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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

On the basis of studies in monkeys, the hypothesis has been proposed that vasectomy induces the formation of circulating immune complexes (CICs), which--via activation of the complement system--may result in immune injury of the endothelium and thereby exacerbate atherosclerosis; the same mechanism has been suggested to cause retinal arteriolar changes in vasectomized men. We compared 46 men, 5 years after vasectomy, with 46 age-matched control subjects and found no difference in the distribution of arteriolosclerotic retinopathy gradings evaluated by ophthalmoscopy and fundus photography. Blood samples from the two groups were collected and handled identically, and no significant difference in activity was found in four different tests for CICs and two tests for split products of complement factor C3. Thus, the results do not support the hypothesis that changes mediated by CICs occur in vessels after human vasectomy.
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PMID:No increase in arteriolosclerotic retinopathy or activity in tests for circulating immune complexes 5 years after vasectomy. 708

In 70 patients with juvenile-onset, insulin-dependent (type I) diabetes and 75 age- and sex-matched controls the reversible platelet aggregates expressed as platelet count ratio (PCR) and the ADP-induced platelet aggregation were studied. Retinal microangiopathy was staged by retinal fluorescein angiography. The mean PCR of the patients (0.82 +/- 0.02) was statistically significantly lower than that of the controls (0.97 +/- 0.01). However, in different stages of retinopathy no significantly different PCR could be observed. ADP-induced platelet aggregation (0.5 and 1.0 micromol/l) exhibited a higher reactivity of diabetic platelets, but with the exception of tangent alpha (see later), the differences were not statistically significant in comparison to the controls. After collagen-induced platelet aggregation (0.5 and 1 microgram/ml) the lag time in diabetics was significantly (p less than 0.001) lower than in the controls, whereas the other quantitative parameters exhibited higher platelet reactivity in general, though not statistically significant. No relationship between PCR and the in vitro induced aggregation was found. The degree of retinopathy had no significant influence on platelet aggregation. In general, the data demonstrate an increase in sensitivity of platelets in juvenile-onset diabetics, whereas no influence of stage of microangiopathy could be detected.
Atherosclerosis
PMID:Platelet aggregation and reversible platelet aggregates in type I-diabetes staged by retinal fluorescein angiography. 728 54

Thrombosis is a well-recognized complication of atherosclerosis and may be a factor in initial lesion formation. Experimental endothelial cell injury results in activation of the coagulation mechanism and therefore may be a critical aspect of the pathogenesis of occlusive vascular disease. If this is so, then risk factors for atherosclerosis should affect the endothelium either by causing cell injury, inhibiting repair mechanisms, or altering its thromboresistant properties. To test this, we studied the effect of several risk factors on endothelial cell behavior in vitro. Since the smooth muscle cell is the major cellular component of human atherosclerotic plaque and since a primary smooth muscle cell lesion is suggested by the clonal nature of human plaque, we also studied the effect of risk factors on arterial smooth muscle behavior. We have found that homocysteine directly injures human endothelium, which may account for the premature arterial disease in homocystinuria. Serum from patients with familial hypercholesterolemia inhibits the critical function of endothelial cell migration, as well as arterial smooth muscle cell migration. Moderate hypoxia has no effect on endothelial cell or smooth muscle cell viability, proliferation, or migration. Platelet factors are shown to affect human smooth muscle cell proliferation and both endothelial cell and smooth muscle cell migration. Preliminary study of platelet activation in diabetes with retinopathy suggests a relation to glucose control, but might reflect underlying vessel disease rather than direct platelet effect.
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PMID:Studies on the cellular basis of atherosclerosis: the effects of atherosclerosis risk factors on platelets and the vascular endothelium. 729 72

Patients suffering from the severe complications associated with both insulin- (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM): nephropathy, retinopathy, neuropathy, and atherosclerosis are still largely left without a prospect of an efficient treatment. This is the case even if it has been assumed for decades and now finally proved by the results from the Diabetes Control and Complications Trial (DCCT) that hyperglycemia is the single main cause of these complications. Improved glycemic control as a result of intensive insulin treatment has the potential to reduce the incidence and progression of complications, but implementation and monitoring of improved glycemic control in all groups of IDDM and NIDDM patients in different communities will be difficult and expensive. Results from the recently terminated DCCT have shown that even with intensive insulin treatment, there will be a significant burden of complications on the diabetic population. It will, therefore, still be of immense importance for the long-term quality of life for the diabetic patient that additional possibilities are developed for prevention and intervention against diabetic complications. Almost two decades of research, animal model testing, and clinical trials have been conducted on various efficient aldose reductase inhibitors. Now the concept of inhibition of formation of advanced glycosylation endproducts on proteins and lipids resulting from extra- and intracellular hyperglycemia is entering the scene as an alternative or perhaps supplementary approach to reduce the occurrence of diabetic complications. An overview of the results from these two fields of research and associated drug-development programs will be presented along with thoughts on possible future developments.
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PMID:Diabetic late complications: will aldose reductase inhibitors or inhibitors of advanced glycosylation endproduct formation hold promise? 759 49

