High JAK2V617F allele burden is associated with an increased burden of coronary artery calcification in MPNs

Background

Patients with the haematological cancers Philadelphia-negative Myeloproliferative Neoplasms (MPNs), have an increased risk of coronary artery and aortic valve calcification, and an increased risk of myocardial infarctions. The most common acquired mutation in MPNs, the JAK2V617F mutation, has been linked to increased risk of thrombosis.

Aims

To exam the association between the JAK2V617F mutation, its allele burden, and coronary artery and aortic valve calcification.

Methods

One hundred and sixty one patients with MPN disease from one specialized haematological outpatient clinic where included. Information on demographics, smoking, alcohol habits and co-morbidities were registered. Blood samples were drawn for determination of the JAK2V617 mutation and allele burden. Patients were examined by cardiac computer tomography in order to determine their coronary artery calcium score (CACS) and aortic valve calcification (AVC) score. The association between the JAK2V617F mutation, its allele burden and coronary artery and aortic calcification was investigated with univariate and multivariate logistic regression analysis, adjusting for age, sex, ischemic heart disease (IHD), stroke, smoking, obesity, hypertension, hypercholesterolemia, diabetes mellitus, and family history of IHD or stroke in the multivariate analysis.

Results

Of the 161 patients (52% male, mean age 65.5±10.5 years), 137 (85%) were JAK2V617F positives, and the JAK2V617F allele burden was quantified in 120. The median JAK2V617F allele burden was 12% (IQR range 6–33%). There were 42 (26%) patients with a CACS >400, and 93 (58%) patients AVC. Among the JAK2V617F positive patients, 38 (24%) had a CACS >400 and 81 (59%) had AVC. In the 32 patients with a JAK2V617F allele burden>33%, 19 (59%) had a CACS >400 and 26 (81%) had AVC. In the univariate logistic regression analysis the presence of JAK2V617F mutation was not associated with a CACS >400 (Odds Ratio (OR) 1.92, 95% confidence interval (CI) 0.62–5.98, p=0.26). Similar result was found for the analysis on AVC (OR 1.45, 95% CI 0.61–3.45, p=0.41). In contrast, a JAK2V617F allele burden >33% was significantly associated with a CACS >400 (OR 5.31, 95% CI 2.23–12.66, p=0.0002), and similarly with AVC (OR 4.14, 95% CI 1.55–11.05, p=0.0045). In the multivariate adjusted analysis, a JAK2V617F allele burden >33% was significantly associated with a CACS >400 (OR 2.08, 95% CI 0.43–10.10, p=0.36), but not with AVC (OR 0.90, 95% CI 0.27–3.03, p=0.86). In the adjusted analysis the association between a JAK2V617F allele burden >33% and CACS >400 was significant (OR3.86, 95% CI 1.14–13.09, p=0.031), but the analysis on AVC was not (OR 1.59, 95% CI 0.42–6.04, p=0.50).

Conclusion

There is a significant association between a JAK2V617F allele burden >33% and the burden of coronary calcification in MPNs, measured as a CACS >400. The association remains significant after adjustment for cardiovascular risk factors.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Region Sjællands Sundhedsvidenskabelige ForskningsfondTømrermester Jørgen Holm og hustru Elisa F. Hansens Mindelegat

Inflammatory risk factors are not associated with coronary artery calcification in patients with myeloproliferative philadelphia-negative neoplasms

Background

Myeloproliferative Philadelphia-negative Neoplasms (MPNs) are hematological cancers associated with chronic inflammation and endothelial dysfunction, conditions that may lead to development of premature atherosclerosis.

Purpose

To investigate whether biomarkers of inflammation and endothelial dysfunction are associated with the degree of atherosclerotic burden, measured by Coronary Artery Calcium Score (CACS), in patients with MPNs.

Methods

Patients with a validated MPN diagnosis; essential thrombocythemia (ET), polycythemia vera (PV) or myelofibrosis (MF), were recruited between 2016 and 2018 from one single specialized hematologic center. Patients filled out a standardized questionnaire on medical history, current medication, alcohol and smoking habits and family medical history. They were examined by cardiac computed tomography (CT), Endothelial Peripheral Arterial Tone (EndoPAT), and a range of blood analyses. The atherosclerotic burden was evaluated by CACS. High sensitivity C-reactive protein (hs-CRP) and Neutrophil:Lymphocyt Ratio (NLR) were used as indicators of chronic inflammation. EndoPAT was applied to evaluate endothelial dysfunction, which is linked to development of atherosclerosis. The JAK2V617F-mutation is a common gene mutation in MPN-patients. It affects the gene coding the Janus kinase 2 (JAK2) protein, and can be detected by qPCR of peripheral blood or bone marrow. The JAK2V617F-mutation is a risk factor associated with both chronic inflammation and endothelial dysfunction. Multivariable logistic regression analyses were used to identify associations between potential risk factors and a higher CACS value.

