Meta-analyses of HFE variants in coronary heart disease

AIM

HFE gene variants can cause hereditary hemochromatosis (HH) that often comes along with an increased risk of coronary heart disease (CHD). The goal of our study is to assess the contribution of four HFE gene variants to the risk of CHD.

METHODS AND RESULTS

We conducted four meta-analyses of the studies examining the association between four HFE gene variants and the risk of CHD. A systematic search was conducted using MEDLINE, EMBASE, Web of Science and China National Knowledge Infrastructure (CNKI), Wanfang Chinese Periodical.

RESULTS

Meta-analyses showed that HFE rs1799945-G allele was associated with a 6% increased risk of CHD (P=0.02, odds ratio (OR)=1.06, 95% confidence interval (CI)=1.01-1.11). However, no association between the other three HFE gene variants (rs1800562, rs1800730, and rs9366637) and CHD risk was observed by the meta-analyses (all P values>0.05). In addition, the results of our case-control study indicated that rs1800562 and rs1800730 were monomorphic, and that rs1799945 and rs9366637 were not associated with CHD in Han Chinese.

CONCLUSIONS

Our meta-analysis suggested that a significant association existed between rs1799945 mutation and CHD, although this mutation was rare in Han Chinese.

Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.

Physical activity for children in special school environment

1. We assessed children's physical activity (PA) in structured (physical education) and unstructured (recess, lunch, before and after school) periods in special schools and examined its association with modifiable area contextual characteristics. 2. Children with disabilities were not highly active, but were more active during recess and lunch periods than at other times including physical education classes. 3. Areas were often not accessible during unstructured settings. Children were more active in areas when supervision and organised activities were provided. 4. Providing an interactive game during free play did not significantly increase group's PA. 5. Children's PA accrual is influenced by contextual characteristics of the school environment. There is a need to make areas more accessible and to use social marketing and programming to attract more users. School and health professionals should modify contextual characteristics by providing more direct supervision and organised activities during free play.

Positive correlation between variants of lipid metabolism‑related genes and coronary heart disease

Four gene variants related to lipid metabolism (including the rs562338 and rs503662 variants of the APOB gene, the rs7767084 variant of the LPA gene and the rs2246942 variant of the LIPA gene) have been shown to be associated with coronary heart disease (CHD). The aim of the present study was to assess their association with CHD in the Han Chinese population and to assess the contribution of these gene variants to CHD. Using the standardized coronary angiography method, we enrolled 290 CHD patients and 193 non-CHD patients as non-CHD controls from Lihuili Hospital (Ningbo, China). In addition, we recruited 330 unrelated healthy volunteers as healthy controls from the Xi Men Community (Ningbo, China). Our results demonstrated that the rs503662 and rs562338 variants of the APOB gene were extremely rare in the Han Chinese population (minor allele frequency <1%). Genotype rs2246942-GG of the LIPA gene was associated with an increased risk of CHD [CHD cases versus healthy controls: P=0.04; odds ratio (OR)=1.63; 95% confidence interval (CI)=1.02–2.60). Genotype rs7767084-CC of the LPA gene was identified as a protective factor against CHD in females (CHD cases versus non-CHD controls: P=0.04, OR=0.21; CHD cases versus healthy controls: P=0.02, OR=0.21). The results of our meta-analysis indicated that rs7767084 was not associated with a high risk of CHD (P=0.83; combined OR=0.93; 95% CI=0.47–1.85). In the present study, two single nucleotide polymorphisms (SNPs) of genes involved in lipid metabolism (rs2246942 and rs7767084) were identified to be significantly associated with CHD in the Han Chinese population. Specifically, rs2246942-GG of the LIPA gene was a risk factor for CHD, while rs7767084-CC of the LPA gene was a protective factor against CHD in females. However, our meta-analysis indicated that rs7767084 is not associated with a higher risk of CHD.

