Postoperative pulmonary complications, pulmonary and systemic inflammatory responses after lung resection surgery with prolonged one-lung ventilation. Randomized controlled trial comparing intravenous and inhalational anaesthesia.

BACKGROUND: Recent studies report the immunomodulatory lung-protective role of halogenated anaesthetics during lung resection surgery (LRS) but have not investigated differences in clinical postoperative pulmonary complications (PPCs). The main goal of the present study was to compare the effect of sevoflurane and propofol on the incidence of PPCs in patients undergoing LRS. The second aim was to compare pulmonary and systemic inflammatory responses to LRS. METHODS: Of 180 patients undergoing LRS recruited, data from 174 patients were analysed. Patients were randomized to two groups (propofol or sevoflurane) and were managed otherwise using the same anaesthetic protocol. Bronchoalveolar lavage (BAL) was performed in both lungs before and after one-lung ventilation for analysis of cytokines. Arterial blood was drawn for measurement of the cytokines analysed in the BAL fluid at five time points. Intraoperative haemodynamic and respiratory parameters, PPCs (defined following the ARISCAT study), and mortality during the first month and yr were recorded. RESULTS: More PPCs were detected in the propofol group (28.4% vs 14%, OR 2.44 [95% CI, 1.14-5.26]). First-yr mortality was significantly higher in the propofol group (12.5% vs 2.3%, OR 5.37 [95% CI, 1.23-23.54]). Expression of lung and systemic pro-inflammatory cytokines was greater in the propofol group than in the sevoflurane group. Pulmonary and systemic IL-10 release was less in the propofol group. CONCLUSIONS: Our results suggest that administration of sevoflurane during LRS reduces the frequency of the PPCs recorded in our study and attenuates the pulmonary and systemic inflammatory response. CLINICAL TRIAL REGISTRATION: NCT 02168751; EudraCT 2011-002294-29.

Reduced apurinic/apyrimidinic endonuclease 1 activity and increased DNA damage in mitochondria are related to enhanced apoptosis and inflammation in the brain of senescence- accelerated P8 mice (SAMP8).

The senescence- accelerated mouse prone 8 (SAMP8) is a well- characterized animal model of senescence that shows early age- related neurodegeneration with impairment in learning and memory skills when compared with control senescence- resistant mice (SAMR1). In the current study, we investigated whether such impairment could be partly due to changes in mitochondrial DNA (mtDNA) repair capacity and mitochondrial DNA damage in the brain of SAMP8 mice. Besides we studied whether these potential changes were related to modifications in two major processes likely involved in aging and neurodegeneration: apoptosis and inflammation. We observed that the specific activity of one of the main mtDNA repair enzymes, the mitochondrial APE1, showed an age- related reduction in SAMP8 animals, while in SAMR1 mice mitochondrial APE1 increased with age. The reduction in mtAPE1 activity in SAMP8 animals was associated with increased levels of the DNA oxidative damage marker 8oxodG in mtDNA. Our results also indicate that these changes were related to a premature increase in apoptotic events and inflammation in the brain of SAMP8 mice when compared to SAMR1 counterparts. We suggest that the premature neurodegenerative phenotype observed in SAMP8 animals might be due, at least in part, to changes in the processing of mtDNA oxidative damage, which would lead to enhancement of apoptotic and inflammatory processes.

Growth hormone and melatonin prevent age-related alteration in apoptosis processes in the dentate gyrus of male rats.

