Monoclonal Antibody chP3R99 Reduces Subendothelial Retention of Atherogenic Lipoproteins in Insulin-Resistant Rats: Acute Treatment Versus Long-Term Protection as an Idiotypic Vaccine for Atherosclerosis.

BACKGROUND: Atherosclerosis is triggered by the retention of apolipoprotein B-containing lipoproteins by proteoglycans. In addition to low-density lipoprotein, remnant lipoproteins have emerged as pivotal contributors to this pathology, particularly in the context of insulin resistance and diabetes. We have previously reported antiatherogenic properties of a monoclonal antibody (chP3R99) that recognizes sulfated glycosaminoglycans on arterial proteoglycans. METHODS AND RESULTS: Solid-phase assays demonstrated that chP3R99 effectively blocked >50% lipoprotein binding to chondroitin sulfate and vascular extracellular matrix in vitro. The preperfusion of chP3R99 (competitive effect) resulted in specific antibody-arterial accumulation and reduced fluorescent lipoprotein retention by ~60% in insulin resistant JCR:LA-cp rats. This competitive reduction was dose dependent (25-250 µg/mL), effectively decreasing deposition of cholesterol associated with lipoproteins. In a 5-week vaccination study in insulin resistant rats with (200 µg subcutaneously, once a week), chP3R99 reduced arterial lipoprotein retention, and was associated with the production of antichondroitin sulfate antibodies (Ab3) able to accumulate in the arteries (dot-blot). Neither the intravenous inoculation of chP3R99 (4.5 mg/kg), nor the immunization with this antibody displayed adverse effects on lipid or glucose metabolism, insulin resistance, liver function, blood cell indices, or inflammation pathways in JCR:LA-cp rats. CONCLUSIONS: Both acute (passive) and long-term administration (idiotypic cascade) of chP3R99 antibody reduced low-density lipoprotein and remnant lipoprotein interaction with proteoglycans in an insulin-resistant setting. These findings support the innovative approach of targeting proatherogenic lipoprotein retention by chP3R99 as a passive therapy or as an idiotypic vaccine for atherosclerosis.

Predictive utility of remnant cholesterol in atherosclerotic cardiovascular disease.

PURPOSE OF REVIEW: Remnant cholesterol (RC) is the cholesterol carried in lipoproteins derived from the catabolism of chylomicrons and very low-density lipoproteins. Evidence supporting the causal relationship of RC with atherosclerotic cardiovascular disease (ASVD) is accumulating rapidly. The number of impactful contributions to this field are increasing and provide a pathophysiological insight into the current residual cardiovascular risk beyond low-density cholesterol (LDL)-cholesterol (LDL-C). They also raise the question of whether RC should be used in prediction models and become the target of new therapeutic interventions. The intent of this review is to highlight the recent advances on the role of RC in atherogenesis and the validation of RC as a predictor of ASVD. RECENT FINDINGS: Numerous prospective and retrospective cohorts helped validate a significant causal relationship of RC with various forms of ASVD, independent of LDL-C. A recent large Mendelian randomization study reinforced the existence of this relationship and showed that the risk of atherosclerotic events was driven nearly entirely by a direct effect of RC. SUMMARY: Both available and accumulating evidence suggest that a lifelong reduction in RC could translate into a substantial reduction in ASVD risk. The data support a revision of current guidelines to incorporate RC as an independent risk factor for ASVD. We propose that early screening of RC should be implemented and that RC lowering should become the target of future drug developments.

Challenges in diagnosis and health care in polycystic ovary syndrome in Canada: a patient view to improve health care.

BACKGROUND: Polycystic Ovary Syndrome (PCOS) is the most common endocrine-metabolic disorder affecting health and quality of life of those affected across the lifespan. We currently have limited evidence-based data on the experience of those living with PCOS in the health care system including diagnosis, health concerns and disease management. The aim of this study was to assess the perceptions of health status, health care experience and disease management support in those affected by PCOS in Alberta, Canada. METHODS: An online questionnaire was completed via REDCap by individuals self-reporting a diagnosis of PCOS. Question categories included demographics, symptoms of PCOS and time to confirm a diagnosis, follow-up care, health concerns, and information resources. Descriptive statistics were used and thematic analyses was applied to open-response questions. RESULTS: Responses from 194 participants living in Canada (93% in Alberta) were included. The average age was 34 ± 8 years and BMI was 35 ± 9. Menstrual irregularity was identified in 84% of respondents as the first symptom noticed and the primary reason for seeking a medical consultation. A PCOS diagnosis occurred on average 4.3 years following awareness of first symptoms and required consultation with more than one primary care provider for 57% of respondents. Half (53%) of respondents reported not receiving a referral to specialists for follow-up care and 70% were not informed about long-term health morbidity such as diabetes or cardiovascular disease. Most respondents (82%) did their own research about PCOS using on-line sources, academic literature and advice from peer support. The participant themes from open questions for improving health care included more resources and support, increased and reliable information, better education and training for clinicians, timely diagnosis, prompt referrals to specialists, and generally more compassion and empathy to the challenges faced by those managing their disease. CONCLUSION: Our findings highlight the health concerns and challenges in health care for those with PCOS. In Alberta, Canada we have identified major gaps in health care including a timely diagnosis, follow up care and supports, and multidisciplinary care. This evidence-based data can be used to inform development of pathways to improve the health care experience in those affected by PCOS.

