Aortic Fibrosis in Insulin-Sensitive Mice with Endothelial Cell-Specific Deletion of Ceacam1 Gene

(1) Background: Mice with global Ceacam1 deletion developed plaque-like aortic lesions even on C57BL/6J background in the presence of increased endothelial cell permeability and insulin resistance. Loss of endothelial Ceacam1 gene caused endothelial dysfunction and reduced vascular integrity without affecting systemic insulin sensitivity. Because endothelial cell injury precedes atherosclerosis, we herein investigated whether the loss of endothelial Ceacam1 initiates atheroma formation in the absence of insulin resistance. (2) Methods: Endothelial cell-specific Ceacam1 null mice on C57BL/6J.Ldlr-/- background (Ldlr-/-VECadCre+Cc1fl/fl) were fed an atherogenic diet for 3-5 months before metabolic, histopathological, and en-face analysis of aortae were compared to their control littermates. Sirius Red stain was also performed on liver sections to analyze hepatic fibrosis. (3) Results: These mice displayed insulin sensitivity without significant fat deposition on aortic walls despite hypercholesterolemia. They also displayed increased inflammation and fibrosis. Deleting Ceacam1 in endothelial cells caused hyperactivation of VEGFR2/Shc/NF-κB pathway with resultant transcriptional induction of NF-κB targets. These include IL-6 that activates STAT3 inflammatory pathways, in addition to endothelin-1 and PDGF-B profibrogenic effectors. It also induced the association between SHP2 phosphatase and VEGFR2, downregulating the Akt/eNOS pathway and reducing nitric oxide production, a characteristic feature of endothelial dysfunction. Similarly, hepatic inflammation and fibrosis developed in Ldlr-/-VECadCre+Cc1fl/fl mice without an increase in hepatic steatosis. (4) Conclusions: Deleting endothelial cell Ceacam1 caused hepatic and aortic inflammation and fibrosis with increased endothelial dysfunction and oxidative stress in the presence of hypercholesterolemia. However, this did not progress into frank atheroma formation. Because these mice remained insulin sensitive, the study provides an in vivo demonstration that insulin resistance plays a critical role in the pathogenesis of frank atherosclerosis.

Regulation of hepatic fibrosis by carcinoembryonic antigen-related cell adhesion molecule 1

OBJECTIVE

NAFLD is a complex disease marked by cellular abnormalities leading to NASH. NAFLD patients manifest low hepatic levels of CEACAM1, a promoter of insulin clearance. Consistently, Cc1^-/- null mice displayed spontaneous hyperinsulinemia/insulin resistance and steatohepatitis. Liver-specific reconstitution of Ceacam1 reversed these metabolic anomalies in 8-month-old Cc1^-/-xliver+ mice fed a regular chow diet. The current study examined whether it would also reverse progressive hepatic fibrosis in mice fed a high-fat (HF) diet.

METHODS

3-Month-old mice were fed a high-fat diet for 3-5 months, and metabolic and histopathological analysis were conducted to evaluate their NASH phenotype.

RESULTS

Reconstituting CEACAM1 to Cc1^-/- livers curbed diet-induced liver dysfunction and NASH, including macrovesicular steatosis, lobular inflammation, apoptosis, oxidative stress, and chicken-wire bridging fibrosis. Persistence of hepatic fibrosis in HF-fed Cc1^-/- treated with nicotinic acid demonstrated a limited role for lipolysis and adipokine release in hepatic fibrosis caused by Ceacam1 deletion.

CONCLUSIONS

Restored metabolic and histopathological phenotype of HF-fed Cc1^{-/-xliver+xliver+} assigned a critical role for hepatic CEACAM1 in preventing NAFLD/NASH including progressive hepatic fibrosis.

Cone-beam CT versus Multidetector CT in Postoperative Cochlear Implant Imaging: Evaluation of Image Quality and Radiation Dose

BACKGROUND AND PURPOSE

Cone-beam CT is being increasingly used in head and neck imaging. We compared cone-beam CT with multidetector CT to assess postoperative implant placement and delineate finer anatomic structures, image quality, and radiation dose used.

MATERIALS AND METHODS

This retrospective multicenter study included 51 patients with cochlear implants and postoperative imaging via temporal bone cone-beam CT (n = 32 ears) or multidetector CT (n = 19 ears) between 2012 and 2017. We evaluated the visualization quality of single electrode contacts, the scalar position of the electrodes, cochlear walls, mastoid facial canal, metallic artifacts (using a 4-level visual score), and the ability to measure the insertion angle of the electrodes. The signal-to-noise ratio and radiation dose were also evaluated.

