Laparoscopic-Assisted Vaginal Hysterectomy With Dense Bladder Adhesions and Absent Cervix: A Case Report With a Descriptive Video of the Entire Procedure.

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.

Incorporating Augmented Reality Into Anatomy Education in a Contemporary Medical School Curriculum.

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.

Promoting cultural competency and osteopathic medicine awareness among premedical students through a summer premedical rural enrichment program.

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.

Integration of Nutrition Topics in Osteopathic Medical School Curriculum - Shared Experiences.

This article was migrated. The article was marked as recommended. A crucial component of osteopathic medicine's philosophy is self-regulation, preventive care, and health maintenance, including a healthy lifestyle. More than half of the osteopathic medical graduates pursue a career as primary care physicians, and as such patient education on healthy lifestyle, including eating habits, is a significant part of their daily practice. However, nutrition is often overlooked in the osteopathic medical school curricula. Therefore, strategic inclusion of evidence-based nutrition approaches will equip future osteopathic medical students with an understanding and application of nutrition to the ever-growing primary care medical profession. Working towards this goal, we are implementing nutritional science topics across the pre-clinical years of our new osteopathic medical school's curriculum. Providing nutrition topics that will fit into the systems-based curriculum may encourage other medical schools to enhance nutrition instruction in osteopathic medical education. Assimilating nutrition as a part of the curriculum will enhance osteopathic medical students' confidence to counsel and treat their future patient population.

Motivating High School Students From Rural Areas to Attend College and Pursue Careers as Osteopathic Physicians.

CONTEXT: One potential way to address critical current and future projected health care workforce shortages is through comprehensive programs that could potentially inspire high school students to pursue osteopathic medical careers in underserved areas. OBJECTIVE: To determine whether a comprehensive, 5-week enrichment program could promote interest among rural high-school students in careers osteopathic medicine. METHODS: In May 2018, 116 high school students with a grade point average of 2.8 or higher from rural areas, including New Mexico and its surrounding rural areas in the US-Mexico border region, enrolled in а 5-week program offering American College Testing (ACT) preparation and biomedical sciences enrichment at Burrell College of Osteopathic Medicine (BCOM). During the program, students were offered more than 150 hours of interactive in-class lectures and hands-on activities with laboratories focusing on college preparedness, health sciences, and motivating students to pursue osteopathic medical career and practice medicine in rural areas. Clinically-oriented sessions covering osteopathic philosophy and osteopathic manipulative medicine were included. After completion, a voluntary and anonymous survey was sent to students who completed the program students through QualtricsXM©. Blinded ACT scores were collected from participants' schools, along with college enrollment status information. RESULTS: Of 116 enrolled students, 106 (91.4%) completed the program successfully. In their postcompletion survey responses, students reported that they had gained a realistic perception of the field of medicine and were motivated to attend college (mean [standard error, SE] score on 5-point Likert scale over 2 questions, 4.8 [0.06]) and osteopathic medical school (mean [SE], 4.7 [0.1]). Participants also felt more informed about physician shortage in rural areas (mean [SE], 4.7 [0.07]) and appeared to be inspired to practice medicine in rural areas (mean [SE], 4.6 [0.09]). Students also reported feeling better prepared to take the ACT after finishing this program (mean [SE], 4.9 [0.04]). Finally, we were able to collect the ACT scores of 51 participants (48.1%) who completed the program; the mean ACT score was 24.3, compared with a reported national mean of 20.7 on a scoring scale of 1-36. We also performed a follow-up inquiry showing that 78 of the 81 participating students (96%) who had graduated from high school were enrolled in college or university and 59 (73%) had elected in science, technology, engineering, mathematics, or health majors. CONCLUSION: Rural high school pipeline programs could be a tool to motivate high school students to attend college and ultimately to develop physicians who are interested to practice in medically underserved areas.

Single Accreditation and The Match: How Does the Change Affect Osteopathic Graduates?

This article was migrated. The article was marked as recommended. There is a predicted serious shortage of physicians in the US. To overcome this problem, medical schools have expanded at the behest of the US Government by number and by overall graduates - both medical doctors and doctors of osteopathic medicine. However, the graduate medical program numbers are struggling to keep pace with the significant additional medical school graduates to adequately accommodate the larger supply of applicants for GME positions. Moreover, 2020 marks the first single accreditation system for graduate GME in the United States. Although a historical moment, it further contributes to the uncertainty of GME program availability and medical graduates match rates. In this article, we make a thorough analysis of traditional and recent matching rates for the American Association of Colleges of Osteopathic Medicine and the Accreditation Council for Graduate Medical Education programs for osteopathic medical graduates compared to medical school graduates and provide an insight of the 2020 single accreditation system match. Our data indicate that osteopathic medical graduates show increasing matching rates to previously ACGME programs, and the 2020 match shows the best matching rate so far.

