A DNA methylation biomarker of alcohol consumption.

The lack of reliable measures of alcohol intake is a major obstacle to the diagnosis and treatment of alcohol-related diseases. Epigenetic modifications such as DNA methylation may provide novel biomarkers of alcohol use. To examine this possibility, we performed an epigenome-wide association study of methylation of cytosine-phosphate-guanine dinucleotide (CpG) sites in relation to alcohol intake in 13 population-based cohorts (ntotal=13 317; 54% women; mean age across cohorts 42-76 years) using whole blood (9643 European and 2423 African ancestries) or monocyte-derived DNA (588 European, 263 African and 400 Hispanic ancestry) samples. We performed meta-analysis and variable selection in whole-blood samples of people of European ancestry (n=6926) and identified 144 CpGs that provided substantial discrimination (area under the curve=0.90-0.99) for current heavy alcohol intake (⩾42 g per day in men and ⩾28 g per day in women) in four replication cohorts. The ancestry-stratified meta-analysis in whole blood identified 328 (9643 European ancestry samples) and 165 (2423 African ancestry samples) alcohol-related CpGs at Bonferroni-adjusted P<1 × 10-7. Analysis of the monocyte-derived DNA (n=1251) identified 62 alcohol-related CpGs at P<1 × 10-7. In whole-blood samples of people of European ancestry, we detected differential methylation in two neurotransmitter receptor genes, the γ-Aminobutyric acid-A receptor delta and γ-aminobutyric acid B receptor subunit 1; their differential methylation was associated with expression levels of a number of genes involved in immune function. In conclusion, we have identified a robust alcohol-related DNA methylation signature and shown the potential utility of DNA methylation as a clinically useful diagnostic test to detect current heavy alcohol consumption.

Effect of polymer deposition method on thermoresponsive polymer films and resulting cellular behavior.

Poly(N-isopropyl acrylamide) or pNIPAM is a thermoresponsive polymer that is widely studied for use in bioengineering applications. The interest in this polymer lies in the polymer's unique capability to undergo a sharp property change near physiological temperature, which aids in the spontaneous release of biological cells from substrates. Currently, there are many methods for depositing pNIPAM onto substrates, including atom-transfer radical polymerization (ATRP) and electron beam ionization. Each method yields pNIPAM-coated substrates with different surface characteristics that can influence cell behavior. In this work, we compare two methods of pNIPAM deposition: plasma deposition and codeposition with a sol-gel. The resulting pNIPAM films were analyzed for use as substrates for mammalian cell culture based on surface characterization (XPS, ToF-SIMS, AFM, contact angles), cell attachment/detachment studies, and an analysis of exocytosis function using carbon-fiber microelectrode amperometry (CFMA). We find that although both methods are useful for the deposition of functional pNIPAM films, plasma deposition is much preferred for cell-sheet engineering applications because of the films' thermoresponse, minimal change in cell density, and maintenance of supported cell exocytosis function.

High prevalence of osteoporosis in patients with chronic liver disease prior to liver transplantation.

Osteoporosis is a common complication of liver transplantation. Its pathogenesis is multifactorial, but preexisting bone disease in patients with chronic liver disease is likely to play an important role. The aim of this study was to evaluate bone mineral density in adult patients with chronic liver disease prior to liver transplantation. A total of 243 consecutive patients (128 male, 115 female; mean age 51.1years) with chronic liver disease undergoing assessment for transplantation, were recruited over a 4-year period. BMD measurements were made using dual energy X-ray absorptiometry in the lumbar spine (L1-L4) and femoral neck (FN). Osteoporosis and osteopenia were defined by WHO criteria. Osteoporosis at either L1-L4 or FN was present in 36.6%, osteopenia in 48.1%, and normal BMD in only 15.2% of patients. There was no difference in prevalence of osteoporosis between males and females (P = 0.442). Women with osteoporosis were on average 10 years older (56.2 +/- 1.4 years) than those with normal bone density (46.4 +/- 2.3 years) P = 0.002; in men, no statistically significant age effect was found. Patients with osteoporosis had on average lower body weight than those with normal bone density (64.9 +/- 1.8 kg vs 74.2 +/- 2.2 kg) P = 0.003. T-scores in patients with cholestatic liver disease were lower than in non-cholestatic disease and the lowest BMD values were found in patients with cystic fibrosis. Logistic regression revealed that in women, increasing age (P = 0.004; OR = 1.12; CI 1.04-1.21) and lower body weight (P = 0.01; OR = 0.95; CI 0.91-0.99) were significant independent risk factors for osteoporosis but menopausal status (P = 0.1; OR = 0.24; CI 0.05-1.32) and presence or absence of cholestasis (P = 0.326; OR = 1.54; CI 0.65-3.67) were not. There were no independent risk factors in men. This study demonstrates a high prevalence of osteoporosis in patients with chronic liver disease prior to liver transplantation, men and women being equally affected. With the exception of increasing age and lower body weight in women, no independent risk factors were found, emphasizing the importance of BMD measurements in these patients and the need for prophylactic measures to optimize bone health.

Plasma antioxidant consumption associated with ischemia/reperfusion during carotid endarterectomy.

BACKGROUND AND PURPOSE: Thirteen patients undergoing carotid endarterectomy were studied to correlate changes in jugular bulb venous oxygen saturation (SjO2) with indices of free radical production during cerebral ischemia/reperfusion. Levels of oxidant species were also monitored in arterial samples to determine any change across the cerebral circulation. METHODS: Blood was sampled from a venous catheter inserted in the ipsilateral jugular bulb and from an arterial catheter. Co-oximetry measurements were made to determine jugular bulb venous oxygenation saturation. To monitor changes in oxidant stress, a colorimetric assay was used to determine plasma antioxidant potential, and electron paramagnetic resonance spectroscopy was used to quantify free radical-spin trap adducts formed in a blood sample treated with the spin trap alpha-tert-butyl phenyl nitrone (PBN). RESULTS: SjO2 decreased significantly from 68 +/- 11% to 61 +/- 10% (P < .05) during clamping of the internal carotid artery and returned to baseline (65 +/- 11%) when the carotid clamp was removed. Jugular venous plasma antioxidant potential decreased significantly from 32.76 +/- 5.42% inhibition to 28.02 +/- 6.77% inhibition (P < .05). There was no concomitant change in arterial plasma antioxidant potential values, indicating a decrease in antioxidant capacity across the cerebral circulation. However, analysis of spin trap-free radical adducts did not provide conclusive evidence for free radical production. CONCLUSIONS: These results provide supportive evidence for oxidant production during cerebral ischemia/reperfusion in a clinical setting.