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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report on clinical and metabolic studies of a newly delineated lipomatosis, characterised by an abnormal mediastinal and abdominal accumulation of fat, without obesity. The clinical features, which occurred in all the patients studied, are: Exertional dyspnoea due to a space-occupying mediastinal accumulation of fat, without evidence of cardiac or pulmonary disease. A pseudo-ascitic abdominal enlargement, due to intra- and retroperitoneal accumulation of fatty tissue. Insulin-independent diabetes mellitus. Type IV hyperlipidaemia and elevated levels of plasma uric acid were observed in four patients. Intra-abdominal lipomatous tissue, obtained during laparoscopy from four patients, demonstrated a reduced lipolytic response to beta-adrenergic stimulation. Thus, fat deposition in the abdominal and mediastinal areas could be causally related to defective lipid mobilization in lipomatocytes. Lipoprotein lipase activity in abdominal adipose tissue were normal in two patients (10.0 and 10.6 nmol/g/min) and markedly elevated in another two patients (37.3 and 49.9 nmol/g/min), as compared with controls (12.7 +/- 2.1 nmol/g/min). When expressed on per cell basis, LPL activity in lipomatous tissue was significantly higher than in control tissue (3.21 +/- 1.1 nmol/10(5) cell/min vs 0.92 +/- 0.16 nmol/10(5) cell/min). Lipoprotein fractionation did not demonstrate consistent modification of the serum lipoprotein pattern. HDL and HDL2 cholesterol values were reduced, even in patients with elevated LPL activity in adipose tissue.
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PMID:Mediastino-abdominal lipomatosis: deep accumulation of fat mimicking a respiratory disease and ascites. Clinical aspects and metabolic studies in vitro. 651 1

Lipoprotein lipase activity of epididymal adipose tissue was measured in streptozotocin-induced diabetic rats. Diabetic rats of 3, 10 and 34 days duration were examined. The enzyme activity in adipose tissue of diabetic rats was similar to that of control rats of the same ages, compared on the tissue weight basis. However, since adipose tissue weight was markedly reduced in rats with both acute and chronic diabetes, total enzyme activity in the whole tissue was very low in such animals regardless of the duration of diabetes. We wish to point out that contradictory results on the adipose tissue lipoprotein lipase activity in diabetic rats in the previous reports have arisen depending on differences in the methods chosen to express enzyme activity.
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PMID:Lipoprotein lipase activity in adipose tissue of streptozotocin-induced diabetic rats. 717 15

Lipoprotein lipase (LPL) activity is reduced in cardiomyocytes from rat hearts following the acute (4-5 day) induction of diabetes with 100 mg/kg streptozotocin. The molecular basis for this inhibitory effect of diabetes on LPL activity was investigated by measuring steady-state LPL mRNA content and the synthesis and turnover of LPL protein ([35S]methionine incorporation into immunoprecipitable LPL protein in pulse and pulse-chase experiments) in control and diabetic cardiomyocytes. LPL activity was reduced to approx. 50% of control in diabetic cardiomyocytes, but LPL mRNA levels and turnover (degradation) of newly synthesized LPL were unchanged. Synthesis of total protein and LPL were reduced to 72% and 71% of control respectively; therefore, relative rates of LPL synthesis were the same in control and diabetic cardiomyocytes. The diabetes-induced reduction in LPL synthesis was accompanied by a decrease in LPL mass to 78% of control, and a decrease in enzyme specific activity (0.48 to 0.33 m-unit/ng of LPL protein) since the decline in catalytic activity was greater than the decrease in LPL synthesis and mass. Thus, post-transcriptional mechanisms involving a reduction in LPL synthesis as part of a generalized decrease in total protein synthesis, together with a post-translational mechanism(s) that result in accumulation of inactive LPL protein, are responsible for the decreased LPL activity in cardiomyocytes from diabetic rat hearts.
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PMID:Post-transcriptional mechanisms are responsible for the reduction in lipoprotein lipase activity in cardiomyocytes from diabetic rat hearts. 764 74

