Yoko Shimoda

Effect of dapagliflozin on colon cancer cell [Rapid Communication]

Dapagliflozin is a SGLT2 (Sodium/Glucose cotransporter 2) inhibitor that reduces circulating glucose levels in type 2 diabetic patients by blocking the SGLT2-dependent reabsorption of glucose in the kidney. Dapagliflozin is metabolized by UGT1A9 (UDP Glucuronosyltransferase 1 family, Polypeptidase A9), suppressing its SGLT2 inhibitor activity. However little information is available on whether dapagliflozin acts in the absence of dapagliflozin metabolism. Treatment with 0.5μM dapagliflozin significantly reduced the number of HCT116 cells, which express SGLT2 but not UGT1A9. This was independent of SGLT2 inhibition, as the SGLT2 inhibitor phlorizin had no effect. Dapagliflozin also enhanced Erk phosphorylation but without changing levels of uncleaved and cleaved PPAR and uncleaved caspase-3, suggesting that the cause of the decrease in HCT116 cell number was apoptosis independent cell death. Taken together, these data indicate a new potential role for dapagliflozin as an anticancer reagent in tumor cell populations that do not express UGT1A9.

Tctex1d2 Is a Negative Regulator of GLUT4 Translocation and Glucose Uptake

Tctex1d2 (Tctex1 domain containing 2) is an open reading frame that encodes for a functionally unknown protein that contains a Tctex1 domain found in dynein light chain family members. Examination of gene expression during adipogenesis demonstrated a marked increase in Tctex1d2 protein expression that was essentially undetectable in preadipocytes and markedly induced during 3T3-L1 adipocyte differentiation. Tctex1d2 overexpression significantly inhibited insulin-stimulated glucose transporter 4 (GLUT4) translocation and 2-deoxyglucose uptake. In contrast, Tctex1d2 knockdown significantly increased insulin-stimulated GLUT4 translocation and 2-deoxyglucose uptake. However, acute insulin stimulation (up to 30 min) in 3T3-L1 adipocytes with overexpression or knockdown of Tctex1d2 had no effect on Akt phosphorylation, a critical signal transduction target required for GLUT4 translocation. Although overexpression of Tctex1d2 had no significant effect on GLUT4 internalization, Tctex1d2 was found to associate with syntaxin 4 in an insulin-dependent manner and inhibit Doc2b binding to syntaxin 4. In addition, glucose-dependent insulinotropic polypeptide rescued the Tctex1d2 inhibition of insulin-stimulated GLUT4 translocation by suppressing the Tctex1d2-syntaxin 4 interaction and increasing Doc2b-Synatxin4 interactions. Taking these results together, we hypothesized that Tctex1d2 is a novel syntaxin 4 binding protein that functions as a negative regulator of GLUT4 plasma membrane translocation through inhibition of the Doc2b-syntaxin 4 interaction.

Effect of carbohydrate counting using bolus calculators on glycemic control in type 1 diabetes patients during continuous subcutaneous insulin infusion

The present study examined the long‐term efficacy of insulin pump therapy for type 1 diabetes patients when carried out using carbohydrate counting with bolus calculators for 1 year. A total of 22 type 1 diabetes patients who had just started continuous subcutaneous insulin infusion were examined and divided into two groups: one that was educated about carbohydrate counting using bolus calculators (n = 14); and another that did not use bolus calculators (n = 8). After 1 year, the hemoglobin A1c levels of the patient group that used bolus calculators decreased persistently and significantly (P = 0.0297), whereas those of the other group did not. The bodyweight, total daily dose of insulin and bolus percentage of both groups did not change. Carbohydrate counting using bolus calculators is necessary to achieve optimal and persistent glycemic control in patients undergoing continuous subcutaneous insulin infusion.

Assessment of factors determining an HbA1c concentration ≤ 7.5% in patients with type 1 diabetes

Establishing an optimal insulin regimen is crucial for maintaining glycemic control in patients with type 1 diabetes (T1D). The aim of the present study was to determine the insulin dose required to achieve an HbA1c concentration ≤7.5% in Japanese patients with T1D.

APPL1 promotes glucose uptake in response to mechanical stretch via the PKCζ-non-muscle myosin IIa pathway in C2C12 myotubes.

