Intestinal endotoxin as a trigger of type 1 diabetes mellitus

The blood serum level of intestinal flora endotoxin was studied in 45 children and adolescents aged 3–17 years with type 1 diabetes mellitus. In all the patients the endotoxin levels 2.89 ± 0.33 EU/ml) were significantly elevated compared to the control group (0.4 ± 0.03 EU/ml). A higher level of endotoxin at the disease onset (3.93 ± 0.79 EU/ml) compared to that in children afflicted with diabetes for more than two years (2.37 ± 0.27 EU/ml) gives evidence of the involvement of endotoxin in the initiation of the disease.     

Serum IL-18 levels in patients with type 1 diabetes: relations to metabolic control and microvascular complications

The study was designed to examine serum IL-18 level and its relation to metabolic control parameters and microvascular complications in type 1 diabetes mellitus (DM). Sixty two patients with type 1 DM and 30 healthy individuals were enrolled in the study. Serum IL-18 levels of patients with type 1 DM were significantly increased compared to controls (293.4+/-133.4 vs 211.2+/-63.9 pg/ml, P=0.003). Patients with poor glycemic control had higher levels of IL-18 than patients with well glycemic control (329.9+/-141.0 vs 226.3+/-89.6 pg/ml, P=0.02). There was no significant difference between the serum IL-18 levels of patients with microvascular complications and those of patients without microvascular complications (307.6+/-127.6 vs 293.2+/-145.6 pg/ml, P>0.05). IL-18 correlated positively with HbA(1c) (r=0.32, P=0.01) and postprandial blood glucose (PPBG) (r=0.26, P=0.02); and negatively with HDL-cholesterol (HDL-C) (r=-0.38, P=0.007). By linear regression analysis, PPBG was determined as the most explanatory parameter for the alterations in serum IL-18 levels (P=0.02). High levels of IL-18 in patients with type 1 DM is related to short and long term glycemic control and HDL-C levels but not to microvascular complications.     

Lipopolysaccharide activates an innate immune system response in human adipose tissue in obesity and type 2 diabetes

Type 2 diabetes (T2DM) is associated with chronic low-grade inflammation. Adipose tissue (AT) may represent an important site of inflammation. 3T3-L1 studies have demonstrated that lipopolysaccharide (LPS) activates toll-like receptors (TLRs) to cause inflammation. For this study, we 1) examined activation of TLRs and adipocytokines by LPS in human abdominal subcutaneous (AbdSc) adipocytes, 2) examined blockade of NF-kappaB in human AbdSc adipocytes, 3) examined the innate immune pathway in AbdSc AT from lean, obese, and T2DM subjects, and 4) examined the association of circulating LPS in T2DM subjects. The findings showed that LPS increased TLR-2 protein expression twofold (P<0.05). Treatment of AbdSc adipocytes with LPS caused a significant increase in TNF-alpha and IL-6 secretion (IL-6, Control: 2.7+/-0.5 vs. LPS: 4.8+/-0.3 ng/ml; P<0.001; TNF-alpha, Control: 1.0+/-0.83 vs. LPS: 32.8+/-6.23 pg/ml; P<0.001). NF-kappaB inhibitor reduced IL-6 in AbdSc adipocytes (Control: 2.7+/-0.5 vs. NF-kappaB inhibitor: 2.1+/-0.4 ng/ml; P<0.001). AbdSc AT protein expression for TLR-2, MyD88, TRAF6, and NF-kappaB was increased in T2DM patients (P<0.05), and TLR-2, TRAF-6, and NF-kappaB were increased in LPS-treated adipocytes (P<0.05). Circulating LPS was 76% higher in T2DM subjects compared with matched controls. LPS correlated with insulin in controls (r=0.678, P<0.0001). Rosiglitazone (RSG) significantly reduced both fasting serum insulin levels (reduced by 51%, P=0.0395) and serum LPS (reduced by 35%, P=0.0139) in a subgroup of previously untreated T2DM patients. In summary, our results suggest that T2DM is associated with increased endotoxemia, with AT able to initiate an innate immune response. Thus, increased adiposity may increase proinflammatory cytokines and therefore contribute to the pathogenic risk of T2DM.     

The rat model of type 2 diabetic mellitus and its glycometabolism characters.

