Hypoxia Scores Research Articles

Vascular responses to radiotherapy and androgen-deprivation therapy in experimental prostate cancer

BackgroundRadiotherapy (RT) and androgen-deprivation therapy (ADT) are standard treatments for advanced prostate cancer (PC). Tumor vascularization is recognized as an important physiological feature likely to impact on both RT and ADT response, and this study therefore aimed to characterize the vascular responses to RT and ADT in experimental PC.MethodsUsing mice implanted with CWR22 PC xenografts, vascular responses to RT and ADT by castration were visualized in vivo by DCE MRI, before contrast-enhancement curves were analyzed both semi-quantitatively and by pharmacokinetic modeling. Extracted image parameters were correlated to the results from ex vivo quantitative fluorescent immunohistochemical analysis (qIHC) of tumor vascularization (9 F1), perfusion (Hoechst 33342), and hypoxia (pimonidazole), performed on tissue sections made from tumors excised directly after DCE MRI.ResultsCompared to untreated (Ctrl) tumors, an improved and highly functional vascularization was detected in androgen-deprived (AD) tumors, reflected by increases in DCE MRI parameters and by increased number of vessels (VN), vessel density ( VD), and vessel area fraction ( VF) from qIHC. Although total hypoxic fractions ( HF) did not change, estimated acute hypoxia scores ( AHS) – the proportion of hypoxia staining within 50 μm from perfusion staining – were increased in AD tumors compared to in Ctrl tumors. Five to six months after ADT renewed castration-resistant (CR) tumor growth appeared with an even further enhanced tumor vascularization. Compared to the large vascular changes induced by ADT, RT induced minor vascular changes. Correlating DCE MRI and qIHC parameters unveiled the semi-quantitative parameters area under curve ( AUC) from initial time-points to strongly correlate with VD and VF, whereas estimation of vessel size ( VS) by DCE MRI required pharmacokinetic modeling. HF was not correlated to any DCE MRI parameter, however, AHS may be estimated after pharmacokinetic modeling. Interestingly, such modeling also detected tumor necrosis very strongly.ConclusionsDCE MRI reliably allows non-invasive assessment of tumors’ vascular function. The findings of increased tumor vascularization after ADT encourage further studies into whether these changes are beneficial for combined RT, or if treatment with anti-angiogenic therapy may be a strategy to improve the therapeutic efficacy of ADT in advanced PC.

Abstract LB-440: Low density array profiling of head and neck squamous cell carcinoma utilizing a 25-gene signature can reliably identify hypoxic tumors

Abstract Purpose: Administering hypoxia modifying therapy to patients with head and neck squamous cell carcinoma (HNSCC) improves outcomes in those with identified hypoxic tumors. As no method for measuring tumor hypoxia has demonstrated clinical utility, this study aimed to validate use of a gene expression signature with a TaqMan Low Density Array (TLDA) platform. Experimental design: Tumor samples (n=201) from 80 HNSCC patients were collected prospectively from two centers. Fifty-three patients received pimonidazole prior to surgery. Hypoxia scores (TLDA HS) were obtained by quantitative real-time PCR (qPCR) using a 25-gene signature and customized TLDA cards. Assay performance was assessed as coefficient of variation (CoV). Relationships with outcome were determined by log-rank analysis. Results: The assay was sensitive with linear reaction efficiencies across a 4log10 range of inputted cDNA (0.001-10 ng/µl). Intra- (CoV=0.5%) and inter- (CoV=0.1%) assay reproducibility were excellent. Intra-tumor heterogeneity was lower for TLDA HS (23.2%) than for pimonidazole (67.2%) or single gene measurements of CA9 (62.2%), VEGFA (45.0%) or HIG2 (39.4%). TLDA HS in HNSCC cell lines increased with decreasing pO2 and was reduced but not completely abrogated in HIF1A silenced cells. TLDA HS correlated with Affymetrix U133 Plus 2.0 microarray HS (p<0.01) and pimonidazole scores (p=0.021). High TLDA HS was associated with worse overall (p=0.037) and recurrence free (p=0.036) survival. Conclusions: Gene expression measurements of hypoxia using a 25-gene signature and TLDA cards are sensitive, reproducible and associated with lower intra-tumor heterogeneity than assaying individual genes or pimonidazole binding. The approach is suitable for application in clinical trials. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-440. doi:1538-7445.AM2012-LB-440

Cerebral cortical thickness and a history of obstetric complications in schizophrenia

