New concept in neurovascular navigation: technical description and preclinical experience with the Bendit 17 and Bendit 21 microcatheters in a rabbit aneurysm model

BACKGROUND

Endovascular treatment of intracranial vascular diseases, such as aneurysms, is often challenged by unfavorable vascular anatomy. The Bendit Steerable Microcatheter (Bendit Technologies, Tel Aviv, Israel) has bending and torqueing capabilities designed to improve navigation and stability during device delivery, with or without a guidewire. We describe our preclinical experience with the Bendit 17 and Bendit 21 microcatheters in a rabbit aneurysm model.

METHODS

Bifurcation and side wall aneurysms were created surgically in six New Zealand rabbits. We attempted to navigate Bendit devices through the vasculature and enter the aneurysms without a guidewire. Various positions within the aneurysm were selectively explored. Angiographic imaging was used to visualize catheterization, navigation, vascular manipulations, and placement of coils, stents, and intrasaccular devices.

RESULTS

We successfully navigated the Bendit microcatheters to all aneurysms without a guidewire. We successfully recanalized a nearly occluded carotid artery and navigated the Bendit through a braided stent. In contrast, we were unable to navigate a comparator device with a guidewire as effectively as the Bendit. Coils were introduced at different locations within the aneurysm and could be pushed, pulled, and repositioned with the Bendit tip. Finally, we used the Bendit to deliver intrasaccular devices designed for terminal aneurysms to treat side wall aneurysms.

CONCLUSIONS

Bendit's bending and torqueing abilities, combined with its stability in the bent position, enable quick navigation and optimal deployment of devices. Clinical studies are necessary to determine whether these navigation advantages lead to more efficient treatment of intracranial and peripheral aneurysms.

Evaluation of a novel flow diverter, the DiVeRt system, in an animal model

BACKGROUND

Using a surgical aneurysm model, this study assessed the performance of a new flow diverter (FD), the DiVeRt, and evaluated the angiographic and histologic features at different periods after stent deployment.

METHODS

Fifteen New Zealand White rabbits were treated 3 days prior to intervention and until euthanization with dual antiplatelets. DiVeRt was implanted in bilateral carotid aneurysms (n=30) as well as in the aorta (n=15). The rate of technical success, assessment of aneurysm occlusion (measured by the O'Kelly-Marotta grading (OKM) scale), and stent patency were examined using angiography and histologic examinations in three groups at 1, 3, and 6 months follow-up (FU). In each FU group one control animal was included and treated with the XCalibur stent (n=3).

RESULTS

Overall, DiVeRt placement was successful and without apparent intraprocedural complications. In total, four stents in the carotid artery were occluded and in-stent stenosis was registered in two carotid (7%) and one aortic (6%) vessels. Complete or near complete aneurysm occlusion (OKM scale D1 and C3) was seen in 100% in the 1-month FU group, 70% in the 2-month FU group, and 100% in the 3-month FU group. Histology showed loose, organizing fibrous tissue matrix within the sac and adequate neck endothelialization in all vessels. All branches covered by the DiVeRt remained patent.

CONCLUSIONS

The DiVeRt system appears to be feasible and effective for the treatment of aneurysms with high rates of complete aneurysm occlusion, excellent vessel patency, and evidence of high biocompatibility. Occurrences of parent artery occlusion at follow-up did not result in clinical consequences.

Overcoming negative predictions of microRNA expressions to gemcitabine response with FOLFIRINOX in advanced pancreatic cancer patients

FOLFIRINOX is superior to gemcitabine in patients with pancreatic cancer, but this regimen is associated with toxicity and biomarkers for response are warranted. MicroRNAs can mediate drug resistance and could provide predictive information. Altered expressions of several microRNAs including miR-21-5p, miR-10b-5p and miR-34a-5p have been previously linked to a worse response to gemcitabine. We investigated the influence of expression levels in tumor tissue of those three microRNAs on outcome to FOLFIRINOX. Twenty-nine patients with sufficient formalin-fixed paraffin-embedded tumor tissue were identified. There was no significant association between high and low expression groups for these three microRNA. We conclude that polychemotherapy combination can overcome intrinsic negative prognostic factors.

