Inhibition of 11ß-hydroxysteroid dehydrogenase type 1 ameliorates obesity-related insulin resistance.

Excess 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) may be implicated in the development of obesity related metabolic disorders. The present study measured the expression level of 11ß-HSD1 in visceral adipose tissues from 23 patients undergoing abdominal operation. Correlation of 11ß-HSD1 expression with BMI, waist-to-hip ratio (WHR), HOMA-IR, and serum lipids was evaluated by spearman correlation analysis. High-fat diet-induced obese (DIO) rats were orally dosed with BVT.2733 for 4 weeks. Weight, plasma insulin, and lipids were detected at the end of the treatment. The effects of 11ß-HSD1 inhibition on the key insulin-signaling cascade and adipocytokines were measured by western blot and ELISA respectively. 11ß-HSD1 was increased in patients with central obesity, the expression level of which was closely related with WHR (r = 0.5851), BMI (r = 0.4952), and HOMA-IR (r = 0.4637). Obesity related insulin resistance in high-fat DIO rats, as reflected by a marked decrease in IRS-1, IRS-2, GLUT4, and PI3K, could be attenuated by 11ß-HSD1 inhibition. Furthermore, the down-regulation of 11ß-HSD1 could correct the disordered profiles of adipocytokines including adiponectin, IL-6, and TNF-α. These findings indicated that 11ß-HSD1 inhibition can give a potential benefit in reducing obesity and lowering insulin resistance by modulating the insulin-signaling pathway and adipocytokine production.

Sclerosteosis caused by a novel nonsense mutation of SOST in a consanguineous family.

Sclerosteosis, characterized by the hyperostosis of cranial and tubular bones, is a rare autosomal recessive hereditary disorder caused by mutation of SOST gene. Four nonsense mutations of SOST have been identified worldwide. Here, we report two affected siblings who carried a novel nonsense mutation of SOST in a consanguineous family from China. The proband manifested typical symptoms of sclerosteosis, whereas the symptoms were absent in another affected sibling. Two nucleotide substitutions in exon 2 of SOST were identified, c.444_445TC>AA, resulting in a premature stop codon, p.Cys148→Stop. This truncated mutation loses 66 amino acid residues which contain 3 cysteine residues of the cysteine-knot motif, leading to loss of function of SOST. The symptoms of sclerosteosis may be clinically heterogeneous in some patients, even with the same mutation. Our results support the notion that founder effects from the ancestors contribute to the disease onset.

The changes of leukocyte telomere length and telomerase activity after sitagliptin intervention in newly diagnosed type 2 diabetes.

BACKGROUND: In recent years, increasing evidence suggests a potential importance of telomere biology in type 2 diabetes. The aim of this study was to determine whether sitagliptin, a medicine generally used in diabetes, can influence the telomere and telomerase in newly diagnosed type 2 diabetic patients. METHODS: Type 2 diabetic patients (T2D, n = 38) and non-diabetic subjects (control, n = 31) were randomly selected from the outpatient of Tongji Hospital, Tongji Medical College, Huazhong university of Science and Technology. Leukocyte telomere length ratio was measured using a quantitative polymerase chain reaction and was analysed. Telomerase activity was measured by polymerase chain reaction enzyme-linked immunosorbent assay method. Peripheral insulin resistance (homeostasis model assessment) was calculated from fasting plasma glucose and fasting plasma insulin. RESULTS: Telomere length of the type 2 diabetic patients (1.58 ± 0.57) was significantly shorter than those of control subjects (3.98 ± 0.90) and was significantly elongated after intervention by sitagliptin. There was no significant difference between the T2D and control group in telomerase activity, and the treatment of sitagliptin in T2D group showed no significant effect on the telomerase activity. CONCLUSIONS: In type 2 diabetes patients, leukocyte telomere length is significantly reduced, whereas the telomerase activity seems less influenced. Sitagliptin might protect ß-cells in the pancreas by elongating the telomere length.

Glargine insulin/gliclazide MR combination therapy is more effective than premixed insulin monotherapy in Chinese patients with type 2 diabetes inadequately controlled on oral antidiabetic drugs.

