Anti-endothelial cell antibodies in systemic vasculitis and systemic lupus erythematosus (SLE): effects of heat inactivation on binding and specificity

Heating sera is used to inactivate complement but may affect the binding characteristics of autoantibodies. We studied the effect of heating sera from patients with systemic vasculitides and SLE on antibody binding to cultured human umbilical vein endothelial cells. Sera from 32 patients with systemic vasculitides, eight with SLE and 10 healthy controls were studied for anti-endothelial cell antibodies (AECA) using an ELISA before and after heating sera to 56°C for 30 min. The median (range) AECA binding index in the patient group increased from 20% (0–153%) to 71.5% (10–259%) (P < 0.0001). The AECA binding index in the control group also increased from 14% (0–52%) to 90% (42–154%) (P < 0.0001). The increased binding was unaffected by the addition of fresh complement or removal of immune complexes and the increased binding after heating persisted even after cooling to 4°C. Specificity experiments showed that after heating, the binding specificity of sera was lost. Removal of immunoglobulin with Protein A abolished the increased binding seen after heating. Heating sera increases AECA binding in both patient and control sera. The mechanism is probably non-specific damage to the immunoglobulin molecule, and heating sera should thus be avoided

The role of the mitochondrion in smooth muscle cell fate choices of proliferation versus apoptosis during vascular and cardiovascular diseases

The role of the mitochondrion in cellular metabolism has, in recent years, become more pronounced beyond its traditional role of the energy supplier in the cell. Now the mitochondrion is known to have the duties of biosynthesis, and is involved in programmed cell death (apoptosis). There are pathophysiological incidences where the cell is stressed and must make a choice between survival (including proliferating) and apoptosis. It is unknown how the cell chooses between these two fates, but the mitochondrion may play a role in at least the series of steps leading to apoptosis or proliferation. In this paper it is proposed that the mitochondria may be a lynchpin through which this decision is made. It is suggested that the production of reactive oxygen species (ROS) originating from the mitochondrion may produce the signalling molecules which drive the cell down either a proliferative pathway or one of programmed cell death. These peroxidised molecules may alter the phosphatase/kinase activities in the cell, determine the cell fate and play a central role in the pathogenesis of several vascular pathologies. If so, the mitochondrion may be the key in producing the signalling molecules necessary for dictating cell fate choice