Uric acid and uric acid/creatinine ratio and their correlations with the hemorheological determinants in subjects with subclinical carotid atherosclerosis.

BACKGROUND AND OBJECTIVE: we have examined the concentration of serum uric acid and the serum uric acid/creatinine ratio as well as their correlations with the main determinants of the hemorheological profile in a group of subjects with subclinical carotid atherosclerosis. METHODS: we evaluated the concentration of serum uric acid and the serum uric acid/creatine ratio in 43 men and 57 women [median age 66.00 (25)] with subclinical carotid atherosclerosis, subsequently divided according to the number of traditional cardiovascular risk factors and to the insulin resistance degree. RESULTS: serum uric acid, but not the serum uric acid/creatinine ratio, results strongly influenced by the number of cardiovascular risk factors and by the insulin resistance degree. In the whole group and in the subgroups of subclinical carotid atherosclerosis subjects, serum uric acid and serum uric acid/creatinine ratio show significant correlation, besides with whole blood viscosity, with plasma viscosity and erythrocyte aggregation. The influence of the serum uric acid on the erythrocyte aggregability that is a part of the erythrocyte aggregation is to ascribe to the action carried out by serum uric acid on the erythrocyte zeta potential. CONCLUSIONS: it is reasonable to think that the treatment of the asymptomatic or symptomatic hyperuricemia with the urate-lowering therapy that reduces the serum uric acid concentration may reflect on the hemorheological profile which role on the atherosclerotic cardiovascular disease is well known.

The function of matrix metalloproteinase-9 (MMP-9) and its tissue inhibitor (TIMP-1) in several clinical conditions: Results and analysis of our survey.

The goal of this research was to evaluate the plasma concentration of MMP-9 and its tissue inhibitor (TIMP-1) in different clinical conditions. It included several groups of subjects: 31 overweight subjects; 91 obese adults divided into two subgroups according to the BMI value (BMI 30-35 Kg/m2 and BMI > 35 Kg/m2); 90 subjects with metabolic syndrome (MS) divided into two subgroups (with and without diabetes mellitus); 100 subjects with preclinical carotid atherosclerosis (PCA) divided according to the number of cardiovascular risk factors and to the insulin resistance degree; 48 subjects with obstructive sleep apnoea syndrome (OSAS) divided according to the apnoea/hypopnea index (AHI); 27 subjects with chronic kidney disease (CKD) on conservative management; 31 subjects with CKD on regular haemodialysis treatment. We have found a significant increase of MMP-9 and TIMP-1 in overweight subjects, in obese adult and in MS subjects. In obese adults, the behaviour of these two parameters was not influenced by the degree of obesity, while in the group of MS subjects both these parameters were clearly influenced by the presence of diabetes mellitus. In subjects with PCA, we observed an increase of MMP-9 associated with a significant decrease of TIMP-1; the same trend was found by subdividing the entire group in accordance with the number of cardiovascular risk factors and with the insulin resistance degree. In subjects with OSAS, we noted an increase in MMP-9 and TIMP-1; this increase was more evident in subjects with OSAS having AHI > 30. In individuals with CKD on conservative and haemodialysis treatment we have found, at baseline, a marked increase in MMP-9 and a significant decrease of TIMP-1. In dialyzed subjects, after a standard dialysis session was noted, a significant increase in MMP-9 was associated with a further decrease in TIMP-1.

Lipid Peroxidation, Protein Oxidation, Gelatinases, and Their Inhibitors in a Group of Adults with Obesity.

The association between obesity and cardiovascular diseases has a multifactorial pathogenesis, including the synthesis of inflammatory molecules, the increase in oxidative stress and the dysregulation of the matrix metalloprotease (MMP) concentration and activity. In a group of adults with obesity, divided in 2 subgroups according to the body mass index (BMI), we examined lipid peroxidation, expressed as thiobarbituric acid-reactive substances (TBARS), protein oxidation, expressed as protein carbonyl groups (PCs), plasma gelatinases (MMP-2 and MMP-9), and their tissue inhibitors (TIMP-1 and TIMP-2). In the whole group, as well as in the 2 subgroups (with BMI 30-35 or BMI>35) of obese subjects, we observed an increase in TBARS, PCs, MMP-2, and MMP-9, and also TIMP-1 and TIMP-2 in comparison with the control group. A positive correlation between TBARS and PCs emerged in obese subjects and persisted after dividing obese subjects according to BMI. The correlation between MMP-2 and TIMP-2 was not statistically significant, while a significant correlation was present between MMP-9 and TIMP-1. The correlations between the markers of oxidative stress (TBARS and PCs) and those of the MMP/TIMP profile indicated a more marked influence of protein oxidation on MMPs and TIMPs in comparison with TBARS. The innovative aspect of our study was the simultaneous evaluation of oxidative stress markers and MMP/TIMP profile in adult obese subjects. We observed significant alterations and correlations that may negatively influence the clinical course of the disease.

