Normal Plasma Cholesterol Research Articles

Obeticholic acid ameliorates dyslipidemia but not glucose tolerance in mouse model of gestational diabetes.

Metabolism alters markedly with advancing gestation, characterized by progressive insulin resistance, dyslipidemia, and raised serum bile acids. The nuclear receptor farnesoid X receptor (FXR) has an integral role in bile acid homeostasis and modulates glucose and lipid metabolism. FXR is known to be functionally suppressed in pregnancy. The FXR agonist, obeticholic acid (OCA), improves insulin sensitivity in patients with type 2 diabetes with nonalcoholic fatty liver disease. We therefore hypothesized that OCA treatment during pregnancy could improve disease severity in a mouse model of gestational diabetes mellitus (GDM). C57BL/6J mice were fed a high-fat diet (HFD; 60% kcal from fat) for 4 wk before and throughout pregnancy to induce GDM. The impact of the diet supplemented with 0.03% OCA throughout pregnancy was studied. Pregnant HFD-fed mice displayed insulin resistance and dyslipidemia. OCA significantly reduced plasma cholesterol concentrations in nonpregnant and pregnant HFD-fed mice (by 22.4%, P < 0.05 and 36.4%, P < 0.001, respectively) and reduced the impact of pregnancy on insulin resistance but did not change glucose tolerance. In nonpregnant HFD-fed mice, OCA ameliorated weight gain, reduced mRNA expression of inflammatory markers in white adipose tissue, and reduced plasma glucagon-like peptide 1 concentrations (by 62.7%, P < 0.01). However, these effects were not evident in pregnant mice. OCA administration can normalize plasma cholesterol levels in a mouse model of GDM. However, the absence of several of the effects of OCA in pregnant mice indicates that the agonistic action of OCA is not sufficient to overcome many metabolic consequences of the pregnancy-associated reduction in FXR activity.

Simvastatin reduces circulating oxysterol levels in men with hypercholesterolaemia

Oxysterols (OHC) are biologically active cholesterol metabolites circulating in plasma that may be formed enzymatically (e.g. 24S-OHC, 25-OHC and 27-OHC) or by autoxidative mechanisms (e.g. 7-ketocholesterol, 7β-OHC and 25-OHC). Oxysterols are more soluble than cholesterol and are reported to exert inflammatory, cytoprotective and apoptotic effects according to concentration and species. Esterified oxysterols have been analysed in people with dementia and cardiovascular diseases although there is no consistent relationship between oxysterol esters and disease. However, oxysterol esters are held in lipoprotein core and may not relate to the concentration and activity of plasma free oxysterols. Methodological limitations have challenged the analysis of free oxysterols to date.We have developed a fast, sensitive and specific quantitative LC-MS/MS, multiple reaction monitoring (MRM) method to target five oxysterols in human plasma with analyte recoveries between 72% and 82% and sensitivities between 5 and 135 pg/ml. A novel method was used to investigate the hypothesis that simvastatin may reduce the concentrations of specific plasma free oxysterols in hypercholesterolaemia.Twenty healthy male volunteers were recruited (aged 41–63 years); ten were asymptomatic with high plasma cholesterol > 6.5 mM and ten were healthy with normal plasma cholesterol (< 6.5 mM). Simvastatin (40 mg/day) was prescribed to those with hypercholesterolaemia. Plasma samples were taken from both groups at baseline and after three months. Simvastatin reduced plasma cholesterol by ~35% (p < 0.05) at the end of three months.Oxysterols generated by autoxidation (but not enzymatically) were elevated up to 45 fold in hypercholesterolaemic midlife men. Plasma oxysterols were restored to those of healthy controls after simvastatin intervention suggesting that autoxidation is either prevented by simvastatin directly or that autoxidation is less prevalent when plasma cholesterol concentrations are within the normal range.

