Mimicking Clinical Rejection Patterns in a Rat Osteomyocutaneous Flap Model of Vascularized Composite Allotransplantation

This study introduces a rat model that mimics the rejection patterns observed in human hand transplant patients. By adjusting the dosage of the immunosuppressant tacrolimus, the researchers were able to induce different types of rejection, including acute rejection, chronic rejection, and vasculopathy (disease of the blood vessels). The rat model allows for the study of factors that contribute to rejection and vasculopathy in VCA, such as ischemia-reperfusion injury (IRI) and microvascular changes. This is important because graft loss in VCA is often associated with vasculopathy and chronic rejection, rather than acute rejection. The model can be used to test potential interventions, such as complement blockade, or to study the effects of external trauma or infection on graft survival. This research could lead to improved treatments for VCA patients and a better understanding of the mechanisms underlying rejection and vasculopathy.

• 1
  Transient immunosuppression resulted in severe acute cellular rejection within two weeks of tacrolimus discontinuation, mimicking non-compliance situations.
• 2
  Suboptimal immunosuppression led to chronic skin changes and femoral vasculopathy, similar to clinical presentations.
• 3
  Standard immunosuppression resulted in minimal rejection but subclinical microvascular changes, suggesting vasculopathy starts at the microvascular level.