Cyclic Cushing's syndrome caused by neuroendocrine tumor: a case report

Cushing's syndrome (CS) is a clinical syndrome characterized by hypercortisolemia. Cyclic Cushing's syndrome (CCS), which exhibits a periodic or irregular increasing pattern in cortisol, is a rare type of Cushing's syndrome. A 37-year-old man came to our hospital because of repeated dizzy spells, weakness and hypercortisolemia lasting two weeks. Endocrinological examinations indicated CCS with periodic and intermittent increases in cortisol. Enhanced computed tomography (CT) revealed space occupying lesions on the upper lobe of left lung, and biopsy eventually proved that these were pulmonary carcinoid tumors with ectopic ACTH secretion, which was subsequently manifested a Cushing's syndrome. PET-CT, ultrasound and biopsy of the thyroid gland indicated bilateral thyroid papillary carcinoma. CT scan showed bilateral nodular hyperplasia of the adrenal gland. Enhanced magnetic resonance imaging (MRI) confirmed that the high signal disappeared on the posterior lobe of the pituitary gland and that the pituitary stalk shifted left, which was suspected to be non-functional pituitary microadenoma. The patient underwent surgery involving resection of the left upper pulmonary lobe and the mediastinal lymph node around the hilus pulmonis, which resulted in complete remission of CCS. The patient then chose elective surgery for the thyroid papillary carcinoma. An analysis of the patient's genomic DNA identified a novel mutation in PDE11A: c.2032 (exon 12) G > A, which is associated with primary pigmented nodular adrenocortical disease (PPNAD). This is a novel mutation which has been no previous public clinical report on this mutation as it relates to this disease.

Self-reported snoring is associated with chronic kidney disease independent of metabolic syndrome in middle-aged and elderly Chinese

AIMS/INTRODUCTION

To investigate the correlation between snoring and chronic kidney disease (CKD), and explore whether metabolic syndrome (MetS) plays an important role in this relationship among middle-aged and elderly Chinese.

MATERIALS AND METHODS

The participants included in the present study were categorized into three subgroups based on self-reported snoring frequency (regularly [≥3 times per week], occasionally [between 'regularly' and 'never'] or never [<1 time per month]). An estimated glomerular filtration rate <60 mL/min/1.73 m2 was considered as CKD. We diagnosed MetS based on the 2004 Chinese Diabetes Society criteria. We explored the relationship between snoring and CKD by using multiple logistic regressions.

RESULTS

The frequency of MetS, MetS components and CKD was dramatically higher in regular snorers than in non-snorers and occasional snorers. The odds ratios for MetS and all the MetS elements, except for hyperglycemia, increased progressively with the snoring frequency (P < 0.001). Upon additional adjustment for other MetS components, snoring was not significantly related with hypertension; however, the associations between snoring frequency and overweight/obesity and dyslipidemia became attenuated, but still remained statistically significant (P < 0.01). Interestingly, odds ratios for CKD also increasingly augmented with snoring frequency (P < 0.001). Upon further adjustment for individual MetS components or MetS, regular snoring also resulted in a significantly increased odds ratio for CKD (odds ratio 1.72; P = 0.034) relative to non-snoring.

CONCLUSIONS

Self-reported snoring is closely associated with CKD independent of MetS among middle-aged and elderly Chinese.

Insulin regulates glucagon-like peptide-1 secretion by pancreatic alpha cells

PURPOSE

Proglucagon is expressed in both pancreatic alpha cells and intestinal epithelial L cells and is cleaved into glucagon and glucagon-like peptide-1 (GLP-1) by different prohormone convertases (PCs). Recent studies have shown that α-cells can also secrete GLP-1, which may improve islet function. However, little is known about the factors influencing GLP-1 secretion by α cells. In this study, we investigated whether insulin promotes GLP-1 secretion by α cells, as well as the mechanisms underlying this phenomenon.

METHODS

We cultured the alpha-cell line In-R1-G9 in low- or high-glucose medium in the presence or absence of insulin to determine the influence of glucose concentrations on the actions of insulin. We also treated In-R1-G9 cells with insulin for different times and at different doses. Then GLP-1 and glucagon protein expression levels were estimated. Moreover, ERK and phosphatidylinositol-3-kinase/AKT (PI3K/AKT) pathway activity levels and prohormone convertase expression levels were evaluated to elucidate the mechanism underlying the effects of insulin on GLP-1 secretion by α-cells.

RESULTS

Insulin promoted GLP-1 secretion in a time- and dose-dependent manner under high-glucose conditions. Inhibiting the PI3K/AKT pathway with LY294002 and the Ras/mitogen-activated protein kinase (RAS/MAPK) pathway with PD98059 reduced GLP-1 secretion, respectively, in inhibitor-treated cells compared with insulin-treated cells. Moreover, insulin increased prohormone convertase 1/3 expression levels in the corresponding group of IN-R1-G9 cells compared with the control group of cells.

CONCLUSION

Insulin facilitates GLP-1 secretion by pancreatic alpha cells by inducing PC1/3 expression under high-glucose conditions, a phenomenon that may be associated mainly with PI3K/AKT pathway activation.

Activation of the STING-IRF3 pathway promotes hepatocyte inflammation, apoptosis and induces metabolic disorders in nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a common result of obesity and metabolic syndrome. Hepatocyte injury and metabolic disorders are hallmarks of NAFLD. Stimulator of interferon genes (STING) and its downstream factor interferon regulatory factor 3 (IRF3) trigger inflammatory reaction in response to the presence of cytosolic DNA. STING has recently been shown to play an important role in early alcoholic liver disease. However, little is known about the role of STING-IRF3 pathway in hepatocyte injury. Here, we aimed to examine the effect of STING-IRF3 pathway on hepatocyte metabolism, inflammation and apoptosis.

METHODS

We examined the activation of the STING-IRF3 pathway, a high-fat diet (HFD)-induced obese mouse model, and determined the role of this pathway in a free fatty acid (FFA)-induced hepatocyte inflammatory response, injury, and dysfunction in L-O2 human liver cells.

RESULTS

STING and IRF3 were upregulated in livers of HFD-fed mice and in FFA-induced L-O2 cells. Knocking down either STING or IRF3 led to a significant reduction in FFA-induced hepatic inflammation and apoptosis, as evidenced by modulation of the nuclear factor κB (NF-κB) signaling pathway, inflammatory cytokines, and apoptotic signaling. Additionally, STING/IRF3 knockdown enhanced glycogen storage and alleviated lipid accumulation, which were found to be associated with increased expression of hepatic enzymes in glycolysis and lipid catabolism, and attenuated expression of hepatic enzymes in gluconeogenesis and lipid synthesis.

CONCLUSIONS

Our results suggest that the STING-IRF3 pathway promotes hepatocyte injury and dysfunction by inducing inflammation and apoptosis and by disturbing glucose and lipid metabolism. This pathway may be a novel therapeutic target for preventing NAFLD development and progression.

