Activity Of Peritoneal Macrophages Research Articles

Use of gold nanoparticles for the preparation of antibodies to tuberculin, the immunoassay of mycobacteria, and animal vaccination

We describe a new approach to preparing antibodies to tuberculin with the use of the adjuvant properties of gold nanoparticles (GNPs). This approach makes it possible to obtain antibodies that detect 0.78 ng of tuberculin. The specificity and sensitivity of the antibodies are characterized. It is shown that GNPs conjugated with tuberculin affect the respiratory and bactericidal activities of peritoneal macrophages. The antibodies are proposed for use in the immunodiagnostics of tuberculosis mycobacteria by solid-phase, light microscopic, and electron microscopic assays. We present results indicating that the vaccination of guinea pigs with tuberculin-GNP conjugates demonstrates a certain protective effect.

Purification, characterization and bioactivity of polysaccharides from Glossaulax didyma

In this study, purification, preliminary characterization, immunostimulatory and hepatoprotective activities of polysaccharides from Glossaulax didyma (GDPS) were investigated. Firstly, crude GDPS was purified by chromatography of DEAE-52 and Sephadex G-100, resulting in three purified fractions of GDPS-1, GDPS-2 and GDPS-3. The three fractions were mainly composed of glucose with the average molecular weight of 161, 197 and 204kDa, respectively. GDPS-2 was quite different from GDPS-1 or GDPS-3. It had much higher contents of protein and sulfuric radical. For immunostimulatory activities in vitro, the three fractions could significantly stimulate the proliferation of splenocytes and enhance phagocytic activity of peritoneal macrophages. For hepatoprotective activity in vivo, the administration of GDPS significantly decreased the serum levels of alanine aminotransferase, aspartate aminotransferase and tumor necrosis factor-alpha, inhibited the formation of malondialdehyde and restored the liver activities of superoxide dismutase and glutathione peroxidase in Bacillus Calmette-Guerin/lipopolysaccharide-induced liver injury mice. The results suggested GDPS should be a potent natural polymer with immunostimulatory and hepatoprotective activities.

Penta‐O‐galloyl‐β‐D‐glucose ameliorates inflammation by inhibiting MyD88/NF‐κB and MyD88/MAPK signalling pathways

The gallnut of Rhus chinensis MILL and its main constituent penta-O-galloyl-β-D-glucose (PGG) inhibited NF-κB activation in LPS-stimulated peritoneal and colonic macrophages. Here we have investigated PGG mechanisms underlying anti-inflammatory effects of PGG in vitro and in vivo. Male C57BL/6 mice (18-22 g, 6 weeks old) were used to prepare peritoneal and colonic macrophages and for the induction of colitis by intrarectal administration of 2,3,4-trinitrobenzene sulphonic acid (TNBS). A range of inflammatory markers and transcription factors were evaluated by elisa, immunoblotting, flow cytometry and confocal microscopy. Expression of Toll-like receptor (TLR)-4 or Lipopolysaccharide (LPS) binding to TLR-4 in LPS-stimulated peritoneal macrophages was not affected by PGG. However PGG inhibited binding of an anti-MyD88 antibody to peritoneal macrophages, but did not reduce binding of anti-IL-1 receptor-associated kinase (IRAK1) and IRAK4 antibodies to the macrophages with or without transfection with MyD88 siRNA. PGG potently reduced the activation of IRAK1, NF-κB, and MAPKs in LPS- or pepetidoglycan-stimulated peritoneal and colonic macrophages. PGG suppressed IL-1β, TNF-α and IL-6 in LPS-stimulated peritoneal macrophages, while increasing expression of the anti-inflammatorycytokine IL-10. Oral administration of PGG inhibited colon shortening and myeloperoxidase activity in mice with TNBS-induced colitis, along with reducing NF-κB activation and IL-1β, TNF-α, and IL-6 levels, whereas it increased IL-10. PGG reduced activation of NF-κB and MAPK signalling pathways by directly interacting with the MyD88 adaptor protein. PGG may ameliorate inflammatory diseases such as colitis.

