Moluodan promotes DSS-induced intestinal inflammation involving the reprogram of macrophage function and polarization

ETHNOPHARMACOLOGICAL RELEVANCE

Moluodan (MLD) is a traditional Chinese medicine that is composed of 18 herbal medicines based on traditional Chinese medicine theory and practice. It has long been used in treating chronic gastritis and its components were traditionally used in dealing with intestinal inflammation. However, its specific pharmacological mechanism is still unclear.

AIM OF THE STUDY

The upper and lower digestive tract diseases are correlated. In clinical practice, some chronic gastritis patients are also accompanied by intestinal inflammation. Due to the unclear pharmacological mechanism of MLD and its effect on intestinal inflammation, there is doubt whether MLD is still suitable for this type of patient. Therefore, this study aims to elucidate the pharmacological mechanism of MLD and identify its effect in the mouse model of intestinal inflammation.

MATERIALS AND METHODS

Mice intestinal inflammation model was induced by 2.5% dextran sulfate sodium (DSS). The mice were given different concentrations of MLD via oral gavage (0.25, 0.5 g/kg b.w.). Pharmacodynamic indicators were assessed including body weight, colon length, disease activity index (DAI), bloody stool score, inflammatory factors, histological change, etc. RAW264.7 macrophage cells were used for in vitro experiments that illuminated the role of MLD in reprogramming macrophage function and polarization. RT-qPCR and western blots were performed to measure the mRNA and protein levels of macrophage polarization marker and effector molecules. The functions of polarized macrophages were tested using ROS detection probes, Edu assay and wound healing assay.

RESULTS

The administration of MLD exhibited obvious hemostatic effects, while unexpectedly accentuating various aspects of the DSS-induced intestinal inflammation in mice, including increased body weight loss and colon shortening, elevated disease activity index, and intensified colonic tissue damage. Additionally, MLD treatment induced more severe inflammatory cell infiltration and higher proinflammatory cytokines expression in colon tissue. Further results showed that MLD promoted M1 macrophage polarization and stimulated its proinflammatory cytokines expression, while only slightly affecting the function of M2 macrophage. Western blot analysis revealed that MLD induced the phosphorylation of AKT and NF-κB. The polarization of M1 macrophages induced by MLD was inhibited by either an Akt inhibitor or a NF-κB inhibitor.

CONCLUSIONS

Although MLD has an obvious hemostatic effect, it generally promoted the severity of DSS-induced colitis in mice by facilitating macrophage polarization toward the M1 phenotype through the AKT/NF-κB pathway. Our study suggested that MLD may not be suitable for colitis, especially during the acute inflammation stage.

Xiao-Ban-Xia decoction mitigates cisplatin-induced emesis via restoring PINK1/Parkin mediated mitophagy deficiency in a rat pica model

ETHNOPHARMACOLOGICAL RELEVANCE

As a traditional Chinese anti-emetic formula, Xiao-Ban-Xia decoction (XBXD) was recorded in Golden Chamber, and has promising anti-emetic effect on chemotherapy-induced nausea and vomiting (CINV).

AIM OF THE STUDY

This study aimed to determine whether the underlying mechanism of XBXD against CINV is correlated to the restoration of cisplatin-induced PINK1/Parkin mediated mitophagy deficiency and mitigation of gastrointestinal inflammation.

MATERIALS AND METHODS

The rat pica model was established by intraperitoneal injection of cisplatin 6 mg/kg. The daily kaolin consumption, food intake and body weight were recorded every 24 h. The pathological damage of gastric antrum and ileum were observed by hematoxylin-eosin staining. The levels of serum reactive oxygen species (ROS), interleukin-1β (IL-1β) and interleukin-1β (IL-18) were detected by ELISA. The expression of microtubule-associated protein 1 light chain 3 (LC3) in gastric antrum and ileum was detected by Immunofluorescence staining. The levels of LC3II, P62/SQSTM1, PTEN-induced putative protein kinases (PINK1), E3 ubiquitin ligase (Parkin), AMP-dependent protein kinases (AMPK), phosphorylated AMPK (p-AMPK), nuclear factor erythroid 2-related factor (Nrf2) and kelch like ECH Associated Protein 1 (Keap1) in gastric antrum and ileum were assayed by western blotting.

