Urinary n-acetyl-beta-d-glucosaminidase excretion: an indicator of neuropathy in type 2 diabetes.

The established marker for tubular damage, urinary n-acetyl-beta-d-glucosaminidase is significantly increased in type 1 and 2 diabetes patients and is related to albuminuria and other diabetic complications. In this cross sectional study of type 2 diabetes patients with a history of albuminuria, we studied the relationship between excretion of n-acetyl-beta-d-glucosaminidase in urine and diabetic neuropathy.160 type 2 diabetes patients were screened for diabetic peripheral neuropathy and cardiovascular autonomic neuropathy. N-acetyl-beta-d-glucosaminidase excretion was detected in 24 h urine samples.Urinary excretion of n-acetyl-beta-d-glucosaminidase correlated significantly with -glucose control (fasting glucose r=0.18; p=0.04; HbA1c r=0.20; p=0.02) and urine albumin excretion (r=0.22; p=0.01). Binary regression analyses showed that increased urinary n-acetyl-beta-d-glucosaminidase concentration is an independent predictor for presence of clinical symptoms of peripheral neuropathy (OR 1.8 [95%CI 1.2-2.74] and vibration deficiency [OR 1.7; 95% CI 1.2-2.66]. There was also a significant negative association between urinary n-acetyl-beta-d-glucosaminidase and E/I-Ratio (r=-0.21, p<0.02) as well as the 30:15-Ratio (r=-0.24; p<0.01) of heart rate variability. Furthermore, increased n-acetyl-beta-d-glucosaminidase excretion independently predicted cardiovascular autonomic diabetic neuropathy with an OR for decreased E/I-Ratio of 1.7 [95%CI 1.1-2.75]; (p<0.02) and 30:15-Ratio:OR 2.4 [95% CI 1.26-4.45]; (p<0.01).Urinary n-acetyl-beta-d-glucosami-nidase excretion is an independent marker for diabetic peripheral and cardiovascular autonomic neuropathy in type 2 diabetic patients.

Spironolactone diminishes urinary albumin excretion in patients with type 1 diabetes and microalbuminuria: a randomized placebo-controlled crossover study.

AIMS: Adding aldosterone receptor blockade to standard renoprotective treatment may provide additional renoprotection in patients with overt nephropathy. We expected an impact of spironolactone in early diabetic nephropathy, and for this hypothesis we studied the effect on markers of glomerular and tubular damage in patients with Type 1 diabetes and persistent microalbuminuria. METHODS: A double-blind, randomized, placebo-controlled crossover study in 21 patients with Type 1 diabetes and microalbuminuria using spironolactone 25 mg or placebo once daily, for 60 days added to standard antihypertensive treatment. After each treatment period, the primary endpoint were evaluated: urinary(u)-albumin excretion/24 hour(h) and secondary endpoints; 24 h blood pressure, glomerular filtration rate (GFR) and markers of tubular damage: urinary liver-type fatty-acid binding protein (LFABP), neutrophil gelatinase associated lipocalin (NGAL) and kidney injury molecule 1 (KIM1). RESULTS: All patients completed the study. During spironolactone treatment, urinary albumin excretion rate was reduced by 60% (range 21-80%), from 90 mg/24 h to 35 mg/24 h (P=0.01). Blood pressure (24 h) did not change during spironolactone treatment (P>0.2 for all comparisons). The GFR (SD) decreased from 78 (6) mL/min/1.73 m(2) to 72 (6) mL/min/1.73 m(2) (P=0.003). Urinary liver-type fatty-acid binding protein, neutrophil gelatinase-associated lipocalin and kidney injury molecule 1 did not change during treatment (P>0.3 for all comparisons). Treatment was well-tolerated, but two patients had severe hyperkalaemia (plasma potassium = 5.7 mmol/l), which was sufficiently treated with diuretics and dietary intervention. CONCLUSIONS: Spironolactone treatment in addition to standard renoprotective treatment lowers urinary albumin excretion in microalbuminuric patients with Type 1 diabetes, and thus may offer additional renoprotection independent of blood pressure.

Cardiac troponin T concentrations above the 99th percentile value as measured by a new high-sensitivity assay predict long-term prognosis in patients with acute coronary syndromes undergoing routine early invasive strategy.

