Axel Regeniter

Increased neurofilament light chain blood levels in neurodegenerative neurological diseases

Objective Neuronal damage is the morphological substrate of persisting neurological disability. Neurofilaments (Nf) are cytoskeletal proteins of neurons and their release into cerebrospinal fluid has shown encouraging results as a biomarker for neurodegeneration. This study aimed to validate the quantification of the Nf light chain (NfL) in blood samples, as a biofluid source easily accessible for longitudinal studies. Methods We developed and applied a highly sensitive electrochemiluminescence (ECL) based immunoassay for quantification of NfL in blood and CSF. Results Patients with Alzheimer’s disease (AD) (30.8 pg/ml, n=20), Guillain-Barré-syndrome (GBS) (79.4 pg/ml, n=19) or amyotrophic lateral sclerosis (ALS) (95.4 pg/ml, n=46) had higher serum NfL values than a control group of neurological patients without evidence of structural CNS damage (control patients, CP) (4.4 pg/ml, n=68, p<0.0001 for each comparison, p=0.002 for AD patients) and healthy controls (HC) (3.3 pg/ml, n=67, p<0.0001). Similar differences were seen in corresponding CSF samples. CSF and serum levels correlated in AD (r=0.48, p=0.033), GBS (r=0.79, p<0.0001) and ALS (r=0.70, p<0.0001), but not in CP (r=0.11, p=0.3739). The sensitivity and specificity of serum NfL for separating ALS from healthy controls was 91.3% and 91.0%. Conclusions We developed and validated a novel ECL based sandwich immunoassay for the NfL protein in serum (NfLUmea47:3); levels in ALS were more than 20-fold higher than in controls. Our data supports further longitudinal studies of serum NfL in neurodegenerative diseases as a potential biomarker of on-going disease progression, and as a potential surrogate to quantify effects of neuroprotective drugs in clinical trials.

Detection of subclinical tubular injury after renal transplantation: comparison of urine protein analysis with allograft histopathology.

Background. Tubulointerstitial injury due to rejection leads to tubular atrophy (TA)/interstitial fibrosis (IF) followed by deterioration of allograft function. This study investigated whether urinary tubular injury biomarkers can detect subclinical tubulitis found in protocol biopsies allowing for a noninvasive screening procedure. Methods. Four rigidly defined groups (stable transplants with normal tubular histology [n=24], stable transplants with subclinical tubulitis [n=38], patients with clinical tubulitis Ia/Ib [n=18], and patients with other clinical tubular pathologies [n=20]) were compared for differences in urinary intact/cleaved β2-microglobulin (i/cβ2m), retinol-binding protein (RBP), neutrophil-gelatinase-associated lipocalin (NGAL), and α1-microglobulin (α1m). Results. Tubular proteinuria was present in 38% (RBP) to 79% (α1m) of patients in the stable transplant with normal tubular histology group. The stable transplant with subclinical tubulitis group had slightly higher levels of i/cβ2m (P=0.11), RBP (P=0.17), α1m (P=0.09), and NGAL (P=0.06) than the stable transplant with normal tubular histology group with a substantial overlap. The clinical tubulitis Ia/Ib and the other clinical tubular pathology groups had significantly higher levels of RBP, NGAL, and α1m than stable transplants with normal tubular histology or stable transplants with subclinical tubulitis (P<0.002). Conclusions. None of the investigated biomarkers allow for clear differentiation between stable transplants with normal tubular histology and stable transplants with subclinical tubulitis. Therefore, the protocol allograft biopsy currently remains the preferred tool to screen for subclinical tubulitis. Further longitudinal studies should determine whether tubular proteinuria in stable transplants with normal tubular histology indicates a clear risk for early development of TA/IF.

Neurofilament heavy chain in CSF correlates with relapses and disability in multiple sclerosis

