Recipient Rats Research Articles

Acute rejection after kidney transplantation promotes graft fibrosis with elevated adenosine level in rat.

AimsChronic allograft nephropathy is a worldwide issue with the major feature of progressive allograft fibrosis, eventually ending with graft loss. Adenosine has been demonstrated to play an important role in process of fibrosis. Our study aimed to investigate the relationship between adenosine and fibrosis in renal allograft acute rejection in rat.Materials and methodsWistar rats and SD rats were selected as experimental animals. Our study designed two groups. In the allograft transplantation group, kidneys of Wistar rats were orthotopically transplanted into SD rat recipients, the same species but not genetically identical, to induce acute rejection. Kidney transplantations of SD rats to SD rats which were genetically identical were served as the control. We established rat models and detected a series of indicators. All data were analyzed statistically. P<0.05 was considered statistically significant.ResultsCompared with the control group, levels of adenosine increased significantly in the allograft transplantation group, in which acute rejection was induced (P<0.05). Progressive allograft fibrosis as well as collagen deposition were observed.ConclusionsThese findings suggested that level of adenosine was upregulated in acute rejection after kidney allograft transplantation in rat. Acute rejection may promote renal allograft fibrosis via the adenosine signaling pathways.

CLINICAL ANd IMMuNOLOGICAL CHARACTERISTICS POSTOPERATIVE PERIOd AT HEMIFACIAL ALLOGRAFTS AVASCuLAR SKIN FLAP

In an experiment on rats Wistar family and dark Agouti immunological status of recipients has been studied with facial allograft skin flap in the early and late postoperative periods. The evaluation of the state of the transplant and the general condition of the recipient rats after surgery immunosuppressive therapy.

Calcium Concentration in Culture Medium as a Nondestructive and Rapid Marker of Osteogenesis

Artificial bones made of β-tricalcium phosphate (β-TCP) combined with bone marrow-derived mesenchymal stromal cells (BM-MSCs) are used for effective reconstruction of bone defects caused by genetic defects, traumatic injury, or surgical resection of bone tumors. However, the selection of constructs with high osteogenic potential before implantation is challenging. The purpose of this study was to determine whether the calcium concentration in BM-MSC culture medium can be used as a nondestructive and simple osteogenic marker for selecting tissue-engineered grafts constructed using β-TCP and BM-MSCs. We prepared three cell passages of BM-MSCs derived from three 7-week-old, male Fischer 344 rats; the cells were cultured in osteoinductive medium in the presence of β-TCP for 15 days. The medium was replaced with fresh medium on day 1 in culture and subsequently changed every 48 h; it was collected for measurement of osteocalcin secretion and calcium concentration by enzyme-linked immunosorbent assay and X-ray fluorescence spectrometry, respectively. After cultivation, the constructs were implanted subcutaneously into the backs of recipient rats. Four weeks after implantation, the alkaline phosphatase (ALP) activity and osteocalcin content of the constructs were measured. A strong inverse correlation was observed between the calcium concentration in the medium and the ALP activity and osteocalcin content of the constructs, with Pearson's correlation coefficients of 0.92 and 0.90, respectively. These results indicate that tissue-engineered bone with high osteogenic ability can be selected before implantation based on low calcium content of the culture medium, resulting in successful bone formation after implantation. This nondestructive, simple method shows great promise for assessing the osteogenic ability of tissue-engineered bone.

Exogenous vascular endothelial growth factor delivery prior to endothelial precursor cell transplantation in orthotopic liver transplantation-induced hepatic ischemia/reperfusion injury.