The novel BH-3 mimetic apogossypolone induces Beclin-1- and ROS-mediated autophagy in human hepatocellular carcinoma [corrected] cells

Apogossypolone (ApoG2), a novel derivative of gossypol, exhibits superior antitumor activity in Bcl-2 transgenic mice, and induces autophagy in several cancer cells. However, the detailed mechanisms are not well known. In the present study, we showed that ApoG2 induced autophagy through Beclin-1- and reactive oxygen species (ROS)-dependent manners in human hepatocellular carcinoma (HCC) cells. Incubating the HCC cell with ApoG2 abrogated the interaction of Beclin-1 and Bcl-2/xL, stimulated ROS generation, increased phosphorylation of ERK and JNK, and HMGB1 translocation from the nucleus to cytoplasm while suppressing mTOR. Moreover, inhibition of the ROS-mediated autophagy by antioxidant N-acetyl-cysteine (NAC) potentiates ApoG2-induced apoptosis and cell killing. Our results show that ApoG2 induced protective autophagy in HCC cells, partly due to ROS generation, suggesting that antioxidant may serve as a potential chemosensitizer to enhance cancer cell death through blocking ApoG2-stimulated autophagy. Our novel insights may facilitate the rational design of clinical trials for Bcl-2-targeted cancer therapy.

Association between PCSK9 and LDLR gene polymorphisms with coronary heart disease: case-control study and meta-analysis

OBJECTIVE

To explore the association of rs11206510 (PCSK9 gene) and rs1122608 (LDLR gene) polymorphisms with coronary heart disease (CHD) in Han Chinese.

METHODS

A total of 813 participants (290 CHD cases, 193 non-CHD controls and 330 healthy controls) were recruited in the case-control study. DNA genotyping was performed on the SEQUENOM® Mass-ARRAY iPLEX® platform. χ(2)-test was used to compare the genotype distribution and allele frequencies. Two meta-analyses were performed to establish the association between the two polymorphisms with CHD.

RESULTS

No significant associations between the two SNPs and the risk of CHD were observed in the present study. The meta-analysis of rs11206510 of PCSK9 gene comprises 11 case-control studies with a total of 69,054 participants. Significant heterogeneity was observed in Caucasian population in subgroup analysis of the association studies of rs11206510 with CHD (P=0.003, I(2)=67.2%). The meta-analysis of LDLR gene rs1122608 polymorphism comprises 7 case-control studies with a total of 20,456 participants and the heterogeneity of seven studies was minimal (P=0.148, I(2)=36.7%).

CONCLUSION

The results of the meta-analyses indicated that both SNPs were associated with CHD in Caucasians (P<0.05) but not in Asians. The results from our case-control study and meta-analyses might be explained by genetic heterogeneity in the susceptibility of CHD and ethnic differences between Asians and Caucasians.

An association study between genetic polymorphisms related to lipoprotein-associated phospholipase A(2) and coronary heart disease

Previous genome-wide association studies (GWAS) have revealed seven single nucleotide polymorphisms (SNPs) that affect lipoprotein-associated phospholipase A₂ (Lp-PLA₂) activity or levels in American and European individuals. A total of 290 coronary heart disease (CHD) patients, 198 non-CHD patients and 331 unrelated healthy volunteers were recruited for the present case-control study of Han Chinese. Four SNPs (rs964184 of ZNF259, rs7528419 of CELSR2 and rs7756935 and rs1805017 of PLA2G7) were shown to be significantly associated with CHD. The rs964184-G allele of the ZNF259 gene was identified as a risk factor of CHD in females (odds ratio (OR) =1.49, 95% confidence interval (CI) =1.00–2.22, P=0.05). The rs7528419-G allele of the CELSR2 gene was protective against CHD in males (OR=0.48, 95% CI=0.25–0.93, P=0.04). The other two alleles (rs7756935-C and rs1805017-A) of the PLA2G7 gene acted as protective factors against CHD in females (rs7756935-C: OR=0.59, 95% CI=0.35–1.00, P=0.05; rs1805017-A: OR=0.51, 95% CI=0.28–0.93, P=0.03). Moreover, rs1805017 of the PLA2G7 gene was associated with the severity of CHD only in females (r²=0.02, P=0.04). We identified four Lp-PLA₂-associated SNPs significantly associated with CHD in a Han Chinese population. Specifically, rs7528419 was protective factor against CHD in males, while the other two SNPs (rs7756935 and rs1805017 of the PLA2G7 gene) were protective factors against CHD in females and rs964184 of the ZNF259 gene was regarded as a risk factor for CHD in females.

