Technical report: surgical preparation of human brain tissue for clinical and basic research

BACKGROUND

The study of the distinct structure and function of the human central nervous system, both in healthy and diseased states, is becoming increasingly significant in the field of neuroscience. Typically, cortical and subcortical tissue is discarded during surgeries for tumors and epilepsy. Yet, there is a strong encouragement to utilize this tissue for clinical and basic research in humans. Here, we describe the technical aspects of the microdissection and immediate handling of viable human cortical access tissue for basic and clinical research, highlighting the measures needed to be taken in the operating room to ensure standardized procedures and optimal experimental results.

METHODS

In multiple rounds of experiments (n = 36), we developed and refined surgical principles for the removal of cortical access tissue. The specimens were immediately immersed in cold carbogenated N-methyl-D-glucamine-based artificial cerebrospinal fluid for electrophysiology and electron microscopy experiments or specialized hibernation medium for organotypic slice cultures.

RESULTS

The surgical principles of brain tissue microdissection were (1) rapid preparation (<1 min), (2) maintenance of the cortical axis, (3) minimization of mechanical trauma to sample, (4) use of pointed scalpel blade, (5) avoidance of cauterization and blunt preparation, (6) constant irrigation, and (7) retrieval of the sample without the use of forceps or suction. After a single round of introduction to these principles, multiple surgeons adopted the technique for samples with a minimal dimension of 5 mm spanning all cortical layers and subcortical white matter. Small samples (5-7 mm) were ideal for acute slice preparation and electrophysiology. No adverse events from sample resection were observed.

CONCLUSION

The microdissection technique of human cortical access tissue is safe and easily adoptable into the routine of neurosurgical procedures. The standardized and reliable surgical extraction of human brain tissue lays the foundation for human-to-human translational research on human brain tissue.

[Traumatology-an interdisciplinary task: exclusively for educational purposes?]

BACKGROUND

Traumatology of the head and neck region is not only a part of otorhinolaryngology, but also has a large overlap with neighboring disciplines of the head and neck region. In Freiburg, an interdisciplinary lecture on "ENT emergencies" was implemented in the 21/22 winter semester. The aim was to provide an even more realistic view on interdisciplinary patient care and to make evident the areas of intersection of four of the major head disciplines (otorhinolaryngology, neurosurgery, ophthalmology, and maxillofacial surgery).

MATERIALS AND METHODS

A new, special lecture in otorhinolaryngology was implemented as part of the regular online lecture series accompanying the semester. With reference to the clinical care of ENT emergencies, possible overlaps with neighboring disciplines were identified and explained by the discipline representatives or discussed in front of and with the auditorium. At the end of the semester, all participating students (n = 173) were invited to evaluate the seminar using the survey tool "EvaSys" (EvaSys GmbH, Lüneburg, Germany). In total, 78 students participated in the evaluation process.

RESULTS

The new lecture concept was very well accepted and immediately ranked top among the interdisciplinary lecture titles within the ENT lecture series. The clear communication of the term "interdisciplinarity" in the sense of a complementary clinical cooperation was also very successful and was appreciated accordingly by students during the evaluation process.

CONCLUSION

Pragmatic presentation of ideal clinical patient care using an interdisciplinary approach is possible within the regular ENT lecture series. This realistic portrayal, beyond any technical and/or professional differences, is of great interest to students and is considered clinically relevant. Thus, interdisciplinary lectures provide a valuable tool to teach the fundamental values of clinical interdisciplinary management for the best possible patient care.

Measures of insulin resistance as a screening tool for dysglycaemia in patients with coronary artery disease. A report from the EUROASPIRE V population

Background

The optimal screening strategy for dysglycaemia, including type 2 diabetes (T2DM) and impaired glucose tolerance (IGT), in patients with coronary artery disease (CAD) is debated.

Purpose

We tested the hypothesis that measures of insulin resistance by homeostasis model assessment (HOMA) indexes may constitute accurate screening methods in a CAD population.

