Association between increased plasma ceramides and chronic kidney disease in patients with and without ischemic heart disease.

AIM: Plasma levels of certain ceramides are increased in patients with ischemic heart disease (IHD). Many risk factors for IHD are also risk factors for chronic kidney disease (CKD), but it is currently uncertain whether plasma ceramide levels are increased in patients with CKD. METHODS: We measured six previously identified high-risk plasma ceramide concentrations [Cer(d18:1/16:0), Cer(d18:1/18:0), Cer(d18:1/20:0), Cer(d18:1/22:0), Cer(d18:1/24:0) and Cer(d18:1/24:1)] in 415 middle-aged individuals who attended our clinical Cardiology and Diabetes services over a period of 9 months. RESULTS: A total of 97 patients had CKD (defined as e-GFRCKD-EPI<60ml/min/1.73m2 and/or urinary albumin-to-creatinine ratio≥30mg/g), 117 had established IHD and 242 had type 2 diabetes. Patients with CKD had significantly (P=0.005 or less) higher levels of plasma Cer(d18:1/16:0), Cer(d18:1/18:0), Cer(d18:1/20:0), Cer(d18:1/22:0), Cer(d18:1/24:0), and Cer(d18:1/24:1) compared to those without CKD. The presence of CKD remained significantly associated with higher levels of plasma ceramides (standardized beta coefficients ranging from 0.124 to 0.227, P<0.001) even after adjustment for body mass index, smoking, hypertension, diabetes, prior IHD, plasma LDL-cholesterol, hs-C-reactive protein levels and use of any lipid-lowering medications. Notably, more advanced stages of CKD and abnormal albuminuria were both associated (independently of each other) with increased levels of plasma ceramides. These results were consistent in all subgroups considered, including patients with and without established IHD or those with and without diabetes. CONCLUSION: Increased levels of plasma ceramides are associated with CKD independently of pre-existing IHD, diabetes and other established cardiovascular risk factors.

PNPLA3 polymorphism influences the association between high-normal TSH level and NASH in euthyroid adults with biopsy-proven NAFLD.

AIM: We aimed to evaluate the association between serum thyroid stimulating hormone (TSH) levels, within the reference range, and the histological severity of nonalcoholic fatty liver disease (NAFLD), and whether this association was modulated by the patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 polymorphism. MATERIALS AND METHODS: We enrolled 327 euthyroid individuals with biopsy-proven NAFLD, who were subdivided into two groups, i.e., a 'strict-normal' TSH group (TSH level 0.4 to 2.5mIU/L; n=283) and a 'high-normal' TSH group (TSH level 2.5 to 5.3mIU/L with normal thyroid hormones; n=44). Logistic regression analyses were performed to assess the association between TSH status and presence of nonalcoholic steatohepatitis (NASH) after stratifying subjects by PNPLA3 genotypes. RESULTS: Compared to strict-normal TSH group, patients with high-normal TSH levels were younger and had a greater prevalence of NASH and higher histologic NAFLD activity score. After stratifying by PNPLA3 genotypes, the significant association between high-normal TSH levels and presence of NASH was restricted only to carriers of the PNPLA3 G risk allele and remained significant even after adjustment for potential confounding factors (adjusted-odds ratio: 3.279; 95% CI: 1.298-8.284; P=0.012). CONCLUSION: In euthyroid individuals with biopsy-proven NAFLD, we found a significant association between high-normal TSH levels and NASH. After stratifying by PNPLA3 rs738409 genotypes, this association was observed only among carriers of the PNPLA3 G risk allele.

Associations between specific plasma ceramides and severity of coronary-artery stenosis assessed by coronary angiography.

