Apoprotein(a) phenotypes and plasma lipoprotein(a) concentration in patients with diabetes mellitus

Lipoprotein (a) and the Occurrence of Lipid Disorders and Other Cardiovascular Risk Factors in Patients without Diagnosed Cardiovascular Disease

Background: Elevated lipoprotein (a) [Lp(a)] concentrations are linked mainly to genetic factors. The relationship between Lp(a) and other lipid disorders or cardiovascular (CV) risk factors has been less investigated. The aim of this study was to assess the occurrence of lipid disorders and other CV risk factors according to Lp(a) concentrations. Methods: A cross-sectional analysis of 200 primary-care patients who had not been diagnosed with CV disease was conducted. The following risk factors were assessed: older age, history of hypertension, diabetes mellitus or dyslipidemia, smoking, lack of physical activity, body mass index (BMI), and waist circumference. The following lipid parameters were measured: total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and small, dense LDL (sdLDL-C). Patients were divided into two groups based on their Lp(a) concentrations: <30 mg/dL and ≥30 mg/dL. Results: In 70% of patients, the Lp(a) concentration was <30 mg/dL. The concentrations of lipid parameters did not differ between the groups. The rate of patients with sdLDL-C >1.0 mmol/L was higher in the low-Lp(a) group (10.0 vs. 1.7%, p = 0.04), with no significant differences regarding the other analyzed lipid disorders (p > 0.05). Both in the low- and high-Lp(a) group, most patients had two other abnormal lipid factors (45.0% and 60.0%, respectively). The distribution of impaired lipid parameters (p = 0.41) and other CV risk factors (p = 0.16) was similar in both groups. There was a lower rate of patients >60 years old (15.0% vs. 32.9%, p = 0.01) and with a BMI ≥ 25 kg/m2 (46.7% vs. 63.6%, p = 0.026) in the high-Lp(a) group, and previously diagnosed hyperlipidemia was more prevalent in this group (65.0% vs. 47.1%, p = 0.02). The occurrence of other cardiovascular risk factors did not differ significantly between the Lp(a) groups (p > 0.05). In the high-Lp(a) group, the highest proportion (25.0%) had two CV risk factors, and in the low-Lp(a) group, 31.4% had four CV risk factors. Conclusions: An elevated Lp(a) concentration is not related to the number of conventional CV risk factors or other impairment major lipid parameters.

Lipoprotein (a): impact by ethnicity and environmental and medical conditions

Levels of lipoprotein (a) [Lp(a)], a complex between an LDL-like lipid moiety containing one copy of apoB, and apo(a), a plasminogen-derived carbohydrate-rich hydrophilic protein, are primarily genetically regulated. Although stable intra-individually, Lp(a) levels have a skewed distribution inter-individually and are strongly impacted by a size polymorphism of the LPA gene, resulting in a variable number of kringle IV (KIV) units, a key motif of apo(a). The variation in KIV units is a strong predictor of plasma Lp(a) levels resulting in stable plasma levels across the lifespan. Studies have demonstrated pronounced differences across ethnicities with regard to Lp(a) levels and some of this difference, but not all of it, can be explained by genetic variations across ethnic groups. Increasing evidence suggests that age, sex, and hormonal impact may have a modest modulatory influence on Lp(a) levels. Among clinical conditions, Lp(a) levels are reported to be affected by kidney and liver diseases.

Sex differences in cardiovascular disease risk in adolescents with type 1 diabetes

BACKGROUND

Cardiovascular disease is seen at a younger age and at a higher prevalence in patients with type 1 diabetes than in the general population. It is well described that women with type 1 diabetes have a higher relative risk of cardiovascular disease than men with type 1 diabetes, unlike that seen in the general population. The pathophysiology behind this is unknown.

OBJECTIVE

We performed a cross-sectional study to examine sex differences in cardiovascular disease risk factors in adolescents with type 1 diabetes between ages 13 and 20 years, compared with children of a similar age without type 1 diabetes.

METHODS

All patients underwent a dual energy x-ray absorptiometry scan to measure body composition and a pulse wave test measure of arterial elasticity. Fasting serum lipid levels, apolipoprotein B, and apolipoprotein C-III levels were measured in each patient. Twenty-nine children with type 1 diabetes (10 girls, 19 boys) and 37 healthy children (18 girls, 19 boys) participated.

RESULTS

Although no sex differences for body mass index (P = 0.91) and glycosylated hemoglobin (P = 0.69) were seen, girls with type 1 diabetes had a significantly higher percent trunk fat compared with boys (P = 0.004). No sex differences were found (P > 0.05) for percent trunk fat in adolescents without diabetes. There was no sex difference among any other cardiovascular risk factors in either children with or without diabetes.