BACKGROUND: The aim of this study is to compare the efficacy and safety of once-daily insulin glargine plus gliclazide modified release combination therapy versus twice-daily premixed insulin monotherapy in Chinese type 2 diabetic patients insufficiently controlled by oral antidiabetic agents. METHODS: In a 12-week, multicenter, randomized, parallel-group clinical trial, patients with poor glycaemic control (fasting plasma glucose ≥ 7.0 mmol/L and 7.5% < haemoglobin A1c ≤ 10%) on oral antidiabetic drugs were randomized to the treatment groups for combination therapy (n = 52) or monotherapy (n = 53). Continuous glucose monitoring was carried out over two 72-h periods, at the beginning and the end of the study, and the data were used to calculate the 24-h mean blood glucose, mean amplitude of glycaemic excursions, standard deviation of blood glucose, and the mean of daily differences. RESULTS: The mean haemoglobin A1c decrease from baseline to study end was significant for both treatment groups (combination therapy: -1.23 ± 0.92%; insulin monotherapy: -1.02 ± 1.04%); moreover, the combination therapy group showed a significantly more robust haemoglobin A1c decrease (p = 0.0308). Both therapies significantly reduced the 24-h mean blood glucose (both, p < 0.001), but neither produced a significant effect on glycaemic variability, calculated as mean amplitude of glycaemic excursions, standard deviation of blood glucose, and mean of daily differences. In addition, the effects on rates of hypoglycaemic episodes were similar between the two therapies. CONCLUSIONS: Chinese patients with type 2 diabetes inadequately controlled with oral antidiabetic agents attained greater benefit from once-daily insulin glargine plus gliclazide modified release regimen than from a twice-daily premixed insulin regimen.

Protective action of liraglutide in beta cells under lipotoxic stress via PI3K/Akt/FoxO1 pathway.

Liraglutide, a modified form of glucagon-like peptide-1 (GLP-1), has been found to improve beta cell function in type 2 diabetes (T2DM). However, the effect of liraglutide on beta cell function under lipotoxic stress and the underlying molecular mechanisms remain unclear. In the present study, we investigated the role of PI3K/Akt/FoxO1 signaling in liraglutide-involved beta cell protection in high free fatty acids (FFAs) condition. The apoptosis, proliferation, and insulin secretion capability of MIN6 cells and islets from C57BL/6J mice were evaluated when exposed to FFAs with/without liraglutide. The expression of effectors involved in PI3K/Akt/FoxO1signalling pathway was detected by real-time PCR and western blotting in MIN6 cells and islets from C57BL/6J mice. Liraglutide substantially inhibited the lipoapoptosis and improved the proliferation and insulin secretion of beta cells in high FFAs condition. Western blot revealed that the phosphorylation of Akt and FoxO1 was markedly decreased under lipid stress but was elevated when treated with liraglutide. Moreover, FFAs could up-regulate the expression levels of p27, Bax, Cidea but down-regulate the expression levels of Pdx-1, MafA, and NeuroD in beta cells, which was canceled by the addition of liraglutide. Moreover, LY294002, a PI3K inhibitor, could significantly abrogate all the protective actions of liraglutide against lipotoxicity. We concluded that liraglutide markedly improved beta cell function under lipid stress and that the protective action of liraglutide was mediated by activation of PI3K/Akt, which resulted in inactivation of FoxO1 along with the down-regulation of p27, Bax, Cidea and up-regulation of Pdx-1, MafA, and NeuroD expressions.

Clinical usefulness of lipid ratios, visceral adiposity indicators, and the triglycerides and glucose index as risk markers of insulin resistance.

