The process of aging is an inexorable and manifest fact of existence. We age, we know it, and we observe it in all of those around us.
It is only recently, however, that the subject of Aging has begun to attract serious scientific and medical inquiry; the reasons for this are manifold. The subject of aging, and its serious study, has been irreparably damaged by centuries of snake-oil salesmen peddling various concoctions for increasing life span (this in itself is perhaps an interesting subject for a retrospective review). The inquiry into the biological basis of Aging has been further confounded by the heterogeneity and complexity of the aging process.
The 'science' and study of Aging has, however, in the last twenty-five years moved from the periphery of formal inquiry to an emerging framework that seeks a place at the centre of biological and medical science. Two important topics in this issue, the aging of the hematopoietic system and cancer are critically elucidated in reference to this framework.
The cover article in this issue is on the aging of the haematopoietic system. This article is a continuation of a series of articles on age-related changes in various organ and physiological systems. All the principal organ systems will be covered in this series and it should serve as an excellent reference for the future. Great attention has been devoted to visually articulating the subject matter. Age-associated decline occurs in all the systems of the body, although some systems are more affected than others. The digestive system, which was dealt with in the last issue, is minimally affected. The hematopoietic system, vital to overall function, is characterized in the elderly by increased marrow fat, decreased blood flow, and decreased ability of hematopoietic stem cells to regenerate. All of these changes lead to decreased hematopoiesis. The recently discovered process for cloning embryonic stem cells and T-cell precursors might provide critical insights and potential tools for regenerating the hemato-poietic system or, even better, preventing its decline.
The focus section in this issue is devoted to the subject of cancer in the elderly. Cancer is very much a disease related to the aging process. As the report of the Canadian Cancer Society states, cancer is primarily a disease of older Canadians, with 70% of new cancer cases and 82% of deaths due to cancer occuring among those who are at least sixty years old. With the increasing number of elderly Canadians, much of the burden of cancer diagnosis falls on the primary care doctor.
Progress in Cancer therapy has been very slow. As Jerome Groopman of Harvard has suggested, it has been based "on serendipity and trial and error more than on any sort of deep knowledge of malignancy or any sort of rational approach to its conquest". Slowly however, the black box of the cancer cell is yielding its secret, and in yielding its secrets, it is revealing some of the genetic mysteries that underlie the aging process itself.
Breakthroughs in understanding cancer may yield fundamental insights into the aging process. This past summer, Robert Weinberg and his team at MIT's Whitehead Institute, published a paper that reveals the process that turns a normal cell cancerous. Only three genes were necessary. Telomerase, an enzyme that regulates telomere length was a key element of this experiment. The result is of seminal significance for the understanding of both the genetics of cancer and the aging process itself. Gradually, the genetics underlying cancer will be teased apart. Diagnostic tests should follow. The elderly, who suffer disproportionately from cancer should be the biggest beneficiary of this process.
'Aging', as a multifarious and complex process--occurring at the genetic and the physi-ological levels, and affecting the individual as a whole--is the overarching scientific metaphor for Geriatrics & Aging. It is a metaphor that provides a point of convergence for disparate scientific, medical and clinical information. It serves as the thematic backdrop and guiding vision, for a publication that is directed at the practical, clinical decision-making needs of the primary care physician. This organizing vision lends coherence to the publication as a whole.
As I close this issue, I would like to reach out to the readers of Geriatrics & Aging and to ask you how we could improve the publication, and how we could make the publication more relevant to you.
Please e-mail me at geriatrics@ribosome.com.
