Body fat distribution and their associations with cardiovascular risk, insulin resistance and β-cell function: are there differences between men and women?

OBJECTIVE

The objective was to examine the independent and gender-specific effects of WC and BMI on CVD risk factors, insulin resistance and β-cell function.

DESIGN

A cross-sectional study of 2931 adults aged 20-79 years was carried out in Fujian province by multi-stratified sampling from July 2007 to May 2008. Gender-specific differences of WC and BMI on CVD risk factors, insulin resistance and β-cell function were displayed jointly by WC and BMI tertiles. The homeostasis model assessment of insulin resistance (HOMA-IR) index and the quantitative insulin-sensitivity check index (QUICKI): l/(log G0 ± log I0) were used to estimate insulin sensitivity; insulin secretion was assessed using the HOMA-β index; β-cell function was quantified as the ratio of the incremental insulin to glucose responses over the first 30 min during the OGTT (△I30/△G30). The oral disposition index (DIo) was calculated as ΔI(30) /ΔG(30) × 1/fasting insulin. The Matsuda index is defined as 10,000/sqrt (FBG × FPI × [G × I]) where FPG is fasting glucose, FPI is fasting insulin, G is mean glucose during the OGTT (calculated from glucose samples at 0, 30, and 120 min), and I is mean insulin during the OGTT (calculated from insulin samples at 0, 30, and 120 min).

RESULTS

Waist circumference and BMI correlated with each other in both men (0.756, p < 0.001) and women (0.728, p < 0.001). The two indexes were independently associated with CVD risk factors (such as hypertension, metabolic syndrome, and dyslipidaemia) in both men and women. BMI was better than WC in assessing the risk of diabetes in men (p = 0.003 for BMI, and p = 0.234 for WC), while WC was better than BMI in predicting diabetes in women (p < 0.001 for WC, and p = 0.831 for BMI). There were significant associations between BMI and insulin resistance or β-cell function even after adjustment for WC except for DIo in male subjects, but WC only associated with HOMA-IR positively or the Matsuda index and QUICKI negatively after adjustment for BMI. For women, associations between WC and insulin resistance or β-cell function remained strong even after adjustment for BMI besides DIo. However, there were no independent relations of BMI to insulin resistance and β-cell function except for Matsuda index with a significant negative association after adjustment for WC in women.

CONCLUSION

Body mass index and WC were independently associated with CVD risk factors. There were differences in the gender-specific relevance of measures of body fat distribution in assessing the insulin resistance, β-cell function and thus the risk of diabetes. Therefore, WC should be measured in addition to BMI to assess CVD risk accurately and implement efficient treatment strategies.

Therapeutic induction of tolerance by IL-10-differentiated dendritic cells in a mouse model of house dust mite-asthma

BACKGROUND

It has been reported that retrovirally transduced IL-10-expressing dendritic cells can reverse the asthma phenotype in mice, but that i.v. delivery of dendritic cells differentiated with IL-10 alone (DC10) does not. We report herein DC10 can be highly effective therapeutically in experimental asthma.

METHODS

BALB/c mice were sensitized by airway exposure to house dust mite (HDM) without use of adjuvants, then treated with 10⁶ allergen-presenting DC10. We assessed the airway hyperresponsiveness (AHR) to methacholine, circulating levels of IgE and IgG1, and airway recall responses to HDM allergen, including eosinophilia and Th2 cytokines. We also asked whether the DC10 treatments induced tolerance through activation of pulmonary regulatory T cell activities.

RESULTS

In vitro, cognate-, but not irrelevant-, allergen-presenting DC10 productively engaged pulmonary Th2-phenotype CD4(+) cells magnetically sorted from HDM-asthmatic mice in Forster (or fluorescence) resonance energy transfer assays. In vivo, treatment of HDM-asthmatic mice with HDM, but not ovalbumin-presenting DC10 abrogated AHR within 4 weeks, and significantly reduced airway eosinophilia, IL-4, IL-5, and IL-13 responses, and circulating HDM-specific IgE and IgG1 levels (each, P ≤ 0.01 versus control mice). CD4(+) CD25(+) Foxp3(+) cells from the lungs of the DC10-treated mice, but not those from asthmatic animals, up-regulated expression of the activated regulatory T cell markers CTLA4 and LAG3, and passive transfer of pulmonary CD4(+) T cells from these mice induced allergen tolerance in HDM-asthmatic recipients.

CONCLUSIONS

These findings indicate that allergen-presenting DC10 treatments up-regulate T cell regulatory activities and thereby induce allergen-specific tolerance in a relevant model of human asthma.

