Gareth R. Bicknell

Differential expression of cytoprotective and apoptotic genes in an ischaemia‐reperfusion isolated organ perfusion model of the transplanted kidney

The optimal kidney preservation system and methods to ameliorate reperfusion injury are major factors in accomplishing successful graft function following transplantation. Ischaemia and reperfusion lead to cellular stress and the adaptive response may include the activation of genes involved in cellular protection and/or cell death by apoptosis. We investigated the expression of cytoprotective heme oxygenase‐1 (HO‐1), anti‐apoptotic Bcl‐2 and pro‐apoptotic Bax after 6u2003h isolated organ perfusion in porcine kidneys that had been given 10 and 40u2003min warm ischaemic time. The level of HO‐1 was shown to be significantly higher in the 10‐min warm ischaemic group compared with 40‐min group (0.90u2003±u20030.03 vs. 0.83u2003±u20030.03; Pu2003=u20030.002). The levels of HO‐1 showed a significant positive correlated with parameters of renal function, creatinine clearance, and renal blood flow and urine output (AUC; ru2003=u20030.8042, Pu2003=u20030.03; ru2003=u20030.6028, Pu2003=u20030.04; ru2003=u20030.6055, Pu2003=u20030.04), demonstrating a possible protective role of this gene in this model of renal transplantation.

Inactive matrix metalloproteinase 2 is a normal constituent of human glomerular basement membrane. An immuno‐electron microscopic study

Remodelling of the extracellular matrix requires tight control not only of matrix synthesis, but also of matrix degradation. Control of matrix degradation is achieved mainly through the matrix metalloproteinase (MMP) enzymes. In the glomerulus, MMP‐2 and MMP‐9 are believed to be particularly important, as they have activity against type IV collagen. This study has demonstrated by immuno‐electron microscopy that most of the immunoreactivity for MMP‐2 in the normal glomerulus is located within the glomerular basement membranes and mesangial matrix. mRNA for MMP‐2 is also detectable in normal glomeruli, but the other main gelatinase, MMP‐9, could not be localized by immuno‐electron microscopy. In the normal glomerulus, it seemed likely that MMP‐2 is present in an inactive form. To confirm this, in situ zymography was carried out using frozen sections of normal kidney. Baseline activity of normal kidney was relatively weak, but this was dramatically increased by chemical activation of metalloproteinases. The results imply that MMP‐2, in an inactive form, is a normal constituent of the extracellular matrix and glomerular basement membranes. Activation would presumably render the matrix ‘self‐degrading’; membrane‐bound MMPs (MT‐MMPs) seem particularly likely to be involved in leukocyte penetration of basement membranes in inflammation. Copyright