Palmitoylethanolamide Modulates Inflammation-Associated Vascular Endothelial Growth Factor (VEGF) Signaling via the Akt/mTOR Pathway in a Selective Peroxisome Proliferator-Activated Receptor Alpha (PPAR-α)-Dependent Manner

New insights in the mechanisms of opioid analgesia and tolerance: Ultramicronized palmitoylethanolamide down-modulates vascular endothelial growth factor-A in the nervous system

Growing evidence suggests that opioid analgesics modulate angiogenesis during pathophysiological processes. Vascular endothelial growth factor-A (VEGF-A) was recently proposed to be involved in pain development. To date, no anti-angiogenic drug is used for pain management. When administered in a bioavailable formulation, (i.e., ultramicronized) N-palmitoylethanolamine (PEA) delays the onset of morphine tolerance, improves morphine analgesic activity and reduces angiogenesis in in vivo models. This study aimed at investigating whether VEGF-A is involved in PEA-induced delay of morphine tolerance. The anti-VEGF-A monoclonal antibody bevacizumab was used as a reference drug. Preemptive and concomitant treatment with ultramicronized PEA delayed morphine tolerance and potentiated the analgesic effect of morphine, while counteracting morphine-induced increase of VEGF-A in the nervous system. Similar results were obtained when bevacizumab was administered together with morphine. Of note, bevacizumab showed an analgesic effect per se. In equianalgesic treatment regimens (obtained through increasing morphine doses and associating PEA), PEA resulted in lower expression of VEGF-A in dorsal root ganglia (DRG) and spinal cord compared to morphine alone. Similar results were observed for plasma levels of the soluble VEGF receptor 1 (sFLT-1). Moreover, in morphine-treated animals, two pain-related genes (i.e., Serpina3n and Eaat2) showed a more than 3-fold increase in their expression at spinal cord and DRG level, with the increase being significantly counteracted by PEA treatment. This study supports the hypothesis that the effects of PEA on morphine analgesia and tolerance may be mediated by the down-modulation of VEGF-A and sFLT-1 in the nervous system and plasma, respectively.

N-palmitoyl-d-glucosamine limits mucosal damage and VEGF-mediated angiogenesis by PPARα-dependent suppression of pAkt/mTOR/HIF1α pathway and increase in PEA levels in AOM/DSS colorectal carcinoma in mice

Chronic intestinal inflammation and neo-angiogenesis are interconnected in colorectal carcinoma (CRC) pathogenesis. Molecules reducing inflammation and angiogenesis hold promise for CRC prevention and treatment. N-Palmitoyl-d-glucosamine (PGA), a natural glycolipid analog with anti-inflammatory properties, has shown efficacy against acute colitis. Micronized PGA (mPGA) formulations exhibit superior anti-inflammatory activity. This study investigates the in vivo anti-angiogenic and protective effects of mPGA in a mouse model of colitis-associated CRC induced by azoxymethane/dextran sodium sulfate (AOM/DSS). CRC was induced in C57BL/6J mice using intraperitoneal azoxymethane followed by three cycles of 2.5% dextran sodium sulfate (DSS) in drinking water. Mice were treated with mPGA (30-150 mg/kg) with or without the PPARα inhibitor MK886 (10 mg/kg). At Day 70 post-azoxymethane injection, mice underwent anesthetized endoscopic colon evaluation. Post-mortem analysis of tumorigenesis and angiogenesis was performed using histological, immunohistochemical, and immunoblotting techniques. mPGA improved disease progression and survival rates in a dose- and PPARα-dependent manner in AOM/DSS-exposed mice. It reduced polyp formation, decreased pro-angiogenic CD31, pro-proliferative Ki67, and pro-inflammatory TLR4 expression levels, and inhibited VEGF and MMP-9 secretion by disrupting the pAkt/mTOR/HIF1α pathway. mPGA increased colon PEA levels, restoring anti-tumoral PPARα and wtp53 protein expression. Given its lack of toxicity, mPGA shows potential as a nutritional intervention to counteract inflammation-related angiogenesis in CRC.

Exploration of the molecular linkage between endometriosis and Crohn disease by bioinformatics methods

BACKGROUND

Endometriosis (EMT) is a common disease in reproductive-age woman and Crohn disease (CD) is a chronic inflammatory disorder in gastrointestinal tract. Previous studies reported that patients with EMT had an increased risk of CD. However, the linkage between EMT and CD remains unclear. In this study, we aimed to investigate the potential molecular mechanism of EMT and CD.

METHODS

The microarray data of EMT and CD were downloaded from Gene Expression Omnibus. Common genes of EMT and CD were obtained to perform the Gene Ontology and Kyoto Encyclopedia of Gene Genomes enrichments. The protein-protein interaction network was constructed by Cytoscape software and the hub genes were identified by CytoHubba plug-in. Finally we predicted the transcription factors (TFs) of hub genes and constructed a TFs-hub genes regulation network.

RESULTS

A total of 50 common genes were identified. Kyoto Encyclopedia of Gene Genomes enrichment showed that the common genes mainly enriched in MAPK pathway, VEGF pathway, Wnt pathway, TGF-beta pathway, and Ras pathway. Fifteen hub genes were collected from the protein-protein interaction network, including FMOD, FRZB, CPE, SST, ISG15, EFEMP1, KDR, ADRA2A, FZD7, AQP1, IGFBP5, NAMPT, PLUA, FGF9, and FHL2. Among them, FGF9, FZD7, IGFBP5, KDR, and NAMPT were both validated in the other 2 datasets. Finally TFs-hub genes regulation network were constructed.

CONCLUSION

Our findings firstly revealed the linkage between EMT and CD, including inflammation, angiogenesis, immune regulation, and cell behaviors, which may lead to the risk of CD in EMT. FGF9, FZD7, IGFBP5, KDR, and NAMPT may closely relate to the linkage.

Amelioration of Dextran Sodium Sulfate-Induced Colitis in Mice through Oral Administration of Palmitoylethanolamide

Inflammatory bowel disease (IBD) is a group of chronic disorders characterized by pain, ulceration, and the inflammation of the gastrointestinal tract (GIT) and categorized into two major subtypes: ulcerative colitis (UC) and Crohn's disease. The inflammation in UC is typically restricted to the mucosal surface, beginning in the rectum and extending through the entire colon. UC patients typically show increased levels of pro-inflammatory cytokines, leading to intestinal epithelial apoptosis and mucosal inflammation, which impair barrier integrity. Chronic inflammation is associated with the rapid recruitment and inappropriate retention of leukocytes at the site of inflammation, further amplifying the inflammation. While UC can be managed using a number of treatments, these drugs are expensive and cause unwanted side effects. Therefore, a safe and effective treatment for UC patients is needed. Palmitoylethanolamide (PEA) is an endogenous fatty acid amide and an analog of the endocannabinoid anandamine. PEA administration has been found to normalize intestinal GIT motility and reduce injury in rodents and humans. In the current study, we examined the efficacy of PEA encapsulated in phytosomes following oral administration in experimental ulcerative colitis. Here, we showed that PEA at a human-equivalent dose of 123 mg/kg (OD or BID) attenuated DSS-induced experimental colitis as represented by the reduction in clinical signs of colitis, reduction in gross mucosal injury, and suppression of leukocyte recruitment at inflamed venules. These findings add to the growing body of data demonstrating the beneficial effects of PEA to control the acute phase of intestinal inflammation occurring during UC.

