Decreased AdipoR1 signaling and its implications for obesity-induced male infertility.

Obesity is among the risk factors for male infertility. Although several mechanisms underlying obesity-induced male subfertility have been reported, the entire mechanism of obesity-induced male infertility still remains unclear. Here, we show that sperm count, sperm motility and sperm fertilizing ability were decreased in male mice fed a high-fat diet and that the expression of the AdipoR1 gene and protein was decreased, and the expression of pro-apoptotic genes and protein increased, in the testis from mice fed a high-fat diet. Moreover, we demonstrate that testes weight, sperm count, sperm motility and sperm fertilizing ability were significantly decreased in AdipoR1 knockout mice compared to those in wild-type mice; furthermore, the phosphorylation of AMPK was decreased, and the expression of pro-apoptotic genes and proteins, caspase-6 activity and pathologically apoptotic seminiferous tubules were increased, in the testis from AdipoR1 knockout mice. Furthermore, study findings show that orally administrated AdipoRon decreased caspase-6 activity and apoptotic seminiferous tubules in the testis, thus ameliorating sperm motility in male mice fed a high-fat diet. This was the first study to demonstrate that decreased AdipoR1/AMPK signaling led to increased caspase-6 activity/increased apoptosis in the testis thus likely accounting for male infertility.

Association Between Vonoprazan and the Risk of Gastric Cancer After Helicobacter pylori Eradication.

BACKGROUND & AIMS: Potassium-competitive acid blockers (PCABs) have been increasingly used to treat upper gastrointestinal disorders, replacing proton pump inhibitors (PPIs). Whereas PPIs are associated with an increased risk of gastric cancer (GC) after Helicobacter pylori (Hp) eradication, it is uncertain whether PCABs carry the same risk. METHODS: Using a population-based claims database in Japan, we identified patients who were prescribed a clarithromycin-based first regimen of Hp eradication between 2015 and 2018. Patients who failed this regimen and those diagnosed with GC before or within 1 year after Hp eradication were excluded. We compared GC incidence between PCAB users and histamine type-2 receptor antagonist (H2RA) users, matching them on the basis of propensity scores calculated with considerations for age, sex, smoking, alcohol consumption, comorbidities, and co-administered medications. PCABs included only vonoprazan in this study. RESULTS: Among 54,055 patients, 568 (1.05%) developed GC during the follow-up period (mean, 3.65 years). The cumulative incidence of GC was 1.64% at 3 years, 2.02% at 4 years, and 2.36% at 5 years in PCAB users and 0.71% at 3 years, 1.04% at 4 years, and 1.22% at 5 years in H2RA users. The use of PCABs was associated with a higher GC risk (matched hazard ratio, 1.92; 95% confidence interval, 1.13-3.25; P = .016). Longer PCAB use and high-dose PCAB use were significantly associated with higher incidence of GC. Sensitivity analyses showed the risk of GC incidence among PCAB users was comparable with that of PPI users. CONCLUSIONS: The use of PCABs was associated with an increased risk of GC among Hp-eradicated patients, with duration/dose response effects.

Increased expression of TNFRSF14 and LIGHT in biliary epithelial cells of patients with primary sclerosing cholangitis.

BACKGROUND AND AIMS: There is a lack of biliary epithelial molecular markers for primary sclerosing cholangitis (PSC). We analyzed candidates from disease susceptibility genes identified in recent genome-wide association studies (GWAS). METHODS: Expression levels of GWAS genes were analyzed in archival liver tissues of patients with PSC and controls. Immunohistochemical analysis was performed to evaluate expression levels in the biliary epithelia of PSC (N = 45) and controls (N = 12). Samples from patients with primary biliary cholangitis (PBC) were used as disease controls (N = 20). RESULTS: Hepatic expression levels of ATXN2, HHEX, PRDX5, MST1, and TNFRSF14 were significantly altered in the PSC group. We focused on the immune-related receptor, TNFRSF14. Immunohistochemistry revealed that high expression of TNFRSF14 in biliary epithelial cells was observed only in the PSC group. In addition, the expression of LIGHT, which encodes a TNFRSF14-activating ligand, was increased in PSC liver. Immunohistochemistry showed that high expression of LIGHT was more common in PSC biliary epithelia (53%) than in the PBC (15%) or control (0%) groups; moreover, it was positively associated with fibrotic progression, although it was not an independent prognostic factor. CONCLUSIONS: TNFRSF14 and LIGHT are promising candidate markers for PSC.

