The clinical description of hemophilia can now include impaired cutaneous wound healing, confirms a report published in Blood, the journal of the American Society of Hematologists. A team of scientists from Duke University in Durham, NC, and the University of North Carolina-Chapel Hill has documented that hemophilia B prevents surface wounds from healing at the same rate. The report also sheds light on some of the biological factors that contribute to the complications of wound healing in mice with hemophilia B. Prior to this study, scientists could only speculate that wound healing is impaired by hemophilia B because no published data existed to confirm it.
Difficulties in wound healing may be explained, in part, by the recognition that the chemicals involved in forming blood clots are simultaneously needed to promote wound healing. The report specifically called attention to the special roles of thrombin and fibrin, two key components of blood that are critical in clot formation. Together they help build a hemostatic plug, a collection of platelets and other cells that stop the bleeding and send signals from the injury site to speed up tissue repair. However, insufficient thrombin scaffolds--the molecular infrastructure that provides the framework for blood clots to fill--and poor platelet integration into the structure compromise the quality of hemostatic plugs in people with hemophilia. Consequently, the signal that the thrombin and fibrin initiate to promote proper wound healing is dampened.
Wound healing in people with hemophilia B is also exacerbated by an accelerated rate of blood vessel generation in the tissue. The scientists speculate that this may result from the lower concentration of tissue factors in the deep tissue and the overly persistent action of iron compounds that can contribute to arthropathy, or bleeding in the joints. They further suggest that macrophages, a type of immune cell, may not efficiently remove debris related to clot formation in people with hemophilia B, compromising proper clot formation and healing. This report confirms that the wounds of people with hemophilia B do not heal differently than those in people without a bleeding disorder. It stresses the need to develop better clinical protocols to further address wound healing in people with hemophilia B.
Source: Hoffman M, Harger A, Lenkowski A, et al. Cutaneous Wound Healing is Impaired in Hemophilia B. Blood 2006; 108 (9): 3053-3060.