BACKGROUND: To directly compare traditional lipid ratios (total cholesterol [TC]/high density lipoprotein cholesterol [HDL-C], non-HDL-C/HDL-C, low density lipoprotein cholesterol [LDL-C]/HDL-C, and triglycerides [TG]/HDL-C), apolipoprotein B (apoB)/apolipoprotein A-I (apoA-I) ratio, visceral adiposity index (VAI), lipid accumulation product (LAP), and the product of TG and fasting glucose (TyG) for strength and independence as risk factors for insulin resistance (IR). METHODS: We conducted a cross-sectional analysis of 7629 Chinese adults using data from the China Health and Nutrition Survey 2009. RESULTS: For all lipid ratios (traditional lipid ratios and apoB/apoA-I), among both sexes, TG/HDL-C explained the most additional percentage of variation in HOMA-IR (2.9% in men, and 2.3% in women); for all variables of interest, the variability in HOMA-IR explained by VAI and TG/HDL-C were comparable; TyG had the most significant association with HOMA-IR, which explained 9.1% for men and 7.8% for women of the variability in HOMA-IR. Logistic regression analysis showed the similar patterns. Receiver operating characteristic (ROC) curve analysis showed that, among both sexes, TG/HDL-C was a better discriminator of IR than apoB/apoA-I; the area under the ROC curve (AUC) for VAI (0.695 in men and 0.682 in women) was greater than that for TG/HDL-C (AUC 0.665 in men and 0.664 in women); TyG presented the greatest value of AUC (0.709 in men and 0.711 in women). CONCLUSION: The apoB/apoA-I performs no better than any of the traditional lipid ratios in correlating with IR. The TG/HDL-C, VAI and TyG are better markers for early identification of IR individuals.

Secular trends in the prevalence of low risk factor burden for cardiovascular disease according to obesity status among Chinese adults, 1993-2009.

BACKGROUND: Cardiovascular disease (CVD) and obesity are now common among Chinese. We aimed to examine secular trends in the prevalence of low risk profile and to examine whether comparable changes in the prevalence of low risk profile across waist circumference (WC) groups and body mass index (BMI) categories have occurred. METHODS: We used data from the nationwide China Health and Nutrition Survey conducted in 1993, 1997, 2000, 2004, 2006, and 2009. There were 7274, 8368, 9369, 8948, 8786, and 9278 participants included in the analyses across the six study periods. We created an index of low risk factor burden from the following variables: not currently smoking, BMI < 25 kg/m2, WC < 90/80 cm in men/women, untreated systolic/diastolic blood pressure < 120/80 mmHg, and not having been previously diagnosed with diabetes. RESULTS: During the period of 1993-2009, the age-adjusted prevalence of low risk profile decreased from 16.2 to 11.5% among men and from 46.3 to 34.6% among women (both P < 0.001); Similar significant trends were observed in all age groups, rural/urban settings, education groups, WC status and BMI categories. The change in the prevalence of low risk profile was more striking among obese persons (P for interaction terms cohort *BMI were < 0.001). In 2009, 2.0 and 25.6% among central obese men and women had a low risk profile; Of note, was that 0.1 and 0.3% general obese men and women had a low risk profile. CONCLUSIONS: The prevalence of low risk profile declined considerably over the past 17 years in all demographic groups, WC status, and BMI categories. Public health prevention strategies are urgently needed.

Wnt3a regulates proliferation, apoptosis and function of pancreatic NIT-1 beta cells via activation of IRS2/PI3K signaling.

Wnt-signaling pathway is implicated in pancreatic development and functional regulation of mature beta-cells. Wnt3a/Wnt pathway activation expands islet cell mass in vitro by increasing proliferation and decreasing apoptosis of beta-cells, thereby enhancing its function. However, the signaling pathways that mediate these effects remain unknown. By using a clonal beta-cell line (NIT-1), we examined the role of IRS2/PI3K in the mediation of Wnt3a-stimulated beta-cell growth. Real-time PCR and Western blot were employed to investigate the activity of Wnt/ß-catenin and IRS2/PI3K signaling. Proliferation of NIT-1 cells was assessed by BrdU incorporation, and apoptosis was quantitatively determined by TUNEL and flow cytometry (FCM). Dkk1, an inhibitor of Wnt signaling, and wortmannin, an inhibitor of PI3K, were also used. Results showed that Wnt3a rapidly activated Wnt/ß-catenin signaling, promoted IRS2 expression and Akt phosphorylation in NIT-1 cells. These effects were completely abrogated by Dkk1 or partially eliminated by wortmannin. Wnt3a also promoted NIT-1 cell proliferation, inhibited cytokine-induced beta-cell apoptosis, and increased insulin secretion. Both of these effects were also eliminated by Dkk1 or wortmannin. Our results demonstrated that Wnt3a regulates proliferation, apoptosis and enhances function of pancreatic NIT-1 beta cells via activation of Wnt/ß-catenin signaling, involving crosstalk with IRS2/PI3K signaling, with the effect of Wnt signaling on beta-cells also being IRS2/PI3K/AKT dependent.

