Efficacy of using red dichromatic imaging throughout endoscopic submucosal dissection procedure.

BACKGROUND: Management of bleeding during endoscopic submucosal dissection (ESD) is critical. Red Dichromatic Imaging (RDI), a novel image-enhanced endoscopy technology, has been reported to improve the visibility of deep vessels and bleeding source compared to white light imaging (WLI). We hypothesized that using RDI during the entire cutting process (full time RDI ESD: FTR-ESD), higher R0 resection rate, shorter procedure time and fewer complications could be achieved. Therefore, the aims of the present study were to investigate the efficacy and safety of FTR-ESD. METHODS: This retrospective observational study included a total of 82 consecutive patients who underwent ESD by a single expert endoscopist for 40 esophageal, 17 gastric and 25 colorectal cancers at our institution from January 2018 to March 2021. The clinicopathological data were collected from patients' medical records and the treatment outcomes were analyzed according to the treatment phase (early; 57 WLI-ESD and late; 25 FTR-ESD). RESULTS: The median of the greatest diameter of resected specimen was 40.0 mm. The median procedure time was relatively shorter in the FTR-ESD group (35 min) than in the WLI-ESD group (40 min), but the difference was not statistically significant (p = 0.34). The median dissection speed in the FTR-ESD group (27.23 mm2/min) was significantly faster than that in the WLI-ESD group (20.94 mm2/min) (p = 0.025). The dissection speed was not different among different organs. A multivariate analysis revealed that tumor size (more than 30 mm) and FTR-ESD were significant independent factors contributing to faster dissection speed (p < 0.05). There were no significant differences in the rates of en bloc resection, HM0, VM0 or occurrence of adverse events between WLI-ESD and FTR-ESD. CONCLUSIONS: FTR-ESD significantly increases the dissection speed compared to WLI-ESD. FTR-ESD can be performed safely and therapeutic outcomes in FTR-ESD are comparable with WLI-ESD. A further multicenter prospective study is warranted to confirm our results.

[Ulcerative colitis complicated by pyoderma gangrenosum and multiple aseptic abscesses].

A woman in her 30s was diagnosed with ulcerative colitis (UC) 4 years ago and treated with tacrolimus, azathioprine, and prednisolone 5mg (PSL). Skin ulcers appeared on the right lower leg during the course of treatment, diagnosed as pyoderma gangrenosum (PG). The patient initially improved with an increased PSL and infliximab dose, but then developed multiple skin ulcers and folliculitis throughout her body. She was transferred to our hospital for PG exacerbation treatment. She developed fever after transfer and contrast-enhanced computed tomography showed multiple abscesses in the lungs and kidneys. PSL was decreased and infliximab was discontinued. Antibiotic therapy and granulocyte/monocyte apheresis (GMA) were started. Fever persisted even after antibiotic treatment, and her general condition did not improve. A right renal abscess puncture was performed. Pus was sterile. A sterile abscess associated with PG was suspected. The PSL dose was increased to 1mg/kg and infliximab restarted. Thereafter, the patient's general condition improved, and both lung and renal abscesses contracted. Skin ulcer epithelialization was also observed. Abdominal symptoms were mild during the course of the disease, and colonoscopy showed only a localized ulcerative lesion in the rectum. The patient was later transferred to the department of dermatology at our hospital for PG treatment. Aseptic abscesses are caused by neutrophil infiltration without infection and have been reported to be associated with neutrophilic dermatosis and inflammatory bowel disease. UC-associated aseptic abscess is rare. This is only the sixth case in Japan. Aseptic abscesses can occur in various sites, including subcutaneous and deep organs, but this is the first kidney abscess case. In previous reports, PSL, infliximab, colchicine, and infliximab+GMA were used for aseptic abscesses associated with UC. They all showed abscess reduction. Aseptic abscesses associated with PG should be considered if abscess lesions occur during the course of UC, and a treatment strategy including enhanced immunosuppression should be considered.

The distribution and function of aquaporins in the kidney: resolved and unresolved questions.

The membrane water channel aquaporin (AQP) family is composed of 13 isoforms in mammals, eight of which are reportedly expressed in the kidney: AQP1, 2, 3, 4, 6, 7, 8, and 11. These isoforms are differentially expressed along the renal tubules and collecting ducts. AQP1 and 7 are distributed in the proximal tubules, whereas AQP2, 3, and 4 occur in the collecting duct system. They play important roles in the reabsorption of water and some solutes across the plasma membrane. In contrast to other aquaporins found in the kidney, AQP6, 8, and 11 are localized to the cytoplasm rather than to the apical or basolateral membranes. It is therefore doubtful that these isoforms are directly involved in water or solute reabsorption. AQP6 is localized in acid-secreting type A intercalated cells of the collecting duct. AQP8 has been found in the proximal tubule but its cellular location has not yet been defined by immunohistochemistry. AQP11 seems to be localized in the endoplasmic reticulum (ER) of proximal tubule cells. Interestingly, polycystic kidneys develop in AQP11-null mice. Many vacuole-like structures are seen in proximal tubule cells in kidneys of newborn AQP11-null mice. Subsequently, cysts are generated, and most of the mice die within a month due to severe renal failure. Although ER stress and impairment of polycystin-1, the product of the gene mutated in autosomal-dominant polycystic kidney disease, are possible causes of cystogenesis in AQP11-null mice, the exact mechanism of pathogenesis and the physiological function of AQP11 are yet to be resolved.