RESULTS

At 24 h and 72 h following cisplatin challenge, XBXD inhibited cisplatin-induced elevation of kaolin consumption, and improved the daily food intake and body weight loss in rats. Cisplatin-induced gastrointestinal histopathological damages were alleviated, and serum levels of ROS, IL-1β and IL-18 increases were mitigated following XBXD treatments. In gastric antrum and ileum, XBXD activated AMPK-Nrf2 signaling pathway and restored cisplatin-induced PINK1/Parkin mediated mitophagy deficiency.

CONCLUSIONS

XBXD significantly ameliorated CINV in a cisplatin-induced rat pica model. The underlying anti-emetic mechanism of XBXD might be related to the activation of AMPK-Nrf2 signaling pathway and the restoration of cisplatin-induced PINK1/Parkin-mediated mitophagy deficiency in the gastrointestinal tract.

Xiaobanxia decoction alleviates chemotherapy-induced nausea and vomiting by inhibiting GSDME-mediated pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaobanxia Decoction (XBXD), a traditional antiemetic formula, is effective in preventing chemotherapy-induced nausea and vomiting (CINV), but its underlying mechanism has not been fully clarified.

AIM OF THE STUDY

To investigate whether the antiemetic mechanisms of XBXD against CINV is associated with the reduction of GSDME-mediated pyroptosis and the alleviation of gastrointestinal inflammation induced by cisplatin.

MATERIALS AND METHODS

We established the in vivo pica rat model and the in vitro small intestinal epithelial cell (IEC-6 cell) injury model by cisplatin challenge. The levels of ROS, IL-1β, IL-18, HMGB1 were measured by ELISA. The histopathological changes of gastrointestinal (GI) tissues were examined by HE staining. The expression and localization of GSDME in GI tissues were determined by IHC. The GSDME mRNA expression in GI tissues was determined by RT-PCR. The IEC-6 cell viability was detected by CCK-8. The morphology of IEC-6 cells was observed by optical microscope and scanning electron microscopy. Pyroptosis was examined using Hoechst33342/PI staining. The intracellular ROS levels were measured with the fluorescent probe DCFH-DA. The expression levels of JNK, p-JNK, Bax, Bcl-2, caspase-9, caspase-3 and GSDME in GI tissues and IEC-6 cells were determined by WB.

RESULTS

We found that the cumulative kaolin intake (pica behavior, analogous to emesis) significantly increased in cisplatin-treated rats, accompanied by significant inflammatory pathological changes of GI tissues. XBXD decreased the cumulative kaolin intake and alleviated GI inflammation in cisplatin-treated rats by inhibiting the activation of the ROS/JNK/Bax signaling pathway and by reducing GSDME-mediated pyroptosis. Additionally, cisplatin damaged IEC-6 cells by activating GSDME-dependent pyroptosis. XBXD reduced GSDME-mediated IEC-6 cell pyroptotic death by regulating the ROS/JNK/Bax signaling pathway.

CONCLUSIONS

This study suggested that GSDME-mediated pyroptosis greatly contributes to the occurrence of CINV, and suppressing GSDME-mediated pyroptosis is the important antiemetic mechanism of XBXD.

The multiple roles of dopamine receptor activation in the modulation of gastrointestinal motility and mucosal function

Dopamine (DA) is a catecholamine regulatory molecule with potential role in physiology and physiopathology of the intestinal tract. Various cellular sources of DA have been indicated as enteric neurons, immune cells, intestinal flora and gastrointestinal epithelium. Moreover, DA is produced by nutritional tyrosine. All the five DA receptors, actually described, are present throughout the gut. Current knowledge of DA in this area is reviewed, focusing on gastrointestinal function in health and during inflammation. Research on animal models and humans are reported. A major obstacle to understanding the physiologic and/or pharmacological roles of enteric DA is represented by the multiplicity of receptors involved in the responses together with many signalling pathways related to each receptor subtype. It is mandatory to map precisely the distributions of DA receptors, to determine the relevance of a receptor in a specific location in order to explore novel therapies directed to dopaminergic targets that may be useful in the control of intestinal inflammation.

Gastrointestinal consequences of lipopolysaccharide-induced lung inflammation

BACKGROUND

Respiratory inflammation is the body's response to lung infection, trauma or hypersensitivity and is often accompanied by comorbidities, including gastrointestinal (GI) symptoms. Why respiratory inflammation is accompanied by GI dysfunction remains unclear. Here, we investigate the effect of lipopolysaccharide (LPS)-induced lung inflammation on intestinal barrier integrity, tight-junctions, enteric neurons and inflammatory marker expression.