Anxiogenic doses of rapamycin prevent URB597-induced anti-stress effects in socially defeated mice

Repeated exposure to psychosocial stress modulates the endocannabinoid system, particularly anandamide (AEA) signaling in brain regions associated with emotional distress. The mTOR protein regulates various neuroplastic processes in the brain disrupted by stress, including adult hippocampal neurogenesis. This kinase has been implicated in multiple effects of cannabinoid drugs and the anti-stress behavioral effects of psychoactive drugs. Therefore, our hypothesis is that enhancing AEA signaling via pharmacological inhibition of the fatty acid amide hydrolase (FAAH) enzyme induces an anti-stress behavioral effect through an mTOR-dependent mechanism. To test this hypothesis, male C57Bl6 mice were exposed to social defeat stress (SDS) for 7 days and received daily treatment with either vehicle or different doses of the FAAH inhibitor, URB597 (0.1; 0.3; 1 mg/Kg), alone or combined with rapamycin. The results suggested that URB597 induced an inverted U-shaped dose-response curve in mice subjected to SDS (with the intermediate dose of 0.3 mg/kg being anxiolytic, and the higher tested dose of 1 mg/Kg being anxiogenic). In a second independent experiment, rapamycin treatment induced an anxiogenic-like response in control mice. However, in the presence of rapamycin, the anxiolytic dose of URB597 treatment failed to reduce stress-induced anxiety behaviors in mice. SDS exposure altered the hippocampal expression of the mTOR scaffold protein Raptor. Furthermore, the anxiogenic dose of URB597 decreased the absolute number of migrating doublecortin (DCX)-positive cells in the dentate gyrus, suggesting an anti-anxiety effect independent of newly generated/immature neurons. Therefore, our results indicate that in mice exposed to repeated psychosocial stress, URB597 fails to counteract the anxiogenic-like response induced by the pharmacological dampening of mTOR signaling.

Molecular mechanisms and therapeutic perspectives of peroxisome proliferator-activated receptor α agonists in cardiovascular health and disease

The prevalence of cardiovascular disease (CVD) has been rising due to sedentary lifestyles and unhealthy dietary patterns. Peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor regulating multiple biological processes, such as lipid metabolism and inflammatory response critical to cardiovascular homeostasis. Healthy endothelial cells (ECs) lining the lumen of blood vessels maintains vascular homeostasis, where endothelial dysfunction associated with increased oxidative stress and inflammation triggers the pathogenesis of CVD. PPARα activation decreases endothelial inflammation and senescence, contributing to improved vascular function and reduced risk of atherosclerosis. Phenotypic switch and inflammation of vascular smooth muscle cells (VSMCs) exacerbate vascular dysfunction and atherogenesis, in which PPARα activation improves VSMC homeostasis. Different immune cells participate in the progression of vascular inflammation and atherosclerosis. PPARα in immune cells plays a critical role in immunological events, such as monocyte/macrophage adhesion and infiltration, macrophage polarization, dendritic cell (DC) embedment, T cell activation, and B cell differentiation. Cardiomyocyte dysfunction, a major risk factor for heart failure, can also be alleviated by PPARα activation through maintaining cardiac mitochondrial stability and inhibiting cardiac lipid accumulation, oxidative stress, inflammation, and fibrosis. This review discusses the current understanding and future perspectives on the role of PPARα in the regulation of the cardiovascular system as well as the clinical application of PPARα ligands.

Palmitoylethanolamide counteracts high-fat diet-induced gut dysfunction by reprogramming microbiota composition and affecting tryptophan metabolism

Obesity is associated with gastrointestinal (GI) tract and central nervous system (CNS) disorders. High-fat diet (HFD) feeding-induced obesity in mice induces dysbiosis, causing a shift toward bacteria-derived metabolites with detrimental effects on metabolism and inflammation: events often contributing to the onset and progression of both GI and CNS disorders. Palmitoylethanolamide (PEA) is an endogenous lipid mediator with beneficial effects in mouse models of GI and CNS disorders. However, the mechanisms underlining its enteroprotective and neuroprotective effects still need to be fully understood. Here, we aimed to study the effects of PEA on intestinal inflammation and microbiota alterations resulting from lipid overnutrition. Ultramicronized PEA (30 mg/kg/die per os) was administered to HFD-fed mice for 7 weeks starting at the 12th week of HFD regimen. At the termination of the study, the effects of PEA on inflammatory factors and cells, gut microbial features and tryptophan (TRP)-kynurenine metabolism were evaluated. PEA regulates the crosstalk between the host immune system and gut microbiota via rebalancing colonic TRP metabolites. PEA treatment reduced intestinal immune cell recruitment, inflammatory response triggered by HFD feeding, and corticotropin-releasing hormone levels. In particular, PEA modulated HFD-altered TRP metabolism in the colon, rebalancing serotonin (5-HT) turnover and reducing kynurenine levels. These effects were associated with a reshaping of gut microbiota composition through increased butyrate-promoting/producing bacteria, such as Bifidobacterium, Oscillospiraceae and Turicibacter sanguinis, with the latter also described as 5-HT sensor. These data indicate that the rebuilding of gut microbiota following PEA supplementation promotes host 5-HT biosynthesis, which is crucial in regulating intestinal function.

The emerging role of PPAR-alpha in breast cancer

Breast cancer has been confirmed to have lipid disorders in the tumour microenvironment. Peroxisome proliferator-activated receptor alpha (PPARα) is a ligand-activated transcriptional factor that belongs to the family of nuclear receptors. PPARα regulates the expression of genes involved in fatty acid homeostasis and is a major regulator of lipid metabolism. Because of its effects on lipid metabolism, an increasing number of studies have investigated the relationship of PPARα with breast cancer. PPARα has been shown to impact the cell cycle and apoptosis in normal cells and tumoral cells through regulating genes of the lipogenic pathway, fatty acid oxidation, fatty acid activation, and uptake of exogenous fatty acids. Besides, PPARα is involved in the regulation of the tumour microenvironment (anti-inflammation and inhibition of angiogenesis) by modulating different signal pathways such as NF-κB and PI3K/AKT/mTOR. Some synthetic PPARα ligands are used in adjuvant therapy for breast cancer. PPARα agonists are reported to reduce the side effects of chemotherapy and endocrine therapy. In addition, PPARα agonists enhance the curative effects of targeted therapy and radiation therapy. Interestingly, with the emerging role of immunotherapy, attention has been focused on the tumour microenvironment. The dual functions of PPARα agonists in immunotherapy need further research. This review aims to consolidate the operations of PPARα in lipid-related and other ways, as well as discuss the current and potential applications of PPARα agonists in tackling breast cancer.

Sestrin2 contributes to BRAF inhibitor resistance via reducing redox vulnerability of melanoma cells

BACKGROUND

Treatment resistance often occurs with BRAF inhibitor (BRAFi) therapy for melanoma, bringing in a great challenge to the treatment of melanoma patients harboring mutant BRAF gene. Recent studies revealed redox vulnerability constitutes a novel opportunity to overcome BRAFi resistance. Previously we found Sestrin2 provided protection to metastatic melanoma cells by detoxifying reactive oxygen species (ROS) induced by anoikis, but its defensive role against redox stimuli elicited by BRAFi was unclear.

