Apolipoprotein(B) identifies dyslipidemic phenotypes associated with cardiovascular risk in normocholesterolemic type 2 diabetic patients

Increasing the complexity of lipoprotein characterization for cardiovascular risk in type 2 diabetes

The burden of cardiovascular disease is particularly high among individuals with diabetes, even when LDL cholesterol is normal or within the therapeutic target. Despite this, cholesterol accumulates in their arteries, in part, due to persistent atherogenic dyslipidaemia characterized by elevated triglycerides, remnant cholesterol, smaller LDL particles and reduced HDL cholesterol. The causal link between dyslipidaemia and atherosclerosis in T2DM is complex, and our contention is that a deeper understanding of lipoprotein composition and functionality, the vehicle that delivers cholesterol to the artery, will provide insight for improving our understanding of the hidden cardiovascular risk of diabetes. This narrative review covers three levels of complexity in lipoprotein characterization: 1-the information provided by routine clinical biochemistry, 2-advanced nuclear magnetic resonance (NMR)-based lipoprotein profiling and 3-the identification of minor components or physical properties of lipoproteins that can help explain arterial accumulation in individuals with normal LDLc levels, which is typically the case in individuals with T2DM. This document highlights the importance of incorporating these three layers of lipoprotein-related information into population-based studies on ASCVD in T2DM. Such an attempt should inevitably run in parallel with biotechnological solutions that allow large-scale determination of these sets of methodologically diverse parameters.

Use of Apolipoprotein B in the Era of Precision Medicine: Time for a Paradigm Change?

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of death worldwide and the risk of a major cardiovascular event is highest among those with established disease. Ongoing management of these patients relies on the accurate assessment of their response to any prescribed therapy, and their residual risk, in order to optimize treatment. Recent international guidelines and position statements concur that the plasma concentration of apolipoprotein B (apoB) is the most accurate measure of lipoprotein associated ASCVD risk. This is especially true for the growing number of individuals with diabetes, obesity, or the metabolic syndrome, and those on statin therapy. Most guidelines, however, continue to promote LDL-C as the primary risk marker due to uncertainty as to whether the greater accuracy of apoB is sufficient to warrant a paradigm shift. Recommendations regarding apoB measurement vary, and the information provided on how to interpret apoB results is sometimes insufficient, particularly for non-lipid specialists. Misinformation regarding the reliability of the assays is also frequently repeated despite its equivalent or better standardization than many other diagnostic assays. Thus, demand for apoB testing is relatively low, which means there is little incentive to increase its availability or reduce its cost. In this review, we examine the results of recent clinical outcomes studies and meta-analyses on the relative values of apoB, LDL-C, and non-HDL-C as markers of ASCVD risk. Although there is seemingly minimal difference among these markers when only population-based metrics are considered, it is evident from our analysis that, from a personalized or precision medicine standpoint, many individuals would benefit, at a negligible total cost, if apoB measurement were better integrated into the diagnosis and treatment of ASCVD.

Evaluation of risk factors in the development of type 2 diabetes in a Mexican population

Type 2 diabetes (T2D), which causes many adverse effects such as endothelial dysfunction and cardiovascular disease, affects approximately 425 million people worldwide. However, about half have not yet been diagnosed. For what is recommended the use of screening tools to identify individuals at risk for T2D or in the early stages of the disease in order to impement preventive strategies or early treatment. According to a widely used survey, the FINDRISC scale, a hereditary family history of T2D (FH-T2D) is as important a risk factor as having had high glucose levels. The aim of the present study was to carry out non-probabilistic sampling in a Mexican population to evaluate key factors in the development of diabetes. The participants were divided into three groups: with and without FH-T2D and diagnosed with T2D. A comparison of the groups with and without FH-T2D revealed higher values in the former for body mass index (BMI: 24.5 vs 21.9 kg/m²), glycosylated hemoglobin [Hb1Ac: 5.775% (39 mmol/mol) vs 4.825% (29 mmol/mol)] and triglycerides (164.18 vs 68.12 mg/dL), and a lower value for the BH₄/BH₂ index (0.7846 vs 1.6117). These results indicate significant metabolic alterations and endothelial dysfunction for the FH-T2D group. This strongly suggests the need to screen individuals with a family history of inherited T2D based on their level of HbA1c, triglycerides and BH₄.

Effect of physician characteristics and knowledge on the quality of dyslipidemia management and LDL-C target goal achievement in China: Subgroup analysis of the Dyslipidemia International Study

Objective

This study aimed to investigate the effect of physicians’ characteristics and knowledge of LDL–C target goals on the quality of lipid management in China.

Methods

A total of 25 317 dyslipidemia patients who had taken lipid–lowering medication for >3 months were enrolled in our study. Patients’ demographic data, medical history, lipid profile, their physician’s specialty and professional title and their hospital level as well as their LDL–C goal opinions were recorded.

Results

Questionnaires were completed by 926 physicians with 6 different specialties and 4 professional statuses, in 3 different–level hospitals. Most (74.5%) of the physicians recognized the importance of considering LDL–C serum concentration for treating dyslipidemia, and set target LDL–C goals according to the 2007 Chinese guidelines for 83.4% of their patients. The LDL–C goal achievement rate was significantly higher for patients whose physicians’ knowledge of LDL–C target goals was consistent with guideline recommendations, compared with those whose physicians’ knowledge was inconsistent with the guidelines (60.4% vs 31.1%, P < 0.0001). Physicians working in tier 1 (odds ration (OR) = 2.95; 95% CI 2.37–3.67), (OR = 1.56; 95% CI 1.34–1.81) and tier 2 (OR = 2.53; 95% CI 2.22–2.88), (OR = 1.16; 95% CI 1.06–1.27) hospitals, specialized in neurology (OR = 1.13; 95% CI 0.93–1.36), (OR = 1.57; 95% CI 1.40–1.77), internal medicine (OR = 1.07; 95% CI 0.90–1.27), (OR = 1.58; 95% CI 1.39–1.80), endocrinology (OR = 1.02; 95% CI 0.87–1.21), (OR = 1.63; 95% CI 1.47–1.82) and being a resident vs attending physician (OR = 1.05; 95% CI 0.92–1.20), (OR = 1.00; 95% CI 1.00–1.19) were independent risk factors for low knowledge of LDL–C target goals and low LDL–C goal achievement.

Conclusion

Chinese physicians’ characteristics and knowledge of LDL–C target goals were associated with patients’ LDL–C goal achievement.

Elevation of small, dense low density lipoprotein cholesterol-a possible antecedent of atherogenic lipoprotein phenotype in type 2 diabetes patients in Jos, North-Central Nigeria

BACKGROUND

The global prevalence of type 2 diabetes is increasing. Dyslipidaemia is a known complication of diabetes mellitus manifesting frequently as cardiovascular diseases and stoke. Elevation of small, dense low density lipoprotein has been recognised as a component of the atherogenic lipoprotein phenotype associated with cardiovascular complications. We speculate that the elevation of this lipoprotein particle may be the antecedent of the atherogenic lipoprotein phenotype. This study therefore aims to determine the pattern of dyslipidaemia among diabetes mellitus patients in Jos, North-Central Nigeria.

