Ken-ichi Nemoto

Transient suppression of PPARγ directed ES cells into an osteoblastic lineage

Osteoblasts and adipocytes are believed to share a common progenitor. Peroxisome proliferator‐activated receptor γ (PPARγ) plays a key role in the switching of these two cell lineages. Here, we demonstrated the differentiation of ES cells into an osteoblastic lineage using siRNA against PPARγ without the addition of any osteogenic factors. We found that PPARγ‐siRNA downregulated the expression of aP2 mRNA and lipid accumulation, whereas it upregulated the expression of osteocalcin and calcium deposition. These results suggested that ES cells were directed into an osteoblastic lineage. Therefore, transient suppression using PPARγ‐siRNA may be a novel tool to induce differentiation of ES cells into osteoblasts.

4-Hydroxy hexenal derived from dietary n-3 polyunsaturated fatty acids induces anti-oxidative enzyme heme oxygenase-1 in multiple organs.

It has recently been reported that expression of heme oxygenase-1 (HO-1) plays a protective role against many diseases. Furthermore, n-3 polyunsaturated fatty acids (PUFAs) were shown to induce HO-1 expression in several cells in vitro, and in a few cases also in vivo. However, very few reports have demonstrated that n-3 PUFAs induce HO-1 in vivo. In this study, we examined the effect of fish-oil dietary supplementation on the distribution of fatty acids and their peroxidative metabolites and on the expression of HO-1 in multiple tissues (liver, kidney, heart, lung, spleen, intestine, skeletal muscle, white adipose, brown adipose, brain, aorta, and plasma) of C57BL/6 mice. Mice were divided into 4 groups, and fed a control, safflower-oil, and fish-oil diet for 3 weeks. One group was fed a fish-oil diet for just 1 week. The concentration of fatty acids, 4-hydroxy hexenal (4-HHE), and 4-hydroxy nonenal (4-HNE), and the expression of HO-1 mRNA were measured in the same tissues. We found that the concentration of 4-HHE (a product of n-3 PUFAs peroxidation) and expression of HO-1 mRNA were significantly increased after fish-oil treatment in most tissues. In addition, these increases were paralleled by an increase in the level of docosahexaenoic acid (DHA) but not eicosapentaenoic acid (EPA) in each tissue. These results are consistent with our previous results showing that DHA induces HO-1 expression through 4-HHE in vascular endothelial cells. In conclusion, we hypothesize that the HO-1-mediated protective effect of the fish oil diet may be through production of 4-HHE from DHA but not EPA in various tissues.

Predictors for Mild and Severe Hypoglycemia in Insulin-Treated Japanese Diabetic Patients

The objective of this study was to explore predictors, including social factors, lifestyle factors, and factors relevant to glycemic control and treatment, for mild and severe hypoglycemia in insulin-treated Japanese diabetic patients. This study included 123 insulin-treated diabetic patients who were referred to the diabetes clinic between January and July 2013 at Shiga University of Medical Science Hospital. After a survey examining the various factors, patients were followed for 6 months. During the follow-up period, blood glucose was self-monitored. Mild hypoglycemia was defined as blood glucose level 50–69 mg/dl, and severe hypoglycemia was defined as blood glucose level ≤49 mg/dl. Multinomial logistic regression was used to estimate the adjusted odds ratio (OR) and 95% confidence interval (CI) of each factor for mild and severe hypoglycemia. During the 6-month follow-up period, 41 (33.3%) patients experienced mild hypoglycemia, and 20 (16.3%) experienced severe hypoglycemia. In multivariable-adjusted analyses, assistance from family members at the time of the insulin injection [presence/absence, OR (95% CI): 0.39 (0.16–0.97)] and drinking [current drinker/non- and ex-drinker, OR (95% CI): 4.89 (1.68–14.25)] affected mild hypoglycemia. Assistance from family members at the time of insulin injection [presence/absence, OR (95% CI): 0.19 (0.05–0.75)] and intensive insulin therapy [yes/no, OR (95% CI): 3.61 (1.06–12.26)] affected severe hypoglycemia. In conclusion, our findings suggest that not only a factor relevant to glycemic control and treatment (intensive insulin therapy) but also a social factor (assistance from family members) and a lifestyle factor (current drinking) were predictors for mild or severe hypoglycemia in Japanese insulin-treated diabetic patients.

A case of local delayed-type allergy to zinc-containing insulin as a cause of diabetic ketoacidosis in a patient with type 1 diabetes mellitus undergoing continuous subcutaneous insulin infusion

We herein report a case involving a woman with type 1 diabetes and a history of metal allergy who developed a local delayed-type (type IV) allergy to zinc-containing insulin. She had been treated by continuous subcutaneous insulin infusion, but her glycemic control was poor, and she developed diabetic ketoacidosis. Her plasma insulin concentration was unexpectedly low during use of insulin lispro, but it was recovered by changing from the zinc-containing insulin lispro to the zinc-free insulin glulisine. Intradermal tests showed no reactions to various insulins except for zinc chloride. A skin biopsy at the injection site of insulin lispro showed invasion of lymphocytes, neutrophils, and eosinophils, but a skin biopsy at the injection site of insulin glulisine showed invasion of only lymphocytes. A drug lymphocyte stimulation test against polaprezinc, an antiulcer drug containing zinc, was positive. Therefore, we diagnosed the patient with local delayed allergy to zinc-containing insulin. Insulin allergy should be considered as a possible cause of poor glycemic control and diabetic ketoacidosis in patients with type 1 diabetes.