Predictive value of ankle-brachial index and blood glucose on the outcomes of six-year all-cause mortality and cardiovascular mortality in a Chinese population of type 2 diabetes patients

AIM

The aim of this paper was to investigate the predictive value of ankle-brachial index (ABI) and blood glucose to estimate mortality in Chinese type 2 diabetes patients.

METHODS

Chinese type 2 diabetes patients (1706 subjects) were followed up for about 6 years,

RESULTS

One thousand four hundred fourteen were included in the final statistical analysis during a median follow-up of 69 months. Overall, 398 patients died during follow-up and 254 deaths were attributable to cardiovascular disease (CVD). Relative risks of all-cause and CVD mortality of patients with ABI≤0.4 were increased by 2.073-fold (95% CI: 1.236-3.478) and 3.086-fold (95% CI: 1.702-5.595), compared with those of patients with ABI>1.0 and ≤1.4. Mortality was significantly increased with increasing plasma glucose and decreasing ABI. All-cause and CVD mortality was the highest (55.6% and 44.4%) with ABI≤0.4 and plasma glucose >10 mmol/L simultaneously. Relative risks of all-cause and CVD mortality in these patients were increased by 3.905-fold (95% CI: 1.334-11.431) and 3.771-fold (95% CI: 1.079-13.171), compared with patients with ABI>1.0 and ≤1.4, and plasma glucose ≤6 mmol/L simultaneously. Models to evaluate additional predictive value of ABI for mortality of type 2 diabetes patients suggested that addition of ABI significantly improved the prediction of the death rate compared with the model including conventional risk factors only.

CONCLUSION

High plasma glucose and low ABI had synergistic effects on increasing mortality of type 2 diabetes patients. The addition of ABI can significantly improve the prediction of mortality compared to protocol using conventional risk factors only.

Identification of differentially expressed genes and pathways between primary osteoarthritis and endemic osteoarthritis (Kashin-Beck disease)

OBJECTIVES

Primary osteoarthritis (OA) and Kashin-Beck disease (KBD) exhibit similar clinical manifestations and common articular cartilage lesions. Revealing the pathogenetic differences between OA and KBD is helpful for differential diagnosis and may provide new insights into the pathogenesis of OA and KBD. In this study, we compared the genome-wide gene ontology (GO) and pathway expression patterns of articular cartilage derived from both OA and KBD patients.

METHODS

Total RNA was isolated, amplified, labelled, and hybridized using Agilent whole genome microarray analysis. Gene set enrichment analysis (GSEA) was used to identify differentially expressed genes and pathways between OA and KBD. Nine differentially expressed GO categories and 85 differentially expressed pathways were identified by this study.

RESULTS

The reactive oxygen species (ROS)-related HOUSTIS_ROS pathway and the vascular endothelial growth factor (VEGF)-related ABE_VEGFA_TARGETS_2HR pathway were significantly up-regulated in OA compared to KBD. Higher expression levels of the collagen-related COLLAGEN GO, EXTRACELLULAR_MATRIX_PART GO, and nitric oxide (NO)-related BIOCARTA_NO1_PATHWAY pathways were detected in KBD than in OA.

CONCLUSIONS

ROS-induced cartilage lesions seem to be more involved in the pathogenesis of OA whereas NO-mediated chondrocyte apoptosis contributes more to the development of KBD.

Transferability and fine-mapping of glucose and insulin quantitative trait loci across populations: CARe, the Candidate Gene Association Resource

AIMS/HYPOTHESIS

Hyperglycaemia disproportionately affects African-Americans (AfAs). We tested the transferability of 18 single-nucleotide polymorphisms (SNPs) associated with glycaemic traits identified in European ancestry (EuA) populations in 5,984 non-diabetic AfAs.

METHODS

We meta-analysed SNP associations with fasting glucose (FG) or insulin (FI) in AfAs from five cohorts in the Candidate Gene Association Resource. We: (1) calculated allele frequency differences, variations in linkage disequilibrium (LD), fixation indices (F(st)s) and integrated haplotype scores (iHSs); (2) tested EuA SNPs in AfAs; and (3) interrogated within ± 250 kb around each EuA SNP in AfAs.

