Blockade of the OX40/OX40L pathway and induction of PD-L1 synergistically protects mouse islet allografts from rejection

Background OX40/OX40 ligand （OX40/OX40L） and programmed death-1/programmed death ligand-1 （PD-1/PD-L1） co- stimulator/signals play important roles in T cell-induced immune responses. The aim of this study was to investigate the roles of OX40/OX40L and PD-1/PD-L1 costimulatory pathways in mouse islet allograft rejection. Methods Lentiviral vectors containing OX40L siRNA sequences and an adenovirus vector containing the PD-L1 gene were constructed. The streptozotocin-induced model of diabetes was established in C57BL/6 （H-2b） mice. Diabetic C57BL/6 mice were randomly allocated into five groups： group 1, untreated control; group 2, Ad-EGFP treatment; group 3, Ad-PD-L1 treatment; group 4, OX40L-RNAi-LV treatment; group 5, OX40L-RNAi-LV combined with Ad-PD-L1 treatment. Lentiviral vector and the adenovirus vector were injected, singly or combined, into the caudal vein one day before islet transplantation. The islets of DBA/2 （H-2d） mice were transplanted into the renal subcapsular space of the diabetic recipients. Recipient blood glucose and the survival time of the allografts were monitored. Antigen-specific mixed lymphocyte reaction was also evaluated.     

HLA-G expression in the peripheral blood of live kidney transplant recipients

Background The human leukocyte antigen-G (HLA-G) has been considered to be an important tolerogeneic molecule playing an essential role in maternal-fetal tolerance, upregulated in the context of transplantation, malignancy, and inflammation, and has been correlated with various clinical outcomes. The aim of this study was to investigate the clinical relevance of the expression of membrane HLA-G (mHLA-G), intracellular HLA-G (iHLA-G), and soluble HLA-G (sHLA-G) in the peripheral blood of live kidney transplant recipients.

Methods We compared the expression of the three HLA-G isoforms in three groups, healthy donors (n=20), recipients with acute rejection (n=19), and functioning transplants (n=30). Flow cytometry was used to detect the expression of mHLA-G and iHLA-G in the T lymphocytes of peripheral blood from subjects in the three groups. Enzyme-linked immunosorbent assays were used to detect sHLA-G in the plasma from the three groups.

Results There were no significant differences in mHLA-G and intracellular HLA-G among the three groups, but the sHLA-G plasma level was higher in the functioning group than in the acute rejection or healthy group. We found a subset of CD4+HLA-G+ and CD8+HLA-G+ T lymphocytes with low rates of mHLA-G expression in the peripheral blood of kidney transplantation recipients. Intracellular expression of HLA-G was detected in T lymphocytes. However, there was no correlation between acute rejection and the mHLA-G or intracellular HLA-G expression.

Conclusion sHLA-G was the major isoform in the peripheral blood of live kidney transplant recipients and high sHLA-G levels were associated with allograft acceptance.

     

Changes in dendritic cells and dendritic cell subpopulations in peripheral blood of recipients during acute rejection after kidney transplantation

Background Advances in transplantation immunology show that the balance between dendritic cells （DCs） and their subsets can maintain stable immune status in the induction of tolerance after transplantation. The aim of this study was to investigate if DCs and DC subpopulations in recipient peripheral blood are effective diagnostic indicators of acute rejection following kidney transplantation. Methods Immunofluorescent flow cytometry was used to classify white blood cells （WBCs）, the levels of mononuclear cells and DCs （including the dominant subpopulations, plasmacytoid DC （pDC） and myeloid DC （mDC）） in peripheral blood at 0, 1, 7, and 28 days and 1 year after kidney transplantation in 33 patients. In addition, the blood levels of interleukin-10 （IL-10） and IL-12 were monitored before and after surgery. Fifteen healthy volunteers served as normal controls. Patients were undertaking hemodialysis owing to uremia before surgery. Results The total number of DCs, pDC, and mDC in peripheral blood and the pDC/mDC ratio were significantly lower in patients than controls （P 〈0.05）. Peripheral DCs suddenly decreased at the end of day 1, then gradually increased through day 28 but remained below normal levels. After 1 year, levels were higher than before surgery but lower than normal. The mDC levels were higher in patients with acute rejection before and 1 day after surgery （P 〈0.005）. There was no significant difference in IL-10 and IL-12 levels between patients with and without acute rejection. Conclusion The changes in DCs and DC subpopulations during the acute rejection period may serve as effective markers and referral indices for monitoring the immune state, and predicting rejection and reasonably adjusting immunosuppressants.     

