- Email: [email protected]
Serum neurofilament light chain in progressive supranuclear palsy
Accepted Manuscript Serum neurofilament light chain in progressive supranuclear palsy Laura Donker Kaat, Lieke H. Meeter, Wan Zheng Chiu, Shami Melhem BsC, Agnita J.W. Boon, Kaj Blennow, Henrik Zetterberg, John C. van Swieten PII:
S1353-8020(18)30277-3
DOI:
10.1016/j.parkreldis.2018.06.018
Reference:
PRD 3704
To appear in:
Parkinsonism and Related Disorders
Received Date: 10 April 2018 Revised Date:
8 June 2018
Accepted Date: 11 June 2018
Please cite this article as: Kaat LD, Meeter LH, Chiu WZ, BsC SM, Boon AJW, Blennow K, Zetterberg H, van Swieten JC, Serum neurofilament light chain in progressive supranuclear palsy, Parkinsonism and Related Disorders (2018), doi: 10.1016/j.parkreldis.2018.06.018. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
1
Serum neurofilament light chain in progressive supranuclear palsy
2 4 5
Laura Donker Kaat MD, PhD1,2, Lieke H. Meeter MD1, Wan Zheng Chiu MD1, Shami Melhem BsC1, Agnita J.W. Boon MD, PhD1, Kaj Blennow MD, PhD3,4, Henrik Zetterberg MD, PhD3,4,5,6 and John C. van Swieten MD, PhD1,7
RI PT
3
6 7
1
8
2
11 12 13 14 15 16
SC
10
M AN U
9
Department of Neurology, Erasmus Medical Center Rotterdam, the Netherlands Department of Clinical Genetics, Leiden University Medical Center, the Netherlands 3 Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospital, Mölndal, Sweden 4 Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden 5 Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, United Kingdom 6 UK Dementia Research Institute at UCL, London, United Kingdom 7 Department of Clinical Genetics, VU Medical Center Amsterdam, the Netherlands
17 18 19
Corresponding author:
20
TE D
21 22 23 24
EP
25
Word count:
27
Key words:
28
Funding sources for study:
AC C
26
29 30 31
Laura Donker Kaat Erasmus MC, Department of Neurology, Ee2293 Postbus 2040, 3000 CA Rotterdam The Netherlands +31-(0)10-7043828 email: [email protected] 1563
neurofilament, biomarker, progressive supranuclear palsy
Prinses Beatrix Fonds
1
ACCEPTED MANUSCRIPT
ABSTRACT
33
Introduction Neurofilament light chain (NfL) is a promising biomarker in neurodegenerative
34
diseases. Elevated NfL levels in CSF and blood have been observed in a growing number of
35
neurodegenerative disorders, including frontotemporal dementia and Alzheimer’s disease. We
36
studied serum NfL levels in patients with progressive supranuclear palsy (PSP) in relation to disease
37
severity and survival.
38
Methods Serum NfL levels were determined cross-sectionally in a retrospective cohort of 131
39
patients with PSP and 95 healthy controls. Detailed clinical examination was performed and disease
40
severity was assessed by several rating scales.
41
Results We found that serum NfL levels in PSP were twice as high as those in controls, and that NfL
42
levels correlated with worse functional, motor and cognitive functioning. During follow-up, 119 PSP
43
patients had died, and higher NfL levels were associated with a shorter survival.
44
Conclusion This study provides evidence that serum NfL is a relevant and promising biomarker in
45
PSP for disease severity, and may be used as a prognostic tool to predict survival in clinical practice.
SC
M AN U
TE D
EP AC C
46
RI PT
32
2
ACCEPTED MANUSCRIPT
INTRODUCTION
48
There is an urgent need for sensitive, easily accessible biomarkers in neurodegenerative disorders
49
to monitor both disease progression and the effects of treatment. Elevated levels of neurofilament
50
light chain (NfL), a neuronal cytoskeletal protein, reflect neuronal injury and have been found in the
51
cerebral spinal fluid (CSF) of patients with several neurodegenerative disorders.[1] An important
52
recent finding is that NfL levels can be reliably measured in blood, and that these correlate well
53
with NfL levels in CSF.[2]. In familial AD [3], but not in familial FTD [4], serum concentrations of NfL
54
are already increased prior to symptom onset, indicating an early disease marker in certain
55
neurodegenerative disorders.
56
Progressive supranuclear palsy (PSP) is a neurodegenerative disorder characterized by
57
parkinsonism, frequent falls, supranuclear gaze palsy and widespread tau positive inclusions at
58
brain autopsy. Elevated NfL levels have been found in PSP patients’ CSF.[5-8] Blood NfL has recently
59
been shown to be a useful biomarker for assessing disease severity and predicting disease
60
progression in PSP patients.[9] In addition, blood NfL has a good diagnostic performance in the
61
discrimination of atypical parkinsonism (including PSP) from Parkinson’s disease.[10] Elevated NfL is
62
however not specific to PSP as increased levels have also been found in several other
63
neurodegenerative diseases. NfL levels have been associated with survival in frontotemporal
64
dementia (FTD), Alzheimer’s disease (AD) and amyotrophic lateral sclerosis (ALS).[4, 11, 12] This
65
prognostic value has not been studied in PSP, except for a small study of 12 patients where
66
mortality at 24-month follow up was associated with high CSF NfL levels.[5]
AC C
EP
TE D
M AN U
SC
RI PT
47
3
ACCEPTED MANUSCRIPT
In this retrospective case-control study, we investigated serum NfL levels in a large and well
68
characterized cohort of PSP patients, demonstrating its relationship with disease severity and
69
survival.
70
METHODS
71
Subjects
72
PSP patients were enrolled between 2003 and 2014 as part of a Dutch genetic epidemiological PSP
73
study.[13] The study was approved by the Medical Ethical committee of Erasmus MC; all
74
participants or legal representatives signed informed consent. Inclusion in the study took place at
75
the out-patients clinic, or by visiting patients at home or in nursing homes. At study entry, detailed
76
clinical assessment was performed, including an interview with the care-giver and an extensive
77
neurological examination with the assessment of the following rating scales: PSP-rating scale (PSP-
78
RS), Mini Mental State Examination (MMSE), Frontal Assessment Battery (FAB), Hoehn and Yahr
79
(HY) scale and Schwab and England Activities of Daily Living (SEADL). In a consensus meeting,
80
clinical data were reviewed, and the diagnosis PSP was established according to the National
81
Institute for Neurological Disorders and Society for PSP (NINDS-SPSP) criteria. Controls were healthy
82
spouses or caregivers from stroke patients, above 55 years of age and randomly selected from a
83
large database.