RESULTS

Allele frequency differences ranged from 0.6% to 54%. F(st) exceeded 0.15 at 6/16 loci, indicating modest population differentiation. All iHSs were <2, suggesting no recent positive selection. For 18 SNPs, all directions of effect were the same and 95% CIs of association overlapped when comparing EuA with AfA. For 17 of 18 loci, at least one SNP was nominally associated with FG in AfAs. Four loci were significantly associated with FG (GCK, p = 5.8 × 10(-8); MTNR1B, p = 8.5 × 10(-9); and FADS1, p = 2.2 × 10(-4)) or FI (GCKR, p = 5.9 × 10(-4)). At GCK and MTNR1B the EuA and AfA SNPs represented the same signal, while at FADS1, and GCKR, the EuA and best AfA SNPs were weakly correlated (r(2) <0.2), suggesting allelic heterogeneity for association with FG at these loci.

CONCLUSIONS/INTERPRETATION

Few glycaemic SNPs showed strict evidence of transferability from EuA to AfAs. Four loci were significantly associated in both AfAs and those with EuA after accounting for varying LD across ancestral groups, with new signals emerging to aid fine-mapping.

Activity participation intensity is associated with skeletal development in pre-pubertal children with developmental coordination disorder

PURPOSE

This study aimed (1) to compare the skeletal maturity and activity participation pattern between children with and without developmental coordination disorder (DCD); and (2) to determine whether activity participation pattern was associated with the skeletal development among children with DCD.

MATERIALS AND METHODS

Thirty-three children with DCD (mean age: 7.76 years) and 30 typically developing children (mean age: 7.60 years) were recruited. Skeletal maturity was assessed with the Sunlight BonAge system. Motor ability was evaluated by the Movement assessment battery for Children-2 (MABC-2). Participation patterns were evaluated using the Children Assessment of Participation and Enjoyment assessment. Analysis of variance was used to compare the outcome variables between the two groups. Multiple regression analysis was performed to examine the relationship between skeletal development, motor performance and activity participation intensity in children with DCD.

RESULTS

The DCD group had significantly delayed skeletal development, lower MABC-2 derived scores, and participated less intensely in various types of physical activities than their typically developing peers. After accounting for the effects of age and sex, activity participation intensity score remained significantly associated with delay in skeletal development, explaining 28.0% of the variance (F(change1, 29)=11.341, p=0.002).

CONCLUSION

Skeletal development is delayed in pre-pubertal children with DCD. Limited activity participation intensity appears to be one of the contributing factors.

Induction of microRNA-24 by HIF-1 protects against ischemic injury in rat cardiomyocytes

MicroRNAs are emerging as important regulators of cardiac function. This study investigated the role of microRNA-24 (miR-24) in ischemic cardiomyocytes, based on the observation that miR-24 expression was significantly enhanced in the ischemic myocardium of rats. Using primary cultured rat cardiomyocytes, cell injury was induced by ischemic conditions, and the cells were evaluated for changes in lactate dehydrogenase (LDH) release, cell viability, apoptosis and necrosis. The results showed that miR-24 was increased in myocytes exposed to ischemia. When miR-24 was further overexpressed in ischemic myocytes using the mimic RNA sequence, LDH release was reduced, cell viability was enhanced, and apoptosis and necrosis rates were both decreased. By contrast, a deficiency in miR-24 resulted in the largest LDH release, lowest cell viability and highest apoptosis and necrosis rates in normal and ischemic myocytes, with significant changes compared to that of non-transfected myocytes. Additionally, the mRNA and protein levels of the pro-apoptotic gene, BCL2L11, were down-regulated by miR-24 overexpression and up-regulated by miR-24 deficiency. The luciferase reporter assay confirmed BCL2L11 to be a target of miR-24. Overall, this study showed a protective role for miR-24 against myocardial ischemia by inhibiting BCL2L11, and may represent a potential novel treatment for ischemic heart disease.

