Characteristics of the glycometabolic categories based on the oral glucose tolerance test results in Japanese adults without diabetes.

OBJECTIVE: We aimed to classify Japanese adults without diabetes into different categories based on the oral glucose tolerance test (OGTT) and characterize their insulin sensitivity and insulin secretion. PATIENTS AND METHODS: The OGTT was performed on 1,085 Japanese individuals without diabetes (aged 20-64 years); blood glucose and insulin levels were measured at 0, 30-, 60-, 90-, and 120-min. Fasting blood chemistry, hematology, and urine were analyzed. The participants were classified into four categories based on the following: (A) 30 min post-load plasma glucose levels < 157 mg/dL and/or (B) 120 min post-load plasma glucose levels < 126 mg/dL and Matsuda index > 4.97. Category 1 satisfied both conditions, category 2 satisfied condition A but not B, category 3 satisfied condition B but not A, and category 4 satisfied neither condition. RESULTS: Overall, 46%, 21%, 13%, and 20% of the participants were classified into categories 1, 2, 3, and 4, respectively. Compared with category 1, the characteristics of the other categories were: 2, low insulin sensitivity and high blood glucose levels during the later period; 3, low insulin secretion and a rapid increase in blood glucose levels; and 4, combined characteristics of categories 2 and 3. Most blood test values besides glucose metabolism in category 4 were also worse than those in category 1. Categories 1 and 2 had a high proportion of females, whereas categories 3 and 4 had a low proportion. CONCLUSIONS: Japanese adults without diabetes are classified into four categories with different insulin sensitivities and insulin secretion using OGTT results. Each category has different characteristics of age and sex distribution and clinical values besides glucose metabolism.

Hop-derived prenylflavonoid isoxanthohumol suppresses insulin resistance by changing the intestinal microbiota and suppressing chronic inflammation in high fat diet-fed mice.

OBJECTIVE: To assess whether the hop-derived polyphenol isoxanthohumol suppresses insulin resistance by changing the intestinal microbiota. MATERIALS AND METHODS: Male C57BL/6J mice (7 weeks of age) were divided into five groups (n = 9-10): Normal Diet (ND), High Fat Diet (HFD), HFD + low dose isoxanthohumol (0.01%IX), HFD + medium dose isoxanthohumol (0.03% IX), and HFD + high dose isoxanthohumol (0.1% IX). Oral glucose tolerance tests (OGTTs) were performed at 4 and 8 weeks, and insulin tolerance tests (ITTs) were performed at 13 weeks. 16S rRNA gene sequencing analyses revealed the fecal microbiota profiles, and the relative abundance of Akkermansia muciniphila and Clostridium cluster XI was calculated by qRT-PCR. Plasma lipopolysaccharide (LPS) levels were measured by ELISA, and mRNA expression levels of tumor necrosis factor (TNF)-α, and interleukin (IL)-1ß in epididymal adipose tissues were measured by qRT-PCR. RESULTS: Isoxanthohumol showed antibacterial activity towards several bacterial species and mitigated impaired glucose tolerance and insulin resistance induced by the HFD in a dose-dependent manner, as shown by OGTTs and ITTs. The concentration of phylum Verrucomicrobia bacteria dramatically increased in the 0.1% IX group, the relative abundance of A. muciniphila increased, and that of Clostridium cluster XI decreased. Moreover, the intake of isoxanthohumol decreased the levels of plasma LPS and mRNA expression of TNF-α and IL-1ß in epididymal adipose tissues. CONCLUSIONS: We found that isoxanthohumol can suppress HFD-induced insulin resistance by changing the intestinal microbiota and reducing the expression of inflammation factors.