CX3CL1/CX3CR1 and CCL2/CCR2 Chemokine/Chemokine Receptor Complex in Patients with AMD

Purpose

The chemokine receptors CX3CR1 and CCR2 have been implicated in the development of age-related macular degeneration (AMD). The evidence is mainly derived from experimental cell studies and murine models of AMD. The purpose of this study was to investigate the association between expression of CX3CR1 and CCR2 on different leukocyte subsets and AMD. Furthermore we measured the plasma levels of ligands CX3CL1 and CCL2.

Methods

Patients attending our department were asked to participate in the study. The diagnosis of AMD was based on clinical examination and multimodal imaging techniques. Chemokine plasma level and chemokine receptor expression were measured by flow-cytometry.

Results

A total of 150 participants were included. We found a significantly lower expression of CX3CR1 on CD8⁺ T cells in the neovascular AMD group compared to the control group (p = 0.04). We found a significant positive correlation between CCR2 and CX3CR1 expression on CD8⁺ cells (r = 0.727, p = 0.0001). We found no difference in plasma levels of CX3CL1 and CCL2 among the groups.

Conclusions

Our results show a down regulation of CX3CR1 on CD8⁺ cells; this correlated to a low expression of CCR2 on CD8⁺ cells. Further studies are needed to elucidate the possible role of this cell type in AMD development.     

Does Minimally-Invasive Pancreaticoduodenectomy Have Advantages over Its Open Method? A Meta-Analysis of Retrospective Studies

Background

While more and more open procedures now routinely performed using laparoscopy, minimally invasive pancreaticoduodenectomy (MIPD) remains one of the most challenging abdominal procedures. Therefore, we carried out this meta-analysis to evaluate whether MIPD is safe, feasible and worthwhile.

Methods

PubMed, EMBASE, and Cochrane Library were searched to identify studies published between January 1994 and November 2013 comparing MIPD with open pancreaticoduodenectomy (OPD). Intraoperative outcomes, oncologic safety, postoperative complications, and postoperative recovery were evaluated.

Results

11 retrospective studies representing 869 patients (327 MIPDs, 542 OPDs) were included. MIPD was associated with a reduction in estimated blood loss (MD −361.93 ml, 95% CI −519.22 to −204.63 ml, p<0.001, I² = 94%), wound infection (OR 0.41, 95% CI 0.22 to 0.78, p = 0.007, I² = 0%), and hospital stay (MD −2.64 d, 95% CI −4.23 to −1.05 d, p = 0.001, I² = 78%). However, it brings longer operative time (MD 105 min, 95% CI 49.73 to 160.26 min, p<0.001, I² = 93%). There were no significant differences between the two procedures in likelihood of overall complications (p = 0.05), pancreatic fistula (PF) (p = 0.86), delayed gastric empting (DGE) (p = 0.96), positive surgical margins (p = 0.07), retrieval of lymph nodes (p = 0.48), reoperation (p = 0.16) and mortality (p = 0.64).

Conclusions

Our results suggest that MIPD is currently safe, feasible and worthwhile. But considering the selection bias, complexity of MIPD and lack of long-term oncologic outcomes, we suggest it be performed in a high-volume pancreatic surgery center in selected patients.     

Effects of T-Type Calcium Channel Blockers on Renal Function and Aldosterone in Patients with Hypertension: A Systematic Review and Meta-Analysis

Background

High blood pressure can cause kidney damage, which can increase blood pressure, leading to a vicious cycle. It is not clear whether the protective effects of T-type calcium channel blockers (T-type CCBs) on renal function are better than those of L-type CCBs or renin-angiotensin system (RAS) antagonists in patients with hypertension.