Leukocyte ABCA1 impedes progression of established atherosclerotic lesions after dietary cholesterol lowering in LDLr-/- mice

The ATP-binding cassette transporter A1 (ABCA1) facilitates the efflux of cholesterol and phospholipids to lipid-free apolipoprotein A1 and small dense high-density lipoproteins. Various studies have shown that leukocyte ABCA1 is an anti-atherogenic factor. Dietary cholesterol lowering stabilizes atherosclerotic lesions, however the role of ABCA1 in this process is unknown. Therefore, this study aims to investigate the effect of leukocyte ABCA1 on diet-induced atherosclerotic lesions after withdrawal of the atherogenic diet . Leukocyte ABCA1 was studied by transplanting bone marrow cells from donor mice that were either knock-out (ABCA1-/-) or wild-type for ABCA1 or that overexpressed ABCA1 (ABCA1Tg) into low-density lipoprotein receptor knock-out (LDLr-/-) mice. All three groups of chimeric mice were fed a Western-type diet (WTD: 0.25%cholesterol, 15Ecao butter) for 6 weeks to induce atherosclerotic lesion development. After this period, a baseline group was sacrificed (ABCA1-/- >LDLr-/- n=12; wild-type >LDLr-/- n=14; ABCA1Tg >LDLr-/- n=9) for lesion assessment. The remainder of chimeric mice was switched to a chow diet (low fat, no added cholesterol) for 3 weeks to lower plasma cholesterol levels (ABCA1-/- >LDLr-/- n=14; wild-type >LDLr-/- n=14; ABCA1Tg >LDLr-/- n=12).Withdrawal of the atherogenic diet normalized plasma cholesterol levels in all three groups. As a result, lesion development was stabilized in both the wild-type >LDLr-/- and ABCA1Tg >LDLr-/- mice, however not in the ABCA1-/- >LDLr-/- mice, which displayed a 1.5-fold increase (p Leukocyte ABCA1 is required to halt atherosclerotic lesion progression after dietary cholesterol lowering. Overexpression of ABCA1 did not result in any additional beneficial effects.

Type 3 diabetes with links to NAFLD and Other Chronic Diseases in the Western World

In the year 2015 it is now estimated that 30% of the Western World will now progress to non alcoholic fatty liver disease (NAFLD) and by the year 2050 if NAFLD remains untreated in the Western world the prevalence of the disease may rise to 40% of the global population. Type 3 diabetes and circadian rhythm disturbances may be involved in the induction of NAFLD that may promote insulin resistance and various chronic diseases such as cardiovascular disease, pancreatic disease, kidney disease and neurodegenerative disease. Multiple risk factors that induce Type 3 diabetes and NAFLD include stress, magnesium deficiency, bacterial lipopolysaccharide contamination, drug induced toxicity, xenobiotic levels, unhealthy diet/lifestyle factors and defective thermoregulation. Early diagnosis of Type 3 diabetes by multiple assessment techniques such as proteomics, genomics and lipidomics may allow reversal or stabilization of NAFLD that may progress slowly from simple non-alcoholic steatosis to non-alcoholic steatohepatitis and to hepatic fibrosis/cirrhosis of liver and hepatoma. Analysis of plasma constituents such as heat shock proteins (60,70, 90), amyloid beta, adiponectin, fibroblast growth factor 21, ceramide, sphingosine1-phosphate, vasoactive intestinal peptide, thrombospondin 1, acute phase reactants may indicate progression of Type 3 diabetes and NAFLD and these results may not be consistent with normal plasma glucose and cholesterol levels. Early nutritional interventions with temperature regulation are required to reverse premature brain disease in diabetes (Type 3/Type2) that is connected to the rapid metabolism of heat shock proteins and amyloid beta oligomers that determine the severity of insulin resistance and NAFLD in individuals in the Western World.

