Suppressive effects of vitamin C-treated induced-regulatory T cells on heart allograft rejection under vitamin C-deficient or -sufficient conditions.

Foxp3 stability of vitamin C-treated induced-regulatory T cells (V-iTregs) is superior to that of conventional iTregs (C-iTregs). However, the role of V-iTregs in allograft rejection under vitamin C-deficient conditions, such as those seen in humans, remains unclear. We aimed to elucidate the role of vitamin C treatment on generation and maintenance of iTregs from gulo knockout (Gulo-KO) mice as well as wild type (WT) mice, and in vitro and in vivo suppressive effects of V-iTregs on heart allograft rejection in either Gulo-KO or WT recipient mice. Conversion efficiency of iTregs was similar between C- and V-iTregs in both WT and Gulo-KO mice. V-iTregs from WT or Gulo-KO mice showed better in vitro Foxp3 stability than C-iTregs, although there was no difference between WT V-iTregs and Gulo-KO V-iTregs. Furthermore, V-iTregs from WT or Gulo-KO mice suppressed in vitro T cell proliferation better than C-iTregs. Heterotrophic heart transplantation from BALB/c mice to WT or vitamin C-deficient Gulo-KO C57BL/6J mice was performed following adoptive transfer of C- or V-iTregs. V-iTregs as well as C-iTregs prolonged heart allograft survival in WT and Gulo-KO mice. However, there was no difference between the C- and V-iTreg groups. Supplementation of low- or high-dose vitamin C did not induce significant changes in heart allograft survival in Gulo-KO recipients that had received V-iTregs. In conclusion, V-iTregs do not exert better suppressive effects on heart allograft survival than C-iTregs in either WT or vitamin C-deficient recipients.

Hyperbaric oxygen therapy to prevent central airway stenosis after lung transplantation.

BACKGROUND: Central airway stenosis (CAS) is a severe airway complication after lung transplantation associated with bronchial ischemia and necrosis. We sought to determine whether hyperbaric oxygen therapy (HBOT), an established treatment for tissue ischemia, attenuates post-transplant bronchial injury. METHODS: We performed a randomized, controlled trial comparing usual care with HBOT (2 atm absolute for 2 hours × 20 sessions) in subjects with extensive airway necrosis 4 weeks after transplantation. Endobronchial biopsies were collected at 4, 7, and 10 weeks after transplantation for a quantitative polymerase chain reaction. Coprimary outcomes were incidence of airway stenting and acute cellular rejection (ACR) at 1 year. RESULTS: The trial was stopped after enrolling 20 subjects (n = 10 per group) after a pre-planned interim analysis showed no difference between usual care and HBOT groups in stenting (both 40%), ACR (70% and 40%, respectively), or CAS (40% and 60%, respectively). Time to first stent placement (median [interquartile range]) was significantly shorter in the HBOT group (150 [73-150] vs 186 [167-206] days, p < 0.05). HIF gene expression was significantly increased in donor tissues at 4, 7, and 10 weeks after transplantation but was not altered by HBOT. Subjects who developed CAS or required stenting had significantly higher HMOX1 and VEGFA expression at 4 weeks (both p < 0.05). Subjects who developed ACR had significant FLT1, TIE2, and KDR expression at 4 weeks (all p < 0.05). CONCLUSIONS: Incidence of CAS is high after severe, established airway necrosis after transplantation. HBOT does not reduce CAS severity or stenting. Elevated HMOX1 and VEGFA expressions appear to associate with airway complications.

Thalidomide treatment prevents chronic graft rejection after aortic transplantation in rats - an experimental study.

Cardiac allograft vasculopathy (CAV) affects approximately 30% of cardiac transplant patients at 5 years post-transplantation. To date, there are few CAV treatment or prevention options, none of which are highly effective. The aim of the study was to investigate the effect of thalidomide on the development of CAV. The effect of thalidomide treatment on chronic rejection was assessed in rat orthotopic aortic transplants in allogeneic F344 or syngeneic Lew rats (n = 6 per group). Animals were left untreated or received thalidomide for 30 days post-transplant, and evidence of graft CAV was determined by histology (trichrome and immunohistochemistry) and intragraft cytokine measurements. Animals that received thalidomide treatment post-transplant showed markedly reduced luminal obliteration, with concomitant rescue of smooth muscle cells (SMCs) in the aortic media of grafts. Thalidomide counteracted neointimal hyperplasia by preventing dedifferentiation of vascular SMCs. Measurement of intragraft cytokine levels after thalidomide treatment revealed downregulation of matrix metalloproteinase 8 and monocyte chemotactic protein 1, cytokines involved in tissue remodelling and inflammation, respectively. Importantly, no negative side effects of thalidomide were observed. Thalidomide treatment prevents CAV development in a rodent model and is therefore potentially useful in clinical applications to prevent post-transplant heart rejection.

