Comparison of urinary albumin, retinol-binding protein and N-acetyl beta-glucosaminidase as predictors of progression of low level albuminuria in diabetes.
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Acetylglucosaminidase↗
Biomedical subjects
G F Watts
Publications and source records attributed to G F Watts.
Management of lipid disorders in the elderly.
Cardiovascular disease has been inseparable from aging in developed societies and, as a result, it is the commonest cause of mortality in elderly populations. Atherosclerosis is associated with the progressive vascular accumulation of cholesterol-laden lipoproteins, and is linearly associated with the plasma level of low density lipoprotein (LDL) cholesterol. Clinical trials in patients aged < 65 years have conclusively shown that treatment of hypercholesterolaemia decreases the incidence of cardiovascular events and total mortality. However, few conclusive data are available regarding the treatment of hypercholesterolaemia in elderly patients. Extrapolation from clinical trials suggests that lipid lowering treatment in well selected elderly patients is effective in preventing cardiovascular events and is an efficient use of healthcare resources. In addition to cholesterol, high triglyceride and low high-density lipoprotein levels appear to be significant predictors of coronary artery disease in elderly patients. We do not advocate the indiscriminate screening of healthy elderly patients who have no other cardiovascular risk factors, because the marginal overall benefits are probably small and the costs of widespread screening and treatment high. On the other hand, chronological age itself cannot be considered a barrier to the screening and treatment of patients who have a good quality of life but have other cardiovascular risk factors and/or definite cardiovascular disease. Subgroup analysis of major clinical trials suggests that the aims of treatment should be to lower the LDL cholesterol level to 3.2 mmol/L (125 mg/dl), or the total cholesterol level to 5.2 mmol/L (200 mg/dl). Occasionally, multiple drug therapy is required to achieve this target, but statins (HMG-CoA reductase inhibitors) are the most commonly used first-line agents. With aggressive lowering of plasma lipid levels in this way, a reduction in clinical events is paralleled by regression of atheroma detectable by angiography, and an improvement in endothelial function. Global reduction of risk factors in elderly patients should always be undertaken, including dietary therapy, weight reduction in viscerally obese patients, postmenopausal estrogen replacement, smoking cessation, treatment of hypertension and control of diabetes mellitus. A secondary cause of dyslipidaemia should also be sought. The role of antioxidants is still not clear, but they are probably of little benefit in elderly patients. With the widespread use of effective, well tolerated treatments for lipid disorders in younger patients, significant improvements have already been attained in the morbidity and mortality associated with coronary artery disease. Since the current life expectancy at age 65 years is nearly 20 years in most Western countries, secondary prevention may increase the quality of life and the independent lifespan, even if eventual mortality is not delayed.
Aged↗
Serum sialic acid and the long-term complications of insulin-dependent diabetes mellitus.
Elevated serum sialic acid (SSA) predicts cardiovascular disease in the non-diabetic population and is also associated with the presence of microalbuminuria and clinical proteinuria in patients with insulin-dependent diabetes (IDDM). We have studied 121 patients with IDDM of long duration (mean duration 25.2 years) to investigate the relationship of SSA concentrations to the presence of retinopathy, nephropathy, and neuropathy. SSA levels were elevated in patients with retinopathy (0.578 +/- 0.161 gl-1, n = 98) when compared with those without retinopathy (0.468 +/- 0.145 gl-1, n = 23, p = 0.002). Patients with nephropathy (urinary albumin:creatinine ratio of > 3 mg mmol-1 in all of three early morning specimens of urine) also had raised SSA levels (0.625 +/- 0.169 gl-1, n = 30) compared with those without nephropathy (0.533 +/- 0.160 gl-1, n = 91, p = 0.006). There was a significant correlation of SSA with urinary albumin:creatinine ratio (correlation coefficient 0.33, p < 0.001). SSA levels were not related to the presence or absence of neuropathy (0.567 +/- 0.181 gl-1, n = 28, vs 0.533 +/- 0.160 gl-1, n = 93, p = 0.92, respectively). In conclusion, retinopathy and nephropathy but not neuropathy are associated with increased SSA levels in patients with IDDM. The significance of this is not yet clear but it is possible that sialic acid is involved in the pathophysiology of microvascular disease in IDDM.
Adult↗
Urinary infection and albumin excretion in insulin-dependent diabetes mellitus: implications for the measurement of microalbuminuria.
