Biomarker For Amyotrophic Lateral Sclerosis Research Articles

5'ValCAC tRNA fragment generated as part of a protective angiogenin response provides prognostic value in amyotrophic lateral sclerosis.

Loss-of-function mutations in the ribonuclease angiogenin are associated with amyotrophic lateral sclerosis. Angiogenin has been shown to cleave transfer RNAs during stress to produce ‘transfer-derived stress-induced RNAs’. Stress-induced tRNA cleavage is preserved from single-celled organisms to humans indicating it represents part of a highly conserved stress response. However, to date, the role of tRNA cleavage in amyotrophic lateral sclerosis remains to be fully elucidated. To this end, we performed small RNA sequencing on a human astrocytoma cell line to identify the complete repertoire of tRNA fragments generated by angiogenin. We found that only a specific subset of tRNAs is cleaved by angiogenin and identified 5′ValCAC transfer-derived stress-induced RNA to be secreted from neural cells. 5′ValCAC was quantified in spinal cord and serum from SOD1G93A amyotrophic lateral sclerosis mouse models where we found it to be significantly elevated at symptom onset correlating with increased angiogenin expression, imbalanced protein translation initiation factors and slower disease progression. In amyotrophic lateral sclerosis patient serum samples, we found 5′ValCAC to be significantly higher in patients with slow disease progression, and interestingly, we find 5′ValCAC to hold prognostic value for amyotrophic lateral sclerosis patients. Here, we report that angiogenin cleaves a specific subset of tRNAs and provide evidence for 5′ValCAC as a prognostic biomarker in amyotrophic lateral sclerosis. We propose that increased serum 5′ValCAC levels indicate an enhanced angiogenin-mediated stress response within motor neurons that correlates with increased survival. These data suggest that the previously reported beneficial effects of angiogenin in SOD1G93A mice may result from elevated levels of 5′ValCAC transfer RNA fragment.

Raman spectroscopy reveals biochemical differences in plasma derived extracellular vesicles from sporadic Amyotrophic Lateral Sclerosis patients

Sporadic amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease for which there is no validated blood based biomarker. Extracellular vesicles (EVs) have the potential to solve this unmet clinical need. However, due to their heterogeneity and complex chemical composition, EVs are difficult to study. Raman spectroscopy (RS) is an optical method that seems particularly well suited to address this task. In fact, RS provides an overview of the biochemical composition of EVs quickly and virtually without any sample preparation. In this work, we studied by RS small extracellular vesicles (sEVs), large extracellular vesicles (lEVs) and blood plasma of sporadic ALS patients and of a matched cohort of healthy controls. The obtained results highlighted lEVs as a particularly promising biomarker for ALS. In fact, their Raman spectra show that sporadic ALS patients have a different lipid content and less intense bands relative to the aromatic amino acid phenylalanine.

A prospective longitudinal study on themicrobiota composition in amyotrophic lateral sclerosis

BackgroundA connection between amyotrophic lateral sclerosis (ALS) and alteredgut microbiota composition has previously been reported in animal models. Thiswork is the first prospective longitudinal study addressing the microbiotacomposition in ALS patients and the impact of a probiotic supplementation on thegut microbiota and disease progression.MethodsFifty patients and 50 matched controls were enrolled. The microbialprofile of stool samples from patients and controls was analyzed viaPCR-Denaturing Gradient Gel Electrophoresis, and the main microbial groupsquantified via qPCR. The whole microbiota was then analyzed via next generationsequencing after amplification of the V3–V4 region of 16S rDNA. Patients werethen randomized to receive probiotic treatment or placebo and followed up for6 months with ALSFRS-R, BMI, and FVC%.ResultsThe results demonstrate that the gut microbiota of ALS patients ischaracterized by some differences with respect to controls, regardless of thedisability degree. Moreover, the gut microbiota composition changes during thecourse of the disease as demonstrated by the significant decrease in the numberof observed operational taxonomic unit during the follow-up. Interestingly, anunbalance between potentially protective microbial groups, such asBacteroidetes, and other with potential neurotoxic or pro-inflammatory activity,such as Cyanobacteria, has been shown. The 6-month probiotic treatmentinfluenced the gut microbial composition; however, it did not bring thebiodiversity of intestinal microbiota of patients closer to that of controlsubjects and no influence on the progression of the disease measured by ALSFRS-Rwas demonstrated.ConclusionsOur study poses the bases for larger clinical studies tocharacterize the microbiota changes as a novel ALS biomarker and to test newmicrobial strategy to ameliorate the health status of the gut.Trial registrationCE 107/14, approved by the Ethics Committee of the “Maggiore dellaCarità” University Hospital, Italy.