METHODS

One hundred and seventy-six patients with type 2 diabetes and 154 age-matched controls were studied. The patients with diabetes were regular clinic attenders and had stable glycaemic control. None were on lipid-lowering therapy. Anthropometric indices, blood pressure, and lipids (including total cholesterol, high density lipoprotein cholesterol, and triglyceride) were measured by chemical methods using the Hitachi 902 analyzer. Low density lipoprotein cholesterol was calculated using the Friedewald's equation. Small, dense low density lipoprotein cholesterol, -sdLDL-C was measured using the precipitation method by Hirano et al. Means of the different groups were compared using EPI Info and a P-value of <0.05 was accepted as significant difference.

RESULTS

Total cholesterol, low density lipoprotein cholesterol, triglyceride and small, dense lipoprotein cholesterol were all significantly higher in diabetes patients than controls except high density lipoprotein cholesterol. The percentage of LDL-C as sdLDL-C among the diabetes versus control group was 45% ± 17.79 v 32.0% ± 15.93. Serum sdLDL-C concentration was determined to be 1.45 ± 0.64 among diabetes patients and 0.8 ± 0.54 among control subjects. 75% of diabetes patients had hypertension and were taking blood pressure lowering medications.

CONCLUSION

The classical atherogenic lipoprotein phenotype was not demonstrated among subjects with type 2 diabetes mellitus in this study, but the elevation of serum small dense low density lipoprotein cholesterol in patients with sustained hypertension suggests the establishment of atherogenic complications among our diabetes patients.

Lipid and liver abnormalities in haemoglobin A1c-defined prediabetes and type 2 diabetes

BACKGROUND AND AIMS

We aimed to investigate lipid abnormalities and liver steatosis in patients with HbA1c-defined prediabetes and type 2 diabetes compared to individuals with HbA1c-defined normoglycaemia.

METHODS AND RESULTS

Ninety-one subjects with prediabetes according to HbA1c, i.e. from 5.7 to 6.4% (39-46 mmol/mol), 50 newly diagnosed patients with HbA1c-defined type 2 diabetes (HbA1c ≥6.5% [≥48 mmol/mol]), and 67 controls with HbA1c lower than 5.7% (<39 mmol/mol), were studied. Fasting blood samples for lipid profiles, fatty liver index (FLI), bioimpedance analysis, ultrasound scan of the liver, and BARD (body mass index, aspartate aminotransferase/alanine aminotransferase ratio, diabetes) score for evaluation of liver fibrosis, were performed in all subjects. In comparison to controls, subjects with prediabetes were characterised by: lower apolipoprotein AI and HDL cholesterol levels, higher blood pressure, triglycerides levels and apolipoprotein B/apolipoprotein AI ratio, higher FLI, increased prevalence of and more severe hepatic steatosis, similar BARD score, and higher total body fat mass. In comparison to subjects with diabetes, subjects with prediabetes exhibited: similar blood pressure and apolipoprotein B/apolipoprotein AI ratio, similar FLI, reduced prevalence of and less severe hepatic steatosis, lower BARD score, increased percent fat and lower total body muscle mass. In comparison to controls, subjects with diabetes showed: lower apolipoprotein AI and HDL cholesterol levels, higher blood pressure and triglycerides levels, higher FLI, increased prevalence of and more severe hepatic steatosis, higher BARD score, and higher total body muscle mass. Moreover, HbA1c was correlated with BMI, HOMA-IR, triglycerides, HDL cholesterol, AST, and ALT.

CONCLUSIONS

Subjects with HbA1c-defined prediabetes and type 2 diabetes, respectively, are characterised by abnormalities in lipid profile and liver steatosis, thus exhibiting a severe risk profile for cardiovascular and liver diseases.

Establishing cut-off values for apolipoprotein B and non-HDL-C according to LDL-C values in a South European population

BACKGROUND

Low-density lipoprotein cholesterol (LDL-C) remains the primary target of therapy in most strategies of dyslipidaemia management focused on cardiovascular disease prevention. Different guidelines have identified specific LDL-C cut-off points as targets for therapeutic intervention. Many clinical situations characterised by dyslipidaemia and elevated triglycerides are common in our environment and in overall industrialised countries. Thus, lipid goals based only on LDL-C could misclassify an important percentage of subjects. The objective of the present study was to establish cut-off point values for apoB and non-HDL-C in relation to the identified LDL-C cut-off points for cardiovascular risk in a South European population.

METHODS

We performed a cross-sectional study including 1501 subjects (770 women and 731 men) between 18 and 80 years of age. Samples were collected after 12-14 h of fasting. Cholesterol, HDL-C, triglycerides and apoB levels were measured using direct methods. LDL-C was calculated by the Friedewald formula. Non-HDL-C was calculated as total cholesterol minus HDL-C.

RESULTS

The Spearman's rank correlations between apoB and LDL-C (r 0.86, p < 0.0001), and between apoB and non-HDL-C (r 0.91, p < 0.0001) were both significant. The proposed cut-off points for apoB, according to LDL-C goals (70, 100, 130 and 160 mg/dl) in our population are 70, 80, 100 and 115 mg/dl respectively. The proposed cut-off values for non-HDL-C are 100, 120, 150 and 190 mg/dl respectively.

CONCLUSION

The established LDL-C cut-off values could not be accurate to estimate cardiovascular risk in subjects with mild hypertriglyceridaemia, as frequently occurs in our Mediterranean population. To take into consideration the burden of atherogenic particles and better classify patients at risk we propose cut-off values for apoB or the equivalent for non-HDL-C. Prospective trials including cardiovascular variables are needed to validate our assumption.

High-sensitivity C-reactive protein can predict major adverse cardiovascular events in Korean patients with type 2 diabetes

Inflammation is thought to play a role in the pathogenesis of major adverse cardiovascular events (MACE). It has been suggested that the measurement of markers of inflammation may aid in predicting the risk of such events. Here, the relationship between high-sensitivity C-reactive protein (hs-CRP) levels and MACE in Korean patients with type 2 diabetes is assessed. A retrospective cohort study was conducted as a follow-up among 1,558 patients with type 2 diabetes and without cardiovascular diseases over a mean period of 55.5 months. A Cox proportional-hazards model was used to determine whether increased hs-CRP levels are useful as a predictor for future MACE. The hazard ratio of MACE was 1.77 (95% CI; 1.16-2.71) in subjects who had the highest hs-CRP levels (> 0.21 mg/dL) compared to subjects who had the lowest hs-CRP levels (< 0.08 mg/dL), after adjusting for age, regular physical activity, current smoking, and duration of diabetes. The present results indicate that high hs-CRP levels can act as a predictor for the MACE occurrence in Korean patients with type 2 diabetes.

Low Prevalence of Elevated ApoB Levels in Patients with Type 2 Diabetes Not Receiving Lipid-Lowering Therapy

OBJECTIVE

Cardiovascular disease (CVD) is the leading cause of death in people with type 2 diabetes. Apolipoprotein B (apoB) is known to be a better marker of CVD risk than low-density lipoprotein cholesterol (LDL-C). This study investigated apoB levels in people with type 2 diabetes.

