Influence of Sirolimus and MMF on Vascular Function and Markers of Cellular Function in Renal Transplant Recipients

Chronic transplant nephropathy and cardiovascular death are the main reasons for loss of transplanted organs after kidney transplantation.

Vascular changes, induced by hypertension and/or immunological processes, determine long time transplant survival.

It will be tested whether the withdrawal of calcineurininhibitors will improve the vessel wall function in renal transplant patients. It is supposed that this immunosuppressive regimen reduces the activation of endothelial cells with important impact on arteriosclerosis and therefore on patient and transplant survival.

Cardiovascular complications and chronic rejection are chief causes of transplant loss\[1,2\]. After renal transplantation patients are still characterized by their pre-existing arteriosclerotic changes \[3\]. Endothelial dysfunction and disturbed distensibility of great arteries are independent predictors of cardiovascular morbidity \[4,5\]. Additionally the activation of sympathetic nervous system leads to dysfunction of vessel wall\[6,7\]. There are important therapeutic options in improvement of endothelial function \[8\].

In addition monocytes of the recipient will contribute to vessel wall changes. \[9-11\]. Aim of therapy - especially of immunosuppressive therapy- have to prevent these fatal vessel wall changes.

Therefore in this study the following topics will be addressed.

1. Discontinuing of calcineurininhibitors will lead to improvement of vessel wall function 2. Sirolimus and Mycophenolat Mofetil affect vessel wall properties in a different way.

3. There are risk factors, e.g. activity of sympathetic nervous system, which may determine the efficacy of discontinuing the calcineurininhibitor concerning the vessel wall function.

4. Calcineurininhibitorfree immunosuppression reduces the activity of endothelial cells.

5. Survival of monocytes and release of procoagulatory activity will be changed by the immunosuppressive regimen.

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Eligibility Criteria:
Inclusion Criteria:

renal transplantation stable function

Exclusion Criteria:

acute rejection