SC
M AN U
TE D
EP
AC C
84
RI PT
67
85
NfL measurement
86
Blood sampling from PSP patients was carried out at the time of study entry when clinical
87
assessment was performed. Serum samples from PSP patients and controls were centrifuged the
88
same day and stored at -80°C in aliquots. For the analysis, we used one aliquot, that underwent
4
ACCEPTED MANUSCRIPT
only one thaw/freeze cycle. We used a recently developed, ultrasensitive Simoa assay to measure
90
the sample NfL levels.[2] The measurements were performed in one round of experiments using
91
one batch of reagents by board-certified technicians who were blinded to clinical data. For a quality
92
control sample with a concentration of 16.8 pg/ml, repeatability was 7.36% and intermediate
93
precision was 7.43%. For a quality control sample with a concentration of 127 pg/ml, repeatability
94
was 6.69% and intermediate precision was 8.24%.
SC
RI PT
89
95
Statistical analysis
97
Differences in demographics between cases and controls were analyzed using parametric and non-
98
parametric statistics as appropriate (SPSS version 21.0).
99
Six subjects (2 controls and 4 cases) with extremely high NfL values (>2 SD above the mean) were
100
considered as outliers and their NfL values were replaced by values corresponding to the upper 2
101
SD cut off. Because of non-normality, log transformation of NfL data was performed. Age was
102
correlated with NfL levels in both cases (Spearman’s rho=0.37, p<0.001) and controls (Spearman’s
103
rho=0.55, p<0.001). We conducted therefor an ANCOVA to analyze NfL levels between cases and
104
controls adjusted for age. The diagnostic accuracy of NfL was examined using receiver operating
105
characteristic (ROC) curve analysis, with optimal cut off according to Youden’s index. Correlations
106
between NfL and disease severity (measured by PSP-RS, MMSE, FAB, SEADL and HY scale) were
107
studied using linear regression analyses, with age and gender as covariates.
108
During follow up, 119 PSP patients had died and survival time was calculated from the moment of
109
serum collection till date of death. In twelve patients the deceased status was unknown and in
110
these subjects survival time was calculated from the moment of serum collection till last contact
AC C
EP
TE D
M AN U
96
5
ACCEPTED MANUSCRIPT
111
alive and entered as censored data. Survival in PSP patients was compared between NfL tertiles by
112
Kaplan-Meier curves with log-rank tests and Cox regressions adjusted for age and gender.
AC C
EP
TE D
M AN U
SC
RI PT
113
6
ACCEPTED MANUSCRIPT
RESULTS
115
Serum NfL levels were determined in 131 PSP patients and 95 controls. PSP patients showed
116
significantly higher NfL levels compared to controls (Table 1 and Figure 1A). This significance held
117
after correction for age and sex on log-transformed NfL (p<0.001). We were able to accurately
118
distinguish PSP patients from controls using serum NfL (area under the curve 0.87, 95% confidence
119
interval 0.83-0.92). A cutoff value of 38.3 pg/ml provided a sensitivity of 90% and specificity of 63%.
120
During follow-up, 23 patients underwent brain autopsy and in all cases the diagnosis PSP was
121
confirmed (filled black circles in figure 1A).
SC
M AN U
122
RI PT
114
Significant correlations were found between NfL levels and PSP-RS sum scores (β= 0.37, p<0.001), SEADL scores (β= -0.32, p=0.001), HY scale (β=0.30, p=0.001), FAB scores (β= -0.29,
124
p=0.004) and MMSE scores (β= -0.18, p=0.05), indicating that higher NfL levels are associated with
125
more severe motor, functional and cognitive disability. No associations were found between NfL
126
levels and age at symptom onset or disease duration from onset till serum collection.
127
TE D
123
PSP-patients with higher NfL levels showed worse survival (Log Rank test p<0.001, Figure 1B). After adjusting for age and sex, NfL levels remained significantly associated with worse survival
129
(Hazard Ratio 1.5 [1.1-1.9], p=0.003).
131
AC C
130
EP
128
7
ACCEPTED MANUSCRIPT
DISCUSSION
133
This cross-sectional study shows that serum NfL levels are elevated in PSP patients, and that these
134
are associated with disease severity and survival. Serum NfL is thus a promising biomarker in PSP
135
with the major advantages over CSF that sample collection is minimally invasive and can be easily
136
repeated over time. Because of the association with disease severity and survival, serum NfL may
137
serve as a prognostic tool in clinical practice. Additionally, it can facilitate study design for
138
therapeutic trials and genetic studies to categorize patients into disease subtypes.
139
The NfL concentrations in PSP patients were twice as high as those in controls, which is similar the
140
results from two previous studies on blood-based NfL in PSP.[9, 10] We further demonstrate that
141
NfL levels correlate with motor, cognitive and functional disability in PSP, at least at a cross
142
sectional level in this study. Comparably, a previous study showed that blood NfL levels were
143
correlated with Hoehn and Yahr stage and UPDRS-III motor scores,[10] while in another study, high
144
baseline NfL levels were associated with a more rapid neurological, functional and
145
neuropsychological decline.[9] In addition to this, we show that high serum NfL levels are
146
associated with shorter survival. This prognostic value, has been demonstrated for NfL in a few
147
other neurodegenerative diseases, but usually measured in CSF[4, 11, 12], whereas in blood, this
148
association has only been demonstrated in ALS and FTD patients so far.[4, 14, 15]
149
Absolute NfL concentrations differed between our cohort and previous studies, which has been
150
observed before.[10] There are many factors which may explain this difference such as age, disease
151
severity, sampling or storage effects, inter-laboratory variation and the application of serum versus
152
plasma. Before the implementation of NfL in clinical practice, standardized procedures with uniform
153
protocols across sites and the establishment of cut-off levels are necessary.
AC C
EP
TE D
M AN U
SC
RI PT
132
8
ACCEPTED MANUSCRIPT
In 23 individuals (18%), the diagnosis PSP was confirmed at autopsy and these patients showed mild
155
to strongly increased NfL levels, not different from clinically diagnosed PSP patients (Figure 1A). A
156
few PSP patients showed extremely high NfL levels. It is possible that other comorbidities (such as a
157
minor stroke or head trauma) may have influenced NfL levels at that time in these patients. The
158
presence of high NfL values in a few control subjects remains unresolved, as we have no additional
159
clinical information or neuroimaging data.