Methods

Insulin, C-peptide, glycated haemoglobin A1c (HbA1c) and an oral glucose tolerance test (OGTT) were centrally assessed in 3534 CAD patients without known dysglycaemia from the EUROASPIRE V survey. Three different HOMA indexes were calculated: HOMA-IR, HOMA2 based on insulin (HOMA2-ins), and HOMA2 based on C-peptide (HOMA2-Cpep). Dysglycaemia was diagnosed based on the two-hour postload glucose (2hPG) value obtained from the OGTT. Information on study participants was obtained by standardised visits. The optimal thresholds of the three HOMA indexes for dysglycaemia diagnosis were obtained by the maximum value of Youden's J statistic on receiver operator characteristics curves. The diagnostic performance of such thresholds was tested for both T2DM (i.e. in reference to a 2hPG value ≥11 mmol/L) and dysglycaemia (i.e. in reference to 2hPG value ≥7.8 mmol/L) and their correlation with several clinical parameters was assessed by Spearman's coefficients.

Results

The mean age of the patients was 63 years and 25% were women. Fifty-four percent of the patients had central obesity, 18% were current smokers, mean blood pressure was 133/80 mmHg and mean LDL-cholesterol 2.4 mmol/L. The OGTT revealed that 41% were dysglycaemic (IGT = 24% and T2DM = 16%). Mean insulin, C-peptide and HOMA indexes were significantly higher in patients with vs. without newly detected dysglycaemia (all p&lt;0.0001). Sensitivity and specificity of the three HOMA indexes for the diagnosis of dysglycaemia were low and the associations between 2hPG and the other parameters in the total sample were weak, with Spearman correlation coefficients of 0.15 for fasting insulin, 0.19 for C-peptide, 0.24 for HOMA-IR, 0.18 for HOMA2-ins and 0.22 for HOMA2-Cpep. HOMA-IR, HOMA2-ins and C-peptide were strongly correlated with body mass index and waist circumference (Spearman correlation coefficients ranging 0.43–0.47).

Conclusion

Screening for dysglycaemia in CAD patients by insulin, C-peptide, HOMA-IR, HOMA2-ins and HOMA2-Cpep had insufficient diagnostic performance to detect dysglycaemia with reference to the yield of an OGTT, which should still be prioritized. Further studies are warranted to assess whether measures of insulin resistance might be better markers of unfavourable metabolic derangement beyond dysglycaemia.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): European Society of CardiologyErling-Perssons Stiftelse

P10.24.A A personalized BRAF mutant glioblastoma with Human2Humanex-vivo cortical cultures

Background

Glioblastoma is among the most common primary malignancy with a poor medium survival post-diagnosis. The incredible heterogeneity of glioblastoma highlights its incurable nature. Methods to overcome difficulties leaded by glioblastoma heterogeneity remain to be explored. Here we present our Human2Human personalized autografted BRAF(V600E) mutant glioblastoma model, focusing on the idea of precision. This model, with an inoculation of self-derived glioblastoma cells, can imitate the tumor growth, invasion, metabolism and microenvironmental crosstalk within its “native” microenvironment and allows us to investigate the influence of different chemotherapies on the immunosuppressive tumor microenvironment from each specific individual glioblastoma patient.

Material and Methods

Non-neoplastic cortical tissue was obtained from a BRAF(V600E) mutant glioblastoma patient during surgical operation. Tissue was sectioned and inoculated with autografted glioblastoma cells in order to establish the ex-vivo Human2Human personalized brain slice model. Slice viability and tumor growth were monitored throughout the culture period, with and without day-wise refreshed treatments of clinically proved BRAF/MEK inhibitors. Sections were fixed and stained post cultivation. Pathway proteins p-ERK, p-Akt based on BRAF signaling along with markers (TMEM119, Iba-1, CD3, CD68, GFAP and NeuN) for major cell types in the environment were stained. Single Nuclei RNA Sequencing and Spatially Resolved Transcriptomics were applied.

Results

Tumor growth quantification over the culture period revealed different tumor reaction and tolerance towards various chemotherapies. The combination of Vemurafenib + Trametinib exhibited more efficient therapy response in comparison with either Dabrafenib + Trametinib or Encorafenib + Trametinib. Immunofluorescence and immunohistochemistry based quantification referring to neurons (NeuN), astrocytes (GFAP) and microglia/macrophage cells (Iba-1) suggested no toxic effects of the drug combinations on the tumor microenvironment. BRAF pathway proteins and immune cells showed various activation patterns upon different treatment combinations on an immunofluorescence base. Single Nuclei RNA Sequencing revealed the mesenchymal differentiation of BRAF mutant glioblastoma cells. Spatially Resolved Transcriptomics characterized tumor recurrence and suggested the therapy response accurately and visually.

