Continuous blood glucose monitoring and characteristics of diabetes in patients on maintenance haemodialysis treatment

The glucose metabolism of diabetes mellitus during maintenance haemodialysis treatment was studied in four patients with endstage renal failure. There was a large day-to-day variation in the predialysis blood glucose levels, which it was difficult to control by adjusting the insulin dose. In spite of very high blood glucose levels, blood lactate and beta-hydroxybutyrate were not elevated. Triglycerides were markedly and constantly elevated, in no apparent association with the predialysis blood glucose level. The patients were shown to release moderate amounts of glucose, beta-hydroxybutyrate and lactate into the dialysate during the dialysis period. A technique of continuous blood glucose monitoring during the haemodialysis period was applied. With this technique blood sugar levels were accurately determined during the whole dialysis period. A rapid drop in the blood glucose level was found in apparent association with an aggravation of symptoms. A very marked tendency to hypoglycaemia was also revealed. It is concluded that the technique is a valuable aid in the proper management of diabetes in these cases.

Biochemical studies on glomerular basement membrane in human diabetic microangiopathy

Biochemical modifications of glomerular basement membrane (GBM) in diabetes mellitus have been investigated in human subjects. Amino acid analysis and electrophoretic study of unfractioned GBM from diabetic and non diabetic kidneys showed an increase in hydroxylysine, hydroxyproline and glycine and in the glycosylgalactosyl-hydroxylysine (G-G-H) content of diabetic GBM. A decrease in 1/2 cystine was also demonstrated in diabetes. Fractionation of GBM showed the increase in G-G-H observed on unfractioned GBM to reflect a quantitative increase of the "collagen" fraction in diabetes, the amino acid composition of this fraction remaining unchanged. The decrease in 1/2 cystine demonstrated on unfractioned GBM was located in the non collagenous fractions of this structure.

Hormonal profile, blood sugar control and HLA patterns in long-term insulin dependent diabetes with and without vascular disease

Nineteen insulin dependent diabetics with onset at 30 years of age or less and duration of diabetes of greater than 25 years were divided into two groups on the basis of the presence or absence of clinically evident vascular disease. The patients without vascular disease were characterised by a later mean age of onset, lower fasting growth hormone concentration, and a lower frequency of the unusual HLA pattern B8 without A1 compared to the diabetics with vascular complications. The level of blood glucose control assessed over the last 15 years, insulin antibody titres, plasma glucagon levels and plasma cholesterol did not differ between the two groups. Residual beta cell activity was found in only one of the 19 patients. Although this study does not exclude an effect of the degree of blood glucose control or persistence of beta cell function in the early stages of diabetes on the subsequent development of vascular disease, it suggests that genetic factors, age of onset and plasma growth hormone levels may be more important.

[Metabolism of capillary endothelium tissue and its abnormalities in diabetes mellitus (author's transl)]

Glucose is the major energetic substrate of blood capillary endothelium; aerobic glycolysis is quantitatively the most important pathway. Insulin has no direct effect on glucose utilization. The glucokinase activity of the capillary endothelium is undetectable and the plasma cell membrane is freely permeable to glucose. All pathways of glucose utilization are stimulated by a high ambient glucose concentration: intracellular sorbitol accumulation and glucose-carbon incorporation into basement membrane collagen are most sensitive to the glucose effect. During chronic hyperglycemia, the amino acid composition of the basement membrane is modified and its capacity to incorporate glucose is enhanced. The glucose induced alterations of the blood capillary metabolism may contribute to the development of the diabetic microangiopathy.

