OSAS and metabolic diseases: Round Table, 99(th) SIO National Congress, Bari 2012.

This draft of the Official Round Table held during the 99th SIO National Congress is an updated review on the diagnostic tools, the importance of polysomnographic recording and a critical analysis of the surgical techniques in obstructive sleep apnoea syndrome (OSAS). The review and analysis of available publications is the premise along with a specific analysis of the relationship between OSAS and metabolic and vascular disorders. In addition, the most recent investigations on sleep disorders and altered glucose metabolism are summarised and discussed together with the results of a study by the authors involving a fairly large number of patients with OSAS and diabetes.

[Clinical evaluation of a selective inhibitor of cholesterol synthesis: pravastatin]. / Valutazione clinica di un inibitore selettivo della sintesi del colesterolo: la pravastatina.

The recent introduction in clinical practice of a new class of drugs able to reduce the endogenous synthesis of cholesterol has undoubtedly made a noteworthy contribution to the treatment of hypercholesterolaemia which, as is well known, is one of the greatest risk factors in the natural history of atherosclerotic disease and of its cardiovascular complications. A last generation drug belonging to this family is pravastatin which differs from the other substances inhibiting the activity of the key enzyme of cholesterol metabolism, HMGCaA reductase, because of certain features of the molecule, such as hydrophilia and the fact it is already pharmacologically active at the moment of oral administration. Pravastatin, which is probably a special category of HMGCoA reductase inhibitor, has shown, in numerous experimental studies and controlled clinical trials, a notable effectiveness in reducing in a highly selective fashion the synthesis of cholesterol in the liver cells and consequently the number of cholesterol-rich lipoproteins in the systemic circulation, without also determining significant biologically negative side-effects.

High density lipoprotein cholesterol low serum level as the only risk factor in male patients with coronary heart disease.

Forty-three male patients with myocardial infarction, severe angiographic coronary lesions, high or normal low density lipoprotein (LDL) cholesterol serum levels, and without other risk factors for coronary heart disease were selected. In all patients high density lipoprotein (HDL) cholesterol and HDL-cholesterol/total cholesterol ratio were significantly lower than in the control group; in particular, the ratio was below 0.240 which was the median value of normal subjects. Six patients with total cholesterol and LDL-cholesterol below 5.16 and 3.35 mmol/l respectively, had low serum levels of HDL-cholesterol; in 4 of them the value of this risk factor was below 0.9 mmol/l; 2 of 6 patients had a lipoprotein (a) serum concentration above 0.3 g/l but not a premature myocardial infarction or a clinical history of coronary heart disease. Our data confirm that HDL-cholesterol/total cholesterol ratio could be a better marker of coronary heart disease than HDL-cholesterol, total cholesterol or LDL-cholesterol and suggest the importance to check HDL-cholesterol serum levels also in subjects without risk factors for atherosclerotic disease.

[Hypercholesterolemia: therapeutic approach]. / Ipercolesterolemia: l'approccio terapeutico.

Epidemiological observations, experimental and clinical researches have laid special stress on the importance of hypercholesterolemia in the natural development of the atherosclerotic disease and its cardiovascular complications. Primary and secondary trials have demonstrated the benefits of cholesterol-lowering therapy to modify the evolution of atherosclerotic disease. In particular, it was observed a significant reduction of incidence and mortality due to coronary heart disease, that is the most common complication of atherosclerosis. At the present time, we have a new class of cholesterol-lowering drugs which is able to inhibit the 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase, the enzyme limiting the endogenous pathway of cholesterol synthesis. The HMGCoA reductase inhibitors, according to the chemical structure, can be divided into two groups. The first includes inactive lactone prodrugs, as Lovastatin and Simvastatin, that are enzymatically hydrolyzed to the corresponding ring-opened active forms in the liver, where the HMGCoA reductase inhibitors must chiefly reduce cholesterol synthesis. To the other group belongs the Pravastatin, a drug that is administered in its active open hydroxyacid form. Several clinical studies seem to demonstrate a greater cholesterol-lowering effect of the active form of Simvastatin, probably because of its more affinity for the HMGCoA reductase enzyme. Up to now, no inhibitor of HMGCoA reductase has showed serious toxic effects in man. The remarkable therapeutic efficacy showed by Simvastatin to reduce the serum concentrations of total and LDL-cholesterol, associated with moderate side-effects, ascribes to this molecule an important role in the therapeutic approach of familial and polygenic hypercholesterolemia.

[Effects of simvastatin on atherogenic blood lipid pattern]. / Effetti della simvastatina sul pattern lipidemico aterogeno.

The effect of a 6-month treatment with simvastatin, an HMG CoA-reductase inhibitor, on serum lipoprotein pattern was investigated in patients affected by primary hypercholesterolemia. After 4-6 weeks of lipid lowering diet, 46 patients showing serum cholesterol greater than 250 mg/dl and triglycerides less than 200 mg/dl were included in the study and treated with simvastatin (10-30 mg/day) plus diet. Serum total cholesterol, LDL-cholesterol, apolipoprotein B and triglycerides levels significantly decreased at the end of the follow-up (-27%, -33%, -22%, -26% respectively). Apolipoprotein A1 showed a significant increase as well as HDL-cholesterol, HDL3-cholesterol and apolipoprotein A1/B ratio. This study provides further findings on the simvastatin efficacy to normalize the lipoprotein pattern in primary hypercholesterolemia.

Are low levels of HDL2-cholesterol a risk factor for atherosclerosis of cerebral vascular disease? Case report.

A case of a 45 years old man with an atherosclerotic stenosis of right internal carotid and TIA event is reported. The patient showed an increase of total cholesterol and LDL-cholesterol serum levels and, in particular, a very low familiar HDL2-cholesterol serum value. The possibility that this last condition could represent an important co-factor of the extracranial cerebrovascular disease is discussed. The usefulness of a long-term follow-up of all family members, showing the same lipids pattern, is also suggested.