idw – Informationsdienst Wissenschaft
Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
A team of collaborating researchers from the Swedish universities of Umeå, Stockholm, and Linköping is now publishing data showing that long telomeres in non-demented adults and seniors can be associated with poorer memory.
The end portions of chromosomes, telomeres, are important in protecting the genes inside. Every time a cell divides, these telomeres become shorter. After multiple cell divisions, the telomeres become so short that the cell either self-dies or wind up in an aged, resting stage. Measurement of telomere lengths therefore provides information about how many times the cells has divided in the past.
This new study is part of the major Betula Project, which, according to the Swedish Research Council, is one of the ten strongest research settings in Sweden and has the goal of studying how the memory changes during aging. It comprises 427 non-demented individuals between the ages of 41 and 81 years. The scientists studied whether individuals with different forms of apolipoprotein E (APOE) have different telomere lengths in their blood cells and whether variations in telomere length is linked to memory capacity, assessed with the help of memory tests. Previous research has described the connection between the form of APOE 4 and cardiovascular disease and dementia. It has also been shown that this variant increases the risk of a type of memory degradation that is most pronounced in older individuals without dementia. This is a degradation of memory in the so-called episodic memory system, which, in simple terms, has the assignment of remembering episodes in life.
In summary the newly published study shows that individuals with APOE 4 have longer telomeres than those with other APOE variants. It was also found that the difference in telomere length between APOE 4 and other APOE variants increased the younger the individuals compared were. In the group that had the variant APOE 4 the individuals with the longest telomeres performed less well on episodic memory tests but not on other tests.
The APOE protein plays a central role in transporting and metabolizing blood fats, but the various forms also appear to have different effects on other processes in the body. The 4 variant is linked with worse blood fats, more inflammation, and increased oxidative stress compared with the 2 and 3 variants. It has previously been shown that both inflammation and oxidative stress lead to shorter telomere length. It was therefore surprising that individuals with the 4 variant had longer telomeres than individuals with the other APOE forms. The longer telomeres support the notion that the cells have undergone a lower number of cell divisions and that the differences in length arose at some time prior to the lower age limit for the study. Such reduced cell division early in life may be an explanation for the worse episodic memory of people with the 4 variant compared with that of individuals with other variants. More studies are needed to confirm these findings and to determine through what mechanisms long telomeres are associated with poorer episodic memory and with any other possible APOE 4-associated processes in the body.
The researchers behind the study are Karl-Fredrik Norrback, Rolf Adolfsson, Göran Roos, and Lars Nyberg at Umeå University; Lars-Göran Nilsson, Stockholm University; and Thomas Karlsson, Linköping University, as well as doctoral candidate Mikael Wikgren. The project coordinator Annelie Nordin has also been important for the conducting of the study.
For more information, please contact: Karl-Fredrik Norrback, MD, PhD, Dept. of Clinical Science, Division of Psychiatry, Umeå University, Mobile phone: +46 (0)70-441 5904, e-mail: karl-fredrik.norrback@psychiat.umu.se
Pressofficer Hans Fällman; hans.fallman@adm.umu.se; +46-70 691 28 29
Reference: Wikgren M, Karlsson T, Nilbrink T, Nordfjäll K, Hultdin J, Sleegers K, Van Broeckhoven C, Nyberg L, Roos G, Nilsson LG, Adolfsson R, Norrback KF APOE epsilon4 is associated with longer telomeres, and longer telomeres among epsilon4 carriers predicts worse episodic memory, Neurobiology of Aging, 2010 Apr 13 (10.1016/j.neurobiolaging.2010.03.004).
New text:
The end portions of chromosomes, telomeres, are important in protecting the genes inside. Every time a cell divides, these telomeres become shorter. After multiple cell divisions, the telomeres become so short that the cell either self-dies (undergoes apoptosis) or wind up in an aged, resting stage called senescence. Measurement of telomere lengths therefore provides information about how many times the cells have divided in the past.
This new study is part of the major Betula Project, which, according to the Swedish Research Council, is one of the ten strongest research settings in Sweden and has as one of it´s goals to study how the memory changes during aging. It comprises 427 non-demented individuals between the ages of 41 and 81 years. The scientists studied whether individuals with different forms of apolipoprotein E (APOE) have different telomere lengths in their blood cells and whether variations in telomere length is linked to memory capacity, assessed with the help of memory tests. Previous research has described the connection between the form of APOE ε4 and cardiovascular disease and dementia. It has also been shown that this variant increases the risk of memory dedine of a particular type that is most pronounced in older individuals without dementia. The decline in memory is observed within the episodic memory system, which, in simple terms, has the assignment of remembering episodes in life.
In summary the newly published study shows that individuals with APOE ε4 have longer telomeres than those with other APOE variants. It was also found that the difference in telomere length between APOE ε4 and other APOE variants increased the younger the individuals compared were. In the group that had the variant APOE ε4 the individuals with the longest telomeres performed worse on episodic memory tests but not on other tests.
The APOE protein plays a central role in transporting and metabolizing lipids, but the various forms also appear to have different effects on other processes in the body. The ε4 variant is linked to a worse bloodlipid profile, more inflammation, and increased oxidative stress compared with the ε2 and ε3 variants. It has previously been shown that both inflammation and oxidative stress lead to shorter telomere length. It was therefore surprising that individuals with the ε4 variant had longer telomeres than individuals with the other APOE forms. The longer telomeres supports that cells have undergone a lower number of cell divisions and that the differences in length arose at some time prior to the lower age limit for the study. Such reduced cell division early in life may be an explanation for the worse episodic memory of people with the ε4 variant compared with that of individuals with other variants. More studies are needed to confirm these findings and to determine through what mechanisms long telomeres are associated with poorer episodic memory as well as with potentially other APOE ε4-associated processes in the body.
The researchers behind the study are Karl-Fredrik Norrback, Rolf Adolfsson, Göran Roos, and Lars Nyberg at Umeå University; Lars-Göran Nilsson, Stockholm University; and Thomas Karlsson, Linköping University, as well as doctoral candidate Mikael Wikgren. The project coordinator Annelie Nordin has also been important for conducting the study.
Merkmale dieser Pressemitteilung:
Biologie, Medizin
überregional
Forschungsergebnisse
Englisch
Sie können Suchbegriffe mit und, oder und / oder nicht verknüpfen, z. B. Philo nicht logie.
Verknüpfungen können Sie mit Klammern voneinander trennen, z. B. (Philo nicht logie) oder (Psycho und logie).
Zusammenhängende Worte werden als Wortgruppe gesucht, wenn Sie sie in Anführungsstriche setzen, z. B. „Bundesrepublik Deutschland“.
Die Erweiterte Suche können Sie auch nutzen, ohne Suchbegriffe einzugeben. Sie orientiert sich dann an den Kriterien, die Sie ausgewählt haben (z. B. nach dem Land oder dem Sachgebiet).
Haben Sie in einer Kategorie kein Kriterium ausgewählt, wird die gesamte Kategorie durchsucht (z.B. alle Sachgebiete oder alle Länder).