PINK1-Parkin alleviates metabolic stress induced by obesity in adipose tissue and in 3T3-L1 preadipocytes

Mitochondria play an important role in cellular metabolism and are closely related with metabolic stress. Recently, several studies have shown that mitophagy mediated by PTEN-induced putative kinase 1 (PINK1) and Parkin may play a critical role in clearing the damaged mitochondria and maintaining the overall balance of intracellular mitochondria in quality and quantity. A previous study showed that PINK1 and Parkin were overexpressed in adipose tissue in obese subjects. However, it is still unclear whether a direct relationship exists between obesity and mitophagy. In this study, we created a high-fat-diet (HFD)-induced obese mouse model and examined the expression of PINK1 and Parkin in adipose tissue using western blot and real-time quantitative PCR. After we confirmed that there is an interesting difference between regular-chow-fed mice and HFD-induced obese mice in the expression of PINK1 and Parkin in vivo, we further tested the expression of PINK1 and Parkin in 3T3-L1 preadipocytes in vitro by treating cells with palmitic acid (PA) to induce metabolic stress. To better understand the role of PINK1 and Parkin in metabolic stress, 3T3-L1 preadipocytes were transfected with small interfering RNA (siRNA) of PINK1 and Parkin followed by PA treatment. Our results showed that under lower concentrations of PA, PINK1 and Parkin can be activated and play a protective role in resisting the harmful effects of PA, including protecting the mitochondrial function and resisting cellular death, while under higher concentrations of PA, the expression of PINK1 and Parkin can be inhibited. These results suggest that PINK1-Parkin can protect mitochondrial function against metabolic stress induced by obesity or PA to a certain degree.

HbA1c Cutoff Point of 5.9% Better Identifies High Risk of Progression to Diabetes among Chinese Adults: Results from a Retrospective Cohort Study

AIMS

This article performed a retrospective cohort study to estimate the annual incidence rates of diabetes and to assess the utility of HbA1c as a predictor for progression to diabetes in Chinese community adults aged 40 years or older.

METHODS

In all, 2778 nondiabetic subjects (including 1901 women) underwent HbA1c testing and oral glucose tolerance test (OGTT) measurements at baseline and after 3 years. Diabetes and prediabetes were defined using the WHO criteria. The HbA1c cutoff points were evaluated to predict the future risks of diabetes. Relative risk (RR) was calculated using the chi-square test. The area under the receiver operating characteristic (ROC) curve (AUC) was used to evaluate the predictive efficiency of fasting plasma glucose (FPG), 2 hr postprandial plasma glucose (2hPG), and HbA1c for progression to diabetes. A superior cutoff point was defined as the point on the ROC curve with a larger Youden index.

RESULTS

Overall, 7.5% (210/2778) of the subjects progressed to diabetes, yielding an annual 2.5% diabetes incidence rate. Additionally, 4.5% (100/2227) of the subjects with normal glucose tolerance (NGT) and 19.6% (110/561) of the subjects with prediabetes progressed to diabetes, and the relative risk of progression to diabetes was 5.188 times higher in subjects with prediabetes than in subjects with NGT (p < 0.001). Compared to subjects with HbA1c values ≤ 5.6%, the RRs of progression to diabetes in subjects whose HbA1c ranged from 5.7 to 5.8%, 5.9 to 6.2%, 6.3 to 6.4%, and ≥6.5% were 1.165, 2.582, 5.732, and 16.619, respectively. However, the RRs for subjects with HbA1c ranging from 5.7 to 5.8% and those with HbA1c ≤ 5.6% did not differ significantly (p = 0.615). The AUCs for predicting diabetes after 3 years by FPG, 2hPG, and HbA1c were 0.752 (95% confidence interval 0.718-0.787), 0.710 (95% confidence interval 0.671-0.748), and 0.756 (95% confidence interval 0.720-0.793), respectively. The HbA1c cutoff point of 5.9% (sensitivity of 0.771 and specificity of 0.580) may better identify individuals at high risk of progression to diabetes than the 5.7% value (sensitivity of 0.862 and specificity of 0.371) due to the former's larger Youden index of 0.351, which exceeded the indices for FPG and 2hPG.

CONCLUSIONS

The use of HbA1c values ≥ 5.9% may provide greater accuracy in evaluating the risk of progression to diabetes and identify individuals with prediabetes with greater reliability among Chinese adults.

Mesenchymal stromal cells ameliorate oxidative stress-induced islet endothelium apoptosis and functional impairment via Wnt4-β-catenin signaling

Background

Islet dysfunction and destruction are the common cause for both type 1 and type 2 diabetes mellitus (T2DM). The islets of Langerhans are highly vascularized miniorgans, and preserving the structural integrity and full function of the microvascular endothelium is vital for protecting the islets from the infiltration of immune cells and secondary inflammatory attack. Mesenchymal stromal cell (MSC)-based therapies have been proven to promote angiogenesis of the islets; however, the underlying mechanism for the protective role of MSCs in the islet endothelium is still vague.

Methods

In this study, we used MS-1, a murine islet microvascular endothelium cell line, and an MSC-MS1 transwell culturing system to investigate the protective mechanism of rat bone marrow-derived MSCs under oxidative stress in vitro. Cell apoptosis was detected by TUNEL staining, annexin V/PI flow cytometry analysis, and cleaved caspase 3 western blotting analysis. Endothelial cell activation was determined by expression of intercellular cell adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM), as well as eNOS phosphorylation/activation. The changes of VCAM-1, eNOS, and the β-catenin expression were also tested in the isolated islets of T2DM rats infused with MSCs.

Results

We observed that treating MS-1 cells with H₂O₂ triggered significant apoptosis, induction of VCAM expression, and reduction of eNOS phosphorylation. Importantly, coculturing MS-1 cells with MSCs prevented oxidative stress-induced apoptosis, eNOS inhibition, and VCAM elevation in MS-1 cells. Similar changes in VCAM-1 and eNOS phosphorylation could also be observed in the islets isolated from T2DM rats infused with MSCs. Moreover, MSCs cocultured with MS-1 in vitro or their administration in vivo could both result in an increase of β-catenin, which suggested activation of the β-catenin-dependent Wnt signaling pathway. In MS-1 cells, activation of the β-catenin-dependent Wnt signaling pathway partially mediated the protective effects of MSCs against H₂O₂-induced apoptosis and eNOS inhibition. Furthermore, MSCs produced a significant amount of Wnt4 and Wnt5a. Although both Wnt4 and Wnt5a participated in the interaction between MSCs and MS-1 cells, Wnt4 exhibited a protective role while Wnt5a seemed to show a destructive role in MS-1 cells.

Conclusions

Our observations provide evidence that the orchestration of the MSC-secreted Wnts could promote the survival and improve the endothelial function of the injured islet endothelium via activating the β-catenin-dependent Wnt signaling in target endothelial cells. This finding might inspire further in-vivo studies.

Electrochemical Skin Conductance May Be Used to Screen for Diabetic Cardiac Autonomic Neuropathy in a Chinese Population with Diabetes

Aims. This study aimed to assess whether the electrochemical skin conductance (ESC) could be used to screen for diabetic cardiac autonomic neuropathy (DCAN) in a Chinese population with diabetes. Methods. We recruited 75 patients with type 2 diabetes mellitus (T2DM) and 45 controls without diabetes. DCAN was diagnosed by the cardiovascular autonomic reflex tests (CARTs) as gold standard. In all subjects ESCs of hands and feet were also detected by SUDOSCAN™ as a new screening method. The efficacy was assessed by receiver operating characteristic (ROC) curve analysis. Results. The ESCs of both hands and feet were significantly lower in T2DM patients with DCAN than those without DCAN (67.33 ± 15.37 versus 78.03 ± 13.73, P = 0.002, and 57.77 ± 20.99 versus 75.03 ± 11.41, P < 0.001). The ROC curve analysis showed the areas under the ROC curve were both 0.75 for ESCs of hands and feet in screening DCAN. And the optimal cut-off values of ESCs, sensitivities, and specificities were 76 μS, 76.7%, and 75.6% for hands and 75 μS, 80.0%, and 60.0% for feet, respectively. Conclusions. ESC measurement is a reliable and feasible method to screen DCAN in the Chinese population with diabetes before further diagnosis with CARTs.