METHODS

We obtained blood samples from 507 consenting people with type 2 diabetes who were not receiving lipid-lowering medication and who had no previous history of CVD. Subjects were divided into 3 groups: men (M), women <50 years old (W1) and women ≥50 years old (W2). Primary analysis examined lipid parameters, specifically apoB. Secondary analysis involved classifying patients according to the Canadian Diabetes Association's apoB, LDL-C and triglyceride (TG) targets.

RESULTS

We found a total mean apoB level of 0.92 g/L. Among patients who failed to achieve the LDL-C target, 28% of M, 39% of W1 and 30% of W2 met the apoB target. The proportions of individuals categorized as being above the LDL-C and apoB targets were significantly different in all 3 groups (p<0.01). When LDL-C was below target and TG was <1.5 mmol/L, 100% of M and W1 and 93% of W2 met the apoB target.

CONCLUSIONS

The discordance between the proportions of patients meeting LDL-C and apoB targets may lead to patients being erroneously classified. ApoB and LDL-C correlate very well when TG is <1.5 mmol/L, but not when ≥1.5 mmol/L. Approximately one-third of patients met both LDL-C and apoB goals. Thus, not all patients with type 2 diabetes should be considered to be at a high risk of CVD.

C-reactive protein is elevated 30 years after eclamptic pregnancy

Women with a history of preeclampsia or eclampsia (seizure during preeclamptic pregnancy) are at increased risk for cardiovascular disease after pregnancy for reasons that remain unclear. Prospective studies during pregnancy suggest that inflammation, dyslipidemia, and insulin resistance are associated with increased risk of preeclampsia. Elevated serum C-reactive protein (CRP >3 mg/L) is an indicator of inflammation and cardiovascular risk. We hypothesized that Icelandic postmenopausal women with a history of eclampsia would manifest higher concentrations of serum CRP than Icelandic postmenopausal controls with a history of uncomplicated pregnancies. We also asked whether elevated CRP is associated with the dyslipidemia and insulin resistance previously identified in this cohort. CRP, measured by high-sensitivity enzyme-linked immunoassay, was higher in women with prior eclampsia (n=25) than controls (n=28) (median mg/L [interquartile range]: 9.0 [0.9 to 13.2] versus 2.0 [0.3 to 5.1]; P<0.03). This difference remained significant after adjustment for body mass index, smoking, hormone replacement, and current age. Women with prior eclampsia clustered into either high CRP (range 8.97 to 40.6 mg/L, n=13) or lower CRP (median 1.0, range 0.05 to 3.77, n=12) subsets. The prior eclampsia/high CRP subset displayed significantly elevated systolic blood pressures, lower high-density lipoprotein (HDL) cholesterol, higher apolipoprotein B, and higher fasting insulin and homeostasis model of insulin resistance (HOMA) values compared to controls, whereas the prior eclampsia/low CRP subset differed from controls only by marginally increased apolipoprotein B. The triad of inflammation, low HDL, and insulin resistance may elevate risk for both preeclampsia/eclampsia and cardiovascular disease in later life.

The contribution of ApoB and ApoA1 measurements to cardiovascular risk assessment

LDL has been widely recognized as the major atherogenic lipoprotein and designated as the primary target for prevention of coronary heart disease (CHD); however, there is growing evidence that other triglyceride-rich lipoproteins, such as very low-density lipoprotein (VLDL) and intermediate density lipoprotein (IDL) carry atherogenic potential as well. This led to the designation of non-HDL cholesterol (HDL-C) (LDL + IDL + VLDL) as a secondary target of treatment for hyperlipidaemia. As each one of LDL, IDL and VLDL particles carries only one apolipoprotein B-100 (ApoB-100) molecule, the total ApoB value represents the total number of potentially atherogenic lipoproteins, whereas non-HDL-C provides the cholesterol content of these same lipoproteins. Recent data from epidemiological, observational and interventional studies suggest that non-HDL-C, apolipoproteins ApoA1 and ApoB may improve CHD risk assessment by identifying more high-risk individuals than the usual lipid profile alone. However, the targets for the optimal treatment of dyslipidaemia remain a subject of considerable debate. Further studies are needed to determine whether ApoB and ApoA1 are superior to conventional lipid parameters as predictors of cardiovascular disease or therapeutic targets of hyperlipidaemias. In this review, we summarize the current opinions on the use of ApoA1 and ApoB values as estimates of cardiovascular risk or as treatment goals in patients undergoing treatment for hyperlipidaemia.

Prevalence and determinants of elevated apolipoprotein B and dense low-density lipoprotein in youths with type 1 and type 2 diabetes

OBJECTIVE

The objective of the study was to assess the prevalence and determinants of elevated apolipoprotein B (apoB) and dense low-density lipoprotein (LDL) in United States youth with type 1 or type 2 diabetes.

METHODS

We conducted cross-sectional analyses of apoB concentrations, LDL density, and prevalence of elevated apoB levels and dense LDL from the SEARCH for Diabetes in Youth study, a six-center U.S.-based study of youth with diabetes onset younger than 20 years of age (2657 with type 1 and 345 with type 2).

RESULTS

Among youth with type 1 diabetes, 11% had elevated apoB (>or=100 mg/dl, 1.95 mm/liter), 8% had dense LDL (relative flotation rateor=130 mg/dl, 3.36 mm/liter). In contrast, among youth with type 2 diabetes, 36% had elevated apoB, 36% had dense LDL, but only 23% had elevated LDL-cholesterol. Dense LDL and apoB each increased with hemoglobin A1c in both types. Among type 1 diabetics in poor glycemic control (hemoglobin A1c>or=9.5%), 28% had elevated apoB, and 18% had dense LDL, whereas 72% of poorly controlled type 2 diabetics had elevated apoB and 62% had dense LDL.

CONCLUSIONS

In youth with type 1 diabetes, elevated apoB and dense LDL were not highly prevalent, whereas elevated apoB and dense LDL were common lipoprotein abnormalities in youth with type 2 diabetes. The prevalence of these risk factors substantially increased with poor glycemic control in both groups, stressing the importance of achieving and maintaining an optimal glucose control.

SHP-2 and PI3-kinase genes PTPN11 and PIK3R1 may influence serum apoB and LDL cholesterol levels in normal women

Insulin regulates apoB metabolism via activation of PI3K or regulation of MTP via MAPK/ERK signalling. SHP-2 enhances both pathways through increased IRS-1 phosphorylation. We hypothesized that variants in the SHP-2 gene PTPN11 and PI3K p85alpha subunit gene PIK3R1 may influence fasting levels of plasma apoB and/or LDL cholesterol. We tested association of tagging SNPs (tSNPs) in each gene with serum lipids in a large sample of unselected population-based Caucasian female twins (n=2771, mean age 47.4+/-12.5 years) and then tested interaction between tSNPs in determining apoB and LDL levels. PTPN11 tSNP rs11066322 was associated with apoB (P=0.007) and rs11066320 was associated with LDL cholesterol (P=0.016). PIK3R1 tSNP rs251406 was associated with apoB (P=0.0003) and rs706713 was associated with LDL cholesterol (P=0.009). PTPN11 tSNP rs11066322 interacted with PIK3R1 tSNP rs251406 in determining serum apoB levels (P=0.012) and with PIK3R1 tSNP rs40318 in determining LDL cholesterol levels (P=0.009). Association of single tSNPs with both apoB and LDL cholesterol as well as interactions between the two genes suggest that variants influencing SHP-2 activity may modulate the acute pathway by which insulin regulates these lipids.