Vascular endothelial growth factor (VEGF) promotes angiogenesis in vivo. We hypothesized that exogenous delivery of VEGF prior to bone marrow-derived endothelial precursor cell (EPC) transplantation may improve orthotopic liver transplantation (OLT)-induced hepatic ischemia/reperfusion injury (HIRI). OLT between Sprague Dawley donor rats and inbred LEW Wistar recipient rats was performed in 6 experimental groups to comparatively assess the effects of the VEGF gene: an untreated normal control group, a surgical control group, a liposomal control group, a VEGF group receiving only the liposome-encapsulated VEGF plasmid, an EPC group receiving only EPCs, and an EPC+VEGF group receiving the liposome-encapsulated VEGF plasmid followed by EPCs. VEGF plasmid delivery to liver tissue, endogenous VEGF, and vascular endothelial growth factor receptor (VEGFR) expression, liver transaminase levels, hepatocellular injury levels, apoptosis, apoptotic biomarkers, hepatotrophic mitogens, angiogenesis, and nitric oxide synthase (NOS) activity were assayed after OLT. Exogenous VEGF gene delivery prior to EPC transplantation significantly increased endogenous VEGF and VEGFR expression, significantly reduced liver transaminase levels, significantly reduced hepatocellular injury levels, significantly reduced hepatic apoptosis levels, and significantly reduced several apoptotic biomarkers (ie, B cell lymphoma 2-associated X protein/B cell lymphoma 2 ratio, caspase 3 activity, and heat shock protein 70 expression) in post-OLT-induced HIRI. Moreover, VEGF gene delivery prior to EPC transplantation significantly increased hepatotrophic mitogen expression (ie, epidermal growth factor, heparin-binding epidermal growth factor-like growth factor, hepatocyte growth factor, and transforming growth factor α), angiogenesis, and NOS activity in post-OLT-induced HIRI. In conclusion, exogenous liposomal delivery of the VEGF gene prior to bone marrow-derived EPC transplantation may be an effective strategy in decreasing OLT-induced HIRI. Liver Transplantation 23 804-812 2017 AASLD.

The intrauterine environment affects learning ability of Tokai high avoider rat offspring derived using cryopreservation and embryo transfer-mediated reproduction

Embryo transfer (ET) to recipient female animals is a useful technique in biological and experimental animal studies. While cryopreservation of two-cell stage rat embryos and ET to recipient rats are currently well-defined, it is unknown whether these artificial reproductive techniques and maternal factors affect offspring phenotype, particularly higher brain functions. Therefore, we assessed the effects of cryopreservation, ET, and maternal care on learning behaviour of the offspring, using Tokai high avoider (THA) rats that have a high learning ability phenotype. We found that the high learning ability of THA rat offspring was not replicated following ET to surrogate Wistar rats with a low-avoidance phenotype. Additionally, the characteristic phenotype of offspring obtained through mating of ET-derived rats was similar to that of THA rats. A postnatal cross-fostering investigation with the offspring of Wistar and THA rats showed that maternal behaviour, including postnatal care and lactation traits, did not differ between the dams of low-avoidance Wistar rats and THA rats; therefore, learning behaviour was retained in both Wistar and THA rat offspring. We conclude that the offspring phenotype, although unchanged, has an imperceptible effect on the learning ability of ET-derived THA rats through the intrauterine environment of the recipient.

A cross-circulated bicephalic model of head transplantation.

A successful cephalosomatic anastomosis ("head transplant") requires, among others, the ability to control long-term immune rejection and avoidance of ischemic events during the head transference phase. We developed a bicephalic model of head transplantation to study these aspects. The thoracic aorta and superior vena cava of a donor rat were anastomosed with the carotid artery and extracorporeal veins of a recipient rat by vascular grafts. Before thoracotomy in the donor rat, the axillary artery and vein of the donor were connected to the carotid and the extracranial vein of the third rat through a silicone tube. The silicone tube was passed through a peristaltic pump to ensure donor brain tissue blood supply. There is no ischemia reperfusion injury in donor brain tissue analyzed by electroencephalogram. Postoperative donor has pain reflex and corneal reflex. Peristaltic pump application can guarantee the blood supply of donor brain tissue per unit time, while the application of temperature change device to the silicone tube can protect the brain tissue hypothermia, postoperative experimental data show that there is no brain tissue ischemia during the whole operation. The application of vascular grafting can also provide the possibility of long-term survival of the model.

Microbiota Is Involved in Post-resection Adaptation in Humans with Short Bowel Syndrome.

Short bowel syndrome (SBS) is characterized by severe intestinal malabsorption following restrictive surgery. The objective of this study was to determine the functional contribution of SBS-microbiota after resection. It is well-known that SBS-microbiota displayed specific features with a prevalence of Lactobacillus, a low amount of some anaerobic microbes (Clostridium leptum) and an accumulation of fecal lactate in some patients. Patients with jejuno-colonic anastomosis were stratified according to the presence of lactate in their feces and, we observe that the lactate-producing bacteria were predominant in the sub-group of patients accumulating fecal lactate. One case of D-encephalopathy crisis occurred when the D-lactate isoform accumulated in the feces and plasma bicarbonate levels decreased. The fecal sample at the time of the encephalopathy was transferred to germ free rats (SBS-H rats). The SBS-H microbiota conserved some characteristics of the SBS donnor, predominated by lactate-producing bacteria (mainly Lactobacillus), a low level of lactate-consuming bacteria and undetectable C. leptum. However, lactate did not accumulate in feces of recipient rats and the D-encephalopathy was not reproduced in SBS-H rats. This suggests that the intact small bowel of the recipient rats protected them from lactate accumulation and that D-lactate encephalopathy can occur only in the absence of small intestine. After fecal transfer, we also show that gnotobiotic rats exhibited high levels of circulating GLP-1 and ghrelin, two hormones that are known to be induced in SBS patients. Therefore, the microbiota of SBS is a reservoir of biological signals involved in post-resection adaptation.