Results

Among 170 included patients, 161 patients completed cardiac CT (mean age 65.5 (SD 10.5), 52% men). Baseline data is presented in Table 1. JAK2V617F-mutation was found in 137 (85%) patients, 53 patients (35%, n=152) had hs-CRP>2.0 mg/L, 107 (67%, n=160) had NLR>2.15 and 32 (21%, n=154) had an abnormal EndoPAT. Overall, 66 patients (41%) had a CACS>100, with no significant difference between ET (41%), PV (42%) and MF (50%) (p=0.3). In patients with a history of ischemic heart disease (IHD), 92% had CACS>100, compared to 37% in patients without prior IHD (p=0.0003).

Five independent factors associated with a CACS>100 were identified; age (OR: 1.3 [95% CI 1.1–1.4]), male sex (OR: 15.2 [95% CI 4.0–57.7]), prior IHD (OR: 15.9 [95% CI 1.2–202.4]), smoking (OR: 3.3 [95% CI 1.1–10.1]), and abnormal EndoPAT (OR: 4.8 [95% CI 1.1–20.0]) (Figure 1). Hs-CRP, NLR and JAK2V617F-mutation status were not significantly associated with CACS >100.

Conclusion

In this cohort of patients with MPNs, markers of chronic inflammation like hs-CRP and NLR were not associated with higher CACS, nor was the JAK2V617F-mutation. Traditional risk factors of cardiovascular disease seem to be sufficient to identify MPN patients with increased atherosclerotic burden, but measuring endothelial dysfunction provides additional information.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Department of Cardiology, Zealand University Hospital, Region Zealand, Denmark Table 1. Baseline characteristicsFigure 1. Odds ratio for CACS >100

A functional genomics screen identifying blood cell development genes in Drosophila by undergraduates participating in a course-based research experience

Undergraduate students participating in the UCLA Undergraduate Research Consortium for Functional Genomics (URCFG) have conducted a two-phased screen using RNA interference (RNAi) in combination with fluorescent reporter proteins to identify genes important for hematopoiesis in Drosophila. This screen disrupted the function of approximately 3500 genes and identified 137 candidate genes for which loss of function leads to observable changes in the hematopoietic development. Targeting RNAi to maturing, progenitor, and regulatory cell types identified key subsets that either limit or promote blood cell maturation. Bioinformatic analysis reveals gene enrichment in several previously uncharacterized areas, including RNA processing and export and vesicular trafficking. Lastly, the participation of students in this course-based undergraduate research experience (CURE) correlated with increased learning gains across several areas, as well as increased STEM retention, indicating that authentic, student-driven research in the form of a CURE represents an impactful and enriching pedagogical approach.

Maternal inflammation contributes to brain overgrowth and autism-associated behaviors through altered redox signaling in stem and progenitor cells

A period of mild brain overgrowth with an unknown etiology has been identified as one of the most common phenotypes in autism. Here, we test the hypothesis that maternal inflammation during critical periods of embryonic development can cause brain overgrowth and autism-associated behaviors as a result of altered neural stem cell function. Pregnant mice treated with low-dose lipopolysaccharide at embryonic day 9 had offspring with brain overgrowth, with a more pronounced effect in PTEN heterozygotes. Exposure to maternal inflammation also enhanced NADPH oxidase (NOX)-PI3K pathway signaling, stimulated the hyperproliferation of neural stem and progenitor cells, increased forebrain microglia, and produced abnormal autism-associated behaviors in affected pups. Our evidence supports the idea that a prenatal neuroinflammatory dysregulation in neural stem cell redox signaling can act in concert with underlying genetic susceptibilities to affect cellular responses to environmentally altered cellular levels of reactive oxygen species.

•

Mild maternal inflammation produces brain overgrowth and autistic behaviors in pups

•

Maternal inflammation increases stem cell division, ROS levels, and PI3K activation

•

Genetic susceptibility produces even greater brain overgrowth when combined with MIR

•

Overgrowth and some associated abnormal behaviors can be rescued by inhibition of NOX

Otorhinolaryngeal foreign bodies in children presenting to the emergency department

INTRODUCTION

Accidents with foreign bodies are common in the paediatric population. It is impossible to mandate that all foreign bodies (FB) in the ear, nose and throat (ENT) of children should be removed by the specialty-trained physicians. This study evaluates the management of ENT FB removal in children achieved by emergency physicians not trained in otolaryngology in an urban tertiary care paediatric emergency department.

METHODS

A retrospective study was conducted on consecutive paediatric patients presenting with suspected foreign body in the ear, nose or throat to the children's emergency department (ED) of KK Women's and Children's Hospital over a 10-month period. Removal methods, foreign body types, rates of successful removal and associated complications were evaluated.

