Low-grade intestinal inflammation two decades after pelvic radiotherapy

Sravani Devarakonda; Annika Thorsell; Per Hedenström; Azar Rezapour; Lisen Heden; Sanghita Banerjee; Malin E V Johansson; George Birchenough; Amelie Toft Morén; Karin Gustavsson; Viktor Skokic; Victor L Pettersson; Fei Sjöberg; Marie Kalm; Mohammad Al Masri; Michaela Ekh; Henrik Fagman; Mats Wolving; Rosie Perkins; Rodrigo A Morales; Francisca Castillo; Eduardo J Villablanca; Ulf Yrlid; Karin Bergmark; Gunnar Steineck; Cecilia Bull

doi:10.1016/j.ebiom.2023.104691

Low-grade intestinal inflammation two decades after pelvic radiotherapy

EBioMedicine. 2023 Aug:94:104691. doi: 10.1016/j.ebiom.2023.104691. Epub 2023 Jul 20.

Authors

Sravani Devarakonda¹, Annika Thorsell², Per Hedenström³, Azar Rezapour⁴, Lisen Heden⁵, Sanghita Banerjee⁶, Malin E V Johansson⁷, George Birchenough⁷, Amelie Toft Morén¹, Karin Gustavsson⁵, Viktor Skokic⁸, Victor L Pettersson¹, Fei Sjöberg⁹, Marie Kalm¹⁰, Mohammad Al Masri¹, Michaela Ekh¹, Henrik Fagman¹¹, Mats Wolving¹², Rosie Perkins¹³, Rodrigo A Morales⁶, Francisca Castillo⁶, Eduardo J Villablanca⁶, Ulf Yrlid⁴, Karin Bergmark¹, Gunnar Steineck¹, Cecilia Bull¹⁴

Affiliations

¹ Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
² Proteomics Core Facility, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
³ Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden; Department of Gastroenterology and Hepatology, Sahlgrenska University Hospital, Gothenburg, Sweden.
⁴ Department of Microbiology and Immunology, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
⁵ Pelvic Cancer Rehabilitation, Sahlgrenska University Hospital, Gothenburg, Sweden.
⁶ Immunology and Allergy Unit, Department of Medicine, Solna, Karolinska Institute and University Hospital, Stockholm, Sweden.
⁷ Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
⁸ Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Molecular Medicine and Surgery and Department of Pelvic Cancer, Karolinska Institute, Stockholm, Sweden.
⁹ Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Department of Infectious Diseases, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg, 413 90 Gothenburg, Sweden.
¹⁰ Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, 413 90 Gothenburg, Sweden.
¹¹ Department of Laboratory Medicine, Institute of Biomedicine, The Sahlgrenska Academy, University of Gothenburg and Department of Clinical Patology, Sahlgrenska University Hospital, Gothenburg, Sweden.
¹² Department of Pathology, Sahlgrenska University Hospital, Göteborg, Sweden.
¹³ Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
¹⁴ Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. Electronic address: Cecilia.bull@gu.se.

Abstract

Background: Radiotherapy is effective in the treatment of cancer but also causes damage to non-cancerous tissue. Pelvic radiotherapy may produce chronic and debilitating bowel symptoms, yet the underlying pathophysiology is still undefined. Most notably, although pelvic radiotherapy causes an acute intestinal inflammation there is no consensus on whether the late-phase pathophysiology contains an inflammatory component or not. To address this knowledge gap, we examined the potential presence of a chronic inflammation in mucosal biopsies from irradiated pelvic cancer survivors.

Methods: We biopsied 24 cancer survivors two to 20 years after pelvic radiotherapy, and four non-irradiated controls. Using tandem mass tag (TMT) mass spectrometry and mRNA sequencing (mRNA-seq), we charted proteomic and transcriptomic profiles of the mucosal tissue previously exposed to a high or a low/no dose of radiation. Changes in the immune cell populations were determined with flow cytometry. The integrity of the protective mucus layers were determined by permeability analysis and 16S rRNA bacterial detection.

Findings: 942 proteins were differentially expressed in mucosa previously exposed to a high radiation dose compared to a low radiation dose. The data suggested a chronic low-grade inflammation with neutrophil activity, which was confirmed by mRNA-seq and flow cytometry and further supported by findings of a weakened mucus barrier with bacterial infiltration.

Interpretation: Our results challenge the idea that pelvic radiotherapy causes an acute intestinal inflammation that either heals or turns fibrotic without progression to chronic inflammation. This provides a rationale for exploring novel strategies to mitigate chronic bowel symptoms in pelvic cancer survivors.

Funding: This study was supported by the King Gustav V Jubilee Clinic Cancer Foundation (CB), The Adlerbertska Research Foundation (CB), The Swedish Cancer Society (GS), The Swedish State under the ALF agreement (GS and CB), Mary von Sydow's foundation (MA and VP).

Keywords: Neutrophil; Pelvic radiation disease; Pelvic radiotherapy; Proctitis; Proteomics; Transcriptomics.