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The content and distribution of melanin in the epidermis determines the wide variety of skin colors associated with ethnic/racial diversity. Although it was previously reported that qualitative changes in keratinocyte‐derived exosomes regulate melanocyte pigmentation in vitro, their practical involvement, especially in skin color development in vivo, has remained unclear. To address this unexplained scientific concern, the correlation of epidermal exosomes isolated from human skin tissues with melanosomal protein expression levels was demonstrated in this study for the first time. After confirming the quantitative effect of human keratinocyte‐derived exosomes on human melanocyte activation, even in the absence of ultraviolet B (UV‐B) exposure, the impact of exosomes secreted from UV‐B‐irradiated keratinocytes on melanogenesis was consistently detected, which suggests their constitutive role in regulating cutaneous pigmentation. Additionally, both a specific exosome secretion inducer and a suppressor were consistently found to significantly control melanin synthesis in a co‐culture system composed of keratinocytes and melanocytes as well as in an ex vivo skin culture system. These results suggest that quantitative changes, in addition to already known qualitative changes, in exosomes secreted from human epidermal keratinocytes homeostatically regulate melanogenic activity in a paracrine manner, which leads to skin color determination. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of perilla extract on urinary symptoms in spontaneously hypertensive rats as a model of spontaneous overactive bladder. Methods: Spontaneously hypertensive rats were randomly divided into two groups and fed either a control diet or a perilla extract‐containing diet. Cystometry, gene expression and histological analyses were carried out to evaluate the effects of perilla extract after 2‐week feeding of either the control or the perilla extract diet. The expression of inflammation‐related genes in the human urothelial cell line HT‐1376 and the normal human bladder epithelial cell was measured after the treatment with perillaldehyde, the main component of perilla extract, or perillic acid, the final metabolite of perillaldehyde. Results: A significant 27% increase in the micturition interval and decreased expression of nerve growth factor, tumor necrosis factor‐α, interleukin‐1β and transient receptor potential V1 were observed in the perilla group compared with the control group. The level of uroplakin 3A was 40% higher in the perilla group than in the control group. The urothelium in the control group was thin or defective, but it was almost completely intact in the perilla group. Perillaldehyde and perillic acid suppressed the induction of nerve growth factor and tumor necrosis factor‐α by interleukin‐1β in HT‐1376 and normal human bladder epithelial cells. Conclusions: The present findings suggest that perilla extract improves frequent urination, and this improvement seems to be mediated, at least in part, by enhancement of the urothelial presence and by the anti‐inflammatory effects of perilla. [ABSTRACT FROM AUTHOR]

Diacylglycerol acyltransferase (DGAT) catalyzes the final step of triacylglycerol (TAG) synthesis, and is considered as a potential target to control hypertriglyceridemia or other metabolic disorders. In this study, we found that the extract of rose petals suppressed TAG synthesis in cultured cells, and that the extract showed DGAT inhibitory action in a dose-dependent manner. Fractionation of the rose extract revealed that the DGAT inhibitory substances in the extract were ellagitannins; among them rugosin B, and D, and eusupinin A inhibited DGAT activity by 96, 82, and 84% respectively, at 10 μM. These substances did not inhibit the activities of other hepatic microsomal enzymes, glucose-6-phosphatase and HMG-CoA reductase, or pancreatic lipase, suggesting that ellagitannins inhibit DGAT preferentially. In an oral fat load test using mice, postprandial plasma TAG increase was suppressed by rose extract; TAG levels 2 h after the fat load were significantly lower in mice administered a fat emulsion containing rose extract than in control mice (446.3 ± 33.1 vs 345.3 ± 25.0 mg/dL, control vs rose extract group; P < 0.05). These results suggest that rose ellagitannins or rose extract could be beneficial in controlling lipid metabolism and used to improve metabolic disorders. [ABSTRACT FROM AUTHOR]

The article discusses a study investigating the association of Receptor for advanced glycation end products (RAGEs) protein or gene expression levels with cell inflammation, and apoptosis of human skin. Topics include composition of RAGE with one extracellular 'V'-type and two 'C'-type immunoglobulin domains, RAGE having distinct biological functions such as inflammatory reactions, host defenses, and efferocytosis functions, and addressal of gene expression patterns in the epidermis.

