Hepatitis C Virus Induces the Cannabinoid Receptor 1

Background

Activation of hepatic CB₁ receptors (CB₁) is associated with steatosis and fibrosis in experimental forms of liver disease. However, CB₁ expression has not been assessed in patients with chronic hepatitis C (CHC), a disease associated with insulin resistance, steatosis and metabolic disturbance. We aimed to determine the importance and explore the associations of CB₁ expression in CHC.

Methods

CB₁ receptor mRNA was measured by real time quantitative PCR on extracted liver tissue from 88 patients with CHC (genotypes 1 and 3), 12 controls and 10 patients with chronic hepatitis B (CHB). The Huh7/JFH1 Hepatitis C virus (HCV) cell culture model was used to validate results.

Principal Findings

CB₁ was expressed in all patients with CHC and levels were 6-fold higher than in controls (P<0.001). CB₁ expression increased with fibrosis stage, with cirrhotics having up to a 2 fold up-regulation compared to those with low fibrosis stage (p<0.05). Even in mild CHC with no steatosis (F0-1), CB₁ levels remained substantially greater than in controls (p<0.001) and in those with mild CHB (F0-1; p<0.001). Huh7 cells infected with JFH-1 HCV showed an 8-fold upregulation of CB₁, and CB₁ expression directly correlated with the percentage of cells infected over time, suggesting that CB₁ is an HCV inducible gene. While HCV structural proteins appear essential for CB₁ induction, there was no core genotype specific difference in CB₁ expression. CB₁ significantly increased with steatosis grade, primarily driven by patients with genotype 3 CHC. In genotype 3 patients, CB₁ correlated with SREBP-1c and its downstream target FASN (SREBP-1c; R = 0.37, FASN; R = 0.39, p<0.05 for both).

Conclusions/Significance

CB₁ is up-regulated in CHC and is associated with increased steatosis in genotype 3. It is induced by the hepatitis C virus.     

Monitoring Lung Aeration during Respiratory Support in Preterm Infants at Birth

Background

If infants fail to initiate spontaneous breathing, resuscitation guidelines recommend respiratory support with positive pressure ventilation (PPV). The purpose of PPV is to establish functional residual capacity and deliver an adequate tidal volume (V_T) to achieve gas exchange.

Objective

The aim of our pilot study was to measure changes in exhaled carbon dioxide (ECO₂), V_T, and rate of carbon dioxide elimination (VCO₂) to assess lung aeration in preterm infants requiring respiratory support immediately after birth.

Method

A prospective observational study was performed between March and July 2013. Infants born at <37 weeks gestational age who received continuous positive airway pressure (CPAP) or PPV immediately after birth had V_T delivery and ECO₂ continuously recorded using a sensor attached to the facemask.

Results

Fifty-one preterm infants (mean (SD) gestational age 29 (3) weeks and birth weight 1425 (592 g)) receiving respiratory support in the delivery room were included. Infants in the CPAP group (n = 31) had higher ECO₂ values during the first 10 min after birth compared to infants receiving PPV (n = 20) (ranging between 18–30 vs. 13–18 mmHg, p<0.05, respectively). At 10 min no significant difference in ECO₂ values was observed. V_T was lower in the CPAP group compared to the PPV group over the first 10 min ranging between 5.2–6.6 vs. and 7.2–11.3 mL/kg (p<0.05), respectively.

Conclusions

Immediately after birth, spontaneously breathing preterm infants supported via CPAP achieved better lung aeration compared to infants requiring PPV. PPV guided by V_T and ECO₂ potentially optimize lung aeration without excessive V_T administered.     

Longitudinal,Lateral and Transverse Axes of Forearm Muscles Influence the Crosstalk in the Mechanomyographic Signals during Isometric Wrist Postures

Problem Statement

In mechanomyography (MMG), crosstalk refers to the contamination of the signal from the muscle of interest by the signal from another muscle or muscle group that is in close proximity.

Purpose

The aim of the present study was two-fold: i) to quantify the level of crosstalk in the mechanomyographic (MMG) signals from the longitudinal (L_o), lateral (L_a) and transverse (T_r) axes of the extensor digitorum (ED), extensor carpi ulnaris (ECU) and flexor carpi ulnaris (FCU) muscles during isometric wrist flexion (WF) and extension (WE), radial (RD) and ulnar (UD) deviations; and ii) to analyze whether the three-directional MMG signals influence the level of crosstalk between the muscle groups during these wrist postures.

