Leszek Pączek

Rapamycin, unlike cyclosporine A, enhances suppressive functions of in vitro-induced CD4+CD25+ Tregs

BACKGROUND A growing body of data shows that CD4(+)CD25(+) regulatory T cells (Tregs) can induce transplantation tolerance by suppressing immune responses to allograft antigens. However, both the generation and the suppressive capacity of CD4(+)CD25(+) Tregs can be substantially affected by different immunosuppressive drugs used in clinical transplantation. The goal of this study was to compare the effects of cyclosporine A and rapamycin on the induction and suppressive functions of human CD4(+)CD25(+) Tregs in vitro. METHODS CD4(+)CD25(+) Tregs were induced in two-way mixed lymphocyte reaction (MLR) in the presence of rapamycin (Treg-Rapa) or cyclosporine A (Treg-CsA). Tregs were identified in MLR cultures by flow cytometry using anti-CD4, anti-CD25, anti-CTLA-4, anti-CD122, anti-GITR mAbs and ant-PE-FOXP3 staining sets. Suppressive capacity of induced Tregs was evaluated by their capability to inhibit anti-CD3 Ab-triggered proliferation of peripheral blood mononuclear cells (PBMCs), as measured by flow cytometry. The concentration of TGF-beta1 in culture supernatants was measured by enzyme-linked immunosorbent assay. RESULTS Although both rapamycin and cyclosporine A suppressed the induction of CD4(+)CD25(+) Tregs during MLRs, this effect was significantly more pronounced in cells cultured with cyclosporine. On the other hand, only rapamycin significantly decreased the percentage of CD4(+)CD25(+) Tregs which expressed GITR, a negative regulator of Tregs suppressive capacity. Importantly, Treg-Rapa, unlike Treg-CsA, displayed significant suppressive activity and were capable of inhibiting the proliferation of anti-CD3 Ab-activated PBMCs. This activity was likely mediated by TGF-beta1. CONCLUSIONS Rapamycin, unlike cyclosporine A, does not inhibit the function of CD4(+)CD25(+) Tregs. This implies that rapamycin could contribute to the development of transplantation tolerance by promoting the induction of functional CD4(+)CD25(+) Tregs. Moreover, our results suggest that rapamycin could be combined with functional Tregs.

Characterization of bone-marrow-derived rat mesenchymal stem cells depending on donor age

It is generally accepted that autologous transfers, as non‐immunogenic, constitute the safest approach in cellular transplantations. However, this attitude is often associated with the need for isolation and extracorporeal propagation of cells derived from aged patients. Thus the knowledge about relationship between aging and the properties of MSCs (mesenchymal stem cells) is crucial in developing new clinical strategies. The aim of this study was to perform complex comparison of MSC derived from young and aged individuals, which included phenotype, proliferating rate, osteogenic and adipogenic potential and secretory activity. Evaluated populations were isolated from bone marrow of 3‐month‐old and 24‐month‐old rats. There was no significant difference in membrane antigen expression and PDT (population doubling time). Additionally, the adipogenic and osteogenic potential did not vary between studied populations. The reaction of MSCs to either mitogen [bFGF (basic fibroblast growth factor)] or oxidative stress (H2O2) in vitro displayed a very similar pattern in both analysed populations. There was no difference in TGFβ1 (transforming growth factor β1) and VEGF (vascular endothelial growth factor) secretion measured by ELISA test and gene expression evaluated by real‐time PCR. However, the expression of the gene for IL‐1α (interleukin‐1α) was 8‐fold lower in oMSC (MSC isolated from old rats). These results indicate that aging individuals can be considered as candidates for autologous transplantation of bone‐marrow‐derived MSCs.

Uremic toxins impair human bone marrow-derived mesenchymal stem cells functionality in vitro

Mesenchymal stem cells (MSCs) are becoming therapeutic agents of interest in many areas of medicine, including renal diseases and kidney transplantations. However, the effect of uremia on cell properties is still unclear. Therefore, we examined the in vitro influence of uremic toxins, p-cresol (PC) and indoxyl sulfate (IS), on human bone marrow-derived MSC functionality. Cultured MSCs were treated with PC and IS at concentrations corresponding to subsequent stages of chronic kidney disease. Cell viability was characterized by metabolic activity (MTT assay) and proliferation rate (BrdU assay). Apoptosis (Annexin V test) and cell membrane damage (LDH assay) were also tested. MSC secretory properties were determined by measuring cytokine/growth factor levels in media from toxin-treated cells (ELISA). Uremic concentrations of PC and IS resulted in significant inhibition of MSC metabolic activity and proliferation. Toxins did not induce apoptosis, but damaged cell membranes. MSC paracrine activity was also altered - a decrease of VEGF and TGF-β1 levels and an increase in IGF-1 and IL-8 secretion was detected. Presented data indicate a negative influence of uremic toxins on functional characteristics of human bone marrow-derived MSCs. Therefore, their use as autologous therapeutic agents for kidney disease may be questionable and requires further investigations. The observed phenomenon may be attributable to many other MSC therapies, because of the high prevalence of chronic kidney disease in adult population.

