Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and axonal fusion

Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration.Furthermore,such peripheral nerve allografts undergo immunological rejection by the host immune system.In contrast,peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks,reduced immune responses,and many axons do not undergo Wallerian degeneration.The relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this study.We hypothesized that polyethylene glycol might have some immune-protective effects,but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral recovery.We examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal fusion.Ablation-type sciatic nerve injuries in outbred Sprague–Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts,but peripheral nerve allografts were loose-sutured(loose-sutured polyethylene glycol)with an intentional gap of 1–2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host axons.Similar to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts,animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days postoperatively.Other morphological signs of rejection,such as collapsed Schwann cell basal lamina tubes,were absent in polyethylene glycol-fused peripheral nerve allografts but commonly observed in negative control and loose-sutured polyethylene glycol peripheral nerve allografts at 21 days postoperatively.Loose-sutured polyethylene glycol peripheral nerve allografts had more pro-inflammatory and less anti-inflammatory macrophages than negative control peripheral nerve allografts.While T cell counts were similarly high in loose-sutured-polyethylene glycol and negative control peripheral nerve allografts,loose-sutured polyethylene glycol peripheral nerve allografts expressed some cytokines/chemokines important for T cell activation at much lower levels at 14 days postoperatively.MHCI expression was elevated in loose-sutured polyethylene glycol peripheral nerve allografts,but MHCII expression was modestly lower compared to negative control at 21 days postoperatively.We conclude that,while polyethylene glycol per se reduces some immune responses of peripheral nerve allografts,successful polyethylene glycol-fusion repair of some axons is necessary to prevent Wallerian degeneration of those axons and immune rejection of peripheral nerve allografts,and produce recovery of sensory/motor functions and voluntary behaviors.Translation of polyethylene glycol-fusion technologies would produce a paradigm shift from the current clinical practice of waiting days to months to repair ablation peripheral nerve injuries.

Validation and performance of three scoring systems for predicting primary non-function and early allograft failure after liver transplantation

Background: Primary non-function(PNF) and early allograft failure(EAF) after liver transplantation(LT) seriously affect patient outcomes. In clinical practice, effective prognostic tools for early identifying recipients at high risk of PNF and EAF were urgently needed. Recently, the Model for Early Allograft Function(MEAF), PNF score by King's College(King-PNF) and Balance-and-Risk-Lactate(BAR-Lac) score were developed to assess the risks of PNF and EAF. This study aimed to externally validate and compare the prognostic performance of these three scores for predicting PNF and EAF. Methods: A retrospective study included 720 patients with primary LT between January 2015 and December 2020. MEAF, King-PNF and BAR-Lac scores were compared using receiver operating characteristic(ROC) and the net reclassification improvement(NRI) and integrated discrimination improvement(IDI) analyses. Results: Of all 720 patients, 28(3.9%) developed PNF and 67(9.3%) developed EAF in 3 months. The overall early allograft dysfunction(EAD) rate was 39.0%. The 3-month patient mortality was 8.6% while 1-year graft-failure-free survival was 89.2%. The median MEAF, King-PNF and BAR-Lac scores were 5.0(3.5–6.3),-2.1(-2.6 to-1.2), and 5.0(2.0–11.0), respectively. For predicting PNF, MEAF and King-PNF scores had excellent area under curves(AUCs) of 0.872 and 0.891, superior to BAR-Lac(AUC = 0.830). The NRI and IDI analyses confirmed that King-PNF score had the best performance in predicting PNF while MEAF served as a better predictor of EAD. The EAF risk curve and 1-year graft-failure-free survival curve showed that King-PNF was superior to MEAF and BAR-Lac scores for stratifying the risk of EAF. Conclusions: MEAF, King-PNF and BAR-Lac were validated as practical and effective risk assessment tools of PNF. King-PNF score outperformed MEAF and BAR-Lac in predicting PNF and EAF within 6 months. BAR-Lac score had a huge advantage in the prediction for PNF without post-transplant variables. Proper use of these scores will help early identify PNF, standardize grading of EAF and reasonably select clinical endpoints in relative studies.