Bone Marrow Transfer from Rats Fed Low or High Salt Diets Does Not Influence Salt‐Sensitive Blood Pressure and Kidney Disease in Dahl SS Recipient Rats

Increasing evidence indicates a role for the immune system in the development of hypertension and renal disease. Studies in our laboratory have demonstrated that pharmacological or genetic inhibition of adaptive immunity attenuates salt‐sensitive hypertension in the Dahl SS rat. Specifically, Dahl SS rats with a mutation in CD247 (SSCD247−/−), a gene encoding the CD3 zeta chain, lack CD3+ T‐cells and have a marked attenuation of salt‐sensitive hypertension and renal damage. The present study was designed to investigate the potential role of memory cells in the bone marrow in the development of salt‐sensitive disease. Age‐matched Dahl SS rats were kept on either a low salt (0.4% NaCl) or a high salt (4.0% NaCl) diet for 3 weeks starting at 3 weeks of age. Bone marrow from these SS rats was then transferred into age‐matched, SSCD247−/− rats (n=4 low salt bone marrow; n=5 high salt bone marrow) that underwent total body irradiation (TBI) at a dose of 11 Gy and a rate of 1.83 Gy/min. The recipient SSCD247−/− rats that underwent TBI had been maintained throughout life on the low salt diet and received bone marrow from SS rats fed the low (LSBM) or high salt (HSBM) diet. Any T cells reconstituted in the SSCD247−/− rats which underwent TBI therefore arose from the donor SS. After two weeks of recovery, the LSBM and HSBM rats were instrumented for blood pressure measurement by telemetry. While maintained on a low salt diet, there was no difference in the MAP or urine albumin excretion (Ualb) rate in the LSBM (108±2 mmHg and 0.8±0.3 mg/day) or HSBM rats (111±4mmHg and 2.4±1.6 mg/day). The rats were then switched to a high salt diet and followed for 7 days. When the rats were switched to a high salt diet, MAP and Ualb tended to increase compared to baseline in the LSBM group (127±5 mmHg and 41.4±13.5 mg/day) and MAP but not Ualb significantly increased in the HSBM group (129±6 mmHg and 60.9±27.7 mg/day), but there were no significant differences between groups after 7 days. A subsequent flow cytometry analysis demonstrated reconstitution of T‐lymphocyte (CD45+/CD3+), helper T cell (CD4+), cytotoxic T cell (CD8+), and T‐memory cell (CD44h) populations, but there were no significant differences between the two groups at this time in the any of the tissues collected (PBMCs, spleen, bone marrow, and kidneys). Though significant differences were not detected between groups in the time frame of this experiment, we plan to repeat this experiment for an extended high salt period as previous work has demonstrated the effects of immune cells on hypertension and renal damage in Dahl SS rats typically begins at approximately Day 14 of high salt.Support or Funding InformationSupported by DK96859, HL116264, and 15SFRN2391002

Transplantation of CD51+ Stem Leydig Cells: A New Strategy for the Treatment of Testosterone Deficiency.

Stem Leydig cell (SLC) transplantation could provide a new strategy for treating the testosterone deficiency. Our previous study demonstrated that CD51 (also called integrin αv) might be a putative cell surface marker for SLCs, but the physiological function and efficacy of CD51+ SLCs treatment remain unclear. Here, we explore the potential therapeutic benefits of CD51+ SLCs transplantation and whether these transplanted cells can be regulated by the hypothalamic-pituitary-gonadal (HPG) axis. CD51+ cells were isolated from the testes of 12-weeks-old C57BL/6 mice, and we showed that such cells expressed SLC markers and that they were capable of self-renewal, extensive proliferation, and differentiation into multiple mesenchymal cell lineages and LCs in vitro. As a specific cytotoxin that eliminates Leydig cells (LCs) in adult rats, ethane dimethanesulfonate (EDS) was used to ablate LCs before the SLC transplantation. After being transplanted into the testes of EDS-treated rats, the CD51+ cells differentiated into mature LCs, and the recipient rats showed a partial recovery of testosterone production and spermatogenesis. Notably, a testosterone analysis revealed a circadian rhythm of testosterone secretion in cell-transplanted rats, and these testosterone secretions could be suppressed by decapeptyl (a luteinizing hormone-releasing hormone agonist), suggesting that the transplanted cells might be regulated by the HPG axis. This study is the first to demonstrate that CD51+ SLCs can restore the neuroendocrine regulation of testicular function by physiologically recovering the expected episodic changes in diurnal testosterone serum levels and that SLC transplantation may provide a new tool for the studies of testosterone deficiency treatment. Stem Cells 2017;35:1222-1232.

