https://commons.wikimedia.org/w/index.php?curid=75190
Volgens een recent verschenen studie van Unger (CDC) zijn de lengte van de telomeren
van patiënten met "CVS" en chronische vermoeidheid korter dan die van gezonde proefpersonen.
Toelichting:
Telomeren zijn repeterende stukjes DNA die belangrijke genen beschermen tegen het
korter worden van de chromosomen. Tijdens de celdeling wordt het DNA via replicatie verdubbeld.
Het enzym DNA-polymerase kan echter het eind van het chromosoom niet repliceren, omdat
het voortijdig van het DNA afvalt. Hierdoor worden bij elke celdeling de chromosomen iets korter.
Als het DNA te veel beschadigd is en niet meer hersteld kan worden, stopt de cel met delen of gaat dood. Als het
telomeer 4 kilobasen kort is geworden, ziet het DNA-herstelmechanisme het eind
van het chromosoom als een gebroken chromosoom waardoor de cel stopt met delen of dood gaat.
De lengte van de telomeren worden met het ouder worden steeds iets minder, maar
de telomeerlengte wordt tevens beïnvloed door oxidatie/nitrosative stress en inflammatie.
Telomere length analysis in chronic fatigue syndrome.
The FASEB Journal. 2016 Apr; 30(Suppement 1): lb459.
Unger ER, Murray J, Oakley LP, Lin JM, Rajeevan MS.
Abstract
Background
Chronic fatigue syndrome (CFS)
is a severely disabling condition associated with multi-system symptoms
including marked post-exertional malaise, fatigue, pain, unrefreshing sleep and cognitive impairment.
The symptoms and risk factors share features with accelerating aging.
Aging and
a variety of metabolic, inflammatory, infectious and neoplastic conditions
have been associated with accelerated telomere attrition.
This analysis was performed to evaluate whether CFS shares this association.
Methods
DNA was isolated from 705 PAXgene whole blood samples
from 751 participants
in the 2007-09 follow-up of the Georgia CFS Surveillance study
who completed the clinical evaluation
used to identify exclusionary medical and psychiatric conditions
that could explain fatigue.
Using the 1994 CFS Research Case Definition
with questionnaire-based subscale thresholds for
fatigue, function and symptoms,
participants were classified as:
- CFS
if all criteria met (n=71);
- CFS-X
if CFS with exclusionary conditions (n=78);
- Insufficient Symptoms/Fatigue (ISF)
if only some criteria met, regardless of exclusionary conditions (n=340);
- Non-Fatigued (NF)
if no criteria met and no exclusionary conditions (n=212);
47 NF participants with exclusions were not included and 3 could not be classified).
Relative telomere length was measured using real-time PCR.
Telomere specific primers generate a signal
proportional to total sum of the length of all telomeres in the sample (T).
Telomere signal is normalized to signal from primers to single-copy gene (S).
The T/S ratio is proportional to average telomere length per cell.
T/S is expressed relative to reference DNA, assigned T/S of 1.0.
Conversion of T/S to Southern blot hybridization determination of
terminal restriction fragment telomere length in base pairs (bp)
was based on data from 20 healthy volunteers tested by both methods.
Linear and logistic models were used
to examine association between CFS, T/S ratio and covariates.
Level of significance was set at p < 0.05.
This analysis concerned 639 participants with telomere, classification and co-variate data:
77 CFS-X, 64 CFS, 302 ISF, and 196 NF.
Results
Age (48.04 ± 0.38 years) did not differ across groups,
but obesity, sex, race, education and income, significantly differed.
T/S ratios ranged from 0.269 to 4.138.
When comparing T/S ratios across groups,
telomere lengths were significantly shorter in CFS and ISF than NF
(CFS: 0.93±0.03, ISF: 0.94±0.02; NF: 1.09±0.04).
These differences remained significant
after adjusting for covariates (age, BMI, waist-hip-ratio, education, and sex).
Based on adjusted group means,
telomere length was shorter by 212, 593 and 508 bp in CFS-X, CFS and ISF compared to NF.
As expected there was
a significant negative correlation between telomere length and age in the study sample overall.
NF subjects started with long telomeres but shortened at a faster rate (59 bp/year)
than the rate of telomere shortening in CFS-X (25.4 bp/year), CFS (21.2 bp/year) and ISF (4.2 bp/year).
Conclusions
Our results indicate that
CFS should be included in the list of conditions associated with telomere shortening.
Further work is needed to evaluate if the shortening has functional significance in CFS.
Footnotes
This abstract is from the Experimental Biology 2016 Meeting.
There is no full text article associated with this abstract published in The FASEB Journal.
http://www.fasebj.org/content/30/1_Supplement/lb459.abstract
Met dank een Manja, die het internet beter inde gaten houdt dan ik.
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