Methods and Findings

PUBMED, MEDLINE, EMBASE, OVID, Web of Science, Cochrane, CNKI, MEDCH, VIP, and WANFANG databases were searched for clinical trials published in English or Chinese from January 1, 1990, to December 31, 2013. The weighted mean difference (WMD) and 95% confidence interval (CI) were calculated and reported. A total of 1494 reports were collected, of which 24 studies with 1,696 participants (including 809 reports comparing T-type CCBs versus L-type CCBs and 887 reports comparing T-type CCB versus RAS antagonists) met the inclusion criteria. Compared with L-type CCBs, T-type CCBs resulted in a significant decline in aldosterone (mean difference = −15.19, 95% CI −19.65–−10.72, p<1×10⁻⁵), proteinuria (mean difference = −0.73, 95% CI −0.88–−0.57, p<1×10⁻⁵), protein to creatinine ratio (mean difference = −0.22, 95% CI −0.41–−0.03, p = 0.02), and urinary albumin to creatinine ratio (mean difference = −55.38, 95% CI −86.67–−24.09, p = 0.0005); no significant difference was noted for systolic blood pressure (SBP) (p = 0.76) and diastolic blood pressure (DBP) (p = 0.16). The effects of T-type CCBs did not significantly differ from those of RAS antagonists for SBP (p = 0.98), DBP (p = 0.86), glomerular filtration rate (p = 0.93), albuminuria (p = 0.97), creatinine clearance rate (p = 0.24), and serum creatinine (p = 0.27) in patients with hypertension.

Conclusion

In a pooled analysis of data from 24 studies measuring the effects of T-type CCBs on renal function and aldosterone, the protective effects of T-type CCBs on renal function were enhanced compared with L-type CCBs but did not differ from RAS antagonists. Their protective effects on renal function were independent of blood pressure.     

Association of rs780094 in GCKR with Metabolic Traits and Incident Diabetes and Cardiovascular Disease: The ARIC Study

Objective

The minor T-allele of rs780094 in the glucokinase regulator gene (GCKR) associates with a number of metabolic traits including higher triglyceride levels and improved glycemic regulation in study populations of mostly European ancestry. Using data from the Atherosclerosis Risk in Communities (ARIC) Study, we sought to replicate these findings, examine them in a large population-based sample of African American study participants, and to investigate independent associations with other metabolic traits in order to determine if variation in GKCR contributes to their observed clustering. In addition, we examined the association of rs780094 with incident diabetes, coronary heart disease (CHD), and stroke over up mean follow-up times of 8, 15, and 15 years, respectively.

Research Design and Methods

Race-stratified analyses were conducted among 10,929 white and 3,960 black participants aged 45–64 at baseline assuming an additive genetic model and using linear and logistic regression and Cox proportional hazards models.

Results

Previous findings replicated among white participants in multivariable adjusted models: the T-allele of rs780094 was associated with lower fasting glucose (p = 10⁻⁷) and insulin levels (p = 10⁻⁶), lower insulin resistance (HOMA-IR, p = 10⁻⁹), less prevalent diabetes (p = 10⁻⁶), and higher CRP (p = 10⁻⁸), 2-h postprandial glucose (OGTT, p = 10⁻⁶), and triglyceride levels (p = 10⁻³¹). Moreover, the T-allele was independently associated with higher HDL cholesterol levels (p = 0.022), metabolic syndrome prevalence (p = 0.043), and lower beta-cell function measured as HOMA-B (p = 0.011). Among black participants, the T-allele was associated only with higher triglyceride levels (p = 0.004) and lower insulin levels (p = 0.002) and HOMA-IR (p = 0.013). Prospectively, the T-allele was associated with reduced incidence of diabetes (p = 10⁻⁴) among white participants, but not with incidence of CHD or stroke.

Conclusions

Our findings indicate rs780094 has independent associations with multiple metabolic traits as well as incident diabetes, but not incident CHD or stroke. The magnitude of association between the SNP and most traits was of lower magnitude among African American compared to white participants.     

ZNF385B and VEGFA Are Strongly Differentially Expressed in Serous Ovarian Carcinomas and Correlate with Survival

Background

The oncogenesis of ovarian cancer is poorly understood. The aim of this study was to identify mRNAs differentially expressed between moderately and poorly differentiated (MD/PD) serous ovarian carcinomas (SC), serous ovarian borderline tumours (SBOT) and superficial scrapings from normal ovaries (SNO), and to correlate these mRNAs with clinical parameters including survival.

Methods

Differences in mRNA expression between MD/PD SC, SBOT and SNO were analyzed by global gene expression profiling (n = 23), validated by RT-qPCR (n = 41) and correlated with clinical parameters.