CONCLUSIONS

Female adolescents with type 1 diabetes have more centrally distributed fat, which may contribute to their relatively higher cardiovascular disease risk. Attenuation of the central distribution of fat through exercise and dietary modifications may help ameliorate their subsequent cardiovascular disease burden.

Macrovascular angiopathy in children and adolescents with type 1 diabetes

Diabetes represents one of the most common diseases globally. Worryingly, the worldwide incidence of type 1 diabetes (T1D) is rising by 3% per year. Despite the rapid increase in diabetes incidence, recent advances in diabetes treatment have been successful in decreasing morbidity and mortality from diabetes-related retinopathy, nephropathy, and neuropathy. In contrast, there is clear evidence for the lack of improvement in mortality for cardiovascular diseases (CVDs). This emphasizes the importance of focusing childhood diabetes care strategies for the prevention of CVD in adulthood. Furthermore, although most work on diabetes and macrovascular disease relates to type 2 diabetes, it has been shown that the age-adjusted relative risk of CVD in T1D far exceeds that in type 2 diabetes. As T1D appears predominantly during childhood, those with T1D are at greater risk for coronary events early in life and require lifelong medical attention. Because of the important health effects of CVDs in children and adolescents with T1D, patients, family members, and care providers should understand the interaction of T1D and cardiovascular risk. In addition, optimal cardiac care for the patient with diabetes should focus on aggressive management of traditional cardiovascular risk factors to optimize those well-recognized as well as new specific risk factors which are becoming available. Therefore, a complete characterization of the molecular mechanisms involved in the development and progression of macrovascular angiopathy is needed. Furthermore, as vascular abnormalities begin as early as in childhood, potentially modifiable risk factors should be identified at an early stage of vascular disease development.

Serum lipoprotein(a) levels are greater in female than male patients with type-2 diabetes

Women with diabetes are faced with a higher risk of dyslipidemia and cardiovascular disorders than men with diabetes. We aimed to study the role of gender and menopausal status in serum Lp(a) levels in patients with type 2 diabetes. We quantified serum Lp(a) levels in a group of 477 patients with type 2 diabetes (men, premenopausal and postmenopausal women with diabetes), as well as in 105 controls. We stratified the patients into two groups of low Lp(a) levels (Lp(a) <35 mg/dl) and elevated Lp(a) levels (Lp(a) >35 mg/dl). Patients with diabetes had higher serum Lp(a) levels than the controls. Serum Lp(a) levels was significantly higher in women with diabetes than men with diabetes. Lp(a) levels did not differ between male and females in the control group. Premenopausal and postmenopausal women with diabetes did not differ significantly in serum Lp(a) levels. The odds ratio of having a serum Lp(a) level higher than 35 was 5.85 in premenopausal women with diabetes, 5.08 in postmenopausal women with diabetes, 2.41 in men with diabetes and 1.9 in the women in the control group compared to the men in the control group, after adjustment for age and BMI. This observational study clearly indicated that serum Lp(a) levels were significantly higher in women and men with diabetes. The increase in women was independent of menopause. The level of serum Lp(a) had no correlation with lipid parameters in men or women.

Prevalence and significance of cardiometabolic risk factors in children with type 1 diabetes

Type 1 diabetes (T1D) is a common disease of childhood with a current prevalence of almost 2 cases per 1000 adolescents, according to the third National Health and Nutrition Examination Survey. Modern insulin treatment has resulted in improved quality of life for children with this chronic disorder. However, T1D continues to carry a long-term burden of increased microvascular and macrovascular complications and mortality risk. Compared to the nondiabetic population, patients with T1D are more likely to have >or=1 cardiovascular risk factor and often at an earlier age. Since the prevalence of cardiovascular risk factors increases with age in young persons with T1D, there is a clear need for early screening and counseling to prevent their occurrence and manage long-term health ramifications. The purpose of this review is to describe how traditional risk factors for cardiovascular disease such as an abnormal lipid profile, hypertension, obesity, and insulin resistance contribute to the accelerated atherosclerosis seen in young persons with T1D. A summary is given of the guidelines and recommendations published for clinical care for these patients.