Obesity is associated with dyslipidaemia and increased morbidity and mortality from premature atherosclerosis and diabetes mellitus. Particularly, hypertriglyceridaemia is a characteristic finding in patients with obesity. In addition, the elevated levels of triglycerides may be an important risk factor for development of the obesity-related complications. Lipoprotein lipase activity in skeletal muscle tissue (mLPL) has previously been found to be an important factor regulating the concentration of serum triglycerides. To describe the relationship between mLPL, triglycerides and fatness/fat distribution in more detail we have investigated these parameters under basal conditions and during insulin stimulation in 20 obese females. During hyperinsulinaemia (204 microU ml-1) for 4 h the mLPL activity decreased from 528 +/- 52 nmol FFA g-1 to 412 +/- 44 (P < 0.001). Basal mLPL was negatively correlated with serum triglycerides (r = -0.48, P < 0.05) and positively correlated with HDL-cholesterol (r = 0.58, P < 0.01). Employing multiple variance analysis it was found that both BMI and WHR were negatively correlated to mLPL, however, the impaired lipid profile (high triglyceride, low HDL-cholesterol, high FFA) could only be related to BMI and not to WHR in these obese females. However, reduced insulin-action (insulin resistance) was closely related to abdominal fatness determined by WHR both in relation to the insulin-effect on mLPL as well as for the insulin-effect on whole-body glucose metabolism (clamp-study).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lipoprotein lipase activity in muscle tissue influenced by fatness, fat distribution and insulin in obese females. 850 May 14

Lipoprotein lipase (LPL) is the rate limiting enzyme in the hydrolysis of core triglyceride in chylomicron and very low density lipoprotein (VLDL) thus affecting a broad spectrum of plasma lipid levels. In this paper, we investigated the association of a HindIII polymorphism in the LPL gene with plasma lipid levels and carotid artery wall thickness measured by B-mode ultrasonography. A total of 238 Caucasian subjects were selected from the Atherosclerosis Risk In Community (ARIC) study (male = 1.31, female = 107) based on their fasting triglyceride and LDL-cholesterol levels: normolipidemic (n = 48), hypertriglyceridemic (n = 44), hypercholesterolemic (n = 36), and hypertriglyceridemic-hypercholesterolemic (n = 110) groups. We observed a marginally significant association between lipid phenotypes and HindIII genotypes (P = 0.04) in males, with the hypertriglyceridemic and hypercholesterolemic groups having a higher frequency (0.65) of the H+H+ genotype than the other two groups (pooled: 0.55). In males, there was also a significant association between HindIII genotypes and carotid artery wall thickness after considering the effects of age, body mass index, cigarette smoking, lipid phenotype and diabetes status (P = 0.013), with the H+H+ genotype having a higher average value of carotid artery wall thickness (0.84 +/- 0.15 mm) than the other two genotype groups (0.76 +/- 0.14 mm in H+H(+)-genotype class, 0.75 +/- 0.13 mm in H-H- genotype class). In females, no significant associations among LPL HindIII genotype, lipid phenotype and carotid artery wall thickness were observed. These results suggest that the LPL HindIII polymorphism influences LPL-catalyzed, triglyceride-rich lipoprotein metabolism and carotid artery atherosclerosis in a gender-specific manner.
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PMID:HindIII DNA polymorphism in the lipoprotein lipase gene and plasma lipid phenotypes and carotid artery atherosclerosis. 888 74

