TiO2 nanoparticles abrogate the protective effect of the Crohn's disease-associated variation within the PTPN22 gene locus

OBJECTIVE

Inflammatory bowel disease (IBD) is a multifactorial condition driven by genetic and environmental risk factors. A genetic variation in the protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene has been associated with autoimmune disorders while protecting from the IBD subtype Crohn's disease. Mice expressing the murine orthologous PTPN22-R619W variant are protected from intestinal inflammation in the model of acute dextran sodium sulfate (DSS)-induced colitis. We previously identified food-grade titanium dioxide (TiO₂, E171) as a neglected IBD risk factor. Here, we investigate the interplay of the PTPN22 variant and TiO₂-mediated effects during IBD pathogenesis.

DESIGN

Acute DSS colitis was induced in wild-type and PTPN22 variant mice (PTPN22-R619W) and animals were treated with TiO₂ nanoparticles during colitis induction. Disease-triggering mechanisms were investigated using bulk and single-cell RNA sequencing.

RESULTS

In mice, administration of TiO₂ nanoparticles abrogated the protective effect of the variant, rendering PTPN22-R619W mice susceptible to DSS colitis. In early disease, cytotoxic CD8⁺ T-cells were found to be reduced in the lamina propria of PTPN22-R619W mice, an effect reversed by TiO₂ administration. Normalisation of T-cell populations correlated with increased Ifng expression and, at a later stage of disease, the promoted prevalence of proinflammatory macrophages that triggered severe intestinal inflammation.

CONCLUSION

Our findings indicate that the consumption of TiO₂ nanoparticles might have adverse effects on the gastrointestinal health of individuals carrying the PTPN22 variant. This demonstrates that environmental factors interact with genetic risk variants and can reverse a protective mechanism into a disease-promoting effect.

Ingested nano- and microsized polystyrene particles surpass the intestinal barrier and accumulate in the body

Plastic pollution is a major global challenge of our times, baring a potential threat for the environment and the human health. The increasing abundance of nanoplastic (NP) and microplastic (MP) particles in the human diet might negatively affect human health since they - particularly in patients suffering from inflammatory bowel disease (IBD) - might surpass the intestinal barrier. To investigate whether ingested plastic particles cross the intestinal epithelium and promote bowel inflammation, mice were supplemented with NP or MP polystyrene (PS) particles for 24 or 12 weeks before inducing acute or chronic dextran sodium sulfate (DSS) colitis with continuous plastic administration. Although ingested PS particles accumulated in the small intestine and organs distant from the gastrointestinal tract, PS ingestion did not affect intestinal health nor did it promote colitis severity. Although the lack of colitis-promoting effects of small PS particles might be a relief for IBD patients, potential accumulative effects of ingested plastic particles on the gastrointestinal health cannot be excluded.

Combination of Vedolizumab With Tacrolimus Is More Efficient Than Vedolizumab Alone in the Treatment of Experimental Colitis

BACKGROUND

Vedolizumab is a widely used and safe therapy in inflammatory bowel disease, particularly in ulcerative colitis (UC), making it a promising candidate for enhanced efficacy by combining it with additional immunomodulatory medications. In this study, we studied the impact of vedolizumab monotreatment vs vedolizumab coadministration with other immunomodulatory drugs on intestinal inflammation and intestinal immune cells in vivo.

METHODS

Colon tissue from human patients with UC with active disease or in remission with or without vedolizumab treatment was stained by immunohistochemistry. We reconstituted NOD-SCID-SGM3 mice with human CD34+ cells and treated them with dextran sodium sulfate to induce acute colitis. Mice were treated with vedolizumab alone, or in combination with tacrolimus, ozanimid, or tofacitinib.

RESULTS

Vedolizumab reduced the number of CD3+ T cells and CD68+ monocytes/macrophages in the colon of patients with UC with active disease. Vedolizumab moderately decreased immune cell numbers in acute dextran sodium sulfate-induced colitis. The combination of vedolizumab with tacrolimus further reduced the number of infiltrating CD3+ T cells and CD68+ monocytes/macrophages and was superior in ameliorating intestinal inflammation when compared to vedolizumab monotreatment. In contrast, cotreatment using vedolizumab with ozanimod or tofacitinib had no additive effect.

CONCLUSIONS

Our data show that vedolizumab reduces the number of innate and adaptive immune cells in the mucosa of patients with UC. Further, the combination of vedolizumab with tacrolimus was more efficient to reduce immune cell numbers and to increase therapeutic efficacy than vedolizumab monotreatment. This finding indicates that combination treatment using these two drugs may be beneficial for patients who do not respond to vedolizumab monotherapy.

