The Link between APOE4 Presence and Neuropsychological Test Performance among Mexican Americans and Non-Hispanic Whites of the Multiethnic Health & Aging Brain Study - Health Disparities Cohort.

INTRODUCTION: The APOEε4 allele is the single strongest genetic risk for late-onset Alzheimer's disease (AD). Prior work demonstrates that not only the APOEε4 allele varies by race/ethnicity but also the risk for AD and cognitive impairment conveyed by the APOEε4 allele varies by the racial/ethnic group as well as genetic ancestry. Here, we sought to examine the link between the APOEε4 and neuropsychological functioning among Mexican Americans (MAs). METHODS: Data were examined from 1,633 (852 MAs and 781 non-Hispanic Whites [NHWs]) participants of the Health & Aging Brain Study - Health Disparities (HABS-HD) and were enrolled with all requisite data to be included into the current analyses. RESULTS: The frequency of both ε4 and ε2 alleles was significantly lower among MAs as compared to NHWs. Among MAs, APOEε4 allele presence was associated specifically with poorer immediate and delayed memory (Wechsler Memory Scale - Third Edition [WMS-III] Logical Memory and Spanish-English Verbal Learning Test [SEVLT]). Among NHWs, APOEε4 allele presence was associated with poorer immediate and delayed memory as well as worse executive functioning (Trials B) and verbal fluency (Animal naming). DISCUSSION/CONCLUSION: The APOEε4 allele was associated with poorer cognition across multiple domains among NHWs; however, allele presence was specifically associated with poorer memory performance among MAs. When combined with prior work, the current findings demonstrate that the risk factors associated with cognitive dysfunction differ among MAs as compared to NHWs and require additional investigation.

Two-stage Bayesian GWAS of 9576 individuals identifies SNP regions that are targeted by miRNAs inversely expressed in Alzheimer's and cancer.

INTRODUCTION: We compared genetic variants between Alzheimer's disease (AD) and two age-related cancers-breast and prostate -to identify single-nucleotide polymorphisms (SNPs) that are associated with inverse comorbidity of AD and cancer. METHODS: Bayesian multinomial regression was used to compare sex-stratified cases (AD and cancer) against controls in a two-stage study. A ±500 KB region around each replicated hit was imputed and analyzed after merging individuals from the two stages. The microRNAs (miRNAs) that target the genes involving these SNPs were analyzed for miRNA family enrichment. RESULTS: We identified 137 variants with inverse odds ratios for AD and cancer located on chromosomes 19, 4, and 5. The mapped miRNAs within the network were enriched for miR-17 and miR-515 families. DISCUSSION: The identified SNPs were rs4298154 (intergenic), within TOMM40/APOE/APOC1, MARK4, CLPTM1, and near the VDAC1/FSTL4 locus. The miRNAs identified in our network have been previously reported to have inverse expression in AD and cancer.

Total cholesterol and neuropsychiatric symptoms in Alzheimer's disease: the impact of total cholesterol level and gender.

BACKGROUND: Neuropsychiatric symptoms (NPS) in Alzheimer's disease (AD) are a major factor in nursing home placement and a primary cause of stress for caregivers. Elevated cholesterol has been linked to psychiatric disorders and has been shown to be a risk factor for AD and to impact disease progression. The present study investigated the relationship between cholesterol and NPS in AD. METHODS: Data on cholesterol and NPS from 220 individuals (144 females, 76 males) with mild-to-moderate AD from the Texas Alzheimer's Research and Care Consortium (TARCC) cohort were analyzed. The total number of NPS and symptoms of hyperactivity, psychosis, affect and apathy were evaluated. Groups based on total cholesterol (TC; ≥200 vs. <200 mg/dl) were compared with regard to NPS. The impact of gender was also assessed. RESULTS: Individuals with high TC had lower MMSE scores as well as significantly more NPS and more symptoms of psychosis. When stratified by gender, males with high TC had significantly more NPS than females with high TC or than males or females with low TC. CONCLUSION: The role of elevated cholesterol in the occurrence of NPS in AD appears to be gender and symptom specific. A cross-validation of these findings will have implications for possible treatment interventions, especially for males with high TC.

Blood-Based mtDNA Quantification Indicates Population-Specific Differences Associated with Alzheimer's Disease-Related Risk.