To develop a rat model of type 2 diabetic mellitus that simulated the common manifestation of the metabolic abnormalities and resembled the natural history of a certain type 2 diabetes in human population, male Sprague-Dawley rats (4 months old) were injected with low-dose (15 mg/kg) STZ after high fat diet (30% of calories as fat) for two months (L-STZ/2HF). The functional and histochemical changes in the pancreatic islets were examined. Insulin-glucose tolerance test, islet immunohistochemistry and other corresponding tests were performed and the data in L-STZ/2HF group were compared with that of other groups, such as the model of type 1 diabetes (given 50 mg/kg STZ) and the model of obesity (high fat diet). The body weight of rats in the group of rats given 15 mg/kg STZ after high fat diet for two months increased significantly more than that of rats in the group of rats given 50 mg/kg STZ (the model of type 1 diabetes) (595 +/- 33 g vs. 352 +/- 32 g, p<0.05). Fast blood glucose levels for L-STZ/2HF group were 16.92 +/- 1.68 mmol/l, versus 5.17 +/- 0.55 mmol/l in normal control and 5.59 +/- 0.61 mmol/l in rats given high fat diet only. Corresponding values for fast serum insulin were 0.66 +/- 0.15 ng/ml, 0.52 +/- 0.13 ng/ml, 0.29 +/- 0.11 ng/ml, respectively. Rats of type 2 diabetes (L-STZ/2HF) had elevated levels of triglyceride (TG, 3.82 +/- 0.88 mmol/l), and cholesterol(Ch, 2.38 +/- 0.55 mmol/l) compared with control (0.95 +/- 0.15 mmol/l and 1.31 +/- 0.3 mmol/l, respectively) (p<0.05). The islet morphology as examined by immunocytochemistry using insulin antibodies in the L-STZ/2HF group was affected and quantitative analysis showed the islet insulin content was higher than that of rats with type 1 diabetes (P<0.05). We concluded that the new rat model of type 2 diabetes established with conjunctive treatment of low dose of STZ and high fat diet was characterized by hyperglycemia and light impaired insulin secretion function accompanied by insulin resistance, which resembles the clinical manifestation of type 2 diabetes. Such a model, easily attainable and inexpensive, would help further elucidation of the underlying mechanisms of diabetes and its complications.     

Mild endotoxemia, NF-kappaB translocation, and cytokine increase during exertional heat stress in trained and untrained individuals

This study examined endotoxin-mediated cytokinemia during exertional heat stress (EHS). Subjects were divided into trained [TR; n=12, peak aerobic power (VO2peak)=70+/-2 ml.kg lean body mass(-1).min(-1)] and untrained (UT; n=11, VO2peak=50+/-1 ml.kg lean body mass(-1).min(-1)) groups before walking at 4.5 km/h with 2% elevation in a climatic chamber (40 degrees C, 30% relative humidity) wearing protective clothing until exhaustion (Exh). Venous blood samples at baseline and 0.5 degrees C rectal temperature increments (38.0, 38.5, 39.0, 39.5, and 40.0 degrees C/Exh) were analyzed for endotoxin, lipopolysaccharide binding protein, circulating cytokines, and intranuclear NF-kappaB translocation. Baseline and Exh samples were also stimulated with LPS (100 ng/ml) and cultured in vitro in a 37 degrees C water bath for 30 min. Phenotypic determination of natural killer cell frequency was also determined. Enhanced blood (104+/-6 vs. 84+/-3 ml/kg) and plasma volumes (64+/-4 vs. 51+/-2 ml/kg) were observed in TR compared with UT subjects. EHS produced an increased concentration of circulating endotoxin in both TR (8+/-2 pg/ml) and UT subjects (15+/-3 pg/ml) (range: not detected to 32 pg/ml), corresponding with NF-kappaB translocation and cytokine increases in both groups. In addition, circulating levels of tumor necrosis factor-alpha and IL-6 were also elevated combined with concomitant increases in IL-1 receptor antagonist in both groups and IL-10 in TR subjects only. Findings suggest that the threshold for endotoxin leakage and inflammatory activation during EHS occurs at a lower temperature in UT compared with TR subjects and support the endotoxin translocation hypothesis of exertional heat stroke, linking endotoxin tolerance and heat tolerance.     

