Cholesterol metabolism altered and FGF21 levels high after pediatric liver transplantation despite normal serum lipids

Liver transplantation (LT) predisposes to metabolic derangements and increases the risk for cardiovascular disease. We conducted a national cross-sectional study of all pediatric recipients who underwent LT between 1987 and 2007. We measured serum levels of noncholesterol sterols (surrogate markers of cholesterol synthesis and intestinal absorption) and fibroblast growth factor 21 (FGF21) in 49 patients (74% of survivors) at a median of 10 years posttransplant and in 93 controls matched for age and gender. Although serum cholesterol levels were similar in patients and controls, patients displayed increased whole-body synthesis and decreased intestinal absorption of cholesterol compared with controls (lathosterol to cholesterol ratio 129 ± 55 vs. 96 ± 41, respectively, p < 0.001; campesterol to cholesterol ratio 233 ± 91 vs. 316 ± 107, respectively; p < 0.001). Azathioprine (r =-0.383, p = 0.007) and low-dose methylpredisolone (r =-0.492, p < 0.001) were negatively associated with lathosterol/sitosterol ratio reflecting a favorable effect on cholesterol metabolism. FGF21 levels were higher in patients than in controls (248 pg/mL vs. 77 pg/mL, p < 0.001). In healthy controls, FGF21 was associated with cholesterol metabolism, an association missing in LT recipients. Normal serum lipids are achievable in long-term survivors of pediatric LT, but changes in cholesterol metabolism and increased FGF21 levels may explicate later cardiovascular risk.

Definition of frailty in older men according to questionnaire data (RAND-36/SF-36): The Helsinki Businessmen Study

OBJECTIVE

To explore the association of frailty according to questionnaire data (modified Fried criteria) with important endpoints in older men.

DESIGN AND SETTING

Prospective cohort study (the Helsinki Businessmen Study) in Finland.

PARTICIPANTS AND MEASUREMENTS

In 1974, clinically healthy men (born 1919-1934, n=1815) of similar socioeconomic status were identified. After a 26-year follow-up in 2000 (mean age 73 years), disease prevalence, mobility-disability, and frailty status (80.9% of survivors, n=1125) were appraised using a postal questionnaire including RAND-36. Four criteria were used for definition: 1) >5% weight loss from midlife, or body mass index (BMI) <21 kg/m2; 2) reported physical inactivity; 3) low vitality (RAND-36); 4) physical weakness (RAND-36). Responders with 3-4, 1-2, and zero criteria were classified as frail (n=108), prefrail (n=567), and nonfrail (n=450), respectively. Eight-year mortality was assessed from registers, and in 2007, survivors were re-assessed with questionnaires.

RESULTS

Nonfrail as referent and adjusted for age, BMI and smoking, both prefrail (HR 2.26; 95% CI, 1.57-3.26), and frail status (4.09; 95% CI, 2.60-6.44) were significant predictors of mortality. Nonfrailty predicted better survival independently of the frailty components, diseases, and disability, and also predicted faster walking speed and less disability 7 years later.

CONCLUSIONS

Frailty, and also prefrailty, as defined using questionnaire data (RAND-36) independently predicted important endpoints in older men.

The role of serum non-cholesterol sterols as surrogate markers of absolute cholesterol synthesis and absorption

AIMS

To study the whole-body cholesterol metabolism in man, cholesterol synthesis and absorption need to be measured. Because of the complicated methods of the measurements, new approaches were developed including the analysis of serum non-cholesterol sterols. In current lipidologic papers and even in intervention studies, serum non-cholesterol sterols are frequently used as surrogate markers of cholesterol metabolism without any validation to the absolute metabolic variables. The present review compares serum non-cholesterol sterols with absolute measurements of cholesterol synthesis and absorption in published papers to find out whether the serum markers are valid indicators of cholesterol metabolism in various conditions.

DATA SYNTHESIS

During statin treatment, during interventions of dietary fat, and in type 2 diabetes the relative and absolute variables of cholesterol synthesis and absorption were frequently but not constantly correlated with each other. In some occasions, especially in subjects with apolipoprotein E3/4 and E4/4 phenotypes, the relative metabolic markers were even more sensitive than the absolute ones to reflect changes in cholesterol metabolism during dietary interventions. Even in general population at very high absorption the homeostasis of cholesterol metabolism is disturbed damaging the validity of the serum markers.

CONCLUSIONS

It is worth using several instead of only one precursor and absorption sterol marker for making conclusions of altered synthesis or absorption of cholesterol, and even then the presence of at least some absolute measurement is valuable. During consumption of plant sterol-enriched diets and in situations of interfered cholesterol homeostasis the relative markers do not adequately reflect cholesterol metabolism. Accordingly, the validity of the relative markers of cholesterol metabolism should not be considered as self-evident.

Serum and lipoprotein sitostanol and non-cholesterol sterols after an acute dose of plant stanol ester on its long-term consumption

PURPOSE

Chronic inhibition of cholesterol absorption with large doses of plant stanol esters (staest) alters profoundly cholesterol metabolism, but it is unknown how an acute inhibition with a large staest dose alters the postprandial serum and lipoprotein cholesterol precursor, plant sterol, and sitostanol contents.

METHODS

Hypercholesterolemic subjects, randomly and double-blind divided into control (n = 18) and intervention groups (n = 20), consumed experimental diet without and with staest (plant stanols 8.8 g/day) for 10 weeks. Next morning after a fasting blood sample (0 h), the subjects had a breakfast without or with staest (4.5 g of plant stanols). Blood sampling was repeated 4 h later. Lipoproteins were separated with ultracentrifugation, and sterols were measured with gas-liquid chromatography.

RESULTS

In 0-h chylomicrons and VLDL, plant sterols were lower in staest than in controls. Postprandially, cholestenol (cholesterol synthesis marker) was reduced in chylomicrons in staest compared with controls (-0.13 ± 0.04 μg/dL vs. 0.01 ± 0.08 μg/dL, P < 0.05). Staest decreased postprandially avenasterol in chylomicrons (P < 0.05 from 0 h). Sitostanol was high at 0 h by chronic staest in serum and VLDL but not in chylomicrons. Postprandial sitostanol was increased by staest in VLDL only.

CONCLUSIONS

Chronic cholesterol absorption inhibition with large amount of plant stanol esters decreases plant sterols in triglyceride-rich lipoproteins. Acute plant stanol ester consumption increases sitostanol content in triglyceride-rich lipoproteins but suggests to decrease the risk of plant sterol and plant stanol accumulation into vascular wall by chylomicrons.

Non-cholesterol sterols in serum and endarterectomized carotid arteries after a short-term plant stanol and sterol ester challenge

BACKGROUND AND AIMS

It is not known whether dietary intake of plant stanols or sterols changes the composition of arterial sterols. Therefore, we compared serum and carotid artery cholesterol and non-cholesterol sterols after plant stanol (staest) or sterol (steest) ester feeding in endarterectomized patients.

METHODS AND RESULTS

Elderly statin-treated asymptomatic patients undergoing carotid endarterectomy were randomized double-blind to consume staest (n=11) or steest (n=11) spread (2 g of stanol or sterol/day) for four weeks preoperatively. Non-cholesterol sterols from serum and carotid artery tissue were analysed with gas-liquid chromatography. Staest spread lowered serum total (17.2%), VLDL, and LDL cholesterol and serum triglycerides, while steest spread lowered serum total (13.8%) and LDL cholesterol levels from baseline (p<0.05 for all). Serum cholestanol and avenasterol were decreased in both groups, but campesterol and sitosterol were decreased by staest and increased by steest from baseline (p<0.05 from baseline and between the groups). Serum sitostanol to cholesterol ratio was increased by staest, but in arterial tissue this ratio was similar in both groups. On staest, lathosterol, campesterol, and sitosterol, and on steest sitosterol and avenasterol correlated significantly between serum and arterial tissue. Cholesterol metabolism, eg. lathosterol/campesterol, suggested that plant sterols were reduced in serum and in arterial tissue during staest.

