Identification and validation of disulfidptosis-related gene signatures and their subtype in diabetic nephropathy.

Background: Diabetic nephropathy (DN) is the most common complication of diabetes, and its pathogenesis is complex involving a variety of programmed cell death, inflammatory responses, and autophagy mechanisms. Disulfidptosis is a newly discovered mechanism of cell death. There are little studies about the role of disulfidptosis on DN. Methods: First, we obtained the data required for this study from the GeneCards database, the Nephroseq v5 database, and the GEO database. Through differential analysis, we obtained differential disulfidptosis-related genes. At the same time, through WGCNA analysis, we obtained key module genes in DN patients. The obtained intersecting genes were further screened by Lasso as well as SVM-RFE. By intersecting the results of the two, we ended up with a key gene for diabetic nephropathy. The diagnostic performance and expression of key genes were verified by the GSE30528, GSE30529, GSE96804, and Nephroseq v5 datasets. Using clinical information from the Nephroseq v5 database, we investigated the correlation between the expression of key genes and estimated glomerular filtration rate (eGFR) and serum creatinine content. Next, we constructed a nomogram and analyzed the immune microenvironment of patients with DN. The identification of subtypes facilitates individualized treatment of patients with DN. Results: We obtained 91 differential disulfidptosis-related genes. Through WGCNA analysis, we obtained 39 key module genes in DN patients. Taking the intersection of the two, we preliminarily screened 20 genes characteristic of DN. Through correlation analysis, we found that these 20 genes are positively correlated with each other. Further screening by Lasso and SVM-RFE algorithms and intersecting the results of the two, we identified CXCL6, CD48, C1QB, and COL6A3 as key genes in DN. Clinical correlation analysis found that the expression levels of key genes were closely related to eGFR. Immune cell infiltration is higher in samples from patients with DN than in normal samples. Conclusion: We identified and validated 4 DN key genes from disulfidptosis-related genes that CXCL6, CD48, C1QB, and COL6A3 may be key genes that promote the onset of DN and are closely related to the eGFR and immune cell infiltrated in the kidney tissue.

Elevated plasma FXII is associated with disease activity in ANCA-associated vasculitis: A Retrospective Cross-Sectional Study in Western China.

This study examined whether plasma FXII levels reflect disease activity in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Plasma FXII levels were detected by ELISA in 127 patients with AAV, and their associations with disease activity and plasma myeloperoxidase (MPO)-ANCA titre were examined. Immunofluorescent co-staining of FXII and neutrophils was performed on the renal tissues of patients with AAV. MPO expression in renal biopsy tissues was determined by immunohistochemical staining. The association between plasma FXII levels and histological activity was assessed in 82 patients who underwent kidney biopsy. Plasma FXII levels were considerably increased in patients with clinically active AAV compared to those in clinical remission and healthy individuals. Plasma FXII levels correlated positively with creatinine (r = 0.377), CRP (r = 0.222), urine red blood cell (r = 0.203), serum MPO-ANCA titer (r = 0.353), white blood cell (r = 0.194), percentage of glomeruli with crescents (P = 0.001), capillary breaks (P = 0.001), interstitial inflammation (P < 0.001) and fibrinoid necrosis (p < 0.001) on kidney biopsy. The plasma FXII optimal cut-off value for evaluating AAV activity was 24.5 µg/mL (sensitivity = 0.81, specificity = 0.82, P = 0.0001), which was superior to that achieved using conventional serologic biomarkers. Co-expression of FXII and neutrophils was higher, with increased MPO expression, in renal tissue with pathologically active AAV than that observed in pathologically inactive tissues. In conclusion, elevated plasma FXII levels reflect AAV clinical and histologic activity, and can serve as markers of active AAV.

Exploring agreement and feasibility between virtual home visits and in-person home visits for peritoneal dialysis patients-a paired study.