The Chitinases as Biomarkers for Amyotrophic Lateral Sclerosis: Signals From the CNS and Beyond.

Amyotrophic lateral sclerosis (ALS) is a late-onset neurodegenerative condition, most widely characterized by the selective vulnerability of motor neurons and the poor life expectancy of afflicted patients. Limited disease-modifying therapies currently exist, which only further attests to the substantial heterogeneity associated with this disease. In addition to established prognostic factors like genetic background, site of onset, and age at onset, wide consensus on the role of neuroinflammation as a disease exacerbator and driver has been established. In lieu of this, the emerging literature on chitinases in ALS is particularly intriguing. Individual groups have reported substantially elevated chitotriosidase (CHIT1), chitinase-3-like-1 (CHI3L1), and chitinase-3-like-2 (CHI3L2) levels in the cerebrospinal, motor cortex, and spinal cord of ALS patients with multiple—and often conflicting—lines of evidence hinting at possible links to disease severity and progression. This mini-review, while not exhaustive, will aim to discuss current evidence on the involvement of key chitinases in ALS within the wider framework of other neurodegenerative conditions. Implications for understanding disease etiology, developing immunomodulatory therapies and biomarkers, and other translational opportunities will be considered.

Motor unit number index in children with later-onset spinal muscular atrophy.

Motor unit number index (MUNIX) is a validated electrophysiological biomarker in amyotrophic lateral sclerosis. MUNIX studies in spinal muscular atrophy (SMA) are limited. Later-onset SMA children (n = 13; three SMN2 copy number) were evaluated for Hammersmith Motor Function Scale Expanded (HMFSE) and MUNIX of right abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles. Age-matched healthy controls (n = 8) were enrolled to obtain normative APB and ADM MUNIX values. Mean APB and ADM MUNIX values in SMA subjects were significantly reduced (P < .001) compared with controls. HMFSE scores strongly correlated with ADM MUNIX (r 0.63). APB and ADM muscle MUNIX studies are feasible in SMA type 2 children. ADM MUNIX correlated with disease severity on motor function testing. MUNIX studies in later-onset SMA could be a potential biomarker of motor neuron loss.

Validation of serum neurofilaments as prognostic and potential pharmacodynamic biomarkers for ALS.

To identify preferred neurofilament assays and clinically validate serum neurofilament light (NfL) and phosphorylated neurofilament heavy (pNfH) as prognostic and potential pharmacodynamic biomarkers relevant to amyotrophic lateral sclerosis (ALS) therapy development. In this prospective, multicenter, longitudinal observational study of patients with ALS (n = 229), primary lateral sclerosis (n = 20), and progressive muscular atrophy (n = 11), biological specimens were collected, processed, and stored according to strict standard operating procedures (SOPs). Neurofilament assays were performed in a blinded manner by independent contract research organizations. For serum NfL and pNfH measured using the Simoa assay, there were no missing data (i.e., technical replicates below the lower limit of detection were not encountered). For the Iron Horse and Euroimmun pNfH assays, such missingness was encountered in ∼4% and ∼10% of serum samples, respectively. Mean coefficients of variation for NfL in serum and CSF were both ∼3%. Mean coefficients of variation for pNfH in serum and CSF were ∼4%-5% and ∼2%-3%, respectively, in all assays. Baseline serum NfL concentration, but not pNfH, predicted the future Revised ALS Functional Rating Scale (ALSFRS-R) slope and survival. Incorporation of baseline serum NfL into mixed effects models of ALSFRS-R slopes yields an estimated sample size saving of ∼8%. Depending on the method used to estimate effect size, use of serum NfL (and perhaps pNfH) as pharmacodynamic biomarkers, instead of the ALSFRS-R slope, yields significantly larger sample size savings. Serum NfL may be considered a clinically validated prognostic biomarker for ALS. Serum NfL (and perhaps pNfH), quantified using the Simoa assay, has potential utility as a pharmacodynamic biomarker of treatment effect.

