| 1. |
- Davies, G., et al.
(author)
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Genetic contributions to variation in general cognitive function : a meta-analysis of genome-wide association studies in the CHARGE consortium (N=53 949)
- 2015
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In: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 20:2, s. 183-192
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Journal article (peer-reviewed)abstract
- General cognitive function is substantially heritable across the human life course from adolescence to old age. We investigated the genetic contribution to variation in this important, health-and well-being-related trait in middle-aged and older adults. We conducted a meta-analysis of genome-wide association studies of 31 cohorts (N = 53 949) in which the participants had undertaken multiple, diverse cognitive tests. A general cognitive function phenotype was tested for, and created in each cohort by principal component analysis. We report 13 genome-wide significant single-nucleotide polymorphism (SNP) associations in three genomic regions, 6q16.1, 14q12 and 19q13.32 (best SNP and closest gene, respectively: rs10457441, P = 3.93 x 10(-9), MIR2113; rs17522122, P = 2.55 x 10(-8), AKAP6; rs10119, P = 5.67 x 10(-9), APOE/TOMM40). We report one gene-based significant association with the HMGN1 gene located on chromosome 21 (P = 1x10(-6)). These genes have previously been associated with neuropsychiatric phenotypes. Meta-analysis results are consistent with a polygenic model of inheritance. To estimate SNP-based heritability, the genome-wide complex trait analysis procedure was applied to two large cohorts, the Atherosclerosis Risk in Communities Study (N = 6617) and the Health and Retirement Study (N = 5976). The proportion of phenotypic variation accounted for by all genotyped common SNPs was 29% (s.e. = 5%) and 28% (s.e. = 7%), respectively. Using polygenic prediction analysis, similar to 1.2% of the variance in general cognitive function was predicted in the Generation Scotland cohort (N = 5487; P = 1.5 x 10(-17)). In hypothesis-driven tests, there was significant association between general cognitive function and four genes previously associated with Alzheimer's disease: TOMM40, APOE, ABCG1 and MEF2C.
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| 2. |
- Postmus, I., et al.
(author)
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Meta-analysis of genome-wide association studies of HDL cholesterol response to statins
- 2016
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In: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 53:12, s. 835-45
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Journal article (peer-reviewed)abstract
- Background In addition to lowering low density lipoprotein cholesterol (LDL-C), statin therapy also raises high density lipoprotein cholesterol (HDL-C) levels. Interindividual variation in HDL-C response to statins may be partially explained by genetic variation. Methods and results We performed a meta-analysis of genome-wide association studies (GWAS) to identify variants with an effect on statin-induced high density lipoprotein cholesterol (HDL-C) changes. The 123 most promising signals with p<1x10(-4) from the 16 769 statin-treated participants in the first analysis stage were followed up in an independent group of 10 951 statin-treated individuals, providing a total sample size of 27 720 individuals. The only associations of genome-wide significance (p<5x10(-8)) were between minor alleles at the CETP locus and greater HDL-C response to statin treatment. Conclusions Based on results from this study that included a relatively large sample size, we suggest that CETP may be the only detectable locus with common genetic variants that influence HDL-C response to statins substantially in individuals of European descent. Although CETP is known to be associated with HDL-C, we provide evidence that this pharmacogenetic effect is independent of its association with baseline HDL-C levels.
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| 3. |
- Postmus, Iris, et al.
(author)
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Pharmacogenetic meta-analysis of genome-wide association studies of LDL cholesterol response to statins.
- 2014
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In: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5
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Journal article (peer-reviewed)abstract
- Statins effectively lower LDL cholesterol levels in large studies and the observed interindividual response variability may be partially explained by genetic variation. Here we perform a pharmacogenetic meta-analysis of genome-wide association studies (GWAS) in studies addressing the LDL cholesterol response to statins, including up to 18,596 statin-treated subjects. We validate the most promising signals in a further 22,318 statin recipients and identify two loci, SORT1/CELSR2/PSRC1 and SLCO1B1, not previously identified in GWAS. Moreover, we confirm the previously described associations with APOE and LPA. Our findings advance the understanding of the pharmacogenetic architecture of statin response.