SC
RI PT
154
The strengths of the current study are the large sample size with substantial pathological
160
confirmation, a clinically well characterized cohort with the assessment of several rating scales, and
162
the long period of follow-up, including information on survival. We also acknowledge some
163
limitations. First, this study relies on cross-sectional acquired data, with many patients at an
164
advanced disease stage. Longitudinal data would have been valuable in helping to determine
165
whether and how NfL concentrations in PSP patients change over time. Studies in ALS patients have
166
shown stable NfL levels over time,[14, 15] while in patients with primary progressive aphasia, serum
167
NfL increased after one year follow-up.[16] Secondly, many samples were stored at – 80°C for more
168
than 10 years. While the effect of long storage on serum NfL levels is unknown, the NfL
169
concentrations in CSF appeared stable under pre-analytical variations, and no negative effect was
170
observed due to long-term storage or delayed processing.[17] In summary, we demonstrate that
171
serum NfL is a promising, easily accessible biomarker for monitoring disease severity and survival in
172
PSP.
AC C
EP
TE D
M AN U
161
173 174
Acknowledgements:
175
We are very grateful to Peter Koudstaal providing the control samples for this study and reviewing
176
the manuscript. 9
ACCEPTED MANUSCRIPT
177
Financial Disclosures of all authors:
179
-
L. Donker Kaat: Grant from “Bluefield project” and “Alzheimer Nederland”
180
-
L.H. Meeter: Grant from “Alzheimer Nederland”
181
-
W.Z. Chiu: none
182
-
S. Melhem: none
183
-
A.J.W. Boon: Grant from “Stichting Parkinson Fonds”
184
-
K. Blennow has served as a consultant or at advisory boards for Alzheon, BioArctic, Biogen, Eli
-
SC
H. Zetterberg has served at advisory boards for Eli Lilly, Roche Diagnostics and Pharmasum Therapeutics, and has received travel support from TEVA
-
J.C. van Swieten: Grants from “ZonMw dementia research and innovation programme
TE D
187 188
M AN U
Lilly, Fujirebio Europe, IBL International, Merck, Pfizer, and Roche Diagnostics.
185 186
RI PT
178
Memorabel”, “Alzheimer Nederland”, “Dioraphte foundation”, “the European Joint Programme
190
- Neurodegenerative Disease Research and the Netherlands Organisation for Health Research
191
and Development”, “Bluefield Project”
193
AC C
192
EP
189
10
ACCEPTED MANUSCRIPT
References
195
[1] L.H. Meeter, L.D. Kaat, J.D. Rohrer, J.C. van Swieten, Imaging and fluid biomarkers in frontotemporal
196
dementia, Nat Rev Neurol 13(7) (2017) 406-419.
197
[2] J. Kuhle, C. Barro, U. Andreasson, T. Derfuss, R. Lindberg, A. Sandelius, V. Liman, N. Norgren, K. Blennow,
198
H. Zetterberg, Comparison of three analytical platforms for quantification of the neurofilament light chain in
199
blood samples: ELISA, electrochemiluminescence immunoassay and Simoa, Clin Chem Lab Med 54(10) (2016)
200
1655-61.
201
[3] P.S.J. Weston, T. Poole, N.S. Ryan, A. Nair, Y. Liang, K. Macpherson, R. Druyeh, I.B. Malone, R.L. Ahsan, H.
202
Pemberton, J. Klimova, S. Mead, K. Blennow, M.N. Rossor, J.M. Schott, H. Zetterberg, N.C. Fox, Serum
203
neurofilament light in familial Alzheimer disease: A marker of early neurodegeneration, Neurology 89(21)
204
(2017) 2167-2175.
205
[4] L.H. Meeter, E.G. Dopper, L.C. Jiskoot, R. Sanchez-Valle, C. Graff, L. Benussi, R. Ghidoni, Y.A. Pijnenburg, B.
206
Borroni, D. Galimberti, R.J. Laforce, M. Masellis, R. Vandenberghe, I.L. Ber, M. Otto, R. van Minkelen, J.M.
207
Papma, S.A. Rombouts, M. Balasa, L. Oijerstedt, V. Jelic, K.M. Dick, D.M. Cash, S.R. Harding, M. Jorge
208
Cardoso, S. Ourselin, M.N. Rossor, A. Padovani, E. Scarpini, C. Fenoglio, M.C. Tartaglia, F. Lamari, C. Barro, J.
209
Kuhle, J.D. Rohrer, C.E. Teunissen, J.C. van Swieten, Neurofilament light chain: a biomarker for genetic
210
frontotemporal dementia, Ann Clin Transl Neurol 3(8) (2016) 623-36.
211
[5] B. Holmberg, L. Rosengren, J.E. Karlsson, B. Johnels, Increased cerebrospinal fluid levels of neurofilament
212
protein in progressive supranuclear palsy and multiple-system atrophy compared with Parkinson's disease,
213
Mov Disord 13(1) (1998) 70-7.
214
[6] R. Constantinescu, L. Rosengren, B. Johnels, H. Zetterberg, B. Holmberg, Consecutive analyses of
215
cerebrospinal fluid axonal and glial markers in Parkinson's disease and atypical Parkinsonian disorders,
216
Parkinsonism Relat Disord 16(2) (2010) 142-5.
AC C
EP
TE D
M AN U
SC
RI PT
194
11
ACCEPTED MANUSCRIPT
[7] S. Hall, A. Ohrfelt, R. Constantinescu, U. Andreasson, Y. Surova, F. Bostrom, C. Nilsson, W. Hakan, H.
218
Decraemer, K. Nagga, L. Minthon, E. Londos, E. Vanmechelen, B. Holmberg, H. Zetterberg, K. Blennow, O.
219
Hansson, Accuracy of a panel of 5 cerebrospinal fluid biomarkers in the differential diagnosis of patients with
220
dementia and/or parkinsonian disorders, Arch Neurol 69(11) (2012) 1445-52.
221
[8] N.K. Magdalinou, R.W. Paterson, J.M. Schott, N.C. Fox, C. Mummery, K. Blennow, K. Bhatia, H.R. Morris, P.
