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1.
Cureus ; 16(4): e57482, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38707153

RESUMO

Hysterectomy is one of the most frequently performed surgical procedures in the United States. Hysterectomy for benign gynecological reasons can be performed through several approaches: abdominal, laparoscopic, laparoscopically assisted vaginal, robotic-assisted, and vaginal natural orifice hysterectomy. The choice of approach is strongly influenced by factors such as previous procedures, safety, and recovery process. Currently, vaginal hysterectomy, laparoscopic-assisted vaginal hysterectomy (LAVH), assisted vaginal hysterectomy, and robotic-assisted vaginal hysterectomy are considered minimally invasive approaches with multiple benefits to the patient such as less trauma, shorter operative time, and shorter postoperative period. However, in patients with pelvic adhesions, adhesions within the abdominal cavity, especially omental adhesions to the abdominal wall, and adhesions between the uterus and the bladder caused by multiple cesarian sections or prior surgery on the cervix, these minimally invasive approaches are problematic. In this report, we describe in detail our approach to LAVH in a patient with severe abdominal adhesions and an absent cervix. We believe that our approach is safe and relatively fast compared to an open abdominal procedure and, therefore, it may help gynecologic surgeons-in-training nationwide.

2.
Cureus ; 16(4): e57443, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38699098

RESUMO

Anatomy education in the medical school curriculum has encountered considerable challenges during the last decade. The exponential growth of medical science has necessitated a review of the classical ways to teach anatomy to shorten the time students spend dissecting, allowing them to acquire critical, new knowledge in other disciplines. Augmented and mixed reality technologies have developed tremendously during the last few years, offering a wide variety of possibilities to deliver anatomy education to medical students. Here, we provide a methodology to develop, deliver, and assess an anatomy laboratory course using augmented reality applications. We suggest a novel approach, based on Microsoft® HoloLens II, to develop systematic sequences of holograms to reproduce human dissection. The laboratory sessions are prepared before classes and include a series of holograms revealing sequential layers of the human body, isolated structures, or a combination of structures forming a system or a functional unit. The in-class activities are conducted either as one group of students (n = 8-9) with a leading facilitator or small groups of students (n = 4) with facilitators (n = 4) joining the groups for discussion. The same or different sessions may be used for the assessment of students' knowledge. Although currently in its infancy, the use of holograms will soon become a substantial part of medical education. Currently, several companies are offering a range of useful learning platforms, from anatomy education to patient encounters. By describing the holographic program at our institution, we hope to provide a roadmap for other institutions looking to implement a systematic approach to teaching anatomy through holographic dissection. This approach has several benefits, including a sequential 3D presentation of the human body with varying layers of dissection, demonstrations of facilitator-selected three-dimensional (3D) anatomical regions or specific body units, and the option for classroom or remote facilitation, with the ability for students to review each session individually.

4.
J Osteopath Med ; 122(11): 553-561, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-35918806

RESUMO

CONTEXT: Premedical preparatory programs at osteopathic medical schools that recruit students from medically underserved areas (MUAs) may promote interest in practicing osteopathic medicine in underserved or rural areas. In these programs, emphasis on cultural competency may increase diversity among medical school applicants and decrease healthcare disparities in the future. OBJECTIVES: The goal of this study is to determine whether a summer premedical rural enrichment program (PREP) held at an osteopathic medical school located in a MUA will foster greater prioritization of cultural competency in medicine, enhance interest in practicing in rural or underserved areas, and increase familiarity with osteopathic medicine. METHODS: An eight-week summer PREP was hosted at the California Health Sciences University College of Osteopathic Medicine (CHSU-COM) in Clovis, California. Seventy-eight diverse participants were recruited from the Central Valley, an underserved region of California. Attendees were required to finish the formal application process and were recommended to have completed medical school prerequisite courses. The curriculum included Medical College Admission Test (MCAT) preparation through team-based learning sessions, introduction to the osteopathic medical school curriculum, osteopathic philosophy, and osteopathic manipulative medicine, as well as integrated anatomy and physiology sessions, medical school application workshops, mock interviews, simulation workshops, and sociology and cultural competency sessions. Data were collected via a voluntary and anonymous survey administered before and after the program with questions about familiarity with osteopathy, interest in practicing in underserved areas, medical school preparedness, and a post-course survey about cultural competency. The surveys had students rate statements on a Likert scale. RESULTS: Seventy-four of the 78 premedical students (95%) completed the pre-and postsurvey. There was a significant increase in agreement to statements evaluating medical school preparedness, osteopathic familiarity, and desire to practice medicine locally in the postprogram survey, compared to the preprogram survey. In the cultural competency postsurvey, 75.0% of the responses to questions that evaluated the positive effect of the course were "Agree" or "Strongly Agree." Of the reported postcourse outcomes, the average MCAT score was 504 ± 6.2 (38 students reported, 50.7%). Of the 27 participants who reported matriculation, 16 (59.2%) were admitted to osteopathic medical schools, 9 (33.3%) to allopathic medical schools, and 2 to other health programs. CONCLUSIONS: After completing the PREP program, premedical participants reported that they have better understanding of cultural competency and improvement in preparation for medical school, including familiarity with osteopathic medicine, and interest in serving MUAs. These findings indicate that similar programs may have a positive impact on MUAs. These programs may help create diverse and culturally competent osteopathic physicians.


