Ottavio Giampietro

Microalbuminuria and endothelial dysfunction in essential hypertension

Microalbuminuria (urinary albumin excretion between 20 and 200 micrograms/min) and endothelial dysfunction coexist in patients with essential hypertension. To evaluate whether the two phenomena are related and the determinants of that association, we recruited 10 untreated males with essential hypertension and microalbuminuria without diabetes to be compared with an equal number of matched patients with essential hypertension excreting albumin in normal amounts and 10 normal controls. The status of endothelial function was inferred from circulating von Willebrand Factor antigen (vWF), a glycoprotein secreted in greater amounts when the vascular endothelium is damaged. vWF concentrations were higher in hypertensive patients with microalbuminuria than in hypertensive patients without and controls. Individual vWF and urine albumin-excretion values were correlated (r = 0.55, p < 0.002). Blood pressure correlated with both urinary albumin excretion and vWF. Left ventricular mass index and minimal forearm vascular resistances were comparable in patients with hypertension and higher than in controls; total and low-density lipoprotein cholesterol, triglycerides, lipoprotein-a, Factor VII, and plasminogen activator inhibitor-1 did not differ. Fibrinogen was higher and creatinine clearance lower in microalbuminurics. Albuminuria in essential hypertension may reflect systemic dysfunction of the vascular endothelium, a structure intimately involved in permeability, haemostasis, fibrinolysis, and blood pressure control. This abnormality may have important physiopathological implications and expose these patients to increased cardiovascular risk.

relation of Glucose Tolerance to Complications of Pregnancy in Nondiabetic Women

Abstract An increase in fetal and maternal complications has been documented in cases of gestational diabetes, but the glucose levels that predict an increased risk have not been clearly defined. We evaluated the frequency of several neonatal complications (macrosomia, congenital anomalies, perinatal mortality, and prematurity) and maternal complications (toxemia, cesarean section, or both) in relation to glucose tolerance in 249 women in the third trimester of pregnancy. None of the women had previous evidence of diabetes, and all had normal results on an oral glucose-tolerance test, according to accepted criteria. On the basis of their two-hour plasma glucose levels, women were divided into three groups: A (glucose <100 mg per deciliter), B (glucose 100 to 119 mg per deciliter), and C (glucose 120 to 164 mg per deciliter). The higher two-hour plasma glucose levels were associated with a significant increase in the incidence of macrosomia (9.9, 15.5, and 27.5 percent in Groups A, B, and C, respectively),...

Increased echodensity of myocardial wall in the diabetic heart: An ultrasound tissue characterization study

OBJECTIVES We sought to characterize myocardial echodensity in asymptomatic patients with insulin-dependent diabetes and normal conventional two-dimensional echocardiographic findings to determine whether ultrasound tissue characterization can detect ultrastructural changes in myocardium, such as an increase in collagen content. BACKGROUND Fibrosis alters the acoustic properties of the heart in animals and humans, and these changes are detectable by cardiac tissue characterization with ultrasound. Early changes detected in the diabetic heart include increased interstitial collagen deposition. METHODS Using two-dimensional echocardiography, we evaluated 26 asymptomatic patients with insulin-dependent diabetes with normal regional and global rest function, and 17 age- and gender-matched control subjects. By selection, all diabetic patients were normotensive and had negative maximal exercise stress test results to avoid the confounding effects of hypertension and coronary artery disease. Using an echocardiographic instrument implemented at the Institute of Clinical Physiology, we performed an on-line radiofrequency analysis to obtain quantitative operator-independent measurements of the integrated back-scatter signal of the ventricular septum and posterior wall. The integrated values of the radiofrequency signal from the myocardial wall were normalized for those from the pericardial interface and were expressed as percentages (integrated backscatter index). RESULTS Diabetic patients showed a significant increase in myocardial echodensity both in the septum ([mean +/- SD] 36.6 +/- 8.1 vs. 23.6 +/- 4.4, p < 0.0001) and posterior wall (21.2 +/- 5.3 vs. 18.4 +/- 3.7, p < 0.001). By individual patient analysis, 17 patients exceeded the 95% confidence limits for normal myocardial echocardiographic reflectivity found in normal subjects, and only 3 had a relatively abnormal transmitral Doppler filling pattern (E/A ratio), mainly consisting of an abnormally increased late peak flow velocity (65% vs. 11%, p < 0.001). The increased myocardial intensity was similar in patients with (n = 16) and without (n = 10) noncardiac complications, such as retinopathy or nephropathy (37.5 +/- 7.9% vs. 35.0 +/- 8.3%, p = 0.35). CONCLUSIONS Abnormally increased myocardial echodensity, possibly related to collagen deposition, can be detected in asymptomatic diabetic patients with normal rest function. Theoretically, this finding might be considered a very early preclinical alteration potentially related to subsequent development of diabetic cardiomyopathy.