Evaluation of circulating cell-free DNA as a molecular monitoring tool in patients with metastatic cancer

The clinical decisions made when treating patients with metastatic cancer require knowledge of the current tumor extent and response to therapy. For the majority of solid tumors, a response assessment, which is based on imaging, is used to guide these decisions. However, measuring serum protein biomarkers (i.e. tumor markers) may be of additional use. Furthermore, tumor markers exhibit variable specificity and sensitivity and cannot therefore be solely relied upon when making decisions regarding cancer treatment. Therefore, there is a clinical requirement for the identification of specific, sensitive and quantitative biomarkers. In recent years, circulating cell-free DNA (cfDNA) and mutation-specific circulating cell-free tumor DNA (cftDNA) have been identified as novel potential biomarkers. In the current study, cfDNA and cftDNA were compared using imaging-based staging and current tumor markers in 15 patients with metastatic colorectal, pancreatic or breast cancer. These patients were treated at the Third Medical Department of Paracelsus Medical University Salzburg (Austria). The results of the current study demonstrated a statistically significant correlation between the concentration changes of cfDNA and cftDNA and response to treatment, which was assessed by imaging. A correlation was not indicated with current clinically used tumor markers, including carcinoembryonic antigen, carcinoma antigen 15-3 and carcinoma antigen 19-9. The present study also indicated a correlation between cfDNA and cftDNA and the tumor volume of metastatic lesions, which was not observed with the current clinically used tumor markers. In conclusion, cfDNA and cftDNA exhibit the potential to become novel biomarkers for the response assessment following cancer treatment, and may serve as a tool for the estimation of tumor volume. The current study further supports the increasingly important role of cfDNA and cftDNA as new monitoring tools for use during cancer therapy.

Abstract P3-10-07: A 3-gene DNA methylation signature fails to predict response to bevacizumab in metastatic breast cancer patients treated within the TANIA phase III trial

Background: Biomarkers predicting response to bevacizumab containing therapy in metastatic breast cancer (MBC) are of urgent need. In a retrospective single-institution analysis we have previously shown that a 3-gene methylation signature (MLH1,POLKand TMBIM6) could discriminate between responders and non-responders to a bevacizumab-based therapy in two independent cohorts of patients with MBC with an AUC of 0.94 and 0.86, respectively (Gampenrieder SP et al. Theranostics. 2018. 8(8):2278-2288). Here, we present the validation of these findings within the prospective phase III trial TANIA (Vrdoljak E et al. Ann Oncol. 2016. 27(11):2046-52) randomizing 494 patients with HER2-negative MBC to chemotherapy plus bevacizumab or chemotherapy alone for two consecutive treatment lines (second- and third-line). All patients had already received bevacizumab-containing therapy in the first-line setting.

Patients and methods: DNA isolated from archival FFPE tumor samples was available from 200 patients consenting to optional translational research within the TANIA trial. Out of these, 176 samples were collected prior to first-line bevacizumab therapy and were analyzed retrospectively. Sufficient DNA for methylation analysis was available from 124 patients: 64 treated with chemotherapy plus bevacizumab and 60 treated with chemotherapy alone. All samples were isolated from the primary tumor. Quantitative methylation analysis was performed by pyrosequencing on the PyroMark Q24 Advanced System (Qiagen). PFS and OS analyses were performed in both study arms comparing “predicted responders” (PRED_R) versus “predicted non-responders” (PRED_NR) based either on median dichotomization or according to the cutoffs for individual CpG and the combined 3-CpG methylation logistic regression model.

Results:Out of the 124 evaluable patients, 32 (25.8%) were classified as PRED_R and 92 as RED_NR by the 3-gene methylation signature. PRED_R did not have a significantly different second-line PFS (HR 0.95, 95%CI 0.57-1.57; P = 0.84) or OS (HR 0.91, 95%CI 0.51-1.60; P = 0.73) when treated in the bevacizumab-containing study arm compared to PRED_NR. In addition, PRED_R did not show a longer PFS when treated with bevacizumab compared to PRED_R treated with chemotherapy alone (HR 0.95, 95%CI 0.59-1.54; P = 0.83). Furthermore, there was no difference in third-line PFS and the combination of second- and third-line PFS between PRED_R and PRED-NR in the bevacizumab arm. In the control arm, PRED_NR showed a statistically significant shorter PFS compared to PRED_R (HR 0.50, 95%CI 0.22-0.77; P = 0.006), but not OS (HR 0.95, 95%CI 0.51-1.77; P = 0.86).

Conclusion: Our 3-gene methylation signature was not confirmed as predictive biomarker for bevacizumab efficacy in metastatic breast cancer.

(This research project was partially supported by ROCHE Austria GmbH)

Citation Format: Gampenrieder SP, Angela R, Rinnerthaler G, Hackl H, Steiner M, Pulverer W, Weinhaeusel A, Klinglmayr E, Karl T, Ilic S, Hufnagl C, Hauser-Kronberger C, Egle A, Greil R. A 3-gene DNA methylation signature fails to predict response to bevacizumab in metastatic breast cancer patients treated within the TANIA phase III trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-10-07.