A Single-Cell Landscape of Human Liver Transplantation Reveals a Pathogenic Immune Niche Associated with Early Allograft Dysfunction

Liver transplantation(LT)is the standard therapy for individuals afflicted with end-stage liver disease.Despite notable advancements in LT technology,the incidence of early allograft dysfunction(EAD)remains a critical concern,exacerbating the current organ shortage and detrimentally affecting the prognosis of recipients.Unfortunately,the perplexing hepatic heterogeneity has impeded characterization of the cellular traits and molecular events that contribute to EAD.Herein,we constructed a pioneering single-cell transcriptomic landscape of human transplanted livers derived from non-EAD and EAD patients,with 12 liver samples collected from 7 donors during the cold perfusion and portal reperfusion stages.Comparison of the 75231 cells of non-EAD and EAD patients revealed an EAD-associated immune niche comprising mucosal-associated invariant T cells,granzyme B^(+)(GZMB^(+))granzyme K^(+)(GZMK^(+))natural killer cells,and S100 calcium binding protein A12^(+)(S100A12^(+))neutrophils.Moreover,we verified this immune niche and its association with EAD occurrence in two independent cohorts.Our findings elucidate the cellular characteristics of transplanted livers and the EAD-associated pathogenic immune niche at the single-cell level,thus,offering valuable insights into EAD onset.

Comparison of resistive index and shear-wave elastography in the evaluation of chronic kidney allograft dysfunction

BACKGROUND Detection of early chronic changes in the kidney allograft is important for timely intervention and long-term survival.Conventional and novel ultrasound-based investigations are being increasingly used for this purpose with variable results.AIM To compare the diagnostic performance of resistive index(RI)and shear wave elastography(SWE)in the diagnosis of chronic fibrosing changes of kidney allograft with histopathological results.METHODS This is a cross-sectional and comparative study.A total of 154 kidney transplant recipients were included in this study,which was conducted at the Departments of Transplantation and Radiology,Sindh Institute of Urology and Transplantation,Karachi,Pakistan,from August 2022 to February 2023.All consecutive patients with increased serum creatinine levels and reduced glomerular filtration rate(GFR)after three months of transplantation were enrolled in this study.SWE and RI were performed and the findings of these were evaluated against the kidney allograft biopsy results to determine their diagnostic utility.RESULTS The mean age of all patients was 35.32±11.08 years.Among these,126(81.8%)were males and 28(18.2%)were females.The mean serum creatinine in all patients was 2.86±1.68 mg/dL and the mean estimated GFR was 35.38±17.27 mL/min/1.73 m2.Kidney allograft biopsy results showed chronic changes in 55(37.66%)biopsies.The sensitivity,specificity,positive predictive value(PPV),and negative predictive value(NPV)of SWE for the detection of chronic allograft damage were 93.10%,96.87%%,94.73%,and 95.87%,respectively,and the diagnostic accuracy was 95.45%.For RI,the sensitivity,specificity,PPV,and NPV were 76.92%,83.33%,70.17%,and 87.62%,respectively,and the diagnostic accuracy was 81.16%.CONCLUSION The results from this study show that SWE is more sensitive and specific as compared to RI in the evaluation of chronic allograft damage.It can be of great help during the routine follow-up of kidney transplant recipients for screening and early detection of chronic changes and selecting patients for allograft biopsy.

Risk scores for allograft failure: Are they still useful in liver recipients from donation after circulatory death?

BACKGROUND Liver grafts from donation after circulatory death(DCD)are associated with a higher risk of early graft dysfunction,determined by the warm ischemia and cold ischemia times.It is essential to have precise criteria to identify this complication in order to guide therapeutic strategies.AIM To validate different graft and recipient survival scores in patients undergoing liver transplantation(LT)with DCD grafts.METHODS A retrospective and observational unicentric study was conducted on 65 LT patients with grafts obtained from controlled DCD donors from November 2013 to November 2022.The United Kingdom(UK)risk score,early allograft dysfunction(EAD)Olthoff score,and model for early allograft function(MEAF)score were used to evaluate the risk of graft and recipient survival post-transplant.For survival analysis purposes,we used the Kaplan-Meier method,and the differences between subgroups were compared using the log-rank(Mantel-Cox)test.RESULTS Sixty-five patients were included in the study.The UK risk score did not demonstrate predictive capacity for recipient or graft survival.However,in donors aged over 70 years old(18.4%),it significantly predicted graft survival(P<0.05).According to Kaplan-Meier survival curves,graft survival rates at 6 months,2 years,and 5 years in the futility group dramatically decreased to 50%compared to the other groups(log-rank 8.806,P<0.05).The EAD Olthoff and MEAF scores did not demonstrate predictive capacity for recipient or graft survival.Based on Kaplan-Meier survival curves,patients with a MEAF score≥7 had a lower graft survival rate at 6 months,2 years,and 5 years compared to patients with a lower MEAF score(log-rank 4.667,P<0.05).CONCLUSION In our series,both UK DCD risk score and MEAF score showed predictive capability for graft survival.

