BackgroundThe neurofilament light chain (NfL) assay is gradually becoming an essential diagnostic... more BackgroundThe neurofilament light chain (NfL) assay is gradually becoming an essential diagnostic tool for the diagnosis of many neurological diseases including amyotrophic lateral sclerosis (ALS). Different methods for the determination of this biomarker in serum have been developed in recent years.MethodsWe measured blood NfL in 429 patients referred to the tertiary ALS center of Montpellier, France using two different ultrasensitive methods (Ella™ and Simoa™) and we compared the clinical performances of these two approaches. We also converted NfL values into age and body mass index‐adjusted Z‐scores to assess cut‐off values of this biomarker in this clinical context.ResultsWe show comparable diagnostic and prognostic performance of Ella™ and Simoa™ technologies in ALS, with specificities and sensitivities exceeding 80% for both. We propose cut‐off values for serum NfL in this clinical context, thus enabling the routine clinical use of this biomarker.ConclusionThe use of NfL in routine clinical practice will help predict survival and improve diagnostic accuracy by distinguishing ALS from other neurological diseases and motor neuron disease mimics.
BackgroundCerebrospinal fluid (CSF) Aβ1‐42 and the Aβ1‐42/Aβ1‐40 ratio are markers of amyloid pat... more BackgroundCerebrospinal fluid (CSF) Aβ1‐42 and the Aβ1‐42/Aβ1‐40 ratio are markers of amyloid pathology. We aimed to compare their agreement in different neurodegenerative disorders applying different cutoffs.MethodWe included 1564 participants from the Sant Pau Initiative on Neurodegeneration (SPIN), with AD, dementia with Lewy bodies (DLB), frontotemporal lobar degeneration‐related syndromes (FTLD), cognitively impaired but non‐neurodegenerative conditions (others), and cognitively normal individuals (CN). Cutoffs were defined as one‐sided 97.5%, 95% and 90% (Q97.5%, Q95% and Q90%, respectively) quantiles values in a middle‐aged cognitively normal population. These cutoffs for Aβ1‐42 (617 pg/mL, 637 pg/mL and 732 pg/mL, respectively) and Aβ1‐42/Aβ1‐40 (0.060, 0.070 and 0.082, respectively) were used to classify all participants as “positive” or “negative” according to each marker. We compared concordance of Aβ1‐42 and the Aβ1‐42/Aβ1‐40 ratio between groups through X2 test and correlations with Spearman test.ResultCorrelation between Aβ1‐42 and the Aβ1‐42/Aβ1‐40 ratio in CSF was strong (0.71, p<0.001) in the whole cohort, DLB and others groups (0.69 and 0.64, respectively, both p<0.0001); correlation was weak in AD, FTLD and CN groups (0.33, 0.52 and 0.51, respectively, all p<0.0001). Using Q97.5%, Q95% and Q90% cutoffs, Aβ1‐42 and ratio had an overall agreement of 76.6%, 78.3% and 82.9%, respectively in the whole sample. Both measures were normal (« negative ») in 46.1%, 41.6% and 35.8%, and both were abnormal (« positive ») in 30.5%, 36.7% and 47.1% of participants, respectively. Within each diagnostic category, the agreement ranged from 64% (AD) to 91.5% (CN) using Q97.5%, from 69.6% (AD) to 88.7% (CN) using Q95% and from 78.9% (DLB) to 85.9% (AD) using Q90%. Regardless of the cutoff definition, most discordant cases in AD and DLB were due to normal Aβ1‐42 and low ratio, while discordant cases in FTLD were more frequently due to low Aβ1‐42 and normal ratio.ConclusionAlthough Aβ1‐42 and Aβ1‐42/Aβ1‐40 ratio may reflect the same pathophysiological pathway, their agreement depends on cutoff definition. Our results confirm that both parameters show medium to high concordance, and that in case of discordance, Aβ1‐42 positivity with negative ratio is more associated to non‐AD dementias, independently of the cutoff used.