Neutralization of interleukin-17 attenuates high fat diet-induced non-alcoholic fatty liver disease in mice.

Non-alcoholic fatty liver disease (NAFLD) is hepatic manifestation of a metabolic syndrome and includes a spectrum of hepatic steatosis, steatohepatitis, and fibrosis. Interleukin-17 (IL-17) has been reported to play a critical role in inflammatory progression of some liver diseases. The present study was designed to investigate the role of IL-17 on high fat diet-induced NAFLD in C57BL/6 mice. IL-17 blockade with anti-IL-17mAb significantly improved liver function, attenuated hepatic lipid accumulation, suppressed Kuffer cells activation, and decreased pro-inflammatory cytokines levels, which were associated with inhibition of NF-κB signaling cascades activation. Our data suggested that IL-17 was related to disease progression in NAFLD mouse model and blocking IL-17 may be a promising novel therapeutic approach for patients with NAFLD.

Th17 cells in type 1 diabetes.

T1D is an autoimmune disorder, which involves the CD4(+) as well as CD8(+) T-cell-mediated destruction of ß cells. Recently, another population of T cells (Th17) is found to be involved in T1D pathology. This review will discuss the characteristics of Th17 cells and the mechanism of Th17-mediated T1D development. Th17 cell expansion is unstrained under T1D condition. Certain Treg cells are defective in T1D and lose the control of Th17 expansion. In addition, the altered function of APCs and a subset of monocytes which spontaneously secrete IL-1ß and IL-6 in T1D determine the abnormal expansion of Th17 as well. The pathogenic Th17 cells can cause the imbalance between Teff and Treg cells. Conversion from Th17 to Th1 phenotype and Th17 stimulated CTL responses may play an accessory role in T1D as well. Due to the effects of Th17 on T1D, therapeutic strategies designed to inhibit these cells are applicable and the positive effects are obvious. Taken together, Th17 may exert essential effects on the development of T1D. Identification of the underlying mechanism may inspire new viewpoints for the therapy of this disease.

Erythropoietin protects pancreatic ß-cell line NIT-1 cells against cytokine-induced apoptosis via phosphatidylinositol 3-kinase/Akt signaling.

OBJECTIVE: Erythropoietin (EPO) is a cytokine that regulates the proliferation, differentiation, and survival of erythroid progenitor cells. EPO has recently been demonstrated to have a tissue-protective role by mediating anti-apoptotic signals through the erythropoietin receptor (EPOR) in various tissues, including brain, liver, and heart. We have previously examined pancreatic ß-cell line NIT-1 cells for the expression of EPOR by real-time PCR and determined that these cells were protected by EPO against cytokine-induced apoptosis. The precise underlying anti-apoptotic mechanisms in pancreatic ß-cells are poorly understood. The purpose of this study is to examine erythropoietin receptor expression in the NIT-1 pancreatic beta-cell line and the intracellular pathway related with its anti-apoptosis effect in NIT-1 cells. METHODS: we examined the expression of EPOR by western blot. We investigate the role of erythropoietin in the survival of these cells, and whether the PI3K/AKT pathway is involved in this protective process. RESULTS: NIT-1 cells expressed EPOR and, in the presence of certain cytokines, exposure of NIT-1 cells to recombinant human erythropoietin (rhEPO) significantly improved the impaired insulin secretion and inhibited cytokine-induced apoptosis. RhEPO caused a rapid activation of Akt and increased expression of Bcl-2. The protective anti-apoptotic effect of rhEPO was significantly abolished by a specific phosphatidylinositol 3-kiniase (PI3K) inhibitor, LY294002. CONCLUSIONS: Our findings indicate that EPOR is expressed in pancreatic ß-cell line NIT-1 cells and suggest that EPO may act as a survival factor requiring the PI3K/Akt pathway.