It has been suggested that the age-related decrease in the number of neurons in the hippocampus that leads to alterations in brain function, may be associated with an increase in apoptosis due to the reduced secretion of growth hormone (GH) and/or melatonin in old animals. In order to investigate this possibility, male Wistar rats of 22 months of age were divided into three groups. One group remained untreated and acted as the control group. The second was treated with growth hormone (hGH) for 10 weeks (2 mg/kg/d sc) and the third was subjected to melatonin treatment (1 mg/kg/d) in the drinking water for the same time. A group of 2-months-old male rats was used as young controls. All rats were killed by decapitation at more than 24 month of age and dentate gyri of the hippocampi were collected. Aging in the dentate gyrus was associated with an increase in apoptosis promoting markers (Bax, Bad and AIF) and with the reduction of some anti-apoptotic ones (XIAP, NIAP, Mcl-1). Expressions of sirtuin 1 and 2 (SIRT1 and 2) as well as levels of HSP 70 were decreased in the dentate gyrus of old rats. GH treatment was able to reduce the pro/anti-apoptotic ratio to levels observed in young animals and also to increase SIRT2. Melatonin reduced also expression of pro-apoptotic genes and proteins (Bax, Bad and AIF), and increased levels of myeloid cell leukemia-1 proteins and SIRT1. Both treatments were able to reduce apoptosis and to enhance survival markers in this part of the hippocampus.

Effect of estrogens on base excision repair in brain and liver mitochondria of aged female rats.

Changes in the endocrine system have been suggested to act as signaling factors in the regulation of age-related events. Among the different hormones that have been linked to the aging process, estrogens have been widely investigated. They have been associated with inflammatory and oxidative processes and several investigations have established a relationship between the protective effects of estrogens and the mitochondrial function. Mitochondrial DNA is subjected to continuous oxidative attack by free radicals, and the base excision repair (BER) pathway is the main DNA repair route present in mitochondria. We have investigated the effect of estrogen levels on some of the key enzymes of BER in brain and liver mitochondria. In both tissues, depletion of estrogens led to an increased mitochondrial AP endonuclease (mtAPE1) activity, while restoration of estrogen levels by exogenous supplementation resulted in restitution of control APE1 activity only in liver. Moreover, in hepatic mitochondria, changes in estrogen levels affected the processing of oxidative lesions but not deaminations. Our results suggest that changes in mtAPE1 activity are related to specific translocation of the enzyme from the cytosol into the mitochondria probably due to oxidative stress changes as a consequence of changes in estrogen levels.

Cardiological aging in SAM model: effect of chronic treatment with growth hormone.

The purpose of this study was to investigate the effect of aging on different parameters related to inflammation, oxidative stress and apoptosis in hearts from two types of male mice models: senescence-accelerated mice (SAM-P8) and senescence-accelerated-resistant (SAM-R1), and the influence of chronic administration of Growth Hormone (GH) on old SAM-P8 mice. Forty male mice were used. Animals were divided into five experimental groups: two 10 month old untreated groups (SAM-P8/SAM-R1), two 2 month old young groups (SAM-P8/SAM-R1) and one 10 month old group (SAM-P8) treated with GH for 30 days. The expression of tumor necrosis factor-alpha, interleukin 1, interleukin 10, heme oxygenases 1 and 2, endothelial and inducible nitric oxide synthases, NFkB, Bad, Bax and Bcl-2 were determined by real-time reverse transcription polymerase chain reaction (RT-PCR). Results were submitted to a two way ANOVA statistical evaluation using the Statgraphics program. Inflammation, as well as, oxidative stress and apoptosis markers were increased in the heart of old SAM-P8 males, as compared to young controls and this situation was not observed in the old SAM-R1 mice. Exogenous GH administration reverted the effect of aging in the described parameters of old SAM-P8 mice. Our results suggest that inflammation, apoptosis and oxidative stress could play an important role in the observed cardiovascular alterations related to aging of SAM-P8 mice and that GH may play a potential protective effect on the cardiovascular system of these animals.

Hormonal regulation of pro-inflammatory and lipid peroxidation processes in liver of old ovariectomized female rats.