Malnutrition, anorexia and cachexia in cancer patients: A mini-review on pathogenesis and treatment

Malnutrition, anorexia and cachexia are a common finding in cancer patients. They become more evident with tumor growth and spread. However, the mechanisms by which they are sustained often arise early in the history of cancer. For malnutrition, these mechanisms can involve primary tumor or damage by specific treatment such as anticancer therapies (surgery, chemotherapy, radiotherapy) also in cancers that usually are not directly responsible for nutritional and metabolic status alterations (i.e. bone tumors). For anorexia, meal-related neural or hormonal signals and humoral signals related to body fat or energy storage and the interaction of these signals with the hypothalamus or the hypothalamic inappropriate response play a pathogenetic role. Some cytokines are probably involved in these mechanisms. For cachexia, the production of proinflammatory cytokines by tumour cells is the initial mechanism; the main biochemical mechanisms involved include the ubiquitine proteasome-dependent proteolysis and heat shock proteins. Treatment includes pharmaceutical and nutritional interventions.

Asymptomatic Bacteriuria in Women with Diabetes: Influence of Metabolic Control

We screened 228 women with diabetes for bacteriuria during the period of January 1997 through December 2000 at Pisa General Hospital (Pisa, Italy). A control group of 146 women without diabetes was also evaluated. The frequency of significant bacteriuria was 17.5% (40 of 228) among women with diabetes and 18.5% (27 of 146) among women in the control group. Seven (13.5%) of 52 and 33 (18.8%) of 176 women with type 1 and in type 2 diabetes, respectively, had significant bacteriuria. The presence of higher glycated hemoglobin levels was the only significant risk factor for significant bacteriuria in women with type 2 diabetes. A similar frequency of bacteriuria in women with and women without diabetes was found. Severe impairment of metabolic control of type 2 diabetes increases the risk of acquiring asymptomatic bacteriuria.

ARTERIAL HYPERTENSION AND MICROALBUMINURIA IN IDDM : THE ITALIAN MICROALBUMINURIA STUDY

SummaryArterial hypertension and poor glycaemic control are central to the development of microalbuminuria in insulin-dependent diabetes mellitus (IDDM). Recent consensus has established sensitive criteria for their detection and treatment, although the proportion of patients who may benefit is unclear. Between 1988 and 1990, we measured urinary albumin to creatinine concentration ratio (A/C) in 3,636 adult out-patients with IDDM of more than 3 years duration, serum creatinine under 133 Μmol/l and who were not undergoing antihypertensive treatment. A/C indicating microalbuminuria (≥2.38/ 2.96 mg/mmol, male/female) was found in 620 of 3,451 patients without proteinuria, and associated with hypertension (blood pressure ≥140 and/or 90 mm Hg; p=0.0016; rate: 39.6%), independent of diabetes duration (p=0.0082) and male gender (p=0.0350; relative risk=1.16; 95% confidence interval: 1.01–1.32). Hypertension was less common among those with normal A/C (27.5%, p<0.0001) but was positively related with diabetes duration. Of the 1,015 patients with A/C>2.0 mg/mmol 529 were reexamined. Glycated haemoglobin levels exceeded 3 SD above the mean of normal in 84.3% of the 198 microalbuminuric patients (AER=20–200 Μg/min), but were comparably poor (79.2%) in normoalbuminuria. Duration of diabetes was inversely related to glycated haemoglobin only in microalbuminuria (0.05<p<0.1). Intervention to lower blood pressure remains mainly restricted to those patients with long-term diabetes and slower development of kidney disease. Near-normalisation of glycaemia remains the priority for the majority of patients with microalbuminuria.

Thiol Signalling Network with an Eye to Diabetes

Redox regulatory system controls normal cellular functions. Controlled changes in redox couples potential serve as components for signal transduction, similarly to the phosphorylation cascade. Cellular redox biology requires both compartimentalisation and communication of redox systems: the thermodynamic disequilibrium of the major redox switches allows rapid and sensitive responses to perturbations in redox environments. The many oxidation states of sulphur are found in numerous sulphur species with distinct functional groups (thiols, disulphides, polysulphides, sulphenic, sulphinic and sulphonic acids, etc.), which participate in a complicated network of sulphur-based redox events. Human diseases such as diabetes mellitus and its cardiovascular complications have been associated with increased production of reactive oxygen species and perturbations of thiol redox homeostasis. The review surveys literature related to some etiopathogenic aspects and therapeutic perspectives. The dual toxic-protective property of sulphydryl-donor molecules in experimental settings proposes the general problem of designing antioxidants for therapeutic use.

