Cell aging as a unique biomarker of major depression
The present invention provides methods of determining whether a subject is a suitable candidate for an anti-depressant treatment to alleviate a mood disorder by measuring telomere length and telomerase activity. The present invention also provides methods of assessing the efficacy of an anti-depressant treatment to alleviate a mood disorder and of predicting whether a subject is at risk of developing depression.
1. A method of detecting a ratio of telomere length to telomerase activity in a subject, the method comprising the steps of:
(a) obtaining from the subject a sample comprising peripheral blood mononuclear cells or leukocytes, wherein the subject is an individual who has been clinically diagnosed with Major Depressive Disorder,
(b) detecting a ratio of telomere length to telomerase activity in the sample from the subject that is higher than a ratio of telomere length to telomerase activity detected for a healthy control subject, wherein the detecting comprises measuring telomere length and telomerase activity and wherein the measuring comprises:
(i) quantifying telomere length by quantitative PCR; and
(ii) quantifying telomerase activity by telomeric repeat amplification protocol (TRAP) visualized by gel electrophoresis and phosphorimager detection; and
(c) administering an anti-depressant treatment to the subject, wherein the anti-depressant treatment is anti-depressant medication.
2. The method of any of claims 1 , wherein the anti-depressant treatment comprises administering anti-depressant medication for at least 8 weeks.
3. The method of claim 1 , comprising detecting an amount of telomerase activity in the sample from the subject that is lower than 9.5 units/10,000 cells.
4. The method of claim 1 , wherein the anti-depressant medication is a selective serotonin reuptake inhibitor.
5. The method of claim 1 , wherein the sample comprises peripheral blood mononuclear cells.
6. The method of claim 1 , wherein the sample comprises leukocytes.
7. The method of claim 1 , wherein the subject is clinically diagnosed with Major Depressive Disorder using a Structural Clinical Interview for DSM-IV(SCID).