Regulation of metaplasia and dysplasia in the stomach by the stromal microenvironment.

Research on the microenvironment associated with gastric carcinogenesis has focused on cancers of the stomach and often underestimates premalignant stages such as metaplasia and dysplasia. Since epithelial interactions with T cells, macrophages, and type 2 innate lymphoid cells (ILC2s) are indispensable for the formation of precancerous lesions in the stomach, understanding the cellular interactions that promote gastric precancer warrants further investigation. Although various types of immune cells have been shown to play important roles in gastric carcinogenesis, it remains unclear how stromal cells such as fibroblasts influence epithelial transformation in the stomach, especially during precancerous stages. Fibroblasts exist as distinct populations across tissues and perform different functions depending on the expression patterns of cell surface markers and secreted factors. In this review, we provide an overview of known microenvironmental components in the stroma with an emphasis on fibroblast subpopulations and their roles during carcinogenesis in tissues including breast, pancreas, and stomach. Additionally, we offer insights into potential targets of tumor-promoting fibroblasts and identify open areas of research related to fibroblast plasticity and the modulation of gastric carcinogenesis.

Interleukin 13 Promotes Maturation and Proliferation in Metaplastic Gastroids.

BACKGROUND & AIMS: Type 2 innate lymphoid cells (ILC2s) and interleukin-13 (IL-13) promote the onset of spasmolytic polypeptide-expressing metaplasia (SPEM) cells. However, little is known about molecular effects of IL-13 in SPEM cells. We now sought to establish a reliable organoid model, Meta1 gastroids, to model SPEM cells in vitro. We evaluated cellular and molecular effects of ILC2s and IL-13 on maturation and proliferation of SPEM cells. METHODS: We performed single-cell RNA sequencing to characterize Meta1 gastroids, which were derived from stomachs of Mist1-Kras transgenic mice that displayed pyloric metaplasia. Cell sorting was used to isolate activated ILC2s from stomachs of IL-13-tdTomato reporter mice treated with L635. Three-dimensional co-culture was used to determine the effects of ILC2s on Meta1 gastroids. Mouse normal or metaplastic (Meta1) and human metaplastic gastroids were cultured with IL-13 to evaluate cell responses. Air-Liquid Interface culture was performed to test long-term culture effects of IL-13. In silico analysis determined possible STAT6-binding sites in gene promoter regions. STAT6 inhibition was performed to corroborate STAT6 role in SPEM cells maturation. RESULTS: Meta1 gastroids showed the characteristics of SPEM cell lineages in vitro even after several passages. We demonstrated that co-culture with ILC2s or IL-13 treatment can induce phosphorylation of STAT6 in Meta1 and normal gastroids and promote the maturation and proliferation of SPEM cell lineages. IL-13 up-regulated expression of mucin-related proteins in human metaplastic gastroids. Inhibition of STAT6 blocked SPEM-related gene expression in Meta1 gastroids and maturation of SPEM in both normal and Meta1 gastroids. CONCLUSIONS: IL-13 promotes the maturation and proliferation of SPEM cells consistent with gastric mucosal regeneration.

Amphiregulin Switches Progenitor Cell Fate for Lineage Commitment During Gastric Mucosal Regeneration.

BACKGROUND & AIMS: Isthmic progenitors, tissue-specific stem cells in the stomach corpus, maintain mucosal homeostasis by balancing between proliferation and differentiation to gastric epithelial lineages. The progenitor cells rapidly adopt an active state in response to mucosal injury. However, it remains unclear how the isthmic progenitor cell niche is controlled during the regeneration of damaged epithelium. METHODS: We recapitulated tissue recovery process after acute mucosal injury in the mouse stomach. Bromodeoxyuridine incorporation was used to trace newly generated cells during the injury and recovery phases. To define the epithelial lineage commitment process during recovery, we performed single-cell RNA-sequencing on epithelial cells from the mouse stomachs. We validated the effects of amphiregulin (AREG) on mucosal recovery, using recombinant AREG treatment or AREG-deficient mice. RESULTS: We determined that an epidermal growth factor receptor ligand, AREG, can control progenitor cell lineage commitment. Based on the identification of lineage-committed subpopulations in the corpus epithelium through single-cell RNA-sequencing and bromodeoxyuridine incorporation, we showed that isthmic progenitors mainly transition into short-lived surface cell lineages but are less frequently committed to long-lived parietal cell lineages in homeostasis. However, mucosal regeneration after damage directs the lineage commitment of isthmic progenitors towards parietal cell lineages. During recovery, AREG treatment promoted repopulation with parietal cells, while suppressing surface cell commitment of progenitors. In contrast, transforming growth factor-α did not alter parietal cell regeneration, but did induce expansion of surface cell populations. AREG deficiency impairs parietal cell regeneration but increases surface cell commitment. CONCLUSIONS: These data demonstrate that different epidermal growth factor receptor ligands can distinctly regulate isthmic progenitor-driven mucosal regeneration and lineage commitment.