ApoB-lipoprotein remnant dyslipidemia and high-fat meal intolerance is associated with markers of cardiometabolic risk in youth with obesity.

INTRODUCTION: Cardiovascular disease (CVD) originates in childhood and risk is exacerbated in obesity. Mechanisms of the etiologic link between early adiposity and CVD-risk remain unclear. Postprandial or non-fasting dyslipidemia is characterized by elevated plasma triglycerides (TG) and intestinal-apolipoprotein(apo)B48-remnants following a high-fat meal and is a known CVD-risk factor in adults. The aim of this study was to determine (a) whether the fasting concentration of apoB48-remnants can predict impaired non-fasting apoB48-lipoprotein metabolism (fat intolerance) and (b) the relationship of these biomarkers with cardiometabolic risk factors in youth with or without obesity. METHODS: We assessed fasting and non-fasting lipids in youth without obesity (n = 22, 10 males, 12 females) and youth with obesity (n = 13, 5 males, 8 females) with a mean BMI Z-score of 0.19 ± 0.70 and 2.25 ± 0.31 (P = .04), respectively. RESULTS: Fasting and non-fasting apoB48-remnants were elevated in youth with obesity compared to youth without obesity (apoB48: 18.04 ± 1.96 vs 8.09 ± 0.59, P < .0001, and apoB48AUC : 173.0 ± 20.86 vs 61.99 ± 3.44, P < .001). Furthermore, fasting plasma apoB48-remnants were positively correlated with the non-fasting response in apoB48AUC (r = 0.84, P < .0001) as well as other cardiometabolic risk factors including HOMA-IR (r = 0.61, P < .001) and leptin (r = 0.56, P < .0001). CONCLUSION: Fasting apoB48-remnants are elevated in youth with obesity and predict apoB48 postprandial dyslipidemia. ApoB48-remnants are associated with the extent of fat intolerance and appear to be potential biomarker of CVD-risk in youth.

ApoB48-Lipoproteins Are Associated with Cardiometabolic Risk in Adolescents with and without Polycystic Ovary Syndrome.

CONTEXT: Adolescents with polycystic ovary syndrome (PCOS) have increased incidence of cardiometabolic risk factors including dyslipidemia. Atherogenic apolipoprotein (apo) B-lipoprotein remnants are associated with increased cardiovascular disease (CVD) risk. OBJECTIVE: The aim of this study was to determine the concentrations of fasting plasma apoB-lipoprotein remnants, apoB48 and apoB100, and their association with cardiometabolic risk factors and androgen indices in adolescent girls with and without PCOS. DESIGN SETTING AND PARTICIPANTS: Participants (n = 184) aged 17 years were recruited in the Menstruation in Teenagers Study from the Western Australian Pregnancy Cohort (Raine) Study. THE MAIN OUTCOME MEASURES: Fasting plasma apo-B48 and -B100 lipoprotein remnant concentrations in adolescent girls with and without PCOS. RESULTS: Fasting plasma apoB48-lipoprotein remnants but not apoB100-lipoprotein remnants were elevated in adolescent girls with increased cardiometabolic risk compared with those with lower cardiometabolic risk (13.91 ± 5.06 vs 12.09 ± 4.47 µg/mL, P < .01). ApoB48-lipoprotein remnants were positively correlated with fasting plasma triglycerides (b = .43, P < .0001). The prevalence of increased cardiometabolic risk factors was 2-fold higher in those diagnosed with PCOS (35.3%) than in those without PCOS (16.3%).Conclusion: Adolescents with PCOS have a 2-fold higher incidence of cardiometabolic risk factors than those without PCOS. Fasting apoB48-lipoprotein remnants are elevated in adolescent girls with a high prevalence of cardiometabolic risk factors.