222
Giunti, T.T. Warner, R. de Silva, A.J. Lees, H. Zetterberg, A panel of nine cerebrospinal fluid biomarkers may
223
identify patients with atypical parkinsonian syndromes, J Neurol Neurosurg Psychiatry 86(11) (2015) 1240-7.
224
[9] J.C. Rojas, A. Karydas, J. Bang, R.M. Tsai, K. Blennow, V. Liman, J.H. Kramer, H. Rosen, B.L. Miller, H.
225
Zetterberg, A.L. Boxer, Plasma neurofilament light chain predicts progression in progressive supranuclear
226
palsy, Ann Clin Transl Neurol 3(3) (2016) 216-25.
227
[10] O. Hansson, S. Janelidze, S. Hall, N. Magdalinou, A.J. Lees, U. Andreasson, N. Norgren, J. Linder, L.
228
Forsgren, R. Constantinescu, H. Zetterberg, K. Blennow, F.s. Swedish Bio, Blood-based NfL: A biomarker for
229
differential diagnosis of parkinsonian disorder, Neurology 88(10) (2017) 930-937.
230
[11] T. Skillback, B. Farahmand, J.W. Bartlett, C. Rosen, N. Mattsson, K. Nagga, L. Kilander, D. Religa, A. Wimo,
231
B. Winblad, L. Rosengren, J.M. Schott, K. Blennow, M. Eriksdotter, H. Zetterberg, CSF neurofilament light
232
differs in neurodegenerative diseases and predicts severity and survival, Neurology 83(21) (2014) 1945-53.
233
[12] T. Skillback, N. Mattsson, K. Blennow, H. Zetterberg, Cerebrospinal fluid neurofilament light
234
concentration in motor neuron disease and frontotemporal dementia predicts survival, Amyotroph Lateral
235
Scler Frontotemporal Degener 18(5-6) (2017) 397-403.
236
[13] L. Donker Kaat, A.J. Boon, W. Kamphorst, R. Ravid, H.J. Duivenvoorden, J.C. van Swieten, Frontal
237
presentation in progressive supranuclear palsy, Neurology 69(8) (2007) 723-9.
238
[14] C.H. Lu, C. Macdonald-Wallis, E. Gray, N. Pearce, A. Petzold, N. Norgren, G. Giovannoni, P. Fratta, K.
239
Sidle, M. Fish, R. Orrell, R. Howard, K. Talbot, L. Greensmith, J. Kuhle, M.R. Turner, A. Malaspina,
AC C
EP
TE D
M AN U
SC
RI PT
217
12
ACCEPTED MANUSCRIPT
Neurofilament light chain: A prognostic biomarker in amyotrophic lateral sclerosis, Neurology 84(22) (2015)
241
2247-57.
242
[15] P. Steinacker, A. Huss, B. Mayer, T. Grehl, J. Grosskreutz, G. Borck, J. Kuhle, D. Lule, T. Meyer, P. Oeckl, S.
243
Petri, J. Weishaupt, A.C. Ludolph, M. Otto, Diagnostic and prognostic significance of neurofilament light chain
244
NF-L, but not progranulin and S100B, in the course of amyotrophic lateral sclerosis: Data from the German
245
MND-net, Amyotroph Lateral Scler Frontotemporal Degener 18(1-2) (2017) 112-119.
246
[16] P. Steinacker, E. Semler, S. Anderl-Straub, J. Diehl-Schmid, M.L. Schroeter, I. Uttner, H. Foerstl, B.
247
Landwehrmeyer, C.A. von Arnim, J. Kassubek, P. Oeckl, H.J. Huppertz, K. Fassbender, K. Fliessbach, J. Prudlo,
248
C. Rossmeier, J. Kornhuber, A. Schneider, A.E. Volk, M. Lauer, A. Danek, A.C. Ludolph, M. Otto, F.T.S. Group,
249
Neurofilament as a blood marker for diagnosis and monitoring of primary progressive aphasias, Neurology
250
88(10) (2017) 961-969.
251
[17] M.J. Koel-Simmelink, A. Vennegoor, J. Killestein, M.A. Blankenstein, N. Norgren, C. Korth, C.E. Teunissen,
252
The impact of pre-analytical variables on the stability of neurofilament proteins in CSF, determined by a
253
novel validated SinglePlex Luminex assay and ELISA, J Immunol Methods 402(1-2) (2014) 43-9.
256 257 258 259
SC
M AN U
TE D
EP
255
AC C
254
RI PT
240
260
13
ACCEPTED MANUSCRIPT
Figure 1.
262
A) Serum NfL levels in PSP patients and controls. Horizontal lines (solid) represent median values.
263
Dotted line (i.e. at 38.3 pg/ml) corresponds to the optimal cut off (sensitivity of 90% and specificity
264
of 63%). Filled black circles indicate PSP patients with pathological confirmation.
265
B) Survival curves for PSP patients with low (green line), intermediate (blue line), and high (red line)
266
NfL levels.
SC
RI PT
261
AC C
EP
TE D
M AN U
267
14
ACCEPTED MANUSCRIPT
Table 1. Demographic and clinical characteristics of PSP patients and controls.
p Value 0.23# 0.003‡
30.6 (20.1-41.1) <0.001†
#
na na na na na na na na na
TE D
M AN U
SC
Gender (% female) Age at serum sampling, years Age at disease onset, years Disease duration at sampling, years (median, range) NfL level, pg/ml (median, interquartile range) 64.2 (42.4-86.1) NINDS-SPSP criteria (n) Possible 49 59 Probable Definite 23 47.2 (15.5) PSP-RS (n=113) Hoehn and Yahr scale (n=116) 4.3 (0.8) 23.9 (4.6) MMSE (n=107)* FAB (n=92) 10.0 (3.5) 119 Deceased subjects (n) 7.8 (3.3) Disease duration from onset till death (years) Numbers are mean (SD) or unless otherwise stated.
Controls (n=95) 54 68.5 (6.3) na na
RI PT
PSP patients (n=131) 45 71.3 (7.7) 66.4 (7.6) 4.4 (14.0)
Chi-square test; ‡ Student T test; † Mann Whitney U test.