Oncogenic Fatty Acid Metabolism Rewires Energy Supply Chain in Gastric Carcinogenesis.

BACKGROUND & AIMS: Gastric carcinogenesis develops within a sequential carcinogenic cascade from precancerous metaplasia to dysplasia and adenocarcinoma, and oncogenic gene activation can drive the process. Metabolic reprogramming is considered a key mechanism for cancer cell growth and proliferation. However, how metabolic changes contribute to the progression of metaplasia to dysplasia remains unclear. We have examined metabolic dynamics during gastric carcinogenesis using a novel mouse model that induces Kras activation in zymogen-secreting chief cells. METHODS: We generated a Gif-rtTA;TetO-Cre;KrasG12D (GCK) mouse model that continuously induces active Kras expression in chief cells after doxycycline treatment. Histologic examination and imaging mass spectrometry were performed in the GCK mouse stomachs at 2 to 14 weeks after doxycycline treatment. Mouse and human gastric organoids were used for metabolic enzyme inhibitor treatment. The GCK mice were treated with a stearoyl- coenzyme A desaturase (SCD) inhibitor to inhibit the fatty acid desaturation. Tissue microarrays were used to assess the SCD expression in human gastrointestinal cancers. RESULTS: The GCK mice developed metaplasia and high-grade dysplasia within 4 months. Metabolic reprogramming from glycolysis to fatty acid metabolism occurred during metaplasia progression to dysplasia. Altered fatty acid desaturation through SCD produces a novel eicosenoic acid, which fuels dysplastic cell hyperproliferation and survival. The SCD inhibitor killed both mouse and human dysplastic organoids and selectively targeted dysplastic cells in vivo. SCD was up-regulated during carcinogenesis in human gastrointestinal cancers. CONCLUSIONS: Active Kras expression only in gastric chief cells drives the full spectrum of gastric carcinogenesis. Also, oncogenic metabolic rewiring is an essential adaptation for high-energy demand in dysplastic cells.

CEACAM5 and TROP2 define metaplastic and dysplastic transitions in human antral gastric precancerous lesions and tumors.

BACKGROUND: Mucosal gastric atrophy and intestinal metaplasia (IM) increase the risk for the development of gastric cancer (GC) as they represent a field for development of dysplasia and intestinal-type gastric adenocarcinoma. METHODS: We have investigated the expression of two dysplasia markers, CEACAM5 and TROP2, in human antral IM and gastric tumors to assess their potential as molecular markers. RESULTS: In the normal antral mucosa, weak CEACAM5 and TROP2 expression was only observed in the foveolar epithelium, while inflamed antrum exhibited increased expression of both markers. Complete IM exhibited weak CEACAM5 expression at the apical surface, but no basolateral TROP2 expression. On the other hand, incomplete IM demonstrated high levels of both CEACAM5 and TROP2 expression. Notably, incomplete IM with dysplastic morphology (dysplastic incomplete IM) exhibited higher levels of CEACAM5 and TROP2 expression compared to incomplete IM without dysplastic features (simple incomplete IM). In addition, dysplastic incomplete IM showed diminished SOX2 and elevated CDX2 expression compared to simple incomplete IM. CEACAM5 and TROP2 positivity in incomplete IM was similar to that of gastric adenomas and GC. Significant association was found between CEACAM5 and TROP2 positivity and histology of GC. CONCLUSIONS: These findings support the concept that incomplete IM is more likely associated with GC development. Overall, our study provides evidence of the heterogeneity of gastric IM and the distinct expression profiles of CEACAM5 and TROP2 in dysplastic incomplete IM. Our findings support the potential use of CEACAM5 and TROP2 as molecular markers for identifying individuals with a higher risk of GC development in the context of incomplete IM.

