Browsing by Subject "Lipids"
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Item Open Access Alterations in acylcarnitines, amines, and lipids inform about the mechanism of action of citalopram/escitalopram in major depression.(Translational psychiatry, 2021-03-02) MahmoudianDehkordi, Siamak; Ahmed, Ahmed T; Bhattacharyya, Sudeepa; Han, Xianlin; Baillie, Rebecca A; Arnold, Matthias; Skime, Michelle K; John-Williams, Lisa St; Moseley, M Arthur; Thompson, J Will; Louie, Gregory; Riva-Posse, Patricio; Craighead, W Edward; McDonald, William; Krishnan, Ranga; Rush, A John; Frye, Mark A; Dunlop, Boadie W; Weinshilboum, Richard M; Kaddurah-Daouk, Rima; Mood Disorders Precision Medicine Consortium (MDPMC)Selective serotonin reuptake inhibitors (SSRIs) are the first-line treatment for major depressive disorder (MDD), yet their mechanisms of action are not fully understood and their therapeutic benefit varies among individuals. We used a targeted metabolomics approach utilizing a panel of 180 metabolites to gain insights into mechanisms of action and response to citalopram/escitalopram. Plasma samples from 136 participants with MDD enrolled into the Mayo Pharmacogenomics Research Network Antidepressant Medication Pharmacogenomic Study (PGRN-AMPS) were profiled at baseline and after 8 weeks of treatment. After treatment, we saw increased levels of short-chain acylcarnitines and decreased levels of medium-chain and long-chain acylcarnitines, suggesting an SSRI effect on β-oxidation and mitochondrial function. Amines-including arginine, proline, and methionine sulfoxide-were upregulated while serotonin and sarcosine were downregulated, suggesting an SSRI effect on urea cycle, one-carbon metabolism, and serotonin uptake. Eighteen lipids within the phosphatidylcholine (PC aa and ae) classes were upregulated. Changes in several lipid and amine levels correlated with changes in 17-item Hamilton Rating Scale for Depression scores (HRSD17). Differences in metabolic profiles at baseline and post-treatment were noted between participants who remitted (HRSD17 ≤ 7) and those who gained no meaningful benefits (<30% reduction in HRSD17). Remitters exhibited (a) higher baseline levels of C3, C5, alpha-aminoadipic acid, sarcosine, and serotonin; and (b) higher week-8 levels of PC aa C34:1, PC aa C34:2, PC aa C36:2, and PC aa C36:4. These findings suggest that mitochondrial energetics-including acylcarnitine metabolism, transport, and its link to β-oxidation-and lipid membrane remodeling may play roles in SSRI treatment response.Item Open Access C-reactive protein, fibrinogen, and cardiovascular disease prediction.(The New England journal of medicine, 2012-10) Emerging Risk Factors Collaboration; Kaptoge, Stephen; Di Angelantonio, Emanuele; Pennells, Lisa; Wood, Angela M; White, Ian R; Gao, Pei; Walker, Matthew; Thompson, Alexander; Sarwar, Nadeem; Caslake, Muriel; Butterworth, Adam S; Amouyel, Philippe; Assmann, Gerd; Bakker, Stephan JL; Barr, Elizabeth LM; Barrett-Connor, Elizabeth; Benjamin, Emelia J; Björkelund, Cecilia; Brenner, Hermann; Brunner, Eric; Clarke, Robert; Cooper, Jackie A; Cremer, Peter; Cushman, Mary; Dagenais, Gilles R; D'Agostino, Ralph B; Dankner, Rachel; Davey-Smith, George; Deeg, Dorly; Dekker, Jacqueline M; Engström, Gunnar; Folsom, Aaron R; Fowkes, F Gerry R; Gallacher, John; Gaziano, J Michael; Giampaoli, Simona; Gillum, Richard F; Hofman, Albert; Howard, Barbara V; Ingelsson, Erik; Iso, Hiroyasu; Jørgensen, Torben; Kiechl, Stefan; Kitamura, Akihiko; Kiyohara, Yutaka; Koenig, Wolfgang; Kromhout, Daan; Kuller, Lewis H; Lawlor, Debbie A; Meade, Tom W; Nissinen, Aulikki; Nordestgaard, Børge G; Onat, Altan; Panagiotakos, Demosthenes B; Psaty, Bruce M; Rodriguez, Beatriz; Rosengren, Annika; Salomaa, Veikko; Kauhanen, Jussi; Salonen, Jukka T; Shaffer, Jonathan A; Shea, Steven; Ford, Ian; Stehouwer, Coen DA; Strandberg, Timo E; Tipping, Robert W; Tosetto, Alberto; Wassertheil-Smoller, Sylvia; Wennberg, Patrik; Westendorp, Rudi G; Whincup, Peter H; Wilhelmsen, Lars; Woodward, Mark; Lowe, Gordon DO; Wareham, Nicholas J; Khaw, Kay-Tee; Sattar, Naveed; Packard, Chris J; Gudnason, Vilmundur; Ridker, Paul M; Pepys, Mark B; Thompson, Simon G; Danesh, JohnThere is debate about the value of assessing levels of C-reactive protein (CRP) and other biomarkers of inflammation for the prediction of first cardiovascular events.We analyzed data from 52 prospective studies that included 246,669 participants without a history of cardiovascular disease to investigate the value of adding CRP or fibrinogen levels to conventional risk factors for the prediction of cardiovascular risk. We calculated measures of discrimination and reclassification during follow-up and modeled