AIM: Recent prospective studies have identified distinct plasma ceramides as strong predictors of major adverse cardiovascular events in patients with established or suspected coronary artery disease (CAD). Currently, it is uncertain whether higher levels of distinct plasma ceramides are associated with greater angiographic severity of coronary-artery stenoses in this patient population. METHODS: We measured six previously identified high-risk plasma ceramide species [Cer(d18:1/16:0), Cer(d18:1/18:0), Cer(d18:1/20:0), Cer(d18:1/22:0), Cer(d18:1/24:0) and Cer(d18:1/24:1)] in 167 consecutive patients with established or suspected CAD, who underwent urgent or elective coronary angiography. RESULTS: Approximately 77% of patients had a significant stenosis (≥50%) in one or more of the main coronary arteries, the majority of whom (∼60%) had a significant stenosis in the left anterior descending (LAD) artery. Of the six measured plasma ceramides, higher levels of plasma Cer(d18:1/20:0) (adjusted-odds ratio 1.39, 95%CI 1.0-1.99), Cer(d18:1/22:0) (adjusted-odds ratio 1.57, 95%CI 1.08-2.29) and Cer(d18:1/24:0) (adjusted-odds ratio 1.59, 95%CI 1.08-2.32) were significantly associated with the presence of LAD stenosis≥50%, after adjustment for age, sex, smoking, pre-existing CAD, hypertension, diabetes, dyslipidaemia, lipid-lowering therapy, estimated glomerular filtration rate and plasma C-reactive protein levels. Almost identical results were found even after excluding patients (n=15) with acute ST-elevation myocardial infarction. Similar results were also found when patients were categorized according to the Gensini severity score. CONCLUSION: Our cross-sectional study shows for the first time that higher levels of specific plasma ceramides are independently associated with a greater severity of coronary-artery stenoses in the LAD artery in patients who had suspected or established CAD.

Higher liver stiffness scores are associated with early kidney dysfunction in patients with histologically proven non-cirrhotic NAFLD.

AIM: The association between Liver fibrosis (LF), as assessed by either histology or Liver stiffness measurement (LSM), and the presence of Early kidney dysfunction (EKD) was investigated in this study, as was also the diagnostic performance of LSM for identifying the presence of EKD in patients with Non-alcoholic fatty liver disease (NAFLD). MATERIALS AND METHODS: A total of 214 adults with non-cirrhotic biopsy-proven NAFLD were recruited from two independent medical centres. Their histological stage of LF was quantified using Brunt's criteria. Vibration-controlled Transient elastography (TE), using M-probe (FibroScan®) ultrasound, was performed in 154 patients and defined as significant when LSM was≥8.0kPa. EKD was defined as the presence of microalbuminuria with an estimated glomerular filtration rate≥60mL/min/1.73 m2. Logistic regression modelling was used to estimate the likelihood of having EKD with NAFLD (LSM-EKD model). RESULTS: The prevalence of EKD was higher in patients with vs without LF on histology (22.14% vs 4.82%, respectively; P<0.001) and, similarly, EKD prevalence was higher in patients with LSM≥8.0kPa vs LSM<8.0kPa (23.81% vs 6.59%, respectively; P<0.05). The area under the ROC curve of the LSM-EKD model for identifying EKD was 0.80 (95% CI: 0.72-0.89). LF detected by either method was associated with EKD independently of established renal risk factors and potential confounders. CONCLUSION: LF was independently associated with EKD in patients with biopsy-proven NAFLD. Thus, TE-measured LSM, a widely used technique for quantifying LF, can accurately identify those patients with NAFLD who are at risk of having EKD.

Screening for non-alcoholic fatty liver disease using liver stiffness measurement and its association with chronic kidney disease and cardiovascular complications in patients with type 2 diabetes.

AIM: Despite the high prevalence and serious clinical implications of non-alcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM), NAFLD is usually overlooked during routine diabetes care. This study explored the proportion of NAFLD cases and increased liver fibrosis (LF), and the association between LF and either chronic kidney disease (CKD) or cardiovascular complications in T2DM patients. METHODS: The study included 137 patients with non-insulin-treated T2DM and no known liver disease consecutively attending our diabetes outpatients' service who underwent liver ultrasonography and liver stiffness measurement (LSM) using vibration-controlled transient elastography (FibroScan®). RESULTS: The proportion of patients with hepatic steatosis on ultrasonography was 73.7%, and the proportion with significant LF was 17.5% with an LSM cut-off ≥7kPa or 10.2% with an LSM cut-off ≥8.7kPa. The presence of CKD (estimated GFR <60mL/min/1.73m2 and/or abnormal albuminuria) increased significantly across LSM tertiles (from around 15% in tertile 1 to 45% in tertile 3). Cardiovascular complications (previous ischaemic heart disease, ischaemic stroke, permanent atrial fibrillation) also tended to increase across LSM tertiles (from around 15% to 30%). After adjusting for established risk factors and potential confounders, LSM tertile 3 remained significantly associated with an approximately threefold higher risk of prevalent CKD (adjusted OR: 3.28, 95% CI: 1.22-8.90; P=0.019), but not for cardiovascular complications. CONCLUSION: These results suggest that NAFLD and significant LF (as assessed by FibroScan®) are very commonly seen in T2DM outpatients with no known liver disease attending a secondary-care diabetes service, and that increased LF is associated with a greater proportion of chronic vascular complications, especially CKD.