The prevalence of diabetic microangiopathy (retinopathy, microalbuminuria, and neuropathy) and macroangiopathy (ischemic changes in EKG) in patients with diabetes mellitus was compared between patients newly found on occasion of mass-screening without any symptoms and signs in Funagata, Japan, and patients who visited the outpatient clinic of our university hospital. The mean fasting blood glucose level in the Funagata group was lower, and the mean duration of diabetes was shorter. The prevalence of every microangiopathic complication was significantly lower in the Funagata group than in the outpatient clinic group. However, the prevalence of ischemic changes in EKG was not different between the two groups. The conclusion that prevalence of diabetic microangiopathic complications was primarily related to the degree and duration of hyperglycemia seemed to be in accordance with the results of the Diabetes Control and Complications Trial (DCCT). The role of hyperglycemia for pathogenesis of macroangiopathy and atherosclerosis has been controversial. Not only hyperglycemia but also hypertension, dyslipoproteinemia, and other factors due to insulin resistance resulting from visceral fat syndrome, might be responsible for the occurrence of atherosclerosis.
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PMID:[Risk factor: diabetes mellitus]. 769 23

The reactive vascular-injuring amino acid homocysteine was previously shown to be increased in plasma in diabetic patients with clinical signs of nephropathy. In this study, plasma homocysteine was measured in type 1 diabetic patients with normoalbuminuria (n = 22), microalbuminuria (n = 40) and proteinuria (n = 14) in order to investigate whether plasma homocysteine levels are increased already at the stage of incipient nephropathy, i.e. microalbuminuria. Furthermore, patients were characterized according to the degree of retinopathy. Plasma homocysteine in the whole population (n = 76) was related to B-Folate (r = 0.38, p < 0.01), S-Creatinine (r = 0.55, p < 0.001), S-Urea (r = 0.37, p < 0.01), U-Albumin (r = 0.46, p < 0.001), urinary N-acetyl-beta- glucosaminidase (r = 0.40, p < 0.001), systolic blood pressure (r = 0.36, p < 0.01) and diabetes duration (r = 0.44, p < 0.001). There were no differences in plasma homocysteine levels between patients with normoalbuminuria (8.0 +/- 1.7 mumol l-1; mean +/- SD) and those with microalbuminuria (9.1 +/- 3.4 mumol l-1). However, patients with clinical signs of nephropathy had higher plasma homocysteine levels (12.9 +/- 5.7 mumol l-1, p < 0.01) compared to the other two groups. There was no association between plasma homocysteine levels and different degrees of retinopathy. Thus, the present study does not show any relation between plasma homocysteine levels and early stages of diabetic nephropathy or retinopathy indicating that elevated concentrations of plasma homocysteine does not explain the increased risk for atherosclerosis observed in patients with microalbuminuria.
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PMID:Lack of association between plasma homocysteine levels and microangiopathy in type 1 diabetes mellitus. 770 67

The Diabetes Control and Complications Trial (DCCT), a multicenter, randomized, controlled clinical trial, demonstrated that intensive diabetes therapy delays the onset and slows the progression of retinopathy, nephropathy, and neuropathy in patients with insulin-dependent diabetes mellitus. This study presents the effect of intensive therapy on atherosclerosis-related events and associated risk factors. Patients (n = 1,441) between the ages of 13 and 39 years with insulin-dependent diabetes mellitus were randomly assigned to conventional or intensive diabetes treatment. The patients were free of cardiovascular disease at baseline. Patients with hypertension, hypercholesterolemia, or obesity were excluded. Average length of follow-up was 6.5 years (range 3.5 to 9). The study used standardized definitions of macrovascular events, verification of such events, and central laboratories for determination of lipids and the grading of electrocardiograms. The number of combined major macrovascular events was almost twice as high in the conventionally treated group (40 events) as in the intensive-treatment group (23 events), although the differences were not statistically significant (p = 0.08). There were no differences in the cumulative incidence of hypertension. Mean total serum cholesterol, calculated low-density lipoprotein cholesterol, and triglycerides were significantly reduced in the intensive-treatment group (p < or = 0.01), as was the development of low-density lipoprotein cholesterol levels > 160 mg/dl. Weight gain was significantly increased in the intensive-treatment group (p < 0.001). There were no differences in cigarette smoking habits, consumption of alcohol, or aspirin use between treatment groups. The reduction in some, but not all, cardiovascular risk factors suggests a potential beneficial effect of intensive therapy on macrovascular disease in insulin-dependent diabetes mellitus.
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PMID:Effect of intensive diabetes management on macrovascular events and risk factors in the Diabetes Control and Complications Trial. 773 97

