Lipoprotein(a) levels and apolipoprotein(a) polymorphism in type 1 diabetes mellitus: relationships to microvascular and neurological complications

Role of structured individual patient education in the prevention of vascular complications in newly diagnosed type 2 diabetes: the INdividual Therapeutic Education in Newly Diagnosed type 2 diabetes (INTEND) randomized controlled trial

OBJECTIVE

Recent studies showed that a structured patient therapeutic education (PTE) may decrease both mortality and the development of diabetes complications. Nevertheless, no data are available in the literature on the impact of individual PTE on the complications in newly diagnosed type 2 diabetic patients. Aim of the present randomized controlled trial is to evaluate the impact of individual PTE on the occurrence of macrovascular complications in newly diagnosed type 2 diabetic patients when compared to usual care (UC) and group PTE.

DESIGN AND METHODS

Six hundred newly diagnosed type 2 diabetic patients will be enrolled. The patients will be randomly assigned to one of these three groups: individual PTE, group PTE and UC. A comprehensive and complete PTE will be delivered to all the patients: PTE will include eleven themes. Primary composite endpoint of the study is occurrence of vascular complications, including cardiovascular death, non fatal coronary disease, non fatal stroke, peripheral artery disease. Secondary endpoints are: foot ulcers, amputations, sexual dysfunction, quality of life, microvascular complications, bone health, intensification of diabetes and hypertension therapy.

RESULTS AND CONCLUSIONS

The present trial can give precious information on the features for the most effective PTE.

Total Serum Cholesterol Increases Risk for Development and Progression of Nonproliferative Retinopathy in Patients with Type 1 Diabetes Without Therapeutic Intervention: Prospective, Observational Study

INTRODUCTION

Results from studies investigating relationship between serum lipids and risk of development and progression of diabetic retinopathy (DR) in patients with type 1 diabetes (T1DM) are not consistent. The objective of this study was to explore the relationship between serum lipids and risk of development and progression of nonproliferative diabetic retinopathy (NPDR) in T1DM with normal renal function and with no therapeutic intervention that might influence on retinopathy and serum lipids status.

METHODS

A total of 103 T1DM with normal renal function (urinary albumin excretion rate <30 mg/24 h, estimated glomerular filtration rate (eGFR) >60 mL min^‒11.73m^‒2), and before any interventions with lipid-lowering therapy, ACE inhibitors or angiotensin II receptor blockers were included in this study and followed for 41 months. Photodocumented retinopathy status was made according to the EURODIAB protocol.

RESULTS

Patients who developed NPDR or progressed to proliferative retinopathy were older (44 vs. 33 years, p <0.001), had longer duration of diabetes (21.1 vs. 13.3 years, p <0.001), and higher serum total cholesterol level (5.1 vs. 4.5 mM/L, p = 0.02) compared to patients without retinopathy. In a backward stepwise Cox's multiple regression analysis serum total cholesterol was significantly associated with risk of development or progression of NPDR in our subjects (p = 0.04), with odds ratios of 1.27-1.91.

CONCLUSION

These data suggest that serum total cholesterol levels are associated with risk of development and progression of NPDR in T1DM and normal renal function. The study was conducted in patients with no therapeutic interventions.

Lipoprotein(a) serum levels in diabetic patients with retinopathy

BACKGROUND

Atherogenic lipoproteins, such as total cholesterol, LDL cholesterol, oxidized low density lipoprotein, and triglycerides, are associated with progression of retinopathy. Aim. To evaluate the relationship between lipoprotein(a) and retinopathy in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

We enrolled 145 diabetic consecutive patients (82 females, 63 males; mean age 66.8 ± 12 years, mean duration of diabetes 9.4 ± 6.8 years). Presence and severity of retinopathy were evaluated. Serum lipid profile, including Lp(a) level, was assessed.

RESULTS

High Lp(a) levels have been observed in 54 (78.3%) subjects and normal levels in 13 (18.85%) subjects as regards diabetic patients with retinopathy. Lp(a) levels were high in 15 subjects (21.75%) and normal in 63 subjects (91.35%) as regards patients without retinopathy.

CONCLUSIONS

Lp(a) levels are increased in a significant percentage of patients with retinopathy compared to diabetic patients without retinopathy. The impact of Lp(a) levels on diabetic retinopathy needs to be further investigated.