Dynamic tuft cell expansion during gastric metaplasia and dysplasia.

Tuft cells are chemosensory cells associated with luminal homeostasis, immune response, and tumorigenesis in the gastrointestinal tract. We aimed to elucidate alterations in tuft cell populations during gastric atrophy and tumorigenesis in humans with correlative comparison to relevant mouse models. Tuft cell distribution was determined in human stomachs from organ donors and in gastric pathologies including Ménétrier's disease, Helicobacter pylori gastritis, intestinal metaplasia (IM), and gastric tumors. Tuft cell populations were examined in Lrig1-KrasG12D , Mist1-KrasG12D , and MT-TGFα mice. Tuft cells were evenly distributed throughout the entire normal human stomach, primarily concentrated in the isthmal region in the fundus. Ménétrier's disease stomach showed increased tuft cells. Similarly, Lrig1-Kras mice and mice overexpressing TGFα showed marked foveolar hyperplasia and expanded tuft cell populations. Human stomach with IM or dysplasia also showed increased tuft cell numbers. Similarly, Mist1-Kras mice had increased numbers of tuft cells during metaplasia and dysplasia development. In human gastric cancers, tuft cells were rarely observed, but showed positive associations with well-differentiated lesions. In mouse gastric cancer xenografts, tuft cells were restricted to dysplastic well-differentiated mucinous cysts and were lost in less differentiated cancers. Taken together, tuft cell populations increased in atrophic human gastric pathologies, metaplasia, and dysplasia, but were decreased in gastric cancers. Similar findings were observed in mouse models, suggesting that, while tuft cells are associated with precancerous pathologies, their loss is most associated with the progression to invasive cancer.

Peritoneal carcinomatosis with desmoplasia and osseous metaplasia mimicking encapsulating peritoneal sclerosis in a cat: case report.

A 13-year-old neutered male Korean short-hair cat presented with anorexia, lethargy, and a severely distended abdomen, suggestive of ascites. Abdominocentesis yielded serosanguineous fluid. A subsequent diagnostic workup, including blood tests, ascitic fluid analysis, imaging studies [radiography, ultrasound, and computed tomography (CT)], and histopathological examination, was performed to identify the underlying cause. Imaging studies revealed characteristics of encapsulating peritoneal sclerosis (EPS) such as peritoneal thickening, fat stranding, and calcification. During laparotomy, fibrous membranes encapsulating the abdominal organs and ascites were observed, and multiple calcified regions were detected on the abdominal wall. Histopathological analysis confirmed the diagnosis of poorly differentiated invasive malignant neoplasms, which were further classified as carcinomatosis based on positive cytokeratin and negative vimentin immunohistochemistry results. To our knowledge, this is the first report of sclerosing peritoneal carcinomatosis with osseous metaplasia in a cat.

Combined inhibition of Bcl-2 family members and YAP induces synthetic lethality in metastatic gastric cancer with RASA1 and NF2 deficiency.

BACKGROUND: Targetable molecular drivers of gastric cancer (GC) metastasis remain largely unidentified, leading to limited targeted therapy options for advanced GC. We aimed to identify molecular drivers for metastasis and devise corresponding therapeutic strategies. METHODS: We performed an unbiased in vivo genome-wide CRISPR/Cas9 knockout (KO) screening in peritoneal dissemination using genetically engineered GC mouse models. Candidate genes were validated through in vivo transplantation assays using KO cells. We analyzed target expression patterns in GC clinical samples using immunohistochemistry. The functional contributions of target genes were studied through knockdown, KO, and overexpression approaches in tumorsphere and organoid assays. Small chemical inhibitors against Bcl-2 members and YAP were tested in vitro and in vivo. RESULTS: We identified Nf2 and Rasa1 as metastasis-suppressing genes through the screening. Clinically, RASA1 mutations along with low NF2 expression define a distinct molecular subtype of metastatic GC exhibiting aggressive traits. NF2 and RASA1 deficiency increased in vivo metastasis and in vitro tumorsphere formation by synergistically amplifying Wnt and YAP signaling in cancer stem cells (CSCs). NF2 deficiency enhanced Bcl-2-mediated Wnt signaling, conferring resistance to YAP inhibition in CSCs. This resistance was counteracted via synthetic lethality achieved by simultaneous inhibition of YAP and Bcl-2. RASA1 deficiency amplified the Wnt pathway via Bcl-xL, contributing to cancer stemness. RASA1 mutation created vulnerability to Bcl-xL inhibition, but the additional NF2 deletion conferred resistance to Bcl-xL inhibition due to YAP activation. The combined inhibition of Bcl-xL and YAP synergistically suppressed cancer stemness and in vivo metastasis in RASA1 and NF2 co-deficiency. CONCLUSION: Our research unveils the intricate interplay between YAP and Bcl-2 family members, which can lead to synthetic lethality, offering a potential strategy to overcome drug resistance. Importantly, our findings support a personalized medicine approach where combined therapy targeting YAP and Bcl-2, tailored to NF2 and RASA1 status, could effectively manage metastatic GC.

