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Mattsson N, Rüetschi U, Pijnenburg YAL, Blankenstein MA, Podust VN, Li S, Fagerberg I, Rosengren L, Blennow K, Zetterberg H. Novel cerebrospinal fluid biomarkers of axonal degeneration in frontotemporal dementia. Mol Med Rep 2012; 1:757-61. [PMID: 21479482 DOI: 10.3892/mmr_00000025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Frontotemporal dementia (FTD) is a heterogeneous disease with substantial interpersonal variance in aggressiveness. Novel biomarkers for rapidly progressive FTD could improve diagnosis and provide clues regarding its pathogenesis. In this study, surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry (MS) was used to analyze peptide profiles in cerebrospinal fluid (CSF) from 24 FTD patients. Thirteen patients had rapidly progressive FTD with distinct pathology in a brain MRI after less than 3 years of disease duration. Eleven patients had slowly progressive FTD with a normal brain MRI, but had abnormal findings in SPECT/PET after more than 5 years of disease duration. The axonal damage marker CSF neurofilament light-chain (NF-L) was measured in all subjects to evaluate the amount of axonal degeneration. A CSF NF-L level of 150 ng/l was used as a cut-off point for high NF-L expression. SELDI-TOF analysis of peptides in the range of 2000-20000 m/z revealed one peak with m/z of 6378 that was expressed at a significantly different level (p<0.01) when rapidly versus slowly progressive cases of FTD were compared. Eleven peaks were expressed at different levels when high versus low CSF NF-L were compared. Using chromatographic purification followed by tandem mass spectrometric analysis, five of these peaks were identified as follows: C-terminal fragment of neuroendocrine protein 7B2 (3512.84 Da), C-terminal fragment of osteopontin (7658.19 Da) as well as its mono- and diphosphorylated forms (7738.16 Da and 7818.13 Da, respectively) and pancreatic ribonuclease (14566.33 Da). The peak intensity of pancreatic ribonuclease was higher in patients with low NF-L expression, while the other peptides had a lower peak intensity in this group. Altered levels of these peptides have also been described in other neurodegenerative diseases. Taken together, these data suggest that differentially-expressed peptides are general markers of axonal degeneration. Further studies are needed to verify their prognostic value in FTD.
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Khalil M, Enzinger C, Langkammer C, Ropele S, Mader A, Trentini A, Vane MLG, Wallner-Blazek M, Bachmaier G, Archelos JJ, Koel-Simmelink MJA, Blankenstein MA, Fuchs S, Fazekas F, Teunissen CE. CSF neurofilament and N-acetylaspartate related brain changes in clinically isolated syndrome. Mult Scler 2012; 19:436-42. [PMID: 22917689 PMCID: PMC3652709 DOI: 10.1177/1352458512458010] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: Axonal damage is considered a major cause of disability in multiple sclerosis (MS) and may start early in the disease. Specific biomarkers for this process are of great interest. Objective: To study if cerebrospinal fluid (CSF) biomarkers for axonal damage reflect and predict disease progression already in the earliest stages of the disease, that is, in clinically isolated syndrome (CIS). Methods: We assessed CSF levels of neurofilament heavy (NFH), neurofilament light (NFL) and N-acetylaspartate (NAA) in 67 patients with CIS and 18 controls with neuropsychiatric diseases of non-inflammatory aetiology (NC). Patients with CIS underwent baseline magnetic resonance imaging (MRI) at 3T, and a follow-up MRI after 1 year was obtained in 28 of them. Results: Compared with NC, patients with CIS had higher NFH (p=0.05) and NFL (p<0.001) levels. No significant group differences were found for NAA. Patients’ NFH levels correlated with physical disability (r=0.304, p<0.05) and with change in brain volume over 1 year of follow-up (r=-0.518, p<0.01) but not with change in T2 lesion load. Conclusion: Our results confirm increased neurofilament levels already in CIS being related to the level of physical disability. The association of NFH levels with brain volume but not lesion volume changes supports the association of these markers with axonal damage.