The frequency of urinary infection was determined using quantitative microbiology in 172 insulin-dependent diabetic patients repeatedly being tested for microalbuminuria over 18 months on at least six occasions. The point prevalence of urinary infection at first screening for microalbuminuria was 3%. Over the period of study, 20 of the patients (12%) showed evidence of urinary infection, defined as a pure growth of a recognized pathogen > 10(7)I-1. Infection was more common in women than men (20% vs 5%, p < 0.01) and was significantly associated with the presence of peripheral neuropathy (p < 0.05). Infection was not related to patient age, duration of diabetes, glycaemia, blood pressure, retinopathy or autonomic neuropathy. There were no significant within-patient differences in albumin excretion, glycaemic control or blood pressure in relation to the presence and absence of urinary infection. In only one patient (5%) did urinary infection significantly increase the urinary albumin excretion and this was associated with pyuria. We conclude that the presence of urinary infection does not apparently affect the measurement of urinary albumin excretion unless pyuria is present. Unless diabetic patients are symptomatic, examination of the urine for infection is probably unwarranted when testing for microalbuminuria.
Adult↗
Complete deficiency of plasma lecithin-cholesterol acyltransferase (LCAT) activity due to a novel homozygous mutation (Gly-30-Ser) in the LCAT gene.
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Adult↗
Lipids, lipoproteins, antioxidants and glomerular and tubular dysfunction in type 1 diabetes.
We aimed to examine the relationship of serum lipids, lipoproteins, apolipoproteins and antioxidants with renal dysfunction as measured by urinary excretion of albumin and of retinol binding protein (RBP) in insulin-dependent diabetes mellitus (IDDM). We studied 121 patients with IDDM. Glomerular function was assessed as the urinary albumin/creatinine ratio (UA/UC), and tubular function as the urinary retinol-binding protein/creatinine ratio (UR/UC), both measured in three early morning spot urine samples. The mean (range) UA/UC was 1.95 mg/mmol (0.3-476.5) and UR/UC was 17.5 micrograms/mmol (1.0-1853.8). 17% of the patients had a UA/UC > 3 mg/mmol and 33% had a UR/UC > 20 micrograms/mmol. Significant positive correlations were observed between both UA/UC and UR/UC and the following: serum total cholesterol (P < 0.005); triglycerides (P < 0.001); apolipoproteins A-I (P < 0.05), A-II (P < 0.02) and B (P < 0.002); glycated haemoglobin (P < 0.002). No significant associations were found with serum vitamin E, beta-carotene or total antioxidant activity. In multiple regression, only UA/UC was independently associated with serum apo B and cholesterol concentrations. In conclusion, in IDDM glomerular dysfunction, as measured by UA/UC, is associated with elevated serum cholesterol, triglycerides, apo B, apo A-I and apo A-II, but not with HDL cholesterol or antioxidant status. Tubular dysfunction tends to occur with increasing albuminuria, but it is not independently associated with serum lipid, lipoprotein, apolipoprotein or antioxidant levels.
Adult↗
Apolipoprotein B independently predicts progression of very-low-level albuminuria in insulin-dependent diabetes mellitus.
The purpose of the study was to examine the contribution of alterations in lipoprotein metabolism to the progression of very-low-level albuminuria in insulin-dependent diabetes mellitus (IDDM). We measured serum concentrations of lipids, lipoproteins, and apolipoproteins in 53 normoalbuminuric diabetic patients without overt hypertension, whom we restudied after 10 years. Albuminuria was measured as the urinary albumin to creatinine ratio (UA/UC) in repeated early-morning samples. Over 10 years, UA/UC increased significantly (P < .001), and five patients (9.4%) progressed to microalbuminuria. The increase in albuminuria was significantly and positively related to the baseline serum concentrations of total cholesterol (P < .05), low-density lipoprotein (LDL) cholesterol (P = .05), non-high-density lipoprotein (HDL) cholesterol (P < .05), and apolipoprotein (apo) B (P < .001), but no significant associations were found with triglycerides, HDL cholesterol, apo A-1, or lipoprotein(a) [Lp(a)]. The relative risk of developing microalbuminuria for a serum apo B concentration more than 1.1 g/L was 3.8 (95% confidence interval [CI], 1.9 to 7.7). In multiple linear regression analysis, serum apo B (P < .05) and glycated hemoglobin ([HbA] P < .05) at baseline were significant independent predictors of the increase in albuminuria, with no significant associations found for sex, smoking, duration of diabetes, mean arterial blood pressure (BP), or family history of cardiovascular disease and hypertension; the regression model predicted 42% of the variation in UA/UC at 10 years. The findings suggest that an abnormality in the metabolism of apo B may be independently associated with progression of very-low-level albuminuria and possibly with the development of early nephropathy in IDDM patients.