ApoB48-remnant lipoproteins are associated with increased cardiometabolic risk in adolescents.

BACKGROUND AND AIMS: Cardiovascular disease (CVD) begins in youth, and is exacerbated by obesity and metabolic syndrome. Apolipoprotein (Apo)B-remnant cholesterol is considered a primary contributor to CVD risk. Fasting plasma apoB48 can be used as a biomarker of intestinal remnant cholesterol as well as postprandial dyslipidemia. In adults, elevated fasting plasma apoB48 strongly associates with cardiometabolic risk factors and obesity, whereas in adolescents there is limited data. The aim of this study was to measure fasting plasma apoB48 and determine the relationship with cardiometabolic risk factors in adolescents. METHODS: This is a cross-sectional study of fasting plasma apoB48 from the Western Australian Pregnancy Cohort (Raine) Study. Subjects were adolescent males and females aged 17 years with complete fasting plasma apoB48, biochemical, and anthropometry data (n = 1045). The relationship between fasting plasma apoB48 and other cardiometabolic risk factors was determined. The high-risk metabolic cluster variable was defined using elevated BMI, HOMA-IR, fasting plasma triglycerides, and systolic blood pressure. RESULTS: Fasting plasma apoB48 was significantly higher in male (15.28 ± 2.95 µg/mL) compared to female (12.45 ± 2.43 µg/mL) adolescents (p = 0.0003), and was increased by 21% (3.60 µg/mL; p = 0.0000) in the high-risk metabolic cluster group and more pronounced in males (31%, 6.15 µg/mL; p = 0.0000). Fasting plasma apoB48 was positively associated with fasting plasma triglycerides, total-cholesterol (but not LDL-C), insulin, leptin, HOMA-IR, and the anthropometric parameters, waist-circumference and skinfold-thickness. Fasting plasma apoB48 was inversely associated with fasting plasma HDL-C, and adiponectin. CONCLUSIONS: Plasma apoB48 remnant lipoproteins associate with cardiometabolic risk factors in adolescents and provide support for the screening of remnant cholesterol in youth.

Intestinal lymphatic HDL miR-223 and ApoA-I are reduced during insulin resistance and restored with niacin.

The intestine is involved in whole-body lipid and cholesterol homeostasis and secretes lipoproteins containing apolipoprotein (Apo)B48 and discrete ApoA-I into the mesenteric lymph. The lymphatic system has been proposed to have a significant role in the reverse cholesterol transport pathway associated with HDL-ApoA-I. In conditions of insulin resistance (IR), there is intestinal overproduction of chylomicrons containing ApoB48; however, there is limited data on the intestinal synthesis and secretion of HDL-ApoA-I. microRNA (miR)-223 has been shown to regulate peripheral HDL metabolism and may impact intestinal-derived HDL. Niacin (nicotinic acid; vitamin B3) is known to regulate lipid metabolism, but the role of niacin in modulating intestinal lipid and lipoprotein (ApoB48 and ApoA-I) metabolism is unknown. The aim of this study was to determine the secretion of intestinal lymphatic HDL-ApoA-I and the effect of dietary intervention with niacin on these pathways in a rodent model of IR. HDL was isolated from intestinal mesenteric lymph by density ultracentrifugation, and subsequent HDL miR analysis was developed in collaboration with Exiqon Services. Insulin-resistant rodents were fed chow or chow with niacin (1% w/w) for 6 wk. Intestinal lymph HDL-ApoA-I and miR-223 expression were lower by at least 45 and 60%, respectively, and lymph HDL was associated with 85% higher triglyceride (TG) content in IR compared to non-IR control group. Niacin was found to increase secretion of lymph HDL and miR-223 by at least 50-60% and to deplete the TGs associated with HDL compared with the nontreated IR group. Niacin significantly increased peroxisome proliferator-activating nuclear receptor α and carnitine palmitoyltransferase I α mRNA and annulled Tnf-α mRNA expression in intestinal (jejunal) explants. Altered intestinal lymphatic HDL-ApoA-I and miR-223 metabolism in IR and modulation by niacin may provide insight into the intestinal-mediated regulation of the reverse cholesterol transport pathway.-Mangat, R., Borthwick, F., Haase, T., Jacome, M., Nelson, R., Kontush, A., Vine, D. F., Proctor, S. D. Intestinal lymphatic HDL miR-223 and ApoA-I are reduced during insulin resistance and restored with niacin.

Surgical Anatomy Does Not Affect the Progression of Intestinal Failure-Associated Liver Disease in Neonatal Piglets.

