Lipase-catalyzed preparation of phospholipids containing n-3 polyunsaturated fatty acids from soy phospholipids

To utilize n-3 polyunsaturated fatty acid (PUFA) for a wide range of applications, we prepared phospholipids (PLs) containing PUFAs as constituent fatty acids (PUFA-PLs) via commercially available lipase OF-mediated transacylation with PL from soy (Soy-PL) and ethyl ester of PUFA (PUFA-Et). In a preliminary study to evaluate PUFA-incorporation (wt%) on phosphatidylcholine (PC), we observed that dehydration of Soy-PL is critical. PUFA-incorporation in PLs increased with acyl ratio and time. Finally, maximum PUFA-incorporation (47.1 ± 2.1 wt%) was obtained using the following reaction conditions: 2.0 mmol of Soy-PL, a PUFA-Et/Soy-PL acyl ratio of 7, 13 mL of hexane, 2.2 × 10(5) U of lipase OF, 500 rpm of agitation, a temperature of 37°C, and 72 h of reaction time. The analysis of fatty acid composition at the sn-2 position of obtained PL revealed that PUFAs incorporated into Soy-PL localized to the sn-2 position of the PL molecule in spite of using lipase OF whose positional specificity is random for triacylglycerol.

Association of living alone with the presence of undiagnosed diabetes in Japanese men: the role of modifiable risk factors for diabetes: Toranomon Hospital Health Management Center Study 13 (TOPICS 13)

AIMS

To investigate whether living alone was associated with the presence of undiagnosed diabetes and whether this association could be attenuated by modifiable lifestyle habits.

METHODS

This cross-sectional study included 6400 Japanese men without a history of diagnosed diabetes. Individuals with currently undiagnosed diabetes were identified through fasting glucose concentration ≥7.0 mmol/l or HbA1c concentration ≥ 48 mmol⁄mol (≥ 6.5%). Effect modification was examined using body mass index, hypertension, history of dyslipidaemia, drinking habits, smoking habits, physical activity, vegetable intake, emotional stress and depressed mood.

RESULTS

Men who lived alone (n = 1098) had a significantly elevated odds ratio for having undiagnosed diabetes in an age-adjusted model (odds ratio 1.45, 95% CI 1.07, 1.96; P = 0.018). After adjustment for lifestyle factors, the association was slightly attenuated (odds ratio 1.40, 95% CI 1.02, 1.91; P = 0.036). After further adjustment for all factors mentioned above, living alone was still marginally significantly associated with the presence of undiagnosed diabetes (odds ratio 1.38, 95% CI 1.003, 1.90; P = 0.048). A significant association of living alone with the presence of undetected diabetes was particularly observed among men who were overweight, currently smoked and were physically inactive, or had any one of those three factors.

CONCLUSIONS

The association between undiagnosed diabetes and living alone can be partially influenced by modifiable lifestyle factors. Men who lived alone, especially those who did not engage in favourable lifestyle habits, were more likely to have undiagnosed diabetes. Such individuals have a higher probability of having undetected diabetic hyperglycaemia and would need to undergo glucose tests to identify the disease.

Effect of experimental jaw muscle pain on EMG activity and bite force distribution at different level of clenching

Bite force at different levels of clenching and the corresponding electromyographic (EMG) activity in jaw-closing muscles were recorded in 16 healthy women before, during and after painful stimulation of the left masseter muscle. Experimental pain was induced by infusion of 5·8% hypertonic saline (HS), and 0·9% isotonic saline (IS) was infused as a control. EMG activity was recorded bilaterally from the masseter and temporalis muscles, and static bite force was assessed by pressure-sensitive films (Dental Pre-scale) at 5, 50 and 100% of maximal voluntary contraction (MVC) during each session. Visual feedback was applied by showing EMG activity to help the subject perform clenching at 5, 50 and 100% MVC, respectively. EMG activity at 100% MVC in left and right masseter decreased significantly during painful HS infusion (1·7-44·6%; P < 0·05). EMG activity at 5% and 50% MVC was decreased during HS infusion in the painful masseter muscle (4·8-18·6%; P < 0·05); however, EMG activity in the other muscles increased significantly (18·5-128·3%; P < 0·05). There was a significant increase in bite force in the molar regions at 50% MVC during HS infusion and in the post-infusion condition (P < 0·05). However, there were no significant differences in the distribution of forces at 100% MVC. In conclusion, experimental pain in the masseter muscle has an inhibitory effect on jaw muscle activity at maximal voluntary contraction, and compensatory mechanisms may influence the recruitment pattern at submaximal efforts.