High-efficiency matrix modulus-induced cardiac differentiation of human mesenchymal stem cells inside a thermosensitive hydrogel

Mesenchymal stem cells (MSCs) experience an extremely low rate of cardiac differentiation after transplantation into infarcted hearts, in part due to the inability of stiff scar tissue to support differentiation. We hypothesized that delivering MSCs in a hydrogel with a modulus matched to that of native heart tissue should stimulate MSC differentiation into cardiac cells. We have developed a thermosensitive and injectable hydrogel suitable for the delivery of cells into the heart, and found that the appropriate gel modulus can differentiate MSCs into cardiac cells with high efficiency. The hydrogel was based on N-isopropylacrylamide, N-acryloxysuccinimide, acrylic acid and poly(trimethylene carbonate)-hydroxyethyl methacrylate. The hydrogel solution can be readily injected through needles commonly used for heart injection, and is capable of gelling within 7s at 37°C. The formed gels were highly flexible, with breaking strains (>300%) higher than that of native heart tissue and moduli within the range of native heart tissue (1-140 kPa). Controlling the concentration of the hydrogel solution resulted in hydrogels with three different moduli: 16, 45 and 65 kPa. The moduli were decoupled from the gel water content and oxygen diffusion, parameters that can also influence cell differentiation. MSCs survived in the hydrogels throughout the entire culture period, and it was observed that gel stiffness did not affect cell survival. After 14 days of culture, more than 76% of MSCs had differentiated into cardiac cells in the 45 and 65 kPa gels, as confirmed by the expression of cardiac markers at both the gene and protein levels. MSCs in the hydrogel with the 65 kPa modulus had the highest differentiation efficiency. The differentiated cells also developed calcium channels that imparted an electrophysiological property, and gap junctions for cell-cell communication. The efficiency of differentiation reported in this study was much higher than for the differentiation approaches described in the literature, such as chemical induction and co-culture of MSCs and cardiomyocytes. These results indicate that the novel hydrogel holds great promise for delivering MSCs into an infarcted heart for the generation of new heart tissue.

Investigation of space-time clusters and geospatial hot spots for the occurrence of tuberculosis in Beijing

OBJECTIVE

To characterise the geographic and spatiotemporal distribution of confirmed tuberculosis (TB) cases in Beijing between 2005 and 2009.

DESIGN

The yearly notification rate maps were used to describe the distribution of confirmed adult TB patients. Spatial autocorrelation (Moran's I) and hot-spot analysis were adopted to detect the clusters and hot spots of TB.

RESULTS

The TB incidence rate (cases per 100,000 population) in Beijing increased from 29.8 in 2005 to 35.0 in 2009. The incidence rate was significantly higher in the Urban Development New District and the Ecologic Reservation Development District (>30/100,000) than in the other districts. There was a significant spatial autocorrelation throughout the city (u = 2.58, P = 0.01). Evident clusters were observed in the Capital Functional Core District and the Urban Function Extension District (G(i)* > 1).

CONCLUSION

Spatial autocorrelation and hot-spot analysis may serve as efficient tools to detect space-time clusters and geospatial hot spots of TB incidence. Between 2005 and 2009, TB incidence in Beijing showed population density and mobility-dependent and eco-social status-dependent space-time clusters and geospatial hot spots.

Inhibition of ASK1-p38 pathway prevents neural cell death following optic nerve injury

Optic nerve injury (ONI) induces retinal ganglion cell (RGC) death and optic nerve atrophy that lead to visual loss. Apoptosis signal-regulating kinase 1 (ASK1) is an evolutionarily conserved mitogen-activated protein kinase (MAPK) kinase kinase and has an important role in stress-induced RGC apoptosis. In this study, we found that ONI-induced p38 activation and RGC loss were suppressed in ASK1-deficient mice. Sequential in vivo retinal imaging revealed that post-ONI treatment with a p38 inhibitor into the eyeball was effective for RGC protection. ONI-induced monocyte chemotactic protein-1 production in RGCs and microglial accumulation around RGCs were suppressed in ASK1-deficient mice. In addition, the productions of tumor necrosis factor and inducible nitric oxide synthase in microglia were decreased when the ASK1-p38 pathway was blocked. These results suggest that ASK1 activation in both neural and glial cells is involved in neural cell death, and that pharmacological interruption of ASK1-p38 pathways could be beneficial in the treatment of ONI.