Lysophosphatidylcholine Triggers TLR2- and TLR4-Mediated Signaling Pathways but Counteracts LPS-Induced NO Synthesis in Peritoneal Macrophages by Inhibiting NF-κB Translocation and MAPK/ERK Phosphorylation

BackgroundLysophosphatidylcholine (LPC) is the main phospholipid component of oxidized low-density lipoprotein (oxLDL) and is usually noted as a marker of several human diseases, such as atherosclerosis, cancer and diabetes. Some studies suggest that oxLDL modulates Toll-like receptor (TLR) signaling. However, effector molecules that are present in oxLDL particles and can trigger TLR signaling are not yet clear. LPC was previously described as an attenuator of sepsis and as an immune suppressor. In the present study, we have evaluated the role of LPC as a dual modulator of the TLR-mediated signaling pathway.Methodology/Principal FindingsHEK 293A cells were transfected with TLR expression constructs and stimulated with LPC molecules with different fatty acid chain lengths and saturation levels. All LPC molecules activated both TLR4 and TLR2-1 signaling, as evaluated by NF-қB activation and IL-8 production. These data were confirmed by Western blot analysis of NF-қB translocation in isolated nuclei of peritoneal murine macrophages. However, LPC counteracted the TLR4 signaling induced by LPS. In this case, NF-қB translocation, nitric oxide (NO) synthesis and the expression of inducible nitric oxide synthase (iNOS) were blocked. Moreover, LPC activated the MAP Kinases p38 and JNK, but not ERK, in murine macrophages. Interestingly, LPC blocked LPS-induced ERK activation in peritoneal macrophages but not in TLR-transfected cells.Conclusions/SignificanceThe above results indicate that LPC is a dual-activity ligand molecule. It is able to trigger a classical proinflammatory phenotype by activating TLR4- and TLR2-1-mediated signaling. However, in the presence of classical TLR ligands, LPC counteracts some of the TLR-mediated intracellular responses, ultimately inducing an anti-inflammatory phenotype; LPC may thus play a role in the regulation of cell immune responses and disease progression.

The influence of roncoleukin on reparative processes of bone tissue in experimental tuberculous osteitis

The effect of Roncoleukin on the recovery of the bone tissue in plastic operational defects (autobone+OsteoSet-T) on the model of experimental tuberculous osteites in 36 rabbits caused by drug resistant clinical strains of M. tuberculosis was studied. It was conducted a comparative analysis of the results of applying of Roncoleukin (12,5 mg/kg, 5 injections, one every 3 days) with anti-tuberculosis treatment in pre-and post-operative period. Efficacy was assessed in 1 and 6 months of surgical intervention on the phagocytic activity of peritoneal macrophages, X-ray study of plastics area, histological study of bone tissue sections. It was found that the most effective use of Roncoleukin appeared in the postoperative period. The analysis showed that Roncoleukin helped to accelerate the restructuring of plastic material - OsteoSet-T, reducing the prevalence of specific foci of inflammation in the bone tissue and the disappearance of alternative necrotic component; the increase of osteogenesis intensity with the new bone beams formation., as well as the activation of hematopoesis in bone marrow. The intensification of reparative processes in the bone combined with a distinct activation of phagocytosis.

In vivo, effect of herb (Withania somnifera) on immunomodulatory and antioxidative potential of milk in mice

Eighteen healthy male Swiss albino mice of specific weight (25–30g) were randomly divided into three groups of six animals each and given specific diets for a period 28 days. Group A was given normal synthetic diet (NSD) and milk; Group B: NSD and Withania somnifera (WS) extract (0.3%) and Group C: NSD supplemented with milk and WS extract (0.3%). The phagocytic activity of peritoneal macrophages and Immunoglobulin G (lgG) level in mice serum increased significantly in comparison to control group in WS-supplemented groups. The lymphocyte proliferation index did not alter significantly (P < 0.05) in supplemented groups after a period of 28 days. Group B and C showed significantly higher reduced glutathione level and significantly lowered (P < 0.05), carbonyl protein and thiobarbituric acid reactive substances in liver and red blood cells lysates as compared to control. This finding indicated that aqueous extract of WS is able to enhance immunomodulatory and antioxidative properties of milk.

