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Benatzy Y, Palmer MA, Brüne B. Arachidonate 15-lipoxygenase type B: Regulation, function, and its role in pathophysiology. Front Pharmacol 2022; 13:1042420. [PMID: 36438817 PMCID: PMC9682198 DOI: 10.3389/fphar.2022.1042420] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/26/2022] [Indexed: 10/30/2023] Open
Abstract
As a lipoxygenase (LOX), arachidonate 15-lipoxygenase type B (ALOX15B) peroxidizes polyenoic fatty acids (PUFAs) including arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linoleic acid (LA) to their corresponding fatty acid hydroperoxides. Distinctive to ALOX15B, fatty acid oxygenation occurs with positional specificity, catalyzed by the non-heme iron containing active site, and in addition to free PUFAs, membrane-esterified fatty acids serve as substrates for ALOX15B. Like other LOX enzymes, ALOX15B is linked to the formation of specialized pro-resolving lipid mediators (SPMs), and altered expression is apparent in various inflammatory diseases such as asthma, psoriasis, and atherosclerosis. In primary human macrophages, ALOX15B expression is associated with cellular cholesterol homeostasis and is induced by hypoxia. Like in inflammation, the role of ALOX15B in cancer is inconclusive. In prostate and breast carcinomas, ALOX15B is attributed a tumor-suppressive role, whereas in colorectal cancer, ALOX15B expression is associated with a poorer prognosis. As the biological function of ALOX15B remains an open question, this review aims to provide a comprehensive overview of the current state of research related to ALOX15B.
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Affiliation(s)
- Yvonne Benatzy
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Frankfurt, Germany
| | - Megan A. Palmer
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Frankfurt, Germany
| | - Bernhard Brüne
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Frankfurt, Germany
- Frankfurt Cancer Institute, Goethe University Frankfurt, Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt, Frankfurt, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Frankfurt, Germany
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2
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Anderson MR, Shashaty MGS. The Impact of Obesity in Critical Illness. Chest 2021; 160:2135-2145. [PMID: 34364868 PMCID: PMC8340548 DOI: 10.1016/j.chest.2021.08.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/19/2021] [Accepted: 08/01/2021] [Indexed: 12/16/2022] Open
Abstract
The prevalence of obesity is rising worldwide. Adipose tissue exerts anatomic and physiological effects with significant implications for critical illness. Changes in respiratory mechanics cause expiratory flow limitation, atelectasis, and V̇/Q̇ mismatch with resultant hypoxemia. Altered work of breathing and obesity hypoventilation syndrome may cause hypercapnia. Challenging mask ventilation and peri-intubation hypoxemia may complicate intubation. Patients with obesity are at increased risk of ARDS and should receive lung-protective ventilation based on predicted body weight. Increased positive end expiratory pressure (PEEP), coupled with appropriate patient positioning, may overcome the alveolar decruitment and intrinsic PEEP caused by elevated baseline pleural pressure; however, evidence is insufficient regarding the impact of high PEEP strategies on outcomes. Venovenous extracorporeal membrane oxygenation may be safely performed in patients with obesity. Fluid management should account for increased prevalence of chronic heart and kidney disease, expanded blood volume, and elevated acute kidney injury risk. Medication pharmacodynamics and pharmacokinetics may be altered by hydrophobic drug distribution to adipose depots and comorbid liver or kidney disease. Obesity is associated with increased risk of VTE and infection; appropriate dosing of prophylactic anticoagulation and early removal of indwelling catheters may decrease these risks. Obesity is associated with improved critical illness survival in some studies. It is unclear whether this reflects a protective effect or limitations inherent to observational research. Obesity is associated with increased risk of intubation and death in SARS-CoV-2 infection. Ongoing molecular studies of adipose tissue may deepen our understanding of how obesity impacts critical illness pathophysiology.
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Affiliation(s)
- Michaela R Anderson
- Division of Pulmonary Disease and Critical Care Medicine, Columbia University
| | - Michael G S Shashaty
- Pulmonary, Allergy, and Critical Care Division and the Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania.