Development of a new scoring system for predicting the 5 year incidence of type 2 diabetes in Japan: the Toranomon Hospital Health Management Center Study 6 (TOPICS 6)

AIMS/HYPOTHESIS

The aims of this study were to assess the clinical significance of introducing HbA(1c) into a risk score for diabetes and to develop a scoring system to predict the 5 year incidence of diabetes in Japanese individuals.

METHODS

The study included 7,654 non-diabetic individuals aged 40-75 years. Incident diabetes was defined as fasting plasma glucose (FPG) ≥7.0 mmol/l, HbA(1c) ≥6.5% (48 mmol/mol) or self-reported clinician-diagnosed diabetes. We constructed a risk score using non-laboratory assessments (NLA) and evaluated improvements in risk prediction by adding elevated FPG, elevated HbA(1c) or both to NLA.

RESULTS

The discriminative ability of the NLA score (age, sex, family history of diabetes, current smoking and BMI) was 0.708. The difference in discrimination between the NLA + FPG and NLA + HbA(1c) scores was non-significant (0.836 vs 0.837; p = 0.898). A risk score including family history of diabetes, smoking, obesity and both FPG and HbA(1c) had the highest discrimination (0.887, 95% CI 0.871, 0.903). At an optimal cut-off point, sensitivity and specificity were high at 83.7% and 79.0%, respectively. After initial screening using NLA scores, subsequent information on either FPG or HbA(1c) resulted in a net reclassification improvement of 42.7% or 52.3%, respectively (p < 0.0001). When both were available, net reclassification improvement and integrated discrimination improvement were further improved at 56.7% (95% CI 47.3%, 66.1%) and 10.9% (9.7%, 12.1%), respectively.

CONCLUSIONS/INTERPRETATION

Information on HbA(1c) or FPG levels after initial screening by NLA can precisely refine diabetes risk reclassification.

Drug sensitivity test for primary culture of human cancer-cells using collagen gel embedded culture and image-analysis

A new drug sensitivity assay method using the collagen gel embedded culture and image analysis was developed. Human cancer cells cultured in collagen gels showed extremely high cloning efficiency and in vivo-like drug response. In addition, image analysis was used successfully for the first time to automatically discriminate cancer colonies from contaminating fibroblastic cells by taking advantage of the difference in shape between them after cultivation to determine the drug response of cultured cancer cells accurately and easily. A new approach for the practical use of the drug sensitivity test on human cancer cells is suggested.

Genetic and environmental factors affecting peak bone mass in premenopausal Japanese women

The purpose of this study was to examine the relationships between peak bone mass and genetic and environmental factors. We measured whole-body bone mineral density (BMD), lumbar spine BMD, and radius BMD with dual-energy X-ray absorptiometry (DXA) and analyzed eight genetic factors: vitamin D receptor (VDR)-3', VDR-5', estrogen receptor (ER), calcitonin receptor (CTR), parathyroid hormone (PTH), osteocalcin (OC), apolipoprotein E (ApoE), and fatty acid binding protein 2 (FABP2) allelic polymorphisms using polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLPs). We also surveyed menstrual history, food intake, and history of physical activity using questionnaires.After adjusting for age, body mass index (BMI), current smoking status, current Ca intake, alcohol intake, menoxenia, and physical activity, the mean BMD in subjects with the HH/Hh genotype was significantly higher than that of subjects with the hh genotype for whole-body BMD (mean±SD, 1.20±0.10 vs. 1.18±0.09 g/cm(2); HH/Hh vs. hh, p=0.04) and at lumbar spine BMD (mean±SD, 1.18±0.14 vs. 1.14±0.12 g/cm(2); HH/Hh vs. hh, p=0.02) in OC allelic polymorphism. Furthermore, the results of multiple regression analyses taking the 8 genetic factors plus the 7 environmental factors listed above into account showed that the strongest factor contributing to BMD was BMI at any site (whole-body and lumbar BMD p<0.0001, radius BMD p=0.0029). In addition, OC polymorphism (p=0.0099), physical activity (p=0.0245), menoxenia (p=0.0384), and PTH polymorphism (p=0.0425) were independent determinants for whole-body BMD, and OC polymorphism (p=0.0137) and physical activity (p=0.0421) were independent determinants for lumbar BMD and radius BMD, respectively.