Changes in glucose metabolism among recipients with diabetes 1 year after kidney transplant: a multicenter 1-year prospective study.

Background: Diabetes mellitus is a common and crucial metabolic complication in kidney transplantation. It is necessary to analyze the course of glucose metabolism in patients who already have diabetes after receiving a transplant. In this study, we investigated the changes in glucose metabolism after transplantation, and a detailed analysis was performed on some patients whose glycemic status improved. Methods: The multicenter prospective cohort study was conducted between 1 April 2016 and 31 September 2018. Adult patients (aged 20 to 65 years) who received kidney allografts from living or deceased donors were included. Seventy-four subjects with pre-transplant diabetes were followed up for 1 year after kidney transplantation. Diabetes remission was defined as the results of the oral glucose tolerance test performed one year after transplantation and the presence or absence of diabetes medications. After 1-year post-transplant, 74 recipients were divided into the persistent diabetes group (n = 58) and the remission group (n = 16). Multivariable logistic regression was performed to identify clinical factors associated with diabetes remission. Results: Of 74 recipients, 16 (21.6%) showed diabetes remission after 1-year post-transplant. The homeostatic model assessment for insulin resistance numerically increased in both groups throughout the first year after transplantation and significantly increased in the persistent diabetes group. The insulinogenic index (IGI30) value significantly increased only in the remission group, and the IGI30 value remained low in the persistent diabetes group. In univariate analysis, younger age, newly diagnosed diabetes before transplantation, low baseline hemoglobin A1c, and high baseline IGI30 were significantly associated with remission of diabetes. After multivariate analysis, only newly diagnosed diabetes before transplantation and IGI30 at baseline were associated with remission of diabetes (34.00 [1.192-969.84], P = 0.039, and 17.625 [1.412-220.001], P = 0.026, respectively). Conclusion: In conclusion, some kidney recipients with pre-transplant diabetes have diabetes remission 1 year after transplantation. Our prospective study revealed that preserved insulin secretory function and newly diagnosed diabetes at the time of kidney transplantation were favorable factors for which glucose metabolism did not worsen or improve 1 year after kidney transplantation.

Apposition of Fibroblasts With Metaplastic Gastric Cells Promotes Dysplastic Transition.

BACKGROUND & AIMS: Elements of field cancerization, including atrophic gastritis, metaplasia, and dysplasia, promote gastric cancer development in association with chronic inflammation. However, it remains unclear how stroma changes during carcinogenesis and how the stroma contributes to progression of gastric preneoplasia. Here we investigated heterogeneity of fibroblasts, one of the most important elements in the stroma, and their roles in neoplastic transformation of metaplasia. METHODS: We used single-cell transcriptomics to evaluate the cellular heterogeneity of mucosal cells from patients with gastric cancer. Tissue sections from the same cohort and tissue microarrays were used to identify the geographical distribution of distinct fibroblast subsets. We further evaluated the role of fibroblasts from pathologic mucosa in dysplastic progression of metaplastic cells using patient-derived metaplastic gastroids and fibroblasts. RESULTS: We identified 4 subsets of fibroblasts within stromal cells defined by the differential expression of PDGFRA, FBLN2, ACTA2, or PDGFRB. Each subset was distributed distinctively throughout stomach tissues with different proportions at each pathologic stage. The PDGFRα+ subset expanded in metaplasia and cancer compared with normal, maintaining a close proximity with the epithelial compartment. Co-culture of metaplasia- or cancer-derived fibroblasts with gastroids showing the characteristics of spasmolytic polypeptide-expressing metaplasia-induced disordered growth, loss of metaplastic markers, and increases in markers of dysplasia. Culture of metaplastic gastroids with conditioned media from metaplasia- or cancer-derived fibroblasts also promoted dysplastic transition. CONCLUSIONS: These findings indicate that fibroblast associations with metaplastic epithelial cells can facilitate direct transition of metaplastic spasmolytic polypeptide-expressing metaplasia cell lineages into dysplastic lineages.

