Beneficial effects of weight loss on plasma apolipoproteins in postmenopausal women

Effect of behavioral weight-loss program on biomarkers of cardiometabolic disease risk: Heart Health Study randomized trial

OBJECTIVE

This study aimed to determine whether novel biomarkers of cardiometabolic health improve in response to a 12-month behavioral weight-loss intervention and to compare benefits of diet alone with diet plus physical activity for these biomarkers.

METHODS

Participants (N = 374) were randomized to either diet alone (DIET), diet plus 150 min/wk of prescribed moderate-intensity physical activity (DIET + PA150), or diet plus 250 min/wk of prescribed moderate-intensity physical activity (DIET + PA250). Biomarker concentrations were determined using nuclear magnetic resonance spectroscopy. Mixed models assessed for a time effect, group effect, or group by time interaction.

RESULTS

All groups significantly improved body weight (time: p < 0.0001), Lipoprotein Insulin Resistance Index score (time: p < 0.0001), Diabetes Risk Index score (time: p < 0.0001), branched-chain amino acid concentration (time: p < 0.0001), and GlycA concentration (time: p < 0.0001), with no group effect or group by time interactions.

CONCLUSIONS

All intervention groups prompted a notable beneficial change among biomarkers of insulin resistance and cardiometabolic health. However, the addition of at least moderate-intensity physical activity to a diet-only intervention did not provide any additional benefit. These findings highlight that an average weight loss of approximately 10% profoundly impacts biomarkers of insulin resistance and cardiometabolic disease in adults with overweight or obesity.

The effects of Elaeagnus angustifolia L. on lipid and glycaemic profiles and cardiovascular function in menopausal women: A double-blind, randomized, placebo-controlled study

AIMS

The reduced production of ovarian hormones is considered to be the cause of an increase in the incidence of heart disease in women after menopause. Phytoestrogens are found in various herbal sources and are considered as an alternative to hormone therapy because of structural similarity with oestrogen. Elaeagnus angustifolia L., known as Senjed in Persian, is used in Iranian traditional medicine with various medicinal properties, contains valuable compounds, including two types of phytoestrogens. The aim of the present study was to investigate the efficacy of E. angustifolia fruit on the cardiovascular function, lipid and glycaemic profiles in postmenopausal women.

METHODS

In this double-blind placebo-controlled clinical trial, 58 postmenopausal women were randomly assigned into two experimental groups of medicinal herb (15 g/day of the whole E. angustifolia fruit powder) and placebo (15 g/day of isomalt + corn starch). Before the trial and after 10 weeks of the treatment, cardiovascular function (heart rate, blood pressure), serum glycaemic profile (fasting blood glucose; glycated haemoglobin, HbA1C), insulin and lipid profile (total cholesterol, TC; triglyceride, TG; LDL-C and HDL-C) were measured.

RESULTS

Heart rate, and serum level of LDL-C and HDL-C significantly decreased after treatment with E. angustifolia. Changes in glycaemic profile were not clinically significant. In addition, some studied biochemical parameters significantly changed in the placebo group.

CONCLUSIONS

E. angustifolia was somewhat effective in improving cardiovascular function and lipid profile, as well as the overall health of postmenopausal women. However, the use of isomalt and corn starch in menopausal women needs further investigation.

Apoprotein C-III: A review of its clinical implications

Apoprotein C-III (apoC-III), originating from the apoA-I/C-III/A-IV gene cluster affected by multiple regulating factors, has been demonstrated to have a validated link with hypertriglyceridemia in humans. Following genome studies establishing the impact of apoC-III on both plasma triglyceride (TG) level and cardiovascular disease (CVD), apoC-III offers us a novel explanation attempting to resolve the long-existing confusion with regard to the atherogenic effect of TG. Notably, apoC-III exerts its atherogenic effect by means of not only intervening in the function and metabolism of various lipid molecules, but also accelerating pro-inflammatory effects between monocytes and endothelial cells. Data have suggested that diabetes, a common endocrine disease, also correlates closely with apoC-III in its apoptosis process of islet βcells. In fact, apoC-III genes, with various mutations among individuals, are also found to have relevance to other diseases, including fatty liver disease. Fortunately, besides present day therapeutic strategies, such as lifestyle changes and lipid-lowering drug treatments, a promising new antisense drug specifically targeting on apoC-III gene expression opens up new avenues. This article mainly summarizes the clinical implication of apoC-III and its future directions of treatment.

