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Diabetes is associated with decreased epoxyeicosatrienoic acids (EET) bioavailability and increased levels of glomerular vascular endothelial growth factor A (VEGF-A) expression. We examined whether a soluble epoxide hydrolase (sEH) inhibitor protects against pathologic changes in diabetic kidney disease and whether the inhibition of VEGF-A signaling pathway attenuates diabetes-induced glomerular injury. We also aimed to delineate the crosstalk between cytochrome P450 2C (CYP2C)-derived EETs and VEGF-A. Streptozotocin (STZ)-induced type 1 diabetic (T1D) rats were treated with 25 mg/L of AUDA in drinking water for 6 weeks. In parallel experiments, T1D rats were treated with either SU5416 or humanized monoclonal anti-VEGF-A neutralizing antibody for 8 weeks. Following treatment, the rats were euthanized, and kidney cortices were isolated for further analysis. Treatment with AUDA attenuated the diabetes-induced decline in kidney function. Furthermore, treatment with AUDA decreased diabetes-associated oxidative stress and NADPH oxidase activity. Interestingly, the downregulation of CYP2C11-derived EET formation is found to be correlated with the activation of VEGF-A signaling pathway. In fact, inhibiting VEGF-A using anti-VEGF or SU5416 markedly attenuated diabetes-induced glomerular injury through the inhibition of Nox4-induced ROS production. These findings were replicated in vitro in rat and human podocytes cultured in a diabetic milieu. Taken together, our results indicate that hyperglycemia-induced glomerular injury is mediated by the downregulation of CYP2C11-derived EET formation, followed by the activation of the VEGF-A signaling and upregulation of Nox4. To our knowledge, this is the first study to highlight VEGF-A as a mechanistic link between CYP2C11-derived EET production and Nox4.

The year 2021 marked the centenary of the discovery of insulin [...]

(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.

CEACAM1 regulates endothelial barrier integrity. Because insulin signaling in extrahepatic target tissues is regulated by insulin transport through the endothelium, we aimed at investigating the metabolic role of endothelial CEACAM1. To this end, we generated endothelial cell-specific Ceacam1 null mice (VECadCre+Cc1fl/fl) and carried out their metabolic phenotyping and mechanistic analysis by comparison to littermate controls. Hyperinsulinemic-euglycemic clamp analysis showed intact insulin sensitivity in VECadCre+Cc1fl/fl mice. This was associated with the absence of visceral obesity and lipolysis and normal levels of circulating non-esterified fatty acids, leptin, and adiponectin. Whereas the loss of endothelial Ceacam1 did not affect insulin-stimulated receptor phosphorylation, it reduced IRS-1/Akt/eNOS activation to lower nitric oxide production resulting from limited SHP2 sequestration. It also reduced Shc sequestration to activate NF-κB and increase the transcription of matrix metalloproteases, ultimately inducing plasma IL-6 and TNFα levels. Loss of endothelial Ceacam1 also induced the expression of the anti-inflammatory CEACAM1-4L variant in M2 macrophages in white adipose tissue. Together, this could cause endothelial barrier dysfunction and facilitate insulin transport, sustaining normal glucose homeostasis and retaining fat accumulation in adipocytes. The data assign a significant role for endothelial cell CEACAM1 in maintaining insulin sensitivity in peripheral extrahepatic target tissues.

Oxidative damage by reactive oxygen species (ROS) is one of the main contributors to cell injury and tissue damage in thalassemia patients. Recent studies suggest that ROS generation in non-transfusion-dependent (NTDT) patients occurs as a result of iron overload. Among the different sources of ROS, the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family of enzymes and cytochrome P450 (CYP450) have been proposed to be major contributors for oxidative stress in several diseases. However, the sources of ROS in patients with NTDT remain poorly understood. In this study, Hbbth3/+ mice, a mouse model for β-thalassemia, were used. These mice exhibit an unchanged or decreased expression of the major NOX isoforms, NOX1, NOX2 and NOX4, when compared to their C57BL/6 control littermates. However, a significant increase in the protein synthesis of CYP4A and CYP4F was observed in the Hbbth3/+ mice when compared to the C57BL/6 control mice. These changes were paralleled by an increased production of 20-hydroxyeicosatetraenoic acid (20-HETE), a CYP4A and CYP4F metabolite. Furthermore, these changes corroborate with onset of ROS production concomitant with liver injury. To our knowledge, this is the first report indicating that CYP450 4A and 4F-induced 20-HETE production mediates reactive oxygen species overgeneration in Hbbth3/+ mice through an NADPH-dependent pathway.