CONCLUSION

The novel observations were that plant stanol ester consumption, in contrast to plant sterols, tended to reduce carotid artery plant sterols in statin-treated patients. Furthermore, despite increased serum sitostanol contents during plant stanol ester consumption, their arterial levels were unchanged suggesting that sitostanol is not taken up into the arterial wall.

Cholesterol, non-cholesterol sterols and bile acids in paediatric gallstones

BACKGROUND

Depending on underlying aetiopathogenetic factors human gallstones contain various amounts of cholesterol, non-cholesterol sterols and bile acids, which have remained unexplored in paediatric gallstone patients.

AIMS

To evaluate sterol and bile acids compositions of paediatric gallstones.

PATIENTS AND METHODS

Study group included 21 consecutively cholecystectomised children. Gas-liquid chromatography was used to quantitate gallstone sterols and bile acids. Results were compared to adult gallstones (n=194).

RESULTS

Cholesterol stones (n=9) had higher proportions of cholesterol and lathosterol, but lower those of lanosterol and phytosterols than pigment stones (n=12) (p<0.05 for each). Patients with gallstone cholesterol content over 70% were female. Gallstone cholesterol positively reflected body mass index and, in cholesterol stones-group, age (r=approximately +0.700, p<0.05). Three patients on parenteral nutrition had brown pigment stones consisting of high amounts of campesterol and sitosterol ranging 483-9303 microg/100 mg of stone. Pigment stones had 13-fold higher amount of bile acids than cholesterol stones (p<0.05). Black pigment stones contained approximately 3-fold higher phytosterol proportions, and pigment stones and cholesterol stones had approximately 43% lower proportions of deoxycholic acid than adults (p<0.05).

CONCLUSION

Gallstones in patients on parenteral nutrition are rich in phytosterols. With respect to gallstone sterols, gallstone disease of adolescent girls resembles that of adults. Composition of bile acids in paediatric gallstones is different from adults.

Twenty-one year tracking of serum non-cholesterol sterols. The Cardiovascular Risk in Young Finns study

BACKGROUND AND AIM

To show tracking of cholesterol metabolism, the ratios to cholesterol of e.g. serum cholestenol, desmosterol, and lathosterol, reflecting cholesterol synthesis, and cholestanol, campesterol, avenasterol and sitosterol, reflecting cholesterol absorption, were measured 21 years apart.

METHODS AND RESULTS

In random population samples initially comprising 12- (n=162), 15- (n=158), and 18-year-old (n=148) males participating in the Cardiovascular Risk in Young Finns Study, serum sterols and squalene were measured with gas-liquid chromatography in 1980 and 2001. Quartiles of cholestanol, indicating low to high cholesterol absorption, were defined from the cholestanol values in 1980. Serum cholesterol increased in the oldest age group only, but synthesis markers (except desmosterol) increased in all age groups after the follow-up (e.g. lathosterol, total population +47.3+/-2.6% (SE), P<0.001). Campesterol (+69.0+/-3.0%, P<0.001) and sitosterol increased, avenasterol was unchanged, and cholestanol decreased (-6.2+/-0.7%, P<0.001), respectively. The 1980 synthesis and absorption markers were interrelated with respective values 21 years later in all age groups and quartiles (e.g. lathosterol, total population 1980 vs. 2001 r=0.460, cholestanol 1980 vs. 2001 r=0.593, P<0.001 for both). Synthesis markers were highest in the first and lowest in the fourth quartile both in 1980 and 2001 (e.g. 2001, desmosterol, quartile 1, 99+/-9, quartile 4, 83+/-2 microg/mg of cholesterol, P<0.05).

CONCLUSIONS

Cholesterol metabolism is significantly tracked in adolescent males over the follow-up of 21 years. Thus, high cholesterol synthesis and low absorption characterize subjects with the lowest cholestanol quartile, while those with the highest quartile have low synthesis and high absorption in both adolescence and later in young adult life.

A Bartter-like syndrome after jejunoileal bypass for obesity

A case of an adult woman with a Bartter-like syndrome after jejunoileal bypass for obesity is described. Diarrhoea, hypokalaemia, high plasma renin activity, hyperaldosteronism, alkalosis, increased urinary prostaglandin E and hyperplasia of the juxtaglomerular apparatus with low or normal blood pressure were the major features. After corrective surgery the values turned only transiently towards normal, despite permanent disappearance of the diarrhoea. Spironolactone, amiloride or propranolol had no real effect on clinical symptoms or biochemical aberrations. Indomethacin, a prostaglandin synthetase inhibitor, normalized most of the aberrations, but--inexplicably--not the prostaglandinuria.

Chocolate, well-being and health among elderly men

OBJECTIVE

We hypothesized that chocolate preference would be related to health and psychological well-being in old men.

DESIGN, SETTING AND PARTICIPANTS

We have followed up a socio-economically homogenous group of men, born in 1919-1934, since the 1960s. In 2002-2003, a mailed questionnaire was used to assess the health and well-being (including questions related to positive life orientation, visual analogue scales and the Zung depression score) of survivors. In addition, candy preference was inquired. Those men who reported no candy consumption (n=108) were excluded from the analyses.

OUTCOME MEASURES

Psychological well-being in old age.

RESULTS

The response rate was 69% (1367 of 1991). Of the respondents, 860 and 399 preferred chocolate and other type of candy, respectively. The average age in both candy groups was 76 years. Of the respondents, 99% were home-dwelling, 96% were retired and 87% were presently married, without differences between the candy groups. Men preferring chocolate had lower body mass index and waist circumference, and they also reported more exercise and better subjective health (P=0.008) than other candy consumers. Variables related to psychological well-being were consistently better in those preferring chocolate. The differences were statistically significant in feeling of loneliness (P=0.01), feeling of happiness (P=0.01), having plans for the future (P=0.0002) and the Zung depression score (P=0.02).

CONCLUSIONS

In this socioeconomically homogenous male cohort, chocolate preference in old age was associated with better health, optimism and better psychological well-being.

SPONSORSHIP

The Academy of Finland, the Päivikki and Sakari Sohlberg Foundation, the Helsinki University Central Hospital and the Finnish Foundation for Cardiovascular Research.

Postprandial behavior of plasma squalene and non-cholesterol sterols in men with varying cholesterol absorption

BACKGROUND

The purpose of this study was to investigate, whether low vs. high absorption of cholesterol affects the postprandial lipid clearance (squalene as the surrogate marker) and postprandial cholesterol metabolism evaluated with plasma levels of cholesterol absorption (cholestanol and plant sterols) and synthesis markers (desmosterol and lathosterol).

METHODS

Fifteen normo- or mildly hypercholesterolemic men were divided into low or high cholesterol absorbers on the basis of plasma cholestanol to cholesterol ratio and they volunteered to an oral fat load test containing fat 35 g/m(2) body surface.

RESULTS

Plasma squalene to cholesterol ratio did not differ between the groups throughout the postprandial follow-up of 8 h. The level differences in the plasma absorption and synthesis markers seen at baseline remained between the groups, so that in high absorbers the absorption markers remained high and synthesis markers low throughout the postprandial follow-up. The postprandial response curves of desmosterol (p<0.05) and lathosterol (p=0.052) to cholestanol decreased linearly in the low, but not in the high absorbers.

CONCLUSIONS

Low vs. high absorption of cholesterol does not affect the first 8-h postprandial lipid clearance. The metabolic profile of cholesterol is maintained postprandially. The postprandial decrease in cholesterol synthesis differs in low vs. high absorbers especially through the desmosterol pathway.

