Biomarkers in alzheimers

Basic Science applied to medicine

1. Introduction
•Alzheimer’s disease (AD)
•Biomarkers definition
Biomarkers for AD
 Biomarkers in CSF
 Biomarkers in Blood
 Genetic biomarkers
Techniques for detect biomarkers
- ELISA
- miRNA microarray and RT-PCR
- MS
Conclusion
overview

2. “Re”- defining Alzheimer’s disease
AD is a progressive neurodegenerative disorder that culminates
in end-organ (brain) failure which manifests as dementia.
AD can be conceptualized as having two major stages:
1) Preclinical (pre-symptomatic)
2) Symptomatic - Prodromal (incipient/MCI)
- Dementia of the Alzheimer type

3. Amyloid-beta metabolism and related neurotoxic cascades
J.L. Cummings / Alzheimer’s & Dementia 7 (2011) e13–e44

4. •A biomarker is an object that measured and evaluated
as an indicator of normal biologic processes,
pathogenic processes or pharmacologic responses to
therapeutic intervention
What is a biomarker?
Biomarker
Detect disease
Stage disease
Monitor
progression/
recurrence
Treatment
efficacy
Response to
treatment

5. Longitudinal changes of Alzheimer disease
biomarkers during the disease progression.
Babić et al: CSF core and developing biomarkers in diagnosis of AD, Croat Med J. 2014;55:347-65

6. Characteristics of Alzheimer disease (AD)
biomarkers
Babić et al: CSF core and developing biomarkers in diagnosis of AD, Croat Med J. 2014;55:347-65

7. Biomarkers for AD in CSF

Diagnostic usefulness of established Alzheimer disease biomarkers
Babić et al: CSF core and developing biomarkers in diagnosis of AD, Croat Med J. 2014;55:347-65

8. Genetic markers - 1
•Mutations in the genes encoding amyloid
precursor protein (APP), presenilin 1
(PSEN1) and presenilin 2 (PSEN2) are
responsible for early-onset autosomal
dominant AD
•more than 30 different APP missense
mutations have been identified and
approximately 25 of these are pathogenic,
in most cases resulting in autosomal
dominant early-onset AD.
•A673V – autosomal recessive AD
•A673T – strong protective effect

9. Genetic markers - 2
•Mutations in PSEN1 are the most common
cause of early-onset AD and account for
18–50% of autosomal dominant early-onset
AD
•Missense mutations in the PSEN2 gene
causing early-onset AD are rare and show
an older age of onset compared with
PSEN1

10. Genetic markers - 3
•APOE isoforms are also related with AD
•APOE E4 allele increases the risk of
sporadic late-onset AD
•circulating microRNAs (miRNAs) in the
cerebrospinal fluid (CSF) and blood serum
of AD patients can be used as biomarkers
in AD diagnosis

11. Technology for AD biomarkers
Analytical method Biomarker
ELISA Aβ42, tau, proteins
miRNA qPCR array
miRNA (e.g. miR-125b, miR-132
family, miR-134 family, etc)
Mass Spectrometry Aβ species, proteins markers
DNA/RNA chips,
GeneChips
Genetic markers

12. ELISA
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13. Internationally established biomarkers in CSF used
to diagnose AD
Humpel, C. Trends in Biotechnology, Jan 2011, vol.29, No.1

14. Aβ in CSF
 CSF Aβ42 shows a highly significant
reduction in AD patients.
 level of shorter Aβ40 is unchanged or
inceased in AD.
 it is suggested that Aβ42/Aβ40 ratio can
improve AD diagnosis.

 Plasma levels of Aβ are increased in familial
AD and Down syndrome.
 But results are inconsistent.
 So plasma Aβ level is not specific for early
diagnosis.

15. Tau in CSF
 Total tau is the second hallmark of AD.
 total tau in CSF increase with age.
 It significantly enhance in AD patients as
compared with age control subjects.
 Phosphorylated tau also increase in AD.

 Tau-related biomarkers in peripheral blood do
not seem to be useful in AD

16. miRNA in AD
•Many previous studies have documented that a
number of miRNA (such as miR-9, miR-29a,
miR-29b, miR101, miR-125b and miR-181c)
were dysregulated in AD brain.
•They play a vital role in pathogenesis of AD.

– miRNA are proposed to be a novel
biomarkers for AD diagnosis.

17. miRNA qPCR array
http://www.tebu-bio.com/?module=tech-
info&id_cms=892&type_cms=3#.VN4OhgEv8V0

18. http://www.tebu-bio.com/?module=tech-
info&id_cms=892&type_cms=3#.VN4OhgEv8V
miRNA qPCR array

19. Validation by RT-PCR
http://www.ncbi.nlm.nih.gov/core/lw/2.0/html
/tileshop_pmc/tileshop_pmc_inline.html?

20. MS base biomarkers - 1
S.Lista et al. / Progress in Neurobiology 101–102 (2013) 1–17

21. MS base biomarkers - 2
S.Lista et al. / Progress in Neurobiology 101–102 (2013) 1–17

22. MS base biomarkers - 3
S.Lista et al. / Progress in Neurobiology 101–102 (2013) 1–17

23. MS base biomarkers - 4
S.Lista et al. / Progress in Neurobiology 101–102 (2013) 1–17
•ELISA
•WB
•RIA

24. Interpretation
•Analyze protein of upregulated and
downregulated
•Various types of protein based on
method of MS
•Proteins are concerned with
inflammatory pathway, immune
regulation , lipid peroxidation, apotosis
and neuroprotective activity, etc
•Currently, no proteins have been
satisfactorily recognized as AD marker

25. Conclusion - 1
•CSF biomarkers like Aβ (1-42) and tau (total
tau and phospho-tau) allows reliable,
sensitive and specific diagnosis of AD.
•But lumbar puncture and collection of CSF
is an invasive treatment with potential side
effects.
•Follow-up analysis is difficult.
•Although saliva and urine can be easily
collected, blood is the gold standard.

26. Conclusion - 2
•Blood plasma levels of Aβ proteins and tau
are inconsistent with sporadic AD.
•Circulating miRNAs are stable, reproducible
and possible candidates for novel non-
invasive biomarkers of AD.
•Proteins have a high potential as dynamic
biomarkers for diagnosis, prediction and
monitoring the development of the disease.

27. Conclusion - 3
•Efforts are underway to discover reliable
blood biomarkers.
•Early, fast and cheap diagnosis using
modern, ultrasensitive analytical methods
(e.g. microarrays or MS) will become
important for future diagnosis of AD.