Expression of adaptor protein, phosphotyrosine interaction, pleckstrin homology domain, and leucine zipper containing 1 (APPL1) promoted glucose transporter 4 (GLUT4) translocation and glucose uptake in adipose and muscle tissues in response to stimulation with insulin, adiponectin, or exercise. In response to mechanical stretch, knockdown of APPL1 in C2C12 myotubes suppressed glucose uptake. APPL1-induced increased glucose uptake was mediated by protein kinase C (PKC) ζ but not AKT, AMPK, or calmodulin-dependent protein kinase. In myotubes overexpressing APPL1, PKCζ was phosphorylated and translocated to the plasma membrane (PM) in response to mechanical stretch. Phosphorylated PKCζ co-immunoprecipitated with protein phosphatase 2A (PP2A) under basal conditions, but dissociated upon myotube stretching. Moreover, stretch-induced phosphorylated PKCζ co-immunoprecipitated with non-muscle myosin IIa. Blebbistatin, an inhibitor of myosin II ATPase activity, suppressed APPL1-mediated stretch-induced glucose uptake and PKCζ translocation. Taken together these data demonstrate that in response to mechanical stretch, APPL1 enhances glucose uptake by modulating the activation and localization of PKCζ, as well as its functional interaction with both PP2A and myosin IIa. These findings support a new function for non-muscle myosin IIa in differentiated myotubes.

Glycosuria medicated with ipragliflozin and nifedipine or ipragliflozin and candesartan: a case report

IntroductionAnimal studies have reported that treatment with angiotensin II receptor blockers reduced kidney sodium-dependent glucose cotransporter expression. We therefore hypothesized that patients with hypertension treated with an angiotensin II receptor blocker (candesartan) would probably have an increased response to sodium-dependent glucose cotransporter inhibitor therapy (ipragliflozin) compared with patients treated with alternative hypertensive medications such as calcium channel blockers (nifedipine).Although sodium-dependent glucose cotransporter inhibitor (ipragliflozin) is a new anti-diabetic medicine, the clinical efficacy in the Japanese population has not been fully evaluated. We compared the combined effect of angiotensin II receptor blocker candesartan plus ipragliflozin with nifedipine plus ipragliflozin therapy and found that the combination of candesartan plus ipragliflozin was more effective in increasing glycosuria and lowering plasma glucose.Case presentationA 57-year-old Japanese man with essential hypertension was treated with candesartan. Candesartan was switched to nifedipine for the initial 10 days of an observation period and 5 days later he was started on ipragliflozin (day 6 of nifedipine treatment) with nifedipine for the next 5 days. Thereafter (from day 11 to day 20), candesartan was started instead of nifedipine and ipragliflozin was continued. In the last 5 days ipragliflozin was stopped and he was treated with candesartan alone. Neither nifedipine alone (0.038+/-0.004) nor candesartan alone (0.048+/-0.006) produce any trace amount of glycosuria. However, the extent of glycosuria under ipragliflozin with candesartan treatment (37.5+/-8.45) was significantly greater than that of ipragliflozin with nifedipine (23.75+/-0.35; P<0.05).ConclusionCandesartan demonstrated additive actions with ipragliflozin to increase glycosuria compared to ipragliflozin with nifedipine treatment.

HBA1C AND MEAN GLUCOSE DERIVED FROM SHORT-TERM CONTINUOUS GLUCOSE MONITORING ASSESSMENT DO NOT CORRELATE IN PATIENTS WITH HBA1C >8.

OBJECTIVE Optimum therapy for patients with diabetes depends on both acute and long-term changes in plasma glucose, generally assessed by glycated hemoglobin (HbA1c) levels. However, the correlation between HbA1c and circulating glucose has not been fully determined. Therefore, we carefully examined this correlation when glucose levels were assessed by continuous glucose monitoring (CGM). METHODS Fifty-one patients (70% female, 30% male) were examined; among them were 28 with type 1 diabetes and 23 with type 2 diabetes. Clinically determined HbA1c levels were compared with blood glucose determined by CGM during a short time period. RESULTS Changes in HbA1c levels up to 8.0% showed a clear and statistically strong correlation (R = 0.6713; P<.0001) with mean blood glucose levels measured by CGM, similar to that observed in the A1c-derived Average Glucose study in which patients were monitored for a longer period. However, we found no statistical correlation (R = 0.0498; P = .83) between HbA1c and CGM-assessed glucose levels in our patient population when HbA1c was >8.0%. CONCLUSION Short-term CGM appears to be a good clinical indicator of long-term glucose control (HbA1c levels); however, cautions should be taken while interpreting CGM data from patients with HbA1c levels >8.0%. Over- or underestimation of the actual mean glucose from CGM data could potentially increase the risks of inappropriate treatment. As such, our results indicate that a more accurate analysis of CGM data might be useful to adequately tailor clinical treatments. ABBREVIATIONS ADAG = A1c-Derived Average Glucose CGM = continuous glucose monitoring %CV = percent coefficient of variation HbA1c = glycated hemoglobin.