Hepatic FASN deficiency differentially affects nonalcoholic fatty liver disease and diabetes in mouse obesity models.

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes are interacting comorbidities of obesity, and increased hepatic de novo lipogenesis (DNL), driven by hyperinsulinemia and carbohydrate overload, contributes to their pathogenesis. Fatty acid synthase (FASN), a key enzyme of hepatic DNL, is upregulated in association with insulin resistance. However, the therapeutic potential of targeting FASN in hepatocytes for obesity-associated metabolic diseases is unknown. Here, we show that hepatic FASN deficiency differentially affects NAFLD and diabetes depending on the etiology of obesity. Hepatocyte-specific ablation of FASN ameliorated NAFLD and diabetes in melanocortin 4 receptor-deficient mice but not in mice with diet-induced obesity. In leptin-deficient mice, FASN ablation alleviated hepatic steatosis and improved glucose tolerance but exacerbated fed hyperglycemia and liver dysfunction. The beneficial effects of hepatic FASN deficiency on NAFLD and glucose metabolism were associated with suppression of DNL and attenuation of gluconeogenesis and fatty acid oxidation, respectively. The exacerbation of fed hyperglycemia by FASN ablation in leptin-deficient mice appeared attributable to impairment of hepatic glucose uptake triggered by glycogen accumulation and citrate-mediated inhibition of glycolysis. Further investigation of the therapeutic potential of hepatic FASN inhibition for NAFLD and diabetes in humans should thus consider the etiology of obesity.

Comparison of Weight Reduction, Change in Parameters and Safety of a Very Low Carbohydrate Diet in Comparison to a Low Carbohydrate Diet in Obese Japanese Subjects with Metabolic Disorders.

Recently, low-carbohydrate diets (LCDs) have gained worldwide attention. LCDs are potentially effective for Japanese overweight and obese individuals with metabolic disorders. However, few randomized trials of LCDs have focused on the difference between LCDs and VLCDs. We conducted a randomized, prospective study of 42 Japanese, obese adults aged 28-65 years to evaluate the efficacy and safety of LCD and VLCD. To ensure the accuracy of the study, all test meals were provided, and compliance was checked using a smartphone app. Body composition measurements and blood tests were performed before and after the 2-month dietary intervention. The results showed that both methods significantly reduced body weight and fat, and also improved lipid abnormalities and liver function. In the current study, the reductions in weight and fat were comparable. The results of a questionnaire at the end of the study indicated that the LCD was easier to carry out than the VLCD, suggesting that the LCD was sustainable. The present study was unique in that it was a randomized, prospective study of Japanese subjects and that accurate data were obtained by providing meals.

Association of glucagon-like peptide-1 receptor agonist treatment with gastric residue in an esophagogastroduodenoscopy.

AIMS/INTRODUCTION: Previous studies have reported that the glucagon-like peptide-1 receptor agonist (GLP-1RA) delays gastric emptying, and gastric emptying was assessed by the 13 C breath test or paracetamol absorption technique. However, neither of them is clinically familiar in real-world clinical practice. The purpose of the present study was to investigate the association between GLP-1RA treatment and gastric residue in an esophagogastroduodenoscopy. MATERIALS AND METHODS: This study was a matched pair case-control study. The study population consisted of 1,128 individuals with diabetes who had esophagogastroduodenoscopy at our clinic between July 2020 and June 2022. To account for differences in characteristics, such as age, sex, insulin treatment and glycated hemoglobin, we carried out a one-to-one nearest neighbor propensity score matching analysis between diabetes patients with and without GLP-1RA treatment. After matching, we compared the presence of gastric residue in an esophagogastroduodenoscopy by the McNemar test between patients with and without GLP-1RA treatment. RESULTS: After the propensity score matching, we selected 205 pairs. In the propensity score-matched comparison, the proportion of gastric residue was statistically significantly higher in the GLP-1RA treatment group (0.49% vs 5.4%, P = 0.004). The details of GLP-1RA prescribed for the 11 patients with gastric residue were liraglutide once daily 1.8 mg (n = 2), dulaglutide once weekly 0.75 mg (n = 5), semaglutide once weekly 0.5 mg (n = 2) and semaglutide once weekly 1.0 mg (n = 2). CONCLUSION: GLP-1RA treatment is associated with gastric residue in an esophagogastroduodenoscopy in patients with diabetes.

