IADR Abstract Archives
Periodontitis Sera Containing Anticardiolipin Displace Annexin V From Phosphatidylserine
Objectives: Antiphospholipid antibodies are associated with adverse pregnancy outcomes, including spontaneous abortion, fetal growth retardation, prematurity, and preeclampsia. Anticardiolipin (aCL), an antiphospholipid found in patients with SLE and the Antiphospholipid Syndrome (APS), is present in elevated levels in 15-20% of patients with periodontitis. The target antigen of autoimmune aCL is β2GPI, which is a phospholipid binding serum protein. In APS, one proposed mechanism for antiphospholipid-mediated miscarriages involves the binding of aCL-β2GP1 complexes to phosphatidylserine (PS) on the surface of rapidly dividing trophoblasts. This can disrupt the Annexin V “protective shield” that normally protects trophoblasts from fibrin clot formation and leads to down-regulation of hCG secretion, decreased invasiveness, inhibition of proliferation, and increased apoptosis.
Methods: We examined the ability of human sera from 19 periodontitis patients (13 with chronic periodontitis and 6 with generalized aggressive periodontitis) and 10 healthy subjects to displace Annexin V from the surface of a PS-coated microtiter plate. Twelve periodontitis patients and one healthy subject had elevated (>15 U/ml) aCL levels. Sera containing biotin-labelled Annexin V were incubated in microtiter plates coated with PS, and relative concentrations of bound Annexin V were determined following further incubation with alkaline phosphatase-conjugated Extravidin.
Results: Annexin V binding to PS was significantly lower for all samples testing positive for aCL (p=.02). For patients with periodontitis, Annexin V binding to PS was significantly lower for patients testing positive for aCL (p=.008).
Conclusions: Sera from patients with chronic and aggressive periodontitis testing positive for aCL compete with Annexin V for binding to a PS-coated surface. Since some periodontal pathogens, including P. gingivalis, can induce aCL due to molecular mimicry of key peptides in β2GPI, and this mechanism is proposed to be important in obstetric APS complications, it is possible that some of the observed obstetric complications of periodontitis could be due to aCL.
Methods: We examined the ability of human sera from 19 periodontitis patients (13 with chronic periodontitis and 6 with generalized aggressive periodontitis) and 10 healthy subjects to displace Annexin V from the surface of a PS-coated microtiter plate. Twelve periodontitis patients and one healthy subject had elevated (>15 U/ml) aCL levels. Sera containing biotin-labelled Annexin V were incubated in microtiter plates coated with PS, and relative concentrations of bound Annexin V were determined following further incubation with alkaline phosphatase-conjugated Extravidin.
Results: Annexin V binding to PS was significantly lower for all samples testing positive for aCL (p=.02). For patients with periodontitis, Annexin V binding to PS was significantly lower for patients testing positive for aCL (p=.008).
Conclusions: Sera from patients with chronic and aggressive periodontitis testing positive for aCL compete with Annexin V for binding to a PS-coated surface. Since some periodontal pathogens, including P. gingivalis, can induce aCL due to molecular mimicry of key peptides in β2GPI, and this mechanism is proposed to be important in obstetric APS complications, it is possible that some of the observed obstetric complications of periodontitis could be due to aCL.