Analysis of the Blood Viscosity Behavior in the Sicilian Study on Juvenile Myocardial Infarction.

Considering the role of hemorheology in coronary circulation, we studied blood viscosity in patients with juvenile myocardial infarction. We examined whole blood viscosity at high shear rate using the cone-on-plate viscosimeter Wells-Brookfield ½ LVT and at low shear rate employing a viscometer Contraves LS30 in 120 patients (aged <46 years) with myocardial infarction, at the initial stage and subsequently 3 and 12 months after. At the initial stage, patients had an increased whole blood viscosity in comparison to normal controls. This hemorheological profile was not influenced by the cardiovascular risk factors, nor by the extent of coronary lesions, even if some differences were evident between patients with ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI). The blood viscosity pattern at the initial stage did not influence recurring ischemic events or the onset of heart failure during an 18 months' follow-up. The neutrophil to lymphocyte ratio did not affect the blood viscosity pattern. We reevaluated 83 patients 3 months after and 70 patients 12 months after the acute coronary syndrome, and we found that the hemorheological parameters were still altered in comparison to normal controls at both times. We observed an impairment of the hemorheological pattern in young patients with myocardial infarction, partially influenced by the infarction type (STEMI and NSTEMI) and persisting in the long term.

Clinical conditions responsible for hyperviscosity and skin ulcers complications.

In this brief review, we have examined some clinical conditions that result to be associated to an altered hemorheological profile and at times accompanied by skin ulcers. This skin condition may be observed in patients with the following condtions, such as primary polycythemic hyperviscosity (polycythemia, thrombocytemia) treated with hydroxyurea, primary plasma hyperviscosity (multiple myeloma, cryoglobulinemia, cryofibrinogenemia, dysfibrinogenemia, and connective tissue diseases), primary sclerocythemic hyperviscosity (hereditary spherocytosis, thalassemia, and sickle cell disease). In addition, it may be present in patients with secondary hyperviscosity conditions such as diabetes mellitus, arterial hypertension, critical limb ischemia and chronic venous insufficiency.

Clinical disorders responsible for plasma hyperviscosity and skin complications.

In this brief review, we have examined some clinical disorders which are associated to an altered hemorheological profile and at times accompanied by skin ulcers. This skin condition may be, in fact, observed in patients with primary plasma hyperviscosity such as multiple myeloma, Waldenstrom macroglobulinemia, cryoglobulinemia, cryofibrinogenemia, dysfibrinogenemia and connective tissue diseases. It must be underlined that the altered hemorheological pattern is not the only responsible for this skin complication but, as it worsens the microcirculatory flow, it contributes to determine the occurrence of the skin ulcers.

[Analysis of the parameters, traditional or not, for the evaluation of the metabolic acidosis]. / Considerazioni sui parametri di valutazione, tradizionali e non, delle acidosi metaboliche.

Despite huge progress in acidbase knowledge, several confusing, irrational and controversial issues still remain. Acid-base disturbances have been usually evaluated with the traditional Henderson-Hasselbach method and with BE evaluation that seem inadequate since they define the magnitude of metabolic acidosis rather than its cause. Some studies have shown that the traditional approach is often not able to highlight the complicated acid-base disorders in critically ill patients; in these subjects, the possibility to identify tissue acids could offer a greater prognostic value than the evaluation of traditional parameters. An alternative approach is the Stewarts physiochemical method that defines the aetiology of a metabolic acidosis by quantifying the tissue acids. But the clinical utility of this method is limited due to its mathematical complexity. Therefore, some parameters of simplification were proposed in order to allow greater clinical applicability of this system. Specifically, it was observed that in the presence of metabolic acidosis, the chloride/sodium ratio (Cl-/Na+ ratio) or the sodium-chloride difference (DiffNa-Cl) would be useful indicators of the presence of unmeasured anions (UMA) and/or lactate.

