The Mesentery's Pivotal Role in the Brain-Gut-Liver Axis.

Background: Prior to 2012, the mesentery was perceived as a fragmented structure, lacking distinct functional and anatomical characteristics, and was merely considered part of other digestive organs. Dr. J. Calvin Coffey's in 2012 in his study redefined the mesentery as a distinct organ with a clearly defined anatomical and histological structure, although its specific function remains under investigation. The continuous structure and unique tissue properties of the mesentery classify it as the 78th independent organ in the human body. Insights into mesenteric adipose tissue have enhanced our understanding of normal metabolic processes and disease etiology, impacting health significantly. Experimental and clinical research highlights the vital roles of visceral adipose tissue, influencing neighboring organ function. The interaction within the brain-gut-liver axis is illuminated by the newfound functions of mesenteric adipose tissue, emphasizing its independent organ status. Objective: This study aims to evaluate the latest findings on the structure and function of the mesentery, focusing on visceral-mesenteric adipose tissue, and assess its role as a new organ in the brain-gut-liver axis. Methods: A comprehensive analysis of clinical and experimental studies on the mesentery's structure and function was conducted, focusing on recent discoveries regarding mesenteric adipose tissue and its role in the brain-gut-liver axis. Results and Discussion: Recent research has revealed the mesentery's unique functions, particularly in mesenteric adipose tissue. Mesenteric adipose tissue plays a crucial role in metabolic functions and influences disease onset. It acts as a vital link in the brain-gut-liver axis, directly influencing hepatic metabolism and disorders such as metabolic syndrome. Conclusion: Scientific evidence confirms the mesentery's anatomical and functional specificities, solidifying its status as the 78th independent organ in the human body. It serves as a crucial link in the brain-mesentery-small intestine-liver axis, impacting health and disease. Ongoing research holds promise for advancing our understanding of pathophysiological mechanisms and treatment approaches for metabolic syndrome and other chronic diseases.

The implication of mesenteric functions and the biological effects of nanomaterials on the mesentery.

A growing number of nanomaterials are being broadly used in food-related fields as well as therapeutics. Oral exposure to these widespread nanomaterials is inevitable, with the intestine being a major target organ. Upon encountering the intestine, these nanoparticles can cross the intestinal barrier, either bypassing cells or via endocytosis pathways to enter the adjacent mesentery. The intricate structure of the mesentery and its entanglement with the abdominal digestive organs determine the final fate of nanomaterials in the human body. Importantly, mesentery-governed dynamic processes determine the distribution and subsequent biological effects of nanomaterials that cross the intestine, thus there is a need to understand how nanomaterials interact with the mesentery. This review presents the recent progress in understanding the mesenteric structure and function and highlights the importance of the mesentery in health and disease, with a focus on providing new insights and research directions around the biological effects of nanomaterials on the mesentery. A thorough comprehension of the interactions between nanomaterials and the mesentery will facilitate the design of safer nanomaterial-containing products and the development of more effective nanomedicines to combat intestinal disorders.

Desmoid-type fibromatosis of the mesentery: a clinicopatho-logical and genetic analysis of 9 cases. / è‚ ç³»è†œéŸ§å¸¦æ ·çº¤ç»´ç˜¤ç— æ‚£è€ ä¸´åºŠç— ç†å­¦åˆ†æž.

Nine cases of mesenteric desmoid-type fibromatosis were diagnosed and treated in Taizhou Hospital, Wenzhou Medical University between January 2010 and May 2022, including 2 females and 7 males, aged 16 to 59 years. The lesions were in the mesentery of small intestine with 7 cases, ileocecal junction with 1 cases and transverse colon with 1 case. The tumors had an unclear boundary and no envelope, the section was solid, gray and tough. The mean maximum diameter was (10.7±8.5) cm (range 3.5-33.0 cm). Microscopically, fusiform fibroblasts and myofibroblasts were parallel, bunched or staggered, buried in a large amount of extracellular collagen. The cell morphology was relatively consistent, without obvious atypia, and mitosis was rare. Immunohistochemistry showed that the tumor cells were positive for vimentin (9/9), ß-catenin (9/9), while smooth muscle actin (5/9) stains were focally positive. Ki-67 proliferation index was 1%-10%. Cytokeratin Pan, S-100, STAT6, CD117, DOG1, CD34, desmin and anaplastic lymphoma kinase stains were negative. Genetic analysis showed that there were 7 cases of c.121G>A(p.Thr41Ala) mutation of CTNNB1 gene, 1 case of c.121G>A(p.Thr41Ala) and 1 case of c.134C>T(p.Ser45Phe) double mutation, and 1 case of wild type. Tumors were surgically resected in all 9 cases. Eight cases had no recurrence or metastasis, 1 case had recurrence 6 months later, and no recurrence or metastasis after additional surgical resection.