Tesaglitazar, a dual peroxisome proliferator-activated receptor alpha/gamma agonist, improves apolipoprotein levels in non-diabetic subjects with insulin resistance

AIM

To determine the effects of the peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist tesaglitazar on serum levels of apolipoprotein (apo) A-I, apoB, and apoCIII in non-diabetic insulin-resistant subjects.

METHODS

This randomized, double-blind, multicentre, placebo-controlled trial examined the effect of tesaglitazar (0.1, 0.25, 0.5, and 1mg) once daily for 12 weeks on apolipoprotein levels in 390 abdominally obese subjects with hypertriglyceridaemia.

RESULTS

Tesaglitazar dose-dependently increased serum concentrations of apoA-I (p<0.009) and decreased concentrations of apoB (p<0.0001), the apoB/apoA-I ratio (p<0.0001), and apoCIII (p<0.0001). Similar improvements were observed in all subgroups of subjects, where individuals were grouped according to age, gender, baseline body mass index, serum triglycerides and high-density lipoprotein cholesterol levels. Low-density lipoprotein particle concentrations were also dose-dependently reduced by tesaglitazar (p<0.0001).

CONCLUSION

Although tesaglitazar is no longer in clinical development, these data indicate that dual PPARalpha/gamma agonism may be a useful pharmacological approach to improve the atherogenic dyslipidaemia associated with insulin resistance.

Management of dyslipidemia in diabetes

Diabetes is associated with a high risk of cardiovascular disease. The management of dyslipidemia, a well-recognized and modifiable risk factor among patients with type 2 diabetes, is an important element in the multifactorial approach to prevent coronary heart disease. Diabetic dyslipidemia typically consists of elevated triglyceride, low high-density lipoprotein cholesterol (HDL-C), and the predominance of small dense low-density lipoprotein (LDL) particles. LDL cholesterol (LDL-C) levels in patients with diabetes are similar to those found in the rest of the population. During the past few years, clinical trials have provided evidence that lipid-lowering therapy has a similar beneficial effect on cardiovascular outcomes in diabetic and nondiabetic individuals. According to current guidelines, the primary lipid target is an LDL-C <100 mg/dL (<70 mg/dL in very high-risk patients) and, to this end, statins are the agents of choice. The appropriate management of dyslipidemia in patients with diabetes, particularly in individuals with low LDL-C, remains controversial. To achieve lipid targets, attention should be directed first toward nonpharmacologic therapeutic interventions to control dyslipidemia, such as diet, exercise, smoking cessation, weight loss, and glycemic control. Statin therapy is recommended for most subjects but, frequently, a combination of lipid-lowering agents is required. A number of combinations are possible, and several factors should be considered to improve the safety of this strategy.

Influence of hepatic steatosis (fatty liver) on severity and composition of dyslipidemia in type 2 diabetes

OBJECTIVE

The objective of this study was to examine the associations between the severity of hepatic steatosis and dyslipidemia in type 2 diabetes, including circulating apolipoprotein B100 (apoB) concentrations and lipoprotein particle size and numbers.

RESEARCH DESIGN AND METHODS

Computed tomography imaging was used to assess hepatic fat content and adipose tissue distribution in 67 men and women with type 2 diabetes, withdrawn from antidiabetic medications preceding the study. Fasting serum lipoprotein number and size was determined by nuclear magnetic resonance. Insulin sensitivity was measured with a glucose clamp and a [6,6-(2)H(2)]glucose isotope infusion.

RESULTS

Two-thirds of the cohort had fatty liver. Hepatic steatosis correlated with serum triglycerides (r = 0.40, P < 0.01) and lower HDL cholesterol (r = -0.31, P < 0.05). ApoB and LDL cholesterol did not, being virtually identical in those with or without steatosis. The association between serum triglycerides and hepatic steatosis was largely accounted for by greater triglyceride enrichment in VLDL particles, which were larger. Severe steatosis was also associated with 70% higher small, dense LDL concentrations. Visceral obesity did not fully explain these associations, and hepatic steatosis was better correlated with triglycerides than with hyperglycemia or hepatic insulin resistance (P > 0.05).

CONCLUSIONS

The presence of hepatic steatosis in type 2 diabetes does not appear to affect apoB levels, but potentially increases atherogenesis by increasing triglycerides, reducing HDL levels, and increasing small, dense LDL.

A potential role of apolipoprotein B in the risk stratification of diabetic patients with dyslipidaemia

Diabetic dyslipidaemia is characterised by retention of atherogenic particles, which are depleted of cholesterol. Therefore, calculating or measuring LDL or VLDL cholesterol may not reflect the actual number of these atherogenic particles. We examined the potential role of apolipoprotein B in the risk stratification of Omani patients with type 2 diabetes and dyslipidaemia. Two hundred and twenty-one subjects with type 2 diabetes and 67 healthy controls were recruited. Diabetic subjects had significantly higher serum levels of triglycerides (P<0.0001), non-HDL cholesterol (P<0.0001), and total/HDL cholesterol ratio (P<0.04) and lower levels of HDL cholesterol (P<0.0001) and lipoprotein(a) compared to nondiabetic subjects. The ratio of apoB/LDL cholesterol ratio was significantly higher (P<0.002) among diabetic compared to nondiabetic subjects. Sixty percent of the diabetic subjects with abnormal apoB of >1.2g/L had an LDL cholesterol of less than 4.2 mmol/L compared to 7% of the nondiabetic subjects (sensitivity; 40% versus 93%, respectively). Furthermore, diabetic subjects with ischaemic heart disease (IHD) had significantly higher (P<0.003) apoB/non-HDL cholesterol ratio compared to those without IHD. These findings suggest that the ratios of apoB/LDL cholesterol and apoB/non-HDL cholesterol may have a role in the risk stratification of diabetic patients with dyslipidaemia.

Management of diabetic dyslipidemia

Identification and management of dyslipidemia is an important element in the multi-factorial approach to prevent coronary heart disease. Diabetic dyslipidemia typically consists of elevated triglyceride, low high-density lipoprotein cholesterol, predominance of small, dense low-density lipoprotein (LDL) particles, and average LDL cholesterol (LDL-C). Lipid-lowering therapy has a beneficial effect on cardiovascular outcomes. Statin treatment is beneficial in patients who are older than 40 years of age, irrespective of the LDL-C value. To achieve lipid targets, attention should be directed first toward nonpharmacologic therapeutic interventions, such as diet, exercise, smoking cessation, weight loss, and improving glycemic control. Although statin therapy is recommended for most subjects, judicious use of combination therapy should be considered in the highest risk subjects.

Relation between XbA1 apolipoprotein B gene polymorphism and cardiovascular risk in a type 2 diabetic cohort

AIM

To evaluate in a prospective study the association of XbA1 apolipoprotein B (apoB) gene polymorphism with lipid parameters and cardiovascular (CV) events in a type 2 diabetic cohort.