Assuntos
Medicina Osteopática , Humanos , Medicina Osteopática/educação , Estudantes Pré-Médicos , Educação Pré-Médica , Competência Cultural , Faculdades de Medicina
5.
Am J Pathol ; 181(3): 1088-98, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22813854

RESUMO

Abdominal aortic aneurysms (AAAs) and heart failure are complex life-threatening diseases whose etiology is not completely understood. In this study, we investigated whether deficiency of group V secretory phospholipase A(2) (GV sPLA(2)) protects from experimental AAA. The impact of GV sPLA(2) deficiency on angiotensin (Ang) II-induced cardiac fibrosis was also investigated. Apolipoprotein E (apoE)(-/-) mice and apoE(-/-) mice lacking GV sPLA(2) (GV DKO) were infused with 1000 ng/kg per minute Ang II for up to 28 days. Increases in systolic blood pressure, plasma aldosterone level, and urinary and heart prostanoids were similar in apoE(-/-) and GV DKO mice after Ang II infusion. The incidence of aortic rupture in Ang II-infused GV DKO mice (10%) was significantly reduced compared with apoE(-/-) mice (29.4%). Although the incidence of AAA in GV DKO mice (81.3%) and apoE(-/-) mice (100%) was similar, the mean percentage increase in maximal luminal diameter of abdominal aortas was significantly smaller in GV DKO mice (68.5% ± 7.7%) compared with apoE(-/-) mice (92.6% ± 8.3%). Deficiency of GV sPLA(2) resulted in increased Ang II-induced cardiac fibrosis that was most pronounced in perivascular regions. Perivascular collagen, visualized by picrosirius red staining, was associated with increased TUNEL staining and increased immunopositivity for macrophages and myofibroblasts and nicotinamide adenine dinucleotide phosphate oxidase (NOX)-2 and NOX-4, respectively. Our findings indicate that GV sPLA(2) modulates pathological responses to Ang II, with different outcomes for AAA and cardiac fibrosis.


Assuntos
Aneurisma da Aorta Abdominal/enzimologia , Aneurisma da Aorta Abdominal/patologia , Apolipoproteínas E/deficiência , Progressão da Doença , Fosfolipases A2 do Grupo V/metabolismo , Miocárdio/patologia , Angiotensina II/administração & dosagem , Animais , Aneurisma da Aorta Abdominal/induzido quimicamente , Ruptura Aórtica/enzimologia , Ruptura Aórtica/patologia , Apolipoproteínas E/metabolismo , Apoptose/efeitos dos fármacos , Colágeno/metabolismo , Fibrose , Fosfolipases A2 do Grupo V/deficiência , Imuno-Histoquímica , Masculino , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Miocárdio/enzimologia , NADPH Oxidase 2 , NADPH Oxidase 4 , NADPH Oxidases/metabolismo , Prostaglandinas/metabolismo
6.
Atherosclerosis ; 214(1): 58-64, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20833395