The transcription factor ATF3 switches cell death from apoptosis to necroptosis in hepatic steatosis in male mice.

Hepatocellular death increases with hepatic steatosis aggravation, although its regulation remains unclear. Here we show that hepatic steatosis aggravation shifts the hepatocellular death mode from apoptosis to necroptosis, causing increased hepatocellular death. Our results reveal that the transcription factor ATF3 acts as a master regulator in this shift by inducing expression of RIPK3, a regulator of necroptosis. In severe hepatic steatosis, after partial hepatectomy, hepatic ATF3-deficient or -overexpressing mice display decreased or increased RIPK3 expression and necroptosis, respectively. In cultured hepatocytes, ATF3 changes TNFα-dependent cell death mode from apoptosis to necroptosis, as revealed by live-cell imaging. In non-alcoholic steatohepatitis (NASH) mice, hepatic ATF3 deficiency suppresses RIPK3 expression and hepatocellular death. In human NASH, hepatocellular damage is correlated with the frequency of hepatocytes expressing ATF3 or RIPK3, which overlap frequently. ATF3-dependent RIPK3 induction, causing a modal shift of hepatocellular death, can be a therapeutic target for steatosis-induced liver damage, including NASH.

Association of self-stigma with glycated hemoglobin: A single-center, cross-sectional study of adults with type 1 diabetes in Japan.

AIMS/INTRODUCTION: There has been an increase in research on diabetes-related stigma and its association with glycated hemoglobin (HbA1c) over the past years. However, little is known about the association of self-stigma with HbA1c in persons with type 1 diabetes. This study aims to examine the association between self-stigma and HbA1c in Japanese people with type 1 diabetes. MATERIALS AND METHODS: This cross-sectional study was conducted at a clinic in Tokyo. Questionnaires using nine items from the Japanese version of the Self-Stigma Scale was distributed to outpatients with type 1 diabetes, aged ≥18 years. We excluded outpatients with serious mental disorder, those who required urgent medical treatment or received hemodialysis. Adjusted linear regression analyses tested the association between the score of the 9-item Self-Stigma Scale and HbA1c. RESULTS: Questionnaires were distributed to 166 eligible participants. A total of 109 participants were included in the final analysis after excluding participants with incomplete answers and laboratory data. After adjusting for age, sex, employment status, body mass index, duration of diabetes and insulin secretion, there was a significant positive association between self-stigma and HbA1c (ß = 0.05, 95% confidence interval 0.01 to 0.08). CONCLUSIONS: This cross-sectional study showed a significant association between self-stigma and HbA1c in persons with type 1 diabetes. Addressing self-stigma might be as equally essential as measuring HbA1c in evaluating glycemic outcome among individuals with type 1 diabetes.

Clinical features and sulfonylurea usage among outpatients with diabetes aged ≥90 years in an urban diabetes clinic in Tokyo.

AIMS/INTRODUCTION: Aging of society is accelerating in many countries. The purpose of this study was to describe the clinical features and sulfonylurea usage among diabetes outpatients aged ≥90 years (nonagenarians). MATERIALS AND METHODS: This study was a retrospective observational study. The study population consisted of 69 nonagenarian diabetes outpatients and 857 diabetes outpatients aged <90 years. Patients were classified into four groups: group 1, <65 years; group 2, 65-74 years; group 3, 75-89 years; and group 4, ≥90 years. The presence of hypoglycemic episodes was defined as having self-reported symptoms, or self-monitored or clinically measured blood glucose level <70 mg/dL. RESULTS: The median glycated hemoglobin (HbA1c) in group 1 and group 4 was 7.0% and 7.2%, respectively (P = 0.506). The proportion of sulfonylurea treatment in group 4 was 45.5%, which is significantly higher compared with the other three groups (20.0-27.8%, P < 0.001). In group 4, there was no difference between patients with or without sulfonylurea in age, sex, body mass index, HbA1c and number of antihyperglycemic agents. Five out of 25 nonagenarian sulfonylurea-treated patients had hypoglycemic episodes within the last 2 years, their HbA1c were all 7.0 ≤ HbA1c < 8.0, and sulfonylurea or insulin was tapered in all cases after confirming hypoglycemia. Tapering dosage was attempted in all 25 sulfonylurea-treated nonagenarian patients, but 15 needed to continue sulfonylurea for glycemic control, and 10 continued sulfonylurea with unknown reasons from their medical records. CONCLUSIONS: Although tapering the dosage of sulfonylurea was attempted in nonagenarian patients, sulfonylurea was widely continued for glycemic control. Reverse clinical inertia may exist in some sulfonylurea-treated nonagenarian patients.