RESULTS

There were 353 patients, most of whom presented after office hours. An attempt at removal of FB by the emergency physician was made in 76.8 percent of the cases. ENT specialist referral in the ED was made in 1.7 percent of the cases. 50.1 percent of cases were discharged after successful removal of FB in the ED. 4.2 percent of cases were admitted for removal of FB and 44.8 percent of cases were referred to the ENT specialist clinic for further assessment.

CONCLUSION

The emergency physician managed most cases in the ED and urgent referral to ENT specialists was not required. Complications and morbidity often occur from repeated attempts at removal of the FB. ENT opinion should be sought whenever there is doubt. The ED physician should be skilled in techniques of FB removal, especially throat FB, which had the lowest rate of success in our study.

Electrocardiographical case. Young man with generalised myalgia

A 24-year-old man presented with generalised malaise and myalgia for three days. He presented to the Emergency Department after a fall at his workplace due to weakness. 12-lead electrocardiogram (ECG) showed normal sinus rhythm with ST depression in the leads V4 to V6, with a U wave. The tallest U wave appeared in V3. These ECG features are characteristic of hypokalaemia. ECG changes in hypokalaemia and differential diagnosis are discussed. A second case of thyrotoxic periodic paralysis with similar ECG changes of hypokalaemia is also presented.

Right colonic involvement is associated with severe forms of ischemic colitis and occurs frequently in patients with chronic renal failure requiring hemodialysis

OBJECTIVE

The aim of this study was to identify factors associated with severe outcome in patients with ischemic colitis.

METHODS

The files of 60 consecutive inpatients (34 women, 26 men, mean age 67 yr) with ischemic colitis were reviewed. The following data were analyzed: age, sex, smoking, medications, history of cardiovascular disease, metabolic disease, chronic renal failure and hemodialysis, the time elapsed between the first symptoms and the diagnosis, and the site and extension of their colonic involvement. Patients were divided into two groups according to outcome: those with severe disease, including those who died from ischemic colitis (n = 3) or who required surgical resection (n = 21); and those with mild forms of colitis who were treated successfully without surgery (n = 36). The two groups were compared by means of univariate and multivariate analysis to identify factors associated with unfavorable outcomes. Only patients who had a complete examination of the colon (n = 51) were entered into the statistical analysis.

RESULTS

By univariate analysis, chronic renal failure (p = 0.03), hemodialysis (p = 0.01), short delay between symptoms and diagnosis (p = 0.01), and right colonic involvement (p = 0.002) were significantly more common in the patients with severe colitis. By logistic regression, right colonic involvement was the only factor independently associated with severity (p = 0.01). Right-sided lesions were present in 82% of patients on dialysis but in only 26% of patients not on dialysis (p = 0.0005).

CONCLUSIONS

Right colonic involvement is associated with severe forms of ischemic colitis and occurs frequently in patients with chronic renal failure requiring hemodialysis.

Proton pumping of mitochondrial complex I: differential activation by analogs of ubiquinone

As part of the ongoing studies aimed at elucidating the mechanism of the energy conserving function of mitochondrial complex I, NADH: ubiquinone (Q) reductase, we have investigated how short-chain Q analogs activate the proton pumping function of this complex. Using a pH-sensitive fluorescent dye we have monitored both the extent and initial velocity of proton pumping of complex I in submitochondrial particles. The results are consistent with two sites of interaction of Q analogs with complex I, each having different proton pumping capacity. One is the physiological site which leads to a rapid proton pumping and a stoichiometric consumption of NADH associated with the reduction of the most hydrophobic Q analogs. Of these, heptyl-Q appears to be the most efficient substrate in the assay of proton pumping. Q analogs with a short-chain of less than six carbons interact with a second site which drives a slow proton pumping activity associated with NADH oxidation that is overstoichiometric to the reduced quinone acceptor. This activity is also nonphysiological, since hydrophilic Q analogs show little or no respiratory control ratio of their NADH:Q reductase activity, contrary to hydrophobic Q analogs.

Inhibition of mitochondrial complex I may account for IDDM induced by intoxication with the rodenticide Vacor

Human intoxication with the rodenticide Vacor [N-3-pyridylmethyl-N'-p-nitrophenyl urea or 1-(4-nitrophenyl)-3-(3-pyridylmethyl) urea] induces acute IDDM. We report here that Vacor specifically inhibits the NADH:ubiquinone reductase activity of complex I in mammalian mitochondria. The activity of other respiratory enzymes of mitochondria is unaffected by Vacor at concentrations that completely inhibit the redox and energetic function of complex I. Vacor inhibition of complex I activity quantitatively correlates with the inhibition of insulin release in insulinoma cells and pancreatic islets and is also consistent with the doses reported in cases of human poisoning. These results indicate that the toxic and diabetogenic action of Vacor primarily derives from the inhibition of mitochondrial respiration of NAD-linked substrates in the high-energy demanding cells of the pancreatic islets. This newly identified mechanism of the pathological effects resulting from Vacor intoxication could constitute a paradigm in which to understand environmental or metabolic causes of IDDM.