OBJECTIVE

In-depth explored the role of Sestrin2 in BRAFi-resistant melanoma.

METHODS

Vemurafenib-resistant melanoma cells were established using 451Lu and UACC62 cell lines carrying BRAF^V600E mutation. Mechanistic studies were subsequently performed by transfection of lentiviral vectors encoding an shRNA against SESN2 or embedded with the coding sequences of SESN2 cDNA.

RESULTS

Elevated Sestrin2 expression was found in vemurafenib-resistance melanoma cells. Further mechanistic studies revealed that BRAFi-resistant melanoma cells employ Sestrin2 to adapt to higher oxidative stress under vemurafenib exposure. It was also demonstrated that mTOR signaling was significantly activated following Sestrin2 knockdown. Given the known promoting role of active mTOR signaling in melanoma proliferation and survival, the effects of mTOR blocker and Sestrin2 ablation on BRAFi-resistant melanoma cells were further tested, and the combination was found to result in enhanced inhibition of melanoma cell growth.

CONCLUSIONS

Our findings demonstrated the contribution of Sestrin2 to the development of BRAFi resistance and the fact that the combination of mTOR blocker assisted Sestrein2 ablation in eliminating BRAFi resistance of melanoma. Therefore, mTOR and Sestrin2 may be novel combinatorial therapeutic targets to overcome BRAFi resistance of melanoma.

RNA-Seq Reveals Protective Mechanisms of Mongolian Medicine Molor-Dabos-4 on Acute Indomethacin-Induced Gastric Ulcers in Rats

This study aimed to apply transcriptomics to determine how Molor-Dabos-4 (MD-4) protects healthy rats against indomethacin (IND)-induced gastric ulcers and to identify the mechanism behind this protective effect. Rats were pretreated with MD-4 (0.3, 1.5, or 3 g/kg per day) for 21 days before inducing gastric ulcers by oral administration with indomethacin (30 mg/kg). Unulcerated and untreated healthy rats were used as controls. Effects of the treatment were assessed based on the ulcer index, histological and pathological examinations, and indicators of inflammation, which were determined by enzyme-linked immunosorbent assay. Transcriptomic analysis was performed for identifying potential pharmacological mechanisms. Eventually, after identifying potential target genes, the latter were validated by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). After pretreatment with MD-4, gastric ulcers, along with other histopathological features, were reduced. MD-4 significantly (p < 0.05) increased the superoxide dismutase (SOD) levels in ulcers and reduced pepsin, TNF-α, and IL-6 levels. RNA-seq analysis identified a number of target genes on which MD-4 could potentially act. Many of these genes were involved in pathways that were linked to anti-inflammatory and antioxidant responses, and other protective mechanisms for the gastric mucosa. qRT-PCR showed that altered expression of the selected genes, such as Srm, Ryr-1, Eno3, Prkag3, and Eef1a2, was consistent with the transcriptome results. MD-4 exerts protective effects against IND-induced gastric ulcers by reducing inflammatory cytokines and pepsin and increasing the expression of SOD levels. Downregulation of Srm, Ryr-1, Eno3, Prkag3, and Eef1a2 genes involved in regulating arginine and proline metabolism, calcium signaling pathway, HIF-1 signaling pathway, oxytocin signaling pathway, and legionellosis are possibly involved in MD-4-mediated protection against gastric ulcers.

The Use of Palmitoylethanolamide in the Treatment of Long COVID: A Real-Life Retrospective Cohort Study

COVID-19 can cause symptoms that last weeks or months after the infection has gone, with a significant impairment of quality of life. Palmitoylethanolamide (PEA) is a naturally occurring lipid mediator that has an entourage effect on the endocannabinoid system mitigating the cytokine storm. The aim of this retrospective study is to evaluate the potential efficacy of PEA in the treatment of long COVID. Patients attending the Neurological Out Clinic of the IRCCS Centro Neurolesi Bonino-Pulejo (Messina, Italy) from August 2020 to September 2021 were screened for potential inclusion in the study. We included only long COVID patients who were treated with PEA 600 mg two times daily for about 3 months. All patients performed the post-COVID-19 Functional Status (PCFS) scale. Thirty-three patients (10 males, 43.5%, mean age 47.8 ± 12.4) were enrolled in the study. Patients were divided into two groups based on hospitalization or home care observation. A substantial difference in the PCFS score between the two groups at baseline and after treatment with PEA were found. We found that smoking was a risk factor with an odds ratio of 8.13 CI 95% [0.233, 1.167]. Our findings encourage the use of PEA as a potentially effective therapy in patients with long COVID.

Oral Adelmidrol Administration Up-Regulates Palmitoylethanolamide Production in Mice Colon and Duodenum through a PPAR-γ Independent Action

Adelmidrol is a promising palmitoylethanolamide (PEA) analog which displayed up-and-coming anti-inflammatory properties in several inflammatory conditions. Recent studies demonstrated that Adelmidrol is an in vitro enhancer of PEA endogenous production, through the so called “entourage” effect. The present study investigated the ability of Adelmidrol (1 and 10 mg/Kg per os) to increase the endogenous level of PEA in the duodenum and colon of mice after 21-day oral administration in the presence and absence of PPAR-γ inhibitor (1 mg/kg). The level of PEA was analyzed by HPLC-MS. The expression of PEA-related enzymatic machinery was evaluated by western blot and RT-PCR analysis. Our findings demonstrated that Adelmidrol significantly increased PEA levels in the duodenum and colon in a dose/time-dependent manner. We also revealed that Adelmidrol up regulated the enzymatic machinery responsible for PEA metabolism and catabolism. Interestingly, the use of the selective irreversible PPAR-γ antagonist did not affect either PEA intestinal levels or expression/transcription of PEA metabolic enzymes following Adelmidrol administration. The “entourage effect” with Adelmidrol as an enhancer of PEA was thus PPAR-γ-independent. The findings suggest that Adelmidrol can maximize a PEA therapeutic-based approach in several intestinal morbidities.

Comprehensive lipidomics of lupus-prone mice using LC-MS/MS identifies the reduction of palmitoylethanolamide that suppresses TLR9-mediated inflammation

Lipid mediators are known to play crucial roles not only in the onset of the inflammatory response but also in the induction of resolution of inflammation. Here we report that palmitoylethanolamide (PEA), an endogenous N-acylethanolamine, can suppress the inflammation induced by Toll-like receptor (TLR) signaling both in vitro and in vivo. PEA was found to be significantly reduced in the serum and spleen of lupus-prone MRL/lpr mice analyzed by lipidomics. PEA suppressed pro-inflammatory cytokine production in a mouse macrophage cell line stimulated with TLR ligands such as lipopolysaccharide, peptidoglycan, poly (I:C), imiquimod and CpG-ODN. PEA also inhibited both mRNA and protein levels of IL-6 in bone marrow derived dendritic cells (BMDCs) and B cells stimulated with CpG-ODN. Augmentation of cell surface CD86 and CD40 on BMDCs and B cells, IgM production and cell proliferation of B cells in response to CpG-ODN were attenuated by PEA. Moreover, PEA treatment significantly reduced mortality and serum IL-6 levels in mice injected with CpG-ODN plus D-galactosamine. Taken together, PEA ameliorates inflammation induced by TLR signaling, which could be a novel therapeutic target for inflammatory disorders. This article is protected by copyright. All rights reserved.

