Journal Club:Stem cells and Kidney Transplantation

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2. OVERVIEW What are mesenchymal stem cells? Immunomodulatory function of those Cells Clinical use thus far (Bench to Bedside) Trial 3. Use of an induction antibody has grown; in 2009, 58% of patients received a T-celldepleting antibody, 21.2% an interleukin-2 receptor antagonist (IL2-RA), and 3.6%both a T-cell depleting antibody and an IL2-RA; only 17.2% did not receive induction 4. WHAT ARE MSCS Mesenchymal stem or stromal cells (MSCs) are multipotent cells, which can be isolatedfrom various types of tissue, such as bone marrow, adipose tissue and multiple others. 5. IMMUNOMODULATORY EFFECTS OF MSC 6. ANIMAL MODELS studies have demonstrated that skin and heart transplant survival can be prolonged byintravenous infusion of MSCs Organ injury models like improved cardiac function after MI and improved lung functionin rats in a COPD model suggesting MSCs have a regenerative effect on injured organs 7. MECHANISMS OF ACTION act by differentiating into functional cells Paracrine manner - Via the secretion of cytokines, growth factors and prostaglandins withimmune-modulatory and regenerative function MSCs express several chemokine and growth factor receptors, including CXCR4, and thePDGF, HGF and bFGF receptors , suggesting they are capable of migration in responseto inflammation induced chemokine release, and tissue injury. MSCs secrete a range of anti-inflammatory factors, including IL-10, TGFb , hepatocytegrowth factor (HGF), nitric oxide etc. Via HGF they may inhibit fibrosis Direct regenerative function by targeting resident progenitor cells via the secretion ofbFGF, and VEGF 8. EFFECTS ON T CELLS able to suppress T lymphocyte activation and proliferation in vitro Le Blanc etal Scand J Immunol 2003 have been reported to inhibit the cytotoxic effects of antigen-primed cytotoxicT cells Potian et al J Immunol 2003 Di Nicola et al, who found that neutralizing antibodies against TGF- andHGF restored the proliferative response of T cells. Ge et al. showed that administration of MSCs resulted in allograft toleranceas a result of regulatory T-cell generation in a mouse kidney transplant modelThe induction of regulatory T cells was dependent upon the expression ofindolamine 2,3-dioxygenase (IDO) by MSCs 9. DCs generated in the presence of MSCs were impaired in their response to maturationsignals and exhibited no expression of costimulatory molecules. Altered cytokine production pattern, ie decreased production of proinflammatory cytokinestumor necrosis factor (TNF)-, interferon (IFN)-, and interleukin (IL)-12 and increasedproduction of the anti-inflammatory cytokine IL-10 Not only do they block proliferation & differentiation but also antibody production andchemotactic behavior of B cells was affected by MSCs. It has been suggested that MSCs suppress IL-2 or IL-15 driven NK-cell proliferation andIFN- production MSCs exert an inhibitory effect on the NK-cell cytotoxicity 10. Nauta A J , Fibbe W E Blood 2007;110:3499-3506Immunomodulatory effects of MSCs. CTL indicates cytotoxic T cell; HGF, hepatocyte growth factor;IDO, indoleamine 2,3-dioxygenase; PGE2, prostaglandin E2; and TGF-, transforming growth factor2007 by American Society of Hematology . 11. FABRYS DISEASEX-linked genetic disorder - deficiency of lysosomal enzyme alpha-galactosidaseUsing patients own MSCTransduced with a functional galactosidase geneReturn MSC to the patientCorrection of deficiency (Osiris, 2000) 12. OSTEOGENESIS IMPERFECTA Horwitz et al 1999 reported 3 children transplanted with allogeneic MSC from HLA -compatible siblings New lamellar bone formation, improved osteogenesis with fewer fractures Engrafted MSC were shown to differentiate into osteoblasts 13. Multicenter - Between October, 2001, and January, 2007, 55 patients were treated. 39 of 55 patients with steroid-resistant, severe, acute GVHD responded to treatment withmesenchymal stem cells (allogeneic). Over half of patients with a complete response were alive at 2 years. 14. FIGURE 1. Challenges in solid-organtransplantation and possible applicabilityof mesenchymal stem cells (MSCs).The immunomodulatory andregenerative capacities of MSCs aresuggested to be beneficial to amelioratetransplantation related ischemiareperfusion injury, prevent or treatrejection and target allograft pathologyeither directly by immunomodulation orindirectly by decreasing the need forimmunosuppressive medication. 15. purpose of the study was to establish the safety and clinical feasibility of cell-basedtherapy with MSCs in the context of kidney transplantation. Patients were given T cell depleting induction therapy and maintenanceimmunosuppression with cyclosporine and mycophenolate mofetil. On day 7posttransplant, MSCs were administered intravenously. Clinical and immuno-monitoring of MSC-treated patients was performed up to day 360postsurgery. In the two patients given MSCs, but not in the control transplant recipients, thepercentage of memory CD8 T cells markedly decreased posttransplant Despite the two patients given MSCs were receiving CsA, known to prevent thedevelopment of Treg by the inhibition of IL-2 (10,47), a progressive expansion of Treg wasdocumented posttransplant. 