An in vitro chemosensitivity test for solid human tumors using collagen gel droplet embedded cultures

In vitro chemosensitivity testing using a collagen gel droplet embedded culture drug sensitivity test (CD-DST), was conducted with several types of solid cancer. The overall evaluable rate was 80% (443/554), including 76% for lung (n=243), 78% for breast (n=110), 87% for gastric (n=62), 83% for colorectal (n=107) cancers and 88% for 32 metastatic brain tumors. The in vitro sensitivity of breast, gastric and colorectal cancers to mitomycin C (MMC), cisplatin (CDDP), 5-fluorouracil (5-FU) and doxorubicin (DXR) was similar to the efficacy rates reported for each drug. This was also observed with lung cancer, the sensitivity of which to MMC, CDDP, vindesine (VDS) and etoposide (VP-16) was similar to the clinical efficacy. The clinical response to chemotherapy was compared with the results of in vitro chemosensitivity testing in Il patients: the clinical correlation was 91%, with a 80% true positive and 100% true negative rate. These results suggest that the CD-DST may be clinically useful by allowing the prediction of clinical response in various solid cancers.

High normal HbA(1c) levels were associated with impaired insulin secretion without escalating insulin resistance in Japanese individuals: the Toranomon Hospital Health Management Center Study 8 (TOPICS 8)

AIMS

We aimed to characterize the association of insulin resistance, impaired insulin secretion and β-cell dysfunction in relation to HbA(1c) levels in a non-diabetic range in Japanese individuals without clinically diagnosed diabetes.

METHODS

This cross-sectional study included 1444 individuals without a history of outpatient treatment of diabetes or use of insulin or oral hypoglycaemic agents. The homeostasis model assessment of insulin resistance and beta-cell function, insulinogenic index, Matsuda index and disposition index were calculated using data from 75-g oral glucose tolerance tests and compared across quintile (Q) categories of HbA(1c) levels.

RESULTS

Fasting plasma glucose and 30-min and 60-min plasma glucose (PG) levels were significantly higher when HbA(1c) exceeded 36 mmol/mol (5.4%). A HbA(1c) concentration of 36-37 mmol/mol (5.4-5.5%) (Q3) was significantly associated with a 15% lower homeostasis model assessment of β-cell function value and 31% lower insulinogenic index value compared with HbA(1c) ≤ 32 mmol/mol (≤ 5.1%) (Q1) (P <0.01). Further, a HbA(1c) concentration of 38-40 mmol/mol (5.6-5.8%) (Q4) was associated with 17% (P <0.01) and 24% (P <0.05) reductions in those indexes, respectively. However, the homeostasis model assessment of insulin resistance was not significantly elevated and the Matsuda index was not significantly lower unless HbA(1c) exceeded 41 mmol/mol (5.9%). Individuals with HbA(1c) ≥ 41 mmol/mol (≥ 5.9%) (Q5) had a 69% lower disposition index than those with a HbA(1c) concentration of ≤ 32 mmol/mol (≤ 5.1%) (Q1).

CONCLUSIONS

Elevated HbA(1c) levels ≥ 41 mmol/mol (≥ 5.9%) were associated with substantial reductions in insulin secretion, insulin sensitivity and β-cell dysfunction in Japanese individuals not treated for diabetes. High normal HbA(1c) levels of 36-40 mmol/mol (5.4-5.8%) were also associated with impaired insulin secretion without marked insulin resistance in Japanese individuals.

Screening for pre-diabetes to predict future diabetes using various cut-off points for HbA(1c) and impaired fasting glucose: the Toranomon Hospital Health Management Center Study 4 (TOPICS 4)

AIM

To evaluate various screening criteria for pre-diabetes to identify which combination of impaired fasting glucose and elevated HbA(1c) values performs most effectively in predicting future diabetes in a large cohort of Japanese individuals.