Ectopic Cushing's syndrome due to retroperitoneal ACTH-producing paragangliomas

Extra-adrenal pheochromocytomas, or paragangliomas, are rare tumours that derive from extra-adrenal chromaffin cells. Cushing's syndrome (CS) caused by paragangliomas is extremely rare. We report a 53-year-old man with hypertension, diabetes, and symptoms of hypokalemia. Computer tomography (CT) revealed two retroperitoneal masses and bilateral adrenal hyperplasia. Together with the laboratory examinations, ectopic CS caused by multiple paragangliomas was highly suspected. The patient underwent resections of retroperitoneal tumours, left kidney, and left adrenal; postoperative histopathology confirmed two paragangliomas that were both positively stained for adrenocorticotropic hormone (ACTH). He got clinical and biochemical recoveries without any recurrent evidence at the nine-month followup.

Irisin modulates the association of interleukin-17A with the presence of non-proliferative diabetic retinopathy in patients with type 2 diabetes

The role of inflammation in pathogenesis of diabetic retinopathy (DR) is getting increasingly recognized. However, it is unclear whether and how non-proliferative diabetic retinopathy (NPDR) is affected by Interleukin-17A (IL-17A) and Interleukin-22 (IL-22), two well-known inflammatory factors, and irisin, a novel potential anti-inflammatory factor. Here we recruited 40 type 2 diabetes mellitus (T2DM) patients with NPDR, 60 T2DM patients without DR (no-DR), and 20 normal glucose tolerance (NGT) controls. Serum levels of IL-17A, IL-22, and irisin were examined. Compared with NGT and no-DR subjects, NPDR group had significantly higher IL-17A levels. Irisin levels were significantly lower in T2DM patients, while IL-22 levels were not significantly different across all three groups. Multiple logistic regression analysis revealed that IL-17A significantly increased the risk of NPDR (OR = 1.22, P < 0.05) before adjusting for irisin. When irisin was included in the model, neither irisin nor IL-17A was associated with NPDR. Further partial correlation analysis showed that irisin was intrinsically correlated with IL-17A even after multiple adjustment (r = -0.252; P = 0.018). These findings suggest that IL-17A is an independent risk factor of NPDR, and irisin could protect against DR through potential anti-IL-17A effects.

Relationship of Hemoglobin A1c with β Cell Function and Insulin Resistance in Newly Diagnosed and Drug Naive Type 2 Diabetes Patients

OBJECTIVE

To investigate changes in the glycated hemoglobin A1c (A1c) level and those in β cell function and insulin resistance in newly diagnosed and drug naive type 2 diabetes patients and to evaluate the relationship between them.

DESIGN AND METHODS

A total of 818 newly diagnosed diabetic individuals who were ≥ 40 years of age were recruited. The subjects were grouped by A1c values (<6.5%, 6.5-7%, 7-8%, 8-9%, and ≥ 9%). The homeostasis model assessment (HOMA) was used to evaluate pancreatic β cell function (HOMA-β) and insulin resistance (HOMA-IR). ANOVA, t-tests, and binary logistic regression analysis were used for data analysis.

RESULTS

Compared with subjects with A1c values <6.5%, individuals with an A1c of 6.5-7% exhibited an increased HOMA-β index. However, the HOMA-β index was significantly decreased at A1c values ≥ 7% and further decreased by 9.3% and by 23.7%, respectively, at A1c values of 7-8% and 8-9%. As A1c increased to ≥ 9%, a 62% reduction in β cell function was observed, independently of age, gender, body mass index (BMI), blood pressure (BP), blood lipids, and hepatic enzyme levels. Meanwhile, insulin resistance was significantly increased with an increase in A1c values.

CONCLUSIONS

Elevated A1c values (≥ 7%) were associated with substantial reductions in β cell function.

Circulating Levels of Betatrophin and Irisin Are Not Associated with Pancreatic β-Cell Function in Previously Diagnosed Type 2 Diabetes Mellitus Patients

Betatrophin and irisin are two recently identified hormones which may participate in regulating pancreatic β-cell function. However, the associations of these two hormones with β-cell function remain unclear. The present study aims to demonstrate the associations of circulating betatrophin and irisin levels with β-cell function, assessed by the area under the curve (AUC) of C-peptide, and the possible correlation between these two hormones in previously diagnosed type 2 diabetes mellitus (T2DM) patients. In total, 20 age-, sex-, and body mass index- (BMI-) matched normal glucose tolerance (NGT) subjects and 120 previously diagnosed T2DM patients were included in this study. Partial correlation analysis was used to evaluate the relationships between these two hormones and indexes of β-cell function and insulin resistance. Our results showed that betatrophin levels were significantly elevated, while irisin levels were significantly decreased, in patients with T2DM compared with NGT subjects. However, partial correlation analysis showed that betatrophin levels did not correlate with β-cell function-related variables or insulin resistance-related variables before or after controlling multiple covariates, while irisin correlated positively with insulin sensitivity but is not associated with β-cell function-related variables. Besides, no correlation was observed between betatrophin and irisin levels. Hence we concluded that betatrophin and irisin were not associated with β-cell function in previously diagnosed T2DM patients.

Genetic diversity analysis of tree peony germplasm using iPBS markers

We examined the genetic diversity of 10 wild species (populations) and 55 varieties of tree peony using inter-primer binding site (iPBS) markers. From a total of 36 iPBS primers, 16 were selected based on polymorphic amplification. The number of bands amplified by each primer ranged from 9 to 19, with an average of 12.88 bands per primer. The length of bands ranged from 100 to 2000 bp, concentrated at 200 to 1800 bp. Sixteen primers amplified 206 bands in total, of which 173 bands were polymorphic with a polymorphism ratio of 83.98%. Each primer amplified 10.81 polymorphic bands on average. The data were then used to construct a phylogenetic tree using unweighted pair group method with arithmetic mean methods. Clustering analysis showed that the genetic relationships among the varieties were not only related to the genetic background or geographic origin, but also to the flowering phase, flower color, and flower type. Our data also indicated that iPBS markers were useful tools for classifying tree peony germplasms and for tree peony breeding, and the specific bands were helpful for molecular identification of tree peony varieties.

Subclinical hypothyroidism might worsen the effects of aging on serum lipid profiles: a population-based case-control study

BACKGROUND

Dyslipidemia is an important global health problem, particularly in the elderly population. Traditionally, the high prevalence of dyslipidemia in elderly people is considered a "natural condition." Notably, subclinical hypothyroidism (SCH) is one of the most important risk factors for dyslipidemia. Few studies have assessed whether SCH plays a role in the increase in age-related dyslipidemia. This study aimed to explore the association between SCH and lipid profiles in different age groups.