RESULTS

Cone-beam CT was more sensitive for visualizing the scalar position of the electrodes (P = .046), cochlear outer wall (P = .001), single electrode contacts (P < .001), and osseous spiral lamina (P = .004) and had fewer metallic artifacts (P < .001). However, there were no significant differences between both methods in visualization of the modiolus (P = .37), cochlear inner wall (P > .99), and mastoid facial canal wall (P = .07) and the ability to measure the insertion angle of the electrodes (P > .99). The conebeam CT group had significantly lower dose-length product (P < .001), but multidetector CT showed a higher signal-to-noise ratio in both bone and air (P = .22 and P = .001).

CONCLUSIONS

Cone-beam CT in patients with cochlear implants provides images with higher spatial resolution and fewer metallic artifacts than multidetector CT at a relatively lower radiation dose.

Loss of Hepatic Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 Links Nonalcoholic Steatohepatitis to Atherosclerosis

Patients with nonalcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) commonly develop atherosclerosis through a mechanism that is not well delineated. These diseases are associated with steatosis, inflammation, oxidative stress, and fibrosis. The role of insulin resistance in their pathogenesis remains controversial. Albumin (Alb)Cre⁺Cc1^flox(fl)/fl mice with the liver‐specific null deletion of the carcinoembryonic antigen‐related cell adhesion molecule 1 (Ceacam1; alias Cc1) gene display hyperinsulinemia resulting from impaired insulin clearance followed by hepatic insulin resistance, elevated de novo lipogenesis, and ultimately visceral obesity and systemic insulin resistance. We therefore tested whether this mutation causes NAFLD/NASH and atherosclerosis. To this end, mice were propagated on a low‐density lipoprotein receptor (Ldlr)^−/− background and at 4 months of age were fed a high‐cholesterol diet for 2 months. We then assessed the biochemical and histopathologic changes in liver and aortae. Ldlr^−/−AlbCre⁺Cc1^fl/fl mice developed chronic hyperinsulinemia with proatherogenic hypercholesterolemia, a robust proinflammatory state associated with visceral obesity, elevated oxidative stress (reduced NO production), and an increase in plasma and tissue endothelin‐1 levels. In parallel, they developed NASH (steatohepatitis, apoptosis, and fibrosis) and atherosclerotic plaque lesions. Mechanistically, hyperinsulinemia caused down‐regulation of the insulin receptor followed by inactivation of the insulin receptor substrate 1–protein kinase B–endothelial NO synthase pathway in aortae, lowering the NO level. This also limited CEACAM1 phosphorylation and its sequestration of Shc‐transforming protein (Shc), activating the Shc–mitogen‐activated protein kinase–nuclear factor kappa B pathway and stimulating endothelin‐1 production. Thus, in the presence of proatherogenic dyslipidemia, hyperinsulinemia and hepatic insulin resistance driven by liver‐specific deletion of Ceacam1 caused metabolic and vascular alterations reminiscent of NASH and atherosclerosis. Conclusion: Altered CEACAM1‐dependent hepatic insulin clearance pathways constitute a molecular link between NASH and atherosclerosis.

Loss of Ceacam1 promotes prostate cancer progression in Pten haploinsufficient male mice

OBJECTIVE

PTEN haploinsufficiency plays an important role in prostate cancer development in men. However, monoallelic deletion of Pten gene failed to induce high prostate intraepithelial neoplasia (PIN) until Pten^+/- mice aged or fed a high-calorie diet. Because CEACAM1, a cell adhesion molecule with a potential tumor suppression activity, is induced in Pten^+/- prostates, the study aimed at examining whether the rise of CEACAM1 limited neoplastic progression in Pten^+/- prostates.

METHODS

Pten^+/- were crossbred with Cc1^-/- mice harboring a null deletion of Ceacam1 gene to produce Pten^+/-/Cc1^-/- double mutants. Prostates from 7-month old male mice were analyzed histologically and biochemically for PIN progression.