the clinical implications of initiation of statin therapy after the assessment of CRP or fibrinogen.The addition of information on high-density lipoprotein cholesterol to a prognostic model for cardiovascular disease that included age, sex, smoking status, blood pressure, history of diabetes, and total cholesterol level increased the C-index, a measure of risk discrimination, by 0.0050. The further addition to this model of information on CRP or fibrinogen increased the C-index by 0.0039 and 0.0027, respectively (P<0.001), and yielded a net reclassification improvement of 1.52% and 0.83%, respectively, for the predicted 10-year risk categories of "low" (<10%), "intermediate" (10% to <20%), and "high" (≥20%) (P<0.02 for both comparisons). We estimated that among 100,000 adults 40 years of age or older, 15,025 persons would initially be classified as being at intermediate risk for a cardiovascular event if conventional risk factors alone were used to calculate risk. Assuming that statin therapy would be initiated in accordance with Adult Treatment Panel III guidelines (i.e., for persons with a predicted risk of ≥20% and for those with certain other risk factors, such as diabetes, irrespective of their 10-year predicted risk), additional targeted assessment of CRP or fibrinogen levels in the 13,199 remaining participants at intermediate risk could help prevent approximately 30 additional cardiovascular events over the course of 10 years.In a study of people without known cardiovascular disease, we estimated that under current treatment guidelines, assessment of the CRP or fibrinogen level in people at intermediate risk for a cardiovascular event could help prevent one additional event over a period of 10 years for every 400 to 500 people screened. (Funded by the British Heart Foundation and others.).Item Open Access Case management of patients with Type 2 diabetes mellitus: a cross-sectional survey in Chongqing, China.(BMC Health Serv Res, 2017-02-11) He, Miao; Gao, Jiaqi; Liu, Weiwei; Tang, Xiaojun; Tang, Shenglan; Long, QianBACKGROUND: Type 2 diabetes mellitus has been identified as one of the priority diseases and included in the essential public health service package in China. This study investigated the frequency of follow-up visits and contents of care for case management of patients with Type 2 diabetes in Chongqing located in the western China, in terms of the regional practice guideline; and analyzed factors associated with the use of care. METHODS: A cross-sectional survey was conducted with patients diagnosed with Type 2 diabetes in two areas in Chongqing. Total 502 participants (out of 664 people eligible) completed the interview. The outcome measures included at least four follow-up visits in a year, annual HbA1c test, blood lipid test and diabetic screening for nephropathy and eyes. Logistic regression analysis was applied to examine the association between participants' demographic and socio-economic characteristics and outcome measures. RESULTS: Over the one-year study period, 65% of participants had four or more follow-up visits. In light of the recommended tests, the proportions of having HbA1c test, blood lipid test and screening for nephropathy and eyes annually were 8, 54, 45 and 44%, respectively. After adjusting for study sites, age, sex, education, type of residence, level of income, the patients who were covered by Urban Employee Basic Medical Insurance, were enrolled in the targeted disease reimbursement program, and lived with diabetes more than five years were more likely to have regular follow-up visits and the recommended tests. CONCLUSIONS: Case management for patients with Type 2 diabetes mellitus was not effectively implemented in terms of frequency of follow-up visits and recommended tests over one-year period, as indicated in the regional practice guideline.Item Open Access Characterization of a canine model of glycogen storage disease type IIIa.(Dis Model Mech, 2012-11) Yi, Haiqing; Thurberg, Beth L; Curtis, Sarah; Austin, Stephanie; Fyfe, John; Koeberl, Dwight D; Kishnani, Priya S; Sun, BaodongGlycogen storage disease type IIIa (GSD IIIa) is an autosomal recessive disease caused by deficiency of glycogen debranching enzyme (GDE) in liver and muscle. The disorder is clinically heterogeneous and progressive, and there is no effective treatment. Previously, a naturally occurring dog model for this condition was identified in curly-coated retrievers (CCR). The affected dogs carry a frame-shift mutation in the GDE gene and have no detectable GDE activity in liver and muscle. We characterized in detail the disease expression and progression in eight dogs from age 2 to 16 months. Monthly blood biochemistry revealed