Nutraceuticals and Diet Supplements in Crohn's Disease: A General Overview of the Most Promising Approaches in the Clinic

Crohn's disease (CD) is a chronic inflammatory gastrointestinal disorder requiring lifelong medications. The currently approved drugs for CD are associated with relevant side effects and several studies suggest an increased use of nutraceuticals among CD patients, seeking for what is perceived as a more "natural" approach in controlling this highly morbid condition. Nutraceuticals are foods or foods' components with beneficial health properties that could aid in CD treatment for their anti-inflammatory, analgesic and immunoregulatory activities that come along with safety, high tolerability, easy availability and affordability. Depending on their biological effect, nutraceuticals' support could be employed in different subsets of CD patients, both those with active disease, as adjunctive immunomodulatory therapies, and/or in quiescent disease to provide symptomatic relief in patients with residual functional symptoms. Despite the increasing interest of the general public, both limited research and lack of education from healthcare professionals regarding their real clinical effectiveness account for the increasing number of patients turning to unconventional sources. Professionals should recognize their widespread use and the evidence base for or against their efficacy to properly counsel IBD patients. Overall, nutraceuticals appear to be safe complements to conventional therapies; nonetheless, little quality evidence supports a positive impact on underlying inflammatory activity.

The Complex Relationship Between Microbiota, Immune Response and Creeping Fat in Crohn's Disease

In the last decade, there has been growing interest in the pathological involvement of hypertrophic mesenteric fat attached to the serosa of the inflamed intestinal segments involved in Crohn's disease [CD], known as creeping fat. In spite of its protective nature, creeping fat harbours an aberrant inflammatory activity which, in an already inflamed intestine, may explain why creeping fat is associated with a greater severity of CD. The transmural inflammation of CD facilitates the interaction of mesenteric fat with translocated intestinal microorganisms, contributing to activation of the immune response. This may be not the only way in which microorganisms alter the homeostasis of this fatty tissue: intestinal dysbiosis may also impair xenobiotic metabolism. All these CD-related alterations have a functional impact on nuclear receptors such as the farnesoid X receptor or the peroxisome proliferator-activated receptor γ, which are implicated in regulation of the immune response, adipogenesis and the maintenance of barrier function, as well as on creeping fat production of inflammatory-associated cells such as adipokines. The dysfunction of creeping fat worsens the inflammatory course of CD and may favour intestinal fibrosis and fistulizing complications. However, our current knowledge of the pathophysiology and pathogenic role of creeping fat is controversial and a better understanding might provide new therapeutic targets for CD. Here we aim to review and update the key cellular and molecular alterations involved in this inflammatory process that link the pathological components of CD with the development of creeping fat.

Recombinant human growth hormone improves the immune status of rats with septic encephalopathy: The role of VEGFR2 in the prevalence of endoplasmic reticulum stress repair module

Septic encephalopathy results from the intense reaction of the immune system to infection. The role of growth hormone (GH) signaling in maintaining brain function is well established; however, the involvement of the vascular endothelial growth factor receptor-2 (VEGFR2) in the potential modulatory effect of GH on septic encephalopathy-associated endoplasmic reticulum stress (ERS) and blood-brain barrier (BBB) permeability is not well-understood. Therefore, after the induction of mid-grade sepsis by cecal ligation/perforation, rats were subcutaneously injected with recombinant human GH (rhGH)/somatropin alone or preceded by the VEGFR2 antagonist WAG-4S for 7 days. rhGH/somatropin reduced bodyweight loss and plasma endotoxin, maintained the hyperthermic state, and improved motor/memory functions. Additionally, rhGH/somatropin increased the junctional E-cadherin and β-catenin pool in the cerebral cortex to enhance the BBB competency, effects that were abolished by VEGFR2 blockade. Also, it activated cortical VEGFR2/mammalian target of the Rapamycin (mTOR) axis to mitigate ERS. The latter was reflected by the deactivation of the inositol-requiring enzyme-1α (IRE1α)/spliced X-box binding protein-1 (XBP1s) trajectory and the reduction in the protein levels of the death markers, C/EBP homologous protein (CHOP)/growth arrest and DNA damage-153 (GADD153), c-jun-N-terminal kinase (JNK), and caspase-3 with the simultaneous augmentation of expression of the unfolded protein response transducer proteinkinaseR-like ERkinase (PERK). Furthermore, rhGH/somatropin suppressed the phosphorylation of eukaryotic initiation factor-2α (eIF2α), upregulated the gene expression of activating transcription factor-4 (ATF4), GADD34, and glucose-regulated protein-78/binding immunoglobulin (GRP78/Bip). Moreover, it increased the glutathione level and reduced lipid peroxidation in the cerebral cortex. The VEGFR2 antagonist reversed the effect of rhGH/somatropin on PERK and IRE1α and boosted the apoptotic markers but neither affected p-eIF2α nor GADD34. Hence, we conclude that VEGFR2 activation by rhGH/somatropin plays a crucial role in assembling the BBB adherens junctions via its antioxidant capacity, ERS relief, and reducing endotoxemia in septic encephalopathy.

Phytotherapics in COVID19: Why palmitoylethanolamide?

At present, googling the search terms "COVID-19" and "Functional foods" yields nearly 500,000,000 hits, witnessing the growing interest of the scientific community and the general public in the role of nutrition and nutraceuticals during the COVID-19 pandemic. Many compounds have been proposed as phytotherapics in the prevention and/or treatment of COVID-19. The extensive interest of the general public and the enormous social media coverage on this topic urges the scientific community to address the question of whether which nutraceuticals can actually be employed in preventing and treating this newly described coronavirus-related disease. Recently, the Canadian biotech pharma company "FSD Pharma" received the green light from the Food and Drug Administration to design a proof-of-concept study evaluating the effects of ultramicronized palmitoylethanolamide (PEA) in COVID-19 patients. The story of PEA as a nutraceutical to prevent and treat infectious diseases dates back to the 1970s where the molecule was branded under the name Impulsin and was used for its immunomodulatory properties in influenza virus infection. The present paper aims at analyzing the potential of PEA as a nutraceutical and the previous evidence suggesting its anti-inflammatory and immunomodulatory properties in infectious and respiratory diseases and how these could translate to COVID-19 care.