RESUMO

OBJECTIVE: Abdominal aortic aneurysm (AAA) is a complex vascular disease characterized by matrix degradation and inflammation and is a major cause of mortality in older men. Specific interventions that prevent AAA progression remain to be identified. In this study, we tested the hypothesis that Group X secretory phospholipase A(2) (GX sPLA(2)), an enzyme implicated in inflammatory processes, mediates AAA. METHODS AND RESULTS: GX sPLA(2) was detected by immunostaining in human aneurysmal tissue and in angiotensin II (Ang II)-induced AAAs in apolipoprotein E-deficient (apoE(-/-)) mice. GX sPLA(2) mRNA was increased significantly (11-fold) in abdominal aortas of apoE(-/-) mice in response to Ang II infusion. To define the role of GX sPLA(2) in experimental AAAs, apoE(-/-) and apoE(-/-) x GX sPLA(2)(-/-) (GX DKO) mice were infused with Ang II for either 10 (n=7) or 28 (n=24-26) days. Deficiency of GX sPLA(2) significantly reduced the incidence and severity of AAAs, as assessed by ultrasound measurements in vivo of aortic lumens and by computer-assisted morphometric analyses ex vivo of external diameter. Results from gene expression profiling indicated that the expression of specific matrix metalloproteinases and inflammatory mediators was blunted in aortas from GX DKO mice compared to apoE(-/-) mice after 10-day Ang II infusion. Ang II induction of cyclooxygenase-2, interleukin-6, matrix metalloproteinase (MMP)-2, MMP-13 and MMP-14 was reduced significantly in GX DKO mice compared to apoE(-/-) mice. CONCLUSION: GX sPLA(2) promotes Ang II-induced pathological responses leading to AAA formation.


Assuntos
Angiotensina II/metabolismo , Aneurisma da Aorta Abdominal/metabolismo , Apolipoproteínas E/genética , Fosfolipases A2 do Grupo X/metabolismo , Animais , Aorta Abdominal/patologia , Apolipoproteínas E/metabolismo , Pressão Sanguínea , Humanos , Inflamação , Interleucinas/metabolismo , Metaloproteases/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos
7.
J Biol Chem ; 285(26): 20031-9, 2010 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-20421306

RESUMO

We developed C57BL/6 mice with targeted deletion of group X secretory phospholipase A(2) (GX KO). These mice have approximately 80% higher plasma corticosterone concentrations compared with wild-type (WT) mice under both basal and adrenocorticotropic hormone (ACTH)-induced stress conditions. This increased corticosterone level was not associated with increased circulating ACTH or a defect in the hypothalamic-pituitary axis as evidenced by a normal response to dexamethasone challenge. Primary cultures of adrenal cells from GX KO mice exhibited significantly increased corticosteroid secretion compared with WT cells. Conversely, overexpression of GX secretory phospholipase A(2) (sPLA(2)), but not a catalytically inactive mutant form of GX sPLA(2), significantly reduced steroid production 30-40% in Y1 mouse adrenal cell line. This effect was reversed by the sPLA(2) inhibitor, indoxam. Silencing of endogenous M-type receptor expression did not restore steroid production in GX sPLA(2)-overexpressing Y1 cells, ruling out a role for this sPLA(2) receptor in this regulatory process. Expression of steroidogenic acute regulatory protein (StAR), the rate-limiting protein in corticosteroid production, was approximately 2-fold higher in adrenal glands of GX KO mice compared with WT mice, whereas StAR expression was suppressed in Y1 cells overexpressing GX sPLA(2). Results from StAR-promoter luciferase reporter gene assays indicated that GX sPLA(2) antagonizes StAR promoter activity and liver X receptor-mediated StAR promoter activation. In summary, GX sPLA(2) is expressed in mouse adrenal glands and functions to negatively regulate corticosteroid synthesis, most likely by negatively regulating StAR expression.