METHODS AND RESULTS

A cohort of 212 type 2 diabetic patients, free of any cardiovascular complication, was studied. Cardiovascular events were registered for all the patients for 5 years. XbA1 apolipoprotein B gene polymorphism was analysed by PCR-RFLP method. A mild increase in HbA1c was found in X+X+ carriers (P = 0.014). Despite this lower glycemic control, there were no differences between genotype subgroups for lipid parameters except for apoB, significantly higher in X+X+ than in X-X- subjects. In univariate analysis, the cardiovascular events rate was higher in X-X- but did not reach statistical significance (P =0.07). In stepwise multivariate regression analysis, cardiovascular events risk was significantly higher in X- carriers (P = 0.014) and also in smokers, microalbuminuric and older patients.

CONCLUSIONS

We report for the first time in a prospective study the association of XbA1 apolipoprotein B gene polymorphism and cardiovascular events in a diabetic population. The mechanism underlying the excess of cardiovascular risk in X- carriers, despite a better metabolic profile, is likely to involve a linkage disequilibrium between apolipoprotein B gene locus and another gene locus related to cardiovascular risk.

Effect of improving glycemic control on low-density lipoprotein particle size in type 2 diabetes

The current study sought to assess the effect of improving glycemic control in type 2 diabetes on the components of diabetic dyslipidemia, especially low-density lipoprotein (LDL) size. A total of 33 type 2 diabetic patients (48.5% women, age 59.6 +/- 11.1 years, body mass index [BMI] 28.9 +/- 4.9, diabetes duration 6 [0 to 40] years, 40.7% on insulin) were seen at the hospital because of poor glycemic control (hemoglobin A(1c) [HbA(1c)] 10.33% +/- 1.89%). Triglyceride, LDL-cholesterol (LDLc, Friedewald/ ultracentrifugation), high-density lipoprotein HDL-cholesterol (HDLc, direct method), apolipoproteins AI (apoAI) and B (apoB) (immunoturbidimetry), and LDL size (gradient gel electrophoresis) were measured at baseline and after improvement in glycemic control (decrease >/= 1 percentage point in HbA(1c) and final HbA(1c) </= 8%). Improvement in glycemic control (HbA(1c) 7.01% +/- 0.63%, P <.0005 v baseline) after a follow-up of 3.5 (range, 1 to 13) months resulted in a significant reduction in LDLc (3.34 +/- 1.02 v 3.62 +/- 1.15 mmol/L, P <.05) and apoB (1.07 +/- 0.25 v 1.17 +/- 0.29 g/L, P <.01) and an increase in HDLc (1.21 +/- 0.32 v 1.13 +/- 0.34 mmol/L, P <.05) and apoAI (1.36 +/- 0.24 v 1.27 +/- 0.24 mmol/L, P < 0.01) in the whole group, and an increase in LDL particle size (25.61 +/- 0.53 v 25.10 +/- 0.31 nm, P <.005) in the 14 patients showing LDL phenotype B at baseline. No significant changes were seen in body weight or BMI. We conclude that improvement of glycemic control in type 2 diabetes improves most of the components of diabetic dyslipidemia, including a shift towards larger LDL particles in subjects with phenotype B.

Postprandial lipidemia is normal in non-obese type 2 diabetic patients with relatively preserved insulin secretion

To assess postprandial lipidemia in normotriglyceridaemic type 2 diabetic patients treated with diet only, 12 non-obese patients (8 males, hemoglobin A(1c) [HbA(1c)] 6.80 +/- 0.67%) and 14 controls of similar age, body mass index (BMI), and fasting triglyceride (Tg) were given a test meal (58 g fat, 100,000 IU vitamin A). Fasting low-density lipoprotein (LDL) cholesterol (LDLc), high-density lipoprotein (HDL) cholesterol (HDLc), free fatty acids, and apolipoprotein B (apoB), and fasting and postprandial Tg, retinylpalmitate (RP), LDL size, glucose, and insulin were measured. The homeostasis assessment model (HOMA) index and lipoprotein (Lpl) and hepatic (HL) lipase activities were estimated. Patients showed lower fasting HDLc (1.12 +/- 0.26 v 1.40 +/- 0.28 mmol/L, P =.02) and a trend towards smaller LDL particles, which was significant 4 hours postprandially (25.86 +/- 0.40 v 26.16 +/- 0.30 nm, P =.04). The area under the curve of Tg (AUC-Tg) and RP, and Lpl were similar, but HL was higher in patients (156.63 +/- 23.89 v 118 +/- 43.27 U/L, P =.011). HL correlated inversely with LDL size and directly with the HOMA index. In conclusion, normotriglyceridemic type 2 diabetic patients with insulin resistance but relatively preserved insulin secretion show low fasting HDLc and increased HL, but normal postprandial lipidemia.

Non-HDL cholesterol and apolipoprotein B in the dyslipidemic classification of type 2 diabetic patients

OBJECTIVE

To compare non-HDL cholesterol (HDLc) and apolipoprotein B (apoB) in the identification of nonconventional high-risk dyslipidemic phenotypes in type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

Total cholesterol and triglycerides, HDLc, LDL cholesterol, non-HDLc, apolipoprotein B (apoB), and LDL size were determined in 122 type 2 diabetic patients (68% male, aged 59.6 +/- 9.7 years, and HbA(1c) 7.5% [range 5.2-16.0]). They were then classified as normo- and hypertriglyceridemic if their triglyceride concentrations were below/above 2.25 mmol/l, as normo/hyper-non-HDLc if non-HDLc concentrations were below/above 4.13 mmol/l, and as normo- and hyperapoB if apoB concentrations were below/above 0.97 g/l. Both classifications were compared (concordance assessed with the kappa index), and low HDLc and LDL phenotype B were identified in each category.

RESULTS

A total of 26 patients were hypertriglyceridemic and 96 were normotriglyceridemic. All hypertriglyceridemic subjects had increased non-HDLc, whereas 24 had increased apoB (kappa= 0.95). In the normotriglyceridemic group, 44 had increased non-HDLc, 68 had increased apoB, and 25 of the 52 patients with normal non-HDLc had increased apoB (kappa= 0.587). Low HDLc and LDL phenotype B were similarly distributed into the equivalent categories.

CONCLUSIONS

Non-HDLc and apoB are equivalent risk markers in hypertriglyceridemic patients, but apoB identifies additional patients with high-risk dyslipidemic phenotypes in normotriglyceridemic type 2 diabetic patients.

Regulation of microsomal triglyceride transfer protein gene by insulin in HepG2 cells: roles of MAPKerk and MAPKp38

Microsomal triglyceride transfer protein (MTP) is rate limiting for the assembly and secretion of apolipoprotein B-containing lipoproteins. Elevated hepatic MTP mRNA level, presumably as a result of impaired insulin signaling, has been implicated in the pathophysiology of dyslipidemia associated with insulin resistance/type 2 diabetes. In this study, we showed that insulin decreases MTP mRNA level mainly through transcriptional regulation in HepG2 cells. We further characterized the corresponding signal transduction pathway, using chemical inhibitors and constitutively active and dominant negative forms of regulatory enzymes. We demonstrated that insulin inhibits MTP gene transcription through MAPK(erk) cascade but not through the PI 3-kinase pathway. Activation of ras through farnesylation is not a prerequisite for the inhibition. In addition, cellular MAPK(erk) and MAPK(p38) activities play a counterbalancing role in regulating the MTP gene transcription. These complex regulations may represent a means to fine-tuning MTP gene transcription in response to a diverse set of environmental stimuli and may have important implications for the onset and development of diabetes-associated dyslipidemia.