METHODS

Female C57bl/6 mice (6-8 weeks) were intratracheally administered LPS (5 µg) or sterile saline, and assessed after either 24 or 72 h. Total and differential cell counts in bronchoalveolar lavage fluid (BALF) were used to evaluate lung inflammation. Intestinal barrier integrity was assessed via cross sectional immunohistochemistry of tight junction markers claudin-1, claudin-4 and EpCAM. Changes in the enteric nervous system (ENS) and inflammation in the intestine were quantified immunohistochemically using neuronal markers Hu + and nNOS, glial markers GFAP and S100β and pan leukocyte marker CD45.

RESULTS

Intratracheal LPS significantly increased the number of neutrophils in BALF at 24 and 72 h. These changes were associated with an increase in CD45 + cells in the ileal mucosa at 24 and 72 h, increased goblet cell expression at 24 h, and increased expression of EpCAM at 72 h. LPS had no effect on the expression of GFAP, S100β, nor the number of Hu + neurons or proportion of nNOS neurons in the myenteric plexus.

CONCLUSIONS

Intratracheal LPS administration induces inflammation in the ileum that is associated with enhanced expression of EpCAM, decreased claudin-4 expression and increased goblet cell density, these changes may contribute to systemic inflammation that is known to accompany many inflammatory diseases of the lung.

Gut microenvironmental changes as a potential trigger in Parkinson's disease through the gut-brain axis

Parkinson's disease (PD) is the second most common neurodegenerative disease attributed to the synergistic effects of genetic risk and environmental stimuli. Although PD is characterized by motor dysfunction resulting from intraneuronal alpha-synuclein accumulations, termed Lewy bodies, and dopaminergic neuronal degeneration in the substantia nigra, multiple systems are involved in the disease process, resulting in heterogenous clinical presentation and progression. Genetic predisposition to PD regarding aberrant immune responses, abnormal protein aggregation, autophagolysosomal impairment, and mitochondrial dysfunction leads to vulnerable neurons that are sensitive to environmental triggers and, together, result in neuronal degeneration. Neuropathology studies have shown that, at least in some patients, Lewy bodies start from the enteric nervous system and then spread to the central dopaminergic neurons through the gut-brain axis, suggesting the contribution of an altered gut microenvironment in the pathogenesis of PD. A plethora of evidence has revealed different gut microbiomes and gut metabolites in patients with PD compared to unaffected controls. Chronic gut inflammation and impaired intestinal barrier integrity have been observed in human PD patients and mouse models of PD. These observations led to the hypothesis that an altered gut microenvironment is a potential trigger of the PD process in a genetically susceptible host. In this review, we will discuss the complex interplay between genetic factors and gut microenvironmental changes contributing to PD pathogenesis.

Efficacy of probiotics for managing infantile colic due to their anti-inflammatory properties: a meta-analysis and systematic review

BACKGROUND

Infantile colic (IC) is excessive crying in otherwise healthy children. Despite vast research efforts, its etiology remains unknown.

PURPOSE

Most treatments for IC carry various side effects. The collection of evidence may inform researchers of new strategies for the management and treatment of IC as well as new clues for understanding its pathogenesis. This review and meta-analysis aimed to evaluate the efficacy and possible mechanisms of probiotics for mananaging IC.

METHODS

Ten papers met the study inclusion and exclusion criteria, and the meta-analysis was conducted using Review Manager (RevMan) software and a random-effects model.

RESULTS

This meta-analysis revealed that probiotics are effective for treating infantile colic, while the review showed that this efficacy may be due to their anti-inflammatory effects.

CONCLUSION

Probiotics may be an important treatment option for managing infantile colic due to their anti-inflammatory properties.

Targeting ectonucleotidases to treat inflammation and halt cancer development in the gut

CD39 and CD73 control cell immunity by hydrolyzing proinflammatory ATP and ADP (CD39) into AMP, subsequently converted into anti-inflammatory adenosine (CD73). By regulating the balance between effector and regulatory cells, these ectonucleotidases promote immune homeostasis in acute and chronic inflammation; while also appearing to limit antitumor effector immunity in gut cancer. This manuscript focuses on the pivotal role of CD39 and CD73 ectonucleotidase function in shaping immune responses in the gut. We focus on those mechanisms deployed by these critical and pivotal ectoenzymes and the regulation in the setting of gastrointestinal tract infections, inflammatory bowel disease and tumors of the gastrointestinal tract. We will highlight translational and clinical implications of the latest and most innovative basic research discoveries of these important players of the purinergic signaling. Immunotherapeutic strategies that have been developed to either boost or control ectonucleotidase expression and activity in important disease settings are also reviewed and the in vivo effects discussed.

