The ability of cells to divide and multiply is essential to life, allowing complex organisms to form from a single cell, while also allowing a limited number of stem cells to replace those already used, and subsequently multiply and specialize. In cancer, however, cell proliferation is no longer controlled and becomes disorganized.
The formation of complex multicellular organisms to which humans belong requires the generation of billions of cells from a limited number of progenitor cells, which first proliferate and then acquire characteristic forms and functions in the process of assembling into tissues and organs. The consensus of research states that most of the cells that make up an organism originate from so-called stem cells, which are able to divide and produce more cells through a process called mitosis. Then these cells will stop proliferating, and start to specialize, differentiate and form muscle, brain, bone, immune cells, etc. When the proliferation process can no longer be properly regulated, it will lead to the occurrence of various diseases in the body, among which cancer is very representative example.
The researchers found that this ability to proliferate is not limited to stem cells, but is also a poorly understood function of the immune cells in the blood, monocytes, which, indeed, were previously thought to be differentiated cells. It proliferates and creates a pool of monocytes in tissues that further develop into macrophages, important immune cells that protect the body against microorganisms and support the normal functioning of the body's organs.
The researchers believe this could be a major discovery that could change the notion that cell proliferation is involved in building and maintaining the body's immune system. The findings also suggest that important information may be gleaned from blood monocyte counts, which are classically counted during blood tests and reflect only a small number of conditions that occur at the tissue level, such as during infection or inflammation, Because monocytes are able to proliferate when they enter tissues. Fortunately, however, this proliferation process is so well controlled that it does not lead to tumorigenesis and has only one goal, which is to remove as efficiently as possible the immune cells that populate the body's tissues—macrophages.
This discovery was made possible thanks to the development of new tools and the innovative techniques used by the researchers. It was quite difficult for scientists to study proliferating monocytes at this resolution just 10 years ago. This requires the use of advanced equipment developed by researchers and the generation of complex genomic data and bioinformatics analysis data. The study opens up the possibility for later scientists to further investigate and evaluate the possibility of manipulating or controlling the proliferation of monocytes for therapeutic purposes, which may be beneficial to enhance the body's health.
This study presents correlative evidence that in the mononuclear phagocyte system, its proliferative capacity is not restricted to bone marrow histiocytes and mature resident tissue macrophages, but also a tightly regulated capacity possessed by monocytes that develop into resident tissue macrophages in vivo.