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Biomedical subjects

Andreas Unterberg

Publications and source records attributed to Andreas Unterberg.

16 recordsLinked to original sources

Individualized patient tumor organoids faithfully preserve human brain tumor ecosystems and predict patient response to therapy.

Tumor organoids are important tools for cancer research, but current models have drawbacks that limit their applications for predicting response to therapy. Here, we developed a fast, efficient, and complex culture system (IPTO, individualized patient tumor organoid) that accurately recapitulates the cellular and molecular pathology of human brain tumors. Patient-derived tumor explants were cultured in induced pluripotent stem cell (iPSC)-derived cerebral organoids, thus enabling culture of a wide range of human tumors in the central nervous system (CNS), including adult, pediatric, and metastatic brain cancers. Histopathological, genomic, epigenomic, and single-cell RNA sequencing (scRNA-seq) analyses demonstrated that the IPTO model recapitulates cellular heterogeneity and molecular features of original tumors. Crucially, we showed that the IPTO model predicts patient-specific drug responses, including resistance mechanisms, in a prospective patient cohort. Collectively, the IPTO model represents a major breakthrough in preclinical modeling of human cancers, which provides a path toward personalized cancer therapy.

Humans↗

Comparative analysis of in vitro conditions for rat adult neural progenitor cells.

Various protocols have been published for in vitro expansion and maintenance of adult neural progenitor cells (ANPC). However, there are only few data comparing these protocols regarding their influence on proliferation, migration and differentiation. Freshly isolated ANPC from olfactory bulb (BO) and dentate gyrus (DG) of adult rat brains forming neurospheres and expressing the neural stem cell markers nestin and Sox-2 were used in a comparative analysis of five different medium combinations. Medium containing N2 and fetal calf serum (FCS), but no additional cytokines was unsuitable for an effective long-term expansion of ANPC due to a significantly reduced proliferation rate. Media containing BIT, basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), platelet-derived growth factor AB (PDGF-AB) and leukemia inhibitory factor (LIF) or B27, bFGF and EGF are recommendable for the cultivation of DG-derived ANPC as neurospheres only. Unlike, culture media containing BIT, bFGF, EGF and PDGF-AB or N2, bFGF and EGF were suitable for all applications tested as they responded similarly regarding proliferation, migration and expression of differentiation markers. The results of the present study might help to improve the effective in vitro expansion of ANPC derived from rare human tissue samples.

Adult Stem Cells↗

Recommendations for the management of intracranial haemorrhage - part I: spontaneous intracerebral haemorrhage. The European Stroke Initiative Writing Committee and the Writing Committee for the EUSI Executive Committee.

This article represents the recommendations for the management of spontaneous intracerebral haemorrhage of the European Stroke Initiative (EUSI). These recommendations are endorsed by the 3 European societies which are represented in the EUSI: the European Stroke Council, the European Neurological Society and the European Federation of Neurological Societies.

Emergency Medical Services↗

Different angiogenic phenotypes in primary and secondary glioblastomas.

Primary and secondary glioblastomas (pGBM, sGBM) are supposed to evolve through different genetic pathways, including EGF receptor and PDGF and its receptor and thus genes that are involved in tumor-induced angiogenesis. However, whether other angiogenic cytokines are also differentially expressed in these glioblastoma subtypes is not known so far, but this knowledge might be important to optimize an antiangiogenic therapy. Therefore, we studied the expression of several angiogenic cytokines, including VEGF-A, HGF, bFGF, PDGF-AB, PDGF-BB, G-CSF and GM-CSF in pGBMs and sGBMs as well as in gliomas WHO III, the precursor lesions of sGBMs. In tumor tissues, expression of all cytokines was observed albeit with marked differences concerning intensity and distribution pattern. Quantification of the cytokines in the supernatant of 30 tissue-corresponding glioma cultures revealed a predominant expression of VEGF-A in pGBMs and significantly higher expression levels of PDGF-AB in sGBMs. HGF and bFGF were determined in nearly all tumor cultures but with no GBM subtype or malignancy-related differences. Interestingly, GM-CSF and especially G-CSF were produced less frequently by tumor cells. However, GM-CSF secretion occurred together with an increased number of simultaneously secreted cytokines and correlated with a worse patient prognosis and may thus represent a more aggressive angiogenic phenotype. Finally, we confirmed an independent contribution of each tumor-derived cytokine analyzed to tumor-induced vascularization. Our data indicate that an optimal antiangiogenic therapy may require targeting of multiple angiogenic pathways that seem to differ markedly in pGBMs and sGBMs.