The clinical studies have demonstrated that patients showed significant improvements in their oxidative status after 3 months treatment. This improvement in oxidative status which was associated with a reduction in platelet reactivity, remained constant for the rest of the study period. The effect was independent of glycaemic control. The demonstration of a benefit to clinical vascular disease has proved difficult to achieve in all studies of non-insulin dependent diabetes. This is due to the multifactorial nature of complications and the long duration of disease required before microvascular complications such as retinopathy became apparent. The Japanese Diabetic Retinopathy Program24 studied the progression of retinopathy over a 5 year period comparing Gliclazide with other sulphonylureas and with placebo. The study suggested that with equivalent metabolic control there was a trend towards a lower rate of deterioration of retinopathy and a significantly lower incidence of pre-proliferative retinopathy in the group receiving Gliclazide compared with patients receiving other sulphonylureas or placebo. There is little comparative evidence on the effect of specific sulphonylureas on large vessel disease. Although improvement in parameters of hyperglycaemia is associated with an improvement in morbidity from large vessel disease. In Type II diabetes atherosclerosis coexists in the majority of patients and often predates the clinical diagnosis of diabetes. The presence of atherosclerosis which often determines the ultimate fate of the patient, further increases the level of lipid peroxidation of oxidative stress, amplifying the effects of hyperglycaemia and potentiating vascular damage. In diabetes, therefore where increased glycation and oxidation are fundamental in the pathogenesis of diabetic vascular disease agents such as Gliclazide with anti-oxidant activities may have an enhanced therapeutic role.
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PMID:The potential of gliclazide, a sulphonylurea to influence the oxidative processes within the pathogenesis of diabetic vascular disease. 777 Dec 62

Morbidity and mortality through coronary atherosclerosis are higher in Type 2 diabetic patients than in nondiabetic subjects, roughly by a factor of 2 in males and 3 in females. Methodological problems in attempting to weigh the relative effects of each factor make it difficult to accurately interpret the numerous epidemiological data already available. Three issues are discussed here:--Do diabetics have more "classic" risk factors than nondiabetics? The incidence of hypertension, lipid disorders, and even smoking is practically consistently higher in diabetics, with "diabetic" lipid disorders (decreased HDL cholesterol and hypertriglyceridemia) topping the list.--Do diabetics have specific risk factors which could explain the observed increase in coronary morbidity and mortality? The answer would appear to be yes, as patent microalbuminuria--between 30 and 300 mg/24 hours--is found, as well as retinopathy and an increase in fibrinogen and PAI1 plasminogen activator inhibitor. Recent genetic studies have highlighted the role of Lp (a), and particularly that of angiotensin converting-enzyme gene polymorphism (DD allele).--What are the respective roles of hyperglycalmia and elevated levels of circulating insulin? In contrast to the importance of insulin in nondiabetics as demonstrated in longitudinal studies, insulin appears to play a marginal or even nil role in diabetics once the disease is established. It is probably glycaemia itself which remains the fundamental factor, even though the mechanisms leading from hyperglycemia to macrovascular complications remain unknown.
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PMID:[Cardiovascular risk factors in type 2 diabetes]. 782 79

Patients with type II diabetes commonly die from thrombotic vascular disease. Large vessel occlusion due to thrombosis or atherosclerotic stenosis is a process accelerated by diabetes and results in premature death. Diabetic small vessel disease, with its unique microangiopathic process, underlies many of the large vessel changes as well as causing retinopathy and nephropathy. The microangiopathic changes produce a prothrombotic tendency that has been widely reported in type II diabetes. There is reduced endothelial cell production of prostacyclin and the activators of fibrinolysis, together with increased platelet reactivity. In addition, there is increased lipid peroxidation and oxidative stress due to excess free-radical activity and impaired antioxidant defenses particularly in the presence of microvascular disease. The development of many of these abnormalities is associated with poor long-term glycemic control. However, the changes are also seen in atherosclerosis in nondiabetic patients where the progression of the disease can be modified by antiplatelet agents and antioxidants. The process of vascular damage is accelerated by diabetes, often due to co-existing disease and aging, although it is not clear that improvement in long-term glycemic control by lowering blood glucose levels to near to the nondiabetic state reduces the development of small and large vessel disease. Although the biochemical mechanism underlying this observation remains uncertain, protein glycosylation and increased platelet reactivity are implicated and interrelated. Increased oxidative stress due to excess free-radical activity may be central to diabetic vascular disease as endothelial cell damage, lipoprotein oxidation, modification of both platelet reactivity and arachidonic acid cascade are all properties of free radicals and their reaction products lipid peroxides.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:From hemobiology to vascular disease: a review of the potential of gliclazide to influence the pathogenesis of diabetic vascular disease. 783 98


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