Cerebrospinal fluid MFG-E8 as a promising biomarker of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a fatal progressive neurodegenerative disease resulting in the dysfunction of upper and lower motor neurons. Biomarkers in fluid have been used to monitor the disease and its progression. Milk fat globule-EGF factor 8 (MFG-E8) is an inflammation modulator, which is involved in the pathogenesis of neurodegenerative diseases. We here took this study to evaluate the predictive value of MFG-E8 in ALS. This study consisted of 19 patients with ALS and 15 healthy controls. Cerebrospinal fluid (CSF) were collected from all participants and tested for the levels of MFG-E8, neurofilament light (NFL), and heavy chain (NFH). The correlations between MFG-E8 and NFL, NFH, ALS severity, cognitive status, and forced vital capacity (FVC) were analyzed. We found that MFG-E8 performs well in distinguishing ALS from controls, with relatively higher level of MFG-E8 in ALS subjects, than controls. Moreover, MFG-E8 negatively correlated with the revised ALS function rating scale (ALS-FRS), but not with the levels of NFL and NFH, disease duration, progression rate, mini-mental state examination (MMSE), and FVC. The study proved that CSF MFG-E8 helps distinguish ALS from controls. However, the protein in CSF negatively predicted disease severity.

Mitochondrial Bioenergetic Profile in Platelets as a Biomarker for Amyotrophic Lateral Sclerosis (ALS) (4869)

Mitochondrial Bioenergetic Profile in Platelets as a Biomarker for Amyotrophic Lateral Sclerosis (ALS) (4869)

Plasma creatinine and oxidative stress biomarkers in amyotrophic lateral sclerosis

Objective: To determine the associations between plasma creatinine (PCr), plasma uric acid (PUA), and urinary oxidative stress (OS) biomarkers with the ALSFRS-R at baseline and survival in a large epidemiological cohort study (ALS COSMOS) with a well-phenotyped patient population (N = 355).Methods: Fasting plasma and first void urine samples were obtained. PCr, PUA, urinary 8-oxo-deoxy guanosine (8-oxodG), and 15-F2t-isoprostane (IsoP) were analyzed at baseline, near the midpoint of follow-up, and at the final blood draw (before death or withdrawal from study). We estimated associations between these biomarkers and the ALSFRS-R at baseline and survival.Results: At baseline, PCr correlated with ALSFRS-R (Spearman r = 0.30), percent (%) FVC (r = 0.20), PUA (r = 0.37), and 8-oxodG (r = −0.13, all p < 0.05). Baseline PCr significantly predicted survival (adjusted hazard ratio 0.28, p < 0.001). Time to death from baseline was shortest for those in the lowest two PCr quartiles relative to the highest two quartiles. PCr and ALSFRS-R values were significantly correlated at all three time points (baseline: r = 0.29, midpoint: r = 0.23, final: r = 0.38, all p < 0.001). PCr and PUA significantly declined over time, whereas OS biomarkers significantly increased over time.Conclusions: To date, PCr predicted survival the best, compared to PUA, 8-oxodG, and IsoP. Although PCr represents the degree of muscle mass, it may also represent complex biochemical changes in ALS. Because the field has no reliable prognostic biomarkers, the importance of PCr warrants further investigation through clinical studies in ALS.

MRI study of paraspinal muscles in patients with Amyotrophic Lateral Sclerosis (ALS).

Background: the study of paraspinal muscles is pivotal for the diagnosis and staging of Amyotrophic Lateral Sclerosis (ALS), and is usually performed by electromyography. Objective: to evaluate the role of paraspinal muscle MRI as a diagnostic biomarker in ALS. Methods: we evaluated T1-w images of newly diagnosed ALS patients (n = 14), age-matched healthy controls (n = 11), patients affected by inflammatory myopathy (n = 10), and lumbar radiculopathy (n = 19), and compared them semiquantitatively by using the Mercuri Scale. Results: a significant difference in the appearance of the psoas muscle was observed between ALS patients and patients with radiculopathy (p = 0.003); after stratifying ALS patients into spinal and bulbar onsets, we found a significant difference in the appearance of the longissimus dorsi muscle between the spinal onset ALS subgroup and bulbar onset ALS subgroup (p = 0.0245), while no difference was found for multifidus (p = 0.1441), iliocostal (p = 0.0655), and psoas muscles (p = 0.0813) between the cohort subgroups. Conclusions: paraspinal T1-w MRI could help to distinguish spinal ALS patients from healthy and pathological controls. Specifically, the study of longissimus dorsi could play the role of a diagnostic ALS biomarker.

