Jose MD, Ikezumi Y, van Rooijen N, Atkins RC, Chadban SJ. Macrophages act as effectors of tissue damage in acute renal allograft rejection.
Transplantation 2003;
76:1015-22. [PMID:
14557746 DOI:
10.1097/01.tp.0000083507.67995.13]
[Citation(s) in RCA: 105] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND
Macrophages constitute 38% to 60% of infiltrating cells during acute renal allograft rejection. Their contribution to tissue damage during acute rejection was examined by depleting macrophages in a rat model.
METHODS
Lewis rats underwent bilateral nephrectomy and then received a Dark Agouti renal allograft and liposomal-clodronate, control phosphate-buffered saline liposomes, or saline intravenously (n=7 per group) on days 1 and 3 postsurgery. Grafts were harvested on day 5.
RESULTS
Liposomal-clodronate treatment resulted in a 70% reduction in blood ED1+ monocytes and 60% reduction in intragraft ED1+ macrophages (both P<0.01). Half of all remaining interstitial ED1+ cells were undergoing apoptosis (terminal deoxynucleotide transferase-mediated dUTP nick-end labeling+/ED1+), and thus functional depletion of more than 75% of macrophages was achieved. Histologic and functional parameters of acute rejection were attenuated: interstitial infiltrate, tubulitis, and glomerulitis (P<0.01); tubular cell apoptosis (P<0.001); tubular cell proliferation (P<0.001); and serum creatinine (P<0.01). Production of inducible nitric oxide synthase by infiltrating cells and urinary nitric oxide excretion was reduced by 90% (P<0.001). In contrast, no reduction in the number of other leukocytes was seen (CD3+, CD4+, CD8+, and natural killer cells). Activation of lymphocytes (CD25+) and production of lymphocyte effector molecules (granzyme B) were unaltered.
CONCLUSION
This study demonstrates that macrophages contribute to tissue damage during acute rejection.
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