Background: Frontotemporal dementia (FTD) is a progressive, neurodegenerative disorder with clini... more Background: Frontotemporal dementia (FTD) is a progressive, neurodegenerative disorder with clinical and pathological heterogeneity. The main clinical FTD phenotypes are behavioural variant FTD (bvFTD), semantic dementia (SD) and progressive nonfluent aphasia (PNFA). One of the key clinical characteristics of bvFTD is disturbance in eating behaviour, which can be helpful in diagnosing bvFTD and differentiating it from Alzheimer’s disease (AD). The aim of this study was to develop a hypothalamic peptide panel, focusing on measures known to be involved in appetite regulation, to gain a better understanding of the pathophysiology of FTD, and potentially leading to better fluid biomarkers. Methods: A peptide multiplex panel of 13 hypothalamic and 9 peripheral appetite regulating peptides was developed on a liquid chromatography coupled tandemmass spectrometry platform. Concentrations were measured in the CSF of the three clinical FTD phenotypes (bvFTD n1⁄49, SD n1⁄49, PNFA n1⁄44) as well as AD (n1⁄44) and healthy controls (n1⁄46) and compared using non-parametric statistical tests. Results: In five of the hypothalamic peptides there was a significant difference (expressed as pmol/300 ml) between controls and at least one of the FTD groups (p<0.05): neuropeptideW levels were significantly higher in all three groups: bvFTD (0.029), SD (0.034) and PNFA (0.039), controls (0.012); cerebellin was decreased in bvFTD (0.586) and SD (0.591) [controls 0.945], and cocaine-amphetamine regulated transcript was decreased in PNFA (0.359) and SD (0.359) [controls 0.575]; corticotropinreleasing hormone was decreased in bvFTD (0.007) [controls 0.011] and galanin was increased in PNFA (0.107) [controls 0.059]. There was also a trend of decreased levels of pro-orexin in bvFTD. There were also significant differences in two of the peripheral peptides in PNFA (insulin-like growth factor 1 and pancreatic polypeptide). Conclusions: This pilot study shows changes in concentration of a substantial proportion of the hypothalamic peptides within the CSF in the FTD groups compared to controls. Further exploration on a larger clinically defined cohort will enable understanding of the differences in hypothalamic peptides in FTD and investigate whether such a panel could be used as a biomarker in FTD disease diagnosis, prognosis or stratification.
Creutzfeldt–Jakob disease (CJD) is the leading human prion disease and is a major public health c... more Creutzfeldt–Jakob disease (CJD) is the leading human prion disease and is a major public health concern, with the risk of secondary iatrogenic transmission. Screening for CJD is often based on the detection of 14-3-3 protein in cerebrospinal fluid (CSF) through western blot assay and, in a second step, on a more specific method such as RT-QuIC (Real-Time Quaking-Induced Conversion). Alternatives to the detection of 14-3-3 in CSF have recently been proposed, specifically CSF tau proteins, tau/p-tau(181) ratio, and alpha-synuclein. In the present work, we compare the diagnostic performance of these biomarkers with that of 14-3-3 protein in a cohort of suspected CJD patients. Our results indicate that tau detection is the most effective and suitable approach for routine disease detection in a clinical setting. Combination with other biomarkers does not improve overall performance, while the tau/p-tau(181) ratio remains useful for differentiating Alzheimer’s from CJD. In the end, the performance of tau protein detection in CSF reached 78% sensitivity and 80% specificity for the detection of CJD. It is interesting to note that the use of an automated method with a high concentration range allows for rapid and accurate results, which is very useful in clinical practice and allows for confirmatory testing such as RT-QuIC without delay.
International Journal Of Legal Medicine, Jul 27, 2021
The diagnosis of skin wound vitality is currently based on standard histology, but histological f... more The diagnosis of skin wound vitality is currently based on standard histology, but histological findings lack sensitivity in case of a short survival time. New reliable biomarkers of vitality are therefore strongly needed. We assessed the ability of 10 candidate cytokines (IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, TNF-α) to discriminate between vital and early post-mortem wounds. Twenty-four cadavers with a recent open skin wound (< 3 h) were included (20 men, 4 women, mean age = 51.0 ± 24.3 years). An early post-mortem wound was performed in an uninjured skin area, and both wounds were sampled at the autopsy (post-mortem interval (PMI) = 66.3 ± 28.3 h). Needle-puncture sites related to resuscitation cares were included as very early post-mortem wounds (n = 6). In addition to standard histology, cytokines levels were simultaneously measured in each sample using a multiplex sandwich immunoassay, then normalized on healthy skin levels. A quantitative evaluation of IL-8-positive cells in ante- and post-mortem wound samples was also performed. In the training set of samples (n = 72), cytokine levels were significantly higher in vital wounds (mean age = 47 ± 53 min) than in post-mortem wounds (mean PMI = 6.9 ± 9.0 h) (p < 0.2), except for two cytokines (IFN-γ and IL-2). IL-8 was the best discriminatory cytokine (Se = 54%, Sp = 100%, AUC = 0.79), while a multivariate model combining IL-4 and IL12p70 was a bit more discriminant (Se = 55%, Sp = 100%, AUC = 0.84). In the validation set (n = 72), the discriminatory power of the cytokines and the predictive model was slightly lower, with IL-8 remaining the best cytokine (Se = 46%, Sp = 96%, AUC = 0.75). The predictive model remained highly specific (Sp = 100%). Both the cytokines and the predictive model allowed the iatrogenic injuries to be correctly classified as post-mortem wounds. Standard histology and immunohistochemistry showed 21% sensitivity and a specificity of 79% and 100%, respectively. Only two iatrogenic wounds could be properly categorized histologically. This study suggests that cytokines could be useful biomarkers of skin wound vitality and that the immunoassay method could be more sensitive than immunohistochemistry to identify wounds with a short survival time. Further research is underway to confirm these preliminary data.
