Kristian Winge

Amyloid-related biomarkers and axonal damage proteins in parkinsonian syndromes

BACKGROUND Clinical differentiation between parkinsonian syndromes (PS) remains a challenge despite well-established clinical diagnostic criteria. Specific diagnostic biomarkers have yet to be identified, though in recent years, studies have been published on the aid of certain brain related proteins (BRP) in the diagnosing of PS. We investigated the levels of the light subunit of neurofilament triplet protein (NF-L), total tau and phosphorylated tau, amyloid-β(1-42), and the soluble α- and β-cleaved fragments of amyloid precursor proteins in a cohort of patients with various PS. METHODS Seventy-one patients with different PS and cerebellar disorders were included consecutively over 21 months. CSF was collected at inclusion. Clinical follow-up was performed after 16 months (median; range: 9-30). Statistical comparison was performed after follow-up on 53 patients in four subgroups of PS: multiple system atrophy (MSA)(n = 10), progressive supranuclear palsy (PSP)(n = 10), dementia with Lewy bodies (DLB)(n = 11), and Parkinsons disease (PD)(n = 22), using the non-parametric Kruskal-Wallis test. RESULTS A statistically significant difference was found for NF-L (p < 0.0001, lowest values for PD), Aβ(1-42,) (p = 0.002, lowest values for DLB), and sAPPα and sAPPβ (p = 0.03 and 0.02, lower values observed for DLB and MSA). CONCLUSION We demonstrate a potential role for sAPPα and sAPPβ in distinguishing between PS, a finding that needs to be confirmed in future studies of larger cohorts. There is a tendency towards low levels of Aβ(1-42) in DLB patients in our cohort. Further, our results support findings from previous studies, which indicate an ability to separate atypical PS from PD based on levels of NF-L.

Changes in total cell numbers of the basal ganglia in patients with multiple system atrophy — A stereological study

Total numbers of neurons, oligodendrocytes, astrocytes, and microglia in the basal ganglia and red nucleus were estimated in brains from 11 patients with multiple system atrophy (MSA) and 11 age- and gender-matched control subjects with unbiased stereological methods. Compared to the control subjects, the MSA patients had a substantially lower number of neurons in the substantia nigra (p=0.001), putamen (p=0.001), and globus pallidus (p<0.001), and, to a lesser extent in the caudate nucleus (p=0.03). A significantly lower number of oligodendrocytes were only observed in the putamen (p=0.04) and globus pallidus (p=0.01). In the MSA brains the total number of astrocytes was significantly higher in the putamen (p=0.04) and caudate nucleus (p=0.01). In all examined regions a higher number of microglia were found in the MSA brains with the greatest difference observed in the otherwise unaffected red nucleus (p=0.001). The results from the stereological study were supported by cell marker expression analyses showing increased markers for activated microglia. Our results suggest that microgliosis is a consistent and severe neuropathological feature of MSA, whereas no widespread and substantial loss of oligodendrocytes was observed. We have demonstrated significant neuronal loss in the substantia nigra, striatum, and globus pallidus of patients with MSA, while neurons in other basal ganglia nuclei were spared, supporting the region-specific patterns of neuropathological changes in MSA.

Fluid biomarkers in multiple system atrophy: A review of the MSA Biomarker Initiative

Despite growing research efforts, no reliable biomarker currently exists for the diagnosis and prognosis of multiple system atrophy (MSA). Such biomarkers are urgently needed to improve diagnostic accuracy, prognostic guidance and also to serve as efficacy measures or surrogates of target engagement for future clinical trials. We here review candidate fluid biomarkers for MSA and provide considerations for further developments and harmonization of standard operating procedures. A PubMed search was performed until April 24, 2015 to review the literature with regard to candidate blood and cerebrospinal fluid (CSF) biomarkers for MSA. Abstracts of 1760 studies were retrieved and screened for eligibility. The final list included 60 studies assessing fluid biomarkers in patients with MSA. Most studies have focused on alpha-synuclein, markers of axonal degeneration or catecholamines. Their results suggest that combining several CSF fluid biomarkers may be more successful than using single markers, at least for the diagnosis. Currently, the clinically most useful markers may comprise a combination of the light chain of neurofilament (which is consistently elevated in MSA compared to controls and Parkinsons disease), metabolites of the catecholamine pathway and proteins such as α-synuclein, DJ-1 and total-tau. Beyond future efforts in biomarker discovery, the harmonization of standard operating procedures will be crucial for future success.

Screening of Toll-like receptors expression in multiple system atrophy brains.

