Inhibition of semicarbazide-sensitive amine oxidases decreases lymphocyte infiltration in the early phases of rat liver allograft rejection.

Vascular adhesion protein-1 (VAP-1) has been shown to mediate lymphocyte adhesion to endothelia at sites of inflammation in vitro and in vivo. VAP-1 is also an ectoenzyme with semicarbazide-sensitive amine oxidase (SSAO) activity. In this study we investigated whether inhibition of SSAO influences the inflammatory infiltration in acute rat liver allograft rejection. BN recipients of DA liver allografts were treated with 50 mg/kg/d semicarbazide, an inhibitor of SSAO, or similar volumes of saline. 10 rats/group were followed for graft survival, and 10 rats/group were sacrificed on day 7 post-transplantation for histology and T-lymphocyte isolation. The area percentage of portal inflammatory infiltrates in the grafts was assessed from digital photomicrographs. The proportion of CD4-, CD8- and IL2-receptor positive lymphocytes in the graft was quantified with flow cytometry. On day 7, semicarbazide treatment significantly decreased the inflammatory infiltrate area in the grafts. CD4-, CD8- and IL2-receptor positive cells were equally affected. However, animal survival was not affected. Blockade of the enzymatic activity of VAP-1 has a significant effect on lymphocyte infiltration early in acute liver rejection. Later, activation of other adhesion pathways can by-pass the blockade caused by VAP-inhibition.

Health status of the older population in Estonia.

AIM: To assess the prevalence of physical, depressive, and cognitive disorders in the elderly population in Estonia. METHODS: The prevalence of various common morbidities was determined by a questionnaire sent to 200 general practitioners (GP). GPs were asked to collect data, use medical records, and interview five randomly selected patients (a total of 1,000 people aged 65 years or older). Physical morbidities of older persons were assessed according to their self-reports and reports of their general practitioners. Depressive symptoms and cognitive status were determined by 15-item Geriatric Depression Scale and Mini Mental State Examination, respectively. Response rate was 81%. RESULTS: The prevalences of diseases were as follows: hypertension 63.2%, arthritis 61.3%, ischemic heart disease 56.5% (history of myocardial infarction, 9.8%), heart failure 41.4%, heart rhythm disorders 37.5%, hypercholesterolemia 25.4%, kidney and/or urinary disorders 20.5%, osteoporosis 15.5%, diabetes mellitus 14.9%, chronic airway diseases 13.8% (emphysema 5.8%, asthma 5.5%), hypotension 11.1%, gastroduodenal peptic ulcers 10.6%, thyroid diseases 8.9%, malignant tumors 8.1%, psychiatric disorders 5.7%, and stroke 5.3%. Depressive symptoms were found in 40.3% and cognitive impairment in 22.5% of the elderly persons. CONCLUSIONS: The general structure of diseases in the Estonian elderly population is similar to that of other European countries, but the prevalence of cardiovascular, depressive, and cognitive disorders is much higher.

Sequential analysis of adhesion molecules and their ligands in rat renal allografts during the development of chronic rejection.

Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) are important in endothelial cell-leukocyte interactions. In this sequential study, the expression of ICAM-1 and VCAM-1 and their ligands LFA-1 and VLA-4 as well as major histocompatibility complex class II antigens (MHC class II), and interleukin-2-receptor (IL-2R) were investigated during the development of chronic renal allograft rejection in a rat model. The time-related expression of adhesion molecules and their ligands in the graft was correlated to the chronic allograft damage index (CADI). In association with an initial short immune activation, there was a significant ICAM-1 and VCAM-1 induction in the vascular endothelium and the tubular epithelium. In the interstitium, there was infiltration of lymphocytes expressing ligand molecules VLA-4 and LFA-1, as well as activation markers MHC class II and IL-2R. Thereafter, the expression declined together with the increase of CADI-values. In end-stage chronic rejection, there was practically no expression of ICAM-1 and VCAM-1. In the interstitium, there were only few ligand-expressing leukocytes. In conclusion, adhesion molecules and their ligands are involved in the induction phase of the process but no longer in the later stages of chronic rejection.

Rat cytomegalovirus infection in kidney allograft recipients is associated with increased expression of intracellular adhesion molecule-1 vascular adhesion molecule-1, and their ligands leukocyte function antigen-1 and very late antigen-4 in the graft.