INTRODUCTION: Virtual home visits may improve chronic disease management. However, whether they are suitable for peritoneal dialysis (PD) patients has not yet been fully investigated. This study aimed to compare the agreement and acceptance of virtual home visits and in-person home visits in PD patients. METHODS: This was a paired, single center, noninferiority trial. Participants received a virtual home visit and an in-person home visit simultaneously. A home visit checklist was built for standardization visits. The content was divided into three parts: domestic habits (57 items), bag exchange procedures (56 items), and exit site care (53 items). Satisfaction questionnaires for both patients and nurses were designed to assess attitudes toward home visits and socioeconomic effects. RESULTS: A total of 30 PD patients were enrolled in a single center. The information collected from virtual home visits and in-person home visits was found to be highly consistent. The perfect agreement was found in 52/57, 49/56, and 44/53 items (Cohen's kappa 0.81-1.00), substantial agreement in 4/57, 7/56, and 8/53 items (Cohen's kappa 0.61-0.80). Patients reported almost identical satisfaction for virtual home visits and in-person home visits (Z = 0.39, p = 0.70). PD nurses reported similar feasibility and patient cooperation for the two visit types (Z = 0.99, p = 0.33; Z = 1.65, p = 0.10, respectively). In addition, virtual home visits were found to be more cost-effective than in-person home visits. CONCLUSIONS: Virtual home visits information collection was similar to in-person home visits in PD. There were no differences in participant satisfaction and feasibility between the two visit types.

Thrombomodulin activation driven by LXR agonist attenuates renal injury in diabetic nephropathy.

Objective: Inflammation and thrombosis are recognized as interrelated biological processes. Both thrombomodulin (TM) and factor XIII-A (FXIII-A) are involved in inflammation and coagulation process. However, their role in the pathogenesis of diabetic nephropathy (DN) remains unclear. In vitro study, the liver X receptor (LXR) agonist T0901317 can up-regulate the expression of TM in glomerular endothelial cells. Now we evaluated the interaction between TM activation and FXIII-A and their effects against renal injury. Methods: We first evaluated the serum levels of FXIII-A and TM and the expression of TM, LXR-α and FXIII-A in renal tissues of patients with biopsy-proven DN. We then analyzed the expression of TM, LXR-α and FXIII-A in renal tissues of db/db DN mice after upregulating TM expression via T0901317 or downregulating its expression via transfection of TM shRNA-loaded adenovirus. We also investigated the serum levels of Tumor necrosis factor (TNF)-α, Interleukin (IL)-6, creatinine, and urinary microalbumin level in db/db mice. Results: Our study showed that elevations in serum levels of FXIII-A positively correlated to the serum levels of TM and were also associated with end-stage kidney disease in patients with DN. The number of TM+ cells in the renal tissues of patients with DN negatively correlated with the number of FXIII-A+ cells and positively correlated with the number of LXR-α+ cells and estimated glomerular filtration rate (eGFR), whereas the number of FXIII-A+ cells negatively correlated with the eGFR. Conclusion: Thrombomodulin activation with T0901317 downregulated FXIII-A expression in the kidney tissue and alleviated renal injury in db/db mice.

Management of peritoneal dialysis under COVID-19: The experience in Sichuan Province People's Hospital, China.

The outbreak of coronavirus disease 2019 (COVID-19) is becoming a severe challenge to China and the whole world. By now, there is no report about medical support to peritoneal dialysis (PD) patient during COVID-19 pandemic. In this essay, we summed up our safety measures on how to protect PD patients and our staffs, and our experience on how to ensure the dialysis treatment of PD patients during the pandemic period. Using of telehealth has potential to improve patient care quality. As a result, by applying all the actions and efforts above, most of patients got enough medical support. According to the patient survey, 11 patients (3.3% of the total) reduced their treatment of dialysis exchange due to the shortage of PD solution or the affection of the pandemic. None of the PD patient and staff reported COVID-19. We successfully prevented COVID-19 transmission and ensured medical safety in our PD patients during the crisis.

Effects of Niaoduqing Particles () on Delaying Progression of Renal Dysfunction: A Post-trial, Open-Label, Follow-up Study.