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| 4. |
- Van Eunen, K., et al.
(author)
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Measuring enzyme activities under standardized in-vivo like conditions for systems biology
- 2010
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In: FEBS Journal. - : Wiley. - 1742-4658 .- 1742-464X. ; 277:3, s. 749-760
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Journal article (peer-reviewed)abstract
- Realistic quantitative models require data from many laboratories. Therefore, standardization of experimental systems and assay conditions is crucial. Moreover, standards should be representative of the in vivo conditions. However, most often, enzyme-kinetic parameters are measured under assay conditions that yield the maximum activity of each enzyme. In practice, this means that the kinetic parameters of different enzymes are measured in different buffers, at different pH values, with different ionic strengths, etc. In a joint effort of the Dutch Vertical Genomics Consortium, the European Yeast Systems Biology Network and the Standards for Reporting Enzymology Data Commission, we have developed a single assay medium for determining enzyme-kinetic parameters in yeast. The medium is as close as possible to the in vivo situation for the yeast Saccharomyces cerevisiae, and at the same time is experimentally feasible. The in vivo conditions were estimated for S. cerevisiae strain CEN. PK113-7D grown in aerobic glucose-limited chemostat cultures at an extracellular pH of 5.0 and a specific growth rate of 0.1 h(-1). The cytosolic pH and concentrations of calcium, sodium, potassium, phosphorus, sulfur and magnesium were determined. On the basis of these data and literature data, we propose a defined in vivo-like medium containing 300 mm potassium, 50 mm phosphate, 245 mm glutamate, 20 mm sodium, 2 mm free magnesium and 0.5 mm calcium, at a pH of 6.8. The V(max) values of the glycolytic and fermentative enzymes of S. cerevisiae were measured in the new medium. For some enzymes, the results deviated conspicuously from those of assays done under enzyme-specific, optimal conditions
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| 5. |
- Kato, Norihiro, et al.
(author)
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Trans-ancestry genome-wide association study identifies 12 genetic loci influencing blood pressure and implicates a role for DNA methylation
- 2015
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In: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 47:11, s. 1282-1293
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Journal article (peer-reviewed)abstract
- We carried out a trans-ancestry genome-wide association and replication study of blood pressure phenotypes among up to 320,251 individuals of East Asian, European and South Asian ancestry. We find genetic variants at 12 new loci to be associated with blood pressure (P = 3.9 × 10−11 to 5.0 × 10−21). The sentinel blood pressure SNPs are enriched for association with DNA methylation at multiple nearby CpG sites, suggesting that, at some of the loci identified, DNA methylation may lie on the regulatory pathway linking sequence variation to blood pressure. The sentinel SNPs at the 12 new loci point to genes involved in vascular smooth muscle (IGFBP3, KCNK3, PDE3A and PRDM6) and renal (ARHGAP24, OSR1, SLC22A7 and TBX2) function. The new and known genetic variants predict increased left ventricular mass, circulating levels of NT-proBNP, and cardiovascular and all-cause mortality (P = 0.04 to 8.6 × 10−6). Our results provide new evidence for the role of DNA methylation in blood pressure regulation.
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| 6. |
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| 7. |
- van der Veldt, Astrid A. M., et al.