Usefulness of diffusion tensor imaging findings as biomarkers for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease. However, no reliable biomarkers have been identified to represent the clinical status. This study aimed to investigate whether diffusion tensor imaging (DTI) findings are useful imaging biomarkers to indicate the clinical status of ALS patients. Ninety-six probable or definite ALS cases and 47 age- and sex-matched, normal controls were enrolled. Demographic and clinical data were collected at the time of DTI. DTI data were acquired using a 3-Tesla magnetic resonance imaging scanner and analysed by voxel-wise statistical analyses for fractional anisotropy, axial diffusivity, radial diffusivity, mean diffusivity, and mode of anisotropy. Compared with the healthy control group, the ALS group had significant differences in DTI scalars in the diffuse tracts of the brain, which was predominant in the corticospinal tract at the brainstem and cerebellar peduncle area. Furthermore, the DTI values correlated with the ALS functional rating scale-revised (ALSFRS-R) scores and the delta ALSFRS-R score representing the rate of disease progression. The subgroup analysis revealed a more severe and widespread brain degeneration was observed in rapidly progressive ALS. Therefore, our results suggest that DTI findings are useful as imaging biomarkers for evaluating the clinical severity and rate of disease progression in ALS.

Connectome-Based Propagation Model in Amyotrophic Lateral Sclerosis.

ObjectiveClinical trials in amyotrophic lateral sclerosis (ALS) continue to rely on survival or functional scales as endpoints, despite the emergence of quantitative biomarkers. Neuroimaging‐based biomarkers in ALS have been shown to detect ALS‐associated pathology in vivo, although anatomical patterns of disease spread are poorly characterized. The objective of this study is to simulate disease propagation using network analyses of cerebral magnetic resonance imaging (MRI) data to predict disease progression.MethodsUsing brain networks of ALS patients (n = 208) and matched controls across longitudinal time points, network‐based statistics unraveled progressive network degeneration originating from the motor cortex and expanding in a spatiotemporal manner. We applied a computational model to the MRI scan of patients to simulate this progressive network degeneration. Simulated aggregation levels at the group and individual level were validated with empirical impairment observed at later time points of white matter and clinical decline using both internal and external datasets.ResultsWe observe that computer‐simulated aggregation levels mimic true disease patterns in ALS patients. Simulated patterns of involvement across cortical areas show significant overlap with the patterns of empirically impaired brain regions on later scans, at both group and individual levels. These findings are validated using an external longitudinal dataset of 30 patients.InterpretationOur results are in accordance with established pathological staging systems and may have implications for patient stratification in future clinical trials. Our results demonstrate the utility of computational models in ALS to predict disease progression and underscore their potential as a prognostic biomarker. ANN NEUROL 2020;87:725–738

Circulating RNAs as Potential Biomarkers in Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a complex multi-system neurodegenerative disorder with currently limited diagnostic and no therapeutic options. Despite the intense efforts no clinically applicable biomarkers for ALS are yet established. Most current research is thus focused, in particular, in identifying potential non-invasive circulating biomarkers for more rapid and accurate diagnosis and monitoring of the disease. In this review, we have focused on messenger RNA (mRNA), non-coding RNAs (lncRNAs), micro RNAs (miRNAs) and circular RNA (circRNAs) as potential biomarkers for ALS in peripheral blood serum, plasma and cells. The most promising miRNAs include miR-206, miR-133b, miR-27a, mi-338-3p, miR-183, miR-451, let-7 and miR-125b. To test clinical potential of this miRNA panel, a useful approach may be to perform such analysis on larger multi-center scale using similar experimental design. However, other types of RNAs (lncRNAs, circRNAs and mRNAs) that, together with miRNAs, represent RNA networks, have not been yet extensively studied in blood samples of patients with ALS. Additional research has to be done in order to find robust circulating biomarkers and therapeutic targets that will distinguish key RNA interactions in specific ALS-types to facilitate diagnosis, predict progression and design therapy.

Diagnostic-prognostic value and electrophysiological correlates of CSF biomarkers of neurodegeneration and neuroinflammation in amyotrophic lateral sclerosis.