Ester percentages of plant sterols and cholesterol in chylomicrons and VLDL of humans with low and high sterol absorption

Ester percentages of cholesterol and non-cholesterol sterols were measured in chylomicrons and very low density lipoproteins (VLDL) in 15 subjects. Our hypothesis was that in humans, in contrast to animal experiments, plant sterols in chylomicrons are esterified similarly to cholesterol. In fact, the mean ester percentage of chylomicron sitosterol (approximately 40%), but not of campesterol ( approximately 51%), was lower than that of cholesterol (approximately 54%) in the whole study population. In high cholesterol absorbers (high serum total campesterol, > or = 2.8 mmol/mol of cholesterol), the ester percentages of sitosterol and other non-cholesterol sterols were similar to that of cholesterol in chylomicrons, and the percentages tended to be higher than those in low absorbers. In contrast to chylomicrons, the ester percentages of sterols in VLDL tended to be lower in the high than low absorbers. In conclusion, percentages of plant sterol esters are not consistently lower than those of cholesterol in chylomicrons.

Plant stanol and sterol esters in prevention of cardiovascular diseases: a review

Plant sterol and stanol esters have been introduced as an additional dietary means to lower serum total and LDL cholesterol concentration. In short-term studies they lower LDL cholesterol by 10%, and according to a meta-analysis by Malcolm Law the incidence of coronary heart disease is considered to be reduced by over 20% in long-term use of these products. Plant stanol and sterol esters are not identical sterols; they have different metabolic effects and their long-term efficacy seems to be different. The present review deals with the differences of the sterols and discusses what is known of their role in preventing the cardiovascular diseases.

Synthesis and absorption markers of cholesterol in serum and lipoproteins during a large dose of statin treatment

BACKGROUND

Serum contains noncholesterol sterols, which are reliable markers of cholesterol metabolism, but their presence and importance in different lipoproteins have been insufficiently studied.

MATERIALS AND METHODS

Serum and lipoprotein cholesterol precursors squalene, cholestanol, desmosterol and lathosterol (markers of cholesterol synthesis) and cholestanol and plant sterols (markers of cholesterol absorption), and absorption efficacy and absolute synthesis of cholesterol were studied at baseline and during 6-month atorvastatin (80 mg day(-1)) treatment by the sterol balance technique in men with type 2 diabetes.

RESULTS

At baseline, approximately 14% of serum squalene was transported by VLDL, 12% by IDL, 40% by LDL and 30% by HDL. The respective values for the noncholesterol sterols were approximately 8, 4, 61 and 26%. The squalene to cholesterol ratios were highest in VLDL and IDL, those of cholestanol, desmosterol and absorption marker sterols were gradually higher, and that of lathosterol lower from VLDL to HDL. Atorvastatin reduced LDL cholesterol by approximately 50%, decreased the absolute cholesterol synthesis and turnover by approximately 40%, but increased significantly the fractional and mass absorption of cholesterol. In accordance with the fecal data, the ratios of the precursor sterols to cholesterol were reduced (-50%), but those of squalene (+48%) and the absorption sterols increased (e.g. 2.6-fold for sitosterol) similarly in each lipoprotein, but progressively from VLDL to HDL.

CONCLUSIONS

Effective lowering of LDL cholesterol by large dose of statin is associated with decreased synthesis and turnover of cholesterol and increased fractional and mass absorption of cholesterol. These changes are detectable by noncholesterol sterols in serum and in different lipoprotein fractions.

Impact of midlife weight change on mortality and quality of life in old age. Prospective cohort study

OBJECTIVE

To examine the effects of weight change during midlife on long-term mortality risk and quality of life in old age.

DESIGN

Prospective cohort study with a 26-y follow-up.

SUBJECTS

Socioeconomically homogeneous sample of 1657 men (born 1919-1934) who had attended health checks during the 1960s, were healthy and professionally active in 1974, and could recall their weight at the age of 25 y.

MAIN OUTCOME MEASURES

Total mortality 1974-2000, scales of the RAND-36 (SF-36) health survey in 91% (n=1147) of the survivors in 2000.

RESULTS

Body weight increased from 25 y of age until midlife, but not thereafter. During the 26-y follow-up, 392 men (23.7% of the initial 1974 cohort) died. Weight at 25 y of age did not predict death, but the adjusted mortality risk was significantly increased in the highest quartile of midlife weight gain (>/=15.0 kg) compared with lower quartiles (RR 1.39, 95% CI 1.12-1.73). In 2000, multivariate analyses (adjusted for body weight at the age of 25 y and in 2000, age, smoking, alcohol and subjective health and physical fitness in 1974) showed impairment in all eight RAND-36 scales (statistically significantly in seven) with increasing weight gain in midlife.

CONCLUSION

In this homogeneous male cohort, only the largest weight gain from 25 y of age to midlife predicted long-term mortality. Weight gain sensitively affected later health-related quality of life, and zero weight gain up to midlife was associated with the best quality of life in old age.

Effects of gender, apolipoprotein E phenotype and cholesterol-lowering by plant stanol esters in children: the STRIP study. Special Turku Coronary Risk Factor Intervention Project

AIM

To evaluate the effects of gender, apolipoprotein E phenotype and cholesterol absorption and synthesis (estimated as serum plant sterol and cholesterol precursor sterol concentrations) on the cholesterol-lowering effect of plant stanol esters in children.

METHODS

Eighty-one healthy, normocholesterolaemic 6-y-old children (45 boys) were recruited from the Special Turku Coronary Risk Factor Intervention Project (STRIP), a randomized prospective trial aiming at atherosclerosis prevention in childhood. This placebo-controlled, double-blind, cross-over study comprised two 3-mo study periods and a 6-wk wash-out period. During the study periods, 20 g of the children's daily dietary fat intake was replaced with plant stanol ester margarine or control margarine.

RESULTS

In boys, plant stanol esters reduced serum total and low-density lipoprotein cholesterol concentrations by 6% (0.09 to 0.42 mmol/L) and 9% (0.09 to 0.36 mmol/L), respectively (p < 0.01 for both). In girls, the decreases in concentrations were 4% (0.03 to 0.38 mmol/L) and 6% (0.02 to 0.32 mmol/l) (p < 0.05 for both). The response rate did not differ between the genders. Serum total and low-density lipoprotein cholesterol concentrations decreased by 6% and 8% (p < 0.01 for both), respectively, in both children with the apolipoprotein E 3/4 or 4/4 (apoE4+) phenotype and the apolipoprotein E 2/3 or 3/3 (apoE4-) phenotype. Cholesterol absorption decreased both in the apoE4+ children and in the apoE4- children, but cholesterol synthesis consistently increased in the apoE4+ children only.

CONCLUSION

Plant stanol esters reduce serum cholesterol concentration in healthy children irrespective of their gender or apoE4 phenotype.

LDL cholesterol lowering by bile acid malabsorption during inhibited synthesis and absorption of cholesterol in hypercholesterolemic coronary subjects

BACKGROUND AND AIMS

Recent large-scale trials have consistently documented the fact that a 25-35% reduction in low-density lipoprotein cholesterol (LDL-C) can delay the progression of atherosclerosis. This raises the question as to how much it is possible to reduce serum cholesterol using feasible therapies. The aim of this study was to investigate the cholesterol-lowering efficacy of a triple therapy combining bile acid malabsorption with the inhibition of cholesterol synthesis and absorption.

METHODS AND RESULTS

Eleven consecutive hypercholesterolemic coronary patients from Lipid Clinics on a low-fat, low-cholesterol baseline diet added simvastatin (20 mg/day) for three months, and then dietary plant stanol ester margarine (2.25 g of stanols/day) for eight weeks; finally, cholestyramine 8 g/day was added for another eight weeks. This was a before-after trial, in which the results of each period were compared with baseline and those of the previous period. Serum lipids were quantitated using commercial kits, and serum sterols by means of gas-liquid chromatography. Simvastatin lowered LDL-C by 39% (p < 0.001), and additional stanol ester margarine by a further 13% (p < 0.05). The triple treatment led to 67% reduction from baseline (p < 0.001), with all LDL-C values being < 2.6 mmol/L, and increased high-density lipoprotein cholesterol (HDL-C) by 15% (p < 0.01). It also increased the serum lathosterol/cholesterol ratio (p < 0.01), thus indicating an upregulation of cholesterol synthesis, and increased the serum sitosterol ratio (p < 0.01) despite the simultaneous consumption of plant stanols.