OBJECTIVE: To follow up the participants of the randomized clinical trial "Efficacy and Safety of Niaoduqing Particles () for Delaying Moderate-to-Severe Renal Dysfunction", and assess the long-term effects of Niaoduqing Particles on delaying the progression of renal dysfunction. METHODS: Participants, who had previously been randomly assigned to receive Niaoduqing Particles or placebo for 24 weeks (146 cases in each group), were invited to follow-up and all were administered Niaoduqing Particles 5 g thrice daily and 10 g before bedtime for 24 weeks. The primary endpoints were changes in baseline serum creatinine (Scr) and estimated glomerular filtration rate (eGFR) after completion of the open-label treatment period. RESULTS: After the double-blind period, the median (interquartile range) changes in Scr were 1.1 (-13.0-24.1) and 11.7 (-2.6-42.9) µmol/L for the Niaoduqing Particle and placebo groups, respectively (P=0.008), and the median changes in eGFRs were-0.2 (-4.3-2.7) and-2.21 (-5.7-0.8) mL•min-1•1.73 m-2, respectively (P=0.016). There were significant differences in the double-blind period changes in renal function between groups. After the open-label period, the median changes in Scr were 9.0 (-10.0-41.9) and 17.5 (-6.0-50.0) µmol/L for the Niaoduqing Particle and placebo groups according to baseline grouping, respectively (P=0.214), and the median changes in eGFRs were-2.3 (-6.4-1.9) and-3.7 (-7.5-1.1) mL•min-1•1.73 m-2, respectively (P=0.134). There were no statistical differences in the open-label period changes in renal function between groups. The eGFR reduction of participants who accepted Niaoduqing Particle treatment for 48 weeks was projected to 2.5 mL•min-1•1.73 m-2 per year. CONCLUSION: Niaoduqing Particles appear to have long-term efficacy for patients with moderate-to-severe renal dysfunction. Although there was no statistical difference, the early use of Niaoduqing Paticles seems to ameliorate the worsening of renal function. (Trial registration No. ChiCTR-TRC-12002448).

Efficacy and Safety of Niaoduqing Particles for Delaying Moderate-to-severe Renal Dysfunction: A Randomized, Double-blind, Placebo-controlled, Multicenter Clinical Study.

BACKGROUND: Chronic kidney disease (CKD) with moderate-to-severe renal dysfunction usually exhibits an irreversible course, and available treatments for delaying the progression to end-stage renal disease are limited. This study aimed to assess the efficacy and safety of the traditional Chinese medicine, Niaoduqing particles, for delaying renal dysfunction in patients with stage 3b-4 CKD. METHODS: The present study was a prospective, randomized, double-blind, placebo-controlled, multicenter clinical trial. From May 2013 to December 2013, 300 CKD patients with an estimated glomerular filtration rate (eGFR) between 20 and 45 ml·min-1·1.73 m-2, aged 18-70 years were recruited from 22 hospitals in 11 Chinese provinces. Patients were randomized in a 1:1 ratio to either a test group, which was administered Niaoduqing particles 5 g thrice daily and 10 g before bedtime for 24 weeks, or a control group, which was administered a placebo using the same methods. The primary endpoints were changes in baseline serum creatinine (Scr) and eGFR after completion of treatment. The primary endpoints were analyzed using Student's t-test or Wilcoxon's rank-sum test. The present study reported results based on an intention-to-treat (ITT) analysis. RESULTS: A total of 292 participants underwent the ITT analysis. At 24 weeks, the median (interquartile range) change in Scr was 1.1 (-13.0-24.1) and 11.7 (-2.6-42.9) µmol/L for the test and control groups, respectively (Z = 2.642, P = 0.008), and the median change in eGFR was -0.2 (-4.3-2.7) and -2.2 (-5.7-0.8) ml·min-1·1.73 m-2, respectively (Z = -2.408, P = 0.016). There were no significant differences in adverse events between the groups. CONCLUSIONS: Niaoduqing particles safely and effectively delayed CKD progression in patients with stage 3b-4 CKD. This traditional Chinese medicine may be a promising alternative medication for patients with moderate-to-severe renal dysfunction. TRIAL REGISTRATION: Chinese Clinical Trial Register, ChiCTR-TRC-12002448; http://www.chictr.org.cn/showproj.aspx?proj=7102.

