositioning of the CSI grid. Offcenter parameters of the CSI plane were analyzed. Coefficients of variation (CoV), Cramér-Rao lower bounds (CRLB), intraclass correlation coefficients (ICC), and coefficients of repeatability (CoR) for immediate repetition and between scanners were calculated for N-acetylaspartate, total choline, creatine, myo-inositol (Myo) and glutamine+glutamate (Glx). Proportions of variance reflecting the effect of voxel location, volunteer, repetition, time instance and scanner were calculated from an analysis of variance analysis. RESULTS: The offcenter vector and angulations of the CSI grid differed less than 1 mm and 2° between all measurements. The mean CoV and CRLB were less than 30% for all metabolites, except for Myo. The variance due to voxel location in the volume of interest and the error represent the largest contributions in variability. The ICC is the lowest for Myo and Glx. CoR for immediate repetition and between scanners display values between 22 and 83%. CONCLUSION: We propose a CSI protocol with acceptable reproducibility, applicable in clinical routine.

Altered galectin-1 serum levels in patients diagnosed with high-grade glioma.

High-grade gliomas (HGG) are the most common and most aggressive intrinsic human brain tumors in adults. Galectin-1, a glycan-binding protein that is overexpressed in HGG, has been shown to contribute significantly to the aggressive nature of HGG. It is unknown whether increased galectin-1 expression levels are exclusively found at the tumor site or whether galectin-1 can also be detected in the serum of HGG patients. Galectin-1 serum levels were analyzed in a prospective dataset of 43 healthy controls and 125 patients with newly diagnosed or recurrent HGG. Samples were taken at the moment of surgical resection and/or 2-3 weeks after surgery. Galectin-1 serum levels were determined using an ELISA for galectin-1. Galectin-1 serum levels depended significantly on age and sex in the control group. Age- and sex-adjusted galectin-1 serum levels were significantly higher in all patient subgroups compared to healthy controls with a high discriminative ability that increased with age. We did not observe a significant decrease in the galectin-1 serum levels upon surgical resection of the tumor. Collectively, the data presented here may represent a first step to establish galectin-1 as a biomarker in HGG disease monitoring. Further longitudinal evaluation is required and ongoing to investigate the value of galectin-1 serum levels in HGG patients as an additional diagnostic marker, but more importantly as a predictor of treatment response and prognosis. Furthermore, galectin-1 serum levels could also provide an important tool for the identification of HGG patients that could benefit from galectin-1 directed therapies that are currently under development.

Individualized Multimodal Immunotherapy for Adults with IDH1 Wild-Type GBM: A Single Institute Experience.

Synergistic activity between maintenance temozolomide (TMZm) and individualized multimodal immunotherapy (IMI) during/after first-line treatment has been suggested to improve the overall survival (OS) of adults with IDH1 wild-type MGMT promoter-unmethylated (unmeth) GBM. We expand the data and include the OS of MGMT promoter-methylated (meth) adults with GBM. Unmeth (10 f, 18 m) and meth (12 f, 10 m) patients treated between 27 May 2015 and 1 January 2022 were analyzed retrospectively. There were no differences in age (median: 48 y) or Karnofsky performance index (median: 80). The IMI consisted of 5-day immunogenic cell death (ICD) therapies during TMZm: Newcastle disease virus (NDV) bolus injections and sessions of modulated electrohyperthermia (mEHT); subsequent active specific immunotherapy: dendritic cell (DC) vaccines plus modulatory immunotherapy; and maintenance ICD therapy. There were no differences in the number of vaccines (median: 2), total number of DCs (median: 25.6 × 106), number of NDV injections (median: 31), and number of mEHT sessions (median: 28) between both groups. The median OS of 28 unmeth patients was 22 m (2y-OS: 39%), confirming previous results. OS of 22 meth patients was significantly better (p = 0.0414) with 38 m (2y-OS: 81%). There were no major treatment-related adverse reactions. The addition of IMI during/after standard of care should be prospectively explored.

The Application of Evidence-Based Medicine in Individualized Medicine.

The fundamental aim of healthcare is to improve overall health of the population by providing state-of-the-art healthcare for individuals at an affordable cost. The foundation for this system is largely referred to as "evidence-based medicine". Too often, evidence-based medicine is based solely on so-called "best research evidence", collected through randomized controlled trials while disregarding clinical expertise and patient expectations. As healthcare gravitates towards personalized and individualized medicine, such external clinical (research) evidence can inform, but never replace, individual clinical expertise. This applies in particular to orphan diseases, for which clinical trials are methodologically particularly problematic, and evidence derived from them is often questionable. Evidence-based medicine constitutes a complex process to allow doctors and patients to select the best possible solutions for each individual based on rapidly developing new therapeutic directions. This requires a revisit of the foundations of evidence-based medicine. A proposition as to how to manage evidence-based data in individualized immune-oncology is presented here.

Integration of autologous dendritic cell-based immunotherapy in the standard of care treatment for patients with newly diagnosed glioblastoma: results of the HGG-2006 phase I/II trial.