Methods

Twenty, healthy right-handed men (mean ± SD: age = 26.7±3.83 y; height = 174.47±6.3 cm; mass = 72.79±14.36 kg) participated in this study. During each wrist posture, the MMG signals propagated through the axes of the muscles were detected using three separate tri-axial accelerometers. The x-axis, y-axis, and z-axis of the sensor were placed in the L_o, L_a, and T_r directions with respect to muscle fibers. The peak cross-correlations were used to quantify the proportion of crosstalk between the different muscle groups.

Results

The average level of crosstalk in the MMG signals generated by the muscle groups ranged from: 34.28–69.69% for the L_o axis, 27.32–52.55% for the L_a axis and 11.38–25.55% for the T_r axis for all participants and their wrist postures. The T_r axes between the muscle groups showed significantly smaller crosstalk values for all wrist postures [F (2, 38) = 14–63, p<0.05, η ² = 0.416–0.769].

Significance

The results may be applied in the field of human movement research, especially for the examination of muscle mechanics during various types of the wrist postures.     

Bandoniozyma gen. nov., a Genus of Fermentative and Non-Fermentative Tremellaceous Yeast Species

Background

Independent surveys across the globe led to the proposal of a new basidiomycetous yeast genus within the Bulleromyces clade of the Tremellales, Bandoniozyma gen. nov., with seven new species.

Methodology/Principal Findings

The species were characterized by multiple methods, including the analysis of D1/D2 and ITS nucleotide sequences, and morphological and physiological/biochemical traits. Most species can ferment glucose, which is an unusual trait among basidiomycetous yeasts.

Conclusions/Significance

In this study we propose the new yeast genus Bandoniozyma, with seven species Bandoniozyma noutii sp. nov. (type species of genus; CBS 8364^T  =  DBVPG 4489^T), Bandoniozyma aquatica sp. nov. (UFMG-DH4.20^T  =  CBS 12527^T  =  ATCC MYA-4876^T), Bandoniozyma complexa sp. nov. (CBS 11570^T  =  ATCC MYA-4603^T  =  MA28a^T), Bandoniozyma fermentans sp. nov. (CBS 12399^T  =  NU7M71^T  =  BCRC 23267^T), Bandoniozyma glucofermentans sp. nov. (CBS 10381^T  =  NRRL Y-48076^T  =  ATCC MYA-4760^T  =  BG 02-7-15-015A-1-1^T), Bandoniozyma tunnelae sp. nov. (CBS 8024^T  =  DBVPG 7000^T), and Bandoniozyma visegradensis sp. nov. (CBS 12505^T  =  NRRL Y-48783^T  =  NCAIM Y.01952^T).     

Altered Plasma Apolipoprotein Modifications in Patients with Pancreatic Cancer: Protein Characterization and Multi-Institutional Validation

Background

Among the more common human malignancies, invasive ductal carcinoma of the pancreas has the worst prognosis. The poor outcome seems to be attributable to difficulty in early detection.

Methods

We compared the plasma protein profiles of 112 pancreatic cancer patients with those of 103 sex- and age-matched healthy controls (Cohort 1) using a newly developed matrix-assisted laser desorption/ionization (oMALDI) QqTOF (quadrupole time-of-flight) mass spectrometry (MS) system.

Results

We found that hemi-truncated apolipoprotein AII dimer (ApoAII-2; 17252 m/z), unglycosylated apolipoprotein CIII (ApoCIII-0; 8766 m/z), and their summed value were significantly decreased in the pancreatic cancer patients [P = 1.36×10⁻²¹, P = 4.35×10⁻¹⁴, and P = 1.83×10⁻²⁴ (Mann-Whitney U-test); area-under-curve values of 0.877, 0.798, and 0.903, respectively]. The significance was further validated in a total of 1099 plasma/serum samples, consisting of 2 retrospective cohorts [Cohort 2 (n = 103) and Cohort 3 (n = 163)] and a prospective cohort [Cohort 4 (n = 833)] collected from 8 medical institutions in Japan and Germany.

Conclusions

We have constructed a robust quantitative MS profiling system and used it to validate alterations of modified apolipoproteins in multiple cohorts of patients with pancreatic cancer.     

