Assessment of Molecular Subtypes in Thyrotoxic Periodic Paralysis and Graves Disease Among Chinese Han Adults: A Population-Based Genome-Wide Association Study.

Importance: Thyrotoxic periodic paralysis (TPP) is a potentially lethal complication of hyperthyroidism. However, only 1 specific susceptibility locus for TPP has been identified. Additional genetic determinants should be detected so that a prediction model can be constructed. Objective: To investigate the genetic architecture of TPP and distinguish TPP from Graves disease cohorts. Design, Setting, and Participants: This population-based case-control study used a 2-stage genome-wide association study to investigate the risk loci of TPP and weighted genetic risk score to construct a TPP prediction model with data from a Chinese Han population recruited in hospitals in China from March 2003 to December 2015. The analysis was conducted from November 2014 to August 2016. Main Outcomes and Measures: Loci specifically associated with TPP risk and those shared with Graves disease and prediction model of joint effects of TPP-specific loci. Results: A total of 537 patients with TPP (mean [SD] age, 35 [11] years; 458 male) 1519 patients with Graves disease and no history of TPP (mean [SD] age, 38 [13] years; 366 male), and 3249 healthy participants (mean [SD] age, 46 [10] years; 1648 male) were recruited from the Han population by hospitals throughout China. Two new TPP-specific susceptibility loci were identified: DCHS2 on 4q31.3 (rs1352714: odds ratio [OR], 1.58; 95% CI, 1.35-1.85; P = 1.24 × 10-8) and C11orf67 on 11q14.1 (rs2186564: OR, 1.50; 95% CI, 1.29-1.74; P = 2.80 × 10-7). One previously reported specific locus was confirmed on 17q24.3 near KCNJ2 (rs312729: OR, 2.08; 95% CI, 1.83-2.38; P = 8.02 × 10-29). Meanwhile, 2 risk loci (MHC and Xq21.1) were shared by Graves disease and TPP. After 2 years of treatment, the ratio of persistent thyrotropin receptor antibody positivity was higher in patients with TPP than in patients with Graves disease and no history of TPP (OR, 3.82; 95% CI, 2.04-7.16; P = 7.05 × 10-6). The prediction model using a weighted genetic risk score and 11 candidate TPP-specific single-nucleotide polymorphisms had an area under the curve of 0.80. Conclusions and Relevance: These findings provide evidence that TPP is a novel molecular subtype of Graves disease. The newly identified loci, along with other previously reported loci, demonstrate the growing complexity of the heritable contribution to TPP pathogenesis. A complete genetic architecture will be helpful to understand the pathophysiology of TPP, and a useful prediction model could prevent the onset of TPP.

Genome-wide association study identifies a novel susceptibility gene for serum TSH levels in Chinese populations.

Thyroid-stimulating hormone (TSH) is a sensitive indicator of thyroid function. High and low TSH levels reflect hypothyroidism and hyperthyroidism, respectively. Even within the normal range, small differences in TSH levels, on the order of 0.5-1.0 mU/l, are associated with significant differences in blood pressure, BMI, dyslipidemia, risk of atrial fibrillation and atherosclerosis. Most of the variance in TSH levels is thought to be genetically influenced. We conducted a genome-wide association study of TSH levels in 1346 Chinese Han individuals. In the replication study, we genotyped four candidate SNPs with the top association signals in an independent isolated Chinese She cohort (n = 3235). We identified a novel serum TSH susceptibility locus within XKR4 at 8q12.1 (rs2622590, Pcombined = 2.21 × 10(-10)), and we confirmed two previously reported TSH susceptibility loci near FOXE1 at 9q22.33 and near CAPZB at 1p36.13, respectively. The rs2622590_T allele at XKR4 and the rs925489_C allele near FOXE1 were correlated with low TSH levels and were found to be nominally associated to patients with papillary thyroid carcinoma (PTC) (OR = 1.41, P= 0.014 for rs2622590_T, and OR = 1.61, P= 0.030 for rs925489_C). The rs2622590 and rs925489 genotypes were also correlated with the expression levels of FOXE1 and XKR4, respectively, in PTC tissues (P = 2.41 × 10(-4) and P= 0.02). Our findings suggest that the SNPs in XKR4 and near FOXE1 are involved in the regulation of TSH levels.

Robust evidence for five new Graves' disease risk loci from a staged genome-wide association analysis.