Prefabrication of Vascularized Allogenic Bone Graft in a Rat by Implanting a Flow-Through Vascular Pedicle and Basic Fibroblast Growth Factor Containing Hydroxyapatite/Collagen Composite.

Background Basic fibroblast growth factor (bFGF) is known to stimulate bone formation and angiogenesis. Hydroxyapatite/collagen composite (HAp/Col) is also known to have very strong bone conductive activity. In this study, prefabrication of vascularized allogenic bone (allo-bone) graft was attempted in recipients by implanting vascular bundles from recipients into the transplanted allo-bone graft. Furthermore, the effect of bFGF-containing HAp/Col on the prefabricated vascularized allo-bone graft was investigated. Methods In this study, 32 Sprague-Dawley rats were used as donors, and bone grafts were collected from their femora. Thirty-two Wistar rats (recipients) were divided into four groups, and the allo-bone grafts were transplanted into the thigh region. In the experimental groups, one or both of the flow-through saphenous vascular bundles and 100-μg bFGF-containing HAp/Col were implanted into the medullary cavity of the allo-bone grafts. In the control group, neither was implanted. These rats were sacrificed at 4 weeks after transplantation, and bone formation, angiogenesis, and bone resorption in the transplanted allo-bone grafts were evaluated histologically and genetically. Results Bone formation and angiogenesis in the transplanted allo-bone graft were effectively stimulated by implanting vascular bundles or bFGF-containing HAp/Col on both histological and genetic evaluations compared with the control group. The most significant stimulation was observed in the group in which both were implanted. Bone resorption was not stimulated in any group. Conclusion By implanting a flow-through vascular bundle and bFGF-containing HAp/Col, an ideal vascularized allo-bone graft that had high bone formative and angiogenetic activities and did not stimulate bone resorptive activity was prefabricated.

Granulocyte colony-stimulating factor enhances the therapeutic efficacy of bone marrow mesenchymal stem cell transplantation in rats with experimental acute pancreatitis.

IntroductionAcute pancreatitis (AP) is one of the most common diseases involving necrotic inflammation. Bone marrow mesenchymal stem cells (BMMSCs) have the potential of multi-directional differentiation and self-renewal for tissue repair. It remains less clear if granulocyte colony-stimulating factor (G-CSF) can improve the therapeutic effect of BMMSC transplant in AP. Therefore, we explored this issue in a rat model of experimental AP.ResultsTransplanted PKH26-positive BMMSCs were present in the injured pancreatic tissue, with some cells co-expressed pancreatic cellular markers, including Pax-4, Ngn3 and Nkx-6. Pathological, biochemical and serological data suggested an improvement in histological and functional recovery in these animals relative to control. Overall, the AP model rats received BMMSCs and G-CSF co-treatment showed better recovery in terms of tissue regeneration and blood biochemical levels relative to other groups.Materials and MethodsBMMSCs from donor rats were labeled with the fluorescent dye PKH26 and transfused into recipient rats with AP induced by L-arginine. The animals were divided into a control group, and groups treated with BMMSCs, G-CSF, and BMMSCs together with G-CSF. Therapeutic effects were evaluated histologically with immunohistochemistry and immunofluorescence, together with biochemical measurement of pancreatic markers.ConclusionG-CSF therapy with BMMSC transplantation improves histological and functional outcomes in rats with experimental AP.

Hyperbaric Oxygenation Protects Against Ischemia-Reperfusion Injury in Transplanted Rat Kidneys by Triggering Autophagy and Inhibiting Inflammatory Response.

