Saliva Activates Coagulation in Persons with Hemophilia A

New Study Provides Insights into Blood Coagulation Mechanisms

AUSTRIA: A recent study conducted by researchers at the Medical University of Vienna has provided new insights into the mechanisms of blood coagulation in individuals with hemophilia A, the most common form of the disorder. According to an article published on ScienceDaily, the research team has discovered that saliva contains special vesicles that can trigger rapid coagulation of blood in hemophilic patients. The findings were recently published in the scientific journal Blood.

Understanding Hemophilia A and its Complications

Hemophilia A is a hereditary blood disorder characterized by a deficiency of factor VIII, a critical component in the blood clotting process. Without sufficient levels of this factor, affected individuals are prone to excessive bleeding, which can become life-threatening if left untreated. Despite the well-documented tendency for joint bleeding in hemophilia A patients, the relatively low incidence of mucosal bleeding in the oral cavity has remained a mystery.

Saliva’s Role in Coagulation

The research team, led by Johannes Thaler and Cihan Ay from MedUni Vienna’s Clinical Division of Hematology and Hemostaseology, alongside Rienk Nieuwland from Amsterdam University Medical Centers, explored the role of body fluids in blood coagulation. Their findings suggest that saliva in hemophilia A patients contains extrinsic tenase complexes located on vesicles. These protein complexes, consisting of tissue factor (TF) and factor VIIa, play a crucial role in initiating the coagulation cascade upon contact with blood.

Analyses conducted by the researchers confirmed that oral mucosal bleeding in hemophilia A patients is rare and typically resolves quickly. Conversely, individuals without these protein complexes in their saliva lack this protective mechanism and are more likely to experience oral mucosal bleeding. “They therefore often suffer from oral mucosal bleeding,” reports Johannes Thaler.

Revisiting Historical Research

The concept of body fluids as activators of blood coagulation was first explored in the 1930s. At that time, the life expectancy of individuals with hemophilia was significantly lower, averaging just eight years. Viennese pediatrician Alphons Solé discovered that maternal milk acted as a potent activator of coagulation. His clinical studies demonstrated that tamponades soaked in maternal milk could rapidly stop severe bleeding in hemophilic patients.

Despite independent confirmation of Solé’s findings, this knowledge was largely forgotten until recently. Researchers, led by Thaler, Ay, and Nieuwland, have revived and expanded upon these historical insights, demonstrating that other body fluids, including maternal milk, amniotic fluid, and urine, also contain extracellular vesicles with extrinsic tenase complexes.

Implications for Future Research and Treatment

The study’s results provide valuable insights into the mechanisms underlying hemophilia A and offer potential avenues for future treatment strategies. “At the same time, they show that it can be very rewarding to re-evaluate historical scientific work in order to develop innovative approaches for research and potentially also for the targeted treatment of patients,” stated Johannes Thaler.

By shedding light on the role of saliva in blood coagulation, the findings open new possibilities for managing mucosal bleeding in hemophilia A patients, potentially reducing the burden of the disorder and improving patient outcomes.