Avaliação antropométrica, pressórica e hematológica de população vegetariana

Objetivo: Evaluar los índices antropométricos, los niveles de presión arterial y resultados de análisis hematológicos de la población vegetariana del municipio de Ji-Paraná, Rondônia. &lt;br /&gt;&lt;br /&gt;Método: Se trata de un estudio descriptivo y cuantitativo, de corte transversal, con muestra compuesta por 65 personas vegetarianas.&lt;br /&gt; &lt;br /&gt;Resultados: Se identificó 61,6% de eutróficos, 69,2% con circunferencia abdominal dentro de los parámetros normales, 92,3% presentaron niveles de presión arterial normales y 26,2% fueron clasificados como anémicos. Más del 60% de los vegetarianos presentaron niveles plasmáticos de colesterol (Total y LDL) y calcio dentro de los parámetros normales. Lo mismo se observó en relación a los triglicéridos (81,4%), glicemia (96,9%), proteínas totales (93,9%) y albúmina (100%). &lt;br /&gt;&lt;br /&gt;Conclusión: Se concluye que la alimentación vegetariana diversificada puede proporcionar beneficios a la salud del ser humano.&lt;br /&gt;&lt;br /&gt;

Body girdle reduced fat deposition and altered other body parameters in rats.

Many women favor in wearing foundation garments to shape their body and show satisfactory figures. However, few investigations have been conducted on the physiological impact of wearing tight garments on the body. In this study, we used girdled rats that were fed with a high fat diet to investigate their physiological condition including alterations in food intake, body weight, fat deposition, and hormone concentrations. Over the experiment period, girdled rats maintained normal plasma and liver cholesterol and triglyceride. Leptin level in girdled rats was significantly lower than that in normal control. The fat tissue of girdled rats was more active in secretion of leptin, which might be mediated by mTOR signaling. Girdled rats showed no difference in hematology analysis during the experiment period. This study showed that a body girdle can significantly reduce fat deposition and alter other body parameters in rats.

Effects of surgically implanted dummy ultrasonic transmitters on physiological response of bighead carp Hypophthalmichthys nobilis.

The study assessed the effects of surgically implanted dummy ultrasonic transmitters on physiological response of bighead carp Hypophthalmichthys nobilis in April 2011. Before the surgery, 15 blood samples were extracted randomly from 195 bighead carp samples, and then the rest of the fish were divided into three groups: (1) control group, handing but no tagging, (2) sham group, surgical procedure without implantation of transmitter and (3) surgery group, surgical implantation of transmitters. In 3 h, 24 h, 7 days and 14 days after surgery, 15 fish were extracted randomly from the three groups, respectively, for sampling. Then the plasma samples were analyzed, and physiological measures of stress response (cortisol, glucose), tissue damage [alanine aminotransferase (ALT) and aspartate aminotransferase (AST)] and nutritional status [total protein, globulin, albumin, triglyceride, cholesterol, and alkaline phosphatase (ALP)] were compared. The result showed that there was no significant difference between sham and surgery groups in 3 h, 24 h, 7 days and 14 days after surgery. When compared to the control group, there were significant increases in concentrations of plasma cortisol, glucose, ALT, AST, total protein and globulin of sham and surgery groups in 3 h after surgery. After 24 h, the levels of plasma cortisol, ALT, AST, total protein, globulin and ALP were elevated in both sham and surgery groups, whereas the levels of plasma glucose had declined to normal level and plasma albumin, cholesterol and triglyceride were significantly decreased in both sham and surgery groups. After 7 days, the levels of plasma glucose, albumin and cholesterol continued to decline, while the level of plasma ALT, globulin and ALP had declined but still remained higher for sham and surgery groups than control group; however, the plasma total protein level had returned to normal. After 14 days, there was no significant difference between the three groups. The above results showed that surgical implantation of ultrasonic transmitters had indeed caused significantly negative effects on the physiological response of bighead carp. However, all the negative influences on stress response, tissue damage and nutritional status had disappeared in 14 days after surgery, and the presence of transmitters had no significant negative impact. Therefore, the bighead carp should be temporary cultured at least 14 days for the recovery of physiological response and then released into the free water for the ultrasonic telemetry research.