Hydrogen peroxide prevents vascular calcification induced ROS production by regulating Nrf-2 pathway.

BACKGROUND: Although vascular calcification in end-stage renal disease (ESRD) represents a ubiquitous human health problem, effective therapies with limited side effects are still lacking, and the precise mechanisms are not fully understood. The Nrf-2/ARE pathway is a pivotal to regulate anti-oxidative responses in vascular calcification upon ESRD. Although Nrf-2 plays a crucial role in atherosclerosis, pulmonary fibrosis, and brain ischemia, the effect of Nrf-2 and oxidative stress on vascular calcification in ESRD patients is still unclear. The aim of this research was to study the protective role of hydrogen peroxide in vascular calcification and the mechanism of Nrf-2 and oxidative stress on vascular calcification. MATERIALS AND METHODS: Here we used the rat vascular smooth muscle cell model of ß-glycerophosphate-induced calcification resembling vascular calcification in ESRD to investigate the therapeutic effect of 0.01 mM hydrogen peroxide on vascular calcification and further explores the possible underlying mechanisms. RESULTS: Our current report shows the in vitro role of 0.01 mM hydrogen peroxide in protecting against intracellular ROS accumulation upon vascular calcification. Both hydrogen peroxide and sulforaphane pretreatment reduced ROS production, increased the expression of Nrf-2, and decreased the expression of Runx2 following calcification. CONCLUSION: Our study demonstrates that 0.01 mM hydrogen peroxide can effectively protect rat aortic vascular smooth muscle cells against oxidative stress by preventing vascular calcification induced ROS production through Nrf-2 pathway. These data might define an antioxidant role of hydrogen peroxide in vascular calcification upon ESRD.

LXR agonist T0901317 upregulates thrombomodulin expression in glomerular endothelial cells by inhibition of nuclear factor­κB.

Dysfunction of glomerular endothelial cells (GECs) induces a variety of symptoms, including proteinuria, inflammation, vascular diseases, fibrosis and thrombosis. Thrombomodulin (TM) acts as a vasoprotective molecule on the surface of the vascular endothelial cells to maintain the homeostasis of the endothelial microenvironment by suppressing cellular proliferation, adhesion and inflammatory responses. Liver X receptor (LXR), a nuclear receptor (NR) and a bile acid­activated transcription factor, regulates metabolism and cholesterol transport, vascular tension and inflammation. Previous studies indicated that TM expression is upregulated by various NRs; however, it is unclear whether pharmacological modulation of LXR may affect TM expression and GEC function. The current study revealed that LXR activation by its agonist, T0901317, upregulates the expression and activity of TM. This effect was mediated specifically through LXR­α, and not through LXR­ß. Additionally, T0901317 treatment inhibited nuclear factor­κB (NF­κB) signaling and the secretion of high glucose­induced proinflammatory mediators, including tumor necrosis factor­α and interleukin­1ß in GECs. Co­immunoprecipitation experiments determined that treatment with T0901317 enhances the interaction between LXR­α and the transcriptional coactivator, p300, in GEC extracts. The present findings suggest that NF­κB may be a negative regulator of TM expression, and its removal may contribute to TM gene expression, particularly when in competition with the T0901317­enhanced formation of the LXR/p300 complex. Therefore, LXR may be a novel molecular target for manipulating TM in GECs, which may advance the treatment of endothelial cell­associated diseases.

[Effects of Ad-FLT-1/PC on the expression of inflammatory factors in rats with diabetic nephropathy atherosclerosis].