OBJECTIVE: A recently developed immunoassay for high-sensitivity measurement of cardiac troponin T (hsTnT) allows measurement at the 99th percentile for a normal population with an assay imprecision <10%. It is unclear whether such a low cutpoint (14 ng/L) is helpful for long-term risk stratification of patients with an acute coronary syndrome (ACS) undergoing routine early invasive strategy. PATIENTS AND MAIN OUTCOME MEASURES: Consecutive patients with ACS admitted to a chest pain unit were studied. The usefulness of hsTnT for early diagnosis of myocardial infarction (MI) and prediction of all-cause death or death/MI over a median of 271 days following presentation was compared against the fourth generation cTnT at the 99th percentile cutpoint. RESULTS: Of 1,384 patients with ACS enrolled, 47.8% had non-ST-segment elevation MI (NSTEMI), 26.4% unstable angina, 21.8% STEMI and 4% had non-ACS. Adjusted risk for all-cause death [adjusted HR 8.26 (95%CI: 1.13-66.33), p = 0.038] and death/MI [adjusted HR 2.71 (95% CI: 1.15-6.38), p = 0.023] were significantly higher with hsTnT above the 99th percentile. In particular, among patients with a standard fourth generation cTnT result below the 99th percentile cutoff (0.01 ng/mL), hsTnT improved risk assessment. Mortality risk associated with an elevated hsTnT was present across the spectrum of ACS, as well as in conditions with hsTnT elevations not related to ACS. CONCLUSION: hsTnT at the 99th percentile cutoff is useful for the diagnostic evaluation of patients with ACS, and provides strong and independent predictive power for adverse long-term outcomes even after early invasive strategy.

Circulating cardiovascular biomarkers in recurrent atrial fibrillation: data from the GISSI-atrial fibrillation trial.

OBJECTIVE: we evaluated the prognostic role of circulating cardiovascular biomarkers in patients with a history of recent atrial fibrillation (AF). BACKGROUND: predicting long-term maintenance of sinus rhythm in patients with AF is difficult. METHODS: plasma concentrations of three specific cardiac markers [high-sensitivity troponin T (hsTnT), N-terminal probrain natriuretic peptide (NT-proBNP) and mid-regional proatrial natriuretic peptide (MR-proANP)] and three stable fragments of vasoactive peptides [mid-regional proadrenomedullin (MR-proADM), copeptin (CT-proAVP) and CT-proendothelin-1 (CT-proET-1)] were measured at baseline and after 6 and 12 months in 382 patients enrolled in the GISSI-AF study, a prospective randomized trial to determine the effect of valsartan to reduce the recurrence of AF. The association between these markers, clinical characteristics and recurrence of AF was tested by univariate and multivariate Cox models. RESULTS: mean patient age was 68 ± 9 years (37.2% females). A total of 84.8% of patients had a history of hypertension. In total, 59.7% qualified for history of AF because of successful cardioversion, 11.8% because of two or more episodes of AF in the 6 months preceding randomization and 28.5% because of both. Patients in AF at 6 or 12 months (203 (53.1%) with first recurrence) had significantly higher concentrations of most biomarkers. Despite low baseline levels, higher concentrations of hsTnT {adjusted hazard ratio (HR) [95% confidence intervals (CIs) for 1 SD increment] (1.15 [1.04-1.28], P = 0.007), MR-proANP (1.15 [1.01-1.30], P = 0.04), NT-proBNP (1.24 [1.11-1.39], P = 0.0001) and CT-proET-1 (1.16 [1.01-1.33], P = 0.03) independently predicted higher risk of a first recurrence of AF. Changes over time of MR-proANP tended to predict subsequent recurrence (adjusted HR [95%CI]) (1.53 [0.98-2.37], P = 0.06). CONCLUSION: circulating markers of cardiomyocyte injury/strain and endothelin are related to recurrence of AF in patients in sinus rhythm with a history of recent AF.

Urinary L-FABP and anaemia: distinct roles of urinary markers in type 2 diabetes.