Meta-analyses of KIF6 Trp719Arg in coronary heart disease and statin therapeutic effect

Aims

The goal of our study is to assess the contribution of KIF6 Trp719Arg to both the risk of CHD and the efficacy of statin therapy in CHD patients.

Methods and Results

Meta-analysis of 8 prospective studies among 77,400 Caucasians provides evidence that 719Arg increases the risk of CHD (P<0.001, HR = 1.27, 95% CI = 1.15–1.41). However, another meta-analysis of 7 case-control studies among 65,200 individuals fails to find a significant relationship between Trp719Arg and the risk of CHD (P = 0.642, OR = 1.02, 95% CI = 0.95–1.08). This suggests that the contribution of Trp719Arg to CHD varies in different ethnic groups. Additional meta-analysis also shows that statin therapy only benefit the vascular patients carry 719Arg allele (P<0.001, relative ratio (RR) = 0.60, 95% CI = 0.54–0.67). To examine the role of this genetic variant in CHD risk in Han Chinese, we have conducted a case-control study with 289 CHD cases, 193 non-CHD controls, and 329 unrelated healthy volunteers as healthy controls. On post hoc analysis, significant allele frequency difference of 719Arg is observed between female CHD cases and female total controls under the dominant model (P = 0.04, χ² = 4.228, df = 1, odd ratio (OR) = 1.979, 95% confidence interval (CI) = 1.023–3.828). Similar trends are observed for post hoc analysis between female CHD cases and female healthy controls (dominant model: P = 0.04, χ² = 4.231, df = 1, OR = 2.015, 95% CI = 1.024–3.964). Non-genetic CHD risk factors are not controlled in these analyses.

Conclusions

Our meta-analysis demonstrates the role of Trp719Arg of KIF6 gene in the risk of CHD in Caucasians. The meta-analysis also suggests the role of this variant in statin therapeutic response in vascular diseases. Our case-control study suggests that Trp719Arg of KIF6 gene is associated with CHD in female Han Chinese through a post hoc analysis.

Positive association between rs10918859 of the NOS1AP gene and coronary heart disease in male Han Chinese

Westaway et al. have revealed a significant association between common variants of calsequestrin-2 (CASQ2) and nitric oxide synthase 1 (neuronal) adaptor protein (NOS1AP) and the risk of sudden death in patients of coronary heart disease (CHD). In light of the findings, we aim to explore the association between variants of the two genes and CHD risk in Han Chinese. Our results show a significant contribution of rs10918859 of the NOS1AP gene to CHD in Han Chinese (genotype: χ(2)=8.33, df=2, p=0.015; allele: χ(2)=4.00, df=1, p=0.047, odds ratio [OR]=1.44, 95% confidence interval [CI]=1.00-2.05). The association of rs10918859 with CHD is seen only in men (genotype: χ(2)=7.81, df=2, p=0.02; allele: χ(2)=4.49, df=1, p=0.03, OR=1.66, 95% CI=1.03-2.66). Moreover, rs10918859 is likely to exert its effect under a dominant model in men (χ(2)=7.6, df=1, p=0.005, OR=2.46, 95% CI=1.29-4.71). No association is observed between CASQ2 variants and CHD risk. The frequencies of rs12084280-C and rs10918859-A are higher in Han Chinese (36.7% and 41.6%) than those in Europeans (11% and 19.4%, respectively). These ethnic differences imply that further validation of NOS1AP in the susceptibility of CHD in other populations is warranted. We confirm that rs10918859 of the NOS1AP gene is associated with CHD in Han Chinese. In addition, here we report a gender effect in the association between rs10918859 of the NOS1AP gene and CHD.