BACKGROUND Ischemia-reperfusion injury (IRI) is a clinically common pathologic process defined as the inability to improve neuronal function. This study aimed to investigate the pathological mechanism of IRI and to explore effects of hyperbaric oxygenation (HBO) on autophagy and inflammatory response in IRI. MATERIAL AND METHODS Ninety Sprague-Dawley (SD) rats were randomly divided into a Sham group, a kidney transplant group (Trans), and a kidney transplant plus HBO treatment group (Trans+HBO). The kidney was harvested from the donor and transplanted to recipient rats according to a previously reported study. Rats were anesthetized using pentobarbital-natrium, and the kidney was resected and fixed in 4% paraformaldehyde. Serum creatinine (Scr) was detected using an automatic biochemical analyzer. The interleukin-6 (IL-6) level was assessed using enzyme-linked immunosorbent assay (ELISA). LC-3 was examined using indirect immunofluorescence assay and immunochemistry assay. LC-3 mRNA levels were analyzed using real-time PCR (RT-PCR). RESULTS The kidney transplant IRI model was successfully established. Scr and IL-6 levels were significantly increased in the Trans group (P<0.05). HBO significantly enhanced Scr and IL-6 levels. Scr was positively correlated with IL-6 levels (r-0.607, P<0.05). HBO increased LC-3 protein and mRNA expression in kidney-transplanted rats compared to the Sham and Trans group (P<0.05). Moreover, immunofluorescence assay also showed that LC-3 protein mainly distributes along renal tubular epithelial cells in a linear manner. CONCLUSIONS Autophagy dysfunction and inflammatory response after renal transplantation play important roles in processes of IRI. HBO treatment protects against the renal injury of IRI in renal tissues at the early stage, which may be triggered by the IL-6 pathway.

Transfusion of Plasma Collected at Late Phase after Preconditioning Reduces Myocardial Infarct Size Induced by Ischemia-reperfusion in Rats In vivo.

Background:Plasma transfusion is a common clinical practice. Remote ischemic preconditioning (RIPC) protects organs against ischemia-reperfusion (IR) injury. Whether preconditioned plasma (PP), collected at late phase after RIPC, could protect organs against IR injury in vivo is unknown. This study explored whether transfusion of PP could reduce myocardial infarct size (IS) after IR in rat in vivo.Methods:Eighty Lewis rats were randomized to eight groups (n = 10 for each group). Two groups of plasma donor rats donated plasma at 48 h after transient limb ischemia (PP) or control protocol (nonpreconditioned plasma [NPP]). Six groups of recipient rats received normal saline (NS; NS-IR 1, and NS-IR 24 groups), NPP (NPP-IR 1 and NPP-IR 24 groups), or PP (PP-IR 1 and PP-IR 24 groups) at one or 24 h before myocardial IR. Myocardial IR consisted of 30-min left anterior descending (LAD) coronary artery occlusion and 180-min reperfusion. The area at risk (AAR) and infarct area were determined by double-staining with Evans blue and triphenyltetrazolium chloride. IS was calculated by infarct area divided by AAR. This was a 3 × 2 factorial design study, and factorial analysis was used to evaluate the data. If an interaction between the fluid and transfusion time existed, one-way analysis of variance with Bonferroni correction for multiple comparisons was used to analyze the single effects of fluid type when the transfusion time was fixed.Results:IS in the NPP-IR 1 and PP-IR 1 groups was smaller than in the NS-IR 1 group (F = 6.838, P = 0.005; NPP-IR 1: 57 ± 8% vs. NS-IR1: 68 ± 6%, t = 2.843, P = 0.020; PP-IR 1: 56 ± 8% vs. NS-IR 1: 68 ± 6%, t = 3.102, P = 0.009), but no significant difference was detected between the NPP-IR 1 and PP-IR 1 groups (57 ± 8% vs. 56 ± 8%, t = 0.069, P = 1.000). IS in the NPP-IR 24 and PP-IR 24 groups was smaller than in the NS-IR 24 group (F = 24.796, P < 0.001; NPP-IR 24: 56% ± 7% vs. NS-IR 24: 68 ± 7%, t = 3.102, P = 0.026; PP-IR 24: 40 ± 9% vs. NS-IR 24: 68 ± 7%, t = 7.237, P < 0.001); IS in the PP-IR 24 group was smaller than in the NPP-IR 24 group (40 ± 9% vs. 56 ± 7%, t = 4.135, P = 0.002).Conclusion:Transfusion of PP collected at late phase after remote ischemic preconditioning could reduce IS, suggesting that late-phase cardioprotection was transferable in vivo.

Microsurgical tunica albuginea transplantation in an animal model.