Graves' disease (GD), characterized by autoantibodies targeting antigens specifically expressed in thyroid tissues causing hyperthyroidism, is triggered by a combination of genetic and environmental factors. However, only a few loci for GD risk were confirmed in the various ethnic groups, and additional genetic determinants have to be detected. In this study, we carried out a three-stage study in 9529 patients with GD and 9984 controls to identify new risk loci for GD and found genome-wide significant associations in the overall populations for five novel susceptibility loci: the GPR174-ITM2A at Xq21.1, C1QTNF6-RAC2 at 22q12.3-13.1, SLAMF6 at 1q23.2, ABO at 9q34.2 and an intergenic region harboring two non-coding RNAs at 14q32.2 and one previous indefinite locus, TG at 8q24.22 (Pcombined < 5 × 10(-8)). The genotypes of corresponding variants at 14q32.2 and 8q24.22 were correlated with the expression levels of C14orf64 and a TG transcript skipping exon 46, respectively. This study increased the number of GD loci with compelling evidence and indicated that non-coding RNAs might be potentially involved in the pathogenesis of GD.

An independent positive relationship between the serum total osteocalcin level and fat-free mass in healthy premenopausal women.

CONTEXT: It is widely reported that osteocalcin is negatively associated with fat mass. However, there are few reports describing its correlation with fat-free mass, particularly in women. OBJECTIVES: The objective of the current study was to investigate the possible relationship between osteocalcin and fat-free mass in healthy, nonobese women. DESIGN AND SETTING: This study was performed in a tertiary university teaching hospital. SUBJECTS: A total of 504 healthy women aged 20-75 years were enrolled. MAIN OUTCOME MEASURES: Body composition was measured using a bioelectronics impedance analyzer. The serum concentrations of total osteocalcin, estradiol, leptin, osteoprotegerin, the receptor activator of nuclear factor-κB ligand, IGF-I, fasting plasma glucose, and urinary N-terminal telopeptide of type I collagen were tested. The bone mineral densities (BMDs) at the lumbar spine and proximal femoral neck were measured by dual-energy X-ray absorptiometry. RESULTS: The serum total osteocalcin level had a significant positive association with fat-free mass (r = 0.168, P = .007) after adjusting for age, fat mass, menopausal status, estradiol, fasting glucose, leptin, osteoprotegerin, receptor activator of nuclear factor-κB ligand, IGF-I, N-terminal telopeptide of type I collagen, BMDs, and waist and hip circumference. Analysis in pre- and postmenopausal women demonstrated that this association was only present in premenopausal women (r = 0.190, P = .005). The multiple stepwise regression analysis revealed that hip circumference, femoral neck-BMD, fat mass, leptin, osteocalcin, and age are the contributors to the changes in fat-free mass in premenopausal women (adjusted R(2) = 0.521, P < .001). CONCLUSION: The serum level of total osteocalcin was positively associated with fat-free mass independent of age, fat mass, leptin, and other confounders in premenopausal women.

A refined study of FCRL genes from a genome-wide association study for Graves' disease.

To pinpoint the exact location of the etiological variant/s present at 1q21.1 harboring FCRL1-5 and CD5L genes, we carried out a refined association study in the entire FCRL region in 1,536 patients with Graves' disease (GD) and 1,516 sex-matched controls by imputation analysis, logistic regression, and cis-eQTL analysis. Among 516 SNPs with P<0.05 in the initial GWAS scan, the strongest signals associated with GD and correlated to FCRL3 expression were located at a cluster of SNPs including rs7528684 and rs3761959. And the allele-specific effects for rs3761959 and rs7528684 on FCRL3 expression level revealed that the risk alleles A of rs3761959 and C of rs7528684 were correlated with the elevated expression level of FCRL3 whether in PBMCs or its subsets, especially in CD19(+) B cells and CD8(+) T subsets. Next, the combined analysis with 5,300 GD cases and 4,916 control individuals confirmed FCRL3 was a susceptibility gene of GD in Chinese Han populations, and rs3761959 and rs7528684 met the genome-wide association significance level (P(combined) = 2.27×10(-12) and 7.11×10(-13), respectively). Moreover, the haplotypes with the risk allele A of rs3761959 and risk allele C of rs7528684 were associated with GD risk. Finally, our epigenetic analysis suggested the disease-associated C allele of rs7528684 increased affinity for NF-KB transcription factor. Above data indicated that FCRL3 gene and its proxy SNP rs7528684 may be involved in the pathogenesis of GD by excessive inhibiting B cell receptor signaling and the impairment of suppressing function of Tregs.

