Background Little is known about possible underlying psychological abnormalities and physiology of reflux hypersensitivity (RH) as defined in the recent Rome IV classification. We aimed to assess markers of psychological comorbidity as well as gastro‐esophageal reflux measurements in RH patients compared to controls and also in patients with functional heartburn (FH) and non‐erosive reflux disease (NERD) versus controls. Methods Data of 304 patients visiting our Functional Diagnostics Centre from 2016 to 2018 were analyzed. We focused on a psychological assessment using validated questionnaires (visceral sensitivity index; VSI, hospital anxiety and depression score; HADS) as well as multichannel intraluminal impedance (MII) and pH‐metry data from the diagnostic work‐up. Key Results We found a decreased VSI of 57.8 ± 15.4 points (pts) among RH patients (n = 45) indicating higher visceral sensitivity compared to 85.7 ± 2.0 pts in the control group (n = 31, P < 0.001). Furthermore, a significant difference in VSI was found between the FH (60.8 ± 23.3 pts, n = 59, P < 0.001) and between the NERD (61.9 ± 20.8 pts, n = 67, P < 0.001) both compared to the control group. The HADS also displayed a significant difference between the RH (11.9 ± 6.0 pts, P < 0.001), FH (11.0 ± 7.4 pts, P < 0.001), respectively, NERD (11.3 ± 8.9 pts, P < 0.001) as compared to the control group (2.0 ± 1.4 pts). Conclusions and Inferences Increased sensation to visceral stimuli as well as anxiety and depression appears to play an important role not only in reflux hypersensitivity and functional heartburn as defined by Rome IV but also in NERD. These findings are in line with the disease concept of disorders of gut‐brain interaction in which psychological comorbidities and visceral hypersensitivity play a major role.

Background The single nucleotide polymorphism (SNP) rs1893217 within the gene locus encoding PTPN2 represents a risk factor for inflammatory bowel disease (IBD). Our previous work demonstrated reduced PTPN2 activity and subsequently increased inflammatory signaling upon presence of SNP rs1893217. The naturally occurring polyamine spermidine reduces pro-inflammatory signaling via induction of PTPN2 activity; however, the effect of SNP rs1893217 on the anti-inflammatory potential of spermidine is still unknown. Here, we investigated how presence of SNP rs1893217 affects treatment efficacy of spermidine and whether it might serve as a potential biomarker for spermidine treatment. Methods Human T84 (wild-type [WT] for PTPN2 SNP rs1893217) and HT29 (heterozygous for PTPN2 SNP rs1893217) intestinal epithelial cells (IECs) were treated with several polyamines from the putrescine-spermidine pathway. T84 and HT29 IECs, THP-1 monocytes (WT and transfected with a lentiviral vector expressing PTPN2 SNP rs1893217) and genotyped, patient-derived peripheral blood mononuclear cells were challenged with IFN-γ and/or spermidine. Results Among the analyzed polyamines, spermidine was the most efficient activator of PTPN2 phosphatase activity, regardless of the PTPN2 genotype. Spermidine suppressed IFN-γ-induced STAT1 and STAT3 phosphorylation, along with decreased mRNA expression of ICAM-1, NOD2, and IFNG in IECs and monocytes. Of note, these effects were clearly more pronounced when the disease-associated PTPN2 C-variant in SNP rs1893217 was present. Conclusions Our data demonstrate that spermidine is the most potent polyamine in the putrescine-spermine axis for inducing PTPN2 enzymatic activity. The anti-inflammatory effect of spermidine is potentiated in the presence of SNP rs1893217, and this SNP might thus be a useful biomarker for possible spermidine-treatment in IBD patients.

Colorectal cancers (CRCs) remain one of the most common and challenging neoplasia in the Western world. The response rate of immunotherapeutic treatment approaches in a subset of advanced CRCs is remarkable and has sustainably changed treatment regimens. Unfortunately, currently available immunotherapeutics only displayed significant antitumoral activity – in terms of progression free survival (PFS) and objective response rate (ORR) – in microsatellite instability-high (MSI-H)/DNA mismatch repair deficient (dMMR) CRCs. Subsequently, these remarkable results had led to the US Food and Drug Administration’s approval of both immune checkpoint inhibitors (ICIs) pembrolizumab and nivolumab in the treatment of advanced MSI-H/dMMR CRCs. However, in microsatellite stable (MSS)/DNA mismatch repair proficient (pMMR) CRCs, ICIs have clearly failed to meet their expectations and are therefore not considered effective. As the vast majority of CRCs display a molecular MSS/pMMR profile, current treatment approaches endeavor to improve tumor immunogenicity that consecutively leads to increased proinflammatory cytokine levels as well as tumor infiltrating T-cells, which in turn may be targeted by various immunotherapeutic agents. Therefore, ongoing studies are investigating novel synergistic therapy modalities and approaches to overcome a “cold” to “hot” tumor conversion in MSS/pMMR CRCs. In this review, we summarize the efficacy and possible immune-related adverse events as well as novel therapeutic approaches of ICIs in the treatment of MSI-H/dMMR and MSS/pMMR CRCs.

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