BACKGROUND: Intestinal failure-associated liver disease (IFALD) causes significant morbidity in neonates with short bowel syndrome (SBS) dependent on parenteral nutrition (PN). Resected ileum, with loss of the ileocecal valve (ICV), is the most common anatomy in SBS, yet its impact on IFALD has not been adequately studied. METHODS: Neonatal piglets were randomized to 75% intestinal resection with jejunocolic anastomosis (JC, n = 12), 75% resection with jejunoileal anastomosis and intact ICV (JI, n = 13), PN-fed sham (sham, n = 14), or sow-fed control (SF, n = 8). Surgical and sham piglets received 100% PN for 14 days before bile flow was measured and blood chemistry, liver pathology, jejunal permeability, and bacterial translocation were assessed. RESULTS: Bile flow was lower for PN-fed compared with SF (P = .002) but not different between the PN-fed groups. Total bilirubin (P = .03) and liver pathology (P < .001) were greater in PN-fed than SF groups but not different between PN-fed groups. Serum bile acids were increased in sham (P = .01) but not different between SBS groups. PN-fed piglets with sepsis had lower bile flow (P = .001) and increased bilirubin (P = .04). Neither jejunal permeability nor bacterial translocation were different between JC, JI, or sham groups. CONCLUSION: Contrary to our hypothesis, the remnant anatomy does not appear to worsen the progression of IFALD. However, the role of sepsis in IFALD should be further explored, in addition to other mechanisms, including PN factors, host immune responses, and intestinal bacterial dysbiosis.

The Effect of PCSK9 Loss-of-Function Variants on the Postprandial Lipid and ApoB-Lipoprotein Response.

Context: Proprotein convertase subtilisin kexin 9 (PCSK9) mediates degradation of the low-density lipoprotein receptor (LDLR), thereby increasing plasma low-density lipoprotein cholesterol (LDL-C). Variations in the PCSK9 gene associated with loss of function (LOF) of PCSK9 result in greater expression of hepatic LDLR, lower concentrations of LDL-C, and protection from cardiovascular disease (CVD). Apolipoprotein-B (apoB) remnants also contribute to CVD risk and are similarly cleared by the LDLR. We hypothesized that PCSK9-LOF carriers would have lower fasting and postprandial remnant lipoproteins on top of lower LDL-C. Objective: To compare fasting and postprandial concentrations of triglycerides (TGs), total apoB, and apoB48 as indicators of remnant lipoprotein metabolism in PCSK9-LOF carriers with those with no PCSK9 variants. Design: Case-control, metabolic study. Setting: Clinical Research Center of The Ottawa Hospital. Participants: Persons with one or more copies of the L10ins/A53V and/or I474V and/or R46L PCSK9 variant and persons with no PCSK9 variants. Intervention: Oral fat tolerance test. Main Outcomes Measures: Fasting and postprandial plasma TG, apoB48, total apoB, total cholesterol, and PCSK9 were measured at 0, 2, 4, and 6 hours after an oral fat load. Results: Participants with PCSK9-LOF variants (n = 22) had reduced fasting LDL-C (-14%) as well as lower fasting TG (-21%) compared with noncarrier controls (n = 23). LOF variants also had reduced postprandial total apoB (-17%), apoB48 (-23%), and TG (-18%). Postprandial PCSK9 declined in both groups (-24% vs -16%, respectively). Conclusions: Participants carrying PCSK9-LOF variants had attenuated levels of fasting and postprandial TG, apoB48, and total apoB. This may confer protection from CVD and further validate the use of PCSK9 inhibitors to lower CVD risk.

Nutritional and Lipid Modulation of PCSK9: Effects on Cardiometabolic Risk Factors.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease involved in the regulation of LDL receptor (LDLR) expression and apolipoprotein B lipoprotein cholesterol metabolism. Hepatic PCSK9 protein expression, activity, and secretion have been shown to affect cholesterol homeostasis. An upregulation of hepatic PSCK9 protein leads to increased LDLR degradation, resulting in decreased uptake of apoB lipoproteins and a consequent increase in the plasma concentration of these lipoproteins, including LDL and chylomicron remnants. Hence, PCSK9 has become a novel target for lipid-lowering therapies. The aim of this review is to outline current findings on the metabolic and dietary regulation of PCSK9 and effects on cholesterol, apoB lipoprotein metabolism, and cardiovascular disease (CVD) risk. PCSK9 gene and protein expression have been shown to be regulated by metabolic status and the diurnal pattern. In the fasting state, plasma PCSK9 is reduced via modulation of the nuclear transcriptional factors, including sterol regulatory element-binding protein (SREBP) 1c, SREBP2, and hepatocyte nuclear factor 1α. Plasma PCSK9 concentrations are also known to be positively associated with plasma insulin and homeostasis model assessment of insulin resistance, and appear to be regulated by SREBP1c independently of glucose status. Plasma PCSK9 concentrations are stable in response to high-fat or high-protein diets in healthy individuals; however, this response may differ in altered metabolic conditions. Dietary n-3 polyunsaturated fatty acids have been shown to reduce plasma PCSK9 concentration and hepatic PCSK9 mRNA expression, consistent with their lipid-lowering effects, whereas dietary fructose appears to upregulate PCSK9 mRNA expression and plasma PCSK9 concentrations. Further studies are needed to elucidate the mechanisms of how dietary components regulate PCSK9 and effects on cholesterol and apoB lipoprotein metabolism, as well as to delineate the clinical impact of diet on PCSK9 in terms of CVD risk.