Lipoproteins and β-Cell Functions: From Basic to Clinical Data.

Lipoproteins and β-Cell Functions: From Basic to Clinical Data.

943 Gastric Bypass Surgery for Morbid Obesity Disrupts Entero-Pancreatic Physiology

G A A b st ra ct s synthesis, and third in terms of fatty acid synthesis (behind adipose and liver). Although the role of Insigs in regulating hepatic lipid metabolism is known, their role in the intestine is unknown. AIM: To study the role of Insig proteins on the regulation of lipid synthesis in the small intestine. METHODS: Mice with germline disruption of Insig2 and Villin-Cre mediated disruption of Insig1 in the intestine were generated (designated Vil-Insig mice). Tissues and plasma were harvested. Enterocytes were isolated and fractionated for immunoblotting, which was quantified by densitometry. mRNAs were quantified by qPCR. Plasma lipids were measured using a Vitros 250 chemistry analyzer. Jejuna were cryosectioned and stained with oil red O. RESULTS: The deletion of Insigs in intestine resulted in a loss of the normal feedback inhibition of SREBP processing and of HMGR proteolysis. Enterocyte nuclear SREBP-1 and SREBP-2 levels were increased in the Vil-Insig mice by 5-fold and 8fold, respectively. HMGR protein levels were increased by 18-fold. mRNA levels of SREBP lipogenic target genes were all increased; the greatest of which was stearoyl-CoA desaturase1 mRNA, which was increased 195-fold. As a consequence of this loss of SREBP-feedback inhibition, plasma cholesterol levels in the Vil-Insig mice were increased by 55% (123+/9 mg/dL vs 191+/-6 mg/dL, p,0.0001). Neutral lipid levels were increased in the jejunal crypts of the Vil-Insig mice as evidenced by oil red O staining. CONCLUSION: These studies indicate that the essential elements of the regulatory pathway for lipid synthesis function in the enterocyte as they do in the hepatocyte. Insig proteins provide essential negative feedback regulation on lipid biosynthesis in the intestine, and this regulation is required to maintain normal plasma cholesterol levels. Insigs mediate these effects by negatively regulating SREBPs and HMGR, to affect both cholesterol and fatty acid synthesis. Further studies will be required to determine if the increase in plasma cholesterol seen in the Vil-insig mice is related to changes in chylomicron synthesis/metabolism, and if Insig proteins affect enterocyte development, given the unique finding of lipid accumulation in the intestinal crypts.

Diabetic atherosclerosis in APOE*4 mice: synergy between lipoprotein metabolism and vascular inflammation

Diabetes is a major risk factor for cardiovascular disease. To examine how diabetes interacts with a mildly compromised lipid metabolism, we introduced the diabetogenic Ins2(C96Y/+) (Akita) mutation into mice expressing human apoE4 (E4) combined with either an overexpressing human LDL receptor gene (hLDLR) or the wild-type mouse gene. The hLDLR allele caused 2-fold reductions in plasma HDL-cholesterol, plasma apoA1, and hepatic triglyceride secretion. Diabetes increased plasma total cholesterol 1.3-fold and increased apoB48 secretion 3-fold, while reducing triglyceride secretion 2-fold. Consequently, diabetic E4 mice with hLDLR secrete increased numbers of small, cholesterol-enriched, apoB48-containing VLDL, although they have near normal plasma cholesterol (<120 mg/dl). Small foam cell lesions were present in the aortic roots of all diabetic E4 mice with hLDLR that we analyzed at six months of age. None were present in nondiabetic mice or in diabetic mice without hLDLR. Aortic expression of genes affecting leukocyte recruitment and adhesion was enhanced by diabetes. ApoA1 levels, but not diabetes, were strongly correlated with the ability of plasma to efflux cholesterol from macrophages. We conclude that the diabetes-induced proinflammatory changes in the vasculature and the hLDLR-mediated cholesterol accumulation in macrophages synergistically trigger atherosclerosis in mice with human apoE4, although neither alone is sufficient.