The correlation between the oral glucose tolerance test 30-minutes plasma glucose and risk factors for diabetes and cardiovascular diseases: a cross-sectional epidemiological study of diabetes in Fujian Province in the South-East of China

OBJECTIVE

To investigate the correlation between abnormal oral glucose tolerance test (OGTT) 30-min plasma glucose (PG) and risk factors and metabolic abnormalities of diabetes and cardiovascular diseases (CVD).

METHODS

Participants (no.=2457) underwent a physical examination, blood biochemistry examination, OGTT, and a 12-lead electrocardiogram. We measured fasting PG (FPG) and PG at 30 min (30minPG) and 1 h (1hPG) of the OGTT. The association between an increase in 30minPG (by 1 SD) and the metabolic abnormalities of diabetes and CVD such as hypertension, overweight and obesity, central obesity, and hyperlipidemia; osteoporosis was assessed by logistic regression analysis after controlling for FPG and 2hPG.

RESULTS

This analysis showed that an increase of 30minPG by 1 SD (1.92 mmol/l) significantly increased the risk of chronic metabolic abnormalities in diabetes and CVD such as hypertension, overweight, and obesity, central obesity, hyperlipidemia, and osteoporosis. Stepwise multiple regression analysis also showed that 30minPG was significantly correlated with male gender, smoking, FPG, 2hPG, total cholesterol, waist/hip ratio, and blood pressure.

CONCLUSIONS

An elevation of 30minPG increased the risk of diabetes and CVD. The increased risk was independent of FPG, 2hPG, age, sex, and smoking status.

FOXO1 inhibits Runx2 transcriptional activity and prostate cancer cell migration and invasion

Prostate cancer patients with regional lymph node involvement at radical prostatectomy often experience disease progression to other organs, with the bone as the predominant site. The transcription factor Runx2 plays an important role in bone formation and prostate cancer cell migration, invasion, and metastasis. Here we showed that the forkhead box O (FOXO1) protein, a key downstream effector of the tumor suppressor PTEN, inhibits the transcriptional activity of Runx2 in prostate cancer cells. This inhibition was enhanced by PTEN but diminished by active Akt. FOXO1 bound to Runx2 in vitro and in vivo and suppressed Runx2's activity independent of its transcriptional function. FOXO1 inhibited Runx2-promoted migration of prostate cancer cells, whereas silencing of endogenous FOXO1 enhanced prostate cancer cell migration in a Runx2-dependent manner. Forced expression of FOXO1 also inhibited Runx2-promoted prostate cancer cell invasion. Finally, we found that expression of PTEN and the level of FOXO1 in the nucleus is inversely correlated with expression of Runx2 in a cohort of prostate cancer specimens from patients with lymph node and bone metastasis. These data reveal FOXO1 as a critical negative regulator of Runx2 in prostate cancer cells. Inactivation of FOXO1 due to frequent loss of PTEN in prostate cancer cells may leave the oncogenic activities of Runx2 unchecked, thereby driving promiscuous expression of Runx2 target genes involved in cell migration and invasion and favoring prostate cancer progression.

Purging efficacy of ZnPcH₁-based photodynamic therapy on chronic myeloid leukemia bone marrow

INTRODUCTION

Ex vivo purging is an emerging technique for successful transplantation of autologous hematopoietic stem cells in the treatment of leukemia. Among them, photodynamic therapy (PDT) might be a promising modality. The objective of this study was to evaluate the purging efficacy of ex vivo PDT on chronic myeloid leukemia (CML).

METHODS

A new amphiphilic mono-α-substituted zinc (II) phthalocyanine (ZnPcH₁) was used as a PDT photosensitizer. Nest reverse transcription polymerase chain reaction (RT-PCR) and real-time quantitative PCR of BCR/ABL1 fusion gene remained positive were performed to determine the purging effects of ZnPcH₁-PDT on the mixture of CML cell line K562 cells and normal bone marrow mononuclear cells (MNC) and on the CML cells from the bone marrow of patients with CML who had achieved complete hematology remission but whose BCR/ABL1 fusion genes remained positive.

RESULTS

CML cells exhibited higher susceptibility to ZnPcH₁-PDT than normal granulocyte/macrophage progenitors. PDT could eliminate K562 cells from K562-normal MNC mixture and the residual BCR/ABL1 positive CML cells from the bone marrow of patients with CML.

CONCLUSION

Our data suggest that ZnPcH₁-PDT may be a useful modality for purging CML cells for autologous grafts.