Preliminary characterization and immunostimulatory activity of polysaccharides from Glossaulax didyma

In the present study, we investigated the preliminary characterization, both in vitro and in vivo immunostimulatory activity of polysaccharides from Glossaulax didyma (GPS). The results of chemical and gas chromatography analysis indicated that GPS was mainly composed of glucose with high contents of uronic acid and sulfate. For immunostimulatory activity in vitro, GPS could stimulate the proliferation of splenocytes and enhance neutral red phagocytosis, TNF-α production level and acid phosphatase activity in mouse peritoneal macrophages. For immunostimulatory activity in vivo, the administration of GPS could significantly increase the level of serum hemolysin in cyclophosphamide-treated mice. The results provided evidences that GPS possessed significant immunostimulatory activity and might be one of important active substances responsible for the immunostimulatory effect of G. didyma.

Comparative Characteristics of the Cytochemical Status of Peritoneal and Alveolar Macrophages in the Progeny of Female Rats with Experimental Liver Disease

The effects of experimental maternal chronic liver disease (induced by injection of hepatotropic toxin D(+)-galactosamine hydrochloride) on cytochemical activity of peritoneal and alveolar macrophages of the progeny were studied at different stages of postnatal development. Maternal hepatobiliary disease caused a reduction of the functional activity of macrophageal cells in the progeny, which manifested by inhibition of the lysosomal and peroxidase activities and low level of acid phosphatase.

Use of an in vitro mouse macrophage model to detect the adhesion forming potential of materials used in pelvic surgery

Even with significant precaution, pelvic surgery carries a risk of adhesion formation and its associated infertility issues. While the complete pathway is not illuminated, basic science implicates the macrophage as the main player in the inflammatory response. Activated macrophages secrete inflammatory cytokines and fibrous factors noted to contribute to adhesion formation. Therefore, cultured macrophages might prove a good model to assess materials prior to their use in pelvic surgery. The goal of the current study was to identify which suture materials caused the least peritoneal macrophages activation as an indicator of inflammatory response and predictor of adhesion formation.

Impact of Glutathione Peroxidase-1 Deficiency on Macrophage Foam Cell Formation and Proliferation: Implications for Atherogenesis

Clinical and experimental evidence suggests a protective role for the antioxidant enzyme glutathione peroxidase-1 (GPx-1) in the atherogenic process. GPx-1 deficiency accelerates atherosclerosis and increases lesion cellularity in ApoE−/− mice. However, the distribution of GPx-1 within the atherosclerotic lesion as well as the mechanisms leading to increased macrophage numbers in lesions is still unknown. Accordingly, the aims of the present study were (1) to analyze which cells express GPx-1 within atherosclerotic lesions and (2) to determine whether a lack of GPx-1 affects macrophage foam cell formation and cellular proliferation. Both in situ-hybridization and immunohistochemistry of lesions of the aortic sinus of ApoE−/− mice after 12 weeks on a Western type diet revealed that both macrophages and – even though to a less extent – smooth muscle cells contribute to GPx-1 expression within atherosclerotic lesions. In isolated mouse peritoneal macrophages differentiated for 3 days with macrophage-colony-stimulating factor (MCSF), GPx-1 deficiency increased oxidized low density-lipoprotein (oxLDL) induced foam cell formation and led to increased proliferative activity of peritoneal macrophages. The MCSF- and oxLDL-induced proliferation of peritoneal macrophages from GPx-1−/−ApoE−/− mice was mediated by the p44/42 MAPK (p44/42 mitogen-activated protein kinase), namely ERK1/2 (extracellular-signal regulated kinase 1/2), signaling pathway as demonstrated by ERK1/2 signaling pathways inhibitors, Western blots on cell lysates with primary antibodies against total and phosphorylated ERK1/2, MEK1/2 (mitogen-activated protein kinase kinase 1/2), p90RSK (p90 ribosomal s6 kinase), p38 MAPK and SAPK/JNK (stress-activated protein kinase/c-Jun N-terminal kinase), and immunohistochemistry of mice atherosclerotic lesions with antibodies against phosphorylated ERK1/2, MEK1/2 and p90RSK. Representative effects of GPx-1 deficiency on both macrophage proliferation and MAPK phosphorylation could be abolished by the GPx mimic ebselen. The present study demonstrates that GPx-1 deficiency has a significant impact on macrophage foam cell formation and proliferation via the p44/42 MAPK (ERK1/2) pathway encouraging further studies on new therapeutic strategies against atherosclerosis.