Results

Thirty mRNAs differentially expressed between MD/PD SC, SBOT and SNO were selected from the global gene expression analyses, and 21 were verified (p<0.01) by RT-qPCR. Of these, 13 mRNAs were differentially expressed in MD/PD SC compared with SNO (p<0.01) and were correlated with clinical parameters. ZNF385B was downregulated (FC = −130.5, p = 1.2×10⁻⁷) and correlated with overall survival (p = 0.03). VEGFA was upregulated (FC = 6.1, p = 6.0×10⁻⁶) and correlated with progression-free survival (p = 0.037). Increased levels of TPX2 and FOXM1 mRNAs (FC = 28.5, p = 2.7×10⁻¹⁰ and FC = 46.2, p = 5.6×10⁻⁴, respectively) correlated with normalization of CA125 (p = 0.03 and p = 0.044, respectively). Furthermore, we present a molecular pathway for MD/PD SC, including VEGFA, FOXM1, TPX2, BIRC5 and TOP2A, all significantly upregulated and directly interacting with TP53.

Conclusions

We have identified 21 mRNAs differentially expressed (p<0.01) between MD/PD SC, SBOT and SNO. Thirteen were differentially expressed in MD/PD SC, including ZNF385B and VEGFA correlating with survival, and FOXM1 and TPX2 with normalization of CA125. We also present a molecular pathway for MD/PD SC.     

The Interactive Effect of SIRT1 Promoter Region Polymorphism on Type 2 Diabetes Susceptibility in the North Indian Population

Our previous studies have implicated genes mainly involved in the activity of pancreatic β cells in type 2 diabetes (T2D) susceptibility in the North Indian population. Recent literature on the role of SIRT1 as a potential master switch modulating insulin secretion and regulating gene expression in pancreatic β cells has warranted an evaluation of SIRT1 promoter region polymorphisms in the North Indian population, which is the main focus of the present study. 1542 samples (692 T2D patients and 850 controls) were sequenced for the 1.46 kb region upstream the translation start site of the SIRT1 gene. We performed a functional characterization of the SIRT1 promoter region polymorphisms using luciferase assay and observed a single-nucleotide polymorphism (SNP), rs12778366, in association with SIRT1 expression. We propose that TT, the high-expressing genotype of SNP rs12778366 in the SIRT1 promoter region and present in >80% of the North Indian population, was favored under conditions of feast-famine cycles in evolution, which has turned out to be a cause of concern in the present sedentary lifestyle under ad libitum conditions. Case-control association analysis did not implicate rs12778366 in T2DM per se in the studied population. However, our earlier reported risk genotype combinations of mt-ND3, PGC1α, and UCP2-866, when compared with the protective genotype combinations, in the background of the high-expressing TT genotype of SIRT1 SNP rs12778366, showed a very high additive risk [corrected odd ratio (OR) = 8.91; p = 6.5×10⁻¹¹]. The risk level was considerably low in the genotype backgrounds of TX (OR = 6.68; p = 2.71×10⁻¹²) and CX (OR = 3.74; p = 4.0×10⁻³). In addition, we screened other reported T2D-associated polymorphisms: PIK3R1 rs3730089, IRS1 rs1801278, and PPP1R3 rs1799999, which did not show any significant association in North Indian population. The present paper emphasizes the importance of gene interactions in the biological pathways of T2D, a complex lifestyle disease.     

Central Nervous System PET-CT Imaging Reveals Regional Impairments in Pediatric Patients with Wolfram Syndrome