Replication of genome-wide association studies (GWAS) loci for fasting plasma glucose in African-Americans

AIMS/HYPOTHESIS

Chronically elevated blood glucose (hyperglycaemia) is the primary indicator of type 2 diabetes, which has a prevalence that varies considerably by ethnicity in the USA, with African-Americans disproportionately affected. Genome-wide association studies (GWASs) have significantly enhanced our understanding of the genetic basis of diabetes and related traits, including fasting plasma glucose (FPG). However, the majority of GWASs have been conducted in populations of European ancestry. Thus, it is important to conduct replication analyses in populations with non-European ancestry to identify shared loci associated with FPG across populations.

METHODS

We used data collected from non-diabetic unrelated African-American individuals (n = 927) who participated in the Howard University Family Study to attempt to replicate previously published GWASs of FPG. Of the 29 single nucleotide polymorphisms (SNPs) previously reported, we directly tested 20 in this study. In addition to the direct test, we queried a 500 kb window centred on all 29 reported SNPs for local replication of additional markers in linkage disequilibrium (LD).

RESULTS

Using direct SNP and LD-based comparisons, we replicated multiple SNPs previously associated with FPG and strongly associated with type 2 diabetes in populations with European ancestry. The replicated SNPs included those in or near TCF7L2, SLC30A8, G6PC2, MTNR1B, DGKB-TMEM195 and GCKR. We also replicated additional variants in LD with the reported SNPs in ZMAT4 and adjacent to IRS1.

CONCLUSIONS/INTERPRETATION

We identified multiple GWAS variants for FPG in our cohort of African-Americans. Using an LD-based strategy we also identified SNPs not previously reported, demonstrating the utility of using diverse populations for replication analysis.

Validation of the AJCC staging system (7th edition) in Asian patients with localized prostate cancer undergoing radical radiotherapy

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Background: The epidemiology of prostate cancer (PCa) varies widely internationally. Although prostate cancer is usually regarded as uncommon in Asia, dramatic rises in recent years have resulted in it being ranking third by incidence in Singapore. Conventional prognostic parameters derived from Western populations have been integrated into systems such as the new AJCC seventh edition staging system, the validity of which is unclear in Asia. We thus sought to validate its performance, alongside other prognostic factors in a large Asian series of radiotherapy patients.

Methods: A retrospective review of 404 consecutive Singaporean patients receiving radical radiotherapy between 1997 and 2005 at the National Cancer Centre was performed. The primary outcome was biochemical relapse free survival (BRFS), defined by the Phoenix criteria. Prognostic risk groups were defined using AJCC seventh edition. Univariate analysis (UVA) and multivariate analysis (MVA) was performed for other putative risk factors: age, race, Gleason score, prognostic risk grouping, tumour classification, radiation delivery technique, radiotherapy dose, hormonal therapy (HT) and initial PSA.

Results: Median age was 69; median BRFS was 55 months with 71 biochemical relapses. 4 risk factors showed univariate association with BRFS: AJCC risk groups (p=0.038), T-stage (p=0.018), RT dose (p=0.025) and initial PSA value (p=0.013) with AJCC risk groups and initial PSA value remaining significant after MVA ( Table ). Harrell's c-index for AJCC risk grouping was 0.56, with no significant difference seen in outcomes between AJCC risk group II and III.

Conclusions: Our results validate the new AJCC seventh edition prostate cancer prognostic risk grouping in an Asian radiotherapy population for the first time; the actual association however is relatively weak possibly due to differences in biology, screening or epidemiology.

[Table: see text]

No significant financial relationships to disclose.

Fine-scale spatial genetic structure and gene flow in a small, fragmented population of Sinojackia rehderiana (Styracaceae), an endangered tree species endemic to China

Populations of Sinojackia rehderiana are highly threatened and have small and scattered distribution due to habitat fragmentation and human activities. Understanding changes in genetic diversity, the fine-scale spatial genetic structure (SGS) at different life stages and gene flow of S. rehderiana is critical for developing successful conservation strategies for fragmented populations of this endangered species. In this study, 208 adults, 114 juveniles and 136 seedlings in a 50 × 100-m transect within an old-growth forest were mapped and genotyped using eight microsatellite makers to investigate the genetic diversity and SGS of this species. No significant differences in genetic diversity among different life-history stages were found. However, a significant heterozygote deficiency in adults and seedlings may result from substantial biparental inbreeding. Significant fine-scale spatial structure was found in different life-history stages within 19 m, suggesting that seed dispersal mainly occurred near a mother tree. Both historical and contemporary estimates of gene flow (13.06 and 16.77 m) indicated short-distance gene dispersal in isolated populations of S. rehderiana. The consistent spatial structure revealed in different life stages is most likely the result of limited gene flow. Our results have important implications for conservation of extant populations of S. rehderiana. Measures for promoting pollen flow should be taken for in situ conservation. The presence of a SGS in fragmented populations implies that seeds for ex situ conservation should be collected from trees at least 19-m apart to reduce genetic similarity between neighbouring individuals.