Association between non-alcoholic fatty liver disease and decreased lung function in adults: A systematic review and meta-analysis.

AIM: Recent observational studies assessed the association between non-alcoholic fatty liver disease (NAFLD) and lung function in adults, but the magnitude of this association remains uncertain. We estimated the magnitude of the association between NAFLD and lung function on spirometry (predicted forced expiratory volume in 1 s [FEV1] and forced vital capacity [FVC]). METHODS: We searched publication databases using predefined keywords to identify studies (published up to October 4, 2018), in which NAFLD was diagnosed by imaging or biochemistry (no studies with biopsy-proven NAFLD were available). Data from selected studies were extracted, and meta-analysis was performed using random-effects modelling. RESULTS: Six observational studies (5 cross-sectional and 1 longitudinal) with aggregate data on 133,707 individuals (27.8% with NAFLD) of predominantly Asian ethnicity (74.6%) were included in the final analysis. There were significant differences in predicted FEV1 (n = 5 studies; pooled weighted mean difference [WMD]: -2.43%, 95% CI: -3.28 to -1.58; I2 = 69.7%) and predicted FVC (pooled WMD: -2.96%, 95% CI: -4.75 to -1.17; I2 = 91.7%) between individuals with and without NAFLD. Decreased FEV1 and FVC at baseline were also independently associated with a ∼ 15% increased risk of incident NAFLD (n = 1 study in Korean individuals). Subgroup analyses did not materially modify these findings. CONCLUSIONS: NAFLD is associated with significant reductions of both FEV1 and FVC in Asian and United States adults, and such small, but significant, reductions of lung volumes at baseline may be also associated with increased NAFLD incidence in Asian individuals. Further research is needed to better elucidate the link between NAFLD and impaired lung volumes.

Type 2 Diabetes and Hepatocellular Carcinoma: Risk Factors and Pathogenesis.

PURPOSE OF REVIEW: This review aims to assess the epidemiological evidence for a link between type 2 diabetes and hepatocellular carcinoma and to investigate possible pathophysiological mechanisms. RECENT FINDINGS: The presence of type 2 diabetes significantly increases the risk of developing hepatocellular carcinoma, and treatment with metformin may be associated with a lower risk. Treatment with insulin and sulphonylureas may be associated with increased risk. The pathophysiology underlying development of hepatocellular carcinoma in this context is complex and is likely to involve increased proinflammatory mediators, oxidative stress, JNK-1 activation, increased IGF-1 activity, altered gut microbiota and immunomodulation. Hepatocellular carcinoma incidence is increasing and this is likely to be linked to the increasing incidence of type 2 diabetes, obesity and the metabolic syndrome. These conditions increase the risk of developing hepatocellular carcinoma, and a greater understanding of the underlying pathophysiology may help with the development of novel treatments.

MNK1 and MNK2 mediate adverse effects of high-fat feeding in distinct ways.