The effects of bisphenol A (BPA) exposure on fat mass and serum leptin concentrations have no impact on bone mineral densities in non-obese premenopausal women.

OBJECTIVES: Bisphenol A (BPA) exposure may promote obesity, but its effect on bone mineral density (BMD) has not been reported in humans. We aimed to examine the relationships between BPA exposure, body composition, serum estradiol, leptin, osteocalcin levels and BMDs in healthy premenopausal women. DESIGN AND METHODS: In this cross-sectional study, a total of 246 healthy premenopausal women aged 20 years and older with regular menstrual cycles were investigated. Body mass index (BMI), fat mass, fat-free mass and BMDs were measured by DXA. Serum estradiol, leptin, osteocalcin, urinary BPA and NTx levels were also tested. RESULTS: Urinary BPA levels were positively associated with fat mass (r=0.193, p=0.006) and leptin (r=0.236, p=0.001) but not with fat-free mass after adjusting for age and BMI. BPA was not associated with serum estradiol levels, BMDs, or bone resorption marker NTx and bone formation parameter osteocalcin, either. A multivariate stepwise regression analysis confirmed that serum leptin levels were positively influenced by fat mass (ß=0.746, p<0.001) and BPA (ß=0.127, p=0.01) but negatively correlated with fat-free mass (ß=-0.196, p<0.001). However, the changes of BMDs at the lumbar spine (ß=0.298, p<0.001) and femoral neck (ß=0.305, p<0.001) were primarily explained by fat-free mass, and were irrelevant of the fat mass, leptin or BPA exposure. CONCLUSIONS: Although BPA exposure is related with increased amount of fat mass and elevated serum leptin levels, it has neutral effect on BMDs in premenopausal women, possibly due to the exclusive role of fat-free mass, which is unrelated to BPA in determining BMDs.

A genome-wide association study identifies two new risk loci for Graves' disease.

Graves' disease is a common autoimmune disorder characterized by thyroid stimulating hormone receptor autoantibodies (TRAb) and hyperthyroidism. To investigate the genetic architecture of Graves' disease, we conducted a genome-wide association study in 1,536 individuals with Graves' disease (cases) and 1,516 controls. We further evaluated a group of associated SNPs in a second set of 3,994 cases and 3,510 controls. We confirmed four previously reported loci (in the major histocompatibility complex, TSHR, CTLA4 and FCRL3) and identified two new susceptibility loci (the RNASET2-FGFR1OP-CCR6 region at 6q27 (P(combined) = 6.85 × 10(-10) for rs9355610) and an intergenic region at 4p14 (P(combined) = 1.08 × 10(-13) for rs6832151)). These newly associated SNPs were correlated with the expression levels of RNASET2 at 6q27, of CHRNA9 and of a previously uncharacterized gene at 4p14, respectively. Moreover, we identified strong associations of TSHR and major histocompatibility complex class II variants with persistently TRAb-positive Graves' disease.

Two unusual cases of intractable hyperthyroidism responsive to octreotide: Munchausen syndrome or not?

BACKGROUND: The effective treatment for patients with resistant hyperthyroidism is difficult. METHODS: In this case report with 4-year follow-up data, we present 2 unusual cases of hyperthyroidism that were unresponsive to almost all antithyroid treatments including total thyroidectomy, but both were controlled with octreotide. RESULTS: Cases 1 and 2 were both middle-aged women. They presented thyrotoxicosis with a low serum concentration of TSH and thyroidal radioactive iodine uptake (RAIU). The underlying causes, such as thyroiditis, metastatic thyroid cancer and struma ovarii were explored. Iodine-induced hyperthyroidism, particularly factitious hyperthyroidism was highly suspected, but there was no direct evidence to establish these diagnoses. In spite of good compliance, their thyrotoxicosis could not be controlled with large doses of PTU or MMI. ß-blocker, methylprednisolone, radio-iodine therapy and even thyroidectomy were all attempted and failed. Short-acting octreotide was first administered to case 1 and then to case 2. Thyroid function improved greatly within 3 days in both cases. The doses of octreotide were tapered down to twice a week with consistent efficacy. During the follow-up periods, case 1 required octreotide 0.1mg twice per week and case 2 is on thyroid replacement therapy due to hypothyroidism. The recurrences of hyperthyroidism in both cases were again rapidly controlled with the increased dose of octreotide in case 1 and re-started the usage of octreotide in case 2. CONCLUSIONS: The etiology of thyrotoxicosis in these 2 cases is not clear. In the absence of struma ovarii or wide-spread follicular thyroid cancer, factitious hyperthyroidism due to Munchausen syndrome should be considered first. The efficacy of the off-label use of octreotide in hyperthyroidism was highly effective (only) in these 2 cases.

