Acai berry extract as a regulator of intestinal inflammation pathways in a Caco-2 and RAW 264.7 co-culture model

Gut Microbiota-Derived Trimethylamine Promotes Inflammation with a Potential Impact on Epigenetic and Mitochondrial Homeostasis in Caco-2 Cells

Trimethylamine (TMA), a byproduct of gut microbiota metabolism from dietary precursors, is not only the precursor of trimethylamine-N-oxide (TMAO) but may also affect gut health. An in vitro model of intestinal epithelium of Caco-2 cells was used to evaluate the impact of TMA on inflammation, paracellular permeability, epigenetics and mitochondrial functions. The expression levels of pro-inflammatory cytokines (IL-6, IL-1β) increased significantly after 24 h exposure to TMA 1 mM. TMA exposure was associated with an upregulation of SIRT1 (TMA 1 mM, 400 μM, 10 μM) and DNMT1 (TMA 1 mM, 400 µM) genes, while DNMT3A expression decreased (TMA 1 mM). In a cell-free model, TMA (from 0.1 µM to 1 mM) induced a dose-dependent reduction in Sirtuin enzyme activity. In Caco-2 cells, TMA reduced total ATP levels and significantly downregulated ND6 expression (TMA 1 mM). TMA excess (1 mM) reduced intracellular mitochondrial DNA copy numbers and increased the methylation of the light-strand promoter in the D-loop area of mtDNA. Also, TMA (1 mM, 400 µM, 10 µM) increased the permeability of Caco-2 epithelium, as evidenced by the reduced transepithelial electrical resistance values. Based on our preliminary results, TMA excess might promote inflammation in intestinal cells and disturb epigenetic and mitochondrial homeostasis.

Gallic acid mitigates intestinal inflammation and loss of tight junction protein expression using a 2D-Caco-2 and RAW 264.7 co-culture model

A 2D-intestinal epithelial Caco-2/RAW 264.7 macrophage co-culture model was developed to demonstrate the relative efficacy of different phenolic acids to mitigate changes in Caco-2 epithelial cell redox state initiated both directly by autoxidation products, H2O2, and indirectly through cell communication events originating from cytokine stimulated macrophage. An inducer cocktail (lipopolysaccharide + interferon gamma) was used to activate RAW 264.7 cells in the 2D- Caco-2/RAW co-culture and intracellular changes in Caco-2 cell redox signaling occurred in response to positive changes (p < 0.05) in inflammatory biomarkers derived in macrophage that included IL-6, TNF-α, nitric oxide and peroxynitrite, respectively. Phenolic acids varied in relative capacity to reduce NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) in cocktail inflamed induced macrophage. This response in addition to the relative predisposition of gallic acid (GA) to undergo autoxidation to generate H2O2 activity (p < 0.05), culminated in downstream cell signaling in Caco-2 nuclear factor erythroid 2-related factor (Nrf2) activity (increase 26.9 %), altered monolayer integrity (increase 33.7 %), and release of interleukin 8 (IL-8) (decrease 80.5 %) (p < 0.05). It can be concluded that the co-culture model described herein was useful to assess the importance of communication between cytokine stimulated macrophage and intestinal cells. Moreover, the relative unique efficacy of GA, compared to other phenolic acids tested to protect against activated macrophage induced changes related to intestinal dysfunction were particularly relevant to epithelial redox signaling, intestinal permeability and regulation of tight junction proteins. This study concludes that phenolic acids are not equal in the capacity to protect against intestinal cell dysfunction despite some indication of biological activity.

An overview on the cellular mechanisms of anthocyanins in maintaining intestinal integrity and function

Structural and functional changes of the intestinal barrier, as a consequence of a number of (epi)genetic and environmental causes, have a main role in penetrations of pathogens and toxic agents, and lead to the development of inflammation-related pathological conditions, not only at the level of the GI tract but also in other extra-digestive tissues and organs. Anthocyanins (ACNs), a subclass of polyphenols belonging to the flavonoid group, are well known for their health-promoting properties and are widely distributed in the human diet. There is large evidence about the correlation between the human intake of ACN-rich products and a reduction of intestinal inflammation and dysfunction. Our review describes the more recent advances in the knowledge of cellular and molecular mechanisms through which ACNs can modulate the main mechanisms involved in intestinal dysfunction and inflammation, in particular the inhibition of the NF-κB, JNK, MAPK, STAT3, and TLR4 proinflammatory pathways, the upregulation of the Nrf2 transcription factor and the expression of tight junction proteins and mucins.