Synergy of glucagon-like peptide-2 and epidermal growth factor coadministration on intestinal adaptation in neonatal piglets with short bowel syndrome.

Glucagon-like peptide-2 (GLP-2) and epidermal growth factor (EGF) treatment enhance intestinal adaptation. To determine whether these growth factors exert synergistic effects on intestinal growth and function, GLP-2 and EGF-containing media (EGF-cm) were administered, alone and in combination, in neonatal piglet models of short bowel syndrome (SBS). Neonatal Landrace-Large White piglets were block randomized to 75% midintestinal [jejunoileal (JI) group] or distal intestinal [jejunocolic (JC) group] resection or sham control, with 7-day infusion of saline (control), intravenous human GLP-2 (11 nmol·kg-1·day-1) alone, enteral EGF-cm (80 µg·kg-1·day-1) alone, or GLP-2 and EGF-cm in combination. Adaptation was assessed by intestinal length, histopathology, Üssing chamber analysis, and real-time quantitative PCR of intestinal growth factors. Combined EGF-cm and GLP-2 treatment increased intestinal length in all three surgical models (P < 0.01). EGF-cm alone selectively increased bowel weight per length and jejunal villus height in the JI group only. The JC group demonstrated increased intestinal weight and villus height (P < 0.01) when given either GLP-2 alone or in combination with EGF-cm, with no effect of EGF-cm alone. Jejunal permeability of mannitol and polyethylene glycol decreased with combination therapy in both SBS groups (P < 0.05). No difference was observed in fat absorption or body weight gain. IGF-1 mRNA was differentially expressed in JI vs. JC piglets with treatment. Combined treatment with GLP-2 and EGF-cm induced intestinal lengthening and decreased permeability, in addition to the trophic effects of GLP-2 alone. Our findings demonstrate the benefits of novel combination GLP-2 and EGF treatment for neonatal SBS, especially in the JC model representing most human infants with SBS.NEW & NOTEWORTHY Glucagon-like peptide-2 (GLP-2) and epidermal growth factor (EGF) are intestinotrophic, with demonstrated benefit in both animal models and human studies of short bowel syndrome (SBS). The current research shows that over and above known trophic effects, the combination of GLP-2 and EGF synergistically lengthens the bowel in neonatal piglet models of SBS. Most notable benefit occurred with resection of the terminal ileum, the common clinical anatomy seen in neonatal SBS and associated with least de novo lengthening postsurgery.

Differential Effects on Intestinal Adaptation Following Exogenous Glucagon-Like Peptide 2 Therapy With and Without Enteral Nutrition in Neonatal Short Bowel Syndrome [Formula: see text].

BACKGROUND: We aim to study the efficacy of exogenously administered glucagon-like peptide 2 (GLP-2) on intestinal adaptation in 2 preclinical models of neonatal short bowel syndrome (SBS) according to remnant intestinal anatomy, with and without ileum. Furthermore, we aim to determine if this adaptive effect was potentiated with enteral nutrition (EN). METHODS: Neonatal piglets were block-randomized to 75% mid-intestinal (JI group, retains ileum) or distal-intestinal (JC group, has no ileum) resection or no resection (sham control) and GLP-2 treatment (11 nmol/kg/d) or saline control for 7 days. Piglets received nutrition support, either 100% parenteral nutrition (PN; 0% EN, n = 32 in total) or 80% PN + 40% EN (n = 28 in total). Adaptation was assessed by morphological and histological changes, as well as RT quantitative polymerase chain reaction of nutrient transporters and tight junctional proteins and fat absorption. Data are analyzed by 3-way analysis of variance (ANOVA) and 2-way ANOVA per EN level. RESULTS: GLP-2 treatment lengthened villi, deepened crypts, and improved intestinal weight in the remnant intestine of JC piglets. EN was a more potent adaptive stimulus for JI piglets. Small intestinal lengthening occurred only in the JI group, when given EN. There was no difference in total fat absorption and messenger RNA expression of nutrient transporters and tight junctional proteins. CONCLUSIONS: GLP-2 administration augmented structural adaptation in JC piglets with distal intestinal resection. Given JI anatomy, further stimulation by GLP-2 treatment over innate adaptation and stimulation by EN was modest and restricted to ileum. The differential effect of GLP-2 in neonatal SBS, depending on remnant anatomy, has important implications for clinical translation and planning of clinical trials.