EP
*In 20 subjects the maximal possible score was less than 30 due to severe motor disability. NfL= neurofilament light chain; PSP-RS= PSP-Rating Scale; MMSE: Mini Mental State Examination;
AC C
FAB= Frontal Assessment Battery; na= not applicable
1
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
EP
TE D
M AN U
SC
RI PT
Neurofilament light chain is a promising biomarker in neurodegenerative diseases Increased levels are present in serum of patients with PSP Higher levels are associated with greater disease severity and shorter survival
AC C
• • •
S1353-8020(18)30277-3
DOI:
10.1016/j.parkreldis.2018.06.018
Reference:
PRD 3704
To appear in:
Parkinsonism and Related Disorders
Received Date: 10 April 2018 Revised Date:
8 June 2018
Accepted Date: 11 June 2018
Please cite this article as: Kaat LD, Meeter LH, Chiu WZ, BsC SM, Boon AJW, Blennow K, Zetterberg H, van Swieten JC, Serum neurofilament light chain in progressive supranuclear palsy, Parkinsonism and Related Disorders (2018), doi: 10.1016/j.parkreldis.2018.06.018. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
1
Serum neurofilament light chain in progressive supranuclear palsy
2 4 5
Laura Donker Kaat MD, PhD1,2, Lieke H. Meeter MD1, Wan Zheng Chiu MD1, Shami Melhem BsC1, Agnita J.W. Boon MD, PhD1, Kaj Blennow MD, PhD3,4, Henrik Zetterberg MD, PhD3,4,5,6 and John C. van Swieten MD, PhD1,7
RI PT
3
6 7
1
8
2
11 12 13 14 15 16
SC
10
M AN U
9
Department of Neurology, Erasmus Medical Center Rotterdam, the Netherlands Department of Clinical Genetics, Leiden University Medical Center, the Netherlands 3 Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Sahlgrenska University Hospital, Mölndal, Sweden 4 Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden 5 Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, United Kingdom 6 UK Dementia Research Institute at UCL, London, United Kingdom 7 Department of Clinical Genetics, VU Medical Center Amsterdam, the Netherlands
17 18 19
Corresponding author:
20
TE D
21 22 23 24
EP
25
Word count:
27
Key words:
28
Funding sources for study:
AC C
26
29 30 31
Laura Donker Kaat Erasmus MC, Department of Neurology, Ee2293 Postbus 2040, 3000 CA Rotterdam The Netherlands +31-(0)10-7043828 email: [email protected] 1563
neurofilament, biomarker, progressive supranuclear palsy
Prinses Beatrix Fonds
1
ACCEPTED MANUSCRIPT
ABSTRACT
33
Introduction Neurofilament light chain (NfL) is a promising biomarker in neurodegenerative
34
diseases. Elevated NfL levels in CSF and blood have been observed in a growing number of
35
neurodegenerative disorders, including frontotemporal dementia and Alzheimer’s disease. We
36
studied serum NfL levels in patients with progressive supranuclear palsy (PSP) in relation to disease
37
severity and survival.
38
Methods Serum NfL levels were determined cross-sectionally in a retrospective cohort of 131
39
patients with PSP and 95 healthy controls. Detailed clinical examination was performed and disease
40
severity was assessed by several rating scales.
41
Results We found that serum NfL levels in PSP were twice as high as those in controls, and that NfL
42
levels correlated with worse functional, motor and cognitive functioning. During follow-up, 119 PSP
43
patients had died, and higher NfL levels were associated with a shorter survival.
44
Conclusion This study provides evidence that serum NfL is a relevant and promising biomarker in
45
PSP for disease severity, and may be used as a prognostic tool to predict survival in clinical practice.
SC
M AN U
TE D
EP AC C
46
RI PT
32
2
ACCEPTED MANUSCRIPT
INTRODUCTION
48
There is an urgent need for sensitive, easily accessible biomarkers in neurodegenerative disorders
49
to monitor both disease progression and the effects of treatment. Elevated levels of neurofilament
50
light chain (NfL), a neuronal cytoskeletal protein, reflect neuronal injury and have been found in the
51
cerebral spinal fluid (CSF) of patients with several neurodegenerative disorders.[1] An important
52
recent finding is that NfL levels can be reliably measured in blood, and that these correlate well
53
with NfL levels in CSF.[2]. In familial AD [3], but not in familial FTD [4], serum concentrations of NfL
54
are already increased prior to symptom onset, indicating an early disease marker in certain
55
neurodegenerative disorders.
56
Progressive supranuclear palsy (PSP) is a neurodegenerative disorder characterized by
57
parkinsonism, frequent falls, supranuclear gaze palsy and widespread tau positive inclusions at
58
brain autopsy. Elevated NfL levels have been found in PSP patients’ CSF.[5-8] Blood NfL has recently
59
been shown to be a useful biomarker for assessing disease severity and predicting disease
60
progression in PSP patients.[9] In addition, blood NfL has a good diagnostic performance in the
61
discrimination of atypical parkinsonism (including PSP) from Parkinson’s disease.[10] Elevated NfL is
62
however not specific to PSP as increased levels have also been found in several other
63
neurodegenerative diseases. NfL levels have been associated with survival in frontotemporal
64
dementia (FTD), Alzheimer’s disease (AD) and amyotrophic lateral sclerosis (ALS).[4, 11, 12] This
65
prognostic value has not been studied in PSP, except for a small study of 12 patients where
66
mortality at 24-month follow up was associated with high CSF NfL levels.[5]
AC C
EP
TE D
M AN U
SC
RI PT
47
3
ACCEPTED MANUSCRIPT
In this retrospective case-control study, we investigated serum NfL levels in a large and well
68
characterized cohort of PSP patients, demonstrating its relationship with disease severity and
69
survival.
70
METHODS
71
Subjects
72
PSP patients were enrolled between 2003 and 2014 as part of a Dutch genetic epidemiological PSP
73
study.[13] The study was approved by the Medical Ethical committee of Erasmus MC; all
74
participants or legal representatives signed informed consent. Inclusion in the study took place at
75
the out-patients clinic, or by visiting patients at home or in nursing homes. At study entry, detailed
76
clinical assessment was performed, including an interview with the care-giver and an extensive
77
neurological examination with the assessment of the following rating scales: PSP-rating scale (PSP-
78
RS), Mini Mental State Examination (MMSE), Frontal Assessment Battery (FAB), Hoehn and Yahr
79
(HY) scale and Schwab and England Activities of Daily Living (SEADL). In a consensus meeting,
80
clinical data were reviewed, and the diagnosis PSP was established according to the National
81
Institute for Neurological Disorders and Society for PSP (NINDS-SPSP) criteria. Controls were healthy
82
spouses or caregivers from stroke patients, above 55 years of age and randomly selected from a
83
large database.