The Role of Anthocyanins in Alleviating Intestinal Diseases: A Mini Review

Anthocyanins are phytonutrients with physiological activity belonging to the flavonoid family whose transport and absorption in the human body follow specific pathways. In the upper gastrointestinal tract, anthocyanins are rarely absorbed intact by active transporters, with most reaching the colon, where bacteria convert them into metabolites. There is mounting evidence that anthocyanins can be used for prevention and treatment of intestinal diseases, including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and colorectal cancer (CRC), through the protective function on the intestinal epithelial barrier, immunomodulation, antioxidants, and gut microbiota metabolism. Dietary anthocyanins are summarized in this comprehensive review with respect to their classification and structure as well as their absorption and transport mechanisms within the gastrointestinal tract. Additionally, the review delves into the role and mechanism of anthocyanins in treating common intestinal diseases. These insights will deepen our understanding of the potential benefits of natural anthocyanins for intestinal disorders.

Natural Products as Dietary Agents for the Prevention and Mitigation of Oxidative Damage and Inflammation in the Intestinal Barrier

Food intake is a basic need to sustain life, but foodborne pathogens and food-related xenobiotics are also the main health concerns regarding intestinal barrier homeostasis. With a predominant role in the well-being of the entire human body, intestinal barrier homeostasis is strictly regulated by epithelial and immune cells. These cells are also the main intervenients in oxidative stress and inflammation-related diseases in the intestinal tract, triggered, for example, by genetic/epigenetic factors, food additives, pesticides, drugs, pathogens, and their metabolites. Nevertheless, the human diet can also be seen as a solution for the problem, mainly via the inclusion of functional foods or nutraceuticals that may act as antioxidant/anti-inflammatory agents to prevent and mitigate acute and chronic oxidative damage and inflammation. A literature analysis of recent advances in this topic highlights the significant role of Nrf2 (nuclear factor erythroid 2-related factor 2) and NF-kB (nuclear factor kappa-light-chain-enhancer of activated B cells) pathways in these biological processes, with many natural products and phytochemicals targeting endogenous antioxidant systems and cytokine production and balance. In this review, we summarized and discussed studies using in vitro and in vivo models of the intestinal tract used to reproduce oxidative damage and inflammatory events, as well as the role of natural products as modulators of Nrf2 and NK-kB pathways.

Phloretin suppresses intestinal inflammation and maintained epithelial tight junction integrity by modulating cytokines secretion in in vitro model of gut inflammation

Ulcerative colitis is a type of inflammatory bowel disease which in long run can lead to colorectal cancer (CRC). Chronic inflammation can be a key factor for the occurrence of CRC thus mitigating an inflammation can be a preventive strategy for the occurrence of CRC. In this study we have explored the anti-inflammatory potential of phloretin, in in vitro gut inflammation model, developed by co-culture of Caco2 (intestinal epithelial) cells and RAW264.7 macrophages (immune cells). Phloretin is a dihydrochalcone present in apple, pear and strawberries. An anti-inflammatory effect of phloretin in reducing LPS induced inflammation and maintenance of transepithelial electric resistance (TEER) in Caco2 cells was examined. Paracellular permeability assay was performed using Lucifer yellow dye to evaluate the effect of phloretin in inhibiting gut leakiness caused by inflammatory mediators secreted by activated macrophages. Phloretin attenuated LPS induced nitric oxide levels, oxidative stress, depolarization of mitochondrial membrane potential in Caco2 cells as evidenced by reduction in reactive oxygen species (ROS), and enhancement of MMP, and decrease in inflammatory cytokines IL8, TNFα, IL1β and IL6. It exhibited anti-inflammatory activity by inhibiting the expression of NFκB, iNOS and Cox2. Phloretin maintained the epithelial integrity by regulating the expression of tight junction proteins ZO1, occludin, Claudin1 and JAM. Phloretin reduced LPS induced levels of Cox2 along with the reduction in Src expression which further regulated an expression of tight junction protein occludin. Phloretin in combination to sodium pyruvate exhibited potential anti-inflammatory activity via targeting NFkB signaling. Our findings paved a way to position phloretin as nutraceutical in preventing the occurrence of colitis and culmination of disease into colitis associated colorectal cancer.