Impaired ApoB-Lipoprotein and Triglyceride Metabolism in Obese Adolescents With Polycystic Ovary Syndrome.

CONTEXT: Adolescents with polycystic ovary syndrome (PCOS) have atherogenic dyslipidemia and increased cardiovascular disease (CVD) risk, and this is exacerbated in obesity. OBJECTIVE: To determine and compare fasting and nonfasting lipid and apolipoprotein (Apo)B-lipoprotein metabolism in 3 groups of adolescent girls: healthy-weight controls, obese without PCOS (obese-control), and obese with PCOS (obese-PCOS). DESIGN, SETTING, AND PARTICIPANTS: Participants aged 12 to 17 years were recruited for this cross-sectional study from a pediatric weight management clinic and the local community in Alberta, Canada. MAIN OUTCOME MEASURES: Plasma lipids and ApoB lipoproteins, including triglycerides (TGs) and ApoB100- and ApoB48-lipoproteins, were measured in the fasted and postprandial state following a high-fat meal. RESULTS: Obese-control (n = 12) and obese-PCOS (n = 18) groups had twofold higher concentrations of fasting plasma TG and ApoB100- and ApoB48-lipoprotein remnants compared to healthy-weight controls (n = 10) (ApoB48-lipoproteins: 19.32 ± 2.10, 24.02 ± 4.28, and 8.95 ± 1.05 µg/mL, respectively; P < 0.001). The obese-PCOS group had 50% higher fasting plasma TG level compared to the obese-control group. The postprandial response was higher in both obese-controls and obese-PCOS subjects compared with healthy-weight controls in plasma TG area under the curve (AUC) (1028.0 ± 83.67, 1587.01 ± 259.6, and 615.42 ± 76.42 µg/mL⋅h, respectively; P < 0.01) and ApoB48(AUC) (191.30 ± 19.06, 238.8 ± 37.73, and 96.58 ± 9.17 µg/mL⋅h, respectively; P < 0.0001). Nonfasting plasma TG(AUC) and ApoB48(AUC) were positively correlated with free testosterone (r = 0.38; P < 0.001 and r = 0.33; P < 0.05, respectively), and these relationships were highly associated with insulin and body mass index. CONCLUSIONS: Adolescent girls with obesity and PCOS have elevated fasting and postprandial plasma TG and ApoB-lipoprotein remnants, providing evidence of early subclinical CVD risk, and these indices are highly associated with impaired insulin metabolism and hyperandrogenemia.

Mechanisms of Comorbidities Associated With the Metabolic Syndrome: Insights from the JCR:LA-cp Corpulent Rat Strain.

Obesity and its metabolic complications have emerged as the epidemic of the new millennia. The use of obese rodent models continues to be a productive component of efforts to understand the concomitant metabolic complications of this disease. In 1978, the JCR:LA-cp rat model was developed with an autosomal recessive corpulent (cp) trait resulting from a premature stop codon in the extracellular domain of the leptin receptor. Rats that are heterozygous for the cp trait are lean-prone, while those that are homozygous (cp/cp) spontaneously display the pathophysiology of obesity as well as a metabolic syndrome (MetS)-like phenotype. Over the years, there have been formidable scientific contributions that have originated from this rat model, much of which has been reviewed extensively up to 2008. The premise of these earlier studies focused on characterizing the pathophysiology of MetS-like phenotype that was spontaneously apparent in this model. The purpose of this review is to highlight areas of recent advancement made possible by this model including; emerging appreciation of the "thrifty gene" hypothesis in the context of obesity, the concept of how chronic inflammation may drive obesogenesis, the impact of acute forms of inflammation to the brain and periphery during chronic obesity, the role of dysfunctional insulin metabolism on lipid metabolism and vascular damage, and the mechanistic basis for altered vascular function as well as novel parallels between the human condition and the female JCR:LA-cp rat as a model for polycystic ovary disease (PCOS).

