BAMBI and CHGA in Prion Diseases: Neuropathological Assessment and Potential Role as Disease Biomarkers.

Prion diseases affect both animals and humans. Research in the natural animal model of the disease could help in the understanding of neuropathological mechanisms and in the development of biomarkers for human pathologies. For this purpose, we studied the expression of 10 genes involved in prion propagation in vitro in the central nervous system of scrapie-infected sheep. Dysregulated genes (BAMBI and CHGA) were further analysed in a transgenic murine model (Tg338) of scrapie, and their protein distribution was determined using immunohistochemistry and Western blot. Their potential as biomarkers was finally assessed using enzyme-linked immunosorbent assay (ELISA) in cerebrospinal fluid (CSF) of scrapie sheep and Creutzfeldt-Jakob disease (CJD) patients. Protein BAMBI was upregulated in highly affected brain areas and CHGA was overexpressed along the brain in both models. Moreover, BAMBI and CHGA immunostaining scores strongly correlated with spongiosis and microgliosis in mice. Finally, levels of BAMBI were significantly higher in the CSF of clinical sheep and CJD patients. In addition to their potential as biomarkers, our work confirms the role of BAMBI and CHGA in prion neuropathology in vivo, but besides prion replication, they seem to be involved in the characteristic neuroinflammatory response associated to prion infection.

Chromogranin A Analysis in the Differential Diagnosis Across Lewy Body Disorders.

BACKGROUND: Chromogranin A (CgA) is a general marker of gut endocrine cells, which are part of the "gut-brain axis" in Parkinson's disease (PD). OBJECTIVE: We analyzed CgA as a marker of synaptic dysfunction to assess its role in the differential diagnosis across different Lewy body disorders. METHODS: We analyzed the CgA levels in the cerebrospinal fluid (CSF) and serum from 54 patients covering the spectrum of Lewy body disorders [13 Parkinson's disease (PD), 17 Parkinson's disease dementia (PDD), 24 dementia with Lewy bodies (DLB)] and 14 controls using an ELISA. RESULTS: A positive correlation was noted between CSF and serum CgA levels (ρ= 0.47, 95% CI: 0.24 to 0.65, p < 0.0001). The highest values of CgA in CSF and in serum were measured in DLB and there was a significant difference between DLB and PDD (p = 0.03 and p = 0.004). The serum levels of CgA in controls achieved lower values compared to DLB (p = 0.006). There was a gradual increase in serum levels from PD to PDD and DLB. An inverse correlation was seen between the CSF level of CgA and Aß42 (ρ  = -0.296, 95% CI: -0.51 to -0.04, p = 0.02). CONCLUSION: The incorporation of CgA analysis as an additional biomarker may be useful in the diagnostic work-up of Lewy body dementia. CgA analysis may be relevant in distinguishing DLB from PDD patients and presumably early stages of PD. Our data on altered serum levels in DLB pave the way to the development of blood-based parameters for the differential diagnosis, which however needs to be confirmed in a prospective study.

Chromogranin A levels in the cerebrospinal fluid of patients with amyotrophic lateral sclerosis.

Chromogranin A (CgA) is a protein found in large dense-core vesicles of neuroendocrine cells and neurons and regulating secretion. A relevance to amyotrophic lateral sclerosis (ALS) was suggested as its overexpression accelerates disease onset in model systems and it interacts with mutant forms of SOD1. Recently, increased cerebrospinal fluid (CSF) CgA levels have been reported in ALS patients relative to controls. With the aim of confirming this finding, we measured CgA and phosphorylated neurofilament heavy chain (pNFH), an established ALS biomarker, in the CSF of 32 ALS patients and 32 disease controls. ALS patients had clearly increased pNFH levels (p < 0.0001), while CgA levels were only modestly lower relative to controls (p = 0.0265), with wide value overlap and consequently poor discriminative performance. CgA did not correlate with any disease parameters among ALS patients. Our findings suggest that CgA is not a promising clinical biomarker for ALS.

A Parallel Reaction Monitoring Mass Spectrometric Method for Analysis of Potential CSF Biomarkers for Alzheimer's Disease.

SCOPE: The aim of this study was to develop and evaluate a parallel reaction monitoring mass spectrometry (PRM-MS) assay consisting of a panel of potential protein biomarkers in cerebrospinal fluid (CSF). EXPERIMENTAL DESIGN: Thirteen proteins were selected based on their association with neurodegenerative diseases and involvement in synaptic function, secretory vesicle function, or innate immune system. CSF samples were digested and two to three peptides per protein were quantified using stable isotope-labeled peptide standards. RESULTS: Coefficients of variation were generally below 15%. Clinical evaluation was performed on a cohort of 10 patients with Alzheimer's disease (AD) and 15 healthy subjects. Investigated proteins of the granin family exhibited the largest difference between the patient groups. Secretogranin-2 (p<0.005) and neurosecretory protein VGF (p<0.001) concentrations were lowered in AD. For chromogranin A, two of three peptides had significantly lowered AD concentrations (p<0.01). The concentrations of the synaptic proteins neurexin-1 and neuronal pentraxin-1, as well as neurofascin were also significantly lowered in AD (p<0.05). The other investigated proteins, ß2-microglobulin, cystatin C, amyloid precursor protein, lysozyme C, neurexin-2, neurexin-3, and neurocan core protein, were not significantly altered. CONCLUSION AND CLINICAL RELEVANCE: PRM-MS of protein panels is a valuable tool to evaluate biomarker candidates for neurodegenerative disorders.