OBJECTIVE: To explore the effect of recombinant adenovirus Ad-FLT-1/PC on the expression of vascular inflammatory factors in rats with diabetic nephropathy atherosclerosis. METHODS: A total of 68 rats of diabetic nephropathy atherosclerosis were randomly divided into three groups of Ad-FLT-1/PC [recombinant adenovirus with protein C (PC) gene, n = 23], Ad-green fluorescence protein (recombinant blank adenovirus with GFP, n = 23), normal saline (n = 22) and compared with normal control (n = 23). And 300 µl of each was transfected via caudal vein. At day 1, 3, 7 and 14 post-transfection, 5 or 6 rats of each group were randomly sacrificed to observe the distribution of vascular fluorescence by frozen section. And the expression of PC was examined by immunohistochemistry (IHC). The expressions of tumor necrosis factor-alpha (TNF-α) and intercellular adhesion molecule 1 (ICAM-1) protein in vascular wall were measured by IHC. RESULTS: At day 3 after an injection of Ad-FLT-1/PC, green fluorescence was observed in vascular endothelium and continued until 14 days. IHC showed protein C in endothelial cells of Ad-FLT-1/PC group was higher than those of Ad-GFP and NS groups at Days 3-14 (P < 0.05). IHC showed the amounts of TNF-α and ICAM-1 in Ad-FLT-1/PC group were lower than those in GFP and NS groups at Day 7 post-transfection (P < 0.05). GFP and NS groups had no difference at all timepoints (P > 0.05). CONCLUSIONS: The recombinant adenovirus Ad-FLT-1/PC may be transfected into vascular walls of rats with diabetic nephropathy atherosclerosis. And exogenous PC can effectively express and protect vascular walls by inhibiting the expression of inflammatory cytokines.

Blockade of B-cell-activating factor suppresses lupus-like syndrome in autoimmune BXSB mice.

B-cell-activating factor (BAFF), a member of the tumour necrosis factor superfamily, plays a critical role in the maturation, homeostasis and function of B cells. In this study, we demonstrated the biological outcome of BAFF blockade in BXSB murine lupus model, using a soluble fusion protein consisting of human BAFF-R and human mutant IgG4 Fc. Mutation of Leu(235) to Glu in IgG4 Fc eliminated antibody-dependent cell cytotoxicity (ADCC) and complement lysis activity, and generated a protein devoid of immune effector functions. Treatment of BXSB mice with BAFF-R-IgG4mut fusion protein for 5 weeks resulted in significant B-cell reduction in both the peripheral blood and spleen. Treated mice developed lower proteinuria, reduced glomerulonephritis and much delayed host death than untreated animals. Thus, BAFF blockade with BAFF-R-IgG4mut protein is an effective strategy to treat B-cell-mediated lupus-like pathology. Moreover, compared with other IgG isotypes with undesired effector functions, mutant IgG4 Fc should prove useful in constructing novel therapeutic reagents to block immune molecule signalling in various diseases.

[Efficacy of hirudin in treating immunoglobulin A nephropathy with hematuria: a randomized controlled trial].

OBJECTIVE: To investigate the curative effects and side effects of hirudin in treating immunoglobulin A nephropathy (IgAN) with hematuria and minimal proteinuria in a short-term. METHODS: Two hundred and sixty-two histologically confirmed cases of IgAN with hematuria and minimal proteinuria from 1998 to 2007 were randomly divided into hirudin-treated group (peroral administration of Maixuekang capsules) and dipyridamole-treated group (peroral administration of dipyridamole). In the two groups, contrast analysis of conformation and counts of erythrocytes in urine, urine protein quantitation in 24 hours, levels of serum creatinine (Scr) and creatinine clearance rate (Ccr), blood lipid, five items of blood clotting and side effects was performed. RESULTS: After six-month treatment, the anisotrophy rate and the counts of erythrocytes in urine, and the urine protein quantitation in 24 hours in hirudin-treated group were decreased distinctly as compared with pre-treatment (P<0.01) and dipyridamole-treated group (P<0.05). On the other hand, Ccr was increased obviously in hirudin-treated group as compared with pre-treatment and dipyridamole-treated group (P<0.01). The blood lipid was also ameliorated in hirudin-treated group, but there was no significant difference. The anticoagulation effect of hirudin was better than dipyridamole (P<0.01). Efficacy assessment showed that the total response rate, complete remission rate and predominance remission rate in hirudin-treated group were higher than those in dipyridamole-treated group. Few side effects were found in both groups, and the rate of adverse reaction in gastrointestinal tract was lower in hirudin-treated group as compared with that in dipyridamole-treated group (P<0.05). CONCLUSION: Compared with dipyridamole, hirudin has superiority in kidney protection and decreasing the anisotrophy rate, counts of erythrocytes in urine and the urine protein.