The MAP kinase-interacting kinases (MNK1 and MNK2) are non-essential enzymes which are activated by MAP kinases. They are implicated in controlling protein synthesis. Here we show that mice in which the expression of either MNK1 or MNK2 has been knocked out (KO) are protected against adverse effects of high-fat feeding, and in distinct ways. High-fat diet (HFD)-fed MNK2-KO show less weight gain than wild-type animals, and improved glucose tolerance, better insulin sensitivity and markedly diminished adipose tissue inflammation. This suggests MNK2 plays a role in adipogenesis and/or lipogenesis and in macrophage biology. MNK1-KO/HFD mice show better glucose tolerance and insulin sensitivity, but gain weight and show similar adipose inflammation to WT animals. These data suggest MNK1 participates in mediating HFD-induced insulin resistance. Our findings reveal distinct roles for the MNKs in a novel area of disease biology, metabolic dysfunction, and suggests they are potential new targets for managing metabolic disease.

Design and rationale of the WELCOME trial: A randomised, placebo controlled study to test the efficacy of purified long chainomega-3 fatty acid treatment in non-alcoholic fatty liver disease [corrected].

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) represents a range of liver conditions from simple fatty liver to progressive end stage liver disease requiring liver transplantation. NAFLD is common in the population and in certain sub groups (e.g. type 2 diabetes) up to 70% of patients may be affected. NAFLD is not only a cause of end stage liver disease and hepatocellular carcinoma, but is also an independent risk factor for type 2 diabetes and cardiovascular disease. Consequently, effective treatments for NAFLD are urgently needed. OBJECTIVES: The WELCOME study is testing the hypothesis that treatment with high dose purified long chain omega-3 fatty acids will have a beneficial effect on a) liver fat percentage and b) two histologically validated algorithmically-derived biomarker scores for liver fibrosis. DESIGN: In a randomised double blind placebo controlled trial, 103 participants with NAFLD were randomised to 15-18months treatment with either 4g/day purified long chain omega-3 fatty acids (Omacor) or 4g/day olive oil as placebo. Erythrocyte percentage DHA and EPA enrichment (a validated proxy for hepatic enrichment) was determined by gas chromatography. Liver fat percentage was measured in three discrete liver zones by magnetic resonance spectroscopy (MRS). We also measured body fat distribution, physical activity and a range of cardiometabolic risk factors. METHODS: Recruitment started in January 2010 and ended in June 2011. We identified 178 potential participants, and randomised 103 participants who met the inclusion criteria. The WELCOME study was approved by the local ethics committee (REC: 08/H0502/165; www.clinicalTrials.gov registration number NCT00760513).

Late effects of childhood cancer treatment: severe hypertriglyceridaemia, central obesity, non alcoholic fatty liver disease and diabetes as complications of childhood total body irradiation.

BACKGROUND: Childhood cancer survivors may develop a number of endocrine complications linked to organ failure, such as hypogonadism, diabetes and growth hormone deficiency. However, increasing evidence now suggests that total body irradiation treatment, specifically, is linked with future risk of insulin resistance, hepatic steatosis and dyslipidaemia, possibly because total body irradiation affects adipocyte differentiation and impairs subcutaneous adipose tissue depot expansion during times of positive energy balance. CASE REPORT: We describe a 20-year-old woman who developed pancreatitis with severe hypertriglyceridaemia (serum triglycerides > 300 mmol/l) that required plasmapheresis. She had received total body irradiation prior to her bone marrow transplant at age 6 years for relapsed acute lymphoblastic leukaemia. She developed ovarian failure at age 12 years. At age 15 years she was noted to have hyperglycaemia, increased blood pressure, hepatic steatosis and mild hypertriglyceridaemia. She presented with severe hypertriglyceridaemia and eruptive xanthoma, and developed pancreatitis 12 h after admission. She was treated with plasmapheresis and intravenous insulin and made an excellent recovery. We implicate and discuss total body irradiation as the major contributing factor to her severe hypertriglyceridaemia, compounded by worsening glycaemic control, oestrogen deficiency and a changing adult lifestyle. CONCLUSION: Children who have received total body irradiation are at risk of diabetes and an exaggerated form of the metabolic syndrome with hypertriglyceridaemia, which can be life-threatening. We suggest that survivors of total body irradiation treatment require careful lifelong monitoring of their metabolic status.

Dorothy Hodgkin Lecture 2012: non-alcoholic fatty liver disease, insulin resistance and ectopic fat: a new problem in diabetes management.

