Amniotic Fluid: A naturally occurring reservoir of bioactive molecules and its contribution to tissue repair

Amniotic fluid (AF) is a unique multicomponent solution with high dynamicity that enfolds the fetus after the first week of conception. Although during the past few decades remarkable progress has been made in biochemistry of human AF, molecular biology of this vital fluid is beginning to emerge. A broad spectrum of bioactive molecules, ranging from simple molecules such as electrolytes, sugars, lactate and pyruvate, to more complex components such as proteins, lipids, polyamines and RNA are present in AF. Albumin is the major protein in AF as it is in plasma. However, several lines of studies have shown that the plasma protein profile is different from that of AF. In addition to albumin, several groups of functionally important protein, including growth factors, cytokines, hormones, enzymes and immunoglobulins are present in AF, which may play roles in embryonic tissue development and repair. Functional characterization of human AF protein profile, consists of 842 non redundant proteins, has revealed that the proteins are mainly involved in cell migration, growth, proliferation, hyperplasia, signalling, metabolism and immune response. In addition, AF contains different amino acids, arginine and glutamine in particular. Arginine is a molecular precursor for proline and nitric oxide, a gaseous signalling molecule, and glutamine is purines precursor that is essential for highly proliferative cells. Presence of pluripotent stem cells and their products add to the complexity and value of AF to tissue regeneration. Similar to many biological fluids, AF contains several potent anti-bacterial/fungal components such as -defensin, lactoferin, lysozymes and bactericidal protein, classifies this fluid as a bactriostatic solution