The Evolution of Nonimmune Histological Injury and Its Clinical Relevance in Adult-Sized Kidney Grafts in Pediatric Recipients

To describe the evolution, risk factors and impact of nonimmune histological injury after pediatric kidney transplantation, we analyzed 245 renal allograft protocol biopsies taken regularly from the time of transplantation to 2 years thereafter in 81 consecutive rejection-free pediatric recipients of an adult-sized kidney. Isometric tubular vacuolization was present early after transplantation was not progressive, and was associated with higher tacrolimus pre-dose trough levels. Chronic tubulo-interstitial damage and tubular microcalcifications were already noted at 3 months, were progressive and had a greater association with small recipient size, male donor gender, higher donor age and female recipient gender, but not with tacrolimus exposure. Renal function assessment showed that older recipients had a significant increase in absolute glomerular filtration rate with time after transplantation, which differed from small recipients who showed no increase. It is concluded that progressive, functionally relevant, nonimmune injury is detected early after adult-sized kidney transplantation in pediatric recipients. Renal graft ischemia associated with the donor-recipient size discrepancy appears to be a greater risk factor for this chronic histological injury, suggesting that the exploration of additional therapeutic approaches to increase allograft perfusion could further extend the graft survival benefit of adult-sized kidneys transplanted into small children.     

Low seroprevalence of SARS-CoV-2 antibodies in a liver transplant cohort

Solid organ transplant recipients might be at greater risk for acquisition and mortality because of SARS-CoV-2. There are no data regarding SARS-CoV-2 seroprevalence among liver transplant (LT) recipients, and whether it is different from that of the general population or other immunosuppressed groups. We evaluated the prevalence of IgG SARS-CoV-2 antibodies among LT recipients to estimate the frequency of asymptomatic SARS-CoV-2 infection using serological assays in our outpatient clinic. We conducted a cross-sectional analysis from 10 May to 26 October 2020 of all adult (>18 years) LT recipients that underwent a routine laboratory test for the outpatient clinic follow-up at the Hospital Universitari Vall d’Hebron (Barcelona) in which we included serological testing for SARS-CoV-2. Nine out of 294 LT recipients (3.1%) tested positive for anti-SARS-CoV-2 IgG antibodies. Five of them (55.5%) had suffered clinically symptomatic SARS-CoV-2 infection confirmed by RT-PCR, four (44.4%) had presented compatible symptoms but without microbiological confirmation and only one patient (1/9, 11.1%) tested positive without any previous symptom. SARS-CoV-2 seroprevalence among LT recipients in an area highly affected by the pandemic is lower than in the general population in the same area. These results render the possibility of asymptomatic infection in LT recipients very unlikely.     

To screen or not to screen? The development of a prediction model for aorto-iliac stenosis in kidney transplant candidates

Screening for aorto-iliac stenosis is important in kidney transplant candidates as its presence affects pre-transplantation decisions regarding side of implantation and the need for an additional vascular procedure. Reliable imaging techniques to identify this condition require contrast fluid, which can be harmful in these patients. To guide patient selection for these imaging techniques, we aimed to develop a prediction model for the presence of aorto-iliac stenosis. Patients with contrast-enhanced imaging available in the pre-transplant screening between January 1st, 2000 and December 31st, 2018 were included. A prediction model was developed using multivariable logistic regression analysis and internally validated using bootstrap resampling. Model performance was assessed with the concordance index and calibration slope. Three hundred and seventy-three patients were included, 90 patients (24.1%) had imaging-proven aorto-iliac stenosis. Our final model included age, smoking, peripheral arterial disease, coronary artery disease, a previous transplant, intermittent claudication and the presence of a femoral artery murmur. The model yielded excellent discrimination (optimism-corrected concordance index: 0.83) and calibration (optimism-corrected calibration slope: 0.91). In conclusion, this prediction model can guide the development of standardized protocols to decide which patients should receive vascular screening to identify aorto-iliac stenosis. External validation is needed before this model can be implemented in patient care.     