METHODS

This was a large-scale, population-based, case-control study. The population was derived from the REACTION study conducted across China. A total of 17,046 individuals (8827 cases and 8219 controls) aged 40 years or older were enrolled in the final analyses. The relationships between SCH and serum lipid parameters in each age group were evaluated after adjustment for thyroid hormones and common confounding factors.

RESULTS

In the entire population, thyrotropin (TSH), the key indicator of SCH, was positively associated with cholesterol parameters (total cholesterol [TC] and low-density lipoprotein cholesterol [LDL-C]) through the sixth decade of life. After adjusting for common confounding factors and thyroid hormones, each 1 mIU/L increase in TSH was estimated to elevate the TC level by 0.0147 mmol/L and 0.0551 mmol/L, respectively, in individuals aged 40-49 years and 60-69 years. Similarly, with each 1 mIU/L increase in TSH, the LDL-C level tended to show gradually greater increases as age increased. In moderately old subjects (60-69 years), mild (TSH≤10 mIU/L) and significant (TSH>10 mIU/L) SCH increased the concentration of TC approximately 1.03- and 1.36-fold, and the concentration of LDL-C approximately 1.19- and 1.65-fold, respectively, when compared with younger subjects.

CONCLUSIONS

TSH exhibited a stronger effect on the TC and LDL-C level in moderately old subjects than in younger subjects. SCH might augment and worsen the effects of aging on serum lipid profiles.

Irisin has no effect on lipolysis in 3T3-L1 adipocytes or fatty acid metabolism in HepG2 hepatocytes

Irisin, a newly identified myokine responsible for browning of white or beige adipocytes, has been reported to be present at reduced levels in diabetic patients and associated with obesity, serum triglyceride (TG) levels, and intrahepatic TG levels. We wondered whether irisin could directly affect fatty acid and TG metabolism in adipocytes and hepatocytes. We examined the effects of various concentrations of irisin on lipolysis (according to Oil Red O staining, free fatty acid release, and glycerol release), protein expression of HSL and ATGL, and mRNA expression of other lipid-related genes (UCP-1, PPARγ, FABP-4, HSL, ATGL, PPARα, and CPT-1) in mature 3T3-L1 adipocytes, as well as mRNA levels of genes involved in the synthesis (SREBP-1C and FAS) and β-oxidation (PPARα and CPT-1) of fatty acids in HepG2 hepatocytes under physiological or hyperglycemic conditions. Our results revealed that although irisin significantly increased the mRNA levels of UCP-1 and PPARα, it failed to show detectable effects on lipolysis, HSL or ATGL protein levels, or the mRNA expression of other lipid-related genes in mature 3T3-L1 adipocytes. In HepG2 hepatocytes, high glucose induced the upregulation of SREBP-1C and FAS and the downregulation of PPARα; however, no significant effect of irisin on gene expression was observed under either physiological or hyperglycemic conditions. We therefore conclude that irisin has no significant direct effect on lipolysis in 3T3-L1 adipocytes or on fatty acid metabolism in HepG2 hepatocytes.

Diagnostic efficiency of hemoglobin A1c for newly diagnosed diabetes and prediabetes in community-based Chinese adults aged 40 years or older

BACKGROUND

Europeans and Americans are gradually accepting the hemoglobin A1c (HbA1c) threshold of 6.5% for diagnosing diabetes proposed by the American Diabetes Association, but the cutoff of HbA1c for the Chinese population is unclear. We evaluated the diagnostic efficiency of HbA1c for diagnosing newly diagnosed diabetes and prediabetes in community-based Chinese adults 40 years of age or older.

SUBJECTS AND METHODS

In this study 8,239 subjects (5,496 women) 40-90 years of age underwent HbA1c and oral glucose tolerance test measurement after an overnight fast. Diabetes and prediabetes were defined by the World Health Organization criteria. The area under the receiver operating characteristic curve (AUC) was used to evaluate the diagnostic efficiency of HbA1c, and the optimal cutoff was defined as the point on the receiver operating characteristic curve with the largest Youden index. Spearman correlation was used for correlation analysis.

RESULTS

The prevalence of newly diagnosed diabetes and prediabetes was 10.7% (880/8,239) and 19.0% (1,564/8,239), respectively. Fasting plasma glucose and postprandial plasma glucose were positively correlated with HbA1c level (r=0.725 and r=0.673, both P<0.001, respectively). For diagnosing diabetes, the AUC was 0.857 (95% confidence interval, 0.841-0.873), and the optimal cutoff for HbA1c was 6.3%, with the largest Youden index being 0.581. For diagnosing prediabetes, the AUC was 0.681 (95% confidence interval, 0.666-0.697), and the optimal cutoff for HbA1c was 5.9%, with the largest Youden index being 0.280.

CONCLUSIONS

An HbA1c threshold of 6.3% was highly valuable for diagnosing newly diagnosed diabetes, and a value of 5.9% was weakly valuable for diagnosing prediabetes in community-based Chinese adults 40 years of age or older.

Triglyceride levels are closely associated with mild declines in estimated glomerular filtration rates in middle-aged and elderly Chinese with normal serum lipid levels

OBJECTIVE

To investigate the relationship between lipid profiles [including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C)] and a mild decline in the estimated glomerular filtration rate (eGFR) in subjects with normal serum lipid levels.

DESIGN AND METHODS

In this study, we included 2647 participants who were ≥ 40 years old and had normal serum lipid levels. The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was used to estimate the GFR. A mildly reduced eGFR was defined as 60-90 mL/min/1.73 m(2). First, multiple linear regression analysis was used to estimate the association of lipid profiles with the eGFR. Then, the levels of each lipid component were divided into four groups, using the 25th, 50th and 75th percentiles as cut-off points. Finally, multiple logistic regression analysis was used to investigate the association of different lipid components with the risk of mildly reduced eGFR.

RESULTS

In the group with a mildly reduced eGFR, TG and LDL-C levels were significantly increased, but HDL-C levels were significantly decreased. After adjusting for age, gender, body mass index (BMI), systolic blood pressure (SBP), glycated hemoglobin (HbA1c), smoking and drinking, only TC and TG were independently related to the eGFR. Additionally, only TG showed a linear relationship with an increased risk of a mildly reduced eGFR, with the highest quartile group (TG: 108-150 mg/dl [1.22-1.70 mmol/L]) having a significantly increased risk after adjusting for the above factors.

CONCLUSIONS

Triglyceride levels are closely associated with a mildly reduced eGFR in subjects with normal serum lipid levels. Dyslipidemia with lower TG levels could be used as new diagnostic criteria for subjects with mildly reduced renal function.

Metabolic abnormalities, but not obesity, contribute to the mildly reduced eGFR in middle-aged and elderly Chinese

BACKGROUND

The role of obesity as a determinant of kidney dysfunction has not reached an agreement and the underlying reason may be due to the heterogeneity of obese phenotypes. The aim of the study was to explore the associations of different obese phenotypes with the change of estimated glomerular filtration rate (eGFR) and the roles of obesity and metabolic abnormalities in this association.