Endotoxin stimulates endothelin-release in vivo and in vitro as determined by radioimmunoassay

A marked increase in immunoreactive endothelin was observed in rat serum collected within 10-15 min after infusion of endotoxin. Endothelin level was 117 +/- 11.5 pg/ml (mean +/- S.E., N = 4) in rats exposed to endotoxin as compared with undetectable levels (less than 2 pg/ml, N = 4) in controls. We have also observed a significant stimulation of endothelin-release by endotoxin from cultured bovine transformed thoractic aortic endothelial cells at concentrations of endotoxin ranging between 0.1 and 10.0 micrograms/ml. Serum was indispensable for the stimulating effect of endotoxin, although serum itself did not show any effect at the concentration used (1%). These results suggest that endothelin plays an important role in mediation of pathophysiological responses caused by endotoxin. The levels of endothelin were measured by radioimmunoassay with high sensitivity.     

Identification of variables influencing resistin serum levels in patients with type 1 and type 2 diabetes mellitus.

BACKGROUND: Resistin, a peptide hormone, has been discussed controversially as a missing link between obesity and insulin resistance. In contrast to resistin mRNA expression in adipose tissue, data on human serum levels in obesity and diabetes mellitus is scarce. The physiological range of serum resistin levels, reference values or adjusted percentiles have not yet been determined, making the interpretation of serum resistin concentrations quite difficult. METHODS: Resistin serum concentrations were measured systematically by ELISA in 216 healthy controls, 555 patients with type 2 diabetes and 114 patients with type 1 diabetes. Mean values, median, and range were determined, and BMI-, gender-, and disease-adapted percentiles were calculated for all subgroups. RESULTS: Age and gender did not have any influence on resistin levels. BMI and resistin levels were positively correlated in healthy controls (p = 0.02), albeit with a weak correlation coefficient. This correlation was absent in patients with type 1 and type 2 diabetes. In both genders, healthy controls had significantly higher resistin levels than patients with type 1 and type 2 diabetes (7.9 +/- 0.2 ng/ml vs. 5.7 +/- 0.2 ng/ml and 5.5 +/- 0.1 ng/ml, respectively; p < 0.0001). There was no correlation between resistin levels and occurrence of diabetic retinopathy or nephropathy. CONCLUSIONS: Serum resistin levels can be measured by ELISA over a broad range from 0.6 ng/ml up to 27.7 ng/ml, suggesting that percentiles might be helpful in the interpretation of an individuals resistin value. While age and gender do not influence resistin levels, BMI and occurrence of diabetes have to be considered.     

Nitric oxide dependent and independent effects of in vitro incubation or endotoxin on vascular reactivity in rat aorta.

We sought to delineate contributions of nitric oxide (NO) and other mechanisms to impairment of contraction and endothelium-dependent relaxation following prolonged in vitro incubation, endotoxin and interleukin-1 exposure in isolated rat aorta. Responses from freshly-dissected (control) rings +/-endothelium were compared with those from rings incubated in sterile, antibiotic containing medium +/- E. Coli endotoxin (LPS, 100 microg/ml) +/- interleukin-1 (IL-1, 40 ng/ml) at 37 degrees C for 20-24 h. In some experiments, medium included dexamethasone (DEX, 1 microg/ml), cycloheximide (10 microg/ml), or N(G)-nitro-L-arginine (NNLA, 10(-4)M). After incubation, medium nitrite was measured. Incubation alone, without addition of inflammatory mediators, impaired contraction in an agonist-specific manner, by both NO-dependent and NO-independent mechanisms. Either LPS or IL-1 diminished contraction further, in a similarly heterogeneous manner. For example, contractions were changed in LPS-incubated endothelium-intact rings (vs. fresh controls) by -85%, +115%, -15%, -96%, and -37% for phenylephrine (PE), serotonin, prostaglandin F2alpha, angiotensin II, and U46619, respectively. NO synthase inhibition with NNLA either following, or during LPS incubation only partially normalized subsequent PE contractions, an effect which was smaller than that of DEX. Nitrite accumulation was inversely proportional to PE response, even though NO was not the sole mediator of LPS-impaired contraction. LPS and IL-1 nearly abolished ACh-induced relaxation, which was only mildly impaired by incubation alone. We conclude that prolonged incubation impaired vasoconstriction via both NO synthase induction and NO-independent mechanisms. LPS or IL-1 incubation impaired vasoconstriction further, primarily by NO-independent mechanisms. Moreover, vasoconstrictor responses following LPS varied with the agonist's ability to modulate endothelial NO release. These results are in accord with the failure of NO synthase inhibition to fully restore systemic vascular resistance indices in experimental endotoxemia or in hyperdynamic septic patients.     