(author)
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Toward Prediction of Efficacy of Chemotherapy : A Proof of Concept Study in Lung Cancer Patients Using [11C]docetaxel and Positron Emission Tomography
- 2013
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In: Clinical Cancer Research. - 1078-0432 .- 1557-3265. ; 19:15, s. 4163-4173
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Journal article (peer-reviewed)abstract
- Purpose:Pharmacokinetics of docetaxel can be measured in vivo using positron emission tomography (PET) and a microdose of radiolabeled docetaxel ([11C]docetaxel). The objective of this study was to investigate whether a [11C]docetaxel PET microdosing study could predict tumor uptake of therapeutic doses of docetaxel.Experimental Design:Docetaxel-naïve lung cancer patients underwent 2 [11C]docetaxel PET scans; one after bolus injection of [11C]docetaxel and another during combined infusion of [11C]docetaxel and a therapeutic dose of docetaxel (75 mg·m−2). Compartmental and spectral analyses were used to quantify [11C]docetaxel tumor kinetics. [11C]docetaxel PET measurements were used to estimate the area under the curve (AUC) of docetaxel in tumors. Tumor response was evaluated using computed tomography scans.Results:Net rates of influx (Ki) of [11C]docetaxel in tumors were comparable during microdosing and therapeutic scans. [11C]docetaxel AUCTumor during the therapeutic scan could be predicted reliably using an impulse response function derived from the microdosing scan together with the plasma curve of [11C]docetaxel during the therapeutic scan. At 90 minutes, the accumulated amount of docetaxel in tumors was less than 1% of the total infused dose of docetaxel. [11C]docetaxel Ki derived from the microdosing scan correlated with AUCTumor of docetaxel (Spearman ρ = 0.715; P = 0.004) during the therapeutic scan and with tumor response to docetaxel therapy (Spearman ρ = −0.800; P = 0.010).Conclusions:Microdosing data of [11C]docetaxel PET can be used to predict tumor uptake of docetaxel during chemotherapy. The present study provides a framework for investigating the PET microdosing concept for radiolabeled anticancer drugs in patients.
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| 8. |
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| 9. |
- Heerspink, Hiddo J L, et al.
(author)
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A pre-specified analysis of the Dapagliflozin and Prevention of Adverse Outcomes in Chronic Kidney Disease (DAPA-CKD) randomized controlled trial on the incidence of abrupt declines in kidney function.
- 2022
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In: Kidney international. - : Elsevier BV. - 1523-1755 .- 0085-2538. ; 101:1, s. 174-184
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Journal article (peer-reviewed)abstract
- This pre-specified analysis of DAPA-CKD assessed the impact of sodium-glucose cotransporter 2 inhibition on abrupt declines in kidney function in high-risk patients based on having chronic kidney disease (CKD) and substantial albuminuria. DAPA-CKD was a randomized, double-blind, placebo-controlled trial that had a median follow-up of 2.4 years. Adults with CKD (urinary albumin-to-creatinine ratio 200-5000 mg/g and estimated glomerular filtration rate 25-75 mL/min/1.73m2) were randomized to dapagliflozin 10 mg/day matched to placebo (2152 individuals each). An abrupt decline in kidney function was defined as a pre-specified endpoint of doubling of serum creatinine between two subsequent study visits. We also assessed a post-hoc analysis of investigator-reported acute kidney injury-related serious adverse events. Doubling of serum creatinine between two subsequent visits (median time-interval 100 days) occurred in 63 (2.9%) and 91 (4.2%) participants in the dapagliflozin and placebo groups, respectively (hazard ratio 0.68 [95% confidence interval 0.49, 0.94]). Accounting for the competing risk of mortality did not alter our findings. There was no heterogeneity in the effect of dapagliflozin on abrupt declines in kidney function based on baseline subgroups. Acute kidney injury-related serious adverse events were not significantly different and occurred in 52 (2.5%) and 69 (3.2%) participants in the dapagliflozin and placebo groups, respectively (0.77 [0.54, 1.10]). Thus, in patients with CKD and substantial albuminuria, dapagliflozin reduced the risk of abrupt declines in kidney function.
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| 10. |
- McMurray, John J. V., et al.