Bare-Metal Stent in Dysfunctional Hemodialysis Access: An Assessment of Circuit Patency according to Access Type and Stent Location.

Purpose: To evaluate the circuit patency after nitinol bare-metal stent (BMS) placement according to the type of access and location of the stent in dysfunctional hemodialysis access. Materials and Methods: Between January 2017 and December 2019, 159 patients (mean age, 64.1 ± 13.2 years) underwent nitinol BMS placement for dysfunctional access. The location of stents was as follows: 18 brachiocephalic vein, 51 cephalic arch, 40 upper arm vein, 10 juxta-anastomotic vein, 7 arteriovenous (AV) anastomosis, and 33 graft-vein (GV) anastomosis. Circuit patency was evaluated by the Kaplan-Meier method, and cox regression model. Results: A total of 159 stents were successfully deployed in 103 AV fistula (AVF) and 56 AV graft (AVG). AVG showed lower primary and secondary patency at 12-months compared with AVF (primary patency; 25.0% vs. 44.7%; p = 0.005, secondary patency; 76.8% vs. 92.2%; p = 0.014). Cox regression model demonstrated poorer primary patency at 12 months after stenting in the cephalic arch and GV anastomosis compared with the other sites. Conclusion: AVF showed better primary and secondary circuit patency at 12 months following the placement of BMS compared with AVG. Stents in the cephalic arch and GV anastomosis were associated with poorer primary patency at 12 months compared to those in other locations.

Gut Epithelial Inositol Polyphosphate Multikinase Alleviates Experimental Colitis via Governing Tuft Cell Homeostasis.

BACKGROUND & AIMS: Inositol polyphosphate multikinase (IPMK), an essential enzyme for inositol phosphate metabolism, has been known to mediate major biological events such as growth. Recent studies have identified single-nucleotide polymorphisms in the IPMK gene associated with inflammatory bowel disease predisposition. Therefore, we aimed to investigate the functional significance of IPMK in gut epithelium. METHODS: We generated intestinal epithelial cell (IEC)-specific Ipmk knockout (IPMKΔIEC) mice, and assessed their vulnerability against dextran sulfate sodium-induced experimental colitis. Both bulk and single-cell RNA sequencing were performed to analyze IPMK-deficient colonic epithelial cells and colonic tuft cells. RESULTS: Although IPMKΔIEC mice developed normally and showed no intestinal abnormalities during homeostasis, Ipmk deletion aggravated dextran sulfate sodium-induced colitis, with higher clinical colitis scores, and increased epithelial barrier permeability. Surprisingly, Ipmk deletion led to a significant decrease in the number of tuft cells without influencing other IECs. Single-cell RNA sequencing of mouse colonic tuft cells showed 3 distinct populations of tuft cells, and further showed that a transcriptionally inactive population was expanded markedly in IPMKΔIEC mice, while neuronal-related cells were relatively decreased. CONCLUSIONS: Cholinergic output from tuft cells is known to be critical for the restoration of intestinal architecture upon damage, supporting that tuft cell-defective IPMKΔIEC mice are more prone to colitis. Thus, intestinal epithelial IPMK is a critical regulator of colonic integrity and tissue regeneration by determining tuft cell homeostasis and affecting cholinergic output.

Antithymocyte globulin versus basiliximab induction for kidney transplantation in elderly patients: matched analysis within the Korean multicentric registry.