Lipoprotein(a) and homocysteine as genetic risk factors for vascular and neuropathic diabetic foot in type 2 diabetes mellitus

Neuropathy and peripheral artery disease represent the main pathophysiological conditions underlying diabetic foot. Several studies showed that Lipoprotein(a)-Lp(a)-and homocysteine (Hcy) can be associated with diabetic complications, but their relationship with diabetic foot is unclear. Aim of this study was to investigate whether Lp(a) and Hcy were associated with diabetic foot ulcerations, classified according to the presence of peripheral artery disease (PAD) or neuropathy. From among consecutive type 2 diabetic attending at the Diabetic Foot Clinic 27 subjects with vascular diabetic foot (VDF), 43 with neuropathic diabetic foot (NDF) and 52 controls without foot ulceration, neuropathy, and PAD were enrolled. Both Lp(a) (26.1 ± 22.7 vs. 14.9 ± 19.5 mg/dl; P = 0.003) and Hcy levels (15.4 ± 5.7 vs. 12.2 ± 5.1 μmol/l; P = 0.022) were significantly greater in the VDF group than in controls. Lp(a) levels were significantly lower in the NDF group than in controls (6.9 ± 8.1 versus 14.9 ± 19.5 mg/dl; P = 0.009), while no difference in Hcy levels was found. Multiple logistic regression analysis showed that Hcy was associated with VDF (OR: 1.11; 95% CI: 1.07-14.1; P = 0.048). Lp(a) did not enter the model, but its P-value was very near to the significant level (OR: 1.09; 95% CI: 0.99-12.05; P = 0.059). Moreover, low Lp(a) levels were associated with NDF (OR: 0.84; 95% CI: 0.21-0.96; P = 0.039). Our study has shown for the first time that high Lp(a) and Hcy levels are associated with the development of VDF, while low Lp(a) levels appear to be associated with delayed wound healing in patients with neuropathic foot ulcerations.

Lipids and lipoprotein(a) concentrations in Tunisian type 2 diabetic patients; Relationship to glycemic control and coronary heart disease

The aim of this study was to evaluate plasma lipoprotein(a) [Lp(a)] concentrations in Tunisian patients with type 2 diabetes mellitus (DM), to correlate the values with other lipid parameters, and to examine the relationship to glycemic control and coronary heart disease (CHD). Diabetic patients with and without CHD (n=200) had significantly higher levels of Lp(a) (327.94+/-239.93 mg/l) and a greater proportion of elevated (>300 mg/l) Lp(a) concentrations (46%) compared with 100 healthy nondiabetic controls (269.83+/-225.6 mg/l, P<.01, and 26%, P<.01), while there were no statistically significant difference between diabetics without CHD (n=100) and controls. No significant association of Lp(a) with glycemic control (HbAlc or fasting blood glucose) was noted in diabetic patients. Positive correlations were observed between Lp(a) levels and total cholesterol and LDL-C in all diabetic patients and particularly in diabetic men. Male patients with CHD showed significantly higher plasma Lp(a) levels than those without CHD (P=.023), and 57.3% of patients with CHD showed increase (>300 mg/l) Lp(a) compared with 33.3% of patients without CHD. Elevated levels of Lp (a) and abnormal lipid profile in diabetic men suggest their involvement in atherogenesis and subsequent development of CHD.

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

OBJECTIVES

To determine whether apo(a) isoforms and plasma Lp(a) concentrations in association with some lipid parameters increase the relative risk for the development of atherosclerosis in patients with diabetes mellitus (IDDM and NIDDM).

DESIGN AND METHODS

Apo (a) isoforms, Lp(a) and plasma lipids were determined in 40 IDDM and 65 NIDDM patients and in 182 healthy individuals. Apo(a) isoforms were separated by 3 to 15% gradient SDS-PAGE followed by immunoblotting.

RESULTS

Logistical analysis showed that: Lp(a) levels >30 mg/dL (RR = 0.25, p < 0.000001; RR = 0.18, p < 0.00002), HTA (RR = 0.212, p < 0.00001; RR = 0.30, p < 0.00001), LMW-S1 apo(a) isoform (RR = 6.86, p < 0.0131; RR = 7.04, p < 0.0057) play a significant role in aterogenecity in both groups of patients with DM (IDDM and NIDDM). The 6.50-fold increase in risk was found in NIDDM patients with high Lp(a) levels (>30 mg/dL) and plasma total/HDL cholesterol ratio (4.5-5.8).

CONCLUSION

Elevated Lp(a) levels, LMW S1 apo(a) isoform, HTA and combination of increased Lp(a) levels and total/HDL cholesterol ratio increase the risk for the development of atherosclerosis in patients with DM (IDDM and NIDDM).

