Molecular control of healing process

As seen above, healing involves an orderly sequence of events which includes regeneration and migration of specialized cells, angiogenesis, proliferation of fibroblasts and related cells, matrix protein synthesis and finally cessation of these processes.

These processes, at least in part, are mediated by a series of low molecular weight polypeptides referred to as growth factors. These growth factors have the capacity to stimulate cell division and proliferation. Some of the factors, known to play a role in the healing process, are briefly discussed below.

Sources of Growth Factors:

Following injury, growth factors may be derived from a number of sources such as:

 1.  Platelets, activated after endothelial damage,

2.   Damaged epithelial cells,

3.  Circulating serum growth factors,

4. Macrophages, or 

5.  Lymphocytes recruited to the area of injury

The healing process ceases when lost tissue has been replaced. The mechanisms regulating this process are not fully understood. TGF-β acts as a growth inhibitor for both epithelial and endothelial cells and regulates their regeneration.

The summary of molecular control of the healing process is illustrated with the diagram shown below. 

Fig. Diagram showing sources of growth factors and their effect.

References

Bezabeh ,M. ; Tesfaye,A.; Ergicho, B.; Erke, M.; Mengistu, S. and Bedane,A.; Desta, A.(2004). General Pathology. Jimma University, Gondar University Haramaya University, Dedub University.