Adult↗
Impaired endothelium-dependent and independent dilatation of forearm resistance arteries in men with diet-treated non-insulin-dependent diabetes: role of dyslipidaemia.
1. We measured endothelium-dependent and independent dilatation of forearm resistance arteries in 29 men with diet-treated non-insulin-dependent diabetes mellitus and 18 age- and sex-matched control subjects. None of the diabetic patients had hypercholesterolaemia, overt hypertension or microproteinuria. 2. We examined endogenous and exogenous nitric oxide-mediated vasodilatation by measuring forearm blood flow with venous occlusive plethysmography after administration of acetylcholine (7.5 and 15 micrograms/min) and sodium nitroprusside (3 and 10 micrograms/min), respectively, into the brachial artery. NG-monomethyl-L-arginine was also infused to study the inhibition of basal and stimulated release of nitric oxide. 3. The vasodilatory response to acetylcholine, expressed as area under curve, was significantly decreased in the diabetic patients compared with the control subjects (P = 0.019). NG-monomethyl-L-arginine significantly reduced basal (P < 0.001) and acetylcholine-stimulated blood flow (P < 0.02) in both groups. The vasodilatory response (also expressed as area under curve) to sodium nitroprusside was significantly less (P = 0.044) in the diabetic patients than in the control subjects. 4. In the diabetic patients, impaired vasodilatory responses to acetylcholine were significantly correlated with higher serum triacylglycerols (P = 0.048) and lower high-density lipoprotein-cholesterol concentrations (P = 0.007); the association with high-density lipoprotein was independent of age, glycated haemoglobin and blood pressure. Sodium nitroprusside responses were not correlated with lipid and lipoprotein concentrations. 5. We conclude that there is impaired endothelial and smooth muscle cell function in men with diet-treated non-insulin-dependent diabetes mellitus uncomplicated by overt hypertension or microproteinuria. Endothelial dysfunction may be related to diabetic dyslipidaemia and associated metabolic disturbances.
Acetylcholine↗
Acute hyperinsulinaemia decreases cholesterol synthesis less in subjects with non-insulin-dependent diabetes mellitus than in non-diabetic subjects.
To investigate the effect of insulin on cholesterol synthesis in vivo we measured plasma mevalonic acid (MVA) concentrations using gas chromatography-mass spectrometry in six non-obese patients with non-insulin-dependent diabetes mellitus (NIDDM) [four men, two women; age 57.5 +/- 2.2 years (mean +/- SEM); glycated haemoglobin (HbA1) 8.5 +/- 0.5%; total cholesterol (TC) 5.7 +/- 0.5 mmol L-1, triglyceride (TG) 3.8 +/- 0.9 mmol L-1] and six non-diabetic, sex- and age-matched control subjects (age 55.7 +/- 2.8 years; HbA1 6.5 +/- 0.1%; TC 5.4 +/- 0.3 mmol L-1, TG 1.2 +/- 0.1 mmol L-1). Subjects were studied twice: during 13-h hyperinsulinaemic (1 mu kg-1 min-1), euglycaemic (5 mmol L-1) clamp and during a saline infusion. Baseline MVA concentration was significantly higher in diabetic patients than in control subjects (9.8 +/- 0.7 ng mL-1 vs. 5.6 +/- 0.9 ng mL-1, P = 0.004). At the end of each study, MVA concentration, expressed as a percentage of baseline, was significantly lower during the hyperinsulinaemic, euglycaemic clamp than during the saline study in both the diabetic (54.4 +/- 5.3% vs. 69.6 +/- 6.3%, P = 0.036) and control subjects (30.5 +/- 3.4% vs. 61.7 +/- 6.0%, P = 0.01). However, the decrease in MVA during the hyperinsulinaemic clamp study was more marked in the control subjects than in the diabetic subjects (P = 0.03). A significant positive correlation was found between percentage decrease of MVA and non-esterified fatty acids following the insulin clamp in NIDDM (r = 0.83, P = 0.04). We conclude that acute hyperinsulinaemia decreases cholesterol synthesis less in subjects with NIDDM than in non-diabetic subjects and that this phenomenon, together with increased basal cholesterol synthesis in NIDDM, may in part be due to insulin resistance.
Analysis of Variance↗
Dietary fatty acids and progression of coronary artery disease in men.