Chronic lung allograft dysfunction post-lung transplantation:The era of bronchiolitis obliterans syndrome and restrictive allograft syndrome

Chronic lung allograft dysfunction(CLAD)following lung transplantation limits long-term survival considerably.The main reason for this is a lack of knowledge regarding the pathological condition and the establishment of treatment.The consensus statement from the International Society for Heart and Lung Transplantation on CLAD in 2019 classified CLAD into two main phenotypes:Bronchiolitis obliterans syndrome and restrictive allograft syndrome.Along with this clear classification,further exploration of the mechanisms and the development of appropriate prevention and treatment strategies for each phenotype are desired.In this review,we summarize the new definition of CLAD and update and summarize the existing knowledge on the underlying mechanisms of bronchiolitis obliterans syndrome and restrictive allograft syndrome,which have been elucidated from clinicopathological observations and animal experiments worldwide.

Antimicrobial Effect of Skin for Allograft and Management in Burn Wound

One of the most important functions of skins is to protect our bodies from microbes or pollutant sources. Skins containing physical substances serve as a physical barrier which protects our bodies from pathogens. A healthy skin contains a variety of antibacterial substances such as defensin, cathelicidin and psoriasin. However deep and wide burns cause the skin to lose its original functions, so our skins are exposed to various danger factors. For the burn patients, human alloskin graft serves as a very important temporary biological wound dressing. It protects the wound before autograft procedure, forms revascularization and granulation tissues and protects the wound from an invasion of microbes. This study was conducted with the aim to analyze the antimicrobial effect of cryopreserved allograft (CPA) and glycerol-preserved allograft (GPA) which was a type of allograft widely used for burn patients, and measure the difference in comparison with the fresh skin before processing it. The most common contaminants found in burn patients such as S. aureus, P. aeruginosa, C. albicans and E. coli, were used for experiment. The antimicrobial effect against S. aureus and E. coli was observed in fresh skin and some CPA. In some clinical cases, infection is frequently observed in the wounds treated with allograft, indicating the allograft completely block every kind of microbes. To prevent the infection, it is required to use antibiotics and manage wounds thoroughly.

Radiation sterilization of tissue allografts:A review

Tissue substitutes are required in a number of clinical conditions for treatment of injured and diseased tissues.Tissues like bone,skin,amniotic membrane and soft tissues obtained from human donor can be used for repair or reconstruction of the injured part of the body.Allograft tissues from human donor provide an excellent alternative to autografts.However,major concern with the use of allografts is the risk of infectious disease transmission.Therefore,tissue allografts should be sterilized to make them safe for clinical use.Gamma radiation has several advantages and is the most suitable method for sterilization of biological tissues.This review summarizes the use of gamma irradiation technology as an effective method for sterilization of biological tissues and ensuring safety of tissue allografts.

Evaluation of the updated definition of early allograft dysfunction in donation after brain death and donation after cardiac death liver allografts

BACKGROUND:An updated definition of early allograft dysfunction(EAD) was recently validated in a multicenter study of 300 deceased donor liver transplant recipients.This analysis did not differentiate between donation after brain death(DBD) and donation after cardiac death(DCD) allograft recipients.METHODS:We reviewed our prospectively entered database for all DBD(n=377) and DCD(n=38) liver transplantations between January 1,2006 and October 30,2011.The incidence of EAD as well as its ability to predict graft failure and survival was compared between DBD and DCD groups.RESULTS:EAD was a valid predictor of both graft and patient survival at six months in DBD allograft recipients,but in DCD allograft recipients there was no significant difference in the rate of graft failure in those with EAD(11.5%) compared with those without EAD(16.7%)(P=0.664) or in the rate of death in recipients with EAD(3.8%) compared with those without EAD(8.3%)(P=0.565).The graft failure rate in the first 6 months in those with international normalized ratio ≥1.6 on day 7 who received a DCD allograft was 37.5% compared with 6.7% for those with international normalized ratio <1.6 on day 7(P=0.022).CONCLUSIONS:The recently validated definition of EAD is a valid predictor of patient and graft survival in recipients of DBD allografts.On initial assessment,it does not appear to be a useful predictor of patient and graft survival in recipients of DCD allografts,however a study with a larger sample size of DCD allografts is needed to confirm these findings.The high ALT/AST levels in most recipients of DCD livers as well as the predisposition to biliary complications and early cholestasis make these parameters as poor predictors of graft failure.An alternative definition of EAD that gives greater weight to the INR on day 7 may be more relevant in this population.

