Wharton’s Jelly is a specialized, gelatinous substance found exclusively within the human umbilical cord. This unique connective tissue completely encases the cord’s blood vessels: one large umbilical vein and two smaller umbilical arteries. The jelly serves as a protective matrix, supporting the vessels that connect the developing fetus to the placenta. It is entirely derived from the extra-embryonic mesoderm.
The Unique Composition and Structure
This specialized material is histologically classified as a type of mucous connective tissue, distinct from the dense or loose connective tissues found elsewhere in the body. The physical makeup of Wharton’s Jelly is dominated by its extracellular matrix (ECM), a complex scaffold that provides its characteristic jelly-like consistency and volume. The ECM is rich in mucopolysaccharides, also known as glycosaminoglycans.
A significant component is hyaluronic acid, which binds large amounts of water, contributing to the jelly’s turgor and cushioning effect. Other glycosaminoglycans, such as chondroitin sulfate, are also present, contributing to the structure’s volume and viscoelastic properties. Embedded within this hydrated matrix are specialized cells, often called Wharton’s Jelly Fibroblasts or myofibroblasts. These cells synthesize and maintain the components of the ECM. The matrix also contains various types of collagen fibers, predominantly Type I and Type III, which provide structural integrity.
Essential Biological Role During Pregnancy
The primary function of Wharton’s Jelly is to act as a physical buffer, protecting the delicate umbilical vessels throughout gestation. This mechanical protection is achieved through the jelly’s inherent rigidity and volume, creating a resilient cushion around the umbilical vein and arteries. The cushioning prevents the blood vessels from being compressed, kinked, or twisted during fetal movement or uterine contractions.
Maintaining the patency (openness) of these vessels is necessary for the continuous flow of blood. The umbilical vein delivers oxygen and nutrient-rich blood from the placenta to the fetus, while the two umbilical arteries return waste products and deoxygenated blood back to the placenta. The structural integrity provided by the jelly ensures that this bi-directional exchange remains consistent for healthy fetal development. The thickness of the jelly is often most pronounced in the amniotic portion of the cord, providing enhanced protection where fetal movement is most frequent.
Beyond its primary role as a mechanical shield, the jelly also serves a secondary function to maintain the cord’s temperature. Immediately following birth, the sudden exposure to cooler ambient air causes the Wharton’s Jelly to cool and rapidly change its structure. This response leads to a reduction in volume and a collapse of the surrounding structures. This acts as a natural, physiological clamp on the umbilical vessels, slowing blood flow and contributing to delayed cord clamping.
Clinical Applications and Stem Cell Potential
Following delivery, Wharton’s Jelly becomes important as a rich and accessible source for adult stem cells. The tissue contains a high concentration of Mesenchymal Stem Cells (MSCs), which are distinct from the Hematopoietic Stem Cells found in umbilical cord blood. These Wharton’s Jelly-derived MSCs (WJ-MSCs) are valuable because they retain a high potential for proliferation and possess multipotency. This means they can differentiate into various cell types, including bone, cartilage, fat, and nerve cells.
WJ-MSCs exhibit powerful immune-modulating properties and a low risk of rejection, making them promising for allogeneic (non-matched) transplantation therapies. They secrete bioactive molecules, such as growth factors and cytokines, which promote tissue repair and enhance angiogenesis. Researchers are exploring the use of WJ-MSCs in regenerative medicine for conditions like joint pain, neurological disorders, and tissue damage. The ease of harvesting this tissue, which is normally discarded as medical waste, makes Wharton’s Jelly a sought-after resource for research and cord banking.