The family of Toll-like receptors (TLRs) plays a key role in controlling innate immune responses to a wide variety of pathogen-associated molecules. It was recently suggested that TLRs have an important role in the crosstalk between neurons and glial cells in the central nervous system, thus their deregulation may play a role in neurodegeneration. Multiple system atrophy (MSA) together with Parkinson’s disease belongs to a diverse group of neurodegenerative conditions termed α-synucleinopathies. MSA is a fatal late onset disease characterized by the presence of α-synuclein positive glial cytoplasmic inclusions in oligodendrocytes. α-Synuclein can act as a danger-associated molecular pattern and alter TLR expression thereby activating inflammatory responses in the brain. In this study, using real-time PCR, we assessed the expression of TLRs (TLR1-10) in selected areas of MSA brains (substantia nigra, striatum, cerebral cortex, and nucleus dentatus) in comparison with normal controls. We show evidence for increased levels of mRNA-encoding hTLR-3, hTLR-4, and hTLR-5 in substantia nigra, striatum, cerebral cortex, and nucleus dentatus from MSA brains versus normal controls. The levels of expression of hTLR-1 mRNA were elevated in substantia nigra and striatum whereas levels of hTLR-8 and hTLR-9 mRNAs were significantly higher in cerebella from MSA patients. The concerted alteration of expression of multiple TLRs in MSA brains can be of relevance for understanding the pathogenesis of the disease.

Assessment of brain reference genes for RT-qPCR studies in neurodegenerative diseases

Evaluation of gene expression levels by reverse transcription quantitative real-time PCR (RT-qPCR) has for many years been the favourite approach for discovering disease-associated alterations. Normalization of results to stably expressed reference genes (RGs) is pivotal to obtain reliable results. This is especially important in relation to neurodegenerative diseases where disease-related structural changes may affect the most commonly used RGs. We analysed 15 candidate RGs in 98 brain samples from two brain regions from Alzheimer’s disease (AD), Parkinson’s disease (PD), Multiple System Atrophy, and Progressive Supranuclear Palsy patients. Using RefFinder, a web-based tool for evaluating RG stability, we identified the most stable RGs to be UBE2D2, CYC1, and RPL13 which we recommend for future RT-qPCR studies on human brain tissue from these patients. None of the investigated genes were affected by experimental variables such as RIN, PMI, or age. Findings were further validated by expression analyses of a target gene GSK3B, known to be affected by AD and PD. We obtained high variations in GSK3B levels when contrasting the results using different sets of common RG underlining the importance of a priori validation of RGs for RT-qPCR studies.

Neocortical Neuronal Loss in Patients with Multiple System Atrophy: A Stereological Study

Abstract To determine the extent of neocortical involvement in multiple system atrophy (MSA), we used design‐based stereological methods to estimate the total numbers of neurons, oligodendrocytes, astrocytes, and microglia in the frontal, parietal, temporal, and occipital cortex of brains from 11 patients with MSA and 11 age‐ and gender‐matched control subjects. The stereological data were supported by cell marker expression analyses in tissue samples from the prefrontal cortex. We found significantly fewer neurons in the frontal and parietal cortex of MSA brains compared with control brains. Significantly more astrocytes and microglia were observed in the frontal, parietal, and temporal cortex of MSA brains, whereas no change in the total number of oligodendrocytes was seen in any of the neocortical regions. There were significantly fewer neurons in the frontal cortex of MSA patients with impaired executive function than in patients with normal executive function. Our results indicate that the involvement of the neocortex in MSA is far more widespread and substantial than previously thought. In addition, our results suggest that the increasingly recognized cognitive impairment in MSA may be related to neuronal loss in the frontal cortex.

Autoimmune antibody decline in Parkinson’s disease and Multiple System Atrophy; a step towards immunotherapeutic strategies