elevated and gradually increasing serum alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) activities; serum creatine phosphokinase (CPK) activity exceeded normal range after 12 months. Analysis of tissue biopsy specimens at 4, 12 and 16 months revealed abnormally high glycogen contents in liver and muscle of all dogs. Fasting liver glycogen content increased from 4 months to 12 months, but dropped at 16 months possibly caused by extended fibrosis; muscle glycogen content continually increased with age. Light microscopy revealed significant glycogen accumulation in hepatocytes at all ages. Liver histology showed progressive, age-related fibrosis. In muscle, scattered cytoplasmic glycogen deposits were present in most cells at 4 months, but large, lake-like accumulation developed by 12 and 16 months. Disruption of the contractile apparatus and fraying of myofibrils was observed in muscle at 12 and 16 months by electron microscopy. In conclusion, the CCR dogs are an accurate model of GSD IIIa that will improve our understanding of the disease progression and allow opportunities to investigate treatment interventions.Item Open Access Countering clinical inertia in lipid management: Expert workshop summary.(American heart journal, 2018-12) Zullig, Leah L; Egbuonu-Davis, Lisa; Trasy, Anjali; Oshotse, Christiana; Goldstein, Karen M; Bosworth, Hayden BItem Open Access EAE cerebrospinal fluid augments in vitro phagocytosis and metabolism of CNS myelin by macrophages.(J Neurosci Res, 1992-07) Sommer, MA; Forno, LS; Smith, MEPrevious studies from this laboratory have shown that CNS myelin is phagocytized and metabolized by cultured rat macrophages to a much larger extent when myelin is pretreated with serum containing antibodies to myelin constituents than when it is left untreated or pretreated with non-specific serum. In this study the effect of cerebrospinal fluid (CSF) from rabbits with experimental allergic encephalomyelitis (EAE) in promoting myelin phagocytosis was examined. Fourteen rabbits were immunized with purified myelin in Freund's complete adjuvant, seven of which developed clinical EAE symptoms. Serum and CSF were collected from EAE and control rabbits, and the CSF was centrifuged to remove cells. Sera and CSF from these rabbits and from Freund's adjuvant-immunized controls and untreated controls were measured for IgG content by radial diffusion assay, their myelin antibody characteristics were analyzed by immunoblots, and the ability of these serum and CSF samples to promote myelin phagocytosis when used for myelin opsonization was examined. The ability of a CSF sample to enhance radioactive myelin uptake and phagocytosis by cultured macrophages as measured by the appearance of radioactive cholesterol ester was linearly proportional to its total IgG titer, and correlated approximately both with clinical symptoms of the animal and the presence of antibody against the myelin constituents myelin basic protein, proteolipid protein, and galactocerebroside. The cholesterol esterification activities of EAE sera correlated to a lesser extent with IgG levels and clinical symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)Item Open Access Immunomodulatory lipid mediator profiling of cerebrospinal fluid following surgery in older adults.(Scientific reports, 2021-02-04) Terrando, Niccolò; Park, John J; Devinney, Michael; Chan, Cliburn; Cooter, Mary; Avasarala, Pallavi; Mathew, Joseph P; Quinones, Quintin J; Maddipati, Krishna Rao; Berger, Miles; MADCO-PC Study TeamArachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) derived lipids play key roles in initiating and resolving inflammation. Neuro-inflammation is thought to play a causal role in perioperative neurocognitive disorders, yet the role of these lipids in the human central nervous system in such disorders is unclear. Here we used liquid chromatography-mass spectrometry to quantify AA, DHA, and EPA derived lipid levels in non-centrifuged cerebrospinal fluid (CSF), centrifuged CSF pellets, and centrifuged CSF supernatants of older adults obtained before, 24 h and 6 weeks after surgery. GAGE analysis was used to determine AA, DHA and EPA metabolite pathway changes over time. Lipid mediators derived from AA, DHA and EPA were detected in all sample types. Postoperative lipid mediator changes were not significant in non-centrifuged CSF (p > 0.05 for all three pathways). The AA metabolite pathway showed significant changes in centrifuged CSF pellets and supernatants from before to 24 h after surgery (p = 0.0000247, p = 0.0155 respectively), from before to 6 weeks after surgery (p = 0.0000497, p = 0.0155, respectively), and from 24 h to 6 weeks after surgery (p = 0.0000499, p = 0.00363, respectively). These findings indicate that AA, DHA, and EPA derived lipids are detectable in human CSF, and the AA metabolite pathway shows postoperative changes in centrifuged CSF pellets and supernatants.Item Open Access Impact of gene variants on sex-specific regulation of human Scavenger receptor class B type 1 (SR-BI) expression in liver and association with lipid levels in a population-based study.