Direct stimulation of monocyte release of interleukin 1 by mycobacterial protein antigens

We examined stimulation of monocyte (MN) release of interleukin 1 (IL 1) by soluble microbial products. MN from tuberculin skin test nonreactive donors incubated with PPD (100 micrograms/ml) released IL 1 activity of 80.5 +/- 33.9 U/ml (mean +/- SD, n = 6), similar to that induced by optimal concentrations of LPS (76.4 U/ml). OKT3-reactive cells were not required for this process. PPD-stimulated IL 1 release by MN did not appear to be due to endotoxin contamination, as 1) PPD contained 0.01% endotoxin, 2) MN incubated in LPS (0.1 micrograms/ml) produced 19.5 +/- 13.9 U/ml, significantly less than PPD (p = 0.03), and 3) addition of polymyxin B (12.5 micrograms/ml) abrogated IL 1 production in response to LPS (0.1 microgram/ml) but had no significant effect on PPD induction of IL 1. Antigen 5, a partially purified cytoplasmic antigen of Mycobacterium tuberculosis, had similar IL 1-inducing effects. Arabinogalactan (a mycobacterial polysaccharide), streptolysin O, and tetanus toxoid did not. Thus, mycobacterial protein antigens directly stimulate MN to release IL 1. This property may be central to the response of the naive host to mycobacterial infection and may play a pathophysiologic role in tuberculosis.     

Plasma soluble intercellular adhesion molecule 1 levels are increased in type 2 diabetic patients with nephropathy

BACKGROUND/AIM: Intercellular adhesion molecule 1 (ICAM-1) is a mediator in the recruitment of leukocytes in the glomerular cells. The role of ICAM-1 in diabetic complications is still a matter of debate. This study was performed to investigate the relation of plasma soluble ICAM-1 (sICAM-1) to nephropathy in patients with type 2 diabetes mellitus. METHODS: Ninety-three patients (24 males and 69 females) with type 2 diabetes mellitus were included into the study. Fifty patients had nephropathy, and 43 were free from nephropathy. Fifty healthy subjects (14 males and 36 females) served as the control group (group 1). Twenty-five of the diabetic patients had microalbuminuria (group 2), 25 had macroalbuminuria (group 3), and 43 had neither micro- nor macroalbuminuria (group 4). The plasma sICAM-1 levels were measured in blood samples drawn after fasting. RESULTS: The mean plasma sICAM-1 levels were not different in the 93 diabetic patients as compared with the healthy controls (392.7 +/- 119.5 vs. 350.1 +/- 90.2 ng/ml, p > 0.05). The mean sICAM-1 level was significantly higher in the diabetic patients with nephropathy than in those without nephropathy (430.3 +/- 78.2 vs. 368.2 +/- 122.5 ng/ml, p = 0.03) and in the controls (430.3 +/- 78.2 vs. 350.1 +/- 90.2 ng/ml, p = 0.016). The difference in sICAM-1 levels between groups 2 and 3 was not significant (p > 0.05). The plasma sICAM-1 levels were significantly higher in both groups 2 and 3 than in both groups 1 and 4 (434.5 +/- 129.2 vs. 427.2 +/- 113.7 ng/ml and 368.2 +/- 122.5 vs. 350.1 +/- 90.2 ng/ml, respectively). CONCLUSIONS: The plasma sICAM-1 levels in patients with type 2 diabetes mellitus are not significantly different from those in nondiabetic subjects. High levels of sICAM-1 suggest that sICAM-1 may play a role in the development of nephropathy in patients with type 2 diabetes mellitus.     

Increased monocyte MCP-1 production in acute alcoholic hepatitis.