A Rare Cause of Abdominal Pain: IgG4-Related Sclerosing Mesenteritis.

A 67-year-old man with previous cardiovascular disease was referred to our consultation due to a 5-month history of recurrent epigastric pain. Esophagogastroduodenoscopy and full blood workup presented no alterations. CT scan showed an irregularly shaped mass at the root of the mesentery, measuring 40x25x47mm, with spiculated contours and retractile behaviour (a). Simultaneous densification of the adjacent fat and infracentimetric ganglionic formations scattered throughout the mesentery were shown. Surgical biopsy revealed extensive storiform fibrosclerosis, with the presence of interstitial lymphoplasmocytic infiltrate and obliterative phlebitis (b); the plasma cells had mostly IgG expression, with IgG4:IgG ratio >40% (c), accounting for more than 30- 40 IgG4 plasma cells per field. The serum IgG4 level was 137mg/dL. A diagnosis of IgG4-related sclerosing mesenteritis was made, without other organ involvement. Prednisolone (0.6mg/kg/d) improved partially the abdominal pain, so steroid sparing strategy with off-label rituximab was associated. Due to its low prevalence, the understanding of this entity is scarce, and its diagnosis is challenging. Unlike other manifestations of IgG4-related disease, the intra-abdominal disease is identified in later stages, due to unspecific symptoms. This case aims to raise awareness about this condition as a differential diagnosis of abdominal pain.

[Inducible co-stimulatory molecules participate in mesenteric vascular endothelial-mesenchymal transition and sclerosis of mesenteric vessels in spontaneously hypertensive rats].

OBJECTIVE: To investigate the correlation of inducible co-stimulatory molecules (ICOS) with mesenteric vascular endothelial- mesenchymal transition (EndMT) and sclerosis in spontaneously hypertensive rats (SHR). METHODS: Twenty 4-week-old WKY rats and 20 SHRs of the same strain were both randomly divided into 4 groups for observation at 4, 6, 10 and 30 weeks of age. ICOS expression frequency in rat spleen CD4+T cells was analyzed using flow cytometry, and the expressions of ICOS, VE-cad, α-SMA and Col3 mRNA in rat mesentery were detected by RT-PCR. The distributions of ICOS, IL-17A and TGF-ß in rat mesentery were detected by immunohistochemistry. The levels of IL-17A and TGF-ß in rat plasma were measured using ELISA. The morphological changes of rat mesenteric vessels were observed with Masson staining. Spearman or Pearson correlation analyses were used to evaluate the correlation between ICOS expression and the expressions of the markers of vascular EndMT and sclerosis. RESULTS: Compared with the control WKY rats, the SHRs began to show significantly increased systolic blood pressure and ICOS expression frequency on CD4+T cells at 6 weeks of age (P < 0.05). In the SHRs, the mRNA and protein expressions of ICOS, α-SMA, Col3, IL-17A and TGF-ß in the mesentery were significantly higher than those in control group (P < 0.05), while the mRNA and protein expressions of VE-cad started to reduce significantly at 10 weeks of age (P < 0.05). The plasma levels of IL-17A and TGF-ß were significantly increased in SHRs since 6 weeks of age (P < 0.05) with progressive worsening of mesenteric vascular sclerosis (P < 0.05). ICOS mRNA and protein expression levels in the mesenteric tissues of SHRs began to show positive correlations with α-SMA and Col3 expression levels and the severity of vascular sclerosis at 6 weeks of age (P < 0.05) and a negative correlation with VE-cad expression level at 10 weeks (P < 0.05). CONCLUSION: ICOS play an important pathogenic role in EndMT and sclerosis of mesenteric vessels in essential hypertension by mediating related immune responses.

Creeping fat formation and interaction with intestinal disease in Crohn's disease.