(BMC Med Genet, 2010-01-19) Chiba-Falek, Ornit; Nichols, Marshall; Suchindran, Sunil; Guyton, John; Ginsburg, Geoffrey S; Barrett-Connor, Elizabeth; McCarthy, Jeanette JBACKGROUND: Several studies have noted that genetic variants of SCARB1, a lipoprotein receptor involved in reverse cholesterol transport, are associated with serum lipid levels in a sex-dependent fashion. However, the mechanism underlying this gene by sex interaction has not been explored. METHODS: We utilized both epidemiological and molecular methods to study how estrogen and gene variants interact to influence SCARB1 expression and lipid levels. Interaction between 35 SCARB1 haplotype-tagged polymorphisms and endogenous estradiol levels was assessed in 498 postmenopausal Caucasian women from the population-based Rancho Bernardo Study. We further examined associated variants with overall and SCARB1 splice variant (SR-BI and SR-BII) expression in 91 human liver tissues using quantitative real-time PCR. RESULTS: Several variants on a haplotype block spanning intron 11 to intron 12 of SCARB1 showed significant gene by estradiol interaction affecting serum lipid levels, the strongest for rs838895 with HDL-cholesterol (p=9.2x10(-4)) and triglycerides (p=1.3x10(-3)) and the triglyceride:HDL cholesterol ratio (p=2.7x10(-4)). These same variants were associated with expression of the SR-BI isoform in a sex-specific fashion, with the strongest association found among liver tissue from 52 young women<45 years old (p=0.002). CONCLUSIONS: Estrogen and SCARB1 genotype may act synergistically to regulate expression of SCARB1 isoforms and impact serum levels of HDL cholesterol and triglycerides. This work highlights the importance of considering sex-dependent effects of gene variants on serum lipid levels.Item Open Access Lipid changes in the metabolome of a single case study with maple syrup urine disease (MSUD) after five days of improved diet adherence of controlled branched-chain amino acids (BCAA).(Molecular genetics and metabolism reports, 2020-12) Douglas, Teresa D; Newby, L Kristin; Eckstrand, Julie; Wixted, Douglas; Singh, Rani HBackground
Distinguishing systemic metabolic disruptions in maple syrup urine disease (MSUD) beyond amino acid pathways is under-investigated, yet important to understanding disease pathology and treatment options.Methods
An adolescent female (15 years) with MSUD without liver transplant, attended 2 study visits, 5 days apart. Medical diet adherence was determined based on her 3-day diet records and plasma branched-chain amino acid (BCAA) concentrations at both study visits. Plasma from a single age- and sex-matched control (MURDOCK Study, Duke University) and the case patient were analyzed with UPLC/MS/MS for intensity (m/z), annotated, and normalized against a median of 1 (Metabolon, Morrisville NC). Differences between case/control and 5-day comparisons were defined as ≥ ǀ 0.5 ǀ.Results
434 lipid metabolites were identified across samples; 90 (20.7%) were higher and 120 (27.6%) lower in the MSUD case at baseline compared with control. By study visit 2, plasma BCAA had declined, while 48 (53%) of elevated lipids and 14 (11.7%) of lower lipid values had moved to within ǀ 0.5 ǀ of control. Most shifts towards control by day 5 were seen in long-chain fatty acid intermediates (42%) and acylcarnitines (32%). Although androgenic (28%) and bile acid (23%) metabolites increased towards control, neither reached control level by day 5.Discussion
This comparative metabolomics study in a single MSUD case and healthy control suggests intrinsic differences in MSUD lipid metabolism potentially influenced by therapeutic diet. Findings suggest influences on hormone regulation, fatty acid oxidation, and bile acid synthesis, but further studies are needed to confirm an association between MSUD and lipid dysregulation.Synopsis