Non-alcoholic fatty liver disease is now recognized as the hepatic component of the metabolic syndrome. Non-alcoholic fatty liver disease is a spectrum of fat-associated liver conditions that can result in end-stage liver disease and the need for liver transplantation. Simple steatosis, or fatty liver, occurs early in non-alcoholic fatty liver disease and may progress to non-alcoholic steatohepatitis, fibrosis and cirrhosis with increased risk of hepatocellular carcinoma. Prevalence estimates for non-alcoholic fatty liver disease range from 17 to 33% in the general populations and it has been estimated that non-alcoholic fatty liver disease exists in up to 70% of people with Type 2 diabetes. Non-alcoholic fatty liver disease increases risk of Type 2 diabetes and cardiovascular disease. In people with Type 2 diabetes, non-alcoholic fatty liver disease is the most frequent cause (∼80%) of fatty liver diagnosed by ultrasound. As non-alcoholic fatty liver disease is strongly associated with insulin resistance, the presence of non-alcoholic fatty liver disease with diabetes often contributes to poor glycaemic control. Consequently, strategies that decrease liver fat and improve whole-body insulin sensitivity may both contribute to prevention of Type 2 diabetes and to better glycaemic control in people who already have developed diabetes. This review summarizes the Dorothy Hodgkin lecture given by the author at the 2012 Diabetes UK annual scientific conference, proposing that fatty acid fluxes through the liver are crucial for the pathogenesis of non-alcoholic fatty liver disease and for increasing insulin resistance.

Non-alcoholic fatty liver disease and cardiovascular risk: metabolic aspects and novel treatments.

Non-alcoholic fatty liver disease (NAFLD) is usually a silent disease that occurs in a very high proportion of people with features of the metabolic syndrome, including overweight, insulin resistance and type 2 diabetes. Because obesity and type 2 diabetes are now extremely common in Westernised societies, it is likely that the prevalence of NAFLD increases markedly in the future. Although previously it was thought that NAFLD was harmless, it is now recognised that NAFLD can be a progressive liver condition that increases risk of cirrhosis, end-stage liver disease and hepatocellular carcinoma. Additionally, liver fat accumulation causes insulin resistance and increases risk of type 2 diabetes. Increasing evidence now shows NAFLD is a risk factor for cardiovascular disease (CVD). The purpose of this review is to briefly discuss the pathogenesis of NAFLD, to describe the relationship between NAFLD and CVD and the mechanisms linking both conditions and to discuss some of the treatment options (including lifestyle, nutrition and drugs) that may influence both NAFLD and risk of CVD.

Clinical and laboratory diagnosis of the metabolic syndrome.

The epidemic of obesity is largely responsible for the high prevalence of metabolic syndrome in the developed world. Since 2001 with the development of the NCEP metabolic syndrome classification, simple pragmatic criteria have been available that can be applied in primary care across all continents to diagnose the syndrome. Although there is an ongoing debate about the level of thresholds that should be applied to individual features of the syndrome, it is likely that with further research a consensus will be reached in the near future. It is now clear that metabolic syndrome represents a condition of insulin resistance and ectopic fat accumulation associated with a proinflammatory and procoagulant phenotype. The syndrome is sometimes associated with other conditions such as non-alcoholic fatty liver disease (NAFLD), polycystic ovary syndrome, type 2 diabetes and cardiovascular disease. The purpose of this review is to discuss the clinical and laboratory diagnosis of the metabolic syndrome. The review discusses the various approaches to the investigation of people with the metabolic syndrome. Simple tools for clinical and laboratory diagnosis of metabolic syndrome are described. Some of the more complex biochemical tests that are now being applied in research to the diagnosis of associated conditions, such as NAFLD, are also described.

Grip strength and the metabolic syndrome: findings from the Hertfordshire Cohort Study.

