Pretty much every body parts get old as we age. What about blood? Can one tell if a blood sample is from a teenager or from an old person? My assumption is that no, because it gets rejuvenated constantly. I also read about an elderly Australian who has given blood 950 times because his type is so rare and the government even insured him for 1 million bucks. So if his blood is still good for saving babies....
Well just look at the case of Demi-Lee Brennan, who changed blood type after liver transplant to that of a donor. Elderly tend to have high blood pressure, so that is associated with diff. metabolic processes. The clotting process of the blood is also lower than in a younger person. Some different bio-reactive substances would be an elderly person that that of a younger one.
Well, in crime scenes when there is blood left behind they never guess the criminals age, so I must assume the difference must be very small or unmeasurable...
depends, there is definitly differences in the white blood cells. for instance there will be alot more helper t cells for different diseases as you get older because your exposed to more pathogens. as for red blood cells its possable but unlikly, there will be copy errors in the DNA but red blood cells dont HAVE DNA, or nucleouses. so the errors would have to have been translated into the other organells
The cells in the human blood do indeed age and die. Red blood cells have a lifespan of about three months. But as you point out, those dying cells are replaced by new cells. So I doubt you could tell the age of an actual individual from a blood sample.
As blood is manufactured in bone marrow, and bone marrow ages, the blood manufactured late in life may not be of the same quality as that made by a younger factory.
That sounds plausible. I just found an article which suggests that neutrophils have reduced function in the elderly (D. Biasi, A. Carletto, C. Dell'agnola, P. Caramaschi, F. Montesanti, G. Zavateri, S. Zeminian, P. Bellavite and L. M. Bambara, Neutrophil migration, oxidative metabolism, and adhesion in elderly and young subjects) I'd post the URL, but I don't have a high enough post count to do so.
Yes, like all of your other body tissues, blood changes as you age. Unless you exercise a lot, the telemeres (little end clip thingies on your chromosomes) get shorter as you age. Your blood sugar and creatine levels go up as do things like Prostate Specific Antigens. Those are not the only chemical changes that occur as you age. There will likely be medicinal chemicals present in an older persons blood as well - stuff like angiotension receptor blockers (a type of high blood pressure medication), aspirin, blood thinners and the like. The problem is that one would need a bit of blood to run the tests on, not just a trace, and each test would cost money. After all of that, you would likely be able to say something like "This persons blood has this and such in it and is lacking this and such so they are most likely to be 'older' or in poor health.' Not as conclusive as one might hope for, despite the presence of evidence of aging. This is why the coroners office gives a range of results (like "between 10 PM and 3 AM" rather than just saying "at 11:22PM").