Within 5 days of improved dietary adherence, a single MSUD case experienced substantial changes in lipid markers potentially related to changes in plasma branched-chain amino acids.Item Open Access Metabolic Markers to Predict Incident Diabetes Mellitus in Statin-Treated Patients (from the Treating to New Targets and the Stroke Prevention by Aggressive Reduction in Cholesterol Levels Trials).(The American journal of cardiology, 2016-11) Kohli, Payal; Knowles, Joshua W; Sarraju, Ashish; Waters, David D; Reaven, GeraldThe goal of this analysis was to evaluate the ability of insulin resistance, identified by the presence of prediabetes mellitus (PreDM) combined with either an elevated triglyceride (TG >1.7 mmol/l) or body mass index (BMI ≥27.0 kg/m2), to identify increased risk of statin-associated type 2 diabetes mellitus (T2DM). Consequently, a retrospective analysis of data from subjects without diabetes in the Treating to New Targets and the Stroke Prevention by Aggressive Reduction in Cholesterol Levels randomized controlled trials was performed, subdividing participants into 4 experimental groups: (1) normal fasting glucose (NFG) and TG ≤1.7 mmol/l (42%); (2) NFG and TG >1.7 mmol/l (22%); (3) PreDM and TG ≤1.7 mmol/l (20%); and (4) PreDM and TG >1.7 mmol/l (15%). Comparable groupings were created substituting BMI values (kg/m2 <27.0 and ≥27.0) for TG concentrations. Patients received atorvastatin or placebo for a median duration of 4.9 years. Incident T2DM, defined by developing at least 2 fasting plasma glucose (FPG) concentrations ≥126 mg/dl, an increase in FPG ≥37 mg/dl, or a clinical diagnosis of T2DM, was observed in 8.2% of the total population. T2DM event rates (statin or placebo) varied from a low of 2.8%/3.2% (NFG and TG ≤1.7 mmol/l) to a high of 22.8%/7.6% (PreDM and TG >1.7 mmol/l) with intermediate values for only an elevated TG >1.7 mmol/l (5.2%/4.3%) or only PreDM (12.8%/7.6%). Comparable differences were observed when BMI values were substituted for TG concentrations. In conclusion, these data suggest that (1) the diabetogenic impact of statin treatment is relatively modest in general; (2) the diabetogenic impact is accentuated relatively dramatically as FPG and TG concentrations and BMI increase; and (3) PreDM, TG concentrations, and BMI identify people at highest risk of statin-associated T2DM.Item Open Access Novel Methods of Mycobacterial Control via Manipulation of Host Lipid Bioavailability(2020) McClean, Colleen MichelleLipids represent an important source of nutrition for infecting mycobacteria, accumulating within the necrotic core of granulomas and present in foamy macrophages associated with mycobacterial infection. In order to better understand the timing, process and importance of lipid accumulation, we developed methods for direct in vivo visualization and quantification of lipid accumulation using the zebrafish-M. marinum model of infection. We find that neutral lipids accumulate cell autonomously in mycobacterium-infected macrophages in vivo during early infection, with detectable levels of accumulation by two days post-infection. Reducing available free cholesterol and neutral lipids during early infection via treatment with ezetimibe, an FDA-approved drug, resulted in a reduction of bacterial growth in vivo. The effect of ezetimibe in reducing bacterial growth was dependent on the mce4 operon, a key bacterial determinant of lipid utilization. Thus, in vivo, lipid accumulation can occur cell autonomously at early timepoints of mycobacterial infection, and this early lipid accumulation confers a growth advantage to infecting mycobacteria.
This accumulation represents a perturbation of the normal homeostatic mechanisms by which intracellular lipids are tightly controlled. Under homeostatic conditions macrophages are central to the function of returning excess lipids to the liver where they are processed for excretion via the digestive tract. This function of macrophages, termed reverse cholesterol transport, results from the uptake of excess extracellular lipids, followed by the coordinated efflux of these lipids through the transport proteins ABCA1 and ABCG1 and packaging into HDL particles containing ApoAI and ApoAII. This process is controlled via the action of nuclear receptors including PPARγ, PPAR-α, and LXRα.
We performed RNA-seq analysis of gene expression in macrophages both uninfected and infected with mycobacteria and observed a profound down-regulation of all the major lipoproteins. The HDL associated lipoproteins ApoAI and ApoAII were the most profoundly down regulated. Based on this observation we sought to investigate the role of nuclear receptors involved in intracellular lipid sensing and control of apolipoprotein expression. We determined that agonism and antagonism of LXRα signaling decrease and increase infection burden during in vivo studies respectively. We further found that the ApoAI agonizing fibrate drugs fenofibrate and gemfibrozil reduce mycobacterial infection in vivo. This work demonstrates that lipid lowering agents already approved for use in humans might function as relevant adjuvant therapies toward treatment of mycobacterial infections.