Effects of soya isoflavones and exercise on body composition and clinical risk factors of cardiovascular diseases in overweight postmenopausal women: a 6-month double-blind controlled trial

Results from a pilot project indicate that isoflavones and exercise could have an additive effect on body composition and clinical risk factors of CVD in postmenopausal women. The objective of the present study was to assess the combined effect of exercise and isoflavones in overweight-to-obese postmenopausal women. In this double-blind randomised controlled trial, 100 overweight-to-obese (BMI 29·9 (sd 3·2) kg/m2) postmenopausal women were assigned to four groups: (1) placebo (PLA); (2) isoflavones (ISO); (3) exercise and placebo (Ex+PLA); (4) exercise and isoflavones (Ex+ISO). The supplementation contained 70 mg/d of isoflavones. Exercise consisted of three weekly sessions of resistance training and aerobics. Outcome measures included fat mass (FM), lean body mass (LBM), bone mineral density, lipid profile, fasting glucose, fasting insulin and insulin resistance (homeostasis assessment model). The main effects of exercise were observed for total FM (P = 0·02), FM% (P < 0·01), trunk FM% (P = 0·05), arm FM% (P < 0·01), leg FM% (P = 0·02), arm LBM (P < 0·01), leg LBM (P = 0·02) and C-reactive protein (P < 0·01). A main effect was detected for isoflavones in improving leg FM% (P = 0·05). No interactions were observed between isoflavones and exercise. In conclusion, it was observed that 6 months of exercise brought favourable changes in total FM, FM% and LBM in overweight postmenopausal women. No synergistic effects were observed between exercise and isoflavones. However, isoflavones could have a beneficial effect on leg FM%.

The effects of ezetimibe and/or orlistat on triglyceride-rich lipoprotein metabolism in obese hypercholesterolemic patients

We investigated the factors influencing triglycerides (TG) reduction during ezetimibe, alone or combined with orlistat, administration. Eighty-six obese hypercholesterolemic subjects were prescribed a low-fat diet and were randomized to ezetimibe (E group), orlistat (O group), or both (OE group) for 6 months. Plasma TG and apolipoprotein (apo) C-III reduction was significantly greater in the combination group compared with monotherapy. Multivariate analysis showed that in E group apoC-III reduction and baseline TG levels were independently positively correlated, whereas baseline apoC-II levels were negatively correlated, with TG lowering. In OE group apoC-III reduction was the only independent contributor to TG reduction.

American College of Sports Medicine Position Stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults

Overweight and obesity affects more than 66% of the adult population and is associated with a variety of chronic diseases. Weight reduction reduces health risks associated with chronic diseases and is therefore encouraged by major health agencies. Guidelines of the National Heart, Lung, and Blood Institute (NHLBI) encourage a 10% reduction in weight, although considerable literature indicates reduction in health risk with 3% to 5% reduction in weight. Physical activity (PA) is recommended as a component of weight management for prevention of weight gain, for weight loss, and for prevention of weight regain after weight loss. In 2001, the American College of Sports Medicine (ACSM) published a Position Stand that recommended a minimum of 150 min wk(-1) of moderate-intensity PA for overweight and obese adults to improve health; however, 200-300 min wk(-1) was recommended for long-term weight loss. More recent evidence has supported this recommendation and has indicated more PA may be necessary to prevent weight regain after weight loss. To this end, we have reexamined the evidence from 1999 to determine whether there is a level at which PA is effective for prevention of weight gain, for weight loss, and prevention of weight regain. Evidence supports moderate-intensity PA between 150 and 250 min wk(-1) to be effective to prevent weight gain. Moderate-intensity PA between 150 and 250 min wk(-1) will provide only modest weight loss. Greater amounts of PA (>250 min wk(-1)) have been associated with clinically significant weight loss. Moderate-intensity PA between 150 and 250 min wk(-1) will improve weight loss in studies that use moderate diet restriction but not severe diet restriction. Cross-sectional and prospective studies indicate that after weight loss, weight maintenance is improved with PA >250 min wk(-1). However, no evidence from well-designed randomized controlled trials exists to judge the effectiveness of PA for prevention of weight regain after weight loss. Resistance training does not enhance weight loss but may increase fat-free mass and increase loss of fat mass and is associated with reductions in health risk. Existing evidence indicates that endurance PA or resistance training without weight loss improves health risk. There is inadequate evidence to determine whether PA prevents or attenuates detrimental changes in chronic disease risk during weight gain.