Effects of recombinant tHsp70 on immune function of tilapia peritoneal macrophages

We used recombinant tilapia Hsp70(tHsp70) from Pichia yeast to prepare non-covalent HSP70-antigen complexes with thallus and extracellular bacterial products(ECP) of Streptococcus iniae.We investigated the ef-fects of the antigen complexes on the cellular immune response of tilapia by detection of NO release,phagocytic activity,and related immune gene expression of peritoneal macrophages in vitro.tHsp70 can form complexes with the thallus and ECP of tilapia in vitro.In addition,tHsp70 alone and its complexes significantly stimulated growth and attachment of peritoneal macrophages and enhanced NO release and phagocytic activity of peritoneal macro-phages.In contrast,treatment with ECP significantly inhibited NO release and led to cell death,while treatment with tHsp70-ECP complex reduced the cell death.Moreover,tHsp70 alone or tHsp70-antigen complexes signifi-cantly increased the expression of immune related genes(IL-8,Hsp70,CXCR4,and PGRN) in tilapia peritoneal macrophages compared to antigen only and medium control groups.Our results suggest that tHsp70 has an im-munoadjuvant and immunopotentiator function,and provides experimental data for development of a tHsp70 based vaccine against tilapia streptococcal diseases.

인삼양영탕(人蔘養榮湯)이 비소세포 폐암세포(NCI-H520) 이식 마우스에서 항암 및 면역 활성에 미치는 영향

Objectives : The object of this study was to observe anticancer and related immunomodulatory effects of Insamyangyoung-tang extracts (ISYYTe) on non-small cell lung carcinoma (squamous epithelial carcinoma), NCI-H520, xenograft Balb/c nu-nu nude mice. Methods : Three different dosages of ISYYTe, 50, 100 and 200 mg/kg were orally administered once a day for 42 days from 11 days after tumor cell inoculation. Six groups, which are intact control, tumor bearing control, 5-fluorouracil (FU) 30 mg/kg, ISYYTe 50 mg/kg, ISYYTe 100 mg/kg, ISYYTe 200 mg/kg, each of 8 mice per group were used in the present study. Changes on the body weight, tumor volume and weight, lymphatic organ (spleen and popliteal lymph node), serum interferon (IFN)-<TEX>${\gamma}$</TEX> levels, splenocytes NK cell activity and peritoneal macrophage activities, splenic tumor necrosis factor (TNF)-<TEX>${\alpha}$</TEX>, interleukin (IL)-<TEX>$1{\beta}$</TEX> and IL-10 contents were observed with tumor mass and lymphatic organ histopathology to detect anticancer and immunomodulatory effects. Results : As results of ISYYTe 50, 100 and 200 mg/kg treatment, decreases in the tumor volumes and weights were detected. At histopathological observations, decreases of tumor cell volumes in tumor masses were dose-dependently decreased mediated by increases of apoptosis among tumor cells by treatment of all three different dosages of ISYYTe. As results of tumor cell inoculation, marked decreases of spleen and popliteal lymph node weights, serum IFN-<TEX>${\gamma}$</TEX>, splenic TNF-<TEX>${\alpha}$</TEX>, IL-<TEX>$1{\beta}$</TEX> and IL-10 contents and splenocytes were observed with histopathological atrophic changes of spleen and popliteal lymph nodes. Conclusions : Over 50 mg/kg of ISYYTe showed favorable anticancer effects on the NCI-H520 cell xenograft with immunomodulatory effects. Although relatively lower anticancer effects were observed in ISYYTe 200 mg/kg treated mice as compared with 5-FU 30 mg/kg treated mice, there are no meaningful favorable immunomodulatory effects were observed after 5-FU treatment in the present study.

EFFECT OF POLYPHENOLIC COMPOUNDS ISOLATED FROM CARTHAMUS TINCTORIUS AND CALENDULA OFFICINALIS L., ON FUNCTIONAL ACTIVITY OF IMMUNE CELLS UNDER CONDITIONS OF CYTOSTATIC IMMUNOSUPPRESSION