BACKGROUND: Cytomegalovirus (CMV) infection is suggested to be a risk factor for chronic rejection. We have recently shown that rat CMV (RCMV) increases the inflammatory response and accelerates chronic rejection in a model of rat kidney allograft. In this study, the early inflammatory response and time-related expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and their ligands, leukocyte function antigen-1 (LFA-1) and very late antigen-4 (VLA-4), in the grafts were investigated in RCMV-infected rats and compared to noninfected rats developing chronic rejection. METHODS: Transplantations were performed in a rat strain combination of DA (RT1a)->BN (RT1n) receiving triple drug immunosuppression. One group of rats was infected with RCMV, and the other was left uninfected. The grafts were harvested at different time points after transplantation. The adhesion molecules, their ligands and activation markers, MHC class II antigens and interleukin-2-receptors (IL-2-R), were demonstrated by monoclonal antibodies and immunoperoxidase staining from frozen sections of the grafts. Graft histology was evaluated according to the Banff criteria. RESULTS: RCMV caused a significant, prolonged increase of VCAM-1 and ICAM-1 expression in the vascular endothelium compared to the noninfected grafts. Also, the number of cells expressing activation markers, LFA-1 and VLA-4 was significantly enhanced in these animals. Significantly enhanced histological changes of chronic rejection were seen in the RCMV-infected group. CONCLUSIONS: Prolonged, increased expression of ICAM-1 and VCAM-1, and increased numbers of inflammatory cells expressing their ligands in the CMV infected grafts, were associated with accelerated chronic allograft nephropathy.

Development of chronic allograft rejection and arterial hypertension in Brown Norway rats after renal transplantation.

The cardiovascular and renal pathophysiology associated with chronic renal allograft rejection under triple drug immunosuppressive treatment was studied using a recently developed model (Brown Norway (BN) rats) in a 6-week experiment. Renal transplantation was performed to 10-week-old rats in a rat strain combination of Dark Agouti (DA) --> BN. The right kidney was removed from another group of BN rats (uninephrectomized). A triple drug treatment comprising cyclosporine (10 mg/kg subcutaneously, s.c.), azathioprine (2 mg/kg s.c.) and methylprednisolone (1.6 mg/kg s.c.) was given to each rat daily for 6 weeks. A control group underwent no operations nor drug treatment. After the transplantation, the systolic blood pressure in this group was increased from 116 +/- 2 to 166 +/- 2 mmHg, while in the uninephrectomized group the rise was from 115 +/- 4 to 146 +/- 4 mmHg, and no change was observed in the blood pressures of the control group. The vascular relaxation responses of mesenteric arterial rings in vitro to acetylcholine were inhibited in both the transplantation group and the uninephrectomized group as compared with the control group, but few significant differences were found in the contraction responses to noradrenaline and potassium chloride. Graft histology was examined after 6 weeks, quantified by using the chronic allograft damage index (CADI). Changes specific to a chronic rejection reaction were observed in the allografts (CADI mean 6.0) but no injuries were seen in the rats' own kidneys (CADI mean 1.2). Our findings show that allograft rejection in BN rats after renal transplantation is associated with the development of arterial hypertension. The combination of cyclosporine, methylprednisolone and azathioprine also rises blood pressure in uninephrectomized BN rats. The hypertensive effects of the drug treatment and graft rejection are associated with endothelial dysfunction.

Time-related effects of cytomegalovirus infection on the development of chronic renal allograft rejection in a rat model.

Cytomegalovirus (CMV) infection is a risk factor for chronic allograft rejection. The histological findings of chronic renal allograft rejection include inflammation, vascular intimal thickening, glomerulosclerosis, tubular atrophy and fibrosis. We have developed a rat model of renal transplantation in which transplants, after an early inflammatory episode, end up with chronic rejection within 60 days. During the early phase of the process in this model, CMV increased and prolonged the inflammatory response, the expression of adhesion molecules, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 and their ligands, lymphocyte function antigen-1 and very late antigen-4 in the graft. Simultaneously, the production of various growth factors, such as transforming growth factor beta, platelet-derived growth factor and connective tissue growth factor was upregulated, which induce smooth muscle cell proliferation in the vascular wall and collagen synthesis by fibroblasts. Chronic rejection developed within 20 days in CMV-infected grafts. In summary, CMV infection accelerated and enhanced the early immune response, the induction of growth factors and collagen synthesis, and the development of chronic rejection in renal allografts.

An experimental model of chronic renal allograft rejection in the rat using triple drug immunosuppression.