CONCLUSIONS

The massive reduction in LDL and increase in HDL-C obtained using our triple therapy suggests that the combination of stanol ester with only moderate doses of statin and resin makes it possible to control LDL-C levels effectively in hypercholesterolemic subjects.

Baseline intestinal absorption and synthesis of cholesterol regulate its response to hypolipidaemic treatments in coronary patients

Baseline cholesterol metabolism was hypothesized to regulate responses of cholesterol synthesis and absorption, and serum cholesterol lowering to hypolipidaemic treatment. Thus, serum cholesterol and non-cholesterol sterols were measured before and during long-term simvastatin treatment (inhibition of cholesterol synthesis) and subsequent combination of statin with plant stanol ester margarine (inhibition of cholesterol absorption) consumption in subjects with low (n=15) and high (n=15) absorption of cholesterol, defined by respective low and high baseline ratios of serum cholestanol to cholesterol. Cholesterol synthesis (defined by precursors of cholesterol) was markedly reduced by the long-term statin treatment in both groups, but more extensively in the low than high absorption group (P<0.05), yet the respective serum cholesterol reductions were similar. From among the absorption markers, sitosterol and cholestanol ratios were correspondingly increased more in the low than in the high absorption group. Plant stanol ester margarine consumption, combined with chronic statin treatment, further lowered the serum cholesterol level (P<0.001) only in the high absorption group. The sum of cholesterol absorption markers was reduced more (P<0.05) in the high than in the low absorption group, while the non-significant serum cholesterol reduction of the low absorption group was associated with relatively high increase of cholesterol synthesis. Thus, stanol ester margarine combined with chronic simvastatin treatment reduces cholesterol absorption and serum cholesterol more consistently in subjects with high than low baseline absorption of cholesterol. The profile of baseline cholesterol metabolism determines the changes in synthesis and absorption of cholesterol to hypolipidaemic treatments, but affects less differently serum cholesterol level.

Apolipoprotein E phenotype regulates cholesterol absorption in healthy 13-month-old children--The STRIP Study

High serum cholesterol concentration is one of the key risk factors in development of atherosclerosis, which may begin early in life and later progress to symptomatic coronary heart disease. In adults, apoE polymorphism strongly influences cholesterol metabolism, as subjects with apoE 3/4 or 4/4 (collectively called apoE4) phenotype absorb cholesterol effectively and thus also have higher cholesterol absorption-reflecting plant sterol concentrations in serum than subjects with other apoE phenotypes. Because of the inverse correlation of absorption and synthesis of cholesterol, concentrations of cholesterol synthesis-reflecting serum cholesterol precursor sterols are lower in subjects with apoE4 than in subjects with other phenotypes. To analyze whether apoE phenotype affects cholesterol absorption and synthesis in early childhood, we measured serum plant sterol (campesterol and sitosterol) and cholesterol precursor sterol (desmosterol and lathosterol) concentrations in healthy 13-month old children using gas-liquid chromatography. The 36 study children were participants in a randomized prospective trial (the Special Turku Coronary Risk Factor Intervention Project) aimed at decreasing exposure of the children to environmental atherosclerosis risk factors. The 16 apoE4 children had 30% to 50% higher cholesterol-adjusted campesterol and sitosterol concentrations in serum than the 20 apoE 3/3 children (p = 0.002 and p = 0.02, respectively). The concentrations of cholesterol precursor sterols in serum did not differ between the two groups of children. We conclude that the young apoE4 children may absorb cholesterol and plant sterols more effectively than the children with apoE 3/3 phenotype without compensatory reduction in endogenous synthesis of cholesterol.

Cholesterol absorption inhibition: a strategy for cholesterol-lowering therapy

A clear relationship has been documented between plasma levels of low-density lipoprotein cholesterol (LDL-C) and the risk of coronary heart disease. LDL-C is believed to be key in the pathogenesis of coronary atherosclerosis, although increasing evidence suggests that low levels of high-density lipoprotein cholesterol and elevated triglyceride levels are contributory factors. Chylomicron remnants formed via the exogenous (dietary and biliary) pathway of cholesterol metabolism may also have atherogenic potential. Dietary modification, especially with plant stanol (sterol) ester margarine, which inhibits cholesterol absorption and improves the fatty acid pattern, lowers LDL-C sufficiently in many hypercholesterolaemic patients, and is also a useful adjunct to pharmacological therapy. Cholesterol absorption inhibitors typically lower LDL-C by 10-20%. Ezetimibe, the first selective cholesterol absorption inhibitor, has been shown to lower LDL-C by approximately 18% following a once-daily 10 mg dose, either as monotherapy or as combination therapy. Combination therapy with selective cholesterol absorption inhibitors such as ezetimibe along with statins or fibrates may allow more patients with hypercholesterolaemia to achieve target LDL-C levels compared with treatment with monotherapy. Ezetimibe may be useful in the management of patients who respond poorly to or are unable to tolerate statins, or in patients with hereditary or drug-induced phytosterolaemia.

Cholesterol absorption, synthesis, and fecal output in postmenopausal women with and without coronary artery disease

Hypercholesterolemia is a prominent risk factor for coronary artery disease (CAD), yet cholesterol metabolism has not been evaluated in women with CAD. The objective of this study was to determine the interrelations of CAD, serum squalene and sterols, and cholesterol metabolism with each other in postmenopausal women. For this purpose, we measured serum squalene and sterols and fecal steroids (cholesterol and bile acids) and squalene by gas-liquid chromatography and evaluated cholesterol absorption and synthesis in postmenopausal women with CAD (n=29) and age-matched controls (n=20). On similar dietary lipid intake, the cholesterol absorption efficiency and mean serum cholesterol level were comparable, but the squalene-to-cholesterol ratio was higher in cases than in controls. The presence of CAD was inversely associated with fecal total steroids (logistic regression coefficient beta/SE=-2.11, P=0.04) and cholesterol synthesis (beta/SE=-2.14, P=0.04) and turnover (beta/SE=-2.19, P=0.03) after adjustment for dietary cholesterol, family history of CAD, smoking, low and high density lipoprotein cholesterol, and serum triglyceride levels. A high serum squalene ratio was not related to cholesterol synthesis but was inversely related to fecal squalene excretion, which was lower in cases than in controls. In conclusion, the presence of CAD in postmenopausal women is independently associated with altered cholesterol metabolism, as reflected by low synthesis and inefficient elimination of cholesterol.

Dyslipidemia and a reversible decrease in insulin sensitivity induced by therapy with 13-cis-retinoic acid

BACKGROUND

13-cis-Retinoic acid (Roaccutan) treatment is associated with disturbances in lipid and sometimes also in glucose metabolism. Thus, we investigated whether 13-cis-retinoic acid treatment decreases insulin sensitivity.

METHODS

We studied 11 men [aged 24+/-2 years (mean+/-SEM), body mass index (BMI) 22.1+/-0.9 kg/m(2)] who received Roaccutan treatment for acne for a period averaging 5 months but who were otherwise healthy. The insulin sensitivity of the subjects was measured before, during and 1-3 months after the end of treatment using the euglycaemic hyperinsulinaemic clamp technique.