Association of the CTLA4 gene with Graves' disease in the Chinese Han population.

To determine whether genetic heterogeneity exists in patients with Graves' disease (GD), the cytotoxic T-lymphocyte associated 4 (CTLA-4) gene, which is implicated a susceptibility gene for GD by considerable genetic and immunological evidence, was used for association analysis in a Chinese Han cohort recruited from various geographic regions. Our association study for the SNPs in the CTLA4 gene in 2640 GD patients and 2204 control subjects confirmed that CTLA4 is the susceptibility gene for GD in the Chinese Han population. Moreover, the logistic regression analysis in the combined Chinese Han cohort revealed that SNP rs231779 (allele frequencies p = 2.81x10(-9), OR = 1.35, and genotype distributions p = 2.75x10(-9), OR = 1.42) is likely the susceptibility variant for GD. Interestingly, the logistic regression analysis revealed that SNP rs35219727 may be the susceptibility variant to GD in the Shandong population; however, SNP, rs231779 in the CTLA4 gene probably independently confers GD susceptibility in the Xuzhou and southern China populations. These data suggest that the susceptibility variants of the CTLA4 gene varied between the different geographic populations with GD.

Identification of steroid biosynthetic defects in genotype-proven heterozygous individuals for 17alpha-hydroxylase/17,20-lyase deficiency.

OBJECTIVE: P450c17 deficiency (17alpha-hydroxylase/17,20-lyase deficiency, 17OHD) is a rare form of congenital adrenal hyperplasia caused by CYP17A1 gene mutations. The D487_F489 deletion in exon 8 and Y329fs in exon 6 are relatively frequent mutations of the CYP17A1 gene in China that completely abolish the enzyme activity of P450c17. However, little remains known about steroid biosynthetic functions in carriers with these mutations in a single allele of the CYP17A1 gene, who are assumed to have 50% P450c17 activity. We investigated adrenal steroidogenic function in genotype-proven heterozygotes carrying such mutations in the CYP17A1 gene in vivo. PATIENTS AND DESIGN: Eight patients and fourteen family members from five families with 17OHD were recruited. The mutations of the CYP17A1 gene in these individuals were screened by sequencing. The hormonal response to cosyntropin (ACTH) was evaluated in the 14 genotype-proven carriers and 45 age- and gender-matched normal controls. RESULTS: Fourteen carriers of the CYP17A1 mutation - seven with the D487_F489 deletion, six with Y329fs and one with H373L - were identified from the five families with 17OHD. Compared with normal controls, carriers showed lower basal and ACTH-stimulated cortisol levels but higher ACTH-stimulated corticosterone levels. The ratios of corticosterone to cortisol in the genotype-proven heterozygotes were higher than those of the normal controls at the baseline and after cosyntropin stimulation. Similarly, the progesterone levels and the ratios of progesterone to 17-hydroxyprogesterone in the male heterozygotes were also higher than those of the normal controls, both before and after ACTH stimulation. CONCLUSION: Genotype-proven carriers of the CYP17A1 mutation who lack apparent clinical symptoms exhibit decreased adrenal 17alpha-hydroxylase activity and altered adrenal gland reserve for steroid biosynthesis.

A splice site mutation combined with a novel missense mutation of LHCGR cause male pseudohermaphroditism.

Leydig cell hypoplasia (LCH) is a rare form of male pseudohermaphroditism caused by inactivating mutations in the luteinizing hormone receptor gene (LHCGR). The majority of LHCGR mutations are located in the coding sequence, resulting in impairment of either LH/CG binding or signal transduction. We report a Chinese family with two siblings (46, XY and 46, XX) carrying a missense mutation (c. 455 T>C, p. Ile152Thr) and a splice site mutation (c. 537-3 C>A). Computational analysis of the missense mutation in the three-dimensional structural model predicted it might influence the distribution of hydrogen bonds and intermolecular contacts between the hormone and receptor. Consistent with these findings, in vitro mutant analysis revealed a marked impairment of human chorionic gonadotropin binding and signal transduction. The splice-acceptor mutation (c. 537-3 C>A) resulted in abnormal splicing of LHCGR mRNA, skipping exon 7. This report expands the genotypic spectrum of LHCGR mutations, with relevant implications for the molecular analysis of this gene.