Açaí berry ameliorates cognitive impairment by inhibiting NLRP3/ASC/CASP axis in STZ-induced diabetic neuropathy in mice

Diabetes complications such as diabetic peripheral neuropathy (DPN) are linked to morbidity and mortality. Peripheral nerve damages in DPN are accompanied by discomfort, weakness, and sensory loss. Some drugs may demonstrate their therapeutic promise by reducing neuroinflammation, but they have side effects. Based on these considerations, the objective of this study was to examine the beneficial properties of açaí berry in a mouse model of DPN generated by injection of streptozotocin (STZ). Açaí berry was given orally to diabetic and control mice every day beginning 2 wk after STZ injection. The animals were euthanized after 16 wk, and tissues from the spinal cord and sciatic nerve and urine were taken. Our findings showed that daily treatment of açaí berry at a dose of 500 mg/kg was able to prevent behavioral changes as well as mast cell activation and nerve deterioration via NOD-like receptor family pyrin-domain-containing-3 (NLRP3)/apoptosis-associated speck-like protein containing a card (ASC)/caspase (CASP) regulation after diabetes induction.NEW & NOTEWORTHY Our research shows that açaí berry reduces mast cells degranulation and histological damage in diabetic neuropathy, improves physiological defense against reactive oxygen species, modulates the NLRP3/ASC/CASP axis, and ameliorates inflammation and oxidative stress. Diet could help treatment for diabetic peripheral neuropathy.

Carboxymethyl Cellulose as a Food Emulsifier: Are Its Days Numbered?

Carboxymethyl cellulose use in industry is ubiquitous. Though it is recognized as safe by the EFSA and FDA, newer works have raised concerns related to its safety, as in vivo studies showed evidence of gut dysbiosis associated with CMC's presence. Herein lies the question, is CMC a gut pro-inflammatory compound? As no work addressed this question, we sought to understand whether CMC was pro-inflammatory through the immunomodulation of GI tract epithelial cells. The results showed that while CMC was not cytotoxic up to 25 mg/mL towards Caco-2, HT29-MTX and Hep G2 cells, it had an overall pro-inflammatory behavior. In a Caco-2 monolayer, CMC by itself increased IL-6, IL-8 and TNF-α secretion, with the latter increasing by 1924%, and with these increases being 9.7 times superior to the one obtained for the IL-1β pro-inflammation control. In co-culture models, an increase in secretion in the apical side, particularly for IL-6 (692% increase), was observed, and when RAW 264.7 was added, data showed a more complex scenario as stimulation of pro-inflammatory (IL-6, MCP-1 and TNF-α) and anti-inflammatory (IL-10 and IFN-β) cytokines in the basal side was observed. Considering these results, CMC may exert a pro-inflammatory effect in the intestinal lumen, and despite more studies being required, the incorporation of CMC in foodstuffs must be carefully considered in the future to minimize potential GI tract dysbiosis.

Complex Interplay between Autophagy and Oxidative Stress in the Development of Endometriosis

Endometriosis (Endo) is a chronic gynecological disease. This paper aimed to evaluate the modulation of autophagy, oxidative stress and apoptosis with Açai Berries in a rat model of endometriosis. Endometriosis was induced with an intraperitoneal injection of minced uterus tissue from a donor rat into a recipient one. The abdominal high-frequency ultrasound (hfUS) analysis was performed at 7 and 14 days from the endometriosis induction to evaluate the growth of the lesion during the experiment. Seven days from the induction, once the lesions were implanted, an Açai Berry was administered daily by gavage for the next seven days. At the end of the experiment, the hfUS analysis showed a reduced lesion diameter in animals given the Açai Berry. A macroscopical and histological analysis confirmed this result. From the molecular point of view, Western blot analyses were conducted to evaluate the autophagy induction. Samples collected from the Endo group showed impaired autophagy, while the Açai Berry administration inhibited PI3K and AKT and ERK1/2 phosphorylation and promoted autophagy by inactivating mTOR. Additionally, Açai Berry administration dephosphorylated ATG1, promoting the activity of the ATG1/ULK1 complex that recruited Ambra1/Beclin1 and Atg9 to promote autophagosome nucleation and LC3II expression. Açai Berry administration also restored mitophagy, which increased Parkin cytosolic expression. The Açai Berry increased the expression of NRF2 in the nucleus and the expression of its downstream antioxidant proteins as NQO-1 and HO-1, thereby restoring the oxidative imbalance. It also restored the impaired apoptotic pathway by reducing BCL-2 and increasing BAX expression. This result was also confirmed by the TUNEL assay. Overall, our results displayed that Açai Berry administration was able to modulate autophagy, oxidative stress and apoptosis during endometriosis.

