Xiaopei Cao

Downregulation of Bcl-2 Expression by miR-34a Mediates Palmitate-Induced Min6 Cells Apoptosis

Recent studies have demonstrated that the expression of miR-34a is significantly upregulated and associated with cell apoptosis in pancreatic β-cell treated with palmitate. Nevertheless, the underlying detailed mechanism is largely unknown. Here, we showed that miR-34a was significantly induced in Min6 pancreatic β-cell upon palmitate treatment. Elevated miR-34a promoted Min6 cell apoptosis. Intriguingly, ectopic expression of miR-34a lowered the expression of Bcl-2, an antiapoptotic protein. Luciferase reporter assay indicated the direct interaction of miR-34a with the Bcl-2 3′-UTR. Moreover, downregulated expression of Bcl-2 induced by palmitate could be restored by inhibition of miR-34a. We conclude that direct suppression of Bcl-2 by miR-34a accounts for palmitate-induced increased apoptosis rate in pancreatic β-cell.

Bezafibrate enhances proliferation and differentiation of osteoblastic MC3T3-E1 cells via AMPK and eNOS activation

Aim:To investigate the effects of bezafibrate on the proliferation and differentiation of osteoblastic MC3T3-E1 cells, and to determine the signaling pathway underlying the effects.Methods:MC3T3-E1 cells, a mouse osteoblastic cell line, were used. Cell viability and proliferation were examined using MTT assay and colorimetric BrdU incorporation assay, respectively. NO production was evaluated using the Griess reagent. The mRNA expression of ALP, collagen I, osteocalcin, BMP-2, and Runx-2 was measured using real-time PCR. Western blot analysis was used to detect the expression of AMPK and eNOS proteins.Results:Bezafibrate increased the viability and proliferation of MC3T3-E1 cells in a dose- and time-dependent manner. Bezafibrate (100 μmol/L) significantly enhanced osteoblastic mineralization and expression of the differentiation markers ALP, collagen I and osteocalcin. Bezafibrate (100 μmol/L) increased phosphorylation of AMPK and eNOS, which led to an increase of NO production by 4.08-fold, and upregulating BMP-2 and Runx-2 mRNA expression. These effects could be blocked by AMPK inhibitor compound C (5 μmol/L), or the PPARβ inhibitor GSK0660 (0.5 μmol/L), but not by the PPARα inhibitor MK886 (10 μmol/L). Furthermore, GSK0660, compound C, or NG-nitro-L-arginine methyl ester hydrochloride (L-NAME, 1 mmol/L) could reverse the stimulatory effects of bezafibrate (100 μmol/L) on osteoblast proliferation and differentiation, whereas MK886 only inhibited bezafibrate-induced osteoblast proliferation.Conclusion:Bezafibrate stimulates proliferation and differentiation of MC3T3-E1 cells, mainly via a PPARβ-dependent mechanism. The drug might be beneficial for osteoporosis by promoting bone formation.

Increased 1,5-anhydroglucitol predicts glycemic remission in patients with newly diagnosed type 2 diabetes treated with short-term intensive insulin therapy.

BACKGROUND Short-term intensive insulin therapy has been shown to induce long-term glycemic remission in patients with newly diagnosed type 2 diabetes. However, predictors of remission are still uncertain. This study was conducted to evaluate whether changes of 1,5-anhydroglucitol (1,5AG) and fructosamine (FA) could be a predictor of remission. SUBJECTS AND METHODS Newly diagnosed drug-naive patients with type 2 diabetes (n = 64) were enrolled. After baseline assessments, continuous subcutaneous insulin infusion (CSII) was administered in all patients until euglycemia was achieved and maintained for another 2 weeks. Patients were subsequently followed monthly for 3 months. 1,5AG and FA were measured before and after therapy and at 1-month follow-up. RESULTS After CSII, A1C and FA decreased from baseline, whereas 1,5AG increased. 1,5AG was higher at 1-month follow-up (11.5 ± 4.1 vs. 6.7 ± 2.8 mg/L, P<0.001), whereas FA was lower (273.1 ± 56.1 vs. 316.2 ± 39.3 μmol/L, P = 0.021) in the remission group. Stepwise logistic regression analysis showed that 1,5AG at 1-month follow-up rather than FA was an independent predictor of remission after adjusting for other confounders (odds ratio 1.56, 95% confidence interval [CI] 1.15-2.12, P = 0.004). The area under the curve of the receiver operating characteristic curve analysis was 0.85 (95% CI 0.75-0.96, P<0.001). The optimal cutoff point for 1,5AG at 1-month follow-up was 8.9 mg/L (specificity, 83.3%; sensitivity, 78.6%). CONCLUSIONS Improvement of 1,5AG predicts maintenance of glycemic remission after intensive insulin therapy in patients with newly diagnosed type 2 diabetes.