Objective: Neurodegeneration is now accepted as a pathologic hallmark of multiple sclerosis (MS). We sought to discover whether CSF levels of neurofilament heavy chain protein (NfHSMI35) correlate with disability, disease activity, or specific stages of MS. Methods: An electrochemiluminescence immunoassay was used to retrospectively measure NfHSMI35 in CSF of patients with clinically isolated syndrome (CIS) (n = 63), relapsing-remitting multiple sclerosis (RRMS) (n = 39), secondary progressive multiple sclerosis (SPMS) (n = 25), primary progressive multiple sclerosis (PPMS) (n = 23), or controls (n = 73). Cell count and CSF levels of immunoglobulin and albumin were also measured. Results: CSF levels of NfHSMI35 increased with age in controls (rs = 0.50, p < 0.0001) and CIS (rs = 0.50, p < 0.0001); this effect was less pronounced in RRMS (rs = 0.35, p = 0.027) and absent in SPMS/PPMS. After age correction, NfHSMI35 levels were found to be higher in all disease stages compared to control. Relapses were associated with higher CSF NfHSMI35 values compared with stable disease. NfHSMI35 levels correlated with EDSS scores in patients with CIS and RRMS (rs = 0.33, p = 0.001), and during relapse (rs = 0.35, p = 0.01); the correlation was most prominent in RRMS during relapse (rs = 0.54, p = 0.01). This was not the case for any of the other CSF markers examined. Conclusions: Neuronal loss is a feature of aging, and the age-dependent increase of CSF NfHSMI35 suggests that this loss accelerates over time. For MS, increased NfHSMI35 levels reflect the superimposed presence of further neurodegenerative processes. Evaluation of NfHSMI35 levels is likely to provide a useful surrogate for measuring the rate of neurodegeneration in MS. Furthermore, the dissociation of NfHSMI35 levels with biomarkers of inflammation suggests that the mechanisms responsible for their production are at least partly independent.

A highly sensitive electrochemiluminescence immunoassay for the neurofilament heavy chain protein

BACKGROUND The loss of neurological function is closely related to axonal damage. Neurofilament subunits are concentrated in neurons and axons and have emerged as promising biomarkers for neurodegeneration. Electrochemiluminescence (ECL) based assays are known to be of superior sensitivity and require less sample volume than conventional ELISAs. METHODS We developed an ECL based solid-phase sandwich immunoassay to measure the neurofilament heavy chain protein (NfH(SMI35)) in CSF. We employed commercially available antibodies as previously used in a conventional ELISA (Petzold et al., 2003; Petzold and Shaw, 2007). The optimised and validated assay was applied in a reference cohort and defined patient groups. RESULTS Analytical sensitivity (background plus three SD) of our assay was 2.4 pg/ml. The mean intra-assay coefficient of variation (CV) was 4.8% and the inter-assay CV 8.4%. All measured control and patient samples produced signals well above background. Patients with multiple sclerosis (MS) (median 46.2 pg/ml, n=95), amyotrophic lateral sclerosis (ALS) (160.1 pg/ml, n=50), mild cognitive impairment/Alzheimers disease (MCI/AD) (65.6 pg/ml, n=20), Guillain-Barre syndrome (GBS) (91.0 pg/ml, n=20) or subarachnoid hemorrhage (SAH) (345.0 pg/ml, n=20) had higher CSF NfH(SMI35) values than the reference cohort (27.1 pg/ml, n=73, p<0.0001 for each comparison). CONCLUSION The new ECL based assay for NfH(SMI35) in CSF is superior in terms of sensitivity, precision and accuracy to previously published methods (Petzold et al., 2003; Shaw et al., 2005; Teunissen et al., 2009). The improved performance and small sample volume requirement qualify this method in experimental settings and clinical trials designed to perform a number of tests on limited amounts of material.

Antimyelin antibodies in clinically isolated syndromes correlate with inflammation in MRI and CSF

ObjectiveWe investigated the correlation of anti-myelin oligodendrocyte glycoprotein- (anti-MOG) and anti-myelin basic protein antibodies (anti-MBP) in serum of CIS patients with inflammatory signs in MRI and in CSF and, as previously suggested, the incidence of more frequent and rapid progression to clinically definite MS (CDMS).Methods133 CIS patients were analysed for anti-MOG and anti-MBP (Western blot). Routine CSF and cranial MRI (quantitatively and qualitatively) measures were analyzed. 55 patients had a follow-up of at least 12 months or until conversion to CDMS.ResultsPatients with anti-MOG and anti-MBP had an increased intrathecal IgG production and CSF white blood cell count (p = 0.048 and p = 0.036). When anti-MBP alone, or both antibodies were present the cranial MRI showed significantly more T2 lesions (p = 0.007 and p = 0.01, respectively). There was a trend for more lesion dissemination in anti-MBP positive patients (p = 0.076). Conversely, anti-MOG- and/or anti-MBP failed to predict conversion to CDMS in our follow-up group (n = 55). Only in female patients with at least one MRI lesion (n = 34) did the presence of anti-MOG correlate with more frequent (p = 0.028) and more rapid (p = 0.0209) transition to CDMS.ConclusionsPresence of anti-MOG or anti-MBP or both was not significantly associated with conversion to CDMS in our CIS cohort. However, patients with anti-MOG and anti-MBP had higher lesion load and more disseminated lesions in cranial MRI as well as higher values for CSF leucocytes and intrathecal IgG production. Our data support a correlation of anti-MOG and anti-MBP to inflammatory signs in MRI and CSF. The prognostic value of these antibodies for CDMS, however, seems to be less pronounced than previously reported.