Item Open Access Particulate allergens potentiate allergic asthma in mice through sustained IgE-mediated mast cell activation.(2010) Jin, CongIn recent years, the incidence of allergic asthma as well as the severity of disease has rapidly increased worldwide. Numerous epidemiological studies have related the exacerbation of allergic asthma with exposure to increased ambient particles from air pollutants. However, the mechanism by which particulate allergens (pAg) exacerbate allergic asthma remains undefined. To evaluate this, we modeled environmental pAg induced allergic asthma by exposing mice to polystyrene beads coated with natural allergen extracts. Compared to equal amounts of soluble allergen extracts (sAg), pAg triggered markedly enhanced airway hyper-responsiveness and pulmonary eosinophilia in allergen sensitized mice. The cellular basis for this effect was determined to be mast cells (MCs), as both airway allergic responses were attenuated in MC deficient KitWsh/KitW-sh mice compared to MC reconstituted KitW-sh/KitW-sh mice. The divergent responses of MCs to pAg versus sAg were due to differences in the termination rate of IgE/FcεRI initiated signaling. Following ligation of sAg, IgE/FcεRI rapidly shuttled into a degradative endosome/lysosome pathway. However, following ligation by pAg, IgE/FcεRI migrated into lipid raft enriched compartments and subsequently failed to follow a degradative pathway, which resulted in a prolonged signaling and heightened synthesis of proinflammatory mediators. These observations highlight the overlooked contributions of the particulate nature of allergens and mast cell endocytic circuitry to the aggravation of allergic asthma.Item Open Access PEDF Deletion Induces Senescence and Defects in Phagocytosis in the RPE.(International journal of molecular sciences, 2022-07) Rebustini, Ivan T; Crawford, Susan E; Becerra, S PatriciaThe retinal pigment epithelium (RPE) expresses the Serpinf1 gene to produce pigment epithelium-derived factor (PEDF), a retinoprotective protein that is downregulated with cell senescence, aging and retinal degenerations. We determined the expression of senescence-associated genes in the RPE of 3-month-old mice that lack the Serpinf1 gene and found that Serpinf1 deletion induced H2ax for histone H2AX protein, Cdkn1a for p21 protein, and Glb1 gene for β-galactosidase. Senescence-associated β-galactosidase activity increased in the Serpinf1 null RPE when compared with wild-type RPE. We evaluated the subcellular morphology of the RPE and found that ablation of Serpinf1 increased the volume of the nuclei and the nucleoli number of RPE cells, implying chromatin reorganization. Given that the RPE phagocytic function declines with aging, we assessed the expression of the Pnpla2 gene, which is required for the degradation of photoreceptor outer segments by the RPE. We found that both the Pnpla2 gene and its protein PEDF-R declined with the Serpinf1 gene ablation. Moreover, we determined the levels of phagocytosed rhodopsin and lipids in the RPE of the Serpinf1 null mice. The RPE of the Serpinf1 null mice accumulated rhodopsin and lipids compared to littermate controls, implying an association of PEDF deficiency with RPE phagocytosis dysfunction. Our findings establish PEDF loss as a cause of senescence-like changes in the RPE, highlighting PEDF as both a retinoprotective and a regulatory protein of aging-like changes associated with defective degradation of the photoreceptor outer segment in the RPE.Item Open Access Plasma lipoproteins of free-ranging howling monkeys (Alouatta palliata).(Comp Biochem Physiol B, 1987) Clark, SB; Tercyak, AM; Glander, KE1. Plasma lipids and lipoproteins of free-ranging howling monkeys from Costa Rica (Alouatta palliata), aged 5 months to 23 years, were characterized. 2. High density lipoproteins were lipid-rich, similar to HDL2 of human plasma. 3. Fatty acid compositions of major lipid classes of very low, low and high density lipoproteins differed among social groups, possibly due to both dietary and genetic factors. 4. Low and high density lipoprotein phospholipids were enriched in phosphatidylethanolamine. 5. Howler plasma cross reacted with antihuman apoA-I antibodies but not with antihuman LDL antibodies. 6. No dimeric form of apoA-II was present, unlike human apoA-II.Item Open Access Powerful, scalable and resource-efficient meta-analysis of rare variant associations in large whole genome sequencing studies.