RR intervals(SDNN) and the square root of the mean of the squares of successive RR intervals diff... more RR intervals(SDNN) and the square root of the mean of the squares of successive RR intervals differences(rMSSD) mean values were significantly lower in patients with AD than in those with MCI or in controls. There were no significant differences between MCI and control groups in mean R-R interval, 5-min total power, VLF, LF and HF or LF/HF ratio. MMSE was negatively correlation with age and duration with illness. HF power emerged as the parameters better related to MMSE. Conclusions: These results suggest that the presence of autonomic cardiac dysfunction in AD patients might be due to a cholinergic deficit in the peripheral autonomic nervous system. The ongoing follow-up of this study population will verify the potential role of the HRV parameters in predicting the degeneration of cognitive functions and mortality rates.
Aim: To compare methods of quantifying serum hepcidin (based on MS and ELISA) and their ability t... more Aim: To compare methods of quantifying serum hepcidin (based on MS and ELISA) and their ability to diagnose true iron deficiency anemia in critically ill patients. Materials & methods: Serum hepcidin was measured in 119 critically ill patients included in the HEPCIDANE clinical trial, using either an ultra-sensitive ELISA kit (from DRG) or two different MS methods. Results: The results show a good correlation between the different methods studied. The Bland–Altman analysis and the Kappa test for clinical groups show a good or very good agreement between the different tests. Conclusion: ELISA or MS show a satisfactory commutability to quantify serum hepcidin. This is of great importance for the determination of therapeutic strategies in iron deficiency.
BackgroundThe neurofilament light chain (NfL) assay is gradually becoming an essential diagnostic... more BackgroundThe neurofilament light chain (NfL) assay is gradually becoming an essential diagnostic tool for the diagnosis of many neurological diseases including amyotrophic lateral sclerosis (ALS). Different methods for the determination of this biomarker in serum have been developed in recent years.MethodsWe measured blood NfL in 429 patients referred to the tertiary ALS center of Montpellier, France using two different ultrasensitive methods (Ella™ and Simoa™) and we compared the clinical performances of these two approaches. We also converted NfL values into age and body mass index‐adjusted Z‐scores to assess cut‐off values of this biomarker in this clinical context.ResultsWe show comparable diagnostic and prognostic performance of Ella™ and Simoa™ technologies in ALS, with specificities and sensitivities exceeding 80% for both. We propose cut‐off values for serum NfL in this clinical context, thus enabling the routine clinical use of this biomarker.ConclusionThe use of NfL in routine clinical practice will help predict survival and improve diagnostic accuracy by distinguishing ALS from other neurological diseases and motor neuron disease mimics.