Substitution of telemedicine for clinic visit during the COVID-19 pandemic of 2020: Comparison of telemedicine and clinic visit.

AIMS/INTRODUCTION: The purpose of this retrospective observational cohort study was to compare outpatient diabetes care and glycated hemoglobin (HbA1c) level during the coronavirus disease 2019 pandemic in 2020 with 2019, and to compare the glucose-lowering effect of telemedicine and clinic visits during the state of emergency in Japan declared from 7 April to 25 May (inter-period) 2020. MATERIALS AND METHODS: A total of 13 weeks before and after the inter-period were designated as the pre-period and post-period, respectively. The number of study participants who had clinic visits during the pre-period and the post-period were 3,333 in 2020 and 3,608 in 2019. Propensity score matching was carried out to compare the effect of telemedicine and clinic visits on diabetes control in 2020 among diabetes patients with insufficient glucose control (HbA1c ≥7%). The primary outcome was post-period HbA1c. RESULTS: The major difference between 2020 and 2019 was the use of telemedicine in 2020. After adjustment for age, sex, diabetes type, pre-period HbA1c and pre-period body mass index, glycemic control evaluated by HbA1c was significantly worse in the post-period of 2020 than 2019. In the propensity score-matched 618 pairs, the clinic visit group had significantly better post-period HbA1c than the telemedicine group (7.5% vs 7.4%, P = 0.023). CONCLUSIONS: Glycemic control was slightly, but significantly, worse in 2020 than 2019. Although telemedicine significantly improved glycemic control during the coronavirus disease 2019 pandemic in 2020, clinic visits improved HbA1c significantly more. The substitution of telemedicine for clinic visits appears to be a viable option under emergency conditions, but clinic visits might be a better option when possible.

Synergistic association of the copper/zinc ratio under inflammatory conditions with diabetic kidney disease in patients with type 2 diabetes: The Asahi Diabetes Complications Study.

AIMS/INTRODUCTION: We aimed to study the relationships among the copper (Cu)/zinc (Zn) ratio, inflammatory biomarkers, and the prevalence of diabetic kidney disease (DKD) in patients with type 2 diabetes. MATERIALS AND METHODS: A cross-sectional study was performed on 651 patients with type 2 diabetes. DKD was defined as a urinary albumin-to-creatinine ratio of ≥30 mg/g creatinine and/or an estimated glomerular filtration rate using cystatin C of < 60 mL/min/1.73 m2 . Areas under the curves (AUCs), cutoff values, and thresholds for detecting DKD were determined for the Cu/Zn ratio, soluble tumor necrosis factor-α receptor 1 (sTNFαR1), and high-sensitivity C-reactive protein (hsCRP). Patients were categorized by each cutoff value of sTNFαR1 and the Cu/Zn ratio. Odds ratios (ORs) and biological interactions for the prevalence of DKD were determined. RESULTS: DKD was identified in 220 patients. AUC/optimal cutoff values were 0.777/1300 pg/mL for sTNFαR1, 0.603/1.1648 for the Cu/Zn ratio, and 0.582/305 ng/mL for hsCRP. The ORs for DKD were higher, but not significantly, in the sTNFαR1 < 1300 and Cu/Zn ≥ 1.1648 group, significantly higher in the sTNFαR1 ≥ 1300 and Cu/Zn < 1.1648 group (P < 0.0001), and further synergistically elevated in the sTNFαR1 ≥ 1300 and Cu/Zn ≥ 1.1648 group (P < 0.0001) compared with the sTNFαR1 < 1300 and Cu/Zn < 1.1648 group after multivariable adjustment. Levels of sTNFαR1 were significantly higher in the sTNFαR1 ≥ 1300 and Cu/Zn ≥ 1.1648 group than in the sTNFαR1 ≥ 1300 and Cu/Zn < 1.1648 group (P = 0.0006). CONCLUSIONS: Under an inflammatory initiation signal of elevated serum sTNFαR1 levels, an increase in the Cu/Zn ratio may further exacerbate inflammation and is synergistically associated with a high prevalence of DKD in patients with type 2 diabetes.