Gelatinases and their tissue inhibitors in a group of subjects with obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS) is associated with an elevated risk of cardiovascular events and stroke. Matrix metalloproteinases (MMPs) are endopeptidases involved in extracellular matrix degradation and then in the development and progression of cardiovascular diseases. Our aim was to evaluate plasma levels of gelatinases (MMP-2 and MMP-9) and their tissue inhibitors (TIMP-1 and TIMP-2) in a group of subjects with OSAS. We enrolled 48 subjects (36 men and 12 women; mean age 49.7 ± 14.68 yrs) with OSAS diagnosed with a 1-night cardiorespiratory study and then we subdivided these subjects into two subgroups according to the apnea/hypopnea index (AHI): Low (L = 21 subjects with AHI <30) and High (H = 27 subjects with AHI >30). We measured plasma concentration of the gelatinases and their inhibitors using ELISA kits. We observed a significant increase in plasma concentration of MMP-9, MMP-2, TIMP-1 and TIMP-2 in the entire group of OSAS subjects and in the two subgroups, with higher levels in the H in comparison with the L subgroup. In the whole group of OSAS subjects we also noted a significant decrease in MMP-9/TIMP-1 ratio in comparison with normal controls. Only MMP-9 was significantly correlated with the severity of the disease, expressed as AHI, with the oxygen desaturation index and also with the mean oxygen saturation. MMPs pattern is altered in OSAS and significantly influenced by the severity of the disease; it probably contributes to the vascular remodeling that leads to the atherosclerotic disease and cardiovascular complications.

Lipid peroxidation and nitric oxide metabolites in a group of subjects with obstructive sleep apnea syndrome.

It is known that in OSAS the plasma lipid peroxidation has an opposite behavior in comparison with nitric oxide metabolites. In the re-examination of our survey of OSAS subjects we calculated the ratio between thiobarbituric acid reactive substances (TBARS) and nitric oxide metabolites (NOx) in relation to OSAS severity. The study has regarded 48 OSAS subjects subdivided in two subgroups according to the apnea/hypopnea index - AHI- (Low = 21 subjects with AHI <30 and High = 27 subjects with AHI >30). From the obtained data it is evident that the TBARS/NOx ratio is significantly higher in the H subgroup compared to L subgroup as well as this ratio is reduced in L subgroup in comparison with the whole group of OSAS subjects. In the entire group of OSAS subjects the TBARS/NOx ratio results positively correlated with AHI and ODI and inversely correlated with mSO2.

Acid-base and electrolyte abnormalities in heart failure: pathophysiology and implications.

Electrolyte and acid-base abnormalities are a frequent and potentially dangerous complication in subjects with congestive heart failure. This may be due either to the pathophysiological alterations present in the heart failure state leading to neurohumoral activation (stimulation of the renin-angiotensin-aldosterone system, sympathoadrenergic stimulation), or to the adverse events of therapy with diuretics, cardiac glycosides, and ACE inhibitors. Subjects with heart failure may show hyponatremia, magnesium, and potassium deficiencies; the latter two play a pivotal role in the development of cardiac arrhythmias. The early identification of these alterations and the knowledge of the pathophysiological mechanisms are very useful for the management of these patients.

Physiopathological, Epidemiological, Clinical and Therapeutic Aspects of Exercise-Associated Hyponatremia.

Exercise-associated hyponatremia (EAH) is dilutional hyponatremia, a variant of inappropriate antidiuretic hormone secretion (SIADH), characterized by a plasma concentration of sodium lower than 135 mEq/L. The prevalence of EAH is common in endurance (<6 hours) and ultra-endurance events (>6 hours in duration), in which both athletes and medical providers need to be aware of risk factors, symptom presentation, and management. The development of EAH is a combination of excessive water intake, inadequate suppression of the secretion of the antidiuretic hormone (ADH) (due to non osmotic stimuli), long race duration, and very high or very low ambient temperatures. Additional risk factors include female gender, slower race times, and use of nonsteroidal anti-inflammatory drugs. Signs and symptoms of EAH include nausea, vomiting, confusion, headache and seizures; it may result in severe clinical conditions associated with pulmonary and cerebral edema, respiratory failure and death. A rapid diagnosis and appropriate treatment with a hypertonic saline solution is essential in the severe form to ensure a positive outcome.