BackgroundCerebrospinal fluid (CSF) Aβ1‐42 and the Aβ1‐42/Aβ1‐40 ratio are markers of amyloid pat... more BackgroundCerebrospinal fluid (CSF) Aβ1‐42 and the Aβ1‐42/Aβ1‐40 ratio are markers of amyloid pathology. We aimed to compare their agreement in different neurodegenerative disorders applying different cutoffs.MethodWe included 1564 participants from the Sant Pau Initiative on Neurodegeneration (SPIN), with AD, dementia with Lewy bodies (DLB), frontotemporal lobar degeneration‐related syndromes (FTLD), cognitively impaired but non‐neurodegenerative conditions (others), and cognitively normal individuals (CN). Cutoffs were defined as one‐sided 97.5%, 95% and 90% (Q97.5%, Q95% and Q90%, respectively) quantiles values in a middle‐aged cognitively normal population. These cutoffs for Aβ1‐42 (617 pg/mL, 637 pg/mL and 732 pg/mL, respectively) and Aβ1‐42/Aβ1‐40 (0.060, 0.070 and 0.082, respectively) were used to classify all participants as “positive” or “negative” according to each marker. We compared concordance of Aβ1‐42 and the Aβ1‐42/Aβ1‐40 ratio between groups through X2 test and correlations with Spearman test.ResultCorrelation between Aβ1‐42 and the Aβ1‐42/Aβ1‐40 ratio in CSF was strong (0.71, p&lt;0.001) in the whole cohort, DLB and others groups (0.69 and 0.64, respectively, both p&lt;0.0001); correlation was weak in AD, FTLD and CN groups (0.33, 0.52 and 0.51, respectively, all p&lt;0.0001). Using Q97.5%, Q95% and Q90% cutoffs, Aβ1‐42 and ratio had an overall agreement of 76.6%, 78.3% and 82.9%, respectively in the whole sample. Both measures were normal (« negative ») in 46.1%, 41.6% and 35.8%, and both were abnormal (« positive ») in 30.5%, 36.7% and 47.1% of participants, respectively. Within each diagnostic category, the agreement ranged from 64% (AD) to 91.5% (CN) using Q97.5%, from 69.6% (AD) to 88.7% (CN) using Q95% and from 78.9% (DLB) to 85.9% (AD) using Q90%. Regardless of the cutoff definition, most discordant cases in AD and DLB were due to normal Aβ1‐42 and low ratio, while discordant cases in FTLD were more frequently due to low Aβ1‐42 and normal ratio.ConclusionAlthough Aβ1‐42 and Aβ1‐42/Aβ1‐40 ratio may reflect the same pathophysiological pathway, their agreement depends on cutoff definition. Our results confirm that both parameters show medium to high concordance, and that in case of discordance, Aβ1‐42 positivity with negative ratio is more associated to non‐AD dementias, independently of the cutoff used.
Background: Frontotemporal dementia (FTD) is a progressive, neurodegenerative disorder with clini... more Background: Frontotemporal dementia (FTD) is a progressive, neurodegenerative disorder with clinical and pathological heterogeneity. The main clinical FTD phenotypes are behavioural variant FTD (bvFTD), semantic dementia (SD) and progressive nonfluent aphasia (PNFA). One of the key clinical characteristics of bvFTD is disturbance in eating behaviour, which can be helpful in diagnosing bvFTD and differentiating it from Alzheimer’s disease (AD). The aim of this study was to develop a hypothalamic peptide panel, focusing on measures known to be involved in appetite regulation, to gain a better understanding of the pathophysiology of FTD, and potentially leading to better fluid biomarkers. Methods: A peptide multiplex panel of 13 hypothalamic and 9 peripheral appetite regulating peptides was developed on a liquid chromatography coupled tandemmass spectrometry platform. Concentrations were measured in the CSF of the three clinical FTD phenotypes (bvFTD n1⁄49, SD n1⁄49, PNFA n1⁄44) as well as AD (n1⁄44) and healthy controls (n1⁄46) and compared using non-parametric statistical tests. Results: In five of the hypothalamic peptides there was a significant difference (expressed as pmol/300 ml) between controls and at least one of the FTD groups (p<0.05): neuropeptideW levels were significantly higher in all three groups: bvFTD (0.029), SD (0.034) and PNFA (0.039), controls (0.012); cerebellin was decreased in bvFTD (0.586) and SD (0.591) [controls 0.945], and cocaine-amphetamine regulated transcript was decreased in PNFA (0.359) and SD (0.359) [controls 0.575]; corticotropinreleasing hormone was decreased in bvFTD (0.007) [controls 0.011] and galanin was increased in PNFA (0.107) [controls 0.059]. There was also a trend of decreased levels of pro-orexin in bvFTD. There were also significant differences in two of the peripheral peptides in PNFA (insulin-like growth factor 1 and pancreatic polypeptide). Conclusions: This pilot study shows changes in concentration of a substantial proportion of the hypothalamic peptides within the CSF in the FTD groups compared to controls. Further exploration on a larger clinically defined cohort will enable understanding of the differences in hypothalamic peptides in FTD and investigate whether such a panel could be used as a biomarker in FTD disease diagnosis, prognosis or stratification.