(Nature genetics, 2023-01) Li, Xihao; Quick, Corbin; Zhou, Hufeng; Gaynor, Sheila M; Liu, Yaowu; Chen, Han; Selvaraj, Margaret Sunitha; Sun, Ryan; Dey, Rounak; Arnett, Donna K; Bielak, Lawrence F; Bis, Joshua C; Blangero, John; Boerwinkle, Eric; Bowden, Donald W; Brody, Jennifer A; Cade, Brian E; Correa, Adolfo; Cupples, L Adrienne; Curran, Joanne E; de Vries, Paul S; Duggirala, Ravindranath; Freedman, Barry I; Göring, Harald HH; Guo, Xiuqing; Haessler, Jeffrey; Kalyani, Rita R; Kooperberg, Charles; Kral, Brian G; Lange, Leslie A; Manichaikul, Ani; Martin, Lisa W; McGarvey, Stephen T; Mitchell, Braxton D; Montasser, May E; Morrison, Alanna C; Naseri, Take; O'Connell, Jeffrey R; Palmer, Nicholette D; Peyser, Patricia A; Psaty, Bruce M; Raffield, Laura M; Redline, Susan; Reiner, Alexander P; Reupena, Muagututi'a Sefuiva; Rice, Kenneth M; Rich, Stephen S; Sitlani, Colleen M; Smith, Jennifer A; Taylor, Kent D; Vasan, Ramachandran S; Willer, Cristen J; Wilson, James G; Yanek, Lisa R; Zhao, Wei; NHLBI Trans-Omics for Precision Medicine (TOPMed) Consortium, TOPMed Lipids Working Group; Rotter, Jerome I; Natarajan, Pradeep; Peloso, Gina M; Li, Zilin; Lin, XihongMeta-analysis of whole genome sequencing/whole exome sequencing (WGS/WES) studies provides an attractive solution to the problem of collecting large sample sizes for discovering rare variants associated with complex phenotypes. Existing rare variant meta-analysis approaches are not scalable to biobank-scale WGS data. Here we present MetaSTAAR, a powerful and resource-efficient rare variant meta-analysis framework for large-scale WGS/WES studies. MetaSTAAR accounts for relatedness and population structure, can analyze both quantitative and dichotomous traits and boosts the power of rare variant tests by incorporating multiple variant functional annotations. Through meta-analysis of four lipid traits in 30,138 ancestrally diverse samples from 14 studies of the Trans Omics for Precision Medicine (TOPMed) Program, we show that MetaSTAAR performs rare variant meta-analysis at scale and produces results comparable to using pooled data. Additionally, we identified several conditionally significant rare variant associations with lipid traits. We further demonstrate that MetaSTAAR is scalable to biobank-scale cohorts through meta-analysis of TOPMed WGS data and UK Biobank WES data of ~200,000 samples.Item Open Access The effect of gemfibrozil, niacin and cholestyramine combination therapy on metabolic syndrome in the Armed Forces Regression Study.(Am J Med Sci, 2011-05) Krasuski, Richard A; Devendra, Ganesh P; Cater, George; Whitney, Edwin JINTRODUCTION: Metabolic syndrome is a powerful predictor of cardiovascular events independent of overt diabetes. Dietary restriction and weight loss modify metabolic syndrome components. This study addresses whether combination pharmacologic therapy focused on dyslipidemia provides additional benefit. METHODS: This study examines the effect of 1 year of gemfibrozil, niacin and cholestyramine therapy on a baseline of aggressive dietary and lifestyle intervention in 143 clinically stable, nondiabetic patients with coronary disease, randomized into a double-blind, placebo-controlled trial. RESULTS: Cohort characteristics included age 63 ± 7 years, 92% men, 43% with previous myocardial infarction, systolic blood pressure 139 ± 17 mm Hg, triglycerides 168 ± 81 mg/dL and high-density lipoprotein cholesterol 34 ± 6 mg/dL. The mean number of metabolic syndrome components decreased from 2.2 ± 0.9 to 1.5 ± 1.1, P < 0.001, and metabolic syndrome prevalence decreased from 38% to 18% (P < 0.001) for the entire cohort. In the lifestyle intervention and placebo group, the mean number of metabolic syndrome components decreased from 2.2 ± 0.9 to 1.9 ± 1.1 (P = 0.01), and prevalence of metabolic syndrome decreased from 44% to 30% (P = 0.15). A far more marked change was observed with lifestyle intervention and pharmacologic therapy: abnormal metabolic components decreased from 2.2 ± 0.9 to 1.0 ± 1.0 (P < 0.001), and prevalence of metabolic syndrome decreased from 32% to 6% (P < 0.001). CONCLUSIONS: The combination of gemfibrozil, niacin and cholestyramine has profound, beneficial effects on the components of metabolic syndrome. These benefits are additive to those seen with aggressive diet and lifestyle modification.Item Open Access The Importance of Considering Clinical Inertia and Implementation Science When Addressing Medication Adherence.(JAMA network open, 2020-10) Bosworth, Hayden BItem Open Access Track: A randomized controlled trial of a digital health obesity treatment intervention for medically vulnerable primary care patients.(Contemporary clinical trials, 2016-05) Foley, Perry; Steinberg, Dori; Levine, Erica; Askew, Sandy; Batch, Bryan C; Puleo, Elaine M; Svetkey, Laura P; Bosworth, Hayden B; DeVries, Abigail; Miranda, Heather; Bennett, Gary GIntroduction
Obesity continues to disproportionately affect medically vulnerable populations. Digital health interventions may be effective for delivering obesity treatment in low-resource primary care settings.Methods
Track is a 12-month randomized controlled trial of a digital health weight loss intervention in a community health center system. Participants are 351 obese men and women aged 21 to 65years with an obesity-related comorbidity. Track participants are randomized to usual primary care or to a 12-month intervention consisting of algorithm-generated tailored behavior change goals, self-monitoring via mobile technologies, daily self-weighing using a network-connected scale, skills training materials, 18 counseling phone calls with a Track coach, and primary care provider counseling. Participants are followed over 12months, with study visits at baseline, 6, and 12months. Anthropometric data, blood pressure, fasting lipids, glucose and HbA1C and self-administered surveys are collected. Follow-up data will be collected from the medical record at 24months.Results