The purpose of the study – to study the effect of polyphenolic compounds extracted from the flowers of safflower oil and calendula, the functional activity of immune cells in cytotoxic immune suppression.Conventional methods determined the total number of splenocytes, relative (%) and absolute (106), the number of antibody-forming cells (AFC) in the spleen of mice by local hemolysis by Cunningham.Evaluated the effect of compounds of natural origin on the cellular immune response in the delayed-type hypersensitivity (DTH). Phagocytic activity of peritoneal macrophages was determined by the method based on the intensity of their capture ink particles. We studied the functional activity of peritoneal macrophages by NBT test (spontaneous and stimulated). Studies were conducted on male mice Category 1 (conventional linear mouse) line CBA/CaLac aged 2–2.5 months, weighing 20–22 g. After the introduction mice line CBA/CaLac of polyphenolic compounds derived from flowers of Carthamus tinctorius and flowers of Calendula officinalis L. during the 5-day course in dose 50 mg/kg was observed stimulation of the humoral immune response (total number of splenocytes, the number of antibodies in the spleen cells) and the functional activity of macrophages and Immunomodulating effect on the humoral immunity and the functional activity of macrophages after a single injection of cyclophosphamide in dose 250 mg/kg. Immunotropic activity of polyphenolic compounds is higher than that those of the reference product of tincture of Echinacea purpurea.

Extracts of Crinum latifolium inhibit the cell viability of mouse lymph oma cell line EL4 and induce activation of anti-tumour activity of macrophages in vitro

Ethnopharmacological relevanceCrinum latifolium L. (CL) leaf extracts have been traditionally used in Vietnam and are now used all over the world for the treatment of prostate cancer. However, the precise cellular mechanisms of the action of CL extracts remain unclear. Aim of the studyTo examine the effects of CL samples on the anti-tumour activity of peritoneal murine macrophages. Materials and methodsThe properties of three extracts (aqueous, flavonoid, alkaloid), one fraction (alkaloid), and one pure compound (6-hydroxycrinamidine) obtained from CL, were studied (i) for redox capacities (DPPH and bleaching beta-carotene assays), (ii) on murine peritoneal macrophages (MTT assay) and on lymphoma EL4-luc2 cells (luciferine assay) for cytotoxicity, (iii) on macrophage polarization (production of ROS and gene expression by PCR), and (iv) on the tumoricidal functions of murine peritoneal macrophages (lymphoma cytotoxicity by co-culture with syngeneic macrophages). ResultsThe total flavonoid extract with a high antioxidant activity (IC50=107.36mg/L, DPPH assay) showed an inhibitory action on cancer cells. Alkaloid extracts inhibited the proliferation of lymphoma cells either by directly acting on tumour cells or by activating of the tumoricidal functions of syngeneic macrophages. The aqueous extract induced mRNA expression of tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin 6 (IL-6) indicating differentiation of macrophages into pro-inflammatory M1 polarized macrophages. The total flavonoid, alkaloid extracts and an alkaloid fraction induced the expression of the formyl peptide receptor (FPR) on the surface of the polarized macrophages that could lead to the activation of macrophages towards the M1 phenotype. Aqueous and flavonoid extracts enhanced NADPH quinine oxido-reductase 1 (NQO1) mRNA expression in polarized macrophages which could play an important role in cancer chemoprevention. All the samples studied were non-toxic to normal living cells and the pure alkaloid tested, 6-hydroxycrinamidine, was not active in any of the models investigated. ConclusionsOur results indicate that CL extracts and alkaloid fraction (but not pure 6-hydroxycrinamidine) inhibit the proliferation of lymphoma cells in multiple pathways. Our results are in accordance with traditional usage and encourage further studies and in vivo assays.

Prior reproductive experience alters prolactin-induced macrophage responses in pregnant rats

Reproductive experience (i.e., pregnancy and lactation) induces physiological changes in mammals. A previous reproductive experience was recently shown to modulate the activity of dopaminergic hypothalamic systems while decreasing serum prolactin levels and oxidative burst activity in peritoneal macrophages. Dopamine receptor antagonists increase serum prolactin levels, and both prolactin and dopamine receptors may be involved in the modulation of macrophage activity, providing a means of communication between the nervous and immune systems. The present study evaluated the in vitro effects of prolactin and a dopamine D2 receptor antagonist on the peritoneal activity of macrophages from primigravid and multigravid female rats during the third trimester of pregnancy. Oxidative bursts and phagocytosis in peritoneal macrophages were evaluated by flow cytometry. Primigravid and multigravid Wistar rats, during the third trimester of pregnancy (i.e., days 17–21), were used. Peritoneal fluid samples from these rats were first incubated with prolactin (10 and 100nM) for different periods of time. The same procedure was repeated to evaluate the effects of domperidone (10 and 100nM) on macrophage activity. Our results showed that macrophages from multigravid rats responded more effectively to in vitro incubation with prolactin, especially with regard to the intensity and percentage of phagocytosis. Additionally, these effects were more pronounced after incubation periods of 30min or 4h. These data suggest that macrophages during a second pregnancy become more sensitive to the phagocytotic effects of prolactin.