Açai Berry Attenuates Cyclophosphamide-Induced Damage in Genitourinary Axis-Modulating Nrf-2/HO-1 Pathways

Cyclophosphamide (CYP) is used to treat different malignancies and autoimmune disorders in men. This chemotherapy frequently reduces tumors, which is beneficial, but also causes infertility because of severe oxidative stress, inflammation, and apoptosis in the bladder and testes brought on by its metabolite, acrolein. The goal of this study was to assess the efficacy of a novel food, açai berry, in preventing CYP-induced damage in the bladder and testes.

METHODS

CYP was administered intraperitoneally once during the experiment at a dose of 200 mg/kg body weight diluted in 10 mL/kg b.w. of water. Açai berry was administered orally at a dose of 500 mg/kg.

RESULTS

The administration of açai berry was able to reduce inflammation, oxidative stress, lipid peroxidation, apoptosis, and histological changes in the bladder and testes after CYP injection.

CONCLUSIONS

Our findings show for the first time that açai berry modulates physiological antioxidant defenses to protect the bladder and testes against CYP-induced changes.

Methylation, Hydroxylation, Glycosylation and Acylation Affect the Transport of Wine Anthocyanins in Caco-2 Cells

Anthocyanins are substances with multiple physiological activities widely present in red wine, but the influence of structure (methylation, hydroxylation, acylation, glycosylation) on the transport remains ill-defined. In the present study, Caco-2 monolayers were used as an in vitro model of the absorptive intestinal epithelium to transport different types of anthocyanin samples. Results showed that both methylation and acetylation promote the level of transport. Monoglycoside standard exhibited higher transport amount and rate compared to diglycoside standard while the transport level of the monoglycoside mixture was unexpectedly lower than that of the diglycoside mixture. Caco-2 monolayers appeared to be more capable of transporting the single standard than the mixed standard. Meanwhile, the transport of anthocyanins in Caco-2 cell model showed time- and concentration-dependent trends. Anthocyanin treatment had a greater effect on sodium-dependent glucose transporter 1 (SGLT1) mRNA expression than glucose transporter 2 (GLUT2), and significantly down-regulated the protein expression of SGLT1. Although the low bioavailability of anthocyanins requires much more research, further evidence of the role of structure is provided.

Cellular uptake, transport mechanism and anti-inflammatory effect of cyanidin-3-glucoside nanoliposomes in Caco-2/RAW 264.7 co-culture model

Cyanidin-3-glucoside (C3G), which is the widest and richest anthocyanin (ACN) found in the edible fruit and vegetables, has been illustrated to perform a wide range of bioactivities. Nanoliposomes can inhibit C3G degradation and enhance the absorption rate of C3G as tools for conveying materials to particular locations. This experiment aims to study the absorption, transport and anti-inflammatory effects of C3G nanoliposomes in Caco-2/RAW 264.7 co-culture model, which symbolizes an intestinal inflammation system. The results indicated that the uptake and transport of C3G nanoliposomes by Caco-2/RAW 264.7 co-culture model were concentration-dependent as well as affected by temperature (37 and 4°C) and endocytic inhibitors, which revealed C3G nanoliposomes penetrate cells via endocytosis. Moreover, compared with C3G, C3G nanoliposomes significantly decreased pro-inflammatory cytokine expression (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8), suggesting a stronger anti-inflammatory potential. Conclusively, the uptake of C3G nanoliposomes by Caco-2/RAW 264.7 co-culture model is mainly involved in macropinocytosis and endocytosis mediated by carrier protein (clathrin). C3G nanoliposomes may play a better role in the treatment of LPS-induced intestinal inflammation diseases.

Açai Berry Mitigates Vascular Dementia-Induced Neuropathological Alterations Modulating Nrf-2/Beclin1 Pathways

The second-most common cause of dementia is vascular dementia (VaD). The majority of VaD patients experience cognitive impairment, which is brought on by oxidative stress and changes in autophagic function, which ultimately result in neuronal impairment and death. In this study, we examine a novel method for reversing VaD-induced changes brought on by açai berry supplementation in a VaD mouse model. The purpose of this study was to examine the impact of açai berries on the molecular mechanisms underlying VaD in a mouse model of the disease that was created by repeated ischemia-reperfusion (IR) of the whole bilateral carotid artery. Here, we found that açai berry was able to reduce VaD-induced behavioral alteration, as well as hippocampal death, in CA1 and CA3 regions. These effects are probably due to the modulation of nuclear factor erythroid 2-related factor 2 (Nrf-2) and Beclin-1, suggesting a possible crosstalk between these molecular pathways. In conclusion, the protective effects of açai berry could be a good supplementation in the future for the management of vascular dementia.