Neurofilament light chain protein (NfL) is currently the most accurate cerebrospinal fluid (CSF) biomarker in amyotrophic lateral sclerosis (ALS) in terms of both diagnostic and prognostic value, but the mechanism underlying its increase is still a matter of debate. Similarly, emerging CSF biomarkers of neurodegeneration and neuroinflammation showed promising results, although further studies are needed to clarify their clinical and pathophysiological roles. In the present study we compared the diagnostic accuracy of CSF NfL, phosphorylated (p)-tau/total (t)-tau ratio, chitinase-3-like protein 1 (YKL-40) and chitotriosidase 1 (CHIT1), in healthy controls (n = 43) and subjects with ALS (n = 80) or ALS mimics (n = 46). In ALS cases, we also investigated the association between biomarker levels and clinical variables, the extent of upper motor neuron (UMN) and lower motor neuron (LMN) degeneration, and denervation activity through electromyography (EMG). ALS patients showed higher levels of CSF NfL, YKL-40, CHIT1, and lower values of p-tau/t-tau ratio compared to both controls and ALS mimics. Among all biomarkers, NfL yielded the highest diagnostic performance (> 90% sensitivity and specificity) and was the best predictor of disease progression rate and survival in ALS. NfL levels showed a significant correlation with the extent of LMN involvement, whereas YKL-40 levels increased together with the number of areas showing both UMN and LMN damage. EMG denervation activity did not correlate with any CSF biomarker change. These findings confirm the highest value of NfL among currently available CSF biomarkers for the diagnostic and prognostic assessment of ALS and contribute to the understanding of the pathophysiological and electrophysiological correlates of biomarker changes.

Diagnostic and prognostic values of PBMC proteins in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease for which there are no validated biomarkers. Previous exploratory studies have identified a panel of candidate protein biomarkers in peripheral blood mononuclear cells (PBMCs) that include peptidyl-prolyl cis-trans isomerase A (PPIA), heat shock cognate protein 71 kDa (HSC70), heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2B1) and TDP-43. It has also been found that PPIA plays a key role in the assembly and dynamics of ribonucleoprotein (RNP) complexes and interacts with TDP-43. Its absence accelerates disease progression in a SOD1 mouse model of ALS, and low levels of PPIA in PBMCs are associated with early-onset ALS. However, the diagnostic and prognostic values of PPIA and the other candidate protein biomarkers have not been established. We analyzed the PBMC proteins in a well-characterized cohort of ALS patients (n=93), healthy individuals (n=104) and disease controls (n=111). We used a highly controlled sample processing procedure that implies two-step differential detergent fractionation. We found that the levels of the selected PBMC proteins in the soluble and insoluble fraction, combined, have a high discriminatory power for distinguishing ALS from controls, with PPIA, hnRNPA2B1 and TDP-43 being the proteins most closely associated with ALS. We also found a shift toward increased protein partitioning in the insoluble fraction in ALS and this correlated with a worse disease phenotype. In particular, low PPIA soluble levels were associated with six months earlier death. In conclusion, PPIA is a disease modifier with prognostic potential. PBMC proteins indicative of alterations in protein and RNA homeostasis are promising biomarkers of ALS, for diagnosis, prognosis and patient stratification.

Use of Capillary Electrophoresis Immunoassay to Search for Potential Biomarkers of Amyotrophic Lateral Sclerosis in Human Platelets.

Capillary electrophoresis immunoassay (CEI), also known as capillary western technology, is becoming a method of choice for screening disease relevant proteins and drugs in clinical trials. Reproducibility, sensitivity, small sample volume requirement, multiplexing antibodies for multiple protein labeling in the same sample, automated high-throughput ability to analyze up to 24 individual samples, and short time requirement make CEI advantageous over the classical western blot immunoassay. There are some limitations of this method, such as the inability to utilize a gradient gel (4%-20%) matrix, high background with unrefined biological samples, and commercial unavailability of individual reagents. This paper describes an efficient method for running CEI in a multiple assay setting, optimizing protein concentration and primary antibody titration in one assay plate, and providing user-friendly templates for sample preparation. Also described are methods for measuring pan TDP-43 and phosphorylated TDP-43 derivative in platelet lysate cytosol as part of the initiative in blood-based biomarker development for neurodegenerative diseases.