Monocyte chemoattractant protein-1 (MCP-1) is a potent mononuclear cell-specific chemotactic protein. MCP-1 is a candidate chemoattractant for activation and hepatic infiltration of mononuclear cells in alcoholic hepatitis (AH). Blood was collected from 15 patients with AH (mean bilirubin 17.6+/-3.5 mg/dl; normal 0. 2-1.0 mg/dl) on admission and at time points for up to 6 months. Peripheral blood monocytes were isolated and MCP-1 production assessed by measuring MCP-1 concentrations in monocyte culture supernatants after overnight (20 h) incubation. Monocytes from normal subjects did not product detectable MCP-1 unless stimulated with endotoxin (LPS;5 microg/ml). The mean level of constitutive MCP-1 from AH patient monocytes was 4694+/-2432 pg/ml 20 h on admission. The mean MCP-1 level for LPS-treated monocytes was 4903+/-1540 pg/ml 20 h for normal subjects and was significantly elevated in AH patients to 11589+/-3266 pg/ml/20 h. AH patient monocyte MCP-1 production was decreased in vitro when monocytes were treated with N-acetylcysteine (5 mM) and also decreased over the 6-month study as the patients improved clinically. MCP-1 plasma levels were below the detection limits of the assay used in both AH patients and normal subjects. Thus, monocytes from AH patients not only constitutively product MCP-1, but also produce higher levels of MCP-1 with endotoxin stimulation. Further studies are needed to clarify the role of MCP-1 in the activation and hepatic infiltration of mononuclear cells in alcoholic liver disease.     

Endotoxin inactivating activity of rat serum

The ability of rat serum to inactivate endotoxin (LPS) was assessed with the aid of the limulus amebocyte lysate assay. Following the addition of various amounts of endotoxin to normal serum the mixture was incubated for 1 hr at 37 degrees C and the residual endotoxin activity determined. One milliliter of rat serum inactivated between 5 and 10 micrograms Escherichia coli LPS per hour. Heating serum for 45 min at 56 degrees C resulted in loss of 80-90% of the LPS inhibitor (LPSI) activity. Serum from cobra venom factor (CVF)-treated rats inactivated between 0.5 and 2.5 micrograms LPS/ml serum. Serum from tolerant rats, even after heating for 45 min at 56 degrees C, inactivates between 10 and 15 micrograms LPS/ml serum/hr; decomplemented tolerant rat serum neutralizes between 5 and 10 micrograms LPS/ml serum/hr. Clearly, the tolerant rat has large quantities of LPSI activity, which does not appear to be complement. The inhibitor found in tolerant rat serum is not species specific since it inactivates Salmonella minnesota and Salmonella typhimurium endotoxins to the same degree and in the same amount as E. coli endotoxin, the agent used to induce tolerance. Both heating serum (56 degrees C) and lead acetate reduce LPSI activity.     

Management of severely brittle diabetes by continuous subcutaneous and intramuscular insulin infusions: evidence for a defect in subcutaneous insulin absorption.

Severely brittle diabetes is defined as a rare subtype of insulin-dependent diabetes with wide, fast, unpredictable, and inexplicable swings in blood glucose concentration, often culminating in ketoacidosis or hypoglycaemic coma. To assess the role of inappropriate type, amount, or timing of insulin treatment and the route of administration as a cause of severe brittleness six patients with continuous subcutaneous insulin infusion, which provides a high degree of optimisation of dosage with exogenous insulin in stable diabetics. The glycaemic control achieved during continuous subcutaneous insulin infusion was compared with that during continuous intramuscular insulin infusion. Six patients with non-brittle diabetes were also treated by continuous subcutaneous insulin infusion. These patients achieved the expected improvement in glycaemic control (mean +/- SD plasma glucose concentration 5.1 +/- 2.3 mmol/l (92 +/- 41 mg/100 ml)), but not the patients with brittle diabetes remained uncontrolled with continuous subcutaneous infusion (13.6 +/- 5.8 mmol/1 (245 +/- 105 mg/100 ml) compared with 10.3 +/- 4.1 mmol/l (186 +/- 74 mg/100 ml) during treatment with optimised conventional subcutaneous injections). During continuous intramuscular infusion, however, glycaemic control in five of the patients with brittle diabetes was significantly improved (7.7 +/- 2.6 mmol/l (139 +/- 47 mg/100 ml). The remaining patient with brittle diabetes, previously safely controlled only with continuous intravenous insulin, did not respond to continuous intramuscular infusion. It is concluded that in five of the six patients with brittle diabetes studied here impaired or irregular absorption of insulin from the subcutaneous site played a more important part in their hyperlability than inappropriate injection strategies. This absorption defect was presumably bypassed by the intramuscular route.     