Routine panendoscopy in oral squamous cell cancer patients: mandatory or facultative?

Objectives

This study investigated benefits of routine panendoscopy in staging of oral squamous cell cancer patients.

Materials and methods

From 2013 to 2017, 194 oral squamous cell cancer patients were staged. Reports of routine flexible panendoscopy including oropharyngolaryngoscopy, bronchoscopy, and esophagogastroduodenoscopy were retrospectively analyzed for diagnoses of inflammation and second primary malignancies (carcinoma in situ or cancer) and compared to results of computed tomography. The effects of alcohol and tobacco history of 142 patients were assessed.

Results

Overall, a second primary malignancy was detected in seven patients. In four patients this discovery was only found by panendoscopy. One invasive carcinoma (esophagus) was detected as well as three carcinoma in situ. The second primary malignancies were located in the lung (3), esophagus (3), and stomach (1). In one patient index tumor therapy was modified after panendoscopy. Upper gastrointestinal inflammation was present in 73.2% of patients and 61.9% required treatment. About 91.8% of bronchoscopies and 34.5% of panendoscopies were without therapeutic consequences. Patients with higher risk from smoking were more likely to benefit from panendoscopy and to have a Helicobacter pylori infection.

Conclusion

We do not recommend routine panendoscopy for all oral squamous cell cancer patients. Esophagogastroduodenoscopy benefitted smoking patients primarily concerning the secondary diagnosis of inflammation of the upper digestive tract. Selective bronchoscopy, esophagogastroduodenoscopy, and oropharyngolaryngoscopy should be performed if clinical examination or medical history indicates risks for additional malignancies of the upper aerodigestive tract.

Clinical relevance

Routine panendoscopy is not recommended in all, especially not in low-risk oral cancer patients like non-smokers and non-drinkers.

Evaluation of immunologic and intestinal effects in rats administered an E 171-containing diet, a food grade titanium dioxide (TiO2)

The toxicity of dietary E 171, a food grade titanium dioxide was evaluated. A recent study reported rats receiving E 171 in water developed inflammation and aberrant crypt foci (ACF) in the gastrointestinal tract. Here, rats received food containing E 171 (7 or 100 days). The 100-day study included feeding E 171 after dimethylhydrazine (DMH) or vehicle only pretreatment. Food consumption was similar between treatment groups with maximum total cumulative E 171 exposure being 2617 mg/kg in 7 days and 29,400 mg/kg in 100 days. No differences were observed due to E 171 in the percentage of dendritic, CD4+ T or Treg cells within Peyer's patches or the periphery, or in cytokine production in plasma, sections of jejunum, and colon in 7- or 100-day E 171 alone fed rats. Differences were observed for IL-17A in colon (400 ppm E 171 + DMH) and IL-12p70 in plasma (40 ppm E 171 + DMH). E 171 had no effect on histopathologic evaluations of small and large intestines, liver, spleen, lungs, or testes, and no effects on ACF, goblet cell numbers, or colonic gland length. Dietary E 171 administration (7- or 100-day), even at high doses, produced no effect on the immune parameters or tissue morphology.

An antibiotic depleted microbiome drives severe Campylobacter jejuni-mediated Type 1/17 colitis, Type 2 autoimmunity and neurologic sequelae in a mouse model

The peripheral neuropathy Guillain-Barré Syndrome can follow Campylobacter jejuni infection when outer core lipooligosaccharides induce production of neurotoxic anti-ganglioside antibodies. We hypothesized that gut microbiota depletion with an antibiotic would increase C. jejuni colonization, severity of gastroenteritis, and GBS. Microbiota depletion increased C. jejuni colonization, invasion, and colitis with Type 1/17 T cells in gut lamina propria. It also stimulated Type 1/17 anti-C. jejuni and -antiganglioside-antibodies, Type 2 anti-C. jejuni and -antiganglioside antibodies, and neurologic phenotypes. Results indicate that both C. jejuni strain and gut microbiota affect development of inflammation and GBS and suggest that probiotics following C. jejuni infection may ameliorate inflammation and autoimmune disease.