Wolfram syndrome (WFS) is inherited as an autosomal recessive disease with main clinical features of diabetes mellitus, optic atrophy, diabetes insipidus and deafness. However, various neurological defects may also be detected. The aim of this study was to evaluate aspects of brain structure and function using PET-CT (positron emission tomography and computed tomography) and MRI (magnetic resonance imaging) in pediatric patients with WFS. Regional changes in brain glucose metabolism were measured using standardized uptake values (SUVs) based on images of (¹⁸F) fluorodeoxyglucose (FDG) uptake in 7 WFS patients aged 10.1–16.0 years (mean 12.9±2.4) and in 20 healthy children aged 3–17.9 years (mean 12.8±4.1). In all patients the diagnosis of WFS was confirmed by DNA sequencing of the WFS1 gene. Hierarchical clustering showed remarkable similarities of glucose uptake patterns among WFS patients and their differences from the control group. SUV data were subsequently standardized for age groups <13 years old and>13 years old to account for developmental differences. Reduced SUVs in WFS patients as compared to the control group for the bilateral brain regions such as occipital lobe (−1.24±1.20 vs. −0.13±1.05; p = 0.028) and cerebellum (−1.11±0.69 vs. −0.204±1.00; p = 0.036) were observed and the same tendency for cingulate (−1.13±1.05 vs. −0.15±1.12; p = 0.056), temporal lobe (−1.10±0.98 vs. −0.15±1.10; p = 0.057), parietal lobe (−1.06±1.20 vs. −0.08±1.08; p = 0.058), central region (−1.01±1.04 vs. −0.09±1.06; p = 0.060), basal ganglia (−1.05±0.74 vs. −0.20±1.07; p = 0.066) and mesial temporal lobe (−1.06±0.82 vs. −0.26±1.08; p = 0.087) was also noticed. After adjusting for multiple hypothesis testing, the differences in glucose uptake were non-significant. For the first time, regional differences in brain glucose metabolism among patients with WFS were shown using PET-CT imaging.     

Genetic Variants Associated with Serum Thyroid Stimulating Hormone (TSH) Levels in European Americans and African Americans from the eMERGE Network

Thyroid stimulating hormone (TSH) hormone levels are normally tightly regulated within an individual; thus, relatively small variations may indicate thyroid disease. Genome-wide association studies (GWAS) have identified variants in PDE8B and FOXE1 that are associated with TSH levels. However, prior studies lacked racial/ethnic diversity, limiting the generalization of these findings to individuals of non-European ethnicities. The Electronic Medical Records and Genomics (eMERGE) Network is a collaboration across institutions with biobanks linked to electronic medical records (EMRs). The eMERGE Network uses EMR-derived phenotypes to perform GWAS in diverse populations for a variety of phenotypes. In this report, we identified serum TSH levels from 4,501 European American and 351 African American euthyroid individuals in the eMERGE Network with existing GWAS data. Tests of association were performed using linear regression and adjusted for age, sex, body mass index (BMI), and principal components, assuming an additive genetic model. Our results replicate the known association of PDE8B with serum TSH levels in European Americans (rs2046045 p = 1.85×10⁻¹⁷, β = 0.09). FOXE1 variants, associated with hypothyroidism, were not genome-wide significant (rs10759944: p = 1.08×10⁻⁶, β = −0.05). No SNPs reached genome-wide significance in African Americans. However, multiple known associations with TSH levels in European ancestry were nominally significant in African Americans, including PDE8B (rs2046045 p = 0.03, β = −0.09), VEGFA (rs11755845 p = 0.01, β = −0.13), and NFIA (rs334699 p = 1.50×10⁻³, β = −0.17). We found little evidence that SNPs previously associated with other thyroid-related disorders were associated with serum TSH levels in this study. These results support the previously reported association between PDE8B and serum TSH levels in European Americans and emphasize the need for additional genetic studies in more diverse populations.     

FCGR2B and FCRLB Gene Polymorphisms Associated with IgA Nephropathy

Background

IgA nephropathy (IgAN) is a complex syndrome characterized by deposition of IgA and IgA containing immune complexes (ICs) composed of IgG and complement C3 proteins in the mesangial area of glomeruli. The low-affinity receptors for the Fc region of IgG (FcγRs) are involved in autoantibody/immune complex-induced organ injury as well as ICs clearance. The aim of the study was to associate multiple polymorphisms within FCGR gene locus with IgAN in a large Chinese cohort.

Patients and Methods

60 single nucleotide polymorphisms (SNPs) spanning a 400 kb range within FCGR gene locus were analyzed in 2100 DNA samples from patients with biopsy proven IgAN and healthy age- and sex-matched controls from the same population in Chinese.