BACKGROUND: Age is known to be the biggest risk factor for Alzheimer's disease (AD), and Mexican Americans (MAs), who are one of the fastest-aging populations in the United States, are at a uniquely elevated risk. Mitochondrial stress and dysfunction are key players in the progression of AD and are also known to be impacted by lifestyle and environmental exposures/stressors. OBJECTIVE: This study aimed to identify population-specific differences in indicators of mitochondrial stress and dysfunction associated with AD risk that are detectable in the blood. METHODS: Examining blood from both non-Hispanic white (NHW) and MA participants (N = 527, MA n = 284, NHW n = 243), mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) copy numbers were assessed through quantitative PCR. Data was stratified by population and sample type, and multiple linear regression analyses were performed to identify factors that may influence this phenotype of mitochondrial dysfunction. RESULTS: In the MA cohort, there was a significant relationship between cellular mtDNA:nDNA ratio and body mass index, CDR sum of boxes score, the APOEɛ2/ɛ3 genotype, and education. Further, there was a significant relationship between cell-free mtDNA copy number and both education and CDR sum score. In the NHW cohort, there was a significant relationship between cellular mtDNA:nDNA ratio and both age and CDR sum score. Age was associated with cell-free mtDNA in the NHW cohort. CONCLUSIONS: This evidence supports the existence of population-based differences in the factors that are predictive of this blood-based phenotype of mitochondrial dysfunction, which may be indicative of cognitive decline and AD risk.

Mitochondrial SOS: how mtDNA may act as a stress signal in Alzheimer's disease.

BACKGROUND: Alterations in mitochondrial DNA (mtDNA) levels have been observed in Alzheimer's disease and are an area of research that shows promise as a useful biomarker. It is well known that not only are the mitochondria a key player in producing energy for the cell, but they also are known to interact in other important intracellular processes as well as extracellular signaling and communication. BODY: This mini review explores how cells use mtDNA as a stress signal, particularly in Alzheimer's disease. We investigate the measurement of these mtDNA alterations, the mechanisms of mtDNA release, and the immunological effects from the release of these stress signals. CONCLUSION: Literature indicates a correlation between the release of mtDNA in Alzheimer's disease and increased immune responses, showing promise as a potential biomarker. However, several questions remain unanswered and there is great potential for future studies in this area.

Integrative blood-based characterization of oxidative mitochondrial DNA damage variants implicates Mexican American's metabolic risk for developing Alzheimer's disease.

Alzheimer's Disease (AD) continues to be a leading cause of death in the US. As the US aging population (ages 65 +) expands, the impact will disproportionately affect vulnerable populations, e.g., Hispanic/Latino population, due to their AD-related health disparities. Age-related regression in mitochondrial activity and ethnic-specific differences in metabolic burden could potentially explain in part the racial/ethnic distinctions in etiology that exist for AD. Oxidation of guanine (G) to 8-oxo-guanine (8oxoG) is a prevalent lesion and an indicator of oxidative stress and mitochondrial dysfunction. Damaged mtDNA (8oxoG) can serve as an important marker of age-related systemic metabolic dysfunction and upon release into peripheral circulation may exacerbate pathophysiology contributing to AD development and/or progression. Analyzing blood samples from Mexican American (MA) and non-Hispanic White (NHW) participants enrolled in the Texas Alzheimer's Research & Care Consortium, we used blood-based measurements of 8oxoG from both buffy coat PBMCs and plasma to determine associations with population, sex, type-2 diabetes, and AD risk. Our results show that 8oxoG levels in both buffy coat and plasma were significantly associated with population, sex, years of education, and reveal a potential association with AD. Furthermore, MAs are significantly burdened by mtDNA oxidative damage in both blood fractions, which may contribute to their metabolic vulnerability to developing AD.

Integrative Blood-Based Characterization of Oxidative Mitochondrial DNA Damage Variants Implicates Mexican Americans' Metabolic Risk for Developing Alzheimer's Disease.