Assuntos
Glândulas Suprarrenais/metabolismo , Regulação da Expressão Gênica , Fosfolipases A2 do Grupo X/genética , Fosfoproteínas/genética , Glândulas Suprarrenais/citologia , Glândulas Suprarrenais/efeitos dos fármacos , Hormônio Adrenocorticotrópico/sangue , Hormônio Adrenocorticotrópico/farmacologia , Animais , Linhagem Celular , Células Cultivadas , Corticosterona/sangue , Corticosterona/metabolismo , Feminino , Fosfolipases A2 do Grupo X/metabolismo , Imuno-Histoquímica , Luciferases/genética , Luciferases/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Fosfoproteínas/metabolismo , Progesterona/metabolismo , Regiões Promotoras Genéticas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transfecção
8.
Cytokine ; 50(1): 50-7, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20138782

RESUMO

OBJECTIVE: Previous studies have established that hydrolysis of LDL by Group V secretory phospholipase A(2) (GV sPLA(2)) generates a modified particle capable of inducing macrophage foam cell formation. The aim of the present study was to determine whether GV sPLA(2)-hydrolyzed LDL (GV-LDL) produces pro-atherogenic effects in macrophages independent of cholesterol accumulation. METHODS AND RESULTS: J-774 cells incubated with GV-LDL produced more TNF-alpha and IL-6 compared to cells incubated with control-LDL. Indirect immunofluorescence showed that GV-LDL but not control-LDL induced nuclear translocation of NFkappaB. Inhibitors of NFkappaB activation, effectively blocked cytokine production induced by GV-LDL. Control-LDL and GV-LDL were separated from albumin present in reaction mixtures by ultracentrifugation. The albumin fraction derived from GV-LDL contained 80% of the FFA generated and was more potent than the re-isolated GV-LDL in inducing pro-inflammatory cytokine secretion. Linoleic acid (18:2) and oleic acid (18:1) were the most abundant FFAs generated, whereas newly formed lyso-PCs contained 14:0 (myristic), 16:1 (palmitic), and 18:2 fatty acyl groups. Experiments with synthetic FFA showed that 18:1 induced J-774 cells to secrete TNF-alpha and IL-6. CONCLUSIONS: These results indicate that in addition to promoting atherosclerotic lipid accumulation in macrophages, GV sPLA(2) hydrolysis of LDL leads to activation of NFkappaB, a key regulator of inflammation.


Assuntos
LDL-Colesterol/metabolismo , Fosfolipases A2 do Grupo V/metabolismo , Mediadores da Inflamação/metabolismo , Interleucina-6/metabolismo , Ativação de Macrófagos , Macrófagos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Albuminas/metabolismo , Animais , Células COS , Núcleo Celular/metabolismo , Chlorocebus aethiops , Ácidos Graxos/metabolismo , Humanos , Hidrólise , Lipólise , Camundongos , NF-kappa B/antagonistas & inibidores , Ligação Proteica , Transporte Proteico
9.
J Biol Chem ; 284(13): 8359-68, 2009 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-19074137

RESUMO

Acid sphingomyelinase plays important roles in ceramide homeostasis, which has been proposed to be linked to insulin resistance. To test this association in vivo, acid sphingomyelinase deletion (asm(-/-)) was transferred to mice lacking the low density lipoprotein receptor (ldlr(-/-)), and then offsprings were placed on control or modified (enriched in saturated fat and cholesterol) diets for 10 weeks. The modified diet caused hypercholesterolemia in all genotypes; however, in contrast to asm(+/+)/ldlr(-/-), the acid sphingomyelinase-deficient littermates did not display hepatic triacylglyceride accumulation, although sphingomyelin and other sphingolipids were substantially elevated, and the liver was enlarged. asm(-/-)/ldlr(-/-) mice on a modified diet did not accumulate body fat and were protected against diet-induced hyperglycemia and insulin resistance. Experiments with hepatocytes revealed that acid sphingomyelinase regulates the partitioning of the major fatty acid in the modified diet, palmitate, into two competitive and inversely related pools, triacylglycerides and sphingolipids, apparently via modulation of serine palmitoyltransferase, a rate-limiting enzyme in de novo sphingolipid synthesis. These studies provide evidence that acid sphingomyelinase activity plays an essential role in the regulation of glucose metabolism by regulating the hepatic accumulation of triacylglycerides and sphingolipids during consumption of a diet rich in saturated fats.


