Doai Memorial Hospital

Organ morphogenesis is essential for not only integrated organ functions in the body but also the determination of adult-tissue stem cells and their niche. Only hair follicle organs can cyclically regenerate in the variable bulbous germinative region as a form of programmed organ regeneration in adults. Here, we identified a cell population, hair follicle organ-intrinsic mesenchymal cells, with PDGFRα+/Sca1+/CD34high+ mesenchymal cells, from the boundary zone of the epithelial stem cell niche by using the organ germ method, which plays essential roles in entering and promoting the downgrowth phase of the hair cycle. The bioengineered hair follicle germ reconstituted from bulge region-derived epithelial stem cells, dermal papillae and mesenchymal cells has full functions, including downgrowth, full-size hair follicle regeneration and the hair cycle, both in in vitro artificial skin and after intracutaneous skin transplantation. This study provides significant contributions to the basic and medical science of adult organ-inductive potential stem cells and their niches in organ morphogenesis and the adult hair cycle.

The dose of bendamustine used to treat previously untreated follicular lymphoma (FL) is sometimes reduced based on various clinical considerations, but the impact of such dose reductions on outcomes is unclear. We retrospectively analyzed 92 untreated FL patients treated with bendamustine at seven institutions in Japan. Dose reduction was defined as receiving less than 90% of the planned total dose of 1080 mg/m2 over six cycles. Patients with disease progression observed at ≤ 180 days of treatment initiation were defined as primary bendamustine-refractory (PBR). The 3-year overall survival (OS) and progression-free survival (PFS) were 87.1% and 71.8%, respectively. Seven patients were classified as PBR, six of whom received bendamustine at full dose without dose reduction, and they had significantly worse OS with 3-year OS of 38.1%. We excluded the PBR cases from subsequent analyses of the dose intensity's prognostic significance. The dose-reduction group had a significantly lower CR rate (93.0% vs. 74.4%, p = 0.032). Similarly, the 3-year PFS was significantly worse in the dose-reduction group (86.8% vs. 68.1%, p = 0.005). In univariate and multivariate analyses, dose reduction was associated with inferior PFS. In an analysis limited to patients who completed all six courses, the CR rate was comparable between the two groups, but 3-year PFS was significantly worse in the dose-reduction group (86.8% vs. 68.7%, p = 0.041). Furthermore, even among patients who achieved CR, the 3-year PFS tended to be poorer in the dose-reduction group (85.7% vs. 72.7%, p = 0.062). These findings suggest that PBR cases are resistant to bendamustine itself regardless of the dose intensity. In contrast, among responders including those who achieved CR, dose reduction was associated with poorer PFS, indicating that maintaining treatment intensity is important for improving prognosis in the treatment of bendamustine-responsive FL patients.

Abstract Disclosure: Y. Tsujimoto: None. A. Ishida: None. H. Shichi: None. N. Yamamoto: None. Y. Motomura: None. Y. Oi-Yo: None. Y. Sasaki: None. M. Suzuki: None. S. Urai: None. H. Bando: None. M. Yamamoto: None. M. Takahashi: None. G. Iguchi: None. N. Inoshita: None. S. Yamada: None. W. Ogawa: None. H. Fukuoka: None. Background: Several predictive markers for drug selection in acromegaly (Acro) are known, most based on hormonal suppression effects. Acro is characterized by excessive growth hormone secretion and clinical tumor effects due to the high prevalence of macroadenomas, making it essential to predict drug responsiveness for tumor shrinkage. In oncology, patient-derived 3D tumor culture systems have proven to be reliable tools for evaluating drug responses, bridging the gap between in vitro experiments and clinical studies. This study aimed to develop a similar model for Acro to assess drug responsiveness and evaluate its potential for predicting treatment outcomes. Methods: Tumor specimens from 27 Acro patients (median age: 46 [range: 36-56] years; female/male ratio: 13/14) were collected postoperatively and processed into 3D cell culture, as previously described (Tsujimoto Y, et al. J Endocr Soc. 2021; bvab055.). The culture cells were treated with therapeutic agents—octreotide (Oct) 10 nM, cabergoline (Cab) 10 nM, pasireotide (Pas) 10 nM, or vehicle—under standardized conditions. The drug response was defined as a statistically significant reduction in cell viability compared to vehicle-treated controls, as measured by the RealTime-Glo™ MT Cell Viability Assay, which provided real-time feedback on the drugs' cytotoxic effects. Fisher's exact tests and Mann-Whitney U test evaluated associations between responsiveness and clinical or histological factors. Results: Among the 27 cases, 9 (33%) responded to Oct, with an association observed in tumors with T2WI hypointensity on MRI (p = 0.04). The responsiveness to Cab was observed in 9 cases (33%), with an association in patients who responded to the bromocriptine test (p = 0.04). Pas exhibited the highest response rate (11 cases, 40%), which was associated with sparsely granulated tumors (p = 0.04).Discussion:The use of a 3D tumor culture system derived from Acro patients provided insights into drug-specific responsiveness, aligning with previously identified predictive factors for Oct, Cab, and Pas. However, it is important to note that most previously reported predictive factors focus primarily on biochemical remission. The assay's ability to measure real-time cell viability represents a significant advancement in evaluating treatment efficacy, particularly for tumor shrinkage, which has historically been challenging to predict. Integrating this approach into clinical practice, particularly for postoperative residual cases, could enable personalized medicine by refining drug selection based on tumor characteristics. Further validation in larger cohorts and prospective clinical trials is warranted to establish its broader applicability and cost-effectiveness. Presentation: Saturday, July 12, 2025

