Performing the experiment described below will secure winning the Homeostatic Capacity half of the Prize. The probability of the proposed study to demonstrate significant improvement of the heart rate variability marker is extremely high, because parabiosis was already shown to promote functional parameters of the nervous and cardiovascular systems. Now, by using a young clone we can reduce all possible immunological adverse reactions to the minimum and see how the old animal rejuvenates because of the circulating systemic factors produced by the young clone. Check out the detailed prize-winning study description here.
Heterochronic parabiosis for old mouse rejuvenation
One of the most productive paradigms of aging suppression is based on rejuvenation of blood-borne systemic regulatory factors. Parabiosis, which is characterized by a shared blood supply between two surgically connected animals, may provide such experimental paradigm. We propose to use heterochronic parabiosis, the parabiotic pairing of two animals of different ages, for old mouse rejuvenation. Heterochronic parabiosis also provides an experimental system to identify systemic factors influencing the aging process of the old mouse and promoting its longevity. The optimal rejuvenation effect of heterochronic parabiosis can be achieved by using cloned (genetically identical) animals. This will help avoid potential side effects caused by immune response.
The early reported studies that used heterochronic parabiosis in rodent models to study lifespan regulation provided evidence of significant benefit to the older parabiont (reviewed in Conboy et al., 2013; Eggel, Wyss-Coray, 2014). Heterochronic parabiosis resulted not only in lifespan extension of the older parabiont (Ludwig & Elashoff, 1972), but it also promoted functional and regeneration potential in the aging central nervous system (Ruckh et al., 2012; Villeda et al., 2011), muscle and liver (Conboy et al., 2005), reversed age-related cardiac hypertrophy (Loffredo et al., 2013) and some other age-related parameters. Thus heterochronic parabiosis experiments indicate that blood-borne signals from a young circulation can significantly impact the function of aging tissues. The implication of these findings is that old tissues might make their function almost as well as young tissues if, by means of systemic influences, the molecular pathways could be ‘rejuvenated’ from an old state to a young state.
The optimum rejuvenation effect of heterochronic parabiosis can be achieved using genetically identical animals. Genetically identical non-model organisms of different age can only be obtained by cloning. Interestingly, that there are no investigations of heterochronic parabiosis of cloned animals.
The aim of the project is the comprehensive investigation of rejuvenation potential of cloned mice heterochronic parabiosis.
Research plan:
At first we will perform cloning of adult (1-year-old) mice using technique for improved success cloning rate (Mizutani et al., 2014).
The study is performed in five groups of animals:
- Pair of cloned young and old heterochronic parabionts.
- Pair of young and old heterochronic parabionts (not cloned).
- Pair of two young parabionts.
- Pair of two old parabionts.
- Intact control animals.
The parabiosis is established at the age of 18 months for old partners and 2 month for the young ones. The detailed life span assay reveals the influence of heterochronic parabiosis with young clone on cardiovascular, nervous, respiratory, skeletal and muscular systems. The lifespan assay shows the young clone parabiosis impact on longevity of older partner.
In addition, systemic factors, which influence the aging process of the old mouse and promote its longevity and rejuvenation, are revealed.
Expected results:
- Study of heterochronical parabiosis effects on the process of cell and tissue aging, development of age-related diseases, and other age-related parameters including organismal longevity of the old mouse
- Identification of rejuvenation factors
- Results of the experiment may be used for development of human rejuvenation approach by systemic regulation of the aging process