Follow up on atopy and the gastrointestinal tract - a review of a common association 2018

Primary atopic disorders can be classified as heritable genetic disorders presenting with deregulated pathogenic allergic effector responses irrespective of sensitization. In the last decade, there are parallel rises in the burden of atopic and gastrointestinal (GI) diseases. Areas covered: There is increasing recognition of an association between atopy and GI disease through immune dysregulation, the microbiome and shared genetic pathways. Since the first article on atopy and the GI tract in 2014 in this journal, many more studies have shed light on the shared pathways in these diseases, particularly in the field of eosinophilic GI disease, functional GI disorders, and inflammatory bowel disease. Expert opinion: Understanding the links with common mechanisms in atopy and GI diseases that may lead to better targeting of treatment through manipulation of immune mechanisms, the microbiome, genetics, food allergens and specific GI diseases such as inflammatory bowel disease, functional GI disorders.

Overlap between functional abdominal pain disorders and organic diseases in children

Functional abdominal pain disorders are highly prevalent in children. These disorders can be present in isolation or combined with organic diseases, such as celiac disease and inflammatory bowel diseases. Intestinal inflammation (infectious and non-infectious) predisposes children to the development of visceral hypersensitivity that can manifest as functional abdominal pain disorders, including irritable bowel syndrome. The new onset of irritable bowel syndrome symptoms in a patient with an underlying organic disease, such as inflammatory bowel disease, is clinically challenging, given that the same symptomatology may represent a flare-up of the inflammatory bowel disease or an overlapping functional abdominal pain disorder. Similarly, irritable bowel syndrome symptoms in a child previously diagnosed with celiac disease may occur due to poorly controlled celiac disease or the overlap with a functional abdominal pain disorder. There is little research on the overlap of functional abdominal disorders with organic diseases in children. Studies suggest that the overlap between functional abdominal pain disorders and inflammatory bowel disease is more common in adults than in children. The causes for these differences in prevalence are unknown. Only a handful of studies have been published on the overlap between celiac disease and functional abdominal pain disorders in children. The present article provides a review of the literature on the overlap between celiac disease, inflammatory bowel disease, and functional abdominal pain disorders in children and establish comparisons with studies conducted on adults.

MicroRNA in gastrointestinal cell signalling

Our gut forms an important organ and its formation, functioning and homeostasis are maintained by several factors including cell signalling pathways and commensal microflora. These factors affect pathological, physiological and immunological parameters to maintain gut health and prevent its inflammation. Among these, different intracellular signalling pathways play an important role in regulating gut homeostasis. These pathways are in turn regulated by various microRNAs that play a key role in maintaining the balance between tolerance and inflammation. This review highlights the importance of various cell signalling pathways in modulating gut homeostasis and the role specific miRNAs play in their regulation.

Transplanted human fecal microbiota enhanced Guillain Barré syndrome autoantibody responses after Campylobacter jejuni infection in C57BL/6 mice

BACKGROUND

Campylobacter jejuni is the leading antecedent infection to the autoimmune neuropathy Guillain-Barré syndrome (GBS), which is accompanied by an autoimmune anti-ganglioside antibody attack on peripheral nerves. Previously, we showed that contrasting immune responses mediate C. jejuni induced colitis and autoimmunity in interleukin-10 (IL-10)-deficient mice, dependent upon the infecting strain. Strains from colitis patients elicited T helper 1 (T_H1)-dependent inflammatory responses while strains from GBS patients elicited T_H2-dependent autoantibody production. Both syndromes were exacerbated by antibiotic depletion of the microbiota, but other factors controlling susceptibility to GBS are unknown.

METHODS

Using 16S rRNA gene high-throughput sequencing, we examined whether structure of the gut microbial community alters host (1) gastrointestinal inflammation or (2) anti-ganglioside antibody responses after infection with C. jejuni strains from colitis or GBS patients. We compared these responses in C57BL/6 mice with either (1) stable human gut microbiota (^Humicrobiota) transplants or (2) conventional mouse microbiota (^Convmicrobiota).

