Regulation of Pancreatic β Cell Mass by Cross-Interaction between CCAAT Enhancer Binding Protein β Induced by Endoplasmic Reticulum Stress and AMP-Activated Protein Kinase Activity

During the development of type 2 diabetes, endoplasmic reticulum (ER) stress leads to not only insulin resistance but also to pancreatic beta cell failure. Conversely, cell function under various stressed conditions can be restored by reducing ER stress by activating AMP-activated protein kinase (AMPK). However, the details of this mechanism are still obscure. Therefore, the current study aims to elucidate the role of AMPK activity during ER stress-associated pancreatic beta cell failure. MIN6 cells were loaded with 5-amino-1-ϐ-D-ribofuranosyl-imidazole-4-carboxamide (AICAR) and metformin to assess the relationship between AMPK activity and CCAAT enhancer binding protein ϐ (C/EBPϐ) expression levels. The effect of C/EBPϐ phosphorylation on expression levels was also investigated. Vildagliptin and metformin were administered to pancreatic beta cell-specific C/EBPϐ transgenic mice to investigate the relationship between C/EBPϐ expression levels and AMPK activity in the pancreatic islets. When pancreatic beta cells are exposed to ER stress, the accumulation of the transcription factor C/EBPϐ lowers the AMP/ATP ratio, thereby decreasing AMPK activity. In an opposite manner, incubation of MIN6 cells with AICAR or metformin activated AMPK, which suppressed C/EBPϐ expression. In addition, administration of the dipeptidyl peptidase-4 inhibitor vildagliptin and metformin to pancreatic beta cell-specific C/EBPϐ transgenic mice decreased C/EBPϐ expression levels and enhanced pancreatic beta cell mass in proportion to the recovery of AMPK activity. Enhanced C/EBPϐ expression and decreased AMPK activity act synergistically to induce ER stress-associated pancreatic beta cell failure

Committee report : Questionnaire survey on the treatment of COVID-19 in patients receiving dialysis therapy

Background: Patients with coronavirus disease 2019 (COVID-19) who receive dialysis therapy develop more severe disease and have a poorer prognosis than patients who do not. Although various data on the treatment of patients not receiving dialysis therapy have been reported, clinical practice for patients on dialysis is challenging as data is limited. The Infection Control Committee of the Japanese Society for Dialysis Therapy decided to clarify the status of treatment in COVID-19 patients on dialysis. Methods: A questionnaire survey of 105 centers that had treated at least five COVID-19 patients on dialysis was conducted in August 2021. Results: Sixty-six centers (62.9%) responded to the questionnaire. Antivirals were administered in 27.7% of facilities treating mild disease (most patients received favipiravir) and 66.7% of facilities treating moderate disease (most patients with moderate or more severe conditions received remdesivir). Whether and how remdesivir is administered varies between centers. Steroids were initiated most frequently in moderate II disease (50.8%), while 43.1% of the facilities initiated steroids in mild or moderate I disease. The type of steroid, dose, and the duration of administration were generally consistent, with most facilities administering dexamethasone 6 mg orally or 6.6 mg intravenously for 10 days. Steroid pulse therapy was administered in 48.5% of the facilities, and tocilizumab was administered in 25.8% of the facilities, mainly to patients on ventilators or equivalent medications, or to the cases of exacerbations. Furthermore, some facilities used a polymethylmethacrylate membrane during dialysis, nafamostat as an anticoagulant, and continuous hemodiafiltration in severe cases. There was limited experience of polymyxin B-immobilized fiber column-direct hemoperfusion and extracorporeal membrane oxygenation. The discharge criteria for patients receiving dialysis therapy were longer than those set by the Ministry of Health, Labor and Welfare in 22.7% of the facilities. Conclusions: Our survey revealed a variety of treatment practices in each facility. Further evidence and innovations are required to improve the prognosis of patients with COVID-19 receiving dialysis therapy

Investigation for the efficacy of COVID-19 vaccine in Japanese CKD patients treated with hemodialysis