Overexpression of interleukin-l7 in tumor-associated macrophages is correlated with the differentiation and angiogenesis of laryngeal squamous cell carcinoma

Background  Interleukin-l7 (IL-17), which exerts strong pro-inflammatory effects, has emerged as an important mediator in inflammation-associated cancer. The aim of this study was to clarify the relationship between IL-17 and tumor associated macrophages (TAMs), and the correlation of the microvessel density in the development of laryngeal squamous cell carcinoma (LSCC).

Methods  Histopathological observations and immunohistochemistry staining for IL-17, CD68, and CD34 were performed on 72 specimens (32 cases of LSCC, 20 cases of adjacent tissues of carcinoma as controls, and 20 cases of chronic hypertrophic laryngitis). Double immunohistochemical staining was done to determine which cells expressed IL-17. Real-time quantitative PCR determined the mRNA expression of IL-17. ELISA was used to detect the expression of the serum level of IL-17 in the three groups.

Results  The inflammation response had increased in LSCC. Overexpression of IL-17 and CD68 protein were seen in LSCC (P <0.01). The expression of IL-17 was different between well and poorly differentiated LSCC (P <0.01). The IL-17 expressing cells were mainly located in macrophages (CD68⁺/IL17⁺) as demonstrated by double immunohistochemical staining. IL-17 expression significantly correlated with high microvessel density (CD34⁺) in LSCC (P <0.05). Relatively higher mRNA expression levels of IL-17 were seen in LSCC compared to the controls (P <0.05). The serum expression of IL-17 was similar among the three groups (P >0.05).

Conclusion  IL-17 was expressed by TAMs, and IL-17 may significantly correlate to the differentiation and angiogenesis in the development of LSCC.

     

Immature CD4+ dendritic cells conditioned with donor kidney antigen prolong renal allograft survival in rats

Background  Allogeneic transplant rejection is currently a major problem encountered during organ transplantation. The dendritic cell (DC) is the most effective powerful known professional antigen-presenting cell, and recent studies have found that DCs can also induce immune tolerance, and avoid or reduce the degree of transplant rejection. The aim of this study was to evaluate the effect of transfused immature CD4⁺ DCs on renal allografts in the rat model.

Methods  In this study, we induced CD4⁺ immature DCs from rat bone marrow cells by a cytokine cocktail. The immature CD4⁺ DCs were identified by morphological analysis and then the suppressive activity of these cells conditioned with donor kidney antigen was evaluated in vitro and in vivo.

Results  Immature CD4⁺ DCs conditioned with donor kidney antigen possessed immunosuppressive activity in vitro and they were able to prolong renal transplant survival in an allograft rat model in vivo.

Conclusions  Our study provides new information on efficacious renal transplantation, which might be useful for understanding the function of immature CD4⁺ DCs in modulating renal transplant rejection and improving clinical outcome in future studies.

     

Effects of glucose and insulin on the H9c2 （2-1） cell proliferation may be mediated through regulating glucose transporter 4 expression

Background The change of glucose transporter 4 （GLUT4） expression could influence glucose uptake in the myocardial cells and then effect myocardial metabolism, which maybe one of the factor for the diabetes cardiovascular disease. This study aimed to explore the influence of glucose and insulin at different concentrations on H9c2 （2-1） cell proliferation and its GLUT4 expression in vitro, and evaluate the correlation between myocardial cells proliferation and GLUT4 expression. This might be helpful for understanding the relationship between glucose metabolism and cardiovascular disease. Methods According to glucose concentrations in culture medium, cultured H9c2 rat myocardial cells were divided into five groups： control group （NC, glucose concentration 5.0 mmol/L）, low glucose group （LG, glucose concentration 0.1 mmol/L）, high glucose group 1 （HG1, glucose concentration 10 mmol/L）, high glucose group 2 （HG2, glucose concentration 15 mmol/L）, high glucose group 3 （HG3, glucose concentration 20 mmol/L）. Then according to different insulin concentrations in culture medium, each group was further divided into two subgroups： normal insulin subgroup （INSc, insulin concentration 3.8 mU/L）, high insulin subgroup （INSh, insulin concentration 7.6 mU/L）. H9c2 （2-1） cells were cultured for 1, 2, 3 days, the proliferation of cells were assayed by cell counting Kit-8 assay, the expressions of GLUT4 mRNA and protein were detected with RT-PCR and Western Blotting technique, and the relation between myocardial cells proliferation and GLUT4 expression was evaluated.     