A Palmitoylethanolamide Producing Lactobacillus paracasei Improves Clostridium difficile Toxin A-Induced Colitis

Genetically engineered probiotics, able to in situ deliver therapeutically active compounds while restoring gut eubiosis, could represent an attractive therapeutic alternative in Clostridium difficile infection (CDI). Palmitoylethanolamide is an endogenous lipid able to exert immunomodulatory activities and restore epithelial barrier integrity in human models of colitis, by binding the peroxisome proliferator–activated receptor-α (PPARα). The aim of this study was to explore the efficacy of a newly designed PEA-producing probiotic (pNAPE-LP) in a mice model of C. difficile toxin A (TcdA)-induced colitis. The human N-acyl-phosphatidylethanolamine-specific phospholipase D (NAPE-PLD), a key enzyme involved in the synthesis of PEA, was cloned and expressed in a Lactobacillus paracasei that was intragastrically administered to mice 7 days prior the induction of the colitis. Bacteria carrying the empty vector served as negative controls (pLP).In the presence of palmitate, pNAPE-LP was able to significantly increase PEA production by 27,900%, in a time- and concentration-dependent fashion. Mice treated with pNAPE-LP showed a significant improvement of colitis in terms of histological damage score, macrophage count, and myeloperoxidase levels (−53, −82, and −70.4%, respectively). This was paralleled by a significant decrease both in the expression of toll-like receptor-4 (−71%), phospho-p38 mitogen-activated protein kinase (−72%), hypoxia-inducible factor-1-alpha (−53%), p50 (−74%), and p65 (−60%) and in the plasmatic levels of interleukin-6 (−86%), nitric oxide (−59%), and vascular endothelial growth factor (−71%). Finally, tight junction protein expression was significantly improved by pNAPE-LP treatment as witnessed by the rescue of zonula occludens-1 (+304%), Ras homolog family member A-GTP (+649%), and occludin expression (+160%). These protective effects were mediated by the specific release of PEA by the engineered probiotic as they were abolished in PPARα knockout mice and in wild-type mice treated with pLP. Herein, we demonstrated that pNAPE-LP has therapeutic potential in CDI by inhibiting colonic inflammation and restoring tight junction protein expression in mice, paving the way to next generation probiotics as a promising strategy in CDI prevention.

Engineered Lactobacillus paracasei Producing Palmitoylethanolamide (PEA) Prevents Colitis in Mice

Palmitoylethanolamide (PEA) is an N-acylethanolamide produced on-demand by the enzyme N-acylphosphatidylethanolamine-preferring phospholipase D (NAPE-PLD). Being a key member of the larger family of bioactive autacoid local injury antagonist amides (ALIAmides), PEA significantly improves the clinical and histopathological stigmata in models of ulcerative colitis (UC). Despite its safety profile, high PEA doses are required in vivo to exert its therapeutic activity; therefore, PEA has been tested only in animals or human biopsy samples, to date. To overcome these limitations, we developed an NAPE-PLD-expressing Lactobacillus paracasei F19 (pNAPE-LP), able to produce PEA under the boost of ultra-low palmitate supply, and investigated its therapeutic potential in a murine model of UC. The coadministration of pNAPE-LP and palmitate led to a time-dependent release of PEA, resulting in a significant amelioration of the clinical and histological damage score, with a significantly reduced neutrophil infiltration, lower expression and release of pro-inflammatory cytokines and oxidative stress markers, and a markedly improved epithelial barrier integrity. We concluded that pNAPE-LP with ultra-low palmitate supply stands as a new method to increase the in situ intestinal delivery of PEA and as a new therapeutic able of controlling intestinal inflammation in inflammatory bowel disease.

The Basal Pharmacology of Palmitoylethanolamide

Palmitoylethanolamide (PEA, N-hexadecanoylethanolamide) is an endogenous compound belonging to the family of N-acylethanolamines. PEA has anti-inflammatory and analgesic properties and is very well tolerated in humans. In the present article, the basal pharmacology of PEA is reviewed. In terms of its pharmacokinetic properties, most work has been undertaken upon designing formulations for its absorption and upon characterising the enzymes involved in its metabolism, but little is known about its bioavailability, tissue distribution, and excretion pathways. PEA exerts most of its biological effects in the body secondary to the activation of peroxisome proliferator-activated receptor-α (PPAR-α), but PPAR-α-independent pathways involving other receptors (Transient Receptor Potential Vanilloid 1 (TRPV1), GPR55) have also been identified. Given the potential clinical utility of PEA, not least for the treatment of pain where there is a clear need for new well-tolerated drugs, we conclude that the gaps in our knowledge, in particular those relating to the pharmacokinetic properties of the compound, need to be filled.

The Protective Effects of Pre- and Post-Administration of Micronized Palmitoylethanolamide Formulation on Postoperative Pain in Rats

Background: Postoperative pain (PO) is a common form of acute pain. Inadequate PO treatment is an important health problem, as it leads to worse outcomes, such as chronic post-surgical pain. Therefore, it is necessary to acquire new knowledge on PO mechanisms to develop therapeutic options with greater efficacy than those available today and to lower the risk of adverse effects. For this reason, we evaluated the ability of micronized palmitoylethanolamide (PEA-m) to resolve the pain and inflammatory processes activated after incision of the hind paw in an animal model of PO. Methods: The animals were subjected to surgical paw incision and randomized into different groups. PEA-m was administered orally at 10 mg/kg at different time points before or after incision. Results: Our research demonstrated that the pre- and post-treatment with PEA-m reduced the activation of mast cells at the incision site and the expression of its algogenic mediator nerve growth factor (NGF) in the lumbar spinal cord. Furthermore, again at the spinal level, it was able to decrease the activation of phospho-extracellular signal-regulated kinases (p-ERK), ionized calcium binding adaptor molecule 1 (Iba1), glial fibrillary acidic protein (GFAP), and the expression of brain-derived neurotrophic factor (BDNF). PEA-m also reduced the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) spinal pathway, showing a protective effect in a rat model of PO. Conclusion: The results obtained reinforce the idea that PEA-m may be a potential treatment for the control of pain and inflammatory processes associated with PO. In addition, pre- and post-treatment with PEA-m is more effective than treatment alone after the surgery and this limits the time of taking the compound and the abuse of analgesics.

Impaired Duodenal Palmitoylethanolamide Release Underlies Acid-Induced Mast Cell Activation in Functional Dyspepsia

BACKGROUND & AIMS

Acid hypersensitivity is claimed to be a symptomatic trigger in functional dyspepsia (FD); however, the neuroimmune pathway(s) and the mediators involved in this process have not been investigated systematically. Palmitoylethanolamide (PEA) is an endogenous compound, able to modulate nociception and inflammation, but its role in FD has not been assessed.

METHODS

Duodenal biopsy specimens from FD and control subjects, and peroxisome proliferator-activated receptor-α (PPARα) null mice were cultured at a pH of 3.0 and 7.4. Mast cell (MC) number, the release of their mediators, and the expression of transient receptor potential vanilloid receptor (TRPV)1 and TRPV4, were evaluated. All measurements also were performed in the presence of a selective blocker of neuronal action potential (tetradotoxin). FD and control biopsy specimens in acidified medium also were incubated in the presence of different PEA concentrations, alone or combined with a selective PPARα or PPAR-γ antagonist.

RESULTS

An acid-induced increase in MC density and the release of their mediators were observed in both dyspeptic patients and controls; however, this response was amplified significantly in FD. This effect was mediated by submucosal nerve fibers and up-regulation of TRPV1 and TRPV4 receptors because pretreatment with tetradotoxin significantly reduced MC infiltration. The acid-induced endogenous release of PEA was impaired in FD and its exogenous administration counteracts MC activation and TRPV up-regulation.

CONCLUSIONS

Duodenal acid exposure initiates a cascade of neuronal-mediated events culminating in MC activation and TRPV overexpression. These phenomena are consequences of an impaired release of endogenous PEA. PEA might be regarded as an attractive therapeutic strategy for the treatment of FD.