DNA Methylation Signatures Predicting Bevacizumab Efficacy in Metastatic Breast Cancer

Background: Biomarkers predicting response to bevacizumab in breast cancer are still missing. Since epigenetic modifications can contribute to an aberrant regulation of angiogenesis and treatment resistance, we investigated the influence of DNA methylation patterns on bevacizumab efficacy. Methods: Genome-wide methylation profiling using the Illumina Infinium HumanMethylation450 BeadChip was performed in archival FFPE specimens of 36 patients with HER2-negative metastatic breast cancer treated with chemotherapy in combination with bevacizumab as first-line therapy (learning set). Based on objective response and progression-free survival (PFS) and considering ER expression, patients were divided in responders (R) and non-responders (NR). Significantly differentially methylated gene loci (CpGs) with a strong change in methylation levels (Δβ>0.15 or Δβ<-0.15) between R and NR were identified and further investigated in 80 bevacizumab-treated breast cancer patients (optimization set) and in 15 patients treated with chemotherapy alone (control set) using targeted deep amplicon bisulfite sequencing. Methylated gene loci were considered predictive if there was a significant association with outcome (PFS) in the optimization set but not in the control set using Spearman rank correlation, Cox regression, and logrank test. Results: Differentially methylated loci in 48 genes were identified, allowing a good separation between R and NR (odds ratio (OR) 101, p<0.0001). Methylation of at least one cytosine in 26 gene-regions was significantly associated with progression-free survival (PFS) in the optimization set, but not in the control set. Using information from the optimization set, the panel was reduced to a 9-gene signature, which could divide patients from the learning set into 2 clusters, thereby predicting response with an OR of 40 (p<0.001) and an AUC of 0.91 (LOOCV). A further restricted 3-gene methylation model showed a significant association of predicted responders with longer PFS in the learning and optimization set even in multivariate analysis with an excellent and good separation of R and NR with AUC=0.94 and AUC=0.86, respectively. Conclusion: Both a 9-gene and 3-gene methylation signature can discriminate between R and NR to a bevacizumab-based therapy in MBC and could help identify patients deriving greater benefit from bevacizumab.

Sidedness and TP53 mutations impact OS in anti-EGFR but not anti-VEGF treated mCRC - an analysis of the KRAS registry of the AGMT (Arbeitsgemeinschaft Medikamentöse Tumortherapie)

Background

In metastatic colorectal cancer (mCRC), the localization of the primary tumour has been shown to be of prognostic as well as predictive relevance.

Methods

With the aim to investigate clinical and molecular disease characteristics with respect to sidedness in a real-world cohort, we analyzed 161 mCRC patients included in the KRAS Registry of the Arbeitsgemeinschaft Medikamentöse Tumortherapie (AGMT) between January 2006 and October 2013.

Results

Right-sided mCRC displayed a worse median overall survival (OS) in comparison to left-sided disease (18.1 months [95%-CI: 14.3–40.7] versus 32.3 months [95%-CI: 25.5–38.6]; HR: 1.63 [95%-CI: 1.13–2.84]; p = 0.013). The choice of the biological agent in front-line therapy had a statistically significant impact on median OS in patients with right-sided tumours (anti-epidermal growth factor receptor (EGFR): 10.6 months [95%-CI: 5.2-NA]; anti-vascular endothelial growth factor (VEGF): 26.2 months [95%-CI: 17.9-NA]; HR: 2.69 [95%-CI: 1.30–12.28]; p = 0.015) but not in patients with left-sided tumours (anti-EGFR: 37.0 months [95%-CI: 20.2–56.6]; anti-VEGF: 32.3 months [95%-CI: 23.6–41.1]; HR: 0.97 [95%-CI: 0.56–1.66]; p = 0.905). When evaluating molecular characteristics of tumour samples, we found a clinically meaningful trend towards an inferior OS in TP53 mutant mCRC treated with anti-EGFR based therapy compared to anti-VEGF based therapy (17.1 months [95%-CI: 8.7-NA] versus 38.3 months [95%-CI: 23.6–48.0], HR = 1.95 [95%-CI: 0.95–5.88]; p = 0.066), which was not significantly dependent on sidedness. This was not the case in patients with TP53 wild-type tumours. Therefore we evaluated the combined impact of sidedness and TP53 mutation status in the anti-EGFR treated cohort and patients with left-sided/TP53 wild-type mCRC showed the longest median OS (38.9 months) of all groups (right-sided/TP53 mutant: 12.1 months; right-sided/TP53 wild-type: 8.9 months; left-sided/TP53 mutant: 18.4 months; p = 0.020).

