The role of skin cells, what can affect thier growth and production for example calcium or vitamin D and what can occur if that production becomes abnormal.
The skin has multiple layers, and the body constantly replenishes cells that naturally work their way up through those layers and eventually fall off.
The goal of this endless skin cell production is to replace the epidermis, the outer skin layer, which turns over about every one to two months. The epidermis is made of many layers and the deepest layers are the cells that are continuously growing, dividing and making new cells.
Cells move upward through the layers reaching toward the surface, maturing as they go. Ultimately the skin provides a mechanical barrier to shield the body from micro organisms and other invaders, such as water when showering or swimming. Conversely it also helps keep water that’s inside the body where it belongs.
To get the job done, dynamic skin cells, called keratinocytes, must know how to make keratin, which is like a steel cable going through the cells. They must also make structural proteins and enzymes that keep the skin from dissolving in detergents and fats to help with water impermeability.
Once they work their way to the top, the cells’ final job is to die. But in the common painful, disfiguring disease psoriasis as well as non-melanoma skin cancers, some cells never get the signal to die; instead they continue to proliferate, resulting in abnormal tissue growth. Joint or Inflamotory diseases occur whenthe cells in connective tissues get too many signals to die, so the cells are degraded faster then they are synthesized.
Researchers know that calcium, vitamin D and parathyroid hormones, which respond to calcium and vice versa, come into play in most tissues and more recently have determined they have roles as well in the normal maturation and production of skin cells.
For example, vitamin D seems to influence maturation by influencing signals within skin cells. Vitamin D increases the expression and activity of phospholipase D, one of the signalling enzymes that tells skin cells where they need to be in the maturation process. The expression of phospholipase D in turn activates other signals which influence expression of substances involved in cell structure and development For many years, it has been clear that putative stem cells (cells that can divide to replenish themselves and, as well, produce daughter cells that transition into differentiated cell types) exist in a number of adult tissues, including bone marrow, muscle, and intestine. Bone marrow cells have been used to replace the hematopoietic and immune systems in therapies for diseases.
In tissue turnover there needs to be a balance between synthesis and degredation of cells for normal processes to occur otherwise you get conditions like psoriasis or inflamatory diseases to name a few.