Cerebrospinal fluid levels of chromogranin A and phosphorylated neurofilament heavy chain are elevated in amyotrophic lateral sclerosis.

BACKGROUND: Various cerebrospinal fluid (CSF) biomarkers are being studied to improve the sensitivity and specificity of the diagnostic methods for amyotrophic lateral sclerosis (ALS). AIMS OF THE STUDY: The aim of our study was to establish the CSF levels of chromogranin A (CgA) and phosphorylated neurofilament heavy chain (pNF-H) in patients with ALS in order to assess these proteins as possible biomarkers of ALS. METHODS: Cerebrospinal fluid levels of CgA and pNF-H were examined and mutually compared in 15 patients with sporadic ALS and 16 gender- and age-matched controls. RESULTS: Lumbar CSF CgA levels were increased in the patients with ALS compared to the controls (median 235 vs 138, P=.031). Lumbar CSF pNF-H levels were significantly increased in the patients with ALS compared to the control group (median 3091 vs 213, P<.0001). CONCLUSIONS: Identifying CSF biomarkers in ALS is important in order to establish the diagnosis in the early stages of the disease. pNF-H seems to be a good biomarker for the diagnosis of ALS. If confirmed on a larger group of patients, CgA may also become useful in the diagnosis of sporadic ALS.

Elevated Expression of the Cerebrospinal Fluid Disease Markers Chromogranin A and Clusterin in Astrocytes of Multiple Sclerosis White Matter Lesions.

Using proteomics, we previously identified chromogranin A (CgA) and clusterin (CLU) as disease-related proteins in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS). CgA and CLU are involved in cell survival and are implicated in neurodegenerative disorders and may also have roles in MS pathophysiology. We investigated CgA and CLU expression in lesions and nonlesional regions in postmortem brains of MS patients and controls and in the brains of marmosets with experimental autoimmune encephalomyelitis. By quantitative PCR, mRNA levels of CgA and CLU were elevated in white matter but not in grey matter of MS patients. In situ analyses showed greater expression of CgA and CLU in white matter lesions than in normal-appearing regions in MS patients and in the marmosets, primarily in or adjacent to perivascular spaces and inflammatory infiltrates. Both proteins were expressed by glial fibrillary acidic protein-positive astrocytes. CgA was more localized in astrocytic processes and endfeet surrounding blood vessels and was abundant in the superficial glia limitans and ependyma, 2 CSF-brain borders. Increased expression of CgA and CLU in reactive astrocytes in MS white matter lesions supports a role for these molecules as neuro-inflammatory mediators and their potential as CSF markers of active pathological processes in MS patients.

Orthostatic hypotension is associated with decreased cerebrospinal fluid levels of chromogranin A in early stage of Parkinson disease.

An association between the CSF chromogranin A (CgA) and orthostatic blood pressure changes was investigated in 20 patients in the early stage of Parkinson disease (PD). There was a positive correlation between the CSF CgA and diastolic blood pressure change, when CSF CgA levels were lower in patients with orthostatic hypotension (OH). Decreased CSF CgA may be useful in predicting OH in the early stage of PD.

CSF protein biomarkers predicting longitudinal reduction of CSF ß-amyloid42 in cognitively healthy elders.

ß-amyloid (Aß) plaque accumulation is a hallmark of Alzheimer's disease (AD). It is believed to start many years prior to symptoms and is reflected by reduced cerebrospinal fluid (CSF) levels of the peptide Aß1-42 (Aß42). Here we tested the hypothesis that baseline levels of CSF proteins involved in microglia activity, synaptic function and Aß metabolism predict the development of Aß plaques, assessed by longitudinal CSF Aß42 decrease in cognitively healthy people. Forty-six healthy people with three to four serial CSF samples were included (mean follow-up 3 years, range 2-4 years). There was an overall reduction in Aß42 from a mean concentration of 211-195 pg ml(-1) after 4 years. Linear mixed-effects models using longitudinal Aß42 as the response variable, and baseline proteins as explanatory variables (n=69 proteins potentially relevant for Aß metabolism, microglia or synaptic/neuronal function), identified 10 proteins with significant effects on longitudinal Aß42. The most significant proteins were angiotensin-converting enzyme (ACE, P=0.009), Chromogranin A (CgA, P=0.009) and Axl receptor tyrosine kinase (AXL, P=0.009). Receiver-operating characteristic analysis identified 11 proteins with significant effects on longitudinal Aß42 (largely overlapping with the proteins identified by linear mixed-effects models). Several proteins (including ACE, CgA and AXL) were associated with Aß42 reduction only in subjects with normal baseline Aß42, and not in subjects with reduced baseline Aß42. We conclude that baseline CSF proteins related to Aß metabolism, microglia activity or synapses predict longitudinal Aß42 reduction in cognitively healthy elders. The finding that some proteins only predict Aß42 reduction in subjects with normal baseline Aß42 suggest that they predict future development of the brain Aß pathology at the earliest stages of AD, prior to widespread development of Aß plaques.