Anti-tumor necrosis factor antibody therapy fails to prevent lethality after cecal ligation and puncture or endotoxemia.

Cytokines have been studied intensively to delineate their role in the altered pathophysiology observed in septic shock. We studied the role of TNF in the lethality of two well characterized models of septic shock by inhibiting TNF's activity with a specific antibody. In the first model, sepsis was induced by cecal ligation and puncture (CLP), and in the second model sepsis was induced by either an i.p. or i.v. injection of LPS. After CLP, plasma endotoxin was detectable within 4 h and reached a peak at 8 h (136 +/- 109 ng/ml). TNF bioactivity peaked at 12 h (528 +/- 267 pg/ml) at a significantly higher level than sham-operated control mice (64 +/- 31 pg/ml). After i.p. LPS, TNF peaked much more quickly (90 min) compared with CLP and at a significantly higher level (107,900 +/- 25,000 pg/ml). Another cytokine studied in septic shock, IL-6, peaked at 12 h after CLP at 1011 +/- 431 pg/ml, and at 90 min after lethal LPS at 16,300 +/- 3,700 pg/ml. Mice were treated with an anti-TNF antibody that has been shown previously to inhibit in vivo TNF activity. Antibody treatment of mice subjected to CLP significantly reduced TNF bioactivity but did not reduce mortality or pulmonary neutrophilic infiltration. In the i.v. LPS model, anti-TNF antibody treatment concomitant with LPS injection reduced plasma TNF activity from 80,000 +/- 20,000 pg/ml to undetectable levels. However, anti-TNF treatment immediately before either i.v. or i.p. LPS did not reduce mortality. Additionally, when the antibody was administered 4 h before the lethal i.v. LPS, there was no reduction in lethality. These data show that in two separate models of septic shock blockade of TNF biologic activity will not prevent lethality.     

Evidence for IFN-gamma as a mediator of the lethality of endotoxin and tumor necrosis factor-alpha.

Current evidence indicates that endogenously produced peptide cytokines, most notably TNF-alpha and IL-1, mediate the lethality of experimental endotoxemia. Because circulating serum levels of IFN-gamma can be detected soon after TNF-alpha and IL-1 in response to endotoxin, we investigated the role of IFN-gamma in endotoxin and TNF-alpha lethality. Specific neutralizing antibodies to murine TNF-alpha (anti-TNF-alpha Ab) or murine IFN gamma (anti-IFN-gamma Ab) produced in our laboratory protected mice against the lethality of Escherichia coli endotoxin (LPS) administered 6 h later. Serum IFN-gamma levels 2 h after i.v. LPS were lower in mice treated with anti-TNF-alpha Ab compared to mice that received nonimmune IgG (median less than 2.5 vs 3.0 U/ml, P2 less than 0.05). In contrast, serum TNF-alpha levels 1 h after i.v. LPS peaked more than fourfold higher in mice treated with anti-IFN-gamma Ab compared to controls (median greater than 6400 vs 1405 pg/ml, p2 less than 0.05). Doses of TNF-alpha (300 micrograms/kg) and IFN-gamma (50,000 U) which were well tolerated when given individually were synergistically lethal in combination (0% lethality vs 100% lethality, P2 less than 0.001), and were associated with higher serum levels of IL-6 than with either cytokine alone. Anti-IFN-gamma Ab provided complete protection against exogenous human rTNF-alpha at the LD100 dose (1400 micrograms/kg, p2 less than 0.001), and in fact prevented lethality at doses four- to fivefold greater than the LD100 human rTNF-alpha (up to 6000 micrograms/kg). We conclude that IFN-gamma is synergistic with TNF-alpha, is essential for the lethality of LPS and TNF-alpha, and may have modulating effects on the negative control of serum levels of TNF-alpha after LPS in mice.     