The study was partially presented as a poster in the 53rd Annual Meeting of the European Association for the Study of Diabetes, Lisbon 2017., The role of insulin-degrading enzyme (IDE), a metalloprotease with high affinity for insulin, in insulin clearance remains poorly understood. OBJECTIVE: This study aimed to clarify whether IDE is a major mediator of insulin clearance, and to define its role in the etiology of hepatic insulin resistance., [Methods] We generated mice with liver-specific deletion of Ide (L-IDE-KO) and assessed insulin clearance and action., [Results] L-IDE-KO mice exhibited higher (~20%) fasting and non-fasting plasma glucose levels, glucose intolerance and insulin resistance. This phenotype was associated with ~30% lower plasma membrane insulin receptor levels in liver, as well as ~55% reduction in insulin-stimulated phosphorylation of the insulin receptor, and its downstream signaling molecules, AKT1 and AKT2 (reduced by ~40%). In addition, FoxO1 was aberrantly distributed in cellular nuclei, in parallel with up-regulation of the gluconeogenic genes Pck1 and G6pc. Surprisingly, L-IDE-KO mice showed similar plasma insulin levels and hepatic insulin clearance as control mice, despite reduced phosphorylation of the carcinoembryonic antigen-related cell adhesion molecule 1, which upon its insulin-stimulated phosphorylation, promotes receptor-mediated insulin uptake to be degraded., [Conclusion] IDE is not a rate-limiting regulator of plasma insulin levels in vivo., This work was supported by grants from the Ministerio de Economía, Industria y Competitividad: SAF2014-58702-C2-1-R and SAF2016-77871-C2-1-R to ICC; SAF2014-58702-C2-2-R and SAF2016-77871-C2-2-R to GP; supported by the EFSD European Research Programme on New Targets for Type 2 Diabetes supported by an educational research grant from MSD to ICC and GP; the National Institutes of Health: R01-DK054254, R01-DK083850 and RO1-HL-112248 to SMN, and R01-GM115617 to MAL; and the American Diabetes Association: Career Development Award 7-11-CD-13 to MAL.

Exenatide, a glucagon‐like peptide‐1 receptor agonist, induces insulin secretion. Its role in insulin clearance has not been adequately examined. Carcinoembryonic antigen‐related cell adhesion molecule 1 (CEACAM1) promotes hepatic insulin clearance to maintain insulin sensitivity. Feeding C57BL/6J mice a high‐fat diet down‐regulates hepatic Ceacam1 transcription to cause hyperinsulinemia, insulin resistance, and hepatic steatosis, as in Ceacam1 null mice (Cc1 –/–). Thus, we tested whether exenatide regulates Ceacam1 expression in high‐fat diet‐fed mice and whether this contributes to its insulin sensitizing effect. Exenatide (100 nM) induced the transcriptional activity of wild‐type Ceacam1 promoter but not the constructs harboring block mutations of peroxisome proliferator‐activated receptor response element and retinoid X receptor alpha, individually or collectively, in HepG2 human hepatoma cells. Chromatin immunoprecipitation analysis demonstrated binding of peroxisome proliferator‐activated receptor gamma to Ceacam1 promoter in response to rosiglitazone and exenatide. Consistently, exenatide induced Ceacam1 messenger RNA expression within 12 hours in the absence but not in the presence of the glucagon‐like peptide‐1 receptor antagonist exendin 9‐39. Exenatide (20 ng/g body weight once daily intraperitoneal injection in the last 30 days of feeding) restored hepatic Ceacam1 expression and insulin clearance to curb diet‐induced metabolic abnormalities and steatohepatitis in wild‐type but not Cc1 –/– mice fed a high‐fat diet for 2 months. Conclusion: Exenatide promotes insulin clearance in parallel with insulin secretion to prevent chronic hyperinsulinemia and the resulting hepatic steatosis, and this contributes to its insulin sensitizing effect. Our data further highlight the relevance of physiologic insulin metabolism in maintaining insulin sensitivity and normal lipid metabolism. (Hepatology Communications 2018;2:35–47)

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+Cc1fl/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+Cc1fl/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.