Hypolipidemic and cardioprotective benefits of a novel fireberry hawthorn fruit extract in the JCR:LA-cp rodent model of dyslipidemia and cardiac dysfunction.

Hawthorn is a widely used herbal alternative medicine for the treatment of various cardiovascular diseases. However, the attributed health benefits, purported to be due to the presence of phenolic compounds, may depend on both the specific species and plant part. Studies to date investigating effects of hawthorn on heart disease(s) have used well-described European and/or Asian species, while little is known regarding the bioactivity of species native to North America. Six weeks of supplementation of both fireberry hawthorn berry (native Crataegus chrysocarpa) and English hawthorn leaf (C. monogyna, naturalized in North America) in the JCR:LA-cp rat, resulted in a significant reduction in heart weight, fasting LDL-C and improved heart function (p < 0.05). Fasting triglyceride and myocardial fibrosis were also reduced, but only by the berry extract. We demonstrate that both of the Canadian-sourced hawthorn extracts (introduced leaf and native berry) have cardioprotective benefits, likely via increased availability of nitric oxide.

Beef Fat Enriched with Polyunsaturated Fatty Acid Biohydrogenation Products Improves Insulin Sensitivity Without Altering Dyslipidemia in Insulin Resistant JCR:LA-cp Rats.

The main dietary sources of trans fatty acids are partially hydrogenated vegetable oils (PHVO), and products derived from polyunsaturated fatty acid biohydrogenation (PUFA-BHP) in ruminants. Trans fatty acid intake has historically been associated with negative effects on health, generating an anti-trans fat campaign to reduce their consumption. The profiles and effects on health of PHVO and PUFA-BHP can, however, be quite different. Dairy products naturally enriched with vaccenic and rumenic acids have many purported health benefits, but the putative benefits of beef fat naturally enriched with PUFA-BHP have not been investigated. The objective of the present experiment was to determine the effects of beef peri-renal fat (PRF) with differing enrichments of PUFA-BHP on lipid and insulin metabolism in a rodent model of dyslipidemia and insulin resistance (JCR:LA-cp rat). The results showed that 6 weeks of diet supplementation with beef PRF naturally enriched due to flaxseed (FS-PRF) or sunflower-seed (SS-PRF) feeding to cattle significantly improved plasma fasting insulin levels and insulin sensitivity, postprandial insulin levels (only in the FS-PRF) without altering dyslipidemia. Moreover, FS-PRF but not SS-PRF attenuated adipose tissue accumulation. Therefore, enhancing levels of PUFA-BHP in beef PRF with FS feeding may be a useful approach to maximize the health-conferring value of beef-derived fats.

Vaccenic acid suppresses intestinal inflammation by increasing anandamide and related N-acylethanolamines in the JCR:LA-cp rat.

Vaccenic acid (VA), the predominant ruminant-derivedtransfat in the food chain, ameliorates hyperlipidemia, yet mechanisms remain elusive. We investigated whether VA could influence tissue endocannabinoids (ECs) by altering the availability of their biosynthetic precursor, arachidonic acid (AA), in membrane phospholipids (PLs). JCR:LA-cprats were assigned to a control diet with or without VA (1% w/w),cis-9,trans-11 conjugated linoleic acid (CLA) (1% w/w) or VA+CLA (1% + 0.5% w/w) for 8 weeks. VA reduced the EC, 2-arachidonoylglycerol (2-AG), in the liver and visceral adipose tissue (VAT) relative to control diet (P< 0.001), but did not change AA in tissue PLs. There was no additive effect of combining VA+CLA on 2-AG relative to VA alone (P> 0.05). Interestingly, VA increased jejunal concentrations of anandamide and those of the noncannabinoid signaling molecules, oleoylethanolamide and palmitoylethanolamide, relative to control diet (P< 0.05). This was consistent with a lower jejunal protein abundance (but not activity) of their degrading enzyme, fatty acid amide hydrolase, as well as the mRNA expression of TNFα and interleukin 1ß (P< 0.05). The ability of VA to reduce 2-AG in the liver and VAT provides a potential mechanistic explanation to alleviate ectopic lipid accumulation. The opposing regulation of ECs and other noncannabinoid lipid signaling molecules by VA suggests an activation of benefit via the EC system in the intestine.

Cardiometabolic and reproductive benefits of early dietary energy restriction and voluntary exercise in an obese PCOS-prone rodent model.