Impact of CYP3A4*1B and CYP3A5*3 polymorphisms on the pharmacokinetics of cyclosporine and sirolimus in renal transplant recipients

BACKGROUND Calcineurin inhibitor (cyclosporine, CsA) and mTOR inhibitors (sirolimus, SRL) - immunosuppressants used to prevent allograft rejection after renal transplantation - have a narrow therapeutic index and show considerable inter-individual pharmacokinetic differences. Differences in expression and activity of cytochrome P450 (CYP) 3A4 and 3A5 affect these pharmacokinetics; cytochrome activity differences are associated with CYP genetic polymorphisms. MATERIAL/METHODS This study evaluated the effects of polymorphisms in CYP3A4 and CYP3A5 on immunosuppressive drug-dose adjusted trough blood concentrations. One hundred renal transplant recipients were genotyped for CYP3A4*1B and CYP3A5*3 using PCR-RFLP. Blood concentrations of CsA and SRL were determined by EMIT and HPLC/UV, respectively. RESULTS The allelic frequencies of CYP3A4*1B and CYP3A5*3 in the study group were 2.5% and 96.5%, respectively. The mean cyclosporine dose in CYP3A4*1/*1B subjects was 455.04±128.68 mg/day vs. 261.68±64.72 mg/day in CYP3A4*1/*1 subjects (p<0.001). The mean cyclosporine dose-adjusted trough blood concentrations (ng/ml per mg/kg body weight) in CYP3A4*1/*1B subjects were lower than in the CYP3A4*1/*1 group (37.06±10.38 vs. 44.63±13.99; p<0.218). The mean cyclosporine dose in CYP3A5*1/*3 subjects was 400.65±164.97 mg/day vs. 263.52±64.39 mg/day in CYP3A5*3/*3 subjects (p<0.022). No association was detected between sirolimus trough blood concentration (C0) or dose requirement, and CYP3A4 or CYP3A5 genotype. CONCLUSIONS Genetic polymorphisms in CYP3A4 and CYP3A5 may underlie inter-individual differences in cyclosporine pharmacokinetics after renal transplantation. Patients with at least 1 functional CYP3A5*1 or CYP3A4*1B allele require significantly higher doses of cyclosporine to reach target drug levels compared to patients with the CYP3A4*1 or CYP3A5*3 alleles.

1000 liver transplantations at the Department of General, Transplant and Liver Surgery, Medical University of Warsaw--analysis of indications and results.

THE AIM OF THE STUDY was to analyze indications and results of the first one thousand liver transplantations at Chair and Clinic of General, Transplantation and Liver Surgery, Medical University of Warsaw. MATERIAL AND METHODS Data from 1000 transplantations (944 patients) performed at Chair and Clinic of General, Transplantation and Liver Surgery between 1994 and 2011 were analyzed retrospectively. These included 943 first transplantations and 55 retransplantations and 2 re-retransplantations. Frequency of particular indications for first transplantation and retransplantations was established. Perioperative mortality was defined as death within 30 days after the transplantation. Kaplan-Meier survival analysis was used to estimate 5-year patient and graft survival. RESULTS The most common indications for first transplantation included: liver failure caused by hepatitis C infection (27.8%) and hepatitis B infection (18%) and alcoholic liver disease (17.7%). Early (< 6 months) and late (> 6 months) retransplantations were dominated by hepatic artery thrombosis (54.3%) and recurrence of the underlying disease (45%). Perioperative mortality rate was 8.9% for first transplantations and 34.5% for retransplantations. Five-year patient and graft survival rate was 74.3% and 71%, respectively, after first transplantations and 54.7% and 52.9%, respectively, after retransplantations. CONCLUSIONS Development of liver transplantation program provided more than 1000 transplantations and excellent long-term results. Liver failure caused by hepatitis C and B infections remains the most common cause of liver transplantation and structure of other indications is consistent with European data.

One-year results of a prospective, randomized trial comparing two machine perfusion devices used for kidney preservation.

Studies have shown beneficial effects of machine perfusion (MP) on early kidney function and long‐term graft survival. The aim of this study was to investigate whether the type of perfusion device could affect outcome of transplantation of deceased donor kidneys. A total of 50 kidneys retrieved from 25 donors were randomized to machine perfusion using a flow‐driven (FD) device (RM3; Waters Medical Inc) or a pressure‐driven (PD) device (LifePort; Organ Recovery Systems), 24 of these kidneys (n = 12 pairs; 48%) were procured from expanded criteria donors (ECD). The primary endpoints were kidney function after transplantation defined using the incidence of delayed graft function (DGF), the number of hemodialysis sessions required, graft function at 12 months, and analyses of biopsy. DGF was similar in both groups (32%; 8/25). Patients with DGF in the FD group required a mean of 4.66 hemodialysis sessions versus 2.65 in the PD group (P = 0.005). Overall, 1‐year graft survival was 80% (20/25) vs. 96% (24/25) in the FD and PD groups. One‐year graft survival of ECD kidneys was 66% (8/12) in the FD group versus 92% (11/12) in the PD group. Interstitial fibrosis and tubular atrophy were significantly more common in the FD group – 45% (5/11) vs. 0% (0/9) (P = 0.03) in PD group. There were no differences in creatinine levels between the groups. Machine perfusion using a pressure‐driven device generating lower pulse stress is superior to a flow‐driven device with higher pulse stress for preserving kidney function.