Palm olein increases plasma cholesterol moderately compared with olive oil in healthy individuals

BackgroundDespite the high content of palmitic acid, palm olein was demonstrated to have a neutral effect on plasma cholesterol concentration when compared with olive oil, suggested to be due to palmitic acid in the sn‐1 and sn‐3 position.Objectiveto investigate the effects of a diet rich in palm olein (fractionated palm oil), olive oil and lard on plasma blood lipids, inflammatory markers, glucose and insulin.in a controlled double‐blinded, randomized 3 × 3 weeks crossover dietary intervention study, including 32 healthy men, who daily replaced part of their habitual dietary fat intake with approximately 17 energy percent (E%) from palm olein, olive oil or lard, respectively.ResultsCompared with intake of olive oil, palm olein and lard increased total cholesterol and LDL cholesterol (P &lt; 0.0001). Palm olein resulted in a lower plasma triacylglycerol (TAG) concentration than olive oil (P &lt; 0.01). No difference in effects was observed in plasma HDL cholesterol, high sensitive C‐reactive protein (hsCRP), plasminogen activator 1 (PAI‐1), insulin and glucose concentrations.ConclusionThe present study did not support findings of palm olein being neutral compared to olive oil in regard to total plasma cholesterol and LDL cholesterol in healthy individuals with normal plasma cholesterol concentrations. Thus, the sn‐positioning was not confirmed to be important in regard to effect on plasma cholesterol.

Palm olein increases plasma cholesterol moderately compared with olive oil in healthy individuals

Despite the high content of palmitic acid, palm olein has been shown to have a neutral effect on plasma cholesterol concentrations when compared with olive oil, which is suggested to be attributable to palmitic acid in the sn-1 and sn-3 position. In contrast, palmitic acid is in the sn-2 position in lard. The objective was to investigate the effects of a diet rich in palm olein, fractionated palm oil, olive oil, and lard on plasma blood lipids, inflammatory markers, glucose, and insulin. A controlled double-blinded, randomized 3 × 3 wk crossover dietary intervention study included 32 healthy men who daily replaced part of their habitual dietary fat intake with ~ 17% of energy from palm olein, olive oil, or lard, respectively. Compared with intake of olive oil, palm olein and lard increased total cholesterol and LDL cholesterol (P < 0.0001). Palm olein resulted in a lower plasma triacylglycerol concentration than did olive oil (P < 0.01). No difference in effects was observed in plasma HDL-cholesterol, high-sensitivity C-reactive protein, plasminogen activator-1, insulin, and glucose concentrations. The current study did not support the previous finding that the effect of palm olein on total plasma cholesterol and LDL cholesterol in healthy individuals with normal plasma cholesterol concentrations is neutral compared with that of olive oil. Thus, sn-positioning was not confirmed to be important with regard to the effect on plasma cholesterol. The relatively lower plasma triacylglycerol concentration after the palm olein diet than after the olive oil diet was unexpected. This trial is registered at clinicaltrials.gov as NCT00743301.

Serum adiponectin level is not only decreased in metabolic syndrome but also in borderline metabolic abnormalities