Adolescent↗

Epidermal growth factor receptor inhibition for the treatment of glioblastoma multiforme and other malignant brain tumours.

Gliomas are the most common primary central nervous system tumours and about 55% are glioblastoma multiforme (GBM). Between 40% and 50% of GBM have dysregulated epidermal growth factor receptor (HER1/EGFR), and almost half of these co-express the mutant receptor subtype EGFRvIII, which may contribute to the aggressive and refractory course of GBM. Limited therapeutic options exist for GBM, and recurrence is common. Standard therapy is surgical resection, where possible, and radiotherapy. Adjuvant chemotherapy provides a modest survival benefit. New therapies are essential, and HER1/EGFR-targeted agents may provide a viable strategy. The HER1/EGFR tyrosine kinase inhibitors erlotinib and gefitinib are in advanced clinical development for glioma, and a number of trials are in progress, or have recently been completed. Preliminary results with gefitinib show no objective responses, but do provide evidence of disease control. In contrast, preliminary data with erlotinib appear more encouraging. Erlotinib inhibits wild-type HER1/EGFR and EGFRvIII, which may underlie its promising clinical activity. Other HER1/EGFR-targeted agents are also being investigated for glioma, including monoclonal antibodies, radio-immuno conjugates, ligand-toxin conjugates, antisense oligonucleotides and ribozymes. Further studies will define their clinical potential and hopefully provide new, effective treatments for GBM and other malignant brain tumours.

Brain Neoplasms↗

Motor cortex stimulation for long-term relief of chronic neuropathic pain: a 10 year experience.

Chronic subthreshold stimulation of the contralateral precentral gyrus is used in patients with intractable neuropathic pain for more than 15 years. The aim of this study was to analyse retrospectively our own patient group with long term follow-up of 10 years. Seventeen patients with chronic neuropathic pain were treated with contralateral epidural stimulation electrodes. In 10 cases, trigeminal neuropathic pain (TNP) and in seven cases post-stroke pain (PSP) were diagnosed. The placement of the electrodes was performed in local anaesthesia using neuronavigation and intraoperative neuromonitoring. A test trial of minimum one week including double-blind testing was conducted and pain intensity was measured using a visual analogue scale (VAS). Correct placement of the electrode was achieved in all patients using intraoperative neurophysiological monitoring. Double-blind testing was able to identify 6 (35%) non-responders. In 5 of 10 (50%) with TNP and 3 of 7 (43%) with PSP a positive effect with pain reduction > or = 50% was observed. The mean follow-up period was 3.6 years (range 1-10 years) and includes a patient with 10 years of positive stimulation effect. Stimulation of the motor cortex is a treatment option for patients with chronic neuropathic pain localized in the face or upper extremity. Double-blind testing can identify non-responders. Patients with TNP profit more than patients with PSP. The positive effect can last for ten years in long-term follow-up.

Adult↗

Antiglioma activity of 2,2':6',2"-terpyridineplatinum(II) complexes in a rat model--effects on cellular redox metabolism.

The mammalian thioredoxin system, comprising the selenoenzyme thioredoxin reductase (TrxR) and the 12-kDa protein thioredoxin (Trx), is implicated in thiol-mediated antioxidant defense and redox regulatory processes including transcriptional control, DNA synthesis, and apoptosis. Cell proliferation supported by the thioredoxin system can be suppressed by TrxR inhibition. In this study, we assessed the effects of the potent hTrxR inhibitors 4-mercaptopyridine (4'-chloro-2,2':6',2"-terpyridine)platinum nitrate (I(23)2N) and 2-mercaptopyridine (4'-chloro-2,2':6',2"-terpyridine)platinum nitrate (I(25)2N) on glioblastoma in a rat model. These compounds show no or little cross-resistance with cisplatin and are thus of great clinical interest. Triple intravenous application of 25-35 mg/kg of the compounds led to a significant decrease of tumor growth as determined by magnetic resonance imaging. Metabolic as well as redox parameters in the blood of the animals were not altered. However, TrxR activity was significantly decreased in the tumor tissue, and redox parameters-including glutathione concentrations, total antioxidant status, and the activities of different antioxidant enzymes-showed tissue-specific variations. As indicated by different apoptotic markers, the antitumor activity of I(23)2N is not mediated by the induction of programmed cell death but rather by hTrxR inhibition and DNA intercalation leading to cell cycle arrest.

Animals↗

Using video-oculography for galvanic evoked vestibulo-ocular monitoring in comatose patients.