Results

Among the 60 SNPs investigated, 15 gene polymorphisms within FCGR gene locus (25%) were associated with susceptibility to IgAN. The most significantly associated SNPs within individual genes were FCGR2B rs12118043 (p = 8.74*10⁻³, OR 0.76, 95% CI 0.62–0.93), and FCRLB rs4657093 (p = 2.28*10⁻³, OR 0.77, 95% CI 0.65–0.91). Both conditional analysis and linkage disequilibrium analysis suggested they were independent signals associated with IgAN. Associations between FCGR2B rs12118043 and proteinuria (p = 3.65×10⁻²) as well as gross hematuria (p = 4.53×10⁻²), between FCRLB rs4657093 and levels of serum creatinine (p = 2.67×10⁻²) as well as eGFR (p = 5.41*10⁻³) were also observed. Electronic cis-expression quantative trait loci analysis supported their possible functional significance, with protective genotypes correlating lower gene expressions.

Conclusion

Our data from genetic associations and expression associations revealed potentially pathogenic roles of Fc receptor gene polymorphisms in IgAN.     

The Causal Effect of Vitamin D Binding Protein (DBP) Levels on Calcemic and Cardiometabolic Diseases: A Mendelian Randomization Study

Background

Observational studies have shown that vitamin D binding protein (DBP) levels, a key determinant of 25-hydroxy-vitamin D (25OHD) levels, and 25OHD levels themselves both associate with risk of disease. If 25OHD levels have a causal influence on disease, and DBP lies in this causal pathway, then DBP levels should likewise be causally associated with disease. We undertook a Mendelian randomization study to determine whether DBP levels have causal effects on common calcemic and cardiometabolic disease.

Methods and Findings

We measured DBP and 25OHD levels in 2,254 individuals, followed for up to 10 y, in the Canadian Multicentre Osteoporosis Study (CaMos). Using the single nucleotide polymorphism rs2282679 as an instrumental variable, we applied Mendelian randomization methods to determine the causal effect of DBP on calcemic (osteoporosis and hyperparathyroidism) and cardiometabolic diseases (hypertension, type 2 diabetes, coronary artery disease, and stroke) and related traits, first in CaMos and then in large-scale genome-wide association study consortia. The effect allele was associated with an age- and sex-adjusted decrease in DBP level of 27.4 mg/l (95% CI 24.7, 30.0; n = 2,254). DBP had a strong observational and causal association with 25OHD levels (p = 3.2×10⁻¹⁹). While DBP levels were observationally associated with calcium and body mass index (BMI), these associations were not supported by causal analyses. Despite well-powered sample sizes from consortia, there were no associations of rs2282679 with any other traits and diseases: fasting glucose (0.00 mmol/l [95% CI −0.01, 0.01]; p = 1.00; n = 46,186); fasting insulin (0.01 pmol/l [95% CI −0.00, 0.01,]; p = 0.22; n = 46,186); BMI (0.00 kg/m² [95% CI −0.01, 0.01]; p = 0.80; n = 127,587); bone mineral density (0.01 g/cm² [95% CI −0.01, 0.03]; p = 0.36; n = 32,961); mean arterial pressure (−0.06 mm Hg [95% CI −0.19, 0.07]); p = 0.36; n = 28,775); ischemic stroke (odds ratio [OR] = 1.00 [95% CI 0.97, 1.04]; p = 0.92; n = 12,389/62,004 cases/controls); coronary artery disease (OR = 1.02 [95% CI 0.99, 1.05]; p = 0.31; n = 22,233/64,762); or type 2 diabetes (OR = 1.01 [95% CI 0.97, 1.05]; p = 0.76; n = 9,580/53,810).

Conclusions

DBP has no demonstrable causal effect on any of the diseases or traits investigated here, except 25OHD levels. It remains to be determined whether 25OHD has a causal effect on these outcomes independent of DBP. Please see later in the article for the Editors'' Summary     

Pulmonary and Cardiac Function in Asymptomatic Obese Subjects and Changes following a Structured Weight Reduction Program: A Prospective Observational Study

Background

The prevalence of obesity is rising. Obesity can lead to cardiovascular and ventilatory complications through multiple mechanisms. Cardiac and pulmonary function in asymptomatic subjects and the effect of structured dietary programs on cardiac and pulmonary function is unclear.

Objective

To determine lung and cardiac function in asymptomatic obese adults and to evaluate whether weight loss positively affects functional parameters.