RESULTS

Treatment with 13-cis-retinoic acid reduced total (59+/-4 vs 55+/-4 micromol/kg/min, p<0.02), oxidative (25+/-1 vs 22+/-2 micromol/kg/min, p<0.05) and non-oxidative (36+/-3 vs 33+/-3 micromol/kg/min, p=0.05) glucose disposal rate, and there was a 4% increase in HbA(1c) (from 5.2+/-0.07 to 5.4+/-0.07%, p<0.02). After treatment cessation these values returned to baseline. 13-cis-Retinoic acid treatment also resulted in increased very low density lipoprotein (VLDL) and low density lipoprotein (LDL) cholesterol, increased VLDL triglyceride, and increased VLDL and LDL phospholipid concentrations.

CONCLUSION

Treatment of acne with 13-cis-retinoic acid reduces insulin sensitivity and induces alterations in lipid metabolism resembling those of the insulin resistance syndrome.

Familial hypercholesterolaemia in Finland: common, rare and mild mutations of the LDL receptor and their clinical consequences. Finnish FH-group

Familial hypercholesterolaemia (FH) is an autosomal co-dominantly inherited condition resulting from mutations of the low-density lipoprotein (LDL) receptor which occur in heterozygous form in approximately one in 500 individuals. Clinically, FH is characterized by 2-3-fold elevation of serum LDL cholesterol levels, accelerated development of atherosclerotic vascular disease, and, if untreated, shortened lifespan. The Finnish population, which represents a genetic isolate, offers exceptional possibilities for genetic-epidemiological studies on FH, as a handful of founder gene mutations account for the majority of FH cases in Finland. This review summarizes data from our FH studies carried out since 1985. We wish to emphasize the continuum of genotype-phenotype relationships, the importance of molecular diagnosis, the detection of novel risk factors of vascular disease, and innovations inhibiting cholesterol absorption for the modern treatment of FH.

Dietary plant sterols alter the serum plant sterol concentration but not the cholesterol precursor sterol concentrations in young children (the STRIP Study). Special Turku Coronary Risk Factor Intervention Project

Plant sterol supplementation reduces serum cholesterol concentration but may increase serum plant sterol concentrations, especially in children. We determined whether natural dietary plant sterols derived mainly from vegetable oil or margarine in early childhood affect serum concentrations of plant sterols (campesterol and sitosterol) and cholesterol precursor sterols (Delta-8 cholestenol, desmosterol, and lathosterol), reflecting endogenous cholesterol synthesis. We measured the serum sterol concentrations using gas liquid chromatography in 20 healthy 13-mo-old intervention children in a randomized, prospective study designed to decrease exposure of the children to known environmental atherosclerosis risk factors and in 20 control children. The diet of the intervention children was rich in plant sterols due to replacement of milk fat with vegetable fat, whereas the diet of the control children contained only small amounts of plant sterols. The intervention children consumed twice as much plant sterols as the control children (P < 0.001). Their serum concentrations of campesterol and sitosterol were 75% and 44% higher, respectively, than those in the control children (P < 0.001 for both), but serum cholesterol precursor sterol concentrations did not differ between the two groups. We conclude that doubling dietary plant sterol intake almost doubles serum plant sterol concentrations in 13-mo-old children, but has no effect on endogenous cholesterol synthesis. Relative intestinal absorption of natural plant sterols from the diet in early childhood is similar to that in adults.

Fate of intravenously administered squalene and plant sterols in human subjects

We have studied metabolism of plant sterols and squalene administered intravenously in the form of lipid emulsion mimicking chylomicrons (CM). The CM-like lipid emulsion was prepared by dissolving squalene in commercially available Intralipid. The emulsion was given as an intravenous bolus injection of 30 ml containing 6.3 mg of cholesterol, 1.9 mg of campesterol, 5.7 mg of sitosterol, 1.6 mg of stigmasterol, 18.1 mg of squalene, and 6 g of triglycerides in six healthy volunteers. Blood samples were drawn from the opposite arm before and serially 2.5 -180 min after the injections. The decay of CM squalene, plant sterols, and triglycerides was monoexponential. The half-life of CM squalene was 74 +/- 8 min, that of campesterol was 37 +/- 5 min (P < 0.01 from squalene), and those of sitosterol, stigmasterol, and triglycerides were 17 +/- 2, 15 +/- 1, and 17 +/- 2 min, respectively (P < 0.01 from squalene and campesterol). The CM squalene concentration still exceeded the baseline level 180 min after injection (P = 0.02), whereas plant sterols and triglycerides returned to the baseline level between 45 and 120 min after injection. The half-lives of squalene and campesterol were positively correlated with their fasting CM concentrations. In addition, VLDL squalene, campesterol, and triglyceride concentrations, VLDL, LDL, and HDL sitosterol concentrations, as well as VLDL and LDL stigmasterol concentrations were increased significantly. Cholesterol concentrations increased in VLDL (P < 0.05), but were unchanged in CM after injection. These data suggest that squalene clearance occurs more slowly than that of plant sterols and triglycerides from CM, and that squalene is more tightly associated with triglyceride-rich lipoproteins than are plant sterols in injected CM-like emulsions.

Acute effect of dietary stanyl ester dose on post-absorptive alpha-tocopherol, beta-carotene, retinol and retinyl palmitate concentrations

Stanyl esters dissolved in margarine inhibit cholesterol absorption, lower sterol absorption in general, and lower serum total cholesterol, LDL-cholesterol and plant sterol levels. To find out whether stanyl esters inhibit absorption of fat-soluble vitamins and beta-carotene in acute experiments, we performed two fat-tolerance tests fortified with vitamins (retinol 0.9-3.7 mg, alpha-tocopherol 70-581 mg), beta-carotene (25-150 mg) and squalene (0.5 g) with and without 1 g of stanyl ester added to the test meal in ten healthy men. The concentrations or areas under the curves (AUC) of cholesterol, triacylglycerols, squalene and alpha-tocopherol, beta-carotene and retinyl palmitate showed typical postprandial changes in serum, chylomicrons, VLDL and VLDL infranatant (intermediate-density lipoproteins, LDL and HDL) over 24 h after the test meal without stanyl esters, and they were not affected by the addition of stanyl esters. The post-absorptive serum campesterol concentration and campesterol : cholesterol were significantly lowered at 6-9 h by stanyl ester supplementation, reflecting reduced sterol absorption efficiency. Changes in vitamin and beta-carotene AUC did not correlate with the given doses. In conclusion, the present study shows that stanyl esters dissolved in margarine do not detectably interfere in a short-term study with the absorption of alpha-tocopherol, beta-carotene or retinol measured by a 24 h oral fat-load test.

Smith-Lemli-Opitz syndrome and other sterol disorders among Finns with developmental disabilities

Smith-Lemli-Opitz syndrome (SLOS) is an inherited disorder of cholesterol metabolism in which 7- and 8-dehydrocholesterols are accumulated in blood and tissues. Diagnosis of SLOS and other disorders in cholesterol metabolism (eg, cerebrotendinous xanthomatosis, phytosterolemia, desmosterolosis, and X-linked dominant Conradi-Hünermann-Happle syndrome) can be performed by gas-liquid chromatographic analysis of serum sterols. To elucidate their involvement in developmental disability, we evaluated serum sterols in two study groups: developmentally disabled subjects in long-term care (N = 322) and newborns and young children (N = 49) with features of SLOS in the Finnish population of 5 million. Only 1 SLOS case (type II) was found from among the 49 children. Seven additional adult cases (type I) with a wide range of clinical features and the serum sterol abnormalities characteristic of SLOS were detected from among the developmentally disabled subjects. The frequency of SLOS in the latter group was relatively high (7 in 322). No other hereditary sterol disorders were found, but two subgroups with low serum cholesterol precursor sterols and high serum plant sterols were identified. Several subjects, including the 7 SLOS patients, used ample medication and had abnormalities in serum sterol concentrations. Thus, among the subjects taking melperone, a high serum delta8-cholestenol level suggests an interference by the drug with cholesterol synthesis. Our results emphasize the importance of analyzing the serum sterols of developmentally disabled subjects to diagnose SLOS and of finding putative undiagnosed disorders in sterol metabolism associated with these clinical conditions.