Assuntos
Hepatócitos/enzimologia , Hiperglicemia/enzimologia , Fígado/enzimologia , Serina C-Palmitoiltransferase/metabolismo , Esfingomielina Fosfodiesterase/deficiência , Triglicerídeos/metabolismo , Animais , Alimentos Formulados/efeitos adversos , Glucose/metabolismo , Hiperglicemia/induzido quimicamente , Resistência à Insulina/genética , Camundongos , Camundongos Knockout , Palmitatos/metabolismo , Receptores de LDL/genética , Receptores de LDL/metabolismo , Serina C-Palmitoiltransferase/genética , Esfingolipídeos/metabolismo , Esfingomielina Fosfodiesterase/metabolismo , Triglicerídeos/genética
10.
J Lipid Res ; 50(4): 641-50, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19056705

RESUMO

We previously reported that LDL modified by group V secretory phospholipase A2 (GV-LDL) promotes macrophage foam cell formation through a mechanism independent of scavenger receptors SR-A and CD36, and dependent on cellular proteoglycans. This study investigates the role of syndecans, a family of cell surface proteoglycans known to mediate endocytosis through macropinocytosis, in macrophage uptake of GV-LDL. LY 294002, a phosphatidylinositol 3-kinase inhibitor, significantly reduced internalization of (125)I-labeled GV-LDL in J-774 macrophages, consistent with a macropinocytic uptake pathway. Using small, interfering RNA-directed gene silencing, we demonstrated a direct relationship between (125)I-labeled GV-LDL binding and the level of syndecan-3 and syndecan-4 expression in J-774 cells. However, (125)I-labeled GV-LDL uptake was significantly reduced only when syndecan-4 expression was suppressed. Peritoneal macrophages from syndecan-4-deficient mice exhibited markedly reduced uptake of fluorescently labeled GV-LDL compared with wild-type cells. Furthermore, cholesteryl ester accumulation induced by GV-LDL was dependent on syndecan-4 expression. Syndecan-4 expression and GV-LDL binding were significantly increased in J-774 cells treated with lipopolysaccharide, suggesting that GV-LDL uptake via this pathway may be enhanced during inflammation. Taken together, our data point to a novel role for syndecan-4 in mediating the uptake of GV-LDL, a process implicated in atherosclerotic lesion progression.


Assuntos
Fosfolipases A2 do Grupo V/metabolismo , Lipoproteínas LDL/metabolismo , Macrófagos Peritoneais/metabolismo , Sindecana-4/metabolismo , Animais , Aterosclerose/etiologia , Aterosclerose/metabolismo , Sequência de Bases , Transporte Biológico Ativo/efeitos dos fármacos , Linhagem Celular , Células Cultivadas , Cromonas/farmacologia , Primers do DNA/genética , Expressão Gênica , Macrófagos Peritoneais/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Morfolinas/farmacologia , Pinocitose/efeitos dos fármacos , Interferência de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , Sindecana-3/metabolismo , Sindecana-4/deficiência , Sindecana-4/genética
11.
Cardiovasc Drugs Ther ; 23(1): 61-72, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18853244

RESUMO

INTRODUCTION: The secretory phospholipase A(2) (sPLA(2)) family provides a seemingly endless array of potential biological functions that is only beginning to be appreciated. In humans, this family comprises 9 different members that vary in their tissue distribution, hydrolytic activity, and phospholipid substrate specificity. Through their lipase activity, these enzymes trigger various cell-signaling events to regulate cellular functions, directly kill bacteria, or modulate inflammatory responses. In addition, some sPLA(2)'s are high affinity ligands for cellular receptors. OBJECTIVE: This review merely scratches the surface of some of the actions of sPLA(2)s in innate immunity, inflammation, and atherosclerosis. The goal is to provide an overview of recent findings involving sPLA(2)s and to point to potential pathophysiologic mechanisms that may become targets for therapy.


