A number of studies have demonstrated the ability of free fatty acids to activate taste cells and elicit behavioral responses consistent with there being a taste of fat. Here I show for the first time that long chain unsaturated free fatty acid, linoleic acid, depolarizes taste cells and elicits a robust intracellular calcium rise via the activation of transient receptor potential channel type M5. The linoleic acid-induced responses depend on G protein-phospholipase C pathway indicative of the involvement of G protein-coupled receptors in the transduction of fatty acids. Mice lacking transient receptor potential channel type M5 exhibit no preference for and show reduced sensitivity to linoleic acid. Together, these studies show that transient receptor potential channel type M5 plays an essential role in fatty acid transduction and suggest that fat may reflect a bona fide sixth primary taste. Studies to identify the types of taste cells that respond to fatty acids show that both type II and type III taste cells express fatty acid-activated receptors. Fatty acids elicit robust intracellular calcium rise primarily in type II taste cells and a subset of type III taste cells. However, a significant subset of type II taste cells respond to high potassium chloride, which has been broadly used as the indicator for type III taste cells as well, suggesting the expression of voltage-gated calcium channels in these cells. This finding conflicts with previous studies that type II taste cells lack voltage-gated calcium channels. To explore if voltage-gated calcium channels are expressed in subsets of type II taste cells, transgenic mice with type II or III taste cells marked by green fluorescent proteins are used. Results show that a subset of type II taste cells exhibit voltage-gated calcium currents, verifying the expression of voltage-gated calcium channels in these cells. These results question the utility of being able to use high potassium chloride solution to identify unequivocally type III taste cells within the taste buds. A model for the transduction of fatty acids in taste cells consistent with these findings and our previous data is presented.

Indiana University-Purdue University Indianapolis (IUPUI) / Chronic consumption of a high-fat diet is a lifestyle factor that increases the risk for cognitive impairment (Granholm et al., 2008; Greenwood & Winocur, 2005; Mattson, 2004; Winocur & Greenwood, 2005). A high-fat diet appears to facilitate cognitive impairment through the promotion of insulin resistance (Greenwood & Winocur, 2005; Stranahan et al., 2008; Winocur & Greenwood, 2005). A gap in the literature is an established timeframe of the progression and underlying mechanism, which study in animals would better afford. Furthermore, A limited number of studies have investigated the relationship between a high-fat diet and behavioral dysregulation such as anxiety and depression. The 1st aim of the study was to determine if consumption of a high-fat diet leads to cognitive impairment and behavioral dysfunction at 3, 8, or 13 weeks of consumption. The 2nd aim was to determine if cholesterol levels and HBP activity are aberrantly increased in specific regions in mice that display feeding induced cognitive/behavioral dysfunction. Consumption of the experimental specialty diets produced a number of significant behavioral effects. These significant effects began to emerge after only 3 weeks of low-and high-fat feeding with increased anxiety-like behavior displayed higher in the high-fat diet group for the Elevated Plus Maze and Open Field Test. There was increased thigmotactic behavior and floating in the low-fat diet group in the Morris Water Maze (MWM) task, therefore making cognitive assessment uninterpretable. This pattern in the behavioral tasks were more robust in the 8 week group and alleviated in the 13 week group. There was only a significant difference in depression-like symptoms in the Forced Swim (FS) Task in the 3 week group. Cholesterol analysis is still under review in Dr. Elmendorf’s lab to correlate cholesterol levels and cognitive/behavioral impairment.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第18695号 / 農博第2092号 / 新制||農||1029(附属図書館) / 学位論文||H27||N4889(農学部図書室) / 31628 / 京都大学大学院農学研究科食品生物科学専攻 / (主査)教授 伏木 亨, 教授 河田 照雄, 教授 安達 修二 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