Apoptosis of CD4+CD25high T Cells in Type 1 Diabetes May Be Partially Mediated by IL-2 Deprivation

Background

Type 1 diabetes (T1D) is a T-cell mediated autoimmune disease targeting the insulin-producing pancreatic β cells. Naturally occurring FOXP3⁺CD4⁺CD25^high regulatory T cells (T_regs) play an important role in dominant tolerance, suppressing autoreactive CD4⁺ effector T cell activity. Previously, in both recent-onset T1D patients and β cell antibody-positive at-risk individuals, we observed increased apoptosis and decreased function of polyclonal T_regs in the periphery. Our objective here was to elucidate the genes and signaling pathways triggering apoptosis in T_regs from T1D subjects.

Principal Findings

Gene expression profiles of unstimulated T_regs from recent-onset T1D (n = 12) and healthy control subjects (n = 15) were generated. Statistical analysis was performed using a Bayesian approach that is highly efficient in determining differentially expressed genes with low number of replicate samples in each of the two phenotypic groups. Microarray analysis showed that several cytokine/chemokine receptor genes, HLA genes, GIMAP family genes and cell adhesion genes were downregulated in T_regs from T1D subjects, relative to control subjects. Several downstream target genes of the AKT and p53 pathways were also upregulated in T1D subjects, relative to controls. Further, expression signatures and increased apoptosis in T_regs from T1D subjects partially mirrored the response of healthy T_regs under conditions of IL-2 deprivation. CD4⁺ effector T-cells from T1D subjects showed a marked reduction in IL-2 secretion. This could indicate that prior to and during the onset of disease, T_regs in T1D may be caught up in a relatively deficient cytokine milieu.

Conclusions

In summary, expression signatures in T_regs from T1D subjects reflect a cellular response that leads to increased sensitivity to apoptosis, partially due to cytokine deprivation. Further characterization of these signaling cascades should enable the detection of genes that can be targeted for restoring T_reg function in subjects predisposed to T1D.     

A Large Scale Gene-Centric Association Study of Lung Function in Newly-Hired Female Cotton Textile Workers with Endotoxin Exposure

Background

Occupational exposure to endotoxin is associated with decrements in pulmonary function, but how much variation in this association is explained by genetic variants is not well understood.

Objective

We aimed to identify single nucleotide polymorphisms (SNPs) that are associated with the rate of forced expiratory volume in one second (FEV₁) decline by a large scale genetic association study in newly-hired healthy young female cotton textile workers.

Methods

DNA samples were genotyped using the Illumina Human CVD BeadChip. Change rate in FEV₁ was modeled as a function of each SNP genotype in linear regression model with covariate adjustment. We controlled the type 1 error in study-wide level by permutation method. The false discovery rate (FDR) and the family-wise error rate (FWER) were set to be 0.10 and 0.15 respectively.

Results

Two SNPs were found to be significant (P<6.29×10⁻⁵), including rs1910047 (P = 3.07×10⁻⁵, FDR = 0.0778) and rs9469089 (P = 6.19×10⁻⁵, FDR = 0.0967), as well as other eight suggestive (P<5×10⁻⁴) associated SNPs. Gene-gene and gene-environment interactions were also observed, such as rs1910047 and rs1049970 (P = 0.0418, FDR = 0.0895); rs9469089 and age (P = 0.0161, FDR = 0.0264). Genetic risk score analysis showed that the more risk loci the subjects carried, the larger the rate of FEV₁ decline occurred (P _trend = 3.01×10⁻¹⁸). However, the association was different among age subgroups (P = 7.11×10⁻⁶) and endotoxin subgroups (P = 1.08×10⁻²). Functional network analysis illustrates potential biological connections of all interacted genes.

Conclusions

Genetic variants together with environmental factors interact to affect the rate of FEV₁ decline in cotton textile workers.     

Vascular Endothelial Growth Factor Genotypes and Haplotypes Contribute to the Susceptibility of Obstructive Sleep Apnea Syndrome

Background

To investigate whether VEGF polymorphisms (-460T/C, +405G/C, and +936C/T)/haplotypes influence the susceptibility of obstructive sleep apnea (OSA).

Method

A prospective case-control study was conducted to evaluate the genetic effects of VEGF polymorphisms on the development of OSA. 150 patients and 225 healthy controls were recruited for this study and their genotypes were determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). The odds ratios (OR) and 95% confidence intervals (CI) were calculated by logistic regression analysis.