Background CEACAM1 regulates insulin sensitivity by promoting insulin clearance. Accordingly, global C57BL/6J.Cc1−/− null mice display hyperinsulinemia due to impaired insulin clearance at 2 months of age, followed by insulin resistance, steatohepatitis, visceral obesity and leptin resistance at 6 months. The study aimed at investigating the primary role of hepatic CEACAM1 in insulin and lipid homeostasis independently of its metabolic effect in extra-hepatic tissues. Methods Liver-specific C57BL/6J.AlbCre+Cc1fl/fl mice were generated and their metabolic phenotype was characterized by comparison to that of their littermate controls at 2–9 months of age, using hyperinsulinemic-euglycemic clamp analysis and indirect calorimetry. The effect of hyperphagia on insulin resistance was assessed by pair-feeding experiments. Results Liver-specific AlbCre+Cc1fl/fl mutants exhibited impaired insulin clearance and hyperinsulinemia at 2 months, followed by hepatic insulin resistance (assessed by hyperinsulinemic-euglycemic clamp analysis) and steatohepatitis at ~ 7 months of age, at which point visceral obesity and hyperphagia developed, in parallel to hyperleptinemia and blunted hypothalamic STAT3 phosphorylation in response to an intraperitoneal injection of leptin. Hyperinsulinemia caused hypothalamic insulin resistance, followed by increased fatty acid synthase activity, which together with defective hypothalamic leptin signaling contributed to hyperphagia and reduced physical activity. Pair-feeding experiment showed that hyperphagia caused systemic insulin resistance, including blunted insulin signaling in white adipose tissue and lipolysis, at 8–9 months of age. Conclusion AlbCre+Cc1fl/fl mutants provide an in vivo demonstration of the key role of impaired hepatic insulin clearance and hyperinsulinemia in the pathogenesis of secondary hepatic insulin resistance independently of lipolysis. They also reveal an important role for the liver-hypothalamic axis in the regulation of energy balance and subsequently, systemic insulin sensitivity.

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) promotes hepatic insulin clearance. Consistently, mice with null mutation of Ceacam1 (Cc1(-/-)) exhibit impaired insulin clearance with increased lipid production in liver and redistribution to white adipose tissue, leading to visceral obesity at 2 months of age. When the mutation is propagated on the C57/BL6J genetic background, total fat mass rises significantly with age, and glucose intolerance and systemic insulin resistance develop at 6 months of age. This study was carried out to determine the mechanisms underlying the marked increase in total fat mass in 6-month-old mutants. Indirect calorimetry analysis showed that Cc1(-/-) mice develop hyperphagia and a significant reduction in physical activity, in particular in the early hours of the dark cycle, during which energy expenditure is only slightly lower than in wild-type mice. They also exhibit increased triglyceride accumulation in skeletal muscle, due in part to incomplete fatty acid β-oxidation. Mechanistically, hypothalamic leptin signaling is reduced, as demonstrated by blunted STAT3 phosphorylation in coronal sections in response to an intracerebral ventricular injection of leptin. Hypothalamic fatty-acid synthase activity is also elevated in the mutants. Together, the data show that the increase in total fat mass in Cc1(-/-) mice is mainly attributed to hyperphagia and reduced spontaneous physical activity. Although the contribution of the loss of CEACAM1 from anorexigenic proopiomelanocortin neurons in the arcuate nucleus is unclear, leptin resistance and elevated hypothalamic fatty-acid synthase activity could underlie altered energy balance in these mice.

Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 (CEACAM1) has been implicated in various physiological processes in the vascular systems, including blood vessel formation, and endothelial barrier function. Consistent with a role for hepatic CEACAM1 in promoting insulin sensitivity by mediating insulin clearance and maintaining physiologic plasma insulin levels, we have recently identified a role for hepatic CEACAM1 in preventing cardiac hypertrophy and dysfunction. The aim of this study was to elucidate the contribution of endothelial cell CEACAM1 in cardiac function and fibrosis that has remained elusive. To this end, we generated an endothelial cell-specific Ceacam1 knockout mouse line (VECadCc1−/−). Gomori Trichrome Blue Staining revealed a significant perivascular and interstitial fibrosis in the heart of VECadCc1−/− mice compared to their control littermates. Consistently, the mRNA levels of markers of fibrosis [collagen 1A1, α-SMA and fibroblast-specific protein1 (FSP1)] were elevated with a reciprocal decrease of endothelial cell makers (CD31), indicating endothelial mesenchymal transition (EndMT) in these mice. Cardiac fibrosis was associated with increased activation of the TGF-β1-Smad2/3 signaling pathway. Immunofluorescence staining co-localized CD31 with α-SMA in the myocardial perivascular section of VECadCc1−/− hearts. Moreover, mRNA level of α-SMA, FSP1, SNAIL and SLUG were up-regulated while that of CD31 was down-regulated in mouse heart endothelial cells (MHEC) isolated from VECadCc1−/− mice. The Akt/eNOS pathway was basally inactivated, leading to lower nitric oxide (NO) level in MHEC isolated from VECadCc1−/− mice. Moreover, loss of endothelial CEACAM1 caused reduced association with SHP-2 phosphatase and consequently, reduction in insulin-stimulated IRS-1/Akt/eNOS activation.These studies identified an important role for the loss of CEACAM1 in endothelial cells as a mechanism underlying cardiac fibrosis. Disclosure H.T. Muturi: None. H.E. Ghadieh: None. S.S. Khuder: None. S. Jash: None. R. Abu Helal: None. N.A. Daniels: None. J. Liu: None. V. Puri: None. G. Vazquez: None. R. Gupta: None. S.M. Najjar: None.

The Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 (CEACAM1) promotes insulin sensitivity by inducing insulin clearance and reducing de novo lipogenesis in the liver. Consistently, Cc1−/− mice with null deletion of Ceacam1 gene exhibit hyperinsulinemia and insulin resistance, in addition to steatohepatitis. They also exhibit early pericellular fibrosis. Redelivering Ceacam1 to the liver reverses the altered metabolism and histopathology of Cc1−/− mice. Exenatide, a long-acting glucagon-like peptide-1 receptor agonist, induces Ceacam1 transcription and consequently, reverses impaired insulin clearance and insulin resistance caused by high-fat intake. Additionally, it reverses fat accumulation in the liver. The current studies show that exenatide also restored the activities of alanine transaminase and aspartate aminotransferase, and reversed the inflammatory and oxidative stress response to high-fat diet in wild-type, but not in Cc1−/− mice. Exenatide also prevented diet-induced activation of the TGFβ/Smad2/Smad3 pro-fibrogenic pathways, and normalized the mRNA levels of pro-fibrogenic genes in wild-type, but not in Cc1−/− mice. Together, the data demonstrate that exenatide prevented diet-induced pro-fibrogenesis and hepatocellular injury in a CEACAM1-dependent mechanism.

Impairment of insulin clearance is being increasingly recognized as a critical step in the development of insulin resistance and metabolic disease. The carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) promotes insulin clearance. Null deletion or liver-specific inactivation of Ceacam1 in mice causes a defect in insulin clearance, insulin resistance, steatohepatitis, and visceral obesity. Immunohistological analysis revealed reduction of hepatic CEACAM1 in obese subjects with fatty liver disease. Thus, we aimed to determine whether this occurs at the hepatocyte level in response to systemic extrahepatic factors and whether this holds across species. Northern and Western blot analyses demonstrate that CEACAM1 mRNA and protein levels are reduced in liver tissues of obese individuals compared to their lean age-matched counterparts. Furthermore, Western analysis reveals a comparable reduction of CEACAM1 protein in primary hepatocytes derived from the same obese subjects. Similar to humans, Ceacam1 mRNA level, assessed by quantitative RT-PCR analysis, is significantly reduced in the livers of obese Zucker (fa/fa, ZDF), and Koletsky (f/f) rats relative to their age-matched lean counterparts. These studies demonstrate that the reduction of hepatic CEACAM1 in obesity occurs at the level of hepatocytes and identify the reduction of hepatic CEACAM1 as a common denominator of obesity across multiple species.

The carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) promotes insulin clearance. Mice with global null mutation (Cc1 −/−) or with liver-specific inactivation (L-SACC1) of Cc1 (also known as Ceacam1) gene display hyperinsulinaemia resulting from impaired insulin clearance, insulin resistance, steatohepatitis and obesity. Because increased lipolysis contributes to the metabolic phenotype caused by transgenic inactivation of CEACAM1 in the liver, we aimed to further investigate the primary role of hepatic CEACAM1-dependent insulin clearance in insulin and lipid homeostasis. To this end, we examined whether transgenic reconstitution of CEACAM1 in the liver of global Cc1 −/− mutant mice reverses their abnormal metabolic phenotype. Insulin response was assessed by hyperinsulinaemic–euglycaemic clamp analysis and energy balance was analysed by indirect calorimetry. Mice were overnight-fasted and refed for 7 h to assess fatty acid synthase activity in the liver and the hypothalamus in response to insulin release during refeeding. Liver-based rescuing of CEACAM1 restored insulin clearance, plasma insulin level, insulin sensitivity and steatohepatitis caused by global deletion of Cc1. It also reversed the gain in body weight and total fat mass observed with Cc1 deletion, in parallel to normalising energy balance. Mechanistically, reversal of hyperphagia appeared to result from reducing fatty acid synthase activity and restoring insulin signalling in the hypothalamus. Despite the potential confounding effects of deleting Cc1 from extrahepatic tissues, liver-based rescuing of CEACAM1 resulted in full normalisation of the metabolic phenotype, underscoring the key role that CEACAM1-dependent hepatic insulin clearance pathways play in regulating systemic insulin sensitivity, lipid homeostasis and energy balance.

The pathogenesis of human non-alcoholic fatty liver disease (NAFLD) remains unclear, in particular in the context of its relationship to insulin resistance and visceral obesity. Work on the carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in mice has resolved some of the related questions. CEACAM1 promotes insulin clearance by enhancing the rate of uptake of the insulin-receptor complex. It also mediates a negative acute effect of insulin on fatty acid synthase activity. This positions CEACAM1 to coordinate the regulation of insulin and lipid metabolism. Fed a regular chow diet, global null mutation of Ceacam1 manifest hyperinsulinemia, insulin resistance, obesity, and steatohepatitis. They also develop spontaneous chicken-wire fibrosis, characteristic of non-alcoholic steatohepatitis. Reduction of hepatic CEACAM1 expression plays a significant role in the pathogenesis of diet-induced metabolic abnormalities, as bolstered by the protective effect of hepatic CEACAM1 gain-of-function against the metabolic response to dietary fat. Together, this emphasizes that loss of hepatic CEACAM1 links NAFLD to insulin resistance and obesity.

Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) regulates insulin sensitivity by promoting hepatic insulin clearance and mediating suppression of fatty acid synthase activity. Feeding C57BL/6J male mice with a high-fat (HF) diet for 3–4 weeks triggered a >60% decrease in hepatic CEACAM1 levels to subsequently impair insulin clearance and cause systemic insulin resistance and hepatic steatosis. This study aimed at investigating whether lipolysis drives reduction in hepatic CEACAM1 and whether this constitutes a key mechanism leading to diet-induced metabolic abnormalities. Blocking lipolysis with a daily intraperitoneal injection of nicotinic acid in the last two days of a 30-day HF feeding regimen demonstrated that white adipose tissue (WAT)-derived fatty acids repressed hepatic CEACAM1-dependent regulation of insulin and lipid metabolism in 3-month-old male C57BL/6J mice. Adenoviral-mediated CEACAM1 redelivery countered the adverse metabolic effect of the HF diet on insulin resistance, hepatic steatosis, visceral obesity, and energy expenditure. It also reversed the effect of HF diet on inflammation and fibrosis in WAT and liver. This assigns a causative role for lipolysis-driven decrease in hepatic CEACAM1 level and its regulation of insulin and lipid metabolism in sustaining systemic insulin resistance, hepatic steatosis, and other abnormalities associated with excessive energy supply.

Abdominal obesity is a major risk factor for insulin resistance, type 2 diabetes and cardiovascular diseases. Dietary fat induces insulin resistance in humans and rodents. The current study investigates whether a Chlorogenic acid/Chromium III supplement rescues obesity and insulin resistance caused by high-fat feeding of male C57BL/6 J mice for 7 weeks. Administering an oral daily dose of this supplement in the last 3 weeks of feeding reversed diet-induced body weight gain and insulin resistance, assessed by hyperglycemia, glucose intolerance and insulin intolerance. Indirect calorimetry analysis revealed that this effect is mediated at least partly, by increasing energy expenditure and spontaneous locomoter activity. These findings underscore the important role that chlorogenic acid and chromium play in maintaining glucose metabolism and insulin response in mice fed a high-fat diet.