BACKGROUND: Chronic rejection is a major problem in renal transplantation. Various experimental models have been developed to study vasculopathy of chronic rejection. However, animal models resembling the clinical situation of renal transplantation with combination therapy of basic immunosuppression are not available. The aim of this study was to find an experimental model of a donor-recipient rat strain combination that, under triple drug immunosuppressive treatment (methylprednisolone, cyclosporine, and azathioprine), would develop chronic rejection within a few weeks. METHODS: Renal transplantations were performed in strain combinations of DA-->AO, PVG-->BN, and DA-->BN. In each group, 5-8 animals received triple drug treatment of methylprednisolone (2 mg/kg), azathioprine (2 mg/kg), and cyclosporine (5 mg/kg) daily, 5-10 animals were left without treatment, and 6 syngenic transplantations were performed. The grafts were monitored with ultrasound-guided fine needle aspiration biopsies to quantify the inflammation in the graft. Graft histology was performed in parallel and quantified by using the chronic allograft damage index (CADI). RESULTS: In nonimmunosuppressed animals, irreversible acute rejection with a high peak of inflammation appeared in every strain combination within 5-8 days. In triple drug-treated rats, the DA-->AO combination demonstrated a prolonged acute rejection but no characteristic chronic changes, and the PVG-->BN combination showed practically no inflammation and did not develop any signs of chronic rejection within 60 days (CADI: 2.7+/-2.1), but the DA-->BN combination showed an early, mild inflammatory response 5-7 days after transplantation and developed chronic rejection within 40-60 days after transplantation (CADI: 7.9+/-3.1). Syngenic animals showed no inflammation or histological alterations (CADI: 1.7+/-2.0). CONCLUSIONS: In conclusion, in the DA-->BN combination with triple drug treatment, early mild inflammation was followed by the development of chronic rejection and can be used as an experimental model that resembles the clinical situation in renal transplantation.

Effect of cytomegalovirus on an experimental model of chronic renal allograft rejection under triple-drug treatment in the rat.

BACKGROUND: Cytomegalovirus (CMV) infection is thought to be a risk factor of chronic rejection. In clinical studies and animal models, mainly concerning graft vasculopathy, CMV has been demonstrated to enhance allograft arteriosclerosis. In this study we have investigated the effect of CMV on the early inflammatory response and graft histology in an experimental model of renal transplantation in a rat strain combination that develops chronic rejection under triple-drug immunosuppression. METHODS: Renal transplantations were performed in a rat strain combination of DA-->BN receiving triple-drug treatment (2 mg/kg methylprednisolone, 2 mg/kg azathioprine, 5 mg/kg cyclosporine daily subcutaneously). One group of immunosuppressed animals was infected with rat CMV, the Maastricht strain (10(5) plaque-forming units intraperitoneally), and the other group was left uninfected. As a positive control for alloresponse, one group of recipients received neither immunosuppression nor virus. Syngenic transplantations with triple-drug treatment and CMV were used as negative controls. The grafts were monitored by frequent ultrasound-guided fine-needle aspiration biopsies, and the intragraft inflammation was quantified in detail by the increment method and expressed in corrected increment units (CIU). Graft histology was performed in parallel. RESULTS: Nonimmunosuppressed animals developed acute rejection with a high peak of inflammation (7.9+/-3.2 CIU), a typical blast response, and lymphocytosis followed by infiltration of macrophages and necrosis within 7 days. Triple drug-treated animals had a short, mild inflammatory response (3.3+/-1.4 CIU at the peak) in the graft 3-5 days after transplantation but ended up with histological changes characteristic of chronic rejection with vasculopathy and fibrosis 40-60 days later. Triple drug-treated animals with CMV demonstrated a significantly stronger inflammation (4.5+/-1.8 CIU, P<0.01) than those without, and lymphoid activation continued longer and was followed by infiltration of macrophages in the graft. CMV infection of the graft was demonstrated by viral culture and antigen detection. In histology, chronic rejection with intimal thickening of arteries and arterioles and medial necrosis of large arteries was seen at 14 days, ending up with remarkable graft fibrosis within 20 days after transplantation. CONCLUSION: CMV prolonged and increased graft inflammation and accelerated chronic rejection of renal allografts under triple-drug treatment.

Evidence that thymectomized, bone marrow-reconstituted rats do not reject their allografts.

We have investigated the reasons why thymectomized, bone marrow-reconstituted (B) rats do not reject their allografts, by comparing the structure of inflammation and functions of inflammatory cells in nonrejecting allografts to rejecting allografts in normal control recipients. The results demonstrate that B recipients mount a specific cellular response towards the graft. The response in B recipients differs from that in normal controls by a smaller intensity of inflammation, fewer blast cells, and activated mononuclear phagocytes in the inflammatory infiltrate, as well as a delay in the appearance of specific donor-directed lytic activity in the graft. B rats also have fewer blast cells and an inverted CD4/8 ratio in the spleen. There is no obvious absence of any given cell type or cellular function in the graft inflammatory infiltrate. In light of these results no cell type responsible for allograft nonrejection can be pinpointed.