Effect of weight loss on markers of triglyceride-rich lipoprotein metabolism in the metabolic syndrome

BACKGROUND

Hypertriglyceridaemia, a consistent feature of dyslipidaemia in the metabolic syndrome (MetS), is related to the extent of abdominal fat mass and altered adipocytokine secretion. We determined the effect of weight loss by dietary restriction on markers of triglyceride-rich lipoprotein (TRL) metabolism and plasma adipocytokines.

DESIGN

Thirty-five men with MetS participated in a 16 week randomized controlled dietary intervention study. Apolipoprotein (apo) C-III, apoB-48, remnant-like particle (RLP)-cholesterol, total adiponectin, high-molecular weight (HMW) adiponectin, and retinol-binding protein-4 (RBP-4) concentrations were measured using immunoassays.

RESULTS

Compared with weight maintenance (n = 15), weight loss (n = 20) significantly decreased body weight, plasma insulin, triglycerides, total cholesterol, low-density lipoprotein (LDL)-cholesterol and lathosterol (P < 0.05). Weight loss also decreased plasma concentrations of apoC-III (-33%), apoB-48 (-37%), very low-density lipoprotein (VLDL)-apoB (-43%), RLP-cholesterol (-48%), and RBP-4 (-20%), and significantly increased plasma total (+20%) and HMW-adiponectin (+19%) concentrations. In the weight loss group, reduction in plasma apoC-III was associated (P < 0.05) with reduction in plasma apoB-48, VLDL-apoB, RLP-cholesterol and triglycerides. Increase in total adiponectin was associated (P < 0.05) with the reduction in plasma VLDL-apoB and triglycerides. The changes in HMW-adiponectin and RBP-4 were not associated with changes in plasma apoB-48, apoC-III, VLDL-apoB, RLP-cholesterol or triglycerides. In multiple regression analysis including changes in visceral fat, insulin and total adiponectin concentrations, the fall in plasma apoC-III concentration was an independent predictor of the reductions in plasma apoB-48, VLDL-apoB, RLP-cholesterol and triglycerides concentrations.

CONCLUSIONS

In men with MetS, weight loss decreases the plasma concentrations of apoB-48, VLDL-apoB, RLP-cholesterol and triglycerides. This effect could partly relate to concomitant changes in plasma apoC-III and adiponectin concentrations that accelerate the catabolism of TRLs.

Analysis of 6-month effect of orlistat administration, alone or in combination with fenofibrate, on triglyceride-rich lipoprotein metabolism in overweight and obese patients with metabolic syndrome

BACKGROUND

Orlistat significantly reduced serum triglycerides (TG) in most clinical trials. Orlistat-induced TG reduction has not been studied to determine the factors contributing to TG alterations in clinical settings.

OBJECTIVE

We examined the factors influencing TG reduction during orlistat administration, alone or in combination with fenofibrate, and we investigated the effects of these treatments on apolipoprotein C-II (ApoC-II) and C-III (ApoC-III) levels.

METHODS

Patients with the metabolic syndrome were randomly allocated to receive orlistat 120 mg three times daily (n = 28, O group), micronized fenofibrate 200 mg/day (n = 28, F group), or both (n = 27, OF group) for 6 months. Plasma ApoC-II and ApoC-III were determined by an immunoturbidimetric assay.

RESULTS

In the O group, we observed reductions of plasma ApoC-III (P < 0.05) and ApoC-II (P = NS) levels. Fenofibrate administration significantly reduced concentrations of ApoC-II and ApoC-III, whereas the combination of orlistat and fenofibrate had an additive effect on these apolipoproteins. There were significant in-group reductions in serum TG levels in all treatment groups. Multivariate analysis showed that in O group's baseline TG levels were independently positively correlated, whereas the baseline ApoC-II levels were negatively correlated with TG-lowering. In the F group, baseline TG levels and ApoC-III reduction were significantly and independently correlated with TG reduction. OF group's baseline TG levels and ApoC-III reduction were independently positively correlated and baseline ApoC-II levels were negatively correlated with TG-lowering.

CONCLUSIONS

Orlistat-mediated TG-lowering is independently associated with baseline TG and ApoC-II levels. When orlistat is combined with fenofibrate, ApoC-III reduction is another independent contributor to TG alterations.