Ganglioside promotes the bridging of sciatic nerve defects in cryopreserved peripheral nerve allografts

Previous studies have shown that exogenous gangliosides promote nervous system regeneration and synapse formation. In this study, 10 mm sciatic nerve segments from New Zealand rabbits were thawed from cryopreservation and were used for the repair of left sciatic nerve defects through allograft bridging. Three days later, 1 mL ganglioside solution （1 g/L） was sub- cutaneously iniected into the right hind leg of rabbits. Compared with non-injected rats, muscle wet weight ratio was increased at 2-12 weeks after modeling. The quantity of myelinated fibers in regenerated sciatic nerve, myelin thickness and fiber diameter were elevated at 4-12 weeks after modeling. Sciatic nerve potential amplitude and conduction velocity were raised at 8 and 12 weeks, while conduction latencies were decreased at 12 weeks. Experimental findings indicate that ganglioside can promote the regeneration of sciatic nerve defects after repair with cryopre- served peripheral nerve allografts.

Hepatic flow is an intraoperative predictor of early allograft dysfunction in whole-graft deceased donor liver transplantation: An observational cohort study

BACKGROUND Early allograft dysfunction(EAD)after liver transplantation(LT)is an important cause of morbidity and mortality.To ensure adequate graft function,a critical hepatocellular mass is required in addition to an appropriate blood supply.We hypothesized that intraoperative measurement of portal venous and hepatic arterial flow may serve as a predictor in the diagnosis of EAD.AIM To study whether hepatic flow is an independent predictor of EAD following LT.METHODS This is an observational cohort study in a single institution.Hepatic arterial blood flow and portal venous blood flow were measured intraoperatively by transit flow.EAD was defined using the Olthoff criteria.Univariate and multivariate analyses were used to determine the intraoperative predictors of EAD.Survival analysis and prognostic factor analysis were performed using the Kaplan-Meier and Cox regression models.RESULTS A total of 195 liver transplant procedures were performed between January 2008 and December 2014 in 188 patients.A total of 54(27.7%)patients developed EAD.The median follow-up was 39 mo.Portal venous flow,hepatic arterial flow(HAF)and total hepatic arterial flow were associated with EAD in both the univariate and multivariate analyses.HAF is an independent prognostic factor for 30-d patient mortality.CONCLUSION Intraoperative measurement of blood flow after reperfusion appears to be a predictor of EAD;Moreover,HAF should be considered a predictor of 30-d patient mortality.

Tunica albuginea allograft： a new model of LaPeyronie＇s disease with penile curvature and subtunical ossification

The pathophysiology of LaPeyronie＇s disease （PD） is considered to be multifactorial, involving genetic predisposition, trauma, inflammation and altered wound healing. However, these factors have not yet been validated using animal models. In this study, we have presented a new model obtained by tunica albuginea allograft. A total of 40, 16-week-old male rats were used. Of these, 8 rats served as controls and underwent a 10 × 2-mm-wide tunical excisionwith subsequent autografting, whereas the remaining 32 underwent the same excision with grafting of the defect with another rat＇s tunica. Morphological and functional testing was performed at 1, 3, 7 and 12 weeks after grafting. Intracavernous pressure, the degree of penile curvature and elastic fiber length were evaluated for comparison between the allograft and control groups. The tissues were obtained for histological examination. The penile curvature was significantly greater in the allografted rats as compared with the control rats. The erectile function was maintained in all rats, except in those assessed at 12 weeks. The elastin fiber length was decreased in the allografted tunica as compared to control. SMAD2 expression was detected in the inner part of the allograff, and both collagen-Ⅱ- and osteocalcin-positive cells were also noted. Tunica albuginea （TA） allograft in rats is an excellent model of PD. The persistence of curvature beyond 12 weeks and the presence of ossification in the inner layer of the TA were similar to those observed in men with PD. Validation studies using this animal model would aid understanding of the PD pathophysiology for effective therapeutic interventions.