Cholesterol absorption efficiency and sterol metabolism in obesity

Role of enterohepatic cholesterol metabolism in obesity-induced increase of cholesterol synthesis was studied in healthy lean (BMI <24) and overweight (BMI >31) subjects by measuring serum lipids (including plant sterols, cholestanol and cholesterol precursors), cholesterol absorption % (double-label method), sterol balance and biliary lipids. New aspects of sterol metabolism in obesity were as follows: low efficiency of cholesterol absorption, reduced ratios to cholesterol of serum and biliary plant sterols and cholestanol (5alpha-derivative of cholesterol), and a marked increase of serum and biliary cholesterol precursor sterols. Percent of cholesterol absorption was positively related to serum cholestanol and plant sterols, and negatively to cholesterol synthesis, measured by the sterol balance technique or cholesterol precursor sterols in serum or bile. Total and endogenous cholesterol fluxes into the intestine were increased, but owing to low absorption percent, mass of cholesterol absorption was within control limits in the obese subjects. Thus, per gram of their large liver tissue the entry of intestinal cholesterol may even be subnormal. Percent of cholesterol absorption was insignificantly negatively (r=-0.256) related to intestinal cholesterol pool, but significantly to biliary concentrations of cholesterol (r=-0.581), bile acids (r=-0.513) and phospholipids (r=-0.469). Thus, dilution of labeled dietary cholesterol by expanded intestinal cholesterol pool could have contributed to subnormal efficiency of cholesterol absorption, or transfer of labeled dietary cholesterol from intestinal oil phase to micellar phase may be competitively inhibited by expanded biliary secretion, resulting in reduced absorption of dietary cholesterol. These mechanisms could have contributed to changes in metabolism of non-cholesterol sterols, especially of cholestanol and plant sterols.

Postprandial retinyl palmitate and squalene metabolism is age dependent

Most of our awake time is spent in a postprandial state. It has not been investigated in detail whether the post-prandial clearance of triglyceride-rich lipoproteins is age dependent. In addition, postabsorptive squalene metabolism has not been studied in relation to age. Accordingly, we investigated postprandial lipid metabolism in six young (22-25 years of age) and eight old (78-79 years of age) healthy men by use of an oral fat load containing 345,000 IU of vitamin A and 0.5 g of squalene as postprandial markers. Postprandial samples were drawn after 3, 4, 6, 9, 12 and 24 hours after the fat load. The retinyl palmitate area under the incremental curve of the old subjects was higher in plasma than that of the young subjects (p < .01). The pattern of postprandial very low density lipoprotein squalene responses differed significantly in the old compared with the young subjects (p < .01), but the areas under the incremental curve did not differ. Postprandial retinyl palmitate and squalene concentrations correlated significantly at 3-12 hours (p < .01). These data suggest that postprandial lipoprotein metabolism measured by retinyl palmitate and squalene is retarded with increasing age.

Dietary squalene increases cholesterol synthesis measured with serum non-cholesterol sterols after a single oral dose in humans

Studies considering long-term squalene consumption have revealed no consistent effects on serum cholesterol levels but the immediate effect of dietary squalene on cholesterol synthesis has not been studied. Thus, the effect of a single dose of dietary squalene on postprandial lipid metabolism was studied in 16 male volunteeers aged 22-79 years. Two oral fat meals a week apart were administered to every subject, one without (control) and the other with 500 mg of squalene. Lipids, retinyl palmitate, squalene and non-cholesterol sterols were measured at baseline and after 3, 4, 6, 9, 12 and 24 h postprandially in plasma, chylomicron, VLDL and VLDL bottom and, in six randomly chosen subjects, also in IDL, LDL and HDL. In the fasting samples, squalene was mainly transported in LDL and HDL, whereas in squalene-supplemented postprandium most of squalene was carried in the triglyceride-rich lipoproteins. Postprandial squalene and retinyl palmitate curves closely resembled each other. After the squalene-enriched dietary fat load, squalene was significantly increased compared to control fat loads in plasma, chylomicrons, VLDL and IDL. Squalene addition increased significantly lathosterol/campesterol ratio in chylomicrons and VLDL at 12 h and in VLDL bottom at 9-12 h, and increased significantly VLDL lanosterol/campesterol ratio at 12 h, indicating enhanced cholesterol synthesis caused by squalene. Plasma plant sterol levels remained unchanged. In conclusion, a single oral dose of squalene representing a potential daily dietary amount increases cholesterol synthesis within 9-12 h detected in chylomicrons, VLDL and VLDL bottom.

Rye bread improves bowel function and decreases the concentrations of some compounds that are putative colon cancer risk markers in middle-aged women and men

Cereal fiber may reduce the risk of colorectal cancer by diluting colonic contents due to increased fecal output, by accelerating intestinal transit, by increasing fecal frequency and by altering bacterial metabolism. The effects of whole-meal rye bread on some putative colon cancer risk markers were investigated in 17 healthy Finnish subjects using a randomized crossover trial with two 4-wk bread consumption periods and a 4-wk washout period between the bread periods. White wheat bread was used as a control. Test breads covered a minimum of 20% of the daily energy intake (range, 4330-14, 033 kJ/d). Intestinal transit time, stool weight, fecal bacterial enzyme activities and short-chain fatty acid, ammonia, diacylglycerol (DAG) and bile acid concentrations in feces (expressed per gram wet feces) were measured. Whole-meal rye bread significantly increased fecal output and fecal frequency and shortened mean intestinal transit time compared with wheat bread in both women and men. Activities of beta-glucuronidase and beta-glucosidase (expressed per gram wet feces) were significantly lower in men and urease activity significantly higher in women during the rye bread period (RBP). Fecal butyrate concentration was higher during the RBP in men. Fecal ammonia and DAG concentrations did not differ between bread periods. Fecal total and secondary bile acid concentrations were significantly lower during RBP in both women and men. This study shows that whole-meal rye bread significantly improves bowel function in healthy adults and may decrease the concentration of some compounds that are putative colon cancer risk markers.

Cure of Helicobacter pylori infection after failed primary treatment: one-center results from 120 patients

BACKGROUND

Treatment with a proton pump inhibitor (PPI) and antimicrobials cures Helicobacter pylori infection in about 90% of patients. This is a retrospective overview of our studies aiming to cure the infection in all compliant patients with failed initial therapy.

METHODS

We retreated 120 (19% of 644) H. pylori-infected patients whose initial therapy had failed. The retreatments included (i) triple therapy (TT): colloidal bismuth subcitrate, metronidazole, amoxicillin (or tetracycline); (ii) quadruple therapy (QT): TT and a PPI; or (iii) high doses of both a PPI and clarithromycin combined with a further 1-3 individually selected antimicrobials. The eradication results were determined after 6-12 months.

RESULTS

The 1st retreatment was successful in 70 of 120 patients. The 2nd retreatment cured 25 of the remaining 42 patients, the 3rd 13 of 17, and the 4th the last 4 patients. The cumulative eradication rate (ITT) was 93% (95% CI: 88.9%-97.9%; 8 patients withdrew after a failed 1st retreatment) and the rate was 100% in the remaining 112 patients who accepted several retreatments. The 1st retreatment with TT cured 23% (95% CI: 12%-34%) of 57 patients and QT 85% (95% CI: 74%-96%) of 41 patients who had initially undergone a failed metronidazole-based treatment. All retreatments were well tolerated.

CONCLUSIONS

In this study, high doses of a PPI and clarithromycin combined with 1-3 antimicrobials according to susceptibility data proved to be the best drug combination in the cure of H. pylori infection after failed primary treatment. Giving imidazole- and bismuth-based QT (without clarithromycin) as the first-line treatment of H. pylori infection ensures that the number of failures remains low.