Conclusion

The combination of Vemurafenib + Trametinib shows strategy to this specific BRAF mutant glioblastoma patient. And therefore, this Human2Human personalized model has a potential to provide in-depth information of the spatio-temporal tumor differentiation ex-vivo, correct inter-patient bias, and model therapy response in a very short time frame to provide drug testing results for clinical decision making.

P12.14.A The role of onco-metabolite (R2hydroxyglutarate) in the IDH mutant glioblastoma microenvironment

Background

Recently, we found that the reactive astrocytes in the IDH wild type glioblastoma contribute to anti-tumor immunity and support pro-oncogenic signaling. Here, we characterized the transcriptomic signature of IDH1/2-mutant glioma associated astrocytes and determined a unique inflammatory transformation, profoundly different to astrocytes in IDH wildtype glioma patients due to an onco-metabolite R-2-hydroxyglutarate using Next generation sequencing and human ex-vivo slice model.

Material and Methods

We purified and transcriptionally profiled astrocytes from 9 patients with confirmed IDH1-R132H mutation, by means of RNA-sequencing and the data were analyzed using the established pipelines. We also used spatial transcriptomics to evidently show the spatial distribution of astrocytes in IDH-mutated/wildtype glioma samples. We validated our findings using human organotypic slice model inoculated with IDH-mutant cell line or treated with oncometabolite 2-hydroxy glutarate. Additionally, LC-MS was further used to give us a chart of neurotransmitters due to altered microenvironment.

Results

Our results from RNA sequencing showed a transcriptional transformation of reactive astrocytes within the microenvironment of IDH-mutated tumors compared to wildtype glioma by means of RNA-sequencing of purified astrocytes. And, using our established human neocortical GBM model inoculated with IDH mutant tumor and R-2HG treatment, we showed that we were able to activate inflammatory transcriptional programs in astrocytes, mediated by the presence of microglia. Further, by spatially mapping the transcriptomic profiles of purified microglia, we were able to confirm that microglia also demonstrate inflammatory activation in IDH mutated glioma. This inflammatory astrocyte transformation is associated with a loss of neurotransmitter homeostasis (disrupted levels of glutamate) in the treated sections, as has been previously reported in IDH mutated tumors. Additionally, R-H2G increased neuronal spiking rate in, pointing to potential excitotoxicity.

Conclusion

Our work provides a crucial contribution towards understanding the role of R-2HG in the IDH mutant glioma microenvironment and sheds light on the significant microenvironmental differences to IDH wild-type glioma.

Longitudinal stability of molecular alterations and drug response profiles in tumor spheroid cell lines enables reproducible analyses

The utility of patient-derived tumor cell lines as experimental models for glioblastoma has been challenged by limited representation of the in vivo tumor biology and low clinical translatability. Here, we report on longitudinal epigenetic and transcriptional profiling of seven glioblastoma spheroid cell line models cultured over an extended period. Molecular profiles were associated with drug response data obtained for 231 clinically used drugs. We show that the glioblastoma spheroid models remained molecularly stable and displayed reproducible drug responses over prolonged culture times of 30 in vitro passages. Integration of gene expression and drug response data identified predictive gene signatures linked to sensitivity to specific drugs, indicating the potential of gene expression-based prediction of glioblastoma therapy response. Our data thus empowers glioblastoma spheroid disease modeling as a useful preclinical assay that may uncover novel therapeutic vulnerabilities and associated molecular alterations.

OS06.9A Diversity of cellular communication in glioblastoma

BACKGROUND

Owing to recent advances in understanding of the active functional states exhibited within glioblastoma (GBM), intra-tumoral cellular signaling has moved into focus of neuro-oncological research. In our study, we aim to explore the diversity of transcellular signaling and investigate correlations to transcriptional dynamics and cellular behavior.