Creating 3D angiogenic growth factor gradients in fibrous constructs to guide fast angiogenesis

Fast angiogenesis in 3D fibrous constructs that mimic the morphology of the extracellular matrix remains challenging due to limited porosity in the densely packed constructs. We investigated whether mimicking the in vivo chemotaxis microenvironment for native blood vessel formation would stimulate angiogenesis in the fibrous constructs. The chemotaxis microenvironment was created by introducing 3D angiogenic growth factor gradients into the constructs. We have developed a technique that can quickly fabricate (∼40 min) such 3D gradients by simultaneously electrospinning polycaprolactone (PCL) fibers, encapsulating gradient amount of bFGF (stabilized by heparin) into poly(lactide-co-glycolide) (PLGA) microspheres, and electrospraying the microspheres into PCL fibers. Gradient formation was confirmed by fluorescence microscopy. Gradients with different steepnesses were obtained by modulating the initial concentration of the bFGF solution. All of the constructs were able to sustainedly release bioactive bFGF over a 28 day period. The release kinetics was dependent on the bFGF loading and steepness of the gradient. In vitro cell migration study demonstrated that bFGF gradients significantly increased the depth of cell migration. To assess the efficacy of bFGF gradients in inducing angiogenesis, we implanted constructs subcutaneously using mouse model. bFGF gradients significantly promoted cell penetration into the constructs. After 10 days of implantation, a high density of mature blood vessels (positive to both CD31 and α-SMA) were formed in the constructs. Vessel density was increased with the increase in steepness of the bFGF gradient. These gradient constructs may have potential to engineer vascularized tissues for various applications.

Insulin clearance: confirmation as a highly heritable trait, and genome-wide linkage analysis

AIMS/HYPOTHESIS

We have previously documented a high heritability of insulin clearance in a Hispanic cohort. Here, our goal was to confirm the high heritability in a second cohort and search for genetic loci contributing to insulin clearance.

METHODS

Hyperinsulinaemic-euglycaemic clamps were performed in 513 participants from 140 Hispanic families. Heritability was estimated for clamp-derived insulin clearance and a two-phase genome-wide linkage scan was conducted using a variance components approach. Linkage peaks were further investigated by candidate gene association analysis in two cohorts.

RESULTS

The covariate-adjusted heritability of insulin clearance was 73%, indicating that the majority of the phenotypic variance is due to genetic factors. In the Phase 1 linkage scan, no signals with a logarithm of odds (LOD) score >2 were detected. In the Phase 2 scan, two linkage peaks with an LOD >2 for insulin clearance were identified on chromosomes 15 (LOD 3.62) and 20 (LOD 2.43). These loci harbour several promising candidate genes for insulin clearance, with 12 single nucleotide polymorphisms (SNPs) on chromosome 15 and six SNPs on chromosome 20 being associated with insulin clearance in both Hispanic cohorts.

CONCLUSIONS/INTERPRETATION

In a second Hispanic cohort, we confirmed that insulin clearance is a highly heritable trait and identified chromosomal loci that harbour genes regulating insulin clearance. The identification of such genes may improve our understanding of how the body clears insulin, thus leading to improved risk assessment, diagnosis, prevention and therapy of diabetes, as well as of other hyperinsulinaemic disorders, such as the metabolic syndrome and polycystic ovary syndrome.

Altered Aggrecan Synthesis and Collagen Expression Profiles in Chondrocytes from Patients with Kashin—Beck Disease and Osteoarthritis

OBJECTIVES: To investigate cell morphology, aggrecan expression, and type I, II, III and X collagen expression in chondrocytes from adults with Kashin—Beck disease or osteoarthritis (OA). METHODS: Samples of knee articular cartilage were taken during surgery; cartilage samples obtained from fresh cadavers without arthritic disease were used as controls. Samples were digested with collagenase; isolated chondrocytes were cultured in monolayers. Aggrecan was detected by toluidine blue staining; collagen and aggrecan protein levels were evaluated by immuno cytochemistry and immunofluorescence staining. RESULTS: Samples were obtained from six participants per group. Aggrecan and type II collagen levels in chondrocytes from patients were significantly lower than those from controls, but levels of type I, III and X collagen were enhanced in patients compared with controls. Production of type III and X collagen was higher in chondrocytes from patients with Kashin—Beck disease than in those from OA patients. CONCLUSIONS: Biochemical and morphological mechanisms underlying Kashin—Beck disease and OA include enhanced dedifferentiation and hypertrophy of chondrocytes, increased type I, III and X collagen levels, and suppressed type II collagen and aggrecan production compared with control samples.