There is now a large body of evidence suggesting that the decline in ovarian function with menopause is associated with spontaneous increases in pro-inflammatory cytokines. On the other hand, oxidative stress has been implicated in the pathogenesis of several alterations due to menopause, and can arise through the increased production of lipid peroxides (LPO) and/or a deficiency of antioxidant defense. The aim of the present study was to investigate the effect of aging and ovariectomy on various physiological parameters related to inflammation and oxidative stress in livers obtained from old female rats and the influence of chronic exogenous administration of estrogens, phytoestrogens and growth hormone on these. Thirty-six female Wistar rats of 22 months of age were used in the present study. Twelve of them remained intact, and the other 24 had been ovariectomized at 12 months of age. Intact animals were divided into two groups and treated for 10 weeks with GH or saline, and ovariectomized animals were divided into four groups and treated for the same time with GH, estrogens, phytoestrogens or saline. A group of 2 month old intact female rats was used as young control. Protein expression of iNOS, HO-1, IL-6, TNFalpha, and IL-1beta were determined by Western blot analysis. The levels of NO( x ), LPO, TNFalpha, IL-1beta, IL-6 and IL-10 were determined in different fractions of the liver. Levels of LPO in the liver homogenates as well as iNOS protein expression and NO( x ) levels were increased in old rats as compared to young animals; this effect was more evident in ovariectomized animals. Pro-inflammatory cytokines TNF-alpha, IL-1beta and IL-6 were significantly increased and anti-inflammatory IL-10 decreased during ageing and after ovariectomy. Aging also significantly increased expression of HO-1 protein and ovariectomized rats showed an additional increase. Hormonal administration to the ovariectomized groups decreased NO( x ), LPO levels and pro-inflammatory cytokines as compared with untreated rats. Significant rise in IL-10 and reductions in the iNOS, IL-6, TNFalpha and IL-1beta proteins expression were also found. Oxidative stress and inflammation induced during aging in the liver are more marked in castrated than in intact old females. Administration of the different hormonal replacement therapies was able to inhibit the induction of pro-inflammatory cytokines and iNOS, decreased the levels of oxidative stress markers and had therapeutic potential in the prevention of liver injury.

The ß2-adrenergic receptor antagonist ICI-118,551 blocks the constitutively activated HIF signalling in hemangioblastomas from von Hippel-Lindau disease.

One of the major consequences of the lack of a functional VHL protein in von Hippel-Lindau disease, a rare cancer, is the constitutive activation of the HIF pathway. This activation ends up in the generation of Central Nervous System (CNS) Hemangioblastomas among other tumours along the lifespan of the patient. Nowadays, only surgery has been proven efficient as therapy since the systemic attempts have failed. Propranolol, a non-specific ß1-and ß2-adrenergic receptor antagonist, was recently designated as the first therapeutic (orphan) drug for VHL disease. Nevertheless, its ß1 affinity provokes the decrease in blood pressure, being not recommended for low or regular blood pressure VHL patients. In order to overcome the ß1-drawback, the properties of a high specific ß2-adrenergic receptor blocker named ICI-118,551 have been studied. ICI-118,551 was able to decrease Hemangioblastomas cell viability in a specific manner, by triggering apoptosis. Moreover, ICI-118,551 also impaired the nuclear internalization of HIF-1α in Hemangioblastomas and hypoxic primary endothelial cells, reducing significantly the activation of HIF-target genes and halting the tumour-related angiogenic processes. In this work, we demonstrate the therapeutical properties of ICI-118,551 in VHL-derived CNS-Hemangioblastoma primary cultures, becoming a promising drug for VHL disease and other HIF-related diseases.

Melatonin is able to prevent the liver of old castrated female rats from oxidative and pro-inflammatory damage.