Creeping fat (CrF), also known as fat wrapping, is a significant disease characteristic of Crohn's disease (CD). The transmural inflammation impairs intestinal integrity and facilitates bacteria translocation, aggravating immune response. CrF is a rich source of pro-inflammatory and pro-fibrotic cytokines with complex immune microenvironment. The inflamed and stricturing intestine is often wrapped by CrF, and CrF is associated with greater severity of CD. The large amount of innate and adaptive immune cells as well as adipocytes in CrF promote fibrosis in the affected intestine by secreting large amount of pro-fibrotic cytokines, adipokines, growth factors and fatty acids. CrF is a potential therapeutic target for CD treatment and a promising bio-marker for predicting response to drug therapy. This review aims to summarize and update the clinical manifestation and application of CrF and the underlying molecular mechanism involved in the pathogenesis of intestinal inflammation and fibrosis in CD.

Obesity-associated mesenteric lymph leakage impairs the trafficking of lipids, lipophilic drugs and antigens from the intestine to mesenteric lymph nodes.

Dietary lipids, highly lipophilic drugs, antigens and immune cells are transported from the intestine to the mesenteric lymph nodes (MLNs) via mesenteric lymphatic vessels. Recently our lab reported that the mesenteric lymphatic vessels become highly branched and leak lymph to the surrounding mesenteric adipose tissue (MAT) in mice and humans with obesity, promoting insulin resistance. This study aimed to investigate the impact of obesity-associated mesenteric lymph leakage on the trafficking of a dietary lipid (oleic acid), lipophilic drug (cyclosporin A) and antigen (ovalbumin) from the intestine to MLNs. C57BL/6J mice were fed a control fat diet (CFD), or a high fat diet (HFD) for up to 35 weeks leading to obesity and impaired glucose tolerance. 14C-oleic acid, 3H-cyclosporin or Cy5.5-ovalbumin were administered orally, and blood plasma and tissues collected to measure radioactivity or fluorescence levels. The accumulation of 14C-oleic acid, 3H-cyclosporin and Cy5.5-ovalbumin in MAT was significantly increased in HFD compared to CFD fed mice, whereas in the MLNs there was less accumulation (3H-cyclosporin and Cy5.5-ovalbumin) or no significant difference (for 14C-oleic acid). The mass ratio of these molecules in MLNs compared to MAT was thus significantly decreased. Obesity-associated mesentery lymph leakage appears to divert dietary lipids, lipophilic drugs and antigens away from their normal lymphatic trafficking pathways from the intestine to MLNs and instead results in leakage into MAT. This is likely to contribute to known detrimental changes to lipid metabolism, immunotherapy and mucosal immunity in obesity.

Effect of Crohn's disease mesenteric mesenchymal stem cells and their extracellular vesicles on T-cell immunosuppressive capacity.

Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal intestinal tract and has characteristic hypertrophic adipose changes observed in the mesentery. To better understand the role of the mesentery in the pathophysiology of Crohn's disease (CD), we evaluated the immunomodulatory potential of mesenchymal stem cells (MSCs) and their secreted extracellular vesicles (EVs) derived from Crohn's patients. MSCs and EVs were isolated from the mesentery and subcutaneous tissues of CD patients and healthy individuals subcutaneous tissues, and were analysed for differentiation, cytokine expression, self-renewal and proliferation. The varying capacity of these tissue-derived MSCs and EVs to attenuate T-cell activation was measured in in vitro and an in vivo murine model. RNA sequencing of inflamed Crohn's disease mesentery tissue revealed an enrichment of T-cell activation compared to non-inflamed subcutaneous tissue. MSCs and MSC-derived EVs isolated from Crohn's mesentery lose their ability to attenuate DSS-induced colitis compared to subcutaneous tissue-derived cell or EV therapy. We found that treatment with subcutaneous isolated MSCs and their EV product compared to Crohn's mesentery MSCs or EVs, the inhibition of T-cell proliferation and IFN-γ, IL-17a production increased, suggesting a non-inflamed microenvironment allows for T-cell inhibition by MSCs/EVs. Our results demonstrate that Crohn's patient-derived diseased mesentery tissue MSCs lose their immunosuppressive capacity in the treatment of colitis by distinct regulation of pathogenic T-cell responses and/or T-cell infiltration into the colon.

Age-Associated B Cell Features of the Murine High-Grade B Cell Lymphoma Bc.DLFL1 and Its Extranodal Expansion in Abdominal Adipose Tissues.