Tumor suppressor menin mediates peripheral nerve injury-induced neuropathic pain through potentiating synaptic plasticity

Synaptic plasticity is a crucial step in the development of central sensitization in the pathogenesis of neuropathic hyperalgesia. Menin, the product of the multiple endocrine neoplasia type 1 (MEN1) gene, possesses the property of synaptogenesis which plays an essential role in neuronal activity. We tested the contributing role of spinal menin in peripheral nerve injury-induced neuropathic hypersensitivity through modulating neuronal synaptic plasticity. After approval by the Institutional Animal Care and Use Committee, nociceptive responses were detected with von Frey filaments and thermal plate after spared nerve injury in C57BL/6 mice who were treated with either intrathecal antisense oligonucleotide of MEN1 (ASO) or vehicle. Extracellular spontaneous discharge frequency, field excitatory postsynaptic potential (fEPSP), and monosynaptic excitatory postsynaptic currents (EPSCs) were measured electrophysiologically. Intrathecal ASO alleviated nerve injury-induced mechanical and thermal hypersensitivity. Upregulated spinal menin after nerve injury colocalized with NeuN in the superficial laminae; genetic knockdown of spinal menin reduced nerve injury induced in vivo spontaneous activity and instantaneous frequency and in vitro field potentials; ASO decreased the frequency and amplitude of monosynaptic EPSCs, and reduced synaptic strength and total charge. Collectively, these findings highlight the role of upregulated neuronal menin in the spinal cord in potentiating spinal synaptic plasticity in peripheral nerve injury-induced neuropathic hypersensitivity.

Draft genome sequence of Streptomyces coelicoflavus ZG0656 reveals the putative biosynthetic gene cluster of acarviostatin family α-amylase inhibitors

AIMS

The aims of this study are to obtain the draft genome sequence of Streptomyces coelicoflavus ZG0656, which produces novel acarviostatin family α-amylase inhibitors, and then to reveal the putative acarviostatin-related gene cluster and the biosynthetic pathway.

METHODS AND RESULTS

The draft genome sequence of S. coelicoflavus ZG0656 was generated using a shotgun approach employing a combination of 454 and Solexa sequencing technologies. Genome analysis revealed a putative gene cluster for acarviostatin biosynthesis, termed sct-cluster. The cluster contains 13 acarviostatin synthetic genes, six transporter genes, four starch degrading or transglycosylation enzyme genes and two regulator genes. On the basis of bioinformatic analysis, we proposed a putative biosynthetic pathway of acarviostatins. The intracellular steps produce a structural core, acarviostatin I00-7-P, and the extracellular assemblies lead to diverse acarviostatin end products.

CONCLUSIONS

The draft genome sequence of S. coelicoflavus ZG0656 revealed the putative biosynthetic gene cluster of acarviostatins and a putative pathway of acarviostatin production.

SIGNIFICANCE AND IMPACT OF THE STUDY

To our knowledge, S. coelicoflavus ZG0656 is the first strain in this species for which a genome sequence has been reported. The analysis of sct-cluster provided important insights into the biosynthesis of acarviostatins. This work will be a platform for producing novel variants and yield improvement.

Development and validation of a quality of life instrument for Kashin-Beck disease: an endemic osteoarthritis in China

OBJECTIVES

To develop and validate a disease-specific Quality of Life (QOL) measure for a specialized osteoarthritis (OA)-Kashin-Beck disease (KBD).

METHODS

The standard methodology used for developing QOL instruments was employed. In phase 1, initially a group of health care professionals (HCPs) and KBD patient defined the overall concept of KBDQOL. It was followed by generation of an item pool through literature review, in-depth interview of 20 KBD patients and eight KBD HCPs and four focus group discussions. In phase 2, 368 KBD patients were interviewed and the reinterview of 95 participants, 10-14 days later assessed the reproducibility of the KBDQOL instrument.