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van Rossum IA, Visser PJ, Knol DL, van der Flier WM, Teunissen CE, Barkhof F, Blankenstein MA, Scheltens P. Injury markers but not amyloid markers are associated with rapid progression from mild cognitive impairment to dementia in Alzheimer's disease. J Alzheimers Dis 2012; 29:319-27. [PMID: 22233766 DOI: 10.3233/jad-2011-111694] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease (AD) is a common cause of mild cognitive impairment (MCI). However, the time between the diagnosis of MCI and the diagnosis of dementia is highly variable. In this study we investigated which known risk factors and biomarkers of AD pathology were associated with rapid progression from MCI to dementia. Of the 203 subjects with MCI, 91 progressed to AD-type dementia and were considered to have MCI-AD at baseline. Subjects with MCI-AD were older, more frequently female and carrier of the APOE-ε4 allele, had lower scores on the Mini-Mental State Examination (MMSE), more medial temporal lobe atrophy (MTA) and lower levels of Aβ1-42 and increased levels of t-tau and p-tau in the cerebrospinal fluid (CSF) compared to subjects without AD-type dementia at follow up. Of the 91 subjects with MCI-AD, we had data available of CSF (n = 56), MTA (n = 76), and APOE-genotype (n = 63). Among the subjects with MCI-AD, MTA (hazard ratio (HR) 2.2, p = 0.004) and low MMSE score (HR 2.0 p = 0.007) were associated with rapid progression to dementia. High CSF t-tau (HR 1.7, p = 0.07) and p-tau (1.7, p = 0.08) tended to be associated with rapid progression to dementia. CSF Aβ1-42, APOE status, age, gender, and educational level were not associated with time to dementia. Our findings implicate a different role for biomarkers in diagnosis and prognosis of MCI-AD. While amyloid markers can be used to identify MCI-AD, injury markers may predict rapid progression to dementia.
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Teunissen CE, Sombekke M, van Winsen L, Killestein J, Barkhof F, Polman CH, Dijkstra CD, Blankenstein MA, Pratico D. Increased plasma 8,12-iso-iPF2alpha- VI levels in relapsing multiple sclerosis patients are not predictive of disease progression. Mult Scler 2012; 18:1092-8. [DOI: 10.1177/1352458511433306] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background: Oxidative stress plays an important role in multiple sclerosis (MS). Isoprostanes are biomarkers for oxidative stress and have been related to neurological disease progression. Objective: To study whether plasma isoprostane levels were related to disease progression in MS. Methods: Plasma levels of 8,12-iso-iPF2alpha-VI were determined in 17 patients with clinically isolated syndrome (CIS), 41 relapsing–remitting MS (RRMS) patients and 5 primary progressive MS (PPMS) patients and related to MRI and clinical disease parameters. Results: Isoprostane levels were similar in CIS (60.9, interquartile range (IQR): 47.7–77.7 pg/ml) and RRMS patients (65.3, IQR: 51.9–82.8 pg/ml). The plasma levels were lower in PPMS patients (42.5, IQR: 37.1–49.9) pg/ml, p<0.05) compared to CIS and RRMS patients in this cohort, which was not confirmed in a second cohort. Baseline isoprostane levels were not related to clinical progression defined by conversion form CIS to RRMS or change in Expanded Disability Status Scale (EDSS) or MS Functional Composite (MSFC) scores during six years of follow-up (CIS + RRMS), nor to change in volume of gadolinium enhancing lesions, T2 lesion load or T1 hypointense lesion load during 2.8 years of follow-up (CIS + RRMS). Conclusion: These results do not support a strong role of 8,12-iso-iPF2alpha-VI in the prediction of disease progression in MS.