Diffuse large B cell lymphoma comprises a heterogeneous group of B cell-derived tumors, with different degrees of aggressiveness, as defined by their cellular origin and tissue microenvironment. Using the spontaneous Bc.DLFL1 lymphoma originating from a BALB/c mouse as a diffuse large B cell lymphoma model, in this study we demonstrate that the lymphoma cells display surface phenotype, IgH V-region somatic mutations, transcription factor characteristics and in vivo location to splenic extrafollicular regions of age-associated B cells (ABCs), corresponding to T-bet+ and Blimp-1+/CD138- plasmablasts derivation. The expansion of lymphoma cells within lymphoid tissues took place in a close arrangement with CD11c+ dendritic cells, whereas the extranodal infiltration occurred selectively in the mesentery and omentum containing resident gp38/podoplanin+ fibroblastic reticular cells. Antagonizing BAFF-R activity by mBR3-Fc soluble receptor fusion protein led to a significant delay of disease progression. The extranodal expansion of Bc.DLFL1 lymphoma within the omental and mesenteric adipose tissues was coupled with a significant change of the tissue cytokine landscape, including both shared alterations and tissue-specific variations. Our findings indicate that while Bc.DLFL1 cells of ABC origin retain the positioning pattern within lymphoid tissues of their physiological counterpart, they also expand in non-lymphoid tissues in a BAFF-dependent manner, where they may alter the adipose tissue microenvironment to support their extranodal growth.

Pygopus2 ameliorates mesenteric adipocyte poor differentiation to alleviate Crohn's disease -like colitis via the Axin2/GSK3ß pathway.

OBJECTIVES: Crohn's disease (CD) mesenteric adipose tissue (MAT) inflammation affects enteritis through the interaction between the mesentery and intestine, and we previously found that poorly differentiated mesenteric adipocytes were related to its inflammatory features. Pygopus2 (Pygo2) is a key negative regulator of adipocyte differentiation. We aimed to determine whether Pygo2 participates in CD mesenteric lesions and whether Pygo2 knockdown would be beneficial in a CD model (Il-10-/- mice). METHODS: Pygo2 expression in MAT from control and CD patients and Il-10-/- mice was measured by immunohistochemistry. Lentiviral transfection was used to regulate Pygo2 expression in Il-10-/- mice, and the effects on mesenteric adipocyte differentiation, inflammation, and dysfunction during spontaneous colitis, as well as the possible mechanism, were investigated. RESULTS: Pygo2 expression was increased in MAT from CD patients and Il-10-/- mice, and its expression correlated with poor adipocyte differentiation and inflammation. Pygo2 knockdown significantly ameliorated colitis in Il-10-/- mice. Moreover, the downregulation of Pygo2 gene expression could promote adipocyte differentiation and inhibit adipocyte inflammation in vivo and in vitro, and the effects were at least partly mediated by the Axis inhibition protein 2 (Axin2)/glycogen synthase kinase 3 beta (GSK3ß) pathway. CONCLUSIONS: The increase in Pygo2 may be related to mesenteric adipocyte poor differentiation and inflammatory features of CD, and Pygo2 inhibition could alleviate CD-like colitis by improving mesenteric lesions by regulating the Axin2/GSK3ß pathway.

Off-Target Effect of Lovastatin Disrupts Dietary Lipid Uptake and Dissemination through Pro-Drug Inhibition of the Mesenteric Lymphatic Smooth Muscle Cell Contractile Apparatus.

Previously published, off-target effects of statins on skeletal smooth muscle function have linked structural characteristics within this drug class to myopathic effects. However, the effect of these drugs on lymphatic vascular smooth muscle cell function, and by proxy dietary cholesterol uptake, by the intestinal lymphatic network has not been investigated. Several of the most widely prescribed statins (Atorvastatin, Pravastatin, Lovastatin, and Simvastatin) were tested for their in-situ effects on smooth muscle contractility in rat mesenteric collecting lymphatic vessels. Lovastatin and Simvastatin had a concentration-dependent effect of initially increasing vessel contraction frequency before flatlining the vessel, a phenomenon which was found to be a lactone-ring dependent phenomenon and could be ameliorated through use of Lovastatin- or Simvastatin-hydroxyacid (HA). Simvastatin treatment further resulted in mitochondrial depolymerization within primary-isolated rat lymphatic smooth muscle cells (LMCs) while Lovastatin was found to be acting in a mitochondrial-independent manner, increasing the function of RhoKinase. Lovastatin's effect on RhoKinase was investigated through pharmacological testing and in vitro analysis of increased MLC and MYPT1 phosphorylation within primary isolated LMCs. Finally, acute in vivo treatment of rats with Lovastatin, but not Lovastatin-HA, resulted in a significantly decreased dietary lipid absorption in vivo through induced disfunction of mesenteric lymph uptake and trafficking.