Bilateral breast myxedema caused by Graves' disease and responsive to multipoint subcutaneous injection of long-acting glucocorticoid: Case report.

RATIONALE: With the absence of ophthalmopathy, thyroid dermopathy especially lesions at atypical locations is a very rare presentation. We herein report an original case of bilateral breast myxedema caused by Grave's disease. PATIENT CONCERNS: A 21-year-old unmarried woman presented with a 4-month history of Grave's disease and a 1-month history of progressive bilateral breast enlargement. She had symmetrical bilateral breast enlargement with redness and nonpitting thickening of the skin, diffusely enlarged thyroid glands, and no exophthalmos. DIAGNOSIS: Ultrasonography, magnetic resonance imaging scan, and skin biopsy confirmed the diagnosis of bilateral breast myxedema. INTERVENTIONS: The patient was treated with multipoint subcutaneous injections of triamcinolone acetonide in each breast every month. OUTCOMES: The bilateral breast returned approximately to its normal size after therapy for 6 months. CONCLUSIONS: Our case illustrates that multipoint subcutaneous injection of glucocorticoids is beneficial for bilateral breast myxedema.

SREBP-1c, Pdx-1, and GLP-1R involved in palmitate-EPA regulated glucose-stimulated insulin secretion in INS-1 cells.

Impairment of glucose-stimulated insulin secretion (GSIS) caused by glucolipotoxicity is an essential feature in type 2 diabetes mellitus (T2DM). Palmitate and eicosapentaenoate (EPA), because of their lipotoxicity and protection effect, were found to impair or restore the GSIS in beta cells. Furthermore, palmitate was found to up-regulate the expression level of sterol regulatory element-binding protein (SREBP)-1c and down-regulate the levels of pancreatic and duodenal homeobox (Pdx)-1 and glucagon-like peptide (GLP)-1 receptor (GLP-1R) in INS-1 cells. To investigate the underlying mechanism, the lentiviral system was used to knock-down or over-express SREBP-1c and Pdx-1, respectively. It was found that palmitate failed to suppress the expression of Pdx-1 and GLP-1R in SREBP-1c-deficient INS-1 cells. Moreover, down-regulation of Pdx-1 could cause the low expression of GLP-1R with/without palmitate treatment. Additionally, either SREBP-1c down-regulation or Pdx-1 over-expression could partially alleviate palmitate-induced GSIS impairment. These results suggested that sequent SREBP-1c-Pdx-1-GLP-1R signal pathway was involved in the palmitate-caused GSIS impairment in beta cells.

A genetic variation in the fat mass- and obesity-associated gene is associated with obesity and newly diagnosed type 2 diabetes in a Chinese population.

BACKGROUND: Recently, a genome-wide association study identified a strong association between the fat mass- and obesity-associated rs9939609 single nucleotide polymorphism (SNP) and the risk of obesity in European population. However, the results in Chinese population were reported to be contradictory. Therefore, our aim was to examine whether this SNP is associated with obesity and newly diagnosed type 2 diabetes (T2D) in Chinese population. METHODS: We genotyped rs9939609 in 2587 subjects [obesity 243, overweight 976, normal weight 1368 or newly diagnosed T2D 877, impaired glucose regulation 305, normal glucose tolerance (NGT) 1405] using an allelic discrimination assay-by-design TaqMan method on ABI7900HT. We analysed associations of the rs9939609 SNP with obesity and newly diagnosed T2D through Logistic regression analysis. RESULTS: In obesity case-control study, we found that the A allele was strongly associated with obesity and overweight. The odds ratios for the allele A versus T were 1.447 for Obesity versus normal weight (95% CI 1.104-1.896, p = 0.007) and 1.363 for Overweight versus normal weight (95% CI 1.149-1.617, p < 0.0001). In T2D case-control study, the odds ratios for the allele A versus T were 1.305 for T2D versus NGT (95% CI 1.097-1.552, p = 0.003) and 1.280 for combined T2D and impaired glucose regulation (IGR) versus NGT (95% CI 1.089-1.503, p = 0.003). The associations of the A allele with T2D and combined T2D and IGR remained significant with adjustment for age, sex and body mass index (BMI). CONCLUSION: The fat mass- and obesity-associated gene rs9939609 SNP is strongly associated with risk of obesity and newly diagnosed T2D in the Chinese population.