The aim of this study was to investigate the effect of aging and ovariectomy on various physiological parameters related to inflammation and oxidative stress in livers obtained from old female rats, and the influence of chronic administration of melatonin on these animals. Twenty-four female Wistar rats of 22 months of age were used. Animals were divided into four experimental groups: two intact groups that were untreated or given melatonin (1 mg/kg/day), and two ovariectomized groups that also untreated and treated with melatonin (1 mg/kg/day). After 10 wk of treatment, rats were sacrificed by decapitation, and livers were collected and homogenized. A group of 2-month-old female rats was used as young controls. Protein expression of inducible nitric oxide synthase (iNOS), heme oxygenase-1 (HO-1), IL-6, TNF-alpha and IL-1beta were determined by Western blot analysis. The levels of nitric oxide metabolites (NO(x)), lipid hydroperoxide (LPO), TNF-alpha, IL-1beta, IL-6 and IL-10 were determined. Levels of LPO in the liver homogenates as well as iNOS protein expression and NO(x) levels were increased in old rats as compared with young animals; this effect was more evident in ovariectomized animals. Pro-inflammatory cytokines TNF-alpha, IL-1beta and IL-6 were significantly increased and anti-inflammatory IL-10 decreased during aging and after ovariectomy. Aging also significantly increased the expression of HO-1 protein, and ovariectomized rats showed an additional increase. Administration of melatonin, both to intact and to the ovariectomized animals significantly reduced NO(x), LPO levels and pro-inflammatory cytokines in the liver as compared with untreated rats. Significant rice in IL-10 and reductions in the iNOS, HO-1, IL-6, TNF-alpha and IL-1beta protein expression were also found in rats treated with melatonin. Oxidative stress and inflammation induced during aging in the liver are more marked in castrated than in intact females. Administration of melatonin reduces both these situations.

Prehepatic portal hypertension worsens the enterohepatic redox balance in thioacetamide-cirrhotic rats.

BACKGROUND: Oxidative stress has been reported as a key pathogenic factor in many human liver diseases and in experimental models of cirrhosis related to hepatotoxin administration. The aim of this study was to verify the hypothesis that prehepatic portal hypertension aggravates the enterohepatic redox imbalance in thioacetamide-cirrhotic rats. MATERIALS AND METHODS: Wistar male rats were used: Control (n=9); rats with prehepatic portal hypertension by triple partial portal vein ligation (TPVL; n=9); thioacetamide-cirrhotic rats (TAA; n=9) and TPVL-rats associated to TAA administration (TPVL+TAA; n=9). Three months after the operation, portal pressure (PP), mesenteric venous vasculopathy (MVV) and portosystemic collateral circulation were studied. Liver and ileal levels of malondialdehyde (MDA), as a lipid peroxidation marker, and catalase (CAT), glutathione peroxidase (GSH-Px), glutathione transferase (GSH-t) and cytosolic and mitochondrial superoxide dismutases (cSOD and mSOD), as antioxidative enzymatic mechanisms, were measured. RESULTS: Liver and ileal MDA increased in all the experimental groups, although the higher increase occurred in the ileum of rats with portal hypertension. CAT levels decreased in the liver and the ileum in the three experimental groups. The decrease in liver and ileal GSH-Px and GSH-t was greater in rats with portal hypertension, alone or associated with TAA. mSOD activation was demonstrated in the liver when portal hypertension was added to TAA. On the contrary, this compensatory response was not activated in the ileum, where mSOD was significantly decreased. CONCLUSION: Prehepatic portal hypertension by triple partial portal vein ligation impaired the enterohepatic antioxidative activity and aggravated the intestinal oxidative stress in thioacetamide-cirrhotic rats.

Tumor necrosis factor-alpha-induced inhibition of phosphatidylcholine synthesis by human type II pneumocytes is partially mediated by prostaglandins.