Diabetes management by either telemedicine or clinic visit improved glycemic control during the coronavirus disease 2019 pandemic state of emergency in Japan.

The purpose of this retrospective cohort study at a Tokyo diabetes clinic was to evaluate the effect of telemedicine and clinic visit on glycated hemoglobin (HbA1c) during the coronavirus disease 2019 state of emergency. The effect of telemedicine and clinic visit during the emergency period on the post-emergency measured HbA1c was evaluated by multiple regression models and logistic regression models adjusted for age, sex, type of diabetes, pre-emergency HbA1c and body mass index, and body mass index change during the emergency period. Among 2,727 patients who visited the clinic before and after the emergency period, the interval between clinic visits during the emergency period was significantly associated with HbA1c improvement. Telemedicine and clinic visit were independently associated with HbA1c improvement when pre-emergency HbA1c was ≥7%. In conclusion, clinic visit and telemedicine during the coronavirus disease 2019 emergency period were both independently effective in HbA1c improvement in Japanese diabetes patients who had insufficient HbA1c control.

Association of insulin treatment with gastric residue during an esophagogastroduodenoscopy.

The purpose of this study was to investigate the association of glycemic control and diabetes treatment to gastric residue observed during an esophagogastroduodenoscopy. Among 6,592 individuals who had esophagogastroduodenoscopy at our clinic between 2003 and 2019, we retrospectively and longitudinally identified those who had gastric residue during an esophagogastroduodenoscopy. Other data collected were age, sex, diagnosis of diabetes, glycated hemoglobin and diabetes medication. Cox proportional hazards models were used to assess the association of these data with the occurrence of gastric residue. To the best of our knowledge, this is the first retrospective cohort study finding that undergoing insulin treatment is a risk factor for gastric residue independent of age, sex and diabetes or glycated hemoglobin.

Hepatocellular carcinoma development in diabetic patients: a nationwide survey in Japan.

BACKGROUND: Although type 2 diabetes mellitus (T2DM) is a known risk factor for hepatocellular carcinoma (HCC) development, the annual incidence in diabetes patients is far below the threshold of efficient surveillance. This study aimed to elucidate the risk factors for HCC in diabetic patients and to determine the best criteria to identify surveillance candidates. METHODS: The study included 239 patients with T2DM who were diagnosed with non-viral HCC between 2010 and 2015, with ≥ 5 years of follow-up at diabetes clinics of 81 teaching hospitals in Japan before HCC diagnosis, and 3277 non-HCC T2DM patients from a prospective cohort study, as controls. Clinical data at the time of and 5 years before HCC diagnosis were collected. RESULTS: The mean patient age at HCC diagnosis was approximately 73 years, and 80% of the patients were male. The proportion of patients with insulin use increased, whereas the body mass index (BMI), proportion of patients with fatty liver, fasting glucose levels, and hemoglobin A1c (HbA1c) levels decreased significantly in 5 years. In the cohort study, 18 patients developed HCC during the mean follow-up period of 4.7 years with an annual incidence of 0.11%. Multivariate logistic regression analyses showed that the FIB-4 index was an outstanding predictor of HCC development along with male sex, presence of hypertension, lower HbA1c and albumin levels, and higher BMI and gamma-glutamyl transpeptidase levels. Receiver-operating characteristic analyses showed that a FIB-4 cut-off value of 3.61 could help identify high-risk patients, with a corresponding annual HCC incidence rate of 1.1%. CONCLUSION: A simple calculation of the FIB-4 index in diabetes clinics can be the first step toward surveillance of HCC with a non-viral etiology.

Thresholds for postprandial hyperglycemia and hypertriglyceridemia associated with increased mortality risk in type 2 diabetes patients: A real-world longitudinal study.