BACKGROUND: Urinary liver-type fatty acid binding protein (L-FABP) and kidney injury molecule (KIM)-1, novel urinary biomarkers of renal tubulointerstitial function, have previously been associated with acute ischaemic kidney injury. We studied the clinical significance of urinary L-FABP, KIM-1 and N-acetyl-beta-glucosaminidase (NAG) as potential markers of renal function and chronic ischaemic injury in patients with diabetic nephropathy. MATERIAL AND METHODS: A total of 130 type 2 diabetes patients with early diabetic nephropathy and 40 healthy controls were studied. Urinary L-FABP, KIM-1, NAG, albumin excretion rate (AER) and creatinine clearance were obtained from 24-h urine samples, and correlated with measures of red blood cell count, renal function and metabolic control. RESULTS: Urinary L-FABP was significantly increased in diabetes patients compared with healthy controls [8.1 (interquartile 0.6-11.6) vs. 2.4 (0.5-3.6) microg/g creatinine, P < 0.001] and correlated with AER (r = 0.276, P = 0.002), creatinine clearance (r = -0.189, P = 0.033) and haemoglobin levels (r = -0.190, P = 0.030). In multivariable linear regression analysis, haemoglobin (beta = -0.247, P = 0.015) and AER (beta = 0.198, P = 0.046) were significant predictors of urinary L-FABP. Prevalent anaemia was independently associated with a 6-fold risk for increased tubulointerstitial kidney damage (upper vs. lower two L-FABP tertiles: OR, 6.06; 95% CI: 1.65-22.23; P = 0.007). Urinary KIM-1 was not significantly associated with kidney function, AER, or measures of red blood cell count while urinary NAG was associated with parameters of glucose control and renal function. CONCLUSIONS: Different urinary biomarkers may reflect distinct pathophysiological mechanisms of tubulointerstitial damage in early diabetic nephropathy: Urinary L-FABP could be a novel biomarker for chronic intrarenal ischaemia.

N-terminal pro-B-type natriuretic peptide (NT-proBNP) in HIV-1 infected individuals on HAART.

BACKGROUND: Studies suggest that highly active anti-retroviral therapy (HAART) prolongs life in HIV infected individuals and that HIV infected individuals increasingly suffer from cardiovascular complications. NT-proBNP has been shown to represent an indicator of cardiac function. METHODS: 495 HIV infected individuals under HAART and 1980 blood donors (BD) were tested for N-terminal pro-B-type natriuretic peptide (NT-proBNP). NT-proBNP was performed by an automated electrochemiluminescence immunoassay (ECLIA) method. RESULTS: HIV infected individuals had significantly higher NT-proBNP levels than age matched blood donors (18-29 y: median: 33 pg/ml HIV vs. 5 pg/ml BD; p = 0.0247; 30-39 y: median: 25 pg/ml HIV vs. 5 pg/ml BD; p = 0.0351; 40-49 y: median: 35.5 pg/ml HIV vs. 5 pg/ml BD; p < 0.0001; 50-59 y: median: 42 pg/ml HIV vs. 36 pg/ml BD; p = 0.3665; 60-69 y: median: 82.5 pg/ml HIV vs. 46 pg/ml BD; p = 0.0055) the effect was consistently found in all age and both gender groups. HIV infected individuals differed from the blood donor control group with respect to cardiovascular risk factors (hypertension, cardiovascular (CV) medication, diabetes mellitus, smoking status). In HIV infected individuals NT-proBNP levels did not correlate to cardiovascular risk factors including GFR except for C-reactive protein (CRP) levels using multivariate analysis. There was also no evidence for cardiotoxic effects due to HAART or specific antiretroviral drugs. High NT-proBNP levels were found in Hepatitis C virus (HCV) infected individuals who had received alpha-interferon therapy. CONCLUSIONS: HIV infected individuals had higher NT-proBNP levels than age matched blood donors possibly as a result of a higher prevalence of general cardiovascular risk factors and HIV associated risk factors, the finding is consistent with an increased incidence of cardiovascular events described in HIV infected individuals. Further studies on the relationship to cardiovascular outcome are warranted.

Effect of stress-induced reversible ischemia on serum concentrations of ischemia-modified albumin, natriuretic peptides and placental growth factor.

