Interactive influences of peroxisome proliferator-activated receptor α activation and glucocorticoids on pancreatic beta cell compensation in insulin resistance induced by dietary saturated fat in the rat

Aims/hypothesis We sought to elucidate whether excess glucocorticoids and increased dietary lipids act synergistically to impair glucose tolerance and, if so, whether activation of peroxisome proliferator-activated receptor (PPAR) has an adverse or beneficial effect on glucose tolerance.Methods Dexamethasone (100 g kg^–1 body weight day^–1; 5 days) was administered to insulin-resistant rats fed a high-saturated-fat (HF) diet for 4weeks. The PPAR agonist WY14643 was administered (50 mg kg^–1 body weight intraperitoneally) 24 h before sampling. Glucose-stimulated insulin secretion (GSIS) was assessed in vivo after an acute glucose bolus injection, and in vitro using step-up and step-down islet perifusions.Results Although neither PPAR activation nor dexamethasone alone affected fasting glycaemia in the HF group, dexamethasone in combination with PPAR activation elicited marked postabsorptive hyperglycaemia. Dexamethasone treatment of HF rats had little effect on GSIS after an acute glucose challenge in vivo, but induced glucose intolerance. PPAR activation augmented GSIS in dexamethasone-treated HF rats in vivo, restoring glucose tolerance. Contrasting with data obtained in vivo, greatly enhanced peak rates of GSIS were observed ex vivo in perifusions of islets from dexamethasone-treated HF rats compared with those from untreated HF rats, an effect attenuated by antecedent PPAR activation.Conclusions/interpretation The study demonstrates that glucocorticoid excess precipitates the development of glucose intolerance in rats maintained on a high-saturated-fat diet. It does this by interrupting the negative feedback loop between insulin sensitivity and secretion in vivo, such that further enhancement of compensatory insulin secretion is not possible. PPAR activation restores the coupling between insulin secretion and action.     

Systemic lupus erythematosus arising during interferon-alpha therapy for cryoglobulinemic vasculitis associated with hepatitis C

We present the case of a 53-year-old woman who developed systemic lupus erythematosus (SLE) after being treated with interferon-alpha (IFN-) for cryoglobulinemic vasculitis associated with hepatitis C virus (HCV) infection. Her cryoglobulinemic vasculitis resolved rapidly with IFN- treatment. However, after 10 months of IFN- therapy, she developed a photosensitive malar rash, oral ulcers, arthralgias, lymphopenia, and anti-SSA autoantibodies. She was diagnosed with SLE induced by IFN- therapy. IFN- was discontinued, she was treated with a short course of prednisone and hydroxychloroquine, and she improved rapidly. This is the first report of IFN--induced SLE complicating treatment of cryoglobulinemic vasculitis associated with HCV infection. The development of SLE during therapy with IFN- could be due to direct immunomodulation by IFN-, and review of experimental data and prior case reports suggests a pathogenic role for IFN- in SLE.No financial support or conflict of interest to declare     

Mechanisms and Roles of Neutrophil Infiltration in Stress-Induced Gastric Injury in Rats

Water-immersion and restraint stress is associated with an increase in neutrophil infiltration into the gastric mucosa, but the mechanism responsible for this infiltration is unclear. We investigated the involvement of intercellular adhesion molecule-1 (ICAM-1) and tumor necrosis factor- (TNF-) in neutrophil infiltration in stress-induced gastric injury in rats. Rats were administered neutralizing antibody against ICAM-1 or TNF- and were subjected to induction of gastric injury by 6-hr water-immersion and restraint stress. To evaluate the relationship between gastric acid and neutrophil infiltration, some rats were given cimetidine before administration of stress. Neutralizing antibodies inhibited both the lesion formation and the increase in myeloperoxidase activity induced by stress. Expression of ICAM-1 on endothelial cells was increased by stress, accompanied by an increase of TNF--positive cells. Antibody against TNF- inhibited this increase in ICAM-1 expression. Cimetidine almost completely inhibited gastric lesions, but did not affect myeloperoxidase activity. In conclusion, neutrophil infiltration in stress-induced gastric injury may be mediated by ICAM-1 and TNF-, but not gastric acid, and may play crucial roles in the progression of gastric injury.     