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Rezende FM, Rodriguez E, Leal-Gutiérrez JD, Elzo MA, Johnson DD, Carr C, Mateescu RG. Genomic Approaches Reveal Pleiotropic Effects in Crossbred Beef Cattle. Front Genet 2021; 12:627055. [PMID: 33815465 PMCID: PMC8017557 DOI: 10.3389/fgene.2021.627055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 02/22/2021] [Indexed: 12/13/2022] Open
Abstract
Carcass and meat quality are two important attributes for the beef industry because they drive profitability and consumer demand. These traits are of even greater importance in crossbred cattle used in subtropical and tropical regions for their superior adaptability because they tend to underperform compared to their purebred counterparts. Many of these traits are challenging and expensive to measure and unavailable until late in life or after the animal is harvested, hence unrealistic to improve through traditional phenotypic selection, but perfect candidates for genomic selection. Before genomic selection can be implemented in crossbred populations, it is important to explore if pleiotropic effects exist between carcass and meat quality traits. Therefore, the objective of this study was to identify genomic regions with pleiotropic effects on carcass and meat quality traits in a multibreed Angus-Brahman population that included purebred and crossbred animals. Data included phenotypes for 10 carcass and meat quality traits from 2,384 steers, of which 1,038 were genotyped with the GGP Bovine F-250. Single-trait genome-wide association studies were first used to investigate the relevance of direct additive genetic effects on each carcass, sensory and visual meat quality traits. A second analysis for each trait included all other phenotypes as covariates to correct for direct causal effects from identified genomic regions with pure direct effects on the trait under analysis. Five genomic windows on chromosomes BTA5, BTA7, BTA18, and BTA29 explained more than 1% of additive genetic variance of two or more traits. Moreover, three suggestive pleiotropic regions were identified on BTA10 and BTA19. The 317 genes uncovered in pleiotropic regions included anchoring and cytoskeletal proteins, key players in cell growth, muscle development, lipid metabolism and fat deposition, and important factors in muscle proteolysis. A functional analysis of these genes revealed GO terms directly related to carcass quality, meat quality, and tenderness in beef cattle, including calcium-related processes, cell signaling, and modulation of cell-cell adhesion. These results contribute with novel information about the complex genetic architecture and pleiotropic effects of carcass and meat quality traits in crossbred beef cattle.
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Affiliation(s)
- Fernanda M Rezende
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Eduardo Rodriguez
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Joel D Leal-Gutiérrez
- Psychiatry Department, University of California, San Diego, La Jolla, CA, United States
| | - Mauricio A Elzo
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Dwain D Johnson
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Chad Carr
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States
| | - Raluca G Mateescu
- Department of Animal Sciences, University of Florida, Gainesville, FL, United States
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Alipoor E, Hosseinzadeh-Attar MJ, Rezaei M, Jazayeri S, Chapman M. White adipose tissue browning in critical illness: A review of the evidence, mechanisms and future perspectives. Obes Rev 2020; 21:e13085. [PMID: 32608573 DOI: 10.1111/obr.13085] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/15/2020] [Accepted: 06/03/2020] [Indexed: 12/13/2022]
Abstract
Observational studies suggest better clinical outcomes following critical illness in patients with overweight and obesity (obesity paradox). An understanding of the morphologic, physiologic and metabolic changes in adipose tissue in critical illness may provide an explanation. Recent studies have demonstrated the transformation of white to brown-like adipocytes due to the "browning process," which has been of interest as a potential novel therapy in obesity during the last decade. The characteristics of the browning of white adipose tissue (WAT) include the appearance of smaller, multilocular adipocytes, increased UCP1 mRNA expression, mitochondrial density and respiratory capacity. These changes have been identified in some critical illnesses, which specifically refers to burns, sepsis and cancer cachexia in this study. The pathophysiological nature of WAT browning, underlying mechanisms, main regulators and potential benefits and harms of this process are interesting new areas that warrants further investigations. In this review, we discuss emerging scientific discipline of adipose tissue physiology in metabolic stress, available data, gaps of knowledge and future perspectives. Future investigations in this field may provide insights into the underlying mechanisms and clinical aspects of browning that may further our understanding of the proposed obesity paradox following critical illness, which may in turn open up opportunities for novel therapies to save lives and improve recovery.
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Affiliation(s)
- Elham Alipoor
- Department of Nutrition, School of Public Health, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Javad Hosseinzadeh-Attar
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.,Cardiac Primary Prevention Research Center (CPPRC), Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahsa Rezaei
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Shima Jazayeri
- Department of Nutrition, School of Public Health, Iran University of Medical Sciences, Tehran, Iran
| | - Marianne Chapman
- Discipline of Acute Care Medicine, School of Medicine, University of Adelaide, Adelaide, Australia.,Intensive Care Research Unit, Royal Adelaide Hospital, Adelaide, Australia.,National Health and Medical Research Council of Australia Centre for Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia
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Abstract
PURPOSE OF REVIEW To balance theoretical pros and cons of intermittent feeding, in light of the current nutritional management early during critical illness. RECENT FINDINGS Less aggressive nutrient administration is clinically superior in acute critical illness. This counterintuitive clinical finding may be explained by nutrient restriction activating autophagy, a process that clears intracellular damage. Intermittent feeding holds numerous theoretical benefits, such as activation of autophagy, preservation of the circadian rhythm, increased protein synthesis, and enhanced endogenous fatty acids release. RCTs investigating intermittent feeding in the ICU, however, are the most often limited to evaluation of gastrointestinal complications. Current guidelines advocate against the use of intermittent feeding, based on lack of benefit and increased risk of diarrhea, as revealed by a meta-analysis. SUMMARY Benefits of intermittent feeding in the ICU are today speculative, yet its potential impact may reach far beyond the gastrointestinal tract. Only adequately powered RCTs, evaluating both gastrointestinal tolerance, metabolic impact and patient-centered effects of intermittent feeding will allow to adopt or abort this nutritional strategy.