METHODS

The study included 4670 men and 1571 women without diabetes (diabetes: fasting plasma glucose ≥ 7.0 mmol/l, HbA(1c) ≥ 48 mmol/mol (≥ 6.5%), or self-reported clinician-diagnosed diabetes). Pre-diabetes was diagnosed by a combination of impaired fasting glucose (fasting plasma glucose 5.6-6.9 mmol/l or 6.1-6.9 mmol/l) and elevated HbA(1c) [39-46 mmol/mol (5.7-6.4%) or 42-46 mmol/mol (6.0-6.4%)].

RESULTS

During a 5-year follow-up, 338 incident cases of diabetes occurred. The combination of HbA(1c) 39-46 mmol/mol (5.7-6.4%) and fasting plasma glucose 5.6-6.9 mmol/l yielded the highest sensitivity (86%) and generated a large population-attributable per cent risk (78%) for predicting development of diabetes. Among individuals classified as having pre-diabetes by any of the four combined criteria, 20.5-32.0% reverted to the normoglycaemic state as having neither elevated HbA(1c) nor impaired fasting glucose at the last follow-up examination. At 5.6 years after the baseline examination, however, pre-diabetic individuals who fulfilled both HbA(1c) 42-46 mmol/mol (6.0-6.4%) and fasting plasma glucose 6.1-6.9 mmol/l had a 100% cumulative risk of developing diabetes.

CONCLUSIONS

The combination of HbA(1c) 39-46 mmol/mol (5.7-6.4%) and fasting plasma glucose 5.6-6.9 mmol/l would have the best performance in reducing the likelihood of missing future cases of diabetes. Identifying pre-diabetic individuals who strictly fulfil HbA(1c) 42-46 mmol/mol (6.0-6.4%) and fasting plasma glucose 6.1-6.9 mmol/l would predict definite progression to diabetes.

Microsomal prostaglandin E synthase-1 is involved in multiple steps of colon carcinogenesis

Accumulating evidence indicates that cyclooxygenase (COX)-2-derived prostaglandin (PG) E(2) is involved in the development of various tumors, including colorectal cancer. However, the precise contribution of microsomal PGE synthase (mPGES)-1, a terminal enzyme that acts downstream of COX-2 in the PGE(2)-biosynthetic pathway, to multiple processes of tumor development is not yet fully understood. Here, we show the pro-tumorigenic role of mPGES-1 in chemical carcinogen-induced colon carcinogenesis and intrasplenic tumor transplantation models. Genetic deletion of mPGES-1 significantly reduced both the total number and size of colorectal polyps at 18 weeks after azoxymethane administration with reduced nuclear translocation of β-catenin, altered expression profiles of chemokines/cytokines and increased production of antitumorigenic PGs, prostaglandin D(2) and prostacyclin in tumor tissues. At an early stage (6 weeks), mPGES-1 deficiency significantly reduced the number of aberrant crypt foci, while its transgenic overexpression increased the number. Furthermore, the growth of intrasplenically transplanted tumor cells was suppressed in mPGES-1 knockout (KO) mice. Co-culture of tumor cells with bone marrow-derived macrophages (BM-MΦs) isolated from wild-type (WT) mice resulted in the induction of mPGES-1 in BM-MΦs and increased the growth of tumor cells in vitro, whereas mPGES-1-null BM-MΦs failed to facilitate tumor growth. The adoptive transfer of WT BM-MΦs into mPGES-1 KO mice restored the growth of transplanted tumor cells, indicating that mPGES-1 in MΦs is important for the growth of adjacent tumor cells. Taken together, our findings suggest that the inhibition of mPGES-1 is an alternative therapeutic target for colorectal and possibly other cancers.

Low serum potassium levels and risk of type 2 diabetes: the Toranomon Hospital Health Management Center Study 1 (TOPICS 1)

AIMS/HYPOTHESIS

Evidence has suggested that low serum potassium concentrations decrease insulin secretion, leading to glucose intolerance, and that hypokalaemia induced by diuretics increases the risk for diabetes in hypertensive individuals. However, no prospective study has investigated the association between serum potassium and the development of type 2 diabetes in a healthy cohort comprised of Asian individuals not being administered antihypertensive medications. This study aimed to investigate whether low serum potassium is associated with increased risk of type 2 diabetes in apparently healthy Japanese men.