Statin treatment increases the sialic acid content of LDL in hypercholesterolemic patients

Low density lipoprotein (LDL) with low sialic acid content has been reported to cause intracellular cholesterol accumulation, and therefore desialylation has been proposed to be an atherogenic modification of LDL. However, it is not known whether hypolipidemic treatment has any effect on LDL sialylation. Accordingly, we investigated the sialic acid/apolipoprotein (apo) B ratio of total LDL and its subfractions in 26 moderately hypercholesterolemic patients at baseline and after treatment with statins for 2-3 months. Cholesterol and triglyceride levels were reduced in all apo B-containing lipoproteins, including all LDL subfractions, while the sialic acid ratio was increased in total LDL and in all its subfractions. Cholesterol concentrations and sialic acid ratios were inversely correlated in light and dense LDL subfractions both before and during statin treatment, and the greater the decrease in cholesterol and apo B contents of dense LDL, the higher was the increase in its sialic acid ratio. Furthermore, the lower the baseline sialic acid ratio of dense LDL, the greater was the reduction in its lipid and apo B concentrations. In conclusion, inhibition of cholesterol synthesis by statin treatment increased sialic acid/apo B ratio in LDL proportionately to the decrease of LDL apo B and cholesterol.

Sialic acid content of low-density lipoprotein in women with coronary artery disease

A low sialic acid content in low-density lipoprotein (LDL) has been associated with coronary artery disease (CAD) in studies that have included mostly male subjects. We compared the sialic acid-to-apolipoprotein B ratios of total LDL and its subfractions in middle-aged women with CAD (CAD+, n = 22) with those ratios in healthy female control subjects (CAD-, n = 11). CAD+ subjects had a lower sialic acid ratio in total LDL and in its subfractions as compared with results in CAD- subjects. In total, light, and dense LDL, the sialic acid ratio was negatively correlated with the respective cholesterol and phospholipid concentrations, and in very dense LDL, it was negatively correlated with triglyceride concentration. In multivariate analysis, CAD and LDL cholesterol contributed to the explanation of the variability of LDL sialic acid ratios. In summary, a low sialic acid-to-apolipoprotein B ratio in LDL was associated with the presence of CAD in middle-aged women with mild to moderate hypercholesterolemia.

Sialic acid content of low density lipoprotein and its relation to lipid concentrations and metabolism of low density lipoprotein and cholesterol

A low sialic acid content in low density lipoprotein (LDL) has been associated with atherogenicity and coronary artery disease (CAD) in many but not all studies. We investigated associations of the sialic acid-to-apolipoprotein B (apoB) ratio of LDL with lipoprotein lipid concentrations, kinetics of LDL, metabolism of cholesterol, and the presence of CAD in 98 subjects (CAD(+), n = 56; CAD(-), n = 42). The sialic acid ratios of total, dense, and very dense LDL were lower in the CAD(+) than CAD(-) subjects, especially at high sialic acid ratios. The LDL sialic acid ratio was inversely associated with respective lipid and apoB concentrations and positively with lipid-to-apoB ratios of LDL. The transport rates (TRs) for total and dense LDL apoB were negatively associated with their sialic acid ratios. The sialic acid ratio of dense LDL, but not that of total LDL, was inversely correlated with serum levels of cholesterol precursor sterols, indicators of cholesterol synthesis, and positively with serum levels of plant sterols, indicators of cholesterol absorption. In addition, the TR for dense LDL was positively correlated with cholesterol synthesis. In conclusion, a low LDL sialic acid ratio was associated with CAD, high numbers of small LDL particles, and a high TR for LDL apoB, and in dense LDL also with high synthesis and low absorption of cholesterol.

Introducing a new component of the metabolic syndrome: low cholesterol absorption

BACKGROUND

Weight reduction is the recommended treatment of obese type 2 diabetes, but the effects of weight reduction on cholesterol metabolism are poorly understood.

OBJECTIVE

We investigated glucose, cholesterol, and lipoprotein metabolism at baseline and 2 y after weight reduction in obese patients with type 2 diabetes consuming an isoenergetic diet.

DESIGN

Sixteen subjects were randomly chosen to consume a very-low-energy or low-energy diet for 3 mo, after which they consumed a weight-maintenance diet for up to 2 y. Cholesterol absorption and metabolism, LDL and HDL kinetics, and variables of glucose metabolism were studied at baseline and 2 y.

RESULTS

Baseline serum sex hormone binding globulin (SHBG) was significantly related to cholesterol absorption efficiency, and serum glucose and insulin concentrations were associated with cholesterol synthesis. After 2 y, body weight was reduced by 6 +/- 1 kg (P < 0.01), body mass index by 6% (P < 0.05), and blood glucose by 14% (P < 0.01); the ratio of serum SHBG to insulin increased by 66% (P < 0.05). Serum and VLDL, LDL, and HDL triacylglycerol were significantly reduced by 13-24%. Despite unchanged serum concentrations of cholesterol, cholesterol absorption efficiency and the ratio of serum plant sterols to cholesterol-indicators of cholesterol absorption-increased by 28% (P < 0.01) and 20-31% (P < 0. 05 for both), respectively; the fractional removal of LDL apolipoprotein B decreased. Fecal excretion of cholesterol as neutral sterols decreased significantly by 11%. Changes in body weight were significantly negatively correlated with changes in ratios of cholesterol to serum plant sterols and cholestanol.

CONCLUSIONS

Baseline cholesterol absorption and synthesis were related to respective serum SHBG, glucose, and insulin values. Weight reduction increased cholesterol absorption and improved variables of glucose metabolism. These results suggest that low cholesterol absorption and high synthesis may be part of the insulin resistance syndrome.

Does increased crypt cell proliferation impair cholesterol absorption after proximal gut resection?

BACKGROUND

The effects of proximal small-bowel resection on absorption and synthesis of cholesterol are unclear.

METHODS

To study cholesterol absorption and synthesis after proximal gut resections of variable length, plasma plant sterols, cholestanol, and cholesterol precursors were measured 1 and 2 months after 50% and 75% proximal small-bowel resection or transection. To examine the effect of increased crypt cell proliferation and brush border development on cholesterol absorption, the results were related to the mucosal morphology, crypt cell proliferation, and disaccharidase activities of the remaining small bowel.

RESULTS

Campesterol levels in proportion to cholesterol decreased markedly more, and those of cholestanol markedly less, than would be expected simply due to the amount of proximal small intestine removed, whereas sitosterol proportions decreased in proportion to the length of gut resection. Campesterol proportions markedly (P = 0.06) increased between 1 and 2 months after 50% resection but remained unchanged after 75% resection. Crypt cell proliferation was only increased in the 75% resection group (P < 0.05). The longer the proximal gut resection, the lower was the mucosal enzyme activity. Both resection groups showed increased plasma cholesterol precursor proportions and crypt depth (P < 0.05), whereas villus height remained unchanged. After massive proximal resection campesterol and sitosterol proportions were inversely related to crypt cell proliferation (r = -0.86-0.83, P < 0.01).

CONCLUSIONS

Increased crypt cell proliferation activated by massive proximal gut resection may act as a previously unrecognized factor in aggravating cholesterol malabsorption and retarding its recovery during the early postoperative period. These findings warrant further investigation.