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Malekzadeh A, de Groot V, Beckerman H, van Oosten BW, Blankenstein MA, Teunissen C. Challenges in multi-plex and mono-plex platforms for the discovery of inflammatory profiles in neurodegenerative diseases. Methods 2012; 56:508-13. [DOI: 10.1016/j.ymeth.2012.03.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 03/14/2012] [Accepted: 03/16/2012] [Indexed: 01/10/2023] Open
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Giltay EJ, Geleijnse JM, Heijboer AC, de Goede J, Oude Griep LM, Blankenstein MA, Kromhout D. No effects of n-3 fatty acid supplementation on serum total testosterone levels in older men: the Alpha Omega Trial. ACTA ACUST UNITED AC 2012; 35:680-7. [PMID: 22394170 DOI: 10.1111/j.1365-2605.2012.01255.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The intake of the n-3 fatty acids alpha-linolenic acid (ALA), acid (EPA) and docosahexaenoic acid (DHA) has been related to testosterone levels in epidemiological analyses. The aim of this study was to assess whether the n-3 fatty acids affects testosterone levels in post-myocardial infarction (MI) patients, who are at risk of testosterone deficiency. In a double-blind, placebo-controlled trial of low-dose supplementation of n-3 fatty acids, we included 1850 male post-MI patients aged 60-80 years who participated in the Alpha Omega Trial. Patients were randomly allocated to margarines that provided 400 mg/day of EPA-DHA (n = 453), 2 mg/day of ALA (n = 467), EPA-DHA plus ALA (n = 458), or placebo (n = 472). Serum testosterone levels were assessed at baseline and after 41 months using whole day blood samples obtained at the subjects' home or at the hospital. Subjects were on average age of 68.4 (SD 5.3) years old and had baseline mean serum total testosterone of 14.8 (SD 5.6) nmol/L. The four randomized groups did not differ for baseline characteristics. ALA, EPA-DHA, and EPA-DHA plus ALA supplementation did not affect serum total testosterone compared to placebo. Moreover, n-3 fatty acid supplementation did not affect the risk of incident testosterone deficiency (n = 76 with total testosterone <8.0 nmol/L). We conclude that n-3 fatty acids supplementation did not affect serum total testosterone in men who had had a MI.
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Heijboer AC, Blankenstein MA, Kema IP, Buijs MM. Accuracy of 6 Routine 25-Hydroxyvitamin D Assays: Influence of Vitamin D Binding Protein Concentration. Clin Chem 2012; 58:543-8. [DOI: 10.1373/clinchem.2011.176545] [Citation(s) in RCA: 260] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Abstract
BACKGROUND
Recent recognition of its broad pathophysiological importance has triggered an increased interest in 25-hydroxyvitamin D [25(OH)D]. By consequence, throughput in 25(OH)D testing has become an issue for clinical laboratories, and several automated assays for measurement of 25(OH)D are now available. The aim of this study was to test the accuracy and robustness of these assays by comparing their results to those of an isotope dilution/online solid-phase extraction liquid chromatography/tandem mass spectrometry (ID-XLC-MS/MS) method. We put specific focus on the influence of vitamin D–binding protein (DBP) by using samples with various concentrations of DBP.
METHODS
We used 5 automated assays (Architect, Centaur, iSYS, Liaison, and Elecsys), 1 RIA (Diasorin) preceded by extraction, and an ID-XLC-MS/MS method to measure 25(OH)D concentrations in plasma samples of 51 healthy individuals, 52 pregnant women, 50 hemodialysis patients, and 50 intensive care patients. Using ELISA, we also measured DBP concentrations in these samples.
RESULTS
Most of the examined 25(OH)D assays showed significant deviations in 25(OH)D concentrations from those of the ID-XLC-MS/MS method. As expected, DBP concentrations were higher in samples of pregnant women and lower in samples of IC patients compared to healthy controls. In 4 of the 5 fully automated 25(OH)D assays, we observed an inverse relationship between DBP concentrations and deviations from the ID-XLC-MS/MS results.
CONCLUSIONS
25(OH)D measurements performed with most immunoassays suffer from inaccuracies that are DBP concentration dependent. Therefore, when interpreting results of 25(OH)D measurements, careful consideration of the measurement method is necessary.