TNF alpha seems to play an important role in the pathogenesis of adult respiratory distress syndrome. We studied the effect of TNF alpha on phospholipid synthesis by isolated type II pneumocytes and attempted to characterize the role of arachidonate metabolites and the influence of pentoxifylline on such an effect. Lung tissue obtained from both multiple organ donors (n = 14) and lung cancer patients (n = 11) was used for cell isolation. Surfactant synthesis was measured by the incorporation of D-[U-14C]glucose into phosphatidylcholine (PC). The basal PC synthesis was higher in the donor group than in the malignant group (3.44 +/- 0.19 vs 2.15 +/- 0.15 pmol/microgram protein x 120 min, P < 0.01), and, in the presence of 100 ng/ml of TNF alpha, the incorporation of labeled glucose into PC was reduced significantly in both donor (1.13 +/- 0.11 vs 3.44 +/- 0.19 pmol/microgram protein x 120 min, P < 0.01) and cancer (0.99 +/- 0.11 vs 2.15 +/- 0.15 pmol/microgram protein x 120 min, P < 0.01) groups. Indomethacin was able to completely block the cytokine-induced decrease in PC synthesis by pneumocytes from the malignant group and to attenuate the inhibitory effect of TNF alpha in those from donors, nordihydroguaiaretic acid having a similar effect. The TNF alpha effect can be blocked by pentoxifylline (100 micrograms/ml), a substance which can even succeed in reverting the basal secretory inhibition of cancer patients' pneumocytes to levels similar to those of the donor group. TNF alpha may contribute to the pathophysiology of adult respiratory distress syndrome by inhibiting the synthesis of surfactant. TNF alpha might be produced in lung tumors, resulting in chronic paracrine or systemic exposure of pneumocytes to low concentrations of the cytokine. The TNF alpha effect was not prevented completely by the blockage of the arachidonic acid metabolism, hence other mediators should also be implicated.

Efficacy of albendazole against Anisakis simplex larvae in vitro.

BACKGROUND: The growing popularity in western countries of eating uncooked seafood has resulted in an increased incidence of anisakidosis. AIM: To study the in vitro activity of different concentrations of albendazole against Anisakis simplex larvae under different media pH. METHODS: A. simplex larvae were obtained from fresh hakes acquired from the fish market of Madrid. They were divided into groups and placed in culture dishes (15 larvae each) containing RPMI-1640, in the presence or absence of different concentrations of albendazole (300, 400 and 500 microg/mL). RESULTS: Albendazole dose-dependently reduced the survival of the larvae, its maximum activity being at 500 microg/mL when it killed almost all larvae at 48 h. Acidic medium pH significantly reduced the efficacy of albendazole. CONCLUSION: Albendazole is effective in killing A. simplex larvae at different pH in vitro, suggesting that this molecule could be useful in treating clinical manifestations of human anisakidosis.

Influence of aging and growth hormone on different members of the NFkB family and IkB expression in the heart from a murine model of senescence-accelerated aging.

Inflammation is related to several pathological processes. The aim of this study was to investigate the protein expression of the different subunits of the nuclear factor Kappa b (NFkBp65, p50, p105, p52, p100) and the protein expressions of IkB beta and alpha in the hearts from a murine model of accelerated aging (SAM model) by Western blot. In addition, the translocation of some isoforms of NFkB from cytosol to nuclei (NFkBp65, p50, p52) and ATP level content was studied. In addition we investigated the effect of the chronic administration of growth hormone (GH) on these age-related parameters. SAMP8 and SAMR1 mice of 2 and 10 months of age were used (n = 30). Animals were divided into five experimental groups: 2 old untreated (SAMP8/SAMR1), 2 young control (SAMP8/SAMR1) and one GH treated-old groups (SAMP8). Age-related changes were found in the studied parameters. We were able to see decreases of ATP level contents and the translocation of the nuclear factor kappa B p50, p52 and p65 from cytosol to nuclei in old SAMP8 mice together with a decrease of IKB proteins. However p100 and p105 did not show differences with aging. No significant changes were recorded in SAMR1 animals. GH treatment showed beneficial effects in old SAMP8 mice inducing an increase in ATP levels and inhibiting the translocation of some NFkB subunits such as p52. Our results supported the relation of NFkB activation with enhanced apoptosis and pro-inflammatory status in old SAMP8 mice and suggested a selective beneficial effect of the GH treatment, which was able to partially reduce the incidence of some deleterious changes in the heart of those mice.

Molecular characterisation of a versatile peroxidase from a Bjerkandera strain.