The effect of VLDL particles on the accuracy of a direct LDL-cholesterol method in type 2 diabetic patients

OBJECTIVE

To assess the accuracy of the direct method LDL-c Plus, in type 2 diabetic patients.LDL-c Plus was measured in 64 consecutive samples of type 2 diabetic patients and compared with betaquantification (BQ), Friedewald's and an alternative formula.

METHODS

LDL-c Plus was also measured in the VLDL (d<1.006 Kg/L) fraction of these samples and in total serum and the VLDL fraction of a phenotype III patient, before and after diluting it with saline or VLDL from normolipidemic subjects.

RESULTS

LDL-c Plus showed a significant, constant bias (-8.5 +/- 5.6%) against BQ which correlated with VLDL-cholesterol/total triglyceride ratio (r = 0.760, p < 0.0005); bias decreased to zero when the ratio increased. In the VLDL fraction of the diabetic patients and the phenotype III patient LDL-c Plus measured 20.7 +/- 11.6% and 56.2% of the cholesterol, respectively. Dilution with saline did not alter the latter percentage, whereas dilution with normolipidemic VLDL reduced it showing that LDL-c Plus recognized cholesterol-enriched particles in the d<1.006 Kg/L. Friedewald's formula also showed a significant, constant bias (-3.1 +/- 6.4%) against BQ, whereas the alternative formula did not (0.5 +/- 6.1%). Both calculations classified patients better than LDL-c Plus did at NCEP cut-off points.

CONCLUSIONS

In type 2 diabetic patients, LDL-c Plus underestimates LDL-c but measures cholesterol associated to IDL particles in the d<1.006 Kg/L fraction. Although LDLc-Plus might be a better cardiovascular risk estimator when well standardized, at the moment, it does not seem to be superior to calculations.

Evidence for joint action of genes on diabetes status and CVD risk factors in American Indians: the strong heart family study

OBJECTIVES

Previous research among American Indians of the strong heart family study (SHFS) has demonstrated significant heritabilities for CVD risk factors and implicated diabetes as an important predictor of several of the phenotypes. Moreover, we recently demonstrated that genetic effects on CVD risk factors differed in diabetic and nondiabetic individuals. In this paper, we investigated whether a significant genetic influence on diabetes status could be identified, and whether there is evidence for joint action of genes on diabetes status and related CVD risk factors.

METHODS AND RESULTS

Approximately 950 men and women, age 18 or older, in 32 extended families, were examined between 1997 and 1999. We estimated the effects of genes and environmental covariates on diabetes status using a threshold model and a maximum likelihood variance component approach. Diabetes status exhibited a residual heritability of 22% (h2=0.22). We also estimated the genetic and environmental correlations between diabetes susceptibility and eight risk factors for CVD. All eight CVD risk factors displayed significant genetic correlations with diabetes status (BMI (rhoG=0.55), fibrinogen (rhoG=0.40), HDL-C (rhoG=-0.37), ln triglycerides (rhoG=0.65), FAT (rhoG=0.38 ), PAI-1 (rhoG=0.67), SBP (rhoG=0.57), and WHR (rhoG=0.58)). Three of eight traits (HDL-C (rhoE=-0.32), ln triglycerides (rhoE=0.33), and fibrinogen (rhoE=0.20)) displayed significant environmental correlations with diabetes status.

CONCLUSIONS

These findings suggest that in the context of a high prevalence of diabetes, still unidentified diabetes genes may play an important role in influencing variation in CVD risk factors.

Role of Spirulina in the Control of Glycemia and Lipidemia in Type 2 Diabetes Mellitus

Spirulina, with its high concentration of functional nutrients, is emerging as an important therapeutic food. This study aimed to evaluate the hypoglycemic and hypolipidemic role of Spirulina. Twenty-five subjects with type 2 diabetes mellitus were randomly assigned to receive Spirulina (study group) or to form the control group. At baseline, the control and study groups were matched for various variables. The efficacy of Spirulina supplementation (2 g/day for 2 months) was determined using the preintervention and postintervention blood glucose levels, glycosylated hemoglobin (HbA(1c)) levels, and lipid profiles of the diabetic subjects. Two-month supplementation with Spirulina resulted in an appreciable lowering of fasting blood glucose and postprandial blood glucose levels. A significant reduction in the HbA(1c) level was also observed, indicating improved long-term glucose regulation. With regard to lipids, triglyceride levels were significantly lowered. Total cholesterol (TC) and its fraction, low-density lipoprotein cholesterol (LDL-C), exhibited a fall coupled with a marginal increase in the level of high-density lipoprotein cholesterol (HDL-C). As a result, a significant reduction in the atherogenic indices, TC:HDL-C and LDL-C: HDL-C, was observed. The level of apolipoprotein B registered a significant fall together with a significant increment in the level of apolipoprotein A1. Therefore, a significant and favorable increase in the ratio of A1:B was also noted. These findings suggest the beneficial effect of Spirulina supplementation in controlling blood glucose levels and in improving the lipid profile of subjects with type 2 diabetes mellitus.

Interaction between angiotensin-converting enzyme genotype and glycaemic control influences lipoprotein levels in type 2 diabetes mellitus

AIMS

To evaluate the influence of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism on lipid levels in patients with Type 2 diabetes.

PATIENTS AND METHODS

109 patients with Type 2 diabetes were included. The patients were not on any lipid-lowering treatment. The groups with different ACE genotypes had similar ages, sex distributions, body mass indices, systolic blood pressures and indices of glycaemic control. ACE gene I/D polymorphism was determined using polymerase chain reaction.

RESULTS

The mean apolipoprotein B (apoB) level was significantly higher in the group of DD homozygotes compared with the subjects with at least one insertion allele (DD: 1.21 +/- 0.25 g/l vs. ID + II: 1.04 +/- 0.27 g/l; P = 0.007). Significant correlations between glycated haemoglobin (HbA1c) and both apoB and cholesterol levels were found (r = 0.27; P < 0.01). For the apoB, this correlation was highly significant in the DD-genotype subgroup (r = 0.54; P < 0.01), and was not significant in the subgroup of patients with genotypes ID or II. In the multivariate analysis, HbA1c and the interaction of genotype DD with HbA1c were significant independent predictors of apoB (r2 = 0.17) and cholesterol levels.

CONCLUSION

The present study showed that the interaction between the DD genotype of angiotensin-converting enzyme and chronic hyperglycaemia (expressed by HbA1c level) is related to higher plasma levels of atherogenic lipoproteins, such as apoB and cholesterol, in patients with Type 2 diabetes.