SU-E-T-603: Influence of PTV Delineation at Air Cavity Interface on Tomotherapy Plan Quality

PURPOSE

To determine if different ways in PTV delineation at an air cavity interface yield differences in overall plan quality and treatment efficiency Methods: Three different PTVs were used for treating a patient whose CTV surrounded a large air cavity created by a resected hard palate. The CTV lined the surface of the air cavity while PTV1 included the entire air cavity, PTV2 extended 4mm from the surface of the cavity into air, and PTV3 was reduced 4mm within the surface of the cavity. Tomotherapy plans were generated for all three PTVs. During each planning, all constraints to target and normal structures were kept constant along with the number of optimizations. Same planning process was repeated on a head and neck digital phantom with mock target, normal structures and cavity.

RESULTS

Three treatment planning approaches showed no significantly different target coverage in terms of minimum or maximum dose to their respective PTVs. All plans attained 95% coverage of the CTV and PTV by 100% of the prescription. The conformity index (CI) of the plans delivered to PTV1, PTV2, and PTV3 were 1.09, 1.11, and 1.18, respectively. The skin, optic nerves, brainstem and spinal cord all received similar maximum dose to their respective volumes for each plan within 1Gy. The monitor units required for each treatment plan were all within 6% of one another with PTV1 having the highest. For head and neck phantom, the CIs of three plans were 1.05, 1.21, and 1.18, respectively. The coverage of the phantom CTV and sparing of normal structures were nearly equivalent. The total treatment times were identical.

CONCLUSIONS

Tomotherapy planning is able to deliver dose to a head and neck PTV containing a large air cavity without compromising target coverage, sparing of normal tissues, or delivery time.

Intermediate-conductance Ca(2+) -activated potassium and volume-sensitive chloride channels in endothelial progenitor cells from rat bone marrow mononuclear cells

AIM

Bone marrow endothelial progenitor cells (BMEPCs) are believed to be a promising cell source for regenerative medicine; however, their electrophysiology properties have not been fully clarified, which is important to the clinical application of BMEPCs. The current study was designed to determine the transmembrane ion currents and mRNA expression levels of related ion channel subunits in rat BMEPCs.

METHODS

Bone marrow mononuclear cells were isolated by density gradient separation and cultured in EPC medium. The transmembrane ion currents were determined using whole-cell patch-voltage clamp technique, and the levels of mRNA and protein expressions of functional ionic channels were measured using RT-PCR and western immunoblot analysis.

RESULTS

We observed two types of ionic currents in undifferentiated rat BMEPCs. One was Ca(2+) -activated potassium current (I(kca) ), which was seen in approx. 90% of cells when 1 μm Ca(2+) was employed in pipette solution, and it was predominantly inhibited by intermediate-conductance I(kca) inhibitor clotrimazole. The other one was volume-sensitive chloride current (I(cl) ), which was detected in 85.7% of cells when BMEPCs were subjected to K(+) -free hypotonic extracellular solution, whose currents could be inhibited by 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB). The corresponding ion channel genes and proteins, KCNN4 for I(kca) and Clcn3 for I(cl) , were confirmed by RT-PCR and western immunoblot analysis of BMEPCs.

CONCLUSION

Our results demonstrated for the first time that rat BMEPCs expressed intermediate-conductance Ca(2+) -activated potassium currents and volume-sensitive chloride currents, and corresponding genes and proteins of these two channels are KCNN4 and Clcn3 respectively.