Yanbing Li

Effect of intensive insulin therapy on β-cell function and glycaemic control in patients with newly diagnosed type 2 diabetes: a multicentre randomised parallel-group trial

BACKGROUNDnEarly intensive insulin therapy in patients with newly diagnosed type 2 diabetes might improve beta-cell function and result in extended glycaemic remissions. We did a multicentre, randomised trial to compare the effects of transient intensive insulin therapy (continuous subcutaneous insulin infusion [CSII] or multiple daily insulin injections [MDI]) with oral hypoglycaemic agents on beta-cell function and diabetes remission rate.nnnMETHODSn382 patients, aged 25-70 years, were enrolled from nine centres in China between September, 2004, and October, 2006. The patients, with fasting plasma glucose of 7.0-16.7 mmol/L, were randomly assigned to therapy with insulin (CSII or MDI) or oral hypoglycaemic agents for initial rapid correction of hyperglycaemia. Treatment was stopped after normoglycaemia was maintained for 2 weeks. Patients were then followed-up on diet and exercise alone. Intravenous glucose tolerance tests were done and blood glucose, insulin, and proinsulin were measured before and after therapy withdrawal and at 1-year follow-up. Primary endpoint was time of glycaemic remission and remission rate at 1 year after short-term intensive therapy. Analysis was per protocol. This study was registered with ClinicalTrials.gov, number NCT00147836.nnnFINDINGSnMore patients achieved target glycaemic control in the insulin groups (97.1% [133 of 137] in CSII and 95.2% [118 of 124] in MDI) in less time (4.0 days [SD 2.5] in CSII and 5.6 days [SD 3.8] in MDI) than those treated with oral hypoglycaemic agents (83.5% [101 of 121] and 9.3 days [SD 5.3]). Remission rates after 1 year were significantly higher in the insulin groups (51.1% in CSII and 44.9% in MDI) than in the oral hypoglycaemic agents group (26.7%; p=0.0012). beta-cell function represented by HOMA B and acute insulin response improved significantly after intensive interventions. The increase in acute insulin response was sustained in the insulin groups but significantly declined in the oral hypoglycaemic agents group at 1 year in all patients in the remission group.nnnINTERPRETATIONnEarly intensive insulin therapy in patients with newly diagnosed type 2 diabetes has favourable outcomes on recovery and maintenance of beta-cell function and protracted glycaemic remission compared with treatment with oral hypoglycaemic agents.

Sphingosine Kinase 1 Is Overexpressed and Promotes Proliferation in Human Thyroid Cancer

Sphingosine kinase 1 (SphK1), an oncogenic kinase, has been previously found to be elevated in various types of human cancer and play a role in tumor development and progression. Nevertheless, the biological and clinical significance of SphK1 in thyroid cancer is largely unknown. Here, we demonstrate that the expression of SphK1 is generally up-regulated in thyroid cancer and that its expression level is correlated with the degree of thyroid malignancy. Silencing SphK1 by specific RNA interference is able to suppress the proliferation of thyroid cancer cells, and SphK1 expression level is strongly associated with the expression of proliferation cell nuclear antigen in thyroid cancer tissues. Of particular note is that depletion of SphK1 results in dephosphorylation of protein kinase B and glycogen synthase kinase-3β and subsequent inactivation of β-catenin-T-cell factor/lymphoid enhancing factor transcriptional activity. Hence, taken together, our study has identified SphK1 as a proproliferative oncogenic kinase, an Akt/glycogen synthase kinase-3β/β-catenin activator, and probably a biomarker for thyroid cancer as well.

Down-Regulation of miR-218-2 and Its Host Gene SLIT3 Cooperate to Promote Invasion and Progression of Thyroid Cancer