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This study was conducted to determine the extent to which changes in dietary fiber consumption affect weight and body fat percentage (BF%) over time. An auxiliary objective was to examine the influence of age, total caloric intake, and physical activity (PA) on the relationship between changes in fiber intake and changes in body composition over time. Design/ Subjects: Prospective cohort design with baseline and follow-up assessments 20 months apart and 252 middle-aged women (40.1±3.0 y). Diet, particularly caloric and fiber intake, was measured using 7-day weighed food records. Body fat was assessed via the Bod Pod, and PA was measured objectively using MTI accelerometers over seven consecutive days. Statistical Analysis: Changes in weight, BF%, and fiber intake were calculated by subtracting baseline measurements from those taken at 20 months. Regression analysis was used to determine the extent to which baseline fiber intake/1000 kcal and changes in fiber intake/1000 kcal were predictive of changes in body weight and BF%. Partial correlation was employed to ascertain the effect of controlling for each of the potential confounding variables on the fiber and body composition associations. Results: Across the study, there were significant changes in all variables. For every increase of one gram of fiber/1000 kcal consumed, weight decreased by 0.55 lb (P=0.0061) and BF% decreased by 0.25 percentage point (P=0.0052). Baseline fiber intake/1000 kcal was not predictive of changes in body weight or BF% over the 20 month period. Conclusions: Increasing dietary fiber intake may be an effective means of weight management in middle-aged women.

Studies have shown that overexpression of C1q TNF-related protein-3 (CTRP3) in mice fed a high alcohol diet can protect the animal from developing alcoholic fatty liver disease (ALD). Preliminary data from a recent study, however, indicated that overexpression of CTRP3 coupled with a high fat diet may cause kidney damage, including the development of (apparent) hyperlipidemic renal tubular vacuolization. If these findings are correct, using CTRP3 as a treatment for ALD would require careful monitoring of the patient diet to insure they limited the amount of fat in their diet. This recent study, however, utilized paraffin embedded kidney tissue. The processing required for paraffin embedding removes lipids/fat from the tissue. Thus, it is possible that what were assumed to be fat vacuoles in the kidney tubules may have been vacuoles unrelated to fat deposition, which represent a different aspect of tissue damage. Adipophilin and/or perilipin are proteins found in the membranes of lipocytes and membrane bound vesicles of fat. Immunohistochemical staining for adipophilin and/or perilipin 1 was used to determine if the damage seen in kidneys from the previous study was related to fat deposition or some other damaging factor. This information can inform further studies to determine how to proceed to safely administer CTRP3 to patients with ALD without damaging their kidneys.

Diet and lifestyle choices play a vital role in the overall health of an individual. There are many types of diets with varying instructions on what kind and how much of a food, or food group, should be eaten. This cross sectional study focused on possible health benefits of a vegetarian diet in regards to the body composition of non-vegetarian and vegetarian women. Total meat, poultry, seafood, and fish (MPSF) intake were separated into three categories to compare low-to-very-low, moderate, and high intake. Anthropometric measurements collected included waist to hip ratio (WHR), weight, height, and percentage of body fat. No significant differences were found between the vegetarian and non-vegetarian categories BMI, body fat percentage, or WHR. Conclusions found by previous research were not supported by the results of this research. Factors including geographic location and socioeconomic status could impact the availability of healthy food for both vegetarians and non-vegetarians.

The purpose of these studies was to evaluate the effects of a dietary fat supplementation on growth, reproduction and performance characteristics of replacement beef heifers reared in different management systems (pasture and dry lot conditions). The objectives were (1) to quantify changes in body composition traits and growth performance of replacement beef heifers fed different levels of fat in the supplemented diet,(2) to determine the reproductive performance of heifers supplemented with dietary fat in either a ryegrass pasture system or a dry lot system, and (3) to determine the value of real-time ultrasound technology (RTU) as an alternative technology to assist producers in the decision making process within replacement beef heifer programs. Over the three year study, we observed that both high (3 - 5%) and low (1.5 ? 2.5%)levels of dietary fat supplementation of replacement heifers did not have a negative affect in reproductive performance and body composition traits significantly, compared to controls (pasture-base, no supplementation. However, a positive response with respect to some body composition traits was observed in animals fed the higher level of dietary fat in 2004 and 2005 studies. Overall, growth of animals grazing ryegrass outperformed animals supplemented with dietary fat in a dry lot system; yet when dietary fat supplementation was integrated with a ryegrass pasture system, besides the positive effects in body composition traits metabolic changes in relevant reproduction hormones were observed with the addition of dietary fat treatment. Finally, the use of information on body composition traits of replacement beef heifers through the use of real-time ultrasound technology in the decision-making process resulted in a small financial return in these studies. However, the use of this alternative technology in a replacement beef heifer program may have additional value beyond the limited feeding periods reported here. These may include, a greater ability to predict heifer fertility as linked to growth and developmental characteristics (e.g., body composition traits), yet this requires further study.

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