We investigated the effects of continuous ingestion of a catechin-rich beverage in patients with type 2 diabetes who were not receiving insulin (Ins) therapy in a double-blind controlled study. The participants ingested green tea containing either 582.8 mg of catechins (catechin group; n = 23) or 96.3 mg of catechins (control group; n = 20) per day for 12 weeks. At week 12, the decrease in waist circumference was significantly greater in the catechin group than in the control group. Adiponectin, which is negatively correlated with visceral adiposity, increased significantly only in the catechin group. Although the increase in Ins at week 12 was significantly greater in the catechin group than in the control group, no apparent difference was noted between the two groups in glucose and hemoglobin A1c. In patients treated with insulinotropic agents, the increase in Ins at week 12 was significantly greater in the catechin group than in the control group. This significant increase in Ins levels was observed only in the catechin group. In the catechin group receiving other treatments, Ins levels remained unchanged. In addition, in patients treated with insulinotropic agents, the decrease in hemoglobin A1c at week 12 was significantly greater in the catechin group than in the control group. These results suggest that a catechin-rich beverage might have several therapeutic uses: in the prevention of obesity; in the recovery of Ins-secretory ability; and, as a way to maintain low hemoglobin A1c levels in type 2 diabetic patients who do not yet require Ins therapy.Obesity (2009) 17 2, 310–317. doi:10.1038/oby.2008.505 [ABSTRACT FROM AUTHOR]

This study examines the effect of diacylglycerol (DAG) oil consisting mainly of 1,3-species on fat oxidation as a possible mechanism for anti-obesity. We examined the following: (1) the long-term (23-week) effects of a DAG oil diet on the development of obesity; (2) the effect of a single ingestion of DAG oil on fat oxidation; and, (3) the short-term (2-week) effect of a DAG oil diet on fat metabolism in rats. Rats fed a DAG oil diet accumulated significantly less body fat compared to rats fed a triacylglycerol (TAG) oil diet, each oil possesses a similar fatty acid composition. More 14C-CO2 was expired and less 14C-radioactivity was incorporated into visceral fat after administration of a tracer emulsion containing 1,3-[oleoyl-1-14C] diolein compared to [carboxyl-14C] triolein. Indirect calorimetry showed respiratory quotients were significantly lower in the DAG oil diet group than in the TAG oil diet group. More 14C-CO2 was expired and less 14C-radioactivity was incorporated into visceral fat in the DAG oil diet group than in the TAG oil diet group after a single intragastric administration of [carboxyl-14C] triolein. These results suggest the following. (1) DAG oil has an inhibitory effect on diet-induced fat accumulation. (2) 1,3-DAG, a major component of DAG oil, is more susceptible to oxidation. (3) A short-term ingestion of DAG oil increases fat utilization at the whole body level and results in increased oxidation of dietary fat. The stimulated fat oxidation might be one explanation for the anti-obesity effect of long-term DAG oil ingestion. [ABSTRACT FROM AUTHOR]

The article discusses a study regarding the body fat reducing effect and cardiovascular risk reduction property of green tea extracts (GTE) high in catechins. The study was performed on Japanese men and women with visceral fat-type obesity, who were instructed to ingest GTE high in catechins in addition to their usual dietary intake and normal physical activity. Research proved that continuous ingestion of GTE decreases obesity and cardiovascular disease risks.

Several recent studies have demonstrated that dietary DAG oil rich in 1,3-species suppresses the postprandial increase of serum TAG level and decreases body fat accumulation, compared with TAG oil. To clarify the mechanisms underlying the beneficial effects of DAG, we investigated the metabolic features of DAG in the small intestine with regard to the digestion pathway in the lumen and the TAG-synthesis pathway in the mucosa. When intraduodenally infused as an emulsion, TAG was digested to 1,2-DAG, 2-MAG, and FFA, whereas 1,3-DAG was digested to 1(3)-MAG and FFA. When assessed by the incorporation of [1-14C]linoleic acid in lipids, the mucosal TAG-synthesis was significantly reduced by DAG infusion compared with TAG infusion. However, the mucosal 1,3-DAG synthesis was remarkably increased in the DAG-infused rats. The total amount of mucosal 1,3-DAG was also increased (4.5-fold) after DAG infusion compared with that after TAG infusion. Next, we examined the synthesis pathway of 1,3-DAG. In cultures of the everted intestinal sacs, 1,3-DAG production required the presence of 1-MAG, suggesting that the 1,3-DAG synthesis was due to acylation of 1(3)-MAG in the DAG-infused rats. Furthermore, measurements of DAG acyltransferase activity indicated that 1,3-DAG was little utilized in TAG synthesis. These findings suggest that features of 1,3-DAG digestion and assimilation in the intestine may be responsible for the reduction of the postprandial serum TAG level by dietary DAG. [ABSTRACT FROM AUTHOR]