CONTEXTnThe functional relationships between intronic microRNAs (miRNAs) and their host genes in thyroid cancer remain unclear. miR-218, a miRNA down-regulated in several kinds of cancers and associated with multiple cancer phenotypes, is transcribed from 2 loci located on chromosomes 4p15.31 (miR-218-1) and 5q35.1 (miR-218-2) within the introns of SLIT2 and SLIT3, respectively.nnnOBJECTIVEnThe aim of our work was to investigate the expression and the roles of miR-218-1 and miR-218-2, as well as their host genes SLIT2 and SLIT3 in thyroid carcinogenesis.nnnDESIGNnThe expression of miR-218-1 and miR-218-2, as well as their host genes SLIT2 and SLIT3, in a panel of normal and neoplastic human thyroid tissues was assessed by quantitative RT-PCR. We restored the expression of miR-218-2 and SLIT3 in thyroid cancer cells and evaluated their effects on cell invasion, migration, and proliferation.nnnRESULTSnWe found that miR-218-2 and its host gene SLIT3 were down-regulated concomitantly in thyroid cancer. Synergistic inhibitory effects of miR-218-2 with SLIT3 on thyroid cancer cell invasion, migration, and proliferation were observed. Moreover, the effects of miR-218-2 on thyroid cancer cells were due, at least partially, to targeting PDGFRA and PLCG1.nnnCONCLUSIONSnThese results implicate the involvement of miR-218-2 and its host gene SLIT3 in thyroid cancer cell invasion, migration, and proliferation. Our findings highlight the functional associations of intronic miRNAs and their host genes in thyroid carcinogenesis.

Attitudes Toward Diabetes Affect Maintenance of Drug-Free Remission in Patients With Newly Diagnosed Type 2 Diabetes After Short-Term Continuous Subcutaneous Insulin Infusion Treatment

OBJECTIVE Short-term intensive insulin treatment in patients with newly diagnosed type 2 diabetes can improve β-cell function and insulin sensitivity, which results in long-term remission without need for further antidiabetes medication. Patient attitudes toward their disease were assessed using the Diabetes Care Profile (DCP) tool to evaluate the potential impact on maintaining long-term remission. RESEARCH DESIGN AND METHODS Newly diagnosed patients with type 2 diabetes were recruited and treated with continuous subcutaneous insulin infusion (CSII) for 2–3 weeks. They were also invited to participate in diabetes self-management intervention during hospitalization and complete a DCP questionnaire on attitudes toward diabetes at baseline and 3, 6, and 12 months after suspension of CSII. RESULTS Near normoglycemia was achieved by 118 patients after short-term CSII, with 65 remaining in drug-free remission for >1 year. They had significantly better glycemic control and greater restoration of acute insulin response after CSII as well as higher educational attainment compared with patients experiencing relapse. They also achieved higher scores in positive attitude, (belief in) importance of care, care ability, self-care adherence, and less negative attitude. Differences between the two groups became greater over time. Cox proportional hazards model analysis indicated that greater self-care adherence (hazard ratio 0.184, P < 0.001) and homeostasis model assessment of insulin resistance before treatment (0.854, P = 0.053) were independent predictors for long-term remission, whereas elevated 2-h postprandial plasma glucose after CSII (1.156, P = 0.015) was a risk factor for relapse. CONCLUSIONS Attitudes toward diabetes affect long-term drug-free remission in newly diagnosed patients with type 2 diabetes after short-term CSII.

Hyperinsulinaemic hypoglycaemia associated with a heterozygous missense mutation of R1174W in the insulin receptor (IR) gene

Backgroundu2002 Mutations in the insulin receptor (IR) gene are known to cause severe insulin resistance. Although clinical features due to a mutation can be diverse, hypoglycaemia is found in some cases. A family with a female proband diagnosed with type A insulin resistance syndrome was studied. Clinical characteristics were compared with the Arginine1174Glutamine (R1174N) mutation reported in the literature.

PSAT1 regulates cyclin D1 degradation and sustains proliferation of non‐small cell lung cancer cells

Multiple nodes in the one‐carbon metabolism pathway play important regulatory roles in cancer cell growth and tumorigenesis. The specific biological functions of metabolic enzymes in regulating the signaling pathways that are associated with tumor cell growth and survival, however, remain unclear. Our current study found that phosphoserine aminotransferase 1 (PSAT1), an enzyme catalyzing serine biosynthesis, was significantly up‐regulated in non‐small cell lung cancer (NSCLC) and was involved in the regulation of E2F activity. Loss‐ and gain‐of‐function experiments demonstrated that PSAT1 promoted cell cycle progression, cell proliferation and tumorigenesis. Mechanistic study suggested that elevated PSAT1 led to inhibition of cyclin D1 degradation and subsequently an alteration in Rb‐E2F pathway activity, which in turn enhanced G1 progression and proliferation of NSCLC cells. Moreover, phosphorylation of cyclin D1 at threonine 286 by GSK‐3β was required for PSAT1‐induced blockage of cyclin D1 degradation. We also found that the activity of p70S6K mediated the effects of PSAT1 on GSK‐3β phosphorylation and cyclin D1 degradation. We further identified that PSAT1 was over‐expressed in NSCLC and predicted poor clinical outcome of patients with the disease. Correlation analysis showed that PSAT1 expression positively correlated with the levels of phosphorylated GSK‐3β, cyclin D1 and phosphorylated Rb in NSCLC primary tumors. These findings uncover a mechanism for constitutive activation of E2F via which unrestrained cell cycle progression occurs in NSCLC and may represent a prognostic biomarker and therapeutic target.

