[Metabolic syndrome: jumble syndrome of obesity or specific entity? Which treatment: diet or polypill?]

The reality of metabolic syndrome (MS) as a specific entity is debatable. However, the simple measure of waist circumference (>94 cm in men and >80 cm in women) is useful: (1) to check for insulin resistance by measuring serum levels of fasted glucose and insuline, cholesterol, triglycerides; (2) to look for diseases associated with MS such as hypertension, non alcohoolic steatohepatitis, sleep apnea, polycystic ovary disease, hypogonadism and to measure serum levels of ferritine, ALAT, ASAT, urate acid, CRP hs, testosterone and (3) to make obese people aware of their risk of becoming diabetic and to motivate them to change their life style. The utility of exercise and of various diets is discussed as well as the efficiency of drugs acting on different components of MS such as rimonabant, orlistat, metformin, glitazones, telmisartan and testosterone. The importance of political measures to fight the obesity epidemic is underlined.

The role of body position and gravity in the symptoms and treatment of various medical diseases

Postural medicine studies the effects of gravity on human body functions and the ability to influence various diseases by changing the body's position. Orthostasis requires numerous cardiovascular and neurohumoral adaptations to prevent hypotension and a resulting decrease in cerebral perfusion. Sitting upright or in a semi-sitting position reduces venous return in patients with heart failure, intracranial pressure in patients with intracranial hypertension, intraocular pressure in glaucoma patients and may decrease gastro-oesophageal reflux. A left recumbent posture also decreases reflux. A right lateral position results in a lower sympathetic tone than lying on the left side and is beneficial in patients with heart failure or after an infarction without bradycardia. A 40 to 70% decreased prevalence of the sudden infant death syndrome has been observed since the recommendation to avoid laying infants to sleep in a prone position. Sleeping in a supine posture increases the severity of sleep apnoea compared to a lateral position. In patients with acute respiratory distress syndrome, a prone position can rapidly improve blood oxygenation. Idiopathic oedema, orthostatic proteinuria, intradiscal pressure and venous circulation in legs are improved in the decubitus position, whereas arterial flow is reduced. Health risks due to microgravity and prolonged bed rest, such as osteoporosis, venous thrombosis or pressure sores, are discussed.

The role of body position and gravity in the symptoms and treatment of various medical diseases

Postural medicine studies the effects of gravity on human body functions and the ability to influence various diseases by changing the body's position. Orthostasis requires numerous cardiovascular and neurohumoral adaptations to prevent hypotension and a resulting decrease in cerebral perfusion. Sitting upright or in a semi-sitting position reduces venous return in patients with heart failure, intracranial pressure in patients with intracranial hypertension, intraocular pressure in glaucoma patients and may decrease gastro-oesophageal reflux. A left recumbent posture also decreases reflux. A right lateral position results in a lower sympathetic tone than lying on the left side and is beneficial in patients with heart failure or after an infarction without bradycardia. A 40 to 70% decreased prevalence of the sudden infant death syndrome has been observed since the recommendation to avoid laying infants to sleep in a prone position. Sleeping in a supine posture increases the severity of sleep apnoea compared to a lateral position. In patients with acute respiratory distress syndrome, a prone position can rapidly improve blood oxygenation. Idiopathic oedema, orthostatic proteinuria, intradiscal pressure and venous circulation in legs are improved in the decubitus position, whereas arterial flow is reduced. Health risks due to microgravity and prolonged bed rest, such as osteoporosis, venous thrombosis or pressure sores, are discussed.

[Adipose tissue: a real endocrine gland synthesizing hormones and cytokines: clinical implications]

Adipose tissue (AT) is not considered anymore as a passive depot for storing excess energy in the form of triglycerides but as an active organ secreting several hormones or adipokines. With the exception of adiponectin the serum levels of adipokines are increased in obesity. Leptin regulates food intake, reproductive and immune system. Adiponectin decreases insulin resistance and has antiinflammatory properties. On the contrary, resisting, tumor necrosis factor and Interleukin-6 are diabetogenic and induce inflammatory reactions. It is believed that atherosclerosis is due to the inflammation induced by oxydized LDL-cholesterol in vessels. Abdominal obesity is associated with increased incidence of metabolic disorders and insulin resistance. The role of adipokines in these disorders is described as well as their role in the antidiabetic effect of thiazo-linedinediones. AT contains also enzymes responsible for the aromatization of androstenedione into estrone, which could explain an increase of breast and uterus cancer in obese people.