Conclusions

TP53 mutation and right-sidedness are associated with shorter OS in patients treated with anti-EGFR based therapy but not with anti-VEGF based therapy. The confirmation of the predictive value of TP53 mutation status in a larger cohort is warranted.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3955-4) contains supplementary material, which is available to authorized users.

Abstract P6-07-10: DNA methylation signature predicting bevacizumab efficacy in metastatic breast cancer

Background: Biomarkers predicting response to bevacizumab containing therapy in breast cancer are still missing. Since epigenetic modifications can contribute to an aberrant regulation of angiogenesis and to treatment resistance, we investigated the influence of DNA methylation on bevacizumab efficacy.

Patients and methods: A genome-wide methylation profiling using the Illumina Infinium HumanMethylation450 BeadChip was performed in archival FFPE specimen of 36 patients with HER2-negative metastatic breast cancer treated with chemotherapy in combination with bevacizumab as first-line therapy (learning set). Based on objective response and progression-free survival (PFS) and considering ER expression, patients were divided in responders (R) and non-responders (NR). Differentially methylated gene loci (methylation variable position = MVP) and differentially methylated regions (DMR) between R and NR were identified. Only significant sites with a strong change in methylation levels (Δβ&gt;0.15 or Δβ&lt;-0.15), an area under the curve of at least 0.85 by logistic regression analysis, and/or sites in proximity to genes functionally involved in angiogenesis and carcinogenesis were selected and further validated. Validation was performed in 81 bevacizumab treated breast cancer patients (validation set) and in 15 patients treated with chemotherapy only (control set) using targeted bisulfite sequencing. Methylated gene loci were considered predictive if there was a significant association with outcome (PFS) in the validation set but not in the control set using Spearman rank correlation, Cox regression, and logrank test.

Results: In the learning set 435 MVPs (p&lt;0.001) and 144 DMRs (adjusted combined p&lt;0.0001 with at least 3 significant MVPs p&lt;0.05 in the same region) showed significantly different methylation between R and NR. In R 152 sites were hypermethylated with a median change of methylation (Δβ) of 0.13; 283 sites were hypomethylated with a median Δβ of -0.09. A methylation signature of 48 genes was specified allowing a good separation between responders and non-responders (odds ratio=101, p&lt;0.0001; data presented at the 38th SABCS 2015, P3-07-43). At least one methylated cytosine in close proximity to 24 of these genes showed a significant association with PFS in the validation set but was not (or in the other direction) in the control set. Based on these data the methylation signature predicting long lasting response to bevacizumab could be reduced to 24 genes including several genes involved in angiogenesis and carcinogenesis, respectively (FLT1 also known as VEGFR-1, MLH1, GNAS, APC, DKK3, WNT2B and COL4A1).

Conclusion: A 24-gene methylation signature can reproducible discriminate between responders and non-responders to a bevacizumab-based therapy in breast cancer and could help to identify patients deriving greater benefit from anti-VEGF agents.

Citation Format: Gampenrieder SP, Rinnerthaler G, Pulverer W, Weinhäusel A, Hufnagl C, Hackl H, Hauser-Kronberger C, Mlineritsch B, Greil R. DNA methylation signature predicting bevacizumab efficacy in metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-07-10.

Independent Prognostic Value of Serum Markers in Diffuse Large B-Cell Lymphoma in the Era of the NCCN-IPI

BACKGROUND

Several serum parameters have been evaluated for adding prognostic value to clinical scoring systems in diffuse large B-cell lymphoma (DLBCL), but none of the reports used multivariate testing of more than one parameter at a time. The goal of this study was to validate widely available serum parameters for their independent prognostic impact in the era of the National Comprehensive Cancer Network-International Prognostic Index (NCCN-IPI) score to determine which were the most useful.

PATIENTS AND METHODS

This retrospective bicenter analysis includes 515 unselected patients with DLBCL who were treated with rituximab and anthracycline-based chemoimmunotherapy between 2004 and January 2014.

RESULTS

Anemia, high C-reactive protein, and high bilirubin levels had an independent prognostic value for survival in multivariate analyses in addition to the NCCN-IPI, whereas neutrophil-to-lymphocyte ratio, high gamma-glutamyl transferase levels, and platelets-to-lymphocyte ratio did not.

CONCLUSIONS

In our cohort, we describe the most promising markers to improve the NCCN-IPI. Anemia and high C-reactive protein levels retain their power in multivariate testing even in the era of the NCCN-IPI. The negative role of high bilirubin levels may be associated as a marker of liver function. Further studies are warranted to incorporate these markers into prognostic models and define their role opposite novel molecular markers.