Acellular nerve allograft promotes selective regeneration

Acellular nerve ailograft preserves the basilar membrane tube and extracellular matrix, which promotes selective regeneration of neural defects via bridging. In the present study, a Sprague Dawley rat sciatic nerve was utilized to prepare acellular nerve allografts through the use of the chemical extraction method. Subsequently, the allograft was transplanted into a 10-mm sciatic nerve defect in Wistar rats, while autologous nerve grafts from Wistar rats served as controls. Compared with autologous nerve grafts, the acellular nerve allografts induced a greater number of degenerated nerve fibers from sural nerves, as well as a reduced misconnect rate in motor fibers, fewer acetylcholine esterase-positive sural nerves, and a greater number of carbonic anhydrase-positive sensory nerve fibers. Results demonstrated that the acellular nerve allograft exhibited significant neural selective regeneration in the process of bridging nerve defects.

Knee salvage procedures: The indications, techniques and outcomes of large osteochondral allografts

The overall incidence of osteochondral defect in the general population is estimated to be 15 to 30 per100000 people.These lesions can become symptomatic causing pain,swelling and decreased function of the knee,and may eventually progress to osteoarthritis.In the young and active population,partial or total knee arthroplasty(TKA)is rarely the treatment of choice due to risk of early failure.Osteochondral allograft transplantation has been demonstrated to be a safe and effective treatment of large osteochondral and chondral defects of the knee in appropriately selected patients.The treatment reduces pain,improves function and is a viable limb salvage procedure for patients,especially young and active patients for whom TKA is not recommended.Either large dowels generated with commercially available equipment or free hand shell allografts can be implanted in more posterior lesions.Current recommendations for fresh allografts stored at4C advise implantation within 21-28 d of procurement for optimum chondrocyte viability,following screening and testing protocols.Higher rates of successful allograft transplantation are observed in younger patients,unipolar lesions,normal or corrected malalignment,and defects that are treated within 12 mo of symptom onset.Patients with bipolar lesions,uncorrectable malalignment,advanced osteoarthritis,and those over40 tend to have less favourable outcomes.

Role of the postoperative cholesterol in early allograft dysfunction and survival after living donor liver transplantation

BACKGROUND:Many studies have confirmed that serum total cholesterol(sTC) concentrations were associated with underlying liver damage and the synthesis capacity of liver.However, the role of postoperative sTC level on evaluating graft function and predicting survival of recipients who underwent liver transplantation has not been discussed.METHODS:Clinical data of 231 living donor liver transplantation recipients from May 2003 to January 2015 were retrospectively collected. Patients were stratified into the low sTC group(sTC <1.42 mmol/L, 57 recipients) and high sTC group(sTC ≥1.42 mmol/L, 174 recipients) according the sTC level on postoperative day 3 based on receiver-operating characteristic curve analysis. The clinical characteristics and postoperative short-and long-term outcomes were compared between the two groups.RESULTS:Recipients with sTC <1.42 mmol/L experienced more severe preoperative disease conditions, a higher incidence of postoperative early allograft dysfunction(38.6% vs 10.3%, P<0.001), 90-day mortality(28.1% vs 10.9%, P=0.002)and severe complications(29.8% vs 17.2%, P=0.041) compared to recipients with sTC ≥1.42 mmol/L. The multivariate analysis demonstrated that sT C <1.42 mmol/L had a 4.08-fold(95% CI:1.83-9.11, P=0.001) and 2.72-fold(95% CI:1.23-6.00,P=0.013) greater risk of developing allograft dysfunction and 90-day mortality, and patients with sTC <1.42 mmol/L had poorer overall recipient and graft survival rates at 1-, 3-, and 5-year than those with sTC ≥1.42 mmol/L(67%, 61% and 61% vs 83%, 71% and 69%, P=0.025; 65%, 59% and 59% vs 81%,68% and 66%, P=0.026, respectively). Cox multivariate anal-ysis showed that sTC <1.42 mmol/L was an independent predicting factor for total recipient survival(HR=2.043; 95% CI:1.173-3.560; P=0.012) and graft survival(HR=1.905; 95% CI:1.115-3.255; P=0.018).CONCLUSIONS:sTC <1.42 mmol/L on postoperative day 3 was an independent risk factor of postoperative early allograft dysfunction, 90-day mortality, recipient and graft survival, which can be used as a marker for predicting postoperative short-and long-term outcomes.

