Cleveland Heartlab 5th Annual Symposium: Jerry Shay, Telomere Testing: An Independent Biomarker for Assessing Cardiovascular Risk

1. TELOMERE TESTING
An Independent Biomarker for Assessing Cardiovascular Risk
International New York Times
Dr. Jerry W. Shay
Distinguished Chair in Geriatrics Research
UT Southwestern Medical Center (Dallas, Texas)
September 12, 2014

2. Disclosures
Scientific Advisory Boards:
• Life Length Inc., Madrid Spain
• Reata Pharmaceuticals Inc., Irving, Texas
• Center of Excellence in Genomic Medicine, Jeddah, Saudi Arabia
Founding Scientist:
• Elizabeth Therapeutics Inc., Dallas, Texas

3. Telomeres Progressively Shorten in all Human Cells
that Divide: The End Replication Problem
Chromosomes are Capped by Telomeres
TELO (end) MERE (segment)
Telomere shortening
Telomere repeat
cell divisions
Senescence

4. Normal Cells Have a Limited Capacity to Divide
STOP
The limited capacity for cells to divide is
known as the Hayflick limit
STOP
STOP
STOP
STOP
STOP
STOP
STOP
Hayflick, 1950s
Short telomeres correlate with replicative senescence
Source: Harley et al, Nature, 1990

5. Normal Tissues Show Progressive Telomere Shortening
Tissue Source Telomere Length (kb)
Sperm
Placenta
Fetal brain
Fetal kidney
Colon mucosa (30-65 yrs)
Colon mucosa (65-88 yrs)
Blood (20-39 yrs)
Blood (40-59 yrs)
Blood (60-79 yrs)
0 4 8 12 16 20 (kb)
Short telomeres correlate with increased age
Source: N. Hasti, R. Allshire Nature, 346:866, 1990

6. Normal Blood Cells (Lymphocytes) Show Progressive
Telomere Shortening
Telomere length (Kb)
0 10 20 30 40 50 60 70 80 90 100
Age (years)
n = 835
14
12
10
8
6
4
2
0
Source: Aubert et al., Plos Genetics, 2012

7. Why Should You Care About Telomeres?

8. Adverse Consequences of Short Telomeres
•Loss of tissue renewal capacity; failure of stem cells
to divide in sufficient numbers
•Senescence-associated secretory phenotype
(SASP)
- “Inflammaging” (increased inflammation)
- Decreased immune responses
•Increased risk of cancer (genomic instability) and
cardiovascular disease

9. Telomere Hypothesis of Aging and Cancer
• Most pre-malignant tissues have very short telomeres
– Telomere attrition may initially be a cancer suppressor
pathway but in combination with other cellular alterations may
drive genomic instability
• Cancer cells are almost always immortal
– Must engage a mechanism for stabilizing telomere length for
the growth of the advanced tumor

10. hTERT
Telomere
hTR
template
hTERT = human telomerase reverse transcriptase
(expressed in cancer cells and some normal stem cells)
hTR/hTERC = human telomerase template RNA
(constituitively expressed but up regulated in cancer)
Normal
Cancer
TRAP
ITAS
Normal Cancer
hTERT
GAPDH
Telomerase is Detected in ~90% Human Cancers
Telomerase is a molecular motor that adds new DNA onto the ends of telomeres

11. Lasker Award for Basic Science 2006
Nobel Prize in Medicine 2009
Elizabeth Blackburn Jack Szostak Carol Greider
Laskerfoundation.org
September 17, 2006
“For the prediction and discovery of telomerase, a RNA-containing
enzyme that synthesizes the ends of chromosomes,
protecting them and maintaining the integrity of the genome.”

12. Telomerase Expression is Sufficient to Elongate
Telomeres and Immortalize Normal Cells Without
Causing Cancer
hTERT +
0 50 100 150 200 250 300
160
140
120
100
80
60
40
Population Doublings
Days
hTERT -
28
48
66
84
104
PD
30 kb
7.7 kb
TRF
Terminal restriction fragments
Telomerase is expressed in some stem cells but is not in excess
and telomeres progressively shorten in all dividing cells
Note: PD = population doubling
Source: Bodnar, A.G., et al. Science, 279:349-352, 1998.

13. Telomeropathies: Genetic Mutations in Telomerase
Mutations in telomerase leads to premature stem
cell depletion and clinical disease.
Health
Disease risk
Age (years)
Telomere length
30-40 70-80

14. Inflammation and Stress Can Modify Telomere Length
Oxidative stress
DNA damage Inflammation
Telomere shortening
Contributes to CVD

15. Diet and Nutrition Can Modify Telomere Length
Omega 3
polyphenols
Vitamins
C & E
Oxidative stress
DNA damage Inflammation
Telomere
shortening
Vitamins
A & D

16. Stress, Diet, Inflammation Leads to Oxidative DNA Damage
and Can Accelerate Telomere Shortening
Health
Disease risk
Age (years)
Telomere length
50-60 70-80
Short telomeres: higher risk of diseases (cardiovascular, neurodegenerative, infections)