Cerebrospinal fluid levels of chromogranin A in the treatment-naïve early stage Parkinson's disease: a pilot study.

Chromogranin A (CgA) levels in cerebrospinal fluid (CSF) have been reported to be significantly reduced in the later stages of Parkinson's disease (PD). There are only limited data regarding its levels in the early stages, so its significance as a potential biomarker in the diagnosis of PD cannot be established. The aim of our study was to establish the level of CgA in a cohort of treatment-naïve patients with early stage PD. Ten patients (4 males, 6 females) and 10 gender- and age-matched controls were examined for CgA levels in the CSF. Control subjects were patients with low-back pain or tension-type headache. The mean CSF CgA level in PD patients was 74.8 (41.9-123.8) µg/l; in the control group it was 143.9 (116-181.3) µg/l. Statistical analysis showed a difference at the significance level P ≤ 0.05. Our pilot study shows that CSF CgA levels are reduced in the early stages of PD. CgA could therefore be a potential biomarker helpful in the diagnosis of PD.

Hyperthermia and postmortem biochemical investigations.

The postmortem diagnosis of heat-related deaths presents certain difficulties. Firstly, preterminal or terminal body temperatures are often not available. Additionally, macroscopic and microscopic findings are nonspecific or inconclusive and depend on survival duration after exposure. The diagnosis of hyperthermia is therefore essentially based on scene investigation, the circumstances of death, and the reasonable exclusion of other causes of death. Immunohistochemistry and postmortem biochemical investigations have been performed by several authors in order to better circumstantiate the physiopathology of hyperthermia and provide further information to confirm or exclude a heat-related cause of death. Biochemical markers, such as electrolytes, hormones, blood proteins, enzymes, and neurotransmitters, have been analyzed in blood and other biological fluids to improve the diagnostic potential of autopsy, histology, and immunohistochemistry. The aim of this article is to present a review of the medicolegal literature pertaining to the postmortem biochemical investigations that are associated with heat-related deaths.

Longitudinal cerebrospinal fluid biomarkers over four years in mild cognitive impairment.

Cerebrospinal fluid (CSF) measurements of amyloid-ß42 (Aß42), total-tau (T-tau), and phosphorylated tau (P-tau) may be used to predict future Alzheimer's disease (AD) dementia in patients with mild cognitive impairment (MCI). The precise temporal development of these biomarkers in relation to clinical progression is unclear. Earlier studies have been hampered by short follow-up. In an MCI cohort, we selected 15 patients who developed AD (MCI-AD) and 15 who remained cognitively stable during 4 years of follow-up. CSF was sampled at three serial occasions from each patient and analyzed for Aß peptides, the soluble amyloid-ß protein precursor protein fragments sAßPPα and sAßPPß, T-tau, P-tau, and chromogranin B, which is a protein linked to regulated neuronal secretion. We also measured, for the first time in MCI patients, an extended panel of Aß peptides by matrix-assisted-laser-desorption/ionization time-of-flight mass spectrometry (MS). Most biomarkers were surprisingly stable over the four years with coefficients of variation below or close to 10%. However, MCI-AD patients decreased in CSF AßX₋40 and chromogranin B concentrations, which may indicate a reduced number of functional neurons or synapses with disease progression. The MS Aß peptide panel was more useful than any single Aß peptide to identify MCI-AD patients already at baseline. Knowledge on these biomarkers and their trajectories may facilitate early diagnosis of AD and be useful in future clinical trials to track effects of disease modifying drugs.

A novel panel of cerebrospinal fluid biomarkers for the differential diagnosis of Alzheimer's disease versus normal aging and frontotemporal dementia.

BACKGROUND: An early and accurate diagnosis of Alzheimer's disease (AD) is important in order to initiate symptomatic treatment with currently approved drugs and will be of even greater importance with the advent of disease-modifying compounds. METHODS: Protein profiles of human cerebrospinal fluid samples from patients with AD (n = 85), frontotemporal dementia (n = 20), and healthy controls (n = 32) were analyzed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry to verify previously discovered biomarkers. RESULTS: We verified 15 protein biomarkers that were able to differentiate between AD and controls, and 7 of these 15 markers also differentiated AD from FTD. CONCLUSION: A panel of cerebrospinal fluid protein markers was verified by a proteomics technology which may potentially improve the accuracy of the AD diagnosis.