PURPOSE: Dendritic cell (DC)-based tumor vaccination has rendered promising results in relapsed high-grade glioma patients. In the HGG-2006 trial (EudraCT 2006-002881-20), feasibility, toxicity, and clinical efficacy of the full integration of DC-based tumor vaccination into standard postoperative radiochemotherapy are studied in 77 patients with newly diagnosed glioblastoma. PATIENTS AND METHODS: Autologous DC are generated after leukapheresis, which is performed before the start of radiochemotherapy. Four weekly induction vaccines are administered after the 6-week course of concomitant radiochemotherapy. During maintenance chemotherapy, 4 boost vaccines are given. Feasibility and progression-free survival (PFS) at 6 months (6mo-PFS) are the primary end points. Overall survival (OS) and immune profiling, rather than monitoring, as assessed in patients' blood samples, are the secondary end points. Analysis has been done on intent-to-treat basis. RESULTS: The treatment was feasible without major toxicity. The 6mo-PFS was 70.1 % from inclusion. Median OS was 18.3 months. Outcome improved significantly with lower EORTC RPA classification. Median OS was 39.7, 18.3, and 10.7 months for RPA classes III, IV, and V, respectively. Patients with a methylated MGMT promoter had significantly better PFS (p = 0.0027) and OS (p = 0.0082) as compared to patients with an unmethylated status. Exploratory "immunological profiles" were built to compare to clinical outcome, but no statistical significant evidence was found for these profiles to predict clinical outcome. CONCLUSION: Full integration of autologous DC-based tumor vaccination into standard postoperative radiochemotherapy for newly diagnosed glioblastoma seems safe and possibly beneficial. These results were used to power the currently running phase IIb randomized clinical trial.

Gliomas: diffusion kurtosis MR imaging in grading.

PURPOSE: To assess the diagnostic accuracy of diffusion kurtosis magnetic resonance imaging parameters in grading gliomas. MATERIALS AND METHODS: The institutional review board approved this prospective study, and informed consent was obtained from all patients. Diffusion parameters-mean diffusivity (MD), fractional anisotropy (FA), mean kurtosis, and radial and axial kurtosis-were compared in the solid parts of 17 high-grade gliomas and 11 low-grade gliomas (P<.05 significance level, Mann-Whitney-Wilcoxon test, Bonferroni correction). MD, FA, mean kurtosis, radial kurtosis, and axial kurtosis in solid tumors were also normalized to the corresponding values in contralateral normal-appearing white matter (NAWM) and the contralateral posterior limb of the internal capsule (PLIC) after age correction and were compared among tumor grades. RESULTS: Mean, radial, and axial kurtosis were significantly higher in high-grade gliomas than in low-grade gliomas (P = .02, P = .015, and P = .01, respectively). FA and MD did not significantly differ between glioma grades. All values, except for axial kurtosis, that were normalized to the values in the contralateral NAWM were significantly different between high-grade and low-grade gliomas (mean kurtosis, P = .02; radial kurtosis, P = .03; FA, P = .025; and MD, P = .03). When values were normalized to those in the contralateral PLIC, none of the considered parameters showed significant differences between high-grade and low-grade gliomas. The highest sensitivity and specificity for discriminating between high-grade and low-grade gliomas were found for mean kurtosis (71% and 82%, respectively) and mean kurtosis normalized to the value in the contralateral NAWM (100% and 73%, respectively). Optimal thresholds for mean kurtosis and mean kurtosis normalized to the value in the contralateral NAWM for differentiating high-grade from low-grade gliomas were 0.52 and 0.51, respectively. CONCLUSION: There were significant differences in kurtosis parameters between high-grade and low-grade gliomas; hence, better separation was achieved with these parameters than with conventional diffusion imaging parameters.

Differentiation potential of human postnatal mesenchymal stem cells, mesoangioblasts, and multipotent adult progenitor cells reflected in their transcriptome and partially influenced by the culture conditions.

Several adherent postnatal stem cells have been described with different phenotypic and functional properties. As many of these cells are being considered for clinical therapies, it is of great importance that the identity and potency of these products is validated. We compared the phenotype and functional characteristics of human mesenchymal stem cells (hMSCs), human mesoangioblasts (hMab), and human multipotent adult progenitor cells (hMAPCs) using uniform standardized methods. Human MAPCs could be expanded significantly longer in culture. Differences in cell surface marker expression were found among the three cell populations with CD140b being a distinctive marker among the three cell types. Differentiation capacity towards adipocytes, osteoblasts, chondrocytes, and smooth muscle cells in vitro, using established protocols, was similar among the three cell types. However, only hMab differentiated to skeletal myocytes, while only hMAPCs differentiated to endothelium in vitro and in vivo. A comparative transcriptome analysis confirmed that the three cell populations are distinct and revealed gene signatures that correlated with their specific functional properties. Furthermore, we assessed whether the phenotypic, functional, and transcriptome features were mediated by the culture conditions. Human MSCs and hMab cultured under MAPC conditions became capable of generating endothelial-like cells, whereas hMab lost some of their ability to generate myotubes. By contrast, hMAPCs cultured under MSC conditions lost their endothelial differentiation capacity, whereas this was retained when cultured under Mab conditions, however, myogenic capacity was not gained under Mab conditions. These studies demonstrate that hMSCs, hMab, and hMAPCs have different properties that are partially mediated by the culture conditions.