Comparison of multiplex platforms for cytokine assessments and their potential use for biomarker profiling in multiple sclerosis.

BACKGROUND: The levels of pro and anti-inflammatory cytokines can be altered in different autoimmune pathologies, such as multiple sclerosis (MS). It is likely that cytokines in bodily fluids can provide a good reflection of ongoing disease patho-physiology. In this study we aimed to validate multiplex cytokine platforms and evaluate whether these cytokines are differentially expressed in MS. METHODS: Assay validation for simultaneous quantification of IL-1ß, IL-6, IL-8 and TNF-α in serum and CSF were performed using both the Luminex-xMAP (Luminex) and Meso Scale Discovery (MSD) platforms. Next, the relation of the pro-inflammatory cytokine 4-plex with disease progression, symptoms and subtypes was studied in paired serum and CSF of MS patients (n=56), and compared with healthy controls (n=203), with the use of the MSD-platform. RESULTS: The MSD-platform showed overall better assay characteristics such as, sensitivity, recovery and linearity compared to the Luminex for the 4-plex cytokines in CSF and serum. IL-6, IL-8 and TNF-α (p<0.001) levels were significantly increased in MS serum compared to healthy controls. Moreover, serum IL-1ß levels correlated with expanded disability status scale (EDSS) scores (r=-0.34, p<0.05). Additionally, IL-6 and IL-8 CSF levels were both significantly decreased in MS patients compared to non-inflammatory neurological disease controls. Noteworthy, higher IL-8 CSF levels than IL-8 serum levels were observed for MS patients, indicating intrathecal activation of macrophages in MS. CONCLUSION: We have demonstrated that the pro-inflammatory 4-plex kit of the MSD-platform shows better assay characteristics in comparison with Luminex kit for quantification of these cytokines in serum and CSF. Overall, the increased levels of IL-6, IL-8 and TNF-α in serum of MS patients compared to healthy controls, support the use of multiple cytokines for future MS biomarker and disease progression research.

α-Klotho is unstable in human urine.

α-Klotho is an interesting new biomarker in kidney and cardiovascular disease. As α-Klotho is primarily expressed in renal epithelial tissue, various papers have reported α-Klotho concentrations in urine. As these studies did not address the reliability of urinary α-Klotho measurements and as urine is known to be a complex milieu, we investigated the stability of α-Klotho in both fresh catheter and fresh voided urine. α-Klotho was measured in these fresh urine samples and in the same samples under several other conditions. Storage of fresh catheter urine for 3 h at 37 °C, comparable to storage in the bladder, led to a 82% decrease in α-Klotho concentrations. Compared with fresh voided urine, α-Klotho concentrations decreased on an average of 45 and 82% after storage at -80 °C and -20 °C, respectively. An additional freeze-thaw cycle further decreased α-Klotho concentrations. The addition of a protease inhibitor or 0.1% albumin partly prevented degradation in fresh voided urine. Thus, α-Klotho is highly unstable in urine. Future studies showing results of urinary α-Klotho should mention conservation conditions and prove the reliability of the α-Klotho measurements.

Comparison of 7 Published LC-MS/MS Methods for the Simultaneous Measurement of Testosterone, Androstenedione, and Dehydroepiandrosterone in Serum.

BACKGROUND: Recently, LC-MS/MS was stated to be the method of choice to measure sex steroids. Because information on the mutual agreement of LC-MS/MS methods is scarce, we compared 7 published LC-MS/MS methods for the simultaneous measurement of testosterone, androstenedione, and dehydroepiandrosterone (DHEA). METHODS: We used 7 published LC-MS/MS methods to analyze in duplicate 55 random samples from both men and women. We performed Passing-Bablok regression analysis and calculated Pearson correlation coefficients to assess the agreement of the methods investigated with the median concentration measured by all methods, and we calculated the intraassay CV of each method derived from duplicate results and the CVs between the methods. RESULTS: Median concentrations of testosterone were 0.22-1.36 nmol/L for women and 8.27-27.98 nmol/L for men. Androstenedione and DHEA concentrations were 0.05-5.53 and 0.58-18.04 nmol/L, respectively. Intraassay CVs were 2.9%-10%, 1.2%-8.8%, 2.7%-13%, and 4.3%-16% for testosterone in women, testosterone in men, androstenedione, and DHEA. Slopes of the regression lines calculated by Passing-Bablok regression analysis were 0.92-1.08, 0.92-1.08, 0.90-1.13, and 0.91-1.41 for all testosterone values, testosterone in women, androstenedione, and DHEA. Intermethod CVs were 14%, 8%, 30%, and 22% for testosterone in women, testosterone in men, androstenedione, and DHEA. CONCLUSIONS: In general, the LC-MS/MS methods investigated show reasonable agreement. However, some of the assays show differences in standardization, and others show high variation.