Fatty Acids and Membrane Lipidomics in Oncology: A Cross-Road of Nutritional, Signaling and Metabolic Pathways

Fatty acids are closely involved in lipid synthesis and metabolism in cancer. Their amount and composition are dependent on dietary supply and tumor microenviroment. Research in this subject highlighted the crucial event of membrane formation, which is regulated by the fatty acids' molecular properties. The growing understanding of the pathways that create the fatty acid pool needed for cell replication is the result of lipidomics studies, also envisaging novel fatty acid biosynthesis and fatty acid-mediated signaling. Fatty acid-driven mechanisms and biological effects in cancer onset, growth and metastasis have been elucidated, recognizing the importance of polyunsaturated molecules and the balance between omega-6 and omega-3 families. Saturated and monounsaturated fatty acids are biomarkers in several types of cancer, and their characterization in cell membranes and exosomes is under development for diagnostic purposes. Desaturase enzymatic activity with unprecedented de novo polyunsaturated fatty acid (PUFA) synthesis is considered the recent breakthrough in this scenario. Together with the link between obesity and cancer, fatty acids open interesting perspectives for biomarker discovery and nutritional strategies to control cancer, also in combination with therapies. All these subjects are described using an integrated approach taking into account biochemical, biological and analytical aspects, delineating innovations in cancer prevention, diagnostics and treatments.

Associated Targets of the Antioxidant Cardioprotection of Ganoderma lucidum in Diabetic Cardiomyopathy by Using Open Targets Platform: A Systematic Review

Even with substantial advances in cardiovascular therapy, the morbidity and mortality rates of diabetic cardiomyopathy (DCM) continually increase. Hence, a feasible therapeutic approach is urgently needed. Objectives. This work is aimed at systemically reviewing literature and addressing cell targets in DCM through the possible cardioprotection of G. lucidum through its antioxidant effects by using the Open Targets Platform (OTP) website. Methods. The OTP website version of 19.11 was accessed in December 2019 to identify the studies in DCM involving G. lucidum. Results. Among the 157 cell targets associated with DCM, the mammalian target of rapamycin (mTOR) was shared by all evidence, drug, and text mining data with 0.08 score association. mTOR also had the highest score association 0.1 with autophagy in DCM. Among the 1731 studies of indexed PubMed articles on G. lucidum published between 1985 and 2019, 33 addressed the antioxidant effects of G. lucidum and its molecular signal pathways involving oxidative stress and therefore were included in the current work. Conclusion. mTOR is one of the targets by DCM and can be inhibited by the antioxidative properties of G. lucidum directly via scavenging radicals and indirectly via modulating mTOR signal pathways such as Wnt signaling pathway, Erk1/2 signaling, and NF-κB pathways.

Cathepsin K Knockout Exacerbates Haemorrhagic Transformation Induced by Recombinant Tissue Plasminogen Activator After Focal Cerebral Ischaemia in Mice

Severe haemorrhagic transformation (HT), a common complication of recombinant tissue plasminogen activator (rtPA) treatment, predicts poor clinical outcomes in acute ischaemic stroke. The search for agents to mitigate this effect includes investigating biomolecules involved in neovascularization. This study examines the role of Cathepsin K (Ctsk) in rtPA-induced HT after focal cerebral ischaemia in mice. After knockout of Ctsk, the gene encoding Ctsk, the outcomes of Ctsk+/+ and Ctsk-/- mice were compared 24 h after rtPA-treated cerebral ischaemia with respect to HT severity, neurological deficits, brain oedema, infarct volume, number of apoptotic neurons and activated microglia/macrophage, blood-brain barrier integrity, vascular endothelial growth factor (VEGF) expression and Akt-mTOR pathway activation. We observed that haemoglobin levels, brain oedema and infarct volume were significantly greater and resulted in more severe neurological deficits in Ctsk-/- than in Ctsk+/+ mice. Consistent with our hypothesis, the number of NeuN-positive neurons was lower and the number of TUNEL-positive apoptotic neurons and activated microglia/macrophage was higher in Ctsk-/- than in Ctsk+/+ mice. Ctsk knockout mice exhibited more severe blood-brain barrier (BBB) disruption, with microvascular endothelial cells exhibiting greater VEGF expression and lower ratios of phospo-Akt/Akt and phospo-mTOR/mTOR than in Ctsk+/+ mice. This study is the first to provide molecular insights into Ctsk-regulated HT after cerebral ischaemia, suggesting that Ctsk deficiency may disrupt the BBB via Akt/mTOR/VEGF signalling, resulting in neurological deficits and neuron apoptosis. Ctsk administration has the potential as a novel modality for improving the safety of rtPA treatment following stroke.

Plant-Derived Alkaloids: The Promising Disease-Modifying Agents for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) represents a group of intestinal disorders with self-destructive and chronic inflammation in the digestive tract, requiring long-term medications. However, as many side effects and drug resistance are frequently encountered, safer and more effective agents for IBD treatment are urgently needed. Over the past few decades, a variety of natural alkaloids made of plants or medicinal herbs have attracted considerable interest because of the excellent antioxidant and anti-inflammatory properties; additionally, these alkaloids have been reported to reduce the colonic inflammation and damage in a range of colitic models. In this review paper, we summarize the recent findings regarding the anti-colitis activity of plant-derived alkaloids and emphasize their therapeutic potential for the treatment of IBD; obvious improvement of the colonic oxidative and pro-inflammatory status, significant preservation of the epithelial barrier function and positive modulation of the gut microbiota are the underlying mechanisms for the plant-derived alkaloids to treat IBD. Further clinical trials and preclinical studies to unravel the molecular mechanism are essential to promote the clinical translation of plant-derived alkaloids for IBD.

Cannabis, Cannabinoids, and the Endocannabinoid System-Is there Therapeutic Potential for Inflammatory Bowel Disease?

Cannabis sativa and its extracts have been used for centuries, both medicinally and recreationally. There is accumulating evidence that exogenous cannabis and related cannabinoids improve symptoms associated with inflammatory bowel disease [IBD], such as pain, loss of appetite, and diarrhoea. In vivo, exocannabinoids have been demonstrated to improve colitis, mainly in chemical models. Exocannabinoids signal through the endocannabinoid system, an increasingly understood network of endogenous lipid ligands and their receptors, together with a number of synthetic and degradative enzymes and the resulting products. Modulating the endocannabinoid system using pharmacological receptor agonists, genetic knockout models, or inhibition of degradative enzymes have largely shown improvements in colitis in vivo. Despite these promising experimental results, this has not translated into meaningful benefits for human IBD in the few clinical trials which have been conducted to date, the largest study being limited by poor medication tolerance due to the Δ9-tetrahydrocannabinol component. This review article synthesises the current literature surrounding the modulation of the endocannabinoid system and administration of exocannabinoids in experimental and human IBD. Findings of clinical surveys and studies of cannabis use in IBD are summarised. Discrepancies in the literature are highlighted together with identifying novel areas of interest.

