The impact of aging on memory T cell phenotype and function in the human bone marrow.

Recently, the BM has been shown to play a key role in regulating the survival and function of memory T cells. However, the impact of aging on these processes has not yet been studied. We demonstrate that the number of CD4⁺ and CD8⁺ T cells in the BM is maintained during aging.

GiSAO.db: a database for ageing research.

Background: Age-related gene expression patterns of Homo sapiens as well as of model organisms such as Mus musculus, Saccharomyces cerevisiae, Caenorhabditis elegans and Drosophila melanogaster are a basis for understanding the genetic mechanisms of ageing. For an effective analysis and interpretation of expression profiles it is necessary to store and manage huge amounts of data in an organized way, so that these data can be accessed and processed easily.

Description: GiSAO.

Age-specific changes of mesenchymal stem cells are paralleled by upregulation of CD106 expression as a response to an inflammatory environment.

Regeneration, tissue remodeling, and organ repair after injury, which rely on the regulated activity of tissue-borne stem cells, become increasingly compromised with advancing age. Mesenchymal stroma cells were isolated from bone of differently aged healthy donors. The rare population of mesenchymal stem cells (MSCs) contained in the primary cell isolates barely declined in number, yet the stem cells displayed diminished long-term proliferation potential relative to the donor age and the expression of vascular cell adhesion molecule-1 (VCAM-1; CD106) was elevated on primary MSCs.

Non-regulatory CD8+CD45RO+CD25+ T-lymphocytes may compensate for the loss of antigen-inexperienced CD8+CD45RA+ T-cells in old age.

The age-related decline in immune system functions is responsible for the increased prevalence of infectious diseases and the low efficacy of vaccination in elderly individuals. In particular, the number of peripheral naive T-cells declines throughout life and they exhibit severe functional defects at advanced age. However, we have recently identified a non-regulatory CD8+CD45RO+ CD25+ T-cell subset that occurs in a subgroup of healthy elderly individuals, who still exhibit an intact humoral immune response following influenza vaccination.

Microarray analysis reveals similarity between CD8+CD28- T cells from young and elderly persons, but not of CD8+CD28+ T cells.

We isolated highly purified CD8+CD28+ and CD8+CD28- T cell populations from healthy young and elderly persons for gene expression profiling using Affymetrix oligonucleotide microarrays. We demonstrate that the gene expression profile of CD8+CD28- T cells is very similar in young and elderly persons. In contrast, CD8+CD28+ in elderly differ from CD8+CD28+ in young persons.

Leptin receptor/CD295 is upregulated on primary human mesenchymal stem cells of advancing biological age and distinctly marks the subpopulation of dying cells.

During the lifetime of an adult organism, stem cells face extrinsic and intrinsic aging. Mesenchymal stem cells (MSC) can be expanded in culture, and the proliferation potential of individual cell isolates before growing senescent appear to be dependent on fitness and age of the donor, respectively. To date no molecular markers are available, which specifically reflect the degree of cellular aging in a population of MSC.

Changes of the Functional Capacity of Mesenchymal Stem Cells due to Aging or Age-Associated Disease - Implications for Clinical Applications and Donor Recruitment.

SUMMARY: In contrast to stem cells of embryonic origin, autologous tissue-specific stem cells are easier to introduce into the clinical practice. In this context, molecular and cellular changes, which alter tissue-specific stem cell properties with age, are of particular interest since elderly patients represent the main target group for cell-based therapies. The clinical use of mesenchymal stem cells is an emerging field, especially because this stem cell type appears to be amenable for the treatment of a large number of diseases, such as non-healing bone defects and fractures, inflammatory relief during arthritis, and the repair of suspensory ligament tears.

Mouse testicular hyaluronidase-like proteins SPAM1 and HYAL5 but not HYALP1 degrade hyaluronan.

Besides SPAM1 (sperm adhesion molecule 1; formerly named PH-20), further hyaluronidase-like proteins, HYAL5 (hyaluronoglucosaminidase 5) and HYALP1 (hyaluronoglucosaminidase pseudogene 1) are also expressed in murine testicular tissue. As they share a high degree of sequence similarity with known hyaluronidases, all three polypeptides could potentially exhibit hyaluronidase activity, a function that is beneficial for spermatozoa in order to penetrate the hyaluronan-rich cumulus, which surrounds the oocyte. Recently, it was reported that SPAM1-deficient mice are fertile and spermatozoa derived from mutant mice still exhibit hyaluronidase activity [Baba, Kashiwabara, Honda, Yamagata, Wu, Ikawa, Okabe and Baba (2002) J.