BACKGROUND: Basiliximab (BSX) and antithymocyte globulins (ATGs), are two major immunosuppressive agents commonly used as induction therapy for kidney transplant (KT) recipients. The superiority of ATG over BSX has not been well established, especially in elderly KT recipients with low immunological risk. METHODS: A total of 847 elderly (≥60 years old), low-risk KT patients in the Korean Organ Transplantation Registry were propensity score-matched at a 1:2 ratio and compared according to ATG or BSX induction therapy. The primary outcome was patient and graft survival and biopsy-proven acute cellular rejection. The secondary outcome was graft function, BK virus nephropathy, infection, cancer, new-onset diabetes mellitus after transplantation (NODAT), and delayed graft function. RESULTS: In total, 165 patients in the ATG group were matched with 298 patients in the BSX group with average ages of 64.3 and 64.2 years, respectively. During a follow-up of 28.5 ± 10.4 months, the cumulative probabilities of death-censored graft failure at 3 years posttransplantation were 1.3% and 1.4% in ATG and BSX groups, respectively, without a significant difference (p = 0.72). The cumulative probability of NODAT at 3 years posttransplantation was significantly higher in the BSX group (35.6% vs. 21.6%, p = 0.02). The median tacrolimus trough level was significantly lower at 6 months after KT in the ATG group (5.7 ng/mL vs. 6.4 ng/mL, p = 0.001). There were no differences in the other evaluated outcomes. CONCLUSION: Compared with BSX, in elderly, low-risk KT patients, ATG reduced tacrolimus and steroid requirements without differences in all-cause mortality, rejection, or infection, resulting in a reduced NODAT incidence.

Up-regulation of Aquaporin 5 Defines Spasmolytic Polypeptide-Expressing Metaplasia and Progression to Incomplete Intestinal Metaplasia.

BACKGROUND & AIMS: Metaplasia in the stomach is highly associated with development of intestinal-type gastric cancer. Two types of metaplasias, spasmolytic polypeptide-expressing metaplasia (SPEM) and intestinal metaplasia (IM), are considered precancerous lesions. However, it remains unclear how SPEM and IM are related. Here we investigated a new lineage-specific marker for SPEM cells, aquaporin 5 (AQP5), to assist in the identification of these 2 metaplasias. METHODS: Drug- or Helicobacter felis (H felis) infection-induced mouse models were used to identify the expression pattern of AQP5 in acute or chronic SPEM. Gene-manipulated mice treated with or without drug were used to investigate how AQP5 expression is regulated in metaplastic lesions. Metaplastic samples from transgenic mice and human gastric cancer patients were evaluated for AQP5 expression. Immunostaining with lineage-specific markers was used to differentiate metaplastic gland characteristics. RESULTS: Our results revealed that AQP5 is a novel lineage-specific marker for SPEM cells that are localized at the base of metaplastic glands initially and expand to dominate glands after chronic H felis infection. In addition, AQP5 expression was up-regulated early in chief cell reprogramming and was promoted by interleukin 13. In humans, metaplastic corpus showed highly branched structures with AQP5-positive SPEM. Human SPEM cells strongly expressing AQP5 were present at the bases of incomplete IM glands marked by TROP2 but were absent from complete IM glands. CONCLUSIONS: AQP5-expressing SPEM cells are present in pyloric metaplasia and TROP2-positive incomplete IM and may be an important component of metaplasia that can predict a higher risk for gastric cancer development.

Programmed Death Ligand 1-Expressing Classical Dendritic Cells MitigateHelicobacter-Induced Gastritis.

BACKGROUND & AIMS: Helicobacter pylori has been reported to modulate local immune responses to colonize persistently in gastric mucosa. Although the induced expression of programmed cell death ligand 1 (PD-L1) has been suggested as an immune modulatory mechanism for persistent infection of H pylori, the main immune cells expressing PD-L1 and their functions in Helicobacter-induced gastritis still remain to be elucidated. METHODS: The blockades of PD-L1 with antibody or PD-L1-deficient bone marrow transplantation were performed in Helicobacter-infected mice. The main immune cells expressing PD-L1 in Helicobacter-infected stomach were determined by flow cytometry and immunofluorescence staining. Helicobacter felis or H pylori-infected dendritic cell (DC)-deficient mouse models including Flt3-/-, Zbtb46-diphtheria toxin receptor, and BDCA2-diphtheria toxin receptor mice were analyzed for pathologic changes and colonization levels. Finally, the location of PD-L1-expressing DCs and the correlation with H pylori infection were analyzed in human gastric tissues using multiplexed immunohistochemistry. RESULTS: Genetic or antibody-mediated blockade of PD-L1 aggravated Helicobacter-induced gastritis with mucosal metaplasia. Gastric classical DCs expressed considerably higher levels of PD-L1 than other immune cells and co-localized with T cells in gastritis lesions from Helicobacter-infected mice and human beings. H felis- or H pylori-infected Flt3-/- or classical DC-depleted mice showed aggravated gastritis with severe T-cell and neutrophil accumulation with low bacterial loads compared with that in control mice. Finally, PD-L1-expressing DCs were co-localized with T cells and showed a positive correlation with H pylori infection in human subjects. CONCLUSIONS: The PD-1/PD-L1 pathway may be responsible for the immune modulatory function of gastric DCs that protects the gastric mucosa from Helicobacter-induced inflammation, but allows persistent Helicobacter colonization.