MATERIAL AND METHODS

Electrophysiological mapping of primary GBM cultures was performed by planar microelectrodes, in conjunction with calcium imaging in a human neocortical section based GBM model. Exposure to conditions that are physiologically present within the tumor was carried out to identify specific signaling cells of interest and signaling diversity presented as response to specific environmental conditions. Transcriptional dynamics and plasticity were examined by means of scRNA-sequencing with CRISPR based perturbation, spatial transcriptomics and deep long-read RNA-sequencing.

RESULTS

Electrophysiological profiles of primary GBM cell lines revealed highly variable network activity. Despite these different characteristics, all profiled primary cell-lines exhibited characteristics of scale-free networks, confirmed in a human neocortical GBM model. When the GBM was allowed to grow in “in-vivo” like environment, basal activity was significantly increased, owing to interactions with elements within the neural environment. Cellular signaling was directly correlated to changes in the environment, like hypoxia or glutamatergic activation, and total inhibition of electrical signaling was achieved only with a combination of both gap junction and synaptic inhibitors. Using single-cell sequencing and proteomics, we identified several genes related to synaptogenesis that plays a crucial role in network formation and consequently transcellular signaling. CRISPR based perturbation of these genes resulted in alterations in cellular morphology and decreased cellular connectivity, with electrical signaling being significantly attenuated. Single-cell sequencing of perturbed tumor cells in the GBM model revealed a loss of developmental lineages and significant reduction of cellular stress response state.

CONCLUSION

Our findings highlight the role of electrical signaling in glioblastoma. Cellular stressors induce intercellular signaling, leading to transcriptional adaptation suggesting that there exists a highly complex and powerful mechanism for dynamic transcriptional state adaptation.

Risk and management of pre-diabetes

Type 2 diabetes mellitus (T2DM) is associated with a two- to four-fold increased risk of developing cardiovascular disease (CVD) and microvascular complications, which may already be present before diagnosis. It is, therefore, important to detect people with an increased risk of T2DM at an early stage. In order to identify individuals with so-called 'pre-diabetes', comprising impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), current guidelines have developed definitions based on fasting plasma glucose, two-hour glucose concentrations and haemoglobin A1c. Subjects with pre-diabetes are at an increased risk of developing T2DM and CVD. This elevated risk seems similar according to the different criteria used to define pre-diabetes. The risk of progression to T2DM or CVD does, however, depend on other risk factors such as sex, body mass index and ethnicity. Based on the risk factors to develop T2DM, many risk assessment models have been developed to identify those at highest risk. These models perform well to identify those at risk and could be used to initiate preventive interventions. Many studies have shown that lifestyle modification and metformin are effective in preventing the development of T2DM, although lifestyle modification seems to have a more sustainable effect. In addition, lifestyle modification seems more effective in those with IGT than those with IFG. In this review, we will describe the different definitions used to define pre-diabetes, progression from pre-diabetes to T2DM or other vascular complications, risk factors associated with progressions and the management of progression to T2DM, ending with clinical recommendations.

P11.58 Astrocytic Environment Aid the Evolution of Immunosuppressive Environment in Glioblastoma

BACKGROUND

Glioblastomas are referred to as immunologically “cold” tumors since their cellular environment promotes an anti-inflammatory environment leading to an unresolved barrier to immunotherapy. Although the role of reactive astrocytes in other inflammatory diseases has been investigated in several studies, the immunoregulatory functions of astrocytes in the tumor environment remains poorly understood.

MATERIAL AND METHODS

We purified reactive astrocytes from de-novo glioblastoma and non-infiltrated cortex specimens by immunoprecipitation and analyzed the transcriptional phenotype by RNA sequencing. In order to investigate the origin of astrocytic transformation, we used a microglia loss-of-function model in human organotypic slices. Microglia was depleted by clodronat stimulation. We injected tumor cells and analyzed gene expression of the astrocytes after 7d incubation by RNA sequencing. Environmental cytokines were analyzed by multi-ELISA. Immunostainings of slices were processed by confocal microscopy and 3D reconstruction.