Endocannabinoids in the treatment of gasytrointestinal inflammation and symptoms

The evolving policies regarding the use of therapeutic Cannabis have steadily increased the public interest in its use as a complementary and alternative medicine in several disorders, including inflammatory bowel disease. Endocannabinoids represent both an appealing therapeutic strategy and a captivating scientific dilemma. Results from clinical trials have to be carefully interpreted owing to possible reporting-biases related to cannabinoids psychotropic effects. Moreover, discriminating between symptomatic improvement and the real gain on the underlying inflammatory process is often challenging. This review summarizes the advances and latest discovery in this ever-changing field of investigation, highlighting the main limitations in the current use of these drugs in clinical practice and the possible future perspectives to overcome these flaws.

Medical Cannabis and Cannabinoids: An Option for the Treatment of Inflammatory Bowel Disease and Cancer of the Colon?

In the past few years, we have witnessed a surge of new reports dealing with the role of cannabinoids, synthetic as well as herbal, in the mechanisms of inflammation and carcinogenesis. However, despite the wealth of in vitro data and anecdotal reports, evidence that cannabinoids could act as beneficial drugs in inflammatory bowel disease (IBD) or in neoplastic development of the human gastrointestinal tract is lacking. Some insight into the effects of medical Cannabis (usually meaning dried flowers) and cannabinoids in IBD has been gained through questionnaires and small pilot studies. As to colorectal cancer, only preclinical data are available. Currently, Δ⁹-tetrahydrocannabinol (THC) and its synthetic forms, dronabinol and nabilone, are used as an add-on treatment to alleviate chronic pain and spasticity in multiple sclerosis patients as well as chemotherapy-induced nausea. The use of medical Cannabis is authorized only in a limited number of countries. None of the mentioned substances are currently indicated for IBD. This review is an update of our knowledge on the role of cannabinoids in intestinal inflammation and carcinogenesis and a discussion on their potential therapeutic use.

Bioactive lipids ALIAmides differentially modulate inflammatory responses of distinct subsets of primary human T lymphocytes

Autacoid local injury antagonist amides (ALIAmides) are a family of endogenous bioactive acyl ethanolamides that include the renowned palmitoyl ethanolamide (PEA), oleoyl ethanolamide (OEA), and stearoyl ethanolamide (SEA), and that are involved in several biologic processes such as nociception, lipid metabolism, and inflammation. The role of ALIAmides in the control of inflammatory processes has recently gained much attention and prompted the use of these molecules or their analogs, and the pharmacologic manipulation of their endogenous levels, as plausible therapeutic strategies in the treatment of several chronic inflammatory conditions. Since chronic inflammation is mainly driven by cells of adaptive immunity, particularly T lymphocytes, we aimed at investigating whether such bioactive lipids could directly modulate T-cell responses. We found that OEA, PEA, and eicosatrienoyl ethanolamide (ETEA) could directly inhibit both T-cell responses by reducing their production of TNF-α and IFN-γ from CD8 T cells and TNF-α, IFN-γ and IL-17 from CD4 T cells. Furthermore, neither SEA nor docosatrienoyl ethanolamide (DTEA) could affect cytokine production from both T cell subsets. Interestingly, unlike OEA and ETEA, PEA was also able to enhance de novo generation of forkhead box P3 (FoxP3)-expressing regulatory T cells from CD4-naive T cells. Our findings show for the first time that specific ALIAmides can directly affect different T-cell subsets, and provide proof of their anti-inflammatory role in chronic inflammation, ultimately suggesting that these bioactive lipids could offer novel tools for the management of T-cell dependent chronic inflammatory diseases.-Chiurchiù, V., Leuti, A., Smoum, R., Mechoulam, R., Maccarrone, M. Bioactive lipids ALIAmides differentially modulate inflammatory responses of distinct subsets of primary human T lymphocytes.

Palmitoylethanolamide as adjunctive therapy in major depressive disorder: A double-blind, randomized and placebo-controlled trial

BACKGROUND

Experimental studies provide evidence for antidepressant effects of Palmitoylethanolamide (PEA) in animal models of depression. We aimed to evaluate the efficacy and tolerability of PEA add-on therapy in treatment of patients with major depressive disorder (MDD).

METHODS

In a randomized double-blind, and placebo-controlled study, 58 patients with MDD (DSM-5) and Hamilton Depression Rating Scale (HAM-D) score ≥ 19 were randomized to receive either 600 mg twice daily Palmitoylethanolamide or placebo in addition to citalopram for six weeks. Patients were assessed using the HAM-D scale at baseline and weeks 2, 4, and 6.

RESULTS

Fifty-four individuals completed the trial. At week 2, patients in the PEA group demonstrated significantly greater reduction in HAM-D scores compared to the placebo group (8.30 ± 2.41 vs. 5.81 ± 3.57, P = .004). The PEA group also demonstrated significantly greater improvement in depressive symptoms [F (3, 156) = 3.35, P = .021] compared to the placebo group throughout the trial period. The patients in the PEA group experienced more response rate (≥ 50% reduction in the HAM-D score) than the placebo group (100% vs. 74% respectively, P = .01) at the end of the trial. Baseline parameters and frequency of side effects were not significantly different between the two groups.

LIMITATIONS

The population size in this study was small and the follow-up period was relatively short.

CONCLUSIONS

Palmitoylethanolamide adjunctive therapy to citalopram can effectively improve symptoms of patients (predominantly male gender) with major depressive disorder. PEA showed rapid-onset antidepressant effects which need further investigation.

Innovative Nanoparticles Enhance N-Palmitoylethanolamide Intraocular Delivery

Nanostructured lipid carriers (NLCs) loaded with palmitoylethanolamide (PEA) were formulated with the aim to enhance ocular bioavailability of PEA, particularly to the back of the eye. Technological characterization (e.g., size, charge) of NLC loaded with PEA formulation (PEA-NLC) was performed, and NLC morphology was characterized by electron microscopy. Ocular pharmacokinetic study, after topical administration of the formulation, was carried out in rabbit eye. Ultra-high performance liquid chromatography tandem mass spectrometry analysis was carried out to detect PEA levels in ocular tissues. Finally, the ocular tolerability of PEA-NLC formulation was assessed in rabbit eye. The novel formulation significantly increased PEA levels in ocular tissues compared to PEA suspension. Vitreous and retinal levels of PEA were significantly higher in the group treated with PEA-NLC formulation versus PEA suspension (PEA-NLC C_max 5919 ± 541 pmol/g and 315 ± 70 pmol/g in vitreous and retina, respectively). The PEA-NLC formulation was characterized by high stability and robust ocular bioavailability. Therefore, this innovative formulation may be useful in clinical practice to manage retinal diseases.

HIV-1 Tat-induced diarrhea is improved by the PPARalpha agonist, palmitoylethanolamide, by suppressing the activation of enteric glia

Background

Diarrhea is a severe complication in HIV-1-infected patients with Trans-activator of transcription (HIV-1 Tat) protein being recognized as a major underlying cause. Beside its direct enterotoxic effects, Tat protein has been recently shown to affect enteric glial cell (EGC) activity. EGCs regulate intestinal inflammatory responses by secreting pro-inflammatory molecules; nonetheless, they might also release immune-regulatory factors, as palmytoilethanolamide (PEA), which exerts anti-inflammatory effects by activating PPARα receptors. We aimed at clarifying whether EGCs are involved in HIV-1 Tat-induced diarrhea and if PEA exerts antidiarrheal activity.