Result

Our study showed that the -460C allele (C vs. T: OR = 1.95, 95% CI = 1.38–2.76) and +936T allele (T vs. C: OR = 1.48, 95% CI = 1.02–2.15) were associated with an increased OSA risk, whereas +405C allele was associated with a decreased susceptibility to OSA (C vs. G: OR = 0.61, 95% CI = 0.45–0.83). Compared with the most common haplotype CCT, CGC (OR = 2.22, 95% CI = 1.19–4.13) and TGC (OR = 3.83, 95% CI = 1.56–9.40) were associated with a significantly increased risk of OSA.

Conclusion

These observations implied that VEGF gene polymorphisms might be associated with the susceptibility to OSA. These results need to be validated by other independent studies, especially in diverse ethnic populations.     

Pathological Mechanism for Delayed Hyperenhancement of Chronic Scarred Myocardium in Contrast Agent Enhanced Magnetic Resonance Imaging

Objectives

To evaluate possible mechanism for delayed hyperenhancement of scarred myocardium by investigating the relationship of contrast agent (CA) first pass and delayed enhancement patterns with histopathological changes.

Materials and Methods

Eighteen pigs underwent 4 weeks ligation of 1 or 2 diagonal coronary arteries to induce chronic infarction. The hearts were then removed and perfused in a Langendorff apparatus. The hearts firstly experienced phosphorus 31 MR spectroscopy. The hearts in group I (n = 9) and II (n = 9) then received the bolus injection of Gadolinium diethylenetriamine pentaacetic acid (0.05 mmol/kg) and gadolinium-based macromolecular agent (P792, 15 µmol/kg), respectively. First pass T₂ ^* MRI was acquired using a gradient echo sequence. Delayed enhanced T₁ MRI was acquired with an inversion recovery sequence. Masson''s trichrome and anti- von Willebrand Factor (vWF) staining were performed for infarct characterization.

Results

Wash-in of both kinds of CA caused the sharp and dramatic T₂ ^* signal decrease of scarred myocardium similar to that of normal myocardium. Myocardial blood flow and microvessel density were significantly recovered in 4-week-old scar tissue. Steady state distribution volume (ΔR₁ relaxation rate) of Gd-DTPA was markedly higher in scarred myocardium than in normal myocardium, whereas ΔR₁ relaxation rate of P792 did not differ significantly between scarred and normal myocardium. The ratio of extracellular volume to the total water volume was significantly greater in scarred myocardium than in normal myocardium. Scarred myocardium contained massive residual capillaries and dilated vessels. Histological stains indicated the extensively discrete matrix deposition and lack of cellular structure in scarred myocardium.

Conclusions

Collateral circulation formation and residual vessel effectively delivered CA into scarred myocardium. However, residual vessel without abnormal hyperpermeability allowed Gd-DTPA rather than P792 to penetrate into extravascular compartment. Discrete collagen fiber meshwork and loss of cellularity enlarged extracellular space accessible to Gd-DTPA, resulting in the delayed hyper-enhanced scar.     

Genome-Wide Association Studies of Asthma in Population-Based Cohorts Confirm Known and Suggested Loci and Identify an Additional Association near HLA

Rationale

Asthma has substantial morbidity and mortality and a strong genetic component, but identification of genetic risk factors is limited by availability of suitable studies.

Objectives

To test if population-based cohorts with self-reported physician-diagnosed asthma and genome-wide association (GWA) data could be used to validate known associations with asthma and identify novel associations.

Methods

The APCAT (Analysis in Population-based Cohorts of Asthma Traits) consortium consists of 1,716 individuals with asthma and 16,888 healthy controls from six European-descent population-based cohorts. We examined associations in APCAT of thirteen variants previously reported as genome-wide significant (P<5x10⁻⁸) and three variants reported as suggestive (P<5×10⁻⁷). We also searched for novel associations in APCAT (Stage 1) and followed-up the most promising variants in 4,035 asthmatics and 11,251 healthy controls (Stage 2). Finally, we conducted the first genome-wide screen for interactions with smoking or hay fever.

Main Results

We observed association in the same direction for all thirteen previously reported variants and nominally replicated ten of them. One variant that was previously suggestive, rs11071559 in RORA, now reaches genome-wide significance when combined with our data (P = 2.4×10⁻⁹). We also identified two genome-wide significant associations: rs13408661 near IL1RL1/IL18R1 (P _{Stage1+Stage2} = 1.1x10⁻⁹), which is correlated with a variant recently shown to be associated with asthma (rs3771180), and rs9268516 in the HLA region (P _{Stage1+Stage2} = 1.1x10⁻⁸), which appears to be independent of previously reported associations in this locus. Finally, we found no strong evidence for gene-environment interactions with smoking or hay fever status.