肾移植后外周血单个核细胞中Foxp3 mRNA的表达

目的:研究外周血单个核细胞中Foxp3 mRNA表达水平与同种异体肾移植术后急性排斥反应及慢性移植肾肾病发生的关系。方法:应用实时荧光定量聚合酶链式反应（RT-PCR)的方法检测16例肾移植术后急性排斥患者、8例慢性移植肾肾病患者、8例移植后肾功能正常者、8例尿毒症患者和8例正常人的新鲜外周血单个核细胞中Foxp3 mRNA的表达水平,比较各组的差异及其与急性排斥反应和慢性移植肾肾病发生的关系。结果:急性排斥反应患者外周血中Foxp3 mRNA表达水平低于慢性移植肾肾病患者,差异有统计学意义（P<0.01);慢性移植肾肾病患者外周血中Foxp3 mRNA表达水平明显低于正常人、终末期肾病患者和肾移植后肾功能正常患者,差异有统计学意义（P<0.01);正常人、终末期肾病患者和肾移植后肾功能正常患者之组间Foxp3 mRNA表达水平无显著差异（P>0.05)。结论:外周血中Foxp3 mRNA表达水平可以反应移植肾的功能状态,其可能成为早期诊断移植后急性排斥反应和慢性移植肾肾病的一个无创指标。     

创伤骨科患者创伤严重程度和血浆D二聚体水平的相关分析

Background  The correlation between the plasma D-dimer level and deep vein thrombosis has not been conclusive in various studies. The aim of this research was to study the relationship between plasma D-dimer levels and the severity of orthopedic trauma by retrospective examination of orthopedic trauma cases.

Methods  Clinically acute trauma and non-acute trauma patients were selected and their plasma D-dimer levels were measured. Plasma D-dimer levels in patients of these two groups were compared. The relationship between the plasma D-dimer level and the severity of the trauma was also studied.

Results  There were 548 cases in the acute trauma group and 501 cases in the non-acute trauma group. The levels of plasma D-dimer were significantly higher in the acute trauma group than in the non-acute trauma group (P <0.01). In the acute trauma group, the correlation between the D-dimer level and the number of fractures was a positive linear correlation (r=0.9532).

Conclusions  Elevated plasma D-dimer is common in trauma patients. The D-dimer level and the number of fractures in the trauma patients are closely correlated. D-dimer is not only an indicator for the diagnosis of deep vein thrombosis and pulmonary embolus, but also an indicator of the severity of trauma in acute trauma patients.

     

Efficacy of the long-acting octreotide formulation in patients with thyroid-stimulating hormone-secreting pituitary adenomas after incomplete surgery and octreotide treatment failure

Background  Little information about the current management of patients with thyroid-stimulating hormone (TSH)-secreting pituitary adenomas or about the usefulness of the somatostatin analogue octreotide was contained in the literature. This study aimed to report the efficacy and safety of the long-acting octreotide formulation in patients with TSH-secreting pituitary adenomas after incomplete surgery and octreotide treatment failure. 

Methods  Fifteen patients with TSH-secreting pituitary adenomas (8 men and 7 women), who previously underwent incomplete surgical resection and/or adjuvant radiotherapy (n=12) and failure of octreotide treatment (n=15), followed between 2007 and 2010 in Beijing Tiantan Hospital were included in this study. All patients received 1- to 2-months of the long-acting octreotide formulation treatment after the above combination of treatment. Paired samples t-test was used to analysis the variables.

Results  After two-month duration of the long-acting octreotide formulation treatment, the mean serum free or unbound thyroxine (FT4) ((16.02±1.72) pmol/L) and free triiodothyronine (FT3) ((2.87±0.43) pmol/L) levels of 15 patients significantly decreased compared with those after octreotide-treatment (FT4, (35.36±7.42) pmol/L, P <0.001; FT3, (17.85±7.22) pmol/L, P <0.001). Mean TSH levels stayed in the normal range after the long-acting octreotide formulation treatment ((0.72±0.21) mU/L) and were significantly lower than the pretreatment value ((5.27±1.04) mU/L, P <0.001), post-surgery value ((3.37±0.31) mU/L, P <0.001) and post-octreotide-treatment value ((4.52±0.41) mU/L, P <0.001). In these patients with TSH-secreting pituitary adenomas there was no evidence of tachyphylaxis.

Conclusion  The long-acting octreotide formulation may be a useful and safe therapeutic tool to facilitate the medical treatment of TSH-secreting pituitary adenomas in patients who underwent incomplete surgery or need long-term somatostatin analog therapy.