Efficacy and safety of 2 g/day of strontium ranelate in Asian women with postmenopausal osteoporosis.

Strontium ranelate is a new effective anti-osteoporotic treatment having a unique mode of action, reducing bone resorption while promoting continued bone formation, with a broad range of anti-fracture efficacy at vertebral as well as peripheral sites. In Phase III studies, it has proven its early and sustained efficacy against vertebral fractures in Caucasians along with a significant increase in lumbar bone mineral density (BMD). The aim of this randomized double-blind study was to demonstrate the efficacy of strontium ranelate (2 g/day) on lumbar spine bone mineral density and the clinical and biological safety in Asian postmenopausal osteoporotic patients compared to placebo over 1 year. Three hundred and twenty-nine eligible women from mainland China, Hong Kong and Malaysia were randomized into the study. The baseline characteristics were similar in the treatment and placebo groups: mean age of 66.2+/-6.5 years, time since menopause 17.6+/-7.2 years. In the Full Analysis Set (FAS, N=302), the mean baseline lumbar L2-L4 BMD was 0.715+/-0.106 g/cm(2) in the strontium ranelate group and 0.708 +/- 0.109 g/cm2 in the placebo group. The mean baseline femoral neck BMD was 0.575+/-0.074 g/cm2 and 0.566+/-0.069 g/cm2 respectively and mean total hip BMD was 0.642+/-0.080 g/cm2 and 0.631 +/-0.088 g/cm2 respectively. The overall compliance was 91.4% in the study drug group, and 97.4% in the placebo group. After 1 year of treatment, the lumbar spine, femoral neck and total hip BMD in the treated group was significantly increased by 3-5% as compared to placebo. Strontium ranelate was well tolerated. The most frequently reported emergent adverse events were comparable in both groups (60.4% versus 60.0%), with majority of them being mild gastrointestinal disorders. There were no clinically relevant changes in laboratory tests, such as blood routine, hepatic and renal function. It is thus concluded that the effects of 2 g/day strontium ranelate on BMD and its safety profile in this cohort of postmenopausal osteoporotic Asian women were consistent with results obtained from Caucasian women in which the efficacy on the reduction in risk of fracture has been proven.

Functional SNPs in the SCGB3A2 promoter are associated with susceptibility to Graves' disease.

Graves' disease (GD) is one of the most common human autoimmune diseases, and recent data estimated a prevalence of clinical hyperthyroidism of 0.25-1.09% in the population. Several reports have linked GD to the region 5q12-q33; and a locus between markers D5s436 and D5s434 was specifically linked to GD susceptibility in the Chinese population. In the present study, association analysis was performed using a large number of single-nucleotide polymorphisms (SNPs) at this locus in 2811 patients with GD recruited from different geographic regions of China. The strongest associations with GD in the combined Chinese Han cohorts were mapped to two SNPs in the promoter (pSNP) of SCGB3A2 [SNP76, rs1368408, P = 1.43 x 10(-6), odds ratio (OR) = 1.28 and SNP75, -623 - -622, P = 7.62 x 10(-5), OR = 1.32, respectively], a gene implicated in immune regulation. On the other hand, pSNP haplotypes composed of the SNP76 (rs1368408)+SNP74 (rs6882292) or SNP76+SNP75 (-623 approximately -622, AG/T) variants are correlated with high disease susceptibility (P = 0.0007, and P = 0.0192, respectively) in this combined Chinese Han cohort. Furthermore, these haplotypes were associated with reduced SCGB3A2 gene expression levels in human thyroid tissue, while functional analysis revealed a relatively low efficiency of SCGB3A2 promoters of the SNP76+SNP75 and SNP76+SNP74 haplotypes in driving gene expression. These results suggest that the SCGB3A2 gene may contribute to GD susceptibility.

IGF-1 as an early marker for low bone mass or osteoporosis in premenopausal and postmenopausal women.