Insulin requirement profiles of short-term intensive insulin therapy in patients with newly diagnosed type 2 diabetes and its association with long-term glycemic remission

AIMS To investigate the insulin requirement profiles during short-term intensive continuous subcutaneous insulin infusion (CSII) in patients with newly diagnosed type 2 diabetes and its relationship with long-term glycemic remission. METHODS CSII was applied in 104 patients with newly diagnosed type 2 diabetes. Daily insulin doses were titrated and recorded to achieve and maintain euglycemia for 2 weeks. Measurements of blood glucose, lipid profiles as well as intravenous glucose tolerance tests were performed before and after the therapy. Afterwards, patients were followed up for 1 year. RESULTS Total daily insulin dose (TDD) was 56.6±16.1IU at the first day when euglycemia was achieved (TDD-1). Thereafter, TDD progressively decreased at a rate of 1.4±1.0IU/day to 36.2±16.5IU at the end of the therapy. TDD-1 could be estimated with body weight, FPG, triglyceride and waist circumference in a multiple linear regression model. Decrement of TDD after euglycemia was achieved (ΔTDD) was associated with reduction of HOMA-IR (r=0.27, P=0.008) but not with improvement in β cell function. Patients in the lower tertile of ΔTDD had a significantly higher risk of hyperglycemia relapse than those in the upper tertile within 1 year (HR 3.4, 95%CI [1.4, 8.4], P=0.008). CONCLUSIONS There is a steady decline of TDD after euglycemia is achieved in patients with newly diagnosed type 2 diabetes treated with CSII, and ΔTDD is associated with a better long-term glycemic outcome.

Elevated circulating level of a cytokine, pancreatic-derived factor, is associated with metabolic syndrome components in a Chinese population

Pancreatic‐derived factor (PANDER) is an important factor involved in obesity, glucose intolerance and abnormal lipid metabolism in animals. Nevertheless, the relationship between PANDER and metabolic syndrome (MetS) in humans has not yet been reported.

Effects of Liraglutide Combined with Short-Term Continuous Subcutaneous Insulin Infusion on Glycemic Control and Beta Cell Function in Patients with Newly Diagnosed Type 2 Diabetes Mellitus: A Pilot Study

The objective of this paper is to investigate the effects of liraglutide in combination with short-term continuous subcutaneous insulin infusion (CSII) therapy on glycemic control and beta cell function in patients with newly diagnosed type 2 diabetes mellitus (T2DM). Thirty-nine eligible newly diagnosed T2DM patients were recruited and randomized to receive either of two therapies: short-term CSII alone (CSII alone group) or CSII in combination with liraglutide (CSII + Lira group) for 12 weeks. Blood glucose control, homeostasis model assessment (HOMA) indices, and acute insulin response (AIR) were compared between the two groups. The patients in CSII + Lira group achieved euglycemia with equivalent insulin dosage in shorter time (1 (0) versus 2 (3) days, P = 0.039). HbA1c at the end of study was comparable between two groups (6.3 ± 0.7% versus 6.0 ± 0.5%, for CSII alone group and CSII + Lira group, resp., P = 0.325). The increment of AIR was higher in CSII + Lira group (177.58 (351.57) μU·min/mL versus 58.15 (51.30) μU·min/mL, P < 0.001). However, after stopping liraglutide, its effect on beta cell function disappeared completely. Liraglutide combined with short-term CSII was effective in further improving beta cell function, but the beneficial effects did not sustain after suspension of the therapy.

The utility of HbA1c for screening gestational diabetes mellitus and its relationship with adverse pregnancy outcomes.

AIMS To evaluate the utility of glycated hemoglobin A1c (HbA1c) for screening gestational diabetes mellitus (GDM) and analyze its association with adverse pregnancy outcomes in a cohort of pregnant women. METHODS Women with singleton pregnancies, who completed a 2h oral glucose tolerance test (OGTT) and HbA1c test at gestational week 24-28 were enrolled in this retrospective study. Clinical information was obtained and statistical analyses were performed to assess the diagnostic value of HbA1c for GDM and the association of HbA1c with adverse pregnancy outcomes. RESULTS Of the 1959 pregnant women enrolled in the study, 413 were diagnosed with GDM. A HbA1c cutoff value <4.8% (29mmol/mol) showed adequate sensitivity to exclude GDM (85.0%) but low specificity (31.8%). While HbA1c cutoff value ≥5.5% (37mmol/mol) presented adequate specificity (95.7%) but low sensitivity (14.8%) in diagnosing GDM. Adoption of HbA1c as a screening test for GDM could eliminate the need for an OGTT in 34.7% women in our study, however, with 6.5% being wrongly diagnosed. HbA1c level was significantly associated with the risk of preterm delivery, neonatal hyperbilirubinemia, and neonatal asphyxia. CONCLUSIONS Whether adoption of HbA1c as a screening test for GDM would benefit pregnant women remains to be determined. However, HbA1c might be a useful tool to predict patients at increased risk of several adverse pregnancy outcomes.