The interaction of Q analogs, particularly hydroxydecyl benzoquinone (idebenone), with the respiratory complexes of heart mitochondria

We have studied the interaction of idebenone (2,3-dimethoxy-5-methy-6-(10-hydroxy)decyl-1,4-benzoquinone) with the energy-conserving complexes of the respiratory chain in beef heart mitochondria and compared its energetic efficiency with that of other analogs of coenzyme Q. Idebenone is a very effective substrate for succinate:Q reductase and ubiquinol:cytochrome c reductase, but it is clearly a poor substrate for NADH:Q reductase (complex I). Indeed, idebenone is a strong inhibitor of both the redox and proton pumping activity of complex I, showing effects in part similar to those of coenzyme Q-2. However, the mechanism of idebenone interaction with complex I may be different from that of Q-2 because of its different sensitivity to inhibitors. The possible relevance of the present findings to the therapeutic use of idebenone is discussed.

The specificity of mitochondrial complex I for ubiquinones

We report the first detailed study on the ubiquinone (coenzyme Q; abbreviated to Q) analogue specificity of mitochondrial complex I, NADH:Q reductase, in intact submitochondrial particles. The enzymic function of complex I has been investigated using a series of analogues of Q as electron acceptor substrates for both electron transport activity and the associated generation of membrane potential. Q analogues with a saturated substituent of one to three carbons at position 6 of the 2,3-dimethoxy-5-methyl-1,4-benzoquinone ring have the fastest rates of electron transport activity, and analogues with a substituent of seven to nine carbon atoms have the highest values of association constant derived from NADH:Q reductase activity. The rate of NADH:Q reductase activity is potently but incompletely inhibited by rotenone, and the residual rotenone-insensitive rate is stimulated by Q analogues in different ways depending on the hydrophobicity of their substituent. Membrane potential measurements have been undertaken to evaluate the energetic efficiency of complex I with various Q analogues. Only hydrophobic analogues such as nonyl-Q or undecyl-Q show an efficiency of membrane potential generation equivalent to that of endogenous Q. The less hydrophobic analogues as well as the isoprenoid analogue Q-2 are more efficient as substrates for the redox activity of complex I than for membrane potential generation. Thus the hydrophilic Q analogues act also as electron sinks and interact incompletely with the physiological Q site in complex I that pumps protons and generates membrane potential.

Breath analysis by API/MS--human exposure to volatile organic solvents

The expired breath of subjects, exposed for periods of ca. 90 min to atmospheres artificially contaminated with low levels of methanol, (ca. 100 ppm) toluene (ca. 50 ppm) or tetrachloroethylene, (ca. 50 ppm) was monitored during and after the exposure period using an atmospheric pressure ionization mass spectrometer, fitted with a direct breath analysis system. The retention of solvent by the subjects, estimated from steady state levels in the expired breath, averaged 82% of the inspired level for methanol, 83% for toluene and 87% for tetrachloroethylene. The elimination of unchanged solvent via respiration during the post exposure period followed first order kinetics with mean half life values of 24 min for methanol, 27 min for toluene and 79 min for tetrachloroethylene.

The effect of feeding various levels of dietary glycine in a pre-experimental diet to one-day old chicks on their subsequent glycine plus serine requirement

Two experiments were conducted to determine the effect of feeding chicks 1=9 days of age various levels of clycine in corn-casein and corn-soybean-corn gluten meal diets upon the subsequent glycine plus serine requirement of chicks during the remaining 10-21 day feeding period. Chicks in Experiment 1 fed corn-casein basal diets with 1.3% additional dietary glycine (2.15% total glycine plus serine) gained significantly (P less than or equal to 0.01) more weight during an initial 9-day feeding period than chicks fed basal diets with 0.3% and 0.9% supplemental glycine. Chicks fed the 2.15% glycine plus serine diets during the first 9 days posthatching and then fed basal diets containing 0.3% supplemental glycine (1.15% total glycine plus serine) for a 10-21 day feeding period gained weight equivalent to chicks fed 2.15% glycine plus serine diets for the entire 21-day period. The corn-casein basal diet contained 21.0% protein and 0.85% glycine plus serine. Chicks in Experiment 2 fed corn-soybean-corn gluten meal diets containing 1.8% glycine plus serine did not respond to glycine supplementation druing the initial 9-day feeding period or the 10-23 day feeding period. The results suggest feeding optimum levels of glycine to chicks during the first nine days after hatching decreases the requirement of glycine and serine during subsequent feeding periods.