Conclusions

Population-based cohorts with simple asthma phenotypes represent a valuable and largely untapped resource for genetic studies of asthma.     

Protective Ventilation of Preterm Lambs Exposed to Acute Chorioamnionitis Does Not Reduce Ventilation-Induced Lung or Brain Injury

Background

The onset of mechanical ventilation is a critical time for the initiation of cerebral white matter (WM) injury in preterm neonates, particularly if they are inadvertently exposed to high tidal volumes (V_T) in the delivery room. Protective ventilation strategies at birth reduce ventilation-induced lung and brain inflammation and injury, however its efficacy in a compromised newborn is not known. Chorioamnionitis is a common antecedent of preterm birth, and increases the risk and severity of WM injury. We investigated the effects of high V_T ventilation, after chorioamnionitis, on preterm lung and WM inflammation and injury, and whether a protective ventilation strategy could mitigate the response.

Methods

Pregnant ewes (n = 18) received intra-amniotic lipopolysaccharide (LPS) 2 days before delivery, instrumentation and ventilation at 127±1 days gestation. Lambs were either immediately euthanased and used as unventilated controls (LPS_UVC; n = 6), or were ventilated using an injurious high V_T strategy (LPS_INJ; n = 5) or a protective ventilation strategy (LPS_PROT; n = 7) for a total of 90 min. Mean arterial pressure, heart rate and cerebral haemodynamics and oxygenation were measured continuously. Lungs and brains underwent molecular and histological assessment of inflammation and injury.

Results

LPS_INJ lambs had poorer oxygenation than LPS_PROT lambs. Ventilation requirements and cardiopulmonary and systemic haemodynamics were not different between ventilation strategies. Compared to unventilated lambs, LPS_INJ and LPS_PROT lambs had increases in pro-inflammatory cytokine expression within the lungs and brain, and increased astrogliosis (p<0.02) and cell death (p<0.05) in the WM, which were equivalent in magnitude between groups.

Conclusions

Ventilation after acute chorioamnionitis, irrespective of strategy used, increases haemodynamic instability and lung and cerebral inflammation and injury. Mechanical ventilation is a potential contributor to WM injury in infants exposed to chorioamnionitis.     

Spatial Characterization of Electrogram Morphology from Transmural Recordings in the Intact Normal Heart

Purpose

Unipolar (UE) and bipolar electrograms (BE) are utilized to identify arrhythmogenic substrate. We quantified the effect of increasing distance from the source of propagation on local electrogram amplitude; and determined if transmural electrophysiological gradients exist with respect to propagation and stimulation depth.

Methods

Mapping was performed on 5 sheep. Deployment of >50 quadripolar transmural needles in the LV were located in Cartesian space using Ensite. Contact electrograms from all needles were recorded during multisite bipolar pacing from epicardial then endocardial electrodes. Analysis was performed to determine stimulus distance to local activation time, peak negative amplitude (V_-P), and peak-peak amplitude (V_P-P) for (1) unfiltered UE, and (2) unfiltered and 30 Hz high-pass filtered BEs. Each sheep was analysed using repeated ANOVA.

Results

Increasing distance from the pacing sites led to significant (p<0.01) attenuation of UEs (V_-P = 7.0±0.5%; V_P-P = 5.4±0.3% per cm). Attenuation of BE with distance was insignificant (V_p-p unfiltered  = 2.2±0.5%; filtered  = 1.7±1.4% per cm). Independent of pacing depth, significant (p<0.01) transmural electrophysiological gradients were observed, with highest amplitude occurring at epicardial layers for UE and endocardial layers for BE. Furthermore, during pacing, propagation was earlier at the epicardium than endocardial layer by 1.6±2.0 ms (UE) and 1.4±2.8 ms (BE) (all p>0.01) during endocardial stimulation, and 2.3±2.4 ms (UE) and 1.8±3.7 ms (BE) during epicardal stimulation (all p<0.01).

Conclusions

Electrogram amplitude is inversely proportional to propagation distance for unipolar modalities only, which affected V_-P>V_P-P. Conduction propagates preferentially via the epicardium during stimulation and is believed to contribute to a transmural amplitude gradient.     