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Schetz M, De Jong A, Deane AM, Druml W, Hemelaar P, Pelosi P, Pickkers P, Reintam-Blaser A, Roberts J, Sakr Y, Jaber S. Obesity in the critically ill: a narrative review. Intensive Care Med 2019; 45:757-769. [PMID: 30888440 DOI: 10.1007/s00134-019-05594-1] [Citation(s) in RCA: 256] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/05/2019] [Indexed: 11/24/2022]
Abstract
The World Health Organization defines overweight and obesity as the condition where excess or abnormal fat accumulation increases risks to health. The prevalence of obesity is increasing worldwide and is around 20% in ICU patients. Adipose tissue is highly metabolically active, and especially visceral adipose tissue has a deleterious adipocyte secretory profile resulting in insulin resistance and a chronic low-grade inflammatory and procoagulant state. Obesity is strongly linked with chronic diseases such as type 2 diabetes, hypertension, cardiovascular diseases, dyslipidemia, non-alcoholic fatty liver disease, chronic kidney disease, obstructive sleep apnea and hypoventilation syndrome, mood disorders and physical disabilities. In hospitalized and ICU patients and in patients with chronic illnesses, a J-shaped relationship between BMI and mortality has been demonstrated, with overweight and moderate obesity being protective compared with a normal BMI or more severe obesity (the still debated and incompletely understood "obesity paradox"). Despite this protective effect regarding mortality, in the setting of critical illness morbidity is adversely affected with increased risk of respiratory and cardiovascular complications, requiring adapted management. Obesity is associated with increased risk of AKI and infection, may require adapted drug dosing and nutrition and is associated with diagnostic and logistic challenges. In addition, negative attitudes toward obese patients (the social stigma of obesity) affect both health care workers and patients.
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Affiliation(s)
- Miet Schetz
- Division of Cellular and Molecular Medicine, Clinical Department and Laboratory of Intensive Care Medicine, KU Leuven University, Herestraat 49, 3000, Leuven, Belgium.
| | - Audrey De Jong
- Anesthesia and Critical Care Department (DAR-B), Saint Eloi, University of Montpellier, Research Unit: PhyMedExp, INSERM U-1046, CNRS, 34295, Montpellier Cedex 5, France
| | - Adam M Deane
- Department of Medicine and Radiology, Melbourne Medical School, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia.,Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Parkville, VIC, Australia
| | - Wilfried Druml
- Klinik für Innere Medizin III, Abteilung für Nephrologie, Allgemeines Krankenhaus Wien, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - Pleun Hemelaar
- Department of Intensive Care Medicine (710), Radboud University Medical Centre, Geert Grooteplein Zuid 10, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy.,Anesthesia and Intensive Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, Genoa, Genoa, Italy
| | - Peter Pickkers
- Department of Intensive Care Medicine (710), Radboud University Medical Centre, Geert Grooteplein Zuid 10, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.,Radboud Center for Infectious Diseases, Nijmegen, The Netherlands
| | - Annika Reintam-Blaser
- Department of Intensive Care Medicine, Lucerne Cantonal Hospital, Lucerne, Switzerland.,Department of Anaesthesiology and Intensive Care, University of Tartu, Tartu, Estonia
| | - Jason Roberts
- University of Queensland Centre for Clinical Research, Faculty of Medicine, University of Queensland, Herston, Australia.,Centre for Translational Anti-infective Pharmacodynamics, School of Pharmacy, The University of Queensland, Woolloongabba, Australia.,Pharmacy Department, Royal Brisbane and Women's Hospital, Brisbane, Australia.,Departments of Intensive Care Medicine, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - Yasser Sakr
- Department of Anesthesiology and Intensive Care, Uniklinikum Jena, Jena, Germany
| | - Samir Jaber
- Anesthesia and Critical Care Department (DAR-B), Saint Eloi, University of Montpellier, Research Unit: PhyMedExp, INSERM U-1046, CNRS, 34295, Montpellier Cedex 5, France
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