Polycystic ovary syndrome (PCOS) is one of the most common endocrine-metabolic disorders in women of reproductive age characterized by ovulatory dysfunction, hyperandrogenism and cardiometabolic risk. The overweight-obese PCOS phenotype appears to have exacerbated reproductive dysfunction and cardiometabolic risk. In overweight-obese adult women with PCOS, exercise and energy restricted diets have shown limited and inconsistent effects on both cardiometabolic indices and reproductive outcomes. We hypothesized that an early lifestyle intervention involving exercise and dietary energy restriction to prevent or reduce the propensity for adiposity would modulate reproductive indices and cardiometabolic risk in an obese PCOS-prone rodent model. Weanling obese PCOS-prone and Lean-Control JCR:LA-cp rodents were given a chow diet ad libitum or an energy-restricted diet combined with or without voluntary exercise (4  h/day) for 8 weeks. Dietary energy restriction and exercise lowered total body weight gain and body fat mass by 30% compared to free-fed sedentary or exercising obese PCOS-prone animals (P<0.01). Energy restriction induced an increase in exercise intensity compared to free-feeding plus exercise conditions. Energy restriction and exercise decreased fasting plasma triglycerides and apoB48 concentrations in obese PCOS-prone animals compared to free-fed and exercise or sedentary groups. The energy restriction and exercise combination in obese PCOS-prone animals significantly increased plasma sex-hormone binding globulin, hypothalamic cocaine-and amphetamine-regulated transcript (CART) and Kisspeptin mRNA expression to levels of the Lean-Control group, and this was further associated with improvements in estrous cyclicity. The combination of exercise and dietary energy restriction when initiated in early life exerts beneficial effects on cardiometabolic and reproductive indices in an obese PCOS-prone rodent model, and this may be associated with normalization of the hypothalamic neuropeptides, Kisspeptin and CART.

Choline deficiency impairs intestinal lipid metabolism in the lactating rat.

Choline is a precursor to phosphatidylcholine (PC), a structural molecule in cellular membranes that is crucial for cell growth and function. PC is also required for the secretion of lipoprotein particles from liver and intestine. Choline requirements are increased during lactation when maternal choline is supplied to the offspring through breast milk. To investigate the effect of dietary choline on intestinal lipid metabolism during lactation, choline-supplemented (CS), phosphatidylcholine-supplemented (PCS) or choline-deficient (CD) diets were fed to dams during the suckling period. CD dams had lower plasma triacylglycerol, cholesterol and apoB in the fasted state and following a fat-challenge (P < .05). There was a higher content of neutral lipids and lower content of PC in the intestine of CD dams, compared with CS and PCS fed animals (P < .05). In addition, there was lower (P < .05) villus height in CD dams, which indicated a reduced absorptive surface area in the intestine. Choline is critical for the absorption of fat in lactating rats and choline deficiency alters intestinal morphology and impairs chylomicron secretion by limiting the supply of PC.

Interrelationship of CB1R and OBR pathways in regulation of metabolic, neuroendocrine, and behavioral responses to food restriction and voluntary wheel running.

We hypothesized the cannabinoid-1 receptor and leptin receptor (ObR) operate synergistically to modulate metabolic, neuroendocrine, and behavioral responses of animals exposed to a survival challenge (food restriction and wheel running). Obese-prone (OP) JCR:LA-cp rats, lacking functional ObR, and lean-prone (LP) JCR:LA-cp rats (intact ObR) were assigned to OP-C and LP-C (control) or CBR1-antagonized (SR141716, 10 mg/kg body wt in food) OP-A and LP-A groups. After 32 days, all rats were exposed to 1.5-h daily meals without the drug and 22.5-h voluntary wheel running, a survival challenge that normally culminates in activity-based anorexia (ABA). Rats were removed from the ABA protocol when body weight reached 75% of entry weight (starvation criterion) or after 14 days (survival criterion). LP-A rats starved faster (6.44 ± 0.24 days) than LP-C animals (8.00 ± 0.29 days); all OP rats survived the ABA challenge. LP-A rats lost weight faster than animals in all other groups (P < 0.001). Consistent with the starvation results, LP-A rats increased the rate of wheel running more rapidly than LP-C rats (P = 0.001), with no difference in hypothalamic and primary neural reward serotonin levels. In contrast, OP-A rats showed suppression of wheel running compared with the OP-C group (days 6-14 of ABA challenge, P < 0.001) and decreased hypothalamic and neural reward serotonin levels (P < 0.01). Thus there is an interrelationship between cannabinoid-1 receptor and ObR pathways in regulation of energy balance and physical activity. Effective clinical measures to prevent and treat a variety of disorders will require understanding of the mechanisms underlying these effects.