Apolipoprotein C-III: understanding an emerging cardiovascular risk factor

The concurrence of visceral obesity, insulin resistance and dyslipidaemia comprises the concept of the metabolic syndrome. The metabolic syndrome is an escalating problem in developed and developing societies that tracks with the obesity epidemic. Dyslipidaemia in the metabolic syndrome is potently atherogenic and, hence, is a major risk factor for CVD (cardiovascular disease) in these subjects. It is globally characterized by hypertriglyceridaemia, near normal LDL (low-density lipoprotein)-cholesterol and low plasma HDL (high-density lipoprotein)-cholesterol. ApoC-III (apolipoprotein C-III), an important regulator of lipoprotein metabolism, is strongly associated with hypertriglyceridaemia and the progression of CVD. ApoC-III impairs the lipolysis of TRLs [triacylglycerol (triglyceride)-rich lipoproteins] by inhibiting lipoprotein lipase and the hepatic uptake of TRLs by remnant receptors. In the circulation, apoC-III is associated with TRLs and HDL, and freely exchanges among these lipoprotein particle systems. However, to fully understand the complex physiology and pathophysiology requires the application of tracer methodology and mathematical modelling. In addition, experimental evidence shows that apoC-III may also have a direct role in atherosclerosis. In the metabolic syndrome, increased apoC-III concentration, resulting from hepatic overproduction of VLDL (very-LDL) apoC-III, is strongly associated with delayed catabolism of triacylglycerols and TRLs. Several therapies pertinent to the metabolic syndrome, such as PPAR (peroxisome-proliferator-activated receptor) agonists and statins, can regulate apoC-III transport in the metabolic syndrome. Regulating apoC-III metabolism may be an important new therapeutic approach to managing dyslipidaemia and CVD risk in the metabolic syndrome.

An ABC of apolipoprotein C-III: a clinically useful new cardiovascular risk factor?

BACKGROUND

Hypertriglyceridaemia, commonly found in subjects with obesity and type 2 diabetes mellitus, is associated with increased risk of coronary heart disease (CHD). Apolipoprotein C-III (apoC-III) plays an important role in regulating the metabolism of triglyceride-rich lipoproteins (TRLs) and may provide a new approach to assessing hypertriglyceridaemia.

AIMS

We review the role of apoC-III in regulating TRL metabolism and address the potential importance of apoC-III in clinical practice.

DISCUSSION

Hypertriglyceridaemia is chiefly a consequence of alterations in the kinetics of TRLs, including overproduction and delayed clearance of very-low density lipoprotein (VLDL). ApoC-III is an inhibitor of lipoprotein lipase and of TRLs remnant uptake by hepatic lipoprotein receptors. Elevated apoC-III, usually resulting from hepatic overproduction of VLDL apoC-III, may cause accumulation of plasma TRLs leading to hypertriglyceridaemia. The results from recent observational studies demonstrate that apoC-III is a strong predictor of risk for CHD, but this chiefly relates to apoC-III in apoB-containing lipoproteins. Lifestyle and pharmacological intervention can correct hypertriglyceridaemia by a mechanism of action that regulates apoC-III transport.

CONCLUSIONS

Targeting apoC-III metabolism may therefore be an important, new therapeutic approach to managing dyslipidaemia and CHD risk in obesity, insulin resistance and type 2 diabetes mellitus. However, further work is required to establish the practical aspects of measuring apoC-III in routine laboratory service and the precise therapeutic targets for serum total apoC-III and/or apoC-III in apoB-containing lipoproteins. While showing much promise as a potentially useful cardiovascular risk factor, apoC-III is not yet ready for prime time use in clinical practice.

Dietary cholesterol from eggs increases plasma HDL cholesterol in overweight men consuming a carbohydrate-restricted diet

Carbohydrate-restricted diets (CRD) significantly decrease body weight and independently improve plasma triglycerides (TG) and HDL cholesterol (HDL-C). Increasing intake of dietary cholesterol from eggs in the context of a low-fat diet maintains the LDL cholesterol (LDL-C)/HDL-C for both hyper- and hypo-responders to dietary cholesterol. In this study, 28 overweight/obese male subjects (BMI = 25-37 kg/m2) aged 40-70 y were recruited to evaluate the contribution of dietary cholesterol from eggs in a CRD. Subjects were counseled to consume a CRD (10-15% energy from carbohydrate) and they were randomly allocated to the EGG group [intake of 3 eggs per day (640 mg/d additional dietary cholesterol)] or SUB group [equivalent amount of egg substitute (0 dietary cholesterol) per day]. Energy intake decreased in both groups from 10,243 +/- 4040 to 7968 +/- 2401 kJ (P < 0.05) compared with baseline. All subjects irrespective of their assigned group had reduced body weight and waist circumference (P < 0.0001). Similarly, the plasma TG concentration was reduced from 1.34 +/- 0.66 to 0.83 +/- 0.30 mmol/L after 12 wk (P < 0.001) in all subjects. The plasma LDL-C concentration, as well as the LDL-C:HDL-C ratio, did not change during the intervention. In contrast, plasma HDL-C concentration increased in the EGG group from 1.23 +/- 0.39 to 1.47 +/- 0.38 mmol/L (P < 0.01), whereas HDL-C did not change in the SUB group. Plasma glucose concentrations in fasting subjects did not change. Eighteen subjects were classified as having the metabolic syndrome (MetS) at the beginning of the study, whereas 3 subjects had that classification at the end. These results suggest that including eggs in a CRD results in increased HDL-C while decreasing the risk factors associated with MetS.

