Wharton’s Jelly (WJ) is the gelatinous substance that forms the bulk of the umbilical cord, surrounding the blood vessels that connect a developing fetus to the placenta. This material acts as a protective cushion and structural support system for the two umbilical arteries and the single umbilical vein. Named after the English physician Thomas Wharton, who first described it in 1656, WJ ensures the continuous, unobstructed transfer of nutrients, oxygen, and waste between the mother and the fetus. WJ’s composition and function are now being explored for uses in regenerative medicine.
Composition and Structure of Wharton’s Jelly
Wharton’s Jelly is classified histologically as mucoid connective tissue, due to its high proportion of extracellular matrix components compared to its relatively low cellular content. The material’s characteristic jelly-like consistency comes primarily from a ground substance rich in mucopolysaccharides, specifically hyaluronic acid and chondroitin sulfate. These molecules are highly hydrophilic, meaning they attract and hold a significant amount of water, creating the turgid, hydrated matrix that provides the umbilical cord’s bulk and cushioning ability.
Interspersed within this gelatinous matrix are collagen fibers, including types I, III, V, and VI, which provide structural integrity and elasticity to the cord. The cell population within the jelly is sparse but includes specialized fibroblast-like cells and myofibroblasts. These cells contribute to the maintenance of the extracellular matrix and possess characteristics that identify them as mesenchymal stem cells, which are of high interest in modern therapeutic applications. The combination of the water-retaining ground substance, the structural collagen, and the scattered cells forms a resilient, protective sheath around the delicate umbilical vasculature.
Essential Biological Functions
The primary natural function of Wharton’s Jelly is to provide mechanical protection to the vessels running through the umbilical cord. The thick, turgid structure of the jelly absorbs external pressures and shields the two arteries and one vein from compression, kinking, or knotting that could occur due to fetal movement within the amniotic fluid. This cushioning effect maintains the patency of the vessels, ensuring the uninterrupted flow of oxygenated and nutrient-rich blood to the fetus and the return of deoxygenated blood and waste products to the placenta.
Beyond its protective role during gestation, Wharton’s Jelly has a distinct physiological function immediately following birth. Upon exposure to the cooler environment outside the mother’s body, the jelly undergoes a thermal reaction that causes it to swell or contract. This physical change naturally constricts the umbilical vessels embedded within the matrix, which facilitates the physiological cessation of blood flow between the placenta and the newborn. This natural closure mechanism is a fundamental part of the transition from fetal to neonatal circulation.
Clinical Relevance in Modern Medicine
The natural function of Wharton’s Jelly after birth directly informs the modern obstetrical practice of delayed cord clamping. By allowing the cord to remain intact for a short period after delivery, the physiological closure mechanism has time to complete, maximizing the transfer of placental blood to the newborn. This practice is associated with significant benefits for the infant, including increased iron stores during the first months of life and a reduced risk of anemia, particularly in term infants.
Outside of obstetrics, Wharton’s Jelly has gained considerable attention as a rich source of Mesenchymal Stem Cells (MSCs). These stem cells can be easily isolated from the umbilical cord tissue, making collection non-invasive. Wharton’s Jelly-derived MSCs exhibit high proliferative capacity and a primitive state compared to adult stem cells, such as those derived from bone marrow.
These cells display potent immunomodulatory properties and low immunogenicity, making them attractive candidates for allogeneic (non-self) transplants without the risk of immune rejection. Research is actively exploring their therapeutic potential in regenerative medicine for conditions ranging from neurological disorders and joint injuries to immune-mediated diseases.