     

Risk factors for delayed graft function in cardiac death donor renal transplants

Background  Delayed graft function (DGF) is common in kidney transplants from organ donation after cardiac death (DCD) donors. It is associated with various factors. Determination of center-specific risk factors may help to reduce the incidence of DGF and improve the transplantation results. The aim of this study is to define risk factors of DGF after renal transplantation.

Methods  From March 2010 to June 2012, 56 cases of recipients who received DCD kidneys were selected. The subjects were divided into two groups: immediate graft function (IGF) and DGF groups. Transplantation factors of donors and recipients as well as early post-transplant results of recipients were compared between the two groups.

Results  On univariate analysis, preoperative dialysis time of recipients (P <0.001), type of dialysis (P=0.039), human leucocyte antigen (HLA) mismatch sites (P <0.001), the cause of brain death (P=0.027), body mass index (BMI) of donors (P <0.001), preoperative infection (P=0.002), preoperative serum creatinine of donors (P <0.001), norepinephrine used in donors (P <0.001), cardiopulmonary resuscitation (CPR) of donors (P <0.001), warm ischemia time (WIT) (P <0.001) and cold ischemia time (CIT) (P <0.001) showed significant differences. Recipients who experienced DGF had a longer hospital stay, and higher level of postoperative serum creatinine.

Conclusion  Multiple risk factors are associated with DGF, which had deleterious effects on the early post-transplant period.

     

Effect and mechanism of tacrolimus on melanogenesis on A375 human melanoma cells

Background Topical tacrolimus has been used for vitiligo as a common treatment option for more than ten years while the underlying mechanism is still uncertain.The aim of this study was to investigate the direct effects of tacrolimus on the melanogenesis and migration on human A375 melanoma cells.The expression of c-KIT mRNA and protein of human A375 cells were also investigated.Methods The cultured A375 human melanoma cells were randomly assigned to control and tacrolimus treatment groups （10,102,103and 104 nmol/L）.The cell proliferation was measured with Cell Counting Kit-8 assays.Melanin content was measured with NaOH method.Transwell migration assay was used to measure cell migration.The expression of c-KIT mRNA and protein were measured with real-time fluorescence quantitative polymerase chain reaction and immunohistochemistry respectively.Results The cell proliferation of the 103 and 104 nmol/L tacrolimus groups were significantly lower （0.666±0.062 and 0.496±0.038） as compared with the control （0.841±0.110,P 〈0.05）.The mean melanin content in all groups treated with different concentration of tacrolimus （10,102,103,104 nmol/L） increased compared with the control group （P 〈0.05）.Dosedependent increase in cell migration were seen in all tacrolimus-treated groups （P 〈0.01）.The expression of c-KIT mRNA level in A375 cells exposed to tacrolimus （103and 104 nmol/L） had significantly increased by 3.03-fold and 3.19-fold respectively compared with the control （P 〈0.05）.Conclusions Although tacrolimus had no effects on cell proliferation on A375 human melanoma cells,it could increase the melanin content and cell migration.The expression of c-KIT mRNA and protein increased dose-dependently in tacrolimus-treated groups as compared with the control.Our study demonstrated that tacrolimus could enhance the melanogenesis and cell migration on A375 cells.     

Effect of anterior nucleus of thalamus stimulation on glucose metabolism in hippocampus of epileptic rats

Background  Electrical stimulation of the anterior nucleus of the thalamus (ANT) appears to be effective against seizures. In this study, we investigated changes in glucose metabolism during high-frequency stimulation of ANT in epileptic rats.

Methods  Three groups of rats were used: (1) a stimulation group (n=12), (2) a sham stimulation group (n=12) with seizures induced by stereotactic administration of kainic acid (KA), and (3) a control group (n=12) with sham surgery. Concentric bipolar electrodes were stereotaxically implanted unilaterally in the ANT. High-frequency stimulation was performed in each group except the sham stimulation group. Microdialysis probes were lowered into the CA3 region of the hippocampus unilaterally but bilaterally in the stimulation group. The concentrations of glucose, lactate, and pyruvate in dialysate samples were determined by an ISCUS microdialysis analyzer.

Results  The extracellular concentrations of lactate and lactate/pyruvate ratio (LPR) of epileptic rats were significantly higher than in control rats (P=0.020, P=0.001; respectively). However, no significant difference in the concentration of glucose and pyruvate was found between these groups (P >0.05). Electrical stimulation of ANT induced decreases in lactate and LPR in the ipsilateral hippocampus (KA injected) of the stimulation group (P <0.05), but it did not influence the glucose metabolism in the contralateral hippocampus (P >0.05).