Binocular eye movement responses to galvanic vestibular stimulation were measured in comatose patients. Healthy persons have been demonstrated to show a consistent and reproducible relationship between eye movement and galvanic vestibular stimulation. Any pathology of the vestibular integrating structures (brainstem and to some degree the cerebellum and cortex) is assumed to influence this response pathognomonically. A monitoring facility was designed to record eye movements during galvanic labyrinth polarization (GaLa) in order to examine the vestibular response in comatose patients. GaLa was applied by means of two pairs of electrodes attached between the mastoid and interscapular region. A custom-built, battery-driven current-source stimulator served to generate sinusoidal stimuli that could be applied either unilaterally or simultaneously and independently to the left and right labyrinths. The resultant binocular eye movements were recorded using a Chronos Eye Tracker and the digital image sequences stored for subsequent analysis. Repeated testing was performed in five comatose patients with a Glasgow Coma Score of 3, who were intubated and ventilated (subarachnoid hemorrhage (n = 3), traumatic injury (n = 2)). The observed ocular movements varied. In four cases ocular movements in response to GaLa were observed, while one patient showed neither spontaneous nor galvanic-induced eye movements. The latter was diagnosed as brain-dead 2 days after testing. In contrast, the patients who showed ocular movements synchronous with galvanic stimulation left the intensive care unit (ICU) for rehabilitation. These data indicate that it is possible to assess brain function in comatose patients by evaluating the vestibulo-ocular response to galvanic stimulation. The designed monitoring facility can be used on the ICU ward without disconnection of other monitoring equipment.

Brain↗

Consensus meeting on microdialysis in neurointensive care.

BACKGROUND: Microdialysis is used in many European neurointensive care units to monitor brain chemistry in patients suffering subarachnoid hemorrhage (SAH) or traumatic brain injury (TBI). DISCUSSION: We present a consensus agreement achieved at a meeting in Stockholm by a group of experienced users of microdialysis in neurointensive care, defining the use of microdialysis, placement of catheters, unreliable values, chemical markers, and clinical use in SAH and in TBI. CONCLUSIONS: As microdialysis is maturing into a clinically useful technique for early detection of cerebral ischemia and secondary brain damage, there is a need to following such definition regarding when and how to use microdialysis after SAH and TBI.

Brain Injuries↗

Acute focal neurological deficits in aneurysmal subarachnoid hemorrhage: relation of clinical course, CT findings, and metabolite abnormalities monitored with bedside microdialysis.

BACKGROUND AND PURPOSE: We sought (1) to identify early metabolic markers for the development of (ir)reversible neurological deficits and cerebral infarction in subarachnoid hemorrhage (SAH) patients by using the microdialysis technique and (2) to evaluate the influence of intracerebral hemorrhage (ICH) on microdialysis parameters. METHODS: We performed a prospective study of 44 SAH patients with acute focal neurological deficits (AFND) occurring acutely with SAH (due to ICH) or directly after surgery (due to clip stenosis, thromboembolism, or early edema). Fifty-one nonischemic SAH patients served as a control group. A microdialysis catheter was inserted into the vascular territory of the aneurysm after clipping. The microdialysates were analyzed hourly for extracellular glucose, lactate, lactate/pyruvate ratio, glutamate, and glycerol with a bedside analyzer. Microdialysis-related CT findings were evaluated for the presence of ICH and cerebral infarction. Reversibility of neurological symptoms after 4 weeks and 6- and 12-month outcomes were assessed. RESULTS: In patients with AFND, cerebral metabolism was severely disturbed when microdialysis started compared with controls (P<0.005). Infarction on CT was associated with pathological microdialysis parameters (P<0.002) and development of a fixed deficit (P<0.003), while the presence of ICH alone was not. A secondary neurological deterioration of AFND patients (n=11) was reflected by preceding (0 to 20 hours) changes of microdialysate concentrations. CONCLUSIONS: In the presence of ICH, pathological microdialysis values may indicate reversible tissue damage. Extreme microdialysis values and pathological microdialysis concentrations that further deteriorate 2-fold are highly indicative of the development of cerebral infarction and permanent neurological deficits. Therefore, the analysis of relative changes of microdialysis parameters is crucial for the detection of ischemia in SAH patients.

Acute Disease↗

Pulmonary air embolism in severe head injury.