RESULTS

Here we address the immunological impact of tumor-associated astrocytes, we were able to identify a novel reactive subtype marked by JAK/STAT pathway activation and CD274 expression. Our results show a distinct astrocytic transcriptional phenotype that mutually arises from both microglia and astrocytes of the tumor environment. This interaction leads to a large release of anti-inflammatory cytokines such as TGFß and IL10. The reactive subtype switch of astrocytes was recovered by inhibition of the JAK pathway, which caused an increase of pro-inflammatory environment.

CONCLUSION

Our results can form the basis for a novel therapeutic approach by directly targeting tumor-associated astrocytes in order to transformimmunologically “cold” into “warm” tumors.

[PET-MR in patients with glioblastoma multiforme]

Glioblastoma multiforme (GBM) is the most common and most aggressive primary tumor of the brain. In recent years newer therapeutic approaches have been developed. To allow for an optimized treatment planning it is important to precisely delineate necrotic tissue, edema and vital tumor tissue and to identify the most aggressive parts of the GBM. The magnetic resonance (MR) portion of an MR-positron emission tomography (PET) examination in patients with GBM should consist of both structural and functional sequences including diffusion-weighted and perfusion sequences. The use of (18)F-fluorodeoxyglucose ((18)F-FDG) is limited in patients with gliomas as glucose metabolism is already physiologically high in parts of the brain but (18)F-FDG is nevertheless a commonly used radiopharmaceutical for neuro-oncological questions. (18)F-fluorothymidine reflects the cellular activity of thymidine kinase 1 and correlates with the expression of KI-67 as an index of mitotic activity. The nitroimidazole derivatives (18)F-fluoromisonidazole and (18)F-fluoroazomycin arabinoside ((18)F-FAZA) allow the detection of hypoxic areas within the tumor. In recent years amino acid tracers, such as (18)F-fluoroethyltyrosine are increasingly being used in the diagnosis of gliomas. The simultaneous PET-MR image acquisition allows new approaches, e.g. motion correction by the simultaneous acquisition of MR data with a high temporal resolution and an improved quantification of the PET signal by integrating the results of functional MR sequences. Moreover, the simultaneous acquisition of these two time-consuming methods leads to reduced imaging times for this, often severely ill patient group.

Acarbose improves glycemic control and reduces body weight: Subanalysis data of South Asia region

Alpha-glucosidase inhibitors (AGIs) are widely used especially in Asian countries as a treatment option for type 2 diabetes patients with high postprandial glycaemia. However, data from South Asia region is very limited. In order to examine the effect of AGI in real-life setting, 10 PMS/NIS from all over the world from the launch of acarbose to date were pooled in one database and exploratory analysis was performed for glycemic parameters and weight. In total 62,905 patients were pooled from 21 countries and regions. Mean follow up (± SD) was 12.2 ± 4.8 weeks (range 0.1-108.9). From South Asia region (India and Pakistan), 8,738 Asian patients were enrolled. Mean PPG decreased from 240.0 and 261.1 mg/dl at baseline by 70.26 ± 65.10 and 82.96 ± 56.59 mg/dl at the last visit in total and South Asian populations, respectively (n = 53,883; n = 7,991, P < 0.0001 for both). Mean FPG decreased from 171.6 and 176.5 mg/dl at baseline by 38.48 ± 47.83 and 49.59 ± 41.41 mg/dl at the last visit in total and South Asian populations, respectively (n = 56,672; n = 7,837, P < 0.0001 for both). Mean HbA1c decreased from 8.4 and 8.4% at baseline by 1.11 ± 1.31% and 0.91 ± 0.93% at the last visit in total and South Asian populations, respectively (n = 38,843; n = 2,343, P < 0.0001 for both). Mean relative reduction of body weight (BW) was 1.40 ± 3.28% and 1.10 ± 3.39% at the last visit for mean baseline BW 73.6 and 74.2 kg in total and South Asian populations, respectively (n = 54,760; n = 7,718, P < 0.0001 for both). Consistent with RCT meta-analyses, post-hoc analysis of real-life data showed acarbose treatment improved glycaemic control and reduced the BW. Acarbose treatment in real life setting showed significant reductions in all glycemic parameters and BW in Asian patients from South Asia region.