Rapid detection of −α 4.2 deletion of α-thalassemia-2 by polymerase chain reaction

Summary We sequenced part of the X boxes of-thalassemia-1 of Southeast Asia type (- -SEA) with– ^4.2,– ^3.7,– ^G-Taichung, and ^CS. We found the X box of– ^3.7 belonged to the X box of 2 globin gene and the X box of ^cs contained X boxes of both al and2 globin gene, whereas the X box of– ^4.2 and– ^G-Taichung was a hybrid of X boxes of 2 and 1 globin gene. We also found there are two types of– ^4.2 deletion; type 1 is a common type of– ^4.2 deletion and type 2 is linkage to– ^G-Taichung. We used a combination of two methods, the amplification refractory mutation system (ARMS) and the amplified created restriction sites (ACRS), to amplify the hybrids of X boxes specifically. The upstream primer for X box of2 globin gene was designed following the standard ARMS procedure to amplify the X segment of the-globin gene. The downstream primer was designed according to the ACRS method to check the specificity of PCR products. Using this approach, we can diagnose the different types of– ^4.2 deletion. This kind of approach can also be used to amplify the specific region from the cluster of highly homologous genes.     

Release of TNFα and IL6 from human monocytes infected withMycobacterium kansasii: A comparison toMycobacterium avium

Summary Tumor necrosis factor (TNF) and interleukin 6 (IL6) are cytokines with a varied spectrum of inflammatory and immunological activities, for example modulation of acute phase proteins, fever and stimulation of B-lymphocytes.Mycobacterium avium has been shown to stimulate the release of TNF and IL6 from cultured human monocytes and macrophages into the cell supernatant. Cultured human monocytes were infected withMycobacterium kansasii andM. avium. The concentrations of TNF and IL6 were measured in the supernatant. Monocytes infected withM. kansasii produced significantly lower amounts of TNF (34.8±20.3 pg/ml) and IL6 (12.0±8.9 pg/ml) compared to monocytes infected withM. avium (198.3±171.7 pg/ml and 63.2±37.6 pg/ml respectively). The extent of cytokine production might be relevant for the clinical manifestation of mycobacterial disease.

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Freisetzung von TNF und IL6 aus mitMyobacterium kansasii infizierten humanen Monozytenkulturen; ein Vergleich mitMycobacterium avium

Zusammenfassung Tumor-Nekrose-Faktor (TNF) und Interleukin 6 (IL6) sind Zytokine mit einem breiten Spektrum an inflammatorischen und immunologischen Aktivitäten wie beispielsweise Modulation der Akutphase-Proteine, Fieber und Stimulation der B-Lymphozyten. Es konnte gezeigt werden, daßMycobacterium avium den Ausstoß von TNF und IL6 aus humanen Monozyten/Makrophagenkulturen in den Zellüberstand stimuliert. Humane Monozytenkulturen wurden mitMycobacterium kansasii undM. avium infiziert. In den Zellüberständen wurden die Konzentrationen an TNF und IL6 gemessen. Die mitM. kansasii infizierten Monozytenkulturen produzierten signifikant weniger TNF (34,8±20,3 pg/ml) und IL6 (12,0±8,9 pg/ml) verglichen mit jenen infiziert mitM. avium (198,3±171,7 pg/ml beziehungsweise 63,2±37,6 pg/ml). Das Ausmaß der Zytokinproduktion könnte für das klinische Bild mykobakterieller Infektionen von Bedeutung sein.

     

Tumour necrosis factor-α and the failing heart

Abstract. Immune activation plays a signicant role in the development and progression of chronic heart failure (CHF). Indeed, pro-inammatory cytokines, especially tumour necrosis factor- (TNF) are activated in this condition and exert direct detrimental actions on the myocardium. Physiological dampeners of TNF production, such as interleukin-10, catecholamines, cortisol, and others fail in the course of the disease. However, the outcomes of two large-scale clinical trials with etanercept and iniximab, which directly antagonise TNF have been rather disappointing. Nevertheless, TNF antagonism remains a major target of CHF therapy, although counterbalancing this cytokine alone may not be sufcient.     