AIMS/INTRODUCTION: To identify thresholds for postprandial hyperglycemia and hypertriglyceridemia predictive of all-cause mortality in patients with type 2 diabetes. MATERIALS AND METHODS: A total of 1,928 patients with type 2 diabetes visited our clinic for the first time from 1995 to 1999 and were followed up for ≥1 year. During the first year, 2-h post-breakfast blood glucose (2h-BG) levels were measured in 1,122 patients (BG cohort) and postprandial serum triglyceride (ppTG) levels were measured in 1,826 patients (TG cohort). Patients were retrospectively followed until 2017 and administered questionnaires. Associations between 2h-BG and ppTG levels and mortality risk were assessed by the multivariate Cox regression analysis. RESULTS: Over of 17,429 person-years, 162 deaths occurred in the BG cohort, and over 28,026 person-years, 253 deaths occurred in the TG cohort. Hazard ratios (HRs) with 95% confidence intervals for all-cause mortality per 1-standard deviation increases in 2h-BG and ppTG were 1.34 (1.08-1.67) and 1.24 (1.06-1.45), respectively. HRs showed increasing trends across quintiles of 2h-BG (P = 0.034) and ppTG (P = 0.007). The HR was significantly elevated (2.37, 1.26-4.47) in the fifth quintile of 2h-BG (≥13.8 mmol/L) compared with the first quintile (<7.0 mmol/L; P = 0.008). The HR was also significantly elevated (1.63, 1.03-2.60) in the fifth quintile of ppTG (≥2.30 mmol/L) compared with the first quintile (<0.91 mmol/L; P = 0.038). CONCLUSIONS: Postprandial hyperglycemia and hypertriglyceridemia were associated with all-cause mortality in patients with type 2 diabetes. We propose thresholds of 13.8 mmol/L 2h-BG and 2.30 mmol/L ppTG to identify patients at increased risk of mortality.

5-Aminolevulinic acid-mediated photodynamic activity in patient-derived cholangiocarcinoma organoids.

BACKGROUND: Accurate diagnosis of the disease extension of cholangiocarcinoma (CCA) is often difficult in clinical practice. The diagnostic yield of conventional pre-operative imaging or endoscopic procedures is sometimes insufficient for the evaluation of longitudinal spreading of CCA. Here we investigated the usefulness of 5-aminolevulinic acid (5-ALA) for the pre- or intra-operative diagnosis of CCA, using patient-derived organoids. METHODS: Four CCA- and two adjacent tissue-derived organoids were established. After 5-ALA treatment, we assessed their photodynamic activity using fluorescence microscopy. RESULTS: CCA organoids established from different patients showed diverse morphology in contrast to monolayer structures of non-tumor organoids, and had the ability to form subcutaneous tumors in immunodeficient mice. CCA organoids demonstrated remarkably high photodynamic activity based on higher accumulation of protoporphyrin IX as a metabolite of 5-ALA compared to non-tumor organoids (40-71% vs. < 4%, respectively). Importantly, cancer cell-specific high photodynamic activity distinguished the organoids originated from biliary stenotic lesions from those of non-stenotic lesions in a CCA patient. The high photodynamic activity did not depend on the expression profile of heme biosynthesis genes. CONCLUSIONS: Distinct 5-ALA-based photodynamic activity could have diagnostic potential for the discrimination of CCA from non-tumor tissues.

The PDK1-FoxO1 signaling in adipocytes controls systemic insulin sensitivity through the 5-lipoxygenase-leukotriene B4 axis.

Although adipocytes are major targets of insulin, the influence of impaired insulin action in adipocytes on metabolic homeostasis remains unclear. We here show that adipocyte-specific PDK1 (3'-phosphoinositide-dependent kinase 1)-deficient (A-PDK1KO) mice manifest impaired metabolic actions of insulin in adipose tissue and reduction of adipose tissue mass. A-PDK1KO mice developed insulin resistance, glucose intolerance, and hepatic steatosis, and this phenotype was suppressed by additional ablation of FoxO1 specifically in adipocytes (A-PDK1/FoxO1KO mice) without an effect on adipose tissue mass. Neither circulating levels of adiponectin and leptin nor inflammatory markers in adipose tissue differed between A-PDK1KO and A-PDK1/FoxO1KO mice. Lipidomics and microarray analyses revealed that leukotriene B4 (LTB4) levels in plasma and in adipose tissue as well as the expression of 5-lipoxygenase (5-LO) in adipose tissue were increased and restored in A-PDK1KO mice and A-PDK1/FoxO1KO mice, respectively. Genetic deletion of the LTB4 receptor BLT1 as well as pharmacological intervention to 5-LO or BLT1 ameliorated insulin resistance in A-PDK1KO mice. Furthermore, insulin was found to inhibit LTB4 production through down-regulation of 5-LO expression via the PDK1-FoxO1 pathway in isolated adipocytes. Our results indicate that insulin signaling in adipocytes negatively regulates the production of LTB4 via the PDK1-FoxO1 pathway and thereby maintains systemic insulin sensitivity.

