Giancarlo Descovich

Atherosclerosis and Cardiovascular Diseases

Lipoprotein(a) [Lp(a)] plays an important role in atherosclerosis. The biological effects of Lp(a) have been attributed either to apolipoprotein(a) or to its low-density lipoprotein-like particle. Lp(a) contains platelet-activating factor acetylhydrolase, an enzyme that exhibits a Ca -independent phospholipase A2 activity and is complexed to lipoproteins in plasma; thus, it is also referred to as lipoprotein-associated phospholipase A2. Substrates for lipoprotein-associated phospholipase A2 include phospholipids containing oxidatively fragmented residues at the sn-2 position (oxidized phospholipids; OxPLs). OxPLs may play important roles in vascular inflammation and atherosclerosis. Plasma levels of OxPLs present on apolipoprotein B-100 particles (OxPL/apolipoprotein B) are correlated with coronary artery, carotid, and peripheral arterial disease. Furthermore, OxPL/apolipoprotein B levels in plasma are strongly correlated with Lp(a) levels, are preferentially sequestered on Lp(a), and thus are potentially subjected to degradation by the Lp(a)-associated lipoprotein-associated phospholipase A2. The present review article focuses specifically on the characteristics of the lipoprotein-associated phospholipase A2 associated with Lp(a) and discusses the possible role of this enzyme in view of emerging data showing that OxPLs in plasma are preferentially sequestered on Lp(a) and may significantly contribute to the increased atherogenicity of this lipoprotein. (Arterioscler Thromb Vasc Biol. 2007;27:2094-2099.)

MULTICENTRE STUDY OF SOYBEAN PROTEIN DIET FOR OUTPATIENT HYPERCHOLESTEROLÆMIC PATIENTS

The animal proteins in a low-lipid, low-cholesterol diet were substituted with a textured soybean preparation for 127 outpatients with stable type II hyperlipoproteinaemia selected from eight Italian and one Swiss lipid clinics. Eight weeks of the modified diet reduced plasma cholesterol by 23.1% in the 67 participating male patients and by 25.3% in the 60 females. No significant changes in plasma triglycerides, high-density lipoprotein cholesterol, and body weight were recorded. Better reductions in plasma cholesterol occurred in non-familial cases and in very young male patients. The acceptable taste of the soybean preparation used in this study, and its easy handling, indicate that this type of dietary treatment may be suitable for outpatients.

Controlled evaluation of pantethine, a natural hypolipidemic compound, in patients with different forms of hyperlipoproteinemia☆

Pantethine (P), the stable disulphate form of pantetheine, major component and precursor of coenzyme A, was evaluated within a double-blind protocol (8 weeks for P or for a corresponding placebo) in 29 patients, 11 with type IIB hyperlipoproteinemia, 15 with type IV, and 3 with an isolated reduction of high density lipoprotein cholesterol (HDL-C) levels. In type IIB patients, P (300 mg t.i.d.) determined a highly significant lowering of plasma total and low density lipoprotein (LDL) associated cholesterol (-13.5% for both parameters). In the same patients, HDL-C levels increased about 10% at the end of treatment. Switching from P to placebo was associated with a rapid return to the baseline cholesterolemia. Both in type IIB and type IV patients, plasma triglyceride levels were reduced around 30%, when P was given as the first treatment; when it was preceded by placebo, reductions were less striking (respectively, -17.8% for type IIB and -13.0% for type IV, at the end of P treatment). HDL-C levels were not increased by P, either in type IV, and in the patients with low HDL cholesterolemia. In type IV, LDL cholesterol levels showed a variable response to P: they tended to increase when below 132 mg/dl, prior to treatment, and to be reduced when above this level. This study provides evidence for a significant hypocholesterolemic effect of P, a natural compound free of overt side effects. It also indicates that P may raise HDL-C levels in type IIB patients, while moderately reducing triglyceridemia.

Reduced triglyceridemia and increased high density lipoprotein cholesterol levels after treatment with acipimox, anew inhibitor of lipolysis

Acipimox (5-methylpyrazine carboxylic acid 4-oxide) is a new inhibitor of lipolysis with long-lasting activity, whose plasma lipid lowering potential was demonstrated in early clinical trials. The hypolipidemic effect of acipimox was investigated in two double-blind cross-over trials versus placebo. The first trial, carried out in 12 type IV patients, showed a significant triglyceride lowering effect (-35%) following 4 weeks of drug administration at a 250 tid dose. The same regimen, maintained for 9 weeks in 18 type IIA patients, failed to induce a significant reduction of total cholesterolemia. However, in 10 subjects, in whom lipoprotein cholesterol fractionation was carried out, a significant reduction of low density and highly significant increase in high density lipoprotein cholesterol levels (respectively -11% and +20%) were observed.

Double-blind multicenter trial on a new medium molecular weight glycosaminoglycan. Current therapeutic effects and perspectives for clinical use.