Expression and secretion of alpha1-proteinase inhibitor are regulated by proinflammatory cytokines in human pancreatic islet cells

Aims/hypothesis Alpha1-proteinase inhibitor (1-PI) has been considered a key player in inflammatory processes. In humans, the main production site of 1-PI is the liver, but other tissues, including pancreatic islets, also synthesise this molecule. The aims of this study were to assess the islet cell types that produce 1-PI, to determine whether 1-PI is actually secreted by islet cells, and to assess how its production and/or secretion are regulated.Methods Expression of 1-PI in human islet cells was assessed by immunofluorescence, electron microscopy and western blotting. Release of 1-PI was analysed by reverse haemolytic plaque assay and ELISA. The effects of cytokines on 1-PI synthesis and secretion were tested.Results Immunofluorescence showed that alpha and delta cells do express 1-PI, whereas beta cells do not. By electron microscopy, we demonstrated a colocalisation of 1-PI with glucagon and somatostatin within secretory granules. Immunolabelling also revealed localisation of 1-PI within the Golgi apparatus, related vesicles and lysosomal structures. The expression of 1-PI in islet cells was also demonstrated by western blotting and ELISA of protein extracts. ELISA and reverse haemolytic plaque assay showed that 1-PI is secreted into the culture medium. Treatment of islet cells with IL-1 and oncostatin M for 4 days increased the production and release of 1-PI.Conclusions/interpretation Our results demonstrate that 1-PI is expressed by the alpha and delta cells of human islets, and that proinflammatory cytokines enhance the production and release of this inhibitor.     

Multiple steroid hormone receptors in normal and abnormal human endometrium

Summary The cytoplasmic concentrations of ER, AR, PR, and GR were determined in 124 specimens of normal and abnormal endometrium and other uterine human tissues by the DCC technique. In the endometrial carcinoma group, we observed that pretreatment with MAP leads to low cellularity, higher amount of AR, lower amounts of detectable ER, GR, and PR: the last receptor was almost always absent. A positive correlation between ER presence and tumor grade of differentiation was found in endometrial tumors from hormoneuntreated patients. With the value of 142 fmol/mg DNA as the cut off point between high and low binding capacity, the frequency of the single receptors within the hormone-untreated cancer group ranged from 61% to 88%; ER and PR were simultaneously present in 55% of cases (they are tightly correlated in the different biopsies with respect to frequency and amount); ER-AR-PR were present in 45% and all the four receptors in 40% of cases. Slightly higher values were found in normal endometrium collected from hormone-untreated patients.Abbreviations ER 17-estradiol receptor - AR 5-dihydrotestosterone receptor - PR progesterone receptor - GR glucocorticoid receptors - -DHT 5-dihydrotestosterone - -DHT 5-dihydrotestosterone - MAP medroxyprogesterone acetate - P progesterone - F cortisol - T testosterone - E 17-estradiol - DES diethylstilbestrol - TEBG testosterone-estradiol binding globulin - CBG corticosteroid binding globulin - DCC dextran-coated charcoal - R 1881 methyltrienolone - Kd dissociation constant This work was supported by a grant from Ministero della Pubblica Istruzione, Rome and Donazione Testoni, Bologna, Italy     

Tris discriminates between the different α-glucosidase activities from extracts of human neutrophils

Summary In an attempt to detect acid maltase deficiency in neutrophils from patients with type II glycogenosis, without interference from the renal -glucosidase activity present in these cells, we have evaluated the contribution of the renal component in the total activity measured at pH 4.0 in extracts of human neutrophils. The renal contribution is about 13–25% and renal glucosidase appears to be closely related to the enzyme present on the epithelium of small intestine, which is known to be inhibited by Tris. We have used this compound as a selective inhibitor of the renal component of -glucosidase activity measured at pH 4.0 in total extracts of neutrophils. Our results demonstrate that 0.1 mol/L Tris is an inhibitor of the renal -glucosidase present in neutrophils and can be used to reduce the interference from this enzyme in assays of acid maltase.     