Diabetic microangiopathy. I. Current status of the chemistry and metabolism of the glomerular basement membrane

In recent years, the nature of the renal glomerular basement membrane has been the subject of numerous investigations. In diabetes mellitus, the renal glomerulus is characterized primarily by thickening of the basement membrane and excessive accumulation of basement membrane-like material in the mesangial region. Compositional analyses have shown that basement membranes are glycoprotein in nature. Studies of the glomerular basement membranes in diabetes have indicated a change from normal chemical composition. Furthermore, studies of the metabolism of diabetic kidneys in experimental animals, using cortical homogenates and isolated glomeruli, have demonstrated higher anabolic and lower catabolic enzyme activities. However, contradictory data have been reported with regard to both the chemical composition and metabolism of the kidney in human and experimental diabetes. This review attempts to examine these reports in detail and discuss the possible causes for these discrepancies.

Unconjugated estriol and 15alpha-hydroxyestriol in complicated pregnancies

Simultaneous determinations of unconjugated estriol and 15alpha-hydroxyestriol (E4) levels in maternal serum were studied serially to ascertain the relative usefulness of these estrogens as indicators of fetal welfare. Complicated pregnancies included 16 patients with pre-eclampsia and/or hypertension, six patients with severe Rh-isoimmunization, 12 patients with diabetes mellitus, of which four had vascular disease, three patients with fetal death in utero, and three twin pregnancies. Retrospective analysis failed to indicate a clinically useful role for serum E4 determinations in the evaluation of fetal welfare during high-risk pregnancies.

Diabetic control and the late complications of diabetes

Considerable evidence points to a metabolic cause for the long-term complications of diabetes--neuropathy, retinopathy, nephropathy and atherosclerosis. Recent studies suggest potential benefits from controlling hyperglycemia as well as possible. However, the individual physician must analyze the evidence for himself and then decide on which principles to base the treatment of his patients.

Metabolic approaches to studies on diabetic microangiopathy

The chief purposes of this report are (a) to focus attention on various metabolic and pathophysiologic parameters relating prostaglandins (PGs) and thromboxanes to the slow but inexorable progression of vascular and blood cell dysfunction in diabetes mellitus and (b) to suggest areas of investigation that may be of fundamental importance for expanded areas of diabetes research. The prime thrust of these investigations would be to correlate these metabolic and pathophysiologic parameters with the vasculopathy of diabetes mellitus.

The association between serum triglycerides and gamma glutamyl transpeptidase activity in diabetes mellitus

A study conducted on 228 diabetic patients has shown a significant positive association between serum gamma-glutamyl transpeptidase (GGT) and triglyceride levels. Both fall with treatment, the most marked reduction occurring in patients on insulin. We suggest that the association between serum GGT and triglyceride levels and also the higher incidence of raised GGT and triglyceride levels in new diabetics may reflect hepatic microsomal enzyme induction of the rate-limiting enzymes of triglyceride synthesis. Serum GGT does not seem to correlate with hepatomegaly in diabetes mellitus.

Glucose intolerance, diabetes mellitus and atherosclerosis; prospects for prevention

Increased prevalence and incidence of arterial disease has become the major cause of disability and death in diabetics in Western cultures—but is much less common among Japanese and African diabetics. In the West, the presence of lesser, ‘subdiabetic’ degrees of glucose intolerance are probably independent ‘risk factors’ for accelerated atherosclerosis. Although many explanations for the link have been advanced—among them direct effects of glucose and insulin on the arterial wall, less direct effects of circulating lipoproteins, abnormalities of blood clotting and fibrinolysis and elevated blood pressure, even the influence of antidiabetic treatment itself—none has been clearly established. Nevertheless there is scope and hope that appropriate measures may reduce the raised arterial disease risk in the diabetic.

[Diabetic nephropathy (author's transl)]

The term diabetic nephropathy includes the Kimmelstiel-Wilson intercapillary glumerulosclerosis (1936), arterio-arteriolosclerotic changes and pyelonephritis. In principle, diabetic nephropathy becomes more frequent with increasing duration of diabetes mellituus. Pyelonephritis is 4 to 5 times more frequent in diabetics than in the general population. Elderly overweight women are particularly at risk. - Only the nodular intercapillary glomerulosclerosis and not the diffuse or exudative form is specific for diabetes mellitus. It is found in 20-40% of all diabetics who have had the disease for 10-15 years. Whether the microangiopathy is typical of diabetes mellitus remains to be seen. Due to the intense cardiovascular changes, possible disorders of brain and liver function and infection, the prognosis of renal insufficiency is considerably worse in diabetics than in non-diabetics.

