Leukocyte dysfunction and reduced CTLA-4 expression are associated with perianal Crohn's disease.

Although perianal Crohn's disease (PCD) is highly associated with the exacerbated inflammation, the molecular basis and immunological signature that distinguish patients who present a history of perianal lesions are still unclear. This paper aims to define immunological characteristics related to PCD. In this cross-sectional observational study, we enrolled 20 healthy controls and 39 CD patients. Blood samples were obtained for the detection of plasma cytokines and lipopolysaccharides (LPS). Peripheral blood mononuclear cells (PBMCs) were phenotyped by flow cytometry. Leukocytes were stimulated with LPS or anti-CD3/anti-CD28 antibodies. Our results show that CD patients had augmented plasma interleukin (IL)-6 and LPS. However, their PBMC was characterized by decreased IL-6 production, while patients with a history of PCD produced higher IL-6, IL-8, and interferon-γ, along with decreased tumor necrosis factor alpha (TNF). CD patients had augmented FoxP3 and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) regulatory markers, though the PCD subjects presented a significant reduction in CTLA-4 expression. CTLA-4 as well as IL-6 and TNF responses were able to distinguish the PCD patients from those who did not present perianal complications. In conclusion, IL-6, TNF, and CTLA-4 exhibit a distinct expression pattern in CD patients with a history of PCD, regardless of disease activity. These findings clarify some mechanisms involved in the development of the perianal manifestations and may have a great impact on the disease management.

Divergent androgenic modulation of SARS-CoV-2 infection cooperates with dysregulated immune response to dictate worse COVID-19 outcomes in men.

BACKGROUND: Sex-determined differences are rarely addressed in the management of diseases, despite well-known contrasting outcomes between female and male patients. In COVID-19 there is a remarkable disparity, with higher rates of mortality and more severe acute disease in men compared to women, who are mostly affected by long COVID-19. Furthermore, whether androgens play a protective or detrimental role in COVID-19 is still a matter of debate. Hence, the adequate management of the disease, especially regarding men presenting acute disease aggravation, still needs important data to elucidate the interplay between sex hormones and host immune responses that drive the worse evolution in male patients. METHODS: A cohort of 92 controls and 198 non-severe and severe COVID-19 patients, from both sexes, was assessed for clinical outcomes, plasma steroids, gonadotropins, sex hormone binding globulin (SHBG) and immune mediators, before vaccination. These data were correlated with the global gene expression of blood leukocytes. The androgen receptor (AR) signaling pathway was investigated by transcriptomics and tracheal aspirate was obtained from severe patients for SARS-COV-2 quantification in the respiratory tract. The interplay among clinical, endocrine and immunological data deciphered the sex differences in COVID-19. Importantly, statistical analyses, using 95% confidence interval, considered confounding factors such as age and comorbidities, to definitely parse the role of androgens in the disease outcome. RESULTS: There were notable contrasting levels of testosterone and dihydrotestosterone (DHT) throughout the disease course in male but not female patients. Inflammatory mediators presented significant negative correlations with testosterone, which was partially dependent on age and diabetes in men. Male subjects with severe COVID-19 had a significant up regulation of the AR signaling pathway, including modulation of TMPRSS2 and SRD5A1 genes, which are related to the viral infection and DHT production. Indeed, men had a higher viral load in the tracheal aspirate and levels of DHT were associated with increased relative risk of death. In contrast, the testosterone hormone, which was notably reduced in severe disease, was significantly related with susceptibility to COVID-19 worsening in male patients. Secondary hypogonadism was ruled out in the male severe COVID-19 subjects, as FSH, LH, and SHBG levels were not significantly altered. Instead, these subjects tended to have increased gonadotropin levels. Most interestingly, in this study we identified, for the first time, combined sets of clinical and immunoendocrine parameters that together predicted progression from non-severe to severe COVID-19 in men. One of the limitations of our study was the low or undetectable levels of DHT in many patients. Then, the evaluation of enzymes related to biosynthesis and signaling by androgens was mandatory and reiterated our findings. CONCLUSIONS: These original results unraveled the disease immunoendocrine regulation, despite vaccination or comorbidities and pointed to the fundamental divergent role of the androgens testosterone and DHT in the determination of COVID-19 outcomes in men. Therefore, sex-specific management of the dysregulated responses, treatments or public health measures should be considered for the control of COVID-19 pandemic.

Cinnamaldehyde modulates host immunoinflammatory responses in rat ligature-induced periodontitis and peripheral blood mononuclear cell models.

Cinnamaldehyde is a natural product with anti-inflammatory and immune-modulatory properties, known to regulate host responses to bacterial stimuli. This study aimed to investigate the effects of cinnamaldehyde on ligature-induced periodontitis in rats, and its impact on the modulation of human peripheral blood mononuclear cells (PBMC). Male Wistar rats were assigned into three groups:i) control: no ligature + vehicle; ii) ligature: ligature + vehicle; and iii) ligature + cinnamaldehyde (50 mg/kg); all treatments by daily oral gavage. After 14 days of induced periodontitis, the hemimandibles were collected for bone loss evaluation. The gingival levels of IL-1ß, MMP-9 and iNOS mRNA were evaluated. Nitric oxide (NO) was measured in both rat saliva and plasma. PBMC were stimulated with Aggregatibacter actinomycetemcomitans (Aa) in the presence or absence of cinnamaldehyde (5, 20 e 40 µM), and cytokine production was quantified in cell supernatant. Proliferating lymphocytes were taken for flow cytometer reading, while culture supernatants were used for IFN-γ and IL-10 assessment. The ligature group had both increased alveolar bone loss and gingival expression of IL-1ß, MMP-9 and iNOS compared to the control group. All parameters were attenuated by cinnamaldehyde treatment. Lower salivary but not plasma NO was detected in the cinnamaldehyde compared to the ligature group. Aa-stimulated PBMCs treated with cinnamaldehyde produced less IL-1ß; the compound also attenuated lymphocyte proliferation in a dose-dependent manner, as well as cell IL-10 production. Cinnamaldehyde treatment reduced periodontal bone loss, and downregulated key inflammatory mediators and human PBMC responses, pointing to novel potential therapeutic effects of this compound.