INTRODUCTION: Sarcopenia, the loss of muscle mass and strength with age, is significantly associated with type 2 diabetes in older people. AIM: To determine whether there is a relationship between grip strength and features of the metabolic syndrome. DESIGN: Cross-sectional study. METHODS: Data were collected on grip strength, fasting glucose, triglycerides and HDL cholesterol, blood pressure, waist circumference and 2 h glucose after an oral glucose tolerance test, in a population-based sample of 2677 men and women aged 59-73 years. RESULTS: In men and women combined, a standard deviation (SD) decrease in grip strength was significantly associated with higher: fasting triglycerides (0.05 SD unit increase, 95%CI 0.02-0.09, p = 0.006); blood pressure (OR 1.13, 95%CI 1.04-1.24, p = 0.004); waist circumference (0.08 SD unit increase, 95%CI 0.06-0.10, p < 0.001); 2 h glucose (0.07 SD unit increase, 95%CI 0.03-0.11, p = 0.001) and HOMA resistance (0.05 SD unit increase, 95%CI 0.01-0.09, p = 0.008), after adjustment for gender, weight, age, walking speed, social class, smoking habit and alcohol intake. Lower grip strength was also significantly associated with increased odds of having the metabolic syndrome according to both the ATPIII (OR 1.18, 95%CI 1.07-1.30, p < 0.001) and IDF definitions (OR 1.11, 95%CI 1.01-1.22, p = 0.03). DISCUSSION: Our findings suggest that impaired grip strength is associated with the individual features, as well as with the overall summary definitions, of the metabolic syndrome. The potential for grip strength to be used in the clinical setting needs to be explored.

Early mortality from the time of diagnosis of Type 2 diabetes: a 5-year prospective cohort study with a local age- and sex-matched comparison cohort.

AIMS: To study patterns and predictors of early mortality in individuals with a new diagnosis of Type 2 diabetes, compared with a local age- and sex-matched comparison cohort. METHODS: A total of 736 individuals diagnosed with Type 2 diabetes between 1 May 1996 and 30 June 1998 and non-diabetic age- and sex-matched control subjects were studied. Follow-up was 5.25 years. Age- and gender-specific all-cause mortality odds ratios were calculated for the diabetic cohort compared with the non-diabetic comparator group. Mortality odds ratios were ascertained using conditional logistic regression. RESULTS: There were 147 deaths in the diabetic cohort [cardiovascular (42.2%), cancer (21.1%)]. Compared with the non-diabetic cohort, mortality odds more than doubled [odds ratio (OR) 2.47; 95% confidence interval (CI) 1.74, 3.49]. These increased odds were present in all age bands (including those aged > 75 years at diagnosis) for both cardiovascular and non-cardiovascular causes. In women, a new diagnosis of Type 2 diabetes was associated with a sevenfold increase in mortality odds in those aged 60-74 years (OR 7.00; 95% CI 2.09, 23.47). CONCLUSIONS: Type 2 diabetes is associated with a 2.5-fold increase in the odds of mortality in both men and women over the first 5 years from diagnosis. Our data strongly support the contention that the mortality risk associated with Type 2 diabetes essentially exists from, or may even predate, the time of diagnosis.

Cancer, cardiovascular disease and diabetes mortality among women with a history of endometrial cancer.

Among 7182 women with endometrial cancer in Scotland, standardised mortality ratios (and 95% confidence intervals (CI)) were 6.38 (5.74-7.15) for all cancers and 1.10 (1.00-1.22) for circulatory diseases as underlying cause of death and 2.81 (2.19-3.70) for diabetes as underlying/contributory cause of death.

Variants in the APOC3 promoter insulin responsive element modulate insulin secretion and lipids in middle-aged men.

Variation in the insulin responsive element (IRE) of the APOC3 promoter has been shown to be associated with insulin and glucose concentrations after an oral glucose tolerance test (OGTT) in young healthy men. We evaluated two variants in the IRE (-455T>C and -482C>T) in the Ely study, a prospective cohort study of middle-aged men (n=223) and women (n=279), to determine if the effect of these variants on glucose homeostasis could be explained by altered nonesterified fatty acid (NEFA) levels and if these effects are modulated by age and gender. Both variants had significant effects on the 30-min insulin incremental response in men alone (-482C>T, P=0.007; -455T>C, P=0.0155), with rare allele homozygotes having a 33.3% and 23.3% lower insulin increment as compared to common allele homozygotes, respectively. Thirty-minute NEFA concentrations were also significantly associated with genotype in men and levels were approximately 10% higher in carriers homozygous for the rare alleles as compared to subjects homozygous for the common alleles (-482C>T, P=0.04; -455T>C, P=0.006). In addition, there was a strong interaction between both variants and cigarette smoking affecting fasting triglyceride levels in both men (interaction: -455T>C, P=0.02; -482C>T, P=0.008) and women (interaction: -455T>C, P=0.007; -482C>T, P=0.013). Taken together, the data shows that men who carry the rare alleles of the IRE variants have disturbed glucose homeostasis and an unfavourable lipid phenotype. The finding of an elevated 30-min NEFA may be an important mechanistic link between triglyceride-rich lipoprotein (TRL) metabolism and glucose homeostasis.