Characteristics of Inflammation-Induced Hypertrophy of Rat Intestinal Smooth Muscle Cell

Inflammation of the human intestine causesthickening of the smooth muscle layers, and studies inrats infected with Trichinella spiralis (Tsp) have shownhyperplasia of the intestinal smooth muscle cells (ISMC). We have shown that Tsp-inducedinflammation caused a fivefold increase in total proteinper ISMC over control, while ISMC from the noninflameddistal ileum also showed a threefold increase. The amount of -smooth muscle (SM) actin perISMC increased nearly 500% over control by postinfection(PI) day 6. The proportion of -SM actin in thetotal cellular protein increased 200% by day 6 PI, indicating a higher density of -SM actinin the hypertrophied ISMC. -SM actin mRNAincreased sharply and was matched by an increasedfractional content of -SM actin protein. Theseincreases in the smooth muscle-specific actins may affectforce production and further demonstrate the plasticityof smooth muscle in the inflamed intestine.     

Expression and prognostic roles of integrins and interleukin-1 receptor type I in patients with ductal adenocarcinoma of the pancreas

To Investigate the prognostic indicator, we examined the expression of ₆- and ₅- integrin and interleukin-1 receptor type I (IL-1RI) immunohistochemically, and analyzed the correlation between immunohistochemical findings and clinicopathological factors in pancreatic cancer. In patients with a strongly expressing ₆- integrin subunit or weakly expressing ₅₁-integrin in pancreatic cancer tissues there was a significant association with advanced TNM stage (P = 0.027 and 0.014, respectively), presence of liver metastases (P = 0.032 and 0.002, respectively), and poor prognosis (P = 0.0155 and 0.0056, respectively). In patients with a weakly expressing ₆ integrin subunit or weakly expressing ₅₁-integrin in noncancerous pancreatic tissues there was a significant association with poor prognosis (P = 0.0324 and 0.0396, respectively). Multivariate analysis demonstrated that strong expression of ₆- and weak expression of ₅₁-integrin were found to be independent prognosticators in pancreatic cancer patients. Our present results indicate that ₆₁- and ₅₁-integrin expression can be a significant prognostic indicator in pancreatic cancer.     

Low Endogenous Prostaglandin E2 Predisposes to Relapsing Inflammation in Experimental Rat Enterocolitis

Intramural injection ofpeptidoglycan-polysaccharide (PG-PS) induces acuteenterocolitis that spontaneously relapses in Lewis butnot Fischer rats. Interleukin-1 (IL-1) and tumornecrosisfactor- (TNF-) induce prostaglandin E₂(PGE₂) secretion, which inhibits secretion ofthese cytokines by macrophages, suggesting an inhibitoryfeedback mechanism. We postulate that Lewis ratsusceptibility to relapse is due to an imbalance betweenprotective prostaglandins and cytokines. Female Fischerand Lewis rats were injected with PG-PS (37.5 g/g)or human serum albumin intramurally. Tissue IL-1 and PGE₂ immunoreactivities andmyeloperoxidase (MPO) activity were determined.Relapsing rats had lower PGE₂ andPGE₂:IL-1 ratios than nonrelapsingrats (P < 0.05). In Fischer rats, 2 mg/kg/day indomethacinpotentiated cecal MPO and IL-1 concentrationsabove PG-PS alone (P < 0.05). Misoprostol treatmentblocked PG-PS-induced IL-1 and MPO and inhibited the potentiating effect of indomethacin on MPOand IL-1 (P < 0.05). In conclusion, increasedendogenous PG may be protective against relapsinginflammation in PG-PS induced enterocolitis, at least partially via inhibition of proinflammatorycytokines. An imbalance between protectiveprostaglandins and proinflammatory cytokines may beinvolved in the pathogenesis of chronic relapsinginflammation in genetically susceptible hosts.     

Temporal Expression of Tumor Necrosis Factor-α and Nitric Oxide Synthase 2 in Rat Small Intestine After Endotoxin

Temporal changes in tumor necrosis factor- (TNF-) and nitric oxide synthase 2 (NOS 2) were evaluated in segments of duodenum, jejunum, and ileum removed from male Sprague-Dawley rats 30, 60, 120, 180, and 240 min after lipopolysaccharide (LPS), 5 mg/kg, intreperitoneally. Plasma was assayed for TNF- and for nitrate/nitrite (NO_x). Intestinal and plasma TNF- were elevated by 60 min after LPS and were back to control levels by 180 min. For control rats, NOS 2 was detected in the ileum, but not in the duodenum or the jejunum. In rats treated with LPS, NOS 2 was detected in all areas of the intestine at 120 min and was greatest at 240 min. Plasma NO_x was elevated at 120 min and continued to increase to 240 min. The time course of changes in intestinal TNF- and NOS 2 were similar to those reported for other tissues and suggest that the early and late actions of the LPS on the intestine may involve both mediators.     