Background: Dialysis patients are predisposed to severe disease and have a high mortality rate in coronavirus disease 2019 (COVID-19) due to their comorbidities and immunocompromised conditions. Therefore, dialysis patients should be prioritized for vaccination. This study aimed to examine how long the effects of the vaccine are maintained and what factors affect antibody titers. Methods: Hemodialysis patients (HD group) and age- and sex-matched non-dialysis individuals (Control group), receiving two doses of BNT162b2 vaccine, were recruited through the Japanese Society for Dialysis Therapy (JSDT) Web site in July 2021. Anti-SARS-CoV-2 immunoglobulin (IgG) (SARS-CoV-2 IgG titers) was measured before vaccination, 3 weeks after the first vaccination, 2 weeks after the second vaccination, and 3 months after the second vaccination, and was compared between Control group and HD group. Factors affecting SARS-CoV-2 IgG titers were also examined using multivariable regression analysis and stepwise regression analysis (least AIC). In addition, we compared adverse reactions in Control and HD groups and examined the relationship between adverse reactions and SARS-CoV-2 IgG titers. Results: Our study enrolled 123 participants in the Control group (62.6% men, median age 67.0 years) and 206 patients in the HD group (64.1% men, median age 66.4 years). HD group had significantly lower SARS-CoV-2 IgG titers at 3 weeks after the first vaccination (p < 0.0001), 2 weeks after second vaccination (p = 0.0002), and 3 months after the second vaccination (p = 0.045) than Control group. However, the reduction rate of SARS-CoV-2 IgG titers between 2 weeks and 3 months after the second vaccination was significantly smaller in HD group than in Control (p = 0.048). Stepwise regression analysis revealed that dialysis time was identified as the significant independent factors for SARS-CoV-2 IgG titers at 2 weeks after the second vaccination in HD group (p = 0.002) and longer dialysis time resulted in higher maximum antibody titers. The incidences of fever and nausea after the second vaccination were significantly higher in the HD group (p = 0.039 and p = 0.020). Antibody titers in those with fever were significantly higher than those without fever in both groups (HD: p = 0.0383, Control: p = 0.0096). Conclusion: HD patients had significantly lower antibody titers than age- and sex-matched non-dialysis individuals over 3 months after vaccination. Dialysis time was identified as a factor affecting SARS-CoV-2 IgG titers in HD group, with longer dialysis time resulting in higher maximum SARS-CoV-2 IgG titers

T-Cell Response and Antibody Production Induced by the COVID-19 Booster Vaccine in Japanese Chronic Kidney Disease Patients Treated with Hemodialysis

Humoral and cellular responses are critical in understanding immune responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. Here, we evaluated these responses in hemodialysis (HD) patients after the booster vaccination. SARS-CoV-2 immunoglobulin (IgG) levels, neutralizing antibody titers, and the T-SPOT®.COVID test (T-SPOT) were measured prior to, three weeks after, and three months after the booster administration. The HD group had significantly higher SARS-CoV-2 IgG levels and neutralizing antibody titers against the original strain at three weeks and three months after the booster vaccination compared to the control group, albeit the HD group had lower SARS-CoV-2 IgG levels and neutralizing antibody titers before the booster administration. Moreover, the HD group had significantly higher T-SPOT levels at all three time points compared to the control group. The HD group also had significantly higher local and systemic adverse reaction rates than the control group. By booster vaccination, HD patients could acquire more effective SARS-CoV-2-specific humoral and cellular immunity than the control group

Ablation of TSC2 Enhances Insulin Secretion by Increasing the Number of Mitochondria through Activation of mTORC1

) mice. The present study examines the effects of TSC2 ablation on insulin secretion from pancreatic beta cells. mice and TSC2 knockdown insulin 1 (INS-1) insulinoma cells treated with small interfering ribonucleic acid were used to investigate insulin secretion, ATP content and the expression of mitochondrial genes. mice exhibit hyperinsulinemia due to an increase in the number of mitochondria as well as enlargement of individual beta cells via activation of mTORC1.Activation of mTORC1 by TSC2 ablation increases mitochondrial biogenesis and enhances insulin secretion from pancreatic beta cells

Early administration of dapagliflozin preserves pancreatic β‐cell mass through a legacy effect in a mouse model of type 2 diabetes