RESULTS

Inoculating germ-free C57BL/6 wild-type (WT) mice with a mixed human fecal slurry provided a murine model that stably passed its microbiota over >20 generations. Mice were housed in specific pathogen-free (SPF) facilities, while extra precautions of having caretakers wear sterile garb along with limited access ensured that no mouse pathogens were acquired. ^Humicrobiota conferred many changes upon the WT model in contrast to previous results, which showed only colonization with no disease after C. jejuni challenge. When compared to ^Convmicrobiota mice for susceptibility to C. jejuni enteric or GBS patient strains, infected ^Humicrobiota mice had (1) 10-100 fold increases in C. jejuni colonization of both strains, (2) pathologic change in draining lymph nodes but only mild changes in colon or cecal lamina propria, (3) significantly lower Th1/Th17-dependent anti-C. jejuni responses, (4) significantly higher IL-4 responses at 5 but not 7 weeks post infection (PI), (5) significantly higher Th2-dependent anti-C. jejuni responses, and (6) significantly elevated anti-ganglioside autoantibodies after C. jejuni infection. These responses in ^Humicrobiota mice were correlated with a dominant Bacteroidetes and Firmicutes microbiota.

CONCLUSIONS

These data demonstrate that ^Humicrobiota altered host-pathogen interactions in infected mice, increasing colonization and Th-2 and autoimmune responses in a C. jejuni strain-dependent manner. Thus, microbiota composition is another factor controlling susceptibility to GBS.

Age-related levels of fecal M2-pyruvate kinase in children with cystic fibrosis and healthy children 0 to 10years old

BACKGROUND

The pathogenesis of gut inflammation, bacterial dysbiosis and increased rates of malignancy in CF is unclear. Fecal M2-pyruvate kinase (M2-PK) is a biomarker indicative of cellular proliferation that may be raised in intestinal malignancy and inflammation. Biomarkers, including M2-PK, may be useful in assessing effects of novel therapies on the gastrointestinal tract.

METHODS

M2-PK was measured in stools collected from patients with CF and HC (0-10years). Linear mixed model analysis was used.

RESULTS

M2-PK levels did not significantly change in children with CF (36 patients, 77 samples) (P=0.998) or HC (45 patients, 45 samples) (P=0.21), over the age range 0-10years. Patients with CF had elevated M2-PK compared to HC (median [IQR; range]: 10.7 [5.7-28.6; 1.0-239.1] (n=77) vs. 1.0 [1.0-1.0; 1.0-50.0] (n=45) U/mL, respectively; P=0.001).

CONCLUSIONS

Fecal M2-PK was elevated in children with CF compared with HC during infancy and throughout childhood suggesting abnormalities in the CF gut exist in early life.

Age-dependent variation of fecal calprotectin in cystic fibrosis and healthy children

BACKGROUND

Fecal calprotectin may be used as a non-invasive method to assess the effect of novel therapies on the gut in cystic fibrosis (CF).

METHOD

Stools from CF patients and healthy controls (HC) (0-10years old) were prospectively collected for evaluation of temporal trends.

RESULTS

130 CF samples (64 subjects) and 114 HC samples (101 subjects) were collected. Overall, fecal calprotectin levels were different in CF patients and HC from 0 to 10years (P=0.0002). Fecal calprotectin in CF was significantly lower than HC from 0 to 1years (P=0.03) and demonstrated an upward trajectory until 4years. From >4 to 10years calprotectin was consistently higher in CF patients compared with HC (P=0.007).

CONCLUSIONS

Fecal calprotectin levels in children with CF and HC were age-dependent and had distinct trajectories. Careful interpretation of calprotectin is required if used in drug trials for CF, particularly in children less than 4years old.

Non-invasive panel tests for gastrointestinal motility monitoring within the MARS-500 Project

AIM: To develop an integrated approach for monitoring gastrointestinal motility and inflammation state suitable for application in long-term spaceflights.

METHODS: Breath tests based on the oral administration of ¹³C-labeled or hydrogen-producing substrates followed by the detection of their metabolites (¹³CO₂ or H₂) in breath were used to measure gastrointestinal motility parameters during the 520-d spaceflight ground simulation within the MARS-500 Project. In particular, the gastric emptying rates of solid and liquid contents were evaluated by ¹³C-octanoic acid and ¹³C-acetate breath tests, respectively, whereas the orocecal transit time was assessed by an inulin H₂-breath test, which was performed simultaneously with the ¹³C-octanoic acid breath test. A ready-to-eat, standardized pre-packaged muffin containing 100 mg of ¹³C-octanoic acid was used in the ¹³C-octanoic acid breath test to avoid the extemporaneous preparation of solid meals. In addition, a cassette-type lateral flow immunoassay was employed to detect fecal calprotectin, a biomarker of intestinal inflammation. Because no items could be introduced into the simulator during the experiment, all materials and instrumentation required for test performance during the entire mission simulation had to be provided at the beginning of the experiment.