GCN2 regulates pancreatic ß cell mass by sensing intracellular amino acid levels.

EIF2AK4, which encodes the amino acid deficiency-sensing protein GCN2, has been implicated as a susceptibility gene for type 2 diabetes in the Japanese population. However, the mechanism by which GCN2 affects glucose homeostasis is unclear. Here, we show that insulin secretion is reduced in individuals harboring the risk allele of EIF2AK4 and that maintenance of GCN2-deficient mice on a high-fat diet results in a loss of pancreatic ß cell mass. Our data suggest that GCN2 senses amino acid deficiency in ß cells and limits signaling by mechanistic target of rapamycin complex 1 to prevent ß cell failure during the consumption of a high-fat diet.

Combined effect of diabetic retinopathy and diabetic kidney disease on all-cause, cancer, vascular and non-cancer non-vascular mortality in patients with type 2 diabetes: A real-world longitudinal study.

AIMS/INTRODUCTION: We assessed the relationship between diabetic retinopathy (DR) and/or diabetic kidney disease (DKD) according to their severity and all-cause, cancer, vascular and non-cancer non-vascular mortality in real-world patients with type 2 diabetes. MATERIALS AND METHODS: A total of 1,902 patients with type 2 diabetes were enrolled from 1995 to 1999 and followed to 2017. At baseline, DR was diagnosed in 374 patients, DKD in 529, vision-threatening DR in 123 and advanced DKD in 287. Patients were classified by the status of DR and DKD. Multivariate Cox regression analysis was carried out. RESULTS: There were 266 deaths during a median follow-up period of 18.6 years. Among these, 92 were from cancer, 78 were from vascular causes and 82 were from non-cancer non-vascular causes. DR and/or DKD predicted all-cause, vascular and non-cancer non-vascular mortality, but not cancer mortality. Similarly, vision-threatening DR and/or advanced DKD predicted all-cause, vascular and non-cancer non-vascular mortality, but not cancer mortality. Hazard ratios for all-cause, vascular and non-cancer non-vascular mortality were highest in the DR(+)DKD(+) group, and higher in the DR(-)DKD(+) and the DR(+)DKD(-) groups than in the DR(-)DKD(-) group. The results for vision-threatening DR and advanced DKD were similar. The interaction for non-cancer non-vascular mortality, but not all-cause and vascular mortality, between DR and DKD and between vision-threatening DR and advanced DKD might be significant. CONCLUSIONS: DR and DKD may be jointly and independently associated with all-cause, vascular and non-cancer non-vascular mortality, but not cancer mortality, according to their severity in real-world patients with type 2 diabetes.

Podocyte-specific deletion of tubular sclerosis complex 2 promotes focal segmental glomerulosclerosis and progressive renal failure.

Obesity can initiate and accelerate the progression of kidney diseases. However, it remains unclear how obesity affects renal dysfunction. Here, we show that a newly generated podocyte-specific tubular sclerosis complex 2 (Tsc2) knockout mouse model (Tsc2Δpodocyte) develops proteinuria and dies due to end-stage renal dysfunction by 10 weeks of age. Tsc2Δpodocyte mice exhibit an increased glomerular size and focal segmental glomerulosclerosis, including podocyte foot process effacement, mesangial sclerosis and proteinaceous casts. Podocytes isolated from Tsc2Δpodocyte mice show nuclear factor, erythroid derived 2, like 2-mediated increased oxidative stress response on microarray analysis and their autophagic activity is lowered through the mammalian target of rapamycin (mTOR)-unc-51-like kinase 1 pathway. Rapamycin attenuated podocyte dysfunction and extends survival in Tsc2Δpodocyte mice. Additionally, mTOR complex 1 (mTORC1) activity is increased in podocytes of renal biopsy specimens obtained from obese patients with chronic kidney disease. Our work shows that mTORC1 hyperactivation in podocytes leads to severe renal dysfunction and that inhibition of mTORC1 activity in podocytes could be a key therapeutic target for obesity-related kidney diseases.