IntroductionMagnetic resonance imaging (MRI) studies have demonstrated that patients with schizophrenia have thinner brain cortices compared with healthy control subjects. Neurodevelopment is vulnerable to obstetric complications (OCs) such as hypoxia and birth trauma, factors that are also related to increased risk of developing schizophrenia. With the hypothesis that OCs might explain the thinner cortices found in schizophrenia, we studied patients with schizophrenia and healthy controls subjects for association between number and severity of OCs and variation in cortical thickness. MethodsMRI scans of 54 adults with schizophrenia or schizoaffective disorder and 54 healthy controls were acquired at Karolinska Institutet, Stockholm, Sweden. Measures of brain cortical thickness were obtained using automated computer processing (FreeSurfer). OCs were assessed from obstetric records and scored blindly according to the McNeil–Sjöström scale. At numerous cortical locations, putative effects of OCs on cortical thickness variation were tested for each trimester, for labour, for composite OC scores, severe OC scores, and hypoxia scores among patients and controls separately. ResultsNumber and severity of OCs varied among both patient and control subjects but were not associated with cortical thickness in either of the groups. Patients demonstrated thinner brain cortices but there were no significant differences in number and severity of OC scores across groups. ConclusionIn the present study, number and severity of obstetric complications were not associated with brain cortical thickness, in patients with schizophrenia or in healthy control subjects. The thinner brain cortices found in patients with schizophrenia were not explained by a history of OCs.

Influence of Nebulized Unfractionated Heparin and N-Acetylcysteine in Acute Lung Injury After Smoke Inhalation Injury

To determine whether the combination of aerosolized unfractionated heparin and N-acetylcystine reduces 28-days mortality and lung injury scores (LISs) in adult patients with smoke inhalation injury requiring mechanical ventilation. The study was a single-center retrospective study with historical control. The authors included 30 mechanically ventilated adult subjects who were admitted within 48 hours of their bronchoscopy confirmed smoke inhalation injury over a 5-year period. The experimental group was treated with nebulized heparin sulfate, N-acetylcystine, and albuterol sulfate. Controls received ventilation support and albuterol sulfate. The authors calculated acute physiology and chronic health evaluation (APACHE)-III scores on admission in addition to daily LIS for 7 days. The experimental group was divided into five APACHE-III subgroups and matched with inhalation lung injury patients in the historical control group. There was no significant difference in initial APACHE-III scores or LISs between groups (alpha = 0.05) upon entry to the study. The experimental group showed significant improvement in LISs, respiratory resistance and compliance measurements, and hypoxia scores as compared with controls throughout the duration of the study. There was a statistically significant survival benefit in the experimental group that was most pronounced in patients with APACHE-III scores >35. Survival for the control vs experimental group was 0.5714 +/- 0.1497 vs 0.9375 +/- 0.0605, respectively, (risk ratio -0.0055; 95% confidence interval -0.0314-0.0204; hazard ratio 1.003; number needed to treat 2.7). The use of aerosolized unfractionated heparin and N-acetylcystine attenuates lung injury and the progression of acute respiratory distress syndrome in ventilated adult patients with acute lung injury following smoke inhalation.

An immunohistochemical assessment of hypoxia in prostate carcinoma using pimonidazole: Implications for radioresistance

To investigate the presence of hypoxia in human prostate carcinoma by using pimonidazole immunohistochemical labeling in radical prostatectomy specimens. Forty-three patients (median age, 69 years; range, 49-83 years) with localized prostate adenocarcinoma received 0.5 gm/m2 i.v. pimonidazole 16-24 h before radical prostatectomy. Hypoxia was detected with a monoclonal antibody directed against pimonidazole and scored in formalin-fixed, paraffin-embedded sections. Median and maximal vessel counts were measured with CD34. Thirty-seven patients completed the study. Pimonidazole binding was present in prostate carcinomas in 34 of 37 patients (92%) and in benign prostatic hyperplasia in 35 of 37 patients (95%). A positive correlation of 3+ pimonidazole binding with Gleason score was demonstrated (Spearman's rank, p = 0.044). Vascularity scores did not correlate with hypoxic status or clinical prognostic parameters. Prostate carcinoma and benign prostatic hyperplasia have significant areas of hypoxia; greater hypoxia scores are seen with more aggressive prostate cancer. It is postulated that a hypoxic microenvironment within the prostate might be responsible for the promotion of secondary genetic alterations and angiogenic stimulation, leading to malignant progression, a more aggressive cell phenotype, and greater radioresistance. Modification of radiation regimens to specifically target hypoxia might improve local tumor control.