Tubular Toxicity in Sirolimus- and Cyclosporine-Based Transplant Immunosuppression Strategies: An Ancillary Study From a Randomized Controlled Trial

BACKGROUND Sirolimus has been promoted as an agent to provide immunosuppression for kidney transplant recipients that, in contrast to calcineurin inhibitors, would not be nephrotoxic. However, several reports have observed proteinuria in patients treated with sirolimus, ranging from low grade to nephrotic range. Accordingly, we compared markers of tubular and glomerular damage in an ancillary study of a randomized trial comparing sirolimus and cyclosporine. STUDY DESIGN Single-center, open-label, randomized, prospective trial. SETTING & PARTICIPANTS Patients undergoing cadaveric or living donor kidney transplant at the University Hospital in Basel, Switzerland, between January 2001 and July 2004. INTERVENTION Immunosuppression regimen consisting of cyclosporine, mycophenolate mofetil, and prednisone versus sirolimus, mycophenolate mofetil, and prednisone. OUTCOMES The primary outcome was kidney function, assessed using serum creatinine level. Secondary outcomes included patient and graft survival, number of rejections, and evidence of kidney damage, assessed using glomerular and tubular urine biomarker levels. MEASUREMENTS Urine and serum were collected at 0, 7, 30, and 90 days. Kidney function was estimated using serum creatinine level. Urinary markers included alpha(1)-microglobulin and retinol-binding protein (tubular), transferrin and albumin (glomerular), and semiquantitative assessment of glucosuria. Protocol kidney biopsies were performed at days 90 and 180. RESULTS There were 63 patients randomly assigned to cyclosporine-based regimens, and 64, to sirolimus-based regimens. Kidney function was similar in both groups, whereas levels of markers associated with glomerular damage (albumin, 19.5 vs 8.96 mg/mmol creatinine; P < 0.001; transferrin, 13.1 vs 5.7 mg/mmol creatinine; P < 0.001) and those associated with tubular damage (alpha(1)-microglobulin, 11 vs 7.6 mg/mmol creatinine; P = 0.004; retinol-binding protein, 19.6 vs 9.6 mg/mmol creatinine; P = 0.002) were higher beginning at day 7 in patients randomly assigned to sirolimus therapy, with similar findings through day 90. Glucosuria incidence was higher in patients randomly assigned to sirolimus therapy beginning by day 30 (65% vs 30% on day 30; P = 0.002; 51% vs 22% on day 90; P < 0.001). On histologic examination, the overall severity of tubular lesions was significantly higher in patients randomly assigned to sirolimus therapy. LIMITATIONS Small sample size, short-term follow-up likely insufficient to appreciate calcineurin-associated nephropathy. CONCLUSION Compared with a cyclosporine-based immunosuppression regimen, a sirolimus-based regimen is associated with de novo low-grade glomerular proteinuria, increased excretion of markers associated with tubular damage, and evidence of tubular damage on kidney biopsy.

CSF-Tau and CSF-Aβ1–42 in Posterior Cortical Atrophy

Objective: Our purpose was to measure Aβ1–42, T-tau and P-tau181 in the cerebrospinal fluid (CSF) of patients with posterior cortical atrophy (PCA), a presenile dementia likely to represent a variant of Alzheimer’s disease (AD). Methods: CSF samples from 34 subjects including 9 patients with PCA, 11 age-matched patients with AD and 14 age-matched cognitively healthy controls were analyzed using commercially available ELISA kits. Results: The Aβ1–42, T-tau and P-tau181 levels in PCA patients differed significantly (p < 0.02) from those in healthy controls but were indistinguishable from subjects with a clinical diagnosis of AD. Conclusion: High T-tau and P-tau181 and low Aβ1–42 levels in PCA – typically observed in AD – indicate that the underlying pathology of PCA is usually AD. If these findings are replicated in PCA patients with autopsy-confirmed AD neuropathology, PCA patients may be eligible for disease-modifying AD treatments.

A modern approach to CSF analysis: pathophysiology, clinical application, proof of concept and laboratory reporting.