16. AIM examining the effect of autologous MSC infusion as analternative to anti-IL-2 receptor antibody for inductiontherapy in adults undergoing living-related donor kidneytransplants. 17. METHODS Single-site prospective, randomized study all donors had a documented linear blood relationship with their respectiverecipient (eg, parent to children and siblings with the same parents) Transplants were performed according to ABO blood compatibility andnegative HLA crossmatch results Blood transfusions were never used before or after the transplants. mean time patients undergo dialysis before transplant is 6.8 or fewer months Patients enrolled from February 2008 through May 2009 18. EXCLUSION CRITERIA systemic infections, prior treatment for cancer, were Pregnant, Obese ([BMI > 28) , abnormal blood chemistries (ie, total cholesterol 300 mg/dL, triglycerides 400 mg/dL,WBC 3000/L, or platelets 75k/L). 19. Treatment groups were identified asgroups A, B, or C to preserve blindingduring statistical analysis.All groups received similar doses of mycophenolate mofetil and steroids. 20. AUTOLOGOUS MSC CULTURES Bone marrow cell aspirates (60-80 mL) were obtained while patients were under localanesthesia from the posterior iliac crest of the kidney recipient 1 month before thetransplant. MSC cultures were tested negative for endotoxin, HCV, hepatitis B virus, HIV, syphilis,fungus, Mycoplasma species, and Chlamydia before infusion. G-banding karyotype analysis was performed to confirm absence of chromosomalaberrations in the final cellular product. MSC suspensions of 1 106/mL were transferred into 20-mL syringes for intravenousinfusion over 15 to 20 minutes. Each participant received autologous MSC infusion (12 106/kg each) 10 minutes beforethe grafts vein and artery were unclamped, and 2 weeks posttransplantation. 21. IMMUNOSUPPRESSION REGIMEN Only the control group received 20 mg of antiIL-2 receptor antibody intravenously within2 hours of surgery and 4 days after surgery. Tacrolimus was initiated at 0.12 mg/kg, targeting trough levels of 8 to 12 mg/kg for thefirst trimester, 5 to 8 mg/kg for the second, and 3 to 7ng/mL for the third trimester andbeyond. Cyclosporine was initiated at 6.5 mg/kg with its target levels (concentration 2 hours afterdose, C2) of 1000 to 1200 ng/mL in the first trimester, 800 to 1000 ng/mL in the secondtrimester, and 600 to 800 ng/mL in the third trimester and beyond. MMF at either 2.0 g/d for patients who weighed 80 kg or more or 1.5 g/d for those whoweighed less than 80 kg. Those in MSC low-dose CNI group received reduced 80% of the standard CNI dose 22. IMMUNOSUPPRESSION REGIMEN Immediately post op and through day 3, patients received 6 mg/kg of methylprednisoloneintravenously, 240 mg/d on day 4, 160 mg/d on day 5, and 80 mg/d on day 6. On days 7 through 14, patients received 30 mg/d of prednisone. Doses were tapered to 20 mg/d for the first trimester, 10 to 15 mg/d for the secondtrimester and 5 to 10 mg/d for the third trimester and beyond. Acute rejection episodes were treated with methylprednisolone pulse therapy. Glucorticoid- resistant rejection was treated with ATG 23. FOLLOW-UP weekly for the first trimester and monthly thereafter for 1year. Acute rejection was defined as an increase of 0.3 mg/dL of serum creatinine (nadircreatinine), confirmed by renal biopsy within 24 hours of initiation of antirejection therapy. Biopsies were read and the severity of lesions was scored by a blinded pathologist andwere classified according to Banff 97criteria. Acute humoral rejection was confirmed bycomplement C4d immune staining in peritubular capillaries. Three participants (2 in the control group and 1 in the autologous MSC low-dose CNIgroup) were lost to follow-up after emigrating from China. They were excluded fromanalysis All participants remained in the study group to which they were assigned, and there wereno missing values from the 12-month follow-up. 24. END POINTS The primary outcome was the incidence of biopsy-confirmed acute rejection andestimated glomerular filtration rate (eGFR) within the first year (as per MDRD). The secondary outcome was 1-year patient and graft survival and the incidence ofadverse events, including opportunistic infections. 25. STATISTICAL ANALYSIS Power and sample size considerations assume a 30% incidence of acute rejection withinthe first year after kidney transplant in China and a reduction to 7.5% with MSC therapybased on the preliminary pilot study performed at our center (data unpublished) adequate power to detect this assumed difference with 53 patients per group (type I error,0.05; 80% power)