Analysis of risk factors for impaired wound healing after kidney transplantation.

To analyse risk factors for impaired wound healing after kidney transplantation to guide clinical decision-making. A retrospective analysis was performed on patients who received kidney transplantation from January 1, 2019, to May 1, 2021, at Kidney Transplantation Center in Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine. A case-control study was used to identify a cohort of patients with similar baseline characteristics according to 1:4 ratio. Patients were divided into two groups according to whether there was impaired wound healing after surgery. The basic data and clinical examinations between the two groups were compared, and the risk factors for impaired wound healing after kidney transplantation were analysed using univariate and multivariate analyses. According to the data type, independent samples t-test or Chi-squared test was used for comparison between groups. Furthermore, multivariate logistic regression analysis was used to analyse different risk factors and calculate the odds ratio (OR) and 95% confidence interval (CI) of each factor. A total of 18 patients showed impaired wound healing after kidney transplantation. And we conducted 72 statically matched controls. Age, diabetes, transplant types, body mass index (BMI), albumin, haemoglobin, and wound infection were statistically different between the two groups. The factors with statistically significant differences in univariate analysis were included in multivariate logistic regression analysis. The results showed that BMI > 25, fasting blood glucose level, albumin level, and prealbumin level were independent risk factors for impaired wound healing after kidney transplantation. Risk factors for impaired wound healing after kidney transplantation can be detected after surgery. Strengthening postoperative monitoring and early intervention of recipients with such factors may effectively prevent impaired wound healing after kidney transplantation.

The N6-methyladenosine mRNA methylase METTL14 promotes renal ischemic reperfusion injury via suppressing YAP1.

Renal ischemia-reperfusion injury (IRI) is one of the most common causes of acute kidney injury (AKI), which is closely related to high morbidity and mortality. However, the pathogenesis underlying renal IRI is complex and not fully defined. N6-methyladenosine (m6A) was recently found to be an abundant modification in mammalian messenger RNAs. It is implicated in various biological processes, while the role of m6A in IRI is not illustrated. Here we show that the m6A-methylated RNA level and its methyltransferase METTL14 are elevated in human AKI renal tissues and IRI HK-2 cells. Moreover, METTL14 knockdown protects the kidney against IRI in vitro and in vivo. Mechanistically, we identified that YAP1 is a direct target of METTL14 in AKI progression. Inhibition of YAP1-TEAD signaling by peptide 17 abrogates the protective effect of METTL14 against IRI in vitro and in vivo. Taken together, these results reveal that the N6-methyladenosine mRNA methylase METTL14 promotes the renal IRI via suppressing YAP1. The discovery of the METTL14-YAP1 pathway provides an important new perspective for understanding AKI and is conducive to revealing new therapeutic strategies and targets.

Gene signature and prediction model of the mitophagy-associated immune microenvironment in renal ischemia-reperfusion injury.

Background: Renal ischemia-reperfusion injury (IRI) is an inevitable occurrence during kidney transplantation. Mitophagy, ferroptosis, and the associated immune microenvironment (IME) have been shown to play important roles in renal IRI. However, the role of mitophagy-associated IME genes in IRI remains unclear. In this study, we aimed to construct a prediction model of IRI prognosis based on mitophagy-associated IME genes. Method: The specific biological characteristics of the mitophagy-associated IME gene signature were comprehensively analyzed using public databases such as GEO, Pathway Unification, and FerrDb. Correlations between the expression of prognostic genes and immune-related genes and IRI prognosis were determined by Cox regression, LASSO analysis, and Pearson's correlation. Molecular validation was performed using human kidney 2 (HK2) cells and culture supernatant as well as the serum and kidney tissues of mice after renal IRI. Gene expression was measured by PCR, and inflammatory cell infiltration was examined by ELISA and mass cytometry. Renal tissue damage was characterized using renal tissue homogenate and tissue sections. Results: The expression of the mitophagy-associated IME gene signature was significantly correlated with IRI prognosis. Excessive mitophagy and extensive immune infiltration were the primary factors affecting IRI. In particular, FUNDC1, SQSTM1, UBB, UBC, KLF2, CDKN1A, and GDF15 were the key influencing factors. In addition, B cells, neutrophils, T cells, and M1 macrophages were the key immune cells present in the IME after IRI. A prediction model for IRI prognosis was constructed based on the key factors associated with the mitophagy IME. Validation experiments in cells and mice indicated that the prediction model was reliable and applicable. Conclusion: We clarified the relationship between the mitophagy-related IME and IRI. The IRI prognostic prediction model based on the mitophagy-associated IME gene signature provides novel insights on the prognosis and treatment of renal IRI.

A simple nomogram for predicting infectious diseases in adult kidney transplantation recipients.