To find out which of the following parameters-serum levels of insulin-like growth factor 1 (IGF-1), osteoprotegerin (OPG), leptin, osteocalcin (OC), and urinary excretion of N-terminal telopeptide of type I collagen (NTx), can be used as an early marker for osteopenia/osteoporosis in women diagnosed by dual-energy X-ray absorptiometry (DXA), 282 premenopausal and 222 postmenopausal women aged 20-75 years were investigated by the measurement of bone mineral densities (BMDs) at lumbar spine (LS) and femoral neck (FN) by DXA, together with serum concentrations of IGF-1, OPG, leptin, OC, and urinary NTx. The characteristics of the earliest marker(s) were tested with the receiver operating characteristic (ROC) analysis. The area under the curve (AUC), sensitivity, and specificity parameters were determined. It was revealed that serum levels of IGF-1 and leptin changed the earliest, with both markers significantly decreasing (P < 0.0001) or increasing (P = 0.020), respectively, at age 30. However, in ROC analysis, IGF-1 was the only early parameter that had the capacity to differentiate the low bone mass/osteoporosis women from the normal ones (P < 0.0001). If the serum level of IGF-1 at 1.5 SD below its peak was adopted as a cutoff point, it could identify women with low bone mass/osteoporosis with a sensitivity of 73% and specificity of 67%. In the premenopausal women subgroup analysis, the low bone mass women (30/282, 10.6%) were older (38.2 +/- 1.7 vs. 34.5 +/- 0.5 years; P = 0.026), with lower serum levels of IGF-1 (215.1 +/- 22.4 vs. 278.8 +/- 9.4 ng/ml; P = 0.02) and less lean mass (33.1 +/- 0.6 vs. 34.8 +/- 0.2 kg; P = 0.010) than the normal ones. After controlling for age, the serum level of IGF-1 had a weak, but still significant, positive correlation with lean mass (r = 0.17, P < 0.001). In conclusion, measurement of serum IGF-1 in young women may help in the early identification of those at risk for developing low bone mass and osteoporosis.

Interleukin-18 enhances glucose uptake in 3T3-L1 adipocytes.

In order to characterize the potential causative effects of interleukin-18 (IL-18) on insulin resistance, we measured glucose uptake in 3T3-L1 adipocytes treated with mouse recombinant IL-18. IL-18 surprisingly enhanced, rather than reduced insulin-mediated glucose uptake in adipocytes. Moreover IL-18 could counteract the glucose uptake suppression caused by tumor necrosis factor alpha in 3T3-L1 adipocytes. The mechanism dissection showed that the IL-18 upregulated phosphorylated Akt and downregulated phosphorylated P38 MAPK. These findings indicated that the elevated serum IL-18 levels in obesity and diabetes might be a compensatory response to insulin resistance.

Effect of short-term and long-term fasting on transcriptional regulation of metabolic genes in rat tissues.

Ninety-eight genes/ESTs with differential expressions in epididymal adipose tissue of fed and 3-day fasting (F3) rats were identified by microarray analysis. Genes for lipogenesis, glycolysis, and glucose aerobic oxidation were decreased in response to starvation. Further study was performed to investigate the expression patterns of these genes in rat tissues after short- and long-term starvations. The results of the increased expression of the pyruvate dehydrogenase kinase 4 (PDK4) gene and decreased pyruvate dehydrogenase (PDH) in rat muscle together with decreased fatty acid synthase (FAS) in rat adipose tissue after 1 day of fasting (F1) suggested from transcriptional level that glucose aerobic oxidation was down-regulated in rat muscle and synthesis of saturated fatty acids was inhibited in rat adipose tissue after short-term fasting. It was noted that the transcriptions of genes involved in the fatty acid oxidation, such as very-long-chain Acyl-CoA dehydrogenase (LCAH), Acyl-CoA oxidase (ACO), carnitine palmitoyltransferase-I (CPT-I), and carnitine-acylcarnitine translocase (CAT)L, were greatly increased in F1 rat liver, then began to decrease in F3 and 5-day fasting (F5) rat liver, combined with significantly increased serum non-esterified fatty acids (NEFA) in F1 rats and increased urea in F5 rats, suggesting that inhibition of the oxidation of lipid and not the decreased availability of these fuels may play an important role in the phase II-phase III of fasting transition in the long-term fasting rats.

The mimecan gene expressed in human pituitary and regulated by pituitary transcription factor-1 as a marker for diagnosing pituitary tumors.