Asymmetric dimethylarginine regulates the lipopolysaccharide-induced nitric oxide production in macrophages by suppressing the activation of NF-kappaB and iNOS expression

Two major effector systems are frequently implicated in the immune and endothelial cell alternations associated with inflammation. They include the enhanced production of reactive oxygen species and diminished bioavailability of nitric oxide (NO). Importantly, these processes can be regulated by endogenously produced methylarginines, inhibitors for NO derived from macrophages and endothelial cells. Therefore, the aim of this study was to show the potential pharmacological intervention of methylarginines (NG-methyl-L-arginine, L-NMMA; NG, NG′-dimethyl-L-arginine—symmetric dimethylarginine, SDMA; and NG, NG-dimethyl-L-arginine—asymmetric dimethylarginine, ADMA) in activation of murine peritoneal (RAW 264.7) and alveolar (MHS) macrophages with lipopolysaccharide from Gram-negative bacteria (LPS). The data presented in this study clearly declare that L-NMMA (1–50μM) and ADMA (10–50μM) significantly inhibited the LPS-induced NO production from macrophages in a concentration-dependent manner. It was demonstrated, for the first time, that the ADMA- and L-NMMA-induced down regulation of NO production was accompanied by reduced expression of mRNA and protein for inducible NO synthase as well as decreased activation of nuclear factor-κB. Importantly, we found a negative correlation between the ADMA-dependent reduction of NO production and ADMA-increased superoxide formation, which indicates that ADMA can negatively affect the balance in LPS-induced macrophage-derived production of reactive mediators. The only effect of SDMA was observed for LPS-triggered superoxide production, which was significantly decreased in its highest concentration (50μM). In summary, L-NMMA and ADMA can mediate their effects on macrophage activation via regulation of intracellular signaling pathways, which can affect critical functions in activated macrophages.

Altered Lymphocyte Proliferation and Innate Immune Function in Scrapie 139A- and ME7-Infected Mice

Lymphoid organs play an important role in prion disease development and progression. While the role of lymphoid organs and changes in immune-related genes have been extensively investigated in scrapie-infected animals, innate immunity has not. Previous studies examined lymphocyte function in scrapie-infected C3H/HeJ mice, which exhibit defects in lipopolysaccharide (LPS) response now known to result from a mutation in Toll-like receptor (TLR) 4. We examined immune function in scrapie-infected CD1 mice, which are LPS responders. Lymphocyte proliferation from CD1 mice infected with either 139A or ME7 scrapie was measured in response to concanavalin (Con) A or LPS at 1 and 3 months after infection. Following LPS exposure, mice infected 3 months with ME7, but not 139A, demonstrated significantly decreased lymphocyte proliferation compared to controls. After Con A exposure, lymphocyte proliferation in scrapie-infected mice did not differ from controls. Gender-specific comparison of lymphocyte proliferation showed significant decreases in mitogenic responses in females infected 3 months with either 139A or ME7, compared to controls. Males infected for 3 months with ME7, but not 139A, showed significantly decreased proliferation after lymphocyte exposure to LPS, but not Con A. Neither gender showed changes in lymphocyte proliferation after 1 month of scrapie infection. Innate immune activation of peritoneal macrophages was determined via production of nitric oxide (NO), IL-6, and TNF-α after exposure to TLR ligands. TNF-α and IL-6 production were reduced in macrophages from females infected with either scrapie strain for 3 months, while NO production after TLR agonist plus IFN-γ exposure was decreased in both females and males infected for 3 months with 139A, compared to ME7. These data demonstrated altered innate immunity, suggesting hormonal and/or other gender-specific regulation may contribute to gender differences in some immune functions. Our data demonstrate lymphocyte proliferation and innate immune functioning in scrapie-infected mice deteriorate with disease progression.