Changes in blood lipid levels following silastic ring vertical gastroplasty

BACKGROUND

The purpose of this study was to evaluate the effect of the Silastic Ring Vertical Gastroplasty (SRVG) operation on blood lipid levels in obese men and women during the first year following surgery.

METHODS

25 patients (11 men and 14 women) age 17-50 (mean 33 years) who suffered from morbid obesity (BMI >40, range 45.9+/-4.7 kg/m2) underwent SRVG. Blood samples were collected before operation and 3, 6 and 12 months following surgery and tested for: triglycerides, total cholesterol, HDL-C, LDL-C, VLDL-C, and Lp(a).

RESULTS

Both men and women lost weight significantly. Mean BMI decreased from 48.0 to 32.5 kg/m2 in men and from 44.3 to 29.0 kg/m2 in women (P<0.01). Blood lipid levels 1 year following surgery demonstrated the following changes: In women, triglycerides, total cholesterol, LDL, VLDL cholesterol and Lp(a) decreased from 160.7 mg/dL to 67.7 mg/dL (P<0.01), from 220 mg/dL to 189 mg/dL, from 138.3 mg/dL to 111 mg/dL, from 17 mg/dL to 12 mg/dL, and from 77.5 mg/dL to 18.5 mg/dL (P<0.01), respectively, and HDL increased from 45 mg/dL to 50.5 mg/dL. In men, triglycerides, total cholesterol, LDL, VLDL cholesterol and Lp(a) decreased from 246 mg/dL to 140 mg/dL (P<0.01), from 206 mg/dL to 170 mg/dL (P<0.01), from 134 mg/dL to 112 mg/dL (P<0.05), from 25 mg/dL to 15 mg/dL (P<0.01), and from 30.3 mg/dL to 11.6 mg/dL (P<0.01), respectively, and HDL increased from 31.3 mg/dL to 37.4 mg/dL (P<0.05).

CONCLUSION

SRVG improved blood lipid profile in obese patients during the first year following surgery. Reduction in cholesterol and its fractions reaches statistical significance only in men.

Increase in serum resistin during weight loss in overweight subjects is related to lipid metabolism

OBJECTIVE

Human resistin has been stated to influence preadipocyte cell numbers and to stimulate adipocyte triglyceride lipolysis in vivo and in vitro. However, its role in human obesity remains unclear.

DESIGN

Cross-sectional study for comparisons of lean and obese subjects, and subsequent longitudinal 4-month weight loss intervention study in obese subjects.

SUBJECTS

Healthy subjects, lean (n=20, BMI<25) and overweight (n=43, BMI>or=25).

MEASUREMENTS

Serum resistin, body weight, body fat, waist-to-hip ratio, as well as markers of insulin resistance and lipid metabolism at baseline and after 4 months of intervention.

RESULTS

Serum resistin was positively correlated to HOMA-IR (partial r=0.288; P=0.055), serum fructosamines (partial r=0.280; P=0.062), serum NEFA (partial r=0.276; P=0.066) and negatively to age (partial r=-0.349; P=0.019) and serum apolipoprotein A-1 (partial r=-0.363; P=0.014). During the intervention, serum resistin increased significantly (P<0.001). The increase was inversely related to changes in waist-to-hip ratio (P=0.025) and positively to serum apolipoprotein B (P=0.011). In males only, the increase in resistin during weight loss was predicted by total serum cholesterol at baseline (r=0.703, P=0.007). No relation was observed between changes in resistin and changes in HOMA-IR.

CONCLUSION

The present study indicates an association between serum resistin and markers of abdominal fat distribution as well as the regulation of lipid metabolism. However, human resistin is unlikely to play an independent role in the regulation of glucose metabolism.