SC
M AN U
TE D
EP
AC C
84
RI PT
67
85
NfL measurement
86
Blood sampling from PSP patients was carried out at the time of study entry when clinical
87
assessment was performed. Serum samples from PSP patients and controls were centrifuged the
88
same day and stored at -80°C in aliquots. For the analysis, we used one aliquot, that underwent
4
ACCEPTED MANUSCRIPT
only one thaw/freeze cycle. We used a recently developed, ultrasensitive Simoa assay to measure
90
the sample NfL levels.[2] The measurements were performed in one round of experiments using
91
one batch of reagents by board-certified technicians who were blinded to clinical data. For a quality
92
control sample with a concentration of 16.8 pg/ml, repeatability was 7.36% and intermediate
93
precision was 7.43%. For a quality control sample with a concentration of 127 pg/ml, repeatability
94
was 6.69% and intermediate precision was 8.24%.
SC
RI PT
89
95
Statistical analysis
97
Differences in demographics between cases and controls were analyzed using parametric and non-
98
parametric statistics as appropriate (SPSS version 21.0).
99
Six subjects (2 controls and 4 cases) with extremely high NfL values (>2 SD above the mean) were
100
considered as outliers and their NfL values were replaced by values corresponding to the upper 2
101
SD cut off. Because of non-normality, log transformation of NfL data was performed. Age was
102
correlated with NfL levels in both cases (Spearman’s rho=0.37, p<0.001) and controls (Spearman’s
103
rho=0.55, p<0.001). We conducted therefor an ANCOVA to analyze NfL levels between cases and
104
controls adjusted for age. The diagnostic accuracy of NfL was examined using receiver operating
105
characteristic (ROC) curve analysis, with optimal cut off according to Youden’s index. Correlations
106
between NfL and disease severity (measured by PSP-RS, MMSE, FAB, SEADL and HY scale) were
107
studied using linear regression analyses, with age and gender as covariates.
108
During follow up, 119 PSP patients had died and survival time was calculated from the moment of
109
serum collection till date of death. In twelve patients the deceased status was unknown and in
110
these subjects survival time was calculated from the moment of serum collection till last contact
AC C
EP
TE D
M AN U
96
5
ACCEPTED MANUSCRIPT
111
alive and entered as censored data. Survival in PSP patients was compared between NfL tertiles by
112
Kaplan-Meier curves with log-rank tests and Cox regressions adjusted for age and gender.
AC C
EP
TE D
M AN U
SC
RI PT
113
6
ACCEPTED MANUSCRIPT
RESULTS
115
Serum NfL levels were determined in 131 PSP patients and 95 controls. PSP patients showed
116
significantly higher NfL levels compared to controls (Table 1 and Figure 1A). This significance held
117
after correction for age and sex on log-transformed NfL (p<0.001). We were able to accurately
118
distinguish PSP patients from controls using serum NfL (area under the curve 0.87, 95% confidence
119
interval 0.83-0.92). A cutoff value of 38.3 pg/ml provided a sensitivity of 90% and specificity of 63%.
120
During follow-up, 23 patients underwent brain autopsy and in all cases the diagnosis PSP was
121
confirmed (filled black circles in figure 1A).
SC
M AN U
122
RI PT
114
Significant correlations were found between NfL levels and PSP-RS sum scores (β= 0.37, p<0.001), SEADL scores (β= -0.32, p=0.001), HY scale (β=0.30, p=0.001), FAB scores (β= -0.29,
124
p=0.004) and MMSE scores (β= -0.18, p=0.05), indicating that higher NfL levels are associated with
125
more severe motor, functional and cognitive disability. No associations were found between NfL
126
levels and age at symptom onset or disease duration from onset till serum collection.
127
TE D
123
PSP-patients with higher NfL levels showed worse survival (Log Rank test p<0.001, Figure 1B). After adjusting for age and sex, NfL levels remained significantly associated with worse survival
129
(Hazard Ratio 1.5 [1.1-1.9], p=0.003).
131
AC C
130
EP
128
7
ACCEPTED MANUSCRIPT
DISCUSSION
133
This cross-sectional study shows that serum NfL levels are elevated in PSP patients, and that these
134
are associated with disease severity and survival. Serum NfL is thus a promising biomarker in PSP
135
with the major advantages over CSF that sample collection is minimally invasive and can be easily
136
repeated over time. Because of the association with disease severity and survival, serum NfL may
137
serve as a prognostic tool in clinical practice. Additionally, it can facilitate study design for
138
therapeutic trials and genetic studies to categorize patients into disease subtypes.
139
The NfL concentrations in PSP patients were twice as high as those in controls, which is similar the
140
results from two previous studies on blood-based NfL in PSP.[9, 10] We further demonstrate that
141
NfL levels correlate with motor, cognitive and functional disability in PSP, at least at a cross
142
sectional level in this study. Comparably, a previous study showed that blood NfL levels were
143
correlated with Hoehn and Yahr stage and UPDRS-III motor scores,[10] while in another study, high
144
baseline NfL levels were associated with a more rapid neurological, functional and
145
neuropsychological decline.[9] In addition to this, we show that high serum NfL levels are
146
associated with shorter survival. This prognostic value, has been demonstrated for NfL in a few
147
other neurodegenerative diseases, but usually measured in CSF[4, 11, 12], whereas in blood, this
148
association has only been demonstrated in ALS and FTD patients so far.[4, 14, 15]
149
Absolute NfL concentrations differed between our cohort and previous studies, which has been
150
observed before.[10] There are many factors which may explain this difference such as age, disease
151
severity, sampling or storage effects, inter-laboratory variation and the application of serum versus
152
plasma. Before the implementation of NfL in clinical practice, standardized procedures with uniform
153
protocols across sites and the establishment of cut-off levels are necessary.
AC C
EP
TE D
M AN U
SC
RI PT
132
8
ACCEPTED MANUSCRIPT
In 23 individuals (18%), the diagnosis PSP was confirmed at autopsy and these patients showed mild
155
to strongly increased NfL levels, not different from clinically diagnosed PSP patients (Figure 1A). A
156
few PSP patients showed extremely high NfL levels. It is possible that other comorbidities (such as a
157
minor stroke or head trauma) may have influenced NfL levels at that time in these patients. The
158
presence of high NfL values in a few control subjects remains unresolved, as we have no additional
159
clinical information or neuroimaging data.