Whole blood resuscitation restores intestinal perfusion and influences gut microbiome diversity.

OBJECTIVE: Gut dysbiosis, an imbalance in the gut microbiome, occurs after trauma, which may be ameliorated with transfusion. We hypothesized that gut hypoperfusion following trauma causes dysbiosis and that whole blood (WB) resuscitation mitigates these effects. METHODS: Anesthetized rats underwent sham (S; laparotomy only, n = 6); multiple injuries (T; laparotomy, liver and skeletal muscle crush injuries, and femur fracture, n = 5); multiple injuries and 40% hemorrhage (H; n = 7); and multiple injuries, hemorrhage, and WB resuscitation (R; n = 7), which was given as 20% estimated blood volume from donor rats 1 hour posttrauma. Baseline cecal mesenteric tissue oxygen (O2) concentration was measured following laparotomy and at 1 hour and 2 hours posttrauma. Fecal samples were collected preinjury and at euthanasia (2 hours). 16S rRNA sequencing was performed on purified DNA, and diversity and phylogeny were analyzed with QIIME (Knight Lab, La Jolla, CA; Caporaso Lab, Flagstaff, AZ) using the Greengenes 16S rRNA database (operational taxonomic units; 97% similarity). α and ß diversities were estimated using observed species metrics. Permutational analysis of variance was performed for overall significance. RESULTS: In H rats, an average decline of 36% ± 3.6% was seen in the mesenteric O2 concentration at 1 hour without improvement by 2 hours postinjury, which was reversed following resuscitation at 2 hours postinjury (4.1% ± 3.1% difference from baseline). There was no change in tissue O2 concentration in the S or T rats. ß Diversity differed among groups for all measured indices except Bray-Curtis, with the spatial median of the S and R rats more similar compared with S and H rats (p < 0.05). While there was no difference in α diversity found among the groups, indices were significantly correlated with mesenteric O2 concentration. Members of the family Enterobacteriaceae were significantly enriched in only 2 hours. CONCLUSION: Mesenteric perfusion after trauma and hemorrhage is restored with WB resuscitation, which influences ß diversity of the gut microbiome. Whole blood resuscitation may also mitigate the effects of hemorrhage on intestinal dysbiosis, thereby influencing outcomes.

Analysis of Lymphatic Vessel Formation by Whole-Mount Immunofluorescence Staining.

Pathological alterations of lymphatic structure and function interfere with lymph transport, resulting in a wide range of clinical disorders that include edema, tissue inflammation, and metabolic syndromes. Mesentery contains abundant lymphatic vessels and plays an important role in transporting absorbed lipid from the intestine. In this manuscript, we describe a whole-mount staining method on isolated mouse mesentery with VEGFR3, Prox1, and Lyve1 antibodies to visualize the morphology of lymphatic vessels.

Madecassoside Inhibits Body Weight Gain via Modulating SIRT1-AMPK Signaling Pathway and Activating Genes Related to Thermogenesis.