Anti-Hu Antibody Associated Paraneoplastic Cerebellar Degeneration in Head and Neck Cancer

Background

Paraneoplastic syndromes are most frequently associated with small cell lung carcinoma, hematologic and gynecologic malignancies while reports in head and neck cancer are rare.

Case presentation

We present the case of a 60-year old female patient who developed paraneoplastic cerebellar degeneration upon locoregional recurrence of a poorly differentiated spindle cell carcinoma of the nasal cavity and paranasal sinus. The neurological symptoms, especially ataxia, stabilized after resection of tumor recurrence and concomitant chemoradiotherapy whereas anti-Hu-antibodies remained positive. Despite the unfavorable prognosis of paraneoplastic neurological disorders associated with onconeural antibodies, the patient achieved long-standing stabilization of neurological symptoms.

Conclusion

We report the first patient with anti-Hu antibodies and paraneoplastic cerebellar degeneration associated with a spindle cell carcinoma of the head and neck. We recommend that evaluation of neurological symptoms in patients with this tumor entity should also include paraneoplastic syndromes as differential diagnoses and suggest early extensive screening for onconeural antibodies.

CYP39A1 polymorphism is associated with toxicity during intensive induction chemotherapy in patients with advanced head and neck cancer

Background

Induction chemotherapy incorporating docetaxel, cisplatin and 5- fluorouracil before radiotherapy may improve the outcome of patients with advanced head and neck cancer. Nevertheless, the addition of docetaxel increases hematological toxicity and infectious complications. Therefore, genetic markers predicting toxicity and efficacy of this treatment regimen may help to identify patients, who would have the most benefit from this intensive treatment.

Methods

A cohort of 78 patients with advanced head and neck cancer treated with induction chemotherapy was assessed for clinical outcome and toxicity during treatment with curative intention. Genetic polymorphisms primary associated with treatment efficacy (ERCC2-rs13181, rs1799793, ERCC1-rs3212986, rs11615, XRCC1-rs25487) or with docetaxel caused toxicity (CYP39A1-rs7761731, SLCO1B3-rs11045585) were evaluated in all patients. The results of these analyses were correlated with the clinical outcome of the patients (loco regional control, progression free survival, overall survival) and treatment related toxicity during induction chemotherapy.

Results

Median progression free survival and overall survival was 20 and 31 months in an intention to treat analysis, respectively. Overall response rate to induction chemotherapy was high with 78.1 % of all patients. None of the polymorphisms tested was associated with the clinical outcome of the patients. Genotype A of the CYP39A1 rs7761731 polymorphism was associated with a higher incidence of leucopenia and infections or death during induction chemotherapy.

Conclusions

Intensive induction chemotherapy results in a high response rate in the majority of patients. None of the polymorphisms tested was associated with the clinical outcome of the patients. The CYP39A1 polymorphism rs7761731 may help to identify patients at high risk for treatment related toxicity.

Lapatinib-plus-pegylated liposomal doxorubicin in advanced HER2-positive breast cancer following trastuzumab: a phase II trial

BACKGROUND

Trastuzumab, one important treatment option for HER2-positive metastatic breast cancer (MBC) is limited by its cardiotoxic potential. Lapatinib and pegylated liposomal doxorubicin (PLD) represent a cardiosparing alternative that can cross the blood brain barrier. This is important, because one third of breast cancer patients develop brain metastases.

PATIENTS AND METHODS

We included 24 patients with HER2-positive MBC progressing under trastuzumab. They received 1,250 mg lapatinib daily until progression plus PLD (40 mg/m(2)) every 4 weeks for maximal 6 cycles. The primary end-point was the overall response rate (ORR). Secondary end-points were progression-free survival (PFS), overall survival (OS), 1-year PFS and 1-year OS rates.

RESULTS

ORR was 54%. Median PFS was 5.8 and median OS 23.3 months. The one-year PFS rate was 27% and 1-year OS rate 76%.

CONCLUSION

Lapatinib-plus-PLD is active and safe in HER2-positive MBC, especially suitable for patients with cardiological risk or brain metastases.

Increased body mass index is associated with improved overall survival in diffuse large B-cell lymphoma

BACKGROUND

Obesity is a well-known risk factor for the development of several types of cancer including lymphomas, but its influence on the course of disease is fairly unknown. Recently, a retrospective cancer registry analysis demonstrated significantly prolonged survival for overweight and obese patients with diffuse large B-cell lymphoma (DLBCL). The study population almost exclusively consisted of male US American patients of lower socioeconomic status and one-fifth of patients received cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP) chemotherapy without rituximab. Therefore, it remains unclear if these results can be extrapolated to the general DLBCL population.