Vitamin D supplementation and testosterone concentrations in male human subjects.

OBJECTIVE: A possible association between serum 25-hydroxyvitamin D and testosterone levels has been reported; however, contradictory results have emerged. DESIGN: To investigate a causal link between vitamin D and testosterone status, we studied the effect of vitamin D supplementation on serum testosterone concentrations in three independent intervention studies including male patients with heart failure (study 1), male nursing home residents (study 2) and male non-Western immigrants in the Netherlands (study 3). METHODS: In study 1, 92 subjects were randomized to either vitamin D (2000 IU cholecalciferol daily) or control. Blood was drawn at baseline, after 3 and 6 weeks. In study 2, 49 vitamin D deficient subjects received either vitamin D (600 IU daily) or placebo. Blood was drawn at baseline, after 8 and 16 weeks. In study 3, 43 vitamin D deficient subjects received either vitamin D (1200 IU daily) or placebo. Blood was drawn at baseline, after 8 and 16 weeks. Serum 25-hydroxyvitamin D levels were measured using LC-MS/MS or radioimmunoassay. Testosterone levels were measured using a 2nd generation immunoassay. RESULTS: Serum 25-hydroxyvitamin D levels significantly increased in all treatment groups (median increase of 27, 30 and 36 nmol/l in studies 1, 2 3, respectively) but not in the control groups. The documented increase in 25-hydroxyvitamin D levels, however, did not affect mean testosterone concentrations at the end of the study (median increase of 0, 0.5 and 0 nmol/l in studies 1, 2 and 3, respectively). CONCLUSIONS: In this post hoc analysis of three small clinical trials of limited duration in men with normal baseline testosterone concentrations, vitamin D supplementation was not associated with an increase in circulating testosterone concentrations.

Apolipoproteins E and J interfere with amyloid-beta uptake by primary human astrocytes and microglia in vitro.

Defective clearance of the amyloid-ß peptide (Aß) from the brain is considered a strong promoter in Alzheimer's disease (AD) pathogenesis. Astrocytes and microglia are important mediators of Aß clearance and Aß aggregation state and the presence of amyloid associated proteins (AAPs), such as Apolipoproteins E and J (ApoE and ApoJ), may influence Aß clearance by these cells. Here we set out to investigate whether astrocytes and microglia differ in uptake efficiency of Aß oligomers (Aßoligo ) and Aß fibrils (Aßfib ), and whether the Aß aggregation state and/or presence of AAPs affect Aß uptake in these cells in vitro. Adult human primary microglia and astrocytes, isolated from short delay post-mortem brain tissue, were exposed to either Aßoligo or Aßfib alone or combined with a panel of certain AAPs whereafter Aß-positive cells were quantified using flow cytometry. Upon exposure to Aß combined with ApoE, ApoJ, α1-antichymotrypsin (ACT) and a combination of serum amyloid P and complement C1q (SAP-C1q), a clear reduction in astrocytic but not microglial Aßoligo uptake, was observed. In contrast, Aßfib uptake was strongly reduced in the presence of AAPs in microglia, but not in astrocytes. These data provide the first evidence of distinct roles of microglia and astrocytes in Aß clearance. More importantly we show that Aß clearance by glial cells is negatively affected by AAPs like ApoE and ApoJ. Thus, targeting the association of Aß with AAPs, such as ApoE and ApoJ, could serve as a therapeutic strategy to increase Aß clearance by glial cells.

First-trimester screening for down syndrome with serum sampling at different gestational ages: the effect on screening performance.