Background: Pre-clinical research studies have shown that Madecassoside (MA) has favorable therapeutic effects on arthritis, acne, vitiligo and other diseases. However, the effects of MA on obesity have not yet been studied. This study mainly aimed to investigate the effects of MA in protecting against obesity and its underlying mechanism in reducing obesity. Methods: Obese diabetic KKay/TaJcl mice model was adopted to the study. The body weight of all animals was recorded daily, and the blood glucose, blood lipid, and serum aminotransferase levels were examined, respectively. The expression of P-AMPK, SIRT1, P-LKB1, P-ACC, and P-HSL in abdominal fat, mesenteric fat, and epididymal fat was measured by western blotting, and the levels of PPARα, CPT1a, PGC-1α, UCP-1, Cidea, Cox7a1, and Cox8b were examined by real-time quantitative PCR (RT-qPCR). Results: The results revealed that the body weight of the mice in MA group was significantly reduced, and the body mass index (BMI) showed significant difference between the two groups after 8 weeks of MA treatment. Further research revealed that it affected the mesenteric fat and epididymis fat by activating SIRT1/AMPK signaling pathway, and then promoted fatty acid oxidation of epididymal fat (PPARα ↑, CPT1a↑, and PGC-1α↑). Last but not the least, it also promoted the expression of UCP-1 and stimulated thermoregulatory genes (Cidea, Cox7a1, and Cox8b) in brown fat and mesenteric fat. Conclusions: Taken together, these findings suggest that MA can inhibit the weight gain in obese diabetic mice, and reduce triglyceride levels, inhibit lipogenesis of mesenteric fat, promote epididymal fat lipolysis and fatty acid oxidation. Furthermore, MA treatment might promote mesenteric fat browning and activate mitochondrial function in brown fat as well as mesenteric fat.

Increased proinflammatory cytokines in mesenteric fat in major surgery and Crohn's disease.

BACKGROUND: Proinflammatory cytokines play an important role in abdominal surgery and are often associated with the development of postoperative ileus, especially in Crohn's disease. The aim of this study was to investigate proinflammatory cytokine levels in mesenteric fat in Crohn's disease and patients without Crohn's disease. METHODS: Human mesenteric tissue specimen were divided into 3 patient groups (n = 10 each): minor surgery (laparoscopic cholecystectomy), major surgery (colectomy) in patients without Crohn's disease, and major surgery (colectomy) in patients with Crohn's disease. Levels of interleukin 6, interleukin 1-ß, and tumor necrosis factor α were determined by cytometric bead array, enzyme-linked immunosorbent assay and reverse transcription polymerase chain reaction. The Kruskal-Wallis and the Mann-Whitney U test were used to compare continuous variables. For categorical variables, the χ2 test or Fisher exact test was used. RESULTS: In minor surgery, cytokines levels of interleukin 6, interleukin 1-ß and Tumor necrosis factor α were low (ie, interleukin 6: 1 pg/mL [0-36], interleukin 1-ß: 0 fg/mL [0-18], tumor necrosis factor α: 157 fg/mL [91-237]) compared with major surgery in patients with and without Crohn's disease. Cytokines were significantly higher in major surgery (ie, interleukin 6: 147 pg/mL [29-347], interleukin 1-ß: 660 fg/mL [0-2580], tumor necrosis factor α: 532 fg/mL [289-1647]; P = .02 and major surgery with CD (cytometric bead array: interleukin 6: 94 pg/mL [24-627], interleukin 1-ß: 708 fg/mL [0-1664], tumor necrosis factor α: 733 fg/mL [209-1,354]; P < .05). Cytokine levels in major surgery with Crohn's disease showed a further increase of interleukin 6 in polymerase chain reaction in comparison to major surgery in patients without Crohn's disease (1.2 vs 4, P = .04). CONCLUSION: Proinflammatory cytokines are increased in the mesenteric fat in major operations compared to minor operations, which indicates local mesenteric inflammation. In Crohn's disease, levels of proinflammatory cytokines are even higher, which may put the patients at risk for postoperative ileus.

Chylomicrons-Simulating Sustained Drug Release in Mesenteric Lymphatics for the Treatment of Crohn's-Like Colitis.

BACKGROUND AND AIMS: Alteration to both the structures and functions of mesenteric lymphatic vessels is a typical hallmark of Crohn's disease [CD]. Dysfunctional lymphatics was observed in patients with both CD and experimental colitis, suggesting mesenteric lymphatics could be potential therapeutic targets. This study aimed to develop a nano-delivery system which can enhance drug delivery in mesenteric lymphatic tissue [MLT] and evaluate the therapeutic effects in Crohn's colitis. METHODS: We designed a mesoporous silica nanoparticle [MSN] conjugated with long-chain fatty acid [LMSN] and covered with enteric coating [ELMSN] which can be specifically transported via the mesenteric lymphatic system. The therapeutic efficacy of laquinimod-loaded nanoparticles [LAQ@ELMSN] was evaluated in the well-established interleukin [IL]-10-/- spontaneous experimental colitis. RESULTS: ELMSNs induced sustainable drug release that markedly increased drug concentration in MLT. In experimental colitis, the lymphatics-targeting drug delivery system suppressed lymphangitis and promoted lymphatic drainage. The downregulation of pro-inflammatory cytokines and the downstream NF-κB-related proteins efficiently inhibited lymphangiogenesis and restored tight junctions of mesenteric lymphatic vessels [MLVs]. LAQ@ELMSN showed a superior therapeutic effect in ameliorating intestinal inflammation compared with free drug administration. Alteration of gut microbiota and metabolites in experimental colitis was also reversed by LAQ@ELMSN. CONCLUSION: Our study demonstrates a convenient, orally administered drug delivery system which enhances drug release in MLT. The results confirm the contribution of the mesenteric lymphatic system to the pathogenesis of gut inflammation and shed light on the application of lymphatics-targeting drug delivery therapy as a potential therapeutic strategy for CD treatment.