CONTEXT: Mimecan, a secretory protein, belongs to a family of small leucine-rich proteoglycans (SLRPs). The physiological functions of mimecan have not been fully understood. OBJECTIVE: We hypothesize that the mimecan gene expressed in the human pituitary and regulated by pituitary transcription factor-1 (Pit-1) might act as a marker for diagnosing pituitary tumors. DESIGN: The clinical aspect of our work was a cross-sectional study. SETTING AND PATIENTS: In total, 20 pituitary tumor samples were collected from January 1, 2002, to December 30, 2002, in Ruijin Hospital, Shanghai, China. INTERVENTION: The number of pituitary tumors was limited. Collection of more pituitary tumor samples for additional observation will be necessary. MAIN OUTCOME MEASURES: The main outcomes were measured by Northern blot, in situ hybridization, immunohistochemical analysis, and so on. RESULTS: The mimecan gene was expressed at a moderate level in the mouse pituitary gland by Northern blot analysis. Expression of mimecan mRNA and protein is also observed in the human anterior pituitary gland. Luciferase reporter analysis and electrophoretic mobility shift assays show that Pit-1 activates the human mimecan promoter through Pit-1 response element sites. In addition, our data also show that almost all the ACTH- or GH-positive pituitary tumors likely express mimecan protein, and only a portion of prolactin-, TSH-, FSH-, and LH-positive pituitary tumors express mimecan protein. CONCLUSIONS: This work provides insight into the regulating mechanism of mimecan in pituitary and suggests that mimecan may be an unidentified pituitary secretory protein, and certain pituitary cells secreting ACTH or GH also secrete mimecan.

Structure and functional analysis of unclassified genes strongly expressed in human visceral adipose tissue.

Our previous work has described the gene expression patterns of human visceral adipose tissue (VAT) at the transcriptome level and reported that the strongly expressed genes in VAT showed an uneven distribution throughout the genome. The aim of the present work was to focus on the unclassified genes and known expressed sequence tags (ESTs) strongly expressed in VAT and analyze their structure and function with bioinformatics. Among the 400 ESTs strongly expressed in the VAT, 340 clones were classified into known genes through searching the latest Genbank database. Functional classification showed that 85 clones were unclassified known genes, and approx 90% of them were found to be expressed in adipose tissue for the first time. Among the 85 unclassified genes, only two share similarities in the coding sequences with all species examined, and six genes had so far no obvious similarity to any genes across different species. The protein products of 7 genes had putative signal peptide and 11 had transmembrane domains. The protein products of 39 genes had relative specific motifs or prosites on primary structure. In silico Northern blot showed that 21 known ESTs were abundantly specifically expressed in adipose tissue, which may provide clues to identify novel genes closely related to adipocyte function with potential pathophysiological implications.

The influence of Lys3Asn polymorphism in the osteoprotegerin gene on bone mineral density in Chinese postmenopausal women.

The objective was to identify single nucleotide polymorphisms (SNPs) in exons of the osteoprotegerin gene and to analyze the relationship between the SNPs and bone mineral density in postmenopausal women. We used polymerase chain reaction (PCR) and direct sequencing methods to identify SNPs and genotypes in 205 postmenopausal women. BMD at the lumbar spine (L2-4) and femoral neck (FN) were measured by dual-energy X-ray absorptiometry (DEXA). Serum osteocalcin (OC), osteoprotegerin (OPG), receptor activator of nuclear factor kappaB ligand (RANKL) and urinary N-telopeptide of type I collagen (NTx) were also measured. In exon 1 of the OPG gene, we found the Lys3Asn SNP. In 205 postmenopausal women, the Asn-allele frequency was 26.0%, and the distribution of Lys3Asn genotypes was Lys-Lys 56.6%, Lys-Asn 34.6% and Asn-Asn 8.8%, respectively. BMD at the lumbar spine (L2-4) of the Asn-Asn genotype was significantly higher (9.5-12.6%) than Lys-Asn and Lys-Lys genotypes (P=0.012), with evidence for an allele dose effect (P=0.008). Results remained similar after adjustment for age and body mass index. The Lys3Asn polymorphism of the OPG gene alone accounted for 7.7% of the variance of the L2-4 BMD in a multiple regression model. Logistic regression analysis revealed that the OPG genotype Lys-Lys had a 2.7 times (95% CI: 0.83-9.11) greater risk for osteopenia/osteoporosis than the Asn-Asn genotype. The Lys3Asn polymorphism in the OPG gene is associated with L2-4 BMD in postmenopausal women. The Lys-allele is associated with lower BMD and an increased risk for osteoporosis.