INTRODUCTION: The objective of this study was to evaluate the performance of first-trimester Down syndrome (DS) screening with serum sampling at different weeks of gestation. MATERIAL AND METHODS: We studied 35,431 singleton pregnancies (2005-2011), including 145 DS cases. Screening performance was determined in different maternal age groups with serum sampling between weeks 9 + 0 and 13 + 6. RESULTS: No significant differences were found between the detection rates at different gestational weeks. The false-positive rate (FPR) in week 9 (6%) was comparable to the FPR in week 10 (6.5%; p = 0.214), whereas it was significantly lower compared to weeks 11 (7.2%; p = 0.007), 12 (7.4%; p = 0.003) and 13 (8.5%; p < 0.001). The odds of receiving a false-positive result was significantly increased with serum sampling in week 11 (OR 1.32, 95% CI 1.08-1.63; p = 0.008) for women ≥36 years and from week 12 onwards (OR 1.28, 95% CI 1.01-1.61; p = 0.04) for women <36 years. There were no differences in mean log10 multiple of the median values of pregnancy-associated plasma protein-A, free ß-human chorionic gonadotrophin or nuchal translucency between both age groups, nor in mean maternal age between the different gestational weeks in either age group. DISCUSSION: Early serum sampling (<11 weeks) resulted in higher screening performance. The impact of the increase in the FPR was highest in women ≥36 years.

The cerebrospinal fluid "Alzheimer profile": easily said, but what does it mean?

BACKGROUND: We aimed to identify the most useful definition of the "cerebrospinal fluid Alzheimer profile," based on amyloid-ß1-42 (Aß42), total tau, and phosphorylated tau (p-tau), for diagnosis and prognosis of Alzheimer's disease (AD). METHODS: We constructed eight Alzheimer profiles with previously published combinations, including regression formulas and simple ratios. We compared their diagnostic accuracy and ability to predict dementia due to AD in 1385 patients from the Amsterdam Dementia Cohort. Results were validated in an independent cohort (n = 1442). RESULTS: Combinations outperformed individual biomarkers. Based on the sensitivity of the best performing regression formulas, cutoffs were chosen at 0.52 for the tau/Aß42 ratio and 0.08 for the p-tau/Aß42 ratio. Ratios performed similar to formulas (sensitivity, 91%-93%; specificity, 81%-84%). The same combinations best predicted cognitive decline in mild cognitive impairment patients. Validation confirmed these results, especially regarding the tau/Aß42 ratio. CONCLUSIONS: A tau/Aß42 ratio of >0.52 constitutes a robust cerebrospinal fluid Alzheimer profile. We recommend using this ratio to combine biomarkers.

Maternal segregation of the Dutch preeclampsia locus at 10q22 with a new member of the winged helix gene family.

Preeclampsia is a pregnancy-associated disease with maternal symptoms but placental origin. Epigenetic inheritance is involved in some populations. By sequence analysis of 17 genes in the 10q22 region with maternal effects, we narrowed the minimal critical region linked with preeclampsia in the Netherlands to 444 kb. All but one gene in this region, which lies within a female-specific recombination hotspot, encode DNA- or RNA-binding proteins. One gene, STOX1 (also called C10orf24), contained five different missense mutations, identical between affected sisters, cosegregating with the preeclamptic phenotype and following matrilineal inheritance. Four STOX1 transcripts are expressed in early placenta, including invasive extravillus trophoblast, generating three different isoforms. All contain a winged helix domain related to the forkhead (FOX) family. The largest STOX1 isoform has exclusive nuclear or cytoplasmic expression, indicating activation and inactivation, respectively, of the PI3K-Akt-FOX pathway. Because all 38 FOX proteins and all 8 STOX1 homologs have either tyrosine or phenylalanine at position 153, the predominant Y153H variation is highly mutagenic by conservation criteria but subject to incomplete penetrance. STOX1 is a candidate for preeclampsia controlling polyploidization of extravillus trophoblast.

Laboratory aspects of circulating α-Klotho.

BACKGROUND: α-Klotho is a protein mainly produced in the kidney. Its circulating form has been suggested to link renal damage and distant tissue pathology. As three assays to measure α-Klotho became commercially available, we performed an evaluation of these commercially available Klotho assays. METHODS: We studied within-run variation, between-run variation, matrix effects, linearity, and recovery of added recombinant human Klotho in the α-Klotho assays of IBL (IBL International GmbH, Hamburg, Germany), Cusabio (Cusabio Biotech, Wuhan, China) and USCN (USCN life Science, Inc., Wuhan, China) using both serum and ethylenediaminetetraacetic acid plasma. RESULTS: Within run variation was 4, 13 and 32% for the IBL, Cusabio and USCN assay, respectively. Agreement between serum and EDTA plasma was good in the IBL assay, but poor in the USCN and Cusabio assays however improved after modifications in the Cusabio assay. Standardization and agreement between assays was poor. CONCLUSIONS: The commercially available methods for the measurement of α-Klotho differ in quality. Some of the manufacturers should improve their assays in order to produce accurate results so that reliable conclusions can be drawn from studies in which these assays are used.