Participants are 68% female and on average 50.7years old with a mean BMI of 35.9kg/m(2). Participants are mainly black (54%) or white (33%); 12.5% are Hispanic. Participants are mostly employed and low-income. Over 20% of the sample has hypertension, diabetes and hyperlipidemia. Almost 27% of participants currently smoke and almost 20% score above the clinical threshold for depression.Conclusions
Track utilizes an innovative, digital health approach to reduce obesity and chronic disease risk among medically vulnerable adults in the primary care setting. Baseline characteristics reflect a socioeconomically disadvantaged, high-risk patient population in need of evidence-based obesity treatment.Item Open Access Trade-off in the effects of the apolipoprotein E polymorphism on the ages at onset of CVD and cancer influences human lifespan.(Aging Cell, 2011-06) Kulminski, Alexander M; Culminskaya, Irina; Ukraintseva, Svetlana V; Arbeev, Konstantin G; Arbeeva, Liubov; Wu, Deqing; Akushevich, Igor; Land, Kenneth C; Yashin, Anatoli IProgress in unraveling the genetic origins of healthy aging is tempered, in part, by a lack of replication of effects, which is often considered a signature of false-positive findings. We convincingly demonstrate that the lack of genetic effects on an aging-related trait can be because of trade-offs in the gene action. We focus on the well-studied apolipoprotein E (APOE) e2/3/4 polymorphism and on lifespan and ages at onset of cardiovascular diseases (CVD) and cancer, using data on 3924 participants of the Framingham Heart Study Offspring cohort. Kaplan-Meier estimates show that the e4 allele carriers live shorter lives than the non-e4 allele carriers (log rank = 0.016). The adverse effect was attributed to the poor survival of the e4 homozygotes, whereas the effect of the common e3/4 genotype was insignificant. The e3/4 genotype, however, was antagonistically associated with onsets of those diseases predisposing to an earlier onset of CVD and a later onset of cancer compared to the non-e4 allele genotypes. This trade-off explains the lack of a significant effect of the e3/4 genotype on survival; adjustment for it in the Cox regression model makes the detrimental effect of the e4 allele highly significant (P = 0.002). This trade-off is likely caused by the lipid-metabolism-related (for CVD) and nonrelated (for cancer) mechanisms. An evolutionary rationale suggests that genetic trade-offs should not be an exception in studies of aging-related traits. Deeper insights into biological mechanisms mediating gene action are critical for understanding the genetic regulation of a healthy lifespan and for personalizing medical care.Item Open Access Uncovering a Novel Role of the Apoptotic Initiator Caspase, Caspase-2(2014) Segear Johnson, Erika LeeWith the prevalence of obesity and metabolic syndrome rising sharply world-wide, it has become increasingly important to define the molecular mechanisms underlying the pathogenesis and progression of diseases associated with lipid-induced cytotoxicity. Cardiovascular disease, type-2 diabetes mellitus, and nonalchoholic fatty liver disease (NAFLD) have all recently gained recognition as diseases that are exacerbated by lipoapoptosis. In this dissertation, we demonstrate a novel role for caspase-2 as an initiator of lipoapoptosis. Using an unbiased metabolomics approach, we discovered that the activation of caspase-2, the initiator of apoptosis in Xenopus egg extracts, is associated with an accumulation of long-chain fatty acid (LCFA) metabolites. Metabolic treatments that block the buildup of LCFAs potently inhibit caspase-2, while add-back of a saturated LCFA restores caspase activation in the extract setting. Extending these findings to mammalian cells, we show that caspase-2 is engaged and activated in response to treatment with the saturated LCFA, palmitate. Down-regulation of caspase-2 significantly impairs cell death induced by saturated LCFAs, revealing a conserved, critical role for caspase-2 in mediating LCFA-induced lipoapoptosis.
Since lipoapoptosis has been implicated as a key driver of the progression of NAFLD, we aimed to determine the therapeutic significance of our findings by evaluating the importance of caspase-2 in an in vivo model of this disease. We subjected wild-type and caspase-2 knockout mice to a diet which induces severe liver steatosis and the development nonalcoholic steatohepatitis (NASH), the most advanced stage of NAFLD characterized by liver fibrosis. Interestingly, we observed an increase in caspase-2 protein levels in the livers of wild-type mice fed a NASH-inducing diet. These findings were of particular importance, since caspase-2 expression was also significantly elevated in patients diagnosed with NASH. Most importantly, we demonstrated that caspase-2 knockout mice are protected from apoptosis and fibrosis when fed a NASH-inducing diet, suggesting that caspase-2 is major regulator of hepatocyte lipoapoptosis. Together, these findings reveal a previously unknown role for caspase-2 as an initiator of lipoapoptosis and suggest that caspase-2 may be an attractive therapeutic target for inhibiting pathological lipid-induced apoptosis.