Wound healing: a model for the study of diabetic angiopathy

Wound healing as a model for diabetic angiopathy has been studied by light and electron microscopy. Biochemical studies of the rate of incorporation of 3H-proline and 3H-thymidine into collagen and DNA, respectively, have confirmed the morphologic observations. In both the normal and the diabetic, there was a marked decrease in the rate of collagen and DNA synthesis, suggesting that most of the cells in the biopsies were stunned by the injury and ceased DNA replication during the initial phase. In control mice this decrease was followed by a modest but significant burst of DNA replication, which peaked at two hours and by the fourth hour had returned to the one-hour level. In the diabetic this burst of DNA replication was absent and no capillary morphogenesis was seen at two, four, and eight hours. At 16 hours, there were only a few abnormal nascent vessels observed in the diabetic and antiserum-treated mice. The peak in the rate of collagen synthesis at four hours correlated well with the condensation of collagen at the wound margin and the fibroblast rough-endoplasmic-reticulum (RER) proliferation. In the diabetic mice, there was a significantly attenuated rate of collagen synthesis for the entire 16-hour period. The lack of DNA replication, capillary morphogenesis, fibroblast RER proliferation, and decreased collagen synthesis in the diabetic mouse can be considered interrelated and significant factors in the diabetic's impaired response to cellular injury. In view of the increased frequency and severity of injury to the circulation of the diabetic and the impaired response to repair such injury, it is likely that wound healing is a promising model for diabetic angiopathy.

Growth hormone's role in diabetic microangiopathy

The state of the blood vessels is normal at the clinical onset of juvenile diabetes. Vascular changes develop slowly and progressively. According to the growth hormone hypothesis, elevated serum growth hormone is one casual factor in the development of diabetic angiopathy. The hypothesis proposes an effect of growth hormone not on blood glucose but directly on blood vessels. This hypothesis is based on serum growth hormone studies and on a controlled clinical trial of the effect of hypophysectomy on small blood vessels. An animal model of large-vessel disease in diabetes is briefly described. There is a large molecule in diabetic serum causing proliferation of aortic myomedial cells in culture. Growth hormone causes a similar proliferation. A short summary is given of the present situation in somatostatin research relating to diabetes mellitus.

Plasma protein changes, blood viscosity, and diabetic microangiopathy

Diabetic microangiopathy is a slowly progressive condition that usually manifests itself years after the onset of the carbohydrate-metabolism disturbance. It is a far more striking problem in some diabetics than in others. Differences in the pattern of its effect in several body systems suggest that the local vascular disturbance is a mixture of a general microcirculatory change in diabetes and a specific vascular alteration in each tissue. Its manifestations in the individual diabetic appear to be influenced by both elements. Evidence is presented that plasma protein changes in diabetes and their effects on blood flow play a role in acclerating the rate of progression of diabetic microangiopathy by raising plasma viscosity and by increasing the affinity of erythrocytes for each other. The plasma protein change is dominated by a possibly hormonally mediated pattern of alpha-globulin elevation seen in many chronic disorders. This elevation of acute-phase proteins is not likely by itself to produce diabetic microangiopathy, but it may cause an additional stress on the metabolically disturbed diabetic microcirculation. The basic change is a disturbance in the average molecular shape of the plasma proteins that both directly increases plasma viscosity and enhances the aggregation of erythrocytes. Studies are now in progress to determine which of these two mechanisms is more likely to be important in accelerating the development of diabetic microangiopathy.