(author)
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Effect of Dapagliflozin on Clinical Outcomes in Patients with Chronic Kidney Disease, With and Without Cardiovascular Disease
- 2021
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In: Circulation. - : Wolters Kluwer. - 0009-7322 .- 1524-4539. ; 143:5, s. 438-448
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Journal article (peer-reviewed)abstract
- Background:Dapagliflozin reduces the risk of end-stage renal disease in patients with chronic kidney disease. We examined the relative risk of cardiovascular and renal events in these patients and the effect of dapagliflozin on either type of event, taking account of history of cardiovascular disease.Methods:In the DAPA-CKD trial (Dapagliflozin and Prevention of Adverse Outcomes in Chronic Kidney Disease), 4304 participants with chronic kidney disease were randomly assigned to dapagliflozin 10 mg once daily or placebo. The primary end point was a composite of sustained decline in estimated glomerular filtration rate ≥50%, end-stage kidney disease, or kidney or cardiovascular death. The secondary end points were a kidney composite outcome (primary end point, minus cardiovascular death), the composite of hospitalization for heart failure or cardiovascular death, and all-cause death. In a prespecified subgroup analysis, we divided patients into primary and secondary prevention subgroups according to history of cardiovascular disease.Results:Secondary prevention patients (n=1610; 37.4%) were older, were more often male, had a higher blood pressure and body mass index, and were more likely to have diabetes. Mean estimated glomerular filtration rate and median urinary albumin-to-creatinine ratio were similar in the primary and secondary prevention groups. The rates of adverse cardiovascular outcomes were higher in the secondary prevention group, but kidney failure occurred at the same rate in the primary and secondary prevention groups. Dapagliflozin reduced the risk of the primary composite outcome to a similar extent in both the primary (hazard ratio, 0.61 [95% CI, 0.48–0.78]) and secondary (0.61 [0.47–0.79]) prevention groups (P-interaction=0.90). This was also true for the composite of heart failure hospitalization or cardiovascular death (0.67 [0.40–1.13] versus 0.70 [0.52–0.94], respectively; P-interaction=0.88), and all-cause mortality (0.63 [0.41–0.98] versus 0.70 [0.51–0.95], respectively; P-interaction=0.71). Rates of adverse events were low overall and did not differ between patients with and without cardiovascular disease.Conclusions:Dapagliflozin reduced the risk of kidney failure, death from cardiovascular causes or hospitalization for heart failure, and prolonged survival in people with chronic kidney disease, with or without type 2 diabetes, independently of the presence of concomitant cardiovascular disease.Registration:URL: https://www.clinicaltrials.gov; Unique identifier: NCT03036150.
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| 11. |
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| 12. |
- de Boer, Rudolf A, et al.
(author)
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The WAP four-disulfide core domain protein HE4 : a novel biomarker for heart failure.
- 2013
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In: JACC. Heart failure. - : Elsevier BV. - 2213-1787 .- 2213-1779. ; 1:2, s. 164-169
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Journal article (peer-reviewed)abstract
- OBJECTIVES: This study investigated clinical determinants and added prognostic value of HE4 as a biomarker not previously described in heart failure (HF).BACKGROUND: Identification of plasma biomarkers that help to risk stratify HF patients may help to improve treatment.METHODS: Plasma HE4 levels were determined in 567 participants of the COACH (Coordinating study evaluating outcomes of Advising and Counseling in Heart failure). Patients had been hospitalized for HF and were followed for 18 months. The primary endpoint of this study was a composite of all-cause mortality and HF hospitalization.RESULTS: HE4 showed a strong correlation with HF severity, according to New York Heart Association functional class and brain natriuretic peptide (BNP) levels (p < 0.001). HE4 also showed a positive correlation with GDF15 (p < 0.001) and, in addition, correlated with kidney function (estimated glomerular filtration rate [eGFR]; p < 0.001). Cox regression analysis revealed that a doubling of HE4 levels was associated with a hazard ratio (HR) of 1.73 (95% confidence interval [CI]: 1.53 to 1.95) for the primary outcome (p < 0.001). After correction for age, gender, BNP, and eGFR, the HR was 1.46 (95% CI: 1.23 to 1.72; p < 0.001), and after additional adjustment for GDF15, the HR lowered to 1.30 (95% CI: 1.07 to 1.59; p = 0.009). The area under the curve in the receiver-operating characteristic curve analysis increased from 0.727 to 0.752 when HE4 was included in the clinical evaluation (p = 0.051). The integrated discrimination improvement and net reclassification index for reclassification showed significant improvements when HE4 was added to the clinical model, and this remained significant after BNP inclusion in the model.CONCLUSIONS: HE4 plasma levels are correlated with markers of HF severity, show prognostic value, and can improve risk assessment in HF.