RESULTS

Deleting Ceacam1 in Pten^+/- mice caused an early development of high-grade PIN in parallel to hyperactivation of PI3 kinase/Akt and Ras/MAP kinase pathways, with an increase in cell proliferation, epithelial-to-mesenchymal transition, angiogenesis and inflammation relative to Pten^+/- and Cc1^-/- individual mutants. It also caused a remarkable increase in lipogenesis in prostate despite maintaining insulin sensitivity. Concomitant Ceacam1 deletion with Pten^+/- activated the IL-6/STAT3 signaling pathways to suppress Irf-8 transcription that in turn, led to a decrease in the expression level of promyelocytic leukemia gene, a well characterized tumor suppressor in prostate.

CONCLUSIONS

Ceacam1 deletion accelerated high-grade prostate intraepithelial neoplasia in Pten haploinsufficient mice while preserving insulin sensitivity. This demonstrated that the combined loss of Ceacam1 and Pten advanced prostate cancer by increasing lipogenesis and modifying the STAT3-dependent inflammatory microenvironment of prostate.

SUN-079 Loss of Endothelial CEACAM1 Induces Atherogenic Fibrous Plaque Formation

Loss of Endothelial CEACAM1 Induces Atherogenic Fibrous Plaque Formation Carcinoembryonic antigen-related cell adhesion molecule1 (CEACAM1), a substrate of insulin and VEGF receptors, regulates insulin sensitivity by promoting hepatic insulin clearance. Global Ceacam1 gene deletion impaired insulin clearance to cause chronic hyperinsulinemia and peripheral insulin resistance [1]. It also caused spontaneous endothelial dysfunction and hypertension [2] in addition to atherogenic-like plaques in addition to lipid and macrophage deposition, as well as elevated leukocyte rolling and adhesion to the aortic wall in the absence of hypercholesterolemia and hypertriglyceridemia when the mutation was propagated on the C57BL/6 genetic background [3]. Because CEACAM1 promotes endothelial survival, vascular integrity, and pro-angiogenesis, we investigated the cell-autonomous role of endothelial cell CEACAM1 in the pathogenesis of atherosclerosis. To this aim, we generated endothelial cell CEACAM1 knockout mice and backcrossed them with low density lipoprotein receptor deficient mice (ldlr^–/– VECad+Cc1^fl/fl) prior to feeding them a high cholesterol diet for 3 months and characterizing both of their metabolic and vascular phenotypes. By comparison to ldlr^–/– mice, the mutants exhibited insulin sensitivity and moderate hypercholesterolemia. However, they exhibited decreased nitric oxide (NO) bioavailability with a reciprocal increase in plasma endothelin-1 and increased oxidative stress. The mutants also developed fibrotic plaques with elevated macrophage recruitment on the aortic wall without lipid deposition. We postulate that endothelin-1 contributes to fibrosis in these mice. Elevated endothelin-1 levels could stem from increased ras-MAPKinase signaling pathways in response to lower sequestration of Shc and increased coupling of Grb2 to insulin and VEGR in the absence of Ceacam1. Moreover, in the absence of Ceacam1, binding of Shp2 phosphatase to IRS1 increases to reduce IRS-1/Akt/eNOS activity and subsequently, lower NO production. Thus, the ldlr^–/– VECad+Cc1^fl/fl mouse can provide an in vivo system to delineate the endothelial cell-specific CEACAM1 effect on fibrosis independent of systemic risk factors. References: 1. DeAngelis, A.M., et al., Carcinoembryonic antigen-related cell adhesion molecule 1 - A link between insulin and lipid metabolism. Diabetes, 2008. 57(9): p. 2296-2303. 2. Russo, L., et al., Liver-specific rescuing of CEACAM1 reverses endothelial and cardiovascular abnormalities in male mice with null deletion of Ceacam1 gene. Mol Metab, 2018. 9: p. 98-113. 3. Najjar, S.M., et al., Ceacam1 deletion causes vascular alterations in large vessels. Am J Physiol Endocrinol Metab, 2013. 305(4): p. E519-29.