Several andrological diseases require surgical repair or reconstruction of tunica albuginea, which envelops the corpora cavernosa penis. Despite intense research efforts involving a variety of biological materials, such as skin, muscle aponeurosis, human dura mater, tunica vaginalis, and pericardium, engineered tunica albuginea suitable for graft use is yet to be obtained. The study investigates microsurgical tunica albuginea allotransplantation in an animal model with the purpose of creation of an organ-specific tissue bank to store penile tissue, from cadaveric donors and male-to-female trans-sexual surgery, for allogeneic transplantation. Materials were tunica albuginea tissue explanted from 15 donor rats, cryopreserved at −80°C, gamma-irradiated, and implanted in 15 recipient rats, of which three rats were used as controls. Penile grafts were explanted at different time intervals; after macroscopic evaluation of the organ, the grafts were processed to morphological, histochemical, and immunohistochemical examinations by light microscopy. Detection of pro-inflammatory cytokines was also performed. Examination of the tunica albuginea allografts collected 1, 3, or 6 months after surgery and of control tunica albuginea fragments showed that tunica albuginea implants achieved biointegration with adjacent tissue at all-time points. The integration of cryopreserved rat tunica albuginea allografts, documented by our study, encourages the exploration of tunica albuginea allotransplantation in humans. In conclusion, the effectiveness and reliability of the tunica albuginea conditioning protocol described here suggest the feasibility of setting up a tunica albuginea bank as a further tissue bank.

Adipose-derived mesenchymal stem cells suppress of acute rejection in small bowel transplantation.

Background/Aims:Adipose-derived mesenchymal stem cells (ADSCs) possess immunosuppressive activity and hold promise in autologous cell-based therapies. The aim of this study was to determine whether autologous ADSCs can improve outcomes in the rat small bowel transplantation (SBT) model.Materials and Methods:Allogeneic SBT followed by implantation of autologous ADSCs through the penile vein was conducted in Brown-Norway (BN) donor rats with Lewis (LEW) recipient rats infused with phosphate buffered solution as the control. Allograft and recipient peripheral blood were obtained. We assessed histopathology, apoptosis, cytokines, and regulatory T cells (Tregs). One-way analysis of variance was applied to assess the significance of the data.Results:It was found that ADSCs significantly reduced acute rejection and improved the allograft's survival rate. In addition, there were significantly fewer apoptotic cells in allograft mucosae in the ADSC group in comparison with the control group. Furthermore, levels of interleukin (IL)-10 and transforming growth factor-β1 were significantly elevated, whereas those of IL-2 and IL-17 levels were significantly reduced in the ADSC group when compared to the control group. Moreover, flow cytometry analysis revealed that there were significantly more peripheral Tregs after the infusion of ADSCs.Conclusions:These results demonstrate that implanted autologous ADSCs improve allogeneic small bowel allograft outcomes by attenuating the acute rejection and reducing inflammatory responses.

AS2553627, a novel JAK inhibitor, prevents chronic rejection in rat cardiac allografts

Janus family kinases (JAKs) are essential molecules for cytokine responses and attractive targets for the treatment of transplant rejection and autoimmune diseases. Several JAK inhibitors have shown demonstrable effects on acute rejection in experimental cardiac transplant models. However, little is known about the potential benefits of JAK inhibitors on chronic rejection outcomes such as vasculopathy and fibrosis. Here, we examined the pharmacological profile of a novel JAK inhibitor, AS2553627, and explored its therapeutic potential in chronic rejection as well as acute rejection in a rat cardiac transplant model. AS2553627 potently inhibited JAK kinases but showed no inhibition of other kinases, including TCR-associated molecules. The compound also suppressed proliferation of IL-2 stimulated human and rat T cells. In a rat cardiac transplant model, oral administration of AS2553627 alone or co-administration with a sub-therapeutic dose of tacrolimus effectively prolonged cardiac allograft survival, suggesting the efficacy in treating acute rejection. To evaluate the effect on chronic rejection, recipient rats were administered a therapeutic dose of tacrolimus for 90 days. In combination with tacrolimus, AS2553627 significantly reduced cardiac allograft vasculopathy and fibrosis that tacrolimus alone did not inhibit. AS2553627 at the effective dose in rat transplantation models did not significantly reduce reticulocyte counts in peripheral whole blood after in vivo erythropoietin administration, indicating a low risk for anemia. These results suggest that AS2553627 may be a therapeutic candidate for the prevention of not only acute but also chronic rejection in cardiac transplantation.