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| 13. |
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| 14. |
- Mhlekude, Baxolele, et al.
(author)
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Pharmacological inhibition of bromodomain and extra-terminal proteins induces an NRF-2-mediated antiviral state that is subverted by SARS-CoV-2 infection
- 2023
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In: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 19:9
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Journal article (peer-reviewed)abstract
- Inhibitors of bromodomain and extra-terminal proteins (iBETs), including JQ-1, have been suggested as potential prophylactics against SARS-CoV-2 infection. However, molecular mechanisms underlying JQ-1-mediated antiviral activity and its susceptibility to viral subversion remain incompletely understood. Pretreatment of cells with iBETs inhibited infection by SARS-CoV-2 variants and SARS-CoV, but not MERS-CoV. The antiviral activity manifested itself by reduced reporter expression of recombinant viruses, and reduced viral RNA quantities and infectious titers in the culture supernatant. While we confirmed JQ-1-mediated downregulation of expression of angiotensin-converting enzyme 2 (ACE2) and interferon-stimulated genes (ISGs), multi-omics analysis addressing the chromatin accessibility, transcriptome and proteome uncovered induction of an antiviral nuclear factor erythroid 2-related factor 2 (NRF-2)-mediated cytoprotective response as an additional mechanism through which JQ-1 inhibits SARS-CoV-2 replication. Pharmacological inhibition of NRF-2, and knockdown of NRF-2 and its target genes reduced JQ-1-mediated inhibition of SARS-CoV-2 replication. Serial passaging of SARS-CoV-2 in the presence of JQ-1 resulted in predominance of ORF6-deficient variant, which exhibited resistance to JQ-1 and increased sensitivity to exogenously administered type I interferon (IFN-I), suggesting a minimised need for SARS-CoV-2 ORF6-mediated repression of IFN signalling in the presence of JQ-1. Importantly, JQ-1 exhibited a transient antiviral activity when administered prophylactically in human airway bronchial epithelial cells (hBAECs), which was gradually subverted by SARS-CoV-2, and no antiviral activity when administered therapeutically following an established infection. We propose that JQ-1 exerts pleiotropic effects that collectively induce an antiviral state in the host, which is ultimately nullified by SARS-CoV-2 infection, raising questions about the clinical suitability of the iBETs in the context of COVID-19.
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| 15. |
- Nieuwenhuis, Maurice M W, et al.
(author)
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Long-Term Compliance With Nonpharmacologic Treatment of Patients With Heart Failure
- 2012
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In: American Journal of Cardiology. - : Elsevier. - 0002-9149 .- 1879-1913. ; 110:3, s. 392-397
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Journal article (peer-reviewed)abstract
- The aim of this study was to examine long-term compliance with nonpharmacologic treatment of patients with heart failure (HF) and its associated variables. Data from 648 hospitalized patients with HF (mean age 69 +/- 12 years, 38% women, mean left ventricular ejection fraction 33 +/- 14%) were analyzed. Compliance was assessed by means of self-report at baseline and 1, 6, 12, and 18 months after discharge. Patients completed questionnaires on depressive symptoms, HF knowledge, and physical functioning at baseline. Logistic regression analyses were performed to examine independent associations with low long-term compliance. From baseline to 18-month follow-up, long-term compliance with diet and fluid restriction ranged from 77% to 91% and from 72% to 89%, respectively. In contrast, compliance with daily weighing (34% to 85%) and exercise (48% to 64%) was lower. Patients who were in New York Heart Association functional class II were more often noncompliant with fluid restriction (odds ratio [OR] 1.97, 95% confidence interval [CI] 1.25 to 3.08). A lower level of knowledge on HF was independently associated with low compliance with fluid restriction (OR 0.78, 95% CI 0.71 to 0.86) and daily weighing (OR 0.86, 95% CI 0.79 to 0.94). Educational support improved compliance with these recommendations. Female gender (OR 1.91, 95% CI 1.26 to 2.90), left ventricular ejection fraction andgt;= 40% (OR 1.55, 95% CI 1.03 to 2.34), a history of stroke (OR 3.55, 95% CI 1.54 to 8.16), and less physical functioning (OR 0.99, 95% CI 0.98 to 0.99) were associated with low compliance with exercise. In conclusion, long-term compliance with exercise and daily weighing was lower than long-term compliance with advice on diet and fluid restriction. Although knowledge on HF and being offered educational support positively affected compliance with weighing and fluid restriction, these variables were not related to compliance with exercise. Therefore, new approaches to help patients with HF stay physically active are needed. (C) 2012 Elsevier Inc. All rights reserved. (Am J Cardiol 2012;110:392-397)
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| 16. |
- Postmus, Douwe, et al.