Exendin-4 promotes pancreatic β-cell proliferation via inhibiting the expression of Wnt5a

Exendin-4, a glucagon-like peptide-1 receptor agonist, is currently regarded as an effective therapeutic strategy for type-2 diabetes. Previous studies indicated that exendin-4 promoted β cell proliferation. However, the underlying mechanisms remain largely unknown. Recently it was reported that exendin-4 promoted pancreatic β cell proliferation by regulating the expression level of Wnt4. The present study was designed to investigate whether other Wnt isoforms take part in accommodation of β-cell proliferation. We found that exendin-4 promotes the proliferation and suppresses the expression of Wnt5a in INS-1 cell line and C57Bl/6 mouse pancreatic β-cells. Further mechanistic study demonstrated that exendin-4 promoted INS-1 cell proliferation partly through down-regulating the expression of Wnt5a. Furthermore, Wnt5a could induce the activation of calmodulin-dependent protein kinase II in INS-1 cells, thereby decreasing the cellular stable β-catenin and its nuclear translocation, and finally reduce the expression of cyclin D1. In addition, we also found that both of the receptors (Frz-2 and Ror-2) mediated the effect of Wnt5a on β cell line INS-1 proliferation. Taken together, this study suggests that Wnt5a plays a critical role in exendin-4-induced β-cell proliferation, indicating that Wnt5a might be a novel regulator in counterbalance of β cell mass.

A systematic review and meta-analysis of the risk of diarrhea associated with vandetanib treatment in carcinoma patients

Background and purpose Vandetanib is a promising anticancer targeted agent for treating advanced carcinomas, such as non-small-cell lung cancer, small-cell lung cancer, breast cancer, malignant glioma, hepatocellular cancer, and unresectable, locally advanced, or metastatic medullary thyroid cancer. However, diarrhea is a frequently reported adverse event. The incidence of vandetanib-associated diarrhea varies extensively in different study populations and has not been carefully estimated. This systematic review and meta-analysis of clinical trials aims to figure out the overall risks of all-grade and high-grade diarrhea during vandetanib treatment and get a better understanding of its prediction and management. Materials and methods A comprehensive search was performed in EMBASE, PubMed, and Cochrane Library for clinical trials studying vandetanib and diarrhea prior to April 2015. Eligible articles were selected according to the inclusion criteria. Data were extracted to calculate the summary incidence of all-grade and high-grade diarrhea caused by vandetanib treatment. Results Thirteen clinical trials that involved 3,264 patients were included in this meta-analysis. The overall incidences of all-grade and high-grade diarrhea caused by vandetanib treatment were 52.1% (95% confidence interval [CI], 48.3%–55.8%) and 5.6% (95% CI, 4.4%–76.7%), respectively. The risk ratios of the all-grade and high-grade diarrhea for vandetanib arm versus control arm were 1.932 (95% CI, 1.746–2.138; P<0.001) and 3.190 (95% CI, 2.061–4.938; P<0.001), respectively. Studies with small-cell lung cancer demonstrated the highest incidence of all-grade diarrhea (78.85%) and high-grade diarrhea (17.31%), whereas the lowest incidences of all-grade (42.11%) and high-grade (2.67%) diarrhea are seen in patients with hepatocellular carcinoma and non-small-cell lung cancer, respectively. Conclusion Our findings demonstrate that the administration of vandetanib leads to a significantly increased risk of diarrhea, which varies in different carcinoma patients. Early recognition and timely management may be key factors to avoid dose reduction, drug interruption, and drug discontinuation, which is significant to maximize the treatment benefits.

A novel splice site mutation of the PRKAR1A gene, C.440+5 G>C, in a Chinese family with Carney complex

BackgroundCarney complex (CNC) is an extremely rare, multiple endocrine neoplasia syndrome that occurs in an autosomal dominant manner. Mutations in PRKAR1A have been reported to be a common genetic cause of CNC.MethodsIn this study, we reported a Chinese pedigree of CNC that manifests mainly as spotty skin pigmentation and primary pigmented nodular adrenocortical disease. Whole blood samples of this pedigree were collected for DNA/RNA analysis. Polymerase chain reaction (PCR) and reverse-transcription polymerase chain reaction analyses were performed to amplify the 11 exons and adjacent introns of PRKAR1A. Direct sequencing was used to detect the mutation, and DNA from 70 Han Chinese people was extracted and sequenced as a control to estimate the frequency of the identified mutation.ResultsWithin the pedigree, ten patients with CNC were identified, and a novel heterozygous mutation (c.440+5 G>C in intron 4a) was identified in the PRKAR1A gene. PCR amplification of cDNA from the control subjects and patients was performed. Agarose gel electrophoresis showed only one wild-type band in the cDNA corresponding to the former group, whereas an extra band was present in samples from the latter group corresponding to the skipping of exon 4a; this confirms that the variant affects PRKAR1A splicing.ConclusionIn conclusion, the c.440+5 G>C mutation is a new splice site mutation that has not been reported and has the potential to broaden the mutational spectrum of PRKAR1A that is associated with CNC, which would facilitate genetic diagnosis and counseling for CNC.