The cloning and sequencing of the rbpa gene coding for a versatile peroxidase from a novel Bjerkandera strain is hereby reported. The 1777 bp isolated fragment contained a 1698 bp peroxidase-encoding gene, interrupted by 11 introns. The 367 amino acid-deduced sequence includes a 27 amino acid-signal peptide. The molecular model, built via homology modelling with crystal structures of four fungal peroxidases, highlighted the amino acid residues putatively involved in manganese binding and aromatic substrate oxidation. The potential heme pocket residues (R44, F47, H48, E79, N85, H177, F194 and D239) include both distal and proximal histidines (H48 and H177). RBP possesses potential calcium-binding residues (D49, G67, D69, S71, S178, D195, T197, I200 and D202) and eight cysteine residues (C3, C15, C16, C35, C121, C250, C286, C316). In addition, RBP includes residues involved in substrate oxidation: three acidic residues (E37, E41 and D183)--putatively involved in manganese binding and H83 and W172--potentially involved in oxidation of aromatic substrates. Characterisation of nucleotide and amino acid sequences include RBP in versatile peroxidase group sharing catalytic properties of both LiP and MnP. In addition, the RBP enzyme appears to be closely related with the ligninolytic peroxidases from the Trametes versicolor strain.

Microflora evaluation of two agro-industrial effluents treated by the JACTO jet-loop type reactor system.

Jet-loop type reactors developed in our group have been successfully used for biological treatment of winery and olive oil wastewaters. The objective of the present work was to study the influence of the reactor hydrodynamics, causing high shear stress applied on the nozzle and its influence on the composition of the microbial population. Winery and olive oil industry effluents were treated and analysed. Microbial consortia were enriched and selected under different bio-treatment conditions of the effluents. In the case of the winery wastewaters, the isolates identified belong to the genera of Pseudomonas and Bacillus. Saccharomyces cerevisiae was also present in the consortia but no filamentous fungi were detected. In the case of the olive oil wastewaters, Bacillus megaterium 2 was the predominant microorganism. It was not detected any type of fungi.

Intervention study for smoking cessation in diabetic patients: a randomized controlled trial in both clinical and primary care settings.

OBJECTIVE: To evaluate the effectiveness of a nurse-managed smoking cessation intervention in diabetic patients. RESEARCH DESIGN AND METHODS: This randomized controlled clinical trial involved 280 diabetic smokers (age range 17-84 years) who were randomized either into control (n = 133) or intervention (n = 147) groups at 12 primary care centers and 2 hospitals located in Navarre, Spain. The intervention consisted of a 40-min nurse visit that included counseling, education, and contracting information (a negotiated cessation date). The follow-up consisted of telephone calls, letters, and visits. The control group received the usual care for diabetic smokers. Baseline and 6-month follow-up measurements included smoking status (self-reported cessation was verified by urine cotinine concentrations), mean number of cigarettes smoked per day, and stage of change. RESULTS: At the 6-month follow-up, the smoking cessation incidence was 17.0% in the intervention group compared with 2.3% in the usual care group, which was a 14.7% difference (95% CI 8.2-21.3%). Among participants who continued smoking, a significant reduction was evident in the average cigarette consumption at the 6-month follow-up. The mean number of cigarettes per day decreased from 20.0 at baseline to 15.5 at 6 months for the experimental group versus from 19.7 to 18.1 for the control group (P < 0.01). CONCLUSIONS: A structured intervention managed by a single nurse was shown to be effective in changing the smoking behavior of diabetic patients.

Effects of L-leucine on palmitate metabolism and insulin release by isolated islets of fed and starved rats.

The occurrence of lipid metabolic changes associated with L-leucine (10 mM) stimulation of insulin release was investigated in isolated islets from either fed or starved rats. L-Leucine-stimulated secretion was potentiated by 3 mM glucose and/or 0.5 mM palmitate and was unaffected by 48 h of starvation. Islet palmitate oxidation showed a maximum rate at 3 mM glucose, and starvation increased it almost 2-fold. Regardless of the nutritional state, L-leucine strongly reduced the oxidation of palmitate and increased its incorporation into islet triacylglycerols and phospholipids at 3 mM glucose. This shift of fatty acid metabolism toward esterification might play a role in the mechanism of potentiation of the islet secretory response to L-leucine by glucose and palmitate.