Methods

We prospectively evaluated bodyplethysmographic and echocardiographic data in asymptomatic subjects undergoing a structured one-year weight reduction program.

Results

74 subjects (32 male, 42 female; mean age 42±12 years) with an average BMI 42.5±7.9, body weight 123.7±24.9 kg were enrolled. Body weight correlated negatively with vital capacity (R = −0.42, p<0.001), FEV1 (R = −0.497, p<0.001) and positively with P 0.1 (R = 0.32, p = 0.02) and myocardial mass (R = 0.419, p = 0.002). After 4 months the study subjects had significantly reduced their body weight (−26.0±11.8 kg) and BMI (−8.9±3.8) associated with a significant improvement of lung function (absolute changes: vital capacity +5.5±7.5% pred., p<0.001; FEV1+9.8±8.3% pred., p<0.001, ITGV+16.4±16.0% pred., p<0.001, SR tot −17.4±41.5% pred., p<0.01). Moreover, P0.1/Pimax decreased to 47.7% (p<0.01) indicating a decreased respiratory load. The change of FEV1 correlated significantly with the change of body weight (R = −0.31, p = 0.03). Echocardiography demonstrated reduced myocardial wall thickness (−0.08±0.2 cm, p = 0.02) and improved left ventricular myocardial performance index (−0.16±0.35, p = 0.02). Mitral annular plane systolic excursion (+0.14, p = 0.03) and pulmonary outflow acceleration time (AT +26.65±41.3 ms, p = 0.001) increased.

Conclusion

Even in asymptomatic individuals obesity is associated with abnormalities in pulmonary and cardiac function and increased myocardial mass. All the abnormalities can be reversed by a weight reduction program.     

t-10, c-12 CLA Dietary Supplementation Inhibits Atherosclerotic Lesion Development Despite Adverse Cardiovascular and Hepatic Metabolic Marker Profiles

Animal and human studies have indicated that fatty acids such as the conjugated linoleic acids (CLA) found in milk could potentially alter the risk of developing metabolic disorders including diabetes and cardiovascular disease (CVD). Using susceptible rodent models (apoE^−/− and LDLr^−/− mice) we investigated the interrelationship between mouse strain, dietary conjugated linoleic acids and metabolic markers of CVD. Despite an adverse metabolic risk profile, atherosclerosis (measured directly by lesion area), was significantly reduced with t-10, c-12 CLA and mixed isomer CLA (Mix) supplementation in both apoE^−/− (p<0.05, n = 11) and LDLr^−/− mice (p<0.01, n = 10). Principal component analysis was utilized to delineate the influence of multiple plasma and tissue metabolites on the development of atherosclerosis. Group clustering by dietary supplementation was evident, with the t-10, c-12 CLA supplemented animals having distinct patterns, suggestive of hepatic insulin resistance, regardless of mouse strain. The effect of CLA supplementation on hepatic lipid and fatty acid composition was explored in the LDLr^−/− strain. Dietary supplementation with t-10, c-12 CLA significantly increased liver weight (p<0.05, n = 10), triglyceride (p<0.01, n = 10) and cholesterol ester content (p<0.01, n = 10). Furthermore, t-10, c-12 CLA also increased the ratio of 18∶1 to 18∶0 fatty acid in the liver suggesting an increase in the activity of stearoyl-CoA desaturase. Changes in plasma adiponectin and liver weight with t-10, c-12 CLA supplementation were evident within 3 weeks of initiation of the diet. These observations provide evidence that the individual CLA isomers have divergent mechanisms of action and that t-10, c-12 CLA rapidly changes plasma and liver markers of metabolic syndrome, despite evidence of reduction in atherosclerosis.     

Sequence Variation in DDAH1 and DDAH2 Genes Is Strongly and Additively Associated with Serum ADMA Concentrations in Individuals with Type 2 Diabetes

Background

Asymmetric dimethylarginine (ADMA), present in human serum, is an endogenous inhibitor of nitric oxide synthase and contributes to vascular disease. Dimethylarginine dimethylaminohydrolase (DDAH) is an ADMA degrading enzyme that has two isoforms: DDAHI and DDAHII. We sought to determine whether serum ADMA levels in type 2 diabetes are influenced by common polymorphisms in the DDAH1 and DDAH2 genes.