Prevalence and significance of cardiometabolic risk factors in children with type 1 diabetes

Type 1 diabetes (T1D) is a common disease of childhood with a current prevalence of almost 2 cases per 1000 adolescents, according to the third National Health and Nutrition Examination Survey. Modern insulin treatment has resulted in improved quality of life for children with this chronic disorder. However, T1D continues to carry a long-term burden of increased microvascular and macrovascular complications and mortality risk. Compared to the nondiabetic population, patients with T1D are more likely to have >or=1 cardiovascular risk factor and often at an earlier age. Since the prevalence of cardiovascular risk factors increases with age in young persons with T1D, there is a clear need for early screening and counseling to prevent their occurrence and manage long-term health ramifications. The purpose of this review is to describe how traditional risk factors for cardiovascular disease such as an abnormal lipid profile, hypertension, obesity, and insulin resistance contribute to the accelerated atherosclerosis seen in young persons with T1D. A summary is given of the guidelines and recommendations published for clinical care for these patients.

Quo vadis haemapheresis. Current developments in haemapheresis

The techniques of haemapheresis originated in the development of centrifugal devices separating cells from plasma and later on plasma from cells. Subsequently membrane filtration was developed allowing for plasma-cell separation. The unspecificity of therapeutic plasma exchange led to the development of secondary plasma separation technologies being specific, semi-selective or selective such as adsorption, filtration or precipitation. In contrast on-line differential separation of cells is still under development. Whereas erythrocytapheresis, granulocytapheresis, lymphocytapheresis and stem cell apheresis are technically advanced, monocytapheresis may need further improvement. Also, indications such as erythrocytapheresis for the treatment of polycythaemia vera or photopheresis though being clinically effective and of considerable importance for an appropriate disease control are to some extent under debate as being either too costly or without sufficient understanding of the mechanism. Other forms of cell therapy are under development. Rheohaemapheresis as the most advanced technology of extracorporeal haemorheotherapy is a rapidly developing approach contributing to the treatment of microcirculatory diseases and tissue repair. Whereas the control of a considerable number of (auto-) antibody mediated diseases is beyond discussion, the indication of apheresis therapy for immune complex mediated diseases is quite often still under debate. Detoxification for artificial liver support advanced considerably during the last years, whereas conclusions on the efficacy of septicaemia treatment are debatable indeed. LDL-apheresis initiated in 1981 as immune apheresis is well established since 24 years, other semi-selective or unspecific procedures, allowing for the elimination of LDL-cholesterol among other plasma components are also being used. Correspondingly Lp(a) apheresis is available as a specific, highly efficient elimination procedure superior to techniques which also eliminate Lp(a). Quality control systems, more economical technologies as for instance by increasing automation, influencing the over-interpretation of evidence based medicine especially in patients with rare diseases without treatment alternative, more insight into the need of controlled clinical trials or alternatively improved diagnostic procedures are among others tools ways to expand the application of haemapheresis so far applied in cardiology, dermatology, haematology, immunology, nephrology, neurology, ophthalmology, otology, paediatrics, rheumatology, surgery and transfusion medicine.

Lipoprotein(a), apolipoprotein(a) polymorphism and coronary atherosclerosis severity in type 2 diabetic patients

BACKGROUND

Few and conflicting data are available in the literature on the association between Lp(a) levels and the severity of coronary artery disease (CAD) in diabetic patients. In addition, no studies took into account the role of apo(a) polymorphism. The purpose of the present study was to analyse the association of the degree of coronary atherosclerosis with Lp(a) levels and apo(a) polymorphism in a large group of type 2 diabetic patients.

METHODS

The study population consisted of 227 consecutive type 2 diabetic patients undergoing a routine coronary angiography to evaluate chest pain or suspected CAD. The patients were subdivided into four subgroups according to the number of coronary arteries diseased: normal arteries (n=26), mono-vessel disease (n=67), bi-vessel disease (n=54) and multi-vessel disease (n=80).

RESULTS

Lp(a) levels (normal arteries: 14.6+/-19.6 mg/dl; mono-vessel disease: 19.0+/-16.4 mg/dl; bi-vessel disease: 19.3+/-15.1 mg/dl; multi-vessel disease: 26.5+/-16.8 mg/dl; p<0.001) and the percentages of patients with at least one isoform of low molecular weight (normal arteries: 23.1%; mono-vessel disease: 38.8%; bi-vessel disease: 75.9%; multi-vessel disease: 81.2%; p<0.001) were significantly correlated with increasing number of coronary vessels diseased. Multiple logistic regression analysis showed that both Lp(a) levels (OR: 1.31; 95% CI: 1.02-4.11) and apo(a) polymorphism (OR: 3.43; 95% CI: 1.67-7.05) were independent predictors of CAD severity.

CONCLUSIONS

Our data suggest that Lp(a) levels and apo(a) polymorphism may be reliable predictors of CAD severity in type 2 diabetic patients.