Diffuse alveolar hemorrhage induced by everolimus.

Pulmonary toxicity is a known complication of the proliferation signal inhibitor (PSI) sirolimus and consists of diverse entities such as interstitial pneumonitis, lymphocytic alveolitis, bronchiolitis obliterans with organizing pneumonia, and diffuse alveolar hemorrhage. Several cases of interstitial pneumonitis have also been reported with the more recently developed PSI everolimus. In this report, a case of diffuse alveolar hemorrhage attributed to everolimus is described. The patient presented with respiratory symptoms of insidious onset, ultimately resulting in severe respiratory failure characterized by high lactate dehydrogenase levels, patchy ground-glass infiltrates, and bloody BAL fluid with predominance of iron-loaded macrophages and monocytes. Withdrawal of the offending drug and temporary association of high-dose steroids resulted in a rapid recovery. Given that prompt drug discontinuation is potentially life saving, PSI-induced pulmonary toxicity should be considered in the differential diagnosis of patients treated with PSIs and presenting with respiratory symptoms or pulmonary lesions.

Evaluation of a topical cyclosporine A prodrug on corneal graft rejection in rats.

PURPOSE: To assess the efficacy of a topical cyclosporine A (CsA), water-soluble prodrug, for promoting the survival of allogenic rat corneal grafts after penetrating keratoplasty (PKP). METHODS: Corneas of Brown-Norway rats (donors) were transplanted to Lewis rats (recipients). Transplanted rats were divided in three treatment groups: group I (PBS) and group II (0.26% Debio088) received drops five times per day. Group III received a daily intramuscular CsA injection (10 mg/kg/day). Blood CsA concentrations were measured on days 2 and 14. On day 4, 10, 13 after PKP, grafts were scored for corneal transparency, edema and extent of neovascularization. An opacity score of greater than or equal to 3 was considered as a nonreversible graft rejection process. On day 14, the experimental eyes were processed for histology. RESULTS: On day 13, 12 of the 18 corneal transplants (67%) in group I showed irreversible graft rejection. Three of 18 transplants (19%) in group II and 5 of 16 transplants (28%) in group III showed irreversible graft rejection (p=0.013/p=0.019, OR=0.14/0.06 versus vehicle). Each mean clinical score for edema, opacity, and neovessels in group II were significantly lower than those of the grafts in group I (respectively p=0.010, p=0.013, p=0.024) and III except for neovessels (respectively p=0.002, p=0.001, p=0.057). Histology confirmed the clinical results. The mean CsA blood levels for groups II and III were, respectively 54+/-141 mug/l and 755+/-319 mug/l on day 2 and 14+/-34 mug/l and 1318+/-463 mug/l on day 14. CONCLUSIONS: Debio088 CsA prodrug drops given five times daily are as effective as intramuscular injection of 10 mg/kg/day for the prevention of acute corneal graft rejection in rats.

Osteoporosis after renal transplantation.

This study was performed to determine risk factors associated with osteoporosis that develops after renal transplantation. Sixty-five kidney graft recipients were included in this study. They were divided into four groups according to the time since transplantation: Group 1 (< 1 year; n = 26), group 2 (1-3 years; n = 16), group 3 (3-5 years; n = 12) and group 4 (> 5 years; n = 11). These groups were matched according to probable risk factors for osteoporosis, findings of serum biochemistry, biochemical markers of bone turnover and measurements of bone mineral density. One way ANOVA test and Kruskal-Wallis test were used for statistical analysis. Osteoporosis was found in 22 recipients (33.8%). There were significant differences in recipient age, cumulative steroid dose, and episodes of acute rejection between the four groups. Increasing age, cumulative steroid dose and episodes of acute rejection were found to be risk factors for osteoporosis in our study.