RESULTS: The experiments planned during the simulation of a manned flight to Mars could be successfully performed by the crewmembers without any external assistance. No evident alterations (i.e., increasing or decreasing trends) in the gastric emptying rates were detected using the ¹³C-breath tests during the mission simulation, as the gastric emptying half-times were in the range of those reported for healthy subjects. In contrast to the ¹³C-breath tests, the results of the inulin H₂-breath test were difficult to interpret because of the high variability of the H₂ concentration in the breath samples, even within the same subject. This variability suggested that the H₂-breath test was strongly affected by external factors, which may have been related to the diet of the crewmembers or to environmental conditions (e.g., the accumulation of hydrogen in the simulator microenvironment). At least in closed microenvironments such as the MARS-500 simulator, ¹³C-breath tests should therefore be preferred to H₂-breath tests. Finally, the fecal calprotectin test showed significant alterations during the mission simulation: all of the crewmembers were negative for the test at the beginning of the simulation but showed various degrees of positivity in at least one of the subsequent tests, thus indicating the onset of an intestinal inflammation.

CONCLUSION: Breath tests, especially those ¹³C-based, proved suitable for monitoring gastrointestinal motility in the 520-d isolation experiment within MARS-500 project and can be applied in long-term spaceflights.

Heme oxygenase-1 system and gastrointestinal inflammation: A short review

Heme oxygenase-1 (HO-1) system catalyzes heme to biologically active products: carbon monoxide, biliverdin/bilirubin and free iron. It is involved in maintaining cellular homeostasis and many physiological and pathophysiological processes. A growing body of evidence indicates that HO-1 activation may play an important protective role in acute and chronic inflammation of gastrointestinal tract. This review focuses on the current understanding of the physiological significance of HO-1 induction and its possible roles in the gastrointestinal inflammation studied to date. The ability to upregulate HO-1 by pharmacological means or using gene therapy may offer therapeutic strategies for gastrointestinal inflammation in the future.

Interstitial cells of Cajal and gastrointestinal inflammation and immunity

Interstitial cells of Cajal (ICC) in gastrointestinal tract are closely linked to gastrointestinal inflammation and dysmotility from various causes. During gastrointestinal inflammation, ICC show varying degrees of changes in their structure, number and functions. In addition, the immune mechanisms involved in the pathogenesis of gastrointestinal inflammation have also attracted wide attention. In this article, we will review the changes in ICC in gastrointestinal inflammation and immunity.

Inflammatory bowel disease in rats: Bacterial and chemical interaction

AIM: To develop a novel model of colitis in rats, using a combination of iodoacetamide and enteropathogenic E. coli (EPEC), and to elucidate the pathophysiologic processes implicated in the development of ulcerative colitis (UC).

METHODS: Male Sprague-Dawley rats (n = 158) were inoculated intrarectally on a weekly basis with 4 different combinations: (a) 1% methylcellulose (MC), (b) 100 &mgr;L of 6% iodoacetamide (IA) in 1% MC, (c) 200 &mgr;L containing 4 × 10⁸ colony factor units (CFU) of EPEC, and (d) combined treatment of (IA) followed by bacteria (B) after 2 d. Thirty days post treatment, each of the four groups was divided into two subgroups; the inoculation was stopped for one subgroup and the other subgroup continued with biweekly inoculation until the end of the experiment. Colitis was evaluated by the clinical course of the disease, the macroscopic and microscopic alterations, activity of myeloperoxidase (MPO), and by TNF-α gene expression.

RESULTS: Findings indicative of UC were seen in the combined treatment (IA + B) as well as the IA continued treatment groups: the animals showed slow rate of increase in body weight, diarrhea, bloody stools, high colonic ulcer score, as well as histological alterations characteristic of UC, with an extensive inflammatory reaction. During the course of the experiment, the MPO activity was consistently elevated and the TNF-α gene expression was upregulated compared to the control animals.

CONCLUSION: The experimental ulcerative colitis model used in the present study resembles, to a great extent, the human disease. It is reproducible with characteristics indicative of chronicity.