Alzheimer's Disease (AD) continues to be a leading cause of death in the US. As the US aging population (ages 65+) expands, the impact will disproportionately affect vulnerable populations, e.g., Hispanic/Latinx population, due to their AD-related health disparities. Age-related regression in mitochondrial activity and ethnic-specific differences in metabolic burden could potentially explain in part the racial/ethnic distinctions in etiology that exist for AD. Oxidation of guanine (G) to 8-oxo-guanine (8oxoG) is a prevalent lesion and an indicator of oxidative stress and mitochondrial dysfunction. Damaged mtDNA (8oxoG) can serve as an important marker of age-related systemic metabolic dysfunction and upon release into peripheral circulation may exacerbate pathophysiology contributing to AD development and/or progression. Analyzing blood samples from Mexican American (MA) and non-Hispanic White (NHW) participants enrolled in the Texas Alzheimer's Research & Care Consortium, we used blood-based measurements of 8oxoG from both buffy coat PBMCs and plasma to determine associations with population, sex, type-2 diabetes, and AD risk. Our results show that 8oxoG levels in both buffy coat and plasma were significantly associated with population, sex, years of education, and reveal a potential association with AD. Furthermore, MAs are significantly burdened by mtDNA oxidative damage in both blood fractions, which may contribute to their metabolic vulnerability to developing AD.

A Synthetic Formula Amino Acid Diet Leads to Microbiome Dysbiosis, Reduced Colon Length, Inflammation, and Altered Locomotor Activity in C57BL/6J Mice.

The effects of synthetic, free-amino acid diets, similar to those prescribed as supplements for (phenylketonuria) PKU patients, on gut microbiota and overall health are not well understood. In the current, multidisciplinary study, we examined the effects of a synthetically-derived, low-fiber, amino acid diet on behavior, cognition, gut microbiome composition, and inflammatory markers. A cohort of 20 male C57BL/6J mice were randomly assigned to either a standard or synthetic diet (n = 10) at post-natal day 21 and maintained for 13 weeks. Sequencing of the 16S rRNA gene from fecal samples revealed decreased bacterial diversity, increased abundance of bacteria associated with disease, such as Prevotella, and a downward shift in gut microbiota associated with fermentation pathways in the synthetic diet group. Furthermore, there were decreased levels of short chain fatty acids and shortening of the colon in mice consuming the synthetic diet. Finally, we measured TNF-α, IL-6, and IL-10 in serum, the hippocampus, and colon, and found that the synthetic diet significantly increased IL-6 production in the hippocampus. These results demonstrate the importance of a multidisciplinary approach to future diet and microbiome studies, as diet not only impacts the gut microbiome composition but potentially systemic health as well.

Multi-ancestry genome-wide meta-analysis of 56,241 individuals identifies LRRC4C, LHX5-AS1 and nominates ancestry-specific loci PTPRK , GRB14 , and KIAA0825 as novel risk loci for Alzheimer's disease: the Alzheimer's Disease Genetics Consortium.

Limited ancestral diversity has impaired our ability to detect risk variants more prevalent in non-European ancestry groups in genome-wide association studies (GWAS). We constructed and analyzed a multi-ancestry GWAS dataset in the Alzheimer's Disease (AD) Genetics Consortium (ADGC) to test for novel shared and ancestry-specific AD susceptibility loci and evaluate underlying genetic architecture in 37,382 non-Hispanic White (NHW), 6,728 African American, 8,899 Hispanic (HIS), and 3,232 East Asian individuals, performing within-ancestry fixed-effects meta-analysis followed by a cross-ancestry random-effects meta-analysis. We identified 13 loci with cross-ancestry associations including known loci at/near CR1 , BIN1 , TREM2 , CD2AP , PTK2B , CLU , SHARPIN , MS4A6A , PICALM , ABCA7 , APOE and two novel loci not previously reported at 11p12 ( LRRC4C ) and 12q24.13 ( LHX5-AS1 ). Reflecting the power of diverse ancestry in GWAS, we observed the SHARPIN locus using 7.1% the sample size of the original discovering single-ancestry GWAS (n=788,989). We additionally identified three GWS ancestry-specific loci at/near ( PTPRK ( P =2.4×10 -8 ) and GRB14 ( P =1.7×10 -8 ) in HIS), and KIAA0825 ( P =2.9×10 -8 in NHW). Pathway analysis implicated multiple amyloid regulation pathways (strongest with P adjusted =1.6×10 -4 ) and the classical complement pathway ( P adjusted =1.3×10 -3 ). Genes at/near our novel loci have known roles in neuronal development ( LRRC4C, LHX5-AS1 , and PTPRK ) and insulin receptor activity regulation ( GRB14 ). These findings provide compelling support for using traditionally-underrepresented populations for gene discovery, even with smaller sample sizes.

Mitochondrial DNA oxidative mutations are elevated in Mexican American women potentially implicating Alzheimer's disease.