Serum but not myocardial TNF-alpha concentration is increased in pacing-induced heart failure in rabbits

In animals and patients with severe heart failure (HF), the serum tumor necrosis factor-alpha (TNF-alpha) concentration is increased. It is, however, still controversial whether or not such increased serum TNF-alpha originates from the heart itself or is of peripheral origin secondary to gastrointestinal congestion and increased endotoxin concentration. We therefore now examined TNF-alpha in serum, myocardium, and liver of sham-operated and HF rabbits. In nine rabbits in which HF was induced by left ventricular (LV) pacing at 400 beats/min for 3 wk, LV end-diastolic diameter was increased and systolic shortening fraction (9.4 +/- 1.0 vs. 28.5 +/- 1.3%, echocardiography, P < 0.05) was reduced. Serum TNF-alpha was higher in HF than in sham-operated rabbits (240 +/- 24 vs. 150 +/- 22 U/ml, WEHI-cell assay, P < 0.05). In the heart, TNF-alpha was located mainly in the vascular endothelium (immunohistochemistry), and TNF-alpha protein (920 +/- 160 vs. 900 +/- 95 U/g) did not differ between groups. In the liver of HF rabbits, hepatocytes expressed TNF-alpha, and TNF-alpha protein was increased compared with sham-operated rabbits (2,390 +/- 310 vs. 1,220 +/- 135 U/g, P < 0.05) and correlated to the number of hepatic leukocytes (r = 0.85) and serum TNF-alpha (r = 0.69). The intestinal endotoxin concentration was 24.5 +/- 1.2 vs. 17.0 +/- 3.1 endotoxin units/g wet wt (P < 0.05) in HF compared with sham-operated rabbits. In this HF model, serum but not myocardial TNF-alpha is increased. The increased serum TNF-alpha originates from peripheral sources.     

Pancreatic B-cell function in non-insulin-dependent diabetes mellitus during successive periods of sulfonylurea and insulin treatment: serum C-peptide response to glucagon and urine C-peptide excretion

Serum C-peptide responses to glucagon and daily urine C-peptide excretion in successive periods of different treatment in two groups of patients with non-insulin-dependent diabetes mellitus (NIDDM) (mean interval between two tests less than 1 month) were compared. In group A patients (n = 8), the glycemic control was improved after transferring the treatment from sulfonylurea (SU) to insulin (fasting plasma glucose: SU: 192 +/- 47, insulin: 127 +/- 21 mg/dl, mean +/- S.D., p less than 0.01). Fasting serum C-peptide immunoreactivity (CPR) was significantly lower at the period of insulin treatment (SU: 1.93 +/- 1.01, insulin: 1.47 +/- 0.79 ng/ml, p less than 0.05), but there was no difference in the increase in serum CPR (maximal--fasting) (delta serum CPR) during glucagon stimulation in the two periods of treatment (SU: 1.70 +/- 0.72, insulin: 1.47 +/- 0.98 ng/ml). In group B patients (n = 7), there was no significant difference in glycemic control after transferring the treatment from insulin to SU (fasting plasma glucose: insulin: 127 +/- 24, SU: 103 +/- 13 mg/dl). Fasting serum CPR was significantly lower during the period of insulin treatment (insulin: 1.39 +/- 0.64, SU: 2.21 +/- 0.86 ng/ml, p less than 0.025), but delta serum CPR during glucagon stimulation still showed no significant difference between the two periods (insulin: 1.97 +/- 1.16, SU: 2.33 +/- 1.57 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)     

Simultaneous measurement of multiple Th1 and Th2 serum cytokines in psoriasis and correlation with disease severity