Suppressing thrombin generation is compatible with the development of atherosclerosis in mice.

Thrombin has been proposed to play a key role in the development of atherosclerosis, both by promoting fibrin deposition into the atherosclerotic vessel wall and also by signalling through thrombin receptors. Unfortunately, mice homozygous for a deletion of the prothrombin gene (FII) die in utero, making a direct assessment of the role of thrombin during atherogenesis difficult. We have assessed the contribution of thrombin-dependent processes to vascular lipid lesion formation in the atherosclerosis-prone apolipoprotein E (ApoE)-deficient mice by inhibiting thrombin generation with warfarin. ApoE-/- mice were treated with warfarin at a dose that increased the prothrombin time (PT) more than 10-fold (250-375 microg/kg body weight/day) for 12 weeks from the age of 12 weeks onwards. The extent and composition of the vascular lipid lesions that developed were assessed using oil red O to measure neutral lipid in the vessel wall and quantitative immunofluoresence to measure fibrin(ogen) levels as well as macrophage and smooth muscle cell numbers. Mice treated with warfarin developed lesions both in the aortic sinus and the descending aorta to the same degree as mice receiving no treatment (28,351+/-350 microm2/mouse treated with warfarin versus 27,952+/-750 micro2/control mouse; P = .86). However, the amount of fibrin(ogen) deposited in the vessel wall was decreased by more than 60% (34+/-11 arbitrary units in warfarin treated mice versus 92+/-11 arbitrary units in control mice; P < .01). Staining of macrophage and for smooth muscle cell markers was unaltered by treatment with warfarin. We conclude that suppressing thrombin generation does not alter the development of vascular lipid lesions in mice with a severe disorder of lipid metabolism, despite a marked reduction in fibrin(ogen) deposition.

Effects of maternal iron restriction in the rat on hypoxia-induced gene expression and fetal metabolite levels.

The mechanism by which maternal Fe deficiency in the rat causes fetal growth retardation has not been clearly established. This study compared the effects on the fetuses from dams fed a control diet with two groups of dams fed Fe-restricted diets. One Fe-restricted group was fed the Fe-restricted diet for 1 week prior to mating and throughout gestation and the second Fe-restricted group was fed the Fe-restricted diet for 2 weeks prior to mating and throughout gestation. On day 21 of gestation Fe-restricted dams, and their fetuses, were anaemic. Fetal weight was reduced in both Fe-restricted groups compared with controls. Expression of hypoxia-inducible factor (HIF)-1alpha and vascular endothelial growth factor (VEGF) are induced by hypoxia. The levels of HIF-1alpha mRNA were highest in placenta, then in kidney, heart and liver but were not different between the groups. Levels of plasma VEGF were not different between the groups. Maternal plasma triacylglycerol was decreased in the 1-week Fe-restricted dams compared with controls. Maternal plasma cholesterol and free fatty acid levels were not different between the groups. In fetal plasma, levels of triacylglycerol and cholesterol were decreased in both Fe-restricted groups. In maternal plasma, levels of a number of amino acids were elevated in both Fe-restricted groups. In contrast, levels of a number of amino acids in fetal plasma were lower in both Fe-restricted groups. Fetal plasma lactate was increased in Fe-restricted fetuses but fetal plasma glucose and beta-hydroxybutyrate were not affected. These changes in fetal metabolism may contribute to fetal growth retardation in this model. This study does not support the hypothesis that the Fe-restricted fetus is hypoxic.