Urinary neutrophil gelatinase-associated lipocalin (NGAL) is an early biomarker for renal tubulointerstitial injury in IgA nephropathy.

Renal tubulointerstitial injury plays an important role in the development of IgA nephropathy (IgAN), the most common form of glomerulonephritis. Few currently in use biomarkers can sensitively detect the earliest signs of renal tubular injury, hindering our efforts to launch preventive and therapeutic measures for this disorder in a timely manner. Neutrophil gelatinase-associated lipocalin (NGAL) is an acute phase protein that is rapidly released from not only neutrophils but also a variety of cell types upon inflammation and tissue injury. Its small molecular size and protease resistance could render it an excellent biomarker of renal injury in IgAN. In this study, we tested this hypothesis by measuring urinary levels of NGAL, creatinine and N-acetyl-beta-D-glucosaminidase (NAG) in 40 healthy individuals and 70 IgAN patients with various disease severities. The urinary NGAL levels and NGAL/creatinine values were significantly upregulated in Lee grade III IgAN patients, in correlation with progressive glomerular mesangial proliferation and tubulointerstitial injury. Compared with urinary NAG levels, the urinary NGAL levels elevated much more drastically and can be readily detected even in Lee grade II IgAN patients when their NAG levels showed almost no change. Our findings suggest the promising use of urinary NGAL as an early biomarker for tubulointerstitial injury of IgA nephropathy and perhaps other types of renal disease in general.

Delivering PD-1 inhibitory signal concomitant with blocking ICOS co-stimulation suppresses lupus-like syndrome in autoimmune BXSB mice.

BXSB mice spontaneously develop an autoimmune syndrome characterized by hypergammaglobulinemia, autoantibody production, and the development of fatal glomerulonephritis that closely resembles systemic lupus erythematosus (SLE) in humans. While blocking positive T cell co-stimulation has shown effectiveness in preventing the onset of murine lupus, deliberate delivering negative co-stimulation to halt unwanted T and B cell activation has not been tested. We developed a recombinant adenovirus containing the full-length mouse PD-L1 gene (Ad.PD-L1) to engage the immunoinhibitory receptor PD-1 on activated lymphocytes to prevent lupus nephritis in BXSB mice. This strategy was further reinforced by concomitant injection of anti-ICOSL(B7h) mAb to block ICOS-mediated co-stimulation. The combined therapy dramatically delayed the onset of proteinuria, effectively inhibited IgG autoantibody production, and significantly reduced hypercellularity and deposition of IgG in glomeruli, resulting in almost complete amelioration of lupus nephritis in these animals. Our results indicate the therapeutic potential of simultaneous stimulation of PD-1-mediated pathway and blockade of ICOS-B7h co-stimulation in the prevention of human lupus nephritis.

[Effect of p21 on the changes in renal tubular epithelial cells after ischemia/reperfusion injury of kidney].