Osteoporosis after renal transplantation / Osteoporosis después del trasplante renal

This study was performed to determine risk factors associated with osteoporosis that develops after renal transplantation. Sixty-five kidney graft recipients were included in this study. They were divided into four groups according to the time since transplantation : Group 1 (< 1 year ; n = 26 ), group 2 (1 – 3 years ; n = 16), group 3 (3-5 years ; n = 12) and group 4 (> 5 years ; n = 11). These groups were matched according to probable risk factors for osteoporosis, findings of serum biochemistry, biochemical markers of bone turnover and measurements of bone mineral density. One way ANOVA test and Kruskal-Wallis test were used for statistical analysis. Osteoporosis was found in 22 recipients (33.8%). There were significant differences in recipient age, cumulative steroid dose, and episodes of acute rejection between the four groups. Increasing age, cumulative steroid dose and episodes of acute rejection were found to be risk factors for osteoporosis in our study (AU)

Este estudio tuvo como objetivo determinar factores de riesgo asociados a osteoporosis que se desarrolla después del trasplante renal. En este estudio se incluyeron 65 pacientes portadores de un trasplante renal. Se dividieron en 4 grupos de acuerdo al tiempo desde el trasplante: Grupo 1 (< 1 año; n = 26), grupo 2 (1-3 años; n = 16), grupo 3 (3 a 5 años = 12) y grupo 4 (> 5 años; n = 11). Todos los grupos se ajustaron de acuerdo a probables factores de riesgo de osteoporosis, marcadores bioquímicos, marcadores de recambio óseo y densidad mineral ósea. El análisis estadístico se realizó por medio de ANOVA y mediante el test Kruskal-Wallis. Se encontró osteoporosis en un total de 22 receptores de trasplante de riñón (33,8%). La edad de recepción del trasplante, la dosis acumulada de esteroides y los episodios de rechazo agudo de trasplante renal fueron estadísticamente significativos entre los cuatro grupos. El aumento de la edad, la dosis acumulada de esteroides y los episodios de rechazo agudo fueron factores de riesgo de osteoporosis en nuestro estudio (AU)

Candesartan cilexetil reduces graft arteriosclerosis in aortic transplantation model in rat.

To date established treatment of transplant arteriosclerosis is basically missing and there is a need for new therapeutic approaches. Angiotensin II (Ang II) and Ang II receptor type 1 (AT) are present in the vascular wall. Blocking of the AT1 receptor by pharmacological agents may inhibit damaging effects of Ang II on endothelial and smooth muscle cells. The purpose of the study was to evaluate the effect of the AT1 receptor blocker Candesartan cilexetil on the development of graft arteriosclerosis in a rat aortic transplant model. Two strain combinations were used for aortic transplantation: DA to PVG; and PVG to PVG. The animals received Candesartan cilexetil treatment (9.5 + 1.4 mg/kg/day) for 8 weeks. Candesartan cilexetil treatment reduced neointimal formation both in allografts (Qint 30.2 +/- 8.8% vs. 22.1 +/- 8.7%, P < 0.05) and in isografts (Qint 15.5 +/- 4.4% vs. 6.7 +/- 3.3%, P = 0.0001). Blocking of the AT1 receptor signalling by Candesartan cilexetil was also associated with a reduced expression of TGF-beta1. Macrophage infiltration was not affected by the treatment. Candesartan cilexetil treatment leads to reduced neointimal formation in aortic transplant. The positive effect of the drug might be partly explained by a reduction of TGF-beta1 expression in the grafts. Candesartan treatment may provide another possibility for prevention of transplant arteriosclerosis and chronic rejection.

Antiviral and immunomodulatory effects of desferrioxamine in cytomegalovirus-infected rat liver allografts with rejection.

BACKGROUND: Cytomegalovirus (CMV) infection is associated with acute and chronic allograft rejection. We have recently shown that rat CMV increases portal inflammation and bile duct destruction in a model of rat liver allograft rejection. Desferrioxamine (DFO), an iron chelator and antioxidant, has recently been demonstrated to have antiviral as well as immunomodulatory effects in vitro. We therefore investigated whether DFO inhibits (a) CMV infection and (b) graft destruction in our rat model. METHOD: One day after liver transplantation, PVG (RT1c) into BN(RT1n), the rats were infected with rat CMV (RCMV, Maastricht strain; 10(5) plaque-forming units i.p.). The effects of 100 mg/kg body weight and 200 mg/kg body weight DFO were examined. RESULTS: In the untreated group, the grafts were uniformly RCMV culture-positive. In the group receiving 200 mg/kg DFO, RCMV replication was effectively inhibited. Inflammatory response in the graft, and especially the number of macrophages, was significantly reduced by DFO. Portal inflammation and bile duct destruction were also significantly reduced. In the untreated group, the bile duct epithelial cells were found to be strongly positive for tumor necrosis factor-alpha and this expression was clearly decreased by DFO. In addition, DFO significantly inhibited vascular cell adhesion molecule-1 expression on sinusoidal endothelial cells. CONCLUSIONS: Our in vivo transplant study strongly supports the inhibitory effects of metal chelators on CMV infection and their possible usefulness in the treatment of CMV-induced pathogenic changes.