Conclusions  This study demonstrated that the glycolysis was inhibited in the ipsilateral hippocampus of epileptic rats during electrical ANT stimulation. These findings may provide useful information for better understanding the mechanism of ANT-deep brain stimulation.

     

Epicardial radiofrequency ablation for left ventricular aneurysm related ventricular arrhythmias during off-pump coronary artery bypass surgery

Background  Left ventricular aneurysm (LVA) is one of the serious complications after acute myocardial infarction. We attempted to evaluate the preliminary efficacy of LVA repair combined with epicardial radiofrequency ablation for ventricular arrhythmia during off-pump coronary artery bypass grafting (OPCAB).

Methods  From June 2009 to April 2011, 31 patients with LVA had angina symptoms and ventricular arrhythmia. In all patients, circular and cross-shaped radiofrequency epicardial ablations were performed using unipolar ablation pen along the border between the aneurysm wall and normal cardiac tissue and in the central zone of the aneurysms, followed by a linear placation of ventricular aneurysms on beating heart.

Results  All the patients showed complete recovery. The average number of grafted vessels was 2.7±1.3. Intraoperative examinations revealed that the ventricular arrhythmia was effectively controlled by radiofrequency ablation. All cases had been followed up for one year. Holter monitoring revealed a significant reduction in ventricular arrhythmias (P <0.05). Echocardiography showed significant increase in left ventricular ejection fraction (P <0.05) and decrease in left ventricular end-diastolic diameter (P <0.05).

Conclusions  For patients with ventricular aneurysm and preoperative malignant arrhythmia, aneurysm repair plus epicardial radiofrequency ablation in OPCAB was found to be an effective and feasible therapeutic technique. However, medium- to long-term therapeutic efficacy of this method remains to be determined by future studies and observations.

     

Decreased hepatic glucose production in obese rats by dipeptidyl peptidase-IV inhibitor sitagliptin

Background  Dipeptidyl peptidase-IV (DPP-4) inhibitors are now used to improve postprandial glycemic control in type 2 diabetes. However, their effects on hepatic glucose production (HGP) in obesity are not clear. This study was designed to test the hypothesis that gluconeogenesis and HGP can be modulated by DPP-4 inhibitors in obesity.

Methods  Sprague Dawley male rats were divided into four groups, each on a different diet: general rat chow, n=10 (G); G+sitagliptin, n=10; high fat chow (obesity), n=10 (55% fat calories, HFO); HFO+sitagliptin, n=10. After 10 weeks, the rats were fasted overnight and glucose metabolism was determined using 3-³H-glucose and ¹⁴C-glycerol as tracers.

Results  Glycerol rate of appearance (P <0.00001), plasma glycerol (P <0.05) and free fatty acid (FFA) (P <0.05) concentrations, and HGP (P <0.05) were decreased in HFO+sitagliptin group compared with HFO group, but there was no significant difference between G and G+sitagliptin groups (P >0.05). Gluconeogenesis in HFO group was five times of that in G rats (P <0.01), but was significantly declined in HFO+sitagliptin group (P <0.0001).

Conclusions  Gluconeogenesis and HGP were inhibited by sitagliptin in high fat-induced obese rats due to decreased glycerol availability, which was a result of reduced glycerol release from adipose tissues. The finding suggests that sitagliptin is potentially useful for controlling fasting glucose in obesity, thereby delaying or preventing the development of diabetes.

     

Comparison of clinical curative effect between open surgery and endovascular repair of abdominal aortic aneurysm in China

Objective   To compare clinical curative effects of open surgery (OS) or endovascular repair (EVAR) for patients with abdominal aortic aneurysm (AAA) in China.

Data sources  We performed a comprehensive search of both English and Chinese literatures involving case studies on retrograde OS or EVAR of AAA in China from January 1976 to December 2010.

Study selection  According to the inclusion criteria, 76 articles were finally analyzed to compare patient characteristics, clinical success, complications, and prognosis.