Lipoprotein lipase (LPL) is an endothelial-bound enzyme that is rate determining for the clearance of triacylglycerol-rich lipoproteins. Previous studies using rats with streptozotocin (STZ)-induced diabetes have reported inconsistent effects on cardiac LPL activity or immunoreactive protein. To examine the contribution of the severity and duration of diabetes on cellular and heparin-releasable cardiac LPL activity, Wistar rats were administered a high (100 mg/kg; D100) or moderate (55 mg/kg; D55) dose of STZ, and LPL activity was examined at various times after diabetes induction. Heparin perfusion of the isolated Langendorff control heart induced the release of LPL activity as an initial fast phase followed by a slow phase of release. With increasing age, the second phase of LPL release became more pronounced. Severe STZ-induced diabetes reduced heparin-releasable LPL activity by 1 week in the D100 rats. However, in D55 rat hearts, peak heparin-releasable LPL activity was higher than that in control animals at 2 and 12 weeks after STZ injection, with a complete absence of the delayed phase at 12 weeks. The elevated heparin-releasable LPL peak could not be explained by an enhanced LPL synthesis because both cellular and surface-bound LPL activities in myocytes from D55 rats were low, relative to control. Chronic (12-day) insulin treatment of D55 rats prevented the rise in heparin-releasable LDL and the reduction in cell-associated LPL activity. Moreover, acute (90-min) treatment of D55 rats with rapid-acting insulin also reduced the heparin-releasable LPL activity to normal levels, although it had no effect on the low cellular LPL activity. When the heparin-releasable LPL pool was allowed to recover for 1 h after removal of the enzyme, D55 rat hearts continued to demonstrate a higher peak LPL activity after a second heparin perfusion. These studies demonstrate that in moderate but not severe diabetes, there is an augmented peak heparin-releasable LPL activity. Whether or not this enhanced heparin-releasable LPL activity has a pathological role in the diabetic heart has yet to be determined.
Diabetes 1997 Aug
PMID:Differential effects of streptozotocin-induced diabetes on cardiac lipoprotein lipase activity. 923 61

People with non-insulin-dependent diabetes mellitus (NIDDM) have a higher incidence of cardiovascular disease (CVD) than the non-diabetic population. In addition, NIDDM patients have a spectrum of lipid abnormalities that may confer an increased risk of developing CVD. The pattern of dyslipidaemia seen in NIDDM patients is different from that seen in the non-diabetic population. This suggests that patients with NIDDM may need different lipid-lowering treatment from that used in the non-diabetic population. In the post-absorptive state, secretion of very low-density lipoprotein (VLDL) is higher in patients with NIDDM, possibly because of the impaired ability of insulin to inhibit lipolysis and to reduce hepatic VLDL secretion. Clearance of triglyceride-rich lipoproteins is also important in determining the extent of postprandial hyperlipidaemia. Lipoprotein lipase (LPL) reduces plasma lipoprotein concentration via several mechanisms. In patients with NIDDM, the capacity of LPL to minimize postprandial hyperlipidaemia may be reduced, although the pathophysiological basis of this is not known. Other changes in patients with NIDDM, such as modifications to cholesteryl ester transfer protein (CETP) and hepatic lipase activity, may also affect postprandial lipaemia but such effects are probably secondary to alterations in lipoprotein clearance. Present evidence suggests that postprandial hyperlipidaemia is atherogenic. There are, however, little specific data from patients with NIDDM. More studies are therefore needed to establish the optimal treatment of dyslipidaemia in patients with NIDDM.
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PMID:Postprandial lipoproteins in non-insulin-dependent diabetes mellitus. 927 17

Cardiovascular diseases are the leading cause of morbidity and mortality in diabetes. Lipoprotein lipase (LPL), a major secretory product of macrophages, has been suggested to play a key role in the development of atherosclerosis. In the present study, we evaluated the effect of high glucose on macrophage LPL mRNA expression and secretion. Exposure of murine J774 macrophages to high D-glucose concentrations (20-30 mmol/l) resulted in a dramatic upregulation of LPL mRNA expression and immunoreactive mass. This effect was not observed when these cells were incubated in the presence of L-glucose or mannitol. High glucose concentrations were also found to enhance LPL gene expression and immunoreactive mass in human monocyte-derived macrophages. J774 cells cultured in a high glucose environment expressed increased c-fos mRNA levels. Treatment of these cells with c-fos antisense DNA or protein kinase C inhibitor inhibited the stimulatory effect of glucose on LPL mRNA expression. In J774 cells exposed to high glucose concentrations, enhanced nuclear protein binding to the AP-1-responsive region of the murine LPL promoter was observed, while LPL mRNA stability remained unchanged. Overall, these results demonstrate that high glucose upregulates macrophage LPL gene expression and immunoreactive mass and that this effect involves transcriptional events.
Diabetes 1998 Mar
PMID:Stimulatory effect of glucose on macrophage lipoprotein lipase expression and production. 951 50

