Credit: UAB Hospital
The protein fibronectin is instrumental in stopping bleeding and preventing life-threatening blood clots, according to preclinical research published in The Journal of Clinical Investigation.
Experiments in mice revealed that plasma fibronectin (pFn) can switch from supporting hemostasis to inhibiting thrombosis.
The researchers said these findings suggest transfusions containing pFn may control bleeding in humans, particularly in association with anticoagulant therapy.
“Most treatments that help the body stop bleeding can actually cause blood clots, and many treatments to prevent excessive blood clots increase [the] risk of bleeding out,” said study author Heyu Ni, MD, of St Michael’s Hospital in Toronto, Ontario, Canada.
“But when given to mice after an injury or to mice treated with blood thinners—which frequently lead to bleeding complications—fibronectin seems to offer a win-win solution.”
Dr Ni and his colleagues began this research by generating mice deficient in both fibrinogen (Fg) and von Willebrand factor (VWF), as well as mice deficient in both VWF and pFn. They then compared these mice to untreated wild-type mice and anticoagulant-treated wild-type mice.
The team discovered that pFn is vital for controlling bleeding in the context of Fg deficiency and supports hemostasis in the context of VWF deficiency. pFn deposition occurred before platelet accumulation (the first wave of hemostasis) in both wild-type and deficient mice.
However, pFn switched its function with regard to platelet aggregation based on the presence or absence of fibrin. pFn inhibited platelet aggregation when fibrin was absent and promoted aggregation when linked with fibrin.
The researchers found that pFn can control the diameter of fibrin fibers, increase the mechanical strength of a blood clot, and be actively involved in thrombosis.
The team said these results provide a solution for the controversy surrounding pFn’s function in hemostasis and establish pFn as a unique regulatory factor in thrombosis. The findings also suggest transfusions containing pFn may prove particularly effective in controlling bleeding.
“Fibrinogen has been shown to help the body stop bleeding, but our research indicates that less-refined blood products that include fibronectin and fibrinogen may help stop bleeding even more effectively,” Dr Ni said. “And, as an added bonus, fibronectin likely also reduces the risk of life-threatening blood clots from forming.”
“There is a lot of work to be done, but we might find that the less expensive and less processed form of donor blood may be more effective for transfusions. We’ve shown that fibronectin might play a role in improving results from transfusions and should not be discarded during blood product processing. It may be also an important protein in transfusions for stopping bleeding, particularly for patients who receive blood thinners during surgeries.”