Alpha-glucosidase inhibitor, acarbose, improves glycamic control and reduces body weight in type 2 diabetes: Findings on indian patients from the pooled data analysis

Alpha-glucosidase inhibitors are widely used especially in Asian countries as a treatment option for type 2 diabetes patients with high postprandial glycemia (PPG). The higher carbohydrate in the Indian diets lead to greater prandial glycemic excursion, increased glucosidase, and incretin activity in the gut and may need special therapeutic strategies to tackle these glucose peaks. This is the subgroup analysis of Indian subjects who participated in the GlucoVIP study that investigated the effectiveness and tolerability of acarbose as add-on or monotherapy in a range of patients with type 2 diabetes mellitus. A total of 1996 Indian patients were included in the effectiveness analysis. After 12.5 weeks (mean), the mean change in 2-hour PPG from baseline was -74.4 mg/dl, mean HbA1c decreased by -1.0%, and mean fasting blood glucose decreased by -37.9 mg/dl. The efficacy of acarbose was rated "very good" or "good" in 91.1% of patients, and tolerability as "very good" or "good" in 88.0% of patients. The results of this observational study suggest that acarbose was effective and well tolerated in the Indian patients with T2DM.

A simple new non-invasive sweat indicator test for the diagnosis of diabetic neuropathy

A simple non-invasive indicator test (Neuropad(®)) has been developed for the assessment of sweating and, hence, cholinergic innervation in the diabetic foot. The present review summarizes current knowledge on this diagnostic test. The diagnostic ability of this test is based on a colour change from blue to pink at 10 min, with excellent reproducibility, which lends itself to patient self-examination. It has a high sensitivity (65.1-100%) and negative predictive value (63-100%), with moderate specificity (32-78.5%) and positive predictive value (23.3-93.2%) for the diagnosis of diabetic peripheral neuropathy. It also has moderate to high sensitivity (59.1-89%) and negative predictive value (64.7-91%), but low to moderate specificity (27-78%) and positive predictive value (24-48.6%) for the diagnosis of diabetic cardiac autonomic neuropathy. There are some data to suggest that Neuropad can detect early diabetic neuropathy, but this needs further evaluation. It remains to be established whether this test can predict foot ulceration and amputation, thereby contributing to the identification of high-risk patients.

Personalized surgical therapy

Gliomas are more or less diffuse tumours with the ability to infiltrate surrounding functional brain tissue. Thus, curative surgical treatment generally cannot be achieved. Despite these limitations, open tumour resection represents one of the mainstays in glioma treatment settings. Beyond tissue sampling for accurate histological and molecular genetic evaluation, decompressive effects in the case of space occupying tumours and oncologically relevant cytoreductive effects of microsurgery have been reported in selected patients with glioma of different grades. This paper provides practical considerations in order to integrate the concept of a personalized surgical therapy into the prognostic network of low- and high-grade gliomas, covering both microsurgery and stereotactic biopsy techniques.

Insulin and atherosclerosis: how are they related?

The relationship between insulin and atherosclerosis is complex. People with type 2 diabetes are affected by three main glycaemic disorders: chronic hyperglycaemia; glycaemic variability; and iatrogenic hypoglycaemia. In addition to this triumvirate, the diabetic condition is characterized by lipid disorders, chronic low-grade inflammation and activation of oxidative stress. All these associated disorders reflect the insulin-resistant nature of type 2 diabetes and contribute to the development and progression of cardiovascular (CV) diseases. By both lowering plasma glucose and improving the lipid profile, insulin exerts beneficial effects on CV outcomes. In addition, insulin has several pleiotropic effects such as anti-inflammatory, antithrombotic and antioxidant properties. Insulin per se exerts an inhibitory effect on the activation of oxidative stress and seems able to counteract the pro-oxidant effects of ambient hyperglycaemia and glycaemic variability. However, insulin actions remain a subject of debate with respect to the risk of adverse CV events, which can increase in individuals exposed to high insulin doses. Evidence from the large-scale, long-term ORIGIN trial suggests that early implementation of insulin supplementation therapy in the course of glycaemic disorders, including type 2 diabetes, has a neutral impact on CV outcomes compared with standard management. Thus, the answer to the question "What impact does insulin have on atherosclerosis?" remains unclear, even though it is logical to deduce that insulin should be initiated as soon as possible and that small doses of insulin early on are better than higher doses later in the disease process.