PATIENTS AND METHODS

This retrospective single-center analysis included 183 unselected DLBCL patients who were treated with rituximab and standard-dosed anthracycline-based chemoimmunotherapy as first-line therapy between January 2004 and December 2012. Patients were stratified by body mass index (BMI) into 'low BMI' (<25.0 kg/m(2)) and 'high BMI' (≥25.0 kg/m(2)).

RESULTS

The two groups were well balanced regarding age, performance score, international prognostic index, B-symptoms and extranodal involvement. However, there was a trend for male sex (P = 0.053) and higher-stage disease (P = 0.066) in the high-BMI group. Patients with higher BMI had significantly longer overall survival (OS; hazard ratio [HR] 0.546; P = 0.035) with 80.9% of patients alive at 3 years versus 64.2% in the low-BMI group. BMI was also an independent prognostic factor for OS in multivariate analysis (HR 0.557; P = 0.043).

CONCLUSION

We could show a significant association between overweight/obesity and improved OS in an unselected DLBCL cohort.

A modified Phenol-chloroform extraction method for isolating circulating cell free DNA of tumor patients

Searching for new cancer biomarkers, circulating cell-free DNA (cfDNA) has become an appealing target of interest as an elevated level of cfDNA has been detected in the circulation of cancer patients in comparison with healthy controls. Since cfDNA can be isolated from the circulation and other body fluids of patients without harming their physical condition, cfDNA is becoming a promising candidate as a novel non-invasive biomarker for cancer. The challenge in the diagnostic analysis of cfDNA is its very low presence in human plasma/serum and its partially strong fragmentation. Here we evaluated a modified phenol/chloroform extraction method for the isolation of cfDNA and compared it with published standard methods for cfDNA isolation.

Effect of the AMP-kinase modulators AICAR, metformin and compound C on insulin secretion of INS-1E rat insulinoma cells under standard cell culture conditions

BACKGROUND/AIMS

The function of β-cells is regulated by nutrient uptake and metabolism. The cells' metabolic state can be expressed as concentration ratios of AMP, ADP and ATP. Relative changes in these ratios regulate insulin release. An increase in the intracellular ATP concentration causes closure of K(ATP) channels and cell membrane depolarization, which triggers stimulus-secretion coupling (SSC). In addition to K(ATP) channels, the AMP-dependent protein kinase (AMPK), a major cellular fuel sensor in a variety of cells and tissues, also affects insulin secretion and β-cell survival. In a previous study we found that the widely used AMPK inhibitor compound C retards proliferation and induces apoptosis in the rat β-cell line INS-1E. We therefore tested the effects of AMPK activators (AICAR and metformin), and compound C on AMPK phosphorylation, insulin secretion, K(ATP) channel currents, cell membrane potential, intracellular calcium concentration, apoptosis and cell cycle distribution of INS-1E cells under standard cell culture conditions (11 mM glucose).

METHODS

Western blotting, ELISA, patch-clamp, calcium imaging and flow cytometry.

RESULTS

We found that basal AMPK phosphorylation is enhanced by AICAR (1 mM) and metformin (1 mM) but remained unaffected by compound C (10 μM). Both AICAR and compound C stimulated basal insulin secretion whereas metformin had no effect. Pre-incubation with AICAR (1 mM) caused an inhibition of K(ATP) currents but did not significantly alter the average cell membrane potential (Vm) or the threshold potential of electrical activity. Acute administration of AICAR (300 μM) led to a depolarization of Vm, which was not due to an inhibition of the basal- or glucose-induced chloride conductance, and was not accompanied by elevations of intracellular calcium (Ca(i)). AICAR had no additive blocking effect on K(ATP) currents when applied together with tolbutamide. Compound C applied over 24 hours induced an increase in the percentage of cells positive for caspase activity, whereas AICAR (1 mM) applied for 48 hours was without effect. Medium glucose concentration <3 mM caused cell cycle arrest, caspase activation and an increase of cell granularity.

CONCLUSION

We conclude that under standard cell culture conditions the AMPK modulators AICAR and compound C, but not metformin, stimulate insulin secretion by AMPK-independent mechanisms.