Platelets from Fresh and Cold-Stored Whole Blood Contribute to Clot Formation after Transfusion in Rats with Acute Traumatic Coagulopathy

Background: The hemostatic and platelet functions of fresh whole blood (FWB) are well preserved when stored at 4°C for 14 days (human) or 7 days (rats). Resuscitation of either FWB or whole blood stored for 7-days at 4°C (SWB) in rats with acute traumatic coagulopathy (ATC) induced by polytrauma and hemorrhage (T/H), shows identical correction of hemodynamic and metabolic function, as well as the equivalent impact on platelet aggregation in vitro. Platelet hemostatic function is influenced by platelet number, aggregation, and platelet-leukocyte interactions. Therefore, the objective of this study is to identify the in-vivo fate and activity of platelets from FWB and SWB, and determine whether transfused platelets contribute to clot formation in tissue injury after transfusion.Method: Isoflurane anesthetized Sprague-Dawley rats underwent polytrauma, followed by 40% hemorrhage. The rats were resuscitated (20% of bled volume) 1hr after trauma using either FWB or SWB (n=5 each) collected from green fluorescence (GFP) donor rats. SWB was kept in mini-blood-bag and refrigerated at 40C for 7 days, and warmed up to 370C prior to transfusion. Sham rats had no trauma, but underwent 20% blood replacement by FWB or SWB (n=4 each). Immediately after transfusion, a liver incision was made, followed by the measurement of kidney bleeding time (both standardized incisions was made by a Surgicutt adult template device). The incisional liver sample was taken 10min after injury for immunohistochemistry stained for CD61 (platelets) and GFP. Blood samples taken from donor rats (FWB and SWB) and recipient rats at baseline, immediately before resuscitation, and 0min and 10min after transfusion were analyzed by flow cytometry using CD42d, CD45, and CD62P antibodies for defining platelets, leukocytes and activated platelets respectively. Lactadherin was used to detect phosphatidylserine (PS). Platelet-leukocyte aggregates were defined as CD42d+/CD45+. The transfused and native platelet or leukocyte was differentiated by GFP signal.Results: GFP signal intensity was equally expressed in platelets derived from either FWB or SWB. Storage at 4°C led to a significant increase in number of platelets expressing CD62P (76±2% vs. 11±4%) and PS (8.6±0.7% vs. 1.1±0.4%) as compared to FWB. SWB also showed a significant rise in intensity, but not percentage, of platelet-leukocyte aggregates (45781±6235 vs. 10978±2345 MFI). After transfusion, recipient rats showed a significant elevation in the percentage of GFP+ platelets after transfusion of FWB as compared to SWB (Sham:13.0±1.0% vs. 4.9±0.4%; T/H: 17.0±0.8% vs. 6.8±0.%). Similarly, GFP+ leukocytes aggregates from FWB were three times higher than SWB (Sham: 6.15±0.5% vs. 1.9±0.5%; T/H: 4.4±0.4% vs. 1.2±0.2%). There was greater percentage of GFP+ platelet-leukocyte aggregates in both T/H and sham rats transfused with SWB than FWB (Sham: 11.7±3.3% vs. 33.8±2.3%; T/H: 9.8±1.6% vs. 47.2±5.1%). Transfusion with SWB led to a significant increase in percentage of activated GFP+ platelets in T/H rats as compared to FWB (30.0±2.7% vs. 2.5±0.5%). However, the activity of native platelets was not significantly different between SWB and FWB in T/H rats after transfusion (3.9±1.2% vs. 3.7±0.3%). The kidney bleeding time was not significantly different in T/H rats receiving FWB and SWB (131±4 vs.127±7 seconds) under equivalent mean arterial blood pressure (82±7 vs 85±9 mmHg). The clot that formed at the site of liver incision was identified by platelet aggregates stained by the CD61 antibody. Using co-localization of CD61 and GFP, we found that the platelets from both FWB and SWB equivalently incorporated into the clot at incisional site.Conclusion: The platelets from SWB are higher in platelet activation state, clearance rate and platelet-leukocyte aggregates than FWB after transfusion in both sham rats and rats with polytrauma and hemorrhage. However, platelets from both fresh and cold-stored whole blood contribute to hemostasis of tissue injury after transfusion. This study suggests that cold-stored whole blood is an alternative resource to treat trauma patients for restoration of hemostatic function. Future study is necessary to optimize the storage of whole blood to prolong the platelet survival rate and optimize hemostatic function. This project was funded by US Army Medical Research and Material Command. DisclosuresNo relevant conflicts of interest to declare.

Plasma microRNAs Are Potential Biomarkers of Acute Rejection After Hindlimb Transplantation in Rats.