Creutzfeldt–Jakob disease (CJD) is the leading human prion disease and is a major public health c... more Creutzfeldt–Jakob disease (CJD) is the leading human prion disease and is a major public health concern, with the risk of secondary iatrogenic transmission. Screening for CJD is often based on the detection of 14-3-3 protein in cerebrospinal fluid (CSF) through western blot assay and, in a second step, on a more specific method such as RT-QuIC (Real-Time Quaking-Induced Conversion). Alternatives to the detection of 14-3-3 in CSF have recently been proposed, specifically CSF tau proteins, tau/p-tau(181) ratio, and alpha-synuclein. In the present work, we compare the diagnostic performance of these biomarkers with that of 14-3-3 protein in a cohort of suspected CJD patients. Our results indicate that tau detection is the most effective and suitable approach for routine disease detection in a clinical setting. Combination with other biomarkers does not improve overall performance, while the tau/p-tau(181) ratio remains useful for differentiating Alzheimer’s from CJD. In the end, the performance of tau protein detection in CSF reached 78% sensitivity and 80% specificity for the detection of CJD. It is interesting to note that the use of an automated method with a high concentration range allows for rapid and accurate results, which is very useful in clinical practice and allows for confirmatory testing such as RT-QuIC without delay.
International Journal Of Legal Medicine, Jul 27, 2021
The diagnosis of skin wound vitality is currently based on standard histology, but histological f... more The diagnosis of skin wound vitality is currently based on standard histology, but histological findings lack sensitivity in case of a short survival time. New reliable biomarkers of vitality are therefore strongly needed. We assessed the ability of 10 candidate cytokines (IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, TNF-α) to discriminate between vital and early post-mortem wounds. Twenty-four cadavers with a recent open skin wound (< 3 h) were included (20 men, 4 women, mean age = 51.0 ± 24.3 years). An early post-mortem wound was performed in an uninjured skin area, and both wounds were sampled at the autopsy (post-mortem interval (PMI) = 66.3 ± 28.3 h). Needle-puncture sites related to resuscitation cares were included as very early post-mortem wounds (n = 6). In addition to standard histology, cytokines levels were simultaneously measured in each sample using a multiplex sandwich immunoassay, then normalized on healthy skin levels. A quantitative evaluation of IL-8-positive cells in ante- and post-mortem wound samples was also performed. In the training set of samples (n = 72), cytokine levels were significantly higher in vital wounds (mean age = 47 ± 53 min) than in post-mortem wounds (mean PMI = 6.9 ± 9.0 h) (p < 0.2), except for two cytokines (IFN-γ and IL-2). IL-8 was the best discriminatory cytokine (Se = 54%, Sp = 100%, AUC = 0.79), while a multivariate model combining IL-4 and IL12p70 was a bit more discriminant (Se = 55%, Sp = 100%, AUC = 0.84). In the validation set (n = 72), the discriminatory power of the cytokines and the predictive model was slightly lower, with IL-8 remaining the best cytokine (Se = 46%, Sp = 96%, AUC = 0.75). The predictive model remained highly specific (Sp = 100%). Both the cytokines and the predictive model allowed the iatrogenic injuries to be correctly classified as post-mortem wounds. Standard histology and immunohistochemistry showed 21% sensitivity and a specificity of 79% and 100%, respectively. Only two iatrogenic wounds could be properly categorized histologically. This study suggests that cytokines could be useful biomarkers of skin wound vitality and that the immunoassay method could be more sensitive than immunohistochemistry to identify wounds with a short survival time. Further research is underway to confirm these preliminary data.
RR intervals(SDNN) and the square root of the mean of the squares of successive RR intervals diff... more RR intervals(SDNN) and the square root of the mean of the squares of successive RR intervals differences(rMSSD) mean values were significantly lower in patients with AD than in those with MCI or in controls. There were no significant differences between MCI and control groups in mean R-R interval, 5-min total power, VLF, LF and HF or LF/HF ratio. MMSE was negatively correlation with age and duration with illness. HF power emerged as the parameters better related to MMSE. Conclusions: These results suggest that the presence of autonomic cardiac dysfunction in AD patients might be due to a cholinergic deficit in the peripheral autonomic nervous system. The ongoing follow-up of this study population will verify the potential role of the HRV parameters in predicting the degeneration of cognitive functions and mortality rates.
Aim: To compare methods of quantifying serum hepcidin (based on MS and ELISA) and their ability t... more Aim: To compare methods of quantifying serum hepcidin (based on MS and ELISA) and their ability to diagnose true iron deficiency anemia in critically ill patients. Materials & methods: Serum hepcidin was measured in 119 critically ill patients included in the HEPCIDANE clinical trial, using either an ultra-sensitive ELISA kit (from DRG) or two different MS methods. Results: The results show a good correlation between the different methods studied. The Bland–Altman analysis and the Kappa test for clinical groups show a good or very good agreement between the different tests. Conclusion: ELISA or MS show a satisfactory commutability to quantify serum hepcidin. This is of great importance for the determination of therapeutic strategies in iron deficiency.
Uploads
Papers by Constance Delaby