Cytomegalovirus-Associated Hemophagocytic Syndrome Diagnosed by Liver Biopsy in a Kidney Transplant Recipient.

Hemophagocytic syndrome (HPS) is a rare but potentially life-threatening disease in kidney transplant recipients, and is caused by systemic proliferation of macrophages actively phagocytizing other blood cells in the bone marrow, lymph nodes, and the spleen. Here, we report a 40-year-old male kidney transplant recipient who presented with fever, bicytopenia, and elevated liver enzymes 2 months after transplantation. Given that cytomegalovirus antigenemia and real-time polymerase chain reaction tests were positive, liver biopsy was performed under an assumption of cytomegalovirus-induced hepatitis. Hepatic histology revealed multifocal microabscess with cytomegalovirus inclusion bodies, marked Kupffer cell hyperplasia, and erythrophagocytosis by activated macrophages. As laboratory findings such as hyperferritinemia, elevated serum lactate dehydrogenase, low natural killer cell activity, and high soluble interleukin-2 receptor were also compatible with HPS, the recipient was diagnosed as having cytomegalovirus-induced hepatitis combined with reactive HPS. Following intravenous ganciclovir therapy with continuous administration of tacrolimus and corticosteroid, the symptoms resolved and laboratory findings were normalized. As far as we know, this is the first report of cytomegalovirus-induced hepatitis combined with reactive HPS in a kidney transplant recipient that is diagnosed by liver biopsy.

Insulin Secretion and Insulin Resistance Trajectories over 1 Year after Kidney Transplantation: A Multicenter Prospective Cohort Study.

BACKGROUND: We investigated the changing patterns of insulin secretion and resistance and risk factors contributing to the development of post-transplant diabetes mellitus (PTDM) in kidney recipients under tacrolimus-based immunosuppression regimen during 1 year after transplantation. METHODS: This was a multicenter prospective cohort study. Of the 168 subjects enrolled in this study, we analyzed a total 87 kidney transplant recipients without diabetes which was assessed by oral glucose tolerance test before transplantation. We evaluated the incidence of PTDM and followed up the index of insulin secretion (insulinogenic index [IGI]) and resistance (homeostatic model assessment for insulin resistance [HOMA-IR]) at 3, 6, 9 months, and 1 year after transplantation by oral glucose tolerance test and diabetes treatment. We also assessed the risk factors for incident PTDM. RESULTS: PTDM developed in 23 of 87 subjects (26.4%) during 1 year after transplantation. More than half of total PTDM (56.5%) occurred in the first 3 months after transplantation. During 1 year after transplantation, insulin resistance (HOMA-IR) was increased in both PTDM and no PTDM group. In no PTDM group, the increase in insulin secretory function to overcome insulin resistance was also observed. However, PTDM group showed no increase in insulin secretion function (IGI). Old age, status of prediabetes and episode of acute rejection were significantly associated with the development of PTDM. CONCLUSION: In tacrolimus-based immunosuppressive drugs regimen, impaired insulin secretory function for reduced insulin sensitivity contributed to the development of PTDM than insulin resistance during 1 year after transplantation.

Clinical Study of Standard- vs Reduced-Dose Tacrolimus Combined With Generic Mycophenolate Mofetil in De Novo Kidney Transplantation: A Prospective Randomized Trial.