Maturity onset diabetes of the young 5 accompanied by duodenal cysts

Although inactivation of either the hepatocyte nuclear factor 1 (HNF1) homeobox A (Hnf1α) or HNF1 homeobox B (Hnf1β) genes in mice does not lead to any major intestinal dysfunction, double-mutant mice had a defect in intestinal water absorption. However, little is known about the effects of Hnf1β mutations on the intestine beyond their association with diabetes mellitus in humans. In the present study, we performed occasional esophagogastroduodenoscopies (EGDs) on a patient with maturity onset diabetes of the young (MODY) 5, and discovered the presence of duodenal cysts that gradually increased in number over 7 years of observation.

Subcutaneous abdominal adipose tissue is associated with an index of insulin sensitivity/resistance

ABSTRACT To assess whether there is any clinical significance for determining the normal range of subcutaneous abdominal fat area, we compared fat area with insulin sensitivity. Visceral and subcutaneous abdominal fat area the L4-L5 thoracic level was determined by computed tomography (CT). Plasma glucose and insulin levels were determined after an overnight fast and calculated by the homeostatic model assessment of insulin resistance (HOMA-IR). We analyzed 350 (180 male and 170 female) subjects whose BMI was 18.5≤BMI<25. The subcutaneous abdominal fat area of the female subjects was 124.7 ± 46.13 cm2 and that of male subjects was 77.53 ± 37.53 cm2 (mean ± SD). We compared HOMA-IR between subjects whose visceral abdominal fat area was above 100 cm2 and subcutaneous abdominal fat area below the mean + 2SD (15 subjects, 6 male and 9 female) with subjects whose visceral abdominal fat area was also above 100 cm2 but whose subcutaneous abdominal fat area was above the mean + 2SD (20 subjects, 7 male and 13 female). The HOMA-IR of the former subjects group was 8.17+/−6.22 and that of the latter subjects group was 3.37+/−2.07 (p = 0.0486). Subjects with increased subcutaneous abdominal fat area displayed lower HOMA-IR values, demonstrating a protective effect of subcutaneous fat for individuals with visceral fat area above 1002 cm.

Paget's disease of bone resembling bone metastasis from gastric cancer.

A 74-year-old man had an endoscopic type 0′-IIc tumor in the upper gastric body on the greater curvature and biopsy showed the tumor to be a well-differentiated adenocarcinoma (Group 5). He was referred to us for endoscopic submucosal dissection (ESD). Endoscopy revealed fold convergency, fold swelling, and fusion of the fold, indicating tumor invasion into the submucosa, which was outside the indications for ESD. In addition, there was an increase of serum bone-type alkaline phosphatase (ALP-III and ALP-IV) and urinary cross-linked N-terminal telopeptide of type I collagen (a bone metabolism marker), while 18F-fluorodeoxyglucose positron emission tomography showed increased uptake in the left pelvis and Th10, suggesting bone metastases. We first diagnosed gastric cancer with bone metastases; however, the symptoms suggested pathological bone fracture and no bone pain. Therefore, a computed tomography-guided aspiration bone biopsy was performed to exclude the possibility of Paget’s disease of bone. Biopsy specimens revealed no tumor and a mosaic pattern. No increased uptake of 18F-FAMT (L-[3-18F] α-methyltyrosine) supported a diagnosis of no bone metastases from gastric cancer. We finally diagnosed gastric cancer accompanied by Paget’s disease of bone and performed a laparoscopy-assisted proximal gastrectomy. The pathological diagnosis was U less 0-IIb, and U post 0-IIc ypT1a (M) N0H0P0M0 yp stage IA. In gastric cancer patients with suspected bone metastasis, we also need to consider Paget’s disease of bone.