Fat Necrosis Generates Proinflammatory Halogenated Lipids During Acute Pancreatitis

To evaluate the generation of halogenated fatty acids in the areas of fat necrosis during acute pancreatitis and to evaluate the effects of these molecules on the ensuing inflammatory process. Lipid mediators derived from adipose tissue have been implicated in the progression of acute pancreatitis, although their precise role remains unknown. Acute pancreatitis was induced in rats by intraductal infusion of 3.5% sodium taurocholate. Fatty acid chlorohydrins (FA-Cl) were measured in adipose tissue, ascitic fluid, and plasma by mass spectrometry. Chlorohydrins were also instilled in the rats' peritoneal cavity, and their effects on peritoneal macrophages activation and in systemic inflammation were evaluated. Finally, they have also been measured in plasma from human patients with acute pancreatitis. Induced acute pancreatitis results in a substantial release not only of free fatty acids but also of the chlorohydrins of both oleic and linoleic acids from adipose tissue. In plasma, only the chlorohydrin of oleic acid was detected. Administration of 250-μM lipid chlorohydrins, which is the concentration found in ascitic fluid, induces the expression of TNFα and interleukin-1β in peritoneal macrophages and increases the systemic inflammatory response in pancreatitis. Finally, increased concentrations of oleic acid chlorohydrin have been found in plasma of human patients with pancreatitis. During acute pancreatitis, adipose tissue release FA-Cl, which exacerbate the systemic inflammatory response.

Activin A inhibits activities of lipopolysaccharide-activated macrophages via TLR4, not of TLR2

Activin A, a member of TGF-β superfamily, is involved in either pro-inflammatory or anti-inflammatory responses. Our previous studies have reported that lipopolysaccharide (LPS) can simulate activin A secretion from macrophage, and activin A can induce rest macrophage activation in mice, but inhibit the activities of the activated macrophages. However, the relationship of activin and LPS actions and their mechanism are not well characterized. In the present study, the results showed that both activin A and LPS promoted the phagocytic activities of mouse peritoneal macrophages in vivo and in vitro, but activin A inhibited the phagocytosis of LPS-activated macrophages. Simultaneously, the results revealed that activin A inhibited the Toll-like receptor 4 (TLR4) expression on LPS-activated mouse peritoneal macrophages in vivo and in vitro, whereas there was no obvious change of TLR2 expression. Moreover, the results showed that activin A obviously reduced the TLR4 mRNA and protein expressions in LPS-activated macrophage cell line RAW264.7 cells, and the inhibitory effect of activin A on the TLR4 expression was significantly attenuated in Smad3 knock-down RAW264.7 cells. Interestingly, LPS promoted the expression of activin type IIA receptor (ActRIIA) on mouse peritoneal macrophages in vivo, and also up-regulated ActRIIA and activin signal molecules Smad2, 3 mRNA expressions. These data suggest that activin A inhibits LPS action on macrophages in vivo via suppressing TLR4 expression, and LPS further augments the negative feedback action of activin A via up-regulating activin signaling transduction.

Acute pancreatitis in obese patients

Introduction: Obesity increases severity of acute pancreatitis by unclear mechanisms. Recent clinical studies demonstrate that all major complications are more common and more severe in patients who are obese. Patients with higher body mass index have increased risk of local and systemic complications of acute pancreatitis and patients with android fat distribution and higher waist circumference are at greater risk for developing the severe acute pancreatitis (SAP). Aims:We investigated the relationship between visceral adipose tissue and acute pancreatitis. Patients &methods:We examined 13 patients with acute pancreatitis. In 6 patients BMI was more 30. Computed tomography was performed in all patients. Results: Pancreatitis induces the activation of peritoneal macrophages and a strong inflammatory response in mesenteric sites of adipose tissue. In obese humans, we found that an increase in the volume of intrapancreatic adipocytes was associated with more extensive pancreatic necrosis during acute pancreatitis and that acute pancreatitis was associated with multisystem organ failure in obese individuals. Patients with SAP had higher BMIs and more intrapancreatic fat than those with mild AP. Conclusion: The results confirm the involvement of adipose tissue on the progression of systemic inflammatory response during acute pancreatitis. However, there is a considerable diversity in different adipose tissue sites. These differences need to be taken into account in order to understand the progression from local pancreatic damage to systemic inflammation during acute pancreatitis. Therapeutic approaches that target unsaturated fatty acid-mediated lipotoxicity may reduce adverse outcomes in obese patients with critical illnesses such as severe acute pancreatitis.