Disclosure: M. Usutani: None. S. Takayasu: None. S. Yamada: None. Y. Fujita: None.Background: Cushing disease is caused by the dysregulation of ACTH synthesis and secretion due to corticotroph tumors (ACTHomas). Typical ACTHomas exhibit a partial lack of response to glucocorticoid (GC) negative feedback, although the underlying mechanism remains largely unclear. Recently, a second POMC promoter regulated by methylation status was identified in human ACTHomas. However, it is currently unknown whether the methylation levels of the POMC promoters are involved in the GC resistance observed in ACTHomas. Method: To assess methylation/demethylation positions in the first and second promoters, we performed bisulfite-conversion-based DNA sequencing of the CpG islands in 16 ACTHoma cases. The expression levels of ten-eleven translocation (TET) enzymes and DNA methyltransferases (DNMT) were evaluated using qPCR. The same experiments were conducted using the murine corticotroph tumor cell line AtT-20. Subsequently, we investigated changes in the methylation status of the two POMC promoters in human primary cultured cells following treatment with synthetic GC Dexamethasone (DEX), and explored their association with clinical GC resistance. Results: For the first promoter, we found that in the group where methylation decreased after DEX treatment, basal cortisol levels and cortisol levels after low-dose DEX administration were significantly higher compared to the group with increased methylation. No correlation was found between methylation levels and clinical data for the second promoter. The expression levels of TET and DNMT families were significantly increased by DEX in the group where methylation of the first promoter increased after DEX treatment. In contrast, the CpG islands of the first and second promoters were highly demethylated in AtT-20 cells, and DEX treatment had no effect on their methylation levels. The expression levels of Tet and Dnmt were slightly decreased following DEX treatment in AtT-20 cells. Discussion: The decrease in methylation of the first promoter appears to correlate with an increase in basal cortisol levels and cortisol levels after the low-dose DEX test, suggesting that GC-induced demethylation in the first promoter may partially contribute to resistance to the negative regulation of POMC transcription in ACTHomas. Although DEX treatment did not alter methylation levels in the second promoter, it was confirmed that basal cortisol levels were higher in the group with low basal methylation levels in the second promoter. Thus, the methylation status of the second promoter may regulate basal cortisol levels. Furthermore, differences between species and samples should be considered, as these may affect the results. Conclusion: Low methylation of the second POMC promoter was found to increase serum cortisol levels, and the degree of resistance to GCs may be regulated by GC-induced demethylation levels of the first POMC promoter in ACTHomas.Presentation: Monday, July 14, 2025

As coronavirus disease 2019 (COVID-19) outbreaks in healthcare facilities are a serious public health concern, we performed a case-control study to investigate the risk of COVID-19 infection in healthcare workers. We collected data on participants' sociodemographic characteristics, contact behaviors, installation status of personal protective equipment, and polymerase chain reaction testing results. We also collected whole blood and assessed seropositivity using the electrochemiluminescence immunoassay and microneutralization assay. In total, 161 (8.5%) of 1,899 participants were seropositive between August 3 and November 13, 2020. Physical contact (adjusted odds ratio 2.4, 95% confidence interval 1.1-5.6) and aerosol-generating procedures (1.9, 1.1-3.2) were associated with seropositivity. Using goggles (0.2, 0.1-0.5) and N95 masks (0.3, 0.1-0.8) had a preventive effect. Seroprevalence was higher in the outbreak ward (18.6%) than in the COVID-19 dedicated ward (1.4%). Results showed certain specific risk behaviors of COVID-19; proper infection prevention practices reduced these risks.