Effects of endotoxin lipopolysaccharide administration on the somatotropic axis.

The aim of this work was to study the effect of chronic activation of the immune system on the somatotropic axis. Accordingly, the changes in growth hormone (GH) secretion, circulating insulin-like growth factor-I (IGF-I) and IGF binding proteins (IGFBPs) in response to endotoxin lipopolysaccharide (LPS) administration were examined in adult male Wistar rats. Acute LPS injection (2.5, 25 or 250 microg/kg) increased serum corticosterone in a dose-dependent manner and decreased serum levels of insulin and IGF-I, serum GH concentration declined linearly as the LPS dose increased. Western ligand blot showed an increase in the 33 kDa band (corresponding to IGFBP-1 and IGFBP-2) in the rats that received the highest dose of LPS (250 microg/kg). Chronic LPS administration (250 microg/kg daily for 8 days) significantly decreased body weight, serum levels of IGF-I and pituitary GH content, whereas it increased circulating IGFBP-3 (47 kDa band), IGFBP-1 and IGFBP-2 (33 kDa band) and the 24 kDa band (which possibly corresponds to IGFBP-4). Serum concentration of corticosterone and hypothalamic somatostatin content were also increased by chronic LPS treatment. These data suggest that the decrease in GH and IGF-I secretion and the increase in circulating IGFBPs are important mechanisms in body weight loss during chronic inflammation.

Effect of surfactant protein A (SP-A) on the production of cytokines by human pulmonary macrophages.

Surfactant protein A (SP-A) is thought to play a role in the modulation of lung inflammation during acute respiratory distress syndrome (ARDS). However, SP-A has been reported both to stimulate and to inhibit the proinflammatory activity of pulmonary macrophages (Mphi). Because of the interspecies differences and heterogeneity of Mphi subpopulations used may have influenced previous controversial results, in this study, we investigated the effect of human SP-A on the production of cytokines and other inflammatory mediators by two well-defined subpopulations of human pulmonary Mphi. Surfactant and both alveolar (aMphi) and interstitial (iMphi) macrophages were obtained from multiple organ donor lungs by bronchoalveolar lavage and enzymatic digestion. Donors with either recent history of tobacco smoking, more than 72 h on mechanical ventilation, or any radiological pulmonary infiltrate were discarded. SP-A was purified from isolated surfactant using sequential butanol and octyl glucoside extractions. After 24-h preculture, purified Mphi were cultured for 24 h in the presence or absence of LPS (10 microg/mL), SP-A (50 microg/mL), and combinations. Nitric oxide and carbon monoxide (CO) generation (pmol/microg protein), cell cGMP content (pmol/microg protein), and tumor necrosis factor alpha (TNFalpha), interleukin (IL)-1, and IL-6 release to the medium (pg/microg protein) were determined. SP-A inhibited the lipopolysaccharide (LPS)-induced TNFalpha response of both interstitial and alveolar human Mphi, as well as the IL-1 response in iMphi. The SP-A effect on TNFalpha production could be mediated by a suppression in the LPS-induced increase in intracellular cGMP. In iMphi but not in aMphi, SP-A also inhibited the LPS-induced IL-1 secretion and CO generation. These data lend further credit to a physiological function of SP-A in regulating alveolar host defense and inflammation by suggesting a fundamental role of this apoprotein in limiting excessive proinflammatory cytokine release in pulmonary Mphi during ARDS.

Glucose stimulation of insulin secretion in islets of fed and starved rats and its dependence on lipid metabolism.