IL-4 Haplotype -590T, -34T and Intron-3 VNTR R2 Is Associated with Reduced Malaria Risk among Ancestral Indian Tribal Populations

Background

Interleukin 4 (IL-4) is an anti-inflammatory cytokine, which regulates balance between T_H1 and T_H2 immune response, immunoglobulin class switching and humoral immunity. Polymorphisms in this gene have been reported to affect the risk of infectious and autoimmune diseases.

Methods

We have analyzed three regulatory IL-4 polymorphisms; -590C>T, -34C>T and 70 bp intron-3 VNTR, in 4216 individuals; including: (1) 430 ethnically matched case-control groups (173 severe malaria, 101 mild malaria and 156 asymptomatic); (2) 3452 individuals from 76 linguistically and geographically distinct endogamous populations of India, and (3) 334 individuals with different ancestry from outside India (84 Brazilian, 104 Syrian, and 146 Vietnamese).

Results

The -590T, -34T and intron-3 VNTR R2 alleles were found to be associated with reduced malaria risk (P<0.001 for -590C>T and -34C>T, and P = 0.003 for VNTR). These three alleles were in strong LD (r²>0.75) and the TTR2 (-590T, -34T and intron-3 VNTR R2) haplotype appeared to be a susceptibility factor for malaria (P = 0.009, OR = 0.552, 95% CI = 0.356 –0.854). Allele and genotype frequencies differ significantly between caste, nomadic, tribe and ancestral tribal populations (ATP). The distribution of protective haplotype TTR2 was found to be significant (χ² ₃ = 182.95, p-value <0.001), which is highest in ATP (40.5%); intermediate in tribes (33%); and lowest in caste (17.8%) and nomadic (21.6%).

Conclusions

Our study suggests that the IL-4 polymorphisms regulate host susceptibility to malaria and disease progression. TTR2 haplotype, which gives protection against malaria, is high among ATPs. Since they inhabited in isolation and mainly practice hunter-gatherer lifestyles and exposed to various parasites, IL-4 TTR2 haplotype might be under positive selection.     

Accuracy of Specific BIVA for the Assessment of Body Composition in the United States Population

Background

Bioelectrical impedance vector analysis (BIVA) is a technique for the assessment of hydration and nutritional status, used in the clinical practice. Specific BIVA is an analytical variant, recently proposed for the Italian elderly population, that adjusts bioelectrical values for body geometry.

Objective

Evaluating the accuracy of specific BIVA in the adult U.S. population, compared to the ‘classic’ BIVA procedure, using DXA as the reference technique, in order to obtain an interpretative model of body composition.

Design

A cross-sectional sample of 1590 adult individuals (836 men and 754 women, 21–49 years old) derived from the NHANES 2003–2004 was considered. Classic and specific BIVA were applied. The sensitivity and specificity in recognizing individuals below the 5^th and above the 95^th percentiles of percent fat (FM_DXA%) and extracellular/intracellular water (ECW/ICW) ratio were evaluated by receiver operating characteristic (ROC) curves. Classic and specific BIVA results were compared by a probit multiple-regression.

Results

Specific BIVA was significantly more accurate than classic BIVA in evaluating FM_DXA% (ROC areas: 0.84–0.92 and 0.49–0.61 respectively; p = 0.002). The evaluation of ECW/ICW was accurate (ROC areas between 0.83 and 0.96) and similarly performed by the two procedures (p = 0.829). The accuracy of specific BIVA was similar in the two sexes (p = 0.144) and in FM_DXA% and ECW/ICW (p = 0.869).

Conclusions

Specific BIVA showed to be an accurate technique. The tolerance ellipses of specific BIVA can be used for evaluating FM% and ECW/ICW in the U.S. adult population.     

Impairment of Myocardial Mitochondria in Viral Myocardial Disease and Its Reflective Window in Peripheral Cells

Background

Viral myocardial disease (VMD) is a common disease inducing heart failure. It has not been clear the roles of mitochondrial damage in the pathological changes of cardiomyocytes in VMD.

Methods

Myocardial tissues and lymphocytes were collected from 83 VMD patients. Control groups included 12 cases of healthy accidental death with myocardial autopsy and 23 healthy blood donors. The mouse model of viral myocarditis (VMC) was established by Coxsackie virus B₃ infection and myocardial tissues and skeletal muscle were collected. Mitochondrial DNA (mtDNA) deletion rate was quantitatively determined using polymerase chain reaction.