SAT-174 Loss of CEACAM1 in Endothelial Cells Causes Hepatic Fibrogenesis

Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 (CEACAM1) has been implicated in physiological processes in the metabolic as well as in the vascular systems, as supported by the cardiometabolic abnormalities associated with insulin resistance that developed in global Ceacam1 null mutants. Given the role of CEACAM1 in maintaining vascular integrity, we aimed at identifying a role for CEACAM1-dependent pathways in endothelial cells in the pathogenesis of hepatic fibrosis. To this end, we generated endothelial cell-specific Ceacam1 knockout mice (VECadCc1^-/-) and propagated them on the C57BL/6J genetic background. The mice remain insulin sensitive even at 12-months of age, as determined by hyperinsulinemic-euglycemic clamp analysis at 7 months and by insulin tolerance test. The mice display normoinsulinemia associated with intact insulin clearance and without hepatic steatosis. However, these VECadCc1^-/- mutants display inflammatory foci in liver parenchyma, when stained by H&E staining. This was supported by ~2-fold increase in the mRNA levels of genes involved in inflammation (F4/80, CD68, IL-1β IL-6, and TNF­α) and by immunostaining for macrophage pool (F4/80) and their activation (CD68). Sirius Red stain detected a remarkable chicken-­wire deposition of collagen fibers interstitially and in the perivenular region in livers of VECadCc1^-/- but not controls. The mRNA levels of profibrogenic markers (Tgfβ, collagen 1A1, collagen 6a3, and α-SMA) are ~2-fold higher than controls. Moreover, TGFβ1 is a basally activated in null mice, as shown by increased Smad2/3 phosphorylation compared to their controls. Several mechanisms could contribute to hepatic fibrosis in VECadCc1^-/- mutants. These include: 1) increased endothelial-to-mesenchymal transition, supported by increased expression of mesenchymal markers (Snail, Slug, and [fibroblast-specific protein1 (FSP1)] with a reciprocal decrease in endothelial cell makers (CD31) in mouse liver endothelial cells (MLEC) isolated from VECadCc1^-/- mice; 2) increased capillarization, a liver injury event that precedes fibrogenesis, as shown by the ~2-fold increase in the mRNA levels of markers of capillarization (Gli1, Gli2, Gli3, iNOS, and osteopontin) in hepatic primary endothelial cells; 3) elevated levels of plasma endothelin-1 (ET-1) that promotes fibrogenesis. Mechanistically, the rise in plasma ET-1 results from increased coupling of the Ras/MAPKinase pathway to insulin receptor and VEGFR via Shc, a Src homology 2 (SH2)-containing cytoplasmic adaptor protein that upon its binding to phosphorylated CEACAM1 undergoes sequestration. Thus, endothelial cell CEACAM1 plays a key role in preventing liver injury and resulting fibrogenesis.

Clinical significance of telomerase genes (hTERC and hTERT) amplification in patients with acute myeloid leukemia

Acute myeloid leukemia (AML) describes a heterogenous group of hematological disorders. Cytogenetic and molecular assays have allowed patients' follow up aiming for detection of minimal residual disease, prediction of patients' outcome, in addition to providing the rationale for designing novel molecular-targeted therapeutic strategies. Human telomerase reverse transcriptase (hTERT), encoded by the hTERT gene and the telomerase RNA component (hTERC) genes are frequently amplified in human tumors, which may indicate that the hTERT and the hTERC genes may be target for amplification during the transformation of human malignancies including hematological malignancies. This genetic event has implications in diagnosis, prognosis and therapeutics of cancer. To evaluate the hTERC and hTERT genes as a prognostic marker in patients with AML, hTERC and hTERT gene amplification was studied in 20 adult AML patients using a commercial FISH probes (Kreatech) designated to detect the copy numbers of the genes. They were 12 males and 8 females. Their ages ranged from 16 to 67 years. The patients were further divided into two groups; group I (12 patients) includes newly diagnosed AML patients and group II (8 patients) includes patients taken at 28th day of chemotherapy. The hTERC amplification was detected in 19/21 cases (90.5%). The copy number of the gene ranged from 2-5 copies per interphase cell. For the hTERT gene, the amplification was found in the same percent of the patients. The copy number of the gene ranged from 2-9 copies per interphase cell. On comparing the group I with group II there was a highly statistical significant difference regarding the percent of amplification of both genes. The percent of amplification of hTERT gene was found to be higher among patients with poor outcome of the disease than in patients with good outcome. On the contrary the hTERC gene amplification did not exhibit such a correlation. In conclusion, hTERT and hTERC genes amplification were detected in patients with AML; therefore telomerase can be a good cancer marker which may be involved in carcinogenesis of leukemia. Higher amplification was found in de novo cases than cases in remission which emphasize its role in clinical analysis, disease monitoring and detection of minimal residual disease.

KEYWORDS

Acute Myeloid leukemia, telomerase amplification, hTERC gene, hTERT gene.