Relation of apolipoprotein (a) phenotypes to diabetic retinopathy in elderly type 2 diabetes

The aim of this study was to clarify the relationship between apolipoprotein (a) (apo (a) ) phenotypes and diabetic retinopathy in elderly type 2 diabetes. Serum Lp (a) concentrations and apo (a) phenotypes were analyzed in 250 diabetic patients aged 60 to 88 years old. Apo (a) phenotypes were classified into 7 subtypes (F, B, S1, S2, S3, S4, O (Null) ) by the method SDS electrophoresis with Western blotting. Patients were divided into two groups according to their apo (a) phenotypes:a low molecular weight (LMW) Lp (a) group, and a high molecular weight (HML) Lp (a) group. Patients were classified as having one of 4 types of diabetic retinopathy: no retinopathy (R0), simple retinopathy (R1), pre-proliferative retinopathy (R2), and proliferative retinopathy (R3). There was a significant association between serum Lp (a) levels and severity of diabetic retinopathy (p<0.001). A gradual trend toward increasing serum Lp (a) levels was observed across the groups (from R0 to R3). A significantly greater percentage of LMW Lp (a) was observed in the R1, R2, and R3 groups than in the R0 group (42.9% (p<0.001), 27.0% (p<0.01), and 27.3% (p<0.05) vs. 10.4%). Multiple logistic regression analysis revealed that duration of diabetes and LMW Lp (a) are independent risk factors for diabetic retinopathy. These results provide significant evidence that LMW Lp (a) contributes to an increased risk of diabetic retinopathy in elderly type 2 diabetes.

Serum lipoprotein(a) concentration as a cardiovascular risk factor in Kuwaiti type 2 diabetic patients

Serum lipoprotein(a) [Lp(a)], a risk factor for coronary heart disease (CHD) in some nondiabetic populations, is largely under genetic control and varies among ethnic and racial groups. We evaluated serum Lp(a) concentration and its relationship with traditional CHD risk factors (age, sex, smoking, hypertension, dyslipidemia) as well as stage of diabetic nephropathy in 345 type 2 diabetic patients. Lp(a) concentration was skewed with median (2.5th, 97.5th percentiles) of 25.0 (8.1, 75.7) mg/dl. Twenty-three of 55 (41.8%) patients with CHD had increased (>30 mg/dl) Lp(a) compared with 102 of 290 (35.1%) patients without CHD (P=.35). Twelve of 27 (44.4%) female patients with CHD had increased Lp(a) compared to 11 of 28 (39.3%) males (P=.70). Lp(a) was significantly (P<.05) higher in females than males, but the logistic regression analysis showed significant association of Lp(a), LDL-C, and duration of diabetes mellitus (DM) with CHD in male patients only. Although female patients with CHD and macroalbuminuria had significantly (P<.05) higher Lp(a) than normoalbuminuric female patients without CHD, no such association was found in males and no significant association was found between Lp(a) and the degree of albuminuria. Partial correlation analysis controlling for age, sex, and BMI showed significant correlation of Lp(a) with total cholesterol only (P=.03) and no correlation was found with other lipid parameters. Multiple regression analysis did not show significant associations of Lp(a) with standard CHD risk factors, HbA(1c), and plasma creatinine. This study is in agreement with studies in other populations, which showed that Lp(a) may not be an independent risk factor for CHD in patients with DM. However, as Lp(a) could promote atherogenesis via several mechanisms, follow-up studies in our patients will confirm if increased Lp(a) concentration can partly account for the poorer prognosis when diabetic patients develop CHD.

Association of lipoprotein(a) levels and apolipoprotein(a) phenotypes with coronary artery disease in Type 2 diabetic patients and in non-diabetic subjects

AIMS

We investigated whether in Type 2 diabetic patients lipoprotein(a) (Lp(a)) levels and apolipoprotein(a) (apo(a)) polymorphism are associated with angiographically documented coronary artery disease (CAD). We also examined whether there are differences in the distributions of Lp(a) levels and apo(a) phenotypes between CAD patients with and without diabetes.

METHODS

A hundred and seven diabetic patients with CAD, 274 diabetic patients without CAD, 201 non-diabetic patients with CAD, and 358 controls were enrolled.

RESULTS

Diabetic patients with CAD showed Lp(a) levels (21.2 +/- 17.7 vs. 15.1 +/- 17.8 mg/dl; P = 0.0018) and a percentage of subjects with at least one apo(a) isoform of low molecular weight (MW) (67.2% vs. 27.7%; P = 0.0000) significantly greater than diabetic patients without CAD. Multivariate analysis showed that in diabetic patients Lp(a) levels and apo(a) phenotypes were significantly associated with CAD; odds ratios (ORs) of high Lp(a) levels for CAD were 2.17 (1.28-3.66), while ORs of the presence of at least one apo(a) isoform of low MW were 5.35 (3.30-8.60). Lp(a) levels (30.2 +/- 23.7 vs. 21.2 +/- 17.7 mg/dl; P = 0.0005) and the percentage of subjects with at least one apo(a) isoform of low MW (87.0% vs. 67.2%; P = 0.0001) were significantly higher in CAD patients without than in those with diabetes.

CONCLUSIONS

Our data suggest that Lp(a) levels and apo(a) phenotypes are independently associated with CAD in Type 2 diabetic patients; thus both these parameters may be helpful in selecting diabetic subjects at high genetic cardiovascular risk. However, Lp(a) levels and apo(a) polymorphism seem to be cardiovascular risk factors less important in diabetic than in non-diabetic subjects. Diabet. Med. 18, 589-594 (2001)