<Li> Basement membrane (Type IV) </Li> <Li> Other (Type VI, VII, XIII) </Li> <P> Elastins, in contrast to collagens, give elasticity to tissues, allowing them to stretch when needed and then return to their original state . This is useful in blood vessels, the lungs, in skin, and the ligamentum nuchae, and these tissues contain high amounts of elastins . Elastins are synthesized by fibroblasts and smooth muscle cells . Elastins are highly insoluble, and tropoelastins are secreted inside a chaperone molecule, which releases the precursor molecule upon contact with a fiber of mature elastin . Tropoelastins are then deaminated to become incorporated into the elastin strand . Disorders such as cutis laxa and Williams syndrome are associated with deficient or absent elastin fibers in the ECM . </P> <P> In 2016, Huleihel et al., reported the presence of DNA, RNA, and Matrix - bound nanovesicles (MBVs) within ECM bioscaffolds . MBVs shape and size were found to be consistent with previously described exosomes . MBVs cargo includes different protein molecules, lipids, DNA, fragments, and miRNAs . Similar to ECM bioscaffolds, MBVs can modify the activation state of macrophages and alter different cellular properties such as; proliferation, migration and cell cycle . MBVs are now believed to be an integral and functional key component of ECM bioscaffolds . </P>

What are the major components of the extracellular matrix