BACKGROUND: The lowering of calcineurin inhibitor exposure is possibly considered as the proper strategy to prevent calcineurin inhibitor-induced nephrotoxicity in kidney transplant. This clinical study was designed to compare the efficacy and tolerability of reduced-dose tacrolimus with standard-dose mycophenolate mofetil (MMF) vs standard-dose tacrolimus with reduced-dose MMF. METHODS: A prospective, multicenter, open-label, randomized, and parallel-group clinical trial was conducted at 4 transplant centers in Korea. A total sample size was 108, and eligible patients were randomly assigned in a 1:1 ratio to either reduced-dose tacrolimus with standard-dose MMF (the study group) or standard-dose tacrolimus with reduced-dose MMF (the control group) for 6 months in de novo kidney transplant recipients. Graft function, the incidence of efficacy failure, and adverse events were compared. RESULTS: The mean estimated glomerular filtration rate at 6 months post-transplantation was 69.83 ± 16.68 mL/min/1.73 m2 in the study group and 69.92 ± 17.55 mL/min/1.73 m2 in the control group (P > .05). The overall incidence of biopsy-proven acute rejection was 3.64% (n = 2) in the study group, compared to 3.77% (n = 2) in the control group (P > .05). There was no graft loss, death, or loss of follow-up in either group. CONCLUSION: In conclusion, the results suggest that tacrolimus minimization with standard-dose MMF provides adequate immunosuppression with proper renal function and similar rate of incidence of acute rejection compared with the regimen including standard-dose tacrolimus with reduced-dose MMF.

Improvement of medication adherence with simplified once-daily immunosuppressive regimen in stable kidney transplant recipients: A prospective cohort study.

BACKGROUND: Many immunosuppressive drugs are prescribed as twice-daily dosing. A simplified once-daily dosing of immunosuppressive drug regimen may improve medication adherence. We investigated medication adherence of simplified once-daily immunosuppressive regimen consisting of extended-release tacrolimus, sirolimus, and corticosteroids along with the efficacy and safety of this regimen. METHODS: This study was a prospective, multicenter, controlled and cohort trial. Stable kidney transplant recipients who had received transplantation at least 3 months before the study enrollment were eligible for the study. Participants were required to fill-out the self-reported immunosuppressant therapy barrier scale (ITBS) questionnaire before and after the conversion. Other clinical laboratory parameters and adverse events were evaluated until 6 months post-conversion. RESULTS: A total of 160 kidney recipients comprised the intention-to-treat population. The mean total ITBS score was 19.5 ± 4.0 at pre-conversion and 6 months after converting, the mean total ITBS score was 16.6 ± 3.6 (p < 0.001). Particularly, the ITBS scores of 4 questions related to the frequency of medication dosing were significantly different between pre-conversion and post-conversion. Only 1 patient (0.62%) was diagnosed as biopsy-confirmed acute rejection in the study period. There was no significant change in the mean estimated glomerular filtration rate after the conversion. Overall 95 patients (59.4%) had an adverse event and 28 patients (17.5%) had a serious adverse event. No graft loss and 1 death were reported. CONCLUSION: Medication adherence after the conversion to the once-daily immunosuppressive regimen was significantly improved with no additional risks of efficacy failure or adverse events.

In vivo efficacy of combination of colistin with fosfomycin or minocycline in a mouse model of multidrug-resistant Acinetobacter baumannii pneumonia.

Unfortunately, the options for treating multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) infections are extremely limited. Recently, fosfomycin and minocycline were newly introduced as a treatment option for MDR A. baumannii infection. Therefore, we investigated the efficacy of the combination of colistin with fosfomycin and minocycline, respectively, as therapeutic options in MDR A. baumannii pneumonia. We examined a carbapenem-resistant A. baumannii isolated from clinical specimens at Severance Hospital, Seoul, Korea. The effect of colistin with fosfomycin, and colistin with minocycline on the bacterial counts in lung tissue was investigated in a mouse model of pneumonia caused by MDR A. baumannii. In vivo, colistin with fosfomycin or minocycline significantly (p < 0.05) reduced the bacterial load in the lungs compared with the controls at 24 and 48 h. In the combination groups, the bacterial loads differed significantly (p < 0.05) from that with the more active antimicrobial alone. Moreover, the combination regimens of colistin with fosfomycin and colistin with minocycline showed bactericidal and synergistic effects compared with the more active antimicrobial alone at 24 and 48 h. This study demonstrated the synergistic effects of combination regimens of colistin with fosfomycin and minocycline, respectively, as therapeutic options in pneumonia caused by MDR A. baumannii.