Inducing a stressed phenotype in healthy recipient mice by adoptively transferring CD4+ lymphocytes from mice undergoing chronic psychosocial stress.

Although chronic stress is an acknowledged risk factor for the development of somatic and affective disorders, the cellular and molecular mechanisms underlying stress-induced pathologies are not fully understood. Interestingly, rodent studies involving immune cell transfer suggest that CD4+ T cells might be at least in part involved in reactivation of a chemically-induced colitis by stress. However, until now evidence is lacking that these immune cell types are indeed involved in the development of a "stressed phenotype". The aim of the present study was, therefore, to assess the effects of adoptively transferring total mesenteric lymph node cells (mesLNCs) and CD4+ mesLNCs isolated from chronically-stressed mice into healthy recipient mice on various physiological, immunological and behavioral parameters. To induce chronic psychosocial stress in donor mice we employed the chronic subordinate colony housing (CSC) paradigm. Our data indicate that transfer of total or CD4+ mesLNCs from CSC mice, compared with respective cells from single-housed control (SHC) mice, promoted splenomegaly and interferon (IFN)-γ secretion from in vitro anti-CD3-stimulated mesLNCs in naïve recipient mice. This effect was independent of recipient mice additionally being administered with dextran sulfate sodium (DSS) or not. Transfer of CD4+ mesLNCs additionally increased adrenal weight and secretion of IL-6 from in vitro anti-CD3 stimulated mesLNCs in recipients administered with DSS. Importantly, transfer of neither cell type from CSC vs. SHC donor mice affected anxiety-related behavior of recipient mice in the light-dark box. Taken together, our data demonstrate that typical physiological and immunological, but not behavioral, effects of chronic stress can be induced in naïve recipient mice by adoptively transferring mesLNCs, in particular CD4+ mesLNCs, from chronically stressed donor mice.

The role of mesenteric lymph exosomal lipid mediators following intestinal ischemia-reperfusion injury on activation of inflammation.

BACKGROUND: Intestinal ischemia caused by hemorrhagic shock is known to induce systemic inflammatory responses. Previous studies have shown that mesenteric lymph (ML) plays a crucial role in gut-mediated inflammation. Lipid mediators, such as lysophosphatidylcholines (LPCs), which contain polyunsaturated fatty acids (PUFAs), are present in the postshock ML. Exosomes are also present in the ML and act as transcellular carriers of lipids; however, their role in postshock systemic inflammation has not been revealed. Here, we aimed to identify changes in lipid mediators in ML exosomes after intestinal ischemia. METHODS: Male Sprague-Dawley rats underwent laparotomy, followed by ML duct cannulation. Animals were subjected to 60 minutes of intestinal ischemia by superior mesenteric artery clamping, followed by 120 minutes of reperfusion. Mesenteric lymph was obtained before and after intestinal ischemia, and exosomes were isolated from ML by ultracentrifugation. The biological activity of ML exosomes was determined using the monocyte nuclear factor κB (NF-κB) activation assay. Lipids of ML exosomes were extracted and quantified by liquid chromatography/electrospray ionization mass spectrometry. RESULTS: Mesenteric lymph exosome-induced NF-κB activation significantly increased after intestinal ischemia, and lipid analysis revealed a significant increase in the concentration of PUFA-containing LPCs. In addition, PUFA-containing LPCs also induced NF-κB activation. CONCLUSION: Our results suggest that biologically active lipid mediators in ML exosomes may be involved in the inflammatory response after intestinal ischemia.

Alkaline Phosphatase Activity Is a Key Determinant of Vascular Responsiveness to Norepinephrine.