SC
RI PT
154
The strengths of the current study are the large sample size with substantial pathological
160
confirmation, a clinically well characterized cohort with the assessment of several rating scales, and
162
the long period of follow-up, including information on survival. We also acknowledge some
163
limitations. First, this study relies on cross-sectional acquired data, with many patients at an
164
advanced disease stage. Longitudinal data would have been valuable in helping to determine
165
whether and how NfL concentrations in PSP patients change over time. Studies in ALS patients have
166
shown stable NfL levels over time,[14, 15] while in patients with primary progressive aphasia, serum
167
NfL increased after one year follow-up.[16] Secondly, many samples were stored at – 80°C for more
168
than 10 years. While the effect of long storage on serum NfL levels is unknown, the NfL
169
concentrations in CSF appeared stable under pre-analytical variations, and no negative effect was
170
observed due to long-term storage or delayed processing.[17] In summary, we demonstrate that
171
serum NfL is a promising, easily accessible biomarker for monitoring disease severity and survival in
172
PSP.
AC C
EP
TE D
M AN U
161
173 174
Acknowledgements:
175
We are very grateful to Peter Koudstaal providing the control samples for this study and reviewing
176
the manuscript. 9
ACCEPTED MANUSCRIPT
177
Financial Disclosures of all authors:
179
-
L. Donker Kaat: Grant from “Bluefield project” and “Alzheimer Nederland”
180
-
L.H. Meeter: Grant from “Alzheimer Nederland”
181
-
W.Z. Chiu: none
182
-
S. Melhem: none
183
-
A.J.W. Boon: Grant from “Stichting Parkinson Fonds”
184
-
K. Blennow has served as a consultant or at advisory boards for Alzheon, BioArctic, Biogen, Eli
-
SC
H. Zetterberg has served at advisory boards for Eli Lilly, Roche Diagnostics and Pharmasum Therapeutics, and has received travel support from TEVA
-
J.C. van Swieten: Grants from “ZonMw dementia research and innovation programme
TE D
187 188
M AN U
Lilly, Fujirebio Europe, IBL International, Merck, Pfizer, and Roche Diagnostics.
185 186
RI PT
178
Memorabel”, “Alzheimer Nederland”, “Dioraphte foundation”, “the European Joint Programme
190
- Neurodegenerative Disease Research and the Netherlands Organisation for Health Research
191
and Development”, “Bluefield Project”
193
AC C
192
EP
189
10
ACCEPTED MANUSCRIPT
References
195
[1] L.H. Meeter, L.D. Kaat, J.D. Rohrer, J.C. van Swieten, Imaging and fluid biomarkers in frontotemporal
196
dementia, Nat Rev Neurol 13(7) (2017) 406-419.
197
[2] J. Kuhle, C. Barro, U. Andreasson, T. Derfuss, R. Lindberg, A. Sandelius, V. Liman, N. Norgren, K. Blennow,
198
H. Zetterberg, Comparison of three analytical platforms for quantification of the neurofilament light chain in
199
blood samples: ELISA, electrochemiluminescence immunoassay and Simoa, Clin Chem Lab Med 54(10) (2016)
200
1655-61.
201
[3] P.S.J. Weston, T. Poole, N.S. Ryan, A. Nair, Y. Liang, K. Macpherson, R. Druyeh, I.B. Malone, R.L. Ahsan, H.
202
Pemberton, J. Klimova, S. Mead, K. Blennow, M.N. Rossor, J.M. Schott, H. Zetterberg, N.C. Fox, Serum
203
neurofilament light in familial Alzheimer disease: A marker of early neurodegeneration, Neurology 89(21)
204
(2017) 2167-2175.
205
[4] L.H. Meeter, E.G. Dopper, L.C. Jiskoot, R. Sanchez-Valle, C. Graff, L. Benussi, R. Ghidoni, Y.A. Pijnenburg, B.
206
Borroni, D. Galimberti, R.J. Laforce, M. Masellis, R. Vandenberghe, I.L. Ber, M. Otto, R. van Minkelen, J.M.
207
Papma, S.A. Rombouts, M. Balasa, L. Oijerstedt, V. Jelic, K.M. Dick, D.M. Cash, S.R. Harding, M. Jorge
208
Cardoso, S. Ourselin, M.N. Rossor, A. Padovani, E. Scarpini, C. Fenoglio, M.C. Tartaglia, F. Lamari, C. Barro, J.
209
Kuhle, J.D. Rohrer, C.E. Teunissen, J.C. van Swieten, Neurofilament light chain: a biomarker for genetic
210
frontotemporal dementia, Ann Clin Transl Neurol 3(8) (2016) 623-36.
211
[5] B. Holmberg, L. Rosengren, J.E. Karlsson, B. Johnels, Increased cerebrospinal fluid levels of neurofilament
212
protein in progressive supranuclear palsy and multiple-system atrophy compared with Parkinson's disease,
213
Mov Disord 13(1) (1998) 70-7.
214
[6] R. Constantinescu, L. Rosengren, B. Johnels, H. Zetterberg, B. Holmberg, Consecutive analyses of
215
cerebrospinal fluid axonal and glial markers in Parkinson's disease and atypical Parkinsonian disorders,
216
Parkinsonism Relat Disord 16(2) (2010) 142-5.
AC C
EP
TE D
M AN U
SC
RI PT
194
11
ACCEPTED MANUSCRIPT
[7] S. Hall, A. Ohrfelt, R. Constantinescu, U. Andreasson, Y. Surova, F. Bostrom, C. Nilsson, W. Hakan, H.
218
Decraemer, K. Nagga, L. Minthon, E. Londos, E. Vanmechelen, B. Holmberg, H. Zetterberg, K. Blennow, O.
219
Hansson, Accuracy of a panel of 5 cerebrospinal fluid biomarkers in the differential diagnosis of patients with
220
dementia and/or parkinsonian disorders, Arch Neurol 69(11) (2012) 1445-52.
221
[8] N.K. Magdalinou, R.W. Paterson, J.M. Schott, N.C. Fox, C. Mummery, K. Blennow, K. Bhatia, H.R. Morris, P.
222
Giunti, T.T. Warner, R. de Silva, A.J. Lees, H. Zetterberg, A panel of nine cerebrospinal fluid biomarkers may
223
identify patients with atypical parkinsonian syndromes, J Neurol Neurosurg Psychiatry 86(11) (2015) 1240-7.
