P. T. R. van Suylichem

Induction of organ dysfunction and up-regulation of inflammatory markers in the liver and kidneys of hypotensive brain dead rats: a model to study marginal organ donors.

BACKGROUND Marginal donors exposed to the full array of effects induced by brain death are characterized by low success rates after transplantation. This study examined whether organs from marginal brain dead animals show any change in organ function or tissue activation making them eventually more susceptible for additional damage during preservation and transplantation. METHODS To study this hypothesis we first focused on effects of brain death on donor organ quality by using a brain death model in the rat. After induction of brain death, Wistar rats were ventilated for 1 and 6 hr and then killed. Sham-operated rats served as controls. Organ function was studied using standard serum parameters. Tissue activation of liver and kidney was assessed by staining of immediate early gene products (IEG: FOS, JUN), and inflammatory markers; cell adhesion molecules (Intercellular adhesion molecule-1, vascular cell adhesion molecule-1), leukocyte infiltrates (CD45, T cell receptor, CD8, CD4), and MHC class II. RESULTS During brain death progressive organ dysfunction was observed that coincided with a significant increase in activation of immediate early genes, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, CD45, and MHC class II versus nonbrain dead controls. In liver tissue also the markers for T cell receptor and CD8 significantly increased. CONCLUSIONS These findings suggest that an immune activation with increased endothelial cell activation and immediate early gene expression occurs in marginal donors after brain death induction. We suggest that brain death should not longer be regarded as a given nondeleterious condition but as a dynamic process with potential detrimental effects on donor organs that could predispose grafts for increased alloreactivity after transplantation.

Distribution of collagens type I, type III and type V in the pancreas of rat, dog, pig and man

The presence of collagens type I, type III and type V was determined immunohistochemically in pancreatic tissue of rat, pig, dog and man. The reaction to anti-collagen type I is weak (pig, dog) or moderate (rat, man) in the peri-insular region and in the lobar, lobular and acinar septa, whereas the reaction to anti-collagen type III is well developed. In rat and dog, the latter reaction deposit on the lobar and acinar septa is prominent. These elements only show a moderate reaction intensity in pig and man. The peri-insular region displays a weak (rat, dog, man) or very weak (pig) reaction against collagen type III. Anti-collagen type V reacts moderately (rat, dog, man) or weakly (pig) in the lobar and lobular septa. The acinar septa show a moderate (rat, dog, man) or very weak (pig) reaction. This information regarding the types and distribution of the collagenous compounds in pancreatic extracellular matrix could lead to differentiated enzymatic pancreas dissociation and, ultimately, increased islet yield and improved reproducibility of pancreatic islet isolation procedures for transplantation purposes.

Insulin secretion by rat islet isografts of a defined endocrine volume after transplantation to three different sites

SummaryWe have analysed the graft function of rat islet isografts of identical and well-defined endocrine volumes after transplantation to three different sites (kidney, liver and spleen). Graft endocrine mass was determined by measuring the total islet volume prior to transplantation and was chosen to be similar to the endocrine volume in the normal adult rat pancreas. Graft function was tested in unanaesthetized, unstressed rats by the responses to glucose infusion and to a meal. All transplanted animals returned to normoglycaemia within one week after transplantation. At one month, basal glucose and insulin levels were similar to controls in rats with grafts to the spleen, but higher in rats with grafts to the kidney or liver. Irrespective of the transplantation site, recipients had higher glucose and lower insulin levels than controls in response to glucose infusion, but in response to a meal these differences from normal were less obvious. Finally, recipients showed both an acute insulin response to glucose infusion as well as a pre-absorptive insulin release after food ingestion, irrespective of the transplantation site. Our findings indicate that the insulin response to glucose infusion and to a meal is quantitatively reduced, but qualitatively intact after transplantation to the kidney, liver or spleen.

Induction of organ dysfunction and activation of inflammatory markers in donor liver and kidney during hypotensive brain death

ESULTS after transplantation with kidneys received from living-related or living-unrelated donors are far superior to the outcome after cadaveric organ transplantation. 1 This fact cannot be explained only by HLA matching or shorter cold ischemia times and might be due to the state of brain death (BD) in the donor. Although BD is still considered a static and given condition, it is known to have definite effects on hemodynamic stability, hormone regulation, and inflammatory reactivity. BD may initiate a cascade of events that predisposes for additional injury during preservation, reperfusion, and after transplantation. The latter may be enhanced in marginal cadaveric donors which are subjected to BD and to proven detrimental effects of hypotension. We have developed a rat BD model, mimicking the marginal donor situation in humans. In this study, we used this model to investigate the combined effects of BD and hypotension on endothelial cell expression of cell adhesion molecules (ICAM-1, VCAM-1). Also, we studied the presence of leukocyte infiltrates (CD45, TcR, CD8, CD44) and the expression of MHC class II in kidney and liver after BD induction.

Islet transplantation in diabetic rats normalizes basal and exercise-induced energy metabolism

SummaryTransplantation of islets of Langerhans in diabetic rats normalizes resting glucose and insulin levels, but it remains unclear whether islet transplantation restores resting and exercise-induced energy metabolism. Therefore, we compared energy metabolism in islet transplanted rats with energy metabolism in normal controls and in streptozotocin-induced diabetic rats. Indirect calorimetry was applied before, during, and after moderate swimming exercise. Blood was sampled by means of a heart catheter for determination of nutrient and hormone concentrations. In islet transplanted rats, the results from indirect calorimetry and the nutrient and hormone concentrations were similar to the results in normal controls. In resting diabetic rats, insulin levels were very low, while glucose levels were exaggerated. Compared to resting controls, fat oxidation and energy expenditure were elevated, but carbohydrate oxidation was similar. Exercise increased energy expenditure and was similar in diabetic and control rats. Carbohydrate oxidation was lower and fat oxidation was higher in diabetic than in control rats. Exercise-induced increments in glucose, lactate and non-esterified fatty acid levels were the highest in diabetic rats. Thus, at rest, but not during exercise, insulin influences energy expenditure. Insulin reduces lipolysis and glycogenolysis. It enhances the relative contribution of carbohydrate oxidation and reduces fat oxidation to total energy expenditure, at rest and during exercise. Absence of insulin enhances anaerobic glycolytic pathways during exercise. It is concluded that in diabetic rats, islet transplantation of 50% of the normal pancreatic endocrine volume successfully normalizes insulin levels and hence energy metabolism at rest and during exercise.