METHODS

eGFR was calculated in 8,586 participants (≥ 40 years old). eGFR 60-90 mL/min/1.73 m(2) was defined as the mildly reduced eGFR. Multiple logistic regression analysis was used to determine odds ratios (ORs) for mildly reduced eGFR in the metabolically healthy obese (MHO), metabolically abnormal non-obese (MANO) and metabolically abnormal obese (MAO) groups, using the metabolically healthy non-obese (MHNO) subjects as the reference group. Meanwhile, the associations of body mass index (BMI), waist circumference (WC) and metabolic abnormalities (including hypertension, hyperglycemia and dyslipidemia) with the risk of mildly reduced eGFR were also investigated.

RESULTS

The proportion of MHNO, MHO, MANO and MAO subjects was 8.3, 17.1, 10.1 and 64.5 %, respectively. Increased ORs were observed in MANO (OR 1.51, P = 0.014) and MAO (OR 1.47, P = 0.015) groups, after adjusting for age, gender, smoking, drinking, BMI and WC. When further adjusting for metabolic abnormalities, MANO (OR 1.24, P = 0.247) and MAO (OR 1.17, P = 0.366) subjects would not present increased risk of mildly reduced eGFR any more. Oppositely, fasting insulin (OR 1.03, P < 0.001), hyperglycemia (OR 1.25, P = 0.002) and dyslipidemia (OR 1.25, P = 0.002), but not hypertension, BMI and WC, significantly increased the risk of mildly reduced eGFR.

CONCLUSIONS

Metabolic abnormalities, but not simple obesity, may contribute to the mildly reduced eGFR in middle-aged and elderly Chinese.

Fluctuation between fasting and 2-H postload glucose state is associated with chronic kidney disease in previously diagnosed type 2 diabetes patients with HbA1c ≥ 7%

Objective

To investigate how the glucose variability between fasting and a 2-h postload glucose state (2-h postload plasma glucose [2hPG]-fasting plasma glucose [FPG]) is associated with chronic kidney disease (CKD) in middle-aged and elderly Chinese patients previously diagnosed with type 2 diabetes.

Design and Methods

This cross-sectional study included 1054 previously diagnosed type 2 diabetes patients who were 40 years of age and older. First, the subjects were divided into two groups based on a glycated hemoglobin (HbA1c) value of 7%. Each group was divided into two subgroups, with or without CKD. The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation was used to estimate the glomerular filtration rate (GFR). CKD was defined as eGFR<60 mL/min/1.73 m². Multiple linear regression analysis was used to estimate the association between the 2hPG-FPG and eGFR. The 2hPG-FPG value was divided into four groups increasing in increments of 36 mg/dl (2.0 mmol/L): 0–72, 72–108, 108–144 and ≥144 mg/dl, based on the quartiles of patients with HbA1c levels ≥7%; then, binary logistic regression analysis was used to investigate the association between 2hPG-FPG and the risk of CKD.

Results

In the patients with HbA1c levels ≥7%, the 2hPG-FPG was significantly associated with decreased eGFR and an increased risk of CKD independent of age, gender, body mass index (BMI), systolic blood pressure (BP), diastolic BP, smoking, and drinking, as well as fasting insulin, cholesterol, triglyceride, and HbA1c levels. The patients with 2hPG-FPG values ≥144 mg/dl showed an increased odds ratio (OR) of 2.640 (P = 0.033). Additionally, HbA1c was associated with an increased risk of CKD in patients with HbA1c values ≥7%.

Conclusions

The short-term glucose variability expressed by 2hPG-FPG is closely associated with decreased eGFR and an increased risk of CKD in patients with poor glycemic control (HbA1c≥7%).

Matrix metalloproteinase levels in chronic thoracic aortic dissection

BACKGROUND

Imbalance between matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) can lead to aortic wall failure. We hypothesized that patients with aneurysms resulting from chronic descending thoracic aortic dissection have elevated tissue and plasma levels of specific MMPs and decreased tissue levels of TIMPs.

MATERIALS AND METHODS

Aortic tissue was obtained from 25 patients who required surgical repair of descending thoracic aortic aneurysm due to chronic aortic dissection and from 17 organ-donor controls without aortic disease. Tissue levels of MMP-1, -2, -3, -9, -12, and -13 and TIMP-1 and -2 were measured by colorimetric activity assay or enzyme-linked immunosorbent assay and confirmed by Western blot and immunohistochemistry. Blood obtained from the 25 patients and 15 controls without aortic diseases was used to compare plasma levels of MMP-3, -9, and -12.

RESULTS

Total MMP-1, total MMP-9, and active MMP-9 levels were higher and total MMP-2 levels were lower in dissection tissue than in control tissue. Additionally, the MMP-9 to TIMP-1 and active to total MMP-2 ratios were higher and the MMP-2 to TIMP-2 ratio was lower in dissection tissue. Furthermore, patients had higher plasma active to total MMP-9 ratios than the controls. Age and hypertension were associated with increased MMP levels.

CONCLUSIONS

Increased levels of several MMPs and increased MMP to TIMP ratios in aortic tissue from patients suggest an environment that favors proteolysis, which may promote progressive extracellular matrix destruction and medial degeneration after aortic dissection. An elevated active to total MMP-9 ratio in plasma may be a biomarker for end-stage aneurysm development in patients with chronic thoracic aortic disease.

Bone marrow mesenchymal stem cells ameliorate inflammatory factor-induced dysfunction of INS-1 cells on chip

Using a microfluidic chip, we have investigated whether bone marrow mesenchymal stem cells (BM-MSCs) could ameliorate IL-1β/IFN-γ-induced dysfunction of INS-1 cells. BM-MSCs were obtained from diabetes mellitus patients and their cell surface antigen expression profiles were analyzed by flow cytometric. INS-1 cells were cocultured with BM-MSCs on a microfluidic chip with persistent perfusion of medium containing 1 ng/mL IL-1β and 2.5 U/mL IFN-γ for 72 h. BM-MSCs could partially rescue INS-1 cells from cytokine-induced dysfunction and ameliorate the expression of insulin and PDX-1 gene in INS-1 cells. Thus BM-MSCs can be viewed as a promising stem cell source to depress inflammatory factor-induced dysfunction of pancreatic β cells in diabetic patients.

Elevated peripheral frequencies of Th22 cells: a novel potent participant in obesity and type 2 diabetes

OBJECTIVE

Chronic low-grade inflammation has long been recognized as the central link between obesity and type 2 diabetes (T2D). The novel subset of T helper (Th) cells, Th22, plays an emerging role in chronic inflammation. We investigated the potential association between Th22 and the pathogenesis of obesity and T2D.

METHODS

Ninety T2D inpatients (T2D group), 30 healthy participants with BMI ranged from 19 to 23.9 kg/m2 (CTL group) and 30 metabolically healthy obese controls with BMI ≥ 30 kg/m2 (MHO group) were employed in our study. Peripheral frequencies of Th22 and Th1 and Th17 cells were determined by flow cytometry based on their specific cytokine patterns. Cytokine levels in fresh plasma were quantified by ELISA.

RESULTS

Compared to that in CTL group (1.18±0.06%, n = 28), peripheral frequency of Th22 cells was significantly increased in MHO group (1.88±0.10%, n = 30) and in T2D group (2.247±0.10%, n = 89). There was a consistent notable increase in plasma interleukin (IL)-22 of T2D patients [47.56 (30.55-76.89) pg/mL] as compared with that of MHO group [36.65 (29.52-55.70) pg/ml; *P<0.0001] and CTLs [36.33 (31.93-40.62) pg/mL; *P<0.0001]. Furthermore, other than Th1/Th17, previously frequently described participants in obesity and T2D, there was a strong correlation between Th22 frequency and the homeostasis model of assessment for insulin resistance index (r = 0.6771, *P<0.0001) and HOMA for β-cell function (r = -0.7264, *P<0.0001).