OBJECTIVE: There is controversy whether new biomarkers are able to identify myocardial ischemia in the absence of myonecrosis. METHOD: We measured NT-pro BNP, NT-pro ANP, ischemia-modified albumin (IMA) and placental growth factor (PlGF) in patients undergoing nuclear stress testing for suspected ischemic heart disease. A thallium scan was used for detection of reversible myocardial ischemia and cardiac troponin T (cTnT) for exclusion of stress-induced myonecrosis. Of 195 patients, 24 with reversible and 62 with no perfusion defect were included in the analysis. Plasma levels were measured before, 18 min and 4 h after stress testing. RESULTS: Of the 86 patients, 52 received an exercise stress and 34 dipyridamol. New myonecrosis indicated by cTnT could be excluded in all patients. Plasma levels of NT-pro BNP and NT-pro ANP before testing were significantly higher in patients who later developed reversible perfusion defects (NT-pro BNP 139.00 (58.25/367.01) pg/mL vs 327.45 (120.50/972.85) pg/mL, p<0.05; NT-pro ANP 732.5 (470.0/1220.0) pg/mL vs 1470.0 (694.0/1910.0) pg/mL, p<0.05). Plasma levels of NT-pro BNP, NT-pro ANP and PIGF did not change significantly after stress testing, IMA levels rose significantly after 4 h in patients with and without reversible perfusion defects. CONCLUSION: The elevation of NTpro BNP and NT-pro ANP at baseline may represent the cumulative effect of repeated bouts of myocardial ischemia. A single brief episode of provoked ischemia does not cause a significant increase of the measured biomarkers beside from IMA after exercise stress test potentially indicating skeletal muscle ischemia.

Effect of primer selection on estimates of GB virus C (GBV-C) prevalence and response to antiretroviral therapy for optimal testing for GBV-C viremia.

GB virus C (GBV-C; also called hepatitis G virus) is a common cause of infection associated with prolonged survival among HIV-infected individuals. The prevalences of GBV-C viremia vary widely in different studies, and there has been poor agreement among different laboratories performing GBV-C RNA detection in quality control studies. To determine the optimal method of measuring GBV-C RNA in clinical samples, samples obtained from 939 HIV-infected subjects were studied using reverse transcription (RT)-PCR methods amplifying four separate regions of the GBV-C genome. Primers amplifying the E2 coding region were 100% specific; however, their sensitivity was only 76.6%. In contrast, primers amplifying three additional conserved regions of the GBV-C genome (the 5' nontranslated region and the nonstructural protein-coding regions 3 and 5A) were more sensitive but produced higher rates of false-positive results. Using low-specificity primer sets influenced the significance of association between GBV-C viremia and response to antiretroviral therapy. Using a quantitative GBV-C RNA method, the GBV-C RNA concentration did not correlate with baseline or set point HIV RNA levels; however, a correlation between negative, low, and high GBV-C RNA levels and increasing reduction in HIV RNA following antiretroviral therapy was observed. Subjects with both GBV-C E2 antibody and viremia had significantly lower GBV-C RNA levels than did viremic subjects without E2 antibody. These studies demonstrate that accurate detection of GBV-C RNA by nested RT-PCR requires the use of primers representing multiple genome regions. Analyses based on testing with single primers do not lead to reliable conclusions about the association between GBV-C infection and clinical outcomes.

N-Terminal-proBNP (NT-proBNP) as an indicator of cardiac dysfunction. A study in patients presenting with suspected cardiac disorders.

BACKGROUND: Natriuretic peptides represent a novel diagnostic tool in the assessment of cardiac dysfunction. METHODS: A total of 473 consecutive referred patients presenting to 18 cardiologists for the assessment of their cardiac state were recruited for the study. Patients received a medical history, a physical examination an electrocardiogram and an echocardiogram where left ventricular ejection fraction was recorded. RESULTS: NT-proBNP was found to correlate with left ventricular ejection fraction (LVEF), level of symptoms (NYHA classification), history of angina pectoris (AP) and myocardial infarction (AMI). Atrial fibrillation (AF) and thyroid dysfunction as well as renal impairment were shown to influence NT-proBNP levels. CONCLUSION: The study supports the hypothesis that NT-proBNP determination contributes to the assessment of patients presenting to cardiologists.

Correlation of interferon treatment response with GBV-C/HGV genomic RNA and anti-envelope 2 protein antibody.