Results

There was significantly difference of myocardial mitochondrial DNA deletion rate between VMD or VMC group and control group (P<0.05). Moreover, the loss of mitochondrial membrane phospholipids was significantly different between VMD or VMC group and control group. In VMC mice, there were negative correlations between myocardial mtDNA³⁸⁶⁷ deletion rate and left ventricular peak systolic pressure (LVPSP) (r = −0.66, P<0.05), and between myocardial mtDNA³⁸⁶⁷ deletion rate and +dp/dt_max (r = −0.79, P<0.05), while there was positive correlation between myocardial mtDNA³⁸⁶⁷ deletion rate and −dp/dt_max (r = 0.80, P<0.05).

Conclusion

Mitochondrial damage is an important pathophysiological mechanism leading to myocardial injury and cardiac dysfunction. The mitochondrial damage in the skeletal muscle and lymphocytes reflect a “window” of myocardial mitochondrial damage.     

A Functional Variant of PTPN22 Confers Risk for Vogt-Koyanagi-Harada Syndrome but Not for Ankylosing Spondylitis

Background

Protein tyrosine phosphatase non-receptor 22 (PTPN22) is a key negative regulator of T lymphocytes and has emerged as an important candidate susceptibility factor for a number of immune-related diseases. This study aimed to examine the predisposition of PTPN22 SNPs to Vogt-Koyanagi-Harada (VKH) syndrome and acute anterior uveitis (AAU) associated with ankylosing spondylitis (AS).

Methods

A total of 1005 VKH syndrome, 302 AAU⁺AS⁺ patients and 2010 normal controls among the Chinese Han population were enrolled in the study. Genotyping, PTPN22 expression, cell proliferation, cytokine production and cell activation were examined by PCR-RFLP, Real-time PCR, CCK8, ELISA and Flow cytometry.

Results

The results showed significantly increased frequencies of the rs2488457 CC genotype and C allele but a decreased frequency of the GG genotype in VKH syndrome patients (P_{Bonferroni correction} (P_c) = 3.47×10⁻⁷, OR = 1.54; P_c = 3.83×10⁻⁸, OR = 1.40; P_c = 6.35×10⁻⁴, OR = 0.62; respectively). No significant association of the tested SNPs with AAU⁺AS⁺ patients was observed. Functional studies showed a decreased PTPN22 expression, impaired cell proliferation and lower production of IL-10 in rs2488457 CC cases compared to GG cases (P_c = 0.009, P_c = 0.015 and P_c = 0.048 respectively). No significant association was observed concerning T cell activation and rs2488457 genotype.

Conclusions

The study showed that a functional variant of PTPN22 confers risk for VKH syndrome but not for AAU⁺AS⁺ in a Chinese Han population, which may be due to a modulation of the PTPN22 expression, PBMC proliferation and IL-10 production.     

Determinants and Improvement of Electrocardiographic Diagnosis of Left Ventricular Hypertrophy in a Black African Population

Background

Left ventricular hypertrophy (LVH) is a major cardiovascular risk factor. The electrocardiogram (ECG) has been shown to be a poor tool in detecting LVH due to cardiac and extracardiac factors. We studied the determinants and possibility of improving the test performance of the ECG in a group of Black Africans.

Methods

We studied echocardiograms and electrocardiograms of 182 Cameroonian patients among whom 113 (62.1%) were having an echocardiographic LVH. Echocardiographic LVH was defined as Left Ventricular Mass Indexed to height ^2.7(LVMI)>48 g/m^2.7 in men, and >44 g/m ^2.7 in women or Body Surface Area ≥116 g/m² in men, and ≥96 g/m² in women. Test performances were calculated for 6 classic ECG criteria Sokolow-Lyon, Cornell, Cornell product, Gubner-Ungerleiger, amplitudes of R in aVL, V₅ and V₆.

Results

The most sensitive criteria were Cornell (37.2%) and Sokolow-Lyon index (26.5%). The most specific criteria were Gubner (98.6%), RaVL (97.1%), RV₅/V₆ (95.7%) and Cornell product (94.2%). The performance of the ECG in diagnosing LVH significantly increased with the severity of LVH for Cornell index (r = 0.420, p<0.0001) and Sokolow index (r = 0.212, p = 0.002). It decreased with body habitus (r = −0.248, p = 0.001) for Sokolow-Lyon index. Cornell index was less affected (age p = 0.766; body habitus: p = 0.209). After sex-specific adjustment for BMI, Cornell BMI sensitivity increased from 37.2% to 69% (r = 0.472, p<0.0001), and Sokolow-Lyon BMI sensitivity increased from 26.5% to 58.4% (r = 0.270, p<0.001).