17. Sedentary Behavior Can Accelerate Telomere Shortening
Health
Disease risk
Age (years)
Telomere length
50-60 70-80
British Journal of Sports Medicine
September 3, 2014
Short telomeres: higher risk of diseases (cardiovascular, neurodegenerative, infections)

18. Influence of Telomeres on Cardiovascular Health
• Reduced telomere lengths are found in patients with
cardiovascular risk factors such as:
• atherosclerosis
• hypertension
• obesity
• diabetes
• smoking
• physical inactivity
• stress
• chronic infections
• Shorter telomeres have been associated with poor survival.
• A positive effect on telomere length is found with increased
physical activity, statin treatment, and higher blood levels of
omega-3 fatty acids.

19. Will Telomere Length Modification Delay Aging and the
Onset of Age-Related Diseases?
Health
Disease risk
Age (years)
Telomere length
70-80 90-100

20. Association Between Telomere Length in Blood and
Mortality in People Aged 60 Years and Older
• 143 Utah residents (60-97) donated blood between 1982-
1986.
• Those with shorter telomeres had poorer survival attributed to
a 3-fold higher mortality rate from heart disease and a 8.5-
fold higher mortality rate from infectious disease.
• Telomeres may serve as a useful indicator of progression of
age-related disease.
Source: Cawthon et al, Lancet 2003

21. Telomere Length as a Biomarker of Stress and Depression

22. Telomere Length Measurements as a Diagnostic Tool of
Human Disease Risk Assessment
Association Reference
Myocardial infarction Brouilette et al., 2003
Atherosclerosis Benetos et al., 2004
Dementia after stroke or
cardiovascular comorbidity
Von Zglinicki et al., 2000
Mortality
Cawthorn et al., 2003; Martin-
Ruiz et al., 2005
Mortality (in relation to APOEε4 and
dementia)
Honig et al., 2006
Psychological stress Epel et al., 2004

23. An Inverse Association Between Telomere Length
and Risk of Coronary Heart Disease is an
Independent Prognostic Risk Factor
Brit Med J: July, 2014 24 studies, 43,725 participants, 8,400 patients with CVD
Source: Haycock et al. Brit Med J 349: (July 2014)

24. Coronary Heart Disease, Statins and Telomere Length
6.10
6.05
6.00
5.95
Telomere length (Kb)
*P 0.028
No statin
n = 140
Source: Boccardi et al., FASEB, 2013 (edited)
*
Statin
n = 90
Probability of a CVD Event
3.0
2.5
2.0
1.5
1.0
0.5
0
Placebo Pravastatin
Telomere Length
Source: Brouilette et al., Lancet, 2007
Statins may extend lives by not only lowering cholesterol levels but also protecting
against telomere shortening, thus reducing the risk of cardiovascular disease.
Odds Ratio (CI 95%)
Long Medium Short

25. Issues to Consider When Deciding on a Telomere Test
• Reliability – Is the test accurate?
• Does the test provide both average and percent of shortest
telomeres? Average telomere length may be less useful since a
single critically short telomere may be sufficient to initiate cell
senescence (and disease onset).
• Is there a detailed questionnaire about lifestyle and health issues
including family history, so longitudinal studies are more
meaningful?

26. 2009 Nobel Prize Winner for the Discovery of Telomerase:
Dr. Carol Greider

27. Telomeres, Lifestyle, Cancer and Aging
• There is clear evidence that lifestyle factors affect the health and
lifespan of an individual by affecting telomere length.
• Shorter telomeres have been associated with increased incidence
of diseases and poor survival and increased risk of CVD.
• The rate of telomere shortening can be either increased or
decreased by specific lifestyle factors.
• Better choice of diet/nutrition, exercise and other activities has the
potential to reduce the rate of telomere shortening, leading to
delayed onset of age-associated diseases.

28. Dean Ornish Study: 5-year Lifestyle Changes Correlate
with Small Increases in Telomere Length
Control group Lifestyle intervention group
Healthy diet
Physical activity
Stress management
Social support
0.08
0.06
0.04
0.02
0
-0.02
-0.04
Mean change in telomere length (T/S)
p = 0.004 (two-tailed)
Source: Dean Ornish ….& Elizabeth Blackburn, Lancet Oncology 14:1112-1120, 2013

29. Clinical Use of Telomere Measurements
• There are many genetic and age-associated diseases that correlate
with short telomeres. Telomere testing is a powerful biomarker that
is rapidly becoming an important additional test for practicing
physicians that has clinical utility for your patients.
• Since telomere length is an independent prognostic risk factor for
cardiovascular disease, cardiologists should consider adding
telomere testing to enhance early diagnostics for CVD.
• Telomere length may be an indicator of risk for cardiovascular
diseases even before traditional biomarkers (such as cholesterol
testing) are apparent. Therefore incorporating telomere testing can
afford cardiologists opportunities for earlier interventions.

30. We are not getting older, only telomerically challenged!