Association between heme oxygenase-1 gene promoter polymorphisms and type 2 diabetes in a Chinese population.

The authors aimed to determine whether 2 functional polymorphisms in the heme oxygenase-1 (HO-1) gene promoter are associated with type 2 diabetes mellitus (T2DM). A Chinese case-control study involving 1,103 newly diagnosed T2DM patients, 371 patients with impaired glucose regulation (IGR), and 1,615 controls was performed (December 2004-December 2007). A (GT)(n) microsatellite polymorphism and a single nucleotide polymorphism, T(-413)A, were genotyped, and their functional relevance was evaluated by examining the level of HO-1 protein expression. For the (GT)(n) microsatellite polymorphism, genotypes with the L (GT)(n) allele (>or=25 GT repeats) were associated with increased odds of IGR or T2DM compared with the S/S genotype (<25 GT repeats) (S/L genotype: odds ratio (OR) = 1.35, P = 0.048; L/L genotype: OR = 1.65, P = 0.006). Subsequent haplotype analysis showed that haplotype TL contributed to increased odds of IGR or T2DM compared with haplotype TS (OR = 1.56, P = 0.003). In functional analyses, HO-1 expression level was significantly reduced in persons with IGR and T2DM carrying the L/L (GT)(n) genotype compared with persons with the S/S genotype. Further haplotype combination assay confirmed the functional dominance of the (GT)(n) microsatellite polymorphism over the T(-413)A single nucleotide polymorphism. These results support an association between the HO-1 (GT)(n) microsatellite polymorphism, HO-1 expression levels, and the odds of T2DM.

Transcription factors involved in glucose-stimulated insulin secretion of pancreatic beta cells.

GSIS, the most important function of pancreatic beta cell, is essential for maintaining the glucose homeostasis. Transcription factors are known to control different biological processes such as differentiation, proliferation and apoptosis. In pancreas, some transcription factors are involved in regulating the function of beta cells. In this review, the role of these transcription factors including Pdx-1, FoxO1, SREBP-1c, and MafA in GSIS is highlighted. The related molecular mechanisms are analyzed as well. Furthermore, the association between the role of transcription factors in GSIS and the development of T2DM is discussed.

Association between C-reactive protein and pre-diabetic status in a Chinese Han clinical population.

BACKGROUND: C-reactive protein (CRP) has been showed to be associated with type 2 diabetes mellitus, but whether CRP underlies glucose disorders in Asian people is still unclear, for they have much lower body mass index (BMI) levels than these Westerns in previous studies. METHOD: In this clinical-based cross-sectional study, the association between CRP and hyperglycaemia in different BMI levels and different gender was compared among 1730 Chinese Han men and women, including 1258 subjects with normal glucose tolerance (NGT), 126 subjects with impaired fasting glucose (IFG) and 346 subjects with impaired glucose tolerance (IGT). Subjects with isolated IFG or IGT were all newly diagnosed and did not use anti-diabetic drugs. RESULTS: Compared with subjects with NGT, BMI, fasting blood glucose, homoeostasis model assessment insulin resistance (HOMA-IR), blood pressure, dyslipidemia, and serum CRP levels were increased in subjects with IGT and IFG. In stratified analyses, increasing CRP levels were strongly associated with prevalence of IGT and IFG in different BMI strata. After adjustment for sex, age, BMI, education, alcohol consumption, smoking, hypertension status, recreational physical activity and occupational physical activity, the ORs across quartiles of CRP were 1.00, 1.43, 2.14 and 2.29 for IFG (P for trend: 0.025) and 1.00, 1.85, 2.32 and 2.79 for IGT (P for trend: 0.012). CONCLUSION: These results support the hypothesis that chronic inflammation may be involved in the development of hyperglycaemia, even though in a thinner and healthy population.