Oral glucose tolerance test and HbA₁c for diagnosis of diabetes in patients undergoing coronary angiography: [corrected] the Silent Diabetes Study

AIMS/HYPOTHESIS

The primary aim of this study was to compare the results of HbA(1c) measurements with those of an OGTT for early diagnosis of 'silent diabetes' in patients with coronary artery disease (CAD) undergoing angiography without prediagnosed diabetes. A secondary aim was to investigate the correlation between the extent of CAD and the glycaemic status of the patient.

METHODS

Data from 1,015 patients admitted for acute (n = 149) or elective (n = 866) coronary angiography were analysed. Patients with known diabetes were excluded from the study. Using the OGTT results, patients were classified as having normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or diabetes. According to the results of the HbA(1c) measurements, patients were classified into three groups: normal (HbA(1c) <5.7% [<39 mmol/mol]), borderline (HbA(1c) 5.7-6.4% [39-47 mmol/mol]) and diabetes (HbA(1c) ≥6.5% [≥48 mmol/mol]).

RESULTS

Based on the OGTT, 513 patients (51%) were classified with NGT, 10 (1%) with IFG, 349 (34%) with IGT and 149 (14%) were diagnosed with diabetes. According to HbA(1c) measurements, 588 patients (58%) were classified as normal, 385 (38%) as borderline and 42 (4%) were diagnosed with diabetes. The proportion of patients with IGT and diabetes increased with the extent of CAD (IGT ρ = 0.14, p < 0.001, diabetes ρ = 0.09, p = 0.01). No differences in HbA(1c) were seen among the groups with different extents of CAD (p = 0.652).

CONCLUSIONS/INTERPRETATION

An OGTT should be performed routinely for diagnosis of diabetes in patients with CAD undergoing coronary angiography, since HbA(1c) measurement alone appears to miss a substantial proportion of patients with silent diabetes. A limitation of the study is that the OGTT was not performed before the angiography.

[Challenge in diabetes therapy: effects of glitazones beyond blood glucose control]

Not just since the results of ACCORD, ADVANCE and VADT were published, it is clear that lowering blood glucose alone does not reduce the cardiovascular risk of patients with type 2 diabetes. In fact, many studies also indicate that some treatment strategies may even have adverse effects. To treat type 2 diabetes appropriately, the co-morbidities such as diabetic dyslipidaemia, hypertension or nephropathy must also be taken into account. Thiazolidinediones reduce insulin resistance thus allowing to direct the treatment of type 2 diabetes towards its pathophysiologic origin. Due to their mechanism of action, thiazolidinediones not only lower blood glucose but have also beneficial effects on inflammatory and atherogenic parameters, blood pressure and microalbuminuria. Furthermore pioglitazone improves dyslipidaemia and reduces mortality, myocardial infarction and stroke in high risk patients. Effects of rosiglitazone on the cardiovascular risk are yet unclear. Numerous studies document the efficacy and safety of thiazolidinediones and provide a basis for an evidence-based therapeutic approach beyond blood glucose control.

Surgical resection plus stereotactic 125I brachytherapy in adult patients with eloquently located supratentorial WHO grade II glioma - feasibility and outcome of a combined local treatment concept

OBJECTIVE

The current pilot study analyzed feasibility, risk and effectiveness of 1) microsurgery plus stereotactic iodine-125 ((125)I) brachytherapy (SBT) for large (diameter > 4 cm), circumscribed, and complex located WHO grade II glioma and 2) SBT alone for small (diameter < 4 cm), and complex located recurrences.

METHODS

Lowactivity temporary (125)I seeds were used. The applied reference dose was 54 Gy and the dose rate was low (median, 10 cGy/h). Time to progression and time to additional external beam radiation (EBR) and/or chemotherapy were estimated with the Kaplan-Meier method. Any adverse sequel potentially attributable to treatment was classified as morbidity. Treatment effects of SBT were estimated according to the modified MacDonald criteria.