The phytostilbene resveratrol induces apoptosis in INS-1E rat insulinoma cells

We investigated the effect of resveratrol on proliferation and induction of apoptosis of INS-1E rat insulinoma cells by cell counting, crystal violet staining, flow cytometry and immunoblotting. Resveratrol treatment of INS-1E cells at concentrations > or =50 microM resulted in a dose-dependent inhibition of cell proliferation, accumulation of the cells in the S and G0/G1 phase and a significant increase of the percentage of apoptotic cells. This was paralleled by an increase of cell granularity, apoptotic volume decrease (AVD), exposure of phosphatidylserine at the outer leaflet of the plasma membrane, an increase of the 7-AAD signal and caspase activation. The AMP-kinase (AMPK) inhibitor compound C (10 microM) significantly inhibited cell proliferation and induced caspase activation within 48 hours but this effect was not modified by resveratrol suggesting that AMPK is not a major target involved in mediating the proapoptotic effect of resveratrol in INS-1E cells. Immunoblotting revealed a significant inhibition of Akt (PKB) phosphorylation by 100 muM resveratrol within 1 hour. Addition of insulin (10 microM) to the culture medium strongly enhanced basal Akt phosphorylation. This enhancement was significantly attenuated by 50 and 100 microM resveratrol. We conclude that the antiproliferative/proapoptotic effect of resveratrol on INS-1E cells is due to negative interference with Akt signaling and most likely disruption of auto/paracrine insulin signaling.

[Comparison of central corneal thickness in patients participating in a glaucoma screening programme and those who were examined in the glaucoma unit]

BACKGROUND

The aim of this study was to compare central corneal thickness (CCT) and intraocular pressure in patients participating in a glaucoma screening programme and patients who were examined in the glaucoma unit.

MATERIALS AND METHODS

406 patients of a glaucoma screening programme (Salzburg-Moorfields collaborative glaucoma study) were included in this study. In addition a group of 406 patients who were admitted to the glaucoma clinic for a detailed glaucoma examination was included (outpatient clinic group). In all participants central corneal thickness (CCT) was measured and possible relations of CCT within the study groups were statistically analysed.

RESULTS

In the population screening group the mean central corneal thickness in normal subjects was 536+/-4.3 microm, in patients with ocular hypertension (OHT) 552+/-5.7 microm, patients suffering from a normal tension glaucoma (NTG) showed a mean CCT of 534+/-14.2 microm and those with primary open angle glaucoma (POAG) had a value of 521+/-17.9 microm. In the 'outpatient clinic group' the OHT subgroup had a mean CCT of 553+/-6.8 microm, the NTG subgroup of 529+/-26.5 microm and the one with POAG had a mean of 527+/-19.8 microm. In addition, CCT was measured in all glaucoma patients whose "partner" eye was healthy (544+/-5 microm) and included in this study as part of the normal subgroup. In both groups (screening group and outpatient group), CCT was significantly higher in OHT patients than in normals. In contrast, no statistically significant difference between normals and NTG or POAG patients was detected. Intraocular pressure was significantly lower in the screening groups than in the other ones.

CONCLUSIONS

Our data confirm the previously published results concerning OHT and healthy subjects. In this study no significant difference between NTG or POAG subjects and normal eyes was detected. The lower IOP in the screening population can be explained by the fact that patients contacting the screening program are self selected whereas patients of the glaucoma unit are admitted by practising ophthalmologists and are, therefore, rather advanced cases or carrying special risk factors.

Effect of folate supplementation on N-terminal pro-brain natriuretic peptide

BACKGROUND

Increased plasma homocysteine (HCY) has been suggested as a novel risk factor for chronic heart failure (CHF). This study investigated the effect of a HCY lowering therapy by folic acid (FA) supplementation on N-terminal pro-brain natriuretic peptide (NT-proBNP) in healthy subjects.

METHODS

We treated 61 healthy individuals (median age [25th-75th percentile]: 57 [53-69] years with placebo, 0.4, 1.0 or 5.0 mg FA daily for 2 months. Fasting blood samples were taken after 0, 4 and 8 weeks. Serum HCY, folate, vitamin B12 and NT-proBNP were studied.

RESULTS

Baseline HCY, folate and NT-proBNP levels were 13.6 (10.0-16.4) micromol/L, 5.0 (3.8-6.4) microg/L and 40.4 (21.8-67.3) ng/L, respectively. Serum folate increased during supplementation (4 weeks of placebo, 0.4, 1.0, 5.0 mg of FA: -9%, +131%, +150%, +314%; 8 weeks: -72%, +152%, +185%, +62%) and HCY decreased (4 weeks: +2%, -12%, -20%, -15%; 8 weeks: -2%, -9%, -17%, -15%) in the treatment groups. NT-proBNP did not change within groups. Pooling FA treated subjects, individuals with a baseline NT-proBNP above the median of 40 ng/L exhibited a 20% decrease of NT-proBNP (significant on a 10% level) while HCY decreased by 15%.