Objective:Along with the increasing prevalence of obesity and related diseases, particularly atherosclerotic diseases, metabolic syndrome (MetS) is now a common and major public health issue in many countries around the world. Adiponectin, a protein secreted by the adipose tissue, has become recognized as a key player in the development of MetS. These days, not only MetS but also borderline metabolic/physiological abnormalities, such as impaired fasting glucose, high normal blood pressure and high normal plasma cholesterol, have been reported to be risk factors for atherosclerotic disease. Therefore, we undertook this study to determine the relationship between adiponectin and borderline metabolic/physiological abnormalities, as well as MetS.Design:A cross-sectional study performed from April 2007 to November 2009.Subjects:In 16 892 Japanese adults (10 008 men and 6884 women), we examined the relationship between the serum adiponectin concentration and borderline metabolic/physiological abnormalities or MetS by a questionnaire survey about medical treatment, body size measurement and measurement of laboratory parameters including the serum adiponectin concentration.Results:Adiponectin showed a significant negative correlation with the number of MetS components. In subjects without overt diabetes mellitus, hypertension or dyslipidemia, the adiponectin concentration also showed a significant negative correlation with the number of borderline metabolic abnormalities.Conclusion:The decrease of circulating adiponectin may start before the development of diabetes mellitus, hypertension, dyslipidemia or MetS. Adiponectin is an important biomarker for reflecting the adverse influence of visceral fat in persons with MetS, and also in these subclinical states.

HDL scavenger receptor class B type I and platelet function

HDL cholesterol levels have been inversely correlated with thrombosis and HDL has been shown to mediate various antithrombotic effects. However, molecular mechanisms underlying the suppressing effect of HDL on platelet reactivity are not completely understood. The present review summarizes the recent advancements in understanding the role played by scavenger receptor class B type I (SR-BI) - an HDL receptor - in modulating platelet function and mediating platelet-HDL interactions. SR-BI is expressed on platelet surface and platelets from SR-BI knockout animals are characterized by increased free-to-total cholesterol ratio, abnormal morphology, increased reactivity to strong platelets agonists, enhanced adherence to immobilized fibrinogen, and a propensity to form arterial thrombi. Crossover incubation experiments and a bone marrow transplantation approach reveal increased wild-type platelet reactivity in plasma from SR-BI mice and normal or decreased SR-BI-deficient platelet reactivity in wild-type plasma. A similar functional platelet phenotype has been observed in human carriers of an SR-BI genetic variant. SR-BI ligands interfere with HDL binding to murine platelets and impede the agonist-induced platelet activation as effectively as native HDL. The inhibitory effects of native HDL, moderately oxidized HDL, and SR-BI ligands are abolished in SR-BI-deficient platelets but not in CD36-deficient platelets. SR-BI exerts an indirect influence on platelet reactivity via maintaining normal plasma cholesterol homeostasis. In addition, SR-BI is a functional receptor for native and moderately oxidized HDL on platelets that generates an inhibitory signal for platelet activation.

Hypolipidemic effect of mustard oil enriched with medium chain fatty acid and polyunsaturated fatty acid

ObjectiveThe hypolipidemic effect of two structured lipids prepared from mustard oil was studied: one was medium chain fatty acid (MCFA) rich mustard oil and the other was polyunsaturated fatty acid (PUFA) rich mustard oil. MethodsThirty-six rats were involved in the study with six rats in each group. Three groups were normal, whereas the others were hypercholesterolemic. Hypolipidemic effects were investigated in both plasma and tissues. ResultsBoth structured lipids with similar content of functional fatty acids (about 19%) were fed (20% of diet weight) to normal and hypercholesterolemic male albino rats. After 28 d of feeding, the fat and protein digestibility increased by administration of the two structured lipids in comparison with the control group fed with normal mustard oil. In both normal and hypercholesterolemic condition plasma cholesterol, non-high-density lipoprotein, and triacylglycerols were reduced by feeding the rats with experimental oils, but the reduction was in lesser amount in rats fed with MCFA-rich mustard oil than in rats fed with PUFA-rich mustard oil and same findings were also seen in hypercholesterolemia. However the HDL levels increased with the administration of both experimental oils. ConclusionMustard oil can be enriched with MCFA and n-3 PUFA and these modified lipids exhibited hypocholesterolemic and hypolipidemic effects in rats when compared to unmodified mustard oil.

