No abstract

In the presence of obesity, beta-cell mass needs to be increased to compensate for the accompanying demands and maintain euglycemia. However, in Korea, the majority of type 2 diabetic patients are nonobese. We determined the absolute masses, relative volumes, and ratio of alpha- and beta-cell in the pancreas and islets in normal and diabetic Korean subjects to correlate these findings with the clinical characteristics. Whole pancreases procured from organ donors were divided into 24 parts (control 1, n = 9). Tissue was also obtained by surgical resection after 35 partial pancreatectomies: in 25 diabetic patients, 10 age- and body mass index (BMI)-matched patients of benign or malignant pancreatic tumor without diabetes mellitus (DM) (control 2). Morphometric quantifications were performed. In control 1, the relative volume of beta-cells was 2.1 +/- 0.9%, and the total beta-cell mass was 1.3 +/- 0.3 g. The relative volume of beta-cells was found to be variable (control 1, 2.1 +/- 0.9%; control 2, 1.9 +/- 0.7%; DM, 1.4 +/- 1.0%; P < 0.05 DM vs. control 1 and 2) and showed good correlation with BMI (control 1, r(2) = 0.64; DM, r(2) = 0.55; all subjects, r(2) = 0.38; P < 0.05). Notably, in type 2 diabetic patients, the ratio of alpha-cell area to beta-cell area in the islet was higher than in control 1 and 2 (0.81 +/- 0.4 vs. 0.29 +/- 0.2, 0.20 +/- 0.1, P < 0.05). Additionally, significant alpha-cell expansion and a decreased beta-cell fraction were predominantly observed in larger islets (islet area, >6415 micro m(2); P < 0.05) in control 1 and diabetic patients. The relative volume of beta-cell was found to be correlated with BMI in diabetic patients and normal organ donors. Moreover, decreased beta-cell but increased alpha-cell proportion in the islets suggests for a selective beta-cell loss in the pathogenesis of Korean type 2 diabetes.

We report for the first time that a positive serum TgAb test was an independent predictor for thyroid malignancy in thyroid nodules along with serum TSH levels regardless of the presence of AIT. Our results suggest that TgAb measurement could give additional information for predicting malignancy in cytologically indeterminate thyroid nodules in conjunction with clinical risk factors and TSH levels.

Aims/hypothesis Asians have a propensity to develop type 2 diabetes with a lower BMI than Western populations. This discrepancy may be due to differences in body fat and muscle mass for a given BMI. However, unlike adiposity, it is unclear whether muscle mass affects the risk of type 2 diabetes in Asian populations. Methods We conducted a 2-yearly prospective assessment of 6895 participants who were free of diabetes at the baseline examination as part of the Korean Genome Epidemiology Study. The muscle mass index (MMI) was defined as the weightadjusted appendicular skeletal muscle mass. Using Cox regression models, we evaluated the association between MMI and the risk of developing type 2 diabetes across sex-specific tertiles of MMI. Low muscle mass was defined as the sex-specific lowest tertile of MMI. Main covariates included age, sex, urban or rural residence, family history of diabetes, hypertension, smoking status, education level, monthly income, physical activity, alcohol consumption and diet. In addition, body fat mass, waist circumference and BMI were controlled as categorical variables. Obesity was defined as a BMI of ≥25 kg/m 2 or a waist circumference of ≥90 cm for men and ≥85 cm for women. Results During a median follow-up of 9.06 years, 1336 participants developed type 2 diabetes. At baseline, the mean age was 52.1 years and the mean BMI was 24.4 kg/m 2 . The mean MMI for men and women was 32.1% and 26.0%, respectively. There was an inverse association between MMI and the risk of type 2 diabetes. Multivariate-adjusted HRs for the risk of developing type 2 diabetes were 2.05 (95% CI 1.73, 2.43), 1.39 (95% CI 1.17, 1.66) and 1.0 from the lowest to highest sex-specific MMI tertile, with an HR of 1.35 (95% CI 1.26, 1.45) per SD decline in MMI. Further adjustments for fat mass, waist circumference and BMI as categorical variables did not modify the relationship (each p < 0.01). In BMI-stratified analyses, the population-attributable fraction of the lowest tertile of MMI for developing type 2 diabetes was increased by 11.9% in the nonobese group and 19.7% in the obese group. Conclusions/interpretation Low muscle mass as defined by MMI was associated with an increased risk of type 2 diabetes, independent of general obesity, in middle-aged and older Korean adults.

We found a strong inverse association of 25(OH)D levels with MetS and HTN in this middle-aged Korean population. Having vitamin D deficiency was associated with an increased risk of having MetS and HTN in this demographic group.