Insulin Lispro (IL) is a short-acting insulin analog that better reproduces the physiological postprandial insulin profile. The aim of this study was to compare the effects of intensive insulin therapy on lipid metabolism using preprandial IL and regular insulin (RI) in 10 insulin-dependent diabetes mellitus (IDDM) subjects. The mean hemoglobin A1c (HbA1c) at baseline was 7.13% +/- 1.2% and did not change after both treatments. In IDDM patients, total cholesterol and triglyceride levels appeared lower after RI than after IL. The low-density lipoprotein (LDL) to high-density lipoprotein (HDL) ratio significantly decreased only after RI (baseline, 2.01 +/- 0.6; IL, 1.88 +/- 0.6; RI, 1.71 +/- 0.5, P < .05). Although no very-low-density lipoprotein (VLDL) composition abnormalities were observed at baseline, the protein content was lower (P < .05) after IL (8.13% +/- 2.93%) than after RI (11.93% +/- 3.41%). Intermediate-density lipoprotein (IDL) protein depletion at baseline (6.14% +/- 6.84%) was normalized after both treatments (IL, 11.09% +/- 12.14%; RI, 10.38% +/- 16.68%, P < .05). LDL, HDL, HDL2, and HDL3 composition abnormalities were similar after both treatments and did not normalize. IDDM and control subjects showed similar LDL subfraction distribution at baseline and after both treatments. Two-hour postprandial VLDL composition alterations, although improved after RI, completely normalized after IL (P < .05). Lipoprotein lipase (LPL) and cholesteryl ester transfer protein (CETP) activities were similar to the control group and did not change after both treatments. Hepatic lipase (HL) activity was lower in diabetic patients (39.6 +/- 35.2 v 87.0 +/- 27.1 U/L, P < .01) and remained lower after both treatments. In conclusion, in IDDM patients, IL (injected immediately before the meal) may offer small different effects on lipoprotein metabolism versus RI (injected 30 minutes before the meal) that, taken together, do not seem relevant.
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PMID:Effects of a short-acting insulin analog (Insulin Lispro) versus regular insulin on lipid metabolism in insulin-dependent diabetes mellitus. 958 Feb 47

Lipoprotein lipase mass exists in preheparin serum, even though the activity is scarcely found. The implication of this is unclear. We studied the effect of an insulin sensitizer, troglitazone, on this preheparin serum lipoprotein lipase mass (preheparin LPL mass) in non-insulin-dependent diabetes mellitus (NIDDM) patients as well as on serum lipid levels and low density lipoproteins (LDL) particle size. Thirty-one NIDDM patients with poor control were administered troglitazone 400 mg/day. Hemoglobin A1c had significantly decreased (13%, P < 0.001) 2 months later. Preheparin LPL mass had gradually increased and a 69% increase (P<0.01) was observed 4 months later. Triglyceride significantly decreased (23%, P < 0.01) and high density lipoprotein-cholesterol increased (10%, P < 0.01), whereas total cholesterol and LDL levels did not change 4 months later. The size of LDL increased significantly (P < 0.01). These results were consistent with the idea that preheparin LPL mass might be relating to the insulin sensitivity enhanced by troglitazone, as well as LDL particle size.
Diabetes Res Clin Pract 1999 Oct
PMID:The effect of insulin sensitizer, troglitazone, on lipoprotein lipase mass in preheparin serum. 1058 Jun 14


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