Assuntos
Imunidade Inata/fisiologia , Inflamação/fisiopatologia , Fosfolipases A2 Secretórias/metabolismo , Animais , Aterosclerose/tratamento farmacológico , Aterosclerose/fisiopatologia , Sistemas de Liberação de Medicamentos , Humanos , Inflamação/tratamento farmacológico , Ligantes , Transdução de Sinais
12.
J Lipid Res ; 48(12): 2560-70, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17876058

RESUMO

Modified forms of LDL, including oxidized low density lipoprotein (OxLDL), contribute to macrophage lipid accumulation in the vessel wall. Despite the pathophysiological importance of uptake pathways for OxLDL, the molecular details of OxLDL endocytosis by macrophages are not well understood. Studies in vitro demonstrate that the class B scavenger receptor CD36 mediates macrophage uptake and degradation of OxLDL. Although the closely related scavenger receptor class B type I (SR-BI) binds OxLDL with high affinity, evidence that SR-BI plays a role in OxLDL metabolism is lacking. In this study, we directly compared OxLDL uptake and degradation by CD36 and SR-BI. Our results indicate that although CD36 and SR-BI internalize OxLDL, SR-BI mediates significantly less OxLDL degradation. Endocytosis of OxLDL by both SR-BI and CD36 is independent of caveolae, microtubules, and actin cytoskeleton. However, OxLDL uptake by CD36, but not SR-BI, is dependent on dynamin. The analysis of chimeric SR-BI/CD36 receptors shows that the CD36 C-terminal cytoplasmic tail is necessary and sufficient for dynamin-dependent OxLDL internalization by class B scavenger receptors. These findings indicate that different mechanisms are involved in OxLDL uptake by SR-BI and CD36, which may segregate these two structurally homologous receptors at the cell surface, leading to differences in intracellular trafficking and degradation.


Assuntos
Antígenos CD36/metabolismo , Lipoproteínas LDL/metabolismo , Actinas/metabolismo , Animais , Transporte Biológico , Células COS , Cavéolas/metabolismo , Chlorocebus aethiops , Citoplasma/metabolismo , Dinaminas/metabolismo , Endocitose , Lisossomos/metabolismo , Microscopia de Fluorescência , Microtúbulos/metabolismo , Ratos , Transferrina/metabolismo
13.
Arterioscler Thromb Vasc Biol ; 27(3): 600-6, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17204667

RESUMO

OBJECTIVE: Group V secretory phospholipase A2 (GV sPLA2) has been detected in both human and mouse atherosclerotic lesions. This enzyme has potent hydrolytic activity towards phosphatidylcholine-containing substrates, including lipoprotein particles. Numerous studies in vitro indicate that hydrolysis of high density lipoproteins (HDL) and low density lipoproteins (LDL) by GV sPLA2 leads to the formation of atherogenic particles and potentially proinflammatory lipid mediators. However, there is no direct evidence that this enzyme promotes atherogenic processes in vivo. METHODS AND RESULTS: We performed gain-of-function and loss-of-function studies to investigate the role of GV sPLA2 in atherogenesis in LDL receptor-deficient mice. Compared with control mice, animals overexpressing GV sPLA2 by retrovirus-mediated gene transfer had a 2.7 fold increase in lesion area in the ascending region of the aortic root. Increased atherosclerosis was associated with an increase in lesional collagen deposition in the same region. Mice deficient in bone marrow-derived GV sPLA2 had a 36% reduction in atherosclerosis in the aortic arch/thoracic aorta. CONCLUSIONS: Our data in mouse models provide the first in vivo evidence that GV sPLA2 contributes to atherosclerotic processes, and draw attention to this enzyme as an attractive target for the treatment of atherosclerotic disease.


Assuntos
Aterosclerose/enzimologia , Fosfolipases A/metabolismo , Receptores de LDL/deficiência , Animais , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica , Fosfolipases A2 do Grupo V , Metabolismo dos Lipídeos/fisiologia , Lipoproteínas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fosfolipases A/genética , Fosfolipases A2 , Valores de Referência , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade
14.
J Biol Chem ; 280(38): 32746-52, 2005 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-16040605