ADAM12s and PP13 as first trimester screening markers for adverse pregnancy outcome.

BACKGROUND: The aim of the study was to assess the screening performance of first trimester maternal serum measurements of A-disintegrin-and-metalloprotease 12-s (ADAM12s) and placental protein 13 (PP13) for preeclampsia (PE), gestational hypertension (GH) and small-for-gestational-age (SGA) fetuses. METHODS: In this retrospective case-control study 220 pregnant women were matched for gestational and maternal age at sampling. Results were expressed as multiples of the median (MoM) and compared using Kruskal-Wallis and Mann-Whitney U-test. Screening performance was assessed by receiver operator characteristics (ROC) curves and area under the curve (AUC). RESULTS: Seventeen cases of PE, 30 cases of GH and eight cases of SGA fetuses were matched with 165 controls. ROC-analysis yielded AUCs for ADAM12s and PP13 of 0.63 and 0.59 for PE, 0.68 and 0.57 for GH and 0.59 and 0.62 for SGA, respectively. Combined ADAM12 and PP13 did not improve the AUC value. When the specificity was set at 80%, corresponding detection rate of ADAM12s was 52% for GH. CONCLUSIONS: Combined ADAM12s and PP13 measurements do not predict adverse pregnancy outcome, but decreased first trimester ADAM12s levels are associated with GH.

Challenges in multi-plex and mono-plex platforms for the discovery of inflammatory profiles in neurodegenerative diseases.

Pro and anti-inflammatory cytokines are involved in disease onset and pathophysiology of multiple sclerosis, Alzheimer's disease and Parkinson's disease. It is likely that panels of multiple cytokines provide a good reflection of disease status and can be used as biological markers in body fluids. Different multi-plex platforms, Luminex-xMAP and Meso Scale Discovery, are able to detect multiple analytes in the same sample at the same time. In this literature based review, we offer an overview of the multi-plex platforms and compare them with the golden standard ELISA in their ability to accurately and sensitively detect cytokines in cerebrospinal fluid (CSF) and blood (serum/plasma). The detectability and levels of cytokines in multiple sclerosis, Alzheimer's disease and Parkinson's disease are promising but also show discrepancies between studies. The current immuno-assays lack sensitivity for detection of various cytokines that have low concentrations of cytokines in CSF and blood, and therefore technical improvements are needed. With such improvements the use of large panels of cytokines as inflammatory profiles may offer additional value in diagnosis, prognosis and therapeutic response in neurodegenerative diseases.

Cerebrospinal fluid Aß42 is the best predictor of clinical progression in patients with subjective complaints.

BACKGROUND: The need to recognize Alzheimer's disease (AD) as early as possible led us to evaluate the predictive value of amyloid ß(1-42) (Aß42), total tau (tau), and phosphorylated tau (ptau) in cerebrospinal fluid (CSF) for clinical progression in patients with subjective complaints. METHODS: We recruited nondemented patients with subjective complaints (i.e., criteria for mild cognitive impairment [MCI] not fulfilled) from our memory clinic. We assessed the predictive value of CSF Aß42, tau, and ptau for clinical progression using Cox proportional hazards models adjusted for age, gender, and baseline findings on the Mini-Mental State Examination (MMSE). Clinical progression was defined as progression to MCI or AD. RESULTS: We included 127 patients with subjective complaints (age 60 ± 10 years, 61 [48%] females, MMSE 29 ± 1). At baseline, Aß42 and tau were abnormal in 20 patients (both 16%), and ptau in 32 patients (25%). Thirteen patients (10%) progressed to MCI (n = 11) or AD (n = 2). Aß42 was the strongest predictor of progression to MCI or AD with an adjusted hazard ratio (HR) of 16.0 (3.8-66.4). The adjusted HR associated with tau was 2.8 (0.9-9.2) and with ptau 2.6 (0.8-8.2). Combinations of biomarkers had a lower predictive value than Aß42 alone. CONCLUSION: Low Aß42 was the strongest predictor of clinical progression in patients with subjective complaints. These results are in line with the hypothesis that the cascade of pathologic events starts with deposition of Aß42, whereas neuronal degeneration and hyperphosphorylation of tau are more downstream events, closer to clinical manifestation of AD.