Group V secretory phospholipase A2 enhances the progression of angiotensin II-induced abdominal aortic aneurysms but confers protection against angiotensin II-induced cardiac fibrosis in apoE-deficient mice.

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.

Group X secretory phospholipase A(2) augments angiotensin II-induced inflammatory responses and abdominal aortic aneurysm formation in apoE-deficient mice.

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.

Group X secretory phospholipase A2 regulates the expression of steroidogenic acute regulatory protein (StAR) in mouse adrenal glands.

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.

Bioactive products generated by group V sPLA(2) hydrolysis of LDL activate macrophages to secrete pro-inflammatory cytokines.

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.

The capacity of group V sPLA2 to increase atherogenicity of ApoE-/- and LDLR-/- mouse LDL in vitro predicts its atherogenic role in vivo.

OBJECTIVE: In vitro data indicate that human LDL modified by Group V secretory phospholipase A(2) (GV sPLA(2)) is proatherogenic. Consistent with this, gain and loss of function studies demonstrated that GV sPLA(2) promotes atherosclerosis in LDLR(-/-) mice. The current study investigates whether GV sPLA(2) promotes atherosclerotic processes in apoE(-/-) mice. METHODS AND RESULTS: LDL (d=1.019 to 1.063) from apoE(-/-) and LDLR(-/-) mice fed chow or Western diet were hydrolyzed by GV sPLA(2). Phosphatidylcholine on LDL from LDLR(-/-) mice fed either a chow or Western diet was hydrolyzed to a greater extent (61.1+/-0.4% and 45.3+/-4.6%) than the corresponding fractions from apoE(-/-) mice (41.7+/-3.6% and 39.4+/-1.2%). ApoE(-/-) LDL induced macrophage foam cell formation in vitro without modification by GV sPLA(2), whereas hydrolysis of LDLR(-/-) LDL was a prerequisite for foam cell formation. In contrast to findings in LDLR(-/-) mice, GV sPLA(2) deficiency did not significantly reduce atherosclerosis in apoE(-/-) mice, although collagen content was significantly reduced in lesions of apoE(-/-) mice lacking GV sPLA(2). CONCLUSIONS: The ability of GV sPLA(2) to promote atherosclerotic lipid deposition in apoE(-/-) and LDLR(-/-) mice may be related to its ability to increase the atherogenic potential of LDL from these mice as assessed in vitro.

Biology of secretory phospholipase A2.

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.

Syndecan-4 mediates macrophage uptake of group V secretory phospholipase A2-modified LDL.

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.

Acid Sphingomyelinase Deficiency Prevents Diet-induced Hepatic Triacylglycerol Accumulation and Hyperglycemia in Mice.

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.

Distinct mechanisms for OxLDL uptake and cellular trafficking by class B scavenger receptors CD36 and SR-BI.

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.

Group v secretory phospholipase A2 promotes atherosclerosis: evidence from genetically altered mice.

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.

Elevated sphingomyelinase activity and ceramide concentration in serum of patients undergoing high dose spatially fractionated radiation treatment: implications for endothelial apoptosis.

Spatially fractionated high dose (grid) radiation treatment (SFGRT) involves irradiation of bulky tumors with one high, grid-delivered, dose of 15 Gy followed by multiple consecutive doses of 2 Gy each. The goal of this study is to determine the effect of this treatment on serum ceramide content and to investigate possible involvement of ceramide in tumor regression after SFGRT. Serum ceramide and Secretory SMase (S-SMase) were quantified in 11 patients before and at 24, 48 and 72 h after the dose of 15 Gy. Furthermore, LDL particles were isolated from the serum and their apoptotic ability was tested in human endothelial cells by TUNEL assay. Sixty seven per cent (6/8) of the patients with partial (PR) or complete (CR) response showed statistically significant increase in serum ceramide levels. Of the nonresponders in the study, none showed an elevation in ceramide. S-SMase activity underwent similar changes. LDL particles from serum of patients collected 72 hours after SFGRT sensitized the endothelial cells to undergo apoptosis in response to 5 Gy radiation that by itself had only modest effect on cell death. Independent elevation of ceramide content of endothelial cells that were otherwise resistant to radiation-induced cell death also was sufficient to sensitize these cells to apoptosis. Serum S-SMase activity and ceramide content increase following SFGRT and correlate with the clinical response. Apparently, these changes are in the LDL-associated ceramide and may contribute to better tumor reduction after SFGRT, due to the ability of LDL-derived ceramide to sensitize endothelial cells for apoptosis.

Group V secretory phospholipase A2-modified low density lipoprotein promotes foam cell formation by a SR-A- and CD36-independent process that involves cellular proteoglycans.

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.

Group V sPLA2 hydrolysis of low-density lipoprotein results in spontaneous particle aggregation and promotes macrophage foam cell formation.

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.