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Fijneman RJA, de Wit M, Pourghiasian M, Piersma SR, Pham TV, Warmoes MO, Lavaei M, Piso C, Smit F, Delis-van Diemen PM, van Turenhout ST, Terhaar sive Droste JS, Mulder CJJ, Blankenstein MA, Robanus-Maandag EC, Smits R, Fodde R, van Hinsbergh VWM, Meijer GA, Jimenez CR. Proximal fluid proteome profiling of mouse colon tumors reveals biomarkers for early diagnosis of human colorectal cancer. Clin Cancer Res 2012; 18:2613-24. [PMID: 22351690 DOI: 10.1158/1078-0432.ccr-11-1937] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Early detection of colorectal cancer (CRC) and its precursor lesions is an effective approach to reduce CRC mortality rates. This study aimed to identify novel protein biomarkers for the early diagnosis of CRC. EXPERIMENTAL DESIGN Proximal fluids are a rich source of candidate biomarkers as they contain high concentrations of tissue-derived proteins. The FabplCre;Apc(15lox/+) mouse model represents early-stage development of human sporadic CRC. Proximal fluids were collected from normal colon and colon tumors and subjected to in-depth proteome profiling by tandem mass spectrometry. Carcinoembryonic antigen (CEA) and CHI3L1 human serum protein levels were determined by ELISA. RESULTS Of the 2,172 proteins identified, quantitative comparison revealed 192 proteins that were significantly (P < 0.05) and abundantly (>5-fold) more excreted by tumors than by controls. Further selection for biomarkers with highest specificity and sensitivity yielded 52 candidates, including S100A9, MCM4, and four other proteins that have been proposed as candidate biomarkers for human CRC screening or surveillance, supporting the validity of our approach. For CHI3L1, we verified that protein levels were significantly increased in sera from patients with adenomas and advanced adenomas compared with control individuals, in contrast to the CRC biomarker CEA. CONCLUSION These data show that proximal fluid proteome profiling with a mouse tumor model is a powerful approach to identify candidate biomarkers for early diagnosis of human cancer, exemplified by increased CHI3L1 protein levels in sera from patients with CRC precursor lesions.
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Mattsson N, Rosén E, Hansson O, Andreasen N, Parnetti L, Jonsson M, Herukka SK, van der Flier WM, Blankenstein MA, Ewers M, Rich K, Kaiser E, Verbeek MM, Olde Rikkert M, Tsolaki M, Mulugeta E, Aarsland D, Visser PJ, Schröder J, Marcusson J, de Leon M, Hampel H, Scheltens P, Wallin A, Eriksdotter-Jönhagen M, Minthon L, Winblad B, Blennow K, Zetterberg H. Age and diagnostic performance of Alzheimer disease CSF biomarkers. Neurology 2012; 78:468-76. [PMID: 22302554 DOI: 10.1212/wnl.0b013e3182477eed] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES Core CSF changes in Alzheimer disease (AD) are decreased amyloid β(1-42), increased total tau, and increased phospho-tau, probably indicating amyloid plaque accumulation, axonal degeneration, and tangle pathology, respectively. These biomarkers identify AD already at the predementia stage, but their diagnostic performance might be affected by age-dependent increase of AD-type brain pathology in cognitively unaffected elderly. METHODS We investigated effects of age on the diagnostic performance of CSF biomarkers in a uniquely large multicenter study population, including a cross-sectional cohort of 529 patients with AD dementia (median age 71, range 43-89 years) and 304 controls (67, 44-91 years), and a longitudinal cohort of 750 subjects without dementia with mild cognitive impairment (69, 43-89 years) followed for at least 2 years, or until dementia diagnosis. RESULTS The specificities for subjects without AD and the areas under the receiver operating characteristics curves decreased with age. However, the positive predictive value for a combination of biomarkers remained stable, while the negative predictive value decreased only slightly in old subjects, as an effect of the high AD prevalence in older ages. CONCLUSION Although the diagnostic accuracies for AD decreased with age, the predictive values for a combination of biomarkers remained essentially stable. The findings highlight biomarker variability across ages, but support the use of CSF biomarkers for AD even in older populations.