Abstract Aims/Introduction The preservation of pancreatic β‐cell mass is an essential factor in the onset and development of type 2 diabetes mellitus. Recently, sodium–glucose cotransporter 2 inhibitors have been launched as antihyperglycemic agents, and their organ‐protective effects are attracting attention. They are also reported to have favorable effects on the preservation of pancreatic β‐cell mass, but the appropriate timing for the administration of sodium–glucose cotransporter 2 inhibitors is obscure. Materials and Methods In the present study, we administered a sodium–glucose cotransporter 2 inhibitor, dapagliflozin, to an animal model of type 2 diabetes mellitus, db/db mice, and investigated the adequate timing and duration for its administration. We also carried out microarray analysis using pancreatic islets from db/db mice. Results We found that dapagliflozin preserved pancreatic β‐cell mass depending on the duration of administration and markedly improved blood glucose levels. If the duration was the same, the earlier administration of dapagliflozin was more effective in preserving pancreatic β‐cell mass, increasing serum insulin levels and improving blood glucose levels. From microarray analysis, we discovered that the expression of Agr2, Tff2 and Gkn3 was significantly upregulated after the early administration of dapagliflozin. This upregulated gene expression might provide a legacy effect for the preservation of pancreatic β‐cell mass. Conclusions We expect that the early administration of dapagliflozin would provide a long‐lasting effect in preserving pancreatic β‐cell mass

Docosahexaenoic Acid Reduces Palmitic Acid-Induced Endoplasmic Reticulum Stress in Pancreatic Β Cells

Abstract: Endoplasmic reticulum (ER) stress leads to peripheral insulin resistance and the progression of pancreatic beta cell failure in type 2 diabetes. Although ER stress plays an important role in the pathogenesis of diabetes, it is indispensable for cellular activity. Therefore, when assessing the pathological significance of ER stress, it is important to monitor and quantify ER stress levels. Here, we have established a novel system to monitor ER stress levels quickly and sensitively, and using this method, we have clarified the effect of differences in glucose concentration and various fatty acids on the ER of pancreatic β cells. First, we developed a cell system that secretes Gaussia luciferase in culture medium depending on the activation of the GRP78 promoter. This system could sensitively monitor ER stress levels that could not be detected with real-time RT-PCR and immunoblotting. This system revealed that hyperglycemia does not induce unfolded protein response (UPR) in a short period of time in MIN6 cells, a mouse pancreatic β cell line. Physiological concentrations of palmitic acid, a saturated fatty acid, induced ER stress quickly, while physiological concentrations of oleic acid, an unsaturated fatty acid, did not. Docosahexaenoic acid, an n-3 unsaturated fatty acid, inhibited palmitic acid-induced ER stress. In this study, we have established a system that can sensitively detect ER stress levels of living cells in a short period of time. This system can be used to monitor the state of the ER in living cells and lead to the investigation of the significance of physiological or pathological ER stress levels

Acceptance situation of HIV patients in Japanese dialysis facilities—questionnaire survey by the Infection Survey Subcommittee

Abstract Background A newspaper article in August 2016 reported that about 40 medical facilities refused dialysis to a human immunodeficiency virus (HIV) patient. Infection Survey Subcommittee in the Japanese Society for Dialysis Therapy investigated this situation. Methods An anonymous questionnaire survey about the acceptance of HIV-positive patients was sent to 4039 dialysis institutions. The questionnaire included a number of HIV-positive patients on dialysis currently and in the last 5 years, details on whether the institution received requests to perform dialysis on HIV-positive patients, the responses to these requests, the preparation system for acceptance, the reasons for refusal of dialysis of HIV-positive patients, knowledge of HIV-related guidelines in use, and the considerations for the acceptance of dialysis for HIV-positive patients. We evaluated answers to these questions from the institutions. Results Two thousand five hundred eighty-three facilities (64.0%) responded to the survey questions. In the past 5 years, 215 facilities (8.3%) were requested to accept HIV patients for dialysis and 40.1% of these refused acceptance. Although manuals, written policy and procedure, for a needle piercing accident existed in most of the facilities that accepted the patients, many facilities did neither prepare the stocks of anti-HIV drugs nor cooperate with HIV core hospitals. Principal reasons for the refusal were listed as the lack of medical experience with HIV patients, anxiety of healthcare providers with regard to HIV infection risk, lack of stocks of anti-HIV drugs for needle piercing accidents, and the lack of cooperation with HIV core hospitals. The proportion of facilities expected to accept HIV patients in the future was as low as 16.9% among all facilities that responded to the survey. Conclusions The Japanese Society for Dialysis Therapy will need to strengthen the cooperation with other academic societies and disseminate basic knowledge on HIV and infection control measures to develop and establish the acceptance system of maintenance dialysis for HIV patients