Methodology/Principal Findings

Relevant clinical parameters were measured and peripheral whole blood obtained for serum and genetic analysis on 343 participants with type 2 diabetes. Serum ADMA concentrations were determined by mass spectroscopy. Twenty six tag SNPs in the DDAH1 and 10 in the DDAH2 gene were genotyped in all subjects and tested for association with serum ADMA levels. Several SNPs and haplotypes in the DDAH genes were strongly associated with ADMA levels. Most significantly in the DDAH1 gene, rs669173 (p = 2.96×10⁻⁷), rs7521189 (p = 6.40×10⁻⁷), rs2474123 (p = 0.00082) and rs13373844 (p = 0.00027), and in the DDAH2 gene, rs3131383 (p = 0.0029) and the TGCCCAGGAG haplotype (p = 0.0012) were significantly associated with ADMA levels. Sub-analysis by diabetic retinopathy (DR) status revealed these variants were associated with ADMA levels predominantly in participants without DR. Combined analysis of the most strongly associated SNPs in DDAH1 (rs669173) and DDAH2 (rs3131383) revealed an additive effect (p = 1.37×10⁻⁸) on ADMA levels.

Conclusions/Significance

Genetic variation in the DDAH1 and 2 genes is significantly associated with serum ADMA levels. Further studies are required to determine the pathophysiological significance of elevated serum ADMA in type 2 diabetes and to better understand how DDAH gene variation influences ADMA levels.     

Selection for Genetic Variation Inducing Pro-Inflammatory Responses under Adverse Environmental Conditions in a Ghanaian Population

Background

Chronic inflammation is involved in the pathogenesis of chronic age-associated, degenerative diseases. Pro-inflammatory host responses that are deleterious later in life may originate from evolutionary selection for genetic variation mediating resistance to infectious diseases under adverse environmental conditions.

Methodology/Principal Findings

In the Upper-East region of Ghana where infection has remained the leading cause of death, we studied the effect on survival of genetic variations at the IL10 gene locus that have been associated with chronic diseases. Here we show that an IL10 haplotype that associated with a pro-inflammatory innate immune response, characterised by low IL-10 (p = 0.028) and high TNF-α levels (p = 1.39×10⁻³), was enriched among Ghanaian elders (p = 2.46×10⁻⁶). Furthermore, in an environment where the source of drinking water (wells/rivers vs. boreholes) influences mortality risks (HR 1.28, 95% CI [1.09–1.50]), we observed that carriers of the pro-inflammatory haplotype have a survival advantage when drinking from wells/rivers but a disadvantage when drinking from boreholes (p_interaction = 0.013). Resequencing the IL10 gene region did not uncover any additional common variants in the pro-inflammatory haplotype to those SNPs that were initially genotyped.

Conclusions/Significance

Altogether, these data lend strong arguments for the selection of pro-inflammatory host responses to overcome fatal infection and promote survival in adverse environments.     

Association between Body Water Status and Acute Mountain Sickness

Purpose

The present study determined the association between body fluid variation and the development of acute mountain sickness (AMS) in adults.

Methods

Forty-three healthy participants (26 males and 17 females, age: 26±6 yr, height: 174±9 cm, weight: 68±12 kg) were passively exposed at a FiO₂ of 12.6% (simulated altitude hypoxia of 4500 m, PiO₂ = 83.9 mmHg) for 12-h. AMS severity was assessed using the Lake Louise Score (LLS). Food and drink intakes were consumed ad libitum and measured; all urine was collected. Before and after the 12-h exposure, body weight and plasma osmolality were measured and whole-body bioimpedance analysis was performed.

Results

The overall AMS incidence was 43% (38% males, 50% females). Participants who developed AMS showed lower fluid losses (3.0±0.9 vs. 4.5±2.0 ml/kg/h, p = 0.002), a higher fluid retention (1.9±1.5 vs. 0.6±0.8 ml/kg/h, p = 0.022), greater plasma osmolality decreases (−7±7 vs. −2±5 mOsm/kg, p = 0.028) and a larger plasma volume expansion (11±10 vs. 1±15%, p = 0.041) compared to participants not developing AMS. Net water balance (fluid intake – fluid loss) and the amount of fluid loss were strong predictors whether getting sick or not (Nagelkerkes r² = 0.532). The LLS score was related to net water balance (r = 0.358, p = 0.018), changes in plasma osmolality (r = −0.325, p = 0.033) and sodium concentration (r = −0.305, p = 0.047). Changes in the impedance vector length were related to weight changes (r = −0.550, p<0.001), fluid intake (r = −0.533, p<0.001) and net water balance (r = −0.590, p<0.001).