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Kester MI, van der Flier WM, Visser A, Blankenstein MA, Scheltens P, Oudejans CB. Decreased mRNA expression of CCL5 [RANTES] in Alzheimer's disease blood samples. Clin Chem Lab Med 2012; 50:61-5. [DOI: 10.1515/cclm.2011.731] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 09/05/2011] [Indexed: 11/15/2022]
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Mulder SD, Veerhuis R, Blankenstein MA, Nielsen HM. The effect of amyloid associated proteins on the expression of genes involved in amyloid-β clearance by adult human astrocytes. Exp Neurol 2012; 233:373-9. [DOI: 10.1016/j.expneurol.2011.11.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Revised: 10/25/2011] [Accepted: 11/01/2011] [Indexed: 11/24/2022]
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Schoonenboom NSM, Reesink FE, Verwey NA, Kester MI, Teunissen CE, van de Ven PM, Pijnenburg YAL, Blankenstein MA, Rozemuller AJ, Scheltens P, van der Flier WM. Cerebrospinal fluid markers for differential dementia diagnosis in a large memory clinic cohort. Neurology 2011; 78:47-54. [PMID: 22170879 DOI: 10.1212/wnl.0b013e31823ed0f0] [Citation(s) in RCA: 211] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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63
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Goos JDC, Teunissen CE, Veerhuis R, Verwey NA, Barkhof F, Blankenstein MA, Scheltens P, van der Flier WM. Microbleeds relate to altered amyloid-β metabolism in Alzheimer's disease. Neurobiol Aging 2011; 33:1011.e1-9. [PMID: 22118945 DOI: 10.1016/j.neurobiolaging.2011.10.026] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 10/21/2011] [Accepted: 10/23/2011] [Indexed: 10/14/2022]
Abstract
Cerebral microbleeds (MBs) may relate to amyloid in dementia. We selected 26 probable Alzheimer's disease (AD) patients with MBs, 26 age- and sex-matched AD patients without MBs, 11 vascular dementia (VaD) patients, and 22 patients with subjective complaints. We measured amyloid beta 1-42 (Aβ42) and 1-40 (Aβ40) in cerebrospinal fluid (CSF) and plasma, and blood-brain barrier (BBB) function using albumin ratios. CSF Aβ42 was lowest in AD with MBs, whereas Aβ40 was selectively decreased in VaD. In plasma, amyloid-beta was nonsignificantly elevated in VaD compared with controls. Higher albumin ratios in VaD suggested blood-brain barrier dysfunction. A MB pattern suggestive of cerebral amyloid angiopathy (CAA) related to lower CSF Aβ42, while a non-cerebral amyloid angiopathy specific MB distribution related to higher plasma Aβ40. Amyloid-beta is differentially implicated in AD with MBs and VaD. MB distribution related to different amyloid profiles, supporting distinct etiologies. Our results suggest that Aβ42 is retained in cerebrovasculature of AD patients with MBs, while in contrast, VaD patients may possibly drain amyloid.
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Engels MAJ, Heijboer AC, Blankenstein MA, van Vugt JMG. Performance of first-trimester combined test for Down syndrome in different maternal age groups: reason for adjustments in screening policy? Prenat Diagn 2011; 31:1241-5. [PMID: 22025131 DOI: 10.1002/pd.2873] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 07/02/2011] [Accepted: 07/04/2011] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To evaluate the performance of the first-trimester combined test (FCT) in different maternal age groups and to discuss whether adjustments in screening policies should be made. METHODS In this retrospective study data (n = 26 274) from a fetal medicine center on FCT (maternal age, fetal NT, free β-human chorionic gonadotrophin, pregnancy-associated plasma protein-A) were studied. RESULTS 70.6% of cases was <36 years and 43% of the Down syndrome (DS) cases were detected in this age group. For women <36 years and advanced maternal age (AMA) women (≥36 years) detection rate (DR) and false positive rate (FPR) were 94.5% and 4.1%, and 95.8% and 13.0%, respectively (cut-off 1:200). Lowering the cut-off showed an improved balance in DR and FPR. With increasing maternal age FPR and DR increased and odds of being affected given a positive result (OAPR) decreased. CONCLUSION FCT is effective in women <36 and ≥36 years. The balance between FPR and DR is more favourable in women <36 years with comparable OAPR. Although FPR increases with increasing maternal age, performance of FCT in AMA women is more effective than screening based on maternal age alone. Lowering the cut-off to 1:100 in AMA women is suggested to improve screening performance. Routinely offering diagnostic testing to AMA women as a screening policy for the detection of DS seems not reasonable.