Statins have been postulated to affect the bone metabolism. Recent experimental and epidemiologic studies have suggested that statins may also have bone protective effects. This study assessed the effects of simvastatin on the proliferation and differentiation of human bone marrow stromal cells (BMSCs) in an ex vivo culture. The bone marrow was obtained from healthy donors. Mononuclear cells were isolated and cultured to osteoblastic lineage. In the primary culture, 10-6 M simvastatin diminished the mean size of the colony forming units-fibroblastic (CFU-Fs) and enhanced matrix calcification. At near confluence, the cells were sub-cultured. Thereafter, the alkaline phosphatase (ALP) activities of each group were measured by the time course of the secondary culture. Simvastatin increased the ALP activity in a dose dependent manner, and this stimulatory effect was more evident during the early period of culture. A 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay was performed during the secondary culture in order to estimate the effect of simvastatin on the proliferation of human BMSCs. When compared to the control group, simvastatin significantly decreased the proliferation of cells of each culture well. 10-6 M of simvastatin also significantly enhanced the osteocalcin mRNA expression level. This study shows that simvastatin has a stimulatory effect on bone formation through osteoblastic differentiation, and has an inhibitory effect on the proliferative potential of human BMSCs

Our results identified this sonographic classification as a useful tool in the differentiation of malignant nodules from benign nodules. In view of the high negative predictive value of sonographic classification, a more aggressive approach is recommended only for category 3 nodules.

There is increasing evidence that the retinoic acid receptor-related orphan receptor a (RORa) plays an important role in the regulation of metabolic pathways, particularly of fatty acid and cholesterol metabolism; however, the role of RORa in the regulation of hepatic lipogenesis has not been studied. Here, we report that RORa attenuates hepatic steatosis, probably via activation of the adenosine monophosphate (AMP)-activated protein kinase (AMPK) and repression of the liver X receptor a (LXRa). First, RORa and its activator, cholesterol sulfate (CS), induced phosphorylation of AMPK, which was accompanied by the activation of serine-threonine kinase liver kinase B1 (LKB1). Second, the activation of RORa, either by transient transfection or CS treatment, decreased the TO901317-induced transcriptional expression of LXRa and its downstream target genes, such as the sterol regulatory element binding protein-1 (SREBP-1) and fatty acid synthase. RORa interacted physically with LXRa and inhibited the LXRa response element in the promoter of LXRa, indicating that RORa interrupts the autoregulatory activation loop of LXRa. Third, infection with adenovirus encoding RORa suppressed the lipid accumulation that had been induced by a free-fatty-acid mixture in cultured cells. Furthermore, we observed that the level of expression of the RORa protein was decreased in the liver of mice that were fed a high-fat diet. Restoration of RORa via tail-vein injection of adenovirus (Ad)-RORa decreased the high-fat-diet-induced hepatic steatosis. Finally, we synthesized thiourea derivatives that activated RORa, thereby inducing activation of AMPK and repression of LXRa. These compounds decreased hepatic triglyceride levels and lipid droplets in the high-fat-diet-fed mice. Conclusion: We found that RORa induced activation of AMPK and inhibition of the lipogenic function of LXRa, which may be key phenomena that provide the beneficial effects of RORa against hepatic steatosis. (HEPATOLOGY 2012;55:1379-1388 A n increasing number of populations in the world suffer from fatty liver, which is a disease defined as hepatic fat accumulation greater than 5% of the liver wet weight. The major causes of fatty liver are obesity, diabetes, hyperlipidemia, drugs, and metabolic disorders.1 Although this relativelyAbbreviations: ACC, acetyl-CoA carboxylase; Ad-RORa, adenovirus-RORa; AICAR, aminoimidazole carboxamide ribonucleotide; AKT2, v-akt murine thymoma viral oncogene homolog 1; AMPK, adenosine monophosphate (AMP)-activated protein kinase; ATP, adenosine triphosphate; BODIPY, borondipyrromethene; CA-AMPK, constitutively active AMPK; ChIP, chromatin immunoprecipitation; CS, cholesterol sulfate; Cyp7b1, oxysterol 7a-hydroxylase; DBD, DNA binding domain; FA, fatty acid; FAS, fatty acid synthase; FFA, free fatty acid; HFD, high-fat diet; LBD, ligand binding domain; LKB1, serine-threonine kinase liver kinase B1; LXRa, liver X receptor a; LXRE, LXR response element; NADH, reduced nicotinamide adenine dinucleotide; p, phosphorylated; RORa, retinoic acid rec...