A Single Bundle Anterior Cruciate Ligament Reconstruction (ACL-R) Using Hamstring Tendon Autograft and Tibialis Anterior Tendon Allograft:A Comparative Study

The main purpose of this study patients undergoing a single bundle anterior was to compare the clinical outcomes of cruciate ligament reconstruction (ACL-R) of using quadrupled hamstring (4HT)autografts and two-strand tibialis anterior (2TA) aUografts,and to find out the rate of graft failure and possible causes.We hypothesized that there would be no difference in the clinical outcome,and graft failure would be associated with the use of small sized allograft in young active males with high demand of sports activities.We retrospectively evaluated 222 patients (male,n=167,female,n=55) undergoing ACL-R between January 2010 and July 2014.Of 222 patients,115 were included in the 4HT autograft group and 107 patients in the 2TA allograft group.Inclusion criteria were primary unilateral ACL-R with a minor MCL (<grade Ⅱ)injury with or without meniscus tear and had at least 2.5 years of follow-up.Subjective evaluation was performed using Tegner-Lysholm score,modified Cincinnati knee score,and IKDC knee form.Anteroposterior laxity was assessed using ADT and Lachman test whereas rotational laxity was assessed using pivot shift test.Similarly,functional assessment was performed using range of motion (ROM),Daniel's one-leg hop test,and overall IKDC score.Clinical outcomes were satisfactory and comparable in both groups with no statistically significant difference in all the respective parameters.No statistically significant difference was observed in graft re-rupture rate.However,most graft failures occurred in young active males with high demand of sports activities,graft size smaller than 8 mm,and use of allograft.An autograft with at least 8 mm diameter should be considered in a young active male with high demand of sports activities to avoid graft failure.

Zinc finger protein A20 protects rats against chronic liver allograft dysfunction

AIM： To investigate the effect of zinc finger protein A20 on chronic liver allograft dysfunction in rats. METHODS： AIIogeneic liver transplantation from DA rats to Lewis rats was performed. Chronic liver allograft dysfunction was induced in the rats by administering low-dose tacrolimus at postoperative day （POD） 5. Hepatic overexpression of A20 was achieved by recom- binant adenovirus （rAd.）-mediated gene transfer ad- ministered intravenously every 10 d starting from POD 10. The recipient rats were injected with physiologi- cal saline, rAdEasy-A20 （1 × 109 pfu/30 g weight） or rAdEasy （1 × 109 pfu/30 g weight） every 10 d through the tail vein for 3 mo starting from POD 10. Liver tissue samples were harvested on POD 30 and POD 60. RESULTS： Liver-transplanted rats treated with only tacrolimus showed chronic allograft dysfunction with severe hepatic fibrosis. A20 overexpression ameliorated the effects on liver function, attenuated liver allograft fibrosis and prolonged the survival of the recipient rats. Treatment with A20 suppressed hepatic protein pro- duction of tumor growth factor （TGF）-β1, interleukin- 113, caspase-8, CD40, CD40L, intercellular adhesion molecule-i, vascular cell adhesion molecule-1 and E-selectin. A20 treatment suppressed liver cell apopto- sis and inhibited nuclear factor-KB activation of Kupffer cells （KCs）, liver sinusoidal endothelial cells （LSECs） and hepatic stellate cells （HSCs）, and it subsequently decreased cytokine mRNA expression in KCs and LSECs and reduced the production of TGF-β1 in HSCs. CONCLUSION： A20 might prevent chronic liver allogra- ft dysfunction by re-establishing functional homeostasis of KCs, LSECs and HSCs.

