Amelioration of renal damage by administration of anti-thymocyte globulin to potential donors in a brain death rat model

Abstract

Brain death (BD), a non-immunological factor of renal injury, triggers an inflammatory process causing pathological signs of cell death in the kidney, such as necrosis and apoptosis. Kidneys from brain dead donors show lower success rates than kidneys from living donors and one strategy to improve transplantation outcome is to precondition the donors. For the first time, anti-rat thymoglobulin (rATG) was administered in an experimental brain death animal model to evaluate if it could ameliorate histopathological damage and improve organ function. Animals were divided into three groups: V (n=5) ventilated for 2h; BD (n=5) brain death and ventilated for 2h; and BD+rATG (n=5) brain death, ventilated for 2h, rATG was administered during brain death (10mg/kg). We observed lower creatinine levels in treatment groups (means): V, 0·88±0·22 mg/dl; BD, 1·37±0·07 mg/dl; and BD+rATG, 0·64±0·02 mg/dl (BD versus BD+rATG, P<0·001). In the BD group there appeared to be a marked increase of ATN, whereas ATN was decreased significantly in the rATG group (V, 2·25±0·5 versus BD, 4·75±0·5, P<0·01; BD+rATG, 2·75±0·5 versus BD 4·75±0·5 P<0·01). Gene expression was evaluated with reverse transcription-polymerase chain reaction; tumour necrosis factor (TNF)-α, interleukin (IL)-6, C3, CD86 showed no significant difference between groups. Increased IL-10 and decreased CCL2 in BD+rATG compared to BD (both cases P<0·01). Myeloperoxidase was increased significantly after the brain death setting (V: 32±7·5 versus BD: 129±18). Findings suggest that rATG administered to potential donors may ameliorate renal damage caused by BD. These findings could contribute in the search for specific cytoprotective interventions to improve the quality and viability of transplanted organs.

Fig. 1

Mean blood pressure evolution. Shown are changes in mean blood pressure during brain death induction in rats. After brain death was diagnosed, animals were ventilated for 2 h; during that time, blood pressure was kept constant within 60–120 mmHg. In the cases of hypotension, animals were treated with noradrenaline. Similar levels were kept for the ventilated group (data not shown).

Fig. 2

Urea and creatinine scores. Two h after brain death (BD) was diagnosed, blood samples were collected and urea (a) and creatinine (b) were evaluated. Data are expressed as mean ± standard deviation (s.d.), n = 5. **P < 0·01 and ***P < 0·001 for comparison with the BD group.

Fig. 3

Acute tubular necrosis (ATN) quantification. (a) ATN score in the three experimental groups. Tables show mean ± standard deviation values (s.d.) of all animals in the three groups. **P < 0·005 compared to the brain death group (BD). (b) Haematoxylin and eosin (H&E) staining, original magnification ×20. Ventilated (V) group: ATN 20% of parenchyma. Flattened focal tubular epithelium and variable dilatation observed. BD group: ATN 70% of parenchyma. Denudation of epithelial membrane and haemorrhage focus. BD+rATG group: ATN 30% of parenchyma. Expanded tubules with intraluminal cell casts and loss of epithelial membrane or replacement by squamous epithelium. (c) Renal polymorphonuclear (PMN) infiltration was analysed with myeloperoxidase (MPO) activity determinations. Results are expressed as units of MPO/mg of protein. Data are expressed as mean ± standard deviation (s.d.), n = 5. *P < 0·05 and for comparison with BD group versus BD+rATG.

Fig. 4

Determination of inflammatory mediators. Intrarenal levels of mRNA for tumour necrosis factor-alpha, interleukin (IL)-6, IL-10, monocyte chemotactic protein 1 (MCP-1), C3 and CD86 in kidneys from brain death group (BD) and treatment group (BD+rATG). *P < 0·05 and ***P < 0·001 comparing BD versus BD+rATG.