[Prevention of cardiovascular and degenerative diseases: I. Aspirin, statins, or vitamins?]

Coronary syndromes are induced by atherosclerosis which results from lipid deposit as well as inflammatory cells in vascular walls triggered by oxidative modification of LDL cholesterol. Treatment with antioxidant vitamins (vitamin C and E) has no evident effect on coronary events whereas aspirin and statins treatments result in a 25 to 30% reduced rate of fatal and non fatal myocardial infarction in primary and in secondary prevention trials. Both drugs are highly recommended in secondary prevention. In primary prevention they are useful and cost effective if the estimated risk of coronary event is 1.5% per year or higher. They are not cost-effective if this risk is 0.6% per year or less. With aspirin there is a 1.5 fold increase of hemorrhagic stroke and a 2 fold increase of gastrointestinal hemorrhage. Aspirin is less efficient in younger patients (< 50 years of age), in those with high blood pressure (> 145 mmHg) and those with low serum hsCRP (< 1 mg/l.). Statins are well tolerated and they could reduce not only C-V and global mortality but also the risk of stroke and of macular degeneration. They could also delay the occurrence of diabetes and kidney failure. Folate administration can lower elevated serum homocysteine level, which is a risk factor for C-V and Alzheimer's disease. However the clinical benefit resulting from folate treatment must still be demonstrated.

[Use of brain natriuretic peptide (BNP) in the diagnosis and treatment of heart failure]

Utility of the dosage of brain natriuretic factor (BNP) in the diagnosis and treatment of heart failure. Congestive heart failure (HF) is the main reason for hospitalisation of elderly patients. HF affects nearly 15% of patients aged 75 years or older. Prognosis after the diagnosis of HF is comparable to that of cancers with 50% survival after 4 years for mild HF and 50% after one year in more severe cases. Systolic HF defined by a left ventricular ejection fraction (LVEF) < 40% is asymptomatic in half the patients. In patients with symptomatic HF, LVEF is normal in almost 50% of the cases suggesting a diastolic HF. BNP is secreted after distension of left ventricule mainly in patients with systolic or diastolic HF, in proportion to the severity of the disease. A serum level of BNP > 100 pg/ml has a sensitivity of 90 percent and a specificity of 76 percent for the diagnosis of HF. Serum BNP is also increased in kidney insufficiency and in cirrhosis. BNP increase has a prognostic value to predict mortality after cardiac failure or myocardial infarction. Except for digoxin, all the drugs used to treat HF decrease serum levels of BNP. In dyspneic patients, serum levels of BNP < 50 pg/ml can exclude HF with a good probability. However BNP determination is not useful to diagnose HF in a general population.

[High-sensitivity C-reactive protein: a new risk factor of coronary disease]

CRP is an acute-phase protein released after an infection or an inflammation. Atherosclerosis is actually believed to result from the combination of lipid deposits in the arterial wall together with inflammatory cells. Numerous prospective studies have shown that the serum level of CRPhs is a strong predictor of future coronary events. The risk of such events is twice as high in patients with mean CRPhs values of 2.4 mg/l than in patients with values of 1 mg/l. Serum levels of CRPhs have been measured in 265 of our patients with normal sedimentation rate. Mean levels were 1.5 + 1.5 mg/l in men and 1.64 + 1.5 mg/l in women. Levels were higher in obese and diabetic patients. CRP levels can be slightly increased in arthritis. Serum levels double in women treated by oral estrogens after menopause. CRP should be measured at least 4 weeks after an infection such as a viral rhinitis. CRP levels decrease by 15 to 30% after treatment with glitazone (rosiglitazone) and with statins. The effect of aspirin is controversial. The magnitude of the preventive effect of aspirin and of statins on coronary risks could depend on the basal level of CRPhs. If these data are confirmed, it would be easier to select those patients who would be the most likely to benefit from the antiinflammatory treatments.