Relationships of apolipoprotein B(100) with the metabolic syndrome in Type 2 diabetes mellitus

The current study assessed whether features of the metabolic syndrome are associated with higher apolipoprotein B(100) (apoB(100)) levels in people with Type 2 diabetes (n = 298) not taking lipid-lowering drugs. Body-mass index (BMI), waist:hip ratio (WHR), urinary albumin excretion rate, presence or absence of hypertension, uric acid levels, and apoB(100) levels were assessed. Both higher BMI and urinary albumin excretion rate were associated with higher apoB(100) levels (1.02 +/- 0.25 ( +/- S.D.) g/l in normal weight, 1.07 +/- 0.22 g/l in overweight and 1.14 +/- 0.25 g/l in obese individuals; P < 0.01; 1.09 +/- 0.23 g/l in normoalbuminuric patients, 1.06 +/- 0.22 g/l if urinary albumin excretion rate 20-50 microg/min and 1.17 +/- 0.27 g/l if urinary albumin excretion rate > 50 microg/min; P < 0.05). An association between the number of features of the metabolic syndrome and higher apoB(100) levels was found (1.03 +/- 0.22 g/l if no features, 1.08 +/- 0.25 g/l if one feature, 1.11 +/- 0.20 g/l if two features and 1.15 +/- 0.27 g/l if > 2 features; P for trend < 0.01). Thus apoB(100) levels show an association with the metabolic syndrome and, hypothetically, to insulin-insensitivity in Type 2 diabetes. BMI (but not WHR) and urinary albumin excretion rate accounted for most of the power of this relationship.

Hepatic expression of microsomal triglyceride transfer protein and in vivo secretion of triglyceride-rich lipoproteins are increased in obese diabetic mice

Secondary hyperlipidemia is a major cardiovascular risk factor in individuals with type 2 diabetes. Increased hepatic production of apolipoprotein B (apoB)-containing lipoproteins contributes to the elevated plasma levels, but the mechanism is poorly understood. Recent results have established that microsomal triglyceride transfer protein (MTP) is rate limiting for the assembly and secretion of apoB-containing lipoproteins. To better understand the mechanism of type 2 diabetes-associated hyperlipidemia, we quantified hepatic MTP mRNA levels, hepatic microsomal triglyceride transfer activity, and in vivo triglyceride secretion from the liver in two diabetic mouse models. Obese diabetic (ob/ob) mice had 45% higher (P = 0.006) hepatic MTP mRNA levels, 54% higher (P < 0.0001) microsomal triglyceride transfer activity, and 70% higher (P < 0.0001) in vivo triglyceride secretion rates compared with ob/+ control mice. In contrast, in lean streptozotocin-treated diabetic mice, hepatic MTP mRNA levels were unchanged, whereas microsomal triglyceride transfer activity and in vivo triglyceride secretion rates were marginally decreased. These studies suggest that obesity-induced type 2 diabetes in mice confers increases in hepatic MTP expression and secretion of triglyceride-rich lipoproteins. High blood glucose and altered hepatic expression of sterol regulatory element binding protein genes play a minor role in this diabetic response.

Hypertriglyceridemic hyperapoB in type 2 diabetes

OBJECTIVES

Much less attention has been paid to LDL in type 2 diabetes than to VLDL or HDL. In particular, there are few data on apoB levels in these patients. Moreover, most reports have focused on mean lipoprotein levels and consequently there is little information on the frequencies of the various dyslipidemic phenotypes.

RESEARCH DESIGN AND METHODS

Plasma and lipoprotein lipids, apoB and apoA1 were measured by standardized methods. LDL particle size was determined by PAGE. The total cohort was divided into phenotypes by two different methods. The first was based on triglycerides (> or = or <1.5 mmol/l) and LDL cholesterol (> or = or <4 mmol/l), whereas the second was based on triglycerides (> or = or <1.5 mmol/l) and apoB (> or = or <120 mg/dl).

RESULTS

For the overall cohort, plasma triglycerides were elevated (2.13 +/- 1.6 mmol/l), total and LDL cholesterol were normal (5.34 +/- 1.1 and 3.28 +/- 0.88 mmol/l, respectively), and peak LDL size was reduced (252.9 +/- 5.8 A). HDL cholesterol was between the 25th and 50th percentiles of the general population (1.12 +/- 0.36 mmol/l). The average level of apoB was 114 +/- 29 mg/dl, a value that is between the 50th and 75th percentiles of the general population and is higher than that for LDL cholesterol, which was between the 25th and the 50th percentiles of the population. The results of the phenotyping analysis were as follows. Using the conventional approach, only 23% has abnormal LDL, i.e., an elevated LDL cholesterol level. Using the new approach, almost 40% has an elevated apoB and therefore an elevated LDL particle number. Only 12.8% has combined hyperlipidemia based on the conventional approach, whereas almost one-third had the equivalent, hypertriglyceridemic hyperapoB-based on the new algorithm. The severity of the dyslipoproteinemia in this group was noteworthy. Although the average LDL cholesterol was 3.91 mmol/l, a value just below the 75th percentile of the general population, the average apoB was 145 mg/dl, a value that approximates the 95th percentile of the population.

CONCLUSIONS

The dyslipidemic profile of patients with type 2 diabetes is not uniform. A substantial group have normal lipids and normal LDL particle number and size whereas others have markedly abnormal profiles. Diagnosis based on triglycerides and apoB rather than triglycerides and LDL cholesterol revealed that more than one in five had hypertriglyceridemic hyperapoB, which is characterized by hypertriglyceridemia, marked elevation of LDL particle number, small dense LDL, and low HDL, a constellation of abnormalities that is associated with markedly accelerated atherogenesis and therefore justifies intensive medical therapy.

Pathophysiology of hypertension and endothelial dysfunction in patients with diabetes mellitus

There is compelling evidence for endothelial dysfunction in both type 1 and type 2 diabetics. This dysfunction is manifest as blunting of the biologic effect of a potent endothelium-derived vasodilator, nitric oxide, and increased production of vasoconstrictors such as angiotensin II, ET-1, and cyclooxygenase and lipoxygenase products of arachidonic acid metabolism. These agents and other cytokines and growth factors whose production they stimulate cause acute increases in vascular tone, resulting in increases in blood pressure, and vascular and cardiac remodeling that contributes to the microvascular, macrovascular, and renal complications in diabetes. Reactive oxygen species, overproduced in diabetics, serve as signaling molecules that mediate many of the cellular biochemical reactions that result in these deleterious effects. Adverse vascular consequences associated with endothelial dysfunction in diabetes mellitus are Decreased nitric oxide formation, release, and action Increased formation of reactive oxygen species Decreased prostacyclin formation and release Increased formation of vasoconstrictor prostanoid Increased formation and release of ET-1 Increased lipid oxidation Increased cytokine and growth factor production Increased adhesion molecule expression Hypertension Changes in heart and vessel wall structure Acceleration of the atherosclerotic process Treatment with antioxidants and with inhibitors of the renin-angiotensin system may reverse some of the pathologic vascular changes associated with endothelial dysfunction.

Apo(B)-dependent dyslipidemic phenotypes in type 1 diabetic patients

BACKGROUND

The prevalence of apo(B)-dependent dyslipidemic phenotypes, which are associated with cardiovascular disease, is increased in normocholesterolemic type 2 diabetic patients. Our aim was to determine the impact of including apo(B) in the evaluation of normocholesterolemic type 1 diabetic patients.