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van der Sluis TM, Meuleman EJ, van Moorselaar RJA, Bui HN, Blankenstein MA, Heijboer AC, Vis AN. Intraprostatic testosterone and dihydrotestosterone. Part II: concentrations after androgen hormonal manipulation in men with benign prostatic hyperplasia and prostate cancer. BJU Int 2011; 109:183-8. [DOI: 10.1111/j.1464-410x.2011.10652.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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66
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van der Sluis TM, Vis AN, van Moorselaar RJA, Bui HN, Blankenstein MA, Meuleman EJH, Heijboer AC. Intraprostatic testosterone and dihydrotestosterone. Part I: concentrations and methods of determination in men with benign prostatic hyperplasia and prostate cancer. BJU Int 2011; 109:176-82. [PMID: 21992222 DOI: 10.1111/j.1464-410x.2011.10651.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Owing to inconsistencies and methodological differences, the present peer-reviewed literature lacks conclusive data on the intraprostatic levels of androgens, in particular dihydrotestosterone (DHT), in untreated benign prostatic hyperplasia (BPH) and prostate cancer. To date, no difference has been shown between DHT concentrations in normal prostatic tissue and BPH, and nor has a difference been shown in DHT concentrations between the histologically distinct regions of the prostate. Recent literature has also failed to show a consistent difference in androgen level between BPH and prostate cancer. The role of intraprostatic DHT in the pathogenesis of BPH and in the initiation and progression of prostate cancer thus remains to be established. Increased knowledge of the mechanisms of the androgenic steroid pathways in prostatic diseases, with a special focus on intraprostatic androgen levels may lead to more optimized and more personalized forms of treatment, and probably new therapeutic targets as well.
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Koel-Simmelink MJA, Teunissen CE, Behradkia P, Blankenstein MA, Petzold A. The neurofilament light chain is not stable in vitro. Ann Neurol 2011; 69:1065-6; author reply 1066-7. [PMID: 21681804 DOI: 10.1002/ana.22438] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Heijboer AC, Martens F, Mulder SD, Schats R, Blankenstein MA. Interference in human chorionic gonadotropin (hCG) analysis by macro-hCG. Clin Chim Acta 2011; 412:2349-50. [PMID: 21851812 DOI: 10.1016/j.cca.2011.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 08/03/2011] [Accepted: 08/03/2011] [Indexed: 11/18/2022]
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Kester MI, Verwey NA, van Elk EJ, Blankenstein MA, Scheltens P, van der Flier WM. Progression from MCI to AD: Predictive value of CSF Aβ42 is modified by APOE genotype. Neurobiol Aging 2011; 32:1372-8. [DOI: 10.1016/j.neurobiolaging.2009.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 07/21/2009] [Accepted: 08/17/2009] [Indexed: 10/20/2022]
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Teunissen C, Goos J, Veerhuis R, Barkhof F, Scheltens P, Blankenstein MA, Van der Flier W. O2‐06‐04: Amyloid and Microbleeds in different dementias: retained or drained? Alzheimers Dement 2011. [DOI: 10.1016/j.jalz.2011.05.877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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71
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Harten A, Visser PJ, Scheltens P, Van der Flier W, Pijnenburg Y, Blankenstein MA. O1‐04‐04: CSF biomarkers predict progression in patients with subjective memory complaints. Alzheimers Dement 2011. [DOI: 10.1016/j.jalz.2011.05.251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mattsson N, Andreasson U, Persson S, Arai H, Batish SD, Bernardini S, Bocchio-Chiavetto L, Blankenstein MA, Carrillo MC, Chalbot S, Coart E, Chiasserini D, Cutler N, Dahlfors G, Duller S, Fagan AM, Forlenza O, Frisoni GB, Galasko D, Galimberti D, Hampel H, Handberg A, Heneka MT, Herskovits AZ, Herukka SK, Holtzman DM, Humpel C, Hyman BT, Iqbal K, Jucker M, Kaeser SA, Kaiser E, Kapaki E, Kidd D, Klivenyi P, Knudsen CS, Kummer MP, Lui J, Lladó A, Lewczuk P, Li QX, Martins R, Masters C, McAuliffe J, Mercken