CONCLUSIONS

There were increased Th22 frequencies and IL-22 levels in obesity and T2D. Elevated Th22 and IL-22 also aided in the differentiation of MHO from T2D patients. The notable correlation implied that Th22 might play a more determinant role in both insulin resistance and β-cell impairment.

Triglycerides and ratio of triglycerides to high-density lipoprotein cholesterol are better than liver enzymes to identify insulin resistance in urban middle-aged and older non-obese Chinese without diabetes

BACKGROUND

Insulin resistance (IR) plays an important pathophysiological role in the development of diabetes, dyslipidemia, hypertension, and cardiovascular disease. Moreover, IR can occur even in non-obese people without diabetes. However, direct detection of IR is complicated. In order to find a simple surrogate marker of IR early in non-obese people, we investigate the association of commonly-used biochemical markers (liver enzymes and lipid profiles) with IR in urban middle-aged and older non-obese Chinese without diabetes.

METHODS

This cross-sectional study included 1 987 subjects (1 473 women). Fasting blood samples were collected for measurement of glucose, insulin, liver enzymes, lipid profiles and creatinine. Subjects whose homeostasis model of assessment-IR (HOMA-IR) index values exceeded the 75th percentile (2.67 for women and 2.48 for men) of the population were considered to have IR. The area under the receiver operating characteristic curve (ROC) was used to compare the power of potential markers in identifying IR.

RESULTS

Triglycerides (TG) and ratio of TG to high-density lipoprotein cholesterol (TG/HDL-C) discriminated IR better than other indexes for both sexes; areas under the receiver operating characteristic (ROC) curves (AUC) values were 0.770 (95% confidence interval 0.733-0.807) and 0.772 (0.736-0.809), respectively, for women and 0.754 (0.664-0.844) and 0.756 (0.672-0.840), respectively, for men. To identify IR, the optimal cut-offs for TG and TG/HDL-C ratio were 1.315 mmol/L (sensitivity 74.3%, specificity 71.0%) and 0.873 (sensitivity 70.1%, specificity 73.4%), respectively, for women, and 1.275 mmol/L (sensitivity 66.7%, specificity 74.4%) and 0.812 (sensitivity 75.8%, specificity 69.2%), respectively, for men.

CONCLUSION

TG and TG/HDL-C ratio could be used to identify IR in urban middle-aged and older non-obese Chinese without diabetes.

Glucagon-like peptide 1 protects microvascular endothelial cells by inactivating the PARP-1/iNOS/NO pathway

Increasing studies suggest that the activity of GLP-1 might be of significant importance in the development of type 2 diabetes beyond its serum glucose-lowering effects. However, to date, the anti-apoptosis mechanism by which GLP-1 acts on MILE SVEN 1 (MS-1) cells has not been fully explored with regard to the intracellular signaling pathway. Increasing evidence shows that apoptosis of islet microvascular endothelial cells (IMECs) participates in the pathogenesis of diabetes. We wondered whether GLP-1 exerts its anti-apoptosis effects by inactivating the PARP-1/iNOS/NO pathway in oxidized low-density-lipoprotein (oxLDL)-induced apoptosis in mouse IMECs (MS-1 cells), which may linked to GLP-1R/cAMP levels. MTT assay revealed that 2-h pre-incubation with GLP-1 markedly restored the oxLDL-induced loss of MS-1 viability in a concentration-dependent manner. This effect was accompanied by a significant decrease in intracellular nitric oxide (NO) activity. Moreover, GLP-1 suppressed lipid peroxidation, restored the activities of endogenous antioxidants, and decreased the level of NO. Pre-incubating MS-1 cells with GLP-1 reduced cell apoptosis. Finally, GLP-1 could efficiently prevent the upregulation of poly(ADP-ribose) polymerase-1/nitrotyrosine and inducible NO synthase protein. Simultaneously, the expression of GLP-1 receptor and the level of cAMP was consistent with the administration of GLP-1. Our findings suggest that GLP-1 can effectively protect MS-1 cells against oxLDL-induced apoptosis, which may be important in preventing the pathogenesis of diabetes mellitus.

Metformin reduces intracellular reactive oxygen species levels by upregulating expression of the antioxidant thioredoxin via the AMPK-FOXO3 pathway

BACKGROUND

Oxidative stress induced by free fatty acids plays a critical role in the pathogenesis of endothelial dysfunction and atherosclerosis in patients with metabolic syndrome. Reducing oxidative stress in these patients may prevent cardiovascular complications. The antidiabetic agent metformin has been reported to directly protect the cardiovascular system. In this study, we examined the effect of metformin on the intracellular levels of reactive oxygen species (ROS) induced by palmitic acid (PA) in human aortic endothelial cells and studied the molecular mechanisms involved.

METHODS AND RESULTS

We observed that metformin significantly reduced intracellular ROS levels induced by PA. Additionally, metformin increased the expression of the antioxidant thioredoxin (Trx), which mediated metformin's effects on ROS reduction. Metformin increased Trx expression through the AMP-activated protein kinase (AMPK) pathway. Metformin-regulated Trx at the transcriptional level and forkhead transcription factor 3 (FOXO3) was involved in this process.

CONCLUSION

These results suggest that metformin reduces ROS levels by inducing Trx expression through activation of the AMPK-FOXO3 pathway.

Adiponectin reduces glucotoxicity-induced apoptosis of INS-1 rat insulin-secreting cells on a microfluidic chip

Diabetes mellitus is a metabolic disorder characterized by elevated blood sugar and progressive failure of insulin-producing beta-cells. Persistent hyperglycemia and blood sugar fluctuation are two general phenomena in diabetic patients, and both of them can result in an increased frequency of beta-cell apoptosis. Therefore, rescuing pancreatic beta-cells from glucotoxicity-induced beta-cell apoptosis is increasing viewed as a promising means for curing. The aim of this study was to investigate whether adiponectin, an important cytokine expressed in adipose tissue, has a potential for the application as the antiapoptotic strategy. INS-1 rat insulin-secreting cell line was used in this study as a model of pancreatic beta-cells, because INS-1 cells show the susceptibility to glucotoxicity, as seen in beta-cells. INS-1 cells were cultured on a novel microfluidic chip with persistent perfusion and subsequently exposed to sustained high glucose (SHG) (25 mmol/l) or intermittent high glucose (IHG) (11.1 and 25 mmol/l glucose alternating every 12 h) in the absence or presence of adiponectin for 72 h. Using this device, we showed that IHG induced more serious impairment in INS-1 cells than did SHG, and adiponectin partially rescued INS-1 cells from glucotoxicity-induced apoptosis, dysfunction and reduction of insulin gene expression. Simultaneously, the mRNA expression of AMP-activated protein kinase (AMPK), which is a signaling protein that acts to modulate glucose uptake in skeletal muscle, was restored in the presence of adiponectin. Based on the above evidence, we suggest that adiponectin could reduce glucotoxicity-induced apoptosis of beta-cells, at least in part, by transiently activating AMPK signaling pathway.