Entry of air into the venous system leading to intracardiac air and pulmonary air embolism (PAE) has been reported in various clinical settings such as neurosurgical interventions in the sitting position and in autopsies on patients with head and neck injuries. We report the case of a 29-year-old male who developed severe pulmonary dysfunction after severe head injury in a high-velocity car accident. Chest X-ray showed bilateral diffuse patchy infiltrates. Pneumothorax, haemothorax, pulmonary aspiration, various forms of pulmonary oedema and pulmonary contusion could be excluded. Furthermore, there was an open laceration of the frontal sinus and maxillo-facial fractures. The history of spontaneous respiration in sitting position at the scene, rapid improvement of pulmonary function within 30 h, small amounts of air in the brain parenchyma, and circulatory shock despite elevated central venous pressure in the initial phase led to the diagnosis of PAE as the primary cause of pulmonary dysfunction. The diagnostic approach and basic therapeutical principles in patients with PAE are described. In conclusion, the case presented emphasizes the importance of considering PAE as a possible cause of respiratory failure in patients with severe head injury.

Accidents, Traffic↗

Current recommendations for neurotrauma.

Diagnostic and monitoring procedures for patients with head injury are aimed at early detection of mass lesions and secondary insults. Our therapeutic approach is based on our understanding of pathophysiologic mechanisms that cause secondary brain damage, and includes evacuation of mass lesions and prevention of secondary insults. Basic research has greatly increased our knowledge of these pathophysiologic mechanisms and has prompted the development of many neuroprotective agents, targeted to selected mechanisms. Unfortunately, it has proved difficult to demonstrate the benefit of such agents in the overall population of head-injured patients. Clinical research has emphasized the importance of ischemia in head injury and has demonstrated the deleterious effect of secondary insults on outcome. Medical management of patients with head injury has consequently focused on prevention of secondary insults, treatment of raised intracranial pressure, and maintenance of adequate cerebral perfusion pressure. The introduction of new monitoring techniques in head-injured patients offers the possibilities of more targeted therapy in individual patients, in contrast to the current practice of a staircase approach to treatment of raised intracranial pressure.In the US, an evidence-based approach has resulted in the wide acceptance of general principles, but at the same time highlighted the lack of hard evidence for the use of many therapeutic modalities. Practical guidelines, developed and published by the European Brain Injury Consortium, are based on expert opinion and consensus. Surveys have shown considerable variation in monitoring techniques and treatment. There is still considerable need for further improvements, both from a medical scientific perspective and from an organizational aspect. Particularly relevant are early resuscitation and stabilization at the scene of the accident, the organization of emergency services, admission policy to the intensive care unit, and improved policy for early identification of patients with operable intracranial hematoma. Further dissemination and general acceptance of already published guidelines may be expected to significantly improve care in head injury.

Journal Article↗

Selective neck occlusion of a large complex aneurysm of the middle cerebral artery trifurcation with the UltraSoft coil.

We present a case of an unruptured, large, complex, middle cerebral artery trifurcation aneurysm that was successfully treated by selective occlusion of the neck with a single, newly available UltraSoft coil. The satisfactory initial anatomic result was stable, as demonstrated on a 3-month follow-up arteriogram that indicated complete anatomic cure. The novel UltraSoft coil offers additional possibilities in the endovascular management of difficult-to-treat vascular lesions.

Adult↗

Uniform MDM2 overexpression in a panel of glioblastoma multiforme cell lines with divergent EGFR and p53 expression status.

BACKGROUND: Overexpression and deletion mutation of the epidermal growth factor receptor (EGFR) gene, as well as murine double minute 2 (MDM2) overexpression have been linked to the absence of p53 gene mutations in human glioblastoma multiforme (GBM). MATERIALS AND METHODS: EGFR and MDM2 messenger (m)RNA expression profiles and p53 status were examined by reverse transcription-polymerase chain rection (RT-PCR) and gene sequencing, respectively, in a set of human wild-type (wt) p53 GBM cell lines (U-87MG, U-87MG.wtEGFR and U-87MG.deltaEGFR) that exclusively differ in EGFR expression (endogenous wt EGFR expression, exogenous wt EGFR overexpression and exogenous 801-bp deletion-mutant [delta] EGFR overexpression, respectively), as well as in two human mutant p53 GBM cell lines that differ approximately two-fold in endogenous wt EGFR mRNA expression. RESULTS: Regardless of the underlying heterogeneity in EGFR mRNA expression and p53 status, MDM2 was similarly overexpressed among the cell lines. CONCLUSION: These data suggest that in human GBM (i) overexpression of wt or deltaEGFR and of MDM2 may constitute independent genetic events, (ii) overexpression of wt EGFR and mutation of p53 in GBM, although considered mutually exclusive in vivo, are not reciprocally prohibitive per se, and (iii) p53 mutations do not necessarily preclude MDM2 overexpression. In addition, this set of human GBM cell lines may constitute a suitable model for evaluating MDM2-targeted therapies in the context of various accompanying genetic alterations.

Brain Neoplasms↗