M, Moghekar A, Molinuevo JL, Montine TJ, Nowatzke W, O'Brien R, Otto M, Paraskevas GP, Parnetti L, Petersen RC, Prvulovic D, de Reus HPM, Rissman RA, Scarpini E, Stefani A, Soininen H, Schröder J, Shaw LM, Skinningsrud A, Skrogstad B, Spreer A, Talib L, Teunissen C, Trojanowski JQ, Tumani H, Umek RM, Van Broeck B, Vanderstichele H, Vecsei L, Verbeek MM, Windisch M, Zhang J, Zetterberg H, Blennow K. The Alzheimer's Association external quality control program for cerebrospinal fluid biomarkers. Alzheimers Dement 2011; 7:386-395.e6. [PMID: 21784349 PMCID: PMC3710290 DOI: 10.1016/j.jalz.2011.05.2243] [Citation(s) in RCA: 301] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 05/06/2011] [Indexed: 11/19/2022]
Abstract
BACKGROUND The cerebrospinal fluid (CSF) biomarkers amyloid β (Aβ)-42, total-tau (T-tau), and phosphorylated-tau (P-tau) demonstrate good diagnostic accuracy for Alzheimer's disease (AD). However, there are large variations in biomarker measurements between studies, and between and within laboratories. The Alzheimer's Association has initiated a global quality control program to estimate and monitor variability of measurements, quantify batch-to-batch assay variations, and identify sources of variability. In this article, we present the results from the first two rounds of the program. METHODS The program is open for laboratories using commercially available kits for Aβ, T-tau, or P-tau. CSF samples (aliquots of pooled CSF) are sent for analysis several times a year from the Clinical Neurochemistry Laboratory at the Mölndal campus of the University of Gothenburg, Sweden. Each round consists of three quality control samples. RESULTS Forty laboratories participated. Twenty-six used INNOTEST enzyme-linked immunosorbent assay kits, 14 used Luminex xMAP with the INNO-BIA AlzBio3 kit (both measure Aβ-(1-42), P-tau(181P), and T-tau), and 5 used Meso Scale Discovery with the Aβ triplex (AβN-42, AβN-40, and AβN-38) or T-tau kits. The total coefficients of variation between the laboratories were 13% to 36%. Five laboratories analyzed the samples six times on different occasions. Within-laboratory precisions differed considerably between biomarkers within individual laboratories. CONCLUSIONS Measurements of CSF AD biomarkers show large between-laboratory variability, likely caused by factors related to analytical procedures and the analytical kits. Standardization of laboratory procedures and efforts by kit vendors to increase kit performance might lower variability, and will likely increase the usefulness of CSF AD biomarkers.
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Mulder SD, Hack CE, van der Flier WM, Scheltens P, Blankenstein MA, Veerhuis R. Evaluation of intrathecal serum amyloid P (SAP) and C-reactive protein (CRP) synthesis in Alzheimer's disease with the use of index values. J Alzheimers Dis 2011; 22:1073-9. [PMID: 20930309 DOI: 10.3233/jad-2010-100888] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Serum amyloid P (SAP) and C-reactive protein (CRP) are proteins involved in innate immunity. The expression of SAP and CRP is increased in Alzheimer's disease (AD) brain tissue, compared to healthy controls. Although both proteins are found in cerebrospinal fluid (CSF), their origin is unclear. We investigated if increased local production of SAP and CRP in AD brain results in higher levels in CSF with the use of index values. To study this, SAP, CRP, and albumin levels were determined in CSF and serum samples of 30 control (65 ± 11 years; 57% female) and 140 AD subjects (65 ± 9 years; 53% female). To correct for inter-individual differences in protein diffusion from blood to CSF, quotients (Q =CSF/serum) of SAP, CRP, and albumin and index values (Qprotein/Qalb) were calculated. The results showed no significant differences in SAP and CRP index values between control and AD subjects, although eight percent of individual AD patients showed evidence of intrathecal SAP or CRP production using the Reiber hyperbolic model. Interestingly, the SAP index value was much lower than expected, based on its molecular size. In conclusion, these data suggest that local production of SAP and CRP in the AD brain does not substantially contribute to the CSF levels.