Effects of high concentration glucose on the expression of NF-kappaB, Bax and cytochrome C and apoptosis of islet cells in mice.

The roles of NF-kappaB (NF-kappaB) expression, Bax activity and cytochrome C (Cyt C) release, apoptosis of islet cells induced by high concentration glucose were explored in vitro. Pancreatic islet cells, which were isolated from Kunming mice, were cultured with different concentrations of glucose in DMEM, and divided into the following groups: G1, G2, G3, G4, G5, and G6 groups, corresponding to the glucose concentrations of 5.6, 7.8, 11.1, 16.7, 22.5, and 27.6 mmol/L, respectively. After culture for 120 h, insulin secretion was evaluated by radioimmunoassay, and the NF-kappaB expression was detected by immunocytochemistry. Bax activity and Cyt C release were measured by immunofluorescence, and apoptosis was examined by Hoechst33342 assay. The results showed that in G1, G2 and G3 groups, insulin secretion was enhanced with the increase of glucose concentration, and the NF-kappaB expression was also increased (P<0.05), but Bax activity, Cyt C release and apoptosis rate showed no significant difference among them. However, in G4, G5, and G6 groups, apoptosis rate of islet cells, NF-kappaB expression, Bax activity, and Cyt C release were all significantly increased, and insulin secretion was impaired as compared with G1, G2, and G3 groups (P<0.05). It was concluded that the exposure of islet cells to high glucose could induce islet cells apoptosis as well as impaired insulin secretion. The NF-kappaB signaling pathway and mitochondria pathway in islet cells might play some roles in the progressive loss of islet cells in diabetes. The inhibition of the NF-kappaB expression could be an effective strategy for protecting pancreatic islet cells.

Expression of EPO receptor in pancreatic cells and its effect on cell apoptosis.

In order to explore the expression of erythropoietin receptor (EPOR) in pancreatic cell line NIT-1 and its effect on cell apoptosis after binding with erythropoietin (EPO), NIT-1 cells were cultured and expanded. The expression of EPOR was detected using electrophoresis. NIT-1 apoptosis was induced by cytokines and their effects on cell apoptosis and cell insulin secretion were assayed after binding of EPO to EPOR. The results showed that EPOR was expressed in NIT-1 cells. Recombinant human EPO (rHuEPO) had no effect on cell apoptosis but significantly inhibited apoptosis induced by cytokines. rHuEPO had no effect on cell insulin secretion but significantly improved insulin secretion inhibited by cytokines. From these findings, it was concluded that EPOR was expressed in NIT-1 cells and EPO could protect NIT-1 cells from apoptosis induced by cytokines.

17α­hydroxylase/17,20­lyase deficiency in congenital adrenal hyperplasia: A case report.

Congenital adrenal hyperplasia (CAH) is a rare autosomal recessive disorder caused by mutations in the cytochrome P450 family 17 subfamily A member 1 (CYP17A1) gene located on chromosome 10q24.3, which leads to a deficiency in 17α­hydroxylase/17,20­lyase. The disorder is characterized by low blood levels of estrogens, androgens and cortisol, which leads to a compensatory increase in adrenocorticotropic hormone levels that stimulate the production of mineralocorticoid precursors. This subsequently leads to hypertension, hypokalemia, primary amenorrhea and sexual infantilism. Over 90 distinct genetic lesions have been identified in patients with this disorder. The prevalence of common mutation of CYP17A1 gene differs among ethnic groups. Treatment of this disorder involves replacement of glucocorticoids and sex steroids. Estrogen alone is prescribed for patients who are biologically male with 17α­hydroxylase deficiencies that identify as female. However, genetically female patients may receive estrogen and progesterone supplementation. In the present study, a 17­year­old female with 17α­hydroxylase/17,20­lyase deficiency that presented with primary amenorrhea and sexual infantilism and no hypertension, was examined. The karyotype of the patient was 46, XX, and genetic analysis revealed the presence of a compound heterozygous mutation in exons 6 and 8, leading to the complete absence of 17α­hydroxylase/17,20­lyase activity. The patient was treated with prednisolone and ethinyl estradiol. In addition, a summary of the recent literature regarding CAH is presented.