OBJECTIVE: To investigate the contribution of p21 gene in renal tubular epithelial cells in p21 (+/+) and p21 (-/-) mice of young and old ages at different times after kidney ischemia/reperfusion injury (IRI). METHODS: In p21 (+/+) and p21 (-/-) male mice at the ages of 2 and 12 months the kidneys were made ischemic by clamping the left renal artery for 45 minutes followed by declamping. On 0, 1, 3 and 7 days, 1, 3 and 6 months after reflow, renal tissue was processed for pathological study, determination of proliferating cell nuclear antigen (PCNA), apoptosis and senescence-associated beta-galactosidase (SA-beta-gal) analysis, using hematoxylin and eosin staining, immunohistochemistry, terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick-end labeling (TUNEL), and histochemical staining, respectively. RESULTS: Renal tubule necrosis and cell apoptosis were more severe in p21 (-/-) mice and old mice as compared with p21 (+/+) mice and young mice (both P<0.05), respectively. In young p21 (+/+) mice, occasionally faint staining for SA-beta-gal activity began to appear after 1 month, and significantly increased 3 and 6 months after IRI (P<0.05), but there was no positive staining for SA-beta-gal in the contralateral kidney or both kidneys in p21 (-/-) mice at any time. Another manner of the expression of SA-beta-gal was detected in aged p21 (+/+) mice, as both kidneys showed intensely positive staining for SA-beta-gal at 0 day after IRI, it then subsided notably on 1 day in the IRI kidney (P<0.05), but increased again at 3 months, though still less intense than the contralateral kidney, albeit more intense than the young mice at the same time (P<0.05). Three months after IRI, in both the IRI kidney and the contralateral kidney, positive staining for SA-beta-gal almost reached the same level. On the contrary, only occasional faint staining for SA-beta-gal activity was observed in aged p21 (-/-) mice at any time. No significant difference in positive staining of nuclear PCNA was found between in young and aged p21 (+/+) mice (P>0.05), although the numbers of positively stained nuclear PCNA were more in number in young mice than in aged mice. But in p21 (-/-) mice, significantly more cells were positively stained for PCNA, especially in young mice and in IRI kidneys (P<0.05). Correlation analysis between senescent and apoptotic cells in aged mice made at 1 day after IRI showed striking negative correlation between both of them [p21 (+/+) mice: r=-0.82; P<0.001; p21 (-/-) mice: r=-0.76, P<0.001]. CONCLUSION: IRI can promote the senescence process of normal tubular cells, and can accelerate death (necrosis and apoptosis) process of senescent tubular cells. p21 gene may play an important role in the senescence changes in tubular epithelial cells after kidney ischemia/reperfusion injury.

PD-L1 is expressed by human renal tubular epithelial cells and suppresses T cell cytokine synthesis.

T cell activation is affected by both stimulatory and inhibitory co-signaling. MHC class II-expressing renal tubular epithelial cells (TEC) can function as APC for T cells. To study the influence of inhibitory ligands on TEC-mediated T cell activation, we examined the expression of programmed death ligand-1 (PD-L1) on human TEC line HK-2 cells, as well as in normal and diseased kidney samples. RT-PCR, FACS, and immunocytochemistry showed that PD-L1 is constitutively expressed on HK-2 cells, and is dramatically upregulated by IFN-gamma. In situ hybridization and immunohistochemical staining revealed constitutive low expression of PD-L1 on proximal tubules at both mRNA and protein levels in normal kidneys, but much higher expression in kidneys with type IV lupus nephritis. In vitro, pretreatment of IFN-gamma-stimulated HK-2 cells with anti-PD-L1 significantly enhanced IL-2 secretion from cocultured, mitogen-activated Jurkat or human peripheral blood T cells. These results suggest that the PD-L1:PD-1 pathway negatively regulates T cell activation by TEC, and may play an inhibitory role in TEC-mediated immune activation and immunopathology in the kidney.

[Expression of monocyte chemoattractant protein-1 in glomerular endothelial cells stimulated by high concentration of glucose].

AIM: To study the expression of monocyte chemoattractant protein-1 (MCP-1) in cultured human glomerular endothelial cells (HUGECs) stimulated by high concentration of glucose. METHODS: The effect of high concentration of glucose on the expression of MCP-1mRNA by HUGECs was detected by in situ hybridization and cell ELISA. The monocyte migration induced by the conditioned media of cultured HUGECs was assayed by a modified Boyden Chamber micropore filtration membrane method. Effects of anti-MCP-1 antibody on monocyte migration was detected as well. RESULTS: The MCP-1 mRNA was only weakly expressed in HUGECs cultured under the condition of low concentration of glucose. Following a stimulation of high concentration of glucose (25 mmol/L), MCP-1 mRNA expression was upregulated from the 8th hour and reached the maximum at the 16th hour. Conditioned medium of cultured HUGECs stimulated with high concentration of glucose had marked chemotaxis for monocytes, which was inhibited by anti-MCP-1 antibody. CONCLUSION: HUGEC stimulated by high glucose may highly express MCP-1, and produce chemotatic factors for monocytes.