The clinical significance of GB virus C/hepatitis G virus (GBV-C/HGV) co-infection was studied retrospectively in 100 consecutive patients with hepatitis C virus (HCV) infection. All 100 patients had been treated with interferon-alpha (IFN-alpha). Co-infection with GBV-C/HGV and HCV was detected in 10 of the 100 patients (10%) and anti-envelope 2 region (anti-E2) antibody was detected in 25 patients. None of the patients with GBV-C/HGV RNA had anti-E2 antibody. Co-infected patients were younger (P < .005) and their serum transaminase levels were lower than HCV-only infected patients (P< .01). In 7 of the 10 co-infected patients, HCV RNA was eradicated from serum after IFN-alpha treatment and normal alanine transaminase (ALT) levels continued in 6 of these 7 patients. In one patient who was negative for HCV RNA but positive for GBV-C/HGV RNA, the ALT level relapsed transiently. The rate of clearance of HCV and normalization of the ALT level was significantly higher in co-infected patients than in HCV-only infected patients (P < .05). GBV-C/HGV RNA disappeared from 6 of the 10 co-infected patients (60%) upon cessation of IFN-alpha treatment. However, continuous clearance of GBV-C/HGV was observed in only two patients and anti-E2 antibody could not be detected in the serum of these patients. These results indicate that co-infected patients tend to be younger and more sensitive to IFN-alpha treatment. However, long-term clearance of GBV-C/HGV after IFN-alpha treatment may be difficult. Moreover, anti-E2 antibody may act to neutralize GBV-C/ HGV.

Hepatitis G virus RNA is common in AIDS patients' plasma but is not associated with abnormal liver function tests or other clinical syndromes.

Hepatitis G virus (HGV) is a new virus found in 1% to 4% of blood from all donors but is more prevalent in some immunocompromised groups, with unclear clinical significance. Frozen plasma samples from 192 AIDS patients were tested for HGV RNA; 44 (23%) were positive. Positive patients did not differ from negative patients in age, gender, race, HIV infection risk factors, nor blood transfusion exposure. Hepatitis BsAg was associated with HGV infection (odds ratio [OR] = 7.7; 95% confidence interval [CI], 2.4-25.0) but hepatitis C antibody was not. Mean values for liver function tests and hematologic values did not differ significantly between the groups nor did the occurrence of certain recognized AIDS-related complications. Mean CD4+ cell counts and HIV-1 plasma RNA levels were comparable in the two groups, but the mean circulating CD8+ cell count in the HGV-positive group (853+/-458 cells/microL) was higher than in the negative group (682+/-457 cells/microL; p = .03). Hepatitis G virus, although common in AIDS patients, does not appear to alter the course of AIDS nor appear as a distinct hepatitis syndrome.

Quantitative determination of albumin in urine by on-line immunoadsorptive cleanup and reversed-phase chromatography.

Albumin in urine is selectively adsorbed on an immunoadsorber (human serum albumin-specific antibodies coupled covalently with a silica stationary phase) and after elution with 0.1% HCl is quantitatively determined by reversed-phase chromatography with detection of native fluorescence. The optimization of sample preparation and characteristics of the method such as recovery, linearity, reproducibility, detection limit, and selectivity are discussed.

Pyruvate attenuation of hypoxia damage in isolated working guinea-pig heart.

Function and various parameters of myocardial substrate and energy metabolism were measured in preload-controlled isolated working guinea-pig hearts perfused with normoxic (95% O2) and hypoxic (30 to 45% O2) Krebs-Henseleit buffers ([Ca2+] = 1.25 mM). Energy-yielding substrates were glucose, pyruvate, lactate, and fatty acids (acetate, octanoate). Hypoxia typically produced an increase in coronary flow but a fall in cardiac oxygen uptake (MVO2); left ventricular pressure and work parameters as well as myocardial high energy phosphate levels were decreased while the releases of adenosine plus inosine (V (Ado + Ino)) and lactate were increased. Extra pyruvate (1 to 5 mM) as compared to physiologic concentrations of pyruvate (0.2 mM) produced a relative stabilization of left ventricular pressure and work parameters combined with an attenuation of V (Ado + Ino) provided 5 to 10 mM glucose was the cosubstrate. Coinfusion of 2-deoxyglucose, a nondegradable hexose, in presence of excess pyruvate as sole substrate was without effects on residual ventricular pump function. When 1 mM lactate plus 5 mM glucose were the substrates, hypoxic heart function was also depressed, V (Ado + Ino) was relatively increased, and post-hypoxic recovery of pressure parameters was impaired. Similarly, the fatty acid substrates tested seemed to adversely affect cardiac performance during hypoxia. Extra pyruvate in presence of glucose induced a fall in hypoxic myocardial lactate and alpha-glycerophosphate contents while cellular citrate reached millimolar levels. Obviously, utilizable amounts of glucose were required for pyruvate stabilization of the high flow hypoxic heart. The beneficial effects of pyruvate appeared to depend on a functioning glycolysis; other effects seemed to include redox-related changes in energy state and/or purine nucleoside metabolism as well as a possible citrate buffering of intracellular Ca2+ load.