Telomeres

Lots of interest currently into relationship of telomere length on aging – or vice versa.

Telomeres are a  region of repetitive nucleotide sequences at the end of chromosone which reduce in length over time – therefore hinting they may be involved in the aging prcess, i.e. length reduces to zero and cell blows up (I’m simplifying slightly!)

Resources

Telomere length testing kit – Titanovo
Measured in relative T/S and in absolute length in kbp (kilobasepairs)

TeloYears – finger prick blood DNA test provides your Average Telomere Length (ATL)

Latest News

Telomere loop structure more important than length – Medical Xpress – 20-Jul-2018
People born with abnormally short telomeres suffer a variety of conditions.
New research identifies why telomeres change from healthy to unhealthy with age.
Telomeres normally form a loop structure, where the chromosome end is hidden.
When loop unfolds, the chromosome end is exposed and perceived as broken DNA.
It is not telomere length that matters, but telomere structure.
New super-resolution microscopy allows loops to be seen.

Telomerase: Downgraded by long term proponent – Josh Mitteldorf Blog – 19-Mar-2018
Josh Mitteldorf curbs his enthusiasm based on latest study.
Telomerase affects epigenetics in ways that accelerate aging.
Genome-wide association study of 9907 individuals.
People with longer telomeres tend to age faster, as measured by the Horvath clock.
No Horvath aging at all in the cell cultures that lacked telomerase.

Long-Lived Bats Have Telomeres That Don’t Shorten – Inverse – 7-Feb-2018
These mouse-sized mammals live way longer than they should.
Some of the telomeres of Myotis bats do not shorten as they age.
As well as genes for telomerase, they have 21 other telomere maintenance genes.
Like humans, don’t express telomerase in their blood cells.

Telomeres Do Not Translate Into A Younger Biologic Age – Institute For Aging Research – 31-Jan-2018
TERT is a subunit of the enzyme telomerase.
DNA methylation age is a biomarker of chronological age and predicts lifespan.
TERT locus has significant associations with epigenetic aging rates.
Therapies based on telomerase expression would be accompanied by continued aging.
Institute for Aging Research analyzed blood samples from nearly 10,000 people.

Motherhood Causes 11 Years of Telomere Shortening – Science Alert – 26-Feb-2018
DNA collected from nearly 2,000 reproductive-age women.
Those who had given birth had telomeres that were 4.2 percent shorter.
Equivalent to around 11 years of accelerated cellular ageing.
Shortening varied depending on how many children the women had.

Prenatal pollution exposure linked to decreased telomere length – 2 Minute Medicine – 25-Oct-2017
Telomeres are short stretches of DNA are the ends of chromosomes and are essential for fidelity of genetic information during cell division.
Telomere length (TL) has been associated with cellular longevity and is thought to play an important role in cellular aging and senescence.
Many exposures, including pollution, may have an effect on TL.
The current study found that prenatal environmental pollution exposure was linked to decreased telomere length measured in cord blood and placental cells.

Direct correlation between telomere length and heart failure found – Medical Xpress– 7-Sep-2017
Study used human heart tissue samples from organ donors and heart transplants patients.
Measured telomere lengths in the samples from patients with and without heart disease.
In healthy people, age did not play a role in telomere length.
Patients with heart failure had shorter telomeres regardless of their age.

Josh Mitteldorf argues against long telomeres causing cancer – Josh Mitteldorf – 23-Aug-2017
Major new study argues that longer telomeres increase risk of cancer five-fold.
New study ased on genetics and account for telomere length only indirectly.
Josh argues evidence is less reliable:
1. previous studies used direct correlations
2. new studies require very large implicit 50 to 1 extrapolation
3. may actually be seeing direct effects of genetics on cancer risk

Research holds Promise for Future Clinical Therapies to Slow Aging – Next Big Future – 1-Aug-2017
Cells from children with progeria studied.
Progeria is a rare condition marked by rapid aging.
telomeres were shorter in children with progeria
Used RNA therapeutics to create telomerase that lengthens telomeres.
Single exposure had a substantial physiologically relevant and meaningful effect on the lifespan and function of the cells.
Improved ability to divide and reduced inflammatory proteins.

Scientists Discover Master Regulator of Cellular Aging – TSRI – 12-Jan-2017
Newly discovered a protein, named TZAP, binds the ends of chromosomes.
TZAP controls a process called telomere trimming, ensuring that telomeres do not become too long.
Lengthening telomeres could slow aging but unnaturally long telomeres are a risk factor in developing cancer.
This protein sets the upper limit of telomere length.

Poor Correlation Between Telomere Length and Health – Fight Aging! – 2-Sep-2016
Telomeric DNA decreases with age and when they get too short cells self-destruct or become senescent.
No association found between telomere length and current health status.
Study of 351 blood samples at age 49-51.
Variation in length is large between individuals and is fairly dynamic for any individual in response to circumstance and illness.
COMMENT: when telomere length testing is cheap enough it might still be worth monitoring long term averages in case they turn out to be important

Telomere Length Does Not Predict Atherosclerosis Risk – Fight Aging! – 25-May-2016
Epidemiological studies have demonstrated shorter leukocyte telomere length (LTL) in patients suffering coronary artery disease, heart attack or stroke.
New study suggests that LTL in circulating blood does not effectively predict CVD risk in individuals without disease symptoms.
We don’t know if atherosclerosis progresses faster in people who start with shorter leukocyte telomeres, have a higher proportion of very short telomeres, or in whom telomeres shorten at a faster rate during the aging process.
There is need to find new biomarkers to enable the early identification of individuals at high risk of developing atherosclerosis because around half of cardiovascular disease (CVD) patients do not have a high risk profile based on classical risk factors.
Study included 1459 volunteers participating in the PESA (Progression of Early Subclinical Atherosclerosis) clinical trial.

Impatient People Likely To Age Faster  – Tech Times – 24-Feb-2016
Shorter telomeres discovered in impatient subjects.
Patience of 1,158 undergraduates judged by willingness to delay cash reward.
Blood samples of participants analyzed.
More impatient people had short telomeres which is linked to aging.
Causal relationship not proven.

How Long Will You Live? – Veritasium – 25-Nov-2015
Great video introduction to one of the causes of aging – telemere length v cancer inducing telemerase.
We age at the macroscopic level because our cells are aging at a microscopic level.
Human cells Only divide a finite number of times (50 on average).
Accumulation of these senescence cells that lead to aging.

Telomeres naturally shorten each time DNA is copied in preparation for cell division – Kurzweil AI – 13-Nov-2015
Shortened telomeres have been implicated in aging and disease.
Telomerase not the full picture.
ATM kinase needed to lengthen telomeres. Also involved in DNA repair.

Telomere testing – Life Length

Alpha lipoic acid lengthens telomeres – Emory University – 20-Aug-2015
Dietary supplement alpha lipoic acid (ALA) can stimulate telomerase, the enzyme that lengthens telomeres, which could have positive effects on chronic diseases such as atherosclerosis and diabetes. ALA is present in many foods and counteracts high-fat-diet-induced, age-dependent arteriopathy.

Telomere Length and Mortality — Humanity+ – 4-May-15
Danish study of 65,000 people shows telomere length robustly predicts longevity.

Telomere extension turns back aging clock in cultured human cells – Stanford University – 22-Jan-15

Telomerase “off” switch discovered; stops cells dividing indefinitely – Salk Institute – 19-Sep-14