Anderson's disease/chylomicron retention disease in a Japanese patient with uniparental disomy 7 and a normal SAR1B gene protein coding sequence

BackgroundAnderson's Disease (AD)/Chylomicron Retention Disease (CMRD) is a rare hereditary hypocholesterolemic disorder characterized by a malabsorption syndrome with steatorrhea, failure to thrive and the absence of chylomicrons and apolipoprotein B48 post-prandially. All patients studied to date exhibit a mutation in the SAR1B gene, which codes for an essential component of the vesicular coat protein complex II (COPII) necessary for endoplasmic reticulum to Golgi transport. We describe here a patient with AD/CMRD, a normal SAR1B gene protein coding sequence and maternal uniparental disomy of chromosome 7 (matUPD7).Methods and ResultsThe patient, one of two siblings of a Japanese family, had diarrhea and steatorrhea beginning at five months of age. There was a white duodenal mucosa upon endoscopy. Light and electron microscopy showed that the intestinal villi were normal but that they had lipid laden enterocytes containing accumulations of lipid droplets in the cytoplasm and lipoprotein-size particles in membrane bound structures. Although there were decreased amounts in plasma of total- and low-density lipoprotein cholesterol, apolipoproteins AI and B and vitamin E levels, the triglycerides were normal, typical of AD/CMRD. The presence of low density lipoproteins and apolipoprotein B in the plasma, although in decreased amounts, ruled out abetalipoproteinemia. The parents were asymptomatic with normal plasma cholesterol levels suggesting a recessive disorder and ruling out familial hypobetalipoproteinemia. Sequencing of genomic DNA showed that the 8 exons of the SAR1B gene were normal. Whole genome SNP analysis and karyotyping revealed matUPD7 with a normal karyotype. In contrast to other cases of AD/CMRD which have shown catch-up growth following vitamin supplementation and a fat restricted diet, our patient exhibits continued growth delay and other aspects of the matUPD7 and Silver-Russell Syndrome phenotypes.ConclusionsThis patient with AD/CMRD has a normal SAR1B gene protein coding sequence which suggests that factors other than the SAR1B protein may be crucial for chylomicron secretion. Further, this patient exhibits matUPD7 with regions of homozygosity which might be useful for elucidating the molecular basis of the defect(s) in this individual. The results provide novel insights into the relation between phenotype and genotype in these diseases and for the mechanisms of secretion in the intestine.

Identification by whole-genome resequencing of gene defect responsible for severe hypercholesterolemia

Whole-genome sequencing is a potentially powerful tool for the diagnosis of genetic diseases. Here, we used sequencing-by-ligation to sequence the genome of an 11-month-old breast-fed girl with xanthomas and very high plasma cholesterol levels (1023 mg/dl). Her parents had normal plasma cholesterol levels and reported no family history of hypercholesterolemia, suggesting either an autosomal recessive disorder or a de novo mutation. Known genetic causes of severe hypercholesterolemia were ruled out by sequencing the responsible genes (LDLRAP, LDLR, PCSK9, APOE and APOB), and sitosterolemia was ruled out by documenting a normal plasma sitosterol:cholesterol ratio. Sequencing revealed 3 797 207 deviations from the reference sequence, of which 9726 were nonsynonymous single-nucleotide substitutions. A total of 9027 of the nonsynonymous substitutions were present in dbSNP or in 21 additional individuals from whom complete exonic sequences were available. The 699 novel nonsynonymous substitutions were distributed among 604 genes, 23 of which were single-copy genes that each contained 2 nonsynonymous substitutions consistent with an autosomal recessive model. One gene, ABCG5, had two nonsense mutations (Q16X and R446X). This finding indicated that the infant has sitosterolemia. Thus, whole-genome sequencing led to the diagnosis of a known disease with an atypical presentation. Diagnosis was confirmed by the finding of severe sitosterolemia in a blood sample obtained after the infant had been weaned. These findings demonstrate that whole-genome (or exome) sequencing can be a valuable aid to diagnose genetic diseases, even in individual patients.