Discriminatory and predictive capabilities of enzyme-linked immunosorbent assay and multiplex platforms in a longitudinal Alzheimer's disease study.

BACKGROUND: Multiplex assays such as xMAP have been proposed for the assessment of Alzheimer's disease (AD) biomarkers amyloid ß 42 (Aß42), tau (Tau), and phosphorylated tau (pTau) in cerebrospinal fluid (CSF). Here, we compared the traditional enzyme-linked immunosorbent assay (ELISA) and xMAP with respect to their: (1) absolute biomarker concentration, (2) ability to distinguish AD from nondemented subjects, (3) ability to monitor AD longitudinally, and (4) ability to predict progression from mild cognitive impairment (MCI) to AD. METHODS: We selected 68 AD, 62 MCI, and 24 nondemented subjects, performed clinical examinations, and obtained CSF at baseline and 2 years later. Aß42, Tau, and pTau were measured with both ELISA and xMAP. RESULTS: Biomarker levels differed considerably between the two assays, and the differences were concentration dependent. No differences were observed in ability to distinguish nondemented subjects from AD patients between ELISA (area under curve of 0.84 for Aß42, 0.79 for Tau, and 0.75 for pTau) and xMAP (area under curve of 0.82 for Aß42, 0.75 for Tau, and 0.73 for pTau), all P < .05. Increased Aß42 levels of AD patients at follow-up compared with baseline were detected with ELISA, whereas increased Tau levels for nondemented subjects and MCI patients were only detected with xMAP. The hazard ratios for progression from MCI to AD did not differ between the assays. CONCLUSION: Both ELISA and multiplex assays can be used to measure AD biomarker levels in CSF to support clinical diagnosis and predict progression from MCI to AD with similar accuracy. Importantly, the assays' output in absolute biomarker concentrations is remarkably different, and this discrepancy cannot be reconciled with simple correction factors.

Cognitive correlates of cerebrospinal fluid biomarkers in frontotemporal dementia.

OBJECTIVE: In this study we investigated the relationships between cerebrospinal fluid (CSF) biomarkers (tau and amyloid-ß1-42 [Aß1-42]) and cognition or behavior in patients with frontotemporal dementia (the behavioral variant, bvFTD). METHODS: We included 58 patients with bvFTD. All patients underwent a neuropsychological assessment and lumbar puncture. Relationships between CSF biomarkers and cognition or behavior were assessed with linear regression analysis. RESULTS: After correction for age, sex, and education, CSF tau levels were found to be negatively related to the Visual Association Test (standardized ß = -0.3, P < .05), whereas CSF Aß1-42 levels were found to be positively related to the Mini-Mental State Examination (ß = 0.3, P < .05), the frontal assessment battery (ß = 0.5, P < .05), and digit span backwards test (ß = 0.3, P = .01). We did not find relations between CSF biomarkers and behavior (measured by the neuropsychiatric inventory). After excluding all patients with a CSF biomarker profile often seen in Alzheimer's disease (high levels of tau and low levels of Aß1-42), we still found relations between CSF Aß1-42 levels and Visual Association Test object naming (ß = 0.4, P < .05), as well as between CSF Aß1-42 levels and the frontal assessment battery (ß = 0.5, P < .05, but there was no relation between CSF tau and cognition. CONCLUSION: Low CSF Aß1-42 levels are associated with worse general cognitive function and worse executive function in patients with bvFTD. Our results provide circumstantial evidence for a pathophysiological role of Aß1-42 in bvFTD.

A prediction model to calculate probability of Alzheimer's disease using cerebrospinal fluid biomarkers.

BACKGROUND: We aimed to develop a prediction model based on cerebrospinal fluid (CSF) biomarkers, that would yield a single estimate representing the probability that dementia in a memory clinic patient is due to Alzheimer's disease (AD). METHODS: All patients suspected of dementia in whom the CSF biomarkers had been analyzed were selected from a memory clinic database. Clinical diagnosis was AD (n = 272) or non-AD (n = 289). The prediction model was developed with logistic regression analysis and included CSF amyloid ß42, CSF phosphorylated tau181, and sex. Validation was performed on an independent data set from another memory clinic, containing 334 AD and 157 non-AD patients. RESULTS: The prediction model estimated the probability that AD is present as follows: p(AD) = 1/(1 + e (- [-0.3315 + score])), where score is calculated from -1.9486 × ln(amyloid ß42) + 2.7915 × ln(phosphorylated tau181) + 0.9178 × sex (male = 0, female = 1). When applied to the validation data set, the discriminative ability of the model was very good (area under the receiver operating characteristic curve: 0.85). The agreement between the probability of AD predicted by the model and the observed frequency of AD diagnoses was very good after taking into account the difference in AD prevalence between the two memory clinics. CONCLUSIONS: We developed a prediction model that can accurately predict the probability of AD in a memory clinic population suspected of dementia based on CSF amyloid ß42, CSF phosphorylated tau181, and sex.