BackgroundParkinson’s’ disease (PD) and Multiple System Atrophy (MSA) are progressive brain disorders characterized by intracellular accumulations of α-synuclein and nerve cell loss in specific brain areas. This loss causes problems with movement, balance and/or autonomic functions. Naturally occurring autoantibodies (NAbs) play potentially an important role in clearing or/and blocking circulating pathological proteins. Little is known about the functional properties of anti-α-synuclein NAbs in PD and MSA, and there have been opposing reports regarding their plasma concentrations in these disorders.MethodsWe have investigated the apparent affinity of anti-α-synuclein NAbs in plasma samples from 46 PD patients, 18 MSA patients and 41 controls using competitive enzyme-linked immunosorbent assay (ELISA) and Meso Scale Discovery (MSD) set-ups.ResultsWe found that the occurrence of high affinity anti-α-synuclein NAbs in plasma from PD patients is reduced compared to healthy controls, and nearly absent in plasma from MSA patients. Also, levels of α-synuclein/NAbs immunocomplexes is substantially reduced in plasma from both patient groups. Further, cross binding of anti-α-synuclein NAbs with β- and γ-synuclein monomers suggest, the high affinity anti-α-synuclein plasma component, seen in healthy individuals, is directed mainly against C-terminal epitopes. Furthermore, we also observed reduced occurrence of high affinity anti-phosphorylated-α-synuclein NAbs in plasma from PD and MSA patients.ConclusionsOne interpretation implies that these patients may have impaired ability to clear and/or block the effects of pathological α-synuclein due to insufficient/absent concentration of NAbs and as such provides a rationale for testing immune-based therapeutic strategies directed against pathological α-synuclein. Following this interpretation, we can hypothesize that high affinity autoantibodies efficiently bind and clear potentially pathological species of α-synuclein in healthy brain, and that this mechanism is impaired or absent in PD and MSA patients.

Cytokine profiling in the prefrontal cortex of Parkinson's Disease and Multiple System Atrophy patients

Parkinsons Disease (PD) and Multiple System Atrophy (MSA) are neurodegenerative diseases characterized neuropathologically by alpha-synuclein accumulation in brain cells. This accumulation is hypothesized to contribute to constitutive neuroinflammation, and to participate in the neurodegeneration. Cytokines, which are the main inflammatory signalling molecules, have been identified in blood and cerebrospinal fluid of PD patients, but studies investigating the human brain levels are scarce. It is documented that neurotrophins, necessary for survival of brain cells and known to interact with cytokines, are altered in the basal ganglia of PD patients. In regards to MSA, no major study has investigated brain cytokine or neurotrophin protein expression. Here, we measured protein levels of 18 cytokines (IL-2, 4-8, 10, 12, 13, 17, G-CSF, GM-CSF, IFN-γ, MCP-1, MIP-1α and 1β, TNF-α) and 5 neurotrophins (BDNF, GDNF, bFGF, PDGF-BB, VEGF) in the dorsomedial prefrontal cortex in brains of MSA and PD patients and control subjects. We found altered expression of IL-2, IL-13, and G-CSF, but no differences in neurotrophin levels. Further, in MSA patients we identified increased mRNA levels of GSK3β that is involved in neuroinflammatory pathways. Lastly, we identified increased expression of the neurodegenerative marker S100B, but not CRP, in PD and MSA patients, indicating local rather than systemic inflammation. Supporting this, in both diseases we observed increased MHC class II+ and CD45+ positive cells, and low numbers of infiltrating CD3+ cells. In conclusion, we identified neuroinflammatory responses in PD and MSA which seems more widespread in the brain than neurotrophic changes.

The influence of preanalytical conditions on the DJ-1 concentration in human cerebrospinal fluid

AIM The purpose of this study was to establish the influence of centrifugation and protease activity on the cerebrospinal fluid (CSF) concentrations of DJ-1 and hemoglobin. MATERIALS & METHODS The concentrations of DJ-1 and hemoglobin were determined in 12 (DJ-1) and six (hemoglobin) pairs of CSF samples, with one sample being stored without centrifugation and the other being centrifuged at 2000 × g before storage. The DJ-1 concentration was also determined in centrifuged and uncentrifuged CSF containing protease inhibitors and compared with values determined in centrifuged and uncentrifuged CSF samples without protease inhibitors. Furthermore, specific protein concentrations were determined in CSF from two groups, each comprising 23 patients with Parkinsons disease. In one group the CSF was centrifuged at 1300-1800 × g, 4°C, 10 min, and in the other at 2000 × g, 4°C, 10 min. RESULTS Centrifugation at 2000 × g resulted in significantly lower CSF DJ-1 concentrations compared with no centrifugation and centrifugation at a lower g-force. There was a significant difference in the hemoglobin concentration between centrifuged and uncentrifuged CSF. In all centrifuged samples the hemoglobin concentration was <200 ng/ml including blood contaminated samples centrifuged at 2000 × g. When a protease inhibitor cocktail was added to the CSF prior to centrifugation, the DJ-1 concentration was significantly higher. CONCLUSION Preanalytical factors such as centrifugation and protease inhibition must be carefully controlled when handling CSF for analysis of DJ-1 and other biomarkers, as DJ-1 was influenced by blood contamination, centrifugation and protease activity.