[Therapeutic effects of (131)I therapy on hyperthyroidism in adolescents and adults: a comparative study]

OBJECTIVE

To investigate the efficacy and safety of (131)I therapy on hyperthyroidism in adolescents, middle-aged people, and the elderly.

METHODS

940 patients with hyperthyroidism, 106 aged < 25 (Group A, group of young people), 768 aged 25 - 60 (Group B, middle-aged group), and 66 aged > 60 (Group C, group of the elderly), underwent (131)I therapy and were followed up for 2 years to evaluate the efficacy and safety.

RESULTS

Forty-six patients in group A (43.4%) became euthyroid, 34(32.1%) turned better, 24 (22.6%) suffered from hypothyroidism, and 2 (1.9%) remained un-changed, with a general effective rate of 98.11% (104/106). 346 patients (45.1%) in Group B became euthyroid, 260 (33.9%) turned better, 140 (18.2%) suffered from hypothyroidism, and 22 (2.9%) remained un-changed, with a general effective rate of 97.14% (746/768). And 28 patients (42.4%)in Group C became euthyroid, 24 (36.4%) turned better, 10 (15.15%) suffered from hypothyroidism, and 4 (6.1%) remained unchanged, with a general effective rate of 93.93% (62/66). There were not significant differences in the recovery rate, improvement rate, hypothyroidism rat, and ineffective rate among the 3 groups (all P > 0.05).

CONCLUSION

There are no significant differences in the efficacy and safety of (131)I therapy in hyperthyroidism on the patients of different ages, including adolescent, adult and elder persons. (131)I therapy is safe and effective for adolescents.

Influence of blood glucose on the expression of glucose trans-porter proteins 1 and 3 in the brain of diabetic rats

BACKGROUND

The delivery of glucose from the blood to the brain involves its passage across the endothelial cells of the blood-brain barrier (BBB), which is mediated by the facilitative glucose transporter protein 1 (GLUT(1)), and then across the neural cell membranes, which is mediated by GLUT(3). This study aimed to evaluate the dynamic influence of hyperglycemia on the expression of these GLUTs by measuring their expression in the brain at different blood glucose levels in a rat model of diabetes. This might help to determine the proper blood glucose threshold level in the treatment of diabetic apoplexy.

METHODS

Diabetes mellitus was induced with streptozotocin (STZ) in 30 rats. The rats were randomly divided into 3 groups: diabetic group without blood glucose control (group DM1), diabetic rats treated with low dose insulin (group DM2), and diabetic rats treated with high dose insulin (group DM3). The mRNA and protein levels of GLUT(1) and GLUT(3) were assayed by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively.

RESULTS

Compared with normal control rats, the GLUT(1) mRNA was reduced by 46.08%, 29.80%, 19.22% (P < 0.01) in DM1, DM2, and DM3 group, respectively; and the GLUT(3) mRNA was reduced by 75.00%, 46.75%, and 17.89% (P < 0.01) in DM1, DM2, and DM3 group, respectively. The abundance of GLUT(1) and GLUT(3) proteins had negative correlation with the blood glucose level (P < 0.01). The density of microvessels in the brain of diabetic rats did not change significantly compared with normal rats.

CONCLUSIONS

Chronic hyperglycemia downregulates GLUT(1) and GLUT(3) expression at both mRNA and protein levels in the rat brain, which is not due to the decrease of the density of microvessels. The downregulation of GLUT(1) and GLUT(3) expression might be the adaptive reaction of the body to prevent excessive glucose entering the cell that may lead to cell damage.

Differentiation of bone marrow-derived mesenchymal stem cells from diabetic patients into insulin-producing cells in vitro

BACKGROUND

Stem cells, which have the ability to differentiate into insulin-producing cells (IPCs), would provide a potentially unlimited source of islet cells for transplantation and alleviate the major limitations of availability and allogeneic rejection. Therefore, the utilization of stem cells is becoming the most promising therapy for diabetes mellitus (DM). Here, we studied the differentiation capacity of the diabetic patient's bone marrow-derived mesenchymal stem cells (MSCs) and tested the feasibility of using MSCs for beta-cell replacement.

METHODS

Bone marrow-derived MSCs were obtained from 10 DM patients (5 type 1 DM and 5 type 2 DM) and induced to IPCs under a three-stage protocol. Representative cell surface antigen expression profiles of MSCs were analysed by flow cytometric analysis. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect multiple genes related to pancreatic beta-cell development and function. The identity of the IPCs was illustrated by the analysis of morphology, ditizone staining and immunocytochemistry. Release of insulin by these cells was confirmed by immunoradioassay.

RESULTS

Flow cytometric analysis of MSCs at passage 3 showed that these cells expressed high levels of CD29 (98.28%), CD44 (99.56%) and CD106 (98.34%). Typical islet-like cell clusters were observed at the end of the protocol (18 days). Ditizone staining and immunohistochemistry for insulin were both positive. These differentiated cells at stage 2 (10 days) expressed nestin, pancreatic duodenal homeobox-1 (PDX-1), Neurogenin3, Pax4, insulin, glucagon, but at stage 3 (18 days) we observed the high expression of PDX-1, insulin, glucagon. Insulin was secreted by these cells in response to different concentrations of glucose stimulation in a regulated manner (P<0.05).

CONCLUSIONS

Bone marrow-derived MSCs from DM patients can differentiate into functional IPCs under certain conditions in vitro. Using diabetic patient's own bone marrow-derived MSCs as a source of autologous IPCs for beta-cell replacement would be feasible.

Depressive symptoms and risk factors in Chinese persons with type 2 diabetes

BACKGROUND

Our objective was to study depressive symptoms and potential risk factors in Chinese persons with type 2 diabetes.

METHODS

Zung self-rating depression scale (ZSDS) was used to scan depressive symptoms. Correlation between depressive symptoms and sociodemographic and medical factors were analyzed by logistic regression.

RESULTS

Of 222 patients with type 2 diabetes (115 males, 107 females, age 56.36 +/- 12.67 years, disease duration 7.36 +/- 6.32 years), a total of 51 (23.0%) patients were categorized as having depressive symptoms. Percentage of depressive symptoms in females was higher than in males (29.0% vs. 17.6%, chi(2)=4.2, p <0.05). Percentage of depressive symptoms increased with increase of diabetes duration, HbA(1c), TC, TG, and number of chronic diabetic complications. Univariate logistic regression showed that diabetes duration, number of chronic diabetic complications, HbA(1c), female gender, and TC were significantly correlated with depressive symptoms (p <0.05). Multivariate logistic regression analysis indicated that variables, i.e., diabetes duration, number of chronic diabetic complications, HbA(1C), and female gender were significantly and independently associated with depressive symptoms (p <0.05).

CONCLUSIONS

In this Chinese population, depressive symptoms in subjects with type 2 diabetes were frequent. Diabetes duration, number of chronic diabetic complications, HbA(1C), and female gender were independent risk factors for depressive symptoms. Further research on the relationship between diabetes and depressive symptoms in China was necessary.