The CNS immune response often leads to characteristic interrelated biochemical changes in cerebrospinal fluid. Multiple analytes, i.e. cell count, cell differential, evaluation of barrier function and intrathecal IgG, IgA and IgM synthesis should be included in basic diagnostic workup. We describe the scientific background, laboratory investigations and characteristic patterns found with basic CSF analysis, based on the recommendations of the German cerebrospinal fluid society. The concept is substantiated by retrospectively analyzing data of 4026 paired CSF/serum samples. 53% of our samples presented with at least one or several combined abnormal findings. An intrathecal IgG, IgA or IgM immunoglobulin response (37%, n=1481) and a blood-CSF barrier dysfunction (37%; n=1473) were most frequent; followed by an elevated leukocyte cell count (25%; n=992). The immunoglobulin response showed an intrathecal production of IgG in 49% (n=731/1481), which was only detectable in isoelectric focusing in 27% (n=200/731). Intrathecal IgM (n=389) and IgA (n=361) synthesis presented with nearly equal frequency of 25% in samples with intrathecal immunoglobulin response. The immunoglobulin pattern showed a solitary one class reaction of IgG, IgA or IgM in 67%, a combined two class reaction of IgG/IgA, IgG/IgM or IgA/IgM synthesis in 16% and a combined three-class reaction of IgG, IgA and IgM in 17%. This approach generates valuable but numerous complex and interrelated biochemical data. We therefore developed a knowledge-based system combined with visual oriented laboratory output to transfer the information more effectively. This often uncovers typical patterns specific for distinct neurological diseases, is well accepted by our medical community documented by a 37% increase in external ordering.

Safety and tolerability of sirolimus treatment in patients with autosomal dominant polycystic kidney disease

BACKGROUND We initiated a randomized controlled clinical trial to assess the effect of sirolimus on disease progression in patients affected by autosomal dominant polycystic kidney disease (ADPKD). Here we report the preliminary safety results of the first 6 months of treatment. METHOD A total of 25 patients were randomized to sirolimus 2 mg/day and 25 patients to no treatment except standard care. Treatment adherence was monitored electronically. At baseline and at Month 6, laboratory parameters were analysed and the urinary protein profile in 24-h urine collections was determined. RESULTS Both treatment groups were well balanced for age, sex and renal function. In 94.1 +/- 11.4% of the study days, patients in the sirolimus group were exposed to the drug when assuming a therapeutic efficacy duration of 30 h. At Month 6, the mean sirolimus dose and trough level were 1.28 +/- 0.71 mg/day and 3.8 +/- 1.9 microg/l, respectively. Glomerular (albumin, transferrin, IgG) and tubular (retinol-binding protein, alpha(1)-microglobulin) protein excretion remained unchanged. Glomerular filtration rate also did not change significantly. Haematological parameters were similar in both groups, except for a mild reduction of the mean corpuscular volume of erythrocytes in patients receiving sirolimus. Lipid levels were similar in both groups. Adverse events were transient and mild, and no grade 3 or 4 events occurred. The incidence of infections was similar in the sirolimus group (80%) and the standard group (88%). The most common gastrointestinal adverse events were mucositis (72% in the sirolimus group versus 16% in the standard group, P = 0.0001) and diarrhoea (36% in the sirolimus versus 20% in the standard group, P = 0.345). CONCLUSION Treatment of ADPKD patients with sirolimus with a dose of 1-2 mg/day is safe and does not cause proteinuria or impairment of GFR. Treatment adherence was excellent. (ClinicalTrials.gov number, NCT00346918.).

Windows to the Ward: Graphically Oriented Report Forms. Presentation of Complex, Interrelated Laboratory Data for Electrophoresis/Immunofixation, Cerebrospinal Fluid, and Urinary Protein Profiles

BACKGROUND Automated laboratory analyzers that mass produce data have been linked to information systems for more than two decades, but little progress has been made in developing more comprehensible report forms. Results are still reported in computer-generated printouts containing hundreds of numbers crowded into columns on each printed page. METHODS We developed three software applications focusing on the graphic presentation of laboratory results. RESULTS The first application summarizes data for a patient with a monoclonal gammopathy. The report provides a cumulative graphic presentation of immunofixation/electrophoresis data without any additional interpretation, focuses on a color-coded electrophoresis scan, and records up to 5 years on a single page. The second application deals with cerebrospinal fluid analysis. The report calculates relevant data and graphs the complex relationship between albumin and immunoglobulin results from paired serum and cerebrospinal fluid samples. Manually added interpretive text assures an output comprehensible to clinicians in all specialties. The third application produces a report summarizing quantitatively measured urinary marker protein profiles. The report form is generated by a flexible, completely user-definable knowledge-based system. It calculates numerous ratios and formulae, supports reflex testing, supplies an automated interpretation, and generates a specific graphic signature pattern of the results (MDI LabLink proteinuria differentiation). CONCLUSIONS Increased clinical demand for graphically oriented report forms 5 years after their introduction has provided evidence that these reports transfer complex laboratory data and results to the clinician more effectively. The highest (more than threefold) increase in demand has been for reports for urinary marker protein profiles that feature a largely self-explanatory graphic signature pattern.