We examined associations between dietary fatty acids and progression of coronary artery disease (CAD) in 50 men receiving a lipid-lowering diet or usual care in the St Thomas' Atherosclerosis Regression Study. Nutrient intake was assessed by dietary history and computerized food tables. Progression of CAD over 39 mo, measured by a decrease in minimum absolute width of coronary segments (MinAWS) on angiography, was highly correlated with intakes of palmitic, stearic (18:0), palmitoleic, and elaidic (t-18:1) acids (P < 0.001); no protective effects were found with polyunsaturates. Total saturates and trans unsaturates explained 20% of variance in CAD progression. After adjustment for plasma cholesterol and other risk factors, change in MinAWS was most closely associated with intakes of 18:0 and t-18:1 fatty acids (P = 0.009). We suggest that progression of CAD in men is strongly related to intakes of both long-chain saturates and trans unsaturates, the effects of 18:0 and t-18:1 possibly being independent of plasma cholesterol concentration.
Cholesterol↗
Cerebrotendinous xanthomatosis: a family study of sterol 27-hydroxylase mutations and pharmacotherapy.
We examined the phenotypic characteristics, molecular genetics and optimal pharmacological treatment of cerebrotendinous xanthomatosis (CTX) in an English family with combined hyperlipidaemia. The proband presented in adulthood with classical clinical characteristics of CTX, a greater than tenfold elevation in plasma cholestanol and combined hyperlipidaemia. His brother also had typical features of CTX without the presence of dyslipidaemia. Genotyping revealed that the two brothers were compound heterozygotes for a novel missense mutation in exon 2 (R94Q) and for a recently described nonsense mutation in exon 5, of the sterol 27-hydroxylase gene (CYP27). Analysis of all available family members revealed that hyperlipidaemia did not co-segregate with the presence of a CYP27 mutant allele. Trial of therapy showed that the lowest plasma sterol and triglyceride concentrations and cholestanol:cholesterol ratio were achieved with the combination of chenodeoxycholic acid (CDCA) 750 mg/day, a primary bile acid, and simvastatin 40 mg/day, an inhibitor of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase. CDCA alone and simvastatin alone significantly lowered plasma cholestanol concentration, but the decrease was greater with the former. After 1 year there was significant improvement in both cognitive and motor function with regression of tendon xanthomata on computerized tomography. We conclude that CTX in this English pedigree is probably due to compound mutant alleles in CYP27, that combined hyperlipidaemia in this family is unrelated to CTX, and that this complicated condition responds optimally to the combination of CDCA and simvastatin.
Adolescent↗
Lipid-lowering trials in the primary and secondary prevention of coronary heart disease: new evidence, implications and outstanding issues.
Clinical, angiographic and ultrasonographic data from new trials of the primary and secondary prevention of atherosclerosis and coronary artery disease with lipid-lowering therapy are reviewed. In the West of Scotland Coronary Prevention Study pravastatin significantly decreased cardiovascular events in asymptomatic men with moderate hypercholesterolaemia without increasing noncardiovascular mortality. The favourable effects of pravastatin may also extent to carotid arteries. Preliminary data from the Cholesterol and Recurrent Events Study testify to the value of lowering cholesterol in patients with near normocholesterolaemia and established coronary artery disease. New angiographic and ultrasonographic studies concur with findings of previous trials and indicate that the benefits of statins extend to noncoronary vascular beds. Meta-regression analysis of angiographic trials shows that optimal treatment for regression of coronary artery disease should aim for an LDL-cholesterol of approximately 3.0 mmol/l. The value of regulating high plasma triglyceride and low HDL-cholesterol has been emphasized by a bezafibrate study. Angiographic trials also suggest that aggressive pharmacotherapy may match the beneficial effects of LDL apheresis in heterozygous familial hypercholesterolaemia. Post-hoc analyses from previous angiographic trials have provided new hypotheses for future studies. The implications of the new evidence presented is examined, as well as issues of cholesterol screening and the economics of treatment.
Anticholesteremic Agents↗
Prevalence of microalbuminuria, lipoprotein (a) and coronary artery disease in the lipid clinic.