Enzymatic determination of serum 3α-sulfated bile acids concentration with bile acid 3α-sulfate sulfohydrolase

A newly developed enzymatic method for determining urinary 3-sulfated bile acids was used to measure serum 3-sulfated bile acid levels in 114 patients with hepatobiliary diseases and 56 healthy subjects. The lowest measurable amount of the 3-sulfated bile acids was 0.5 µmol/liter. The standard curves for glycolithocholic acid 3-sulfate, glycoursodeoxycholic acid 3-sulfate, and lithocholic acid 3-sulfate were linear from 0.5 to 250 µmol/liter. Specificity of the assay was satisfactory and intra- and interassay variations ranged from 0.8 to 4.4% and from 1.2 to 7.9%, respectively. Analytical recovery was more than 91%. The values obtained by this assay were well correlated with those by gas-liquid chromatography measurement (r=0.91,P<0.01). The fasting serum 3-sulfated bile acids level in healthy subjects ranged from undetectable to 1.9 µmol/liter (mean±se; 0.9±0.1 µmol/liter). The percentage of 3-sulfated bile acids in total bile acids (sum of 3-sulfated and 3-hydroxy bile acids) in serum was 16.8±1.5%. In subjects with hepatobiliary diseases, serum 3-sulfated bile acids levels were elevated; however, the percentage of 3-sulfated bile acids in total bile acids was decreased and correlated with the severity of hepatocellular insufficiency. This enzymatic assay is simple, rapid, and accurate for the determination of serum 3-sulfated bile acids.     

Triplication (/ααα<Superscript>Anti3.7</Superscript>) or deletion (-α<Superscript>3.7</Superscript>/) association in Argentinian β-thalassemic carriers

Prevalence of alpha gene triplication or deletion in -thalassemia carriers was studied in 109 unrelated individuals in Rosario, Argentina. In different populations -^3.7 allele presents a higher prevalence than ^anti3.7; thus, -thalassemia associated with -thalassemia is more frequently observed. Nevertheless, this event was detected in only one case (0.9%), while the association with alpha triplication was present in two subjects (1.8%).     

Impaired cytokine production in whole blood cell cultures of patients with urological carcinomas

The production of the cytokines interferon (IFN ), interleukin-1 (IL-1 ) and tumor necrosis factor (TNF ) was investigated in the mitogen-stimulated whole blood cell culture media from 51 patients with urinary bladder carcinomas, 52 patients with renal carcinomas, 31 patients with prostatic carcinomas and 360 healthy controls. The cytokines were measured 4 days after induction by a sensitive enzymo-immunological assay. In the blood cell culture supernatants of the patients with urinary bladder carcinomas significancy lower levels of IFN (P0.001), IL-2 (P0.001) and TNF (P0.05) were found as compared to the controls. Blood cells of patients with renal carcinomas had lower production of IFN (P0.01), IL-2 (P0.001) and IL-1 (P0.01), whereas the values of the total group of patients with prostatic carcinomas were not significantly different from those of the controls. Lymphocyte and monocyte counts were almost identical in the control and all tumor patient groups. When the patients with renal carcinomas and prostatic carcinomas were analyzed according to their different clinical stages we could show a gradual depression of the IFN- levels, which was related to tumor burden.Abbreviations PHA phytohemagglutinin - PWM pokeweed mitogen - ELISA enzyme-linked immunoassay - IL interleukin - IFN interferon - TNF tumor necrosis factor, mAb, monoclonal antibody     

Biliary Interleukin-6 and Tumor Necrosis Factor-α in Patients Undergoing Endoscopic Retrograde Cholangiopancreatography

