ⓘ François Schachter is a scientist and initiator of the Chronos project on the genetics of aging at the Centre dEtude du Polymorphisme Humain. ..

                                     

ⓘ François Schachter

François Schachter is a scientist and initiator of the Chronos project on the genetics of aging at the Centre dEtude du Polymorphisme Humain.

                                     

1. Chronos Project

In the 1990s, Schachter founded the Chronos Project. It was the first genetic survey of centenarians in the world, and Schachter confirmed that s blood was taken and her DNA extracted. This study presents the largest sample of longevity individuals ever genotyped for HLA-DR alleles, totaling 533 centenarians and 229 nonagenarians. The sample of centenarians was mainly composed of females, its male to female ratio of 1:8.

                                     

2. Research

In 1994, Schachter reported that certain specific forms of the gene apolipoprotein E were found among a group of centenarians in different quantities than in the average population.

Apolipoprotein E is a compound that plays a number of roles. It coats certain fats, that contain lipids and cholesterol, to facilitate transport from the liver to their destination organs, were apolipoprotein E facilitates the distribution, penetration and metabolism of the fats by the cells.

Inside certain cells, apolipoprotein E may also be involved in the evolution of cell morphology by shaping the cell wall composed of lipid derivatives. This aspect may be particularly important in the nervous system, where it may play a role in neuron repair and regeneration after a lesion.

Apolipoprotein E allele 4 is particularly underrepresented in centenarians, whereas allele 2 is twice as common compared to the general population. Allele 4 could adjust the risk factor for certain cardiovascular diseases, such as atherosclerosis and Alzheimers disease. These two diseases represent the major causes of death in older subjects.

The over-representation of allele 2 in centernarians indicates that this may confer protection to individuals who carry it. Exactly how this protective effect is obtained has yet to be determined.

Three individual alleles were mostly responsible for these differences: DR7, DR11 and DR13. Multivariate logistic analyses were performed in order to sort out interactions between gender-and age-specific genetic effects. DR7 frequency was elevated in longevous men, in centenarians as well as nonagenarian siblings. DR11s influence on longevity displayed a significant interaction with sex, with an increase in women from longevous sibships. DR13s frequency was increased in centenarians of both genders.