Conclusions

Participants developing AMS within 12 hours showed a positive net water balance due to low fluid loss. Thus measures to avoid excess fluid retention are likely to reduce AMS symptoms.     

High-Density SNP Screening of the Major Histocompatibility Complex in Systemic Lupus Erythematosus Demonstrates Strong Evidence for Independent Susceptibility Regions

A substantial genetic contribution to systemic lupus erythematosus (SLE) risk is conferred by major histocompatibility complex (MHC) gene(s) on chromosome 6p21. Previous studies in SLE have lacked statistical power and genetic resolution to fully define MHC influences. We characterized 1,610 Caucasian SLE cases and 1,470 parents for 1,974 MHC SNPs, the highly polymorphic HLA-DRB1 locus, and a panel of ancestry informative markers. Single-marker analyses revealed strong signals for SNPs within several MHC regions, as well as with HLA-DRB1 (global p = 9.99×10⁻¹⁶). The most strongly associated DRB1 alleles were: *0301 (odds ratio, OR = 2.21, p = 2.53×10⁻¹²), *1401 (OR = 0.50, p = 0.0002), and *1501 (OR = 1.39, p = 0.0032). The MHC region SNP demonstrating the strongest evidence of association with SLE was rs3117103, with OR = 2.44 and p = 2.80×10⁻¹³. Conditional haplotype and stepwise logistic regression analyses identified strong evidence for association between SLE and the extended class I, class I, class III, class II, and the extended class II MHC regions. Sequential removal of SLE–associated DRB1 haplotypes revealed independent effects due to variation within OR2H2 (extended class I, rs362521, p = 0.006), CREBL1 (class III, rs8283, p = 0.01), and DQB2 (class II, rs7769979, p = 0.003, and rs10947345, p = 0.0004). Further, conditional haplotype analyses demonstrated that variation within MICB (class I, rs3828903, p = 0.006) also contributes to SLE risk independent of HLA-DRB1*0301. Our results for the first time delineate with high resolution several MHC regions with independent contributions to SLE risk. We provide a list of candidate variants based on biologic and functional considerations that may be causally related to SLE risk and warrant further investigation.     

MR Angiography,MR Imaging and Proton MR Spectroscopy In-Vivo Assessment of Skeletal Muscle Ischemia in Diabetic Rats

To prospectively evaluate the feasibility of using magnetic resonance (MR) techniques for in-vivo assessing a rat diabetic model of limb ischemia. Unilateral hind limb ischemia was induced by ligation of the iliac-femoral artery in male streptozotocin-treated and non-diabetic control rats. Four weeks after ligation, rats underwent MR Angiography (MRA), T₁-weighted and Short Time Inversion Recovery (STIR) sequences and muscle Proton MR Spectroscopy (¹H-MRS) on both hind limbs. After MR examinations, immunoblotting and immunofluorescence analysis were performed. MRA showed a signal void due to flow discontinuation distal to the artery ligation. T₁-weighted and STIR images showed, respectively, the presence of tissue swelling (p = 0.018 for non-diabetic; p = 0.027 for diabetic rats) and signal hyperintensity in tissue affected by occlusion. Mean total creatine/water for the occluded limb was significantly lower than for the non-occluded limbs in both non-diabetic (5.46×10⁻⁴ vs 1.14×10⁻³, p = 0.028) and diabetic rats (1.37×10⁻⁴ vs 1.10×10⁻³; p = 0.018). MR Imaging and ¹H-MRS changes were more pronounced in diabetic than in non-diabetic occluded limbs (p = 0.032). MR findings were confirmed by using histological findings. Combined MR techniques can be used to demonstrate the presence of structural and metabolic changes produced by iliac-femoral artery occlusion in rat diabetic model of limb ischemia.