Transport of maternal cholesterol to the fetus is affected by maternal plasma cholesterol concentrations in the Golden Syrian hamster

The fetus has a high requirement for cholesterol and synthesizes cholesterol at elevated rates. Recent studies suggest that fetal cholesterol also can be obtained from exogenous sources. The purpose of the current study was to examine the transport of maternal cholesterol to the fetus and determine the mechanism responsible for any cholesterol-driven changes in transport. Studies were completed in pregnant hamsters with normal and elevated plasma cholesterol concentrations. Cholesterol feeding resulted in a 3.1-fold increase in the amount of LDL-cholesterol taken up by the fetus and a 2.4-fold increase in the amount of HDL-cholesterol taken up. LDL-cholesterol was transported to the fetus primarily by the placenta, and HDL-cholesterol was transported by the yolk sac and placenta. Several proteins associated with sterol transport and efflux, including those induced by activated liver X receptor, were expressed in hamster and human placentas: NPC1, NPC1L1, ABCA2, SCP-x, and ABCG1, but not ABCG8. NPC1L1 was the only protein increased in hypercholesterolemic placentas. Thus, increasing maternal lipoprotein-cholesterol concentrations can enhance transport of maternal cholesterol to the fetus, leading to 1) increased movement of cholesterol down a concentration gradient in the placenta, 2) increased lipoprotein secretion from the yolk sac (shown previously), and possibly 3) increased placental NPC1L1 expression.

Domino liver graft from a patient with homozygous familial hypercholesterolemia

HFH is a metabolic disease caused by a defect in the gene that encodes the synthesis of the cellular receptor for LDL-Rs. A high plasma level of cholesterol is present from birth and leads to severe atherosclerosis in childhood, and death from myocardial infarction usually occurs before the age of 20 yr. The liver contains approximately 50-75% of the total body LDL-Rs; therefore, liver transplantation has been carried out to treat this metabolic disorder effectively. The rationale for using an HFH liver for a domino graft is that the absence of functional LDL-Rs in the liver may be compensated for by the extra-hepatic LDL-Rs. Therefore, an HFH liver can possibly be used as a domino graft for a recipient with a normal plasma cholesterol level before transplantation. We herein report a domino liver transplantation using an HFH liver as a domino graft with successful results. To expand the donor pool, especially in Asian countries, domino grafts from HFH should be encouraged by careful selection of the domino recipient.

Cholestanol metabolism in patients with cerebrotendinous xanthomatosis: absorption, turnover, and tissue deposition

To study the metabolism of cholestanol in patients with cerebrotendinous xanthomatosis (CTX), we measured the cholestanol absorption, the cholesterol and cholestanol turnover, and the tissue content of sterols in two patients. Cholestanol absorption was approximately 5.0%. The rapid exchangeable pool of cholestanol was 233 mg, and the total exchangeable pool was 752 mg. The production rate of cholestanol in pool A was 39 mg/day. [4-14C]cholestanol was detected in the xanthomas, but neither [4-14C]cholestanol nor [4-14C]cholesterol was detected in peripheral nerves biopsied at 49 and 97 days after [4-14C]cholesterol given intravenously. Of the 18 tissues analyzed at biopsy and autopsy, the cholestanol content varied from 0.09 mg/g in psoas muscle to 76 mg/g in a cerebellar xanthoma. With the assumption that the cholestanol-to-cholesterol ratio is 1.0, the relative cholestanol-to-cholesterol ratio varied from 1.0 in plasma and liver to 30.0 in the cerebellar xanthoma; cholestanol was especially high in nerve tissue. Our data indicate that CTX patients absorb cholestanol from the diet. They have a higher than normal cholestanol production rate. Cholestanol was derived from cholesterol. In CTX patients, the blood-brain barrier was intact to the passage of [4-14C]cholesterol and [4-14C]cholestanol. The deposition of large amounts of cholestanol (up to 30% of total sterols in cerebellum) in nerve tissues must have an important role in the neurological symptoms in CTX patients. In view of the intact blood-brain barrier, several other explanations for the large amounts of cholestanol in the brain were postulated.