Protein tyrosine phosphatase nonreceptor type 2 controls colorectal cancer development

Protein tyrosine phosphatase nonreceptor type 2 (PTPN2) recently emerged as a promising cancer immunotherapy target. We set out to investigate the functional role of PTPN2 in the pathogenesis of human colorectal carcinoma (CRC), as its role in immune-silent solid tumors is poorly understood. We demonstrate that in human CRC, increased PTPN2 expression and activity correlated with disease progression and decreased immune responses in tumor tissues. In particular, stage II and III tumors displayed enhanced PTPN2 protein expression in tumor-infiltrating T cells, and increased PTPN2 levels negatively correlated with expression of PD-1, CTLA4, STAT1, and granzyme A. In vivo, T cell- and DC-specific PTPN2 deletion reduced tumor burden in several CRC models by promoting CD44+ effector/memory T cells, as well as CD8+ T cell infiltration and cytotoxicity in the tumor. In direct relevance to CRC treatment, T cell-specific PTPN2 deletion potentiated anti-PD-1 efficacy and induced antitumor memory formation upon tumor rechallenge in vivo. Our data suggest a role for PTPN2 in suppressing antitumor immunity and promoting tumor development in patients with CRC. Our in vivo results identify PTPN2 as a key player in controlling the immunogenicity of CRC, with the strong potential to be exploited for cancer immunotherapy.

Energy Drink Administration Ameliorates Intestinal Epithelial Barrier Defects and Reduces Acute DSS Colitis

BACKGROUND

The rise in the prevalence of inflammatory bowel diseases in the past decades coincides with changes in nutritional habits, such as adaptation of a Western diet. However, it is largely unknown how certain nutritional habits, such as energy drink consumption, affect intestinal inflammation. Here, we assessed the effect of energy drink supplementation on the development of intestinal inflammation in vitro and in vivo.

METHODS

HT-29 and T84 intestinal epithelial cells and THP-1 monocytic cells were treated with IFNγ in presence or absence of different concentrations of an energy drink. Colitis was induced in C57BL/6 mice by addition of dextran sodium sulfate (DSS) to drinking water with or without supplementation of the energy drink.

RESULTS

Energy drink supplementation caused a dose-dependent decrease in IFNγ-induced epithelial barrier permeability, which was accompanied by upregulation of the pore-forming protein claudin-2. Administration of the energy drink reduced secretion of the pro-inflammatory cytokines interleukin-6 and tumor necrosis factor-α from HT-29, T84, and THP-1 cells. In vivo, energy drink administration reduced clinical symptoms of DSS-induced colitis and epithelial barrier permeability. Endoscopic and histologic colitis scores and expression of pro-inflammatory cytokines were significantly reduced by energy drink co-administration.

CONCLUSION

Energy drink consumption seems to exert an unexpected anti-inflammatory effect in vitro and in vivo in our experimental setting. However, our experimental approach focuses on intestinal inflammation and neglects additional effects of energy drink consumption on the body (eg, on metabolism or sleep). Therefore, the translation of our findings into the human situation must be taken with caution.

Titanium Dioxide Presents a Different Profile in Dextran Sodium Sulphate-Induced Experimental Colitis in Mice Lacking the IBD Risk Gene Ptpn2 in Myeloid Cells

Environmental and genetic factors have been demonstrated to contribute to the development of inflammatory bowel disease (IBD). Recent studies suggested that the food additive; titanium dioxide (TiO2) might play a causative role in the disease. Therefore, in the present study we aimed to explore the interaction between the food additive TiO2 and the well-characterized IBD risk gene protein tyrosine phosphatase non-receptor type 2 (Ptpn2) and their role in the development of intestinal inflammation. Dextran sodium sulphate (DSS)-induced acute colitis was performed in mice lacking the expression of Ptpn2 in myeloid cells (Ptpn2LysMCre) or their wild type littermates (Ptpn2fl/fl) and exposed to the microparticle TiO2. The impact of Ptpn2 on TiO2 signalling pathways and TiO2-induced IL-1β and IL-10 levels were studied using bone marrow-derived macrophages (BMDMs). Ptpn2LysMCre exposed to TiO2 exhibited more severe intestinal inflammation than their wild type counterparts. This effect was likely due to the impact of TiO2 on the differentiation of intestinal macrophages, suppressing the number of anti-inflammatory macrophages in Ptpn2 deficient mice. Moreover, we also found that TiO2 was able to induce the secretion of IL-1β via mitogen-activated proteins kinases (MAPKs) and to repress the expression of IL-10 in bone marrow-derived macrophages via MAPK-independent pathways. This is the first evidence of the cooperation between the genetic risk factor Ptpn2 and the environmental factor TiO2 in the regulation of intestinal inflammation. The results presented here suggest that the ingestion of certain industrial compounds should be taken into account, especially in individuals with increased genetic risk.

Solute carrier family 12 member 2 as a proteomic and histological biomarker of dysplasia and neoplasia in ulcerative colitis

BACKGROUND AND AIMS

Ulcerative colitis (UC) patients have a greater risk of developing colorectal cancer through inflammation-dysplasia-carcinoma sequence of transformation. The histopathological diagnosis of dysplasia is therefore of critical clinical relevance, but dysplasia may be difficult to distinguish from inflammatory changes.