(author)
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A trial-based economic evaluation of 2 nurse-led disease management programs in heart failure
- 2011
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In: American Heart Journal. - : Elsevier. - 0002-8703 .- 1097-6744. ; 162:6, s. 1096-1104
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Journal article (peer-reviewed)abstract
- Background Although previously conducted meta-analyses suggest that nurse-led disease management programs in heart failure (HF) can improve patient outcomes, uncertainty regarding the cost-effectiveness of such programs remains. Methods To compare the relative merits of 2 variants of a nurse-led disease management program (basic or intensive support by a nurse specialized in the management of patients with HF) against care as usual (routine follow-up by a cardiologist), a trial-based economic evaluation was conducted alongside the COACH study. Results In terms of costs per life-year, basic support was found to dominate care as usual, whereas the incremental cost-effectiveness ratio between intensive support and basic support was found to be equal to (sic)532,762 per life-year; in terms of costs per quality-adjusted life-year (QALY), basic support was found to dominate both care as usual and intensive support. An assessment of the uncertainty surrounding these findings showed that, at a threshold value of (sic)20,000 per life-year/(sic)20,000 per QALY, basic support was found to have a probability of 69/62% of being optimal against 17/30% and 14/8% for care as usual and intensive support, respectively. The results of our subgroup analysis suggest that a stratified approach based on offering basic support to patients with mild to moderate HF and intensive support to patients with severe HF would be optimal if the willingness-to-pay threshold exceeds (sic)45,345 per life-year/(sic)59,289 per QALY. Conclusions Although the differences in costs and effects among the 3 study groups were not statistically significant, from a decision-making perspective, basic support still had a relatively large probability of generating the highest health outcomes at the lowest costs. Our results also substantiated that a stratified approach based on offering basic support to patients with mild to moderate HF and intensive support to patients with severe HF could further improve health outcomes at slightly higher costs.
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| 17. |
- Postmus, Douwe, et al.
(author)
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The COACH risk engine : a multistate model for predicting survival and hospitalization in patients with heart failure
- 2012
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In: European Journal of Heart Failure. - : Oxford University Press (OUP): Policy B. - 1388-9842 .- 1879-0844. ; 14:2, s. 168-175
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Journal article (peer-reviewed)abstract
- Aims Several models for predicting the prognosis of heart failure (HF) patients have been developed, but all of them focus on a single outcome variable, such as all-cause mortality. The purpose of this study was to develop a multistate model for simultaneously predicting survival and HF-related hospitalization in patients discharged alive from hospital after recovery from acute HF. less thanbrgreater than less thanbrgreater thanMethods and results The model was derived in the COACH (Coordinating Study Evaluating Outcomes of Advising and Counseling in Heart Failure) cohort, a multicentre, randomized controlled trial in which 1023 patients were enrolled after hospitalization because of HF. External validation was attained with the FINN-AKVA (Finish Acute Heart Failure Study) cohort, a prospective, multicentre study with 620 patients hospitalized due to acute HF. The observed vs. predicted 18-month survival was 72.1% vs. 72.3% in the derivation cohort and 71.4% vs. 71.2% in the validation cohort. The corresponding values of the c statistic were 0.733 [95% confidence interval (CI) 0.705-0.761] and 0.702 (95% CI 0.663-0.744), respectively. The models accuracy in predicting HF hospitalization was excellent, with predicted values that closely resembled the values observed in the derivation cohort. less thanbrgreater than less thanbrgreater thanConclusion The COACH risk engine accurately predicted survival and various measures of recurrent hospitalization in (acute) HF patients. It may therefore become a valuable tool in improving and personalizing patient care and optimizing the use of scarce healthcare resources.