Objective: To investigate the risk factors of infectious diseases in adult kidney transplantation recipients and to establish a simple and novel nomogram to guide the prophylactic antimicrobial therapy. Methods: Patients who received kidney transplantation between January 2018 and October 2021 were included in the study and were divided into a training and a testing set at a 1:1 ratio. Risk factors correlated to infectious diseases were selected using a Least Absolute Shrinkage and Selection Operator (LASSO) regression model. The prediction model was built by incorporating the variables selected by the LASSO model into a logistic regression equation. Calibration curves and receiver operating characteristic (ROC) curves were also applied to assess the model calibration and discrimination. A nomogram consisting of the selected factors was established to provide individualized risks of developing infections. Decision curve analysis (DCA) was adopted to estimate the net benefit and reduction in interventions for a range of clinically reasonable risk thresholds. Results: In all, 863 adult kidney recipients were included in the study, and 407 (47.16%) of them developed infectious diseases during the 3-year follow-up period. A total of 8 variables were selected using LASSO regression and were retained for subsequent model construction and infection prediction. The area under the curve (AUC) was 0.83 and 0.81 in the training and testing sets, with high F scores of 0.76 and 0.77, sensitivity of 0.76 and 0.81, and specificity of 0.88 and 0.74, respectively. A novel nomogram was developed based on 8 selected predictors (requirement for albumin infusion, requirement for red blood cell infusion, triglyceride, uric acid, creatinine, globulin, neutrophil percentage, and white blood cells). The net benefit indicated that the nomogram would reduce unnecessary interventions at a wide range of threshold probabilities in both sets. Conclusions: Adult kidney transplantation recipients are high-risk hosts for infectious diseases. The novel nomogram consisting of 8 factors reveals good predictive performance and may promote the reasonable antimicrobial prescription. More external validations are required to confirm its effectiveness for further clinical application.

Prophylactic effect of low-dose trimethoprim-sulfamethoxazole for Pneumocystis jirovecii pneumonia in adult recipients of kidney transplantation: a real-world data study.

OBJECTIVES: To evaluate the efficacy and safety of low-dose trimethoprim (TMP)-sulfamethoxazole (SMX) (TMP-SMX) as the primary prophylaxis for Pneumocystis jirovecii pneumonia (PJP) in adult recipients of kidney transplantation. METHODS: Three kinds of prescriptions in kidney recipients were documented, including 20 mg TMP/100 mg SMX oral daily, 20 mg TMP/100 mg SMX oral every other day, and nonprophylaxis. The primary outcome was the incidence of PJP in the first 180 days of follow-up after kidney transplantation. The secondary outcomes were changes in renal and liver function. RESULTS: Among the 1469 recipients, 1066 (72.56%) received 20 mg TMP/100 mg SMX daily, 127 (8.65%) received 20 mg TMP/100 mg SMX every other day, and 276 (18.79%) did not have prophylaxis prescription. The 276 recipients in the nonprophylaxis group had 124.92 person-years of follow-up, during which PJP occurred in 29 patients, for an incidence rate of 23.21 (95% confidence interval 15.76-32.72) per 100 person-years. The TMP-SMX daily group and the TMP-SMX every other day group had 524.89 and 62.07 person-years of follow-up, respectively, with no occurrence of PJP. There was no significant difference among the three groups in changes in renal and liver function (P >0.05, respectively). A total of 111 recipients in each group were enrolled in the propensity score matching analysis. It was revealed that the 111 nonprophylaxis recipients had 51.27 person-years of follow-up and 10 PJP cases. Prophylaxis was considered effective because there was a significant difference between the three groups (P <0.001). CONCLUSION: Low-dose TMP-SMX prophylaxis significantly reduces the incidence of PJP within 6 months after kidney transplantation and has a favorable safety profile.

[Effects of moxibustion at 45 ℃ on blood lipoids and serum level of ox-LDL and NO in rats with hyperlipidemia].

OBJECTIVE: To observe the effects of moxibustion at different temperatures (38 ℃ and 45 ℃) on blood lipoids and serum level of oxidized low density lipoprotein (ox-LDL) and nitric oxide (NO) in rats with hyperlipidemia, and to explore the correlation between regulating blood fat and anti-oxidative stress and protection of vascular endothelium of moxibustion at 45 ℃. METHODS: According to random number table, 60 SD rats were randomly divided into a normal group, a model group, a moxibustion at 38 ℃ group and a moxibustion at 45 ℃ group, 15 rats in each group. The rats in the normal group received no treatment; the rats in the remaining three groups were fed with high-fat diet for 8 weeks to prepare rat models of hyperlipidemia. After successful modeling, the rats in the model group received no treatment; the rats in the moxibustion at 38 ℃ group and moxibustion at 45 ℃ group were treated with moxibustion at "Shenque" (CV 8) and "Zusanli" (ST 36), and the temperature was controlled at (38±1) ℃ and (45±1) ℃, respectively. The moxibustion was given for 10 min at each acupoint, once every two days, and totally 4-week treatment was given. After treatment, the levels of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) were measured by using biochemical colorimetric method; the levels of ox-LDL and NO were measured by using ELISA method. RESULTS: ① Compared with the normal group, the levels of TC, TG and LDL-C were significantly increased in the model group (all P<0.01); compared with the model group and moxibustion at 38 ℃ group, the levels of TC, TG and LDL-C were significantly decreased in the moxibustion at 45 ℃ group (P<0.01，P<0.05); compared with the model group, the levels of TC, TG and LDL-C were insignificantly decreased in the moxibustion at 38 ℃ group (all P>0.05). ② Compared with the normal group, the level of ox-LDL was increased but that of NO was decreased in the model group (both P<0.01); compared with the model group and moxibustion at 38 ℃ group, the level of ox-LDL was decreased but that of NO was increased in the moxibustion at 45 ℃ group (P<0.01, P<0.05); compared with the model group, the level of ox-LDL was decreased but that of NO was increased in the moxibustion at 38 ℃ group (both P<0.05). CONCLUSION: Moxibustion at 45 ℃ has regulating effects on blood lipid in rats with hyperlipidemia, which can regulate blood lipid through various ways, such as anti-oxidative stress and protection of vascular endothelium.