Only 7 Pathogenic Age-related Precursors: Toxic Cells

One of the seven early precursors of age-related pathology are cells that are harmful but which sidestep the body's mechanisms to eliminate them.

There are three such kinds of cells that are targeted by SENS research:

visceral fat cells (with its relation to diabetes);
senescent cells (unreplicative cells, many of which spew toxins); and,
certain kinds of immune cells (which crowd out more functional immune cells).

Visceral Fat Cells

Visceral fat (located in the abdomen) releases hormones that interfere with insulin signalling, contributing to insulin resistence and therefore type 2 diabetes.

Senescent Cells

Senescent cells are cells that exhibit enough evidence of chromosomal damage to trigger an adaptive mechanism that shuts down replication. This is believed to be an adaptive feature to prevent highly mutant cells from becoming cancerous. For example, short telomeres (evidence of great cell age) and irradiation can trigger senescence in vitro.

Senescent cells are found in vivo, mostly concentrated in articular (joint) cartilage, and seems to be a result of chromosomal breakage.

Despite their inability to divide (and thus become cancerous), they are characterized by excessive secretion of tumorigenic proteins. (Without being cancerous, tumoric growth risks cancer, since rapid cell division can prevent pre-cancerous mutations from being repaired before cell division makes them permanent.)

Certain Kinds of Immune Cells

Of especial interest are T cells whose cognate antigens are herpesviruses and cytomegalovirus (CMV). The immune system never fully gets rid of them, thus cognate T cells are produced throughout life. They crowd other immune cells, suppressing the whole immune system, and, worse, don't seem to work very well.

Getting Rid of Toxic Cells

Proposed strategies for killing these cells would

take advantage of cell surface markers, or
identify senescent cells by the outpouring of certain proteins

to focus treatment and minimize side effects.

The two proposed strategies are

inducing apoptosis (cell suicide), and,
stimulating the immune system to kill the cell.

Note that we don't discuss mutant mitochondrial cells on this page, partly because they wouldn't be identified by surface markers and partly because of the context needed to understand their special situation. Proposed strategies to eliminate them, while allotopic expression is being developed, are to temporarily suspend one of a few mitochondrial processes that wild-type (normal) cells would survive and mutant mitochondrial cells can't. More about such strategies can be found here.

Though surgery is a possible solution for visceral fat removal, it is quite invasive. Liposuction removes subcutaneous fat, while visceral fat is much deeper, coating the major abdominal organs. Such surgery may be unnecessarily invasive if surface markers can be taken advantage of. High doses of leptin have been shown to shut off visceral adipocytes' production of the pathogenic hormones. Meanwhile a good diet and exercise help too.