Mexican Americans (MAs) are the fastest-growing Hispanic population segment in the US; as this population increases in age, so will the societal burden of age-related diseases such as Alzheimer's disease (AD). Mitochondrial DNA (mtDNA) damage may be implicated in MA AD risk since metabolic comorbidities are more prevalent in this group. Oxidative damage to guanosine (8oxoG) is one of the most prevalent DNA lesions and a putative indicator of mitochondrial dysfunction. Testing blood samples from participants of the Texas Alzheimer's Research and Care Consortium, we found mtDNA 8oxoG mutational load to be significantly higher in MAs compared to non-Hispanic whites and that MA females are differentially affected. Furthermore, we identified specific mtDNA haplotypes that confer increased risk for oxidative damage and suggestive evidence that cognitive function may be related to 8oxoG burden. Our understanding of these phenomena will elucidate population- and sex-specific mechanisms of AD pathogenesis, informing the development of more precise interventions and therapeutic approaches for MAs with AD in the future.

Serum brain-derived neurotrophic factor levels are specifically associated with memory performance among Alzheimer's disease cases.

AIMS: Our purpose was to study the link between serum brain-derived neurotrophic factor (BDNF) levels and neuropsychological functioning through the Texas Alzheimer's Research Consortium cohort. METHODS: A total of 399 participants [probable Alzheimer's disease (AD) n = 198, controls n = 201] were available for analysis. The BDNF levels were assayed via multiplex immunoassay. Regression analyses were utilized to examine the relation between BDNF levels and neuropsychological functioning. RESULTS: There were no significant mean differences in BDNF levels between cases and controls. In the AD group, the BDNF levels were significantly negatively associated with the scores on immediate [B = -0.07 (0.02), t = -3.55, p = 0.001] and delayed [B = -0.05 (0.02), t = -2.79, p = 0.01] verbal memory and immediate [B = -0.12 (0.05), t = -2.70, p = 0.01] visual memory. No other neuropsychological variables were significantly related to the BDNF levels. The BDNF levels were not significantly related to the neuropsychological test scores in the control group. CONCLUSIONS: Increased serum BDNF levels were associated with poorer visual and verbal memory, but only among AD cases. The current findings point toward an upregulation of serum BDNF as one possible mechanism linked to memory disturbances in AD though it does not appear to be linked to disease severity.

Multiomics Investigation of Hypertension and White Matter Hyperintensity as a Source of Vascular Dementia or a Comorbidity to Alzheimer's Disease.

BACKGROUND: Age-related comorbidity is common and significantly increases the burden for the healthcare of the elderly. Alzheimer's disease (AD) and hypertension are the two most prevalent age-related conditions and are highly comorbid. While hypertension is a risk factor for vascular dementia (VD), hypertension with AD (ADHyp+) is often characterized as probable vascular dementia. In the absence of imaging and other diagnostic tests, differentiating the two pathological states is difficult. OBJECTIVE: Our goals are to (1) identify differences in CSF-based vascular dementia profiles, if any, between individuals who have AD only (ADHyp-), and individuals with ADHyp+ using CSF levels of amyloid ß, tau and p-tau, and (2) compare genome-wide DNA profiles of ADHyp- and ADHyp+ with an unaffected control population. METHOD: Genotype and clinical data were used to compare healthy controls to AD Hyp- vs. AD Hyp+. We compared the CSF biomarkers followed by evaluating genome wide profiles in three groups, and mapped SNPs to genes based on position and lowest p-value. The significant genes were examined for co-expression and known disease networks. RESULTS: We found no differences between Aß, tau and p-tau levels between ADHyp- and ADHyp+. We found TOMM40 to be associated with ADHyp- as expected but not with ADHyp+. Interestingly, SLC9A3R2 polymorphism was associated with ADHyp+, and significant gene expression changes were observed for neighboring genes. CONCLUSION: Through this exploratory study using a novel cohort stratification design, we highlight the genetic differences in clinically similar phenotypes, indicating the utility of genetic profiling in aiding differential diagnosis of ADHyp+ and VD.

The Health & Aging Brain among Latino Elders (HABLE) study methods and participant characteristics.