METHODS

A proteomic pilot study on 5 UC colorectal dysplastic patients highlighted proteins differentially distributed between paired dysplastic, inflammatory and normal tissues. The best candidate marker was selected and immunohistochemistry confirmation was performed on AOM/DSS mouse model lesions, 37 UC dysplasia, 14 UC cancers, 23 longstanding UC, 35 sporadic conventional adenomas, 57 sporadic serrated lesions and 82 sporadic colorectal cancers.

RESULTS

Differential proteomics found 11 proteins significantly more abundant in dysplasia compared to inflammation, including Solute carrier family 12 member 2 (SLC12A2) which was confidently identified with 8 specific peptides and was below the limit of quantitation in both inflammatory and normal colon. SLC12A2 immunohistochemical analysis confirmed the discrimination of preneoplastic and neoplastic lesions from inflammatory lesions in mice, UC and in sporadic contexts. A specific SLC12A2 staining pattern termed "loss of gradient" reached 89% sensitivity, 95% specificity and 92% accuracy for UC-dysplasia diagnosis together with an inter-observer agreement of 95.24% (multirater κfree of 0.90; IC95%: 0.78 - 1.00). Such discrimination could not be obtained by Ki67 staining. This specific pattern was also associated with sporadic colorectal adenomas and cancers.

CONCLUSIONS

We found a specific SLC12A2 immunohistochemical staining pattern in precancerous and cancerous colonic UC-lesions which could be helpful for diagnosing dysplasia and cancer in UC and non-UC patients.

Deletion of Protein Tyrosine Phosphatase Nonreceptor Type 2 in Intestinal Epithelial Cells Results in Upregulation of the Related Phosphatase Protein Tyrosine Phosphatase Nonreceptor Type 23

Background/Aims

Knockdown of protein tyrosine phosphatase nonreceptor type 2 (PTPN2) exaggerates IFN-γ-induced intestinal barrier defects, but mice constitutively lacking PTPN2 in epithelial cells (PTPN2xVilCre mice) do not show changes in epithelial function or enhanced susceptibility to experimental colitis. Here, we investigated whether PTPN2 modulates the expression of related tyrosine phosphatases.

Methods

PTPN2 knockdown in HT-29 cells was induced using siRNA constructs. Acute colitis in PTPN2xVilCre mice was induced by 2% dextran sulfate sodium (DSS) in drinking water for 7 days. Colitis-associated tumors were induced by injection of azoxymethane prior to treatment with DSS for 3 consecutive cycles.

Results

In HT-29 cells, PTPN2 depletion resulted in enhanced mRNA expression of PTPN11 and PTPN23 and in parallel to upregulation of IL-18 mRNA upon treatment with TNF for 24 h. DSS treatment of PTPN2-deficient mice resulted in a strong induction of Ptpn23 mRNA in colon tissue in vivo. In the tumor model, Ptpn23 mRNA was again clearly upregulated in nontumor tissue from PTPN2-deficient mice; however, this was not observed in tumor tissue.

Conclusions

Our experiments show that PTPN23 function might, at least partially, compensate lack of PTPN2 in epithelial cells. Upregulation of PTPN23 might therefore crucially contribute to the lack of a colitis phenotype in PTPN2-VilCre mice.

[The surgical treatment of strangulated inguinal-crural hernias in geriatric patients]

The authors describe their own experience relative to 79 patients, aged 70 years or older, who underwent, during three years, emergency surgical intervention for inguinal or crural strangulated hernia. They report a postoperative mortality rate of 8.8% and a postoperative morbidity rate of 40%. They stress the need for timely diagnosis and a meticulous surgical treatment. Therefore, they underline the great importance of the anesthesiologic approach and perioperative intensive care.

[Autotransfusion: its use in a case of spontaneous splenic rupture in non-Hodgkin's lymphoma]

The article refers to autotransfusion experience in a patient affected by lymphoma (not Hodgkin type), who reached surgery for haemoperitoneum caused by the spontaneous rupture of the spleen. Considering the pathology, this method brought unpredictable variations in the hemochrome thus leading to a deep reflection on the limitations of the use of autotransfusion.

[Anti H2 receptors and perforated peptic ulcer. Review of 442 cases]

H2 blockers have accelerated the reduction in elective peptic ulcer surgery but appear to have had no equivalent effect on the incidence of perforated ulcer success. A 13 year (1975-1987) review of perforated peptic ulcer is presented. The mean annual number of operations for perforation fell from 8.21% to 4.93% after 1980, while the number of operations for perforated gastric ulcer in this period was almost unchanged. A significant reduction was found in mean annual rates for perforated duodenal ulcer from 6.86% to 3.82% after 1980, while the number of operations for perforated gastric ulcer in this period was almost unchanged.