The ability of glycosaminoglycans to bind to a wide number of biologically active macromolecules has already been investigated. Recent clinical trials on the possible therapeutic benefits of glycosaminoglycans must be placed in perspective, even if they appear to be particularly encouraging, especially as regards the glycosaminoglycan effects on certain coagulation factors. A multicenter, medium-term, double-blind, crossover trial was performed by several Italian Lipid Clinics to determine whether administration of a medium molecular weight glycosaminoglycan (Sulodexide) has a significant clinical effect. Patients affected by peripheral vascular disease and/or hyperlipidemia (type IIa, IIb and IV) were submitted to a 4-week wash-out period, followed by parenteral Sulodexide (S) or placebo (P) administration for 2 weeks, another 2 week wash-out period, parenteral crossover drug or P administration for 2 weeks and, finally, oral S administration for 6 months. Sulodexide lowered plasma viscosity and plasma fibrinogen in all patients. There was also a drop in triglycerides together with a rise in apo A-I and HDL-C in type IV hyperlipoproteinemics, whereas there was no significant effect on total or LDL-plasma cholesterol in type IIa and IIb patients. Moreover, there was a percent increase in peak flow and rest flow in the lower limbs of peripheral vascular disease patients. No side effects or intolerance phenomena were detected. The results indicate that Sulodexide administration may be useful in long-term treatment of patients with peripheral vascular disease and a concomitant increase in plasma triglycerides and/or fibrinogen and/or viscosity.

Plasma lipoprotein(a) concentration in familial hypercholesterolemic patients without coronary artery disease

Familial Hypercholesterolemia (FH) is a condition characterized by markedly elevated blood cholesterol, low-density lipoproteins (LDL), and apolipoprotein B-100 (apo B). The molecular basis of this monogenic disease is the defective functioning of the cellular receptor for LDL that recognizes apo B. Lipoprotein(a) [Lp(a)] is a circulating lipoprotein that is structurally related to LDL, as it also contains apo B. To assess the impact of the LDL receptor deficiency on the plasma Lp(a) concentration, we measured Lp(a) in 28 FH patients and in 31 unaffected relatives. Because elevation of Lp(a) concentration in plasma of patients with coronary artery disease (CAD) appears to occur independently from plasma cholesterol levels, to avoid potentially confounding problems, members of the families chosen had no history for the disease. Whereas apo B clearly showed a bimodality of distribution by being significantly higher in the FH patients (166 +/- 38 mg/dL) than in the unaffected relatives (92 +/- 18 mg/dL), Lp(a) concentration did not differ in the two groups of patients (30 +/- 24 mg/dL in the FH patients v 31 +/- 23 in the normolipidemic relatives). Similar results were obtained when only siblings were further considered. We conclude that although Lp(a) is closely related to LDL structurally, its level in plasma is not significantly affected by the LDL receptor activity.

Nutritional characteristics of a rural Southern Italy population: the Ventimiglia di Sicilia Project.

Objective: Knowledge of alimentary habits among populations permits a better definition of appropriate public health interventions. We designed the epidemiological project “Ventimiglia di Sicilia” to characterize the risk profile in a rural village with low total cholesterol levels and low early cardiovascular mortality but with a large prevalence of overweight and obesity, which previously have been significantly associated with total mortality. Methods: 488 individuals of age 20 to 69 years were included in the dietary survey conducted by a seven-day food record. Results: Alimentary habits were characterized by high consumption of total and complex carbohydrates (respectively 52.5 ± 7.6% and 46.6 ± 8.2% of daily energy) and by a low cholesterol intake (92.5 ± 35.0 mg/1000 kcal/day). Fat intake was 34.7 ± 7.7% of daily energy due to a higher consumption of monounsaturated fats in respect to saturated fats (respectively 20.5 ± 5.1% and 10.2 ± 2.9% of daily energy). In particular, in this population there was a large consumption of bread, pasta, fresh vegetables, olive oil and fruits. We also observed an excess of total calories (about 2900 kcal/day in men and 2100 kcal/day in women) not balanced by a high degree of physical activity levels. Furthermore we found a significant higher total and saturated fat consumption in the youngest individuals and in people with higher educational levels. Conclusions: Dietary habits of Ventimiglia di Sicilia still follow the nutritional characteristics typical of the Mediterranean diet. The high total calorie intake indicates a quantitative more than qualitative problem, which may account the large prevalence of overweight and obesity and may represent a public health issue that needs to be corrected in such a rural population.

Cardiovascular lesions in chronic pancreatitis

We prospectively investigated fifty-four consecutive patients with proven chronic pancreatitis and 54 control subjects for the presence of cardiovascular lesions. Clinical and laboratory evidence of arterial involvement was found in 18 patients (33%) and in five controls (9%) (P<0.01). Electrocardiographic alterations indicating coronary heart disease were found in eight patients and in three controls, and peripheral symptoms and signs indicating obliterative atherosclerotic disease of the lower extremities were found in 12 patients (two had associated electrocardiographic changes) and in two controls. No significant differences in the prevalence of the major vascular risk factors were observed between patients with vascular lesions and those without, and between patients and control subjects. It is concluded that patients with chronic pancreatitis have more frequent cardiovascular lesions which tend to develop at an earlier age, compared to the general population. The possibility that chronic pancreatitis may favor the development of these lesions is discussed.

BLOOD LIPIDS IN ITALY * Regional Differences

Serum cholesterol and triglyceride levels have been evaluated in samples from fasting males aged 20--59 in Northern (Brisighella), Central (Rome) and Southern (Pozzuoli) Italy. Regularly performed quality controls between laboratories assured comparability of data. A statisitically significant difference of mean serum cholesterol and triglyceride levels was observed for most age-groups in the 3 different areas, lower values being found in the southern population as compared to the central and northern ones. These results support previous findings and the thesis that large differences in blood lipid levels may still exist even within the same country and that they at least in part may be culturally determined in connection with different dietary habits.

From observational to intervention programmes. The Brisighella study

The past target of epidemiology concerned the study of chronic degenerative/proliferative diseases, with the aim of detecting and evaluating some suspected etiological and/or risk factors (RF).