Comparison between direct repair and humana cellular nerve allografting during contralateral C7 transfer to the upper trunk for restoration of shoulder abduction and elbow flexion

Direct coaptation of contralateral C7 to the upper trunk could avoid the interposition of nerve grafts. We have successfully shortened the gap and graft lengths, and even achieved direct coaptation. However, direct repair can only be performed in some selected cases, and partial procedures still require autografts, which are the gold standard for repairing neurologic defects. As symptoms often occur after autografting, human acellular nerve allografts have been used to avoid concomitant symptoms. This study investigated the quality of shoulder abduction and elbow flexion following direct repair and acellular allografting to evaluate issues requiring attention for brachial plexus injury repair. Fifty-one brachial plexus injury patients in the surgical database were eligible for this retrospective study. Patients were divided into two groups according to different surgical methods. Direct repair was performed in 27 patients, while acellular nerve allografts were used to bridge the gap between the contralateral C7 nerve root and upper trunk in 24 patients. The length of the harvested contralateral C7 nerve root was measured intraoperatively. Deltoid and biceps muscle strength, and degrees of shoulder abduction and elbow flexion were examined according to the British Medical Research Council scoring system;meaningful recovery was defined as M3–M5. Lengths of anterior and posterior divisions of the contralateral C7 in the direct repair group were 7.64 ± 0.69 mm and 7.55 ± 0.69 mm, respectively, and in the acellular nerve allografts group were 6.46 ± 0.58 mm and 6.43 ± 0.59 mm, respectively. After a minimum of 4-year follow-up, meaningful recoveries of deltoid and biceps muscles in the direct repair group were 88.89% and 85.19%, respectively, while they were 70.83% and 66.67% in the acellular nerve allografts group. Time to C5/C6 reinnervation was shorter in the direct repair group compared with the acellular nerve allografts group. Direct repair facilitated the restoration of shoulder abduction and elbow flexion. Thus, if direct coaptation is not possible, use of acellular nerve allografts is a suitable option. This study was approved by the Medical Ethical Committee of the First Affiliated Hospital of Sun Yat-sen University, China (Application ID:[2017] 290) on November 14, 2017.

Infusion of donor hepatic non-parenchymal cells prolongs survival of skin allografts in mice:role of microchimerism and IL-4

BACKGROUND: In the mouse skin allograft model, specific immune tolerance to the donor was induced by injection of donor hepatic non-parenchymal cells (NPCs). This markedly prolonged the survival time of the allograft. The mechanism of the induction of immune tolerance with donor hepatic NPCs is thought to be related to microchimerism and the IL-4 level. This work aimed at exploring the way of inducing immune tolerance and understanding the mechanism. METHODS: C57BL/6 (B6) mice were primed by intravenous injection of 2 X10(7) NPCs from C3H mice. Cyclophosphamide (200 mg/kg) was injected intraperitoneally 48 hours later. Eighteen days after the NPC injection, skin from C3H mice was transplanted to B6 mice and the survival of the grafts was assessed. The immune reaction of splenocytes from the treated B6 mice to donor-specific T-cells was measured by H-3-TdR incorporation. Microchimerism in the spleen was determined by flow cytometric analysis sytem (FCAS) analysis, and the serum level of IL-4 was assayed by ELISA at designed times. RESULTS: The survival time of the skin graft was markedly prolonged from 10 days to 70 days in controls. Microchimerism. in the spleen was found as early as day I post-NPC injection, then it increased steadily, and there was a positive relationship between graft survival and the quantity of microchimerism. The ELISA results showed that NPC infusion enhanced IL-4 production, especially in the mice with longer graft survival. CONCLUSION: Donor NPC infusion pre-transplant can prolong the survival of the skin graft and microchimerism and high levels of IL-4 may be involved.

Functional and immunological peculiarities of peripheral nerve allografts

This review addresses the accumulating evidence that live(not decellularized)allogeneic peripheral nerves are functionally and immunologically peculiar in comparison with many other transplanted allogeneic tissues.This is relevant because live peripheral nerve allografts are very effective at promoting recovery after segmental peripheral nerve injury via axonal regeneration and axon fusion.Understanding the immunological peculiarities of peripheral nerve allografts may also be of interest to the field of transplantation in general.Three topics are addressed:The first discusses peripheral nerve injury and the potential utility of peripheral nerve allografts for bridging segmental peripheral nerve defects via axon fusion and axon regeneration.The second reviews evidence that peripheral nerve allografts elicit a more gradual and less severe host immune response allowing for prolonged survival and function of allogeneic peripheral nerve cells and structures.Lastly,potential mechanisms that may account for the immunological differences of peripheral nerve allografts are discussed.