Methods

Diarrhea was induced by intracolonic administration of HIV-1 Tat protein in rats at day 1. PEA alone or in the presence of peroxisome proliferator-activated receptor (PPAR) antagonists was given intraperitoneally from day 2 to day 7. S100B, iNOS, NF-kappaB, TLR4 and GFAP expression were evaluated in submucosal plexi, while S100B and NO levels were measured in EGC submucosal plexi lysates, respectively. To verify whether PEA effects were PPARα-mediated, PPARα^−/− mice were also used. After 7 days from diarrhea induction, endogenous PEA levels were measured in submucosal plexi homogenates deriving from rats and PPARα^−/− mice.

Results

HIV-1 Tat protein induced rapid onset diarrhea alongside with a significant activation of EGCs. Tat administration significantly increased all hallmarks of neuroinflammation by triggering TLR4 and NF-kappaB activation and S100B and iNOS expression. Endogenous PEA levels were increased following HIV-1 Tat exposure in both wildtype and knockout animals. In PPARα^−/− mice, PEA displayed no effects. In wildtype rats, PEA, via PPARα-dependent mechanism, resulted in a significant antidiarrheal activity in parallel with marked reduction of EGC-sustained neuroinflammation.

Conclusions

EGCs mediate HIV-1 Tat-induced diarrhea by sustaining the intestinal neuroinflammatory response. These effects are regulated by PEA through a selective PPARα-dependent mechanism. PEA might be considered as an adjuvant therapy in HIV-1-induced diarrhea.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1126-4) contains supplementary material, which is available to authorized users.

The Use of Cannabinoids in Colitis: A Systematic Review and Meta-Analysis

BACKGROUND

Clinical trials investigating the use of cannabinoid drugs for the treatment of intestinal inflammation are anticipated secondary to preclinical literature demonstrating efficacy in reducing inflammation.

METHODS

We systematically reviewed publications on the benefit of drugs targeting the endo-cannabinoid system in intestinal inflammation. We collated studies examining outcomes for meta-analysis from EMBASE, MEDLINE and Pubmed until March 2017. Quality was assessed according to mSTAIR and SRYCLE score.

RESULTS

From 2008 papers, 51 publications examining the effect of cannabinoid compounds on murine colitis and 2 clinical studies were identified. Twenty-four compounds were assessed across 71 endpoints. Cannabidiol, a phytocannabinoid, was the most investigated drug. Macroscopic colitis severity (disease activity index [DAI]) and myeloperoxidase activity (MPO) were assessed throughout publications and were meta-analyzed using random effects models. Cannabinoids reduced DAI in comparison with the vehicle (standard mean difference [SMD] -1.36; 95% CI, -1.62 to-1.09; I2 = 61%). FAAH inhibitor URB597 had the largest effect size (SMD -4.43; 95% CI, -6.32 to -2.55), followed by the synthetic drug AM1241 (SMD -3.11; 95% CI, -5.01 to -1.22) and the endocannabinoid anandamide (SMD -3.03; 95% CI, -4.89 to -1.17; I2 not assessed). Cannabinoids reduced MPO in rodents compared to the vehicle; SMD -1.26; 95% CI, -1.54 to -0.97; I2 = 48.1%. Cannabigerol had the largest effect size (SMD -6.20; 95% CI, -9.90 to -2.50), followed by the synthetic CB1 agonist ACEA (SMD -3.15; 95% CI, -4.75 to -1.55) and synthetic CB1/2 agonist WIN55,212-2 (SMD -1.74; 95% CI, -2.81 to -0.67; I2 = 57%). We found no evidence of reporting bias. No significant difference was found between the prophylactic and therapeutic use of cannabinoid drugs.

CONCLUSIONS

There is abundant preclinical literature demonstrating the anti-inflammatory effects of cannabinoid drugs in inflammation of the gut. Larger randomised controlled-trials are warranted.

Chromogranin-A Regulates Macrophage Function and the Apoptotic Pathway in Murine DSS colitis

Chromogranin-A (CHGA) is elevated in inflammatory bowel disease (IBD), but little is known about its role in colonic inflammation. IBD is associated with impaired functions of macrophages and increased apoptosis of intestinal epithelial cells. We investigated CHGA expression in human subjects with active ulcerative colitis (UC) and the underlying mechanisms in Chga ^-/- mice. In UC, CHGA, classically activated macrophage (M1) markers, caspase-3, p53, and its associated genes were increased, while alternatively activated macrophage (M2) markers were decreased without changes in the extrinsic apoptotic pathway. CHGA correlated positively with M1 and the apoptotic pathway and negatively with M2. In the murine dextran sulfate sodium (DSS)-induced colitis, Chga deletion reduced the disease severity and onset, pro-inflammatory mediators, M1, and p53/caspase-3 activation, while it upregulated anti-inflammatory cytokines and M2 markers with no changes in the extrinsic apoptotic markers. Compared to Chga ^+/+ , M1 and p53/caspase-3 activation in Chga ^-/- macrophages were decreased in vitro, while M2 markers were increased. CHGA plays a critical role during colitis through the modulation of macrophage functions via the caspase-3/p53 pathway. Strategies targeting CHGA to regulate macrophage activation and apoptosis might be developed to treat UC patients.

KEY MESSAGES

• Chromogranin-A (CHGA) is pro-hormone and is secreted in the gut. CHGA is elevated in colitis and is associated with the disease severity. The lack of GHGA has beneficial immunomodulatory properties during the development of intestinal inflammation. The lack of CHGA regulates the plasticity of macrophages and p53/caspase activation in colitis. Functional analysis of CHGA may lead to a novel therapy for IBD.

Peroxisome Proliferator-Activated Receptor Modulation during Metabolic Diseases and Cancers: Master and Minions

The prevalence of obesity and metabolic diseases (such as type 2 diabetes mellitus, dyslipidaemia, and cardiovascular diseases) has increased in the last decade, in both industrialized and developing countries. This also coincided with our observation of a similar increase in the prevalence of cancers. The aetiology of these diseases is very complex and involves genetic, nutritional, and environmental factors. Much evidence indicates the central role undertaken by peroxisome proliferator-activated receptors (PPARs) in the development of these disorders. Due to the fact that their ligands could become crucial in future target-therapies, PPARs have therefore become the focal point of much research. Based on this evidence, this narrative review was written with the purpose of outlining the effects of PPARs, their actions, and their prospective uses in metabolic diseases and cancers.

The pharmacology of palmitoylethanolamide and first data on the therapeutic efficacy of some of its new formulations

Palmitoylethanolamide (PEA) has emerged as a potential nutraceutical, because this compound is naturally produced in many plant and animal food sources, as well as in cells and tissues of mammals, and endowed with important neuroprotective, anti-inflammatory and analgesic actions. Several efforts have been made to identify the molecular mechanism of action of PEA and explain its multiple effects both in the central and the peripheral nervous system. Here, we provide an overview of the pharmacology, efficacy and safety of PEA in neurodegenerative disorders, pain perception and inflammatory diseases. The current knowledge of new formulations of PEA with smaller particle size (i.e. micronized and ultra-micronized) when given alone or in combination with antioxidant flavonoids (i.e. luteolin) and stilbenes (i.e. polydatin) is also reviewed.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.