Macrophages and T-Lymphocytes Secrete Collagen

There are several potential sources of origin for the capsule collagen that surrounds a dormant or benign tumor that is not a pseudo-capsule generated from compression of the stromal tissues.  One overlooked source of the capsule demonstrated by Vaage in 1991 is the immune system itself, with lymphocytes and macrophages surrounding aberrant, immunogenic cells with a collagen capsule.  Research regarding the involvement of macrophages and lymphocytes in useful and pathological collagenous fibrosis is an important facet of fibrosis mechanisms that is still highly relevant today, in 2012.  Of course, any collagen synthesis requires Vitamin C/ascorbic acid/ascorbate.  Innate defense and cytotoxic immune cells in particular use vastly large quantities of it, accumulating it against an osmotic gradient to 100-fold more than the surrounding serum or plasma.

Collagen production by macrophages in tumour encapsulation and dormancy.

Fibrous Capsule of a dormant (not growing) tumor (Vaage 1991)

T-Lymphocyte Secreted Collagen Fibers, Vaage 1991

 

 

"Millions of Cracks" in Artery Wall = Leaky Junctions

In Tarbell's research, 90% of LDL, the delivery particle that solubilizes otherwise insoluble cholesterol gets through the first layer of an artery through a "leaky junction."  The normal pores in the first layer of an artery are just too small for anything other than albumin and micromolecules in water to get through.  Nothing gets through a tight junction.  Large gaps, leaky junctions, occur only when the layer of cells divides or is injured, pulling away from each other and revealing the subintimal layer.  Only 10% of LDL gets through by active vesicular consumption. 

Stretch and Shear Interactions Affect Intercellular Junction Protein Expression and Turnover in Endothelial Cells.

Shear stress and the endothelial transport barrier

"Million of Cracks in Artery Wall" = Leaky Junction