Adhesion Strength of Cu/Polyimide Interfaces by Micro-Wedge Scratching

The micro-wedge scratch technique was applied to characterize interfacial properties of copper fine lines on PMDA-ODA polyimide. A 20 pm wide, 0.1 μm radius wedge-shapeddiamond tip was used to mechanically debond Cu fine lines from polyimide substrate. Copper fine lines varies from 0.2 to 0.4 μm thick, and from 1.μm to 100 μm wide. Both cohesive and adhesive delaminations were obtained. Loaddisplacement curves were recorded and the scratch morphologies were observed by SEM. From a first order calculation, the fracture toughness of the polyimide and interfacial strength of Cu-PI were obtained.

Phosphorylation of EZH2 by CDK1 and CDK2: a possible regulatory mechanism of transmission of the H3K27me3 epigenetic mark through cell divisions

Histone H3 lysine 27 trimethylation (H3K27me3) catalyzed by the enzymatic subunit EZH2 in the Polycomb repressive complex 2 (PRC2) is essential for cells to 'memorize' gene expression patterns through cell divisions and plays an important role in establishing and maintaining cell identity during development. However, how the epigenetic mark is inherited through cell generations remains poorly understood. Recently, we and others demonstrate that CDK1 and CDK2 phosphorylate EZH2 at threonine 350 (T350) and that T350 phosphorylation is important for the binding of EZH2 to PRC2 recruiters, such as noncoding RNAs (ncRNAs) HOTAIR and XIST, and for the effective recruitment of PRC2 to EZH2 target loci in cells. These findings imply that phosphorylation of EZH2 by CDK1 and CDK2 may provide cells a mechanism that enhances EZH2 function during S and G2 phases of the cell cycle, thereby ensuring K27me3 on de novo synthesized H3 incorporated in nascent nucleosomes before sister chromosomes are divided into two daughter cells. Additionally, a potential role of T350 phosphorylation of EZH2 in differing EZH2 from its homolog EZH1 in catalyzing H3K27me3 as well as the interplay between phosphorylation at T350 and other residues (e.g. phosphorylation by p38 at threonine 372 (T372)) in governing EZH2 activity in proliferating versus non-dividing cells are also discussed. Together, CDK phosphorylation of EZH2 at T350 may represent a key regulatory mechanism of EZH2 function that is essential for the maintenance of H3K27me3 marks through cell divisions.

Phosphorylation of EZH2 by CDK1 and CDK2: a possible regulatory mechanism of transmission of the H3K27me3 epigenetic mark through cell divisions

Histone H3 lysine 27 trimethylation (H3K27me3) catalyzed by the enzymatic subunit EZH2 in the Polycomb repressive complex 2 (PRC2) is essential for cells to 'memorize' gene expression patterns through cell divisions and plays an important role in establishing and maintaining cell identity during development. However, how the epigenetic mark is inherited through cell generations remains poorly understood. Recently, we and others demonstrate that CDK1 and CDK2 phosphorylate EZH2 at threonine 350 (T350) and that T350 phosphorylation is important for the binding of EZH2 to PRC2 recruiters, such as noncoding RNAs (ncRNAs) HOTAIR and XIST, and for the effective recruitment of PRC2 to EZH2 target loci in cells. These findings imply that phosphorylation of EZH2 by CDK1 and CDK2 may provide cells a mechanism that enhances EZH2 function during S and G2 phases of the cell cycle, thereby ensuring K27me3 on de novo synthesized H3 incorporated in nascent nucleosomes before sister chromosomes are divided into two daughter cells. Additionally, a potential role of T350 phosphorylation of EZH2 in differing EZH2 from its homolog EZH1 in catalyzing H3K27me3 as well as the interplay between phosphorylation at T350 and other residues (e.g. phosphorylation by p38 at threonine 372 (T372)) in governing EZH2 activity in proliferating versus non-dividing cells are also discussed. Together, CDK phosphorylation of EZH2 at T350 may represent a key regulatory mechanism of EZH2 function that is essential for the maintenance of H3K27me3 marks through cell divisions.