INTRODUCTION: Mexican Americans remain severely underrepresented in Alzheimer's disease (AD) research. The Health & Aging Brain among Latino Elders (HABLE) study was created to fill important gaps in the existing literature. METHODS: Community-dwelling Mexican Americans and non-Hispanic White adults and elders (age 50 and above) were recruited. All participants underwent comprehensive assessments including an interview, functional exam, clinical labs, informant interview, neuropsychological testing, and 3T magnetic resonance imaging (MRI) of the brain. Amyloid and tau positron emission tomography (PET) scans were added at visit 2. Blood samples were stored in the Biorepository. RESULTS: Data was examined from n = 1705 participants. Significant group differences were found in medical, demographic, and sociocultural factors. Cerebral amyloid and neurodegeneration imaging markers were significantly different between Mexican Americans and non-Hispanic Whites. DISCUSSION: The current data provide strong support for continued investigations that examine the risk factors for and biomarkers of AD among diverse populations.

Burn serum causes a CD14-dependent mitochondrial damage in primary cardiomyocytes.

Studies from animal models suggest that myocardial mitochondrial damage contributes to cardiac dysfunction after burn injury. In this report, we used an ex vivo model of primary cardiomyocyte culture to investigate the mechanisms of burn-induced mitochondrial impairment. Briefly, blood serum was collected from Sprague-Dawley (SD) rats subjected to 40% total body surface area burn and added (10% vol/vol) to primary cardiomyocytes prepared from SD rats. The effect of the burn serum on mitochondrial function and membrane integrity in the myocytes was analyzed. Exposure of myocytes to burn serum doubled the mitochondrial membrane damage measured by two independent assays. This treatment also significantly elevated mitochondrial oxidative stress, indicated by a more than 30% increase in lipid oxidation. Downregulation of mitochondrial antioxidant defense was also evident since the activities of the antioxidant enzymes superoxide dismutase and glutathione peroxidase were reduced by about 30% and 50%, respectively. Burn serum also induced deficiency of mitochondrial metabolism, indicated by a 30% decrease in the activity of cytochrome c oxidase. These mitochondrial dysfunctions appear to be generated by oxidative stress because burn serum induced a significant increase of mitochondrial oxygen species (mtROS) in cardiomyocytes, and pretreatment of cardiomyocytes with the antioxidant N-acetyl-cysteine prevented the mitochondrial damages induced by burn serum. Remarkably, the increase in mtROS was abolished by an antibody-mediated blockade of CD14. Furthermore, burn injury-induced mitochondrial damage in cardiomyocytes was prevented in CD14 knockout mice. Taken together, these data suggested that burn injury produces CD14-dependent mitochondrial damage via oxidative stress in myocardium.

IL-10 polymorphism associated with decreased risk for mortality after burn injury.

OBJECTIVE: Evaluation of single nucleotide polymorphisms (SNPs) in the interleukin-10 promoter (-592 and -819) on risk for death after burn injury. METHODS: Association between the IL-10 SNPs and outcome after burn injury was evaluated in a cohort of 265 patients from Parkland Hospital, Dallas, TX with ≥ 15% TBSA burns without non-burn trauma (ISS ≤ 16), traumatic or anoxic brain injury or spinal cord injury, who survived >48 h under an IRB-approved protocol. Clinical data were collected prospectively and genotyping was conducted by TaqMan assay. Whole blood from 31 healthy volunteers was stimulated with LPS (100 ng/mL) to determine the level of IL-10 expression for each allele by enzyme-linked immunosorbent assay (ELISA). RESULTS: After adjustment for percent total body surface area (TBSA) burned, inhalation injury, age, gender, and race/ethnicity, carriage of ­592A and/or ­819T was significantly associated (P = 0.014) with a decreased risk for death (adjusted odds ratio: 0.404; 95% CI: 0.197-0.829). As the candidate SNPs were in complete linkage disequilibrium, it was not possible to distinguish which allele was associated with decreased mortality risk. Age, inhalation injury, and full-thickness burn size were significantly associated with increased risk for death. In the LPS stimulated blood of healthy controls, carriage of the -592A and/or -819T allele demonstrated a trend for decreased levels of IL-10 (P = 0.079). CONCLUSION: Carriage of the ­592A and/or ­819T allele in the IL-10 promoter appears to reduce the risk for death after burn injury.

Differentiation of Hispanic biogeographic ancestry with 80 ancestry informative markers.

