A Role for Human Renal Tubular Epithelial Cells in Direct Allo-Recognition by CD4+ T-Cells and the Effect of Ischemia-Reperfusion

Direct allorecognition is the earliest and most potent immune response against a kidney allograft. Currently, it is thought that passenger donor professional antigen-presenting cells (APCs) are responsible. Further, many studies support that graft ischemia-reperfusion injury increases the probability of acute rejection. We evaluated the possible role of primary human proximal renal tubular epithelial cells (RPTECs) in direct allorecognition by CD4+ T-cells and the effect of anoxia-reoxygenation. In cell culture, we detected that RPTECs express all the required molecules for CD4+ T-cell activation (HLA-DR, CD80, and ICAM-1). Anoxia-reoxygenation decreased HLA-DR and CD80 but increased ICAM-1. Following this, RPTECs were co-cultured with alloreactive CD4+ T-cells. In T-cells, zeta chain phosphorylation and c-Myc increased, indicating activation of T-cell receptor and co-stimulation signal transduction pathways, respectively. T-cell proliferation assessed with bromodeoxyuridine assay and with the marker Ki-67 increased. Previous culture of RPTECs under anoxia raised all the above parameters in T-cells. FOXP3 remained unaffected in all cases, signifying that proliferating T-cells were not differentiated towards a regulatory phenotype. Our results support that direct allorecognition may be mediated by RPTECs even in the absence of donor-derived professional APCs. Also, ischemia-reperfusion injury of the graft may enhance the above capacity of RPTECs, increasing the possibility of acute rejection.     

5%碳酸氢钠严格控制代谢性酸中毒对活体肾移植患者术后早期肾功能的影响

目的：观察使用5%碳酸氢钠严格控制代谢性酸中毒是否可改善活体肾移植患者术后早期肾功能。方法：选择2019年3月至2020年3月于中国科学技术大学附属第一医院择期行活体肾移植手术的120例尿毒症患者为研究对象，随机分为观察组和对照组。观察组术中根据碱剩余（BE）测量值补充5%碳酸氢钠，维持－3 mmol/L≤BE≤+3 mmol/L。对照组仅在明显代谢性酸中毒（BE≤－10 mmol/L或pH≤7.25）时才补充5%碳酸氢钠。调整分钟通气量，使PaCO2在正常范围内。记录患者麻醉前（T0）、麻醉诱导后10 min（T1）、肾动脉血流开放前（T2）、肾动脉血流开放后5 min（T3）、手术结束时（T4）的血流动力学指标及术中出血量、输液量、手术时间。记录术后1、2、3、7、30 d的肌酐、尿素氮及尿量。结果：与对照组相比，观察组术中5%碳酸氢钠输注量明显增加，去氧肾上腺素使用量明显减少（P<0.05），对照组无输注5%碳酸氢钠指征；观察组术毕时pH、BE明显大于对照组（P<0.05）。与T0时比较，T3时两组MAP、CVP均明显降低（P<0.05）。观察组术后1、2、3、7 d血肌酐、尿素氮含量明显低于对照组（P<0.05）。观察组术后1、2、3 d尿量明显多于对照组（P<0.05）。结论：活体肾移植术中应用5%碳酸氢钠严格控制代谢性酸中毒可改善术后早期肾功能。     

Peptide Programmed Hydrogels as Safe Sanctuary Microenvironments for Cell Transplantation

Cell transplantation is one of the most promising strategies for the minimally invasive treatment of a raft of injuries and diseases. However, a standing challenge to its efficacy is poor cell survival due to a lack of mechanical protection during administration and an unsupportive milieu thereafter. In response, a shear‐injectable nanoscaffold vector is engineered considering the three equal requirements of protection, support, and survival. Here, the programmed peptide assembly of tissue‐specific epitopes presents a safe sanctuary microenvironment for the transplantation of cells. For the first time, a mechanistic understanding of the multifactorial role of the nanoscaffold in promoting cell survival is presented, where initial cell survival is dependent on the fluid mechanic process of droplet formation rather than on shear rate. However, provided is the first report of the most critical component of a transplantation vector, distinguishing feigned biological support from mechanical properties from true ongoing biological support post transplantation. This is achieved via the presentation of amino acid constituents that significantly improve the efficacy of the vector compared to a biocompatible, yet inert analogue. Together, the peptide‐programmed hydrogels enable fundamental rules for the engineering of advanced treatment strategies with wide reaching implications for tissue repair and biofabrication.     