Peroxisome Proliferator-Activated Receptor Alpha Mediates the Beneficial Effects of Atorvastatin in Experimental Colitis.

The current therapeutic options for Inflammatory Bowel Diseases (IBD) are limited. Even using common anti-inflammatory, immunosuppressive or biological therapies, many patients become unresponsive to the treatments, immunosuppressed or unable to restrain secondary infections. Statins are cholesterol-lowering drugs with non-canonical anti-inflammatory properties, whose underlying mechanisms of action still remain poorly understood. Here, we described that in vitro atorvastatin (ATO) treatment was not toxic to splenocytes, constrained cell proliferation and modulated IL-6 and IL-10 production in a dose-dependent manner. Mice exposed to dextran sulfate sodium (DSS) for colitis induction and treated with ATO shifted their immune response from Th17 towards Th2, improved the clinical and histological aspects of intestinal inflammation and reduced the number of circulating leukocytes. Both experimental and in silico analyses revealed that PPAR-α expression is reduced in experimental colitis, which was reversed by ATO treatment. While IBD patients also downregulate PPAR-α expression, the responsiveness to biological therapy relied on the restoration of PPAR-α levels. Indeed, the in vitro and in vivo effects induced by ATO treatment were abrogated in Ppara-/- mice or leukocytes. In conclusion, the beneficial effects of ATO in colitis are dependent on PPAR-α, which could also be a potential predictive biomarker of therapy responsiveness in IBD.

The Aryl Hydrocarbon Receptor (AHR) as a Potential Target for the Control of Intestinal Inflammation: Insights from an Immune and Bacteria Sensor Receptor.

The aryl hydrocarbon receptor (AHR) is widely expressed in immune and non-immune cells of the gut and its activation has been correlated to the outcome of inflammatory bowel diseases (IBD). In ulcerative colitis and Crohn's disease, there is an excessive chronic inflammation with massive accumulation of leukocytes in the gut, in an attempt to constrain the invasion of pathogenic microorganisms on the damaged organ. Accordingly, it is known that dietary components, xenobiotics, and some chemicals or metabolites can activate AHR and induce the modulation of inflammatory responses. In fact, the AHR triggering by specific ligands during inflammatory conditions results in decreased IFNγ, IL-6, IL-12, TNF, IL-7, and IL-17, along with reduced microbial translocation and fibrosis in the gut. Moreover, upon AHR activation, there are increased regulatory mechanisms such as IL-10, IL-22, prostaglandin E2, and Foxp3, besides the production of anti-microbial peptides and epithelial repair. Most interestingly, commensal bacteria or their metabolites may also activate this receptor, thus contributing to the restoration of gut normobiosis and homeostasis. In line with that, Lactobacillus reuteri, Lactobacillus bulgaricus, or microbial products such as tryptophan metabolites, indole-3-pyruvic acid, urolithin A, short-chain fatty acids, dihydroxyquinoline, and others may regulate the inflammation by mechanisms dependent on AHR activation. Hence, here we discussed the potential modulatory role of AHR on intestinal inflammation, focused on the reestablishment of homeostasis through the receptor triggering by microbial metabolites. Finally, the development of AHR-based therapies derived from bacteria products could represent an important future alternative for controlling IBD.

Reappraisal of antibodies against Saccharomyces cerevisiae (ASCA) as persistent biomarkers in quiescent Crohn's disease.

A clear correlation exists between microbiota and the dysregulation of the immune response in Inflammatory Bowel Diseases (IBD), which comprise Crohn's disease (CD) and ulcerative colitis (UC). These unbalanced reactions also involve humoral responses, with antibodies against Saccharomyces cerevisiae. Thus, here we aimed to quantify IgA and IgG specific to S. cerevisiae (ASCA) in quiescent CD and UC, to correlate the production of these antibodies with patient's inflammatory response and disease clinical presentation. Twenty-nine subjects (16 CD and 13 UC) and 45 healthy controls were enrolled in this study and had plasma samples tested for ASCA and cytokines (IL-2, IL-4, IL-6, IL-10, IFN-γ, TNF-α), besides clinical evaluation. IBD patients had increase IgA and IgG ASCA, especially those with colonic (L2) and fistulizing (B3) CD. Similarly, patients who dropped out the treatment had augmented ASCA, while IgG was reduced in those receiving sulfasalazine treatment. Furthermore, the quiescent CD patients had elevated IL-6 on plasma, especially in the absence of treatment, together with increased counter regulatory response of IL-10. There was a positive correlation between IgA and IgG on CD but not UC, as well as between IgA and TNF in total IBD patients. In addition, the levels of IgG x TNF, IgA x IL-10 and IgG x IL-10 were also correlated in CD, indicating that ASCA production may be influenced by the inflammatory response. Finally, we concluded that ASCA could be pointed as relevant biomarker of CD presentation and residual inflammation, even in clinical remission patients.