The influence of a physiologic range of palmitate concentrations (0, 0.25, 0.5, and 1.0 mmol/L) on glucose ability to modify insulin secretion, (U-14C) palmitate oxidation, and (U-14C) glucose incorporation into lipids has been studied in islets isolated from either fed or 48-hour starved rats. Palmitate potentiated the insulin response of fed islets to glucose in a particular dose-related manner. Glucose stimulated secretion was accompanied by a decreased palmitate oxidation and an increased (U-14C) glucose incorporation into di-, tri-acylglycerols, and predominantly into phospholipids. These metabolic parameters showed also a positive dependence on palmitate concentration. Starvation increased islet capacity to oxidize palmitate, rendered it insensitive to glucose inhibition, and inhibited both (U-14C) glucose incorporation into all lipid fractions and sugar induced insulin release. The stimulation of islet lipid synthesis by glucose seems to be limited by the exogenous supply of fatty acids and their rate of oxidation. As judged from (U-14C) glucose incorporation data, the rate of phospholipid biosynthesis showed a significant and positive correlation with insulin secretion. This metabolic pathway might provide islet cells with some lipid intermediates (diacylglycerol and/or specific phospholipids) that have been considered as possible mediators of the calcium messenger system.

Both prostaglandin E2 and nitric oxide sequentially mediate the tumor necrosis factor alpha-induced inhibition of surfactant synthesis by human type II pneumocytes.

BACKGROUND: Tumor necrosis factor alpha (TNF-alpha)-induced inhibition of surfactant synthesis seems to participate in the pathogenesis of the adult respiratory distress syndrome. OBJECTIVES: To examine the ability of human type II pneumocytes to produce nitric oxide (NO) in the presence of TNF-alpha and, in addition, to explore the role of this radical in the transduction of the cytokine signal. DESIGN: Multiple organ donors were the source of lung tissue specimens. Type II pneumocytes were isolated by enzymatic digestion, adherence separation of macrophages, and gradient purification. After 24-hour preculture, cells were cultured for 24 hours in the presence or absence of TNF-alpha (100 ng/mL), sodium nitroprusside (100 mumol/L), N omega-nitro-L-arginine methyl ester (NAME) (1 mmol/L), methylene blue (10 mumol/L),8-bromo-3',5'-cyclic guanosine monophosphate (8-Br-cGMP) (1 mmol/L), prostaglandin E2 (PGE2) (0.1 mumol/L), indomethacin (30 mumol/L), and combinations. The NO release to the medium and cGMP and PGE2 contents of the cells were measured. RESULTS: The incorporation of 14C-labeled glucose (D-[U-14C]glucose) into phosphatidylcholine and phosphatidylglycerol was selectively inhibited either by 8-Br-cGMP or in the presence of TNF-alpha, PGE2, or nitroprusside, all of which caused an increase in the intracellular levels of cGMP. The inhibitory effect of TNF-alpha was partially reverted by indomethacin, NAME, N-monomethyl arginine, or methylene blue. The inhibitory effect of PGE2 was partially reverted by NAME, while that of nitroprusside was reverted by methylene blue, but not by indomethacin. Tumor necrosis factor alpha induced an increase in PGE2 (4.31 +/- 0.27 vs 1.65 +/- 0.17-pg/microgram protein, n = 10, P < .01) and cGMP (0.238 +/- 0.012 vs 0.109 +/- 0.014-pmol/microgram protein, n = 10, P < .01) cell content and in the NO release to the medium (3.10 +/- 0.14 vs 1.19 +/- 0.11-nmol/microgram protein, n = 10, P < .01). The basal NO release to the medium was also increased in the presence of PGE2. The NAME, which blocked NO generation and cGMP increase, did not affect PGE2 production in response to TNF-alpha. However, indomethacin, which blocked PGE2 production, also blunted NO generation and cGMP increase. CONCLUSIONS: The NO generation, secondary to PGE2 production, seems responsible for the TNF-alpha-induced inhibition of phosphatidylcholine synthesis by human type II pneumocytes. Nitric oxide seems to exert this effect through activation of guanylyl cyclase.