CONCLUSION

FA supplementation with doses between 0.4 and 5 mg does not affect NT-proBNP in healthy subjects with an NT-proBNP concentration <40 ng/L, but possibly lowers NT-proBNP in individuals with NT-proBNP levels >40 ng/L.

Folate supplementation does not affect biochemical markers of bone turnover

BACKGROUND

Recently, increased plasma homocysteine (HCY) has been suggested as a novel independent risk factor for osteoporotic fractures. This study aimed to analyze the effect of a HCY lowering therapy by folic acid (FA) supplementation on biochemical bone markers in healthy subjects.

MATERIAL AND METHODS

We treated 61 healthy individuals (mean age: 58+/-8 years) with placebo, 0.4, 1 or 5 mg FA daily for 2 months. Fasting blood samples were taken after 0, 4 and 8 weeks. Serum HCY, folate, vitamin B12, osteocalcin (OC), procollagen type I N-terminal propeptide (PINP) and C-terminal telopeptides of human collagen type I (CTX) were studied.

RESULTS

Overall baseline HCY and folate levels were 13.4 +/- 3.6 micromol/L and 5.7 +/- 3.0 microg/L, respectively. Participants exhibited normal baseline OC, PINP and CTX levels. Serum folate increased during supplementation (4 weeks of placebo, 0.4, 1 and 5 mg of FA: -7, +160, +162 and +436 %; 8 weeks: -6, +305, +340 and +216 %) and HCY decreased (4 weeks of placebo, 0.4, 1 and 5 mg of FA: +2, -14, -21 and -17 %; 8 weeks: +2, -8, -20 and -17 %) in the treatment groups, but not in the placebo group. OC (placebo: 22.8 vs. 23.0 vs. 23.6; 0.4 mg FA: 21.6 vs. 22.1 vs. 24.1; 1 mg FA: 23.7 vs. 22.6 vs. 23.4; 5 mg FA: 24.1 vs. 20.5 vs. 20.9 microg/L), PINP (placebo: 43.5 vs. 51.3 vs. 46.5; 0.4 mg FA: 34.0 vs. 34.1 vs. 39.5; 1 mg FA: 43.6 vs. 39.7 vs. 43.2; 5 mg FA: 41.1 vs. 38.7 vs. 37.4 microg/L) and CTX (placebo: 258 vs. 360 vs. 321; 0.4 mg FA: 229 vs. 290 vs. 315; 1 mg FA: 319 vs. 325 vs. 301; 5 mg FA: 293 vs. 321 vs. 304 ng/L) did not change throughout the study.

CONCLUSION

Short-term FA supplementation does not affect biochemical bone markers in non-osteoporotic subjects with a low folate status.

Fahrgewohnheiten von Patienten mit Glaukom

BACKGROUND

Central visual field defects due to glaucoma are common, increasing with old age. Impaired visual processing, for instance caused by glaucoma, may play a role in the aetiology of car accidents involving older drivers which can result in personal injury. Mandatory eye exams with assessment of the visual field in elderly people holding a driving licence will become more and more important, especially in a continuously ageing and increasingly mobile population.

MATERIALS AND METHODS

In this prospective study, 80 patients with overt glaucoma and 52 patients without glaucoma, all holders of a valid driving licence, were enrolled. For each patient, the best corrected visual acuity was recorded and an examination of the central visual field was performed with automatic perimetry. In addition, a detailed questionnaire about the current driving habits of the patient was requested.

RESULTS

In summary, 29 patients (36 %; 95 % CI: 26 - 48 %) of 80 glaucoma patients were driving a motor vehicle with binocular congruent scotomata within the central 30 degrees visual field, which is not sufficient to meet current legal requirements in Austria. In addition, 3 out of 29 impaired patients had a visual acuity that was below the mandatory legal requirements. A total of 39 patients (49 %; 95 % CI: 37 - 60 %) of the glaucoma patients fulfilled legal requirements. Examination of these patients showed only monocular or binocular central visual field defects that were not congruent. However, 12 (15 %; 95 % CI: 8 - 25 %) patients were holders of a valid driving licence, but had stopped driving some time ago. Based on the prevalence of glaucoma and the number of driving licence holders, the projected number of actively driving glaucoma patients who do not meet the legal requirements regarding the visual field is probably around 15,400 (7,400 - 29,500) in Austria and around 163,500 (79,000 - 313,500) in Germany.

CONCLUSIONS

Time limits for the validity of the driving licence within the European Community have been set. In addition, the legal requirements for driving a motor vehicle should also be clearly defined, especially the requirements regarding the visual field and the acceptable dimensions of central scotomata. In addition, a mandatory eye exam for older drivers to be performed by ophthalmologists should be considered in order to detect persons posing a safety risk in traffic.