Background: Longevity refers to the length of time an organism lives and is characterized by progressive decline in tissue and organ function and increased risk of mortality and is also often associated with a healthy and fulfilling life. Cellular health as one prerequiste for longevity is controlled by a number of regulatory pathways which coordinate the various processes of cell aging. L.I.F.E. technology was created to promote the replicative lifespan, measured by the number of mitotic divisions until replicative senescence occurs and was studied with primary cultured eucaryotic cells of the respiratory tract possessing a limited lifespan.

Experimental: Primary respiratory epithelial cells of fourth passage were seeded at extremely low density (20,000 cells/75 cm2 flasks in 20 ml culture medium). This was the first passage (P1) of the subsequent longevity experiments with and without L.I.F.E. technology. The circular object with L.I.F.E. technology was always placed directly beneath the cell culture flasks. Cells were cultivated in two separated mini-incubators at 37°. At definite time points cells were subcultured by trypsin/EDTA treatment and seeded at the same initial densities in new cell culture flasks with fresh culture medium. This procedure was done four times (P1 ð P4) until the cells reached replicative senescence and remained in a post-mitotic state. At each time point the cell densities in the flasks were examined by using a specialized software. The total incubation time of the cell cultures with and without L.I.F.E. technology was 28 days representing about 25-30 mitotic cell divisions which are equivalent to a period of at least several months in vivo.

Results: During the experimental cultivation period of the cells from P1 ð P4, their mitotic activity decreased with the numbers of subcultures/in vitro-age. However, this natural senescence of primary cells was much lower in all passages for cell cultures which were exposed to L.I.F.E technology compared to untreated cell cultures. After only 6 days of cultivation, the increase in mitotic cell divisions by L.I.F.E technology was moderate with about 20%, but was more than 150% after 28 days. The difference between both cell cultures, with and without L.I.F.E. technology, was always statistically significant (p ? 0.01; two-tailed Wilcoxon-Mann-Whitney rank-sum test).

Conclusions: As shown in this study with primary respiratory cells, one of the main paradigms of longevity, namely the promotion of a prolonged ageing process, is the positive effect of the application of L.I.F.E. technology on cellular level. Moreover, the quality of life associated with improved individual systemic health by L.I.F.E. technology might be also effective for the whole human body.