Results  We analyzed a total of 2862 patients with 1757 undergoing OS (OS group) and 1105 undergoing EVAR (EVAR group). There was no significant difference in the success rate of the procedures. Operative time, length of ICU stay, fasting time, duration of total postoperative stay, blood loss, and blood transfusion requirements during the procedure were significantly lower in the EVAR group. A 30-day follow up revealed more cardiac, renal, pulmonary, and visceral complications in the OS group (P <0.01). Low-limb ischemia, however, was more common in the EVAR group (P <0.05). The 30-day mortality rate, including aorta-related and non-aorta related mortality, was significantly lower in the EVAR group (P <0.01). In the follow-up period, there were more patients with occlusions of artificial vessel and late endoleak in the EVAR group (P <0.01). The overall late mortality rate was higher in the OS group (P <0.01), especially non-aorta-related late mortality and mortality during the fourth to the sixth year (P <0.01).

Conclusions  EVAR was safer and less invasive for AAA patients. Patients suffered fewer complications and recovered sooner. However, complications such as artificial vessel occlusion, low-limb ischemia, and endoleak were common in EVAR. Clinicians should carry out further research to solve these complications and improve the efficacy of EVAR.

     

Serum major-histocompatibility-complex class I-related chain A antibody detection for the evaluation of graft dysfunction in renal allograft recipients

Background  In addition to the well-known antibodies against human leukocyte antigens (HLA)-induced kidney-graft rejection, polymorphic major-histocompatibility-complex (MHC) class I-related chain A (MICA) antigens can elicit antibodies and have been suggested to play a role in the antibody-mediated allograft rejection (AMR). We carried out a prospective study of MICA antibodies in post-renal transplant patients to determine the association between MICA antibodies, C4d staining, histological features, and graft outcome.

Methods  We tested 52 patients who had biopsy results due to graft dysfunction. The MICA antibodies in concurrent sera were determined by Luminex. All patients were followed up for one year after renal biopsy. The influence of antibody production on the function of graft was analyzed.

Results  Antibodies against MICA were positive in 15 out of the 52 patients (28.9%). The presence of MICA antibodies was associated with renal-allograft deterioration. During one-year follow-up, the estimated glomerular filtration rate (eGFR) decreased (24.0±3.4)% among recipients with anti-MICA antibodies. However, among recipients without anti-MICA antibodies, the eGFR has declined only (8.4±3.0)% (P=0.017). The association between C4d staining, histological features and MICA antibody production was found no significant difference.

Conclusion  Besides anti-HLA antibodies, the presence of post-transplant MICA antibody is associated with poor graft outcome and increases the risk of graft failure.

     

Endoplasmic reticulum stress is involved in podocyte apoptosis induced by saturated fatty acid palmitate

Background  Podocyte apoptosis is recently indicated as an early phenomenon of diabetic nephropathy. Pancreatic b-cells exposed to saturated free fatty acid palmitate undergo irreversible endoplasmic reticulum (ER) stress and consequent apoptosis, contributing to the onset of diabetes. We hypothesized that palmitate could induce podocyte apoptosis via ER stress, which initiates or aggravates proteinuria in diabetic nephropathy.

Methods  Podocyte apoptosis was detected by 4¢,6-diamidio-2-phenylindole (DAPI) stained apoptotic cell count and Annexin V-PI stain. The expressions of ER molecule chaperone glucose-regulated protein 78 (GRP78), indicators of ER-associated apoptosis C/EBP homologous protein (CHOP), and Bcl-2 were assayed by Western blotting and real-time PCR. GRP78 and synaptopodin were co-localized by immunofluorescence stain.

Results  Palmitate significantly increased the percentage of cultured apoptotic murine podocytes time-dependently when loading 0.75 mmol/L (10 hours, 13 hours, and 15 hours compared with 0 hour, P <0.001) and dose-dependently when loading palmitate ranging from 0.25 to 1.00 mmol/L for 15 hours (compared to control, P <0.001). Palmitate time-dependently and dose-dependently increased the protein expression of GRP78 and CHOP, and decreased that of Bcl-2. Palmitate loading ranging from 0.5 to 1.0 mmol/L for 12 hours significantly increased mRNA of GRP78 and CHOP, and decreased that of Bcl-2 compared to control (P <0.001), with the maximum concentration being 0.75 mmol/L. Palmitate 0.5 mmol/L loading for 3 hours, 8 hours, and 12 hours significantly increased mRNA of GRP78 and CHOP, and decreased that of Bcl-2 compared to 0 hour (P <0.001), with the maximum effect at 3 hours. Confocal microscopy demonstrated that GRP78 expression was significantly increased when exposed to 0.5 mmol/L of palmitate for 8 hours compared to control.

Conclusion  Palmitate could induce podocyte apoptosis via ER stress, suggesting podocyte apoptosis and consequent proteinuria caused by lipotoxic free fatty acid could be ameliorated by relief of ER stress.