Advanced oxidation protein products in plasma: stability during storage and correlation with other clinical characteristics

Abstract Proteins are susceptible to free radical damage. We measured advanced oxidation protein products (AOPP) in the plasma of 56 hospitalised patients. Concentrations of AOPP were expressed as chloramine-T equivalents by measuring absorbance in acidic conditions at 340 nm in the presence of potassium iodide. We also determined erythrocyte sedimentation rate (ESR), circulating urea, creatinine, glucose, uric acid, electrolytes, lipids, total proteins and fractions and fibrinogen. Twenty-four samples were processed both immediately and after 7, 15, 30, 90, 180 and 438 days of storage at both at −20°C and −80°C (aliquots were frozen and thawed only once) to evaluate AOPP stability. The remaining 32 samples were also processed for thiobarbituric-acid-reactive substances (TBARS). Mean AOPP concentration in all 56 patients was 48.3±37.2 μM. Mean basal concentration of AOPP in the 24 plasma samples (55.0±47.1 μM) showed no significant change at each intermediate determination, yet significantly increased after 438 days of storage both at −80°C (96.6±83.2, p<0.01) and, markedly, at −20°C (171.3±94.6, p<0.001). TBARS concentration was 1.59±:0.65 μmol/l. Multiple regression analysis evidence that AOPP concentration was positively correlated (multiple r=0.62, p<0.001) with serum urea and triglycerides, but negatively correlated with patient age (indeed, serum albumin and total proteins decreased with increasing age, r=0.3, p<0.05). TBARS concentration was associated with ESR and serum glucose (multiple r=0.73, p<0.001), yet positively with AOPP (r=0.39, simple p<0.05). We conclude that AOPP remain stable during sample storage both at −20°C and −80°C for 6 months. Renal failure and hypertriglyceridemia probably enhance the in vivo process of AOPP formation. Oxidative damage as measured by TBARS may be increased because of exposure to hyperglycemia causing nonenzymatic glycation of plasma proteins.

Which method for quantifying ?microalbuminuria? in diabetics?: Comparison of several immunological methods (immunoturbidimetric assay, immunonephelometric assay, radioimmunoassay and two semiquantitative tests) for measurement of albumin in urine

We have compared the chemical and clinical characteristics of an immunonephelometric assay (INA), two immunoturbidimetric assays (ITA) and two semiquantitative methods with those of a solid-phase radioimmunoassay (RIA) for measurement of urinary albumin (UA) concentration in 136 diabetic patients. INA and RIA had similar accuracy, and provided comparable results. However, RIA has slightly greater sensitivity than INA, which is easier and faster. Good agreement was also found between RIA and the two ITA methods, although one of these overestimated RIA values in the low-medium range (5–30 mg/l) of urinary albumin. ITA seems suitable for initial screening of albuminuria in diabetic patients but more sensitive procedures (such as RIA and INA) seem preferable for measurement of UA concentrations in the normal range. The two semi-quantitative methods showed high sensitivity but poor specificity, because of the large number of false positive results. About 50% of diabetic patients “positive” by these methods did not have microalbuminuria. The utility of these methods is questionable, because many samples from diabetic patients need to be reassayed by a more specific and sensitive assay such as the RIA, INA or ITA methods.

Prevalence of hypertension and microalbuminuria in adult type 1 (insulin-dependent) diabetic patients without renal failure in Italy. I. Validation of screening techniques to detect microalbuminuria

The prevalence of microalbuminuria and arterial hypertension among type 1 (insulin-dependent) diabetic patients is poorly known in Italy. In the preliminary phase of a large outpatient screening programme, we addressed the possibility of using non-time urine samples to predit the chance of detecting albumin excretion rate (AER) in the range of microalbuminuria. We therefore measured urinary albumin and creatinine concentration in timed overnight collections from 641 type 1 diabetic patients with serum creatinine levels lower than 133 μmol/l. AER was strongly and comparably predicted both by urinary albumin concentration (UAlb;r2=0.754) and by the urinary albumin to creatinine concentration ratio (A/C;r2=0.773). After exploring several independent cut-off levels for UAlb and A/C, AER in the range 20–200 μg/min (n=91) was found to be predicted with 90% sensitivity and specificity either by UAlb≧20 mg/l or by A/C≧2.0 mg/mmol. UAlb was negatively associated with diuresis, and false negative outcomes were explained by polyuria when screening by this variable. A/C was positively associated with female gender among normoalbuminuric patients, in line with the lower urinary excretion of creatinine in women (7.2±0.25 vs 10.2±0.35 μmol/min,P<0.00001). A significant excess of false positive outcomes in women compared with men was found when screening by any A/C cut-off level equal to or less than 2.5 mg/mmol. Simplified screening techniques seem to remain, however, a practicable option for the detection of microalbuminuria both in epidemiology and in clinical practice.