The STOX1 genotype associated with pre-eclampsia leads to a reduction of trophoblast invasion by alpha-T-catenin upregulation.

By using complementary in vitro and ex vivo approaches, we show that the risk allele (Y153H) of the pre-eclampsia susceptibility gene STOX1 negatively regulates trophoblast invasion by upregulation of the cell-cell adhesion protein alpha-T-catenin (CTNNA3). This is effectuated at the crucial epithelial-mesenchymal transition of proliferative into invasive extravillous trophoblast. This STOX1-CTNNA3 interaction is direct and includes Akt-mediated phosphorylated control of nucleo-cytoplasmic shuttling and ubiquitin-mediated degradation as shared with the FOX multigene family. This, to our knowledge, is the first time a genotype associated with pre-eclampsia has been shown to directly limit first trimester extravillous trophoblast invasion, the earliest hallmark of pre-eclampsia.

Accuracy of 6 routine 25-hydroxyvitamin D assays: influence of vitamin D binding protein concentration.

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.

Intraprostatic testosterone and dihydrotestosterone. Part I: concentrations and methods of determination in men with benign prostatic hyperplasia and prostate cancer.

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.

Intraprostatic testosterone and dihydrotestosterone. Part II: concentrations after androgen hormonal manipulation in men with benign prostatic hyperplasia and prostate cancer.

Androgen deprivation therapy (ADT) and 5-α-reductase (5AR) inhibition are used in the treatment of men with advanced or metastatic prostate cancer and benign prostatic hyperplasia (BPH), respectively. These drugs exert their effect by lowering androgen levels in the serum and allegedly, the prostate gland. It is, however, unknown whether (increased) intraprostatic androgen levels are associated with the pathogenesis of BPH and with the initiation and progression of prostate cancer. Also, it is unclear whether intraprostatic dihydrotestosterone (DHT) levels correlate with a response to initial hormonal therapy or with patient outcome. These uncertainties have resulted from the finding that serum testosterone levels do not necessarily reflect those in the prostate gland. Intraprostatic DHT levels of men being treated with 5AR inhibition, of those treated with ADT for hormone-naive prostate cancer, and of those with castration-resistant prostate cancer are all altered in an equivalent manner because of hormonal manipulation. Increased knowledge of the mechanisms of the androgenic steroid pathways in prostatic diseases, with a special focus on intraprostatic androgen levels, may lead to treatment that is tailored to the needs of the individual patient, and probably to new therapeutic targets as well.

EEG abnormalities in early and late onset Alzheimer's disease: understanding heterogeneity.

OBJECTIVE: To compare differences in severity and type of electroencephalography (EEG) abnormalities between early and late onset Alzheimer's disease (AD) and to assess the influence of APOE genotype on this association, in order to understand the biological differences in AD according to age at onset METHOD: Of 460 probable AD patients and 336 patients with subjective complaints, serving as controls, EEG and APOE genotype were obtained. Subjects were categorised by age into a younger (≤65 years) and an older group (>65 years), based on age at diagnosis. Severity and type of EEG abnormalities were visually assessed. Severity of EEG abnormalities ranged from normal to slightly abnormal to moderately severe. EEG abnormalities were characterised as only focal abnormalities, only diffuse abnormalities or both focal and diffuse abnormalities. RESULTS: Logistic regression revealed that younger AD patients more often had EEG abnormalities, which were more severe, with a predominance of both focal and diffuse abnormalities. In controls, we observed the opposite, as older controls more often had EEG abnormalities than younger controls. Furthermore, APOE ε4 negative AD patients had more severe EEG abnormalities than APOE ε4 positive AD patients, while no such effect was observed in controls. There was no interaction between age at onset and APOE ε4 genotype. CONCLUSION: Early onset and APOE ε4 negative AD patients present with more severe EEG abnormalities than late onset and APOE ε4 positive AD patients. These results suggest that in younger patients, AD manifests with more prominent functional brain changes.