BackgroundWe developed a simple and new insulin resistance index derived from a glucose clamp and a meal tolerance test (MTT) in Japanese patients with type 2 diabetes mellitus.MethodsFifteen patients [mean age: 53 years, fasting plasma glucose (FPG) 7.7 mmol/L, HbA1c 7.1% (54 mmol/mol), body mass index 26.8 kg/m2] underwent a MTT and a glucose clamp. Participants were given a test meal (450 kcal). Plasma glucose and insulin were measured at 0 (fasting), 30, 60, 120, and 180 min. Serum C-peptide immunoreactivity (CPR) was measured at 0 (fasting; F-CPR) and 120 min. Homeostasis model assessment of insulin resistance (HOMA-IR) and insulin sensitivity indices (ISI) were calculated from the MTT results. The glucose infusion rate (GIR) was measured during hyperinsulinemic–euglycemic glucose clamps.ResultsThe mean GIR in all patients was 5.8 mg·kg–1·min–1. The index 20/(F-CPR × FPG) was correlated strongly with GIR (r = 0.83, P < 0.0005). HOMA-IR (r = −0.74, P < 0.005) and ISI (r = 0.66, P < 0.01) were also correlated with GIR. In 10 patients with mild insulin resistance (GIR 5.0–10.0 mg·kg–1·min–1), 20/(F-CPR × FPG) was very strongly correlated with GIR (r = 0.90, P < 0.0005), but not with HOMA-IR and ISI (r = −0.49, P = 0.15; r = 0.20, P = 0.56, respectively). In patients with mild insulin resistance, plasma adiponectin (r = 0.65, P < 0.05), but not BMI or waist circumstance, was correlated with GIR.Conclusions20/(F-CPR × FPG) is a simple and effective index of insulin resistance, and performs better than HOMA-IR and ISI in Japanese patients with type 2 diabetes mellitus. Our results suggest that 20/(F-CPR × FPG) is a more effective index than HOMA-IR in Japanese patients with mild insulin resistance.

PA28-gamma is the activator of 20S proteasome, the ATP-dependent proteolytic system that plays an important role in cell cycle progression in various cell types. In this paper, we show the abnormally high expression of PA28-gamma in various thyroid neoplasms. Thyroid samples were obtained from patients with normal thyroid (4 cases) and with the following diseases: papillary adenocarcinoma (13 cases), multinodular goiter (4 cases), and anaplastic carcinoma (1 case). PA28-gamma expression was estimated by immunohistochemical staining and Western blotting. In all of the papillary adenocarcinoma samples, PA28-gamma was abnormally overexpressed, especially in cancer cells existing at the peripheral region of the cancer mass or in cancer cells invading the capsular region surrounding the cancer mass. In cancer cells of these areas, PA28-gamma was predominantly distributed in nucleus rather than in the cytoplasm of cancer cells. On the other hand, no obvious PA28-gamma expression was observed in the adjacent normal thyroid follicular cells. In multinodular goiter, the expression of PA28-gamma was relatively low compared with papillary adenocarcinoma. In anaplastic carcinoma, PA28-gamma was expressed at the highest level, especially in poorly differentiated regions such as squamous metaplasia of anaplastic cancer tissue. Therefore, the PA28-gamma expression seems to be restricted to thyroid cancer cells, especially in the region where the growth rate of cancer cells is accelerated. This result is further confirmed by the fact that C2, alpha-subunit of 20S proteasome, and proliferating cell nuclear antigen are similarly overexpressed in this region. Thus, PA28-gamma might be involved in the regulatory system for the cell cycle. Moreover, the growth of thyroid cancer cell lines was affected by the proteasome inhibitor, clasto-lactacystin beta-lactone. These results demonstrate that PA28-gamma is overexpressed in thyroid cancer, especially in its growth-accelerated cells.

BackgroundGalectin-3 is a family of soluble beta-galactoside-binding lectins that play many important regulatory roles in inflammation. Galectin-3-deficient mice have been shown to exhibit excess adiposity, hyperglycemia, insulin resistance and systemic inflammation. We investigated the association between serum galectin-3 and insulin resistance in patients with type 2 diabetes using a glucose clamp method.MethodsThis was a cross-sectional study. Twenty patients (mean fasting plasma glucose 7.6 mmol/L, HbA1c 7.2%, BMI 28.1 kg/m2) underwent a meal tolerance test and glucose clamp test. Participants were given a test meal and plasma glucose and insulin were measured at 0, 30, 60, 120 and 180 min. The glucose disposal rate was measured during hyperinsulinemic-euglycemic glucose clamps. Serum galectin-3 levels were measured using the enzyme-linked immunosorbent assay method.ResultsThe mean serum galectin-3 level was 5103 pg/ml. Galectin-3 levels correlated significantly with the glucose disposal rate (R = 0.71, P < 0.001), fasting insulin (R = −0.56, P < 0.01), homeostasis model assessment for insulin resistance (R = −0.52, P < 0.05), and the insulin sensitivity index (R = 0.62, P < 0.005). Galectin-3 levels also positively correlated with the serum adiponectin level (R = 0.61, P < 0.05), but not with the high-sensitive C-reactive protein and interleukin-6 and −10.ConclusionsThese results suggest that low levels of serum galectin-3 are associated with insulin resistance in patients with type 2 diabetes.

Sodium-glucose cotransporter 2 (SGLT2) inhibition induces glucosuria and decreases blood glucose levels in diabetic patients and lowers hypoglycemic risk. SGLT1 is expressed in the kidney and intestine; SGLT1 inhibition causes abdominal symptoms such as diarrhea and reduces incretin secretion. Therefore, SGLT2 selectivity is important. Ipragliflozin is highly selective for SGLT2. In type 2 diabetes mellitus (T2DM), urinary glucose excretion increased to 90 g/24 h after 28 d of treatment with ipragliflozin 300 mg/d. Twelve weeks of ipragliflozin 50 mg/d vs placebo reduced glycated hemoglobin and body weight by 0.65% and 0.66 kg, respectively, in Western T2DM patients, and by 1.3% and 1.89 kg, respectively, in Japanese patients. Ipragliflozin (highly selective SGLT2 inhibitor) improves glycemic control and reduces body weight and lowers hypoglycemic risk and abdominal symptoms. Ipragliflozin can be a novel anti-diabetic and anti-obesity agent.

The study identifies pendrin as a novel autoantigen recognized by patients with autoimmune thyroid diseases and proposes the use of pendrin antibodies as an accurate diagnostic tool.