A broad swathe of modern medical research is aimed at greater and more precise control over regeneration and growth. With the aid of technology, a body is capable of a great deal more regeneration than is naturally the case - latent capabilities lurk in the system, left over from the task of growing that body in the first place. Cancer, after all, is no more than uncontrolled growth as the result of damage in regulatory biomechanisms. It is also a demonstration of the capacity for growth and repair that will be turned to good use as scientists develop the understanding and tools needed for the job.
Regeneration of bulk parts and replacement of damaged tissue is not rejuvenation, but it should lead to a fair degree of healthy life extension. If life extension of 10 to 20 years is plausible from a simple extrapolation of systems biology, then a far better control over regeneration should add to that. It certainly won't hurt our prospects.
Here's an example of early use of techniques for nerve regrowth that will grow in sophistication in the years ahead:
Researchers at the University of California, Berkeley have developed a technology that has the potential to serve as a better alternative than currently available synthetic nerve grafts. The graft material is composed entirely of aligned nanoscale polymer fibers. These polymer fibers act as physical guides for regenerating nerve fibers. They have also developed a way to make these aligned nanofibers bioactive by attaching various biochemicals directly onto the surfaces of the nanofibers. Thus, the bioactive aligned nanofiber technology mimics the nerve autograft by providing both physical and biochemical cues to enhance and direct nerve growth.
This technology has been tested by culturing rat nerve tissue ex vivo on our bioactive aligned nanofiber scaffolds. When the nerve tissue was cultured on unaligned nanofibers there was no nerve fiber growth onto the scaffolds. However, on aligned nanofiber scaffolds, they not only observed nerve fibers growing from the tissue but the nerve fibers were aligned in the same orientation as the nanofibers. Furthermore, when there were biochemicals present on the nanofibers, the nerve fiber growth was enhanced 5 fold. In a matter of just 5 days, nerve fibers had extended 4 millimeters from the nerve tissue in a bipolar fashion on the bioactive aligned nanofiber scaffolds. Thus, this technology can induce, enhance and direct nerve fiber regeneration in a straight and organized manner.
The use of biodegradable guide materials in conjunction with signaling chemicals is in the very first stages today, but I'm sure you can see just how sophisticated this could quickly become. For example, the growth of entire organs or complex tissue can be envisaged: researchers a decade from now will use rapid prototyping technologies to build three-dimensional guide material frameworks, layered with chemicals known to produce the right growth and cellular differentiation characteristics, and add stem cells to get the job started. These initiatives and technologies exist today at varying stages of progress and sophistication; the path to this future is a straightfoward matter of development and already planned.