Ancestry informative single nucleotide polymorphisms (SNPs) can identify biogeographic ancestry (BGA); however, population substructure and relatively recent admixture can make differentiation difficult in heterogeneous Hispanic populations. Utilizing unrelated individuals from the Genomic Origins and Admixture in Latinos dataset (GOAL, n = 160), we designed an 80 SNP panel (Setser80) that accurately depicts BGA through STRUCTURE and PCA. We compared our Setser80 to the Seldin and Kidd panels via resampling simulations, which models data based on allele frequencies. We incorporated Admixed American 1000 Genomes populations (1000 G, n = 347), into a combined populations dataset to determine robustness. Using multinomial logistic regression (MLR), we compared the 3 panels on the combined dataset and found overall MLR classification accuracies: 93.2% Setser80, 87.9% Seldin panel, 71.4% Kidd panel. Naïve Bayesian classification had similar results on the combined dataset: 91.5% Setser80, 84.7% Seldin panel, 71.1% Kidd panel. Although Peru and Mexico were absent from panel design, we achieved high classification accuracy on the combined populations for Peru (MLR = 100%, naïve Bayes = 98%), and Mexico (MLR = 90%, naïve Bayes = 83.4%) as evidence of the portability of the Setser80. Our results indicate the Setser80 SNP panel can reliably classify BGA for individuals of presumed Hispanic origin.

Association of mitochondrial allele 4216C with increased risk for complicated sepsis and death after traumatic injury.

OBJECTIVES: Numerous studies have linked impaired mitochondrial activity with increased risk for clinical complications after injury. Furthermore, a number of nonsynonymous polymorphisms have been identified within the mitochondrial genome that are believed to impair cellular respiration. These DNA variants include a nonsynonymous polymorphism (T4216C) in the NADH dehydrogenase 1 gene (ND1), which encodes a key member of Complex I of the electron transport chain. We hypothesized that trauma patients who carry the ND1 4216C allele may be less able to generate the cellular energy necessary to mount an effective immune response and are at increased risk for death as well as sepsis complicated by organ dysfunction or shock. METHODS: We enrolled a cohort of 136 patients admitted to the Parkland Hospital Surgical intensive care unit (ICU) with significant trauma (Injury Severity Score > or = 16), > or =16 years of age, and with a minimum intensive care unit stay of > or =24 hours under a protocol approved by the UTSW and Parkland IRBs. Patients with brain death, spinal cord injury, active malignancy, HIV/AIDS or who survived <48 hours after admission were excluded. Clinical data were collected prospectively and T4216C was genotyped by polymerase chain reaction-restriction fragment length polymorphism. RESULTS: After multivariate adjustment for mechanism, severity of injury, units of packed red blood cells given in the first 24 hours, age, gender, and race/ethnicity, carriage of the 4216 C-allele was significantly associated with increased risk for sepsis complicated by organ dysfunction or septic shock (adjusted odds ratio [aOR] = 3.68; 95%CI: 1.17-11.52; p = 0.02) as well as death (aOR = 4.56; 95% CI: 1.05-19.79; p = 0.04), relative to carriers of the T-allele. CONCLUSION: Carriage of the mitochondrial 4216C-allele increases the risk for infectious complications and death after severe trauma.

Genome-Wide Methylation of Mild Cognitive Impairment in Mexican Americans Highlights Genes Involved in Synaptic Transport, Alzheimer's Disease-Precursor Phenotypes, and Metabolic Morbidities.

The Mexican American population is among the fastest growing aging population and has a younger onset of cognitive decline. This group is also heavily burdened with metabolic conditions such as hypertension, diabetes, and obesity. Unfortunately, limited research has been conducted in this group. Understanding methylation alterations, which are influenced by both genetic and lifestyle factors, is key to identifying and addressing the root cause for mild cognitive impairment, a clinical precursor for dementia. We conducted an epigenome-wide association study on a community-based Mexican American population using the Illumina EPIC array. Following rigorous quality control measures, we identified 10 CpG sites to be differentially methylated between normal controls and individuals with mild cognitive impairment annotated to PKIB, KLHL29, SEPT9, OR2C3, CPLX3, BCL2L2-PABPN1, and CCNY. We found four regions to be differentially methylated in TMEM232, SLC17A8, ALOX12, and SEPT8. Functional gene-set analysis identified four gene-sets, RIN3, SPEG, CTSG, and UBE2L3, as significant. The gene ontology and pathway analyses point to neuronal cell death, metabolic dysfunction, and inflammatory processes. We found 1,450 processes to be enriched using empirical Bayes gene-set enrichment. In conclusion, the functional overlap of differentially methylated genes associated with cognitive impairment in Mexican Americans implies cross-talk between metabolically-instigated systemic inflammation and disruption of synaptic vesicular transport.