BackgroundThe development of effective immunosuppressive regimens has resulted in many cases of successful hand transplantation. Visual skin inspection and histological evaluation are used to assess the rejection of hand transplants, but these methods are largely subjective. In this study, we aimed to determine the potential of microRNAs (miRNAs) as biomarkers for acute rejection in vascularized composite allotransplants.MethodsIn allograft group, 7 male Brown-Norway rats (RT1n) were used as donors and 13 male Lewis rats (RT1l) were used as recipients. In control group, 8 Lewis rats were used as donors and recipients. The hindlimbs of donor rats were transplanted orthotopically to recipient rats. Skin changes were noted daily. Skin biopsies were obtained from 5 recipients and evaluated histologically. Plasma samples were obtained from the other 8 recipients before transplant and 7, 10, and 14 days posttransplant and used to measure miRNA expression.ResultsSkin changes occurred at a mean of 11.0 days posttransplant. Rejection in most skin biopsies taken 7 and 10 days posttransplant was histologically classified as grade 0, whereas that in most biopsies taken 14 days posttransplant was classified as grade 3. We found that expression of miRNA-146a and miRNA-155 was significantly upregulated at 10 and 14 days posttransplant compared with that at 7 days posttransplant. In control group, there were no significant changes in plasma miRNAs expressions.ConclusionsThe upregulation of plasma miRNA-146a and miRNA-155 was detected before the histological evaluation methods could diagnose complete rejection in the rat hindlimb transplantation model. Plasma miRNA-146a and miRNA-155 may be potential biomarkers of acute rejection after vascularized composite allotransplantation.

Magnetic Resonance Imaging of Cardiac Strain Pattern Following Transplantation of Human Tissue Engineered Heart Muscles.

The use of tissue engineering approaches in combination with exogenously produced cardiomyocytes offers the potential to restore contractile function after myocardial injury. However, current techniques assessing changes in global cardiac performance after such treatments are plagued by relatively low detection ability. Since the treatment is locally performed, this detection could be improved by myocardial strain imaging that measures regional contractility. Tissue engineered heart muscles (EHMs) were generated by casting human embryonic stem cell-derived cardiomyocytes with collagen in preformed molds. EHMs were transplanted (n=12) to cover infarct and border zones of recipient rat hearts 1 month after ischemia reperfusion injury. A control group (n=10) received only sham placement of sutures without EHMs. To assess the efficacy of EHMs, magnetic resonance imaging and ultrasound-based strain imaging were performed before and 4 weeks after transplantation. In addition to strain imaging, global cardiac performance was estimated from cardiac magnetic resonance imaging. Although no significant differences were found for global changes in left ventricular ejection fraction (control -9.6±1.3% versus EHM -6.2±1.9%; P=0.17), regional myocardial strain from tagged magnetic resonance imaging was able to detect preserved systolic function in EHM-treated animals compared with control (control 4.4±1.0% versus EHM 1.0±0.6%; P=0.04). However, ultrasound-based strain failed to detect any significant change (control 2.1±3.0% versus EHM 6.3±2.9%; P=0.46). This study highlights the feasibility of using cardiac strain from tagged magnetic resonance imaging to assess functional changes in rat models following localized regenerative therapies, which may not be detected by conventional measures of global systolic performance.

Prolongation of kidney allograft survival regulated by indoleamine 2, 3-dioxygenase in immature dendritic cells generated from recipient type bone marrow progenitors.

Immature dendritic cells (iDCs) are bone marrow-derived professional antigen-presenting cells, exhibit very low levels of the co-stimulatory molecules CD80 (B7-1), CD86 (B7-2), and CD40 and major histocompatibility complex (MHC) class II and play a critical role in triggering antigen-specific immunotolerance. The enzyme indoleamine 2, 3-dioxygenase (IDO) is a cytosolic tryptophan catabolism rate-limiting step enzyme. IDO secreted by DCs shows an association with the suppression of T-cell responses and promotion of tolerance. In this study, BN rat recipients were pre-injected with donor renal alloantigen-treated recipient iDCs before kidney transplantation. The renal allograft exhibited a lighter renal rejection response, prolonged graft survival time, and an increasing content of CD4+CD25+Foxp3+ regulatory T cells (Tregs). Additionally, up-regulated secretion of Th2 cytokines were found in recipient sera post-transplantation. Transfection of si-IDO1 RNA into renal-antigen-treated recipient iDCs reversed these changes, which suggested that IDO channel signaling may be involved in iDC-induced allograft immunotolerance. These results suggested that iDC-induced and IDO-mediated allograft immunotolerance might be a potentially feasible tactic to prolong allograft survival, in addition to immunosuppressive drugs.