AIMS: To assess the prevalence of microalbuminuria (MA) and elevated serum lipoprotein (a) (Lp (a)) concentration, and their association with coronary artery disease (CAD) and other conventional cardiovascular risk factors in non-diabetic patients attending a lipid clinic. METHODS: Clinical details were obtained from 96 consecutive non-diabetic patients from whom a fasting blood sample was taken to measure serum lipid, lipoprotein, apolipoprotein and plasma glucose, urea, and electrolyte concentrations. The urine albumin/creatinine ratio (Ua/Uc) was estimated from a random clinic sample. RESULTS: Of the patients, 26% had MA (defined as a Ua/Uc > 2.2 mg/mumol), 38% had an elevated Lp (a) concentration (defined as > 0.4 g/l), 36% were hypertensive (blood pressure > 160/95) or were taking antihypertensive medication, and 25% had established CAD defined on clinical criteria. In men the Ua/Uc ratio was highly associated with age, plasma low density lipoprotein cholesterol, and triglyceride concentrations. In women there was no association between the Ua/Uc ratio and variables examined. Lp (a) concentration was not associated with variables examined in either sex. In multiple logistic regression analysis adjusted for age and sex, serum Lp (a) concentration, diastolic blood pressure and treatment of hyperlipidaemia were highly associated with CAD. MA was not, however, associated with CAD. CONCLUSIONS: MA is common in a lipid clinic and is more likely to be found among older male patients with hyperlipidaemia. However, in contrast with Lp (a) concentrations, MA is not a risk factor for CAD in this high risk population. Lp (a) concentration may be a useful tool in the lipid clinic, but there does not seem to be a justification for measuring the Ua/Uc ratio, at least in non-diabetic subjects.
Aged↗
Serum lipid, lipoprotein and apolipoprotein changes in gestational diabetes mellitus: a cross-sectional and prospective study.
AIMS: To compare serum lipid, lipoprotein and apolipoprotein concentrations during and six to 12 months after pregnancy in control and diabetic women. METHODS: The serum lipid, lipoprotein and apolipoprotein concentrations were measured in 20 women with gestational diabetes mellitus (GDM) and 22 women with normal glucose tolerance (controls) during the third trimester of pregnancy and six to 12 months after delivery. RESULTS: During pregnancy the women with GDM had higher serum triglyceride (mean (95% confidence interval (CI)), 2.91 (2.22-3.51) v 2.1 (1.75-2.52)) but lower low density lipoprotein (LDL) cholesterol concentrations compared with controls (mean (SD), 3.08 (1.2) v 4.01 (1.1). Total cholesterol, high density lipoprotein (HDL) cholesterol and apolipoprotein concentrations were not significantly different between the two groups. After pregnancy, total cholesterol, HDL cholesterol, triglyceride, and apolipoprotein A1 and B decreased in a parallel manner, resulting in lower concentrations, comparable between the two groups. LDL cholesterol concentrations decreased after pregnancy in the controls (mean (SD), 4.01 (1.1) v 2.69 (0.6)) but not in those with GDM (3.08 (1.2) v 2.72 (0.7)). The change in lipid concentrations was not related to change in weight. CONCLUSION: Development of diabetes during pregnancy induces a state of dyslipidaemia characterised by elevated triglyceride concentrations, as seen in other insulin resistance states. However, GDM seems to blunt the increase in LDL cholesterol during pregnancy and this requires further investigation. Whether the changes in lipoprotein metabolism in GDM are significant for the health status of the mother and the foetus requires further study.
Adult↗
Role of cholesterol in regulating apolipoprotein B secretion by the liver.
The review examines the evidence that the supply of cholesterol available for incorporation into nascent lipoprotein particles exerts a regulatory influence on apolipoprotein (apo) B secretion by the liver. Support for this hypothesis comes both from in vitro experiments and from recent observations in normal subjects and patients with dyslipidemia associated with familial hypercholesterolemia, obesity, noninsulin dependent diabetes mellitus, growth hormone deficiency and cholesteryl ester storage disease. The findings do not negate a role for triglyceride synthesis in determining apoB secretion in very low density lipoprotein, but the inhibitory effects on the latter process of pharmacological blockade of cholesterol synthesis or esterification suggest that it is conditional upon an adequate supply of cholesteryl ester.
Acyl Coenzyme A↗
Serum HDL cholesterol: should it be routinely measured?
HDL cholesterol is only one of many risk factors which can be used to predict coronary disease events, and the relationship between the benefits of lipid-lowering strategies and changes in HDL levels is, at present quite unclear.
Cholesterol, HDL↗
Angiotensin converting enzyme gene polymorphism and the course of angiographically defined coronary artery disease.
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Arteriosclerosis↗
Familial Hypercholesterolaemia Regression Study and its implications.
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Anticholesteremic Agents↗