RESUMO

Accumulating evidence indicates that secretory phospholipase A2 (sPLA2) enzymes promote atherogenic processes. We have previously showed the presence of Group V sPLA2 (GV sPLA2) in human and mouse atherosclerotic lesions, its hydrolysis of low density lipoprotein (LDL) particles, and the ability of GV sPLA2-modified LDL (GV-LDL) to induce macrophage foam cell formation in vitro. The goal of this study was to investigate the mechanisms involved in macrophage uptake of GV-LDL. Peritoneal macrophages from C57BL/6 mice (wild type (WT)), C57BL/6 mice deficient in LDL receptor (LDLR-/-), or SR-A and CD36 (DKO) were treated with control LDL, GV-LDL, oxidized LDL (ox-LDL) or LDL aggregated by vortexing (vx-LDL). As expected, ox-LDL induced significantly more cholesterol ester accumulation in WT and LDLR-/- compared with DKO macrophages. In contrast, there was no difference in the accumulation of GV-LDL or vx-LDL in the three cell types. 125I-ox-LDL exhibited high affinity, saturable binding to WT cells that was significantly reduced in DKO cells. Vx-LDL and GV-LDL showed low affinity, non-saturable binding that was similar for both cell types, and significantly higher compared with control LDL. GV-LDL degradation in WT and DKO cells was similar. Analyses by confocal microscopy indicated a distinct intracellular distribution of Alexa-568-labeled GV-LDL and Alexa-488-labeled ox-LDL. Uptake of GV-LDL (but not ox-LDL or vx-LDL) was significantly reduced in cells preincubated with heparin or NaClO3, suggesting a role for proteoglycans in GV-LDL uptake. Our data point to a physiological modification of LDL that has the potential to promote macrophage foam cell formation independent of scavenger receptors.


Assuntos
Antígenos CD36/biossíntese , Células Espumosas/metabolismo , Lipoproteínas LDL/metabolismo , Fosfolipases A/metabolismo , Proteoglicanas/metabolismo , Animais , Compostos Azo/farmacologia , Ésteres do Colesterol/metabolismo , Corantes/farmacologia , Cruzamentos Genéticos , Feminino , Corantes Fluorescentes/farmacologia , Fosfolipases A2 do Grupo V , Heparina/metabolismo , Humanos , Hidrazinas/farmacologia , Hidrólise , Metabolismo dos Lipídeos , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Modelos Moleculares , Peritônio/metabolismo , Fosfolipases A2 , Ligação Proteica , Transfecção
15.
Arterioscler Thromb Vasc Biol ; 24(4): 762-7, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-14962950

RESUMO

OBJECTIVE: Secretory phospholipase A2 (sPLA2) enzymes hydrolyze the sn-2 fatty acyl ester bond of phospholipids to produce a free fatty acid and a lysophospholid. Group V sPLA2 is expressed in cultured macrophage cells and has high affinity for phosphatidyl choline-containing substrates. The present study assesses the presence of group V sPLA2 in human and mouse atherosclerotic lesions and its activity toward low-density lipoprotein (LDL) particles. METHODS AND RESULTS: Group V sPLA2 was detected in human and mouse atherosclerotic lesions by immunohistochemical staining. Electron microscopic analysis showed that mouse group V sPLA2-modified LDL is significantly smaller (mean diameter+/-SEM=25.3+/-0.25 nm) than native LDL (mean diameter+/-SEM=27.7+/-0.29 nm). Hydrolysis by group V sPLA2 induced spontaneous particle aggregation; the extent of aggregation was directly proportional to the degree of LDL hydrolysis. Group V sPLA2 modification of LDL led to enhanced lipid accumulation in cultured mouse peritoneal macrophage cells. CONCLUSIONS: Group V sPLA2 may play an important role in promoting atherosclerotic lesion development by modifying LDL particles in the arterial wall, thereby enhancing particle aggregation, retention, and macrophage uptake.


Assuntos
Doenças da Aorta/enzimologia , Arteriosclerose/enzimologia , Lipoproteínas LDL/metabolismo , Fosfolipases A/metabolismo , Sequência de Aminoácidos , Animais , Doenças da Aorta/fisiopatologia , Arteriosclerose/fisiopatologia , Células COS/enzimologia , Chlorocebus aethiops , Fosfolipases A2 do Grupo II , Humanos , Hidrólise , Lipoproteínas LDL/química , Macrófagos Peritoneais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica , Dados de Sequência Molecular , Fosfolipases A/genética , Fosfolipases A2 , Proteínas Recombinantes de Fusão/fisiologia , Especificidade por Substrato
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