METHODS

A total of 123 type 1 diabetic patients (47% male, age 36.6+/-12.5 years) were included. The apo(B) cut-off point (1.14 g/l) was obtained from a group of 53 normolipidemic control subjects of similar age and gender distribution; for low density lipoprotein cholesterol (LDLc), triglycerides, and high density lipoprotein cholesterol (HDLc), we used the cut-off points recommended by the National Cholesterol Education Program. LDLc was determined by ultracentrifugation or Friedewald's equation, depending on triglyceride concentrations, and apo(B) by immunoturbidimetry.

RESULTS

A total of 113 (92%) type 1 diabetic patients were normocholesterolemic, and 13% of these were dyslipidemic. The frequency of hyperapo(B) was similar in normocholesterolemic patients and controls (6.2 vs. 9.4%, respectively). Diabetic patients with hyperapo(B) had poorer glycemic control, higher total cholesterol, triglycerides, and LDLc, and a lower HDLc and LDLc/apo(B) ratio.

CONCLUSIONS

Unlike type 2 diabetes, type 1 diabetes is not associated with an increased prevalence of hyperapo(B)-dependent dyslipidemic phenotypes. Thus, only in patients with poor glycemic control who display other components of diabetic dyslipidemia, typical for type 2 diabetes, does determining apo(B) concentrations provide additional information in type 1 diabetes.

Lipids and risk assessment

Because a standard lipid panel can misrepresent lipoprotein abnormalities that contribute to atherosclerosis, more detailed laboratory analysis should be considered in a patient whose level of risk is unclear. This is especially important for patients who have a family history of premature coronary heart disease of uncertain etiology. Such testing is analogous to performing a more advanced imaging procedure when a plain x-ray lacks the sensitivity to define an anatomic derangement. In selected situations, measuring apolipoprotein B, lipoprotein (a), low-density lipoprotein, or high-density lipoprotein subfractions, or homocysteine can markedly clarify cardiovascular risk. This review describes seven men, themselves cardiologists, who had misinterpreted their own risk based on conventional lipid tests. With further evaluation, one of these men was reassured that he had lower risk than he had feared. Six of the men had greater risk than previously recognized.

Risk variables for coronary artery disease in Asian Indians

No large study from India has addressed the association of risk variables with coronary artery disease (CAD) in angiographically proved cases. In this study, we analyzed the association of anthropometric variables, lipoproteins, and coagulation parameters with CAD in those cases proved by coronary angiography. A cross-sectional study of 447 men > or = 25 years old, classified as with CAD or without CAD, was performed. Men treated with aspirin or lipid-lowering agents, and those with renal, hepatic, or thyroid diseases were excluded. Associations of these variables with CAD were evaluated by univariate and multiple logistic regression analyses. The effect of diabetes on the CAD profile was also analyzed. Prevalences of diabetes and hypertension were significantly higher among those with CAD (p <0.001 for both). Lipid profile abnormalities, except lipoprotein (Lp(a)), were associated with CAD. Antibodies to oxidized low-density lipoprotein was higher in patients with CAD. Fibrinogen levels were higher in CAD, but plasminogen activator inhibitor-1 did not show an association with CAD. In the multiple logistic regression analysis, age, body mass index, very-low-density lipoprotein cholesterol, total to high-density lipoprotein cholesterol ratio, and fibrinogen showed significant independent association with CAD. Several lipid abnormalities were associated with CAD in Asian Indians, but no significant association was seen with Lp(a) levels.

Beneficial effects of a soy-based dietary supplement on lipid levels and cardiovascular risk markers in type 2 diabetic subjects

OBJECTIVE

Consumption of soy protein has recently been shown to improve the blood lipid levels in nondiabetic subjects. The purpose of this study was to evaluate if a dietary supplement of soy protein, isoflavones, and cotyledon fiber (Abalon) affects cardiovascular risk markers, blood glucose, and insulin levels in type 2 diabetic subjects.

RESEARCH DESIGN AND METHODS

Twenty type 2 diabetic subjects participated in a crossover trial. They were randomized to double-blind supplementation for 6 weeks with Abalon (soy protein [50 g/day] with high levels of isoflavones [minimum 165 mg/day] and cotyledon fiber [20 g/day]) or placebo (casein [50 g/day] and cellulose [20 g/day]), separated by a 3-week wash-out period.

RESULTS

The results are expressed as means +/- SD. The percentage mean treatment difference between Abalon and placebo demonstrated significantly lower mean values after Abalon for LDL cholesterol (10 +/- 15%, P < 0.05), LDL/UHDL ratio (12 +/- 18%, P < 0.05), apolipoprotein (apo) B100 (30 +/- 38%, P < 0.01), triglycerides (22 +/- 10%, P < 0.05), and homocysteine (14 +/- 21%, P < 0.01), whereas the total cholesterol value tended to be less significant but still lower (8 +/- 15%, P < 0.08). No change occurred in HDL cholesterol, apo B100/apo A1 ratio, plasminogen activator inhibitor 1, factor VIIc, von Willebrand factor, fibrinogen, lipoprotein(a), glucose, HbA1c, or 24-h blood pressure.

CONCLUSIONS

These results indicate beneficial effects of dietary supplementation with Abalon on cardiovascular risk markers in type 2 diabetic subjects. This improvement is seen even in individuals with near-normal lipid values.

Dyslipoproteinaemia in postmenopausal women with a history of eclampsia

OBJECTIVE

To test the hypothesis that postmenopausal women with a history of eclampsia manifest a more high risk lipid profile than postmenopausal women with a history of normal pregnancy.

SETTING

The Department of Obstetrics and Gynaecology, National University Hospital, Reykjavik, Iceland, and the Magee-Womens Research Institute, Pittsburgh, Pennsylvania, USA.

PARTICIPANTS

Thirty Icelandic women with a history of eclampsia, aged between 50 and 67 years at the time of re-examination (cases) were individually matched for current age, and for age and parity at index pregnancy, to 30 unrelated Icelandic women with a history of normal pregnancy (controls).

METHODS

The participating women completed a health and family history questionnaire and underwent a physical examination. Fasting plasma low density lipoprotein diameter, serum lipids, insulin, and glucose were measured.

RESULTS

Mean low density lipoprotein size was significantly smaller and apolipoprotein B concentration was higher in women with prior eclampsia. The percentage of cases receiving blood pressure medication (33%) was significantly greater than controls (6.7%). Thirteen cases had had hypertensive complications in at least one other pregnancy (recurrent subgroup); postmenopausally, these women displayed significantly increased diastolic blood pressures, smaller-sized low density lipoprotein, increased apolipoprotein B, decreased high density lipoprotein2 (HDL2) cholesterol, and increased total cholesterol: HDL cholesterol ratio compared with their controls. Fourteen cases were normotensive in all other pregnancies (nonrecurrent); these showed no differences from their controls.

CONCLUSIONS

Dyslipoproteinaemia is more prevalent among postmenopausal women with prior eclampsia, especially with recurrent hypertension in pregnancy, than in postmenopausal women with prior normal pregnancies.