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| 18. |
- van der Veldt, Astrid A M, et al.
(author)
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Quantitative Parametric Perfusion Images Using 15O-Labeled Water and a Clinical PET/CT Scanner : test-retest variability in lung cancer
- 2010
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In: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 51:11, s. 1684-1690
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Journal article (peer-reviewed)abstract
- Quantification of tumor perfusion using radioactive water (H215O) and PET is a promising method for monitoring treatment with antiangiogenic agents. However, use of dynamic H215O scans together with a fully 3-dimensional clinical PET/CT scanner needs to be validated. The purpose of the present study was to assess validity and reproducibility of dynamic H215O PET/CT scans for measuring tumor perfusion and validate the quantitative accuracy of parametric perfusion images.Methods:Eleven patients with non–small cell lung cancer were included in this study. Patients underwent 2 dynamic H215O (370 MBq) PET scans on the same day. During the first scan, arterial blood was withdrawn continuously. Input functions were derived from blood sampler data and the ascending aorta as seen in the images themselves (image-derived input function [IDIF]). Parametric perfusion images were computed using a basis function implementation of the standard single-tissue-compartment model. Volumes of interest (VOIs) were delineated on low-dose CT (LD-CT) and parametric perfusion images.Results:VOIs could be accurately delineated on both LD-CT and parametric perfusion images. These parametric perfusion images had excellent image quality and quantitative accuracy when compared with perfusion values determined by nonlinear regression. Good correlation between perfusion values derived from the blood sampler input function and IDIF was found (Pearson correlation coefficient, r = 0.964; P < 0.001). Test–retest variability of tumor perfusion was 16% and 20% when delineated on LD-CT and parametric perfusion images, respectively.Conclusion:The use of ascending aorta IDIFs is an accurate alternative to arterial blood sampling for quantification of tumor perfusion. Image quality obtained with a clinical PET/CT scanner enables generation of accurate parametric perfusion images. VOIs delineated on LD-CT have the highest reproducibility, and changes of more than 16% in tumor perfusion are likely to represent treatment effects.
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| 19. |
- van der Veldt, Astrid A. M., et al.
(author)
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Rapid Decrease in Delivery of Chemotherapy to Tumors after Anti-VEGF Therapy : Implications for Scheduling of Anti-Angiogenic Drugs
- 2012
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In: Cancer Cell. - : Elsevier BV. - 1535-6108 .- 1878-3686. ; 21:1, s. 82-91
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Journal article (peer-reviewed)abstract
- Current strategies combining anti-angiogenic drugs with chemotherapy provide clinical benefit in cancer patients. It is assumed that anti-angiogenic drugs, such as bevacizumab, transiently normalize abnormal tumor vasculature and contribute to improved delivery of subsequent chemotherapy. To investigate this concept, a study was performed in non-small cell lung cancer (NSCLC) patients using positron emission tomography (PET) and radiolabeled docetaxel ([11C]docetaxel). In NSCLC, bevacizumab reduced both perfusion and net influx rate of [11C]docetaxel within 5 hr. These effects persisted after 4 days. The clinical relevance of these findings is notable, as there was no evidence for a substantial improvement in drug delivery to tumors. These findings highlight the importance of drug scheduling and advocate further studies to optimize scheduling of anti-angiogenic drugs.
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| 20. |
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