Noncholesterol sterols and cholesterol lowering by long-term simvastatin treatment in coronary patients: relation to basal serum cholestanol

Coronary patients with low baseline ratios of serum cholestanol and plant sterols to cholesterol (indicating low cholesterol absorption) but not those with high ratios (high absorption) experienced reduced recurrences of coronary events during simvastatin treatment in the Scandinavian Simvastatin Survival Study. Thus, in the present study, serum cholesterol, its precursor sterols (reflecting cholesterol synthesis), plant sterols (campesterol and sitosterol), and cholestanol were measured before and during a 5-year period of placebo treatment (n=433) and simvastatin treatment (n=434) in patients from a subgroup of the Scandinavian Simvastatin Survival Study to determine whether changes in cholesterol synthesis and serum levels were related to cholesterol absorption. Serum cholesterol level was unchanged, the ratios of cholesterol precursor sterols to cholesterol were decreased, and the ratios of plant sterols to cholesterol were increased in relation to increasing baseline ratios of cholestanol quartiles. The latter predicted 5-year ratios and simvastatin-induced reductions of the precursor sterols, with the lowering of the ratios (cholesterol synthesis reduction) being almost twice higher in the lowest versus the highest quartile. The ratios of plant sterols, especially campesterol, to cholesterol were markedly increased during simvastatin treatment, mostly in subjects with the highest baseline cholestanol quartiles. Simvastatin reduced serum cholesterol more (P=0.003) in the lowest versus the highest cholestanol quartile during the 5-year treatment period. The results show for the first time that baseline cholesterol metabolism, measured by serum noncholesterol sterols, predicts the effectiveness of simvastatin in reducing cholesterol synthesis and serum levels of cholesterol. The drug suppresses the synthesis of cholesterol markedly more effectively in subjects with high than with low baseline synthesis but reduces respective serum cholesterol levels less markedly than synthesis. Subjects with high cholesterol absorption and low synthesis may need a combination therapy to lower more effectively their serum cholesterol levels and prevent an increase in the levels of plant sterols.

Serum, biliary, and fecal cholesterol and plant sterols in colectomized patients before and during consumption of stanol ester margarine

BACKGROUND

Cholesterol metabolic studies are simplified in colectomized patients because of rapid intestinal passage and reduced bacterial action.

OBJECTIVE

Our objective was to study the effect on cholesterol and plant sterol metabolism of feeding a margarine containing stanol ester to 11 colectomized patients.

DESIGN

A margarine containing 2 g stanol was consumed for 7-18 d. Serum, biliary, and fecal lipids were measured before and during consumption of the margarine.

RESULTS

Serum cholesterol concentrations and the ratio of plant sterol to cholesterol decreased after 1 d of consumption of stanol esters (P < 0.05). After 7 d, serum cholesterol decreased by 16% (P < 0.01), cholesterol absorption efficiency decreased by approximately 40%, and fecal output of cholesterol as neutral sterols (but not as bile acids) increased by 36%. Biliary bile acid composition and the molar percentage of biliary cholesterol were unchanged. Increased ratios of cholesterol precursor sterols in serum and bile indicated enhanced cholesterol synthesis during consumption of stanol esters; the percentage absorption of plant sterols and the ratios of plant sterols to cholesterol decreased, whereas serum and biliary plant stanols and their biliary secretion gradually increased. In feces, 95% of cholesterol and 90% of plant stanols were in unesterified form.

CONCLUSIONS

In colectomized patients, effective inhibition of cholesterol absorption and lowering of serum cholesterol concentrations and plant sterol ratios occurs within 1 d of the start of consumption of stanol esters. The composition of major bile lipids is unchanged, indicating that gallstone formation is unlikely. Small amounts of plant stanols are recovered in serum and bile during consumption of stanol esters but effectively are secreted through bile, thereby balancing the intake-induced increase in their absorption.

Independent association of serum squalene and noncholesterol sterols with coronary artery disease in postmenopausal women

OBJECTIVES

The purpose of the study was to investigate whether cholesterol metabolism is associated with coronary artery disease (CAD) in postmenopausal women.

BACKGROUND

Although hypercholesterolemia, a predominant risk factor of CAD, is related to cholesterol metabolism, the association between cholesterol metabolism and CAD is not well known.

METHODS

In addition to conventional coronary risk factors, fasting serum squalene, delta8-cholestenol, desmosterol, lathosterol (indicators of cholesterol synthesis), cholestanol, campesterol and sitosterol (indicators of cholesterol absorption) were measured in 48 50- to 55-year-old consecutive women with angiographically verified CAD and in 61 age-matched healthy controls.

RESULTS

The coronary patients had elevated ratios of squalene (p < 0.001), desmosterol (p = 0.005), campesterol (p = 0.028) and sitosterol (p = 0.022) to cholesterol, but had lower respective lathosterol value (p = 0.041) compared with the controls, despite similar serum cholesterol levels. Adjusted for age, body mass index, family history of CAD, smoking, hypertension, serum triglycerides, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol level and glycosylated hemoglobin A1c% (GHbA1c), the ratios of squalene (odds ratio, 1.36; 95% confidence interval, 1.17 to 1.57), lathosterol (0.98; 0.97 to 0.99), campesterol (1.01; 1.00 to 1.01) and sitosterol (1.01; 1.00 to 1.03) were significantly associated with the risk of CAD. In addition, family history of CAD and GHbA1c% were also independently related to the presence of CAD.

CONCLUSIONS

The results suggest that women with elevated ratios of serum squalene, campesterol and sitosterol to cholesterol and low respective lathosterol values have enhanced risk for CAD. Thus, enhanced absorption and reduced synthesis of cholesterol may be related to coronary atherosclerosis.

Effect of stanol ester on postabsorptive squalene and retinyl palmitate

Stanol ester dissolved in margarine inhibits cholesterol absorption in general and, despite increasing cholesterol synthesis, decreases serum total and low-density lipoprotein (LDL) cholesterol levels, but its effects on postprandial lipid metabolism are unknown. We performed fat tolerance tests in 11 men at baseline and during short-term stanol ester consumption without and with stanol esters added to the test meal also containing retinol and squalene. Cholesterol, triglycerides, retinyl palmitate, and squalene were analyzed in plasma, chylomicrons, and very-low-density lipoprotein (VLDL) at baseline and 3, 4, 6, 9, 12, and 24 hours after the test meal. Serum total and LDL cholesterol only tended to diminish after the 2-week stanol ester consumption. However, the proportion of plasma plant sterol and cholesterol-precursor sterol to cholesterol was significantly altered, suggesting that cholesterol absorption was diminished and cholesterol synthesis was increased. Postprandial peak times of squalene and retinyl palmitate in plasma, chylomicrons, and VLDL were significantly reduced by stanol esters, but their concentrations in chylomicrons were unchanged. Stanol esters reduced the VLDL squalene peak concentration by 23% (P < .05) and the incremental area under the curve (AUIC) in plasma and VLDL by 22% and 32% (P < .01 for both). Chylomicron remnant metabolism measured with triglycerides only tended to diminish. The effects of stanol esters in the diet only and both in the diet and with supplementation did not differ significantly. We conclude that dietary stanol esters reduce postprandial lipoproteins measured with dietary retinyl palmitate and especially squalene, and the reduction is observed even though serum total and LDL cholesterol are only inconsistently decreased after short-term stanol ester consumption.

Oral guar gum, a gel-forming dietary fiber relieves pruritus in intrahepatic cholestasis of pregnancy

BACKGROUND

Guar gum is a gel-forming fiber, which increases fecal elimination of bile acids. It may therefore be beneficial in the treatment of intrahepatic cholestasis of pregnancy.

METHODS

Forty-eight patients with intrahepatic cholestasis of pregnancy were randomized double-blind to receive either guar gum or placebo until delivery. Serum bile acid concentration was measured. Pruritus was assessed by both the investigator and the patient.

RESULTS

At baseline, the intensity of pruritus and the serum bile acid concentration were significantly related. Guar gum diminished or prevented worsening of pruritus, while in the placebo group pruritus was enhanced (p<0.05). In the placebo group serum bile acid concentration increased significantly, whereas in the guar gum group it remained unchanged (p<0.05 between the groups). Guar gum treatment-induced changes of the pruritus score and serum bile acid concentrations were significantly related (p<0.01).

CONCLUSIONS

Guar gum relieved the intensity of pruritus without any side effects and prevented the rise in serum bile acid concentration in this placebo-controlled and double-blind study of patients with intrahepatic cholestasis of pregnancy.