Variations of the lung microbiome and immune response in mechanically ventilated surgical patients.

Mechanically ventilated surgical patients have a variety of bacterial flora that are often undetectable by traditional culture methods. The source of infection in many of these patients remains unclear. To address this clinical problem, the microbiome profile and host inflammatory response in bronchoalveolar lavage samples from the surgical intensive care unit were examined relative to clinical pathology diagnoses. The hypothesis was tested that clinical diagnosis of respiratory tract flora were similar to culture positive lavage samples in both microbiome and inflammatory profile. Bronchoalveolar lavage samples were collected in the surgical intensive care unit as standard of care for intubated individuals with a clinical pulmonary infection score of >6 or who were expected to be intubated for >48 hours. Cytokine analysis was conducted with the Bioplex Pro Human Th17 cytokine panel. The microbiome of the samples was sequenced for the 16S rRNA region using the Ion Torrent. Microbiome diversity analysis showed the culture-positive samples had the lowest levels of diversity and culture negative with the highest based upon the Shannon-Wiener index (culture positive: 0.77 ± 0.36, respiratory tract flora: 2.06 ± 0.73, culture negative: 3.97 ± 0.65). Culture-negative samples were not dominated by a single bacterial genera. Lavages classified as respiratory tract flora were more similar to the culture-positive in the microbiome profile. A comparison of cytokine expression between groups showed increased levels of cytokines (IFN-g, IL-17F, IL-1B, IL-31, TNF-a) in culture-positive and respiratory tract flora groups. Culture-positive samples exhibited a more robust immune response and reduced diversity of bacterial genera. Lower cytokine levels in culture-negative samples, despite a greater number of bacterial species, suggest a resident nonpathogenic bacterial community may be indicative of a normal pulmonary environment. Respiratory tract flora samples were most similar to the culture-positive samples and may warrant classification as culture-positive when considering clinical treatment.

CD14-159 C allele is associated with increased risk of mortality after burn injury.

Although comprehension of postburn pathophysiology has grown in recent years, we are still unable to accurately identify burn patients who are at an increased risk of infectious complications and death. This unexplained variation is likely influenced by heritable factors; the genetic predisposition for death from infection has been estimated as greater than that for cardiovascular disease or cancer. Identify genetic variants associated with increased mortality after burn injury. A total of 233 patients with burns of 15% of total body surface area or greater or smoke inhalation injury who survived more than 48 h after admission and were without significant nonburn-related trauma (injury severity score > or = 16), traumatic or anoxic brain injury, or spinal cord injury. We examined the influence of genotype at five candidate loci (interleukin [IL]-1beta, IL-6, tumor necrosis factor-alpha, toll-like receptor 4, CD14) on mortality risk after burn injury. DNA was isolated from residual blood from laboratory draws and candidate genotypes were determined by real-time polymerase chain reaction using TaqMan probes. Clinical data were prospectively collected into a local, curated database. Allelic associations were analyzed by multivariate logistic regression. After adjustment for age, full-thickness burn size, inhalation injury, ethnicity, and sex, carriage of the CD14-159 C allele imparted at least a 1.3-fold increased risk for death after burn injury, relative to TT homozygotes (adjusted odds ratio, 2.9; 95% confidence interval, 1.3-6.8; P = 0.01). This association was stronger (adjusted odds ratio, 3.3; 95% confidence interval, 1.3-8.4; P = 0.01) when the analysis was conducted only on deaths accompanied by severe sepsis. In addition, a gene dosage effect for increased mortality was apparent for carriage of the CD14-159 C allele (P = 0.006). The gene dosage effect remained when white, Hispanic, or African American patients were analyzed independently, although statistical significance was not achieved in the subgroup analysis. None of the other single nucleotide polymorphisms examined were significantly associated with mortality. These data provide strong evidence that a CD14 promoter allele that is known to impart lower baseline and induced CD14 transcription also affects mortality risk after burn injury. A potential (although untested) mechanism for our observation is that reduced signaling through CD14/toll-like receptor 4 in response to challenge by gram-negative bacteria after burns results in a blunted innate immune response and subsequent increased likelihood for systemic infection and death.