METHODS

We followed 4,409 Japanese men with no history of diabetes, use of antihypertensives, renal dysfunction or liver dysfunction (mean ± SD age, 48.4 ± 8.4 years). Cox proportional hazards regression was used to estimate HRs for incident diabetes (fasting plasma glucose level ≥ 7.0 mmol/l, HbA(1c) ≥ 6.5% or self-reported) including serum potassium concentration as either a categorical or a continuous variable.

RESULTS

During a 5 year follow-up, 250 individuals developed type 2 diabetes. The lowest tertile of serum potassium (2.8-3.9 mmol/l) was independently associated with the development of diabetes after adjustment for known predictors (HR 1.57 [95% CI, 1.15-2.15]) compared with the highest tertile (4.2-5.4 mmol/l). Every 0.5 mmol/l lower increment in the baseline serum potassium level was associated with a 45% (12-87%) increased risk of diabetes.

CONCLUSIONS/INTERPRETATION

Mild to moderately low serum potassium levels, within the normal range and without frank hypokalaemia, could be predictive of type 2 diabetes in apparently healthy Japanese men.

Enzymatic preparation of structured oils containing short-chain fatty acids

Structured oils prepared by enzymatic transacylation with triacylglycerols (TAGs) and various fatty acids (FAs) were characterized. Transacylation with trilaurin and saturated FAs (C4:0-C16:0) was performed using Lipozyme RM-IM under standard reaction conditions. The structured oils thus produced had transacylation ratios of 25-37%, as medium-chain FAs > long-chain FAs > short-chain FAs. This result confirmed that short-chain FAs have little reactivity in enzymatic transacylation. All prepared oils shared the same composition of TAG molecular species, as demonstrated by HPLC analysis, and contained a mixture of mono-substituted, di-substituted, and non-substituted TAGs. The reaction conditions for transacylation with TAGs and short-chain FAs were optimized to improve transacylation ratios. The introduction ratios of C4:0, C5:0, and C6:0 into trilaurin were increased to 52.4, 42.5, and 34.1%, respectively, by extending the reaction time. Transacylation between TAGs and short-chain FAs was further examined by using Lipase PL. C4:0 was introduced at 51.1%, the same ratio as for Lipozyme RM-IM. When C5:0 and C6:0 were used as the FA substrate, the transacylation ratios obtained were 47.7 and 43.4%, respectively, higher than those for Lipase RM-IM. Lipase PL is therefore useful for introducing short-chain FAs into TAGs.

Novel fractionation method for squalene and phytosterols contained in the deodorization distillate of rice bran oil

Since deodorization distillate, a by-product of rice bran oil production, contains squalene (ca. 8%) and phytosterols (ca. 4%) as unsaponifiable components, the concentration of those materials for their use in the cosmetics and food industries is desirable. In the present work, a novel fractionation method of concentrating squalene and phytosterols from deodorization distillate or the unsaponifiable components of the deodorization distillate without oxidative deterioration was examined. Supercritical fluid extraction (SFE) with supercritical carbon dioxide was investigated under the following conditions: temperature, 30 degrees C; pressure, 100 kg/cm(2); flow rate of carbon dioxide, 7 mL/min. Under these conditions, squalene was effectively concentrated to 25% with nearly quantitative recovery, and then a more highly concentrated squalene (ca. 50% purity) was obtained by using a supercritical fluid chromatography (SFC) with silica gel packed into the extraction vessel. In addition, squalene with ca. 68% purity could be obtained by repeating the SFC twice. After the saponification of the deodorization distillate, followed by solvent fractionation with hexane, highly purified phytosterols (97% purity) could be obtained, and highly purified squalene (81% and 100% purity) could be also obtained by using SFC combined with the solvent fractionation technique for the unsaponifiable materials. Therefore, it is considered that the present fractionation method combined with SFC and solvent fractionation is an effective means of concentrating squalene and phytosterols.