Fufang Xue Shuan Tong capsules inhibit renal oxidative stress markers and indices of nephropathy in diabetic rats

Fufang Xue Shuan Tong (FXST) capsules, a traditional Chinese medicine, have been used to treat diabetic nephropathy for many years. FXST has been shown to attenuate elevated levels of oxidative stress in the retina of diabetic rats. However, whether FXST protects kidneys through the same mechanism(s) remains unclear. In this study, diabetes was induced in rats by administration of a high-fat diet and low-dose streptozotocin. Rats were administered low (450 mg/kg/day), middle (900 mg/kg/day) or high (1800 mg/kg/day) doses of FXST orally for 3 months. Another group was administered 50 mg/kg/day orally for the same period. The results indicated that all doses of FXST reduced urinary protein excretion and creatinine clearance and ameliorated the diabetic nephropathy-related mesangial matrix expansion. However, only middle and high doses of FXST prevented glomerular hypertrophy in diabetic rats, and the high dose showed the greatest inhibitory effect with regard to mesangial matrix expansion. Furthermore, superoxide dismutase activities were significantly elevated, whereas malondialdehyde levels were significantly reduced in the renal cortex following FXST treatment. The kidney-protective role of FXST is not inferior to that of captopril, one of the most commonly used drugs for the treatment of diabetic nephropathy. In conclusion, FXST retards the progression of diabetic nephropathy, while high-dose FXST shows the most prominent effect in counteracting the pathological changes of diabetic nephropathy. The renoprotective action of FXST is induced by the reduction of oxidative stress in diabetic nephropathy.

The Akt/FoxO1/p27 pathway mediates the proliferative action of liraglutide in β cells

Numerous studies have shown that liraglutide, a modified form of human glucagon-like peptide-1 (GLP-1), increases β-cell mass. However, the underlying molecular mechanisms remain unclear. In the present study, we investigated the role of Akt/FoxO1/p27 signaling in liraglutide-induced β-cell proliferation. INS-1 rat insulinoma cells were exposed to two different concentrations of liraglutide. MTT assay was performed to evaluate β-cell proliferation. The expression of Akt/FoxO1/p27 was detected by quantitative real-time PCR and Western blotting. The results revealed that in comparison to the non-treatment group, stimulating INS-1 cells with 10 and 100 nM liraglutide caused β-cell proliferation to be significantly enhanced. The mRNA levels of p27 in INS-1 cells declined upon treatment with liraglutide compared to the non-treatment group. Western blot analysis revealed that the phosphorylation of Akt and FoxO1 was markedly elevated following exposure to liraglutide. Moreover, LY294002, a phosphatidylinositol 3-kinase (PI-3K) inhibitor, significantly abrogated liraglutide-induced effects. Therefore, we conclude that liraglutide increased the β-cell mass by upregulating β-cell proliferation and that the proliferative action of liraglutide in β cells was mediated by activation of PI-3K/Akt, which resulted in inactivation of FoxO1 and decreased p27.

Serum Insulin-like growth factor-1 levels of healthy adults in southern China

It is to establish the normal range and investigate the distribution characteristics of serum Insulin-like growth factor-1 (IGF-1) for healthy adults in southern China. IGF-1 levels of 515 healthy adults (254 males and 261 females) were measured by automated chemiluminescence immunoassay. The subjects were strictly selected healthy volunteers, aged 20 to 84 years old, with equal five year intervals and without abnormal conditions that impacted IGF-1 levels. The reference ranges were calculated using the smooth centile curves of the LMS method (L: coefficient of skewness, M: median, S: coefficient of variation). IGF-1 declined with aging in adults. There were statistically significant differences for the IGF-1 levels between men and women in some subgroups of age. Gender differences varied depending on the age. Middle-aged females had higher IGF-1 whilst elder females had lower IGF-1. The statistical differences were seen in three subgroups of age between this study and a German cohort that is the reference range for the laboratory test kit. Here, the age- and gender-specific normal range was established for Chinese adults. A Z Score of IGF-1 for an individual could be obtained via the LMSchartmaker application, which standardized IGF-1 research worldwide.