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Heijboer AC, Frans A, Lomecky M, Blankenstein MA. Analysis of glucagon-like peptide 1; what to measure? Clin Chim Acta 2011; 412:1191-4. [PMID: 21414305 DOI: 10.1016/j.cca.2011.03.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 03/09/2011] [Accepted: 03/09/2011] [Indexed: 11/26/2022]
Abstract
BACKGROUND Glucagon-like peptide 1 (GLP-1) is a gut hormone which acts as an incretin and is therefore of major interest in treatment of type II diabetes mellitus. GLP-1 circulates in many different forms, some of which are biologically active and others are not. Our hypothesis was that various methods to measure GLP-1 detect different forms of GLP-1, which may cause confusion when comparing results. METHODS We compared three assays, the GLP-1 (active) ELISA (Linco research; ELISA(LINCO)), GLP-1 (total) RIA (Linco research; RIA(LINCO)) and the total GLP-1 RIA developed by the group of Holst (RIA(HOLST)) on specimens obtained during meal studies. In addition, we studied the effect of addition of a DPP-4 inhibitor. RESULTS The correlation between RIA(LINCO) and ELISA(LINCO) was highest (r=0.76; n=35; p<0.01), whereas results of RIA(HOLST) correlated less with those of RIA(LINCO) and ELISA(LINCO) (r=0.35 and 0.39 respectively; n=35; p<0.05). GLP-1 results measured with ELISA(LINCO) were higher (median 28%; p<0.001) upon addition of the DPP-4 inhibitor. CONCLUSION Two commercially available GLP-1 assays do not necessarily give results equal to the well-defined GLP-1 assay developed in Copenhagen. Absolute values are also different due to differences in standardisation. Moreover, assays detect different forms of GLP-1, which hampers comparison to published data.
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van Harten AC, Kester MI, Visser PJ, Blankenstein MA, Pijnenburg YAL, van der Flier WM, Scheltens P. Tau and p-tau as CSF biomarkers in dementia: a meta-analysis. Clin Chem Lab Med 2011; 49:353-66. [PMID: 21342021 DOI: 10.1515/cclm.2011.086] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND To evaluate the value of total tau (tau) and phosphorylated tau (p-tau) in cerebrospinal fluid (CSF) in the differential diagnosis of dementia, more specifically: dementia with Lewy Bodies (DLB), frontotemporal lobar degeneration (FTLD), vascular dementia (VaD), and Creutzfeldt-Jacob disease (CJD). METHODS A systematic literature search was performed to identify studies on tau and p-tau in DLB, FTLD, VaD and CJD. Tau concentrations were compared to healthy controls and to subjects with Alzheimer's disease (AD) using random effect meta-analysis. Outcome measures were Cohen's delta, sensitivity and specificity. RESULTS Compared to controls, tau concentrations are moderately elevated in DLB, FTLD and VaD, while p-tau concentrations are only slightly elevated in DLB and not elevated in FTLD and VaD. Compared to AD, lower tau concentrations differentiated DLB with a sensitivity of 73% and a specificity of 90%, FTLD with sensitivity and specificity of 74%, and VaD with a sensitivity of 73% and a specificity of 86%. Relative to AD, lower p-tau values differentiated FTLD with a sensitivity of 79% and specificity of 83%, and VaD with a sensitivity of 88% and a specificity of 78%. CJD is characterized by extremely elevated tau concentrations with a sensitivity of 91% and a specificity of 98% vs. AD. CONCLUSIONS CSF tau concentrations in DLB, FTLD and VaD are intermediate between controls and AD patients. Overlap with both controls and AD patients results in insufficient diagnostic accuracy, and the development of more specific biomarkers for these disorders is needed. CJD is characterized by extremely increased tau values, resulting in a sensitivity and specificity that exceeds 90%.
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