Quantification of collagen in renal glomeruli isolated from human nondiabetic and diabetic kidneys

Previous studies of diabetic renovascular complications have measured morphologic changes in relatively few glomerular vessels by electron microscopy. The present study samples 20,000 to 80,000 glomeruli from each of ten nondiabetic and ten diabetic age- and sex-matched subjects. Glomeruli were isolated and fractionated by size with a sieving method. Three samples of glomeruli from each subject were analyzed for size, mass, and hydroxyproline content as an index of basement membrane collagen. Approximately 40 per cent of the glomeruli in each sample were isolated. Glomeruli comprised 94 per cent of the tissue elements present, and 92 per cent of the isolated glomeruli were intact. Diabetic glomeruli are larger than nondiabetic glomeruli (mean diameter +/- S.E.M. = 258 +/- 10 mu versus 196 +/- 6 mu) and heavier (499 +/- 63 ng. versus 232 +/- 16 ng.). Diabetic glomeruli have greater hydroxyproline content than nondiabetic glomeruli when content is expressed per glomerulus (21.9 +/- 3.3 ng. versus 7.1 +/- 0.5 ng.) and when expressed per milligram dry weight of glomeruli (44.0 +/- 2.4 mug. versus 31.6 +/- 1.9 mug.). Glomeruli from diabetics of longest duration show the greatest increases in mass and hydroxyproline values. A pathologist's semiquantitative estimation of diffuse glomerulosclerosis revealed a high correlation between hydroxyproline values and histologic determination of the extent of the renal lesion. These measurements allow quantification of basement membrane collagen and may be used to follow development of diabetic vascular complications.

[Somatotropic hormone before and after treatment of microangiopathies in diabetes mellitus patients]

Patients (41) suffering from diabetes mellitus complicated by microangiopathies aged from 16 to 72 years were examined; diabetes of moderate severity was diagnosed in 20 patients (the I group), and severe-in 21 (the II group). Basic STH level after L-DOPA oral loading was studied in 60 and 90 minutes in all of these patients, and ti proved to be elevated in both groups. Following L-DOPA loading the peak of increase in the first group was found on the 60th minute, and in the II group-on the 90th minute. Basic STH secretion diminished in 16 patients after anginin treatment; this could apparently be attributed to improvement in the function of the hypothalamohypophysial system.

Renal glucose utilization in genetically diabetic microangiopathy

Glucose uptake into kidney tissue is not influenced by the development of glomerulosclerosis in KK mice. Glucosyltransferase activity remains at a normal level even at an age having a highest incidence of serious development of glomerulosclerosis. The observation suggests that biosynthesis of basement membrane reflected by its glucosyltransferase activity does not accelerate in genetically transmitted microangiopathy.

On fibrinolysis in diabetes mellitus

In diabetics, irrespective of age at onset and standing of the disease, the fibrinolytic activity in the blood is decreased, most markedly in obese patients and in those with angiopathy. In this investigation we found--significantly more often than in controls--a low release of the plasminogen activator to the blood from the endothelial cells, and also in one fourth of the diabetics an abnormally low activator activity of the vessel walls. These changes, as well as the significantly elevated levels of inhibitors of the fibrinolytic activity, will impair removal of fibrin deposits and possibly contribute to the development of vascular lesions.

Diabetic retinopathy and the fibrinolytic system

We found that patients with long-standing (greater than 10 years) diabetes who have not developed retinopathy had a significantly higher and almost normal fibrinolytic response to venous occlusion and also a higher spontaneous fibrinolytic activity than those who had developed retinopathy. In the latter, the low fibrinolytic activity of the blood was, however, not correlated to a low plasminogen activator activity of the vessel walls. Although generally lower than in controls, the activator activity of the vessel walls in the retinopathy group tended to be higher than in the rest, and in fact those with only minor vascular changes (microaneurysms) had a significantly higher activity than the other diabetics. The fibrinogen and alpha2-macroglobulin levels were higher in the retinopathy group. Thus multiple abnormalities of the fibrinolytic system were found to be related to diabetic microangiopathy.

Diabetic microangiopathy

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