Correlation between histone H3K4 trimethylation and DNA methylation and evaluation of the metabolomic features in acute rejection after kidney transplantation.

OBJECTIVE: To investigate the difference between trimethylation of monocyte histone H3K4 and DNA methylation in acute rejection (AR) after renal transplantation in rats and reveal the epigenetic mechanism of the AR rats based on metabolomics. METHOD: Peripheral blood mononuclear cells (PBMCs) were isolated, and CD4 +CD25 + Treg cells were sorted by flow cytometry. The Foxp3 mRNA and protein levels of CD4 +CD25 + Treg cells were detected by real-time RT-PCR and Western blotting, respectively. High-throughput screening was applied to evaluate the H3K4 methylation of monocytes using chromatin immunoprecipitation with DNA microarray (ChIP-chip) and verified by ChIP with real-time PCR (ChIP-qPCR). Methylated DNA immunoprecipitation sequencing was combined with real-time PCR (MeDIP-qPCR) to detect the DNA methylation level of positive genes (ABCC4, Mef2d, Tbx1 and Eif6). Real-time quantitative PCR (qRT-PCR) and Western blotting were used to detect the mRNA and protein levels of positive genes. The difference in lipid metabolism in the blood of (non) acute rejection rats was analysed by HPLC/MS. RESULTS: AR rats showed an apparent increase in BUN and Cr levels, as well as IL-2, IL-10 and IFN-γ. Compared with non-AR rats, the expression of CD4 +CD25 + Treg cells and Foxp3 mRNA and protein were significantly lower in AR rats. AR rats also showed an increase in H3K4 trimethylation of CD4 +CD25 + Treg and decrease in DNA methylation. There were significant differences in the DNA methylation level of four positive genes between AR and non-AR rats (P<0.05), in addition to differences in the expression levels of mRNA and protein. Pathological examination of the transplanted kidney indicated that AR rats had more severe pathological injury of the kidney than the non-AR rats. There were significant increase in the contents of several phosphatidylcholines, lysophosphatidylcholine, free fatty acids and carnitine in AR rats which detected by HPLC/MS. CONCLUSION: H3K4 trimethylation increased in PBMCs in AR rats, while DNA methylation decreased, indicating the presence of epigenetic differences between AR and non-AR rats. Metabolomic studies indicated a significant increase in AR rats in the contents of several metabolites, such as phosphatidylcholines, lysophosphatidylcholine, free fatty acids and carnitine, suggesting an increasein phospholipase activity and leading to an energy metabolism imbalance with intensification of ß-oxidation. DNA methylation may be associated with an increase in phosphatidylcholines, lysophosphatidylcholine and free fatty acids in AR rats, which may further affect energy metabolism by enhancing the tricarboxylic acid cycle in AR rats.

Association between Nod-like receptor protein 3 inflammasome and gouty nephropathy.

Crystalized deposits of monosodium urate activate the Nod-like receptor protein 3 (NLRP3) inflammasome, resulting in kidney damage. The present study investigated whether the NLRP3 inflammasome is associated with the progression of hyperuricaemia and gouty nephropathy. Adult male patients were recruited at the Affiliated Baoan Hospital of Shenzhen and divided into three groups of 15 patients each: The control group, the hyperuricaemia group and the gouty nephropathy group. General characteristics and organ function indicators were also measured for each patient. NLRP3, apoptosis-associated speck like protein (ASC) and caspase-1 mRNA and protein expressions in peripheral blood mononuclear cells were detected. The expression of certain downstream inflammatory factors, including interleukin (IL)-1ß and IL-18 were also assessed in plasma. The results demonstrated that the concentration of uric acid and creatinine were increased in the hyperuricaemia and gouty nephropathy groups compared with the control group. NLRP3, ASC and caspase-1 mRNA and protein expression, and IL-1ß and IL-18 expression were increased in the hyperuricaemia and gouty nephropathy groups compared with the control group. In addition, ASC and caspase-1 mRNA and protein expression, and IL-1ß expression were higher in the gouty nephropathy group compared with the hyperuricaemia group. In conclusion, the present results supported the hypothesis that the NLRP3 inflammasome signalling pathway is associated with gouty nephropathy leading to initiation of the inflammatory response and causing renal damage.