Management of lung transplantation in the COVID-19 era—An international survey

It is unknown if solid organ transplant recipients are at higher risk for severe COVID-19. The management of a lung transplantation (LTx) program and the therapeutic strategies to adapt the immunosuppressive regimen and antiviral measures is a major issue in the COVID-19 era, but little is known about worldwide practice. We sent out to 180 LTx centers worldwide in June 2020 a survey with 63 questions, both regarding the management of a LTx program in the COVID-19 era and the therapeutic strategies to treat COVID-19 LTx recipients. We received a total of 78 responses from 15 countries. Among participants, 81% declared a reduction of the activity and 47% restricted LTx for urgent cases only. Sixteen centers observed deaths on waiting listed patients and eight centers performed LTx for COVID-19 disease. In 62% of the centers, COVID-19 was diagnosed in LTx recipients, most of them not severe cases. The most common immunosuppressive management included a decreased dose or pausing of the cell cycle inhibitors. Remdesivir, hydroxychloroquine, and azithromycin were the most proposed antiviral strategies. Most of the centers have been affected by the COVID-19 pandemic and proposed an active therapeutic strategy to treat LTx recipients with COVID-19.     

受体血清和Hanks液保存兔角膜植片的内皮细胞比较

目的：评价血清对角膜植片保存的意义。方法：对新鲜兔角膜在受体血清和Hanks液中分别进行24h和72h保存后，各组的平均内皮细胞密度及内皮细胞存活率等指标进行比较。结果：血清74h保存组的植片内皮细胞各项指标均优于Hanks液72h保存组。结论：血清有着维护角膜内皮细胞结构和功能的作用。     

数字化设计与3D打印在自体牙移植术的应用

目的探讨术前数字化设计结合3D打印供体牙模型及受区牙槽窝模型辅助自体牙移植术的效果。方法收集12例因牙折或牙槽骨广泛吸收而无法保留的第一或第二磨牙,将其锥形束CT数据导入Mimics数字化设计软件中,选取匹配度最高的第三磨牙作为供体牙,3D打印出供体牙及受区牙槽窝模型进行术前模拟移植术。术中在供体牙模型引导下进行受区牙槽窝及供体牙的预备,将供体牙移植于受区。术后3、6、12个月复查锥形束CT评估骨重建及牙周膜状况。结果 12例患者均选择根尖孔已完全闭合的第三磨牙作为供体牙即刻移植于磨牙区。7例受区牙槽窝术前存在感染,其中1例因受区患牙感染致牙槽骨广泛吸收。12例手术短期恢复良好,均完成12个月以上随访,其中11例移植牙成功,能正常行使咀嚼功能,1例在术后14个月时出现牙根吸收。结论数字化设计结合3D打印技术能够辅助匹配最合适的供体牙,术前完成受区牙槽窝精准预备,减少供体牙在体外的暴露时间和移植到牙槽窝内的试放次数,有助于自体牙移植成功。     

儿童ABO血型不合与相合肝移植疗效比较的Meta分析

目的  应用Meta分析对儿童ABO血型不合肝移植（ILT）与儿童ABO血型相合肝移植（CLT）的疗效进行比较。方法  检索PubMed、Embase、Cochrane library、中国知网、万方、维普等国内外数据库,检索时间截至2017年5月。根据制定的纳入标准和排除标准筛选符合要求的文献,提取数据。采用Review Manager 5.3软件,应用随机效应模型或固定效应模型进行Meta分析。结果  共纳入11篇英文文献,均为回顾性队列研究。Meta分析结果表明ILT组受者术后1年存活率明显低于CLT组[比值比（OR）=0.64,95%可信区间（CI）0.49~0.83,P=0.0007）];ILT组术后排斥反应发生率明显高于CLT组（OR=1.96,95% CI 1.03~3.72,P=0.04）;两组的术后3、10年受者存活率,术后1、3、10年移植物存活率,术后胆道并发症发生率差异无统计学意义（均为P > 0.05）。结论  与CLT比较,ILT受者1年存活率较低而排斥反应发生率较高,但两组受者和移植物长期存活率及胆道并发症发生率相似。表明ILT是在紧急情况下挽救患者生命或长时间无法等到血型相合的肝源时较为理想的选择。