224
[9] J.C. Rojas, A. Karydas, J. Bang, R.M. Tsai, K. Blennow, V. Liman, J.H. Kramer, H. Rosen, B.L. Miller, H.
225
Zetterberg, A.L. Boxer, Plasma neurofilament light chain predicts progression in progressive supranuclear
226
palsy, Ann Clin Transl Neurol 3(3) (2016) 216-25.
227
[10] O. Hansson, S. Janelidze, S. Hall, N. Magdalinou, A.J. Lees, U. Andreasson, N. Norgren, J. Linder, L.
228
Forsgren, R. Constantinescu, H. Zetterberg, K. Blennow, F.s. Swedish Bio, Blood-based NfL: A biomarker for
229
differential diagnosis of parkinsonian disorder, Neurology 88(10) (2017) 930-937.
230
[11] T. Skillback, B. Farahmand, J.W. Bartlett, C. Rosen, N. Mattsson, K. Nagga, L. Kilander, D. Religa, A. Wimo,
231
B. Winblad, L. Rosengren, J.M. Schott, K. Blennow, M. Eriksdotter, H. Zetterberg, CSF neurofilament light
232
differs in neurodegenerative diseases and predicts severity and survival, Neurology 83(21) (2014) 1945-53.
233
[12] T. Skillback, N. Mattsson, K. Blennow, H. Zetterberg, Cerebrospinal fluid neurofilament light
234
concentration in motor neuron disease and frontotemporal dementia predicts survival, Amyotroph Lateral
235
Scler Frontotemporal Degener 18(5-6) (2017) 397-403.
236
[13] L. Donker Kaat, A.J. Boon, W. Kamphorst, R. Ravid, H.J. Duivenvoorden, J.C. van Swieten, Frontal
237
presentation in progressive supranuclear palsy, Neurology 69(8) (2007) 723-9.
238
[14] C.H. Lu, C. Macdonald-Wallis, E. Gray, N. Pearce, A. Petzold, N. Norgren, G. Giovannoni, P. Fratta, K.
239
Sidle, M. Fish, R. Orrell, R. Howard, K. Talbot, L. Greensmith, J. Kuhle, M.R. Turner, A. Malaspina,
AC C
EP
TE D
M AN U
SC
RI PT
217
12
ACCEPTED MANUSCRIPT
Neurofilament light chain: A prognostic biomarker in amyotrophic lateral sclerosis, Neurology 84(22) (2015)
241
2247-57.
242
[15] P. Steinacker, A. Huss, B. Mayer, T. Grehl, J. Grosskreutz, G. Borck, J. Kuhle, D. Lule, T. Meyer, P. Oeckl, S.
243
Petri, J. Weishaupt, A.C. Ludolph, M. Otto, Diagnostic and prognostic significance of neurofilament light chain
244
NF-L, but not progranulin and S100B, in the course of amyotrophic lateral sclerosis: Data from the German
245
MND-net, Amyotroph Lateral Scler Frontotemporal Degener 18(1-2) (2017) 112-119.
246
[16] P. Steinacker, E. Semler, S. Anderl-Straub, J. Diehl-Schmid, M.L. Schroeter, I. Uttner, H. Foerstl, B.
247
Landwehrmeyer, C.A. von Arnim, J. Kassubek, P. Oeckl, H.J. Huppertz, K. Fassbender, K. Fliessbach, J. Prudlo,
248
C. Rossmeier, J. Kornhuber, A. Schneider, A.E. Volk, M. Lauer, A. Danek, A.C. Ludolph, M. Otto, F.T.S. Group,
249
Neurofilament as a blood marker for diagnosis and monitoring of primary progressive aphasias, Neurology
250
88(10) (2017) 961-969.
251
[17] M.J. Koel-Simmelink, A. Vennegoor, J. Killestein, M.A. Blankenstein, N. Norgren, C. Korth, C.E. Teunissen,
252
The impact of pre-analytical variables on the stability of neurofilament proteins in CSF, determined by a
253
novel validated SinglePlex Luminex assay and ELISA, J Immunol Methods 402(1-2) (2014) 43-9.
256 257 258 259
SC
M AN U
TE D
EP
255
AC C
254
RI PT
240
260
13
ACCEPTED MANUSCRIPT
Figure 1.
262
A) Serum NfL levels in PSP patients and controls. Horizontal lines (solid) represent median values.
263
Dotted line (i.e. at 38.3 pg/ml) corresponds to the optimal cut off (sensitivity of 90% and specificity
264
of 63%). Filled black circles indicate PSP patients with pathological confirmation.
265
B) Survival curves for PSP patients with low (green line), intermediate (blue line), and high (red line)
266
NfL levels.
SC
RI PT
261
AC C
EP
TE D
M AN U
267
14
ACCEPTED MANUSCRIPT
Table 1. Demographic and clinical characteristics of PSP patients and controls.
p Value 0.23# 0.003‡
30.6 (20.1-41.1) <0.001†
#
na na na na na na na na na
TE D
M AN U
SC
Gender (% female) Age at serum sampling, years Age at disease onset, years Disease duration at sampling, years (median, range) NfL level, pg/ml (median, interquartile range) 64.2 (42.4-86.1) NINDS-SPSP criteria (n) Possible 49 59 Probable Definite 23 47.2 (15.5) PSP-RS (n=113) Hoehn and Yahr scale (n=116) 4.3 (0.8) 23.9 (4.6) MMSE (n=107)* FAB (n=92) 10.0 (3.5) 119 Deceased subjects (n) 7.8 (3.3) Disease duration from onset till death (years) Numbers are mean (SD) or unless otherwise stated.
Controls (n=95) 54 68.5 (6.3) na na
RI PT
PSP patients (n=131) 45 71.3 (7.7) 66.4 (7.6) 4.4 (14.0)
Chi-square test; ‡ Student T test; † Mann Whitney U test.
EP
*In 20 subjects the maximal possible score was less than 30 due to severe motor disability. NfL= neurofilament light chain; PSP-RS= PSP-Rating Scale; MMSE: Mini Mental State Examination;
AC C
FAB= Frontal Assessment Battery; na= not applicable
1
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
EP
TE D
M AN U
SC
RI PT
Neurofilament light chain is a promising biomarker in neurodegenerative diseases Increased levels are present in serum of patients with PSP Higher levels are associated with greater disease severity and shorter survival
AC C
• • •