NLRP3 inflammasome and lipid metabolism analysis based on UPLC-Q-TOF-MS in gouty nephropathy.

To determine the differences in plasma metabolism between healthy patients and patients with hyperuricaemia and gouty nephropathy, the present study identified differentially expressed metabolites associated with gouty nephropathy. Furthermore, the NLRP3 inflammasome signalling pathway in gouty nephropathy was explored, and the mechanism of hyperuricaemia­induced renal damage. Adult male patients examined between July 2016 and June 2017 were selected as the patient cohort for the present study from the Affiliated Bao'an Hospital of Shenzhen, Southern Medical University (Shenzhen, China). These patients were divided into three groups of 30 patients each: Control, hyperuricaemia and gouty nephropathy groups. The expression levels of NLRP3, ASC and caspase­1 mRNA and protein were detected in peripheral blood mononuclear cells, and the plasma levels of IL­1ß and IL­18. Ultra­performance liquid chromatography coupled with quadrupole time­of­flight mass spectrometry was used to determine differential levels of metabolites between patients from different groups, in order to identify potential biomarkers. The expression of the NLRP3 inflammasome in peripheral blood mononuclear cells, and the levels of IL­1ß and IL­18 in the plasma were increased in the gouty nephropathy group compared with the control and hyperuricaemia groups. In addition, 46 metabolites were identified as potential plasma metabolic biomarkers that were able to distinguish gouty nephropathy from hyperuricaemia. The majority of these metabolites were involved in lipid metabolism, in particular the activity of phospholipase Α2 and ß­oxidation. These data indicated that lipid metabolism and the NLRP3 inflammasome serve a pivotal role in gouty nephropathy. In addition, the results suggested that lipids may mediate the progression of gouty nephropathy through the activity of phospholipase A2, ß­oxidation and activation of the NLRP3 inflammasome.

Successful one-stage extraction of an intracardiac and intravenous leiomyoma through the right atrium under transesophageal ultrasound monitoring.

PURPOSE: Intravenous leiomyomatosis is a rare disorder characterized by benign smooth-muscle tumours, termed leiomyomas, which originate from uterine leiomyomas or pelvic veins. Tumours may extend into the right-sided heart chambers, termed intracardiac leiomyomatosis (ICLM), and may be potentially life-threatening due to mechanical interference with cardiac structures or pulmonary arteries. While surgical excision is the optimal therapy, incomplete retrieval of a tumour or fatal retroperitoneal hemorrhage may occur. We present a case where intraoperative transesophageal ultrasound (TEU) guided complete removal of an intracardiac leiomyoma in a single-stage surgery solely through the right atrium without vein injury. CLINICAL FEATURES: A 46-yr-old female patient presented with a two-week history of exertional dyspnea, palpitations, and syncope. Preoperative imaging modalities revealed a continuous solid mass extending from the inferior vena cava (IVC) into the right atrium, and the patient subsequently underwent open heart surgery for tumour removal and definitive diagnosis. A systematic intraoperative TEU examination performed before resection showed that the serpentine tumour was free from any attachment to the IVC and the heart. Furthermore, the diameter of the intracardiac end of the tumour was wider than that of the IVC. Given these findings, the surgeons carefully drew the cord-like tumour out of the right atrium under close TEU monitoring without vein injury. Post-extraction TEU examination showed complete removal of the tumour. Microscopic examination of the specimen confirmed the diagnosis of intravenous leiomyomatosis. CONCLUSIONS: For cases with ICLM, intraoperative TEU plays a significant role in helping to plan the surgical approach, monitor the movement of the tumour and the IVC during the extraction, and assess the completeness of tumour resection.