Conclusion

The test performance of the ECG in diagnosing LVH is low in this Black African population, due to extracardiac factors such as age, sex, body habitus, and cardiac factors such as LVH severity and geometry. However, this performance is improved after adjustment for extracardiac factors.     

Genetic Variations of IL-12B,IL-12Rβ1, IL-12Rβ2 in Behcet's Disease and VKH Syndrome

Purpose

To investigate the associations of single nucleotide polymorphisms (SNPs) of three genes (IL-12B, IL-12Rβ1 and IL-12Rβ2) in Behcet''s disease (BD) and Vogt-Koyanagi-Harada (VKH) syndrome in a Chinese Han population.

Methods

A total of 806 BD cases, 820 VKH patients, and 1600 healthy controls were involved in this study. The first investigation included 400 BD patients, 400 VKH cases, and 600 healthy individuals. A second confirmatory study included a separate set of 406 BD patients, 420 VKH cases and another 1000 normal controls. Genotyping was carried out by PCR-restriction fragment length polymorphism assay and results were validated by using direct sequencing. The χ2 test was performed to compare the allele and genotype frequencies between cases and healthy controls.

Results

This study comprised two phases. In the first phase study, a significantly increased frequency of the rs3212227/IL-12B genotype CC and C allele was found in BD patients as compared to controls (Bonferroni corrected p value (p_c) = 0.009, OR 1.8; p_c = 0.024, OR 1.3, respectively). Moreover, the frequency of the C allele of rs3212227/IL-12B was also significantly increased in VKH patients (p_c = 0.012, OR 1.3, 95% CI 1.1 to 1.6). No associations were found for the other seven tested SNPs either in BD or VKH disease. The second study as well as the combined data confirmed the significant association of rs3212227/IL-12B with BD (CC genotype: combined p_c = 6.3×10⁻⁷, OR = 1.8; C allele: combined p_c = 2.0×10⁻⁵, OR = 1.3, respectively) and the C allele frequency of rs3212227/IL-12B as the risk factor to VKH patients (combined p_c = 2.5×10⁻⁵, OR 1.3, 95% CI 1.2 to 1.5).

Conclusions

Our study revealed that the IL-12B gene is involved both in the susceptibility to BD as well as VKH syndrome.     

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.     

Amiodarone Inhibits Apamin-Sensitive Potassium Currents

Background

Apamin sensitive potassium current (I _KAS), carried by the type 2 small conductance Ca²⁺-activated potassium (SK2) channels, plays an important role in post-shock action potential duration (APD) shortening and recurrent spontaneous ventricular fibrillation (VF) in failing ventricles.

Objective

To test the hypothesis that amiodarone inhibits I _KAS in human embryonic kidney 293 (HEK-293) cells.

Methods

We used the patch-clamp technique to study I _KAS in HEK-293 cells transiently expressing human SK2 before and after amiodarone administration.

Results

Amiodarone inhibited I_KAS in a dose-dependent manner (IC₅₀, 2.67±0.25 µM with 1 µM intrapipette Ca²⁺). Maximal inhibition was observed with 50 µM amiodarone which inhibited 85.6±3.1% of I_KAS induced with 1 µM intrapipette Ca²⁺ (n = 3). I_KAS inhibition by amiodarone was not voltage-dependent, but was Ca²⁺-dependent: 30 µM amiodarone inhibited 81.5±1.9% of I _KAS induced with 1 µM Ca²⁺ (n = 4), and 16.4±4.9% with 250 nM Ca²⁺ (n = 5). Desethylamiodarone, a major metabolite of amiodarone, also exerts voltage-independent but Ca²⁺ dependent inhibition of I _KAS.

Conclusion

Both amiodarone and desethylamiodarone inhibit I _KAS at therapeutic concentrations. The inhibition is independent of time and voltage, but is dependent on the intracellular Ca²⁺ concentration. SK2 current inhibition may in part underlie amiodarone''s effects in preventing electrical storm in failing ventricles.