Bradley E. Aouizerat

Abstract

Epigenetic mechanisms provide an adaptive layer of control in the regulation of gene expression that enables an organism to adjust to a changing environment. Epigenetic regulation increases the functional complexity of deoxyribonucleic acid (DNA) by altering chromatin structure, nuclear organization, and transcript stability. These changes may additively or synergistically influence gene expression and result in long-term molecular and functional consequences independent of the DNA sequence that may ultimately define an individual's phenotype. This article (1) describes histone modification, DNA methylation, and expression of small noncoding RNA species; (2) reviews the most common methods used to measure these epigenetic changes; and (3) presents factors that need to be considered when choosing a specific tissue to evaluate for epigenetic changes.

Abstract

AIMS:: Fish and ω-3 fatty acids are reported to be beneficial in pediatric nonalcoholic fatty liver disease (NAFLD), but no studies have assessed their relation to histological severity. The objectives of this study were to evaluate the dietary intake of fish and ω-3 fatty acids in children with biopsy-proven NAFLD, and examine their association with serological and histological indicators of disease. METHODS:: This was a cross-sectional analysis of 223 children (6-18 years) who participated in the Treatment of Nonalcoholic Fatty Liver Disease in Children trial or the NAFLD Database study conducted by the Nonalcoholic Steatohepatitis Clinical Research Network. The distribution of fish and ω-3 fatty acid intake was determined from responses to the Block Brief 2000 Food Frequency Questionnaire, and analyzed for associations with serum alanine aminotransferase, histological features of fatty liver disease, and diagnosis of steatohepatitis after adjusting for demographic, anthropometric, and dietary variables. RESULTS:: The minority of subjects consumed the recommended 8 ounces of fish per week (22/223 [10%]) and 200 mg of long-chain ω-3 fatty acids per day (12/223 [5%]). Lack of fish and long-chain ω-3 fatty acid intake was associated with greater portal (P=0.03 and P=0.10, respectively) and lobular inflammation (P=0.09 and P=0.004, respectively) after controlling for potential confounders. CONCLUSIONS:: Fish and ω-3 fatty acid intake was insufficient in children with NAFLD, which may increase susceptibility to hepatic inflammation. Patients with pediatric NAFLD should be encouraged to consume the recommended amount of fish per week.

Abstract

OBJECTIVE: HIV infection and illicit drug use are each associated with diminished cognitive performance. This study examined the separate and interactive effects of HIV and recent illicit drug use on verbal memory, processing speed, and executive function in the multicenter Women's Interagency HIV Study. METHODS: Participants included 952 HIV-infected and 443 HIV-uninfected women (mean age = 42.8, 64% African-American). Outcome measures included the Hopkins Verbal Learning Test - Revised and the Stroop test. Three drug use groups were compared: recent illicit drug users (cocaine or heroin use in past 6 months, n = 140), former users (lifetime cocaine or heroin use but not in past 6 months, n = 651), and nonusers (no lifetime use of cocaine or heroin, n = 604). RESULTS: The typical pattern of recent drug use was daily or weekly smoking of crack cocaine. HIV infection and recent illicit drug use were each associated with worse verbal learning and memory (P < 0.05). Importantly, there was an interaction between HIV serostatus and recent illicit drug use such that recent illicit drug use (compared with nonuse) negatively impacted verbal learning and memory only in HIV-infected women (P < 0.01). There was no interaction between HIV serostatus and illicit drug use on processing speed or executive function on the Stroop test. CONCLUSIONS: The interaction between HIV serostatus and recent illicit drug use on verbal learning and memory suggests a potential synergistic neurotoxicity that may affect the neural circuitry underlying performance on these tasks.

Abstract

OBJECTIVE: The Met allele of the catechol-O-methyltransferase (COMT) Val158Met polymorphism is associated with increased cortical dopamine and risk behaviors including illicit drug use and unprotected sex. Therefore, we examined whether or not the distribution of the Val158Met genotype differed between HIV-infected and HIV-uninfected women. DESIGN: Cross-sectional analysis using data from the Women's Interagency HIV Study (WIHS), the largest longitudinal cohort study of HIV in women. METHODS: We conducted an Armitage-Cochran test and logistic regression to compare genotype frequencies between 1848 HIV-infected and 612 HIV-uninfected women in WIHS. RESULTS: The likelihood of carrying one or two Met alleles was greater in HIV-infected women (61%) compared to HIV-uninfected women (54%), Z = -3.60, P <0.001. CONCLUSION: We report the novel finding of an association between the Val158Met genotype and HIV serostatus that may be mediated through the impact of dopamine function on propensity for risk-taking.