Here, we tested the hypothesis that TNAP (tissue nonspecific alkaline phosphatase) modulates vascular responsiveness to norepinephrine. In the isolated, Tyrode's-perfused rat mesentery, 50 µmol/L of L-p-bromotetramisole (L-p-BT; selective TNAP inhibitor, Ki=56 µmol/L) significantly reduced TNAP activity and caused a significant 9.0-fold rightward-shift in the norepinephrine concentration versus vasoconstriction relationship. At 100 µmol/L, L-p-BT further reduced mesenteric TNAP activity and caused an additional significant right-shift of the norepinephrine concentration versus vasoconstriction relationship. A higher concentration (200 µmol/L) of L-p-BT had no further effect on either mesenteric TNAP activity or norepinephrine-induced vasoconstriction. L-p-BT did not alter vascular responses to vasopressin, thus ruling-out nonspecific suppression of vascular reactivity. Since in the rat mesenteric vasculature α1-adrenoceptors mediate norepinephrine-induced vasoconstriction, these finding indicate that TNAP inhibition selectively interferes with α1-adrenoceptor signaling. Additional experiments showed that the effects of TNAP inhibition on norepinephrine-induced vasoconstriction were not mediated by accumulation of pyrophosphate or ATP (TNAP substrates) nor by reduced adenosine levels (TNAP product). TNAP inhibition significantly reduced the Hillslope of the norepinephrine concentration versus vasoconstriction relationship from 1.8±0.2 (consistent with positive cooperativity of α1-adrenoceptor signaling) to 1.0±0.1 (no cooperativity). Selective activation of A1-adenosine receptors, which are known to participate in coincident signaling with α1-adrenoceptors, reversed the suppressive effects of L-p-BT on norepinephrine-induced vasoconstriction. In vivo, L-p-BT administration achieved plasma levels of ≈60 µmol/L and inhibited mesenteric vascular responses to exogenous norepinephrine and sympathetic nerve stimulation. TNAP modulates vascular responses to norepinephrine likely by affecting positive cooperativity of α1-adrenoceptor signaling via a mechanism involving A1 receptor signaling.

Dietary polyacetylene falcarinol upregulated intestinal heme oxygenase-1 and modified plasma cytokine profile in late phase lipopolysaccharide-induced acute inflammation in CB57BL/6 mice.

Unlike polyphenols, which are widely available in the diet, polyacetylenes are available only from the Apiaceae family vegetables, including carrot, parsnip, fennel, celery, and many herbs (parsley, lovage, etc). The aim of this study was to investigate the hypothesis that polyacetylene falcarinol (FA) reduces intestinal inflammation and examine its similarity of effect to isothiocyanate R-sulforaphane during the late phase of acute inflammation. To this end, 3-month-old male CB57BL/6 mice were fed twice daily for 1 week with 5 mg/kg of FA, sulforaphane, or vehicle before receiving an intraperitoneal injection of 5 mg/kg endotoxin (lipopolysaccharide [LPS]) to induce modest acute inflammation. The expression of intestinal and hepatic heme oxygenase-1 at the mRNA and protein levels, circulating cytokines, as well as intestinal and mesenteric n-6 and n-3 fatty acid lipid mediators was compared 24 hours after LPS administration to examine its effects on the late phase of inflammation. Intestinal nuclear factor (erythroid-derived 2)-like 2 target enzyme heme oxygenase-1 was upregulated 8.42-fold at the mRNA level and 10.7-fold at the protein level by FA-supplemented diet. However, the FA-supplemented diet produced a unique type-2 plasma cytokine skew after LPS treatment. Plasma cytokines interleukin (IL)-4, IL-13, IL-9, and IL-10 were upregulated, reflecting the cytokine profile of reduced type 1 inflammation. A detailed lipidomic analysis of n-6 and n-3 fatty acid pro- and anti-inflammatory pathways in the mesentery and intestinal mucosa showed that FA diet was more similar to the control groups than to other LPS treated groups. In this study, we demonstrated that FA-supplemented diet produced a unique immunomodulatory effect not observed with sulforaphane in late phases of inflammation. These results support the hypothesis that FA may have role as a dietary immunosuppressant in patients with inflammatory gastrointestinal as well as other inflammatory disorders that may be alleviated by increasing consumption of carrot or other FA-containing food sources.