Urethral distension as a novel method to simulate sphincter insufficiency in the porcine animal model

Objectives:  To describe a novel animal model of intrinsic sphincter deficiency.

Rehabilitation and 6-minute walk test after liver transplantation.

BACKGROUND Measurement of exercise capacity is an integral element to assess patients after surgery. Although the 6-minute walk test (6MWT) provides information regarding functional capacity, response to therapy, and prognosis across a range of conditions, its applicability for liver transplant recipients remains to be established. The aim of our study was to examine whether the 6MWT in combination with a subjective rating of perceived exertion (Borg Scale [BS]) could be used to evaluate exercise capacity among patients after liver transplantation (OLT). METHODS Thirteen consecutive subjects were enrolled in this single-center study during routine rehabilitation of the 6MWT and BS. At days 7 and 14 after OLT seeking to assess objective and subjective exercise capacities, we recorded basic clinical parameters, including body weight, blood pressure, heart rate and temperature. The results as compared between days 7 and 14 were related to the reference values for age-, height- and weight-matched healthy subjects. RESULTS On day 7, normal 6MWT was achieved by one patient and at day 14-, by three patients. At days 7 and 14, the average distances of 6MWT were 326.7 m and 421 m, respectively (P<.05), indicating a significant increase in exercise capacity. The average BS rating did not change significantly between days 7 and 14, indicating, that the increased exercise capacity was achieved without excessive effort. CONCLUSIONS Our study indicated that the 6MWT and BS may represent inexpensive and safe assessment methods for exercise capacity after OLT. This evaluation may be helpful to plan and optimize post-OLT rehabilitation.

Safety and Efficacy of Steroid-Free Immunosuppression with Tacrolimus and Daclizumab in Liver Transplant Recipients: 6-Year Follow-up in a Single Center

BACKGROUND Avoidance of steroid therapy after solid-organ transplantation has become a major challenge. Corticosteroid (CS)-free maintenance immunosuppression not only eliminates the well-known adverse effects but also may improve long-term outcome. OBJECTIVE To investigate whether a CS-free regimen of tacrolimus (Tac) in combination with daclizumab (Dac) induction therapy provides adequate coverage after orthotopic liver transplantation. PATIENTS AND METHODS This 6-year, single-center, retrospective study included 25 liver transplant recipients randomized to a Tac/CS regimen (n = 18) vs a Tac/Dac regimen (n = 7) according to the protocol of the MASTER (Monoclonal Antibodies vs STERoids) Study. RESULTS No significant difference was observed in patient and graft survival between treatment arms: 94.4% in the Tac/CS group vs 71.4% in the Tac/Dac group. The incidence of biopsy-proved acute rejection episodes was 23.5% in the Tac/CS group vs 14.3% in the Tac/Dac group (P = NS). Total duration of hospitalization did not differ significantly between groups: 46.5 days in the Tac/CS group vs 73.9 days in the Tac/Dac group. Liver function as estimated using serum alanine aminotransferase and aspartate aminotransferase activity and bilirubin concentration, was not significantly different between the groups during 5 years posttransplantation. However, after 6 years, alanine aminotransferase activity was significantly greater in the Tac/Dac group compared with the Tac/CS group. CONCLUSIONS A CS-free regimen of Tac/Dac is as effective as Tac/Cs in achieving good patient and graft survival. However, no substantial benefits insofar as the safety of Tac/Dac therapy were evident during long-term follow-up.

The Effect of Endoscopic Administration of Autologous Porcine Muscle-derived Cells Into the Urethral Sphincter

OBJECTIVE To verify the fate of autologous porcine myogenic cells after endoscopic administration into the urethral sphincter. METHODS This study was performed on pig animal models. The muscle-derived cells (MDCs) were isolated and identified. After the third passage, the 6 × 10(7) of PKH26 labeled cells were injected into the urethral sphincter using a urethrocystoscope. The urethras were collected after 28 days. To analyze the fate of injected cells, the PKH26 presence, the desmin expression, and the distribution of acetylcholine receptors were evaluated in the tissue sections. Moreover, the maximal urethral closure pressure (MUCP) was assessed in experimental and control groups at day 1 and day 28. RESULTS The isolated porcine MDCs expressed desmin and were able to differentiate into myotubes in vitro. At day 28 after the transplantation, the depots of PKH26-positive cells were observed in the muscular layer, but also in the submucosa. The staining for desmin revealed that cells located in the muscle layer were integrated with muscle fibers that possessed acetylcholine receptors. However, cells administered into nonmuscle tissue did not express desmin. Urethral pressure profilometry demonstrated no significant differences between MUCP in the transplanted group in comparison to the control group at day 28. CONCLUSION The present study demonstrates the successful endoscopic transplantation of myogenic cells into the urethral sphincter. The experiments indicated the key importance of precise cell administration in terms of their fate after the injection.