Distribution of Staphylococcus species among human clinical specimens and emended description of Staphylococcus caprae

By DNA-DNA hybridization on microplates, we identified 1,230 strains of staphylococci from human clinical specimens and determined the distribution of species. The 10 Staphylococcus species isolated most often were S. epidermidis (31.3%), S. aureus (23.3%), S. haemolyticus (12.2%), S. caprae (10.7%), S. simulans (4.4%), S. hominis (4.0%), S. capitis (3.9%), S. saprophyticus (3.6%), S. warneri (2.2%), and S. lugdunensis (1.3%). From these results, we realized that S. caprae strains were widely distributed in human clinical specimens. The description in Bergey's Manual of Systematic Bacteriology indicates that no strains of S. caprae produce acid from fructose and mannitol, but all our S. caprae strains produced acid from fructose and mannitol. Consequently, many strains of S. caprae isolated from human clinical specimens have been misidentified as S. haemolyticus or S. hominis by conventional biochemical tests. In this paper, we propose an emended description of S. caprae.

Streptococcus peroris sp. nov. and Streptococcus infantis sp. nov., new members of the Streptococcus mitis group, isolated from human clinical specimens

Taxonomic studies were performed on eight strains of alpha-haemolytic streptococci that showed very low DNA-DNA hybridization similarity values with all established members of the mitis group of the genus Streptococcus. These strains were isolated from the tooth surface and pharynx of humans. 16S rRNA gene sequence analysis showed that these strains belonged to the mitis group, but that they fell into two new branches. DNA-DNA hybridization demonstrated two new similarity groups. From the results of the present study, the names Streptococcus peroris sp. nov. and Streptococcus infantis sp. nov. are proposed for these new groups. The type strains are O-66T (= GTC 848T = JCM 10158T) and O-122T (= GTC 849T = JCM 10157T), respectively.

Description of Arthrobacter creatinolyticus sp. nov., isolated from human urine

Three strains of creatinine-hydrolysing bacteria isolated from human urine were characterized taxonomically. They were aerobic, non-spore-forming, Gram-positive rods with the peptidoglycan of the cell wall containing lysine. MK-8 and MK-9 were found to be the major types of menaquinone. The G + C content of the DNA was 66-67 mol%. The 16S rRNA sequence of one strain (GIFU 12498) was determined and aligned with other high-G + C-content Gram-positive rods from different genera. Following phylogenetic analysis, this strain was placed in the genus Arthrobacter. Arthrobacter protophormiae was the most closely related species in the phylogenetic tree, and this species also showed the highest sequence homology value (97%) with GIFU 12498. However, DNA-DNA hybridization indicated that GIFU 12498 did not belong to A. protophormiae (33.8 +/- 3.5% chromosomal similarity). The three urine strains belonged to one species because they shared more than 95% DNA-DNA similarity. It is proposed that these strains are placed in the genus Arthrobacter as a new species, Arthrobacter creatinolyticus sp. nov. The type strain of A. creatinolyticus is GIFU 12498, which has been deposited in the Japan Collection of Microorganisms (JCM) with the accession number JCM 10102.

Determination of 23S rRNA sequences from members of the genus Streptococcus and characterization of genetically distinct organisms previously identified as members of the Streptococcus anginosus group

The 23S rRNA gene sequences of eight type strains of the genus Streptococcus were determined. Three species-specific probes for the three members of the Streptococcus anginosus group and one group-specific probe for these three species were designed. The PCR-amplified 23S rRNA gene sequences of 28 clinical strains were examined by hybridization with the four oligonucleotide probes. They were suspected to be members of the S. anginosus group by biochemical tests; however, only 21 strains (75%) hybridized to one of the three species probes. Seven biochemically atypical strains did not hybridize to these species-specific probes. Of the seven strains, three hybridized to the group-specific probe. The 23S ribosomal RNA sequences of these three strains differed by three bases within the 20-base probe area of S. anginosus. The phylogenetic tree of the 16S rRNA of these three strains located them within the branch of S. anginosus. The remaining four strains, which did not hybridize to group- or species-specific probes, had a raffinose-positive and VP-negative phenotype. The probe hybridization results showed that these four strains did not belong to the S. anginosus group and were closely related to S. parasanguis according to partial sequences of their 16S rRNA genes.

Genetic identification of members of the genus Corynebacterium at genus and species levels with 16S rDNA-targeted probes

16S rRNA gene-targeted probes were designed for the identification of corynebacteria at the genus and species levels. The genus-specific probe hybridized all clinically important members of the genus Corynebacterium and could distinguish them from other coryneform bacteria and phylogenetically related high G+C% gram-positive bacteria, including Actinomyces, Rhodococcus, Gordona, Nocardia, Streptomyces, Brevibacterium and Mycobacterium. The species-specific probes for C. jeikeium and C. diphtheriae could differentiated these two species from other members of this genus. The probes were used to select corynebacteria among gram-positive clinical isolates which had been tentatively identified as corynebacteria by biochemical tests. We screened 59 strains with the genus-specific probe; 51 strains hybridized to the genus-specific probe, 8 did not. Of the 51 strains that hybridized to the genus-specific probe, 1 hybridized to the C. diphtheriae species probe and 13 hybridized to the C. jeikeium species probe. The 8 strains that did not hybridize to the genus probe were further characterized by analyzing cell wall diaminopimelic acid and partial 16S rRNA sequencing. The results indicated that these strains were distributed in the genera Arthrobacter and Brevibacterium.

Transfer of Streptococcus adjacens and Streptococcus defectivus to Abiotrophia gen. nov. as Abiotrophia adiacens comb. nov. and Abiotrophia defectiva comb. nov., respectively

We performed this study to determine the 16S rRNA sequences of the type strains of Streptococcus adjacens and Streptococcus defectivus and to calculate the phylogenetic distances between these two nutritionally variant streptococci (NVS) and other members of the genus Streptococcus. S. adjacens and S. defectivus belonged to one cluster, but this cluster was not closely related to other streptococcal species. A comparative analysis of the sequences of these organisms and other low-G+C-content gram-positive bacteria revealed that the two NVS species formed a distinct cluster and were only remotely related to the Aerococcus and Carnobacterium clusters. The highest level of homology (93.7%) was found between S. adjacens and Carnobacterium divergens. Carnobacterium species have meso-diaminopimelic acid in their cell walls, but S. adjacens and S. defectivus have L-lysine as the diamino acid at position 3 in their peptidoglycan tetrapeptides. On the basis of our findings and the results of previous phenotypic studies, we propose that the NVS species should be placed in a new genus, the genus Abiotrophia, as Abiotrophia adiacens comb. nov. and Abiotrophia defectiva comb. nov.

Determination of 16S rRNA sequences of Streptococcus mitis and Streptococcus gordonii and phylogenetic relationships among members of the genus Streptococcus

We determined the 16S rRNA sequences of the type strains of Streptococcus mitis and Streptococcus gordonii and calculated the phylogenetic distances between those organisms and other members of the genus Streptococcus. The viridans group streptococci were separated into five phylogenetic groups; we named these groups the anginosus group, the mitis group, the salivarius group, the bovis group, and the mutans group. S. mitis and S. gordonii clustered in the mitis group together with Streptococcus pneumoniae, Streptococcus oralis, Streptococcus sanguis, and Streptococcus parasanguis at levels of sequence homology of more than 96%. Within this group, S. mitis, S. oralis, and S. pneumoniae exhibited more than 99% sequence homology with each other, although the DNA-DNA similarity values for their total chromosome DNAs were less than 60%.