Use of Capillary Electrophoresis Immunoassay to Search for Potential Biomarkers of Amyotrophic Lateral Sclerosis in Human Platelets

Use of Capillary Electrophoresis Immunoassay to Search for Potential Biomarkers of Amyotrophic Lateral Sclerosis in Human Platelets

Multi-dimensional electrical impedance myography of the tongue as a potential biomarker for amyotrophic lateral sclerosis

ObjectiveIn amyotrophic lateral sclerosis (ALS) bulbar disease biomarkers are lacking. We evaluated a novel tongue electrical impedance myography (EIM) system, utilising both 2D and 3D electrode configurations for detection of tongue pathology. MethodsLongitudinal multi-frequency phase angle spectra were recorded from 41 patients with ALS (baseline, 3 and 6 months) and 30 healthy volunteers (baseline and 6 months). ALS functional rating scale-revised (ALSFRS-R) data and quantitative tongue strength measurements were collected. EIM data were analysed for reliability (intra-class correlation coefficient; ICC) and differences between patients and volunteers ascertained using both univariate (Mann-Whitney U test) and multivariate techniques (feature selection and L2 norm). ResultsThe device produced highly reliable data (pooled ICC: 0.836). Significant EIM differences were apparent between ALS patients and healthy volunteers (P < 0.001). EIM data demonstrated a significant relationship to tongue strength and bulbar ALSFRS-R scores (P < 0.015). The EIM recordings revealed a group level longitudinal change over 6 months and consistently identified patients in whom symptoms or tongue strength changed. ConclusionsThe novel EIM tongue system produces reliable data and can differentiate between healthy muscle and ALS-related disease. SignificanceTongue EIM utilising multiple frequencies and electrode configurations has potential as a bulbar disease biomarker in ALS.

Identification of a potential non-coding RNA biomarker signature for amyotrophic lateral sclerosis.

Objective biomarkers for the clinically heterogeneous adult-onset neurodegenerative disorder amyotrophic lateral sclerosis are crucial to facilitate assessing emerging therapeutics and improve the diagnostic pathway in what is a clinically heterogeneous syndrome. With non-coding RNA transcripts including microRNA, piwi-RNA and transfer RNA present in human biofluids, we sought to identify whether non-coding RNA in serum could be biomarkers for amyotrophic lateral sclerosis. Serum samples from our Oxford Study for Biomarkers in motor neurone disease/amyotrophic lateral sclerosis discovery cohort of amyotrophic lateral sclerosis patients (n = 48), disease mimics (n = 16) and age- and sex-matched healthy controls (n = 24) were profiled for non-coding RNA expression using RNA-sequencing, which showed a wide range of non-coding RNA to be dysregulated. We confirmed significant alterations with reverse transcription-quantitative PCR in the expression of hsa-miR-16-5p, hsa-miR-21-5p, hsa-miR-92a-3p, hsa-piR-33151, TRV-AAC4-1.1 and TRA-AGC6-1.1. Furthermore, hsa-miR-206, a previously identified amyotrophic lateral sclerosis biomarker, showed a binary-like pattern of expression in our samples. Using the expression of these non-coding RNA, we were able to discriminate amyotrophic lateral sclerosis samples from healthy controls in our discovery cohort using a random forest analysis with 93.7% accuracy with promise in predicting progression rate of patients. Importantly, cross-validation of this novel signature using a new geographically distinct cohort of samples from the United Kingdom and Germany with both amyotrophic lateral sclerosis and control samples (n = 156) yielded an accuracy of 73.9%. The high prediction accuracy of this non-coding RNA-based biomarker signature, even across heterogeneous cohorts, demonstrates the strength of our approach as a novel platform to identify and stratify amyotrophic lateral sclerosis patients.

Diagnosis of idiopathic amyotrophic lateral sclerosis using Fourier-transform infrared spectroscopic analysis of patient-derived skin.

One of the great challenges in identifying effective therapy in many neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), is the lack of reliable biomarkers. In this study, we applied infrared imaging microspectroscopy, a valuable technique to investigate biomolecule fingerprints and secondary structure of proteins within biological tissue. We hypothesized that, since skin and CNS have the same embryonic origin, spectral differences associated with ALS-specific pathological events will be readily detectable through skin testing using this technique. Cells from healthy individuals and ALS patients were isolated from skin biopsies in order to generate tissue-engineered in vitro skin (TES). Infrared spectra of the generated TES were recorded using a focal-plane-array Fourier transform infrared (FPA-FTIR) spectrometer, and hierarchical cluster analysis of the spectral data was performed in order to establish clear differences between the tested TES specimens. Interestingly, our analyses showed that it was readily possible to discriminate ALS- and control-TES solely based on differences in associated FTIR spectra, mainly located between 1149 and 1473 cm-1, attributed to disruption of phospholipid cell membranes, extracellular matrix remodeling or cholesterol accumulation. Spectral differences within the TES samples may therefore be associated with disease state, paving the way for the identification of biomarkers in ALS.