Accumulating Insoluble Protein and Rate of Aging

Mitochondrial translocation in young and old cells

In most cells, the mitochondria are constantly moving along microtubule chains. This paper proposes the hypothesis that the mitochondrion is directed to locations in the cytoplasm rich in nutrition (pyruvate, lipid droplets) by fluid movements within the cytosol that are induced by local differences in osmotic pressure. When the mitochondrion absorbs pyruvate and phosphate, the osmotic pressure decreases and becomes lower than in other locations. In old cells, part of the volume is excluded to the mitochondria by accumulated cross-linked proteins. When the mitochondria are fixed, as in striated muscle, the metabolic exchange may be confined to diffusion of the metabolites.

Makeham's addition to the Gompertz law re-evaluated

The Makeham parameter, a constant mortality rate independent of aging added to the Gompertz law of human mortality, is proposed to be a measure of the impact on mortality rate by extrinsic causes of mortality, with the effect of aging removed. A small intrinsic contribution to mortality, assumed to depend on the components involved in cellular function, is linked to the initial mortality rate of the Gompertz law. To avoid biased results and conclusions, the impact of extrinsic mortality should be eliminated from the Gompertz parameters.