BACKGROUND: Psoriatic plaques have been shown to contain increased levels of proinflammatory cytokines. Serum levels of interleukin (IL)-6, IL-7, IL-8, and interferon (IFN)-gamma have been reported elevated in psoriatic patients. AIM: To evaluate serum cytokine profiles in psoriasis patients by improved enzyme-linked immunosorbent assay (ELISA) technique and to correlate these levels with disease severity. METHODS: We analyzed single serum samples from 10 patients with active untreated psoriasis, two patients with active treated psoriasis, and five healthy volunteers for major T helper type 1 and T helper type 2 cytokines using the LINCOplex ELISA multi-analyte detection system that permits simultaneous detection of multiple cytokines from a single sample. The disease severity, including erythema, induration, scale, and surface area, was assessed. RESULTS: IFN-gamma was markedly elevated in all sera from psoriasis patients, 33.8 +/- 1.3 pg/ml (mean +/- standard error) versus 8 +/- 1.5 pg/ml for normal controls (p < 0.01), and positively correlated with all indices of disease severity (Spearman r > 0.6). IL-8 was also increased in psoriasis patients (24.4 +/- 1.8 pg/ml) versus normal controls (3.6 +/- 1.2 pg/ml) (p < 0.05) and positively correlated with the degree of erythema (Spearman r > 0.6). Mean IL-12 levels were decreased in sera from psoriasis patients (8.5 +/- 1.2 pg/ml) compared with normal controls (42.2 +/- 5.3 pg/ml) (p < 0.01). Also, serum IL-10 levels were below detection levels in psoriatics compared with controls (6.4 +/- 1.3 pg/ml). CONCLUSIONS: This new ELISA system allowed rapid and reliable detection of numerous cytokines in single serum samples from patients with psoriasis. We observed that IFN-gamma and IL-8 cytokines were elevated in psoriatics and correlated with parameters of disease severity while IL-10 and IL-12 were decreased.     

High levels of Mn-superoxide dismutase in serum of patients with neuroblastoma and in human neuroblastoma cell lines.

Levels of serum manganese superoxide dismutase (Mn-SOD) in normal children aged from 1 to 14 years and children with various hematological and malignant diseases were determined by enzyme-linked immunosorbent assay (ELISA). In the normal children, the serum Mn-SOD levels gradually increased in proportion to age. By 8 years of age, the Mn-SOD level was nearly at the adult level. The normal values of serum Mn-SOD (mean +/- SD) of children below 4 and above 8 years old were 48 +/- 10.2 ng/ml and 84 +/- 22.5 ng/ml, respectively. Assuming the upper limit of normal Mn-SOD level in serum to be the mean value +/- 2 SD of children at each age, high serum levels of Mn-SOD were found for 8 of 12 patients with neuroblastoma, three of four patients with Wilms tumor, and four of five patients with acute myeloid leukemia. The patients with neuroblastoma exhibited a transient increase in Mn-SOD following chemotherapy, but after 1 week the levels decreased markedly to the control levels. The changes in serum Mn-SOD levels in the patients with neuroblastoma correlated well with the levels of neuron-specific enolase. Mn-SOD was intensely stained in bone marrow cells of patients whose cancer cells had moved into the bone marrow. High levels of Mn-SOD were also found in cultured human neuroblastoma cells. These data indicate that Mn-SOD is expressed in neuroblastoma cells, may serve as one of the diagnostic and prognostic markers for the neuroblastoma, and may be useful to predict the effectiveness of chemotherapy for neuroblastoma and the recurrence of this disease.     

The effect of pramlintide (amylin analogue) treatment on bone metabolism and bone density in patients with type 1 diabetes mellitus.

Amylin is a 37-amino-acid peptide related to CGRP and calcitonin. It is co-secreted with insulin from pancreatic beta-cells. Amylin is deficient with type 1 diabetes mellitus. To study the in vivo effects of amylin in humans, diabetic patients are an adequate model of chronic amylin deficiency. We investigated the effect of a 12 months pramlintide therapy (amylin analogue) on bone metabolism in patients with type 1 diabetes mellitus. 23 patients with type 1 diabetes mellitus (age 45.2 +/- 10.3 years, duration of diabetes mellitus 20.7 +/- 9.8 years, 13 male, 10 female) injected themselves 0.1 ml pramlintide, a human amylin analogue, four times per day for a period of 12 months. Bone mineral density measurements of the lumbar spine by dual-energy X-ray absorptiometry (DXA), and biochemical markers of bone metabolism (serum-calcium, PTH, osteocalcin, urinary pyridinium cross-links) were obtained before and one year after starting pramlintide therapy. None of the following parameters changed significantly: bone density, serum calcium, PTH, osteocalcin or pyridinium cross-links. Only osteocalcin decreased from 7.205 ng/ml to 5.825 ng/ml, but this change was not statistically significant. We conclude that a one-year pramlintide therapy does not affect bone density or bone metabolism in patients with type 1 diabetes mellitus without osteopenia (based on the markers used).