Cytokines are low-molecular-weight proteinmediators that possess a wide spectrum of inflammatory,metabolic, and immunomodulatory properties. Cytokineshave been shown to be produced by monocytes/macrophages, lymphocytes, fibroblasts, endothelial cells,and more recently, hepatocytes and biliary epithelium.The aim of this study was to define biliary levels ofinterleukin-6 (IL-6) and tumor necrosis factor- (TNF-) in patients undergoing endoscopicretrograde cholangiopancreatography (ERCP) in variousdisease states. Fifty-four patients undergoing ERCPcomprised the study group. IL-6 and TNF- were measured in aspirated bile using an ELISAtechnique. Levels of both TNF- and IL-6 weresignificantly higher in patients with cholangitis (P< 0.00001). Moreover, IL-6 was 100% specific forcholangitis since none of the patients without bacterialcholangitis — including patients with biliaryobstruction secondary to cholangiocarcinoma orpancreatic carcinoma — had measurable IL-6 intheir bile. Low levels of biliary TNF- were detectable in fivepatients without cholangitis; the sensitivity andspecificity of TNF- for cholangitis were 100% and82%, respectively. There was a strong statisticalcorrelation between biliary IL-6 and TNF- levels (r= 0.819, P < 0.0001). In contrast, the correlationsbetween biliary cytokines and serum biochemicalparameters were weak. These results suggest that IL-6and TNF- are sensitive markers for cholangitis and maydifferentiate it from other types of biliary tractdisease.     

Low Endogenous Prostaglandin E2 Predisposes to Relapsing Inflammation in Experimental Rat Enterocolitis

Intramural injection of peptidoglycan-polysaccharide (PG-PS) induces acute enterocolitis that spontaneously relapses in Lewis but not Fischer rats. Interleukin-1 (IL-1) and tumor necrosis factor- (TNF-) induce prostaglandin E₂ (PGE₂) secretion, which inhibits secretion of these cytokines by macrophages, suggesting an inhibitory feedback mechanism. We postulate that Lewis rat susceptibility to relapse is due to an imbalance between protective prostaglandins and cytokines. Female Fischer and Lewis rats were injected with PG-PS (37.5 g/g) or human serum albumin intramurally. Tissue IL-1 and PGE₂ immunoreactivities and myeloperoxidase (MPO) activity were determined. Relapsing rats had lower PGE₂ and PGE₂/IL-1 ratios than nonrelapsing rats (P < 0.05). In Fischer rats, 2 mg/kg/day of indomethacin potentiated cecal MPO and IL-1 concentrations above PG-PS alone (P < 0.05). Misoprostol treatment blocked PG-PS induced IL-1 and MPO and inhibited the potentiating effect of indomethacin on MPO and IL-1 (P < 0.05). In conclusion, increased endogenous PG may be protective against relapsing inflammation in PG-PS induced enterocolitis, at least partially via inhibition of proinflammatory cytokines. Imbalance between protective prostaglandins and proinflammatory cytokines may be involved in the pathogenesis of chronic relapsing inflammation in genetically susceptible hosts.     

Effects of human α-interferon on granulocyte-macrophage progenitor cells (CFU-GM) in vitro

Summary Two preparations of human interferon (IFN)- were assessed for their influence on granulocyte-macrophage progenitor cells (CFU-GM) in vitro. Both highly purified human IFN- Ly and recombinant IFN- 2a suppressed CFU-GM colony formation in a dose-dependent manner using low-density bone-marrow target cells. Suppression of CFU-GM colony formation was accompanied by an increase in clusters. However, depletion of monocytes, T lymphocytes and B lymphocytes from low-density bone-marrow cells resulted in insensitivity of progenitor cells to IFN-. These results demonstrate that the effects of human IFN- on myeloid progenitor cells (CFU-GM) are mediated by accessory cells within the bone marrow.     

Hb Cemenelum [α92 (FG4) Arg→Trp]: A hemoglobin variant of theα1/β2 interface that displays a moderate increase in oxygen affinity

Summary Hb Cemenelum [92 (FG4) ArgTrp] carries a structural modification at the same position as Hb Chesapeake, a very high oxygen affinity variant. Hb Cemenelum was found in a French diabetic patient with no abnormal hematological features. The purified abnormal hemoglobin, like Hb J Cape Town, another variant of position 92(FG4), displayed only a 1.5-to 2-fold increased oxygen affinity and a reduced cooperativity. This hemoglobin demonstrates that, even for some key residues of the1/2 interface, the degree at which the functional properties are altered depends upon the specific residue occupying this position.