Transplanted Neural Stem Cells Modulate Regulatory T, γδ T Cells and Corresponding Cytokines after Intracerebral Hemorrhage in Rats

The immune system, particularly T lymphocytes and cytokines, has been implicated in the progression of brain injury after intracerebral hemorrhage (ICH). Although studies have shown that transplanted neural stem cells (NSCs) protect the central nervous system (CNS) from inflammatory damage, their effects on subpopulations of T lymphocytes and their corresponding cytokines are largely unexplored. Here, rats were subjected to ICH and NSCs were intracerebrally injected at 3 h after ICH. The profiles of subpopulations of T cells in the brain and peripheral blood were analyzed by flow cytometry. We found that regulatory T (Treg) cells in the brain and peripheral blood were increased, but γδT cells (gamma delta T cells) were decreased, along with increased anti-inflammatory cytokines (IL-4, IL-10 and TGF-β) and decreased pro-inflammatory cytokines (IL-6, and IFN-γ), compared to the vehicle-treated control. Our data suggest that transplanted NSCs protect brain injury after ICH via modulation of Treg and γδT cell infiltration and anti- and pro-inflammatory cytokine release.     

大承气汤联合电针在治疗肝移植术后腹内高压中的应用效果

目的探讨大承气汤联合电针在治疗肝移植术后腹内高压中的应用效果。方法将53例肝移植术后腹内高压（腹内压≥1.330kPa）患者按随机数字表法分为2组：对照组26例采用胃肠减压,静脉营养支持,纠正水、电解质紊乱和酸碱平衡,静脉泵入生长抑素抑制肠液分泌,合理应用抗生素控制感染等常规治疗;治疗组27例在常规治疗基础上采用大承气汤联合电针治疗。治疗1周,比较2组临床效果及腹内压变化情况。结果治疗1周后治疗组有效27例,有效率为100.0%,对照组有效23例,有效率为88.5%,治疗组有效率显著高于对照组（P〈0.05）。治疗组治疗后1-7d腹内压明显低于对照组（P〈0.01）。结论在常规治疗基础上运用大承气汤联合电针治疗肝移植术后腹内高压是一种促进肝移植术后腹胀患者肠蠕动,降低腹内压,减轻腹胀的安全有效方法。     

The Role of CTLA4 and Its Polymorphisms in Solid Organ and Haematopoietic Stem Cell Transplantation

HLA matching, transplantation technique, or underlying disease greatly influences the probability of long-term transplantation success. It has been hypothesised that genetic variation affecting antigen presentation also contributes to the outcomes of both solid organ transplantation and allogeneic haematopoietic stem cell transplantation (AHSCT). Those genes, along with those responsible for innate and adaptive immunity, have become targets of investigation. In this review, we focus on the role of CTLA4 in the process of acute graft rejection and summarise the progress in our understanding of its role in predicting the outcome. We present the results of the latest studies investigating the link between CTLA4 gene variability and AHSCT, as well as organ transplantation outcomes. While some studies found a link between +49 A/G and −318 C/T and transplantation outcomes, comprehensive meta-analyses have failed to present any association. The most recent field reviews suggest that the −1772 T/C (rs733618) CC genotype is weakly associated with a lower risk of acute graft rejection, while +49 A/G might be clinically meaningful when investigated in the context of combinations with other polymorphisms. Studies verifying associations between 12 CTLA4 gene SNPs and AHSCT outcomes present inexplicit results. Some of the most commonly studied polymorphisms in this context include +49 A/G (rs231775) and CT60 A/G (rs3087243). The results signify that, in order to understand the role of CTLA4 and its gene polymorphisms in transplantology, further studies must be conducted.     

Digital PCR Panel for Sensitive Hematopoietic Chimerism Quantification after Allogeneic Stem Cell Transplantation

Accurate and sensitive determination of hematopoietic chimerism is a crucial diagnostic measure after allogeneic stem cell transplantation to monitor engraftment and potentially residual disease. Short tandem repeat (STR) amplification, the current “gold standard” for chimerism assessment facilitates reliable accuracy, but is hampered by its limited sensitivity (≥1%). Digital PCR (dPCR) has been shown to combine exact quantification and high reproducibility over a very wide measurement range with excellent sensitivity (routinely ≤0.1%) and thus represents a promising alternative to STR analysis. We here aimed at developing a whole panel of digital-PCR based assays for routine diagnostic. To this end, we tested suitability of 52 deletion/insertion polymorphisms (DIPs) for duplex analysis in combination with either a reference gene or a Y-chromosome specific PCR. Twenty-nine DIPs with high power of discrimination and good performance were identified, optimized and technically validated. We tested the newly established assays on retrospective patient samples that were in parallel also measured by STR amplification and found excellent correlation. Finally, a screening plate for initial genotyping with DIP-specific duplex dPCR assays was designed for convenient assay selection. In conclusion, we have established a comprehensive dPCR system for precise and high-sensitivity measurement of hematopoietic chimerism, which should be highly useful for clinical routine diagnostics.