RESULTS

Thirtyone patients (de novo group: n = 18, recurrence group: n = 13) were included. The median tumor volume before surgery was 66 ml. A planned partial tumor resection achieved eligibility for SBT in all patients. Transient morbidity of microsurgery and SBT was 27.8 % and 6.4 %, respectively. There was no permanent morbidity. Radiogenic complications did not occur. Complete response, partial response, and stable disease were seen in 8, 9, and 14 patients, respectively. Ten patients exhibited tumor progression (overall 5-year progression- free survival > 60 %). The 5-year probability to receive chemotherapy and/or EBR was 18 %.

CONCLUSION

A planned partial tumor resection of large and complex located WHO grade II glioma is safe. SBT of small and complex located residual of recurrent tumors is safe and minimally invasive. Combined treatment may provide the possibility to withhold EBR and/or chemotherapy for a considerable number of patients and deserves further prospective evaluation.

[Glucose control in cardiac disease]

The early and differentiated optimization of glucose level is essential for the improvement of the cardiovascular outcome. In all stages of cardiac disease, the primary goal is to reach near-normoglycemia. The DIGAMI-1 and 2 studies as well as the Munich Myocardial Infarction Registry successfully demonstrate, that the intensification of treatment with insulin therapy reduces the mortality of myocardial infarction. Glucose-insulin-infusion is advantageous with regard to the use of a well-controllable therapeutic approach. In non-acute cardiac disease, oral treatment strategies and insulin therapy are successful alone or in combination. Acarbose and metformin have been shown to be able to successfully prevent cardiovascular disease. New evidence of positive effects of glitazones with regard to reduction of the rate of restenosis and optimization of endothelial function is currently emerging. Prognosis of cardiovascular disease is significantly influenced by glucose control. There is evidence that the relationship between glycemia and cardiovascular events extends far beyond the diabetic threshold. This can be detected even in impaired glucose tolerance and the non-diabetic range. There is evidence that postprandial glycemia is crucial for the extent of cardiovascular risk. This has also been emphasized by the DECODE-study.

Acarbose and metabolic control in patients with type 2 diabetes with newly initiated insulin therapy

AIM

This study was designed to investigate the effect of acarbose in patients with type 2 diabetes with newly initiated insulin treatment who had previously been insufficiently controlled with oral antihyperglycaemic agents [haemoglobin A(1c) (HbA(1c)) >/= 8%].

METHODS

In this 20-week double-blind, placebo-controlled study, 163 patients were randomized to receive acarbose up to 100 mg three times a day or matching placebo. Both the groups were newly initiated with insulin, which was adjusted according to blood glucose values. Primary efficacy parameter was the change in HbA(1c) from baseline; changes in daily insulin doses were also assessed.

RESULTS

Mean HbA(1c) was significantly reduced by acarbose compared with placebo (2.31 vs. 1.81%, p = 0.033). Insulin doses were comparable at the end of the study. There was no difference in blood glucose and triglyceride levels between the treatment groups. Postprandial serum insulin levels increased in both treatment arms owing to insulin administration but less so under acarbose. In contrast to the placebo group, an increase in body mass index was prevented for acarbose-treated patients.

CONCLUSION

As adjunct administration to newly initiated insulin therapy, acarbose enhances the optimization of blood glucose control in patients with type 2 diabetes.

Chromium in metabolic and cardiovascular disease

Chromium is an essential mineral that appears to have a beneficial role in the regulation of insulin action, metabolic syndrome, and cardiovascular disease. There is growing evidence that chromium may facilitate insulin signaling and chromium supplementation therefore may improve systemic insulin sensitivity. Tissue chromium levels of subjects with diabetes are lower than those of normal control subjects, and a correlation exists between low circulating levels of chromium and the incidence of type 2 diabetes. Controversy still exists as to the need for chromium supplementation. However, supplementation with chromium picolinate, a stable and highly bioavailable form of chromium, has been shown to reduce insulin resistance and to help reduce the risk of cardiovascular disease and type 2 diabetes. Since chromium supplementation is a safe treatment, further research is necessary to resolve the confounding data. The existing data suggest to concentrate future studies on certain forms as chromium picolinate and doses as at least 200 mcg per day.