Abstract

Proteinuria is associated with adverse clinical outcomes in HIV infection. Here we evaluated whether APOL1 risk alleles, previously associated with advanced kidney disease, are independently associated with proteinuria in HIV infection in a cross-sectional study of HIV-infected women in the Women's Interagency HIV Study. We estimated the percent difference in urine protein excretion and odds of proteinuria (≥200 mg/g) associated with two versus one or no APOL1 risk allele using linear and logistic regression, respectively. Of 1285 women successfully genotyped, 379 carried one and 80 carried two risk alleles. Proteinuria was present in 124 women, 78 of whom had proteinuria confirmed on a second sample. In women without prior AIDS, two risk alleles were independently associated with a 69% higher urine protein excretion (95% confidence interval (CI): 36, 108) and five-fold higher odds of proteinuria (95% CI: 2.45, 10.37) as compared with one or no risk allele. No association was found in women with prior AIDS. Analyses in which women with impaired kidney function were excluded and proteinuria was confirmed by a second urine sample yielded similar estimates. Thus, APOL1 risk alleles are associated with significant proteinuria in HIV-infected persons without prior clinical AIDS, independent of clinical factors traditionally associated with proteinuria. Trials are needed to determine whether APOL1 genotyping identifies individuals who could benefit from earlier intervention to prevent overt renal disease.

Abstract

Context: Fatigue is a prevalent symptom among adults living with HIV. There is increasing evidence that fatigue and energy are related, yet distinct constructs. Although HIV-related fatigue has been well studied, little is known about perceived energy and how it relates to fatigue, individual characteristics, and other symptoms. Objectives: To describe the experience of perceived energy in adults with HIV and evaluate its relationship to demographic and clinical characteristics as well as symptoms of fatigue, sleep disturbance, anxiety, depression, and daytime function. Methods: The design was descriptive, comparative, and correlational. The sample of 318 adults with HIV completed a demographic questionnaire; the Memorial Symptom Assessment Scale; and measures of fatigue, sleep disturbance, anxiety, depressive symptoms, and daytime function. Medical records were reviewed for disease and treatment data. Participants who reported a lack of energy were compared with those who did not on demographic, clinical, and symptom variables. Regression models of perceived energy and its interference with daytime function also were evaluated. Results: Perceived lack of energy was highly prevalent (65%) and more strongly related to interference with daytime function than more general measures of fatigue severity, even when controlling for other characteristics and symptoms. Like other aspects of fatigue, lack of energy was associated with sleep disturbance, anxiety, and depressive symptoms. Lack of energy was more strongly related to morning fatigue than to evening fatigue. Conclusion: Lack of energy interferes with daytime function and is not just the inverse of fatigue but a distinct perception that differs from fatigue.

Abstract

The purposes of this study were to evaluate for differences in phenotypic and genotypic characteristics in women who did and did not develop lymphedema (LE) following breast cancer treatment. Breast cancer patients completed a number of self-report questionnaires. LE was evaluated using bioimpedance spectroscopy. Genotyping was done using a custom genotyping array. No differences were found between patients with (n = 155) and without LE (n = 387) for the majority of the demographic and clinical characteristics. Patients with LE had a significantly higher body mass index, more advanced disease and a higher number of lymph nodes removed. Genetic associations were identified for four genes (i.e., lymphocyte cytosolic protein 2 (rs315721), neuropilin-2 (rs849530), protein tyrosine kinase (rs158689), vascular cell adhesion molecule 1 (rs3176861)) and three haplotypes (i.e., Forkhead box protein C2 (haplotype A03), neuropilin-2 (haplotype F03), vascular endothelial growth factor-C (haplotype B03)) involved in lymphangiogensis and angiogenesis. These genetic associations suggest a role for a number of lymphatic and angiogenic genes in the development of LE following breast cancer treatment.

Abstract

MicroRNAs (miRs) are epigenetic regulators of messenger RNAs' (mRNA) expression of polypeptides. As such, miRs represent an intriguing mechanism by which gene-environment interactions are hypothesized to occur on the level of epigenetic control over gene expression. In addition to promising findings from in vitro studies indicating that miRs have the potential to function as therapeutic agents in modifying the course of pathophysiologic conditions, recent human studies revealed changes in miR expression patterns in response to behavioral interventions. The authors provide an overview of how miRs are preserved and isolated from other genetic material and describe commonly used methods for measuring miR in the research setting, including Northern blot, polymerase chain reaction, and microarray. The authors also introduce bioinformatic approaches to analysis of high-throughput miR expression and techniques used to create predictive models of miR-mRNA binding to describe possible physiologic pathways affected by specific miRs.

Abstract

MicroRNAs are structural components of an epigenetic mechanism of posttranscriptional regulation of messenger RNA translation. Recently, there has been significant interest in the application of microRNA as a blood-based biomarker of underlying physiological conditions. Dyslipidemia is a complex, heterogeneous condition conferring substantially increased risk for cardiovascular disease. The purpose of this review is to describe the current body of knowledge on the role of microRNA regulation of lipoprotein metabolism in humans and to discuss relevant methodological and study design considerations. We highlight the potential roles for microRNA in geneenvironment interactions.