RESULTS

A 37 items draft instrument was devised during phase 1. Principal Component Analysis (PCA) revealed six domains: physical function, activity limitation, social support, economics, mental health, and general health. Cronbach's alphas of six domains ranged from 0.77 to 0.90. The test-retest reliability (intraclass co-relation coefficient) of six domains was satisfactory, and ranged from 0.73 to 0.90. The smallest detectable change ranged from 13.2 to 30.2 points at the individual level and from 1.4 to 3.1 points at the group level for different domains. The construct validity was adequate when co-related with the EQ-5D (spearman co-relation coefficients: 0.49-0.61) and WHOQOL-BREF (spearman co-relation coefficients: 0.53-0.68). This resulted into the final version of KBDQOL instrument having 28 items and six domains.

CONCLUSIONS

The KBDQOL is a simple and easy to use 28-item six dimensional questionnaire. The measure has been developed as a true patient-based questionnaire and demonstrates good measurement properties.

Lysine-specific demethylase 1: an epigenetic regulator of salt-sensitive hypertension

BACKGROUND

Hypertension (HTN) represents a complex heritable disease in which environmental factors may directly affect gene function via epigenetic mechanisms. The aim of this study was to test the hypothesis that dietary salt influences the activity of a histone-modifying enzyme, lysine-specific demethylase 1 (LSD-1), which in turn is associated with salt-sensitivity of blood pressure (BP).

METHODS

Animal and human studies were performed. Salt-sensitivity of LSD-1 expression was assessed in wild-type (WT) and LSD-1 heterozygote knockout (LSD-1(+/-)) mice. Clinical relevance was tested by multivariate associations between single-nuclear polymorphisms (SNPs) in the LSD-1 gene and salt-sensitivity of BP, with control of dietary sodium, in a primary African-American hypertensive cohort and two replication hypertensive cohorts (Caucasian and Mexican-American).

RESULTS

LSD-1 expression was modified by dietary salt in WT mice with lower levels associated with liberal salt intake. LSD-1(+/-) mice expressed lower LSD-1 protein levels than WT mice in kidney tissue. Similar to LSD-1(+/-) mice, African-American minor allele carriers of two LSD-1 SNPs displayed greater change in systolic BP (SBP) in response to change from low to liberal salt diet (rs671357, P = 0.01; rs587168, P = 0.005). This association was replicated in the Hispanic (rs587168, P = 0.04) but not the Caucasian cohort. Exploratory analyses demonstrated decreased serum aldosterone concentrations in African-American minor allele carriers similar to findings in the LSD-1(+/-) mice, decreased α-EnaC expression in LSD-1(+/-) mice, and impaired renovascular responsiveness to salt loading in minor allele carriers.

CONCLUSION

The results of this translational research study support a role for LSD-1 in the pathogenesis of salt-sensitive HTN.

SU-E-J-112: A Splatting Method to Generate DRRs for Deformed CT Volume

PURPOSE

To develop an efficient algorithm for generating high-quality digitally reconstructed radiographs (DRRs) for regularly and irregularly sampled volumes based on a splatting method with dynamic elliptical Gaussian kernels, and to evaluate this method using ray tracing.

METHODS

The traditional ray tracing method, which takes every intersected voxel into account, produces high quality DRRs but is very time consuming. Additionally, it is not suitable for handling irregularly-sampled volumes since it always requires image re-sampling, which leads to inaccuracy. We present a splatting approach to compute the 'footprint function', facilitating efficient perspective projection of elliptical Gaussian kernels at very low cost. This reported framework allows dealing with both regularly and irregularly sampled volumes effectively and efficiently. An XCAT digital phantom was used to generate 3D chest volumes at different respiratory phases, and CT projections are generated using ray tracing and the splatting method, respectively. Normalized cross correlation (NCC) is applied to evaluate the DRR similarity of two methods.

RESULTS

Respiratory Phases one and four are used as volume datasets from the 4D XCAT digital phantom as they represent the lung at end inhale and end exhale, respectively. The dataset of Phase one is the basic regularly-sampled volume while the dataset of Phase four is deformed from that of Phase one, and resampled to a regularly sampled dataset for the ray tracing method. NCC between splatting and ray tracing DRRs are 0.9980 and 0.9977 for Phase one and Phase four, respectively. The calculation speed of the splatting method is 3 times faster than that of ray tracing.

CONCLUSIONS

Our splatting approach can generate high-quality DRRs efficiently, and is a good alternative for current DRR generation techniques for deformed volume datasets. This research is supported by CPRIT Individual Investigator Award RP110329.